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101.
102.
熊大闰 《紫金山天文台台刊》2003,(2)
贯穿对流是恒星演化理论长期未获很好解决的理论问题。尽管它已有近五十年的研究历史 ,但至今人们对贯穿对流仍存在很多的错误的理解。究其原因是因为人们对贯穿对流的理解依然停留在唯象的混合长理论图象上。根据一种非局部对流理论 ,我们揭示了贯穿对流区的结构。在太阳下部的贯穿对流区 ,温度梯度是亚绝热的 ,但是是超辐射的。本文还对恒星对流理论给出了一个简短的评述。 相似文献
103.
Christopher A.Tout 《中国天文和天体物理学报》2007,(2)
Based on previous works of OPAL, we construct a series of opacity tables for various metallicities Z=0, 0.000 01, 0.000 03, 0.000 1, 0.000 3, 0.001, 0.004, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08 and 0.1. These tables can be easily used in Eggleton's stellar evolution code in place of the old tables without changing the code. The OPAL tables are used for log10(T/K) > 3.95 and Alexander's for log10(T/K) < 3.95. At log10(T/K) = 3.95, the two groups' data fit well for all hydrogen mass fractions. Conductive opacities are included by reciprocal addition according to the formulae of Yakovlev and Urpin. A comparison of 1 and 5 M models constructed with the older OPAL tables of Iglesias and Rogers shows that the new opacities have most effect in the late stages of evolution, the extension of the blue loop during helium burning for intermediate-mass and massive stars. 相似文献
104.
三江地区盐源-丽江及川滇地块的地震活动与构造运动态势 总被引：10，自引：3，他引：7
阐述了盐源－丽江地块的存在及其边界，根据遥感影像等资料论述了该地块范围内强烈地震活动和构造运动，并提出盐丽、川滇等地块的构造及运动态势应是在印度模块北移、压入欧亚板块并与之夹挤的作用下，使其间部分地球物质向东、东南或转向西南移（流）动的表现。 相似文献
105.
病态平差模型直接解算方法的研究 总被引：15，自引：3，他引：12
基于矩阵的SVD理论，通过修改设计阵的奇异值，提出了若干种直接解算病态(满秩或秩亏)观测方程的方法，以改善设计阵的病态性，提高参数估值的稳定性和准确性。理论分析和数值计算的结果验证了这些解算方法的优良性。 相似文献
106.
This study on the sectional and vertical distribution of dissolved oxygen (DO) and the O_2 fluxes acrossthe sea-air interface in East China Sea (ESC) waters shows that the waters were in steady state and thatthe difference of DO was great in upper and bottom waters in Apr. 1994; but that seawater mixingwas strong and the difference of DO was small in upper and bettom waters in Oct. 1994. The above con-dusions were specially obvious in continental shelf waters under 100m. The DO maximum in subsurfacelayer waters appeared only at several stations and in general the DO in the waters decreased with depth.The horizontal distributions of O_2 fluxes across the sea-air interface appeared in stripes in Leg 9404 whenmost regions covend were supersaturated with O_2. seawater to air flux wn large, and that on section No.1was 1.594 L/m~2·d. The horizontal distribution of O_2 fluxes across the sea-air interface appeared lumpy inLeg 9410, when most regions covered were unsaturated with O_2. O_2 was dissolved from air 相似文献
107.
燃煤电厂废弃物中的砷对周围环境的影响 总被引：3，自引：0，他引：3
通过对电厂的煤、除尘器飞灰、渣、烟囱排放的不同粒度的细小飞灰中的砷进行分析对比，并对煤、除尘器飞灰和渣进行淋滤实验研究发现。砷在飞灰中富集，在渣中亏损，并且在细小飞灰中明显富集，20μm以下的飞灰中分布均匀。煤和渣中的砷有一定的迁移性，飞灰中的砷相对迁移性低，煤中部分砷与铁锰氧化物相关，飞灰和渣中的砷主要与碳酸盐及表面氧化物离子相关，还有部分易进行离子交换，在酸性甚至中性务件下，飞灰和渣中的砷与周围的水等介质可以部分发生交换从而进入环境。煤中约有三分之一的砷会直接挥发入空气中，随烟气排放的细小飞灰中砷明显富集且其中的相当一部分是2．5μm以下的颗粒，对大气环境及人体的潜在影响不容忽视，适当的措施减少砷的排放量很有必要。 相似文献
108.
Tang Dengyin Zhang Shifeng Institute of Geography CAS Beijing People''s Republic of China 《地理学报(英文版)》1997,(2)
Ｉ.Ｂａｃｋｇｒｏｕｎｄ1.ＮａｔｕｒａｌｃｏｎｄｉｔｉｏｎｓＴｈｅｉｒｒｉｇａｔｅｄａｒｅａｏｆｎｏｒｔｈｗｅｓｔＳｈａｎｄｏｎｇＰｒｏｖｉｎｃｅｂｙｃｈａｎｎｅｌｉｎｇＹｅｌｌｏｗＲｉｖｅｒｉｓａｖｅｒｙｉｍｐｏｒｔａｎｔｉｒｒｉｇａｔｅｄｒｅｇｉｏｎｉｎｔｈｅｌｏｗｅｒｒｅａｃｈｅｓｏｆＹｅｌｌｏｗＲｉｖｅｒ,ｉｎｃｌｕｄｉｎｇ27ｃｏｕｎｔｉｅｓａｎｄｃｉｔｉｅｓｗｉｔｈａｎａｒｅａｏｆ29,700ｋｍ2,ｏｒ19.3ｐｅｒｃｅｎｔｏｆｔｈｅｔｏｔａｌｏｆＳｈａｎｄｏｎｇＰｒｏｖｉｎｃｅ.Ａｍｏｎｇｗｈｉ… 相似文献
109.
张北6.2级地震前的卫星热红外异常 总被引：24，自引：0，他引：24
利用张北地震前 1个月华北北部 (37～ 42°N,1 1 3～ 1 1 9°E)的气象卫星 NOAA/ AVHRR热红外遥感资料 ,提取震前热红外温度异常 ,研究其时空变化的过程和特征 ,并对热红外温度异常与地震的关系进行初步的探讨。结果表明 ,在张北地震前 1 3天沿张家口 -渤海断裂带确有显著的热红外温度异常出现。异常区域呈条带状 ,且与 NW向地质构造一致 ;温度异常的动态变化可大致分为初始、平缓发展和临震加速 3个阶段。将热红外温度异常作为一种临震前兆对强震的预报具有一定的映震效应 相似文献
110.
Rock Deformation, Component Migration and ^18O/^16O Variations during Mylonitization in the Southern Tan-Lu Fault Belt 
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下载免费PDF全文 YANG Xiaoyong LIU Deliang FENG Min YU Qingni WANG Kuiren 《《地质学报》英文版》2007,81(2):297-311
This paper discusses the relationship between the volume loss, fluid flow and component variations in the ductile shear zone of the southern Tan-Lu fault belt. The results show that there is a large amount of fluids flowing through the shear zone during mylonitization, accompanied with the loss of volume of rocks and variations of elements and oxygen isotopes. The calculated temperature for mylonitization in different mylonites ranges from 446 to 484℃, corresponding to that of 475 to 500℃ for the wall rocks. The condition of differential stress during mylonization has been obtained between 99 and 210 MPa, whereas the differential stress in the wall rock gneiss is 70-78 MPa. The mylonites are enriched by factors of 1.32-1.87 in elements such as TiO2, P2O5, MnO, Y, Zr and V and depleted in SiO2, Na2O, K2O, Al203, Sr, Rb and light REEs compared to their protolith gneiss. The immobile element enrichments are attributed to enrichments in residual phases such as ilmentite, zircon, apatite and epidote in mylonites and are interpreted as due to volume losses from 15% to 60% in the ductile shear zone. The largest amount of SiO2 loss is 35.76 g/100 g in the ductile shear zone, which shows the fluid infiltration. Modeling calculated results of the fluid/rock ratio for the ductile shear zone range from 196 to 1192 by assuming different degrees of fluid saturation. Oxygen isotope changes of quartz and feldspar and the calculated fluid are corresponding to the variations of differential flow stress in the ductile shear zone. With increasing differential flow stress, the mylonites show a slight decrease of δ^18O in quartz, K-feldspar and fluid. 相似文献