塔吉克斯坦阿尔登-托普坎铅锌矿床地质特征及控矿因素分析

阿尔登–托普坎铅锌矿床（简称阿矿）,位于塔吉克斯坦第二大城市胡占德（苦盏）北东方向110 km处,是阿尔登–托普坎矿田主要矿床之一。该矿田勘查与开发历史悠久,是塔吉克斯坦境内最重要的铅锌矿集区,矿田内分布大小不等的十二个铅锌矿床,其中主要的矿床为三个,即派布拉克矿床、阿尔登–托普坎矿床及北阿尔登–托普坎矿床,三个主要矿床相距2 km以内（周叶,2010）。本文论述阿尔登–托普坎矿床的区域地质背景和主要成矿特征,分析其主要控矿因素,并对其成因类型进行归属研究,为塔吉克境内相同类型铅锌矿床的找矿勘查工作提供依据。     

煤层气储层伤害机理与水平井双层管柱筛管完井技术

煤储层具有高吸附性、低渗透性、易压缩与易破碎的特征,煤层气水平井钻完井过程中常常造成煤储层伤害,导致煤层渗透率和单井煤层气产量大幅度降低。通过实验分析,揭示水平井钻完井液中的固相颗粒、流体流动诱导产生的固相成分对煤储层微裂隙堵塞成因,阐明煤层气水平井钻完井中储层伤害的机理。在此基础上,提出水平井双层管柱筛管完井技术,分析其减轻煤储层伤害的机理,即通过冲管水力冲击作用消除水平井壁钻井液泥饼,清除井壁附近堵塞微裂隙煤粉,并在近井地带产生应力增渗作用。相对于煤层气常规的多分支水平井及分段压裂水平井,水平井双层管柱筛管完井的稳定日产气量、稳产周期均大幅提升。该技术在沁水盆地南部部分区域推广应用显示,3号煤层气井平均日产气量提升到20 000 m3,同时实现15号煤层气的开发突破,平均日产气量提升到10 000 m3以上。研究成果对于降低煤层气水平井钻完井过程中的储层伤害,提高煤层气井产量具有重要的理论和实践意义。      

TanDEM-X multiparametric data features in sea ice classification over the Baltic sea

In this study, we assess the potential of X-band Interferometric Synthetic Aperture Radar imagery for automated classification of sea ice over the Baltic Sea. A bistatic SAR scene acquired by the TanDEM-X mission over the Bothnian Bay in March of 2012 was used in the analysis. Backscatter intensity, interferometric coherence magnitude, and interferometric phase have been used as informative features in several classification experiments. Various combinations of classification features were evaluated using Maximum likelihood (ML), Random Forests (RF) and Support Vector Machine (SVM) classifiers to achieve the best possible discrimination between open water and several sea ice types (undeformed ice, ridged ice, moderately deformed ice, brash ice, thick level ice, and new ice). Adding interferometric phase and coherence-magnitude to backscatter-intensity resulted in improved overall classification per- formance compared to using only backscatter-intensity. The RF algorithm appeared to be slightly superior to SVM and ML due to higher overall accuracies, however, at the expense of somewhat longer processing time. The best overall accuracy (OA) for three methodologies were achieved using combination of all tested features were 71.56, 72.93, and 72.91％ for ML, RF and SVM classifiers, respectively. Compared to OAs of 62.28, 66.51, and 63.05％ using only backscatter intensity, this indicates strong benefit of SAR interferometry in discriminating different types of sea ice. In contrast to several earlier studies, we were particularly able to successfully discriminate open water and new ice classes.     

海冰盐度影响下冰水热力过程的试验研究

北极多年海冰的渡夏与冰脊形成的初始阶段均属于海冰升温的热力学过程。在卤水作用下,海冰在升温过程中需要融化内部的固态冰以达到温盐平衡。为研究海冰升温过程中盐度对宏观热力学性质的影响,本文设计了冰块试样在水中的一维浸没试验。将具有相同初始温度 （-32℃）、不同盐度 （0 ppt, 2.65 ppt, 12 ppt） 的冰试样浸至 0.2 ℃的淡水环境中,并测试试样内部温度场与厚度变化。试验结果表明,高盐度海冰的最终冰厚增加量超过 31%,而淡水冰则仅为 15%。海冰内部卤水的活跃改变了海冰的宏观比热并大幅度提高了其潜在的内能变化量。同时,将内能变化的实测结果与 Schwerdfeger 模型理论计算结果进行了对比。分析得出,真实环境中在海冰卤水迁移引起的盐度不均匀分布与卤水外排使得 Schwerdfeger 模型无法准确描述海冰升温过程中热力学性质。此外,通过对新生冰进行冰晶测试中所观测的柱状结构及晶粒尺寸特征也进一步验证了试验结果的可靠性。     

Does wetland watershed land use influence amphibian larval development? A relevant effect of agriculture on biota

Agriculture practices have been widely proposed as the major cause of amphibian population decline. However, the majority of these results have been based on laboratory experiments. The present study was conducted to test the repercussion of wetland sediment provenance on amphibian larval development.Bufo bufo larvae were used in two dif ferent treatments in an outdoor experiment, the ?rst one using sediment from one wetland surrounded by intensive agricultural practices, and the second using sediment with no record of agrochemical uses. A negative ef fect was observed in the agricultural treatment, from subcellular to individual level. The results showed that the sediment from agricultural practices watershed generates a reduction in survival. Furthermore, individuals that developed under this treatment showed a lower total length and a delay in the time necessary to complete metamorphosis; these features are connected with recruitment success. In the same way, biochemical analysis showed high values of lipid peroxidation in metamorphs developing in sediments from an agricultural area. Finally, the results obtained highlight the importance of considering the sediments, not only the water, as origin treatment, allowing us to understand the consequences on amphibian populations that inhabit areas af fected by intensive agriculture.     

塔里木河下游生态输水条件下胡杨林生态系统恢复研究

基于文献阅读,对塔里木河下游生态输水条件下胡杨林生态系统的恢复响应进行了讨论分析.生态输水显著抬升了地下水位,降低了地下水矿化度与土壤干旱指数,有效改善了塔里木河下游胡杨林生态系统的生境;胡杨复壮明显,距河道50 m胡杨冠幅最大增长达511.20％,距河道500 m内胡杨枯枝比平均小于0.15.输水后,下游胡杨树干径向...     

Background and Research Prospect of Geo-ecological Survey and Monitor in the Critical Zone of Black Soil

正The American Science journal,on the occasion of its 125 publication anniversary,in 2016,released 125 of the most challenging scientific issues (Kennedy et al.,2005) to the world.According to the basics,breadth and the influence,25 of the issues which considered to be the most important were screened,including"How many people can the Earth carry?"(Stokstad,2005;Dailyg et al.,1992;Cohen,1995) and"How high will the greenhouse effect make the earth temperature?"These two     

Development of periglacial landforms and soil formation in the Ilgaz Mountains and effect of climate(Western Black Sea Region-Türkiye)

The main aims of the current study are to determine the morphological features of the periglacial landforms(non-sorted step, mud circle, stony earth circle, thufur, and congeliturbation) located on the Ilgaz Mountains, examine the physicochemical and mineralogical properties with pedological processes of the soils, and assess of the effects of climatic conditions controlling the development of landforms. The Ilgaz Mountains(2587 m a.s.l.), located in the Western Black Sea Region, within the Anat...     

Direct use of peak ground motion parameters for the estimation of inelastic displacement ratio of SDOF systems subjected to repeated far fault ground motions

This study is aimed at developing statistical equations to estimate the inelastic displacement ratio of singledegree- of-freedom systems subjected to far fault repeated earthquakes. In the study, peak ground motion parameters are used to define the scatter of the original data. The ratio of peak ground acceleration to peak ground velocity, and peak ground velocity of the ground motion records and structural parameters such as period of vibration and lateral strength ratio are used in the proposed equations. For the development of the equations, nonlinear time history analyses of single-degree-offreedom systems are conducted. Then, the results are used in a multivariate regression procedure. The equations are verified by comparing the estimated results with the calculated results. The average error and coefficient of variation of the proposed equations are presented. The analyses results revealed that the direct use of peak ground motion parameters for the estimation of inelastic displacement ratio significantly reduced the scatter in the original data and yielded accurate results. From the comparative results it is also observed that results obtained using equations specific to peak ground velocity or peak ground acceleration to peak ground velocity ratio are similar.