Single-crystal neutron diffraction, ab initio calculations and Raman spectroscopy are applied to understand the structure and hydrogen bonding of ammonium carbonate monohydrate, a hitherto poorly characterized substance, particularly in relation to other ammonium-bearing compounds.
In his opinion, there are two fundamental modes of being proper to things: being by itself, which characterizes substances, and being or inhering in something else, which characterizes accidents.
Careful weighing combined with an application of the law of constant proportions allowed chemists to characterize substances in terms of the mass ratios of their constituent elements, which is what chemists mean by the composition of a compound.
Any such property would characterize substances (rather than other properties, or states, or abstract objects); it would be a property that could characterize a simple thing; it would be an internal (or, as some might prefer to say, "intrinsic") property of anything it characterized -- thus a thing existing in isolation could have such a qualitative property.
The objective of this study was to develop tools for characterizing substances that mediate estrogenic activity in complex mixtures, that is, to determine if the estrogenic compounds were ER activators by direct binding (with high or low affinity) or ER activators by another mechanism of action (AhR activation).
Because respiratory sensitization is widely regarded as an adverse effect of much concern and substantial morbidity, and in order to implement necessary prevention and control procedures, considerable efforts have been made to develop methods to identify and characterize substances that act as respiratory sensitizers, with particular concerns for workplace chemicals.
Only 29.5% reported descriptive statistics characterizing substance use within the study sample and only 7.7% reported substance use-related outcomes.
Writers like René Descartes and Benedict de Spinoza were convinced that it was the task of the metaphysician to seek for and characterize substance understood in this sense; the more mundane substances with which physical scientists were concerned were, in their opinion, only marginally relevant in this inquiry.
First, there are the issues concerning how to characterize substance in contradistinction to properties and the other categories.
(i) The first attempts to clarify what characterizes substance, and therefore what falls by itself into that category; (ii) the second is concerned with the distinction between primary (or individual) and secondary (or universal) substances.
The text of the Monadologie more accurately reflects Leibniz's considered position because it only characterizes simple substances as "substances".
