Use of a High-Work-Function Ni Electrode to Improve the Stress Reliability of Analog SrTiO3 Metal–Insulator–Metal Capacitors

We have studied the stress reliability of low-energy-bandgap high- metal-insulator-metal capacitors under constant voltage stress. By using a high-work-function Ni electrode (5.1 eV), we reduced the degrading effects of stress on the capacitance variation (DeltaC/C), the quadratic voltage coefficient of capacitance (VCC-alpha), and the long-term reliability, in contrast with using a TaN. The improved stress reliability for the Ni electrode capacitors is attributed to a reduction of carrier injection and trapping.     

The variable sampling rate X̄ control charts for monitoring autocorrelated processes

Recent studies demonstrated that the adaptive X? control charts are more efficient than fixed parmeters (FP) X? control chart from statistical and economic criteria. The usual assumption for designing a control chart is that the observations from the process are independent. However, for many processes, such as chemical processes, consecutive measurements are often highly correlated, especially when the interval between samples is small. In the present paper, the observations are modeled as an AR(1) process plus a random error, and the properties of the variable sampling rate (VSR) X? charts are evaluated and studied under this model. Based on the study, the VSR X? chart is faster than the FP, variable sampling interval and variable sample size X? control charts in detecting mean shifts. However, when the level of autocorrelation is high or the process mean shift is large, the advantage of the VSR X? chart is reduced. Copyright © 2008 John Wiley & Sons, Ltd.     

Studies on the inhibitory effect of Graptopetalum paraguayense E. Walther extracts on the angiotensin converting enzyme

This study was aimed at evaluating the kinetic properties and capacities of water (GWE), 50% ethanolic (GE50) and 95% ethanolic (GE95) extracts from Graptopetalum paraguayense for the potential to inhibit angiotensin converting enzyme (ACE). The results showed that GWE, GE50 and GE95 showed potent inhibitory effects on ACE. It was found that the ACE inhibitory activities of all the tested extracts increased with the increase of their concentrations. In addition, the ACE inhibition of the tested extracts of G. paraguayense were significantly reduced after the addition of 1.5 mM ZnCl₂, suggesting the inhibitory action of the extracts may have resulted from the chelation of the ACE zinc cofactor. The inhibition kinetics, analyzed by Lineweaver–Burk plots, revealed that G. paraguayense extracts showed a mixed-type inhibition. A comparison of the 50% inhibition concentration (IC₅₀) and K_i values showed that the ethanolic extracts, including GE50 and GE95 exhibited the more effective ACE inhibitory activity than the water extracts of G. paraguayense.     

Calculation of Two-Dimensional Sections of Liquidus Projections in Multicomponent Systems

A two-dimensional (2D) section of liquidus projection consists of univariant lines of three-phase equilibria between liquid and other phases. It is useful not only for people’s easy visualization but also for retaining important information about the multicomponent liquidus surface, which is critical for understanding and controlling the solidification microstructure. An algorithm is presented for calculating two-dimensional sections of liquidus projections for multicomponent systems. It can project a liquidus surface onto any given two-dimensional section in the compositional space. A hypothetical quaternary system is designed to illustrate the features of the 2D sectional liquidus projections. Then the Nb-Ti-Si-Cr system is used as an example to demonstrate how to apply a 2D sectional liquidus projection to determine the amount of Cr addition into Nb-Ti-Si alloy to affect the liquidus surface of the quaternary system.     

颜料型纳米级墨水色浆的研究

本文从颜料型纳米级墨水色浆（以下简称为纳米色浆）的原材料，工艺和性能参数着手，重点综述了纳米色浆的实验工艺和相关问题的研究情况。纳米色浆作为墨水的基材是生产优良成品墨水的基础，大力推进纳米色浆技术突破研究，对于提高墨水生产和技术水平具有很大的推动作用。     

Automatic design support and image evaluation of two-coloured products using colour association and colour harmony scales and genetic algorithm

Colour plays a key role in determining a consumer’s response to a product’s appearance. Accordingly, this study proposes an automatic design support system which enables a designer either to emulate the colour scheme of a two-coloured product and then to determine its corresponding image perception, or to search for the two-colour combination which most closely meets the required image perception. The proposed system combines a gray theory-based colour-association evaluation method and a colour-harmony-based aesthetic evaluation method to design and evaluate different product-colour schemes. Since colour-harmony theories cannot be implemented directly using the additive primaries (i.e. R (Red), G (Green) and B (Blue)) used in most computer-based colour emulations, this study develops a RGB-based colour-association and colour-harmony measurement scheme to evaluate the image perception of a particular product-colour scheme. In an inverse process, a genetic algorithm is applied to search for the near-optimal colour combination which satisfies the specified product colour-association goal and achieves a high degree of colour harmony. Various case studies involving the design and evaluation of a two-coloured thermos flask are provided for illustration purposes to demonstrate the effectiveness of the proposed method.     

Lattice-Distortion-Enhanced Yield Strength in a Refractory High-Entropy Alloy

Severe distortion is one of the four core effects in single-phase high-entropy alloys (HEAs) and contributes significantly to the yield strength. However, the connection between the atomic-scale lattice distortion and macro-scale mechanical properties through experimental verification has yet to be fully achieved, owing to two critical challenges: 1) the difficulty in the development of homogeneous single-phase solid-solution HEAs and 2) the ambiguity in describing the lattice distortion and related measurements and calculations. A single-phase body-centered-cubic (BCC) refractory HEA, NbTaTiVZr, using thermodynamic modeling coupled with experimental verifications, is developed. Compared to the previously developed single-phase NbTaTiV HEA, the NbTaTiVZr HEA shows a higher yield strength and comparable plasticity. The increase in yield strength is systematically and quantitatively studied in terms of lattice distortion using a theoretical model, first-principles calculations, synchrotron X-ray/neutron diffraction, atom-probe tomography, and scanning transmission electron microscopy techniques. These results demonstrate that severe lattice distortion is a core factor for developing high strengths in refractory HEAs.     

Electrical behaviors for growth of LAST alloys using vapor phase deposition

The well-dispersed crystal structures of LAST (Lead Antimony Silver Tellurium) alloys grown by a vapor phase deposition method are demonstrated to have excellent electrical characteristics in this study. The atomic ratio of Pb to Te in the alloys are kept at 0.85-0.88. The distribution of component concentrations depends on the deposition temperature, and the Ag- and Sb-rich segments are fabricated at high deposition temperature. Experimental data suggest that the higher Sb content in the crystal increases carrier concentration up to ∼10¹⁹ (per cm). The electrical behavior of the crystal is n-type under Sb doping, and it was transferred into p-type once the samples are dominated by Ag doping, which also raises the mobility to a level as high as ∼10³ cm²/V. Test results of this study have indicated that both Ag and Sb elements contribute to the electrical conductivity enhancement, however, an excess amount of Ag may significantly deteriorate the electrical performance instead.