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971.
Imogen S. Parry Dr. Aras Kartouzian Dr. Suzanne M. Hamilton Dr. O. Petru Balaj Prof. Dr. Martin K. Beyer Prof. Stuart R. Mackenzie 《Angewandte Chemie (International ed. in English)》2015,54(4):1357-1360
We report the observation of chemical reactions in gas‐phase Rhn(N2O)m+ complexes driven by absorption of blackbody radiation. The experiments are performed under collision‐free conditions in a Fourier transform ion cyclotron resonance mass spectrometer. Mid‐infrared absorption by the molecularly adsorbed N2O moieties promotes a small fraction of the cluster distribution sufficiently to drive the N2O decomposition reaction, leading to the production of cluster oxides and the release of molecular nitrogen. N2O decomposition competes with molecular desorption and the branching ratios for the two processes show marked size effects, reflecting variations in the relative barriers. The rate of decay is shown to scale approximately linearly with the number of infrared chromophores. The experimental findings are interpreted in terms of calculated infrared absorption rates assuming a sudden‐death limit. 相似文献
972.
Elizabeth A. German Jonathan E. Ross Dr. Peter C. Knipe Michaela F. Don Dr. Sam Thompson Prof. Dr. Andrew D. Hamilton 《Angewandte Chemie (International ed. in English)》2015,54(9):2649-2652
Many therapeutically relevant protein–protein interactions contain hot‐spot regions on secondary structural elements, which contribute disproportionately to binding enthalpy. Mimicry of such α‐helical regions has met with considerable success, however the analogous approach for the β‐strand has received less attention. Presented herein is a foldamer for strand mimicry in which dipolar repulsion is a central determinant of conformation. Computation as well as solution‐ and solid‐phase data are consistent with an ensemble weighted almost exclusively in favor of the desired conformation. 相似文献
973.
K B Cunningham M F Hamilton A P Brysev L M Krutyansky 《The Journal of the Acoustical Society of America》2001,109(6):2668-2674
Numerical simulations based on the nonlinear parabolic wave equation are used to investigate time reversal of sound beams radiated by unfocused and focused sources. Emphasis is placed on nonlinear propagation distortion in the time-reversed beam, and specifically its effect on field reconstruction. Distortion of this kind, due to amplification during time reversal, has been observed in recent experiments [A. P. Brysev et al., Acoust. Phys. 44, 641-650 (1998)]. Effects of diffraction introduced by time-reversal mirrors with finite apertures are also considered. It is shown that even in the presence of shock formation, the ability of time reversal to retarget most of the energy on the source or focal region of the incident beam is quite robust. 相似文献
974.
D. N. Poenaru B. Dobrescu W. Greiner J. H. Hamilton A. V. Ramayya 《Acta Physica Hungarica A》2001,13(1-3):79-88
A three-center phenomenological model, able to explain qualitatively the recently obtained experimental results concerning the quasimolecu-lar stage of a light-particle accompanied fission process is presented. It was derived from the liquid drop model under the assumption that the aligned configuration, with the emitted particle between the light and heavy fragment, is reached by increasing continuously the separation distance, while the radii of the heavy fragment and of the light particle are kept constant. In such a way, a new minimum appears in the deformation energy at a separation distance very close to the touching point. This minimum allows the existence of a short-lived quasi-molecular state, decaying into the three final fragments. The influence of the shell effects is discussed. The half-lives of some quasimolecular states which could be formed in the 10Be and 12C accompanied fission of 252Cf are roughly estimated to be of the order of 1 ns and 1 ms, respectively. 相似文献
975.
V. Trtík A. Pérez J. Navarro C. Ferrater F. Sánchez M. Varela 《Applied Physics A: Materials Science & Processing》1999,69(7):S815-S818
High-quality epitaxial CeO2 thin films were obtained on Si(001) buffered with a yttria-stabilised zirconia layer by pulsed laser deposition. Although the best structural properties were achieved at high substrate temperature, high-quality epitaxy was obtained even at room temperature. Epitaxial growth at low temperature is promoted by the high kinetic energy of particles reaching the substrate. The oxygen pressure and target-substrate distance had a strong influence on the crystallographic structure and surface morphology in low-temperature deposition. This behaviour is attributed to a change in the kinetic energy of the particles, which was evaluated from the plasma expansion velocity determined by an intensified CCD camera. If a shock wave forms, a minimum substrate temperature of 550 °C is necessary for epitaxial growth. 相似文献
976.
M.萨哈伊 朱胜江 甘翠云 朱凌燕 杨利明 许瑞清 全明吉 姜卓 张征 J.H.Hamilton A.V.Ramayya B.R.S.Babu J.K.Hwang W.C.Ma J.Komicki J.D.Cole R.Aryaeinejad M.W.Dirgert J.O.Rasmussen M.A 《中国物理 C》2000,24(11):1018-1023
通过对252Cf自发裂变产生的瞬发γ谱的测量,对丰中子奇A核145,147Ce的高自旋态进行了研究,首次识别了145Ce的集体带结构,扩展了147Ce的集体带结构,扩展了147Ce的能级,并新识别了3个边带,粒子–转子模型的计算指出,145,147Ce的晕带可能来自于νi13/2轨道的耦合,145Ce基态起源于(νh9/2νf7/2)组态混合,而147Ce基态则起源于νh9/2轨道.在这两个核中未观测到明显的八极形变带,然而,在147Ce中观测到的一个边带,可能显露出八极关联的迹象. 相似文献
977.
M. Pérez-Rodríguez L. M. Varela P. Taboada D. Attwood V. Mosquera 《Colloid and polymer science》2000,278(7):706-709
The association characteristics of the weakly associating drug chlorpromazine hydrochloride have been examined over the temperature
range 10–35 °C by means of conductimetric measurements. Critical micelle concentrations (cmc) have been determined by the
application of a recently developed numerical method [Pérez-Rodríguez et al. (1998) Langmuir 14:4422] especially designed for the analysis of the association pattern in highly polydisperse systems of low aggregation
number. The cmcs determined in this manner are used in combination with the mass-action model to obtain the thermodynamic
parameters of the micellisation process, in particular the surface and hydrophobic contributions to the free energy. The use
of exact forms of equations for the thermodynamics of micellisation applicable to systems of low aggregation number leads
to values of the enthalpy of micellisation in reasonable agreement with experimentally determined values.
Received: 6 January 2000/Accepted: 9 February 2000 相似文献
978.
979.
Clare M. McArdle James G. Hamilton Edwina E. Law John J. Rooney 《Macromolecular rapid communications》1995,16(10):703-712
Ring-opening metathesis polymerization has been used to prepare a series of water soluble polymers based on the Diels-Alder adducts of furan and cyclopentadiene. Hydrophobically modified forms of these polymers were obtained either by copolymerization with 5-decylbicyclo[2.2.1]hept-2-ene, post-polymerization modification of the acid forms of the polymers with 1-decylamine or chain transfer to 1-hexadecene. Polymers were characterized by NMR specroscopy and viscometry. 相似文献
980.
Erkang Fan Ji Yang Steven J. Geib Cristina Vicent Fernando Garcia-Tellado Paolo Tecilla Andrew D. Hamilton 《Macromolecular Symposia》1994,77(1):209-217
A series of hydrogen-bonding monomers has been constructed and shown to form discrete aggregates both in solution and in the solid state. 相似文献