格尔木河水质现状及生态风险评估

为了解经济迅速发展背景下格尔木河流域水体中痕量元素分布、水环境质量现状和生态风险,对格尔木河9个采样点水样21种痕量元素的分布及相关性进行了分析,以Cu、Zn、Hg、Cd、Cr和Pb为目标重金属,评估了格尔木河水质现状及生态风险。结果表明:重金属Pb浓度在所有水样中均低于检出限,其它痕量元素浓度在0.001(Cd)～6297.013(Sr)μg·L~(-1)范围变化。根据相关性分析,推测格尔木河水体中Li、Sc、Ti、V、Cu、Ge、Rb、Sr、Mo、Cd来源可能相同。采样点水样6种重金属浓度均达到地表水环境质量I类的标准。采用5种方法评价了格尔木河水质现状,研究区水质处于无污染的理想状态。格尔木河重金属引发的潜在生态风险处于低风险水平(生态风险指数变化范围为0.35～0.68)。     

中国生态交错带（英文）

生态交错带（Ecotone）是指两个群落或两类生态系统之间的过度带,具有脆弱、敏感和易变等特性。20世纪70年代以来,在典型生态系统研究的基础上,生态交错带逐步成为生态学研究的重点。中国地域广阔,地质、气候、植被等生态类型复杂多变,蕴育了不同类型、不同尺度和不同规模的多种生态交错带,不仅为科学研究奠定了广阔空间,而且对我国经济、社会发展,以及文化多样性保护具有重要支撑作用。本文根据我国大尺度下生态交错带的地理分布及其生态环境特点,构建了以土地利用类型、自然气候特征和农业经济发展＂三位一体＂指标体系,并以此为依据对中国典型生态交错带进行了划分和空间分布范围的界定;在此基础上,分别对北方森林草原交错带、北方农牧交错带、西北荒漠绿洲交错带、西南川滇农林牧交错带和东部海陆交错带的动态变化、基本特征和存在问题进行了研究,对全面认识我国生态交错带自然演变规律,促进区域生态环境保护和优化经济发展具有重要意义。     

柴达木盆地盐湖锂矿床成矿过程及分布规律

柴达木盆地盐湖蕴藏230×10~4t锂,集中分布在别勒滩、东西台等4个盐湖,占我国卤水锂资源总量~80%,战略资源地位不言而喻。近年来提锂技术及工程化研究倍受重视,而对盐湖锂矿成因和分布规律的了解凸显不足,锂矿资源流失严重与之不无关联。研究查明,昆仑山高温热泉群含锂泉水长期注入洪—那河,流入终端盐湖,蒸发富集成矿;锂的年输入通量748.8 t,结合区内盐湖锂矿总储量保守估算,成矿期始于14 ka BP之后;洪—那河早期主要流向别勒滩,在山前冲积扇向北推进、扇前河改道北流后,方才形成含锂河水当前分配格局。据此,破解了别勒滩锂矿在研究区储量最大的原由。还查明了锂矿床仅存在于别勒滩,而在达布逊等3个区段不能成矿的原因。阐明了锂的来源与新生代火山喷发岩、深部岩浆房、昆仑大断裂活动有关,以及含锂热水持续远程输送至盐湖成矿的地貌和水文气候动因。企业应当根据锂的分布规律和矿床特征,迅速转变钾肥生产模式。     

科技旅游资源分类及价值评价

科学地区分和评价旅游资源,对有效地规划和开发旅游资源,促进区域旅游业发展具有重要的实践意义。作为现代旅游业重要组成部分的科技旅游,在旅游实践中发挥着越来越重要的作用。建立一个科学、全面的科技旅游资源分类与评价体系,有利于合理有效地开发科技旅游资源,促进科技旅游良好发展。本文首先简述了国内外有关旅游资源分类及评价的相关研究,其次在分析了科技旅游资源的概念与特征的基础上,综合考虑了旅游资源分类的国家标准以及其他分类方法,从而建立了科技旅游资源的分类体系。以此为基础,运用特尔菲法和层次分析法的同时,参考了旅游资源评价的国家标准和其他评价方法,定性与定量相结合,构建了科技旅游资源的评价体系和等级划分标准,以期为科技旅游资源的开发、发展决策提供理论依据。     

Spatial and temporal distribution of precipitation based on corrected TRMM data around the Hexi Corridor, China

Accurate rainfall distribution is difficult to acquire based on limited meteorological stations, especially in remote areas like high mountains and deserts. The Hexi Corridor and its adjacent regions （including the Qilian Mountains and the Alxa Plateau） are typical districts where there are only 30 available rain gauges. Tropical Rainfall Measuring Mission （TRMM） data provide a possible solution. After precision analysis of monthly 0.25 degree resolution TRMM 3B43 data from 1998 to 2012, we find that the correlations between TRMM 3B43 estimates and rain gauge precipitation are significant overall and in each station around the Hexi Corridor; however, the biases of annual precipitation differ in different stations and are seriously overestimated in most of the sites. Thus, Inverse Distance Weighting （IDW） interpolation method was used to rectify TRMM data based on the difference between TRMM 3B43 estimates and rain gauge observations. The results show that rectified TRMM data present more details than rain gauges in remote areas where there are few stations, alt- hough they show high coherence of distribution. Precipitation decreases from southeast to northwest on an annual and seasonal scale. There are three rainfall centers （〉500 mm） including Menyuan, Qilian and Toson Lake, and two low rain- fall centers （〈50 mm） including Dunhuang and Ejin Banner. Meanwhile, precipitation in most of the study area presents an increasing trend; especially in northern Qilian Mountains （〉5 mm/a）, Badain Jaran Desert （〉2 mm/a）, Toson Lake （〉20 mm/a） and Qingtu Lake （〉20 ram/a） which shows a significant increasing trend, while precipitation in Hala Lake （〈-2 mm/a） and Tengger Desert （〈-3 mm/a） demonstrates a decreasing trend.     

Exact solution of entanglement of the double Jaynes—Cummings model without rotating wave approximation

This paper investigates the influences of atom--field coupling and dipole--dipole coupling for atoms on the entanglement between two atoms by means of concurrence. The results show that the sudden death occurs when the atom--field coupling is strong enough, and the collapse and the revival appear when the dipole--dipole interaction is strong enough.     

内蒙古大克泊碱湖氮移除及其影响因素

为了研究碱湖N₂O释放速率及其对盐度与pH的响应,选取内蒙古大克泊碱湖的五个沉积物样点,采用¹⁵N同位素标记模拟实验,研究反硝化和厌氧氨氧化的速率、相对比例和气体产生情况,揭示高盐和高pH对碱湖氮移除的影响。发现大克泊湖潜在氮移除速率为0~16.06 n mol N mL-1 h-1,潜在反硝化速率为0~12.62 n mol N mL-1 h-1,潜在厌氧氨氧化速率为0~9.81 n mol N mL-1 h-1;当盐度34.00 g·L-1与pH 10.22时,厌氧氨氧化对氮移除贡献较大,达到43.18%~71.79%。反硝化过程气体产物以N₂为主,几乎无N₂O气体释出。另外,该区域潜在氮移除速率与pH呈正相关关系,与TOC、NO-₃、HCO-₃呈负相关关系;未发现氮移除速率与盐度之间的相关关系。因此,在研究的碱湖中,氮移除过程中主要为N₂排放,而N₂O低于检测水平;氮移除过程的影响因素复杂且不限于最主要的环境变量(盐度与pH)。这些结果为研究湖泊N₂O排放提供了数据基础。     

Focal Mechanism Solutions and Stress Field Inversion of Moderately Strong Earthquakes in the Northern Tianshan Area

Using the focal mechanism solutions of 24 moderately strong earthquakes in the northern Tianshan area, we carried out system cluster and stress field inversion analysis. The result indicates that, the focal mechanism solutions of moderately strong earthquakes are mainly dipslip reverse faulting in the northern Tianshan area. The principal rupture planes of earthquakes are NW-oriented. It is basically consistent with the strike of earthquake structure in its adjacent area. The direction of the principal compression stress P axis is nearly NS, and its inclination angle is small; while the inclination angle of the principal extensional stress T axis is large. It shows that the regional stress field is mainly controlled by the near-NS horizontal compressive stress. The direction of the maximum principal stress shows a gradation process of NNE-NS-NW from east to west.     

Experimental research on physical properties of saline soil subgrade filler in Chaerhan region

In order to improve the engineering stability of saline soil of high chloride content in the Chaerhan salt lake region, six typical characteristics saline soil samples were selected, and tests on their...     

Millennial-scale evolution of Hunshandake Desert and climate change during the Holocene in Inner Mongolia,northern China

The Hunshandake Desert is located at the northern edge of the East Asian monsoon region,and its natural environment is sensitive to monsoonal changes.Geologic records suggest that desert evolution corresponding to climate change had experienced several cycles in the Holocene,and the evolutionary process can be distinguished by four dominant stages according to changing trends of the environment and climate.(1) Holocene Ameliorative Period(11.0-8.7 cal ka B.P.),when the desert area gradually shrank following an approaching warm-wet climate and strengthening summer monsoon.(2) Holocene Optimum(8.7-6.0 cal ka B.P.),when the majority of moving sand dunes were stabilized and vegetation coverage quickly expanded in a suitable warm-wet climate and a strong summer monsoon.(3) Holocene Multivariate Period(6.0-3.5 cal ka B.P.),during a low-amplitude desert transformed between moving and stabilized types under alternating functions of cold-dry with warm-wet climate,and winter monsoon with summer monsoon.(4) Holocene Decay Period(since 3.5 cal ka B.P.),when the desert area tended to expand along with a weakened summer monsoon and a dry climate.