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1.
在近10余年观测研究的基础上，采用高精度MMSO2E系统，在青藏高原北缘祁连山地震危险区，建立了国内外第一个初具规模的MT透视剖面，研究区不仅电磁干扰背景较弱，而且地震活动性较强，自1986年以来，我们已经获得了11次5－7级地震前后的宝贵资料，在研究这些资料的基础上，提出了一些有意义的认识和结论，对观测资料进行了全定量化的误差分析，评估了MT响应参数和复合二元相关度和可信限，论述了MT剖面透视资料的可靠性和可信性，对介质导电性和电性横向非均匀性动态变化的原因进行了讨论，研究表明，MT剖面透社为大陆坡坏地性地震的中短期预测及震源物理发展过程提供了定量化的多参数指标体系。 相似文献
2.
The application of pulse EM and MAXMIN II systems in search of a kimberlite diatremes under conducting cover has been demonstrated through a field example. The effectiveness of the PEM system in the search for conductive zones of economic importance and in discrimination against geologic noise such as overburden has been investigated. The transient observation has been transformed to equivalent half-space resistivities at various times. The feasibility of mapping thin conducting overburden using the PEM system has been studied by inverting the transient measurement to the thin infinite horizontal sheet conductance. The PEM measurement is shown to be an economic and effective tool for shallow geoelectric mapping. 相似文献
3.
A KEY TECHNOLOGY FOR MONITORING STRESS BY TEMPERATURE: MULTICHANNEL TEMPERATURE MEASUREMENT SYSTEM WITH HIGH PRECISION AND LOW POWER CONSUMPTION 
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下载免费PDF全文 Experimental and theoretical researches have confirmed that changes in crustal stress can be monitored by the in situ bedrock temperature. Monitoring stress by temperature requires the high-precision and multi-channel temperature measurement system. We have developed such a system, based on the several refinements. The key parameters on temperature measurement system mainly include:1)the accuracy is better than 1.0mK. At the 99.5%confidence level, the accuracy reaches 0.5mK. This system can be used to detect the change of magnitude of a few tenths to several MPa. The sampling period can be set, depending on remote control. The sampling period is usually set 5 or 15 minutes. 2)A system has up to 20 channels, and commonly uses for 8 or 12 channels. 3)This system has a significant performance in low power consumption. The power is supplied by lead-acid battery with 12 volt. It is at least 2 years that a lead-acid battery, with contents of 120Ah12V, can supply the power for a system with 8 channels. In conclusion, multichannel temperature measurement system with high precision and low power consumption is designed and realized. Specially, the performance in low power consumption is of great significance, which can greatly reduce the maintenance cost after the measurement station is constructed. This temperature measurement system provides a basic technology for monitoring changes in crustal stress with bedrock temperature. 相似文献
4.
The Russian electrodynamic seismometer model S-5-S has been adapted for the measurement of rotational ground motion. The mechanical system of the original S-5-S seismometer consists of electrodynamic sensing and damping transducer coils mounted on an asymmetrical double-arm pendulum. This pendulum is suspended on a footing using two pairs of crossed flat springs, which operate as the axis of rotation. The pendulum is stabilised by an additional spring. The S-5-S can be used either as a vertical or as a horizontal sensor. The adaptation of the S-5-S seismometer described below involves removal of the additional spring and installation of an additional mass on the damping arm. Strain gauge angle sensors are installed on one pair of the crossed flat springs. The main dynamic parameters of the rotational seismometer created in this way, i.e. the natural period and damping, are controlled electronically by feedback currents proportional to the angular displacement and angular velocity, both fed to the damping transducer coil. This new seismometer, named the S-5-SR, enables measurement of the rotational component of ground motion around the horizontal or the vertical axes. The output signal from this S-5-SR seismometer can be proportional either to rotational displacement or rotational velocity. 相似文献
5.
6.
MICROMETER SCALE MORPHOLOGY MEASUREMENT SYSTEM: A NEW TECHNIQUE FOR MICRO-TOPOGRAPHY MEASUREMENT ON FAULT PLANES 下载免费PDF全文
下载免费PDF全文 Earthquakes commonly occur in the sliding surface of the fault zone. The morphology of the sliding surface is the result of fault activities, and also it evolves with the activities. The irregular geometry of the fault plane affects the sliding resistance, the concentration and anisotropy of the stress distribution within the fault plane and the fault shear strength. So, the acquisition of high-precision morphological features is of great significance for studying the correlation between fault surface morphology and seismic nucleation, fracture propagation and termination. Due to the lack of reliable micron-scale morphological measurement apparatus, the study of the coherence of the fault surface morphology from large scale(unit: m-cm)to small scale(unit: μm)is subject to restrictions, as well as the study of the relationship between the micro-morphology of the experimental frictional surface and the rupture process. In order to improve the measurement accuracy of the fault plane and overcome the shortcomings of existing measurement methods, we have invented a morphology measurement system with independent intellectual property rights.
The measuring principle of this morphology measurement system is based on the laser rangefinder theory. The frame of this system consists of four parts: Braced Frame, Moving Scanner Unit, System-Controlling Unit and Data Collection Unit. Braced Frame is made up of high-adjustable frame, loading stage, dust-proof box and isolation platform, which is used to provide a vibration isolation, light proof and dust-proof measuring environment. Moving Scanner Unit contains a laser head and a two-dimensional translation stag, the laser head is used to measure vertical distance and a two-dimensional translation stage carrying a laser head moving in X-axis and Y-axis orientation to provide X, Y coordinate values. System-Controlling Unit includes two-dimensional translation stage controller, laser head controller and signal convertor. The function of this part is mainly to control operation of other parts. The Data Collection Unit is composed of computer system and software module. This part connects other parts for receiving and storing data. In order to improve the scan efficiency, we developed new software by which we can precisely control the measuring process and efficiently process the acquired data. The software is comprised of five modules: 1)Move Module, this module is used to control the original moving of the laser head relative to the two-dimension translation stage and display the 3-dimensional coordinate information in real time; 2)Set Parameters of Scan Area, the function of this module is to obtain the XY coordinate values of four corner points of the target area to scan; 3)Scan Method Module, though this part, we can control the point spacing in the X-axis orientation by inputting velocity of laser header, as well as the point spacing in X-axis orientation by inputting the Y-step parameter; 4)Pre-Scan Module, there are three functions in this module to inspect whether the z-value of the target area is beyond the range of the laser head or not, estimate consuming time for scanning the object area under the predefined parameters and to estimate the size of the result file; and 5)Scan Module, the function of this module is to store the scanning data.
We scanned the camera lens and the standard plate whose standard deviations are lower than 5μm to acquire the precision of the measurement system, and the results show that the precision of the plane positioning (X-axis and Y-axis direction)is better than 3.5μm; the vertical measurement precision is better than 4.5μm. The highest resolution of the measurement system is constrained by the performance of the laser head and two-dimension translation stage, and the horizontal resolution can reach 0.62μm, vertical resolution 0.25μm. When the needed resolution is lower than the highest, we can achieve it through adjusting the parameter of the velocity in the X-axis orientation and steps in the Y-axis orientation. To test the practical effect of the measurement system, we scanned an area of frictional surface of experimental rock using this system and obtained a high-resolution topography data. From the DEM interpolated from the cloud data, we can observe the striation on the fault plane and the variation of the roughness distribution. The roughness and slope distribution results show that the topography measurement system can meet our requirements for analyzing the microscopic morphology on the micrometer scale.
Compared with traditional measurement devices, the morphology measurement system has the following advantages: 1)The measurement system can obtain the data even in a valley region with a large dip angle on the surface because the vertically emitted beam by the laser head is practically perpendicular to the surface. So compared with other means, it can avoid producing a blank area of measurements and get a complete area; 2)the measurement system has a larger measurement range of 30cm×30cm. When the high-resolution measurement is performed on a large scale, the error caused by the registration of multiple measurement results can also be avoided. 相似文献
The measuring principle of this morphology measurement system is based on the laser rangefinder theory. The frame of this system consists of four parts: Braced Frame, Moving Scanner Unit, System-Controlling Unit and Data Collection Unit. Braced Frame is made up of high-adjustable frame, loading stage, dust-proof box and isolation platform, which is used to provide a vibration isolation, light proof and dust-proof measuring environment. Moving Scanner Unit contains a laser head and a two-dimensional translation stag, the laser head is used to measure vertical distance and a two-dimensional translation stage carrying a laser head moving in X-axis and Y-axis orientation to provide X, Y coordinate values. System-Controlling Unit includes two-dimensional translation stage controller, laser head controller and signal convertor. The function of this part is mainly to control operation of other parts. The Data Collection Unit is composed of computer system and software module. This part connects other parts for receiving and storing data. In order to improve the scan efficiency, we developed new software by which we can precisely control the measuring process and efficiently process the acquired data. The software is comprised of five modules: 1)Move Module, this module is used to control the original moving of the laser head relative to the two-dimension translation stage and display the 3-dimensional coordinate information in real time; 2)Set Parameters of Scan Area, the function of this module is to obtain the XY coordinate values of four corner points of the target area to scan; 3)Scan Method Module, though this part, we can control the point spacing in the X-axis orientation by inputting velocity of laser header, as well as the point spacing in X-axis orientation by inputting the Y-step parameter; 4)Pre-Scan Module, there are three functions in this module to inspect whether the z-value of the target area is beyond the range of the laser head or not, estimate consuming time for scanning the object area under the predefined parameters and to estimate the size of the result file; and 5)Scan Module, the function of this module is to store the scanning data.
We scanned the camera lens and the standard plate whose standard deviations are lower than 5μm to acquire the precision of the measurement system, and the results show that the precision of the plane positioning (X-axis and Y-axis direction)is better than 3.5μm; the vertical measurement precision is better than 4.5μm. The highest resolution of the measurement system is constrained by the performance of the laser head and two-dimension translation stage, and the horizontal resolution can reach 0.62μm, vertical resolution 0.25μm. When the needed resolution is lower than the highest, we can achieve it through adjusting the parameter of the velocity in the X-axis orientation and steps in the Y-axis orientation. To test the practical effect of the measurement system, we scanned an area of frictional surface of experimental rock using this system and obtained a high-resolution topography data. From the DEM interpolated from the cloud data, we can observe the striation on the fault plane and the variation of the roughness distribution. The roughness and slope distribution results show that the topography measurement system can meet our requirements for analyzing the microscopic morphology on the micrometer scale.
Compared with traditional measurement devices, the morphology measurement system has the following advantages: 1)The measurement system can obtain the data even in a valley region with a large dip angle on the surface because the vertically emitted beam by the laser head is practically perpendicular to the surface. So compared with other means, it can avoid producing a blank area of measurements and get a complete area; 2)the measurement system has a larger measurement range of 30cm×30cm. When the high-resolution measurement is performed on a large scale, the error caused by the registration of multiple measurement results can also be avoided. 相似文献
7.
A laboratory sensor has now been developed to measure the absolute thickness of oil on water slicks. This prototype oil slick thickness measurement system is known as the laser-ultrasonic remote sensing of oil thickness (LURSOT) sensor. This laser opto-acoustic sensor is the initial step in the ultimate goal of providing an airborne sensor with the ability to remotely measure oil-on-water slick thickness. The LURSOT sensor employs three lasers to produce and measure the time-of-flight of ultrasonic waves in oil and hence provide a direct measurement of oil slick thickness. The successful application of this technology to the measurement of oil slick thickness will benefit the scientific community as a whole by providing information about the dynamics of oil slick spreading and the spill responder by providing a measurement of the effectiveness of spill countermeasures such as dispersant application and in situ burning.
This paper will provide a review of early developments and discuss the current state-of-the-art in the field of oil slick thickness measurement. 相似文献
8.
一个基于扫频与混频相结合的多频EIT数据采集系统 总被引：1，自引：0，他引：1
采用多频率组合与扫频技术相结合的方式,建立了一个32电极多频电阻抗断层成像数据采集系统,该系统具有四种工作模式,在程序控制下,最多步采集四种频率下的组织阻抗信息,工作频率可在1．6KHZ到380KHZ间程控选择。为从含多种频率分量的测量信号中解调出各频率下的组织阻抗,我们设计了一种新的具有高速和高精度特点的解调方法,正交序列数字解调法,对含有n个频率分别的信号,若对其每周期采样N点,则总运算量可降低到2nN次乘法和2n(N-1)次加法运算,信号的信噪比可提高（N／2）^-0．5倍。 相似文献
9.
A dynamic method suitable for shipboard measurement of the partial pressure of CO2 exerted by a seawater sample has been developed. The system consists of a paddle-wheel-type gas-water equilibrator and an infrared gas analyzer. Since the system is open to the atmosphere at the in-take and the exhaust ends, it can be operated stably on shipboard conditions. A precision of ±2% has been obtained for shipboard measurement of pCO2. 相似文献
10.
为了能够精确地测量海底表层沉积物的声学参数,自主研制了一种新型海底沉积物声学原位测量系统,与国内外传统的声学原位测量系统相比,该系统能够实时显示声波波形,调整测量参数,其工作方式除了站位式测量之外,还实现了拖行式连续测量,极大地提高了工作效率.根据前期海试情况,对海底仪器结构进行了重新设计,使之可以同时测量海底沉积物及海底海水的声学参数,同时建立了双向数字信道,解决了测量过程中系统信号的干扰问题.该系统的结构分为两部分:甲板控制单元和水下测量单元,整套系统通过主机控制程序进行控制,采用GPS定位系统测定仪器的大地坐标.为了检验系统的稳定性及准确性,分别进行了实验室水槽实验和海上试验.利用水声测量设备对测量系统进行实验室水槽标定分析,实验结果表明系统测量值相对误差仅为0.04%,测量结果具有较高的精度.海上试验在青岛胶州湾和东海海域进行,获得了试验区域海底沉积物声速和声衰减系数的测量数据,将测量数据与他人的研究结果进行对比分析,结果表明测量数据与前人研究结果一致,较为准确.该原位测量系统在站位式测量和拖行式测量中都能够快速准确地测量出沉积物声速和声衰减系数,可以作为海底底质声学测量的调查设备. 相似文献
11.
TOSHIO TANIGUCHI 《水文科学杂志》2013,58(1):22-32
SUMMARY One of the most important factors for the study of various problems of river-improvement and river-utilization is the measurement of amount of sand and gravels transported by water. However, to this date, no definite methods of the measurement have been discovered. The author found a new method of this measurement using a tiltmeter (with horizontal pendulum of Zöllner suspension). Applying this method, it is able to measure sediment load (bed load and suspended load) both at the time of low-water and flood. Also through this method, it is possible to observe and self-register variation of the rate of sediment transportation continuously in such a case as other methods are not useful. The test observation at Sukumo-gawa, Hakone-machi, Ashigara-gun, Kanagawa-pref, from September 1953 to November 1954 performed by the author of this articel was successful. Thus, this method has been put in practical use at upper stream of Katashina-gawa in Tone-river system, Gumma-pref, since July 1956. 相似文献
12.
David Walsh Peter Turner Elliot Grunewald Hong Zhang James J. Butler Jr. Ed Reboulet Steve Knobbe Tom Christy John W. Lane Jr. Carole D. Johnson Tim Munday Andrew Fitzpatrick 《Ground water》2013,51(6):914-926
A small‐diameter nuclear magnetic resonance (NMR) logging tool has been developed and field tested at various sites in the United States and Australia. A novel design approach has produced relatively inexpensive, small‐diameter probes that can be run in open or PVC‐cased boreholes as small as 2 inches in diameter. The complete system, including surface electronics and various downhole probes, has been successfully tested in small‐diameter monitoring wells in a range of hydrogeological settings. A variant of the probe that can be deployed by a direct‐push machine has also been developed and tested in the field. The new NMR logging tool provides reliable, direct, and high‐resolution information that is of importance for groundwater studies. Specifically, the technology provides direct measurement of total water content (total porosity in the saturated zone or moisture content in the unsaturated zone), and estimates of relative pore‐size distribution (bound vs. mobile water content) and hydraulic conductivity. The NMR measurements show good agreement with ancillary data from lithologic logs, geophysical logs, and hydrogeologic measurements, and provide valuable information for groundwater investigations. 相似文献
13.
用 SK 地震仪台网的资料,用联合确定地震震级、量规函数和台基校正值的方法,做出了中国大陆地区的均一震级系统,得到了 PZ、PH、SH、SV 四个震相从2.5——100新的量规函数,以及我国21个基准台的台基校正值.用这四个量规函数加上台基校正,求得的单台震级的标准误差为0.21——0.23级.6级左右的地震一般都有16个以上台记录到,这时求得的台网平均震级的误差可在0.05级左右.由于体波震级强烈地依赖于仪器类型,所以,我们求得的体波震级 msk与 mb 或 mB 有系统差.我们采取了使 msk与 Ms 接近的原则.提出了位移谱震级的概念:认为按某一震源参考球的平均值,具有相同强度的 P 波(或 S波)位移谱的地震,则震级相等.这种震级标度有以下优点:(1)它是绝对力学标度,可以把世界上各台网的震级统一起来;(2)物理意义明确,能反映地震大小.对任何大小地震都有定义,无饱和问题,对慢地震也有定义;(3)能和以前使用的震级衔接起来;(4)对位移计地震仪来说,测量方便,误差小. 相似文献
14.
The detectability of an intermediate layer in a three-layer earth model in the time domain has been investigated. The calculations were made for the perpendicular loop (designated system II) and vertical-coplanar (designated system III) electromagnetic (EM) sounding systems. The primary excitation employed is a train of half-sinusoidal and square waveforms of alternating polarity. The time-domain response has been determined by Fourier transformation of the matched complex mutual coupling ratios into the time domain and by linear digital filtering. Top and bottom layers have equal resistivity. EM responses have been computed for conductive and resistive intermediate layer with a wide range of thickness and for two values (500 m and 1000 m) of loop-separation. For the detectability analyses, the root mean square (rms) difference between three-layer and homogeneous-earth responses is adapted. The threshold value for detectability is defined as an rms difference of 10% and the measurement error is arbitrarily assumed to be of the order of 3%. It is observed that the perpendicular-loop system is better than the vertical-coplanar system in detecting thin intermediate layers (either conductive or resistive). For a loop separation of 1000 m and half-sinusoidal pulse excitation, the detectable thickness ratio (h2/h1) is 0.10 by system II for the conducting middle layers; for square pulse excitation the corresponding thickness ratios are 0.06 for system II and 0.12 for system III. For a loop separation of 1000 m and half-sinusoidal pulse excitation in detecting the resistive intermediate layers, the corresponding thickness ratios are 0.9 for system II and 2.25 for system III; while for square pulse excitation the thickness ratios are 0.55 for system II and 1.55 for system III. Results in the frequency domain and time domain (for half-sinusoidal and square pulsed field) have also been presented for systems II and III for detecting conducting layers by considering an earth model where p1≠ p3 and p3 > p1 (p is the resistivity). The loop separa- tion used is 1000 m. Direct comparisons between the frequency domain and time-domain results clearly demonstrate the superiority of frequency-domain systems for detecting con- ducting intermediate layers. 相似文献
15.
Yun-Lin Zhang Hai-Jing An Xiao-Ling Liu Yu-Lan Si Mei Jiang Wu-Si Zhang 《地震学报(英文版)》1993,6(3):675-683
The high accuracy, automatic, digital MT measurement system with five electromagnetic components was firstly adopted by the
author to the section MT monitor and measurement in the middle Qilian mountain in the Northwestern China, the more real precursory
information of impending earthquake electromagnetic rediation of GongheM=7.0 earthquake (April, 1990) in Qinghai province was obtained by the system.
The new complete quantification frequency analysis was firstly used in this paper in both time and space domains for the analysis
of repeated measurement data at all sites.
This paper concludes the precursory spectral characteristics of electromagnetic radiation before strong earthquake as following:
1. The spectra appears as the synchronous electric field interference type mainly of conduction current; 2. Narrow band (0.5
– 20s) of spectral period; 3. The singularity of amplitude (the pulse amplitudes of interference electric field is 102 times the normal values); 4. They show the directionality of preparing focus to some extent; 5. The intermittent of radiation
(three peak periods appeared three days before the main shock). It is more significant that there existed a relative quiet
period of about 48 hours between the peak period and the occurrence, observators can response quickly at observational sites
and take it as one of the observational criterions for impending prediction.
This paper also points out that the impending earthquake electromagnetic radiation obtained by the MT measurement system is
mainly the conduction current, and the high-conductive layer existed commonly in the crust may serve as the better paths for
the conduction current circuit and enables the far away MT measurement sites to receive it.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 186–193, 1993. 相似文献
16.
Complex resistivity and radar investigation of building material: First results of field scale measurements 总被引：1，自引：0，他引：1
Sabine Kruschwitz Ernst Niederleithinger Christiane Trela Jens Wöstmann 《Acta Geophysica》2010,58(1):96-113
Moisture ingress is one of major damaging factors for masonry buildings. As the complex resistivity (CR) is sensitive to textural
properties as well as to the pore fluid chemistry of wet porous media, its non-destructive application can provide helpful
information for conservators. In a comprehensive laboratory study it has been shown that CR might even be able to distinguish
between salt content and saturation degree in only one measurement. The combined use of electrical and electromagnetic measurement
techniques in two field-scale flooding experiments has shown some unexpected differences. Possible reasons are discussed and
it is shown that bringing together the information of both methods leads to a clearer picture. 相似文献
17.
18.
A three-dimensional seismometer array was installed in the Chiba Experiment Station of the Institute of Industrial Science, University of Tokyo in 1982. The array system consists of 44 three-component accelerometers densely placed both on the ground surface and in boreholes. A complementary system for the measurement of ground and buried pipe strains was also installed at the same site. The array system has been successfully in operation, and more than 160 earthquakes have been recorded. Considering a wide use of these seismograms, the Chiba array database has recently been created comprising twenty-seven major events. This paper describes the Chiba array system and its strong motion database. Results of engineering analysis using the selected records are also presented. 相似文献
19.
无机阴离子及溶解性有机质对程海化学需氧量测定值的影响 总被引：1，自引：0，他引：1
自2005年以来,程海水体的化学需氧量(COD)持续升高,而生化需氧量(BOD)却维持不变,高锰酸盐指数(COD_(Mn))升高也较缓慢.为研究程海COD持续升高的原因,选取程海水体中具有代表性的无机阴离子(Cl~-、F~-、S~(2-)、HCO_3~-)和溶解性有机质(DOM)中不同浓度的胡敏酸(HA)、富里酸(FA)和商品化腐殖酸(SHA),研究其对COD和COD_(Mn)测定的影响,探讨Cl~-和DOM共同存在下对COD测定的影响.结果表明:程海水体中Cl~-浓度对COD存在显著影响,产生的COD值为5.42 mg/L,S~(2-)、F~-和HCO_3~-对COD影响较小;各离子对COD_(Mn)的影响很小;不同浓度梯度的HA、FA和SHA与COD测定结果呈显著线性相关,氧化1 mg C HA、FA和SHA所产生的COD值分别为2.164、1.964和2.362 mg;氧化1 mg C HA和FA所产生的COD_(Mn)值分别为0.646和0.344 mg;DOM对COD测定值的影响显著大于对COD_(Mn)测定值的影响;且一定浓度Cl~-的存在增强了FA与HA对COD测定的影响.该研究为进一步阐明程海COD逐步升高,COD_(Mn)值缓慢升高的内在原因奠定了基础. 相似文献
20.
Multiphase suspension systems are used extensively in hydrology, biochemistry, and the food industry. Ultrasonic spectroscopy is a rapid, on‐line, non‐invasive measurement technique for suspension characterization over different particle sizes and a wide range of concentration. Although the properties of kaolin suspensions have been investigated extensively, kaolin ultrasonic attenuation properties at different temperatures and concentrations have not yet been reported. Through experimental validation in the laboratory, this study provides results from a series of measurements of kaolin ultrasonic attenuation over a wide range of concentrations (0–300 000 ppm) and practical temperatures (5–25 °C). The ultrasonic measurement of attenuation of sediment sampled from the Shihmen reservoir in Taiwan is also investigated. Results show that variations in ultrasonic attenuation are driven by concentration and temperature. Two regression functions are established to quantitatively relate attenuation to kaolin concentration and the Shihmen reservoir sample at a given temperature. An ultrasonic system is designed and manufactured for real‐time sediment concentration monitoring in the Shihmen reservoir based on these experimental ultrasonic attenuation measurements. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献