Statistical Design of the Four-MOSFET Structure

The statistical design of the four-MOSFET structure is presented in this paper. The quantitative measure of the effect of mismatch between the four transistors on nonlinearity and offset current is provided through contours. Statistical optimization of the transistor and values is demonstrated. The four-MOSFET structure was fabricated through the MOSIS 2 m process using MOS transistor Level-3 model parameters. Experimental results are included in the paper.     

Bulky rigid substitutions: A route to high electron mobility and high solid-state luminescence efficiency of perylene diimide

In this paper, we report that a kind of perylene diimide derivative with bulky rigid substituents, 1,7-bis(p-tert-butylphenoxy)-N,N′-dicyclohexyl-perylene-3,4,9,10-tetracarboxylic diimide (TBPCHPDI) possesses both high electron mobility (1.8 cm² V⁻¹s⁻¹) and high fluorescence quantum yield (0.32) in the solid state. Through X-ray diffraction (XRD), UV–Vis absorption and fluorescence spectra, and differential scanning calorimetry (DSC) measurements, it is demonstrated that the above phenomenon can be ascribed to the unique crystal structure of TBPCHPDI: due to steric hindrance of bulky rigid substituents, the intermolecular π–π actions are neglectable, providing high luminescence efficiency; in the mean time, the spacing between perylene chromophores is still very short (3.47 Å), which is favorable for the hopping transportation of charge carrier from one molecule to neighboring molecule. Therefore, our finding would help design and synthesize novel organic semiconductive materials with potential applications in electrically pumped lasers which require high emission efficiency when large current density is applied.     

泥石流浆体屈服应力的计算方法

大量试验资料表明，泥石流浆体具有屈服应力，很多研究成果表明，浆体屈服应力由两部分组成，即网格结构的联结力和沙粒间的摩擦力，本文以颗粒电化学理论为基础，从理论上导出这两部分的表达式，得到浆体屈服应力公式，并用试验资料进行了验证。     

聚能切割索切割能力仿真及试验研究

为深入研究聚能切割索的切割能力,采用数值仿真和试验的手段研究了聚能切割索（Flexible Linear Shaped Charge,FLSC）切割不同材料铝板的切割效果。仿真和试验结果表明：材料的屈服强度对侵彻性能影响最大,随着被切割对象屈服强度的增大,侵彻深度降低。     

Theoretical design study on the origin of the improved phosphorescent efficiency of DPEphos quinoline-substituted derivatives for OLEDs

Various tetrahedral heteroleptic Cu(I) complexes, as red organic light-emitting diodes (OLEDs), show a concern of maximizing the quantum yield (QY) in order to improve the optoelectronic performance. Herein, three experimental [Cu(N^N) (bis [2-(diphenylphosphino)phenyl]ether)]⁺ (named 1, 2 and 3) were selected as the jumping-off point, following two complexes (named 4 and 5) were successfully designed by introducing bulky electron-donating substituents into N^N ligands continuously. As expected, the QY of designed complexes 4 (0.26) and 5 (0.13) exhibit over twice higher than that of 3 (5.4 × 10⁻²). This can be attributed to the enhanced electron-donating property of N^N ligand, which accelerated the radiative transition rate (k_r) through the apparently elevated energy level of the lowest triplet excited state (T₁) and strengthened transition dipole moments, even though the spin-orbit coupling (SOC) effect is weakened. Simultaneously, the tetrahedral geometric distortion could be effectively restrained by the bulky N^N ligands, but the high vibrational freedom of the terminal substituents could also bring in some unfavorable intra-ligand deformation, resulting in an upward of the nonradiative transition rate (k_nr) at 5 (k_nr: 0.30 × 10⁵ s⁻¹ for 4; 0.95 × 10⁵ s⁻¹ for 5). Therefore, it's worth noting that the balance of excited state energy level, SOC effect as well as the reorganization energy ought to be elaborately regulated to achieve the optimal QY. This detailed investigation on the microscopic mechanism of these Cu(I) complexes can provide instructive inspiration for experimentalists.     

A numerical integration-based yield estimation method for integrated circuits

A novel integration-based yield estimation method is developed for yield optimization of integrated circuits.This method tries to integrate the joint probability density function on the acceptability region directly. To achieve this goal,the simulated performance data of unknown distribution should be converted to follow a multivariate normal distribution by using Box-Cox transformation(BCT).In order to reduce the estimation variances of the model parameters of the density function,orthogonal array-based modified Latin hypercube sampling (OA-MLHS) is presented to generate samples in the disturbance space during simulations.The principle of variance reduction of model parameters estimation through OA-MLHS together with BCT is also discussed.Two yield estimation examples,a fourth-order OTA-C filter and a three-dimensional(3D) quadratic function are used for comparison of our method with Monte Carlo based methods including Latin hypercube sampling and importance sampling under several combinations of sample sizes and yield values.Extensive simulations show that our method is superior to other methods with respect to accuracy and efficiency under all of the given cases.Therefore,our method is more suitable for parametric yield optimization.     

A parametric yield model

Assuming that the distribution of path delays introduced by variations in the manufacturing process is exponential instead of gaussian, the interdependence problem between delay-optimization of synthesized networks and parametric yield has been revisited. The result confirms the claim of Williams, Underwood, and Mercer. The exponential distribution is the consequence of simultaneous occurrence of gate delay faults along the path.     

Analysis and optimisation of the HIPERLAN Channel Access Contention Scheme

This paper analyses the HIPERLAN channel access mechanism. Both a purely mathematical and a simulation model are built in order to evaluate the two successive phases of the contention scheme. Several optimisations, based on the choice of parametric values, are proposed, evaluated and compared.     

一种改进的考虑划痕的关键面积计算模型和方法

关键面积计算对于集成电路成品率的准确预测有着重要的意义。为了得到精确的结果,关键面积计算需要根据缺陷形状的不同选择适当的缺陷模型。针对化学机械研磨引入的划痕,提出了一种线性缺陷模型来计算其关键面积。在此基础上进一步考虑了线端效应的影响,对考虑划痕的关键面积计算模型提出了改进。实验结果表明改进后模型的计算结果更为准确。