Improvement of the superconducting magnetic levitation system forthe determination of the magnetic flux quantum

An improvement of the preliminary superconducting magnetic levitation system for the absolute determination of the magnetic flux quantum is described. This improvement includes the development of the flux-up method to determine the flux in terms of the Josephson voltage. The improvement is essential for the determination of the magnetic flux quantum as well as of the coil current, in terms of the Josephson voltage and quantized Hall resistance     

Characterization of high-density polyethylene prepared at low pressure

A high-density polyethylene prepared at low pressures is characterized with respect to density, microscopic examination, mechanical properties, and diffusion. The data for the slowly cooled, nonisothermally crystallized polymer clearly indicate that the method of preparation grossly affects the final properties of the polymer.     

Dynamics of dissolved oxygen during algal bloom in Lake Kasumigaura, Japan

Dynamics of dissolved oxygen during an algal bloom were studied in Lake Kasumigaura. Great amounts of oxygen arose from photosynthesis, and the concentration of dissolved oxygen reached 190% of saturation at 12 h. The majority of the dissolved oxygen produced was liberated into the atmosphere or consumed by microorganisms. Only minor fractions were transported into the dysphotic zone due to the low eddy diffusion coefficient in deeper waters of the euphotic zone.     

Synthesis and photo-electrochemical properties of novel thienopyrazine and quinoxaline derivatives,and their dye-sensitized solar cell performance

Light absorption from visible to NIR region is required to increase the photocurrent and to enhance the photo-energy conversion efficiencies in dye-sensitized solar cells (DSSCs). We have now developed novel thienopyrazine dye TP1 which has absorption up to 700 nm. Quinoxaline dye QX2 with absorption at shorter wavelengths than TP1 has been synthesized for comparisons. The power conversion efficiencies of DSSCs with TP1 and QX2 showed 4.4% and 3.2%, respectively. The absorption edge in IPCE of TP1 reached 800 nm and the open circuit voltage (Voc) of QX2 was high (0.77 V). To improve the device performances, QX2 was used as a co-adsorbent dye with TP1. In the mixed sensitizer based DSSC, a high power conversion efficiency of 6.2% was achieved due to the effective light harvesting and steric effect of QX2.     

Oxidation of titanium beryllide fabricated by plasma-sintering method

It is imperative to establish the blanket technologies for realization of D-T fusion reactors. The neutron multiplier in the fusion reactor blankets plays one of the key roles with regard to breeding of tritium. Metallic beryllium has been considered as a primary candidate for the neutron multiplier, but it is highly reactive with water vapor and oxygen at high temperatures producing H₂ and BeO. Thus, it is necessary to develop more advanced neutron multipliers that are more chemically stable than metallic beryllium. One of the intermetallic compounds of beryllium and titanium, Be₁₂Ti, possesses high tolerance to water vapor and oxygen, low swelling property, and better compatibility with structural materials. Thus, it could be an alternative of metallic beryllium. However, few experimental data are available for this material, and thus more experimental studies need to be performed to evaluate its performance as a neutron multiplier. In this study, a Be₁₂Ti sample was fabricated by a new production route, plasma-sintering method, and of which reactivity with O₂ and H₂O was examined. Experimental results suggest that the Be₁₂Ti sample prepared by the new production route possesses high resistance to oxidation by O₂ and H₂O.     

Effect of composition and stereoregularity on phase-transition behavior of aqueous N-ethylacrylamide/N-n-propylacrylamide copolymer solutions

Radical copolymerizations of N-ethylacrylamide and N-n-propylacrylamide (NNPAAm) at various ratios were carried out at −40 °C, in toluene in the presence of 3-methyl-3-pentanol, or in N-ethylacetamide. Syndiotactic-rich copolymers with racemo diad contents of 67.1–70.2%, and isotactic-rich copolymers with meso diad contents of 60.9–64.5% were prepared. Syndiotactic-rich copolymers with NNPAAm compositions of ≥92.9 mol% exhibited large hystereses in the phase-transition temperatures of their aqueous solutions. Isotactic-rich copolymers with NNPAAm compositions of 39.2–67.6 mol% exhibited large hystereses in the phase-transition temperatures of their aqueous solutions. Those of composition >67.6 mol% were insoluble in water. Stereosequence analysis suggested that isotactic sequences favored intramolecular hydrogen bonding between contiguous NNPAAm units, more than syndiotactic sequences. Enhanced intramolecular hydrogen bonding in isotactic sequences was responsible for the large hystereses and insolubility of isotactic-rich copolymers with high NNPAAm compositions.     

Versatility of photoalignment techniques: From nematics to a wide range of functional materials

Alignment methods of nematic liquid crystals (LCs) by surface photoreactions on substrate surfaces were initially proposed around 1990, and the photoalignment technology of nematic LCs has recently been integrated into the LC device fabrication industry due to its profitable features. Accumulated efforts in this field have revealed that applications of photoalignment processes are not limited to conventional nematic LCs but that a variety of functional materials can also be manipulated according to this principle. Target materials have now been extended to thermotropic smectic LCs, discotic LCs, LC polymers, block copolymers, gel networks, conjugated polymers, and organic semiconductors and lyotropic systems including chromonic LCs and inorganic–organic mesostructured hybrids. Through these photochemical approaches, many types of photopatterning for both topographical and orientational modulations have become feasible. This article reviews photoalignment processes applied to a wide range of materials, surveying relatively recent work. Some important related alignment and patterning processes are also introduced to clarify the significance of these photoalignment techniques.     

Isolation and characterization of Candida albicans homologue of RAP1, a repressor and activator protein gene in Saccharomyces cerevisiae

To study the function of RAP1, a Candida albicans gene (CaRAP1) that shows sequence similarity to RAP1 of Saccharomyces cerevisiae was isolated by colony hybridization. DNA sequencing predicted an open reading frame of 429 amino acids with an overall identity of 24% to the ScRap1p. The DNA binding domain (DBD) was highly conserved, and EMSA using a GST-CaRap1p fusion protein confirmed its binding ability to the RPG-box of S. cerevisiae ENO1. In contrast, the N-terminus was less conserved and a moderate homology was observed in the BRCT domain. Interestingly, CaRap1p did not contain the C-terminal activation/repression region of ScRap1p.