梅州仙人草中微量元素含量的分析

采用微波消解-电感耦合等离子体-原子发射光谱法测定了梅州仙人草中K、Ca、Na、Mg、Cu、Zn、Mn、Fe共8种元素的含量.结果表明:仙人草中K、Ca、Mg、Fe等人体必需微量元素含量非常丰富.该方法的加标回收率在96.0%-106.7%之间,相对标准偏差小于3%,具有较好的准确度和精密度.     

FAAS法测定苦杏仁和甜杏仁中的13种金属元素

采用硝酸、高氯酸(V/V=4/1)常压微沸条件下消解苦杏仁和甜杏仁样品,火焰原子吸收法测定苦杏仁和甜杏仁中的金属元素:Mn、Ca、K、Mg、Na、Zn、Cu、Fe、Co、Cd、Ni、Pb、Cr的含量,研究了测定不同元素仪器的最佳工作条件、方法的准确度和精密度.结果表明:苦杏仁中Mn、Ca、K、Mg、Na、Zn、Cu、Fe、Co、Cd、Ni和Pb的含量分别为11.756,1614.167,5153.191,238.478,97.668,274.836,16.844,546.316,9.952,3.474,5.979,2.143μg·g-1Cr未检出,方法回收率(n=9)在97.32%-102.57%之间,RSD(n=9)在0.14%-2.22%之间;甜杏仁中Mn、Ca、K、Mg、Ni、Zn、Cu、Fe、Co、Cd、Ni和Pb的含量分别为6.622,1937.503,8663.824,216.956,257.546,77.961,12.483,372.183,7.990,3.666,2.268,3.214μg·g-1Cr未检出,方法回收率(n=9)在97.23%-102.43%之间,RSD(n=9)在0.47%-2.14%之间.该法快速,简单,准确度和精密度均较高,能达到分析要求.     

ICP-AES测定自制风味红枣豆浆的营养元素

通过正交试验设计实验方案,以方差分析优化实验条件制备得到了风味独特的红枣豆浆。采用ICP-AES测定自制红枣豆浆的Ca、Zn、Fe、Mn、Mg、Cu和K7种营养元素。该法简单、快速、灵敏度高,准确性好。回收率在96.9%—100.5%之间,相对标准偏差小于2.02%。实验结果表明:自制红枣豆浆中K、Ca、Mg、Fe、Zn含量较为丰富,风味独特、品质较好。     

微波消解-火焰原子吸收光谱法测定2种不同来源重楼药材中的金属元素含量

采用微波消解-火焰原子吸收光谱法测定滇重楼和华重楼中Ca、Mg、K、Fe、Zn、Cu、Mn等7种金属元素的含量。结果表明,2种药材中金属元素的含量存在差异,其中滇重楼中宏量元素Ca、K、Mg,以及微量元素Cu的含量高于华重楼;而华重楼中微量元素Fe、Zn、Mn的含量高于滇重楼。实验的相关系数r≥0.9898,测定值的RSD在0.38%—1.70%之间,方法稳定可靠,其结果为进一步开发利用重楼药材资源提供了依据。     

陕北红枣中微量元素含量测定及聚类分析

采用火焰原子吸收光谱法,测定了6种红枣中6种微量元素的含量.测定结果表明,红枣中微量元素含量丰富,其含量顺序由高到低为Ca、Mg、Fe、Zn、Mn和Cu.并对6种红枣作了聚类分析,比较分析了6种红枣之间的相关性,这对于发挥红枣的药用价值具有重要意义.     

维药“比也”中总黄酮及微量元素含量的分析

用紫外可见分光光度法测定维药"比也"(榅桲)中的总黄酮含量,并用火焰原子吸收光谱法测定了K,Na,Ca,Fe,Cu,Co,Zn,Mn,Mg等9种元素含量.测定结果表明:"比也"(榅桲)中总黄酮量为3.87%,平均回收率为97.1%,RSD值为2.6%,并含有丰富的人体必需的微量元素,其中Na,K,Ca,Mg的含量更显著.微量元素测定方法的回收率在95.2%-104.1%之间,RSD值在0.42%-2.2%之间.通过本实验为榅桲的进一步研究和综合开发利用提供了新的科学依据.     

FAAS测定昙花中的7种金属元素

采用火焰原子吸收光谱法对昙花花和茎中K、Mg、Ca、Fe、Zn、Mn、Cu 7种金属元素的含量进行分析测定。结果显示昙花含有丰富的Fe、Zn、Mn、Cu微量元素。花中钾含量高达69763.61μg.g-1,约为茎的两倍。花中Mg、Fe、Zn、Cu的含量也高于茎,而花的Ca、Mn含量明显低于茎。昙花样品的加标回收率为93.8%—104.3%,相对标准偏差RSD≤3.67%,实验结果令人满意。     

控温湿法消解-火焰原子吸收光谱法测定苹果果皮和果肉中的微量元素

运用控温湿法消解-原子吸收光谱法同时测定了苹果果皮和果肉中Fe、Cu、Zn、Mn、Ca、Mg、Na和K8种微量元素的含量。方法的相对标准偏差≤1.17%,回收率介于93.8%—110.0%之间。结果表明,苹果果皮和果肉中Fe、Ca、Mn、Mg、K和Zn等人体必须的生命元素含量较高,各元素的含量均有差异。本试验为苹果的进一步研究提供了新的科学依据。     

微波消解-FAAS测定萝卜和萝卜缨中的微量元素

采用HNO3消解体系程序升温微波消解制样,应用火焰原子吸收法测定萝卜和萝卜缨中的Na、K、Ca、Mg、Fe、Mn、Zn、Cu共8种微量元素的含量.结果表明:萝卜和萝卜缨中富含人体必需的Na、K、Mg、Fe、Ca等微量元素,萝卜和萝卜缨之间微量元素含量有一定差异,其中K、Mg、Cu、Fe的含量两者差异不大,Ca、Zn和Mn在萝卜缨中的含量分别是萝卜中的3.33、3.28倍和1.75倍,Na在萝卜中的含量是萝卜缨中的1.14倍.方法的加标回收率为96.2％-105.5％,相对标准偏差(RSD)≤3.57％.方法简单快速、干扰少、精密度高、环境污染少,适合常规分析.     

原子吸收光谱测定刺五加中金属元素的含量

用原子吸收光谱法测定了刺五加根、茎、叶中Ca、Cu、Mg、Fe、Zn、K、Mn、Na等8种矿物质元素的含量,并对其结果进行了分析比较,以此研究了这8种金属元素在刺五加体内的分布。结果显示：各元素在实验范围内,线性关系良好,加标回收率在99%—109.6%之间,相对标准偏差为0.2%—1.8%。刺五加中不同部位的这8种元素间存在显著差异,根中Ca〉Mg〉K〉Fe〉Na〉Mn〉Zn〉Cu,其叶中的含量以K为高,而且各部位均有较高的Ca、Cu、Mg、Fe、Zn、K、Mn、Na。从微量元素的角度分析,刺五加的根、茎、叶均有一定的应用价值。     

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.     

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.     

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.