排序方式: 共有31条查询结果,搜索用时 500 毫秒
11.
Aptowicz KB Pan YL Chang RK Pinnick RG Hill SC Tober RL Goyal A Jeys T Bronk BV 《Optics letters》2004,29(17):1965-1967
Two-dimensional angular optical scattering (TAOS) patterns of droplets composed of a mixture of H2O and D2O are detected in the mid infrared. First, a lens is used in the Abbé sine condition to collect a small solid angle of light, where the scattering pattern matches well numerical simulations based on Mie theory. Next, TAOS patterns from droplets spanning a large (approximately 27pi sr) solid angle are captured simultaneously at two wavelengths. The effects of absorption are evident in the patterns and are discernible without the need for curve matching by Mie theory. 相似文献
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Eric?R.?Pinnick Camilo?E.?Calderon Andrew?J.?Rusnak Feng?WangEmail author 《Theoretical chemistry accounts》2012,131(3):1146
This paper studies the possibility of improving the convergence of ab initio free energy perturbation (FEP) calculations by
developing customized force fields with the adaptive force-matching (AFM) method. The ab initio FEP method relies on a molecular
mechanics (MM) potential to sample configuration space. If the Boltzmann weight of the MM sampling is close to that of the
ab initio method, the efficiency of ab initio FEP will be optimal. The difference in the Boltzmann weights can be quantified
by the relative energy difference distribution (REDD). The force field developed through AFM significantly improves the REDD
when compared with standard MM models, thus improving the convergence of the ab initio FEP calculation. The static dielectric
constant εs of ice-Ih was studied with PW-91 through ab initio FEP. With a customized force field developed through AFM, we were able
to converge εs to 80 ± 4 with 3,600 configurations. A similar ab initio FEP calculation with the TIP4P model would require 220 times more
configurations to achieve the same accuracy. Our study indicates that the PW-91 functional underestimates ice-Ih εs by about 20%. 相似文献
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Nitro compounds are converted into the corresponding carbonyl compounds by treatment with base and MoO5·Pyr·HMPA. 相似文献
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A variety of methods for the conversion of α,β-unsaturated aldehydes to the corresponding acids have been explored. The best approach uses sodium chlorite and gives the desired transformation even in systems where steric hindrance and/or sensitive functionality are present. 相似文献
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MV Muftakhov YV Vasil'ev VA Mazunov 《Rapid communications in mass spectrometry : RCM》1999,13(12):1104-1108
Appearance energies of [M-H](-) ions from carbonyl compounds R-CO-R' (R,R' = H, CH(3), NH(2), OH) have been measured by means of negative ion mass spectrometry in resonant electron capture mode. Values of electron affinity of the corresponding radicals, CH(2)&dbond;C(X)O, NH&dbond;C(X)O and O&dbond;C(X)O, have been determined. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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The melting temperature of ice-Ih was calculated with only electronic structure information as input by creating a problem-specific force field. The force field, Water model by AFM for Ice and Liquid (WAIL), was developed with the adaptive force matching (AFM) method by fitting to post-Hartree-Fock quality forces obtained in quantum mechanics∕molecular mechanics calculations. WAIL predicts the ice-Ih melting temperature to be 270 K. The model also predicts the densities of ice and water, the temperature of maximum density of water, the heat of vaporizations, and the radial distribution functions for both ice and water in good agreement with experimental measurements. The non-dissociative WAIL model is very similar to a flexible version of the popular TIP4P potential and has comparable computational cost. By customizing to problem-specific configurations with the AFM approach, the resulting model is remarkably more accurate than any variants of TIP4P for simulating ice-Ih and water in the temperature range from 253 K and 293 K under ambient pressure. 相似文献
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Fernandez-Lima FA Pinnick VT Della-Negra S Schweikert EA 《Surface and interface analysis : SIA》2011,43(1-2):53-57
First evidence of photon emission from individual impacts of massive gold projectiles on solids for a number of projectile-target combinations is reported. Photon emission from individual impacts of massive Au(n) (+q) (1 ≤ n ≤ 400; q = 1-4) projectiles with impact energies in the range of 28-136 keV occurs in less than 10 ns after the projectile impact. Experimental observations show an increase in the photon yield from individual impacts with the projectile size and velocity. Concurrently with the photon emission, electron emission from the impact area has been observed below the kinetic emission threshold and under unlikely conditions for potential electron emission. We interpret the puzzling electron emission and correlated luminescence observation as evidence of the electronic excitation resulting from the high-energy density deposited by massive cluster projectiles during the impact. 相似文献
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Guy Indebetouw 《中国光学快报(英文版)》2009,(12)
Recent developments in scanning holographic microscopy that offer the prospects of new quantitative tools and imaging modalities in bio, micro, and nano sciences are reviewed. The versatility of the method is emphasized. Scanning holography can operate in an incoherent mode for fluorescence imaging, in a coherent mode for quantitative phase imaging, or in a tomographic mode for axial sectioning and rejection of the out-of-focus haze. Possible applications are illustrated with examples, and future prospects ... 相似文献