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Detection of hypophosphite, phosphite, and orthophosphate in natural geothermal water by ion chromatography 总被引:3,自引:0,他引:3
McDowell MM Ivey MM Lee ME Firpo VV Salmassi TM Khachikian CS Foster KL 《Journal of chromatography. A》2004,1039(1-2):105-111
Current doctrine states that phosphorus is incorporated into cells in the pentavalent(V) oxidation state as orthophosphate. However, recent studies show that microorganisms contain enzymes used to metabolize reduced forms of phosphorous, including phosphite(III) and hypophosphite(I), which suggests that there is a natural source for these chemical species. This paper will discuss suppressed conductivity ion chromatography methods developed to detect hypophosphite, phosphite, and orthophosphate in a geothermal water matrix containing fluoride, chloride, bromide, nitrate, hydrogen carbonate and sulfate. All peaks were clearly resolved, and calibrations were linear with estimated 3sigma detection limits of 0.83, 0.39, and 0.35 microM for hypophosphite, phosphite, and orthophosphate, respectively. 相似文献
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E S Ivey G P Nerbonne G C Tolhurst 《The Journal of the Acoustical Society of America》1987,81(2):370-375
The sound attenuation characteristics of two military helmets were measured using an acoustic manikin as the test apparatus. The manikin results are compared to the results of attenuation measurements made on human subjects wearing identical helmets. The testing room and instrumentation were the same for both the manikin and human subjects. Procedures in ANSI S3.19-1974 were used in the real-ear attentuation at threshold (REAT) part of this study. The results are encouraging as they suggest that the manikin may be used in place of a panel of human subjects to evaluate the hearing protection characteristics of military head gear. 相似文献
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Nicolas Droushiotis Uttam Doraswami Douglas Ivey Mohd Hafiz Dzarfan Othman Kang Li Geoff Kelsall 《Electrochemistry communications》2010,12(6):792-795
A phase inversion process was used to co-extrude cerium–gadolinium oxide (Ce0.9Gd0.1O1.95)/NiO–CGO dual-layer hollow fibres (HF), which were then sintered to form, respectively, the electrolyte and high porosity anode precursor of a solid oxide fuel cell (SOFC) with anode inner diameter of 0.8 mm. Graded CGO–lanthanum strontium cobalt ferrite (La0.6Sr0.4Fe0.8Co0.2O3) cathode layers were then painted onto the CGO electrolyte to form a micro-tubular HF-SOFC. With a carefully designed anode current collector, this produced maximum power densities of 1186–5864 W m? 2 at 450–570 °C. High magnification imaging analysis revealed large three-phase boundary regions within the anode, a dense electrolyte layer and clearly highlighted the multiple CGO–LSCF cermet and pure LSCF cathode layers. The performance of the HF-SOFC with a twenty millimetre active length showed no degradation after four thermal cycles between 300 °C and 570 °C. 相似文献
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CM Thaker S Rayaprol Krushna Mavani DS Rana MS Sahasrabudhe SI Patil DG Kuberkar 《Pramana》2002,58(5-6):1035-1039
The effect of simultaneous substitution of a fluctuating cation and a divalent cation in LaMnO3 perovskite modifies the properties of the material to exhibit large valence colossal magnetoresistance (CMR) effect. A good
example of these properties is (La1−2x
Pr
x
Ca
x
)MnO3 (LPCMO) type CMR material. In this communication it is reported that, with the increase in x (for x=0.1, 0.15, 0.2), the T
c varies between 100 and 120 K with improvisation in metal-insulator transition. Interestingly, resistance increases with x from few hundred ohms to few kilo ohms with corresponding decrease in the unit cell volume. The results of the studies using
X-ray diffraction (XRD), electrical resistivity, magnetoresistance and ac susceptibility measurements on LPCMO samples for
understanding the structural, transport and magnetic properties are discussed in detail. 相似文献
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Dr. Yanira Méndez Dr. Aldrin V. Vasco Galway Ivey Ana Laura Dias Dr. Peter Gierth Bárbara B. Sousa Dr. Claudio D. Navo Angel Torres-Mozas Dr. Tiago Rodrigues Dr. Gonzalo Jiménez-Osés Prof. Gonçalo J. L. Bernardes 《Angewandte Chemie (International ed. in English)》2023,62(44):e202311186
Multicomponent reactions are of utmost importance at generating a unique, wide, and complex chemical space. Herein we describe a novel multicomponent approach based on the combination of the isonitrile-tetrazine (4+1) cycloaddition and the Ugi four-component reaction to generate pyrazole amide derivatives. The scope of the reaction as well as mechanistic insights governing the 4H-pyrazol-4-imine tautomerization are provided. This multicomponent process provides access to a new chemical space of pyrazole amide derivatives and offers a tool for peptide modification and stapling. 相似文献
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Using the methods of moving frames and exterior differential systems, we show that there exist Hopf hypersurfaces in complex
hyperbolic space with any specified value of the Hopf principal curvature α less than or equal to the corresponding value for the horosphere. We give a construction for all such hypersurfaces in terms
of Weierstrass-type data, and also obtain a classification of pseudo-Einstein hypersurfaces in .
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