A Statistical Model for Simulating the Effect of LTPS TFT Device Variation for SOP Applications

In this paper, the variation characteristics of low-temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) are investigated with a statistical approach. A special layout is proposed to investigate the device variation with respect to various devices distances. Two non-Gaussian equations are proposed to fit the device parameter distributions, whose the coefficients of determination (R²) are both near 0.9, reflecting the validity of the model. Two benchmark circuits are used to compare the difference between the proposed model and the conventional Gaussian distribution for the device parameter distribution. The output behaviors of the digital and analog circuits show that the variation in the short range would greatly affect the performance of the analog circuits and would instead be averaged in the digital circuits.     

Microwave Absorption Properties of the Carbonyl Iron/EPDM Radar Absorbing Materials

Employing carbonyl iron powder and Ethylene-Propylene-Diene Monomer(EPDM)as the absorbent and matrix,rubber radar absorbing materials(RAM)were prepared.Effects of the carbonyl iron volume fraction and the thickness of the RAM on the microwave absorption properties in the frequency range of 2.6-18GHz were studied,and a mathematical analysis was made using the electromagnetic theory. The experimental results indicate that the minimum reflectivity of the radar absorbing materials continuously decreases with the increase of the carbonyl iron volume fraction,and the absorption peak also moves towards the low frequency for the same thickness of the RAM.The minimum reflectivity of the 3.0 mm RAM is -21.7dB at 3.5 GHz when the volume fraction of carbonyl iron is 45%.The reflectivity of the RAM is not in direct proportional to the thickness of the RAM,when the RAM has the same volume fraction of the carbonyl iron.The reflectivity of the RAM presents a regular trend at a given carbonyl iron volume fraction in the frequency range of 2.6-18 GHz.With the increase of the thickness,the maximum absorption peak moves towards low frequency band,the minimum reflectivity firstly decreases and then increases,and the absorption bandwidth for reflectivity<-10 dB firstly increases and then decreases.The microwave absorption properties of the RAM are determined by the thickness and the composition of the radar absorbing materials. Theoretical analysis indicates that the reflectivity of the RAM is determined by the matching degree of the air’s characteristic impedance and the input impedance.     

Parallel computation of unsteady three-dimensional incompressible viscous flow using an unstructured multigrid method

The development and validation of a parallel unstructured tetrahedral non-nested multigrid (MG) method for simulation of unsteady 3D incompressible viscous flow is presented. The Navier-Stokes solver is based on the artificial compressibility method (ACM) and a higher-order characteristics-based finite-volume scheme on unstructured MG. Unsteady flow is calculated with an implicit dual time stepping scheme. The parallelization of the solver is achieved by a MG domain decomposition approach (MG-DD), using the Single Program Multiple Data (SPMD) programming paradigm. The Message-Passing Interface (MPI) Library is used for communication of data and loop arrays are decomposed using the OpenMP standard. The parallel codes using single grid and MG are used to simulate steady and unsteady incompressible viscous flows for a 3D lid-driven cavity flow for validation and performance evaluation purposes. The speedups and efficiencies obtained by both the parallel single grid and MG solvers are reasonably good for all test cases, using up to 32 processors on the SGI Origin 3400. The parallel results obtained agree well with those of serial solvers and with numerical solutions obtained by other researchers, as well as experimental measurements.     

IEEE 802.11 MAC层协议解析

IEEE 80 2 .11协议的MAC层的有两种控制方式 :中心控制 (PCF)和分布控制 (DCF) ,其中以DCF为主要介质访问控制方式 .DCF以CS MA/CA为主 ,以RTS/CTS消息交换机制为辅 .在PCF下网络中心控制站 (AP)轮询各个工作站实现中心控制方式 .IEEE80 2 .11MAC层采用的主要技术有虚拟载波监听技术 ,帧优先级机制 ,随机退避技术和节能管理技术     

大变形巷道锚杆的力学特性

通过现场和实验室试验对大变形巷道锚杆的力学特性进行了测试 ,揭示了锚杆与围岩相互作用全过程 :初撑→增阻→恒阻→降阻直至失效 ,论述了锚杆阻力下降和失效是大变形巷道锚杆支护所具有的基本规律 .为此 ,对 FLAC3.3中锚杆单元模型进行了修正 ,使其具备模拟锚杆损伤软化的功能 ,并将其成功地应用于工程实践     

基于Lonworks总线技术的变电站综合自动化系统在临汾电网的应用

介绍了分层分布式变电站综合自动化系统的结构、功能和基于Lonworks总线技术的自动化系统的特点 ,并以临汾地区南步亭变电站和九洲堡变电站的综合自动化系统为例 ,介绍了Lonworks总线技术在临汾地区的应用情况     

改良森吉米尔热镀锌工艺在攀钢的应用

介绍了攀钢改良森吉米尔法热镀锌工艺及生产实绩 ,简要分析了轧后带钢表面清洁度对热镀锌产品表面质量和镀层粘附性的影响。由此采取在镀锌前增设清洗段等措施 ,提高了镀锌产品的表面质量和镀层粘附性。     

游乐设施高强度螺栓小角度纵波探伤

近年来，游乐设施无损检测工作不断增加，检测时经常遇到大型游乐设施是用高强度螺栓固定在混凝土基础上，螺栓无法拆卸(一头固定在混凝土基础内)，有时紧固螺母也不便拆卸，表面探伤方法无法实施的情况，故选用超声波探伤方法。     

Carbon fiber reinforced phenolic Resin/Silica ceramer composites—processing,mechanical and thermal properties

Phenolic/silica ceramers were prepared by the sol‐gel method. Carbon fiber reinforced phenolic/silica ceramer composites with high thermal resistance were fabricated. Tetraethyl orthosilicate (TEOS) was used as a monomer for sol‐gel system. Different ratios of the sol‐gel solutoins and phenolic resins were adopted and the resulting ceramers were used as matrices for carbon fiber reinforced composites. The mechanical and thermal properties of the fabricated composites were studied. The results show that the incorporation of inorganic ingredients into the phenolic resins will increase the thermal resistance of the fabricated composites but not affect the flexural strength of the carbon fiber reinforced phenolic/silica ceramer composites up to 60 wt%. The morphologies of the ceramer matrices were examined by SEM. SiO₂ particles from at the gaps between fibers for higher inorganic contents.