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Multi-Criteria Wildfire Risk Hazard Assessment in GIS Environment: Projection for the Future and Impact on RES Projects Installation Planning
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作者 Aggelos Pallikarakis Flora Konstantopoulou 《Journal of Geoscience and Environment Protection》 2024年第5期242-265,共24页
It is alarming for the fact that Wildfires number, severity and consequently impact have significantly increased during the last years, an aftermath of the Climate Change. One of the most affected areas worldwide is M... It is alarming for the fact that Wildfires number, severity and consequently impact have significantly increased during the last years, an aftermath of the Climate Change. One of the most affected areas worldwide is Mediterranean, due to the unique combination of its type of vegetation and demanding climatic conditions. This research is focused on the Region of Epirus in Greece, an area with significant natural vegetation and a range of geomorphological aspects. In order to estimate the Wildfire Risk Hazard, several factors have been used: geomorphological (slope, aspect, elevation, TWI, Hydrographic network), social (Settlements and landfils, roads, overhead lines and substations), environmental (land cover) and climatic (Fire Weather Index). Through a multi-criteria decision analysis (MCDA) and an analytic hierarchy process (AHP) in a GIS environment, the Wildfire Risk Hazard has been estimated not only for current conditions but also for future projections for the near future (2031-2060) and the far future (2071-2100). The selected case study includes the potential impact of the Wildfires to the installed (or targeted to be installed) RES projects in the studied region. 展开更多
关键词 RES Projects Greece Epirus Analytic Hierarchy process multi-Criteria Decision Analysis
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MULTI-PERIODIC COLLISIONAL PROCESS BETWEEN INDIAN AND ASIAN CONTINENTS:A CASE OF EASTERN HIMALAYAN SYNTAXIS AND HENGDUAN MOUNTAINS 被引量:6
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作者 Zhong Dalai 1, Ding Lin 1, Zhang Jinjiang 1, Ji Jianqing 2(1 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 2 Department of Geology, Peking University, Beijing 100871, China) 《地学前缘》 EI CAS CSCD 2000年第S1期47-48,共2页
Our study area covered the Eastern Himalayan Syntaxis (EHS) and its southern extension (Hengduan Mountain or western Sichuan and Yunnan (WSY)) which is located at the orthogonal and oblique collisional front between I... Our study area covered the Eastern Himalayan Syntaxis (EHS) and its southern extension (Hengduan Mountain or western Sichuan and Yunnan (WSY)) which is located at the orthogonal and oblique collisional front between Indian and Asian continents during Cenozoic.Based on geometric and kinematic mapping of the major boundary or regional faults (Dongjug—Mainling(1), Anigiao(2) and Jali(3), Guyu(4) faults in EHS, Ailaoshan—Red River(5), Lancangjiang(6), Gaoligong(7), Binlangjiang(8) and Magok(9) faults in WSY) (see Fig.1), especially on abundant geochronological dating of the mylonitic rocks along these faults, and coupled with magmato\|metamorphic sequences of this region, we try to deal with the temporal and spatial relationships of collisional process to answer questions such as: (1) when did collision start ? (2) is thrusting as a initial and dominant deformation mode to absorb the crustal shortening after suturing, or earlier thrusting usually followed by large\|scale strike\|slip faults? (3) are the two structural patterns coeval at times, or do they occur alternatively during deformation history? (4) are the collisional and associate uplift processes a continuous one or periodic? Insight into such questions is crucial for better understanding of the continental deformation and testing the models available or constraining a new one. 展开更多
关键词 COLLISIONAL process multi\|period TECTONIC events Eastern HIMALAYA
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The multi-factor recombination and processes superimposition model for hydrocarbon accumulation:application to the Silurian in the Tarim Basin 被引量:9
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作者 Meng Qingyang Pang Xiongqi Gao Jianbo 《Petroleum Science》 SCIE CAS CSCD 2008年第1期13-19,共7页
The multi-factor recombination and processes superimposition model for hydrocarbon accumulation is put forward in view of the hydrocarbon geological characteristics of multiple episodes of structural evolution, multip... The multi-factor recombination and processes superimposition model for hydrocarbon accumulation is put forward in view of the hydrocarbon geological characteristics of multiple episodes of structural evolution, multiple sets of source-reservoir-seal assemblage, multiple cycles of hydrocarbon accumulation and multiple episodes of readjustment and reconstruction in the complex superimposed basins in China. It is a system including theories and methods that can help to predict favorable exploration regions. According to this model, the basic discipline for hydrocarbon generation, evolution and distribution in the superimposed basins can be summarized in multi-factor recombination, processes superimposition, multiple stages of oil filling and latest stage preservation. With the Silurian of the Tarim basin as an example, based on the reconstruction of the evolution history of the four factors (paleo-anticline, source rock, regional cap rock and kinematic equilibrium belt) controlling hydrocarbon accumulation, this model was adopted to predict favorable hydrocarbon accumulation areas and favorable exploration regions following structural destruction in three stages of oil filling, to provide guidance for further exploration ofoil and gas in the Silurian of the Tarim basin. 展开更多
关键词 multi-factor recombination processes superimposition Tarim Basin SILURIAN favorable exploration region prediction
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FE simulation and process analysis on forming of aluminum alloy multi-layer cylinder parts with flow control forming 被引量:5
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作者 王新云 吴有生 +1 位作者 夏巨谌 胡国安 《中国有色金属学会会刊:英文版》 CSCD 2005年第2期452-456,共5页
The aluminum alloy parts used in airbag of car were studied with flow control forming(FCF) method, which was a good way to low forming force and better mechanical properties. The key technology of FCF was the design o... The aluminum alloy parts used in airbag of car were studied with flow control forming(FCF) method, which was a good way to low forming force and better mechanical properties. The key technology of FCF was the design of control chamber to divide metal flow. So, the design method of FCF was analyzed and two type of control chamber were put forward. According to divisional principle, calculation model of forming force and approximate formula were given. Then forming process of aluminum alloy multi-layer cylinder parts was simulated. The effect of friction factor, die radius and punch velocity on metal flow and forming force was obtained. Finally, the experiment was preformed under the direction of theory and finite element(FE) simulation results. And the qualified parts were manufactured. The simulation data and experimental results show that the forming sequence of inner wall and outer wall, and then the force step, can be controlled by adjusting the process parameters. And the FCF technology proposed has very important application value in precision forging. 展开更多
关键词 流动控制成型 多层圆筒 力学计算 铝合金 有限元
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Multi-objective optimization of process parametersduring low-pressure die casting of AZ91Dmagnesium alloy wheel castings 被引量:10
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作者 Chen Zhang Yu Fu +1 位作者 Han Wang Hai Hao 《China Foundry》 SCIE 2018年第5期327-332,共6页
Multi-objective optimization has been increasingly applied in engineering where optimal decisions need to be made in the presence of trade-offs between two or more objectives. Minimizing the volume of shrinkage porosi... Multi-objective optimization has been increasingly applied in engineering where optimal decisions need to be made in the presence of trade-offs between two or more objectives. Minimizing the volume of shrinkage porosity, while reducing the secondary dendritic arm spacing of a wheel casting during low-pressure die casting(LPDC) process, was taken as an example of such problem. A commercial simulation software Pro CASTTM was applied to simulate the filling and solidification processes. Additionally, a program for integrating the optimization algorithm with numerical simulation was developed based on SiPESC. By setting pouring temperature and filling pressure as design variables, shrinkage porosity and secondary dendritic arm spacing as objective variables, the multi-objective optimization of minimum volume of shrinkage porosity and secondary dendritic arm spacing was achieved. The optimal combination of AZ91 D wheel casting was: pouring temperature 689 °C and filling pressure 6.5 kPa. The predicted values decreased from 4.1% to 2.1% for shrinkage porosity, and 88.5 μm to 81.2 μm for the secondary dendritic arm spacing. The optimal results proved the feasibility of the developed program in multi-objective optimization. 展开更多
关键词 magnesium alloy multi-objective optimization process parameters shrinkage porosity secondary DENDRITIC arm SPACING
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Parallelizing AT with open multi-processing and MPI
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作者 罗承明 田顺强 +3 位作者 王坤 张满洲 张庆磊 姜伯承 《Nuclear Science and Techniques》 SCIE CAS CSCD 2015年第3期17-20,共4页
Simulating charged particle motion through the elements is necessary to understand modern particle accelerators. The particle numbers and the circling turns in a synchrotron are huge, and a simulation can be timeconsu... Simulating charged particle motion through the elements is necessary to understand modern particle accelerators. The particle numbers and the circling turns in a synchrotron are huge, and a simulation can be timeconsuming. Open multi-processing(Open MP) is a convenient method to speed up the computing of multi-cores for computers based on share memory model. Using message passing interface(MPI) which is based on nonuniform memory access architecture, a coarse grain parallel algorithm is set up for the Accelerator Toolbox(AT)for dynamic tracking processes. The computing speedup of the tracking process is 3.77 times with a quad-core CPU computer and the speed almost grows linearly with the number of CPU. 展开更多
关键词 多处理技术 并行算法 MPI 开放式 粒子加速器 带电粒子运动 消息传递接口 动态跟踪
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Analysis of the Multi-Pivot Quicksort Process 被引量:1
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作者 Mahmoud Ragab Beih El-Sayed El-Desouky Nora Nader 《Open Journal of Modelling and Simulation》 2017年第1期47-58,共12页
In this paper, we study a new version from Dual-pivot Quicksort algorithm when we have some other number of pivots. Hence, we discuss the idea of picking pivots ?by random way and splitting the list simultaneously acc... In this paper, we study a new version from Dual-pivot Quicksort algorithm when we have some other number of pivots. Hence, we discuss the idea of picking pivots ?by random way and splitting the list simultaneously according to these. The modified version generalizes these results for multi process. We show that the average number of swaps done by Multi-pivot Quicksort process and we present a special case. Moreover, we obtain a relationship between the average number of swaps of Multi-pivot Quicksort and Stirling numbers of the first kind. 展开更多
关键词 QUICKSORT Convergence multi-Pivot QUICKSORT process STIRLING Number of the First KIND
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MULTI-AGENT BASED DISTRIBUTED PROCESS PLANNING MANAGEMENT
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作者 赵世光 严隽琪 马登哲 《Journal of Shanghai Jiaotong university(Science)》 EI 1999年第2期91-96,共6页
A distributed process planning system based on autonomous multi agent system to solve a distributed process plan task in a manufacturing environment was presented. A distributed agent based process plan structure was ... A distributed process planning system based on autonomous multi agent system to solve a distributed process plan task in a manufacturing environment was presented. A distributed agent based process plan structure was shown to be a viable alternative to hierarchical systems providing real time response to shop floor condition. An outline was done to show how to structure a distributed process plan and how its management may be achieved among manufacturers of parts that form a product. Communication between the agents involved in a distributed process planning was also shown to be important, with the controlling agent having an overall supervision of the plans. Based on the reference model a software tool was developed to realize it. 展开更多
关键词 multi AGENT process PLAN COMMUNICATION COOPERATION
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Modelling and Multi-Objective Optimal Control of Batch Processes Using Recurrent Neuro-fuzzy Networks 被引量:2
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作者 Jie Zhang 《International Journal of Automation and computing》 EI 2006年第1期1-7,共7页
In this paper, the modelling and multi-objective optimal control of batch processes, using a recurrent neuro-fuzzy network, are presented. The recurrent neuro-fuzzy network, forms a "global" nonlinear long-range pre... In this paper, the modelling and multi-objective optimal control of batch processes, using a recurrent neuro-fuzzy network, are presented. The recurrent neuro-fuzzy network, forms a "global" nonlinear long-range prediction model through the fuzzy conjunction of a number of "local" linear dynamic models. Network output is fed back to network input through one or more time delay units, which ensure that predictions from the recurrent neuro-fuzzy network are long-range. In building a recurrent neural network model, process knowledge is used initially to partition the processes non-linear characteristics into several local operating regions, and to aid in the initialisation of corresponding network weights. Process operational data is then used to train the network. Membership functions of the local regimes are identified, and local models are discovered via network training. Based on a recurrent neuro-fuzzy network model, a multi-objective optimal control policy can be obtained. The proposed technique is applied to a fed-batch reactor. 展开更多
关键词 Optimal control batch processes neural networks multi-objective optimisation.
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Existence and joint continuity of local time of multi-parameter fractional Lévy processes
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作者 林正炎 程宗毛 Xing-ming GUO 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2009年第3期381-390,共10页
In this paper, we introduce the definition of a multi-parameter fractional Lévy process and its local time, and show its decomposition. Using the decomposition, we prove existence and joint continuity of its loca... In this paper, we introduce the definition of a multi-parameter fractional Lévy process and its local time, and show its decomposition. Using the decomposition, we prove existence and joint continuity of its local time. 展开更多
关键词 multi-parameter fractional Lévy process fractional Brownian sheet local time Gaussian random field multi-parameter Poisson process multi-parameter Brownian motion
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Microstructure and mechanical properties of Al-Si-Ni coating on Cu-Cr substrate prepared by multi-permeation and friction stir processing 被引量:2
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作者 Yin Wang Ruidi Li Tiechui Yuan 《Nano Materials Science》 CAS 2019年第3期224-228,共5页
The surface of copper-chromium alloy was processed by Al-Si-Ni multi-permeation and friction stir processing,and the microstructure and mechanical properties of the surface layer were tested by scanning electron micro... The surface of copper-chromium alloy was processed by Al-Si-Ni multi-permeation and friction stir processing,and the microstructure and mechanical properties of the surface layer were tested by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),microhardness tester and friction testing machine.The results show that Al,Si and Ni elements are fully permeated into the surface of copper-chromium alloy after multielement co-infiltration and friction stir processing.In the observation of the microstructures,we found that the reticular structure is fragmented and distributed in the stir zone region.Microstructure becomes finer and grains refinement.The micro hardness of the copper-chromium alloy increased to 129 HV,44.9%higher than that of the original matrix.The main reasons of microhardness enhancement are solid solution strengthening,fine grains strengthening and dispersion strengthening.The friction test results show that the friction coefficient is basically stable at 0.69 and the wear mass is only 0.0017 g after 10 min of friction test.The improvement of wear resistance was attributed to the increase of microhardness of the alloy surface. 展开更多
关键词 Copper-chromium alloy Al-Si-Ni multi-permeation Friction STIR processing Microstructure Mechanical properties
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Influence of core property on multi-electron process in slow collisions of isocharged sequence ions with neon
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作者 卢荣春 于得洋 +2 位作者 邵曹杰 阮芳芳 蔡晓红 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第11期475-488,共14页
Influence of core property on multi-electron process in the collisions of q = 6-9 and 11 isocharged sequence ions with Ne is investigated in the keV/u region. The cross-section ratios of double-, triple-, quadruple- a... Influence of core property on multi-electron process in the collisions of q = 6-9 and 11 isocharged sequence ions with Ne is investigated in the keV/u region. The cross-section ratios of double-, triple-, quadruple- and total multielectron processes to the single electron capture process as well as the partial ratios of different reaction channels to the relevant multi-electron process are measured by using position-sensitive and time-of-flight techniques. The experimental data are compared with the theoretical predictions including the extended classical over-barrier model, the molecular Columbic barrier model and the semi-empirical scaling law. Results show a core effect on multi-electron process of isocharge ions colliding with Neon, which is consistent with the results of Helium we obtained previously. 展开更多
关键词 isocharged sequence ions multi-electron process classical over-barrier model
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A Multi-Scale Study on Silicon-Oxide Etching Processes in C_4F_8/Ar Plasmas 被引量:2
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作者 眭佳星 张赛谦 +2 位作者 刘增 阎军 戴忠玲 《Plasma Science and Technology》 SCIE EI CAS CSCD 2016年第6期666-673,共8页
A multi-scale numerical method coupled with the reactor,sheath and trench model is constructed to simulate dry etching of SiO_2 in inductively coupled C_4F_8 plasmas.Firstly,ion and neutral particle densities in the r... A multi-scale numerical method coupled with the reactor,sheath and trench model is constructed to simulate dry etching of SiO_2 in inductively coupled C_4F_8 plasmas.Firstly,ion and neutral particle densities in the reactor are decided using the CFD-ACE+ commercial software.Then,the ion energy and angular distributions(IEDs and IADs) are obtained in the sheath model with the sheath boundary conditions provided with CFD-ACE+.Finally,the trench profile evolution is simulated in the trench model.What we principally focus on is the effects of the discharge parameters on the etching results.It is found that the discharge parameters,including discharge pressure,radio-frequency(rf) power,gas mixture ratios,bias voltage and frequency,have synergistic effects on IEDs and IADs on the etched material surface,thus further affecting the trench profiles evolution. 展开更多
关键词 plasma etching multi-scale model trench profile surface process
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Multi-subpulse process of large time-bandwidth product chirp signal
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作者 张洪纲 范花玉 +1 位作者 何少华 刘泉华 《Journal of Beijing Institute of Technology》 EI CAS 2015年第4期501-507,共7页
To prevent the long-time coherent integration and limited range window stumbling blocks of stretch processing and reduce computational complexity, a novel method called multi-subpulse process of large time-bandwidth p... To prevent the long-time coherent integration and limited range window stumbling blocks of stretch processing and reduce computational complexity, a novel method called multi-subpulse process of large time-bandwidth product linear frequency modulating ( LFM ) signal ( i. e. chirp ) is proposed in this paper. The wideband chirp signal is split up into several compressed subpulses. Then the fast Fourier transform (FFT) is used to reconstruct the high resolution range profile ( HR- RP) in a relative short computation time. For multi-frame, pulse Doppler (PD) process is performed to obtain the two-dimension range-Doppler (R-D) high resolution profile. Simulations and field ex- perimental results show that the proposed method can provide high-quality target profile over a large range window in a short computation time and has the promising potential for long-time coherent in- tegration. 展开更多
关键词 multi-subpulse process large time-bandwidth product chirp signal COMPUTATIONALCOMPLEXITY coherent integration
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Study on Multi-enterprise Collaborative Resource Planning Based Process-oriented Decision Model
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作者 SHI Jinhua~1 HE Yingying~2 LIU Jianmin~3 1.School of Management,Harbin Institute of Technology,Harbin 150001,China 2.Weihai Nongyou Software Company,Weihai 264209,China 3.Weihai High-tech Pioneering Service Center,Weihai 264209,China 《武汉理工大学学报》 CAS CSCD 北大核心 2006年第S2期600-606,共7页
Aiming to share the information,knowledge and optimizing resource via collaborating with multiple external partners across their supply chains,the concept model and system framework of multi-enterprises collaborative ... Aiming to share the information,knowledge and optimizing resource via collaborating with multiple external partners across their supply chains,the concept model and system framework of multi-enterprises collaborative resource planning (MECORP) are put forward.While there is Considerable pressure to improve the operation of MECORP system,their inherent complexity can make modelling a MECORP system a difficult task.Yet there could be considerable benefits in designing MECORP taking into account the operation of the system.In order to address the central research issue of developing of a methodology that can assist a manager in making decisions by modelling the operation of MECORP system.The methodology called process-oriented deci- sion model (PODM) is presented in the paper.This uses an abstracted network to model MECORP system.The MECORP system supported by PODM,can effective optimize the manifold resource,coordinate the relationship of multiple partners and assist deci- sion.Finally,an industry excample of MECORP system is described to illustrate the application of PODM. 展开更多
关键词 COLLABORATION DECISION multi-enterprises operation process RESOURCE planning
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MULTI-SCALES RELAXATION PROCESSES OF SHORT FIBER OF NEMATIC LIQUID CRYSTALLINE COPOLYMER IN POLYCARBONATE MATRIX
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作者 Yu, Ruo-bing Yu, Wei Zhou, Chi-xing 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2008年第1期99-104,共6页
Multi-scales relaxation processes of short fiber of a nematic liquid crystalline copolymer(LCP)in polycarbonate matrix were investigated.First,the structure relaxation of LCP was studied by rheology.The relaxation spe... Multi-scales relaxation processes of short fiber of a nematic liquid crystalline copolymer(LCP)in polycarbonate matrix were investigated.First,the structure relaxation of LCP was studied by rheology.The relaxation spectrum of the nematic liquid crystalline copolymer at 295℃was calculated from the combined dynamic modulus.There are three kinds of relaxation mechanisms for nematic liquid crystalline copotymer:the relaxation of chain orientation,the relaxation of deformed polydomains and the coalescence of pol... 展开更多
关键词 Liquid crystalline copolymer multi-scales Relaxation processes
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煤矿智能快速掘进关键技术研究现状及展望 被引量:4
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作者 毛君 杨润坤 +4 位作者 谢苗 卢进南 王贺 刘治翔 王帅 《煤炭学报》 EI CAS CSCD 北大核心 2024年第2期1214-1229,共16页
针对煤矿巷道掘进智能化建设情况,探讨了现阶段分别以连采机、掘锚一体机、全断面掘进系统、掘锚机为核心的四大类智能快速掘进成套装备发展现状,分析了四大类智能快掘装备与地质条件适用性,提出了实现煤矿智能化掘进需要解决的关键技... 针对煤矿巷道掘进智能化建设情况,探讨了现阶段分别以连采机、掘锚一体机、全断面掘进系统、掘锚机为核心的四大类智能快速掘进成套装备发展现状,分析了四大类智能快掘装备与地质条件适用性,提出了实现煤矿智能化掘进需要解决的关键技术的问题,探讨了以信息传输与智能分析技术、智能感知技术、精确定位导航技术,自主定型定向截割技术、掘进机远程自主截割控制技术以及多级多工序智能协同控制技术为基础的智能化掘进实现途径;基于复杂地质条件下煤矿巷道掘进亟待解决的关键问题,提出了以掘进作业功能需求、掘进工艺要求为依据的系统化分析、模块化设计、功能优化组合的设计方法;研究了以虚控实、虚实结合的多级数字孪生构架,基于掘进巷道设备、环境、地质构造多维信息再现实现掘进机远程控制;提出了单机智能化、系统协同化、井下智控与地面远程监控相协同的控制方法。开发了新型的无重复碾压柔性超前支护技术、截割部多级伸缩截割技术、智能锚固机组多钻机并行作业等技术,研制了具有掘、支、锚、运、探多工序并行作业的新型快速掘进作业联合机组,提出了掘进机器人、超前支护机器人、锚固机器人、辅助运输机器人组柔性并行作业技术;提出了基于数据驱动的多机多工序协同控制行为规划决策方法。提出构建完整的煤矿井下跨系统全时空信息数字感知体系,构建集井下现场生产状态、掘进巷道空间信息、掘进装备状态、风险信息等多参量、多尺度、全时空特性的数据感知智能化监控平台,实现虚拟系统与实际掘进系统实时通信,通过数据驱动规划分析实现智能化、少人化掘进。 展开更多
关键词 智能掘进 自主定性定向截割 柔性并行作业 多级多工序协同控制 数字孪生
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Evaporation of multi-components in Ti-25Al-25Nb melt during induction skull melting process
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作者 郭景杰 刘贵仲 +3 位作者 苏彦庆 丁宏升 贾均 傅恒志 《中国有色金属学会会刊:英文版》 EI CSCD 2002年第4期587-591,共5页
Based on activity calculation model, the activity coefficients of Ti, Al and Nb components of Ti 25Al 25Nb (mole fraction, %) melt, the vapor pressures of corresponding components and the evaporation loss rates were c... Based on activity calculation model, the activity coefficients of Ti, Al and Nb components of Ti 25Al 25Nb (mole fraction, %) melt, the vapor pressures of corresponding components and the evaporation loss rates were calculated. Utilizing these activity coefficients and the vapor pressures, the relative evaporation coefficient is used to judge the evaporation tendency of these components. The evaporation tendency among the three components were compared and the result shows that the evaporation tendency is that: AlTi>Nb. Evaporation loss rate increases with the increase of melting temperature and decreases with the increase of chamber pressure. There exists an impeding pressure p impe of Al element evaporation during induction skull melting process of Ti 25Al 25Nb alloy. The impeding pressure can be written as p impe =8.1 p e, where p e represents the equilibrium partial pressure. The calculation of evaporation loss of Al element also showed that when chamber pressure exceeds p impe , the Al volatilization losses could be ignored. In order to prevent the evaporation loss of components, the pressure in the vacuum chamber should not below p impe . 展开更多
关键词 TiAlNb合金 感应熔炼 铸造 多组分蒸发
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Reconfigurable Multi-Butterfly Parallel Radix-r FFT Processor
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作者 Jiyang Yu Bowen Cheng +2 位作者 Zongling Li Weiwei Liu Luyuan Wang 《Journal of Data Analysis and Information Processing》 2019年第3期91-107,共17页
The design of reconfigurable multi-butterfly parallel radix-r FFT (Fast Fourier Transform) processors is proposed. FFT is widely used in signal processing, and the application needs real-time and high performance, whi... The design of reconfigurable multi-butterfly parallel radix-r FFT (Fast Fourier Transform) processors is proposed. FFT is widely used in signal processing, and the application needs real-time and high performance, while most of the traditional designs are limited to the power of two, which wastes the buffers and multipliers in big data. In response to the problem, we improve the parallel FFT algorithm with the design of reconfigurable control machine combined with buffer/multiplier, and the cost function with the input of radix/number/paddling number/time consuming is deduced. Constrained with the number of buffer and multipliers, the radix and number can be computed with the optimum cost function, and the resolution space of computing performance and hardware cost is presented. The proposed guarantees the real-time performance with better flexibility compared with the previous literature, and the comparison also suggests the effectiveness of the design. 展开更多
关键词 FFT RECONFIGURABLE multi-Butterfly PARALLEL processing
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Influence of a multi-step process on the thickness reduction error of sheet metal in a flexible rolling process
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作者 Yi Li Ming-zhe Li Kai Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2019年第1期76-85,共10页
Flexible rolling is a forming process based on thickness reduction, and the precision of thickness reduction is the key factor affecting bending deformation. The major purpose of the present work is to solve the probl... Flexible rolling is a forming process based on thickness reduction, and the precision of thickness reduction is the key factor affecting bending deformation. The major purpose of the present work is to solve the problem of bending deformation error caused by insufficient thickness reduction. Under the condition of different rolling reductions with the same sheet thickness and the same thickness reduction with different sheet thicknesses, the thickness reduction error of sheet metal is analyzed. In addition, the bending deformation of sheet metal under the same conditions is discussed and the influence of the multi-step forming process on the thickness reduction error is studied. The results show that, under the condition of the same sheet thickness, the thickness reduction error increases with increasing rolling reduction because of an increase in work hardening. As rolling reduction increases, the longitudinal bending deformation decreases because of the decrease of the maximum thickness difference. Under the condition with the same thickness reduction, the thickness reduction error increases because of the decrease of the rolling force with increasing sheet thickness. As the sheet thickness increases, the longitudinal bending deformation increases because of the increase in the maximum thickness difference. A larger bending deformation is divided into a number of small bending deformations in a multi-step forming process, avoiding a sharp increase in the degree of work hardening; the thickness reduction error is effectively reduced in the multi-step forming process. Numerical simulation results agree with the results of the forming experiments. 展开更多
关键词 FLEXIBLE rolling convex surface numerical simulation thickness REDUCTION ERROR multi-STEP forming process
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