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Based on the first ionization chamber (IC) prototype, the structure, working gas component and electrode material of the IC are improved. The test of the improved IC shows that the plateau length is about 2000 V, the plateau slope is less than 0.2%/100 V, the sensitivity is 19.6 pA/rad·h-1, the up-limitation of the linearity can be up to 3.6×105 rad/h, and the applied voltage can be operated to 3500 V. The test results show that the performance of the improved IC meets the requirements of the beam loss monitor. 相似文献
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The aim of this paper is to present a theoretical study of the aerosol penetration
through an electret fibrous filter, using a numerical approach. The aerosol sizes
considered in this study were in the submicron range, and in the numerical model,
the conventional mechanical mechanisms (impaction, interception, diffusion and
gravitationally settling) were taken into consideration along with the electrostatic
mechanisms, including the Coulombic and dielectrophoretic effects. The aerosol
penetration through an electret fibrous filter is heavily dependent on the aerosol
penetration of a single fibre. The aerosol penetration through a single electret
fibre under various filtration conditions was calculated. The effects of aerosol
diameter, aerosol and fibre charge state, face velocity, packing density and aerosol
dielectric constant on the aerosol penetration were investigated. 相似文献
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Linear Mo-Fe-S cluster complexes with basic unit of MoS_4 can be divided into four types ac-cording to the central Mo-S skeleton (S_2MoS_2Fe, S_2MoS_2FeS_2MoS_2, S_2MoS_2FeS_2Fe, FeS_2MoS_2Fe).Ten such complexes with various ligands and cations were synthesized, and their crystal structureswere determined and characterized by electron spin resonance, infrared and electron absorptions,Mossbauer and magnetic effects. Atomic distances from crystallographic analysis were comparedsystematically with respective spectroscopic data. There is strong evidence indicating that electrontransfers from Fe(Ⅱ) to Mo(Ⅵ), in spite of the fact that the apparent oxidation state of molyb-denum in most of the aforementioned complexes remains six. The probability of this electrontransfer depends strongly on the environment of Fe(Ⅱ). The fact that MoS_4~(2-) is both a goodbidentate ligand and an effective electron transfer unit is also evidence for its presence in manymolybdoenzymes and as a catalytically active center. 相似文献
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1 INTRODUCTION Chemistry of manganese cluster has become an attractive research field because of the involvement of manganese in several biological redox-active sys- tems[1,2], especially in the oxygen-evolving complex (OEC) of photosystem Ⅱ (PSⅡ) in green plants[3]. It was thought that the coordination environment of Mn in OEC contains O and N donors, and the bind- ing of aqua to the Mn site may be important to the oxidation of aqua for the evolution of dioxygen[4, 5]. In recent … 相似文献
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Itiswellknownthatinnaturetheactivationandreductionofdinitrogeninairtoammoniaarecatalyzedbynitrogenaseatambienttemperatureandpressure.ThemaincomponentsoftheactiveclusterofMoFeproteininnitrogenaseareMcluster(MoFe7S9cluster)andPcluster(Fe8S8cluster)[1].Inthel… 相似文献
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The mononuclear manganese complex Mn(phen)(CF3COO)(H2O)3(NO3 (C14H14O8N3F3Mn) has been synthesized, where phen = 1,10-phenanthroline. The molecular and crystal structures were determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/c with a = 8.8550(3), b = 10.6529(3), c = 19.8763(2) A, β = 97.762(2)o, V = 1857.78(8) A3, Z = 4, Mr = 464.22, Dc = 1.660 g/cm3, μ = 0.789 mm-1, F(000) = 940, T = 293(2) K, R = 0.0764 and wR = 0.2441 for 1995 observed reflections with I > 2σ(I). In the crystal the manganese atom is six-coordinated by two chelated nitrogen atoms from phenanthroline, three oxygen atoms from water molecules and one oxygen atom from trifluoroacetate, completing an octahedral geometry. 相似文献