Screw dislocation pileups in a two-phase thin film

The method of continuously distributed dislocations is used to study the distribution of screw dislocations in a linear array piled up near the interface of a two-phase isotropic elastic thin film with equal thickness in each phase. The resulting singular integral equation is solved numerically using the Gauss–Chebyshev integration formula to arrive at the dislocation distribution function and the number of dislocations in the pileup.

Конструкции блокирующих слоев для подавления паразитной рекомбинации в мощных диодных лазерах с GaAs волноводом

Using numerical simulation, a search is carried out for designs of asymmetric barrier layers (ABLs) for a laser diode having GaAs waveguide and emitting at the wavelength λ = 980 nm. A pair of ABLs, adjoining the active region on both sides, blocks undesired charge carrier flows and suppresses parasitic spontaneous recombination in the waveguide layers. Optimal designs of ABLs based on AlGaAsSb and GaInP for blocking electrons and holes, respectively, are proposed that make it possible to reduce the parasitic recombination current down to less than 1% of the initial value. To suppress electron transport, an alternative structure based on three identical AlInAs barriers is also proposed. The GaAsP spacers separating these barriers from each other have different thicknesses. Due to this, its own set of quasi-bound (resonant) states is formed in each spacer that is different from the neighbor spacer set of states. As a result of this, the resonant tunneling channels are blocked: the parasitic electron flow is reduced by several tens of times in comparison with the case of spacers of equal thickness.

Coupling mechanism of materials and screen surface motion in multi-stage variable inclination equal thickness screening process

Multi-stage variable inclination equal-thickness screen (MSVIETS) is widely used in separating coal and mineral particles because of its large production capacity and good screening performance. In this study, the kinematic characteristics of infeed and outfeed ends surface under the conditions of load and no load was investigated by using a high-speed camera analysis system. The motion speed of the screen surface at the infeed end was approximately 5 times higher under load than under no-load conditions, and motion speed of the screen surface at the outfeed end was approximately 4 times higher than under no-load conditions. The mechanism of coupled motion of material and screen surface in the process of multi-stage variable inclination equal thickness screening was elucidated, and the energy coupling transfer law was “strong in and weak out”.

Experimental Study on Fire Risk Assessment of Windows by Material (II)

In this study, the fire safety standards for windows in Korea, the United States, and Japan were compared to prevent fire expansion through exterior wall openings. Experiments on polyvinyl chloride (PVC) and aluminum window frames widely used in Korea were performed. The tests were conducted according to KS F 2845, in which frames with equal thickness and area in a single-window form and 1 h fire-resistance glass with an 8 T thickness were combined. The experimental results showed that the PVC window was approximately 9 min, and the aluminum window was approximately 26 min. However, in Korea, there are no test standards for windows installed at the opening of exterior walls. In addition, fire safety standards for windows should be established along with designations of fire prevention zones.

Control of strain in subgrains of protein crystals by the introduction of grown-in dislocations

It is important to reveal the exact cause of poor diffractivity in protein crystals in order to determine the accurate structure of protein molecules. It is shown that there is a large amount of local strain in subgrains of glucose isomerase crystals even though the overall crystal quality is rather high, as shown by clear equal-thickness fringes in X-ray topography. Thus, a large stress is exerted on the subgrains of protein crystals, which could significantly lower the resistance of the crystals to radiation damage. It is also demonstrated that this local strain can be reduced through the introduction of dislocations in the crystal. This suggests that the introduction of dislocations in protein crystals can be effective in enhancing the crystal quality of subgrains of protein crystals. By exploiting this effect, the radiation damage in subgrains could be decreased, leading to the collection of X-ray diffraction data sets with high diffractivity.

Rendering of Newton’s Rings in Monochrome Light

Newton's rings are an interference pattern related to fringes of equal thickness. This image can be obtained on a simple experimental optical setup. Modern common renderers, based on zerothickness ray tracing, calculate highly realistic images of complex 3D scenes, which are computer models of scenes from the real world. However, they do not allow you to reproduce such phenomena as interference, because they ignore even the polarization of light. Interference is studied by physical optics, and it is natural to assume that if the calculation is based on the "tracing" of waves in the scene, this problem can be solved. An algorithm is known when a solid beam of light is used instead of a light wave. The results of the calculations show images of the interference effects; Newton's rings are also calculated. This is an acceptable solution for simple scenes involving a few objects. It is also good for optical design systems, when the result is important, and not the time spent. But not practical for universal renderers, which must calculate the image in an acceptable time for very complex scenes. In this paper, we propose an algorithm based on the traditional method of tracing paths consisting of zero-thickness rays. Only on the last ray of a path that crosses the picture plane is the modification made. It is assumed that these rays characterize spherical wavelets. In this paper, we consider the results of applying the mentioned heuristics to classical optical experiments.

Comparison of passive damping treatments based on constrained viscoelastic layers and multi-resonant piezoelectric networks.

This work aims at comparing the damping performances of two passive damping treatments based on piezoelectric or viscoelastic patches. The motivation for such a comparison stems from the fact that the two damping techniques have been developed fairly independently, and are rarely compared. First, the dynamic response of a simply-supported metallic plate is measured experimentally after being equipped with constrained viscoelastic patches or piezoelectric patches connected to an electrical network. In order to extend the comparison, a numerical model of the structure is set up and validated to evaluate the damping performances of both passive treatments under different configurations (for instance equal-mass and equal-thickness configurations). Finally, with regard to these experimental and numerical results, the advantages and the limitations in using viscoelastic or piezoelectric treatments are discussed.