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451.
本文中,我们对茅德康在【D.K.Mao,Towards front-tracking based on conservation in two space dimensionsⅡ,tracking discontinuities in capturing fashion,J.Comput.Phys.,226,(2007),pp 1550-1588】一文中所建立的守恒型跟踪法进行了改进,成功将算法运用到多介质流体界面的计算中.最后,我们使用改进后的算法计算了两个数值算例,验证了算法的有效性. 相似文献
452.
We apply the technique of the Green's function to the vibronically tangled spectrum of pyrene in a biphenyl matrix. We can deperturb the spectrum mathematically and readily assign the resulting weighted density of states. The analysis is reasonably successful and agrees with ground-state data and estimates of the excited-state frequencies previously made by others. 相似文献
453.
454.
The results of experimental and theoretical investigations on the mechanism of competitive [3+2] versus [4+2] cycloaddition reactions of simple acyclic imines with nitrosoalkenes are reported. The effect of substituents on the iminic nitrogen in influencing the cycloaddition pathways has been meticulously explored. 相似文献
455.
Tehseen Aman Shamma Firdous Islam Ullah Khan Asrar Ahmad Kazi 《Mikrochimica acta》2001,137(3-4):121-126
Phenytoin sodium reacts with o-nitrobenzoic acid in alkaline media after heating for 10 minutes at 70 °C, to give a red coloured
complex having maximum absorbance at 510 nm. The reaction is selective for phenytoin sodium with 0.01 mg/10 mL as visual limit
of quantitation and provides a basis for a new spectrophotometric determination. The colour reaction obeys Beer’s law from
0.01 mg to 3 mg/10 mL of phenytoin sodium and the relative standard deviation is 0.29%. The quantitative assessment of tolerable
amounts of other drugs is also studied.
Received May 2, 2000. Revision May 11, 2001. 相似文献
456.
Brian Herman Pawel Wodnicki Seongwook Kwon Ammasi Periasamy Gerald W. Gordon Nupam Mahajan Xue Feng Wang 《Journal of fluorescence》1997,7(1):85-91
Time-resolved fluorescence lifetime microscopy (TRFLM) allows the combination of the sensitivity of fluorescence lifetime
to environmental parameters to be monitored in a spatial manner in single living cells, as well as providing more accurate,
sensitive, and specific diagnosis of certain clinical diseases and chemical analyses. Here we discuss two applications of
TRFLM: (1) the use of nonratiometric probes such as Calcium Crimson, for measuring Ca2+; and (2) quantification of protein interaction in living cells using green and blue fluorescent protein (GFP and BFP, respectively)
expressing constructs in combination with fluorescence resonance energy transfer microscopy (FRET). With respect to measuring
Ca2+ in biological samples, we demonstrate thatintensity-based measurements of Ca2+ with single-wavelength Ca2+ probes such as Calcium Crimson may falsely report the actual Ca2+ concentration. This is due to effects of hydrophobicity of the local environment on the emission of Calcium Crimson as well
as interaction of Calcium Crimson with proteins, both of which are overcome by the use of TRFLM. The recent availability of
BFP (P4-3) and GFP (S65T) (which can serve as donor and acceptor, respectively) DNA sequences which can be attached to the
carboxy-or amino-terminal DNA sequence of specific proteins allows the dual expression and interaction of proteins conjugated
to BFP and GFP to be monitored in individual cells using FRET. Both of these applications of TRFLM are expected to enhance
substantially the information available regarding both the normal and the abnormal physiology of cells and tissues. 相似文献
457.
Infrared absorption spectra of N,N′-dimethyl formamide in the absence and presence of water, rhodamine 6G and water–rhodamine 6G mixture are reported. Assignment of observed bands has been made on the basis of density functional theory calculations and available assignments in the literature. Certain bands show changes in their positions and intensities when water is added to N,N′-dimethylformamide. This is due to hydrogen bonding interaction between these molecules. Similar changes are also observed for dimethylformamide and Rh6G mixture to a lesser extent. The presence of Rh6G in a dimethylformamide–water mixture reverses these spectral changes due to preferential solvation of Cl? by water molecules. Solvation reduces or nullifies the hydrogen bonding between dimethylformamide and water in the mixture. 相似文献
458.
459.
K. R. P. M. Rao Frank E. Huggins Vikram Mahajan Gerald P. Huffman V. U. S. Rao 《Hyperfine Interactions》1994,93(1):1745-1749
Mössbauer spectroscopy studies of iron catalysts from a Fischer-Tropsch (FT) Pilot Plant run at different time-on-stream periods were carried out. Magnetite Fe3O4 was found to be active for the water-gas-shift (WGS) reaction which accompanies the FT synthesis reaction over Fe-based catalysts. A correlation between the ratio of the occupancy of octahedral sites to the tetrahedral sites in magnetite to the WGS activity was found. Cation-deficient magnetite gave higher WGS activity as compared to the stoichiometric phase. 相似文献
460.
Ultrasonic attenuation has been measured in the intermediate state of high purity single crystals of indium of different sizes over the frequency range 10–30 MHz. Oscillations in the temperature dependence of attenuation of longitudinal ultrasound have been observed and are discussed here in the light of a recent theory. 相似文献