The rapid development of electric vehicles and portable energy storage systems demands improvements in the energy density and cost-effectiveness of lithium-ion batteries,a domain in which Lithium-rich layered cathode(...The rapid development of electric vehicles and portable energy storage systems demands improvements in the energy density and cost-effectiveness of lithium-ion batteries,a domain in which Lithium-rich layered cathode(LLO)materials inherently excel.However,these materials face practical challenges,such as low initial Coulombic efficiency,inferior cycle/rate performance,and voltage decline during cycling,which limit practical application.Our study introduces a surface multi-component integration strategy that incorporates oxygen vacancies into the pristine LLO material Li1.2Mn_(0.6)Ni_(0.2)O_(2).This process involves a brief citric acid treatment followed by calcination,aiming to explore rate-dependent degradation behavior.The induced surface oxygen vacancies can reduce surface oxygen partial pressure and diminish the generation of O_(2)and other highly reactive oxygen species on the surface,thereby facilitating the activation of Li ions trapped in tetrahedral sites while overcoming transport barriers.Additionally,the formation of a spinel-like phase with 3D Li+diffusion channels significantly improves Li^(+)diffusion kinetics and stabilizes the surface structure.The optimally modified sample boasts a discharge capacity of 299.5 mA h g^(-1)at a 0.1 C and 251.6 mA h g^(-1)at a 1 C during the initial activation cycle,with an impressive capacity of 222.1 mA h g^(-1)at a 5 C.Most notably,it retained nearly 70%of its capacity after 300 cycles at this elevated rate.This straightforward,effective,and highly viable modification strategy provides a crucial resolution for overcoming challenges associated with LLO materials,making them more suitable for practical application.展开更多
In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relat...In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.展开更多
In this paper,a variety of classical convolutional neural networks are trained on two different datasets using transfer learning method.We demonstrated that the training dataset has a significant impact on the trainin...In this paper,a variety of classical convolutional neural networks are trained on two different datasets using transfer learning method.We demonstrated that the training dataset has a significant impact on the training results,in addition to the optimization achieved through the model structure.However,the lack of open-source agricultural data,combined with the absence of a comprehensive open-source data sharing platform,remains a substantial obstacle.This issue is closely related to the difficulty and high cost of obtaining high-quality agricultural data,the low level of education of most employees,underdeveloped distributed training systems and unsecured data security.To address these challenges,this paper proposes a novel idea of constructing an agricultural data sharing platform based on a federated learning(FL)framework,aiming to overcome the deficiency of high-quality data in agricultural field training.展开更多
Temperature and pressure play key roles in Global Navigation Satellite System(GNSS) precipitable water vapor(PWV) retrieval. The National Aeronautics and Space Administration(NASA) and European Center for Medium-Range...Temperature and pressure play key roles in Global Navigation Satellite System(GNSS) precipitable water vapor(PWV) retrieval. The National Aeronautics and Space Administration(NASA) and European Center for Medium-Range Weather Forecasts(ECMWF) have released their latest reanalysis product: the modern-era retrospective analysis for research and applications, version 2(MERRA-2) and the fifthgeneration ECMWF reanalysis(ERA5), respectively. Based on the reanalysis data, we evaluate and analyze the accuracy of the surface temperature and pressure products in China using the the measured temperature and pressure data from 609 ground meteorological stations in 2017 as reference values.Then the accuracy of the two datasets and their performances in estimating GNSS PWV are analyzed. The PWV derived from the pressure and temperature products of ERA5 and MERRA-2 has high accuracy. The annual average biases of pressure and temperature for ERA5 are-0.07 hPa and 0.45 K, with the root mean square error(RMSE) of 0.95 hPa and 2.04 K, respectively. The annual average biases of pressure and temperature for MERRA-2 are-0.01 hPa and 0.38 K, with the RMSE of 1.08 h Pa and 2.66 K, respectively.The accuracy of ERA5 is slightly higher than that of MERRA-2. The two reanalysis data show negative biases in most regions of China, with the highest to lowest accuracy in the following order: the south,north, northwest, and Tibet Plateau. Comparing the GNSS PWV calculated using MERRA-2(GNSS MERRA-2 PWV) and ERA5(GNSS ERA5 PWV) with the radiosonde-derived PWV from 48 co-located GNSS stations and the measured PWV of the co-location radiosonde stations, it is found that the accuracy of GNSS ERA5 PWV is better than that of GNSS MERRA-2 PWV. These results show the different applicability of surface temperature and pressure products from MERRA-2 and ERA5 data, indicating that both have important applications in meteorological research and GNSS water vapor monitoring in China.展开更多
Background During the transition period,the insufficient dry matter intake and a sharply increased in energy consumption to produce large quantities of milk,high yielding cows would enter a negative energy balance(NEB...Background During the transition period,the insufficient dry matter intake and a sharply increased in energy consumption to produce large quantities of milk,high yielding cows would enter a negative energy balance(NEB)that causes an increase in ketone bodies(KBs)and decrease in reproduction efficiency.The excess concentrations of circulating KBs,represented byβ-hydroxybutyric acid(BHBA),could lead to oxidative damage,which potentially cause injury to follicular granulosa cells(fGCs)and delayed follicular development.Sirtuin 3(Sirt3)regulates mitochondria reactive oxygen species(mitoROS)homeostasis in a beneficial manner;however,the molecular mechanisms underlying its involvement in the BHBA-induced injury of fGCs is poorly understood.The aim of this study was to explore the protection effects and underlying mechanisms of Sirt3 against BHBA overload-induced damage of fGCs.Results Our findings demonstrated that 2.4 mmol/L of BHBA stress increased the levels of mitoROS in bovine fGCs.Further investigations identified the subsequent mitochondrial dysfunction,including an increased abnormal rate of mitochondrial architecture,mitochondrial permeability transition pore(MPTP)opening,reductions in mitochondrial membrane potential(MMP)and Ca^(2+)release;these dysfunctions then triggered the caspase cascade reaction of apoptosis in fGCs.Notably,the overexpression of Sirt3 prior to treatment enhanced mitochondrial autophagy by increasing the expression levels of Beclin-1,thus preventing BHBA-induced mitochondrial oxidative stress and mitochondrial dysfunction in fGCs.Furthermore,our data suggested that the AMPK-mTOR-Beclin-1 pathway may be involved in the protective mechanism of Sirt3 against cellular injury triggered by BHBA stimulation.Conclusions These findings indicate that Sirt3 protects fGCs from BHBA-triggered injury by enhancing autophagy,attenuating oxidative stress and mitochondrial damage.This study provides new strategies to mitigate the fGCs injury caused by excessive BHBA stress in dairy cows with ketosis.展开更多
Numerical research is conducted to investigate the effects of plasma boundary shape on the tearing mode triggering explosive bursts in toroidal tokamak plasmas.In this work,m/n=2/1 mode is responsible for the triggeri...Numerical research is conducted to investigate the effects of plasma boundary shape on the tearing mode triggering explosive bursts in toroidal tokamak plasmas.In this work,m/n=2/1 mode is responsible for the triggering of the explosive burst.Plasma boundary shape can be adjusted via the adjustment of the parameters triangularityδand elongationκ.The investigations are conducted both under lowβ(close to zero)and under finiteβregimes.In the lowβregime,triangularity and elongation both have stabilizing effect on the explosive burst,and the stabilizing effect of elongation is stronger.Under a large elongation(κ=2.0),the elongation effect can evidently enhance the stabilizing effect in a positive triangularity regime,but barely affects the stabilizing effect in a negative triangularity regime.In the finiteβregime,the explosive burst is delayed in comparison with that in the lowβregime.Similar to the lowβcases,the effects of triangularity and elongation both are stabilizing.Under a large elongation(κ=2.0),the elongation effect can evidently enhance the stabilizing effect on the explosive burst in a positive triangularity regime,but impair the stabilizing effect in a negative triangularity regime.The explosive burst disappears in the large triangularity case(δ=0.5),indicating that the explosive burst can be effectively prevented in experiments via carefully adjusting plasma boundary shape.Moreover,strong magnetic stochasticity appears in the negative triangularity case during the nonlinear phase.展开更多
Background:Improving feed efficiency(FE)is one of the main objectives in broiler breeding.It is difficult to directly measure FE traits,and breeders hence have been trying to identify biomarkers for the indirect selec...Background:Improving feed efficiency(FE)is one of the main objectives in broiler breeding.It is difficult to directly measure FE traits,and breeders hence have been trying to identify biomarkers for the indirect selection and improvement of FE traits.Metabolome is the"bridge"between genome and phenome.The metabolites may potentially account for more of the phenotypic variation and can suitably serve as biomarkers for selecting FE traits.This study aimed to identify plasma metabolite markers for selecting high-FE broilers.A total of 441 birds from Northeast Agricultural University broiler lines divergently selected for abdominal fat content were used to analyze plasma metabolome and estimate the genetic parameters of differentially expressed metabolites.Results:The results identified 124 differentially expressed plasma metabolites(P<0.05)between the lean line(highFE birds)and the fat line(low-FE birds).Among these differentially expressed plasma metabolites,44 were found to have higher positive or negative genetic correlations with FE traits(|r_g|≥0.30).Of these 44 metabolites,14 were found to display moderate to high heritability estimates(h~2≥0.20).However,among the 14 metabolites,4 metabolites whose physiological functions have not been reported were excluded.Ultimately,10 metabolites were suggested to serve as the potential biomarkers for breeding the high-FE broilers.Based on the physiological functions of these metabolites,reducing inflammatory and improving immunity were proposed to improve FE and increase production efficiency.Conclusions:According to the pipeline for the selection of the metabolite markers established in this study,it was suggested that 10 metabolites including 7-ketocholesterol,dimethyl sulfone,epsilon-(gamma-glutamyl)-lysine,gamma-glutamyltyrosine,2-oxoadipic acid,L-homoarginine,testosterone,adenosine 5'-monophosphate,adrenic acid,and calcitriol could be used as the potential biomarkers for breeding the"food-saving broilers".展开更多
Fiber laser is a fundamental component of laser systems and is of great significance for development of laser technology.Its pulse output can be divided into Q-switched and mode-locked.Achieving ultrashort pulse with ...Fiber laser is a fundamental component of laser systems and is of great significance for development of laser technology.Its pulse output can be divided into Q-switched and mode-locked.Achieving ultrashort pulse with narrower pulse duration and higher power is the focus of current research on mode-locked lasers.As an important component of fiber laser systems,saturable absorber(SA) can modulate losses in the optical cavity and generate pulses,enabling the laser system to achieve pulse output under long-term normal operating conditions better.Therefore,expanding the selection range of materials with better saturable absorption properties to improve the quality of pulse output is an important topic in current research.Here,the second generation topological insulator Bi_(2)Te_(3) single crystal is prepared,and a ring fiber laser system is built with the Bi_(2)Te_(3) SA.The mode-locked pulse with a pulse duration of 288 fs and a signal-to-noise ratio of 80.202 dB is realized.This result verifies that Bi_(2)Te_(3),as a member of topological insulator,has good saturable absorption characteristics,and has broad prospects for the application research in lasers.展开更多
在涉及多群体样本的医学研究中,群体遗传结构差异是不容忽视的影响因素之一。利用族源信息单核苷酸多态性遗传标记(ancestry-informative single nucleotide polymorphism,AI-SNP),通过分析群体遗传成分、推断个体遗传背景并对群体样本...在涉及多群体样本的医学研究中,群体遗传结构差异是不容忽视的影响因素之一。利用族源信息单核苷酸多态性遗传标记(ancestry-informative single nucleotide polymorphism,AI-SNP),通过分析群体遗传成分、推断个体遗传背景并对群体样本进行预筛选,可以有效降低群体遗传结构差异对医学研究影响。鉴于已发表的研究多为解析大陆间、大陆次级区域间的群体遗传结构差异,本研究拟基于千人基因组计划(GRCh37.p13)中东亚五群体:日本东京群体(Japanese in Tokyo,JPT)、北京汉族(Han Chinese in Beijing,CHB)、南方汉族(Southern Han Chinese,CHS)、西双版纳傣族(Chinese Dai in Xishuangbanna,CDX)、越南京族(Kinh in Ho Chi Minh City,KHV)的数据,以FST值为标准筛选AI-SNP并分析大陆次级区域内群体遗传结构差异。结果表明,研究涉及的东亚群体可分为三簇:JPT、CHB和CHS、CDX和KHV。利用AI-SNP可成功解析个体的遗传背景,而群体代表性遗传成分占比超过80%的个体具有良好的群体代表性。本研究表明,基于FST值筛选一组AI-SNP用于核验样本遗传背景、筛选群体代表性样本的方法在降低大陆次级区域内群体遗传结构差异对群体相关医学研究的影响中具有实际应用价值。展开更多
Real-time monitoring and wireless transmission of farmland soil moisture have been paid with more and more attention in the research of agricultural drought monitoring, early warning and prevention and control technol...Real-time monitoring and wireless transmission of farmland soil moisture have been paid with more and more attention in the research of agricultural drought monitoring, early warning and prevention and control technology. The hardware design and software design of soil moisture monitoring in farmland were carried out, and a monitoring system based on the principles of ZigBee and GPRS technologies was developed and applied to the actual monitoring of soil moisture in farmland. This study provides a good idea to promote real-time monitoring, wireless transmission and intelligent management of soil moisture in farmland.展开更多
Background Atrial fibrillation(AF)is the most common sustained cardiac arrhythmia that can cause severe heart problems.Catheter ablation is one of the most ideal procedures for the treatment of AF.Physicians qualified...Background Atrial fibrillation(AF)is the most common sustained cardiac arrhythmia that can cause severe heart problems.Catheter ablation is one of the most ideal procedures for the treatment of AF.Physicians qualified to perform this procedure need to be highly skilled in manipulating the relevant surgical devices.This study proposes an interactive surgical simulator with high fidelity to facilitate efficient training and low-cost medical education.Methods We used a shared centerline model to simulate the interaction between multiple surgical devices.An improved adaptive deviation-feedback approach is proposed to accelerate the convergence of each iteration.The periodical beating of the human heart was also simulated in real time using the position-based dynamics(PBD)framework to achieve higher fidelity.We then present a novel method for handling the interaction between the devices and the beating heart mesh model.Experiments were conducted in a homemade simulator prototype to evaluate the robustness,performance,and flexibility of the proposed method.Preliminary evaluation of the simulator was performed by medical students,residents,and surgeons.Results The interaction between surgical devices,static vascular meshes,and beating heart mesh was stably simulated in a frame rate suitable for interaction.Conclusion Our simulator is capable of simulating the procedure of catheter ablation with high fidelity and provides immersive visual experiences and haptic feedback.展开更多
In this study, graphene sheets are prepared under a hydrogen atmosphere without a catalyst, and the growth mechanism of graphene by direct current arc discharge is investigated experimentally and numerically. The size...In this study, graphene sheets are prepared under a hydrogen atmosphere without a catalyst, and the growth mechanism of graphene by direct current arc discharge is investigated experimentally and numerically. The size and layer numbers of graphene sheets increase with the arc current.Distributions of temperature, velocity, and mass fraction of carbon are obtained through numerical simulations. A high current corresponds to a high saturation temperature, evaporation rate, and mass density of carbon clusters. When the carbon vapor is saturated, the saturation temperatures are 3274.9, 3313.9, and 3363.6 K, and the mass densities are 6.4×1022,8.42×1022, and 1.23×1023 m-3 under currents of 150, 200, and 250 A, respectively. A hydrogen-induced marginal growth model is used to explain the growth mechanism. Under a high current, the condensation coefficient and van der Waals force increase owing to the higher saturation temperature and mass density of carbon clusters, which is consistent with experimental results.展开更多
This paper is concerned with the Fisher-KPP equation with diffusion and nonlocal delay.Firstly,we establish the global existence and uniform boundedness of solutions to the Cauchy problem.Then,we establish the spreadi...This paper is concerned with the Fisher-KPP equation with diffusion and nonlocal delay.Firstly,we establish the global existence and uniform boundedness of solutions to the Cauchy problem.Then,we establish the spreading speed for the solutions with compactly supported initial data.Finally,we investigate the long time behavior of solutions by numerical simulations.展开更多
According to the current researches,we could say microwave radiation can cause heart damage.Autophagy plays an important role in the process of heart disease and injury,however,the effects induced by microwave radiati...According to the current researches,we could say microwave radiation can cause heart damage.Autophagy plays an important role in the process of heart disease and injury,however,the effects induced by microwave radiation of different frequencies in a rat's heart are still unclear,which are dose-dependent,frequency-dependent and accumulative.So the answer of autophagy influencing myocardial injury induced by microwave remains uncertainty.In our research,we adopted three methods of microwave to observe the results:different power density microwave with the same frequency,different frequency microwave with the same power density and the accumulative effects of two frequency microwaves with the same power density.Based on the experimental result,abnormal electrocardiograms and serum myocardial enzymes were found in the 10 m W/cm^(2)single frequency microwave groups and accumulative groups.展开更多
In order to provide theoretical basis and technical support for the afforestation and artificial water supply of P.szechuanica in arid areas,the characteristics of water consumption of P.szechuanica were explored,and ...In order to provide theoretical basis and technical support for the afforestation and artificial water supply of P.szechuanica in arid areas,the characteristics of water consumption of P.szechuanica were explored,and the law of water demand of P.szechuanica was grasped.In this paper,potted seedlings of 1-0 rooted cuttings of P.szechuanica were taken as research objects,and change situation of water consumption under different water control gradients was measured regularly by using weighing method,further analyzing dynamic change of water consumption of P.szechuanica and revealing water demand law of 1-0 rooted cuttings of P.szechuanica.The results showed that total change of water consumption of 1-0 rooted cuttings of P.szechuanica had"slow-fast-slow-fast"double-peak trend in the growth period of the current year,and corresponded with univariate linear relation(R^(2)=0.7137),with significant difference.In whole growth period,water consumption in August was the highest,which was 2.7 times of that in June and July and 1.5 times of that after September.In different water control treatments,the dynamic changes of daily and monthly water consumption were significantly different.In seven water control treatments,monthly water consumption was between(6315.95±1690.70)and(10105.28±3065.30)g/month,and mean was(8211.07±2308.23)g/month.With intensification of water control treatment,water consumption increased,but there was no seedling death due to water shortage.P.szechuanica has great plasticity in water demand,and can survive in both arid and humid environments.Meanwhile,it is revealed that P.szechuanica is the most widely distributed tree species in the region.展开更多
A bentonite & PAM particle flocculation system was employed in recycled fiber pulp wastewater treatment in this paper. The optimum conditions of the adsorption & coagulation treatment was explored and optimize...A bentonite & PAM particle flocculation system was employed in recycled fiber pulp wastewater treatment in this paper. The optimum conditions of the adsorption & coagulation treatment was explored and optimized and effects of the treatment were focused on, especially stickies substances removal. Under the optimal conditions, the removal of MTBE extract and cationic demand reached 91.26% and 86.93%, and the average particle size in the treated wastewater pollutants is reduced from 40.95μm to 0.5μm. In this treatment the removal of CODcr, turbidity, SS and color were 89.67%, 99.56%, 95.58% and 93.08%, respectively. The results showed that the particle flocculation system was effective for the treatment of recycled fiber pulp wastewater, especially for controlling the stickies.展开更多
基金supported by the National Key R&D Program of China(2021YFB2401800)the National Natural Science Foundation of China(21875022,22179008)+4 种基金the Yibin‘Jie Bang Gua Shuai’(2022JB004)the support from the Beijing Nova Program(20230484241)the support from the Postdoctoral Fellowship Program of CPSF(GZB20230931)the support from the 4B7B beam line of Beijing Synchrotron Radiation Facility(2021-BEPC-PT-005924,2021-BEPC-PT-005967)BL08U1A beam line of Shanghai Synchrotron Radiation Facility(2021-SSRF-PT-017710)。
文摘The rapid development of electric vehicles and portable energy storage systems demands improvements in the energy density and cost-effectiveness of lithium-ion batteries,a domain in which Lithium-rich layered cathode(LLO)materials inherently excel.However,these materials face practical challenges,such as low initial Coulombic efficiency,inferior cycle/rate performance,and voltage decline during cycling,which limit practical application.Our study introduces a surface multi-component integration strategy that incorporates oxygen vacancies into the pristine LLO material Li1.2Mn_(0.6)Ni_(0.2)O_(2).This process involves a brief citric acid treatment followed by calcination,aiming to explore rate-dependent degradation behavior.The induced surface oxygen vacancies can reduce surface oxygen partial pressure and diminish the generation of O_(2)and other highly reactive oxygen species on the surface,thereby facilitating the activation of Li ions trapped in tetrahedral sites while overcoming transport barriers.Additionally,the formation of a spinel-like phase with 3D Li+diffusion channels significantly improves Li^(+)diffusion kinetics and stabilizes the surface structure.The optimally modified sample boasts a discharge capacity of 299.5 mA h g^(-1)at a 0.1 C and 251.6 mA h g^(-1)at a 1 C during the initial activation cycle,with an impressive capacity of 222.1 mA h g^(-1)at a 5 C.Most notably,it retained nearly 70%of its capacity after 300 cycles at this elevated rate.This straightforward,effective,and highly viable modification strategy provides a crucial resolution for overcoming challenges associated with LLO materials,making them more suitable for practical application.
文摘In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.
基金National Key Research and Development Program of China(2021ZD0113704).
文摘In this paper,a variety of classical convolutional neural networks are trained on two different datasets using transfer learning method.We demonstrated that the training dataset has a significant impact on the training results,in addition to the optimization achieved through the model structure.However,the lack of open-source agricultural data,combined with the absence of a comprehensive open-source data sharing platform,remains a substantial obstacle.This issue is closely related to the difficulty and high cost of obtaining high-quality agricultural data,the low level of education of most employees,underdeveloped distributed training systems and unsecured data security.To address these challenges,this paper proposes a novel idea of constructing an agricultural data sharing platform based on a federated learning(FL)framework,aiming to overcome the deficiency of high-quality data in agricultural field training.
基金the National Natural Science Foundation of China(Grant No.42204006)the Guangxi Natural Science Foundation of China(2020GXNSFBA297145)+1 种基金the“Ba Gui Scholars”program of the provincial government of Guangxi,and Innovation Project of GuangXi Graduate Education(Grant No.YCSW2022322)Open Research Fund Program of the Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,China(GrantNo.20-01-03,21-01-04)
文摘Temperature and pressure play key roles in Global Navigation Satellite System(GNSS) precipitable water vapor(PWV) retrieval. The National Aeronautics and Space Administration(NASA) and European Center for Medium-Range Weather Forecasts(ECMWF) have released their latest reanalysis product: the modern-era retrospective analysis for research and applications, version 2(MERRA-2) and the fifthgeneration ECMWF reanalysis(ERA5), respectively. Based on the reanalysis data, we evaluate and analyze the accuracy of the surface temperature and pressure products in China using the the measured temperature and pressure data from 609 ground meteorological stations in 2017 as reference values.Then the accuracy of the two datasets and their performances in estimating GNSS PWV are analyzed. The PWV derived from the pressure and temperature products of ERA5 and MERRA-2 has high accuracy. The annual average biases of pressure and temperature for ERA5 are-0.07 hPa and 0.45 K, with the root mean square error(RMSE) of 0.95 hPa and 2.04 K, respectively. The annual average biases of pressure and temperature for MERRA-2 are-0.01 hPa and 0.38 K, with the RMSE of 1.08 h Pa and 2.66 K, respectively.The accuracy of ERA5 is slightly higher than that of MERRA-2. The two reanalysis data show negative biases in most regions of China, with the highest to lowest accuracy in the following order: the south,north, northwest, and Tibet Plateau. Comparing the GNSS PWV calculated using MERRA-2(GNSS MERRA-2 PWV) and ERA5(GNSS ERA5 PWV) with the radiosonde-derived PWV from 48 co-located GNSS stations and the measured PWV of the co-location radiosonde stations, it is found that the accuracy of GNSS ERA5 PWV is better than that of GNSS MERRA-2 PWV. These results show the different applicability of surface temperature and pressure products from MERRA-2 and ERA5 data, indicating that both have important applications in meteorological research and GNSS water vapor monitoring in China.
基金supported by the National Natural Science Foundation of China(32102549)the National Key R&D Program of Ningxia(2021BEF02023)+2 种基金the earmarked fund for CARS(CARS-36)the Agricultural Science and Technology Innovation Program(ASTIP-IAS06)the National Key R&D Program of Gansu(21YF5NJ196)。
文摘Background During the transition period,the insufficient dry matter intake and a sharply increased in energy consumption to produce large quantities of milk,high yielding cows would enter a negative energy balance(NEB)that causes an increase in ketone bodies(KBs)and decrease in reproduction efficiency.The excess concentrations of circulating KBs,represented byβ-hydroxybutyric acid(BHBA),could lead to oxidative damage,which potentially cause injury to follicular granulosa cells(fGCs)and delayed follicular development.Sirtuin 3(Sirt3)regulates mitochondria reactive oxygen species(mitoROS)homeostasis in a beneficial manner;however,the molecular mechanisms underlying its involvement in the BHBA-induced injury of fGCs is poorly understood.The aim of this study was to explore the protection effects and underlying mechanisms of Sirt3 against BHBA overload-induced damage of fGCs.Results Our findings demonstrated that 2.4 mmol/L of BHBA stress increased the levels of mitoROS in bovine fGCs.Further investigations identified the subsequent mitochondrial dysfunction,including an increased abnormal rate of mitochondrial architecture,mitochondrial permeability transition pore(MPTP)opening,reductions in mitochondrial membrane potential(MMP)and Ca^(2+)release;these dysfunctions then triggered the caspase cascade reaction of apoptosis in fGCs.Notably,the overexpression of Sirt3 prior to treatment enhanced mitochondrial autophagy by increasing the expression levels of Beclin-1,thus preventing BHBA-induced mitochondrial oxidative stress and mitochondrial dysfunction in fGCs.Furthermore,our data suggested that the AMPK-mTOR-Beclin-1 pathway may be involved in the protective mechanism of Sirt3 against cellular injury triggered by BHBA stimulation.Conclusions These findings indicate that Sirt3 protects fGCs from BHBA-triggered injury by enhancing autophagy,attenuating oxidative stress and mitochondrial damage.This study provides new strategies to mitigate the fGCs injury caused by excessive BHBA stress in dairy cows with ketosis.
基金supported by the National Natural Science Foundation of China(Grant Nos.11925501,12105034,and 12205034)the Fundamental Research Funds for the Central Universities(Grant Nos.DUT22ZD215)。
文摘Numerical research is conducted to investigate the effects of plasma boundary shape on the tearing mode triggering explosive bursts in toroidal tokamak plasmas.In this work,m/n=2/1 mode is responsible for the triggering of the explosive burst.Plasma boundary shape can be adjusted via the adjustment of the parameters triangularityδand elongationκ.The investigations are conducted both under lowβ(close to zero)and under finiteβregimes.In the lowβregime,triangularity and elongation both have stabilizing effect on the explosive burst,and the stabilizing effect of elongation is stronger.Under a large elongation(κ=2.0),the elongation effect can evidently enhance the stabilizing effect in a positive triangularity regime,but barely affects the stabilizing effect in a negative triangularity regime.In the finiteβregime,the explosive burst is delayed in comparison with that in the lowβregime.Similar to the lowβcases,the effects of triangularity and elongation both are stabilizing.Under a large elongation(κ=2.0),the elongation effect can evidently enhance the stabilizing effect on the explosive burst in a positive triangularity regime,but impair the stabilizing effect in a negative triangularity regime.The explosive burst disappears in the large triangularity case(δ=0.5),indicating that the explosive burst can be effectively prevented in experiments via carefully adjusting plasma boundary shape.Moreover,strong magnetic stochasticity appears in the negative triangularity case during the nonlinear phase.
基金the earmarked fund for CARS-41,National Natural Science Foundation(32102537)White Feather Broiler Breeding Joint Project of the Ministry of Agriculture and Rural Affairs in China(19190526)“Academic Backbone”Project of Northeast Agricultural University(20XG30)。
文摘Background:Improving feed efficiency(FE)is one of the main objectives in broiler breeding.It is difficult to directly measure FE traits,and breeders hence have been trying to identify biomarkers for the indirect selection and improvement of FE traits.Metabolome is the"bridge"between genome and phenome.The metabolites may potentially account for more of the phenotypic variation and can suitably serve as biomarkers for selecting FE traits.This study aimed to identify plasma metabolite markers for selecting high-FE broilers.A total of 441 birds from Northeast Agricultural University broiler lines divergently selected for abdominal fat content were used to analyze plasma metabolome and estimate the genetic parameters of differentially expressed metabolites.Results:The results identified 124 differentially expressed plasma metabolites(P<0.05)between the lean line(highFE birds)and the fat line(low-FE birds).Among these differentially expressed plasma metabolites,44 were found to have higher positive or negative genetic correlations with FE traits(|r_g|≥0.30).Of these 44 metabolites,14 were found to display moderate to high heritability estimates(h~2≥0.20).However,among the 14 metabolites,4 metabolites whose physiological functions have not been reported were excluded.Ultimately,10 metabolites were suggested to serve as the potential biomarkers for breeding the high-FE broilers.Based on the physiological functions of these metabolites,reducing inflammatory and improving immunity were proposed to improve FE and increase production efficiency.Conclusions:According to the pipeline for the selection of the metabolite markers established in this study,it was suggested that 10 metabolites including 7-ketocholesterol,dimethyl sulfone,epsilon-(gamma-glutamyl)-lysine,gamma-glutamyltyrosine,2-oxoadipic acid,L-homoarginine,testosterone,adenosine 5'-monophosphate,adrenic acid,and calcitriol could be used as the potential biomarkers for breeding the"food-saving broilers".
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB4601101)the Beijing Natural Science Foundation(Grant No.JQ21019)the National Natural Science Foundation of China(Grant Nos.11975001,12075034,and 12261131495)。
文摘Fiber laser is a fundamental component of laser systems and is of great significance for development of laser technology.Its pulse output can be divided into Q-switched and mode-locked.Achieving ultrashort pulse with narrower pulse duration and higher power is the focus of current research on mode-locked lasers.As an important component of fiber laser systems,saturable absorber(SA) can modulate losses in the optical cavity and generate pulses,enabling the laser system to achieve pulse output under long-term normal operating conditions better.Therefore,expanding the selection range of materials with better saturable absorption properties to improve the quality of pulse output is an important topic in current research.Here,the second generation topological insulator Bi_(2)Te_(3) single crystal is prepared,and a ring fiber laser system is built with the Bi_(2)Te_(3) SA.The mode-locked pulse with a pulse duration of 288 fs and a signal-to-noise ratio of 80.202 dB is realized.This result verifies that Bi_(2)Te_(3),as a member of topological insulator,has good saturable absorption characteristics,and has broad prospects for the application research in lasers.
文摘在涉及多群体样本的医学研究中,群体遗传结构差异是不容忽视的影响因素之一。利用族源信息单核苷酸多态性遗传标记(ancestry-informative single nucleotide polymorphism,AI-SNP),通过分析群体遗传成分、推断个体遗传背景并对群体样本进行预筛选,可以有效降低群体遗传结构差异对医学研究影响。鉴于已发表的研究多为解析大陆间、大陆次级区域间的群体遗传结构差异,本研究拟基于千人基因组计划(GRCh37.p13)中东亚五群体:日本东京群体(Japanese in Tokyo,JPT)、北京汉族(Han Chinese in Beijing,CHB)、南方汉族(Southern Han Chinese,CHS)、西双版纳傣族(Chinese Dai in Xishuangbanna,CDX)、越南京族(Kinh in Ho Chi Minh City,KHV)的数据,以FST值为标准筛选AI-SNP并分析大陆次级区域内群体遗传结构差异。结果表明,研究涉及的东亚群体可分为三簇:JPT、CHB和CHS、CDX和KHV。利用AI-SNP可成功解析个体的遗传背景,而群体代表性遗传成分占比超过80%的个体具有良好的群体代表性。本研究表明,基于FST值筛选一组AI-SNP用于核验样本遗传背景、筛选群体代表性样本的方法在降低大陆次级区域内群体遗传结构差异对群体相关医学研究的影响中具有实际应用价值。
基金Supported by Special Scientific Research Fund of Meteorology in the Public Welfare Profession of China(GYHY201306046-05)
文摘Real-time monitoring and wireless transmission of farmland soil moisture have been paid with more and more attention in the research of agricultural drought monitoring, early warning and prevention and control technology. The hardware design and software design of soil moisture monitoring in farmland were carried out, and a monitoring system based on the principles of ZigBee and GPRS technologies was developed and applied to the actual monitoring of soil moisture in farmland. This study provides a good idea to promote real-time monitoring, wireless transmission and intelligent management of soil moisture in farmland.
基金the National Natural Science Foundation of China(61672510)the Shenzhen Basic Research Program(JCYJ20180507182441903).
文摘Background Atrial fibrillation(AF)is the most common sustained cardiac arrhythmia that can cause severe heart problems.Catheter ablation is one of the most ideal procedures for the treatment of AF.Physicians qualified to perform this procedure need to be highly skilled in manipulating the relevant surgical devices.This study proposes an interactive surgical simulator with high fidelity to facilitate efficient training and low-cost medical education.Methods We used a shared centerline model to simulate the interaction between multiple surgical devices.An improved adaptive deviation-feedback approach is proposed to accelerate the convergence of each iteration.The periodical beating of the human heart was also simulated in real time using the position-based dynamics(PBD)framework to achieve higher fidelity.We then present a novel method for handling the interaction between the devices and the beating heart mesh model.Experiments were conducted in a homemade simulator prototype to evaluate the robustness,performance,and flexibility of the proposed method.Preliminary evaluation of the simulator was performed by medical students,residents,and surgeons.Results The interaction between surgical devices,static vascular meshes,and beating heart mesh was stably simulated in a frame rate suitable for interaction.Conclusion Our simulator is capable of simulating the procedure of catheter ablation with high fidelity and provides immersive visual experiences and haptic feedback.
基金supported by National Natural Science Foundation of China (No. 11765010)the National Key Research and Development Program of China (No. 2019YFC1907900)+2 种基金the Applied Basic Research Programs of Yunnan Provincial Science and Technology Department (No. 202001AW070004)the Freely Exploring Fund for Academicians in Yunnan Province (No. 2018HA006)the Key Laboratory of Resource Chemistry, Ministry of Education (No. KLRCME2001)
文摘In this study, graphene sheets are prepared under a hydrogen atmosphere without a catalyst, and the growth mechanism of graphene by direct current arc discharge is investigated experimentally and numerically. The size and layer numbers of graphene sheets increase with the arc current.Distributions of temperature, velocity, and mass fraction of carbon are obtained through numerical simulations. A high current corresponds to a high saturation temperature, evaporation rate, and mass density of carbon clusters. When the carbon vapor is saturated, the saturation temperatures are 3274.9, 3313.9, and 3363.6 K, and the mass densities are 6.4×1022,8.42×1022, and 1.23×1023 m-3 under currents of 150, 200, and 250 A, respectively. A hydrogen-induced marginal growth model is used to explain the growth mechanism. Under a high current, the condensation coefficient and van der Waals force increase owing to the higher saturation temperature and mass density of carbon clusters, which is consistent with experimental results.
基金Supported by National Natural Science Foundation of China(12071193,11731005)。
文摘This paper is concerned with the Fisher-KPP equation with diffusion and nonlocal delay.Firstly,we establish the global existence and uniform boundedness of solutions to the Cauchy problem.Then,we establish the spreading speed for the solutions with compactly supported initial data.Finally,we investigate the long time behavior of solutions by numerical simulations.
文摘According to the current researches,we could say microwave radiation can cause heart damage.Autophagy plays an important role in the process of heart disease and injury,however,the effects induced by microwave radiation of different frequencies in a rat's heart are still unclear,which are dose-dependent,frequency-dependent and accumulative.So the answer of autophagy influencing myocardial injury induced by microwave remains uncertainty.In our research,we adopted three methods of microwave to observe the results:different power density microwave with the same frequency,different frequency microwave with the same power density and the accumulative effects of two frequency microwaves with the same power density.Based on the experimental result,abnormal electrocardiograms and serum myocardial enzymes were found in the 10 m W/cm^(2)single frequency microwave groups and accumulative groups.
基金Supported by Natural Science Foundation of Tibet Autonomous Region(XZ2019ZRG-58)Forestry Discipline Innovation Team Construction Project of Tibet Agriculture&Animal Husbandry University(Tibet Financial Forecast:2020-001).
文摘In order to provide theoretical basis and technical support for the afforestation and artificial water supply of P.szechuanica in arid areas,the characteristics of water consumption of P.szechuanica were explored,and the law of water demand of P.szechuanica was grasped.In this paper,potted seedlings of 1-0 rooted cuttings of P.szechuanica were taken as research objects,and change situation of water consumption under different water control gradients was measured regularly by using weighing method,further analyzing dynamic change of water consumption of P.szechuanica and revealing water demand law of 1-0 rooted cuttings of P.szechuanica.The results showed that total change of water consumption of 1-0 rooted cuttings of P.szechuanica had"slow-fast-slow-fast"double-peak trend in the growth period of the current year,and corresponded with univariate linear relation(R^(2)=0.7137),with significant difference.In whole growth period,water consumption in August was the highest,which was 2.7 times of that in June and July and 1.5 times of that after September.In different water control treatments,the dynamic changes of daily and monthly water consumption were significantly different.In seven water control treatments,monthly water consumption was between(6315.95±1690.70)and(10105.28±3065.30)g/month,and mean was(8211.07±2308.23)g/month.With intensification of water control treatment,water consumption increased,but there was no seedling death due to water shortage.P.szechuanica has great plasticity in water demand,and can survive in both arid and humid environments.Meanwhile,it is revealed that P.szechuanica is the most widely distributed tree species in the region.
文摘A bentonite & PAM particle flocculation system was employed in recycled fiber pulp wastewater treatment in this paper. The optimum conditions of the adsorption & coagulation treatment was explored and optimized and effects of the treatment were focused on, especially stickies substances removal. Under the optimal conditions, the removal of MTBE extract and cationic demand reached 91.26% and 86.93%, and the average particle size in the treated wastewater pollutants is reduced from 40.95μm to 0.5μm. In this treatment the removal of CODcr, turbidity, SS and color were 89.67%, 99.56%, 95.58% and 93.08%, respectively. The results showed that the particle flocculation system was effective for the treatment of recycled fiber pulp wastewater, especially for controlling the stickies.