Our previous work shows that the use of two time-varying anisotropic layers on the basis of transformation optics can calculate the electric field in microwave applicators of regular shapes with moving elements in translation accurately and efficiently. However, it is difficult to deal with applicators of irregular shapes, which is widely used in practical applications. In this article, we extend this work to the calculation of electric field in applicators of irregular shapes. In the proposed two-dimensional model, the motion region is truncated by rectangular anisotropic coated layers, including four edge layers and four corner layers. In this case, the motion region is independent of applicator shapes. Therefore, the electric field can be calculated equivalently with arbitrary irregular applicator shapes. The results show good accuracy and efficiency, which indicates that the improved method has a good potential for modeling the heating process of practical microwave applicators with elements in translation.
Single crystalline planner gold nanostructures, including nanogears, nanobelts and nanoplates, are synthesised in hexagonal lyotropic liquid crystals made of P123/HAuCl4 aqueous solution. The effects of reaction temperature as well as capping agent on the growth of nanoproducts are studied in detail. When cetyltrimethyl ammonium bromide is used as the capping agent, gold nanobelts appear in the products at 45°C, while gold nanogears can be obtained with a large scale at room temperature when poly(N-vinyl-2-pyrrolidone) is the capping agent. Results show that temperature is an important factor that may influence the growth of gold nanoproducts through changing the lyotropic liquid crystal structure and the adsorption process of capping agent on nanocrystal surfaces. The growth mechanism of nanostructures is further certified by the products from the microwave assistant method.
For the nonlinearly phenomena on the dielectric properties of dimethyl sulfoxide (DMSO)–ethanol mixtures under a low intensity microwave field, we propose a conjecture that there exist some abnormal molecular clusters. To interpret the mechanism of abnormal phenomena and confirm our conjecture about the existence of abnormal molecular clusters, an in-depth investigation about the structure evolutions of (DMSO)m(C2H5OH)n (m = 0–4; n = 0–4; m + n ≤ 4) molecular clusters induced by external electric fields has been given by using density functional theory. The results show that there exist some binary molecular clusters with large cluster radii in mixtures, and some of them are unstable under exposure of electric fields. It implies that the existence of certain abnormal molecular clusters in DMSO-ethanol mixtures results in their abnormality of dielectric properties.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
In experiments on the pulse radiolysis of crystalline D/sub 2/O ice at a nominal temperature of 6 K, yields of e/sup -//sub v/is, e/sup -//sub i/r and the OD radical have been measured as a function of accumulated dose. The yield of e/sup -//sub i/r shows a large effect of dose, increasing from Gepsilon-c = 1.03 x 10/sup 4/ (Gapprox. =0.27) for a previously unirradiated crystal to Gepsilon-c = 4.1 x 10/sup 4/ (Gapprox. =1.08) for a sample that had received 300 krad. The effect of dose is decreased to about half by annealing at 12.5 K, but can only be completely eliminated by annealing above 100 K. The effect is interpreted as being due to the scavenging, by D and OD, of D/sub 2/O/sup +/ which otherwise recombines with e/sup -//sub q/f. The G of OD at 6 K for a previously unirradiated crystal was measured as 3.8; this is much higher than the previously reported G of OH from ..gamma..-irradiated H/sub 2/O ice at 4 K.
Moving elements have been widely used in microwave applicators to improve heating uniformity. However, elements in periodic motion can lead to temperature oscillations in the process of heating. In this case, the processed samples are difficult to reach target temperature and the control system may also become unstable. Aiming at overcoming these problems, we investigate the temperature response of the heating process in microwave applicators with elements in periodical motion in this article. By modeling periodical motion as a periodical heat source, the temperature characteristics can be obtained by solving the heat transfer equation with eigenfunction expansions. The results show that the amplitude of temperature oscillations decreases with angular velocity of the element's motion, which is verified by experiments. It means that temperature oscillations can be reduced by increasing the element's velocity, which is helpful to improve the heating performance in microwave applicators.
The aim of this letter is to propose full-wave calculation of microwave (MW) applicators with elements in translation based on transformation optics. In the proposed 2-D model, the motion region is surrounded by two slabs with time-varying anisotropic homogenous media on the basis of transformation optics: one is to compress the electric field and the other is to stretch the electric field. Thus, the electric field of applicators with elements in translation can be equivalently calculated by full-wave analysis without any remeshing steps. It is helpful to model the heating process of food or biological package transportation on conveyor belts in industrial MW heating accurately and efficiently.
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