Flow properties of molten ethylene–vinyl acetate copolymer and melt fracture

In an investigation of the behavior and formation mechanism of melt fracture the flow properties of molten ethylene–vinyl acetate (EVA) copolymer in the region of high shear rate were measured with a capillary-type rheometer. EVA copolymer differs slightly in flow curve from low-density polyethylene (LDPE); it seems, however, that the difference is due to the difference in molecular weight distribution (MWD) rather than to the materials themselves. The fluidity of molten EVA copolymer having a narrow MWD is equivalent to that of LDPE having a broad MWD and, generally, EVA copolymer has a higher fluidity than LDPE. It is expected that the fluidity increases with incorporation of vinyl acetate at the same MWD and the same M?_w. The critical shear rate increases with melt index and temperature. It cannot be found that the materials themselves and the MWD directly influence the critical point of melt fracture formation when the melt index is taken as a parameter. The critical viscosity (η_c) at which melt fracture forms decreases in an almost straight line with an increase of melt index. It was found from the studies of end correction and behavior of melt fracture formation that melt fracture occurs at the inlet of the die, and it is supposed that the melt fracture formation is caused by the elastic turbulence in the flow pattern due to a failure of recoverable shear strain at the die inlet.     

Smart integration and packaging of 2D VCSEL's for high-speedparallel links

This paper reviews recent progress in the integration and packaging of two-dimensional (2D) vertical-cavity surface-emitting laser (VCSEL) arrays being developed for the use in high-speed parallel optical interconnections. It reviews the smart integration of VCSEL's with detecting, switching and latching functions through the integration of a VCSEL-thyristor and double-cavity phototransistor. It also describes self-alignment-packaging technologies for 2D VCSEL module that can be used in high-density parallel links. Various system applications, such as a distributed fiber switch used to enable crossbar interconnections with address switching functions and hyper-parallel transmission using an image fiber, are also examined     

Simple nonlinear magnetic analysis for permanent-magnet motors

This paper presents a simple nonlinear magnetic analysis for a surface-mounted permanent-magnet synchronous motor as an assistant design tool of finite-element analysis (FEA). The equivalent magnetic circuit of the motor used in the proposed analysis is composed of the saturable permeance tips in the stator teeth for considering the local magnetic saturation. As a result, the proposed analysis is capable of calculating the flux distribution and the torque characteristics in the presence of magnetic saturation. The effectiveness of the proposed analysis is verified by comparing with three-dimensional (3-D) FEA in terms of the analytical accuracy. The computation time is greatly reduced as short as 1.5 s while the 3-D FEA requires as much as 32 min for the same evaluation.     

Generator and exciter parameter estimation of Fort Patrick HenryHydro Unit 1

This paper describes the techniques employed for extraction of device parameters for a 20 MVA hydro-turbine generator in the Tennessee Valley Authority (TVA) power system. Several approaches were implemented in the extraction of parameters. Measurements on the generator were made prior, and subsequent, to extensive rework as part of a generator upgrade project. In addition, static exciter and overall response tests on the complete system were performed after the upgrade. The identified generator parameters before and after the upgrade are compared     

High glycosylated hemoglobin levels increase the risk of progression to diabetes mellitus in subjects with glucose intolerance

The relationships between HbA1c level and oral glucose tolerance test (OGTT) at the initial visit and the incidence of diabetes after 5 years of follow-up were investigated in 819 subjects participating in a general health examination. The 100 g OGTT was performed. In order to use WHO criteria, the blood glucose levels of 100 g OGTT corresponding to those of 75 g OGTT were adopted according to the recommendations of the Japan Diabetes Society. Subjects other than diabetic type and IGT (impaired glucose tolerance) were divided into a normal group (fasting blood glucose < 100 mg/dl, 1-h blood glucose < 160 mg/dl, a 2-h blood glucose < 120 mg/dl) and a borderline group (the remaining subjects). In IGT, the incidence of diabetes in the low- (< or = 6.3%), intermediate- (6.4-6.7%) and high-HbA1c (> of = 6.8%) groups were 10.4%, 23.1% and 52.5%, respectively (high vs intermediate and low, P < 0.001; intermediate vs low, P < 0.05). In the borderline group, the incidence were 2.8%, 14.3% and 28.6%, respectively (high and intermediate vs low, P < 0.001). The results showed that the combination of HbA1c level and OGTT enables more precise prediction of progression to NIDDM in subjects with glucose intolerance.     

Development of QTAT online electronic circuit patterning system

An arbitrary pattern exposure system has been developed by employing a liquid crystal display (LCD) with 1600 /spl times/ 1200 pixels for the formation of projection images in place of a conventional reticle. The minimum pattern size becomes 11.5 /spl mu/m, which corresponds to the aperture size of each pixel on the LCD. For the purpose of quick turnaround time (TAT), the exposure system was directly connected to the circuit design system with the transmission control protocol/internet protocol network. From the experimental results on patterning of a typical electronic circuit data with the area of 46/spl times/ 46 mm, it was confirmed that the TAT from the output of design data to the finish of the exposure becomes less than 28 min. By using this system, reduction of the production cost in the printed wiring boards fabrication is expected.     

Concentration of lidocaine affects intensity of sensory block during lumbar epidural anesthesia

OBJECTIVE: The use of chemotherapeutic drugs in pregnancy is a rare occurrence. Experience and results need to be shared. METHOD: At 23 weeks gestational age, a patient was diagnosed with an endodermal sinus tumor of the ovary. She received one course of postoperative bleomycin, cisplatin, and etoposide. One week later, the patient was investigated for increasing abdominal pain and the fetus was noted to have ventriculomegaly. RESULTS: The baby was delivered, and the patient was surgically staged and completed chemotherapy. Although the patient is alive and well 16 months after delivery, the infant has developed significant ventriculomegaly with cerebral atrophy. CONCLUSION: The etiology of this infant's significant cerebral atrophy is not clear. Tumor-specific, perioperative, or drug-related events must be considered.     

Role of endogenous endothelin in the development of graft arteriosclerosis in rat cardiac allografts: antiproliferative effects of bosentan, a nonselective endothelin receptor antagonist

BACKGROUND: The purpose of this study was to determine whether endothelin-1 (ET-1) contributes to the development of graft arteriosclerosis and whether the orally active nonpeptide endothelin receptor antagonist bosentan, which blocks both ETA and ETB receptors, can protect against this pathologic damage. METHODS AND RESULTS: Recipient male Lewis rats were divided into three groups; group 1 received heterotopic heart transplantations from Lewis donors and groups 2 and 3 received transplantations from Brown-Norway donors; group 3 recipients also received bosentan orally at the dose of 20 mg/kg per day for 120 days. All recipients were given cyclosporine and were euthanized at examination 120 days after transplantation. Plasma ET-1 levels were significantly higher in group 2 than in group 1 (6.99+/-0.91 and 4.15+/-.83 pg/mL, respectively). Strong ET-1 immunoreactivity was seen in both the thickened neointima and the media of the coronary arteries in group 2 but not in group 1. The mean ratio of the coronary luminal area to the total vascular area in group 2 (19.0+/-11.7%) was significantly lower than that in group 1 (34.2+/-9.9%) and was significantly increased in group 3 (33.2+/-9.2%). CONCLUSIONS: These results show that local upregulation of ET-1, mainly in the thickened neointima and the media of the coronary arteries, may play an important role in the pathogenesis of graft arteriosclerosis by stimulating ETA receptors, ETB receptors, or both. Orally active bosentan might be a useful agent for the clinical prevention of graft arteriosclerosis.     

Microwave Power Dependence of Surface Resistance of High-Temperature Superconductor YBa2Cu3O y Films by Dielectric Resonator Method

The microwave power dependence of the surface resistance of YBa₂Cu₃O_y films of two different surface morphologies was measured using the dielectric resonator method. The dielectric resonator consisted of a high-quality sapphire rod sandwiched between two superconductor films. Measurements showed that the microwave power dependence of the surface resistance strongly depended on the surface morphology of the YBa₂Cu₃O_y film though the surface resistance of those films at low microwave power was comparable. In conclusion, the surface morphology is one of the reasons of the power dependence which is crucial for high power applications.     

High-speed VCSEL of modulation bandwidth over 7.0 GHz and itsapplication to 100 m PCF datalink

High-speed vertical cavity surface emitting laser (VCSEL) with 6×6 μm active area is fabricated by reducing its pad area in order to reduce its parasitic capacitance. The fabricated VCSEL shows the 3 dB bandwidth of over 7 GHz and average threshold current of 0.7 mA. This is the highest 3 dB modulation bandwidth ever reported for the plan type bottom emitted laser with pad. The maximum intrinsic bandwidth as estimated from k-factor is found to be over 20 GHz, which is less than three times than the observed bandwidth. The thermal characteristics are also found to be almost unchanged due to the reducing of its pad size. It also showed open eye pattern for 3 GHz nonreturn to zero (NRZ) pseudorandom signal after transmission through 100 m large core plastic clad fiber (PCF), which could be used in short and medium distance optical links