共查询到20条相似文献,搜索用时 109 毫秒
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《光谱学与光谱分析》2017,(11)
在核燃料后处理流程中,需对工艺中的铀浓度进行准确测量。利用X射线管照射铀溶液,通过测量铀的L边界X射线透射谱确定铀浓度。文章设计了铀的L边界X射线透射谱测量系统。通过配制1~200g·L~(-1)铀标准溶液,建立铀浓度测量工作曲线,并对系统的精密度、准确度和稳定性进行测试。结果表明,铀浓度测量工作曲线线性拟合参数R2=0.999 9;系统对57.004g·L~(-1)铀溶液测量精密度为0.21%,对38.255g·L~(-1)铀溶液测量相对误差为0.32%;对2.236g·L~(-1)铀溶液进行连续测量,99.67%数据落在μ±3s。 相似文献
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瑞奇-康芒法是用小口径干涉仪检测大口径平面镜的主要方法之一。通过分析瑞奇-康芒法中球面参考镜半径、平面镜位置和瑞奇角误差对测量精度的影响,给出了3个参数的选择方法。针对瑞奇-康芒法测量时误差分离导致的测量效率低的问题,提出适用于加工过程的快速瑞奇-康芒测量法,仿真模拟该方法下被测平面镜位置、角度等定位误差对测量结果的影响,并设计实验对比验证。该方法与直测法测量间的最大偏差峰-谷值(PV)为0.0151μm,均方根(RMS)为0.0036μm,能够有效满足加工过程中面形快速测量需求。 相似文献
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本文提出了一种采用迈克尔逊干涉仪方法测量压电振子表面振动位移分布的简单方法。当其中一支光路引入一低频相位调制,可使测量结果不受环境机械振动和声噪声的干扰(包括带动微动台移动的马达机械振动和声噪声),因而可进行一维自动测量。当自动测量时,位移振幅一般需大于0.1A,当进行定点精密绝对测量时,最小可测位移为5×10~(-2)-5×10~(-3)A,最后给出了几种压电振子的测量结果。 相似文献
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为了提高发光及显示器件光电特性测量实验的智能化程度,减小人为误差,并考虑工作温度对其光电特性的影响,设计了一种能够自动、同步测量发光体亮度、温度、伏安特性和寿命的系统。系统主要由LS-110型亮度计、GPD-3303型电源、自制的温度测量模块及测量软件四部分组成。基于实验室虚拟仪器工程平台,利用亮度计对器件的亮度进行测量,利用单片机和温度传感器对器件的温度进行测量,通过上位机程序控制电源步进输出、读取实际输出电流值和电压值,并将采集到的数据发送到上位机,实时绘制出了亮度-电压、电流-电压、温度-电压、亮度-温度、电流-温度、亮度-电流特性曲线。系统目前可以同时对器件的亮度、温度和伏安特性进行自动测量和直观显示,并且具备自动保存数据和图像的功能,实现了发光及显示器件光电特性测量的智能化,具有综合性强、精确度及自动化程度高、操作简易等特点。 相似文献
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《Physics letters. [Part B]》2008,663(4):418
Rare decay modes , J/ψ→D−π++c.c., and are searched for using events collected with the BESII detector at the BEPC. No signal above background is observed. We present upper limits on the branching fractions of , B(J/ψ→D−π+)<7.5×10−5, and at the 90% confidence level. 相似文献
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V. I. Arkhipenko S. M. Zgirovskii L. V. Simonchik G. F. Stel'makh 《Journal of Applied Spectroscopy》2004,71(1):107-114
A light source with a thermoionic cathode has been investigated in helium at atmospheric pressure; the spectral radiance of the light source in the range 200–800 nm and the cathode temperature (3510 K) have been determined. Its employment as a light source in absorption spectroscopy for determination of the concentration of triplet and singlet metastable helium atoms in an atmospheric-pressure glow discharge has been demonstrated. The total concentration of metastable atoms was 3.5·1013 cm–3. 相似文献
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M.J. Dick P.M. Sheridan J.-G. Wang S. Yu P.F. Bernath 《Journal of Molecular Spectroscopy》2006,240(2):238-243
The state of CaOH was investigated using optical–optical double resonance spectroscopy. A combined least-squares fit of the double resonance transition data along with optical transition data and the millimeter-wave pure rotational data of the state was performed using an effective Hamiltonian. The spin–rotation constant was determined for the state for the first time. An analysis of these constants showed that the Ca–O bond length and spin–rotation parameter of the state have the smallest values of all the observed 2Σ+ states of CaOH. This evidence suggests the assignment of the state as arising from a Ca+ atomic orbital of mainly 5sσ character. This atomic orbital assignment was shown to be consistent with both previous work on CaF and recent theoretical calculations on CaOH. 相似文献
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T. Matsui A.S.-C. Cheung K. Yoshino W.H. Parkinson J.E. Murray T. Imajo 《Journal of Molecular Spectroscopy》2003,219(1):45-57
The photoabsorption spectrum of the O2 Schumann-Runge bands was measured with resolution comparable to the Doppler widths by using the VUV Fourier transform spectrometer from Imperial College, London, combined with synchrotron radiation as a continuum light source at the Photon Factory, KEK, Japan. The analysis of the (12,0)-(17,0) bands of the Schumann-Runge system provides accurate rotational line positions as well as the line intensities from 185 to 175 nm. Molecular constants of the levels of the state have been determined. The (v′,0) band oscillator strengths were determined as 2.38, 2.62, 2.70, 2.66, 2.40, and 2.12×10−5 for the bands from v′=12 to 17, respectively. 相似文献
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The tree-level contributions to the rare decays , , and are analyzed and compared to those occurring in , , and . It is shown that these purely long-distance contributions, arising from the exchange of a charged lepton, can be significant in B+ decays for an intermediate τ, potentially blurring the distinction between the modes used to extract B+→τ+ντ and those used to probe the genuine short-distance and FCNC transitions. Numerically, the tree-level contributions are found to account for 98%, 12% and 14% of the total , , and rates, respectively. 相似文献
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Anomalous dimension and higher conserved charges in the sl(2) sector of SYM for generic spin s and twist L are described by using a novel kind of non-linear integral equation (NLIE). The latter can be derived under typical situations of the SYM sectors, i.e. when the scattering need not depend on the difference of the rapidities and these, in their turn, may also lie on a bounded range. Here the non-linear (finite range) integral terms, appearing in the NLIE and in the dimension formula, go to zero as s→∞. Therefore they can be neglected at least up to the O(s0) order, thus implying a linear integral equation (LIE) and a linear dimension/charge formula respectively, likewise the ‘thermodynamic’ (i.e. infinite spin) case. Importantly, these non-linear terms go faster than any inverse logarithm power (lns)−n, n>0, thus extending the linearity validity. 相似文献
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Y. T. Lie 《Applied Physics A: Materials Science & Processing》1973,2(6):297-302
A sliding spark over solid xenon has been developed with the object to serve as a vacuum-ultraviolet light source for the photoionization of gases, especially hydrogen and inert gases. An intensity of 1·1012 Watt/cm3 sr at 800 Å has been observed, lasting about 5 μsec. The emitting area was approximately 1.6 cm2. This light source has been used to irradiate a test gas of xenon at 0.4 m Torr. An electron density of 2·1012 cm?3 was detected at a distance of 80 cm with an 8 mm microwave interferometer. 相似文献
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《Physics letters. [Part B]》2009,679(4):321-329
We present the first measurement of photoproduction of J/ψ and of two-photon production of high-mass e+e− pairs in electromagnetic (or ultra-peripheral) nucleus–nucleus interactions, using Au + Au data at . The events are tagged with forward neutrons emitted following Coulomb excitation of one or both Au nuclei. The event sample consists of 28 events with me+e−>2 GeV/c2 with zero like-sign background. The measured cross sections at midrapidity of and for me+e−[2.0,2.8] GeV/c2 have been compared and found to be consistent with models for photoproduction of J/ψ and QED based calculations of two-photon production of e+e− pairs. 相似文献
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A. S. Alekseev A. V. Efimov V. I. Chukharev H. Lemmetyinen 《Bulletin of the Lebedev Physics Institute》2010,37(5):136-140
In the three-layer Langmuir-Schaefer films consisting of a monolayer of donor-acceptor phtalocyanine-fullerene dyad molecules (Bu 3 ProM 2 F) and two layers of poly(3-hexylthiophene) (PHT), placed into an electrochemical cell, the electric current resulted from optical excitation of sampleswas measured with no external voltage source. Samples were excited by the xenon lamp light passed through amonochromator or by a source simulating the solar spectrum. It was shown that the current density in samples reached 40–50 µA/cm2 in the latter case. Current-voltage characteristics of samples were measured. Photovoltaic responses of three-layer structures were studied by the time-resolved Maxwell displacement charge method. The preferred orientation of dyad molecules in the film was demonstrated. 相似文献