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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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论新形势下高校机要秘书工作特点与素养要求 被引量:8
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作者 周梅芳 叶洪涛 《科教文汇》 2013年第2期184-184,共1页
高校机要秘书作为高校管理中一个特殊的工作岗位,在日常管理中发挥着重要的作用,特别是在信息高速发展的新形势下,给机要秘书工作带来了新的更高的要求。本文结合高校机要秘书的工作特性,阐述在新形势下高校机要秘书应具备的基本素质,... 高校机要秘书作为高校管理中一个特殊的工作岗位,在日常管理中发挥着重要的作用,特别是在信息高速发展的新形势下,给机要秘书工作带来了新的更高的要求。本文结合高校机要秘书的工作特性,阐述在新形势下高校机要秘书应具备的基本素质,全面提升自己的综合素养与业务技能。 展开更多
关键词 机要秘书 工作特点 素养
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超长工作面支架工作阻力分布及分区增阻特性研究 被引量:2
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作者 蔺星宇 徐刚 +2 位作者 高晓进 张震 刘前进 《煤炭科学技术》 CAS CSCD 北大核心 2023年第4期11-20,共10页
综采工作面倾向长度的增加,对顶板破断及应力演化产生的影响效应是复杂的,导致工作面支架支护特性存在分区差异。为深入理解超长工作面支架与围岩相互作用关系,以小保当煤矿450 m超长工作面为工程背景,构建弹性基础岩梁力学模型,运用数... 综采工作面倾向长度的增加,对顶板破断及应力演化产生的影响效应是复杂的,导致工作面支架支护特性存在分区差异。为深入理解超长工作面支架与围岩相互作用关系,以小保当煤矿450 m超长工作面为工程背景,构建弹性基础岩梁力学模型,运用数理统计及均化循环分析方法,对工作面支架实测数据开展循环末阻力、工作阻力分布频率、支架增阻特性分析,明晰不同面长工作面倾向方向顶板运动及支架工作阻力分布特征,探究超长工作面支架倾向分区内支架增阻特性。研究结果表明:工作面倾向长度增加,导致两巷煤体对中部顶板的支承减弱,中部峰值区域向两巷移近,超长工作面支架工作阻力分布趋势呈M型三峰值分布;超长工作面上部、中部、下部三区域支架呈对数型增阻时,其均化曲线仍为对数函数,表现为先急增阻后趋于平缓,此种支架增阻情况反映了来压期间工作面顶板由快速下沉逐渐变为缓慢下沉;呈对数-指数型增阻时,中上部区域支架增阻均化曲线为对数函数,中部及中下部均化曲线为对数-指数型复合函数,表现出先急增阻然后趋于平缓最后急增阻的特征;当支架工作循环时间超过一定值,对数-指数复合增阻型支架会急速增阻,不利于顶板控制,通过优化工作面割煤速度,降低支架工作循环时间,可减小支架增阻量,避免高阻力状态下支架再次瞬时增阻,提升工作面支架支护效果。 展开更多
关键词 超长工作面 均化循环 支架工作阻力 支架增阻特性 分区特征
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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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高速公路半幅封闭施工区交通特性与交通冲突特性研究 被引量:34
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作者 孟祥海 郑来 +2 位作者 毕海峰 关志强 徐汉清 《中国公路学报》 EI CAS CSCD 北大核心 2013年第2期140-146,共7页
对双向四车道高速公路半幅封闭施工区的交通特性和交通冲突特性开展研究。以交通流参数调查和交通冲突调查为基础,应用统计分析方法,研究了施工区上游过渡段车辆的排队特征,标定了描述车头时距分布的爱尔朗模型;分析了施工区各组成区段... 对双向四车道高速公路半幅封闭施工区的交通特性和交通冲突特性开展研究。以交通流参数调查和交通冲突调查为基础,应用统计分析方法,研究了施工区上游过渡段车辆的排队特征,标定了描述车头时距分布的爱尔朗模型;分析了施工区各组成区段的速度分布特征,确定了基于统计分布原理的各区段限速范围;总结了施工区交通冲突的种类,给出了基于距离碰撞时间的追尾冲突严重程度判别方法,建立了基于负二项分布的追尾冲突预测模型。最后,应用VISSIM软件开展了施工区交通仿真试验。结果表明:基于车辆排队特征所确定的施工区上游过渡段合理长度应在45~70m之间;施工区各区段的限速值应根据交通量设定;在相同交通量水平下当限速值高于50km·h-1时,交通冲突数量会随着限速值提高而显著增加。 展开更多
关键词 交通工程 高速公路 交通仿真 交通冲突 交通特性 半幅封闭施工区
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