Preparation and evaluation of Cu2ZnSnS4 thin films by sulfurization of E---B evaporated precursors

By sulfurization of E---B evaporated precursors, CZTS(Cu₂ZnSnS₄) films could be prepared successfully. This semiconductor does not consist of any rare-metal such as In. The X-ray diffraction pattern of CZTS thin films showed that these films had a stannite structure. This study estimated the optical band gap energy as 1.45 eV. The optical absorption coefficient was in the order of 10⁴cm⁻¹. The resistivity was in the the order of 10⁴ Ω cm and the conduction type was p-type. Fabricated solar cells, Al/ZnO/CdS/CZTS/Mo/Soda Lime Glass, showed an open-circuit voltage up to 400 mV.     

Flowsheet study of the thermochemical water-splitting iodine–sulfur process for effective hydrogen production

The Japan Atomic Energy Agency (JAEA) is performing research and development on the thermochemical water-splitting iodine–sulfur (IS) process for hydrogen production with the use of heat (temperatures close to 1000 °C) from a nuclear reactor process plant. Such temperatures can be supplied by a High Temperature Gas-cooled Reactor (HTGR) process. JAEA's activity covers the control of the process for continuous hydrogen production, processing procedures for hydrogen iodide (HI) decomposition, and a preliminary screening of corrosion resistant process materials. The present status of the R&D program is reported herein, with particular attention to flowsheet studies of the process using membranes for the HI processing.     

Phosphorylation of starch and dextrin by dry‐heating in the presence of phosphate,and their calcium phosphate‐solubilizing ability

Starch and dextrin were phosphorylated by dry‐heating in the presence of phosphate, and their properties were examined. The phosphorylation of starch was accelerated with decreasing moisture, rising incubation temperature and prolongation of the incubation period. However, a rise in incubation temperature, and lengthened incubation period caused increased browning and degradation. A decrease in the pH from 5.5 to 3.0 resulted in a modest increase of phosphorylation, but also marked browning and degradation. When potato starch was phosphorylated at 140°C and pH 5.5 for 24 h, its phosphorus content was increased up to 3.47%, with fewer side reactions. Phosphorlylated starch and dextrin had calcium phosphate‐solubilizing abitity. Phosphorylated dextrin with 2.42% phosphorus had about half the calcium phosphate‐solubilizing ability of casein phosphopeptide (CPP). The possibility of substituting of phosphorylated starch and dextrin for CPP as a calcium phosphate‐absorption enhancing material is discussed herein.     

Females of the Bumblebee Parasite, <Emphasis Type="Italic">Aphomia sociella</Emphasis>, Excite Males Using a Courtship Pheromone

Aphomia sociella (Lepidoptera: Pyralidae: Galleriinae) is a parasitic moth of bumblebees. Behavioral experiments show that A. sociella females emit semiochemicals that influence male pre-mating behavior and serve as a courtship pheromone. GC/EAD and two-dimensional GC/MS (GCxGC-TOFMS) analyses of extracts of females revealed three antennally active compounds. Comparative GC and GCxGC-TOFMS analyses of extracts and synthetic standards confirmed the identity of the antennally active compounds as hexan-1-ol (1), 6,10,14-trimethylpentadecan-2-one (2), and 6,10,14-trimethylpentadecan-2-ol (3). In laboratory bioassays, alcohol 3 and, at higher doses, ketone 2 initiated male courtship behavior associated with ultrasonic production. Hexan-1-ol (1) and ketone 2 enhanced the activity of alcohol 3. These data suggest that hexan-1-ol, 6,10,14-trimethylpentadecan-2-ol, and 6,10,14-trimethylpentadecan-2-one constitute the female-produced courtship pheromone of A. sociella.     

全库铺设沥青混凝土面板水库的抗震设计

介绍在建中日本最大规模的全库铺设沥青混凝土面板水库的抗震设计。基于水库所处的地形、地质及堤体填筑条件，酋先对水库整体进行三维有限元动力分析，从总体上掌握水库的地震反应特性；然后对变形较大的断面进行详细的二维动力分析，获得面板的最大动应变。同时，通过大量室内试验，确定满足施工要求的沥青混凝土配合比及其物理力学特性。根据面板的材料特性及其构造特点，提出二级抗震设防的极限状态设计法，并对该水库面板的抗震性能进行校核。     

Mechanical,setting, and biological properties of bone cements containing micron-sized titania particles

In this study, polymethylmethacrylate-based composite cements containing 40–55.6 wt% micron-sized titania (titanium oxide) particles were developed, and their mechanical, setting, and biological properties evaluated. Three types of composite cement containing 40, 50, and 55.6 wt% silanized titania were designated ST2-40c, ST2-50c, and ST2-56c, respectively. In animal experiments, ST2-50c and ST2-56c were implanted into rat tibiae and solidified in situ. An affinity index was used to evaluate osteoconductivity. Compressive and bending strength of ST2-56c was 147.7 ± 3.2 and 69.3 ± 7.4; those of the other cements exceeded 100 MPa and 50 MPa, respectively. The affinity indices of ST2-56c were 42.1 ± 12.9 at six weeks and 53.4 ± 16.6 at 12 weeks, and were significantly higher than for ST2-50c and a commercial PMMA bone cement within 12 weeks. Our data indicate that bone cement containing micron-sized titania particles can be applied to prosthesis fixation as well as vertebroplasty, and ST2-56c is a good candidate cement.     

Formation of a nanogroove-striped NiO surface using atomic steps

A nanogroove-striped pattern was formed on a NiO film surface. The periodic nanopattern was successfully obtained over the entire surface via high-temperature annealing of the epitaxial NiO thin film, which was grown on an atomically stepped sapphire substrate at low temperature. The depth, width and interval of straight nanogrooves were about 3?nm, 35?nm and about 100?nm, respectively. The periodicity of the stripe agrees well with that of the atomic steps of the substrate.     

Analytical investigation of thermal and mechanical load effects on stress distribution in adhesive layer of double-lap metal-composite bonded joints

Significant thermal stresses are induced in the adhesive layers of a metal-composite bonded joint owing to the large temperature change associated with the difference in the coefficients of thermal expansions of metals and composite adherends. In this study, a theoretical analysis of shear and peel stresses in adhesive layers of a double-lap metal-composite bonded joint is carried out to evaluate the effects of thermal and mechanical loads on the stress distribution in the adhesive layer. The effects of temperature change and adhesive thickness on the shear and peel stresses in the adhesive layer of the bonded joint, with and without external forces, are examined based on the theoretical analysis. The results calculated for the condition involving a mechanical load application to the bonded joint and a decrease in temperature indicate that the absolute value of the shear and peel stresses peak at both ends of the adhesive layer, and that the absolute value of the peak stresses increases in the case of a thinner adhesive layer. When mechanical and thermal loads are simultaneously applied to a double-lap joint, shear and peel stresses synergistically increase at one end of the adhesive layer and decrease with an offset at the other end.     

Function of second glucan binding site including tyrosines 54 and 101 in Thermus aquaticus amylomaltase

Amylomaltase from Thermus aquaticus catalyzes three types of transglycosylation reaction, as well as a weak hydrolytic reaction of alpha-1,4 glucan. From our previous study [Fujii et al., Appl. Environ. Microbiol., 71, 5823-5827 (2005)], tyrosine 54 (Y54) was identified as an amino acid controlling the reaction specificity of this enzyme. Since Y54 is not located around the active site but in the proposed second glucan binding site that is 14 A away from catalytic residues, the functions of Y54 and the second glucan binding site are of great interest. In this study, we introduced mutations into another tyrosine (Y101) in the second glucan binding site. The obtained mutated enzymes were subjected to all four types of enzyme assay and the effects of mutations on the reaction specificities of these enzymes were comprehensively investigated. These studies indicated that the amino acid substitution at Y54 or Y101 for removing their aromatic side chain increases cyclization activity (intra-molecular transglycosylation reaction) but decreases disproportionation, coupling and hydrolytic activities (inter-molecular reactions). The superimposition of the reported structures of the enzyme with and without substrate analog revealed the occurrence of a conformational change in which a donor binding site becomes open. From lines of evidence, we conclude that the binding of glucan substrate to the second glucan binding site through an interaction with the aromatic side chains of Y54 and Y101 is a trigger for the enzyme to take a completely active conformation for all four types of activity, but prevents the cyclization reaction to occur since the flexibility of the glucan is restricted by such binding.     

Multi‐Enzymatic Synthesis of Optically Pure β‐Hydroxy α‐Amino Acids

A novel enzymatic production system of optically pure β‐hydroxy α‐amino acids was developed. Two enzymes were used for the system: an N‐succinyl L ‐amino acid β‐hydroxylase (SadA) belonging to the iron(II)/α‐ketoglutarate‐dependent dioxygenase superfamily and an N‐succinyl L ‐amino acid desuccinylase (LasA). The genes encoding the two enzymes are part of a gene set responsible for the biosynthesis of peptidyl compounds found in the Burkholderia ambifaria AMMD genome. SadA stereoselectively hydroxylated several N‐succinyl aliphatic L ‐amino acids and produced N‐succinyl β‐hydroxy L ‐amino acids, such as N‐succinyl‐L ‐β‐hydroxyvaline, N‐succinyl‐L ‐threonine, (2S,3R)‐N‐succinyl‐L ‐β‐hydroxyisoleucine, and N‐succinyl‐L ‐threo‐β‐hydroxyleucine. LasA catalyzed the desuccinylation of various N‐succinyl‐L ‐amino acids. Surprisingly, LasA is the first amide bond‐forming enzyme belonging to the amidohydrolase superfamily, and has succinylation activity towards the amino group of L ‐leucine. By combining SadA and LasA in a preparative scale production using N‐succinyl‐L ‐leucine as substrate, 2.3 mmol of L ‐threo‐β‐hydroxyleucine were successfully produced with 93% conversion and over 99% of diastereomeric excess. Consequently, the new production system described in this study has advantages in optical purity and reaction efficiency for application in the mass production of several β‐hydroxy α‐amino acids.