响应面优化蒽酮-硫酸法测定水溶性沙棘叶多糖含量

采用水提醇沉法从沙棘叶中提取水溶性沙棘叶多糖(WPFH),通过响应面优化蒽酮-硫酸显色,用分光光度法测定沙棘叶水溶性多糖的总糖含量。通过单因素和响应面法确定了最佳蒽酮-硫酸显色条件:显色温度为100℃,蒽酮试剂的用量为3.54mL,显色时间为10.95min。测定波长620nm,葡萄糖质量浓度在6.67—160μg/mL范围内与吸光度呈良好的线性关系,r=0.9993。该方法简单可行,平均回收率为100.36%,RSD为2.75%。精制WPFH换算因子f为1.266。     

灵芝多糖含量的红外光谱预测模型研究

利用傅里叶变换红外光谱仪(FTIR)测定不同等级贵州灵芝的傅里叶变换红外光谱,选择最佳的敏感波段组合构造吸光度变量,分析了吸光度变量与灵芝多糖含量的相关性,建立灵芝多糖含量的红外光谱预测模型并进行检验。结果表明:不同等级灵芝的红外光谱图基本相似,峰形相同;所选定的吸光度变量与灵芝多糖含量之间显著相关,灵芝多糖含量的预测模型及其检验结果的拟合度均达到显著水平,这说明可用红外光谱法来预测灵芝多糖含量。     

玫瑰枝叶中可溶性多糖的含量测定

通过单因素试验研究了苯酚-硫酸法测定玫瑰枝叶可溶性多糖含量的最佳实验条件,即6％的苯酚溶液用量为1.0mL、浓硫酸用量为5.0mL,在室温下放置显色15min后于分光光度计488nm波长处测定吸光度.用此方法对生长季不同时期、不同生理状态(开花与未开花)下玫瑰枝、叶多糖含量进行了测定.试验结果显示:玫瑰叶片可溶性多糖含量高于枝条;开花植株的多糖含量高于未开花植株;在生长季不同时期玫瑰枝叶多糖含量呈现V形动态变化趋势.     

黑龙江膜荚黄芪多糖提取与含量测定

研究了水提醇沉法制备的黄芪多糖提取物,采用苯酚-硫酸比色法测定多糖的含量,在0.00-0.14mg/mL线性范围内具有良好的线性关系,本法的RSD为0.98%.回收率在94.8%-103.5%之间.测定黄芪多糖含量为4.3%.此方法显色快速,反应稳定性较好,准确度、精密度较高.     

黑龙江膜荚黄芪多糖及微量元素Fe、Zn、Cu和Mn的测定

采用水提醇沉法制备黄芪多糖提取物,苯酚-硫酸分光光度法测定多糖的含量,在0.00-0.14mg/mL线性范围内具有良好的线性关系,回收率在94.81%-103.50%.测定黄芪多糖含量为4.3%.采用校准曲线法,用空气-乙炔火焰原子吸收光谱法测定样品中Fe、Zn、Cu和Mn的含量,膜荚黄芪中微量元素含量较高.     

新疆锁阳多糖的提取及含量测定

采用分光光度法测定新疆锁阳多糖的含量,以葡萄糖为对照品,以蒽酮-浓硫酸为显色剂,在625nm处测定样品溶液的吸光度。在40.00—200.00μg/mL范围内,葡萄糖质量浓度与吸光度呈良好线性关系,相关系数r=0.9998,回收率在96.15%—102.85%之间,相对标准偏差RSD为2.814%（n=5）,新疆锁阳多糖含量为2.39%。本方法操作简单,灵敏度高,可作为锁阳多糖的含量测定方法。     

蒙成药敖西根多糖的提取及含量测定

本文用热水提取了蒙成药敖西根中水溶性多糖,并用硫酸-苯酚法在波长为490nm处测定敖西根中多糖的含量,求得其标准曲线的回归方程为A=0.0140C-0.1500,r=0.9992,粗多糖产率为14.28%,平均回收率为99.8%,RSD 0.86%,糖含量为89.2%.     

白灵菇多糖的提取及含量的测定

苯酚-硫酸分光光度法测定白灵菇中多糖含量。测定波长485nm,多糖换算因子f=1.59,在5.00—70.00μg/mL范围内吸光度与被测物含量呈良好的线性关系,相关系数r=0.9998,方法的回收率在96.66%—102.33%%之间,相对标准偏差RSD在2.01%—3.10%之间。测定结果表明,白灵菇中含有丰富的多糖。本法简便、准确、重现性好,可作为白灵菇多糖含量的测定方法。     

南瓜生长过程中多糖含量的测定

苯酚-硫酸分光光度法测定了南瓜中多糖含量。测定波长为485nm,多糖换算因子f=2.97,在5.00—70.00μg/mL范围内呈良好的线性关系,相关系数r=0.9998,方法的回收率在96.0%—101.7%之间,相对标准偏差RSD在2.07%—3.12%之间。结果表明,南瓜多糖在南瓜生长40天后几乎不再发生变化。本法简便、准确、重现性行好,可作为南瓜中多糖含量的测定方法。     

7种常见食用菌中多糖的提取和测定

采用热水提取、乙醇沉淀的方法从7种食用菌中提取出了水溶性多糖,采用蒽酮-硫酸法在波长620nm处进行了糖含量的测定,求得其校准曲线的回归方程为y=0.0094x+0.0057,相关系数r为0.9998。平均回收率为98.3%—102.7%,RSD为2.1%—3.2%。结果显示粗多糖的提取率为4.44%—16.75%,多糖含量为3.48%—6.91%。     

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.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

Propagation of Helmholtz-Gauss beams in weak turbulent atmosphere

Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored.     

An effective method for reducing speckle noise in digital holography

An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography.     

Influence of purity of HfO2 on reflectance of ultraviolet multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.     

Speech enhancement by array crosstalk resistant ANC and spectrum subtraction

Microphone array-based speech enhancement has great importance for speech communications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation.