A novel method for suppressing silicidation of tungsten catalyzer during silane decomposition in Cat-CVD

Growth of tungsten silicide (WSi_x) on tungsten (W) catalyzer surface is investigated by monitoring resistance change of heated W wire in silane (SiH₄) atmosphere. To know a method suppressing the silicide formation, the effect of carbonization of W surface is also studied. Resistance change of heated W, observed in initial stage just after SiH₄ introduction, is brought about increase in power consumption due to decomposition of SiH₄. This power consumption can be drastically reduced when W surface is carbonized. Therefore, carbonization of tungsten surface is effective to stabilize the catalyzer temperature and to suppress W silicidation.     

Current reliability issues and future technologies for systems on silicon – processes, circuits, chip architecture, and design

The progress of silicon technology is opening the era of “systems on silicon” in which a large-scale memory, a CPU, and other logic macros will be integrated on a single chip. These kinds of chips, called system LSIs, have an especially promising future in mobile and multimedia applications but face inherent technical problems related to the reliability of ultrathin oxide film, conflict in the processing of different components, increased gate and subthreshold leakage currents, memory bottlenecks, and design complexity. This paper reviews the system LSIs and then introduces related technologies in processing, circuits, chip architecture, and design. It also discusses the influence of the system LSIs on business strategies.     

Vibrationally Excited CO2 Formed in CO + NO Reaction on Pd(110) Surface in High Surface Temperature Range

The infrared chemiluminescence spectra of CO₂ formed during steady-state CO+NO reaction over Pd(110) indicated that the temperature of the bending vibrational mode was much higher than that of the antisymmetric one at higher surface temperatures such as 800–850 K. Especially, in the high temperature range, more vibrationally excited CO₂ was formed from CO+NO reaction than CO+O₂ reaction. On the basis of the result, we propose the model structure of reaction intermediates for CO₂ formation in CO+NO reaction, which is different from that in CO+O₂ reaction.     

A robot language for parts handling based on hierarchical structure of verbs

An operation-level robot language for parts handling has been developed, in which stress is laid on the systematization of the hierarchical structure of verbs (and verb phases) and the realization of and interpreter of the language for controlling a robot arm. In this research, the circumstances are defined as a robot arm, shelves (work benches), boxes and objects on a floor. In the user's programming, eighteen verbs can be utilized: [Level 3] place on, stack on, lift down, carry, direct to, put in, put out, push and draw; [Level 2] have, lift and put; [Level 1] go, raise, lower, seize (grip), detach and turn. In the system, a verb module is reduced to a sequence of the verb modules immediately one level below it, and a series of control commands to a robot controller is automatically generated.     

Anionic surfactants: lauric products

Lauryl sulfate and lauryl ether sulfate obtained by the sulfation of lauryl alcohol and lauryl alcohol ethoxylate are representative of anionic surfactants and are used as a formable detergent or an emulsifier. For the sulfation of lauryl alcohol and lauryl alcohol ethoxylate, SO₃ gas, it was found that the quality of products was significantly influenced by the reaction conditions. In order to obtain good quality products we developed a new technology by using a new type of reactor called a “climbing film reactor,” in which SO₃ gas and liquid raw material flow ascendingly.     

Position control for a linear slider with twin linear drives

In this paper, position control of a linear slider with twin linear drives is considered. Recently, for high‐speed response, several linear motors have been used for linear slider systems. In such a linear slider, if the linear drives are controlled individually, their position responses may undergo vibrational disturbance by interaction with the output of the motors. To control this vibration, this paper presents a dynamic model of a linear slider system which consists of two motion systems decoupled by coordinate transformation, and proposes a feedback controller which is designed for these two decoupled systems. The effectiveness of the proposed method is confirmed by experiments. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 147(4): 68–76, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10291     

Biomechanical Evaluation of Ti-Nb-Sn Alloy Implants with a Low Young’s Modulus

Dental implants are widely used and are a predictable treatment in various edentulous cases. Occlusal overload may be causally related to implant bone loss and a loss of integration. Stress concentrations may be diminished using a mechanobiologically integrated implant with bone tissue. The purpose of this study was to investigate the biomechanical behavior, biocompatibility and bioactivity of a Ti-Nb-Sn alloy as a dental implant material. It was compared with cpTi. Cell proliferation and alkaline phosphatase (ALP) activity were quantified. To assess the degree of osseointegration, a push-in test was carried out. Cell proliferation and ALP activity in the cells grown on prepared surfaces were similar for the Ti-Nb-Sn alloy and for cpTi in all the experiments. A comparison between the Ti-Nb-Sn alloy implant and the cpTi implant revealed that no significant difference was apparent for the push-in test values. These results suggest that implants fabricated using Ti-Nb-Sn have a similar biological potential as cpTi and are capable of excellent osseointegration.     

Fiber volume control of composite materials by loss angle

Fiber volume plays a critical role in achieving stable mechanical and physical properties in composite structures. This study develops a method to control this parameter in carbon fiber reinforced plastics (CFRPs) on the basis of the viscoelastic character of the thermosetting matrix resin. This method relies on the loss angle δ to quantitatively control fiber volume. CFRP flat panels are manufactured at varying initiating times of pressure application depending on the δ value of the CFRP matrix resin. An analysis of the manufactured panels clearly shows that the target fiber volumes can be obtained at an appropriate δ range. Specifically, CFRP fiber volumes can be controlled through the loss angle of the matrix resin. Defining this δ range is very important for establishing mechanically and physically stable CFRP structures. POLYM. COMPOS., 37:1307–1311, 2016. © 2014 Society of Plastics Engineers     

Polymer-derived β-SiAlON:Eu2+ phosphors

A series of β-SiAlON:Eu²⁺ phosphors were synthesized from single-source precursors, perhydropolysilazane chemically modified with Al(OCH(CH₃)₂)₃, AlCl₃, and EuCl₂. The single-source precursors were converted to β-SiAlON:Eu²⁺ phosphors by pyrolysis under flowing N₂ or NH₃ at 1000°C, followed by heat treatment at 1800°C under an N₂ gas pressure at 980 kPa. By varying the molar ratio of the chemical modifiers, β-SiAlON:Eu²⁺ with the compositions close to the theoretical ones expressed as Si_6−zAl_zO_z−2yN_8−z+2y:yEu²⁺ were synthesized, where the z values and Eu²⁺ contents were controlled in the ranges of .44–.78 and .35–1.48 mol%, respectively. The polymer-derived β-SiAlON:Eu²⁺ phosphors exhibited green emission under excitation at 460 nm attributed to the 4f⁷–4f⁶(7f³)5d¹ transition of dopant Eu²⁺. High-angle annular dark-field-scanning transmission microscopy analysis confirmed that the doped-Eu²⁺ existed interstitially within the channels along the c axis of host β-SiAlON. Compared with the conventional powder metallurgy route, the polymer-derived ceramic route in this study offers some advantages in the grain growth of host β-SiAlON and photoluminescence properties in terms of green emission intensity under excitation at 460 nm, and the highest intensity was achieved for the polymer-derived β-SiAlON:Eu²⁺ with z = .64 and .37 mol% Eu²⁺.     

Purification and characterization of an extracellular alpha-neoagarooligosaccharide hydrolase from Bacillus sp. MK03

An agarolytic bacterium was isolated from soil in Gifu prefecture, Japan, and identified as Bacillus sp. strain MK03. The strain secreted neoagarooligosaccharide hydroluse into the culture medium. The enzyme was purified 49.7-fold from the culture fluid by ammonium sulfate precipitation and anion-exchange and gel-filtration column chromatographic methods. The purified enzyme appeared as a single band on polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate (SDS)-PAGE. Estimations of the molecular mass by gel filtration and SDS-PAGE gave values of 320 kDa and 42 kDa, respectively, indicating that the enzyme is octametric. The enzyme cleaved the alpha-1,3 linkage in neoagarobiose to produce 3,6-anhydro-L-galactose and D-galactose. It also selectively cleaved the alpha-1,3 linkage at the nonreducing end in neoagarotetraose or neoagarohexaose to give 3,6-anhydro-L-galactose and agarotriose or agaropentaose. The optimum temperature and pH for the enzyme were 30 degrees C and 6.1, respectively. The N-terminal amino acid sequence showed no homology to sequences of other known neoagarooligosaccharide hydrolases and agarases.