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Saturated absorption spectrum of cesium micrometric-thin cell with suppressed crossover spectral lines
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作者 韩俊龙 王博闻 +5 位作者 郑俊鹤 陈书源 肖伟 吴腾 郭弘 彭翔 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第7期353-360,共8页
Micrometric-thin cells(MCs)with alkali vapor atoms have been valuable for research and applications of hyperfine Zeeman splitting and atomic magnetometers under strong magnetic fields.We theoretically and experimental... Micrometric-thin cells(MCs)with alkali vapor atoms have been valuable for research and applications of hyperfine Zeeman splitting and atomic magnetometers under strong magnetic fields.We theoretically and experimentally study the saturated absorption spectra using a 100-μm cesium MC,where the pump and probe beams are linearly polarized with mutually perpendicular polarizations,and the magnetic field is along the pump beam.Because of the distinctive thin chamber of the MC,crossover spectral lines in saturated absorption spectra are largely suppressed leading to clear splittings of hyperfine Zeeman transitions in experiments,and the effect of spatial magnetic field gradient is expected to be reduced.A calculation method is proposed to achieve good agreements between theoretical calculations and experimental results.This method successfully explains the suppression of crossover lines in MCs,as well as the effects of magnetic field direction,propagation and polarization directions of the pump/probe beam on saturated absorption spectrum.The saturated absorption spectrum with suppressed crossover lines is used for laser frequency stabilization,which may provide the potential value of MCs for high spatial resolution strong-field magnetometry with high sensitivity. 展开更多
关键词 micrometric-thin cells saturated absorption spectrum hyperfine Zeeman splitting crossover spectral lines laser frequency stabilization
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Balmer H_α,H_β and H_γ Spectral Lines Intensities in High-Power RF Hydrogen Plasmas 被引量:1
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作者 王松柏 雷光玖 +1 位作者 刘东平 杨思泽 《Plasma Science and Technology》 SCIE EI CAS CSCD 2014年第3期219-222,共4页
Hα(Balmer-alpha), Hβ (Balmer-beta) and Hγ (Balmer-gamma) spectral line inten- sities in atomic hydrogen plasma are investigated by using a high-power RF source. The intensities of the Hα, Hβ and Hγ spectra... Hα(Balmer-alpha), Hβ (Balmer-beta) and Hγ (Balmer-gamma) spectral line inten- sities in atomic hydrogen plasma are investigated by using a high-power RF source. The intensities of the Hα, Hβ and Hγ spectral lines are detected by increasing the input power (0-6 kW) of ICPs (inductively coupled plasmas). With the increase of net input power, the intensity of Hα im- proves rapidly (0-2 kW), and then reaches its dynamic equilibrium; the intensities of Hβ can be divided into three processes: obvious increase (0-2 kW), rapid increase (2-4 kW), almost constant (4-6 kW); while the intensities of Hγ increase very slowly. The energy levels of the excited hydro- gen atoms and the splitting energy levels produced by an obvious Stark effect play an important role in the results. 展开更多
关键词 Keywords: high-power RF (radio frequency) source ICPs (inductively coupled plasmas) and spectral lines intensity Boltzmann distribution law Stark effect transitionprobability
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Stark-Broadened Profiles of the Spectral Line P_α in He Ⅱ Ions
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作者 段斌 Muhammad Abbas Bari +2 位作者 吴泽清 颜君 王建国 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第3期24-27,共4页
We report a systematic method to perform calculations of spectral line broadening parameters in plasmas. This method is applied to calculate Stark-broadening line profiles of Pα(n = 4 → n = 3) transitions under ce... We report a systematic method to perform calculations of spectral line broadening parameters in plasmas. This method is applied to calculate Stark-broadening line profiles of Pα(n = 4 → n = 3) transitions under certain specific plasma conditions, by treating this case as an example. In the framework of the fully relativistic Dirac R- matrix theory, we calculate the electron-impact broadening operators, which are assumed to be diagonal matrix to simplify the situation. The electric microfield distribution function is calculated by retaining Hooper's formalism. The dipole matrix elements and atomic structure parameters used in these calculations have been obtained from atomic structure GRASP code. Based on this required data, we calculate the Stark-broadened line profiles of the Paschen spectral lines in He Ⅱ ions in a systematic manner. Overall, there is a very good agreement between our calculated Stark-broadened line profiles and other line Our reported spectral line-broadening data have real also play a fundamental role in plasma modeling. broadening numerical simulation codes (Sire U and MELS). applications in plasma spectroscopy, plasma diagnosis and 展开更多
关键词 Stark-Broadened Profiles of the spectral line P line on is II in He IONS of
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Extreme ultraviolet and soft x-ray spectral lines in Rb ⅩⅩⅨ
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作者 Indu Khatri Arun Goyal +2 位作者 Sunny Aggarwal A K Singh Man Mohan 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第3期134-144,共11页
An extensive theoretical set of atomic data for Rb XXIX in a wide range with L-shell electron excitations to the M-shell has been reported. We have computed energy levels for the lowest 113 fine structure levels of Rb... An extensive theoretical set of atomic data for Rb XXIX in a wide range with L-shell electron excitations to the M-shell has been reported. We have computed energy levels for the lowest 113 fine structure levels of Rb XXIX. The fully relativistic multiconfigurational Dirac-Fock method (MCDF) within the framework of Dirac-Coulomb Hamiltonian taking quantum electrodynamics (QED) and Breit corrections into account has been adopted for calculations. Radiative data are reported for electric dipole (El), magnetic dipole (MI), electric quadrupole (E2), and magnetic quadrupole (M2) transitions from the ground level, although calculations have been performed for a much larger number of levels. To assess the accuracy of results, we performed analogous calculations using flexible atomic code (FAC). Comparisons are made with existing available results and a good agreement has been achieved. Most of the wavelengths calculated lie in the soft x-ray (SXR) region. Lifetimes for all 113 levels have also been provided for the first time. Additionally, we have provided the spectra for allowed transitions from n = 2 to n = 3 within the x-ray region and also compared our SXR photon wavelengths with experimentally recognized wavelengths. We hope that our results will be beneficial in fusion plasma research and astrophysical applications. 展开更多
关键词 energy levels WAVELENGTHS radiative rates spectral lines
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Atomic epn(ep) Spin Models and Spectral Lines
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作者 Daekyoum Kim Baik-Hyon Ha 《American Journal of Analytical Chemistry》 2015年第13期1030-1037,共8页
We confirmed that how many kinds of epn spins the atoms have by calculating heat capacity of metals according to energy levels in the previous reference. To know more the spin models of epn of hydrogen and helium are ... We confirmed that how many kinds of epn spins the atoms have by calculating heat capacity of metals according to energy levels in the previous reference. To know more the spin models of epn of hydrogen and helium are imagined and their line spectra are counted. And the explanation of interference is discussed. Gas atoms make line spectra by optical interference. Solid atoms make them by exciting the lowest epns of their cluster first. They all make s, p energy orbit. One axis is composed of two epns. 1s or 2s of atoms except for lithium generally makes the symmetric axis. When each energy level is filled up by epns, these are symmetrically paired first. The atoms which fit the number of line spectra correctly by optical interference are hydrogen and helium. By counting the number of alignments of epns spins within the cluster, the atoms which fit the number of line spectra correctly are lithium, beryllium and phosphorus. The number of line spectra of the rest atoms which we have counted approaches the experimented numbers approximately, not correctly. 展开更多
关键词 ATOMIC Model ATOMIC CLUSTER spectral lineS RESONANCE
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Effect of Characteristic Spectral Lines on Rock Identification of LIBS
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作者 Ke ZhiQuan Wang YangEn +2 位作者 Xu Yi Dong XiPu Zhou MaoHui 《Journal of Physical Science and Application》 2015年第4期296-308,共13页
关键词 识别精度 特征对 BP神经网络 谱线 岩石样品 特征光谱 岩石分类 线模型
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Degenerate cascade fluorescence: Optical spectral-line narrowing via a single microwave cavity
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作者 胡亮 胡响明 胡庆平 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第6期346-358,共13页
For a three-level atom, two nondegenerate(even microwave and optical) electric dipole transitions are usually allowed;for either of these, the fluorescence spectra are well-described in terms of spontaneous transition... For a three-level atom, two nondegenerate(even microwave and optical) electric dipole transitions are usually allowed;for either of these, the fluorescence spectra are well-described in terms of spontaneous transitions from a triplet of dressed sublevels to an adjacent lower-lying triplet. When the three dressed sublevels are equally spaced from each other, a remarkable feature known as degenerate cascade fluorescence takes place, which displays a five-peaked structure. We show that a single cavity can make all the spectral lines extremely narrow, whether they arise from cavity-coupled or cavity-free transitions. This effect is based on intrinsic cascade lasing feedback and makes it possible to use a single microwave cavity(even a bad cavity) to narrow the spectral lines in the optical frequency regime. 展开更多
关键词 resonance fluorescence narrow spectral lines microwave cavity
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A METHOD DESCRIBING PROFILE ASYMMETRY OF SPECTRAL LINES
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作者 顾啸马 李秋莎 《Chinese Science Bulletin》 SCIE EI CAS 1991年第19期1618-1621,共4页
One of the common spectral features is asymmetry of spectral line profile for the solar activity phenomena, such as flare, erupted prominence and loop prominence system. The asymmetry is a spectral reflection of the c... One of the common spectral features is asymmetry of spectral line profile for the solar activity phenomena, such as flare, erupted prominence and loop prominence system. The asymmetry is a spectral reflection of the complex active phenomena. In general, a radial motion of matter and some special physical conditions are responsible for the asymmetry of a spectral line profile. So, it is an important aspect in researching the activity phenomena of the Sun to observe and study the asymmetry of the profile. Ye Shi-hui et al. studied the ef- 展开更多
关键词 the SUN spectral line PROFILE asymmetry.
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Gridless Variational Bayesian Inference of Line Spectral from Quantized Samples
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作者 Jiang Zhu Qi Zhang Xiangming Meng 《China Communications》 SCIE CSCD 2021年第10期77-95,共19页
Efficient estimation of line spectral from quantized samples is of significant importance in information theory and signal processing,e.g.,channel estimation in energy efficient massive MIMO systems and direction of a... Efficient estimation of line spectral from quantized samples is of significant importance in information theory and signal processing,e.g.,channel estimation in energy efficient massive MIMO systems and direction of arrival estimation.The goal of this paper is to recover the line spectral as well as its corresponding parameters including the model order,frequencies and amplitudes from heavily quantized samples.To this end,we propose an efficient gridless Bayesian algorithm named VALSE-EP,which is a combination of the high resolution and low complexity gridless variational line spectral estimation(VALSE)and expectation propagation(EP).The basic idea of VALSE-EP is to iteratively approximate the challenging quantized model of line spectral estimation as a sequence of simple pseudo unquantized models,where VALSE is applied.Moreover,to obtain a benchmark of the performance of the proposed algorithm,the Cram′er Rao bound(CRB)is derived.Finally,numerical experiments on both synthetic and real data are performed,demonstrating the near CRB performance of the proposed VALSE-EP for line spectral estimation from quantized samples. 展开更多
关键词 variational Bayesian inference expectation propagation QUANTIZATION line spectral estimation MMSE gridless
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Iterative Reweighted <i>l</i><sub>1</sub>Penalty Regression Approach for Line Spectral Estimation
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作者 Fei Ye Xian Luo Wanzhou Ye 《Advances in Pure Mathematics》 2018年第2期155-167,共13页
In this paper, we proposed an iterative reweighted l1?penalty regression approach to solve the line spectral estimation problem. In each iteration process, we first use the ideal of Bayesian lasso to update the sparse... In this paper, we proposed an iterative reweighted l1?penalty regression approach to solve the line spectral estimation problem. In each iteration process, we first use the ideal of Bayesian lasso to update the sparse vectors;the derivative of the penalty function forms the regularization parameter. We choose the anti-trigonometric function as a penalty function to approximate the?l0? norm. Then we use the gradient descent method to update the dictionary parameters. The theoretical analysis and simulation results demonstrate the effectiveness of the method and show that the proposed algorithm outperforms other state-of-the-art methods for many practical cases. 展开更多
关键词 line spectral Estimation PENALTY Regression Bayesian Lasso ITERATIVE Reweighted APPROACH
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Legendre Rational Spectral Method for Nonlinear Klein-Gordon Equation 被引量:3
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作者 Zhongqing Wang Benyu Guo 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2006年第2期143-149,共7页
A Legendre rational spectral method is proposed for the nonlinear Klein-Gordon equation on the whole line. Its stability and convergence are proved. Numerical results coincides well with the theoretical analysis and d... A Legendre rational spectral method is proposed for the nonlinear Klein-Gordon equation on the whole line. Its stability and convergence are proved. Numerical results coincides well with the theoretical analysis and demonstrate the e?ciency of this approach. 展开更多
关键词 勒让德有理数光谱方法 非线性方程 克莱因-戈登方程 收敛 稳定性
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Empirical Line Method Using Spectrally Stable Targets to Calibrate IKONOS Imagery
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作者 XU Jun-Feng 《Pedosphere》 SCIE CAS CSCD 2008年第1期124-130,共7页
由使用幽灵似地稳定的目标,实验的线(EL ) 方法被测试改正多光谱在 Putuo 山上获得的 IKONOS 形象,浙江,中国。一系列刻度目标,随着时间的过去幽灵似地稳定,被选择建立线性预言的方程。随后,一系列幽灵似地稳定的确认目标被选择... 由使用幽灵似地稳定的目标,实验的线(EL ) 方法被测试改正多光谱在 Putuo 山上获得的 IKONOS 形象,浙江,中国。一系列刻度目标,随着时间的过去幽灵似地稳定,被选择建立线性预言的方程。随后,一系列幽灵似地稳定的确认目标被选择估计方程的精确性。并且,确认目标,随着时间的过去幽灵似地不稳定,被用来测试使用 EL 方法校准档案的遥远地察觉到的数据的可行性。为每个目标的地面反射大小用一个 ASD FieldSpec 分光辐射函数被做。Trimble GeoXT?与亚米精确性联合起来的 GPS 被用来精确地估计目标位置。为四个 IKONOS 乐队的线性回归方程被导出。为蓝、绿、红的乐队的决心的系数都比 0.9800 大,它为近红外线的乐队是 0.9697。合理结果能被使用幽灵似地稳定的目标获得,这被结束。 展开更多
关键词 土壤学 检测标准 校准度 检测方法
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改进的迈克尔逊干涉仪测量钠黄光双线波长差
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作者 陈海良 侯岩雪 +1 位作者 高静 张素红 《科学技术创新》 2024年第13期205-208,共4页
在迈克尔逊干涉仪实验教学及科学研究过程中发现齿轮经常脱扣的现象,这对测量结果产生了严重影响。本文中,我们将传统的齿轮咬合式迈克尔逊干涉仪改进为杠杆式迈克尔逊干涉仪,有助于避免齿轮咬合式迈克尔逊干涉仪中多个齿轮间容易脱扣... 在迈克尔逊干涉仪实验教学及科学研究过程中发现齿轮经常脱扣的现象,这对测量结果产生了严重影响。本文中,我们将传统的齿轮咬合式迈克尔逊干涉仪改进为杠杆式迈克尔逊干涉仪,有助于避免齿轮咬合式迈克尔逊干涉仪中多个齿轮间容易脱扣的现象。利用钠光灯照射杠杆式迈克尔逊干涉仪,观察到了明显的光拍干涉图样,测量了钠黄光双线波长差。钠黄光双线波长差的测量结果为0.5953±0.0054(nm)。本文的研究有助于提升迈克尔逊干涉仪装置的测量稳定性,实现在光谱定标、光学传感、生化检测等领域的长期稳定使用;有助于提升学生发现问题、解决问题的能力;以及有助于学生提升将不同科目知识相结合的能力。 展开更多
关键词 迈克尔逊干涉仪 钠黄光 光拍 波长差
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基于谱线-高阶累积量的调制识别研究与实现
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作者 张朝晖 孙臻烨 张欢 《自动化应用》 2024年第2期51-55,共5页
已发表的调制识别算法大多基于单一特征参数,识别种类较少,且往往很难在实际系统中布署。提出了一种基于谱线-高阶累积量的数字调制识别算法,该算法利用载波频率估计、符号速率估计、定时恢复、噪声功率估计等前处理手段,结合信号功率... 已发表的调制识别算法大多基于单一特征参数,识别种类较少,且往往很难在实际系统中布署。提出了一种基于谱线-高阶累积量的数字调制识别算法,该算法利用载波频率估计、符号速率估计、定时恢复、噪声功率估计等前处理手段,结合信号功率谱、二次方谱、四次方谱中的离散谱线和四阶归一化高阶累积量,可识别2ASK、4ASK、8ASK、2FSK、4FSK、8FSK、BPSK、QPSK、8PSK、OQPSK、MSK、16QAM、32QAM、64QAM、128QAM、256QAM 16种数字调制信号。基于该算法,设计并实现了一种数字调制识别处理系统,可实时识别上述16种调制信号。结果表明,该实时系统对大部分调制信号的识别准确率可达到99%以上,对8PSK、32QAM、128QAM等调制信号的识别准确率可达到94%以上。 展开更多
关键词 调制识别 谱线 高阶累积量 实时系统
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基于高光谱成像的桥梁混凝土表面露筋病害识别
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作者 周坤 彭雄 +3 位作者 钟新谷 张文辉 李千禧 赵超 《红外技术》 CSCD 北大核心 2024年第2期216-224,共9页
桥梁作为交通关键节点,承担与日俱增的交通流量压力,相当一部分桥梁尚未达到设计使用年限就出现较多的病害,技术状况不容乐观。高光谱成像运用光电技术检测物体对光谱波段信号的辐射和吸收情况,将该信号转换成图像和图形,可基于吸收峰... 桥梁作为交通关键节点,承担与日俱增的交通流量压力,相当一部分桥梁尚未达到设计使用年限就出现较多的病害,技术状况不容乐观。高光谱成像运用光电技术检测物体对光谱波段信号的辐射和吸收情况,将该信号转换成图像和图形,可基于吸收峰的位置和强度分析被测物体的物理性质和物质组成,因此本文提出基于高光谱成像的桥梁混凝土表面露筋病害识别方法。利用线阵高光谱相机集成匀速步进滑轨装置,形成高光谱成像测试系统,采集桥梁混凝土表面露筋病害图像;基于桥梁露筋病害高光谱图像谱线与空间特征,结合预处理——平滑滤波-多元散射校准(Savizky-Golay-Multivariate scattering calibration,SG-MSC)、特征空间变换——光谱导数法(First derivative,FD)、特征变量选择算法——竞争自适应重加权抽样(Competitiveadapativereweighted sampling,CARS),将原始光谱曲线数据经特征空间转换提取相应特征值并显示波段;以光谱曲线特征向量构建数据集,基于支持向量机形成露筋病害识别预测模型。以某跨江大桥为例,以高光谱成像测试系统对实际桥梁混凝土露筋病害进行识别,将原始光谱数据经平滑特征空间变换与特征提取后放大差异,将254个波段数据维度降低到23个波段数据,模型预测精度达到94.6%,对比可见光成像高光谱成像具有更高维度信息可有效表征物质属性,表明高光谱成像对复杂表面环境下的桥梁病害识别具有可行性和广泛应用前景。 展开更多
关键词 桥梁混凝土 高光谱成像 露筋病害 谱线特征 机器学习
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近Bohr速度129Xeq+离子入射Ta靶发射近红外光谱线
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作者 王益军 张颖 +9 位作者 张小安 周贤明 梅策香 梁昌慧 曾利霞 李耀宗 柳钰 向前兰 孟惠 张艳宁 《原子与分子物理学报》 北大核心 2024年第6期84-91,共8页
用动能一定的高电荷态^(129)Xe^(q+)(17≤q≤27)离子,分别入射洁净的Ta靶表面,测量中性化的激发态Xe原子从组态5p^(5)(^(2)P°_(3/2))nl退激到组态5p^(5)(^(2)P°_(3/2))ml’过程中辐射的近红外光谱线.实验结果表明:多激发态的... 用动能一定的高电荷态^(129)Xe^(q+)(17≤q≤27)离子,分别入射洁净的Ta靶表面,测量中性化的激发态Xe原子从组态5p^(5)(^(2)P°_(3/2))nl退激到组态5p^(5)(^(2)P°_(3/2))ml’过程中辐射的近红外光谱线.实验结果表明:多激发态的空心原子退激发射其特征光谱线,部分典型的跃迁按照阶梯方式退激.Xe原子发射的谱线的单粒子荧光产额和激发的Ta原子发射谱线的单粒子荧光产额随入射离子电荷态的增加而增加,其增加的趋势与入射离子携带的势能随电荷态增加的趋势一致.证明在近Bohr速度的能区,经典过垒模型是成立的. 展开更多
关键词 玻尔速度 高电荷态离子 经典过垒模型 近红外光谱线 空心原子
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脉冲放电等离子体光谱干扰机制及其修正方法研究
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作者 陈伟泽 喻子彧 +2 位作者 覃淮青 卢志民 姚顺春 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第2期347-353,共7页
为解决脉冲放电击穿颗粒流的等离子体光谱(PF-SIBS)中钨电极激发引起的谱线干扰问题,研究了基于等离子体信号探测优化的谱线干扰修正方法。搭建PF-SIBS测量实验系统,以化学纯石墨的颗粒流为研究对象,根据电极间等离子体产生和消亡过程... 为解决脉冲放电击穿颗粒流的等离子体光谱(PF-SIBS)中钨电极激发引起的谱线干扰问题,研究了基于等离子体信号探测优化的谱线干扰修正方法。搭建PF-SIBS测量实验系统,以化学纯石墨的颗粒流为研究对象,根据电极间等离子体产生和消亡过程、各特征谱线在等离子体内的分布情况以及各特征谱线信号强度在电极间的变化规律,解析了放电等离子体内各特征元素蒸发、解离和激发的过程,并据此优化光谱探测位置以减弱谱线干扰。研究结果表明:电子在阴极斑点生成,向阳极发射的过程中与电极金属、石墨颗粒流和电极间空气介质发生碰撞电离,产生更多的电子发射,从而形成并维持从阴极向阳极的放电通道。在阴极区域,高能电场产生的焦耳热促使阴极尖端钨金属蒸发溅射,膨胀产生的冲击使得颗粒和空气被排出阴极区域,钨金属的原子及电子占据在阴极区域;在放电通道中部,电子与密集的石墨颗粒流发生碰撞电离;在阳极区域,剩余的放电能量难以蒸发阳极金属,电子主要电离空气介质。可将阴极到阳极的区域划分为阴极金属激发区、中部颗粒激发区和阳极空气激发区。被电离的电极金属、石墨颗粒、空气介质的离子和中性原子占据各自的激发区域,形成等离子体并辐射出对应的特征谱线。从阴极到阳极的特征谱线强度变化呈现了与上述相同的结果,W 247.78 nm谱线强度在阴极区域较强并呈现逐步降低的趋势;C 247.86 nm谱线强度先增后减,在电极间距中心处达到最大;N 744.23 nm谱线强度逐步增强,在阳极尖端处达到最大。以C-W信号强度比作为C-W谱线干扰程度的评价指标,确定了最佳的光谱探测位置为距阳极0.5 mm处。相比于常见的光谱探测位置(电极间距中心),C-W信号强度比从1.200提升至1.348,C 247.86 nm的分峰拟合值与观测值之比从86.02%提升到94.93%,C-W谱线干扰效应显著降低。 展开更多
关键词 脉冲放电等离子体 谱线干扰 颗粒流 等离子体特性 在线监测
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高建筑物雷电光谱校正对通道温度反演的影响
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作者 王雪娟 化乐彦 +7 位作者 王炳浩 许伟群 吕伟涛 陈绿文 武斌 齐奇 马颖 杨静 《应用气象学报》 CSCD 北大核心 2024年第4期493-501,共9页
雷电光谱强度因受到大气衰减特性、光栅响应特性以及相机光电响应特性等影响,导致光谱定量分析中通道温度的反演存在误差。以1次高建筑物雷电回击光谱为例,考虑相机和光栅的仪器响应对其进行校正,对比校正前后的光谱结构和谱线强度,并... 雷电光谱强度因受到大气衰减特性、光栅响应特性以及相机光电响应特性等影响,导致光谱定量分析中通道温度的反演存在误差。以1次高建筑物雷电回击光谱为例,考虑相机和光栅的仪器响应对其进行校正,对比校正前后的光谱结构和谱线强度,并基于多谱线法利用1次电离的氮离子(NII)和中性氧原子(OI)谱线反演通道温度,分析光谱校正对通道温度反演的影响。结果显示:光谱校正后离子和中性原子谱线强度均明显增强,尤其可见光区域的连续谱强度明显增强,导致其谱线结构变化显著,而近红外区域的谱线结构变化不显著。利用校正后可见光区域的NII谱线和近红外区域的OI谱线反演通道温度时,线性拟合的决定系数均增大,反演准确度均得到提升。NII和OI谱线反演的通道温度平均值相比校正前分别降低4660 K和上升1540 K,且由OI谱线反演的通道温度低于由NII谱线反演的温度,说明它们分别对应雷电放电通道径向的不同区域。 展开更多
关键词 高建筑物雷电 光谱校正 多谱线法 温度
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Blackman-Nuttall窗FFT序列重构四谱线插值介损角测量方法
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作者 焦裕鹏 王玮 贾明娜 《中国测试》 CAS 北大核心 2024年第3期176-182,共7页
采用快速傅里叶变换(FFT)在非同步采样时会产生频谱泄露和栅栏效应,影响介质损耗角的测量精度。为提高介质损耗角的测量精度,该文提出并建立一种基于Blackman-Nuttall窗FFT序列重构的四谱线插值介损角测量方法,对采样信号加Blackman-Nut... 采用快速傅里叶变换(FFT)在非同步采样时会产生频谱泄露和栅栏效应,影响介质损耗角的测量精度。为提高介质损耗角的测量精度,该文提出并建立一种基于Blackman-Nuttall窗FFT序列重构的四谱线插值介损角测量方法,对采样信号加Blackman-Nuttall窗进行FFT获得离散频谱序列,通过五点变换重构离散频谱序列,然后对重构后的序列进行四谱线插值修正得到电压和电流信号的基波相位,最后由两者的基波相位得到介质损耗角。通过在频率变化、采样点数变化、初始相位变化、直流分量变化、谐波分量变化和不同信噪比的噪声下仿真实验,表明该方法具有较高的介质损耗角测量精度。在与已用加窗傅里叶变换法相比,该方法运算量小、测量精度高,适用于对介质损耗角的精确测量。 展开更多
关键词 快速傅里叶变换 Blackman-Nuttall窗 五点变换 四谱线插值 介质损耗角
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Humidity-Induced Spectral Shift in a Cross-DispersionEchelle Spectrometer and Its Theoretical Investigation 被引量:1
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作者 LIU Ke-ling HUANG Mao Hieftje Gary M 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2010年第9期2555-2559,共5页
The relationship between ambient relative humidity H and the position shift of a spectral line was investigated both experimentally and theoretically.An echelle-based ICP emission spectrometer equipped with a CID dete... The relationship between ambient relative humidity H and the position shift of a spectral line was investigated both experimentally and theoretically.An echelle-based ICP emission spectrometer equipped with a CID detector was used for experimental verification of the derived model.The shift of a spectral line is quantitatively described by two defined spectral shift functions: Δλx(x,λ,H)(in the x direction of the CID detector) and Δλy(y,λ,H)(in the y direction of the CID detector).Experimental results indicate that Δλx(x,λ,H) does not change with a variation in ambient relative humidity, but Δλy(y,λ,H) does.A spectral shift equation,i.e.an empirical second-order polynomial equation,can be used to describe the relationship between Δλy(y,λ,H) and H.Based on the classical dipole model,classical mechanics and electrodynamics the empirical spectral-shift equation involving Δλy(y,λ,H) and H was theoretically deduced.The theoretical result is in good agreement with the experimental findings.The theoretical results indicate that the coefficients of the empirical spectral-shift equation are related to the basic physical parameters of materials and the geometric configuration of the echelle CID ICP-AES,and also provide physical meaning to the coefficients of the empirical shift equation obtained experimentally. 展开更多
关键词 Emission spectrometry Position shift of a spectral line spectral-shift equation
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