Dissolution of phase-separated domains after a jump to a temperature in the single-phase region

Phase-separated domains prepared in the two-phase region were dissolved at a temperature in the single-phase region, and their dissolution dynamics was studied by using the time-resolved light scattering (TRLS) technique and a scanning electron microscope (SEM). The time t_ps of preparation of domains was chosen to be long enough for phase separation to proceed into the late stage. The scattered light intensity at small wavenumbers increased before it attenuated. As t_ps increased, the increase at smaller wavenumbers became more significant and the peak intensity decreased only slightly with dissolution time. The characteristic wavenumber q_m evaluated from TRLS and SEM followed the power-law relation q_mt^−0.3.     

Mechanical stress control in a VLSI-fabrication process: a method for obtaining the relation between stress levels and stress-induced failures

An ideal fabrication process is designed to minimize mechanical stress in semiconductor devices and to improve device reliability. Mechanical stress levels were predicted by in-house simulations supported by a thin-film database. These stress levels were correlated with stress-induced defects by TEM analysis supported by fail bit addressing on matured megabit SRAMs. Amorphous-doped silicon film with various annealing temperatures were used for the gate electrode to change the mechanical stress in devices and to get the direct relationship between predicted stress levels and stress related defects. The authors describe brief guidelines for suppressing dislocations in the small geometry shallow-trench isolation process utilizing this system. Polysilicon thickness in the W-polycide gate electrode is designed to minimize mechanical stress in the gate oxide and to suppress the gate oxide failure in probe and class tests. Moreover, critical stress generates dislocations during post source/drain ion implantation anneal obtained by a ball indentation method. This indicated that lower temperature anneal is effective in suppressing the dislocations. A two-step anneal was introduced to suppress dislocations and to enable higher ion activation.     

Tradeoffs in granularity and parallelization for a Monte Carlo shower simulation code

The EGS4 code, developed at Stanford Linear Accelerator Center, simulates electron-photon cascading phenomena. The original code is inherently sequential: processing one particle at a time. This paper reports on a series of experiments in parallelizing different versions of EGS4. Our parallel experiments were run on a 30-processor Sequent Balance B21 and a 6-processor Symmetry S27. We have considered the following approaches for parallel execution of this application code:

1. (1) Original sequential version modified for parallel processing: 1 processor;

2. (2) Version 1 run multiprocessed: 1 to 29 processors;

3. (3) Sequential version modified for large-grain parallel processing: 1 procssor;

4. (4) Version 3 run using the Sequent Microtasking Library: 1 to 29 processors.

For each approach, we discuss the relative advantages and disadvantages in the areas of coding effort, understandability and portability, as well as performance, and outline a new parallelization approach we are currently pursuing based on Large-Grain Data Flow techniques.     

STRUCTURE FORMATION OF COATED FILMS WITH DISPERSED PIGMENTS DURING DRYING

In the drying of coated films with dispersed pigments, such as floppy disks, the structure of the film is formed during the drying process and depends on the drying condition. It is important to understand the structure formation during drying for the design of the dryer and die better quality of the product. We measured die drying characteristics of the film and determined the structure of dried film experimentally. A qualitative model for the structure formation during drying of the coated film is suggested.     

Synthesis of polymeric microspheres employing SPG emulsification technique

Relatively uniform polymeric microspheres, the coefficients of variation being close to 10%, were obtained by the BPO-initiated suspension polymerization of styrenic monomers. Unlike the conventional stirred-tank system, a particular microporous glass membrane (SPG) provided uniform monomer droplets continuously when monomer was allowed to permeate through the micropores. The monomer droplets were suspended in an aqueous solution containing the stabilizing agents, transferred to a stirred vessel, and polymerized. Up to 10μm spheres, of a far narrower size distribution than those obtained by conventional microsuspension polymerization spheres, were obtained. The initial droplet size and distribution were retained with the successful suppression of secondary particle nucleation by the addition of hydroquinone in the aueous phase. Crosslinked polystyrene spheres were also synthesized in the presence of various low-molecular-weight diluents. While a good solvent, toluene, was not so effective; poor solvents, n-heptane and n-heptane, easily yielded the microporous structure, the specific surface area being as high as 160 m²/g. © 1994 John Wiley & Sons, Inc.     

Development of cable fault location method using fiber optic distributed temperature sensor

When ground-fault problems occur on a cable line, immediate fault location and restoration are required. Therefore, various new methods to locate the fault point instantaneously have been investigated to replace such conventional methods as the Murray loop method and the pulse radar method [1]. These methods require a long time to locate the fault point. One possible fault location method is to sense the temperature rise following a ground fault using a fiber optic distributed temperature sensor. Application of this method was found feasible through sensing the temperature rise at a ground-fault test using a thermocouple as a temperature sensor with test cables [4]. A power/optical composite cable was prepared experimentally and after verifying its thermal mechanical performance, the temperature rise at an incidence of a fault was determined and the anticipated performance was demonstrated in a ground-fault test. This article describes the outline of the test.     

Multichannel fiber ferrule for a stable laser-diode array module

We developed a multichannel fiber ferrule for a stable laser-diode array module. To apply YAG laser welding to parallel butt couple between the laser-diode and the single-mode fiber arrays, hermetically sealed and precisely aligned equi-interval fibers are required. We describe a V-grooved ceramic ferrule for embedding fibers. Fibers are fixed by soldering, using a flat ceramic lid and aligned with a 250 μm pitch. Our ferrule allowed a metallic, stem mounting laser-diode, to be fixed by YAG laser welding. All 30 samples tested have a leak rate of less than 1×10^-10 atm·cc/s. Optical coupling of fabricated modules was 9.7±0.2 dB and coupling loss change from 25°C to 115°C was within 0.5 dB     

The effect of probability of coalescence on the evolution of bubble sizes in a turbulent pipeline flow: A numerical study

A population balance method in which continuum and discrete phases are integrated is developed to simulate the evolution of polydisperse population of bubbles in a turbulent pipeline flow. The investigation is focused on the effect of the coalescence efficiency on this evolution. A dilute system of bubbles under microgravity conditions is considered. It is found that if the initial coalescence efficiency is low, a slight increase produces a significant effect on the bubble coalescence rate, and thus on the evolution of the population. If, however, the initial coalescence efficiency is high, its increase results in a marginal effect on the way the population evolves. The results of simulations are validated against experimental data on the population mean.     

Metastatic choriocarcinoma of the kidney discovered by refractory hematuria

A 53-year-old male suffered splenic infarction etiologically related to atrial fibrillation and non-obstructive hypertrophic cardiomyopathy. The main clinical manifestations were a one-month history of epigastric and left upper quadrant pain, with tenderness to palpation in the later zone. Laboratory tests revealed a slight leucocytosis (14.700) with left shift and a marked increase in LDH concentration (945 IU). Abdominal CAT and arteriography established the diagnosis, Echography proved normal. Patient evolution was satisfactory with conservative medical treatment. We conclude that splenic infarction should be considered in all cases of acute or chronic pain in the left hypochondrium. The diagnosis is established by CAT, arteriography and hepatosplenic gammagraphy. Medical management is initially advocated, surgery being reserved for those cases involving complications or in which diagnosis is not clear. Emphasis is placed on the main etiological, clinical, diagnostic and management characteristics of splenic infarction.