检索结果-南通市图书馆

Acta Metallurgica Sinica(English Letters) 2018年第8期31卷 807-814页

作者： Lin-Zhi Wang Wen-hou wei Chongqing Key Laboratory of Additive Manufacturing Technology and Systems Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences

Three-dimensional parts of the 30 CrMnSiA steel were successfully fabricated using selective laser melting（SLM）. The microstructures and mechanical properties of the SLM-processed 30 CrMnSiA samples were investigated by scanning electron microscope and transmission electron microscopy. The results indicate that the microstructures of the 30 CrMnSiA samples consist mainly of lath martensite and acicular martensite. The value of the surface roughness decreases with increasing laser energy density（LED） before it reaches a minimum and then increases with further increasing LED. The relative density, microhardness and ultimate tensile strength of the SLM-processed samples initially increase and then decrease with increasing LED. By taking the relative density, surface roughness, microhardness and ultimate tensile strength into account, the optimized LED should be in the range of 46.15–51.28 J mm^（-3） for the SLM-processed30 CrMnSiA alloys. In addition, the differences in the microstructures and mechanical properties between the conventionally wrought 30 CrMnSiA sample and SLM-processed 30 CrMnSiA samples were also studied.

关键词： 30CrMnSiA Selective laser melting Laser energy density Microstructure Mechanical properties

Separation of n-heptane/isobutanol via eco-efficient vapor recompression-assisted distillation:process optimization and control strategy

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2021年第5期15卷 1169-1184页

作者： wei hou Qingjun Zhang Aiwu Zeng State Key Laboratory of Chemical Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin300350China Chemical Engineering Research Center Collaborative Innovative Center of Chemical Science and EngineeringTianjin300072China

In this study,vapor recompression and heat integration assisted distillation arrangements with either the low or high pressure in the reflux drum are proposed to reduce and/or eliminate the application of the costly refrigerant for the separation of n-heptane and isobutanol *** high-pressure arrangement with vapor recompression and heat integration is the most attractive among these four intensified configurations since it can reduce total annual cost by 18.10%,CO_(2) emissions by 75.01%based on natural gas(78.78%based on heavy oil fuel),and second-law efficiency by 61.20%compared to a conventional refrigerated distillation ***,exergy destruction in each component is calculated for the heat integration configurations and is shown in pie *** results demonstrate that the high-pressure configuration presents unique advantages in terms of thermodynamic efficiency compared to the low-pressure *** addition,dynamic control investigation is performed for the economically efficient arrangement and good product compositions are well controlled through a dual-point temperature control strategy with almost negligible product offsets and quick process responses when addressing 20%step changes in production rate and feed *** that there are no composition measurement loops in our developed control schemes.

关键词： n-heptane/isobutanol vapor recompression heat integration low and/or high-pressure options

Second-Order Consensus of Multiple Agents with Coupling Delay

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2009年第1期51卷 101-109页

作者： SU hou-Sheng ZHANG wei Department of Automation Shanghai Jiao Tong University Shanghai 200240 China

In this paper, we investigate two kinds of second-order consensus algorithms for multiple agents with coupling delay under general fixed directed information topology. Stability analysis is performed based on Lyapunov- Krasovskii functional method. Delay-dependent asymptotical stability condition in terms of linear matrix inequalities （LMIs） is derived for the second-order consensus algorithm of delayed dynamical networks. Both delay-independent and delay-dependent asymptotical stability conditions in terms of LMIs are derived for the second-order consensus algorithm with information feedback.

关键词： consensus time delay linear matrix inequality multi-agent systems

Updates on CRISPR-based gene editing in HIV-1/AIDS therapy

在线全文

学校读者我要写书评

暂无评论

Virologica Sinica 2022年第1期37卷 1-10页

作者： Zhihao Zhang wei hou Shuliang Chen Institute of Medical Virology School of Basic Medical SciencesWuhan UniversityWuhan430071China

Although tremendous efforts have been made to prevent and treat HIV-1 infection,HIV-1/AIDS remains a major threat to global human *** combination antiretroviral therapy(cART),although able to suppress HIV-1 replication,cannot eliminate the proviral DNA integrated into the human genome and thus requires lifelong treatment that may lead to various side *** recent years,clustered regularly interspaced short palindromic repeat(CRISPR)-associated nuclease 9(Cas9)related gene-editing systems have been developed and designed as effective ways to treat HIV-1 ***,new gene-targeting tools derived from or functioning like CRISPR/Cas9,including base editor,prime editing,SHERLOCK,DETECTR,PAC-MAN,ABACAS,pfAGO,have been developed and optimized for pathogens detection and diseases ***,we summarize recent studies on HIV-1/AIDS gene therapy and provide more gene-editing targets based on studies relating to the molecular mechanism of HIV-1 *** also identify the strategies and potential applications of these new gene-editing technologies for HIV-1/AIDS treatment in the ***,we discuss the caveats and problems that should be addressed before the clinical use of these versatile CRISPR-based gene targeting ***,we offer alternative solutions to improve the practice of gene targeting in HIV-1/AIDS gene therapy.

关键词： HIV-1/AIDS CRISPR/Cas9 Gene editing Gene therapy

Technical progress of China’s national remote sensing mapping:from mapping western China to national dynamic mapping

在线全文

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2021年第1期24卷 121-133,I0013页

作者： Jixian Zhang Haiyan Gu wei hou Chunquan Cheng National Quality Inspection and Testing Center for Surveying and Mapping Products State BeijingChina Chinese Academy of Surveying and Mapping BeijingChina

Remote sensing mapping is an important research direction in the development of geographic surveying and *** order to successfully implement the project of Mapping Western China(MWC),a technical mapping system has been *** this project,many problems have been solved through technological innovation,such as block adjustment with scarce control points,large-scale aerial/satellite image mapping,and intelligent interpretation of multi-source *** softwares were developed,*** for aerial/satellite image mapping in a large area,FeatureStation for the integration of multi-source data in the complex terrain areas,and an airborne multi-band and multi-polarization interferometric data acquisition system for SAR *** the first time,full coverage of 1:50,000 topographic data of China’s land territory has been produced,which means the geospatial framework of digital China is basically *** the implementation of other key national plans and projects(*** geographic conditions monitoring and national remote sensing mapping),the focus has changed from MWC to national dynamic ***,a dynamic mapping system is *** data acquisition capability has developed from a single source to multiple sources and multiple *** mapping capability has developed into dynamic mapping,and the capability for database update shows the characteristics of *** national geographic condition monitoring creates a multi-scale index system for statistical analysis for various needs.A multi-level and multi-dimensional technical system for statistical computing and decision-making service is developed for the transformation from dynamic monitoring to information *** this paper,we give a brief introduction about the recent development of remote sensing mapping in China with respect to data acquisition,map production,and information *** purpose of this paper is to motivate the establishment

关键词： Remote sensing mapping mapping western China national dynamic monitoring data acquisition image interpretation information service

Atmospheric Circulation Patterns over East Asia and Their Connection with Summer Precipitation and Surface Air Temperature in Eastern China during 1961–2013

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 Meteorological Research 2018年第2期32卷 203-218页

作者： Shuping LI wei hou Guolin FENG College of Atmospheric Sciences Lanzhou University Lanzhou 730000 National Climate Center China Meteorological Administration Beijing 100081 College of Physical Science and Technology Yangzhou University Yangzhou 225000

Based on the NCEP/NCAR reanalysis data and Chinese observational data during 1961–2013, atmospheric circulation patterns over East Asia in summer and their connection with precipitation and surface air temperature in eastern China as well as associated external forcing are investigated. Three patterns of the atmospheric circulation are identified, all with quasi-barotropic structures：（1） the East Asia/Pacific（EAP） pattern,（2） the Baikal Lake/Okhotsk Sea（BLOS） pattern, and（3） the eastern China/northern Okhotsk Sea（ECNOS） pattern. The positive EAP pattern significantly increases precipitation over the Yangtze River valley and favors cooling north of the Yangtze River and warming south of the Yangtze River in summer. The warm sea surface temperature anomalies over the tropical Indian Ocean suppress convection over the northwestern subtropical Pacific through the Ekman divergence induced by a Kelvin wave and excite the EAP pattern. The positive BLOS pattern is associated with below-average precipitation south of the Yangtze River and robust cooling over northeastern China. This pattern is triggered by anomalous spring sea ice concentration in the northern Barents Sea. The anomalous sea ice concentration contributes to a Rossby wave activity flux originating from the Greenland Sea, which propagates eastward to North Pacific. The positive ECNOS pattern leads to below-average precipitation and significant warming over northeastern China in summer. The reduced soil moisture associated with the earlier spring snowmelt enhances surface warming over Mongolia and northeastern China and the later spring snowmelt leads to surface cooling over Far East in summer, both of which are responsible for the formation of the ECNOS pattern.

关键词： atmospheric circulation patterns precipitation surface air temperature external forcing

Constitutive model for overconsolidated clays

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2008年第2期51卷 179-191页

作者： YAO YangPing hou wei Zhou AnNan Department of Civil Engineering Beihang UniversityBeijing 100083China

Based on the relationships between the Hvorslev envelope,the current yield sur-face and the reference yield surface,a new constitutive model for overconsolidated clays is proposed. It adopts the unified hardening parameter,to which the potential failure stress ratio and the characteristic state stress ratio are introduced. The model can describe many characteristics of overconsolidated clays,including stress-strain relationships,strain hardening and softening,stress dilatancy,and stress path dependency. Compared with the Cam-clay model,the model only re-quires one additional soil parameter which is the slope of the Hvorslev envelope. Comparisons with data from triaxial drained compression tests for Fujinomori clay show that the proposed model can rationally describe overconsolidated properties. In addition,the model is also used to predict the stress-strain relationship in the isotropic consolidation condition and the stress paths in the undrained triaxial compression tests.

关键词： overconsolidated clays current yield surface reference yield surface unified hardening parameter Hvorslev envelope.

Electrochem ically Enabled Intram olecular Am inooxygenation of Alkynes v ia Am idyl Radical Cyclization

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2020年第4期38卷 394-398页

作者： Zhong-wei hou Hai-Chao Xu State Key Laboratory of Physical Chemistry of Solid Surfaces iChEMKey Laboratory of Chemical Biology of Fujian Provinceand College of Chemistry and Chemical EngineeringXiamen UniversityXiamenFujian 361005Chino

Summary of main observation and conclusion An electrochemical synthesis of oxazol-2-ones and imidazol-2-ones has been developed via 5-exo-dig cyclization of propargylic carbamates-and ureas-derived amidyl *** electrosynthesis relies on the dual function of 2,2,66-tetramethylpiperidin-1-y oxyl(TEMPO)as a redox mediator for amidyl radical formation and an oxygen atom *** reactions are conducted under mild conditions using a simple setup and provide convenient access to functionalized oxazol-2-ones and imidazol-2-ones from readily available materials.

关键词： materials. donor readily

Integrated Virtual Assembly Process Planning System

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

Chinese Journal of Mechanical Engineering 2009年第5期22卷 717-728页

作者： LIU Jianhua hou weiwei SHANG wei NING Ruxin School of Mechanical Engineering Beijing Institute of Technology Beijing 100081 China

Assembly process planning（APP） for complicated products is a time-consuming and difficult work with conventional method. Virtual assembly process planning（VAPP） provides engineers a new and efficiency way. Previous studies in VAPP are almost isolated and dispersive, and have not established a whole understanding and discussed key realization techniques of VAPP from a systemic and integrated view. The integrated virtual assembly process planning（IVAPP） system is a new virtual reality based engineering application, which offers engineers an efficient, intuitive, immersive and integrated method for assembly process planning in a virtual environment. Based on analysis the information integration requirement of VAPP, the architecture of IVAPP is proposed. Through the integrated structure, IVAPP system can realize information integration and workflow controlling. In order to mode/the assembly process in IVAPP, a hierarchical assembly task list（HATL） is presented, in which different assembly tasks for assembling different components are organized into a hierarchical list. A process-oriented automatic geometrical constraint recognition algorithm（AGCR） is proposed, so that geometrical constraints between components can be automatically recognized during the process of interactive assembling. At the same time, a progressive hierarchical reasoning（PHR） model is discussed. AGCR and PHR will greatly reduce the interactive workload. A discrete control node model（DCNM） for cable harness assembly planning in IVAPP is detailed. DCNM converts a cable harness into continuous flexed line segments connected by a series of section center points, and designs can realize cable harness planning through controlling those control nodes. Mechanical assemblies （such as transmission case and engine of automobile） are used to illustrate the feasibility of the proposed method and algorithms. The application of IVAPP system reveals advantages over the traditional assembly process planning method in

关键词： virtual assembly assembly model assembly task collision detection automatic constraint recognition cable harness assembly process planning

Relationship between dispersibility of ZrO2 nanoparticles in Ni-ZrO2 electroplated nanocomposite coatings and mechanical properties of nanocomposite coatings

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2004年第z1期14卷 186-189页

作者： WANG wei hou Feng-yan GUO He-tong School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

Ni-ZrO2 nanocomposite coatings with monodispersed ZrO2 nanoparticles were prepared from the composite plating bath containing dispersant under DC electrodeposition condition. It is found that the morphology, orientation and hardness of the composite coating with monodispersed ZrO2 nanoparticles have lots of difference from the composite coating with agglomerated ZrO2 nanoparticles and pure nickel coating. Especially, the result of hardness shows that only a very low volume fraction (less than 1%) of monodispered ZrO2 nanoparticles in Ni-ZrO2 composite coatings will result in higher hardness of the coating. The hardness of Ni-ZrO2 nanocomposite coatings with monodispersed and agglomerated ZrO2 nanoparticles are HV 529 and HV 393, respectively. The hardness value of the former composite coatings is over 1.3 times higher than that of the later. All these composite coatings are 2 - 3 times higher than that of pure nickel plating (HV 207) prepared under the same conditions.

关键词： Nanocomposites electroplating coating metal matrix composites Ni-ZrO2