Effect of platinum on the critical current density of fluorine-doped YBa2Cu3Ox superconductors

The critical current density, Jc, in fluorine-doped YBa2Cu3Ox bulk superconductors has been measured at several temperatures. The measured Jc value is 108 A m-2 at 77 K and 0.5 T. A sample with a larger critical current density can be produced by the addition of a small amount of platinum during the sintering process. The added platinum has the effect of evenly distributing Y2BaCuO5 particles and voids in the matrix in comparison with the undoped sample. These distributions of Y2BaCuO5 particles and voids are reflected in an increase in the critical current density. However, these distributions are not directly related to the observed peak effect in the critical current density. If the fluorine-doped YBa2Cu3Ox superconductor consists of the matrix and a phase with a Ginzburg–Landau parameter, that is slightly different from that of the matrix, then the occurrence of the peak effect can be explained.     

采用神经网络控制的超精密平面定位

设计了一种基于激光莫尔信号的超精密平面定位装置,该装置可实现高精度位置检测及X-Y-θ 三自由度的全自动精密平面定位。激光莫尔信号传感器为相位相差 180°的两组衍射光栅,构成差动光栅技术,可有效提高位置检测信号灵敏度及定位精度。针对系统存在非线性,精确控制模型难以建立的缺陷,提出基于 RBF 神经网络的精密定位控制,其控制响应快、稳定性好、鲁棒性强,可有效改善控制质量,提高定位速度。实验结果表明,基于激光莫尔信号的精密定位装置可获得亚微米级的平面定位精度。     

Flexible Amorphous Si Solar Cells

Seasonal and temporal unbalanced demands of electric power are increasing year after year. While an even demand from the load must be maintained in order for the development of a typical solar power generation system for an ordinary usage in the near future, the most important aspect is to develop a low-cost system.

In this paper, the load pattern for a factory is chosen as the subject of the research, which has a lot of advantageous factors such as day-load and stability of the day to day load pattern. The two solar power generation systems which are shown below are investigated: one is connected with commercial power source and the other has equipment for charging the battery using low-cost night electric power. Both systems are simulated using meteorological data and are investigated not only from the energy flow in the systems but also from an economic viewpoint based on current constructive cost. In addition, the influence of the arrangement of holiday load patterns on the effective energy generated by photovoltaic panels are also researched.     

Valency Control of Glow Discharge Produced a-SiC:H and its Application to Heterojunction Solar Cells

A new type of amorphous silicon solar cell having a conversion efficiency of 8% level is introduced. The cell has a wide band gap window layer made of hydrogenated amorphous silicon carbide, (a-SiC:H), with a good valency control. Electrical, optical and optoelectronic properties of a-SiC:H have been investigated, together with their valency controllability. A design concept and some key technologies to improve solar cell performance with this new material are demonstrated. A series of technical data on material preparation and cell performance are presented. Clear improvements in cell performance, not only I_DC but also V_DC, have been obtained. The realistic limit of the conversion efficiency in a-Si solar cells is estimated and discussed.     

Comparison Study of (001)-/(100)-Oriented Epitaxial and Fiber-Textured Pb(Zr,Ti)O3 Thick Films Prepared by MOCVD

(001)-/(100)-oriented epitaxial PZT films and fiber-textured PZT films with a thickness of 2 μ m were deposited on (100) _c SrRuO₃//(100)SrTiO₃ and (111)Pt/TiO₂/SiO₂/(100)Si substrates, respectively, by metalorganic chemical vapor deposition (MOCVD). Crystal structure and the electrical properties were compared for epitaxial PZT films with those of fiber-textured ones, which had the same out-of-plane orientation but different in-plane orientation. The constituent phase change from the single phase of tetragonal PZT, mixture phases of tetragonal and rhombohedral ones and the single phase of rhombohedral one for both films when the Zr/(Zr + Ti) ratio increased. The out-of-plane lattice parameter of (001)- and (100)-axes of PZT films were almost the same value for both films. This indicates the residual strain in the PZT films was almost the same. Dielectric constant (? _r) took the maximum value around the MPB composition for (001)-/(100)-oriented fiber-textured films but was almost independent of the Zr/(Zr + Ti) ratio for epitaxial ones. Moreover, there was no significantly dependence of remanent polarization (P _r) value on the Zr/(Zr + Ti) ratio for (001)-/(100)-oriented fiber-textured films, while it took minimum value near the morphotropic phase boundary (MPB) for epitaxial ones.     

Curdlan: Properties and Application to Foods

Gel formation of curdlan at 100–130°C and behaviors of curdlan gels under frozen state were investigated by measuring gel strength and syneresis. Even when aqueous suspensions of curdlan were heated to 100°C or higher, they formed a gel, and gel strength increased with temperature. Curdlan gel was also stable against freezing and thawing. The syneresis of a 4% curdlan gel after freezing and thawing was reduced from 20.6% to about 2.1% by addition of 5% waxy corn starch and to 8.9% by addition of 20% sucrose. Suggested by these findings, new applications to foods have been developed, especially those subject to retorting and/or freezing.