This article presents a new synergistic extraction system composed of Cyanex 272(C272,bis(2,4,4-trimethylpentyl)phosphinic acid)and iso-octanol for Sc_(3+) separation.The proposed synergistic system possessed an Sc^(3...This article presents a new synergistic extraction system composed of Cyanex 272(C272,bis(2,4,4-trimethylpentyl)phosphinic acid)and iso-octanol for Sc_(3+) separation.The proposed synergistic system possessed an Sc^(3+) extraction efficiency of 93.5%and a back-extraction efficiency of 82.7%,with selectivity coefficients of β_(Sc/Fe)=459 and β_(Sc/Al)=4241,which are considerably higher as compared to the current extraction systems.The extraction mechanism was studied and interpreted.The enhanced extraction efficiency is attributed to the increased hydrophobicity of the ternary complex,whereas the back-extraction efficiency can be ascribed to the attenuated stability of the complex.C272 and C272–iso-octanol systems also possess considerable surface activity,which is beneficial for the phase separation in solvent extraction.Based on the solvent extraction results,a preliminary study was conducted on polymer inclusion membranes(PIMs)using the binary system for Sc^(3+) separation to avoid the formation of the third phase,achieving an optimal initial flux of PIM of 6.71×10^(−4)mol·m^(−2)·h^(−1).Our results provide valuable information on highly efficient Sc^(3+) separation,and the study on PIM extraction has shown a green alternative to solvent extraction.展开更多
Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti...Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.展开更多
The Northern Da Xing'anling Mountains are an important ecological barrier in China and are highly sensitive to global climate change.Gaining an in-depth understanding of the climate change characteristics in this ...The Northern Da Xing'anling Mountains are an important ecological barrier in China and are highly sensitive to global climate change.Gaining an in-depth understanding of the climate change characteristics in this highlatitude,cold region is crucial for protecting ecological security and responding to global climate change.This paper uses precipitation and average temperature data from 1980 to 2019,and applies methods such as wavelet analysis,cross-wavelet transform,wavelet coherence,and singular value decomposition(SVD)with heterogeneous correlation to study the climate change in the Northern Da Xing'anling Mountains over the past 40 years and its response to the El Ni?o phenomenon.The results show that:(1)The temperature in the Northern Da Xing'anling Mountains has shown a significant increasing trend,with a temperature trend rate of 0.30℃/10a(p<0.01).Spatially,the annual average temperature and temperature change rate exhibit latitudinal zonality,with the highest temperature occurring near the Zhalantun station in the southeastern part of the Northern Da Xing'anling Mountains,and the greatest temperature change rate observed near Xiao'ergou.The annual precipitation in the Northern Da Xing'anling Mountains ranges from 250 to 650 mm,with no obvious trend in precipitation variation.Overall,there is a decreasing trend,with a precipitation trend rate of-5.09 mm/10a(p>0.01).Precipitation shows a gradual decrease from east to west,and the spatial distribution of the precipitation trend rate is consistent with the trend in precipitation change.(2)Morlet wavelet analysis shows that the annual average temperature in the Northern Da Xing'anling Mountains exhibits scale variations of 21 years and 8years at the 40-year scale,while annual precipitation shows no obvious periodic characteristics.(3)The heterogeneous correlation chart in singular value decomposition indicates that the climate in the Northern Da Xing'anling Mountains is significantly influenced by the El Ni?o phenomenon.Among them,the temperature in XinBaragLeft Banner,Right Banner,and Manzhouli,as well as the southwestern area of Zhalantun,shows a strong response to El Ni?o events,while precipitation is notably affected in areas near Mohe,Tahe,Huzhong,and Xinlin.(4)According to the cross-wavelet and wavelet coherence analysis,the sea surface temperature in the Nino3.4region exhibits significant resonance with the temperature in the Northern Da Xing'anling Mountains at 10-17months and 18-62 months cycles,and there is a correlation between precipitation and temperature at different time periods and cyclical scales.展开更多
Significant progress has been made in exploring shale gas resources in the middle-upper Permian strata of western Hubei.However,the unclear geochemical characteristics and origins of the gas have hindered a comprehens...Significant progress has been made in exploring shale gas resources in the middle-upper Permian strata of western Hubei.However,the unclear geochemical characteristics and origins of the gas have hindered a comprehensive understanding of reservoir evolution and have constrained integrated resource development.This study involved a 28-h desorption experiment in which gases released from shales of the Dalong and Gufeng Formations were systematically collected for compositional and carbon—hydrogen isotope analyses.Comparing the compositional and geochemical characteristics of the desorbed gases and investigating their genetic origins resulted in four main findings:(1)Gas composition during the middle stage of desorption,excluding H_(2)S,best represents the original reservoir fluid,with component variations linked to adsorption and diffusion capacities.(2)Both shales display similar gas compositions with trace H_(2)S;the Dalong shale contains lower CH_(4),CO_(2),and H_(2)S but higher C_(2)H_(6)and N_(2).(3)Carbon and hydrogen isotopes indicate oil-type thermogenic gases,with carbon isotope reversal reflecting tectonic uplift,depressurization,and the mixing of primary kerogen-derived and secondary oil-/condensate-derived gases.(4)N_(2)likely originates from ammonium-bearing silicate decomposition,CO_(2)is mainly inorganic,from thermal carbonate decomposition with minor organic contribution,and H_(2)S may result from oil cracking or thermochemical sulfate reduction.This study provides a comprehensive record of the fluid characteristics of middle-upper Permian shale gas reservoirs and enhances the understanding of their formation and evolution.展开更多
Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the“air pollution complex”was first proposed by Professor Xiaoyan TANG in 1997.For papers published in 2021 ...Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the“air pollution complex”was first proposed by Professor Xiaoyan TANG in 1997.For papers published in 2021 on air pollution(only papers included in the Web of Science Core Collection database were considered),more than 24000 papers were authored or co-authored by scientists working in China.In this paper,we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years,including studies on(1)sources and emission inventories,(2)atmospheric chemical processes,(3)interactions of air pollution with meteorology,weather and climate,(4)interactions between the biosphere and atmosphere,and(5)data assimilation.The intention was not to provide a complete review of all progress made in the last few years,but rather to serve as a starting point for learning more about atmospheric chemistry research in China.The advances reviewed in this paper have enabled a theoretical framework for the air pollution complex to be established,provided robust scientific support to highly successful air pollution control policies in China,and created great opportunities in education,training,and career development for many graduate students and young scientists.This paper further highlights that developing and low-income countries that are heavily affected by air pollution can benefit from these research advances,whilst at the same time acknowledging that many challenges and opportunities still remain in atmospheric chemistry research in China,to hopefully be addressed over the next few decades.展开更多
Although many studies relevant to snow cover and permafrost have focused on alpine, arctic, and subarctic areas, there is still a lack of understanding of the influences of seasonal snow cover on the thermal regime of...Although many studies relevant to snow cover and permafrost have focused on alpine, arctic, and subarctic areas, there is still a lack of understanding of the influences of seasonal snow cover on the thermal regime of the soils in permafrost regions in the mid-latitudes and boreal regions, such as that on the westem flank of the Da Xing＇anling （Hinggan） Mountains, northeastern China. This paper gives a detailed analysis on meteorological data series from 2001 to 2010 provided by the Gen＇he Weather Station, which is located in a talik of discontinuous permafrost zone and with sparse meadow on the observation field. It is inferred that snow cover is important for the ground thermal regime in the middle Da Xing＇anling Mountains. Snow cover of 10-cm in thickness and five to six months in duration （generally November to next March） can reduce the heat loss from the ground to the atmosphere by 28%, and by 71% if the snow depth increases to 36 cm. Moreover, the occurrence of snow cover resulted in mean annual ground surface temperatures 4.7-8.2℃ higher than the mean annual air temperatures recorded at the Gen＇he Weather Station, The beginning date for stable snow cover establishment （SE date） and the initial snow depth （SDi） also had a great influences on the ground freezing process. Heavy snowfall before ground surface freeze-up could postpone and retard the freezing process in Gen＇he. As a result, the duration of ground freezing was shortened by at least 20 days and the maximum depth of frost penetration was as much as 90 cm shallower.展开更多
Quality-controlled and serially complete daily air temperature data are essential to evaluating and modelling the influences of climate change on the permafrost in cold regions. Due to malfunctions and location chang...Quality-controlled and serially complete daily air temperature data are essential to evaluating and modelling the influences of climate change on the permafrost in cold regions. Due to malfunctions and location changes of observing stations, temporal gaps （i.e., missing data） are common in collected datasets. The objective of this study was to assess the efficacy of Kriging spatial interpolation for estimating missing data to fill the temporal gaps in daily air temperature data in northeast China. A cross-validation experiment was conducted. Daily air temperature series from 1960 to 2012 at each station were estimated by using the universal Kriging （UK） and Kriging with an external drift （KED）, as appropriate, as if all the ob-servations at a given station were completely missing. The temporal and spatial variation patterns of estimation uncertainties were also checked. Results showed that Kriging spatial interpolation was generally desirable for estimating missing data in daily air temperature, and in this study KED performed slightly better than UK. At most stations the correlation coefficients （R2） between the observed and estimated daily series were 〉0.98, and root mean square errors （RMSEs） of the estimated daily mean （Tmean）, maximum （Tmax）, and minimum （Tmin） of air temperature were 〈3 ℃. However, the estimation quality was strongly affected by seasonality and had spatial variation. In general, estimation uncertainties were small in summer and large in winter. On average, the RMSE in winter was approximately 1 ℃ higher than that in summer. In addition, estimation uncertainties in mountainous areas with complex terrain were significantly larger than those in plain areas.展开更多
Forest canopy in a deciduous forest has significant sheltering effects on the sub-canopy solar radiation,significantly influencing the energy balance of snow and permafrost beneath the forest and their spatial distrib...Forest canopy in a deciduous forest has significant sheltering effects on the sub-canopy solar radiation,significantly influencing the energy balance of snow and permafrost beneath the forest and their spatial distribution.This study employs a digital camera mounted with a fisheye lens to acquire photographs at various times in a growth cycle of the forest canopy at three selected sites in a deciduous forest near the Greater Khingan Mountains Forest Ecological Station,Northeast China.The vegetation types and conditions at the selected sites include P1 in Ledum-Claopodium-L.dahurica,P2 in Carex tato-L.dahurica,and P3 in Betula fruticosa-L.dahurica.After necessary image processing,these photographs were used to identify the canopy structure and its impacts on the sub-canopy solar radiation.Results show that fisheye photographs can successfully capture the forest canopy structure and are useful in estimating the sub-canopy solar radiation.The order of sheltering effects from the largest to the smallest on sub-canopy solar radiation at three selected sites is P3,P1,and P2,highly depending on the canopy density.Then sub-canopy solar radiation was calculated using fisheye photographs and an algorithm validated by in-situ observed solar radiation beneath the canopy at P1 and P3.The results are reasonable,although the accuracy seems compromised due to the mismatch of conditions for calculation and observation.Results also show that the mean annual solar radiation above the canopy was about 148.3 W/m2 in 2018,and the mean annual solar radiation values beneath the canopy were about 90.0,123.8,and 61.0 W/m2 at P1,P2,and P3,with only 60%,84%,and 42%of the total solar radiation penetrating through the canopy,respectively.Even in winter,when the trees are leafless,the canopy sheltering effects cannot be ignored in dense forests.Despite the limitations,fisheye photographs and related algorithms are useful in investigating the forest canopy structure and its impacts on sub-canopy solar radiation.展开更多
The ground temperature and active layer are greatly influenced by vegetation in the Greater Hinggan Mountains in Northeastern China.However,vegetation,as a complex system,is difficult to separate the influence of its ...The ground temperature and active layer are greatly influenced by vegetation in the Greater Hinggan Mountains in Northeastern China.However,vegetation,as a complex system,is difficult to separate the influence of its different components on the ground thermal regime.In this paper,four vegetation types,including a Larix dahurica-Ledum palustre var.dilatatum-Bryum forest（P1）,a L.dahurica-Betula fruticosa forest（P2）,a L.dahurica-Carex tato forest（P3） in the China Forest Ecological Research Network Station in Genhe,and a Carex tato swamp（P4） at the permafrost observation site in Yitulihe,have been selected to study and compare their seasonal and annual influence on the ground thermal regime.Results show that the vegetation insulates the ground resulting in a relatively high ground temperature variability in the Carex tato swamp where there are no tree stands and shrubs when compared with three forested vegetation types present in the area.Vegetation thickness,structure,and coverage are the most important factors that determine the insulating properties of the vegetation.In particular,the growth of ground cover,its water-holding capacity and ability to intercept snow exert a significant effect on the degree of insulation of the soil under the same vegetation.展开更多
The era of open information in healthcare has arrived. E-healthcare supported by big data supports the move toward greater trans-parency in healthcare by making decades of stored health data searchable and usable. Thi...The era of open information in healthcare has arrived. E-healthcare supported by big data supports the move toward greater trans-parency in healthcare by making decades of stored health data searchable and usable. This paper gives an overview the e-health-care architecture. We discuss the four layers of the architecture-data collection, data transport, data storage, and data analysis-as well as the challenges of data security, data privacy, real-time delivery, and open standard interface. We discuss the necessity of establishing an impeccably secure access mechanism and of enacting strong laws to protect patient privacy.展开更多
Objective: To study the relationship between the expression of multidrug resistance-associated protein (MRP) gene in nasopharyngeal carcinoma (NPC) and the radiosensitivity of primary lesions of NPC. Methods: Total 51...Objective: To study the relationship between the expression of multidrug resistance-associated protein (MRP) gene in nasopharyngeal carcinoma (NPC) and the radiosensitivity of primary lesions of NPC. Methods: Total 51 cases of NPC were analyzed retrospectively, who were treated by radiotherapy between January 1, 1999 and December 31, 2000 in our department, including the cases of pure radiotherapy and chemotherapy after radiotherapy. Using immunohistochemiscal S-P method, the expression of MRP in NPC was detected, and the relationship with the radiosensitivity of primary lesions of NPC was analyzed. Results: The rate of positive expression was 68.63% (35/51) in NPC, and there were significant difference between T stages (P<0.05), but no significant difference with radiosensitivity of primary lesions of NPC (P>0.05). Conclusion: There is a higher expression of MRP in NPC, but it has no relationship with radiosensitivity of primary lesions of NPC. So MRP can not be regarded as the predictive marker of radiosensitivity of primary lesions of NPC.展开更多
Ammonia(NH_(3))is a key precursor of fine particulate matter(PM_(2.5))in the air;however,its emission sources at different heights remain poorly understood in the Pearl River Delta(PRD)region of China.In this study,we...Ammonia(NH_(3))is a key precursor of fine particulate matter(PM_(2.5))in the air;however,its emission sources at different heights remain poorly understood in the Pearl River Delta(PRD)region of China.In this study,we simultaneously collected PM_(2.5)samples at three atmospheric heights(ground,118 m,and 488 m)based on the atmospheric observatories of Canton Tower,the tallest structure in the PRD region.Our results showed that the average NH_(4)+concentrations were 2.7±1.4,3.0±1.8,and 2.6±1.7μg/m3 at the ground site,118 m,and 488 m during the sampling campaign,with no significant difference(p>0.05)among the three heights.However,the stable nitrogen isotope composition values in NH_(4)+(δ15N-NH_(4)+)displayed a significant correlation with height(p<0.05).We further calculated the initialδ15N-NH_(3)values and performed source apportionments using the Bayesian Isotope Mixture Model.The results indicated that the mean contributions of agriculture,waste,vehicle,biomass burning,NH_(3)slip,and coal combustion were 9.9%±4.4%,8.3%±5.5%,29%±8.0%,16%±2.2%,25%±6.0%,and 12%±3.4%,respectively,at the ground site during the sampling campaign.By contrast,the contributions of sources at 488 m remained relatively stable due to the limited influence of local activities.Overall,our study highlights the dominant role of combustion sources in NH_(3)emissions in the PRD region,with their contribution being highly dependent on atmospheric height.展开更多
Background：Autophagy has been found to be involved in animal and cell models ofatherosclerosis,but to date,it lacks general observation in human atherosclerotic plaques.Here,we investigated autophagy in smooth muscle...Background：Autophagy has been found to be involved in animal and cell models ofatherosclerosis,but to date,it lacks general observation in human atherosclerotic plaques.Here,we investigated autophagy in smooth muscle cells （SMCs）,endothelial cells （ECs）,and macrophages in human atherosclerotic plaques via transmission electron microscopy （TEM）,western blotting,and immunohistochemistry analysis.Methods：The histopathologic morphology of these plaques was observed via hematoxylin and eosin staining.The ultrastructural morphology of the SMCs,ECs,and macrophages in these plaques was observed via TEM.The localization ofmicrotubule-associated protein 1 light chain 3 （MAP 1-LC3）,a relatively special maker ofautophagy,in plaques was observed by double fluorescent immunochemistty and western blotting.Results：All of these human atherosclerotic plaques were considered advanced and unstable in histologically observation.By double fluorescent immunochemistry,the expression of LC3-Ⅱ increased in the SMCs of the fibrous cap,the macrophages,and the microvascular ECs of the plaque shoulders.The protein level of LC3-Ⅱ by western blotting significantly increased in plaques compared with normal controls.In addition,TEM observation of plaques revealed certain features of autophagy in SMCs,ECs,and macrophages including the formation of myelin figures,vacuolization,and the accumulation of inclusions in the cytosol.These results indicate that autophagy is activated in SMCs,ECs,and macrophages in human advanced atherosclerotic plaques.Conclusions：Our study is to demonstrate the existence of autophagy in human atherosclerotic plaques by different methods,which may contribute to the development of pharmacological approaches to stabilize vulnerable and rupture-prone lesions.展开更多
Agricultural sources and non-agricultural emissions contribute to gaseous ammonia(NH_(3))that plays a vital role in severe haze formation.Qualitative and quantitative contributions of these sources to ambient PM_(2.5)...Agricultural sources and non-agricultural emissions contribute to gaseous ammonia(NH_(3))that plays a vital role in severe haze formation.Qualitative and quantitative contributions of these sources to ambient PM_(2.5)(particulate matter with an aerodynamic equivalent diameter below 2.5µm)concentrations remains uncertain.Stable nitrogen isotopic composition(δ^(15)N)of NH_(3)and NH_(4)+(δ^(15)N(NH_(3))andδ^(15)N(NH_(4)+),respectively)can yield valuable information about its sources and associated processes.This review provides an overview of the recent progress in analytical techniques forδ^(15)N(NH_(3))andδ^(15)N(NH_(4)+)measurement,sampling of atmospheric NH_(3)and NH_(4)+in the ambient air and their sources signature(e.g.,agricultural vs.fossil fuel),and isotope-based source apportionment of NH_(3)in urban atmosphere.This study highlights that collecting sample that are fully representative of emission sources remains a challenge in fingerprintingδ^(15)N(NH_(3))values of NH_(3)emission sources.Furthermore,isotopic fractionation during NH_(3)gas-to-particle conversion under varying ambient field conditions(e.g.,relative humidity,particle pH,temperature)remains unclear,which indicates more field and laboratory studies to validate theoretically predicted isotopic fractionation are required.Thus,this study concludes that lack of refinedδ^(15)N(NH_(3))fingerprints and full understanding of isotopic fractionation during aerosol formation in a laboratory and field conditions is a limitation for isotope-based source apportionment of NH_(3).More experimental work(in chamber studies)and theoretical estimations in combinations of field verification are necessary in characterizing isotopic fractionation under various environmental and atmospheric neutralization conditions,which would help to better interpret isotopic data and our understanding on NH_(x)(NH_(3)+NH_(4)+)dynamics in the atmosphere.展开更多
Aerosol ammonium(NH_(4)^(+)),mainly produced from the reactions of ammonia(NH_(3))with acids in the atmosphere,has significant impacts on air pollution,radiative forcing,and human health.Understanding the source and f...Aerosol ammonium(NH_(4)^(+)),mainly produced from the reactions of ammonia(NH_(3))with acids in the atmosphere,has significant impacts on air pollution,radiative forcing,and human health.Understanding the source and formation mechanism of NH_(4)^(+)can provide scientific insights into air quality improvements.However,the sources of NH_(3)in urban areas are not well understood,and few studies focus on NH_(3)/NH_(4)^(+)at different heights within the atmospheric boundary layer,which hinders a comprehensive understanding of aerosol NH_(4)^(+).In this study,we perform both field observation and modeling studies(the Community Multiscale Air Quality,CMAQ)to investigate regional NH_(3)emission sources and vertically resolved NH_(4)^(+)formation mechanisms during the winter in Beijing.Both stable nitrogen isotope analyses and CMAQ model suggest that combustion-related NH_(3)emissions,including fossil fuel sources,NH_(3)slip,and biomass burning,are important sources of aerosol NH_(4)^(+)with more than 60%contribution occurring on heavily polluted days.In contrast,volatilization-related NH_(3)sources(livestock breeding,N-fertilizer application,and human waste)are dominant on clean days.Combustion-related NH_(3)is mostly local from Beijing,and biomass burning is likely an important NH_(3)source(~15%–20%)that was previously overlooked.More effective control strategies such as the two-product(e.g.,reducing both SO_(2)and NH_(3))control policy should be considered to improve air quality.展开更多
The lower Cambrian Niutitang Formation is of crucial importance for shale gas target reservoirs in western Hubei,China;however,little work has been done in this field,and its shale gas accumulation and enrichment mech...The lower Cambrian Niutitang Formation is of crucial importance for shale gas target reservoirs in western Hubei,China;however,little work has been done in this field,and its shale gas accumulation and enrichment mechanism are still unclear.Based on survey wells,outcrop data,and large numbers of tests,the geological conditions of shale gas accumulation were studied;moreover,the factors that influence the gas content were thoroughly discussed.The results show that the Niutitang Formation(Є1n)can be divided into three sections:the first section(Є_(1)n^(1)),the second section(Є_(1)n^(2)),and the third section(Є1n3).TheЄ_(1)n^(2) is the main shale gas reservoir.The deep shelf facies is the main sedimentary facies and can be divided into three main lithofacies:argillaceous siltstone,carbonaceous shale and carbonaceous siliceous rock.The total organic carbon(TOC)content shows gentle growth trends until bottom of theЄ_(1)n^(2) and then decreases rapidly within theЄ_(1)n^(1),and the TOC content mainly ranges from 2%to 4%horizontally.The calcite and dolomite dissolution pores,clay intergranular pores and organic pores are the main pore types and the micropore types are clearly related to the mineral compositions and the TOC content.Vertically,the gas content is mainly affected by the TOC content.Horizontally,wells with high gas contents are distributed only southeast of the Huangling anticline,and the combination of structural styles,fault and fracture development,and the distribution of the regional unconformity boundary between the upper Sinian Dengying Formation(Z2d)and theЄ_(1)n^(2) are the three most important factors affecting the gas content.The favorable areas must meet the following conditions:a deep shelf environment,the presence of theЄ_(1)n^(1),wide and gentle folds,far from large normal faults that are more than 5 km,moderate thermal evolution,and greater than 500 m burial depth;this includes the block with the YD2–ZD2 wells,and the block with the Y1 and YD4 wells,which are distributed in the southern portion of the Huangling anticline and northern portion of the Xiannvshan fault.展开更多
In order to study the influence rule of various factors on the operating power consumption of the traction orchard transporter and realize the optimal design of the operation power consumption of the transporter,accor...In order to study the influence rule of various factors on the operating power consumption of the traction orchard transporter and realize the optimal design of the operation power consumption of the transporter,according to the traditional experience and the existing research foundation,the monorail transporter test bench was designed and built on the basis of the whole structure and operation characteristics of the transporter.Taking the motor frequency,track gradient and load as the investigation factors,and the driving shaft power,shaft power transmission and mechanical efficiency as the evaluation indices,the orthogonal test was conducted,and the range analysis of the influence effect was carried out according to the test results.The primary and secondary orders of the influence of various factors were obtained that motor frequency was greater than track gradient and track gradient was greater than load.According to the orthogonal test results,the second-order response surface method was used to establish the optimization model of the power consumption of the transporter,and the model was verified on the test bench.The results showed that the relative error between the model optimization value and the test value based on the response surface power optimization model was less than 10%,which indicated that the power optimization model had satisfactory performance.The research can provide a reference for the orchard conveyor to choose the parameter combination which can save power consumption and the motor that matches power consumption.展开更多
To solve the problems of the traditional orchard conveyor,such as inflexible steering,a complex structure,poor stability and no power grid coverage,a remote-controlled rail conveyor powered by hydraulic pressure for m...To solve the problems of the traditional orchard conveyor,such as inflexible steering,a complex structure,poor stability and no power grid coverage,a remote-controlled rail conveyor powered by hydraulic pressure for mountainous orchards was designed and manufactured.Climbing stress analysis was carried out on a full-load trailer to obtain the maximum traction force,which met the requirement of the climbing slope of the transport mechanism.The key components of the conveyor were developed,such as the hydraulic transmission,the control system,safety protection devices,limiting devices,the throttle and decompression actuator,the counterweight tension and the battery.Through the theoretical calculations of key components,an orchard conveyor powered by diesel and hydraulic pressure was designed.Finally,the working performance of the transporter was tested through functionality,driving speed,system pressure and remote-controlled tests.The test results showed that the climbing angle of the transporter can reach 50°,the uphill load can reach 840 kg,the downhill load can reach 1100 kg,and the average running speed is 0.77 m/s;the driving speed ranges from 0.29 m/s to 1.08 m/s,and the system pressure ranges from 3.2 MPa to 10 MPa.The driving speed and system pressure are significantly affected by the load,and the remote control distance can reach 455 m.The technical specifications of the transporter meet all the design requirements,and the problem of stable operation of the transporter without power grid coverage has been addressed.The research results can well meet the practical application requirements of mountain orchard transportation without power grid coverage and provide theoretical reference for the design of key components of mountain orchard transportation machinery.展开更多
Ionic liquids have been extensively studied as solvents or catalysts for oxidative desulfurization(ODS)of diesel fuel,but it is still a challenge to reduce the desulfurization time and steps.In this work,a new highly ...Ionic liquids have been extensively studied as solvents or catalysts for oxidative desulfurization(ODS)of diesel fuel,but it is still a challenge to reduce the desulfurization time and steps.In this work,a new highly efficient desulfurization system composed of CoFe_(2)O_(4) magnetic nanoparticle,[HMIM]Br-FeCl_(3) and H_(2)O_(2) was developed for the ODS of FCC diesel fuel.The desulfurization performances were investigated including desulfurization time,temperature,volume ratio of IL/oil,O/S molar ratio,dosage of CoFe_(2)O_(4),FeCl_(3) content in ILs,regeneration,and reuse of catalyst and solvent.Owing to the coupled catalytic roles of CoFe_(2)O_(4) magnetic nanoparticle and[HMIM]Br-FeCl_(3),where Co2t and Fe3t interact with H_(2)O_(2) to produce ·OH radical that converts S-compounds into sulfone and sulfoxide compounds,such a desulfurization system is highly effective in removing S-compound in diesel fuel.The S-content in FCC diesel fuel was reduced from the original 272.8 ppm to 0.5 ppm with 99.82%S-removal efficiency after one step within 8 minunder the optimal conditions of 25℃,8 min,V(IL/oil)=1:10,O/S=20,5 wt%CoFe_(2)O_(4) dosage and n([HMIM]Br)/n(FeCl_(3))=1:1;the desulfurization performance is much better in desulfurization time and steps than other desulfurization systems reported previously.The desulfurization system can be regenerated and reused without remarkable loss of desulfurization activity.A desulfurization mechanism was proposed.展开更多
基金support from the National Natural Science Foundation of China Regional Innovation and Development Joint Fund(U24A20557)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDC0230403)+3 种基金the National Natural Science Foundation of China(22378393,22208356)“Hundred Talents Program”of the Chinese Academy of Sciencesthe Chinese Academy of Sciences stably supports the youth team plan in the field of basic research(YSBR 038)Key Research&Development projects in Qinghai Province(2023-HZ-805).
文摘This article presents a new synergistic extraction system composed of Cyanex 272(C272,bis(2,4,4-trimethylpentyl)phosphinic acid)and iso-octanol for Sc_(3+) separation.The proposed synergistic system possessed an Sc^(3+) extraction efficiency of 93.5%and a back-extraction efficiency of 82.7%,with selectivity coefficients of β_(Sc/Fe)=459 and β_(Sc/Al)=4241,which are considerably higher as compared to the current extraction systems.The extraction mechanism was studied and interpreted.The enhanced extraction efficiency is attributed to the increased hydrophobicity of the ternary complex,whereas the back-extraction efficiency can be ascribed to the attenuated stability of the complex.C272 and C272–iso-octanol systems also possess considerable surface activity,which is beneficial for the phase separation in solvent extraction.Based on the solvent extraction results,a preliminary study was conducted on polymer inclusion membranes(PIMs)using the binary system for Sc^(3+) separation to avoid the formation of the third phase,achieving an optimal initial flux of PIM of 6.71×10^(−4)mol·m^(−2)·h^(−1).Our results provide valuable information on highly efficient Sc^(3+) separation,and the study on PIM extraction has shown a green alternative to solvent extraction.
基金the National Key R&D Program of China(No.2023YFB3210102).
文摘Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.41971059,41671079,and U20A2082)the Outstanding Youth Science Program of Hu'nan Provincial Education Department(Grant No.22B0517)。
文摘The Northern Da Xing'anling Mountains are an important ecological barrier in China and are highly sensitive to global climate change.Gaining an in-depth understanding of the climate change characteristics in this highlatitude,cold region is crucial for protecting ecological security and responding to global climate change.This paper uses precipitation and average temperature data from 1980 to 2019,and applies methods such as wavelet analysis,cross-wavelet transform,wavelet coherence,and singular value decomposition(SVD)with heterogeneous correlation to study the climate change in the Northern Da Xing'anling Mountains over the past 40 years and its response to the El Ni?o phenomenon.The results show that:(1)The temperature in the Northern Da Xing'anling Mountains has shown a significant increasing trend,with a temperature trend rate of 0.30℃/10a(p<0.01).Spatially,the annual average temperature and temperature change rate exhibit latitudinal zonality,with the highest temperature occurring near the Zhalantun station in the southeastern part of the Northern Da Xing'anling Mountains,and the greatest temperature change rate observed near Xiao'ergou.The annual precipitation in the Northern Da Xing'anling Mountains ranges from 250 to 650 mm,with no obvious trend in precipitation variation.Overall,there is a decreasing trend,with a precipitation trend rate of-5.09 mm/10a(p>0.01).Precipitation shows a gradual decrease from east to west,and the spatial distribution of the precipitation trend rate is consistent with the trend in precipitation change.(2)Morlet wavelet analysis shows that the annual average temperature in the Northern Da Xing'anling Mountains exhibits scale variations of 21 years and 8years at the 40-year scale,while annual precipitation shows no obvious periodic characteristics.(3)The heterogeneous correlation chart in singular value decomposition indicates that the climate in the Northern Da Xing'anling Mountains is significantly influenced by the El Ni?o phenomenon.Among them,the temperature in XinBaragLeft Banner,Right Banner,and Manzhouli,as well as the southwestern area of Zhalantun,shows a strong response to El Ni?o events,while precipitation is notably affected in areas near Mohe,Tahe,Huzhong,and Xinlin.(4)According to the cross-wavelet and wavelet coherence analysis,the sea surface temperature in the Nino3.4region exhibits significant resonance with the temperature in the Northern Da Xing'anling Mountains at 10-17months and 18-62 months cycles,and there is a correlation between precipitation and temperature at different time periods and cyclical scales.
基金supported by the Hubei Provincial Natural Science Foundation of China(Grant No.2022CFB490,2024AFD381)Science and Technology Project of Hubei Geological Bureau(Grant No.KJ2024-2,KJ2025-14)Open Fund of Technology Innovation Center for Shale oil and Gas Accumulation Theory and Engineering in Southern Complex Structural Area,China Geological Survey(Grant No.SOG-202410).
文摘Significant progress has been made in exploring shale gas resources in the middle-upper Permian strata of western Hubei.However,the unclear geochemical characteristics and origins of the gas have hindered a comprehensive understanding of reservoir evolution and have constrained integrated resource development.This study involved a 28-h desorption experiment in which gases released from shales of the Dalong and Gufeng Formations were systematically collected for compositional and carbon—hydrogen isotope analyses.Comparing the compositional and geochemical characteristics of the desorbed gases and investigating their genetic origins resulted in four main findings:(1)Gas composition during the middle stage of desorption,excluding H_(2)S,best represents the original reservoir fluid,with component variations linked to adsorption and diffusion capacities.(2)Both shales display similar gas compositions with trace H_(2)S;the Dalong shale contains lower CH_(4),CO_(2),and H_(2)S but higher C_(2)H_(6)and N_(2).(3)Carbon and hydrogen isotopes indicate oil-type thermogenic gases,with carbon isotope reversal reflecting tectonic uplift,depressurization,and the mixing of primary kerogen-derived and secondary oil-/condensate-derived gases.(4)N_(2)likely originates from ammonium-bearing silicate decomposition,CO_(2)is mainly inorganic,from thermal carbonate decomposition with minor organic contribution,and H_(2)S may result from oil cracking or thermochemical sulfate reduction.This study provides a comprehensive record of the fluid characteristics of middle-upper Permian shale gas reservoirs and enhances the understanding of their formation and evolution.
基金funded by the National Natural Science Foundation of China(Grant No.91844000)。
文摘Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the“air pollution complex”was first proposed by Professor Xiaoyan TANG in 1997.For papers published in 2021 on air pollution(only papers included in the Web of Science Core Collection database were considered),more than 24000 papers were authored or co-authored by scientists working in China.In this paper,we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years,including studies on(1)sources and emission inventories,(2)atmospheric chemical processes,(3)interactions of air pollution with meteorology,weather and climate,(4)interactions between the biosphere and atmosphere,and(5)data assimilation.The intention was not to provide a complete review of all progress made in the last few years,but rather to serve as a starting point for learning more about atmospheric chemistry research in China.The advances reviewed in this paper have enabled a theoretical framework for the air pollution complex to be established,provided robust scientific support to highly successful air pollution control policies in China,and created great opportunities in education,training,and career development for many graduate students and young scientists.This paper further highlights that developing and low-income countries that are heavily affected by air pollution can benefit from these research advances,whilst at the same time acknowledging that many challenges and opportunities still remain in atmospheric chemistry research in China,to hopefully be addressed over the next few decades.
基金supported by the National Natural Science Foundation of China (Nos. 41201066, 41401028, and J0930003/J0109)the State Key Laboratory of Frozen Soils Engineering (No. SKLFSE-ZT-14)
文摘Although many studies relevant to snow cover and permafrost have focused on alpine, arctic, and subarctic areas, there is still a lack of understanding of the influences of seasonal snow cover on the thermal regime of the soils in permafrost regions in the mid-latitudes and boreal regions, such as that on the westem flank of the Da Xing＇anling （Hinggan） Mountains, northeastern China. This paper gives a detailed analysis on meteorological data series from 2001 to 2010 provided by the Gen＇he Weather Station, which is located in a talik of discontinuous permafrost zone and with sparse meadow on the observation field. It is inferred that snow cover is important for the ground thermal regime in the middle Da Xing＇anling Mountains. Snow cover of 10-cm in thickness and five to six months in duration （generally November to next March） can reduce the heat loss from the ground to the atmosphere by 28%, and by 71% if the snow depth increases to 36 cm. Moreover, the occurrence of snow cover resulted in mean annual ground surface temperatures 4.7-8.2℃ higher than the mean annual air temperatures recorded at the Gen＇he Weather Station, The beginning date for stable snow cover establishment （SE date） and the initial snow depth （SDi） also had a great influences on the ground freezing process. Heavy snowfall before ground surface freeze-up could postpone and retard the freezing process in Gen＇he. As a result, the duration of ground freezing was shortened by at least 20 days and the maximum depth of frost penetration was as much as 90 cm shallower.
基金funded by the Chinese National Fund Projects (Nos. 41401028, 41201066)by the State Key Laboratory of Frozen Soils Engineering (Project No. SKLFSE201201)
文摘Quality-controlled and serially complete daily air temperature data are essential to evaluating and modelling the influences of climate change on the permafrost in cold regions. Due to malfunctions and location changes of observing stations, temporal gaps （i.e., missing data） are common in collected datasets. The objective of this study was to assess the efficacy of Kriging spatial interpolation for estimating missing data to fill the temporal gaps in daily air temperature data in northeast China. A cross-validation experiment was conducted. Daily air temperature series from 1960 to 2012 at each station were estimated by using the universal Kriging （UK） and Kriging with an external drift （KED）, as appropriate, as if all the ob-servations at a given station were completely missing. The temporal and spatial variation patterns of estimation uncertainties were also checked. Results showed that Kriging spatial interpolation was generally desirable for estimating missing data in daily air temperature, and in this study KED performed slightly better than UK. At most stations the correlation coefficients （R2） between the observed and estimated daily series were 〉0.98, and root mean square errors （RMSEs） of the estimated daily mean （Tmean）, maximum （Tmax）, and minimum （Tmin） of air temperature were 〈3 ℃. However, the estimation quality was strongly affected by seasonality and had spatial variation. In general, estimation uncertainties were small in summer and large in winter. On average, the RMSE in winter was approximately 1 ℃ higher than that in summer. In addition, estimation uncertainties in mountainous areas with complex terrain were significantly larger than those in plain areas.
基金the National Natural Science Foundation of China(Grant Nos.41971079 and 41671059,41975081).
文摘Forest canopy in a deciduous forest has significant sheltering effects on the sub-canopy solar radiation,significantly influencing the energy balance of snow and permafrost beneath the forest and their spatial distribution.This study employs a digital camera mounted with a fisheye lens to acquire photographs at various times in a growth cycle of the forest canopy at three selected sites in a deciduous forest near the Greater Khingan Mountains Forest Ecological Station,Northeast China.The vegetation types and conditions at the selected sites include P1 in Ledum-Claopodium-L.dahurica,P2 in Carex tato-L.dahurica,and P3 in Betula fruticosa-L.dahurica.After necessary image processing,these photographs were used to identify the canopy structure and its impacts on the sub-canopy solar radiation.Results show that fisheye photographs can successfully capture the forest canopy structure and are useful in estimating the sub-canopy solar radiation.The order of sheltering effects from the largest to the smallest on sub-canopy solar radiation at three selected sites is P3,P1,and P2,highly depending on the canopy density.Then sub-canopy solar radiation was calculated using fisheye photographs and an algorithm validated by in-situ observed solar radiation beneath the canopy at P1 and P3.The results are reasonable,although the accuracy seems compromised due to the mismatch of conditions for calculation and observation.Results also show that the mean annual solar radiation above the canopy was about 148.3 W/m2 in 2018,and the mean annual solar radiation values beneath the canopy were about 90.0,123.8,and 61.0 W/m2 at P1,P2,and P3,with only 60%,84%,and 42%of the total solar radiation penetrating through the canopy,respectively.Even in winter,when the trees are leafless,the canopy sheltering effects cannot be ignored in dense forests.Despite the limitations,fisheye photographs and related algorithms are useful in investigating the forest canopy structure and its impacts on sub-canopy solar radiation.
基金supported by the Open Fund of the State Key Laboratory of Frozen Soils Engineering (Grant No.SKLFSE200902,SKLFSE-ZT-14 and SKLFSE-ZT-12)National Natural Science Foundation of China (Grant Nos.41201066 and J0930003/ J0109)
文摘The ground temperature and active layer are greatly influenced by vegetation in the Greater Hinggan Mountains in Northeastern China.However,vegetation,as a complex system,is difficult to separate the influence of its different components on the ground thermal regime.In this paper,four vegetation types,including a Larix dahurica-Ledum palustre var.dilatatum-Bryum forest（P1）,a L.dahurica-Betula fruticosa forest（P2）,a L.dahurica-Carex tato forest（P3） in the China Forest Ecological Research Network Station in Genhe,and a Carex tato swamp（P4） at the permafrost observation site in Yitulihe,have been selected to study and compare their seasonal and annual influence on the ground thermal regime.Results show that the vegetation insulates the ground resulting in a relatively high ground temperature variability in the Carex tato swamp where there are no tree stands and shrubs when compared with three forested vegetation types present in the area.Vegetation thickness,structure,and coverage are the most important factors that determine the insulating properties of the vegetation.In particular,the growth of ground cover,its water-holding capacity and ability to intercept snow exert a significant effect on the degree of insulation of the soil under the same vegetation.
基金the Natural Science Foundation of Guangdong Province, China (No.9151009001000021)the Ministry of Education of Guangdong Province Special Fund Funded Projects through the Cooperative of China (No.2009B090300341)+2 种基金the National Natural Science Foundation of China (No.61262013)the Open Fund of Guangdong Province Key Laboratory of Precision Equipment and Manufacturing Technology (No.PEMT1303)the Higher Vocational Education Teaching Reform Project of Guangdong Province (No.20130301011) for their support in this research
文摘The era of open information in healthcare has arrived. E-healthcare supported by big data supports the move toward greater trans-parency in healthcare by making decades of stored health data searchable and usable. This paper gives an overview the e-health-care architecture. We discuss the four layers of the architecture-data collection, data transport, data storage, and data analysis-as well as the challenges of data security, data privacy, real-time delivery, and open standard interface. We discuss the necessity of establishing an impeccably secure access mechanism and of enacting strong laws to protect patient privacy.
文摘Objective: To study the relationship between the expression of multidrug resistance-associated protein (MRP) gene in nasopharyngeal carcinoma (NPC) and the radiosensitivity of primary lesions of NPC. Methods: Total 51 cases of NPC were analyzed retrospectively, who were treated by radiotherapy between January 1, 1999 and December 31, 2000 in our department, including the cases of pure radiotherapy and chemotherapy after radiotherapy. Using immunohistochemiscal S-P method, the expression of MRP in NPC was detected, and the relationship with the radiosensitivity of primary lesions of NPC was analyzed. Results: The rate of positive expression was 68.63% (35/51) in NPC, and there were significant difference between T stages (P<0.05), but no significant difference with radiosensitivity of primary lesions of NPC (P>0.05). Conclusion: There is a higher expression of MRP in NPC, but it has no relationship with radiosensitivity of primary lesions of NPC. So MRP can not be regarded as the predictive marker of radiosensitivity of primary lesions of NPC.
基金supported by the National Natural Science Foundation of China(No.42230602)the National Key Research and Development Program of China(No.2022YFC3700602)the Guang Dong Basic and Applied Basic Research Foundation(China)(No.2024B1515040026).
文摘Ammonia(NH_(3))is a key precursor of fine particulate matter(PM_(2.5))in the air;however,its emission sources at different heights remain poorly understood in the Pearl River Delta(PRD)region of China.In this study,we simultaneously collected PM_(2.5)samples at three atmospheric heights(ground,118 m,and 488 m)based on the atmospheric observatories of Canton Tower,the tallest structure in the PRD region.Our results showed that the average NH_(4)+concentrations were 2.7±1.4,3.0±1.8,and 2.6±1.7μg/m3 at the ground site,118 m,and 488 m during the sampling campaign,with no significant difference(p>0.05)among the three heights.However,the stable nitrogen isotope composition values in NH_(4)+(δ15N-NH_(4)+)displayed a significant correlation with height(p<0.05).We further calculated the initialδ15N-NH_(3)values and performed source apportionments using the Bayesian Isotope Mixture Model.The results indicated that the mean contributions of agriculture,waste,vehicle,biomass burning,NH_(3)slip,and coal combustion were 9.9%±4.4%,8.3%±5.5%,29%±8.0%,16%±2.2%,25%±6.0%,and 12%±3.4%,respectively,at the ground site during the sampling campaign.By contrast,the contributions of sources at 488 m remained relatively stable due to the limited influence of local activities.Overall,our study highlights the dominant role of combustion sources in NH_(3)emissions in the PRD region,with their contribution being highly dependent on atmospheric height.
文摘Background：Autophagy has been found to be involved in animal and cell models ofatherosclerosis,but to date,it lacks general observation in human atherosclerotic plaques.Here,we investigated autophagy in smooth muscle cells （SMCs）,endothelial cells （ECs）,and macrophages in human atherosclerotic plaques via transmission electron microscopy （TEM）,western blotting,and immunohistochemistry analysis.Methods：The histopathologic morphology of these plaques was observed via hematoxylin and eosin staining.The ultrastructural morphology of the SMCs,ECs,and macrophages in these plaques was observed via TEM.The localization ofmicrotubule-associated protein 1 light chain 3 （MAP 1-LC3）,a relatively special maker ofautophagy,in plaques was observed by double fluorescent immunochemistty and western blotting.Results：All of these human atherosclerotic plaques were considered advanced and unstable in histologically observation.By double fluorescent immunochemistry,the expression of LC3-Ⅱ increased in the SMCs of the fibrous cap,the macrophages,and the microvascular ECs of the plaque shoulders.The protein level of LC3-Ⅱ by western blotting significantly increased in plaques compared with normal controls.In addition,TEM observation of plaques revealed certain features of autophagy in SMCs,ECs,and macrophages including the formation of myelin figures,vacuolization,and the accumulation of inclusions in the cytosol.These results indicate that autophagy is activated in SMCs,ECs,and macrophages in human advanced atherosclerotic plaques.Conclusions：Our study is to demonstrate the existence of autophagy in human atherosclerotic plaques by different methods,which may contribute to the development of pharmacological approaches to stabilize vulnerable and rupture-prone lesions.
基金supported by Key Projects of National Key Research and Development Program of the Ministry of Science and Technology of China(No.2017YFC0213005)National Natural Science Foundation of China(Grant No.21625701)+1 种基金Beijing Municipal Science and Technology Commission(No.Z191100009119001)the Samsung Advanced Institute of Technology.
文摘Agricultural sources and non-agricultural emissions contribute to gaseous ammonia(NH_(3))that plays a vital role in severe haze formation.Qualitative and quantitative contributions of these sources to ambient PM_(2.5)(particulate matter with an aerodynamic equivalent diameter below 2.5µm)concentrations remains uncertain.Stable nitrogen isotopic composition(δ^(15)N)of NH_(3)and NH_(4)+(δ^(15)N(NH_(3))andδ^(15)N(NH_(4)+),respectively)can yield valuable information about its sources and associated processes.This review provides an overview of the recent progress in analytical techniques forδ^(15)N(NH_(3))andδ^(15)N(NH_(4)+)measurement,sampling of atmospheric NH_(3)and NH_(4)+in the ambient air and their sources signature(e.g.,agricultural vs.fossil fuel),and isotope-based source apportionment of NH_(3)in urban atmosphere.This study highlights that collecting sample that are fully representative of emission sources remains a challenge in fingerprintingδ^(15)N(NH_(3))values of NH_(3)emission sources.Furthermore,isotopic fractionation during NH_(3)gas-to-particle conversion under varying ambient field conditions(e.g.,relative humidity,particle pH,temperature)remains unclear,which indicates more field and laboratory studies to validate theoretically predicted isotopic fractionation are required.Thus,this study concludes that lack of refinedδ^(15)N(NH_(3))fingerprints and full understanding of isotopic fractionation during aerosol formation in a laboratory and field conditions is a limitation for isotope-based source apportionment of NH_(3).More experimental work(in chamber studies)and theoretical estimations in combinations of field verification are necessary in characterizing isotopic fractionation under various environmental and atmospheric neutralization conditions,which would help to better interpret isotopic data and our understanding on NH_(x)(NH_(3)+NH_(4)+)dynamics in the atmosphere.
基金supported by the National Natural Science Foundation of China(42130513,41905110,and 41961130384)the Royal Society Newton Advanced Fellowship,United Kingdom(NAFR1191220)the Research Grants Council of the Hong Kong Special Administrative Region,China(T24/504/17 and A-Poly U502/16)。
文摘Aerosol ammonium(NH_(4)^(+)),mainly produced from the reactions of ammonia(NH_(3))with acids in the atmosphere,has significant impacts on air pollution,radiative forcing,and human health.Understanding the source and formation mechanism of NH_(4)^(+)can provide scientific insights into air quality improvements.However,the sources of NH_(3)in urban areas are not well understood,and few studies focus on NH_(3)/NH_(4)^(+)at different heights within the atmospheric boundary layer,which hinders a comprehensive understanding of aerosol NH_(4)^(+).In this study,we perform both field observation and modeling studies(the Community Multiscale Air Quality,CMAQ)to investigate regional NH_(3)emission sources and vertically resolved NH_(4)^(+)formation mechanisms during the winter in Beijing.Both stable nitrogen isotope analyses and CMAQ model suggest that combustion-related NH_(3)emissions,including fossil fuel sources,NH_(3)slip,and biomass burning,are important sources of aerosol NH_(4)^(+)with more than 60%contribution occurring on heavily polluted days.In contrast,volatilization-related NH_(3)sources(livestock breeding,N-fertilizer application,and human waste)are dominant on clean days.Combustion-related NH_(3)is mostly local from Beijing,and biomass burning is likely an important NH_(3)source(~15%–20%)that was previously overlooked.More effective control strategies such as the two-product(e.g.,reducing both SO_(2)and NH_(3))control policy should be considered to improve air quality.
基金supported by the Scientific Research project of Department of Natural Resources of Hubei Province(No.ZRZY2020KJ10)Hubei Geological Bureau(No.KJ2019-3)+2 种基金the Shale Gas Geological Survey Projects of Department of Natural Resources of Hubei Province(Nos.HBCZ-17060223-170397 and DTCG-190409)We also thank the funds provided by Youth Foundation of the Northeast Petroleum University(No.2019QNL-21)Opening Fund of the Coal Reservoir Laboratory of National Engineering Research Center of CBM Development&Utilization,China University of Geosciences(Beijing)(No.2019MCQ02001)。
文摘The lower Cambrian Niutitang Formation is of crucial importance for shale gas target reservoirs in western Hubei,China;however,little work has been done in this field,and its shale gas accumulation and enrichment mechanism are still unclear.Based on survey wells,outcrop data,and large numbers of tests,the geological conditions of shale gas accumulation were studied;moreover,the factors that influence the gas content were thoroughly discussed.The results show that the Niutitang Formation(Є1n)can be divided into three sections:the first section(Є_(1)n^(1)),the second section(Є_(1)n^(2)),and the third section(Є1n3).TheЄ_(1)n^(2) is the main shale gas reservoir.The deep shelf facies is the main sedimentary facies and can be divided into three main lithofacies:argillaceous siltstone,carbonaceous shale and carbonaceous siliceous rock.The total organic carbon(TOC)content shows gentle growth trends until bottom of theЄ_(1)n^(2) and then decreases rapidly within theЄ_(1)n^(1),and the TOC content mainly ranges from 2%to 4%horizontally.The calcite and dolomite dissolution pores,clay intergranular pores and organic pores are the main pore types and the micropore types are clearly related to the mineral compositions and the TOC content.Vertically,the gas content is mainly affected by the TOC content.Horizontally,wells with high gas contents are distributed only southeast of the Huangling anticline,and the combination of structural styles,fault and fracture development,and the distribution of the regional unconformity boundary between the upper Sinian Dengying Formation(Z2d)and theЄ_(1)n^(2) are the three most important factors affecting the gas content.The favorable areas must meet the following conditions:a deep shelf environment,the presence of theЄ_(1)n^(1),wide and gentle folds,far from large normal faults that are more than 5 km,moderate thermal evolution,and greater than 500 m burial depth;this includes the block with the YD2–ZD2 wells,and the block with the Y1 and YD4 wells,which are distributed in the southern portion of the Huangling anticline and northern portion of the Xiannvshan fault.
基金supported by the National Key R&D Program(Grant No.2020YFD1000101)Special Funds for the Construction of Industrial Technology System of Modern Agriculture(Citrus)(CARS-26)+2 种基金Construction Project of Citrus Whole Course Mechanized Scientific Research Base(Agricultural Development Facility[2017]19)Hubei Agricultural Science and Technology Innovation Action Project,2021 Young Innovative Talents Project of General Colleges and Universities in Guangdong Province(Grant No.2021KQNCX128)Science and Technology Program of Guangdong Polytechnic College(Grant No.GKJ2021004).
文摘In order to study the influence rule of various factors on the operating power consumption of the traction orchard transporter and realize the optimal design of the operation power consumption of the transporter,according to the traditional experience and the existing research foundation,the monorail transporter test bench was designed and built on the basis of the whole structure and operation characteristics of the transporter.Taking the motor frequency,track gradient and load as the investigation factors,and the driving shaft power,shaft power transmission and mechanical efficiency as the evaluation indices,the orthogonal test was conducted,and the range analysis of the influence effect was carried out according to the test results.The primary and secondary orders of the influence of various factors were obtained that motor frequency was greater than track gradient and track gradient was greater than load.According to the orthogonal test results,the second-order response surface method was used to establish the optimization model of the power consumption of the transporter,and the model was verified on the test bench.The results showed that the relative error between the model optimization value and the test value based on the response surface power optimization model was less than 10%,which indicated that the power optimization model had satisfactory performance.The research can provide a reference for the orchard conveyor to choose the parameter combination which can save power consumption and the motor that matches power consumption.
基金The authors acknowledge that this work was supported by the National Key R&D Program(Grant No.2020YFD1000101)Special Funds for the Construction of Industrial Technology System of Modern Agriculture(Citrus)(Grant No.CARS-26)+2 种基金Construction Project of Citrus Whole Course Mechanized Scientific Research Base(Agricultural Development Facility[2017]19)Hubei Agricultural Science and Technology Innovation Action Project,Young Innovative Talents Project of General Colleges and Universities in Guangdong Province(Grant No.2018KQNCX311)Science and Technology Program of Guangdong Polytechnic College(Grant No.JXGG202030).
文摘To solve the problems of the traditional orchard conveyor,such as inflexible steering,a complex structure,poor stability and no power grid coverage,a remote-controlled rail conveyor powered by hydraulic pressure for mountainous orchards was designed and manufactured.Climbing stress analysis was carried out on a full-load trailer to obtain the maximum traction force,which met the requirement of the climbing slope of the transport mechanism.The key components of the conveyor were developed,such as the hydraulic transmission,the control system,safety protection devices,limiting devices,the throttle and decompression actuator,the counterweight tension and the battery.Through the theoretical calculations of key components,an orchard conveyor powered by diesel and hydraulic pressure was designed.Finally,the working performance of the transporter was tested through functionality,driving speed,system pressure and remote-controlled tests.The test results showed that the climbing angle of the transporter can reach 50°,the uphill load can reach 840 kg,the downhill load can reach 1100 kg,and the average running speed is 0.77 m/s;the driving speed ranges from 0.29 m/s to 1.08 m/s,and the system pressure ranges from 3.2 MPa to 10 MPa.The driving speed and system pressure are significantly affected by the load,and the remote control distance can reach 455 m.The technical specifications of the transporter meet all the design requirements,and the problem of stable operation of the transporter without power grid coverage has been addressed.The research results can well meet the practical application requirements of mountain orchard transportation without power grid coverage and provide theoretical reference for the design of key components of mountain orchard transportation machinery.
基金funded by the National Natural Science Foundation of China(21878010)the National Plan for Science,Technology and Innovation(MAARIFAH)King Abdulaziz City for Science and Technology,Kingdom of Saudi Arabia(14-PET2359-02).
文摘Ionic liquids have been extensively studied as solvents or catalysts for oxidative desulfurization(ODS)of diesel fuel,but it is still a challenge to reduce the desulfurization time and steps.In this work,a new highly efficient desulfurization system composed of CoFe_(2)O_(4) magnetic nanoparticle,[HMIM]Br-FeCl_(3) and H_(2)O_(2) was developed for the ODS of FCC diesel fuel.The desulfurization performances were investigated including desulfurization time,temperature,volume ratio of IL/oil,O/S molar ratio,dosage of CoFe_(2)O_(4),FeCl_(3) content in ILs,regeneration,and reuse of catalyst and solvent.Owing to the coupled catalytic roles of CoFe_(2)O_(4) magnetic nanoparticle and[HMIM]Br-FeCl_(3),where Co2t and Fe3t interact with H_(2)O_(2) to produce ·OH radical that converts S-compounds into sulfone and sulfoxide compounds,such a desulfurization system is highly effective in removing S-compound in diesel fuel.The S-content in FCC diesel fuel was reduced from the original 272.8 ppm to 0.5 ppm with 99.82%S-removal efficiency after one step within 8 minunder the optimal conditions of 25℃,8 min,V(IL/oil)=1:10,O/S=20,5 wt%CoFe_(2)O_(4) dosage and n([HMIM]Br)/n(FeCl_(3))=1:1;the desulfurization performance is much better in desulfurization time and steps than other desulfurization systems reported previously.The desulfurization system can be regenerated and reused without remarkable loss of desulfurization activity.A desulfurization mechanism was proposed.
