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美国应用RUSLE测定花生栽培及覆盖对土壤流失的影响 被引量:4
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作者 龙锦林 《水土保持科技情报》 2002年第2期31-34,共4页
Truman等人对 8个田间试验小区 ( 4 0m2 )中的径流和产沙量进行为期 3a的测定 ,以确认花生栽培措施及地面覆盖状况对径流和泥沙流失的影响。小区设于Tifton壤质砂土上 ,并在每个生长季节有 4~ 8次的 4个 3 0min模拟降雨试验 (I=63 5mm... Truman等人对 8个田间试验小区 ( 4 0m2 )中的径流和产沙量进行为期 3a的测定 ,以确认花生栽培措施及地面覆盖状况对径流和泥沙流失的影响。小区设于Tifton壤质砂土上 ,并在每个生长季节有 4~ 8次的 4个 3 0min模拟降雨试验 (I=63 5mm h)。对径流量和泥沙流失量的测定是在持续休闲地、裸露地、单行花生区、双行花生区的 4种土壤覆盖状况下进行。在作物成熟和收获期 ,覆盖率 (P)和叶面积指数 (A)增加到最大值 ,然后呈现稳定的状态。单行花生区和双行花生区的P与自播种以来的天数 (D)具有相关性 ,单行花生区和双行花生区的A与P相关 ,单行花生区和双行花生区的径流量是持续休闲地或裸露地的 1 8,泥沙流失量是 1 63。而双行花生区的径流量和泥沙流失量是单行花生区的 1 3。持续休闲地区和裸露地区的侵蚀率的变化范围分别为 4~2 4kg·hm2 ·h (MJ·hm2 ·mm)和 2~ 3 6kg·hm2 ·h (MJ·hm2 ·mm)。土壤流失率 (WS)的变化范围为 0 0 1~ 2 61。覆盖率在作物的生育期Ⅲ最大 ,而WS 在作物生育期Ⅲ最小 ,在作物成熟期或收获期有所上升。结果表明双行花生栽培等管理措施 ,能够促进生育初期花生株冠的发育 ,减少易遭暴雨径流侵蚀的土壤裸露期 ,从而减少径流和土壤流失 ,保护珍贵的自然资源。 展开更多
关键词 覆盖因素 人工模拟降雨量 RUSLE USLE 美国
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提高小功率短波电台覆盖范围的措施 被引量:7
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作者 陈光宇 《广播电视信息》 2014年第2期90-93,共4页
本文对影响短波覆盖效果的各种因素进行了分析,并提出了一些关于提高小功率短波电台覆盖范围的措施,同时,从实践经验出发,介绍了在采取各种措施时,应注意的一些问题。
关键词 小功率短波电台 覆盖范围影响因素 采取措施 注意事项
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Generating test cases for software configuration testing 被引量:2
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作者 聂长海 徐宝文 《Journal of Southeast University(English Edition)》 EI CAS 2004年第1期26-30,共5页
Software configuration testing is used to test a piece of software with all kinds of hardware to ensure that it can run properly on them. This paper generates test cases for configuration testing with several common m... Software configuration testing is used to test a piece of software with all kinds of hardware to ensure that it can run properly on them. This paper generates test cases for configuration testing with several common methods, such as multiple single-factor experiments, uniform design, and orthogonal experiment design used in other fields. This paper analyzes their merits and improves the orthogonal experiment design method with pairwise testing, and decreases the testing risk caused by incomplete testing with a method of multiple-factors-covering. It presents a simple factor cover method which can cover all the factors and pairwise combinations to the greatest degree. Some comparisons of these methods are made on the aspects of test suite scale, coverage, and usability, etc.. 展开更多
关键词 Computer hardware TESTING
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用智能规划解空间树法生成测试数据 被引量:1
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作者 李杨 宋克非 《光学精密工程》 EI CAS CSCD 北大核心 2011年第7期1695-1700,共6页
讨论了软件测试中常用的两因素组合覆盖测试方法。针对该方法求解困难,并考虑系统中各种因素以及因素间的制约关系对解空间树法生成测试数据产生的影响,提出了采用基于智能规划的解空间树法来生成测试数据。该方法将所有的可用测试数据... 讨论了软件测试中常用的两因素组合覆盖测试方法。针对该方法求解困难,并考虑系统中各种因素以及因素间的制约关系对解空间树法生成测试数据产生的影响,提出了采用基于智能规划的解空间树法来生成测试数据。该方法将所有的可用测试数据生成为一棵解空间树,通过搜索找到一条从根节点到叶节点的路径即一条测试数据。实验结果表明,该方法可以更好地生成覆盖面大且规模较小的测试用例集,实现对测试参数的两因素组合覆盖,从而解决了传统解空间树法由于不考虑参数间的制约关系而无法求得最简测试数据集或得到的数据集不完全的问题。将该数据生成方法应用于空间相机软件测试中提高了生成有效测试用例的效率和准确度,对测试起到了很好的指导作用。 展开更多
关键词 空间相机 软件测试 智能规划 因素组合覆盖 解空间树 待测软件系统(SUT)
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Human Settlement Analysis Based on Multi-temporal Remote Sensing Data: A Case Study of Xuzhou City, China 被引量:5
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作者 ZHU Jishuai TIAN Shufang +1 位作者 TAN Kun DU Peijun 《Chinese Geographical Science》 SCIE CSCD 2016年第3期389-400,共12页
To evaluate urban human settlement, we propose a human settlement environment development index(HSEDI) model by choosing vegetation coverage, land surface temperature, impervious surfaces, slope, wetness, and water co... To evaluate urban human settlement, we propose a human settlement environment development index(HSEDI) model by choosing vegetation coverage, land surface temperature, impervious surfaces, slope, wetness, and water condition as the evaluation factors. We applied the proposed model to Xuzhou City, Jiangsu Province, China. Landsat-5 Thematic Mapper(TM) images from 1998 to 2010 and digital elevation model(DEM) data with a 30-m resolution were used to calculate the values of the six evaluation factors. The HSEDI value in Xuzhou City was found to be between 2.24 and 8.10 from 1998 to 2010, and it was further divided into five levels, uninhabitable, moderately uninhabitable, generally inhabitable, moderately inhabitable, and inhabitable. The best HSEDI value was in 2007. The generally inhabitable region was about 100.98 km^2, covering 30.87% of the total area in 2007; the moderately inhabitable region was about 170.58 km2 covering 52.15% of the total area; the inhabitable region was about 32.03 km^2, covering 9.79% of the total area; the percentage of the uninhabitable region was zero; and that of the moderately uninhabitable region was very small, less than 1.00%. Moreover, we analyzed the habitability in the respect of spatial patterns and change detection. Results show that the degraded regions of habitability quality are mainly located in the urban fringe and the improved regions are mainly located in the main urban and rural areas. Reason for the degraded habitability quality is the rapid progress of urbanization. However, the increase in urban green spaces and the construction of the main urban area promoted the improved habitability quality. Besides, we further analyzed socio-economic and socio-demographic data to confirm the results of the habitability analysis. The results indicate that the human settlement in Xuzhou City is in a satisfactory condition, but some efforts should be made to control the possible uninhabitable and moderately uninhabitable regions, and to improve the quality of the generally inhabitable regions. 展开更多
关键词 habitability human settlement Landsat human settlement environment development index(HSEDI) model
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Effects of Vegetation Cover on Sum- mer Climate in China During 1982-2001
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作者 HABIB Aziz Salim CHEN Xiaoling GONG Jianya ZHANG Li 《Geo-Spatial Information Science》 2009年第1期41-45,共5页
In this paper, we apply lagged correlation analysis to study the effects of vegetation cover on the summer climate in different zones of China, using NOAA/AVHRR normalized difference vegetation index (NDVl) data dur... In this paper, we apply lagged correlation analysis to study the effects of vegetation cover on the summer climate in different zones of China, using NOAA/AVHRR normalized difference vegetation index (NDVl) data during the time period from 1982 to 2001 and climate data of 365 meteorological stations across China (precipitation from 1982 to 2001 and tempera- ture from 1982 to 1998). The results show that there are positive correlations between spring NDVl and summer climate (temperature and precipitation) in most zones of China; these suggest that, when the vegetation cover increases, the summer precipitation will increase, and the lagged correlations show a significant difference between zones. The stronger correlations between NDVl in previous season and summer climate occur in three zones (Mid-temperate zone, Warm-temperate zone and Plateau climate zone), and this implies that vegetation changes have more sensitive feedback effects on climate in the three zones in China. 展开更多
关键词 NOAA-AVHRR NDVI vegetation cover summer climate China
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