Progress on Silicone Packaging Materials for Power LED

AbstractEncapsulation materials are very vital to the power light emitting diode packaging and become a hot topic for worldwide researchers because the devices packaging and assembly yield, and the devices reliability and lifespan are determined by the quality of packaging and assembly materials as well as their processing. In this paper, the functions requirements and properties of power LED packaging materials were introduced. In addition, the research progress on traditional LED packaging materials, especially high refractive index silicone encapsulants were discussed in detail. Meanwhile, the direction of further development of encapsulation materials was pointed out

Scanning Speed Effect on Mechanical Properties of Ti-6Al-4V Alloy Processed by Electron Beam Additive Manufacturing

AbstractIn this study, mechanical properties in Ti-6Al-4V samples built with the powder-bed electron beam additive manufacturing (EBAM) process over a range of beam scanning speeds were experimentally investigated. Four levels of speed functions were applied to build samples, which were used to prepare the specimens for the nanoindentation test to obtain their mechanical properties. The measured averaged Young's modulus and hardness are about 111.7∼119.0GPa and 5.24∼6.52GPa, respectively. It has been found that the Young's modulus and hardness increase with the increase of scanning speed in EBAM. The scanning surface presents more superior mechanical properties than those from side surface. The mechanical properties are also correlated to the microstructure characterization of EBAM components

Combined antioxidant formulation of ascorbic acid with resveratrol ameliorates isoproterenol-induced myocardial infarction in rats

The current investigation was proposed to assess the effectiveness of the combination of resveratrol and ascorbic acid against Isoproterenol (ISO)-induced myocardial infarction in rats. The experimental model was divided into six groups (n = 6 in each group). Group I: control, Group 2: isoproterenol (ISO)-100 mg/kg b.wt, Group 3: ISO+Resveratrol (RES) (20 mg/kg b.wt) treated, Group 4: ISO+ Ascorbic acid (AA) (80 mg/kg b.wt) treated, Group 5: ISO+RES (20 mg/kg b.wt)+AA (80 mg/kg b.wt) treated and Group 6: RES (20 mg/kg b.wt)+ AA (80 mg/kg b.wt) alone treated. The study showed an increase in lipid peroxides and cardiac markers in the serum samples of experimental animals administered with ISO. Treatment with RES and AA individually and a combinational formulation brought a significant decrease in lipid peroxides and cardiac markers. They increased the level of enzymatic antioxidants and non-enzymatic antioxidant levels. Histopathological results showed the distortion of heart architecture among the experimental groups administered with ISO and significant recovery when treated with RES and AA individually and in their combination. The study presents the effective combination of RES and AA in combating ISO-induced myocardial infarction and protection against ROS-mediated oxidative stress

Odor Characteristics and Formation Pathways of Low-Salted Large Yellow Croaker

In this study, our purpose was to investigate the effect of mild salting on the flavor of large yellow croaker. The volatile flavor compounds of raw (unsalted) and low-salted large yellow croaker were determined by solid phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) and evaluated by gas chromatography-olfactometry (GC-O) and odor activity values (OAV) analysis. The GC-MS analysis showed that the contents of hexanal, nonanal, heptanal, 1-octene-3-ol, anethole and hexanol in both samples were higher than those of other volatile compounds identified. GC-O and OAV analysis showed that the flavor of raw large yellow croaker was significantly affected by 1-octene-3-ol, octanal, nonanal, hexanal, heptanal, (E,Z)-2,6-nonadienal, trans-2-octenal and anethole (OAV > 1); the flavor of low-salted large yellow croaker was significantly affected by linalool, nonanal, hexanal, octanal, 1-octene-3-ol, anethole, (E,Z)-2,6-nonadienal and heptanal (OAV > 1). The changes in flavor after salting treatment was attributed to a significant increase in the OAV of linalool and anethole, and a significant decrease in the OAV of 1-octene-3-ol, hexanal, nonanal, trans-2-octenal, (E,Z)-2,6-nonadienal, heptanal and octanal. The changes of some flavor components might be related to reactions such as the oxidative degradation of unsaturated fatty acids, the biosynthesis of terpenoids, the isomerization of aromatic alcohols, the oxidation and reduction of aliphatic aldehyde and esterification

Grade Distribution Modeling within the Bauxite Seams of the Wachangping Mine, China, Using a Multi-Step Interpolation Algorithm

Mineral reserve estimation and mining design depend on a precise modeling of the mineralized deposit. A multi-step interpolation algorithm, including 1D biharmonic spline estimator for interpolating floor altitudes, 2D nearest neighbor, linear, natural neighbor, cubic, biharmonic spline, inverse distance weighted, simple kriging, and ordinary kriging interpolations for grade distribution on the two vertical sections at roadways, and 3D linear interpolation for grade distribution between sections, was proposed to build a 3D grade distribution model of the mineralized seam in a longwall mining panel with a U-shaped layout having two roadways at both sides. Compared to field data from exploratory boreholes, this multi-step interpolation using a natural neighbor method shows an optimal stability and a minimal difference between interpolation and field data. Using this method, the 97,576 m3 of bauxite, in which the mass fraction of Al2O3 (Wa) and the mass ratio of Al2O3 to SiO2 (Wa/s) are 61.68% and 27.72, respectively, was delimited from the 189,260 m3 mineralized deposit in the 1102 longwall mining panel in the Wachangping mine, Southwest China. The mean absolute errors, the root mean squared errors and the relative standard deviations of errors between interpolated data and exploratory grade data at six boreholes are 2.544, 2.674, and 32.37% of Wa; and 1.761, 1.974, and 67.37% of Wa/s, respectively. The proposed method can be used for characterizing the grade distribution in a mineralized seam between two roadways at both sides of a longwall mining panel

Defect Detection of SMT Electronic Modules

To automatically detect SMT (surface mount technology) electronic modules, algorithms are investigated for geometry and shape features, module matching and detection in PCB (printed-circuit board) components. First, geometry and shape features of SMT electronic modules are presented. Then matching technology and process for SMT electronic modules are studied through optimization searching algorithms, such as similarity based detection and pyramid algorithms. Based on the analysis of major defects, algorithms for detecting major defects in SMT electronic modules are investigated. Finally, the crucial factors affecting inspection precision and speed, i.e., components contour, searching range and minimum similarity, are analyzed. The experimental results show the detection time for Circuit Boards without defect is 0.82s, and for those with one component absent 0.89s, yet for multiple components absent 10.68s. Therefore, it can satisfy the requirements of high reliability, stability, precision, inspection speed and anti-interference for defect detection in SMT electronic module of Circuit Boards