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.     

Cavity and crater depth in hypervelocity impact

We discuss the depth of cavities and craters caused by hypervelocity impacts as a function of impact parameters such as impact velocity, projectile and target densities, and projectile diameter, in two extreme cases: the penetration of intact projectiles at low impact pressure and the hemispherical excavation at very high impact pressure. The relations between the depth and the impact parameters are obtained. Then, previous experimental results are compiled; crater depth normalized by projectile diameter and the ratio of projectile and target densities is plotted for glass, plastic, and metal projectiles and metal, rock, ice, foam, sheet-stack, and aerogel targets. The trends of the data are consistent with the relations in the extreme cases.     

Shaped silicon-crystal wafers obtained by plastic deformation and their application to silicon-crystal lenses.

Plastic deformation is an unlikely process by which to mould pristine silicon wafers into three-dimensional shapes owing to the inevitable detrimental impact that the resulting mechanically induced defects would have on their electrical properties. However, if one were to find a way of doing so without substantial degradation of these properties, a range of new applications might be opened up. Here we report on the successful plastic deformation of silicon crystal wafers for the preparation of wafers with various shapes. A silicon wafer was set between dies and pressed at high temperatures. One application of shaped wafers is as well-shaped concave silicon crystal lenses or mirrors. The lattice plane of such a crystal lens has a curvature exactly along the surface. A concave spheroidal X-ray lens, in the form of two-dimensional Johann and Johansson's monochromators, is proposed for an X-ray optical component system. We propose and demonstrate a new solar cell system with the concave silicon crystal mirror used as both a solar cell and a focused mirror. This system can make use of the reflected photons from solar cells.     

LaBGeO5 single crystals in glass and second-harmonic generation

Flower-shaped crystals with diameters of 100–200 μm consisting of LaBGeO₅ (LBGO) single crystals similar to petals were observed in the interior of transparent LBGO surface-crystallized glasses. Each flower-shaped crystal was radially grown from the surface of the included bubbles. A more intense second-harmonic generation was observed from the LBGO crystallized glasses with the flower-shaped LBGO single crystals compared to the samples without such crystals based on the Maker fringe technique and second-harmonic (SH) generation microscopy. The SH intensity for the flower-shaped LBGO single crystals monotonically decreased with increasing temperature up to 350 °C, less than the Curie temperature reported so far (530 °C). It is considered that the internal compressive stress induced by the difference in the thermal expansion between the LBGO single crystal and the corresponding glass affect the ferroelectric property of the flower-shaped LBGO single crystals in glass.     

螺杆压缩机性能模拟的误差分析及稳定性判据

在螺杆压缩机作动室的压力脉动模拟分析中,针对采用的数值计算方法———Rouge＿Kutta法可能由于计算舍入误差累积而造成计算发散,提出导入Simpson误差评价公式,建立了评价作动室排气过程中的计算误差的数学模型.同时针对排气行程中,由于作动室压力和排气室压力非常接近,造成计算误差增大的倾向,通过数学推证,得到对处于排气行程的作动室的压力脉动进行数值计算的稳定性判据,对模拟计算结果的收敛性提供保障.     

Czochralski growth of Yb doped oxyapatite for high power laser application

Ca₈(La,Yb)₂(PO₄)₆O₂ (Yb:CLPA) single crystals with the apatite-type structure could be grown from the melt using the Czochralski method. Grown crystal was 18 mm in diameter and 110 mm in length. It is transparent with slightly blue color. Neither visible inclusion nor crack was observed. Thermal conductivity of Yb:CLPA was calculated from the values of thermal diffusivity, heat capacity measurement and density. Luminescent characterization was carried out from the results of emission, absorption and Raman spectrum.     

Combinatorial pulsed laser deposition and thermoelectricity of (La1−xCax)VO3 composition-spread films

La_1−xCa_xVO₃ composition-spread film library was fabricated by combinatorial pulsed laser deposition and their thermoelectric properties were evaluated paralelly by the multi-channel probes of Seebeck coefficient and electric conductivity. Concurrent X-ray analysis verified the formation of solid soluted films in the full composition range (0x1) as judged from the linear variation of the lattice constants. The Seebeck coefficients of La_1−xCa_xVO₃ changed from a large negative value to almost zero with the increase of x, due presumably to the variation of valence in vanadium ions.The power factor in this library was as high as 0.6 μW/cm K², which was obtained at x=0, i.e. pure LaVO₃ grown at 800 °C.     

38. R&D on hydrogen production by high-temperature electrolysis of steam

One of the objectives of the high-temperature engineering test reactor (HTTR) is to demonstrate the effectiveness of high-temperature nuclear heat utilization, which aims to extend the application of nuclear heat to non-electric fields, especially to hydrogen production. As part of the development of the hydrogen production processes, laboratory-scale experiments of a high-temperature electrolysis of steam (HTES) had been carried out with a practical electrolysis tube with 12 solid-oxide cells connected in series. Using this electrolysis tube, hydrogen was produced at the maximum density of 44 N cm³/cm² h at a electrolysis temperature of 950 °C. Thereafter, to improve hydrogen production performance, a self-supporting planar electrolysis cell with a practical size (80 mm × 80 mm of electrolysis area) was fabricated. In the preliminary electrolysis experiment carried out at 850 °C, the planar cell produced hydrogen at the maximum density of 38 N cm³/cm² h, and the energy efficiency was almost as high as that obtained with the electrolysis tube at 950 °C. However, both electrolysis tubes and planar cells did not keep their integrity in one thermal cycle. Durability of the solid-oxide cell against the thermal cycle is one of the key issues of HTES.     

TRADE‐OFF BETWEEN APPROXIMATION ACCURACY AND COMPLEXITY FOR TS FUZZY MODELS

This paper proposes a transformation method that serves the trade‐off between the modelling complexity and accuracy of multi‐variable Takagi‐Sugeno fuzzy inference operator‐based modelling (TS fuzzy modelling). The relation between the number of fuzzy rules and the modelling accuracy is defined in the paper. The proposed transformation method is capable of finding the minimal number of fuzzy rules for a given accuracy of a given TS fuzzy model. A case study, focusing on a benchmark problem of fault diagnosis, developed in the framework of EC‐founded Research Training Network DAMADICS, of an actuator in a sugar factory, is presented to provide feasibility of the proposed method.