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61.
62.
伸展地区铲式正断层作用及其大地测量观测 总被引:1,自引:1,他引:1
铲式正断层作用是伸展构造区最主要的构造运动形式。本文根据铲式正断层作用的几何学、运动学特征,结合华北平原伸展区大地测量观测成果,探讨伸展区构造形变铲式正断层现今活动的地表形变效应及其动态特征。 相似文献
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64.
With the Taihu Basin as a study area, using the spatially distributed and mechanism-based SWAT model, preliminary simulations of nutrient transport in the Taihu Basin during the period of 1995:_2002 has been carried out. The topography, soil, meteorology and land use with industrial point pollution discharge, the loss of agricultural fertilizers, urban sewerage, and livestock drainages were all considered in the boundary conditions of the simulations. The model was calibrated and validated against water quality monitoring data from 2001 to 2002. The results show that the annual total productions of nitrogen (TN) and phosphorus (TP) into Lake Taihu are 40000t and 2000t respectively. Nutrient from the Huxi Region is a major resource for Lake Taihu. The non-point source (surface source) pollution is the main form of catchment sources of nutrients into Lake Taihu, occupied TN 53% and TP 56% respectively. TN and TP nutrients from industrial point pollution discharge are 30% and 16%, and sewerage in both forms of point source and non-point source are TN 31% and TP 47%. Both the loss of agricultural fertilizers and livestock drainages from the catchment should be paid more attention as an important nutrient source. The results also show that SWAT is an effective model for the simulation of temporally and spatially nutrient changes and for the assessment of the trends in a catchment scale. 相似文献
65.
In this paper, a number of robust biased estimators (e.g. ordinary robust ridge estimator, robust principal components estimator,
robust combined principal components estimator, robust single-parametric principal components estimator, robust root-root
estimator) are established by means of a unified expression of biased estimators and based on the principle of equivalent
weight. The most attractive advantage of these new estimators is that they can not only overcome the ill-conditioning of the
normal equation but also have the ability to resist outliers. A numerical example is used to illustrate that these new estimators
are much better than the least-squares estimator and various biased estimators even when both ill-conditioning and outliers
exist.
Received: 14 November 1995/Accepted: 11 February 1998 相似文献
66.
秩亏自由网平差的一种新解法 总被引:2,自引:1,他引:1
提出秩亏自由网平差的一种新解法,只亲知道误差方程系数阵中t0个线性无关的列向量,就能很快地得到最小二乘最小范数解,实际计算表明,这种新解法是简单有效的。 相似文献
67.
Gui Liu Yongsheng Zhou Changrong He Wenming Yao Junlai Liu Yuanyuan Zhang 《Geological Journal》2016,51(1):92-112
We performed deformation experiments on a foliated mylonite under high temperature and pressure conditions in this study. To investigate the effect of pre‐existing fabric on the rheology of rocks, our samples were drilled from natural mylonite with the cylinder axis parallel to the foliation (PAR) and perpendicular to the foliation (PER). We performed 25 tests on seven PAR samples and 21 tests on seven PER samples at temperatures ranging from 600 to 890 °C, confining pressures ranging from 800 to 1400 MPa, and steady‐state strain rates of 1 × 10−4, 1 × 10−5 and 2.5 × 10−6 s−1. In the temperatures of 600–700 °C, the deformation is accommodated by semi‐brittle flow, with the average stress exponent being 6–7 assuming power law flow; in the temperature range of 800–890 °C, deformation is mainly by plastic flow, with an average stress exponent of n = 3 and activation energies of Q = 354 ± 52 kJ/mol (PER and PAR samples). The experimental results show that the strengths of PER samples are higher than those of PAR samples. Deformation microstructures have been studied by optical and electron microscopy. The original foliation of PER samples is destroyed by deformation and replaced by a new foliation, but the deformation of PAR samples followed the original foliation. Electron backscatter diffraction (EBSD) measurements show a strong lattice preferred orientation (LPO) of the quartz c axis fabrics of the starting samples and deformed PER and PAR samples. However, the c axis fabric of quartz in experimentally deformed PER and PAR samples varied with temperature and strain rate is different from that seen in the starting mylonite sample. The initial quartz c axis fabric of the starting mylonite sample has been transformed into a new fabric during experimental deformation. Dehydration melting of biotite and hornblende occurred in both PER and PAR samples at temperatures of 800–890 °C. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Extracting the contiguous coal seams under the lowermost aquifer in the unconsolidated Cenozoic alluvium is apt to water and quicksand inrush. By using a series of investigation methods including empirical formulas, numerical simulation, theoretical analysis, etc., the study focused on the fracture and the excess pore water pressure in the overlying strata in the process of extracting no. 8 coal seam firstly and no. 9 coal seam (under no. 8 coal seam) subsequently in no. 8102 working face of Luling coal mine in the north of Anhui Province of China. When no. 8 coal seam was extracted, the water-conducting fractured zone penetrated into the lowermost aquifer and rapid dissipation of excess pore water pressure above the gob occurred, accompanied by relatively high seepage hydraulic gradient over the headgate and the tailgate. When no. 9 coal seam was extracted, failure did not obviously extend upwards and the excess pore water pressure decreased slowly and a relatively high seepage hydraulic gradient transferred downwards from the headgate to the tailgate in the inclined profile. The safe water head (H s) in the lowermost aquifer was confirmed to 15.6 m. Therefore, water and quicksand inrush was avoided effectively in the process of extracting the contiguous coal seams by dewatering, controlling mining height, and laying double resistance nets in the working face. 相似文献
70.
低频时码信号正交解调技术研究 总被引:2,自引:1,他引:1
采用正交叠加和正交采样技术,提出了更大程度上数字化的低频时码信号正交解调的设计方案。同时,分析了这种解调方法的虚假抑制和抗镜像干扰能力。分析表明所论述的解调技术易于实现数字化,且成本低廉,具有一定的实用价值。 相似文献