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排序方式: 共有618条查询结果,搜索用时 15 毫秒
1.
A skew of a paper transferred by rubber rollers in printers is simulated by FEM software. Effects of an imbalance of preload, an imbalance distribution of coefficient of friction and a front tension on the paper skew are investigated and how to determine the skew direction are shown. A simulation model is composed of a feed roller, a preload roller and a paper. The feed roller is rotated forcibly by a certain degree at every calculation step and a deformation, displacement and strain of the paper and rollers are calculated. A series of calculation results is shown as a motion simulation. The results show that the paper skews to the smaller preload side, to the smaller coefficient of friction side, or to the opposite side of the front tension. Further, effects of a skew prevention guide plate is simulated. 相似文献
2.
A novel current source inverter system interconnected to the single‐phase grid is proposed. It has the same construction as the conventional three‐phase current source inverter that is interconnected to the single‐phase three‐wire distribution system. Though the proposed circuit has no output transformer, it can be equivalently performed as the single‐phase double cascade inverter by diverting the pole transformer in the utility system. By controlling the appropriate scheme, the output currents can be obtained as the five‐level waveforms and their distortions can be decreased sufficiently. It is applied to the interactive electric energy storage system with batteries and the basic discharging characteristics are discussed experimentally. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(2): 50–61, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10380 相似文献
3.
The statistical properties of decaying compressible turbulence are investigated by direct numerical simulations of flow in a periodic cube. Starting with fully developed turbulence for various microscale Reynolds numbersR
, rms Mach numbersM, and small- and large-scale compressive ratiosr
CS
andr
CL
, we find that the kinetic energy exhibits an exponential decay in time. Interactions between the compressive and rotational components of kinetic energy are weaker than self-interactions of the respective components. The energy spectrum of rotational component obeys the same Kolmogorov similarity law as for incompressible turbulence and forced compressible turbulence. The form of the energy spectrum of the compressive component, on the other hand, depends strongly onM. As the turbulence decays freely,R
andM decrease in time butr
CS andr
CL tend to some universal values. 相似文献
4.
Hisao Ichijo Tetsuro Suehiro Aizo Yamauchi Shigeo Ogawa Masanori Sakurai Nobuo Fujii 《应用聚合物科学杂志》1982,27(5):1665-1674
A poly(vinyl alcohol) (PVA) fiber support incorporating various aminoacetal functional groups has been developed for immobilizing enzymes. The aminated PVA fiber seems to adsorb enzymes with electrostatic force of attraction; thus the immobilization procedure is simple. By the use of this fiber having immobilized enzymes, the reaction between enzymes and substrates is nearly independent of the size of subtstrates. This newly developed type of fiber, which is formed by a mass superfine fibers (SFF), each measuring 1 μm or less in diameter, permits much more increased surface area than the conventional enzyme immobilization supports. Our studies of the properties of the fiber for immobilization of enzymes show the following results: (1) SFF has a greater ability for the immobilization of invertase than ordinary fibers; (2) dimethyl-aminated SFF has the best performance for the immobilization of invertase. From these results, it is concluded that the dimethyl-aminated SFF is an excellent support for the immobilization of invertase. 相似文献
5.
Styrene was grafted onto cellulose acetate p-nitrobenzoate (CANB) by chain transfer reaction of growing polymer radicals to the pendant nitro groups of CANB. A copolymer with a branch for every 17.2 nitro groups was obtained. This result indicates that the pendant aromatic nitro group is more effective in obtaining a graft copolymer by radical mechanism than pendant double bond on the trunk polymer previously reported, where graft copolymers with a branch for several hundred of double bonds are produced. 相似文献
6.
Lida T Nakamori R Yabuta R Yada S Takagi Y Mano N Ikegawa S Goto J Nambara T 《Lipids》2002,37(1):101-110
A facile and efficient synthesis of the carboxyl-linked glucosides of bile acids is described. Direct esterification of unprotected
bile acids with 2,3,4,6-tetra-O-benzyl-d-glucopyranose in pyridine in the presence of 2-chloro-1,3,5-trinitrobenzene as a coupling agent afforded a mixture of the
α- and β-anomers (ca. 1∶3) of the 1-O-acyl-d-glucoside benzyl ethers of bile acids, which was separated effectively on a C18 reversedphase chromatography column (isolated yields of α- and β-anomers are 4–9% and 12–19%, respectively). Subsequent hydrogenolysis
of the α- and β-acyl glucoside benzyl ethers on a 10% Pd−C catalyst in acetic acid/methanol/EtOAc (1∶2∶2, by vol) at 35°C
under atmospheric pressure gave the corresponding free esters in good yields (79–89%). Chemical specificities such as facile
hydrolysis and transesterification of the acyl glucosides in various solvents were also discussed. 相似文献
7.
The effect of the reaction kinetics on the ionic conductivity for a comblike‐type polyether (MEO) electrolyte with lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) was characterized by DSC, complex impedance measurements, and 1H pulse NMR spectroscopy. The ionic conductivity of these electrolytes was affected by the reaction condition of the methacrylate monomer and revealed by the glass transition temperature (Tg), spin–spin relaxation time (T2), steric effects of the terminal groups, and the number of charge carriers indicated by the VTF kinetic parameter. In this system, the electrolytes prepared by the reaction heating rate of 10°C/min of MEO–H and 15°C/min of MEO–CH3 showed maximum ionic conductivity, σi, two to three times higher in magnitude than that of the σi of the others at room temperature. As experimental results, the reaction kinetic rate affected the degree of conversion, the ionic conductivity, and the relaxation behaviors of polyether electrolytes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2149–2156, 2003 相似文献
8.
Y. Nakama Y. Shiojima Y. Takeshita M. Yamaguchi 《Journal of the American Oil Chemists' Society》1997,74(7):803-808
The formation of a complex, composed of lauroamphoglycinate (LG), oleic acid (OA) and water, was investigated, and this system
was applied to emulsification. The complex was formed in the water-rich area (more than 90% in this system) at a molar ratio
of OA to LG from 1 to 3, where two-phase systems of water and the complex existed. The interaction between LG and OA, both
in the aqueous solution and at the interface of liquid paraffin dissolving the OA and LG solution, was studied by pH measurements
and interfacial tension measurements, respectively. The results implied that LG and OA were linked stoichiometrically, both
in aqueous solution and at the interface, and formed complexes. X-ray diffraction patterns and the strong hydrophobicity showed
that the equimolar complex composed of LG, OA, and water was a liquid crystal with a reversed hexagonal structure. The reversed
hexagonal liquid crystal was capable of solubilizing a certain amount of liquid paraffin in its alkyl group parts while maintaining
its hexagonal structure. These results suggest the possibility to prepare a W/O-type emulsion by using the liquid crystal
formed by LG, OA, partial liquid paraffin, and water as the continuous phase. The authors could obtain a stable W/O emulsion
without coalescence of the water droplets that contained a substantial amount of water (approximately 90%). Furthermore, various
types of emulsions, O/W, W/O, W/O/W, could be prepared by changing the ratio of LG and OA. 相似文献
9.
O Nureki DG Vassylyev M Tateno A Shimada T Nakama S Fukai M Konno TL Hendrickson P Schimmel S Yokoyama 《Canadian Metallurgical Quarterly》1998,280(5363):578-582
High-fidelity transfers of genetic information in the central dogma can be achieved by a reaction called editing. The crystal structure of an enzyme with editing activity in translation is presented here at 2.5 angstroms resolution. The enzyme, isoleucyl-transfer RNA synthetase, activates not only the cognate substrate L-isoleucine but also the minimally distinct L-valine in the first, aminoacylation step. Then, in a second, "editing" step, the synthetase itself rapidly hydrolyzes only the valylated products. For this two-step substrate selection, a "double-sieve" mechanism has already been proposed. The present crystal structures of the synthetase in complexes with L-isoleucine and L-valine demonstrate that the first sieve is on the aminoacylation domain containing the Rossmann fold, whereas the second, editing sieve exists on a globular beta-barrel domain that protrudes from the aminoacylation domain. 相似文献
10.
Yang Yang Shigeo Hirose Paulo Debenest Michele Guarnieri Norimitsu Izumi Koichi Suzumori 《Advanced Robotics》2016,30(21):1415-1429
To avert potential crisis from Japan’s aging infrastructure and declining birth rate, the Japanese Government is planning to introduce robotic technology for the inspection of social infrastructure (such as pipes, dams, and bridges). Recording underwater positions is a difficult task for human divers who undertake conventional dam inspections. This study presents the Anchor Diver 5.2 system for efficient and effectual dam inspection. Anchor Diver 5.2 is based on an extended-tether-maneuvered remotely operated vehicle (ROV) equipped with cameras. The ROV is lowered into water by a hoist system from a boat and implements a visual survey of the concrete underwater structure. To improve the visibility of the ROV in murky and cloudy water, a novel concept named Water Loupe is proposed. In addition, a simple boat-fixing method is proposed to provide a stable base on the water surface, and the underwater position of the ROV, which cannot be accessed by global positioning systems, is recorded using a feasible localization method. Finally, the developed system was evaluated in field experiments conducted in the Amagase Dam, Japan, and its merits and problems are discussed. 相似文献