找矿假设的提出与验证

矿床的形成不为人所能见,由此决定找矿工作必然采取提出找矿假设和对其验证这种形式.文章在分析国内外一些矿床的发现、发展史的基础上,总结和提炼一些找矿假设的思路和方法,及对其验证时应注意的一些问题.     

Impact of Analysis-time Tuning on the Performance of the DRP-4DVar Approach

In this study we extend the dimension-reduced projection-four dimensional variational data assimilation (DRP-4DVar) approach to allow the analysis time to be tunable, so that the intervals between analysis time and observation times can be shortened. Due to the limits of the perfect-model assumption and the tangentlinear hypothesis, the analysis-time tuning is expected to have the potential to further improve analyses and forecasts. Various sensitivity experiments using the Lorenz-96 model are conducted to test the impact of analysistime tuning on the performance of the new approach under perfect and imperfect model scenarios, respectively. Comparing three DRP-4DVar schemes having the analysis time at the start, middle, and end of the assimilation window, respectively, it is found that the scheme with the analysis time in the middle of the window outperforms the others, on the whole. Moreover, the advantage of this scheme is more pronounced when a longer assimilation window is adopted or more observations are assimilated.     

青藏高原油气勘探战略选区和战术突破目标的建议

三陆两槽基础地质认识是长期指导青藏高原油气勘探的基础地质认识,其核心支柱是冈底斯地区晚二叠世—侏罗纪是长期地层缺失或是发育陆相地层的冈底斯古陆。然而最新的青藏高原地质大调查工作识别出了很多原来认为缺失的地层,证明冈底斯古陆并不存在,因此三陆两槽的基础地质认识也不成立。基于新的地层学发现,笔者提出了两陆一盆基础地质认识,将青藏高原的古生代—中生代海相盆地命名为古格盆地,指出古格盆地的措勤断块具有形成大型油气区的地质背景,古格层系和保吉层系是措勤断块的两个油气勘探的有利层系,都是碳酸盐岩台地相沉积,这两个层系大部分保存在白垩系地层之下,保存条件好。燕山期晚期—喜山期的南北向构造挤压造成措勤断块全区发育复式背向斜,郎山组及以下的地层形成褶皱,褶皱的背斜核部是油气勘探的有利构造部位,这些背斜构造在后期东西向断层的掀斜作用下,形成鼻状构造。这些鼻状构造的高点位置就是油气勘探的靶点位置。青藏高原油气勘探重心应该从羌塘断块转向措勤断块,建议在措勤断块识别出的鼻状构造高点部位开展物探和钻探验证工作。     

非贯通节理岩体损伤变量计算方法研究

作为岩体组成部分的非贯通节理对岩体力学特性有着重要影响,然而几乎目前所有的岩体损伤变量计算方法都仅考虑节理几何参数对岩体力学特性的影响。对含单组非贯通节理的岩体力学特性进行研究,提出一个能够同时考虑节理几何及强度参数对岩体力学特性影响的新的岩体损伤变量计算方法。首先,采用弹性余能等效假设代替Lemaitre应变等效假设研究由节理引起的岩体各向异性损伤,并基于断裂力学中单个节理引起的附加应变能增量与损伤力学应变能释放量相关联的观点,推导出由单条节理引起的损伤变量计算公式。其次,根据断裂力学理论获得了单轴压缩下单条节理尖端应力强度因子（SIF）KⅠ、KⅡ的计算公式。最后,通过考虑节理间的相互作用给出了单组单排或多排节理尖端应力强度因子KⅠ、KⅡ的计算公式,得到了单组节理引起的岩体损伤变量计算公式,并与已有试验结果的对比分析证明了该公式的合理性。     

现代人起源的多地区进化学说在中国的实证

关于现代人起源主要有两种学说:多地区进化说和近期出自非洲说。文章介绍了中国人类进化的假说:'连续进化附带杂交’。构成这个假说的基础的中国资料为多地区进化说提供实证。其直接证据来自人类化石,包括中国人类化石具有一系列共同特征,直立人与智人之间有形态学上的镶嵌,中国化石中有表现西方基因的形态学证据。另外,本文还简略介绍了用DNA研究中国现代人起源目前达到的结论,并从体质人类学、旧石器时代考古学、古环境研究和分子生物学研究等诸方面的资料对这个结论进行检验。     

优势种密度制约及其对森林群落物种多样性维持的影响（英文）

本研究以南亚热带优势树种黄果厚壳桂(Cryptocarya concinna)为研究对象,采用控制实验与样地调查相结合的方法,验证密度制约对群落物种多样性维持的影响。通过在黄果厚壳桂母树周围建立24个成对的1 m×1 m幼苗样方,定期进行幼苗群落调查并做土壤杀菌,分析杀菌处理对黄果厚壳桂幼苗存活率及其幼苗物种丰富度的影响。并通过样地调查进行不同龄级相对多度与群落均匀度的相关分析。结果表明,杀菌处理可显著降低幼苗群落物种丰富度。黄果厚壳桂幼树密度随着离母树距离的增加而增加,其种群占整个群落的相对多度随着树龄呈递减趋势,黄果厚壳桂种群优势地位的减少将直接导致群落均匀度的增加,从而避免单优种群的发生,促进多物种共存。。     

高速影像中风沙颗粒灰度和表观粒径的变化特征及对多假设追踪算法的意义

沙粒轨迹形成过程是理解风沙两相流输运力学机制的关键问题。多假设追踪算法通过融合追踪目标的多个信息特征和建立后验概率控制的动态递归算法来实现对目标的准确追踪,其精度可能优于传统的基于位置信息的轨迹追踪算法。基于多假设追踪算法的需要,以沙粒灰度和表观粒径(沙粒在影像上显现的大小)为对象,通过分析沙粒在轨迹形成过程中灰度和表观粒径的辨识度及稳定性来揭示它们作为多假设轨迹算法的特征参数的可能性和可靠性。结果表明:沙粒灰阶25~255,具有多峰分布的特征,表明不同沙粒灰度具有很好的区分度;80%~85%的沙粒在入射、反弹过程及粒-床碰撞后,灰度差在1倍标准偏差之内,表明大多数沙粒的灰度具有相对的稳定性;沙粒的表观粒径分布于77~1 001μm,表明表观粒径具有较好的区分度;97%~100%的沙粒在入射、反弹过程中、77%的沙粒在粒-床碰撞后,表观粒径差均是稳定的(77~154μm);仅有15%~23%的沙粒发生了显著的侧向运动或自旋,表明多数沙粒的灰度和表观粒径的稳定性不受侧向运动或自旋的影响;灰度和表观粒径可以作为多假设追踪算法的重要辨识参数。     

A global analysis of urbanization effects on amphibian richness: Patterns and drivers

Urbanization presents an unplanned and highly replicated global experiment to understand biotic responses to global changes. Here we conducted a global analysis on patterns and drivers of urbanization effects on biodiversity using the global amphibian richness dataset along with background climate and the continuous rural-urban gradients. We, for the first time, empirically generalized the urbanizational gradients of amphibian richness at the global scale and in different climate zones despite the substantial differences in history, ecological context, and socioeconomic conditions across large geospatial extents. We found a positive imprint of urbanization on amphibian richness in cool and climate zones whereas the presence of urban thermal stress in high temperature climate zones. Anthropogenic forces behind the urbanization gradients entangled with environmental variables directly and indirectly drove the patterns as revealed by the structural equation modeling (SEM). The urbanizational diversity gradient (UDG) found in this study might signify the existence of another general principle in ecology analogous to well-known latitudinal and elevational diversity gradients. We proposed the heat-and-threat balance (HATB) hypothesis to explain UDG: urbanization-induced heat would promote biodiversity if the ambient temperatures are cooler than their optima. Alternatively, it may put threats on biodiversity when the ambient temperatures are close to their optima. There is an urgent need to advance the knowledge on UDG in an urbanizing planet by additional studies from diverse taxa, various geographical locations, and at different scales.     

蛋白质感染因子与水产养殖

介绍了蛋白质感染因子的概念、蛋白质感染因子复制机理假说及其证明、蛋白质感染因子多样性等内容，并讨论了水产养殖动物中存在蛋白质感染因子疾病的可能性。     

From Objective Environmental Problems to Subjective Environmental Concern: A Multilevel Analysis Using 30 Indicators of Environmental Quality

This article analyzes the effect of environmental degradation, the affluence hypothesis, and postmaterialist theory to assess the environmental concern of individuals in 51 countries. The hypotheses are tested using a multilevel analysis that employs an unprecedented number of objective indicators of environmental degradation, using the World Values Survey 6th wave (2010–2014). The results support the degradation hypotheses, where the importance of water scarcity in a country and national biodiversity are the major variables that explain individual environmental concern among all the indicators of environmental degradation. The affluence hypothesis is rejected and the postmaterialist theory is supported only at the individual level.