Remote determination of substances, including liquids, is an urgent problem, the solution of which requires fundamentally new approaches to both methods and measurement techniques. This is due to the fact that standard liquid analysis methods are mainly spectroscopic methods in various frequency ranges from neutron diffractometry to acoustic spectroscopy, which are very difficult or even impossible to apply in remote sensing. Conventional radar methods are usually unacceptable due to the impossibility of covert removal of information using active location and obtaining data on the composition of the irradiated object based on it. Therefore, at present, methods and techniques of passive location are being used more and more, but in order to solve quite specific problems of remote identification of substances, they must be significantly modernized.
This article discusses a technique and a modernized measuring complex for remote study of liquid electrolytes and non-electrolytes using measurements and subsequent analysis of fluctuations in the temperature difference of the intermediate liquid medium (distilled water) in which the container with the liquid under study is located. To date, there is no clear understanding of how thermally stimulated radiation depends on the composition of a macroscopic body, and also on whether thermal radiation is in equilibrium or non-equilibrium. The investigated object, at a given temperature, emits electromagnetic waves associated with the thermal motion of the molecules and atoms of its constituents. That’s, why thermal radiation is random (fluctuation) process, which means that the average value of the electromagnetic field is equal to zero, but other averaged features, such as quadraticity in the field, may differ from zero. The quadratic characteristics of a thermal electromagnetic field determine its energy, which has a finite value other than zero, which can be measured by an appropriate sensor and characterizes the field source — a macroscopic body heated to a certain temperature. The paper presents the results of studies of mixtures of electrolytes and non-electrolytes of various concentrations. An example of non-equilibrium thermal radiation is given. It is shown that it is possible to distinguish between the studied liquids and methods of combining the components of solutions of given concentrations to obtain the given properties of the entire solution.
