Trend transformation of drain-current degradation under drain-avalanche hot-carrier stress for CLC n-TFTs

Continuous-wave green laser-crystallized (CLC) single-grain-like polycrystalline silicon n-channel thin-film transistors (poly-Si n-TFTs) demonstrate the higher electron mobility and turn-on current than excimer laser annealing (ELA) poly-Si n-TFTs. Furthermore, high drain voltage accelerates the flowing electrons in n-type channel, and hence the hot-carriers possibly cause a serious damage near the drain region and deteriorate the source/drain (S/D) current. In this study, at high drain stress voltage, it appears that CLC TFT was degraded in the initial stress time (before 50 s), but the drain current was enhanced after 50 s. After 50 s stress time, the amount of grain boundary trap states near the drain side was getting large and the reflowing holes damaged the source region or injected into gate oxide near source side as well.     

Modeling Harmonic Distortions Caused by Nonlinear Op-Amp DC Gain for Switched-Capacitor Sigma–Delta Modulators

Op-amps are crucial components in sigma-delta modulators (SDMs). As device dimensions and supply voltages continue to scale down, it is increasingly critical to determine a suitable op-amp dc gain. If the dc gain is set too high, then the op-amp consumes too much power; if the dc gain is too small, then nonlinear distortion becomes serious. However, there exists no efficient approach for selecting dc gains. In this brief, we propose to use a nonlinear function to model nonlinear op-amp dc gain curves. Then, this nonlinear function is employed to derive an SDM nonlinear distortion model as a function of SDM system parameters. The obtained SDM nonlinear distortion model can subsequently be used to compute the minimum required op-amp dc gain such that nonlinear distortions are kept under a tolerable value. The nonlinear dc gain curve model and the SDM nonlinear distortion model proposed in this brief are verified by behavior simulations and transistor-level simulations.     

Study of Al–Ti/Si bi-layer as the recording media for write-once HD-DVD optical disks

Optimum structure for HD-DVD optical disks containing Al–Ti/Si bi-layer recording system was identified by reflectivity simulation and dynamic test of disk samples. For the disk sample with optimized structure, the maximum partial response signal-to-noise ratio (PRSNR) of 19.1 dB, minimum simulated bit error rate (sbER) of 1.7 × 10^?7 and modulation >0.6 were achieved at the writing power (P_w) = 11.2 mW. Transmission electron microscopy (TEM) revealed that the polycrystalline granular clusters constitute the recording marks. Subsequent analyses evidenced that element mixing/alloy reactions occur in between Si and Al–Ti layers and the formation of Al_3.21Si_0.47 crystalline phase is responsible for the signal recording in the disk samples.     

Metal–Nonmetal Transition in Rubidium Tungsten Bronze RbxWOy

An oxygen concentration dependent metal–nonmetal (MN) transition was observed for Rb_0.23WO _y with 2.80 < y < 3.08. As 2.80 < y < 3.0, the room temperature resistivity (_RT) of the Rb_0.23WO _y is about 5 × 10^–4 cm. While in the case of y > 3.04, the _RT of the Rb_0.23WO _y exhibits a four orders of magnitude increase with a value of 5 cm. Correspondingly, the lattice constant along c-direction slightly shortens as oxygen concentration increases from 2.80 to 3.08. The observed results suggest that the hybridization between W 5d (t_2g) and O 2p orbitals might be responsible for the MN transition. In addition, similar measurements were performed for Rb _x WO_3.04 and Rb _x WO_2.85 with 0.19 < x < 0.27. No rubidium concentration dependent MN transition was observed, indicating the electronic structure of the host WO _y is not modified significantly by varying the soluble rubidium concentration.     

Ergonomics study on the handle length and lift angle for the culinary spatula

The culinary spatula (turning shovel) is one of the most common cooking tools used in the kitchen in Asia. However, the culinary spatula has seldom been ergonomically investigated. When a person uses a spatula to cook food, the operations involve repetitive bent-wrist motions, such as dorsiflexion, palmary flexion, and radial and ulnar deviations. These movements may cause cumulative trauma disorders in the upper extremities, and in particular carpal tunnel syndrome. A poorly designed culinary spatula will be ergonomically inefficient and cause injury to the hand and wrist. The purpose of this study was to investigate the effects of spatula handle length and lift angle on food-frying, food-turning, and food-shoveling performance. Eight female subjects were tested using 16 different culinary spatulas, with four different handle lengths (20, 25, 30 and 35 cm) and four different lift angles (15 degrees, 25 degrees, 35 degrees and 45 ). The criterion measures included cooking performance, and rating of perceived exertion. The subjects ranked their preference after all of the tasks in the tests were completed. The results showed that: (1) The handle length had a significant influence on the cooking performance, and rating of perceived exertion. The optimal handle lengths for frying food, turning food, and shoveling food were 20, 25 and 25 cm, respectively. (2) The lift angle significantly affected the cooking performance, and rating of perceived exertion. The optimal lift angles for frying food, turning food, and shoveling food were 15 degrees, 15 degrees and 25 degrees, respectively. (3) Both the handle length and lift angle had significant effects on subjective preference. For the handle length, the 20 cm length was the best. For the lift angle, the 25 angle was the best. (4) In general, a spatula with a 20 cm handle length and 25 degrees lift angle was the best. A spatula with a 25 cm handle length and 15 lift angle was the second most preferred. (5) However, to prevent subjects from touching the edge of a hot pan, a spatula with a 25 cm handle length and 25 lift angle is suggested.     

LTPS circuit integration for system‐on‐glass LCDs

Abstract— A 3.5‐in. QVGA‐formatted driving‐circuit fully integrated LCD has been developed using low‐temperature poly‐Si (LTPS) technology. This display module, in which no external ICs are required, integrates all the driving circuits for a six‐bit RGB digital interface with an LTPS device called a “FASt LDD TFT” and achieves a high‐quality image, narrow frame width, and low power consumption. The LTPS process, device, and circuit technologies developed for system‐on‐glass LCD discussed. The development phase of LTPS circuit integration for system‐on‐glass LCDs is also reviewed.     

MEMS-based formaldehyde gas sensor integrated with a micro-hotplate

This paper presents a novel micro-fabricated formaldehyde gas sensor with enhanced sensitivity and detection resolution capabilities. The device comprises a quartz substrate with Pt heaters as a micro-hotplate and deposited formaldehyde-sensing layer on it. A sputtered NiO thin film is used as the formaldehyde-sensing layer. A specific orientation of NiO becomes more apparent as the substrate temperature increases in the sputtering process, which helps the formation of NiO material with a correct stoichiometric ratio. The gas sensor incorporates Pt heating resistors integrated with a micro-hotplate to provide a heating function and utilizes Au inter-digitated electrodes. When formaldehyde is present in the atmosphere, oxydation happens near the sensing layer with a high temperature caused by the micro-hotplate and causes a change in the electrical conductivity of the NiO film. Therefore, the measured resistance between the inter-digitated electrodes changes correspondingly. The application of a voltage to the Pt heaters causes the temperature of the micro-hotplate to increase, which in turn enhances the sensitivity of the sensor. The nanometer scale grain size of the sputtered oxide thin film is conducive to improving the sensitivity of the gas sensor. The experimental results indicate that the developed device has a high stability (0.23%), a low hysteresis value (0.18%), a quick response time (13.0 s), a high degree of sensitivity (0.14 Ω ppm⁻¹), and a detection capability of less than 1.2 ppm.

     

A piezoelectric transducer‐tuned microstrip‐ring resonator oscillator operating at the second resonant mode of the ring resonator

A microstrip open‐loop resonator oscillator operating at even modes is proposed. The even mode of the ring circuit can be predicted by using a simple transmission‐line model. The new oscillator has a characteristic similar to that of a push‐push oscillator. In addition, in comparison with the push‐push oscillator, the new oscillator with one active device can minimize the size and lower the cost. A voltage‐controlled piezoelectric transducer (PET) is used to vary the resonant frequencies of the ring resonator, which in turn tunes the oscillator with a good tuning range of 4.9% at around 12.1 GHz. This tuned oscillator should have many applications in wireless systems. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

A genetic fuzzy agent using ontology model for meeting scheduling system

A Genetic Fuzzy Agent (GFA) using the ontology model for Meeting Scheduling System (MSS) is presented in this paper. The ontology model includes the Fuzzy Meeting Scheduling Ontology (FMSO) and the Fuzzy Personal Ontology (FPO) that can support to construct the knowledge base of the GFA. The FMSO is utilized to record and describe the meeting scheduling domain knowledge for the GFA. In addition, we implement a FMSO editor for generating the Web Ontology Language, OWL, that will be utilized by the GFA. Furthermore, the GFA will infer the suitable meeting time slots based on the ontology model. Moreover, it also adjusts the FMSO and FPO based on the results of the genetic learning mechanism for the next meeting. The experimental results show that our approach can effectively work for MSS.     

Investigation of a solid-state detector for advanced computed tomography

Utilization of solid-state detectors for computed tomography (CT) has been the focus of many studies. Previous phantom and clinical experiments have shown that one of the important performance parameters for the solid-state detector is the primary speed and afterglow. In this paper, we present a detailed investigation on the signal decay characteristics of the HiLight (GE Medical Systems, Milwaukee, WI) scintillating detector. The detector primary speed and afterglow are modeled by a multiexponential function and fully characterized by a set of time constants and relative strengths. The sensitivity of these parameters to X-ray photon energy, detector aging, and radiation exposure is then established and analyzed. No statistically significant variation is observed in these parameters due to changes in the above external variables. The impact of various decay time constants on CT image quality, such as spatial resolution, noise, and artifacts, is subsequently illustrated with computer simulations and phantom experiments. Finally, an algorithmic correction scheme is derived to compensate for detector afterglow. The correction scheme employs a recursive filter to remove adverse effects of the detector decay on image quality. Experimental results have shown that the correction scheme successfully restores system spatial resolution, produces a more homogeneous noise pattern, and eliminates ring-band image artifacts due to detector afterglow. The effectiveness and robustness of the correction scheme are demonstrated by extensive phantom and clinical experiments.