Accurate modeling and parameter extraction for MOS transistorsvalid up to 10 GHz

Accurate modeling and efficient parameter extraction of the small signal equivalent circuit of submicrometer MOS transistors for high-frequency operation are presented. The equivalent circuit is based on a quasi-static approximation which was found to be adequate in the gigahertz range if the extrinsic components are properly modeled. It includes the complete intrinsic quasi-static MOS model, the series resistances of gate, source, and drain, and a substrate coupling network. Direct extraction is performed by Y-parameter analysis on the equivalent circuit in the linear and saturation regions of operation. The extracted results are physically meaningful and can be used to “de-embed” the extrinsic effects such as the substrate coupling within the device. Good agreement has been obtained between the simulation results of the equivalent circuit and measured data up to 10 GHz     

Triflavin potentiates the antiplatelet activity of platelet activating factor receptor antagonist on activated neutrophil-induced platelet aggregation

In this study, specific platelet activating factor (PAF) receptor antagonist ginkgolide B (BN52021) was tested for its antiplatelet activity in zymosan activated polymorphonuclear neutrophil-induced platelet aggregation. Triflavin was also tested for its antiplatelet activity compared with PAF receptor antagonist. Triflavin, an Arg-Gly-Asp-containing disintegrin purified from venom peptide inhibited platelet aggregation by interfering with the interaction of fibrinogen with the glycoprotein IIb/IIIa complex. Furthermore, we also report an efficient high resolution method for quantitative analysis of PAF using high-performance capillary electrophoresis (HPCE). The supernatant of polymorphonuclear neutrophils after their activation by opsonized zymosan induces the aggregation of washed rabbit platelets. In rabbit platelets, BN52021 (100-1000 microM) only partially inhibited activated polymorphonuclear neutrophil-induced platelet aggregation, and its maximal inhibition was estimated to be about 79%. Triflavin also partially inhibited platelet aggregation about 82% induced by activated polymorphonuclear neutrophils. Furthermore, after treatment with a combination of triflavin (0.26 microM) with various concentrations of BN52021 (4-1000 microM), the inhibitory effect of platelet aggregation was almost completely. This inhibition was greater than that produced by the individual drugs alone. These results indicate that a combination of glycoprotein IIb/IIIa complex and PAF receptor antagonist could completely inhibit activated polymorphonuclear neutrophil-induced platelet aggregation. In addition, the amount of PAF released from zymosan (6 mg/ml)-activated polymorphonuclear neutrophils was accurately calculated about 11.8+/-1.5 ng/10(6) cells, and did not further increase even at a high concentration of zymosan (10 mg/ml). These results suggest that PAF play a major role in the interaction between platelets and polymorphonuclear neutrophils. This interaction may be important in the pathogenesis of thrombosis and inflammatory diseases. Our present findings support the hypothesis that combination therapy with glycoprotein IIb/IIIa complex antagonists and PAF receptor antagonists may represent a new approach to the treatment of ischemic disorders.     

Opportunity-based age replacement policy with minimal repair

This paper proposes an opportunity-based age replacement policy with minimal repair. The system has two types of failures. Type I failures (minor failures) are removed by minimal repairs, whereas type II failures are removed by replacements. Type I and type II failures are age-dependent. A system is replaced at type II failure (catastrophic failure) or at the opportunity after age T, whichever occurs first. The cost of the minimal repair of the system at age z depends on the random part C(z) and the deterministic part c(z). The opportunity arises according to a Poisson process, independent of failures of the component. The expected cost rate is obtained. The optimal T^* which would minimize the cost rate is discussed. Various special cases are considered. Finally, a numerical example is given.     

Inhibition of morphine-induced tolerance and dependence by a benzodiazepine receptor agonist midazolam in the rat

We investigated whether midazolam administration influenced morphine-induced antinociception and tolerance and dependence in the rat. Antinociception was assessed by the tail-flick (TF) and the hot-plate test (HP 52 degrees C). Morphine tolerance developed after daily single injections of morphine for 11 days. The effect of midazolam on morphine-induced antinociception and tolerance was assessed by giving daily injections of various doses of midazolam for 11 days. The first injection of saline or midazolam was given intraperitoneally and 30 min later morphine (10 mg/kg body weight) was administered subcutaneously. Antinociception was monitored by measuring TF and HP latencies 60 min after the second injection. Midazolam was injected at four different concentrations: 0.03, 0.1, 0.3, and 3 mg/kg body weight. Chronic administration of morphine resulted in the development of tolerance to antinociception in both TF and HP tests, with rats exhibiting baseline antinociception on Day 9. Animals treated with midazolam alone showed little antinociception on Days 3-9. However, midazolam administration in morphine-treated animals attenuated morphine-induced tolerance to antinociception on Days 1-11 as measured by the tail-flick test. Midazolam also decreased the jumping behavior following naloxone injections in morphine-dependent rats. These results suggest that midazolam may prolong the effects of morphine by delaying morphine-induced development of tolerance to antinociception. Midazolam also attenuated a decrease in weight gain induced by chronic injections of morphine.     

The phase transformations and cycling performance of copper-tin alloy anode materials synthesized by sputtering

A sputtering technique was adopted to synthesize Sn-Cu thin film electrodes. Island Sn particles were obtained on the copper foil. Cu₆Sn₅ was spontaneously generated at the interface between Sn and Cu foil. To further improve the cycling stability, Cu source was introduced to increase the formation of Cu₆Sn₅ and to serve as a buffer during cycling. Moreover, the phase and elemental ratio of Sn and Cu varied in the synthesized electrode by alternately adjusting sputtering time for Sn and Cu. The cell synthesized by sputtering Sn for 5 min and Cu for 9 s alternately exhibited the best cycling stability. The 1st charge capacity of cell was 635 mA hg⁻¹, and the 1st efficiency was even higher than 97%. The capacity remained higher than 500 mA hg⁻¹ after 15 cycles. The phase transformation of cell was investigated through voltage profile, CV curve and in situ XRD analysis. The in situ XRD analysis confirmed that Cu₆Sn₅ could react with lithium directly without the presence of Li₂CuSn during cycling. The reaction mechanism of Cu₆Sn₅ with lithium during cycling was demonstrated to be an alloying process, and the structure of Cu₆Sn₅ was thus a low-temperature monoclinic phase.     

Kevlar fiber–epoxy adhesion and its effect on composite mechanical and fracture properties by plasma and chemical treatment

Kevlar 49 fibers were surface-modified by NH₃-, O₂-, and H₂O-plasma etching and chlo-rosulfonation and subsequent reaction with some reagents (glycine, deionized water, eth-ylendeiamine, and 1-butanol) to improve the adhesion to epoxy resin. After these treatments, the changes in fiber topography, chemical compositions of the fiber surfaces, and the surface functional groups introduced to the surface of fibers were identified by SEM, XPS, and static SIMS. Interlaminar shear strength (ILSS) and T-peel strenght between the fiber and opoxy resin, as measured by the short-beam test and T-peel test, were remarkedly improved by gas plasma and chlorosulfonation (0.1% and 0.25% CISO₃H at 30 s). However, from the results of similar G_IC values of the treated and untreated fiber composites, it is clear that the fiber/matrix interfacial bond strength is only a minor contributor to G_IC. SEM was also used to study the surface topography of the fracture surfaces of composites in T-peel test. It could be seen from SEM observations that the improvement of fiber/matrix interfacial bond strength often accompanied a change in fracture mode from the interface of fiber/epoxy resins to the fiber fibrillation and the resins. © 1996 John Wiley & Sons, Inc.     

Analysis of operator-machine configuration for single and multi-processor machines

The research addresses the issue of determining optimal machine-operator configuration so that the ideal machine-operator ratio can be found and the operator efficiency can be calculated as a part of the overall input efficiency. Formula for optimal machine-operator ratio for single and multiple processor machines are derived. The formula allows us how to determine the best machine-operator ratio and calculate the operator usage efficiency. Simulations are used to verify the formula with matching product releasing times and machine utilisation rate. Data from a wafer reclaim factory is used to illustrate the calculation of equipment usage efficiency. Opportunity for doubling operator usage efficiency is identified using the derived formula. Contributions of this work include: (1) deriving a set of formula to calculate optimal operator-machine configuration and the operator usage efficiency for multi-processor machine sets; (2) identifying the inherent unusable time of operator due to the process time distribution of the machine tools; and (3) doubling the operator usage efficiency of the subject factory.     

A proposed process for systematic innovation

A systematic innovation process (SIP) derived from observations of business practices is proposed and exemplified. Time-wise, the SIP is a series of phases and stages which link the planned business processes from business opportunity identification to technology details to cross-industry application exploitation of newly developed technology/tools/products. Resource-wise, the SIP provides a platform to integrate heterogeneous resources and tools such as TRIZ (Theory of Inventive Problem Solving), non-TRIZ tools, and more opportunity identification and problem solving techniques for systematic innovation. Unlike brain-storming type innovation activities which are often ad-hoc and highly dependent on luck, systematic innovation regards the systematic development of innovative problem solving and/or opportunity identification. The proposed SIP is based on the authors’ observations of industry practices and has not been described elsewhere before. The framework integrates the full phases of systematic innovation processes providing a structured process to enable companies to systematically identify business opportunities and key problems, solve problems, and leverage developed tools/products/technologies for cross-industry exploitations. This SIP also allows for the integration of various tools and knowledge within the overall systematic and cyclic process to support systematic innovation.     

Phase Diagrams of High-Entropy Alloy System Al-Co-Cr-Fe-Mo-Ni

The high-entropy alloy system Al-Co-Cr-Fe-Mo-Ni has been previously designed based on the Al _x CoCrCuFeNi system and was demonstrated to have great improvements in toughness at high hardness level and in softening resistance at elevated temperatures. For this promising system, it is important to have phase diagrams for further efficient alloy design and research. The current study combines the results from scanning electron microscopy, transmission electron microscopy, room-temperature and high-temperature x-ray diffractometry, and differential thermal analysis to construct approximate phase diagrams by varying the content of each composing element. Thermodynamic calculation in considering both mixing enthalpy and entropy was also used to justify the simple phase fields in these phase diagrams.