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Intelligent Reflecting Surface-Aided Secure and Covert Communications

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china Communications 2024年第9期21卷 1-10页

作者： Zhou Xiaobo Jiang Yong Xia Tingting Xia guiyang Shen Tong School of Information and Artificial Intelligence Anhui Agricultural UniversityAnhui 230036China

This work employs intelligent reflecting surface(IRS)to enhance secure and covert communication *** formulate an optimization problem to jointly design both the reflection beamformer at IRS and transmit power at transmitter Alice in order to optimize the achievable secrecy rate at Bob subject to a covertness *** first develop a Dinkelbach-based algorithm to achieve an upper bound performance and a high-quality *** reducing the overhead and computational complexity of the Dinkelbach-based scheme,we further conceive a low-complexity algorithm in which analytical expression for the IRS reflection beamforming is derived at each *** result shows that the devised low-complexity algorithm is able to achieve similar secrecy rate performance as the Dinkelbach-based *** examination also shows that introducing an IRS into the considered system can significantly improve the secure and covert communication performance relative to the scheme without IRS.

关键词： covert communications intelligent reflecting surface physical layer security reflection beamforming

A POSTERIORI ERROR ESTIMATES IN ADINI FINITE ELEMENT FOR EIGENVALUE PROBLEMS

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Journal of Computational Mathematics 2000年第4期18卷 413-418页

作者： Yi-du Yang (department of Mathematics, guizhou Normal university, guiyang, 550001) 贵州师范大学贵州贵阳 550001

In this paper, we discuss a posteriori error estimates of the eigenvalue λ[sub h] given by Adini nonconforming finite element. We give an assymptotically exact error estimator of the λ[sub h]. We prove that the order of convergence of the λ[sub h] is just 2 and the converge from below for sufficiently small h. [ABSTRACT FROM AUTHOR]

关键词： eigenvalue nonconforming finite element error estimate

STRESS-STRAIN FINITE ELEMENT ANALYSIS AND FATIGUE LIFE PREDICTION FOR BOLTED CONNECTIONS

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Chinese Journal of Mechanical Engineering 2002年第1期15卷 75-78页

作者： Wang Ziqin Xie Qingsheng Mechanical Engineering department，guizhou university of Technology，guiyang 550003，china Mechanical Engineering department Guizhou University of Technology Guiyang 550003

A cyclic plasticity model is used into finite element (FE) method to obtainthe details of elastic-plastic stress-strain in the bolts under cyclic axial loading. Two criteriain multiaxial fatigue are employed to predict fatigue lives of bolts. The predicted fatigue livesare in favorable agreement with the experimental results for machined bolts.

关键词： Finite element Fatigue Bolted connection

Hydrothermal synthesis of xonotlite from carbide slag

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Progress in Natural Science:Materials International 2008年第9期18卷 1147-1153页

作者： Jianxin Cao , Fei Liu, Qian Lin, Yu Zhang department of Chemical Engineering, guizhou university, guiyang 550003, china department of Chemical Engineering Guizhou University Guiyang 550003 China

Carbide slag was used as the calcareous materials for the first time to prepare xonotlite via dynamic hydrothermal *** efiects of infiuential factors including difierent calcination temperatures, pretreatment methods of the carbide slag and process param-eters of hydrothermal synthesis on the microstructure and morphology of xonotlite were explored using XRD and SEM *** results indicate that the carbide slag after proper calcination could be used to prepare pure xonotlite;and difierent calcination tem-peratures have little efiect on the crystallinity of synthesized xonotlite, but have great impact on the morphology of secondary *** difierent pretreatment methods of the carbide slag pose great impact on the crystallinity and morphology of secondary particles of *** was also synthesized from pure CaO under the same experimental conditions as that prepared from calcined carbide slag for *** amount of impurities in carbide slag has no efiect on the mechanism of hydrothermal synthesizing xonotlite from carbide slag.

关键词： Hydrothermal synthesis Carbide slag Xonotlite Calcination temperature

OPTIMAL CONTROL OF A CLASS OF DISTRIBUTED PARAMETER DELAY SYSTEMS

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Systems Science and Mathematical Sciences 2000年第1期13卷 31-41页

作者： XIANG Xiao ling (department of Mathematics, guizhou university, guiyang 550025, china) 贵州大学数学系贵州贵阳 550025

***,suchajsthemodynamics,electrodynamics,populationbiology,aregovernedbydifferentialequations,integrodifferentialequationsormor***... 详细信息

***,suchajsthemodynamics,electrodynamics,populationbiology,aregovernedbydifferentialequations,integrodifferentialequationsormor***...

关键词： Analytic semigroup fractional power space time lag optimal control adjoint semigroup necessary conditions.

Recent advances in functional utilisation of environmentally friendly and recyclable high-performance green biocomposites: A review

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Chinese Chemical Letters 2024年第4期35卷 73-85页

作者： guiyang Zheng Xuelian Kang Haoran Ye Wei Fan Christian Sonne Su Shiung Lam Rock Keey Liew Changlei Xia Yang Shi Shengbo Ge Co-Innovation Center of Efficient Processing and Utilization of Forest resources College of Materials Science and EngineeringNanjing Forestry UniversityNanjing 210037China School of Textile Science and Engineering&Key Laboratory of Functional Textile Material and Product of Ministry of Education Xi'an Polytechnic UniversityXi'an 710048China department of Bioscience Arctic Research Centre(ARC)Aarhus UniversityFrederiksborgvej 399PO Box 358DK-4000 RoskildeDenmark Sustainability Cluster School of EngineeringUniversity of Petroleum&Energy StudiesDehradunUttarakhand 248007India Higher Institution Centre of Excellence(HICoE) Institute of Tropical Aquaculture and Fisheries(AKUATROP)Universiti Malaysia Terengganu21030 Kuala NerusTerengganuMalaysia Center for Transdisciplinary Research Saveetha Institute of Medical and Technical SciencesSaveetha UniversityChennai 600072India NV Western PLT Georgetown 10400PenangMalaysia Aerospace Kaitian Environmental Technology Co. Ltd.Changsha 410000China Hunan Hongsen Novel Material Technology Co. Ltd.Yiyang 413407China

Humans have relied on biomass for survival and development since the Stone Age. All aspects of human needs for materials are covered by tools, fuel, and buildings. Nowadays, metals and petroleum-based materials are widely used in highly developed industries. Unfortunately, environmental contamination and the loss of natural resources have led to the reemergence of biomass resources as efficient and sustainable energy sources. Notably, simple and direct applications can no longer meet the demand for functionalization, high performance of materials and construction materials. Therefore, it is imperative to modify biomass and combine its utilisation to produce functionalization and high performance materials. For example, construction materials with superior mechanical properties and water resistance can be produced by reinforcing fibres to facilitate crosslinking. Water-oil separation or adsorption effects of hydrogels and aerogels are determined by the porosity and lightness of biomass, biocomposite conductor is prepared by chimaeric conductive material. Here, we review the approaches that have been taken to devise an environmentally friendly yet fully recyclable and sustainable functionalised biocomposites from biomass and its potential directions for future research.

关键词： Biocomposite Renewable Sustainability Advanced functional material Pollution mitigation

Study of Noble Metal Elements in Lower Cambrian Black Rock Series of guizhou-Hunan Provinces, china

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Journal of Earth Science 1999年第1期18卷 93-96页

作者： Li Shengrong department of Geology and Mineral resources, china university of Geosciences, Beijing 100083 Gao Zhenmin Institute of Geochemistry, Chinese Academy of Sciences, guiyang 550002

Systematic analyses of noble metal elements in the Lower Cambrian black rock series of South china are reported. Correlations of w (Os)/ w (Ir), w (Au)/ w (Ir), w (Ag)/ w (Au), w (Pt+Pd)/ w (Os+Ru+Rh+Ir), relations of noble metal and platinum group element (PGE) distribution patterns reveal that the noble metals are not directly from extraterrestrial materials. Studying the data of 9 aspects, the authors conclude that the noble metals were mainly from ultramafic mafic igneous rocks and their enrichment in black rocks is mainly controlled by hydrothermal fluid.

关键词： black shale Au Ag PGE Lower Cambrian guizhou Hunan provinces china.

Research on the Mode of ASP-based Services Alliance for SME

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武汉理工大学学报 2006年第S3期28卷 805-809页

作者： MEI Yi LIU Dan YANG Wenjie department of Mechanical Manufacturing,guizhou university,guiyang 550003,china, department of Mechanical Manufacturing Guizhou UniversityGuiyang 550003China

More and more small and medium enterprises(SMEs)carry professional information systems into effect by Appli- cation Service Provider(ASP).However,lots of ASP has just single function so that they can’t meet needs for collaborative com- merce among ***,the ASP-based Services Alliance(ASA)is proposed to raise level of information application for *** formation process of ASA is introduced,some key methods supporting ASA formation are presented and the practice of ASA in guizhou province which was developed with the key methods *** can get high quality,low cost online services and the ability of capturing market with allied member collaboratively through ASA.

关键词： ASP service alliance member selection efficiency computation dependability optimization

Study on Method of Fault Vibration Diagnose for Roller Overrunning Clutch

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厦门大学学报（自然科学版） 2002年第S1期41卷 216-217页

作者： LUO Yi-xin 1, DOU Yi-bing 2 (1. department of resources Engineering, Xiangtan Polytechnic Univers ity, Xiangtan 411201,china 2. guizhou university, guiyang 550025, china)

Fault diagnose of the roller overrunning clutch is a headache problem in engineering at home and abroad. This paper introduces a new method to solve the problem by using the wavelet transform to separate fault si gnal and further analyzing the impact frequency. The signal local singularities under the wavelet transform are studied. According to the propagation features of modulus maximums of the fault signal and the noise under the wavelet transfor m different on the scales, and by use of the signal wavelet decomposition-recon struction algorithm, the clutch shell vibration acceleration signal is decompose d, denoised, and *** signal-to-noise of the monitored signal imp roved *** fault characteristic signal on time domain is *** f ault characteristic frequency is picked up. Experiment shows that it is quite effective.

关键词： clutch frequency fault diagnose