Breakdown mechanism of capacitively coupled RF discharges

Measured breakdown characteristics of capacitively coupled RF discharges are compared with numerical simulations performed under different boundary conditions at the electrode. When a pair of glass‐covered aluminum disks are used in the breakdown measurement of N₂ and Ar gases at RF frequency of 13.56 MHz, the peculiar bend in the left branch of the minimum of V‐shaped breakdown curves is not observed, suggesting the absence of secondary electron emission. For the treated boundary condition of the electron density n, the simulation with the zero gradient gives satisfactory agreement with the experimental V‐shaped curves, while the simulation with n = 0 is shown to be effective in the region of small electric fields. The development of RF breakdown is explained based on the simulation for spatiotemporal profiles of n. © 1999 Scripta Technica, Electr Eng Jpn, 130(1): 8–14, 2000     

Generalized fuzzy inference neural network using a self-organizing feature map

A new model for generalized fuzzy inference neural networks (GFINN) is proposed in this paper. The networks consist of three layers: an input-output layer, an if layer, and a then layer. In each layer, there are the operational nodes. A GFINN can perform three representative fuzzy inference methods by changing the connectivity and the operational nodes. There are three learning processes in a GFINN: a self-organizing process, a rule-integration process, and a LMS learning process. In the rule-integration process, a GFINN employs two feature maps in order to integrate appropriate rules effectively. Computer simulations were carried out to show the superiority of a GFINN over back-propagation networks. © 1998 Scripta Technica, Electr Eng Jpn, 125(3): 40–49, 1998     

Preparation of poly(amide-imide)s derived from biphenyltetracarboxylic dianhydrides

Four new diimide-dicarboxylic acids (I–IV) were prepared by condensation of s- or a-BPDA with para- or meta-aminobenzoic acid. A series of aromatic poly(amide-imide)s containing these diimide-dicarboxylic units was prepared by three methods: (1) acid chloride method, (2) triphenylphosphite method, and (3) one-pot method. A typical polymer of the series is readily soluble in polar aprotic solvents such as N-methyl-2-pyrrolidone (NMP), dimethylsulfoxide (DMSO), and pyridine (py) and could be cast into tough and flexible films. These were characterized by inherent viscosity, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) measurements. The glass transition temperatures of these polymers were in the range of 220–290°C, and the 5% weight loss temperatures were 450–500°C. Films prepared by casting from polymer solutions exhibited good tensile properties. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 865–873, 1997     

Nano-cell fabrication on InSb utilizing point defects behavior induced by focused ion beam

In ion irradiated GaSb, InSb and Ge, the induced point defects form voids and these voids develop to the cells by further irradiation. The nano-fabrication technique utilizing this behavior is performed on (100) InSb by focused Ga⁺ ion beam (FIB). Fabrication of nano-cell lattices with cell an interval of 30-300 nm are tried varying the acceleration voltage and the ion dose at room temperature, and the plan views and the cross-sectional views of the nano-cell structures are observed by scanning electron microscopy (SEM). The possible ranges of the cell interval, the cell diameter and the cell height are obtained from the results.     

Corrosion behavior of Ti-Ag alloys used in dentistry in lactic acid solution

The purpose of this study was to evaluate the corrosion resistance of experimental Ti-Ag alloys used as dental materials. An elution test and a rest-potential measurement of alloys with 5–30 mass.% Ag were performed in a 1 % lactic acid solution. The amount of Ti ions released from the α phase of the Ti-Ag alloys decreased as the Ag concentration increased. TiAg present in the alloys dissolved preferentially, but Ti₂Ag did not. The rest potentials of the Ti-Ag alloys were significantly higher than that of pure titanium. The elution test and the rest-potential measurement revealed that the Ti-Ag alloys, which formed a single α-titanium structure or contained a titanium and Ti₂Ag, had excellent corrosion resistance that was comparable or superior to that of pure titanium.     

Palladium-NHC catalyzed enantioselective synthesis of fused indolines via inert C(sp(3))-H activation

New sterically hindered chiral N-heterocyclic carbene (NHC) ligands were used in palladium catalysis to bring about a highly enantioselective C(sp(3))-H activation on the methylene site of a cycloalkane moiety. The intramolecular coupling reaction of a prochiral N-aryl-N-cycloalkyl methyl carbamate required high temperatures (140-160 °C) and afforded highly enantioenriched trans-2,3-fused indolines.     

Optimal Simulation of Distributed Generation System for CO_2-Reduction in Supermarket and Restaurant

After the great east Japan earthquake in 2011, Japanese energy system has been expected to prioritize safety and trustworthiness. Now, distributed power systems are considered as one solution, but utilizing exhaust heat is an important task to be solved. The purpose of this study is to build a simulation model to harness waste heat of commercial buildings. We obtained two types of data： distributed power system in 1/15 scale model of supermarket, restaurant and real world energy consumption of the two buildings. Results showed cold cabinets, whose electricity was affected by temperatures outside and inside, consumed most in supermarket. While air conditioning, affected by air enthalpy of outside and inside, consumed most in restaurant. According to our simulation with gas engine, PV （photovoltaic） panel, PCM （phase change material）, thermal storage, FCU （fan coil unit） and refrigerated cabinets in scale model, we could reduce 27% of CO_2 emission and 25% of running cost by selecting optimal size.     

Preparation of Air-Stable Iron-Oxide-Coated Metallic Iron Nanoparticles

The α-Fe nanoparticles with oxide shell were prepared by the complete reduction of iron oxide ones with hydrogen, followed by the selective surface oxidation as a thin layer. As-treated α-Fe nanoparticles preserved their saturation magnetization and metal α-Fe phase for at least 80 days in the air. In comparison, the unstabilized α-Fe nanoparticles protected only by their silica shell were oxidized instantly in the air and the saturation magnetization of the unstabilized α-Fe nanoparticles was decreased drastically. Since the stabilization procedure was carried out under dry conditions using silica-coated iron oxide nanoparticles as precursors, it could be applied to nanoparticles of various sizes and shapes to obtain a stable α-Fe phase.