检索结果-南通市图书馆

Risk transmission evaluation for parallel construction of warships based on IFCM and the cloud model

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2022年第6期33卷 1224-1237页

作者： gong jun HU Tao YAO Lu Department of Management Engineering and Equipment Economics Naval University of EngineeringWuhan 430033China

To cope with multi-directional transmission coupling,spreading, amplification, and chain reaction of risks during multiproject parallel construction of warships, a risk transmission evaluation method is proposed, which integrates an intuitionistic cloud model with a fuzzy cognitive map. By virtue of expectancy Ex, entropy En, and hyper entropy He, the risk fuzziness and randomness of the knowledge of experts are organically combined to develop a method for converting bi-linguistic variable decision-making information into the quantitative information of the intuitionistic normal cloud(INC) model. Subsequently, the threshold function and weighted summation operation in the traditional fuzzy cognitive map is converted into the INC ordered weighted averaging operator to create the risk transmission model based on the intuitionistic fuzzy cognitive map(IFCM) and the algorithm for solving it. Subsequently, the risk influence sequencing method based on INC and the risk rating method based on nearness are proposed on the basis of Monte Carlo simulation in order to realize the mutual conversion of the qualitative and quantitative information in the risk evaluation *** analysis is presented to verify the effectiveness and practicality of the methods.

关键词： risk evaluation multi-project parallel intuitionistic fuzzy cognitive map(IFCM) intuitionistic normal cloud(INC)model warship construction.

Co-based Amorphous/Nanocrystalline Composite Coatings Deposited by Arc Ion Plating

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2013年第9期29卷 806-812页

作者： Zhengkai Chang jun gong Chao Sun State Key Laboratory for Corrosion and Protection Institute of Metal ResearchChinese Academy of Sciences

Cobalt-based amorphous/nanocrystalline composite coatings have been grown by arc ion plating together with a specimen cooling system. With decreasing substrate temperature, the coatings undergo significant structure evolution. The degree of crystallization first decreases and subsequently increases as confirmed by X-ray diffraction. The cluster size first decreases and then remains constant as confirmed by transmission electron microscopy. The effect of substrate temperature on the evolution of the structure has been studied as a result of a competition between nucleation thermodynamics and kinetics of crystalline growth. With decreasing the substrate temperature, the microhardness and the critical load of the composite coatings firstly increased, and then remained almost constant. And the saturation magnetization revealed the opposite trend over the same range. The essence of these phenomena was ascribed to the microstructural variations caused by the decrease of the substrate temperature.

关键词： Amorphous/nanocrystalline composite coatings Arc ion plating Thermodynamics Kinetics Microhardness Critical load

Hybrid Beamforming Design and Signal Processing with Fully-Connected Architecture for mmWave Integrated Sensing and Communications

在线全文

学校读者我要写书评

暂无评论

Journal of Communications and Information Networks 2024年第2期9卷 151-161页

作者： Hongyu Li jun gong Wenchi Cheng The 54th Research Institute of China Electronics Technology Group Corporation Shijiazhuang 050080China State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an 710071China

Millimeter-wave (mmWave) is capable of achieving gigabit/second communication capacity and centimeter-level sensing accuracy and has become one of the main frequency bands for integrated sensing and communications (ISAC) research. Hybrid beamforming techniques have attracted much attention for solving the high path loss of mmWave and further reducing the hardware cost of the system. However, the related studies based on multicarrier and fully-connected hybrid architectures are still limited. For this reason,this paper investigates the orthogonal frequency division multiplexing (OFDM) based mmWave fully-connected hybrid architecture ISAC system to form a stable communication beam and dynamically varying sensing beam. In order to realize the aforementioned multifunctional beams, the hybrid beamformer design problem based on weighted error minimization of multicarrier is proposed and solved efficiently using the penalty dual decomposition (PDD) algorithm. Meanwhile, based on the echo model, the multicarrier multiple signal classification (MUSIC) algorithm for target angle of arrival estimation and the two-dimensional discrete Fourier transform(2D-DFT)algorithm for distance and velocity estimation are proposed, respectively. Numerical simulation results show that by adjusting the weighting factor,a flexible trade-off can be formed between the communication spectrum efficiency and the sensing accuracy error.

关键词： integrated sensing and communications hybrid beamforming fully-connected architecture millimeter-wave

Diversity and distribution of bacterioplankton in the coastal upwelling waters off Hainan Island,China

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

Acta Oceanologica Sinica 2022年第3期41卷 76-85页

作者： Fahui gong Qixing Ji Guihao Li Kedong Yin jun gong School of Marine Sciences Sun Yat-Sen UniversityZhuhai 519082China Key Laboratory of Marine Resources and Coastal Engineering in Guangdong Province Guangzhou 510006China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China

The diversity,community composition and 16 S rRNA gene abundance of bacterioplankton along a transect across an upwelling area off the eastern coast of Hainan Island(the Qiongdong upwelling)were investigated in August of 2016 using high throughput sequencing and quantitative PCR assay of 16 S rRNA *** with the offshore stations,the inner-shelf stations had higher bacterial gene abundance(up to 3 fold)and operational taxonomic unit richness,a result of the influence of upwelled and fresher ***,a majority of the reads were affiliated with Gammaproteobacteria(11%-74%)and Alphaproteobacteria(14%-43%).The structure of the bacterial community was significantly affected by salinity,dissolved oxygen,NO_(3)^(-) and NH_(4)^(+),which also defined the physicochemical features of the upwelled ***,the relative abundances and gene abundances of Rhodobacteraceae,SAR86,Cyanobacteria and Bacteroidetes in eutrophic zone decreased from the inner to outer shelves and slope,whereas Alteromonas,Vibrio and Oceanospirillaceae exhibited an opposite *** study stresses the riverine influence on the oceanographic condition and spatial variability of bacterioplankton diversity and distribution in the Qiongdong upwelling.

关键词： 16S rRNA bacterioplankton coastal upwelling Hainan Island

Bogdanov-Takens Bifurcation in a Leslie-Gower Predator-prey Model with Prey Harvesting

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2014年第1期30卷 239-244页

作者： Yi-jun gong Ji-cai HUANG School of Mathematics and Statistics Central China Normal University

This paper discuss the cusp bifurcation of codimension 2 （i.e. Bogdanov-Takens bifurcation） in a Leslie^Gower predator-prey model with prey harvesting, which was not revealed by Zhu and Lan [Phase portraits, Hopf bifurcation and limit cycles of Leslie-Gower predator-prey systems with harvesting rates, Discrete and Continuous Dynamical Systems Series B. 14（1）（2010）, 289-306]. It is shown that there are different parameter values for which the model has a limit cycle or a homoclinic loop.

关键词： Leslie-Gower predator-prey model Bogdanov-Takens bifurcation limit cycle homoclinic loop

Combined heuristics for determining order quantity under time-varying demands

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2008年第1期19卷 99-111页

作者： Tang Jiafu Pan Zhendong gong jun Liu Shixin Dept. of Systems Engineering Key Lab of Integrated Automation of Process Industry of MOE Northeastern Univ. Shenyang 110004 P. R. China

The time-varying demands for a certain period are often assumed to be less than the basic economic order quantity （EOQ） so that total replenishment quantity rather than economic order quantity is normally considered by most of the heuristics. This acticle focuses on a combined heuristics method for determining order quantity under generalized time-varying demands. The independent policy （IP）, abnormal independent policy （AIP） and dependent policies are studied and compared. Using the concepts of normal/abnormal periods and the properties of dependent policies, a dependent policy-based heuristics （DPH） is proposed for solving the order quantity problems with a kind of time-varying demands pattern under which the first period is normal. By merging the Silver-Meal （S-M） heuristics and the dependent policy-based heuristics （DPH）, a combined heuristics （DPH/S-M） is developed for solving order quantity problems with generalized time-varying demands. The experimentation shows that （1） for the problem with one normal period, no matter which position the normal period stands, the DPH/S-M could not guarantee better than the S-M heuristics, however it is superior to the S-M heuristics in the case that the demands in the abnormal periods are in descending order, and （2） The DPH/S-M is superior to the S-M heuristics for problems with more than one normal period, and the more the number of normal periods, the greater the improvements.

关键词： heuristics EOQ time-varying demands inventory management

Preparation of SiC Fiber Reinforced Nickel Matrix Composite

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2012年第3期28卷 234-240页

作者： Lu Zhang Nanlin Shi jun gong Chao Sunt Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

A method of preparing continuous（Al＋Al2O3）-coated SiC fiber reinforced nickel matrix composite was presented,in which the diffusion between SiC fiber and nickel matrix could be *** sputtering is used to deposit Ni coating on the surface of the（Al＋Al2O3）-coated SiC fiber in preparation of the precursor *** is shown that the deposited Ni coating combines well with the（Al＋Al2O3） coating and has little negative effect on the tensile strength of（Al＋Al2O3）-coated SiC ***-state diffusion bonding process is employed to prepare the（Al＋Al2O3）-coated SiC fiber reinforced nickel matrix with 37% fibers in *** solid-state diffusion bonding process is optimized and the optimum parameters are temperature of 870,pressure of 50 MPa and holding time of 2 *** this condition,the precursor wires can diffuse well,composite of full density can be formed and the（Al＋Al2O3） coating is effective to restrict the reaction between SiC fiber and nickel matrix.

关键词： SiC fiber Composite Diffusion barrier layer Precursor wire

Interfacial Interaction in Coated Carbon Fibre Reinforced Aluminous Mg-based Composites

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2008年第6期24卷 936-940页

作者： Kun LI Nanlin SHI jun gong Chao SUN Division of Surface Engineering of Materials Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Four kinds of Mg alloys reinforced with carbon fibres were fabricated by a gas pressure infiltration technique. The fibres were pre-coated a SiO2 layer prior to fabrication. DifFerent microstructures and interactions in the fibre-matrix interface of these composites were observed by transmission electron microscopy （TEM）. The results showed that the interracial interaction strongly depended on the content of Al in the Mg-based matrices. The microstructure of the interface could then be controlled by adjusting the Al content of the Mgbased matrix. In addition, fibres extracted from different Mg-based matrix all had some degradation owing to the interracial reaction and the fibre-matrix interdiffusion.

关键词： Carbon fibre SiO2 coating Microstructure Interface

Wrinkle analysis of a space planar film reflect-array

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第1期12卷 24-32页

作者： Wei-wei XIAO Wu-jun CHEN gong-yi FU Space Structures Research Centre Shanghai Jiao Tong University Shanghai 200030 China

The presence of wrinkles in a membrane is the main factor that induces surface errors on space planar film reflect-arrays. Based on the commercial finite element (FE) package ABAQUS, a numerical procedure for membrane wrinkle analysis was set up, and used to analyze a square planar film reflect-array under pure shear force to evaluate its induced wrinkle characteristics. First, the effect of shear force on the wrinkle pattern of the array was studied and validated by experiment. Second, the effect of prestress was studied. When the prestress increases, the quantity of the wrinkles increases, and the amplitude of the wrinkles decreases. Third, the influence of the boundary conditions was investigated. A frame side edge structure has a relatively smooth surface, but also relatively high stress. Finally, the behavior of a joint seam was analyzed. The results indicate that a joint band has a significant influence on the wrinkle pattern of the membrane.

关键词： Space planar film reflect-array Wrinkle analysis Joint seam