Bidirectional finite-element method-of-line beam propagation method(FE-MoL-BPM) for analyzing optical waveguides with discontinuities

A bidirectional finite-element method-of-line beam propagation method (FE-MoL-BPM) is newly proposed for analyzing optical waveguides with discontinuities including transmissions, reflections and radiations. In this approach, the finite-element method (FEM) is introduced to discretize the derivatives of the variable perpendicular to the propagation direction. Since the proposed method is accurate and stable, only a small number of nodal points are required     

Large aperture superconducting magnet (benkei)

Benkei, which was a large window frame conventional magnet at KEK has been converted to a superconducting magnet. In the conversion, the pole gap has been doubled from 0.5 m to 1.0 m retaining an analysing power at 2 T m. Several new techniques were applied to coil windings and cryostat fabrication. The superconducting Benkei has shown satisfactory performances for long term operation.     

Sequential hemodynamic activation of motor areas and the draining veins during finger movements revealed by cross-correlation between signals from fMRI

Activity in the human supplementary motor area (SMA), primary motor cortex (M1), and the draining vein of the motor cortex during a visually triggered finger opposition task was measured by functional magnetic resonance imaging with a repetition time of 1 s. Sequential hemodynamic activation in these areas was revealed by cross-correlating a signal sequence in M1 directly with signal sequences from SMA and the draining vein, and applying polynomial fitting with the aid of Akaike's information criterion. We succeeded in detecting a time delay of approximately 0.5 s between the activations of SMA and M1, and a delay of nearly 1.3 s between the activations of M1 and its draining vein. The new combination of fMRI and data analysis techniques has attained a time resolution comparable to those in preceding studies that used shorter fMRI repetition times of 100-200 ms.     

Para-aortic lymph node metastasis in carcinoma of the distal bile duct

BACKGROUND/AIMS: Lymph node dissection plays an important role in radical surgery for pancreaticoduodenal carcinomas. The aim of this study was to identify the critical areas of lymph node dissection in carcinoma of the distal bile duct. METHODOLOGY: Between January 1995 and December 1996, 20 consecutive patients with distal bile duct cancer underwent pancreaticoduodenectomy with extended lymph node dissection (including the para-aortic nodes). Histopathologic findings were examined with special reference to lymph node metastasis. RESULTS: Histological evidence of lymph node metastasis was found in 11 patients (55%). The areas with frequent metastases were the posterior pancreaticoduodenal lymph nodes (35%), and the nodes around the hepatoduodenal ligament (35%) and around the common hepatic artery (30%). Para-aortic lymph node involvement was identified in 5 patients (25%). Most of these existed in the inter-aorticocaval space. Pancreatic parenchymal invasion was present in 10 patients. Half of the patients with pancreatic invasion had para-aortic nodal involvement. Para-aortic lymph node metastasis was significantly associated with pancreatic parenchymal invasion (p<0.05). CONCLUSIONS: In carcinoma of the distal bile duct with pancreatic parenchymal invasion, extended lymph node dissection (including para-aortic nodes) should be undertaken because of the relatively high incidence of metastasis.     

0.81 ?m band AlGaAs/GaAs double-channel planar buried-heterostructure laser with large optical cavity

0.81 ?m-band AlGaAs/GaAs double-channel planar buried-heterostructure laser diodes with large optical cavity have been developed as light sources for use in analogue optical fibre communication systems. Linear light-output/current characteristics and a single-longitudinal-mode spectrum at a modulation frequency f = 100 MHz with modulation index m = 0.9 have been attained.     

Dynamic mechanical properties of photopolymerizable poly(vinyl alcohol)–acrylate monomer blends

Dynamic mechanical properties of photopolymerizable poly(vinyl alcohol) (PVA)–monoacrylate blends were investigated by measuring dynamic shear modulus G′ and loss tangent, tan δ. The dynamic mechanical properties of the blends before being exposed to UV irradiation were governed by the weight percent of the monomers which act as plasticizers. On the other hand, the UV-irradiated blends seemed to be typical two-phase materials since they revealed two tan δ maxima whose positions were independent of the monomer content. Those two maxima were assigned to PVA and photopolymerized acrylates with reference to the dynamic mechanical data of PVA and a PVA-polyacrylamide polyblend. Those dynamic mechanical data suggested that insolubilization of the blend type photopolymers should be caused by a decrease in solubility due to graft polymerization of acrylate monomers onto PVA.     

Experimental study on house cooling and heating with solar energy using flat plate collector

The OSE Project aims at developing the technology to utilize solar energy for heating, cooling and hot water supply on the basis of various technology for energy conservation in buildings. For the first step of this project a solar heating and cooling system with flat plate collectors and absorption refrigeration machine was installed in a house in 1974. This paper reports outlines of the system and operating results.