测阻基本参数的测量方法

利用电磁踏板测量车辆的速度不仅是微机可控顶控制系统中的重要技术,而且在测阻中也起十分关键的作用,本文简要阐述了如何利用电磁踏板得到车辆的速度、加速度数据的实现方法和原理。

基于转盘测阻法的天然乳胶涂层减阻特性研究

利用转盘测阻法对天然乳胶涂层的减阻特性进行探究,确定雷诺数和柔性系数对涂层减阻效果的影响。利用喷涂法将天然乳胶和氨水混合溶液喷涂于转盘上,制成一种柔性涂层,并通过密度测定、硬度测定、力学性能测试和动态热力学分析等试验方法对涂层的物理性能与基本力学性能进行测定。试验结果显示,天然乳胶涂层密度为950 kg/m^(3),与水的密度接近,并且该涂层具有弹性模量低、撕裂强度大,断裂伸长率大的优点。采用转盘测阻法对涂层阻力进行测试,结果显示,当涂层厚度为0.2 mm、转速为100 r/min时达到最大减阻率15%,因此可断定天然乳胶涂层具有良好的物理机械性能,其减阻效果与水流状态及自身柔性存在一定关系,在特定情况下可实现良好的减阻效果。

风门负压法测阻解决采区通风问题研究——以淮河能源控股集团煤业分公司张集矿西翼采区为例

通过对矿井空气流动基本理论、通风管网风量与管网风阻管网风压及控风模式之间关系的研究,总结了深井开采通风阻力测量方法,提出了解决现代矿井安全生产中的通风系统问题的方法。结果表明,利用风门负压法测量通风阻力能够实现阻力的精准、快速测量,使阻力测量与矿井生产互不干扰,具有较高的应用价值。

曲线测阻的研究

货车溜放阻力是驼峰自动化车辆溜放速度自动控制的重要参数之一，对于点式控制系统的自动化驼峰尤为重要。从国外情况看，法国是在主减速器前设两个测速段，确定钩车阻力；美国多数自动化驼峰是在主减速器前设直线测阻区段。

电动机换向片间电阻检测设备的设计与实现

为提高直流电动机换向片片间电阻检测的效率和准确性,设计了一台由工控机、步进电动机传动系统、低电阻测量仪、上位机操作界面等组成的自动化检测设备。着重介绍了该设备的工作原理、步进电动机精确定位技术、四线测阻法、探针夹具的设计,以及基于LabWindows/CVI平台的软件界面开发技术。

利用风门测量巷道通风阻力

通过理论研究和探讨,推导出了利用风门不同开启程度时,测得的各并联巷道断面积和风量,计算巷道通风风阻和阻力的公式,简化了传统测量方法,解决了以往测通风阻力难的问题,并在辽源市某矿的四个采区实际应用中获得成功,与传统测阻方法相比较,相对误差均在2%以下。

埕北812A井组完井电测遇阻卡分析及对策

完井电测是整个钻井过程中的重要一环,是录取地质资料、了解地层结构、获得油气资源资料的方法和手段。胜利油田埕北油区埕北812A井组在完井电测施工中屡次出现遇阻、遇卡等问题,延长了建井周期,影响了经济效益。对完井电测遇阻卡的原因进行了分析并提出了对策,通过探索实践,与目的层位相同的CB32井组完井电测情况相比较,本井组复杂情况明显减少,取得了较好的效果。

谷物干燥水分在线测量系统设计

为了实现谷物干燥过程中水分值的精确控制,建立了一种适用于干燥机的谷物干燥水分在线测量系统。该系统基于电阻法测量原理,采用具有碾碎、挤压、测阻多重作用的螺旋式测阻机构采集信号,通过温度补偿与电路环境温度恒定相结合的方法避免温度对测量精度的影响,并以STC89C52单片机为核心完成数据采集、运算、显示及干燥机工作状态的控制。

检查电压调节器工作性能的几种方法

电压调节器按结构和工作原理一般可分为电磁振动式和电子式两大类。电磁振动式调节器按触点副数目不同可分为单极式（一对触点）和双极式（两对触点）；按组成结构不同又可分为单联式（结构中只有一个电压调节器）和双联式（结构中除有电压调节器外，还有一组辅助继电器，...

3D laterolog array sonde design and response simulation

A new three-dimensional laterolog array sonde（3D-LS） is presented. The 3DLS is based on existing high-resolution laterolog array and azimuthal resistivity imaging sondes with radial, longitudinal, and circumferential detection abilities. Six investigation modes are designed using the 3D finite-element method and different investigation depths are simulated based on the pseudo-geometrical factor of the six modes. The invasion profile is described using multi-array radial logs. From the analysis of the pseudo-geometrical factor, the investigation depth of the 3D-LS is about 1.5 m for conductive invasion, which is close to that of the dual laterolog tool but greater than that of the highly integrated azimuthal laterolog sonde. The vertical and azimuthal resolution is also analyzed with the same method. The 3DLS can detect low-resistivity anomalies of 0.5 m thickness and 15？ around the borehole for infinitely thick formations. This study lays the foundation for more work on 3D laterolog array sonde for evaluating low-resistivity anomalies.

Skin temperature measurement method

To improve the accuracy of skin temperature measurements in thermal comfort research,a new measurement method based on a new thermometer is proposed.A platinum film resistance（Pt1000）sensor of the thermometer is welded on a printed circuit board to eliminate the heat loss from the leads and avoid the influence of the surrounding thermal environment.In order to determine the suitable thickness of the board,a steady heat conduction model is established.The simulation results reveal that when the thickness of the board is 0.2 mm,the influence of the surrounding air can be effectively prevented and the skin temperature does not obviously increase.The experimental results of verification show that the maximum measurement error of the skin temperature measured by the thermometer is 0.24 ℃,and the average measurement error of the skin temperature is 0.04 ℃.The proposed method provides an effective and reliable option for the skin temperature measurement in thermal comfort research.

Pore structure effect on reservoir electrical properties and well logging evaluation

The reservoir pore structure controls the reservoir quality and resistivity response of hydrocarbon-bearing zones and thus, critically affects logging interpretation. We use petrophysical data in three types of reservoir with different pore structure characteristics to show that the complexity of pore structure had a significant effect on the effective porosity and permeability regardless of geological factors responsible for the formation of pore structure. Moreover,, the distribution and content of conductive fluids in the reservoir varies dramatically owing to pore structure differences, which also induces resistivity variations in reservoir rocks. Hence, the origin of low-resistivity hydrocarbon-bearing zones, except for those with conductive matrix and mud filtrate invasion, is attributed to the complexity of the pore structures. Consequently, reservoir-specific evaluation models, parameters, and criteria should be chosen for resistivity log interpretation to make a reliable evaluation of reservoir quality and fluids.

A method for testing drag-reduction on riblet surfaces based on the Spalding formula

This paper presents a method based on riblet surfaces. Its advantage lies in that it is more with testing methods using instruments such as a the Spalding formula for testing drag-reduction on convenient and yields more precise data compared scale. With this method, data is obtained from the velocity distribution within the inner layer, nearest the riblet surface. Precision of measurement of the velocity distribution is the key factor affecting the precision of the testing.

Improving Detectability of Resistive Shorts in FPGA Interconnects

The behavior of resistive short defects in FPGA interconnects is investigated through simulation and theoretical analysis.The results show that these defects result in timing failures and even Boolean faults for small defect resistance values.The best detection situations for large resistance defect happen when the path under test makes a v-to-v′ transition and another path causing short faults remains at value v.Small defects can be detected easily through static analysis.Under the best test situations,the effects of supply voltage and temperature on test results are evaluated.The results verify that lower voltage helps to improve detectability.If short material has positive temperature coefficient,low temperature is better;otherwise,high temperature is better.

Analysis and application of the response characteristics of DLL and LWD resistivity in horizontal well

There exist different response characteristics in the resistivity measurements of dual laterolog （DLL） and logging while drilling （LWD） electromagnetic wave propagation logging in highly deviated and horizontal wells due to the difference in their measuring principles. In this study, we first use the integral equation method simulated the response characteristics of LWD resistivity and use the three dimensional finite element method （3D-FEM） simulated the response characteristics of DLL resistivity in horizontal wells, and then analyzed the response differences between the DLL and LWD resistivity. The comparative analysis indicated that the response differences may be caused by different factors such as differences in the angle of instrument inclination, anisotropy, formation interface, and mud intrusion. In the interface, the curves of the LWD resistivity become sharp with increases in the deviation while those of the DLL resistivity gradually become smooth. Both curves are affected by the anisotropy although the effect on DLL resistivity is lower than the LWD resistivity. These differences aid in providing a reasonable explanation in the horizontal well. However, this can also simultaneously lead to false results. At the end of the study, we explain the effects of the differences in the interpretation of the horizontal well based on the results and actual data analysis.

漫话申桥

电桥,说穿了,就是一个平衡电路。它广泛地应用于仪器、仪表的检测及自动控制中。电桥的种类很多,如直流电桥有单臂电阻电桥、双臂电阻电桥;交流电桥有电容电桥、电感电桥。电容电桥可用于测量电容,电感电桥可用于测量电感。用得最多的算是直流电阻电桥,它除了可以准确地测量电阻外,还经常和其它一些附加电路组成各种温控。

The Segmentation of FMI Image Based on 2-D Dyadic Wavelet Transform

A key aspect in extracting quantitative information from FMI logs is to segment the FMI image to get images of pores, vugs and fractures. A segmentation method based on the dyadic wavelet transform in 2-D is introduced in this paper. The first step is to find all the edge pixels of the FMI image using the 2-D wavelet transform. The second step is to calculate a segmentation threshold based on the average value of the edge pixels. Field data processing examples show that sub-images of vugs and fractures can be correctly separated from original FMI data continuously and automatically along the depth axis. The image segmentation lays the foundation for in-situ parameter calculation.

Landslide monitoring in southwestern China via time-lapse electrical resistivity tomography

The dynamic monitoring of landslides in engineering geology has focused on the correlation among landslide stability,rainwater infiltration,and subsurface hydrogeology.However,the understanding of this complicated correlation is still poor and inadequate.Thus,in this study,we investigated a typical landslide in southwestern China via time-lapse electrical resistivity tomography（TLERT） in November 2013 and August 2014.We studied landslide mechanisms based on the spatiotemporal characteristics of surface water infiltration and flow within the landslide body.Combined with borehole data,inverted resistivity models accurately defined the interface between Quaternary sediments and bedrock.Preferential flow pathways attributed to fracture zones and fissures were also delineated.In addition,we found that surface water permeates through these pathways into the slipping mass and drains away as fissure water in the fractured bedrock,probably causing the weakly weathered layer to gradually soften and erode,eventually leading to a landslide.Clearly,TLERT dynamic monitoring can provide precursory information of critical sliding and can be used in landslide stability analysis and prediction.

Cycle life prediction and match detection in retired electric vehicle batteries

The lifespan models of commercial 18650-type lithium ion batteries （nominal capacity of 1150 mA-h） were presented. The lifespan was extrapolated based on this model. The results indicate that the relationship of capacity retention and cycle number can be expressed by Gaussian function. The selecting function and optimal precision were verified through actual match detection and a range of alternating current impedance testing. The cycle life model with high precision （〉99%） is beneficial to shortening the orediction time and cutting the prediction cost.

Experimental investigation on fatigue of blade specimen subjected to resonance and effect of a damping hard coating treatment

Failures due to high-cycle fatigue have led to a high cost in aerospace engineering over the past few decades.In this paper,the experimental results of the fatigue behavior of compressor blade specimen subjected to resonance and the effects of a damping hard coating on relieving the fatigue progress are presented.The crack initiation and propagation processes were observed under resonance of the first bending mode by using the resonant frequencies as the indicator.Significant nonlinear features were observed in the spectrum of the blade with a fatigue crack.The finite element model considering the breathing crack was established with nonlinear contact based on the crack localization and size,which was obtained by ultrasonic phased array technology.The simulation results of the vibration behavior of the cracked blade were obtained and consistent with the experimental results.A NiCrAlY coating was deposited on the blade,and increases in the fatigue life were observed under the same condition.The results of this paper can help to better understand the fatigue of a compressor blade subjected to resonance and provide a preference for the application of a damping hard coating on compressor blades.