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排序方式: 共有379条查询结果,搜索用时 629 毫秒
61.
Hideyuki Yamamoto Toshiya Minejima Ichiro Sumitani Soji Kojima Takato Fukano Takamitsu Tada 《Electrical Engineering in Japan》1999,127(1):1-10
Grounding wires and enclosed ZnO elements have been incorporated generally in 6.6‐kV distribution systems by TEPCO for the reduction of lightning overvoltages. At present, the reliability to lightning surges is tolerably good. However, the facility of grounding wires is not inexpensive and its maintenance is hard due to corrosion and disconnection in some areas. A typical model simulating TEPCO field adopting enclosed ZnO elements has been developed and we have evaluated relative failure risks systematically according to conditions with and without grounding wires against lightning overvoltages. Two kinds of failures discussed in the paper are the flashover of insulation and the overduty of ZnO elements, and two kinds of induced and direct lightning overvoltages are studied in flashover. The greatest problem with no grounding wire is the increase of ZnO elements' duty, but it was demonstrated that a short partial grounding wire around ZnO elements or the selection of heavier ZnO elements provides a solution. The main objectives of this study are to clarify the relative failure risks systematically according to realistic field conditions, the risk of small stroke currents having long duration to ZnO elements' duty, and countermeasures against ZnO elements' overduty. © 1999 Scripta Technica, Electr Eng Jpn, 127(1): 1–10, 1999 相似文献
62.
We have developed a method to detect specific proteins with a high sensitivity using a gel electrophoresis method and force measurement of atomic force microscopy (AFM). Biotinylated proteins were separated by electrophoresis and fixed with cross-linking chemicals on the gel, followed by direct force measurement between the biotinylated proteins on the gel and a streptavidin-modified tip of an AFM cantilever. We were able to achieve a high enough sensitivity to detect the picogram order of the biotinylated proteins by evaluating the frequency of the interaction force larger than 100 pN in the force profile, which corresponds to the rupture force of interaction between streptavidin and biotin. 相似文献
63.
Strain-specific PCR primers for Lactococcus lactis subsp. cremoris FC were developed using the randomly amplified polymorphic DNA (RAPD) technique. RAPD was used to generate strain-specific markers. A 1164-bp RAPD marker found to be strain-specific was sequenced, and a primer pair specific for L. lactis subsp. cremoris FC was designed. The specificity of this primer pair was tested with 23 L. lactis subsp. cremoris strains and 20 intestinal bacterial species, and was found to be strain-specific. Subsequently, this primer pair was subjected to the quantification of L. lactis subsp. cremoris FC in the feces of subjects fed fermented milk containing this strain. After administration, L. lactis subsp. cremoris FC was detected in the feces of all 7 subjects, with the maximum number being between 10(5) and 10(9) cells g(-1) of feces. Furthermore, this strain was detected in only one feces sample 2 weeks after administration was stopped. These results suggest that L. lactis subsp. cremoris FC can survive passage through the gastrointestinal tract. 相似文献
64.
Interaction control between endohedral metallofullerene and metal substrate by introducing alkanethiol self-assembled monolayer 总被引:1,自引:0,他引:1
Yasutake Y Shi Z Okazaki T Shinohara H Majima Y 《Journal of nanoscience and nanotechnology》2006,6(11):3460-3463
The interaction control between endohedral metallofullerenes and a metal substrate has been demonstrated by introducing hexanethiol, octanethiol, and decanethiol self-assembled monolayers (SAMs) as the interlayer. We observe the electric properties of terbium endohedral metallofullerenes (Tb@C82) on alkanethiol SAMs with different chain lengths by scanning tunneling microscopy (STM) and spectroscopy (STS). Based on the comparison of the high-resolution STM images of a Tb@C82 molecule on hexanethiol and octanethiol SAMs, the interaction between Tb@C82 and a hexanethiol SAM is found to be larger than that between Tb@C82 and an octanethiol SAM; this is because at 68 K, the rotational states of Tb@C82 terminate only on the hexanethiol SAM. Furthermore, we find that the tunneling current-voltage characteristics of Tb@C82 on the hexanethiol SAM show the rectifying effects that are also caused by the molecular energy level shifts of Tb@C82 molecules due to the large interaction. 相似文献
65.
Daisuke Yokoyama Ken‐ichi Nakayama Toshiya Otani Junji Kido 《Advanced materials (Deerfield Beach, Fla.)》2012,24(47):6386-6386
66.
Kewei Liu Makoto Sakurai Masakazu Aono 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(23):3599-3604
The humidity sensitivity of a single β‐Ga2O3/amorphous SnO2 core/shell microribbon on a flexible substrate is enhanced by the application of tensile strain and increases linearly with the strain. The strain‐induced enhancement originates from the increase in the effective surface area where water molecules are adsorbed. This strain dependence of humidity sensitivity can be used to monitor the external strain. The strain sensing of the microribbon device under various amounts of mechanical loading shows excellent reliability and reproducibility with a gauge factor of ?41. The flexible device has high potential to detect both humidity and strain at room temperature. These findings and the mechanism involved are expected to pave the way for new flexible strain and multifunctional sensors. 相似文献
67.
68.
Thin films of microcrystalline (CnH2n + 1NH3)2PbBr4 (n = 4, 5, 7 and 12) have been prepared by a modified spin-coating method, and the effect of the number of carbon atoms of the alkyl chain length (n) on optical properties has been investigated. Absorption spectra reveal that (CnH2n + 1NH3)2PbBr4 films show stable excitons with a binding energy of a few hundred meV. The excitonic structure of (CnH2n + 1NH3)2PbBr4 varies with the number of carbon atoms. The lowest-energy exciton splits into a few fine-structure levels at low temperature. (CnH2n + 1NH3)2PbBr4 films (n = 5, 7 and 12) show not only singlet excitons but also triplet excitons at low temperature, while (C4H9NH3)2PbBr4 films show only singlet excitons. The intersystem crossing from excited singlet state to triplet state plays an important role in the relaxation process of excitons. 相似文献
69.
Hiroshi Abe Yusuke Imai Takefumi Goto Yukihiro Yoshimura Masami Aono Takahiro Takekiyo Hitoshi Matsumoto Takashi Arai 《Metallurgical and Materials Transactions A》2010,41(5):1137-1143
Crystal structures of room-temperature ionic liquid (RTIL)-H2O mixtures are determined by the X-ray diffraction method. The RTIL is N,N-diethyl-N-methyl-N-2-methoxyethyl ammonium tetrafluoroborate, [DEME][BF4]. At 0.9 mol pct H2O, two kinds of superstructures occur simultaneously without a strain. Also, the volume of the unit cell is very small only
at 0.9 mol pct additives. This relates to the composite domain structure, including a twin-related one, as an elastic anomaly.
At other water concentrations, such an extraordinary behavior is not observable. By assuming a sublattice having an equivalent
lattice constant, a water network at 1 mol pct H2O is simulated using a Monte Carlo (MC) method. The network develops over the medium range in the simulation box. 相似文献
70.
By using digital image correlation, the deformation behaviors of local domains of F82H joint specimens welded using tungsten inert gas (TIG) and electron beam (EB) welding were evaluated during tensile and fatigue testing. In the tensile test specimens, the tensile strength decreased in the TIG-welded joints, and ductility decreased in both the EB- and TIG-welded joints. Because axial strain increased in the tempered heat-affected zone (HAZ) and led to the fracture of the TIG-welded joint, the strength was considered to have decreased because of welding. In fatigue testing, the number of cycles to fracture for the welded joint decreased to less than 40–60% of that for the base metal. For both fracture specimens, the largest value of shear strain was observed in the region approximately between the fine-grained HAZ and tempered HAZ; this shear strain ultimately led to fracture. Cavities and macrocracks were observed in the fine-grained HAZ and tempered HAZ in the cross sections of the fracture specimens, and geometrical damage possibly resulted in the reduction of fatigue lifetime. 相似文献