排序方式: 共有17条查询结果,搜索用时 15 毫秒
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A. Tomás S. Aune T. Dafni G. Fanourakis E. Ferrer‐Ribas J. Galán A. Gardikiotis J. A. García T. Geralis I. Giomataris H. Gómez F. J. Iguaz I. G. Irastorza G. Luzón T. Papaevangelou A. Rodríguez J. Ruz L. Seguí T. Vafeiadis S. C. Yildz 《X射线光谱测定》2011,40(4):240-246
The last generation of micromegas, called microbulk, are ahead of classical gas detectors (or even other kind of micro‐pattern gas detectors) in gain stability, efficiency (by operation at high pressure), simplicity, robustness, energy resolution, readout features and radiopurity. This makes them a competent solution in the field of Rare Event Searches, a field where low background is the most appreciated feature of a detector. The CAST (CERN Axion Solar Telescope) experiment is the best example of their application in the X‐rays range. In CAST, these detectors have achieved background rates as low as 6 × 10?6 counts keV?1 cm?2 s?1. Beyond this nominal operation, there have been several periods where the background has been reduced to a level of 2 × 10?7 counts keV?1 cm?2 s?1, due to reasons which are under investigation. The CAST experiment will be presented, paying special attention to their microbulk micromegas, as well as the procedures to achieve low background. Latest news about the operation of these kinds of detectors for the first time in underground conditions will be advanced here. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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The polyamines, octyl-[2-(2-octylamino-ethylamino)-ethyl]-amine (L1) and octyl-{2-[2-(2-octylamino-ethylamino)-ethylamino]-ethyl}-amine (L2), have been used as anion ionophores in PVC-based membrane ion-selective electrodes. Different electrodes were prepared containing L1, or L2, and o-nitrophenyl octyl ether (NPOE) or bis(2-ethylhexyl)sebacate (DOS) as plasticizers. The response of the electrodes was tested in two different buffers, HEPES-KOH (pH 7) and MES-KOH (pH 5.6). Electrodes containing L1 and L2 with NPOE (E1 and E2, respectively) showed a Nernstian response for thiocyanate with a good response time. The detection limit, linear range and slope for electrode E1 were 3.8 × 10−6 mol dm−3, 1 × 10−5 to 1 × 10−1 mol dm−3 and −57.2 mV decade−1 at pH 5.6 and 4.47 × 10−6 mol dm−3, 1.95 × 10−5 to 1 × 10−1 mol dm−3 and −58.1 mV decade−1 at pH 7.0. For electrode E2 the detection limit, linear range and slope found were 2.63 × 10−6 mol dm−3, 7.94 × 10−6 to 1 × 10−1 mol dm−3 and −58.5 mV decade−1 at pH 5.6 and 1.23 × 10−5 mol dm−3, 7.95 × 10−5 to 1 × 10−1 mol dm−3 and −46.0 mV decade−1 at pH 7. In contrast, electrodes containing DOS as plasticizers gave only response at pH 5.6 (detection limit, linear range and slope at pH 5.6 were 3.16 × 10−5 mol dm−3, 1 × 10−4 to 1 × 10−1 mol dm−3 and −52.6 mV decade−1). Selectivity coefficients for different anions with respect to thiocyanate were calculated. The electrode E2 at pH 5.6 was also used for the determination of SCN− by potentiometric titrations with Ag+ ions with good results. The electrode E2 was also used to determine concentrations of thiocyanate in biological samples. 相似文献
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Carmen Díaz Alexandre Seguí Joan Ribas Xavier Solans Manuel Font-Altaba Andren Solans Jaume Casabó 《Transition Metal Chemistry》1984,9(12):469-473
Summary The new complexes (aa-H2)[CrF4(aa)]Cl, where aa = ethylenediamine, 1,2-diaminopropane or 1,2-diaminocyclohexane, have been systematically synthesized and characterized. The crystal structure of (en-H2)[CrF4(en)]Cl (en = ethylenediamine) has been resolved indicating that the four fluorine atoms are ligands and the chloride is ionic. The cation is the diprotonated ethylenediamine ligand. Synthesis of the analogous complex with 1,3-diaminopropane (tn) failed. The hydrolysis of these complexes with concentrated HBr give compounds of formula [CrF2(H2O)2(aa)]Br, which upon solid phase heating yield the dehydrated [CrF2Br(H2O)(aa)]. 相似文献
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Dynamic ligand exchange-affinity capillary electrophoresis (DLE-ACE) is introduced as a convenient platform for assessing the conformational stability and relative affinity of a holoprotein to different ligands without off-line sample pretreatment, since ligand exchange and protein unfolding processes are integrated in-capillary during electromigration. 相似文献
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M. V. Cougo-Pinto C. Farina Antonio J. Seguí-Santonja 《Letters in Mathematical Physics》1994,30(2):169-171
We show that a slight modification in Schwinger's method leads directly to the finite result for the Casimir energy of a massless scalar theory. 相似文献
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Coll C Labrador RH Mañez RM Soto J Sancenón F Seguí MJ Sanchez E 《Chemical communications (Cambridge, England)》2005,(24):3033-3035
A remarkable enhanced response towards the hydrophilic anion sulfate using plasticized PVC membranes containing the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate and a polyazacycloalkane derivative as ionophore has been found. 相似文献