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1.
V Sanfelix ET Gòmez MM Jordán T Sanfeliu S Pallarés AB Vicente 《Environmental Geology》2005,47(6):811-819
The objective of this work is to assess the concentrations of three factions of air particles (settable particles, TSP and PM10) and the levels of several toxic elements in a clay atomisation industry through aerosol sampling at several points inside an industrial plant. Mechanical activities, which produce diffuse emissions, are the main process of discharge of particles in both indoor and outdoor workplace environments in the atomisation plant. The levels of As, Cd, Pb, Zn, Ba and Ni increase in the zones with higher concentrations of particles and lower ventilation. The concentrations of As and F are not influenced by the recycling processes. The levels of Cd and Pb do not show great enrichment in air particles collected inside the atomisation plant although the content of both elements is associated with ceramic muck recycling. Finally, the content of B in waste water is mainly transferred in gaseous phase to the atmosphere during the process of drying by atomisation. 相似文献
2.
土地利用/土地覆被变化遥感监测研究 总被引：3，自引：0，他引：3
根据1990年和1999年两期TM/ETM 遥感数据,运用遥感分类中的监督分类方法,全面分析乌鲁木齐市的土地利用的数量变化特征和空间变化特征,阐明了区域土地利用变化的区域特点。 相似文献
3.
V. Hambaryan D. Wagner J.G. Schmidt M. M. Hohle R. Neuhuser 《Astronomische Nachrichten》2015,336(6):545-565
We performed an X‐ray timing and spectral analysis of the variable source 3XMM J185246.6+003317 to investigate its physical nature. The data from all observations of 3XMMJ185246.6+003317 conducted by XMM‐Newton EPIC MOS1 and MOS2 with the same instrumental setup in 2004–2009 were reprocessed to form a homogenous data set of solar barycenter corrected photon arrival times and high S/N spectra of 3XMM J185246.6+003317. A Bayesian method for the search, detection, and estimation of the parameters of a periodic signal of unknown shape was employed, as developed by Gregory & Loredo (1992, 1993). The results show that 3XMM J185246.6+003317 is a transient neutron star with the genuine spin‐period of 23.11722 (23.11711–23.11727) s and its derivative of 5.3(0.3–5.5)×10–11 s s–1, implying a characteristic age of 7 (6–104) kyr, if the period derivative can be ascribed to the genuine spin‐down rate of the neutron star. The rotational‐phase averaged X‐ray spectra at the different brightness periods can be fitted with a highly absorbed blackbody model with different temperatures. The phase‐folded light curves in different energy bands with high S/N ratio show a double‐peaked profile; the variations depend on time and energy, indicating that radiation emerges from at least two emitting areas. The spectra at the phases corresponding to the maxima in the phase‐folded light curve show different spectral parameters of absorbed blackbody radiation, i.e. the hotter one has a smaller size. The source is detected only from September 2008 to April 2009 with persistently decreasing brightness, but not before, even though it was observed by XMM. Hence, it is a transient neutron star or a binary system hosting it. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
4.
T. Eisenbeiss M. Moualla M. Mugrauer T.O.B. Schmidt St. Raetz R. Neuhuser Ch. Ginski M.M. Hohle A. Koeltzsch C. Marka W. Rammo A. Reithe T. Roell M. Va&#x;ko 《Astronomische Nachrichten》2009,330(5):439-458
We have performed deep, wide‐field imaging on a ∼0.4 deg2 field in the Pleiades (Melotte 22). The selected field was not yet target of a deep search for low mass stars and brown dwarfs. Our limiting magnitudes are R ∼ 22 mag and I ∼ 20 mag, sufficient to detect brown dwarf candidates down to 40 MJ. We found 197 objects, whose location in the (I, R – I) color magnitude diagram is consistent with the age and the distance of the Pleiades. Using CTK R and I as well as JHK photometry from our data and the 2MASS survey we were able to identify 7 new brown dwarf candidates. We present our data reduction technique, which enables us to resample, calibrate, and co‐add many images by just two steps. We estimate the interstellar extinction and the spectral type from our optical and the NIR data using a two‐dimensional χ2 fitting (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
5.
M. Mugrauer M.M. Hohle C. Ginski M. Vanko F. Freistetter 《Astronomische Nachrichten》2009,330(5):425-429
We present follow‐up observations of comet 17/P Holmes after its extreme outburst in brightness, which occurred end of October 2007. We obtained 58 V‐band images of the comet between October 2007 and February 2008, using the Cassegrain‐Teleskop‐Kamera (CTK) at the University Observatory Jena. We present precise astrometry of the comet, which yields its most recent Keplerian orbital elements. Furthermore, we show that the comet's coma expands quite linearly with a velocity of about 1650 km/s between October and December 2007. The photometric monitoring of comet 17/P Holmes shows that its photometric activity level decreased by about 5.9 mag within 105 days after its outburst (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
6.
St. Raetz M. Mugrauer T.O.B. Schmidt T. Roell T. Eisenbeiss M.M. Hohle N. Tetzlaff M. Va&#x;ko A. Seifahrt Ch. Broeg J. Koppenhoefer R. Neuhuser 《Astronomische Nachrichten》2009,330(5):475-481
We report on observations of transit events of the transiting planets XO‐1b and TrES‐1 with a 25 cm telescope of the University Observatory Jena. With the transit timings for XO‐1b from all 50 available XO, SuperWASP, Transit Light Curve (TLC)‐Project‐ and Exoplanet Transit Database (ETD)‐data, including our own I ‐band photometry obtained in March 2007, we find that the orbital period is P = (3.941501 ± 0.000001) d, a slight change by ∼3 s compared to the previously published period. We present new ephemeris for this transiting planet. Furthermore, we present new R ‐band photometry of two transits of TrES‐1. With the help of all available transit times from literature this allows us to refine the estimate of the orbital period: P = (3.0300722 ± 0.0000002) d. Our observations will be useful for future investigations of timing variations caused by additional perturbing planets and/or stellar spots and/or moons (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
7.
MM Cruickshank RW TomlinsonD BondPM DevineCJW Edwards 《Applied geography (Sevenoaks, England)》1995,15(4)
Northern Ireland has a tradition of peat cutting; 78 per cent by area of remaining lowland bogs and 46 per cent of blanket bogs have been cut in the past. Since the early 1980s, machine peat extraction for fuel and horticulture has increased, against a background of changing economic support for agriculture, high rural unemployment and agricultural underemployment. Cutting fuel peat can reduce household fuel costs and some peat fuel is sold to gain income. Horticultural peat is cut mainly for sale. Expansion of machine extraction, with possible environmental impacts, occurred as interest in peatland conservation increased. Potential conflict arises between local economic needs and conservation. Machine cutting for fuel is widespread, but affects only 2.6 per cent of the blanket peat area; horticultural extraction is more localized and is only one-fifth of the extent of fuel extraction. Altitude, distance from roads, land ownership and rights, turbary, religious affiliation, local economic needs and the role of government departments all contribute to explaining the distribution and extent of extraction. 相似文献
8.
This study aimed to establish the effects of waterlogging, salinity and light on the early development of mangroves. Seedlings of Bruguiera gymnorrhiza (L.) Lamk. and Heritiera littoralis Dryand were exposed to 12 weeks of waterlogging, during which time growth and photosynthesis were measured every two weeks. The salinity of the water inundation ranged from fresh water to full-strength sea water (salinity 35). Seedlings were exposed to either full sunlight of 1 500 µmol photon m–2 s–1 (SD 397) at midday or shade conditions of 325 µmol photon m–2 s–1 (SD 40) of light at midday, to explore whether the plants would be differently affected by prolonged waterlogging in increased salinities and under different light conditions. Heritiera littoralis was more sensitive to waterlogging, salinity and light, displaying a least relative growth rate of 0.127 g g–1 week–1 (SE 0.032) under shade, and 0.025 g g–1 week–1 (SE 0.021) in full light; while under shade, photosynthesis continued only in fresh water, but photosynthetic yield decreased from 0.7 to 0.4 with increasing duration of waterlogging. By 12 weeks, all H. littoralis seedlings treated with any saltwater mixture had died. Bruguiera gymnorrhiza seedlings maintained a moderate rate of photosynthesis throughout inundation in both shade and full light, with yields of 0.7 and 0.3, respectively. Furthermore, B. gymnorrhiza survived waterlogging in up to 66% seawater, and maintained comparable relative growth rates of 0.164 g g–1 week–1 (SE 0.066) with 0.083 g g–1 week–1 (SE 0.065) and 0.074 g g–1 week–1 (SE 0.036) with 0.052 g g–1 week–1 (SE 0.037) under shade and in full light between fresh water and the highest salinity conditions, respectively. These results suggest that B. gymnorrhiza is broadly tolerant, making it a potential candidate species for restoring vulnerable mangrove forests. 相似文献
9.
塔里木二叠纪基性-中性-酸性岩浆岩的年代学及其地质意义 总被引：13，自引：9，他引：4
塔里木西部柯坪地区出露的早二叠纪玄武岩与盆地内其他地区广泛分布的玄武岩共同构成一个面积约0.25Mkm2的溢流玄武岩省。巴楚地区出露的早二叠纪辉绿岩、正长岩、石英正长岩与石英正长斑岩等多种岩浆岩构成了连续的基性-中性-酸性岩浆序列。野外露头观察表明,巴楚麻扎尔塔格地区的基性-中性-酸性岩浆岩为近同时侵位。柯坪塔格开派兹雷克组顶部层位玄武岩的锆石SHRIMP U-Pb年龄为279.0±4.5Ma, 该年龄值可限定该区二叠纪溢流玄武岩喷发的最晚时限。巴楚麻扎尔塔格石英正长斑岩脉的锆石SHRIMP U-Pb年龄为273.0±3.7Ma, 与前人测定的巴楚辉绿岩脉和正长岩的锆石年龄在误差范围内一致,表明巴楚地区的基性-中性-酸性岩浆岩为近同时侵位,时间在275Ma左右。综合已发表的塔里木二叠纪岩浆岩高精度年代数据,本文提出：整个塔里木大火成岩省岩浆作用的持续时间约为20Myrs; 291~287Ma喷发的巨量溢流玄武岩可能构成塔里木大火成岩省的主体,是地幔柱头部熔融的直接产物; 283~272Ma侵位的巴楚、一间房和塔北地区的其它类型岩浆岩体积较小,为塔里木大火成岩省晚期岩浆作用的产物。 相似文献
10.
R. Neuhuser A. Koeltzsch St. Raetz T. O. B. Schmidt M. Mugrauer N. Young F. Bertoldi T. Roell T. Eisenbeiss M. M. Hohle M. Va&#x;ko C. Ginski W. Rammo M. Moualla C. Broeg 《Astronomische Nachrichten》2009,330(5):493-503
We report new photometric observations of the ∼200 000 year old naked weak‐line run‐away T Tauri star Par 1724, located north of the Trapezium cluster in Orion. We observed in the broad band filters B, V, R, and I using the 90 cm Dutch telescope on La Silla, the 80 cm Wendelstein telescope, and a 25 cm telescope of the University Observatory Jena in Großschwabhausen near Jena. The photometric data in V and R are consistent with a ∼5.7 day rotation period due to spots, as observed before between 1960ies and 2000. Also, for the first time, we present evidence for a long‐term 9 or 17.5 year cycle in photometric data (V band) of such a young star, a cycle similar to that to of the Sun and other active stars (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献