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261.
Yung K. Kim Daniel B. Bourrie Ogden R. Pierce 《Journal of polymer science. Part A, Polymer chemistry》1978,16(2):483-490
Based on dicyclopentadiene and silacyclopentene, two linear polycycloalkylene-siloxane polymer systems have been synthesized and the thermal stability of the raw polymers evaluated by differential scanning calorimetry and thermal gravimetric analysis. The DSC data in nitrogen indicate that both polymer systems have excellent thermal stability. In air, these polymers begin to oxidize at approximately 150°C, with catastrophic oxidation occurring at about 400°C. 相似文献
262.
M. O. Riley Y. K. Kim O. R. Pierce 《Journal of polymer science. Part A, Polymer chemistry》1978,16(8):1929-1941
The synthesis of a number of random and alternating copolymers of a fluorosiloxane and a hybrid fluorocarbon-fluorosiloxane are described, along with property comparisons. The random copolymers were prepared by silanol–chlorosilane condensation, while the alternating copolymer preparation involved the use of the novel silanol—silyl-N-methylacetamido condensation reaction, which was used to produce a high polymer, M?n = 260,000. The physical properties of the two classes of polymers which were compared include: glass transition temperatures, reversion resistance, and thermal and oxidative weight loss. From these comparisons, it was possible to gauge the relative effects of backbone architecture, as well as monomer ratios, upon copolymer properties. Comparison of the thermogravimetric analysis (TGA) of both the random and alternating LS/FCS copolymer systems with the parent LS and FCS homopolymers indicates that the copolymer generally show little variation among themselves, but better thermal characteristics than either of the parents. 相似文献
263.
A stereoselective approach to polyhydroxylated L-Choi derivatives has been developed. The oxidative cyclization of L-tyrosine was optimized to avoid partial racemization and to allow a more efficient scale-up. 相似文献
264.
Poole TL Frisk GV Lynch JF Pierce AD 《The Journal of the Acoustical Society of America》2008,123(2):667-678
This paper introduces a perturbative inversion algorithm for determining sea floor acoustic properties, which uses modal amplitudes as input data. Perturbative inverse methods have been used in the past to estimate bottom acoustic properties in sediments, but up to this point these methods have used only the modal eigenvalues as input data. As with previous perturbative inversion methods, the one developed in this paper solves the nonlinear inverse problem using a series of approximate, linear steps. Examples of the method applied to synthetic and experimental data are provided to demonstrate the method's feasibility. Finally, it is shown that modal eigenvalue and amplitude perturbation can be combined into a single inversion algorithm that uses all of the potentially available modal data. 相似文献
265.
Nuclear spin hyperpolarization through signal amplification by reversible exchange (SABRE), the non-hydrogenative version of para-hydrogen induced polarization, is demonstrated to enhance sensitivity for the detection of biomacromolecular interactions. A target ligand for the enzyme trypsin includes the binding motif for the protein, and at a distant location a heterocyclic nitrogen atom for interacting with a SABRE polarization transfer catalyst. This molecule, 4-amidinopyridine, is hyperpolarized with 50% para-hydrogen to yield enhancement values ranging from −87 and −34 in the ortho and meta positions of the heterocyclic nitrogen, to −230 and −110, for different solution conditions. Ligand binding is identified by flow-NMR, in a two-step process that separately optimizes the polarization transfer in methanol while detecting the interaction in a predominantly aqueous medium. A single scan Carr–Purcell–Meiboom–Gill (CPMG) experiment identifies binding by the change in R2 relaxation rate. The SABRE hyperpolarization technique provides a cost effective means to enhance NMR of biological systems, for the identification of protein–ligand interactions and other applications.Protein–ligand binding interactions are characterized by the para-H2 based hyperpolarization technique SABRE and flow-NMR. Binding to the protein is identified by R2 change of a ligand first interacting with the Ir polarization transfer catalyst. 相似文献
266.
B. Brukner W. Overbeck J. Duclaux J. Errera H. Bechhold L. Gutlohn H. W. Morse G. W. Pierce V. Szidon E. Fouard und J. Manning 《Fresenius' Journal of Analytical Chemistry》1927,71(10):394-398
Ohne Zusammenfassung 相似文献
267.
W. C. Pierce O. R. Torres W. W. Marshall F. Twyman F. Simeon R. Mannkopff und C. Peters 《Fresenius' Journal of Analytical Chemistry》1941,122(3-4):132-135
Ohne Zusammenfassung 相似文献
268.
William B. Gearhart John G. Pierce 《International Journal of Mathematical Education in Science & Technology》2013,44(6):989-1039
An interpretation of the B‐spline in probability is presented, and it is shown how this result could be useful in teaching. 相似文献
269.
270.
Pierce B. Wilson 《Fresenius' Journal of Analytical Chemistry》1862,1(1):106-107
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