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武培怡, Xianneng Peng, †, Zhengzhong Shao, Xin Chen, *, ‡, David P. Knight, Peiyi Wu, † and Fritz Vollrath‡
Biomacromolecules, Vol. 6, No.1, 2005,-0001,():
-1年11月30日
We used two-dimensional (2D) correlation infrared spectroscopy to study further the potassium-induced conformation transition in Nephila spidroin films. It provided increased resolution and important new information on the sequence of events in the conformation transition process, showing that â-sheet formed from the helical component before they formed from random coil. It also showed more evidence that formation of the 1691cm-1 (turn/bend) peak did not proceed with the same kinetics as the 1620cm-1 (antiparallel â-sheet component) one, so we attribute the 1691cm-1 peak to turns which formed with different kinetics as the antiparallel β-sheets. We present a single coherent and detailed hypothesis for the assembly and secondary structural transition of silk proteins in vivo and in vitro based on our findings and on evidence from other laboratories.
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武培怡, Yi Shen, Feng'en Chen, Peiyi Wu a), Gaoquan Shi b)
J. Chem. Phys., Vol. 119, No.21, 1 December 2003,-0001,():
-1年11月30日
Raman spectra of a polythiophene film measured over a temperature range 298-98K were analyzed using generalized two-dimensional correlation spectroscopy. In the 1600-1250cm-1 region, the asynchronicity of the bands indicates the existence of different species in the investigated polythiophene sample. At least four distinct bands at 1485, 1454, 1418, and 1360cm-1 were identified. Among them, the band at 1454cm-1, attributed to the neutral species of PTh, is found to be sensitive to the temperature-induced structural changes of the polythiophene film, while the bands of the oxidized species are less sensitive to the temperature change during the cooling process.
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【期刊论文】Variable Temperature FTIR Study of Poly(ethylene-co-vinyl alcohol)-graft-poly(є-caprolactone)
武培怡, Hongjin Jiang, Peiyi Wu, * and Yuliang Yang
Biomacromolecules, Vol. 4, No.5, 2003,-0001,():
-1年11月30日
A recently developed technique, i.e., two-dimensional infrared (2D IR) correlation spectroscopy, is used to study the thermal behavior of poly(ethylene-co-vinyl alcohol)-graft-poly(-caprolactone), a new synthesized highly grafted copolymer. The use of the 2D IR approach to analyze temperature-dependent spectra collected in situ during the temperature elevation process effectively enhanced the spectral resolution and revealed details on the hydrogen bonding and conformational change which are not easily detected in the traditional one-dimensional spectra. The sequence of the spectral changes of different OH and CH2 fundamental vibrations during heating the polymer was inferred from the signs of the asynchronous peaks. Evidence that the conformational changes of the methylene groups precede the loosening of hydrogen bonds is provided.
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武培怡, Yi Shen, ‡, Erqiang Chen, §, Chun Ye, Hailiang Zhang, Peiyi Wu, *, Isao Noda, ‖ and Qifeng Zhou§
J. Phys. Chem. B, Vol. 109, No.13, 2005,-0001,():
-1年11月30日
Two-dimensional correlation spectroscopy has been applied to study PMPCS (poly{2,5-bis[(4- methoxyphenyl)-oxycarbonyl]styrene}), a representative example of mesogen-jacketed liquid crystalline polymers. With the precise analysis of a series of Fourier transform infrared (FTIR) spectra of PMPCS recorded at varied temperatures, a reasonable mechanism of the development of liquid crystalline (LC) phase is proposed. Before the phase transition, the conformational change of individual side chains occurs sooner than that of the backbone due to the larger motional freedom of the side chains. After the phase transition, however, the readjustment of still somewhat mobile backbone occurs before the ordered, rigid, and mutually interacting side chains. That is, phase transition leading to the LC phase formation brings in a new cooperative restriction of motions to the segments.
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武培怡, Kanyi Shen, †, ‡, Xiaohui Tian, *, Juhua Zhong, §, Jiaping Lin, Yi Shen, ‡ and Peiyi Wu*
Organometallics, Vol. 24, No.1, 2005,-0001,():
-1年11月30日
Chromium tricarbonyl complexes η6-bonded to 3-amino-9-ethylcarbazole at either the NH2-substituted aryl ring (1) or the unsubstituted aryl ring (2) have been synthesized and their UV-visible absorption spectra determined. In comparison to 2, 1 causes a subtle blue shift in the metal-to-ligand charge-transfer band along with spectral shape changes due to electron transfer from the NH2 substituent to the Cr(CO)3 center.
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