Interference Testing for Atmospheric HOx Measurements by Laser-induced Fluorescence     

Xinrong Ren  Hartwig Harder  Monica Martinez  Ian C. Faloona  David Tan  Robert L. Lesher  Piero Di Carlo  James B. Simpas  William H. Brune 《Journal of Atmospheric Chemistry》2004,47(2):169-190

Accurate OH and HO₂ (collectively called HO_x) measurements by laser-induced fluorescence (LIF) may be contaminated by spurious signals from interfering atmospheric chemicals or from the instrument itself. Interference tests must be conducted to ensure that observed OH signal originates solely from ambient OH and is not due to instrument artifacts. Several tests were performed on the Penn State LIF HO_x instrument, both in the laboratory and in the field. Theseincluded measurements of the instrument's zero signal by using either zero air or perfluoropropylene to remove OH, examination of spectral interferences from naphthalene, sulfur dioxide, and formaldehyde, and tests of interferences by addition of suspected interfering atmospheric chemicals, including ozone, hydrogen peroxide, nitrous acid, formaldehyde, nitric acid, acetone, and organic peroxy radicals (RO₂). All tests lacked evidence ofsignificant interferences for measurements in the atmosphere, including highly polluted urban environments.  相似文献   

Photodegradation of the pharmaceuticals atorvastatin, carbamazepine, levofloxacin, and sulfamethoxazole in natural waters     

Monica W. Lam  Scott A. Mabury 《Aquatic Sciences - Research Across Boundaries》2005,67(2):177-188

  相似文献   

Landslides in Emilia-Romagna region (Italy): strategies for hazard assessment and risk management   总被引：1，自引：2，他引：1  

Giovanni Bertolini  Monica Guida  Marco Pizziolo 《Landslides》2005,2(4):302-312

In Emilia-Romagna, over 32,000 landslide bodies cover one-fifth of the hilly and mountainous territory. The majority of them originated as earth-flows after the last glacial maximum and grew during the rainiest periods of the Holocene through the superimposition of new earth-flows. Reactivation of these large landslides is the main problem the geologists of Emilia-Romagna are facing now. Intense and/or prolonged precipitation play a major role as triggering factors in reactivating landslide bodies, but also the importance of snowmelt is suggested by the monthly distribution of landslide events. Almost all the present-day landslide activity is due to the reactivation of pre-existing landslide bodies. Consequently, territorial planning and geo-thematic cartography are fundamental tools for the reduction of risk. The Emilia-Romagna geo-thematic cartography (1:10,000) is legally binding and regulates land use in regional, municipal and basin plans.  相似文献   

A surge of Skobreen, Svalbard     

Monica Sund 《Polar research》2006,25(2):115-122

Surging glaciers are common in Svalbard yet relatively few glaciers have been observed during a surge. This paper presents observations of the currently surging glacier Skobreen, in southern Spitsbergen. The study is based on examinations of new and archival photographs and maps. Skobreen, an 18 km² valley glacier terminating into the lower part of the glacier Paulabreen, has not been registered previously as a surging glacier. Skobreen experienced a build-up in its upper part, while there has been a lowering of the surface in the terminal region. Photographs from 1990 show incipient crevassing in the upper part. Photographs from 2003 show a slight advance of the terminus and marginal crevassing, indicating an initiation period of about 15 years for a surge of this glacier. In June 2005 transverse crevassing appeared in the upper part of the glacier, while the middle section moved as a block with strong shear margins and a pronounced drawdown of the ice surface. No traces of a surge front could be seen in the crevasse pattern. However, the crevasse pattern indicates an initiation area in the transition zone between the transverse crevassing in the upper part and the block of ice in the middle region.  相似文献   

Magma ascent and eruptive processes from textural and compositional features of Monte Nuovo pyroclastic products, Campi Flegrei, Italy     

Monica Piochi  Giuseppe Mastrolorenzo  Lucia Pappalardo 《Bulletin of Volcanology》2006,68(5):496-496

  相似文献   

1997年9月26日意大利中部Umbria-marche地震前的水文地质变化     

Monica Carro  Lucia Luzi  曹玲玲 《国际地震动态》2006,(7):71-85

分析了1997年9月26日意大利中部Umbria与marche交界地区的Umbria-marche地震序列引起的水文体系的变化。为了量化水文体系的变化,从地方当局和矿泉水公司收集了地下水位、泉水的流量以及河水流速等的资料,这些资料可以确定异常的影响面积,并且可以通过与从震前几年资料估算出的年平均体系的对比来量化异常的变化,试图对异常进行判定。分析结果表明,两个含水单元,即Umbria-marche山峰和Val-nerina单元,具有紧密的联系,它们都由于水文系统的改变而受到影响。地震前几个月两条河流测量站记录到了异常变化,认为是地震前兆异常。  相似文献   

On the evolution of the cosmic supernova rates     

Piero Madau  Massimo Della Valle  & Nino Panagia 《Monthly notices of the Royal Astronomical Society》1998,297(1):L17-L22

The Galactic radio-emitting X-ray binary Cygnus X-3 is known to be a source of large-scale radio jets associated with periods of intense radio flaring. These jets have been found to have an expansion velocity of ∼0.3 c and are believed (on kinematic grounds) to lie close to the plane of the sky. We present new observations of Cygnus X-3 using the VLBA at 15 GHz. These observations, which included the detection of two small flares, show an additional kind of behaviour with apparent superluminal expansion along both major and minor axes. Evidence for superluminal activity has been found in a number of X-ray binary systems such as GRS 1915+105 and GRO J1655−40 with their superluminal radio jets. Apparently similar morphologies of the Galactic and extragalactic jet sources have led to the X-ray binaries being described as 'micro-quasars'. The superluminal expansion seen in our results appears to be different in nature from these other two sources, and a number of mechanisms are presented and discussed.  相似文献   

Effect of XFe and fO2 on the FTIR and Mössbauer spectra of richterites in the system K2O-Na2O-CaO-MgO-FeO-Fe2O3-TiO2-SiO2-H2O     

J. Sergent  J. -L. Robert  B. Boukili  G. Della Ventura 《Physics and Chemistry of Minerals》1996,23(4-5):308-308

  相似文献   

Quartz deformation mechanisms in metasediments from Prins Karls Forland, Svalbard     

Daria Monica Walniuk  Alan Paul Morris 《Tectonophysics》1985,115(1-2)

  相似文献   

An alternative model for positive shifts in shallow-marine carbonate δ¹³C and δ¹⁸O     

Adrian Immenhauser  Giovanna Della Porta  Jeroen A. M. Kenter  Juan R. Bahamonde† 《Sedimentology》2003,50(5):953-959

Abstract Positive shifts in global seawater δ¹³C_DIC are related to changes in the ratio of organic relative to inorganic carbon burial in oceanic basins, whereas factors such as climatic cooling and the accumulation of polar ice are known to cause positive shifts in δ¹⁸O. Here, an alternative model is proposed for the formation of local positive isotope shifts in shallow-marine settings. The model involves geochemically altered platform-top water masses and the effects of early meteoric diagenesis on carbonate isotopic composition. Both mechanisms are active on modern (sub)tropical carbonate platforms and result in low carbonate δ¹³C and δ¹⁸O relative to typical oceanic values. During high-amplitude transgressive events, the impact of isotopically light meteoric fluids on the carbonate geochemistry is much reduced, and ¹³C-depleted platform-top water mixes with open oceanic water masses having higher isotope values. Both factors are recorded as a transient increase in carbonate ¹³C and ¹⁸O relative to low background values. These processes must be taken into consideration when interpreting the geochemical record of ancient epeiric seas.  相似文献