科尔沁湿草甸参考作物蒸散发模拟分析

为探明气候变化下干旱半干旱地区湿草甸参考作物蒸散发(ET₀)影响因子,使用FAO 56 P-M模型对科尔沁湿草甸ET₀进行模拟,利用涡度相关系统对模型的适用性进行评价,并通过通径分析及指标敏感性分析对ET₀的影响因子进行辨识。结果表明:(1)小时尺度模拟精度最高,日尺度次之,月尺度较差,小时尺度上晴、阴、雨3种天气条件下模拟效果不同,晴天最优,阴雨天较差。(2)ET₀年内变化呈单峰曲线状,生长季明显高于非生长季,集中在3—10月,占全年89.79%。生长季典型晴天ET₀逐小时分布特征遵循倒“U”单峰型变化规律。(3)通径分析结果显示,对ET₀的通径系数以及对回归方程估测可靠程度E的总贡献均表现为VPD(饱和水汽压差) > T_min(最低气温) > R_n(冠层表面净辐射)>u₂(2 m高度风速),即VPD为影响ET₀最重要的因子;指标敏感性分析中,在去除VPD后引起的E变化最大,说明ET₀对VPD的变化最为敏感,其次为u₂、T_min和R_n。     

利用卫星云图资料制作热带气旋预报路径的一种算法

根据台风生成后在云场中移动的环境条件,引入一个环境作用于台风中心的热力梯度力方向,用该热力梯度力方向与当前台风的移动方向相结合,研究台风移动过程的变化规律,寻找一种简易可行的台风路径预报方法．经过多年实践,本文揭示出台风中心未来沿着当前移动方向与环境作用于台风中心的热力方向合成移动的基本规律：当前台风中心移向与前方晴空区中轴线相交时,台风沿着当前移向前进到与阻挡轴线相交点相距4个纬距的位置时便发生偏转,逐渐与阻挡轴线走向趋于一致;若当前台风中心距相交点的距离小于或等于4个纬距时,则从当前位置发生偏转．文中利用以上规律研制出台风移向变化方程和移动轨迹方程．     

Identifying the scope of the Lhasa Metropolitan Area based on a spatial field energy model

The cultivation and development of modern metropolitan areas with the aim of establishing new regional centers with competitive edge is a key objective for the new-type urbanization directions in China. The construction of the Lhasa Metropolitan Area is of great significance for the promotion of the South Asia Channel, the ‘Belt and Road' initiative, the Bangladesh-China-India-Myanmar Economic Corridor, the Himalaya Economic Cooperation Zone, and for rapid development and long-term stability of the Qinghai-Tibet Plateau. This paper examines the scope of the Lhasa Metropolitan Area including Chengguanqu(Chengguan District), Doilungdeqen, Dagze, Lhunzhub, Damxung, Nyemo, Quxu, Maizhokunggar, Samzhubze Qu(Samzhubze District), Gyangze, Rinbung, Bainang, Nedong, Gonggar, and Zhanang using a spatial field energy model that combines nodality and accessibility indices and considers multiple indicators including traffic flow between cities. By combining factors such as the natural background, population agglomeration, the social economy, infrastructure construction, and the urban spatial structure of the Lhasa Metropolitan Area, it is proposed to build a bow-and-arrow-shaped urban system with ‘one core, two centers, one axis, and two wings' along the valleys and the transportation trunk lines of the area. The study advocates the construction of a pure land industrial system comprising a green cultural and tourism-oriented plateau.     

Stress‐dependent hardening and failure surfaces of dry sand

During several triaxial compression experiments on plastic hardening, softening, and failure properties of dense sand specimens, it was found on various stress paths that the size of the failure surface was not constant. Instead, it changed depending on the current state of hydrostatic pressure. This finding is in contrast to the standard opinion consisting of the fact that the failure surface remains constant, once it has been reached during an experiment or in situ. In general, the behaviour of cohesionless granular‐material‐like sand is somehow characterised in between fluid and solid, where the solid behaviour results from the angle of internal friction and the confining pressure. Although the friction angle is an intrinsic material property, the confining pressure varies with the boundary conditions, thus defining different solid properties like plastic hardening, softening, and also failure. Based on our findings, it was the goal of the present contribution to introduce an improved setting for the plastic strain hardening and softening behaviour including the newly found yield properties at the limit state. For the identification of the material parameters, a complete triaxial experimental analysis of the tested sand is given. The overall elasto‐plasticity concept is validated by numerical computations of several laboratory foundation‐ and slope‐failure experiments. The performance of the proposed approach is compared with the standard concept of a constant failure surface, where the corresponding yield surfaces are understood as contours of equivalent plastic work or plastic strain. Copyright © 2012 John Wiley & Sons, Ltd.     

Tectonic interpretation of metamorphic tectonites: integrating compositional mapping,microstructural analysis and in situ monazite dating

Interpreting tectonic histories from metamorphic tectonites requires an understanding of the linkages and feedbacks between deformation and metamorphism. Relationships between deformation and metamorphism can be divided into two broad groups: active and passive. Active relationships involve direct interactions whereby deformation directly influences metamorphic reactions or metamorphism directly affects the rate or style of deformation. One of the most important ‘active’ relationships is the role that deformation plays in helping to remove unstable reactant phases and to promote the growth of stable product phases. Passive relationships are correlations or linkages that allow the deformation history to be integrated with the metamorphic history. Compositional mapping of major and accessory phases and especially maps of larger thin section domains are particularly valuable for evaluating strain partitioning, scales of equilibrium, relationships between metamorphic textures and deformational fabrics, and in particular, for interpreting geochronological data. Petrological pseudosections are an increasingly utilized tool for interpreting microtextures and for linking deformation, metamorphism, and large‐scale tectonics. In situ geochronology and petrological analysis of chronometer phases (i.e. monazite, xenotime, titanite, allanite, etc.) are a critical part of tectonic analysis of metamorphic rocks. The electron microprobe plays an essential role in characterizing chronometer phases and placing them into the context of silicate fabrics and textures.     

麻粒岩p—T—t轨迹的研究现状

综述了近年来麻粒岩中p-T-t轨迹的研究现状。内容涉及到麻粒岩相变质作用的温压条件及时间跨度,同时指出:结合岩石中的矿物组合、后成合晶及反应结构,利用矿物温压计是目前确定p-T-t轨迹的主要手段。     

超高压变质作用研究现状及问题

本文从超高压变质作用的矿物学、Ｐ－Ｔ－ｔ轨迹和超高压地体抬升、保存机制三个方面总结了近年来超高压变质作用研究所取得的重要进展和存在的问题。超高压变质作用的矿物学研究正在向深入发展，其Ｐ－Ｔ－ｔ轨迹具有三种成因类型。而其超高压地体的抬升、保存机制则是争论的焦点，其中增生楔模式（Ｐｌａｔｔ，１９８７）和连续俯冲─仰冲机制较好地解释了抬升过程，但也存在一些问题需进一步研究。     

GPS工程控制网最优化设计的研究

本文讨论了GPS工程控制网的最优化设计问题;通过对GPS工程控制网的精度和可靠性分析,建立了应用点位精度矩阵相关性优化GPS网的数学模型;针对解算中存在的问题,提出了最短路径法寻找整数变量线性规划问题的最优解。     

多功能雾化室在ICP—AES中的应用研究

本文研究了一种多功能雾化室装置,以探索ICP-AES技术中溶液进样的新方式;并对雾化系统的主要参数进行测试,取得最佳的匹配条件。该雾化室装置包括旋流雾化、循环雾化和氢化-雾化等系统,可在同一操作条件下进行工作,适应多种分析的需要。并可任意选择合适的雾化射程来增强元素谱线强度的信背比和雾化的稳定性,以达到改善分析的精密度和检出限。     

组建云南天文时纬测震网的意义及可行性

本文简要地介绍了光学天文时纬残差在地震前夕出现短期异常波动的现象，认为光学天文时纬观测可为地震短期预报提供有价值的信息。作者认为在地震活动性较强的云南地区，组建一个天文时纬测震网是有意义的，本文讨论了其可行性及有关问题。