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51.
Andrei Rotaru 《Journal of Thermal Analysis and Calorimetry》2012,110(3):1283-1291
Solid fuels represent one of the most used sources of energy in many countries. In terms of ranking for the coal deposits, Romania occupies the 26th place in the world, and the 11th place in Europe, with reserves of 22 million tones of bituminous coal (BC) and 472 million tones of lignite. The National Bituminous Coal Company extracts the most significant amount of BC from the Jiu Valley area, a Subcharpatian basin in the Parang Mountains. In the present article, the BC extracted from the Livezeni depth mine next to Petro?ani city is investigated from the microstructural, thermal, and kinetic point of view, in comparison with a sample from Ural Mountains in Russia. Scanning electron microscopy, FTIR spectroscopy, and thermal analysis (TG/DSC/DTA in air and inert atmosphere) measurements were performed. The KAS isoconversional kinetic method was applied for the in-depth understanding of thermal decompositions and burning processes that occur. Even if the thermal behavior of the two samples is generally similar, the non-isothermal kinetic study revealed important differences in the pathways of the oxidative decomposition of volatiles and formation of coke. Also, the kinetics of coke burning depends only on the amount of fix carbon, regardless of the provenience of BC. 相似文献
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Novel semiflexible polyazomethines containing chromophoric units into azomethine mesogenic core have been synthesised by condensation of a flexible dialdehyde with mesogenic diamines containing fluorene, antraquinone, pyrimidine, azobenzene and benzophenone. The thermotropic behaviour of the resulting polyazomethines was assessed by differential scanning calorimetry, polarised light microscopy and investigations of the miscibility relations. While the pure polyazomethines showed a birefringent viscous texture difficult to be ascribed, by mixing with a liquid crystal dimer, clear Schlieren or marbled textures were observed, indicating a nematic mesophase. The polymers exhibited violet, blue or yellow light emission. 相似文献
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Multipod structures of lamellae‐forming diblock copolymers in three‐dimensional confinement spaces: Experimental observation and computer simulation 下载免费PDF全文
Takeshi Higuchi Marco Pinna Andrei V. Zvelindovsky Hiroshi Jinnai Hiroshi Yabu 《Journal of Polymer Science.Polymer Physics》2016,54(17):1702-1709
The three‐dimensional (3D) confinement effect on the microphase‐separated structure of a diblock copolymer was investigated both experimentally and computationally. Block copolymer nanoparticles were prepared by adding a poor solvent into a block copolymer solution and subsequently evaporating the good solvent. The 3D structures of the nanoparticles were quantitatively determined with transmission electron microtomography (TEMT). TEMT observations revealed that various complex structures, including tennis‐ball, mushroom‐like, and multipod structures, were formed in the 3D confinement. Detailed structural analysis, showed that one block of the diblock copolymer slightly prefers to segregate into the particle surface compared with the other block. The observed structures were further elaborated using cell dynamics computer simulation. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1702–1709 相似文献
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Réka Mokrai Jamie Barrett Dr. David C. Apperley Dr. Andrei S. Batsanov Dr. Zoltán Benkő Dr. Dominikus Heift 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4017-4024
To study pnictogen bonding involving bismuth, flexible accordion-like molecular complexes of the composition [P(C6H4-o-CH2SCH3)3BiX3], (X=Cl, Br, I) have been synthesised and characterised. The strength of the weak and mainly electrostatic interaction between the Bi and P centres strongly depends on the character of the halogen substituent on bismuth, which is confirmed by single-crystal X-ray diffraction analyses, DFT and ab initio computations. Significantly, 209Bi–31P through-space coupling (J=2560 Hz) is observed in solid-state 31P NMR spectra, which is so far unprecedented in the literature, delivering direct information on the magnitude of this pnictogen interaction. 相似文献