伽玛射线暴源的新分布“BATSE的观测结果

介绍了康普顿γ射线天文台上ＢＡＴＳＥ有关暴源分布观测的新发展。这一发现对８０年代以前所普遍接受的γ射线暴起源于银盘内中子星的模型提出了严重挑战，并阐明了几种以ＢＡＳＥ结果基础的暴源分布模型。     

山东新生代火山岩分布与胃癌患病趋势

山东临朐是我国胃癌高发县之一，境内约一半面积属新生代火山岩区域。为研究新生代火山岩与胃癌相关关系，笔者进行了实地区域地质考察，同时进行胃癌流行病学调查。临朐２８个乡镇中１５个乡镇在新生代火山岩区域，其胃癌患病率最高为２７２．９１／１０万，平均为８８．７５／１０万；非新生代火山岩区域中１３个乡镇平均患病率为４６．８７／１０万，最低的嵩山乡胃癌患病率为２７．２２％／１０万。统计学计算表明新生代火岩区与非新生代火山岩区胃癌患病率有极其显著差异（Ｔ＝２．９６，Ｐ＜０．０１）。在临朐区域地质底图上绘制的胃癌患病率趋势图，以及以地质剖面图为横坐标，胃癌患病率为纵坐标的胃癌患病率与新生代火山岩相关关系图均表明：胃癌异常高患区与新生代火山岩地质体相吻合，愈靠近新生代火山岩中心区域胃癌患病率愈高。     

东秦岭地区浅隐花岗岩体遥感识别模式

在含金地层分布区，研究揭示隐伏岩浆热源活动特征及基底导岩导矿构造特征是寻找隐伏金矿床的技术关键。本文依据花岗岩体侵位动力学及热力学机制，阐明了线、环同现构造影像的形成机理及其所揭示的地质内涵，指出了环形影像构造成因的多解性，提出了如何从纷杂的“环、线”影像构造中提取出反映岩体侵位这一特定影像构造的原则及其重要性，以遥感技术为主导，综合应用地质、物化探技术，建立了“环状影像构造－斜磁化场－重力亏损场－岩浆期后热液活动中心的多元信息同现”隐伏成矿花岗岩体的遥感综合判读模式，实现了遥感解译由模糊—定性—定量化的综合解译判读过程。论证了东秦岭一些地区存在着规模宏大的燕山期浅隐伏成矿花岗岩体，并定量解译了隐伏花岗岩体的形态、产状及规模，指出金及其伴生元素的含矿热液活动受隐伏岩浆活动及基底导岩导矿构造双重因素控制     

湖泊(水库)沉积物分析在土壤侵蚀研究中的运用

土壤侵蚀研究对于防治自然灾害,实现土地的可持续利用具有重要的现实意义。由于一些地区长期以来水文观测资料较为匮乏,针对过去时间段内的土壤侵蚀研究通常需要寻找替代指标。湖泊(水库)作为流域内侵蚀产物的“汇”,其沉积物可不同程度地记录较长时期土壤侵蚀的具体特征,因此,基于湖泊(水库)沉积物分析的土壤侵蚀研究具有较强的应用价值和发展潜力。本文主要围绕确定土壤侵蚀年代,反演侵蚀过程,探寻沉积物来源的研究主线,详细论述了湖泊(水库)沉积物中放射性同位素、矿物磁性、粒度以及地球化学指标的应用原理和方法,分别总结了国内外学者利用湖泊(水库)沉积物在上述3个领域所取得的研究成果,在此基础上讨论了目前研究中存在的不确定性,并对未来的研究方向进行了展望。     

Optimal design and dynamic impact tests of removable bollards

Anti-ram bollard systems, which are installed around buildings and infrastructure, can prevent unauthorized vehicles from entering, maintain distance from vehicle-borne improvised explosive devices (VBIED) and reduce the corresponding damage. Compared with a fixed bollard system, a removable bollard system provides more flexibility as it can be removed when needed. This paper first proposes a new type of K4-rated removable anti-ram bollard system. To simulate the collision of a vehicle hitting the bollard system, a finite element model was then built and verified through comparison of numerical simulation results and existing experimental results. Based on the orthogonal design method, the factors influencing the safety and economy of this proposed system were examined and sorted according to their importance. An optimal design scheme was then produced. Finally, to validate the effectiveness of the proposed design scheme, four dynamic impact tests, including two front impact tests and two side impact tests, have been conducted according to BSI Specifications. The residual rotation angles of the specimen are smaller than 30º and satisfy the requirements of the BSI Specification.     

大兴安岭中段上二叠统林西组核形石的发现及其地质意义

林西组是大兴安岭地区晚二叠世重要的沉积地层,其研究程度也直接影响古亚洲洋闭合、两大板块拼接、沉积环境转变等重大地质问题。本次研究区主要位于大兴安岭中段,根据实际调查,首次在扎赉特旗巴彦乌兰地区晚二叠系林西组发现了海相的核形石灰岩。根据岩石学、地球化学和古生物学等研究手段,并根据元素比值等确定该核形石灰岩产生于碳酸盐台地边缘温暖、动荡的浅滩环境,具有明显的海相特征,并在林西组中—下部发现了具有明显陆相沉积特征的双壳类Palaeanodonta sp—Palaeomutela sp组合。说明该地区在晚二叠世早期存在海相或海陆交互相的沉积环境,随着环境的改变,林西组逐渐向陆地河湖相沉积环境转变。这一发现不仅完善了兴蒙地区林西组地层的结构,也为以后研究兴蒙海槽在晚古生代—中生代的过渡时期的沉积演化提供可靠资料。     

河南省陕县金矿找矿前景评价

崤山地区为陕县黄金主要产地,与其邻区小秦岭和熊耳山地区相比,金矿找矿、勘探、开发力度尚显不足。本文通过遥感地质综合解译,论证了崤山地区具有良好的金矿成矿地质条件,在此基础上采用“矿化有利度法”对崤山地区金矿成矿远景进行了综合信息定量预测,结果表明崤山地区具有良好的金矿找矿前景,需进一步加大找矿勘探力度。     

A New Growth Model of Fault Attributes in a Strike-Slip Fault System in the Tarim Basin

Fault attributes generally display a consistent power–law-scaling relationship. Based on new 3D seismic data, however, we found some exceptional fault attribute relationships of lengths (L)–throw (T) (vertical component of displacement), overlap zone length (Lo)–width (Wo) from a strike-slip fault system of the Ordovician carbonates in the Tarim Basin. The L–T relationship shows two linear segments with breakup at ~40 km in fault length. This presents an exceptional throw increase in the second stage, which is attributed to a localization of vertical displacement and deformation in overlapping zones other than the different fault scales in a mature fault zone. The Lo–Wo relationship in the overlapping zones shows multiply stepped-shape patterns, suggesting multiple fault differential growth and periodic increase in fault size. Therefore, we propose a new alternative growth model of fault attributes in strike-slip fault zones, in which the overlapping zones accumulated localized displacement and deformation in the intracratonic strike-slip fault zone.     

基于LightGBM的全球海洋次表层温盐遥感预测

随着卫星遥感技术的发展,越来越多的卫星观测数据被应用于预测海洋内部温盐结构信息,而如何有效提高海洋内部温盐信息的预测精度仍是一个挑战。本文应用LightGBM算法结合随机森林算法构建全球海洋次表层（0—1000 m）温度异常（STA）与盐度异常（SSA）的预测模型,模型使用海表卫星观测数据（海表高度异常（SSHA）、海表温度异常（SSTA）、海表盐度异常（SSSA）和海表风场异常水平和垂直分量（USSWA、VSSWA）,结合经纬度信息（LON、LAT）作为预测变量,使用Argo次表层温盐数据作为模型训练与测试标记。本文使用五参数模型（SSTA、SSHA、SSSA、USSWA、VSSWA）、带纬度六参数模型（LAT、SSTA、SSHA、SSSA、USSWA、VSSWA）、带经度六参数模型（LON、SSTA、SSHA、SSSA、USSWA、VSSWA）与带经纬度七参数模型（LON、LAT、SSTA、SSHA、SSSA、USSWA、VSSWA）来着重分析LON与LAT在STA、SSA遥感预测中发挥的作用。结果表明LON与LAT在STA、SSA各自预测中发挥不同的作用。在单时相和时序预测STA中LON与LAT对模型的贡献随着深度的增加逐渐增大,而在单时相和时序预测SSA中LON与LAT对不同深度预测模型始终保持较大的贡献。在单时相预测STA与SSA中LON较LAT对模型贡献更大,而在时序预测STA与SSA中LAT较LON对模型贡献更大。经纬度信息是全球海洋次表层温盐机器学习预测的重要参数,可以提高模型的预测精度。同时,LightGBM较随机森林在预测海洋次表层温盐异常时精度更高鲁棒性更强。     

Analytical solutions for the consolidation of unsaturated foundation with prefabricated vertical drain

Based on the consolidation theory raised by Fredlund, the solutions for the equal-strain consolidation of unsaturated foundation with the prefabricated vertical drain considering smear effect and drain resistance are analytically formulated in this paper. Firstly, governing equations for excess pore pressures (i.e., excess pore-air and pore-water pressures) under the equal-strain hypothesis are derived with the introduction of radial boundary conditions. Afterwards, the obtained coupled equations are solved by applying general integration, decoupling process, and Fourier sine series expansion. The smear coefficients and factors of drain resistance corresponding to air and water phases are both captured explicitly in the final solutions. Furthermore, the degenerated solutions are employed to verify the reliability of the current solutions. Finally, a parametric study is conducted to study the consolidation characteristics of the proposed foundation model against modeling sizes (S and N), smear coefficients (α_a and α_w), and drain resistance factors (G_a and G_w).