A computer-aided simulation model for the I–V characteristic of M-n-p silicon Schottky-barrier diodes produced by use of low-energy arsenic-ion implantation

Current-transport properties of Al-n-p silicon Schottky-barrier diodes have been studied both experimentally and theoretically. An analytical model for the I-V characteristic of a metal-n-p Schottky barrier diode has been developed by using an interfacial layer-thermionic-diffusion model. Assuming a Gaussian distribution for the implanted profile, the barrier-height enhancement and ideality factor have been derived analytically. Using low energy (25 KeV) arsenic implantation with the dose ranged form 8 × 10¹⁰/cm² to 10¹²/cm², Al-n-p silicon Schottky barrier diodes have been fabricated and characterized. Comparisons between the experimental measurements and the results of computer simulations have been performed and satisfactory agreements between these comparisons have been obtained. The reverse I–V characteristics of the fabricated Al-n-p silicon Schottky barrier diodes can also be well simulated by the developed model.     

Forecasting the volatility of a combined multi‐country stock index using GWMA algorithms

Globalization has increased the volatility of international financial transactions, particularly those related to international stock markets. An increase in the volatility of one country's stock market spreads throughout the globe, affecting other countries' stock markets. In particular, the Dow Jones Industrial Average plays an extremely important role in the international stock market. This paper uses the generally weighted moving average method and data from the Dow Jones Industrial Average, the National Association of Securities Dealers Automated Quotations, Japan's Nikkei 225, the Korea Composite Stock Price Index, and the Hong Kong Hang Seng Index to predict the performance of the Taiwan Capitalization Weighted Stock Index. This paper attempts to find the smallest prediction error using the optimal combination of generally weighted moving average model parameters and combinations of various international stock market data and compares the results to that found using the exponentially weighted moving average model to explore differences between the two types of forecasting models.     

Sterol synthesis. A timely look at the capabilities of conventional and silver ion high performance liquid chromatography for the separation of C27 sterols related to cholesterol biosynthesis

Sterol intermediates in the biosynthesis of cholesterol have recently assumed a very prominent position in a number of important problems in medicine and biology. In studies of these matters, the separation and identification of the sterol intermediates present formidable challenges, a situation which does not appear to be generally appreciated. High performance liquid chromatography (HPLC) is a simple and rapid approach for the separation of the concerned compounds. Reversed phase HPLC is very commonly used for this purpose. In the present studies, we have evaluated the capabilities of reversed phase, normal phase, and silver ion HPLC for the separation of sterols. Using an extensive collection of authentic sterols, our studies indicate very limited capabilities of reversed phase and normal phase HPLC for the separation of C27 sterols differing in the number and location of olefinic double bonds. In contrast, silver ion HPLC provided remarkable separations of the same compounds, either as the free sterols or their acetate derivatives. These findings, coupled with the results of recent studies of the properties of the same compounds by gas chromatography and by nuclear magnetic resonance and mass spectroscopy, have important implications regarding current application of methodologies for the separation, identification, and quantitation of sterol intermediates in cholesterol biosynthesis as critical portions of investigations on a number of current and emerging problems in biology and medicine.     

A wide‐g range silicon piezoresistive accelerometer

Abstract

In this paper, a high‐performance silicon piezoresistive accelerometer, fabricated by bulk micromachining with an almost linear I/O (acceleration / voltage) relationship from 0 to 90g over a 400Hz bandwidth suitable for vehicle's safety system, is described. This accelerometer is composed of two glass cover caps and a Si sensing structure. The size of the sensing structure is 3.3mm × 2.05 mm × 0.15 mm. It consisted of a “mass”, a “frame”, and 4 thin beam “bridges”. The sensitivity of the accelerometer was found to be 9.6 × 10^‐8 (sec²/m) and a gauge factor of 18 was deduced from this value.     

Application of generally weighted moving average method to tracking signal state space model

In predicting time series, if a trend includes a structural break, then a state space model can be applied to revise the predictive method. Some scholars suggest that restricted damped trend models yield excellent prediction results by automatically revising unforeseen structural break factors in the prediction process. Restricted damped trend models add a smoothed error statistic to a local‐level model and use the exponentially weighted moving average (EWMA) method to make corrections. This paper applies the generally weighted moving average (GWMA) concept and method to a restricted damped trend model that changes the smoothed error statistic from the EWMA form to the GWMA form and adds the correction parameter λ, which distinguishes three situations , , and . The original restricted damped trend model applies only to , enabling the model to capture situations in which and increases its generality. This paper also compares the effect of various parameter values on the predictive model and finds the range of parameter settings that optimize the model.     

Economic design of the integrated multivariate EPC and multivariate SPC charts

The goal of engineering process control (EPC) is to minimize variability by adjusting some manipulative process variables. The goal of statistical process control (SPC) is to reduce variability by monitoring and eliminating assignable causes of variation. As suggested by Box and Kramer and others, it is possible to reduce both special cause and common cause variations by integrating EPC and SPC. In the integrated multivariate EPC (MEPC) and multivariate SPC (MSPC) charts, we propose some statistical and economic criteria, such as the average Euclidean distance from the target vector and the average quality cost (AQC) to evaluate the performance of the MEPC/MSPC charts. The traditional average run length (ARL), average Euclidean distance and AQC of three MSPC charts are investigated and compared. The results of the simulations show that the MEPC/MGWMA chart is more effective and more economical than both the MEPC/MEWMA chart and the MEPC/Hotelling multivariate chart in detecting small shifts of the mean vector. Copyright © 2006 John Wiley & Sons, Ltd.     

Nuclear factor-kappaB as a switch in regulation of resveratrol-mediated apoptosis and erythrocytic differentiation in human leukaemia cells

Resveratrol exerts functions relating apoptosis and differentiation; nonetheless, the mechanisms remain unclear. We examined the regulation of resveratrol on apoptosis and erythrocytic (E)-differentiation in leukaemia cells. The results showed that resveratrol treatment for 24 h induced apoptosis in human leukaemia NB4, HL-60, and U937 cells. Resveratrol-treated K562 cells underwent erythrocyte (E)-differentiation and cell cycle arrest in S-phase, without apoptotic induction in the early stage, but with marked apoptosis in the later stages. Resveratrol-induced apoptosis could be accompanied by P38 downregulation, and E-differentiation could occur with PI3K/Akt upregulation. Downstream NF-κB was increased by resveratrol treatment for 24 h, while luciferase activity was decreased by resveratrol treatment for 72 h. Similar changes were discovered for nuclear levels and NF-κB-DNA binding activity. In conclusion, resveratrol induced differential responses through different signalling pathways, including PI3K/Akt and P38/MAPK, leading to opposing expressions of NF-κB. NF-κB could be a switch for regulating E-differentiation and apoptosis in resveratrol-stimulated K562 cells.     

In situ lamination of starch‐based baked foam packaging with degradable films

A technique for making biodegradable food service packaging comprising a starch–fibre core and a biodegradable film laminate is described. The biodegradable films were made of polylactic acid (PLA), polybutylene succinate/terephthalate (PBST), rubber latex and polybutylene adipate/terephthalate (PBAT). The technique involved an in situ process for laminating a baked foam product in a single step. A critical element of the in situ technique involved using a heat insulating fibre sheet to stabilize heat‐sensitive laminate films during the baking/lamination process. The PLA‐, PBST‐ and PBAT‐laminated samples were baked for 6min at 120°C. The latex‐laminated sample, which was much more heat‐stable, did not need the insulating sheet and was baked for 3min at 160°C. Starch‐based foam laminated with PLA, PBST or PBAT generally had higher density and greater tensile and flexural strength than the non‐laminated control. Starch foam laminated with a rubber latex film had tensile and flexural properties similar to the non‐laminated control, due to the low modulus and elasticity of the latex film. The in situ lamination process improved the adhesion of the starch foam core with the fibre sheet, PLA and latex films compared to a post‐lamination process. All of the laminate materials provided a low water vapour permeance. The films degraded in a compost mixture but at a much slower rate compared to starch. Copyright © 2006 John Wiley & Sons, Ltd.     

Robust Estimation for Weibull Distribution in Partially Accelerated Life Tests with Early Failures

Maximum likelihood estimation (MLE) is a frequently used method for estimating distribution parameters in constant stress partially accelerated life tests (CS‐PALTs). However, using the MLE to estimate the parameters for a Weibull distribution may be problematic in CS‐PALTs. First, the equation for the shape parameter estimator derived from the log‐likelihood function is difficult to solve for the occurrence of nonlinear equations. Second, the sample size is typically not large in life tests. The MLE, a typical large‐sample inference method, may be unsuitable. Test items unsuitable for stress conditions may become early failures, which have extremely short lifetimes. The early failures may cause parameter estimate bias. For addressing early failures in the Weibull distribution in CS‐PALTs, we propose an M‐estimation method based on a Weibull Probability Plot (WPP) framework, which leads a closed‐form expression for the shape parameter estimator. We conducted a simulation study to compare the M‐estimation method with the MLE method. The results show that, with early‐failure samples, the M‐estimation method performs better than the MLE does. Copyright © 2015 John Wiley & Sons, Ltd.