Graphene-loaded nickel−vanadium bimetal oxides as hydrogen pumps to boost solid-state hydrogen storage kinetic performance of magnesium hydride

To modify the thermodynamics and kinetic performance of magnesium hydride(MgH_(2))for solid-state hydrogen storage,Ni_(3)V_(2)O_(8)-rGO(rGO represents reduced graphene oxide)and Ni_(3)V_(2)O_(8)nanocomposites were prepared by hydrothermal and subsequent heat treatment.The beginning hydrogen desorption temperature of 7 wt.%Ni_(3)V_(2)O_(8)-rGO modified MgH_(2)was reduced to 208℃,while the additive-free MgH_(2)and 7 wt.%Ni_(3)V_(2)O_(8)doped MgH_(2)appeared to discharge hydrogen at 340 and 226℃,respectively.A charging capacity of about 4.7 wt.%H_(2)for MgH_(2)+7 wt.%Ni_(3)V_(2)O_(8)-rGO was achieved at 125℃ in 10 min,while the dehydrogenated MgH_(2)took 60 min to absorb only 4.6 wt.%H_(2)at 215℃.The microstructure analysis confirmed that the in-situ generated Mg_(2)Ni/Mg_(2)N_(i)H_(4) and metallic V contributed significantly to the enhanced performance of MgH_(2).In addition,the presence of rGO in the MgH_(2)+7 wt.%Ni_(3)V_(2)O_(8)-rGO composite reduced particle aggregation tendency of Mg/MgH_(2),leading to improving the cyclic stability of MgH_(2)during 20 cycles.

基于飞参数据的飞行科目识别研究

对于飞行训练中真实飞行数据存在波动的特点,提出一种基于飞机飞行训练数据的飞行科目识别方法。首先对飞行训练数据进行分析,制定飞行动作状态分割机制;其次在分割后的飞行训练数据子序列中采用随机森林识别方法,通过状态分割机制与随机森林模型进行结合,确定子序列的飞行动作;最后对飞行动作序列采用支持向量机识别方法,从飞行数据中提取飞行训练科目片段。通过对飞行训练数据进行验证,可实现飞行训练科目的有效识别。

加强油库和加油站灭火器使用和管理的措施

针对石油库和加油站灭火器使用和管理存在的问题,提出了相应措施:一是必须加强新配置灭火器的验收,购置合格灭火器,做到相关质量信息齐全,同时注意检查灭火器外观;二是必须精通相关标准和规范,有效配置灭火器,做到配置数量达标,设置位置合理,配备类型适用;三是必须落实有关规定,按照标准维修或报废灭火器,开展制度化的灭火器检查维护工作,充分发挥好灭火器扑灭初起火灾的重要作用。

岳西黑猪与北京黑猪和巴克夏猪的杂交效果分析

岳西黑猪为安徽省岳西县独有的地方猪品种。文章通过繁殖、胴体、肉质性能的测定和比较分析,综合评价北京黑猪和巴克夏猪与岳西黑猪的杂交效果,筛选可推广的杂交组合模式,为岳西黑猪的杂交利用奠定基础,旨在更好地促进岳西黑猪产业化开发。

Development and validation of a questionnaire-based risk scoring system to identify individuals at high risk for gastric cancer in Chinese populations

Objective:This study aimed to develop and validate a risk scoring system to identify high-risk individuals carrying malignant lesions in stomach for tailored gastric cancer screening.Methods:A gastric cancer risk scoring system(GC-RSS)was developed based on questionnaire-based predictors for gastric cancer derived from systematic literature review.To assess the capability of this system for discrimination,risk scores for 8,214 and 7,235 outpatient subjects accepting endoscopic examination in two endoscopy centers,and 32,630 participants in a community-based cohort in China were calculated to plot receiver operating characteristic curves and generate area under the curve(AUC).To evaluate the performance of GC-RSS,the screening proportion,sensitivity and detection rate ratio compared to universal screening were used under different risk score cutoff values.Results:GC-RSS comprised nine predictors including advanced age,male gender,low body mass index(<18.5 kg/m^(2)),family history of gastric cancer,cigarette smoking,consumption of alcohol,preference for salty food,irregularity of meals and consumption of preserved food.This tool performed well in determining the risk of malignant gastric lesions with AUCs of 0.763,0.706 and 0.696 in three validation sets.When subjects with risk scores≥5 were evaluated with endoscopy,nearly 50%of these endoscopies could be saved with a detection rate of over 1.5 times achieved.When the cutoff was set at 8,only about 10%of subjects with the highest risk would be offered endoscopy,and detection rates for gastric cancer could be increased 2-4 fold compared to universal screening.Conclusions:An effective questionnaire-based GC-RSS was developed and validated.This tool may play an important role in establishing a tailored screening strategy for gastric cancer in China.

Real-Time Liquid Evaporation Rate Measurement Based on a Microchip Laser Feedback Interferometer

We present a novel scheme to realize the direct real-time measurement of liquid evaporation rate and nanometer order liquid level monitoring.It is based on the phase measurement technology of Nd:YAG microchip laser frequency-shifted feedback,which not only has a high resolution and precision but also ultrahigh sensitivity.The evaporation rates of four different transparent liquids and hot water are measured.Experimental results indicate the ease and convenience of measuring and present promising application prospects in non-cooperative target measurement.

河南省罗山县石山口生态农业园规划设计

探讨了城市近郊生态农业园规划设计,指出生态农业园的建设应回归生态优先、农业生产的本性,适度融入观光、游览、餐饮、体验等项目,使园区发展根植于地域特色,推动生态效益、经济效益、社会效益的发展。

Exceptional catalytic effect of novel rGO-supported Ni-Nb nanocomposite on the hydrogen storage properties of MgH_(2)

The design of an excellent active catalyst to improve the sluggish kinetic and thermodynamic properties of magnesium hydride(MgH_(2))remains a great challenge to achieve its practical application.In this study,a novel Ni-Nb/rGO nanocomposite catalyst was successfully prepared by one-spot hydrothermal and sub-sequent calcination methods.The novel Ni-Nb/rGO nanocomposite exhibits an exceptional catalytic effect on improving MgH_(2) sorption properties.Specifically,the onset desorption temperature of MgH_(2)+10 wt%Ni-Nb/rGO composite is reduced to 198℃,much lower than that of undoped MgH_(2)(330℃).In-terestingly,the composite can release 5.0,5.9,and 6.0 wt%H_(2) within 10 min at 245,260,and 275℃,respectively.Furthermore,the dehydrogenated MgH_(2)+10 wt%Ni-Nb/rGO composite starts to absorb hydrogen even at room temperature with approximate 2.75 wt%H_(2) uptake at 75℃under 3 MPa H_(2) pressure within 30 min and exhibits excellent stability by maintaining 6.0 wt%hydrogen content after 20 cycles at 300℃.Chou’s model suggests that the de/hydrogenation kinetics of Ni-Nb/rGO-modified MgH_(2) switches from surface penetration model to diffusion model at lower temperatures.Additionally,the ac-tivation energies(E a)for the de/hydrogenation of MgH_(2)+10 wt%Ni-Nb/rGO are reduced to 57.8 kJ/mol and 33.9 kJ/mol,which are significantly lower than those of undoped MgH_(2).The work demonstrates that the addition of a novel ternary Ni-Nb/rGO catalyst is an effective strategy to not only boost the sorption kinetics of MgH_(2) but also maintain its cycling property.

Crystalline Boron-Centered Analogues of Müller's Hydrocarbon

Müller's hydrocarbon is a well-known open-shell singlet diradicaloid,yet its structural determination and redox property remain elusive due to its extremely high reactivity.Herein,we report the successful synthesis and full characterizations of the first neutral boron-centered analogue(4)of Müller's hydrocarbon,along with the first dianionic boron-centered analogue(5^(2−))featuring three isolable redox states.In the presence of two equivalents of N-heterocyclic carbene(NHC),reduction of 4,4”-bis(triisopropylphenylbromoboryl)terphenyl 3 with potassium graphite afforded NHC-stabilized boryl diradicaloid 4 with a near-pure diradical character(y0=0.93).Stepwise reductions of 4,4”-bis(dimesitylboryl)terphenyl 5 in THF yielded the isolable monoradical anion 5·−and diradical dianion 5^(2−),respectively,accompanied by a decreasing aromaticity within the conjugated spacer.Experimental studies and theoretical analyses revealed that both 4 and 5^(2−)exhibit large spin distributions at boron atoms,open-shell singlet ground states,and small singlet-triplet energy gaps.

Standardized Operational Protocol for Human Brain Banking in China

With the progress of society, there is an increasing need to tackle disorders of the central nervous system. Human brain tissue, unlike animal tissues, is an irreplaceable resource for the study of neurological diseases (1)Aimed at scientific research and education, the roles of human brain tissue repositories are to acquire brain tissue from donors, prepare, process, and preserve collected samples,provide tissue to specific eligible facilities, and determine the characteristics of each tissue sample.

Molecular mechanisms of exercise contributing to tissue regeneration

Physical activity has been known as an essential element to promote human health for centuries.Thus,exercise intervention is encouraged to battle against sedentary lifestyle.Recent rapid advances in molecular biotechnology have demonstrated that both endurance and resistance exercise training,two traditional types of exercise,trigger a series of physiological responses,unraveling the mechanisms of exercise regulating on the human body.Therefore,exercise has been expected as a candidate approach of alleviating a wide range of diseases,such as metabolic diseases,neurodegenerative disorders,tumors,and cardiovascular diseases.In particular,the capacity of exercise to promote tissue regeneration has attracted the attention of many researchers in recent decades.Since most adult human organs have a weak regenerative capacity,it is currently a key challenge in regenerative medicine to improve the efficiency of tissue regeneration.As research progresses,exercise-induced tissue regeneration seems to provide a novel approach for fighting against injury or senescence,establishing strong theoretical basis for more and more“exercise mimetics.”These drugs are acting as the pharmaceutical alternatives of those individuals who cannot experience the benefits of exercise.Here,we comprehensively provide a description of the benefits of exercise on tissue regeneration in diverse organs,mainly focusing on musculoskeletal system,cardiovascular system,and nervous system.We also discuss the underlying molecular mechanisms associated with the regenerative effects of exercise and emerging therapeutic exercise mimetics for regeneration,as well as the associated opportunities and challenges.We aim to describe an integrated perspective on the current advances of distinct physiological mechanisms associated with exercise-induced tissue regeneration on various organs and facilitate the development of drugs that mimics the benefits of exercise.

Theoretical model of lithium iron phosphate power battery under high-rate discharging for electromagnetic launch

Due to the large error of the traditional battery theoretical model during large-rate discharge for electromagnetic launch,the Shepherd derivative model considering the factors of the pulse cycle condition,temperature,and life is proposed by the Naval University of Engineering.The discharge rate of traditional lithium-ion batteries does not exceed 10C,while that for electromagnetic launch reaches 60C.The continuous pulse cycle condition of ultra-large discharging rate causes many unique electrochemical reactions inside the cells.The traditional model cannot accurately describe the discharge characteristics of the battery.The accurate battery theoretical model is an important basis for system efficiency calculation,precise discharge control,and remaining capacity prediction.To this purpose,an experimental platform for electromagnetic launch is built,and discharge characteristics of the battery under different rate,temperature,and life decay are measured.Through the experimental test and analysis,the reason that the traditional model cannot accurately characterize the large-rate discharge process is analyzed.And a novel battery theoretical model is designed with the help of genetic algorithm,which is integrated with the electromagnetic launch topology.Numerical simulation is compared with the experimental results,which verifies the modeling accuracy for the large-rate discharge.On this basis,a variety of discharge conditions are applied to test the applicability of the model,resulting in better results.Finally,with the continuous cycle-pulse condition in the electromagnetic launch system,the stability and accuracy of the model are confirmed.