Ceramic matrix composites derived from CrSi2-filled silicone polycyclic network

Ceramic matrix composites (CMC) were prepared by the active-filler-controlled polymer pyrolysis, using a siloxane polycyclic network filled with CrSi₂. The starting CrSi₂-filled polysiloxane was pyrolyzed in both nitrogen and argon atmospheres, up to 1450°C. During the pyrolysis in nitrogen atmosphere, the CrSi₂ particles reacted with N₂, and also with carbon from the preceramic polymer binder, still complete consumption of the filler particles. Such reactions led to a dramatic change in the composition and microstructure of the resulting ceramic monoliths, which displayed linear expansion of 1.7%. In argon atmosphere, the CrSi₂ particles acted as inert filler during the pyrolysis process. The final CMC compositions obtained in N₂ and Ar atmospheres were Cr_0.62C_0.25N_0.03-Si₃N₄-Cr₃C₂ and SiO_xC_y-SiC-CrSi₂, respectively.     

Reduction of defects and improvement in the performance of blue phosphor for thick‐dielectric electroluminescent displays using Color‐by‐Blue

Abstract— Defect‐free large‐area inorganic thick‐dielectric EL (TDEL) displays using Color by Blue (CBB) technology have been successfully developed. We have achieved the world's highest blue‐phosphor luminance of 900 cd/m² for a single‐pixel device by using CBB and by optimizing the e‐beam gun configuration and the flow rate of H₂S in the vacuum chamber. By analyzing the defects on panels with triple‐pattern phosphors and CBB panels, we also found that the number of defects on CBB panels can be drastically reduced compared with those on triple‐pattern panels. The defect‐free 17‐in. VGA CBB panels show better characteristics, a high peak luminance of 600 cd/m² and a high contrast ratio of 1000:1, compared with those of triple‐pattern panels.     

A two-degree-of-freedom motor-powered gait orthosis for spinal cord injury patients

A number of orthoses have been developed to restore stance and walking in paraplegic subjects. Compliance, however, has been limited, mainly owing to walking effort. Use of the forces produced by actuators is an effective way to solve the problem of the considerable effort required for orthotic gait, namely high muscular effort and high energy expenditure. The purpose of the present study was to investigate the effects of assistance by external actuators on the orthotic gait of spinal cord injury (SCI) patients. Two kinds of linear actuator were developed by using direct current (d.c.) motors for assisting the knee and hip joint of a gait orthosis. They were mounted on the knee and hip joint of a commercial advanced reciprocating gait orthosis (ARGO), and a new two-degree-of-freedom externally powered gait orthosis was thus developed. The orthosis was assessed through inter-subject experiments on five male adult complete SCI patients. Owing to the short training period available for the assisted gait, simultaneous operation of both joint actuators was not conducted: either the knee actuation or the hip actuation was executed only. Thus, the knee actuator and the hip actuator were assessed with a T12 subject and with subjects for T5, T8, T11, and T12 respectively. The motions of the gaits, assisted by the linear actuators, were measured by a Vicon 370 system, and the general gait parameters and compensatory motions were evaluated. Results demonstrated that (a) all subjects could walk without falling, assisted either by the knee or the hip actuator; (b) both the knee and hip joint actuator increased the gait speed and the step length; (c) the knee flexion produced by the orthosis improved the dynamic cosmesis of walking; and (d) lateral compensatory motions as well as vertical ones tended to decrease when the hip joint was assisted, which could contribute to a reduction in walking effort.     

Macroscopic and microscopic changes in the surface layers of annealed and case-hardened steel rollers due to rolling contact

Measurements of the residual stress and observations of the microstructure at the surface and in the subsurface of rollers were performed during rolling contact fatigue tests of annealed 0.45% carbon steel and case-hardened nickel-chromium steel rollers. Compressive residual stresses in annealed rollers were induced by the rolling contact. With case-hardened rollers they were induced by heat treatment prior to the rolling contact fatigue tests. After the rolling contact fatigue tests the compressive residual stresses on the surface of the annealed rollers and in the subsurface of the case-hardened rollers relaxed; a characteristic substructure was formed by the stress cycles, which caused surface failure. It was confirmed that the microcracks leading to surface failure initiate on the surfaces of annealed rollers and in the subsurface of case-hardened rollers.     

Localization of glycosaminoglycans and CD44 in the human lacrimal gland

Recent analyses of tears indicate the presence of glycosaminoglycans as their components, but their origin remains unknown. To further understand the origin of these tear components, we investigated by immunohistochemical techniques the localization of glycosaminoglycans and CD44 human lacrimal glands obtained from 20 cadavers at autopsy. Monoclonal antibodies to CD44, a receptor for hyaluronic acid, dermatan sulfate, chondroitin sulfate, and keratan sulfate were applied to the tissue. Hyaluronic acid binding region was also used for the staining of hyaluronic acid. By light microscopy, immunoreactivity for CD44 was mostly detected on the baso-lateral membrane of acinar and ductal cells, and the vascular endothelium in the interstitium. Positive staining of hyaluronic acid was associated intensely with the basal membrane of acinar and ductal cells and weakly, faintly or not at all with their lateral membrane. Positive staining of hyaluronic acid and immunoreactivity for dermatan sulfate were detected in interstitial fibrous structures; particularly, the former was intense in the perivascular fibrous structures, and the latter along the periparenchimal fibrous structures. Immunoreactivity for chondroitin sulfate and keratan sulfate was seen in some acinar cells and the acinar and ductal lumen. By electron microscopy, immunogold particles indication chondroitin sulfate sulfate or keratan sulfate labeled secretory granules of the acinar cells. Considering the fact that CD44 is a receptor molecule for hyaluronic acid, the association of hyaluronic acid with the basal membrane and weakly or faintly with the lateral membrane of acinar and ductal cells may be attributed to the expression of CD44 on the baso-lateral membrane of the cells. Moreover, the presence of immunoreactivity for chondroitin sulfate and keratan sulfate in secretory granules of acinar cells and their lumens suggests that tears from the lacrimal gland contain these glycosaminoglycans.     

Permeation measurements for investigating atomic hydrogen flux and wall pumping/fuelling dynamics in QUEST

In order to investigate the overall atomic hydrogen background and the dynamic characteristics of wall pumping/fuelling phenomenon, a permeation probe system has been developed and applied in the spherical tokamak QUEST. Reliability of measurements, within ±3% accuracy and a positive correlation with the hydrogen line emission over three orders of magnitude have been demonstrated for more than 3000 various plasma discharges. By comparison of the experimental permeation (flux) curves with the numerically simulated curves, the net incident atomic hydrogen flux is evaluated in the range of 1 × 10¹⁹ H m^?2 s^?1 to 4 × 10²⁰ H m^?2 s^?1. The atomic flux has been investigated as a function of various plasma operation parameters like RF power, gas pressure and magnetic configuration. Using the static particle balance and permeation measurements, the progress in wall conditioning has been investigated. An inverse correlation between the atomic hydrogen flux and improvement in wall pumping has been observed over the two campaigns.     

Double-action bending for eliminating springback in hat-shaped bending of advanced high-strength steel sheet

The International Journal of Advanced Manufacturing Technology - This paper presents a novel technology called ‘double-action bending (DAB)’ to eliminate springback in hat-shape forming...     

Extremely narrow spectral linewidth and low chirping of theMQW-DFB-PPIBH laser diode

The low threshold current of 9 mA, the high side-mode suppression ratio of more than 45 dB, the extremely narrow spectral linewidth of 1.1 MHz, and the low chirping of 2.8 Å at -20 dB at 2 Gb/s nonreturn to zero (NRZ) modulation have been achieved in the multiple quantum well (MQW) distributed feedback (DFB) p-substrate partially inverted buried heterostructure (PPIBH) laser diode. The spectral linewidth of 1.1 MHz is the narrowest value among 300-μm-length solitary laser diodes. These results suggest that the MQW-DFB laser diodes are a promising light source for longer distance and higher bit-rate optical communication systems and coherent optical communication systems     

Generation of pedestal-free 22-fs ultrashort pulse using highly nonlinear fiber and reverse-dispersion fiber

We present an all-fiber system for generating pedestal-free 22-fs ultrashort pulses with a single-peak spectrum. High-power Raman soliton pulses and a normally dispersive highly nonlinear fiber are used to generate a smooth, broadened single-peak spectrum. Then, the higher order dispersion is compensated for using a hybrid fiber composed of a reverse-dispersion fiber and a standard single-mode fiber, which allows pedestal-free ultrashort pulses to be successfully generated. To our knowledge, this is the first demonstration of pedestal-free 20-fs-class ultrashort pulse generation without spectral distortion using an all-fiber configuration.     

Sar1 Affects the Localization of Perilipin 2 to Lipid Droplets

Lipid droplets (LDs) are intracellular organelles that are ubiquitous in many types of cells. The LD core consists of triacylglycerols (TGs) surrounded by a phospholipid monolayer and surface proteins such as perilipin 2 (PLIN2). Although TGs accumulate in the phospholipid bilayer of the endoplasmic reticulum (ER) and subsequently nascent LDs buds from ER, the mechanism by which LD proteins are transported to LD particles is not fully understood. Sar1 is a GTPase known as a regulator of coat protein complex Ⅱ (COPⅡ) vesicle budding, and its role in LD formation was investigated in this study. HuH7 human hepatoma cells were infected with adenoviral particles containing genes coding GFP fused with wild-type Sar1 (Sar1 WT) or a GTPase mutant form (Sar1 H79G). When HuH7 cells were treated with oleic acid, Sar1 WT formed a ring-like structure around the LDs. The transient expression of Sar1 did not significantly alter the levels of TG and PLIN2 in the cells. However, the localization of PLIN2 to the LDs decreased in the cells expressing Sar1 H79G. Furthermore, the effects of Sar1 on PLIN2 localization to the LDs were verified by the suppression of endogenous Sar1 using the short hairpin RNA technique. In conclusion, it was found that Sar1 has some roles in the intracellular distribution of PLIN2 to LDs in liver cells.