Study on Magnetic Responsibility of Rare Earth Ferrite／Polyacrylamide Magnetic Microsphere

Magneticpolymermicrospherecanbeseparatedquicklyundermagneticfieldandithasgotwideappli cationinmanyfields ,suchascellseparationetc .Themicrospheremustpossesshighmagneticresponsibili ty ,sothatmagneticseparationisquickandconve nient.Themagneticresponsibilit…     

Preparation and Property of Acrylic Acid Rare Earth Complex and Its Hydrosilylation

Acrylic acid rare earth complex was prepared. Its chemical composition was determined by chemical and elemental analysis, and its structure as well as properties was characterized using IR, Fluorescence and UV spectrum, and its solubility was also investigated. Meanwhile a kind of elastic functional polymer with rare earth units in the side chains was produced. It is confirmed by IR spectrum that the Si-H bonds really react with acrylic acid rare earth.     

Spontaneous emission from a three-level atom placed in three-dimensional photonic crystals in the long-time limit

The paper describes the spontaneous emission from a three-level atom placed in a periodic dielectric microstructure which exhibits a complete three-dimensional photonic band gap. By using the Euler approach, the upper level population of the atom is calculated for a wide range of relationships between the Rabi frequency and the detuning of the atomic transition frequency from the upper band edge. The results indicate that there are three cases of the relationship between Rabi frequency and detuning, which determine distinctive states of the atomic population in the long-time limit. When the detuning is greater than the Rabi frequency, the upper level has a zero steady-state atomic population, which leads to enhancement of spontaneous emission. When the magnitude of the detuning is less than the Rabi frequency, the upper level has a nonzero steady-state atomic population, which leads to suppression of spontaneous emission. When the negative detuning is greater than the Rabi frequency, the upper level has a nondecaying oscillatory-state atomic population due to long-time atomic splitting. These three properties of the spontaneous emission are relevant to several optical devices on an atomic scale, such as optical memories, switches and clocks.     

Investigation of Water Tree Degradation in Dry‐Cured and Extruded Three‐Layer (E‐E Type) 6.6‐kV Removed XLPE Cables

Dry‐cured and extruded three‐layer (E‐E type) 6.6‐kV cross‐linked polyethylene (XLPE) cables were introduced into electric power systems more than 30 years ago, but they do not experience failures because of water tree degradation. Also, the degradation index of water treeing for these cables has not been established. Therefore, investigating results of residual breakdown voltage and water tree degradation of these cables will help us plan for cable replacement and determine water tree degradation diagnosis scheduling, and will be fundamental data for cable lifetime evaluation. In this study, the authors measured the ac breakdown voltages of dry‐cured and E‐E type 6.6‐kV XLPE cables removed after 18 to 25 years of operation and observed the water trees in their XLPE insulation. As a result, it was observed that breakdown voltages were larger than the maximum operating voltage (6.9 kV) and the ac voltage for the dielectric withstanding test (10.3 kV). Water trees were mainly bow‐tie water trees and their maximum length was approximately 1 mm. Although the number of measured cables was limited, the lifetime of this type of cable was estimated to be approximately 40 years, even experiencing water immersion.     

High pressure synthesis of HgBa2Ca2Cu3Oy without a precursor

Abstracts are not published in this journal     

Fermentation of Soy Sauce with Immobilized Whole Cells

Soy sauce was produced continuously for 80 days in 280 liter column-type reactors containing immobilized whole cells of Pediococcus halophilus, Saccharomyces rouxii, and Torulopsis versatilis entrapped in calcium alginate gels. The divided lactic acid and alcohol fermentation by viable cells of three kinds with feed solution obtained from enzymatic hydrolyzate of koji and defatted soybean meal proceeded in shorter time than a complex fermentation of moromi (soy sauce mash) in the slurry state. The refined products fermented by this process had good taste and flavor, and were close to the conventional soy sauce with respect to organic acid and aroma components.     

Effect of copper addition on the β-phase formation rate in FeSi2 thermoelectric materials

The transformation kinetics of the β-phase from an as-solidified structure composed of α and ε in the Fe–Si system was investigated by using rapidly, unidirectionally or conventionally solidified FeSi₂ alloys containing a small amount of Cu (0.1–1 at%). The addition of Cu decreased the size of primary ε and slightly changed the solidified eutectic morphology. The solubility of Cu in the α-Fe₂Si₅ phase was estimated to be less than 0.2 at%. A needle-like Cu enriched phase was newly formed in the conventionally solidified alloys containing more than 0.2 at % Cu. Microdifferential thermal analysis (DTA) clearly showed that the addition of Cu drastically accelerated β-phase formation. X-ray diffraction analysis and microstructural observation of the isothermally heat-treated specimens showed that Cu addition was effective in increasing the rate of eutectoid decomposition (α → β + Si) and the initial stage of the peritectoid reaction (α + ε → β). For complete β formation, heat treatment for a long time was still required because it took a long time for the coarse ε-phase in the slowly solidified alloy to be eliminated by peritectoid reaction. The effect of Cu depended on the annealing temperature. The decomposition rate of α in the Cu-added cast specimen was about 15 times higher at 1073 K than that of the binary cast specimen and exceeded more than 30 times at 873 K. This revised version was published online in November 2006 with corrections to the Cover Date.     

一种微小物体精密定位的直线微工作台

提出了一种基于平滑冲击驱动原理的精密定位直线微工作台.通过采用微小强磁铁作为摩擦元件,减小了由摩擦元件磨损而产生的摩擦力的变化,从而提高了微工作台的稳定性.设计制作了微工作台样机,并对精密定位工作台的动态特性和静态特性进行了实验研究.结果表明,微工作台体积小(20mm×10 mm×3 mm),可实现6 nm的精确定位,最高驱动速度可达5.4 mm/s,最大行程可达20 mm.     

东京电力公司采用特高压输电技术的论证经过

东京电力公司(Tokyo Electric Power Company,TEPCO)在20世纪90年代建成了1000kV南北输电线路和1000kV东西输电线路.文中介绍了日本选择特高压输电技术的经过和TEPCO采用特高压输电的必要性,指出了选择特高压交流最高运行电压时应考虑的因素;还对交流输电方式和直流输电方式进行了比较,分析了直流输电方式存在的问题,说明了TEPCO在特高压输电中采用交流输电方式的原因.对中国发展特高压输电有一定的借鉴意义.     

Effect of weld orientation on static strength and failure mode of friction stir stitch welds in lap‐shear specimens of aluminium 6022‐T4 sheets

Stitch friction stir spot welding (FSSW) is performed on 6022‐T4 Al alloy using a concave shoulder tool with cylindrical pin. Stitch FSSW is an extension of the conventional spot FSW process where an elongated (oval) spot is produced instead of a circular spot. The main advantage of this process is that it gives appreciably higher strength than conventional spot FSW due to an increase in the joint area. In this research, an experimental and numerical approach is taken to understand the failure mechanism of stitch welds made in lap‐shear configuration. There are four ways (orientations) in which specimens can be welded to produce a lap‐shear specimen – two in transverse direction and two in longitudinal direction. The static strength of welds made with these orientations was found to be different. For stitch welds made in the longitudinal orientation, the failure always occurred near the keyhole at the tool retract position. For welds made in the transverse orientation, failure always occurred in the region of the highest stress. This difference in the weld strength can be attributed to the hook geometry and interface bond strength. The results are explained using a kinked cracked model approach and calculation of stress intensity factor at the hook geometry.