Characterization of Hydroxyapatite Film on Titanium Substrate by Sputtering Technique

Radiofrequeut magnetron sputtering technique was used to produce calcium phosphate coated on the titurdum substrates, and the sputtered coating films were crystallized in an autoclave at 110℃ using a low temperature hydrothermal technique. The crystallization of as-sputtered coating film on the titanium substrates were amorphous calcium phosphate film. However, after the hydrothermal technique, calcium phosphate crystals grew and these were cohumnar crystal. The Ca/P ratio of sputtered coating films in 1.6 to 2.0.     

DYNAMIC PROGRAMMING APPROACH TO THE DESIGN OF A SOLVENT EXTRACTION PROCESS IN FAST BREEDER REACTOR FUEL REPROCESSING

Solvent extraction process in nuclear fuel reprocessing is considerably large and complicated system. For the design of individual contactors, several computer codes for calculating concentration profiles have been developed. Based on these computer codes. Complex method and the concept of Dynamic Programming are applied to the solvent extraction process design problem, which is thereby reduced to a problem of optimization. Numerical calculations are carried out, resulting in optimal process variables well within the range of practicability.     

Characterization of Hydroxyapatite Film on Titanium Substrate by Sputtering Technique

1Introduction Calciumphosphatebioceramics,especially hydroxyapatiteCa10(PO4)6(OH)2isknowntobeoneof themostbiocompatiblematerialswithhumanbonesand teeth.Hydroxyapatite(HA)hasfavourablepropertiesas abiologicalimplantmaterial,owingtoitsexcellentbio compatibi…     

Application of X‐ray microcomputed tomography in the characterization of irradiated nuclear fuel and material specimens

X‐ray microcomputed tomography (μCT) was applied in characterizing the internal structures of a number of irradiated materials, including carbon‐carbon fibre composites, nuclear‐grade graphite and tristructural isotropic‐coated fuel particles. Local cracks in carbon‐carbon fibre composites associated with their synthesis process were observed with μCT without any destructive sample preparation. Pore analysis of graphite samples was performed quantitatively, and qualitative analysis of pore distribution was accomplished. It was also shown that high‐resolution μCT can be used to probe internal layer defects of tristructural isotropic‐coated fuel particles to elucidate the resulting high release of radioisotopes. Layer defects of sizes ranging from 1 to 5 μm and up could be isolated by tomography. As an added advantage, μCT could also be used to identify regions with high densities of radioisotopes to determine the proper plane and orientation of particle mounting for further analytical characterization, such as materialographic sectioning followed by optical and electron microscopy. In fully ceramic matrix fuel forms, despite the highly absorbing matrix, characterization of tristructural isotropic‐coated particles embedded in a silicon carbide matrix was accomplished using μCT and related advanced image analysis techniques.     

CATHEPSIN D AND ITS EFFECTS ON MYOFIBRILLAR PROTEINS: A REVIEW1

The molecular and enzymatic properties of the extensively studied enzyme cathepsin D are reviewed and additional information concerning its activity presented. Cathepsin D at pH 5.5 (37°C) degraded several myofibrillar proteins. The most rapidly hydrolyzed included titin and perhaps nebulin, myosin heavy chain, and M and C-proteins. The effects of cathepsin D on myofibrillar structure under these conditions included reduction in A band width, cleared central region in the A band, and dislocation of the Z line. Temperature was found to exert a strong influence on activity of cathepsin D and maximum activity was observed at 45°C with both muscle and hemoglobin substrates. Activity was evident at even higher temperatures and approximately 49% remained at 55°C (hemoglobin assay). Low temperature (i.e., < 15°C) however, has been observed to result in almost complete inactivity of the enzyme. The implications of this information for involvement of cathepsin D in postmortem proteolysis and tenderization were discussed.     

二甲醚氧化反应及其添加剂效应

采用加速量热仪（ARC）测定了二甲醚（DME）氧化反应温度变化和活化能（Ea）,考察了添加剂对DME热稳定性效应,分析热分解产物,探讨氧化反应机理. 结果表明,DME热氧化反应初始温度（To）为120 ℃,反应活化能Ea=167.3 kJ&#8226;mol-1.氧的存在是导致DME热稳定性下降重要因素,在氧化反应体系中添加Fe、Fe2O3、Al等时, To和Ea值减小,它们有促进氧化反应作用,特别是有过氧化物存在下,由于自由基的引发,显著降低DME热反应初始温度和反应活化能,抗氧剂能提高热稳定性.     

LITHIUM-ION SIEVE PROPERTY OF λ;-TYPE MANGANESE OXIDE

The adsorptive properties of A-Mn0₂for mono and divalent metal ions were investigated by pH titration and by measurements of the distribution coefficients(Kd's) of the metal ions. The pH titration curve showed an apparently monobasic acid type for a H⁺-Li⁺exchange. Those for H⁺-K⁺and H⁺-Cs⁺exchanges were nearly the same as that for blank titration. The lithium ion uptake increased with increasing solution pH and reached 5 meq/g at pH 11. X-ray diffraction analyses showed that the adsorption of lithium ions caused an increase in the lattice constant of a cubic unit cell. The potassium and cesium ion uptakes were nearly zero over a pH range between 4 and 11. A-Mn0₂showed a remarkably high Kd value for lithium ions, compared to a cation exchange resin. The selectivity sequences were Na⁺< K⁺< Rb⁺< Cs⁺<< Li⁺for alkali metal ions, Mg²⁺< Ca²⁺< Sr²⁺< Ba²⁺for alkaline earth metal ions, and Ni²⁺< Zn²⁺< Co²⁺< Cu²⁺for transition metal ions.     

Effect of Cathepsin D on Bovine Myofibrils under Different Conditions of pH and Temperature

Purified cathepsin D was incubated with bovine skeletal muscle myofibrils under in virro conditions resembling those found in postmortem muscle. SDS-PAGE analysis of myofibrils treated at pH 5.5 and 37°C and the sedimented, showed degradation of myosin heavy chains and titin. A small amount of actin, tropomyosin, troponins T and I, and myosin light chains also were degraded. The cathepsin D treated myofibrils were not fragmented to any greater extend than untreated myofibrils. Raising the pH and/or lowering the temperature greatly reduced the effectiveness of cathepsin D suggesting that the enzyme does not play a principal role in the tenderization process occurring in muscle postmortem.     

Converter Using SiC‐MOSFET for Ultra‐High‐Speed Elevator

In this study, we developed a converter based on SiC (Silicon Carbide)‐MOSFET for use in ultra‐high‐speed elevators, with a reduced volume of 15% compared with the conventional converter. We succeeded in reducing the power loss of the converter unit by 56% compared to the conventional converter in one round trip under high temperature condition. Recently, because of their useful characteristics, wide‐gap semiconductors, such as SiC and GaN, have gained considerable attention for use in various applications in the power electronics systems. Therefore, we studied the use of a converter in elevator systems based on SiC‐MOSFET. We used a 1200 V/800 A SiC‐MOSFET module for the converter unit. We developed a prototype of the converter unit and the control panel by applying for the SiC‐MOSFET module for an ultra‐high‐speed elevator. As a result, the setting area of the control panel (main part) becomes less than 43% of the conventional panel. We tried to demonstrate the working of a 68‐kW elevator by applying the prototype control panel. Because of the characteristic of the switching loss of SiC‐MOSFET, the power loss of the converter unit has almost no dependence on temperature. An energy‐saving effect of approximately 17% was achieved in the total elevator system in one round trip under high‐temperature condition.