Interfacial structure and reaction mechanism of AlN/Ti joints

Bonding of AlN to Ti was performed at high temperatures in vacuum. The bonding temperature ranged from 1323 to 1473 K, while the bonding time varied from 7.2 up to 72 ks. The reaction products were examined using elemental analysis and X-ray diffraction. TiN, Ti3AlN (τ1), and Ti3Al were observed at the AlN/Ti interface, having various thickness at different bonding conditions. The thickness of TiN and Ti3AlN layers grew slowly with bonding time. On the other hand, growth of the Ti3Al layer followed Fick’s law. The activation energy of its growth was found to be 146 kJ mol-1. When thinner Ti foil (20 μm) was joined to AlN at 1473 K for a long time (39.6 ks), the Ti central layer has completely consumed and another ternary compound Ti2AlN(τ2) started to form. A maximum bond strength was achieved for an AlN/Ti (20 μm) joint made at 1473 K for 28.8 ks, after which the bond strength of the joint deteriorated severely. This revised version was published online in November 2006 with corrections to the Cover Date.     

Effect of Filler Composition on the Brazing of Alumina to Copper Using Ultrasonic Wave

An ultrasonic wave was applied during brazing of alumina to Cu. First alumina was metallized by applying ultrasonicwave in braze bath. Then the metallized alumina was brazed with Cu using the same filler alloy. The filler used wereZn-Al alloys and Zn-Sn A     

Thermal Conductivities of As-Se Glasses

The thermal conductivities of As-Se glasses (0 to 50 at.% As) were measured by a comparative continuous-heating method from room temperature to above the glass transition. Thermal conductivity increased slowly with increasing temperature, then, in the transition region, decreased suddenly, reaching minimum values. Thermal conductivity at 40°C, as a function of composition, exhibited a maximum at 40% As.     

The Effect of Annelation on the Colour of 1, 4-Disubstituted Benzoanthraquinone Disperse Dyes

The visible spectra of a series of 1,4-disubstituted benzoanthraquinone dyes in benzene solution has been measured. The position of the absorption maxima of the dyes has been found to be well correlated with a mean ionization potential of the substituent groups. An annelation of anthraquinone dyes in the position of 2, 3 or 6, 7produced a small hypsochromic shift, while 5,6-annelation produced a large bathochromic shift. The additive properties on the absorption maximum of dibenzoanthraquinone dyes were also observed.     

Gelation of Bovine Serum Albumin by Glutathione

Bovine serum albumin (BSA) formed an opaque gel when incubated at 37°C with reduced glutathione (GSH). Gelation was highly dependent on concentration of GSH and pH, at 70 mM GSH and pH 8.2 BSA showed maximum gel hardness. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and the number of protein sulfhydryls revealed that gelation involves reduction of intramolecular disulfides in BSA and subsequent cross-links through intermolecular protein disulfides. Gelation was strongly inhibited by high concentrations of salts; inhibitory effects were highly dependent on species of anions, but not cations.     

Lead Zirconate Titanate Film Formation Technology with Use of Spray Coating Method

This paper presents a three-dimensional microfabrication and integration technology for MEMS smart materials that utilizes a spray coating method. Spray coating is shown to be most effective for additional deposition on non-planar surfaces. PZT films were formed both on flat and uneven surfaces at a thickness of about 1μ m. Perovskite structures were formed with suitable heat treatment and ferroelectric P-E hysteresis loop was also obtained. This paper is the first report from our group and other researchers on the deposition of smart materials for MEMS using a spray coating method. Spray coating has been proposed as an effective three-dimensional coating method which can be used to deposit piezoelectrics, pyroelectrics, magnetics, etc. for sensors and actuators. The hydrophilic and hydrophobic properties between the substrate surface and ejected liquid are most essential process factors in the spray coating method for improving the film growth conditions.     

Quality Evaluation of Fish Meat by 31 Phosphorus-Nuclear Magnetic Resonance

³¹Phosphorus-Nuclear Magnetic Resonance (³¹P-NMR) was used to evaluate degree of freshness of loach muscle depending on metabolic changes of high energy phosphate compounds. The phosphocreatine ([PCr])/inorganic phosphate ([Pi]) ratio was found to be a sensitive index of early metabolic hypofunction. Ratios of [PCr]/β-phosphate of ATP ([β-ATP]), and [Pi]/[β-ATP] were demonstrated to be appropriate indexes to estimate such metabolic changes in fresh fish. The intramuscular levels of creatine phosphate, ATP and pH were maintained at higher levels in blood-drained loach than in untreated fish. The freshness of fish which were bled and washed at lower temperatures were better preserved.     

EFFECT OF ALKYL CHAIN LENGTH OF 3-ALKYLPENTANE-2, 4-DIONE ON THE EXTRACTION OF COPPER

The equilibrium and kinetics of the extraction of copper with 3-alkylpentane-2, 4-dione (-H, -C₂H₅, -Ph, and -C₈H₁₇) were studied. It was found that the overall equilibrium constant is related to the proton disscoiation constant and that the ratio of the stability constants of the copper chelate, β₂/β₁ ²was independent of the alkyl chain length of the β-diketone. The rate constants for the reactions between cupric ion and the β-diketones in the aqueous phase were obtained by the relaxation method. The values decreased in the order -H>-Ph>-C₂H₅. The observed extraction rates were explained by a kinetic model using the measured physicochemical properties.