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.     

红外探测装置中光谱分光镜的设计与制备

在红外探测装置中,光谱分光镜是用来把3 μm～5 μm和8 μm～12 μm 2个波段的光谱分开的零件.介绍了一种在通用镀膜机上制备光谱分光镜的新工艺.在该膜系的设计过程中,把Willey公式引入到对其平均透过率最高值进行估算的过程中,同时针对国产镀膜机控制精度不高的特点,尽量使用规整膜层进行设计.为了进一步提高8 μm～12 μm波段的透过率,在膜系的最外侧引进了一层自行配制的低折射率氟化物材料,制备出了符合技术指标的红外光谱分光镜.     

利用近红外光谱检测多层组织血氧饱和度的研究

利用近红外光谱无创检测生物组织血氧饱和状态,是一种极富研究和应用前景的检测技术,在临床检测中被广泛应用.但常规临床检测应用于指端仅反映局部血氧饱和度信息,在使用中具有局限性,信号的可信度也存在质疑.该文提出了一种采用反射式脉搏血氧饱和度检测技术检测生物多层组织氧合状况的新方法,该方法通过调节入射光强以适应解剖学中生物组织多层结构的检测.应用该方法针对手指结构的实验结果表明,随着入射光强的改变,反映血氧饱和状态的光电脉搏波信号有显著变化.结合手指解剖学分析表明,光电脉搏波信号的变化与手指的多层面组织结构相对应,反映不同层面血氧饱和状态.这一特点表明,通过此法可以针对生物组织的多层结构进行测量.     

O2分子激发态a1Δg和b1Σ+g态的分析势能函数

以aug-cc-pVQZ,cc-pV5Z,6-311++g（d,p）和6-311++g（3df,3pd）等为基函数,采用多组态相互作用（MRCI）方法对O₂分子最低的两个激发态¹Δ_g和¹Σ⁺_g的平衡结构、谐振频率和势能曲线进行了计算.并选用Murrell-Sorbie势能函数对曲线进行拟合,利用拟合的参数值计算出了力常数和光谱数据.结果表明计算值与实验值符合较好. 关键词： MRCI 势能函数 力常数 光谱数据     

Spectral characterization of diffusion with chemical shift resolution: Highly concentrated water-in-oil emulsion

We present a modulated gradient spin-echo method, which uses a train of sinusoidally shaped gradient pulses separated by 180° radio-frequency (RF) pulses. The RF pulses efficiently refocus chemical shifts and de-phasing due to susceptibility differences, resulting in undistorted, high-resolution diffusion weighted spectra. This allows for the simultaneous spectral characterization of the diffusion of several molecular species with different chemical shifts. The technique is robust against susceptibility artifacts, field inhomogeneity and imperfections in the gradient generating equipment. The feasibility of the technique is demonstrated by measuring the diffusion of water, oil, and water-soluble salt in a highly concentrated water-in-oil emulsion. The diffusion of water and salt reveal precise information about the droplet size distribution below the μm-range. Common droplet size distribution explains both the data for water with finite long-range diffusion and the data for salt with negligible long-range diffusion. The results of water diffusion show that the technique is efficient in deconvolving the effects of molecular exchange between droplets and restricted diffusion within droplets. The effects of water exchange suggest that droplets of different sizes are uniformly distributed within the sample.     

以香草素为内标之气相层析光谱法定量牛樟木精油指标成分松油醇的快速分析方法

牛樟精油具有独特浓郁的香气,其中以α-松油醇(α-terpineol)为牛樟精油主要成分。由于樟树精油制品可依种类、变种、亚种等不同而有不同成分,以松油醇最具独特性,可作为牛樟木精油品质重要指标成分,应用以区别牛樟树与冇樟以及香樟等木材精油的方法,因此建立市售牛樟木精油指标成分α-松油醇含量的简便快速又准确的检验方法便有其必要性。该研究拟以市售精油液体样品,不经任何前处理,加入适当之内标准溶液溶解后,直接注入气相层析光谱仪中,配合适当的分离管柱及气相层析条件,以期建立简便快速又准确的牛樟木精油指标成分α-松油醇之定量方法。毛细管柱气相层析具有高解析度及高灵敏度等优点,仍为现代最重要分析技术之一,因此研究建立了以香草素为内标准定量牛樟木精油指标成分α-松油醇(α-terpineol)之气相色谱层析法的快速分析方法。牛樟木精油液体样品,加入适当量之香草素内标准溶液混合溶解后,即可直接注入配有广口径之毛细管柱(megabore column)气相色谱仪中分析,相当简便,每分析一个样品仅需约30 min。结果显示松油醇之最低定量浓度（limit of quantitation, LOQ）为1 μg·mL-1左右。在添加回收试验中添加松油醇1.0及10.0 mg 于市售冇樟精油及牛樟精油中,其回收率在98%~103%,变异系数均在10.8%以下,显示该方法的精密度相当高。以该研究建立的方法分析15件市售牛樟精油中松油醇含量,结果显示,市售牛樟木精油的松油醇含量最高约51.6%及最低为21.3%左右,此结果显示以定量松油醇作为市售牛樟精油品质指标是一快速、准确且可行的方法。