In this paper, the heat distribution for single chip high power LED package attached with varied heat sink fin shapes were analyzed through simulation. The main focus of this study was to scrutinize the fluctuation of junction temperature with different shapes of heat sink fin designs. The simulation was done using Ansys version 11. The single chip LED was loaded with input power of 0.5 W and 1 W . Simulation was done at ambient temperature of 25°C under three convection coefficient of 5, 10 and 15 W/m 2.o C respectively. The obtained results showed that the LED package with pyramid pin fin heat sink has demonstrated a better thermal performance compared to the LED package with cylindrical pin fin heat sink.
Study on microfluid flow characteristic can be useful for most practical engineering application such as flows in inkjet printhead, drug delivery devices and microthermal technologies. Hence, in this paper, simulation of microfluid flow in Backward Facing Step (BFS) microchannel has been performed to visualize the flow characteristic at the step region. The microchannel used in this simulation has a step with a step height of 25% from the outlet height. The simulation has been carried out for various Reynolds numbers ranging from 0.1 to 500. The simulations result shows a recirculation zone is appeared at the edge of step for Reynolds numbers of 100, 300 and 500. Moreover, the radius of recirculation is increased further for the further increment of Reynolds numbers. Ansys CFX 11.0 software is used to perform the simulation.
This paper presents the design and optimisation of three types of high Quality (Q) factor air suspended inductors (symmetric (a), symmetric (b) and circular), using micro-electro-mechanical systems (MEMS) technology, for 10GHz to 20GHz frequency band. The geometrical parameters of inductor topology, such as outer diameter, the width of metal traces, the thickness of the metal and the air gap, are used as design variables and their effects on the Q-factor and inductance are thoroughly analysed. The inductor has been designed on high resistivity Silicon-on-Sapphire (SOS) substrate in order to reduce the substrate loss and improve the Q factor. Results indicate that the proposed inductor topology (symmetric (a)) has highest Q-factor with peak Q-factor of 192 at 12GHz for a 1.13nH inductance.
Reactive Ion Etching (RIE) is an important process in fabrication of semiconductor devices. Design Of Experiment (DOE) has been used to study the effect of Reactive Ion Etch (RIE) towards surface morphology of aluminum bond pad. Important RIE factors involved in this experimental study are ratio of Tetrafluoromethane (CF 4 ), Argon gas flow, BIAS, and ICP power. Different combinations of these factors produces different results of surface morphologies which was obtained using Atomic Force Microscopic (AFM). Produced results shows that overall surface roughness of the pad is affected by RIE and DOE offers a better way to optimize the desired outcome.
In this paper, the bondability of silicon bonded to different glass based material was studied by analyzing the bond strength comparison using the anodic bonding approach. The three types of glass based surface used were silica, pyrex, and soda lime glass. Experiments were carried out using an in-house designed anodic bonder and the bond strength were measured using a bond strength tester. Silicon will be placed on the positive terminal while the glass based materials will be placed on the negative terminal. The anodic process was done in two sets which are before and after the cleaning process for each sample. For every set, there are three different bonding partners, which are silicon with silica, silicon with Pyrex, and silicon with soda lime glass. From the results, it can be seen that majority of the samples showed higher bond strength after the cleaning process. Silicon bonded to soda lime glass showed the highest bond strength compared with other materials. This was followed by silicon to pyrex bonding and finally silicon to silica bonding. The maximum bond strength for all samples achieved in the range of 25 until 35 minutes of bonding time. After that, all samples show a critical decrease of bond strength except for the bonding process between silicon doped boron and silica. Cleaning process was proven a critical factor to achieve better bondability as shown in the higher bond strength obtained.
We demonstrate that the binding energy per nucleon of symmetric nuclear matter (SNM) (with Coulomb interaction switched off and N = Z) in the limit of zero density approaches to its value, uv, at the saturation density, where uv is the volume term of the Weizsacker mass formula. This phenomenon is a direct result of the clustering of nuclei in the low density region of nuclear matter. We study the implications of this result on the properties of nuclei. We also study the properties of asymmetric nuclear matter. Because of clustering a provocative interpretation of the equation of state of asymmetric nuclear matter emerges which is at considerable variance at low densities with hitherto all the previous calculations. For nuclei, as a framework, an extended version of Thomas-Fermi theory is invoked. Calculations are performed for 2149 nuclei with N, Z ≥ 8. The present scheme leads to a forceful interpretation of the low density asymmetry energy data of Natowitz et al. [1].
The reliability performance and structural of the solder joint on the Ball Grid Array (BGA) has become an important concern, due to increasing demand of electronic devices. The reliability of the BGA are evaluated through shear test. Different parameters of the ball shear test will cause the change on stress and strain. In this paper, a simple shear test on a single solder ball joints on Ball Grid Array (BGA) with varied shear speed was simulated. Lead free solder Sn-3.5Ag-0.7Cu is used in this analysis. Simple Single Factor (SSF) experiment for a single factor was used to analyse the load effect on a single solder ball. Simulation of load effects on BGA was accomplished by using ANSYS Version 11. The results in load effect on the single solder joint of BGA was plotted. Result shows that the high shear speed test obtains greater shear forces compare to low shear speed test.
Barium strontium titanate(Ba x Sr 1-x TiO 3 ), BST thin film was a ferroelectric material used commercially in worldwide since decades ago. Many researches were done on this BST thin film. In this work, the experiment is focus on the dielectric properties of Ba 0.7 Sr 0.3 TiO 3 thin film with different deposition layer. As the deposition layer of Ba 0.7 Sr 0.3 TiO 3 increase, the dielectric properties of the thin film increase.
High power LED are captivating attention due to its cogent impacts on lighting industry in terms of efficacy, low power consumption, long lifetime and miniature physical size. Nonetheless, the efficiency and reliability of the LED is signified by the junction temperature. This work demonstrates the thermal and stress simulation of single chip LED package with 1mm x1mm x 1mm copper heat slug. The simulation was performed using Ansys version 11. The GaN LED chip was powered with input power of 0.1 W and 1 W. The simulation outcome exhibited that at the maximum junction temperature and stress of the LED chip were 115.81°C and 221.56MPa correspondingly for input power of 1W.
Ball Grid Array (BGA) is a type of semiconductor interconnection used in Integrated Circuit (IC) which is being scaled down to micro and nanosize. The reliability of BGA in IC becomes a concern as the size of IC reduces. Hence, this leads to the study of stress on the BGA. This paper discussed the load effects of varying shear speed analysis on the BGA. A Pb-free material, Sn-3.9Ag-0.6Cu solder was applied in the simulation. Shear height value is fixed while the shear speed is varied to investigate the dynamic stress on a BGA package using Ansys software. The results from the graph plotted showed that higher shear speed results to higher shear force.
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