A partially insulated field-effect transistor (PiFET) as a candidate for scaled transistors

Highly manufacturable partially insulated field-effect transistors (PiFETs) were fabricated by using Si-SiGe epitaxial growth and selective SiGe etch process. Owing to these technologies, pseudo-silicon-on-insulator (SOI) structures, partially insulating oxide (PiOX) under source/drain (PUSD) and PiOX under channel (PUC), could be easily realized with excellent structural and process advantages. We are demonstrating their preliminary characteristics and properties. Especially, in the PUSD PiFET, junction capacitance, leakage current, and DIBL in bulk devices could be reduced and the floating body problem in SOI devices was also cleared without any area penalty. Thus, this PiFET structure can be a promising candidate for the future DRAM cell transistor.     

Bit-error probability for maximum-likelihood decoding of linearblock codes and related soft-decision decoding methods

In this correspondence, the bit-error probability P_b for maximum-likelihood decoding of binary linear block codes is investigated. The contribution P_b(j) of each information bit j to P_b is considered and an upper bound on P_b(j) is derived. For randomly generated codes, it is shown that the conventional approximation at high SNR P_b≈(d_H/N).P_s, where P_s represents the block error probability, holds for systematic encoding only. Also systematic encoding provides the minimum P_b when the inverse mapping corresponding to the generator matrix of the code is used to retrieve the information sequence. The bit-error performances corresponding to other generator matrix forms are also evaluated. Although derived for codes with a generator matrix randomly generated, these results are shown to provide good approximations for codes used in practice. Finally, for soft-decision decoding methods which require a generator matrix with a particular structure such as trellis decoding, multistage decoding, or algebraic-based soft-decision decoding, equivalent schemes that reduce the bit-error probability are discussed. Although the gains achieved at practical bit-error rates are only a fraction of a decibel, they remain meaningful as they are of the same orders as the error performance differences between optimum and suboptimum decodings. Most importantly, these gains are free as they are achieved with no or little additional circuitry which is transparent to the conventional implementation     

A study on autobalancing of a casing oscillator using feedback control

The casing oscillator used for basic construction of buildings, factories, and bridges is a construction machine which rotates and rolls the casing to insert it into the ground. It is very important that the casing is retained at a perpendicular position to sea level regardless of the slope of ground. In this paper, we present a new casing oscillator that does need not to be level to the ground for the casing insertion to work. The kinematic analysis for work space of a casing oscillator is presented and carried out with autobalancing of the casing oscillator using feedback control.     

Shock layer in two solute chromatography: effect of axial dispersion and mass transfer

A theoretical study for two solute chromatography when axial dispersion or interphase mass transfer is significant is presented. With a Langmuir isotherm the mathematical theory of the shock layer plays a key role in generating asymptotic solutions, from which one can deduce the effect of axial dispersion or mass transfer resistance. A full discussion is given for the existence and uniqueness of the asymptotic solution. If a shock layer exists, the end states satisfy the compatibility condition and it propagates at the same speed as the corresponding shock. Analytic expressions are developed for the case of equal Peclet numbers (or equal Stanton numbers) whereas for other cases the shock layer profiles are determined numerically. Comparison between transient solutions and shock layers demonstrates the validity and usefulness of the present study.     

Friction properties of a phenolic resin filled with iron and graphite—Sensitivity to load,speed and temperature

A phenolic resin filled with iron and graphite was investigated for its frictional properties sliding against gray cast iron. The frictional force was found to be a power function of the normal load (P) and the sliding speed (V) at a fixed temperature; F = μP^aV^b at T_i where μ is the coefficient of friction which is constant and independent of the load and speed, and a and b are one set of parameters at the temperature T_i. The parameter a is found to range from 0.77 to 0.97 depending upon the temperature. Brake fade is found to be governed by the three mechanisms—load fade, speed fade, and temperature fade.     

Abrasion resistance of silica-reinforced decorative laminates Part 1 — examination of the standard testing method

The existing standard test of the National Electrical Manufacturers Association, U.S.A., (NEMA) for determining the abrasion resistance of decorative laminates was critically examined. Special attention was given to the rapid deterioration of the abrasive paper during testing of silica-reinforced decorative laminates and to its effect on the abrasion resistance of the laminates. It was shown that the abrasion resistance of decorative laminates determined by the present testing method is a combined measure of the properties of the material and the abrasive paper, and that the present testing method is probably not suitable for testing some varieties of decorative laminates, especially those laminates which are reinforced with silica particles.It was also shown that under abrasive wear conditions reinforced overlays may or may not be more abrasion-resistant than unreinforced overlays. It was suggested that the abrasive paper should be replaced before major damage occurred, the degree of damage depending on the properties of the material under test.The frictional force, under abrasive or cutting-type wear conditions, was found to depend strongly on the number of cutting grains and possibly on the size of each scratch. The frictional force thus decreases rapidly with deterioration of the abrasive paper.     

Diffusion of radioactively tagged penetrants through random and block styrene–butadiene copolymers and filled cis-polybutadiene

The diffusion of radioactively tagged n-hexadecane in trace amounts has been studied in 22 random styrene–butadiene (SBR) copolymers with different styrene contents and butadiene microstructures; in several SBR block copolymers with different average block lengths (also diffusion of tagged 1,1-diphenyl ethane); in a triblock SBR copolymer cast from different solvents and also molded at elevated temperature; and in cis-polybutadiene filled to different extents with carbon black, calcium carbonate, and microglass spheres. The diffusion coefficient in random SBR copolymers decreased with increasing content of styrene and/or vinyl configuration and could be correlated with fractional free volume on the basis of linear additivity of the cis, trans, vinyl, and styrene moieties. In SBR block copolymers, the diffusion coefficient increased with increasing average block sequence length. For the triblock copolymer, the diffusion coefficient was approximately the same for samples molded or cast from solvents which are good for polybutadiene, but was far smaller for a sample cast from ethyl acetate, in which the polystyrene domains are probably lamellar. The effect of fillers on diffusion in cis-polybutadiene was compared with calculations on the basis of several theoretical models.     

Diffusion of radioactively tagged penetrants through rubbery polymers. I. Penetrants with very low solubility

The diffusion of radioactively tagged n-hexadecane, 1,7-heptanediol, and ethylene glycol has been studied in one polar and six nonpolar rubbery polymers. The penetrant–polymer pairs included some in which the two components were miscible in all proportions and some in which they were nearly incompatible (solubility of penetrant in polymer of the order of 1%). The theory for the thin smear method for measuring the diffusion coefficient was evaluated for incompatible pairs with two cases: case 2, when the rate-limiting step is diffusion through the polymer; and case 3, when the rate-limiting step is entry into the polymer across the penetrant–polymer interface. They are easily distinguished experimentally from each other and from case 1, which refers to completely miscible pairs. In examples of case 3, e.g., ethylene glycol with butadiene or styrene–butadiene rubbers, the half-time for saturating the polymer surface in contact with the penetrant was found to be several days at 25°C. The diffusion coefficients, when compared in four hydrocarbon rubbers, of n-hexadecane and 1,7-heptanediol were similar in magnitude even though in each rubber the hexadecane was soluble in all proportions and the diol only very slightly. The diffusion coefficient of ethylene glycol, despite its extreme thermodynamic incompatibility, appeared to be somewhat larger than those of the other penetrants.     

Raman spectra of supported molybdena catalysts: II. Sulfided,used, and regenerated catalysts

Raman spectroscopy has been used to investigate the structural changes that two supported molybdenum oxide catalysts undergo upon specific chemical treatments. Molecular MoS₂ structures are indicated after sulfidation by a mixture of $\text{H}{}_2\text{H}{}_2\text{S}$. Catalyst samples used in a coal hydrodesulfurization process yield spectra dominated by intense scattering from carbon deposited in the pores of the catalyst. Spectra of used catalyst samples, subjected to controlled air-firing to 600 °C, show that all of the spectral features of the unused catalyst are not recovered after this “regeneration” procedure.