鱼腥草中总黄酮的微波辅助萃取研究

对鱼腥草进行微波处理,考察微波对鱼腥草中总黄酮提取的影响.以鱼腥草中总黄酮的提取量为指标,考察微波功率、微波作用时间、溶剂用量、鱼腥草粒度、水浸泡时间等因素的影响.鱼腥草中总黄酮提取的最佳工艺条件:鱼腥草用微波功率640W、间歇作用时间5min、固液比1∶40、粒度为细粉、浸泡时间为60min.     

微波-超声波辅助提取枸杞中的多糖工艺

利用微波-超声波辅助提取枸杞中的多糖物质,采用正交试验法考察料液比、浸提温度、微波和超声波功率以及时间等对枸杞中多糖物质提取效率的影响,得到最佳提取工艺:料液比为1∶10(g/mL),微波提取温度为100℃,微波功率为300W,提取时间6min,超声处理时间20min,超声功率80W,温度为70℃.     

3种不同提取方法测定百癣夏塔热片中的总黄酮

采用索氏提取、超声提取、微波萃取对百癣夏塔热片中总黄酮进行提取.3种方法均采用20倍(mL/g)甲醇;其中索氏提取时间为6h;超声提取时间为1h;微波萃取辐射时间:10min;温度:100C.以芦丁为标准品,用分光光度法测定,波长为510nm,芦丁浓度与吸光度呈良好的线性关系(r=0.9999).微波萃取、索氏提取和超...     

碱溶酸沉-微波辅助萃取艾叶中总黄酮的工艺研究

结合碱溶酸沉法对艾叶进行微波处理,以艾叶中总黄酮的提取量为指标,考察微波功率、微波作用时间、溶剂用量、水浸泡时间等因素的影响。结果表明艾叶中总黄酮提取的最佳工艺条件为:用石灰水调pH值至8—9,加入3%的硼砂,溶剂用量为料液比1∶8(mL/g)、浸泡时间20min、微波功率640W、提取时间7min,然后在提取液中加入稀盐酸,调pH值至2—3进行沉降。     

响应面法优化微波萃取慈竹多糖的工艺

利用微波提取慈竹竹秆中多糖类物质.在提取温度、提取时间、液固比等单因素试验的基础上,采用响应面法研究微波提取的最佳工艺条件.结果表明,微波功率为600W时,微波提取最佳条件为:提取温度123℃、提取时间44min、液固比为41∶1(mL/g);在此工艺条件下,提取一次,慈竹竹秆多糖的得率为0.586％,而理论预测多糖得率是0.590％,实际得率达到理论预测值的99.32％.     

回归正交试验设计优化猪苓多糖的提取工艺

以猪苓为原料,通过二次回归正交试验优化了猪苓多糖的提取工艺条件.结果表明:影响猪苓多糖提取率的因素顺序为:提取温度＞料液比＞pH＞微波提取时间＞微波功率;最佳提取工艺条件为提取时间3min,温度70.0℃,料液比1∶24.7 (g/mL),pH 6.91,微波功率400W,猪苓多糖的提取率为2.86％.     

香椿叶总黄酮的微波提取工艺

用微波技术提取香椿叶中总黄酮,分光光度法测定总黄酮含量,并对香椿叶总黄酮的微波提取工艺进行了探讨.结果表明,在乙醇浓度为50%-70%的情况下,微波提取的影响因素顺序为微波功率>微波作用时间>料液比>乙醇浓度.香椿叶总黄酮的最佳提取工艺条件为乙醇浓度50%,料液比1:40(g/mL),微波作用时间9min,微波功率500W.总黄酮得率为4.285%.     

微波萃取-分光光度法研究关黄柏中小檗碱的提取

微波萃取是利用微波能来提高萃取率的-种新技术,用正交法优化微波萃取条件,与传统的酸碱法浸提小檗碱进行了对比研究,确定了微波萃取技术用于中药关黄柏中提取小檗碱的工艺条件.结果表明,使用微波萃取的优化条件为:80℃萃取温度,固液比为1:15,时间1.5min,传统溶剂法:萃取温度70℃,固液比为1:20,时间24h,与稀硫酸浸泡提取法相比,微波萃取工艺提取时间大大缩短,产量可提高30%,工艺操作简便、省时、节能,易于控制.     

红景天中原花青素的微波提取工艺

通过单因素试验分析了微波提取过程中乙醇浓度、微波功率、提取时间和温度对原花青素提取率的影响.在单因素试验基础上,采用厶(34)正交试验筛选最佳微波提取工艺,即乙醇浓度为80％,微波功率为100W,提取温度为70℃,提取时间为10min.其中乙醇浓度对提取效果影响最大.在最佳提取条件下,红景天中原花青素的提取率为14.01％.     

微波辅助提取刺梨中总黄酮的工艺参数优化

以刺梨果实为原料,对微波辅助提取刺梨中的总黄酮的工艺进行研究,采用单因素试验法对影响微波辅助提取刺梨果实中总黄酮的影响因素进行分析,利用正交试验优化提取总黄酮的工艺条件。研究表明,微波辅助提取刺梨总黄酮的最佳工艺条件为:料液比1:20(g/mL),乙醇浓度60%,微波萃取功率400W,微波辐射时间3min。最佳工艺条件下的总黄酮的提取率为1.39%。     

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.     

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.     

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.     

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.     

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.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.