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Hits: 19021
Generalized information on the structure of alkaline-borate compounds and glasses is presented, as well as data on the study of the properties and structure of bismuth borate compounds and glasses based on them in double and ternary systems. The intensification of research in the field of bismuth-containing borate systems has stimulated the creation of a number of new glass compositions that are distinguished by low melting point, special electrical properties, a high transparency region, and nonlinear optical properties.
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The Judd-Ofelt parameters have been calculated for Tb
3+ ions in yttrium-aluminum borate glasses co-activated with Tb
3+ and Ce
3+ (X1) and activated only Tb
3+ (X2). The received parameters are: & # 937;
2 = 5.45 * 10-20, & # 937;
4 = 2.82 * 10-20, & # 937;
6 = 3.76 * 10-20 cm2 for X1 and & # 937;
2 = 4.99 * 10-20, & # 937;
4 < / sub> = 2.18 * 10-20, & # 937; 6 = 3.51 * 10-20 cm2 for X2. It is shown that these glasses are promising for the development on their basis of converters of UV radiation into the green-yellow region of the spectrum.
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Hits: 19299
The modes of repainting of glass melt in industrial furnaces of "Chagodoshchensky Glass Factory and Co." Ltd. operating on slag charges are analyzed. It is shown that the efficiency of the process of changing the color of glass is primarily determined by the rational mode of changing the composition and ORP of the charge.
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Hits: 19226
The influence of the environment on the state of the polished surface of optical glasses is determined. The shelf life of polished optical parts before coating or bonding has been found to be shorter than industry standards. Changes in storage conditions at this stage of production can lead to a change in the state of the polished surfaces of optical parts.
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Hits: 19553
The analysis of the granulometric composition of the raw material components of the charge intended for high-performance glass melting has been carried out. It was found that the narrow-fractional composition of sodium sulfate and feldspar practically corresponds to the distribution of silica sand particles, for which about 80% of the mass content falls within the range of 100 250 microns. For carbonate feedstock and soda, a relatively uniform fractional composition with an upper size limit of up to 2000 microns is preferable. At the same time, the proportionality of the particles of the raw materials components with the grain size of quartz sand provides conditions for obtaining a homogeneous mixture and takes into account the technological features of high-performance glass-making
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Hits: 19462
The effect of the use of ultradispersed (nano) materials on the strength characteristics of glass samples of various chemical compositions obtained by high-temperature sintering from powder-forming components has been studied. The nature of the dependence of the strength on the mass content and type of introduced nanomaterials and the chemical composition of the glass has been established.
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Hits: 19504
The possibility of obtaining basalt fiber based on mineral raw materials of Uzbekistan using heating with concentrated solar radiation has been investigated. The phase composition and properties of basalt fiber obtained by traditional technology using gas and solar energy as an energy carrier have been studied. The parameters of the solar furnace in the technological process of obtaining basalt fiber have been determined. The first results indicate the possibility of using concentrated solar energy to create "green" technologies for the production of fibrous materials
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Hits: 20019
The problem of glass strength remains relevant both for special transport and aviation products, and for glass products used in architecture and construction. In practice, the strength of glass is two orders of magnitude lower than its theoretically possible strength. The task of the researchers is to search for methods of glass hardening that would eliminate such a large gap between theoretical and actual values ??of strength.
The most studied methods are those that increase the strength of glass due to compressive stresses on the surface of the glass. The main direction of increasing the strength is to obtain a defect-free glass macrostructure.
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Hits: 20069
The possibility of laser crystallization of lithium-niobium silicate glasses by means of nanosecond laser pulses in the visible and UV ranges has been demonstrated. Irradiation of glasses with the composition (molar fraction,%): 32 Li
2 O; 26 Nb
2 O
5 ; 42 SiO
2 was carried out using a copper vapor laser operating at a sum frequency at a wavelength of 271 nm. Visible radiation was applied to glass containing an additional 1.5% (moles) Nd
2 O
3 . According to confocal Raman spectroscopy, the resulting crystal structures are ferroelectric lithium niobate LiNbO
3
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Hits: 19972
The effect of mechanical dispersion on quartz sand using a centrifugal planetary mill AGO-2 has been investigated. It is shown that at a constant grinding time, but at different intensities of action in the surface layer of sand particles, amorphization of the surface occurs, disordering of the layers, according to FTIR spectroscopy, and a change in some bond angles in the SiO4 tetrahedron. Measurement of the thermal effect of the phase transition & # 945; - in the
& # 946; -crystalline modification of quartz showed that the magnitude of the thermal effect of the transition is reduced for the most powerful impact (50 Hz) by about 25%
