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A composite material model for investigation of micro-fracture mechanism of brittle rock subjected to uniaxial compression

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Journal of Central South University of Technology 2001年第4期8卷 258-262页

作者： CHEN Feng,SUN Zong qi,XU ji cheng,ZHANG jing yi (Key Laboratory of Nonferrous Metal Materials Science & Engineering, Central South University, Changsha 410083, China) Key Laboratory of Nonferrous Metal Materials Science & Engineering Central South University Changsha China

A two phase model of rock was proposed in order to investigate the mechanism of brittle fracture due to uniaxial compression, in which rock was considered to be a composite material consisting of hard grains and colloids. The stress state in colloid region near grains was calculated using Finite Element Method (FEM). The influence of the tensile stresses on the crack initiation and failure process of brittle rock subjected to uniaxial compression was investigated by numerical experiments. The FE results show that tensile stresses are induced easily in the neighboring area of hard grains with the maximum value near grain boundaries. The distribution of tensile stresses depends on the relative position of hard grains. The cracks initiated just near the boundary area of hard grains, which was governed by tensile stress. These results clearly reveal the micro fracture mechanism of brittle rock loaded by uniaxial compression. It can be concluded that the failure mode of brittle rock under uniaxial compression is still tensile fracture from the point view of microstructure. However, since the wide colloid region is still under compressive stress state, further propagation of boundary cracks through this region obviously needs more external load, thus causing the uniaxial compressive strength of rock much higher than its tensile strength obtained via Brazilian (splitting)

关键词： two-phase model micro-fracture rock uniaxial compression

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无形资产与企业市场价值动态研究

商业研究 2013年第9期 27-32页

作者：纪益成胡卓娟厦门大学经济学院福建厦门361005

本文使用2005-2007年中国制造业企业数据,采用静态结构模型检验无形资产和企业价值的相关关系,运用系统GMM估计分析创新投资和企业价值的动态效应,研究了以R&D投入、专利授权量和广告投入为代表的企业无形资产的市场价值。研究发现R&D... 详细信息

本文使用2005-2007年中国制造业企业数据,采用静态结构模型检验无形资产和企业价值的相关关系,运用系统GMM估计分析创新投资和企业价值的动态效应,研究了以R&D投入、专利授权量和广告投入为代表的企业无形资产的市场价值。研究发现R&D流量与企业价值无明显关系,R&D存量有着显著时滞性,并对企业价值产生积极影响,而且不同折旧率下R&D存量所代表的无形资产的相对影子价格不同;静态模型中专利没有市场溢价,而在动态模型中拥有大量专利的企业具有更高的企业价值,广告投入并没有产生正向价值,反而会拉低企业的当期利润。

关键词： R&D 无形资产市场价值

Identifying the dynamic behaviors in complete reconstruction of Co-based complex precatalysts during electrocatalytic oxygen evolution

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Journal of Energy Chemistry 2025年第1期100卷 226-233页

作者： jingfang Zhang Danyang Wu Linke Cai Youluan Lu Fanpeng cheng Lijuan Shi Qun yi Yao Liu yi Huang Key Laboratory of Green Chemical Engineering Process of Ministry of Education Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education Hubei Key Laboratory of Novel Reactor and Green Chemical Technology School of Chemical Engineering & Pharmacy Wuhan Institute of Technology Key Laboratory of Pesticide & Chemical Biology of Ministry of Education Engineering Research Center of Photoenergy Utilization for Pollution Control and Carbon Reduction of Ministry of Education College of Chemistry Central China Normal University College of Materials Science and Engineering Fuzhou University

Transition metal-based nanomaterials have emerged as promising electrocatalysts for oxygen evolution reaction（OER）. Considerable research efforts have shown that self-reconstruction occurs on these nanomaterials under operating conditions of OER process. However, most of them undergo incomplete reconstruction with limited thickness of reconstruction layer, leading to low component utilization and arduous exploration of real catalytic mechanism. Herein, we identify the dynamic behaviors in complete reconstruction of Co-based complexes during OER. The hollow phytic acid（PA） cross-linked CoFe-based complex nanoboxes with porous nanowalls are designed because of their good electrolyte penetration and mass transport ability, in favor of the fast and complete reconstruction. A series of experiment characterizations demonstrate that the reconstruction process includes the fast substitution of PA by OH-to form Co（Fe）(OH)xand subsequent potential-driven oxidation to Co（Fe）OOH. The obtained CoFeOOH delivers a low overpotential of 290 mV at a current density of 10 mA cm-2and a long-term *** experiment results together with theory calculations reveal that the Fe incorporation can result in the electron rearrangement of reconstructed CoFeOOH and optimization of their electronic structure,accounting for the enhanced OER activity. The work provides new insights into complete reconstruction of metal-based complexes during OER and offers guidelines for rational design of high-performance electrocatalysts.

关键词： Complete reconstruction Co-based complex Precatalysts Oxygen evolution reaction

Magneto‑Dielectric Synergy and Multiscale Hierarchical Structure Design Enable Flexible Multipurpose Microwave Absorption and Infrared Stealth Compatibility

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Nano-Micro Letters 2025年第2期17卷 401-416页

作者： Chen Li Leilei Liang Baoshan Zhang yi Yang Guangbin ji School of Electronic Science and Engineering Nanjing UniversityNanjing 210093People’s Republic of China College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016People’s Republic of China

Developing advanced stealth devices to cope with radar-infrared(IR)fusion detection and diverse application scenarios is increasingly demanded,which faces significant challenges due to conflicting microwave and IR cloaking mechanisms and functional integration ***,we propose a multiscale hierarchical structure design,integrating wrinkled MXene IR shielding layer and flexible Fe_(3)O_(4)@C/PDMS microwave absorption *** top wrinkled MXene layer induces the intensive diffuse reflection effect,shielding IR radiation signals while allowing microwave to pass ***,the permeable microwaves are assimilated into the bottom Fe_(3)O_(4)@C/PDMS layer via strong magneto-electric *** theoretical and experimental optimization,the assembled stealth devices realize a near-perfect stealth capability in both X-band(8–12 GHz)and long-wave infrared(8–14μm)wavelength ***,it delivers a radar cross-section reduction of−20 dB m^(2),a large apparent temperature modulation range(ΔT=70℃),and a low average IR emissivity of ***,the optimal device demonstrates exceptional curved surface conformability,self-cleaning capability(contact angle≈129°),and abrasion resistance(recovery time≈5 s).This design strategy promotes the development of multispectral stealth technology and reinforces its applicability and durability in complex and hostile environments.

关键词： Microwave absorption Radar-infrared compatible stealth Wrinkled MXene Magneto-dielectric synergy Multifunction

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纯电动车用锂离子电池发展现状与研究进展

工程科学学报 2019年第1期41卷 22-42页

作者：安富强赵洪量程志邱继一承周伟男李平北京科技大学新材料技术研究院北京100083 北京智行鸿远汽车有限公司北京102202

现阶段,锂离子电池已经成为电动汽车最重要的动力源,其发展经历了三代技术的发展(钴酸锂正极为第一代,锰酸锂和磷酸铁锂为第二代,三元技术为第三代).随着正负极材料向着更高克容量的方向发展和安全性技术的日渐成熟、完善,更高能量密度... 详细信息

现阶段,锂离子电池已经成为电动汽车最重要的动力源,其发展经历了三代技术的发展(钴酸锂正极为第一代,锰酸锂和磷酸铁锂为第二代,三元技术为第三代).随着正负极材料向着更高克容量的方向发展和安全性技术的日渐成熟、完善,更高能量密度的电芯技术正在从实验室走向产业化.本文从锂离子电池产学研结合的角度,从电池正负极材料,电池设计和生产工艺来分析动力电池行业最新动态和科学研究的前沿成果,并结合市场需求与政策导向来阐述动力电池的发展方向和技术路线的实现途径.

关键词：电动汽车锂离子电池三元材料硅基负极电池设计电池工艺

Decreased levels of phosphorylated synuclein in plasma are correlated with poststroke cognitive impairment

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Neural Regeneration Research 2025年第9期20卷 2598-2610页

作者： yi Wang Yuning Li Yakun Gu Wei Ma Yuying Guan Mengyuan Guo Qianqian Shao Xunming ji jia Liu Department of Clinical Laboratory Beijing Bo’ai HospitalChina Rehabilitation Research CenterCapital Medical UniversityBeijingChina Beijing Institute of Brain Disorders Laboratory of Brain DisordersMinistry of Science and TechnologyCollaborative Innovation Center for Brain DisordersBeijing Advanced Innovation Center for Big Data-based Precision MedicineCapital Medical UniversityBeijingChina Department of Neurosurgery Xuanwu HospitalCapital Medical UniversityBeijingChina

Poststro ke cognitive impairment is a major secondary effect of ischemic stroke in many patients;however,few options are available for the early diagnosis and treatment of this *** aims of this study were to(1)determine the specific relationship between hypoxic andα-synuclein during the occur of poststroke cognitive impairment and(2)assess whether the serum phosphorylatedα-synuclein level can be used as a biomarker for poststro ke cognitive *** found that the phosphorylatedα-synuclein level was significantly increased and showed pathological aggregation around the cerebral infa rct area in a mouse model of ischemic *** addition,neuronalα-synuclein phosphorylation and aggregation were observed in the brain tissue of mice subjected to chronic hypoxia,suggesting that hypoxia is the underlying cause ofα-synuclein-mediated pathology in the brains of mice with ischemic *** phosphorylatedα-synuclein levels in patients with ischemic stroke were significantly lower than those in healt hy subjects,and were positively correlated with cognition levels in patients with ischemic ***,a decrease in serum high-density lipoprotein levels in stroke patie nts was significantly correlated with a decrease in phosphorylatedα-synuclein *** ischemic stroke mice did not show significant cognitive impairment or disrupted lipid metabolism 14 days after injury,some of them exhibited decreased cognitive function and reduced phosphorylatedα-synuclein *** together,our results suggest that serum phosphorylatedα-synuclein is a potential biomarker for poststroke cognitive impairment.

关键词： biomarker high-density lipoprotein ischemic stroke phosphorylatedα-synuclein poststroke cognitive impairment

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中国盛夏褐飞虱北迁过程的动态数值模拟

昆虫学报 2000年第2期43卷 176-183页

作者：包云轩程极益程遐年储长树沈桐立南京农业大学南京210095 南京气象学院南京210044

以控制和影响褐飞虱Nilaparvatalugens(St l)迁飞过程的生理生态参数为依据 ,应用时空分辨率较高的中尺度数值预报模式—MM4和三维轨迹计算方法对我国盛夏褐飞虱的北迁过程进行了动态模拟。模拟结果及其与实测虫情资料的对比研究表明 :... 详细信息

以控制和影响褐飞虱Nilaparvatalugens(St l)迁飞过程的生理生态参数为依据 ,应用时空分辨率较高的中尺度数值预报模式—MM4和三维轨迹计算方法对我国盛夏褐飞虱的北迁过程进行了动态模拟。模拟结果及其与实测虫情资料的对比研究表明 :(1)我国盛夏褐飞虱北迁的虫源地主要在 2 2 5°N～ 2 7°N ,110°E～ 116°E之间。 (2 )空中迁飞路径有三条 :主径取 32°方位角 ,副径分别取 10°和 75°方位角。 (3)降落虫汇区有三个 :主降区为长江中下游稻区 ,副降区分别为鄂西北、川东北稻区和浙东南、闽北稻区。 (4)理论模拟与实际虫情普查分析比较吻合。

关键词：褐飞虱迁飞三维轨迹分析水稻害虫 MM4模式

Ni-MoS_2/γ-Al_2O_3催化剂的制备及其光催化性能研究

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人工晶体学报 2016年第1期45卷 211-216 223,223页

作者：单爽杨占旭高培玉贠丽敏邱继一承辽宁石油化工大学化学化工与环境学部抚顺113001

采用共沉淀结合水热合成方法,以γ-Al_2O_3为载体,制备出Ni-MoS_2/γ-Al_2O_3复合催化剂。采用X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)等方法对样品的结构与形貌进行表征。研究了MoS_2负载量、煅烧温度对NiMoS_2/γ-Al_2O_3复合催... 详细信息

采用共沉淀结合水热合成方法,以γ-Al_2O_3为载体,制备出Ni-MoS_2/γ-Al_2O_3复合催化剂。采用X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)等方法对样品的结构与形貌进行表征。研究了MoS_2负载量、煅烧温度对NiMoS_2/γ-Al_2O_3复合催化剂光催化降解罗丹明B性能的影响,并考察了催化剂的循环使用性能。结果表明:负载量为30wt%,煅烧温度为300℃的复合催化剂Ni-MoS_2/γ-Al_2O_3表面的MoS_2纳米片兼具有良好的结晶度和均匀分散性,其纳米片尺寸约为200 nm。可见光下,Ni-MoS_2/γ-Al_2O_3(MoS_2 30wt%/Ni 5wt%)复合催化剂对罗丹明B的降解效率能达到100%,且循环使用5次后,对罗丹明B的降解效率仍能够达到88.9%。

关键词： Ni-Mo S2/γ-Al2O3 罗丹明B 光催化共沉淀法水热法

Repetitive transcranial magnetic stimulation in Alzheimer’s disease:effects on neural and synaptic rehabilitation

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Neural Regeneration Research 2025年第2期20卷 326-342页

作者： yi ji Chaoyi Yang Xuerui Pang yibing Yan Yue Wu Zhi Geng Wenjie Hu Panpan Hu Xingqi Wu Kai Wang Department of Neurology The First Affiliated Hospital of Anhui Medical UniversityHefeiAnhui ProvinceChina Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders HefeiAnhui ProvinceChina Collaborative Innovation Center of Neuropsychiatric Disorders and Mental Health HefeiAnhui ProvinceChina Institute of Artificial Intelligence Hefei Comprehensive National Science CenterHefeiAnhui ProvinceChina Department of Psychology and Sleep Medicine The Second Affiliated Hospital of Anhui Medical UniversityHefeiAnhui ProvinceChina

Alzheimer’s disease is a neurodegenerative disease resulting from deficits in synaptic transmission and *** Alzheimer’s disease brain tends to be hyperexcitable and hypersynchronized,thereby causing neurodegeneration and ultimately disrupting the operational abilities in daily life,leaving patients *** transcranial magnetic stimulation is a cost-effective,neuro-modulatory technique used for multiple neurological *** the past two decades,it has been widely used to predict cognitive decline;identify pathophysiological markers;promote neuroplasticity;and assess brain excitability,plasticity,and *** has also been applied to patients with dementia,because it can yield facilitatory effects on cognition and promote brain recovery after a neurological ***,its therapeutic effectiveness at the molecular and synaptic levels has not been elucidated because of a limited number of *** study aimed to characterize the neurobiological changes following repetitive transcranial magnetic stimulation treatment,evaluate its effects on synaptic plasticity,and identify the associated *** review essentially focuses on changes in the pathology,amyloidogenesis,and clearance pathways,given that amyloid deposition is a major hypothesis in the pathogenesis of Alzheimer’s *** mechanisms associated with repetitive transcranial magnetic stimulation procedures and different pathways mediating gene transcription,which are closely related to the neural regeneration process,are also ***,we discuss the outcomes of animal studies in which neuroplasticity is modulated and assessed at the structural and functional levels by using repetitive transcranial magnetic stimulation,with the aim to highlight future directions for better clinical translations.

关键词： Alzheimer’s disease amyloid deposition apoptotic mechanisms biomarker neural regeneration neurodegeneration repetitive transcranial magnetic stimulation synaptic plasticity