High-field properties of n-InP under high pressure

The high electric field properties of n-InP at 300 K have been studied as a function of pressure. Hydrostatic measurements are made in a piston and cylinder apparatus, using a liquid pressure-transmitting medium. The threshold fields (E_T) for transferred electron instabilities range from 7.5 to 8.5 kV/cm at atmospheric pressure. The resistivity of the samples increases with increasing pressure. The most reliable results show that E_T increases slightly with pressure below 40 kbar. This behavior can be explained qualitatively in terms of possible band structure changes. By using known variations of parameters such as effective mass and sub-band energy gaps, detailed theoretical calculations are carried out to fit the data and to determine the correct mode of operation (two- or three-level operation). The results are also compared with analogous experiments on GaAs.     

Electrode reaction of silver on a silver bromide crystal

The electrode reactions of silver on a silver bromide single crystal were observed employing a current step method with a small amount of electricity passed. Special attention was paid to the preparation of the electrode contact. From the overvoltage change, the kinetic parameters, i_O, Fv and a_O were obtained in the temperature range 300–400°C. It is concluded that the reactions proceed with two steps, the one is a formation of interfacial silver ions, through a charge transfer process and the other the incorporation of the formed ion into the electrolyte crystal, which is a specific character for the solid electrolyte system. In this system, the iterfacial silver ion seems to be incorporated through a vacant site of lattice with an accompanying surface diffusion.     

Fluorescence and oscillation characteristics of LiNdP4O12lasers at 1.317 µm

Spectroscopic data and laser oscillation characteristics of the 1.317 μ line in lithium neodymium tetraphosphate (LNP) are reported. A stimulated emission cross section of this transition was spectroscopically determined as7.1 times 10^{-20}cm², which corresponds to 1/4.5 of that at the 1.047-μm transition. Cross-section temperature dependence, laser cavity loss, threshold versus crystal length, and threshold temperature dependence were measured experimentally. Since resonant loss was negligible at the 1.317 μm line, room temperature threshold is lower than that at 1.047-μm in the case of long crystal, and threshold temperature dependence is weaker than that at 1.047 μm. A miniaturized LNP laser, using a graded index fiber as a focusing medium, is also shown. LED pump intensity required to obtain a constant output is compared for 1.047- and 1.317-μm wavelengths. The 1.317-μm line seems to be useful as miniaturized optical sources in optical communication systems, since required intensity is around several W/cm²for the side pump, and the wavelength corresponds to the most transparent band of ultra low-loss optical fibers.     

Automatic welding of pipeline in Japan: Part 1—Some experiences with site applications

Recent experiments on automatic welding of pipeline in Japan have been based on the short-arc welding process and aimed at reducing the welding time by $\text{v}\text{?}$arying the welding conditions and by effecting improvements to the welding equipment.The short-arc process has been employed increasingly in the actual pipeline installation work, exhibiting a number of advantages such as stabilisation of both the quality of weld and the welding time. However, it has presented various problems, including the difficulty in jointing one elbow with another or with a cut pipe and the applicability to a narrow work site.For automatic welding of large diameter pipes for water and town gas supply, on the other hand, the electro gas process has enjoyed a broadened expanse of application by virtue of its high productivity.Further, the pulsed TIG process by programmed control was applied experimentally and produced successful results in the laying of pipe type cable pipeline.     

Insect haemolymph exo-beta-N-acetylglucosaminidase from Bombyx mori. Purification and properties

Haemolymph exo-beta-N-acetylglucosaminidase from the silkworm, Bombyx mori was purified to homogeneity as shown by disc-electrophoresis and ultracentrifugation. It appeared to be composed of two identical subunits of 61 000 molecular weight, which were obtained by sodium dodecyl sulfate-electrophoresis. The purified enzyme was capable of hydrolyzing phenyl N-acetyl-beta-D-glucosaminide, phenyl N-acetyl-beta-D-galactosaminide and N N'-diacetylchitobiose in the relative ratios 100:20:3. The enzyme was found to be a glycoprotein containing about 4% of neutral sugar.