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51.
In this paper, we describe a three-dimensional (3D) electromagnetic (EM) approach to the modeling of active devices in their linear regime. The technique basically relies on the self-consistent introduction of distributed controlled current sources in the 3D EM simulation of passive components. The approach is validated by comparing measured and calculated results for a pseudomorphic high electron-mobility transistor in the millimeter-wave range. However, it may also be applied to a larger class of field-effect transistors, including MESFETs. 相似文献
52.
53.
I. V. Smetanin D. Farina J. Koga K. Nakajima S. V. Bulanov 《Physics letters. A》2004,320(5-6):438-445
An elliptically polarized electromagnetic wave in an underdense plasma acquires a longitudinal component of the electric field which oscillates as even harmonics of the fundamental frequency. The phase shift between transverse field components and the wave amplitudes exhibit nonlinear oscillations. 相似文献
54.
55.
Exploiting Synergistic Effects in Organozinc Chemistry for Direct Stereoselective C‐Glycosylation Reactions at Room Temperature 下载免费PDF全文
Dr. Alberto Hernán‐Gómez Dr. Samantha A. Orr Dr. Marina Uzelac Dr. Alan R. Kennedy Dr. Santiago Barroso Dr. Xavier Jusseau Dr. Sébastien Lemaire Dr. Vittorio Farina Prof. Eva Hevia 《Angewandte Chemie (International ed. in English)》2018,57(33):10630-10634
Pairing a range of bis(aryl) zinc reagents ZnAr2 with the stronger Lewis acidic [(ZnArF2)] (ArF=C6F5), enables highly stereoselective cross‐coupling between glycosyl bromides and ZnAr2 without the use of a transition metal. Reactions occur at room temperature with excellent levels of stereoselectivity, where ZnArF2 acts as a non‐coupling partner although its presence is crucial for the execution of the C(sp2)–C(sp3) bond formation process. Mechanistic studies have uncovered a unique synergistic partnership between the two zinc reagents, which circumvents the need for transition‐metal catalysis or forcing reaction conditions. Key to the success of the coupling is the avoidance of solvents that act as Lewis bases versus diarylzinc compounds (e.g. THF). 相似文献
56.
Brackmann F Schill H de Meijere A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(22):6593-6600
Protected racemic and enantiomerically pure 3,4-(aminomethano)prolines rac-9 and (2S,2'R,3R,4R)-9 have been prepared applying a titanium-mediated reductive cyclopropanation as a key step. Thus, cyclopropanations of N,N-dibenzylformamide with titanacyclopropanes generated in situ from racemic or enantiomerically pure tert-butyl N-Boc-3,4-dehydroprolinates rac-8 or (S)-8 proceed diastereoselectively, and furnish the protected racemic and enantiomerically pure diamino acid 9. The latter was incorporated into three tripeptides containing glycyl, alanyl and phenylalanyl moieties. 相似文献
57.
Luca F. Raveglia Giuseppe A. M. Giardina Mario Grugni Roberto Rigolio Carlo Farina 《Journal of heterocyclic chemistry》1997,34(2):557-559
The 3-chloro and 3-bromo-2-phenylquinoline-4-carboxylic acids were obtained in good yields through a novel procedure, entailing the synthesis of the 3-amino intermediate and the subsequent replacement of the amino group with chlorine or bromine, according to the Sandmeyer reaction. 相似文献
58.
L. Bencivenni A. Farina S.Nunziante Cesaro R. Teghil M. Spoliti 《Journal of Molecular Structure》1980
The IR and Raman spectra of gaseous and solid CH3TiX3 and CD3TiX3 species (X = Cl, Br, I) are reported. The gas phase spectra have been recorded between 4000 and 20 cm?1 at pressures of 1 atm and 4 atm at 350 K and the Raman spectra of the solid phase recorded at 4.2 K. Internal rotation barriers and thermodynamic functions have been calculated. 相似文献
59.
J. E. G. Farina 《International Journal of Theoretical Physics》1982,21(2):83-103
A rigorous discussion of the concept of expectation value of an unbounded observable is given, and of its variance. It is shown that ifA andB are observables for which the expectations <A
2> and <B
2> exist, and such that A+B is also an observable for some real numbers and , neither of which vanishes, then a quantum mechanical analog of covariance and correlation coefficient can be defined. The quadratic variation with time of the variance of position of a particle moving freely in one dimension is deduced rigorously, assuming only that there is a time at which the variances of position and momentum exist. 相似文献
60.