Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration eff...Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration efficiency,complex denitration system,and high investment and operating cost.Here we put forward a novel polymer non-catalytic reduction(PNCR)technology that utilized a new type of polymer agent to remove NO_(x),and the proposed PNCR technology was applied to the existing waste-to-energy plant to test the denitration performance.The PNCR technology demonstrated excellent denitration performance with a NO_(x) emission concentration of<100 mg/Nm^(3) and high denitration efficiency of>75%at the temperature range of 800-900℃,which showed the application feasibility even on the complex and unstable industrial operating conditions.In addition,PNCR and hybrid polymer/selective non-catalytic reduction(PNCR/SNCR)technology possessed remarkable economic advantages including low investment fee and low operating cost of<10 CNY per ton of municipal solid waste(MSW)compared with selective catalytic reduction(SCR)technology.The excellent denitration performance of PNCR technology forebodes a broad industrial application prospect in the field of flue gas cleaning for waste-to-energy plants.展开更多
In this paper,a wideband true time delay line for X-band is designed to overcome the beam dispersion problem in a high-resolution spaceborne synthetic aperture radar phased array antenna system.The delay line loads th...In this paper,a wideband true time delay line for X-band is designed to overcome the beam dispersion problem in a high-resolution spaceborne synthetic aperture radar phased array antenna system.The delay line loads the electromagnetic bandgap structure on the upper surface of the substrate integrated waveguide.This is equivalent to including an additional inductance-capacitance for energy storage,which realizes the slow-wave effect.A microstrip line-SIW tapered transition structure is introduced to achieve a low loss and a large bandwidth.In the frequency band between 8-12 GHz,the measured results show that the delay multiplier of the delay line reaches 4 times,i.e.,delay line’s delay time is 4 times larger than 50Ωmicrostrip line with same length.Furthermore,the delay fluctuation,i.e.,the difference between the maximum and minimum delay as a percentage of the standard delay is only 2.5%,the insertion loss is less than-2.5 dB,and the return loss is less than-15 dB.Compared with the existing delay lines,the proposed delay line has the advantages of high delay efficiency,low delay error,wide bandwidth and low loss,which has good practical value and application prospects.展开更多
Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling.However,the conventional trochoidal tool path presents challenges such as lowe...Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling.However,the conventional trochoidal tool path presents challenges such as lower machining efficiency and longer machining time due to its time-varying cutter-workpiece engagement angle and a high percentage of non-cutting tool paths.To address these issues,this paper introduces a parameter-variant trochoidal-like(PVTR)tool path planning method for chatter-free and high-efficiency milling.This method ensures a constant engagement angle for each tool path period by adjusting the trochoidal radius and step.Initially,the nonlinear equation for the PVTR toolpath is established.Then,a segmented recurrence method is proposed to plan tool paths based on the desired engagement angle.The impact of trochoidal tool path parameters on the engagement angle is analyzed and coupled this information with the milling stability model based on spindle speed and engagement angle to determine the desired engagement angle throughout the machining process.Finally,several experimental tests are carried out using the bull-nose end mill to validate the feasibility and effectiveness of the proposed method.展开更多
The delayed nitrogen application technology is a crucial method for achieving high yield and efficiency in wheat cultivation.Specifically,more nitrogen is supplied to the middle and late growth stages of wheat by adju...The delayed nitrogen application technology is a crucial method for achieving high yield and efficiency in wheat cultivation.Specifically,more nitrogen is supplied to the middle and late growth stages of wheat by adjusting the application time and proportion of nitrogen fertilizer.This approach helps improve the tiller-bearing percentage and increase the number of grains per ear and the thousand-grain weight,while also reducing nitrogen loss and enhancing fertilizer use efficiency.This paper systematically elaborated on the high-yield and high-efficiency cultivation technology system with delayed nitrogen application for wheat,covering variety selection,soil management,sowing technology,the principle and implementation methods of delayed nitrogen application,integrated water and fertilizer management,field management,and comprehensive pest and disease control.Considering the ecological characteristics of major wheat-growing regions in China,tailored technical solutions were proposed,and operational key points of critical technological steps were introduced in detail.Through scientific variety distribution,precise nitrogen management,and integrated pest control,wheat yield and quality can be enhanced while achieving cost saving,improved efficiency,and ecological environmental protection.This paper provides systematic theoretical guidance and practical references for promoting thedelayed nitrogen application technology in wheat,thereby supporting the sustainable development of China s wheat industry.展开更多
The manufacturing industry is the core support for the development of the real economy.While promoting rapid economic growth,it also brings severe resource and environmental challenges.China's manufacturing indust...The manufacturing industry is the core support for the development of the real economy.While promoting rapid economic growth,it also brings severe resource and environmental challenges.China's manufacturing industry has ranked first in the world in terms of energy consumption,accounting for 56%of China's total energy consumption.Its electricity consumption exceeds 50%of the total social electricity consumption,and its carbon emissions reach 1.81 billion tons,accounting for 34% of the national total.Against this backdrop,enhancing the sustainability of high-end equipment manufacturing industries represented by aerospace has become a major strategic need for China's modernization,and it also provides strong support for solving global environmental problems.展开更多
The agricultural sector, encompassing agriculture, forestry, and land use, significantly contributes to global greenhouse gas(GHG) emissions, accounting for 23% of the total(IPCC 2019). It faces substantial challenges...The agricultural sector, encompassing agriculture, forestry, and land use, significantly contributes to global greenhouse gas(GHG) emissions, accounting for 23% of the total(IPCC 2019). It faces substantial challenges due to population growth and the urgent need to reduce its GHG emissions. Livestock husbandry, a crucial component of agriculture, accounts for a significant proportion of agricultural GHG emissions(Nugrahaeningtyas et al. 2024). Reducing emissions from livestock is essential not only for addressing climate change but also for protecting the ecological environment and achieving sustainable development. This is a critical task for the future of our planet and the well-being of future generations.展开更多
Superelastic martensitic transformation(MT)confers a considerable elastocaloric response to shape memory alloys,but the significant hysteretic loss cripples the energy conversion efficiency.In the present work,large e...Superelastic martensitic transformation(MT)confers a considerable elastocaloric response to shape memory alloys,but the significant hysteretic loss cripples the energy conversion efficiency.In the present work,large elastocaloric effect with high refrigeration efficiency is realized in a polycrystalline Co_(50)V_(35)Ga_(15)Heusler alloy.Experimental results show that the studied alloy undergoes a paramagnetic type MT from L2_(1)cubic austenite to D0_(22)tetragonal martensite with a small thermal hysteresis(ΔT_(hys))of~3 K.By carefully examining the strain rate dependence of superelastic response,it is also found that the stress hysteresis(Δσ_(hys))consists of two components including intrinsic stress hysteresis(Δσ_(hys)^(int.))caused by inherent attribute of MT and extrinsic stress hysteresis(Δσ_(hys)^(ext.))aroused by applied strain rate.Accordingly,we put forward a strain relaxation equation to separate the relative contributions betweenΔσ_(hys)^(int.)andΔσ_(hys)^(ext.)quantitatively,which demonstrates that a smallΔT_(hys)is conducive to substantial decrease inΔσ_(hys)^(int.).Moreover,associated with stress-induced superelastic MT,large reversible adiabatic temperature changes(ΔT_(ad))higher than 11 K are achieved under an applied strain of 6.5%over a temperature range of at least 60 K.With the combination of a large elastocaloric cooling capacity and a low energy dissipation,significant improvements in refrigeration efficiency can be obtained in a wide strain range,being superior to those reported in most of typical elastocaloric materials near room temperature.展开更多
Assessment of SDG11.3.1 indicator of the United Nations Sustainable Development Goals(SDGs)is a valuable tool for policymakers in urban planning.This study aims to enhance the accuracy of the SDG11.3.1 evaluation and ...Assessment of SDG11.3.1 indicator of the United Nations Sustainable Development Goals(SDGs)is a valuable tool for policymakers in urban planning.This study aims to enhance the accuracy of the SDG11.3.1 evaluation and explore the impact of varying precision levels in urban built-up area on the indicator’s assessment outcomes.We developed an algorithm to generate accurate urban built-up area data products based on China’s Geographical Condition Monitoring data with a 2 m resolution.The study evaluates urban land-use efficiency in China from 2015 to 2020 across different geographical units using both the research product and data derived from other studies utilizing medium and low-resolution imagery.The results indicate:(1)A significant improvement in the accuracy of our urban built-up area data,with the SDG11.3.1 evaluation results demonstrating a more precise reflection of spatiotemporal characteristics.The indicator shows a positive correlation with the accuracy level of the built-up area data;(2)From 2015 to 2020,Chinese prefecture-level cities have undergone faster urbanization in terms of land expansion relative to population growth,leading to less optimal land resource utilization.Only in extra-large cities does urban population growth show a relatively balanced pattern.However,urban popula tion growth in other regions and cities of various sizes lags behind land urbanization.Notably,Northeast China and small to medium cities encounter significant challenges in urban population growth.The comprehensive framework developed for evaluating SDG11.3.1 with high-precision urban built-up area data can be adapted to different national regions,yielding more accurate SDG11.3.1 outcomes.Our urban area and built-up area data products provide crucial inputs for calculating at least four indicators related to SDG11.展开更多
The distributions of light and nitrogen within a plant's canopy reflect the growth adaptation of crops to the environment and are conducive to improving the carbon assimilation ability.So can the yield in crop pro...The distributions of light and nitrogen within a plant's canopy reflect the growth adaptation of crops to the environment and are conducive to improving the carbon assimilation ability.So can the yield in crop production be maximized by improving the light and nitrogen distributions without adding any additional inputs?In this study,the effects of different nitrogen application rates and planting densities on the canopy light and nitrogen distributions of two highyielding maize cultivars(XY335 and DH618)and the regulatory effects of canopy physiological characteristics on radiation use efficiency(RUE)and yield were studied based on high-yield field experiments in Qitai,Xinjiang Uygur Autonomous Region,China,during 2019 and 2020.The results showed that the distribution of photosynthetically active photon flux density(PPFD)in the maize canopy decreased from top to bottom,while the vertical distribution of specific leaf nitrogen(SLN)initially increased and then decreased from top to bottom in the canopy.When SLN began to decrease,the PPDF values of XY335 and DH618 were 0.5 and 0.3,respectively,corresponding to 40.6 and49.3%of the total leaf area index(LAI).Nitrogen extinction coefficient(K_(N))/light extinction coefficient(K_(L))ratio in the middle and lower canopy of XY335(0.32)was 0.08 higher than that of DH618(0.24).The yield and RUE of XY335(17.2 t ha^(-1)and 1.8g MJ^(-1))were 7.0%(1.1 t ha^(-1))and 13.7%(0.2 g MJ^(-1))higher than those of DH618(16.1 t ha^(-1)and 1.6 g MJ^(-1)).Therefore,better light conditions(where the proportion of LAI in the upper and middle canopy was small)improved the light distribution when SLN started to decline,thus helping to mobilize the nitrogen distribution and maintain a high K_(N)and K_(N)/K_(L)ratio.In addition,K_(N)/K_(L)was a key parameter for yield improvement when the maize nutrient requirements were met at 360 kg N ha^(-1).At this level,an appropriately optimized high planting density could promote nitrogen utilization and produce higher yields and greater efficiency.The results of this study will be important for achieving high maize yields and the high efficiency cultivation and breeding of maize in the future.展开更多
A novel Eu^(3+)-doped fluorapatite red phosphor Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2)Eu^(3+)with pure phase was synthesized in this study.Density functional theory(DFT)calculation and diffuse reflection spectrum a...A novel Eu^(3+)-doped fluorapatite red phosphor Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2)Eu^(3+)with pure phase was synthesized in this study.Density functional theory(DFT)calculation and diffuse reflection spectrum analysis reveal its potential as a matrix for phosphors excited by ultraviolet light.Eu^(3+)has a^(7)F_(0)→^(5)L_(6)transition at 394 nm,and the prepared phosphor exhibits a high emission intensity at 614 nm,which may be attributed to the^(5)D_(0)-^(7)F_(2)energy transition at the lower symmetry site of Eu^(3+).The optimal doping concentration of the phosphor is determined to be 11 mol%,with concentration quenching attributed to the exchange interaction mechanism.The overall color purity of the phosphor is up to 99.88%,with an internal quantum efficiency as high as 91.15%.Notably,Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2):11 mol%Eu^(3+)(CYBSF:11 mol%Eu^(3+))phosphors exhibit good thermal stability,with a thermal quenching temperature(T1/2)of 552 K and the intensity of emission at 423 K still at 88.89%of that at 298 K.The activation energy of the phosphor is up to 0.30287 eV.Its comprehensive luminescence performance surpasses that of commercial red phosphor,making it suitable for near ultraviolet excited warm white light emitting diode(NUV-WLED)with a high color rendering index(Ra=82)and a correlated color temperature(CCT)of 4339 K.Moreover,the phosphor achieves latent fingerprint visualization and anti-counterfeiting ink on different material surfaces:glass,aluminum foil,plastic and paper.Overall,the fluorapatite CYBSF:11 mol%Eu^(3+)phosphor holds great potential for multimodal applications due to its high quantum efficiency and good thermal stability.展开更多
The adsorption of pollutants can not only promote the direct surface reaction,but also modify the catalyst itself to improve its photoelectric characteristics,which is rarely studied for water treatment with inorganic...The adsorption of pollutants can not only promote the direct surface reaction,but also modify the catalyst itself to improve its photoelectric characteristics,which is rarely studied for water treatment with inorganic photocatalyst.A highly crystalline BiOBr(c-BiOBr)was synthesized by a two-step preparation process.Owing to the calcination,the highly crystalline enhanced the interface interaction between pollutant and c-BiOBr.The complex of organic pollutant and[Bi_(2)O_(2)]^(2+)could promote the active electron transfer from the adsorbed pollutant to c-BiOBr for the direct pollutant degradation by holes(h^(+)).Moreover,the pollutant adsorption actually modified c-BiOBr and promoted more unpaired electrons,which would coupling with the photoexcitation to promote generate more O_(2)^(•-).The molecular modification effect derived from pollutant adsorption significantly improved the removal of pollutants.This work strongly deepens the understanding of the molecularmodification effect from the pollutant adsorption and develops a novel and efficient approach for water treatment.展开更多
Fischer-Tropsch synthesis offers a promising route to convert carbon-rich resources such as coal,natural gas,and biomass into clean fuels and high-value chemicals via syngas.Catalyst development is crucial for optimiz...Fischer-Tropsch synthesis offers a promising route to convert carbon-rich resources such as coal,natural gas,and biomass into clean fuels and high-value chemicals via syngas.Catalyst development is crucial for optimizing the process,with cobalt-and iron-based catalysts being widely used in industrial applications.Iron-based catalysts,in particular,are favored due to their low cost,broad temperature range,and high water-gas shift reaction activity,making them ideal for syngas derived from coal and biomass with a low H_(2)/CO ratio.However,despite their long history of industrial use,iron-based catalysts face two significant challenges.First,the presence of multiple iron phases-metallic iron,iron oxides,and iron carbides-complicates the understanding of the reaction mechanism due to dynamic phase transformations.Second,the high water-gas shift activity of these catalysts leads to increased CO_(2) selectivity,thereby reducing overall carbon efficiency.In Fischer-Tropsch synthesis,CO_(2) can arise as primary CO_(2) from CO disproportionation(the Boudouard reaction)and as secondary CO_(2) from the water-gas shift reaction.The accumulation of CO_(2) formation further compromises overall carbon efficiency,which is particularly undesirable given the current focus on minimizing carbon emissions and achieving carbon neutrality.This review focus on the ongoing advancements of iron-based catalysts for Fischer-Tropsch synthesis,with particular emphasis on overcoming these two critical challenges for iron-based catalysts:regulating the active phases and minimizing CO_(2) selectivity.Addressing these challenges is essential for enhancing the overall catalytic efficiency and selectivity of iron-based catalysts.In this review,recent efforts to suppress CO_(2) selectivity of iron-based catalysts,including catalyst hydrophobic modification and graphene confinement,are explored for their potential to stabilize active phases and prevent unwanted side reactions.This innovative approach offers new opportunities for developing catalysts with high activity,low CO_(2) selectivity,and enhanced stability,which are key factors for enhancing both the efficiency and sustainability for Fischer-Tropsch synthesis.Such advancements are crucial for advancing more efficient and sustainable Fischer-Tropsch synthesis technologies,supporting the global push for net-zero emissions goals,and contributing to carbon reduction efforts worldwide.展开更多
The utilization of ironsand for preparing oxidized pellets poses challenges,including slow oxidation and low consolidation strength.The effects and function mechanisms of high-pressure grinding roll(HPGR)pretreatment ...The utilization of ironsand for preparing oxidized pellets poses challenges,including slow oxidation and low consolidation strength.The effects and function mechanisms of high-pressure grinding roll(HPGR)pretreatment on the oxidation and consolidation of ironsand pellets were investigated,and the energy utilization efficiency of HPGR with different roller pressure intensities was evaluated.The results indicate that HPGR pretreatment at 8 MPa improves the ironsand properties,with the specific surface area increasing by 740 cm^(2) g^(-1) and mechanical energy storage increasing by 2.5 kJ mol^(-1),which is conducive to oxidation and crystalline connection of particles.As roller pressure intensity increases to 16 MPa,more mechanical energy of HPGR is applied for crystal activation,with mechanical energy storage further rising by 18.1 kJ mol^(-1).The apparent activation energy for pellet oxidation initially decreases and then increases,reaching a minimum at 12 MPa.Simultaneously,the roasted pellets porosity decreases by 2.8%,while the compressive strength increases by 789 N.At higher roller pressure intensity,the densely connected structure between particles impedes gas diffusion within the pellets,diminishing the beneficial effects of HPGR on pellet oxidation.Moreover,excessive roller pressure intensity decreases the HPGR energy utilization efficiency.The optimal HPGR roller pressure intensity for ironsand is 12 MPa,at which the specific surface area increases by 790 cm^(2) g^(-1),mechanical energy storage increases by 10.6 kJ mol^(-1),the compressive strength of roasted pellets rises to 2816 N,and the appropriate preheating and roasting temperatures decrease by 250 and 125°C,respectively.展开更多
Abundant efforts have been devoted to improving the efficiency of organic light-emitting diodes(OLEDs),however,approaches to control the device efficiency roll-off are still extremely limited,especially in nondoped bl...Abundant efforts have been devoted to improving the efficiency of organic light-emitting diodes(OLEDs),however,approaches to control the device efficiency roll-off are still extremely limited,especially in nondoped blue OLEDs.In this work,three blue emitters(TAT,TAMT and TAMT-CN)with"hot exciton"properties are designed and synthesized based on[1,2,4]triazolo[1,5-a]pyridine(TP)as a regulating unit as well as anthracene-triphenylamine(An-TPA)as the chromophore.By adjusting the linkage mode and modifying the TP unit,the excited state properties,carrier transfer abilities,horizontal orientation,and device efficiency roll-off were precisely controlled.Among these materials,emitters that directly connect the fused TP unit exhibit balanced charge-transporting ability,higher photoluminescent quantum yield and improved horizontal orientation,resulting in better electroluminescence(EL)performance in non-doped blue OLEDs.As a result,non-doped blue OLEDs exhibit excellent performance with external quantum efficiencies of over 6%,brightness of over 30,000 cd/m2and EL peaks of around 476 nm.More importantly,the device based on TAMT-CN exhibits an ultra-low efficiency roll-off of 2.97%at a high brightness of10,000 cd/m2.The accessible molecular unit and feasible design strategy in this work are of great significance for designing highly efficient and ultra-low efficiency roll-off non-doped blue OLEDs.展开更多
Advanced oxidation processes are promising for degradation of the highly chemical stability and refractory methylisothiazolinone(MIT) bactericides in relevant industrial wastewater.In order to assemble a low cost and ...Advanced oxidation processes are promising for degradation of the highly chemical stability and refractory methylisothiazolinone(MIT) bactericides in relevant industrial wastewater.In order to assemble a low cost and high performance electrochemical oxidation system for wastewater treatment,granular active carbon(GAC) was decorated by doping Ce,Sn,Sb to synthesize Sn-Sb-Ce/GAC using sol-gel method as particle electrode filled into a three-dimensional(3D) electrochemical reactor.Scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS) and X-ray diffraction(XRD) experiments revealed that the Sn-Sb-Ce/GAC particle electrode crystal particles were compact and uniform,and the surface structure was improved.The ten cyclic experiments indicated that the Sn-Sb-Ce/GAC particle electrode had high stability and low dissolution of the loaded active substance.The degradation mechanism of MIT was studied under the optimal working conditions of 3D electrode system with GAC of 5 g/L,current density of 20 mA/cm^(2),initial pH 5,electrolyte concentration of Na_(2)SO_(4)0.02 mol/L and reaction time of 120 min.The indirect electrochemical degradation of MIT was dominated by active substance pathway that active chlorine rather than free radicals(·OH) played the main role.Comparing with conventional two-dimensional(2D) electrode system,the 3D electrochemical system has larger active electrode area,higher treatment efficiency and lower energy consumption than the former.The 3D electrochemical system could remove 96.5% of MIT from the actual high-salt reverse osmosis concentrate wastewater in 30 min.It has a certain removal effect on UV_(254)in wastewater,but has a better removal effect on fluorescent substances.This study proposed a new strategy to develop transition metal and rare earth metal particle electrodes using carbon-based materials for high efficient electrocatalytic oxidation in the electrochemical treatment system.展开更多
An easily stackable multi-layer quasi-zero-stiffness(ML-QZS)meta-structure is proposed to achieve highly efficient vibration isolation performance at low frequency.First,the distributed shape optimization method is us...An easily stackable multi-layer quasi-zero-stiffness(ML-QZS)meta-structure is proposed to achieve highly efficient vibration isolation performance at low frequency.First,the distributed shape optimization method is used to design the unit cel,i.e.,the single-layer QZS(SL-QZS)meta-structure.Second,the stiffness feature of the unit cell is investigated and verified through static experiments.Third,the unit cells are stacked one by one along the direction of vibration isolation,and thus the ML-QZS meta-structure is constructed.Fourth,the dynamic modeling of the ML-QZS vibration isolation metastructure is conducted,and the dynamic responses are obtained from the equations of motion,and verified by finite element(FE)simulations.Finally,a prototype of the ML-QZS vibration isolation meta-structure is fabricated by additive manufacturing,and the vibration isolation performance is evaluated experimentally.The results show that the vibration isolation performance substantially enhances when the number of unit cells increases.More importantly,the ML-QZS meta-structure can be easily extended in the direction of vibration isolation when the unit cells are properly stacked.Hence,the ML-FQZS vibration isolation meta-structure should be a fascinating solution for highly efficient vibration isolation performance at low frequency.展开更多
Solar steam generation(SSG)is widely regarded as one of the most sustainable technologies for seawater desalination.However,salt fouling severely compromises the evaporation performance and lifetime of evaporators,lim...Solar steam generation(SSG)is widely regarded as one of the most sustainable technologies for seawater desalination.However,salt fouling severely compromises the evaporation performance and lifetime of evaporators,limiting their practical applications.Herein,we propose a hierarchical salt-rejection(HSR)strategy to prevent salt precipitation during long-term evaporation while maintaining a rapid evaporation rate,even in high-salinity brine.The salt diffusion process is segmented into three steps—insulation,branching diffusion,and arterial transport—that significantly enhance the salt-resistance properties of the evaporator.Moreover,the HSR strategy overcomes the tradeoff between salt resistance and evaporation rate.Consequently,a high evaporation rate of 2.84 kg m^(-2) h^(-1),stable evaporation for 7 days cyclic tests in 20 wt%NaCl solution,and continuous operation for 170 h in natural seawater under 1 sun illumination were achieved.Compared with control evaporators,the HSR evaporator exhibited a>54%enhancement in total water evaporation mass during 24 h continuous evaporation in 20 wt%salt water.Furthermore,a water collection device equipped with the HSR evaporator realized a high water purification rate(1.1 kg m^(-2) h^(-1)),highlighting its potential for agricultural applications.展开更多
Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosyste...Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosystems.However,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain unclear.This study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–2020.Results indicated an annual mean WUE of 0.8088 gC/mm·m^(2)across the plateau,with a spatial gradient reflecting decrease from the southeast toward the northwest.Areas manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,respectively.Remarkably,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of increase.Environmental factors accounted for 70.79%of the variability in WUE.The leaf area index and temperature served as the major driving forces of WUE variation.展开更多
Experimental methods,including mercury pressure,nuclear magnetic resonance(NMR)and core(wateroil)displacement,are used to examine the effects of high-multiple water injection(i.e.water injection with high injected por...Experimental methods,including mercury pressure,nuclear magnetic resonance(NMR)and core(wateroil)displacement,are used to examine the effects of high-multiple water injection(i.e.water injection with high injected pore volume)on rock properties,pore structure and oil displacement efficiency of an oilfield in the western South China Sea.The results show an increase in the permeability of rocks along with particle migration,an increase in the pore volume and the average pore throat radius,and enhanced heterogeneity after high-multiple water injection.Compared with normal water injection methods,a high-multiple water injection is more effective in improving the oil displacement efficiency.The degree of recovery increases faster in the early stage due to the expansion of the swept area,and the transition from oil-wet to water-wet.The degree of recovery increases less in the late stage due to various factors,including the enhancement of heterogeneity in the rocks.Considering both the economic aspect and the production limit of water flooding,it is recommended to adopt other technologies to further enhance oil recovery after 300 PV water injection.展开更多
Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal condu...Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal conductivities of phase-change materials(PCMs)promote Joule heating dissi-pation.Repeated phase transitions also induce long-range atomic diffusion,limiting the durability.To address these challenges,phase-change heterostructure(PCH)devices that incorporate confinement sub-layers based on transition-metal dichalcogenide materials have been developed.In this study,we engi-neered a PCH device by integrating HfTe_(2),which has low thermal conductivity and excellent stability,into the PCM to realize PCRAM with enhanced thermal efficiency and structural stability.HEAT sim-ulations were conducted to validate the superior heat confinement in the programming region of the HfTe_(2)-based PCH device.Moreover,electrical measurements of the device demonstrated its outstanding performance,which was characterized by a low RESET current(∼1.6 mA),stable two-order ON/OFF ratio,and exceptional cycling endurance(∼2×10^(7)).The structural integrity of the HfTe_(2)confinement sub-layer was confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy.The material properties,including electrical conductivity,cohesive energy,and electronegativity,substantiated these findings.Collectively,these results revealed that the HfTe_(2)-based PCH device can achieve significant improvements in performance and reliability compared with conventional PCRAM devices.展开更多
基金supported by the National Natural Science Foundation of China(No.92367107)。
文摘Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration efficiency,complex denitration system,and high investment and operating cost.Here we put forward a novel polymer non-catalytic reduction(PNCR)technology that utilized a new type of polymer agent to remove NO_(x),and the proposed PNCR technology was applied to the existing waste-to-energy plant to test the denitration performance.The PNCR technology demonstrated excellent denitration performance with a NO_(x) emission concentration of<100 mg/Nm^(3) and high denitration efficiency of>75%at the temperature range of 800-900℃,which showed the application feasibility even on the complex and unstable industrial operating conditions.In addition,PNCR and hybrid polymer/selective non-catalytic reduction(PNCR/SNCR)technology possessed remarkable economic advantages including low investment fee and low operating cost of<10 CNY per ton of municipal solid waste(MSW)compared with selective catalytic reduction(SCR)technology.The excellent denitration performance of PNCR technology forebodes a broad industrial application prospect in the field of flue gas cleaning for waste-to-energy plants.
基金Supported by the National Natural Science Foundation of China(61971401)。
文摘In this paper,a wideband true time delay line for X-band is designed to overcome the beam dispersion problem in a high-resolution spaceborne synthetic aperture radar phased array antenna system.The delay line loads the electromagnetic bandgap structure on the upper surface of the substrate integrated waveguide.This is equivalent to including an additional inductance-capacitance for energy storage,which realizes the slow-wave effect.A microstrip line-SIW tapered transition structure is introduced to achieve a low loss and a large bandwidth.In the frequency band between 8-12 GHz,the measured results show that the delay multiplier of the delay line reaches 4 times,i.e.,delay line’s delay time is 4 times larger than 50Ωmicrostrip line with same length.Furthermore,the delay fluctuation,i.e.,the difference between the maximum and minimum delay as a percentage of the standard delay is only 2.5%,the insertion loss is less than-2.5 dB,and the return loss is less than-15 dB.Compared with the existing delay lines,the proposed delay line has the advantages of high delay efficiency,low delay error,wide bandwidth and low loss,which has good practical value and application prospects.
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A20202 and 52275477).
文摘Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling.However,the conventional trochoidal tool path presents challenges such as lower machining efficiency and longer machining time due to its time-varying cutter-workpiece engagement angle and a high percentage of non-cutting tool paths.To address these issues,this paper introduces a parameter-variant trochoidal-like(PVTR)tool path planning method for chatter-free and high-efficiency milling.This method ensures a constant engagement angle for each tool path period by adjusting the trochoidal radius and step.Initially,the nonlinear equation for the PVTR toolpath is established.Then,a segmented recurrence method is proposed to plan tool paths based on the desired engagement angle.The impact of trochoidal tool path parameters on the engagement angle is analyzed and coupled this information with the milling stability model based on spindle speed and engagement angle to determine the desired engagement angle throughout the machining process.Finally,several experimental tests are carried out using the bull-nose end mill to validate the feasibility and effectiveness of the proposed method.
基金Supported by The Key Science and Technology Project of Shangqiu City(2024056).
文摘The delayed nitrogen application technology is a crucial method for achieving high yield and efficiency in wheat cultivation.Specifically,more nitrogen is supplied to the middle and late growth stages of wheat by adjusting the application time and proportion of nitrogen fertilizer.This approach helps improve the tiller-bearing percentage and increase the number of grains per ear and the thousand-grain weight,while also reducing nitrogen loss and enhancing fertilizer use efficiency.This paper systematically elaborated on the high-yield and high-efficiency cultivation technology system with delayed nitrogen application for wheat,covering variety selection,soil management,sowing technology,the principle and implementation methods of delayed nitrogen application,integrated water and fertilizer management,field management,and comprehensive pest and disease control.Considering the ecological characteristics of major wheat-growing regions in China,tailored technical solutions were proposed,and operational key points of critical technological steps were introduced in detail.Through scientific variety distribution,precise nitrogen management,and integrated pest control,wheat yield and quality can be enhanced while achieving cost saving,improved efficiency,and ecological environmental protection.This paper provides systematic theoretical guidance and practical references for promoting thedelayed nitrogen application technology in wheat,thereby supporting the sustainable development of China s wheat industry.
基金the support of the National Natural Science Foundation of China(Nos.52205476 and 52175415)the Natural Science Foundation of Jiangsu Province(No.BK20242040)+1 种基金the Fundamental Research Funds for the Central Universities(No.NG2024008)the Fund of Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology(No.1005ZAA20003-14)。
文摘The manufacturing industry is the core support for the development of the real economy.While promoting rapid economic growth,it also brings severe resource and environmental challenges.China's manufacturing industry has ranked first in the world in terms of energy consumption,accounting for 56%of China's total energy consumption.Its electricity consumption exceeds 50%of the total social electricity consumption,and its carbon emissions reach 1.81 billion tons,accounting for 34% of the national total.Against this backdrop,enhancing the sustainability of high-end equipment manufacturing industries represented by aerospace has become a major strategic need for China's modernization,and it also provides strong support for solving global environmental problems.
文摘The agricultural sector, encompassing agriculture, forestry, and land use, significantly contributes to global greenhouse gas(GHG) emissions, accounting for 23% of the total(IPCC 2019). It faces substantial challenges due to population growth and the urgent need to reduce its GHG emissions. Livestock husbandry, a crucial component of agriculture, accounts for a significant proportion of agricultural GHG emissions(Nugrahaeningtyas et al. 2024). Reducing emissions from livestock is essential not only for addressing climate change but also for protecting the ecological environment and achieving sustainable development. This is a critical task for the future of our planet and the well-being of future generations.
基金supported by the National Natural Science Foundation of China(Nos.52261035,52201223,52371006,52371194)Applied Basic Projects of Yunnan province(No.202101BA070001-233).
文摘Superelastic martensitic transformation(MT)confers a considerable elastocaloric response to shape memory alloys,but the significant hysteretic loss cripples the energy conversion efficiency.In the present work,large elastocaloric effect with high refrigeration efficiency is realized in a polycrystalline Co_(50)V_(35)Ga_(15)Heusler alloy.Experimental results show that the studied alloy undergoes a paramagnetic type MT from L2_(1)cubic austenite to D0_(22)tetragonal martensite with a small thermal hysteresis(ΔT_(hys))of~3 K.By carefully examining the strain rate dependence of superelastic response,it is also found that the stress hysteresis(Δσ_(hys))consists of two components including intrinsic stress hysteresis(Δσ_(hys)^(int.))caused by inherent attribute of MT and extrinsic stress hysteresis(Δσ_(hys)^(ext.))aroused by applied strain rate.Accordingly,we put forward a strain relaxation equation to separate the relative contributions betweenΔσ_(hys)^(int.)andΔσ_(hys)^(ext.)quantitatively,which demonstrates that a smallΔT_(hys)is conducive to substantial decrease inΔσ_(hys)^(int.).Moreover,associated with stress-induced superelastic MT,large reversible adiabatic temperature changes(ΔT_(ad))higher than 11 K are achieved under an applied strain of 6.5%over a temperature range of at least 60 K.With the combination of a large elastocaloric cooling capacity and a low energy dissipation,significant improvements in refrigeration efficiency can be obtained in a wide strain range,being superior to those reported in most of typical elastocaloric materials near room temperature.
基金funded by the National Key Research and De-velopment Program of China(Grant No.2023YFC3804001)the Natural Resources Planning and Management Project(Grant No.A2417,A2418)the Fundamental Scientific Research Funds for Central Public Wel-fare Research Institutes(Grant No.AR2409).
文摘Assessment of SDG11.3.1 indicator of the United Nations Sustainable Development Goals(SDGs)is a valuable tool for policymakers in urban planning.This study aims to enhance the accuracy of the SDG11.3.1 evaluation and explore the impact of varying precision levels in urban built-up area on the indicator’s assessment outcomes.We developed an algorithm to generate accurate urban built-up area data products based on China’s Geographical Condition Monitoring data with a 2 m resolution.The study evaluates urban land-use efficiency in China from 2015 to 2020 across different geographical units using both the research product and data derived from other studies utilizing medium and low-resolution imagery.The results indicate:(1)A significant improvement in the accuracy of our urban built-up area data,with the SDG11.3.1 evaluation results demonstrating a more precise reflection of spatiotemporal characteristics.The indicator shows a positive correlation with the accuracy level of the built-up area data;(2)From 2015 to 2020,Chinese prefecture-level cities have undergone faster urbanization in terms of land expansion relative to population growth,leading to less optimal land resource utilization.Only in extra-large cities does urban population growth show a relatively balanced pattern.However,urban popula tion growth in other regions and cities of various sizes lags behind land urbanization.Notably,Northeast China and small to medium cities encounter significant challenges in urban population growth.The comprehensive framework developed for evaluating SDG11.3.1 with high-precision urban built-up area data can be adapted to different national regions,yielding more accurate SDG11.3.1 outcomes.Our urban area and built-up area data products provide crucial inputs for calculating at least four indicators related to SDG11.
基金supported by the National Natural Science Foundation of China(32172118)the National Key Research and Development Program of China(2016YFD0300110 and 2016YFD0300101)+1 种基金the Basic Scientific Research Fund of Chinese Academy of Agricultural Sciences,China(S2022ZD05)the Agricultural Science and Technology Innovation Program,China(CAAS-ZDRW202004)。
文摘The distributions of light and nitrogen within a plant's canopy reflect the growth adaptation of crops to the environment and are conducive to improving the carbon assimilation ability.So can the yield in crop production be maximized by improving the light and nitrogen distributions without adding any additional inputs?In this study,the effects of different nitrogen application rates and planting densities on the canopy light and nitrogen distributions of two highyielding maize cultivars(XY335 and DH618)and the regulatory effects of canopy physiological characteristics on radiation use efficiency(RUE)and yield were studied based on high-yield field experiments in Qitai,Xinjiang Uygur Autonomous Region,China,during 2019 and 2020.The results showed that the distribution of photosynthetically active photon flux density(PPFD)in the maize canopy decreased from top to bottom,while the vertical distribution of specific leaf nitrogen(SLN)initially increased and then decreased from top to bottom in the canopy.When SLN began to decrease,the PPDF values of XY335 and DH618 were 0.5 and 0.3,respectively,corresponding to 40.6 and49.3%of the total leaf area index(LAI).Nitrogen extinction coefficient(K_(N))/light extinction coefficient(K_(L))ratio in the middle and lower canopy of XY335(0.32)was 0.08 higher than that of DH618(0.24).The yield and RUE of XY335(17.2 t ha^(-1)and 1.8g MJ^(-1))were 7.0%(1.1 t ha^(-1))and 13.7%(0.2 g MJ^(-1))higher than those of DH618(16.1 t ha^(-1)and 1.6 g MJ^(-1)).Therefore,better light conditions(where the proportion of LAI in the upper and middle canopy was small)improved the light distribution when SLN started to decline,thus helping to mobilize the nitrogen distribution and maintain a high K_(N)and K_(N)/K_(L)ratio.In addition,K_(N)/K_(L)was a key parameter for yield improvement when the maize nutrient requirements were met at 360 kg N ha^(-1).At this level,an appropriately optimized high planting density could promote nitrogen utilization and produce higher yields and greater efficiency.The results of this study will be important for achieving high maize yields and the high efficiency cultivation and breeding of maize in the future.
基金supported by the National Natural Science Foundation of China(52372013)Natural Science Foundation of Shanghai(22ZR1460600)。
文摘A novel Eu^(3+)-doped fluorapatite red phosphor Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2)Eu^(3+)with pure phase was synthesized in this study.Density functional theory(DFT)calculation and diffuse reflection spectrum analysis reveal its potential as a matrix for phosphors excited by ultraviolet light.Eu^(3+)has a^(7)F_(0)→^(5)L_(6)transition at 394 nm,and the prepared phosphor exhibits a high emission intensity at 614 nm,which may be attributed to the^(5)D_(0)-^(7)F_(2)energy transition at the lower symmetry site of Eu^(3+).The optimal doping concentration of the phosphor is determined to be 11 mol%,with concentration quenching attributed to the exchange interaction mechanism.The overall color purity of the phosphor is up to 99.88%,with an internal quantum efficiency as high as 91.15%.Notably,Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2):11 mol%Eu^(3+)(CYBSF:11 mol%Eu^(3+))phosphors exhibit good thermal stability,with a thermal quenching temperature(T1/2)of 552 K and the intensity of emission at 423 K still at 88.89%of that at 298 K.The activation energy of the phosphor is up to 0.30287 eV.Its comprehensive luminescence performance surpasses that of commercial red phosphor,making it suitable for near ultraviolet excited warm white light emitting diode(NUV-WLED)with a high color rendering index(Ra=82)and a correlated color temperature(CCT)of 4339 K.Moreover,the phosphor achieves latent fingerprint visualization and anti-counterfeiting ink on different material surfaces:glass,aluminum foil,plastic and paper.Overall,the fluorapatite CYBSF:11 mol%Eu^(3+)phosphor holds great potential for multimodal applications due to its high quantum efficiency and good thermal stability.
基金supported by National Natural Science Foundation of China (Nos.52100032,51838005)Shandong Province Postdoctoral Program for Innovative Talent Support Plan (No.SDBX2022003)the Introduced Innovative R&D Team Project under the“The Pearl River Talent Recruitment Program”of Guangdong Province (2019ZT08L387).
文摘The adsorption of pollutants can not only promote the direct surface reaction,but also modify the catalyst itself to improve its photoelectric characteristics,which is rarely studied for water treatment with inorganic photocatalyst.A highly crystalline BiOBr(c-BiOBr)was synthesized by a two-step preparation process.Owing to the calcination,the highly crystalline enhanced the interface interaction between pollutant and c-BiOBr.The complex of organic pollutant and[Bi_(2)O_(2)]^(2+)could promote the active electron transfer from the adsorbed pollutant to c-BiOBr for the direct pollutant degradation by holes(h^(+)).Moreover,the pollutant adsorption actually modified c-BiOBr and promoted more unpaired electrons,which would coupling with the photoexcitation to promote generate more O_(2)^(•-).The molecular modification effect derived from pollutant adsorption significantly improved the removal of pollutants.This work strongly deepens the understanding of the molecularmodification effect from the pollutant adsorption and develops a novel and efficient approach for water treatment.
文摘Fischer-Tropsch synthesis offers a promising route to convert carbon-rich resources such as coal,natural gas,and biomass into clean fuels and high-value chemicals via syngas.Catalyst development is crucial for optimizing the process,with cobalt-and iron-based catalysts being widely used in industrial applications.Iron-based catalysts,in particular,are favored due to their low cost,broad temperature range,and high water-gas shift reaction activity,making them ideal for syngas derived from coal and biomass with a low H_(2)/CO ratio.However,despite their long history of industrial use,iron-based catalysts face two significant challenges.First,the presence of multiple iron phases-metallic iron,iron oxides,and iron carbides-complicates the understanding of the reaction mechanism due to dynamic phase transformations.Second,the high water-gas shift activity of these catalysts leads to increased CO_(2) selectivity,thereby reducing overall carbon efficiency.In Fischer-Tropsch synthesis,CO_(2) can arise as primary CO_(2) from CO disproportionation(the Boudouard reaction)and as secondary CO_(2) from the water-gas shift reaction.The accumulation of CO_(2) formation further compromises overall carbon efficiency,which is particularly undesirable given the current focus on minimizing carbon emissions and achieving carbon neutrality.This review focus on the ongoing advancements of iron-based catalysts for Fischer-Tropsch synthesis,with particular emphasis on overcoming these two critical challenges for iron-based catalysts:regulating the active phases and minimizing CO_(2) selectivity.Addressing these challenges is essential for enhancing the overall catalytic efficiency and selectivity of iron-based catalysts.In this review,recent efforts to suppress CO_(2) selectivity of iron-based catalysts,including catalyst hydrophobic modification and graphene confinement,are explored for their potential to stabilize active phases and prevent unwanted side reactions.This innovative approach offers new opportunities for developing catalysts with high activity,low CO_(2) selectivity,and enhanced stability,which are key factors for enhancing both the efficiency and sustainability for Fischer-Tropsch synthesis.Such advancements are crucial for advancing more efficient and sustainable Fischer-Tropsch synthesis technologies,supporting the global push for net-zero emissions goals,and contributing to carbon reduction efforts worldwide.
基金financially supported by the General Program of National Natural Science Foundation of China(No.52174330)Hunan Provincial Innovation Foundation for Postgraduate(No.QL20220069)Postgraduate Innovative Project of Central South University(No.1053320214756).
文摘The utilization of ironsand for preparing oxidized pellets poses challenges,including slow oxidation and low consolidation strength.The effects and function mechanisms of high-pressure grinding roll(HPGR)pretreatment on the oxidation and consolidation of ironsand pellets were investigated,and the energy utilization efficiency of HPGR with different roller pressure intensities was evaluated.The results indicate that HPGR pretreatment at 8 MPa improves the ironsand properties,with the specific surface area increasing by 740 cm^(2) g^(-1) and mechanical energy storage increasing by 2.5 kJ mol^(-1),which is conducive to oxidation and crystalline connection of particles.As roller pressure intensity increases to 16 MPa,more mechanical energy of HPGR is applied for crystal activation,with mechanical energy storage further rising by 18.1 kJ mol^(-1).The apparent activation energy for pellet oxidation initially decreases and then increases,reaching a minimum at 12 MPa.Simultaneously,the roasted pellets porosity decreases by 2.8%,while the compressive strength increases by 789 N.At higher roller pressure intensity,the densely connected structure between particles impedes gas diffusion within the pellets,diminishing the beneficial effects of HPGR on pellet oxidation.Moreover,excessive roller pressure intensity decreases the HPGR energy utilization efficiency.The optimal HPGR roller pressure intensity for ironsand is 12 MPa,at which the specific surface area increases by 790 cm^(2) g^(-1),mechanical energy storage increases by 10.6 kJ mol^(-1),the compressive strength of roasted pellets rises to 2816 N,and the appropriate preheating and roasting temperatures decrease by 250 and 125°C,respectively.
基金the financial support from the National Natural Science Foundation of China(Nos.52273187 and 51973107)the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme 2019(No.GDUPS2019)。
文摘Abundant efforts have been devoted to improving the efficiency of organic light-emitting diodes(OLEDs),however,approaches to control the device efficiency roll-off are still extremely limited,especially in nondoped blue OLEDs.In this work,three blue emitters(TAT,TAMT and TAMT-CN)with"hot exciton"properties are designed and synthesized based on[1,2,4]triazolo[1,5-a]pyridine(TP)as a regulating unit as well as anthracene-triphenylamine(An-TPA)as the chromophore.By adjusting the linkage mode and modifying the TP unit,the excited state properties,carrier transfer abilities,horizontal orientation,and device efficiency roll-off were precisely controlled.Among these materials,emitters that directly connect the fused TP unit exhibit balanced charge-transporting ability,higher photoluminescent quantum yield and improved horizontal orientation,resulting in better electroluminescence(EL)performance in non-doped blue OLEDs.As a result,non-doped blue OLEDs exhibit excellent performance with external quantum efficiencies of over 6%,brightness of over 30,000 cd/m2and EL peaks of around 476 nm.More importantly,the device based on TAMT-CN exhibits an ultra-low efficiency roll-off of 2.97%at a high brightness of10,000 cd/m2.The accessible molecular unit and feasible design strategy in this work are of great significance for designing highly efficient and ultra-low efficiency roll-off non-doped blue OLEDs.
基金the financial supports from Major Science and Technology project of China Power Engineering Consulting Group Co., Ltd. "Research on Green and digital Intelligent Technology of Sewage Treatment Plant" (No. CEEC2023-ZDYF-09)Technology Innovation Ability Improvement Project of Shandong Province, China (No. 2022TSGC1247)。
文摘Advanced oxidation processes are promising for degradation of the highly chemical stability and refractory methylisothiazolinone(MIT) bactericides in relevant industrial wastewater.In order to assemble a low cost and high performance electrochemical oxidation system for wastewater treatment,granular active carbon(GAC) was decorated by doping Ce,Sn,Sb to synthesize Sn-Sb-Ce/GAC using sol-gel method as particle electrode filled into a three-dimensional(3D) electrochemical reactor.Scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS) and X-ray diffraction(XRD) experiments revealed that the Sn-Sb-Ce/GAC particle electrode crystal particles were compact and uniform,and the surface structure was improved.The ten cyclic experiments indicated that the Sn-Sb-Ce/GAC particle electrode had high stability and low dissolution of the loaded active substance.The degradation mechanism of MIT was studied under the optimal working conditions of 3D electrode system with GAC of 5 g/L,current density of 20 mA/cm^(2),initial pH 5,electrolyte concentration of Na_(2)SO_(4)0.02 mol/L and reaction time of 120 min.The indirect electrochemical degradation of MIT was dominated by active substance pathway that active chlorine rather than free radicals(·OH) played the main role.Comparing with conventional two-dimensional(2D) electrode system,the 3D electrochemical system has larger active electrode area,higher treatment efficiency and lower energy consumption than the former.The 3D electrochemical system could remove 96.5% of MIT from the actual high-salt reverse osmosis concentrate wastewater in 30 min.It has a certain removal effect on UV_(254)in wastewater,but has a better removal effect on fluorescent substances.This study proposed a new strategy to develop transition metal and rare earth metal particle electrodes using carbon-based materials for high efficient electrocatalytic oxidation in the electrochemical treatment system.
基金supported by the National Natural Science Foundation of China(Nos.12122206 and 12272129)the Natural Science Foundation of Hunan Province of China(No.2024JJ4004)the Zhejiang Provincial Natural Science Foundation of China(No.LQ24A020006)。
文摘An easily stackable multi-layer quasi-zero-stiffness(ML-QZS)meta-structure is proposed to achieve highly efficient vibration isolation performance at low frequency.First,the distributed shape optimization method is used to design the unit cel,i.e.,the single-layer QZS(SL-QZS)meta-structure.Second,the stiffness feature of the unit cell is investigated and verified through static experiments.Third,the unit cells are stacked one by one along the direction of vibration isolation,and thus the ML-QZS meta-structure is constructed.Fourth,the dynamic modeling of the ML-QZS vibration isolation metastructure is conducted,and the dynamic responses are obtained from the equations of motion,and verified by finite element(FE)simulations.Finally,a prototype of the ML-QZS vibration isolation meta-structure is fabricated by additive manufacturing,and the vibration isolation performance is evaluated experimentally.The results show that the vibration isolation performance substantially enhances when the number of unit cells increases.More importantly,the ML-QZS meta-structure can be easily extended in the direction of vibration isolation when the unit cells are properly stacked.Hence,the ML-FQZS vibration isolation meta-structure should be a fascinating solution for highly efficient vibration isolation performance at low frequency.
基金support provided by the Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park Project(HZQB-KCZYB-2020030)the Research Grants Council of Hong Kong(Project No:AoE/M-402/20.)+1 种基金the Open Project of Yunnan Precious Metals Laboratory Co.,Ltd(YPML-2023050248)the Hong Kong Innovation and Technology Commission via the Hong Kong Branch of National Precious Metals Material Engineering Research Center.
文摘Solar steam generation(SSG)is widely regarded as one of the most sustainable technologies for seawater desalination.However,salt fouling severely compromises the evaporation performance and lifetime of evaporators,limiting their practical applications.Herein,we propose a hierarchical salt-rejection(HSR)strategy to prevent salt precipitation during long-term evaporation while maintaining a rapid evaporation rate,even in high-salinity brine.The salt diffusion process is segmented into three steps—insulation,branching diffusion,and arterial transport—that significantly enhance the salt-resistance properties of the evaporator.Moreover,the HSR strategy overcomes the tradeoff between salt resistance and evaporation rate.Consequently,a high evaporation rate of 2.84 kg m^(-2) h^(-1),stable evaporation for 7 days cyclic tests in 20 wt%NaCl solution,and continuous operation for 170 h in natural seawater under 1 sun illumination were achieved.Compared with control evaporators,the HSR evaporator exhibited a>54%enhancement in total water evaporation mass during 24 h continuous evaporation in 20 wt%salt water.Furthermore,a water collection device equipped with the HSR evaporator realized a high water purification rate(1.1 kg m^(-2) h^(-1)),highlighting its potential for agricultural applications.
基金National Nonprofit Institute Research Grant of CAF,No.CAFYBB2018ZA004,No.CAFYBB2023ZA009Fengyun Application Pioneering Project,No.FY-APP-ZX-2023.02。
文摘Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosystems.However,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain unclear.This study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–2020.Results indicated an annual mean WUE of 0.8088 gC/mm·m^(2)across the plateau,with a spatial gradient reflecting decrease from the southeast toward the northwest.Areas manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,respectively.Remarkably,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of increase.Environmental factors accounted for 70.79%of the variability in WUE.The leaf area index and temperature served as the major driving forces of WUE variation.
文摘Experimental methods,including mercury pressure,nuclear magnetic resonance(NMR)and core(wateroil)displacement,are used to examine the effects of high-multiple water injection(i.e.water injection with high injected pore volume)on rock properties,pore structure and oil displacement efficiency of an oilfield in the western South China Sea.The results show an increase in the permeability of rocks along with particle migration,an increase in the pore volume and the average pore throat radius,and enhanced heterogeneity after high-multiple water injection.Compared with normal water injection methods,a high-multiple water injection is more effective in improving the oil displacement efficiency.The degree of recovery increases faster in the early stage due to the expansion of the swept area,and the transition from oil-wet to water-wet.The degree of recovery increases less in the late stage due to various factors,including the enhancement of heterogeneity in the rocks.Considering both the economic aspect and the production limit of water flooding,it is recommended to adopt other technologies to further enhance oil recovery after 300 PV water injection.
基金financially supported by a National Research Foundation of Korea(NRF)grant funded by the Korean government(No.2016R1A3B1908249,RS202400407199).
文摘Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal conductivities of phase-change materials(PCMs)promote Joule heating dissi-pation.Repeated phase transitions also induce long-range atomic diffusion,limiting the durability.To address these challenges,phase-change heterostructure(PCH)devices that incorporate confinement sub-layers based on transition-metal dichalcogenide materials have been developed.In this study,we engi-neered a PCH device by integrating HfTe_(2),which has low thermal conductivity and excellent stability,into the PCM to realize PCRAM with enhanced thermal efficiency and structural stability.HEAT sim-ulations were conducted to validate the superior heat confinement in the programming region of the HfTe_(2)-based PCH device.Moreover,electrical measurements of the device demonstrated its outstanding performance,which was characterized by a low RESET current(∼1.6 mA),stable two-order ON/OFF ratio,and exceptional cycling endurance(∼2×10^(7)).The structural integrity of the HfTe_(2)confinement sub-layer was confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy.The material properties,including electrical conductivity,cohesive energy,and electronegativity,substantiated these findings.Collectively,these results revealed that the HfTe_(2)-based PCH device can achieve significant improvements in performance and reliability compared with conventional PCRAM devices.
