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排序方式: 共有131条查询结果,搜索用时 187 毫秒
1.
Chromatographic retention data and thermodynamic properties of six pine terpenes (α-pinene, β-pinene, camphene, limonene, α-phellandrene and p-cymene) on six different liquid phases, with a wide range of polarity, are reported at temperatures from 80 to 120 °C. The retention behaviour and selectivity of liquid phases for the separation of binary solute systems are discussed in terms of activity coefficients and specific interactions. Solubility parameters for the liquid phases are reported using the regular solution theory and the Takamiya equation and a good correlation between polarity and solubility parameters is observed. 相似文献
2.
Stig E. Friberg Ibrahim Kayali Tatang Suhery Linda D. Rhein F. Anthony Simion 《Journal of Dispersion Science and Technology》2013,34(3):337-347
Water uptake in natural and reaggregated stratum corneum was determined by weight difference after storage in an atmosphere of controlled relative humidity. Interlayer spacing in separated lipids as a function of their water content was determined by low-angle X-ray diffractometry. These values were used as a calibration curve to determine the water content of the lipid bilayers in reaggregated stratum corneum. The results revealed different behavior of the lipid models compared to natural lipids of the stratum corneum. The additional water taken up after reaggregation of equilibrated lipids and proteins, was equally partitioned between the protein and the natural lipid fraction, while the models gave a proportionally higher water uptake into the lipids at high relative humidity. It is obvious that the models, so far, do not mimic all the properties of the natural stratum corneum lipids. 相似文献
3.
Bismuth chloride was used to catalyze the [2 + 3] cycloaddition between sodium azide with aryl nitriles, aliphatic nitriles, and vinyl nitriles. A number of 5-substituted 1H-tetrazoles were synthesized in water or isopropanol/water mixtures using microwave heating. Good yields were obtained for these reactions when heated for 1 h at 120–160 °C in a 3:1 isopropanol/water mixture. A few of the less reactive nitriles required longer reaction times for good yields. 相似文献
4.
Two proofs are given, one combinatorial, the other by character theory, for the identity, ∏λa1! a2! … an! = ∏λ1a12a2 … nan, where λ ranges over all partitions λ = (1a12a2 … nan) of n. The two demonstrations yield a simple proof of the known formula, det2T(n) = [∏λ1a12a2 … nan]2, where T(n) is the matrix formed by the character table of Sn. Finally a sufficient condition is given so that the permanent of T(n) is zero. 相似文献
5.
Reisdorf W Andronic A Gobbi A Hartmann ON Herrmann N Hildenbrand KD Kim YJ Kirejczyk M Koczoń P Kress T Leifels Y Schüttauf A Tymiński Z Xiao ZG Alard JP Barret V Basrak Z Bastid N Benabderrahmane ML Caplar R Crochet P Dupieux P Dzelalija M Fodor Z Grishkin Y Hong B Kecskemeti J Korolija M Kotte R Lebedev A Lopez X Merschmeyer M Mösner J Neubert W Pelte D Petrovici M Rami F de Schauenburg B Seres Z Sikora B Sim KS Simion V Siwek-Wilczyńska K Smolyankin V Stockmeier M Stoicea G Wagner P 《Physical review letters》2004,92(23):232301
We present a complete systematics (excitation functions and system-size dependences) of global stopping and side flow for heavy ion reactions in the energy range between 0.09A and 1.93A GeV. For the heaviest system, Au+Au, we observe a plateau of maximal stopping extending from about 0.2A to 0.8A GeV with a fast drop on both sides. The degree of stopping, which is shown to remain significantly below the expectations of a full stopping scenario, is found to be highly correlated to the amount of side flow. 相似文献
6.
Simion Breaz 《Czechoslovak Mathematical Journal》2003,53(2):479-489
We present general properties for almost-flat modules and we prove that a self-small right module is almost flat as a left module over its endomorphism ring if and only if the class of g-static modules is closed under the kernels. 相似文献
7.
C. I. Postolache C. A. Simion I. I. Mihalcea 《Journal of Radioanalytical and Nuclear Chemistry》1999,241(1):33-35
Polyacrylic hydrogels were14C- and3H-labeled in three main steps. In the first one, the monomer as sodium salt was14C-labeled at the carboxyl group via the carbonation of vinylmagnesium bromide and [1-14C]acrylic acid was obtained, followed by labeling with tritium via isotopic exchange in heterogeneous catalysis. The monomer
was purified and its radiochemical purity was analyzed using TLC. In the last step, the hydrogel was obtained through radiopolymerization
of the doubly labeled monomer using a60Co source. The oligomers and unpolymerized monomers were eliminated from the hydrogel by swelling in water followed by dehydration
with methanol. 相似文献
8.
I Berceanu A Andronic M Duma D MoisĂ M Petrovici A Pop V Simion A del Zoppo G D’Erasmo G Imme G Lanzano A Pagano A Pantaleo G Raciti 《Pramana》1999,53(3):419-424
The excitation function (EF) data for dissipative processes in 19F + 27Al system in the incident energy interval from 113.5 to 130 MeV are used to obtain the dependence of the charge variance and
of the interaction time as a function of the incident energy. Fluctuations are observed in the EFs of both these secondary
observables. Their correlation is supported by a mechanism based on stochastic exchange of nucleons. 相似文献
9.
J. A. Muller C. Reinhardt C. Fischbach A. Siebenschub V. Stanek N. M. Randall K. Bogoluboff H. Wdowiszewski F. Garrat D. J. Demorest J. R. Cain H. E. Walters F. C. T. Daniels A. J. Field A. Terni P. Malaguti B. S. Evans L. W. Winkler O. L. Barnebey G. L. Kelley J. A. Wiley E. Little J. Costa M. Gröger H. O. Ward P. Slawik W. Hild und F. Simion 《Fresenius' Journal of Analytical Chemistry》1923,63(9):348-359
Ohne Zusammenfassung 相似文献
10.
Marieta?Mure?an-Pop Irina?KacsóEmail author Flavia?Martin Simion?Simon R?zvan??tefan Ioan?Bratu 《Journal of Thermal Analysis and Calorimetry》2015,120(1):905-912
In this study, we obtained a novel salt of ambazone (AMB) with p-aminobenzoic acid (PABA) that exhibits improved solubility and antibacterial activity. The salt was produced by solvent-drop grinding and characterized by powder X-ray diffraction, thermal analysis and Fourier transform infrared spectroscopy. The salt nature of the new form was confirmed by infrared spectroscopy based on the characteristic vibrational band of the protonated amino group. Based on the X-ray powder diffraction data, the compound crystallizes in the triclinic P-1 space group with the following unit cell parameters: a = 14.294 Å, b = 9.162 Å, c = 8.777 Å, α = 95.90°, β = 100.63°, γ = 91.73°. Thermal analysis reveals the thermal events and different decomposition steps of this solid form as compared to the starting compounds. Powder dissolution measurements showed solubility improvement compared with pure ambazone of 2 and 3.3 times in water and phosphate buffer, respectively. Antibacterial tests showed higher activity of the salt to Gram-negative Escherichia coli and Salmonella bacteria as compared to AMB and PABA. The study demonstrates that the pharmaceutical salt of ambazone with p-aminobenzoic acid (AMB–PABA) can be a possible alternative to ambazone in the treatment of infections with Gram-negative bacteria. 相似文献