Also known as: white damp Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They...
Also known as: OPCW Written by André Munro André Munro is a regular freelance contributor as well as a former editor at Encyclopaedia Britannica. He holds a Ph.D. in Political Science (Northwestern University) and has written numerous articles... ...
need to validate it first as a bona fide chemical probe. Biologists are used to validating their reagents: shRNAs or antibodies, etc, and they know the importance of selectivity and controls. They also need to think hard about off-targets and controls for chemical probes, and they need to v...
The risin and tannin that can be extracted from it are sought by thechemicalindustry. 从中提取的松香和鞣酸是化学工业上很需要的. 《简明英汉词典》 The explosion of thechemicalplant has poisoned many local residents. 那座化工厂的爆炸毒死了许多当地居民. ...
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In the permeation testing mode, the weight of the entire assembly is monitored; however, for use as degradation test, the test cell serves as a convenient means for evaluating changes in material mass and thickness. Visible observations are also recorded as part of the testing protocol. The ...
The chemical composition of rainfall changes slightly as clouds move. Most hydrogen and oxygen atoms in water are stable but traces of both elements are also present as heavier isotopes (同位素) . The heaviest raid(列阵)falls first. As a result storms that form over the Pacific deliver heavier...
The measurements also exhibit the presence of quartz together with feldspars in most of the gloss specimens. Although these minerals can be present in the gloss itself, part of the signal presumably comes from the underlying ceramic body, as the X-rays penetrate a little deeper than the thickne...
also clarified the concept of “element” into a modern generalization, that it was a substance that could not be broken down, and this too supported his theory. Soon after, studies of gases by English chemistJohn Dalton, and the first table ofatomic weightsthat Dalton compiled, as well as...
bring about chemical changes, and some of theproducts of a modern refinery complex are chemicals by any definition. The termpetrochemicalis used to describe these chemical operations, but, because they are often carried out at the same plant as the primary distillation, the distinction between petr...