检索结果-南通市图书馆

A Novel Fractional Plastic Damage Model for Quasi-brittle Materials

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2021年第5期34卷 706-717页

作者： Peng-Fei Qu Qi-zhi zhu Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China College of Civil and Transportation Engineering Hohai UniversityNanjing210098China

In this work,a novel constitutive model is developed within the framework of fractional plasticity to delineate the coupling between inelastic deformation and damage of quasi-brittle *** with the common challenge of determining plastic flow direction,we resort herein to the Riemann–Liouville definition of fractional derivatives,instead of introducing an additional plastic *** pre-peak hardening behavior is described using an exponential function,while the post-peak softening response is viewed as the consequence of material *** describing damage evolution,a damage criterion is constructed in terms of plastic volume dilation related to micro-crack *** is conducive to supply a new insight for describing the complex influence of the non-orthogonality of plastic flow on damage *** numerical applications,a semi-implicit return mapping algorithm is *** predictive performance of the model is evaluated by comparing numerical simulations with experimental data under various loading paths.

关键词： Quasi-brittle materials Fractional plasticity Damage Dilatancy Numerical algorithm

An ontological metamodeling framework for semantic simulation model engineering

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2020年第3期31卷 527-538页

作者： LEI Yonglin zhu zhi LI Qun School of Systems Engineering National University of Defense TechnologyChangsha 410073China

Recently,the ontological metamodel plays an increasingly important role to specify systems in two forms:ontology and *** is a descriptive model representing reality by a set of concepts,their interrelations,and *** the other hand,metamodel is a more classical,but more powerful model in which concepts and relationships are represented in a prescriptive *** study firstly clarifies the difference between the two approaches,then explains their advantages and limitations,and attempts to explore a general ontological metamodeling framework by integrating each characteristic,in order to implement semantic simulation model *** a proof of concept,this paper takes the combat effectiveness simulation systems as a motivating case,uses the proposed framework to define a set of ontological composable modeling frameworks,and presents an underwater targets search scenario for running simulations and analyzing ***,this paper expects that this framework will be generally used in other fields.

关键词： ontology metamodeling semantic composability model-driven engineering(MDE)

An optimized sequential extraction scheme for molybdenum association in environmental samples

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2016年第2期35卷 111-119页

作者： liang liang Jian-Ming zhu State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081 People's Republic of China State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083China University of Chinese Academy of Sciences Beijing 100049People's Republic of China

By comparing three sequential extraction pro- cedures, a new optimized extraction scheme for the molyb- denum association in environmental samples was proposed. Five operational steps were described as exchangeable （KH2PO4 ＋ K2HPO4： including water-soluble）, associated with organic matter （NaOH）, Fe-Mn oxides and/or carbonates （HC1）, sulfides （H2O2） and residue （HNO3 ＋ HF ＋ H2O2）. An optimized extraction scheme was com- pared with Tessier＇s procedure and the Commission of European Communities Bureau of Reference （BCR） was applied to black shales. Results showed Tessier＇s procedure gave the lowest concentration values for exchangeable molybdenum and the highest values for the residual molybdenum, which could not present the efficiency of the extraction reagents. BCR＇s procedure showed the highest values in oxidizable molybdenum and presented four fractions of molybdenum, which did not demonstrate the fractions of molybdenum in the black shales in detail. The optimized extraction scheme demonstrated a certain improvement on extraction efficiency over Tessier＇s proce- dure for the lowest residual molybdenum, and revealed morefeatured fraction information of molybdenum in black shales than BCR＇ s. Therefore, after a comparison with other two extraction procedures, the optimized extraction scheme proved suitable for the molybdenum in black shales and it also showed an accurate determination of the molybdenum in the fractions and source of bioavailable Mo.

关键词： Molybdenum Sequential extractionprocedure Black shales

A Filter Method for Nonlinear Semidefinite Programming with Global Convergence

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2014年第10期30卷 1810-1826页

作者： zhi Bin zhu Hua Li zhu School of Mathematics and Computing Science Guilin University of Electronic Technology

In this study, a new filter algorithm is presented for solving the nonlinear semidefinite programming. This algorithm is inspired by the classical sequential quadratic programming method. Unlike the traditional filter methods, the sufficient descent is ensured by changing the step size instead of the trust region radius. Under some suitable conditions, the global convergence is obtained. In the end, some numerical experiments are given to show that the algorithm is effective.

关键词： Cone programming nonlinear semidefinite programming filter method step size globalconvergence

Spatial transcriptomics combined with single-nucleus RNA sequencing reveals glial cell heterogeneity in the human spinal cord

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第11期20卷 3302-3316页

作者： Yali Chen Yiyong Wei Jin Liu Tao zhu Cheng Zhou Donghang Zhang Department of Anesthesiology West China HospitalSichuan UniversityChengduSichuan ProvinceChina Laboratory of Anesthesia and Critical Care Medicine National-Local Joint Engineering Research Center of Translational Medicine of AnesthesiologyWest China HospitalSichuan UniversityChengduSichuan ProvinceChina Department of Anesthesiology Longgang District Maternity&Child Healthcare Hospital of Shenzhen City(Longgang Maternity and Child Institute of Shantou University Medical College)ShenzhenGuangdong ProvinceChina Department of Anesthesiology Affiliated Hospital of Zunyi Medical UniversityZunyiGuizhou ProvinceChina

Glial cells play crucial roles in regulating physiological and pathological functions,including sensation,the response to infection and acute injury,and chronic neurodegenerative *** cells include astrocytes,microglia,and oligodendrocytes in the central nervous system,and satellite glial cells and Schwann cells in the peripheral nervous *** the greater understanding of glial cell types and functional heterogeneity achieved through single-cell and single-nucleus RNA sequencing in animal models,few studies have investigated the transcriptomic profiles of glial cells in the human spinal ***,we used high-throughput single-nucleus RNA sequencing and spatial transcriptomics to map the cellular and molecular heterogeneity of astrocytes,microglia,and oligodendrocytes in the human spinal *** explore the conservation and divergence across species,we compared these findings with those from *** the human spinal cord,astrocytes,microglia,and oligodendrocytes were each divided into six distinct transcriptomic *** the mouse spinal cord,astrocytes,microglia,and oligodendrocytes were divided into five,four,and five distinct transcriptomic subclusters,*** comparative results revealed substantial heterogeneity in all glial cell types between humans and ***,we detected sex differences in gene expression in human spinal cord glial ***,in all astrocyte subtypes,the levels of NEAT1 and CHI3L1 were higher in males than in females,whereas the levels of CST3 were lower in males than in *** all microglial subtypes,all differentially expressed genes were located on the sex *** addition to sex-specific gene differences,the levels of MT-ND4,MT2A,MT-ATP6,MT-CO3,MT-ND2,MT-ND3,and MT-CO_(2) in all spinal cord oligodendrocyte subtypes were higher in females than in ***,the present dataset extensively characterizes glial cell heterogeneity and offers a valuable resource for explo

关键词： astrocyte glial cell human microglia oligodendrocyte sex differentiation single-nucleus RNA sequencing spatial transcriptomics species variation spinal cord

Gel-state polybenzimidazole proton exchange membranes with flexible alkyl sulfonic acid side chains for a wider operating temperature range(25–240 ℃)

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2023年第10期85卷 91-101,I0005页

作者： Taizhong zhu Danyi zhu Jiazhen liang liang Zhang Fei Huang Lixin Xue Center for Membrane Separation and Water Science&Technology College of Chemical EngineeringZhejiang University of TechnologyHangzhou 310014ZhejiangChina College of Chemistry and Materials Engineering Wenzhou UniversityWenzhou 325035ZhejiangChina Received 18 April 2023Revised 30 May 2023Accepted 31

High-temperature proton exchange membrane fuel cells(HT-PEMFC) possess distinct technical advantages of high output power, simplified water/heat management, increased tolerance to fuel impurities and diverse fuel sources, within the temperature range of 120–200 ℃. However, for practical automobile applications, it was crucial to broaden their low-temperature operating window and enable cold start-up capability. Herein, gel-state phosphoric acid(PA) doped sulfonated polybenzimidazole(PBI) proton exchange membranes(PEMs) were designed and synthesized via PPA sol-gel process and in-situ sultone ring-opening reactions with various proton transport pathways based on absorbed PA, flexible alkyl chain connected sulfonic acid groups and imidazole sites. The effects of flexible alkyl sulfonic acid side chain length and content on PA doping level, proton conductivity, and membrane stability under different temperature and relative humidity(RH) were thoroughly investigated. The prepared gel-state membranes contained a self-assembled lamellar and porous structure that facilitated the absorption of a large amount of PA with rapid proton transporting mechanisms. At room temperature, the optimized membrane exhibited a proton conductivity of 0.069 S cm^(-1), which was further increased to 0.162 and 0.358 S cm^(-1)at 80 and 200 ℃, respectively, without additional humidification. The most significant contribution of this work was demonstrating the feasibility of gel-state sulfonated PBI membranes in expanding HT-PEMFC application opportunities over a wider operating range of 25 to 240 ℃.

关键词： Wide temperature range Proton exchange membrane Fuel cell Gel-state Polybenzimidazole

A new digital pulse processing method for 2πa and 2πb emitter measurement

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2016年第6期27卷 137-143页

作者： Zheng Tu Ke-zhu Song Ming Zhang zhi-Jie Yang zhi-Guo Ding Hong-Wei Yu Jun-Cheng liang Hao-Ran Liu State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China National Institute of Metrology 18 North Third Ring EastRd.Beijing 100029China

Digital pulse processing has developed rapidly during recent ***,it has been widely applied in many *** this study,we introduce a digital pulse processing method for 2πa and 2πb emitter *** digital pulse processing method for 2πa and 2πb emitter measurement is comprised of a field-programmable gate-array-based acquisition card and a pulse-height analysis *** established two channels(one for the a emitter and one for the b emitter) on an acquisition board using an analog-to-digital converter with a 16-bit resolution at a speed of 100 million samples per *** this study,we used captured and stored data to analyze emission rate counts and *** method we established takes into account noise cancelation,dead-time correction,background subtraction,and zero-energy *** carefully designed control procedures in order to simplify pulse-width fitting and threshold-level *** transmitted data and commands through a universal serial bus between the acquisition board and the *** results of our tests prove that our method performs well in pulse reconstruction fidelity and amplitude measurement *** with the current standard method for measuring 2πa and 2πb emission rates,our system demonstrates excellent precision in emission rate counting.

关键词：脉冲处理测量性能发射器顺序控制程序 π 数据采集卡测量精度模数转换器

CT引导下经皮穿刺臭氧消融治疗颈椎间盘突出症

在线全文

学校读者我要写书评

暂无评论

四川医学 2010年第5期31卷 680-682页

作者：邓治强朱亮旭李洵余文毅张怀成内江市中医院放射科四川内江641000

目的探讨CT引导下臭氧靶点注射治疗颈椎间盘突出症的价值。方法 48例颈椎间盘突出症患者,术前均经CT或MRI检查证实。在CT引导下行臭氧消融治疗。盘内注入浓度为60-70μg/ml臭氧5-15ml,CT穿刺退针出纤维环至椎间孔附近,注入浓度为40-60μ... 详细信息

目的探讨CT引导下臭氧靶点注射治疗颈椎间盘突出症的价值。方法 48例颈椎间盘突出症患者,术前均经CT或MRI检查证实。在CT引导下行臭氧消融治疗。盘内注入浓度为60-70μg/ml臭氧5-15ml,CT穿刺退针出纤维环至椎间孔附近,注入浓度为40-60μg/ml臭氧0-5ml。结果 48例患者术后6个月随访,按照MacNab疗效评定标准进行评定：优18例（37.5%）,良28例（58.3%）,差2例（4.2%）,优良率95.2%。结论 CT引导下经皮臭氧注射颈椎间盘溶解术是治疗颈椎间盘突出的一种安全有效的微创方法。

关键词：臭氧颈椎间盘突出症 CT引导

基于第一性原理和热力学计算的TiAl-Nb金属间化合物稳定性和相关系研究

在线全文

学校读者我要写书评

暂无评论

原子与分子物理学报 2025年第5期42卷 151-162页

作者：汪文洋徐勇田彬甘信柱王志刚梁永锋林均品山东建筑大学材料科学与工程学院济南250101 北京科技大学新金属材料国家重点实验室北京100083

采用基于广义梯度近似密度泛函理论的第一性原理计算和相图计算方法,研究了TiAl-Nb合金中γ、α_(2)、O_(2)和ωo相的热力学和力学性质以及相转变关系.研究表明,第一性原理计算得到的化合物相的参数是准确的,且分析结果与相图计算结果... 详细信息

采用基于广义梯度近似密度泛函理论的第一性原理计算和相图计算方法,研究了TiAl-Nb合金中γ、α_(2)、O_(2)和ωo相的热力学和力学性质以及相转变关系.研究表明,第一性原理计算得到的化合物相的参数是准确的,且分析结果与相图计算结果相一致.四个化合物相都是能够稳定存在的相.通过热力学和力学性质的分析,发现α_(2)相更容易转变为O_(2)相,并且在一定条件下可以通过相变反应生成ωo相.而γ相更容易转变为ωo相,但无法生成O_(2)相.

关键词： TiAl合金第一性原理相图声子谱及态密度热力学性质