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Shear band evolution and acoustic emission characteristics of sandstone containing non-persistent flaws

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 497-513页

作者： Shuting Miao Peng-zhi pan Chuanqing Zhang Lei Huo State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China CASIC Research Institute of Intelligent Decision Engineering Wuhan430040China

Direct shear tests were conducted on sandstone specimens under different constant normal stresses to study the coalescence of cracks between non-persistent flaws and the shear sliding characteristics of the shear-formed *** image correlation and acoustic emission(AE)techniques were used to monitor the evolution of shear bands at the rock bridge area and microcracking *** experimental results revealed that the shear stresses corresponding to the peak and sub-peak in the stressdisplacement curve are significantly affected by the normal *** localization bands emerged at both the tip of joints and the rock bridge,and their extension and interaction near the peak stress caused a surge in the AE hit rate and a significant decrease in the AE b *** and curvilinear strain bands were detected at low normal stress,while high normal stress generally led to more microcracking events and longer coplanar cracks at the rock bridge ***,an increase in normal stress resulted in a higher AE count rate and more energetic AE events during friction sliding along the shearformed *** was observed that the elastic energy released during the crack coalescence at the prepeak stage was much greater than that released during friction sliding at the post-peak *** than 75%of AE events were located in the low-frequency band(0e100 kHz),and this proportion continued to rise with increasing normal ***,more AE events of low AF value and high RA value were observed in specimens subjected to high normal stress,indicating that greater normal stress led to more microcracks of shear nature.

关键词： Shear band evolution Acoustic emission(AE) Crack coalescence Normal stress Shear sliding

Sparse antenna array design methodologies:A review

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Journal of Electronic Science and Technology 2024年第3期22卷 1-15页

作者： pan Wu Yan-Hui Liu zhi-Qin Zhao Qing-Huo Liu School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China Eastern Institute of Technology Ningbo315200China

Designing a sparse array with reduced transmit/receive modules(TRMs)is vital for some applications where the antenna system’s size,weight,allowed operating space,and cost are *** arrays exhibit distinct architectures,roughly classified into three categories:Thinned arrays,nonuniformly spaced arrays,and clustered *** numerous advanced synthesis methods have been presented for the three types of sparse arrays in recent years,a comprehensive review of the latest development in sparse array synthesis is *** work aims to fill this gap by thoroughly summarizing these *** study includes synthesis examples to facilitate a comparative analysis of different techniques in terms of both accuracy and ***,this review is intended to assist researchers and engineers in related fields,offering a clear understanding of the development and distinctions among sparse array synthesis techniques.

关键词： Clustered array Nonuniformly spaced array Sparse antenna array Synthesis method Thinned array

Recent advances in Ir/Ru-based perovskite electrocatalysts for oxygen evolution reaction

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Rare Metals 2024年第7期43卷 2891-2912页

作者： zhi-Qi Jiang Cheng-Zhen Fan Jun-Yu pan Li Shao Hao Chen Erum Pervaiz Yan Dong Tong-Zhou Wang Xue-Rong Zheng Ji-Hong Li Yi-da Deng School of Materials Science and Engineering Hainan UniversityHaikou570228Chin Department of Chemical Engineering School of Chemical and Materials Engineering(SCME)National University of Sciences&Technology(NUST)Islamabad 44000Pakistan Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin 300071Chin

Oxygen evolution reaction(OER)is a kinetically harsh four-electron anode reaction that requires a large overpotential to provide current and is of great importance in renewable electrochemical ***/Rubased perovskite oxides hold great significance for application as OER electrocatalysts,due to that their multimetal-oxide forms can reduce the use of noble metals,and their compositional tunability can modulate the electronic structure and optimize OER ***,high operating potentials and corrosive environments pose a serious challenge to the development of durable Ir-based and Ru-based perovskite *** efforts have been dedicated to improving the Ir/Ru-based perovskite activity to enhance the efficiency;however,progress in improving the durability of Ir/Ru-based perovskite electrocatalysts has been rather *** this review,the recent research progress of Ir/Ru-based perovskites is reviewed from the perspective of heteroatom doping,structural modulation,and formation of *** dissolution mechanism studies of Ir/Ru and experimental attempts to improve the durability of Ir/Ru-based perovskite electrocatalysts are *** and outlooks for further developing Ru-and Irbased perovskite oxygen electrocatalysts are also presented.

关键词： Oxygen evolution reaction Ir/Ru-based perovskites Stability Electrocatalysts

A novel indirect optical method for rock stress measurement using micro- deformation fi eld analysis

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JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING 2024年第9期16卷 3616-3628页

作者： Feng, Yujie pan, Peng-zhi Wang, Zhaofeng Liu, Xufeng Miao, Shuting Chinese Acad Sci Inst Rock & Soil Mech State Key Lab Geomech & Geotech Engn Wuhan 430071 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

Stress measurement plays a crucial role in geomechanics and rock engineering, especially for the design and construction of large-scale rock projects. This paper presents a novel method, based on the traditional stress relief approach, for indirectly measuring rock stress using optical techniques. The proposed method allows for the acquisition of full-field strain evolution on the borehole's inner wall before and after disturbance, facilitating the determination of three-dimensional (3D) stress information at multiple points within a single borehole. The study focuses on presenting the method's theoretical framework, laboratory validation results, and equipment design conception. The theoretical framework comprises three key components: the optical imaging method of the borehole wall, the digital image correlation (DIC) method, and the stress calculation procedure. Laboratory validation tests investigate strain field distribution on the borehole wall under varying stress conditions, with stress results derived from DIC strain data. Remarkably, the optical method demonstrates better measurement accuracy during the unloading stage compared to conventional strain gauge methods. At relatively high stress levels, the optical method demonstrates a relative error of less than 7% and an absolute error within 0.5 MPa. Furthermore, a comparative analysis between the optical method and the conventional contact resistance strain gauge method highlights the optical method's enhanced accuracy and stability, particularly during the unloading stage. The proposed optical stress measurement device represents a pioneering effort in the application of DIC technology to rock engineering, highlighting its potential to advance stress measurement techniques in the field. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-n

关键词： Rock stress measurement Optical technology Digital image correlation (DIC) technology Micro-deformation field IN-SITU STRESS DIGITAL-IMAGE-CORRELATION BOREHOLE

Multi-scale data joint inversion of minerals and porosity in altered igneous reservoirs—A case study in the South China Sea

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Petroleum Science 2024年第1期21卷 206-220页

作者： Xin-Ru Wang Bao-zhi pan Yu-Hang Guo Qing-Hui Wang Yao Guan College of Geo-exploration Science and Technology Jilin UniversityChangchun130046JilinChina Research Institute CNOOC Ltd.-ShenzhenShenzhen518000GuangdongChina

There are abundant igneous gas reservoirs in the South China Sea with significant value of research,and lithology classification,mineral analysis and porosity inversion are important links in reservoir ***,affected by the diverse lithology,complicated mineral and widespread alteration,conventional logging lithology classification and mineral inversion become considerably *** the same time,owing to the limitation of the wireline log response equation,the quantity and accuracy of minerals can hardly meet the exploration requirements of igneous *** overcome those issues,this study takes the South China Sea as an example,and combines multi-scale data such as micro rock slices,petrophysical experiments,wireline log and element cutting log to establish a set of joint inversion methods for minerals and porosity of altered igneous ***,we define the lithology and mineral characteristics through core slices and mineral data,and establish an igneous multi-mineral volumetric *** we determine element cutting log correction method based on core element data,and combine wireline log and corrected element cutting log to perform the lithology classification and joint inversion of minerals and ***,it is always difficult to determine the elemental eigenvalues of different minerals in *** paper uses multiple linear regression methods to solve this ***,an integrated inversion technique for altered igneous formations was *** results show that the corrected element cutting log are in good agreement with the core element data,and the mineral and porosity results obtained from the joint inversion based on the wireline log and corrected element cutting log are also in good agreement with the core data from X-ray *** results demonstrate that the inversion technique is applicable and this study provides a new direction for the mineral inversion research of altered igneous formation

关键词： Joint inversion Altered igneous rock Element correction method Lithology identification Multi mineral volume model

Preparation and Structure-Property Regulation Mechanism of Reversible Thermochromic Polydiacetylene

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Chinese Journal of Polymer Science 2024年第8期42卷 1111-1121页

作者： zhi-Qing Ge Shuo Yan Zu-Xiong pan Shan Lei Xuan-zhi Mao Chu Zhao Mo-Zhen Wang Xue-Wu Ge Key Laboratory of Precision and Intelligent Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China Marshall Laboratory of Biomedical Engineering International Cancer CenterLaboratory of Evolutionary Theranostics(LET)School of Biomedical EngineeringShenzhen University Medical SchoolShenzhen UniversityShenzhen 518055China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

The thermochromic mechanism and the structure-property regulation principle of reversible thermochromic polydiacetylene(Pda)materials have always been a challenging *** this work,a series of diacetylene monomers(m-PCda)containing phenyl and amide or carboxyl groups were synthesized from 10,12-pentacosadiynoic acid(PCda)through the esterification or amidation *** effects of the number and the distribution of the functional groups in m-PCda molecules on their solid-state polymerization capability,and the thermochromic mechanism of their corresponding polymers(m-Pda)were investigated and discussed in *** results show that the m-PCda monomers containing both benzene ring and groups that can form hydrogen bonding interactions have strong intermolecular interaction,and are easy to carry out the solid phase polymerization under 254-nm UV irradiation to obtain the corresponding new thermochromic m-Pda *** thermochromic behavior of m-Pda depends on its melting *** initial color-change temperature(blue to red)is determined by the onset melting tem perature,and the temperature range in which reversible color recovery can be achieved by repeat heating-cooling treatment is determined by its melting *** to the proposed thermochromic mechanism of Pda,various new Pda materials with precise thermochromic temperatu res and reversible thermochromic temperature ra nges can be designed and synthesized through the appropriate introduction of benzene ring and groups that can form hydrogen bonding interactions into the molecular structure of linear diacetylene *** work provides a perspective to the precise molecular structure design and the property regulation of the reversible thermochromic Pda materials.

关键词： Polydiacetylene Thermochromism Hydrogen bonding Chemical modification

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有向图扩展边集数组存储结构的实现

计算机工程 2009年第22期35卷 38-39,43页

作者：潘大志刘志斌西华师范大学数学与信息学院南充637000 西南石油大学理学院成都610041

对有向图边集数组存储结构进行修改和扩展,在其基础上利用栈机制实现有向图操作的基本算法:生成算法和拓扑排序算法。该扩展结构能克服边集数组存储结构不便于图操作的缺点,通过空间的重复使用,有效地节约存储空间,通过静态存储空间实... 详细信息

对有向图边集数组存储结构进行修改和扩展,在其基础上利用栈机制实现有向图操作的基本算法:生成算法和拓扑排序算法。该扩展结构能克服边集数组存储结构不便于图操作的缺点,通过空间的重复使用,有效地节约存储空间,通过静态存储空间实现图的表示,提高算法的稳定性。

关键词：有向图边集数组扩展边集数组静态链栈拓扑排序

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递推算法在扩展约瑟夫环问题中的应用

计算机工程与应用 2010年第34期46卷 62-63,106页

作者：潘大志刘志斌西南石油大学理学院成都610500 西华师范大学数学与信息学院四川南充637000

对约瑟夫环问题进行扩展,并将递推算法和静态链表的思想用于解决扩展问题。得到了扩展问题的递推表达式,给出了求解扩展问题的算法,其时间复杂度为O(n)。运行实例表明,与常规的模拟算法相比,大大提高了求解问题的速度。

关键词：扩展约瑟夫环问题递推算法模拟算法静态链表

Multi-physical fields distribution in billet during helical electromagnetic stirring:A numerical simulation research

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China Foundry 2024年第1期21卷 51-59页

作者： Dong pan Qing-tao Guo Kai-lun Zhang Fu-zhi Yu Yu-ying Li Yu-bao Xiao State Key Laboratory of Metal Materials for Marine Equipment and Application Anshan 114009LiaoningChina Ansteel Beijing Research Institute Co. Ltd.Beijing 102200China

Electromagnetic stirring is one of the widely applied techniques to modify the quality of casting *** from conventional rotate stirring,the helical stirring is more professional in assisting multi-dimensional flow of molten metal and eliminating solidification *** this study,the single-winding helical stirring(SWHS)was introduced,offering advantages such as smaller volume and lower electromagnetic shielding compared to traditional helical stirring *** a comprehensive numerical simulation,the stirring parameters of SWHS were adjusted to yoke inclination angle of 43°and frequency of 12 *** higher electromagnetic force and flow velocity in drawing direction,as well as the lower temperature gradient induced by the SWHS,are positive factors for homogeneous solidification of *** experimental results on Al-8%Si alloy and 0.4%C-1.1%Mn steel demonstrate that compared to rotate stirring,the SWHS process can induce better billet quality and is more effective in accelerating the equiaxed expansion and reducing element *** SWHS process can enhance the equiaxed ratio of the billet by 58.3%and reduce segregation degree of carbon element by 10.97%.Consequently,SWHS holds great promise as a potential approach for improving the quality of continuous casting billets.

关键词： billet electromagnetic stirring helical solidification element segregation numerical simulation