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Kornain Z.,University of Kuala Lumpur | Kornain Z.,Institute of Microengineering and Nanoelectronics IMEN | Jalar A.,Institute of Microengineering and Nanoelectronics IMEN | Rasid R.,National University of Malaysia | And 2 more authors.
Key Engineering Materials | Year: 2011

This paper presents the method to estimate curing profile's parameters for curing process of Moisture Resistance Cyanate Ester (MRCE) based underfill used in Flip Chip Ceramic Ball Grid Array (FC-CBGA). The two steps curing profile was found to eliminate voids formation in underfill during curing process. The important parameters in two steps curing profile such as first fixed temperature and duration of second temperature rise were estimated by superimposed of cure initiation curve and weight percentage loss curve of underfill epoxy material. Differential Scanning Calorimeter (DSC) analysis was carried out to characterize the cure kinetics reaction of underfill epoxy and produced the cure initiation curve. Thermal Gravimetric Analysis (TGA) was performed to characterize the weight loss of underfill and produced the weight loss curve. It was estimated that the first fixed temperature and duration of second temperature rise for two steps curing profile were 100 oC and 60-80 minutes respectively. The simulation experiment was conducted to verify the profile and no voids formation observed along this curing process. Source


Chong S.K.,University of Malaya | Goh B.T.,University of Malaya | Aspanut Z.,University of Malaya | Muhamad M.R.,University of Malaya | And 2 more authors.
Thin Solid Films | Year: 2011

Silicon nanowires (SiNWs) were synthesized by simultaneous evaporation of Au and Si deposition using H2 diluted SiH4. The deposition techniques combined hot-wire (HW) and plasma enhanced chemical vapor deposition (PECVD). Au wires were placed on the filament and heated simultaneously with the activation of the rf plasma for the dissociation of SiH4 and H2 gases. Five set of samples were deposited on ITO-coated glass substrate at different rf power varied from 20 to 100 W in an interval of 20 W, keeping other deposition parameters constant. High yield of SiNWs with diameter ranging from 60 to 400 nm and length about 10 μm were grown at rf power of 80 W (power density ∼ 1018 mW cm-2). Rf power of 100 W (power density ∼ 1273 mW cm-2) suppressed the growth of these SiNWs. The growth mechanisms of SiNWs are tentatively proposed. The nanocrystalline structure of SiNWs is confirmed by Raman spectra and HRTEM measurement. © 2011 Elsevier B.V. All rights reserved. Source


Aghigh A.,Multimedia University | Alizadeh V.,Multimedia University | Wong H.Y.,Multimedia University | Islam M.S.,Institute of Microengineering and Nanoelectronics IMEN | And 3 more authors.
Desalination | Year: 2015

Water as a basic necessity is an influential factor in our everyday lives but water pollution, urbanization, and huge population growth has led humankind to the brink of water resource scarcity. To address this issue, water filtration as well as desalination got enormous interest by the research community. Recently graphene, a new two dimensional material with exceptional capabilities and characteristics, has become apposite in the field of water filtration and desalination. This paper reviews the recent progress in Graphene research for water desalination using novel methods such as Nanoporous Graphene (NG) sheets as well as Capacitive Deionization (CDI) method. Among which most promising uniform NG sheets can be used for water filtration and desalination at a removal efficiency of 33-100% depending on the pore size as well as the applied pressure [1] and has a water flow rate of 10-100L/cm2/day/MPa [1] and by adjusting the pore size, different mineral filtrations can take place [1]. The main drawback which limits the widespread utilization of NG is the mechanical stability of NG sheets as the pore number increases since water permeability is directly proportional to the number of pores, pore distribution as well as the mass production of graphene sheets which has not been solved [1,2]. Apart from this, in CDI method, filtration is done by applying a certain potential difference between arrays of paired electrodes. The mentioned CDI method has moderate removal efficiency but has higher energy efficiency compared to the reverse osmosis method due to minimal energy requirement of only 0.1-2.03kWh/m3 [3]. Graphene oxide based desalination is another emerging desalination method which is gaining popularity because of its ease of fabrication, industry scale production, and strong mechanical stability [4,5]. It uses the "ion sponging" effect and can block hydrated ions with a radius greater than 4.5A°. But still this method should be further improved as small seawater salts are able to pass from the GO sieve [6,7]. © 2015. Source


Al-Qazzaz N.A.,National University of Malaysia | Al-Qazzaz N.A.,University of Baghdad | Ali S.H.,National University of Malaysia | Ahmad S.A.,University Putra Malaysia | Islam S.,Institute of Microengineering and Nanoelectronics IMEN
Neuropsychiatric Disease and Treatment | Year: 2014

The early detection of poststroke dementia (PSD) is important for medical practitioners to customize patient treatment programs based on cognitive consequences and disease severity progression. The aim is to diagnose and detect brain degenerative disorders as early as possible to help stroke survivors obtain early treatment benefits before significant mental impairment occurs. Neuropsychological assessments are widely used to assess cognitive decline following a stroke diagnosis. This study reviews the function of the available neuropsycho-logical assessments in the early detection of PSD, particularly vascular dementia (VaD). The review starts from cognitive impairment and dementia prevalence, followed by PSD types and the cognitive spectrum. Finally, the most usable neuropsychological assessments to detect VaD were identified. This study was performed through a PubMed and ScienceDirect database search spanning the last 10 years with the following keywords: “post-stroke”; “dementia”; “neuro-psychological”; and “assessments”. This study focuses on assessing VaD patients on the basis of their stroke risk factors and cognitive function within the first 3 months after stroke onset. The search strategy yielded 535 articles. After application of inclusion and exclusion criteria, only five articles were considered. A manual search was performed and yielded 14 articles. Twelve articles were included in the study design and seven articles were associated with early dementia detection. This review may provide a means to identify the role of neuropsychological assessments as early PSD detection tests. © 2014 Al-Qazzaz et al. Source


Wan Yusoff W.Y.,National Defence University of Malaysia | Jalar A.,Institute of Microengineering and Nanoelectronics IMEN | Othman N.K.,National University of Malaysia | Rahman I.A.,National University of Malaysia
Materials Science Forum | Year: 2016

The effect of high temperature storage of gold ball bonds towards micromechanical properties has been investigated. Gold wire from thermosonic wire bonding exposed to high temperature storage at 150 °C for 10, 100 and 1000 hours. The nanoindentation test was used in order to evaluate the high temperature storage effect on wire bonding in more details and localized. Prior to nanoindentation test, the specimens were cross-sectioned diagonally. The constant load nanoindentation was performed at the center of gold ball bond to investigate the hardness and reduced modulus. The load-depth curve of nanoindentation for the high temperature storage gold wire has apparent the discontinuity during loading compared to as-received gold wire. The hardness value increased after subjected to high temperature storage. However, the hardness decreased when the storage period is extended. The decreasing in the hardness value may due to the grain size of Au metal which recrystallized after subjected to high temperature storage. The results obtained from nanoindentation is important in assessing the high temperature storage of wire bonding. © 2016 Trans Tech Publications, Switzerland. Source

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