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Numerical and theoretical study of large-scale failure of strata overlying sublevel caving mines with steeply dipping discontinuities

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1799-1815页

作者： Kaizong Xia Zhiwei Si Congxin Chen Xiaoshuang Li Junpeng Zou jiahao yuan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China School of Urban Construction Changzhou UniversityChangzhou 213164China Faculty of Engineering China University of Geosciences(Wuhan)Wuhan 430074China

The deformation and fracture evolution mechanisms of the strata overlying mines mined using sublevel caving were studied via numerical ***,an expression for the normal force acting on the side face of a steeply dipping superimposed cantilever beam in the surrounding rock was deduced based on limit equilibrium *** results show the following:(1)surface displacement above metal mines with steeply dipping discontinuities shows significant step characteristics,and(2)the behavior of the strata as they fail exhibits superimposition ***,failure first occurs in certain superimposed strata slightly far from the ***,with the constant downward excavation of the orebody,the superimposed strata become damaged both upwards away from and downwards toward the *** process continues until the deep part of the steeply dipping superimposed strata forms a large-scale deep fracture plane that connects with the *** deep fracture plane generally makes an angle of 12°-20°with the normal to the steeply dipping *** effect of the constant outward transfer of strata movement due to the constant outward failure of the superimposed strata in the metal mines with steeply dipping discontinuities causes the scope of the strata movement in these mines to be larger than *** strata in the metal mines with steeply dipping discontinuities mainly show flexural toppling ***,the steeply dipping structural strata near the goaf mainly exhibit shear slipping failure,in which case the mechanical model used to describe them can be simplified by treating them as steeply dipping superimposed cantilever *** taking the steeply dipping superimposed cantilever beam that first experiences failure as the key stratum,the failure scope of the strata(and criteria for the stability of metal mines with steeply dipping discontinuities mined using sublevel caving)can be obtained via iterative computations from the ke

关键词： sublevel caving mines universal distinct element code(UDEC)numerical approach large-scale ground movement steeply dipping superimposed cantilever beam toppling failure

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Estimating shear strength of high-level pillars supported with cemented backfilling using the HoekeBrown strength criterion

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 454-469页

作者： Kaizong Xia Congxin Chen Xiumin Liu Yue Wang Xuanting Liu jiahao yuan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China

Deep metal mines are often mined using the high-level pillars with subsequent cementation backfilling(HLSCB)mining *** the design stage,it is therefore important to have a reasonable method for determining the shear strength of the high-level pillars(*** and internal friction angle)when they are supported by cemented *** this study,a formula was derived for the upper limit of the confining pressure σ3max on a high-level pillar supported by cemented backfilling in a deep metal mine.A new method of estimating the shear strength of such pillars was then proposed based on the Hoek eBrown failure *** analysis indicates that the horizontal stress σhh acting on the cemented backfill pillar can be simplified by expressing it as a constant value.A reasonable and effective value for σ3max can then be *** value of s3max predicted using the proposed method is generally less than 3 *** this range,the shear strength of the high-level pillar is accurately calculated using the equivalent MohreCoulomb *** proposed method can effectively avoid the calculation of inaccurate shear strength values for the high-level pillars when the original HoekeBrown criterion is used in the presence of large confining pressures,*** situation in which the cohesion value is too large and the friction angle is too small can effectively be *** proposed method is applied to a deep metal mine in China that is being excavated using the HLSCB *** shear strength parameters of the high-level pillars obtained using the proposed method were input in the numerical *** numerical results show that the recommended level heights and sizes of the high-level pillars and rooms in the mine are rational.

关键词： Deep metal mines High-level pillars HoekeBrown strength criterion Cemented backfilling Confining pressure Shear strength

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含双软弱夹层岩质边坡稳定性上限解

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岩石力学与工程学报 2024年第2期43卷 412-423页

作者：袁家好鲁祖德陈从新孙朝燚范凯刘才华中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室湖北武汉430071 中国科学院大学北京100049

含软弱夹层岩质边坡稳定性由软弱夹层和岩体共同控制,多层软弱夹层边坡和单一夹层边坡在地质模型、破坏模式与稳定性分析方法方面存在明显的差异。结合传统塑性理论与广义塑性理论,将极限分析上限法应用于含一定厚度的双层软弱夹层岩质... 详细信息

含软弱夹层岩质边坡稳定性由软弱夹层和岩体共同控制,多层软弱夹层边坡和单一夹层边坡在地质模型、破坏模式与稳定性分析方法方面存在明显的差异。结合传统塑性理论与广义塑性理论,将极限分析上限法应用于含一定厚度的双层软弱夹层岩质边坡中,假设上夹层符合非关联流动法则,其余均符合关联流动法则,建立滑动破坏机构,提出含双夹层岩质边坡稳定系数的计算方法。结合算例,基于序列二次优化算法求解该边坡处于极限平衡状态下的稳定系数最小值并绘制对应的破坏机构,将计算结果与3DEC离散元数值分析结果进行对比分析。结果表明:软弱夹层倾角越大,滑动破坏面越靠近坡顶,边坡稳定性越差,理论计算结果与数值结果具有较好的一致性,验证了该方法的正确性。

关键词：边坡工程双层软弱夹层岩质边坡稳定性极限分析上限法广义塑性理论滑动破坏机构

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Metal-organic framework nanofilm enhances serum metabolic profiles for diagnosis and subtype of cardiovascular disease

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Chinese Chemical Letters 2023年第6期34卷 273-277页

作者： Dan Ouyang Zhihua Fu Guorong Li Chao Zhong jiahao yuan Huan Huang Juan Lin Gang Xu Zian Lin Ministry of Education Key Laboratory of Analytical Science for Food Safety and Biology Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food SafetyCollege of ChemistryFuzhou UniversityFuzhou 350108China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of Sciences(CAS)Fuzhou 350002China Department of Cardiology Fujian Provincial Governmental HospitalFuzhou 350003China

Cardiovascular disease(CVD)is a global health problem and is thought to be responsible for almost half of all deaths in the ***,currently available diagnostic methods for CVD are strongly depended on clinical observation and monitoring,which commonly result in false ***,an attractive strategy of a metal-organic framework(MOF)nanofilm-based laser desorption/ionization mass spectrometry(LDI-MS)was developed for enhancing serum metabolic profiling,which could provide precise diagnosis and molecular subtyping of *** porous MOF nanofilm fabricated on indium-tin oxide(ITO)glass possessed enhanced ionization efficiency and size-exclusion effect,which endowed it as substrate with high sensitivity and selectivity for serum ***,the MOF nanofilm with uniform surface and high orientation provided high-quality and high-reproducibility serum metabolic profiles(SMPs)without any tedious *** analysis of extracted serum metabolic fingerprints could successfully distinguish patients with CVD from healthy controls and also differentiate two major subtypes of *** work not only extends the application of MOF nanofilm as an attractive MS probe,but also provide an alternative way for precise diagnosis of CVD in molecular level.

关键词： Cardiovascular disease Mass spectrometry Metal-organic framework nanofilm Metabolites Precise diagnosis

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Precisely controlling the twist angle of epitaxial MoS_(2)/graphene heterostructure by AFM tip manipulation

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Chinese Physics B 2022年第8期31卷 173-177页

作者： jiahao yuan Mengzhou Liao Zhiheng Huang Jinpeng Tian Yanbang Chu Luojun Du Wei Yang Dongxia Shi Rong Yang Guangyu Zhang Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China College of Semiconductors(College of Integrated Circuits Hunan UniversityChangsha 410082China Songshan Lake Materials Laboratory Dongguan 523808China Department of Control Engineering Faculty of Electrical EngineeringCzech Technical University in PragueCzech Republic

Two-dimensional(2D)moirématerials have attracted a lot of attention and opened a new research frontier of twistronics due to their novel physical *** great progress has been achieved,the inability to precisely and reproducibly manipulate the twist angle hinders the further development of ***,we demonstrated an atomic force microscope(AFM)tip manipulation method to control the interlayer twist angle of epitaxial MoS_(2)/graphene heterostructure with an ultra-high accuracy better than 0.1°.Furthermore,conductive AFM and spectroscopic characterizations were conducted to show the effects of the twist angle on moirépattern wavelength,phonons and *** work provides a technique to precisely control the twist angle of 2D moirématerials,enabling the possibility to establish the phase diagrams of moiréphysics with twist angle.

关键词： AFM tip manipulation MoS_(2)/graphene heterostructure twist angle moirésuperlattice

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Gate-tunable large-scale flexible monolayer MoS_(2)devices for photodetectors and optoelectronic synapses

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Nano Research 2022年第6期15卷 5418-5424页

作者： Na Li Congli He Qinqin Wang Jianshi Tang Qingtian Zhang Cheng Shen Jian Tang Heyi Huang Shuopei Wang Jiawei Li Biying Huang Zheng Wei Yutuo Guo jiahao yuan Wei Yang Rong Yang Dongxia Shi Guangyu Zhang Songshan Lake Materials Laboratory Dongguan 523808China Beijing National Laboratory for Condensed Matter Physics Key Laboratory for Nanoscale Physics and DevicesInstitute of PhysicsChinese Academy of SciencesBeijing 100190China Institute of Advanced Materials Beijing Normal UniversityBeijing 100875China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China School of Integrated Circuits Beijing Innovation Center for Future Chips(ICFC)Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology(BNRist) Tsinghua UniversityBeijing 100084China Beijing Key Laboratory for Nanomaterials and Nanodevices Beijing 100190China

Photodetectors and optoelectronic synapses are vital for construction of artificial visual perception ***,the hardware implementations of optoelectronic-neuromorphic devices based on conventional architecture usually suffer from poor scalability,light response range,and limited ***,large-scale flexible monolayer MoS_(2)devices integrating photodetectors and optoelectronic synapses over the entire visible spectrum in one device have been realized,which can be used in photodetection,optical communication,artificial visual perception system,and optical artificial neural *** modulating gate voltages,we enable MoS_(2)-based devices to be photodetectors and also optoelectronic ***,the MoS_(2)-based optoelectronic synapses could implement many synaptic functions and neuromorphic characteristics,such as short-term memory(STM),long-term memory(LTM),paired-pulse facilitation(PPF),long-term potentiation(LTP)/long-term depression(LTD),and“learning-experience”***,an associative learning behavior(the classical conditioning Pavlov’s dog experiment)was emulated using paired stimulation of optical and voltage *** results facilitate the development of MoS_(2)-based multifunctional optoelectronic devices with a simple device structure,showing great potential for photodetection,optoelectronic neuromorphic computing,human visual systems mimicking,as well as wearable and implantable electronics.

关键词： MoS_(2) flexible devices gate-tunable photodetector optoelectronic synapse

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上市公司“答非所问”程度与审计费用--基于年报问询函与回函的综合研究

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审计研究 2023年第1期 99-111页

作者：郭照蕊袁嘉浩傅毅上海师范大学商学院 200234

年报问询函是证券交易所向年报披露存疑的上市公司发出的函件,有问有答才构成一次有效的问询回合,因此综合考察年报问询函和回函的经济后果更具意义。本文通过对2015-2020年间年报问询函及上市公司相应回函的文本分析构建了“答非所问... 详细信息

年报问询函是证券交易所向年报披露存疑的上市公司发出的函件,有问有答才构成一次有效的问询回合,因此综合考察年报问询函和回函的经济后果更具意义。本文通过对2015-2020年间年报问询函及上市公司相应回函的文本分析构建了“答非所问”程度指数并实证考察了其对审计费用的影响,结果发现,“答非所问”程度指数越高,上市公司支付的审计费用越高,进而表明,有针对性的释疑能够降低审计费用,回函质量的高低直接影响上市公司因问询函而支付的审计费用“溢价”。该现象受到一系列公司内外部特征的影响,相对于问询函回函长度越长、内部治理水平和外部制度环境越差,审计费用受“答非所问”程度影响而提升得越明显。本文从审计费用的视角证实了高质量的回函对上市公司发挥了积极作用。

关键词：年报问询函回函答非所问程度指数审计费用

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Germ cell-specific deletion of Pex3 reveals essential roles of PEX3-dependent peroxisomes in spermiogenesis

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The Journal of Biomedical Research 2024年第1期38卷 24-36页

作者： Yejin Yao Baolu Shi Xiangzheng Zhang Xin Wang Shuangyue Li Ying Yao Yueshuai Guo Dingdong Chen Bing Wang Yan yuan jiahao Sha Xuejiang Guo State Key Laboratory of Reproductive Medicine and Offspring Health Nanjing Medical UniversityNanjingJiangsu 211166China Reproductive and Genetic Branch the First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui 230001China State Key Laboratory of Reproductive Medicine and Offspring Health Women's Hospital of Nanjing Medical UniversityNanjing Maternity and Child Health Care HospitalNanjing Medical UniversityNanjingJiangsu 211166China.

Peroxisomes are organelles enclosed by a single membrane and are present in various *** abruption of peroxisomes is correlated with peroxisome biogenesis disorders and single peroxisomal enzyme deficiencies that induce diverse diseases in different ***,little is known about the protein compositions and corresponding roles of heterogeneous peroxisomes in various *** transcriptomic and proteomic analyses,we observed heterogenous peroxisomal components among different organs,as well as between testicular somatic cells and different developmental stages of germ *** Pex3 is expressed in both germ cells and Sertoli cells,we generated Pex3 germ cell-and Sertoli cell-specific knockout *** Pex3 deletion in Sertoli cells did not affect spermatogenesis,the deletion in germ cells resulted in male sterility,manifested as the destruction of intercellular bridges between spermatids and the formation of multinucleated giant *** analysis of the Pex3-deleted spermatids revealed defective expressions of peroxisomal proteins and spermiogenesis-related *** findings provide new insights that PEX3-dependent peroxisomes are essential for germ cells undergoing spermiogenesis,but not for Sertoli cells.

关键词： male infertility spermiogenesis peroxisome oxidative stress PEX3

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管理层“答非所问”、市场主体关注与股价同步性

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金融经济学研究 2022年第5期37卷 78-92页

作者：张震丁伟袁嘉浩傅毅上海师范大学商学院上海200234

业绩说明会制度是中国资本市场重要的信息传递渠道之一,但是在业绩说明会中存在不同程度的管理层“答非所问”现象,致使公司股价中私有信息或特质信息降低,股价的个体波动跟随系统性波动,提高了股价同步性。基于中国沪深两市上市公司201... 详细信息

业绩说明会制度是中国资本市场重要的信息传递渠道之一,但是在业绩说明会中存在不同程度的管理层“答非所问”现象,致使公司股价中私有信息或特质信息降低,股价的个体波动跟随系统性波动,提高了股价同步性。基于中国沪深两市上市公司2011—2020年度业绩说明会问答文本信息数据,研究管理层“答非所问”对股价同步性的作用机制,结果显示,在管理层“答非所问”时,分析师出于对自身专业认知水平的自信,会加大对相应公司的关注,但仍无法获取有增量价值的公司特质信息,反而增加股价中非公司特质的信息,导致股价同步性提高,即“力所不逮”效应;而投资者局限于自身专业认知水平,没有能力获取公司特质信息,因而更多采取观望态度,降低了换手率,提高了股价同步性,即“习得无助”效应。基于此,建议监管部门进一步规范业绩说明会的信息披露广度和深度,提升信息披露质量。

关键词：答非所问市场主体关注股价同步性力所不逮习得无助

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不同聘任方式中个人-组织匹配对科研人员离职影响的差异研究

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中国科技论坛 2023年第10期 119-129页

作者：刘霄袁家浩孙俊华南京大学教育研究院江苏南京210023 南京医科大学儿科学院江苏南京211166

如何通过组织支持满足科研人员的需求来提升其与组织的匹配度进而有效吸引和留住顶尖科研人才是科研管理的关键问题。利用全球16个国家的2418位全职科研人员的调查数据,结合个人需求和组织支持测度了科研人员与组织的匹配度,并构建结构... 详细信息

如何通过组织支持满足科研人员的需求来提升其与组织的匹配度进而有效吸引和留住顶尖科研人才是科研管理的关键问题。利用全球16个国家的2418位全职科研人员的调查数据,结合个人需求和组织支持测度了科研人员与组织的匹配度,并构建结构方程模型实证分析了个人-组织匹配对科研人员离职倾向的影响机制。研究发现,与全球平均水平相比,我国科研人员获得的组织支持更少,个人-组织匹配度略低,工作满意度更低,离职倾向更高;相较于终身制人员,我国合同制人员获得的组织支持更多,工作满意度略高,但个人-组织匹配度略低,离职倾向更高;组织支持和个人-组织匹配度都可以通过提升科研人员的工作满意度来降低其离职倾向,且个人-组织匹配的影响更大;相较于终身制人员,个人-组织匹配对降低合同制员工离职倾向的作用更大。因此,应在为科研人员提供组织支持的基础上,满足不同聘任方式科研人员的差异性需求,进而提升其与组织的匹配度,并重点关注那些需求高、支持少且对离职影响大的项目。

关键词：科研人员离职倾向个人-组织匹配聘任方式工作满意度

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