Ti-Co氧化物中间相的形成与组织结构

采用深胶凝胶工艺技术,以ＣｏＣ１２、Ｔｉ（Ｃ４Ｈ６Ｏ）为原料,经混合、水解、缩聚、固化、氧化制备中间相ＣｏＴｉＯ３的超细粉末,并用扫描差热分析（ＤＴＡ）、Ｘ－射线衍射分析（ＸＲＤ）及航向电子分析（ＴＥＭ）等手段分析了ＣｏＴｉＯ３的形成、原子间键合、晶体结构与组织形貌。     

Al-Ti-B-RE细化剂对Al-7．0Si-0．55Mg合金显微组织和力学性能的影响

研究添加Al-5Ti-lB-RE细化剂对Al-7．0Si-0．55Mg（A357）合金的显微组织和力学性能的影响。先利用真空熔炼技术制各Al-7．0Si-0．55Mg合金,然后在Al-7．0Si-0．55Mg合金中加入不同成分的Al-5Ti-1B-RE中间合金。通过X射线衍射仪（XRD）、金相显微镜（OM）和扫描电子显微镜（SEM）对显微组织和拉伸试样的断口形貌进行观察。在室温下对合金的力学性能进行测试。观察Al-5Ti-1B-RE细化剂的形态以及内部结构,可以发现以TiB,为异质形核核心的TiAl3／Ti2Al20RE的壳层结构相。在Al-7．0Si-0．55Mg合金中加入Al-5Ti-1B-3．0RE细化剂后,抗拉强度会有明显提升,直到0．2％添加量时,抗拉强度会达到峰值。     

圆弧“U”形结构安装座铸造工艺改进

安装座为精铸件,其结构总体呈半圆弧形,一端为“U”形结构,该产品主要工艺难点为圆弧径向及“U”形结构开口端易变形,圆弧径向两端加工后易出现“黑皮”。通过工艺改进运用反变形工艺、工艺拉筋等工艺措施有效解决铸件变形问题,提高产品铸造工艺出品率。     

Active Polymer Gel Actuators

Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a worm-like motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.     

Tribological Mechanisms of Steels with Respect to Diamond-Like Carbon in Terms of Energy Input

The wear behavior of a carbon steel (SUJ2, ASTM E52100 or similar) and a stainless steel (SUS440C, ASTM 440C or similar) with respect to diamond-like carbon (DLC) was evaluated based on the energy input. The conventional wear equation (Holm-Archard equation) was derived based on the friction force. The wear–energy equation was transformed from the Holm-Archard equation. The measurement method of the energy input induced by a tribometer is proposed, and the equation describing the relationship between the friction coefficient and energy input is introduced. The tribology functions derived from the energy equations are proposed. The wear behavior of the steel balls against the DLC is discussed in terms of tribology functions.     

Drying characteristics of porous material immersed in a bed of hygroscopic porous particles fluidized under reduced pressure

A relatively large wet material was immersed in a fluidized bed of hygroscopic porous particle (silica gel beads) under reduced pressure. And then the drying characteristics were compared with those in the case of inert particle (glass beads). The comparison of drying characteristics is performed experimentally and theoretically. In calculation, the water transfer from the sample to the fluidized bed was considered. The calculation results are in good agreement with the experimental data. The effects of the operational conditions (the pressure in the drying chamber and the temperature of the drying gas) on the drying characteristics were also examined in both fluidizing particles.The drying finishes earlier in the case of hygroscopic porous particle than in the case of inert particle regardless of pressure in the drying chamber, since the water transfer from the sample facilitates the drying in the case of hygroscopic porous particles. The temperature decrement in drying appears in the case of inert particle. This phenomenon is also observed in the case of hygroscopic porous particle, but the decrement degree of the temperature is much smaller than that in the case of inert particle. The difference of the minimum temperature in the sample in drying between the cases of hygroscopic porous particle and inert particle is very slight for different pressures in the drying chamber.     

Development of poly(vinyl alcohol) hydrogel for waste water cleaning. II. Treatment of N,N-dimethylformamide in waste water with poly(vinyl alcohol) gel with immobilized microorganisms

The activated sludge that had been sufficiently cultivated with DMF-containing waste water was entrapped and immobilized in spherical poly(vinyl alcohol) (PVA) hydrogel particles. Features of numbers and distribution of bacteria in the resultant PVA gel were estimated. The DMF-decomposing bacteria named Bacillus cereus D-1 was isolated. Several morphological and physiological responses of the bacteria were revealed. Spherical PVA gel with the DMF-decomposing bacteria prepared through of freezing and thawing was tested for treatment of DMF-containing effluent. Test results have shown the ability of stable operation and maintenance at the same capacity of 1 kg/m³/day by both a basic study and a bench plant test. © 1995 John Wiley & Sons, Inc.     

Mechanical properties of porous titanium compacts prepared by powder sintering

Porous Ti compacts for biomedical applications are successfully fabricated in the porosity range from 5.0 to 37.1 vol% by controlling sintering conditions and Ti powder sizes. Young’s modulus and bending strength at the porosity of around 30 vol% are found to be similar to those of human cortical bone.     

MD STUDY ON INTERFACELIKE PHENOMENA IN SUPERCRITICAL FLUID

An interfacelike structure obser ved during heat transfer in fluid near the critical point has been analyzed using a molecular dynamics (MD) method for a simple fluid modeled by the Lennard-Jones (12-6) potential. Under the condition that a temperature gradient exists, MD simulations at supercritical pressure reproduced a structure which is similar to the normal liquid - vapor interface obser ved at subcritical pressure. Some characteristics of the interfacelike structure, such as density profile, interface thickness, and interfacial tension, are compared with those of a subcritical liquid - vapor interface. The predicted value of the supercritical interfacial tension is compared with the value that was estimated using a theory of hydrodynamic instability due to the interfacial tension.