傅里叶变换红外光谱与圆二色光谱表征磷脂酶D二级结构的比较

报道了傅里叶变换红外光谱与圆二色光谱光学信息表征蛋白质二级结构的比较,研究表明傅里叶变换红外光谱与圆二色光谱光学信息表征蛋白质二级结构时,要注意缓冲体系的选择,磷酸盐缓冲液比醋酸盐缓冲液更适合使用,利用FTIR与CD光谱信息表征蛋白质二级结构,两者的数据吻合较好。     

云南松松塔中两种新木脂素圆二色谱的密度泛函研究

采用梯度校正的密度泛函理论方法,计算了云南松松塔中分离的2种新木脂素的绝对结构为7S,8R的手性结构、电子吸收光谱、电子圆二色谱、红外振动光谱和振动圆二色谱,计算值与实验值相符. 分子轨道和振动模式分析,两种新木质素具有相似的手性光谱. 电荷密度转移对电子圆二色谱具有主要贡献;而振动圆二色谱主要源于分子骨架运动.     

云南松松塔中两种新木脂素圆二色谱的密度泛函研究

采用梯度校正的密度泛函理论方法,计算了云南松松塔中分离的2种新木脂素的绝对结构为7S,8R的手性结构、电子吸收光谱、电子圆二色谱、红外振动光谱和振动圆二色谱,计算值与实验值相符. 分子轨道和振动模式分析,两种新木质素具有相似的手性光谱. 电荷密度转移对电子圆二色谱具有主要贡献;而振动圆二色谱主要源于分子骨架运动.     

G-四链体结构及其应用的光谱学研究

G-四链体是指一种由富含G碱基核酸序列通过G平面的π—π堆积形成的一种特殊的核酸二级结构。本文介绍作者课题组利用光谱表征方法(紫外可见光吸收、圆二色、拉曼、核磁共振光谱等)在G-四链体结构研究领域的最新进展。同时,对本组利用这些光谱技术研究G-四链体DNA酶的相关工作也一并介绍。     

光谱颜色科学研究进展及其在中药领域中应用前景分析

综述了光谱颜色科学的研究进展,近年来常用的颜色模型及颜色测量仪器,归纳总结测色技术在农业、食品、工业、医药等领域的应用进展。探讨测色技术实现中药外观色泽量化的可能性,并分析其在中药领域中的应用前景,为实现中药无损在线的质量控制规范化研究提供示范。     

光谱法研究葛根素与牛血清白蛋白的相互作用

采用紫外、同步荧光和圆二色光谱法研究了葛根素（PUE）与牛血清白蛋白（BSA）的相互作用.紫外光谱表明,BSA在230nm和278nm处的吸收峰,随着葛根素浓度的增加而减小.同步荧光光谱表明,葛根素引起BSA中色氨酸残基所处微环境的疏水性降低.圆二色光谱表明,BSA在208nm和222nm处的负峰随着葛根素浓度的增加而增强,BSA中α-螺旋含量也随之增加.这表明葛根素与BSA的相互作用,可使蛋白质分子的疏水作用增强,导致BSA的肽链结构收缩,蛋白质的构象发生变化.     

光谱法研究人胞红蛋白与铜(Ⅱ)离子的相互作用

胞红蛋白(Cygb)是近期在脊椎动物中发现的一种球蛋白家族成员,具有典型珠蛋白的“3+3”式的α-螺旋三明治折叠结构。利用紫外可见吸收光谱、荧光光谱、同步荧光光谱及圆二色(CD)光谱法研究了Cu2+离子与Cygb的相互作用。结果表明,当Cu2+离子加入到Cygb溶液中后,Cygb在280 nm处的紫外吸收强度增大,说明Cu2+与Cygb发生了相互作用;Cu2+使Cygb的内源性荧光发生猝灭,其猝灭方式为静态猝灭。同步荧光光谱研究表明,Cu2+可使色氨酸和酪氨酸的微环境发生较小的改变,与酪氨酸相比Cu2+对Cygb的键合部位更接近于色氨酸。圆二色光谱研究表明,Cu2+对Cygb的二级结构未引起明显变化。     

应用SRCD和FTIR分析超高压处理对蘑菇多酚氧化酶二级结构的影响

应用同步辐射紫外真空圆二色光谱(SRCD)、傅里叶变换红外光谱(FTIR)和荧光光谱研究了超高压(HHP)处理对蘑菇多酚氧化酶(PPO)二级结构和三级结构的影响。HHP处理使蘑菇PPO的α-螺旋含量明显减少,二级结构发生改变。通过SRCD光谱和FTIR光谱分析得出的未处理或HHP处理蘑菇PPO的二级结构含量均存在一定的差异,这种差异可能是由于测量温度、酶液浓度和分析方法等多种因素造成的。荧光光谱表明,HHP处理后,蘑菇PPO溶液荧光光谱的强度降低,最大发射峰发生了红移,表明HHP处理改变了蘑菇PPO分子的三级结构。     

BSRF圆二色谱研究进展

圆二色（ＣＤ）谱是一种特殊的吸收谱，它对手性分子的构象十分敏感，因此它是最重要的光谱实验之一。北京同步辐射装置（ＢＳＲＦ）３Ｂ１Ｂ生物光谱实验站已经投入运行，它提供单色聚焦的同步辐射光，波长覆盖范围１７０ｎｍ～５００ｎｍ该站的主要设备是一台圆二色谱仪，用这台仪器成功地获取了活性生物样品～捕光色素（ＬｉｇｔＨａｒｖｅｓｔＣｈｌｏｒｏｐｈｙｌｌ）的ＣＤ谱，同时测得樟脑磺酸（ＣａｍｐｈｏｒＳｕｌｆｏｎｉ     

光谱法研究人胞红蛋白与铜(Ⅱ)离子的相互作用（英文）

胞红蛋白(Cygb)是近期在脊椎动物中发现的一种球蛋白家族成员,具有典型珠蛋白的"3+3"式的α-螺旋三明治折叠结构。利用紫外可见吸收光谱、荧光光谱、同步荧光光谱及圆二色(CD)光谱法研究了Cu~(2+)离子与Cygb的相互作用。结果表明,当Cu~(2+)离子加入到Cygb溶液中后,Cygb在280nm处的紫外吸收强度增大,说明Cu~(2+)与Cygb发生了相互作用;Cu~(2+)使Cygb的内源性荧光发生猝灭,其猝灭方式为静态猝灭。同步荧光光谱研究表明,Cu~(2+)可使色氨酸和酪氨酸的微环境发生较小的改变,与酪氨酸相比Cu~(2+)对Cygb的键合部位更接近于色氨酸。圆二色光谱研究表明,Cu~(2+)对Cygb的二级结构未引起明显变化。     

Enhanced and tunable circular dichroism in the visible waveband by coupling of the waveguide mode and local surface plasmon resonances in double-layer asymmetric metal grating

Circular dichroism (CD) has shown very interesting possibilities as a means to characterize the chiral signal of a chiral structure. Here, we theoretically demonstrated enhanced and tunable CD in the visible light regime using a composite structure consisting of a double-layer metal grating gaped by a dielectric waveguide layer. Based on the coupling of the waveguide modes and the localized plasmonic resonances, the CD could reach a maximum value as high as 0.52 at 635 nm, which is four times higher than the CD value obtained in a conventional double-layer grating without the waveguide coupling effect. Furthermore, the spectral positions of the enhanced CD bands could be easily tuned by controlling the structural parameters. The proposed hybrid double-grating and waveguide structures could have potential applications in chiral selective imaging, sensing and spectroscopy, especially where the transmission measurement is required.     

Preparation and Characterization of the Fluorescent Carbon Dots Derived from the Lithium‐Intercalated Graphite used for Cell Imaging

Zero‐dimensional fluorescent carbon dots (CDs) that are used as a cell‐imaging reagent are prepared by using a simple and effective route employing lithium‐intercalated graphite from lithium‐ion batteries as a carbon source. Under ultrasonic exfoliation, the interlayer space increases, while the layer distortion and remaining lithium of the lithium‐intercalated graphite are utilized to disrupt the graphitic structure and produce the CD suspension. Subsequently, after concentration and purification, the obtained colloidal CD suspension has a fluorescent yield of up to 1.2% and is therefore comparable to the CDs prepared in previous reports. These CD products are water‐soluble, nanosized (approximately 3.5 nm), and biocompatible and can easily enter into HeLa cells to act as a cell‐imaging reagent without any further functionalization. In addition, these CDs do not impose toxicity against HeLa cells and have high photostability with low photobleaching and demonstrate potential applications for bio‐labeling as well as solution state optoelectronics.     

Enhanced circular dichroism based on the dual-chiral metamaterial in terahertz regime

The obvious circular dichroism(CD) and optical activity can be obtained based on the chiral metamaterial due to the plasmon-enhanced effect, which is very attractive for future compact devices with enhanced capabilities of light manipulation. In this paper, we propose a dual-chiral metamaterial composed of bilayer asymmetric split ring resonators(ASRR)that are in mirror-symmetry shape. It is demonstrated that the CD can get enhancement in the terahertz regime. Moreover,the CD can be further improved by modulating the asymmetry of ASRR. The enhanced CD effect in the terahertz regime has great potential applications in sensing, biomedical imaging, and molecular recognition.     

Circular dichroism spectra of α -lactose molecular measured by terahertz time-domain spectroscopy

Researchers have long studied circular dichroism (CD) for its enormous prospects in life sciences. Many biomolecules have vibration modes in the terahertz region, and terahertz CD spectra are robust to detect biomolecular structures. However, few studies explore the terahertz CD spectra on even natural materials due to technical challenges in both fields. Here, we report a setup of home-built terahertz time-domain spectroscopy to measure the polarization states of terahertz waves. By carefully measuring the transmission Jones matrix, we obtain terahertz CD spectra of α -lactose tablets and D-glucose tablets. Our results show that the terahertz CD spectra are sensitive to vibrational motions in biochemical compounds, which will find wide applications in biosensing and biomedical diagnostics.     

Chaotic direct sequence spread spectrum for secure underwater acoustic communication

Direct sequence spread spectrum (DSSS) has been widely used in underwater acoustic (UWA) communications. In DSSS communications, spreading sequence’s period and chip rate are important characteristic parameters. However, these characteristic parameters may be detected in hostile environments due to the periodic nature of spreading sequence and their well-known construction process. In this paper, a novel chaotic direct sequence spread spectrum (CD3S) method is proposed for secure UWA communications. In the CD3S communications, chaotic sequences acting as encryption keys are used to encrypt the phases of transmitted signals. Consequently, the application of chaotic sequences disguises these obvious characteristic parameters of spread spectrum (SS) signals. It is difficult for unauthorized users to detect or intercept CD3S signal without knowledge of corresponding chaotic sequences. Hence, CD3S signal has a lower probability of detection and interception. Moreover, CD3S can achieve similar bit error ratio (BER) performance compared with DSSS in actual UWA communications. Also, the receivers that are suitable for DSSS communication can also be applied to CD3S communication. Numerical simulations demonstrate its excellent performance and potential applications in confidential UWA communications.     

光学非球面透镜在一些光电仪器中的应用

使用非球面零件能大大简化光电仪器的系统，减小仪器的尺寸和重量，因而它得到越来越广泛的应用，介绍了光学非球面透镜在光盘机等光电仪器中的应用。说明了这些仪器中使用非球面透镜的原因，对透镜像质的要求，以及制造非球面透镜的材料。     

Traceability of CDs/DVDs used as retrospective 222Rn detectors to reference STAR laboratory

The practical applications of the method for retrospective ²²²Rn measurements by home stored CDs/DVDs need a proper metrological assurance. The specific feature of this method, as compared to other methods for retrospective ²²²Rn measurements is the possibility for an individual a posteriori calibration of the used CD/DVD-detectors. This paper describes a procedure to ensure the traceability of this method to a reference STAR laboratory. A set of 7 groups of CDs/DVDs were exposed to 4 reference ²²²Rn exposure levels. After that they were treated in the etching laboratory as ”real” detectors and the ²²²Rn concentrations were determined by applying an individual a posteriori calibration, correction for high track density and correction for depth at which the alpha tracks were etched. The results from all 7 groups of exposed detectors demonstrated relative variation from the reference values in the interval 3.4–23.4%. The results provide evidence that the routine measurements by the CD/DVD method warrant measurements with a relative uncertainty better than 25% and therefore this method is acceptable for large-scale applications.     

Chromatic dispersion compensation techniques and characterization of fiber Bragg grating for dispersion compensation

Pulse spreading due to the dispersion causes the overlapping of the transmitted pulses at the receiver end known as inter symbol interference (ISI). The ISI thus limits transmission of high speed data. We are living in the age of bandwidth hungry and high speed applications, for which optical networks form the most important part because of its high bandwidth. In optical networks chromatic dispersion (CD) is one of the main obstacle in high speed transmission. Hence this CD is compensated by various approaches throughout the transmission system. A review of all the main approaches is presented in this paper. Characterization of fiber Bragg grating for dispersion compensation is done using the reflection spectrum and group delay response analysis.     

A numerical parameter study of chiral metamaterial based on complementary U-shaped structure in infrared region

In this paper, the optical properties of the chiral metamaterial (CMM) with complementary U-shaped structure assembly have been investigated numerically in infrared frequencies. Here, we systematically study the dependence of CMM's optical properties to the structural parameters. The giant optical activity, circular dichroism (CD), and high negative refraction can be obtained by properly selecting the parameters, respectively. CMMs will also lead to many applications in photonic devices due to their strong polarization effect and CD effect.     

Multifunction optical filter with a Michelson-Gires-Tournois interferometer for wavelength-division-multiplexed network system applications

We propose using a novel multifunction optical filter with a Michelson-Gires-Tournois interferometer (MGTI) for future smart wavelength-division-multiplexed network system applications. The MGTI filter is a typical Michelson interferometer in which one of its reflecting mirrors is replaced with a Gires-Tournois resonator. One unique feature of this device is that it can function as a channel-passing (CP), a channel-dropping (CD), or a wide-bandpass (BP) filter, depending on the interferometer arm-length difference. Other interesting features are that (1) the linewidths of both the CP and the CD filter are twice as narrow as that of a typical Fabry-Perot filter with similar parameters, (2) theoretical visibility is always unity regardless of the mirror reflectance value, and (3) the BP filter has an excellent boxlike response function. Numerical results showing these characteristics are presented.