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81.
Anicuta Stoica-Guzun Marta Stroescu Iuliana Jipa Loredana Dobre Sorin Jinga Traian Zaharescu 《Macromolecular Symposia》2012,315(1):198-204
The development of biodegradable packaging materials, especially from renewable resources is a constant preoccupation of nowadays, because of the environmental problems caused by synthetic polymers. The combination of cellulose with other polymeric materials could be an ecologic alternative and a way to use renewable resources for food packaging. Bacterial cellulose which is produced by microbial fermentation is also a promising material which can be used not only in biomedical application, but also as food packaging material. In this research different composite films between poly(vinyl alcohol)-bacterial cellulose (PVA-BC) were obtained by casting method. The obtained films were UV irradiated for different periods of times from 1 to 10 hours, using a mercury lamp, Philips TUV-30, emitting light mainly at 254 nm. Changes in FT-IR spectra before and after UV irradiation and the modification of transparency and of the swelling characteristics of the films were observed. As it was expected the composites materials are sensitive at UV exposure. 相似文献
82.
Sorin G. Gal 《Results in Mathematics》2012,61(3-4):347-353
In this paper we obtain the differentiated generalized Voronovskaja’s theorem in complex setting with upper and exact quantitative estimates. The results extend that obtained in the real case on [0, 1] in Gonska and Ra?a (Mat Vesnik 61:53–60, 2009) and generalize those obtained in the complex case in Gal (Results Math 53:257–268, 2009). 相似文献
83.
84.
In the frame of industrial risk and propulsive application, the detonability study of JP10–air mixtures was performed. The
simulation and measurements of detonation parameters were performed for THDCPD-exo/air mixtures at various initial pressure
(1 bar < P
0 < 3 bar) and equivalence ratio (0.8 < Φ < 1.6) in a heated tube (T
0 ~ 375 K). Numerical simulations of the detonation were performed with the STANJAN code and a detailed kinetic scheme of the
combustion of THDCPD. The experimental study deals with the measurements of detonation velocity and cell size λ. The measured
velocity is in a good agreement with the calculated theoretical values. The cell size measurements show a minimum value for
Φ ~ 1.2 at every level of initial pressure studied and the calculated induction length L
i corresponds to cell size value with a coefficient k = λ/L
i = 24 at P
0 = 1 bar. Based on the comparison between the results obtained during this study and those available in the literature on
the critical initiation energy E
c, critical tube diameter d
c and deflagration to detonation transition length L
DDT, we can conclude that the detonability of THDCPD–air mixtures corresponds to that of hydrocarbon–air mixtures.
This paper is based on the work presented at the 33rd International Pyrotechnics Seminar, IPS 2006, Fort Collins, July 16–21, 2006. 相似文献
This paper is based on the work presented at the 33rd International Pyrotechnics Seminar, IPS 2006, Fort Collins, July 16–21, 2006. 相似文献
85.
We prove that a sum of free non-covariant duality-symmetric actions does not allow consistent, continuous and local self-interactions that deform the gauge transformations. For instance, non-abelian deformations are not allowed, even in 4 dimensions where Yang–Mills type interactions of 1-forms are allowed in the non-manifestly duality-symmetric formulation. This suggests that non-abelian duality should require to leave the standard formalism of perturbative local field theories. The analyticity of self-interactions for a single duality-symmetric gauge field in four dimensions is also analyzed. 相似文献
86.
Cristina Stere Mihaela‐Corina Iovu Horia Iovu Adrian Boborodea Dan Sorin Vasilescu Simon James Read 《先进技术聚合物》2001,12(5):300-305
The polymerization of ?‐caprolactone initiated by two catalyst systems was studied: (1) carbazole‐potassium in the presence of 18‐crown‐6 ether and (2) NdCl3/TBP/TIBA (neodymiumtrichloride/tri‐n‐butyl‐phosphate/triisobutylaluminium) at the molar ratio 1/3/1. For both initiator systems conversion/time plots were determined and the polymers were characterized by IR, GPC and by 1H‐ and 13C?NMR spectroscopy. Polyesters with the highest molecular weight (M n?44 000 g/mol) were obtained for the polymerizations initiated by the carbazole‐potassium/18‐crown‐6 ether system. The features of the polymerization initiated by the carbazole‐potassium/18‐crown‐6 ether system are discussed on the basis of a simple scheme. The nature of this polymerization is non‐living. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
87.
Ion Grosu Loïc Toupet Gerard Plé Sorin Mager Eugen Mesaros Andreea Varga Elena Bogdan 《Monatshefte für Chemie / Chemical Monthly》2000,131(3):277-286
Summary. The synthesis and stereochemistry of new dibrominated spiro-1,3-dioxane derivatives are reported. Investigations by means
of NMR methods and single crystal X-ray diffraction for two compounds revealed the high regio- and diastereoselectivity of
the bromination reaction of some new spiro-1,3-dioxanes and the asymmetric induction of the chiral carbon atom located in
the spiro skeleton.
Received July 13, 1999. Accepted October 21, 1999 相似文献
88.
We consider two person zero-sum stochastic games. The recursive formula for the valuesvλ (resp.v
n) of the discounted (resp. finitely repeated) version can be written in terms of a single basic operator Φ(α,f) where α is the weight on the present payoff andf the future payoff. We give sufficient conditions in terms of Φ(α,f) and its derivative at 0 for limv
n and limvλ to exist and to be equal.
We apply these results to obtain such convergence properties for absorbing games with compact action spaces and incomplete
information games. 相似文献
89.
A theoretical study of the solvation of ( R)- N-(3,5-dinitrobenzoyl)phenylglycine- and ( R)- N-(3,5-dinitrobenzoyl)leucine-derived chiral stationary phases (CSPs) is presented. Semiflexible models of the chiral selectors are prepared from B3LYP/6-311G** calculations, and these are used in the molecular dynamics simulations of the corresponding interface. The chiral interface is examined for four solvents: 100% hexane, 90:10 hexane:2-propanol, 80:20 hexane:2-propanol, and 100% 2-propanol. Despite the similarities between phenylglycine and leucine, the interfaces are distinct both in terms of the selector orientations at the surface and in the number of hydrogen bonds formed with 2-propanol. We also find that an increase in alcohol concentration alters the preferred orientations of the selectors. 相似文献
90.
Sorin G> Gal 《Journal of Computational Analysis and Applications》2000,2(3):265-276
Starting from the equivalence between the Ditzian–Totik modulus
and
, where
, in this article large classes of functions
are introduced for which the modulus
can be easily calculated. As a consequence, very good estimates for the bestapproximation are obtained. The attempts to estimate or calculate themodulus
can be a very intricateproblem. 相似文献