Advanced Materials Research Vol. 740

Abstract: The objective of this research is to improve the performance of the read-write head process in Hard disk drive manufacturing with respect to Bit Error Rate (BER). With the preliminary survey, the process capability index (Cpk) of BER was 0.72 which is less than the one side acceptable value at 1.25. To improve Cpk of BER, five phases of Six sigma approach are applied starting from define, measure, analyze, improvement and control phases. At 95% confidence, thermal protrusion, writing current amplitude, writing current overshoot, number of defects on media and writing head width are the significant factors for Bit Error Rate due to their p-value less than 0.05. Since the number of defects and writing head width are uncontrollable factors, the experiment are designed and performed based of general factorial design with three levels of each controllable factor. At 5% significance level, there are the interaction effects between the thermal protrusion and the writing current amplitude as well as the interaction affects between the writing current amplitude and the writing current overshoot. With the general linear model (GLM), the suggested values for the thermal protrusion, writing current amplitude and writing current overshoot are 35 DAC, 10 mA and 9 mA, respectively. Under the suggested condition, Cpk of BER is increased from 0.72 to 2.38 and the percentage of defective due to head related failure is reduced from 21.85% to 9.86%.

Abstract: By improving the optical module internal thermal test platform for media and increase cooling efficiency, solve LASER_TCT/CCT OTU class plate temperature warning faults such as, and has been tested. Test results showed that the improvement to meet design requirements.

Abstract: With the shrinkage of the IC device dimension, Cu and ultra-low-k dielectric were introduced into IC devices to reduce the RC delay. Ultra-low-k dielectrics generally suffer more damage than silicon oxide dielectric during process integration and subsequently cause reliability degradation. Therefore, ultra-low-k damage characterization on Cu damascene structures is of great importance to understand the damage mechanisms. This paper describes the application of UV-Raman microscopy with enhanced spatial resolution and signal sensitivity for characterizing ultra-low-k dielectric in the three-dimension structure of Cu metallization with nanometer feature size. It shows UV-Raman technique has an advantage in analyzing ultra-low-k layer on patterned wafer and extracting ultra-low-k signals from Cu/ultra-low-k mixed structure. UV-Raman is also effective to characterize the ultra-low-k degradation for ultra-low-k related reliability analysis by time dependent dielectric breakdown (TDDB) test.

Abstract: Automated complex Gas Reaction Controller and its application for hydrogen storage materials investigation are described in this article. Pressure-composition isotherms (PCI) and kinetics measurements of LaNi₅ have been obtained for validation of the apparatus. Measurements of both absorption and desorption PCI curves and kinetics measurements at different conditions have been obtained for carbon nanotubes to estimate its hydrogen storage properties.

Abstract: When using monolithic hot die to forge the umbrella head of valve parts, hot die of a short life. Through the analysis of factors caused by mold, the structure design, mold material, mold manufacturing and use to take certain measures, the production practice showed that die fatigue crack generation and extended time to prolong service life, obviously improved.

Abstract: Thick laminated composites are manufactured commonly by vacuum bagging of fiber-resin mix or prepregs on a suitable mould and, subsequently curing the lay-up at high temperature and pressure in an either autoclave or oven. At these pressures and temperatures, excess resin bleeds out of the lay-up during the initial stages of the curing. The amount of resin bleed is also a function of the bleeder parameters. Bleeder is a porous fibrous media that is laid around stacked lay-up to provide pathway for volatiles as well as absorb and hold the excess resin. Thicker or highly porous bleeders generally absorb higher amount of resin resulting in a resin starved laminate whereas very thin or denser bleeder leads to resin-rich areas within the laminate. It is thus important to select optimum bleeder parameters in order to achieve a desired resin volume fraction and its uniformity in a composite laminate upon curing. This paper details the simulation of the manufacturing of a thick laminated composite, where a significant amount resin is likely to flow out of a curing lay-up, leading to an optimization of bleeder parameters. A coupled, transient FE analysis is conducted that involves not only the heat transfer, resin flow and cure reaction kinetics simulation but also the simulation of the compaction of the wet laminate and the bleeder layers until the laminate is fully cured. Details of an experiment conducted to find compression characteristics of bleeder of varying thickness and the number of layers and related data that was used in the FE analysis are discussed in this paper. It is found that bleeder thickness significantly affects the amount of resin bleeding out from the curing laminate. As a result, the resin volume fraction of the laminate is affected. Case studies carried out to highlight the optimum bleeder thickness for a lay-up, and the method used to decide the thickness and the number of bleeder layers, are presented.

Abstract: This research work investigates the surface degradation of modified surface as part of wind turbine blade surface which is made from epoxy resin mixed with calcium carbonate (CaCO₃) in different percentage as a filler elements. Accelerated test with AC voltage of 4.5 kV 50 Hz with a saline solution using flow rate of contaminant equals to 0.6 ml/min according to IEC 60587 standard [. It was found that ,the solid insulators which has a high percentage of calcium carbonate filler will slowdown the process of surface tracking. On the other hand, if the percentage of filler is more than 40% by weight ,it will lead to a faster tracking . In addition, researchers have tried to develop a type of surface condition by comparing the time to track between flatted and corrugated surfaces test sample. It was found that , the flatted surface can withstand the generated track than corrugated surface. Also, when the incline plane has been increased rather than 45 degrees, the breakdown process occurred slowly.

Abstract: Herschel-Bulkley model is used to describe the constitutive behavior of Magnetorheological (MR) fluids subject to an applied magnetic field. Based on the shear flow equation at the narrow gap, a theoretical analysis of the effect of the applied magnetic field on the viscoplastic flow between two parallel disks is presented. The expression for the velocity in viscoplastic flow is derived. The results indicate that the velocity profile of MR fluid in shear region is deeply dependent on the gradient of the pressure in the flow channel. For the negative pressure gradient value, the velocity peak value point tends to move toward the driven disc wall as absolute value of pressure gradient increases. However, the velocity peak value point tends to move toward the driving disc wall as absolute value of pressure gradient increases for the positive pressure gradient value.

Abstract: We investigated the optical characterization of luminescent thioglycolic acid (TGA) stabilized CdTe quantum dots (CdTe-QD) synthesized in water. The influence of stabilizing agents on the luminescent properties of water-soluble CdTe quantum dots (QDs) was described. It is found that QDs can be synthesized easily when TGA is chosen as stabilizing agent and TGA leads to preparation of highly luminescent QDs due to the secondary effects of bonds between Cd²⁺ and sulfhydryl groups. The absorption wavelength and PL stability of TGA-CdTe are also characterized. Size can be controlled between 2.0 nm to 4.0 nm. The TGA-CdTe QDs prepared at 2 h reaction time possess excellent luminescent properties.

Abstract: The increase in the structural damping ratio can make the degree of seismic response lower, while the damping ratio causes the seismic response differently in the different national specification. The paper first introduces the principle of equivalent damping ratio of the seismic response calculation methods in seismic specification of China and Japan, then analyzes and compares reduction of seismic response caused by the equivalent damping ratio in seismic specification of China and Japan by calculating data.