Nano Temperature Sensor Using Selective Lateral Growth of Carbon Nanotube Between Electrodes

This paper presents lateral growth of carbon nanotube (CNT) between two electrodes and its use as nano temperature sensor. Fabrication of electrodes is made by MEMS techniques. The CNT is grown selectively by microwave plasma chemical vapor deposition between two electrodes. After wire bonding, the grown CNT is tested and calibrated. The growth conditions of CNT, such as the flow rate of CH₄ or N₂ gas, are varied to obtain a high-quality CNT sensor. SEM is used to observe the shape and structure of CNT, while Raman spectrum analysis is used to indicate the degree of graphitization or amorphous structure in the CNT. The I-V curve of CNT is measured at different temperature, and a linear relationship between the electric resistance of CNT and the temperature is obtained. This result indicates that CNT can be used as a temperature sensor     

The coupling influence of size effects and strain rates on the formability of austenitic stainless steel 304 foil

In order to understand the coupling influence of size effects and strain rates on the formability of the austenitic stainless steel 304 foils in micro scale, a series of micro scale limited dome height (LDH) tests were designed and conducted in three different speeds without lubricant on the annealed and as-received austenitic stainless steel 304 foils. In this study, a technique was developed to coat a layer of pure chromium (≈0.3 μm thick) on the foils and by using the etching process to make the micro square grids (50 μm × 50 μm) on the foils. Then, the foils were annealed at different temperatures for obtaining different microstructures. A set of the forming limit curves (FLC) of the foils were obtained and they can be used by industry right away for product design, process design and development, die design, and simulations, etc. Besides, the coupling influence of the size effects and the strain rates on the formability of the austenitic stainless steel 304 foils has been studied, observed and understood.     

Idiopathic perforation of the colon in a newborn

Although infrequent, idiopathic perforation of the colon in the newborn is a surgical emergency. Etiology remains obscure. Diagnosis of a pneumoperitoneum, prompt operative intervention, and the use of antibiotic therapy are essential to the survival of these infants.     

Optimal short‐term scheduling of shunt compensators via a decomposition algorithm

Abstract

The short term (one day) scheduling of VAr controllers involves the setting of shunt compensators, EHV taps and generator voltages. A decomposition approach is presented to solve the problem of optimal short‐term scheduling of shunt compensators in this paper. The entire problem is decomposed into two levels: the master and the slave levels. The master level deals with minimization of the depreciation cost of compensators in order to reduce the control actions for compensators while satisfying operating constraints. The slave level treats minimization of capitalized MW losses while satisfying system security constraints by adjusting generator voltages and taps. These two levels interact through linear constraints in the iteration process. The IEEE 30‐bus and a practical 265‐bus systems, namely Taiwan Power System, are used to serve as samples to show the applicability of the presented approach.     

Effects of poly(methyl methacrylate)‐based low‐profile additives on the properties of cured unsaturated polyester resins. I. Miscibility,curing behavior,and glass‐transition temperatures

The effects of three series of self‐synthesized poly(methyl methacrylate) (PMMA)‐based low‐profile additives (LPAs), including PMMA, poly(methyl methacrylate‐co‐butyl acrylate), and poly(methyl methacrylate‐co‐butyl acrylate‐co‐maleic anhydride), with different chemical structures and MWs on the miscibility, cured‐sample morphology, curing kinetics, and glass‐transition temperatures for styrene (ST)/unsaturated polyester (UP) resin/LPA ternary systems were investigated by group contribution methods, scanning electron microscopy, differential scanning calorimetry (DSC), and dynamic mechanical analysis, respectively. Before curing at room temperature, the degree of phase separation for the ST/UP/LPA systems was generally explainable by the calculated polarity difference per unit volume between the UP resin and LPA. During curing at 110°C, the compatibility of the ST/UP/LPA systems, as revealed by cured‐sample morphology, was judged from the relative magnitude of the DSC peak reaction rate and the broadness of the peak. On the basis of Takayanagi's mechanical models, the effects of LPA on the final cure conversion and the glass‐transition temperature in the major continuous phase of ST‐crosslinked polyester for the ST/UP/LPA systems was also examined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3369–3387, 2004     

Effects of poly(vinyl acetate) and poly(vinyl chloride‐co‐vinyl acetate) low‐profile additives on properties of cured unsaturated polyester resins. II. glass‐transition temperatures and mechanical properties

Three series of self‐synthesized poly(vinyl acetate)‐based low‐profile additives (LPAs), including poly(vinyl acetate), poly(vinyl chloride‐co‐vinyl acetate), and poly(vinyl chloride‐co‐vinyl acetate‐co‐maleic anhydride), with different chemical structures and molecular weights were studied. Their effects on the glass‐transition temperatures and mechanical properties for thermoset polymer blends made from styrene, unsaturated polyester, and LPAs were investigated by an integrated approach of the static phase characteristics, cured sample morphology, reaction kinetics, and property measurements. Based on Takayanagi mechanical models, the factors that control the glass‐transition temperature in each phase region of the cured samples and the mechanical properties are discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3347–3357, 2003     

Identification of material and geometrical parameters for microstructures by dynamic finite element model updating

This paper describes a procedure to identify material and geometrical parameters for microstructures using the concept of finite element model updating. This scheme utilizes measured and finite element analysis (FEA) natural frequencies that are paired together according to their mode shapes, and it incorporates an optimization sequence that formulates the frequency differences as an error vector to be minimized. To demonstrate the effectiveness of the proposed procedure, two examples are shown in this paper. One example involves a microcantilever fabricated from a single-crystalline silicon wafer, and the updating process is applied on the cantilever to identify its Young’s modulus. The identified Young’s modulus (along <100> direction) of 130.29 GPa is very comparable to those in the literature. The other example concerns a commercial, V-shaped silicon nitride probe used in an atomic force microscope. The natural frequencies and mode shapes of the probe are measured, the FEA performed, and the probe thickness and the Young’s modulus of the silicon nitride substrate determined. The identified thickness is also verified by SEM images of the probe. Both examples show that the updating procedure converged in just a few iterations.     

Micro film cooling performance

A novel idea for micro film cooling experiment is proposed and conducted. Both fabrication of a micro film-cooled device and evaluation of its performance are presented. The film cooling device is placed in a wind tunnel system for evaluation with the blowing parameter (M) ranging from 1 to 12.5 and the film jet slot heights of 25 μm, 45 μm and 50 μm, respectively. The micro film cooling performance obtained is found much higher, and the amount of cooling air used is much less, approximately two or three order magnitude lower, than that in the large-scale film cooling system. This means much saving of power consumption and more engine efficiency.     

镁合金压铸件的生产

叙述了镁合金的特性,并讨论了镁合金贮存、熔炼、精炼以及压铸模具等对生产优质镁压铸件的影响。     

Noncoherent summation of multiple reduced-rank test statistics forfrequency-hopped STAP

A new noncoherent CFAR detection algorithm for STAP radar is developed, which noncoherently integrates a number of coherent, reduced-rank, CFAR tests developed by the authors in a previous paper. This new noncoherent detection criterion provides a significant improvement in detection performance with no need to increase the transmitter power