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121.
Currently, there is an increasing interest in and demand for training in a wide variety of nonclassical music--contemporary commercial music (CCM)--and most particularly for music theater. A survey of singing teachers was completed to elucidate their training, education, and experience with and methods of teaching CCM. Teachers were at colleges, universities, and conservatories as well as in private studios, both nationally and in several foreign countries. A substantial percentage of those teaching CCM had neither formal education in teaching it nor professional experience. Many of the respondents indicated conflict between classical and CCM styles. Respondents were generally familiar with voice science and voice medicine as well as certain CCM terminology. Teachers expressed an interest in obtaining more information, with an emphasis on healthy vocal production. These results are discussed, as well as implications for the singing teacher who desires specific training to teach CCM. 相似文献
122.
Diego M. Monzn Juan Manuel Betancort Toms Martín Miguel ngel Ramírez Víctor S. Martín David Díaz Díaz 《Molecules (Basel, Switzerland)》2021,26(6)
Cyclic products can be obtained through the intramolecular version of the Nicholas reaction, which requires having the nucleophile connected to the alkyne unit. Here, we report the synthesis of 1-oxa-3-cyclooctynes starting from commercially available (1R,3S)-camphoric acid. The strategy is based on the initial preparation of propargylic alcohols, complexation of the triple bond with Co2(CO)8, and treatment with BF3·Et2O to induce an intramolecular Nicholas reaction with the free hydroxyl group as nucleophile. Finally, oxidative deprotection of the alkyne afforded the cyclooctynes in good yields. Notably, large-sized R substituents at the chiral center connected to the O atom were oriented in such a way that steric interactions were minimized in the cyclization, allowing the formation of cyclooctynes exclusively with (R) configuration, in good agreement with theoretical predictions. Moreover, preliminary studies demonstrated that these cyclooctynes were reactive in the presence of azides yielding substituted triazoles. 相似文献
123.
L. Vernac M. Pinard E. Giacobino 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(1):125-136
We show the equivalence between an ensemble of two-level atoms driven by a squeezed vacuum field, and a harmonic oscillator
coupled to a squeezed field. We give the conditions for optimal squeezing transfer from the field to the atomic ensemble.
We show that EPR-type correlations are created between the atomic ensemble and the incoming field.
Received 23 January 2001 相似文献
124.
R. Zambrini S.M. Barnett P. Colet M. San Miguel 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(3):461-471
We employ the Q-representation to study the non-classical correlations that are present from below to above-threshold in the degenerate optical
parametric oscillator. Our study shows that such correlations are present just above threshold, in the regime in which stripe
patterns are formed, but that they also persist further above threshold in the presence of spatially disordered structures.
Received: 13 September 2002 / Received in final form: 11 November 2002 Published online 28 January 2003 相似文献
125.
The determining equations for the nonclassical reductions of the heat and Burgers' equations are considered. It is shown that both systems belong to a Burgers' equation hierarchy. Each system is written in terms of the same matrix Burgers' equation that is linearized via a matrix Hopf–Cole transformation. In essence, it is shown that both systems can be solved simultaneously. Their respective solutions are then presented in a very compact form. 相似文献
126.
Shor and Preskill's and Mayers's security proof for the BB84 quantum key distribution protocol 总被引:1,自引:0,他引:1
D. Mayers 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(2):161-170
We review two security proofs for the BB84 quantum key distribution protocol: Mayers's security proof and the more recent
proof of Shor and Preskill. We focus on the basic principles and the intuition in Mayers's proof instead of technical details.
We present a variation on Shor's and Preskill's proof which is convenient for purpose of comparison. We explain the connection
between these two proofs.
Received 14 July 2001 相似文献
127.
Shi-Biao Zheng Guang-Can Guo 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,1(1):105-107
We propose a method for preparing superpositions of coherent states of the motion of an ion in an anisotropic two-dimensional
trap, in which the ion is tightly bound in the y direction. In the scheme the ion is excited by two resonant laser beams with equal amplitude, propagating along the x and y directions, respectively. In the Dicke-Lamb limit, an initial coherent state of the ion motion can be converted into a superposition
of several coherent states on a circle through the laser-ion interactions and state-selective measurements on the ion.
Received: 30 May 1997 / Revised: 29 July 1997 / Accepted: 22 October 1997 相似文献
128.
Bromination of norbornene derivatives: synthesis of brominated norbornanes and norbornenes 总被引:1,自引:0,他引:1
The low and high temperature bromination of 7-bromobicyclo[2.2.1]hept-2-ene and 2,7-dibromobicyclo[2.2.1]hept-2-ene were studied and the possible role of a neighboring group participation in rearrangements was investigated. The formation mechanism of the isomers as well as the role of the substituent on the rearrangement were discussed. The structure elucidation of the formed compounds was achieved by NMR spectral data; particularly, the γ-gauche effect was discussed in connection with the configuration of the bromine atoms. 相似文献
129.
F. Grosshans P. Grangier 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(1):119-125
Homodyne detection can be used to perform measurements on various quantum states of the light, such as conditional single
photon states produced by parametric fluorescence processes. In the pulsed regime, the time and frequency overlap between
the single photon wave packet and the local oscillator field plays a crucial role. We show in this paper that this overlap
can be characterized by an effective quantum efficiency, which is explicitly calculated in various situations of experimental
interest.
Received 27 July 2000 and Received in final form 29 November 2000 相似文献
130.
Zhao-xian Yu Zhi-yong Jiao 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,20(2):277-280
We have studied quantum effects in the interaction of the exciton with a leaky quasi-mode cavity field. When the exciton is
initially prepared in a superposition state which exhibits holes in its photon-number distribution, whereas the cavity field
initially is in the vacuum state, it is found that there exists an energy exchange between the exciton and the cavity field.
The exciton and the cavity field may exhibit sub-Poissonian distributions and quadrature squeezings. It is shown that there
does not exist a violation of the Cauchy-Schwartz inequality, which means that the correlation between the exciton and the
cavity field is classical.
Received 25 November 2000 and Received in final form 1st January 2001 相似文献