差分脉冲极谱法测定蒙药肉蔻五味丸中的锗

采用差分脉冲扫描法,在pH=1.30含有3,4-二羟基苯甲醛(DHB)的H2SO4底液中,测得无机锗的脉冲极谱波,峰电位为Ep=-0.53V,Ge()浓度在1.03×10-5—1.04×10-4mol·L-1范围内与峰电流呈线性关系,利用差分脉冲极谱法可以测定蒙药中总锗、无机锗和有机锗,得到了满意的结果。     

两种蒙药无机锗和有机锗的测定

本文采用方波极谱法 ,在 p H=1.30的 H2 SO4和 3,4 -二羟基苯甲醛 (DHB)的底液中 ,获得无机锗的方波极谱波 ,峰电位为 Ep=- 0 .5 2 V,在浓度 2 .8× 10 -5— 2 .8× 10 -3 mol/ L内与峰电流呈线性关系 ,方法简单。本法用于蒙药中无机锗和有机锗的测量 ,测定结果满意     

2-三苯基锗基乙基苯基酮、4-三氯锗基-4-甲基-2-戊酮及其类似物Raman及IR光谱

我们合成有机锗化合物的重要中间体 4-三氯锗基 - 4-甲基 - 2 -戊酮 ( A)、3-三氯锗基 -3,5,5-三甲基环己酮 ( B)、2 -三氯锗基 - 2 -苯基乙基苯基酮 ( C)、2 -三苯基锗基乙基苯基酮 ( D) ,测量了他们的 Raman和 IR光谱并进行了讨论。在化合物 A- D的 Raman和 IR光谱 ,苯环中的 C- H伸缩振动 ,饱和 C- H伸缩振动 ,饱和 Ge- C伸缩振动等特征数据基本一致。C=O伸缩振动在 Raman和 IR光谱中位置基本一致 ,但在红外光谱中均为强吸收带 ,而在 Raman光谱中的峰强度差别则非常大 ,化合物 A、D的峰非常弱 ,而 C的峰则很强 ,化合物 A- C的 Ge- Cl振动均在 390 cm- 1附近出现强峰。     

薄膜吸收对宽带反射镜的影响

对二组λ/4膜系迭加的宽带反射镜进行了分析和计算.当膜层的复折射率为 N_H=2.3-5×10~(-4)和N_L=1.46-il×10~(-5)时,反射镜出现二个吸收峰,峰值达7%,文中阐述了产生吸收峰的原因,并提出了一种改善吸收蜂的简单膜系.     

Er3+掺杂的锗铋酸玻璃光谱性质的研究

制备了一种新型掺Er3 锗铋酸盐玻璃。分析了吸收光谱和上转换荧光光谱,并应用Judd-Ofelt理论计算了锗铋酸盐玻璃的3个强度参量tΩ(t=2,4,6),分别为Ω2=3.35×10-20cm2,Ω4=1.34×10-20cm2以及Ω6=0.67×10-20cm2。研究了在两种不同的激发光下(980和808 nm)锗铋酸盐玻璃的发光机制。根据McCumber理论,分析了在1.55μm光通讯窗口的光谱性质,计算了能级4I13/2→4I15/2跃迁的受激发射截面,结果显示掺Er3 锗铋酸盐玻璃具有较宽的荧光半高宽和较大的受激发射截面。因此有希望成为高效的上转换发光材料和1.55μm光通讯材料。     

锌(Ⅱ)-2-(5-溴-2-吡啶偶氮)-5-二乙氨基酚-亚硝酸钠体系的极谱吸附波

在(CH)_6N_4-HCl缓冲溶液中(pH5.6),当有NaNO_2存在时,Zn(Ⅱ)-2-(5-溴-2-吡啶偶氮)-5-二乙氨基酚络合物有一灵敏的吸附波,峰电位在-0.448V(vs.SCE)左右,该波的二阶导数峰峰电流与锌质量浓度在6.8×10~(-9)-1.69×10~(-7)mol/L范围内呈线性关系(r=0.9989,n=10)。检出限为0.001mg/L。本方法回收率在95.1%—104.9%之间。经多种电化学方法证明该波为络合物吸附波,其电极过程为不可逆过程。此外还试验了多种离子对峰电流I_P″的影响。所拟定的方法可用于红枣中微量锌(Ⅱ)的测定。     

极谱分析法连续测定痕量铅和镉

研究了 Pb2 + 和 Cd2 + 与 KCl-酒石酸钠 -三乙醇胺 -明胶体系的二次导数极谱波。在 p H=4 .5的 HAc-Na Ac介质中 ,Pb2 + 和 Cd2 + 分别于 - 0 .4 6 V和 - 0 .6 4V电位处产生一良好的极谱波。峰电流与 Pb2 + 和Cd2 + 的浓度分别在 1× 10 -5— 3× 10 -1g· L-1和 5× 10 -5— 6× 10 -3 g· L-1范围内呈线性关系。 Pb2 + 和Cd2 +的检出限分别为 1× 10 -7g·L-1和 5× 10 -7g·L-1。本法准确、简便、快速、选择性高。已直接用于饮料中铅和镉的连续测定 ,同时也对酒及面粉样品进行了测定 ,回收率分别为 99.9%— 10 0 .1%和 97.0 %—10 4 .8%。     

含纳米锗粒二氧化硅薄膜的光致发光研究

以锗-二氧化硅(GSO)复合靶作为溅射靶，改变靶上锗与总靶面积比为0%，5%和10%，用射频磁控溅射方法在p型硅衬底上淀积了含锗量不同的三种二氧化硅薄膜.各样品分别在氮气氛中经过300至900℃不同温度的退火处理.通过对样品所作Raman散射光谱的分析，发现随着锗在溅射靶中面积比的增加，所制备的氧化硅薄膜中纳米锗粒的平均尺寸在增大.确定出随着退火温度由600℃升高到900℃，GSO(5%)样品中纳米锗粒的平均直径由5.4nm增至9.5nm.含纳米锗粒大小不同的二氧化硅薄膜的光致发光谱中都存在位于2.1eV     

苯基荧光酮光度法测定煤矸石中微量锗

在磷酸介质中 ,吐温 - 2 0存在下 ,锗 ( )与苯基荧光酮反应生成稳定的络合物 ,其最大吸收波长为5 0 0 nm,表观摩尔吸光系数ε=1.2 7× 10 5L· mol-1· cm-1。锗含量在 0— 10μg/2 5 m L范围内符合比耳定律 ,测得络合物的组成比为 :Ge( )∶苯基荧光酮 =1∶ 2。方法的灵敏度高 ,选择性好 ,络合物稳定 2 4 h以上 ,用于测定煤矸石中微量锗 ,结果令人满意     

锗/多孔硅和锗/氧化硅薄膜光致发光的比较研究

采用磁控溅射技术,以锗为溅射靶,在多孔硅上沉积锗薄膜,沉积时间分别为4,8和12 min,及以锗-二氧化硅复合靶为溅射靶,在n型硅衬底上沉积了含纳米锗颗粒的氧化硅薄膜,锗与总靶的面积比分别为5%,15%,30%.各样品在氮气氛中分别经过300,600及900℃退火30 min.对锗/多孔硅和锗/氧化硅薄膜进行了光致发光谱的对比研究,用红外吸收谱分析了锗/多孔硅的薄膜结构.实验结果显示,锗/多孔硅薄膜的发光峰位于517 nm附近,沉积时间对发光峰的强度有显著影响,锗层越厚峰强越弱.锗/氧化硅薄膜的发光峰位于580 nm附近,锗与总靶的面积比对发光峰的强度影响较大,锗/氧化硅薄膜中的锗含量越高峰强越弱.不同的退火温度对样品的发光峰强及峰位均没有明显影响.可以认为锗/多孔硅的发光峰是由多孔硅与孔间隙中的锗纳米晶粒两者界面的锗相关缺陷引起的,而锗/氧化硅的发光峰来自于二氧化硅的发光中心.     

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.