检索结果-南通市图书馆

Aerodynamic Features of High-Speed Maglev Trains with Different Marshaling Lengths Running on a Viaduct under Crosswinds

引用

Computer Modeling in Engineering & Sciences 2024年第7期140卷 975-996页

作者： Zun-Di Huang Zhen-Bin Zhou Ning Chang zheng-wei chen Su-Mei Wang School of Rail Transportation Wuyi UniversityJiangmen529020China National Rail Transit Electrification and Automation Engineering Technology Research Center(Hong Kong Branch) The Hong Kong Polytechnic UniversityHong Kong999077China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong999077China

The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic ***,this paper uses an improved delayed detached eddy simulation(IDDES)method to investigate the aerodynamic features of high-speed maglev trains with different marshaling lengths under *** effects of marshaling lengths(varying from 3-car to 8-car groups)on the train’s aerodynamic performance,surface pressure,and the flow field surrounding the train were investigated using the three-dimensional unsteady compressible Navier-Stokes(N-S)*** results showed that the marshaling lengths had minimal influence on the aerodynamic performance of the head and middle ***,the marshaling lengths are negatively correlated with the time-average side force coefficient(CS)and time-average lift force coefficient(Cl)of the tail *** to the tail car of the 3-car groups,the CS and Cl fell by 27.77%and 18.29%,respectively,for the tail car of the 8-car *** is essential to pay more attention to the operational safety of the head car,as it exhibits the highest time average ***,the mean pressure difference between the two sides of the tail car body increased with the marshaling lengths,and the side force direction on the tail car was opposite to that of the head and middle ***,the turbulent kinetic energy of the wake structure on the windward side quickly decreased as marshaling lengths increased.

关键词： High-speed maglev train marshaling lengths crosswinds aerodynamic features

来源：

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

银含量对快速热冲击下Sn−xAg−0.5Cu焊点显微组织和力学性能的影响

引用

Transactions of Nonferrous Metals Society of China 2024年第6期34卷 1922-1935页

作者：彭晨王善林吴鸣尹立孟陈玉华叶科江陈维政张体明谢吉林南昌航空大学江西省航空构件成形与连接重点实验室南昌330036 江西省智能产业技术创新研究院南昌330200 重庆科技学院冶金与材料工程学院重庆401331

使用高频感应加热设备研究Ag含量对快速热冲击下Sn−xAg−0.5Cu焊点的显微组织和剪切强度的影响。结果表明,Ag含量的增加使焊点表面更致密光滑,减少焊点内部长条状Cu6Sn5金属间化合物(IMC)的产生,从而提高焊点的抗氧化性。Ag能够加快焊点... 详细信息

使用高频感应加热设备研究Ag含量对快速热冲击下Sn−xAg−0.5Cu焊点的显微组织和剪切强度的影响。结果表明,Ag含量的增加使焊点表面更致密光滑,减少焊点内部长条状Cu6Sn5金属间化合物(IMC)的产生,从而提高焊点的抗氧化性。Ag能够加快焊点界面IMC层的生长速度,Cu6Sn5层的生长速度由体扩散和晶界扩散共同决定,Cu3Sn层的生长速度由体扩散和界面反应共同决定。在快速热冲击环境下,焊点的断裂模式从韧性断裂转变为脆性断裂,而高Ag含量使得焊点的断裂模式转变时间更短,降低焊点的抗热疲劳性能。

关键词： Ag含量快速热冲击 Sn−Ag−Cu 焊点生长动力学断裂模式

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

长链非编码RNA LINC00996通过抑制CDKN2A促进胃癌进展

引用

世界华人消化杂志 2024年第4期32卷 302-312页

作者：程国雄刘明陈正伟叶巧萍丽水市人民医院胃肠外科浙江省丽水市323000

背景长链非编码RNA长基因间非蛋白编码RNA 996(long intergenic non-protein coding RNA 996,LINC00996)在多种肿瘤中发挥促癌或抑癌作用,而其在胃癌中的表达和作用尚不清楚.目的探索LINC00996在胃癌组织和细胞系中的表达,并探讨其对胃... 详细信息

背景长链非编码RNA长基因间非蛋白编码RNA 996(long intergenic non-protein coding RNA 996,LINC00996)在多种肿瘤中发挥促癌或抑癌作用,而其在胃癌中的表达和作用尚不清楚.目的探索LINC00996在胃癌组织和细胞系中的表达,并探讨其对胃癌细胞生物学行为的作用及机制.方法用生物信息学法分析胃癌中LINC00996的表达,及其对胃癌患者总生存期的影响.用RT-qPCR检测胃癌及癌旁组织、胃癌及正常胃上皮细胞系中LINC00996表达.胃癌细胞(SGC7901、NCI-N87)转染针对LINC00996的小干扰RNA(si-LINC00996)和细胞周期蛋白依赖性激酶抑制蛋白2A(cyclin-dependent kinase inhibitor 2A,CDKN2A)的小干扰RNA(si-CDKN2A)后,用细胞计数试剂盒-8法、EDU染色法、流式细胞术法、划痕法和Transwell法分别检测细胞增殖、细胞周期、凋亡、迁移与侵袭;Western blot法检测细胞中CDKN2A、周期蛋白D1、B淋巴细胞瘤-2(B-cell lymphoma-2,Bcl-2)、Bcl-2相关X蛋白(Bcl-2 associated X protein,Bax)和劈开的半胱胺酸蛋白酶-3(Cleaved cysteinyl aspartate-specific proteinase-3,Cleaved caspase-3)表达.结果LINC00996在胃癌组织和细胞中表达较癌旁组织和胃正常细胞系显著升高(P<0.05),Kaplan Meier Plotter数据库显示LINC00996高表达组的胃癌患者的总生存期较低表达组显著缩短(P<0.05).敲降LINC00996能抑制胃癌细胞增殖、细胞周期运行、迁移、侵袭(P<0.05),促进细胞凋亡(P<0.05);降低cyclin D1和Bcl-2表达(P<0.05);升高CDKN2A、Bax和Cleaved caspase-3表达(P<0.05).敲降CDKN2A能部分逆转敲降LINC00996对胃癌细胞的作用(P<0.05).结论敲降LINC00996能通过上调CDKN2A诱导胃癌细胞凋亡,抑制其增殖、迁移与侵袭.

关键词：长基因间非蛋白编码RNA 996 细胞周期蛋白依赖性激酶抑制蛋白2A 胃癌增殖凋亡迁移侵袭

来源：

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

WALL PRESSURE FLUCTUATIONS OF TURBULENT FLOW OVER BACKWARD-FACING STEP WITH AND WITHOUT ENTRAINMENT: MICROPHONE ARRAY MEASUREMENT

引用

Journal of Hydrodynamics 2006年第4期18卷 393-396页

作者： KE Feng LIU Ying-zheng WANG wei-zhe chen Han-ping School of Mechanical and Power Engineering Shanghai Jiaotong University Shanghai 200030 China

Wall pressure fluctuations in turbulent boundary layer flow over backward-facing step with and without entrainment were investigated. Digital array pressure sensors and multi-arrayed microphones were employed to acquire the time-averaged static pressure and fluctuating pressure, respectively. The differences of two flows were scrutinized in terms of static pressure characteristics, pressure fluctuations, cross-correlation and coherence of wall pressure. Introduction of the entrainment increased scale of large-scale vortical structure and reduced its convection velocity. However, shedding frequency of large-scale vortical structures was found to be the same for both flows.

关键词： backward-facing step turbulent boundary layer entrainment wall pressure fluctuations Microphone Array

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Exploring the Effect of Plasticity on the Phase Imaging of TM-AFM Through Molecular Dynamics Simulations

引用

Acta Mechanica Solida Sinica 2024年第2期37卷 297-304页

作者： Guolin Liu Yu Zeng Yaxin chen zheng wei School of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing100029China

In the tapping-mode atomic force microscope(TM-AFM),the probe tip continuously taps the sample surface,which may cause plastic deformation of the sample and result in energy *** energy dissipation of the probe is closely related to the scanned phase *** quantify the energy dissipation due to plastic indentations of the sample,this study utilized a combination of molecular dynamics(MD)simulations and experiments on single-crystal copper samples,including multiple nano-indentation *** energy dissipation of the probe due to the plastic deformation of the sample was calculated by integrating the hysteresis curve of the indentation depth versus the force applied to the *** simulation results are in good agreement with the experimental *** sets of results have demonstrated that the plastic energy dissipation decreases as the number of indentations increases,and eventually the energy of the probe tends to *** equilibrium energy dissipation is associated with other dissipation ***,it was observed that,after hundreds of taps,the dissipated energy of plastic deformation could be ignored,implying that the scanned image may not reflect the plasticity information of the sample after multiple taps of the probe on the sample surface for scanning.

关键词： Atomic force microscopy Force-distance curves Nano-indentations Plasticity Molecular dynamics

来源：

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

UAV swarm air combat maneuver decision-making method based on multi-agent reinforcement learning and transferring

引用

Science China(Information Sciences) 2024年第8期67卷 49-66页

作者： Zhiqiang zheng chen wei Haibin DUAN State Key Laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical Engineering Beihang University

During short-range air combat involving unmanned aircraft vehicle(UAV) swarms, UAVs must make accurate maneuver decisions based on information from both enemy and friendly UAVs. This dual requirement of competition and cooperation presents a significant challenge in the field of unmanned air combat. In this paper, a method based on multi-agent reinforcement learning(MARL) is proposed to address this issue. An actor network containing three subnetworks that can handle different types of situational information is designed. Hence, the results from simpler one-on-one scenarios are leveraged to enhance the complex swarm air combat training process. Separate state spaces for local and global information are designed for the actor and critic networks. A detailed reward function is proposed to encourage *** prevent lazy participants in air combat, a reward assignment operation is applied to distribute these dense rewards. Simulation testing and ablation experiments demonstrate that both the transfer operation and reward assignment operation can effectively deal with the swarm air combat scenario, and reflect the effectiveness of the proposed method.

关键词： UAV swarm short-range air combat multi-agent reinforcement learning reward assignment transfer

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Size control of SBA-15 by tuning the stirring speed for the formation of CMK-3 with distinct adsorption performance

引用

Nano Research 2016年第8期9卷 2294-2302页

作者： Qi Wang Zhencai Wang Tianhao zheng Xiongping Zhou wei chen Dekun Ma Yun Yang Shaoming Huang Key Laboratory of Carbon Materials of Zhejiang Province College of Chemistry and Materials Engineering Wenzhou UniversityWenzhou 325027 China

Controlling the size of SBA-15 can be beneficial for exploiting CMK-3, which has excellent structural parameters, for better performance in adsorption and/or catalytic processes. In this study, the width of freestanding SBA-15 rods was readily and successfully regulated by simply altering the stirring power during the synthesis. A higher stirring rate produced SBA-15 rods with larger width. Then, the size of the CMK-3 rods was adjusted by duplication of the different- sized SBA-15. The results show that the larger sized CMK-3 has higher specific surface area and pore volume, which led to a higher adsorption capacity and a faster adsorption rate. It is believed that the synthetic method reported here is powerful for developing better mesoporous carbon for application in water purification and catalysis.

关键词： SBA-15 CMK-3 size control adsorption

来源：

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

Lift-Off Effect of Koch and Circular Differential Pickup Eddy Current Probes

引用

Chinese Journal of Mechanical Engineering 2024年第2期37卷 283-293页

作者： Guolong chen zheng Cao Shuaishuai Zhang Ji wei wei Gao Wuyin Jin School of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730050China

A flexible or planar eddy current probe with a differential structure can suppress the lift-off noise during the inspection of ***,the extent of the lift-off effect on differential probes,including different coil structures,*** this study,two planar eddy current probes with differential pickup structures and the same size,Koch and circular probes,were used to compare lift-off *** eddy current distributions of the probes perturbed by 0°and 90°cracks were obtained by finite element *** analysis results show that the 90°crack can impede the eddy current induced by the Koch probe even further at relatively low lift-off *** peak-to-peak values of the signal output from the two probes were compared at different lift-off distances using finite element analysis and experimental *** addition,the effects of different frequencies on the lift-off were studied *** results show that the signal peak-to-peak value of the Koch probe for the inspection of cracks in 90°orientation is larger than that of the circular probe when the lift-off distance is smaller than 1.2 *** addition,the influence of the lift-off distance on the peak-to-peak signal value of the two probes was studied via *** indicates that the influence becomes more evident with an increase in excitation *** research discloses the lift-off effect of differential planar eddy current probes with different coil shapes and proves the detection merit of the Koch probe for 90°cracks at low lift-off distances.

关键词： Eddy current testing Differential pickup probe Fractal Koch curve Flexible eddy current probe

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Enhancement of comprehensive properties of Nb-Si based in-situ composites by Ho rare earth doping

引用

Rare Metals 2024年第9期43卷 4508-4520页

作者： wei wei Qi Wang Rui-Run chen Chao-Wen zheng Yan-Qing Su National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

This study examines the microstructure,mechanical properties(with a focus on room-temperature toughness),and oxidation resistance of Ho-doped NbDSi based in-situ *** base alloy consists of the coarse primary Nb_(5)Si_(3)phase and the Nb_(5)Si_(3)+Nbss(Nb solid solution)eutectic *** doping influences the solidification *** the Ho doping is higher than0.2 at%,the alloys transform into eutectic *** can be solid-solved in trace amounts in the Nbss ***,most of Ho forms a stable Ho oxide phase,which alleviates oxygen contamination problem to some ***,the interface separation between Ho oxide and other phases reduces the plastic deformation ***,with 0.4 at%Ho doping,the K_(Q)value is18.03 MPa·m^(1/2),which is 31.1%higher than that of the base *** strength of the Ho-doped alloys does not deteriorate with an increase in ***,the large network-like Ho_(2)O_(3)in the 0.8Ho alloy causes a decrease in toughness and *** addition,the Ho oxide phase effectively blocks the inward oxygen *** 0.8 at%Ho doping,the oxidation mass gain per unit area is 10.16 mg·cm^(2),which is 39.7%lower than that of the base alloy.

关键词： Nb-Si based composites Rare earth elements Ho Microstructure Properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nanomedicine Disrupts Stromal Barriers to Augment Drug Penetration for Improved Cancer Therapy

引用

Chinese Journal of Chemistry 2024年第10期42卷 1175-1189页

作者： Guo-Feng Luo wei-Hai chen Xian-zheng Zhang state Key Laboratory of Oral&Maxillofacial Reconstruction and Regeneration Key Laboratory of Oral Biomedicine Ministry of EducationHubei KeyLaboratory of StomatologySchool&Hospital of StomatologyWuhan UniversityWuhanHubei 430079China Key Laboratoryof Biomedical Polymers of Ministry of Education&Departmentof Chemistry Wuhan UniversityWuhanHubei 430072China

Tumor stroma composing diverse extracellular matrixes(ECM)and stromal cells shapes a condensed physical barrier,which severely hampers the efficient accessibility of nanomedicine to tumor cells,especially these deep-seated in the core of *** barrier significantly compromises the antitumor effects of drug-loaded nanomedicine,revealing the remarkable importance of disrupting stromal barrier for improved tumor therapy with deep penetration *** achieve this goal,various nanoparticle-based strategies have been developed,including direct depleting ECM components via delivering anti-fibrotic agents or targeting stromal cells to suppress ECM expression,dynamic regulation of nanoparticles’physicochemical properties(i.e.,size,surface charge,and morphology),mechanical force-driven deep penetration,natural/biomimetic self-driven nanomedicine,and transcytosis-inducing *** these nanostrategies were systemically summarized in this review,and the design principles for obtaining admirable nanomedicine were *** the rapid development of nanotechnology,elaborate design of multifunctional nanomedicine provides new opportunities for overcoming the critical stromal barriers to maximize the therapeutic index of various therapies,such as chemotherapy,photodynamic therapy,and immunotherapy.

关键词： Nanomedicine Tumor stroma Deep penetration Enhanced drug perfusion Cancer therapy Drug carriers Biomaterials Nanotechnology

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：