Results 331 to 340 of about 3,443,174 (389)

Carbon Chemistry of Apollo 14 Size-fractionated Fines

Nature Physical Science, 1972
TOTAL carbon measurements of crystalline lunar rocks returned by the Apollo missions have revealed only low concentrations of carbon (10–50 p.p.m.)1–3. The breccias and fines, however, have, in general, higher carbon concentrations (up to 200 p.p.m.). This carbon is more concentrated in the finer fractions1 and is correlated with the noble gas content ...
P. T. HOLLAND, B. R. SIMONEIT, P. C. WSZOLEK, W. H. MCFADDEN, A. L. BURILINGAME   +4 more
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Understanding of asphalt chemistry based on the six-fraction method

Construction and Building Materials, 2021
Abstract Characterization of asphalt chemistry has been a longstanding challenge in the field of pavement engineering. The commonly used SARA approach fails to fully describe the macroscale property of asphalt, and the chemical properties of the individual fractions in asphalt are rarely studied so far.
Xin Qu, Zepeng Fan, Tianshuai Li, Bin Hong, Yang Zhang, Jianming Wei, Dawei Wang, Markus Oeser   +7 more
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Medicinal Chemistry Meets Proteomics: Fractionation of the Human Plasma Proteome

Current Medicinal Chemistry, 2013
Human plasma and its fractions/derivatives are frequently used materials in biomedicine as it contains thousands and thousands of proteins representing the majority of human proteome. Several important methods were developed in the past for the fractionation of this important biological fluid and its use for medicinal purposes.
A, Kovàcs, A, Guttman
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Mineralogy and fluid chemistry controls on lithium isotope fractionation during clay adsorption

Science of The Total Environment, 2022
Our current understanding of controls on δ7Li variability and fractionation mechanisms is limited, complicating the interpretation of chemical weathering. The role of clay adsorption in Li isotope fractionation during chemical weathering has been confirmed.
Wenshuai, Li, Xiao-Ming, Liu
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The Chemistry of High Molecular Weight Fulvic Acid Fractions

Canadian Journal of Chemistry, 1974
Fulvic acid (FA) was methylated, dissolved in benzene, and fractionated over Al2O3 with the aid of organic solvents of increasing polarities. This paper is concerned with fractions eluted with ethyl acetate (III), ethyl acetate — methanol (1:1) (IV), and methanol (V), which were quantitatively the most abundant ones and which we consider as being most
Jean A. Neyroud, Morris Schnitzer
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Comments on ‘‘Introduction to the chemistry of fractionally charged atoms: Electronegativity’’

Physical Review D, 1987
A comparison is made between the electronegativities of ``quark atoms'' as predicted by a recent article, and those suggested by traditional chemical methods. It is shown that the neglect of valence-state considerations for the ionization energies and electron affinities produces serious errors in calculating electronegativities by the Mulliken method.
, Liebman, , Huheey
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RESID HYDROTREATING CHEMISTRY Analyses of Hondo Feed and Product Fractions

Fuel Science and Technology International, 1990
Abstract The chemistry of resid upgrading was studied by following the changes caused by hydrotreatment of Hondo 450°F+ resid, its separated asphaltenes and maltenes, and polar, aromatic, and saturate fractions. Both continuous and batch hydrogenations were studied, using two commercial resid hydrotreating catalysts.
Judith C. Ware, Geoffrey E. Dolbear
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Fluoride precipitates in silicate wet-chemistry: implications on REE fractionation

Chemical Geology, 1993
Abstract Precipitates of hieratite, ralstonite and NaUZr2F12 form during HFHNO3HClO4 dissolution of dolerite samples. These minerals are responsible for fractionation of Sm and Nd from the solution, giving rise to spurious analytical results. Fractionated Sm and Nd can be recovered by dissolution of hieratite in hot (373 K) water or HCl.
R.H. Boer, G.J. Beukes, F.M. Meyer, C.B. Smith   +3 more
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Association of ions and fractional crystallization: a general chemistry experiment

Journal of Chemical Education, 1983
The experiment in this article has been used in laboratories for non science majors and for inorganic chemistry. In both cases students attain a good understanding of what it taking place, how the various procedures affect actual concentrations of ions present, and why particular salts crystallize under certain conditions whereas others do not.
Charles W. J. Scaife, Richard L. Dubs
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Increasing contribution of nighttime nitrogen chemistry to wintertime haze formation in Beijing observed during COVID-19 lockdowns

Nature Geoscience, 2023
Chao Yan, Y. J. Tham, W. Nie, Men Xia, Haichao Wang, Yishuo Guo, Wei Ma, Junlei Zhan, Chenjie Hua, Yuanyuan Li, C. Deng, Yiran Li, Feixue Zheng, Xin Chen, Qinyi Li, Gen Zhang, A. Mahajan, C. Cuevas, D. Huang, Zhe Wang, Yele Sun, A. Saiz‐Lopez, Federico Bianchi, V. Kerminen, D. Worsnop, N. Donahue, Jingkun Jiang, Yongchun Liu, A. Ding, M. Kulmala   +29 more
semanticscholar   +1 more source