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     

日本の寒地，北海道におけるうるち米粒外観品質の育種（日文）（网络首发、推荐阅读）

北海道では旧来，米粒外観品質を東北以南に遜色ない程度まで向上させるため，乳白，腹白などの未熟粒が少なく整粒歩合や玄米と精米の白度が高くなるように，主に達観により選抜を行ってきた。その結果，1903年以降に育成された新旧品種では，整粒は育成年次が新しいほど概して多く，未熟粒，被害粒および着色粒は減少した。とくに，1961年育成の「ユーカラ」は，整粒歩合が同時代や以前の品種に比べ顕著に高く，系譜からみてその良質性はその後に育成された良質良食味米品種に受け継がれた。1984年以降に育成された主要品種は東北以南の銘柄米品種に比べ，整粒歩合がやや低く未熟粒歩合はやや高かった。玄米と精米の白度は，1971年より前の育成品種では腹白粒等の混入が多く，それが白度を上げるため育成年次と一定の関係が無かった。それ以降，両白度は新しい品種ほど高くなり，精米蛋白質含有率が低いほど高い傾向があった。現在の主要品種は東北以南の銘柄米品種に比べ，玄米白度はやや劣るが，精米白度，玄米透明度および精米透明度には明確な差異が無かった。さらに，整粒のみの玄米白度では，差異はなかった。以上から，現在の北海道主要品種の米粒外観品質は，東北以南銘柄米品種に比べ未熟粒がやや多く整粒がやや少ないことを除き，明確な違いはなくなった。     

The grindability and wear of Ti-Cu alloys for dental applications

To optimize the properties of titanium for use in dentistry, alloying is necessary. This study reports on the characterization of some titanium alloys for grindability, wear, and corrosion resistance. Improvements in grindability and wear seemed to occur with the presence of the eutectoid in the alloy. For more information, contact Toru Okabe, Baylor College of Dentistry, Dept. of Biomaterials Science, 3302 Gaston Ave., Dallas, TX 75246; (214) 828-8190; fax (214) 828-8458; e-mail tokabe@tambcd.edu.     

Network management in a local computer network

The functions and structure of the network management subsystem of the GAMMA-NET, a local computer network at the University of Tsukuba, are presented. The network management subsystem is an integrated subsystem that offers a convenient man-machine interface for the network users during the execution of required jobs, and levels the workload throughout the system, as well as managing the network operations.     

Enhanced Dispersion Frequency of Hot-Pressed Z-Type Magnetoplumbite Ferrite with the Composition 2CoO·3Ba0.5Sr0.5O·10.8Fe2O3

The high-frequency magnetic properties of strontium-partially-substituted Z-type magnetoplumbite with the composition 2CoO·3Ba_1-x.Sr_xO.yFe₂O₃ were studied using a hot-pressing technique. The best properties were obtained for a sample hot-pressed in oxygen, having x and y values of 0.5 and 10.8, respectively. The resonant frequency of that sample, corresponding to a μ" maximum reaching 2.5 GHz, was significantly larger than the value of 1.4 GHz previously reported for unsubstituted Z with the composition 2CoO·3BaO·12Fe₂O₃. This result implies that a new ferrite material, applicable in the gigahertz region, has been obtained.     

Analysis of irregular increase in sheet resistance of Ni silicides on transition from NiSi to NiSi2

The annealing conditions causing an irregular peak in sheet resistance of nickel silicides are investigated. It is found that the irregular rise in sheet resistance occurs at a critical temperature of 750-775 °C as a result of agglomeration related to phase transition from NiSi to NiSi₂. Experiments on the effect of temperature, heating rate and annealing duration in rapid thermal annealing revealed that the high-resistance state produced by annealing at the critical temperature could not be changed by subsequent annealing at higher temperature, and that the high-resistance state required 30-40 s at the critical temperature to form. Pre-annealing at 600 °C was found to suppress the later formation of the high-resistance state.