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71.
H. Sawa Y. Wakabayashi R. Tazaki T. Kakiuchi K. Kanoda R. Kato 《Journal of Low Temperature Physics》2006,142(3-4):355-360
Synchrotron X-ray high-resolution measurements have been performed to investigate the nature of the insulating state of a
quarter-filled quasi-one-dimensional conductor (DI-DCNQI)2Ag and the π-d interacted conductor (DBr-DCNQI)2Cu. The two-fold structure in the ground state of (DI-DCNQI)2Ag system consists of not only charge ordering columns but also monotonic charge dimerized columns caused by frustration among
DCNQI columns. On the other hand, Cu salt in the insulating phase realizes a commensurate structure where the Cu charge ordering
is coupled with the 3c-CDW in the insulator phase. The frustration among charged columns is restrained by the charge ordering
of the Cu ions. 相似文献
72.
Kato K. Kurimoto M. Shumiya H. Adachi H. Sakuma S. Okubo H. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2006,13(2):362-372
Functionally graded materials (FGM) have spatial distribution of a material property in order to achieve efficient stress control. An application of the FGM to a solid insulator (spacer) for a gaseous insulation system, like gas insulated switchgear, is expected to improve electric field (E-field) distribution around the spacer. In this paper, we describe the applicability of the FGM spacer to gas insulated power equipment. In the FGM spacer, we gave spatial distribution of dielectric permittivity to control the E-field distribution inside and outside the spacer. This paper includes following key results for the applications of the FGM. Firstly, E-field simulation results when applying the FGM by a finite element method are presented, in which we show the effective reduction of the maximum field strength by applying the FGM. Next, a fabrication technique of the FGM spacer sample with not only step-by-step but also continuous changes of permittivity is presented by use of centrifugal force. Finally, dielectric breakdown tests using FGM samples which are accurately controlled the spatial distribution of permittivity are carried out under lightning impulse voltage applications. The test result indicates the increase of breakdown voltage (BDV). From these results, we verified the applicability and the fabrication technique of FGM spacer for improvement of the dielectric strength in the gaseous insulation system. 相似文献
73.
Weidong Ding Ryota Hayashi Kohei Ochi Junya Suehiro Kiminobu Imasaka Masanori Hara Noriaki Sano Eiichi Nagao Tadao Minagawa 《Dielectrics and Electrical Insulation, IEEE Transactions on》2006,13(6):1200-1207
Chemical byproducts analysis has been recognized as a powerful diagnosis method for SF6 gas-insulated switchgear (GIS). The authors have previously demonstrated that a carbon nanotube (CNT) gas sensor could detect partial discharge (PD) generated in SF6 gas. However, PD-generated decomposition gas species, which were responsible for the CNT gas sensor response, have not been identified yet. In this paper, two kinds of experiments were conducted in order to identify the responsible decomposition gas species. At first, the decomposition gas molecules adsorbed on CNTs were analyzed by Fourier transformation infrared (FTIR) spectroscopy. FTIR absorbance was observed around 735 cm-1 after CNTs were exposed to PD generated in SF6. In the second experiment, the CNT gas sensor responses to typical SF6 decomposition products (HF and SF4) were examined. The CNT gas sensor responded to these gases in the same way as to PD generated in SF6. SF4 response was larger than HF response. Based on these results, SF 4 and SOF2 emerged as candidates for the responsible decomposition gases. Electrochemical interactions between adsorbed gas molecules and CNT were discussed based on theoretical predictions of molecular orbital calculations. The calculation results suggested that both of SOF2 and SF4 could increase the CNT gas sensor conductance 相似文献
74.
Nobuhiko Hayashi Yusuke Kato Manfred Sigrist 《Journal of Low Temperature Physics》2005,139(1-2):79-96
The low-temperature shrinking of the vortex core (Kramer-Pesch effect) is studied for an isolated single vortex for chiral
p-wave and s-wave superconducting phases. The effect of nonmagnetic impurities on the vortex core radius is numerically investigated
in the Born limit by means of a quasiclassical approach. It is shown that in the chiral p-wave phase the Kramer-Pesch effect
displays a certain robustness against impurities owing to a specific quantum effect, while the s-wave phase reacts more sensitively
to impurity scattering. This suggests chiral p-wave superconductors as promising candidates for the experimental observation
of the Kramer-Pesch effect. 相似文献
75.
Suzuki K. Kato K. Hakamata Y. Okubo H. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2003,10(4):563-568
In order to investigate the charging mechanisms of solid dielectrics in vacuum, we constructed real-time and high-speed measurement systems for charge density, current pulse, light emission and applied voltage. By applying a negative DC ramped voltage to an electrode with a cathode triple-junction (TJ), we measured the temporal variation of surface charge accumulation and current pulse waveforms expressing the electron emission from TJ, by electrostatic probes. From the measurement results, we explain the step like charging process and propose an electron emission model by taking the electric field and its relaxation by charging into account. In addition, we elucidate the relationship between the charging process and the location of electron emission. 相似文献
76.
Okubo H. Wakamatsu M. Inoue N. Kato K. Koide H. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2003,10(6):956-962
The electrical insulation structure of most power transformers is a combination of insulating oil and solid materials. One of the crucial problems we face in transformer operation is flow electrification, which occurs at a flowing oil/solid material interface. Thus, for the transformer insulation design, we need to clarify the now electrification phenomena. In this paper, we measured the electric field strength in an oil/pressboard composite insulation system using an electro-optic method of the Kerr effect. We obtained the time variation of electric field distribution in both flowing uncharged and charged oil. It is notable that we could quantitatively clarify the electric field distortion in flowing charged oil by flow electrification. Furthermore, we measured the leakage current from divided electrodes and derived a charge density distribution along the flow direction. Finally, we quantitatively discussed the electric field distribution and the charge behavior from the measurement results. 相似文献
77.
Kim E.J. Kato G. Ohara T. Ohki Y. Li S.T. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1997,4(6):732-737
When polyethersulfone was irradiated by γ rays and then poled at 37°C, a new TSC (thermally stimulated current) peak appeared at ~100°C. This new peak and other peaks near 40 and 150°C increase with an increase in dose of ~0.6 kGy, and this is considered to be due to trapped charges and other ionic carriers becoming mobile when rearrangement of scissioned chains occurs. However, if the dose exceeds 0.6 kGy, the peak magnitude decreases. Furthermore, if the TSC was poled at 120°C, only the peak near 150°C appeared and this peak monotonically decreased with an increase in the irradiation dose. A similar decreasing tendency was also observed in the conduction current and in the residual voltage. These decreasing features are considered to be caused by the radiation-induced change that rearrangement of scissioned chains decreases free volume for ionic transport 相似文献
78.
The structural organization and fine distribution of the lymphatic networks in the periodontal tissues (gingiva, periodontal membrane, and alveolar process) and dental pulp of animals and humans were reviewed with special reference to histochemical examination by light and electron microscopy. The distinction between lymphatics and blood vessels was made on cryostat sections of undecalcified and calcified teeth treated with EDTA solution and whole mount preparations of periodontal membranes using 5'-nucleotidase (5'-Nase)-alkaline phosphatase (ALPase) double staining. This staining procedure allowed lymphatic vessels in the periodontal tissue and dental pulp to be differentiated from blood vessels. The specificity and localization of the enzyme reactions were confirmed by comparative histochemical studies of the same specimen with light microscopy and scanning or transmission electron microscopy. Well-developed 5'-Nase-positive lymphatic networks were observed on the tissue sections and whole mount preparations of the gingiva, periodontium, and dental pulp. More lymphatic vessels were seen in the root area of the periodontium than in the cervical area. In the dental pulp, lymphatic vessels were more numerous in the central part than in the peripheral odontoblastic layer. These distributions of the lymphatic capillary networks are discussed in relation to their ability to supply lymph to the teeth. 相似文献
79.
In-situ analysis for SiC bulk single crystal growth was reported using vertical X-ray diffractometer system. A furnace for SiC sublimation growth combined with the XRD system which possessed three kinds of functions including topography, rocking curve measurement and crystal growth rate monitoring was developed. These functions could contribute as a powerful tool finding the optimum growth condition by dynamic observation in the crucible. In this study, the in-situ X-ray topographs succeeded to capture dynamic elongation of defects and dislocation generated in the SiC growing crystals. The in-situ rocking curve measurement reviled appearance of mosaic structure in the SiC crystal grown with high growth rate. The in-situ growth rate monitoring also succeeded very precisely using the direct X-ray beam absorption. On the base of findings and facts obtained by the in-situ observations, the importance for the SiC growth was discussed. 相似文献
80.
Terutsugu Koya Yo Niida Misa Togi Kenichi Yoshida Takuya Sakamoto Hiroki Ura Sumihito Togi Tomohisa Kato Jr. Sohsuke Yamada Haruo Sugiyama Shigeo Koido Shigetaka Shimodaira 《International journal of molecular sciences》2022,23(20)
Malignant pleural effusion (MPE) provides a liquid tumor microenvironment model that includes cancer cells and immune cells. However, the characteristics of tumor antigen-specific CD8+ T cells have not been investigated in detail. Here, we analyzed MPE samples taken from a patient with pancreatic cancer who received a dendritic cell vaccine targeting Wilms’ Tumor 1 (WT1) antigen over the disease course (two points at MPE1st and 2nd, two months after MPE1st). Epithelial cell adhesion molecule (EpCAM)+ cancer cells (PD-L1− or T cell immunoglobulin mucin-3, TIM-3−), both PD-1 or TIM-3 positive CD8+ T cells, and CD14+CD68+CD163+TIM-3+ macrophages increased from the MPE1st to MPE2nd. The ratio of WT1-specific cytotoxic lymphocytes (WT1-CTLs) to MPE CD8+ T cells and IFN-γ secretion of WT1-CTLs were reduced with disease progression. Coincidentally, the fraction of central memory T (TCM) of WT1-CTLs was decreased. On the other hand, CD8+ T cells in response to SMAD4P130L, which is homogeneously expressed in EpCAM+ cancer cells, were detected using in vitro expansion with the HLA-A*11:01 restrictive SVCVNLYH neoantigen. Furthermore, the CD8+ T cell response to SMAD4P130L was diminished following remarkably decreased numbers of CD8+ TCM in MPE samples. In conclusion, CD8+ T cells responding to WT1 or SMAD4P130L neoantigen expressed in EpCAM+ pancreatic cancer cells were detected in MPE. A tumor antigen-specific immune response would provide novel insight into the MPE microenvironment. 相似文献