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Forest land use change at Trans-Boundary Laos-China Biodiversity Conservation Area 被引量:3
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作者 HEMMAVANH Chanhda YE Yanmei YOSHIDA A 《Journal of Geographical Sciences》 SCIE CSCD 2010年第6期889-898,共10页
This paper analyzed forest land use change in Trans-Boundary Laos-China Biodiversity Conservation Area which is called Namha National Biodiversity Conservation Areas (Namha NBCAs), with 1992 and 2002 TM (ETM). Bas... This paper analyzed forest land use change in Trans-Boundary Laos-China Biodiversity Conservation Area which is called Namha National Biodiversity Conservation Areas (Namha NBCAs), with 1992 and 2002 TM (ETM). Based on GIS and statistical methods, the intensity, state index of land use change and transfer matrix were used to study spatio-temporal land use change in the region. The results showed that the area of forest land decreased greatly, also the area of bamboo and grassland decreased. The other way round, the area of unstocked forest, slash and burn and rice paddy land increased. As a whole, the intensity of forest land change was higher, but others were lower. From the transfer matrix, most of the forest land changed into unstocked forest and urban area, some to slash and burn The grassland and bamboo were mainly transferred to forest and unstocked forest. The unstocked forest land mostly came from forest land and grassland. It was showed there were three main causes of the land use change namely: opium poppy cultivation, rubber plantation and also ecotourism activities and finally some policies were developed in order to address the land use change in the study areas. 展开更多
关键词 land use change rubber plantation opium poppy curivation Namha NBCAs Laos
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大素数域上椭圆曲线密码体制的软件实现 被引量:12
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作者 王晖 张方国 王育民 《西安电子科技大学学报》 EI CAS CSCD 北大核心 2002年第3期426-428,共3页
椭圆曲线密码体制已成为公钥密码研究的主流 .讨论了大素数域上椭圆曲线密码体制的软件实现问题 ,并以寻找的安全椭圆曲线为基础 ,在PentiumⅡ 35 0MHz微处理器上 ,利用标准C语言和汇编语言实现了椭圆曲线密码体制 .时间结果显示 ,2 2 4... 椭圆曲线密码体制已成为公钥密码研究的主流 .讨论了大素数域上椭圆曲线密码体制的软件实现问题 ,并以寻找的安全椭圆曲线为基础 ,在PentiumⅡ 35 0MHz微处理器上 ,利用标准C语言和汇编语言实现了椭圆曲线密码体制 .时间结果显示 ,2 2 4bit的椭圆曲线数字签名需要 1 6ms,验证需要 5 6ms. 展开更多
关键词 椭圆曲线 密码体制 大素数域 软件
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平纹栅格机织物的定形工艺
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作者 姚珍敏 《染整技术》 CAS 2009年第2期23-24,共2页
介绍一种平纹栅格机织物的定形工艺。从定形机设备选择到各种工艺因素的综合考虑,避免产品可能出现的质量问题。加工后的织物色泽均匀,亮丽,交叉点溶合性好,抗刺破性能强。
关键词 平纹栅格机织物 定形 经纬密 纬斜 纬弯
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四次系统内存在三次曲线极限环
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作者 王作全 李延忠 《长春光学精密机械学院学报》 1997年第3期55-58,共4页
本文证得一个四次系统,它以三次曲线的闭分支为极限环。本文说明三次曲线极限环上。果不存在于二次系统内[1],它可以存在于四次系统内。
关键词 三次代数曲线 极限环 四次系统
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