检索结果-南通市图书馆

A Simplified Nonlinear Model of Vertical Vortex-Induced Force on Box Decks for Predicting Stable Amplitudes of Vortex-Induced Vibrations

引用

Engineering 2017年第6期3卷 854-862页

作者： Le-Dong Zhu Xiao-Liang Meng lin-qing du Ming-Chang Ding State Key Laboratory of Disaster Reduction in Civil Engineering & Department of Bridge Engineering College of Civil Engineering & Key Laboratory for Wind Resistance Technology of Bridges of Ministry of Transport Tongji University Shanghai 200092 China Shanghai Urban Construction Municipal Engineering (Croup) Co. Ltd. Shanghai 200065 China Tongji Architectural Design (Group) Co. Ltd. Shanghai 200092 China Highway Planning Survey Design and Research Institute Sichuan Provincial Transport Department Chengdu 610041 China

Wind-tunnel tests of a large-scale sectional model with synchronous measurements of force and vibration responses were carried out to investigate the nonlinear behaviors of vertical vortex-induced forces （VIFs） on three typical box decks （i.e., fully closed box, centrally slotted box, and semi-closed box）. The mechanisms of the onset, development, and self-limiting phenomenon of the vertical vortex-induced vibration （VlV） were also explored by analyzing the energy evolution of different vertical VIF components and their contributions to the vertical VIV responses. The results show that the nonlinear components of the vertical VIF often differ from deck to deck; the most important components of the vertical VIF, governing the stable amplitudes of the vertical VIV responses, are the linear and cubic components of velocity contained in the self-excited aerodynamic damping forces. The former provides a constant negative damping ratio to the vibration system and is thus the essential power driving the development of the VIV amplitude, while the latter provides a positive damping ratio proportional to the square of the vibration velocity and is actually the inherent factor making the VIV amplitude self-limiting. On these bases, a universal simplified nonlinear mathematical model of the vertical VIF on box decks of bridges is presented and verified in this paper; it can be used to predict the stable amplitudes of the vertical VIV of long-span bridges with satisfactory accuracy.

关键词： Box deck of bridge Vertical vortex-induced vibration Vertical vortex-induced force Simplified nonlinear model Wind-tunnel test Large-scale sectional model Synchronous measurement of force and vibration

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

Locally Transitive Graphs Admitting a Group with Cyclic Sylow Subgroups

引用

Communications in Mathematical Research 2010年第3期26卷 239-254页

作者： CHEN SHANG-DI FENG qing-lin du Xian-kun College of Science Civil Aviation University of China Tianjin 300300

All graphs are finite simple undirected and of no isolated vertices in this paper. Using the theory of coset graphs and permutation groups, it is completed that a classification of locally transitive graphs admitting a non-Abelian group with cyclic Sylow subgroups. They are either the union of the family of arc-transitive graphs, or the union of the family of bipartite edge-transitive graphs.

关键词： graph locally-transitive-graph Sylow subgroup cyclic group

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

Enhanced mechanical properties of lamellar Cu/Al composites processed via high-temperature accumulative roll bonding

引用

Transactions of Nonferrous Metals Society of China 2019年第8期29卷 1621-1630页

作者： lin WANG qing-lin du Chang LI Xiao-hui CUI Xing ZHAO Hai-liang YU State Key Laboratory of High Performance Complex Manufacturing Central South University Changsha 410083 China College of Mechanical and Electrical Engineering Central South University Changsha 410083 China Light Alloys Research Institute Central South University Changsha 410083 China

Cu/Al multilayers were produced by high-temperature accumulative roll bonding(ARB)methods up to three *** achieve a high bonding strength,prior to ARB processing,the Cu and Al sheets were heated to 350,400,450 and 500 ℃,*** mechanical properties were evaluated by tensile *** microstructure was examined by optical microscopy and scanning electron microscopy equipped with energy dispersive *** ultimate tensile stress,the grain size and the thickness of diffusion layer of lamellar composites increase with rolling *** the rolling temperature is 400 ℃,the laminates show the highest ductility,but the yield stress is the *** the rolling temperature further increases,both the yield stress and the ultimate tensile stress increase and the ductility decreases *** mechanical properties of lamellar composites processed by low and high temperature ARB are determined by grain size and the thickness of diffusion layer,respectively.

关键词： diffusion layer Cu/Al multilayers accumulative roll bonding rolling temperature intermetallics mechanical 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

Fabrication of ultrafine-grained AA1060 sheets via accumulative roll bonding with subsequent cryorolling

引用

Transactions of Nonferrous Metals Society of China 2021年第11期31卷 3370-3379页

作者： qing-lin du Chang LI Xiao-hui CUI Charlie KONG Hai-liang YU State Key Laboratory of High Performance Complex Manufacturing College of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China Light Alloys Research Institute Central South UniversityChangsha 410083China College of Mechanical Engineering Hunan Institute of Science and TechnologyYueyang 414000China Mark Wainwright Analytical Centre University of New South WalesSydneyNSW 2052Australia

Ultrafine-grained(UFG)AA1060 sheets were fabricated via five-cycle accumulative roll bonding(ARB)and subsequent three-pass cold rolling(298 K),or cryorolling(83 K and 173 K).Microstructures of the aluminum samples were examined via transmission electron microscopy,and their mechanical properties were measured via tensile and microhardness *** indicate that ultrafine grains in ARB-processed sheets were further refined by subsequent rolling,and the grain size became finer with reducing rolling *** mean grain size of 666 nm in the sheets subjected to ARB was refined to 346 or 266 nm,respectively,via subsequent cold rolling or cryorolling(83 K).Subsequent cryorolling resulted in ultrafine-grained sheets of higher strength and ductility than those of the sheets subjected to cold rolling.

关键词： microstructure AA1060 sheet ultrafine-grained materials cryorolling accumulative roll bonding

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

Infiltration by monocytes of the central nervous system and its role in multiple sclerosis: reflections on therapeutic strategies

引用

Neural Regeneration Research 2025年第3期20卷 779-793页

作者： Guangyong Zhang qing Yao Chubing Long Pengcheng Yi Jiali Song Luojia Wu Wei Wan Xiuqin Rao Yue lin Gen Wei Jun Ying Fuzhou Hua Department of Anesthesiology the Second Affiliated Hospital of Nanchang UniversityNanchangJiangxi ProvinceChina Key Laboratory of Anesthesiology of Jiangxi Province NanchangJiangxi ProvinceChina

Mononuclear macrophage infiltration in the central nervous system is a prominent feature of neuroinflammation. Recent studies on the pathogenesis and progression of multiple sclerosis have highlighted the multiple roles of mononuclear macrophages in the neuroinflammatory process. Monocytes play a significant role in neuroinflammation, and managing neuroinflammation by manipulating peripheral monocytes stands out as an effective strategy for the treatment of multiple sclerosis, leading to improved patient outcomes. This review outlines the steps involved in the entry of myeloid monocytes into the central nervous system that are targets for effective intervention: the activation of bone marrow hematopoiesis, migration of monocytes in the blood, and penetration of the blood–brain barrier by monocytes. Finally, we summarize the different monocyte subpopulations and their effects on the central nervous system based on phenotypic differences. As activated microglia resemble monocyte-derived macrophages, it is important to accurately identify the role of monocyte-derived macrophages in disease. Depending on the roles played by monocyte-derived macrophages at different stages of the disease, several of these processes can be interrupted to limit neuroinflammation and improve patient prognosis. Here, we discuss possible strategies to target monocytes in neurological diseases, focusing on three key aspects of monocyte infiltration into the central nervous system, to provide new ideas for the treatment of neurodegenerative diseases.

关键词： blood–brain barrier macrophages monocytes multiple sclerosis neuroinflammation review therapy

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

某天然植物性洗洁精的毒性研究

引用

中国职业医学 2003年第3期30卷 39-41页

作者：夏清林杜琰琰李少群周颖麦惠霞广州市疾病预防控制中心广东广州510080

目的　对某天然植物性洗洁精进行毒性研究。方法　按GB15 193 -1994《食品安全性毒理学评价程序和方法》进行。结果　本品经口LD50 >2 0g/kg ,属无毒级 :未见有致突变作用 ;3 0d喂养试验显示对动物体重、血常规及肝、肾功能等无明显影... 详细信息

目的　对某天然植物性洗洁精进行毒性研究。方法　按GB15 193 -1994《食品安全性毒理学评价程序和方法》进行。结果　本品经口LD50 >2 0g/kg ,属无毒级 :未见有致突变作用 ;3 0d喂养试验显示对动物体重、血常规及肝、肾功能等无明显影响 ;病理学检查结果显示对肾、睾丸组织细胞有轻度毒性作用。结论　该天然植物性洗洁精是一种基本无毒的产品 ,但对肾、睾丸组织的损害作用有待作进一步的毒性研究。

关键词：天然植物性洗洁精毒性精子畸形试验

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

Modeling and experimental validation of vertical landing reusable launch vehicle under symmetric landing conditions

引用

Chinese Journal of Aeronautics 2022年第12期35卷 156-172页

作者： Shuai YUE qing lin Guang ZHENG Zhonghua du School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China Aerospace System Engineering Shanghai Shanghai 201109China Key Laboratory of Impact and Safety Engineering Ministry of EducationNingbo UniversityNingbo 315211China

This paper illustrates the dynamic modeling,experimental validation of Reusable Launch Vehicle under symmetric landing ***,a new quasi-3D dynamic landing model of vehicle under 2-2 and 1-2-1 symmetric landing mode is established,which can predict the plane motion of the main body and the spatial motion of landing struts and *** strut force,footpad-ground contact force and the liquid spring damper are also included in the ***,the landing impact experiments are performed for 2-2 and 1-2-1 symmetric landing *** main and auxiliary strut force are obtained,along with the force-stroke diagram of *** comparing with experimental data,the accuracy of simulation model is *** is found that the simulation model possesses good match with tested responses in damping stroke and main strut *** simulation and experiment also indicate the same trend in auxiliary strut force and main body *** main discrepancies attribute to the simplified structural flexibility and nonlinear contact。

关键词： Dynamics Impact Landing gear Launch vehicle Modeling

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

Safety evaluation of Dagangshan arch dam resisting strong earthquakes with a rate-dependency anisotropic damage model

引用

Science China(Technological Sciences) 2011年第3期54卷 531-540页

作者： du RongQiang ZHANG qing CHEN ShiHai lin Gao Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation Shandong University of Science and Technology Qingdao 266510 China Department of Engineering Mechanics HoHai University Nanjing 210098 China School of Civil and Hydraulic Engineering Dalian University of Technology Dalian 116024 China

This paper presents a model to simulate the safe behavior of Dagangshan arch dam with a rate-dependency anisotropic damage model. This model considers the damage of asymmetry and anisotropy under cyclic loading of tension and compression, and it is used in the compiled finite element code. The material parameters used in the model can be identified from uniaxial static and dynamic experiments. Thereafter, it is used for analyzing damage and failure patterns of the dam subjected to water pressure and strong earthquakes. The numerical results show that it is necessary to consider both asymmetry between tension and compression and anisotropy of damage. Severe damage regions of the dam reveal brittle and risky positions clearly. Meanwhile damage patterns show the failure trend and safety behaviors of the dam. These results match well with that of the experiments carried out in duT. The proposed model may be used to predict the damage patterns and potential failure modes of concrete structures like the dam. And the aseismic performance of the dam can be figured out.

关键词： concrete Dagangshan arch dam anisotropic damage failure criteria strain rate-dependency earthquake unilateral effect

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

Temperature effect on the kinetics of persulfate oxidation of p-chloroaniline

引用

Chinese Chemical Letters 2011年第3期22卷 358-361页

作者： Yong qing Zhang Xiao Zhe du Wei lin Huang College of Environmental Science and Engineering South China University of Technology Guangzhou 510006 China The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters Ministry of Education Guangzhou 510006 China Department of Environmental Sciences Rutgers. The State University of New Jersey New Brunswick NJ 08901 USA

The kinetics of heat-facilitated persulfate oxidation of p-chloroaniline（PCA） in aqueous solutions was measured at five different temperature conditions and at four different oxidant *** PCA degradation was found to follow a pseudo-first-order decay model when the persulfate was *** pseudo-first-order rate constants of PCA degradation by persulfate（50 mmol/ L） at pH 7.0 are 0.12×10^-4,0.28×10^-4,0.43×10^-4,0.83×10^-4,1.32×10^-4 s^-1 at 10,20,30,40 and 50℃,respectively. Under the above reaction conditions,the reaction has activation energy of 49.97 kJ/*** observed rate was found to be function of temperature and oxidant *** temperature and increasing persulfate concentration can significantly accelerate the PCA degradation.

关键词： Persulfate p-Chloroaniline Kinetics In situ chemical oxidation Temperature

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

Solar radio filtering algorithm based on improved long short-term memory

引用

Research in Astronomy and Astrophysics 2021年第4期21卷 79-92页

作者： qing-Fu du Qiao-Man Zhang Xin Li Chang-lin Gao School of Mechanical Electrical&Information EngineeringShandong UniversityWeihai 264209China

The effective observation of burst events in solar radio research has been impeded by various interference signals,especially interference signals with a wide frequency range and high intensity,as they can partially or completely obscure the observation of burst *** processing methods that directly remove the interference signal channels and subtract the average of the interference signal channel are not suitable for processing all types of interference *** paper proposes the use of a specific kind of recurrent neural networks,called long short-term memory networks,to predict the value of the radio frequency interference signals with high intensity of the burst event in the solar radio *** predicted interference can then be removed in accordance with the principle that signals can be linearly ***,predicted value is subtracted from the data containing the burst event signals and the RFI signals(The radio frequency interference signals to be processed in this article refer to the signal of the broadcast signal that can be received in the frequency range,the signal transmitted by the mobile phone,and the signal transmitted by the sea vessel,and the like)to remove the ***,in order to reduce the error caused by the stepwise prediction in the network and further improve the prediction accuracy,this paper analyzes the characteristics of the value of the radio interference and applies the digital mapping method to convert the prediction problem into the classification problem in the time *** experimental results show that the proposed method can effectively remove the radio interference in the solar spectrum and clearly show the burst events.

关键词： Sun:radio radiation methods:data analysis techniques:image processing

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

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：