On the structure and properties of polyamides. XXIV. Supermolecular structure of polycaprolactam in its phase transformations

1965 ◽  
Vol 30 (11) ◽  
pp. 3648-3657 ◽  
Author(s):  
J. Baldrian
2011 ◽  
Vol 011 (9) ◽  
pp. 1098-1104 ◽  
Author(s):  
Ying PEI ◽  
Lina ZHANG ◽  
Huiyuan WANG ◽  
Xianzheng ZHANG ◽  
Min XU

2021 ◽  
Vol 03 (01) ◽  
pp. 79-88
Author(s):  
Davron Rakhmonovich Djuraev ◽  
◽  
Mokhigul Madiyorovna Jamilova ◽  

The article studies the physical properties of rare earth metals, pays special attention to their unique properties, studies the main aspects of the application of rare earth metals in industry. Also, the structure and stability of various forms of sesquioxides of rare earth elements, in particular, europium, as well as the effect of the method of oxide preparation on its structure and properties are considered. The analysis of the ongoing phase transformations of rare earth metals is made. The article emphasizes the use of correct choices to achieve a large technical and economic effect when using rare earth metals in industry. The article is intended for teachers working in the field of physics and chemistry, as well as for students of the specialty "physics and chemistry".


Author(s):  
V.I. Kyrychenko ◽  
V.V. Kyrychenko ◽  
V.P. Nezdorovin ◽  
A.I. Stremetskyi

The article reflects certain applied aspects of a new direction of energy — biosynthetic energy sources, such as bio-oils obtained from technical oils. In particular, there are considered results of the research of the influence of such a characteristic factor of base oils and, first of all, bio-oils as their surface activity on energy efficiency and reliability of operation of friction units lubricated by them under the conditions of the boundary regime of friction. It is proved that the surface activity of oils as an indicator of their functional quality is due to the peculiarities of the structure and properties of their molecules, the energy fields of which evoke certain tribochemical interactions with triboactivated nano-surfaces of friction steels. Separate provisions for evaluating the effect of the tribochemical activity of oils on the process of modifying the steel surfaces of functioning friction units have been formed. The essence of X-ray examination of the influence of lubricating media on the condition of the steel surface by the method of a sliding X-ray beam, analyzing the surface layers with a depth of 0.5–7 mkm. The effect of significant influence of bio-oils obtained from oils on the phase transformations of the structure and properties of the steel surface during tribe tests of samples on friction and wear is revealed. It is established that the effect of obtaining the crystal structure of steel with surface hardening under the deformed layer depends on the tribochemical activity of the proposed three lubricating compositions, which are characterized by the algorithmic growth of such activity. It is proved that the tribochemical activity of bio-oils (in compositions 2 and 3, estimated by the intensity of phase transformations in the surface layers (the effect of Rebinder PO), leads, in turn, to improved friction and wear of lubricated samples compared to the composition 1 low triboactivity. X-structural surfaces analysis of the samples of steel 45 in the initial state and after testing in the media of each of the compositions showed that in the friction processes there is a destruction of the structure of austenite with the release of α-phase (ferrite). It is shown that the intensity of such modification of steel surfaces is progressively amplified in samples lubricated with compositions in accordance with their increasing triboactivity. It was found that with the penetration into the surface layers of steel (from 0.5 to 7 mkm), lubricated with bio-oils of the samples after their tribometer tests, the amount of ferrite increases and the content of austenite decreases. This reduces the deformability of the structure of metal crystals, which leads to the strengthening of its surface under its plasticized layer, and hence the reduction of friction and wear due to the formed intersurface servito-tribopolymer film, resistant to friction. Bibl. 12, Fig. 5, Tab. 3.


2008 ◽  
Vol 106 (4) ◽  
pp. 341-352
Author(s):  
A. Yu. Volkov ◽  
V. A. Kazantsev ◽  
N. I. Kourov ◽  
N. A. Kruglikov

1975 ◽  
Vol 17 (11) ◽  
pp. 2881-2890 ◽  
Author(s):  
T.I. Sogolova ◽  
M.S. Akutin ◽  
D.Ya. Tsvankin ◽  
M.L. Kerber ◽  
B.G. Mudzhiri ◽  
...  

2010 ◽  
Vol 123-125 ◽  
pp. 739-742
Author(s):  
Oleg Figovsky ◽  
Michael Ioelovich

Beta–D-poly-glucopyranose is widespread class of the natural semi-crystalline polysaccharide known as cellulose. This polymer has complicated multi-level supermolecular structure. It is built from elementary nano-fibrils and their aggregates; moreover, each nano-fibril contains ordered nanocrystallites and low-ordered amorphous nano-domains. Therefore cellulose can be a pronounced and eminent representative of nano-structured matters. Such nano matter has peculiar physico-chemical properties depending on specific surface of nano-scale constituents. In this paper, physico-chemistry of the nano-structured cellulose is discussed. In particular, the ability of nano-scale crystallites to co-crystallization and aggregation, as well as their ability to phase transformation through dissolution, alkalization and chemical modification was a subject of the investigation. Structural characteristics of paracrystalline surface layers of nano-crystallites and their effect on physico-chemical properties of the polysaccharide have been discussed.


1964 ◽  
Vol 6 (12) ◽  
pp. 2435-2436 ◽  
Author(s):  
V.P. Solomko ◽  
I.A. Uskov ◽  
T.A. Molokoyedova ◽  
S.S. Pelishenko

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