Resistance Analysis of Spherical Metal Thin Films Combining Van Der Pauw and Electromechanical Nanoindentation Methods

Although micron-sized metal-coated polymer particles are an important conductive filler material in anisotropic conductive adhesives, the resistance of the particles in an adhesive is not well understood. In this study, a van der Pauw method for spherical thin films is developed and applied to determine the resistivity of 30 μm silver-coated poly(methyl methacrylate) (PMMA) particles. The resistivity is used to interpret resistance contributions in single particle electromechanical nanoindentation measurements, which simulate the compression particles undergo in application. The resistivity was found to be coating thickness dependent for thin films in the range 60–270 nm. Estimation of the resistance of the metal shell using the measured resistivity did not account for the total resistance measured in electromechanical nanoindentation. We therefore deduce a significant contribution of contact resistance at the interfaces of the particle. The contact resistance is both coating thickness and particle deformation dependent.     

Effects of Multiple Stacking Faults on the Electronic and Optical Properties of Armchair MoS$$_{}$$ Nanoribbons: First-Principles Calculations

The electronic and optical properties of armchair MoS\(_{2}\) nanoribbons with multiple stacking faults are investigated using first-principles calculations. It’s interesting that the band gaps approach zero for armchair MoS\(_{2}\) nanoribbons with two and four stacking faults. The gaps of armchair MoS\(_{2}\) nanoribbons with one stacking fault and three stacking faults are converged to 0.46 eV and 0.36 eV, respectively, which is smaller than perfect MoS\(_{2}\) nanoribbons. The partial charge density of armchair MoS\(_{2}\) nanoribbons with two stacking faults shows that the defect levels are originated from stacking faults. The frequency-dependent optical response (dielectric function, absorption, reflectance and electron energy loss spectra) is also presented. The optical results of monolayer MoS\(_{2}\) are in agreement with previous study. The peaks in the imaginary part of perfect armchair MoS\(_{2}\) nanoribbons are about 2.8 eV, 4.0 eV and 5.4 eV and the peaks of the imaginary part of armchair MoS\(_{2}\) nanoribbons with stacking faults are mainly 2.8 eV and 5.4 eV. They are independent of ribbon width. The peaks in electron energy loss spectra move toward larger wavelengths (redshift) due to the introduction of stacking faults.     

Familiar/unfamiliar face classification from EEG signals by utilizing pairwise distant channels and distinctive time interval

The aim of the study is to classify single trial electroencephalogram and to estimate active regions/locations on skull in unfamiliar/familiar face recognition task. For this purpose, electroencephalographic signals were acquired from ten subjects in different sessions. Sixty-one familiar and fifty-nine unfamiliar face stimuli were shown to the subjects in the experiments. Since channel responses are different for familiar and unfamiliar classes, the channels discriminating the classes were investigated. To do so, three distances and four similarity measures were employed to assess the most distant channel pairs between familiar and unfamiliar classes for a 1-s time duration; 0.6 s from the stimulus to 1.6 s in a channel selection process. It is experimentally observed that this time interval is maintaining the greatest distance between two categories. The electroencephalographic signals were classified using the determined channels and time interval to measure accuracy. The best classification accuracy was 81.30% and was obtained with the Pearson correlation as channel selection method. The most discriminative channel pairs were selected from prefrontal regions.     

基于数据挖掘方法的多传感器数据融合系统

提出了基于数据挖掘技术的多传感器数据融合方法,根据该方法运用粗糙集--模糊神经网络建立了融合系统模型,给出了系统的原理图,并对系统各部分所用算法进行了研究.最后介绍了该模型的特点,即有较强的通用性,并举例予以说明.     

单晶SiC电化学腐蚀及化学机械抛光

通过电化学工作站对4英寸(1英寸=2.54 cm)n型单晶SiC(4H-SiC)进行电化学腐蚀特性研究,采用36GPAW-TD单面抛光机对其Si面和C面进行了化学机械抛光(CMP)。结果表明,采用H2O2和NaClO作为氧化剂,均可促进SiC的电化学腐蚀并提高其抛光去除速率,其促进作用与氧化剂浓度和抛光液的pH值密切相关。选择含体积分数5%的H2O2、pH值为12的SiO2抛光液对SiC进行CMP,得到的Si面抛光速率可以达到285.7 nm/h。在含H2O2抛光液中引入适量的NaNO3和十二烷基硫酸钠,SiC表现出较高的腐蚀电位绝对值和去除速率。在H2O2和NaClO抛光液体系中,SiC的去除速率与其腐蚀电位的绝对值正相关,该结果对实际应用有一定的借鉴意义。     

CONDITIONAL FACTORIZATION BASED ON LATTICE THEORY FOR 〈K,1〉-INTEGERS

In this paper, the integer N = p^kq is called a 〈k, 1〉-integer, if p and q are odd primes with almost the same size and k is a positive integer. Such integers were previously proposed for various cryptographic applications. The conditional factorization based on lattice theory for n-bit 〈k, 1〉-integers is considered, and there is an algorithm in time polynomial in n to factor these integers if the least significant ｜（2k - 1）n/（3k-1）（k＋1）｜ bits of p are given.     

Performances comparison of pulse-pair and 2-step prediction algorithms for the doppler spectrum estimation

In this work we use real data provided by terminal pulse Doppler radar (WSR-88D) echoes to estimate the windshear hazards disastrous for the aircraft takeoffs and landings. Briefly two different methods are used to estimate the received Doppler moments. The second central moment which is the variance of the wind speed is called width or shear. A first method is in the time domain and also called pulse-pair, while the second is in the frequency domain. The main aim of this study is a performances comparison of results provided by the two mentioned methods and assumes that the power spectrums of the received signals are approached with the Gaussian shape.     

In-situ cleaning and passivation of oxidized Cu surfaces by alkanethiols and its application to wire bonding

The treatment of oxidized Cu surfaces using an alkanethiol as a reducing agent has been investigated. Exposure to a dilute solution of 1-decanethiol resulted in the complete removal and/or conversion of CuO and subsequent formation of a passivating thiolate film, a so-called self-assembled monolayer (SAM), on the underlying Cu/Cu₂O surface as evidenced by x-ray photoelectron spectroscopy (XPS) analysis. Morphological changes, monitored by scanning electron microscopy (SEM) and atomic force microscopy (AFM), revealed transformation of the rough, porous CuO layer into a comparatively smooth Cu/Cu₂O surface. Experiments performed on integrated circuit back-end-of-line (BEOL) die structures, comprising Cu/SiO₂ bond pads used as substrates for Cu wire bonding, demonstrate the potential application of a thiol-based in-situ cleaning-passivation procedure in microelectronics.     

一种WCDMA系统下行信道频偏估计算法及其性能分析

文章在深入研究WCDMA下行链路的信道结构及接收信号处理流程基础上,提出了一种在Rake接收机中,通过对P-CPICH（主公共导频信道）序列两次相关检测实现频偏估计的算法;同时,对该算法主要性能指标进行了分析及仿真,验证了算法的可行性。     

基于Linux的开源智能终端软件栈研究

本文分析了Linux开源社区中主要的移动终端软件栈,从图形显示及GUI应用框架、多媒体框架、进程间通信模块、电话通信模块等方面进行了分析,总结了各种应用架构。