The changes in photoluminescence and FTIR spectra of porous silicon subjected to oxidation were exdrined. With the increase of okidizing duxation, the relative amount of the Si-H2 surface species on PS decreases even ...The changes in photoluminescence and FTIR spectra of porous silicon subjected to oxidation were exdrined. With the increase of okidizing duxation, the relative amount of the Si-H2 surface species on PS decreases even though the photoluminescence intensity increases. the result suggests that it isn’t SiH2 but Si-O and Si-O-Si on theinterface of PS play a key role in enhancing the pllotoluminescence. A complete photoluminescence mechanism should consider the influence of su-rface state of porous silicon based on the quantum codriement effect model.展开更多
The aim was to develop films with a new mixture of collagen fiber plus polyvinyl alcohol added of oregano or rosemary essential oils at different levels (0%, 2%, 4% and 6%), as well as to assess the antimicrobial acti...The aim was to develop films with a new mixture of collagen fiber plus polyvinyl alcohol added of oregano or rosemary essential oils at different levels (0%, 2%, 4% and 6%), as well as to assess the antimicrobial activity, physical, optical, microstructure and molecular properties in the films. An interaction between the ingredients was observed at the molecular level by FTIR. The amide II and amide III bands, which are important to verify collagen conformation, showed intense peaks in the films. The formation of a network through collagen fibers was produced, acting as a reinforcement in matrix. The films with essential oil had an expressive antimicrobial activity by the steam contact method (micro-atmosphere), mainly for Escherichia coli and Staphylococcus aureus. The mixture of collagen fiber plus polyvinyl alcohol added of essential oils is a promising matrix for application in food as active packaging.展开更多
从北京通州地区3个河流沉积物和天津渤海湾地区4个土壤样品中提取胡敏酸(HA)和非水解碳(NHC),并进行了元素分析、X射线光电子能谱分析(XPS)、傅里叶变换红外光谱(FTIR)和固态13 C核磁共振(13 C NMR)等一系列定性定量的研究。结果显示:...从北京通州地区3个河流沉积物和天津渤海湾地区4个土壤样品中提取胡敏酸(HA)和非水解碳(NHC),并进行了元素分析、X射线光电子能谱分析(XPS)、傅里叶变换红外光谱(FTIR)和固态13 C核磁共振(13 C NMR)等一系列定性定量的研究。结果显示:同一来源的NHC中H/C和O/C比值低于HA的H/C和O/C比值;NHC和HA表面含氧官能团的含量分别为7.6%～10.7%,40.9%～46.7%;13 C NMR和FTIR显示NHC主要由脂肪碳和芳香碳组成;从土壤中比从沉积物中提取的NHC的芳香度高。研究结果表明,与HA相比,NHC的热成熟度高,疏水性强。展开更多
The unfolding of proteins during denaturation by guanidine or urea has been extensively studied. However, the methods hitherto employed usually provide only a limited amount of information on gross changes of such mol...The unfolding of proteins during denaturation by guanidine or urea has been extensively studied. However, the methods hitherto employed usually provide only a limited amount of information on gross changes of such molecular properties as shape, size, or the exposure of buried aromatic residues. CD studies are hampered by high absorption of the denaturants commonly employed in the far ultraviolet region. Recent development in Fourier展开更多
文摘The changes in photoluminescence and FTIR spectra of porous silicon subjected to oxidation were exdrined. With the increase of okidizing duxation, the relative amount of the Si-H2 surface species on PS decreases even though the photoluminescence intensity increases. the result suggests that it isn’t SiH2 but Si-O and Si-O-Si on theinterface of PS play a key role in enhancing the pllotoluminescence. A complete photoluminescence mechanism should consider the influence of su-rface state of porous silicon based on the quantum codriement effect model.
文摘The aim was to develop films with a new mixture of collagen fiber plus polyvinyl alcohol added of oregano or rosemary essential oils at different levels (0%, 2%, 4% and 6%), as well as to assess the antimicrobial activity, physical, optical, microstructure and molecular properties in the films. An interaction between the ingredients was observed at the molecular level by FTIR. The amide II and amide III bands, which are important to verify collagen conformation, showed intense peaks in the films. The formation of a network through collagen fibers was produced, acting as a reinforcement in matrix. The films with essential oil had an expressive antimicrobial activity by the steam contact method (micro-atmosphere), mainly for Escherichia coli and Staphylococcus aureus. The mixture of collagen fiber plus polyvinyl alcohol added of essential oils is a promising matrix for application in food as active packaging.
文摘从北京通州地区3个河流沉积物和天津渤海湾地区4个土壤样品中提取胡敏酸(HA)和非水解碳(NHC),并进行了元素分析、X射线光电子能谱分析(XPS)、傅里叶变换红外光谱(FTIR)和固态13 C核磁共振(13 C NMR)等一系列定性定量的研究。结果显示:同一来源的NHC中H/C和O/C比值低于HA的H/C和O/C比值;NHC和HA表面含氧官能团的含量分别为7.6%～10.7%,40.9%～46.7%;13 C NMR和FTIR显示NHC主要由脂肪碳和芳香碳组成;从土壤中比从沉积物中提取的NHC的芳香度高。研究结果表明,与HA相比,NHC的热成熟度高,疏水性强。
基金Project supported in part by the National Natural Science Foundation of China.
文摘The unfolding of proteins during denaturation by guanidine or urea has been extensively studied. However, the methods hitherto employed usually provide only a limited amount of information on gross changes of such molecular properties as shape, size, or the exposure of buried aromatic residues. CD studies are hampered by high absorption of the denaturants commonly employed in the far ultraviolet region. Recent development in Fourier
