试论少数民族地区的生态化旅游开发

生态化旅游开发是有别于传统的旅游开发的一种可持续开发与发展的理念，它追求的是生态、社会和经济综合效益的最大化，应该成为旅游开发与旅游业发展的主要方向。民族地区的旅游开发具有特定的区域生态特征。其生态化旅游开发的核心问题是旅游环境容量的确定与旅游环境的保护、民族特色与民族文化的弘扬以及注重旅游经济发展过程中旅游业的拉动效应及其依托性之间的关系处理等。     

Effect of a thermokarst lake on soil physical properties and infiltration processes in the permafrost region of the Qinghai-Tibet Plateau,China

Changes in the hydrological processes in alpine soil constitute one of the several key problems encountered with studying watershed hydrology and ecosystem stability against the background of global warming. A typically developing thermokarst lake was chosen as a subject for a study using model simulation based on observations of soil physical properties, infiltration processes, and soil moisture. The results showed that the selected thermokarst lake imposed certain changes on the soil infiltration processes and, with the degree of impact intensifying, the initial infiltration rate decreased. The greatest reduction was achieved in the area of moderate impact. However, the stable infiltration rate and cumulative infiltration gradually increased in the surface layer at a depth of 10 and 20 cm, both decreasing initially and then increasing, which is correlated significantly with soil textures. Moreover, the cumulative infiltration changed in line with steady infiltration rate. Based on a comparative analysis, the Horton model helps better understand the effect on the soil infiltration processes of the cold alpine meadow close to the chosen thermokarst lake. In conclusion, the formation of the thermokarst lake reduced the water holding capacity of the alpine meadow soil and caused the hydraulic conductivity to increase, resulting in the reduction of runoff capacity in the area of the thermokarst lake.     

小口径加筋砼灌注桩应用初探

在小口径加筋砼灌注桩试桩基础上结合工程实例对小口径加筋砼灌注桩的设计、施工和检测进行了初步探讨     

河北沿海海侵灾害初探

文中以包含海进、海岸侵蚀和海水入侵的广义“海侵”概念,论述河北沿海地区海侵现状及其危害,探讨海侵产生的自然原因和人为活动的影响,在此基础上,评估海侵发展趋势。     

Development of gullies and sediment production in the black soil region of northeastern China

Gully erosion is an important environmental hazard in the black soil region of northeastern China. It is a primary sediment source in the region which needs appropriate soil conservation practices. Gully incision in rolling hills typical of this region was monitored using real-time kinematic GPS to assess the rates of gully development and the resultant sediment production. From 2002 to 2005, gully heads in the study area retreated between 15.4 and 33.5 m, giving an average retreat rate of 8.4 m yr^− 1. Field measurements showed that total sediment production due to gully erosion during the three years ranged between 257 and 1854 m³ yr^− 1, which is equivalent to 326 to 2355 t yr^− 1, with gully-head retreat accounting for 0 to 21.7% (4.4% in average). The sediment delivery ratio was especially high during the summer rainy season (56% in average). Sediment production by ephemeral gullies and permanent gullies was 1.5 times greater than that from surface erosion. Gully heads retreated faster in the spring freeze–thaw period than in the summer. The stage of gully development could be identified based on short-term changes in the gully erosion rate.     

Rapid exhumation of basement rocks along the northern margin of the North China craton in the early Jurassic: evidence from the Xiabancheng Basin,Yanshan Tectonic Belt

Early Mesozoic Basins in the Yanshan Fold–Thrust Belt (YFTB), located along the northern margin of the North China Craton (NCC), record significant intraplate deformation of unknown age. In this article, we present evidence for the rapid exhumation of high‐grade basement rocks along the northern margin of the NCC in the Early Mesozoic. U–Pb geochronology of detrital zircons constrains the maximum depositional ages of syntectonic sedimentary units that formed during the unroofing of basement rocks and plutons in the Xiabancheng Basin. In the Early Mesozoic, the Xiabancheng Basin recorded a dramatic transformation in depositional environments, related to a significant change in the regional tectonic setting. In this study, the tectonic evolution of the YFTB is established from paleocurrent data and U–Pb zircon ages of sandstone and granitic gravels of the Xingshikou Formation, Xiabancheng Basin. The paleocurrent direction of meandering fluvial facies in the Triassic Liujiagou and Ermaying Formations are from east to west. In contrast, the overlying Xingshikou Formation consists of alluvial fan facies with paleocurrent directions from north‐northwest to south‐southeast. The lower and middle segments of the Xingshikou Formation record rapid exhumation of basement rocks along the northern margin of the NCC. U‐Pb ages of detrital zircons within the Xingshikou Formation are characterized by three major U–Pb age groups: 2.2–2.5 Ga, 1.7–1.8 Ga and 193–356 Ma. From 193 Ma to 356 Ma, a subsidiary peak occurs at 198 ± 5 Ma, constraining the sedimentation age of the Xingshikou Formation to the Early Jurassic. Zircon from the Wangtufang pluton in the northern portion of the Xiabancheng Basin yields U–Pb ages of 191 ± 1 Ma and 207 ± 1 Ma. Within error, these crystallization ages are identical to detrital zircon ages of 206 ± 1 Ma and 206 ± 2 Ma obtained for granitic gravel clasts in the Xingshikou Formation. Thus, the Wangtufang pluton and surrounding basement rocks must have experienced rapid uplift and exhumation during the Early Jurassic. The onset of exhumation along the northern margin of the NCC occurred at ca. 198–180 Ma.     

Physicochemistry and Mineralogy of Storm Dust and Dust Sediment in Northern China

Dust sediments collected from 1995 to 1998 in Beijing, Dunhuang, Inner Mongolia, Kashi, the Kunlun Mountains, Lanzhou, Ningxia, the Taklimakan Desert, and Xi‘an, China, were characterized in terms of their physical, chemical, and mineralogical properties. Most aerosols and dust analysed ranged in texture from silty clay to clay loam. Their median particle diameters (Mds) generally ranged between 5 to 63μm,coinciding with those of loess from central China and the finest sand from northwestern China. The dust sediments were characterized by a predominance of SiO2 and Al2O3, followed by K2O. Their SiO2/Al2O3and K2O/SiO2 molar ratios ranged from 5.17 to 8.43 and from 0.009 to 0.0368, respectively. The mass concentration spectrum during a dust storm showed a single peak, rather than the triple peak generally observed under clear sky conditions. The dominant minerals were chlorite, illite, calcite, and dolomite.These physical, chemical, and mineralogical properties were consistent with those of aeolian soils and loess in western and central China. The results suggest that aerosols and fine-gained fractions of dust sediments collected in northern China are mainly composed of soil material transported from the arid and semiarid regions of China and Mongolia by prevailing winds. The rate of deposition and properties of dust falling on eastern China were strongly influenced by meteorological conditions, season, latitude, longitude, and altitude of the sampling sites.     

基于时间序列法的北京市需水量预报(英文)

It is essential to establish the water resources exploitation and utilization planning,which is mainly based on recognizing and forecasting the water consumed structure rationally and scientifically.During the past 30 years(1980-2009),mean annual precipitation and total water resource of Beijing have decreased by 6.89% and 31.37% compared with those perennial values,respectively,while total water consumption during the same period reached pinnacle historically.Accordingly,it is of great significance for the harmony between socio-economic development and environmental development.Based on analyzing total water consumption,agricultural,industrial,domestic and environmental water consumption,and evolution of water consumed structure,further driving forces of evolution of total water consumption and water consumed structure are revealed systematically.Prediction and discussion are achieved for evolution of total water consumption,water consumed structure,and supply-demand situation of water resource in the near future of Beijing using Time Series Forecasting Method.The purpose of the endeavor of this paper is to provide scientific basis for the harmonious development between socio-economy and water resources,for the establishment of rational strategic planning of water resources,and for the social sustainable development of Beijing with scientific bases.     

哈罗铁路沿线沉积物粒度特征

哈罗铁路开通对沿线资源的开发具有重要意义,然而自开通以来饱受风沙危害.对铁路沿线及防沙体系内沉积物粒度特征参数进行了对比分析,以期为该线风沙危害的科学防治提供有益参考.结果表明:(1)铁路沿线沉积物组成以中细沙为主,灌丛沙地分选性中等至很差,偏度以近对称为主,峰度中等至很窄;戈壁区沉积物整体分选性较差,偏度以极正偏为主...     

Automatic mapping of lunar landforms using DEM-derived geomorphometric parameters

Developing approaches to automate the analysis of the massive amounts of data sent back from the Moon will generate significant benefits for the field of lunar geomorphology. In this paper, we outline an automated method for mapping lunar landforms that is based on digital terrain analysis. An iterative self-organizing (ISO) cluster unsupervised classification enables the automatic mapping of landforms via a series of input raster bands that utilize six geomorphometric parameters. These parameters divide landforms into a number of spatially extended, topographically homogeneous segments that exhibit similar terrain attributes and neighborhood properties. To illustrate the applicability of our approach, we apply it to three representative test sites on the Moon, automatically presenting our results as a thematic landform map. We also quantitatively evaluated this approach using a series of confusion matrices, achieving overall accuracies as high as 83.34% and Kappa coefficients (K) as high as 0.77. An immediate version of our algorithm can also be applied for automatically mapping large-scale lunar landforms and for the quantitative comparison of lunar surface morphologies.