Statistical study of EUV and X-ray transient brightenings     

Jing-Wei Li  Hui Li 《中国天文和天体物理学报》2010,10(7)

Using the visual inspection and base difference method and data from the X-ray Telescope(XRT)onboard Hinode and TRACE with improved spatial and temporal resolution,we selected 48 X-ray transient brightenings(XTBs)and 237 EUV transient brightenings(ETBs)to study the connection between these two types of transient brightenings(TBs).These ETBs and XTBs have smaller areas(8.42 Mm2 and 36.3 Mm2,respectively,on average)and shorter durations(9.0 rain and 6.9 min,respectively,on average)than previous studies.These XTBs show three types of morphological structure: point-like,single-loop and multiple-loop.We find only 20% of the ETBs have corresponding XTBs while the other 80% have no X-ray signatures at all.This is presumably due to the small amount of released energy,which is not enough to heat the plasma to coronal temperatures which produce X-ray emission rather than being due to the limitation of spatial resolution and temperature sensitivity of the X-ray instrument.These small ETBs may significantly contribute to the coronal heating.  相似文献   

用原子吸收仪进行钛的紫外分光光度测定   总被引：1，自引：0，他引：1  

杨重九 《岩矿测试》2001,20(3):234-236

在原子吸收仪上添置了一个自制的简易比色皿托架，成功地利用原子吸收仪进行TiO2与二安替比林甲烷显色的分光光度测定。  相似文献   

On the use of UV spectrophotometry to assess dissolved organic carbon origin variations in the Upper Rhône River     

J. C. Rostan  B. Cellot 《Aquatic Sciences - Research Across Boundaries》1995,57(1):70-80

To detect temporal changes and the origin of the refractory dissolved organic matter in the Upper Rhône River, UV light absorbance (A) at 285 nm and quantitative dissolved organic carbon (DOC) measurements were carried out. Data from 63 visits to the main channel over a period of two years and from visits to different waterbodies in the alluvial plain before and after a flood are presented. There was a good correlation between A (0.019–0.160) and the DOC content (1.40–9.81 mg/L) for the waterbodies, but not for the river axis with lower A (0.013–0.044) and DOC content (1.13–2.20 mg/L). Due to this good correlation, the DOC content could be quantified for the waterbodies by absorbance measurements only. For the river water this indirect determination of the DOC content was not possible. However, the A/DOC ratio showed changes in the composition of DOC of river water and provided indications about the origin of the dissolved organic matter in the Upper Rhône River.  相似文献   

非常规气象要素在紫外线预报中的应用     

谢静芳  应爽  刘海峰  陈雷 《气象科技》2020,48(2):248-253

利用吉林省业务运行的WRF模式,计算了与紫外线指数相关的气温、湿度、云量、风速等常规气象要素和地表向下的短波辐射通量、地面热通量、反照率等非常规气象要素,利用长春市紫外线观测资料,分析了紫外线辐射与常规和非常规气象要素的相关性。基于长春市紫外线观测实况,以常规气象要素、非常规气象要素、混合气象要素为因子,利用相同的统计建模方法,分别建立紫外线预报模型。结果表明:大气短波辐射等非常规气象要素与紫外线指数的相关性,明显高于气温、云量、比湿、风速等常规气象要素;应用非常规气象要素和混合气象要素的紫外线预报方程,显著优于常规气象要素;基于混合气象要素的紫外线预报方程,与基于非常规气象要素的预报方程比较,预报性能差异不大。此外,应用常规气象要素建立的分季节紫外线预报方程,其预报效果明显优于全年预报方程。应用非常规气象要素建立的分季节紫外线预报方程,与全年预报方程相比,预报效果差异不大。  相似文献   

广州地区太阳分光辐射的某些变化特征   总被引：1，自引：0，他引：1       下载免费PDF全文

熊效振  王新宇  王庚辰  张绍坤  于汇滨  刘旭 《应用气象学报》1994,5(1):98-103

利用广州地区1985—1990年的太阳分光辐射的连续观测资料（观测角度为23°11′），研究了广州地区紫外辐射、可见光辐射（光合有效辐射）、近红外辐射的某些特征。结果指出，每年7—10月份各分光辐射及总辐射总量较大。月总辐射中可见光辐射占总辐射的百分比年平均为47.3%，相应的紫外辐射和近红外辐射分别占7.1%和45.6%。文中还分析了晴天条件下分光辐射的变化和1990年紫外辐射变化的某些特征，并分析和讨论了分光辐射与云量、日照时间等因子的相关。  相似文献   

Solar-Blind Diamond Detectors for Lyra, the Solar VUV Radiometer on Board Proba II     

A. Benmoussa  J.-F. Hochedez  W. K. Schmutz  U. SchÜhle  M. NeslÁdek  Y. Stockman  U. Kroth  M. Richter  A. Theissen  Z. Remes  K. Haenen  V. Mortet  S. Koller  J. P. Halain  R. Petersen  M. Dominique  M. D’Olieslaeger 《Experimental Astronomy》2003,16(3):141-148

Fabrication, packaging and experimental results on the calibration of metal-semiconductor-metal (MSM) photodetectors made on diamond are reported. LYRA (Lyman- RAdiometer onboard PROBA-2) will use diamond detectors for the first time in space for a solar physics instrument. A set of measurement campaigns was designed to obtain the XUV-to-VIS responsivity of the devices and other characterizations. The measurements of responsivity in EUV and VUV spectral ranges (40–240 nm) have been carried out by the Physkalisch-Technische Bundesanstalt (PTB) in Germany at the electron storage ring BESSY II. The longer wavelength range from 210 to 1127 nm was measured with monochromatic light by using a Xe-lamp at IMO-IMOMEC. The diamond detectors exhibit a photoresponse which lie in the 35–65 mA/W range at 200 nm (corresponding to an external quantum efficiency of 20–40%) and indicate a visible rejection ratio (200–500 nm) higher than four orders of magnitude.  相似文献   

昆明下半年紫外辐射变化及与云的关系分析     

郭世昌  常有礼  李豪杰 《云南地理环境研究》2005,17(1):1-4,23

依据2003年8月1日到2003年12月31日同步观测得到的地面紫外辐射资料,分析了紫外辐射的变化特征。结果显示,在实际天气条件下,紫外辐射变化没有我们所认为的那种有特别明显的规律。云对到达地面的紫外辐射可能有着十分复杂和重要的作用。  相似文献   

Induction of thymine dimers by solar radiation in natural freshwater phytoplankton assemblages in Patagonia, Argentina     

Manfred Klisch  Rajeshwar P. Sinha  E. Walter Helbling  Donat-P. Häder 《Aquatic Sciences - Research Across Boundaries》2005,67(1):72-78

  相似文献   

紫外线试验数据采集与控制系统研究     

万长建  郑有飞 《南京气象学院学报》1998,21(4):691-695

采用８０３１、８２７９、８２５５、ＡＤＣ０８０９、２７６４、６２６４等芯片及温敏电阻、紫外辐射和总辐射探头等传感器组成一实用的紫外线试验计算机数据采集与控制。系统可定时采集温度等气象要素,定时打开与关闭辅助紫外灯,并可通过打印机输出观测结果。  相似文献   

Field Measurements of Atmospheric Photolysis Frequencies for O3, NO2, HCHO, CH3CHO, H2O2, and HONO by UV Spectroradiometry     

A. Kraus  A. Hofzumahaus 《Journal of Atmospheric Chemistry》1998,31(1-2):161-180

A calibrated spectroradiometer was used for the measurement of spectra of the absolute actinic flux F during the POPCORN field campaign in Pennewitt (53.8° N, 11.7° E, sea level) in August 1994. The obtained set of actinic flux spectra was used to determine the photolysis frequencies J(O1D), J(NO2), J(HCHO), J(H2O2), J(HONO), and J(CH3CHO), using molecular photodissociation data from literature. The accuracy of the actinic flux measurement was about ±5%. The accuracy of the photolysis frequency determination is limited by the uncertainties of the molecular absorption cross section and quantum yield data. A good agreement within the experimental uncertainties was found in comparison with measurements of J(O1D) and J(NO2) by filterradiometer which were calibrated absolutely against chemical actinometer. A comparison of this work's photolysis frequency measurements at 40° solar zenith angle with respective measured and modeled data from the literature also shows good agreement for most of the processes considered in this work. However, in the case of J(NO2) data reported in the literature as a function of solar zenith angle differences up to a factor of 1.6 with respect to this work's J(NO2) data are observed. Since this is far beyond the estimated experimental uncertainties, other atmospheric variables, such as aerosols, seem to affect J(NO2) to an extent that is underestimated by now and make indirect comparisons of J(NO2) measurements difficult.  相似文献