高分辨率初始光电子能谱由真空紫外激光速度——映射图像的方法

通过采用真空紫外(VUV)激光速度-地图成像-TPE(真空紫外VMI-TPE)方法获得了高分辨率初始光电子(TPE)氯苯(C₆H₅Cl(X¹A₁))的光谱,炔丙基自由基(C₃H₃(X²B₁))和烯丙基(C₃H₅(X²A₁)). 观察到的真空紫外VMI-TPE方法的光电子能量分辨率在1~2 cm^-1,可以和在真空紫外激光脉冲场电离光电子(VUV-PFI-PE)的测量媲美. 类似真空紫外PFI-PE测量,真空紫外VMI-光电子(真空紫外VMI-PE)和真空紫外VMI-TPE测量能量分辨率依赖于直流电场在光电离区加速电子. C₆H₅Cl和C₃H₃的电离初始值的降低为F的函数表示Stark偏移校正为VUV-VMI-TPE测量由-3.1√F管辖,这是半经典预测值-6.1√F的一半. 我们还测量C₆H₅Cl和C₃H₅的真空紫外光能量的真空紫外VMI-PE谱接近其电离初始值. 在VUV-VMI-PE测量中观察到的C₃H₅⁺阳离子振动谱和振动级数,nv₇⁺(n=0~3). 真空紫外VMI-TPE可以实现更高的实验灵敏度和类似真空紫外PFI-PE测量的能量分辨率,使真空紫外VMI-TPE法成为高分辨率真空紫外PFI-PE测量一个很好的替代.     

第Ⅱ种强度不等的两态叠加多模叠加态光场的等阶N次方H压缩1腔模总数与压缩阶数两者之积取偶数的情形

利用多模压缩态理论研究了第种强度不等的非对称两态叠加多模叠加态光场|Ψ_Ⅱ^(ab)〉q的等阶N次方H压缩特性.结果发现:1)当腔模总数q与压缩阶数N的乘积取偶数,亦即qN=2p时,无论p=2m(m=1,2,3,…,…),还是p=2m+1(m=0,1,2,3,…,…),只要各模的初始相位差(φ_j^(a)-φ_j^(b))、态间的初始相位差(θ_nq^(aR)-θ_nq^(bR))及光子干涉项的幅度 1R_j^(a)R_j^(b)等分别满足一定的条件,则态|Ψ_||^(ab)〉q的第一和第二正交分量总可分别呈现出周期性变化的等阶N次方H压缩效应.2)当qN=2p且p=2m+1(m=0,1,2,3,…,…)时,若构成态|Ψ_Ⅱ^(ab)〉q的两个不同的量子光场态中各对应模的强度(即平均光子数)和初始相位相等,亦即R_j^(a)=R_j^(b)和φ_j^(a)=φ_j^(b)(j=1,2,3,…,q),则态|Ψ_Ⅱ^(ab)〉q可呈现出“等阶N次方H压缩简并”现象.     

第Ⅱ种强度不等的非对称两态叠加多模叠加态光场的偶数阶等阶N次方Y压缩

本文构造了由多模复共轭相干态的相反态|{-Z_j^(a)*}>_q与多模虚共轭相干态的相反态|{-iZ_j^(b)*}>_q这两者的线性叠加所组成的第Ⅱ种强度不等的非对称两态叠加多模叠加态光场|Ψ_Ⅱ^(ab)>_q,利用多模压缩态理论研究了态|Ψ_Ⅱ^(ab)>_q的任意偶数阶等阶N次方Y压缩特性.结果发现:1)在压缩阶数N取偶数,即N=2p的条件下,无论p=2m(m=1,2,3,…,…),还是p=2m+1(m=0,1,2,3,…,…),只要构成态|Ψ_Ⅱ^(ab)>_q的两个不同的量子光场态中各对应模的强度(即平均光子数)和初始相位都不相等,亦即R_j^(a)≠R_j^(b)和φ_j^(a)≠φ_j^(b)(j=1,2,3,…,q),并且 ,则当满足一定的量子化条件(或者在一些闭区间内连续取值)时,态|Ψ_Ⅱ^(ab)>_q总可呈现出周期性变化的、任意偶数阶的等阶N次方Y压缩效应.2)在N=2p且p=2m+1(m=0,1,2,3,…,…)的条件下,若R_j^(a)=R_j^(b)和φ_j^(a)=φ_j^(b)(j=1,2,3,…,q),态|Ψ_Ⅱ^(ab)>_q则可呈现出等阶N次方Y压缩简并现象.     

Stereochemical studies of oligomers XXIX. Reinvestigation of the structure of N-m-tolyl phthalimide

C₁₅H₁₁NO₂, Mr 237.3, monoclinic, space groupC _c, a=8.539(2),b=19.865(4),c=7.599(2)?,β=111.44(2)°,V=1199.8 ?³,Z=4,D _c=1.31 gcm⁻³,λ(CuKα)=1.5418 ?,μ=6.74cm⁻¹,F(000)=496, room temperature. The structure was solved by direct methods with SHELX-86 and refined down to agreement valueR=0.046 for 1117 reflections above 2σ(I). The angle between the plane of the phthalimide group, which shows a little bent [1.2(2)°] between its two rings, and the tolyl group is 56.1(1)°. The packing of the molecules is stabilized by van der Waal’s forces only. Part XXVIII: Bocelli and Rizzoli (1990)     

多模叠加态光场|ψ5(3)〉q中广义磁场4m次方Y压缩

构造了由多模复共轭相干态|{Z_j^*}〉_q、多模复共轭相干态的相反态|{-Z_j^*}〉_q以及多模虚相干态|{iZ_j^*}〉_q的线性叠加所组成的第Ⅴ类三态叠加多模叠加态光场|ψ₅⁽³⁾〉_q.利用多模压缩态理论研究了态|ψ₅⁽³⁾〉_q中广义磁场分量的等幂次N次方Y压缩特性.结果发现:当压缩次数N=2p且p=2m(m=1,2,3,…,…)时,只要各模的初始相位φ_j(j=1,2,…,…,q)、态间的初始相位差(θ₁-θ₂)、(θ₁-θ₃)和(θ₂-θ₃)以及受各模的初始相位φ_j调制的各单模相干态光场的平均光子数之和 等分别满足一定的取值条件,则态|ψ₅⁽³⁾〉_q的广义磁场分量就可呈现出周期性变化的广义非线性等幂次4m次方Y压缩效应.     

SiO2分子的基态(X1A1)结构与分析势能函数

应用群论及原子分子反应静力学方法推导了SiO₂分子的电子态及其离解极限，采用B3P86方法，在6-311G^**水平上,优化出SiO₂基态分子稳定构型为单重态的C_2V构型，其平衡核间距R_e=R_Si—O=0.1587 nm,∠OSiO＝111.2°,能量为-440.4392 a.u..同时计算出基态的简正振动频率:对称伸缩振动频率ν(B₂)=945.4cm^-1，弯曲振动频率ν(A₁)=273.5 cm^-1和反对称伸缩振动频率ν(A₁)=1362.9cm^-1.在此基础上，使用多体项展式理论方法，导出了基态SiO₂分子的全空间解析势能函数，该势能函数准确再现了SiO₂(C_2V)平衡结构.     

Nd掺杂对Bi4Ti3O12铁电薄膜的微结构和铁电性能的影响

利用溶胶-凝胶法在Pt/Ti/SiO₂/Si(100)衬底上制备了Nd掺杂Bi₄Ti₃O₁₂(Bi_4-xNd_xTi₃O₁₂, x=0.00,0.30,0.45,0.75,0.85,1.00,1.50)铁电薄膜样品.研究了Nd掺杂对Bi₄Ti₃O₁₂薄膜的微结构和铁电性能的影响.研究结果表明:Nd掺杂未改变Bi₄Ti₃O₁₂薄膜的基本晶体结构.在掺杂量x<0.45时,Nd³⁺只取代类钙钛矿层中的A位Bi³⁺.当x=0.45时,样品剩余极化强度达最大值,在270kV·cm^-1的电场下为32.7μC·cm^-2.掺杂量进一步增加时,结构无序度开始明显增大,Nd³⁺开始进入(Bi₂O₂)²⁺层,削弱其绝缘层和空间电荷库的作用,导致材料剩余极化逐渐下降.当掺杂量x达到1.50时,掺杂离子最终破坏(Bi₂O₂)²⁺层的结构,材料发生铁电-顺电相变.     

Studies in molecular structure,symmetry and conformation—Part XIV. Crystal and molecular structure of L-isoleucine hydrochloride monohydrate form II

The crystal structure of a new form of L-isoleucine hydrochloride monohydrate C₆H₁₃O₂NHClH₂O (termed form II) has been determined using three-dimensional photographic data. This differs conformationally from the hydrochloride derivative (termed form I, Trommel and Bijvoet 1954) reported earlier. The crystal belongs to the orthorhombic space group P2₁2₁2₁ with cell dimensions,a=5.87±0.01,b=24.77±0.02 andc=6.85±0.01 ? and four molecules per cell,ρ _obs=1.240 g/cm³,ρ _cal=1.238 g/cm³,μ for CuKa=32.6 cm⁻¹. Contribution No. 420 from the Department of Crystallography and Biophysics, University of Madras, Madras 600025.     

GeO2-Bi2O3-MOx(MOx=WO3, BaO)玻璃近红外超宽带发光的研究

用高温熔融法制备了(99.5-χ) GeO₂-χBaO-0.5Bi₂O₃(χ=3, 6, 9mol%)与(99.5-φ)GeO₂-φWO₃-0.5Bi₂O₃(φ=3，6，9mol%)玻璃，测定了样品的发射光谱(800nmLD激发)、吸收光谱、荧光衰减和差热曲线.实验结果表明，在GeO₂-WO₃-Bi₂O₃系统玻璃中，随着WO₃含量的增加，在1260nm处的发光强度增强，荧光半高宽(FWHM)增宽，荧光寿命增长，而且玻璃的吸收边带发生明显的红移；在GeO₂-BaO-Bi₂O₃系统玻璃中，随着BaO含量的增加，玻璃在1290nm处发光强度增强，FWHM增宽，荧光寿命增长，吸收边带也有明显的红移.从吸收边带发生红移的情况，结合发射光谱和荧光衰减曲线特性，我们推断玻璃样品在近红外的宽带发光可能由Bi⁵⁺离子所引起.从荧光特性估算了玻璃的σ_p×τ和σ_p×Δλ值，这些玻璃均具有较小的σ_p×τ和较大的σ_p×Δλ特性，说明GeO₂-Bi₂O₃-MO_x(MO_x=WO₃, BaO) 系统玻璃是研制成近红外(O到S波段)超宽带光纤放大器的良好材料.     

一种新型的两态叠加多模Schrödinger猫态光场的等阶N次方Y压缩

本文根据量子力学的线性叠加原理,构造了由多模(即q模)相干态的相反态|{-Z_j}〉q及多模虚相干态|{Z_j}〉q这两者的线性叠加所组成的一种新型的多模Schrdinger猫态光场|Ψ⁽²⁾〉q,利用新近建立的多模压缩态理论,研究了态|Ψ⁽²⁾〉q的N次方Y压缩效应。结果发现:①当压缩阶数N=2p且p=2m(m=1,2,3,…,…)时,态|Ψ⁽²⁾〉q总是恒处于N-Y最小测不准态;②当压缩阶数N=2p且p=2m+1(m=0,1,2,3,…,…)时,如果各模的初始相位φ_j,态间的初始相位差θ_pq^(I)-θ_nq^(R)以及各单模相干态光场的平均光子数之总和 等满足一定的量子化条件,则态|Ψ⁽²⁾〉q可呈现出周期性变化的、任意阶的N次方Y压缩效应;③当压缩阶数N=2p′+1时,无论p′=2m(m=0,1,2,…,…)还是p′=2m+1(m=0,1,2,3,…,…),只要各模的初始相位φ_j满足一定的量子条件,则当两态叠加几率幅满足r_pq^(I)=r_nq^(R)时,态|Ψ⁽²⁾〉q就恒处于N-Y测不准态,始终不呈现N-Y最小测不准态和N次方Y压缩;而当r_pq^(I)≠r_nq^(R)时,态|Ψ⁽²⁾〉q始终不呈现N-Y测不准态、N-Y最小测不准态和N次方Y压缩效应。     

基于激光吸收光谱技术天然气管道泄漏定量遥测方法的研究

报道了基于激光吸收光谱学原理的天然气管道泄漏移动遥测技术,通过模拟天然气泄漏实验, 分析了移动遥测的关键技术问题.为了定量遥测天然气管道微量泄漏,引入一个和剩余幅度调制(RAM) 等值反相的信号对偏差进行补偿,降低RAM对谐波信号的影响,提高系统检测灵敏度. 针对遥测回波吸收光谱特征,提出了改进软阈值小波去噪法,就提高系统信噪比而言, 比传统软阈值去噪法高2倍多,同时对二次谐波(2f)信号形状也有很好的保留,通过探测限计算, 系统移动遥测灵敏度达到80 ppm/m.     

Calibration-free wavelength modulation spectroscopy for gas concentration measurements under low-absorbance conditions

<正>We derive the expressions of the first and second harmonic signals on the basis of absorption spectral and lock-in theories,and determine the gas concentration according to the ratio of second and first harmonic signals.It is found that the X and Y components of the harmonic signals are influenced by the phase shift between the detection and reference signal,and the phase shift can be any value in a range from 0 to 2π,which is different from the results obtained previously.Meanwhile,an additional item caused by the residual amplitude modulation will make a great contribution to the second harmonic signal,and may not be neglected under low absorbance conditions.Theoretical analysis indicates that subtracting back-ground signal from the second harmonic signal can remove the influence of this item,and can improve the measurement accuracy of gas concentration.On this basis,we select the transition of CO₂ at 6527.64 cm^-1 to analyse the approximation errors during the derivation by numerical simulation and then measure the CO₂ concentration under low absorbance conditions,with absorbance varying from l%o to 6‰.     

Temperature sensitivity and noise of an HTSC Josephson detector on a sapphire bicrystal substrate at 77 K

In YBa₂Cu₃O_{7 − x} films grown on sapphire bicrystal substrates, the Josephson junctions are prepared based on artificial grain boundaries formed by the turn of the crystal lattices about the [100] axis. The films are deposited by the laser ablation method on the buffer CeO₂ layer. The critical film temperature reaches 88.5 K with a transition width of 1.5 K. Junctions from 2 to 3-μ m wide are integrated into the planar log-periodic antennas and their characteristics are measured at 77 K. The characteristic voltage I _c R _n reaches 570 μV. With exposure to external radiation at a frequency of 113 GHz, the Shapiro steps were observed on the current-voltage characteristic. The temperature sensitivity of this detector placed in a quasi-optical receiving unit is measured. At the modulation of the input radiation temperature 77 K/300 K, a response of more than 200 nV is observed at the detector output. At the modulation frequency, intrinsic noise is about 1 nV/Hz^1/2, which corresponds to a temperature resolution of 1 K. Original Russian Text ? M. Tarasov, E. Stepantsov, A. Kalabukhov, M. Kupriyanov, D. Winkler, 2007, published in Pis’ma v Zhurnal éksperimental’noĭ i Teoreticheskoĭ Fiziki, 2007, Vol. 86, No. 11, pp. 828–831.     

High-resolution Reflection Spectroscopy of Cs D2 Line Studied by High-order-harmonic Detection

In this paper, by numerical analysis the relationship of the modulation broaden index with modulation index using high-order-harmonic detection is investigated. Using the voltage modulation the 2f,4f and 6f harmonic signals about the reflection spectroscopy of 6S1/2(F=4)→6P3/2 transition of the cesium D2 line are also be measured. The experimental results are in good agreement with the theoretical predictions. It is found that narrower line-width can be achieved by higher-harmonic detection than the line-width detected by direct absorption when the modulation index is smaller than 1.81, 2.98 and 4.14 for 2f, 4f, and 6f signals, respectively.     

High-resolution Reflection Spectroscopy ofCs D_2 Line Studied by High-order-harmonic Detection

In this paper, by numerical analysis the relationship of the modulation broaden index with modulation index using high-order-harmonic detection is investigated. Using the voltage modulation the 2f,4f and 6f harmonic signals about the reflection spectroscopy of 6S1/2(F = 4) →6P3/2 transition of the cesium D2 line are also be measured. The experimental results are in good agreement with the theoretical predictions. It is found that narrower line-width can be achieved by higher-harmonic detection than the line-width detected by direct absorption when the modulation index is smaller than 1.81, 2.98 and 4.14 for 2f, 4f, and 6f signals, respectively.     

Influence of the distance between two voltage contacts on giant magneto-impedance of Co-based amorphous wires

The Co₇₅ Fe_4.2Si₈B₁₂Nb_0.8 amorphous wires of 30 μ m in diameter are produced by melt extraction and annealing at 450 oC for 20 min in vacuum with a longitudinal or transverse field of 40 kA/m. Distances between the two voltage contacts of 6, 5, 4 and 2 mm are obtained by moving the two voltage contacts towards the centre of the sample at the same time. Results indicate that magneto-impedance response is dependent on the distance significantly. As distance decreases from 6 to 2 mm, △Z/Z reduces from 609% to 95% and giant magneto-impedance (GMI) profiles change from two-peak to single-peak. Besides, field sensitivity improves from 0.47%/(A/m) to 0.76%/(A/m) when the single-peak GMI just appears. It is therefore concluded that actual measurements can be made comparable only by taking into account the influence of distance between two voltage contacts for a magneto-impedance measurement.     

非标定波长调制吸收光谱气体测量研究

为消除可调谐激光调制吸收光谱气体测量技术对于标定过程的依赖,研究了二次谐波信号的非标定波长调制气体测量方法.通过对测量的二次谐波线型进行分析,给出相同工况下二次谐波模拟信号,并利用测量与模拟二次谐波信号进行线性拟合直接计算气体浓度.实验室内采用非标定波长调制气体测量方法,利用 6336.24 cm^-1处特征吸收谱线对10 cm长气体吸收池内的CO₂进行了测量.结果表明,非标定波长调制气体测量方法可适应各种不同条件,适合于现场气体在线测量.当调制系数在1.8—3. 关键词： 波长调制 二次谐波 吸收光谱 半导体激光器     

Higher harmonic thermal wave detection in thermoreflectance microscopy with combined electrical and optical heating

Insulating lines and channels prepared by focused ion beam implantation on SIMOX wafers have been investigated by thermally modulated optical reflectance microscopy using optical and electrical excitation. Continuous hot lines and hot spots can be visualized by modulated electrical heating, whereas insulating lines forming channels can be imaged only with simultaneous optical and electrical excitation. Three different schemes have been investigated for the combined excitation: (i) optical modulation with additional DC voltage, (ii) optical and electrical pumps modulated at the same frequency with the detection effected at higher harmonics and (iii) two different modulation frequencies used for optical and electrical excitation with the detection effected at sum and difference frequencies. When detecting at higher frequencies, best contrast for the observation of the insulating lines adjacent to a channel is achieved by recording the modulated reflectance signal at the fourth harmonic 4f where f is the modulation frequency of the optical and electrical pump. The observed contrast enhancement of the double excited thermoreflectance signal is found to be mainly of a thermal origin.     

Reconstruction of the first-derivative EPR spectrum from multiple harmonics of the field-modulated continuous wave signal

Selection of the amplitude of magnetic field modulation for continuous wave electron paramagnetic resonance (EPR) often is a trade-off between sensitivity and resolution. Increasing the modulation amplitude improves the signal-to-noise ratio, S/N, at the expense of broadening the signal. Combining information from multiple harmonics of the field-modulated signal is proposed as a method to obtain the first derivative spectrum with minimal broadening and improved signal-to-noise. The harmonics are obtained by digital phase-sensitive detection of the signal at the modulation frequency and its integer multiples. Reconstruction of the first-derivative EPR line is done in the Fourier conjugate domain where each harmonic can be represented as the product of the Fourier transform of the 1st derivative signal with an analytical function. The analytical function for each harmonic can be viewed as a filter. The Fourier transform of the 1st derivative spectrum can be calculated from all available harmonics by solving an optimization problem with the goal of maximizing the S/N. Inverse Fourier transformation of the result produces the 1st derivative EPR line in the magnetic field domain. The use of modulation amplitude greater than linewidth improves the S/N, but does not broaden the reconstructed spectrum. The method works for an arbitrary EPR line shape, but is limited to the case when magnetization instantaneously follows the modulation field, which is known as the adiabatic approximation.     

不同加热机制产生的超热电子的相干渡越辐射谐波研究

利用不同加热机制产生的超热电子所导致的相干渡越辐射(CTR)在谐波分量强度比上的不同，给出了区分飞秒激光等离子体相互作用产生超热电子过程中的主要与次要加热机制的一种可能方法.得到了加热周期不同的加热机制所产生超热电子的比例与CTR谐波分量的二倍频和一倍频的强度比之间的具体关系式.如果在实验上测到此谐波分量强度比，就可以推出不同加热机制在加热过程中所起作用的大致比例关系.另外，CTR谐波分量的强度比还与超热电子的温度、实验上所使用靶的厚度有一定依赖关系，对此作了较为详细的讨论. 关键词： 相干渡越辐射 超热电子 加热机制