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基于边界规整的矩形PCB排样优化算法
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作者 姚远 李山武 潘勋勇 《计算机与数字工程》 2023年第8期1691-1696,1724,共7页
随着国内电子行业的快速发展,国内各厂商对PCB的需求量与日俱增,材料价格上涨较快,如何尽可能地提高母板板材利用率、子板规整率和类聚度已经成为各PCB制造厂商急需解决的问题,提出了一种基于边界规整的矩形PCB排样算法。算法基于对PCB... 随着国内电子行业的快速发展,国内各厂商对PCB的需求量与日俱增,材料价格上涨较快,如何尽可能地提高母板板材利用率、子板规整率和类聚度已经成为各PCB制造厂商急需解决的问题,提出了一种基于边界规整的矩形PCB排样算法。算法基于对PCB子板边界规整度和类聚度进行表征,与板材利用率进行加权构造出优化目标函数并使用差分进化算法对排样序列进行优化。实验表明,算法在PCB排样的板材利用率、子板规整率和类聚度的综合效果上有较大提高。 展开更多
关键词 PCB排样 边界规整 子板规整率 类聚度 差分进化
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热蒸发法制备一维ZnO晶须材料 被引量:2
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作者 张黎 《广东化工》 CAS 2014年第1期66-67,61,共3页
以陈化锌粉为锌源,利用热蒸发方法制得高纯度ZnO一维晶须材料,并对反应体系的工艺参数如氮气流量、反应温度、反应时间(保温时间)等因素对产物规整率、转化率及长径比的影响进行研究.利用SEM对产物形态进行表征.结果表明:以陈化锌粉... 以陈化锌粉为锌源,利用热蒸发方法制得高纯度ZnO一维晶须材料,并对反应体系的工艺参数如氮气流量、反应温度、反应时间(保温时间)等因素对产物规整率、转化率及长径比的影响进行研究.利用SEM对产物形态进行表征.结果表明:以陈化锌粉为锌源,当反应温度为1000~1100℃,通入氮气量为0.2 m3/h,保温时间为60 min时能制备出高规整率、高产率转化率及高长径比的ZnO一维纳米材料. 展开更多
关键词 一维ZnO晶须 制备 热蒸发法 规整率 转化 长径比
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一种仅使用呼吸信号检测非眼动睡眠的方法 被引量:1
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作者 李延军 仲崇发 +1 位作者 李琳 祝瑞云 《航天医学与医学工程》 CAS CSCD 北大核心 2015年第4期253-258,共6页
目的利用非眼动睡眠呼吸平稳的特征进行非眼动睡眠的检测。方法在呼吸信号时域定义幅度波动的变化率rA,在频域定义呼吸率的不规整度rf,以rA与rf为自变量建立线性分类判别方程。选择EDF睡眠扩展数据库的9位受试者(每人睡眠2晚)共18例睡... 目的利用非眼动睡眠呼吸平稳的特征进行非眼动睡眠的检测。方法在呼吸信号时域定义幅度波动的变化率rA,在频域定义呼吸率的不规整度rf,以rA与rf为自变量建立线性分类判别方程。选择EDF睡眠扩展数据库的9位受试者(每人睡眠2晚)共18例睡眠口鼻气流记录,其中9例记录用于模型训练,其余9例记录用于测试。结果个体化模型的训练错误率为20.0%,测试错误率为28.3%;通用模型的训练错误率为22.7%,测试错误率为30.8%。结论非眼动睡眠中,口鼻气流比较规整;觉醒与眼动睡眠中,呼吸不规整且波动较大。仅使用呼吸幅度变异性与呼吸率规整度可粗略对非眼动睡眠进行识别。 展开更多
关键词 自动睡眠分期 非眼动睡眠 呼吸信号 呼吸幅度变异性 呼吸规整 线性分类
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Adaptive Soft Frequency Reuse Scheme for In-building Dense Femtocell Networks 被引量:1
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作者 陈继明 王鹏 张杰 《China Communications》 SCIE CSCD 2013年第1期44-55,共12页
Femtocell networks have emerged as a key technology in residential, office building or hotspot deployments that can sig- nificantly fulfill high data demands in order to offioad indoor traffic from outdoor macro cells... Femtocell networks have emerged as a key technology in residential, office building or hotspot deployments that can sig- nificantly fulfill high data demands in order to offioad indoor traffic from outdoor macro cells. However, as one of the major challenges, inter-femtocell interference gets worse in 3D in-building scenarios because of the presence of numerous interfering sources and then needs to be considered in the early network planning phase. The indoor network planning and optimization tool suite, Ranplan Small- cell~, makes accurate prediction of indoor wireless RF signal propagation possible to guide actual indoor femtocell deployments. In this paper, a new adaptive soft frequency reuse scheme in the dense femtocell networks is proposed, where multiple dense femtocells are classified into a number of groups according to the dominant interference strength to others, then the minimum subchannels with different frequency reuse factors for these groups are determined and transmit powers of the group- ing sub-channels are adaptively adjusted based on the strength to mitigate the mutual inter- ference. Simulation results show the proposed scheme yields great performance gains in terms of the spectrum efficiency relative to the legacy soft frequency reuse and universal fre- quency reuse. 展开更多
关键词 in-building femtocell networks soft frequency reuse adaptive interferencecoordination
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DEA Analysis of Reverse Logistics of Supply Chain Integration Project Choice
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《Journal of Systems Science and Information》 2006年第2期323-330,共8页
Logistics has a good relationship with the economic utility of supply chain and the sustainable development of environment. It has been the considerable link of supply chain research. This paper analyzes and appraises... Logistics has a good relationship with the economic utility of supply chain and the sustainable development of environment. It has been the considerable link of supply chain research. This paper analyzes and appraises the effectivity of different supply chain integration projects and whether considers reverse logistics or not, by establishing DEA model of supply chain integration project that is on the basis of order and synthetically considered forward and reverse logistics, provides the growth efficiency model of input and output with preference supply chain integration project for the deci.qion.rn^le,~r 展开更多
关键词 reverse logistics supply chain DEA
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