Formation Reaction of ZrO2 Scatterers in ZrF4-Based Fluoride Fibers

This paper clarifies the formation reaction of ZrO₂ crystals which appear as extrinsic scatterers in fluoride fibers. EPMA analysis indicates that BaO exists at grain boundaries of BaF₂ purified by sublimation. BaO reacts with ZrF₄ to form ZrO₂ at 600°C during a glass-melting process. The ZrO₂ formation reaction is influenced by H₂O. Ba(OH)₂, which is formed by the reaction between BaO and water vapor, melts at 370° to 420°C and reacts with ZrF₄ to form ZrO₂ at 450° to 520°C. When low-oxide-content BaF₂ is used for fiber preparation, scatterers significantly decrease.     

Contribution of Paramyosin to Marine Meat Gel Characteristics

The properties of the paramyosin-natural actomyosin system gels were considerably improved by paramyosin, and a strong and firm gel was formed. This effect of paramyosin on gel properties was large at relatively low paramyosin contents. Paramyosin considerably altered the characteristic texture of the marine meat gel products made from invertebrate meats. Two-step heating, including the low temperature setting, was effective in increasing the gel strength for the paramyosinnatural actomyosin system gels. The strengthening effect of setting on the gel strength became larger on increasing the paramyosin content.     

Controlled Crystallization of Amorphous Si3N4by Ti and CI Additives

Thin films of amorphous Si₃N₄ were prepared by the rf-sputtering method, and the effects of titanium and chlorine additives on its crystallization were examined. When Ti-doped amorphous Si₃N₄ was heated, TiN precipitated at >1100°C; the TiN precipitates promoted the conversion of amorphous Si₃N₄ to β-Si₃N₄. Chlorine led to preferential conversion of amorphous Si₃N₄ to α-Si₃N₄.     

Development of High‐Power Density Interleaved dc/dc Converter with SiC Devices

We developed an interleaved dc/dc converter with SiC devices. We applied full‐SiC modules including MOSFETs and SBDs to the interleaved dc/dc converter to achieve a high‐power density. An SiC has a high temperature resistance, which facilitates an improvement in high‐frequency drives. We achieved a high‐power density by utilizing this high temperature resistance. We also fabricated a prototype and tested it with loads up to 65 kW.     

Influence of sputtering power on properties of ZnO thin films fabricated by RF sputtering in room temperature

High mobility and c-axis orientated ZnO thin films were deposited on glass substrates using RF sputtering method at room temperature.Structural properties of ZnO thin films were investigated by X-ray diffraction (XRD).Surface morphology and roughness were studied with scanning electron microscopy (SEM) and atomic force microscopy (AFM).Electrical properties were measured at room temperature using a Hall effect measurement system.The influence of sputtering power on characteristics of ZnO thin films is studied.The results indicate that the sputtering powers have great influence on the crystal quality and mobility of ZnO thin films.By using optimized sputtering conditions,high crystal quality ZnO thin films with Hall mobility of 34 cm 2 /V·s at room temperature were obtained.     

NUMERICAL ANALYSIS OF THE INFLUENCE OF THE TIP CLEARANCE FLOWS ON THE UNSTEADY CAVITATING FLOWS IN A THREE- D IMENSIONAL INDUCER

To clarify the influences of the tip clearance flows on the unsteady cavitating flow,the three-dimensional unsteady cavitating flows through both the two-dimensional cascades and the three-dimensional inducer with and without tip clearance are performed numerically.The governing equations for the compressible fluid flow with the DES turbulence model are employed with the assumption of the isentropic process of liquid phase.The evolution of cavities is represented as the source/sink of vapor phase.The basic equations in the curve linear coordinate are solved by the finite difference method.As the results of the three-dimensional cavitating flows through the two-dimensional cascades,the tip clearance flows from the pressure side to the suction side of the blade produces the tip vortex cavitation,which affects the sheet cavitation on the leading edge of the next blade and enhances the blockage effect near the casing than the flows without tip clearance.On the other hand,in the case of the three-dimensional inducer,the large backflow cavitation is observed around the inlet of the inducer,where the cavities are developed on the casing by the tip clearance flows.The large pressure gradient between the non-cavitating pressure side and the cavitating suction side enhances the tip clearance flows.The calculation considering the tip clearance reproduces the developed cavitation region similar to that of experimental visualizations.Additionally,the backflow cavitation rotates with the speed slower than the rotation speed of the inducer.Then,the rotation of backflow cavitation causes the periodic fluctuation of the outlet pressure greater than that of the inlet pressure.     

双模式非稳定结构移动机器人

双轮不稳定结构移动机器人具有两轮分别驱动、同轴且左右平行布置的机构特点,通过对机器人运动姿态的实时控制可实现其运动平衡的稳定和在狭小空间内的零半径转弯.围绕该机器人所涉及的机械结构、动力学模型及平衡控制方法加以研究,解释机器人在载重的情况下,在不同坡度、不同粗糙状态的路面和狭小空间内的运动学及动力学特性,并基于运动平衡模型来实时控制机器人的姿态.机器人样机质量轻、结构紧凑、体积小、功耗低,可以由单人携带.它有载人和载物的双模式控制系统,其中载人模式主控制器通过分析传感器数据调整控制参数,载物模式主控制器接收控制终端命令来完成任务.通过建立机器人动力学模型和状态空间控制模型,并对模型进行仿真,得到了机器人的反馈控制参数,最后通过爬坡、原点旋转、通过障碍物、载人前进后退等试验验证了设计方法的有效性.     

采用MCECR等离子体溅射方法制备硬碳膜

采用封闭式电子回旋共振(MCECR)等离子体溅射的方法在硅(100)基片上沉积了高质量的硬碳纳米微晶薄膜,膜层厚度约40 nm,采用氩等离子体溅射碳靶.薄膜的键结构采用X射线光电子能谱仪(XPS)分析,纳米结构采用高分辨率透射电子显微镜(HRTEM)分析.本文研究了基片偏压对薄膜的纳米结构、摩擦特性(摩擦系数及磨损率)以及薄膜的纳米硬度的影响.摩擦特性采用POD摩擦磨损仪测试,纳米硬度采用纳米压入仪测试.     

Dynamic Viscoelastic Behavior of F-actin on Heating

Although a relatively large amount of actin is contained in myofibril, the role of F-actin in the thermal gelation of muscle proteins has been little studied. We investigated the dynamic viscoelastic behavior of F-actin on heating to clarify the role of F-actin in the thermal gelation. F-actin did not form an elastic gel on heating but did turn into a curdy matter. In addition, F-actin showed no development either of the storage modulus or the loss modulus during a rise in temperature. These results suggest that F-actin negatively affects the gel formation of fish muscle proteins.     

Role of Muscle Fibers in Contributing Firmness of Cooked Fish

Cooked muscle tissue of five fish species were observed by optical and scanning electron micrography. Species with firm texture had thin muscle fibers with considerable heat-coagulating material between them; species having soft texture had thick muscle fibers with little heat-coagulating material. When the cooked muscles were compressed by a Texturometer, muscle fibers of the species having firm texture slid or shifted over one another to a lesser extent than those of species with soft texture. The heat-coagulating material seemed to obstruct the displacement of the fibers. The diameter and mobility of muscle fibers are determinative of firmness of fish muscle tissue.