地下厂房洞室群岩爆趋势综合预测方法

以拉西瓦水电站地下厂房洞室群原设计方案为例，基于其赋存地质条件调研结果和岩爆产生基本条件，对岩爆趋势进行宏观预测；并结合研究区其他高地应力现象，建立了岩爆预测类比判据。进而基于厂房开挖后二次应力场数值计算结果，以所建判据圈定了岩爆可能发生部位及强烈程度。结果表明，将宏观判据与类比判据结合的岩爆综合预测方法，考虑因素全面，也尊重了研究区实际情况，因而合理可行。     

PC－1500机配合坐标仪的地形数据采集程序

本文描述ＰＣ－１５００计算机与ＨＣＺ－１立体坐标量测仪相配合的地形点数据采集程序，并对该程序的结构、有关的数据模型以及使用等作了说明。     

山西数字与模拟地震台网的资料对比研究

山西数字遥测地震台网于2000年10月1日投入考核运行，为使数字遥测地震台网与模拟地震台网测定的时、空、强地震参数顺利接轨，尽快发挥数字资料在日常工作中的效益，将山西数字遥测地震台网产出的资料与模拟地震台网产出的资料作了全面细致的对比分析，研究了它们之间的相关程度、一致性、差异性。结果表明，数字地震观测系统比模拟地震观测系统具有更高的拴震率，得出山西数字遥测地震台网产出的资料与模拟地震台网产出资料相关性较好、定位结果在误差范围之内、符合《数字地震及前兆观测技术规范》要求的结论。     

Granular experiments of thrust wedges: Insights relevant to methane hydrate exploration at the Nankai accretionary prism

The accumulation mechanism of methane hydrates has been a central issue in previous hydrate research regarding the Nankai accretionary prism, southwest of Japan. Expulsion of formation fluids is significant during the prism accretion process, and the migration of these methane-bearing fluids exerts a strong control on the accumulation of hydrates. Two types of fluid pathways, inter-granular porosity and faults, need to be evaluated to understand hydrate accumulation. Fluid migration along faults can be partly modeled by examining faulting activity. Our study modeled the accretion process by using two granular methods that approximated the geologic body as an assemblage of particles: (1) analog experiments using granular materials, and (2) a numerical simulation based on the distinct element method. The analog experiments closely reproduced the prism geometry observed in seismic profiles across the Nankai accretionary prism. Digital image correlation analysis indicated that the frontal thrust is generally active but older structures are also frequently reactivated. The numerical simulations produced prism geometries similar to those of the analog experiments. The velocity distributions of the particles showed evidence of episodic faulting and reactivation, but the internal stress field exhibited little change in the deeper part of the prism during deformation. The frequent and substantial changes in fault activity displayed by the models indicate episodic fluid flow along fault surfaces. Active frontal thrusting suggests that formation fluids generally migrate from deep within the prism to the deformation front, but may move along reactivated older faults. Inter-granular permeability also fluctuates, as it is controlled by temporal and spatial variations in the internal stress field. However, fluid flow is likely to be relatively stable in the deeper segment of the prism.     

WILD PPO-8制作正射影象图的实时控制

本文从倾斜象片与水平象片的透视关系出发,考虑A_8精密立体测图仪的转角系关,导出了模拟计算机比例尺缩放和影象旋转改正公式和实际运算公式,进而阐述了PPO-8正射投影装置是如何实现对ZOOM系统和DOVE系统两个基本公式的控制。     

Effects of Volcanic Ash on Computers and Electronic Equipment

Computers and electronic equipment are an important component of the infrastructure of our modern environment. It is therefore essential that we know the effects of volcanic ash on such equipment. This paper presents the results of a pilot study to test computers and cooling fans in an ash-charged environment to assess their vulnerability. In the experiment, ash was poured on to computers and cooling fans in a sealed 0.216 m³ perspex box, with the effects on both the ash and the equipment monitored. Three different types of ash (1996 Ruapehu andesitic ash, Sakurajima andesitic ash and Kaharoa rhyolitic ash) were used in the experiments.In the first experiment each type of ash was photographed by Scanning Electron Microscope (SEM), then passed through the bearing unit of a cooling fan and photographed again afterwards. The bearings within the cooling fan continued to work even after 720 h of testing and there was no significant abrasion of the fan-shaft bearing. The ash was however fragmented, suggesting that the brittle ash shattered to fine dust, which caused significantly less abrasion to the bearings or shaft than expected. Three computers were then tested in the sealed box. Ash was introduced at increasing rates to simulate catastrophic entry of ash into a work environment, and computers were tested throughout using the BURNIN^® testing programme. Failure times ranged from 100 to 150 h; most failures occurring when humidity was increased by spraying water mist into the airflow. If dried out the computers continued to operate again if failure was not catastrophic. Card slot edge connectors proved to be one of the weakest links, as a bridge of ash formed across the gap. They were also subject to abrasion with some of the gold plating being removed. This did not however cause operating difficulties.The conclusions are that computers are more resilient than originally thought, unless the ash is moist. Simple low-tech procedures should be adequate to protect computers from small amounts of dry and moist ash contamination.     

水工地下大洞径断面开挖轮廓线监理检测

隧洞断面开挖放样是直接为施工服务的,而检测工作是监理人员必须的工作。监理人员结合测量仪器和计算工具,依据具体的施工图纸进行隧洞断面开挖检测验收,检查开挖断面尺寸,核定超挖部分回填混凝土量。本文就海原县石峡口水库水工建筑物地下大洞径隧洞断面开挖后的检测计算方法作了论述,找出了解决该问题的办法,希望为类似工程监理及施工工作起到抛砖引玉的作用。     

Magnetic Field Feedback Circuit for Geomagnetic Field Compensation Control

In the current state of geomagnetic instrument testing, some aspects of geomagnetic instrument performance are difficult to test in the laboratory. If laboratory test results are inadequate, the instrument will have multiple problems while operating in the field, where a geomagnetic instrumentation test platform with a stable natural magnetic field is critical. Here, the magnetic field feedback circuit for geomagnetic field compensation control is studied in detail. That is, the magnetic field measured by the feedback magnetic sensor and the required working magnetic field are compared as input to the system, and the electric signal is transmitted to the feedback coil through an analog circuit to form a closed loop control, which provides compensation to control the magnetic field. Compared with the existing magnetic shielding method, the analog control circuit can achieve the realization of any working magnetic field, and it is not limited to a null magnetic field. The experimental result shows that the system compensates the earth''s magnetic field of 10,000nT with an average error of 10.6nT and average compensation error of 0.106%, providing a high compensation accuracy. The system also shows high sensitivity and excellent stability. The feedback circuit has achieved effective compensation control for the earth''s magnetic field.     

基于数字音频接口的地震数据采集电路板快速评估方法*

在宽频带数字地震观测技术领域,提出一种基于数字音频接口(S/PDIF接口)的数据采集电路板快速评估方法。该方法在数据采集电路设计过程中,在模拟/数字转换电路的输出端增加了一组S/PDIF数字音频接口,将模/数转换结果转换为符合音频传输标准的编码数据,并将此数据利用外置声卡同步传输到计算机,在计算机上进行数字抽取滤波、频谱分析等数据处理与解析,从而实现对地震数据采集电路板的快速评估。实验结果表明,该方法思路清晰,实现简便,结果有效可靠,能够解决常规测试评估方法中存在的问题,在高精度、高采样率数据采集技术研发和测试评估方面,具有比较强的实用性和应用前景。     

Building Environmental Literacy through Participation in GIS and Multimedia Assisted Field Research

Abstract

A Learning Support System (LSS) that emphasizes experiential research in natural environments using the cutting-edge technologies of GIS and multimedia has been developed for teaching environmental literacy to undergraduate students at the University of Georgia. Computers are used as cognitive tools to create a context in which students become interns in an ecological research center. Students are instructed to conduct research in the form of two field laboratories (the stream and forest laboratories). They accomplish their tasks by collecting data in the field (the State Botanical Garden of Georgia near the campus). They enter the data in the Learning Support System (LSS), and are guided to formulate hypotheses relating to stream water quality and human impact on forest succession for testing. Students also interact with the Environmental Research Support Site (ERSS) within the LSS for explanations to their findings. A specially customized Arc View GIS program within the LSS provides a tool to students for spatial analysis in the case of the forest laboratory. Students and faculty evaluations as well as final examination results confirmed the receptiveness of students to the LSS approach and its effectiveness in the learning of environmental literacy.