南秦岭勉县─略阳结合带蛇绿岩与岛弧火山岩地球化学及其大地构造意义

南秦岭勉县-略阳结合带中超基性岩类主要为方辉橄榄岩和纯橄榄岩,稀土特征为轻稀土亏损,铕富集型;辉绿岩均为轻稀土富集型。变质火山岩可区分为两种组合：一为轻稀土亏损的洋脊拉斑玄武岩,其Ti／V．Th／Ta、Th／Yb、Ta／Yb表明其为MORB型玄武岩,代表本区消失了的洋壳岩石,指示本区晚古生代一早中生代期间的一个古洋盆。另一类为岛弧火山岩组合,除岛弧拉斑玄武岩外,甚至还有大量中、酸性岛弧火山岩,它们并非洋壳的物质组成,而是大陆弧岩浆活动的产物。这表明勉略洋盆在晚古生代-早中生代期间曾经经历过一个较完整的有限洋盆的发生、发展与消亡过程,这期间秦岭已成为一独立的岩石圈微板块,其南缘具有活动大陆边缘的构造属性,秦岭并非华北与扬子陆块之间的简单碰撞产物。     

利用变参数回归方法反演泥质岩裂缝密度

本文利用变参数回归分析建立了多口井的泥质岩储层裂缝密度模型。该模型的平均相对误差为１３．５％,较常系数回归分析、ＢＰ网络模型进行裂缝预测的精度高（平均相对误差分别为３８．７％、１７．９％）。通过实际资料处理认为该油田在纵向上随时代变老,深度加深,裂缝密度降低。即从Ｎ２２、Ｎ１２到Ｎ１,平均裂缝密度从０．７８条／ｍ、０．５条／ｍ降低到０．３条／ｍ。在平面上,沿构造轴部裂缝最发育,平均裂缝密度Ｎ２２、Ｎ１２、Ｎ１层分别为０．５８条／ｍ、０．６条／ｍ、０．３条／ｍ。     

Geochemical Features and Tectonic Settings of Upper Ordovician Marine Volcanic Rocks on North Margin of Qaidam

ＩＮＴＲＯＤＵＣＴＩＯＮＡＮＤＢＲＩＥＦＧＥＯＬＯＧＩＣＡＬＤＥＳＣＲＩＰ┐ＴＩＯＮＳＴｈｅＵｐｐｅｒＯｒｄｏｖｉｃｉａｎｍａｒｉｎｅｖｏｌｃａｎｉｃｒｏｃｋｓｏｎｔｈｅｎｏｒｔｈｍａｒｇｉｎｏｆＱａｉｄａｍｈａｖｅｂｅｅｎｒｅｐｅａｔｅｄｌｙｄｉｓ...     

深圳市闪电定位资料误差分析及其优化

利用场地误差优化模式对深圳地区的地闪定位资料进行优化处理。首先对深圳市闪电定位系统进行简单介绍,然后利用改进的传输线模式对真实地表环境下的闪电辐射电磁场进行计算,以分析深圳市闪电定位系统的场地误差,最后基于定位误差和场地误差模式对闪电定位数据进行定位误差订正。结果表明不同方位角上的不规则地形对继后回击电磁场波形具有不同影响,随着表征地形粗糙程度的高度均方根的增加,电场的峰值下降,波形的上升沿时间增加。同时,电场波形上升沿时间也会随着方位角的变化而变化,这可能会给时间到达法的定位带来一定误差。为了验证该算法的合理性,对该系统覆盖的区域进行了闪电定位数据优化精度的时空分布分析和评估。结果表明这种优化方案是可行的、可靠的,优化后的闪电定位精度明显提高。     

柳州夏季一次雨夹冰雹的天气过程分析

利用常规地面观测、柳州地面自动站、FY-2C卫星、柳州和河池的多普勒天气雷达观测资料,对2014年7月22日夏季柳州发生的一次短暂的雨夹冰雹天气过程的环境条件和雷达产品特征进行分析,主要结果如下:受副高和台风外围气流影响,柳州全市出现了37℃以上大范围的高温天气,天气尺度和中尺度的上升运动较弱,局地性质的加热作用导致大气的不稳定度加强而诱发对流云系进一步发展造成的;雷达显示的冰雹云的最大基本反射率因子为65d BZ,强回波区面积小;风速的切变和辐合上升运动小,0℃层高度较高,不利于对流系统的发展和维持。     

Characteristics of convection and overshooting in RGB and AGB stars

Based on the turbulent convection model (TCM) of Li & Yang, we have studied the characteristics of turbulent convection in the envelopes of 2 and 5M⊙ stars at the red giant branch and asymptotic giant branch phases. The TCM has been successfully applied over the entire convective envelopes, including the convective unstable zone and the overshooting regions. We find that the convective motions become progressively stronger when the stellar models are located farther up along the Hayashi line. In the convect...     

A note on the discovery of a 2M_⊙ pulsar

It is conventionally thought that the state equation of dense matter softens and thus cannot result in high maximum mass if pulsars are quark stars and that a recently discovered 2M⊙ pulsar (PSR J1614-2230) may make pulsars unlikely to be quark stars. However, this standard point of view would be revisited and updated if quark clustering could occur in cold quark matter because of the strong coupling be- tween quarks at realistic baryon densities in compact stars. It can be argued that the state equation of...     

Origin and evolution of oilfield brines from Tertiary strata in western Qaidam Basin: Constraints from <Superscript>87</Superscript>Sr/<Superscript>86</Superscript>Sr, δD, δ<Superscript>18</Superscript>O, δ<Superscript>34</Superscript>S and water chemistry

Chemistry of major and minor elements, ⁸⁷Sr/⁸⁶Sr, δD, δ¹⁸O and δ³⁴S of brines were measured from Tertiary strata and Quaternary salt lakes in the western Qaidam Basin. The water chemistry data show that all oilfield brines are CaCl₂ type. They were enriched in Ca²⁺, B³⁺, Li⁺, Sr²⁺, Br⁻, and were depleted in Mg²⁺, SO₄ ²⁻, which indicated that these brines had the characteristics of deeply circulated water. The relationship between δD and δ¹⁸O shows that all data of these brines decline towards the Global Meteoric Water Line (GWL) and Qaidam Meteoric Water Line (QWL), and that the intersection between oilfield brines and Meteoric Water Lines was close to the local spring and fresh water in the piedmont in the western Qaidam Basin. The results suggest that oilfield brines has initially originated from meteoric water, and then might be affected by water-rock metamorphose, because most oilfield brines distribute in the range of metamorphosing water. The ⁸⁷Sr/⁸⁶Sr values of most oilfield brines range from 0.71121 to 0.71194, and was less than that in salt lake water (>0.712), but close to that of halite in the study area. These imply that salt dissolution occurred in the process of migration. In addition, all oilfield brines have obviously much positive δ³⁴S values (ranging from 26.46‰ to 54.57‰) than that of salt lake brines, which was caused by bacterial sulfate reduction resulting in positive shift of δ³⁴S value and depleteed SO₄ ²⁻ in oilfield brines. Combined with water chemical data and δD, δ¹⁸O, ⁸⁷Sr/⁸⁶Sr, δ³⁴S values, we concluded that oilfield brines mainly originate from the deeply circulated meteoric waters, and then are affected by salt dissolution, water-rock metamorphose, sulfate reduction and dolomitization during the process of migration. These processes alter the chemical compositions of oilfield brines and accumulate rich elements (such as B, Li, Sr, Br, K and so on) for sustainable utilization of salt lake resources in the Qaidam Basin.     

福建省矿山地质环境现状和防治建议

通过总结福建省矿山开采所造成的矿山地质环境主要问题,分析其对矿山及其周围地质环境造成影响并可能诱发的多种地质环境问题及其危害性。根据福建省矿山地质环境治理现状,提出进一步保护和防治矿山地质环境问题的有效措施。     

Semisupervised heterogeneous ensemble for ship target discrimination in synthetic aperture radar images

Ship detection using synthetic aperture radar (SAR) plays an important role in marine applications. The existing methods are capable of quickly obtaining many candidate targets, but numerous non-ship objects may be wrongly detected in complex backgrounds. These non-ship false alarms can be excluded by training discriminators, and the desired accuracy is obtained with enough verified samples. However, the reliable verification of targets in large-scene SAR images still inevitably requires manual interpretation, which is difficult and time consuming. To address this issue, a semisupervised heterogeneous ensemble ship target discrimination method based on a tri-training scheme is proposed to take advantage of the plentiful candidate targets. Specifically, various features commonly used in SAR image target discrimination are extracted, and several acknowledged classification models and their classic variants are investigated. Multiple discriminators are constructed by dividing these features into different groups and pairing them with each model. Then, the performance of all the discriminators is tested, and better discriminators are selected for implementing the semisupervised training process. These strategies enhance the diversity and reliability of the discriminators, and their heterogeneous ensemble makes more correct judgments on candidate targets, which facilitates further positive training. Experimental results demonstrate that the proposed method outperforms traditional tri-training.