Recrystallization of TiC dispersion Mo-alloy

The recrystallization of Mo sheet which was mechanically alloyed with 1.0 TiC and 0.2 C (weight %) was investigated in H₂ atmosphere. The change in hardness (Hv) was measured as a function of annealing temperature and the microstructure was observed using scanning, transmission and Auger electron microscopy. Hv decreased slowly below 1800 °C and steeply above 1800 °C. Dislocations and grain boundaries were still pinned by small Ti-oxy-carbide and/or Ti-oxide particles even at 1800 °C, while the grain size increased. Above 1800 °C, however, such particles were coarsened with the formation of pores and also the grain size increased further. As a result, the slow drop phenomena of Hv below 1800 °C should be interpreted in terms of a retarding effect of fine particles on the recrystallization. The prominent drop phenomena of Hv over 1800 °C can be understood by the grain growth and particle coarsening accompanying an evolution of pores.     

High efficiency a-Si//poly-Si tandem solar cell

A series of experimental trials has been carried out to realize the high efficiency a-Si//Poly-Si tandem solar cell. Employing p-type μc-SiC as a wide-gap heterojunction window, a-SiC as an interface buffer layer and n-type μc-Si as a back ohmic contact layer, 17.2 percent conversion efficiency has been achieved with the structure of ITO/p μc-SiC/n Poly-Si/n μc-Si heterojunction. Utilizing an optically transparent a-Si p-i-n cell as a top cell and inserting an optical coupler between the top and the Poly-Si bottom cell, a high total efficiency of 21.0 percent has been obtained so far on the four-terminal tandem cell. This conversion efficiency value represents a world record for a-Si basis tandem solar cells.     

Monolayer formation of chitin derivatives containing PMMA side-chains

The monolayer behaviour of poly(methyl methacrylate) (PMMA)-grafted chitin derivatives was studied on an air–water interface by measuring surface pressure–area isotherms. The formation of a stable monolayer indicates the well-defined packing and orientation of the chitin derivative, which can be regulated by the main-chain length under appropriate experimental conditions. The isotherms exhibit a transition point from a liquid expanded phase to a condensed phase at a surface pressure of approximately 15mN/m for almost all monolayers examined. The transition pressure decreases with increase of temperature from 10 to 20°C. The properties of the sub-phase affected the formation of a monolayer greatly. The collapse of a surface film takes place at lower pressure on the sub-phase of a 0.1 M NaCI solution. After introducing lysozyme at a concentration at 2.4 × 10^?8M to the sub-phase, the monolayer showed an extensively expanded phase with a longer transition region. This indicates that the monolayer was degraded by the lysozyme, resulting in a disordered structure. The results are contrasted with those of an aqueous phase where N-acetylglucosamine residues may be inaccessible to lysozyme so that the degradation of the chitin derivative occurs at a very slow rate.     

Synthesis and properties of poly(diphenylacetylenes) having ether linkages

Summary Polymerization of 1-phenyl-2-(p-phenoxyphenyl)acetylene (p-PhODPA), 1-phenyl-2-(p-methoxyphenyl)acetylene, and 1-phenyl-2-(p-n-butoxyphenyl)acetylene was examined. These monomers polymerized with TaCl₅-n-Bu₄Sn to give methanol-insoluble polymers in over 60% yields. Poly(p-PhODPA) was a yellow solid completely soluble in toluene, CHCl₃, etc., and its weight-average molecular weight was about 1.0x10⁶ or higher. This polymer was thermally very stable (the onset temperature of weight loss in TGA in air was 420 °C). Its oxygen permeability coefficient (P o ₂) was 37 barrers (P o ₂/P n ₂ 2.2) and similar to that of natural rubber. In contrast, the other two polymers did not completely dissolve in any organic solvent, and their thermal stability was lower.     

Characterizing the effect of substrate surface roughness on particle-wall interaction with the airflow method

The effect of surface roughness on particle-wall interaction was studied by the airflow method. Five kinds of monodispersed spherical particles (D_p50 = 11-41 μm) and six test pieces with different surface roughness (Ra = 0.01-1.64 μm) were used in the experiments. The particles were dispersed on the test pieces to form a monolayer, and entrained in a rectangular air channel. The air velocity increased at a constant rate, and the entrained particles were detected with a laser dust monitor. Microscopic observations showed that particle entrainment occurred in discrete and intermittent events during experiment, thus a statistical parameter, i.e. the particle entrainment efficiency as a function of the air velocity, was defined for evaluating the particle-wall interaction force distribution. The experimental results showed that the air velocity for particle entrainment decreases with the increase of the surface roughness within submicron-scale and reaches a lower limit, while increases to some extent for micron-scale surface roughness. It was also found that the effect of the substrate surface roughness depends on the particle diameter.     

Overview Paper: Intelligent color imaging*

Abstract— With the 600th anniversary of Johann Gutenberg's birth in 2000 A.D., we should look back at the historical significance of letterpress technology and take a step forward into the new age of color imaging. Currently, digital‐imaging technology plays a leading role in visual communications, but meets severe challenges to satisfy human vision. It is essential to consider what human vision “sees” in order to capture, store, transmit, and reproduce a truly realistic image just as human vision. Advances not only in high‐precision and high‐definition digital media but also in intelligent image‐processing technologies will be helpful in producing more aesthetic and pleasant imaging. This paper briefly introduces “intelligent” processing towards that goal by using region‐based spatially variant, and scene‐referred approaches.     

Physiological causes of individual variations in color-matching functions

The present study confirms that the individual variations of Stiles' 20 color-matching functions are physiologically well predicted by those of eye lens and macular optical densities. The principal-component analysis of the blue color-matching functions shows the significance of the two independent spectral components, which are expected to correspond to lens and macular optical densities. The lens and the macular densities for each of Stiles' 20 observers are estimated by using their published data physiologically measured. The estimated densities predict well each of Stiles' 20 color-matching functions. The singular-value decomposition of the estimated 20 color-matching functions provides a good estimate of the standard-deviate observer derived from the original Stiles 20 color-matching functions by using the same procedure.     

Enhancement of Electrical Conduction in ZnO by CoO Doping

Electrical conductivity of sintered ZnO was increased at high temperatures by CoO doping. Thermoelectric power measurements confirmed that ZnO doped with CoO was still an n-type semiconductor. Temperature-independent behavior of the carrier density was observed.     

Pradimicins T1 and T2, new antifungal antibiotics produced by an actinomycete. I. Taxonomy, production, isolation, physico-chemical and biological properties

Pradimicins T1 and T2, new members of the pradimicin family of antibiotics, were produced by an actinomycete strain AA3798. Pradimicin T1 exhibited potent activity against a wide spectrum of fungi in vitro and demonstrated efficacy against systemic Candida albicans and Aspergillus fumigatus infections in mice.