Stress tests on 1.3 ?m buried-heterostructure laser diode

Preliminary results of the accelerated aging test under stresses of temperature and current are presented. The degradation modes are found to be divided into two patterns which can be mapped in co-ordinates of these stresses.     

A possible immunosuppressant, cycloprodigiosin hydrochloride, obtained from Pseudoalteromonas denitrificans

Biochemical characteristics of spent fowl meat injected with calcium chloride or sodium chloride were evaluated. Hot-boned breast fillets were injected to 10% (wt/wt) with 0.3 M CaCl2 or 0.6 M NaCl, tumbled, and aged 24 h. Tumbling was conducted at 20 C, -635 mm Hg, 20 rpm for 1 h. Hot-boned and cold-boned (24 h) fillets were used as controls. One fillet from each carcass was baked and sheared with an Allo-Kramer cell, whereas the other fillet was used for biochemical analysis. Shear values indicated that both CaCl2- and NaCl-treated samples had significantly (P < 0.05) lower shear values than hot-boned controls but were similar (P > 0.05) to cold-boned samples. The CaCl2 injection treatment significantly elevated (P < 0.05) the tissue calcium content compared to all other treatments. There was no significant difference in heat-stable collagen content (P > 0.05) among all treatments, which indicated that CaCl2 or NaCl did not contribute to meat tenderness through degradative changes in collagen. Calpain data indicated that mu-calpain had disappeared by 24 h aging in all treatments. The m-calpain activity was significantly lower (P < 0.05) in samples treated with CaCl2 than in the other samples. The NaCl-treated samples had m-calpain activity similar (P > 0.05) to that of hot-boned controls. Sarcomeres of CaCl2-treated samples were significantly shorter (P < 0.05) than those of cold-boned controls, were similar (P > 0.05) to those of hot-boned controls, and were shorter than those of NaCl-treated muscles. The sarcomere length and calpain data suggest that CaCl2 tenderized fillets by ionic strength and calcium-specific effects (possibly a proteolytic action), whereas the NaCl solution tenderized by ionic strength effect at a similar conductivity level to that of the CaCl2 solution.     

Electron spin resonance study of Langmuir-Blodgett films of N-docosylpyridinium- di(tetracyanoquinodimethane)

An electron spin resonance (ESR) investigation is performed on Langmuir-Blodgett films consisting of a surface-active 1:2 complex of N-docosylpyridinium and tetracyanoquinodimethane (TCNQ), whose temperature-dependent spin susceptibility has been so far found to be consistent with the random-exchange Heisenberg antiferromagnetic chain (REHAC) model of Soos and Bondeson. An out-of-plane anisotropy in the ESR spectra shows that the long axes of TCNQ molecules are preferentially oriented along the plane normal to the sample, where the negligible in- plane anisotropy indicates the random distribution of the short and the pπ orbital axes in the film plane. A heat treatment applied to the samples results in an increase in the concentration of disorder, showing the possibility of controlling it in the present REHAC system.     

Optical-transmission experiment at 400 mb/s using a graded-index fibre

An optical-transmission error-rate experiment is described in which a graded-index fibre up to 5 km long is used as a transmission medium. It is shown that impairments in the transmission are mainly determined by the total frequency response of the transmission medium, including the fibre and its connection.     

Highly conducting Langmuir-Blodgett films of the TMTTF-CnTCNQ system

Highly conducting Langmuir-Blodgett (LB) films of the tetramethyltetrathia-fulvalene- alkyltetracyanoquinodimethane (TMTTF-C_n TCNQ, where C_n represents C_nH_2n+1) system are reported. The electron affinities of the acceptors C_nTCNQ (n=14, 18 or 22) in solution are almost the same and lie between those of TCNQ and dimethylTCNQ. These TCNQ derivatives form solid charge transfer complexes with TMTTF. The limiting areas of the complexes, normalized to the number of TCNQ derivatives at the air-water interface, are almost the same irrespective of the donor-to-acceptor ratio and of the length of the alkyl chain, indicating that the areas are governed by the TCNQ moiety. The monolayers of TMTTF-C_n TCNQ (n=14 or 18) are transferred onto solid substrates as LB films. Polarized UV-visible absorption spectra indicate that the long axis of TCNQ is parallel to the film surface. These LB films exhibit lateral conductivities as high as 0.4 S cm^-1 and 0.1 S cm^-1 when n=14 and n=18 respectively.     

1.5 μm transmission experiment with distributed feedback laser

The paper reports an experiment which demonstrates the possibility of error-free transmission over 100 km without repeater, by using a single-mode fiber and a laser diode with distributed feedback emitting a single longitudinal mode at the wavelength 1.5 μm.     

Pressure drop characteristics of flow in a symmetric channel with periodically expanded grooves

Pressure drop characteristics of flow in a periodically grooved channel are investigated experimentally. It is well known that a self-sustained oscillatory flow occurs from a steady-state flow at a certain critical Reynolds number in such grooved channels. The oscillatory flow enhances fluid mixing and leads to an increase in pressure drop. We measure the pressure drop with a pressure transducer. It is found that the pressure drop increases near the critical Reynolds numbers where the two- and three-dimensional oscillatory flows occur. In addition, the three-dimensional flow is confirmed by flow visualization.