煤巷复合顶板结构对其稳定性影响试验

煤层巷道复合顶板结构较为复杂,其自身稳定性与岩性、岩层厚度、层数、岩层位置及层间黏结力等因素有关。基于简化的复合顶板组合梁结构力学理论,建立了简化的组合梁力学测试模型,通过不同试验分析复合顶板结构特征对其稳定性的影响,其目的是为复合顶板稳定性分类及控制提供科学依据。研究结果表明：煤巷复合顶板厚度不变时,其自身稳定性随岩层强度提高、硬岩层厚度增加、硬厚岩层到煤层距离的减小及层间黏结力的增大而提高,随分层数的增多而降低,当层数达到4层及以上时,顶板稳定性受其层数变化的影响变小。各因素的影响程度由大到小依次：岩性 > 岩层厚度 > 层数 > 岩层位置 > 层间黏结力;强度低、厚度小的软弱薄夹层较其他岩层更易产生应力集中,且破坏早于其他岩层。     

温度对棉花产量结构及发育速度的可能影响

该文利用新疆农业气象观测资料，在构建棉花品种熟性指数的基础上，建立了温度对不同品种棉花产量结构及发育速度影响的模式，进一步分析了温度变化对不同品种棉花单株铃数、单铃重、霜前花比例及发育速度的可能影响。该文对棉花生产气象监测、预测及评价工作有重要参考价值。     

Water partitioning between mantle minerals from peridotite xenoliths

The speciation and amount of water dissolved in nominally anhydrous silicates comprising eight different mantle xenoliths has been quantified using synchrotron micro-FTIR spectroscopy. Samples studied are from six geographic localities and represent a cross-section of the major upper mantle lithologies from a variety of tectonic settings. Clinopyroxene contains between 342 and 413 ppm H₂O. Orthopyroxene, olivine and garnet contain 169–201, 3–54 and 0 to <3 ppm H₂O, respectively. Pyroxenes water contents and the distribution of water between ortho- and clinopyroxene is identical regardless of sample mineralogy (D _water^cpx/opx = 2.1 ± 0.1). The total water contents of each xenolith are remarkably similar (113 ± 14 ppm H₂O). High-resolution spectroscopic traverses show that the concentration and speciation of hydrous defects dissolved in each phase are spatially homogeneous within individual crystals and identical in different crystals interspersed throughout the xenolith. These results suggest that the amount of water dissolved in the silicate phases is in partial equilibrium with the transporting melt. Other features indicate that xenoliths have also preserved OH signatures of equilibrium with the mantle source region: Hydroxyl stretching modes in clinopyroxene show that garnet lherzolites re-equilibrated under more reducing conditions than spinel lherzolites. The distribution of water between pyroxenes and olivine differs according to xenolith mineralogy. The distribution of water between clinopyroxene and olivine from garnet peridotites (D _water^cpx/oliv(gnt) = 22.2 ± 24.1) is a factor of four greater than mineral pairs from spinel-bearing xenoliths (D _water^cpx/oliv(sp) = 88.1 ± 47.8). Such an increase in olivine water contents at the spinel to garnet transition is likely a global phenomenon and this discontinuity could lead to a reduction of the upper mantle viscosity by 0.2–0.7 log units and a reduction of its electrical resistivity by a factor of 0.5–0.8 log units.     

Holocene development of the River Lippe valley,Germany: a case study of anthropogenic influence

The characteristics of the Holocene valley floor of the River Lippe, Germany, are atypical for a river in central Europe. The valley floor consists of three terrace levels, which are not always clearly separated from each other. Analysis of the sediments making up the terraces indicates that they accumulated during the course of the entire Holocene, although there is insufficient information available to allow detailed determination of phases of fluvial change and stability responsible for terrace formation. Two of the terraces exist only in the lower reaches of the valley, where they converge and diverge with the third. The lowest terrace consists only of a narrow strip, running parallel to the river channel. The configuration of the valley floor may be explained by a series of anthropogenic influences. The earliest human impact probably occurred about 2000 years ago when, during their campaign against German tribes, the Romans built a towpath and may have changed the channel planform from its natural, anabranching pattern to a meandering form by building small dams on local distributary forks. Implementation of artificial meander cut‐offs to improve navigation on the river began in medieval times. The morphological response to these human interventions was primarily degradational. In the 19th century, artificial lateral fill was used to narrow the channel and the towpath was renewed several times. The trace of the most recent towpath is still discernible as a narrow strip parallel to the river channel, and it constitutes the lowest terrace level. Comparison between the bankfull discharge of a 4000‐year‐old abandoned channel and the formative flow for the modern channel supports the premise that, prior to anthropomorphic influence, the natural planform was anabranched. Copyright © 2000 John Wiley & Sons, Ltd.     

罗厝山井田构造特征及其对煤层厚度的影响

通过收集以往地质勘探和井下调查资料，总结了罗厝山井田的构造特征，探讨了井田构造对煤层厚度变化的影响，以期对煤炭生产及资源勘查有一定的指导作用。     

沁水盆地新近纪张村组油页岩评价及古环境分析

为了深入分析油页岩发育特征对古环境的指示作用,为油页岩资源评价提供理论指导,选取沁水盆地中部新近系张村组油页岩为研究对象,采用岩石热解、有机碳测定、X射线荧光光谱仪（XRF）测试等方法分析油页岩有机地球学和元素地球化学特征,探讨沉积期的古气候和古地理环境。结果表明,张村组油页岩含油率较低,为4.15%;干酪根类型为标准腐泥型（I₁）,埋藏较浅,生烃潜力较高;样品的微量元素富集指数和地球化学参数特征显示,张村组油页岩有机质为混合来源,湖泊自身生产力提供主要物质基础;沉积期气候温暖湿润,盆地内水体由盐湖逐渐淡化,油页岩形成于水体分层不强的厌氧、深湖环境。油页岩的地球化学特征与沉积期的古气候、古地理环境具有较好耦合性。     

煤矿采空区影响程度的两种评估方法对比分析

基于两种典型的采煤区影响程度评估方法,对比分析两种评估方法的结果,讨论二者的优缺点。研究结果表明：概率积分法和模糊综合评判法的采煤区影响程度划分结果存在明显差异。与模糊综合评判法相比,概率积分法的评价结果更为客观,理论体系更加成熟,但是其参数选取也存在的不足,建议根据参数反演选取预测参数。模糊综合评判法运用于采煤区影响程度分析存在缺陷,因子权重分配和影响程度隶属函数体系有待进一步完善。     

Laboratory investigation on wave transmission through two rows of perforated hollow piles

Experimental investigations on perforated hollow piles in two rows were conducted in a two dimensional wave flume. The influence of water depth, incident wave steepness, clear spacing between the piles and the spacing of pile rows on transmission coefficient have been studied. The effect of staggering of piles in rows is investigated. The results are also compared with the results of experiments on piles without perforations. The investigations have revealed that perforated piles attenuate more wave energy than non-perforated piles. The transmission coefficient K_t decreases as the wave steepness increases for both non-perforated and perforated piles. For non-perforated piles as relative clear spacing between the piles (b/D) decreases, for waves of higher steepness, K_t decreases while for perforated piles as b/D decreases, K_t is decreasing for all the steepness considered. As the relative clear spacing between the pile rows (B/D) increases K_t initially decreases till B/D is around one and later it starts increasing for both non-perforated and perforated piles. Staggering of piles has little effect on K_t. It is also found that water depth has insignificant influence on transmission coefficient at higher steepness for both perforated and non-perforated piles. Wave period alone does not directly influence transmission coefficient K_t.     

A Semi-Analytical Method for the PDFs of A Ship Rolling in Random Oblique Waves

The PDFs (probability density functions) and probability of a ship rolling under the random parametric and forced excitations were studied by a semi-analytical method. The rolling motion equation of the ship in random oblique waves was established. The righting arm obtained by the numerical simulation was approximately fitted by an analytical function. The irregular waves were decomposed into two Gauss stationary random processes, and the CARMA (2, 1) model was used to fit the spectral density function of parametric and forced excitations. The stochastic energy envelope averaging method was used to solve the PDFs and the probability. The validity of the semi-analytical method was verified by the Monte Carlo method. The C11 ship was taken as an example, and the influences of the system parameters on the PDFs and probability were analyzed. The results show that the probability of ship rolling is affected by the characteristic wave height, wave length, and the heading angle. In order to provide proper advice for the ship''s manoeuvring, the parametric excitations should be considered appropriately when the ship navigates in the oblique seas.