نتایج جستجو برای: different acids such as sulfuric
تعداد نتایج: 6805291 فیلتر نتایج به سال:
Bergmann and Stein (1) have described a procedure for the isolation and purification of naturally occurring n-leucine based upon the precipitation and recrystallization of the slightly soluble salt of this amino acid with naphthalene-fi-sulfonic acid. The product obtained was stated to be 97 per cent pure and to be free from methionine, a common contaminant of less pure preparations of n-leucin...
molybdate sulfuric acid (msa) has been prepared and used as catalyst for the biginelli synthesis of some quinazolinones/thiones under solvent-free conditions. the catalyst loading is low and it shows recyclability. this method has advantages such as avoidance of the organic solvents, high yield of pure products, short reaction times and operational simplicity.
With the purpose of obtaining the real and imaginary parts of the complex refractive index N; = n + ik, we have made quantitative measurements of spectral transmission and reflection of sulfuric acid solutions in the visible and near infrared. On the basis of the results, we have obtained values for n throughout the entire region and values of k in the near infrared together with upper limits f...
A comparison of laboratory spectra with Galileo data indicates that hydrated sulfuric acid is present and is a major component of Europa's surface. In addition, this moon's visually dark surface material, which spatially correlates with the sulfuric acid concentration, is identified as radiolytically altered sulfur polymers. Radiolysis of the surface by magnetospheric plasma bombardment continu...
abstract birbery and corruption and other criminal and as such is one of social phenomena , and i can firmly say that society is protected and safe from harm , this is criminal . eache community is familiar with these crimes and the crime associated ( direct or indirect ) with the political economic , social , and cultural beliefs and religious issues , especially with the community . admitted...
G . H evesy has written that [6] 1 " In view of the I.great similarity b etween hafnium and zirconium, i t ris hardly possible to separate these two elements in a lsingle operation ." A simple one-step separation c adequ a te for analytical work has still to be developed for hafnium-ziTconium mixtures, although recent work employing ion exchange has developed suitable methods for the separation...
the images of muslims in media, literature and politics have been mostly black and white portrayals of a people alien to modernity, civilization, rationality and pluralism. since the end of the cold war and the onset of deadly terrorist attacks in different areas of the world, especially in the united states, these representations show a palpable difference: muslims are represented not only as ...
Harmonic and anharmonic vibrational frequency calculations are reported for the most stable hydrogen bonded complexes formed between the hydroperoxyl radical and formic, acetic, nitric, and sulfuric acids which are of atmospheric interest. A comparison between the calculated IR spectra of the hydrogen bonded complexes with the corresponding separate monomers is also reported with the aim to fac...
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