• In eighteen ninety-seven, a chemist named Felix Hoffmann at Friedrich Bayer and Company in Germany created acetyl salicylic acid.

    VOA: special.2009.10.20

  • So just keep in mind when you do see the chlorine in these drugs, it's very different from the acid chloride.


    麻省理工公开课 - 化学原理课程节选

  • They're derived from a precursor called triacylglyceride, which is as glycerol molecule with three fatty acid chains dangling off of it.


    耶鲁公开课 - 生物医学工程探索课程节选

  • But Mister Zundt says reducing air pollution and acid rain will reduce respiratory illnesses for people in the city.

    VOA: special.2009.09.07

  • And they wanted to use a soluble salt of citric acid, so they could have used sodium, they could have used potassium.


    麻省理工公开课 - 化学原理课程节选

  • The experts said women who wish to become mothers should take folic acid to prevent problems in their babies.

    VOA: special.2009.04.21

  • You know, you mix acid and base together and the thing heats up like crazy, right.


    麻省理工公开课 - 热力学与动力学课程节选

  • We stopped in the afternoons to fish for a few minutes in little rivers turned black by the acid of cypress trees.

    VOA: special.2010.01.30

  • HF And let's take an example, HF, hydrofluoric acid, all right?


    麻省理工公开课 - 固态化学导论课程节选

  • At the same time, doctors warn that acid in aspirin can cause bleeding in the stomach and intestines.

    VOA: special.2009.10.20

  • Fatty acid chains are fat molecules, they behave, if you have a lot of them in solution like oil.


    耶鲁公开课 - 生物医学工程探索课程节选

  • Domoic acid can also cause neurological disorders and death in animals that eat fish poisoned with the neurotoxin.

    VOA: special.2011.03.15

  • And what it's used is to convert one type of group, what's called a carboxylic acid into another type of very reactive intermediate, which is called an acid chloride.


    麻省理工公开课 - 化学原理课程节选

  • Boric acid has been used to kill other insects including cockroaches, termites and ants inside homes since the middle of last century.

    VOA: special.2011.02.23

  • They have two fatty acid chains and so these are the oily like parts of the molecule, the molecules that behave like oil.


    耶鲁公开课 - 生物医学工程探索课程节选

  • "It contributes to smog,acid rain, loss of biodiversity, dead zones along the coast, global warming, stratospheric ozone depletion.

    VOA: special.2011.04.05

  • So I show that here, so in green, you have what's called a carboxcylic acid group, a c o o h, which gets converted by s o c l 2 to a c double bond o c l or an acid chloride.


    麻省理工公开课 - 化学原理课程节选

  • Soil should also be tested for its pH level, a measure of the acid and alkaline balance.

    VOA: special.2009.06.09

  • And then linked to the glycerol instead of a third fatty acid chain is a water soluble molecule, like a salt.


    耶鲁公开课 - 生物医学工程探索课程节选

  • Later,the water and most of the acid left the caves as the Guadalupe Mountains continued to rise.

    VOA: special.2009.12.07

  • She needs to know this enzyme works by both acid base chemistry, and oxidation reduction.


    麻省理工公开课 - 化学原理课程节选

  • Yet,it took some time for the team to confirm that the amino acid glycine came from space.

    VOA: special.2009.09.30

  • Proteins are only susceptible to phosphorylation if they have certain kinds of amino acid sequences.


    耶鲁公开课 - 生物医学工程探索课程节选

  • Scientists are testing bone from Nikumaroro to learn if DNA, deoxyribonucleic acid, can be recovered from it.

    VOA: special.2011.01.18

  • One of them has the right sequence of codons to specify the amino acid sequence of the protein, and the other one has a complimentary sequence.


    耶鲁公开课 - 生物医学工程探索课程节选

  • But it is the first time an amino acid has been discovered on a comet.

    VOA: special.2009.09.30

  • They would naturally hybridize and form a duplex, or a double stranded nucleic acid.


    耶鲁公开课 - 生物医学工程探索课程节选

  • Then they made small changes to the bacterium's deoxyribonucleic acid -- DNA for short.

    VOA: special.2010.07.20

  • They bring into proximity an amino acid so that instead of forming a new polymer of a nucleic acid, a polymer of an amino acids is formed.


    耶鲁公开课 - 生物医学工程探索课程节选

  • In the eighteen hundreds, researchers discovered how to make salicylic acid from the chemical.

    VOA: special.2010.12.14


amino acid n. [化]氨基酸

acetic acid [化]醋酸,乙酸

sulfuric acid 硫酸

fatty acid [化]脂肪酸

lactic acid 乳酸

phosphoric acid [化]磷酸

acrylic acid 丙烯酸

hydrochloric acid 盐酸

citric acid 柠檬酸

nitric acid [化]硝酸

sulphuric acid 硫酸

acid rain 酸雨

hyaluronic acid [生化]透明质酸;玻璃酸

organic acid 有机酸

nucleic acid [生化]核酸

benzoic acid [化]苯甲酸

acid solution [化]酸溶液

lactic acid bacteria 乳酸菌

acid content 酸性含量

oxalic acid [化]草酸

- 来自原声例句

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进来说说原因吧 确定