Synthesis of BaAl2S4:Eu2+ Electroluminescent Material by the Polymerizable Complex Method Combined with CS2 Sulfurization

Eu-activated BaAl₂S₄ (BaAl₂S₄:Eu) blue light emission phosphor has attracted considerable attention recently as a prospective material for full color electroluminescent display applications. Although BaAl₂S₄:Eu was discovered over 30 years ago, the solid-state reaction between metal sulfides in sealed quartz ampoules remains the main method for the synthesis of this material. In this work, a homogeneous single-phase Ba_0.95Eu_0.05Al₂S₄ (BaAl₂S₄:Eu) phosphor was obtained by the sulfurization–reduction of the multicomponent oxide precursor in a CS₂ atmosphere at 1050°C. The oxide precursor containing barium, aluminum, and europium for this process was prepared by the polymerizable complex method, which ensures a high degree of homogeneity in the final product. The BaAl₂S₄:Eu material thus obtained exhibited a single emission line at 475 nm and a fluorescence intensity of 35% compared with one of the best commercially available (Ba,Eu)MgAl₁₀O₁₇ phosphors.     

Liquid-fuel combustion in a narrow tube using an electrospray technique

This study experimentally investigated the possibility of stable burning conditions of liquid fuel inside a narrow tube using an electrospray technique without external heating or a catalyst. The mixture of 30% volume ethanol and 70% volume n-heptane was used as a liquid fuel atomized by the electrospray method with single capillary-ring extractor-mesh collector electrode configuration placed inside a quartz glass tube with an inner diameter of 3.5 mm. A stable flame was established inside the narrow tube without wall wetting within a certain range of equivalence ratio for a fuel flow rate of 1 mL/h. This study confirmed that the role of the mesh as the collector was very important in establishing a stable flame inside the narrow tube. If the fuel flow rate was sufficiently large, wall wetting occurred and eventually stable burning stopped.     

Structural Changes of Scandia-Doped Zirconia Solid Solutions: Rietveld Analysis and Raman Scattering

Powder X-ray diffractometry (XRD) and Raman scattering measurements were used to study the structural changes of compositionally homogeneous metastable ZrO₂ solid solutions induced by ScO_1.5 doping. The crystal structures of monoclinic, tetragonal, cubic, and rhombohedral (Sc₂Zr₇O₁₇, ß-phase) solid-solution phases have been refined by using the Rietveld analysis of the XRD data at room temperature of arc-melted ZrO₂- X ScO_1.5 ( X = 0, 2, …, 20, and 22 mol%) samples. The results can be interpreted as indicating that the structures of the monoclinic and tetragonal phases approach those of the tetragonal and cubic phases, respectively, by ScO_1.5 doping. Raman scattering, as well as XRD, was useful to investigate the phase assemblage. Moreover, we could obtain Raman spectra of the ß-phase probably for the first time.     

数控机床的防碰撞系统

当今世界的制造业正面临着高附加价值加工的转换,复合加工机、5轴联动机床、5面体加工中心等最新加工设备层出不穷。但是在加工车间,随着这些以复合加工机为代表的机械结构的复杂化,机械运动和机械操作也越来越复杂。在机加工操作中,刀具和工件以及夹具的干涉、机床单元的干涉比以前更加易于发生,需要操作工小心和熟练地操作。因此,迫切需求让机床操作工安全操作的机床。     

Microprocessor-Based Decoupled Control of Manipulator Using Modified Model-Following Method with Sliding Mode

A methodology of discontinuous feedback and continuous feedforward control is developed to achieve accurate decoupled tracking in a class of nonlinear, time varying systems in the presence of disturbances, parameter variations and nonlinear dynamic interactions. The method is based on an improved variable structure control with a sliding mode.     

Evaluation of the Fatigue Characteristics of Laser-processed Hot Work Tool Steel Based on Reliability

It is reported that laser-processing is effective to repair the heat checks, which are fine shallow cracks on a surfaceof die-casting dies.     

Evaporation-induced pattern formation in polymer films via secondary phase separation

The ordered necklace-like or cellular pattern formation has been investigated for ternary polymer solutions in which primary and secondary phase separations were induced by the solvent evaporation. The patterns consisted of regular droplet arrays of various diameters, which arose in the pre-existing polymer phases via the secondary phase separation. The pattern formation was enhanced with increasing air velocity and ambient humidity, while it was suppressed with decreasing initial film thickness. The regular pattern was independent of surface wettability of the solid substrate. We ascribe the morphology change to the evaporation-induced surface tension driven convection, which re-arranged the droplet distributions from disordered to flow-induced ordered patterns.     

Effects of gomisin A on the promotor action and serum bile acid concentration in hepatocarcinogenesis induced by 3'-methyl-4-dimethylamino-azobenzene

The effects of gomisin A, a lignan component of Schizandra fruits, on the promotion stage of hepatocarcinogenesis initiated by 3'-methyl-4-dimethylamino-azobenzene (3'-MeDAB) in male Donryu rats were investigated. When different types of tumor promotors, phenobarbital (PB) and deoxycholic acid (DCA), were administered for 5 weeks after initiation by 3'-MeDAB, preneoplastic alterations in the liver, determined by glutathione S-transferase placental form (GST-P), were markedly increased. Gomisin A significantly inhibited the increase in number and size of GST-P positive foci, regardless of the promotor. This lignan inhibited the increase in serum bile acid concentration by administration of DCA, but hardly influenced the serum bile acids in the PB-combined group. These results suggest that the inhibitory effect of gomisin A on the promotive action of DCA is based on improving bile acid metabolism, but regarding the action of PB, the effect could not be elucidated from the metabolism of bile acids.     

Molecular dynamics simulation of dislocation nucleation and motion at γ/γ′ interface in Ni-based superalloy

Molecular dynamics simulations are conducted on the dislocation behavior at the apices and edges of cuboidal Ni₃Al precipitate in a pure Ni matrix, or the idealized γ/γ′ microstructure in a Ni-based superalloy. A tensile simulation of the [001] direction is implemented with a periodic cell that has eight cubic precipitates in order to investigate the nucleation site of dislocation in the idealized microstructure with no defects other than the γ/γ′ interfaces. The effect of residual internal stresses on the stability of the interfaces is also discussed. Other simulations are conducted on the behavior of edge dislocations nucleated from a free surface and proceeding in the γ matrix toward γ′ precipitates under shear force. Dislocation pinning at γ′ precipitates, bowing-out in the γ channel, pile-up and nucleation of superdislocation in the γ′ precipitate are simulated and inspected in detail. Discussions on the size of the γ/γ′ microstructure and the sharpness of the edge of the γ′ precipitate are also presented.     

Three-dimensional waveguide arrays for coupling between fiber-optic connectors and surface-mounted optoelectronic devices

This paper describes the fabrication of novel surface-mountable waveguide connectors and presents test results for them. To ensure more highly integrated and low-cost fabrication, we propose new three-dimensional (3-D) waveguide arrays that feature two-dimensionally integrated optical inputs/outputs and optical path redirection. A wafer-level stack and lamination process was used to fabricate the waveguide arrays. Vertical-cavity surface-emitting lasers (VCSELs) and photodiodes were directly mounted on the arrays and combined with mechanical transferable ferrule using active alignment. With the help of a flip-chip bonder, the waveguide connectors were mounted on a printed circuit board by solder bumps. Using mechanical transferable connectors, which can easily plug into the waveguide connectors, we obtained multi-gigabits-per-second transmission performance.