In the new phase of sustainable development,agriculture is seeking sustainable management of the water-land-energy-economy-environment-food nexus.At present,there are few studies on optimizing crop planting structure ...In the new phase of sustainable development,agriculture is seeking sustainable management of the water-land-energy-economy-environment-food nexus.At present,there are few studies on optimizing crop planting structure and analyzing its spatial layout with consideration of natural and socio-economic factors.Herein,we proposed a framework for addressing this issue.In this framework,the NSGA-II algorithm was used to construct the multi-objective optimization model of crop planting structures with consideration of water and energy consumption,greenhouse gas(GHG)emissions,economic benefits,as well as food,land,and water security constraints,while the model for planting spatial layout optimization was established with consideration of crop suitability using the MaxEnt model and the improved Hungarian algorithm.This framework was further applied in the Black Soil Region of Northeast China(BSRNC)for analyzing optimized crop planting structures and spatial layouts of three main crops(rice,maize,and soybean)under various scenarios.This study showed that the sown area of rice in the BSRNC decreased by up to 40.73%and 35.30%in the environmental priority scenario and economic-environmental balance scenario,respectively,whereas that of soybean increased by up to 112.44%and 63.31%,respectively.In the economic priority scenario,the sown area of rice increased by up to 93.98%.Expanding the sown area of soybean was effective in reducing GHG emissions.On the contrary,rice production led to greater environmental costs though it provided higher economic returns.Among the three crops,maize exhibited an advantage in balancing environmental and economic benefits.Hegang-Jixi area in the northeast of the BSRNC was identified as the key area with the most intense crop planting transfer among different scenarios.Overall,this framework provides a new methodology for optimizing crop planting structures and spatial layouts with con-sideration of the nexus of various factors.Moreover,the case study demonstrates the applicability and expansion potential of the framework in the fields of sustainable agricultural development and food security assurance.展开更多
Ultrahigh pressure generation at high temperatures is technologically challenging for large sample volumes.In this study,we successfully generated pressures of 37.3-40.4 GPa at 1900-2100 K in a Walker-type large-volum...Ultrahigh pressure generation at high temperatures is technologically challenging for large sample volumes.In this study,we successfully generated pressures of 37.3-40.4 GPa at 1900-2100 K in a Walker-type large-volume press(LVP).Expansion of the pressure range at high temperatures was achieved by adapting newly designed ZK01F tungsten carbide(WC)anvils with tapered surfaces and using cell assemblies with an^(-1) mm^(3) sample volume and hard materials,as well as by applying certain adjustments to the apparatus.The pressure efficiencies of the different types of WC anvils and cell assemblies were also studied.Using the above-mentioned techniques,we successfully synthesized and characterized bulk samples of nearly pure sp3-hybridized ultrahard amorphous carbon,core-shell nanocrystals with high Néel temperatures,as well as large-sized single crystals of lower-mantle minerals.The developed LVP techniques presented here could enable the exploration of the chemical and physical properties of novel materials and Earth’s interior.展开更多
Continuously improving the mechanical properties of ultra-high-temperature ceramics(UHTCs)is a key requirement for their future applications.However,the mechanical properties of conventional UHTCs,HfB_(2) and ZrB_(2),...Continuously improving the mechanical properties of ultra-high-temperature ceramics(UHTCs)is a key requirement for their future applications.However,the mechanical properties of conventional UHTCs,HfB_(2) and ZrB_(2),remain unsatisfactory among transition metal light-element(TMLE)compounds.TiB_(2) has superior mechanical properties compared to both HfB_(2) and ZrB_(2),but suffers from inherent brittleness and limited oxidation resistance.In this work,low-content solidsolution strengthening was used to fabricate dense samples of Tix(Hf/Zr)_(1-x)B_(2)(THZ)under high pressure and high temperature(HPHT).Compared to pure TiB_(2),Ti_(0.94)(Hf/Zr)0.06B_(2) exhibits a significant 38.8%increase in oxidation resistance temperature(950℃),while Ti_(0.91)(Hf/Zr)_(0.09)B_(2) shows a notable 28%enhancement in fracture toughness(5.8 MPa·m^(1/2)).The synergistic effect of a dual-atom solid-solution results in local internal stress and anomalous lattice contraction.This lattice contraction helps resist oxygen invasion,thereby elevating the oxidation resistance threshold.Additionally,the internal stress induces crack deflection within individual grains,enhancing toughness through energy dissipation.This work provides a new strategy for fabricating robust UHTCs within TMLE systems,demonstrating significant potential for future high-temperature applications.展开更多
The excessive buildup of neurotoxicα-synuclein plays a pivotal role in the pathogenesis of Parkinson's disease,highlighting the urgent need for innovative therapeutic strategies to promoteα-synuclein clearance,p...The excessive buildup of neurotoxicα-synuclein plays a pivotal role in the pathogenesis of Parkinson's disease,highlighting the urgent need for innovative therapeutic strategies to promoteα-synuclein clearance,particularly given the current lack of disease-modifying treatments.The glymphatic system,a recently identified perivascular fluid transport network,is crucial for clearing neurotoxic proteins.This review aims to synthesize current knowledge on the role of the glymphatic system inα-synuclein clearance and its implications for the pathology of Parkinson's disease while emphasizing potential therapeutic strategies and areas for future research.The review begins with an overview of the glymphatic system and details its anatomical structure and physiological functions that facilitate cerebrospinal fluid circulation and waste clearance.It summarizes emerging evidence from neuroimaging and experimental studies that highlight the close correlation between the glymphatic system and clinical symptom severity in patients with Parkinson's disease,as well as the effect of glymphatic dysfunction onα-synuclein accumulation in Parkinson's disease models.Subsequently,the review summarizes the mechanisms of glymphatic system impairment in Parkinson's disease,including sleep disturbances,aquaporin-4 impairment,and mitochondrial dysfunction,all of which diminish glymphatic system efficiency.This creates a vicious cycle that exacerbatesα-synuclein accumulation and worsens Parkinson's disease.The therapeutic perspectives section outlines strategies for enhancing glymphatic activity,such as improving sleep quality and pharmacologically targeting aquaporin-4 or its subcellular localization.Promising interventions include deep brain stimulation,melatonin supplementation,γ-aminobutyric acid modulation,and non-invasive methods(such as exercise and bright-light therapy),multisensoryγstimulation,and ultrasound therapy.Moreover,identifying neuroimaging biomarkers to assess glymphatic flow as an indicator ofα-synuclein burden could refine Parkinson's disease diagnosis and track disease progression.In conclusion,the review highlights the critical role of the glymphatic system inα-synuclein clearance and its potential as a therapeutic target in Parkinson's disease.It advocates for further research to elucidate the specific mechanisms by which the glymphatic system clears misfoldedα-synuclein and the development of imaging biomarkers to monitor glymphatic activity in patients with Parkinson's disease.Findings from this review suggest that enhancing glymphatic clearance is a promising strategy for reducingα-synuclein deposits and mitigating the progression of Parkinson's disease.展开更多
Noise is one of the key issues in the operation of high-speed railways, with sound source localisation and its transfer path as the two major aspects. This study investigates both the exterior and interior sound sourc...Noise is one of the key issues in the operation of high-speed railways, with sound source localisation and its transfer path as the two major aspects. This study investigates both the exterior and interior sound source distribution of a high-speed train and presents a method for performing the contribution analysis of airborne sound with regard to the interior noise. First, both exterior and interior sound source locations of the high-speed train are identified through in-situ measurements. Second, the sound source contribution for di erent regions of the train and the relationships between the exterior and interior noises are analysed. Third, a method for conducting the contribution analysis of airborne sound with regard to the interior noise of the high-speed train is described. Lastly, a case study on the sidewall area is carried out, and the contribution of airborne sound to the interior noise of this area is obtained. The results show that, when the high-speed train runs at 310 km/h, dominant exterior sound sources are located in the bogie and pantograph regions, while main interior sound sources are located at the sidewall and roof. The interior noise, the bogie area noise and the sound source at the middle of the coach exhibit very similar rates of increase with increasing train speed. For the selected sidewall area, structure-borne sound dominates in most of the 1/3 octave bands.展开更多
Background:The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis.However,the low incidence and unpredictability of symp...Background:The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis.However,the low incidence and unpredictability of symptoms are caused by numerous complex variant types of the circle.Additionally,the lack of an evaluation system for the cer-ebral ischemia/reperfusion(I/R)model of gerbils has shackled the application of this model.Methods:We created a symptom-oriented principle and detailed neurobehavioral scoring criteria.At different time points of reperfusion,we analyzed the alteration in locomotion by rotarod test and grip force score,infarct volume by triphenyltetrazo-lium chloride(TTC)staining,neuron loss using Nissl staining,and histological charac-teristics using hematoxylin-eosin(H&E)straining.Results:With a successful model rate of 56%,32 of the 57 gerbils operated by our method harbored typical features of cerebral I/R injury,and the mortality rate in the male gerbils was significantly higher than that in the female gerbils.The suc-cessfully prepared I/R gerbils demonstrated a significant reduction in motility and grip strength at 1 day after reperfusion;formed obvious infarction;exhibited typi-cal pathological features,such as tissue edema,neuronal atrophy and death,and vacuolated structures;and were partially recovered with the extension of reperfu-sion time.Conclusion:This study developed a new method for the unilateral common carotid artery ligation I/R model of gerbil and established a standardized evaluation system for this model,which could provide a new cerebral I/R model of gerbils with more practical applications.展开更多
2,5-Dicyanofuran(DCF)is an important biomass-derived platform compound primarily used to prepare bio-based adiponitrile,which is the key precursor for the synthesis of nylon 66 and 1,6-hexanediisocyanate(HDI).In this ...2,5-Dicyanofuran(DCF)is an important biomass-derived platform compound primarily used to prepare bio-based adiponitrile,which is the key precursor for the synthesis of nylon 66 and 1,6-hexanediisocyanate(HDI).In this study,one-pot,green and safe synthesis of DCF from 2,5-diformylfuran(DFF)and hydroxylamine ionic liquid salts was proposed.Eco-friendly hydroxylamine ionic liquid salts were used as the nitrogen source.Ionic liquid exhibited three-fold function of cosolvent,catalysis and phase separation.The conversion of DFF and yield of DCF reached 100%under the following optimum reaction conditions:temperature of 120℃ for 70 min,volume ratio of paraxylene:[HSO_(3)-b-Py]HSO4 of 2:1,and molar ratio of DFF:(NH_(2)OH)_(2)[HSO_(3)-b-Py]HSO4 of 1:1.5.The reaction mechanism for the synthesis of DCF was proposed,and the kinetic model was established.The reaction order with respect to DFF and intermediate product 2,5-diformylfuran dioxime(DFFD)was 1.06 and 0.16,and the reaction activation energy was 64.07 kJ·mol^(-1) and 59.37 kJ·mol^(-1) respectively.After the reaction,the ionic liquid was easy to separate,recover and recycle.展开更多
Using microbial fermentation to increase the content of free amino acids and short peptides in the organic fertilizer for castor bean meal can effectively promote plant growth and improve fruit quality.Using free amin...Using microbial fermentation to increase the content of free amino acids and short peptides in the organic fertilizer for castor bean meal can effectively promote plant growth and improve fruit quality.Using free amino acid and short peptide content as an indicator,through single factor and response surface optimization experiments,the process parameters(moisture content,fermentation time and inoculum quantity)of castor meal solid-state fermentation were optimized.The best process parameters for the solid-state fermentation were:the moisture content 62%,the fermentation time 20 d,and the inoculum quantity 0.23%.The moisture content had the greatest impact on the conversion rate of free amino acids and short peptides,and the protein conversion rate reached 65.6%.The scale-up experiment under the optimal conditions showed that the solid-state fermentation using the inoculum had a significant beneficial effect compared with other fermentation methods.The fermentation of castor cake fertilizer provides a theoretical and practical basis for production feasibility,and has important guiding significance for the effective utilization of castor bean meal.展开更多
As a kind of white light emitting diode(w-LED)with many advantages,rare-earth-free vanadate phosphor has attracted more and more attention.The oxygen vacancies and other surface defects in vanadate oxide have obvious ...As a kind of white light emitting diode(w-LED)with many advantages,rare-earth-free vanadate phosphor has attracted more and more attention.The oxygen vacancies and other surface defects in vanadate oxide have obvious effects on its structure and properties.In order to reveal the specific effects,we heat-treat the original LiCa_(3)Mg(VO_(4))_(3)(LCMV)in an oxygen flow with different time to decrease oxygen vacancies,and find that the lattice distortion of[VO_(4)]tetrahedron caused by oxygen vacancy is effectively reduced.Meanwhile,the crystallinity of the treated samples increases,the surface defects decreases,and the fluorescence intensity increases.The variation of photoluminescence quantum yield(PLQY)with oxygen treatment time is as follows:the enhancement effect firstly reaches the strongest(69.34%)within one hour,then begins to decline after two hours,and finally reaches the platform after three hours and remains basically unchanged.The reason for the enhancement of PLQY is the decrease of oxygen vacancy after one-hour treatment,and the reason for the decrease of PLQY after a further increased treatment time is that the absorption of oxygen and water in air caused by excessive surface defects introduced by oxygen treatment.展开更多
This study aims to investigate the effect of the impact mechanism of climate change on the livestock production at small watershed level and county level with the Multi-level Model(MLM)in Qinghai Province.The result i...This study aims to investigate the effect of the impact mechanism of climate change on the livestock production at small watershed level and county level with the Multi-level Model(MLM)in Qinghai Province.The result indicated that the gross livestock output value was greatly influenced by the climatic factors of the small watershed level.Higher temperature promoted also by the increase of precipitation,relative humidity and sunshine duration was found to be beneficial to the development of livestock production,except in some areas where temperature rise restrained the development of local livestock production to some degree when exceeding a certain level;besides,the impact of the socioeconomic factors on the livestock output value is obvious at the county level.The gross economic output measured with GDP has some inhibitory effects on the reinvestment of livestock production,while population growth promotes development of livestock production to some degree.The results not only provide scientific basis for the management of livestock production in Qinghai Province,but also provide reference for formulating the policies and adaptation measures targeted at climate change to promote the sustainable development of livestock production in other regions.展开更多
Background:Uneven economic development has led to substantial health inequalities between Chinese provinces.The extent of,and factors underlying,between-province health inequalities have received little attention.Meth...Background:Uneven economic development has led to substantial health inequalities between Chinese provinces.The extent of,and factors underlying,between-province health inequalities have received little attention.Methods:Data from 15,278 respondents in Wave 2(2013)of the China Health and Retirement Longitudinal Study(CHARLS)were used to investigate inequalities among people aged≥50 years in five health outcomes between 27 Chinese province-level administrative units.After characterizing the betweenprovince differences and the relevance of province effects,proportional change in variance between unadjusted and adjusted models was calculated to determine the percentage of between-province variance in health outcomes explained by province-level variables including measures of economic development and healthcare availability.Results:Although province effects explained<10%of overall variance in health outcomes,they underpinned large between-province inequalities among people aged≥50 years.Gross Regional Product per capita was more important than doctor density in explaining between-province variance in health outcomes,particularly depression symptoms and instrumental activities of daily living impairment.Conclusion:Policy efforts,including more equal distribution of healthcare personnel,may be warranted to reduce between-province health inequalities.展开更多
Based on the experimental data of Mn_(1)Co_(0.5)Cr_(0.5)O_(x)catalysts and the component transport model in computational fluid dynamics(CFD),a kinetic model for the standard NH_(3)-SCR(NH_(3)selective catalytic reduc...Based on the experimental data of Mn_(1)Co_(0.5)Cr_(0.5)O_(x)catalysts and the component transport model in computational fluid dynamics(CFD),a kinetic model for the standard NH_(3)-SCR(NH_(3)selective catalytic reduction)process was effectively established.The objective of the model development was to predict the denitrification reaction rate of the catalyst,which incorporates various factors such as the Arrhenius parameters(pre-exponential factor and activation energy),inertial resistance,viscous resistance,and surface-to-volume ratio.To verify the practicability of the model,simulation results were compared with actual experimental data.The effects of NH_(3),NO,O_(2)concentrations,and gas hourly space velocity(GHSV)on NO conversion were simulated and analyzed.Subsequently,the NO conversion prediction model was trained and established using a combination of numerical simulation results,backpropagation neural network,and genetic algorithm(BP-GA).Furthermore,the significance of the impact that various factors had on the denitrification activity of the catalyst was determined.展开更多
In recent years,polymer-based triboelectric nanogenerators(TENGs)have been increasingly applied in the field of flexible wearable electronics.However,the lack of flame retardancy of existing TENGs greatly lim-its thei...In recent years,polymer-based triboelectric nanogenerators(TENGs)have been increasingly applied in the field of flexible wearable electronics.However,the lack of flame retardancy of existing TENGs greatly lim-its their applications in extreme circumstances.Herein,an ultra-thin and highly flexible aramid nanofiber(ANF)/MXene(Ti_(3)C_(2)T_(x))/Ni nanochain composite paper was prepared through vacuum-assisted filtration and freeze-drying technology.Owing to the synergistic effect between ANF and MXene,the composite paper not only possessed excellent mechanical properties,which were able to withstand over 10,000 times its own weight,but also exhibited outstanding flame-retardant and controllable Joule heating ca-pabilities.Moreover,the mechanical energy capture characteristics of the composite paper-based TENG were evaluated,resulting in the open-circuit voltage(55.6 V),short-circuit current(0.62μA),and trans-ferred charge quantity(25μC).It also could enable self-powering as a wearable electronic device with an instantaneous power of 15.6μW at the optimal external resistance of 10 MΩ.This work is intended to set TENG as safe energy harvesting devices for reducing fire hazards,and will provide a new strategy to broaden the application ranges of TENG.展开更多
Tin sulfide(SnS)is a promising non-toxic thermoelectric(TE)material to replace SnSe(Se is toxic),due to its similar structure and low thermal conductivity(k)comparable to SnSe.However,the poor electrical conductivity(...Tin sulfide(SnS)is a promising non-toxic thermoelectric(TE)material to replace SnSe(Se is toxic),due to its similar structure and low thermal conductivity(k)comparable to SnSe.However,the poor electrical conductivity(s)of SnS results in lower TE performance.In this work,high pressure was utilized to regulate the electronic structure,thereby mediating the conflict of electron and phonon transport to optimize the TE performance.In situ measurements of thermoelectric properties for SnS under high pressure and high temperature revealed that although the Seebeck coefficient(S)and k slightly decrease with increasing pressure,the s dramatically increases with increasing pressure,finally increasing the dimensionless figure of merit(ZT).The s increases from 2135 S·m^(-1)to 83549 S·m^(-1)as the pressure increases from 1 GPa to 5 GPa at 325 K,representing an increase of an order of magnitude.The high s of SnS leads to an increase in the PF to 1436μW·m^(-1)·K^(-2)at 5 GPa and 652 K.The maximum ZT value of 0.77 at 5 GPa and 652 K was obtained,which is 4 times the maximum ZT under ambient pressure and is comparable to that of doped SnS.The increase in s is due to the fact that pressure modulates the band structure of SnS by narrowing the band gap from 1.013 eV to 0.712 eV.This study presents a valuable guide for searching new high TE performance materials using high pressure.展开更多
As a kind of actuation mechanism for power-by-wire(PBW) actuation systems of more/all electrical aircraft, an electro-hydrostatic actuator(EHA) is a highly integrated local hydraulic actuation system. It is a volume c...As a kind of actuation mechanism for power-by-wire(PBW) actuation systems of more/all electrical aircraft, an electro-hydrostatic actuator(EHA) is a highly integrated local hydraulic actuation system. It is a volume control system consisting of a motor, a pump, an actuator, etc.,which has features of high efficiency and reliability. However, the poor dynamic characteristic is one of the main factors restricting its wide application in aircraft. In this paper, the reason for the poor dynamic characteristic of an EHA is revealed from the perspectives of the natural frequency characteristic and the power requirement, respectively. In other words, the insufficiency of the motor output power at a high frequency is the main factor causing the poor dynamic characteristic of the system, and methods which include increasing the maximum output torque of the motor, reducing the rotational inertia of the motor-pump group, and adopting a double-motorpump group configuration are proposed in this paper, by which the dynamic characteristic of the system can be improved. The feasibility of those methods are verified by simulations. Finally, the dynamic characteristic is tested on an EHA prototype, and results show that saturation of the output torque of the motor is the main factor restricting the dynamic characteristic of the EHA system.展开更多
Human wellness is the ultimate goal of our efforts in improving the human life.Special foods are undoubtedly important in achieving human wellness.However,overeating significantly leads to obesity and diabetes.These c...Human wellness is the ultimate goal of our efforts in improving the human life.Special foods are undoubtedly important in achieving human wellness.However,overeating significantly leads to obesity and diabetes.These chronic diseases will in turn affect the human wellness.Therefore,“dietary restriction and proper exercise”were introduced in the human daily life.Different foods cause various effects on the human health.The diversification of diet is a priority for nutritionists to keep our body healthy.To avoid diabetes mellitus,special foods for ketogenic diet,low-carbon diet,and low-calorie intake are also gradually attracting attention.In addition,the hypothesis that“hunger sensation comes from gut flora”brings new light to the research on the biological motivation for humans to eat food.This hypothesis has been gradually demonstrated using the flexible fasting technology by providing special foods,such as plant polysaccharides and dietary fibers.The response to food-needing signals from the gut flora to these foods demonstrates the importance of the gut flora in improving human wellness.The gut flora is probably an essential factor for translating the food-eating signals and converting the nutrition to our body.Therefore,“gut flora priority principle”is developed to guarantee human wellness.The 16S rRNA sequencing and mass spectrometric techniques can be used to identify the gut flora,which may guide us to a new era of human wellness based on gut flora wellness.展开更多
Under hypersonic flow conditions, the complicated gas-graphene interactions including surface catalysis and surface ablation would occur concurrently and intervene together with the thermodynamic response induced by s...Under hypersonic flow conditions, the complicated gas-graphene interactions including surface catalysis and surface ablation would occur concurrently and intervene together with the thermodynamic response induced by spacecraft reentry. In this work, the competing effects of surface heterogeneous catalytic recombination and ablation characteristics at elevated temperatures are investigated using the Reactive Molecular Dynamics(RMD) simulation method. A GasSurface Interaction(GSI) model is established to simulate the collisions of hyper-enthalpy atomic oxygen on graphene films in the temperature range of 500–2500 K. A critical temperature Tcaround900 K is identified to distinguish the graphene responses into two parts: at T < T_(c), the heterogeneous surface catalysis dominates, while the surface ablation plays a leading role at T > T_(c). Contradicting to the traditional Arrhenius expression that the recombination coefficient increases with the increase of surface temperature, the value is found to be relatively uniform at T < T_(c) but declines sharply as the surface temperature increases further due to the competing ablation effect. The occurrence of surface ablation decreases the amounts of active sites on the graphene surface for oxygen adsorption, leading to reduced recombination coefficient from both Langmuir-Hinshelwood(L-H) and Eley-Rideal(E-R) mechanisms. It suggests that the traditional Computational Fluid Dynamics(CFD) simulation method, which relies on the Arrhenius-type catalysis model, would result in large discrepancies in predicting aerodynamic heat for carbon-based materials during reentry into strong aerodynamic thermal environment.展开更多
基金funded by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.72221002)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA28060200)National Natural Science Foundation of Youth Project(Grant No.72303087).
文摘In the new phase of sustainable development,agriculture is seeking sustainable management of the water-land-energy-economy-environment-food nexus.At present,there are few studies on optimizing crop planting structure and analyzing its spatial layout with consideration of natural and socio-economic factors.Herein,we proposed a framework for addressing this issue.In this framework,the NSGA-II algorithm was used to construct the multi-objective optimization model of crop planting structures with consideration of water and energy consumption,greenhouse gas(GHG)emissions,economic benefits,as well as food,land,and water security constraints,while the model for planting spatial layout optimization was established with consideration of crop suitability using the MaxEnt model and the improved Hungarian algorithm.This framework was further applied in the Black Soil Region of Northeast China(BSRNC)for analyzing optimized crop planting structures and spatial layouts of three main crops(rice,maize,and soybean)under various scenarios.This study showed that the sown area of rice in the BSRNC decreased by up to 40.73%and 35.30%in the environmental priority scenario and economic-environmental balance scenario,respectively,whereas that of soybean increased by up to 112.44%and 63.31%,respectively.In the economic priority scenario,the sown area of rice increased by up to 93.98%.Expanding the sown area of soybean was effective in reducing GHG emissions.On the contrary,rice production led to greater environmental costs though it provided higher economic returns.Among the three crops,maize exhibited an advantage in balancing environmental and economic benefits.Hegang-Jixi area in the northeast of the BSRNC was identified as the key area with the most intense crop planting transfer among different scenarios.Overall,this framework provides a new methodology for optimizing crop planting structures and spatial layouts with con-sideration of the nexus of various factors.Moreover,the case study demonstrates the applicability and expansion potential of the framework in the fields of sustainable agricultural development and food security assurance.
基金supported by the National Key Research and Development Program of China(2022YFB3706600 and 2023YFA1406200)the National Natural Science Founda-tion of China(42272041,52302043,12304015,41902034,and 12011530063)+1 种基金the Jilin University High-level Innovation Team Foundation,China(2021TD-05)the National Major Science Facility Synergetic Extreme Condition User Facility Achievement Transformation Platform Construction(2021FGWCXNLJSKJ01).
文摘Ultrahigh pressure generation at high temperatures is technologically challenging for large sample volumes.In this study,we successfully generated pressures of 37.3-40.4 GPa at 1900-2100 K in a Walker-type large-volume press(LVP).Expansion of the pressure range at high temperatures was achieved by adapting newly designed ZK01F tungsten carbide(WC)anvils with tapered surfaces and using cell assemblies with an^(-1) mm^(3) sample volume and hard materials,as well as by applying certain adjustments to the apparatus.The pressure efficiencies of the different types of WC anvils and cell assemblies were also studied.Using the above-mentioned techniques,we successfully synthesized and characterized bulk samples of nearly pure sp3-hybridized ultrahard amorphous carbon,core-shell nanocrystals with high Néel temperatures,as well as large-sized single crystals of lower-mantle minerals.The developed LVP techniques presented here could enable the exploration of the chemical and physical properties of novel materials and Earth’s interior.
基金support from the Program for the Development of Science and Technology of Jilin Province(Grant No.SKL202402004)the Jilin Province Major Science and Technology Program(Grant No.20240211002GX)the Open Research Fund of the Key Laboratory of Functional Materials Physics and Chem-istry of the Ministry of Education(Jilin Normal University,Grant No.202405).
文摘Continuously improving the mechanical properties of ultra-high-temperature ceramics(UHTCs)is a key requirement for their future applications.However,the mechanical properties of conventional UHTCs,HfB_(2) and ZrB_(2),remain unsatisfactory among transition metal light-element(TMLE)compounds.TiB_(2) has superior mechanical properties compared to both HfB_(2) and ZrB_(2),but suffers from inherent brittleness and limited oxidation resistance.In this work,low-content solidsolution strengthening was used to fabricate dense samples of Tix(Hf/Zr)_(1-x)B_(2)(THZ)under high pressure and high temperature(HPHT).Compared to pure TiB_(2),Ti_(0.94)(Hf/Zr)0.06B_(2) exhibits a significant 38.8%increase in oxidation resistance temperature(950℃),while Ti_(0.91)(Hf/Zr)_(0.09)B_(2) shows a notable 28%enhancement in fracture toughness(5.8 MPa·m^(1/2)).The synergistic effect of a dual-atom solid-solution results in local internal stress and anomalous lattice contraction.This lattice contraction helps resist oxygen invasion,thereby elevating the oxidation resistance threshold.Additionally,the internal stress induces crack deflection within individual grains,enhancing toughness through energy dissipation.This work provides a new strategy for fabricating robust UHTCs within TMLE systems,demonstrating significant potential for future high-temperature applications.
基金supported by the National Natural Science Foundation of China,No.81971031(to ZL)the National Key Research and Development Program of China,No.2022YFE0210100(to JFC)+7 种基金the National Natural Science Foundation of China(Original Exploration Project),No.82151308(to JFC)the National Natural Science Foundation of China(Research Fund for International Senior Scientists),No.82150710558(to JFC)Science&Technology Initiative STI2030-Major Projects,No.2021ZD0203400(to JFC)Key Research and Development Program of Zhejiang Province,No.2023C03079(to JFC)Scientific Research Starting Foundation of Oujiang Laboratory(Zhejiang Laboratory for Regenerative Medicine,Vision and Brain Health),No.OJQDSP2022007(to JFC)Project of State Key Laboratory of Ophthalmology,Optometry and Visual Science,Wenzhou Medical University,No.J01-20190101(to JFC)Scientific Research Starting Foundation of Wenzhou Medical University,No.QTJ12003(to JFC)Department of Science and Technology of Zhejiang Province,No.2023ZY1011(to JFC)。
文摘The excessive buildup of neurotoxicα-synuclein plays a pivotal role in the pathogenesis of Parkinson's disease,highlighting the urgent need for innovative therapeutic strategies to promoteα-synuclein clearance,particularly given the current lack of disease-modifying treatments.The glymphatic system,a recently identified perivascular fluid transport network,is crucial for clearing neurotoxic proteins.This review aims to synthesize current knowledge on the role of the glymphatic system inα-synuclein clearance and its implications for the pathology of Parkinson's disease while emphasizing potential therapeutic strategies and areas for future research.The review begins with an overview of the glymphatic system and details its anatomical structure and physiological functions that facilitate cerebrospinal fluid circulation and waste clearance.It summarizes emerging evidence from neuroimaging and experimental studies that highlight the close correlation between the glymphatic system and clinical symptom severity in patients with Parkinson's disease,as well as the effect of glymphatic dysfunction onα-synuclein accumulation in Parkinson's disease models.Subsequently,the review summarizes the mechanisms of glymphatic system impairment in Parkinson's disease,including sleep disturbances,aquaporin-4 impairment,and mitochondrial dysfunction,all of which diminish glymphatic system efficiency.This creates a vicious cycle that exacerbatesα-synuclein accumulation and worsens Parkinson's disease.The therapeutic perspectives section outlines strategies for enhancing glymphatic activity,such as improving sleep quality and pharmacologically targeting aquaporin-4 or its subcellular localization.Promising interventions include deep brain stimulation,melatonin supplementation,γ-aminobutyric acid modulation,and non-invasive methods(such as exercise and bright-light therapy),multisensoryγstimulation,and ultrasound therapy.Moreover,identifying neuroimaging biomarkers to assess glymphatic flow as an indicator ofα-synuclein burden could refine Parkinson's disease diagnosis and track disease progression.In conclusion,the review highlights the critical role of the glymphatic system inα-synuclein clearance and its potential as a therapeutic target in Parkinson's disease.It advocates for further research to elucidate the specific mechanisms by which the glymphatic system clears misfoldedα-synuclein and the development of imaging biomarkers to monitor glymphatic activity in patients with Parkinson's disease.Findings from this review suggest that enhancing glymphatic clearance is a promising strategy for reducingα-synuclein deposits and mitigating the progression of Parkinson's disease.
基金Supported by National Key R&D Program of China(Grant No.2016YFE0205200)National Natural Science Foundation of China(Grant No.U1834201)
文摘Noise is one of the key issues in the operation of high-speed railways, with sound source localisation and its transfer path as the two major aspects. This study investigates both the exterior and interior sound source distribution of a high-speed train and presents a method for performing the contribution analysis of airborne sound with regard to the interior noise. First, both exterior and interior sound source locations of the high-speed train are identified through in-situ measurements. Second, the sound source contribution for di erent regions of the train and the relationships between the exterior and interior noises are analysed. Third, a method for conducting the contribution analysis of airborne sound with regard to the interior noise of the high-speed train is described. Lastly, a case study on the sidewall area is carried out, and the contribution of airborne sound to the interior noise of this area is obtained. The results show that, when the high-speed train runs at 310 km/h, dominant exterior sound sources are located in the bogie and pantograph regions, while main interior sound sources are located at the sidewall and roof. The interior noise, the bogie area noise and the sound source at the middle of the coach exhibit very similar rates of increase with increasing train speed. For the selected sidewall area, structure-borne sound dominates in most of the 1/3 octave bands.
基金National Key Research and Development Program of China,Grant/Award Number:2021YFF0702402National Natural Science Foundation of China,Grant/Award Number:32070531。
文摘Background:The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis.However,the low incidence and unpredictability of symptoms are caused by numerous complex variant types of the circle.Additionally,the lack of an evaluation system for the cer-ebral ischemia/reperfusion(I/R)model of gerbils has shackled the application of this model.Methods:We created a symptom-oriented principle and detailed neurobehavioral scoring criteria.At different time points of reperfusion,we analyzed the alteration in locomotion by rotarod test and grip force score,infarct volume by triphenyltetrazo-lium chloride(TTC)staining,neuron loss using Nissl staining,and histological charac-teristics using hematoxylin-eosin(H&E)straining.Results:With a successful model rate of 56%,32 of the 57 gerbils operated by our method harbored typical features of cerebral I/R injury,and the mortality rate in the male gerbils was significantly higher than that in the female gerbils.The suc-cessfully prepared I/R gerbils demonstrated a significant reduction in motility and grip strength at 1 day after reperfusion;formed obvious infarction;exhibited typi-cal pathological features,such as tissue edema,neuronal atrophy and death,and vacuolated structures;and were partially recovered with the extension of reperfu-sion time.Conclusion:This study developed a new method for the unilateral common carotid artery ligation I/R model of gerbil and established a standardized evaluation system for this model,which could provide a new cerebral I/R model of gerbils with more practical applications.
基金support from the National Natural Science Foundation of China(Nos.U20A20152,21236001 and 21878069).
文摘2,5-Dicyanofuran(DCF)is an important biomass-derived platform compound primarily used to prepare bio-based adiponitrile,which is the key precursor for the synthesis of nylon 66 and 1,6-hexanediisocyanate(HDI).In this study,one-pot,green and safe synthesis of DCF from 2,5-diformylfuran(DFF)and hydroxylamine ionic liquid salts was proposed.Eco-friendly hydroxylamine ionic liquid salts were used as the nitrogen source.Ionic liquid exhibited three-fold function of cosolvent,catalysis and phase separation.The conversion of DFF and yield of DCF reached 100%under the following optimum reaction conditions:temperature of 120℃ for 70 min,volume ratio of paraxylene:[HSO_(3)-b-Py]HSO4 of 2:1,and molar ratio of DFF:(NH_(2)OH)_(2)[HSO_(3)-b-Py]HSO4 of 1:1.5.The reaction mechanism for the synthesis of DCF was proposed,and the kinetic model was established.The reaction order with respect to DFF and intermediate product 2,5-diformylfuran dioxime(DFFD)was 1.06 and 0.16,and the reaction activation energy was 64.07 kJ·mol^(-1) and 59.37 kJ·mol^(-1) respectively.After the reaction,the ionic liquid was easy to separate,recover and recycle.
基金Special Fund for International Cooperative Research of Qilu University of Technology(QLUTGJHZ2018010)。
文摘Using microbial fermentation to increase the content of free amino acids and short peptides in the organic fertilizer for castor bean meal can effectively promote plant growth and improve fruit quality.Using free amino acid and short peptide content as an indicator,through single factor and response surface optimization experiments,the process parameters(moisture content,fermentation time and inoculum quantity)of castor meal solid-state fermentation were optimized.The best process parameters for the solid-state fermentation were:the moisture content 62%,the fermentation time 20 d,and the inoculum quantity 0.23%.The moisture content had the greatest impact on the conversion rate of free amino acids and short peptides,and the protein conversion rate reached 65.6%.The scale-up experiment under the optimal conditions showed that the solid-state fermentation using the inoculum had a significant beneficial effect compared with other fermentation methods.The fermentation of castor cake fertilizer provides a theoretical and practical basis for production feasibility,and has important guiding significance for the effective utilization of castor bean meal.
基金This work was sponsored by the National Natural Science Foundation of China(21972110,51702253)the National Key R&D Program of China(2018YFF02123001)the State Key Laboratory of Electrical Insulation and Power Equipment,China(EIPE19123)。
文摘As a kind of white light emitting diode(w-LED)with many advantages,rare-earth-free vanadate phosphor has attracted more and more attention.The oxygen vacancies and other surface defects in vanadate oxide have obvious effects on its structure and properties.In order to reveal the specific effects,we heat-treat the original LiCa_(3)Mg(VO_(4))_(3)(LCMV)in an oxygen flow with different time to decrease oxygen vacancies,and find that the lattice distortion of[VO_(4)]tetrahedron caused by oxygen vacancy is effectively reduced.Meanwhile,the crystallinity of the treated samples increases,the surface defects decreases,and the fluorescence intensity increases.The variation of photoluminescence quantum yield(PLQY)with oxygen treatment time is as follows:the enhancement effect firstly reaches the strongest(69.34%)within one hour,then begins to decline after two hours,and finally reaches the platform after three hours and remains basically unchanged.The reason for the enhancement of PLQY is the decrease of oxygen vacancy after one-hour treatment,and the reason for the decrease of PLQY after a further increased treatment time is that the absorption of oxygen and water in air caused by excessive surface defects introduced by oxygen treatment.
基金supported by national key program for developing basic science in China[grant number2012CB9557000]the "Strategy and Policies on Environment and Development in Western China" project of "China Council for International Cooperation on Environment and Development(CCICED)"
文摘This study aims to investigate the effect of the impact mechanism of climate change on the livestock production at small watershed level and county level with the Multi-level Model(MLM)in Qinghai Province.The result indicated that the gross livestock output value was greatly influenced by the climatic factors of the small watershed level.Higher temperature promoted also by the increase of precipitation,relative humidity and sunshine duration was found to be beneficial to the development of livestock production,except in some areas where temperature rise restrained the development of local livestock production to some degree when exceeding a certain level;besides,the impact of the socioeconomic factors on the livestock output value is obvious at the county level.The gross economic output measured with GDP has some inhibitory effects on the reinvestment of livestock production,while population growth promotes development of livestock production to some degree.The results not only provide scientific basis for the management of livestock production in Qinghai Province,but also provide reference for formulating the policies and adaptation measures targeted at climate change to promote the sustainable development of livestock production in other regions.
基金supported by the Behavioral and Social Research division of the National Institute on Aging(grant numbers 1-R21-AG031372-01,1-R01-AG037031-01,and 3-R01AG037031-03S1)the Natural Science Foundation of China(grant numbers 70910107022,71130002 and 71273237)+2 种基金the World Bank(contract numbers 7145915 and 7159234)the China Medical BoardPeking University.
文摘Background:Uneven economic development has led to substantial health inequalities between Chinese provinces.The extent of,and factors underlying,between-province health inequalities have received little attention.Methods:Data from 15,278 respondents in Wave 2(2013)of the China Health and Retirement Longitudinal Study(CHARLS)were used to investigate inequalities among people aged≥50 years in five health outcomes between 27 Chinese province-level administrative units.After characterizing the betweenprovince differences and the relevance of province effects,proportional change in variance between unadjusted and adjusted models was calculated to determine the percentage of between-province variance in health outcomes explained by province-level variables including measures of economic development and healthcare availability.Results:Although province effects explained<10%of overall variance in health outcomes,they underpinned large between-province inequalities among people aged≥50 years.Gross Regional Product per capita was more important than doctor density in explaining between-province variance in health outcomes,particularly depression symptoms and instrumental activities of daily living impairment.Conclusion:Policy efforts,including more equal distribution of healthcare personnel,may be warranted to reduce between-province health inequalities.
基金supported by Science and Technology Research Project of Henan Province(242102230078)Key Research Project of Higher Education Institutions of Henan Province(23A470002)Innovative Research Team of Henan Polytechnic University(T2020-3).
文摘Based on the experimental data of Mn_(1)Co_(0.5)Cr_(0.5)O_(x)catalysts and the component transport model in computational fluid dynamics(CFD),a kinetic model for the standard NH_(3)-SCR(NH_(3)selective catalytic reduction)process was effectively established.The objective of the model development was to predict the denitrification reaction rate of the catalyst,which incorporates various factors such as the Arrhenius parameters(pre-exponential factor and activation energy),inertial resistance,viscous resistance,and surface-to-volume ratio.To verify the practicability of the model,simulation results were compared with actual experimental data.The effects of NH_(3),NO,O_(2)concentrations,and gas hourly space velocity(GHSV)on NO conversion were simulated and analyzed.Subsequently,the NO conversion prediction model was trained and established using a combination of numerical simulation results,backpropagation neural network,and genetic algorithm(BP-GA).Furthermore,the significance of the impact that various factors had on the denitrification activity of the catalyst was determined.
基金financially supported by the Zhejiang Provin-cial Natural Science Foundation of China(No.LQ22E030016)the National Natural Science Foundation of China(Nos.52275137,51705467),the China Postdoctoral Science Foundation(No.2022M722831)+2 种基金the Postdoctoral Research Selected Funding Project of Zhejiang Province(No.ZJ2022063)the Self-Topic Fund of Zhe-jiang Normal University(No.2020ZS04)the National Key Re-search and Development Program of China(No.2018YFE0199100).
文摘In recent years,polymer-based triboelectric nanogenerators(TENGs)have been increasingly applied in the field of flexible wearable electronics.However,the lack of flame retardancy of existing TENGs greatly lim-its their applications in extreme circumstances.Herein,an ultra-thin and highly flexible aramid nanofiber(ANF)/MXene(Ti_(3)C_(2)T_(x))/Ni nanochain composite paper was prepared through vacuum-assisted filtration and freeze-drying technology.Owing to the synergistic effect between ANF and MXene,the composite paper not only possessed excellent mechanical properties,which were able to withstand over 10,000 times its own weight,but also exhibited outstanding flame-retardant and controllable Joule heating ca-pabilities.Moreover,the mechanical energy capture characteristics of the composite paper-based TENG were evaluated,resulting in the open-circuit voltage(55.6 V),short-circuit current(0.62μA),and trans-ferred charge quantity(25μC).It also could enable self-powering as a wearable electronic device with an instantaneous power of 15.6μW at the optimal external resistance of 10 MΩ.This work is intended to set TENG as safe energy harvesting devices for reducing fire hazards,and will provide a new strategy to broaden the application ranges of TENG.
基金support from the Program for the Development of Science and Technology of Jilin Province(Grant No.SKL202402004)the Jilin Province Major Science and Technology Program(Grant No.20240211002GX)the Open Research Fund of the Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education(Jilin Normal University,202405).
文摘Tin sulfide(SnS)is a promising non-toxic thermoelectric(TE)material to replace SnSe(Se is toxic),due to its similar structure and low thermal conductivity(k)comparable to SnSe.However,the poor electrical conductivity(s)of SnS results in lower TE performance.In this work,high pressure was utilized to regulate the electronic structure,thereby mediating the conflict of electron and phonon transport to optimize the TE performance.In situ measurements of thermoelectric properties for SnS under high pressure and high temperature revealed that although the Seebeck coefficient(S)and k slightly decrease with increasing pressure,the s dramatically increases with increasing pressure,finally increasing the dimensionless figure of merit(ZT).The s increases from 2135 S·m^(-1)to 83549 S·m^(-1)as the pressure increases from 1 GPa to 5 GPa at 325 K,representing an increase of an order of magnitude.The high s of SnS leads to an increase in the PF to 1436μW·m^(-1)·K^(-2)at 5 GPa and 652 K.The maximum ZT value of 0.77 at 5 GPa and 652 K was obtained,which is 4 times the maximum ZT under ambient pressure and is comparable to that of doped SnS.The increase in s is due to the fact that pressure modulates the band structure of SnS by narrowing the band gap from 1.013 eV to 0.712 eV.This study presents a valuable guide for searching new high TE performance materials using high pressure.
基金the National Natural Science Foundation of China(No.51475020)the National Key Basic Research Program of China(No.2014CB046400)
文摘As a kind of actuation mechanism for power-by-wire(PBW) actuation systems of more/all electrical aircraft, an electro-hydrostatic actuator(EHA) is a highly integrated local hydraulic actuation system. It is a volume control system consisting of a motor, a pump, an actuator, etc.,which has features of high efficiency and reliability. However, the poor dynamic characteristic is one of the main factors restricting its wide application in aircraft. In this paper, the reason for the poor dynamic characteristic of an EHA is revealed from the perspectives of the natural frequency characteristic and the power requirement, respectively. In other words, the insufficiency of the motor output power at a high frequency is the main factor causing the poor dynamic characteristic of the system, and methods which include increasing the maximum output torque of the motor, reducing the rotational inertia of the motor-pump group, and adopting a double-motorpump group configuration are proposed in this paper, by which the dynamic characteristic of the system can be improved. The feasibility of those methods are verified by simulations. Finally, the dynamic characteristic is tested on an EHA prototype, and results show that saturation of the output torque of the motor is the main factor restricting the dynamic characteristic of the EHA system.
基金This work was supported by the National Basic Research Project(973 program,2012CB518200)General Program(81371232,81573251)of the Natural Science Foundation of China+1 种基金Special Key Programs for Drug R&D of China(2012ZX09102301-016,2014ZX09J14107-05B)Foundation of Joint Research Center for Translational Medicine between Beijing Proteome Research Center and Tianjin Baodi Hospital(TMRC201301).
文摘Human wellness is the ultimate goal of our efforts in improving the human life.Special foods are undoubtedly important in achieving human wellness.However,overeating significantly leads to obesity and diabetes.These chronic diseases will in turn affect the human wellness.Therefore,“dietary restriction and proper exercise”were introduced in the human daily life.Different foods cause various effects on the human health.The diversification of diet is a priority for nutritionists to keep our body healthy.To avoid diabetes mellitus,special foods for ketogenic diet,low-carbon diet,and low-calorie intake are also gradually attracting attention.In addition,the hypothesis that“hunger sensation comes from gut flora”brings new light to the research on the biological motivation for humans to eat food.This hypothesis has been gradually demonstrated using the flexible fasting technology by providing special foods,such as plant polysaccharides and dietary fibers.The response to food-needing signals from the gut flora to these foods demonstrates the importance of the gut flora in improving human wellness.The gut flora is probably an essential factor for translating the food-eating signals and converting the nutrition to our body.Therefore,“gut flora priority principle”is developed to guarantee human wellness.The 16S rRNA sequencing and mass spectrometric techniques can be used to identify the gut flora,which may guide us to a new era of human wellness based on gut flora wellness.
基金the Manned Space Engineering Technology (No. ZS2020103001)the National Natural Science Foundation of China (No. 52006004)+1 种基金National Numerical Wind Tunnel Project of China (No. NNW2018-ZT3A05)the Open Fund of Key Laboratory of Icing and Anti/De-icing (No. IADL20190102)
文摘Under hypersonic flow conditions, the complicated gas-graphene interactions including surface catalysis and surface ablation would occur concurrently and intervene together with the thermodynamic response induced by spacecraft reentry. In this work, the competing effects of surface heterogeneous catalytic recombination and ablation characteristics at elevated temperatures are investigated using the Reactive Molecular Dynamics(RMD) simulation method. A GasSurface Interaction(GSI) model is established to simulate the collisions of hyper-enthalpy atomic oxygen on graphene films in the temperature range of 500–2500 K. A critical temperature Tcaround900 K is identified to distinguish the graphene responses into two parts: at T < T_(c), the heterogeneous surface catalysis dominates, while the surface ablation plays a leading role at T > T_(c). Contradicting to the traditional Arrhenius expression that the recombination coefficient increases with the increase of surface temperature, the value is found to be relatively uniform at T < T_(c) but declines sharply as the surface temperature increases further due to the competing ablation effect. The occurrence of surface ablation decreases the amounts of active sites on the graphene surface for oxygen adsorption, leading to reduced recombination coefficient from both Langmuir-Hinshelwood(L-H) and Eley-Rideal(E-R) mechanisms. It suggests that the traditional Computational Fluid Dynamics(CFD) simulation method, which relies on the Arrhenius-type catalysis model, would result in large discrepancies in predicting aerodynamic heat for carbon-based materials during reentry into strong aerodynamic thermal environment.
