Subscriber optical fiber cable transfer splicing system usingmechanically transferable connectors

An optical fiber cable transfer splicing system is developed for use in removing or changing optical fiber cables. The system enables rapid transfer from existing optical fiber cables to newly installed ones. The transfer is carried out synchronously using two mechanically transferable connectors which terminate the optical fiber cables at two different points, such as manholes. Before the transfer splicing, the system identifies a fiber ribbon in order to avoid mistransfer. A transfer time of less than 30 ms was achieved. The fiber ribbon was identified with a loss, from an identification light source to an identification point, of 35.5 dB. With this system, cable transfer can be faultlessly carried out with only a slight interruption to working transmission systems and circuit quality degradation is suppressed     

Basic study on neutronics of future neutron source based on accelerator driven subcritical reactor concept in Kyoto University Research Reactor Institute (KURRI)

A basic study on the nuclear characteristics in the accelerator driven subcritical reactor (ADSR) was performed through a series of neutronics design calculations and reactor physics experiments. Calculations were executed mainly by the MCNPX code, and experiments were performed at the Kyoto University Critical Assembly (KUCA). Some nuclear features of the research reactor type ADSR were revealed through the present study. The following facts were found: 1) Further studies are necessary concerning the nuclear data in the high energy region and the generated neutrons through the spallation reactions especially by the light nuclei and the lower energy protons. 2) The adjustment of subcriticality by the control rod significantly affects the reactor power of ADSR because of the distortion in the neutron flux distribution caused by the control rod insertion. 3) An accurate calculation is essential to evaluate the neutron multiplication in the ADSR. 4) The neutronics behavior after a pulse injection can be approximately simulated by the calculation.     

Temperature dependence of current-voltage characteristics of polycrystalline diamond FETs: modelling and experiment

For the first time, a theoretical model for polycrystalline diamond (PCD) field effect transistors is proposed. The model is accompanied by an investigation of the single crystalline diamond (SCD) FET for the verification of material parameters employed in the simulation. The model runs on a device simulator, PISCES-IIB, and correctly accounts for the temperature-dependent shift of the I–V characteristics from pentode-like to triode-like behaviour as well as the temperature dependent pinch-off and saturation. Agreement between simulated and measured currents is obtained with a higher value of the activation energy for the dopant in PCD than in SCD, as has been reported for silicon.     

Graded-gap a-SiC:H p-i-n thin-film light-emitting diodes

To improve the performance of hydrogenated amorphous-silicon carbide (a-SiC:H) p-i-n thin-film light-emitting diodes (TFLEDs), a p-i-n TFLED with a graded p-i junction was proposed and fabricated. The electroluminescence (EL) intensity of the proposed TFLED was more than 100 times higher than that of the basic p-i-n TFLED and about 35 times lower than that of the conventional green LED, at the same injection current density. This significant improvement is attributed to the better interface property and enhancement of hole injection efficiency by using the graded-gap p-i junction     

Plastic buckling analysis of a circular cylinder considering plastic compressibility

In this study the plastic buckling analysis of a circular cylinder under axial compression is carried out considering plastic compressibility. For the stability analysis, the linearized finite element equation is derived and the general elastic-plastic constitutive equation is formulated. The Drucker-Prager plastic potential is used to describe the plastic compressible yielding and the strength-differential effect. The influence of plastic compressibility on the buckling load is investigated for a circular cylinder.     

Synthesis and properties of some novel,soluble and light‐coloured,aromatic poly(amide–imide) copolymers

A new type of tetraimide‐dicarboxylic acid (I) was synthesized starting from the ring‐opening addition of m‐aminobenzoic acid (m‐ABA), 4,4′‐oxydiphthalic anhydride (ODPA) and 4,4′‐methylenedianiline (MDA) at a 2:2:1 molar ratio in N‐methyl‐2‐pyrrolidone (NMP), followed by cyclodehydration to the diacid I. A series of soluble and light‐coloured poly(amide–imide–imide)s (III_a–j) was prepared by triphenyl phosphite‐activated polycondensation from the tetraimide‐diacid I with various aromatic diamines (II_a–j). All films cast from DMAc had cutoff wavelengths shorter than 400 nm (376–393 nm) and had b* values between 20.46 and 40.67; these polymers were much lighter in colour than those of the corresponding trimellitimide series. All polymers were readily soluble in a variety of organic solvents such as NMP, N,N‐dimethylacetamide, dimethyl sulfoxide, and even in the less polar m‐cresol and pyridine. Compared with those of corresponding ODPA–MDA polyimide, the solubilities of poly(amide–imide–imide)s III_a–j were greatly improved. Polymers III_a–j afforded tough, transparent, and flexible films, which had tensile strengths ranging from 82 to 105 MPa, elongations at break from 8 to 14%, and initial moduli from 2.0 to 2.2 GPa. The glass transition temperature of polymers were recorded at 255–288 °C. They had 10% weight loss at a temperature above 540 °C and left more than 60% residue even at 800 °C in nitrogen. © 2002 Society of Chemical Industry     

Neurotrophic activity of organosulfur compounds having a thioallyl group on cultured rat hippocampal neurons

Several organosulfur compounds found in garlic extract promoted the survival of rat hippocampal neurons in vitro. From the analysis of structure-activity relationship, thioallyl group in these compounds is essential for the manifestation of neurotrophic activity. S-Allyl-L-cysteine (SAC), one of the organosulfur compounds having thioallyl group in garlic extract, also promoted the axonal branching of cultured neurons. These results suggest that thioallyl compounds make a unique group of neurotrophic factors.