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Effects of Planting and Irrigation Patterns on Water Consumption Characteristics and Dry Matter Production in Winter Wheat
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作者 董浩 朱国梁 +1 位作者 毕军 陈靖 《Agricultural Science & Technology》 CAS 2016年第7期1585-1591,共7页
[Objective] This study aimed to investigate the effects of different planting and irrigation patterns on water consumption characteristics and dry matter produc- tion and allocation of winter wheat. [Method] With high... [Objective] This study aimed to investigate the effects of different planting and irrigation patterns on water consumption characteristics and dry matter produc- tion and allocation of winter wheat. [Method] With high-yield winter wheat cultivar Jimai 22 as the experimental material, field experiment was conducted during 2008- 2010. A total of 3 planting patterns were designed, uniform row, wide-narrow row and furrow. Under each planting pattern, total four irrigation patterns were designed, no irrigation (Wo), irrigation at jointing state (Wl), irrigation at jointing and anthesis stages (W2) and irrigation at jointing, anthesis and milking stages (W3), and the irri- gation amount per treatment was all 60 mm. [Result] Under the three planting pat- terns, with the increased irrigation amount, the total water consumption of the exper- imental field increased; the proportion of irrigation in the total water consumption in- creased, and that of soil water consumption in the total water consumption de- creased significantly. Compared with W0 treatment, various irrigation treatments sig- nificantly increased the post-anthesis dry matter accumulation in wheat plants; with the increased irrigation amount, the grain yield under the three planting patterns all increased, while the water use efficiency (WUE) decreased. Under the same irriga- tion conditions, compared with other two planting patterns, furrow planting increased the total water consumption of the experimental field, increased the proportion of soil water consumption in the total water consumption, and improved the WUE and wheat grain yield. [Conclusion] Under the experimental conditions, considering both wheat grain yield and WUE, furrow planting with moderately deficit irrigation at joint- ing and anthesis stages is more suitable for the winter wheat production in North China Plain. 展开更多
关键词 Winter wheat IRRIGATION Planting pattern Water consumption character- istics Dry matter accumulation and allocation
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Analysis of Land Use Characteristics in Mountainous Areas in Yunnan Province Based on Second National Land Survey 被引量:2
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作者 芦艳艳 杨子生 《Agricultural Science & Technology》 CAS 2014年第9期1438-1440,共3页
Abstract Based on Second National Land Survey during 2007-2009 and land use type survey in ftatland areas, status quo of land use in mountainous areas in Yun- nan was measured, and analysis was made on land use in mou... Abstract Based on Second National Land Survey during 2007-2009 and land use type survey in ftatland areas, status quo of land use in mountainous areas in Yun- nan was measured, and analysis was made on land use in mountainous areas in terms of land use structure, degree and development potential, providing references for rational use of land in mountainous areas in Yunnan. 展开更多
关键词 Second national land survey Mountainous areas Land use character- istics Yunnan Province
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青藏高原荒漠化遥感信息提取及演变分析 被引量:18
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作者 张佩民 张振德 +3 位作者 李晓琴 王毅 余江宽 黄永芳 《干旱区地理》 CSCD 北大核心 2006年第5期710-717,共8页
在青藏高原258万km2范围内,首次利用Landsat 7 ETM和Landsat3 MSS图像,对整个高原内的砂砾质荒漠化土地、盐碱质荒漠化土地和耕地、草地、林地、沼泽地、地表水体、基岩等土地类型的15种环境因子进行遥感信息提取,结合地面验证,查清了1... 在青藏高原258万km2范围内,首次利用Landsat 7 ETM和Landsat3 MSS图像,对整个高原内的砂砾质荒漠化土地、盐碱质荒漠化土地和耕地、草地、林地、沼泽地、地表水体、基岩等土地类型的15种环境因子进行遥感信息提取,结合地面验证,查清了15种环境因子在20世纪70年代和21世纪初两个时期的实际分布面积。对荒漠化土地的遥感图像特征和演变规律进行了综合分析。指出了青藏高原目前在生态地质环境方面存在的突出问题主要是荒漠化程度严重、植被退化严重、水土流失严重、资源开发无序严重和水资源短缺等问题。 展开更多
关键词 荒漠化 遥感信息提取 荒漠化演变 图像特征 演变规律
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水轮发电机局部放电在线监测中的脉冲识别方法 被引量:13
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作者 万元 李朝晖 +1 位作者 薛松 罗曼 《高电压技术》 EI CAS CSCD 北大核心 2009年第9期2169-2175,共7页
在水轮发电机局部放电在线监测中,脉冲识别是关键技术之一。在对现场信号进行离散谱干扰抑制及单脉冲边沿确定等预处理的基础上,为实现脉冲识别,采用了基于自适应聚类及三维谱图与基于时频联合特征提取的两种脉冲识别方法。根据实际应... 在水轮发电机局部放电在线监测中,脉冲识别是关键技术之一。在对现场信号进行离散谱干扰抑制及单脉冲边沿确定等预处理的基础上,为实现脉冲识别,采用了基于自适应聚类及三维谱图与基于时频联合特征提取的两种脉冲识别方法。根据实际应用的经验,改进了自适应聚类算法。提取脉冲的等效时间宽度、等效振荡速度作为时域特征,利用小波变换计算脉冲的频域特征,并将二维图形的统计参数应用于脉冲识别。在介绍两种方法基本原理的基础上对其进行比较,结果表明,基于时频域联合特征提取的脉冲识别方法为现场应用的最佳方案,它保证了局部放电脉冲的有效识别,同时为实现水轮发电机的其它电磁冲击监测提供了一种较好的解决方法。 展开更多
关键词 水轮发电机 局部放电 在线监测 脉冲识别 自适应聚类 特征提取
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基于非抽样提升小波包的机械隐含故障诊断 被引量:2
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作者 段礼祥 刘亚峰 +2 位作者 张庆春 唐瑜 王学东 《石油机械》 北大核心 2012年第10期76-80,共5页
传统的提升变换要进行下采样运算,容易产生频率混叠。为此,提出用非抽样提升算法实现小波包分解,以消除频率混叠,达到提取信号中微弱冲击成分的目的。提升小波分解以提升方案为基础,用多项式插值求取小波系数,然后构造尺度函数并求取信... 传统的提升变换要进行下采样运算,容易产生频率混叠。为此,提出用非抽样提升算法实现小波包分解,以消除频率混叠,达到提取信号中微弱冲击成分的目的。提升小波分解以提升方案为基础,用多项式插值求取小波系数,然后构造尺度函数并求取信号中的低频系数。由于每一层系数的长度等于原始信号的长度,所以不存在频率混叠,同时分解后的信号凸显了微弱故障特征信息。用该方法对电动机轴承振动信号进行提升变换处理,完整地提取出了电动机转轴与轴瓦碰磨产生的微弱冲击信号,诊断出了机械隐含故障。 展开更多
关键词 故障诊断 非抽样提升小波包 提升变换 隐含故障 微弱信号 特征提取
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基于Beamlet变换的断层识别与线性提取 被引量:2
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作者 荆智辉 张世晖 李强 《物探与化探》 CAS CSCD 2013年第3期543-546,共4页
Beamlet变换在提取图像线性特征方面效果明显。对于三维地震解释,可将地震相干切片视为图像,切片上断层可视为线性信息,利用Beamlet变换可对切片上的断层进行识别和线性提取。笔者首先介绍了Beamlet变换基本原理,以及其在含噪图像线性... Beamlet变换在提取图像线性特征方面效果明显。对于三维地震解释,可将地震相干切片视为图像,切片上断层可视为线性信息,利用Beamlet变换可对切片上的断层进行识别和线性提取。笔者首先介绍了Beamlet变换基本原理,以及其在含噪图像线性特征提取中的优势,然后利用Beamlet变换对四川元坝地区的三维地震相干切片进行断层识别和线性特征提取,并对断层线性信息进行统计分析。结果表明,该方法对于小断层和裂隙发育带的解释具有明显优势。 展开更多
关键词 BEAMLET变换 线特征提取 断层识别和提取 断层走向和延伸长度统计
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DYNAMIC CHARACTERISTICS IN INCOMPRESSIBLE HYPERELASTIC CYLINDRICAL MEMBRANES 被引量:2
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作者 Datian Niu Xuegang Yuan +1 位作者 Changjun Cheng Jiusheng Ren 《Acta Mechanica Solida Sinica》 SCIE EI 2010年第5期420-427,共8页
In this paper, the dynamic characteristics are examined for a cylindrical membrane composed of a transversely isotropic incompressible hyperelastic material under an applied uniform radial constant pressure at its inn... In this paper, the dynamic characteristics are examined for a cylindrical membrane composed of a transversely isotropic incompressible hyperelastic material under an applied uniform radial constant pressure at its inner surface. A second-order nonlinear ordinary differential equation that approximately describes the radial oscillation of the inner surface of the membrane with respect to time is obtained. Some interesting conclusions are proposed for different materials, such as the neo-Hookean material, the Mooney-Rivlin material and the Rivlin-Saunders material. Firstly, the bifurcation conditions depending on the material parameters and the pressure loads are determined. Secondly, the conditions of periodic motion are presented in detail for membranes composed of different materials. Meanwhile, numerical simulations are also provided. 展开更多
关键词 incompressible hyperelastic material cylindrical membrane dynamical character- istic nonlinear periodic oscillation
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