Design and analysis of an advanced thermal management system for the solar close observations and proximity experiments spacecraft

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.

Boosting rate performance of layered lithium-rich cathode materials by oxygen vacancy induced surface multicomponent integration

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.

Experimental and numerical simulation study on forced ventilation and dust removal of coal mine heading surface

In order to study the problems of unreasonable airflow distribution and serious dust pollution in a heading surface,an experimental platform for forced ventilation and dust removal was built based on the similar principles.Through the similar experiment and numerical simulation,the distribution of airflow field in the roadway and the spatial and temporal evolution of dust pollution under the conditions of forced ventilation were determined.The airflow field in the roadway can be divided into three zones:jet zone,vortex zone and reflux zone.The dust concentration gradually decreases from the head to the rear of the roadway.Under the forced ventilation conditions,there is a unilateral accumulation of dust,with higher dust concentrations away from the ducts.The position of the equipment has an interception effect on the dust.The maximum error between the test value and the simulation result is 12.9%,which verifies the accuracy of the experimental results.The research results can provide theoretical guidance for the application of dust removal technology in coal mine.

Synaptic Transmission of Primary Hippocampal Neurons was Enhanced after Terahertz Waves Exposure

Terahertz(THz)waves,also known as T-rays,encompass frequencies ranging from 0.1 to 10 THz and possess unique properties that render them applicable in various biomedical domains,particularly in neurobiology[1].Synaptic transmission,the process through which signals propagate between neurons at synapses,is pivotal for brain function and information processing.

A Novel Agricultural Data Sharing Mode Based on Rice Disease Identification

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.

Evaluation of surface temperature and pressure derived from MERRA-2 and ERA5 reanalysis datasets and their applications in hourly GNSS precipitable water vapor retrieval over China

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.

Sirtuin 3 regulation:a target to alleviateβ-hydroxybutyric acid-induced mitochondrial dysfunction in bovine granulosa cells

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.

Effects of Plasma Boundary Shape on Explosive Bursts Triggered by Tearing Mode in Toroidal Tokamak Plasmas with Reversed Magnetic Shear

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.

Identification of biomarkers associated with the feed efficiency by metabolomics profiling:results from the broiler lines divergent for high or low abdominal fat content

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".

Preparation of Bi_(2)Te_(3) Based on Saturable Absorption System and Its Application in Fiber Lasers

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.

聚己内酯增强生物基聚酯弹性体

针对生物基聚酯弹性体(BEE)力学性能较差的问题,采用聚己内酯(PCL)作为BEE的增强相,通过溶液共混及橡胶传统硫化工艺,制备了具有较高力学性能的生物基BEE/PCL硫化胶。通过动态力学性能、扫描电镜、差示扫描量热法、X射线衍射、力学性能测试等,对BEE/PCL硫化胶的相容性、微观相态、热性能及结晶性能、力学性能进行了表征。BEE/PCL硫化胶只有1个玻璃化转变温度,为热力学相容体系,但扫描电镜分析结果表明,BEE/PCL硫化胶为微观相分离体系。随着PCL含量的增加,BEE/PCL硫化胶的结晶度逐渐增加,拉伸强度逐渐增加,断裂伸长率先增加后降低。研究发现,当BEE与PCL的质量比为8∶2,BEE/PCL硫化胶的力学性能较优,拉伸强度为5.1 MPa、断裂伸长率为292%。

微单倍型遗传标记的法医基因组学研究

微单倍型(microhaplotype,MH)是在一定DNA片段范围之内,由至少两个单核苷酸多态性位点组成的遗传标记。MH兼具无stutter伪峰、多态性丰富以及扩增子较小等特点,有望成为法医学上的一种新型遗传标记。为了从全基因组维度上分析MH的特征,进一步发掘其应用潜能,本研究基于千人基因组计划中105个中国南方汉族个体的全基因组测序数据,构建了迄今为止最全面的MH数据集。结果表明,人类基因组中350 bp范围之内的MH位点数量共计9,490,075个,且微单倍型分布密度对染色体变异水平具有提示作用。从多种碱基跨度范围对MH的多态性分析表明,其多态性潜能可达到或者超过常用短串联重复序列位点的水平。此外,本文归纳总结了MH组装灵活等特点,并提出了构建微单倍型数据库的方案。

基于全基因组数据的AI-SNPs筛选及大陆次级区域内群体遗传结构差异研究

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。

“条块并举”发包制下的基层治理——以T区乡镇政府的精准扶贫工作为例

【问题】有关中国基层政府治理实践的已有研究提出了行政发包制(适用于块块维度)和“控制权”理论(适用于条条维度)两种视角,但实践中的基层政府会同时承接来自上级政府和各个部门的发包。近年来,中央启动的一系列改革举措改变了既有发包制的运行。那么,如何概括变化之后的基层政府治理实践呢?【方法】以T区所辖乡镇的精准扶贫工作为个案,在实地调查和深入访谈的基础上,详细呈现了当下基层政府治理的新特征。【发现】中央层面近年来发起的一系列改革举措从三个维度改变了发包制的运行,它们包括行政权限的分配、内部控制和检查验收机制的运行,以及激励机制的设置;这就导致了既有理论模型与现实的偏离。【结论】论文提出了一个新的“条块并举”式发包制的分析框架。这一框架可以很好地概括近年来基层政府治理实践的新特征,并有助于我们理解精准扶贫相关实践中的矛盾现象。

Collection System of Soil Moisture Information Based on ZigBee and GPRS

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.

A virtual reality based surgical skills training simulator for catheter ablation with real-time and robust interaction

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.

Numerical simulation of carbon arc discharge for graphene synthesis without catalyst

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.

SPREADING SPEED IN THE FISHER-KPP EQUATION WITH NONLOCAL DELAY

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.

Accumulative effects of microwave radiation on cardiac injury in rats

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.

Preliminary Study on Water Demand Law of 1-0 Rooted Cuttings of Populus szechuanica

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.