检索结果-南通市图书馆

Prediction of Maximum Section Flattening of Thin-walled Circular Steel Tube in Continuous Rotary Straightening Process

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2016年第8期23卷 745-755页

作者： Zi-qian ZHANG School of Mechanical Engineering and Automation Northeastern University

Cross-sectional ovalization of thin-walled circular steel tube because of large plastic bending,also known as the Brazier effect,usually occurs during the initial stage of tube′s continuous rotary straightening *** amount of ovalization,defined as maximal cross section flattening,is an important technical parameter in tube′s straightening process to control tube′s bending deformation and prevent ***,for the lack of special analytical model,the maximal section flattening was determined in accordance with the specified charts developed by experienced operators on the basis of experimental data;thus,it was inevitable that the localized buckling might occur during some actual straightening *** normal strain component formulas were derived based on the thin shell ***,strain energy of thin-walled tube（per unit length）was obtained using the elastic-plastic theory.A rational model for predicting the maximal section flattening of the thin-walled circular steel tube under its straightening process was presented by the principle of minimum potential *** new model was validated by experiments and numerical *** results show that the new model agrees well with the experiments and the numerical simulations with error of less than 10%.This new model was expected to find its potential application in thin-walled steel tube straightening machine design.

关键词： walled Rotary bending buckling length maximal radius localized Prediction rotary

Local Covering Subgroups in Finite Groups

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2021年第5期37卷 768-774页

作者： Guo Hua qian Department of Mathematics Changshu Institute of TechnologyChangshu 215500P.R.China

A subgroup A of a finite group G is called a local covering subgroup of G if A^(G)=AB for all maximal G-invariant subgroup B of A^(G)=(A^(G),g∈G).Let p be a prime and d be a positive *** that all subgroups of p^(d),and all cyclic subgroups of order 4 when p^(d)=2 and a Sylow2-subgroup of G is nonabelian,of G are local covering *** G is p-supersolvable whenever p^(d)=p or p^(d)≤(√|G|_(p))or p^(d)≤|O_(p'p)(G)|_(p)/p.

关键词： Finite group local covering subgroup p-supersolvable group

Why does nitrogen-doped graphene oxide lose the antibacterial activity?

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第3期62卷 44-51页

作者： Jiajun Qiu Lu Liu Shi qian Wenhao qian Xuanyong Liu State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Shanghai Xuhui District Dental Center Shanghai 200032China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Graphene and its derivatives attract extensive research interests in the biomedicine field due to their outstanding physiochemical *** of studies have reported that graphene materials exhibit antibacterial ***,antibacterial mechanisms of graphene materials still remain controversial and need further ***,graphene oxide(GO)with and without nitrogen-doping were fabricated on the titanium surface by cathodic electro phoretic deposition and antibacterial activities were systematically *** showed that GO on the titanium surface presented antibacterial activity,while nitrogen-doped GO lost the antibacterial *** reason is that antibacterial mechanisms for the GO-metal system contain two ***,electron transfer occurs from bacterium's cell membrane to GO surface which destroys the bacterial respiratory chain;subsequently,electrons on GO surface induce the production of reactive oxygen species(ROS)that damage the membrane structure and eventually lead to bacterial *** nitrogen-doped GO,nitrogen atoms denote electrons into GO leading to n-type ***-doped GO as an electron donor cuts off the electron transfer from the cell membrane to GO and subsequently inhibits the production of *** is why nitrogen-doped GO exhibits no antibacterial *** work confirms the antibacterial mecha nisms for the GO-metal system with a synergistic effect of non-oxidative electron transfer and ROS mediated oxidative stress.

关键词： Graphene oxide Nitrogen-doping Antibacterial activity Electron transfer Reactive oxygen species

Design and Implementation of Secure and Reliable Information Interaction Architecture for Digital Twins

在线全文

学校读者我要写书评

暂无评论

China Communications 2023年第2期20卷 79-93页

作者： qian Wang Wanwan Wu Liping qian Yiming Cai Jiang qian Limin Meng College of Information Engineering Zhejiang University of TechnologyHangzhou 310023China

In order to improve the comprehensive defense capability of data security in digital twins(DTs),an information security interaction architecture is proposed in this paper to solve the inadequacy of data protection and transmission mechanism at ***,based on the advanced encryption standard(AES)encryption,we use the keystore to expand the traditional key,and use the digital pointer to avoid the key transmission in a wireless ***,the identity authentication technology is adopted to ensure the data integrity,and an automatic retransmission mechanism is added for the endogenous properties of the wireless ***,the software defined radio(SDR)platform composed of universal software radio peripheral(USRP)and GNU radio is used to simulate the data interaction between the physical entity and the virtual *** numerical results show that the DTs architecture can guarantee the encrypted data transmitted completely and decrypted accurately with high efficiency and reliability,thus providing a basis for intelligent and secure information interaction for DTs in the future.

关键词： digital twins AES encryption digital pointer identity authentication automatic retransmission SDR

A Hardy–Trudinger–Moser Inequality Involving LpNorm in the Hyperbolic Space

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2020年第6期36卷 711-722页

作者： qian Jin LUO Department of Mathematics Renmin University of ChinaBeijing 100872P.R.China

Let B be the unit disc in R2,H be the completion of C0∞(B)under the norm||u||=(∫B|▽U|^2dx-∫Bu^2/(1-|x|^2)^2dx)^1/2,U∈C^∞0(B).By the method of blow-up analysis and an argument of rearrangement with respect to the standard hyperbolic metric dv=dx/(1-|x|^2)^2,we prove that,for any fixedα,0≤α*** is an analog of early results of Lu–Yang(Discrete ***.,2009)and Yang(***.,2007),and extends those of Wang–Ye(***.,2012)and Yang–Zhu(*** ***.,2016).

关键词： Hardy–Trudinger–Moser inequality blow-up analysis Hardy space

先秦时期西南民族交往交流交融研究——以什邡古蜀铜戈铭文释读为例

在线全文

学校读者我要写书评

暂无评论

文史杂志 2025年第1期235卷 33-39页

作者：徐晨钱玉趾西南民族大学民族学与社会学学院四川省科学技术学会

四川什邡是古蜀腹地,什邡城关战国秦汉墓地编号为M59:21的AVI式铭文戈是从楚式戈演变而来的战国晚期蜀戈。戈上5个字符竖刻在胡部,系古蜀文字。古蜀族与彝族有亲缘关系。用彝文字符比对,借助“左言”(主语·宾语·谓语)语序,可以将什邡... 详细信息

四川什邡是古蜀腹地,什邡城关战国秦汉墓地编号为M59:21的AVI式铭文戈是从楚式戈演变而来的战国晚期蜀戈。戈上5个字符竖刻在胡部,系古蜀文字。古蜀族与彝族有亲缘关系。用彝文字符比对,借助“左言”(主语·宾语·谓语)语序,可以将什邡戈铭文释读为“虎(王)用以战斗的锋利铜戈”。铜戈也是中华民族共同体形成与发展的实物例证。

关键词：什邡铭文戈战国晚期铭文释读民族互融

Recent Progress on Rice Genetics in China

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2007年第6期49卷 776-790页

作者： Hua Jiang Long-Biao Guo qian qian State Key Laboratory of Rice Biology China National Rice Research Institute Hangzhou 310006 China The Agricultural College Yangzhou University Yangzhou 225006 China

Through thousands of years of evolution and cultivation, tremendously rich genetic diversity has been accumulated in rice （Oryza sativa L.）, developing a large germplasm pool from which people can select varieties with morphologies of Interest and other important agronomic traits. With the development of modern genetics, scientists have paid more attention to the genetic value of these elite varieties and germplasms, and such rich rice resources provide a good foundation for genetic research in China. Approximately 100 000 accessions of radiation-, chemical- or insertion-induced mutagenesis have been generated since the 1980s, and great progress has been made on rice molecular genetics. So far at least 16 variant/mutant genes Including MOC1, BC1, SKC1, and Rfgenes have been isolated and characterized in China. These achievements greatly promote the research on functional genomics, understanding the mechanism of plant development and molecular design breeding of rice in China. Here we review the progress of three aspects of rice genetics in China： moving forward at the molecular level, genetic research on elite varieties and germplasms, and new gene screening and genetic analysis using mutants. The prospects of rice genetics are also discussed.

关键词： functional genomics genetics germplasm resources rice (Oryza sativa).

Revolutionizing photothermal CO_(2)hydrogenation with ceria-based catalysts

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

Nano Research 2025年第1期18卷 30-49页

作者： Zhaorui Zhang Xiao Han Junhong Zhang Yunyun Dong Jinsheng Zhao qian Xu ingqiang Zhang School of Chemistry and Chemical Engineering Liaocheng UniversityLiaocheng 252059China Institute for Catalysis Hokkaido UniversityN-21W-10Sapporo 001-0021Japan National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China

In the context of achieving carbon neutrality,CO_(2)catalytic conversion technologies are effective in reducing atmospheric CO_(2)concentrations while simultaneously producing renewable *** approach is seen as a viable method for constructing a new carbon cycle,thereby effectively addressing the issue of global *** CO_(2)conversion has recently emerged as a promising research focus due to its high energy utilization efficiency,superior CO_(2)conversion,excellent product selectivity,mild operating conditions,low energy consumption and minimal operating *** oxide(CeO_(2))has been widely used in photothermal catalysis due to its unique chemical properties,particularly when used as a support material with supported metals,creating distinctive interfacial sites for catalytic *** an emerging star support in photothermal CO_(2)conversion,its contributions are equally significant and should not be ***,to our knowledge,there has been no comprehensive review of CeO_(2)applications in catalytic hydrogenation of CO_(2).In this paper,we summarize and discuss CeO_(2)-based materials for photothermal CO_(2)conversion to value-added *** research particularly focuses on the synthesis methods of CeO_(2)-supported catalysts,the history of CeO_(2)in photothermal catalysis,types of photothermal catalytic reactors,unique characterization methods for the photothermal catalysts and the photothermal CO_(2)hydrogenation reactions by CeO_(2)-based *** related to further challenges and future directions for photothermal CO_(2)hydrogenation are also provided.

关键词： CO_(2)neutrality hydrogenation photothermal catalysis ceria C1 chemistry

Improving multiprocessor performance with fine-grain coherence bypass

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

Science China(Information Sciences) 2015年第1期58卷 84-98页

作者： WANG Hui WANG Rui LUAN ZhongZhi qian XueHai qian DePei Sino-German Joint Software Institute School of Computer Science and EngineeringBeihang University University of Illinois Urbana-Champaign

Efficient and scalable cache coherence protocol is crucial to high-performance servers with sharedmemory. The directory-based cache coherence protocol is more desirable than the snooping-based protocol with respect to the scalability. However, even for the former protocol, scaling to a large number of cores is also challenging due to the additional area requirements of the directories. We observed that a significant percentage of the referenced memory blocks were only accessed by a single core(even in parallel applications) which could be considered as private memory blocks. An intuitive motivation from this observation is that memory blocks accessed by a single core do not require coherence maintenance. The issue is to identify the private block and track the change of its access pattern. We propose a novel hardware approach to(1) dynamically identify the shared memory blocks at the cache block level, and(2) bypass the coherence procedure for the private memory blocks. This approach increases the effectiveness of the directory-based approach and therefore improves the system performance. Experimental results showed that, our approach can on an average(1) avoid the coherence tracking of about 54% referenced memory blocks,(2) reduce the coherence overhead by 77%,(3) avoid 8% L2 cache misses, and(4) shorten the execution time of parallel applications by 13%.

关键词： many-core cache coherence private memory block fine-grain coherence high performance