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Simulation of Fracture Process of Lightweight Aggregate Concrete Based on Digital Image Processing Technology

Computers, Materials & Continua 2024年第6期79卷 4169-4195页

作者： Safwan Al-sayed xi Wang Yijiang peng Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing100124China

The mechanical properties and failure mechanism of lightweight aggregate concrete(LWAC)is a hot topic in the engineering field,and the relationship between its microstructure and macroscopic mechanical properties is also a frontier research topic in the academic *** this study,the image processing technology is used to establish a micro-structure model of lightweight aggregate *** the information extraction and processing of the section image of actual light aggregate concrete specimens,the mesostructural model of light aggregate concrete with real aggregate characteristics is *** numerical simulation of uniaxial tensile test,uniaxial compression test and three-point bending test of lightweight aggregate concrete are carried out using a new finite element method-the base force element method ***,the image processing technology is used to produce beam specimens,uniaxial compression specimens and uniaxial tensile specimens of light aggregate concrete,which can better simulate the aggregate shape and random distribution of real light aggregate ***,the three-point bending test is numerically ***,the uniaxial compression specimen generated by image processing technology is numerically ***,the uniaxial tensile specimen generated by image processing technology is numerically *** mechanical behavior and damage mode of the specimen during loading were *** results of numerical simulation are compared and analyzed with those of relevant *** feasibility and correctness of the micromodel established in this study for analyzing the micromechanics of lightweight aggregate concrete materials are *** processing technology has a broad application prospect in the field of concrete mesoscopic damage analysis.

关键词： Digital image processing lightweight aggregate concrete mesoscopic model numerical simulation fracture analysis bending beams

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Fault Identification for Shear-Type Structures Using Low-Frequency Vibration Modes

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2769-2791页

作者： Cuihong Li Qiuwei Yang xi peng School of Civil Engineering Shaoxing UniversityShaoxing312000China School of Civil and Transportation Engineering Ningbo University of TechnologyNingbo315211China Engineering Research Center of Industrial Construction in Civil Engineering of Zhejiang Ningbo University of TechnologyNingbo315211China

Shear-type structures are common structural forms in industrial and civil buildings,such as concrete and steel frame *** diagnosis of shear-type structures is an important topic to ensure the normal use of *** main drawback of existing damage assessment methods is that they require accurate structural finite element models for damage ***,for many shear-type structures,it is difficult to obtain accurate *** order to avoid finite elementmodeling,amodel-freemethod for diagnosing shear structure defects is developed in this *** method only needs to measure a few low-order vibration modes of the *** proposed defect diagnosis method is divided into two *** the first stage,the location of defects in the structure is determined based on the difference between the virtual displacements derived from the dynamic flexibility matrices before and after *** the second stage,damage severity is evaluated based on an improved frequency sensitivity *** innovations of this method lie in two *** first innovation is the development of a virtual displacement difference method for determining the location of damage in the shear *** second is to improve the existing frequency sensitivity equation to calculate the damage degree without constructing the finite *** has been verified on a numerical example of a 22-story shear frame structure and an experimental example of a three-story steel shear *** on numerical analysis and experimental data validation,it is shown that this method only needs to use the low-order modes of structural vibration to diagnose the defect location and damage degree,and does not require finite element *** proposed method should be a very simple and practical defect diagnosis technique in engineering practice.

关键词： Fault diagnosis shear steel structure vibration mode dynamic flexibility frequency sensitivity

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Gamma Approximation Based Multi-Antenna Covert Communication Detection

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CHINA COMMUNICATIONS 2024年第9期21卷 90-97页

作者： Wan, pengwu Chen, Dongrui Wang, Danyang Hui, xi peng, Kang xian Univ Posts & Telecommun Sch Commun & Informat Engn Xian 710121 Peoples R China xian Univ Posts & Telecommun Sch Artificial Intelligence Xian 710121 Peoples R China xidian Univ Sch Telecommun Engn Key Lab Integrated Serv Networks Xian 710071 Peoples R China

Covert communication technology makes wireless communication more secure, but it also provides more opportunities for illegal users to transmit harmful information. In order to detect the illegal covert communication of the lawbreakers in real time for subsequent processing, this paper proposes a Gamma approximation-based detection method for multi-antenna covert communication systems. Specifically, the Gamma approximation property is used to calculate the miss detection rate and false alarm rate of the monitor firstly. Then the optimization problem to minimize the sum of the missed detection rate and the false alarm rate is proposed. The optimal detection threshold and the minimum error detection probability are solved according to the properties of the Lambert W function. Finally, simulation results are given to demonstrate the effectiveness of the proposed method.

关键词： covert communication detection Gamma approximation Lambert W function multi-antenna technique

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Experimental investigation on using CO_(2)/H_(2)O emulsion with high water cut in enhanced oil recovery

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Petroleum Science 2024年第2期21卷 974-986页

作者： xi-Dao Wu peng xiao Bei Liu Guang-Jin Chen Jian-Hua Pang State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Ocean Intelligence Technology Center Shenzhen Institute of Guangdong Ocean UniversityShenzhen518120GuangdongChina

CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility ***,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fraction),while CO_(2) emulsion with high water cut has been rarely *** this paper,we carried out a comprehensive experimental study of using high water cut CO_(2)/H_(2)O emulsion for enhancing oil ***,a nonionic surfactant,alkyl glycosides(APG),was selected to stabilize CO_(2)/H_(2)O emulsion,and the corresponding morphology and stability were evaluated with a transparent PVT ***,plugging capacity and apparent viscosity of CO_(2)/H_(2)O emulsion were measured systematically by a sand pack displacement apparatus connected with a 1.95-m long capillary ***,a high water cut(40 vol%) CO_(2)/H_(2)O emulsion was selected for flooding experiments in a long sand pack and a core sample,and the oil recovery,the rate of oil recovery,and the pressure gradients were *** results indicated that APG had a good performance on emulsifying and stabilizing CO_(2) *** inversion from H_(2)O/CO_(2) emulsion to CO_(2)/H_(2)O emulsion with the increase in water cut was ***_(2)/H_(2)O emulsions with lower water cuts presented higher apparent viscosity,while the optimal plugging capacity of CO_(2)/H_(2)O emulsion occurred at a certain water ***,the displacement using CO_(2)/H_(2)O emulsion provided 18.98% and 13.36% additional oil recovery than that using pure CO_(2) in long sand pack and core tests,*** work may provide guidelines for EOR using CO_(2) emulsions with high water cut.

关键词： CO_(2)/H_(2)O emulsion High water cut CO_(2) mobility control Enhanced oil recovery

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A unified Minorization-Maximization approach for estimation of general mixture models

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 343-362页

作者： HUAng xi-fen LIU Deng-ge ZHOU Yun-peng ZHU Fei School of Mathematics Yunnan Normal UniversityKunming 650092China Department of Statistics and Actuarial Science The University of Hong KongHong KongChina

The mixed distribution model is often used to extract information from heteroge-neous data and perform modeling *** the density function of mixed distribution is complicated or the variable dimension is high,it usually brings challenges to the parameter es-timation of the mixed distribution *** application of MM algorithm can avoid complex expectation calculations,and can also solve the problem of high-dimensional optimization by decomposing the objective *** this paper,MM algorithm is applied to the parameter estimation problem of mixed distribution *** method of assembly and decomposition is used to construct the substitute function with separable parameters,which avoids the problems of complex expectation calculations and the inversion of high-dimensional matrices.

关键词： MM algorithm mixed distribution model parameter estimation assembly decomposition tech-nology parameter separation

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Rational cathode configuration with bilayer membranes to engineer current-collector-free high-areal-sulfur lithium-sulfur batteries

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Nano Research 2024年第6期17卷 5224-5232页

作者： Jianmei Han Hua Zhang peng Wang Ning Song Xuguang An Baojuan xi Shenglin xi.ng College of Chemistry and Chemical Engineering Taishan UniversityTai’an 271021China Key Laboratory of the Colloid and Interface Chemistry Ministry of Educationand School of Chemistry and Chemical EngineeringShandong UniversityJinan 250100China School of Mechanical Engineering Chengdu UniversityChengdu 610106China

The application of light-weight current collectors is preferred because of the increased energy density of the *** it in mind,the cathode is designed with self-made paperlike memberane as current collector coupled with another interlayer to enable the high-energy-density lithium-sulfur *** a facile and green step-by-step methodology,the hybrid membrane is finalized successfully,consisting of reduced graphene oxide sheets covering paper-derived carbon(GPC)bearing Fe@Fe2O3 and Fe1−xS@Fe2O3 core-shell nanoparticles(FeFeO/FeSFeO@GPC).The film works as the current collector and interlayer simultaneously considering the porous and conductive *** demonstrated by the electrochemical testing,the FeFeO/FeSFeO@GPC hybrid cell exhibits attractive cycling stability and superior rate *** cell configuration and structural/composition merits of FeFeO/FeSFeO@GPC film facilitate the faster reaction kinetics,conducive to the improvement of capacity *** view of the effective cathode design,the areal sulfur loading is increased to 10.46 mg·cm^(−2)and a reversible capacity of 6.67 mAh·cm^(−2)can be retained after 60 cycles at 0.1 C.

关键词： light-weight self-made current collector core-shell high-areal-sulfur lithium-sulfur batteries

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Chemical Scissors Tailored Nano‑Tellurium with High‑Entropy Morphology for Efficient Foam‑Hydrogel‑Based Solar Photothermal Evaporators

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Nano-Micro Letters 2024年第3期16卷 149-168页

作者： Chenyang xing Zihao Li Ziao Wang Shaohui Zhang Zhongjian xie xi Zhu Zhengchun peng State Key Laboratory of Radio FrequencyHeterogeneous Integration Shenzhen UniversityShenzhen 518060People’s Republic of China Center for Stretchable Electronics and NanoSensors College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060People’s Republic of China School of Science and Engineering The Chinese University of Hong KongShenzhenShenzhen 518172People’s Republic of China Institute of Pediatrics Shenzhen Children’s HospitalShenzhen 518038GuangdongPeople’s Republic of China International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060People’s Republic of China

The development of tellurium(Te)-based semiconductor nanomaterials for efficient light-to-heat conversion may offer an effective means of harvesting sunlight to address global energy ***,the nanosized Te(nano-Te)materials reported to date suffer from a series of drawbacks,including limited light absorption and a lack of surface ***,we report the preparation of nano-Te by electrochemical exfoliation using an electrolyzable room-temperature ionic ***,cations,and their corresponding electrolytic products acting as chemical scissors can precisely intercalate and functionalize bulk *** resulting nano-Te has high morphological entropy,rich surface functional groups,and broad light *** also constructed foam hydrogels based on poly(vinyl alcohol)/nano-Te,which achieved an evaporation rate and energy efficiency of 4.11 kg m^(−2)h^(−1)and 128%,respectively,under 1 sun ***,the evaporation rate was maintained in the range 2.5-3.0 kg m^(−2)h^(−1)outdoors under 0.5-1.0 sun,providing highly efficient evaporation under low light conditions.

关键词： Tellurium High entropy Electrochemical modification Solar absorption Evaporation rate

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Responses of arbuscular mycorrhizal fungi to straw return and nitrogen fertilizer reduction in a rainfed maize field

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Pedosphere 2024年第2期34卷 351-360页

作者： Zhenling peng Hao xi Lin MAO Huyuan FEng Jianjun ZHAng Yongjun LIU State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems College of EcologyLanzhou UniversityLanzhou 730000China College of Life Sciences Northwest Normal UniversityLanzhou 730070China School of Life Sciences Lanzhou UniversityLanzhou 730000China Dryland Agriculture Institute Gansu Academy of Agricultural SciencesLanzhou 730070China

Straw return can be used to reduce fertilizer input and improve agricultural sustainability and soil ***,how straw return and reduced fertilizer application affect beneficial soil microbes,particularly arbuscular mycorrhizal fungi(AMF),remains poorly ***,we conducted a five-year field experiment in a rainfed maize field on the Loess Plateau of northwestern *** tested four treatments with straw return combined with four nitrogen(N)application rates,i.e.,100%,80%,60%,and 0%of the common N application rate(225 kg N ha^(-1)year^(-1))in this region,and two reference treatments(full or no N application),with three replicates for each *** colonization was quantified and AMF communities colonizing maize roots were characterized using Illumina *** virtual taxa(VTs)of AMF were identified in root samples,among which VT113(related to Rhizophagus fasciculatus)and VT156(related to Dominikia gansuensis)were the predominant *** root length colonization and AMF VT richness were sensitive to N fertilization,but not to straw return;furthermore,both gradually increased with decreasing N application *** VT composition of the AMF community was also affected by N fertilization,but not by straw return,and the community variation could be well explained by soil available N and phosphorus ***,60%,80%,and full N fertilization produced similar maize ***,our study revealed the response patterns of AMF to straw return and N fertilizer reduction and showed that straw return combined with N fertilizer reduction may be a promising practice to maintain mycorrhizal symbiosis concomitantly with crop productivity.

关键词： agricultural sustainability crop productivity mycorrhizal colonization mycorrhizal symbiosis root length colonization virtual taxon

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Working condition recognition of sucker rod pumping system based on 4-segment time-frequency signature matrix and deep learning

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Petroleum Science 2024年第1期21卷 641-653页

作者： Yun-peng He Hai-Bo Cheng peng Zeng Chuan-Zhi Zang Qing-Wei Dong Guang-xi Wan xiao-Ting Dong State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016LiaoningChina Key Laboratory of Networked Control Systems Chinese Academy of SciencesShenyang 110016LiaoningChina Institutes for Robotics and Intelligent Manufacturing Chinese Academy of SciencesShenyang 110169LiaoningChina University of Chinese Academy of Sciences Beijing100049China School of Artifcial Intelligence Shenyang University of TechnologyShenyang 110870LiaoningChina

High-precision and real-time diagnosis of sucker rod pumping system(SRPS)is important for quickly mastering oil well *** learning-based method for classifying the dynamometer card(DC)of oil wells is an efficient diagnosis ***,the input of the DC as a two-dimensional image into the deep learning framework suffers from low feature utilization and high computational ***,different SRPSs in an oil field have various system parameters,and the same SRPS generates different DCs at different ***,there is heterogeneity in field data,which can dramatically impair the diagnostic *** solve the above problems,a working condition recognition method based on 4-segment time-frequency signature matrix(4S-TFSM)and deep learning is presented in this ***,the 4-segment time-frequency signature(4S-TFS)method that can reduce the computing power requirements is proposed for feature extraction of DC ***,the 4S-TFSM is constructed by relative normalization and matrix calculation to synthesize the features of multiple data and solve the problem of data ***,a convolutional neural network(CNN),one of the deep learning frameworks,is used to determine the functioning conditions based on the *** on field data verify that the proposed diagnostic method based on 4S-TFSM and CNN(4S-TFSM-CNN)can significantly improve the accuracy of working condition recognition with lower computational *** the best of our knowledge,this is the first work to discuss the effect of data heterogeneity on the working condition recognition performance of SRPS.

关键词： Sucker-rod pumping system Dynamometer card Working condition recognition Deep learning Time-frequency signature Time-frequency signature matrix

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Research on a multi‑dimensional image information fusion algorithm based on NSCT transform

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Frontiers of Optoelectronics 2024年第1期17卷 29-44页

作者： Yuxi.ng Su xi Liang Danhua Cao Zhenyu Yang Yuanlong peng Ming Zhao School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China State Grid Information and Telecommunication Branch Beijing 100761China

Traditional inspection cameras determine targets and detect defects by capturing images of their light intensity,but in complex environments,the accuracy of inspection may *** based on polarization of light can characterize various features of a material,such as the roughness,texture,and refractive index,thus improving classification and recognition of *** paper uses a method based on noise template threshold matching to denoise and preprocess polarized *** also reports on design of an image fusion algorithm,based on NSCT transform,to fuse light intensity images and polarized *** results show that the fused image improves both subjective and objective evaluation indicators,relative to the source image,and can better preserve edge information and help to improve the accuracy of target *** study provides a reference for the comprehensive application of multi-dimensional optical information in power inspection.

关键词： Power inspection Object detection Polarization imaging Image fusion Image denoising

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