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排序方式: 共有97条查询结果,搜索用时 765 毫秒
1.
Morelos A Albuquerque IF Bondar NF Carrigan RA Chen D Cooper PS Lisheng D Denisov AS Dobrovolsky AV Dubbs T Endler AM Escobar CO Foucher M Golovtsov VL Gottschalk H Gouffon P Grachev VT Khanzadeev AV Kubantsev MA Kuropatkin NP Lach J Lang Pengfei Li Chengze Li Yunshan Luksys M Mahon JR McCliment E Newsom C Pommot Maia MC Samsonov VM Schegelsky VA Shi Huanzhang Smith VJ Tang Fukun Terentyev NK Timm S Tkatch II Uvarov LN Vorobyov AA Yan Jie Zhao Wenheng Shuchen Z Zhong Yuanyuan 《Physical review letters》1993,71(21):3417-3420
2.
Morelos A Albuquerque IF Bondar NF Carrigan RA Chen D Cooper PS Dai Lisheng Denisov AS Dobrovolsky AV Dubbs T Endler AM Escobar CO Foucher M Golovtsov VL Gottschalk H Gouffon P Grachev VT Khanzadeev AV Kubantsev MA Kuropatkin NP Lach J Lang Pengfei Li Chengze Li Yunshan Luksys M Mahon JR McCliment E Newsom C Pommot Maia MC Samsonov VM Schegelsky VA Shi Huanzhang Smith VJ Tang Fukun Terentyev NK Timm S Tkatch II Uvarov LN Vorobyov AA Yan Jie Zhao Wenheng Zheng Shuchen Zhong Yuanyuan 《Physical review letters》1993,71(14):2172-2175
3.
Teixeira-Neto É Leite CA Cardoso AH Medeiros da Silva MC Braga M Galembeck F 《Journal of colloid and interface science》2000,231(1):182-189
Poly(styrene-co-acrylamide) (PS-AAM) latex was prepared, fractionated by sedimentation under gravity, and characterized by PCS, infrared spectra, secondary and backscattered electron imaging in the scanning electron microscope, and electron spectroscopy imaging in an analytical transmission electron microscope. Three latex fractions were obtained. The lower fraction was opalescent and its particles were the more uniform, concerning size, chemical composition, and topochemical features. This lower fraction was still further fractionated by zonal centrifugation in a density gradient, yielding two fractions with similar macrocrystal-forming abilities but different sizes and chemical compositions. These results confirm those previously obtained for the PS-HEMA latex. Copyright 2000 Academic Press. 相似文献
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Der‐Lii M. Tzou Lin‐Kai Ni Mei‐Man Chen Min‐Chuan Chiou Li‐Chou Chen Shan‐Te Hsu Kuo‐Lung Ku Chien‐Chung Cheng 《中国化学会会志》2013,60(9):1107-1112
Solid‐state Nuclear Magnetic Resonance (ss‐NMR) 13C single‐pulse excitation spectroscopy in combination with the magic‐angle spinning (MAS) technique was applied to a series of Phalaenopsis tissues, including the leaf, sheath, stem, and root, at different growth and spiking periods. Compared with{1H}/13C cross‐polarization MAS spectra, the 13C single‐pulse excitation MAS spectra displayed very distinct spectral patterns, recognizable as fingerprints of the tissues studied. 1Here, we demonstrate that solid‐state 13C single‐pulse excitation NMR spectroscopy provides a direct and robust analytical tool for studying the various tissues of Phalaenopsis in different growth and spiking induction periods. 相似文献
7.
D. L. Tzou P. Desai A. S. Abhiraman T.-H. Huang 《Journal of Polymer Science.Polymer Physics》1995,33(1):63-69
Determination of the orientational order of morphological components in polyethylene terephthalate (PET) is sought through quantitative application of two-dimensional rotor synchronized magic angle spinning (ROSMAS) 13C NMR technique. Previous study in our laboratories had established a procedure for resolution of the carbonyl carbon (CA) and glycol ethylene carbon (GE) resonances into those corresponding to four morphological components.1 Due to paucity of sidebands in the GE resonances, the focus has been on the CA resonances in this attempt to obtain orientation distributions. A set of PET fibers possessing a broad range of crystalline and orientational order has been used to infer the meaning of NMR-based orientation measurements vis-a-vis other techniques. A surprising finding of this study is the observation that the orientational orders of the broad component in the 13C CP/MAS spectrum and the narrow component are very similar in these fibers. ©1995 John Wiley & Sons, Inc. 相似文献
8.
Tzou DL 《Solid state nuclear magnetic resonance》2005,27(4):209-214
Simple 2D 13C/15N heteronuclear correlation solid-state NMR spectroscopy was implemented to resolve the 15N resonances of the alpha and beta anomers of three amino monosaccharides: galactosamine (GalN), glucosamine hydrochloride (GlcN), and N-acetyl-glucosamine (GlcNAc) labeled specifically with 13C1/15N spin pairs. Although the 15N resonances could not be distinguished in normal 1D spectra, they were well resolved in 2D double CP/MAS correlation spectra by taking advantage of the 13C spectral resolution. The alpha and beta resonances shifted apart by 3-5 ppm in their 13C chemical shifts, and differed by 1-2 ppm in the extended 15N dimension. Aside from this, the detection of other 13C/15N correlations over short distances was also achieved arising from the C2, C3 and CO carbons present in natural abundance. 2D double CP/MAS chemical shift correlation NMR spectroscopy is a simple and powerful technique to characterize the anomeric effect of amino monosaccharides. Applications of the 2D method reveal well-resolved 15N and 13C chemical shifts might be useful for structural determination on carbohydrates of biological significance, such as glycopeptide or glycolipids. 相似文献
9.
Two-dimensional cross polarization (CP), magic angle spinning (MAS) rotor synchronization NMR spectroscopy has been used to determine quantitatively the molecular orientational distribution function on hot-drawn Nylon 6. Both films and fibers are studied that had been thermally deformed at temperature above Tg, from 60 to 175°C at draw ratios in the range of 1-5.5. In the two-dimensional NMR spectrum, the sidebands that intrinsically originate from the chemical shift anisotropy reveal the degree of molecular orientational order. No preferential orientational order is detected for the sample without thermal deformation, and the highest degree of order is observed for samples which have been hot drawn above Tg at ratios ca. 5. Based on the aggregate model the maximum achievable order parameters are determined. © 1994 John Wiley & Sons, Inc. 相似文献
10.
The thermal conductivity, κ, of NbSe3 has been measured by novel self-heating techniques that allowed the electric field dependence of κ to also be measured. Measurements were made from 35 K to room temperature. Above the charge density wave transitions, the phonon thermal conductivity is 4–7 times the electron thermal conductivity, and it rises smoothly below the transitions, indicating that phonon-phonon scattering predominates. Phonon mean free parths have been estimated at 187 A° at 60 K and 60 A° at 150 K. No clear anomalies were observed at the phase transitions, giving upper limits to changes in the phonon mean free path. No field dependence of κ was observed. 相似文献