太行山黄芪中黄芪多糖的提取工艺

采用碱性水提醇沉法进行黄芪多糖的提取,用蒽酮-浓硫酸比色法测定多糖的含量.通过改变黄芪的粒度,水浴比,水浴温度,提取次数,乙醇浓度及pH值等条件的研究,筛选出最佳提取工艺条件:于1:12的水浴比在70C水浴提取3次,乙醇浓度为90%,pH=10的条件下黄芪多糖的提取率最高,为19.2%.     

益母草多糖的抗氧化性

测定益母草多糖含量和研究其多糖的抗氧化性.利用水提醇沉法提取粗多糖,并利用Sevage法脱蛋白对其进行纯化;采用苯酚-硫酸法测定益母草多糖样品中纯多糖的含量并采用邻苯三酚自氧化法和水杨酸法分别研究益母草多糖清除O2-·和·OH的效果.益母草提取所得多糖样品中纯多糖含量达48.5％,益母草多糖具有较强的清除O2-·和·OH的作用.     

均匀设计法优化超声波辅助提取枸杞多糖的工艺

实验采用超声波辅助技术提取枸杞多糖,并通过均匀设计法研究了液料比、提取时间、提取温度和超声功率对枸杞多糖提取的影响.枸杞多糖超声提取的最佳工艺为:液料比21mL/g,提取时间27min,提取温度63℃,超声功率200W,在该条件下枸杞多糖得率为5.16％,且表现稳定.均匀设计法在优化枸杞多糖提取条件中应用效果良好.     

荚果蕨多糖的组成分析及其抗氧化活性

提取分离从陕西省宁陕县采集的荚果蕨根状茎中的多糖成分,采用高效液相色谱法分析单糖组成,应用羟自由基清除法评价其抗氧化作用.荚果蕨根状茎经超声辅助水提取、醇沉、脱蛋白和透析后得多糖,将多糖水解并用1-苯基-3-甲基-5-吡唑啉酮(PMP)衍生化后进行高效液相色谱分析;同时,测定荚果蕨多糖对羟自由基的清除效果.荚果蕨根状茎中多糖由葡萄糖、半乳糖、木糖3种单糖组成,摩尔比为3.50∶1.39∶1,其中葡萄糖的含量明显高于其他单糖含量;荚果蕨根状茎中多糖能有效对羟自由基的半数抑制浓度(IC50)为0.74mg/mL,具有较强的抗氧化作用,且呈浓度依赖关系.本实验方法简便灵敏,结果准确可靠,为综合开发利用荚果蕨提供科学依据.     

热水回流提取香椿叶多糖的工艺研究

研究热水回流提取香椿叶总多糖的工艺条件。单因素考察了原料粒度、提取温度、提取时间、料液比对香椿叶总多糖提取量的影响。以香椿叶总多糖提取量为考察指标,选用L9(34)试验设计对香椿叶总多糖的热水回流提取工艺条件进行优化,并验证最佳工艺条件、确定提取次数。其最佳工艺条件为:在原料粒度约为40目的条件下,提取温度为90℃,提取时间为3h,料液比为1∶25,提取次数为5次。在最佳参数组合下,每克香椿叶可提取总多糖为34.783mg。     

苯酚-硫酸法测定北芪菇多糖的含量

采用水提醇沉法从北芪菇中提取水溶性多糖,用Sevage法除蛋白,通过苯酚-硫酸比色法在490nm波长处测定多糖含量.在10-80μg·mL-1范围内,葡萄糖质量浓度与吸光度线性关系良好,相关系数r=0.9985,平均回收率为97.74％,相对标准偏差为2.36％（n=6）,北芪菇中多糖含量为5.45％％.方法快速、简单,稳定性好,可作为北芪菇多糖的常规检测方法.     

海参胶囊中海参多糖的提取方法

对海参胶囊中海参多糖进行提取纯化。分别探讨了酶解法、超声波提取方法;双氧水、活性炭脱色法及乙酸钾、三氯乙酸法除蛋白方法对海参多糖的得率的影响。确定最适提取条件:1g胶囊在胰蛋白酶加酶量为8000U/g,温度为37℃,pH 8.1,酶解3h后酶解完全;醇沉得到粗多糖后,经双氧水脱色、乙酸钾除蛋白。     

中药透皮剂的研究

透皮给药比口服和注射给药具有避免肝脏首过效应、避免胃肠道降解、避免皮肤损伤、释药速率稳定、血药浓度可控,毒副作用小,停、用药方便和给药频率低等优点,利于长期治疗。本实验中草药组成复方以水提醇沉法、回流法、浸制法制得浸膏,采用改良的Franz扩散装置,以离体鸡皮为屏障生理盐水为接受介质,用紫外分光光度法测定中药复方在不同条件下的吸光度,来判断其透皮效果。结果表明,回流法制得透皮剂浸膏的吸光度最大。回流法所制透皮剂渗透效果最佳,随着时间的延长,渗透效果不断加强,其透皮效果明显优于水提醇沉法和浸渍法;水提醇沉法和浸渍法所制透皮剂效果不显著。     

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℃.     

大蓟多糖提取分离及含量测定

用水提-醇沉法从大蓟中提取多糖,脱脂、去蛋白,经冷冻干燥后得到粗多糖。通过苯酚-硫酸法测定糖的含量,粗多糖得率为6.5%。再采用DEAE-纤维素离子交换柱层析进一步分离纯化,得到5个次级组分DJ1,DJ2,DJ3,DJ4和DJ5。其中得率最高的是DJ2组分,为8.06‰。     

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.