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Numerical investigations of the failure mechanism evolution of rock-like disc specimens containing unfilled or filled flaws

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第1期24卷 64-79页

作者： Tian WANG Jian WANG sheng JIANG Jiahe zhang College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing 210098China School of Civil Engineering The University of SydneySydneyNSW 2006Australia

The mechanical responses and ultimate failure patterns of rocks are associated with the failure mechanism *** this study,smoothed particle hydrodynamics(SPH)method with the mixed-mode failure model is proposed to probe into failure mechanism evolutions for disc specimens upon *** tensile damage model and the Drucker-Prager model are used to calculate the tensile failure and shear failure of the material,*** is concluded that for flaw-unfilled disc specimens,the crack coalescence mechanism in the rock bridge area is affected by the flaw inclination angle and the material *** disc specimens with filled flaws,the incremental rate of tensile damage grows more rapidly when the disc and filling material have a closer ratio of tensile strength to cohesion,which makes the entire specimen response greater ***,with the increasing non-uniformity of filling distribution,the incremental rate of tensile-activated damage decreases and the disc specimen performs more ***,the influence of the fillings is greater when the flaw inclination angle is approaching 45°.It is proved that the proposed SPH method can be used to simulate the failure mechanism evolution of rocks,which lays a foundation for the study of more complex rock failure.

关键词： Smoothed particle hydrodynamics(SPH) Mixed-mode failure model Failure mechanism evolution Crack coalescence Filling distribution

氧化铈/镍-碳纳米管复合氧还原电催化剂的制备与性能研究

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安徽化工 2024年第1期50卷 98-101,107页

作者：王生洋张耀祖王欣茹周伟明孙驰张彩徐州工程学院江苏徐州221018

燃料电池阴极氧还原反应(ORR)的电子转移过程比较复杂,反应动力学缓滞,需要高效的电催化剂来加快反应速率。传统的贵金属铂基催化剂价格昂贵,因此亟需开发高性能、低成本的非贵金属催化剂作为替代材料。首先通过溶胶凝胶和热处理,得到... 详细信息

燃料电池阴极氧还原反应(ORR)的电子转移过程比较复杂,反应动力学缓滞,需要高效的电催化剂来加快反应速率。传统的贵金属铂基催化剂价格昂贵,因此亟需开发高性能、低成本的非贵金属催化剂作为替代材料。首先通过溶胶凝胶和热处理,得到了尺寸约为10 nm的氧化铈/镍复合纳米颗粒,然后通过催化甲烷热分解,得到了碳纳米管支撑的氧化铈/镍纳米材料。由于碳纳米管的形成,使催化剂与电解液的接触面积增加,并且改变了金属镍的电子结构,从而使其在碱性溶液中表现出较好的电催化氧还原活性,其循环伏安的氧还原峰电位约在-0.17 V和-0.51 V左右,氧还原极化曲线的开启电位约在-0.05 V vs. SCE。

关键词：电催化氧还原反应碳纳米管氧化铈/镍复合材料

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Interaction between encapsulated microbubbles:A finite element modelling study

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Chinese Physics B 2018年第8期27卷 315-323页

作者： Chen-Liang Cai Jie Yul Juan Tu Xia-sheng Guo Pin-Tong Huang Dong zhang Key Laboratory of Modem Acoustics（MOE） Department of PhysicsCollaborative Inovation Center of Advanced Microstructure Nanjing UniversityNanjing 210093China Department of Ultrasound the Second Affiliated Hospital of Zhejiang University School of MedicineHangzhou 310009China The State Key Laboratory of Acoustics Chinese Academy of SciencesBeijing 100190China

Theoretical studies on the multi-bubble interaction are crucial for the in-depth understanding of the mechanism behind the applications of ultrasound contrast agents （UCAs） in clinics. A two-dimensional （2D） axisymmetric finite element model （FEM） is developed here to investigate the bubble-bubble interactions for UCAs in a fluidic environment. The effect of the driving frequency and the bubble size on the bubble interaction tendency （viz., bubbles＇ attraction and repulsion）, as well as the influences of bubble shell mechanical parameters （viz., surface tension coefficient and viscosity coefficient） are discussed. Based on FEM simulations, the temporal evolution of the bubbles＇ radii, the bubble-bubble distance, and the distribution of the velocity field in the surrounding fluid are investigated in detail. The results suggest that for the interacting bubble-bubble couple, the overall translational tendency should be determined by the relationship between the driving frequency and their resonance frequencies. When the driving frequency falls between the resonance frequencies of two bubbles with different sizes, they will repel each other, otherwise they will attract each other. For constant acoustic driving parameters used in this paper, the changing rate of the bubble radius decreases as the viscosity coefficient increases, and increases first then decreases as the bubble shell surface tension coefficient increases, which means that the strength of bubble-bubble interaction could be adjusted by changing the bubble shell visco-elasticity coefficients. The current work should provide a powerful explanation for the accumulation observations in an experiment, and provide a fundamental theoretical support for the applications of UCAs in clinics.

关键词： ultrasound contrast agent microbubbles bubble-bubble interaction finite element model shellparameter

Ab initio investigation of excited state dual hydrogen bonding interactions and proton transfer mechanism for novel oxazoline compound

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Chinese Physics B 2019年第10期28卷 309-314页

作者： Yu-sheng Wang Min Jia Qiao-Li zhang Xiao-Yan Song Da-Peng Yang College of Physics and Electronics North China University of Water Resources and Electric PowerZhengzhou 450046China State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

Owing to the importance of excited state dynamical relaxation, the excited state intramolecular proton transfer(ESIPT) mechanism for a novel compound containing dual hydrogen bond(abbreviated as "1-enol") is studied in this *** density functional theory(DFT) and time-dependent density functional theory(TDDFT) method, the experimental electronic spectra can be reproduced for 1-enol compound. We first verify the formation of dual intramolecular hydrogen bonds, and then confirm that the dual hydrogen bond should be strengthened in the first excited state. The photo-excitation process is analyzed by using frontier molecular orbital(HOMO and LUMO) for 1-enol compound. The obvious intramolecular charge transfer(ICT) provides the driving force to effectively facilitate the ESIPT process in the S1 state. Exploration of the constructed S0-state and S1-state potential energy surface(PES) reveals that only the excited state intramolecular single proton transfer occurs for 1-enol system, which makes up for the deficiencies in previous experiment.

关键词： excited state intramolecular proton transfer potential energy surface intramolecular charge transfer infrared vibrational spectra

Distribution and conservation of near threatened plants in China

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Plant Diversity 2023年第3期45卷 272-283页

作者： Qin Liu Tian-Tian Xue Xiao-Xia zhang Xu-Dong Yang Fei Qin Wen-Di zhang Lei Wu Rainer W.Bussmann sheng-Xiang Yu State Key Laboratory of Systematic and Evolutionary Botany Institute of BotanyChinese Academy of SciencesBeijing 100093China College of Forestry Central South University of Forestry and TechnologyChangsha 410004China College of Life Sciences University of Chinese Academy of SciencesBeijing 100049China Institute of Botany and Bakuriani Alpine Botanical Garden Ilia State UniversityBotanical Str.1Tbilisi 0105Georgia Department of Botany State Museum for Natural History KarlsruheErbprinzenstraße 13Karlsruhe 76133Germany

Plants classified as Near Threatened(NT) are at high risk of becoming threatened because of anthropogenic interference and climate *** in conservation efforts,such species have however long been ***,we obtained 98,419 precise occurrence points for 2442 NT plants in China,and used species richness,species complementarity,and weighted endemism that consider all,endemic and narrow-ranged species in order to identify the diversity hotspots of NT *** we evaluated the conservation effectiveness of current nature reserves for *** results indicate that the diversity hotspots of NT plants were mainly confined to southwestern and southern China,and only 35.87% of hotspots and 71.5% of species were protected by nature *** hotspots in southwestern China(e.g.,Sichuan,Yunnan,Guangxi,and Hainan) were identified as conservation *** that NT plants include large proportions of endemic and narrow-ranged species,they represent an important value in conservation ***,more conservation efforts in the future should be tilted towards NT ***,when comparing with the recently updated NT list,there are already 87 species raised to threatened categories,while 328 species were lowered to least concern,56 species were now categorized as data deficient,and 119 species considered as uncertain due to changes of scientific *** is essential to carry out a continuous assessment of species’ threatened categories to realize targeting conservation.

关键词： Conservation Distribution patterns Diversity hotspots Nature reserves Red list Near threatened species

基于STC单片机的SF_(6)气体控制系统设计

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智能计算机与应用 2024年第9期14卷 187-191页

作者：张奕盛晓峰李咏臻李宪龙王伟张春元陈正龙上海理工大学健康科学与工程学院上海200093 上海健康医学院医疗器械学院上海201318 上海市医疗器械检验研究院上海201318

临床中常用肺功能残气量(Functional Residual Capacity,FRC)的测量结果来评估肺部疾病的严重程度,协助医生进行疾病的诊断和治疗。为了确保FRC值的准确性,通常需要基于示踪气体六氟化硫(SF_(6))的实时变化建立平衡方程来进行测量。由... 详细信息

临床中常用肺功能残气量(Functional Residual Capacity,FRC)的测量结果来评估肺部疾病的严重程度,协助医生进行疾病的诊断和治疗。为了确保FRC值的准确性,通常需要基于示踪气体六氟化硫(SF_(6))的实时变化建立平衡方程来进行测量。由于经过气体传感器转换后,SF_(6)气体信号的强度较弱,因此需要放大处理以获得更好的测量精度。本文设计了一种基于STC单片机的SF_(6)气体控制系统,通过模数转换(Analog to Digital Converter,ADC)计算SF_(6)浓度,再将浓度信号传送至显示屏,有助于控制SF_(6)气体的输出,降低惰性气体排放对受试人体的影响。该系统还具有直观的显示界面和报警功能,能够帮助医护人员更方便快捷地诊治肺部及呼吸道疾病,提高了医护人员的工作效率和安全性。

关键词：气体传感器 SF_(6) 控制系统设计 STC单片机

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基于BIM的大型交通枢纽工程机电安装技术应用

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建筑技术 2024年第6期55卷 760-763页

作者：马健刚张小龙刘占省武乐佳中铁建工集团第一建设有限公司北京100070 北京工业大学城市建设学部北京100124

大型交通枢纽工程机电安装体量广,专业管线交叉多,功能设备复杂,传统机电安装工作模式无法保障施工质量和效率。因此,本研究将BIM技术与新型施工技术相结合,用高效、绿色的智慧施工技术来实现正向BIM协同设计和工厂化预制。根据新建长... 详细信息

大型交通枢纽工程机电安装体量广,专业管线交叉多,功能设备复杂,传统机电安装工作模式无法保障施工质量和效率。因此,本研究将BIM技术与新型施工技术相结合,用高效、绿色的智慧施工技术来实现正向BIM协同设计和工厂化预制。根据新建长沙西站综合交通枢纽项目机电安装工程特点,系统阐述了BIM技术在管综深化、预制内保温风管、机电消声减振和工厂化支吊架等方面的应用,对今后类似项目的机电安装工程具有较高参考价值。

关键词： BIM 机电安装综合交通枢纽管线综合工厂化预制绿色施工

Occupational Mercury Exposure at a Thermometer Facility-Jiangsu Province, 2019

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China CDC weekly 2020年第42期2卷 827-831,I0001页

作者： Yanqiong Xu Xiaoling zhang Yiliang Xin Xiaowen Liu Xing sheng Enmin Ding Jingxin Xie Lei Han Hengdong zhang Xin Liu Department of Occupational Disease Prevention and Control Jiangsu Provincial Center for Disease Control and PreventionNanjingJiangsuChina Department of Technique Service Jiangsu Provincial Center for Disease Control and PreventionNanjingJiangsuChina

Summary What is already known about this topic?Mercury is still used in the manufacture of some thermometers in *** may pose health risks if exposure is not properly prevented and *** is added by this report?An onsite investigation of a workplace at a thermometer facility in Jiangsu Province in 2019 found heavily elevated airborne and urinary mercury levels among a massive number of workers exposed to mercury.

关键词： Mercury mercury properly

Mechanism of progressive failure of a slope with a steep joint under the action of freezing and thawing:model test

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Journal of Mountain Science 2022年第10期19卷 2999-3012页

作者： LI Cong zhang Rong-tang ZHU Jie-bing LU Bo SHEN Xiao-ke WANG Xiao-wei LIU Jie-sheng WU Liang-liang zhang Xin-zhou School of Civil Engineering and Architecture Wuhan Polytechnic UniversityWuhan 430023China Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources Changjiang River Scientific Research InstituteWuhan 430010China Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing 210098China

The stability of slope rock masses is influenced by freeze-thaw cycles in cold region,and the mechanism of stability deterioration is not *** order to understand the damage and progressive failure characteristics of rock masses under the action of freezing and thawing,a model test was conducted on slope with steep joint in this *** temperature,frost heaving pressure and deformation of slope rock mass were monitored in real-time during the test and the progressive failure mode was *** experimental results show that the temperature variations of cracking and the rock mass of a slope are *** are obvious latent heat stages in the temperature-change plot in the crack,but not in the slope rock *** frost heaving effect in the fracture is closely related to the constraint conditions,which change with the deformation of the *** frost heaving pressure fluctuates periodically during freezing and continues to decrease during *** surface deformation of the rock mass increases during freezing,and the deformation is restored when it ***-thaw cycling results in residual deformation of the rock mass which cannot be fully *** shows that the rock mass at the free side of the steep-dip joint rotates slightly under the frost heaving effect,causing fracture *** fracture propagation pattern is a circular arc at the beginning,then extends to the possible sliding direction of the rock *** heaving force and fracture water pressure are the key factors for the failure of the slope,which can cause the crack to penetrate the rock mass,and a landslide ensues when the overall anti-sliding resistance of the rock mass is overcome.

关键词： Rock slope Fractured rock mass Freeze-thaw cycle Model experiment Stability degradation mechanism Failure mode