Chalcopyrite Intergrowths in sphalerite in the Meixian Lead—Zine Deposit,Fujian Province and their Metallogenic Significance   总被引：2，自引：0，他引：2  

顾连兴  周兵等 《中国地球化学学报》1998,17(4):311-319

Ore textures and electron microprobe analyses show that in addition to highly scattered blebs in sphalerite grains,intergrown chalcopyrite also occurs as rods,myrmekites and lamellae aligned along cleavages and twin boundaries of the host sphalerite.The majority of the intergrowths could have been formed by replacement of sphalerite by chalcopyrite,albeit part of them may have resulted from exsolution,Not only copper,but also iron were introduced into the sphalerite by replacive fluids.While the front of the replacing fluid was moving forward through a sulphide orebody,Zn and Pb were dissolved and Cu was precipitated,resulting in zonal refining of the sulphide ores,The remobilized zinc and lead were precipitated at favourable sites with changed physico-chemical conditions .This is a possible mechanism for the formation of copper-poor zinc and lead ores above or lateral to the copper orebodies in some of the massive sulphide deposits reworked and overprinted by late-stage granites and their hydrothermal fluids.  相似文献   

女姑山跨海桥基施工用钢平台设计   总被引：1，自引：0，他引：1       下载免费PDF全文

顾元威  于吉太 《探矿工程》1998,(1):33-35

结合青岛女姑山跨海桥基工程实践,介绍海滨钢平台设计的基本程序与方法。  相似文献   

An Interpretation of the Non-Tidal Secular Variation in the Earth Rotation: the Interaction Between the Solar Wind and the Earth's Magnetosphere     

Zhennian Gu 《Astrophysics and Space Science》1998,259(4):427-432

The long period variation of the earth rotation is generally explained by the tidal friction. The tidal friction, however, is not the only source to influence the earth rotation in long term. In this paper, by means of the interaction between the solar wind and the magnetosphere of the earth, the additional magnetic pressure will exist in the magnetic tail due to the crowding and sparseness of the magnetic lines in the consideration of the earth rotation, which could be considered as a source of effecting the long term variation of the earth rotation. It is shown in this paper that this mechanism can produce angular deceleration of the Earth rotation in the magnitude of ω = −1.7 × 10-22 s-2. This result might be a prompt to search for other sources in the secular variation of the rate of the Earth rotation variation further in order to regulate the observed result with the theoretical one. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Multi-object fiber-fed spectroscopy     

P. Felenbok  J. Guérin  R. Bellenger  M. Dreux  A. Fernandez 《Astrophysics and Space Science》1990,171(1-2):297-300

We are presenting a multi-object instrument for spectrography in a large field. It is of the arm design as MX or ARGUS. The MEFOS (Meudon-ESO Fiber Optical System) version is built to be used at the ESO 3.60 m prime focus with the triplet corrector. The FIFI (Franco-Italian Fiber Instrument) version, a copy of MEFOS, is shared between the Bologna Observatory and the Paris-Meudon Observatory and will be used, on a visitor basis, at the CFHT prime focus. The instrument carries 30 independent arms with an imaging capability on each arm. It is a modular design with its electronic implemented on each arm. The system is under control of anti-collision software and the whole instrument is driven by an PC/XT-type computer.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.  相似文献   

On the relationship between tropical cyclone size and environmental helicity in the South China Sea          下载免费PDF全文

Min Li  Kekuan Chu  Jian-Feng Gu  Zhe-Min Tan 《大气和海洋科学快报》2022,15(4):100205

In this study, the impact of environmental factors on tropical cyclone (TC) outer-core size was investigated for both migrating and local TCs in the South China Sea during the period 2001–2019. Among all the thermodynamic and dynamic factors, the low-level environmental helicity showed the strongest positive correlation with TC outer-core size. Large helicity favors the development and organization of convection in TCs, and the corresponding strong inflow and large angular momentum fluxes into the system is beneficial for the maintenance and enlargement of TC outer-core size. Besides, the asymmetric distribution of helicity may account for the asymmetry of TC outer-core size. Therefore, the environmental helicity, as an integrated dynamic factor, can provide an alternative view on TC outer-core size.摘要本文利用2001–2019年间的ERA5再分析数据集和热带气旋 (TC) 最佳路径观测, 分析了中国南海TC的外围尺度与环境变量之间的关系. 研究发现, 低层环境螺旋度与TC外围尺度具有显著的正相关. 大的环境螺旋度有利于TC外围对流的增强和组织化, 与之对应的径向入流和角动量输送有利于TC外围尺度的维持或扩张. 此外, 螺旋度的非对称分布与TC外围尺度的非对称性结构也密切相关. 环境螺旋度作为一个包含TC外围对流强度和组织化程度等信息的综合动力因子, 为理解TC外围尺度变化提供了不同的视角.  相似文献   

高速公路团雾分级预警研究     

卢振礼  杨成芳  郑宗杰  等. 《气象与环境科学》2022,45(1):103-111

团雾和高速公路团雾的定义内涵外延尚未统一,没有标准定义。为有效预防高速公路团雾天气灾害,减少因高速公路团雾所造成的交通事故,有必要规范高速公路团雾分级预警标准。基于高速公路团雾的水平能见度和水平尺度等监测数据,借鉴部分学者专家的意见和建议,确定团雾和高速公路团雾的定义。分析高速公路团雾的特征、成因、时空分布及团雾的危害,统计分析高速公路团雾多发路段的交通事故数据资料与AWMS气象监测数据资料,确立高速公路团雾与车辆交通安全性关系。依据同车道前后车辆的相对停车视距和安全停车距离等分析,评估车辆在不同水平能见度数值条件下,行驶在团雾区域内外车辆发生交通事故的危险性大小,遵照相关法律、条例、标准及其规范,按水平能见度数值范围和覆盖路面长度划分高速公路团雾预警等级。研究结果表明:(1)高速公路团雾的水平尺度一般小于5 km,水平能见度通常小于200 m。(2)高速公路团雾具有多发性,时空分布不均,多发生于当日22时次日08时。(3)高速公路团雾的事故率高,造成的交通事故比较严重。(4)可以根据团雾特征和潜在危害性确定团雾和高速公路团雾定义的内涵外延,给出术语定义。(5)可根据高速公路团雾的水平能见度、交通事故、停车视距等分析,划分预警级别,规范监测和预报预警服务,减少交通事故的发生。  相似文献   

Measurement of ecological capital of Chinese terrestrial ecosystem based on remote sensing   总被引：5，自引：0，他引：5  

PAN Yaozhong  SHI Peijun  ZHU Wenquan  GU Xiaohe  FAN Yida & LI Jing Key Laboratory of Environmental Change  Natural Disaster of the Ministry of Education of China  Beijing Normal University  Beijing  China Correspondence should be addressed to Fan Yida 《中国科学D辑(英文版)》2005,48(6):786-796

The biosphere of the Earth is the material founda-tion of human survival and development.With the increasing problems of the resources,the environment and population,most countries in the world have paid special attention to the measurement and evaluation of ecological capital,which refers to the sum of the direct natural resources value and the indirect ecosystem services value.Ecological capital depends on not only the quality of the national ecological environment,butalso the social recogni…  相似文献   

Comparison between the polar coordinates determined by different observational techniques     

Gu Zhen-nian  Wang Shu-he  Zheng Da-wei 《Chinese Astronomy and Astrophysics》1983,7(4):322-330

The main characteristics of several polar coordinate systems in present use are compared. The systematic differences between the classical technique (BIH 68) and the new technique (DMA and IASOM) are analysed in depth and their external errors estimated.  相似文献   

西北太平洋137°E断面海流的纬向体积输送   总被引：8，自引：0，他引：8  

顾玉荷 《海洋与湖沼》1996,27(1):79-85

利用日本气象厅1967－1989年间沿137°E断面观测到的水文和海流资料，计算了该断面上1°S－34°N的纬向体积输送。纬向体积输送的明显特点是复强冬弱，无论是多年平均的还是个别年份的，不管是东向输送分量还是西向输送分量，该特征都是非常明显的。净输送量有非常大的年际变化，70年代以向西输送为主，80年代则以向东输送为主，峰值出现在ElNio事件前后，二者有一定的关系。  相似文献   

潮汐流动中污染物排放的一种远区计算模型   总被引：7，自引：0，他引：7  

顾杰  匡翠萍 《海洋工程》1996,(1)

本文建立了一个适合于潮汐流动中污染物排放的远区动态平面二维数值计算模型。该模型的计算特点是将流场和浓度场分开计算，即所谓“非耦合解”，运用有限节点法计算了流场，用改进的有限节点法计算了浓度场。该模型应用于长江大厂镇江段，其计算出的流场和该江段典型污染物Ｆ－的浓度场与实测一致，在此基础上，用设计潮计算了一个污水排江方案，确定了其影响范围  相似文献