Numerical Modal Analyses of Beam-Supported Plates with Varying Thicknesses

In this study, numerical modal analyses are conducted on steel plates supported with various numbers of transverse beams. Natural frequency and mode shapes are obtained for each model. The same analyses are also repeated for plates with various thicknesses. Finally, the correlation between the number of supporting beams and natural frequencies is examined. The change in natural frequencies with respect to plate thickness is emphasized. In addition, general surface regression formulas of flexural natural frequencies with respect to the number of supporting beams and plate thicknesses are obtained.

General surface grafting strategy-derived carbon-modified graphitic carbon nitride with largely enhanced visible light photocatalytic H2 evolution coupled with benzyl alcohol oxidation

A general surface grafting strategy followed by in situ carbonization was developed to prepare the carbon-modified g-C3N4 with robustly enhanced visible light photocatalytic activity for H2 evolution coupled with benzyl alcohol oxidation.

Effect of mechanical treatment type on the strength of undoped single crystal indium antimonide wafers

Thin (100) wafers of single crystal undoped InSb have been strength tested by plane transverse bending. The strength of the wafers (≤ 800 mm in thickness) has been shown to depend on their mechanical treatment type. If the full mechanical treatment cycle is used (grinding + chemical polishing) the strength of the InSb wafers increases twofold (from 3.0 to 6.4 kg/mm2). We show that the strength dependence on mechanical treatment type for (100) wafers is similar to that for (111) wafers, the strength of (111) wafers being 2 times higher. The roughness of the thin wafers after the full mechanical treatment cycle has been measured using contact profilometry. After the full mechanical treatment cycle the roughness of the InSb wafers Ra decreases from 0.6 to 0.04 mm leading to general surface smoothening. We have compared the strength and roughness between (100) InSb and GaAs wafers. The roughness of InSb and GaAs wafers after the full mechanical treatment cycle decreases significantly: by 10 times for InSb due to the general surface smoothening and by 3 times for GaAs (Rz from 2.4 to 0.8 mm) due to a reduction of the peak roughness component. The full mechanical treatment cycle increases the strength of InSb wafers by removing damaged layers through the sequence of operations and reducing the risk of mechanical damage development.

Application of 3D CAD in the Design of Inspection and Planning System of Intelligent Three-coordinate Measuring Machine

Computer aided inspection planning based on CAD coordinate measuring machine is the basic key technology, which occupies a very important position in the quality system. Nowadays, the research of integration technology has made a lot of achievements, but the research on information integration of system and system lags far behind the information integration of machining. How to use the part information and measurement-related knowledge provided by the product model to automatically generate optimal testing procedures and testing instructions for use is the basic task of the oriented intelligent system. This paper aims at the development of intelligent CMM inspection planning system based on 3D, from the overall analysis and design of the system to the extraction of detection geometric information, sampling planning, detection path planning and automatic generation of quack measurement program and other related key technologies will be studied. This paper briefly analyzes the relevant factors that determine the number of sampling points and summarizes the point requirements for the distribution of sampling points, and in view of the shortcomings and limitations of various methods of sampling point distribution on the general surface, a sampling strategy with adaptive step size is proposed, which solves the problem of sampling planning on the general surface. In the specific implementation of sampling planning, it is divided into two ways: edge-based and face-based geometric element measurement and sampling. Considering the requirements of distribution points, specific sampling algorithms are designed respectively, focusing on the analysis of the differences between edges and faces.

Construction of Local Shape Adjustable Surfaces Using Quintic Trigonometric Bézier Curve

Based on quintic trigonometric Bézier like basis functions, the biquintic Bézier surfaces are modeled with four shape parameters that not only possess the key properties of the traditional Bézier surface but also have exceptional shape adjustment. In order to construct Bézier like curves with shape parameters, we present a class of quintic trigonometric Bézier like basis functions, which is an extension of a traditional Bernstein basis. Then, according to these basis functions, we construct three different types of shape adjustable surfaces such as general surface, swept surface and swung surface. In addition to the application of the proposed method, we also discuss the shape adjustment of surfaces showing with curvature nephogram (with and without fixing the boundaries). However, the modeling examples shows that the suggested approach is efficient and easy to implement.

Evaluation of Genomic DNA Extraction Using Monolayer and Bilayer Magnetic Nanoparticles

Background: There are different methods for genomic DNA extraction. Magnetic nanoparticles (MNPs) exhibit many important features making them suitable for DNA extraction. Objectives: The aim of this study was to compare the effect of monolayer and bilayer MNPs on genomic DNA extraction. Materials and Methods: The genomic DNA was extracted from the Staphylococcus aureus strain ATCC 25923 and clinical isolates using monolayer MNPs SiO2 and Fe3O4 and bilayer MNPs SiO2/Fe3O4. Then, the quality and quantity of the obtained genomic DNA were compared with both NPs. Results: The obtained results showed the concentration and purity of the extracted genomic DNA using bilayer magnetic NPs was significantly higher in comparison to the extracted genomic DNA by monolayer MNPs. Conclusion: In general, surface-coated MNPs are much more efficient than naked MNPs for genomic DNA extraction.