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Generalized nth-Order Perturbation Method Based on Loop Subdivision Surface Boundary Element Method for Three-Dimensional Broadband Structural Acoustic Uncertainty Analysis
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作者 Ruijin Huo Qingxiang Pei +1 位作者 Xiaohui Yuan Yanming Xu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第8期2053-2077,共25页
In this paper,a generalized nth-order perturbation method based on the isogeometric boundary element method is proposed for the uncertainty analysis of broadband structural acoustic scattering problems.The Burton-Mill... In this paper,a generalized nth-order perturbation method based on the isogeometric boundary element method is proposed for the uncertainty analysis of broadband structural acoustic scattering problems.The Burton-Miller method is employed to solve the problem of non-unique solutions that may be encountered in the external acoustic field,and the nth-order discretization formulation of the boundary integral equation is derived.In addition,the computation of loop subdivision surfaces and the subdivision rules are introduced.In order to confirm the effectiveness of the algorithm,the computed results are contrasted and analyzed with the results under Monte Carlo simulations(MCs)through several numerical examples. 展开更多
关键词 Perturbation method loop subdivision surface isogeometric boundary element method uncertainty analysis
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Calculation of all-time apparent resistivity of large loop transient electromagnetic method with very fast simulated annealing 被引量:4
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作者 李建慧 朱自强 +2 位作者 冯德山 肖建平 彭凌星 《Journal of Central South University》 SCIE EI CAS 2011年第4期1235-1239,共5页
In large loop transient electromagnetic method(TEM),the late time apparent resistivity formula cannot truly reflect the geoelectric model,thus it needs to define the all-time apparent resistivity with the position inf... In large loop transient electromagnetic method(TEM),the late time apparent resistivity formula cannot truly reflect the geoelectric model,thus it needs to define the all-time apparent resistivity with the position information of measuring point.Utilizing very fast simulated annealing(VFSA) to fit the theoretical electromagnetic force(EMF) and measured EMF could obtain the all-time apparent resistivity of the measuring points in rectangular transmitting loop.The selective cope of initial model of VFSA could be confirmed by taking the late time apparent resistivity of transient electromagnetic method as the prior information.For verifying the correctness,the all-time apparent resistivities of the geoelectric models were calculated by VFSA and dichotomy,respectively.The results indicate that the relative differences of apparent resistivities calculated by these two methods are within 3%.The change of measuring point position has little influence on the tracing pattern of all-time apparent resistivity.The first branch of the curve of all-time apparent resistivity is close to the resistivity of the first layer medium and the last branch is close to the resistivity of the last layer medium,which proves the correctness of the arithmetics proposed. 展开更多
关键词 very fast simulated annealing (VFSA) large loop transient electromagnetic method rectangular loop all-time apparent resistivity
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Feasibility of central loop TEM method for prospecting multilayer water-fi lled goaf 被引量:9
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作者 Yan Shu Xue Gou-Qiang +2 位作者 Qiu Wei-Zhong Li Hai Zhong Hua-Sen 《Applied Geophysics》 SCIE CSCD 2016年第4期587-597,736,共12页
With deep mining of coal mines, prospecting multilayer water-filled goaf has become a new content that results from geophysical exploration in coalfields. The central loop transient electromagnetic (TEM) method is f... With deep mining of coal mines, prospecting multilayer water-filled goaf has become a new content that results from geophysical exploration in coalfields. The central loop transient electromagnetic (TEM) method is favorable for prospecting conductive layers because of the coupling relationship between its field structure and formation. However, the shielding effect of conductive overburden would not only require a longer observation time when prospecting the same depth but also weaken the anomalous response of underlying layers. Through direct time domain numerical simulation and horizontal layered earth forward modeling, this paper estimates the length of observation time required to prospect the target, and the distinguishable criterion of multilayer water-filled goal is presented with observation error according to the effect of noise on observation data. The observed emf curves from Dazigou Coal Mine, Shanxi Province can distinguish multilayer water-filled goaf. In quantitative inversion interpretation of observed curves, using electric logging data as initial parameters restrains the equivalence caused by coal formation thin layers. The deduced three-layer and two-layer water-filled goals are confirmed by the drilling hole. The result suggests that when observation time is long enough and with the anomalous situation of underlying layers being greater than the observation error, the use of the central loop TEM method to orosoect a multilaver water-filled goaf is feasible. 展开更多
关键词 central loop TEM method prospecting multilayer water-filled goaf conductive shielding layer numerical and theoretical analysis length of observation time observation error distinguishable criterion
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Study on the Coincident-Loop Transient Electromagnetic Method in Seafloor Exploration——Taking Jiaodong Polymetallic Mine as a Model 被引量:3
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作者 Yixing Ma Junhua Hu +1 位作者 Yanjun Chang Zujian Liu 《Journal of Earth Science》 SCIE CAS CSCD 2021年第1期25-41,共17页
The transient electromagnetic(TEM)method becomes more urgent than ever for marine ex-ploration due to abundant resource reserves and the increasing undersea engineering construction activities,especially in the offsho... The transient electromagnetic(TEM)method becomes more urgent than ever for marine ex-ploration due to abundant resource reserves and the increasing undersea engineering construction activities,especially in the offshore exploration of mineral deposits such as Sanshandao gold mine.However,the re-search and application of TEM method in marine environment are still challenged by many problems.Such contradiction motivates our study on the coincident-loop TEM in seafloor exploration.The TEM response of coincident loops is firstly derived in the integral form,based on the potential functions in Helmholtz equ-ations for a magnetic source locating in the whole-space layered model.The frequency-domain vertical magnetic field is described as the Hankel integral with double first-order Bessel functions of first kind.Se-condly,the time-domain induced voltage is obtained by transforming the frequency-domain response through the cosine transform and then taking the derivative of time.To simultaneously solve the Hankel transform and the cosine transform,a novel algorithm is introduced by adapting the fixed-point quadra-ture and extrapolation via the Shanks transformation.Finally,a typical conductivity model for marine po-lymetallic deposit is designed to investigate the characteristic of TEM response under various conditions.Numerical results demonstrate that existence of conductive seawater causes the TEM response to increase significantly and decay slower.The air-sea reflected electromagnetic waves lead to a significantly large fake negative response(NR)in shallower seawater with depth less than 300 m.Increase in the height of loops will weaken and delay the anomaly response and shorten the observation time-window.The height of configu-ration should be no more than 100 m for shallower targets and 50 m for deeper targets,respectively.The observation time-window should cover 10-1000 ms.Increase in the radius of loops only enhances the TEM response proportionally but hardly improves the relative anomaly.The vertical resolution on the low-resistivity target approximates 20 m for the configuration considered in the study.Decreases in D.C.resistivity and chargeability cause the positive response(PR)to increase significantly and decay more ra-pidly.Meanwhile,the NR is advanced and enlarged significantly and decays slower compared with the PR.The influence of time constant is not monotony and there exists an optimal value for producing the maxi-mum NR.As the frequency parameter increases,the PR is caused to decay more rapidly without magni-tude change and the NR is advanced and decays more rapidly with significant increase in magnitude.The influence of frequency parameter is more pronounced than that of time constant. 展开更多
关键词 marine transient electromagnetic method coincident loops induced polarization air-wave effects
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The Method for Measuring the Loop Resistance and the Temperature Rise Calculation of GIS Conductor Pole 被引量:1
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作者 Li Zhou Tiecheng Lu Bo Zhang 《Journal of Power and Energy Engineering》 2015年第4期306-312,共7页
This paper studies the method for measuring the loop resistance of GIS conductor pole based on the super capacitor producing impulse current up to several thousand amperes. This method overcomes the limitations of con... This paper studies the method for measuring the loop resistance of GIS conductor pole based on the super capacitor producing impulse current up to several thousand amperes. This method overcomes the limitations of conventional diagnostic method. Typical GIS conductor poles are chosen. Based on FEA and lab tests, the effect of different forms of current and contact condition, relationship between the temperature of contact and the loop resistance is researched. In full- scale testing under realistic operating conditions on the new 220 kV GIS using prototype instrumentation a very good sensitivity in an early stage was obtained. 展开更多
关键词 The method for MEASURING the loop Resistance and the Temperature RISE CALCULATION of GIS Conductor POLE
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Effectiveness of clip-and-snare method using pre-looping technique for gastric endoscopic submucosal dissection 被引量:10
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作者 Naohiro Yoshida Hisashi Doyama +5 位作者 Ryosuke Ota Yasuhito Takeda Hiroyoshi Nakanishi Kei Tominaga Shigetsugu Tsuji Kenichi Takemura 《World Journal of Gastrointestinal Endoscopy》 CAS 2016年第12期451-457,共7页
AIM:To evaluate efficacy and safety of clip-and-snare method using pre-looping technique(CSM-PLT)for gastric endoscopic submucosal dissection(ESD).METHODS:In the CSM-PLT method,a clip attached to the lesion side was s... AIM:To evaluate efficacy and safety of clip-and-snare method using pre-looping technique(CSM-PLT)for gastric endoscopic submucosal dissection(ESD).METHODS:In the CSM-PLT method,a clip attached to the lesion side was strangulated with a snare,followed by application of an appropriate tension to the lesion independent of an endoscope.Twenty consecutive lesions were resected by ESD using CSM-PLT(CSM-PLT group)and compared with a control group,including20 lesions that were resected by conventional ESD.The control group was matched based on the size and location of the lesion,presence of pathologic fibrosis,and experience of endoscopists.Total procedure time of ESD,proportion of en bloc resection,and complications were analyzed.RESULTS:The total procedure time for the CSM-PLT group was significantly shorter than that for the control group(38.5 min vs 59.5 min,P=0.023);all lesions were resected en bloc by ESD.There was no significant difference in complications between the two groups.Moreover,there was no complication in the CSM-PLT group.In one large lesion(size:74 mm)that underwentextensive CSM-PLT during ESD,we used an additional CSM-PLT on another edge of the lesion after achieving submucosal resection to the maximum extent possible during initial CSM-PLT.In two lesions,the snare came off the lesion together with the clip after a sudden pull;nevertheless,ESD was successful in all lesions.CONCLUSION:CSM-PLT was an effective and safe method for gastric ESD. 展开更多
关键词 Endoscopic submucosal DISSECTION Clipand-snare method Pre-looping TECHNIQUE Endoscope DISSECTION
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RUMINATE METHOD-SOFTWARE PIPELINING ON NESTED LOOPS
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作者 LEI WANG ZHIZHONGTANG and CHIHONG ZHANG(Dept. of Computer Science, Tsinghua Lirnivcrsitg Beijing 100084,P. R. China)(Final: wl,t ang ,zch@est4. dcs. tsinghua.edu. cn) 《Wuhan University Journal of Natural Sciences》 CAS 1996年第Z1期430-436,共7页
This paper offers a new method to solve the problem of software pipelininsr on nested loops. We first introduce our new software pipelininog method. Ruminate Method, which can optimize program with nested loops. We al... This paper offers a new method to solve the problem of software pipelininsr on nested loops. We first introduce our new software pipelininog method. Ruminate Method, which can optimize program with nested loops. We also outline an algorithm to realize it and introduce the hardware support we designed. The performance of Ruminate Method is analyzed at the end of this paper with the aid of our preliminary experimental result. 展开更多
关键词 Instruction-level Parallelism Software Pipeline Ruminate method Nested loop.
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Analyzing multi-circular loop scatterers by Maxwellian circuits
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作者 沈文辉 薛昌伟 +2 位作者 梅冠香 孟春香 林嘉宏 《Journal of Shanghai University(English Edition)》 CAS 2011年第1期54-57,共4页
Calculating the current distribution in circular loop scatterers commonly involves complicated computation. In this paper, based on the theory of Maxwellian circuits (MC), we propose a fast algorithm by solving a wa... Calculating the current distribution in circular loop scatterers commonly involves complicated computation. In this paper, based on the theory of Maxwellian circuits (MC), we propose a fast algorithm by solving a wave equation with constant parameters corresponding to the circular loop. Our method prodeces similar results compared to the methods using method of moments (MoM) with lower computational complexity. It is effective when there are parallel multiple circular loop scatterers. Experimental results show accuracy of the method. 展开更多
关键词 circular loop scatterer theory of Maxwellian circuits (MC) method of moments (MoM)
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EFFICIENT COMPUTATIONAL METHOD FOR TRANSIENT EM RESPONSE OF LARGE-LOOP SOURCE OVER LAYERED EARTH
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作者 Qi Youzheng Huang Ling +2 位作者 Zhao Haitao Fang Guangyou Yu Gang 《Journal of Electronics(China)》 2014年第3期187-192,共6页
Calculations of the ElectroMagnetic(EM) response produced by a large horizontal loop placed over layered medium are rather complex because its integral expression contains the product of two Bessel functions and has a... Calculations of the ElectroMagnetic(EM) response produced by a large horizontal loop placed over layered medium are rather complex because its integral expression contains the product of two Bessel functions and has a divergent term. In this paper, an improved fast Hankel and Gaver-Stehfest transforms are introduced to solve the strong-oscillation and slow-decay properties of the integrand, where one Bessel function in the product is substituted by a carefully chosen polynomial of high accuracy and the other used as the digital filter coefficients in the convolution integral. Comparisons prove the validity and the efficiency of the proposed method. 展开更多
关键词 Transient ElectroMagnetic(EM) method Circular loop Stratified earth Dual Bessel functions
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Radiating frequency of three-loop mesoscopic LC circuit with mutual inductance obtained by IEO method 被引量:1
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作者 Hong-yi Fan Ze Wu 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第8期99-102,共4页
Instead of normally tackling electric circuits by virtue oI the Klrctllaott's theorem wnose aim is to uerlvc voxt^gc, electric current, and electric impedence, our aim in this paper is to derive the characteristic fr... Instead of normally tackling electric circuits by virtue oI the Klrctllaott's theorem wnose aim is to uerlvc voxt^gc, electric current, and electric impedence, our aim in this paper is to derive the characteristic frequency of a three-loop mesoscopic LC circuit with three mutual inductances, e.g., for the radiating frequency of the three-loop LC oscillator, we adopt the invariant eigen-operator (lEO) method to realize our aim. 展开更多
关键词 IEO method three-loop LC mesoscopic circuit radiating frequency
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Hopping Parameter Expansion Technique in Noise Method for Disconnected Quark Loops
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作者 Jia-Liang Zhou Zhen Cheng +1 位作者 Guang-Yi Xiong Jian-Bo Zhang 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第4期16-19,共4页
We investigate the effectiveness of the hopping parameter expansion(HPE) combined with the Z(2) noise method in the calculation of the trace of the inverse of Wilson's Dirac operator and some other disconnected c... We investigate the effectiveness of the hopping parameter expansion(HPE) combined with the Z(2) noise method in the calculation of the trace of the inverse of Wilson's Dirac operator and some other disconnected contributions.A numerical comparison of the standard deviation for the Z(2) noise method and HPE with the Z(2) noise method is carried out. It is found that there are noise reductions in all the quantities we calculated using the HPE with the Z(2) noise method. For the trace of the inverse of Wilson's Dirac operator, the HPE can reduce the statistical error by about 60%. 展开更多
关键词 HPE Hopping Parameter Expansion Technique in Noise method for Disconnected Quark loops
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Three-Dimensional Phase Field Simulations of Hysteresis and Butterfly Loops by the Finite Volume Method
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作者 席丽莹 陈焕铭 +3 位作者 郑富 高华 童洋 马治 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第9期128-131,共4页
Three-dimensional simulations of ferroelectric hysteresis and butterfly loops are carried out based on solving the time dependent Ginzburg-Landau equations using a finite volume method. The influence of externally mec... Three-dimensional simulations of ferroelectric hysteresis and butterfly loops are carried out based on solving the time dependent Ginzburg-Landau equations using a finite volume method. The influence of externally mechanical loadings with a tensile strain and a compressive strain on the hysteresis and butterfly loops is studied numerically. Different from the traditional finite element and finite difference methods, the finite volume method is applicable to simulate the ferroelectric phase transitions and properties of ferroelectric materials even for more realistic and physical problems. 展开更多
关键词 Three-Dimensional Phase Field Simulations of Hysteresis and Butterfly loops by the Finite Volume method
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Rapid and Visualized Detection Method of Canine Parvovirus Using Loop-Mediated Isothermal Amplification
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作者 YANG Hui QU Guang-gang +1 位作者 ZHAO Yuan-kai SHEN Zhi-qiang 《Animal Husbandry and Feed Science》 CAS 2010年第1期34-37,共4页
[Objective] To develop a rapid and visualized detection method using loop-mediated isothermal amplification (LAMP), improve the detection rate of canine parvovirus (CPV) and reduce the testing cost. [ Method] Acco... [Objective] To develop a rapid and visualized detection method using loop-mediated isothermal amplification (LAMP), improve the detection rate of canine parvovirus (CPV) and reduce the testing cost. [ Method] According to the conserved regions of the VP2 gene of CPV, six primers were designed to amplify the special DNA sequences by LAMP. In addition, the reaction conditions of LAMP were optimized, and the sensitivity, specificity, repeatability and stability were verified. [ Result] The optimal reaction time of the LAMP method for CPVwas 60 min. The products obtained by LAMP had high specificity without cross-reaction with other generic viruses. The sensitivity of the LAMP was 100 times higher than that of PCR. [ Conclusion] The LAMP method for detecting CPV has high practical value. It has many advantages such as high specificity, high sensitivity, simple operation, low cost and rapid analysis, and it does not require special equipment. Therefore, this method is more suitable for the detection of CPV. 展开更多
关键词 Canine parvovirus loop-mediated isothermal amplification Diagnosis method
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Subsystem model-based close-loop grey-box identification method for hydraulic stewart platform
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作者 唐建林 董彦良 赵克定 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2011年第2期107-112,共6页
In order to solve the problem of difficult modeling and identification caused by time-variable parameters,multiple inputs and outputs and unstable open loop,a subsystem model-based close-loop grey-box identification m... In order to solve the problem of difficult modeling and identification caused by time-variable parameters,multiple inputs and outputs and unstable open loop,a subsystem model-based close-loop grey-box identification method was put forward when consider the main coupling effects of hydraulic Stewart platform.Firstly,the whole system is divided into three TITO(Two Input Two Output) subsystems according to the characteristics of the pseudo-mass matrix,hence transfer function matrix model of the subsystem can also be found.Secondly,since the Stewart platform is unstable,the close-loop transfer model of the subsystem is derived under the proportional controllers.The inverse M serial is adopted as the identification signal to get the experimental data.All parameters of the subsystem are determined in close-loop indirect identification by PEM(Prediction Error Method).Finally,a case study validates the correctness and effectiveness of the subsystem model-based close-loop grey-box identification method for hydraulic Stewart platform. 展开更多
关键词 hydraulic Stewart platform pseudo-mass matrix prediction error method close-loop indirect identification grey-box model
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跟网型逆变电源多回路耦合失稳机制分析
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作者 周一辰 徐宏伟 +3 位作者 李永刚 张艺菲 王子杰 李金泽 《中国电机工程学报》 北大核心 2025年第13期5226-5240,I0025,共16页
跟网型逆变电源控制系统内部回路间耦合复杂,参数影响导致系统失稳时,失稳参数影响的具体回路以及回路间作用机制尚不清楚。基于此,该文提出适用于分析跟网型逆变电源的嵌合转矩法,揭示参数影响下系统多回路耦合失稳机制。首先,建立跟... 跟网型逆变电源控制系统内部回路间耦合复杂,参数影响导致系统失稳时,失稳参数影响的具体回路以及回路间作用机制尚不清楚。基于此,该文提出适用于分析跟网型逆变电源的嵌合转矩法,揭示参数影响下系统多回路耦合失稳机制。首先,建立跟网型逆变电源各控制环节代数微分方程模型,同时,提出锁相环状态空间模型变换方法,形成适用于转矩分析法的2阶微分方程结构;其次,建立保留回路结构的嵌合转矩拓扑图,推导跟网型逆变电源各回路所提供阻尼转矩的计算公式;然后,提出跟网型逆变电源回路间互激、竞争理论,设计参数影响回路溯源方法;最后,溯源关键参数影响下的回路间互激、竞争路径,揭示逆变电源多回路耦合的失稳机制。 展开更多
关键词 跟网型逆变电源 多回路耦合 嵌合转矩法 溯源路径 互激竞争 失稳机制
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地面瞬变电磁法对覆盖层下低阻金属脉状矿体分辨能力探究 被引量:1
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作者 王扬州 邢涛 +2 位作者 于景邨 王垚 李建慧 《地球物理学进展》 北大核心 2025年第4期1473-1491,共19页
脉状矿体是金属硫化物的重要载体,通常具有低电阻率的特征.目前,瞬变电磁法已广泛应用于探测低阻脉状矿体,而正演响应研究是野外数据采集方案设计、室内资料处理解释的基础.为优化野外勘探方案和合理解释实测数据,本文构建了赋存于覆盖... 脉状矿体是金属硫化物的重要载体,通常具有低电阻率的特征.目前,瞬变电磁法已广泛应用于探测低阻脉状矿体,而正演响应研究是野外数据采集方案设计、室内资料处理解释的基础.为优化野外勘探方案和合理解释实测数据,本文构建了赋存于覆盖层下低阻脉状矿体模型,利用矢量有限元三维正演方法,系统探讨了发射回线尺度,覆盖层电导率和厚度,矿体电导率、厚度和倾角等因素对瞬变电磁法分辨能力影响规律.计算结果表明:发射回线尺度增大使得感应电动势总场增强,但感应电动势总场与背景场比值降低,即分辨能力下降.以构建的模型作为算例,发射回线边长增大3倍,分辨能力降低7/9.覆盖层电导率和厚度的增加、矿体电导率和厚度的降低均显著削弱瞬变电磁法分辨能力.当发射回线边长为300 m,覆盖层电导率增加10倍,分辨能力降低94.5%;覆盖层厚度增加2.5倍,分辨能力降低96.7%;脉状矿体电导率降低49/50;分辨能力降低98.8%;脉状矿体厚度降低9/10,分辨能力降低96.7%.脉状矿体倾角的增加会改变分辨能力最强测点的位置.比如,当脉状矿体倾角为25°时,矿体中心对应测点分辨能力最强;当脉状矿体倾角为75°时,矿体较深的一端对应测点分辨能力最强.研究表明,覆盖层和矿体的物性参数显著影响瞬变电磁法对脉状矿体的分辨能力,尤其在采用小尺度发射回线时影响更为显著.因此,在设计方案时需要权衡发射回线尺度、分辨能力、目标体大致范围和施工效率等要素. 展开更多
关键词 瞬变电磁法 脉状矿体 分辨能力 发射回线尺度 覆盖层
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基于改进SMO的PMSM无位置传感器控制 被引量:1
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作者 陈甦欣 蒋曜骏 +1 位作者 王淑旺 侯陈义 《组合机床与自动化加工技术》 北大核心 2025年第2期148-152,共5页
传统滑模观测器(SMO)在估算电机转速和转子位置时存在抖振较强以及转速误差波动较大等问题,为解决以上问题,引入了一种改进型指数趋近律,并且用光滑的双曲正切函数代替传统的符号函数,降低了系统的高频抖振;采用积分滑模面代替传统的滑... 传统滑模观测器(SMO)在估算电机转速和转子位置时存在抖振较强以及转速误差波动较大等问题,为解决以上问题,引入了一种改进型指数趋近律,并且用光滑的双曲正切函数代替传统的符号函数,降低了系统的高频抖振;采用积分滑模面代替传统的滑模面,消除了定子电阻的影响,并用Lyapunov第二方法证明了该方法的稳定性;最后,为了保证电机运行时有较高的观测精度,通过改进锁相环代替反正切函数和相位补偿。并基于Simulink搭建仿真模型来验证可行性,经仿真对比分析,本文设计的观测器在转速突变和加入负载后转速误差范围从-10 r/min~10 r/min降低至-0.1 r/min~0.4 r/min,转子位置误差降低了44.4%。表明了设计的观测器具有良好的动态响应性能,并且能有效地降低高频抖振,提高了观测精度,具有较好的鲁棒性。 展开更多
关键词 永磁同步电机 无位置传感器 滑模观测器 指数趋近律方法 锁相环(PLL)
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基于规范形方法的并网变换器系统暂态同步稳定分析
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作者 刘其辉 李开心 +2 位作者 蔡希鹏 朱益华 罗超 《电力自动化设备》 北大核心 2025年第6期116-123,共8页
锁相环(PLL)在电压源型变换器(VSC)并网系统中的非线性动力学特性,给新型电力系统的暂态同步稳定性分析带来了挑战,特别是在强非线性系统中。为此,针对具有较强非线性PLL的VSC并网系统,建立其暂态响应的2阶微分方程,并基于规范形方法推... 锁相环(PLL)在电压源型变换器(VSC)并网系统中的非线性动力学特性,给新型电力系统的暂态同步稳定性分析带来了挑战,特别是在强非线性系统中。为此,针对具有较强非线性PLL的VSC并网系统,建立其暂态响应的2阶微分方程,并基于规范形方法推导PLL输出相位的解析解。在此基础上,分析系统的同步稳定机理,提出新的暂态稳定判据,揭示影响暂态同步稳定性的关键因素及规律。研究结果表明,VSC有功出力、电网电感、PLL的比例积分参数是影响暂态同步稳定性的主要因素。基于MATLAB/Simulink进行仿真与实验以验证所提方法的有效性,结果表明该方法能够提高电力系统暂态稳定性分析的准确性与可靠性。 展开更多
关键词 并网变换器 非线性分析 规范形方法 锁相环 暂态同步稳定性
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直驱风电并网系统暂态稳定域研究
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作者 严干贵 张皓程 +2 位作者 岳霖 杨成 李永越 《东北电力大学学报》 2025年第3期19-29,共11页
风电并网系统依赖锁相环保持与系统的同步运行,并实现有功、无功的解耦控制,大扰动下锁相环极易受到并网点电压的影响,导致风电机组失步脱网。首先建立直驱风电并网系统在暂态期间的等效转子运动方程,刻画并分析了其同步特性;然后类比... 风电并网系统依赖锁相环保持与系统的同步运行,并实现有功、无功的解耦控制,大扰动下锁相环极易受到并网点电压的影响,导致风电机组失步脱网。首先建立直驱风电并网系统在暂态期间的等效转子运动方程,刻画并分析了其同步特性;然后类比传统同步发电机的功角稳定理论,分析在一定初始状态及故障强度下,系统暂态稳定平衡点的存在性问题,在此基础上,基于电网故障期间有功、无功电流注入的暂态稳定域,对稳定域中的一系列特征点进行详细分析,为不同目的导向的稳定控制策略提供设计依据;最后在PSCAD平台上搭建直驱风电并网系统的仿真模型,量化分析在对应特征点取值的有功、无功电流注入下系统的暂态特性,相关仿真案例验证理论分析及所提出的暂态稳定域的合理性。 展开更多
关键词 直驱风电 锁相环 暂态稳定性 等面积法 暂态稳定域
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基于车牌识别数据的交通信号控制研究综述
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作者 李瑞敏 黄杰辉 刘一霖 《大连交通大学学报》 2025年第5期1-11,共11页
基于视频检测器获取的车牌识别数据具有抽样率高、覆盖广泛、蕴含多种动静态交通状态信息的特点,对近20年国内外基于车牌识别数据优化交通信号控制的相关研究进行系统性梳理与分析。研究显示:车牌识别数据可支持行程时间、交通流量、排... 基于视频检测器获取的车牌识别数据具有抽样率高、覆盖广泛、蕴含多种动静态交通状态信息的特点,对近20年国内外基于车牌识别数据优化交通信号控制的相关研究进行系统性梳理与分析。研究显示:车牌识别数据可支持行程时间、交通流量、排队长度等多类交通状态参数的估计,不仅可为交通信号控制优化(如配时优化、子区划分等)提供决策支持,还可为信号配时优化方案的实施提供实时的评价反馈。目前,车牌识别数据在信号控制优化领域主要支撑交通信号配时优化、信号控制子区划分、信号控制评价3个方面,但其在“分析—优化—评价”闭环反馈机制中的潜在价值和信息能力尚未被充分挖掘。未来可进一步探索以下方面:车牌识别数据与智能网联轨迹数据的创新融合可能性,强化学习、混合学习、大模型等新技术的应用,信号控制优化的新方向拓展,以及开发面向车牌识别数据的控制与仿真建模方法等。上述研究旨在为车牌识别数据在交通信号控制领域的更深度应用提供借鉴。 展开更多
关键词 车牌识别 交通状态参数估计 交通信号控制 闭环反馈机制 方法与模型
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