Effect of gas composition on the deposition of ZrC-C mixtures: The bromide process

Mixtures of ZrC-C were chemically vapour deposited from gaseous mixtures of zirconium bromides, methane, hydrogen and argon. The effect of gas composition on the deposition behaviour was studied. The experiments have shown that the methane concentration in the feed gas mixture is a crucial factor in determining the deposition rate and the character of the deposit. Chemical equilibria in the Zr-C-H-Br system were calculated and compared with the experimental results.     

Effects of crystal orientation on bendability of aluminum alloy sheet

We investigated the effects of crystal orientation on the bendability of aluminum alloy sheets by experiments using single crystal specimens and finite element analysis using a crystal plasticity model. In the experimental investigation, single crystal specimens having cube and Goss orientations were made from a coarse-grained Al-Mg-Si alloy sheet. The cube single crystal specimens have shown an excellent bendability regardless of the bending direction. Meanwhile, the bendability of the Goss single crystal specimens strongly depended on the bending direction. The finite element analysis results are remarkably consistent with the experimental results.     

Electrical responses of chalcogenide films in the photodoping process

The photodoping process in Al/AsS₂/Ag tri-layer films has been studied through measurements of electrical impedance, photodoped-layer thickness, and photocurrent. Frequency dependence of the impedance suggests that the sample under photodoping can be approximated by an equivalent electrical circuit. A thickness of photodoped layers, which is estimated from the impedance, is in agreement with a geometrical thickness measured by an atomic force microscope for chemically etched samples. Under the photodoping (with zero bias voltages), a photocurrent remains constant at ~ 5 pA, and near the completion it increases to ~ 1 nA, which is followed with a gradual decrease. By applying a bias voltage between the top (semi-transparent Al) and bottom (Ag) electrodes, we can change a photodoping rate by an order. This rate change is attributable to the modulation of an effective electric field in the doped layer, which induces the motion of Ag ions.     

Recognition and effective degradation of 17beta-estradiol by anti-estradiol-antibody-immobilized TiO(2) nanoparticles

Polyelectrolyte polyacrylic acid (PAA), used in the chemical modification of titanium dioxide (TiO(2)) nanoparticles, allows TiO(2) nanoparticles to remain in suspension at neutral pH. The anti-17beta-estradiol (E2) antibody was immobilized on PAA-modified TiO(2) (PAA-TiO(2)) nanoparticles via covalent bonding between the carboxylic acid of PAA and the amino group of the antibody. The anti-E2-antibody-immobilized TiO(2) (E2Ab-PAA-TiO(2)) nanoparticles can form a suspension at neutral pH, with a particle size of less than 100 nm. The E2-PAA-TiO(2) nanoparticles caused the photocatalytic degradation of a typical TiO(2) substrate, methylene blue. The anti-E2 antibody immobilized on the TiO(2) surface recognized and bound E2 in the solution, thereby improving the efficiency of E2 degradation compared with that of PAA-TiO(2) nanoparticles. These results demonstrate that the E2Ab-PAA-TiO(2) nanoparticles developed in this study can be used in water treatment technology. Furthermore, this strategy of immobilizing proteins on nanoscale TiO(2) particles creates new applications not only in the treatment of environmental waste, but also in medical and public sanitation processes.     

Low temperature preparation and machinability of porous ceramics from talc and foamed glass particles

Porous ceramics were prepared by firing mixtures of talc (Mg₃Si₄O₁₀(OH)₂) and foamed glass particles (ceramic balloons, CB) with and without LiCl as a sintering acid. The mixing ratios of the starting materials were talc:CB = 7:3, 8:2, 9:1 and 10:0, with additions of LiCl of 0, 2 and 5 mass%. The mixtures were formed into pellets and fired at 600–1000 °C. The pellets without LiCl showed very poor strength even when fired at 1000 °C but those containing LiCl were much stronger, even when fired at only 600 °C. The crystalline phases in these samples changed to enstatite (MgSiO₃) at ≥ 700 °C by decomposition of the talc under the fluxing action of the LiCl. The resulting samples were machinable and easily cut and drilled. The cutting rate decreased with increasing bending strength, for example, from 105 mm²/s and 6.3 MPa to 50 mm²/s and 16.3 MPa, respectively. The drilling rate of the present sample was found to be only slightly less than Teflon (polytetrafluoroethylene, PTFE) but much faster than graphite, glass ceramics, etc.     

Synthesis of Cubic Boron Nitride by Decomposition of Magnesium Boron Nitride

Cubic boron nitride ( c -BN) was synthesized by the decomposition of Mg₃BN₃ under high pressure and high temperature. The minimum pressure for c -BN synthesis was 4 GPa, which was 1 GPa lower than that of the conventional catalytic process. The decomposition of Mg₃BN₃ was observed only when H₂O was added. Therefore, the reaction was as follows: Mg₃BN₃+ 3H₂O = 3MgO + c -BN + 2NH₃. The c -BN crystals obtained were tetrahedron in shape and about 10 μ m in diameter.     

A mixed dispatching rule approach in FMS scheduling

Short-term scheduling in flexible manufacturing systems (FMSs) is a difficult problem because of the complexities and dynamic behavior of FMSs. To solve this problem, a dispatching rule approach is widely used. In this approach, however, a single dispatching rule is usually assigned for all machines in a system during a given scheduling interval. In this paper, a mixed dispatching rule which can assign a different dispatching rule for each machine is proposed. A search algorithm which selects an appropriate mixed dispatching rule using predictions based on discrete event simulation is developed for this approach. The search algorithm for the mixed dispatching rule is described in detail. The effectiveness (in meeting performance criteria) of the mixed dispatching rule and the efficiency of the search algorithm relative to exhaustive search (complete enumeration) is demonstrated on an FMS model. The mixed dispatching rule approach performs up to 15.9% better than the conventional approach, and is 4% better on average. The statistical significance of the results is dicussed.     

Upregulation of the elongation factor-1alpha gene by p53 in association with death of an erythroleukemic cell line

Genes upregulated by p53 were screened using an erythroleukemic cell line (1-2-3) that expresses only the temperature-sensitive p53 by the mRNA differential display method. One of the upregulated genes was identified as the elongation factor-1alpha (EF-1alpha) gene, an essential component of the eukaryotic translation apparatus. Three p53-responsive elements were found in the mouse EF-1alpha gene and in the corresponding human, rat, and frog genes. These elements conferred the capacity for induction by p53. EF-1alpha is also a microtubule-severing protein. Upon the temperature-shift, the cells developed the morphology and the localization of alpha-tubulin similar to those of the cells treated with vincristine, a drug that affects microtubules. The microtubule-severing associated with upregulation of EF-1alpha by p53 may be a cause of the cell death.