基于非色散紫外算法的一氧化氮气体检测与分析

提出了一种基于非色散紫外(NDUV)算法,利用光电二极管阵列(PDA)探测器和光谱仪检测一氧化氮气体的分析方法。通过对比分析不同积分次数下一氧化氮吸收谱和无吸收谱内不同波长宽度的总光强,引入光源影响因子F和吸收谱因子B,得到吸光度与浓度的拟合方程及相关系数。结果表明,采用合适的拟合阶数、拟合波长宽度和分析方法,吸光度与浓度的二阶拟合相关系数可达0.999 9以上, 通过拟合方程所获得的待测气体浓度与标准值浓度的误差在3%以内。     

对23P2介子九重态中同位旋标量成员的质量分析

基于实验上已经确认的基态张量介子九重态的安排和现有的实验数据,利用从雷吉轨迹理论和质量混合矩阵推导出的介子质量关系,对张量介子第一径向激发态的安排做了分析预测.根据得到的结果,可以推测f₂（1810）和f₂（2010）可能作为张量介子第一径向激发态的候选者.同时给出了f₂（1810）和f₂（2010）作为张量介子第一径向激发态时的衰变信息.这些结论对激发态张量介子,特别是其中的同位旋标量态的安排将提供帮助.     

Beatings in the Spin Echo Signal in Media Having a Doublet Structure of the Spectrum

We have obtained an analytical expression for the twopulse echo signal arising in nonresonant excitation of a condensed medium with a nonuniformly broadened spectrum of doublet structure by two pulses of an electromagnetic field of different durations and of the same amplitude. It is shown that in the case where the differences between the carrying frequency of exciting pulses and the central frequencies of the spectral lines differ considerably, beatings are formed in the signal of the twopulse echo. The rate of decay of the amplitude of these beatings is found to depend only on the time of reversible and irreversible relaxation, and their circular frequency is determined by the shift of the spectral lines relative to each other. A technique for separate determination of the inhomogeneous width of the lines and time of the irreversible transverse relaxation is suggested which is based on the analysis of the twopulse echo signal beatings.     

Absorption properties of a driven Doppler—broadened ladder system with hyperfine structure

We have studied the absorption spectrum of a Doppler-broadened ladder system,where the highest level is coupled into two middle hyperfine sublevels by a strong coherent field.We find that,when the system is considered as homogeneous,either two or three spectral components are observed,depending on the detuning of the coherent field.but when the velocity distribution of atoms is considered,we can always observe one electromagnetically induced transparency (EIT) window with high dispersion.So the atomic hyperfine structure cannot be an impediment for obtaining EIT.     

Induced electric fields and plasmonic interactions between a metallic nanotube and a thin metallic film

We have numerically simulated the induced electric fields and the plasmonic interactions of a metallic nanotube near a thin metallic film. Our study shows that the energies and intensities of the plasmon resonances depend strongly on the aspect ratio (the ratio of the inner to outer radius) of the nanotube as well as the separation between the center of the nanotube and the upper surface of the metallic film and the thickness of the film. The enhancement of the induced electric field of this system reaches ...     

a-C:N:H纳米尖端荧光产生的机理

用CH4,H2和NH3为反应气体,利用等离子体增强热丝化学气相沉积在沉积有碳膜的Si衬底上制备了a-C:N:H纳米尖端,并用扫描电子显微镜和微区Raman光谱仪对碳膜和纳米尖端进行了表征。结果表明:Raman谱中含有与碳和氮相关的峰,且纳米尖端的Raman谱比碳膜的Raman谱有很强的荧光背景。Raman谱中的峰说明沉积的碳膜和纳米尖端是a-C:N:H薄膜和a-C:N:H尖端。a-C:N:H纳米尖端的Raman谱中强荧光背景的产生表明其在激发光源照射的过程中发射了强荧光,对a-C:N:H纳米尖端产生强荧光的机理进行了探讨。     

拉曼光谱法研究纳米结构多孔ZnO微球的合成机理

利用拉曼光谱方法,对柠檬酸钠辅助水热合成纳米结构多孔ZnO微球的机理进行了研究。样品的拉曼光谱特征显示,多孔ZnO微球中存在Zn-柠檬酸配合物;分析表明反应溶液中柠檬酸钠水解产生的柠檬酸根与Zn2+结合形成Zn-柠檬酸配合物,该配合物化学吸附在Zn(OH)₂晶核的(204)和(503)晶面,使Zn(OH)₂晶核择优生长形成纳米薄片状结构;水热过程中Zn(OH)₂微晶团聚形成纳米片状结构多孔Zn(OH)₂微球并以沉淀析出。研究发现吸附在薄片表面的Zn-柠檬酸配合物提高了Zn(OH)₂微晶的热稳定性,使得Zn(OH)₂的分解温度高于200 ℃,加热到300 ℃后Zn(OH)₂完全分解获得纳米结构多孔ZnO微球。     

Microwave Doppler spectra of sea return at small incidence angles: specular point scattering contribution

It is well known that the sea return echo contains contributions from at least two scattering mechanisms. In addition to the resonant Bragg scattering, the specular point scattering plays an important role as the incidence angle becomes smaller (≤20o). Here, in combination with the Kirchhoff integral equation of scattering field and the stationary phase approximation, analytical expressions for Doppler shift and spectral bandwidth of specular point scattering, which are insensitive to the polarization state, are derived theoretically. For comparison, the simulated results related to the two-scale method (TSM) and the method of moment (MOM) are also presented. It is found that the Doppler shift and the spectral bandwidth given by TSM are insufficient at small incidence angles. However, a comparison between the analytical results and the numerical simulations by MOM in the backscatter configuration shows that our proposed formulas are valid for the specular point scattering case. In this work, the dependences of the predicted results on incidence angle, radar frequency, and wind speed are also discussed. The obtained conclusions seem promising for a better understanding of the Doppler spectra of the specular point scattering fields from time-varying sea surfaces.     

Optical and mechanical properties of AlF3 films produced by pulse magnetron sputtering of Al targets with CF4/O2 gas

In this study, AlF₃ thin films were deposited by pulse magnetron sputtering of Al targets with different ratios of CF₄/O₂ gas and at different sputtering powers. The optical and mechanical properties of the AlF₃ thin films were analyzed. The transmittance spectra showed no obvious negative inhomogeneous refractive indices. Denser films with a low optical absorption were obtained when high sputtering powers were used (larger than 30 W). The lowest extinction coefficient (7.3 × 10⁻⁴ at 193 nm) of the films can be reached with 12 sccm O₂ flow rate and at 160W sputtering power. All of the residual stresses were compressive and their trends were consistent with the refractive indices. The lowest compressive stress (0.068 GPa) was obtained when the AlF₃ films were prepared at 160W sputtering power.     

紫外增强薄膜发射光谱测量中的倍波现象分析

紫外探测技术足继激光和红外探测技术之后发展起来的又一军民两用光电探测技术,在普通探测器件光敏面镀上将紫外波段的光转化为可见波段的光的变频薄膜是增强光电探测器紫外响应的主要技术.文章用"旋涂法"制备成像器件紫外增强薄膜.在对紫外增强薄膜的量子转化效率进行测量分析的实验过程中用SP1702紫外可见光栅光谱仪对薄膜的紫外变频效率进行分析,在激发光源为260和280nm时变频薄膜的发射光谱在520和560 nm附近有较明显的波峰.结合光栅光谱仪的工作原理,对该现象进行了理论分析,得出520和560 nm附近的波峰并非变频薄膜受激发发出的光波,而是光谱测量中产生的倍波现象.从分离重级光谱的角度没计了光谱分级器,以消除光谱测鼍中倍波现象的影响.