用新公式精确研究N_2分子部分电子态的离解能

本文使用代数方法(AM),研究了N_2分子的X~1∑_g~+、A~3∑_u~+、B~(′3)∑_u~-、a′~1∑_u~-、b′~1∑_u~+、B~3∏_g、c′_4~1∑_u~+等七个电子态的离解能;然后使用新公式计算了这些电子态的离解能,并分别与离解能的实验值进行了分析对比.结果表明:使用新公式得到的分子离解能与离解能的实验值更为接近.对于那些用实验方法还难以获得其离解能的电子态,该式提供了一种获得其离解能的新途径.     

用新公式精确研究N_2分子部分电子态的离解能

本文使用代数方法(AM),研究了N_2分子的X~1∑_g~+、A~3∑_u~+、B~(′3)∑_u~-、a′~1∑_u~-、b′~1∑_u~+、B~3∏_g、c′_4~1∑_u~+等七个电子态的离解能;然后使用新公式计算了这些电子态的离解能,并分别与离解能的实验值进行了分析对比.结果表明:使用新公式得到的分子离解能与离解能的实验值更为接近.对于那些用实验方法还难以获得其离解能的电子态,该式提供了一种获得其离解能的新途径.     

用新公式精确研究N_2分子部分电子态的离解能

本文使用代数方法(AM),研究了N_2分子的X~1∑~+_g、A~3∑~+_u、B~(′3)∑~-_u、a′~1∑~-_u、b′~1∑~+_u、B~3∏_g、c′_4~1∑~+_u等七个电子态的离解能;然后使用新公式计算了这些电子态的离解能,并分别与离解能的实验值进行了分析对比.结果表明:使用新公式得到的分子离解能与离解能的实验值更为接近.对于那些用实验方法还难以获得其离解能的电子态,该式提供了一种获得其离解能的新途径.     

用新公式研究K2分子部分电子态的离解能

本文使用孙卫国等人提出的基于微扰理论的代数方法（AM）,研究了碱金属K₂分子的五个电子态X¹∑_g⁺、a³∑_u⁺、O_g^-、B¹∏_u和3³∏_g的离解能;然后使用作者最近提出的新公式计算了这些电子态的离解能,并分别与实验值进行了比较.计算结果表明:使用新公式得到的分子离解能与实验值非常吻合.而对那些还没有离解能实验数据的电子态,该公式提供了一种推测其离解能的理论计算方法.     

双原子离子部分电子态的离解能的精确研究

本文使用基于微扰理论的代数方法(AM),研究了双原子离子F2+的X2Ⅱg,CO+的X2∑+,O2+的A2Ⅱu,BeH+的X1∑+四个电子态的离解能,然后使用最近提出的新公式计算了这些电子态的离解能,并分别与离解能的实验值进行了比较.研究结果表明:使用新公式得到的分子离解能与实验值更加接近;同时AM和新公式相结合的理论方法也适用于双原子离子体系.     

双原子离子部分电子态的离解能的精确研究

本文使用孙卫国提出的基于微扰理论的代数方法(AM),研究了双原子离子F2+的X2Πg,CO + 的X2Σ+, O2+的A2Πu ,BeH +的X1Σ+ 四个电子态的离解能,然后使用最近提出的新公式计算了这些电子态的离解能,并分别与离解能的实验值进行了比较．研究结果表明：使用新公式得到的分子离解能与实验值更加接近;同时AM和新公式相结合的理论方法也适用于双原子离子体系。     

用新公式研究K2分子部分电子态的离解能

文章使用孙卫国等人提出的基于微扰理论的代数方法(AM),研究了碱金属K2分子的 、 、 、 、 等五个电子态的离解能;然后使用作者最近提出的新公式计算了这些电子态的离解能,并分别与实验值进行了比较．计算结果表明：使用新公式得到的分子离解能与实验值非常吻合．而对那些还没有离解能实验数据的电子态,该式提供了一种获得其离解能的理论计算方法．     

NaRb分子部分电子态的完全振动能谱与离解能的精确研究

本文应用孙卫国等最近建立的代数方法(AM)和精确计算双原子分子离解能的新解析表达式研究了NaRb分子的X1∑ ,(1)3∑ 和a3∑ 电子态的完全振动能谱和离解能.得到的完全振动能谱既重复了已知的实验能级,又给出了尚没有实验数据的高振动激发能级的正确数值,获得的各电子态离解能精确地符合实验值.这些结果为需要NaRb分子的精确振动能谱和离解能的科学研究提供了重要的数据.     

NiCO分子结构与解析势能函数

用密度泛函理论的B3P86方法,对镍原子采用LANL2DZ收缩价基,碳原子和氧原子采用6-311+G~*基组,对NiC、NiO和NiCO体系的结构进行优化,计算表明:NiC分子基态为~1∑~+态,键长为R_e=0.16070 nm,离解能为3.62948 eV.NiO分子基态的平衡核间距为0.16784 nm,其电子态为~3∑~-,离解能为3.45119 eV,拟合得到Murrell-Sorbie势能函数;NiCO分子有两个线性稳定构型,其中一个构型为Ni—C≡O(C_(∞υ)),电子态为~1∑~+,平衡核间距为R_(NiC)=0.16621 nm,R_(co)=0.11519 nm,离解能为12.80476 eV,另一个为Ni—O≡C(C_(∞υ)),电子态是~1∑~+,平衡核间距为R_(co)=0.11470 nm,R_(NiO)=0.17636 nm,离解能为11.24679 eV.由微观过程的可逆性原理分析了分子的可能的离解极限,并用多体展式理论导出基态NiCO分子的势能函数,其等势面图准确地再现了NiCO分子的结构特征和离解能,由此讨论了Ni+CO,NiC+O,NiO+C分子反应的势能面静态特征.     

7LiD分子C1∑+的振动能谱与离解能的精确研究

在LeRoy与Bernstein的工作基础上,孙卫国等又建立了精确计算双原子分子离解能的新解析表达式.基于代数方法(AM)可以获得双原子分子的包含最高振动能级在内的所有高阶振动能级的精确数值这一事实,应用新公式研究了7LiD分子C1∑ 电子态的振动能谱和分子离解能,获得了与实验值符合得非常好的理论结果.     

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.