火焰原子吸收法测定夏枯草、桑叶、野菊花中十种微量元素

湿法消化样品 ,火焰原子吸收法测定三种草药中的 Mg、Ca、Zn、Mn、Co、Ni、Pb、Cd、Fe、Cu等 10种微量元素。回收率分别为 97.7%— 10 1.5 % ;96 .0 %— 10 5 .1% ;97.1%— 10 3.6 % ,相对标准偏差为 1.6 %—4 .5 % ;1.7%— 4 .7% ;1.7%— 4 .6 %。结果表明 ,三种草药均含有丰富的微量元素如 Mg、Ca、Zn、Mn、Fe、Cu等 ;为原料的开发和应用提供有效数据。     

UV-改进目标因子分析法对混用除草剂4组分的同时测定

组分间存在交互作用的 4种除草剂组成的混合样采用UV 目标因子分析法进行同时测定 ,结果相对误差较大。同样实验条件下 ,引入一个非零截距因子 ,进行改进目标因子分析 ,结果令人满意。改进目标因子分析 UV法 ,不经分离对 4种除草剂同时测定的回收率分别为百草枯 99 4 7%～ 10 2 0 2 %、氰草津 98 93%～ 10 2 75 %、异丙甲草胺 98 13%～ 10 2 6 5 %、莠去津 97 4 2 %～ 10 3 2 0 %。4种除草剂回收率的标准偏差分别为百草枯 1 16 %、氰草津 1 84 %、异丙甲草胺 1 84 %、莠去津 2 5 5 %。实验结果表明 ,改进目标因子分析方法对此类混用除草剂的同时测定具有较高的准确度和精密度。     

珍珠梅不同部位总黄酮含量的测定

用分光光度法测定了山高粱叶、茎、果各部位总黄酮的含量分别为 :4 .5 72 %、4 .96 0 %、1.2 33% ;平均回收率分别为 :10 1.0 %、10 0 .1%、10 1.5 % ;相对标准偏差分别为 :1.0 0 %、0 .10 8%、1.4 6 %。     

石墨炉原子吸收光谱法测定人血清中微量锰

采用石墨炉原子吸收光谱法测定人血清中微量锰 ,回收率为 10 5 .0 % ,检出限为 7.7× 10 -10 g/ m L,相对标准偏差为 6 .5 16 %。本方法简单、快速和准确 ,已用于血中微量锰的测定 ,结果令人满意。     

添加剂对褐煤薄层微波干燥特性影响

本文对褐煤薄层微波干燥动力学特性进行实验研究,分析微波功率及添加剂(剂量分别为5%和10%氯化钠、剂量5%碳酸钠)对褐煤干燥动力学特性的影响规律。结果表明:添加剂对褐煤微波干燥特性具有显著性影响。与原褐煤相比,功率为119 W时添加剂效果最为显著,添加5%氯化钠、5%碳酸钠和10%氯化钠后,褐煤平均干燥速率分别增大3%、20%和36%。纯褐煤、褐煤/5%氯化钠、褐煤/5%碳酸钠和褐煤/10%氯化钠第一降速段活化能分别为17.17W·g~(-1)、14.60 W·g~(-1)、13.48 W·g~(-1)和13.33 W·g~(-1);第二降速段活化能分别为15.23 W·g~(-1)、10.51 W·g~(-1)、10.12W.g~(-1)和9.32 W.g~(-1)。添加剂加入均使得褐煤两个降速段活化能降低,与5%剂量氯化钠相比,添加10%氯化钠后褐煤的活化能有所降低;碳酸钠可更好的改善褐煤薄层微波干燥特性。     

ICP-AES测定铂金饰品抛光灰中铂、钯、金和银

提出一种 ICP- AES快速测定铂金饰品抛光灰中铂、钯、金、银的分析方法。 5 g样品经灰化处理后 ,王水提取 ,直接测定 ,该方法的检出限 Pt、Pd、Au、Ag分别为 4 6 .5、4 2 .3、10 .4和 5 .1ng·m L-1。回收率为94 .2 %— 10 3.5 %之间。相对标准偏差为 2 .8%— 4 .4 %。     

不同醇对猪心线粒体F_1-ATPase和H~+-ATPase复合体构象的影响——圆二色性光谱研究

本文测定了ATPase复合体和F_1-ATPase在低浓度甲、乙、正丙、异丙、叔丁醇中的远紫外圆二色(CD)谱。结果表明:5—20%甲醇、5—10%乙醇、5%正丙醇、5—10%异丙醇和叔丁醇使F_1—ATPase的CD谱双负峰变大,F_1的α-螺旋量增加,20%乙醇,10—20%正丙醇、20%异丙醇则使F_1的CD双负峰明显变小,F_1的α-螺旋量显著减少。而外加5—20%的醇对ATPase复合体的远紫外CD谱影响不大,计算出的α-螺旋量也无明显变化。显然,与游离的F_1-ATPase相比,ATPase复合体中疏水蛋白(F_0)及部分磷脂的存在,使其构象呈现了醇稳定性。     

ICP-AES同时测定食用菌中钙、镁、铁、锰、铜和锌

微波消化、ICP- AES法同时测定食用菌中的钙、镁、铁、锰、铜和锌。 6种元素的加标回收率为90 .5 %— 10 3% ,RSD为 0 .6 4%— 3.6 % (n=10 )。操作方便 ,分析速度快 ,结果准确     

化妆品中铅、镉含量的测定

原子吸收光谱法测定了化妆品中的铅和镉 ,铅和镉分别在 0 .5 0— 10 .0 0 μg·m L-1和 0 .2 0— 8.0 0 μg·m L-1范围内有良好的线性关系 ,相关系数分别为 r=0 .9989和 r=0 .9997;标准偏差分别为 RSD≤1.6 7%和 RSD≤ 4 .71% ;标准加入法测定铅和镉的回收率分别为 93.5 %— 10 6 .0 %和 94 .0 %— 10 5 .5 %。方法简单 ,结果准确。     

氢化物原子荧光法测定药用动物角中的微量砷和汞

以HNO3 HClO4 回流消解样品 ,采用氢化物发生无色散原子荧光光谱法测定青藏高原药用动物角中的微量元素砷和汞。方法简便、快速、灵敏、准确。在实验条件下 ,2 6种共存元素其含量低于允许存在量 ,对测定无影响。检出限As 1 5ng·mL-1,Hg 0 80ng·mL-1;RSD(n =11)As 1 2 %～ 2 3% ,Hg 2 5 %～4 7% ;标准回收率As 98 9%～ 10 3 8% ,Hg 95 4%～ 10 5 0 %。     

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.