In the past decade or so,AI(artificial intelligence)technology has been growing with such a mesmerizing speed that today its presence in almost any industry that deals with any huge sheer volume of data is taking adva...In the past decade or so,AI(artificial intelligence)technology has been growing with such a mesmerizing speed that today its presence in almost any industry that deals with any huge sheer volume of data is taking advantage of AI by integrating it into their day-to-day operation.Meanwhile,seven billion people worldwide shape the world’s energy system and directly impact the fundamental drivers of energy,both renewable and non-renewable sources,to meet the demand for electricity from them.These energy sources can be reached from nature such as solar,wind,etc.,and human-made such as NPPs(nuclear power plants)in the form of either fission as an old technology since the Manhattan project and in the near future as fusion in the form of magnetic or inertial confinements.Meanwhile,AI controlling nuclear reactors are about to happen.The basic idea is to apply AI with its two subset components as ML(machine learning),and DL(deep learning)techniques to go through the mountains of data that come from a reactor,spot patterns in it,and calling them to the unit’s human attention operators is not invadable either.Designers of such nuclear reactors will combine simulation and real-world data,comparing scenarios from each to develop“confidence[in]what they can predict and what is the range of uncertainty of their prediction”.Adding that,in the end,the operator will make the final decisions in order to keep these power plants safe while they are in operation and how to secure them against cyber-attack natural or human-made disasters.In this short communication article,we would like to see how we can prove some of these concepts;then a NPP manufacturer can pick it up and use it in their designs of a new generation of these reactors.展开更多
This article is focused on technical and economic evaluation of more than 6-years experiences of operating the Waste Heat Recovery technology—the manner and system of flue gas processing generated in the combustion p...This article is focused on technical and economic evaluation of more than 6-years experiences of operating the Waste Heat Recovery technology—the manner and system of flue gas processing generated in the combustion process in heat & power plants, cogeneration units, etc., which burn the gaseous fuel, primarily natural gas, or methane, biogas, geothermal gas, or other gaseous mixtures containing hydrogen. The solution proposes a more effective and non-traditional use of gaseous fuel for heating, the flue gases of which are processed in order to extract additional utilisable heat, with potential elimination of CO2 from them. Deploying of the heating plant in an island regime (OFF-GRID) enables definition of the benefits brought by the 3 years of operational experience and presents visions for the future offering the possibility to utilise the support energy services at the municipal as well as regional level.展开更多
This paper presents a case study for a complex contaminated groundwater site impacted by a historical release of chlorinated solvents in Silicon Valley, California. The original conceptual site model (CSM) inferred a ...This paper presents a case study for a complex contaminated groundwater site impacted by a historical release of chlorinated solvents in Silicon Valley, California. The original conceptual site model (CSM) inferred a contaminant migration pathway based on the groundwater gradient interpreted from groundwater elevation data, which is based on the underlying assumption that the subsurface conditions are homogeneous. However, the buried channel deposits render the underlying geology highly heterogeneous, and this heterogeneity plays a significant role in the subsurface migration of contaminants. Chemical fingerprinting evidence suggested that contamination at the downgradient property boundary was related to an off-site contaminant source. But, this alone was not a compelling argument. However, Environmental Sequence Stratigraphy (ESS), a geology-based environmental forensic technique, was applied to define the permeability architecture or the “plumbing” that controls subsurface fluid flow and contaminant migration. First, the geologic and depositional setting was synthesized based on regional geologic data, and representative facies models were identified for the site. Second, the existing CSM and site lithology data were reviewed and existing lithology data were graphically presented to display vertical grain-size patterns. This analysis focused on the nexus between the depositional environment and the site-specific subsurface data resulting in correlations/interpretations between and beyond data points that are based on established stratigraphic principles. The depositional environment results in buried river channels as the primary control on subsurface fluid flow, which defines hydrostratigraphic units (or HSUs). Finally, a hydrostratigraphic CSM that includes maps and cross sections was constructed to depict the HSUs present as a framework to integrate hydro-geology and chemistry data. This study demonstrates that: 1) Highly per-meable buried river channel deposits control subsurface fluid flow and contaminant transport, and have distinct chemical constituents and concentrations (i.e., they represent distinct HSUs), 2) Mapping of such HSUs is feasible with existing boring log data, 3) In settings such as the Santa Clara Valley where groundwater flow is governed by subsurface channel deposits, a hydrostratigraphic mapping approach is superior to a depth-based aquifer zonation approach, and 4) For heterogeneous subsurface, a detailed geology-based definition of the subsurface is an integral component of an environmental forensic analyses to determine contaminant source(s) and pathways.展开更多
Rice is very sensitive to low zinc(Zn) supply in submerged paddy soils and Zn deficiency is one of the major limiting factors in determining rice production in India. A field experiment was conducted during the summer...Rice is very sensitive to low zinc(Zn) supply in submerged paddy soils and Zn deficiency is one of the major limiting factors in determining rice production in India. A field experiment was conducted during the summer-rainy seasons of 2009 and 2010 at the research farm of the Indian Agricultural Research Institute, New Delhi, to determine the effects of summer green manure crops and Zn fertilizers on diethylenetriaminepentaacetic acid(DTPA)-extractable(available) Zn concentration in soil and total Zn content in Basmati rice cultivar Pusa Basmati 1 at periodic intervals. Summer green manure crops included Sesbania aculeata(Dhaincha),Crotalaria juncea(Sunhemp), and Vigna unguiculata(Cowpea) and the Zn fertilizers used were ethylenediaminetetraacetic acid(EDTA)-chelated Zn, ZnSO4·7H2O, ZnSO4·H2O, ZnO, and ZnSO4·7H2O + ZnO. Beneficial effects of summer green manure crops and Zn fertilizers on DTPA-extractable Zn concentration in soil and total Zn content in dry matter of Basmati rice at periodic intervals were observed, with significant increases in all the determined parameters, in comparison with those in the control(no Zn application or summer fallow). The rate of increase varied among summer green manure crops and Zn fertilizers during both years. Among the summer green manures, incorporation of S. aculeata led to a significant increase in mean Zn content in Basmati rice grain and straw when compared with C. juncea, V. unguiculata, and summer fallow treatments. Among the Zn fertilizers, significant increases in Zn content in Basmati rice dry matter and DTPA-extractable Zn concentration in soil during various growth stages of the plant were recorded with EDTA-chelated Zn application, followed by the application of ZnSO4·7H2O, ZnSO4·H2O, ZnSO4·7H2O + ZnO, ZnO,and no Zn. The highest mean Zn content in Basmati rice grain and straw was recorded with EDTA-chelated Zn application in 2009 and 2010, respectively. The application of ZnSO4·7H2O was the second best treatment after EDTA-chelated Zn;however, it was statistically inferior to EDTA-chelated Zn. The lowest values were recorded with the control(no Zn application) during both years of study. The amount of Zn concentration in soil was found to be significantly positively correlated with the Zn content in Basmati rice dry matter during both years. Significantly higher levels of residual fertility in soil after the harvest of Basmati rice were observed with application of EDTA-chelated Zn and incorporation of S. aculeata when compared with those of other Zn sources and summer green manures.展开更多
Nitrogen(N)and phosphorus(P)are essential nutrients and can significantly impact primary productivity of the ecosystem causing water environmental problems.However,their cycling mechanisms are not well understood in a...Nitrogen(N)and phosphorus(P)are essential nutrients and can significantly impact primary productivity of the ecosystem causing water environmental problems.However,their cycling mechanisms are not well understood in alpine mountains with climate change.Hence,94 samples of river water were collected from 2018 to 2020 in the headwaters of the Shule River Basin to assess the nutrients spatiotemporal distribution and combined ap-proach of water quality index to assess water quality and potential sources.The findings depict that high nutrient concentrations were found to coincide with snowmelt and glacial meltwater and rainfall recharge periods,while total flux peaked from June to September due to increased runoff.Notably,total nitrogen(TN)concentrations were significantly higher near the town,primarily attributed to the replenishment of nitrate(NO_(3)^(‒)-N)from live-stock manure.The high total P(TP)was near the glacier,which was attributed to the transportation of glacial sediments into the river,and pH was another critical factor.N was the primary nutrient limiting factor for the growth of phytoplankton in river water.Although the migration and transport of nutrients have altered with climate change,river water quality is good in alpine mountains based on an overall evaluation.These findings contribute to enriching nutrient datasets and highlight the importance of water resource management and water quality assessment in sensitive and fragile alpine mountains.展开更多
Curcuma is a traditional Chinese medicine that has been utilized for centuries in the treatment of various diseases. Terpenoids, particularly monoterpenes and sesquiterpenes, constitute the primary bioactive component...Curcuma is a traditional Chinese medicine that has been utilized for centuries in the treatment of various diseases. Terpenoids, particularly monoterpenes and sesquiterpenes, constitute the primary bioactive components of the essential oil derived from Curcuma species.Among these, curdione—one of the key active constituents—has been identified in 25 Curcuma species, with the highest concentration reported in the rhizome essential oil of Curcuma trichosantha Gagnep. Curdione can also be synthesized through chemical methods,and its regio-and stereo-selectivity can be further optimized via chemo-bio transformations.This compound demonstrates significant therapeutic potential, including anticancer, antithrombotic, anti-inflammatory, anti-viral, anti-fungal, anti-diabetic, and multi-organ protective properties. Despite these promising biological activities, its clinical application is hindered by poor water solubility and potential toxicity. This review summarizes current knowledge on the natural sources, chemical synthesis, chemo-bio transformations, metabolism, pharmacokinetics, pharmacological effects, potential toxicities, and molecular mechanisms of curdione. Furthermore, perspectives on future drug development are discussed with the aim of promoting the clinical translation of this promising natural compound.展开更多
Accurate identification of sediment sources and erosion hotspots is crucial for implementing targeted soil and water conservation measures.This study analyzed the temporal dynamics of sediment source contributions dur...Accurate identification of sediment sources and erosion hotspots is crucial for implementing targeted soil and water conservation measures.This study analyzed the temporal dynamics of sediment source contributions during seven rainfall events(A_(1)–A_(7))that generated both runoff and suspended sediment at the outlet of the Hantaichuan watershed,located in the wind–water erosion crisscross region of the northern Loess Plateau,China.A total of 82 suspended sediment samples were collected at the Xiangshawan hydrological station during 2021 and 2022.Additionally,145 soil samples were collected from three primary potential sources:sandy soil,loess soil,and Pisha sandstone.Mid-infrared(MIR)spectroscopy and geochemical fingerprinting were used to trace and quantify sediment sources.For MIRbased source apportionment,twelve predictive models were developed using partial least squares regression(PLSR)and support vector machine regression(SVMR)in combination with six spectral preprocessing techniques.The PLSR model with first-derivative Savitzky–Golay(SGD1)preprocessing achieved the best performance.Source apportionment results indicated that Pisha sandstone was the dominant sediment source(44.00%–72.23%),followed by sandy soil(14.23%–37.00%)and loess soil(10.01%–24.00%).Among the analyzed rainfall events,the contribution of Pisha sandstone was lowest in the small flow magnitude event A3(57.53%)and highest in the large flow magnitude event A6(63.48%),suggesting that sediment source composition was strongly controlled by rainfall event magnitude.Both MIR spectroscopic and geochemical fingerprinting methods showed high consistency,confirming MIR spectroscopy as a reliable,non-destructive,and cost-effective alternative for rapid sediment source apportionment and for supporting erosion control prioritization in highly erodible catchments.展开更多
The identification of rock mass hazard sources is fundamental for preventing rockfall and landslide disasters in mountainous regions,with rock mass structural characteristics playing a vital role in hazard assessment....The identification of rock mass hazard sources is fundamental for preventing rockfall and landslide disasters in mountainous regions,with rock mass structural characteristics playing a vital role in hazard assessment.In this study,terrestrial laser scanning(TLS)and unmanned aerial vehicle(UAV)technologies were integrated to enhance the evaluation methodology for rock mass hazard sources,focusing on the Sichuan Yanjiang Expressway project in China.The findings demonstrate that TLS-UAV technology enhanced both spatial coverage and data density in slope modeling.Through integrated algorithmic analysis,rock discontinuities within heterogeneous datasets were systematically identified,enabling quantitative extraction and statistical analysis of key geometric parameters,including orientation,trace length,spacing,and roughness.Furthermore,quantitative models were developed for cohesion,friction angle and the morphology parameter M of in situ discontinuities,respectively,facilitating efficient mechanical parameter acquisition.A novel rock mass hazard index(RHI)was developed incorporating discontinuity geometric rating(DGR),discontinuity mechanical rating(DMR),and slope mass rating(SMR).Field validation confirmed the methodology's effectiveness in evaluating risk levels and spatial heterogeneity of rock mass hazard sources,revealing the contribution of different discontinuity sets to the rock mass hazard and identifying the primary discontinuity sets controlling instability mechanisms.This study is of great significance for evaluating discontinuity-controlled rock mass hazard sources and preventing rockfall disasters.展开更多
The real-time and accurate calculation of electricity indirect carbon emissions is not only the critical component for quantifying the carbon emission levels of the power system but also an effective mean to guide ele...The real-time and accurate calculation of electricity indirect carbon emissions is not only the critical component for quantifying the carbon emission levels of the power system but also an effective mean to guide electricity users in carbon reduction and promote power industry low-carbon transformation.Fundamentally,calculating indirect carbon emissions involves allocating direct carbon emission data from the power source side,indicating that accurate indirect emission results rely on the precise measurement of power source emissions.However,existing research on indirect carbon emissions in large-scale power systems rarely accounts for variations in carbon emission characteristics under different operating conditions of power sources,such as rated/non-rated operating conditions and ramping up/down conditions,making it difficult to reflect source-side and load-side carbon emission information variation during providing ancillary services.Quadratic and exponential functions are proposed to characterize the energy consumption profiles of coal-fired and gas-fired power generation,respectively,to construct a refined carbon emission model for power sources.By leveraging the theory of power system carbon flow,we analyze how variable operating conditions of power sources impact indirect carbon emissions.Case studies demonstrate that changes in power source emissions under variable conditions have a significant effect on the indirect carbon emissions of power grids.展开更多
Historical mining activities often lead to continuing wide spread contaminants in both groundwater and surface water in previously operational mine site areas. The contamination may continue for many years after closi...Historical mining activities often lead to continuing wide spread contaminants in both groundwater and surface water in previously operational mine site areas. The contamination may continue for many years after closing down the mining activities. The essential first step for sustainable management of groundwater and development of remediation strategies is the unknown contaminant source characterization. In a mining site, there are multiple species of contaminants involving complex geochemical processes. It is difficult to identify the potential sources and pathways incorporating the chemically reactive multiple species of contaminants making the source characterization process more challenging. To address this issue, a reactive transport simulation model PHT3D is linked to a Simulated Annealing based the optimum decision model. The numerical simulation model PHT3D is utilized for numerically simulating the reactive transport process involving multiple species in the former mine site area. The simulation results from the calibrated PHT3D model are illustrated, with and without incorporating the chemical reactions. These comparisons show the utility of using a reactive, geochemical transport process’ simulation model. Performance evaluation of the linked simulation optimization methodology is evaluated for a contamination scenario in a former mine site in Queensland, Australia. These performance evaluation results illustrate the applicability of linked simulation optimization model to identify the source characteristics while using PHT3D as a numerical reactive chemical species’ transport simulation model for the hydro-geochemically complex aquifer study area.展开更多
A major challenge of any optimization problem is to find the global optimum solution. In a multi-dimensional solution space which is highly non-linear, often the optimization algorithm gets trapped around some local o...A major challenge of any optimization problem is to find the global optimum solution. In a multi-dimensional solution space which is highly non-linear, often the optimization algorithm gets trapped around some local optima. Optimal Identification of unknown groundwater pollution sources poses similar challenges. Optimization based methodology is often applied to identify the unknown source characteristics such as location and flux release history over time, in a polluted aquifer. Optimization based models for identification of these characteristics of unknown ground-water pollution sources rely on comparing the simulated effects of candidate solutions to the observed effects in terms of pollutant concentration at specified sparse spatiotemporal locations. The optimization model minimizes the difference between the observed pollutant concentration measurements and simulated pollutant concentration measurements. This essentially constitutes the objective function of the optimization model. However, the mathematical formulation of the objective function can significantly affect the accuracy of the results by altering the response contour of the solution space. In this study, two separate mathematical formulations of the objective function are compared for accuracy, by incorporating different scenarios of unknown groundwater pollution source identification problem. Simulated Annealing (SA) is used as the solution algorithm for the optimization model. Different mathematical formulations of the objective function for minimizing the difference between the observed and simulated pollutant concentration measurements show different levels of accuracy in source identification results. These evaluation results demonstrate the impact of objective function formulation on the optimal identification, and provide a basis for choosing an appropriate mathematical formulation for unknown pollution source identification in contaminated aquifers.展开更多
In the paper, Ablowitz–Ladik hierarchy with new self-consistent sources is investigated. First the source in the hierarchy is described as φnφn+1, where φnis related to the Ablowitz–Ladik spectral problem, instea...In the paper, Ablowitz–Ladik hierarchy with new self-consistent sources is investigated. First the source in the hierarchy is described as φnφn+1, where φnis related to the Ablowitz–Ladik spectral problem, instead of the corresponding adjoint spectral problem. Then by means of the inverse scattering transform, the multi-soliton solutions for the hierarchy are obtained. Two reductions to the discrete mKdV and nonlinear Schr¨odinger hierarchies with selfconsistent sources are considered by using the uniqueness of the Jost functions, as well as their N-soliton solutions.展开更多
39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.Ar...39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.ArcGIS inverse distance weight difference method was used to analyze the characteristics of pollution distribution,and single-factor pollution index,Nemerow comprehensive pollution index,ground accumulation index,and potential ecological risk index were selected to evaluate the characteristics of heavy metal pollution.Based on correlation analysis,the absolute principal component-multiple linear regression(APCS-MLR)and positive definite matrix factorization(PMF)models were used to analyze the sources of soil heavy metals.The results showed that the average concentrations of all eight heavy metals exceeded both national and Guangxi soil background values.Hg,Cd,and Zn exhibited high variation(greater than 0.5),indicating significant external disturbances,and their spatial distribution was closely related to mining activity locations.The single-factor pollution index evaluation indicated varying degrees of pollution risk for Cd,Zn,and As,with Cd and Zn being the most severe pollutants,as 69.23%and 30.77%of the samples fell into the moderate pollution or higher category.The geoaccumulation index analysis ranked the mean pollution levels of the eight elements as follows:Zn>Cd>Ni>Pb>Cu>Cr>Hg>As,with Cd and Zn showing the most severe contamination,and 51.28%of the samples exhibiting moderate or higher pollution levels.The Nemerow comprehensive pollution index evaluation showed that 74.35%of soil samples were classified as moderate to heavy pollution.The potential ecological risk index assessment indicated significant ecological risks posed by Cd and Zn,with 82.05%and 5.12%of the samples classified as causing strong to extreme ecological risks,respectively.The source apportionment analysis revealed minor differences between the two models.The APCS-MLR model identified three pollution sources and their contribution rates:anthropogenic mining sources(31.13%),parent material sources(40.38%),and unidentified sources(28.49%).The PMF model identified three pollution sources with contribution rates of anthropogenic mining sources(26.10%),parent material sources(46.96%),and a combined traffic and agricultural source(26.61%).Pb,Hg,Cd,and Zn mainly originated from mining activities;Cr,As,and Ni were primarily derived from the parent material,while Cu was predominantly attributed to traffic and agricultural sources.These findings provide a scientific basis for the prevention and control of heavy metal pollution in mining areas.展开更多
A wide range of welding and surface treatment processes involve the use of a heat source which is moving at a constant speed over the component. The numerical simulation of such processes implies a transient analysis ...A wide range of welding and surface treatment processes involve the use of a heat source which is moving at a constant speed over the component. The numerical simulation of such processes implies a transient analysis using a very refined mesh in order to follow properly the path of the heat source. The 3D-mesh size can be very large if one consider the welds length or the heat-treated surface size in industrial components. To reduce the computational time to acceptable values, several techniques have been investigated. The first type is to use analytical methods such as Rosenthal equations. The second type of solutions consists in performing a transient analysis using adaptive meshing. But, for a large proportion of the involved processes, practical experience demonstrates the existence of quasi steady state conditions over the major part of the heat source path. Numerical algorithms have therefore been developed to directly compute the steady temperature, metallurgical phase proportion and stress distributions. This paper gives a general overview of the different numerical methods used to simulate welding and surface treatment processes with a special emphasis on the steady state calculation. The benefits and limitations of each of them are discussed and applications are presented.展开更多
Per-and poly-fluoroalkyl substances(PFAS)have garnered significant global attention due to their widespread presence and potential environmental and health risks.However,research on the occurrence and environmental be...Per-and poly-fluoroalkyl substances(PFAS)have garnered significant global attention due to their widespread presence and potential environmental and health risks.However,research on the occurrence and environmental behavior of PFAS across different media remains limited.We analyzed the occurrence,distribution,sources,and ecological risks of 32 PFAS across multiple media in the Weihe River,China.The concentrations of PFAS ranged from 5.89 to 472.84 ng/L in the pore water and from 9.93 to 459.50 ng/L in surface water,exhibiting significant spatial variability(P<0.05).In contrast,the PFAS concentration range in the sediments was 0.74-1.81 ng/g dry weight,with no pronounced spatial variation in solid-phase PFAS(P>0.05).Vertically,concentrations in 33.00%of pore water samples exceeded those in surface water,showing a heterogeneous vertical distribution with enrichment at depths of 40-60 cm.The physical-chemical characteristics of PFAS and the hydrological and sedimentary processes at the basin scale were responsible for PFAS partitioning between the aquatic environment and sediments.Four major sources were identified through integrated source apportionment:industrial and domestic wastewater(58.25%),aqueous film-forming foam(18.07%),combined input from household pollution and metal plating(8.70%),and stormwater runoff and landfill leachate(14.98%).The ecological risk assessment revealed negligible risks from short-chain PFAS in surface water and pore water,whereas long-chain PFAS posed low to moderate ecological risks.Furthermore,the discharge of PFAS from the Weihe River to the Yellow River was estimated up to 708.20 kg/a.This study provides critical data informing strategies for mitigating PFAS pollution in rivers across typical arid and semi-arid areas of China.展开更多
The estimation of the Number of Sources(NoS)is a significant challenge in signal processing,particularly due to the impact of colored noise on the performance of NoS estimation.This paper proposes a Multidimensional F...The estimation of the Number of Sources(NoS)is a significant challenge in signal processing,particularly due to the impact of colored noise on the performance of NoS estimation.This paper proposes a Multidimensional Feature Network(MFNet)which is designed for NoS estimation by extracting features of the sampled received signals and Sampled Covariance Matrix(SCM).The MFNet treats the raw signal and the SCM as two different types of data,and is able to achieve NoS estimation under colored noise and imperfect array.MFNet employs the Gated Recurrent Unit(GRU)to capture sequential information from the original signal data and to construct the Pseudo Covariance Matrix(PCM).Subsequently,various dimensional features,including eigenvalues and the Gerschgorin disk radius,are extracted from both the PCM and SCM,which are then jointly input into the subsequent network.An overall accuracy of 82%can be achieved after network training.The ablation experimental results demonstrate the effectiveness of multiple inputs.And simulation results demonstrate that the proposed MFNet achieves higher estimation accuracy compared to existing algorithms and exhibits greater robustness against colored noise.展开更多
Carbon Capture,Utilization,and Storage(CCUS)technology has gained widespread attention in recent years as a critical strategy to combat global climate change,particularly in achieving carbon neutrality goals.The Guang...Carbon Capture,Utilization,and Storage(CCUS)technology has gained widespread attention in recent years as a critical strategy to combat global climate change,particularly in achieving carbon neutrality goals.The Guangdong-Hong Kong-Macao Greater Bay Area(GBA),as one of China's most economically active regions,serves as a key engine for economic growth while also facing considerable carbon emission challenges.This study analyzes the industrial emission volume and geographical distribution of key emitting enterprises in the GBA,summarizes their technological processes and main carbonemitting equipment,and provides scientific support for precise mitigation policies and low-carbon development.Based on data from 176 key emitting enterprises,the study reveals that Guangzhou and Dongguan host the largest number of such enterprises.Carbon emissions are primarily concentrated in the power sector,dominated by coal-and gas-fired power units,characterized by significant spatial dispersion and uneven distribution.Beyond the power sector,the paper industry has a high number of enterprises but lower emissions.Key facilities such as boilers,cogeneration systems,and production lines are predominantly located near tributaries rivers in Dongguan and Jiangmen.The building materials sector,primarily cement production,ranks as the second-largest emitter,with hightemperature kilns and grinding equipment,particularly rotary kilns and glass furnaces,as the main sources.The petrochemical and chemical sectors have fewer enterprises and lower emissions in the GBA,mainly located in suburban industrial clusters.Carbon emissions in the GBA exhibit distinct industry concentration and geographical distribution disparities.This study provides crucial data and theoretical insights for the development of targeted emission reduction strategies,optimization of source-sink matching,and the advancement of CCUS technologies in the region,particularly from the GBA to the northern South China Sea.展开更多
Rhodobacter sphaeroides is a purple non-sulfur bacterium that belongs to the α-3 subdivision of Proteobacteria. R. sphaeroides is a model bacterial species because of its complex genome structure and expanded metabol...Rhodobacter sphaeroides is a purple non-sulfur bacterium that belongs to the α-3 subdivision of Proteobacteria. R. sphaeroides is a model bacterial species because of its complex genome structure and expanded metabolic capabilities. The genome of R. sphaeroides consists of two circular chromosomes and five endogenous plasmids. It has the ability to grow under a wide variety of environmental conditions. It grows aerobically (~20% O2), semi-aerobically (~2% O2), and photosynthetically (under anaerobic condition plus light). It has been previously shown that many bacterial species utilize a number of alternate carbon sources for their optimal growth under a variety of growth conditions. We hypothesize that different or an additional carbon source in the minimal medium differentially affects the bacterial growth under dark-aerobic conditions. The bacterial growth kinetics and the number of cells in the bacterial culture were analyzed by measuring the optical density (OD at 600 nm) and the colony forming units (CFUs) at regular intervals of bacterial cultures. Results reveal that sodium succinate is the preferred sole carbon source for the optimal growth of R. sphaeroides. The results of growth kinetics and CFUs together concluded that from the tested carbon sources, sodium succinate is the best single carbon source in the minimal media for the optimal growth of R. sphaeroides. Interestingly, cell culture grown in SIS supplemented with sodium acetate exhibits a prolonged lag phase with the lowest ODs and CFUs that later switches to the growth-burst phase support previously discovered similar phenomenon of the growth-rate switch in the presence of acetate metabolism. Future work will utilize the aerobically grown R. sphaeroides’ cells as a biocatalyst to deplete the oxygen levels from natural gas streams and industrial gas pipelines.展开更多
In this study, the daily observational precipitation data and NCEP reanalysis data during 1951e2014, Euler and Lagrangian method were used to investigate the moisture sources of summer extreme precipitation events in ...In this study, the daily observational precipitation data and NCEP reanalysis data during 1951e2014, Euler and Lagrangian method were used to investigate the moisture sources of summer extreme precipitation events in North Xinjiang. The results show that water vapor at low and upper levels of most summer heavy rain (more than 50 mm d1 and less than 100 mm d1) in North Xinjiang are mainly transported by westerly circulation from the North Atlantic Ocean and the Eurasian continent. However, rainstorms of more than 100 mm d1, which are rarely observed, are dominated by vertically integrated moisture from the North Atlantic, Arctic Oceans, and the Eurasian continent, in addition to lowlevel moisture from the Indian Ocean. Among these sources, the anomalous low-level moisture from the Indian Ocean, which is closely associated with stronger meridional circulation, is considered to be more important with respect to rainstorms. On the days prior to rainstorm days, stronger meridional circulation leads to an anomalous pressure gradient force, which can transport low-level moisture from the Indian Ocean along the eastern periphery of the Tibetan Plateau to North Xinjiang. Furthermore, moisture from the North Atlantic, Arctic Oceans, the Eurasian continent, and the Indian Ocean converge together to influence rainstorm development in this region.展开更多
Ultrafast electron sources, which enable high spatiotemporal resolution in time-resolved electron microscopy and scanning probe microscopy, are receiving increased attention. The most widely used method for achieving ...Ultrafast electron sources, which enable high spatiotemporal resolution in time-resolved electron microscopy and scanning probe microscopy, are receiving increased attention. The most widely used method for achieving ultrafast electron sources involves irradiating metal tips by ultrashort laser pulses, causing electron beam emission via the photoelectric effect [including photon-driven(quantum) or field-driven(classical) emission]. However, the thermionic electrons emission process due to the heating effect of ultrashort lasers, particularly its dynamic aspects, has rarely been addressed in previous studies. In this paper, we improved the signal-to-noise ratio of a two-pulse correlation measurement on the tip electron emission by nearly two orders of magnitude using a delay time modulation method. This allowed us to obtain information on the temperature evolution of hot electrons and phonons in a non-equilibrium state, and to extract characteristic time scales for electron-phonon and phonon-phonon scattering. Our findings indicate that the thermionic electrons emission, unlike the instantaneous photoelectric effect, causes electron emission to lag behind the laser pulse by tens of picoseconds, thus significantly affecting the detection of ultrafast dynamics of samples. Furthermore, such a lagging effect was found to be sensitive to the local structure of the metal tip, offering new insights into the improved design of ultrafast electron sources.展开更多
文摘In the past decade or so,AI(artificial intelligence)technology has been growing with such a mesmerizing speed that today its presence in almost any industry that deals with any huge sheer volume of data is taking advantage of AI by integrating it into their day-to-day operation.Meanwhile,seven billion people worldwide shape the world’s energy system and directly impact the fundamental drivers of energy,both renewable and non-renewable sources,to meet the demand for electricity from them.These energy sources can be reached from nature such as solar,wind,etc.,and human-made such as NPPs(nuclear power plants)in the form of either fission as an old technology since the Manhattan project and in the near future as fusion in the form of magnetic or inertial confinements.Meanwhile,AI controlling nuclear reactors are about to happen.The basic idea is to apply AI with its two subset components as ML(machine learning),and DL(deep learning)techniques to go through the mountains of data that come from a reactor,spot patterns in it,and calling them to the unit’s human attention operators is not invadable either.Designers of such nuclear reactors will combine simulation and real-world data,comparing scenarios from each to develop“confidence[in]what they can predict and what is the range of uncertainty of their prediction”.Adding that,in the end,the operator will make the final decisions in order to keep these power plants safe while they are in operation and how to secure them against cyber-attack natural or human-made disasters.In this short communication article,we would like to see how we can prove some of these concepts;then a NPP manufacturer can pick it up and use it in their designs of a new generation of these reactors.
文摘This article is focused on technical and economic evaluation of more than 6-years experiences of operating the Waste Heat Recovery technology—the manner and system of flue gas processing generated in the combustion process in heat & power plants, cogeneration units, etc., which burn the gaseous fuel, primarily natural gas, or methane, biogas, geothermal gas, or other gaseous mixtures containing hydrogen. The solution proposes a more effective and non-traditional use of gaseous fuel for heating, the flue gases of which are processed in order to extract additional utilisable heat, with potential elimination of CO2 from them. Deploying of the heating plant in an island regime (OFF-GRID) enables definition of the benefits brought by the 3 years of operational experience and presents visions for the future offering the possibility to utilise the support energy services at the municipal as well as regional level.
文摘This paper presents a case study for a complex contaminated groundwater site impacted by a historical release of chlorinated solvents in Silicon Valley, California. The original conceptual site model (CSM) inferred a contaminant migration pathway based on the groundwater gradient interpreted from groundwater elevation data, which is based on the underlying assumption that the subsurface conditions are homogeneous. However, the buried channel deposits render the underlying geology highly heterogeneous, and this heterogeneity plays a significant role in the subsurface migration of contaminants. Chemical fingerprinting evidence suggested that contamination at the downgradient property boundary was related to an off-site contaminant source. But, this alone was not a compelling argument. However, Environmental Sequence Stratigraphy (ESS), a geology-based environmental forensic technique, was applied to define the permeability architecture or the “plumbing” that controls subsurface fluid flow and contaminant migration. First, the geologic and depositional setting was synthesized based on regional geologic data, and representative facies models were identified for the site. Second, the existing CSM and site lithology data were reviewed and existing lithology data were graphically presented to display vertical grain-size patterns. This analysis focused on the nexus between the depositional environment and the site-specific subsurface data resulting in correlations/interpretations between and beyond data points that are based on established stratigraphic principles. The depositional environment results in buried river channels as the primary control on subsurface fluid flow, which defines hydrostratigraphic units (or HSUs). Finally, a hydrostratigraphic CSM that includes maps and cross sections was constructed to depict the HSUs present as a framework to integrate hydro-geology and chemistry data. This study demonstrates that: 1) Highly per-meable buried river channel deposits control subsurface fluid flow and contaminant transport, and have distinct chemical constituents and concentrations (i.e., they represent distinct HSUs), 2) Mapping of such HSUs is feasible with existing boring log data, 3) In settings such as the Santa Clara Valley where groundwater flow is governed by subsurface channel deposits, a hydrostratigraphic mapping approach is superior to a depth-based aquifer zonation approach, and 4) For heterogeneous subsurface, a detailed geology-based definition of the subsurface is an integral component of an environmental forensic analyses to determine contaminant source(s) and pathways.
文摘Rice is very sensitive to low zinc(Zn) supply in submerged paddy soils and Zn deficiency is one of the major limiting factors in determining rice production in India. A field experiment was conducted during the summer-rainy seasons of 2009 and 2010 at the research farm of the Indian Agricultural Research Institute, New Delhi, to determine the effects of summer green manure crops and Zn fertilizers on diethylenetriaminepentaacetic acid(DTPA)-extractable(available) Zn concentration in soil and total Zn content in Basmati rice cultivar Pusa Basmati 1 at periodic intervals. Summer green manure crops included Sesbania aculeata(Dhaincha),Crotalaria juncea(Sunhemp), and Vigna unguiculata(Cowpea) and the Zn fertilizers used were ethylenediaminetetraacetic acid(EDTA)-chelated Zn, ZnSO4·7H2O, ZnSO4·H2O, ZnO, and ZnSO4·7H2O + ZnO. Beneficial effects of summer green manure crops and Zn fertilizers on DTPA-extractable Zn concentration in soil and total Zn content in dry matter of Basmati rice at periodic intervals were observed, with significant increases in all the determined parameters, in comparison with those in the control(no Zn application or summer fallow). The rate of increase varied among summer green manure crops and Zn fertilizers during both years. Among the summer green manures, incorporation of S. aculeata led to a significant increase in mean Zn content in Basmati rice grain and straw when compared with C. juncea, V. unguiculata, and summer fallow treatments. Among the Zn fertilizers, significant increases in Zn content in Basmati rice dry matter and DTPA-extractable Zn concentration in soil during various growth stages of the plant were recorded with EDTA-chelated Zn application, followed by the application of ZnSO4·7H2O, ZnSO4·H2O, ZnSO4·7H2O + ZnO, ZnO,and no Zn. The highest mean Zn content in Basmati rice grain and straw was recorded with EDTA-chelated Zn application in 2009 and 2010, respectively. The application of ZnSO4·7H2O was the second best treatment after EDTA-chelated Zn;however, it was statistically inferior to EDTA-chelated Zn. The lowest values were recorded with the control(no Zn application) during both years of study. The amount of Zn concentration in soil was found to be significantly positively correlated with the Zn content in Basmati rice dry matter during both years. Significantly higher levels of residual fertility in soil after the harvest of Basmati rice were observed with application of EDTA-chelated Zn and incorporation of S. aculeata when compared with those of other Zn sources and summer green manures.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0208)the National Natural Science Foundation of China(Nos.42171148 and 42330512)the Key R&D Project from the Science and Technology Department of Tibet(No.XZ202501ZY0030).
文摘Nitrogen(N)and phosphorus(P)are essential nutrients and can significantly impact primary productivity of the ecosystem causing water environmental problems.However,their cycling mechanisms are not well understood in alpine mountains with climate change.Hence,94 samples of river water were collected from 2018 to 2020 in the headwaters of the Shule River Basin to assess the nutrients spatiotemporal distribution and combined ap-proach of water quality index to assess water quality and potential sources.The findings depict that high nutrient concentrations were found to coincide with snowmelt and glacial meltwater and rainfall recharge periods,while total flux peaked from June to September due to increased runoff.Notably,total nitrogen(TN)concentrations were significantly higher near the town,primarily attributed to the replenishment of nitrate(NO_(3)^(‒)-N)from live-stock manure.The high total P(TP)was near the glacier,which was attributed to the transportation of glacial sediments into the river,and pH was another critical factor.N was the primary nutrient limiting factor for the growth of phytoplankton in river water.Although the migration and transport of nutrients have altered with climate change,river water quality is good in alpine mountains based on an overall evaluation.These findings contribute to enriching nutrient datasets and highlight the importance of water resource management and water quality assessment in sensitive and fragile alpine mountains.
基金supported by the National Natural Science Foundation of China (Nos. 82192913 and 82304851)the Scientific and Technological Innovation Project of China Academy of Chinese Medical Sciences (Nos. CI2023E002, CI2021B016, and CI2021A04801)the Fundamental Research Funds for the Central Public Welfare Research Institutes (Nos. ZZ13-YQ-055 and ZXKT22044)。
文摘Curcuma is a traditional Chinese medicine that has been utilized for centuries in the treatment of various diseases. Terpenoids, particularly monoterpenes and sesquiterpenes, constitute the primary bioactive components of the essential oil derived from Curcuma species.Among these, curdione—one of the key active constituents—has been identified in 25 Curcuma species, with the highest concentration reported in the rhizome essential oil of Curcuma trichosantha Gagnep. Curdione can also be synthesized through chemical methods,and its regio-and stereo-selectivity can be further optimized via chemo-bio transformations.This compound demonstrates significant therapeutic potential, including anticancer, antithrombotic, anti-inflammatory, anti-viral, anti-fungal, anti-diabetic, and multi-organ protective properties. Despite these promising biological activities, its clinical application is hindered by poor water solubility and potential toxicity. This review summarizes current knowledge on the natural sources, chemical synthesis, chemo-bio transformations, metabolism, pharmacokinetics, pharmacological effects, potential toxicities, and molecular mechanisms of curdione. Furthermore, perspectives on future drug development are discussed with the aim of promoting the clinical translation of this promising natural compound.
基金supported by the National Key Scientific Research Project(Grant No.2023YFC3209303)jointly funded by the National Natural Sciences Foundation of China(Grant Nos.42577406 and 42077076)the National Natural Science Foundation of China and Yellow River Water Science Research Joint Fund(Grant No.U2243211).
文摘Accurate identification of sediment sources and erosion hotspots is crucial for implementing targeted soil and water conservation measures.This study analyzed the temporal dynamics of sediment source contributions during seven rainfall events(A_(1)–A_(7))that generated both runoff and suspended sediment at the outlet of the Hantaichuan watershed,located in the wind–water erosion crisscross region of the northern Loess Plateau,China.A total of 82 suspended sediment samples were collected at the Xiangshawan hydrological station during 2021 and 2022.Additionally,145 soil samples were collected from three primary potential sources:sandy soil,loess soil,and Pisha sandstone.Mid-infrared(MIR)spectroscopy and geochemical fingerprinting were used to trace and quantify sediment sources.For MIRbased source apportionment,twelve predictive models were developed using partial least squares regression(PLSR)and support vector machine regression(SVMR)in combination with six spectral preprocessing techniques.The PLSR model with first-derivative Savitzky–Golay(SGD1)preprocessing achieved the best performance.Source apportionment results indicated that Pisha sandstone was the dominant sediment source(44.00%–72.23%),followed by sandy soil(14.23%–37.00%)and loess soil(10.01%–24.00%).Among the analyzed rainfall events,the contribution of Pisha sandstone was lowest in the small flow magnitude event A3(57.53%)and highest in the large flow magnitude event A6(63.48%),suggesting that sediment source composition was strongly controlled by rainfall event magnitude.Both MIR spectroscopic and geochemical fingerprinting methods showed high consistency,confirming MIR spectroscopy as a reliable,non-destructive,and cost-effective alternative for rapid sediment source apportionment and for supporting erosion control prioritization in highly erodible catchments.
基金support from the National Natural Science Foundation of China(Grant Nos.42177142 and 52378477)the Key Research and Development Program of Shaanxi(Grant No.2023-YBSF-486).
文摘The identification of rock mass hazard sources is fundamental for preventing rockfall and landslide disasters in mountainous regions,with rock mass structural characteristics playing a vital role in hazard assessment.In this study,terrestrial laser scanning(TLS)and unmanned aerial vehicle(UAV)technologies were integrated to enhance the evaluation methodology for rock mass hazard sources,focusing on the Sichuan Yanjiang Expressway project in China.The findings demonstrate that TLS-UAV technology enhanced both spatial coverage and data density in slope modeling.Through integrated algorithmic analysis,rock discontinuities within heterogeneous datasets were systematically identified,enabling quantitative extraction and statistical analysis of key geometric parameters,including orientation,trace length,spacing,and roughness.Furthermore,quantitative models were developed for cohesion,friction angle and the morphology parameter M of in situ discontinuities,respectively,facilitating efficient mechanical parameter acquisition.A novel rock mass hazard index(RHI)was developed incorporating discontinuity geometric rating(DGR),discontinuity mechanical rating(DMR),and slope mass rating(SMR).Field validation confirmed the methodology's effectiveness in evaluating risk levels and spatial heterogeneity of rock mass hazard sources,revealing the contribution of different discontinuity sets to the rock mass hazard and identifying the primary discontinuity sets controlling instability mechanisms.This study is of great significance for evaluating discontinuity-controlled rock mass hazard sources and preventing rockfall disasters.
基金supported by the Science and Technology Project of China Southern Power Grid Co.,Ltd.(ZBKTM20232244)the Project of National Natural of Science Foundation of China(52477103).
文摘The real-time and accurate calculation of electricity indirect carbon emissions is not only the critical component for quantifying the carbon emission levels of the power system but also an effective mean to guide electricity users in carbon reduction and promote power industry low-carbon transformation.Fundamentally,calculating indirect carbon emissions involves allocating direct carbon emission data from the power source side,indicating that accurate indirect emission results rely on the precise measurement of power source emissions.However,existing research on indirect carbon emissions in large-scale power systems rarely accounts for variations in carbon emission characteristics under different operating conditions of power sources,such as rated/non-rated operating conditions and ramping up/down conditions,making it difficult to reflect source-side and load-side carbon emission information variation during providing ancillary services.Quadratic and exponential functions are proposed to characterize the energy consumption profiles of coal-fired and gas-fired power generation,respectively,to construct a refined carbon emission model for power sources.By leveraging the theory of power system carbon flow,we analyze how variable operating conditions of power sources impact indirect carbon emissions.Case studies demonstrate that changes in power source emissions under variable conditions have a significant effect on the indirect carbon emissions of power grids.
文摘Historical mining activities often lead to continuing wide spread contaminants in both groundwater and surface water in previously operational mine site areas. The contamination may continue for many years after closing down the mining activities. The essential first step for sustainable management of groundwater and development of remediation strategies is the unknown contaminant source characterization. In a mining site, there are multiple species of contaminants involving complex geochemical processes. It is difficult to identify the potential sources and pathways incorporating the chemically reactive multiple species of contaminants making the source characterization process more challenging. To address this issue, a reactive transport simulation model PHT3D is linked to a Simulated Annealing based the optimum decision model. The numerical simulation model PHT3D is utilized for numerically simulating the reactive transport process involving multiple species in the former mine site area. The simulation results from the calibrated PHT3D model are illustrated, with and without incorporating the chemical reactions. These comparisons show the utility of using a reactive, geochemical transport process’ simulation model. Performance evaluation of the linked simulation optimization methodology is evaluated for a contamination scenario in a former mine site in Queensland, Australia. These performance evaluation results illustrate the applicability of linked simulation optimization model to identify the source characteristics while using PHT3D as a numerical reactive chemical species’ transport simulation model for the hydro-geochemically complex aquifer study area.
文摘A major challenge of any optimization problem is to find the global optimum solution. In a multi-dimensional solution space which is highly non-linear, often the optimization algorithm gets trapped around some local optima. Optimal Identification of unknown groundwater pollution sources poses similar challenges. Optimization based methodology is often applied to identify the unknown source characteristics such as location and flux release history over time, in a polluted aquifer. Optimization based models for identification of these characteristics of unknown ground-water pollution sources rely on comparing the simulated effects of candidate solutions to the observed effects in terms of pollutant concentration at specified sparse spatiotemporal locations. The optimization model minimizes the difference between the observed pollutant concentration measurements and simulated pollutant concentration measurements. This essentially constitutes the objective function of the optimization model. However, the mathematical formulation of the objective function can significantly affect the accuracy of the results by altering the response contour of the solution space. In this study, two separate mathematical formulations of the objective function are compared for accuracy, by incorporating different scenarios of unknown groundwater pollution source identification problem. Simulated Annealing (SA) is used as the solution algorithm for the optimization model. Different mathematical formulations of the objective function for minimizing the difference between the observed and simulated pollutant concentration measurements show different levels of accuracy in source identification results. These evaluation results demonstrate the impact of objective function formulation on the optimal identification, and provide a basis for choosing an appropriate mathematical formulation for unknown pollution source identification in contaminated aquifers.
基金Supported by the Research Foundation of Education Bureau of Jiangxi Province of China under Grant No.GJJ13459the National Natural Science Foundation of China under Grant No.11101350
文摘In the paper, Ablowitz–Ladik hierarchy with new self-consistent sources is investigated. First the source in the hierarchy is described as φnφn+1, where φnis related to the Ablowitz–Ladik spectral problem, instead of the corresponding adjoint spectral problem. Then by means of the inverse scattering transform, the multi-soliton solutions for the hierarchy are obtained. Two reductions to the discrete mKdV and nonlinear Schr¨odinger hierarchies with selfconsistent sources are considered by using the uniqueness of the Jost functions, as well as their N-soliton solutions.
文摘39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.ArcGIS inverse distance weight difference method was used to analyze the characteristics of pollution distribution,and single-factor pollution index,Nemerow comprehensive pollution index,ground accumulation index,and potential ecological risk index were selected to evaluate the characteristics of heavy metal pollution.Based on correlation analysis,the absolute principal component-multiple linear regression(APCS-MLR)and positive definite matrix factorization(PMF)models were used to analyze the sources of soil heavy metals.The results showed that the average concentrations of all eight heavy metals exceeded both national and Guangxi soil background values.Hg,Cd,and Zn exhibited high variation(greater than 0.5),indicating significant external disturbances,and their spatial distribution was closely related to mining activity locations.The single-factor pollution index evaluation indicated varying degrees of pollution risk for Cd,Zn,and As,with Cd and Zn being the most severe pollutants,as 69.23%and 30.77%of the samples fell into the moderate pollution or higher category.The geoaccumulation index analysis ranked the mean pollution levels of the eight elements as follows:Zn>Cd>Ni>Pb>Cu>Cr>Hg>As,with Cd and Zn showing the most severe contamination,and 51.28%of the samples exhibiting moderate or higher pollution levels.The Nemerow comprehensive pollution index evaluation showed that 74.35%of soil samples were classified as moderate to heavy pollution.The potential ecological risk index assessment indicated significant ecological risks posed by Cd and Zn,with 82.05%and 5.12%of the samples classified as causing strong to extreme ecological risks,respectively.The source apportionment analysis revealed minor differences between the two models.The APCS-MLR model identified three pollution sources and their contribution rates:anthropogenic mining sources(31.13%),parent material sources(40.38%),and unidentified sources(28.49%).The PMF model identified three pollution sources with contribution rates of anthropogenic mining sources(26.10%),parent material sources(46.96%),and a combined traffic and agricultural source(26.61%).Pb,Hg,Cd,and Zn mainly originated from mining activities;Cr,As,and Ni were primarily derived from the parent material,while Cu was predominantly attributed to traffic and agricultural sources.These findings provide a scientific basis for the prevention and control of heavy metal pollution in mining areas.
文摘A wide range of welding and surface treatment processes involve the use of a heat source which is moving at a constant speed over the component. The numerical simulation of such processes implies a transient analysis using a very refined mesh in order to follow properly the path of the heat source. The 3D-mesh size can be very large if one consider the welds length or the heat-treated surface size in industrial components. To reduce the computational time to acceptable values, several techniques have been investigated. The first type is to use analytical methods such as Rosenthal equations. The second type of solutions consists in performing a transient analysis using adaptive meshing. But, for a large proportion of the involved processes, practical experience demonstrates the existence of quasi steady state conditions over the major part of the heat source path. Numerical algorithms have therefore been developed to directly compute the steady temperature, metallurgical phase proportion and stress distributions. This paper gives a general overview of the different numerical methods used to simulate welding and surface treatment processes with a special emphasis on the steady state calculation. The benefits and limitations of each of them are discussed and applications are presented.
基金supported by the National Natural Science Foundation of China(42230513)the Research Project on Ecological Protection and High-Quality Development in the Yellow River Basin,China(2022-YRUC-01-0101)the Natural Science Basic Research Plan in Shaanxi Province,China(2022JC-LHJJ-11).
文摘Per-and poly-fluoroalkyl substances(PFAS)have garnered significant global attention due to their widespread presence and potential environmental and health risks.However,research on the occurrence and environmental behavior of PFAS across different media remains limited.We analyzed the occurrence,distribution,sources,and ecological risks of 32 PFAS across multiple media in the Weihe River,China.The concentrations of PFAS ranged from 5.89 to 472.84 ng/L in the pore water and from 9.93 to 459.50 ng/L in surface water,exhibiting significant spatial variability(P<0.05).In contrast,the PFAS concentration range in the sediments was 0.74-1.81 ng/g dry weight,with no pronounced spatial variation in solid-phase PFAS(P>0.05).Vertically,concentrations in 33.00%of pore water samples exceeded those in surface water,showing a heterogeneous vertical distribution with enrichment at depths of 40-60 cm.The physical-chemical characteristics of PFAS and the hydrological and sedimentary processes at the basin scale were responsible for PFAS partitioning between the aquatic environment and sediments.Four major sources were identified through integrated source apportionment:industrial and domestic wastewater(58.25%),aqueous film-forming foam(18.07%),combined input from household pollution and metal plating(8.70%),and stormwater runoff and landfill leachate(14.98%).The ecological risk assessment revealed negligible risks from short-chain PFAS in surface water and pore water,whereas long-chain PFAS posed low to moderate ecological risks.Furthermore,the discharge of PFAS from the Weihe River to the Yellow River was estimated up to 708.20 kg/a.This study provides critical data informing strategies for mitigating PFAS pollution in rivers across typical arid and semi-arid areas of China.
基金supported by the National Natural Science Foundation of China(Nos.62171469,62071029)。
文摘The estimation of the Number of Sources(NoS)is a significant challenge in signal processing,particularly due to the impact of colored noise on the performance of NoS estimation.This paper proposes a Multidimensional Feature Network(MFNet)which is designed for NoS estimation by extracting features of the sampled received signals and Sampled Covariance Matrix(SCM).The MFNet treats the raw signal and the SCM as two different types of data,and is able to achieve NoS estimation under colored noise and imperfect array.MFNet employs the Gated Recurrent Unit(GRU)to capture sequential information from the original signal data and to construct the Pseudo Covariance Matrix(PCM).Subsequently,various dimensional features,including eigenvalues and the Gerschgorin disk radius,are extracted from both the PCM and SCM,which are then jointly input into the subsequent network.An overall accuracy of 82%can be achieved after network training.The ablation experimental results demonstrate the effectiveness of multiple inputs.And simulation results demonstrate that the proposed MFNet achieves higher estimation accuracy compared to existing algorithms and exhibits greater robustness against colored noise.
基金supported by the National Natural Science Foundation of China(52304098,52106092,42376215,52474105)Shenzhen Science and Technology Program(JCYJ20220818095605012,JCYJ20220530113011027)+5 种基金Guangdong Basic and Applied Basic Research Foundation(2022A1515110338,2023A1515012316,2023A1515012761,2025A1515010748)Research Team Cultivation Program of Shenzhen University(2023QNT004)Shenzhen Key Laboratory of Natural Gas Hydrates(ZDSYS20200421111201738)the General Research Fund(No.12616222)Early Career Scheme(No.22611624)of Hong Kong Research Grants CouncilMajor Science and Technology Infrastructure Project of Material Genome Big–science Facilities Platform supported by the Municipal Development and Reform Commission of Shenzhen。
文摘Carbon Capture,Utilization,and Storage(CCUS)technology has gained widespread attention in recent years as a critical strategy to combat global climate change,particularly in achieving carbon neutrality goals.The Guangdong-Hong Kong-Macao Greater Bay Area(GBA),as one of China's most economically active regions,serves as a key engine for economic growth while also facing considerable carbon emission challenges.This study analyzes the industrial emission volume and geographical distribution of key emitting enterprises in the GBA,summarizes their technological processes and main carbonemitting equipment,and provides scientific support for precise mitigation policies and low-carbon development.Based on data from 176 key emitting enterprises,the study reveals that Guangzhou and Dongguan host the largest number of such enterprises.Carbon emissions are primarily concentrated in the power sector,dominated by coal-and gas-fired power units,characterized by significant spatial dispersion and uneven distribution.Beyond the power sector,the paper industry has a high number of enterprises but lower emissions.Key facilities such as boilers,cogeneration systems,and production lines are predominantly located near tributaries rivers in Dongguan and Jiangmen.The building materials sector,primarily cement production,ranks as the second-largest emitter,with hightemperature kilns and grinding equipment,particularly rotary kilns and glass furnaces,as the main sources.The petrochemical and chemical sectors have fewer enterprises and lower emissions in the GBA,mainly located in suburban industrial clusters.Carbon emissions in the GBA exhibit distinct industry concentration and geographical distribution disparities.This study provides crucial data and theoretical insights for the development of targeted emission reduction strategies,optimization of source-sink matching,and the advancement of CCUS technologies in the region,particularly from the GBA to the northern South China Sea.
文摘Rhodobacter sphaeroides is a purple non-sulfur bacterium that belongs to the α-3 subdivision of Proteobacteria. R. sphaeroides is a model bacterial species because of its complex genome structure and expanded metabolic capabilities. The genome of R. sphaeroides consists of two circular chromosomes and five endogenous plasmids. It has the ability to grow under a wide variety of environmental conditions. It grows aerobically (~20% O2), semi-aerobically (~2% O2), and photosynthetically (under anaerobic condition plus light). It has been previously shown that many bacterial species utilize a number of alternate carbon sources for their optimal growth under a variety of growth conditions. We hypothesize that different or an additional carbon source in the minimal medium differentially affects the bacterial growth under dark-aerobic conditions. The bacterial growth kinetics and the number of cells in the bacterial culture were analyzed by measuring the optical density (OD at 600 nm) and the colony forming units (CFUs) at regular intervals of bacterial cultures. Results reveal that sodium succinate is the preferred sole carbon source for the optimal growth of R. sphaeroides. The results of growth kinetics and CFUs together concluded that from the tested carbon sources, sodium succinate is the best single carbon source in the minimal media for the optimal growth of R. sphaeroides. Interestingly, cell culture grown in SIS supplemented with sodium acetate exhibits a prolonged lag phase with the lowest ODs and CFUs that later switches to the growth-burst phase support previously discovered similar phenomenon of the growth-rate switch in the presence of acetate metabolism. Future work will utilize the aerobically grown R. sphaeroides’ cells as a biocatalyst to deplete the oxygen levels from natural gas streams and industrial gas pipelines.
文摘In this study, the daily observational precipitation data and NCEP reanalysis data during 1951e2014, Euler and Lagrangian method were used to investigate the moisture sources of summer extreme precipitation events in North Xinjiang. The results show that water vapor at low and upper levels of most summer heavy rain (more than 50 mm d1 and less than 100 mm d1) in North Xinjiang are mainly transported by westerly circulation from the North Atlantic Ocean and the Eurasian continent. However, rainstorms of more than 100 mm d1, which are rarely observed, are dominated by vertically integrated moisture from the North Atlantic, Arctic Oceans, and the Eurasian continent, in addition to lowlevel moisture from the Indian Ocean. Among these sources, the anomalous low-level moisture from the Indian Ocean, which is closely associated with stronger meridional circulation, is considered to be more important with respect to rainstorms. On the days prior to rainstorm days, stronger meridional circulation leads to an anomalous pressure gradient force, which can transport low-level moisture from the Indian Ocean along the eastern periphery of the Tibetan Plateau to North Xinjiang. Furthermore, moisture from the North Atlantic, Arctic Oceans, the Eurasian continent, and the Indian Ocean converge together to influence rainstorm development in this region.
基金supported by the National Key R&D Program under Grant No.2021YFA1400500the National Natural Science Foundation of China under Grant No.22273029+1 种基金the New Cornerstone Science Foundation through the New Cornerstone Investigator Program under Grant No.NCI202303 and the XPLORER PRIZEthe Beijing Outstanding Young Scientist Program under Grant No.JWZQ20240101002。
文摘Ultrafast electron sources, which enable high spatiotemporal resolution in time-resolved electron microscopy and scanning probe microscopy, are receiving increased attention. The most widely used method for achieving ultrafast electron sources involves irradiating metal tips by ultrashort laser pulses, causing electron beam emission via the photoelectric effect [including photon-driven(quantum) or field-driven(classical) emission]. However, the thermionic electrons emission process due to the heating effect of ultrashort lasers, particularly its dynamic aspects, has rarely been addressed in previous studies. In this paper, we improved the signal-to-noise ratio of a two-pulse correlation measurement on the tip electron emission by nearly two orders of magnitude using a delay time modulation method. This allowed us to obtain information on the temperature evolution of hot electrons and phonons in a non-equilibrium state, and to extract characteristic time scales for electron-phonon and phonon-phonon scattering. Our findings indicate that the thermionic electrons emission, unlike the instantaneous photoelectric effect, causes electron emission to lag behind the laser pulse by tens of picoseconds, thus significantly affecting the detection of ultrafast dynamics of samples. Furthermore, such a lagging effect was found to be sensitive to the local structure of the metal tip, offering new insights into the improved design of ultrafast electron sources.
