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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

The construction of shale rock physics model and brittleness prediction for high-porosity shale gas-bearing reservoir

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Petroleum Science 2020年第3期17卷 658-670页

作者： Xin-peng Pan Guang-zhi zhang Jiao-Jiao Chen School of Geoscience and Info-Physics Central South UniversityChangsha 410082HunanChina School of Geoscience China University of Petroleum(East China)Qingdao 266580ShandongChina

Due to the huge differences between the unconventional shale and conventional sand reservoirs in many aspects such as the types and the characteristics of minerals,matrix pores and fluids,the construction of shale rock physics model is significant for the exploration and development of shale *** make a better characterization of shale gas-bearing reservoirs,we first propose a new but more suitable rock physics model to characterize the *** then use a well A to demonstrate the feasibility and reliability of the proposed rock physics model of shale gas-bearing ***,we propose a new brittleness indicator for the high-porosity and organic-rich shale gas-bearing *** on the parameter analysis using the constructed rock physics model,we finally compare the new brittleness indicator with the commonly used Young’s modulus in the content of quartz and organic matter,the matrix porosity,and the types of filled *** also propose a new shale brittleness index by integrating the proposed new brittleness indicator and the Poisson’s *** on real data sets demonstrate that the new brittleness indicator and index are more sensitive than the commonly used Young’s modulus and brittleness index for the high-porosity and high-brittleness shale gas-bearing reservoirs.

关键词： Shale gas Rock physics model Brittleness prediction

Modeling impact of culture facilities on hydrodynamics and solute transport in marine aquaculture waters of North Yellow Sea

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Water Science and Engineering 2023年第1期16卷 26-35页

作者： Heng-zhi Jiang Yong-peng Ji Ming-liang zhang National Marine Environmental Monitoring Center Dalian 116023China Beijing Jiutian Weather Co. LtdBeijing 100081China School of Ocean Science and Environment Dalian Ocean UniversityDalian 116023China

An increasing number of marine aquaculture facilities have been placed in shallow bays and open sea,which might significantly affect hydrodynamic and solute transport processes in marine aquaculture *** this study,a coupled hydrodynamic and solute transport model was developed with high-resolution schemes in marine aquaculture waters based on depth-averaged shallow water equations.A new expression of drag force was incorporated into the momentum equations to express the resistance of suspended culture *** coupled model was used to simulate the effect of suspended structures on tidal currents and the movement of a contaminant cloud in the marine aquaculture of the North Yellow Sea,*** simulation results showed a low-velocity area appearing inside the aquaculture cage area,with a maximum reduction rate of velocity close to 45%under high-density *** results also showed that tidal currents were sensitive to the density of suspended cages,the length of cages,and the drag coefficients of *** transport processes of pollutants inside aquaculture facilities were inhibited away from the vicinity of the culture cage area because of the diminished tidal ***,the suspended cages significantly affected the transport processes of pollutants in the coastal aquaculture ***,the reduced horizontal velocity significantly decreased the food supply for the aquaculture areas from the surrounding sea.

关键词： Marine aquaculture Suspended cages Numerical simulation Current reduction Solute transport

Azimuthal elastic impedance-based Fourier coefficient variation with angle inversion for fracture weakness

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Petroleum Science 2020年第1期17卷 86-104页

作者： Lin Li Jia-Jia zhang Xin-peng Pan Guang-zhi zhang School of Geosciences China University of Petroleum(East China)Qingdao 266580ShandongChina School of Geoscience and Info-Physics Central South UniversityChangsha 410082HunanChina Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071ShandongChina

Quantitative inversion of fracture weakness plays an important role in fracture *** reservoirs with a set of vertical fractures as horizontal transversely isotropic media,the logarithmic normalized azimuthal elastic impedance(EI)is rewritten in terms of Fourier coefficients(FCs),the 90°ambiguity in the azimuth estimation of the symmetry axis is resolved by judging the sign of the second FC,and we choose the FCs with the highest sensitivity to fracture weakness and present a feasible inversion workflow for fracture weakness,which involves:(1)the inversion for azimuthal EI datasets from observed azimuthal angle gathers;(2)the prediction for the second FCs and azimuth of the symmetry axis from the estimated azimuthal EI datasets;and(3)the estimation of fracture weakness combining the extracted second FCs and azimuth of the symmetry axis iteratively,which is constrained utilizing the Cauchy sparse regularization and the low-frequency regularization in a Bayesian *** on synthetic and field data demonstrate that the 90°ambiguity in the azimuth estimation of the symmetry axis has been removed,and reliable fracture weakness can be obtained when the estimated azimuth of the symmetry axis deviates less than 30°,which can guide the prediction of fractured reservoirs.

关键词： Fracture weakness Azimuth of the symmetry axis Azimuthal Fourier coefficients HTI Azimuthal elastic impedance

Electric field manipulation of magnetic skyrmions

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Rare Metals 2022年第12期41卷 4000-4014页

作者： Ya-Dong Wang zhi-Jian Wei Hao-Ran Tu Chen-Hui zhang zhi-peng Hou Guangdong Provincial Key Laboratory of Optical Information Material and Technology&Institute for Advanced Materials South China Academy of Advanced OptoelectronicsSouth China Normal UniversityGuangzhou 510006China Dongguan University of Technology Dongguan 523808China Physical Science and Engineering Division(PSE) King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia

Magnetic skyrmions are vortex-like swirling spin textures that are promising candidates for carrying information bits in future magnetic memories or logic *** build skyrmionic devices,researchers must electrically manipulate magnetic skyrmions to enable easy integration into modern semiconductor *** operation generally uses a spin-polarized current,which unavoidably causes high energy dissipation and Joule ***,the electric-field strategy is a hopeful alternative for electrically manipulating the skyrmions due to the strategy’s negligible Joule heating and low energy *** this review,we systematically summarize the theoretical and experimental development of the electricalfield manipulation of magnetic skyrmions over the past *** review the following magnetic systems and physical mechanisms:(ⅰ)ultra-thin multilayer films with accumulation and release of interfacial charge,(ⅱ)singlephase multiferroic material with magneto-electric coupling,(ⅲ)ferromagnetic/ferroelectric(FM/FE)multiferroic heterostructure with magneto-elastic ***,we consider future developmental trends in the electric-field manipulation of magnetic skyrmions and other topological magnetic domain structures.

关键词： Magnetic skyrmion Electric field Low energy cost Dzyaloshinskii-Moriya interaction(DMI)

妊高征与血管紧张素原基因M_(235)T分子变异的关系

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实用妇产科杂志 2002年第1期18卷 26-28页

作者：杨岚熊庆彭芝兰周容张林四川大学华西第二医院四川成都610041 华西医科大学法医学院物证教研室四川成都610041

目的 :探讨中国成都地区人群中血管紧张素原 (AGT)基因 M2 35 T分子变异与妊娠高血压综合征 (PIH)的关系。方法 :采用聚合酶链反应及限制性片段长度多态性分析 ,对 6 0例 PIH患者和 6 0例正常孕妇进行 AGT基因 M2 35 T基因型及 T2 35等... 详细信息

目的 :探讨中国成都地区人群中血管紧张素原 (AGT)基因 M2 35 T分子变异与妊娠高血压综合征 (PIH)的关系。方法 :采用聚合酶链反应及限制性片段长度多态性分析 ,对 6 0例 PIH患者和 6 0例正常孕妇进行 AGT基因 M2 35 T基因型及 T2 35等位基因检测。结果 :1在该研究的群体中未发现 AGT基因 2 35 TT型。 2 PIH患者 AGT基因 T2 35等位基因频率 (0 .4 6 )与对照组 (0 .4 3)相比无统计学差异 (P>0 .5 )。结论 :1AGT基因 M2 35 T分子变异与所研究人群 PIH的发生无关。 2 AGT基因 M2 35

关键词：血管紧张素原基因妊娠高血压综合征聚合酶链反应 M235T分子变异

Promising high-thermal-conductivity substrate material for high-power electronic device:silicon nitride ceramics

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Rare Metals 2020年第5期39卷 463-478页

作者： Feng Hu zhi-peng Xie Jian zhang Zun-Lan Hu Di An State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

High-thermal-conductivity silicon nitride ceramic substrates are indispensable components for nextgeneration high-power electronic devices because of their excellent mechanical properties and high thermal conductivities, which make them suitable for applications in complex and extreme environments. Here, we present an overview of the recent developments in the preparation of high-thermal-conductivity silicon nitride ceramics. First,the factors affecting the thermal conductivity of silicon nitride ceramics are described. These include lattice oxygen and grain boundary phases, as well the oxygen content of the crystal lattice, which is the main influencing ***, the methods to prepare high-thermal-conductivity silicon nitride ceramics are presented. Recent work on the preparation of high-thermal-conductivity silicon nitride is described in detail, including the raw materials used and the forming and sintering processes. Although great progress has been made, the development of a high-quality,low-cost fabrication process remains a challenge. Nevertheless, we believe that high-thermal-conductivity silicon nitride substrates are promising for massive practical applications in the next generation of high-power electronic devices.

关键词： Silicon nitride ceramics High thermal conductivity Preparation technique

Synergistically enhanced ORR and HER performance on Co-N-C coupled in-situ generated PtCo intermetallic

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Journal of Energy Chemistry 2025年第1期100卷 721-729页

作者： Guanyu Luo Min Song Lulu An Xiao Huang Qian zhang Chenhao zhang Tao Shen Shuang Wang Deli Wang Key Laboratory of Material Chemistry for Energy Conversion and Storage (Huazhong University of Science and Technology) Ministry of Education School of Chemistry and Chemical Engineering Huazhong University of Science and Technology

Integrating multi-scale sites in a composite catalyst is vital to realize efficient ***,a synergistic composite catalyst consisting of Co atomic sites and in-situ generated PtCo intermetallic compounds （IMCs）(o-PtCo@CoNC) is proposed through Co pre-anchoring and subsequent impregnation-reduction *** loading of Co atoms provides a chance for in-situ generating PtCo ordered intermetallic *** remaining Co single atoms and PtCo IMCs construct synergistic electrocatalytic *** from the ordered structure,synergistic effect of Pt Co IMCs and Co single atoms,o-PtCo@CoNC exhibits excellent electrocatalytic performance for oxygen reduction reaction （ORR） and hydrogen evolution reaction （HER） with mass activity of 1.21 A mgPt-1（at 0.9 V） and5.70 A mgPt-1（at an overpotential of 100 mV）,***,o-PtCo@CoNC delivers negligible loss of half-wave potential and overpotential during long-term stability test in acid solutions,with 13 mV decay after 50,000 potential cycles for ORR and a 2.7 mV decay after 20,000 potential cycles for *** integration strategy of single-atomic sites coupled IMCs paves the way for enhancing the activity and durability of Pt-based electrocatalysts.

关键词： Electrolytic reduction

Synthesis of polynorbornene with pendant moiety bearing azide and terminal alkyne groups

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Chinese Chemical Letters 2011年第7期22卷 785-788页

作者： Ze zhang zhi Wei peng Kun Zeng Fan School of Biochemical Engineering Anhui Polytechnic University Wuhu 241000 China Department of Chemistry University of Science and Technology of China Hefei 230026 China

A powerful approach to the synthesis of an unprecedented polynorbornene with pendant moiety bearing azide and terminal alkyne groups is developed. Two key intermediates, namely, 3-azido-5-（2-（trimethylsilyl）ethynyl） benzyl alcohol and 4-（4-azatricyclo [5.***.1.0^2.6]dec-8-en-4-yl） benzoic acid, were optimally synthesized for convergent synthesis of the corresponding monomer.

关键词： Polynorbomene Azide Alkyne Esterification Metathesis