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71.
Christo N. Nanev 《Crystal Research and Technology》1988,23(5):585-594
The shape and size of the gross morphological defect which occurs (in the form of a depression) as a result of the diffusion inhomogeneity in the matter supply on the growing crystal face with supercritical dimensions are investigated. The transition shapes of similar skeletal crystal faces are determined by considering the configuration of the steps which are moving (and accumulating) from the edge toward the centre of the crystal face. The basic parameter which is evaluated, is the width of the macroscopically flat periphery which grows around the depression and its alteration when the crystal is enlarged. The theoretical analysis is carried out by presuming that no transportation of crystallizing material occurs parallel to the crystal face. The calculations are based on the different thicknesses of the Nernst diffusion layer, a magnitude which can be easily determined experimentally by some interferometric technique, over the various regions of the growing face. 相似文献
72.
Johannes K. Schaller Christo G. Stojanoff 《Particle & Particle Systems Characterization》1996,13(3):196-204
A Diesel spray injected into a high-pressure test chamber was investigated with two different holographic techniques. The usual off-axis recording geometry was used to investigate the very early beginning of the injection. Double pulsing of the recording laser facilitated velocity measurements. By using two different reference angles for the two recording the two images can be separated upon reconstruction of the holograms. Thus superior image quality could be achieved. Processes leading to jet formation could be identified: the spray tip is periodically axially decelerated and radially accelerated. Consequently, liquid moves at the tip off axis. The spray consists of fast central region surrounded by a slower outer jet region. The outer jet region exhibits periodic droplet concentration fluctuations which are interpreted as a result of the periodic processes at the spray tip. Some high concentration regions in the outer jet region were investigated using a dark-field holographic technique. This technique permits single droplet velocity measurements and local droplet concentration determination at extremely high droplet concentrations. The most important result of these investigations is that no correlation between the local droplet concentration and the droplet velocity could be found. 相似文献
73.
Iliyana V. Berlinova Plamen V. Iliev Nikolay G. Vladimirov Christo P. Novakov 《Journal of polymer science. Part A, Polymer chemistry》2007,45(20):4720-4732
Double‐hydrophilic in‐chain functionalized macromonomers consisting of poly(N‐isopropylacrylamide) (PNIPAM) and poly(ethylene oxide) were prepared by a multistep procedure including esterification of PNIPAM monoester of maleic acid with α‐methoxy‐ω‐hydroxypolyoxyethylene or its amidation with α‐methoxy‐ω‐aminopolyoxyethylene. The polymerization of the macromonomers was carried out in aqueous solutions. The temperature was the key parameter controlling the polymerization process that was performed in the organized domains formed by the macromonomers below and above the phase transition temperature (Ttr). Polymacromonomers with higher degrees of polymerization were prepared at temperatures just below the Ttr. Static light scattering measurements on dilute aqueous solutions of thermally‐responsive macromonomers and their polymerization products demonstrated that they formed aggregates below the Ttr. Supramolecular structures with low density cores, formed by the polymacromonomers at room temperature, were imaged by SEM. Morphological tuning was achieved by varying both the composition of the copolymer and the concentration of the aqueous solution. The rheological behavior of the polymacromonomers in 25 wt % aqueous solution was compared to that of the respective macromonomers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4720–4732, 2007 相似文献
74.
Christo M. Angelov Dobromir D. Enchev 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):125-128
Abstract Salts of 2,5-dihydro-1,2-oxaphosphole have been prepared by reaction of dimethyl(1,2-alkadienyl)phosphine oxides with halogens, sulfenyl and selenenyl chlorides. The essential influence of tertiary carbenium ions for realization of oxaphospholic cyclization of phosphorylated allenes has been established. 相似文献
75.
Christo D. Manszoff 《Fresenius' Journal of Analytical Chemistry》1914,53(11):716-717
Ohne Zusammenfassung 相似文献
76.
77.
Markov Peter Dimitrova Liliana Ivanov Christo 《Monatshefte für Chemie / Chemical Monthly》1976,107(3):619-624
The interaction between magnesium and biphenyl in liquid ammonia has been studied. It was shown that the metal adduct formed reacts slowly with the reaction medium to give tetrahydroderivatives of biphenyl.A comparative study was carried out in order to reveal the influence of the metal used on the reaction pathway. It was found that the nature of the reaction products markedly differs when lithium, sodium or magnesium were used in the reaction.Possible reaction mechanisms are discussed. 相似文献
78.
2,4,5-Trichloro-2-oxo-1,2-oxaphosphorin-3-enes was sinthesised using the interaction of sulfuryl chloride with dichlorides of 2-chloro-3-alkyl-1,3-alkadienephosphonic acids. 相似文献
79.
Dr. Liliana Kristanova Christo Balarew 《Monatshefte für Chemie / Chemical Monthly》1976,107(3):625-631
The solubility diagram of the system NaAl(SO4)2–CsAl(SO4)2–H2O was investigated at 25°C. This is a system in which -and -alums participate. The fields of cristallization are outlined. There is one wide field of cesium aluminium alum and one, very narrow, of sodium aluminium alum. The eutonic point of the system lies at the composition of the liquid phase corresponding to 27.90 wt.% NaAl(SO4)2 and 0.008 wt.% CsAl(SO4)2. It was found that mixed crystals are not formed in the system. The solid phases were investigated by X-ray diffraction andDTA.
Mit 3 Abbildungen 相似文献
Mit 3 Abbildungen 相似文献
80.
Dr. Ivan M. Panayotov Christo B. Tsvetanov Vassilka Schischkova 《Monatshefte für Chemie / Chemical Monthly》1975,106(3):735-741
With the aid of conductometric measurements the ion equilibria inTHF solutions of 2-naphthonitrile sodium were studied. It was established that in the concentration interval of 10–4–10–5 mol/l the equilibrium ion pairs—free ions is predominant
. The ion pairs are contact (average interion distance about 4.1 Å). In the temperature interval of 25 to 40° the heat of dissociation –H=3.1 kcal/mol, whereas between –40 and –70°–H is 1.26 kcal/mol. At higher concentrations (10–2–10–3 mol/l) triple ion formation is observed. 相似文献