肉豆蔻与肉豆蔻衣的微量元素比较研究

对肉豆蔻和肉豆蔻衣中10种微量元素进行了含量测定,并进行对比。采用干法灰化处理样品,用电感耦合等离子体-原子发射光谱法(ICP-AES)同时测定了2种样品中的10种微量元素的含量。该法的加标回收率为90.0%—105.2%,相对标准偏差为0.31%—4.77%,具有良好的准确度和精密度。2种药材的微量元素含量有着明显的差异。     

ICP-MS测定中草药狼毒中稀土和微量元素

研究了电感耦合等离子体质谱法(ICP-MS)测定中草药狼毒中稀土和微量元素的方法,样品处理通过低温灰化方法与硝酸-过氧化氢消解方法比较,实验确认微量元素采用低温灰化法制备样品, 稀土元素采用酸消化法制备样品,可以满足该方法检测要求,具有测试方法准确、快速等优点。 方法的准确度在1.21%～15.15%, 精密度在0.38%～8.54%之间。 该方法完全可以满足中草药样品中稀土和微量元素检测要求。     

原子吸收光谱法测定龙须菜中7种微量元素含量

采用干法灰化-原子吸收光谱法测定龙须菜中的铜、铁、锰、镁、锌、铬、镍7种微量元素含量.结果表明:龙须菜中含有丰富的人体必需的微量元素,作为食用蔬菜对人体补充微量元素有较高的利用价值.该法具有良好的准确度和精密度,加标回收在90.0%-100.2%范围内,相对标准偏差(RSD)≤5.0%,结果可靠,操作方便,可用于同类藻类制品的测定.     

公丁香中多种金属元素的ICP-AES研究

探讨公丁香中多种金属元素的测定方法,采用湿法硝酸-双氧水进行消解,用电感耦合等离子体原子发射光谱法(ICP-AES)同时测定试样中钾、镁及多种微量元素铅、铜、铁、铬、锌、锰等的方法.其检出限为0.000 4～0.095 4μg·mL-1,变异系数为0.4%～4.9%,回收率在91.8%～112.2%,结果令人满意.发现中药公丁香中含有比较丰富的锰元素,微量元素在中药中可能起到一定的药理作用,用ICP-AES测定中药中微量元素以评价中药价值具有重要的意义.     

ICP-AES同时测定不同产地贝母中多种微量元素

探讨贝母中多种微量元素的最佳测定方法.采用微波消解法对贝母进行消解,用电感耦合等离子体发射光谱法(ICP-AES)同时测定贝母中元素.各元素精密度在0.93%,检测限为6%.ICP-AES具有灵敏,准确及多元素同时测定的优点,方法简便,试样分析结果满意,可用于贝母中多种微量元素的测定.     

原子吸收法同时测定人发中锌铁铜锰钾钙和镁

本文研究测定人发中微量元素,讨论了洗发、消化时污染可能引起的误差。提出用中性洗涤剂清洗人发,干法灰化,1%硝酸溶解,原子吸收法测定,操作简单,污染腐蚀少回收率达90%以上。与其它方法比较,相对误差一般为20%以下。     

不同消解对原子吸收光谱法测定三七中重金属铬的影响

以云南文山三七为材料,分析研究了用干法灰化、湿法消解前处理样品对原子吸收光谱法测定三七中重金属C r含量的影响,方法的相关系数为0.9993,干法灰化回收率为95.02%,湿法消解回收率为93.03%,分析结果满意。结果表明,干法灰化的最佳条件为灰化温度500—600℃、灰化时间6—8h。湿法消解的最佳消解体系为HNO3:HC lO4(V/V)=4:1体系。用干法灰化或常压下湿法消解处理样品,原子吸收光谱法可以准确测定三七中重金属C r含量,且方法简单、快捷。云南文山三七粉中重金属C r含量为1.8178μg/g。     

ICP-OES测定奶茶粉中的常量、微量元素

采用干法灰化法处理奶茶粉样品,建立电感耦合等离子体发射光谱法(ICP-OES)同时测定奶茶粉中常量、微量元素的方法.该方法以钪作为内标以补偿仪器波动,采用不同标准系列分组以消除光谱干扰.方法检出限为0.02-8.77μg/g,相对标准偏差均小于3%,回收率为93.9%-109.4%.方法操作简单、分析速度快、灵敏度高、...     

用ICP-AES方法测定淀粉中铅、砷的含量

采用ICP-AES(电感耦合等离子体发射光谱)法,以硝酸镍作为基体改进剂,对淀粉中的铅、砷含量进行了测定;探讨了样品灰化方法及灰化原子化温度、基体改进剂对测定结果的影响.实验结果表明,用ICP-AES方法测定淀粉样品中铅、砷一类有害重金属含量,数据、结果的重现性好,方法简便易行、测定结果准确.     

ICP-AES测定大鼠胃内硫糖铝中的铝

采用干法灰化,电感耦合等离子体-原子发射光谱法（ICP-AES）测定正常大鼠胃内硫糖铝中的铝量。结果表明,最佳分析波长为396.153nm,检出限为8ng·mL^-1,各组内相对标准偏差均小于0.81%,组间相对标准偏差均小于13.4%,铝的回收率在96.0%—99.5%之间,表明ICP-AES测定大鼠胃内硫糖铝中铝的精密度、准确度良好,满足生物样品分析要求。大鼠灌服硫糖铝6h后胃内的铝基本排空,与正常胃排空时间一致,表明硫糖铝中的铝对正常胃粘膜无粘附作用。     

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.