No abstract

In electrochemical devices such as solid oxide cell stacks, many physical phenomena are interacting on many different length scales in an intricate geometry. Modeling is a strong tool to understand the interior of such devices during operation, enhance their design and investigate long-term response (degradation). Computations can however be challenging as the many geometric details and coupled physical phenomena require a significant computational power, and in some cases, even state-of-the-art clusters will not be sufficient. This hinders the use of the models for the further development of the technology. In this work, we present an original type of solid oxide cell stack model, which is highly computationally efficient, resulting in computations which are two orders of magnitude faster than the conventional type of stack models with all geometric details explicitly represented. In the model presented here, the geometric details are implicitly represented by using the so-called homogenization. The resulting homogeneous anisotropic media provides the correct overall response (temperature, species, molar fractions, etc.) Local details as the mechanical stress in the electrolyte are not represented explicitly. These can be retrieved by localization through submodels (multiscale model), in some cases without loss of computational efficiency, as

A light spot that is smaller than a half wavelength will subsequently diverge in all directions. In this letter, the authors model a subwavelength (0.42λ) super-resolution light beam which propagates over a long distance without any divergence. This can be achieved by placing a multibelt pure-phase-type binary optical element on the lens pupil. The authors also report a useful approach for designing the optical element, based on vector diffraction theory, which can be used in paraxial and nonparaxial focusing and imaging systems.

Co-ferrite films were prepared using pulsed laser deposition at low substrate temperatures in this work. Magnetic properties of these films have been investigated in the function of substrate temperature and film thickness. A perpendicular coercivity as high as 12.5kOe has been achieved in the Co-ferrite film with a thickness of 33nm deposited at 550°C. The high coercivity mechanism is possibly associated with nanocrystalline structure, textured structure, and presence of relatively large residual strain.

No abstract