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Blasting technologies of vibration damping in subway tunnel passing under upper buildings closely

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Engineering Sciences 2014年第6期12卷 63-70页

作者： fang junbo China Railway Tunnel Stock Co. Ltd. Luoyang Henan 471009 China

Reducing the blasting vibration is important for blasting excavation in subway tunnel *** the 3rd bid section of Line 3 of Qingdao subway project as an example,the distance between tunnel vault and ground is 5 ~ 8 *** order to insure the safety of the upper buildings,technologies of parallel cut with large diameter empty hole,one-time initiation and delay by parts,and multiple shallow holes were adopted in the *** results showed that the maximum value of vertical vibration was limited in the criterion allowance,and the upper buildings were not ***,problems were solved that the number of nonel detonator was difficult to meet the requirements of excavating a large cross-section tunnel by blasting,multiple cross-section could’t be initiated simultaneously,and construction efficiency was low,which ensure the construction safety and schedule.

关键词： blasting design parallel cut large diameter empty hole delay initiation shallow-hole blasting

地铁隧道爆破施工下穿地表建筑物的减振技术研究

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中国工程科学 2014年第11期16卷 58-64页

作者：方俊波中铁隧道集团有限公司河南洛阳471009

城市地铁区间隧道爆破施工中面临的一个重要问题就是降低爆破振动对临近地表建筑物的影响。青岛地铁一期工程03号线03标段下穿建筑物时，为了确保距隧道拱顶5～8m的地表建筑物安全，采用了大中空孔直眼掏槽技术、一次起爆分部延时爆破... 详细信息

城市地铁区间隧道爆破施工中面临的一个重要问题就是降低爆破振动对临近地表建筑物的影响。青岛地铁一期工程03号线03标段下穿建筑物时，为了确保距隧道拱顶5～8m的地表建筑物安全，采用了大中空孔直眼掏槽技术、一次起爆分部延时爆破、浅孔多眼等技术，将地表建筑物最大垂直振速控制在国标允许范围之内，隧道通过后地表建筑物完好无损。并在施工中解决了大断面隧道爆破施工导爆管雷管段数不能满足施工要求、分断面施工不能同时实施爆破作业，施工效率低下的问题，既保证了工程施工安全又满足了进度要求。

关键词：爆破设计直眼掏槽大直径中空孔分部延时起爆浅孔爆破

A methodology for laser tool setters calibration and its precise mathematical model

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Chinese Journal of Aeronautics 2024年第7期37卷 564-581页

作者： Tao fang Zixi fang Ze Zhong CHEN Zhiyong CHANG School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China Gina Cody School of Engineering and Computer Science Concordia UniversityMontrealQuebec H3G 1M8Canada Changsha Optimum CNC Corporation Changsha 410221China Institute for Aero-engine Smart Assembly of Shaanxi Province Xi’an 710072China

On-machine tool setting is a pivotal approach in achieving intelligent manufacturing,and laser tool setters have become a crucial component of smart machine *** tool setters play a crucial role in precisely measuring the dimensions of cutting tools during the part machining process,focusing on tool length and *** a measuring instrument,the positions of the laser axis of the laser tool setter need to be accurately calibrated before ***,in actual calibration scenarios,traditional calibration methods face challenges due to installation errors in the tool setter and geometric errors in the measuring *** address this issue,this study proposes a novel calibration ***,the calibration mechanism of the laser beam axis is *** on the accurate mathematical model of the laser beam and the measuring rod,and using the polygon clipping algorithm,the mathematical mechanism of the laser tool setter’s work is ***,a novel method is introduced to calculate the compensation distance between the laser beam reference point and the rod bottom center point at each moment during ***,by utilizing the kinematic chain of the tool setter calibration system,a new calibration method is developed to accurately calibrate the position of the laser beam axis in the machine tool coordinate ***,the accuracy of the calibration method is verified through simulation experiments and calibration *** method improves the calibration accuracy of the tool setter,and the mathematical model of the laser tool setter can be extended to the measurement of tools,thereby improving the precision of tool *** research significantly improves the efficient production performance of smart machine tools.

关键词： On-machine tool setting Smart machine tools Mathematical model Calibration method Laser tool sette

Triangle-free Graphs with Three Positive Eigenvalues

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Algebra Colloquium 2024年第3期31卷 525-540页

作者： fang Duan School of Mathematical Sciences Xinjiang Normal UniversityUrumqi 830017China

A graph G is called triangle-free if G does not contain any triangle as its induced *** G_(n)be the set of triangle-free graphs of order n each of which has three positive *** this paper,we find 20 specific graphs in G_(n),each of which has nullity no more than 2,and we show that in terms of three graph transformations all the other graphs of G_(n)can be constructed from these 20 specific ***,we completely characterize the triangle-free graphs with exactly three positive eigenvalues.

关键词： positive(negative)inertia index nullity triangle-free graph

Superior compound coatings prepared by low-temperature vanadium-nitrocarburizing duplex treatment

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Rare Metals 2024年第4期43卷 1828-1835页

作者： Gen Jin fang-fang Xu Xun-Xun Hu Yue Xu School of Chemistry Beihang UniversityBeijing100191China Guobiao(Beijing)Testing and Certification Co. LtdBeijing100088China School of Materials Science and Engineering Beihang UniversityBeijing100191China

Superior compound coatings were prepared on CK45 steel surface by vanadium-nitrocarburizing duplex treatment in low-temperature salt *** this study,the microhardness,the phase constitution and the compositional distribution in the coatings prepared under different conditions were systematically *** results indicated that the reactions among activated vanadium,carbon and nitrogen atoms occurred on the steel surface,leading to the formation of compound coatings composed of outermost and compound *** mechanism for the formation of compound layer as well as the growth kinetics of the layer was also *** the duplex treatment,the wear and corrosion resistances of steel surface were significantly *** was found that the growth kinetics of compound layer obeyed the parabolic law,with the activation energy of 122.82 kJ·moL^(-1).

关键词： Vanadium-nitrocarburizing duplex treatment Compound coatings Microstructure Formation mechanism Growth kinetics

Control of Virtual Synchronous Generator for Frequency Regulation Using a Coordinated Self-adaptive Method

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 175-184页

作者： Hongwei fang Zhiwei Yu School of Electrical and Information Engineering and Key Laboratory of Tianjin Electric Power System Simulation and Control Tianjin UniversityTianjin 300072China

Power inverter adopting virtual synchronous generator(VSG)control can provide inertia support for distributed generation ***,it cannot take into account the dynamic regulation characteristics of ***,when the system encounters a sudden change in load or disturbance,the dynamic process of frequency regulation will be greatly *** view of this issue,an improved VSG control strategy based on a coordinated self-adaptive(CSA)method is *** time domain analysis method is used to study the influences of virtual inertia and damping parameter perturbation on the system steady and dynamic ***,in order to make the control strategy suitable for large load changes and suppress frequency variations beyond the limit,the secondary frequency modulation is introduced into the control *** the coordinated adaptive control of virtual inertia,virtual damping and frequency modulation,the dynamic performance of vSG frequency regulation can be obviously *** and experiment results have verified the effectiveness of the proposed CSA control strategy.

关键词： Coordinated self-adaptive method frequency regulation time domain analysis virtual synchronous generator

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铁路隧道混凝土理论消耗量分析及计算

隧道建设（中英文） 2021年第5期41卷 721-728页

作者：方俊波罗斌智刘洪震中铁隧道局集团有限公司广东广州511400

混凝土超耗是隧道工程施工面临的难题,如何有效减小隧道混凝土超耗是项目成本管控的重点,也是难点。为有效降低施工成本,合理确定隧道混凝土消耗标准,做好施工管控,立足于隧道施工特点,从混凝土超耗原因、消耗组成、消耗量化分析及二次... 详细信息

混凝土超耗是隧道工程施工面临的难题,如何有效减小隧道混凝土超耗是项目成本管控的重点,也是难点。为有效降低施工成本,合理确定隧道混凝土消耗标准,做好施工管控,立足于隧道施工特点,从混凝土超耗原因、消耗组成、消耗量化分析及二次衬砌模板台车轮廓外放影响等方面,针对混凝土施工前后工序进行混凝土消耗量化计算及评估,得出:1)初期支护喷混凝土消耗量主要与设计量、回弹量及平均线性超挖量相关,喷混凝土理论消耗量是设计量的1.6~3.8倍;2)二次衬砌模筑混凝土消耗量主要与设计量及预留变形量相关,在实际预留变形量是设计预留量1/3的情况下,二次衬砌模筑混凝土理论消耗量是设计量的1.04~1.12倍;3)一般的二次衬砌模板台车结构强度及刚度较大,满足二次衬砌混凝土浇筑施工至初凝时的自重或冲击压力,定位时不需要将台车轮廓外放大,以防变形回落。

关键词：铁路隧道喷射混凝土模筑混凝土平均线性超挖回弹率预留变形量超耗率应耗量

Microbe-induced gene silencing explores interspecies RNAi and opens up possibilities of crop protection

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Science China(Life Sciences) 2024年第3期67卷 626-628页

作者： Rongxiang fang State Key Laboratory of Plant Genomics Institute of MicrobiologyChinese Academy of Sciencesand National Plant Gene Research CenterBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

In most eukaryotes, small RNA(sRNA)-mediated RNA silencing(or RNA interference, RNAi) is an evolutionarily conserved mechanism that regulates gene expression in a sequence-specific ***, s RNAs are produced by the RNase III enzymes Dicers and then incorporated into Argonaute(AGO) proteins to regulate gene expression by mRNA degradation.

关键词： protection conserved manner

A disk I/O optimized system for concurrent graph processing jobs

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Frontiers of Computer Science 2024年第3期18卷 13-29页

作者： Xianghao XU fang WANG Hong JIANG Yongli CHENG Dan FENG Peng fang School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China Department of Computer Science&Engineering University of Texas at ArlingtonArlingtonTX 76019USA College of Computer and Data Science Fuzhou UniversityFuzhou 350108China Zhejiang Lab Hangzhou 311121China

In order to analyze and process the large graphs with high cost efficiency,researchers have developed a number of out-of-core graph processing systems in recent years based on just one commodity *** the other hand,with the rapidly growing need of analyzing graphs in the real-world,graph processing systems have to efficiently handle massive concurrent graph processing(CGP)***,due to the inherent design for single graph processing job,existing out-of-core graph processing systems usually incur unnecessary data accesses and severe competition of I/O bandwidth when handling the CGP *** this paper,we propose GraphCP,a disk I/O optimized out-of-core graph processing system that efficiently supports the processing of CGP *** proposes a benefit-aware sharing execution model to share the I/O access and processing of graph data among the CGP jobs and adaptively schedule the graph data loading based on the states of vertices,which efficiently overcomes above challenges faced by existing out-of-core graph processing ***,GraphCP adopts a dependency-based future-vertex updating model so as to reduce disk I/Os in the future *** addition,GraphCP organizes the graph data with a Source-Sorted Sub-Block graph representation for better processing capacity and I/O access *** evaluation results show that GraphCP is 20.5×and 8.9×faster than two out-of-core graph processing systems GridGraph and GraphZ,and 3.5×and 1.7×faster than two state-of-art concurrent graph processing systems Seraph and GraphSO.

关键词： graph processing disk I/O concurrent jobs