The equivalent conductivities of two aqueous silicate species, [SiO(OH)3]− and [SiO2(OH)2]2−, are fundamental to understanding many physico-chemical phenomena of silicate materials in electrolyte solutions. These phenomena include diffusion, adsorption, and phase transformations. But significant inconsistencies have been presented in published equivalent conductivities of the two silicate aqueous ions. Also, little work has so far been undertaken to discuss how aspects, such as temperature and solution composition, may influence electrolytic conductivity of silicate aqueous solutions. This work presents the equivalent conductivities of the two silicate species, measured with electrochemical impedance spectroscopy (EIS) from 277.85 K to 308.45 K. A conductivity model for mixed electrolytes of high alkaline was first established. This model was then verified with the electrolyte conductivities of NaOH-H2O solutions and NaOH-Na2CO3-H2O solutions. Next, the equivalent conductivities of [SiO(OH)3]− and [SiO2(OH)2]2−, were calculated by solving the overdetermined equation groups for different temperatures, based on electrolyte conductivities of NaOH-Na2SiO3-H2O solutions. The accuracy of both calculations and measurements are examined in depth from various viewpoints. This work presents essential inputs for quantitatively understanding multiple physico-chemical properties of silicate materials in electrolyte solutions.

Radar is now widely used in human activity classification because of its contactless sensing capabilities, robustness to light conditions and privacy preservation compared to plain optical images. It has great value in elderly care, monitoring accidental falls and abnormal behaviours. Monostatic radar suffers from degradation in performance with varying aspect angles with respect to the target. Bistatic radar may offer a solution to this problem but finding the right geometry can be quite resource-intensive. We propose a bespoke simulation framework to test the radar geometry for human activity recognition. First, the analysis focuses on the monostatic radar model based on the Doppler effect in radar. We analyse the spectrogram of different motions by Short-time Fourier analysis (STFT), and then the classification data set was built for feature extraction and classification. The results show that the monostatic radar system has the highest accuracy, up to 98.17%. So, a bistatic radar model with separate transmitter and receiver was established in the experiment, and results show that bistatic radar with specific geometry configuration (CB2.5) not only has higher classification accuracy than monostatic radar in each aspect angle but also can recognise the object in a wider angle range. After training and fusing the data of all angles, it is found that the accuracy, sensitivity, and specificities of CB2.5 have 2.2%, 7.7% and 1.5% improvement compared with monostatic radar.

Water molecules exist as two spin isomers, differing by the relative orientation of the nuclear spins of the two hydrogen atoms: either antiparallel (para-water, S=0) or parallel (ortho-water, S=1) [1]. The transition between these nuclear spin states can be achieved through magnetic symmetry breaking via a field gradient across the spins applied by a suitably placed magnetic moment for a sufficiently long time [2]. The contradictory mechanisms of interaction between water or an aqueous solution and magnetic field were reviewed, especially the one expanded on Dynamically Ordered Liquid Like Oxyanion Polymers (DOLLOP) [3]. Then the state of art agreements that have been proved by reproductive experiments or theories were discussed. A new hypothesis for the magnetic effects on the interconversion of nuclear spin isomers of water at the interface of water-O2 was proposed, as well as its applicability in the structure modification of C-S-H.