Advanced Materials Research Vol. 893

Abstract: The output characteristics of concentrator photovoltaic (CPV) system were analyzed in the data period of a year from November 2010 to October 2011. Characteristics of CPV are more sensitive to environmental factors as compared to flat-plate PV system. Especially, solar spectrum distribution has considerable influence on the output of CPV because CPV uses multi-junction solar cells. In this study, we analyzed the influence of environmental factors using average photon energy (APE) and temperature of solar cell (T_cell). Most frequent condition during operation was APE = 1.87 ± 0.005 eV and T_cell = 65 ± 2.5 °C. Performance ratio at the most frequent condition was 83.9%. These results indicated the importance of the understanding of the behavior of the outdoor performance and the accurate data of environmental conditions where the PV systems were installed.

Abstract: Green performance assessment of power battery is a whole life cycle process, which integrates Environment (E), Resource (R), Technology (T) and Cost (C) objectives considered as evaluation of multi-objective and multi-stage. According to definition of Green Product, the assessment model of multi-objective and multi-stage for power battery was built. The green utility function is proposed, by which the evaluation data of indices are changed uniformly into range of (0, 1) according to the assessment standard initialized as 0.5. The synthesis calculation method is given, which remains all the messages in the assessment. Finally, the green performance comparison between lithium-ion battery and nickel metal hydride battery proves the assessment method and process.

Abstract: This article discusses the physical theory and mathematical modeling of epsilon-negative (ENG) material. Numerical simulation results are also given in later part of this article, and they prove that this kind of material has a great shielding effect. We mainly focus on the modeling and simulation of one dimensional epsilon-negative (ENG) material. First we set up a Drude model to theoretically simulate ENG material, and then use the finite difference time-domain methods to analyze the electromagnetic wave propagation in our shielding material.

Abstract: In this study, the interactions between poly (ethylene oxide) (PEO) and lithium-montmorillonite (LiMMT) have been investigated using density functional theory (DFT) calculation. The results of calculations show that the adsorption process of PEO on the LiMMT surface is physisorption with adsorption energy of -0.063 eV. This observation is consistent with the results of our calculations on PES (Potential Energy Surface) and PEC (Potential Energy Curve). The formation of space between PEO and LiMMT are found in range of 3.4 - 4.2 Å which are in good agreement with experimental results.

Abstract: Multi-level-cell (MLC) operation of Cu-doped SiO_x-based (SiO_x:Cu-based) resistance random access memory (ReRAM) has been reported for the first time. For this study, we employed a novel ion bombardment-induced (IB-induced) SiO_x:Cu switching layer (SL). Using modulation of SET-current compliance, we completed 2-bit-per-cell memory application. The MLC resistance switching process is described in detail. Owing to controllability of Cu source from advanced IB technique, the IB-induced SiO_x:Cu SL shows good cell-to-cell uniformity of MLC resistance switching parameters, including operation voltages and resistance states. Additionally, the IB-induced TaN/SiO_x:Cu/TaN ReRAM exhibits infinite potential for MLC operation, such as over 3 times differentiation space among memory states, robust resistance retention, and promising operation endurance properties. During frequent MLC resistance switching, moreover, the IB-induced SiO_x:Cu-based device also has excellent single-cell uniformity of memory states due to IB-induced thin Cu filament.

Abstract: In this work, we are using Voltage Scaling as energy efficient technique to make energy efficient MBCCS. In MBCCS, whenever voltage or current of battery will under the threshold level the battery will continuing the charge if more than voltage or current threshold then battery will invoke Ring Overcharge Alarm. In Voltage Scaling, we scale down supply voltage from 1V to 0.1V, where 0.9V, 0.8V, 0.7V, 0.6V, 0.5V, 0.4V, 0.3V and 0.2V are intermediate supply voltage value. There is 92.72%, 87.50%, 98.77% and 68.24% reduction in Clock Power, Logic Power, Signal Power and IO Power on 1 THz device operating frequency when voltage is scale down from 1V to 0.1V with step size of 0.1V.

Abstract: The optical efficacy and reliability of light emitting diode is extensively influenced by the operating junction temperature of the LED. Therefore, the evaluation of junction temperature is significant. This paper reports a simulation analysis on the heat dissipation of single chip LED package with based material, copper diamond (Cu/Dia) cylindrical heat slug.Ansys version 11 was utilized as the simulation platform. The junction temperature and stress of the LED chip under natural convection condition were evaluated with varied input power of 0.1 W, 0.5 W and 1 W. Results indicated the maximum junction temperature of LED chip was attained at input power of 1 W.

Abstract: High power light emitting diodes are currently challenged by thermal issue of high heat generation which limits the reliability and efficiency. Each component in the LED package has a significant role in heat dissipation. In this paper, a simulation study was done to scrutinize the influence of heat slug shape on the heat dissipation of single chip LED package using Ansys version 11. Two types of heat slug shapes, rectangular and cylindrical were used. The analysis was carried out under natural convection condition at ambient temperature of 25°C. Simulated results indicate that rectangular shape heat slug exhibits better heat dissipation.

Abstract: The vast development of the LED industry has created contemporary set of thermal issues with limits the reliability of the high power LEDs. Thus, this paper reports a simulation analysis done on single chip high power LED package to evalute the effects of heat slug material on the heat dissipation of the LED package. The heat dissipation of two types of heat slug material, aluminum (Al) and copper (Cu) were compared in terms of junction temperature, von Mises stress and thermal resistance of the LED chip at varied input power of 0.1 W and 1W. Results of the analysis showed that the copper heat slug exhibits a better heat dissipation due to its superior thermal conductivity.

Abstract: Two quaternary ammonium tetraphenyl borates salt photobase generators were synthesized using 2-naphthoymethylene as chromophores, and triethylene diamine, pyridine. Their UV curing properties were studied in different environment. The results showed that their photolysis kinetics was of the first order reaction. Quaternary ammonium salts with the UV irradiation can initiate free radical photopolmerization and cure the epoxy resin.