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TEA CO_2激光器11μm波段谱线特性研究 被引量:1
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作者 廖均梅 李育德 +3 位作者 李忠华 刘效勇 冉瑞江 陈梅 《激光与红外》 CAS CSCD 北大核心 2006年第10期940-942,共3页
采用双光栅谐振腔和增长放电增益区的方法,进行了TEA CO2激光器11μm波段谱线输出特性研究。在混合气体的比例为CO2∶N2∶He=70∶90∶270和总压430×133.3Pa情况下,获得数条谱线的激光输出。着重研究了波长为11013nm的激光谱线的输... 采用双光栅谐振腔和增长放电增益区的方法,进行了TEA CO2激光器11μm波段谱线输出特性研究。在混合气体的比例为CO2∶N2∶He=70∶90∶270和总压430×133.3Pa情况下,获得数条谱线的激光输出。着重研究了波长为11013nm的激光谱线的输出特性,其脉宽为400ns左右,且脉宽随电压变化。谱线能量随光栅中心的位移而变化,当光栅中心在放电区中心轴线上时有最大的能量输出。光斑能量分布接近低阶模或基模分布。 展开更多
关键词 TEA CO2激光器 热带 序列带 谱线特性
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高功率半导体泵浦固体激光器输出特性的研究 被引量:4
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作者 王海林 朱晓 +2 位作者 袁孝 周卓尤 曹红兵 《强激光与粒子束》 EI CAS CSCD 北大核心 2005年第B04期33-36,共4页
通过实验详细测量了水温、工作电流对二极管激光器发射波长的影响;采用光线追踪法模拟计算出在不同泵浦参数下半导体泵浦光在Nd:YAG棒内的分布情况,得到了圆周上泵浦模块的个数,泵浦光发散角等因素对泵浦光分布均匀性的影响。采用直接... 通过实验详细测量了水温、工作电流对二极管激光器发射波长的影响;采用光线追踪法模拟计算出在不同泵浦参数下半导体泵浦光在Nd:YAG棒内的分布情况,得到了圆周上泵浦模块的个数,泵浦光发散角等因素对泵浦光分布均匀性的影响。采用直接泵浦方式,分别设计了二种不同功率水平的半导体泵浦的Nd:YAG固体激光器聚光腔,得到了170和800 W的输出功率,并对激光器的输出特性进行详细测量,最大光光转换效率达37%,电光转换效率约为16%。 展开更多
关键词 二极管泵浦固体激光器 高功率 谱线特性
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乙酸的光谱学及其特性的研究 被引量:5
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作者 刘莹 兰秀风 +3 位作者 高淑梅 沈中华 陆建 倪晓武 《应用激光》 CSCD 北大核心 2002年第6期559-562,共4页
采用光栅光谱仪获得了波长为 2 5 4nm(Δλ1 /2 4nm)的紫外光激励乙酸溶液的紫外吸收光谱和不同浓度溶液的荧光光谱 ,并对其产生机理和谱线特性进行了研究。实验结果和理论分析表明 ,波长为 2 5 4nm的紫外光诱导乙酸分子发出的荧光是由... 采用光栅光谱仪获得了波长为 2 5 4nm(Δλ1 /2 4nm)的紫外光激励乙酸溶液的紫外吸收光谱和不同浓度溶液的荧光光谱 ,并对其产生机理和谱线特性进行了研究。实验结果和理论分析表明 ,波长为 2 5 4nm的紫外光诱导乙酸分子发出的荧光是由乙酸分子上的荧光团 -C =O -产生的 ,其量子转换效率可达 5 0 %以上 ;乙酸溶液的荧光量子产额将随浓度发生明显的变化。 展开更多
关键词 乙酸 紫外光 荧光光 谱线特性
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Application of Image Enhancement Techniques to Potential Field Data 被引量:6
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作者 张丽莉 郝天珧 +1 位作者 吴健生 王家林 《Applied Geophysics》 SCIE CSCD 2005年第3期145-152,i0001,共9页
In this paper the application of image enhancement techniques to potential field data is briefly described and two improved enhancement methods are introduced. One method is derived from the histogram equalization tec... In this paper the application of image enhancement techniques to potential field data is briefly described and two improved enhancement methods are introduced. One method is derived from the histogram equalization technique and automatically determines the color spectra of geophysical maps. Colors can be properly distributed and visual effects and resolution can be enhanced by the method. The other method is based on the modified Radon transform and gradient calculation and is used to detect and enhance linear features in gravity and magnetic images. The method facilites the detection of line segments in the transform domain. Tests with synthetic images and real data show the methods to be effective in feature enhancement. 展开更多
关键词 image enhancement histogram equalization Radon transform and potential field data
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Analytical Results of Eigenstates and Eigenenergies for Three Kinds of Models Describing N-mode Multiphoton Process
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作者 YANGWen-Xing LIJia-Hua +2 位作者 LIWei-Bin CHENAi-Xi JINLi-Xia 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第1期22-26,共5页
We obtain. the exact analytical results of all the eigenvalues and eigenstates for three kinds of models describing N-mode multiphoton process without using the assumption of the Bethe ansatz. The exact analytical res... We obtain. the exact analytical results of all the eigenvalues and eigenstates for three kinds of models describing N-mode multiphoton process without using the assumption of the Bethe ansatz. The exact analytical results of all the eigenstates and eigenvalues are in terms of a parameter lambda for three kinds of models describing N-mode multiphoton process. The parameter is shown to be determined by the roots of a polynomial and is solvable analytically or numerically. Moreover, these three kinds of models can be processed with the same procedure. 展开更多
关键词 SPECTRUM EIGENSTATE EIGENVALUE
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Raman Spectra and Crystallographic Properties of a New NLO Material,ZnCd(SCN)_4 Crystal
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作者 ZHOUM LILX 《Semiconductor Photonics and Technology》 CAS 2000年第4期220-223,241,共5页
The crystallographic properties and R aman spectra of the title compound ZnCd(SCN) 4, which is a new nonlinear optica l crystal(NLO), are reported for the first time. This crystal is orthorhombic and its space group i... The crystallographic properties and R aman spectra of the title compound ZnCd(SCN) 4, which is a new nonlinear optica l crystal(NLO), are reported for the first time. This crystal is orthorhombic and its space group is I - 4 with unit cell parameters a =1.113 5(0.2) nm, c =0.437 60(1) nm. There are two formulas per unit cell. Raman spectra of zinc cadmium thiocyanatec (ZCTC) are given and the electron activities in the crystal are shown. 展开更多
关键词 Raman spectra Nonlinear optical crystal Crystallographic properties
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200W高功率半导体泵浦固体激光器输出特性研究 被引量:3
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作者 王海林 张争 +1 位作者 曹红兵 周卓尤 《应用激光》 CSCD 北大核心 2006年第5期336-338,共3页
通过实验测量了工作电流对半导体激光器发射波长的影响;采用光线追踪法模拟计算出泵浦光在Nd:YAG棒内的分布情况,采用直接泵浦方式,设计了高效率的半导体侧面泵浦Nd:YAG固体激光模块,最大输出功率为218W,最大光-光效率达37%,电光效率约... 通过实验测量了工作电流对半导体激光器发射波长的影响;采用光线追踪法模拟计算出泵浦光在Nd:YAG棒内的分布情况,采用直接泵浦方式,设计了高效率的半导体侧面泵浦Nd:YAG固体激光模块,最大输出功率为218W,最大光-光效率达37%,电光效率约为18.5%。 展开更多
关键词 半导体泵浦固体激光器 高功率 谱线特性
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Spectrum Allocation for Cognitive Radio Networks with Non-Deterministic Bandwidth of Spectrum Hole 被引量:1
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作者 Jie Huang Xiaoping Zeng +2 位作者 Xiaoheng Tan Xin Jian Yuan He 《China Communications》 SCIE CSCD 2017年第3期87-96,共10页
The spectrum allocation for cognitive radio networks(CRNs) has received considerable studies under the assumption that the bandwidth of spectrum holes is static. However, in practice, the bandwidth of spectrum holes i... The spectrum allocation for cognitive radio networks(CRNs) has received considerable studies under the assumption that the bandwidth of spectrum holes is static. However, in practice, the bandwidth of spectrum holes is time-varied due to primary user/secondary user(PU/SU) activity and mobility, which result in non-determinacy. This paper studies the spectrum allocation for CRNs with non-deterministic bandwidth of spectrum holes. We present a novel probability density function(PDF) through order statistics as well as its simplified form to describe the statistical properties of spectrum holes, with which a statistical spectrum allocation model based on stochastic multiple knapsack problem(MKP) is formulated for spectrum allocation with non-deterministic bandwidth of spectrum holes. To reduce the computational complexity, we transform this stochastic programming problem into a constant MKP through exploiting the properties of cumulative distribution function(CDF), which can be solved via MTHG algorithm by using auxiliary variables. Simulation results illustrate that the proposed statistical spectrum allocation algorithm can achieve better performance compared with the existing algorithms when the bandwidth of spectrum holes is time-varied. 展开更多
关键词 cognitive radio time-varied spectrum allocation non-deterministic bandwidth of spectrum holes stochastic programming
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Upconversion Luminescence of Er^3+ and Co-Doped Er^3+/Yb^3+ Novel Transparent Oxyfluoride Glasses and Glass Ceramics: Spectral and Structural Properties
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作者 Arzumanyan Grigory Vartic Victoria +6 位作者 Kuklin Alexander Soloviov Dmitry Rachkovskaya Galina Zacharevich Galina Trusova Ekaterina Skoptsov Nikolay Yumashev Konstantin 《Journal of Physical Science and Application》 2014年第3期150-158,共9页
Transparent oxyfluoride silicate precursor glasses and glass ceramics with the novel composition (1) SiO2-PbO-PbFE-Er2O3, (2) SiO2-GeOE-PbO-PbFE-Er2O3 (3) SiO2-Al2O3-Y2O3-Na2O-NaF-LiF-Er2O3-YbF3 doped with Er^3... Transparent oxyfluoride silicate precursor glasses and glass ceramics with the novel composition (1) SiO2-PbO-PbFE-Er2O3, (2) SiO2-GeOE-PbO-PbFE-Er2O3 (3) SiO2-Al2O3-Y2O3-Na2O-NaF-LiF-Er2O3-YbF3 doped with Er^3+ and co-doped with Er^3+/Yb^3+ ions were synthesized. X-ray diffraction analysis (XRD) and Er3+ absorption spectra revealed precipitation of PbF2 nanocrystals dispersed in the glassy matrix. Under 980 nm laser excitation, intense green, red and near IR bands of upconversion luminescence (UCL) were recorded both before and after heat treatment. In the glass ceramics the upconversion intensity increased significantly. To our knowledge, for the first time the composition of the glass ceramics characterized by the small-angle neutron scattering (SANS) showed the cluster organization of PbF2 nanocrystals. 展开更多
关键词 Visible to near-infrared upconversion rare-earth luminescence oxyfluoride glass ceramics small-angle neutron scattering.
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长周期光纤光栅的透射光谱特征
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作者 陈鹏程 《光谱实验室》 CAS CSCD 北大核心 2011年第4期2066-2068,共3页
用Matlab编程的方法对长周期光纤光栅的透射光谱谱线特性进行了研究,数值模拟了长周期光纤光栅周期对光谱谱线的影响。研究结论为长周期光纤光栅的设计提供了理论依据。
关键词 长周期光纤光栅 透射光谱线特性 MATLAB编程
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Cyclostationary Property Based Spectrum Sensing Algorithms for Primary Detection in Cognitive Radio Systems 被引量:1
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作者 岳文静 郑宝玉 孟庆民 《Journal of Shanghai Jiaotong university(Science)》 EI 2009年第6期676-680,共5页
To implement the primary signal without interference in cognitive radio systems, cognitive radios can detect the presence of the primary user in low SNR. Currently, energy detector is the most common way of spectrum s... To implement the primary signal without interference in cognitive radio systems, cognitive radios can detect the presence of the primary user in low SNR. Currently, energy detector is the most common way of spectrum sensing because of its low computational complexity. However, performunce of the method will be possibly degraded due to the uncertainty noise. This paper illustrates the benefits of one-order and two-order cyclostationary properties of primary user's signals in time domain. These feature detection techniques in time domain possess the advantages of simple structure and low computational complexity comparing with spectral feature detection methods. Furthermore, performance of the one-order and two-order feature detection is studied and the analytical results are given. Our analysis and numerical results show that the sensing performance of the one-order feature detection is improved significantly comparing with conventional energy detector since it is robust to noise. Meanwhile, numerical results show that the two-order feature detection technique is better than the one-order feature detection. However, this benefit comes at the cost of hardware burdens and power consumption due to the additional multiplying algorithm. 展开更多
关键词 cognitive radio spectrum sensing cyclostationary feature detection
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Multiply Kink and Anti-Kink Solutions for a Coupled Camassa–Holm Type Equation
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作者 Yuan-Li Li Qi-Lao Zha 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第12期609-614,共6页
This article amis at revealing dynamical behavior of a coupled Camassa–Holm type equation, which was proposed by Geng and Wang based on a 4×4 matrix spectral problem with two potentials. Its kink and anti-kink s... This article amis at revealing dynamical behavior of a coupled Camassa–Holm type equation, which was proposed by Geng and Wang based on a 4×4 matrix spectral problem with two potentials. Its kink and anti-kink solutions are presented explicitly. In particular, some exact multi-kink and anti-kink wave solutions are discussed and under some conditions, the kink and anti-kinks look like hat-shape solitons. The dynamic characters of the obtained solutions are investigated by figures. The method used in this paper can be widely applied to looking for the multi-kinks for Camassa–Holm type equations possessing cubic nonlinearity. 展开更多
关键词 kink solution dynamic behavior coupled Camassa–Holm type equation
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