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41.
Matthew Sanger James Thostenson Morgan Hill Hannah Cain 《Applied Physics A: Materials Science & Processing》2013,111(3):829-839
While the emergence of pottery manufacturing is a wide-spread historical occurrence, and one that has garnered the attention of archaeologists for decades, we know very little about how these ancient vessels were created. Through the application of radiographic scanning and computed tomography this paper provides insights into the manufacturing techniques used by the earliest potters in North America. While x-rays have been used to investigate ceramic manufacturing techniques for decades, this paper provides a reassessment of radiography in light of advances in both computed tomography and reconstructive software. 相似文献
42.
Joseph W. Rumer Sheng‐Yao Dai Matthew Levick Laure Biniek David J. Procter Iain McCulloch 《Journal of polymer science. Part A, Polymer chemistry》2013,51(6):1285-1291
Two novel dihydropyrroloindoledione (DPID)‐based copolymers have been synthesized in a two directional approach and characterized (gel permeation chromatography (GPC), ultraviolet‐visible (UV–vis), cyclic voltammetry, and computational models). These planar, broad absorption copolymers show promise for use in organic electronics, with deep energy levels and low bandgaps. The two‐directional Knoevenagel condensation used demonstrates the versatility of DPID as a useful yet underexploited conjugated unit. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
43.
A new platinum acetylide complex based on 6-dialkylaminobenzimidazol-2-yl-vinyl-2-thiophene-5-ylethyne was synthesized in seven steps and 2% overall yield. 相似文献
44.
The hydroxyalkylation reaction has been used to condense benzocrown ethers with various aldehydes and ketones. The condensation reactions are catalyzed by triflic or sulfuric acid. The products from the reactions are bis(benzocrown ethers) and they are formed in good yields (42-98%, 13 examples). 相似文献
45.
In this Letter, we describe a novel three-step, one-pot procedure for the enantioselective synthesis of N-benzyl protected morpholines and orthogonally N,N'-protected piperazines with chiral alkyl groups installed at the C2 position of each heterocyclic core via organocatalysis. This methodology allows for the rapid preparation of functionalized morpholines and piperazines that are not readily accessible through any other chemistry in good to excellent % ee (55-98% ee). 相似文献
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Gregory B. Kharas Matthew J. Lazzarotto Kara A. Ledin Michelle M. Mulvaney Jason R. Nazarof Jean E. Pineda 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(8):1127-1133
Electrophilic trisubstituted ethylene monomers, akyl and alkoxy ring‐trisubstituted methyl 2‐cyano‐3‐phenyl‐2‐propenoates, RC6H2CH[dbnd]C(CN)CO2CH3, (where R is 2,3‐dimethyl‐4‐methoxy, 2,5‐dimethyl‐4‐methoxy‐, 2,3,4‐trimethoxy‐, 2,4,5‐trimethoxy, 2,4,6‐trimethoxy, and 2,4‐dimethoxy‐3‐methyl), were synthesized by the piperidine catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and methyl cyanoacetate, and characterized by CHN elemental analysis, IR, 1H‐ and 13C‐NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (AIBN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C NMR, GPC, DSC, and TGA. High Tg of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 283–306°C range. 相似文献