Carbon Nitride Loaded with an Ultrafine,Monodisperse, Metallic Platinum-Cluster Cocatalyst for the Photocatalytic Hydrogen-Evolution Reaction

For the realization of a next-generation energy society, further improvement in the activity of water-splitting photocatalysts is essential. Platinum (Pt) is predicted to be the most effective cocatalyst for hydrogen evolution from water. However, when the number of active sites is increased by decreasing the particle size, the Pt cocatalyst is easily oxidized and thereby loses its activity. In this study, a method to load ultrafine, monodisperse, metallic Pt nanoclusters (NCs) on graphitic carbon nitride is developed, which is a promising visible-light-driven photocatalyst. In this photocatalyst, a part of the surface of the Pt NCs is protected by sulfur atoms, preventing oxidation. Consequently, the hydrogen-evolution activity per loading weight of Pt cocatalyst is significantly improved, 53 times, compared with that of a Pt-cocatalyst loaded photocatalyst by the conventional method. The developed method is also effective to enhance the overall water-splitting activity of other advanced photocatalysts such as SrTiO₃ and BaLa₄Ti₄O₁₅.     

Relocations are determined by firms' relationships with financing institutions: A paper based on network data for Japanese firms

Both theoretical and empirical research studies the factors influencing firms' location choices. This paper presents a new viewpoint by considering relationship continuity to explain small-scale relocations and relocations of small and medium-sized enterprises (SMEs), which represent the majority of firms. The influences of firms' relationships with financing institutions are studied using a two-stage nested logit model. Consequently, the positive effect of relationships on location choices is revealed and the factors preventing firms from moving are described. The model is valid for estimating relocations to medium-sized cities, and the influences on shrinking firms as opposed to expanding firms are especially strong.     

Observation of Superfluid 4He Adsorbed in One-Dimensional Mesopores

To study one-dimensional (1D) quantum liquid of ⁴ He, we measured the heat capacity and performed a torsional oscillator experiment for ⁴ He adsorbed on a new mesoporous substrate whose adsorption area consists of walls of straight one-dimensional 18Å diameter tunnels. The presence of adsorbed quantum liquid was examined by the isotope effect on the heat capacity for ³ He and ⁴ He adatoms. Above a coverage n _o , the heat capacity isotherms are completely different because of the Fermi and the Bose fluids, respectively. In the torsional oscillator experiment we observed superfluid ⁴ He above n _o . The fraction of the superfluid decoupled from the motion of the substrate is 0.13, which is the same order as 0.18 for packed Pt fine powder and 0.24 for 80 Å-porous glasses. The result indicates that the superfluid state exists in the one-dimensional ⁴ He adatoms formed in the 18 Å diameter pores.     

Construction and testing of a 3 m diameter × 5 m superconducting solenoid for the fermilab collider detector facility (CDF)

A thin 3 m diameter × 5 m, 1.5 T superconducting solenoid for the Fermilab collider detector facility (CDF solenoid) was constructed. Cool-down and excitation tests of the solenoid were carried out. The design current is 5000 A and the stored magnetic energy is 30 × 10⁶ J. The solenoid utilizes the forced flow cooling method of two-phase helium and does not have a permanent inner bobbin. The material thickness of the solenoid is 0.85 radiation length in the radial direction. An aluminum-stabilized NbTi/Cu superconductor fabricated with the EFT method was used. Radially outward magnetic forces must be supported with an outer support cylinder shrink-fitted outside the coil. The helium cooling tube of 20 mm in inner diameter and about 140 m in length was welded to the outer support cylinder.The maximum excitation current was limited to 2800 A in the present tests without an iron return yoke. Thermal response of the solenoid during the cool-down and excitation tests was very steady. A series of heater quench tests was attempted by using a heater installed at the outer support cylinder. The solenoid did not quench even for a heater input of about 10 kJ. In a warm-up test the liquid helium supply was shut off. The coil stayed superconducting for about 90 min and then the entire coil became normal very uniformly. This result is consistent with the measured heat load of the solenoid of about 35 W. The results of the present tests indicate the excellent thermal stability of the solenoid.     

Vitellogenesis-related ovary cathepsin D from Xenopus laevis: purification and properties in comparison with liver cathepsin D

Cathepsin D was purified from ovaries of Xenopus laevis by both QAE-cellulose and pepstatin-Sepharose chromatography and then characterized and compared with Xenopus liver cathepsin D. Ovary cathepsin D appeared predominantly as a 43-kilodalton (kDa) molecular mass, as revealed by SDS-polyacrylamide gel electrophoresis, whereas the liver enzyme was obtained exclusively as a 36-kDa protein. The purified 43-kDa ovary enzyme cleaved vitellogenin limitedly to produce yolk proteins at pH 5.6. The specific activity of ovary cathepsin D was five to six times lower than that of the liver enzyme, as measured by hemoglobin-hydrolysis at pH 3, but the ovary enzyme was shown to be superior to the liver enzyme in terms of vitellogenin-cleaving activity, as examined at pH 5.6. Ovarian enzyme preparations contained variable amounts of 36-kDa species; this form was considered to be an autolytic product of the 43-kDa form arising during purification, because it was not detected in oocyte extracts but was generated by incubation of the purified 43-kDa enzyme alone in an acid solution. The conversion of the 43-kDa form by hepatic factors was accompanied by a marked increase in hemoglobin-hydrolytic activity.     

Acid hydrolysis behaviour of microbial cellulose II

A mutant strain of Acetobacter xylinum produces cellulose of anomalous band-like form (‘native band’), and this material has been found to be cellulose II, presumably having a folded-chain structure (according to recent work by Kuga et al.). In addition to the previous results of electron diffraction, X-ray analysis showed that this band material was composed of virtually pure cellulose II. We have studied the acid hydrolysis behaviour of this material to obtain additional evidence for the proposed structure. When hydrolysed with 1 N hydrochloric acid at 100°C, the degree of polymerization (DP) of the material decreased rapidly from 322 ( ) to 18.3 ( ). The latter value (levelling-off DP) corresponds to the observed width (10 nm) of strand-like constituents of the band material. The sample dissolved in and regenerated from 8.75% aqueous sodium hydroxide lost its original characteristic morphology and became irregular-shaped agglomerates. The leveling-off DP of this regenerated sample was 55.2 ( ), a typical value for common regenerated celluloses. These findings as a whole strongly suggest that the cellulose molecules in the native band are selectively cleaved at sharply folded parts by acid, producing fragments of the length of folding periodicity.     

Difficulties in integrating the IT qualification test and training curriculum

There is a serious shortage of information technology (IT) engineers in Japan. Two closely related projects to solve the problem have been running at a goverment level: the Information Technology Engineers Examination (ITEE) and an educational material development activity nicknamed the CAROL project. ITEE is an official assessment test system of IT skills that has been run by the government since 1969. It attracts a large number of applicants and is recognized as an effective measure for hiring by Japanese management. CAROL consist of a curriculum and a set of computer-assisted instruction (CAI) courseware for entry-level IT engineers. The project has been active to achieve the CAROL curriculum, CAROL courseware development, and necessary revisions since 1986. The courseware propagation began in 1988. It initially focused on vocational schools, which had been the most significant suppliers of new IT hiring.With several years of experience in the two parallel projects, we have recognized that they are not achieving the expected objectives. The experience is the god discipline of ITEE and the traditional curriculum of CAROL do not match.The two systems for IT engineer development dearly need an integrated scheme. The inegration will not be easy because ITEE has a long history, with a large number of applications (some 500,000 in 1990). The CAROL project has to accept the requirements of Japanese vocational schools, which are the major portion of the expected customers. Moreover, they are not a part of official education and are not regulated by the government.The 20-year-old ITEE has to develop a new discipline that reflects the innovation of IT technology and the growth of the IT industry.A revision of the CAROL system is necessary so that it reflects the requirements of the real world and the new educational techniques.The objective of this paper is to discuss the problems of integrating the two projects so that they can work together toward the common objective with better efficiency.