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Volume 113, Issue 6
Displaying 1-8 of 8 articles from this issue
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Masayuki Izutsu1993 Volume 113 Issue 6 Pages 437-442
Published: June 20, 1993
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSDownload PDF (1130K) -
Hirokazu Tahara, Nobuki Uda, Yasuji Tsubakishita, Ken-ichi Onoe, Takao ...1993 Volume 113 Issue 6 Pages 443-452
Published: June 20, 1993
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSA simple computational code for simulating flowfields in direct-current arcjet generators was developed to understand inner discharge mechanisms and to clarify the correlation between operational characteristics and arc features in the discharge chamber. In this analysis, a quasi-one dimensional core-flow model including dissociation and ionization processes in thermodynamic equilibrium was used. The results showed that the arc radii for Ar gradually increased downstream in the constrictor and that the arcs attached to the constrictor wall. An increase in the mass flow rate for Ar located the arc attachment point more downstream. However, the arcs for N2 passed through the constrictor and did not attach even to the expansion nozzle because of dissociation process. The calculated arc features for Ar and N2 agreed with the experimental ones although a suitable interface condition between the arc and cold gas regions was required in the present analytical model.View full abstractDownload PDF (1244K) -
VII. Diffusion and reflection of metastable particlesSusumu Suzuki, Haruo Itoh, Hisashi Sekizawa, Nobuaki Ikuta1993 Volume 113 Issue 6 Pages 453-460
Published: June 20, 1993
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSAs is well known, the analysis of destruction processes of metastable particles in weakly ionized gas is made by solving the diffusion equation in which the diffusion and the collisional quenching are taken into account as loss processes. Previously, the Molnar type boundary condition which assumes zero density at the surface of electrodes was commonly adopted, and many experimental investigators have analyzed their data by such theory. However, we found sometimes that our experimental data fit to the theory not so well.
In order to solve the discrepancy, we adopted the third kind of boundary condition which can consider finite values for the density of the metastable particles at the surface of electrodes. Then, we confirmed the validity of our analysis by comparing our experimental data with the theoretical xpectations.
In this paper, we summarize the above mentioned theoretical treatment along with some of our experimental results.View full abstractDownload PDF (1401K) -
Yoshihiro Nagura, Yoshiharu Onuma, Kiichi Kamimura1993 Volume 113 Issue 6 Pages 461-466
Published: June 20, 1993
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSPolycrystalline silicon carbide (SiC) thin films were deposited by plasma enhanced CVD, using hydrogen diluted tetramethylsilane (TMS) as a source gas.
Remarkable peaks were observed in X-ray diffraction patterns of the SiC films prepared from diluted TMS. The XPS measurement showed that samples were stoichiometric composition when they were deposited at 800°C. The optical energy gap was estimated to be about 2.5eV from photo absorption measurements. The resistivity of the film was 10-1-100Ω•cm and the carrier Hall mobility in the film was about 10 cm2/V•s.
Piezoresistive property was measured by canti-lever method. The piezoresistive gauge factor was 7.5. A polycrystalline SiC/single crystal Si heterojunction diode showed well defined rectifying characteristics. The ideally (diode) factor was 1.5. These results show polycrystalline SiC films have promising properties as a material for electronic devices such as heterojunction bipolar transistor or piezoresistive sensor.View full abstractDownload PDF (825K) -
Xianggang Ji, Yuzo Takahashi, Shigeo Kobayashi1993 Volume 113 Issue 6 Pages 467-472
Published: June 20, 1993
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSThe authors observed contact charging of a PET film with a rubber roller, and a series of small electrostatic discharges between the layers of the charged film when the film is wound into a roll. In the contact charging with the rubber roller, the surface charge density of the film decreases as the roll becomes bigger. The surface potential of the roll, however, is increasing as the result of the integral of the charges. This results in the occurrence of the tree-like discharges. Moreover, small discharges occur at strongly charged areas of the film. Once the discharges occur at a layer of the film roll, they tend to occur at every outer layer of it, leaving short term (about 1-2mm), high density surface charges of opposite polarity on all these layers of the film in the roll.View full abstractDownload PDF (2302K) -
Makoto Katsumata, Hidenori Yamanashi, Hitoshi Ushijima, Morinobu Endo1993 Volume 113 Issue 6 Pages 473-479
Published: June 20, 1993
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSComposites containing carbon fibers have been studied and practically applied to various fields as carbon fiber reinforced plastic, while their electrical properties are not fully utilized. This paper focuses on the excellent conductivity and mechanical properties of the plastic composite based on the vapor-grown carbon fiber (VGCF) as a filler material. The electrical properties of the composites using ethylene vinylacetate as a matrix resin are studied and evaluated as electromagnetic interference (EMI) shielding material.
The resistivity of the VGCF composite is 2.0×10-1Ω•cm at room temperature. The composite in which the VGCF is added with electroconductive carbon black (CB) as mixing filler to matrix resin shows lower resistivity, 7×10-2Ω•cm, than the individual filler composites of VGCF or CB. The EMI shielding effect of the mixed filler composite is as high as 60dB for a sample with 2mm thickness.
The composites using VGCF are evaluated as highly conductive plastic materials with enough strength, which could be applied to advance EMI shielding technology.View full abstractDownload PDF (2044K) -
Satoru Maruyama, Shozo Kobayashi, Katsutoshi Kudo1993 Volume 113 Issue 6 Pages 480-485
Published: June 20, 1993
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSBranching structure of two-dimensional projected electrical trees in polymeric insulating materials is discussed from the viewpoint of fractal analysis. Samples in this investigation were polymethyl-methacrylate resin (PMMA) and cross-linked polyethylene (XLPE). The physical properties of XLPE samples were varied by the degree of cross-linking. The experiment was carried out under AC voltage application. The generated tree was photographed with a camera through a microscope. The obtained photograph was digitized by using a scanner and imageprocessed with a personal computer. After that, the tree length was measured and then the fractal dimension of tree was estimated using a scale covering method.
The results show that the electrical tree shape patterns, which were obtained from PMMA and XLPE specimens, are fractal objects and they can be quantified by means of fractal dimensions. Furthermore, the results show that there is a relationship between the degree of crosslinking of XLPE used and the fractal dimension of electrical tree patterns in XLPE.View full abstractDownload PDF (1962K) -
The Influence of Ambient N2 Gas PressureHirofumi Takikawa, Tomonori Fujishima, Tateki Sakakibara1993 Volume 113 Issue 6 Pages 486-487
Published: June 20, 1993
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSDownload PDF (670K)
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