湖南省辰溪县石马湾区段找煤前景浅析

根据石马湾区段所处的区域构造位置,结合岩相古地理及聚煤规律的演化,运用成矿地质理论和方法,对区域内大面积出露的中侏罗统泸阳组地层下隐伏含煤岩系的含煤可能性进行了探讨,预测了区段内江口煤系资源预测量可达5 600万t,对下一步普查找煤工作具有一定的指导意义.     

Modes of Occurrence and Geological Origin of Beryllium in Coals from the Pu''''an Coalfield, Guizhou, Southwest China

The concentration, modes of occurrence and geological origin of beryllium in five workable coal beds from the Pu'an Coalfield of Guizhou were studied using the inductively coupled-plasma mass spectrometry (ICP-MS), floating and sinking experiments (FSE) and sequential chemical extraction procedures (SCEP). The results show that the average concentration of beryllium in coals from the Pu'an Coalfield is 1.54μg/g, much lower than that in most Chinese and worldwide coals. Beryllium in the Pu'an coals was not significantly enriched. However, it should be noted that the No. 8 coal bed from the study area has a high concentration of beryllium, 6.89μg/g, three times higher than the background value of beryllium in coal. Beryllium in coal mainly occurs as organic association and has predominantly originated from coal-forming plants when its concentration is relatively low. The concentration of beryllium occurring as organic association is close to that distributed in inorganic matter when beryllium concentration of coal is similar to its background value, and in addition to coal-forming plants, beryllium is mainly derived from detrital materials of terrigenous origin. When beryllium is anomalously enriched in coal, it mainly occurs as organic association and is derived from volcanic tonsteins leached for a long geological time and then adsorbed by organic matter in peat mire.     

基坑变形小波去噪及BP神经网络组合预测模型研究

以某市轨道交通1号线地铁站基坑观测数据为例,开展了小波及BP神经网络预测模型的研究。首先采用小波阈值去噪方式对纵向观测线实际观测数据进行去噪处理,依据信噪比最高以及均方根最小判别原则进行判别,实验表明,小波1层分解、软阈值方式、sym4小波基函数、rigrsure阈值原则、scal=sln为最佳组合方式。然后,给出基坑变形小波-BP神经网络组合预测模型。最后对小波去噪前后的数据进行BP神经网络预测模型预测处理并与小波变换神经网络预测模型预测数据进行对比分析,结果表明小波变换神经网络预测模型预测精度最高。     

Properties of Klebsiella phage P13 and associated exopolysaccharide depolymerase

The bacteriophage P13 that infects Klebsiella serotype K13 contains a heat-stable depolymerase capable of effective degradation of exopolysaccharide(EPS) produced by this microorganism. In this study, the titer of phage P13, initially 2.0 × 107 pfu mL-1, was found increasing 20 min after infection and reached 5.0 × 109 pfu mL-1 in 60 min. Accordingly, the enzyme activity of depolymerase approached the maximum 60 min after infection. Treatment at 70℃ for 30 min inactivated all the phage, but retained over 90% of the depolymerase activity. Addition of acetone into the crude phage lysate led to precipitation of the protein, with a marked increase in bacterial EPS degradation activity and a rapid drop in the titer of phage. After partial purification by acetone precipitation and ultrafiltration centrifugation, the enzyme was separated from the phage particles, showing two components with enzyme activity on Q-Sepharose Fast Flow. The soluble enzyme had an optimum degradation activity at 60℃ and pH 6.5. Transmission electron microscopy demonstrated that the phage P13 particles were spherical with a diameter of 50 nm and a short stumpy tail. It was a double-strand DNA virus consisting of a nucleic acid molecule of 45976 bp. This work provides an efficient purification operation including thermal treatment and ultrafiltration centrifugation, to dissociate depolymerase from phage particles. The characterization of phage P13 and associated EPS depolymerase is beneficial for further application of this enzyme.     

A physics-based dual-frequency approach for altimeter wind speed retrieval

The altimeter normalized radar cross section(NRCS) has been used to retrieve the sea surface wind speed for decades, and more than a dozen of wind speed retrieval algorithms have been proposed. Despite the continuing efforts to improve the wind speed measurements, a bias dependence on wave state persists in all wind algorithms. On the basis of recent evidence that short waves are essentially modulated by local winds and much less affected by wave state, we proposed a physics-based approach to retrieve the wind speed from the dual-frequency difference in terms of the mean square slope of short waves. A collocated dataset of coincident altimeter/buoy measurements were used to develop and validate the approach. Validation against buoy measurements indicates that the approach is almost unbiased and has an overall root mean square error of 1.24 m s-1, which is 5.3% lower than the single-parameter algorithm in operational use(Witter and Chelton, 1991) and 2.4% lower than another dual-frequency approach(Chen et al., 2002). Furthermore, the results indicate that the new approach significantly improves the wave-dependent bias compared to the single-parameter algorithm. The capacity of altimeter to retrieve sea surface wind speed appears to be limited for the case of winds below 3 m s-1. The validity of the approach at high winds needs to be further examined in the future study.     

Mineralogy and geochemistry of Al-hydroxide/oxyhydroxide mineral-bearing coals of Late Paleozoic age from the Weibei coalfield, southeastern Ordos Basin, North China

This paper mainly describes mineralogy and geochemistry of coals from the Weibei coalfield in the southeastern Ordos Basin, North China. A number of Al-hydroxide/oxyhydroxide minerals were detected in the Late Carboniferous coals (Nos. 5, 10 and 11 coals), especially in the No. 10 coal. Aluminum-hydroxide/oxyhydroxide minerals (nordstrandite, boehmite and diaspore) in the No. 10 coal are associated with kaolinite, suggesting that these minerals are derived from the breakdown of kaolinite. A model in which Al-hydroxide/oxyhydroxide minerals form from the incongruent dissolution of kaolinite is presented. Nordstrandite and boehmite mainly occur as massive lenses (<500 μm in length). Diaspore appears as massive aggregates and as single euhedral crystals (<50 μm in length) in a kaolinite matrix. The presence of high temperature quartz, and zircon indicates that there was input of felsic volcanic debris during accumulation of the Late Carboniferous coals. These volcanic materials have also had a significant influence on the enrichment of certain trace elements including Li, Be, Ga, Zr, Nb, Mo, Sn, W and U in the Late Carboniferous coals (Nos. 5, 10, and 11 coals). SEM-EDX results show that Ga in the No. 10 coal (whole coal average 33.4 μg/g; n = 2) mainly occurs within Al-hydroxide/oxyhydroxide minerals (nordstrandite, boehmite, and diaspore), kaolinite and organic matter.     

巴楚地区断裂带内热液流体活动及对碳酸盐岩改造的特征分析

以塔里木盆地巴楚隆起区良里塔格组露头剖面为例,应用薄片观察和阴极发光等岩石学分析方法以及碳氧同位素、87Sr/86Sr比值、常量元素和流体包裹体测温等地球化学定量分析手段,综合分析了构造热液活动对碳酸盐岩的改造作用.研究结果显示,发育在碳酸盐岩内的断裂带及其附近,局部白云岩化特征显著;碳氧同位素表现异常,由断裂的两盘向...     

国际气候治理中的公正转型议题：概念辨析与治理进展

国际气候治理中的公正转型议题涉及就业、关乎民生,是各国都很关注的政策领域之一,因此也被视为是支持应对气候变化的一种重要社会机制。近年来,国际社会积极推动建设气候治理公正转型制度体系,各国也在所制定的国家应对气候变化战略和规划中越来越多地提出与公正转型和就业相关的目标与措施。公正转型议题在国际气候治理进程中主流化的趋势给中国参与和引领全球气候治理带来了新的机遇与挑战。中国应加强关于该问题的基础性研究;在国内应对气候变化的行动中充分考虑该问题,保障受影响就业群体获得社会公正对待;总结具体实践经验;在政策领域协调上做好新的布局;积极参与《联合国气候变化框架公约》下公正转型治理体系的构建中。     

3种经典机器学习算法在火山岩测井岩性识别中的对比

岩性识别一直是火山岩油气勘探中的重要课题,基于测井数据的岩性识别也逐渐成为火山岩研究的需要,大数据背景下的机器学习算法为测井岩性识别提供了一个新方向。为提高某研究区火山岩岩性识别符合率,本文采用K近邻、支持向量机和自适应增强3种经典机器学习算法,对研究区内的粗面岩、非致密粗面岩、辉绿岩、辉长岩、玄武岩和非致密玄武岩等6类中基性火山岩进行岩性识别。从常规测井系列中优选对研究区岩性敏感的自然伽马、声波时差、补偿中子、深侧向电阻率和补偿密度等5种测井参数作为岩性识别模型的输入向量,从研究区内5口有岩心样品或薄片鉴定资料的目标层中选取测井数据点1 440个,其中960个作为训练样本,其余480个作为测试样本。以识别符合率和时间作为评价指标,对3种算法的识别结果进行对比分析,实验表明：自适应增强算法的分类准确率最高,6类岩性平均识别符合率达到82.10%;支持向量机算法表现良好,平均识别符合率为81.04%;K近邻算法平均识别符合率为76.04%。