A novel multi-phase charge-sharing technique is proposed for the dot-inversion method to reduce AC power consumption of the TFT-LCD column driver without requiring any external capacitor for charge conservation. Simple and easy-to-control circuitry is applied in the proposed method, and the power saving efficiency depends on number of charge phases. Increasing the number of charge phases, the saving power efficiency is also raised. Excluding power dissipation of switches, the power saving efficiency is up to 75% theoretically with infinite phases. For previous work, the maximum power saving efficient is 50% without external capacitor. The HSPICE simulation results including power dissipation of all switches show that the proposed method with seven charge phases (eight-column lines as one group) decreases the power consumption of 23-68% and 10-18%, respectively, compared with original circuit (without any low-power scheme) and previous low-power charge-recycling works.

This paper proposes a compact, low-power, and rail-to-rail class-B output buffer for driving the large column line capacitance of LCDs. The comparator used as a nonlinear element in feedback path is modified from the current-mirror amplifier, which has area and power advantages. The output buffer was realized in a 0.35 m CMOS process. The active area of the buffer is 8673.5 m2. With a 3.3 V supply, the measured quiescent current is 7.4 A. The settling time for 0.05-3.25 V swing to within 0.2% is 8 s.

Most of the current research is focused on the row-column scanning keyboard interface for English letter and number input. At the present time, there are insufficient methods to control the computer mouse effectively. In this study, a categorized row-column scanning computer interface is developed to improve the conventional single key-in row-column scanning method. The beneficial developments include: speed enhancement by categorizing radicals of keyboard, input control of mouse, and multiple selection of input methods such as surface electromyographic (SEMG) control, breath pressure sensibility control with puff, force sensibility control, infrared sensibility control and single key-in control. Meanwhile, an enhancement software package is developed to increase the row-column scanning keyboard capabilities and to upgrade the completeness of the computer mouse for the disabled persons to control the operation of data entry and the associated implementation better.

Electron-cyclotron-resonance plasma-excited molecular beam epitaxial (ECR-MBE) growth of GaN using hydrogen-nitrogen mixed gas plasma was investigated. The growth rate of GaN was drastically increased by addition of hydrogen to nitrogen plasma. The transition of reflection high energy electron diffraction (RHEED) patterns, from streaked patterns created without the presence of hydrogen to spotted patterns in the presence of hydrogen, indicated that the effective V/III ratio was increased by the addition of hydrogen. NHx radical families were detected in hydrogen-nitrogen mixed gas plasma by quadrupole mass spectroscopy and optical emission spectroscopy. These radicals were considered to be responsible for the observed increase in growth rate. Transmission electron microscope observation showed that the surface morphology of GaN without hydrogen was relatively flat and that with hydrogen was columnar with {1 0 ~1 1} facets. It seems likely that the columnar structure of the GaN layers grown with hydrogen were strongly related to initial island growth.

A model of the prefrontal cortical circuit has been constructed to investigate the dynamics for working memory processing. The model circuit is multi-layered and consists of a number of circuit modules or columns, each of which has local, excitatory and inhibitory connections as well as feedback connections. The columns interact with each other via the long-range horizontal connections. Besides these intrinsic connections, the pyramidal and spiny cells in the superficial layers receive the specific cue-related input and all the cortical neurons receive a hypothetical bias input. The model cortical circuit amplifies the response to the transient, cue-related input. The dynamics of the circuit evolves autonomously after the termination of the input. As a result, the circuit reaches in several hundred milliseconds an equilibrium state, in which the neurons exhibit graded-level, sustained activity. The sustained activity varies gradually with the cue direction, thus forming memory fields. In the formation of the memory fields, the feedback connections, the horizontal connections, and the bias input all play important roles. Varying the level of the bias input dramatically changes the dynamics of the model cortical neurons. The computer simulations show that there is an optimum level of the input for the formation of well-defined memory fields during the delay period.

Fast and low-power circuit techniques suitable for size-configurable SRAM macrocells are described. An SRAM cell architecture using virtual-GND lines along bitlines is proposed; each virtual-GND line switches the potential by inner read-enable and column-address-decoded signals. Reducing the active power dissipation in the memory array and shortening the time for writing data are simultaneously accomplished. The range of available supply voltages is enhanced by adoptive higher virtual-GND level control with a simple voltage limiter. An SRAM-macrocell test chip is designed and fabricated with 0.5-µm CMOS technology. A 4K-word6-bit organization SRAM demonstrates 186-MHz operation at a 3.3-V typical power supply. Its power dissipation at a practical operating frequency, 100-MHz, is reduced to 29% (25-mW) by the proposed virtual-GND line techniques.

A regeneration technology of fluorite (CaF2) from spent HF and Buffered HF (BHF) has been investigated. The mechanism of "direct conversion" of granular calcite (CaCO3) into granular fluorite has revealed and several special phenomena are first found to be efficient. An advanced system has been developed. This system regenerates granular fluorite by conversion of granular calcite filled in a column. High purity and low water fluorite is recovered as a substitute for natural fluorspar (CaF2). The fluorine concentration in the processed effluent is minimized to a level of 5 ppm. The separation of the HF processing line and BHF processing line equipped ammonia stripper is an important to system design because ammonia generated from BHF significantly retards the conversion efficiency from CaCO3 to CaF2. The new system reforming the conventional slaked lime processing solves long-pending problem, resulting in a very compact system with a very small amount of product.