蒙药草乌炮制前后二维红外相关光谱的分析研究

采用二维相关红外技术,并借助于变温过程所跟踪的动态光谱对蒙药生草乌进行了分析研究.蒙药生草乌和制草乌的一维谱图较相似,导数光谱进一步分析,1 745,1 468,1 337 cm-1处吸收峰在经过酸奶炮制之后向底波数位移,1 657 cm-1处吸收峰在经过炮制之后向高波数位移,而二维红外相关谱则差别较大,在1 300～800 cm-1波数范围内,生品的二维红外光谱存在3个主要的自动峰(1 650,1 560,1 470cm-1),其中以1 560 cm-1峰最强.自动峰和交叉峰形成明显的3×3的对称分布,均为正相关;制草乌在这一范围内的自动峰主要在4个区域,1 220与1 200 cm-1两个吸收峰组成的一个区域,1 140和1 070 cm-1两个尖锐的峰区,以及1 000～900 cm-1区域内宽大重叠的峰,各自动峰均为正相关.凭借二维红外相关谱上的自动峰和交叉峰町以较直观地鉴别牛草乌和制草乌,而且还可以揭示两者相应各官能团的变化规律.该法快速、准确,可为鉴别药材加上后结构的变化规律提供一种新的方法和手段.     

红外光谱法与药用玫瑰真伪的分析与鉴定

文章采用红外光谱法(FTIR)并结合二维相关光谱分析技术分析鉴定了药用玫瑰(药材对照品)及其混淆品月季和蔷薇。在一维红外光谱中三者的谱图较为一致,但药用玫瑰在1 318 cm-1波数处的峰不明显 ,而月季和蔷薇的1 318 cm-1峰明显,且较尖。在高分辨的二阶导数谱中药用玫瑰和月季分别在1 617和1 618 cm-1处具有芳香类指纹特征峰,而蔷薇的峰则在1 612 cm-1波数处,相差了5～6 cm-1。在1 044 cm-1处的峰, 蔷薇糖类化合物的指纹特征峰较明显,月季和药用玫瑰不明显。观测二维相关红外谱,三者都存在1 620,1 560和1 460 cm-1的芳香类化合物的自动峰,不同的是月季和蔷薇还存在一个较明显的1 660 cm-1的肩膀峰。药用玫瑰、月季和蔷薇在850～1 250 cm-1范围内的二维相关红外光谱差别很大,药用玫瑰1 050 cm-1的糖类化合物自动峰强度最大,而月季的峰较弱,而蔷薇没有此峰。谱图的三级鉴定验证了药用玫瑰、月季和蔷薇在糖苷类化合物和芳香类化合物的相对含量上都是不一致的。结果表明,运用红外光谱法可以快速有效地分析和鉴定药用玫瑰及其混淆品。     

黄芩及其提取物红外光谱与二维相关光谱的鉴别

采用二维红外相关技术,对黄芩原药材、饮片及其提取物进行分析研究。在一维红外光谱中,各样本间的谱图十分相似,导数光谱分析发现,经过炮制之后在1 745和1 411 cm-1处吸收峰向高波数位移,1 357 cm-1处吸收峰向低波数位移。二维红外谱图显示的药效组分特征差异明显,生黄芩在1 300～1 800 cm-1波数范围内有4个特征峰,以1 575 cm-1最强;黄芩片的自动峰有3个区域;酒黄芩的自动峰有2个区域。各区域内自动峰均为正相关。不同样品总苷提取物的一维谱图显示, 在1 615, 1 585, 1 450 cm-1(苯环骨架振动)和1 658 cm-1(CO)附近均有特征吸收,二阶导数谱图给出在1 656 cm-1(黄酮的CO)附近有特征峰,推测共有的成分为酚苷类化合物。二维谱图在800～1 800 cm-1波段均体现苯环骨架振动的5个自动峰1 366,1 420,1 508,1 585,1 669 cm-1。可见红外光谱宏观指纹技术可提供大量整体信息,能够较准地把握黄芩的整体质量。可用于研究黄芩药材及饮片特征的相关性。     

温度对鱼鳞胶原蛋白二级结构的影响

从草鱼鱼鳞中提取酶溶性胶原蛋白(PSC),通过SDS-PAGE电泳分析为典型Ⅰ型胶原蛋白且达到电泳纯。在此基础上利用傅里叶变换红外光谱(FTIR)、拉曼光谱(Raman)和圆二色谱(CD)研究了温度对鱼鳞胶原蛋白二级结构的影响。FTIR分析表明：鱼鳞胶原蛋白具有典型的胶原蛋白特征吸收带,酰胺Ⅰ、酰胺Ⅱ和酰胺Ⅲ带的特征吸收频率分别出现在1658,1552和1238cm-1处。随温度升高,酰胺A和酰胺B峰位向低波数移动,1658cm-1处吸收峰裂解成多个吸收峰;1552cm-1处的吸收峰在35℃微略红移,随后发生明显蓝移;1238cm-1处吸收峰随温度升高向低波数移动。在拉曼光谱中,胶原蛋白的酰胺Ⅰ、酰胺Ⅱ和酰胺Ⅲ带的特征吸收频率分别出现在1669,1557和1245cm-1处,都较红外光谱的波数高;此外,921和855cm-1处脯氨酸的特征谱峰在拉曼光谱中体现出来。圆二色谱分析表明,胶原蛋白溶液在221.6和204.4nm分别有一正、负峰,具有典型胶原蛋白三螺旋结构的特征圆二色谱峰型。胶原蛋白冻干品的FTIR光谱和Raman谱线大都在35～60℃时发生波数和强度改变,而胶原蛋白乙酸溶液的CD谱线在20～35℃之间发生剧烈改变。由此可以判断胶原蛋白在固态和溶液状态下,变性温度存在一定差异,胶原蛋白冻干品比其乙酸溶液更稳定。     

硬脂酸亚甲基面内摇摆振动二维红外光谱研究

在293~393K温度范围内,分别采用一维红外光谱、二阶导数红外光谱和二维红外光谱测定硬脂酸亚甲基面内摇摆振动(ρCH2)。实验发现:在700~750cm-1范围内,硬脂酸ρCHα存在"第一特征谱带"和未见文献报道的"第二特征谱带"。并进一步研究了温度对于硬脂酸ρCH2红外吸收强度及变化顺序的影响。     

八角茴香与其伪品莽草的红外光谱三级鉴定研究

采用红外光谱三级鉴定的方法区分和鉴别了八角茴香及其伪品莽草。红外光谱三级鉴定即依次采用一维红外光谱、二阶导数谱和二维相关红外光谱,分辨率逐渐提高,谱图的差别也进一步放大。一维谱图中,两者整体峰形比较相似,但在3 400 cm-1附近八角茴香只出现一个特征峰3 392 cm-1,而莽草则出现3 482和3 387 cm-1两个特征峰。二阶导数谱在850～1 180 cm-1波段八角茴香的几个强峰峰强相对比较接近,其中1 015 cm-1为图中最强峰,而莽草的最强峰在1 070 cm-1附近;在1 180～1 500 cm-1波段八角茴香在1 469,1 454,1 442 cm-1附近的３个特征峰峰强明显强于1 292,1 276,1 266 cm-1附近的特征峰,而莽草则刚好相反。二维相关红外光谱中差异更明显,850～1 165 cm-1波段八角茴香在主对角线上的自动峰较强峰出现在1 153和1 000 cm-1,而莽草峰强较强的自动峰出现在911和878 cm-1;1 165～1 500 cm-1波段八角茴香呈现2个自动峰,而莽草则出现5个自动峰。可见红外三级鉴定方法是一种快速有效的鉴定中药材的方法。     

肺癌患者及正常人指甲的红外光谱比较研究

用傅立叶变换红外光谱研究了6例肺癌患者和16例正常人手指甲的红外光谱.结果表明,它们在峰形,峰频率,峰强等方面均有差异:在3315cm-1处蛋白质酰胺A带N-H峰向低波数频移,而在3061cm-1处蛋白质酰胺B带N-H峰向高波数频移;在1539cm-1处蛋白质酰胺I带和1396cm-1处角蛋白脂质CH3弯曲振动向低波数频移;CH2和CH3的相对吸收强度比值A2848/A2872和A2918/A2956在肺癌患者指甲中要小于正常人指甲;在1072cm-1处核酸分子磷酸二酯基团PO-2的对称伸缩振动的相对吸收强度明显高于正常人指甲;在1041cm-1处糖原C-O的伸缩和弯曲振动峰向高波数频移了约6cm-1.     

老鹳草中药材红外光谱的分析与鉴定

采用红外光谱、二阶导数光谱和二维相关红外光谱对来自黑龙江、吉林、辽宁三省的老鹳草中药材进行了分析。不同产地的老鹳草的红外光谱都具有1 730和1 337 cm-1等表征鞣质类成分的特征吸收峰和1 618和1 318 cm-1波数表征草酸钙的特征峰。其中还发现在1 370 cm-1的C—H弯曲振动区和1 230 cm-1的C—O伸缩振动区三产地老鹳草具有一定的差异性。在高分辨的二阶导数谱中, 1 509,1 204,764和763 cm-1附近的表征鞣质类成分的吸收峰更明显,三产地老鹳草在CO羰基伸缩振动区表征了脂肪类化合物的不同;尤其是在二维相关光谱上,各自的自动峰具有显著的差异性,黑龙江的老鹳草出现了7个自动峰,其中1 621 cm-1处自动峰最强;而在吉林和辽宁产地的老鹳草中同样出现了4个自动峰,前者1 580 cm-1处的自动峰最强,后者在1 649 cm-1处自动峰最强。该方法直观、简单、方便、快速,可以作为鉴别和鉴定同种不同产地老鹤草的一种新方法。     

七种牛肝菌的红外光谱鉴别

运用傅里叶变换红外光谱、二维相关谱及主成分分析对7种同属牛肝菌进行分析鉴别。结果显示：7种牛肝菌的原始光谱总体特征相似,主要由蛋白质、多糖等的吸收峰组成,但在吸收峰强度、位置仍存在差异。对样品进行二维相关红外光谱分析,在二维相关红外光谱1 680～1 300 cm-1范围内,茶褐牛肝菌和双色牛肝菌出现了6个明显的自动峰;小美牛肝菌出现了5个明显的自动峰;灰褐牛肝菌和美柄牛肝菌出现4个明显自动峰;美味牛肝菌和铜色牛肝菌自动峰相对较少,只出现了3个明显的自动峰;而且自动峰和交叉峰的强度、位置也存在较大差异。同样在二维相关红外光谱1 150～920 cm-1范围内,不同牛肝菌的同步谱中自动峰和交叉峰的数量、强度和位置也不同。对光谱1 800～800 cm-1范围内的二阶导数进行主成分分析,所有样品均区分开,其分类正确率达100%。结果表明,傅里叶变换红外光谱结合二维相关红外光谱或者主成分分析可以有效地区分茶褐牛肝菌、小美牛肝菌、双色牛肝菌、灰褐牛肝菌、美柄牛肝菌、美味牛肝菌和铜色牛肝菌。该方法对于分类鉴别蘑菇是一种快速、准确、有效的方法。     

蛋白质二级结构的二维红外相关光谱模拟研究

利用Voigt函数模拟了蛋白质二级结构的红外光谱吸收带和酰胺I带,其中1680cm-1吸收峰被严重叠加。为了研究二维红外相关光谱分析技术对叠加峰的分辨能力,选取1680cm-1吸收峰作为研究对象。当1680cm-1单峰峰高发生变化时,其同步谱中自相关峰能准确的反映出来。当1680cm-1和1640cm-1双峰峰高都发生变化时,其同步谱中自相关峰不但能准确反映出这两个峰的变化,还能获得1680cm-1子峰对外部扰动的灵敏度高于1640cm-1子峰的信息。它们同步谱中负交叉峰说明了1680cm-1和1640cm-1的变化取向相反,异步谱中该位置的负交叉峰说明了1640cm-1的变化快于1680cm-1。二维相关分析的结果和模拟吸收带假设的变化情况一致。研究表明二维红外相关光谱技术具有高分辨率、高灵敏度等优点,可以用于研究严重叠加的酰胺I带,获取蛋白质二级结构变化的相关信息。     

Self-organization of five species in a cyclic competition game

Cyclic competition game models, particularly the “rock–paper–scissors” model, play important roles in exploring the problem of multi-species coexistence in spatially ecological systems. We propose an extended “rock–paper–scissors” game to model cyclic interactions among five species, and find that two of the five can coexistent when biodiversity disappears, which is different from the “rock–paper–scissors” game. As the number of fingers is five, we named the new model the “fingers” game, where the thumb, forefinger, middle finger, ring finger, and little finger cyclically dominate their subsequent species and are dominated by their former species. We investigate the “fingers” model in two ways: direct simulations and nonlinear partial differential equations. An important finding is that the number of species in a cyclic competition game has an influence on the emergence of biodiversity. To be specific, the “rock–paper–scissors” model is in favor of maintaining biodiversity in comparison with the “fingers” model when the variables (population size, reproduction rate, selection rate, and migration rate) are the same. It is also shown that the mobility and reproduction rate can promote or jeopardize biodiversity.     

Contrastive analysis on tone between Putonghua and Taiwan Mandarin

The differences of the pitch and duration of Chinese syllables between Putonghua （PTH） and Taiwan Mandarin （TM） were studied. The speech materials to be used are not only isolated syllables, but also sentences. The results reveal that： For the isolated syllables, T1 and T2 in TM are influenced by Minnan dialect, therefore their pitch are lower than those in PTH. T3 is fall-rise in PTH, while it is fall in TM. Moreover, the syllable duration sequence for different tone is T3〉T2〉T1〉T4 in PTH, while it is T1〉T2〉T3〉T4 in TM. For the syllables in sentences, T2 is mid-rise in PTH, while it is mid-level in TM. And the T3 is longer than T4 but shorter than T1 or T2 in PTH, while it is the shortest in TM. Furthermore the effects of prosodic phrase boundary on duration for different tones are almost the same in PTH, but the lengthening part of T1 or T2 is longer than that of T3 or T4 in TM.     

Experimental study on downstep in Chinese intonation

Downstep in pitch contour of Chinese Putonghua is examined using subtly designed sentences by controlling tone combinations. The results show both automatic and nonautomatic downstep phenomena exist in Chinese. In non-automatic downstep, low tones compress downwards the pitch range of the following syllables. and the main influence of downstep is on topline. Low tone not only lower the topline behind it, but also raise the high tones before it, the effects are compatible with each other. In automatic downstep, the topline of pitch contour in intonational phrase is presented as a linear downtrend, but it differs among speakers due to the effect of personal stress practice. In comparison with downstep phenomenon in other tone or non-tone languages, the downstep ratio in Chinese is not constant, and the domain of downstep is not limited within the adjacent tones.     

Abelian-Higgs phase of SU(2) QCD and glueball energy

It is shown that SU(2) QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741(2006)1].     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Signal generation in an isotropic medium in scanning electron acoustic microscope

Based on the research in Ref. [5][Materials Science and Engineering, 1989; A122： 57 63], an improved model of heat source is set up, the different modes of Lamb wave in an isotropic sample generated by a chopped electron beam at frequency f are obtained with integral transform and normal function expansion method, and the output signal of PZT coupled at the back surface of the sample is found out. The generation mechanism of SEAM （Scanning Electron Acoustic Microscopy） signal is discussed. It shows that the SEAM is a near field imaging technique with high spatial resolution and its best lateral spatial resolution is about 2√2α （α is the radius of the focused electron beam）. Some of experimental results of SEAM images are presented in the paper and it shows that the spatial resolution of SEAM is better than 0.5 μm and smaller than the thermal diffusion length of the sample. Therefore the character of near field imaging in SEAM is also proved experimentally.     

High efficiency filtering using two-dimensional photonic crystal coupled cavity structures

Transmission spectra of coupled cavity structures (CCSs) in two-dimensional (2D) photonic crystals (PCs) are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain (FDTD) method, and the results show that within a very short coupling distance of about 3λ, where λ is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies.