检索结果-南通市图书馆

Effect of Nb addition on microstructure and mechanical properties of 25CrNiMoV(DZ2)steel for high-speed railway axles

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2022年第5期29卷 802-809页

作者： jin-wen zhang Yan-guang Cao Cheng-guo zhang Zhao-dong Li wen-xian Wang College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024ShanxiChina Technology Center Taiyuan Iron and Steel(Group)Co.Taiyuan030003ShanxiChina Department of Structural Steels Central Iron and Steel Research InstituteBeijing100081China Locomotive and Car Research Institute China Academy of Railway Sciences Corporation LimitedBeijing100081China

The microstructure,precipitates and properties of 25CrNiMoV(DZ2)steel for high-speed railway axles with different Nb contents were investigated by means of optical microscopy,scanning electron microscopy,electron back-scattering diffraction,transmission electron microscopy and physicochemical phase *** results show that the grain size of the original austenite of the test steels decreases from 20.5 to 14.2 and 10.8μm after adding 0.026 and 0.039 wt.%Nb to a 25CrNiMoV steel,***,the block width of the tempered martensite in the test steels is refined from 1.91 to 1.72 and 1.60µm,***-type precipitates in 25CrNiMoV steel are mainly VC,while(Nb,V)C gradually precipitates when Nb is microalloyed,and the amount of precipitates increases with increasing Nb *** strengthening mechanism analysis,it is found that grain refinement strengthening is the primary way to increase the *** improvement in the yield strength with increasing Nb content is attributed to a significant increase in precipitation strengthening,grain refinement strengthening and dislocation strengthening.

关键词： High-speed railway axle steel Nb microalloying Precipitate Strengthening mechanism

Epidemiology and region-specific risk factors for low Apgar scores in China:a nationwide study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2022年第2期18卷 135-141页

作者： Yi-wen Wang Yan Chen Yan-Hong Ming jin-wen zhang Kun Sun Jun zhang Yong-Jun zhang Department of Neonatology Xinhua HospitalShanghai Jiao Tong University School of Medicine1665 Kongjiang RoadShanghai 200092China Department of Obstetrics and Gynecology Hospital of Obstetrics and GynecologyFudan UniversityShanghaiChina Shanghai Key Laboratory of Embryo Original Diseases The International Peace Maternity&Child Health HospitalShanghai Jiao Tong University School of MedicineShanghaiChina Department of Pediatrics Xinhua HospitalShanghai Jiao Tong University School of MedicineShanghaiChina Ministry of Educaticn-Shanghai Key Laboratory of Children's Env ironmental Health Xinhua HospitalShanghai Jiao Tong University School of MedicineShanghaiChina

Background Neonatal asphyxia is a serious public health *** study aimed to determine the epidemiology and region-specific risk factors for low Apgar scores,an important proxy for neonatal asphyxia,in China from 2015 to *** The China Labor and Delivery Survey was a multicenter cross-sectional study including 96 hospitals distributed in 24(out of 34)*** regression analysis was performed to examine the risk factors for a low Apgar score(<7).Correspondence analyses were performed among neonates with low Apgar scores to explore the relationship between risk factors and geographical *** population attributable risk percentage(PAR%)was calculated for each region-specific risk *** A total of 72,073 live births,including 320 births with low Apgar scores,were used for the analysis,giving a weighted rate of 3.9/1000 live *** was a substantial difference in the incidence of low Apgar scores by geographic region,from 2.3/1000 live births in East China to 10.9/1000 live births in Northeast *** and obstetric factors are the major region-specific risk *** Southwest China,hypertensive disorders in pregnancy were more important contributors,with PAR% being 74.47%;in North and Northwest China,pre-pregnancy underweight was a more significant factor,with PAR% of 62.92%;in East China,infants born between 0:00 *** 7:59 *** a key factor,with PAR% of 80.44%.Conclusion Strategies based on region-specific risk factors should be considered to reduce the burden of low Apgar scores in China.

关键词： Apgar score China Epidemiology Risk factor

Design study of charge-stripping scheme of heavy ion beams for HIAF-BRing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第5期35卷 30-41页

作者： Jun-Jie zhang Zhi-You Xu jin-Quan zhang wen-wen Ge Liang-Ting Sun Huan-Yu Zhao Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

Charge strippers play an essential role in heavy-ion accelerators by stripping the projectile ions to higher charge states to enhance the acceleration efficiency downstream of the *** the high-energy mode of the booster ring(BRing)of the high-intensity heavy-ion accelerator facility,the pre-accelerated ions from the iLinac will be stripped by a carbon foil to higher charge states and then injected into the *** key parameters of the stripper and stripped ions were calculated,and the influence of stripping on the beam quality was *** get high stripping efficiencies,the foil thicknesses and resultant charge state distributions for the typical ions were determined by the code *** equilibrium thickness was obtained for the U beam,while the stripper thicknesses for the Xe and Kr beams were determined based on a compromise between the stripped charge states and the stripping *** energy loss,energy straggling,and emittance growth due to stripping have a non-negligible impact on the transport of the stripped beams and the injection of the ***,these parameters were simulated by *** addition,the foil’s temperature evolution,which greatly affects the foil lifetime,was simulated by *** maximum temperature of the foil bombarded by the U and Xe beams with the nominal parameters will exceed the safe value in terms of the impact of evaporation on the foil’s *** the foil temperature constraint,the highest tolerable beam intensity and the injected ion number into the ring were derived for different beam *** results of this paper will present important reference data for the optimization design and commissioning of the beamline and injection to the BRing for the stripped ions.

关键词： High-intensity heavy-ion accelerator facility Charge stripper Energy spread Thermal analysis Emittance growth Injection turns

Close-packed layer spacing as a practical guideline for structure symmetry manipulation of IV-VI/I-V-VI_(2) thermoelectrics

在线全文

学校读者我要写书评

暂无评论

InfoMat 2024年第2期6卷 99-106页

作者： Tao jin Long Yang Xinyue zhang wen Li Yanzhong Pei Interdisciplinary Materials Research Center School of Materials Science and EngineeringTongji UniversityShanghaithe People's Republic of China

The crystal-structure symmetry in real space can be inherited in the reciprocal space,making high-symmetry materials the top candidates for thermoelectrics due to their potential for significant electronic band degeneracy.A practical indicator that can quantitatively describe structural changes would help facilitate the advanced thermoelectric material *** face-centered cubic structures,the spatial environment of the same crystallographic plane family is isotropic,such that the distances between the close-packed layers can be derived from the atomic distances within the *** by this,the relationship between inter-and intra-layer geometric information can be used to compare crystal structures with their desired cubic *** close-packed layer spacing was found to be a practical guideline of crystal structure symmetry in IV-VI chalcogenides and I-V-VI_(2) ternary semiconductors,both of which are historically important *** continuous structural evolution toward high symmetry can be described by the layer spacing when temperature or/and composition change,which is demonstrated by a series of pristine and alloyed thermoelectric materials in this *** layerspacing-based guideline provides a quantitative pathway for manipulating crystal structures to improve the electrical and thermal properties of thermoelectric materials.

关键词： phase transition structure manipulation thermoelectric materials x-ray diffraction

Total ionizing dose effect modeling method for CMOS digital-integrated circuit

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第2期35卷 32-46页

作者： Bo Liang jin-Hui Liu Xiao-Peng zhang Gang Liu wen-Dan Tan Xin-Dan zhang School of Computer Science and Technology Xidian UniversityXi’an 710071China

Simulating the total ionizing dose(TID)of an electrical system using transistor-level models can be difficult and expensive,particularly for digital-integrated circuits(ICs).In this study,a method for modeling TID effects in complementary metaloxide semiconductor(CMOS)digital ICs based on the input/output buffer information specification(IBIS)was *** digital IC was first divided into three parts based on its internal structure:the input buffer,output buffer,and functional *** of these three parts was separately *** the IBIS model,the transistor V-I characteristic curves of the buffers were processed,and the physical parameters were extracted and modeled using *** the functional area,logic functions were modeled in VHDL according to the data sheet.A golden digital IC model was developed by combining the input buffer,output buffer,and functional area ***,the golden ratio was reconstructed based on TID experimental data,enabling the assessment of TID effects on the threshold voltage,carrier mobility,and time series of the digital *** experiments were conducted using a CMOS non-inverting multiplexer,NC7SZ157,and the results were compared with the simulation results,which showed that the relative errors were less than 2%at each dose *** confirms the practicality and accuracy of the proposed modeling *** TID effect model for digital ICs developed using this modeling technique includes both the logical function of the IC and changes in electrical properties and functional degradation impacted by TID,which has potential applications in the design of radiation-hardening tolerance in digital ICs.

关键词： CMOS digital-integrated circuit Total ionizing dose IBIS model Behavior-physical hybrid model Physical parameters

Applications of single-cell RNA sequencing in spermatogenesis and molecular evolution

在线全文

学校读者我要写书评

暂无评论

Zoological Research 2024年第3期45卷 575-585页

作者： wen-Bo Chen Meng-Fei zhang Fan Yang jin-Lian Hua College of Veterinary Medicine Shaanxi Centre of Stem Cells Engineering&TechnologyNorthwest A&F UniversityYanglingShaanxi 712100China Key Laboratory of Livestock Biology Northwest A&F UniversityYanglingShaanxi 712100China

Spermatogenic cell heterogeneity is determined by the complex process of spermatogenesis ***,effectively revealing the regulatory mechanisms underlying mammalian spermatogenic cell development and differentiation via traditional methods is *** in technology have led to the emergence of many single-cell transcriptome sequencing protocols,which have partially addressed these *** this review,we detail the principles of 10x Genomics technology and summarize the methods for downstream analysis of single-cell transcriptome sequencing ***,we explore the role of single-cell transcriptome sequencing in revealing the heterogeneity of testicular ecological niche cells,delineating the establishment and disruption of testicular immune homeostasis during human spermatogenesis,investigating abnormal spermatogenesis in humans,and,ultimately,elucidating the molecular evolution of mammalian spermatogenesis.

关键词： Single-cell RNA sequencing(scRNA-seq) Spermatogenesis Molecular evolution Sertoli cell

Formal Modeling and Verification of Carrier-borne Aircraft Ammunition Support Operation Scheduling

在线全文

学校读者我要写书评

暂无评论

Ruan Jian Xue Bao/Journal of Software 2024年第9期35卷

作者： jin, Zhao jin, Lu zhang, Bo-wen Wu, Qing-Shun Feng, Shuo Li, Guan-Feng Xu, Ming-Liang School of Computer and Artificial Intelligence Zhengzhou University Zhengzhou 450001 China Engineering Research Center of Intelligent Swarm Systems Ministry of Education Zhengzhou 450001 China National Supercomputing Center in Zhengzhou Zhengzhou 450001 China Beijing Institute of Astronautical Systems Engineering Beijing 100076 China The 713 Research Institute of China Shipbuilding Industry Corporation Zhengzhou 450015 China

As an efficient scheduling method, the intelligent planning of ammunition support operation of carrier-borne air craft is an important way to boost the development of advanced technology of aircraft carrier engineering. Ensuring the correctness of operation planning schemes under the high safety-critical attribute has gradually become the key technical bottleneck restricting the security of their practical application deployments. Aiming at the challenges posed by the difficulties in modeling ammunition support systems, describing operation execution behavior, and realizing formal verification tools, this study proposes a behavior model for ammunition support systems based on the separation logic idea, where the theorem prover Coq is employed to conduct formal verification on the operation planning scheme. First, a serialized two-tier resource heap model that conforms to the characteristics of ammunition support operation is proposed. Subsequently, a set of modeling language and operational semantics are constructed based on this model to describe job execution behavior. Finally, a proof assistant tool is implemented in Coq. The usability and engineering practicability of the tool are verified by interactive demonstrations of several typical ammunition support operation planning schemes. © 2024 Chinese Academy of Sciences. All rights reserved.

关键词： Aircraft

Multidimensional hollow SiO_(2)/C nanofibers modified by magnetic nanocrystals for electromagnetic energy conversion and lithium battery storage

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第8期17卷 7301-7314页

作者： Chen Han Qi Zheng Juncheng jin Jiajia zhang wen-Qiang Cao Kun Xiang Min zhang Mao-Sheng Cao Anhui Provincial Laboratory of Biomimetic Sensor and Detecting Technology College of Materials and Chemical EngineeringWest Anhui UniversityLu’an 237012China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Department of Physics Beijing Technology and Business UniversityBeijing 100048China

Multifunctional materials are powerful tools to support the advancement of energy conversion *** with prominent electromagnetic and electrochemical properties can realize the conversion of electromagnetic energy and solve the subsequent storage ***,an electrospinning-thermal reduction method is employed to construct ultrafine nickel nanoparticle modified porous SiO_(2)/C(Ni-SiO_(2)/C)hollow nanofibers as promising materials for applications in both electromagnetic wave absorption(EMA)and lithium-ion ***,when used as an EMA material,the reflection loss(RL)of Ni-SiO_(2)/C can reach−47.8 dB at 15.8 GHz with a matching thickness of 2.2 *** excellent microwave absorption performance can be attributed to the enhanced conduction loss,polarization relaxation,synergistic magnetic loss,and preferred impedance matching,which result from multi-component magnetic/dielectric synergy and the unique interconnected multidimensional hollow ***,the electronic conductivity and electrochemical activity of the samples are significantly enhanced due to the uniform distribution of ultrafine Ni nanoparticles in the amorphous SiO_(2)/C ***,the hierarchical hollow porous structure provides sufficient free space for volume change during lithiation/delithiation ***,the Ni-SiO_(2)/C nanocomposite exhibits a high reversible capacity of 917.6 mAh·g^(−1)at 0.1 A·g^(−1).At a high current density of 2 A·g^(−1),a capacity of 563.9 mAh·g^(−1)can be maintained after 300 *** energy conversion-storage device is designed to store waste electromagnetic energy in the form of useful electrical *** work inspires the development of high-performance bifunctional materials.

关键词： Ni-SiO_(2)/C nanofiber electromagnetic absorption lithium-ion storage electrospinning multidimensional structure

Availability and Affordability of Therapeutic Monoclonal Antibodies After the New Medical Reform in Hubei Province,China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Medical Science 2022年第6期42卷 1325-1333页

作者： Yu-feng DING jin-wen zhang Mei-jun XIA Guang-jie WU Wei-jie LI Da FENG Shi-wei GONG Department of Pharmacy Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China Department of Pharmacy Business and Administration School of PharmacyTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China

Objective In 2017,China launched a new round of medical reform(NMR)to address the inaccessibility of high-priced drugs for patients with serious *** study explored the impact of the NMR on the accessibility and affordability of high-priced monoclonal antibodies(mAbs),and the effective promotion policies after the *** We used a standard method developed by the World Health Organization to conduct two surveys on the availability of mAbs and their prices before and after the NMR in the public hospitals in Hubei province,*** interviewing hospital pharmacy experts,we identified the potential value of the current NMR in improving the access to therapeutic *** The average availability of 13 mAbs increased by 8.1%in the surveyed hospitals of Hubei province after the *** median unit price of 10 mAbs dropped by 34.3%.The average affordability of a treatment cycle of 10 mAbs dropped from 680 days to 298 days of the disposable daily income for a middle-income resident(56.2%reduction).The drug price negotiation of medical insurance inclusion and the promotion of consistent evaluation of generic and original drugs could effectively promote the accessibility of ***,the zero markup of drug pricing and the limit on the proportion of drug revenues in public hospitals showed certain negative effects on the availability of *** Not all current NMR policies play a positive role in promoting the accessibility of *** further improve the accessibility of mAbs in the future in China,it is therefore critical to increase the investment in independent research and development of high-quality mAbs,establish localized guidelines for the rational use of mAbs in clinical practice,and have a cost-sharing mechanism for high-priced drugs with multiple stakeholders.

关键词： availability affordability monoclonal antibody new medical reform Hubei province China