Development of Small Drop-Weight Testing Machine Based on Electromagnetic Induction

Experimental Mechanics - The impact strengths of solder joints between an electrical substrate and millimeter- or micrometer-sized electrical components such as resistors and capacitors must be...     

Asymptotic completeness for long-range many-particle systems with Stark effect. II

We prove the existence and the asymptotic completeness of the Dollard-type modified wave operators for many-particle Stark Hamiltonians with long-range potentials.     

Current spreading effects in 680-nm-band self-sustained pulsating AlGalnP visible laser diodes

We have developed 680-nm-band AlGalnP visible laser diodes having very lowintensity noise with stable self-sustained pulsation. The pulsation characteristics were affected by current spreading outside the ridge stripe. We obtained AlGalnP visible laser diodes with stable self-sustained pulsation by optimizing the ridge structure. The lasers achieved relative intensity noise (RIN) as low as-136 dB Hz^–1 in the temperature range 20–50°C at 3 mW.     

Direct mono-phosphorylation of 1,3-diols. A synthesis of FTY720-phosphate

A novel method for selective and direct phosphorylation of various 1,3-diols using silver(I) oxide, tetrabenzyl pyrophosphate (TBPP), and tetrahexylammonium iodide affording mono-phosphates was developed. We applied the present method to the synthesis of FTY720-phosphate.     

Nanoparticle Formation Mechanism in CVD Reactor with Ionization of Source Vapor

A new chemical vapor deposition (CVD) method, called ionization CVD, was developed, to produce non-agglomerated nanoparticles in which reactant gases are charged. A sonic-jet corona discharger was used as an ionizer in the developed nanoparticle generator. For a tetraethylorthosilicate (TEOS)/O₂ chemical system, SiO₂ nanoparticles were prepared. All particles formed by the ionization CVD were charged unipolarly. SEM micrographs of particles showed that the repulsive Coulombic force between charged particles reduces their coagulation rate and produces non-agglomerated nanoparticles that have a relatively high number concentration and small size. An external field was used to collect the charged particles onto Si wafers. These collected samples indicated that the deposition of charged particles could be controlled by the external electric field. Particle concentration measurement with a condensation nucleus counter at various TEOS concentrations suggested the particle formation mechanism in the ionization CVD was an ion-induced nucleation.     

Phase transition in dilute solution of poly(γ-benzyl-L-glutamate) in dichloromethane at a low temperature

The dielectric constant of solutions of poly(γ-benzyl-L -glutamate) (PBLG) in dichloromethane shows a jump near 195°K, irrespective of frequency. Therefore, the discontinuity is not a dispersion phenomenon but a phase transition in the thermodynamic sense. The transition temperature is independent of the concentration in the range from 0.01 to 10% by weight, but it increases linearly with the logarithm of the molecular weight of PBLG. The height of the jump depends strongly on frequency, concentration, and molecular weight. The viscosity also changes abruptly at 195°K. These results suggest that the PBLG molecule forms a cluster like a liquid crystal or is in a random coil state below the transition point.     

Calculation of absorption coefficient for the ν2 and ν3 bands of sulfur dioxide

Absorption coefficients S/d of sulfur dioxide were calculated in the ν₂ and ν₃ bands for a temperature range from 300 to 1200°K. Calculations were carried out for such vibrational transitions that their integrated absorption coefficients α at T°K are greater than 0.1% of the total integrated absorption coefficients α^obs observed at 300°K. Rotational lines with intensities greater than 10^-6 cm^-2 atm^-1 STP were included in the calculation. The line intensities were averaged over small wavenumber intervals of Δω = 10 cm^-1 throughout the bands to obtain the absorption coefficients S/d. They were compared with the experimental values of other investigators and good agreement was obtained.     

Yb (Ba, Sr)2Cu4O8: a “124” phase superconductor with a reduced unit cell volume

Yb(Ba_1−xSr_x)₂Cu₄O₈ (0.1x0.3) superconductors of the YBa₂Cu₄O₈(“124”) structure were successfully synthesized using an O₂-hot-isostaticc-pressing (HIP) technique. The samples were characterized with respect to the crystal structure and superconducting properties. The lattice parameters of the samples decreased as the substitution of Sr for Ba proceeded. The superconducting transition temperatures of all the Yb-“124” samples were more or less the same, being around 80 K.     

Polarization memory of luminescence from photo-generated carriers in aSixC1−x:H (x∼0.2)

Photoluminescence of aSi_xC_1?x:H (x～0.2) is studied with a particular interest on the localization of carriers. Taking the polarization memory of luminescence as a probe, we clarify the localized character of photo-generated carriers as functions of excitation photon energy, emitted photon energy, temperature and time. The picosecond time-resolved measurement of the polarization memory is shown useful to study dynamical relaxation processes of carriers in disordered systems.     

Low-lying states in112In

Low-lying states below 500 keV excitation in¹¹²In have been investigated via the¹¹²Cd(p, nγ) reaction. New levels have been established atE ^x=206.5keV and 456.1 keV from the measuredγ-ray excitation functions,γ?γ coincidences and the precision measurements of the (p, n) threshold energy of the ground state and of the 206.5 keV state of¹¹²In. Spins and parities of the 206.5 keV state (2⁺) and the 456.1 keV state (3⁺) and multipolarities and mixing ratios of the deexcitationγ-rays have been determined from the angular distributions and linear polarizations of the deexcitation γ-rays as well as the excitation functions of the residual levels. Possible configurations of the newly-found levels are discussed. Half-lives of two states have been remeasured:T _1/2=15.2±0.1 min for the ground state andT _1/2=20.9±0.1 min for the 156.4 keV (4⁺) state. The ground stateQ-value for the¹¹²Cd(p, n)¹¹² In reaction has been measured to be ?3.376±0.006 MeV.