Short-Circuit Diffusion of Ba, Sr, and O during ATiO3 (A = Ba, Sr) Thin-Film Growth by the Hydrothermal–Electrochemical Method

The mass transport mechanism during the hydrothermal-electrochemical growth of polycrystalline thin films of ATiO₃ (A = Ba, Sr) perovskite onto Ti electrodes in A(OH)₂solutions has been studied by a tracer technique, using Ba and ¹⁸O atoms as respective tracers for A-site and oxygen atoms in SrTiO₃ host films. It was found that the ATiO₃film grows at the film/electrode interface by transport of both A-site and oxygen atoms from the solution to the interface. A-site and oxygen atoms are considered to diffuse as constituents of solution species, such as A²⁺, OH^-, and H₂O, through open short-circuit paths existing at grain boundaries.     

Effect of the Atomic Ratio of Ba to Ti on Optical Properties of Gold-Dispersed BaTiO3 Thin Films

Gold-dispersed BaTiO, thin films were prepared by the rf magnetron sputtering method. The atomic ratio of Ba to Ti in the films was varied and the effects on the linear and nonlinear optical properties were investigated. As the atomic ratio increased, the value of χ⁽³⁾/α₅₃₂ for the gold-dispersed BaTiO₃ thin films slightly increased. It was found that the increase in the value of χ⁽³⁾/α₅₃₂ is due mainly to a change in the crystalline state of the BaTiO₃ matrix. However, it was also found that the atomic ratio had a smaller effect on the value of χ⁽³⁾/α₅₃₂ than did the refractive index of the matrix.     

Permeability control of poly(methacrylic acid)–poly(ethylenimine) complex capsule membrane responding to external pH

Previously, permeability of partly crosslinked poly(acrylic acid)–poly(ethylenimine) complex capsule membranes has been shown to be controlled responding to external pH [K. Kono, F. Tabata, and T. Takagishi, J. Membr. Sci., 76 , 233 (1993)]. In order to improve pH-dependent permeation behavior of the polyelectrolyte complex capsule membranes, poly(methacrylic acid), which has hydrophobic side groups, was used as a polyanion component instead of poly(acrylic acid). The polyelectrolyte complex capsules composed of poly(methacrylic acid)–poly(ethylenimine) with a diameter of 5.2 mm were prepared. Permeation of phenylethylene glycol, which was used as a permeant, through the capsule membrane was quite limited at pH between 4 and 8. The permeation of the permeant across the capsule membrane in these pH regions was much less than that of poly(acrylic acid)–poly(ethylenimine) complex capsule membrane. However, the permeability constant was drastically increased in the order of 1 or 2 above pH 8 and below pH 4, depending on temperature. The Arrhenius plot for the permeation of phenylethylene glycol through the capsule membrane showed that the activation energy for the permeation is almost constant in the pH region between 4.5 and 8, but greatly decreases below pH 4 and above pH 8.8, suggesting occurrence of a significant change of the capsule membrane structure near these pH regions due to dissociation of polyelectrolyte complex. When environmental pH of the capsule was changed, release rate of phenylethylene glycol from the capsule was altered quickly and reversibly under acidic condition. © 1995 John Wiley & Sons, Inc.     

以柠檬酸铵为TiO2分散剂控制Si3N4-TiN复相陶瓷的显微结构

以Si3N4,AlN和TiO2为原料,Y2O3和Al2O3为烧结助剂,通过添加柠檬酸铵作为TiO2的分散剂,采用原位反应合成法制备TiN体积分数为5%的Si3N4-TiN复相陶瓷,在高温烧结过程中原料中的TiO2和AlN反应生成TiN.通过扫描电子显微镜观察了柠檬酸铵分散剂用量对Si3N4-TiN复相陶瓷显微结构的影响.结果表明:添加柠檬酸铵分散剂降低原料混合粉体中TiO2的团聚,获得组分均匀的Si3N4-TiO2-AlN复合粉体,从而提高Si3N4-TiN复相陶瓷中TiN相在Si3N4基体中的分散性,烧结后获得显微结构均匀的Si3N4-TiN复相陶瓷.当在体系中添加0.20g柠檬酸铵分散剂可以显著改善Si3N4-TiN复相陶瓷的显微结构,TiN晶粒被控制在0.2～0.3μm.     

Hydrothermal Synthesis of Interstratified Lizardite/Saponite

A novel interstratified lizardite/saponite which has never been found in nature is hydrothermally synthesized from uniform Si-Al-Mg gels at 300°C. The stacking ratios of lizardite layer to saponite layer in the structure are designed between 3/1 and 1/3. These materials give partially ordered X-ray diffraction patterns depending on the layer composition. The lattice-fringe image of the L/S = 1/1 sample shows that platelet particles have a thickness of 17.5 Å consisting of a lizardite layer (7.5 Å) and a dehydrated saponite layer (10.0 Å). They can disperse in water like smectite.     

Dynamic viscoelastic properties and thermal properties of Ni powder–epoxy resin composites

The composite materials containing metal Ni powder of 5–15 μm in size were prepared by use of the matrix epoxy resin of glycidyl amine crosslinked with bis-4-amino-3-methylcyclohexyl methane and 2,4-diamine 3,5-dimethyltoluene. Dynamic viscoelastic properties of the composites at various volume fraction (Φ_p) of Ni powder have been measured over the temperature range from 30 to 300°C. The peak temperatures in dynamic loss modulus–temperature diagrams of the composite increased with increasing Φ_p, although the peak position was abruptly shifted to lower temperatures in the range of Φ_p more than 0.245. At this high concentration of Φ_p, agglomeration of the particles occurring in the composite lead to reduction of the interaction between Ni particle and epoxy resin. Parallel studies on the thermal conductivity (λ) of the composites materials showed that the value of λ at Φ_p = 0.245 increased by approximately 7 times that of the original epoxy resin. The shape of Ni particles also affected the thermal durabilities of the composites; the rough surface of Ni powder yields a higher storage modulus of the composite than that of the materials containing the powder with a smooth surface, which had been brought through a ball-milling process. The finding suggested that the increasing in specific surface area of the powder improved the thermal durability of the composites as well as their mechanical properties. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2593–2598, 1998     

实用的蠕变与滞后误差的补偿方法

传感器的称重信号是由粘贴在用弹性材料做成的弹性体上的应变计给出的,由于温度、湿度以及弹性材料特性、结构等等许多变化会产生误差信号。在各种误差中,滞后和蠕变是典型的、由于材料和结构的弹性特性引起的。如不锈钢因有很好的耐候性而常常被作为弹性体材料,但其蠕变和滞后较大。相比之下应用更广泛的弹性材料是铝合金。     

Development of a low-energy and high-current pulsed neutral beam injector with a washer-gun plasma source for high-beta plasma experiments

We have developed a novel and economical neutral-beam injection system by employing a washer-gun plasma source. It provides a low-cost and maintenance-free ion beam, thus eliminating the need for the filaments and water-cooling systems employed conventionally. In our primary experiments, the washer gun produced a source plasma with an electron temperature of approximately 5 eV and an electron density of 5 × 10(17) m(-3), i.e., conditions suitable for ion-beam extraction. The dependence of the extracted beam current on the acceleration voltage is consistent with space-charge current limitation, because the observed current density is almost proportional to the 3∕2 power of the acceleration voltage below approximately 8 kV. By optimizing plasma formation, we successfully achieved beam extraction of up to 40 A at 15 kV and a pulse length in excess of 0.25 ms. Its low-voltage and high-current pulsed-beam properties enable us to apply this high-power neutral beam injection into a high-beta compact torus plasma characterized by a low magnetic field.     

Reactive dye dyeability of cellulose fibers with cellulase treatment

Peel strength and lap shear strength between aluminum and polyimide were measured at different imidization temperatures. Polyimide was synthesized from 3,3′,4,4′-benzophe-nonetetracarboxylic dianhydride (BTDA) and 4,4′-diaminophenylether (ODA). The interfacial adhesion between polyimide and aluminum shows a maximum value at the imidization temperature of 320°C. To relate the intefacial adhesion strength with chemical interaction between polyimide and aluminum the Fourie, transform infrared spectroscopy (FTIR) ATR technique was used. In addition, morphological studies on the peeled surfaces were also carried out. © 1996 John Wiley & Sons, Inc.