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Upshot of Sprawl Incidence on Pattern of Land Use Changes and Building Physiognomies in Akure Region, Nigeria
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作者 Owoeye J.O. 《Journal of Geographical Research》 2020年第4期36-44,共9页
This study investigates the upshot of sprawl incidence on pattern of land use changes and building physiognomies in Akure and its environs.Using social survey research method(SSRM)to investigate the upshot,data were g... This study investigates the upshot of sprawl incidence on pattern of land use changes and building physiognomies in Akure and its environs.Using social survey research method(SSRM)to investigate the upshot,data were gathered via structured questionnaires on selected households in the region,involving Akure municipal and eight contiguous communities.Basically,the survey method involves interview,personal observation and photo-snaps to elucidate existing situation in the region.Average households’population in Akure municipal was estimated at 95,232 while 14,794 was estimated in the selected eight contiguous communities.From this,a sample of 1%was systematically selected,which amounted to 1100 sampled households.Findings show regular massive inflow of people into the city due to unguided expansions that have serious sway on land use determinant in the city and its contiguous communities.It also has significant influence on variation in building arrangements and facility distribution across the region.To mitigate this,the study advocates proactive efforts of stakeholders in urban management to employing inventive measures over private and public lands in logical manners.It also suggests the espousal of regional development programs to checkmate the rate of peoples’incursion into Akure,being the state capital.Local government headquarters and other major towns in the region should be reinforced with functional basic facilities to curtail the excessive influx into the city. 展开更多
关键词 upshot Sprawl incidence Land use change Building physiognomies Unguided expansion
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螺旋线型水介质长脉冲形成线的设计与改进 被引量:8
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作者 刘振祥 张建德 《强激光与粒子束》 EI CAS CSCD 北大核心 2006年第12期2078-2081,共4页
设计了长2.2 m、直径0.40 m、工作电压400 kV、脉宽200 ns的螺旋线型水介质脉冲形成线加速器,并进行了实验研究。为消除输出脉冲的前沿上冲和后沿拖尾现象,分析了脉冲形成线中的连接段与螺旋线阻抗的不匹配对输出波形的影响。用高分子... 设计了长2.2 m、直径0.40 m、工作电压400 kV、脉宽200 ns的螺旋线型水介质脉冲形成线加速器,并进行了实验研究。为消除输出脉冲的前沿上冲和后沿拖尾现象,分析了脉冲形成线中的连接段与螺旋线阻抗的不匹配对输出波形的影响。用高分子材料加工了内径为10 cm,外径为18 cm的高阻抗环套在螺旋线与主开关之间的连接段上,使这一段的阻抗与螺旋线阻抗接近,并使其电长度减小,消除了前沿上冲,减弱了后沿拖尾,得到了上升沿约18 ns、下降沿约40 ns的近似方波高电压脉冲输出。 展开更多
关键词 长脉冲 螺旋线型脉冲形成线 水介质 上冲 拖尾
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螺旋线型脉冲形成线匝间击穿与输出波形的研究 被引量:1
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作者 刘振祥 张建德 +3 位作者 刘金亮 杨建华 冯加怀 罗玲 《强激光与粒子束》 EI CAS CSCD 北大核心 2007年第1期160-164,共5页
针对螺旋线型脉冲形成线放电过程的匝间击穿问题,采用数值模拟的方法研究了影响螺旋线上轴向电场的因素,模拟结果表明:螺旋线的螺旋角越大、开关的上升沿越小、负载的阻值越小则越容易造成匝间击穿;针对输出波形的前沿上冲和下凹问题,... 针对螺旋线型脉冲形成线放电过程的匝间击穿问题,采用数值模拟的方法研究了影响螺旋线上轴向电场的因素,模拟结果表明:螺旋线的螺旋角越大、开关的上升沿越小、负载的阻值越小则越容易造成匝间击穿;针对输出波形的前沿上冲和下凹问题,通过数值模拟和实验方法研究了加速器内阻抗不匹配段对输出波形的影响,结果表明:改变螺旋线与开关之间连接段的阻抗以及开关和二极管之间过渡段的阻抗,使之接近于螺旋线阻抗,并使电长度减小,可以消除波形的前沿上冲和下凹,得到近似方波的高电压脉冲输出。 展开更多
关键词 螺旋线型脉冲形成线 匝间击穿 轴向电场 前沿上冲 下凹
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