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Prediction of the Biaxial Failure Strength of Composite Laminates with Unit Cell Analytic Model
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作者 赵琳 ZHANG Boming QING Xinlin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第5期923-927,共5页
A new method to predict the ultimate strength of fiber reinforced composites under arbitrary load condition is introduced. The micromechanics strength theory is used to perform the final failure prediction of composit... A new method to predict the ultimate strength of fiber reinforced composites under arbitrary load condition is introduced. The micromechanics strength theory is used to perform the final failure prediction of composite laminates. The theory is based on unit cell analytic model which can provide the ply composite material properties by only using the constituent fiber and matrix properties and the laminate geometric parameters without knowing any experimental information of the laminates. To show that this method is suitable for predicting the strength of composite laminates, the micromechanics strength theory is ranked by comparing it with all the micro-level and the best two macro-level theories chosen from the World Wide Failure Exercise. The results show that this method can be used for predicting strength of any composite laminates and provide a direct reference for composite optimum design. 展开更多
关键词 COMPOSITES STRENGTH failure criteria unit cell analytic model
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Unit Cell Modelling of Auxetic Structure
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作者 Sydney Pothier Reem Roufail Margaret Malton 《Journal of Minerals and Materials Characterization and Engineering》 CAS 2022年第4期360-369,共10页
Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading and vice versa under compression loading. Many fabricated designs for au... Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading and vice versa under compression loading. Many fabricated designs for auxetic materials exist such as re-entrant hexagonal, chiral, and arrowhead geometries. This paper studies the unit cell of the re-entrant hexagonal geometry to understand how changing the internal angle and fillet radius of the structure affects the Poisson’s ratio. The material chosen for this study is acrylonitrile butadiene styrene (ABS) due to its availability and frequent use in additive manufacturing. The study was based on finite element analysis. It is observed that the direction of load applied to the unit cell affects the unit cell strain, Poisson’s ratio, and maximum load capacity before failure responses. It is noticed that the re-entrant cell starts by showing a standard non-auxetic behavior until it reaches a specific axial strain value. A quadratic correlation is identified between axial and transverse strain. Designing an auxetic structure starts with understanding the behavior of a unit cell structure. The auxetic structure design is a complex process that requires a compromise between auxetic property to be achieved and load capacity via avoiding stress concentration zones. 展开更多
关键词 Auxetic Material Negative Poisson’s Ratio Re-Entrant Hexagon Finite Element Analysis unit cell Design
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THE PRINCIPAL CONSTRUCTIVE PROCESS OF UNIT CELL IN Bi-BASED SUPERCONDUCTORS
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作者 Gao Xlaohui Gao De +1 位作者 Gao Yang Jiang Shufen(Department of Chemistry, Central South University of Technology, Changsha, 410083, China ) 《Journal of Central South University》 SCIE EI CAS 1995年第2期1-7,共7页
In this paper, 2201 and 2212 phases as the corresponding precursor of forming 2212 and 2223 phases are discussed,and the constructive process of unit cell of 2201 phase is ascertained by XRD and chemical kinetics me... In this paper, 2201 and 2212 phases as the corresponding precursor of forming 2212 and 2223 phases are discussed,and the constructive process of unit cell of 2201 phase is ascertained by XRD and chemical kinetics method. Subsequently, the process of 221 展开更多
关键词 Bi-based SUPERCONDUCTING PHASES reactional PROCESS construction of unit cell
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Elastic Predictions of 3D Orthogonal Woven Composites Using Micro/meso-scale Repeated Unit Cell Models
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作者 JIA Xiwen GAO Limin +2 位作者 ZHANG Tian ZHANG Fa WANG Yan 《Journal of Donghua University(English Edition)》 EI CAS 2019年第4期390-398,共9页
This presentation predicts the elastic properties of three-dimensional(3D)orthogonal woven composite(3DOWC)by finite element analysis based on micro/meso repeated unit cell(RUC)models.First,the properties of fiber yar... This presentation predicts the elastic properties of three-dimensional(3D)orthogonal woven composite(3DOWC)by finite element analysis based on micro/meso repeated unit cell(RUC)models.First,the properties of fiber yarn are obtained by analysis on a micro-scale RUC model assuming fibers in a hexagonal distribution pattern in the polymer matrix.Then a full thickness meso-scale RUC model including weft yarns,warp yarns,Z-yarns and pure resin zones is established and full stiffness matrix of the 3DOWC including the in-plane and flexural constants are predicted.For thick 3DOWC with large number of weft,warp layers,an alternative analysis method is proposed in which an inner meso-RUC and a surface meso-RUC are established,respectively.Then the properties of 3DOWC are deduced based on laminate theory and properties of the inner and surface layers.The predicted results by the above two alternative methods are in good experimental agreement. 展开更多
关键词 composite MULTI-SCALE analysis repeated unit cell model FINITE ELEMENT method
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Electronic Band Structure of Graphene Based on the Rectangular 4-Atom Unit Cell
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作者 Akira Suzuki Masashi Tanabe Shigeji Fujita 《Journal of Modern Physics》 2017年第4期607-621,共15页
The Wigner-Seitz unit cell (rhombus) for a honeycomb lattice fails to establish a k-vector in the 2D space, which is required for the Bloch electron dynamics. Phonon motion cannot be discussed in the triangular coordi... The Wigner-Seitz unit cell (rhombus) for a honeycomb lattice fails to establish a k-vector in the 2D space, which is required for the Bloch electron dynamics. Phonon motion cannot be discussed in the triangular coordinates, either. In this paper, we propose a rectangular 4-atom unit cell model, which allows us to discuss the electron and phonon (wave packets) motion in the k-space. The present paper discusses the band structure of graphene based on the rectangular 4-atom unit cell model to establish an appropriate k-vector for the Bloch electron dynamics. To obtain the band energy of a Bloch electron in graphene, we extend the tight-binding calculations for the Wigner-Seitz (2-atom unit cell) model of Reich et al. (Physical Review B, 66, Article ID: 035412 (2002)) to the rectangular 4-atom unit cell model. It is shown that the graphene band structure based on the rectangular 4-atom unit cell model reveals the same band structure of the graphene based on the Wigner-Seitz 2-atom unit cell model;the &pi;-band energy holds a linear dispersion (&epsilon;&minus;k ) relations near the Fermi energy (crossing points of the valence and the conduction bands) in the first Brillouin zone of the rectangular reciprocal lattice. We then confirm the suitability of the proposed rectangular (orthogonal) unit cell model for graphene in order to establish a 2D k-vector responsible for the Bloch electron (wave packet) dynamics in graphene. 展开更多
关键词 GRAPHENE RECTANGULAR 4-Atom unit cell Model PRIMITIVE Orthogonal Basis VECTOR BLOCH Electron (Wave Packet) Dynamics k-Vector Dirac Points Linear Dispersion Relation
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Theoretical aspects of selecting repeated unit cell model in micromechanical analysis using displacement-based finite element method 被引量:2
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作者 Lijun GAO Chengyu WANG +1 位作者 Zhanli LIU Zhuo ZHUANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2017年第4期1417-1426,共10页
Repeated Unit Cell(RUC)is a useful tool in micromechanical analysis of composites using Displacement-based Finite Element(DFE)method,and merely applying Periodic Displacement Boundary Conditions(PDBCs)to RUC is ... Repeated Unit Cell(RUC)is a useful tool in micromechanical analysis of composites using Displacement-based Finite Element(DFE)method,and merely applying Periodic Displacement Boundary Conditions(PDBCs)to RUC is almost a standard practice to conduct such analysis.Two basic questions arising from this practice are whether Periodic Traction Boundary Conditions(PTBCs,also known as traction continuity conditions)are guaranteed and whether the solution is independent of selection of RUCs.This paper presents the theoretical aspects to tackle these questions,which unify the strong form,weak form and DFE method of the micromechanical problem together.Specifically,the solution’s independence of selection of RUCs is dealt with on the strong form side,PTBCs are derived from the weak form as natural boundary conditions,and the validity of merely applying PDBCs in micromechanical Finite Element(FE)analysis is proved by referring to its intrinsic connection to the strong form and weak form.Key points in the theoretical aspects are demonstrated by illustrative examples,and the merits of setting micromechanical FE analysis under the background of a clear theoretical framework are highlighted in the efficient selection of RUCs for Uni Directional(UD)fiber-reinforced composites. 展开更多
关键词 Finite element method Micromechanics of composites Periodic boundary condition Repeated unit cell Theoretical aspect Traction continuity
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Direct evidence of high temperature superconductivity in one-unit-cell FeSe films on SrTiO_3 substrate by transport and magnetization measurements 被引量:2
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作者 邢颖 王健 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第11期15-22,共8页
Zero resistance and Meissner effect are two crucial experimental evidences of superconductivity in determining a new kind of superconductor, which can be detected by transport and diamagnetic measurements. In this pap... Zero resistance and Meissner effect are two crucial experimental evidences of superconductivity in determining a new kind of superconductor, which can be detected by transport and diamagnetic measurements. In this paper, we briefly review the main transport and magnetization results on the one unit cell (1-UC) FeSe films grown on SrTiO3 (STO) substrates from our team in recent years, which identify the high temperature superconductivity in 1-UC FeSe films. 展开更多
关键词 two-dimensional superconductivity one-unit-cell FeSe transport measurement diamagnetic prop-erty
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THE CONFIGURATION OF QUASICRYSTAL UNIT CELL AND DEDUCTION OF QUASILATTICE 被引量:1
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作者 施倪承 闵乐泉 沈步明 《Science China Chemistry》 SCIE EI CAS 1992年第6期735-744,共10页
From the crystal chemistry and icosahedral phase, two kinds of coordinational polyhedron with 8-fold rotational symmetry——hexakaicahedra and bicapped antiprism were possibly suggested and their one- and two-dimensio... From the crystal chemistry and icosahedral phase, two kinds of coordinational polyhedron with 8-fold rotational symmetry——hexakaicahedra and bicapped antiprism were possibly suggested and their one- and two-dimensional quasilattices were deducted. According to the principle of Bravais in conventional crystallography, four kinds of two-dimensional unit cell have been defined in 5, 8, 10, 12-fold rotational symmetry quasicrystal. The authors considered that quasicrystal is a kind of crystal which possesses an incommensurable translational period. This kind of translation is carried out by inflation or deflation symmetry operation. 展开更多
关键词 quasierystal coordinational POLYHEDRON Bravais unit cell incommensurable TRANSLATIONAL period INFLATION or DEFLATION symmetry operation.
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Preparation of patterned boron nanowire films with different widths of unit-cell and their field emission properties
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作者 张永欣 刘飞 +4 位作者 申承民 李军 邓少芝 许宁生 高鸿钧 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第8期407-411,共5页
Large-area patterned films of boron nanowires(BNWs) are fabricated at various densities by chemical vapor deposition(CVD). Different widths of unit-cell of Mo masks are used as templates. The widths of unit-cell o... Large-area patterned films of boron nanowires(BNWs) are fabricated at various densities by chemical vapor deposition(CVD). Different widths of unit-cell of Mo masks are used as templates. The widths of unit-cell of Mo masks are100 μm, 150 μm, and 200 μm, respectively. The distance between unit cells is 50 μm. The BNWs have an average diameter of about 20 nm and lengths of 10 μm–20 μm. High-resolution transmission electron microscopy analysis shows that each nanowire has a β-tetragonal structure with good crystallization. Field emission measurements of the BNW films show that their turn-on electric fields decrease with width of unit-cell increasing. 展开更多
关键词 patterned boron nanowires different width of unit-cell field emission properties
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Application of Solid Oxide Fuel Cell-Auxiliary Power Unit on Different Trucks in Northeast China
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作者 周苏 王士嘉 《Journal of Donghua University(English Edition)》 EI CAS 2015年第4期565-570,共6页
A diesel engine of conventional trucks has a low efficiency under the idling condition,leading to a high cost for heating or cooling in the cab during night. The solution to this problem will have great significance o... A diesel engine of conventional trucks has a low efficiency under the idling condition,leading to a high cost for heating or cooling in the cab during night. The solution to this problem will have great significance on energy conservation and emission reduction. A new auxiliary power unit of solid oxide fuel cell( SOFCAPU) with high efficiency solves this problem perfectly. Heat pump air conditioner is considered as a promising device for the application of SOFC-APU with a high cooling and heating efficiency. To make a quantitative analysis for the application of SOFC-APU,a model is built in Matlab / Simulink. The diesel engine model and SOFC-APU model are fitted based on some experimental data of SOFC-APU and diesel engine during the idling operation. An analysis of the application of SOFC-APU on different trucks in Northeast China is comprehensively made,including efficiency and emission. 展开更多
关键词 diesel engine TRUCK heating and cooling POWER emissions AUXILIARY POWER unit of solid oxide fuel cell(SOFC-APU)
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单一应力下义马原煤热解产物演变规律及动力学模拟
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作者 邓奇根 刘朝思 +1 位作者 姚萌萌 李帅 《煤炭转化》 CAS CSCD 北大核心 2024年第1期19-27,共9页
以义马原煤为研究对象,构造晶胞,在ReaxFF力场中施加5×10^(9)s^(-1)的应变率,模拟1000K,1500K,2000K,2500K,3000K终温下义马原煤热解演化过程,分析单一应力对褐煤热解的作用效果。结果表明:不同模拟终温下,不同方向上的应力是上下... 以义马原煤为研究对象,构造晶胞,在ReaxFF力场中施加5×10^(9)s^(-1)的应变率,模拟1000K,1500K,2000K,2500K,3000K终温下义马原煤热解演化过程,分析单一应力对褐煤热解的作用效果。结果表明:不同模拟终温下,不同方向上的应力是上下波动的,在允许一定误差下,应力范围保持在±70GPa之间,即此应力对褐煤热解的作用受温度的影响较弱。模拟过程中,在26ps~33ps之间分子数出现极小值点而种类数出现极大值点,义马原煤热解模拟起始温度点不变,但缩聚反应的温度区间前移,表明反应前期单一应力作用效果优于温度作用效果,应力促进了整体的反应进程。受缩聚反应的影响,CO,CH_(4),H_(2)O和NH_(3)含量先升后降,符合热解一般规律,说明应力没有改变反应的最终趋势。H_(2)和·H的数量随反应进行持续上升,说明缩聚反应过程中,此应力作用促进焦油裂解生成的·H的数量大于缩聚反应消耗的·H的数量;同时,·H和H_(2)含量升高,促进·SH与·H结合,提高了H_(2)S的产率。 展开更多
关键词 分子模拟 晶胞 应力 ReaxFF力场 热解产物
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晶体结构教学中的基本概念表述与内涵的探讨
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作者 张冬菊 《大学化学》 CAS 2024年第3期18-22,共5页
晶体结构是结构化学课程中的重要教学内容,包含的知识点多、概念抽象、理论性强。本文探讨晶体结构教学中一些基本概念的表述与内涵,包括点阵、晶格、结构基元、晶胞等,以期帮助学生澄清一些模糊不清的认识,引导学生正确理解晶体学理论... 晶体结构是结构化学课程中的重要教学内容,包含的知识点多、概念抽象、理论性强。本文探讨晶体结构教学中一些基本概念的表述与内涵,包括点阵、晶格、结构基元、晶胞等,以期帮助学生澄清一些模糊不清的认识,引导学生正确理解晶体学理论的基础知识和基本概念。 展开更多
关键词 点阵 晶格 结构基元 晶胞
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Hierarchy of mesenchymal stem cells: Comparison of multipotentmesenchymal stromal cells with fibroblast colony forming units 被引量:2
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作者 Irina N. Shipounova Natalia A. Petinati +5 位作者 Alexey E. Bigildeev Natalia V. Sats Nina J. Drize Larisa A. Kuzmina Elena N. Parovichnikova Valery G. Savchenko 《Journal of Biomedical Science and Engineering》 2013年第8期66-73,共8页
The organization of the compartment of mesenchymal stem cells is still obscure. Two types of human stromal precursor cells are known. Both of them are analyzed in in vitro system: mesenchymal multipotent stromal cells... The organization of the compartment of mesenchymal stem cells is still obscure. Two types of human stromal precursor cells are known. Both of them are analyzed in in vitro system: mesenchymal multipotent stromal cells (MMSC) and fibroblast colony forming units (CFU-F). The aim of this study was to compare the main characteristics of MMSC and CFU-F derived from the bone marrow of 24 healthy donors. Growth and differentiation parameters, as well as relative expression levels of different genes were analyzed in MMSC and CFU-F. MMSC were cultivated for 5 passages. CFU-F concentration was determined for each bone marrow sample. The data obtained demonstrated the heterogeneity and hierarchical organization of both studied populations of stromal precursor cells-MMSC and CFU-F. These two types of stromal precursor cells turned to be different in most parameters studied. Altogether MMSC seemed to be more immature cells than CFU-F and took up the higher position in hierarchical tree of mesenchymal stem cells. The rate of differentiation and proliferative potential decreased with the donor’s age in both populations MMSC and CFU-F. 展开更多
关键词 Mesenchymal MULTIPOTENT Stromal cells (MMSC) FIBROBLAST COLONY FORMING unitS (CFU-F) Real-Time Polymerase Chain Reaction Gene Expression Level Aging
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固体氧化物电解槽辅助煤电机组深度调峰技术可行性研究 被引量:1
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作者 王林 刘晓莎 +3 位作者 胡平 李治宽 李昭 张鹏 《热力发电》 CAS CSCD 北大核心 2024年第2期133-141,共9页
常规的煤电机组灵活性改造方案,难以消除频繁快速变负荷对热力系统造成的潜在寿命折损与设备安全风险。为提高煤电机组参与深度调峰的长期安全性与经济性,以某国产超超临界二次再热1000 MW燃煤机组为应用对象,提出了基于氢储能系统的煤... 常规的煤电机组灵活性改造方案,难以消除频繁快速变负荷对热力系统造成的潜在寿命折损与设备安全风险。为提高煤电机组参与深度调峰的长期安全性与经济性,以某国产超超临界二次再热1000 MW燃煤机组为应用对象,提出了基于氢储能系统的煤电机组“健康调峰”技术路线,并论证了调峰煤电制氢的间接碳减排意义。在此基础上,分析比较了不同制氢工艺与煤电厂生产条件的匹配程度,认为固体氧化物电解槽(SOEC)制氢为综合最优方案,据此给出了SOEC耦合煤电调峰的原理性设计方案,最后以年度负荷曲线对新方案进行了财务分析。计算结果表明,示例机组自第6年起每年可获得1.07亿元/年的净利润,每年减少碳排放281.92 t,同时获得设备延寿、降耗减碳等其他收益。相关结论对于指导调峰煤电机组的健康安全运行具有参考意义。 展开更多
关键词 电解制氢 固体氧化物电解槽 煤电机组 可行性 财务分析
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基于氢储能的煤电机组灵活性改造方案研究
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作者 王林 刘晓莎 +2 位作者 胡平 李昭 张鹏 《工业加热》 CAS 2024年第4期63-67,共5页
现有的煤电机组灵活性改造方案,聚焦局部与短期,难以消除频繁快速变负荷对热力系统造成的长期寿命折损与安全风险。为提高煤电机组参与电力市场辅助服务的安全性与经济性,提出建立基于氢储能系统的煤电机组系统级灵活性改造方案。分析... 现有的煤电机组灵活性改造方案,聚焦局部与短期,难以消除频繁快速变负荷对热力系统造成的长期寿命折损与安全风险。为提高煤电机组参与电力市场辅助服务的安全性与经济性,提出建立基于氢储能系统的煤电机组系统级灵活性改造方案。分析了现有制氢路线,认为固体氧化物电解槽路线与煤电机组结合度高,且具有辅助煤电机组削减碳排放、提升经营收益的综合优点。以某国产1000 MW超超临界二次再热燃煤机组为应用对象,提出了氢储能系统与煤电机组的可行性结合方案。相关研究成果对于开发新型系统级的安全、健康经济的煤电灵活性提升改造方案具有参考意义。 展开更多
关键词 氢储能 固体氧化物电解槽 煤电机组 灵活性 安全健康
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骨支架多孔结构设计及其流场特性研究
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作者 邵海天 段明德 +1 位作者 张壮雅 杨子威 《机械设计与制造》 北大核心 2024年第8期217-222,共6页
组织工程骨支架的结构及其内部流场的流体流动性能直接影响着营养物质的渗入和细胞的沉积。基于拓扑优化技术,以胫骨骨折实际受力为载荷设计不同孔隙率和尺度下的骨支架多孔结构单胞模型;运用计算流体动力学(CFD)方法对所得单胞及由其... 组织工程骨支架的结构及其内部流场的流体流动性能直接影响着营养物质的渗入和细胞的沉积。基于拓扑优化技术,以胫骨骨折实际受力为载荷设计不同孔隙率和尺度下的骨支架多孔结构单胞模型;运用计算流体动力学(CFD)方法对所得单胞及由其构建的多孔结构内部流场特性进行数值模拟,分析模型参数对各结构内部流场的流速分布和渗透率等的影响规律。结果表明各孔隙率和尺度下的单胞及多孔结构均具有良好的流场连通性,其中孔隙率是影响结构内流速的主要因素;各结构渗透率随着孔隙率和尺度的增大而增大;孔隙率和尺度较大的结构表现出更好的流体流动性能。研究成果可以为骨支架多孔结构的优化设计及应用提供支撑。 展开更多
关键词 拓扑优化 单胞模型 多孔结构 计算流体动力学 流动性能
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基于肠道菌群平衡分析微生态制剂联合浙贝黄芩汤对急性淋巴细胞白血病大剂量化疗后患者的临床影响
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作者 张雯 宋超 +4 位作者 钟镇阳 呼婷 汪梅花 拓进宝 曹慧琴 《中国药物与临床》 CAS 2024年第18期1157-1162,共6页
目的探讨微生态制剂联合浙贝黄芩汤对急性淋巴细胞白血病(ALL)大剂量化疗后患者粒细胞集落刺激因子受体(G-CSFR)、粒单系集落形成单位(CFU-GM)、肠道菌群及红系爆式集落形成单位(BFU-E)的影响。方法选取延安大学附属医院2019年6月至2022... 目的探讨微生态制剂联合浙贝黄芩汤对急性淋巴细胞白血病(ALL)大剂量化疗后患者粒细胞集落刺激因子受体(G-CSFR)、粒单系集落形成单位(CFU-GM)、肠道菌群及红系爆式集落形成单位(BFU-E)的影响。方法选取延安大学附属医院2019年6月至2022年12月收治的ALL患者130例作为研究对象,根据治疗方法将患者分为A组、B组、C组,3组患者均接受大剂量化疗,化疗结束48 h后A组患者实施常规治疗,B组患者单纯浙贝黄芩汤治疗,C组给予微生态制剂联合浙贝黄芩汤治疗,治疗12 d后,对3组患者G-CSFR、CFU-GM、BFU-E表达情况及血细胞数量进行检测。结果治疗后,C组血红蛋白、白细胞、血小板[(79±6)g/L、(3.8±0.4)×10^(9)/L、(66.4±3.6)×10^(9)/L]与A组[(59±7)g/L、(3.2±0.4)×10^(9)/L、(52.6±2.8)×10^(9)/L]、B组[(61±7)g/L、(3.1±0.3)×10^(9)/L、(52.8±2.6)×10^(9)/L]对比,差异有统计学意义(P<0.05)。C组G-CSFR(5.35±0.16)pg/ml和白细胞介素-11受体(IL-11R)(6.38±0.54)μg/kg水平均高于A组[(2.23±0.13)pg/ml和(1.49±0.24)μg/kg]和B组[(2.31±0.16)pg/ml和(2.31±0.49)μg/kg]差异有统计学意义(P<0.05)。治疗后,C组患者7 d CFU-GM(18.5±6.0)个和14 d BFU-E(83.5±7.5)个高于A组[7 d CFU-GM(9.5±2.0)个和14 d BFU-E(59.5±6.5)个]和B组[7 d CFU-GM(12.0±6.5)个和14 d BFU-E(63.5±5.0)个],差异有统计学意义(P<0.05)。7 d后,C组双歧杆菌(12.56±3.25)lgCFU/g、乳酸杆菌(13.56±2.58)lgCFU/g、肠杆菌(5.12±1.45)lgCFU/g、肠球菌(5.14±0.58)lgCFU/g高于A组[(9.26±1.03)lg CFU/g、(8.65±0.84)lg CFU/g、(8.08±0.64)lgCFU/g、(8.15±0.46)lgCFU/g]和B组[(11.35±1.36)lg CFU/g、(12.43±1.14)lgCFU/g、(6.49±0.55)lgCFU/g、(6.66±0.43)lgCFU/g],差异有统计学意义(P<0.05)。结论微生态制剂联合浙贝黄芩汤治疗可以有效提高ALL大剂量化疗后患者的G-CSFR、CFU-GM、BFU-E水平,可能更好地改善化疗引起的患者骨髓抑制情况,改善肠道菌群,具有临床研究价值。 展开更多
关键词 白血病 淋巴样 受体 粒细胞集落刺激因子 干细胞 粒单系集落形成单位 红系爆式集落形成单位
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GNPs改性环氧3D编织复合材料导热特性研究
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作者 徐焜 侯辰辉 +2 位作者 程云浦 钱小妹 严刚 《南京航空航天大学学报》 CAS CSCD 北大核心 2024年第4期705-711,共7页
石墨烯纳米片(Graphene nanoplatelets,GNPs)改性3D编织复合材料将GNPs与编织物有机融合,有望协同提高材料导热特性。然而,3D编织复合材料内胞和表胞呈现出不同的导热特性,加之GNPs的协同改性作用,增加了材料导热特性研究难度。本文紧扣... 石墨烯纳米片(Graphene nanoplatelets,GNPs)改性3D编织复合材料将GNPs与编织物有机融合,有望协同提高材料导热特性。然而,3D编织复合材料内胞和表胞呈现出不同的导热特性,加之GNPs的协同改性作用,增加了材料导热特性研究难度。本文紧扣GNPs改性3D编织复合材料细观结构特征,以GNPs改性树脂等效热导率表征为基础,基于周期性温度边界条件,构建材料的多胞有限元热物理分析模型,详尽研究了GNPs含量、编织角和纤维体积分数等对各胞元热导率的影响规律。分析表明:随着GNPs含量增加,3D编织复合材料导热特性逐步提升。随着编织角增加,GNPs改性3D编织复合材料横向热导率迅速增加而纵向热导率下降;同时,GNPs改性3D编织复合材料热导率随纤维体积分数增加而提升。上述规律为GNPs改性3D编织复合材料导热性能设计提供了坚实的理论基础。 展开更多
关键词 3D编织 热导率 石墨烯纳米片 胞元分析 有限元建模
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针刺碳/碳编织复合材料的弹性性能
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作者 梅颖猷 孙志军 刘永兵 《东华大学学报(自然科学版)》 CAS 北大核心 2024年第4期83-90,共8页
为研究针刺碳/碳(C/C)编织复合材料的编织结构和针刺密度对整体力学性能的影响,根据针刺C/C编织复合材料的细观结构、组成成分的体积参数和编织角度,提出带有针刺区域和编织结构的平行四边形单胞模型。建立针刺C/C编织复合材料细观结构... 为研究针刺碳/碳(C/C)编织复合材料的编织结构和针刺密度对整体力学性能的影响,根据针刺C/C编织复合材料的细观结构、组成成分的体积参数和编织角度,提出带有针刺区域和编织结构的平行四边形单胞模型。建立针刺C/C编织复合材料细观结构模型,研究编织角度和针刺密度对整体复合材料弹性性能的影响。结果表明:针刺区域与纤维区域的接触处存在应力集中,纤维周围的基体也出现明显的应力集中现象;编织角对针刺C/C编织复合材料的弹性模量的影响较大。采用GB/T33501—2017标准进行复合材料轴向拉伸试验,发现模型预测的弹性模量与试验数据吻合良好,预测结果的误差为2.27%。研究针刺C/C编织复合材料的细观结构可为后续复合材料细观结构的设计和力学性能的探讨提供依据。 展开更多
关键词 复合材料 编织角 针刺密度 弹性性能 单胞模型 应力分析
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基于改进鲸鱼算法优化GRU的PEMFC老化预测
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作者 李浩 李浩 +2 位作者 杨扬 朱文超 谢长君 《中国电机工程学报》 EI CSCD 北大核心 2024年第20期8166-8177,I0021,共13页
为提高质子交换膜燃料电池(protonexchange membranefuelcells,PEMFC)老化预测的可控性和预测精度,提出一种基于改进的鲸鱼优化算法(improvedwhale optimizationalgorithm, IWOA)优化门控循环单元(gated recurrent unit,GRU)神经网络的P... 为提高质子交换膜燃料电池(protonexchange membranefuelcells,PEMFC)老化预测的可控性和预测精度,提出一种基于改进的鲸鱼优化算法(improvedwhale optimizationalgorithm, IWOA)优化门控循环单元(gated recurrent unit,GRU)神经网络的PEMFC电压预测方法。采用IWOA获得GRU的最优超参数组,再利用GRU准确预测PEMFC电压。采用静态、准动态和动态工况下3组老化实验数据集,将提出的方法与反向传播神经网络、极限学习机、循环神经网络、长短期记忆神经网络、GRU和鲸鱼算法优化门控循环单元这6种方法相比较,所提出方法具有最高的老化预测和剩余使用寿命(remainingusefullife,RUL)估计精度。在静态、准动态和动态工况下,训练集占比为50%时,相比于GRU,所提出方法的预测结果的均方根误差分别降低56.99%、35.12%和9.95%。因此,该方法能够实现高精度PEMFC老化趋势和RUL预测。 展开更多
关键词 质子交换膜燃料电池 鲸鱼优化算法 门控循环单元 老化预测 剩余使用寿命
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