Particle-size analysis by laser diffraction with a complementary metal-oxide semiconductor pixel array

Existing laser-diffraction instruments that use photodiode detectors have a limited resolution for particle sizing. We attempt the implementation of a complementary metal-oxide semiconductor pixel sensor for particle-size measurement by laser diffraction. The sensor has unique features: high resolution, no blooming, and a wide dynamic range (i.e., direct measurement of the scattering pattern). The calibration of the sensor is based on each pixel. The signal-processing and the inversion schemes for obtaining the particle-size distribution are described. The results indicate an improved size resolution and an increased flexibility of application.     

0.18-microm complementary metal-oxide semiconductor push-pull vertical-cavity surface-emitting laser driver operating at 2.5 Gb/s with symmetric rising and falling edges

A vertical-cavity surface-emitting laser (VCSEL) driver design that utilizes a novel push-pull circuit topology is described. The VCSEL driver design can provide both a current pushing and a current pulling mechanism and therefore is capable of producing symmetric rise and fall times. The design was implemented in a 0.18-microm foundry n-well complementary metal-oxide semiconductor technology and operates at data rates up to 2.5 Gb/s with a power consumption of 45 mW at an average optical output power of 1 mW.     

Demonstration of synaptic and resistive switching characteristics in W/TiO2/HfO2/TaN memristor crossbar array for bioinspired neuromorphic computing

In this study,resistive random-access memory (RRAM)-based crossbar arrays with a memristor W/TiO2/HfO2/TaN structure were fabricated through atomic layer deposi...     

SiGe channels for VT control of high-k metal gate transistors for 32 nm complementary metal oxide semiconductor technology and beyond

GLOBALFOUNDRIES 32 nm high-k metal gate technology, with SiGe channel for V_T control of P-field effect transistor, is taken into production. This epitaxial channel material is being introduced into high volume manufacturing in complementary metal oxide semiconductor technology. The morphology of the SiGe channel (cSiGe) for narrow width transistors is carefully controlled by process conditions such as epitaxial growth temperature, pre bake condition or in-situ Si recess prior epitaxial deposition. A micro loading effect observed in 28 nm technology was eliminated by an in-situ recess of the silicon before epitaxial deposition. Due to the significant cost of this process step, an epitaxial batch system has been evaluated to reduce the cost of ownership dramatically. Also the cSiGe process has been optimized to minimize the thickness variation of the SiGe channel due to the strong response of V_T to cSiGe thickness.     

Optimised design of multi-band cellular base station antenna array for GSM and UMTS deployment

A tri-band dual polarised printed patch array is designed for GSM and UMTS cellular deployment using an efficient moment method code driven by a marginal distribution optimisation algorithm. Novel techniques are introduced to expedite analysis while maintaining adequate accuracy, and two methods are used to aggregate elements into an array for pattern synthesis: unequal spacing and phasing. Optimisation criteria such as crosspolar isolation, return loss and radiation pattern characteristics are successfully achieved in simulation, and a measured prototype element supports the antenna concept.     

红外焦平面失效元处理方法及软硬件实现

失效元对红外焦平面阵列器件成像质量的影响较大。本文在给出失效元定义的基础上,对失效元的产生机理进行了分析,并给出了具体的失效元检测方法。基于DSP实现了红外图像的硬件处理系统并编写了失效元处理的软件程序,实现了失效元的自动检测和校正。实验结果表明,所设计的软硬件符合实时性、可靠性的要求,取得了较好的处理效果。     

Inverse heat transfer analysis for design and control of a micro-heater array

A non-linear inverse heat source identification problem is described and solved. The inverse problem analysis is used in the design of an embedded micro-heater array and to estimate the required control settings, which are the input currents to each heating element, to generate as close as possible to a prescribed temperature profile on the surface of a thin copper film. The purpose of the micro-heater array is to control the local copper microstructure through control of the local temperature field. A finite element model of the micro-heater system is used to define a discrete set of non-linear equations used as a basis for the inverse problem solution. Two methods are explored to solve the inverse problem, a direct minimization method with Tikhonov regularization and a passivity-based feedback control algorithm. A uniform and a linear temperature distribution could be attained in the central region above the micro-heater array, but the temperatures near the edges of the domain could not be controlled due to heat loss at the edges. Thus, to control the temperature field over the full width of the domain, the heater array must extend beyond the domain of interest. Both methods to solve the inverse problem are found to perform well. The regularization method allows for a smoother solution, while the feedback control method is simpler as the coefficient matrix for which the update remains unchanged for each iteration.     

Dislocation array elements for the analysis of crack and yielded zone growth

Stress fields were found for boundary elements that consist of linear arrays of dislocations, or arrays of dislocations that simulate a crack tip. A number of two-dimensional elastic boundary value problems were solved using these elements. Crack growth paths were predicted for pairs of interacting cracks and the energetics of multiple crack growth away from a free surface was analysed. In certain simple elastic-plastic problems, where the general shape of the plastic zone is known, the plastic zone size was predicted.     

Application of integrated sensing and processing decision trees for target detection and localization on digital mirror array imagery

We demonstrate the applicability of integrated sensing and processing decision trees (ISPDTs) methodology to a set of digital mirror array (DMA) hyperspectral imagery. In particular, we demonstrate that ISPDTs can be used to detect and localize targets by using just a few DMA Hadamard frames, so that an entire hyperspectral data cube need not be collected to successfully perform the given task. This suggests that such an integrated sensing-processing suite may be appropriate for extremely time-sensitive pattern-recognition applications.     

飞机抖振响应数据处理及分析方法

为了编制抖振疲劳谱、估算抖振疲劳寿命等,必须预先对时域的抖振响应数据进行处理与分析。考虑到抖振响应的随机特性,特别是其显著的分散性,建立了统计模型来对其分析处理。针对同一飞行状态下数据仓中的抖振响应数据,将其划分为若干子数据块,以子数据块中数据统计特征来描述对应子数据块均方根下的响应分布情况,而以对应飞行状态下各子数据块的均方根分布情况来描述该状态下抖振响应的总体分布趋势以及选择其关键响应状态水平。首先,采用威布尔分布假设,运用极大似然估计法对子数据块的数据进行分布参数估计,并给出了分布假设的检验方法;然后,采用“三步进”经验函数来描述抖振响应均方根的分布规律。在本文研究的基础上,根据给出的抖振数据处理与分析结果使用流程,即只需根据确定的几个关键均方根水平,定位到相应的子数据块,再结合子数据块数据的统计模型得到对应飞行状态下的响应分布,就可用于飞机设计与强度校核。由实际飞行试验抖振数据的处理与分析表明,此方法具备一定的合理性     

Preparation,processing and analysis of physical properties of calcium ferrite-CNTs/PET nano-composite

The present work is focused on the preparation of composites based on Poly(ethylene terephthalate) (PET) and novel nano-hybrid filler composed of Calcium Ferrite (CF)-Carbon Nanotubes (CNTs), obtained by direct growth of CNTs on CF based iron catalysts. The carbon content in the hybrid filler was 76 wt%. Composites loaded with 1.0, 1.5, 2.0, 3.0 wt% of filler were obtained by melt compounding and processed by thin-wall injection molding. Unfilled Poly(ethylene terephthalate) was processed using the same techniques. Structural characterization and physical properties (thermal, mechanical and electrical) were analyzed and correlated to the hybrid filler loading, and to the percentage of carbon nanotubes.     

Integration of a photodiode array and centroid processing on a single CMOS chip for a real-time shack-Hartmann wavefront sensor

A real-time VLSI optical centroid processor has been developed as part of a larger Shack-Hartmann wavefront sensor system for applications in adaptive optics. The implementation of the optical centroid detection system was demonstrated successfully using a hardware emulation system. Subsequently, the design has been implemented as a CMOS single-chip solution. This has advantages in terms of speed, power consumption, system size, and cost. The design of the different components of the system will be discussed along with test results of the fabricated device.     

Performance analysis of assembly/disassembly systems with unreliable machines and random processing times

This paper presents an efficient method to evaluate performance of tree-structured assembly/disassembly (AD) systems with finite buffer capacity. The times to failure, the times to repair, and the processing times are assumed to be exponentially distributed. The method is based on an extension of a decomposition method originally applied to performance evaluation of transfer lines. The method decomposes a K-machine tree-structured AD system to a system of K-1 two-machine lines and then finds the processing rates, failure rates and repair rates of the decomposed system that make performance of the two systems close to each other. To determine those rates of the decomposed system, we derive 6(K-1) equations based on interruption of flow, resumption of flow, and flow rate-idle time relations, and suggest two methods, which use the equations in different ways. Results from computational experiments show that the suggested decomposition methods give good estimates in a short time.     

Performance analysis of assembly/disassembly systems with unreliable machines and random processing times

This paper presents an efficient method to evaluate performance of tree-structured assembly/disassembly (AD) systems with finite buffer capacity. The times to failure, the times to repair, and the processing times are assumed to be exponentially distributed. The method is based on an extension of a decomposition method originally applied to performance evaluation of transfer lines. The method decomposes a K-machine tree-structured AD system to a system of K - 1 two-machine lines and then finds the processing rates, failure rates and repair rates of the decomposed system that make performance of the two systems close to each other. To determine those rates of the decomposed system, we derive 6(K - 1) equations based on interruption of flow, resumption of flow, and flow rate-idle time relations, and suggest two methods, which use the equations in different ways. Results from computational experiments show that the suggested decomposition methods give good estimates in a short time.     

圆柱阵主动声纳空时混响仿真及空时特性分析

经典的单元散射模型混响仿真方法无法应用于主动声纳空时自适应处理（space-time adaptive processing,STAP）算法研究。提出了一种基于单元散射模型的适合主动声纳STAP算法研究的圆柱阵混响仿真方法。根据声纳发射信号的距离和多普勒分辨力将海洋空间划分成若干个散射单元,将每个散射单元对各个通道混响的贡献在时域分别进行求和,得到各个通道的混响时间序列。仿真综合考虑了多种影响混响的因素,包括发射信号的参数、声呐平台的运动、海洋环境等。对仿真结果的空时特性进行了分析,结果表明仿真数据能够满足STAP算法研究的需要。     

Comparative analysis of triple band S-C-L erbium-doped fibre and semiconductor optical amplifier for CWDM applications

The authors present a comparative analysis between a triple-band S-C-L erbium-doped fibre amplifier and a commercial semiconductor optical amplifier in a CWDM application scenario. Both technologies were characterised for gain and noise figures from 1480 to 1610 nm (S, C and L bands) and their systemic performances were evaluated in terms of bit error rate measurements for a wide range of optical power levels.     

Factorial design,processing, characterization and microstructure analysis of PIP-based C/SiC composites

Polymer impregnation and pyrolysis (PIP) process-based C/SiC composites are fabricated using the in-house synthesized methyl-polycarbosilane (PCS). Two-level factorial design matrix is employed to carry out experiments to study the effect of four factors on flexural strength of the composite. Total sixteen sets of composite samples are fabricated. Response table, normal probability plot, ANOVA and regression analysis are carried out to determine the statistical significant factors. Composite density (\(\rho \)), fibre volume fraction (\(V_{\mathrm{f}}\)) and pyrolysis temperature (T) are found to be statistically significant, while softening point (SP) of the PCS and interaction of these four factors are found insignificant. Higher levels of the density and \(V_{\mathrm{f} }\) have shown positive effect, while the pyrolysis temperature has negative effect on the flexural strength of the composites. Flexural strength was found to be in the range of 374–592 MPa depending on the process parameters. The mechanical behaviour of the composites at different process conditions was explained with the help of their microstructures.     

Performance analysis of decision-feedback equalisation for cellular mobile radio with cochannel interference and fading

The error probability of minimum-mean-square-error decision-feedback equalisation (MMSE-DFE) is evaluated for digital cellular mobile radio systems in the presence of cochannel interference (CCI) and is compared with linear equalisation (LE). The main contribution of the paper is that this analysis accounts for pulse waveform, modulation and fading of the signal of interest, as well as the CCI. Quadrature-amplitude modulation (QAM) signalling in frequency-selective and quasi-static channels is considered. The CCI is treated as a stationary process, when caused by random phase and symbol-timing offsets relative to the signal of interest. Analysis includes techniques combining antenna diversity. The performance improvement as a function of taps in both feedforward and feedback filters is quantified. Owing to residual intersymbol interference (ISI) and CCI, the evaluation of the error probability is extremely complicated and time consuming in simulation. To overcome this issue, an efficient method based upon Gauss quadrature rules (GQR) is presented to compute the error probability. The method is not limited due to interference statistics and it yields remarkable advantages compared with other methods. The convergence of finite-length results to their infinite-length counterparts is also provided. Unlike the case of white noise, the simulations reveal that with the same finite length the DFE is unable to outperform the linear equaliser in a CCI-dominated channel if the feedback filter is of insufficient length.     

Development of a human information processing model for cognitive task analysis and design

High costs and long cycle times of software development are factors hindering the analysis and design of the complete cognitive aspects related to task performances. Reusable software has been proposed as a solution to the problem of high software development and maintenance costs. One of the paradigms for reusable software, object-oriented modelling, has emerged as an important method for specifying, creating and reusing software modules. Using Unified Modelling Language, this paper develops an object-oriented cognitive task analysis and design (OOCTAD) model based on human information-processing theory. First, human task performance-related cognitive aspects are classified into modules and logically linked together; secondly, cognitive aspects within these modules were further decomposed into packages and classes based on object-oriented technology. Finally, one case study was presented to compare and contrast different cognitive analysis models to illustrate the advantages of the OOCTAD model developed in the current research over the other five cognitive task analysis models. These reusable classes in the OOCATD model were shown to be reused to reduce software development costs and cycle times for cognitive task analysis and design. The current research should be of use to both developers and users of cognitively based tasks, systems and tools and researchers and practitioners in the broader discipline of cognitive tasks design and analysis.