DOAS Zenith Sky Observations: 2. Seasonal Variation of BrO Over Bremen (53°N) 1994-1995     

A. Richter  M. Eisinger  A. Ladstätter-weißenmayer  J.P. Burrows 《Journal of Atmospheric Chemistry》1999,32(1):83-99

Zenith sky observations of BrO over Bremen (53°N) are reported for the period of September 1994 to January 1996. BrO differential slant columns between 90° and 80° solar zenith angle showed a strong seasonal variation between a winter maximum of 1.9·1014 molec/cm2 and a summer minimum of 0.6·1014 molec/cm2. The seasonal variation in BrO twilight values is shown to be inversely correlated with NO2 columns in agreement with current knowledge of gas phase chemistry of bromine. In contrast to model predictions, no significant difference between morning and evening BrO measurements was observed. During a 6 day polar vortex excursion to mid-latitudes OClO could be measured above Bremen indicating chlorine activation in the vortex air. No significant increase in BrO differential slant columns was detected during this time.  相似文献   

Slant Column Measurements of O3 and NO2 During the NDSC Intercomparison of Zenith-Sky UV-Visible Spectrometers in June 1996     

H. K. Roscoe  P. V. Johnston  M. Van Roozendael  A. Richter  A. Sarkissian  J. Roscoe  K. E. Preston  J-C. Lambert  C. Hermans  W. DeCuyper  S. Dzienus  T. Winterrath  J. Burrows  F. Goutail  J-P. Pommereau  E. D'Almeida  J. Hottier  C. Coureul  R. Didier  I. Pundt  L. M. Bartlett  C. T. McElroy  J. E. Kerr  A. Elokhov  G. Giovanelli  F. Ravegnani  M. Premuda  I. Kostadinov  F. Erle  T. Wagner  K. Pfeilsticker  M. Kenntner  L. C. Marquard  M. Gil  O. Puentedura  M. Yela  D. W. Arlander  B. A. Kastad Hoiskar  C. W. Tellefsen  K. Karlsen Tornkvist  B. Heese  R. L. Jones  S. R. Aliwell  R. A. Freshwater 《Journal of Atmospheric Chemistry》1999,32(2):281-314

In June 1996, 16 UV-visible sensors from 11 institutes measured spectra of the zenith sky for more than 10 days. Spectra were analysed in real-time to determine slant column amounts of O3 and NO2. Spectra of Hg lamps and lasers were measured, and the amount of NO2 in a cell was determined by each spectrometer. Some spectra were re-analysed after obvious errors were found. Slant columns were compared in two ways: by examining regression analyses against comparison instruments over the whole range of solar zenith angles; and by taking fractional differences from a comparison instrument at solar zenith angles between 85° and 91°. Regression identified which pairs of instruments were most consistent, and so which could be used as universal comparison instruments. For O3, regression slopes for the whole campaign agreed within 5% for most instruments despite the use of different cross-sections and wavelength intervals, whereas similar agreement was only achieved for NO2 when the same cross-sections and wavelength intervals were used and only one half-day's data was analysed. Mean fractional differences in NO2 from a comparison instrument fall within ±7% (1-sigma) for most instruments, with standard deviations of the mean differences averaging 4.5%. Mean differences in O3 fall within ±2.5% (1- sigma) for most instruments, with standard deviations of the mean differences averaging 2%. Measurements of NO2 in the cell had similar agreement to measurements of NO2 in the atmosphere, but for some instruments measurements with cell and atmosphere relative to a comparison instrument disagreed by more than the error bars.  相似文献   

不同颜色翡翠的微量元素及红外光谱特征   总被引：5，自引：0，他引：5       下载免费PDF全文

谢意红  王成云 《岩矿测试》2003,22(3):183-187

不同颜色翡翠的能谱分析结果及紫外可见光谱特征表明；白色翡翠含有Fe,但Fe^3 不能使翡翠产生颜色；Mn可能是紫色翡翠的致色元素；蓝色翡翠较紫色翡翠含有S及较多的Ca、Fe、Mg和较少的Mn，Fe、Mg可使紫色翡翠带蓝色色调；灰绿色翡翠较绿色翡翠有较多的Ca、Fe、Mg和极少的Cr。同时，分析对比了不同颜色A货翡翠和优化处理翡翠的红外光谱特征。  相似文献   

电子探针微区紫外阴极荧光分析系统及在沉积碎屑岩分析中的应用   总被引：3，自引：1，他引：3  

冻能松  杨勇 《地球科学》2003,28(3):357-360

在JCXA—733电子探针上采用一种实用的微区紫外一可见阴极荧光的探测方案，可以分析样品表面微区的不可见和可见的荧光．荧光的波长和强度特性与物质的成分、结构、缺陷，物质的形成条件、经历、所处环境条件等密切相关．相对于常规的可见阴极荧光测试技术，探测紫外和红外阴极荧光可以在更宽的波段上获取更多更新的样品内在信息．用此方法对河北唐山石英砂岩及其微小次生加大边进行阴极荧光分析，发现它们具有不同的紫外荧光特征，还有对应波长为287nm的辐射损伤色心，由此可以推测至少有两期胶结作用，且石英碎屑来源复杂．这为分析胶结作用期次和碎屑物物源提供了新的技术方法，对于沉积盆地分析和油气储集具有重要的实用意义．  相似文献   

Calculation of cloud modification factors for the horizontal plane eye damaging ultraviolet radiation     

A.V. Parisi  D.J. Turnbull  J. Turner 《Atmospheric Research》2007,86(3-4):278-285

This research examines the influence of cloud on the cataract effective UV (UV_Cat) irradiances on a horizontal plane over an extended period of 12months that included the range of cloud conditions, solar zenith angle (SZA) and ozone conditions experienced over that time. The data were collected at five minute intervals. Cloud modification factors were determined from the influence of clouds on the global broadband solar radiation and these were applied to the cloud free cataract effective UV to evaluate the UV_Cat irradiances on a horizontal plane for all cloud conditions. A comparison of the measured and calculated UV_Cat irradiances for the 2004 data set in the range of SZA of 70° or less provided an R² value of 0.85. The data in the first 6months of 2005 for an SZA of 70° or less that were at a different time to that when the technique was developed provided an R² value of 0.83 for the comparison of the measured and calculated UV_Cat irradiances.  相似文献   

Degradation of Reactive Brilliant Red X‐3B Dye by Microwave Electrodeless UV Irradiation     

Ying‐Jie Cai  Li‐Na Lin  Dong‐Sheng Xia  Qing‐Fu Zeng  Hai‐Liang Zhu 《洁净——土壤、空气、水》2011,39(1):68-73

Degradations of reactive brilliant red X‐3B solution by both conventional UV irradiation and microwave electrodeless UV irradiation were investigated. Degradation processes were studied by UV–VIS spectrophotometry, total organic carbon (TOC), high performance capillary electrophoresis (HPCE), conductivity, pH value, and ion chromatography. The results of color removal (%) and TOC removal (%) showed that the degradation by microwave electrodeless UV irradiation was more effective than by conventional UV irradiation. The results of UV–VIS absorption spectra and HPCE analyses indicated that the degradation of reactive brilliant red X‐3B was occurred at the conjugation system first, the benzene ring and the naphthalene ring later. The reactive brilliant red X‐3B was cleaved into some new small compounds and eventually most of the organic substances were mineralized to CO₂ and H₂O. The results of the conductivity analysis suggested that the degradation has mainly occurred in the first 40 min of reaction. The pH value of reactive brilliant red X‐3B solution was decreased first and then was increased. The results of inorganic anions analysis hinted that many of the N, Cl, and S elements from reactive brilliant red X‐3B were still attached in organic molecules.  相似文献   

All you ever wanted to know about optical long baseline stellar interferometry, but were too shy to ask your adviser     

Florentin Millour   《New Astronomy Reviews》2008,52(2-5):177

I try to present a small view of the properties and issues related to astronomical interferometry observations. I recall a bit of history of the technique, give some basic assessments to the principle of interferometry, and finally, describe physical processes and limitations that affect optical long baseline interferometry and which are, in general, very useful for everyday work. Therefore, this text is not intended to perform strong demonstrations and show accurate results, but rather to transmit the general “feeling” one needs to have to not be destabilised by the first contact to real world interferometry.  相似文献   

时间分辨紫外脉冲荧光法测定锆矿中的铀     

范增伟  丁楠  谢胜凯  王铁健  李伯平 《铀矿地质》2019,(2):95-100

基于前人研究工作,开展时间分辨紫外脉冲荧光法测定天然伴生放射性锆矿样品中铀含量的方法研究。与电感耦合等离子体质谱法相比,该法正确度好、精密度高、抗干扰能力强、适应性强。实验表明体系酸碱度影响荧光强度显著,但当pH值在6.85～9.10范围时,荧光强度较高且相对稳定。对31种阳离子干扰进行实验,结果表明Sn、Cr、Sb、Tl、Rh、Mn、Ag、Bi等阳离子可使荧光强度显著降低;溶液中Zr元素质量浓度低于200μg·mL^-1时,对荧光强度影响不明显,Zr元素质量浓度为200～500μg·mL^-1时,荧光强度随Zr元素质量浓度的增加而逐渐减弱。采用过氧化钠碱熔-硝酸提取天然伴生放射性锆矿样品,样品能够消解完全。采用标准加入法,用紫外脉冲荧光法测定铀含量,检出限为0.05μg·g^-1,测定范围为0.15～4500μg·g^-1;铀含量在40～735μg·g^-1时,RSD为2.1%～7.7%;铀含量为288μg·g^-1的锆矿样品,正确度为5.2%。  相似文献   

The Degradation of Natural Organic Matter in Surface Water by a Nano‐TiO2/Diatomite Photocatalytic Reactor          下载免费PDF全文

Wen Sun  Huaqiang Chu  Dawen Cao  Shuilin Zheng 《洁净——土壤、空气、水》2014,42(9):1190-1198

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Temporal and spatial variability of EUV flux at 094 Å and its relationship with sunspot activity     

《New Astronomy》2024

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