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排序方式: 共有342条查询结果,搜索用时 140 毫秒
61.
Tomislav J. Janjić Lidija B. Pfendt Mirjana B. Pasulj 《Monatshefte für Chemie / Chemical Monthly》1984,115(2):125-133
Heterogeneous equilibria in saturated solutions of sparingly soluble diprotic acids: 1,2-, 1,3- and 1,4-benzenedicarboxylic acid, and octanedioic acid, respectively, at ionic strengthI=1 (NaCl) and the temperature of 25 °C, have been investigated. The corresponding equilibrium constants were determined by the application of three independent methods: the formation function method, the method of protons bound to the acid in the solution and the solubility method. The results obtained by these three different methods are in good agreement.
Untersuchung heterogener Gleichgewichte in gesättigten Lösungen schwerlöslicher diprotischer Säuren
Zusammenfassung Es wurden die heterogene Gleichgewichte in gesättigten Lösungen schwerlöslicher diprotischer Säuren (Benzol-1,2-, -1,3- und-1,4-dicarbonsäuren und Oktandisäure) bei einer IonenstärkeI=1 (NaCl) und der Temperatur von 25 °C untersucht. Die entsprechende Gleichgewichtskonstanten wurden mit drei unabhängigen Methoden bestimmt: mit der Methode der Bildungsfunktion, der Methode der an die Säure in Lösung gebundenen Protonen, bzw. mit der Methode der Löslichkeitsbestimmung. Die erhaltenen Ergebnisse stehen in guter Übereinstimmung.相似文献
62.
A new route towards enantiopure hydroxylactones 3 and ent-3, the final chiral precursors in an enantiodivergent synthesis of (+)- and (−)-muricatacin, has been developed starting from d-xylose. 相似文献
63.
64.
Mirjana Stojanovic 《Central European Journal of Physics》2013,11(10):1337-1349
We give an existence-uniqueness result for linear and nonlinear time fractional evolution equations with singularities in corresponding norm in extended Colombeau algebra of generalized functions using fractional analog for Duhamel principle. Paper deals with some nonlinear models with singularities appearing in viscoelasticity and in anomalous processes which have met great interest among researchers who consider them as a challenge in recent years. 相似文献
65.
We study an extensive connection between quotient forcings of Borel subsets of Polish spaces modulo a σ-ideal and quotient forcings of subsets of countable sets modulo an ideal. 相似文献
66.
Thomas Luxbacher Mirjana Čurlin Irena Petrinić Hermina Bukšek Tanja Pušić 《Cellulose (London, England)》2014,21(5):3829-3839
Raw cotton knitted fabrics of Greek, Indonesian, and Indian origin were investigated through surface characterization before and after processing. Surface modifications of all the knitted cotton fabrics were objectively evaluated through zeta potential measurements within a range of the electrolyte solution pHs, and swelling over time. Streaming potential coefficients of different cotton knitted fabrics were applied in order to establish a correlation between the properties of the raw and treated cotton knitted fabrics of different origins. The rate of swelling was calculated from the streaming potential coefficients of the raw knitted fabrics before and after different treatments. Swelling rate for different origins and different treatments of cotton knitted fabrics and the correlation coefficients were obtained using linear regression. Additionally, a data cluster analysis was performed in order to group different origins of cotton, while all the treatments were sorted according to zeta potential and the rate of swelling coefficients. The obtained results showed differences among the clusters, depending on the origin of the cotton knitted fabrics and treatments they were exposed to. 相似文献
67.
Multiscale characterization of antimicrobial poly(vinyl butyral)/titania nanofibrous composites
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Faisal Ali Alzarrug Dusica B. Stojanovic Vera Obradovic Aleksandar Kojovic Jovan M. Nedeljkovic Mirjana Rajilic‐Stojanovic Petar S. Uskokovic 《先进技术聚合物》2017,28(7):909-914
Titania nanofillers were used to reinforce nanofibers in composite mats produced by electrospinning of poly(vinyl butyral) with two different concentrations of polymers. The titania nanoparticles and titania nanotubes were added into an acetic acid/ethanol solution in different contents of 3 and 1 wt%, respectively. The effect of the processing system on the morphology of the produced fibers was analyzed. The antimicrobial poly(vinyl butyral) composite fibers with titanium dioxide nanoparticles and titanium dioxide nanotubes were produced by single and multineedle electrospinning systems. This study reports fabrication of composite nanofibrous mats with significant mechanical and antimicrobial properties at a high production speed, which is promising for commercial applications (health care, photocatalysis, protective clothing, etc.). The reported result revealed an outstanding correlation between values of elastic modulus derived from nanoindentation and dynamic mechanical techniques. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
68.
Biljana Jančić-Stojanović Igor Popović Anđelija Malenović Darko Ivanović Mirjana Medenica 《Chromatographia》2010,71(9-10):799-804
In this paper optimization of chromatographic retention of ramipril and its five impurities employing factorial design is presented. On the basis of preliminary experiments three factors were chosen as inputs (acetonitrile content, pH of the mobile phase and buffer concentration) and retention factor as output. As optimal full factorial design 23 was chosen, factors were examined at two different levels “low” and “high”. Three replications at zero level were added in order to check linearity and complete statistical tests. Relationship between inputs and output is presented in form of second order interaction model. Adequacy of model was explained using analysis of variance. After analysis of results optimal chromatographic conditions were set. Separations were conducted on a C18 column with a mixture of acetonitrile and water phase (TEA in potassium dihydrogen phosphate) in ratio 23:77 v/v. Finally, the LC method was validated and applied for quality control analysis of commercially available tablets. The proposed method is simpler and faster as compared to existing official methods and therefore more adequate for routine control of ramipril during shelf life. Also a general approach which includes factorial design in method optimization offers a possibility for predicting and following the chromatographic behavior of such complex mixtures. 相似文献
69.
Mirjana Stojanovi? 《Journal of Mathematical Analysis and Applications》2009,353(1):244-255
We prove the existence-uniqueness of the solution to the nonlinear n-term time-fractional differential equation with constant coefficients in the Banach space C([0,T]),
(1) 相似文献
70.
Ljiljana Pavlovi? Mirjana Lazi? Tatjana Aleksi? 《Discrete Applied Mathematics》2009,157(13):2938-2944
Let G be a graph and d(u) denote the degree of a vertex u in G. The zeroth-order general Randi? index 0Rα(G) of the graph G is defined as ∑u∈V(G)d(u)α, where the summation goes over all vertices of G and α is an arbitrary real number. In this paper we correct the proof of the main Theorem 3.5 of the paper by Hu et al. [Y. Hu, X. Li, Y. Shi, T. Xu, Connected (n,m)-graphs with minimum and maximum zeroth-order general Randi? index, Discrete Appl. Math. 155 (8) (2007) 1044-1054] and give a more general Theorem. We finally characterize 1 for α<0 the connected G(n,m)-graphs with maximum value 0Rα(G(n,m)), where G(n,m) is a simple connected graph with n vertices and m edges. 相似文献