Spectroscopically determined potential energy surfaces of the H2O, H2O, and H2O isotopologues of water

Adiabatic potential energy surfaces (PESs) for three major isotopologues of water, H₂¹⁶O, H₂¹⁷O, and H₂¹⁸O, are constructed by fitting to observed vibration-rotation energy levels of the system using the nuclear motion program DVR3D employing an exact kinetic energy operator. Extensive tests show that the mass-dependent ab initio surfaces due to Polyansky et al. [O.L. Polyansky, A.G. Császár, S.V. Shirin, N.F. Zobov, P. Barletta, J. Tennyson, D.W. Schwenke, P.J. Knowles, Science 299 (2003) 539-542.] provide an excellent starting point for the fits. The refinements are performed using a mass-independent morphing function, which smoothly distorts the original adiabatic ab initio PESs. The best overall fit is based on 1788 experimental energy levels with the rotational quantum number J = 0, 2, and 5. It reproduces these levels with a standard deviation of 0.079 cm⁻¹ and gives, when explicit allowance is made for nonadiabatic rotational effects, excellent predictions for levels up to J = 40. Theoretical linelists for all three isotopologues of water involved in the PES construction were calculated up to 26 000 cm⁻¹ with energy levels up to J = 10. These linelists should make an excellent starting point for spectroscopic modelling and analysis.     

蝶形微带天线的谐振频率与双频设计

介绍了蝶形微带贴片天线的一种双频设计。基于变分法导出蝶形微带天线谐振频率闭式计算公式，采用矩量法对天线进行了全波分析，该法比已有方法具有更广的适用范围。最后对设计结果进行了加工和测试，测试结果与实验结果相当吻合，证实了数值分析与设计方法的有效性。     

顺序等离子体光谱技术测定煤飞灰中常量,少量和微量元素

本文采用顺序等离子体光谱技术测定煤飞灰中主要成份（Ｃａ、Ｍｇ、Ｆｅ、Ａｌ、Ｓｉ、Ｎａ、Ｋ、Ｔｉ）及微量成份（Ｃｕ、Ｓｃ、Ｖ、Ｎｉ、Ｂｅ、Ｍｎ）。用扫描光谱法研究了分析线的选择和光谱背景的扣除。试样用密封罐混酸溶解。测定煤飞灰标准样品ＮＢＳ１６３３ａ的结果与标准值一致。方法用于测定新制备的煤飞灰标准参考物。     

CO2 line intensity FTS measurements with 1% assumed accuracy in the 1.5-1.6 μm spectral range

Using Fourier-transform spectra and a multispectrum fitting procedure, 124 absolute line intensities of ¹²C¹⁶O₂ are obtained for the cold band 30011-00001 and the hot band 01131-01101 between 6460 and 6950 cm⁻¹. Vibrational transition dipole moments squared and Herman-Wallis coefficients are reported for each band. Cross comparisons made with previous experimental results and with data available in the HITRAN and Carbon Dioxide Spectroscopic Databank (CDSD), bring some confidence on the good level of accuracy of the present results. Motivated by the demanding needs of some atmospheric experiments dedicated to the survey of the carbon cycle, an additional evaluation of potential absolute line intensity measurement limit is also performed on recently published carbon dioxide absolute line intensity independent measurements. These are obtained in two different laboratories on the bands 30013-00001 and 30012-00001 both located in the 1.6 μm spectral window. It is shown that Fourier-transform experimental CO₂ line intensity determination is approaching the challenging required figure of about 0.3% accuracy needed for the survey of the atmospheric carbon cycle.     

The absorption spectrum of phosphine (PH3) between 2.8 and 3.7 μm: Line positions, intensities, and assignments

Over 8000 line positions and intensities of phosphine (PH₃) at 3 μm have been measured at 0.0115 cm⁻¹ resolution with the McMath-Pierce Fourier Transform spectrometer at Kitt Peak. The observed line intensities ranged from 4.13 × 10⁻⁶ to 4.69 × 10⁻² cm⁻² atm⁻¹ at 296 K, for line positions between 2724.477 and 3601.652 cm⁻¹. This region spans eight interacting vibrational states: 3ν₂ (2940.8 cm⁻¹), 2ν₂ + ν₄ (3085.6 cm⁻¹), ν₂ + 2ν₄ (3214.9 cm⁻¹), ν₁ + ν₂ (3307.6 cm⁻¹), ν₂ + ν₃ (3310.5 cm⁻¹), 3ν₄ (∼3345 cm⁻¹), ν₁ + ν₄ (3426.9 cm⁻¹), and ν₃ + ν₄ (3432.9 cm⁻¹). Assignments have been determined for all the bands except 3ν₄ (a weak band in a highly congested area) for a total of 4232 transitions. The total integrated intensity for this region is 5.70 cm⁻² atm⁻¹ near 296 K, and assigned lines account for 79% of the observed absorption. The two strongest bands in the region are ν₁ + ν₄ and ν₃ + ν₄ with band strengths at 296 K of 1.61 and 2.01 cm⁻² atm⁻¹, respectively. An empirical database of PH₃ line parameters (positions, intensities, and assignments) is now available. Lower state energies (corresponding to assignments from this study) and line widths from the literature are included; default values are used for unassigned features.     

有线电视基站相线和零线的检测与自动矫正

探讨了交流电网中相线和零线的正确接法以及相线和零线接反后所造成的危害，并给出了相线和零线接反时的两种自动矫正电路。     

超短波通信链路分析

主要从通信系统设计的角度出发,对超短波通信链路分析进行了初步探索,介绍了能量传播分析法和链路余量分析法以及多径条件下的考虑。结合工程实践,给出了超短波通信链路分析示例,这将有助于系统工程师预知系统设计性能、控制技术风险、进一步提高信道估值的可信度。     

微带压控振荡器设计与仿真

介绍了S波段微带压控振荡器的设计方法,并使用微波仿真软件Serenade8.5对振荡器进行仿真分析,给出了仿真和实际电路的结果。     

遗传算法在优化设计宽频微带天线中的应用

将遗传算法与FDTD法结合优化设计出了一种宽频微带天线.文中简要讨论了遗传算法的操作过程,并介绍了减少遗传算法与FDTD法结合优化微带天线计算量的方法.与初始矩形微带天线相比,优化后天线的阻抗带宽增加了三倍多.     

线有向图的幂敛指数

设G是有向图，LG表示c的线有向图，本文得到了它们的幂敛指数及周期之间的关系：k（G）－1≤（LG）≤k（G）＋1,p（LG）=p（G）特别地，当G为本原图时有：k（LG）＝k（G）＋1