Determination of Matrine and Oxymatrine in Radix Sophorae Flavescentis by Resonance Rayleigh Scattering, Second-order Scattering and Frequency Doubling Scattering Technique

In 0.1 mol/L HCl medium, 12-tungstophosphoric（TP） acid reacted with matrine（Mat） and oxymatrine（Oxy） to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering（RRS）, second-order scattering（SOS） and frequency doubling scattering（FDS） appeared and their intensities were enhanced greatly. The maximum scattering wavelengths of RRS, SOS and FDS were located at 370, 670 and 390 nm, respectively. The in-crements of scattering intensity were directly proportional to the concentration of Mat and Oxy in a certain range. Based on this, the method for the determination of matrine and oxymatrine has been established. It has been applied to the determination of matrine and oxymatrine in samples of Radix sophorae flavescentis with satisfactory result. The reaction mechanism and reasons of RRS enhancement were discussed.

A Second-Order Method for the Electromagnetic Scattering from a Large Cavity

In this paper,we study the electromagnetic scattering from a two dimen- sional large rectangular open cavity embedded in an infinite ground plane,which is modelled by Helmholtz equations.By introducing nonlocal transparent boundary con- ditions,the problem in the open cavity is reduced to a bounded domain problem.A hypersingular integral operator and a weakly singular integral operator are involved in the TM and TE cases,respectively.A new second-order Toeplitz type approximation and a second-order finite difference scheme are proposed for approximating the hyper- singular integral operator on the aperture and the Helmholtz in the cavity,respectively. The existence and uniqueness of the numerical solution in the TE case are established for arbitrary wavenumbers.A fast algorithm for the second-order approximation is pro- posed for solving the cavity model with layered media.Numerical results show the second-order accuracy and efficiency of the fast algorithm.More important is that the algorithm is easy to implement as a preconditioner for cavity models with more general media.

Study of scattering from time-varying Gerstners sea surface using second-order small slope approximation

Backscattered fields from one-dimensional time-varying Gerstners sea surface are calculated utilising the secondorder small slope approximation. It is well known that spectral properties of the backscattered echoes relate to the velocity of the small elementary scatterers on sea surface profiles. Therefore, modeling Doppler spectra from the ocean requires an accurate description of the sea surface motion. The profile of nonlinear Gerstners sea surface shows verticalskewness of sea waves, it is sharper at the crest and flatter at the trough than linear waves, and its maximum slope position is closer to the crest than to the trough. Furthermore, the horizontal component of the small elementary scatterers orbit velocity on the sea surface, which yields noticeable influence on Doppler spectra, can be obtained conveniently by Gerstners sea surface model. In this study the characteristics of Doppler spectra of backscattered fields from time-varying Gerstners sea surface are investigated and the dependences of the Doppler frequency and the Doppler bandwidth on the parameters, such as the wind speed, the radar frequency, the incident angle, etc. are discussed. It is shown that the Doppler bandwidth of microwave scattered fields from Gerstners sea surface is considerably broadened. For the case of high frequency backscattered fields, the values of the higher-order spectrum peaks are larger than those obtained by linear sea surface.

Second-order Nonlinearities of CdS Nanoparticles Studied by Hyper-Rayleigh Scattering Technique

A series of CdS nanoparticles with different surfaces were prepared by colloidal chemical method and reverse micelle method. Their second-order nonlinear optical (NLO) properties were experimentally studied in solution by newly developed hyper-Rayleigh scattering (HRS) technique. The results show that 'per particle' first-order hyperpolarizability beta values are sensitive To the synthetic method and the surface chemical modification.

Resonance Rayleigh Scattering and Resonance Nonlinear Scattering Methods for Determination of Methylene Blue with 12-Tungstophosphoric Acid

In a pH=0.65―1.5 NaAc-HCl medium, methylene blue（MB） reacts with 12-tungstophosphoric acid （TPA） by virtue of electrostatic attraction and hydrophobic force to form a 3：2 ion-association complex. As a result, the intensities of resonance Rayleigh scattering（RRS）, second-order scattering（SOS） and frequency doubling scatte- ring（FDS） are enhanced greatly. The maximum scattering wavelengths of RRS, SOS and FDS are located at 316, 647 and 311 nm. The increments of scattering intensity（△I） are directly proportional to the concentration of MB in a certain range. The methods exhibited high sensitivity, and the detection limits（3s） for MB are 2.3 ng/mL（RRS method）, 5.6 ng/mL（SOS method） and 6.4 ng/mL（FDS method）, respectively. The effects of coexisting substances have been examined, and the results indicate that the methods have good selectivity. Based on the above researches, a new spectral method for the determination of trace amounts of MB has been developed. It can be applied to the determination of MB in human serum, and the recoveries are 97.5%―105.0%. The results are in good agreement with those obtained by the pharmacopoeia method. In this work, the optimum conditions of the reaction and the influencing factors were investigated. In addition, the reaction mechanism and the reasons of the enhancement of resonance light scattering were discussed.

Seismic inversion with generalized Radon transform based on local second-order approximation of scattered field in acoustic media

Sound velocity inversion problem based on scattering theory is formulated in terms of a nonlinear integral equation associated with scattered field. Because of its nonlinearity, in practice, linearization algorisms （Born/ single scattering approximation） are widely used to obtain an approximate inversion solution. However, the linearized strategy is not congruent with seismic wave propagation mechanics in strong perturbation （heterogeneous） medium. In order to partially dispense with the weak perturbation assumption of the Born approximation, we present a new approach from the following two steps： firstly, to handle the forward scattering by taking into account the second- order Born approximation, which is related to generalized Radon transform （GRT） about quadratic scattering poten- tial; then to derive a nonlinear quadratic inversion formula by resorting to inverse GRT. In our formulation, there is a significant quadratic term regarding scattering potential, and it can provide an amplitude correction for inversion results beyond standard linear inversion. The numerical experiments demonstrate that the linear single scattering inversion is only good in amplitude for relative velocity perturbation （3c/c0） of background media up to 10 %, andits inversion errors are unacceptable for the perturbation beyond 10 %. In contrast, the quadratic inversion can give more accurate amplitude-preserved recovery for the per- turbation up to 40 %. Our inversion scheme is able to manage double scattering effects by estimating a trans- mission factor from an integral over a small area, and therefore, only a small portion of computational time is added to the original linear migration/inversion process.

Study of second-order nonlinear hyperpolarisability of all-trans-β-carotene in solutions by linear spectroscopic technique

This paper demonstrates the second-order nonlinear hyperpolarisability γ of all-trans-β-carotene in different solvents by linear spectroscopic technique that is based on resonance Raman scattering and UV-VIS （Ultraviolet-visible） absorption spectroscopy. Owing to the two-level model well describing the link that exists between the resonance Raman scattering and stimulated Raman scattering, the stimulated Raman polarisability αR can be calculated through the two-photon resonance system. The value of γ of all-trans-β-carotene in carbon bisulfide solution is 6.435×10^-33 esu （1 esu of resistance = 8.98755×10^11Ω） that is close to the true value, because the solution of all-trans-β-carotene in carbon bisulfide satisfies the rigid resonance Raman scattering condition. This method is expected to be worthy of applications to measure the second-order nonlinear hyperpolaxisability of a conjugate organic molecule.

Lensless ghost imaging through the strongly scattering medium

Lensless ghost imaging has attracted much interest in recent years due to its profound physics and potential applications. In this paper we report studies of the robust properties of the lensless ghost imaging system with a pseudo-thermal light source in a strongly scattering medium. The effects of the positions of the strong medium on the ghost imaging are investigated. In the lensless ghost imaging system, a pseudo-thermal light is split into two correlated beams by a beam splitter. One beam goes to a charge-coupled detector camera, labeled as CCD2. The other beam goes to an object and then is collected in another charge-coupled detector camera, labeled as CCD1, which serves as a bucket detector. When the strong medium, a pane of ground glass disk, is placed between the object and CCD1, the bucket detector, the quality of ghost imaging is barely affected and a good image could still be obtained. The quality of the ghost imaging can also be maintained, even when the ground glass is rotating, which is the strongest scattering medium so far. However, when the strongly scattering medium is present in the optical path from the light source to CCD2 or the object, the lensless ghost imaging system hardly retrieves the image of the object. A theoretical analysis in terms of the second-order correlation function is also provided.

Size Dependence of First-order Hyperpolarizability of CdS Nanoparticles Studied by Hyper-Rayleigh Scattering

The second-order optical nonlinearity of CdS nanoparticles with different diameters of 28.0, 30.0, 31.5, 50.0, and 91.0 A was studied by hyper-Rayleigh scattering technique. Results show that the first-order hyperpolarizability P value per CdS partiele decreases as size is reduced to diameter of 31.5 A; however, as CdS size further decreases, this trend is reversed and (J value increases. Substantially, the normalized P value per CdS formula unit, β0, exhibits systematic enhancement with decreasing size. This phenomenon is interpreted in terms of a so-called surfaee contribution mechanism.

Study on the interaction between palladium(II)-chlorpromazine hydrochloride and sodium tungstate by the resonance Rayleigh scattering, second-order scattering and frequency doubling scattering spectra and its analytical application

The interaction between palladium(II)-chlorpromazine hydrochloride and sodium tungstate was investigated by ultravioletvisible absorption,resonance Rayleigh scattering(RRS),second-order scattering(SOS)and frequency doubling scattering (FDS)spectroscopy.In pH 5.3 Britton-Robinson(BR)buffer medium,chlorpromazine hydrochloride(CPZ)reacted with Pd(II) to form 2:1 cationic chelate,which further reacted with Na2WO4 to form a 1:1 ternary ion-association complex ([Pd(CPZ)2]·WO4).As a result,the signal intensities of RRS,SOS and FDS were enhanced greatly,and the enhancements of scattering were proportional to the CPZ concentration in a certain range.Their maximum wavelengths were located at 310 nm, 570 nm and 391 nm,respectively and the detection limits(3)were 1.6 ng/mL(RRS method),3.2 ng/mL(SOS method)and 5.6 ng/mL(FDS method).The optimum reaction conditions,the influences of coexisting substances and analytical application were mainly investigated by RRS method due to its highest sensitivity.A highly sensitive,simple,rapid and new method had been proposed to determine CPZ in the pharmaceutical form and residue of CPZ in pork.In addition,the Gibbs free energy change(△Gf)of ion-association reaction was computed by using B3LYP/3-21g*/LanL2dz method.The formation of ion-association and the reasons for the enhancement of RRS were also discussed.

SCATTERING OF A GRAZING LONGITUDINAL WAVE PULSE BY A RIBBON-TYPE CRACK—THE SECOND-ORDER APPROXIMATE SOLUTION

Scattering of an incident grazing longitudinal ultrasonic wave pulse by a traction - free ribbon - type crack in solid is theoretically analyzed. An exact series solution of the scattered field is obtained by iteration. Each term of the series corresponds roughly to one of the rescattering processes by the respective crack tips. The first two terms, which combine to form the second order approximate solution, are discussed in detail. This 2nd - order solution includes scattered cylindrical longitudinal waves, cylindrical shear waves , head waves and surface waves on the crack surfaces, and it gives good description of the early - time wave field.

(SO+2O)/Cu(100)NEXAFS谱反常共振峰结构的研究

利用多重散射团簇 (MSC)方法对 (SO + 2O) /Cu( 1 0 0 )的硫 1s和氧 1s近边X射线吸收精细结构 (NEXAFS)谱的理论分析和利用DV Xα 方法对该系统的团簇电子结构研究 ,揭示了该系统NEXAFS谱反常共振结构的物理起源 .SO和衬底的相互作用使π 分裂为二个轨道方向相互垂直的π 与衬底的耦合态 .NEXAFS谱的反常共振结构对应于 1s电子跃迁到这二个π

Effects of second-order dispersion of ultrashort laser pulse on stimulated Raman scattering

The influence of second-order dispersion(SOD)on stimulated Raman scattering(SRS)in the interaction of an ultrashort intense laser with plasma was investigated.More significant backward SRS was observed with the increase of the absolute value of SOD(|ψ2|).The integrated intensity of the scattered light is positively correlated to the driver laser pulse duration.Accompanied by the side SRS,filaments with different angles along the laser propagation direction were observed in the transverse shadowgraph.A model incorporating Landau damping and above-threshold ionization was developed to explain the SOD-dependent angular distribution of the filaments.

Study on the resonance Rayleigh scattering spectra and resonance non-linear spectra of congo red-amikacin system and its analytical application

The interaction between congo red (CR) and amikacin (AMK) was studied by resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS) and second-order scattering (SOS) combining with absorption spectrum. In a weak acidic medium, CR combined with AMK to form an ion association complex with the composition ratio of 1∶1 by electrostatic interaction, hydrophobicity and charge transferring effect. As a result, the new spectra of RRS, FDS, and SOS appeared and their intensities were enhanced greatly. The maximum wavelengths of RRS, FDS and SOS were located at 563 nm, 475 nm and 940 nm, and the scattering intensities were proportional to the concentration of AMK. These three methods have very high sensitivities, and the detection limits were 4.0 ng·mL?1 for RRS, 3.6 ng·mL?1 for FDS and 1.9 ng·mL?1 for SOS, respectively. At the same time, the methods have better selectivity. A new method for the determination of trace amounts of AMK with congo red by resonance scattering technique has been developed. The recovery for the determination of AMK in blood serum and urine sample was between 95.5% and 105.5%. In this study, the properties, such as enthalpy of formation, charge distribution and mean polarizability, were calculated by AM1 quantum chemistry method. In addition, the reaction mechanism and the reasons for the enhancement of scattering spectra were discussed.

水色遥感的精确Rayleigh散射算法研究

偏振问题是卫星水色遥感需要解决的一个重要问题。通过对带偏振的辐射传输方程进行求解得到精确的Rayleigh散射计算结果，便可以对水色遥感器进行偏振修正.本研究将矢量辐射传输方程进行傅立叶展开，得到与方位角独立的矢量辐射传输方程，利用逐次散射法对其进行求解？本文给出了HY-1卫星上水色遥感器COCTS在不同观测角厦和不同风速情况下的精确Rayleigh散射结果。

阴离子表面活性剂-健那绿体系的二级散射光谱及其分析应用

建立了二级散射光谱法测定阴离子表面活性剂的新方法。研究了阴离子表面活性剂SDBS与健那绿离子缔合物的二级散射和"反二级散射"光谱。结果表明:当λem=340nm,λex=680nm时,在0～50μg mL质量浓度范围内,ΔIFDS与溶液中物质的质量浓度成正比,线性相关系数为0.9988,检出限为17.4ng mL。

曙红Y瑞利散射、二级散射及倍频散射法测定痕量铝

试验表明:在pH 5.0的乙酸盐缓冲介质中,铝(Ⅲ)与曙红Y反应体系的瑞利散射(RRS)、二级散射(SOS)和倍频散射(FDS)均有增敏现象。分别选择λex=λem=598nm(RRS),λex=330nm、λem=660nm(SOS)和λex=604nm、λem=302nm(FDS)作为3种散射强度的测定波长。试验时,选择曙红Y溶液的浓度为5.0×10-5 mol·L-1;在室温反应3min。结果表明:上述3种散射光谱法所测得的ΔIRRS,ΔISOS和ΔIFDS均与铝(Ⅲ)的质量浓度在一定范围内呈线性关系,其检出限(3s)依次为7.5,4.0,8.0μg·L-1。二级散射法的线性范围较宽(0.012~1.5mg·L-1),且检出限最低。用此法分析了人发和茶叶样品,所得结果与原子吸收光谱法的结果相符。用标准加入法进行回收试验,回收率在96.3%~105%之间,测定值的相对标准偏差(n=7)均小于5%。

二维非均匀散射信道改进模型

提出了一种基于谐波信号叠加的二维非均匀散射信道改进模型,分析并给出了基于信号入射角概率面积等分的参数计算方法。该方案可完成任意接收信号入射角一维概率分布已知的单径散射信道仿真,且易于采用分段仿真的思想提高各阶统计参量的性能或实现多径信道仿真。分析和仿真结果表明,新模型的信道自相关函数、多普勒功率谱等二阶统计参量与理论模型十分接近,且优于其他常见模型。

近似解析求解Woods-Saxon势场Klein-Gordon方程

利用超几何函数方法对Pekeris近似中心项的变形Woods-Saxon势任意l态Klein-Gordon方程的束缚态和散射态进行近似解析求解,推导出径向波函数和束缚态特征值方程,得到了散射态相移公式,并通过对散射振幅在极点解析性质的研究得到了束缚态能级,最后讨论态的特例。