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The effect of melt flow induced by RMF on the meso-and micro-structure of unidirectionally solidified Al–7wt.%Si alloy Benchmark experiment under magnetic stirring

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Journal of Materials Science & Technology 2022年第8期103卷 197-208页

作者： Zs.Veres A.Roósz A.Rónaföldi a.sycheva M.Svéda University of Miskolc Institute of Physical MetallurgyMetal Forming and Nanotechnology(UM)Hungary MTA-ME Materials Science Research Group ELKHHungary

During the last two decades,many algorithms were developed to simulate the solidification process for different casting methods like ingots,continuous casting of steel and the direct chill cast of *** performed under exactly known conditions and with the detailed knowledge of meso-and micro-structures are required for validating these *** aim of this paper is to give a data set to validate these *** solidification experiments were performed by using a rotating magnetic field(RMF)to study the effect of melt flow on the solidified micro-and meso-structure of the Al-7wt.%Si binary *** first and the third 1/3 parts of samples were solidified without magnetic stirring,and the second(middle)1/3 part was solidified by using magnetic *** magnetic induction was 10 m T,the temperature gradient was~7 K/mm,and the sample movement velocity was 0.1 mm/*** the longitudinal section of the sample,the columnar/equiaxed transition(CET),the equiaxed/columnar transition(ECT),the secondary dendrite arm spacing(SDAS),and the macrosegregation(concentration distribution and the amount of eutectic)were *** primary dendrite arm spacing(PDAS)and the grain structure were studied on the cross-section after color etching.

关键词： Al–7wt.%Si alloy Unidirectional solidification RMF magnetic stirring Meso-and microstructure

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Crystal Growth and Nucleation in Glasses in the Lithium Silicate System

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Journal of Crystallization Process and Technology 2016年第4期6卷 29-55页

作者： Galina A. sycheva Grebenshchikov Institute of Silicate Chemistry Russian Academy of Sciences St. Petersburg Russia

The crystal growth and nucleation in glasses in the lithium silicate system have been investigated. Phase separation in ultimately homogenized glasses of the lithium silicate system xLi2O·(100 ﹣ x)SiO2 (where x = 23.4, 26.0, 29.1, and 33.5 mol% Li2O) has been studied. The glasses of these compositions have been homogenized using the previously established special temperature-time conditions, which make it possible to provide a maximum dehydration and removal of bubbles from the glass melt. The parameters of nucleation and growth of phase separated in homogeneities and homogeneous crystal nucleation have been determined. The absolute values of the stationary nucleation rates Ist of lithium disilicate crystals in the 23.4Li2O·76.6SiO2, 26Li2O·74SiO2 and 29.1Li2O·70.9SiO2 glasses with the compositions lying in the metastable phase separation region have been compared with the corresponding rates Ist for the glass of the stoichiometric lithium disilicate composition 33.51Li2O·66.5SiO2. It has been found that the crystal growth rate has a tendency toward a monotonic increase with an increase in the temperature, whereas the dependences of the crystal growth rate on the time of low temperature heat treatment exhibit an oscillatory behavior with a monotonic decrease in the absolute value of oscillations. The character of crystallization in glasses with the compositions lying in the phase separation region of the Li2O-SiO2 system is compared with that in the glass of the stoichiometric lithium disilicate composition. The conclusion has been made that the phase separation weakly affects the nucleation parameters of the lithium disilicate and has a strong effect on the crystal growth.

关键词： Phase Separation Crystal Nucleation Stationary Nucleation Crystal Growth in Phase Separated and Non-Phase Separated Glasses

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Variability of Carbonate Pedofeatures in a Loess-Paleosol Sequence and their Use for Paleoreconstructions

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Journal of Mountain Science 2009年第2期6卷 155-161页

作者： Kovda.I sycheva S. Lebedeva M. Inozemtzev S. Institute of Geography Staromonetny 29119017 Moscow Russia Institute of Soil Science Pyjevsky 7 119017 Moscow Russia Dept. of Soil Science Moscow State University Leninskiye Gory119998 Moscow Russia

Carbonate pedofeatures were studied in details in a loess-paleosol pedocomplex near Kursk, in the central part of the European Plain. The soils studied included a modern Chernozem and five Pleistocene paleosols. Carbonate morphologies and distributions were described in the field. Various morphologies were sampled for further studies including micromorphology in thin sections and submicroscopic studies under a scanning electron microscope. The complex approach of investigation at macro-, micro-, and submicroscopic levels found that most of carbonate pedofeatures are secondary and multiphase. Many of them are related to cryogenic features. The general trend was of decreasing carbonate content in the older paleosols except for increased content in the 1St and 3rd paleosols. Most of carbonate morphologies are similar in the modern soil and paleosols, but pseudomycelium was found only in the modern Chernozem, while soft masses and impregnations are associated with the paleosols. Detailed study on carbonate attributes revealed their specific features in the modern soil and in paleosols. Veins have dissolution features under the modern environment and seem to reprecipitate in form of pseudomycelium. Coatings in paleosols at a depth of the Ist paleosol include specific fine tubes. Powdery soft masses and impregnations in the paleosols are strongly related to cryogenic fissures and paleopermafrost level. Under SEM they consist of tiny crystals, much smaller than in regular soft masses. Several types of hard concretions were identified：rounded, irregular and platy. Small concretions in the modern Chernozem have similar morphology and similar 14C-age as the rounded concretions of the upper paleosols. They are expected to represent the same generation of concretions. Platy concretions fill the bottom part of the large fissures. The 14C-age of hard concretions varies from 3310±80 yrs. B.P in the Ist paleosol up to 20 400 yrs. B.P. in the 3^rd. As a result we found the reflectio

关键词： Loess-paleosol pedocomplex pedogeniccarbonates macr- and microforms

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Volume and Surface Nucleation of Crystals in Glass Based on Blast-Furnace Slag

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Journal of Crystallization Process and Technology 2017年第2期7卷 11-47页

作者： Galina A. sycheva Grebenshchikov Institute of Silicate Chemistry Russian Academy of Sciences St. Petersburg Russia

Using differential thermal analysis, X-ray phase analysis, electron microscopy, and optical microscopy, the nucleation of crystals in glass obtained by blending metallurgical slag with silicon dioxide has been studied. The type of crystallization (homogeneous or heterogeneous, volume or surface) is revealed for each of nine compositions of synthesized glass. It is shown that the first crystalline phase in a volume crystallizing glass is perovskite (CaO·TiO2);in this phase a nucleation of the main phase occurs: melilite (solid solution of gehlenite 2CaO·Al2O3·SiO2 in akermanite 2CaO·MgO·2SiO2). The fundamental characteristics of homogeneous (for a catalizing phase, perovskite) and heterogeneous (for a catalyzed phase, melilite) of crystallization are determined: the steady state nucleation rate Ist, time of unsteady state nucleation τ, crystal growth rate U, and activation energy of frictional flow. The temperature dependences of Ist, τ, and U are obtained. The kinetics of the crystallization of glass is studied and the rates of the surface crystal growth are determined in the glass of nine compositions. The influence of grinding the particles of the original glass on the sequence of deposition of the crystalline phases was studied. Practical recommendations are presented for the use of blast-furnace slag as a raw material for the synthesis of glass and their further utilization.

关键词： Glass Based on Blast-Furnace Slag Volume Nucleation Catalyzed Volume Nucleation Surface Crystal Growth and Nucleation

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细胞遗传学研究在人类健康评价中的意义

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实用预防医学 2016年第6期23卷 766-768页

作者：厄.普.西切娃俄罗斯联邦卫生部A.N.Sysin人类生态学和环境卫生学研究所俄罗斯莫斯科119121

本文概述了现代细胞工程学在细胞基因组学上的应用。通过非侵入法获得颊黏膜细胞,观察细胞基因组遗传学损伤和细胞动力学指标的改变来对人类群体和个体的健康状况进行监测。这与当代医学倡导的4P模式,即预防性(preemptive)、预测性(pred... 详细信息

本文概述了现代细胞工程学在细胞基因组学上的应用。通过非侵入法获得颊黏膜细胞,观察细胞基因组遗传学损伤和细胞动力学指标的改变来对人类群体和个体的健康状况进行监测。这与当代医学倡导的4P模式,即预防性(preemptive)、预测性(predictive)、个体化(personalized)和参与性(participatory)一致。

关键词：多器官细胞标本细胞核损伤微核增生变异监测 4P模式

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