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不同类型层压机对PCB涨缩和介厚均匀性的影响 被引量:1
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作者 罗永红 武瑞黄 黄剑 《电子工艺技术》 2015年第3期141-145,157,共6页
随着PCB技术的迅猛发展,其层数不断增加,内层芯板厚度越来越薄,这对制造过程中涨缩和介厚均匀性的控制提出了更高的要求。由于B系统和C系统两种层压机加热和加压方式的不同,使用不同的材料对这两种层压机试验板的涨缩均匀性和介厚均匀... 随着PCB技术的迅猛发展,其层数不断增加,内层芯板厚度越来越薄,这对制造过程中涨缩和介厚均匀性的控制提出了更高的要求。由于B系统和C系统两种层压机加热和加压方式的不同,使用不同的材料对这两种层压机试验板的涨缩均匀性和介厚均匀性进行了评估。结果表明,用C系统层压机生产的试验板的尺寸变化比B的小(特别是在长边方向)并且均匀性更好;用两种层压机生产的试验板介厚的极差和标准偏差非常接近,其介厚的差距不大。 展开更多
关键词 PCB 层压机 涨缩 介厚均匀性
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系统级封装天线电路板介厚均匀性研究
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作者 谢帮文 张铭辉 杨广丰 《印制电路信息》 2022年第S01期229-237,共9页
系统级封装天线电路板对射频的控制要求很严苛,射频传输效果直接影响天线板的信号功能。而针对射频信号低损耗方面的需求,一般选用超高树脂含量的半固化片,如1086RC71%。在PCB的制作过程中,射频对介厚均匀性的要求非常高。文章通过对压... 系统级封装天线电路板对射频的控制要求很严苛,射频传输效果直接影响天线板的信号功能。而针对射频信号低损耗方面的需求,一般选用超高树脂含量的半固化片,如1086RC71%。在PCB的制作过程中,射频对介厚均匀性的要求非常高。文章通过对压合后的介厚均匀性进行研究对射频的影响,制定不同的优化板边设计、调整树脂流动度(RF)、及优化生产方式等一系列测试方案进行验证对射频影响有改善。为后续天线板设计制作提供参考。 展开更多
关键词 射频 板边假铜设计 介厚均匀性 树脂流动度
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高速半固化片压合介质厚度的优化研究
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作者 傅宝林 杜红兵 纪成光 《印制电路信息》 2018年第A02期236-245,共10页
文章研究了不同压合过程控制和不同图形设计对介厚的影响,纠正了不同类型不同张数高速半固化片的压合介质厚度,以及多张高速半固化片压合的介质厚度值;同时通过对比分析不同理论介厚值与实际介厚值的差值,得出了采用纠正后的理论介... 文章研究了不同压合过程控制和不同图形设计对介厚的影响,纠正了不同类型不同张数高速半固化片的压合介质厚度,以及多张高速半固化片压合的介质厚度值;同时通过对比分析不同理论介厚值与实际介厚值的差值,得出了采用纠正后的理论介厚值更接近于实际压合的介厚值,设定的介厚值更精确。 展开更多
关键词 纠正的 高速半固化片 图形设计 实际介厚
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分析影响PCB阻抗主要因素及影响差异对比 被引量:6
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作者 徐越 范红 金浩 《印制电路信息》 2021年第S02期1-10,共10页
通过对不同介质厚度、线宽、材料介电常数DK、铜厚、油墨厚度等影响因素研究,分析影响PCB阻抗的主要因素和阻抗影响不同程度,为高精度阻抗管控提供参考。
关键词 高精度阻抗 介厚 线宽 材料电常数D_(K) 防焊油墨
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高速PCB插损影响因子研究 被引量:4
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作者 雷璐娟 雷川 +2 位作者 李金鸿 徐竟成 涂逊 《印制电路信息》 2022年第S01期28-34,共7页
随着高速电路的传输速率不断提升,电子产品不断微小化、精密化、高速化,使得电路的集成度越来越高。PCB不仅要完成各种原器件的线路连接,更要考虑高密高速带来的信号完整性问题。高速互连中首要的信号完整性问题是传输线损耗,损耗会引... 随着高速电路的传输速率不断提升,电子产品不断微小化、精密化、高速化,使得电路的集成度越来越高。PCB不仅要完成各种原器件的线路连接,更要考虑高密高速带来的信号完整性问题。高速互连中首要的信号完整性问题是传输线损耗,损耗会引起信号上升沿的退化和幅度的衰减,导致严重的信号失真。通过各种仿真软件虽然能够仿真出各影响因子对损耗的理论影响趋势,但实际生产中往往与仿真结果存在一定偏差。文章仅针对参考层厚度、线宽、线距、PCB排版时图形旋转角度及背钻Stub长度对插入损耗的影响进行实验研究,并得出较为准确的设计区间,为高速信号传输的选材及设计优化提供依据,使实际生产结果与理论模拟更为接近。 展开更多
关键词 高速PCB 插耗 旋转角度 差分Skew 玻纤效应 背钻Stub 线宽 线距 介厚
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阻抗±5%公差影响因素分析与探讨 被引量:2
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作者 廖辉 《印制电路信息》 2014年第4期82-87,共6页
如何保证各种信号(特别是高速信号)完整性,如何保证信号传输质量,PCB板控制信号线的特征阻抗匹配成为关键,不严格的阻抗控制,将引发信号传输的失真何信号的反射,导致设计的失败,本文主要针对影响阻抗控制关键因素进行初步分析和研究,为... 如何保证各种信号(特别是高速信号)完整性,如何保证信号传输质量,PCB板控制信号线的特征阻抗匹配成为关键,不严格的阻抗控制,将引发信号传输的失真何信号的反射,导致设计的失败,本文主要针对影响阻抗控制关键因素进行初步分析和研究,为保证信号传输的稳定性,提供控制规范和参考;为业界实现阻抗控制提供一定的参考何借鉴。 展开更多
关键词 内层线宽 外层线宽 层压半固化片介厚 油墨 阻抗±5%
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印制电路板可制造性设计综述
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作者 孟凡义 《印制电路信息》 2017年第A01期15-20,共6页
印制电路板良好的可制造性设计,对工艺流程简化、成本降低、品质改善及效率提升至关重要。文章从前端客户设计到印制电路板工厂内部资料处理,综述热管理、超薄介厚、微小孔、精细线/距、最终表面涂覆工艺等相关可制造性设计内容,供... 印制电路板良好的可制造性设计,对工艺流程简化、成本降低、品质改善及效率提升至关重要。文章从前端客户设计到印制电路板工厂内部资料处理,综述热管理、超薄介厚、微小孔、精细线/距、最终表面涂覆工艺等相关可制造性设计内容,供印制电路板设计者及加工者参考,以期望获得较佳的可制造性设计,实现需求者与制造者双赢。 展开更多
关键词 可制造性设计 热管理 超薄介厚 微小孔 精细线/距 最终表面涂覆工艺
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A High Performance Sub-100nm Nitride/Oxynitride Stack Gate Dielectric CMOS Device with Refractory W/TiN Metal Gates
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作者 钟兴华 周华杰 +1 位作者 林钢 徐秋霞 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第3期448-453,共6页
By complementing the equivalent oxide thickness (EOT) of a 1.7nm nitride/oxynitride (N/O) stack gate dielectric (EOT- 1.7nm) with a W/TiN metal gate electrode,metal gate CMOS devices with sub-100nm gate length a... By complementing the equivalent oxide thickness (EOT) of a 1.7nm nitride/oxynitride (N/O) stack gate dielectric (EOT- 1.7nm) with a W/TiN metal gate electrode,metal gate CMOS devices with sub-100nm gate length are fabricated in China for the first time. The key technologies adopted to restrain SCE and to improve drive ability include a 1.7nm N/O stack gate dielectric, non-CMP planarization technology, a T-type refractory W/TiN metal stack gate electrode, and a novel super steep retrograde channel doping using heavy ion implantation and a double sidewall scheme. Using these optimized key technologies, high performance 95nm metal gate CMOS devices with excellent SCE and good driving ability are fabricated. Under power supply voltages of VDS ± 1.5V and VGS± 1.8V,drive currents of 679μA/μm for nMOS and - 327μA/μm for pMOS are obtained. A subthreshold slope of 84.46mV/dec, DIBL of 34.76mV/V, and Vth of 0.26V for nMOS, and a subthreshold slope of 107.4mV/dec,DIBL of 54.46mV/V, and Vth of 0.27V for pMOS are achieved. These results show that the combined technology has indeed thoroughly eliminated the boron penetration phenomenon and polysilicon depletion effect ,effectively reduced gate tunneling leakage, and improved device reliability. 展开更多
关键词 equivalent oxide thickness nitride/oxynitride gate dielectric stack W/TiN metal gate non-CMP planarization
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Cardiovascular risk after orthotopic liver transplantation, a review of the literature and preliminary results of a prospective study 被引量:4
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作者 Giuseppina Pisano Anna L Fracanzani +2 位作者 Lucio Caccamo Maria F Donato Silvia Fargion 《World Journal of Gastroenterology》 SCIE CAS 2016年第40期8869-8882,共14页
Improved surgical techniques and greater efficacy of new anti-rejection drugs have significantly improved the survival of patients undergoing orthotopic liver transplantation(OLT). This has led to an increased inciden... Improved surgical techniques and greater efficacy of new anti-rejection drugs have significantly improved the survival of patients undergoing orthotopic liver transplantation(OLT). This has led to an increased incidence of metabolic disorders as well as cardiovascular and cerebrovascular diseases as causes of morbidity and mortality in OLT patients. In the last decade, several studies have examined which predisposing factors lead to increased cardiovascular risk(i.e., age, ethnicity, diabetes, NASH, atrial fibrillation, and some echocardiographic parameters) as well as which factors after OLT(i.e., weight gain, metabolic syndrome, immunosuppressive therapy, and renal failure) are linked to increased cardiovascular mortality. However, currently, there are no available data that evaluate the development of atherosclerotic damage after OLT. The awareness of high cardiovascular risk after OLT has not only lead to the definition of new but generally not accepted screening of high risk patients before transplantation, but also to the need for careful patient follow up and treatment to control metabolic and cardiovascular pathologies after transplant. Prospective studies are needed to better define the predisposing factors for recurrence and de novo occurrence of metabolic alterations responsible for cardiovascular damage after OLT. Moreover, such studies will help to identify the timing of disease progression and damage,which in turn may help to prevent morbidity and mortality for cardiovascular diseases. Our preliminary results show early occurrence of atherosclerotic damage, which is already present a few weeks following OLT, suggesting that specific, patient-tailored therapies should be started immediately post OLT. 展开更多
关键词 Orthotopic liver transplant Cardiovascular risk ATHEROSCLEROSIS Non-alcoholic fatty liver disease Intima-media thickness Epicardial fat thickness Diastolic dysfunction
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Melting heat transfer with radiative effects and homogeneous–heterogeneous reaction in thermally stratified stagnation flow embedded in porous medium 被引量:4
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作者 M.JAVED M.FAROOQ +1 位作者 S.AHMAD Aisha ANJUM 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第11期2701-2711,共11页
The present article deals with thermally stratified stagnation-point flow saturated in porous medium on surface of variable thickness along with more convincing and reliable surface condition termed as melting heat tr... The present article deals with thermally stratified stagnation-point flow saturated in porous medium on surface of variable thickness along with more convincing and reliable surface condition termed as melting heat transfer.Homogeneous–heterogeneous reaction and radiative effects have been further taken into account to reconnoiterproperties of heat transfer.Melting heat transfer and phenomenon of homogeneous–heterogeneous reaction have engrossed widespread utilization in purification of metals,welding process,electroslag melting,biochemical systems,catalysis and several industrial developments.Suitable transformations are utilized to attain a scheme of ordinary differential equations possessing exceedingly nonlinear nature.Homotopic process is employed to develop convergent solutions of the resulting problem.Discussion regarding velocity,thermal field and concentration distribution for several involved parameters is pivotal part.Graphical behaviors of skin friction coefficient and Nusselt number are also portrayed.Concentration of the reactants is found to depreciate as a result of strength of both heterogeneous and homogeneous reaction parameters.With existence of melting phenomenon,declining attitude of fluid temperature is observed for higher radiation parameter. 展开更多
关键词 melting heat transfer porous medium stagnation point variable sheet thickness homogeneous– heterogeneous reaction
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艾费尔的TDEL技术,平板电视显示的新选择 被引量:2
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作者 吴兴炜 《现代显示》 2006年第11期14-19,共6页
艾费尔科技公司研发出了一种新型的全固体平板显示技术,此项技术由印刷厚膜介电质层和薄膜荧光层组成。艾费尔科技公司的这项专利技术称为无机厚膜电致发光(thickdielectricelectroluminescent,TDEL)技术,在亮度、对比度、色彩、图像质... 艾费尔科技公司研发出了一种新型的全固体平板显示技术,此项技术由印刷厚膜介电质层和薄膜荧光层组成。艾费尔科技公司的这项专利技术称为无机厚膜电致发光(thickdielectricelectroluminescent,TDEL)技术,在亮度、对比度、色彩、图像质量、寿命和制造力等方面不断提高。目前,公司已建成了34in中试线,通过中试生产使技术由研发转向产业化,并将产品投放到高清晰度平板电视市场。 展开更多
关键词 无机膜电致发光 平板电视 电质层
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Effects of gate dielectric thickness and semiconductor thickness on device performance of organic field-effect transistors based on pentacene
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作者 YI Ran LOU ZhiDong +2 位作者 HU YuFeng CUI ShaoBo TENG Feng 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第6期1142-1146,共5页
In this paper,the pentacene-based organic field-effect transistors(OFETs)with poly(methyl methacrylate)(PMMA)as gate dielectrics were fabricated,and the effects of gate dielectric thickness and semiconductor thickness... In this paper,the pentacene-based organic field-effect transistors(OFETs)with poly(methyl methacrylate)(PMMA)as gate dielectrics were fabricated,and the effects of gate dielectric thickness and semiconductor thickness on the device performance were investigated.The optimal PMMA thickness is in the range of 350–400 nm to sustain a considerable current density and stable performance.The device performance depends on the thicknesses of the active layer non-monotonically,which can be explained by the morphology of the pentacene film and the position of the conducting channel in the active layer.The device with a pentacene thickness of 50 nm shows the best performance,which has a maximum hole mobility of 1.12 cm2/V·s.In addition,the introduction of a thin layer of tris-(8-hydroxyquinolinato)aluminum(Alq3)to the OFETs as a light-emitting material greatly decreases the device performance. 展开更多
关键词 pentacene-based organic field-effect transistors(OFETs) thicknesses of poly(methy lmethacrylate)(PMMA) and pentacene device performance
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