Calculation of all-time apparent resistivity of large loop transient electromagnetic method with very fast simulated annealing

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.

Effectiveness of clip-and-snare method using pre-looping technique for gastric endoscopic submucosal dissection

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.

Radiating frequency of three-loop mesoscopic LC circuit with mutual inductance obtained by IEO method

Instead of normally tackling electric circuits by virtue of the Kirchhoff's theorem whose aim is to derive voltage,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(IEO) method to realize our aim.

The Method for Measuring the Loop Resistance and the Temperature Rise Calculation of GIS Conductor Pole

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.

RUMINATE METHOD-SOFTWARE PIPELINING ON NESTED LOOPS

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Rapid and Visualized Detection Method of Canine Parvovirus Using Loop-Mediated Isothermal Amplification

[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 CPV was 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.

EFFICIENT COMPUTATIONAL METHOD FOR TRANSIENT EM RESPONSE OF LARGE-LOOP SOURCE OVER LAYERED EARTH

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.

Subsystem model-based close-loop grey-box identification method for hydraulic stewart platform

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.

系统动力学反馈环快速计算法研究

针对系统动力学传统枝向量行列式反馈环计算法存在计算时花费时间过长、计算结果容易出错且难以检验等问题,提出了系统动力学反馈环快速计算法。该方法借助Vensim软件Loops功能,以各流位变量为起点生成系统反馈回路集,再删除重复反馈环,可得到此系统所有非重复反馈环集合。以萍乡明鑫农场“基地+农户”供应链复杂系统为例,借助已构建的11棵强简化流率基本入树模型,分别用行列式计算法和该方法计算得出该系统所有反馈环。研究表明,两种方法最终计算结果相同,但反馈环快速计算法却能大大节省计算时间,并提高计算准确率。并可基于此深入分析系统结构,以期提出相对应的管理对策。

机织钩面粘扣带表面质量的机器视觉检测方法

针对机织钩面粘扣带表面质量人工检测中存在的精度低等问题,提出了基于机器视觉的机织钩面粘扣带表面质量检测方法。通过单目视觉的切向成像获得粘扣带表面的单行图像,避免了粘扣带相邻行之间的干扰。对单行粘扣带图像进行预处理后,采用投影法对其进行水平投影和垂直投影,提取粘扣带表面单行图像中的每个钩扣状区域,基于连通域统计法判别钩扣状区域的切割状态,计算其切开率,通过统计数据表征粘扣带表面质量。实验结果表明,该方法对机织钩面粘扣带表面质量的检测相对误差为1%,具有较高的稳定性。

基于多导体回路法的AT供电方式长回路电容计算方法研究

提出了一种基于多导体回路法以接触网和正馈线为传输导体的电气化铁路AT供电方式牵引网长回路电容计算方法。该方法以与电荷唯一对应的回路为基本单元,对复杂多导体传输线系统开展电场描述,实现了AT供电方式牵引网长回路电容的精确计算。

大定源回线装置瞬变电磁法在煤矿采空区探测中的应用

该文通过研究大定源回线装置瞬变电磁法在煤矿采空区探测中的应用,旨在提高煤矿采空区探测的效率和准确性。深入探讨大定源回线装置瞬变电磁法的原理和工作机制。在此基础上,设计并实施适用于煤矿采空区的探测方案,并通过试验进行验证。结果表明,大定源回线装置瞬变电磁法在煤矿采空区探测中取得显著的效果。大定源回线装置瞬变电磁法具有高效、准确、可靠的特点,能够快速识别采空区位置,为后续生产建设提供保障,同时也为其他煤矿采空区勘察提供参考。

基于区段的地下空间环路通风排烟设计方法

为实现多匝道、多地块、内部空间复杂的地下空间环路烟气控制,提出一种区段式排烟方法:将地下空间环路与地块通过防火门分隔,形成独立的构筑物,结合隧道结构,确定风机房位置,划分区段,使烟气在一定区域内排出。以滨江地下环路为例,在隧道主线上均匀布置6个排烟风机房,并以此为节点,将隧道划分为8个区段。当火灾发生时,开启所在区段两端的风机进行排烟。由于各区段不设置固定分隔,整个风道是贯通的,因而各个风机房里的风机可互相作为备用排烟风机,以降低成本。采用数值模拟软件建立模型,对排烟口开启数量和间距进行模拟,确定排烟量为90 m^(3)/s、排烟口间距为30 m、开启8个排烟口的排烟方案。从人员疏散环境以及排烟效率对典型区段进行分析,结果表明:烟气控制在一定的范围内,人员疏散环境安全,排烟效率达到90%,证明方案合理可行。

X-in-the-loop方法在燃料电池汽车动力系统测试上的应用

针对燃料电池汽车动力系统测试难以完全满足开发测试要求的现状,以及难以实现软硬件结合测试的特点,引入X-in-the-loop开发测试验证方法,并基于该方法开发了一套燃料电池汽车动力系统动态性能综合测试平台,可实现模型在环、软件在环和硬件在环等针对不同类型测试对象的匹配和性能测试。利用X-in-the-Loop方法进行燃料电池汽车动力系统及其关键部件的开发测试,可明显提高测试验证的效率,缩短时间,降低成本。

基于回路风量法的矿井通风网络解算算法

基于当前矿井通风网络解算算法的不足,深入研究回路法、Scott-Hinsley和Seidel法,设计出一种能够快速解算复杂风网的算法,主要步骤包括确定风网结构、赋权边并选取最小生成树、圈划独立回路、进行网络解算。该方法用Kruskal法来选取最小生成树,思路清晰、易于理解,方便计算机程序的实现;用试探回溯法来圈划独立回路,对于反复出现的子问题,无需进行二次求解;用改进Scott-Hinsley法进行风量解算,计算收敛速度更快,提高了算法的执行效率。将该优化算法应用于“黄坊煤矿通风智能决策系统”迭代解算模块。结果表明:风量解算结果与实测值误差均小于5%,能满足工程应用要求,为矿井通风网络解算提供了一种新思路。

3轨式横向对称分布6-PSS并联机构及性能优化

针对多滑块共轨式6-PSS并联机构存在的姿态工作空间小、容易奇异等问题,课题组提出一种3轨式分布的6-PSS并联机构(P为移动副,S为球副)。该并联机构杆件长度和轨道间距呈不均匀布置,以提升姿态工作空间;采用闭环矢量法进行位置分析,通过极限边界搜索法求解工作空间;基于运动/力传递指标对机构性能进行评估,并采用性能图谱法基于全域指标GTI进行机构尺寸优化。结果表明优化后机构运动/力传递性能有显著提升,同时姿态工作空间也得到提升。该机构在工程上有一定的实用性。

双差模非屏蔽线缆回路的电磁串扰研究

随着电气化的发展,电气与电子系统中的电磁兼容问题越来越被重视,为了消除或抑制电磁耦合的影响,实现设备或元件电磁兼容的工作,有必要对线缆间的串扰进行研究。但目前少有相关研究关注独立的发射回路与接收回路构成的双差模回路间的电磁串扰问题。提出了一种基于多导体传输线理论的五导体传输线模型,并基于此研究了双差模非屏蔽线缆回路间的串扰问题。该方法根据耦合机理,首先建立单位长度五导体传输线等效模型,然后根据有限差分的方法列写基尔霍夫方程组,最后补充边界条件后求解得到串扰的频域解。将串扰计算结果与CST软件仿真结果进行对比,验证了该模型和计算方法的可行性与有效性,经计算分别研究了感性耦合与容性耦合,分析得到了不同因素对线束间串扰的影响规律,可为实际工程中采取措施抑制线缆间串扰提供指导,体现出该模型的先进性。

LOOP环改良法全自动化制备^(11)C-胆碱

为研究国产^(11)C-多功能合成模块经LOOP环法合成放射性药物[N-甲基-^(11)C]胆碱(^(11)C-Choline,^(11)C-CH)的合成方法,对碱当量、溶剂效应及前体量等影响因素进行研究,优化LOOP环法合成^(11)C-CH的合成工艺。^(11)C-CH的优化条件:前体量为60~150 uL,无碱无溶剂,室温与^(11)C-CH 3I反应。此条件下^(11)C-CH的合成效率为(72.16±2.96)%(n=19,^(11)C-CH 3I未校正效率),产品的放化纯度均大于95%,产量为(7.59±1.54)GBq(n=19)。国产^(11)C-多功能合成模块LOOP环法合成^(11)C-CH与C18柱固相法进行比较表明,LOOP环可以多次重复利用,降低生产成本,提高合成效率,实现稳定、全自动化合成^(11)C-CH,产品满足临床需求。

高温环路热管设计方法研究与传热极限分析

高超声速飞行器在以高超声速飞行时尾喷管会面临严酷的燃烧热考验,结合高温热管导热性强和环路热管传热距离长等优势,高温环路热管可以作为尾喷管热防护的新方法.根据液态钠高导热系数及高表面张力的物性设计了一种新型蒸发器,提出了一套高温环路热管的设计流程.使用这套设计流程设计了一根高温环路热管,结合热管传热极限的计算方法,对钠热管进行仿真计算,分析了温度和结构对热管传热极限的影响.研究发现在高温环路热管的运行温区内,热管的传热性能随着温度升高一般由声速极限、毛细极限和沸腾极限依次决定.结合研究结论提出了热管结构优化方法,为热管设计提供了理论依据.

综合电磁法在凤太二里河铅锌矿深部的找矿效果分析

二里河铅锌矿是凤太矿集区中具有代表性的重要铅锌矿床之一,近些年找矿方向转向已知矿体深部及外围。根据二里河地区地质、地球物理特征,结合多年在凤太地区的综合地球物理找矿工作,分析了回线源瞬变电磁法、电性源短偏移距瞬变电磁法及广域电磁法在二里河地区的实际应用效果,对3种方法的特点和适用性进行总结,认为:回线源瞬变电磁法、电性源短偏移距瞬变电磁法及广域电磁法在该地区深部找矿具有可行性;回线源瞬变电磁法对于圈定矿体水平位置具有较好的效果,电性源短偏移距瞬变电磁法对低阻异常较为敏感,广域电磁法分辨率较高,同时探测深度可达到2500 m。此外针对二里河矿区的找矿工作,提出物探工作建议:采用以广域电磁法和电性源短偏移距瞬变电磁法为首选的综合电磁探测方法,同时应尽可能采用长剖面和面积性物探工作。