微波消化-分光光度法测定烟草中的镁

研究了偶氮氯膦 - 与镁的显色反应 ,在 p H=10 .0硼砂 -氢氧化钠缓冲介质中 ,偶氮氯膦 - 与镁反应生成 1∶ 1稳定的络合物 ,λmax=6 10 nm,ε=2 .34× 10 4L· mol-1· cm-1。镁含量在 0— 15μg/ 2 5 m L范围内符合比耳定律 ,结合微波消化样品技术 ,建立了一种烟草样品中镁含量的测定方法 ,结果令人满意     

4-(2-羟基-4-硝基苯偶氮)-1-苯基-3-甲基吡唑啉酮光度法测定烟草中镁

研究了 4 - (2 -羟基 - 4-硝基苯偶氮 ) - 1-苯基 - 3-甲基吡唑啉酮 (HNAPMP)与镁的显色反应 ,在 p H=10的硼砂 -氢氧化钠缓冲介质中 ,HNAPMP与镁反应生成 2∶ 1稳定络合物 ,λmax=5 2 2 nm,ε=3.5 8× 10 4L·mol-1· cm-1。镁含量在 0— 2 0 μg/2 5 m L范围内符合比耳定律 ,方法用于烟草样品中镁含量的测定 ,结果令人满意     

绿茶和红茶中微量元素初级形态含量的研究

本文采用沸水浸泡法对茶叶的初级形态进行分离 ,原子吸收光谱法测定了绿茶和红茶初级形态中 8种微量元素含量 ,计算并讨论了微量元素初级形态分析参数 ,获得茶叶中微量元素初级形态的有关信息。结果表明 ,绿茶和红茶中 8种微量元素初级形态含量各有差异 ,初级形态分析参数自符合程度为87.2 0 %— 10 3.73% ,样品的回收率为 87.1%— 10 2 %。     

原子吸收光谱法测定强力枇杷露中微量镁和镉

原子吸收光谱法测定7个不同厂家所生产的强力枇杷露中镁和镉元素含量。结果表明,样品溶液吸光度与浓度之间存在线性关系,其相关系数均在0.9991—0.9998之间,精密度在5%左右,且在2h以内保持较好的稳定性,加样回收率在95.5%—104.2%之间。采用以上方法检测强力枇杷露中镁和镉元素的含量,方法灵敏,准确,可靠。     

原子吸收光谱法测定茶叶中钙

采用原子吸收分光光度法对国内一些常用茶叶中的钙进行了测定 ,结果表明 ,茶叶中的钙含量丰富 ,为 12 14— 2 874 mg/kg,饮茶对人体健康有益。但茶汤中的钙浸出量仅为 2 3— 10 6 mg/kg,浸出率约 1.0—7.0 %。     

MPT-AES同时测定航空润滑油中的铝、镁和铜

微波等离子体炬原子发射光谱法 (MPT- AES)测定未使用过的航空润滑油中铝、镁和铜含量。研究了微波功率、载气流量、工作气流量、氧屏蔽气流量、酸效应、共存离子等对元素发射强度的影响 ,优化了系统参数。铝、镁和铜的检出限分别为 15 .1ng/ m L、0 .2 8ng/ m L、2 .1ng/ m L,线性范围分别为 0 .0 5—80μg/ m L、0 .0 0 1— 5 0μg/ m L、0 .0 1— 12μg/ m L ,相对标准偏差均小于 3.7% ,回收率在 95 .6 %— 10 5 .3%之间。方法准确、快速、操作简便、维持费用低。     

秦巴山区中草药钮子七中微量元素的测定

用ICP-AES测定了秦巴山区独有的中草药钮子七中的2种常量营养性元素(钙、镁)和5种微量元素(铜、铬、铁、锌、锰)含量。钙4790.66μg.g-1、镁55.32μg.g-1、铜18.44μg.g-1、铬2.1μg.g-1、铁264.50μg.g-1、锌56.71μg.g-1、锰17.83μg.g-1,回收率均在96.2%—100.5%之间,结果表明,此方法简便、可靠,具有良好的精确度和准确性。并初步讨论了中草药钮子七中有益元素与治疗疾病的关系,并与中药材汉三七中微量元素含量相比较,二者微量元素含量略有差异。     

ICP-AES法同时测定茶叶中的锌、铁、锰、铜、镍、镁

研究了用硝酸＋硫酸＋高氯酸消解样品，用ICP－AES法同时测定茶叶中锌，铁，锰，铜，镍，镁的新方法，在选定的最佳条件下，测锌，铁，锰，铜，镍，镁的检出限分别为4．2，7.8,0.4,7.3,7.6,4.8ng.mL^-1，回收率为94．7％－104．2％，RSD为0．3％－4．7％，该法准确，快速，简便，适用于茶叶样品的测定，结果令人满意。     

茶叶及其组份的红外光谱研究

采用光学方法针对四种茶叶及其四种主要组份在800～3800 cm-1中红外"指纹"特征区域的光谱进行系统研究,采集了不同产地的碧螺春和铁观音以及决定茶叶品质的主要成份中咖啡因、谷氨酸和表儿茶素和花青素类物质的中红外光谱.通过建立模型对各特征光谱进行主成份拟合分析了茶叶品种、产地差异与各主要成份含量的关系.结果表明,不同茶叶之间的差异可表现在其主成份相对含量上:对于不同种类茶叶的碧螺春和铁观音,差异主要表现在茶叶有效成份的含量不同,前者中的各组份含量相对较低;对于不同产地的同种茶叶,差异主要表现在咖啡因和表儿茶素的相对含量不同,其中原产地茶叶中含量相对较高.此研究为利用光学方法对茶叶的种类和品质实现快速检测提供重要参考.     

FAAS测定妇炎康冲剂中的微量元素

测定妇炎康冲剂中多种微量元素的含量,为研究金属元素在妇炎康冲剂中的含量与药用功能提供有效的数据。采用空气-乙炔火焰原子吸收光谱法测定样品中微量元素的含量。样品中含有钙、镁、铁、硒,方法的加标回收率在98.4%—104.0%范围内,RSD(n=6)在1.0%—4.0%之间。镉、镍、铅未检出。妇炎康冲剂中含有钙、镁、铁、硒,值得进一步研究。     

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.