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91.
A. N. Gruzintsev G. A. Emel’chenko V. M. Masalov E. E. Yakimov 《Inorganic Materials》2009,45(3):260-263
We have studied the effect of the stop band and coupled photonic modes on the visible luminescence of synthetic opal photonic crystals. The results demonstrate that the position of the photonic stop band in the luminescence spectrum of opal depends on the nanosphere diameter. Optical measurements have been used to determine the refractive index of the photonic crystals and the silica sphere diameter. We have assessed the effect of coupled modes in opal on its intrinsic luminescence spectrum. Coupled modes of visible light in opal can be visualized by applying a matte sapphire plate to the opal surface. 相似文献
92.
Effects of applying a packing pressure on void content, void morphology, and void spatial distribution were investigated for resin transfer molding (RTM) E‐glass/epoxy composites. Packing pressures of zero and 570 kPa were respectively applied to center‐gated composites containing 17.5% randomly oriented, E‐glass fiber preform. Radial samples of these disk‐shaped composites were utilized to evaluate voidage via microscopic image analysis. Two adjacent surfaces were cut from each molded disk in order to evaluate void presence from both through‐the‐thickness and planar views. The packed composite was found to contain almost 92% less void content than the unpacked composite. While void fractions of 2.2 and 2.6% were measured, respectively, from the through‐the‐thickness and planar surfaces of the unpacked composite, only 0.2% void content was observed in the packed composite from both surfaces. Digital images obtained from through‐the‐thickness surface showed that average void size dropped from 59.3 μm in the unpacked composite to 31.7 μm in the packed composite. A similar reduction in average void size from 66.7 to 41.1 μm was observed from the planar surfaces. Circular voids were found to experience higher removal rates at 99%, followed by cylindrical and elliptical voids at 83 and 81%, respectively; while irregular voids show slightly lower void removal rates at 67%. Void proximity to fiber bundles was also observed to affect void reduction as voids located inside fiber tows experience lower void reduction rates. Along the radial direction of the molded disks, removal of voids with different proximities to fibers seems to depend on their arrangement at the end of the filling stage. These findings are believed to ascertain packing as an effective void removal method for RTM and similar liquid composite molding processes. POLYM. COMPOS., 26:614–627, 2005. © 2005 Society of Plastics Engineers 相似文献
93.
V. N. Gadalov S. G. Emel’yanov A. V. Filonovich I. V. Vornacheva I. A. Makarova 《Russian Engineering Research》2018,38(3):189-192
The mechanical properties of Ti6–Al5.5–V–1.8Sn powder titanium alloy are investigated as a function of its structure, which, in turn, depends on its production and heat treatment (quenching and aging). 相似文献
94.
V. N. Gadalov S. G. Emel’yanov E. A. Filatov I. A. Makarova V. G. Sal’nikov 《Russian Engineering Research》2018,38(9):680-686
Structural, subeutectoidal structural, and tool steels are studied. Their boriding is considered. Equipment for electrolytic boriding and a modernized high-temperature casting crucible are presented. The conditions of electrolytic boriding are established. Shortcomings of electrolytic boriding are noted. 相似文献
95.
96.
A. A. Emel’yanenko O. I. Zhabin Yu. N. Polyanchikov 《Russian Engineering Research》2017,37(2):122-124
The end milling of industrial and engineering thermoplastics on numerically controlled machine tools is considered. Specifically, attention focuses on the sources and prevention of machining defects. Recommendations are made regarding the selection of the tool geometry, the cutting conditions, and the mill trajectory. 相似文献
97.
Black iron-chromium (Fe-Cr) bearing oxide pigments are generally utilised as effective colourants in a wide variety of applications. However, in the case of their use within ZnO-containing glazes, they yield an undesirable brown colour instead of expected black colour. In order to understand the colour change in this system, we report the use of focused ion beam (FIB) sample preparation technique followed by the use of analytical transmission electron microscopy (TEM) characterisation techniques. According to the results, the formation of a reaction layer between the pigment and glaze was identified with an average composition of Zn0.48Fe0.79Cr1.32O4. Additionally, the valance of Fe was determined as 3+ in the pigment grain, whereas 2+ in the reaction layer and the glaze, respectively. Therefore, it was concluded that the colour change is occurring as result of the valence variation of Fe, the formation of Zn0.48Fe0.79Cr1.32O4 compound and the outward diffusion of Fe into the glaze. 相似文献
98.
99.
N. N. Ziyatdinov G. M. Ostrovskii I. I. Emel’yanov 《Theoretical Foundations of Chemical Engineering》2016,50(2):178-187
The approach to the problem of designing optimal heat-exchange networks for the reconstruction and synthesis of distillation columns is discussed. It has been proposed to reduce the original discrete-continuous nonlinear programming problem to the modified linear programming assignment problem that takes into account a number of features of separation systems. 相似文献
100.
Emel Ozel Hilmi Yurdakul Servet Turan Matteo Ardit Giuseppe Cruciani Michele Dondi 《Journal of the European Ceramic Society》2010,30(16):3319-3329
Cobalt-doped willemite is a promising blue ceramic pigment, but some important aspects concerning crystal structure, optical properties and technological behaviour are still undisclosed. In order to get new insight on these features, willemite pigments (Zn2?xCoxSiO4, 0 < x < 0.3) were synthesized by the ceramic route and characterized from the structural (XRPD with Rietveld refinement), optical (DRS and colorimetry), microstructural (SEM, STEM, TEM, EDX, EELS) and technological (simulation of the ceramic process) viewpoints. The incorporation of cobalt in the willemite lattice, taking preferentially place in the Zn1 tetrahedral site, induces an increase of unit-cell parameters, metal–oxygen distances, and inter-tetrahedral tilting. It causes shifting and enhanced splitting of spin-allowed bands of Co2+ in tetrahedral coordination, implying slight changes of crystal field strength Dq and Racah B parameter, but increasing spin-orbit coupling parameter λ. Willemite pigments impart deep blue hue to ceramic glazes and glassy coatings with a colouring performance better than commercial Co-bearing colorants in the 800–1200 °C range. Detailed SEM-TEM investigation and microanalysis proved that no diffusion phenomena occur at the pigment–glassy coating interface and that willemite pigments are chemically inert during firing at 1050 °C. 相似文献