Scalable modeling and comparison for spiral inductors using enhanced 1-π and 2-π topologies

Two different scalable models developed based on enhanced 1-πand 2-πtopologies are presented for onchip spiral inductor modeling.All elements used in the two topologies for accurately predicting the characteristics of spiral inductors at radio frequencies are constructed in geometry-dependent equations for scalable modeling.Then a comparison between the 1-πand 2-πscalable models is made from the following aspects:the complexity of equivalent circuit models and parameter-extraction procedures,scalable rul...     

新型磁驱动增大检测电容的高精度MEMS惯性传感器研究

增大传感器振子的质量和静态测试电容可以减小电容式MEMS惯性传感系统的噪声,而深度粒子反应刻蚀工艺由于复杂的工艺原因,当深宽比较大时,不能刻蚀出大质量和大初始电容的传感器.据此,本文研究了一种磁驱动增大检测电容的MEMS惯性传感器,通过电磁驱动器,传感器的静态测试电容可以大幅增加,在梳齿电容上刻蚀阻尼槽后,其机械噪声达到0.61μg每根号赫兹,仿真其共振频率为598Hz,静态位移灵敏度为0.7μm每重力加速度,基于硅 玻璃键合工艺,制作了栅形条电容式惯性传感器,并用电磁驱动的方式测试其品质因子达到715,从而验证了制作工艺的可行性和电磁驱动器改变传感器初始静态测试电容的可行性.     

基于表面势的HEMT模型分析

将表面势的概念引入GaAs高电子迁移率晶体管器件结构,以建立可精确描述HEMT器件输入/出特性的新模型。通过分析最基本的HEMT结构,参考Si基MOSFET中Pao-sah模型的分析方法,对沟道电荷利用泊松方程表述,并结合能带电压关系,建立HEMT器件中表面势(Φ_s)对于栅压(V_(GS))的关系。基于上述分析计算了沟道中电子的饱和点。根据推导所得方程,模型计算得到的某具体器件沟道面电荷密度(n_s)-栅压(V_(GS))关系曲线和基于T-CAD工具仿真结果在线性区得到很好的吻合。     

沃特世推出最高效的新型ACQUITYUPLCI-Class系统

近日，沃特世（NYSEWAT）公司推出新型Waters ACQUITY UPLC I-Class系统．该系统是目前为止所设计的最高效的UPLC系统，它将分离技术推向了新台阶。     

一种完整且精确的化合物半导体HEMT器件大信号模型

A complete and accurate surface potential based large-signal model for compound semiconductor HEMTs is presented. A surface potential equation resembling the one used in conventional MOSFET models is achieved. The analytic solutions from the traditional surface potential theory that developed in MOSFET models are inherited. For core model derivation, a novel method is used to realize a direct application of the standard surfacepotentialmodelofMOSFETsforHEMTmodeling,withoutbreakingthemathematicstructure.Thehigh-order derivatives of I–V /C–V remain continuous, making the model suitable for RF large-signal applications. Furthermore, the self-heating effects and the transconductance dispersion are also modelled. The model has been verified through comparison with measured DC IV, Gummel symmetry test, CV, minimum noise figure, small-signal Sparameters up to 66 GHz and single-tone input power sweep at 29 GHz for a 475 m0.1 m InGaAs/GaAs power pHEMT, fabricated at a commercial foundry.     

超声振动对渐进成形过程成形力的影响

为研究超声振动对成形过程中塑性变形的作用机理,探究了不同超声振幅与不同步距条件下超声振动对成形力及微观组织的影响。首先,搭建了基于数控铣床的超声辅助渐进成形实验平台,其中施加在工具头上的超声振动振幅可调。然后,进行了不同超声振幅以及不同步距条件下的直槽渐进成形实验,并对轴向和横向成形力进行了采集与分析,对施加超声振动条件后成形件的微观组织进行了观察。结果表明,施加超声振动后轴向力和横向成形力都有所减小,其中横向力的减小效果比轴向力明显,较小步距相比较大步距对于成形力的减小具有更好的效果。成形力下降率随着超声振幅的增大而增大,但是减小幅度会随成形步的增加而减小。     

基于复数权神经元的布尔函数稳健学习算法

复数权神经元由于引入了多阈值逻辑而具有更强的性能.文中根据其数学模型,结合二进感知器神经元稳健设计概念,提出了该神经元的稳健性数学定义,并根据定义,得到了简单逻辑和异或逻辑的单个神经元稳健实现方案.然后根据该方案提出了任意复杂布尔函数稳健实现算法,同时证明了该算法的正确性.最后通过具体实例演示该算法实现布尔函数的过程和...     

弹性螺纹夹头在测量技术中的应用

根据弹性夹头定心夹紧机构的定心原理,设计了以螺纹轴线（螺纹孔或螺纹轴）为基准的零件形位公差检具,以避免了以往此类检具采用螺纹分级使用的烦琐和效率低的问题,提高检测效率,经过测量系统分析及试验验证：这项技术的应用切实可行,检具操作简便、准确可靠。     

一种适合射频功率放大器应用的图形化SOI LDMOSFET新结构

设计并制备了一种新颖的在栅下开硅窗口的图形化SOI LDMOSFET．该器件具有良好的直流和射频特性：输出曲线平滑,没有明显翘曲（kink）效应;静态击穿电压为13V;在栅漏偏压为3．6V时,截至频率为6GHz．负载牵引测试表明,该器件在1．5GHz时,PAE为50％,输出功率为27dBm,表明该器件适合射频功率放大器的应用．     

Investigation and modeling of the avalanche effect in MOSFETs with non-uniform finger spacing

This paper investigates the effect of a non-uniform gate-finger spacing layout structure on the avalanche breakdown performance of RF CMOS technology.Compared with a standard multi-finger device with uniform gate-finger spacing,a device with non-uniform gate-finger spacing represents an improvement of 8.5%for the drain-source breakdown voltage(BV_ds) and of 20%for the thermally-related drain conductance.A novel compact model is proposed to accurately predict the variation of B V_ds with the total area of devices,which is dependent on the different finger spacing sizes.The model is verified and validated by the excellent match between the measured and simulated avalanche breakdown characteristics for a set of uniform and non-uniform gate-finger spacing arranged nMOSFETs.