排序方式: 共有103条查询结果,搜索用时 15 毫秒
1.
Vnira R. Akhmetova Guzel R. Nadyrgulova Tat'yana V. Tyumkina Mikhail Yu. Antipin Usein M. Dzhemilev 《Tetrahedron》2007,63(47):11702-11709
Cyclocondensation of aliphatic diamines with CH2O and H2S (1:3:2 ratio, 0 °C) was carried out to give thiadiazabicyclanes and dithiadiazabicyclanes (1:6:4 ratio), which were previously difficult to synthesize. Symmetric α,ω-bis-1,3,5-dithiazinanes were synthesized at 80 °C by this reaction. The stereochemistry of thiadiazabicyclanes was assigned by 1H and 13C NMR spectroscopy and by theoretical DFT calculations, and of bis-dithiazinanes by X-ray diffraction study in the solid state. 相似文献
2.
Journal of Thermal Analysis and Calorimetry - In the original publication of the article, peak numbers were not given in figure 4. The corrected figure 4 is given below. 相似文献
3.
Stark hole-burning spectroscopy is used to investigate the effective dipole moment change of cresylviolet perchlorate (CVP) in various glass and polymer hosts such as ethanol:methanol (EM), polyvinyl alcohol (PVA), poly (2-hydroxyethyl) methacrylate (PHEMA), polyvinylbutyral (PVB), and formamide. The strong correlation between effective dipole moment change of the guest molecule and the holeburning efficiencies of the host matrices illustrates the sensitivity of the dipole moment change as a direct measure of guest-host interactions. Hole-burning is found to be more efficient as the dipole induced reaction field increases. This relationship is discussed in terms of the unusual hole-burning mechanism suggested for this molecule. The effective dipole moment change of cresylviolet perchlorate ranges from 0.14 to 0.59 Debye. 相似文献
4.
Fuat Güzel Önder Aksoy Gülbahar Akkaya 《Journal of Dispersion Science and Technology》2014,35(4):482-493
Pomegranate pulp has been used as novel adsorbent for removing Cu(II) ions from aqueous solution. The optimum conditions for removal of Cu(II) ions were found to be pH 5.32, biosorbent dose 0.1 g, contact time 120 minutes, initial concentration 50 mg/L, and temperature 30°C. The kinetic data were well fitted to the pseudo-second-order model. The biosorption process agreed with the Langmuir isotherm model. Maximum monolayer biosorption capacity was 7.30 mg/g. Thermodynamic parameters suggest that the biosorption process is spontaneous and exothermic. Desorption studies were carried out with different desorbing agents. 相似文献
5.
A number of photophysical properties of 5H-dibenzo(a,d) cycloheptene have been measured including the emission and triplet-triplet absorption spectra. The quantum yields and decay parameters for the triplet state of this molecule as a function of temperature have also been measured. The results are discussed and compared to those of molecules. 相似文献
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7.
Alexander Alyabyev Ireana Andreyeva Guzel Rachimova 《Journal of Thermal Analysis and Calorimetry》2011,104(1):201-207
The influence of pH shift and NaCl salting on the heat production, oxygen adsorption, and oxygen evolution rates of the unicellular
green halotolerant microalga Dunaliella maritima and the freshwater microalga Chlorella vulgaris were investigated. In the growth process of both microalgae the alkalization of their culture medium was observed. And simultaneously it was
shown that at increasing NaCl salting of cultural medium its acidification occurs. At alkalization and acidification of Chlorella medium the increase of heat production and respiration rates were observed. At alkalization and acidification of Dunaliella culture the adverse effect of decreasing heat production rate was observed. Acidification of culture medium of both algae
led to short-term and sharp increase of photosynthesis measured by polarography and photomicrocalorimeter. 相似文献
8.
Veysel Fuat Hatipolu 《Mathematical Methods in the Applied Sciences》2019,42(16):5258-5265
In this paper, the sinc‐collocation method (SCM) is investigated to obtain the solution of the nonlinear fractional order differential equations based on the relatively new defined fractional derivative, beta‐derivative. For this purpose, a theorem is proved for the approximate solution obtained from the SCM. Moreover, convergence analysis of the SCM is presented. To show the efficiency and the simplicity of the proposed method, some examples are solved, and the results are compared with the exact solutions of the considered equations. 相似文献
9.
Fuat Bayrakceken 《Chemical physics letters》1976,43(1):183-185
The radicals formed in the flash photolysis of 2-methylbut-1-ene and iso-butene and subsequent reactions have been investigated by kinetic spectroscopy and gas liquid chromatography. The extinction coefficients of the β-methallyl radical were measured from the absorption bands. The decay of the radical was second order. The measured rate constant for β-methallyl combination was (2.6±0.3) × 1010 mol?1 & s?1 at 295 ± 2K. 相似文献
10.
Bayrakçeken F Yaman A Hayvali M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(5):983-987
An ultraviolet light-induced photophysical and Photochemical changes of coumarin-481 in cyclohexane have been studied by photolysis technique at room temperature, due to its potential applications in photonics, photochemistry, and electronic spectroscopy. During the optical pumping, coumarin-481 showed photochemical changes, therefore as the concentration of coumarin-481 decreased, a photoproduct concentration increased rapidly. An absorption band of the product was observed at around 250 nm. Photoproduct emission spectra characteristics show that photoproduct molecules can also be used as a laser-dye at different emission frequency. 相似文献