检索结果-南通市图书馆

Investigation of Al-based Alloys for Brazing SiC_p/Al Composites

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

稀有金属材料与工程 2011年第S3期40卷 132-135页

作者： Wu Mao1,2, Chang Lingling2, Peng Zirong2, Feng Zelong2, Yong Weina2, Wang Wei2, He Xinbo1,2, Qu Xuanhui1,2 1state key laboratory for Advanced Metals and Materials, University of Science and technology Beijing 100083, China 2 Beijing key laboratory for Powder Metallurgy and Particulate Materials, University of Science and technology Beijing, Beijing 100083, China Univ Sci & Technol Beijing State Key Lab Adv Met & Mat Beijing 100083 Peoples R China Univ Sci & Technol Beijing Beijing Key Lab Powder Met & Particulate Mat Beijing 100083 Peoples R China

The brazing of SiCp/Al composites is limited owing to the unavailability of suitable commercial intermediate temperature brazes. Adding a third constituent of copper to aluminum-silicon brazing alloy can depress the melting point sharply. While, it generates a large volume fraction of the hard Al2Cu intermetallic compounds (IMCs), which makes the alloy brittle and reduces its corrosion resistance. A quaternary addition of nickel that partly substitute for copper can refine grain size significantly, improve the mechanical properties, and without altering the melting range of aluminum-silicon-copper alloy. Al-Cu-Ni-Si braze alloy has been prepared and a fluxless process has been employed to braze SiCp/Al composites that leads to a good bonding strength of brazing joint.

关键词： SiCp/Al composites Al-based brazes brazing intermetallic compounds (IMCs)

维普期刊数据库

The correspondence between the concepts in description logics for contexts and formal concept analysis

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2012年第5期55卷 1106-1122页

作者： MA Yue 1,2,SUI YueFei 1 & CAO CunGen 1 1 key laboratory of intelligent Information Processing,Institute of Computing technology,Chinese Academy of Sciences,Beijing 100190,China 2 Graduate University of Chinese Academy of Sciences,Beijing,China key laboratory of intelligent Information Processing Institute of Computing Technology Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing China

Formal concept analysis (FCA) and description logic (DL) are meant to be formalizations of concepts.A formal concept in the former consists of its intent and extent,where the intent is the set of all the attributes shared by each object in the extent of the concept,and the extent is the set of all the objects sharing each property in the intent of the concept.A concept in the latter formalization is simply a concept name,the interpretation of which is a subset of a *** consider the correspondence between concepts in both formalizations,a multi-valued formal context must be represented both as a knowledge base and as a model of the DL for contexts,where concepts are decomposed into tuple concepts C,interpreted as a set of tuples and value concepts V,interpreted as a set of attribute-value *** show that there is a difference between the interpretation of concepts R.V /R.C and the Galois connection between the extent/intent of formal concepts in *** to the Galois connection,there should be concepts of the form + R.V and + R.C inter-preted in FCA,and hence the logical language L for DL is extended to be L + together with + as a constructor so that + R.V and + R.C are well-defined ***,according to the interpretation in DL there should be pseudo concepts in FCA so that the interpretation of concepts R.V /R.C is the extent/intent of pseudo *** correspondence between formal concepts and concepts in L +,and between pseudo concepts and concepts in L are presented in this paper.

关键词： description logic formal concept analysis concept attribute/role

Power minimization with derivative constraints for high dynamic GPS interference suppression

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2012年第4期55卷 857-866页

作者： WU RenBiao 1,2,LI Chan 1 & LU Dan 1 1 Tianjin key laboratory for Advanced Signal Processing,Civil Aviation University of China,Tianjin 300300,China 2 intelligent Information Institute of ATR lab,Shenzhen University,Shenzhen,518060,China Tianjin key laboratory for Advanced Signal Processing Civil Aviation University of China Tianjin China intelligent Information Institute of ATR lab Shenzhen University Shenzhen China

In this paper,a novel adaptive interference suppression algorithm is proposed for high dynamic GPS (global positioning system) *** new method incorporates derivative constraints on the inter-ference DOA (direction of arrival) into power minimization approach,which could broaden the width of nulls in the interferences directions and adapt to the rapid change of the interference *** with the traditional wide nulling algorithm based on the derivative constraints,the new method does not have to know or estimate the DOAs of the desired signal and the *** new method is firstly discussed in the context of spatial processing,and then extended to space-time adaptive processing to mitigate wideband diffusive multipath *** of the new method is verified via simulation examples.

关键词： GPS interference cancellation adaptive arrays space-time adaptive processing high dynamic GPS receiver

Binary particle swarm optimization with multiple evolutionary strategies

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2012年第11期55卷 2485-2494页

作者： ZHAO Jing1,HAN ChongZhao1 & WEI Bin2 1Ministry of Education key lab For intelligent Networks and Network Security,state key laboratory for Manufacturing systems Engineering,Institute of Integrated Automation,School of Electronics and Information Engineering,Xi'an Jiaotong University,Xi'an 710049,China 2Institute of System Engineering,School of Electronics and Information Engineering,Xi'an Jiaotong University,Xi'an 710049,China Ministry of Education key lab For intelligent Networks and Network Security State Key Laboratory for Manufacturing Systems Engineering Institute of Integrated Automation School of Electronics and Information Engineering Xi’an Jiaotong University Xi’an China Institute of System Engineering School of Electronics and Information Engineering Xi’an Jiaotong University Xi’an China

This paper introduces a novel variation of binary particle swarm optimization(BPSO) algorithm and a further extension to improve its ***,mimicking the behaviors of some creatures group,multiple evolutionary strategies BPSO(MBPSO) is introduced which takes different evolutionary strategies for various particles according to their ***,on the basis of MBPSO,a new strategy is discussed to improve the performance of the MBPSO(M2BPSO) which adopts the concept of the mutation operator aiming to overcome the premature convergence and slow convergent speed during the later stages of the *** proposed two algorithms are tested on seven benchmark functions and their results are compared with those obtained by other *** results show that our methods outperform the other algorithms.

关键词： binary particle swarm optimizer evolutionary strategies swarm intelligence

intelligent Fault Diagnosis Based on Robust Observer

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Intelligent Fault Diagnosis Based on Robust Observer

Efficient DPCA SAR imaging with fast iterative spectrum reconstruction method

2003年中国智能自动化会议

作者： HAO Han Yong, SUN ZengQi (state key lab of intelligent technology and systems, Department of Computer Science and technology, Tsinghua University Beijing, 100084, P.R.China)

With an increasing demand for higher performance, more safety and reliability of dynamic systems, fault diagnosis has received more and more research interests in recent years. In this paper, a slight improvement on algorithm of robust observer is proposed first. Using an instance of the 3-tank system, the robust performance of robust observer is discussed. Then, by applying neural network on choosing of threshold, the adaptability of observer is improved.

关键词： fault diagnosis robust observer neural network

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2012年第8期55卷 1838-1851页

作者： FANG Jian1,ZENG JinShan1,XU ZongBen1&ZHAO Yao2 1M inistry of Education key lab for intelligent Networks and Network Security Xi'an Jiaotong University,Xi'an 710049,China 2N ational key laboratory of Science and technology on Microwave Imaging&Institute of Electronics,Chinese Academy of Sciences,Beijing 100049,China Ministry of Education key lab for intelligent Networks and Network Security Xi’an Jiaotong University Xi’an China National key laboratory of Science and technology on Microwave Imaging & Institute of Electronics Chinese Academy of Sciences Beijing China

The displaced phase center antenna(DPCA)technique is an effective strategy to achieve wide-swath synthetic aperture radar(SAR)imaging with high azimuth ***,traditionally,it requires strict limitation of the pulse repetition frequency(PRF)to avoid non-uniform ***,any deviation could bring serious ambiguity if the data are directly processed using a matched *** break this limitation,a recently proposed spectrum reconstruction method is capable of recovering the true spectrum from the nonuniform ***,the performance is sensitive to the selection of the *** regularization based imaging may provide a way to overcome this *** existing time-domain method,however,requires a large-scale observation matrix to be built,which brings a high computational *** this paper,we propose a frequency domain method,called the iterative spectrum reconstruction method,through integration of the sparse regularization technique with spectrum analysis of the DPCA *** approximately expressing the observation in the frequency domain,which is realized via a series of decoupled linear operations,the method performs SAR imaging which is then not directly based on the observation matrix,which reduces the computational cost from O(N2)to O(N log N)(where N is the number of range cells),and is therefore more efficient than the time domain *** sparse regularization scheme,realized via a fast thresholding iteration,has been adopted in this method,which brings the robustness of the imaging process to the PRF *** provide a series of simulations and ground based experiments to demonstrate the high efficiency and robustness of the *** simulations show that the new method is almost as fast as the traditional mono-channel algorithm,and works well almost independently of the PRF ***,the suggested method can be accepted as a practical and efficient wide-swath SAR imaging technique.

关键词： displaced phase center antenna sparse regularization iterative thresholding spectrum reconstruction

Synthesis of Alkyl4(4'-octyloxy-4”-biphenylcarboxy)-benzenesulfonates

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1998年第8期9卷 711-713页

作者： Zhi Ping LI Guo Du REN(state key laboratory of Fine Chemicals, Dalian University of technology Dalian 116012) state key lab. of Fine Chemicals Dalian University of Technology Dalian 116012 China

Five new Liquid Crystals with sulfonate units were synthesized. And they were detendned by FT-IR and MS. The points of phase transition and the temperatUre ranges of liquid crystals were measured by means of DSC and P... 详细信息

关键词： liquid Crystal sulfonate synthesis

维普期刊数据库

A self-calibration algorithm for cross array in the presence of mutual coupling

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2011年第4期54卷 836-848页

作者： HU XiaoQin 1,2,CHEN Hui 2,WANG YongLiang 2 & CHEN JianWen 2 1 College of Electronic Science and Engineering,National University of Defense technology,Changsha 410073,China 2 key lab of Wuhan Radar Academy,Wuhan 430019,China College of Electronic Science and Engineering National University of Defense Technology Changsha China key lab of Wuhan Radar Academy Wuhan China

In this paper,a novel blind mutual coupling self-calibration algorithm especially tailored to cross array is *** method compensates for the mutual coupling not only between sensors in each subarray but also between two *** the property of coupling matrix,the proposed method requires neither the calibration sources in known locations nor the multidimensional nonlinear *** method can jointly estimate the DOAs of the incoming signals and the unknown mutual coupling coefficients,and has high estimation precision and low computational *** analysis and computer simulations show the effectiveness of the proposed algorithm.

关键词： cross array mutual coupling self-calibration DOA estimation

Long-period Gratings in-situ Sensing for Flow Monitoring in Liquid Composite Molding

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 Materials Science & technology 2005年第2期21卷 234-238页

作者： Yingdan ZHU, Chang WANG, Jihui WANG, Wei HE and Guoqiang GAO state key laboratory of Advanced technology for Materials Synthesis and Proceeding, Wuhan University of technology, Wuhan 430070, China Mat. Synthesis and Proceeding lab. Wuhan Univ. of Technol. Wuhan 430070 China

Liquid composite moulding (LCM) processes are used to manufacture high quality and complex-shaped composite parts in the automotive, marine, aerospace and civil industries. On-line sensing plays an important role in controlling the quality of the final product in the LCM manufacturing environment. The long-period fiber grating (LPG) technology, a new real-time fiber optic sensor system, was developed to monitor the flow front progression. The sensor operation and characterization under various process conditions were discussed in detail. The experimental results showed that LPG sensors were robust and reliable to detect the arrival of resin at pre-selected locations in structures with low-medium fiber volume fraction; however were limited at different depths in structures with high fiber volume fraction.

关键词： Liquid composite moulding Flow monitoring Long-period grating

维普期刊数据库