露井联采下边坡稳定性的相似模拟研究

露井联采模式下露井边界参数的合理选取,是决定露天边坡稳定的关键因素.通过相似模拟试验对安太堡露天矿南帮4#煤和9#煤露井联合开采下露天边坡的破坏过程进行了研究,分析了边坡破坏模式以及边坡的沉降变形规律.结果表明,露井联采下安太堡南帮边坡存在3种破坏模式:1435～1450平台的沉降破坏、1390～1435平台的沉降和滑移复合破坏,并最终转为滑移破坏、1280～1390平台的滑移破坏. 并指出在4#和9#煤复合开采产生的地表沉降中9#煤占总沉降量的60%以上.通过模拟得出,安太堡南帮实际边坡位置应整体后移20m,使井工开采工作面开切眼的位置由原1390台阶下移到1405台阶下,保证其开切眼所在位置至露天边坡台阶的垂直安全高度应在131m以上,该结论有效地解决了多年来困扰安太堡南帮露井联采边坡稳定性问题.     

Degradation induces changes in the soil C:N:P stoichiometry of alpine steppe on the Tibetan Plateau

Due to the Tibetan Plateau's unique high altitude and low temperature climate conditions,the region's alpine steppe ecosystem is highly fragile and is suffering from severe degradation under the stress of increasing population,overgrazing,and climate change.The soil stoichiometry,a crucial part of ecological stoichiometry,provides a fundamental approach for understanding ecosystem processes by examining the relative proportions and balance of the three elements.Understanding the impact of degradation on the soil stoichiometry is vital for conservation and management in the alpine steppe on the Tibetan Plateau.This study aims to examine the response of soil stoichiometry to degradation and explore the underlying biotic and abiotic mechanisms in the alpine steppe.We conducted a field survey in a sequent degraded alpine steppe with seven levels inNorthern Tibet.The plant species,aboveground biomass,and physical and chemical soil properties such as the moisture content,temperature,pH,compactness,total carbon(C),total nitrogen(N),and total phosphorus(P)were measured and recorded.The results showed that the contents of soil C/N,C/P,and N/P consistently decreased along intensifying degradation gradients.Using regression analysis and a structural equation model(SEM),we found that the C/N,C/P,and N/P ratios were positively affected by the soil compactness,soil moisture content and species richness of graminoids but negatively affected by soil pH and the proportion of aboveground biomass of forbs.The soil temperature had a negative effect on the C/N ratio but showed positive effect on the C/P and N/P ratios.The current study shows that degradation-induced changes in abiotic and biotic conditions such as soil warming and drying,which accelerated the soil organic carbon mineralization,as well as the increase in the proportion of forbs,whichwere difficult to decompose and input less organic carbon into soil,resulted in the decreases in soil C/N,C/P,and N/P contents to a great extent.Our results provide a sound basis for sustainable conservation and management of the alpine steppe.     

Tectonometamorphic Evolution of the Eastern Tibet Plateau: Evidence from the Central Songpan-Garze Orogenic Belt, Western China

The Songpan–Garzê Orogenic Belt (northeastern TibetPlateau) experienced polyphase deformation and metamorphismthat is best developed in the Danba Domal Metamorphic Terrane(DDMT), in which three tectonometamorphic events can be identified.The first event (D₁–M₁) is characterized by prograde sericite-to kyanite-grade Barrovian metamorphism during late Indosinian(     

Microbial diversity in Huguangyan Maar Lake of China revealed by high-throughput sequencing

Huguangyan Maar Lake is a typical maar lake in the southeast of China. It is well preserved and not disturbed by anthropogenic activities. In this study, microbial community structures in sediment and water samples from Huguangyan Maar Lake were investigated using a high-throughput sequencing method. We found significant differences between the microbial community compositions of the water and the sediment. The sediment samples contained more diverse Bacteria and Archaea than did the water samples. Actinobacteria, Betaproteobacteria, Cyanobacteria, and Deltaproteobacteria predominated in the water samples while Deltaproteobacteria, Anaerolineae, Nitrospira, and Dehalococcoidia were the major bacterial groups in the sediment. As for Archaea, Woesearchaeota (DHVEG-6), unclassified Archaea, and Deep Sea Euryarchaeotic Group were detected at higher abundances in the water, whereas the Miscellaneous Crenarchaeotic Group, Thermoplasmata, and Methanomicrobia were significantly more abundant in the sediment. Interactions between Bacteria and Archaea were common in both the water column and the sediment. The concentrations of major nutrients (NO^3-, PO4^3-, SiO3^2- and NH4^+) shaped the microbial population structures in the water. At the higher phylogenetic levels including phylum and class, many of the dominant groups were those that were also abundant in other lakes;however, novel microbial populations (unclassified) were often seen at the lower phylogenetic levels. Our study lays a foundation for examining microbial biogeochemical cycling in sequestered lakes or reservoirs.     

哈雷彗星主尾流的研究

哈雷彗星在日彗距较大时出现长而直的主彗尾（尾流），这是很有趣的。尾流一般是指等离子体尾流；但是，当地球接近彗星轨道面时，尘埃尾流可能叠加到主彗尾上。在一般感光波段宽的彗星底片上很难区分这两种尾流。本文选取哈雷彗星在不同日彗距的5条主尾流，作了光度测量和比较分析。得出沿各尾轴及其垂直方向几个截面的亮度分布、亮度半极大全宽、尾轴的视风差角和真风差角及彗尾长度。在所分析的蓝敏底片上，过近日点前的2个尾流肯定是等离子体尾流，而5个尾流的相似性以及其他证据说明它们主要都是等离子体尾流，尘埃彗尾的污染是次要的。     

磺酸型阳离子树脂的元素分配行为及高精度同位素分析应用

不同元素在离子交换树脂的分配系数是元素纯化和分离的基础,不同酸中各元素分配系数差异可用于设计高效的元素提纯流程,从而被广泛应用于现代高精度同位素分析。本文以AG®50W-X8阳离子树脂为研究对象,以分配系数(Kd)作为量化指标,通过系统实验研究不同元素在该树脂中的分配行为。在前人研究基础上,本实验增加了元素数量和酸的种类,涵盖了金属、类金属、非金属和稀土元素。结果表明：在盐酸和硝酸介质中,几乎所有元素的Kd都与酸度呈负相关,当酸度达到6mol/L时,除Th和Ca以外的所有元素都会被酸洗脱。稀土元素(REEs)和高场强元素在0.1～0.5mol/L稀硝酸和稀盐酸中强烈吸附在树脂上;而一些过渡金属、类金属和非金属元素(如Mo、W、Re、Ir、Sb、Ge、As、Se、Te等)在酸溶液中会形成含氧阴离子,不与阳离子树脂发生吸附。Al、Fe、Se、Pd、Cd、In等元素在盐酸中易与氯离子形成配位化合物或离子团,导致这些离子在盐酸中的分配系数显著降低。在硝酸和盐酸与氢氟酸的混合酸中,除稀土元素外,绝大部分元素随酸度增加Kd迅速降低。稀土元素在盐酸-氢氟酸混合介质中,随着盐酸的浓度增加(从0.1mol/L盐酸-0.2mol/L氢氟酸至6mol/L盐酸-0.2mol/L氢氟酸),稀土元素分配系数（KdREE）具有先增加后降低的趋势。氢氟酸的加入可显著降低Be、Al、Sc、Fe、Sn、Th、U、Ti、Zr、Hf等元素在稀盐酸和稀硝酸中的分配系数,使这些元素几乎不与树脂发生吸附。本研究揭示了不同酸介质中各类元素在阳离子交换树脂上的分配行为存在差异,尤其是氢氟酸的加入可显著改变高场强元素、部分过渡金属和稀土元素的分配系数,为应用该树脂开发和优化适用于高精度金属稳定同位素分析的元素提纯流程(如Li、Mg、K、Sr、Ce、U等)提供了数据支撑,并可有效地减少后续实验设计的工作量。     

寻路地图设计中相关问题研究

以郑州市街头的寻路地图为例,对其设计现状进行了分析,指出了这些地图的特点和其在设计上存在的不足之处.根据寻路地图的目的和用户的特殊性,制作了寻路地图样图,并就其在定向和路线选择等方面进行了试验,对实验结果进行了分析和研究.结果表明地图内容、参考方向和地图符号是影响用户定向和路线选择的主要因素.以此为基础,得出了寻路地图设计中应当遵循的一些规律.     

基于北斗卫星定位技术构建车辆监控系统

考虑GPS／GSM组合模式车辆监控系统的不足,提出了基于北斗卫星定位技术的车辆监控系统解决方案,阐述该车辆监控系统的技术原理和系统框架结构。     

基于栅格空间数据的粤北山区土地可持续利用评价

土地可持续利用是区域发展的立足之本,是可持续发展战略的核心内容之一,进行科学的土地可持续利用评价具有十分重要的意义。选择粤北山区的韶关市作为研究区域,利用遥感和G IS技术,构建一套适合研究区域的土地可持续利用评价指标体系,并提出一个土地可持续利用定量评价模型。然后对评价指标数据进行标准化和空间化处理,对研究区域进行基于栅格空间数据的土地可持续利用评价。最后总结研究区的土地可持续利用状况,提出适合研究区域土地可持续利用的可行性建议。     

球面四元三角网的复杂拓扑关系计算

针对已有球面四元三角网拓扑关系计算方法不能处理带空洞复杂目标的情况,提出了基于公共三角格网来计算球面四元三角网复杂拓扑关系,该方法能准确判断出带空洞复杂目标的拓扑关系,为全球空间分析和应用提供了新的思路。