Реокинетические исследования формирования сетчатых структур в полимерах

Methods of networks formation in different polymers or olygomers are considered. The possibility of rheokinetic description for chemical network formation in elastomers and their binary blends evaluation was shown. These elastomers differ from each other by polarity, reactivity and crosslinking mechanisms. Rheokinetic method represents the new approach for vulcanization regimes, structure and properties of such materials optimizationРассмотрены методы изучения про- цесса образования сетчатых струк- тур в различных полимерах и олиго- мерах. Показана возможность применения реокинетического подхода для оценки процесса формирования химической сетки в бинарных смесях полимеров, различаю- щихся полярностью, реакционной способ- ностью и механизмом сшивания. Реоки- нетический метод представляет собой новый подход к составлению режимов вулканизации эластомеров и оптимиза- ции структуры и свойств материалов на их основе

Noise diodes as a source of entropy for hardware random number generators

The purpose of this article is to describe the use of digital noise generators based on semiconductor noise diodes as part of systems for generating key numerical sequences used in cryptographic security methods. The classification of modern methods of cryptographic protection and the algorithms underlying them are considered. It is shown that ensuring high information entropy in systems for generating encryption keys is possible by using generators of truly random number sequences and cryptographically secure generators of pseudo-random number sequences. A number of disadvantages inherent in widely used sources of physical noise are described, namely: low spectral density of broadband noise, limited frequency range, nonlinearity of the noise spectrum, difficulties in technical implementation when using some methods, especially under conditions of extreme temperatures and exposure to special factors. It has been confirmed that the noise properties of semiconductor noise diodes depend on the composition and constancy of the defect-impurity structure, and defect engineering makes it possible to control their electrical parameters. The study of inhomogeneities and defects in noise diodes and the development on this basis of methods for controlling the level of structural defects made it possible to create technologies for their generation and annealing, and to improve a number of electrical and statistical properties of noise diodes

Влияние молекулярно-массового распределения на поверхностное натяжение расплавов олигомеров

Effect of molecular mass (MM) and molecular-mass distribution (MMD) on surface tension of oligomers has been investigated. Narrow fraction of polyethyleneglycols (from 300 to 40000) and their double and triple mixtures of different composition was used as model. Obtained results prove possibility of regulation surface tension of oligomers and polymers by changing MM and MMD and indicated that stability system’s behaviour increases with enlargement of MMD of oligomer mixtures.Исследовано влияние молекулярной массы (ММ) и молекулярно-массового распределения (ММР) на поверхностное натяжение олигомеров. В качестве модельных систем использовали узкие фракции полиэтиленгликолей в интервале молекулярных масс от 300 до 40000 и их двойные и тройные смеси разного состава. Полученные данные доказывают возможность регулирования поверхностного натяжения олигомеров и полимеров путем варьирования ММ и ММР Показано, что стабильность поверхностного натяжения и поведения системы возрастают с расширением ММР олигомеров

Влияние молекулярной массы на адсорбцию и строение граничных слоев эпоксидных олигомеров на жидкой и твердой границах раздела фаз

The effect of molecular mass on adsorption of epoxy oligomers on water-toluene solution interfaces and a glass dispersed filler surface was investigated. Comparison of results (experimental and calculated on the basis of the theoretical adsorption model of) indicated that adsorption on the water-toluene interface was monomolecular. On the contrary, adsorption on the glass dispersed filler surface was polymolecular.Изучено влияние молекулярной массы (ММ) на адсорбцию эпоксидных олигомеров (ЭО) на границе раздела раствор эпоксидного олигомера в толуоле-вода и на поверхности дисперсного наполнителя (стекла). Проведено сравнение полученных экспериментальных результатов с расчетными параметрами адсорбционного слоя на основе теоретической модели адсорбции. Анализ полученных результатов свидетельствует о том, что адсорбция на поверхности раздела раствор эпоксидного олигомера в толуоле - вода является мономолекулярной, а коэффициент заполнения поверхности меньше, чем при наиболее плотной упаковке, также как и для предельно насыщенного адсорбционнго слоя на поверхности стекла. При этом адсорбция на границе раздела со стеклом была полимолекулярной и с ростом ММ уменьшалась с 6 до 2 монослоев

Study of e+,e− production in elementary and nuclear collisions near the production threshold with HADES

HADES is a second generation experiment designed to study dielectron production in proton, pion, and heavy ion induced reactions at the GSI accelerator facility in Darmstadt. The physics programme of HADES is focused on in-medium properties of the light vector mesons. In this contribution we present status of the HADES experiment, demonstrate its capability to identify rare dielectron signal, show first experimental results obtained from C+C reactions at 2 A GeV and shortly discuss physics programme of up-coming experimental runs. © 2004 Elsevier B.V. All rights reserved. 53 1 49 58 Cited By :1

Rheokinetic investigations of polymer networks formation

Methods of networks formation in different polymers or olygomers are considered. The possibility of rheokinetic description for chemical network formation in elastomers and their binary blends evaluation was shown. These elastomers differ from each other by polarity, reactivity and crosslinking mechanisms. Rheokinetic method represents the new approach for vulcanization regimes, structure and properties of such materials optimizatio

Effect of molecular mass on adsorption of epoxy oligomerson water-toluene solution and dispersed filler interfaces

The effect of molecular mass on adsorption of epoxy oligomers on water-toluene solution interfaces and a glass dispersed filler surface was investigated. Comparison of results (experimental and calculated on the basis of the theoretical adsorption model of) indicated that adsorption on the water-toluene interface was monomolecular. On the contrary, adsorption on the glass dispersed filler surface was polymolecular