The digital seismometer, a modern instrument     

N. V. Trifonov 《Seismic Instruments》2009,45(1):83-85

On the basis of an analysis of the development history of seismometers, the conclusion is made that a new generation of instruments—digital seismometers—should be created. The functions of a digital seismometer and its advantages over other existing instruments are described in brief.  相似文献   

H_∞ drift control of time-delayed seismic structures   总被引：1，自引：1，他引：0  

Chang-Ching Chang 《地震工程与工程振动(英文版)》2009,8(4):617-626

In this paper,an optimal H∞ control algorithm was applied to the design of an active tendon system installed at the first story of a multi-story building to reduce its interstory drift due to earthquake excitations.To achieve optimal control performance and to guarantee the stability of the control system,an optimum strategy to select control parameters γ and α was developed.Analytical expressions of the upper and the lower bounds of γ and α were obtained for a single degree-of-freedom system with state fee...  相似文献   

滑坡动态综合治理各阶段的监测信息反馈     

尹光志  张卫中  康钦容 《岩土力学》2006,27(Z1):661-664

滑坡监测是滑坡综合治理中一项必不可少的环节,不同阶段发挥着重要的作用。借助监测,能了解滑坡的实际状况,可以判断其稳定性及所处变形阶段,为滑坡治理初步决策提供科学依据。在治理过程中,实时监测反馈又为设计方案的修改和补充以及现场信息化施工提供可靠资料,为工程质量提供保障,施工结束后的监测数据又视为工程治理效果的直接指示 器。以某古滑坡路段高边坡综合治理中各阶段的监测为例,介绍了不同阶段的监测方法以及所获得的数据信息在滑坡治理中的作用。  相似文献   

结构振动控制的两个理论问题   总被引：1，自引：0，他引：1  

张俊平  禹奇才  周福霖 《地震工程与工程振动》2000,20(1):125-129

针对结构振动控制的两个理论问题,提出了自己的见解,阐明了这些理论问题对应用研究及工程实践的指导意义。  相似文献   

城市化影响地下水水质的正负效应   总被引：3，自引：0，他引：3  

于开宁万力  都沁军 《地球科学》2003,28(3):333-336

以石家庄市为例, 通过城市化水平和地下水污染态势的定量计算、分析, 对城市化影响地下水水质的机理及其正负效应进行了探讨.结果表明: 石家庄城市化发展处于初级阶段; 城市化影响地下水水质有正负两方面的效应, 城市化水平的提高, 有助于改善地下水水质, 但却易于加剧地下水盐污染.本研究为以地下水作为主要、甚至唯一供水水源城市的可持续发展提供了一种理论和根本途径.   相似文献   

北半球环流季节演变机制   总被引：4，自引：2，他引：2  

蔡尔诚 《气象与环境科学》2000,(3):8-9

提出了北半球大气环流季节变化的一种反馈机制：外界（太阳、海洋、陆地等）的热力强迫加热大气,形成波状低云;而波状低云又使高中纬大气冷却,进而影响高纬冷气团冬夏变化。根据波状低云影响高纬冷气团变化这一负反馈过程,对1958－1993年进行夏季旱涝预报试验,结果每年中国东部的主雨带基本可正确预测出来。  相似文献   

一种实用的铂热电阻温度巡检仪     

龚一光  杨家仕 《成都信息工程学院学报》2000,15(2):131-135

介绍了一种经济实用的 16通道铂热电阻测温巡检显示仪 ,并论述了铂热电阻的引线消除和用正反馈实现非线性校正的方法。  相似文献   

迭代逼近科学方法在速度估算中的作用     

陈宝孚  李貅 《地球科学与环境学报》2000,22(2):67-70

以地球物理中的速度为题 ,在详细描述了速度参数重要作用、各类速度基本概念及其应用范围、影响速度估算的各种因素的基础上 ,以模型和处理流程的叠加速度分析为例 ,在两个层面上展现了迭代逼近方法。又以剩余层速度分析为例 ,说明了具有反馈控制思想的迭代逼近算法 ,从而指出该方法在速度估算中的重要作用  相似文献   

Catchment chemostasis revisited: Water quality responds differently to variations in weather and climate     

Sarah E. Godsey  Jens Hartmann  James W. Kirchner 《水文研究》2019,33(24):3056-3069

Solute concentrations in streamflow typically vary systematically with stream discharge, and the resulting concentration–discharge relationships are important signatures of catchment biogeochemical processes. Solutes derived from mineral weathering often exhibit decreasing concentrations with increasing flows, suggesting dilution of a kinetically limited weathering flux by a variable flux of water. However, previous work showed that concentration–discharge relationships of weathering‐derived solutes in 59 headwater catchments were much weaker than this simple dilution model would predict. Instead, catchments behaved as chemostats, with rates of solute production and/or mobilization that were nearly proportional to water fluxes, on both event and interannual timescales. Here, we re‐examine these findings using data for a wider range of solutes from 2,186 catchments, ranging from ~10 to >1,000,000 km² in drainage area and spanning a wide range of lithologic and climatic settings. Concentration–discharge relationships among this much larger set of larger catchments are broadly consistent with the previously described chemostatic behaviour, at least on event and interannual timescales for weathering‐derived solutes. Among these same catchments, however, site‐to‐site variations in mean concentrations of weathering‐derived solutes exhibit strong negative correlations with long‐term average precipitation and discharge, reflecting strong climatic control on long‐term leaching of the critical zone. We use multiple regression of site characteristics including discharge to identify potential controls on long‐term mean concentrations and find that lithologic and land cover controls are significant predictors for many analytes. The picture that emerges is one in which, on event and interannual timescales, weathering‐derived stream solute concentrations are chemostatically buffered by groundwater storage and fast chemical reactions, but each catchment's chemostatic “set point” reflects site‐to‐site differences in climatically driven evolution of the critical zone. In contrast to these weathering products, some nutrients and particulates are often near‐chemostatic across all timescales, and their long‐term mean concentrations correlate more strongly with land use than climatic characteristics.  相似文献   

Single/multiple input-single output transfer function with noise models for constituents of iron ores of Northern Goa, India     

P. S. Raiker  B. K. Sahu 《Mathematical Geology》1985,17(7):755-767

Parametric time domain time series models for different chemical constituents such as SiO ₂,Fe ₂ O ₃,TiO ₂,MnO, and P ₂ O ₅ of iron ores belonging to banded hematite quartzites in Bicholim Mine (Goa) have been utilized for forecasting Fe ₂ O ₃ assay values through single/multiple input—single output (Fe ₂ O ₃ ) transfer function with noise methodology. Statistically significant correlated chemical constituent inputs (say, SiO ₂,TiO ₂,MnO, P ₂ O ₅ ) along lateral (horizontal strike direction) and vertical (perpendicular to bedding planes) sections in this mine are useful in modeling as well as forecasting assay values of blocks of ore to be exploited. Parameters of transfer function—noise models are estimated by utilizing time domain methodology, and the usefulness of these models for optimization of mining operations is discussed.  相似文献