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121.
Curtis P. Rinsland Linda Chiou Chris Boone Peter Bernath Emmanuel Mahieu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(18):2127-2134
The first measurement of the HCFC-142b (CH3CClF2) trend near the tropopause has been derived from volume mixing ratio (VMR) measurements at northern and southern hemisphere mid-latitudes for the 2004–2008 time period from spaceborne solar occultation observations recorded at 0.02 cm−1 resolution with the ACE (atmospheric chemistry experiment) Fourier transform spectrometer. The HCFC-142b molecule is currently the third most abundant HCFC (hydrochlorofluorocarbon) in the atmosphere and ACE measurements over this time span show a continuous rise in its volume mixing ratio. Monthly average measurements at northern and southern hemisphere mid-latitudes have similar increase rates that are consistent with surface trend measurements for a similar time span. A mean northern hemisphere profile for the time span shows a near constant VMR at 8–20 km altitude range, consistent on average for the same time span with in situ results. The nearly constant vertical VMR profile also agrees with model predictions of a long lifetime in the lower atmosphere. 相似文献
122.
Zakir Murtaza Leah Tolosa Peter Harms Joseph R. Lakowicz 《Journal of fluorescence》2002,12(2):187-192
We describe a new approach to optical sensing of glucose based on the competitive interactions between a ruthenium metal ligand complex, a boronic acid derivative and glucose. The metal-ligand complex [Ru(2,2-bipyridine)2(5,6-dihydroxy-1,10-phenanthroline)](PF6)2 at pH 8 forms a reversible complex with 2-toluylboronic acid or 2-methoxyphenyl boronic acid. Complexation is accompanied by a several-fold increase in the luminescent intensity of the ruthenium complex. Addition of glucose results in decreased luminescent intensity, which appears to be the result of decreased binding between the metal-ligand complex and the boronic acid. Ruthenium metal-ligand complexes are convenient for optical sensing because their long luminescent decay times allow lifetime-based sensing with simple instrumentation. 相似文献
123.
Squaraines are a group of fluorescent dyes and pigments derived from squaric acid and dialkylanilines well known in applications such as photoreceptors, organic solar cells, optical recording media, and non-linear optics. Their very promising spectral properties, long wavelength absorption and emission, and high absorptivity and quantum yields have not been exploited so far in relation to optical sensor design. They exhibit excellent solubility in sol-gel matrices, and the ligand is an integral part of the fluorophore system, which makes the molecule a fluoroionophore. In this work, potassium-sensing agent, bis[4-N-(1-aza-4,7,10,13,16-pentaox acyclooctadecyl)-3,5-dihydroxyphenyl] squaraine has been used for potassium sensing in a sol-gel matrix. The spectrofluorimetric response of dye-doped tetraethyl ortosilicate (TEOS) film after exposure to certain concentrations of K+ has been investigated, and 62% of relative signal change was achieved. The dynamic working range of the sensor membrane has been found between 10–9 and 10–6 M K+, in other terms from nanomolar to micromolar levels, which is an advantage over flame emission spectroscopy, in view of detection limit. The sensor is fully reversible within the dynamic range and the response time (90) is found to be 2 min under batch conditions. The cross-sensitivity of the molecule to Na+, Ba2+, Ca2+, and NH+
4 was also tested in separate solutions. 相似文献
124.
以二乙氨基乙基交联葡聚糖凝胶为基质的铝荧光传感层 总被引:1,自引:0,他引:1
本文基于Al^3+离子对电价键固定在二乙氨基乙基交联葡聚糖凝胶上的水杨基荧光 酮的可逆荧光淬灭作用,研制了测定Al^3+离子浓度的荧光传感层。 相似文献
125.
We have explored the opportunities for enhanced ratiometric pH sensing using the well-known carboxy seminaphthofluorescein (SNAFL-2) and silver island films (SiFs). Our results show that the metallic surfaces can provide up to a 40-fold increase in probe fluorescence intensity as compared to nonmetallic surfaces with the same probe coverage. However, while the S/N is significantly better for pH sensing, the emission wavelength ratiometric values are similar to that obtained in solution, due to the fact that the emission of both the acidic and basic forms of the probe are enhanced to similar extents. To the best of our knowledge this is the first report of enhanced ratiometric fluorescence sensing on metallic surfaces. 相似文献
126.
Satellite observations of polar stratospheric clouds (PSCs) in the mid-infrared by high resolution limb emission spectrometers like the Michelson Interferometer for Passive Atmospheric Sounding have been simulated. For particles with radius the scattered tropospheric radiance accounts for a significant part of the continuum signal and leads to absorption line features overlaid over the stratospheric emission spectrum. The scattered radiance shows a strong dependence on particle size up to about radius with a maximum around 3-4. The contribution of scattered radiation depends heavily on tropospheric cloud coverage and earth surface temperature. Distinction of PSCs of different composition is possible for small particles due to differences in the imaginary part of the refractive index. For particles with radii between 1 and the simulated spectra for various PSC compositions differ due to different real parts of the refractive index. For larger particles no distinction is possible any more. Solar radiance scattered by PSCs is important for wavenumbers larger than about . For a forward scattering geometry with 30° between the position of the sun and the limb viewing direction solar contribution exceeds the terrestrial scattered radiation by about a factor of 10. 相似文献
127.
128.
星载太阳紫外光谱监视器的地面辐射定标 总被引:1,自引:2,他引:1
星载太阳紫外光谱监视器是一种小型化、高精度紫外-真空紫外光谱辐射计,它有两种工作模式,即探测太阳紫外光谱辐照度的太阳模式和探测大气的太阳后向散射紫外光谱辐亮度的大气模式。对应这两种工作模式分别建立了紫外-真空紫外光谱辐照度和紫外光谱辐亮度定标装置。光谱辐照度标准灯直接辐照仪器的漫反射板进行仪器的光谱辐照度响应度定标,光谱辐照度标准灯辐照标准漫反射板形成朗伯面光源进行仪器的光谱辐亮度响应度定标。误差分析表明:160~250 nm光谱辐照度绝对定标误差为6.5%,250~400 nm为4.3%;250~400 nm光谱辐亮度绝对定标误差为5.9%。星载太阳紫外光谱监视器获得的地外太阳紫外光谱辐照度与大气的太阳后向散射光谱辐亮度数据,同国际上的观测结果相比一致性达±10%。 相似文献
129.
130.
介绍了一种新型的具有双参量测量功能的光纤布喇格光栅传感器.该传感器采用了特殊的结构,安装了两个不同中心波长的光纤布喇格光栅,可以实现两曲面之间狭小间隙的微小位移和温度的同时测量.实验表明,该传感器结构紧凑、体积小,具有良好的重复性和稳定性,位移测量误差不超过±10 μm,温度测量误差不超过±2℃. 相似文献