检索结果-南通市图书馆

Heterovalent ion exclusion principle in atomically single site metal(hydr)oxide catalysts design

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science Bulletin 2024年第13期69卷 2009-2012页

作者： Daojin Zhou Fengmei Wang Yun Kuang xiaoming sun State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China Ocean Hydrogen Energy R&D Center Research Institute of Tsinghua University in ShenzhenShenzhen 518057China

Single-atom catalysts(SACs)are a series of catalysts in which all metal species are atomically dispersed on oxides,zeolites,sulfides,carbons,and so *** concept describing how atoms arrange with their nearest neighbors was proposed in 1969 by Van Hardeveld and co-workers[1],and researchers witness the growing popularity of SACs[2].However,the first long-standing issue in SACs is that the low concentration of active sites on the ***,weak chemical bonds between active sites with supports cannot sustain the functionalities of the SACs during long-term reactions,especially ones run at harsh conditions(high temperature or humidity,strong oxidative conditions).The loss or aggregation of active sites in SACs require substantial efforts to address the existing drawbacks in traditional SACs.

关键词： atomic bonds valent

Failure mechanism and safety control technology of a composite strata roadway in deep and soft rock masses:a case study

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第7期21卷 2427-2444页

作者： ZHAO Chengwei ZHOU Hui sun xiaoming ZHANG Yong MIAO Chengyu WANG Jian 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 State Key Laboratory for GeoMechanics and Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China

The construction of coal mines often encounters deep composite soft rock roadways,which is characterized by significant deformation and poor *** deeply study the failure mechanism and large deformation challenges of a composite strata roadway in deep and soft rock masses,a numerical model of 3DEC tetrahedral blocks was established based on the method of rock quality designation(RQD).The results showed that original support cannot prevent asymmetric failure and large deformation due to the adverse geological environment and unsuitable support *** to the failure characteristics,a coupling support of“NPR bolt/cable+mesh+shotcrete+steel pipe”was proposed to control the stability of the surrounding *** excellent mechanical properties of large deformation(approximately 400 mm)and high constant resistance force(bolt with 180 k N;cable with 350 k N)were evaluated by the tensile *** numerical results showed that the maximum deformation was minimized to 243 mm,and the bearing capacity of the surrounding rock of the roadway was *** field test results showed that the maximum deformation of the surrounding rock was 210 mm,and the forces of the NPR bolt and cable were stable at approximately 180 k N and 350 k N,*** demonstrated the effectiveness of the coupling support with the NPR bolt and cable,which could be a guiding significance for the safety control of large deformation and failure in deep composite soft rock roadways.

关键词： 3DEC Composite strata roadway Soft rock NPR bolt and cable Asymmetric large deformation

Sourcing the merits of 3D integrated air cathodes for highperformance Zn-air batteries by bubble pump consumption chronoamperometry

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第8期17卷 6951-6959页

作者： Mengxuan Li Linfeng Yu Hai Liu Chuanyi Zhang Jiazhan Li Liang Luo xiaoming sun State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China

Zn-air batteries(ZABs)as a potential energy conversion system suffer from low power density(typically≤200 mW·cm^(−2)).Recently,three-dimensional(3D)integrated air cathodes have demonstrated promising performance over traditional twodimensional(2D)plane ones,which is ascribed to enriched active sites and enhanced diffusion,but without experimental ***,we applied a bubble pump consumption chronoamperometry(BPCC)method to quantitatively identify the gas diffusion coefficient(D)and effective catalytic sites density(ρEC)of the integrated air cathodes for ***,the D andρEC values can instruct consequent optimization on the growth of Co embedded N-doped carbon nanotubes(CoNCNTs)on carbon fiber paper(CFP)and aerophilicity tuning,giving 4 times D and 1.3 timesρEC over the conventional 2D Pt/C-CFP *** a result,using the CoNCNTs with half-wave potential of merely 0.78 V ***(Pt/C:0.89 V ***),the superaerophilic CoNCNTs-CFP cathode-based ZABs exhibited a superior peak power density of 245 mW·cm^(−2) over traditional 2D Pt/C-CFP counterparts,breaking the threshold of 200 mW·cm^(−2).This work reveals the intrinsic feature of the 3D integrated air cathodes by yielding exact D andρEC values,and demonstrates the feasibility of BPCC method for the optimization of integrated electrodes,bypassing trial-and-error strategy.

关键词： Zn-air batteries three-dimensional(3D)integrated air cathodes superaerophilic gas diffusion coefficient effective catalytic sites density

Current Status and Perspectives of Dual-Atom Catalysts Towards Sustainable Energy Utilization

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第7期16卷 402-440页

作者： Yizhe Li Yajie Li Hao sun Liyao Gao Xiangrong Jin Yaping Li Zhi LV Lijun Xu Wen Liu xiaoming sun State Key Laboratory of Chemical Resource Engineering Beijing Advanced Innovation Center for Soft Matter Science EngineeringCollege of ChemistryBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China Xinjiang Coal Mine Mechanical and Electrical Engineering Technology Research Center Xinjiang Institute of EngineeringUrumqi 830023Xinjiang Uygur Autonomous RegionPeople’s Republic of China

The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-performance ***,heterogeneous atomically dispersed catalysts are considered as potential candidates for a wide range of *** to conventional cata-lysts,atomically dispersed metal atoms in carbon-based catalysts have more unsatu-rated coordination sites,quantum size effect,and strong metal-support interactions,resulting in exceptional catalytic *** these,dual-atomic catalysts(DACs)have attracted extensive attention due to the additional synergistic effect between two adja-cent metal *** have the advantages of full active site exposure,high selectiv-ity,theoretical 100%atom utilization,and the ability to break the scaling relationship of adsorption free energy on active *** this review,we summarize recent research advancement of DACs,which includes(1)the comprehensive understanding of the synergy between atomic pairs;(2)the synthesis of DACs;(3)characterization meth-ods,especially aberration-corrected scanning transmission electron microscopy and synchrotron spectroscopy;and(4)electrochemical energy-related *** last part focuses on great potential for the electrochemical catalysis of energy-related small molecules,such as oxygen reduction reaction,CO_(2) reduction reaction,hydrogen evolution reaction,and N_(2) reduction *** future research challenges and opportunities are also raised in prospective section.

关键词： Dual-atom catalysts Synergetic effect Electrocatalysis Oxygen reduction reaction CO_(2)reduction reaction Hydrogen evolution reaction N2 reduction reaction

Extraction and evolution of grader’s bionic morphological feature line using shape structure behavior function model

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2024年第2期17卷 74-84页

作者： Bin Qi Yubin Lan xiaoming sun He Zhu Yanhao Li Ke Lou College of Agricultural Engineering and Food Science Shandong University of TechnologyZibo 255049ShandongChina Shandong Provincial Engineering Technology Research Center for Agricultural Aviation Intelligent Equipment Zibo 255049China

To improve the innovation of agricultural machinery product styling,this paper proposes a shape structure behavior function(SSBF)model suitable for the industrial design *** feature line evolution method combining shape grammar and genetic algorithm was used for modelling the of the grader,which not only maintains the product style characteristics but also reflects the typical identification characteristics of the bionic prototype and produces a new product modelling *** conducting cognitive and recognition experiments on product styling features,the ranking of product styling features and the contribution of each component to product styling were *** method of combining shape grammar and quadratic Bézier curve was used to express and encode feature lines,and genetic algorithm was used to evolve biomimetic forms to form product feature lines with typical biological morphological features;The extracted form bionic elements were integrated into the grader modelling design,and the interaction evaluation was carried out through the genetic algorithm evolution *** basic form elements were extracted and analyzed,and the deduction rules were formulated and *** derived feature line geometric data considered the product’s image features and the bio-inspired prototype,which can be used for the follow-up guidance of industrial design schemes.

关键词： bionic design shape-structure-behavior-function SSBF biologically inspired design BID shape grammars Quadratic Bézier curves

Triaxial mechanical properties and precursors of instability damage in rocks with different laminar dip angles

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第2期21卷 648-661页

作者： sun xiaoming SHI Fukun DING Jiaxu TAO Zhigang HE Linsen YANG Liu ZHANG Yong MIAO Chengyu Inner Mongolia Research Institute China University of Mining and Technology(Beijing)Beijing 100083China State Key Laboratory for Tunnel Engineering China University of Mining and Technology(Beijing)Beijing 100083China

To investigate the mechanical failure characteristics of volcanic breccia with different bedding dip angles in deep layers,triaxial compression experiments were conducted on specimens taken from volcanic rock layers in the Junggar Basin,*** changing the confining pressure,we compared the mechanical properties,acoustic emission characteristics,and fractal features of the acoustic emission sequence for volcanic breccia with different bedding dip *** research results indicate that as the bedding dip angle increases,peak strength,internal friction angle,and cohesion exhibit a“U-shaped”variation *** correlation dimension of the acoustic emission amplitude was calculated using the G-P algorithm,revealing that volcanic breccia exhibits fractal ***,a positive correlation between the correlation dimension and the bedding dip angle was *** the stress of the test specimen reaches 0.8σ_(c),there is a significant decrease in the fractal dimension,serving as a criterion for predicting the failure of the *** analyzing the changes in fractal dimension at different stress levels,the slope of the fractal dimension△D<-0.5 can be used as a precursor to failure for test specimens with a bedding dip angle of 15°≤β≤45°.Similarly,when the bedding dip angle of the specimen is 0°≤β<15°or 45°<β≤90°,△D<0 can be considered as a precursor to specimen *** study provides theoretical references for understanding the failure patterns of volcanic rock.

关键词： Volcanic breccia Bedding dip Acoustic emission Fractal dimension Harbinger of destruction

Instability mechanism of mining roadway passing through fault at different angles in kilometre-deep mine and control measures of roof cutting and NPR cables

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第1期21卷 236-251页

作者： sun xiaoming WANG Jian ZHAO Wenchao MING Jiang ZHANG Yong LI Zhihu MIAO Chengyu GUO Zhibiao HE Manchao State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China

The angle α between the fault strike and the axial direction of the roadway produces different damage characteristics. In this paper, the research methodology includes theoretical analyses, numerical simulations and field experiments in the context of the Daqiang coal mine located in Shenyang, China. The stability control countermeasure of "pre-splitting cutting roof + NPR anchor cable"(PSCR-NPR) is simultaneously proposed. According to the different deformation characteristics of the roadway, the faults are innovatively classified into three types, with α of type I being 0°-30°, α of type II being 30°-60°, and α of type III being 60°-90°. The full-cycle stress evolution paths during mining roadway traverses across different types of faults are investigated by numerical simulation. Different pinch angles α lead to high stress concentration areas at different locations in the surrounding rock. The non-uniform stress field formed in the shallow surrounding rock is an important reason for the instability of the roadway. The pre-cracked cut top shifted the high stress region to the deep rock mass and formed a low stress region in the shallow rock mass. The high prestressing NPR anchor cable transforms the non-uniform stress field of the shallow surrounding rock into a uniform stress field. PSCR-NPR is applied in the fault-through roadway of Daqiang mine. The low stress area of the surrounding rock was enlarged by 3-7 times, and the cumulative convergence was reduced by 45%-50%. It provides a reference for the stability control of the deep fault-through mining roadway.

关键词： Kilometre-deep mine Fault Mining roadway Failure mechanism Pre-splitting cutting roof High pre-stress NPR anchor cable

Entropy consistency-based adaptive sampling method for determining the scale effect in the joint roughness coefficient

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2024年

作者： Jibo Qin Jun Ye xiaoming sun Shigui Du State Key Laboratory for Tunnel Engineering， China University of Mining and Technology-Beijing School of Mechanics and Civil Engineering， China University of Mining and Technology-Beijing Institute of Rock Mechanics， Ningbo University

The joint roughness coefficient （JRC） is one of the key parameters for evaluating the shear strength of rock joints. Because of the scale effect in the JRC， reliable JRC values are of great importance for most rock engineering projects. During the collection process of JRC samples， the redundancy or insufficiency of representative rock joint surface topography （RJST） information in serial length JRC samples is the essential reason that affects the reliability of the scale effect results. Therefore， this paper proposes an adaptive sampling method， in which we use the entropy consistency measure Q（a） to evaluate the consistency of the joint morphology information contained in adjacent JRC samples. Then the sampling interval is automatically adjusted according to the threshold Q(at) of the entropy consistency measure to ensure that the degree of change of RJST information between JRC samples is the same， and ultimately makes the representative RJST information in the collected JRC samples more balanced. The application results of actual cases show that the proposed method can obtain the scale effect in the JRC efficiently and reliably.

关键词：

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

不确定非线性系统的自适应滑模区域到达控制

北京航空航天大学学报 2024年第8期50卷 2482-2491页

作者：孙晓明马辛刘烨周悦邢博闻上海海洋大学工程学院上海深渊科学工程技术研究中心上海201306 复旦大学智能信息处理重点实验室上海200433 北京航空航天大学仪器科学与光电工程学院北京100191 上海工程技术大学电子电气工程学院上海201620

针对一类参数严格反馈型不确定非线性系统,考虑存在外界干扰的情况下,设计一种基于反推方法的自适应滑模区域到达控制器,提高系统对非匹配不确定性及未知干扰的鲁棒性。与传统的设定点控制或位置控制不同,区域到达算法的控制目标是一个... 详细信息

针对一类参数严格反馈型不确定非线性系统,考虑存在外界干扰的情况下,设计一种基于反推方法的自适应滑模区域到达控制器,提高系统对非匹配不确定性及未知干扰的鲁棒性。与传统的设定点控制或位置控制不同,区域到达算法的控制目标是一个以期望点为中心的目标区域。所设计控制器综合了人工势场法、自适应控制、反推技术、滑模控制和Lyapunov方法。利用人工势场法设计目标势能函数,将区域误差引入势能函数中,结合Lyapunov方法,可以实现对目标区域的到达跟踪控制。采用基于反推的区域控制思想,将高阶整体模型分解为低阶子系统,并分别设计相应的滑模面,同时在前n-1步中结合自适应律,能够在线估计非线性系统的不确定参数项,增加所设计控制器的适用性。基于Lyapunov理论证明闭环系统的全局渐近稳定性,仿真结果表明:所设计控制器有效。

关键词：严格反馈区域到达控制人工势场自适应控制滑模控制