Papers by Keyword: Infrared Spectrum

Abstract: In this article are presented the results of X-ray and IR spectroscopic studies of the structure of the atmosphere - and chemically resistant composite materials based on medium density polyethylene. The presence of specific interactions with polyethylene ingredients in composite materials. It has revealed the appearance on the surface of the active radicals that promote increased interaction fillers with polyolefins, as well as the increase of the elastic-strength characteristics of composite materials are revealed.

Abstract: The possibility of using polymers based on epoxyphenolic binders to obtain fiberglass with an intense level of carbonization has been investigated. The correlation between the pyrolytic transformations intensity and the fire hazard indicators of polymers is shown. It is established that the conditions for the intensive passage of pyrolytic reactions are facilitated by the presence in the matrix system of conjugated aromatic (naphthalene) radicals. The C/H ratio in the carbonized layer is confirmed by the data of IR spectroscopy both at the preparation stage and after exposure to characteristic temperatures.

Abstract: Many Russian and foreign scientists have been studying the processes of hydration of cement binders, but the processes of binders hydration with the use of mineral and organic additives have not been studied enough. The question of the superplasticizers influence on binder compositions consisting of cement and various mineral fillers requires a deep and detailed study in each case. In this regard, the aim of this work is to study the processes of portland cement hydration, modified by organomineral additive. Research was carried out on the study of changes occurring during the structure formation of modified binders by infrared spectroscopy (IR).

Abstract: Using first principles approach, we present the structural, vibrational and dielectric properties of α-SiO₂. The calculations have been carried out within the density functional perturbation theory and linear response formalism using the norm-concerving pseudopotentials and a plane wave basis. All the vibrational modes identified are in good agreement with experiment. The calculated infrared spectra are also in good agreement with available experimental results both for the positions and the intensities of the main peaks. We find that the modes Eu7 and A2u4 splits in two respectively at high hydrostaticpressures. Then we calculate the infrared spectra under high pressure of different orientations. The vibrational modes in different phase transitions are reported and discussed respectively.

Abstract: Optional viscosity average molecular weight of chitosan 3 × 10⁵, the nanophase change microcapsules were mixed in the preparation chitosan spinning dope. Viscometer was used to measure the rheological properties of blend spinning fluid, using infrared spectroscopy,scanning electron microscope (SEM) and the interactions between the studies of phase change fiber surface microstructure. The results show that, blend spinning fluid is generally the basic characteristics of non-Newtonian fluid, with concentration of spinning solution, viscosity increases; temperature rise, viscosity decreased; prolonged standing, viscosity decreased. Chemical changes occurred between chitosan and microencapsulated phase change,no new chemical bonds, for a simple physical blending. By scanning electron microscope, along with the increase in the amount of phase change nanomicrocapsule, fiber surface is obvious.

Abstract: Water-soluble phenolic resin was prepared using sodium hydroxide and ammonia as catalysts. The molecular structure of water-soluble phenolic with different molecular weight was studied by infrared spectrum and the mechanism was discussed. The results show that addition reaction and polycondensation synchronize in the reaction process, while addition reaction dominates in the early stage while polycondensation dominates in the later stage.

Abstract: Nd:YAG nanopowder was prepared by urea co-precipitation method. XRD, TG-DTA, SEM and spectra analysis were utilized to study the properties of the powder. Results indicated that fine Nd:YAG nanopowder can be acquired at 1000°C for 10h. The fluorescence spectra shown that the strongest peak was located at 1061nm, corresponding to the ⁴F_3/2⁴I_11/2 energy level transition of Nd³⁺ ion.

Abstract: As urbanization level of our country improves constantly, urban population will increase dramatically. Then industrial and civil buildings and other facilities will be multiplied, which leads to use plenty of high-performance concrete materials. i.e. China's building materials, especially the use of concrete will be increased year by year^[. And the chemical admixtures is an essential fifth component of concrete^[2-. It has been nearly 50 years since the chemical admixtures were researched,expolited and used in large scale^[.But the water reducer are used most widely, its characteristics is to reduce the water consumption of concrete, and minimize the porosity of concrete. Thereby which enhances its intensity and durability.

Abstract: Abstract:This article studied with emphasis in the caffeine crystallization condition of soaked raises in the crystallization law, separately inspected the ratio of mass of material,the time of soaking,the temperature of soaking,pH effect on the extraction of the caffeine, and the amount of precipitation and other factors on the extraction rate of caffeine to identify the most excellent condition to extract caffeine, in these conditions. Using a melting point and IR identification analysis check the final product which it maybe contain, Have put forward a recovery method precipitated to much phenol of tea polyphenols in experiment course.

Abstract: Application of Combined Collectors in Flotation of Lepidolite were researched, and the object is the gravity concentration tailing of YiChun Tantalum&Niobium Mine. The experiments show: when LZ-00 dispensed by ourselves and mixed amine combined in two to one was used in lepidolite flotation, the flotation indexes is best,and the optimum dosage is 360g/t .The close circuit test can got the lepidolite concentrate with grade 4.12%, recovery 70.37% .It has a remarkable upgrading compared with the target of ore dressing plant . Infrared spectrum showed mineral surface existed chemical adsorption and physical adsorption and hydrogen bonding simultaneously when using LZ-00 and mixed amine to flotation lepidolite .