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排序方式: 共有370条查询结果,搜索用时 15 毫秒
291.
Sruthy Baburaj Jayachandran Parthiban Sarvar Aminovich Rakhimov Rasheedah Johnson Ludmila Sukhomlinova Paul Luchette Steffen Jockusch Malcolm D. E. Forbes Jayaraman Sivaguru 《Photochemistry and photobiology》2023,99(3):901-905
The study evaluates compatibility of stabilizers with dye doped liquid crystal (LC) scaffolds that are used in electronically dimmable materials. The photodegradation of the materials was investigated and suitable stabilizers were evaluated to slow the degradation process. Various types of benzotriazole-based stabilizers were evaluated for stabilizing the liquid crystals. Based on spin trapping experiments, radicals generated upon UV exposure is likely responsible for the degradation of the system. The radical generation is competitively inhibited by the addition of stabilizers. 相似文献
292.
Lebedeva NV Gorelik EV Prowatzke AM Forbes MD 《The journal of physical chemistry. B》2008,112(25):7574-7580
Kemp's triacid (KTA) and cyclohexane tricarboxylic acid (CTA) are small-molecule model systems for acrylic acid polymers, having the same functionalities and stereoregularities as isotactic poly(methacrylic acid) (PMAA) and poly(acrylic acid) (PAA), respectively. As part of an ongoing investigation of radicals produced by photolysis of acrylic polymers, the photochemistry and free radicals from the model systems have been studied using time-resolved EPR spectroscopy as a function of temperature and pH. Radicals are created by direct photolysis of the acids at 248 nm or by sensitized photo-oxidation using quinone triplet states at 308 nm. The two methods of radical production lead to different chemically induced electron spin polarization (CIDEP) patterns in the ensuing radicals, which are simulated and discussed. Well-resolved spectra are obtained at all temperatures for the model system radicals, which are determined to be in the slow motion condition. DFT calculations of the model system radicals are presented and discussed in support of the experimental data. 相似文献
293.
Tori Z. Forbes 《Journal of solid state chemistry》2010,183(11):2516-2521
Lanthanum tantalates are important refractory materials with application in photocatalysis, solid oxide fuel cells, and phosphors. Soft-chemical synthesis utilizing the Lindqvist ion, [Ta6O19]8−, has yielded a new phase, La2Ta2O7(OH)2. Using the hydrated phase as a starting material, a new lanthanum orthotantalate polymorph was formed by heating to 850 °C, which converts to a previously reported LaTaO4 polymorph at 1200 °C. The stabilities of La2Ta2O7(OH)2 (LaTa−OH), the intermediate LaTaO4 polymorph (LaTa-850), and the high temperature phase (LaTa-1200) were investigated using high-temperature oxide melt solution calorimetry. The enthalpy of formation from the oxides were calculated from the enthalpies of drop solution to be −87.1±9.6, −94.9±8.8, and −93.1±8.7 kJ/mol for LaTa−OH, LaTa-850, and LaTa-1200, respectively. These results indicate that the intermediate phase, LaTa-850, is the most stable. This pattern of energetics may be related to cation-cation repulsion of the tantalate cations. We also investigated possible LnTaO4 and Ln2Ta2O7(OH)2 analogues of Ln=Pr, Nd to examine the relationship between cation size and the resulting phases. 相似文献
294.
Clean sulfenylations are observed upon reaction of activated methylenes with phenyl succinimidyl sulfide. When working with diethyl benzylmalonate, the sulfenylated product can be selectively oxidized and thermally fragmented affording phenylsulfenic acid, initially, and diethyl benzylidenemalonate. The developed method was applied using a polymer-supported thioanisole derivative (JandaJel). Formation of the enedicarboxylate documents proof of principle of polymer-supported sulfides as sulfenylating agents onto activated methylenes. 相似文献
295.
B.D. Ngom R. Madjoe J.B. kana Kana A. Forbes A.Y. Fasasi A.C. Beye 《Journal of Physics and Chemistry of Solids》2010,71(5):722-729
We report on the effects of substrate, ambient oxygen pressure and deposition time on the crystal structure, and morphology of Sm0.55Nd0.45NiO3 solid solution nanostructured films synthesized by pulsed-laser deposition. In each film the structure was found to be consistent with a perovskite structure with preferential planes growth and reveals a strong orientation along the orthorhombic (2 1 0) plane of the perovskite subcell for the film deposited on NdGaO3 where highly crystalline films were obtained within 15 min deposition time with a low surface roughness of 8.79 nm. Similar structure is observed on Si (1 0 0) substrate only at O2 pressure of 0.4 mbar. The surface morphology of the different samples shows a net dense film structure with several droplets population. The nano-scaled droplets are in general spherical in shape; a detailed analysis indicates that the laser ablation of this nickelate family is governed to a certain extent by a heat transfer phenomenon. 相似文献
296.
R. H. Forbes 《Fresenius' Journal of Analytical Chemistry》1896,35(1):682
Ohne Zusammenfassung 相似文献
297.
D. Forbes 《Fresenius' Journal of Analytical Chemistry》1870,9(1):387-388
Ohne Zusammenfassung 相似文献
298.
A. H. Church H. C. Sorby und D. Forbes 《Fresenius' Journal of Analytical Chemistry》1869,8(1):467-471
Ohne Zusammenfassung 相似文献
299.
Pumza Mente Dr. Victor Mashindi Dr. Tumelo N. Phaahlamohlaka Thabo N. Monyatsi Dr. Roy P. Forbes Prof. Neil J. Coville 《ChemistryOpen》2021,10(6):618-626
Cobalt oxide nanoparticles (6 nm) supported both inside and outside of hollow carbon spheres (HCSs) were synthesized by using two different polymer templates. The oxidation of benzyl alcohol was used as a model reaction to evaluate the catalysts. PXRD studies indicated that the Co oxidation state varied for the different catalysts due to reduction of the Co by the carbon, and a metal oxidation step prior to the benzyl alcohol oxidation enhanced the catalytic activity. The metal loading influenced the catalytic efficiency, and the activity decreased with increasing metal loading, possibly due to pore filling effects. The catalysts showed similar activity and selectivity (to benzaldehyde) whether placed inside or outside the HCS (63 % selectivity at 50 % conversion). No poisoning was observed due to product build up in the HCS. 相似文献
300.