柠檬酸钠与牛血清白蛋白的相互作用

用荧光光谱法研究了柠檬酸钠与牛血清白蛋白( BSA)的作用机制.实验表明,柠檬酸钠对BSA具有荧光猝灭作用,其猝灭方式为静态猝灭,并求出了猝灭常数、结合常数及结合位点数.     

头孢噻肟钠和氯霉素与牛血清白蛋白相互作用的荧光光谱分析

在pH=7.40 Tris-HCl缓冲溶液中,应用荧光光谱法分别研究了298,303,308 K时,头孢噻肟钠(CTX)、氯霉素(CHL)对牛血清白蛋白(BSA)荧光的猝灭反应.结果表明:药物与BSA的结合稳定常数Ka随温度增加而降低,两种药物对BSA的荧光猝灭皆为静态猝灭过程.标记竞争实验表明CTX、CHL在BSA中...     

锌离子与牛血清白蛋白相互作用的研究

用荧光光谱法研究了锌离子(Zn2+)与牛血清白蛋白(BSA)的作用机制.实验表明,Zn2+对BSA具有荧光猝灭作用,其猝灭方式为静态猝灭.求出了猝灭常数、结合常数及结合位点数.利用同步荧光光谱研究了Zn2+对BSA分子荧光光谱的影响.     

荧光法研究可可碱与牛血清白蛋白的相互作用

采用荧光光谱法研究了可可碱这种生物碱药物与牛血清白蛋白(BSA)分子间的相互结合反应。测定了可可碱与BSA反应的结合平衡常数K和结合位点数n,并用同步荧光光谱技术考察了可可碱对牛血清白蛋白构象的影响。证实了可可碱药物与牛血清白蛋白的相互结合作用为单一的静态猝灭过程,可可碱的加入对牛血清白蛋白的构象有影响。     

L-半胱氨酸修饰的金纳米粒子与牛血清白蛋白相互作用的荧光光谱研究

采用荧光猝灭光谱和同步荧光光谱研究了L-半胱氨酸修饰的金纳米粒子(Cys-GNPs)与牛血清白蛋白(BSA)间的相互作用。根据荧光猝灭相关方程计算了Cys-GNPs与BSA相互作用的结合常数和结合位点数,探讨了其荧光猝灭机制为静态猝灭,并且根据热力学参数确定了二者间的作用力类型,推断出Cys-GNPs和BSA间主要靠疏水作用力结合。同步荧光光谱表明,二者的相互作用没有导致牛血清白蛋白的构象及色氨酸残基的微环境发生明显变化。     

番茄红素与牛血清白蛋白的相互作用

采用荧光光谱法研究了番茄红素(Lycopene)与牛血清白蛋白(BSA)的相互作用关系。研究表明,番茄红素能使BSA在340nm(λem)处产生荧光猝灭,猝灭机理为静态猝灭。pH=7.4,温度为293K时,猝灭时表观结合常数KA为5.33×104L.mol-1,结合位点数n为0.6461,同时荧光猝灭最大速率常数Kq=2.76×1012L.mol-1.s-1。二者呈自发结合且主要作用力为氢键和范德华力,结合距离r与能量转移效率E分别为5.6nm和0.098,偏酸性或碱性的条件使番茄红素与BSA的结合常数增加。     

荧光光谱法研究黄芩苷与牛血清白蛋白的相互作用

在pH为7.40的T ris-HC l缓冲体系中,采用荧光光谱技术研究了黄芩苷与牛血清白蛋白（BSA）的相互作用。随着温度升高,黄芩苷与牛血清白蛋白的猝灭常数逐渐增大,表明黄芩苷对BSA的荧光猝灭为动态猝灭过程,由结合过程的热力学参数ΔH=51.708 kJ.m o-l 1〉0和ΔS=265.075J.m o-l 1.K-1〉0,推断黄芩苷与BSA之间主要靠疏水作用力相结合,生成自由能变（ΔG）为负值,表明黄芩苷与BSA的作用过程是一个自发过程;应用同步荧光光谱考察了黄芩苷对BSA构象的影响。     

番红花红T与牛血清白蛋白作用的光谱特性

用荧光光谱法研究了番红花红T与牛血清白蛋白(BSA)的结合反应.结果显示番红花红T对牛血清白蛋白的荧光有猝灭作用,其猝灭类型属于静态猝灭;得到了不同温度下的结合常数和结合位点数;利用Van't Hoff方程计算得到该猝灭反应的热力学参数,结果表明番红花红T主要以静电作用力与BSA相互作用;同步荧光光谱显示番红花红T对B...     

氨与牛血清白蛋白的相互作用

用荧光光谱法和紫外吸收光谱法研究了在生理pH值条件下氨与牛血清白蛋白(BSA)的相互作用,结果表明:氨对BSA的荧光有较强的猝灭作用,该猝灭属于同时具有动态猝灭和静态猝灭特征的联合猝灭,但以静态猝灭为主.根据猝灭结果求得了不同温度下氨与BSA相互作用的结合位点数、结合常数及反应热力学参数,并据此推测它们之间主要的相互作...     

芬布芬与牛血清白蛋白相互作用的荧光光谱检测

在模拟生理条件下,用荧光光谱法和紫外-可见吸收光谱法研究芬布芬(FBF)和牛血清白蛋白(BSA)结合反应的特征.研究表明:芬布芬与牛血清白蛋白形成复合物,从而猝灭牛血清白蛋白的内源性荧光,该过程为静态猝灭过程.根据Stem-V(o)lmer方程得出了不同温度下结合位点数和结合常数;根据F(0)rster非辐射能量转移理...     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

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.     

Research on beamforming method for dual-line array with space mismatch between the two line arrays

The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Retrieval of ultraviolet skylight radiances and O3 slant column densities from balloon-borne limb spectrometer

With a novel light-weight and absolutely calibrated ultraviolet （UV） spectrometer, UV skylight radiances and O3 slant column densities are measured by balloon-borne limb measurements in Xinjiang area, China. UV skylight radiances measured at the height of 31 km are compared with the results from Modtran in the wavelength range from 290 to 420 nm. O3 slant column densities are derived from radiance spectra in the Huggins bands （320 - 335 nm） using differential optical absorption spectroscopy method. And the parameter exhibits a good correlation with the same value simulated by radiative transfer model （Tracy）. The O3 profile simultaneously measured by an O3 sonde is used as input in Tracy calculations. The O3 sonde is launched on the same balloon.