Damage Characteristics of Altered and Unaltered Diabases Subjected to Extremely Cold Freeze–Thaw Cycles

Altered and unaltered diabases are commonly deposited on hydrothermally mineralized slopes. To study their damage characteristics during freeze–thaw cycles, they were sampled from Cihai iron ore mine located in an extremely cold region, Xinjiang, China and examined using acoustic and X-ray diffraction experiments to analyze the differences in their main mineral components and explore their damage characteristics under freeze–thaw conditions. Based on the results of these experiments, their damage and degradation patterns were obtained and the evolution of their physical characteristics including the rock mass loss rate (L _F), rock strength loss rate (R _σ ), P-wave velocity loss rate (V _l), and freeze–thaw coefficient (K _f) was analyzed. In addition, two groups of equations were established to characterize the relationships of these physical and mechanical properties of the rock specimens with the number and temperature of freeze–thaw cycles. The results show that the mineral composition of diabase changes during its alteration, showing increased clay and calcite, and the degradation and evolution patterns of the physical and mechanical parameters (L _F, R _σ , V _l, and K _f) of the altered rocks during freeze–thaw cycles are different from those of diabase, with the altered diabase exhibiting greater damage than the diabase.     

广西气象站数据图文报告自动化制作系统的设计与实现

应用系统分布式模块结构的设计思路和基本功能开发了广西气象观测站数据的图文自动化制作系统平台,实现了信息自动转换、存储和图文报告制作的自动化.     

湖南省攸县兰村矿区深部龙潭组及煤层发育特征

攸县兰村矿区深部勘查区位于郴耒煤田北部,含煤地层二叠系上统龙潭组含煤层数较多且结构复杂,通过岩性特征、物性特征以及煤层特征等分析,基本查明了研究区煤层的赋存特征。结果显示：龙潭组上段1、2、6、9煤层为大部分可采不稳定煤层,3、4、5、7煤层为局部可采不稳定煤层,8、10、11、12煤层为不可采煤层;龙潭组下段含煤13～16层,只有16煤层在柳树冲区段大部分可采,为不稳定煤层。煤层可采范围的确定,为煤炭资源科学规划、合理开发及矿井安全提供了地质依据。     

Hydrogeochemical and isotopic evidence of groundwater evolution and recharge in aquifers in Beijing Plain, China

An investigation was conducted in Beijing to identify the groundwater evolution and recharge in the quaternary aquifers. Water samples were collected from precipitation, rivers, wells, and springs for hydrochemical and isotopic measurements. The recharge and the origin of groundwater and its residence time were further studied. The groundwater in the upper aquifer is characterized by Ca-Mg-HCO₃ type in the upstream area and Na-HCO₃ type in the downstream area of the groundwater flow field. The groundwater in the lower aquifer is mainly characterized by Ca-Mg-HCO₃ type in the upstream area and Ca-Na-Mg-HCO₃ and Na-Ca-Mg-HCO₃ type in the downstream area. The δD and δ¹⁸O in precipitation are linearly correlated, which is similar to WMWL. The δD and δ¹⁸O values of river, well and spring water are within the same ranges as those found in the alluvial fan zone, and lay slightly above or below LMWL. The δD and δ¹⁸O values have a decreasing trend generally following the precipitation → surface water → shallow groundwater → spring water → deep groundwater direction. There is evidence of enrichment of heavy isotopes in groundwater due to evaporation. Tritium values of unconfined groundwater give evidence for ongoing recharge in modern times with mean residence times <50 a. It shows a clear renewal evolution along the groundwater flow paths and represents modern recharge locally from precipitation and surface water to the shallow aquifers (<150 m). In contrast, according to ¹⁴C ages in the confined aquifers and residence time of groundwater flow lines, the deep groundwater is approximately or older than 10 ka, and was recharged during a period when the climate was wetter and colder mainly from the piedmont surrounding the plain. The groundwater exploitation is considered to be “mined unsustainably” because more water is withdrawn than it is replenished.     

简析CINRAD/CD型新一代天气雷达伺服系统故障排除方法

文章介绍了CINRAD/CD型新一代天气雷达伺服系统组成,分析总结了典型故障的排除方法,并指出了系统使用维护过程中的注意事项。     

Study on visualization of virtual city model based on internet

With the rapid development of computer graphics, distributed-computing and Internet, it is possible to achieve Internet-based virtual city. This paper dwells on the method of the terrain and its feature modeling and complex entity modeling in the virtual city. Then, discusses the method for Internet-based virtual city 3D visualization and the design of the Browser/Server architecture of the system of virtual city in the network environment. Finally, Java and Java 3D are used to show an experiment example, and the related conclusion about Internet-based virtual city 3D displaying and the client-side interactive operation is given.     

Seasonal changes in the relationship between species richness and community biomass in grassland under grazing and exclosure, Horqin Sandy Land, northern China

How species diversity–productivity relationships respond to temporal dynamics and land use is still not clear in semi-arid grassland ecosystems. We analyzed seasonal changes of the relationships between vegetation cover, plant density, species richness, and aboveground biomass in grasslands under grazing and exclosure in the Horqin Sandy Land of northern China. Our results showed that in grazed and fenced grassland, vegetation cover, richness, and biomass were lower in April than in August, whereas plant density showed a reverse trend. Vegetation cover during the growing season and biomass in June and August were higher in fenced grassland than in grazed grassland, whereas plant density in April and June was lower in fenced grassland than in grazed grassland. A negative relationship between species richness and biomass was found in August in fenced grassland, and in grazed grassland the relationship between plant density and biomass changed from positive in April to negative in August. The relationship between the density of the dominant plant species and the total biomass also varied with seasonal changes and land use (grazing and exclosure). These results suggest that long-term grazing, seasonal changes, and their interaction significantly influence vegetation cover, plant density, and biomass in grasslands. Plant species competition in fenced grassland results in seasonal changes of the relationship between species richness and biomass. Long-term grazing also affects seasonal changes of the density and biomass of dominant plant species, which further affects the seasonal relationship between plant density and biomass in grasslands. Our study demonstrates the importance of temporal dynamics and land use in understanding the relationship between species richness and ecosystem function.     

个旧锡多金属矿集区高松矿田矿化元素局部富集的奇异性特征

多重分形理论能够有效地分析地球化元素局部富集和贫化规律。对取自个旧高松矿田的1 783件断裂构造地球化学样品的13种元素进行了多重分形统计以及局部奇异性方法分析。结果表明:多重分形维谱函数α-f(α)曲线呈连续上凸的特征,曲线的不对称反映了元素局部富集程度差异,并据此将13种元素划分为包含Sn、Cu、Pb、Ag、As、Mn在内的主要成矿元素组合以及包含Zn、Sb、Cd、W、Mo、Bi、Hg的次要成矿元素或伴生元素组合。多重分形的特征值τ″(1)以及Dq的变化规律表明:在主要成矿元素中,Sn在断裂空间上局部富集程度最高,其次为Ag,而Cu相对最低,各元素的τ″(1)值与对应的变异系数的大小具有较为显著的相关性;各元素在空间上的奇异性指数α增强了地球化学富集地段的指示信息,可以作为判别局部富集的重要参数。运用多重分形方法可揭示矿化元素局部富集的奇异性特征以及空间局部富集规律。     

Influence of dune stabilization on relationship between plant diversity and productivity in Horqin Sand Land, Northern China

The city of Split has been developing continuously since the construction of the Diocletian Palace (287–305) to the present time. Detailed engineering geological investigations, with the recorded documents, have been performed since 1970. Further development and expansion of the city require an urban engineering geological map to be developed as a main prerequisite for the geotechnical and seismic zonation. In this paper a review of engineering geological conditions at the area of Split City (cca 25 km²) is given. Those conditions are interpreted on the basis of available data from geotechnical reports (about stratigraphical units, their lithological composition and physical and mechanical properties) and limited field survey. Zones with different ground conditions regarding rock properties are delineated in the form of lithological complex, engineering geological mapping units for medium-scale maps. The area of the city of Split, built of foraminifera limestones (E_1,2), clayey glauconitic limestones (E₂^1,2 E_{2}^{1,2} ), and flysch sediments (E_2,3), is divided into five lithological complexes, which presents unique combination of individual lithological type for which it is possible to indicate general behavior of the whole. The paper also provides short review of other environmental conditions (active geomorphological processes, hydrological and hydrogeological conditions, as well as seismic conditions), which are intended as a guide to the sort of environmental data that could be collected by more detailed studies during the course of the zoning process.