Sur la nécessité d'une bonne économie de l'eau     

René Colas 《Aquatic Sciences - Research Across Boundaries》1957,19(1):37-54

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由太阳近红外直接辐射强度遥测大气水汽总含量     

孔琴心  任丽新 《大气科学》1983,7(3):341-346

用一台单色计在地面测量太阳0.873微米和0.942微米辐射强度比值。该比值可以有效地消除气溶胶和雷利散射,仅剩下水汽吸收效应,从而能够较好地确定大气垂直路径和斜程路径的水汽总含量。本文还详细讨论了获得校正曲线的方法。  相似文献   

Simulating nonequilibrium transport of atrazine through saturated soil   总被引：5，自引：0，他引：5  

Mao M  Ren L 《Ground water》2004,42(4):500-508

Atrazine, an herbicide widely used for selective control of grassy weeds in the fields where maize is grown, is a potential ground water contaminant in China and, consequently, there is interest in predicting its mobility in agricultural soils. In this study, we determined the nonequilibrium transport characteristics of atrazine in Shahe soil (Beijing sandy loam) using the advection-dispersion equation, and using a sensitivity analysis, we evaluated the contribution of the uncertainty in a given input parameter to the overall uncertainty in model results. The asymmetrical shape and tailing of the atrazine breakthrough curve (BTC) showed that atrazine was subject to nonequilibrium transport. The observed atrazine BTC was best fitted by the chemical nonequilibrium model with a nonlinear least-squares optimization approach. Results from the sensitivity analysis indicated that the retardation factor was the most sensitive parameter. Considering the reliability of the estimated parameters, the best fit to the atrazine BTC was obtained by fixing the retardation factor based on the linear distribution coefficient, and by calculating the dispersion coefficient from the bromide BTC and the average pore water velocity from the measured data; nonequilibrium parameters were the only unknown parameters that were optimized. Model verification procedures were based on best-fit parameters optimized from one soil column experiment and applied to simulate the transport of atrazine in the duplicate experiment. The results showed there was good agreement between measured and simulated concentrations for atrazine leaching in the soil column.  相似文献   

Paleomagnetic study on the Early Triassic red beds from Jiaocheng,Shanxi Province     

Ruiping?ShiEmail author  Baochun?Huang  Rixiang?Zhu  Shoumai?Ren 《中国科学D辑(英文版)》2004,47(2):108-114

Paleomagnetic and rock magnetic study has been conducted on the Early Triassic red beds of Liujiagou Formation from Jiaocheng, Shanxi Province. Hematite was shown as the main magnetic mineral. After eradicating an initial viscous component at room temperature to ~100°C–200°C, thermal demagnetization shows that most samples contain two remanence components, intermediate-temperature remanence component at 250°C–500°C and high-temperature component at 500°C–680°C. The intermediate-temperature component has a negative fold test at the 95% confidence level. And the pole position of the intermediate-temperature component in geographic coordinates is correlated with the Middle Jurassic reference pole of the North China Block (NCB) within the 95% confidence, suggesting that it might be a remagnetization component acquired during the Yanshanian period. The high-temperature component contains both reversal and normal polarities with positive fold test and C-level positive reversal test at the 95% confidence level, which suggests that this high-temperature component can be regarded as primary magnetization. Comparison of this newly obtained Early Triassic paleopole with the coeval mean pole of the Ordos Basin suggests that a locally relative rotation may have happened between the Ordos and the Jiaocheng area of Shanxi Province. This rotation may be related with two faults: one is Lishi big fault separating Ordos from Shanxi and the other is Jiaocheng big fault, which is situated in the southeast of sampling locality and was still in motion during the Cenozoic.  相似文献   

Global tectonics and the plate motion obtained from the ITRF97 station velocity vectors   总被引：2，自引：0，他引：2  

马宗晋  任金卫  张进 《中国科学D辑(英文版)》2003,46(3):193-199

~~Global tectonics and the plate motion obtained from the ITRF97 station velocity vectors@马宗晋 @任金卫 @张进~~  相似文献   

基于网络数据库的气象图形图像软件          下载免费PDF全文

张陇瑛 《山西气象》2004,(4):40-42

土壤墒情是反映一地土壤含水量多少的主要指标，墒情的好坏直接影响着农作物的生长。对于土壤墒情的计算和编报，曲沃县气象站经历了从完全的由人工查算计算编报，到用Basic语言编程计算编报，再到以后的Excel表格计算几个阶段。但这几种方法要么是计算量大，要么是界面不友好不易控制，要么是对操作计算机人员水平要求过高，稍不留心可能造成计算错误等多种不便。应用VFP语言可容易的编出具有Windows风格的程序，既方便操作，又能保证计算的精确度。  相似文献   

用sPn计算内蒙地震的震源深度   总被引：11，自引：6，他引：11  

任克新  邹立晔  刘瑞丰  刘敬光 《地震地磁观测与研究》2004,25(3):24-31

震源深度是地震定位的一个重要参数。本文讨论了用sPn测定震源深度的可能性。sPn对于测定地壳内震源深度具有重要意义。本文笔者利用记录到的sPn震相计算了2003年8月16日发生在我国内蒙地区地震的震源深度，并对该方法在日常工作中的应用进行了讨论。  相似文献   

Posteruption glacier development within the crater of Mount St. Helens, Washington, USA     

Steve P. Schilling  Paul E. Carrara  Ren A. Thompson  Eugene Y. Iwatsubo 《Quaternary Research》2004,61(3):325-329

The cataclysmic eruption of Mount St. Helens on May 18, 1980, resulted in a large, north-facing amphitheater, with a steep headwall rising 700 m above the crater floor. In this deeply shaded niche a glacier, here named the Amphitheater glacier, has formed. Tongues of ice-containing crevasses extend from the main ice mass around both the east and the west sides of the lava dome that occupies the center of the crater floor. Aerial photographs taken in September 1996 reveal a small glacier in the southwest portion of the amphitheater containing several crevasses and a bergschrund-like feature at its head. The extent of the glacier at this time is probably about 0.1 km². By September 2001, the debris-laden glacier had grown to about 1 km² in area, with a maximum thickness of about 200 m, and contained an estimated 120,000,000 m³ of ice and rock debris. Approximately one-third of the volume of the glacier is thought to be rock debris derived mainly from rock avalanches from the surrounding amphitheater walls. The newly formed Amphitheater glacier is not only the largest glacier on Mount St. Helens but its aerial extent exceeds that of all other remaining glaciers combined.  相似文献   

渤海湾牡蛎礁平原中部兴坨剖面全新世地质环境变迁   总被引：9，自引：8，他引：9  

李建芬　王宏李凤林  张金起张玉发　王云生 《地质通报》2004,23(2):169-176

渤海湾牡蛎礁平原中部兴坨剖面的有孔虫组合划分为5种沉积环境7个带(亚环境)，从下向上依次为晚更新世陆相(Ⅶ带)、早全新世海陆过渡相(Ⅵ带：沿海低地与潮间带)、中晚全新世海相(Ⅴ带：潮下带-浅海，Ⅳ带：低潮线附近)、晚全新世海陆过渡相(Ⅲ带：开放潮间带，Ⅱ带：渴湖)和河流泛滥相(Ⅰ带：古土壤及洪积层)。^14C确定了全新世底泥炭始于9486 cal BP，Ⅳ带始于约4696 cal BP。Ⅱ带所处的渴湖环境，从约4000 cal BP直至隋唐温暖期之前，历时约2700年。隋唐暖期古土壤发育向南东减弱至逐渐消失，说明在比兴坨更靠近渤海湾的地方，潟湖持续的时间更长。广泛存在的潟湖，是牡蛎礁平原晚全新世的重要地貌景观。  相似文献   

信息化时代地震观测技术的产业化问题     

周挚  山秀明  任勇  李倩  王征  郭天乐 《国际地震动态》2004,(6):8-14

国家间的竞争集中表现为前瞻性技术领域的竞争，占领技术制高点成为各国国家发展的基本取向。本文结合地震观测现状和现代信息网络技术、自动化控制技术的进展，概述了地震观测技术产业化发展的社会需求和科学需求，从国家科技发展战略层次上初步探讨了地震观测技术产业化发展的重要性和必然性。  相似文献