从地震震害中看“隔震现象”

本文在对多次地震震害资料进行研究分析的基础上,对其中符合现代隔震原理或思想的震而不倒的现象进行了分析,并将其划归为5类:(1)柱基“铰结”隔震消能;(2)结构底部柔性防潮层或薄弱层滑移隔震;(3)殿基、墙基或塔基滑移隔震消能;(4)柔性地基隔震消能;(5)采用长周期柔性结构。针对每一类情况分别进行了剖析,并列举了一系列震害实例。最后对现代隔震技术发展中所存在的问题及发展方向提出了看法。     

Lithium depletion in late-type dwarfs

Using a self-consistent dynamic theory of non-local convection, the atmospheric lithium-abundance depletion values of a series of stellar evolutionary models with     are calculated, and the results show that the general observed properties of lithium abundance in lower-main-sequence stars can be reproduced by overshooting mixing and gravitational settling. After a careful study of the mechanisms of lithium depletion in stars, it is concluded that overshooting mixing and microdiffusion induced by gravitational settling and radiative acceleration are the two primary depletion mechanisms: for warm stars with     (or     ) microdiffusion dominates, while it is the other way round for cooler objects with     (or     ).     

浅谈如何撰写观众喜爱的电视天气预报节目演播稿

从撰写市级演播稿的工作实践,找出几点撰写观众喜爱的电视天气预报节目演播稿的经验体会:撰稿者要不断地学习,全面掌握和累积气象及其他学科等多方面的知识,深入了解观众的需求,用"心"去策划,运用娴熟的文学技巧,从通俗易懂的角度向观众传递信息,才能写出好的演播稿件。     

NCEP FNL全球分析资料的解码及其图形显示

美国环境预报中心（NCEP）的FNL资料分辨率较高且融合了大量的观测资料及卫星反演资料,被广泛用于数值模式及天气、气候的诊断分析研究中。本文对该类资料的解码程序及绘图时所需控制文件、索引文件生成方法进行介绍,通过一系列批处理命令,可以进行大量FNL资料的解码及绘图处理,为科研工作者在资料内容提取和图形显示等方面的工作提供一定的参考。     

1m红外太阳望远镜光电导行系统中像场旋转的分析

云南天文台1m红外太阳望远镜(YNST)光电导行系统是基于检测太阳像在面阵CMOS图像传感器上的偏移量作为反馈控制信号的高精度闭环跟踪系统[1]。由于YNST是一个地平式装置,在太阳像偏移检测量中存在着像场旋转量,为了获取稳定清晰的太阳像,必须对检测量进行消旋[2]才能达到光电导行系统的跟踪要求。根据球面天文学及天体测量学的知识并结合导行镜的光学系统,推导了光电导行系统中像场旋转的变化规律并对其进行模拟分析。     

湖北银洞沟银矿床地质特征与成因类型

湖北银洞沟矿床是中国为数不多的较为典型的大型银矿床。文中系统总结了该矿床的地质特征,初步提出了矿床的成因类型。研究结果表明:银洞沟矿床产于秦岭造山带东南部武当群变质火山岩中,矿体受韧性剪切带控制,矿石类型主要为石英脉型和少量蚀变岩型,围岩蚀变矿物组合主要为石英、铁白云石、白云母、钠长石、绿泥石、黄铁矿等,成矿流体特征为低盐度、低密度、富含CO2±CH4±N2的水溶液,矿床上部为低品位银金矿体,中部为高品位银金矿体和少量铅锌矿体,深部银品位降低,金品位增高,同时出现较厚大铅锌矿体。其地质特征与典型的造山型矿床一致,表明其为一造山型银矿床,矿床矿化分带符合造山型矿床成矿模式——地壳连续模型,因此应该充分重视寻找矿山深部金、铅、锌、铜、钼等接替资源。     

粘土中圆形隧道上限解的研究

根据极限分析上限理论,基于Davis等人提出的隧道垮落模型,提出了剪切区参数α等于1时的新的隧道垮落模型。由不可压缩性条件和速度连续性条件求出了剪切区速度和间断线表达式,计算了该模型间断线上能量耗损、剪切区能量耗损和总外力所做的功。利用功能原理,求出了稳定率的表达式,并计算了相应的稳定率。从求解结果来看,所得上限解小于Davis等人的结果,因而该上限解将更接近真实解。从与实验结果比较来看,该上限解位于实验值附近,能与实验结果比较好地吻合,从而说明该模型更加接近真实隧道垮落情形。该上限解可为隧道支护提供理论依据。     

Chemical Zone of Nephrite in Alamas,Xinjiang, China

The Hetian deposit, located south of the Tarim Basin in Xinjiang, China, is one of the world's largest dolomite-related nephrite deposits. In the Alamas orebody of the deposit, nephrite occurs as veins or lenses along faults or fissures of the adjacent dolomitic marble. Chemical analyses using electronic microscope probe analysis and X-ray fluorescence spectroscope were carried out on nephrite and dolomitic marble samples collected from a cross section in Alamas to investigate zonal structure of the orebody. The nephrite in Alamas is predominately composed of tremolite with minor calcite, titanite and phlogopite, and that dolomitic marble is relatively pure with a FeO content less than 0.20 wt. %. Contents of color-inducing elements, such as Fe, Mn, and Cr, increase gradually as color changes from white through white-green and then to green, resulting in the formation of color-distinctive zones. Tremolite grain size increases as color changes from white through white-green to green. The trend may be consistent with temperature changes from dolomitic marble to granodiorite, which, in turn, suggests that both change in color from white to green and variations of grain size with increasing temperature resulting in formation of the nephrite zonal structure. Both nephrite zonal structure and minor minerals, such as calcite, titanite and phlogopite found in the contact, indicate that this dolomite-related nephrite orebody is of a metasomatic origin under assumed pressure of 100–200 MPa and temperature <550°C.     

Calcium carbonate precipitation induced by a bacterium strain isolated from an oligotrophic cave in Central China

A heterotrophic Bacillus sp. strain (5C-1) was isolated from Heshang cave, an oligotrophic karst cave in the middle reaches of Yangtze River, and identified by BIOLOG and 16S rDNA sequencing. Bacterially induced formation of calcium carbonate by 5C-1 was investigated in several comparative experimental sets with or without the cell and extracellular enzymes. The temporal variations of both the amount of the precipitates and the pH values of the solution were measured by a spectrophotometer and a pH meter, respectively. The morphological characteristics of the calcium carbonate precipitates were observed with environmental scanning electronic microscopy (ESEM). The growth of 5C-1 was found to greatly promote the pH value of the liquid medium in the first 2 days, which favors the formation of calcium carbonate. No precipitates were formed with the pH value lower than 8.6, though the pH value was demonstrated to be not the only factor controlling the formation of the calcium carbonate. The accumulation of extracellular polysaccharide substance was observed to favor the precipitate formation. Only when both factors reached a threshold did the precipitates form with the addition of CaCl₂. Cells and extracellular enzymes were not the factors that limit the precipitate formation in our microbial systems. The precipitates of a variety of morphological features including dumb bells, peanuts, irregular and spherical and rhombic forms were mainly observed in our microbial systems but not in the chemical control system. Interestingly, imprints of bacterial cells and spores were observed to be present on the surface of the precipitates of a peanut or a dumb bell form, probably indicative of the microbial escaping mechanism during the mineralization of calcium carbonate.