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411.
Ar-Ar等时线的局限及Cl-Ar等时线的潜力   总被引:2,自引:0,他引:2  
王松山  桑海清  裘冀 《地球学报》1997,18(Z1):272-274
矿物中普遍含有数量不等的过剩40Are,它主要赋存在阴离子空缺部位和流体包裹体中。常规Ar-Ar等时线不完全适用于40Ar/39Ar阶段加热数据。矿物和人造硅胶中40Are和Cl的相关性,预示着Cl-Ar等时线对校正40Are具有较大潜力。  相似文献   
412.
大鹏湾夜光藻种群的季节变化和分布特征   总被引:2,自引:0,他引:2  
于1990年3月-1992年6月对中国南海大鹏湾盐田附近海域的夜光藻种群动态及时空分布进行综合调查。结果表明,夜光藻种群的出现期间一般为每年的1-6月,最早是1991年的12月,数量高峰期为3-5月,种群密度的波动极为显著;调查期间共发生8次赤潮,且都发生在3月初至5月初;大鹏湾夜光藻赤潮的发生特点是,赤潮的发生和消失突然,持续时间短,一般不超过3d;调查海域夜光藻种群的空间分布模式为近岸的高于中央水域的,表面的高于底层的。  相似文献   
413.
Increasing industrial development in the Masan Bay area of Korea over the past decades increased the risk for the survival of marine organisms in the bay area by the deterioration of the water quality. Since living organisms have the ability to adapt contamination-associated stimuli by the alteration of gene expression, changes in proteins can be used as an important criterion for assessing the levels of environmental conditions. In this study, therefore, alterations of the expression of proteins in the muscle ofLimanda yokohamae from Dukdong and Dotsum in the bay area were surveyed and characterized as compared with Haegumgang, which served as a control site. The results demonstrated that the twenty spots detected from Dukdong and Dotsum were similar to each other. Fifteen proteins were found to be predicted or undefined proteins, while five proteins were identified as heavy polypeptide 11 of myosin, apolipoprotein A-I, fibroblast growth factor 17b precursor, G protein-coupled receptor kinase 1 b and bonnie and clyde. These data suggest that local fish in the bay area have dysfunction in muscle physiology including contraction, lipid metabolism, proliferation and differentiation and nervous system.  相似文献   
414.
The main objective of this study was to estimate changes in the area of tidal flats that occurred after sea dike construction on the western coast of South Korea using Landsat-TM images. Applying the ISODATA method of unsupervised classification for Landsat-TM images, the tidal flats were identified, and the resulting areas were quantified for each image. The area of tidal flats from a topographic map published in one year differs significantly from that shown in another, which appears to be attributable to the tide levels at the time of aerial photography. During the study period, the area of tidal flats, as estimated from Landsat-TM images, increased by 4.57 km2 per year in the study areas. The tidal flats in the inner sea of Chunsu Harbor area increased by 200 m2 per zone, while the accumulation for a number of inner sea areas within Asan Harbor area occurred at over 50m2 per zone. The results of this research may serve as the basis of an environmentallyfriendly development plan for tidal flats.  相似文献   
415.
应用煤化工资源指标体系和评价方法,在查明煤化工资源地质背景和资源特性的基础上,研究了六盘水煤田盘北-水城矿区煤化工资源的类别、规模、赋存和分布,探讨了化工煤研究区赋存分布的地质成因,提出以资源为主要依据的煤化工产业布局规划建议.研究区化工煤查明储量42.74×108t,占其煤炭查明储量的62%,化工煤资源中,液化煤1.31×10gt,焦化煤17.45×108t,合成氨煤0.019×108t,气化煤23.96×108t.气化煤和焦化煤是区内化工煤资源的主要类型.  相似文献   
416.
This paper presents an active control algorithm using the probability density function of structural energy. It is assumed that structural energy under excitation has a Rayleigh probability distribution. This assumption is based on the fact that the Rayleigh distribution satisfies the condition that the structural energy is always positive and the occurrence probability of minimum energy is zero. The magnitude of the control force is determined by the probability that the structural energy exceeds the specified target critical energy, and the sign of the control force is determined by the Lyapunov controller design method. The proposed control algorithm shows much reduction of peak responses under seismic excitation compared with the LQR controller, and it can consider the control force limit in the controller design. Also, the chattering problem which sometimes occurs in the Lyapunov controller can be avoided. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
417.
断 层 水害 的发 生 往往 对煤 矿 造成 的损 失 巨大 ,甚 至会 造成 淹 井事 故的 发 生。 但矿 井 一些 运输 巷 、通 风 巷 又必须 穿 越 这些 大 型 导 含水 断 层 。 采取 井 下 钻 孔预 注 浆 的 方式 、选 用单 液 浆 加 入少 量 速 凝 剂的 方 法 ,对 断 层 进行 超 前 止水 、加 固处 理 是十 分可 行 和必 要的 。  相似文献   
418.
Abstract: The Daejang mine is located within the Cretaceous Gyeongsang basin. Mineral paragenesis can be divided into four stages (stages I, II, III and IV) by major tectonic fracturing. Stages I, III and IV are economically barren. Stage II, at which the precipitation of major ore minerals occurred, is further divided into three substages with paragenetic time based on minor fractures and discernible mineral assemblages: substage IIa, marked by deposition of quartz and Fe–sulfides; substage IIb, by introduction of base-metal sulfides within carbonates and some quartz; substage IIc, by quartz and carbonates with various sulfosalts. Fluid inclusion data indicate a complex geochemical evolution of hydrothermal fluids. Both CO2–rich and H2O–rich fluids were trapped in fluid inclusions at stage I and substage IIa. It is suggested that a compositionally heterogeneous fluid was formed by fluid boiling and CO2 immiscibility at temperatures of about 400° to 300°C. Composite lodes of base-metal sul–fides, carbonates and quartz at substage IIb were deposited in open spaces created by fracturing. The fracturing event prompted rapid decreases in pressure and temperature of residual fluids and resulted in retrograde fluid boiling at about 200 bars and 300°–250°C during substage IIb. The progressive loss of CO2 by CO2 effervescence and retrograde boiling from substage IIa and IIb fluids resulted in pH increase and related increase in carbonate activity, causing deposition of abundant carbonates. The change in pH also caused the decrease of stability of hydrogen sulfide with Cu, Zn and Pb chloride complexes (as main transporting agents at Daejang) and resulted in the pricipitation of base-metal minerals. Deposition of Ag– and Sb-bearing sul–fides and sulfosalts of substage IIc occurred at temperatures of about 250° to 150°C from a dominantly aqueous fluid with low salinity (down to 3. 0 equiv. wt % NaCl). At this substage, aqueous fluid formed by mixing with cooler and less saline meteoric groundwater. There is a systematic decrease in caculated δ18Owater values with the mineralization stage (and decreasing temperature) in the Daejang hydrothermal system, from values of about 11% for stage I, through about 4% for stages II and III, to about –3 per mil for stage IV. The result of stable isotope and fluid inclusion studies are interpreted to indicate progressive less evolved and/or unexchanged meteoric water influx of an early hydrothermal system formed by highly evolved meteoric waters.  相似文献   
419.
The major purpose of this study was to develop a predictive model of the yearly frequency of typhoon.Based on historical data, a predictive model of yearly frequency of typhoon that landed in South China was proposed during the season of typhoon using the basic thinking and its algorithm of Pro.jcction Pursuit Regression (PPR). The results show that the predictive precision of PPR model is much better than that of stepwise regression (SR) model.  相似文献   
420.
本文从地面大地网的定向、尺度系统误差的定义及对坐标的影响关系出发,分析了这些系统误差与地面网、卫星网之问转换参数的关系,推导了系统误差对转换参数的影响公式。在此基础上,提出了转换参数的区域性问题,并提出了分离区域性定向误差与尺度比参数的联合平差模型。  相似文献   
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