抚顺浑南地区金矿控矿地质条件分析

抚顺浑南地区成矿条件有利,找矿信息较多,但以往相应的地质科研工作投入甚少。作者以该区找矿勘查资料为依据,着重阐述了成矿地质背景,并系统分析了该区成矿地质条件、矿体地质特征以及分布规律,同时提出了进一步找矿的方向。     

锦屏电站坝厂区卸荷岩体力学参数研究

选择具有代表性的区块,根据结构面的性状和规模拟定模型层次和尺寸,建立岩体数值仿真模型,通过计算机数值仿真,采用卸荷非线性力学理论对锦屏电站坝厂区岩体进行卸荷岩体宏观力学特性及参数的数值分析;同时,用RMR法和BP神经网络法对岩体宏观力学特性及参数进行分析,综合确定岩体力学参数,为设计部门提供设计参考依据.     

基于地面三维激光扫描的三峡库区危岩体监测

三峡水库周期性蓄水改变了岸坡内的地下水渗流场和应力场,降低岩土体的剪切强度,对库岸边坡、岩体稳定性影响很大。以往库区岸坡岩体形变监测主要通过设置固定点进行观测,难以发现岩体整体变化情况。地面三维激光扫描方法能获取岩体整体表面厘米精度的点云数据,具有无需接触目标、获取速度快、精度高等特点,非常适合库区高陡危岩体表面三维形变监测。以巫山箭穿洞危岩体为例,采用地面三维激光扫描方法对箭穿洞危岩体进行了为期2年（2017—2018年）共3期监测,以第一期观测目标周围稳定岩体数据为基准,对数据进行重叠点云迭代配准,点云配准精度优于±2.7 cm。针对箭穿洞危岩体在观测时段内的变化情况,构建危岩体区域的基准不规则三角网模型,以点到基准面最近距离法结合危岩体变化区间分析其变形。通过对比分析箭穿洞危岩体3期观测数据,发现相对于2017年,2018年箭穿洞危岩体左侧岩体有变形趋势;在库区蓄水阶段,危岩体局部多处存在明显凹陷变化,局部因蓄水影响发生约−0.03～−0.07 m变形。结果证明三维激光扫描技术在库岸高陡边坡形变监测中的有效性,为三峡库区高陡危岩体形变监测及地质灾害防治工作提供了参考。     

雷击风险评估中Lo损失因子在多线路系统下的细化和改进

2008年推广施行的新国标GB/T 21714.2已广泛应用于各地雷击风险评估业务中。但在实际应用过程中人们也发现用其建立评估模型时,标准的一些简约化约定,使得其计算结果不够精准,特别是描述和处理也显得越来越困难,影响和制约了它的应用范围和前景。为此,本文针对带有多种电气和电子系统的复杂结构建筑,提出按其进线分布特点,对Lo损失因子取值方法进行改进(下文均称"Lo优化取值法"),为多线路进线建筑物的雷击风险管理提供更细化的依据和算法,并举例证实。结果表明:细化考虑不同线路的Lo对于建筑物雷击风险评估更为切近真实。     

变形岩体软弱破裂带的处理技术

在研究完成变形岩体软弱破裂带可灌性的基础上,采用旋喷注浆技术进行直接加固处理,提高破裂带的内聚力和内摩擦角,实践证明,抑制了岩体的变表,防止了滑坡的产生。     

上海市防震减灾应急决策信息系统-GPS的应用

为了适应上海经济建设高速发展和超大型城市防震减灾工作的需要,建立城市防震减灾应急决策信息系统已成为必然．本文将地理信息系统（GIS）技术应用于上海市防震减灾应急决策信息系统（宝山试点区）,介绍了此系统各功能模块的结构和作用．此系统由７个功能模块组成,即地震地质基本信息、地震灾害快速评估子系统、地震应急决策信息子系统、信息查询、系统维护管理、帮助和退出等．其核心部分是地震灾害快速评估子系统和地震应急决策信息子系统．本文还介绍了彩红外航片遥感技术在上海市防震减灾应急决策信息系统中的应用．     

Lateral tidal mixing in the Antarctic marginal seas

Tidal mixing plays an important role in the modification of dense water masses around the Antarctic continent. In addition to the vertical (diapycnal) mixing in the near-bottom layers, lateral mixing can also be of relevance in some areas. A numerical tide simulation shows that lateral tidal mixing is not uniformly distributed along the shelf break. In particular, strong mixing occurs all along the Ross Sea and Southern Weddell Sea shelf breaks, while other regions (e.g., the western Weddell Sea) are relatively quiet. The latter regions correspond surprisingly well to areas where indications for cross-shelf exchange of dense water masses have been found. The results suggest that lateral tidal mixing may account for the relatively small contribution of Ross Sea dense water masses to Antarctic Bottom Water.     

Non-point source pollution in Indian agriculture: Estimation of nitrogen losses from rice crop using remote sensing and GIS

The paper presents a detailed understanding of nitrogenous fertilizer use in Indian agriculture and estimation of seasonal nitrogen loosses from rice crop in Indo-Gangetic plain region, the ‘food bowl’ of the Indian sub-continent. An integrated methodology was developed for quantification of different forms of nitrogen losses from rice crop using remote sensing derived inputs, field data of fertilizer application, collateral data of soil and rainfall and nitrogen loss coefficients derived from published nitrogen dynamics studies. The spatial patterns of nitrogen losses in autumn or ‘kharif’ and spring or ‘rabi’ season rice at 1 × 1 km grid were generated using image processing and GIS. The nitrogen losses through leaching in form of urea-N, ammonium-N (NH₄-N) and nitrate-N (NO₃-N) are dominant over ammonia volatilization loss. The study results indicate that nitrogen loss through leaching in kharif and rabi rice is of the order of 34.9% and 39.8% of the applied nitrogenous fertilizer in the Indo-Gangetic plain region. This study provides a significant insight to the role of nitrogenous fertilizer as a major non-point source pollutant from agriculture.     

Yields of Nucleosynthesis from massive and intermediate mass stars and constraints on their final evolution

Nucleosynthetic yields and production rates of helium and heavy elements are derived using new initial mass functions which take into account the recent revisions in O star counts and the stellar models of Maeder (1981a, b) which incorporate the effects of massloss on evolution. The current production rates are significantly higher than the earlier results due to Chiosi & Caimmi (1979) and Chiosi (1979), and a near-uniform birthrate operating over the history of the galactic disc explains the currently observed abundances. However, the yields are incompatibly high, and to obtain agreement it is necessary to assume that stars above a certain mass do not explode but proceed to total collapse. Further confirmation of this idea comes from the consideration of the specific yields and production rates of oxygen, carbon and iron and the constraints imposed by the observational enrichment history in the disc as discussed by Twarog & Wheeler (1982). Substantial amounts of⁴He and¹⁴C, amongst the primary synthesis species, are contributed by the intermediate mass stars in their wind phases. If substantial numbers of them exploded as Type I SN, their contribution to the yields of¹²C and⁵⁶Fe would be far in excess of the requirements of galactic nucleosynthesis. Either efficient massloss precludes such catastrophic ends for these stars, or the current stellar models are sufficiently in error to leave room for substantial revisions in the specific yields. The proposed upward revision of the¹²C (α,γ)¹⁶O rate may produce the necessary changes in stellar yields to provide a solution to this problem. Stars that produce most of the metals in the Galaxy are the same ones that contribute most to the observed supernova rate.     

激光探针等离子体质谱同时测定锆石微区铀—铅年龄及微量元素

建立了一种利用激光探针等离子体质谱技术同时原位测定锆石Ｐｂ－Ｐｂ及Ｐｂ－Ｕ年龄和２５个微量元素的快速分析方法。Ｐ的检出限为１４μｇ／ｇ,Ｓｃ的检出限为３μｇ／ｇ,Ｒｂ、Ｎｂ、Ｂａ稀土元素Ｎｄ、Ｇｄ、Ｄｙ、Ｅｒ及Ｙｂ的检出限为０．１￣０．３μｇ／ｇ,Ｐｂ的检出限０．５μｇ／ｇ,其它稀土元素及Ｓｒ、ｙ、Ｈｆ、Ｔａ、Ｔｈ和Ｕ的检出限为１０￣９０ｎｇ／ｇ。方法对绝大多数微量元素的相对标准偏差为５￣１５％;