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991.
992.
993.
Most adhesives and binders, including bitumen for asphalt mixture production, are presently produced from petrochemicals after
the refining of crude oil. The fact that crude oil reserves are a finite resource means that in the future, it may become
necessary to produce these materials from alternative and probably renewable sources. Suitable resources of this kind may
include polysaccharides, plant oils and proteins. This paper deals with the synthesis of polymer binders from monomers that
could, in future, be derived from renewable resources. These binders consist of polyethyl acrylate (PEA) of different molecular
weight, polymethyl acrylate (PMA) and polybutyl acrylate (PBA), which were synthesised from ethyl acrylate, methyl acrylate
and butyl acrylate, respectively, by atom transfer radical polymerisation. The rheological properties of these binders were
determined by means of oscillatory testing using a dynamic shear rheometer and combinations of stress/strain, temperature
and frequency sweeps. The results indicate that PEA can be produced to have rheological properties similar to that of ‘soft’
100/150 penetration grade bitumen, PMA with similar rheological properties to that of ‘hard’ 10/20 penetration grade bitumen,
while PBA, due to its highly viscous nature and low dynamic moduli, cannot be used on its own as a binder. The synthetic polymers
were found to be thermo-rheologically simple, and the shift factors, used to produce the dynamic moduli master curves, were
found to fit an Arrhenius function. 相似文献
994.
E. V. Sennikova A. S. Antsyshkina G. G. Sadikov A. V. Bicherov O. Yu. Korshunov G. S. Borodkin M. S. Korobov V. S. Sergienko N. N. Kharabaev A. D. Garnovskii 《Russian Journal of Coordination Chemistry》2008,34(5):315-321
The chelate and molecular complexes of 2-(2-benzazolyl, perimidyl)-indandiones-1,3 were synthesized for the first time. The structures of the ligands (tautomeric forms) and complex compounds were determined from the X-ray diffraction, 1H, 13C NMR, and IR data and the quantum-chemical calculations (RHF SCF in 6-31 G** basis). 相似文献
995.
S. N. Shagabutdinova M. A. Fedotov A. V. Belyaev V. D. Il’yashevich E. I. Pavlova 《Russian Journal of Coordination Chemistry》2008,34(12):917-923
Solid-state rhodium(III) sulfates and their aqueous solutions were examined by IR and electronic absorption spectroscopy, thermogravimetry, X-ray powder diffraction analysis, and 103Rh and 17O NMR spectroscopy. A study of the spontaneous aquation of freshly prepared solutions showed that this process results in an equilibrium between the subsystems of monomeric and oligomeric complexes. It was found that solid-state rhodium(III) sulfates vary in phase composition, basically consisting of dimeric and trimeric complexes. 相似文献
996.
G. I. Nikishin L. L. Sokova V. D. Makhaev N. I. Kapustina 《Russian Chemical Bulletin》2008,57(1):118-123
The solid-phase oxidation of cinnamic, 4-methoxy- and 3,4-dimethoxycinnamic acids with Ce(NH4)2(NO3)6—MHal system leads to β-halostyrenes. Similar procedure in the absence of a metal halide results in a cleavage of the C=C
bond giving the corresponding benzaldehydes.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 114–118, January, 2008. 相似文献
997.
This case report describes a one-stage technique for long-term voice restoration and laryngeal reconstruction in the treatment of Teflon (Dupont, Wilmington, Delaware) granuloma. A patient who presented with severe dysphonia underwent resection of a Teflon granuloma via a lateral laryngotomy. A pedicled strap muscle flap was used to reconstruct the paraglottic space. The muscle flap was positioned through the lateral laryngotomy with direct endoscopic visualization of the endolarynx to ensure correct vertical positioning and medialization of the vocal fold. The muscle flap was secured in this position with suture fixation. The trapdoor piece of cartilage that was elevated to create the window in the lateral thyroid lamina was repositioned over the pedicled muscle flap and reinforced with a titanium miniplate, which was secured to the remaining thyroid cartilage. The patient had excellent voice results and has not required revision or augmentation. Reinforcement of the lateral thyroid lamina using titanium miniplate fixation helps to stabilize the muscle pedicle flap and the position of the vocal fold, in this case resulting in good long-term voice results after a single-stage reconstruction. 相似文献
998.
Y. S. Hong K. C. Kim V. I. Volkov V. D. Skirda C. -H. Lee 《Applied magnetic resonance》2005,29(2):351-361
The diffusion phenomenon of a nonionic surfactant, polyoxyethylene sorbitan monooleate (POE-SMO), micelle in aqueous solution
was investigated by pulsed field gradient nuclear magnetic resonance (PFG NMR) with a high gradient strength of 17.4 T/m at
the diffusion timet
d varied from 3 to 300 ms. This high gradient strength allowed us to measure the slow self-diffusion coefficient of POE-SMO
micelle, and the short diffusion time below 10 ms showed the restricted diffusion of the micelle. At the shortt
d the self-diffusion of the micelle was restricted and the restricted sizes were 1.8, 1.5, and 0.8 μm for the POE-SMO concentration
of 100, 200 and 300 mM, respectively, and 0.6 μm for the POE-SMO only. The possible reason of this restriction was assumed
to be the formation of a spatial network or a micellar clustering. Furthermore, a proton exchange between water molecule and
surfactant OH group on the micelle surface was proposed. With respect to this proposal, the residence time of the proton at
the micelle surface and the thickness of the surface were investigated from proton self-diffusion coefficients by PFG NMR. 相似文献
999.
P.R. Willmott R. Herger M.C. Falub L. Patthey M. Döbeli C.V. Falub M. Shi M. Schneider 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1199-1201
A new ablation target geometry is presented that was used to produce thin films of La1-xSrxMnO3 grown heteroepitaxially on SrTiO3 by pulsed reactive crossed-beam laser ablation. The films were grown in order to perform angle-resolved photoelectron spectroscopy, which demands that the surface be atomically flat. In situ and ex situ analysis shows that this condition was met, even after depositing to a thickness of over 100 nm. PACS 61.10.-i; 61.18.Bn; 68.47.Gh; 71.27.+a; 81.15.Fg 相似文献
1000.
Casey Chun Zhou Eric J. Stoner Kent D. Stewart L. Steven Hollis Edmund D. Matayoshi Gregory M. Brill 《Tetrahedron》2004,60(47):10611-10618
Oritavancin is a semi-synthetic glycopeptide antibiotic which is structurally related to vancomycin. When oritavancin bisphosphate is dried in vacuo with heat, a new compound forms. This new compound is stable only in the solid state and reverts to oritavancin in solution. Highly enriched samples of this compound were obtained by preparative HPLC and the structure of this compound was elucidated by using one and two-dimensional (1H and 13C) NMR spectroscopy in conjunction with computer-assisted molecular modeling. It has been determined that oritavancin adopts a conformation similar to that of vancomycin in solution, while the new compound is the unnatural R-AB-biaryl atropisomer of oritavancin. This is the first observation and isolation of an AB-biaryl atropisomer in an intact member of the vancomycin family of glycopeptide antibiotics. 相似文献