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排序方式: 共有825条查询结果,搜索用时 31 毫秒
121.
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Yoshiaki Tsunawaki Mie Noguchi Mitsuhiro Kusaba Nobuhisa Ohigashi Masayuki Fujita Kazuo Imasaki Shin-ichiro Kuruma Kunioki Mima Sadao Nakai Chiyoe Yamanaka 《International Journal of Infrared and Millimeter Waves》1998,19(2):177-184
A hybrid planar wiggler with a period of 20 mm has been studied as the simplest one which gives the strong field including some higher harmonic components by selecting proper sizes of the ferromagnetic and the permanent magnet. Small gap length of the wiggler and small width of permendur satisfy these conditions to a certain degree.Gain analysis of FEL suggests that for high wiggler field of K>1 1.6, higher harmonic gains are improved primarily due to its strong field, and for low wiggler field of K< 1 1.6, they are mainly due to the modification of the wiggler field distribution. 相似文献
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124.
Matsumoto H Konosu Y Kimura N Minagawa M Tanioka A 《Journal of colloid and interface science》2007,309(2):272-278
Membrane potential measurement has been widely used for the characterization of ionic membranes such as ion-exchange membranes without solvent permeability. However, there have been few studies on membrane potentials across pressure-driven processes such as reverse osmosis (RO) membranes with solvent permeability. In the present study, the membrane potential across RO membranes in NaCl and MgCl2 under the pressure gradient, DeltaP=0-0.3 MPa, was measured. The experimental results were analyzed by the theoretical model based on the Donnan equilibrium and the extended Nernst-Planck flux equation considering the pressure effect. The theoretical values agreed well with the experimental ones. This indicates that membrane potential is useful for characterizing the effective charge density of the active layer of RO membranes under pressure gradient. 相似文献
125.
研究了以三氟甲基磺酸三甲基硅酯[(CH~3)~3SiOSO~2CH~3,TMSOFf]为主引发剂,TiCl~4为共引发剂的复合引发体系对1,3-戊二烯(PD)的聚合行为。TMSOTf/TiCl~4复合体系引发PD不但比单独的TiCl~4引发具有更高的引发活性,而且提高了聚合物分子量,能把聚合反应速率提高8.8倍,把聚合物的收率从TiCl~4引发的62.5%提高到95%以上。对该复合体系聚合PD的动力学,反应机理所作的研究表明:TMSOTf和TMSOTf/TiCl~4都是通过它们与体系中残存水通过水解生成的质子酸引发进行的,聚合反应属一级反应。在该体系中加入酮类后,产率和分子量均降低,但均随着酮类的位阻的增加而增大。 相似文献
126.
A condition is given for a certain generalized maximal operator to be of weak type (ps, qs), where 1≤p≤q<∞, 1≤s<∞. This operator unifies various results about the Poisson integral operators cited in the literature. 相似文献
127.
Pulsed Hot-Wire Anemometry (PHWA) measurements are performed in well defined two- and three-dimensional turbulent wall jets.
For the two-dimensional wall jet the objective is to study reported differences between conventional Hot-Wire Anemometry (HWA)
and Laser Doppler Anemometry (LDA) results. In the three dimensional wall jet, new improved data are provided, employing a
measuring technique suitable for highly turbulent flows. This, since only hot-wire results previously have been published
for this flow. The pulsed wire results show good agreement with existing Laser Doppler anemometer data in the two-dimensional
wall jet, both reporting significantly higher turbulence levels in the outer region of the flow than hot-wires do. The hot-wire
anemometer errors generally increase with increasing local turbulence intensity and since the three-dimensional wall jet has
a higher turbulence level than its two-dimensional equivalent, the new pulsed hot-wire results improve the information available
for the turbulence field in this flow significantly.
Received: 29 January 1998/ Accepted: 19 February 1999 相似文献
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129.
概括了环链转移反应的类型、机理,同时综述了环链转移反应在合成取代杂环化合物中的应用。 相似文献
130.