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排序方式: 共有10000条查询结果,搜索用时 46 毫秒
981.
Y.T. Chen S.U. Jen Y.D. Yao J.M. Wu G.H. Hwang T.L. Tsai Y.C. Chang A.C. Sun 《Journal of magnetism and magnetic materials》2006
Co50Fe50 films with thickness varying from 100 to 500 Å were deposited on a glass substrate by sputtering process, respectively. Two kinds of CoFe films were studied: one was the as-deposited film, and the other the annealed film. The annealing procedure was to keep the films at 400 °C for 5 h in a vacuum of 5×10−6 mbar. From the X-ray study, we find that the as-deposited film prefers the CoFe(1 1 0) orientation. Moreover, the body-centered cubic (bcc) CoFe(1 1 0) line is split into two peaks: one corresponding to the ordered body-centered tetragonal (bct) phase, and the other, the disordered bcc phase. After annealing, the peak intensity of the ordered bct phase becomes much stronger, while that of the disordered bcc phase disappears. The annealing has also caused the ordered CoFe(2 0 0) line to appear. When the amount of the ordered bct phase in Co50Fe50 is increased, the saturation magnetization (Ms) and coercivity (Hc) become larger, but the electrical resistivity (ρ) decreases. From the temperature coefficient of resistance (TCR) measurement, we learn that the bct grains in the CoFe film start to grow at temperature 82 °C. 相似文献
982.
S. C. Tiwari 《Foundations of Physics Letters》2006,19(1):51-62
Advances in gauge theories and unified theories have not thrown light on the meaning of electron. The problem of the origin
of electronic charge is made precise, new insights gained from Weyl space are summarized, and the origin of charge in terms
of fractional spin is suggested. A new perspective on the abelian Chern-Simons theory is presented to explain charge. 相似文献
983.
S. O. Olabanji O. R. Omobuwajo D. Ceccato M. C. Buoso M. De Poli G. Moschini 《Journal of Radioanalytical and Nuclear Chemistry》2006,270(3):515-521
Summary Analysis of thirteen medicinal plants of various biological activities commonly used in South-western Nigeria was carried
out using PIXE technique. Nine of these plants are anti-cancer while four are antimicrobial. PIXE measurements were carried
out using collimated proton beams delivered by the 2. 5 MV AN 2000 Van de Graaff accelerator at the Istituto Nazionale di
Fisica Nucleare (INFN), (LNL) Legnaro, (Padova), Italy. The results showed the presence of twenty three different elements
in the plants and none of them contains any toxic heavy metals. Only Chenopodium ambrosioides showed detectable levels of selenium which is considered important in cancer prevention. 相似文献
984.
985.
The synthesis of the title compounds has been achieved in concise, highly regiocontrolled fashion from commercially available (+)-sclareolide. In addition, we offer evidence that the structure of a newly reported natural product from Zingiber ottensii is incorrect. 相似文献
986.
Wally L. Chang Kurt C. Frisch Kaneyoshi Ashida 《Journal of polymer science. Part A, Polymer chemistry》1989,27(11):3637-3649
The anionic polymerization of ?-caprolactam (CLM) has been shown to proceed at high reaction rate when catalyzed by metallic lactamates and initiated by acyllactams. The role of initiator and catalyst concentration on the process of ?-caprolactam anionic polymerization has been explored, with the aim of selecting the most suitable experimental conditions for reaction injection molding (RIM). The overall polymerization rates and physical properties for reaction injection molding of star-shaped nylon 6 homopolymer have been studied by the quasi-adiabatic process. In order to model the actual rapid molding conditions, time vs. temperature reaction profiles were measured, and the relative rates of polymerization subsequently determined from these data. 相似文献
987.
G. Lazarides C. Panagiotakopoulos Q. Shafi 《Zeitschrift fur Physik C Particles and Fields》1987,34(4):553-554
We discuss gauge models based on a superstring motivated rank six subgroup ofE 6. Lepton number is an accidental unbroken symmetry of the models which leads to an essentially stable proton. One of the neutral gauge bosons couples toB-L and may have mass below a TeV. 相似文献
988.
X.C. Li J. Wu K. Xu A.Q. Liu J.T. Lin 《Applied Physics A: Materials Science & Processing》2007,89(2):327-332
This paper presents the theoretical model and the optimization method to suppress the sidelobes of side-coupled photonic crystal
filters. Numerical verification shows a good agreement between the theoretical method and the finite-difference time-domain
simulation, but the theoretic method does not involve the time-consuming computation. The theoretical method also presents
a better physical image for choosing the critical parameters, such as the quality factor, phase shift and the number of resonators.
Based on the theoretical model, two optimization methods (chirp and cascading) are proposed to deeply suppress the sidelobes.
They also show more flexibility in controlling the bandwidth and steepness of the roll-off in the filter.
PACS 42.70.Qs 相似文献
989.
In this paper we develop the fundamental elements and results of a new theory of regular functions of one quaternionic variable. The theory we describe follows a classical idea of Cullen, but we use a more geometric formulation to show that it is possible to build a rather complete theory. Our theory allows us to extend some important results for polynomials in the quaternionic variable to the case of power series. 相似文献
990.
We define the Sheffer group of all Sheffer-type polynomials and prove the isomorphism between the Sheffer group and the Riordan group. An equivalence of the Riordan array pair and generalized Stirling number pair is also presented. Finally, we discuss a higher dimensional extension of Riordan array pairs. 相似文献