The dispersion relations of normal modes in the layered constructions are studied. In the frequency region with negative permittivity, we investigate the normal modes near the air-metal and the air-matematerial interf...The dispersion relations of normal modes in the layered constructions are studied. In the frequency region with negative permittivity, we investigate the normal modes near the air-metal and the air-matematerial interfaces and compare them. An extra bulk mode appearing in a pass band of two media is found near the air-matematerial interface, which is different from the air-metal case. Moreover, the bulk mode will be further proved by the attenuated total reflection （ATR） technique, in which the coupling between the incident electromagnetic waves and the normal modes is studied. For p-polarized incident waves, the ATR spectra based on the Otto and the Kretschmann configurations are obtained numerically, where the dips present the excitations of the surface and bulk modes. Furthermore, we also discuss the influences of the middle layer thickness, the incident angle and the damping term on the reflection in detail. It is found that the coupling frequencies and the maximum strength are strongly dependent on the above media parameters.展开更多
A systematically analytical method for the recongnition of blue ballpoint pen ink has been studied by ATR technique of Fourier transform infrared(FTIR) spectrometry. By using this method, a total of 108 blue ink sampl...A systematically analytical method for the recongnition of blue ballpoint pen ink has been studied by ATR technique of Fourier transform infrared(FTIR) spectrometry. By using this method, a total of 108 blue ink samples have been divided to 18 groups depending on the main component. The spectral characteristics of these inks such as peak location, peak intensity etc. were described by the way of pattern recognition; and the species of inks have been able to be recognized by their correlation coefficient(λ). This system has provided a best reliable and nondestructive method for the determination of ballpoint pen ink.展开更多
研究了牛肉蛋白质二级结构稳定性在-18,-23及-38℃不同温度下的变化情况,明确了肉品工业中不同冷冻温度对肉品品质的作用机制。利用了傅里叶变换衰减全反射红外光谱（attenuated total reflectance Fourier transfer infrared spectrosc...研究了牛肉蛋白质二级结构稳定性在-18,-23及-38℃不同温度下的变化情况,明确了肉品工业中不同冷冻温度对肉品品质的作用机制。利用了傅里叶变换衰减全反射红外光谱（attenuated total reflectance Fourier transfer infrared spectroscopy,ATR-FTIR）技术、自动去卷积以及曲线拟合等计算方法,分析了-18,-23及-38℃三个温度下,牛肉肌原纤维蛋白（myofibrillar protein,MP）在冻结—解冻过程中的红外光谱图变化及蛋白质二级结构变性程度。ATR-FTIR结果显示,冻结—解冻过程中牛肉MP红外光谱图峰高、峰面积发生变化,且峰波数发生红移或者蓝移;冻结—解冻后牛肉MP红外光谱图中3 500~3 300cm-1波段的吸收峰强度减弱甚至消失,说明解冻后牛肉MP中的结合水中O—H基团与氨基酸CO基团形成的分子内和分子间氢键断裂;冻结会影响牛肉MP二级结构的稳定性,导致牛肉蛋白质二级结构发生变化,其中除了无规则卷曲比例上升以外,α-螺旋、β-折叠、β-转角含量均下降,造成有序结构向无序结构转变;解冻后,冻结温度为-38℃的处理组牛肉β-折叠增加量大于-23和-18℃处理组,-38℃冻结牛肉MP二级结构的稳定性最好,解冻后蛋白质复性也最好。即蛋白质冷冻变性程度随着冻结温度的降低而减轻,蛋白质二级结构特征保持也越好。该试验研究基于肉品工业生产实际,研究结果从微观层面揭示了冻结温度对牛肉蛋白质变性的影响规律及可能的机制,为冷冻肉冻藏保鲜工艺制定提供了参考。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.10775055)
文摘The dispersion relations of normal modes in the layered constructions are studied. In the frequency region with negative permittivity, we investigate the normal modes near the air-metal and the air-matematerial interfaces and compare them. An extra bulk mode appearing in a pass band of two media is found near the air-matematerial interface, which is different from the air-metal case. Moreover, the bulk mode will be further proved by the attenuated total reflection （ATR） technique, in which the coupling between the incident electromagnetic waves and the normal modes is studied. For p-polarized incident waves, the ATR spectra based on the Otto and the Kretschmann configurations are obtained numerically, where the dips present the excitations of the surface and bulk modes. Furthermore, we also discuss the influences of the middle layer thickness, the incident angle and the damping term on the reflection in detail. It is found that the coupling frequencies and the maximum strength are strongly dependent on the above media parameters.
文摘A systematically analytical method for the recongnition of blue ballpoint pen ink has been studied by ATR technique of Fourier transform infrared(FTIR) spectrometry. By using this method, a total of 108 blue ink samples have been divided to 18 groups depending on the main component. The spectral characteristics of these inks such as peak location, peak intensity etc. were described by the way of pattern recognition; and the species of inks have been able to be recognized by their correlation coefficient(λ). This system has provided a best reliable and nondestructive method for the determination of ballpoint pen ink.
文摘研究了牛肉蛋白质二级结构稳定性在-18,-23及-38℃不同温度下的变化情况,明确了肉品工业中不同冷冻温度对肉品品质的作用机制。利用了傅里叶变换衰减全反射红外光谱（attenuated total reflectance Fourier transfer infrared spectroscopy,ATR-FTIR）技术、自动去卷积以及曲线拟合等计算方法,分析了-18,-23及-38℃三个温度下,牛肉肌原纤维蛋白（myofibrillar protein,MP）在冻结—解冻过程中的红外光谱图变化及蛋白质二级结构变性程度。ATR-FTIR结果显示,冻结—解冻过程中牛肉MP红外光谱图峰高、峰面积发生变化,且峰波数发生红移或者蓝移;冻结—解冻后牛肉MP红外光谱图中3 500~3 300cm-1波段的吸收峰强度减弱甚至消失,说明解冻后牛肉MP中的结合水中O—H基团与氨基酸CO基团形成的分子内和分子间氢键断裂;冻结会影响牛肉MP二级结构的稳定性,导致牛肉蛋白质二级结构发生变化,其中除了无规则卷曲比例上升以外,α-螺旋、β-折叠、β-转角含量均下降,造成有序结构向无序结构转变;解冻后,冻结温度为-38℃的处理组牛肉β-折叠增加量大于-23和-18℃处理组,-38℃冻结牛肉MP二级结构的稳定性最好,解冻后蛋白质复性也最好。即蛋白质冷冻变性程度随着冻结温度的降低而减轻,蛋白质二级结构特征保持也越好。该试验研究基于肉品工业生产实际,研究结果从微观层面揭示了冻结温度对牛肉蛋白质变性的影响规律及可能的机制,为冷冻肉冻藏保鲜工艺制定提供了参考。
