The creation and relaxation of double K-hole states 1s^(0)2s^(2)2p^(6)np(n≥3)of Ne^(1+)in the interaction with ultraintense ultrafast x-ray pulses are theoretically investigated.The x-ray photon energies are selected...The creation and relaxation of double K-hole states 1s^(0)2s^(2)2p^(6)np(n≥3)of Ne^(1+)in the interaction with ultraintense ultrafast x-ray pulses are theoretically investigated.The x-ray photon energies are selected so that x-rays first photoionize1s^(22)s^(22)p^(6) of a neon atom to create a single K-hole state of 1s2s^(22)p^(6) of Ne^(1+),which is further excited resonantly to double K-hole states of ls^(0)2s^(2)2p^(6)np(n≥3).A time-dependent rate equation is used to investigate the creation and relaxation processes of 1s^(0)2s^(2)2p^(6)np,where the primary microscopic atomic processes including photoexcitation,spontaneous radiation,photoionization and Auger decay are considered.The calculated Auger electron energy spectra are compared with recent experimental results,which shows good agreement.The relative intensity of Auger electrons is very sensitive to the photon energy and bandwidth of x-ray pulses,which could be used as a diagnostic tool for x-ray free electron laser and atom experiments.展开更多
Nitrogen(N) is an essential nutrient for food production. The rapid increase in population requires high inputs of N to meet the growing food demand. If not managed well, the substantial loss of N from the food system...Nitrogen(N) is an essential nutrient for food production. The rapid increase in population requires high inputs of N to meet the growing food demand. If not managed well, the substantial loss of N from the food system has multiple impacts on grain yield, air and water pollution, and the economic benefits of agricultural. Multi-objective(food security, environmental sustainability and economic sustainability) synergistic consideration of N management in the food system is still lacking. This study employed strategies for optimizing N management in the food system, using Quzhou County as a typical example on the North China Plain. Firstly, a food chain approach was adopted to understand drivers and reasons behind N losses from the food system.Secondly, a top-down approach was used to define multi-objective N management, taking into consideration food security, environmental sustainability and economic sustainability. Multi-objective N management aims to reduce N losses to the environment and increase N use efficiencies,while simultaneously increasing yields and economic benefits. Thirdly, 3R(reduce-retain-recycle) N management strategies were identified for specific crops and animals through a bottom-up approach and then analyzed the potential of these strategies to achieve the multi-objectives. Finally, there is a discussion of how to engage different stakeholders to promote the technologies implementation. This study provides new insights into the synergistic achievement of multi-objective N management in the food system and the development of environmentally-friendly agriculture.展开更多
Rutaecarpine, an active component of the traditional Chinese medicine Tetradium ruticarpum, has been shown to improve myocardial ischemia repeffusion injury. Because both cardiovascular and cerebrovascular diseases ar...Rutaecarpine, an active component of the traditional Chinese medicine Tetradium ruticarpum, has been shown to improve myocardial ischemia repeffusion injury. Because both cardiovascular and cerebrovascular diseases are forms of ischemic vascular disease, they are closely related. We hypothesized that rutaecarpine also has neuroprotective effects on cerebral ischemia reperfusion injury. A cerebral ischemia reperfusion model was established after 84, 252 and 504 pg/kg rutae- carpine were given to mice via intrapedtoneal injection, daily for 7 days. Results of the step through test, 2,3,5-triphenyl tetrazolium chloride dyeing and oxidative stress indicators showed that rutae- carpine could improve learning and memory ability, neurological symptoms and reduce infarction volume and cerebral water content in mice with cerebral ischemia reperfusion injury. Rutaecarpine could significantly decrease the malondialdehyde content and increase the activities of superoxide dismutase and glutathione peroxidase in mouse brain. Therefore, rutaecarpine could improve neu- rological function following injury induced by cerebral ischemia reperfusion, and the mechanism of this improvement may be associated with oxidative stress. These results verify that rutaecarpine has neuroprotective effects on cerebral ischemia reperfusion in mice.展开更多
Previous studies have shown that chrysophanol protects against learning and memory impairments in lead-exposed adult mice. In the present study, we investigated whether chrysophanol can alleviate learning and memory d...Previous studies have shown that chrysophanol protects against learning and memory impairments in lead-exposed adult mice. In the present study, we investigated whether chrysophanol can alleviate learning and memory dysfunction and hippocampal neuronal injury in lead-exposed neonatal mice. At the end of lactation, chrysophanol(0.1, 1.0, 10.0 mg/kg) was administered to the neonatal mice by intraperitoneal injection for 15 days. Chrysophanol significantly alleviated injury to hippocampal neurons and improved learning and memory abilities in the lead-poisoned neonatal mice. Chrysophanol also significantly decreased lead content in blood, brain, heart, spleen, liver and kidney in the lead-exposed neonatal mice. The levels of malondialdehyde in the brain, liver and kidney were significantly reduced, and superoxide dismutase and glutathione peroxidase activities were significantly increased after chrysophanol treatment. Collectively, these findings indicate that chrysophanol can significantly reduce damage to hippocampal neurons in lead-exposed neonatal mice.展开更多
Aluminum alloys have drawn considerable attention in the area of automotive lightweight.High strength aluminum alloys are usually deformed at elevated temperatures due to their poor formability at room temperature.In ...Aluminum alloys have drawn considerable attention in the area of automotive lightweight.High strength aluminum alloys are usually deformed at elevated temperatures due to their poor formability at room temperature.In this work,the yield behavior of 7075 aluminum alloy in T6 temper(AA7075-T6)within the temperature ranging from 25°C to 230°C was investigated.Uniaxial and biaxial tensile tests with the aid of induction heating system were performed to determine the stress vs.strain curves and the yield loci of AA7075-T6 at elevated temperatures,respectively.Von Mises,Hill48 and Yld2000-2d yield criteria were applied to predicting yield loci which were compared with experimentally measured yield loci of the AA7075-T6.Results show that yield stress corresponding to the same equivalent plastic strain decreases with increasing temperature within the investigated temperature range and the shape of yield loci evolves nearly negligibly.The experimental yield locus expands with an increase of equivalent plastic strain at the same temperature and the work hardening rate of AA7075-T6 exhibits obvious stress-state-dependency.The nonquadratic Yld2000-2d yield criterion describes the yield surfaces of AA7075-T6 more accurately than the quadratic von Mises and Hill48 yield criteria,and an exponent of 14 in the Yld2000-2d yield function gives the optimal predictions for the AA7075-T6 at all investigated temperatures.展开更多
Accurate knowledge of the equation of state(EOS)of deuterium–tritium(DT)mixtures is critically important for inertial confinement fusion(ICF).Although the study of EOS is an old topic,there is a longstanding lack of ...Accurate knowledge of the equation of state(EOS)of deuterium–tritium(DT)mixtures is critically important for inertial confinement fusion(ICF).Although the study of EOS is an old topic,there is a longstanding lack of global accurate EOS data for DT within a unified theoretical framework.DT fuel goes through very wide ranges of density and temperature from a cold condensed state to a hot dense plasma where ions are in a moderately or even strongly coupled state and electrons are in a partially or strongly degenerate state.The biggest challenge faced when using first-principles methods for obtaining accurate EOS data for DT fuel is the treatment of electron–ion interactions and the extremely high computational cost at high temperatures.In the present work,we perform extensive state-of-the-art ab initio quantum Langevin molecular dynamics simulations to obtain EOS data for DT mixtures at densities from 0.1 g/cm3 to 2000 g/cm3 and temperatures from 500 K to 2000 eV,which are relevant to ICF processes.Comparisons with average-atom molecular dynamics and orbital-free molecular dynamics simulations show that the ionic strong-coupling effect is important for determining the whole-range EOS.This work can supply accurate EOS data forDTmixtures within a unified ab initio framework,as well as providing a benchmark for various semiclassical methods.展开更多
The equation of states,diffusions,and viscosities of strongly coupled Fe at 80 and 240 eV with densities from 1.6 to 40 g/cm^(3) are studied by orbital-free molecular dynamics,classical molecular dynamics with a corre...The equation of states,diffusions,and viscosities of strongly coupled Fe at 80 and 240 eV with densities from 1.6 to 40 g/cm^(3) are studied by orbital-free molecular dynamics,classical molecular dynamics with a corrected Yukawa potential and compared with the results from average atom model.A new local pseudopotential is generated for orbital free calculations.For low densities,the Yukawa model captures the correct ionic interaction behavior around the first peak of the radial distribution function(RDF),thus it gives correct RDFs and transport coefficients.For higher densities,the scaled transformation of the Yukawa potential or adding a short range repulsion part to the Yukawa potential can give correct RDFs and transport coefficients.The corrected potentials are further validated by the force matching method.展开更多
High-Zmaterials exhibit a broad range of variation of the charge state in the hot dense regime,and so ionic structures becomecomplexwith increasing density and temperature owing to ionization.Taking high-Z uranium as ...High-Zmaterials exhibit a broad range of variation of the charge state in the hot dense regime,and so ionic structures becomecomplexwith increasing density and temperature owing to ionization.Taking high-Z uranium as example,we study its electronic and ionic structures in the hot dense regime by combining an average-atommodelwith the hypernetted chain approximation.The electronic structure is described by solving theDirac equation,taking account of relativistic effects,including broadening of the energy levels,and the effect of other ions via correlation functions.On the basis of the electronic distribution around a nucleus,the ion pair potential is constructed using the modified Gordon–Kim model in the frame of temperaturedependent density functional theory.Because of the presence of ion–ion strong coupling,the bridge function is included in the hypernetted chain approximation,whichis usedto calculate the correlation functions.To take account of the influenceon transportpropertiesof the strong correlation of electrons with highly charged ions,we perform both classical and Langevin molecular dynamics simulations to determine ion self-diffusion coefficients and the shear viscosity,using theGreen–Kubo relation and an ion–ion pair potential with good convergence.We show that the influence of electron–ion collisions on transport properties becomes more important as the free electron density increases owing to thermal ionization.展开更多
Objective: To study the protective effect of ruanganyin on the liver of HBV transgenic mice. Methods: 50 half HBV transgenic mice, male and female, were randomly divided into treatment group (high, medium and low dose...Objective: To study the protective effect of ruanganyin on the liver of HBV transgenic mice. Methods: 50 half HBV transgenic mice, male and female, were randomly divided into treatment group (high, medium and low dose Ruanganyin), model group, positive control group (entecavir dispersible tablet) and 10 non HBV transgenic mice as blank control. The mice were killed after 4 weeks of drug intervention.The serum levels of ALT, AST, TBIL, LN, HA, IV-C and PCIII were observed. Results: (1) compared with the blank control group, the ALT,AST and TBIL levels in the model group were significantly higher than those in the blank control group (P < 0.01);compared with the model group, the ALT, AST and TBIL levels in the high-dose group of ruanganyin after treatment were significantly lower than those in the model group (P<0.01/P<0.05);the ALT, AST and TBIL levels in the positive control group were lower than those in the model group (P<0.01/P<0.05) There was no significant difference in ALT, AST and TBIL levels between the two groups (P>0.05). (2) Compared with the blank control group, the level of LN, HA, IV-C and PCIII in the model group was significantly higher than that in the blank control group (P<0.01);compared with the model group, the level of LN, HA and IV-C in the high-dose group and the positive control group after treatment was significantly lower than that in the model group (P<0.01);the level of PCIII in the high-dose group and the positive control group after treatment was significantly lower than that in the model group (P<0.01);There was no significant difference in LN, HA, IV-C and PCIII levels between the two groups (P> 0.05). Conclusion: Chinese medicine Ruanganyin has the effects of protecting liver, reducing enzyme and anti fibrosis, but its mechanism of anti fibrosis needs further study.展开更多
Reconciling the tasks of producing adequate amounts of nutritious food for the increasing global population while preserving the environment and natural ecosystems simultaneously is an enormous challenge. The concept ...Reconciling the tasks of producing adequate amounts of nutritious food for the increasing global population while preserving the environment and natural ecosystems simultaneously is an enormous challenge. The concept of agriculture green development(AGD) and the necessary governmental policies were developed to address the aforementioned challenge in China and to help achieve the related global sustainable development goals. Agriculture green development emphasizes the synergy between green and development;current agriculture has to transform from the intensive farming with high inputs, high environmental impacts and low resource-use efficiency to a more sustainable agriculture, in order to ensure an adequate supply of nutritious food while delivering environmental integrity, improved economic profitability,and social equity. A research program on AGD was established by China Agricultural University with four research themes, namely: green crop production, green integrated crop-animal production, green food and industry,and green ecological environment and ecosystem services, to provide a scientific basis for future developments and to facilitate the implementation of AGD in practice. AGD requires a multistakeholder approach, fueled by innovative and interdisciplinary research. Joint actions have to be taken by governments, farmers, supply industries, consumers, educators, extension services and researchers to support AGD. This requires strong coordination and public awareness campaigns. This review presents the progress that has been made over the past 5 years and makes recommendations for more research and development, in order to better deliver agricultural green and sustainable development on national and international scales.展开更多
Balancing ecological preservation with sustainable agricultural practices is a global issue. Erhai Lake has felt this challenge keenly. To address it, in 2022, a Science and Technology Backyards(STBs) project was laun...Balancing ecological preservation with sustainable agricultural practices is a global issue. Erhai Lake has felt this challenge keenly. To address it, in 2022, a Science and Technology Backyards(STBs) project was launched in Gusheng Village. The goal of this is to care for the environment while ensuring that farms and farmers can thrive sustainably. The uniqueness of the Erhai STB arises from its interdisciplinary integration, encompassing fields such as ecology, agronomy and social science, resulting in specifically-designed solutions for the Erhai context. While this model aligns with broader STB paradigms, its distinctive edge lies in technological innovation and robust support mechanisms for local agricultural stakeholders. This paper describes the methodology and outcomes of the STB initiative, highlighting its pivotal role in spearheading sustainable transition in Erhai. Preliminary findings underscore the potential of the STB model as an efficacious tool for harmonizing environmental conservation and agricultural practices, that are both financially and environmentally sustainable, rendering it a potential model for comparable regions in China and other counties.展开更多
China has initiated a green transformation plan in 2015, which was soon applied to agriculture, known as the agriculture green development(AGD)initiative, with the goals of achieving food security, high resource use e...China has initiated a green transformation plan in 2015, which was soon applied to agriculture, known as the agriculture green development(AGD)initiative, with the goals of achieving food security, high resource use efficiency, and an ecofriendly environment. To assess the agricultural transformation from 1997 to 2020, this paper proposes a national-scale indicator system consisting three dimensions(socioeconomic, food production and eco-environmental) and ten sub-dimensions to quantify the AGD score.This study showed that AGD score in China was at a moderate level during 1997–2010, scoring 40 out of 100. During this stage, decreased scores in the sub-dimensions of resource consumption, environmental quality, and environmental cost have offset the improvement in the socioeconomic dimension, resulting in fluctuated scores around 40. In the second stage(2011–2020), China's AGD score improved but still at moderate level, scoring an average of 46.3, with each dimension increasing by 5.3%–25.0%. These results indicate that China has made progress in the agricultural transformation, transitioning from conceptualization to actions through the implementation of various policies and projects. However, the study emphasizes the need for more effort to address the insufficient and unbalanced development, along with the growing eco-environmental challenges, especially the trade-offs among dimensions.展开更多
Under the extremely cold climatic condition,crops have to survive severe heat stress conditions,even if they are being kept in greenhouses.In the winter and spring of North China,the air and soil temperature is low in...Under the extremely cold climatic condition,crops have to survive severe heat stress conditions,even if they are being kept in greenhouses.In the winter and spring of North China,the air and soil temperature is low inside the greenhouse,and when using a traditional heating system,the energy consumption is high.This paper reports on a study of different design solutions for a root zone heating system based on a kind of low temperature radiation material.Root zone heating systems offer increasing crop quality and productivity.A novel type of heat preservation and root zone heating system was applied in greenhouse seedling.And through multiple experiments,the effect of the root zone heating system on the ambient environment and seedbed surface was studied,and the heat preservation effect and heating uniformity were discussed.Results show that single-layer film covering on the root zone heating system can make the average temperature at night increase 1°C.And the average seedbed surface and substrate temperature can increase 11.3°C and 5.2°C,respectively.In conclusion,the root zone heating system can effectively improve the environmental temperature of seedling and the uniformity of heating is high,which provides a strong guarantee for high-quality seedling cultivation.展开更多
Heating greenhouse is indispensable for plant development particularly in winter when the air temperature is lower.In that sense,root zone heating is more energy-saving than traditional air heating.The current work wa...Heating greenhouse is indispensable for plant development particularly in winter when the air temperature is lower.In that sense,root zone heating is more energy-saving than traditional air heating.The current work was devoted to the study of the effect of two root zone heating systems based on carbon crystal electrothermal film and low temperature hot water pipe on the microclimate and tomato yield in solar greenhouse.And their performance was tested in the coldest period of winter in Yongqing County of Hebei Province.The results showed that the use of root zone heating system can improve the average substrate temperature by 6.8℃.This microclimate improvement had a positive impact on tomato production.The output per square meter has increased by 19%compared to the unheated.It was also noted that the presence of root zone heating leads to a decrease in the development of disease in heated areas.Based on these results,the root zone heating system can be an effective method of improving the environmental temperature of crop plant,which is of great significance for increasing crop yield.展开更多
6016-T4 aluminum alloy and DP490 steel were systematically tested under 24 proportional loading paths,including uniaxial tensile tests with a 15°increment,uniaxial compressive and simple shear tests with a 45...6016-T4 aluminum alloy and DP490 steel were systematically tested under 24 proportional loading paths,including uniaxial tensile tests with a 15°increment,uniaxial compressive and simple shear tests with a 45°increment,and biaxial tensile tests using cruciform specimens.Cruciform specimens in the rolling/transverse and 45°/135°sampling directions were tested with seven and four different stress ra-tios,respectively.The normal and diagonal planes plastic work contours and the yield stresses under uniaxial tension and compression were measured to investigate the anisotropic yield.Meanwhile,the normal and diagonal planes directions of plastic strain rate and the rα-values under uniaxial tension and compression were characterized to confirm the plastic flow.Several existing asymmetric yield crite-ria under the associated and non-associated flow rules were comprehensively evaluated to describe the asymmetric plastic anisotropy of 6016-T4 aluminum alloy and DP490 steel.The results suggest that in the investigated yield criteria,the non-associated models can predict the tension and compression asym-metry of materials more accurately than the associated models,and the function of stress triaxiality can more effectively describe the asymmetric yield behavior than the first stress invariant.In addition,the pure shear stress states are helpful in assessing the validity and applicability of advanced asymmetric yield stress functions,and the inspection of diagonal plane plastic work contours containing more pure shear stress states should prioritized over that of normal plane plastic work contours.The evaluation of plastic potential functions should not only consider the prediction accuracy of the normal plane di-rections of plastic strain rate,but also further check the diagonal plane directions of plastic strain rate.Expressing mechanical properties as a function of equivalent plastic strain to calibrate parameters of the yield criterion allows the continuous capture of anisotropic evolution of the asymmetric yield surface and the changes in the asymmetric plastic potential surface.展开更多
Pollution of high-altitude lake basins by agriculture and rural activities,and the control of this pollution,have received increasing attention from academic research and government policy in China.Series of restricti...Pollution of high-altitude lake basins by agriculture and rural activities,and the control of this pollution,have received increasing attention from academic research and government policy in China.Series of restrictions and regulations have been implemented to protect the surface,water quality.These restrictions and regulations have greatly impacted and transformed the agricultural systems and rural livelihoods surrounding these lake basins.Using Erhai Lake basin in Yunnan Province as a case study,three main challenges were identified for concurrently decreasing pollution in the lake and increasing farmer income.It is contended that scientifically-sound environmental protection policies and agricultural green development practices are key to reversing the current situation.This will help to protect the lake from pollution while smallholder farmers will be able to produce healthy food in an environmentally sustainable manner,and with a fair remuneration for all the services farmers providetothe society.展开更多
Lightweight sheet metals are highly desirable for automotive applications due to their exceptional strength-to-density ratio.An accurate description of the pronounced plastic anisotropy exhibited by these materials in...Lightweight sheet metals are highly desirable for automotive applications due to their exceptional strength-to-density ratio.An accurate description of the pronounced plastic anisotropy exhibited by these materials in finite element analysis requires advanced plasticity models.In recent years,significant efforts have been devoted to developing plasticity models and numeri-cal analysis methods based on the non-associated flow rule(non-AFR).In this work,a newly proposed coupled quadratic and non-quadratic model under non-AFR is utilized to comprehensively investigate the non-associated and non-quadratic characteristics during the yielding of three lightweight sheet metals,i.e.,dual-phase steel DP980,TRIP-assisted steel QP980,and aluminum alloy AA5754-O.These materials are subjected to various proportional loading paths,including uniaxial tensile tests with a 15°increment,uniaxial compressive tests with a 45°increment,in-plane torsion tests,and biaxial tensile tests using laser-deposited arm-strengthened cruciform specimens.Results show that the non-AFR approach provides an effective means for accurately modeling the yield behavior,including yield stresses and the direction of plastic strain rates,simultaneously,utilizing two separate functions and a simple calibration procedure.The introduction of the non-quadratic plastic potential reduces the average errors in angle when predicting plastic strain directions by the quadratic plastic potential function.Specifically,for DP980,the average error is reduced from 3.1°to 0.9°,for QP980 it is reduced from 6.1°to 3.9°,and for AA5754-O it is reduced from 7.0°to 0.2°.This highlights the importance of considering the non-quadratic characteristic in plasticity modeling,especially for aluminum alloys such as AA5754-O.展开更多
Realizing sustainable development has become a global priority.This holds,in particular,for agriculture.Recently,the United Nations launched the Sustainable Development Goals(SDGs),and the Nineteenth National People’...Realizing sustainable development has become a global priority.This holds,in particular,for agriculture.Recently,the United Nations launched the Sustainable Development Goals(SDGs),and the Nineteenth National People’s Congress has delivered a national strategy for sustainable development in China—realizing green development.The overall objective of Agriculture Green Development(AGD)is to coordinate"green"with"development"to realize the transformation of current agriculture with high resource consumption and high environmental costs into a green agriculture and countryside with high productivity,high resource use efficiency and low environmental impact.This is a formidable task,requiring joint efforts of government,farmers,industry,educators and researchers.The innovative concept for AGD will focus on reconstructing the whole crop-animal production and food production-consumption system,with the emphasis on high thresholds for environmental standards and food quality as well as enhanced human well-being.This paper addresses the significance,challenges,framework,pathways and potential solutions for realizing AGD in China,and highlights the potential changes that will lead to a more sustainable agriculture in the future.Proposals include interdisciplinary innovations,whole food chain improvement and regional solutions.The implementation of AGD in China will provide important implications for the countries in developmental transition,and contribute to global sustainable development.展开更多
As the demand for livestock products continues to increase in China,so too does the challenge of managing increasing quantities of manure.Urgent action is needed to control point source(housing,storage and processing)...As the demand for livestock products continues to increase in China,so too does the challenge of managing increasing quantities of manure.Urgent action is needed to control point source(housing,storage and processing)and diffuse(field application)pollution and improve the utilization of manure nutrients and organic matter.Here,we review strategies to improve management at each stage of the manure management chain and at different scales.Many strategies require infrastructure investment,e.g.,for containment of all manure fractions.Engineering solutions are needed to develop advanced composting systems with lower environmental footprints and design more efficient nutrient stripping technologies.At the field-scale,there is an urgent need to develop a manure nutrient recommendation system that accounts for the range of manure types,cropping systems,soils and climates throughout China.At the regional scale,coordinated planning is necessary to promote recoupling of livestock and cropping systems,and reduce nutrient accumulation in regions with little available landbank,while minimizing the risk of pollution swapping from one region to another.A range of stakeholders are needed to support the step change and innovation required to improve manure management,reduce reliance on inorganic fertilizers,and generate new business opportunities.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12074430 and 11974423)。
文摘The creation and relaxation of double K-hole states 1s^(0)2s^(2)2p^(6)np(n≥3)of Ne^(1+)in the interaction with ultraintense ultrafast x-ray pulses are theoretically investigated.The x-ray photon energies are selected so that x-rays first photoionize1s^(22)s^(22)p^(6) of a neon atom to create a single K-hole state of 1s2s^(22)p^(6) of Ne^(1+),which is further excited resonantly to double K-hole states of ls^(0)2s^(2)2p^(6)np(n≥3).A time-dependent rate equation is used to investigate the creation and relaxation processes of 1s^(0)2s^(2)2p^(6)np,where the primary microscopic atomic processes including photoexcitation,spontaneous radiation,photoionization and Auger decay are considered.The calculated Auger electron energy spectra are compared with recent experimental results,which shows good agreement.The relative intensity of Auger electrons is very sensitive to the photon energy and bandwidth of x-ray pulses,which could be used as a diagnostic tool for x-ray free electron laser and atom experiments.
基金supported by the National Natural Science Foundation of China (42175137)the Major Science and Technology Project of Yunnan Province (202202AE090034)+2 种基金the China Scholarship Council (201913043)Hainan Universitythe High-level Team Project of China Agricultural University。
文摘Nitrogen(N) is an essential nutrient for food production. The rapid increase in population requires high inputs of N to meet the growing food demand. If not managed well, the substantial loss of N from the food system has multiple impacts on grain yield, air and water pollution, and the economic benefits of agricultural. Multi-objective(food security, environmental sustainability and economic sustainability) synergistic consideration of N management in the food system is still lacking. This study employed strategies for optimizing N management in the food system, using Quzhou County as a typical example on the North China Plain. Firstly, a food chain approach was adopted to understand drivers and reasons behind N losses from the food system.Secondly, a top-down approach was used to define multi-objective N management, taking into consideration food security, environmental sustainability and economic sustainability. Multi-objective N management aims to reduce N losses to the environment and increase N use efficiencies,while simultaneously increasing yields and economic benefits. Thirdly, 3R(reduce-retain-recycle) N management strategies were identified for specific crops and animals through a bottom-up approach and then analyzed the potential of these strategies to achieve the multi-objectives. Finally, there is a discussion of how to engage different stakeholders to promote the technologies implementation. This study provides new insights into the synergistic achievement of multi-objective N management in the food system and the development of environmentally-friendly agriculture.
基金financially supported by Zhangjiakou Science and Technology Commission Foundation,No.1021095Dthe Hebei North University Foundation,No.Q2010018
文摘Rutaecarpine, an active component of the traditional Chinese medicine Tetradium ruticarpum, has been shown to improve myocardial ischemia repeffusion injury. Because both cardiovascular and cerebrovascular diseases are forms of ischemic vascular disease, they are closely related. We hypothesized that rutaecarpine also has neuroprotective effects on cerebral ischemia reperfusion injury. A cerebral ischemia reperfusion model was established after 84, 252 and 504 pg/kg rutae- carpine were given to mice via intrapedtoneal injection, daily for 7 days. Results of the step through test, 2,3,5-triphenyl tetrazolium chloride dyeing and oxidative stress indicators showed that rutae- carpine could improve learning and memory ability, neurological symptoms and reduce infarction volume and cerebral water content in mice with cerebral ischemia reperfusion injury. Rutaecarpine could significantly decrease the malondialdehyde content and increase the activities of superoxide dismutase and glutathione peroxidase in mouse brain. Therefore, rutaecarpine could improve neu- rological function following injury induced by cerebral ischemia reperfusion, and the mechanism of this improvement may be associated with oxidative stress. These results verify that rutaecarpine has neuroprotective effects on cerebral ischemia reperfusion in mice.
基金financially supported by the Science and Technology Commission Foundation of Zhangjiakou City,No.1021098Dthe Medical Scientific Research Project of Health Bureau of Hebei Province,No.20100144+2 种基金the Natural Science Foundation of Hebei Province,No.H2012405016the Innovative Talents Project of Hebei North University,No.CXRC1325the Major Projects of Hebei North University,No.ZD201310
文摘Previous studies have shown that chrysophanol protects against learning and memory impairments in lead-exposed adult mice. In the present study, we investigated whether chrysophanol can alleviate learning and memory dysfunction and hippocampal neuronal injury in lead-exposed neonatal mice. At the end of lactation, chrysophanol(0.1, 1.0, 10.0 mg/kg) was administered to the neonatal mice by intraperitoneal injection for 15 days. Chrysophanol significantly alleviated injury to hippocampal neurons and improved learning and memory abilities in the lead-poisoned neonatal mice. Chrysophanol also significantly decreased lead content in blood, brain, heart, spleen, liver and kidney in the lead-exposed neonatal mice. The levels of malondialdehyde in the brain, liver and kidney were significantly reduced, and superoxide dismutase and glutathione peroxidase activities were significantly increased after chrysophanol treatment. Collectively, these findings indicate that chrysophanol can significantly reduce damage to hippocampal neurons in lead-exposed neonatal mice.
基金Supported by National Natural Science Foundation of China(Grant No.51805375).
文摘Aluminum alloys have drawn considerable attention in the area of automotive lightweight.High strength aluminum alloys are usually deformed at elevated temperatures due to their poor formability at room temperature.In this work,the yield behavior of 7075 aluminum alloy in T6 temper(AA7075-T6)within the temperature ranging from 25°C to 230°C was investigated.Uniaxial and biaxial tensile tests with the aid of induction heating system were performed to determine the stress vs.strain curves and the yield loci of AA7075-T6 at elevated temperatures,respectively.Von Mises,Hill48 and Yld2000-2d yield criteria were applied to predicting yield loci which were compared with experimentally measured yield loci of the AA7075-T6.Results show that yield stress corresponding to the same equivalent plastic strain decreases with increasing temperature within the investigated temperature range and the shape of yield loci evolves nearly negligibly.The experimental yield locus expands with an increase of equivalent plastic strain at the same temperature and the work hardening rate of AA7075-T6 exhibits obvious stress-state-dependency.The nonquadratic Yld2000-2d yield criterion describes the yield surfaces of AA7075-T6 more accurately than the quadratic von Mises and Hill48 yield criteria,and an exponent of 14 in the Yld2000-2d yield function gives the optimal predictions for the AA7075-T6 at all investigated temperatures.
基金This work was supported by the Science Challenge Project under Grant No.TZ2016001the National Key R&D Program of China under Grant No.2017YFA0403200+1 种基金the National Natural Science Foundation of China under Grant Nos.11874424 and 11774429the NSAF under Grant No.U1830206.All calculations were carried out at the Research Center of Supercomputing Applications at NUDT.
文摘Accurate knowledge of the equation of state(EOS)of deuterium–tritium(DT)mixtures is critically important for inertial confinement fusion(ICF).Although the study of EOS is an old topic,there is a longstanding lack of global accurate EOS data for DT within a unified theoretical framework.DT fuel goes through very wide ranges of density and temperature from a cold condensed state to a hot dense plasma where ions are in a moderately or even strongly coupled state and electrons are in a partially or strongly degenerate state.The biggest challenge faced when using first-principles methods for obtaining accurate EOS data for DT fuel is the treatment of electron–ion interactions and the extremely high computational cost at high temperatures.In the present work,we perform extensive state-of-the-art ab initio quantum Langevin molecular dynamics simulations to obtain EOS data for DT mixtures at densities from 0.1 g/cm3 to 2000 g/cm3 and temperatures from 500 K to 2000 eV,which are relevant to ICF processes.Comparisons with average-atom molecular dynamics and orbital-free molecular dynamics simulations show that the ionic strong-coupling effect is important for determining the whole-range EOS.This work can supply accurate EOS data forDTmixtures within a unified ab initio framework,as well as providing a benchmark for various semiclassical methods.
基金This work is supported by the National Basic Research Program of China(973 Program)under grant no.2013CB922203the National NSFC under grant Nos.11422432 and 11774429+1 种基金Science Challenge Project under grant no.JCKY2016212A501the Advanced Research Foundation of National University of Defense Technology under grant no.JQ14-02-01.
文摘The equation of states,diffusions,and viscosities of strongly coupled Fe at 80 and 240 eV with densities from 1.6 to 40 g/cm^(3) are studied by orbital-free molecular dynamics,classical molecular dynamics with a corrected Yukawa potential and compared with the results from average atom model.A new local pseudopotential is generated for orbital free calculations.For low densities,the Yukawa model captures the correct ionic interaction behavior around the first peak of the radial distribution function(RDF),thus it gives correct RDFs and transport coefficients.For higher densities,the scaled transformation of the Yukawa potential or adding a short range repulsion part to the Yukawa potential can give correct RDFs and transport coefficients.The corrected potentials are further validated by the force matching method.
文摘High-Zmaterials exhibit a broad range of variation of the charge state in the hot dense regime,and so ionic structures becomecomplexwith increasing density and temperature owing to ionization.Taking high-Z uranium as example,we study its electronic and ionic structures in the hot dense regime by combining an average-atommodelwith the hypernetted chain approximation.The electronic structure is described by solving theDirac equation,taking account of relativistic effects,including broadening of the energy levels,and the effect of other ions via correlation functions.On the basis of the electronic distribution around a nucleus,the ion pair potential is constructed using the modified Gordon–Kim model in the frame of temperaturedependent density functional theory.Because of the presence of ion–ion strong coupling,the bridge function is included in the hypernetted chain approximation,whichis usedto calculate the correlation functions.To take account of the influenceon transportpropertiesof the strong correlation of electrons with highly charged ions,we perform both classical and Langevin molecular dynamics simulations to determine ion self-diffusion coefficients and the shear viscosity,using theGreen–Kubo relation and an ion–ion pair potential with good convergence.We show that the influence of electron–ion collisions on transport properties becomes more important as the free electron density increases owing to thermal ionization.
文摘Objective: To study the protective effect of ruanganyin on the liver of HBV transgenic mice. Methods: 50 half HBV transgenic mice, male and female, were randomly divided into treatment group (high, medium and low dose Ruanganyin), model group, positive control group (entecavir dispersible tablet) and 10 non HBV transgenic mice as blank control. The mice were killed after 4 weeks of drug intervention.The serum levels of ALT, AST, TBIL, LN, HA, IV-C and PCIII were observed. Results: (1) compared with the blank control group, the ALT,AST and TBIL levels in the model group were significantly higher than those in the blank control group (P < 0.01);compared with the model group, the ALT, AST and TBIL levels in the high-dose group of ruanganyin after treatment were significantly lower than those in the model group (P<0.01/P<0.05);the ALT, AST and TBIL levels in the positive control group were lower than those in the model group (P<0.01/P<0.05) There was no significant difference in ALT, AST and TBIL levels between the two groups (P>0.05). (2) Compared with the blank control group, the level of LN, HA, IV-C and PCIII in the model group was significantly higher than that in the blank control group (P<0.01);compared with the model group, the level of LN, HA and IV-C in the high-dose group and the positive control group after treatment was significantly lower than that in the model group (P<0.01);the level of PCIII in the high-dose group and the positive control group after treatment was significantly lower than that in the model group (P<0.01);There was no significant difference in LN, HA, IV-C and PCIII levels between the two groups (P> 0.05). Conclusion: Chinese medicine Ruanganyin has the effects of protecting liver, reducing enzyme and anti fibrosis, but its mechanism of anti fibrosis needs further study.
基金financially supported by a project of Beijing’s Top-Precision-Advanced Disciplinesthe CSC-AGD PhD Program from China Scholarship Council+3 种基金the National Key Research and Development Program of China (2023YFD1901500, 2023YFD1901502)the Key Consulting Project of the Chinese Academy of EngineeringYunnan Rural Revitalization Science and Technology Project, PR China (202104BI090004)the 2115 Talent Development Program of China Agricultural University。
文摘Reconciling the tasks of producing adequate amounts of nutritious food for the increasing global population while preserving the environment and natural ecosystems simultaneously is an enormous challenge. The concept of agriculture green development(AGD) and the necessary governmental policies were developed to address the aforementioned challenge in China and to help achieve the related global sustainable development goals. Agriculture green development emphasizes the synergy between green and development;current agriculture has to transform from the intensive farming with high inputs, high environmental impacts and low resource-use efficiency to a more sustainable agriculture, in order to ensure an adequate supply of nutritious food while delivering environmental integrity, improved economic profitability,and social equity. A research program on AGD was established by China Agricultural University with four research themes, namely: green crop production, green integrated crop-animal production, green food and industry,and green ecological environment and ecosystem services, to provide a scientific basis for future developments and to facilitate the implementation of AGD in practice. AGD requires a multistakeholder approach, fueled by innovative and interdisciplinary research. Joint actions have to be taken by governments, farmers, supply industries, consumers, educators, extension services and researchers to support AGD. This requires strong coordination and public awareness campaigns. This review presents the progress that has been made over the past 5 years and makes recommendations for more research and development, in order to better deliver agricultural green and sustainable development on national and international scales.
基金supported by the National Key R&D Program of China (2022YFD1901504-02)the Yunnan Science and Technology Program (202202AE090034-05) to Kemo Jin。
文摘Balancing ecological preservation with sustainable agricultural practices is a global issue. Erhai Lake has felt this challenge keenly. To address it, in 2022, a Science and Technology Backyards(STBs) project was launched in Gusheng Village. The goal of this is to care for the environment while ensuring that farms and farmers can thrive sustainably. The uniqueness of the Erhai STB arises from its interdisciplinary integration, encompassing fields such as ecology, agronomy and social science, resulting in specifically-designed solutions for the Erhai context. While this model aligns with broader STB paradigms, its distinctive edge lies in technological innovation and robust support mechanisms for local agricultural stakeholders. This paper describes the methodology and outcomes of the STB initiative, highlighting its pivotal role in spearheading sustainable transition in Erhai. Preliminary findings underscore the potential of the STB model as an efficacious tool for harmonizing environmental conservation and agricultural practices, that are both financially and environmentally sustainable, rendering it a potential model for comparable regions in China and other counties.
基金funded by Yunnan Provincial Major Science and Technology Special Project (202102AE090030)the Strategic Consulting Project of Chinese Academy of Engineering (2022-XY-49)+1 种基金China Scholarship Council (201913043)Hainan University。
文摘China has initiated a green transformation plan in 2015, which was soon applied to agriculture, known as the agriculture green development(AGD)initiative, with the goals of achieving food security, high resource use efficiency, and an ecofriendly environment. To assess the agricultural transformation from 1997 to 2020, this paper proposes a national-scale indicator system consisting three dimensions(socioeconomic, food production and eco-environmental) and ten sub-dimensions to quantify the AGD score.This study showed that AGD score in China was at a moderate level during 1997–2010, scoring 40 out of 100. During this stage, decreased scores in the sub-dimensions of resource consumption, environmental quality, and environmental cost have offset the improvement in the socioeconomic dimension, resulting in fluctuated scores around 40. In the second stage(2011–2020), China's AGD score improved but still at moderate level, scoring an average of 46.3, with each dimension increasing by 5.3%–25.0%. These results indicate that China has made progress in the agricultural transformation, transitioning from conceptualization to actions through the implementation of various policies and projects. However, the study emphasizes the need for more effort to address the insufficient and unbalanced development, along with the growing eco-environmental challenges, especially the trade-offs among dimensions.
基金This work was financially supported by the National Key Research and Development Program of China(Grant No.2017YFD0701500)and the Hebei Province Key Research and Development Program(Grant No.19227214D).
文摘Under the extremely cold climatic condition,crops have to survive severe heat stress conditions,even if they are being kept in greenhouses.In the winter and spring of North China,the air and soil temperature is low inside the greenhouse,and when using a traditional heating system,the energy consumption is high.This paper reports on a study of different design solutions for a root zone heating system based on a kind of low temperature radiation material.Root zone heating systems offer increasing crop quality and productivity.A novel type of heat preservation and root zone heating system was applied in greenhouse seedling.And through multiple experiments,the effect of the root zone heating system on the ambient environment and seedbed surface was studied,and the heat preservation effect and heating uniformity were discussed.Results show that single-layer film covering on the root zone heating system can make the average temperature at night increase 1°C.And the average seedbed surface and substrate temperature can increase 11.3°C and 5.2°C,respectively.In conclusion,the root zone heating system can effectively improve the environmental temperature of seedling and the uniformity of heating is high,which provides a strong guarantee for high-quality seedling cultivation.
基金support provided by Hebei Province Key Research and Development Program(Grant No.21327210D)Independent Research and Development Plan of Academy of Agricultural Planning and Engineering,Ministry of Agriculture and Rural Affairs(Grant No.SP202101,Grant No.QD202107).
文摘Heating greenhouse is indispensable for plant development particularly in winter when the air temperature is lower.In that sense,root zone heating is more energy-saving than traditional air heating.The current work was devoted to the study of the effect of two root zone heating systems based on carbon crystal electrothermal film and low temperature hot water pipe on the microclimate and tomato yield in solar greenhouse.And their performance was tested in the coldest period of winter in Yongqing County of Hebei Province.The results showed that the use of root zone heating system can improve the average substrate temperature by 6.8℃.This microclimate improvement had a positive impact on tomato production.The output per square meter has increased by 19%compared to the unheated.It was also noted that the presence of root zone heating leads to a decrease in the development of disease in heated areas.Based on these results,the root zone heating system can be an effective method of improving the environmental temperature of crop plant,which is of great significance for increasing crop yield.
基金the Promotion China Ph.D.Pro-gram of BMW Brilliance Automotive Ltd.and Beijing Municipal Ed-ucation Commission and Beijing Municipal Natural Science Foun-dation(No.KZ200010009041)for financial support and KOBELCO and TAGAL for providing commercial automotive sheets.
文摘6016-T4 aluminum alloy and DP490 steel were systematically tested under 24 proportional loading paths,including uniaxial tensile tests with a 15°increment,uniaxial compressive and simple shear tests with a 45°increment,and biaxial tensile tests using cruciform specimens.Cruciform specimens in the rolling/transverse and 45°/135°sampling directions were tested with seven and four different stress ra-tios,respectively.The normal and diagonal planes plastic work contours and the yield stresses under uniaxial tension and compression were measured to investigate the anisotropic yield.Meanwhile,the normal and diagonal planes directions of plastic strain rate and the rα-values under uniaxial tension and compression were characterized to confirm the plastic flow.Several existing asymmetric yield crite-ria under the associated and non-associated flow rules were comprehensively evaluated to describe the asymmetric plastic anisotropy of 6016-T4 aluminum alloy and DP490 steel.The results suggest that in the investigated yield criteria,the non-associated models can predict the tension and compression asym-metry of materials more accurately than the associated models,and the function of stress triaxiality can more effectively describe the asymmetric yield behavior than the first stress invariant.In addition,the pure shear stress states are helpful in assessing the validity and applicability of advanced asymmetric yield stress functions,and the inspection of diagonal plane plastic work contours containing more pure shear stress states should prioritized over that of normal plane plastic work contours.The evaluation of plastic potential functions should not only consider the prediction accuracy of the normal plane di-rections of plastic strain rate,but also further check the diagonal plane directions of plastic strain rate.Expressing mechanical properties as a function of equivalent plastic strain to calibrate parameters of the yield criterion allows the continuous capture of anisotropic evolution of the asymmetric yield surface and the changes in the asymmetric plastic potential surface.
基金supported by the Major Science and Technology Project of Yunnan Province (202202AE090034)the Project of Beijing’s Top-Precision-Advanced Disciplinesthe Key Consulting Project of the Chinese Academy of Engineering
文摘Pollution of high-altitude lake basins by agriculture and rural activities,and the control of this pollution,have received increasing attention from academic research and government policy in China.Series of restrictions and regulations have been implemented to protect the surface,water quality.These restrictions and regulations have greatly impacted and transformed the agricultural systems and rural livelihoods surrounding these lake basins.Using Erhai Lake basin in Yunnan Province as a case study,three main challenges were identified for concurrently decreasing pollution in the lake and increasing farmer income.It is contended that scientifically-sound environmental protection policies and agricultural green development practices are key to reversing the current situation.This will help to protect the lake from pollution while smallholder farmers will be able to produce healthy food in an environmentally sustainable manner,and with a fair remuneration for all the services farmers providetothe society.
基金support of the BK21 Four program(SNU Materials Education/Research Division for Creative Global Leaders)support from the Science and Technology Commission of Shanghai Municipality(grant number:21170711200)+2 种基金MGL appreciates the grant from NRF(No.2022R1A2C2009315)supported by the KEIT(1415185590,20022438)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea).
文摘Lightweight sheet metals are highly desirable for automotive applications due to their exceptional strength-to-density ratio.An accurate description of the pronounced plastic anisotropy exhibited by these materials in finite element analysis requires advanced plasticity models.In recent years,significant efforts have been devoted to developing plasticity models and numeri-cal analysis methods based on the non-associated flow rule(non-AFR).In this work,a newly proposed coupled quadratic and non-quadratic model under non-AFR is utilized to comprehensively investigate the non-associated and non-quadratic characteristics during the yielding of three lightweight sheet metals,i.e.,dual-phase steel DP980,TRIP-assisted steel QP980,and aluminum alloy AA5754-O.These materials are subjected to various proportional loading paths,including uniaxial tensile tests with a 15°increment,uniaxial compressive tests with a 45°increment,in-plane torsion tests,and biaxial tensile tests using laser-deposited arm-strengthened cruciform specimens.Results show that the non-AFR approach provides an effective means for accurately modeling the yield behavior,including yield stresses and the direction of plastic strain rates,simultaneously,utilizing two separate functions and a simple calibration procedure.The introduction of the non-quadratic plastic potential reduces the average errors in angle when predicting plastic strain directions by the quadratic plastic potential function.Specifically,for DP980,the average error is reduced from 3.1°to 0.9°,for QP980 it is reduced from 6.1°to 3.9°,and for AA5754-O it is reduced from 7.0°to 0.2°.This highlights the importance of considering the non-quadratic characteristic in plasticity modeling,especially for aluminum alloys such as AA5754-O.
基金supported by the Project of Beijing’s Top-Precision-Advanced Disciplinesthe CSC-AGD Ph D Program from China Scholarship Council(CSC)the Key Consulting Project of the Chinese Academy of Engineering。
文摘Realizing sustainable development has become a global priority.This holds,in particular,for agriculture.Recently,the United Nations launched the Sustainable Development Goals(SDGs),and the Nineteenth National People’s Congress has delivered a national strategy for sustainable development in China—realizing green development.The overall objective of Agriculture Green Development(AGD)is to coordinate"green"with"development"to realize the transformation of current agriculture with high resource consumption and high environmental costs into a green agriculture and countryside with high productivity,high resource use efficiency and low environmental impact.This is a formidable task,requiring joint efforts of government,farmers,industry,educators and researchers.The innovative concept for AGD will focus on reconstructing the whole crop-animal production and food production-consumption system,with the emphasis on high thresholds for environmental standards and food quality as well as enhanced human well-being.This paper addresses the significance,challenges,framework,pathways and potential solutions for realizing AGD in China,and highlights the potential changes that will lead to a more sustainable agriculture in the future.Proposals include interdisciplinary innovations,whole food chain improvement and regional solutions.The implementation of AGD in China will provide important implications for the countries in developmental transition,and contribute to global sustainable development.
基金supported by grants from the National Natural Science Foundation of China (81830051, 31525008, 31670911, 31800744 and 31961133011)Shanghai Academic Research Leader (16XD1403800)+2 种基金Shenzhen Municipal Government of China (JCYJ20170817145428361)Shanghai Jiao Tong University (SJTU)The Chinese University of Hong Kong (CUHK) Joint Research Collaboration Fundthe Fundamental Research Funds for Central Universities and the Gusu innovation and entrepreneurship leader talent program。
基金support from the Academy for Agricultural Green Development,the UK-China Virtual Joint Centres on Nitrogen,N-Circle and CINAgfunded by the Newton Fund via UK BBSRC/NERC(BB/N013484/1 and BB/N013468/1,respectively)+1 种基金the Chinese Ministry of Science and Technology,and the Sustainable Agriculture Innovation Network(SAIN)financial support from the National Natural Science Foundation of China(31772393)for supporting Yong Hou。
文摘As the demand for livestock products continues to increase in China,so too does the challenge of managing increasing quantities of manure.Urgent action is needed to control point source(housing,storage and processing)and diffuse(field application)pollution and improve the utilization of manure nutrients and organic matter.Here,we review strategies to improve management at each stage of the manure management chain and at different scales.Many strategies require infrastructure investment,e.g.,for containment of all manure fractions.Engineering solutions are needed to develop advanced composting systems with lower environmental footprints and design more efficient nutrient stripping technologies.At the field-scale,there is an urgent need to develop a manure nutrient recommendation system that accounts for the range of manure types,cropping systems,soils and climates throughout China.At the regional scale,coordinated planning is necessary to promote recoupling of livestock and cropping systems,and reduce nutrient accumulation in regions with little available landbank,while minimizing the risk of pollution swapping from one region to another.A range of stakeholders are needed to support the step change and innovation required to improve manure management,reduce reliance on inorganic fertilizers,and generate new business opportunities.