New type of tin support for hydroprocessing catalyst

TiN supported molybdenum sulfide catalysts showed much higher activity for cleavage of C-C bonds than oxide supported molybdenum sulfide catalysts, indicating the possibility of a new generation of supports for hydroprocessing catalysts.     

Frequency shift of a GaAlAs diode laser in a magnetic field

The oscillation frequency shift of a GaAlAs diode laser under a magnetic field at room temperature is reported. In this experiment the observed frequency shift is 500 MHz to the low-frequency side at the magnetic flux density of 1.4 T, and shows the quadratic dependence on the magnetic flux density.     

IR reflection spectra of the silicate surface layer of yellowed rice plant leaf

We have investigated the IR reflectional properties of the three-hold cytrogical surface layer (kutchikura layer on silicate layer n(SiO₂) on silicate cellulose layer C₆H₁₀Si_xO_y) and that of chlorophyll, a(C₅₅H₇₂M_gN₄O₅) etc., present in bladder's cells by using our experimental method. From analysis of three set of anisotropical reflection spectra assigned as due to CO, SiO and NC surface oscillators contained in the cytrogical cells and measured at 2500 2200 cm^?1, 1200 700 cm^?1 and at 700 200 cm^?1 regions, we have confirmed some important results. One is their quantized directional distributions that of the numbers of fine step spectrum and that of the reflection integrals of these spectra. Here, that of the NC oscillators were found to distribute in pentagonal directions relating to the molecular structure of chlorophyll. Second, we confirmed the pecularity of eight fine step-series measured in these sensitive spectra comparing with that of bamboo's seven series. Third, from analysis of the stepnized variation of the “reflection integrals”, we estimated the origin of this effect as which is presumably due to statistical, transfer of the 2p₄ valence electrons etc. in the oxygen atoms from C=O, Si=O double bonding side upto the shallower quantized states, E(N,J) which were formed softly around the and surface oscillators. And these surface oscillators were confirmed as to make photo-chemical reaction process by receiving energy higher than ～24 m eV especially under the illumination of sunshine etc.     

Field test results of multi-channel digital tv transmission at 15 and 30 Mb/s through an intelsat satellite using a PSK/FDMA system

This paper describes field test results of multi-channel digital TV transmission using a PSK/FDMA system and the related subjective test results of received TV pictures. The picture quality of the multi-channel 15 or 30 Mb/s transmission for both NTSC and PAL systems through the INTELSAT POR satellite are subjectively evaluated for various bit-error rates. In addition, subjective evaluations were made at various values of earth-station e.i.r.p. to compare the picture quality of digital transmissions with that of current half-transponder FM transmission.     

Synthesis and Characterization of a SiAION Glass

Homogeneous SiAION glasses containing up to 1 wt% nitrogen were synthesized via a pressureless method with a controlled quench rate and structurally investigated using ²⁷Al and ²⁹Si magic-angle spinning nuclear magnetic resonance (MAS NMR), Raman, and infrared (IR) spectroscopies. Minor changes occur with the incorporation of nitrogen into the aluminosilicate glass structure as evidenced by modifications to spectra of a nitrogen-free aluminosilicate glass. The ²⁷Al MAS NMR spectrum of the SiAION glass shows the existence of aluminum in 4-,5-, and 6-coordination to oxygen. The ²⁹Si MAS NMR spectra show a distribution of silicon sites in 4-coordination to oxygen. Raman and IR spectra of the SiAION glass show additional features due to incorporation of nitrogen in the structure compared with spectra of nitrogen-free aluminosilicate glasses.     

Strength Analysis of Yttria-Stabilized Tetragonal Zirconia Polycrystals

Tensile strength of Y₂O₃-stabilized ZrO₂ polycrystals (Y-TZP) was measured by a newly developed tensile testing method with a rectangular bar. The tensile strength of Y-TZP was lower than that of the three-point bend strength, and the shape of the tensile strength distribution was quite different from that of the three-point bend strength distribution. It was difficult to predict the distribution curve of the tensile strength using the data of the three-point bend strength by one-modal Weibull distribution. The distribution of the tensile strength was analyzed by two- or three-model Weibull distribution coupled with an analysis of fracture origins. The distribution curve of the three-point bend strength which was estimated by multimodal Weibull distribution agreed favorably with that of the measured three-point bend strength values. A two-modal Weibull distribution function was formulated approximately from the distributions of the tensile and three-point bend strengths, and the estimated two-modal Weibull distribution function for the four-point bend strength agreed well with the measured four-point bend strength.     

Sedimentation study on the binding of fibrinogen or of antithrombin III with acidic polysaccharides including heparin

Summary The binding of fibrinogen with heparin and dextran sulfates, and of antithrombin III with heparin and dextran sulfate were investigated by sedimentation velocity method. From the measurement of fibrinogen-acidic polysaccharide systems, it was confirmed that heparin and low molecular weight dextran sulfate(DSC) forms soluble complexes with fibrinogen, though the amount bound of the latter was rather small compared with high molecular weight dextran sulfate(DSD). Antithrombin III was also found to be bound by heparin and DSC. The numbers of heparin molecules bound to one molecule of fibrinogen and antithrombin III were estimated to be 4.2 and 0.3, respectively.     

Intensity fluctuation in semiconductor lasers coupled to external cavity

Broad peaks are observed in the intensity noise spectrum for external cavity AlGaAs lasers. Oscillating longitudinal mode spectrum measured with a high resolution Fabry-Perot interferometer indicates that the intensity noise peaks result from the lasing of several closely spaced external cavity modes. A new mechanism is proposed to explain the observed noise spectrum; the intensity fluctuation is induced by modulation of the dielectric constant in the semiconductor cavity due to the beating of the electric fields for lasing modes. Qualitative agreements between the theory and experiments are obtained.     

Theoretical analysis of longitudinal mode coupling in external cavity semiconductor lasers

The single longitudinal mode behavior in long external cavity semiconductor lasers is discussed. Experimentally, the laser exhibits a single frequency oscillation even for an external cavity length of 100 cm. The mode selectivity of a composite cavity is shown to be insufficient to explain the experiments. Longitudinal mode coupling in semiconductor lasers is found to arise from an interference effect between the modes on the interband transition probability of electrons. Mode coupling equations are derived, which indicates that the single mode oscillation in long external cavity semiconductor lasers is brought about when the coupling strength goes beyond a critical value. It is shown that the effect of the hole burning in the external cavity semiconductor lasers is similar to that in the solitary laser.     

Fiber Optic Analog--Digital Hybrid Signal Transmission Employing Frequency Modulation

Investigations are carried out on the SNR performance in fiber optic FM transmission systems which use multimode fibers and 1.3 μm laser diodes. Both laser diode noise and modal noise are quantitatively evaluated in systems with and without employing a superimposed pulse modulation scheme. Based on these investigations, parameters for analog-digital hybrid signal transmission systems employing FM are determined. The hybrid signal consists of audio, video, and 2 Mbit/s digital data. The results obtained in transmission experiments satisfied the design objectives and confirmed the technical feasibility of an analog-digital hybrid transmission employing FM. The obtained results make the fiber optic FM transmission system with a 1.3mumLD an attractive alternative in subscriber systems, and video transmission systems for microwave IF links and CATV trunks.