Recent climate trends on the northern slopes of the Tianshan Mountains, Xinjiang, China     

Hongfeng Zhang  Zhiyun Ouyang  Hua Zheng  Xiaoke Wang 《山地科学学报》2009,6(3):255-265

In arid regions, mountains fulfill important ecological and economic functions for the surrounding lowlands. In the scenario of global warming, mountain ecosystems change rapidly, especially in the arid region of northwestern China. This paper provides an assessment of the changes in temperature and precipitation in the historical records of climate on the northern slopes of the eastern Tianshan Mountains. A Mann-Kendall nonparametric trend and Sen＇s tests are employed to analyze the interannual changes and innerannual variability in temperature and precipitatiofi in the regions of low to high altitude. The present study finds that the largest increases in annual temperature are observed at stations in the low altitude regions. The significant increasing trends in temperature tend to occur mainly in late winter and early spring at stations from middle to high altitude, but in summer and autumn at stations of low altitudes. The increasing trends in annual precipitation are found from the middle to high altitude areas, but decreasing trends are found in the low altitude areas. The significant increasing trends in precipitation occur mostly in winter and earlier spring at stations from the middle to high altitudes, while the increasing and decreasing trend coexists at stations of low altitude with most of the significant trend changes occurring in March, June and August.  相似文献   

2008年以来地图学眼动与视觉认知研究新进展   总被引：7，自引：0，他引：7  

董卫华  廖华  詹智成  刘兵  王圣凯  杨天宇 《地理学报》2019,74(3):599-614

地图是人类日常生活中不可或缺的工具。地图认知作为研究人对地图的感知、学习、记忆、推理和决策的科学,一直以来是地图学基础理论的重要内容。作为地图认知研究的核心,近年来地图视觉认知在相关学科（如心理学、认知科学和计算机视觉）和新的研究手段（如眼动跟踪、脑电和核磁）的促进下取得了一系列新的研究成果。尤其是眼动跟踪方法作为地图视觉认知研究的重要手段之一,越来越受到研究者的关注,为地图视觉认知研究的定量化、实用化提供了有力支撑。本文系统地梳理了2008年以来眼动跟踪方法在地图视觉认知研究中取得的新进展,并将其归纳为6个发展趋势,分别包括：① 刺激材料：从静态地图到动态交互地图;② 研究范围：从地图认知到地图空间认知;③ 实验环境：从实验室环境到真实环境;④ 地图维度：从二维地图到三维地图;⑤ 个体差异：从单一维度到多维度;⑥ 研究目的：从规律探究到实践应用。本文最后总结了未来研究面临的挑战、难点和可能的解决方法,期望能在地图视觉认知研究中起到抛砖引玉的作用。  相似文献   

日照市矿产资源优化配置探析     

贺兆成  庄华 《山东国土资源》2009,25(7):9-10

近年来，日照市高度重视矿产资源优化配置工作，紧紧以整顿和规范矿产资源开发秩序工作为契机，全面推广开采新技术，积极推动小矿整合，促进矿山企业规模化经营，有效提高了矿产资源利用率，取得了良好的社会效益和经济效益。1日照市矿产资源优化配置现状（1）推动资源整合，优化矿山企业空间布局。为解决矿山布局不合理和矿产开发中的“小、散、乱”问题，提高矿产资源节约集约利用水平，该市积极推动小矿整合，切实提高规模化经营水平。按照矿产资源总体规划和整合方案的规定，对限采区、宜采区内的勘查开采实行统一规划、统一管理，确定了矿山整合范围和具体名单，灵活采取兼并、  相似文献   

探针药物法评价磺胺甲基异唑、甘草和连翘对牙鲆CYP2E1活性的影响     

韩现芹  李健  王群  刘淇  韩华  李吉涛  陈萍 《中国海洋大学学报(自然科学版)》2009,39(3)

采用探针药物法研究磺胺甲基异唑(SMZ)、甘草及连翘对牙鲆细胞色素P4502E1 (CYP2E1)活性的影响,为临床合理用药提供参考.将牙鲆随机分为4组,即对照组、SMZ组、甘草组和连翘组.依次每日口灌0.9%的生理盐水、口灌SMZ 150 mg/kg·bw、甘草30 mg/kg·bw和连翘100 mg/kg·bw.连续6 d后,第7天时4组牙鲆同时一次性腹腔注射探针药物氯唑沙宗,分别于注射给药后不同时间点采血.通过HPLC检测探针药物的血药浓度,计算药动学参数,间接评价各组对CYP2E1酶的活性影响.结果表明:氯唑沙宗在4组牙鲆体内代谢的药时曲线均符合二室模型.甘草组和连翘组氯唑沙宗的半衰期分别增加了0.311倍和0.799倍,均差异极显著(P<0.01);SMZ组与对照组差异不显著.药时曲线下面积SMZ组与对照组比较减少了0.277倍,甘草组增加了0.286倍,差异均显著(P<0.05);连翘组增加了0.865倍,差异极显著(P<0.01).总清除率(CL)SMZ组增加了38.83%,连翘组减少了46.88%,均差异极显著(P<0.01);甘草组减少了21.22%,差异显著(P<0.05).说明甘草,连翘对牙鲆CYP2E1的活性均具有明显的抑制作用,连翘的抑制作用高于甘草,SMZ对牙鲆CYP2E1的活性具有诱导作用,差异不显著.  相似文献   

OSL chronology of sand deposits and climate change of last 18 ka in Gurbantunggut Desert,northwest China     

Sheng‐Hua Li  Anchuan Fan 《第四纪科学杂志》2011,26(8):813-818

The development of the Gurbantunggut Desert is mainly controlled by the Westerly wind, and at present has little influence from Indian and Southeast Asian monsoons. A combined study using optically stimulated luminescence (OSL) dating, ground‐penetrating radar (GPR) surveys and climatic proxies analysis was carried out in the southern part of the desert. The chronology extends back to 18 ka and is constructed based on 16 OSL ages from boreholes in the linear dune body and the inter‐dune area. The chronology suggests that sand deposition in the last 18 ka experienced two rapid accumulation phases at 11 and 2.5 ka ago which were also evident from the GPR surveys. These periods relate to increased aridity in the region. Five climate phases are identified from the last 18 ka, based on the OSL chronology and climatic proxy analysis with grain size and magnetic susceptibility measurements. The deglacial period (18.3–10.4 ka) is characterized by climate instability and possible glacial melting events. The Holocene Optimum peaked 8.5 ka and terminated 3.6 ka ago, when the regional climate became arid. OSL samples from the dune body cluster around 2.5 ka, which indicates rapid advance/extension of dune bodies at this time. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

建筑物倾斜与沉降监测结果综合分析   总被引：1，自引：0，他引：1  

花向红  于中伟  蔡华 《地理空间信息》2009,7(1):120-122

介绍建筑物倾斜测量方法，分析某小区地面塌陷后建筑物倾斜监测成果础倾斜与建筑物倾斜关系，分析了建筑物安全状况，为领导决策提供科学依据。  相似文献   

基于Qi(xi,yi)函数的约束Delaunay三角剖分算法     

刘凯  齐华 《地理信息世界》2007,5(3):59-63

利用Qi算法的性质,提出了一种基于Qi(xi,yi)函数的约束Delaunay三角剖分算法。经过比较分析,本文提出的算法降低了时间复杂度,提高了执行效率。  相似文献   

GPS短基线整周模糊度的直接解法   总被引：5，自引：2，他引：3  

邱蕾  花向红  蔡华  伍岳 《武汉大学学报(信息科学版)》2009,34(1)

提出了在位移值较大的情况下(0.7 m),通过多种载波相位组合,解算短基线GPS整周模糊度的方法。导出了在解算过程中保证L1和L2载波的整周模糊度N1和N2为整数的条件,从而将DC(direct calcu-lation)算法[1]不仅推广到大变形的情况,而且推广到短基线GPS整周模糊度的解算,解决了快速准确解算短基线GPS整周模糊度的问题。  相似文献   

Wave Run-up on A Vertical Seawall Protected by An Offshore Submerged Barrier     

张景新  刘桦 《中国海洋工程》2009,23(3):553-564

Submerged barriers are constructed in coastal zones for shoreline or harbor protection or to prevent the beach erosion. In the present study, the wave run-up on a vertical seawall protected by a submerged barrier is analyzed. The physical configurations include a rigid barrier and a long channel of finite depth. For linear water waves, by matching the velocity along the barrier and along the gap, the systems of linear equations about the velocity potentials are obtained. The wave run-up is further analyzed ...  相似文献   

抚顺盆地沉积动力学特征及其聚煤意义   总被引：2，自引：1，他引：2  

张瑞生  王华  吴冲龙 《沉积学报》2001,19(3):375-380

通过对抚顺聚煤盆地的沉积动力学研究及对古城子组主要煤层的煤体形态、沉积构造及夹矸特征、大型树桩化石等的详细观察,对主煤超厚煤层的沉积环境进行了深入细致的分析。结果表明,主煤超厚煤层主要沉积于较深水的沉积环境,内碎屑沉积作用活跃,可作为深水成煤模式的典型代表。  相似文献