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91.
R. S. Chen Z. B. Ye Edward K. N. Yung K. F. Tsang 《International Journal of Infrared and Millimeter Waves》2003,24(8):1325-1339
A gradient optimization technique along with a definition of cost function is applied to the CAD of the circulator with a magnetized ferrite sphere for millimeter wave communications. A three-dimensional Finite-Difference Time-Domain (FDTD) approach for the analysis of this ferrite sphere based microstrip circulator is presented. The topology of the structure is enforced at each step of optimization and its physical dimensions are used as optimization variables. The cost function is defined using location of zeros and poles of the circulator's transmission, isolation, and reflection functions. Numerical tests show that the optimization process converges from an arbitrarily selected starting point with the new definition of the cost function. 相似文献
92.
Chun‐Guey Wu Hung‐Chieh Lu Liang‐Nien Chen Yung‐Chou Lin 《Journal of polymer science. Part A, Polymer chemistry》2008,46(5):1586-1597
Two new 1,10‐phenanthroline (Phen) containing conjugated oligomers, oligo‐3,8‐bis(4‐octylthiophene‐2‐yl)‐1,10‐phenanthroline) (PDTPh) and oligo‐3,8‐bis‐(4‐octyl‐5‐(4‐ctylthiophene‐2‐yl)thiophene‐2‐yl)‐1,10‐phenanthroline) (PTTPh), as well as their corresponding monomers (OTPhOT and OTOTPhOTOT) were prepared and their metal ion‐sensing properties were investigated. The oligomers showed high thermal stability, good proccessibility, and gave varied color when reacted with different metal ions. Oligomers also showed distinct responses toward metal ions when compared with their corresponding monomers, suggesting that the ionochromic responses were determined by not only the coordinating ability of Phen unit but also the conformation of oligomer chains. Moreover, the differences in the ion‐sensing behaviors between OTPhOT and OTOTPhOTOT also suggested that the coordination ability of Phen depends on its substituents. The oligo‐alkylthiophene moieties in PDTPh and PTTPh acted as spacers to reorganize the conformation of the oligomer chains, as well as the electron donating groups to adjust the coordination ability of the Phen. These findings provide a clue for designing Phen‐containing ion‐sensors for specified ion‐sensing applications. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1586–1597, 2008 相似文献
93.
Dung-Shing Hung Chen S. Tsai Chin-Chung Yu Yung Liou Shang-Fan Lee Po-Chieh Chiang Chih-Sung Ho Yeong-Der Yao 《Journal of magnetism and magnetic materials》2006
In this study, Fe/Ag/Fe/Ag ferromagnetic structures were epitaxially grown on a GaAs(1 0 0) substrate. Using the Network Analyzer (Agilent 8510C), FMR (ferromagnetic resonant) signals were observed in samples as the in-plane magnetic field was applied to either hard- or easy-axes. Of interest was that our sample demonstrated a FMR-switching behavior in hard-axis but not in easy-axis. The detecting data showed that the switch magnetic field was much smaller than what has been stated previously in Fe/Cu/Fe systems by other laboratories. In addition to the frequency switch in FMR, we also observed a magnetic reversal behavior in its M–H curve. Data presented that both of the FMR and magnetic reverse took place in the same direction (hard-axis). 相似文献
94.
95.
96.
R. S. Chen D. X. Wang Edward K. N. Yung 《International Journal of Infrared and Millimeter Waves》2003,24(8):1307-1323
The boundary marching method is applied for the analysis of the waveguide bandpass filers. The vector finite element method with the perfectly matched layers (PML) as the matching load is given for parameter extraction of millimeter wave filters. The implementation of the fast boundary marching method is described in detail. The reflection and insertion losses of millimeter wave filters are obtained and compared with those obtained from literature. 相似文献
97.
Dung Yung Yan 《Proceedings of the American Mathematical Society》1996,124(6):1913-1915
Using the Snaith-Mitchell-Priddy splittings of and , we can give new stable splittings of and
respectively.
respectively.
98.
Krumper JR Martin RL Hay PJ Yung CM Veltheer J Bergman RG 《Journal of the American Chemical Society》2004,126(45):14804-14815
Protonolysis of the dimethylrhenium(III) compound Cp(PMe(3))(2)Re(CH(3))(2) (3) led to formation of the highly reactive hydridorhenium methylidene compound [Cp(PMe(3))(2)Re(CH(2))(H)][OTf] (4), which was characterized spectroscopically at low temperature. Although 4 decomposed above -30 degrees C, reactivity studies performed at low temperature indicated it was in equilibrium with the coordinatively unsaturated methylrhenium complex [Cp(PMe(3))(2)Re(CH(3))][OTf] (2). Methylidene complex 4 was found to react with PMe(3) to afford [Cp(PMe(3))(3)Re(CH(3))][OTf] (6) and with chloride anion to give Cp(PMe(3))(2)Re(Me)Cl (7). When BAr(f) anion was added to 4, the thermally stable methylrhenium methylidene complex [Cp(PMe(3))(2)Re(CH(2))(CH(3))][BAr(f)] (8) was isolated upon warming to room temperature. The mechanisms of formation of both 4 and 8 are discussed in detail, including DFT calculations. The novel carbonyl ligated complex Cp(CO)(2)Re(CH(3))OTf (12) was prepared, isolated, and found to not undergo migration reactions to form methylidene complexes. 相似文献
99.
Os and Os–Pd nanoparticles supported on multi-walled carbon nanotubes were prepared by vacuum pyrolysis at 573 K using the
[Os3CO10(NCMe)2] and [Pd(acac)2] as precursors. The nanoparticles prepared showed a narrow size distribution (Os: 1.8 nm; Os–Pd: 4.3 nm) and were decorated
evenly on the surface of the nanotubes. By controlling the metal-to-nanotube ratio, Os nanotubes were prepared using the carbon
nanotubes as a template. The catalysis of Os–Pd nanoparticles towards CVD carbon nanotube synthesis was studied.
Dedicated to Professor Gunther Schmid on the occasion of his 70th birthday. 相似文献
100.
The equilibrium dynamics of the acetyl and amino amide-I groups of the alanine dipeptide were examined separately using (13)C isotopic selection and 2D IR. The population relaxation times of the amide transitions were measured to be in the range 500 fs by means of heterodyne transient grating methods. The vibrational frequency correlation functions consisted in all cases of a motionally narrowed part, a component near 800 fs, and a constant part representing a distribution of structures that is static on the few ps time scale. The intermediate time scale is attributed to fluctuations in the stretching and bending of hydrogen bonds between the carbonyl and water. 相似文献