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地电阻率仪器在工作中容易出现无电流、电流不稳等故障现象,不易排查维修.通过对仪器工作原理和供电回路过程进行研究,发现供电回路中间仪器的内部或外部各接头接触不良是造成上述现象的主要因素.根据存在的问题,洛阳地震台研制出供电回路故障检测板.该检测板可利用其继电器上LED灯的工作状态和动作时序,快速查找、排除相关供电回路故障... 相似文献
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本通过对发生在云南省的澜沧－耿马等几次地震记录的分析，提出了适合云南实际的地震动反应谱特性Ｖｍａｘ／αｍａｘ值的ｗｅｉｂｕｌｌ模型，并求出了平均值和标准差，对于样本不足的给出了ｍ，η的置信区间，可为我国、特别是云南省的工程建设提供基础依据。 相似文献
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目前768遥测系统使用的半导体稳压电源,起着供给接收机与发射机电源的作用。因其为70年代中期产品,常年连续工作,且采用分立元器件组装电路,所以故障较多。如大功率调整管(3DD102B)取样放大管与推动管易击穿或烧断,很多情况下是3只晶体管同时击穿,该机的可靠性与负载稳定度较差,这样给维修、特别是子台维修带来不便。从临汾遥测台网各子台几年来的故障来看,约占全部故障的30％～40％,由于故障多,维修频繁,不仅造成人员车辆器材的消耗增大,而且断记率高。直接影响台网监测能力的发挥。 针对以上情况,我们对768稳压电源做了以下两 相似文献
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Ｄ／ｍａｘ－Ａ型Ｘ射线衍射仪升级改造项目采用工业控制机原理，设计了与ＩＢＭ兼容计算机相配的通用接口和相应的软件，实现了在日本理学Ｄ／ｍａｘ－Ａ型Ｘ射线衍射仪上用ＩＢＭ－ＰＣ机取代原单片机和操作台的升级改造。由此建立的ＪＡ型Ｘ射线衍射仪微机控制系统对测角仪转角控制精密、准确、可靠，数据采集实时、准确。它不仅保留了原系统的所有功能，保持了仪器原有的精度和分辨率，而且还增加了自动光路零位校正功能，由于采 相似文献
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针对宿迁台FHD型质子矢量磁力仪观测数据从2020年4月28日出现噪声增大问题,我们通过对仪器参数设置、观测环境、观测仪器、运行状况分类逐一进行检查、排查与分析,确认FHD仪器主机发生故障。故障原因为仪器补偿电流电路中的电容器件老化被击穿,检修更换器件得以解决。经检修后,该仪器观测数据磁偏角D、水平分量H和垂直分量Z的计算平均噪声由故障时的1.19′、1.45 nT、1.58 nT降低为0.82′、0.32 nT、0.50 nT,各分量噪声水平获得了明显的改善。通过对地磁仪器和外部观测环境问题的分类检查、检测与判断,并对查明引起数据噪声增大原因归类总结,为地磁台站查找分析数据噪声变大主要原因提供一种科学有效的检测方法。 相似文献
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土的动模量和阻尼比的经验估计 总被引：56，自引：8，他引：56
本文对现有土的动应力－应变关系试验成果进行了分析和总结，推荐了用不同物性指标估算Ｇｍａｘ的经验公式，用塑性指数Ｉｐ描述Ｇ／Ｇｍａｘ－γ和λ－γ关系的经验曲线，并提出了用Ｉｐ为参数的Ｇｍａｘ、Ｇ／Ｇｍａｘ－γ和λ－γ曲线的经验公式，对工程应用颇有实用价值。 相似文献
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研究的问题是地震危险性参数的统计估计，重点是最大区域震级Ｍｍａｘ及未来时间间隔Ｔ内最大震级Ｍｍａｘ的估计及其分布的参量分位数，提出了两种估计：最小方差的无偏估计和贝叶期估计。作为一种实例，已将上述方法应用于加利福尼亚和意大利的Ｍｍａｘ及相关参数的估计。 相似文献
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大连地磁台三分量地磁仪原配用 CB-3型磁变仪配电盘用以提供记录灯电流 ,标定电流及三分量转换开关 ,随着磁照图质量越来越高 ,对标定电流的稳定性 ,电流的升降特性要求也越来越苛刻 ,原 CB-3型磁变仪配电盘很难适应 ,鉴于地磁全面化改造还有待时日 ,即使改造后可能仍需平行观测一个时期 ,应地震台的要求设计制作了这种三分量地磁仪自动标定电源。1 主要性能指标提供可调记录灯电流 80～ 1 3 0 m A;记录灯断丝报警 ;自动时号 ,曝光量连续可调 ,时号指示 ;定时触发标定 ;三分量标定过程自动完成 ;标定节拍连续可调 ;标定电流升降斜率由节… 相似文献
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张延武 《CT理论与应用研究》1994,3(2):40-41
ＣＴ机在正常扫描情况下，图象上出现了一簇斜方向伪影。同时屏显ＵＳ００８０错误信息。从提示的错误信息分析，会有许多原因导致ＵＳ００８０信息出现．本文讨论了由于ＧＣＰ信号瞬间丢失而产生的图象伪影。以及修复过程同时也找出了，由于ＢＳＰ内５Ｖ电源低于正常值而产生的图象上有点状伪影的故障原因。 相似文献
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Behnam Haidari Alireza Riyahi Bakhtiari Vhid Yavari Ali Kazemi Golshan Shirneshan 《洁净——土壤、空气、水》2013,41(2):166-173
Vanadium and nickel are two important indicators of oil pollution. Lengthy exposure to these elements causes serious harmful effects in human health, different harsh allergies being examples. The accumulation of two heavy metals (Ni and V) in sediment and the soft and hard tissues of Saccostrea cucullata were analyzed at three sampling sites along the coast of Lengeh Port, Persian Gulf. Results indicated at all the sampling sites; the Ni levels in soft tissues (STs) were higher than in the shells (SHs) and sediments, whereas the V levels were higher in the sediments. In addition, meaningful relationship (r = 0.65; p < 0.05) was observed across Ni levels in ST of S. cucullata and sediment, while for V concentrations a strong relationship (r = 0.83; p < 0.01) was found in SH of S. cucullata and sediment. This indicates that ST and SH of oyster can be considered as a biomonitoring agent for Ni and V levels, in coastal waters, respectively. The exposure of the consumer is compared directly to minimal risk level and provisional maximum tolerable daily intake. Result indicated that levels of Ni and V were within the safety limits for human consumption. 相似文献
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以钟祥马岭井历年水温观测资料为研究对象,发现2套SZW-1A型数字水温仪记录的数据曲线自2016年7月以来均具有“V”型异常特征,从观测系统、地震、降雨等因素进行分析,排查干扰因素,并分析水温变化的可能机理,认为现该异常应为降雨干扰所致。干扰机理如下：降雨量累积值达40 mm以上,降雨迅速补充地下水,浅层冷水经井段223—246 m处存在的岩石裂隙、断层、溶洞等渗入井孔,造成静水位迅速上升,井水温度随之下降,上下层冷—热水之间的热传导使得位于井孔深部的水温下降;降雨结束,地表水渗入量减少,水温逐渐恢复正常。 相似文献
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Richard P. Mühleisen 《Pure and Applied Geophysics》1971,84(1):112-115
Summary The electrode effect could be detected in full magnitude on the Atlantic during the expedition of the research vessel Meteor. The average value of the electric field over the sea surface is about 125 V/m, in about 10 to 100 m over the surface only about 60 V/m. This phenomenon as well as the results of small ion records lead to a value of the air earth current density on the sea of only 0.9×10–12 A/m2, a quarter of the value accepted up to now. With these values the total current of the global air electric circuit will be about 665 A instead of 1500 to 1800 A. The ionosphere potentials over two places in a distance of 8000 km at 15 dates are nearly identical and in the average 280 kV. 相似文献
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The spontaneous and evoked activity of electroreceptors were electrophysiologically studied. The results are:
- The spontaneous discharge rate ranged from 15 to 85 imp/s with a mode of 50 imp/s for 126 organs of 18 animals.
- By analysis of periodic histograms and interspike interval histograms of responses to sinusoidal electric stimulations, the frequency response characteristic was determined. The frequency response curve shows a band pass type, the band width ranged from 5 Hz to 30 Hz and the best frequency is around 15 Hz.
- The thresholds of responses for 47 organs were measured by injection of sinusoidal current into the organs. The threshold values were less than 0.1nA (61µV/cm) for 35 organs (74%), and less than 0.01nA (6.1 µV/cm) for the rest of 9 organs (19%).
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Dietrich Borchardt Bernhard Statzner 《Aquatic Sciences - Research Across Boundaries》1990,52(4):299-314
Urban stormwater runoff discharged through sewer systems into streams causes flush spills of water and pollutants in the receiving water. To make the right decisions in future plannings of the very costly rehabilitation of sewer systems, a solid ecological data base on the critical parameters of sewer overflows is badly needed. Therefore, we designed a laboratory flume which was operated in circular flow mode (to ensure adaptation of the test organisms) and in flow-through mode during the simulation of sewer overflows (to allow a proper evaluation of population loss by drift). Examples on the behaviour during the adaptation phase and the population loss during the exposure to flush spills of water and/or a mixture of sewage and clean water of a benthic invertebrate (Gammarus pulex) demonstrate the potential of the flume to identify critical parameters of sewer overflows at quasireal-world-conditions. We found clear evidence for synergetic effects since the exposure to high flow and sewage caused higher population loss ofGammarus than the sum of population loss at exposure to only high flow or only sewage. Population loss considerably depended on the availability of refugial space: if the interstices of the gravel in the flume were silted, this loss was higher than at open interstices. Only ten minutes of movement of the material forming the flume bottom reduced the population ofGammarus to about 60 or 50% of its initial size. Hence, our data strongly suggest that the characteristics of the receiving stream (refugial space, bed stability) play an important role for the potential ecological impact of a sewer overflow. Changes of stream morphology and/or creation of refugial space plus an appropriate technical solution for overflow treatment may be less costly and more effective than a large-scale technical project. Thus, the stream itself should be a major element in future management decisions. 相似文献
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Janet Barco Terri S. Hogue Victoria Curto Laura Rademacher 《Journal of Hydrology》2008,360(1-4):31-47
Urbanization represents a dramatic example of human interference with the hydrological cycle. Changes to ground cover affect both the hydrological and geochemical characteristics in a watershed. Ecosystem degradation also occurs in undisturbed watersheds at the “urban fringe” due to regional atmospheric deposition. These urban fringe catchments can also serve as an upstream source of various chemical constituents into downstream (urban) river systems. The current study focuses on the impacts of regional urbanization in the upper Arroyo Seco watershed located on the eastern edge of the Los Angeles basin, where estimates of dry deposition are considered some of the highest in North America. Collected hydrologic, geochemical and atmospheric data were assessed at seasonal time scales to evaluate current hydrochemical dynamics. Stream water chemical composition in the upper Arroyo Seco watershed exhibits significant seasonal variability, particularly for . Almost all study solutes show dilution behavior. However, hydrologically enhanced behavior was observed for with increased concentrations during the wet season. Seasonal stream concentration–discharge relationships were developed using a hyperbolic dilution model. The developed model was then used to predict concentrations for observational gaps in stream water chemical composition, allowing for seasonal and annual mass loadings to be estimated for the downstream urban stream. The hydrological signal in the resultant chemical loads is extremely strong, especially during the wet season. Both observations and model predictions indicate the watershed is a sink for atmospheric nitrate and a source for various cations. 相似文献
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Federico Von Giovanoli André Lambert 《Aquatic Sciences - Research Across Boundaries》1985,47(2):159-178
Results obtained by means of an ultrasonic current meter in the plume of the Rhone river are summarized as follows:
- Currents of Rhone river water entering the lake were clearly discernible up to a distance of about 1 km from the river mouth. The interflow was observed at depth of 10 to 30 m.
- Interflow velocities decreased with increasing distance from the river mouth: from 40cm/s at a distance of 350 m to about 15 cm/s at 1 km.
- Short-term variations of current velocities and directions documented the highly turbulent nature of the interflow.
- The entering river water (inflow direction to the NNW) interfered with a persisting northeastward current of the lake water. At a distance of 1–2 km from the mouth the interflow gradually assumed the same direction, possibly due to deflection by Coriolis forces.
- Current velocities showed considerable variations within a time scale in the order of hours at the same measuring position. The reasons for these fluctuations remain unclear. Possible causes may be lateral oscillations of the entering river water or its deviation by river mouth bars during periods of reduced river discharge. Variations of the discharge alone cannot explain these current fluctuations.
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Surface-to-base amplification evaluated from KiK-net vertical array strong motion records 总被引：2，自引：0，他引：2
Site amplification defined as the peak value of spectrum ratio was investigated using surface and base accelerations recorded in a number of KiK-net down-hole arrays in Japan during three major earthquakes. An important task was to determine the spectral amplifications relative to outcropping motions with the aid of the down-hole array records. Based on soil data available for individual arrays, theoretical amplifications were calculated and adjusted to coincide with the peak amplifications of the array records. A good and unique correlation was found between the peak amplifications thus obtained and S-wave velocity ratios, defined by S-wave velocity in base layer divided by average S-wave velocity , for different sites and different earthquakes. The value of was evaluated from fundamental mode frequency and the thickness of an equivalent surface layer in which peak amplification is exerted. The conventional parameter Vs30; averaged shear wave velocity in the top 30 m used in current design codes, did not correlate well with the obtained amplifications. It is suggested that may be determined not only from Vs-logging data but also from microtremor measurements. 相似文献
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10.6～1.5GPa、室温～1 200℃条件下青藏高原地壳岩石弹性波速特征 总被引：3，自引：2，他引：3
通过对采自青藏高原的六种地壳岩石，包括花岗闪长岩、混合岩、片麻岩、玄武岩、辉橄岩及斜长角闪岩等，进行高温高压纵波速度测量，发现绝大多数地壳岩石其纵波速度在压力高于0.2-0.3GPa时基本上随压力线性增加。在固定压力下随温度升高而降低，但在温度较低时这一现象并不明显，随温度的程式高波速出现明显降低。通过对实验后的样品进行显微薄片分析，发现含水矿物的脱水和部分熔融是造成岩石波迅速降低的主要原因。在实验过程中还发现高压下温度较高时，接收到的超声波振幅会增大。对实验中发现的这些现象本文进行了初步的分析和讨论。 相似文献