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半固着磨具“陷阱”效应的颗粒流模拟 被引量:9
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作者 袁巨龙 王志伟 +1 位作者 钱苗 洪滔 《中国机械工程》 EI CAS CSCD 北大核心 2009年第6期714-718,共5页
利用PFC软件建立了半固着磨具颗粒流模型,磨具中结合剂对磨粒的粘结作用由平行连接行为描述。模型参数通过半固着磨具试样的压缩比实验获得。考虑单颗大颗粒的"陷阱"效应,以量纲一的大颗粒陷入磨具的深度及对工件的法向载荷... 利用PFC软件建立了半固着磨具颗粒流模型,磨具中结合剂对磨粒的粘结作用由平行连接行为描述。模型参数通过半固着磨具试样的压缩比实验获得。考虑单颗大颗粒的"陷阱"效应,以量纲一的大颗粒陷入磨具的深度及对工件的法向载荷为指标,对半固着磨具的"陷阱"效应进行了仿真。讨论了磨具结合强度、加工载荷、大颗粒尺寸对"陷阱"效应的影响,发现磨具结合强度低、加工载荷大和大颗粒尺寸小将有利于"陷阱"效应的发挥。 展开更多
关键词 半固着磨具 “陷阱”效应 大颗粒 颗粒流方法
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半固着磨具“陷阱”效应影响因素分析 被引量:4
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作者 赵萍 王志伟 袁巨龙 《中国机械工程》 EI CAS CSCD 北大核心 2011年第20期2399-2403,共5页
以抛光后无表面损伤的单晶硅片为试件,以表面粗糙度Ra为指标,对半固着磨具的"陷阱"效应进行试验分析,讨论大颗粒浓度及尺寸、磨具硬度、加工载荷、磨具转速对"陷阱"效应的影响。研究结果表明:对一定尺寸的大颗粒,... 以抛光后无表面损伤的单晶硅片为试件,以表面粗糙度Ra为指标,对半固着磨具的"陷阱"效应进行试验分析,讨论大颗粒浓度及尺寸、磨具硬度、加工载荷、磨具转速对"陷阱"效应的影响。研究结果表明:对一定尺寸的大颗粒,当大颗粒数量不超过临界值时,大颗粒可全部陷入,"陷阱"效应发挥;当大颗粒尺寸较大、磨具硬度较高、加工载荷较大时,不利于"陷阱"效应发挥。 展开更多
关键词 半固着磨具 “陷阱”效应 大颗粒 表面粗糙度
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半固着磨粒加工工艺参数对“陷阱”效应影响的离散元模拟
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作者 袁巨龙 钱苗 +2 位作者 王志伟 汤科锋 洪涛 《现代制造工程》 CSCD 北大核心 2009年第1期1-5,共5页
半固着磨粒加工以"陷阱"效应来降低加工质量和效率对磨粒尺寸分布均匀程度的敏感性,可提高精密、超精密加工的生产效率。对半固着磨具的"陷阱"效应进行离散元模拟,选取多种不同粒径大颗粒,分析加工载荷、工件与磨... 半固着磨粒加工以"陷阱"效应来降低加工质量和效率对磨粒尺寸分布均匀程度的敏感性,可提高精密、超精密加工的生产效率。对半固着磨具的"陷阱"效应进行离散元模拟,选取多种不同粒径大颗粒,分析加工载荷、工件与磨具的相对速度,以及工件摩擦因数三个加工工艺参数对"陷阱"效应的影响。仿真结果表明:加工载荷越大,半固着磨具"陷阱"效应发挥越好;而工件与磨具的相对速度和工件摩擦因数对半固着磨具"陷阱"效应影响不大;大颗粒尺寸越接近磨具中磨粒的尺寸,半固着磨具的"陷阱"效应发挥越好。 展开更多
关键词 半固着磨具 “陷阱”效应 离散单元法
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Degradation of P-MOSFETs Under Off-State Stress
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作者 杨存宇 王子欧 +1 位作者 谭长华 许铭真 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2001年第1期25-30,共6页
The hot carrier effects under off- state stress m ode( Vgs=0 ,Vds<0 ) have been investigated on9nm P- MOSFETs with channel length varying from1.0 2 5 μm to0 .5 2 5 μm.Both on- and off- state currents are discuss... The hot carrier effects under off- state stress m ode( Vgs=0 ,Vds<0 ) have been investigated on9nm P- MOSFETs with channel length varying from1.0 2 5 μm to0 .5 2 5 μm.Both on- and off- state currents are discussed. It is found that the off- state leakage current decreases after a higher voltage stressing,which is induced by the charge injection occurred close to the drain junction.However,the leakage current increases after a lower voltage stressing because of the newly generated interface traps.It is also found that the on state saturation current and threshold voltage degrade significantly with the stress tim e,which we believe is due to the charges injected near the gate- drain overlapping region and/ or the stress- induced interface trap generation.The degradation of Idsatcan be ex- pressed as a function of the product of the gate current( Ig) and the num ber of charges injected into the gate oxide ( Qinj) in a simple power law.Finally,a lifetime prediction model based on the degradation of Idsatis proposed. 展开更多
关键词 off- state stress GIDL HCI interface traps
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Highly efficient organic solar cells enabled by a porous ZnO/PEIE electron transport layer with enhanced light trapping 被引量:2
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作者 Shenya Qu Jiangsheng Yu +4 位作者 Jinru Cao Xin Liu Hongtao Wang Shun Guang Weihua Tang 《Science China Materials》 SCIE EI CAS CSCD 2021年第4期808-819,共12页
In this study,a porous inorganic/organic(ZnO/PEIE,where PEIE is polyethylenimine ethoxylated)(P-ZnO)hybrid material has been developed and adopted in the inverted organic solar cells(OSCs).The P-ZnO serving as the ele... In this study,a porous inorganic/organic(ZnO/PEIE,where PEIE is polyethylenimine ethoxylated)(P-ZnO)hybrid material has been developed and adopted in the inverted organic solar cells(OSCs).The P-ZnO serving as the electron transport layer(ETL)not only presents an ameliorative work function,but also forms the cratered surface with increased ohmic contact area,revealing suppressed charge recombination and enhanced charge extraction in devices.Particularly,P-ZnO-based OSCs show improved light trapping in the active layer compared with ZnO-based ones.The universality of P-ZnO serving as ETL for efficient OSCs is verified on three photovoltaic systems of PBDB-T/DTPPSe-2 F,PM6/Y6,and PTB7-Th/PC_(71)BM.The enhancements of 8%in power conversion efficiency(PCE)can be achieved in the state-of-the-art OSCs based on PBDB-T/DTPPSe-2F,PM6/Y6,and PTB7-Th/PC_(71)BM,delivering PCEs of 14.78%,16.57%,and 9.85%,respectively.Furthermore,a promising PCE of14.13%under air-processed condition can be achieved for PZnO/PBDB-T/DTPPSe-2F-based OSC,which is among the highest efficiencies reported for air-processed OSCs in the literature.And the P-ZnO/PBDB-T/DTPPSe-2F-based device also presents superior long-term storage stability whether in nitrogen or ambient air-condition without encapsulation,which can maintain over 85%of its initial efficiency.Our results demonstrate the great potential of the porous hybrid PZnO as ETL for constructing high-performance and air-stable OSCs. 展开更多
关键词 light trapping electron transport layer porous structure STABILITY organic solar cells
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