Three‐dimensional numerical analysis on discharge properties of microwave excited ring dielectric line surface wave processing plasma device

A three‐dimensional simulation code with the finite difference time domain (FDTD) method combined with the electron fluid model has been developed for the microwave excited surface wave plasma in the RDL‐SWP device. This code permits the three‐dimensional numerical analysis of the spatial distributions of electric field, power absorption, electron density, and electron temperature. At a low gas pressure (about 10 mTorr), the numerical results were compared with the experimental measurements that show the validity of this 3D simulation code. A simplified analysis assuming that the electron density is spatially uniform has also been studied and its applicability is evaluated by the comparison of the 3D simulation and the analytical solutions. The surface wave eigenmodes are determined by the electron density, and it is found that the structure of the device strongly influences the spatial distribution of the electric fields of surface waves in a low‐density area (n_e < 3.0 × 10¹¹ cm^?3). A method to irradiate by microwave the whole surface area of the plasma is proposed. The method is found to be effective in obtaining a high uniformity distribution of electron density. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 150(4): 1–12, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10333     

Sharing and Compatibility Study between Fixed Service Using High Altitude Platform Stations (HAPS) and Other Services in the 31/28 GHz Bands

In the World Radiocommunication Conference 2000 (WRC-2000), use of the 31 GHzand 28 GHz bands was permitted for the fixed service (FS) by using highaltitude platform stations (HAPS) in some countries. This paper examines thesharing and compatibility of the HAPS-based FS with the other services usingthe same and adjacent frequency bands and establishes the conditions of thecoexistence with those services. Feasibility of dynamic channel assignment(DCA) scheme among the different communication systems to facilitate thecoexistence is also studied.     

Stability and chaotic characteristics of a wall plume

In this study artificial disturbances were introduced into a wall plume adjacent to a vertical side wall, and its stability and chaotic characteristics were experimentally examined. The main results are: (1) for high and low frequency disturbances the neutral region (a region between stability and instability) is lower and higher values of the modified Grashof number than an analytical neutral curve, respectively. (2) As the Grashof number increases, a chaotic fluctuation of temperature is observed above a critical value. This chaotic region is completely included in the region where the wall plume is unstable. (3) The flow can be classified into four regions based on patterns, a stable region, disturbance-amplification region, chaotic region and non-chaotic region.     

Gas phase oxidation of benzene to phenol using Pd-Cu composite catalysts. Effect of temperature,feeding gas and catalyst composition

Catalytic oxidation of benzene in the gas phase has been studied as a function of the catalyst composition, reaction temperature and the feed conditions of reactant gases, hydrogen, oxygen, benzene as well as diluting inert gas. The catalyst tested is composed of Pd and Cu(I) ions, both of which are supported on silica gel. If one of the two metal species is lacked from the catalyst, no catalytic activity appears. The product is almost exclusively phenol and some accompanying benzoquinone, in particular at lower temperatures, as minor byproduct.On leave from Hua-Dong Institute of Technology, Nanjing, People's Republic of China.     

Morphology-Properties relationship of a ternary polymer alloy

A ternary alloy of polyamide-6 (PA), poly(phenyleneether) (PPE), and rubber has a three-phase structure, in which PPE particles with rubber inclusions are dispersed in a PA matrix. This is an excellent thermoplastic with high impact strength and high heat resistance. To understand the morphology-properties relationship, we undertook a two-dimensional finite element method (FEM) analysis on the deformation mechanism of the ternary alloy. A three-phase model was constructed so that five hybrid particles of PPE-shell and rubber-core were embedded in the PA matrix. When the model was deformed at room temperature, the rubber domain induced yielding of the PPE-shell and the PA-matrix and at large strains the yielded zone expanded to pervade the whole space. This suggests that the toughening mechanism is essentially the same as in the binary alloy of PA and rubber (rubber-toughened PA). At higher temperatures (e.g., at 100°C) the stress concentration occurred not only in the PA matrix but also in the PPE-shell. It implies that the PPE-shell is highly responsible for bulk deformation, even though it is part of the dispersed phase. At high temperatures, the rigidity of PPE affects the alloy bulk rigidity so that the ternary system exhibits high heat resistance.     

Deformation of Alumina/Titanium Carbide Composite at Elevated Temperatures

The deformation behavior of an Al₂O₃/30 wt% TIC composite in uniaxial tension was evaluated under vacuum over the temperature range of 1300° to 1550°C. The Al₂0₃/TiC composite exhibited the maximum elongation of 66% at an initial strain rate of 1.19 X l0^-4 s^-1 at 1550°C. The stress exponent calculated from peak stresses of true stress-true strain curves at 1500^OC was 3.8, which was in good agreement with that obtained by changing the crosshead speed during the tension test. The apparent activation energy at 20 MPa was 853 kJ/mol. In addition the deformation of the Al₂O³/TiC composite in uniaxial tension at elevated temperature was accompanied by cavitation.     

Modelling and prediction of phyto- and zooplankton dynamics in Lake Kasumigaura by artificial neural networks

An artificial neural network model was developed for Lake Kasumigaura to predict timing and magnitudes for chlorophyll a, five species of blue-green algae and three zooplankton groups. The model was trained by 8 years of limnological time series and validated by two independent years. The validation showed the potential of neural networks as predictive tools for highly non-linear phenomena such as blue-green algal blooms in freshwater lakes.     

Stress field near interface edge of elastic-creep bi-material

Stress fields on elastic-creep bi-material interfaces with different geometry of the interface edge are analyzed by finite element method. The results reveal that the stress highly concentrates near the interface edge at the loading instant and it gradually decreases as the creep-dominated zone expands from the small-scale creep to the large-scale creep. The stress singularity due to creep which resembles the HRR stress singularity appears near the interface edge in all cases. The stress intensity near the interface edge time-dependently decreases and becomes constant when the transition reaches the steady state. The magnitude is scarcely influenced by the edge shape of elastic material, though it depends on the edge shape of creep material. The stress intensity during the transition can be approximately predicted by the J-integral at the loading instant.     

Numerical simulation and PIV measurement of the flow-field in optical disc drives

A system of numerical flow simulation with an automated mesh generator and parallelized solver was developed and applied to the flow-field inside an optical disc drive. In this simulation system, a uniformly spaced Cartesian grid is used to reduce time and automatically generate a mesh from CAD data for complicated geometries, such as optical disc drives. The simulation results of optical disc drives are validated by particle image velocimetry (PIV) and pressure-distribution measurements. The measured velocity distributions above a rotating disc and around a pick-up unit show quantitative agreement with the simulated distributions. For the pressure distributions on a top case of an optical disc drive, although there is an error of 10% between simulated and measured results, the position of the peaks and distribution of pressure show good agreement. Comparing both sets of measurements, the simulation results in a Cartesian grid system are sufficiently accurate to enable the flow-field to be quantitatively assessed. This numerical flow simulation is applied to investigate the detailed flow-field in a commercial optical disc drive.     

日本彩色聚乙烯涂覆钢管的开发

试验了彩色聚乙烯涂覆钢管的耐腐蚀性和耐气候性，由于聚乙烯涂层隔绝水的作用，聚乙烯涂覆钢管具有优良的耐腐蚀性能，电阻绝缘值和优良的机械性能。建立了一个新的方式去研究分析聚乙烯抗老化剂消耗和在聚乙烯中的扩散。用有效测定的方法定量地预测彩色聚乙烯涂覆层的寿命，应用这些分析结果，不仅可使新的有色聚乙烯涂覆钢管在恶劣腐蚀环境介质情况下具有高的耐腐蚀性，而且有长的耐气候性。