Mechanism of Ni-Zn Ferrite Formation in the Presence of Molten Li2SO4-Na2SO4

Nickel-zinc ferrite powder was prepared from the constituent oxides in the presence of molten Li₂SO₄-Na₂SO₄. The effect of ZnO on the reactivity of NiO was studied. The process of Ni-Zn ferrite formation was followed by X-ray diffraction and thermomagnetic analyses. Particle size and shape of the product were determined by scanning electron microscopy. In the presence of molten salt, ZnO enhances the reactivity of NiO, and Ni-Zn-ferrite formation is completed at lower temperature than Ni ferrite formation. In the reaction for the formation of Ni-Zn ferrite, Zn ferrite forms before NiO is incorporated into the ferrite phase. The reaction between the initially formed Zn ferrite and NiO leads to a rate of Ni-Zn ferrite formation higher than that of Ni ferrite formation from NiO and Fe₂O₃.     

DEFORMATION BEHAVIOR OF γ-TiAl SINGLE CRYSTALS AT DIFFERENT TEMPERATURES

在－１９６－１１００℃温度范围内,利用压缩试验研究了γ－ＴｉＡｌ单晶（Ａｌ的原子分数为５６％）在「００１」,「１５２」,「０２１」,「２３３」,「１９１」,「２５１」,「１１０」七个晶体取向上的塑性变形行为,它们的屈服强度温度关系曲线都可分成三个部分：－１９６－６００℃屈服强度随温度的升高先是快速下降,达到室温附近以后基本保持不变;６００℃以上,屈服强度随温度的升高而反常升高,随晶体取向的不同在７     

The Synergistic Taste Effect of Monosodium Glutamate and Disodium 5'-Inosinate

SUMMARY— The synergistic phenomenon between the taste of monosodium glutamate (MSG) and disodium 5'-inosinate (IMP) [7.5 H₂O] was studied and the relationship expressed as a mathematical model. The phenomenon could be measured quantitatively by fitting the proposed model to the results of the experiment.
The concentration of MSG equivalent to the taste intensity of that given by the mixture of MSG and the ribonucleotide is represented by the following equation:
y = u +γuv
where y is the equivalent taste intensity of the mixture in terms of g/dl of MSG, u is equal to g/dl of MSG in the given mixture, v is equal to g/dl of sodium 5'-inosinate in the given mixture, and γ is a constant.
The γ value for IMP was calculated from extensive sensory testing as 1.218 × 10⁸.     

Al2O3纤维砂轮的开发及其磨削特性

细磨粒砂轮用于高精度磨削。然而,由于细磨粒具有较小的结合面积和强度,即使在正常的磨削条件下,磨粒易于从砂轮表面上脱落,导致加工精度与效率低下。近年来,由于Al2O3纤维具有优良的机械与物理化学性能如高强度、高弹性模量、耐磨损、耐高温氧化及耐酸、耐碱等,与基质材料具有良好的相容性,因而被广泛地用于FRP、FRC和FRM等的强化材料。A2O33纤维的平均直径和长度分别为3—5μm和数百μm,比相同直径的细磨粒具有较大的结合面积和强度。因此,1998年以来,日本山口胜美、洞口严教授和中国魏源迁教授使用Al2O3纤维替代磨粒作为磨料,与酚醛树脂结合剂结合,成功地开发了一种A12O3纤维砂轮,能克服磨粒砂轮的缺陷。该砂轮中的纤维排列方向与磨削面相垂直,纤维的端部可用作为切削刃,而且纤维砂轮比磨粒砂轮细密,使用纤维砂轮可实现干磨削和纳米加工。为了考察Al2O3纤维砂轮的磨削特性,本文对难加工材料如模具钢SKD11(HRC60)进行了大量的磨削试验,试验结果表明能获得纳米级加工表面(Ra2．1nm／Ry22nm)。     

Development of Magnetic Levitation System for Science and Technology Education: Magnetic Levitation Control by Using a Hall Element Displacement Sensor with Neural Network

In this study, we developed a magnetic levitation system using a Hall element displacement sensor with neural network for science and technology education. The sensor configured with three Hall elements was devised in order to measure displacement from an electromagnet to a levitated object with a permanent magnet. Use of the Hall element displacement sensor achieves a lower cost magnetic levitation system. Furthermore, three‐layered feedforward neural network was utilized in order to improve the precision of the Hall element displacement sensor. Finally, operation verification of the developed magnetic levitation system was conducted by designing state feedback regulator with observer.     

A Hydrogen‐Storage Distributed Generation System Using Unitized Reversible Cells and Its Operational Scheme

Environmental issues such as global warming and depletion of natural energy resources are posing problems. Photovoltaic systems have been attracting attention as a form of renewable energy. The output power of a photovoltaic system changes sharply because solar radiation intensity and temperature vary with the weather. In conventional photovoltaic systems, the surplus power, excluding the power consumed in the load, flows back to the grid. Therefore, fluctuations in the output power of a photovoltaic system may have an adverse effect on the grid. This paper proposes a novel hydrogen‐storage distributed generation system using a unitized reversible cell that integrates a fuel cell and water electrolyzer to smooth reverse power flow. The hydrogen‐storage distributed generation system was modeled and a computer simulation was performed. Using two evaluation methods, the proposed system is shown to be effective at leveling power flow back to the grid.     

Three-level incentive schemes using follower's strategies in differential games

We deal with three-level incentive differential games in which first and second leaders have access not only to slate information but also to information on follower's strategies. We derive sufficient conditions for three-level incentive schemes using information on follower's strategies in both linear and non-linear differential games, and show that three-level incentive schemes using information on follower's strategies depend on an initial state value.     

PHASE AND MORPHOLOGY OF PbNb2O6 OBTAINED BY MOLTEN SALT SYNTHESIS

ABSTRACT

The morphologic development of lead metanlobate powder particles in KC1 is examined with special emphases on the heating- conditions and starting compositions. Potassium ions are substituted in the Pb-x K_2xNb₂0₆(PKN) With the Sthorhoobic modifications.The.morophology of particles changed during PKN formation and particle growth. During the formation process of PKN, equiaxed and rod-shaped particles were obtained both above and below the melting temperature of KC1. The rod-shaped particles have a columnar structure but decrease in number with Increasing potassium content in the starting mixtures. During the growth process, equiaxed particles grew to simple rod-shaped particles without a columnar structure. Potassium in the starting oxide was found to promote the formation of simple rod-shaped particles. PKN powder composed of only simple rod-shaped particles is obtainable.     

Infrared Spectra of Rapidly Quenched Glasses in the Systems Li2O-RO-Nb2O5 (R=Ba, Ca, Mg)

Twin-roller quenching produced wide ranges of glass formation in the systems Li₂O-RO-Nb₂O₅ (R=Ba,Ca,Mg). The glass-forming ability is improved with an increase in the ionic radius of R²⁺ ions. The crystallization temperature is increased as Li₂O is replaced by RO or the ionic radius of R²⁺ ions is increased. Infrared spectra revealed that the glass LiNbO₃ (=50Li₂O-0Nb₂O₅) was composed of six-coordinated NbO₆ octahedra, which were joined together by corner-sharing only. In the Li₂O-RO-Nb₂O₅ glasses there exist edge-shared as well as corner-shared NbO₆ octahedra. The edge-shared NbO₆ octahedra in the glasses are increased with an increase in the content of RO or Nb₂O₅, and also with an increase in the ionic radius of R²⁺ ions.     

Reactions in the System ZrO2-SrO

The liquidus curve of the system ZrO₂-SrO was investigated with a heliostat-type solar furnace. The cooling curve of a specimen was obtained with a brightness pyrometer at 0.65 pm to determine the freezing point and other transition phenomena. The primary phases and the compounds formed in the system were also examined. The existence of Sr_gZr_a-1O_3x-2 (n=4, 3, and 2) and of SrZrO₂ was confirm. A tentative phase diagram of the system ZrQ₂-SrO at high temperatures is presented.