120 results on '"G, Carini"'
Search Results
2. Radiation effects induced by the energetic protons in 8x8x32 mm3 CdZnTe detectors
- Author
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A. Bolotnikov, G. Carini, M. Chekhlov, A. Dellapenna, J. Fried, J. Haupt, S. Herrmann, I. Kotov, D. Medvedev, A. Moiseev, G. Pinaroli, A. Rusek, M. Sasaki, M. Sivertz, L. Smith, and E. Yates
- Subjects
Nuclear and High Energy Physics ,Instrumentation - Published
- 2022
3. Technical Program
- Author
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G Carini, Antonio Benfante, and A Tomada
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Materials science ,Graphene ,Graphene foam ,X-ray detector ,Oxide ,Diamond ,Nanotechnology ,engineering.material ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,engineering ,Graphene nanoribbons ,Graphene oxide paper - Published
- 2015
4. Analysis of DNA from fingernail samples in criminal cases
- Author
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M.I. Ortiz, L. Laborde, A. Colussi, W.R. Bozzo, J.P. Pilili, G. Carini, and M. Lojo
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medicine.medical_specialty ,Genetics ,medicine ,Context (language use) ,Biology ,Dermatology ,Pathology and Forensic Medicine - Abstract
The detection of foreign DNA from the fingernail hyponychium may be relevant in the investigation of certain criminal acts, providing evidence of any sort of contact between the victim and the suspect. In this report, we analyzed results obtained from 164 fingernail samples collected by three different methods: extraction, clipping and swabbing. Samples were taken, mostly during the autopsy operation, and submitted to our Lab in the context of 71 different criminal cases. In 74.6% of the reviewed cases, a reportable DNA profile which matched the victims was recovered. In 13.2% of these profiles, foreign DNA was also detected as a minor contributor, representing almost a 10% of the analyzed cases. The estimated prevalence of foreign DNA samples beneath fingernails is comparable with that reported from volunteer donors screenings.
- Published
- 2015
5. DNA recovery of a gallstone in an action for damages
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W.R. Bozzo, M. Lojo, D.J. Mirson, G. Carini, and J.P. Pilili
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medicine.anatomical_structure ,DNA profiling ,business.industry ,Gallbladder ,Genetics ,Medicine ,Physiology ,Context (language use) ,Dna recovery ,business ,Pathology and Forensic Medicine ,Genetic profile - Abstract
In the context of a civil action for medical mala praxis a dry gallstone, a gallstone immersed in formalin and a gallbladder in the same preservative were submitted to our lab in order to analyze the identity of the donor. A blood sample of the victim was sent as reference. The dry gallstone showed the appearance of an irregular dark brown stone. Chemical analysis revealed that it was composed mainly of cholesterol. No DNA profiles were recovered from the samples immersed in formalin whereas the dry gallstone rendered a full DNA profile only from samples collected by surface scraping. A female genetic profile that did not match the victim was obtained. Although a gallstone is an unusual sample source, in this case the DNA analysis provided important evidence in solving the dispute.
- Published
- 2015
6. Characterization of the ePix10k camera at SSRL and LCLS
- Author
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P. A. Hart, G. Blaj, P. Caragiulo, G. Carini, A. Dragone, G. Haller, J. Hasi, R. Herbst, S. Herrmann, C. Kenney, H. Lemke, B. Markovic, S. Nelson, K. Nishimura, S. Osier, J. Pines, B. Reese, J. Segal, A. Tomada, M. Weaver, and D. Zhu
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Physics ,Optics ,business.industry ,Pixel array ,Detector ,Optoelectronics ,Synchrotron radiation ,Photonics ,business ,Linear particle accelerator ,Characterization (materials science) - Abstract
The ePix10k x-ray camera is under development at SLAC for use in hard x-ray experiments at the Linac Coherent Light Source (LCLS). It is a lower-noise, higher-maximum-signal autoranging replacement for the Cornell-SLAC Pixel Array Detector in wide-dynamic-range applications. A series of measurements to characterize a prototype system has been carried out at the Stanford Synchrotron Radiation Lightsource and LCLS. Results are presented here.
- Published
- 2014
7. Thermal and vibrational properties of silica xerogels
- Author
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A. Fontana, F. Rossi, G. Carini, G. D'
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General Chemical Engineering ,General Physics and Astronomy - Published
- 1998
8. Analysis of the low-temperature specific heat in polyethylene
- Author
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G. Carini, G. D'Angelo, G. Tripodo, A.
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General Chemical Engineering ,General Physics and Astronomy - Published
- 1998
9. Specific heats of rare-earth ions in crystalline and glassy phosphate matrices
- Author
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G. Carini, G. D'Angelo, G. Tripodo, A.
- Subjects
General Chemical Engineering ,General Physics and Astronomy - Published
- 1998
10. Why many polymers are so fragile: A new perspective
- Author
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C. Dalle-Ferrier, A. Kisliuk, L. Hong, G. Carini, G. D’Angelo, C. Alba-Simionesco, V. N. Novikov, and A. P. Sokolov
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chemistry.chemical_classification ,Length scale ,Chemistry ,Ergodicity ,Configuration entropy ,Relaxation (NMR) ,Complex system ,General Physics and Astronomy ,02 engineering and technology ,Polymer ,Polymers, Thermal properties ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Condensed Matter::Soft Condensed Matter ,Fragility ,Chemical physics ,Polymer chemistry ,Ergodic theory ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Many polymers exhibit much steeper temperature dependence of their structural relaxation time (higher fragility) than liquids of small molecules, and the mechanism of this unusually high fragility in polymers remains a puzzle. To reveal additional hints for understanding the underlying mechanism, we analyzed correlation of many properties of polymers to their fragility on example of model polymer polystyrene with various molecular weights (MWs). We demonstrate that these correlations work for short chains (oligomers), but fail progressively with increase in MW. Our surprising discovery is that the steepness of the temperature dependence (fragility) of the viscosity that is determined by chain relaxation follows the correlations at all molecular weights. These results suggest that the molecular level relaxation still follows the behavior usual for small molecules even in polymers, and its fragility (chain fragility) falls in the range usual for molecular liquids. It is the segmental relaxation that has this unusually high fragility. We speculate that many polymers cannot reach an ergodic state on the time scale of segmental dynamics due to chain connectivity and rigidity. This leads to sharper decrease in accessible configurational entropy upon cooling and results in steeper temperature dependence of segmental relaxation. The proposed scenario provides a new important insight into the specifics of polymer dynamics: the role of ergodicity time and length scale. At the end, we suggest that a similar scenario can be applicable also to other molecular systems with slow intra-molecular degrees of freedom and to chemically complex systems where the time scale of chemical fluctuations can be longer than the time scale of structural relaxation.
- Published
- 2016
11. Education and imaging. Hepatobiliary and pancreatic: Caroli's disease
- Author
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R, Pezzilli, G, Carini, and V, Cennamo
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Adult ,Cholangiopancreatography, Endoscopic Retrograde ,Male ,Sphincterotomy, Endoscopic ,Bile Ducts, Intrahepatic ,Treatment Outcome ,Pancreatitis ,Acute Disease ,Humans ,Tomography, X-Ray Computed ,Caroli Disease ,Cholangiography - Published
- 2009
12. Failure Investigation of the H301 Tubes For Thermal Cracker Heater
- Author
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Mohd bin Harun, Hafizal Yazid, Zaiton Selamat, Mohd Shariff Sattar, Muhamad Jalil, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
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Materials science ,Metallurgy ,Oxide ,Fraction (chemistry) ,Microstructure ,Metal ,Cracking ,chemistry.chemical_compound ,chemistry ,visual_art ,Thermal ,visual_art.visual_art_medium ,Tube (fluid conveyance) ,Composite material ,Layer (electronics) - Abstract
H‐301 tubes for thermal cracking heater were subjected to metallurgical analysis on 2nd October 2007. Results of this analysis indicate that these tubes are of ASTM A355P5 specification. A hard oxide layer formed on the outer surface that is exposed to high temperature and the hardness value on this surface was 250 HB30. The hardness value of other part of the metal was 128.5 HB30. The inner surface was deposited with by‐product of cracking process. The tube expanded in the direction of tube axis causing a little bend to this tube. The change in metal thickness was considered insignificant. Difference in hardness between exposed and new tube was only 10 HB30, which means that the difference in mechanical properties between these tubes were very small. According to the class of damage, the microstructure is still in the class between C and D. This means that only 2.5%—10% of life fraction the material has been consumed. Thus, the remaining life of the tube is about 90%. Based on these results, the tube still may be used for another 10 to 15 years if operating temperatures are in the recommended ranges (400–550°C).
- Published
- 2008
13. Characterization of Soils Using Microwave Radiation
- Author
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M. F. A. Aziz, M. S. Jaafar, H. B. Senin, S. A. Hashim, G. Carini, J. B. Abdullah, and D. A. Bradley
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Junction diodes ,Loam ,Soil water ,Soil science ,Soil type ,Geology ,Microwave ,Gunn diode - Abstract
The aim of this study is to characterize of soils using microwave radiation by the reflection techniques. The sample of soils was collected in Northern Peninsular of Malaysia. There are six types of soil have been indentified, which, sand, clay, loam, silty clay loam, silty loam and clay loam. We use the transmission of microwave using Gunn Diode Transmitter with frequency of 10.525 GHz and the pipette method. The result shows that, the soil type can be indentified using intensity values based on the percentages of the clay. The proposed technique also can be used to characterize soils using by microwave radiation.
- Published
- 2008
14. Nuclear Power: Is It a New Clear Choice for Malaysia
- Author
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Idris B. Besar, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
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Consumption (economics) ,Economic growth ,Industrialisation ,business.industry ,Development economics ,Sustainability ,Per capita ,Economics ,Nuclear power ,Standard of living ,business ,Environmental degradation ,Energy policy - Abstract
Energy is essential for socio‐economic development. Any nation's standard of living is closely related to its access to energy. To put into perspective, the per capita electricity consumptions in developed countries of the Organisation for Economic Cooperation and Development (OECD) is currently estimated at 8600 kilowatts‐hour per year as compared to the consumption rates in Malaysia and some African countries of 3300 and 50 kilowatts‐hour per year, respectively. Energy is therefore an important pre‐requisite for achieving the Malaysian vision of becoming a developed nation by the year 2020, in that it is needed not only for industrialization programme but also in maintaining quality of life. In Malaysia, the main concern currently is still on the supply in term of adequacy, reliability and quality; and moving slowly but steadily towards security, sustainability, environmentally friendly and contribution to climate change. With this new dimension, nuclear power emerged as a good match to a possible alternative in the comprehensive national energy policy. Many studies presented the positive aspects of nuclear power while others indicated the bad sides and potential risks. This paper will highlight some of those pros and cons as well as the potential risks beside a discussion on relevant requirements for a nuclear power programme in particular those of interest to the professionals in the physical sciences.
- Published
- 2008
15. An Experimental Study of Defect Determination using Pulsed Thermal Non-Destructive Testing
- Author
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M. Z. Umar, I. Ahmad, A. R. Hamzah, W. S. W. Abdullah, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
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Materials science ,business.industry ,Nuclear engineering ,Nondestructive testing ,Thermal ,Thermography ,Structural engineering ,business - Abstract
The application of Infrared Thermography (IRT) as passive method is widely used and accepted by industry. However, IRT technology as transient or active method is considerably new for industry in term of measuring defect in Non‐Destructive Testing (NDT) activities. The primary objective of this paper is to present an experimental study of determination of artificial defect in material using active thermography, in particular to pulsed thermal NDT (TNDT). Both terminology and basic principles in TNDT will be discussed. It is shown that several factors may influences TNDT results. As a conclusion, this study has confirmed the ability and potential of TNDT as a technique for defect determination in material.
- Published
- 2008
16. Corrosion Inhibition of Sodium Benzoate on Aluminum Alloys in Tropical Seawater
- Author
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R. Rosliza, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
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Materials science ,Metallurgy ,technology, industry, and agriculture ,chemistry.chemical_element ,equipment and supplies ,Corrosion ,Metal ,chemistry.chemical_compound ,Adsorption ,chemistry ,Pulmonary surfactant ,Aluminium ,visual_art ,Sodium benzoate ,visual_art.visual_art_medium ,Seawater ,Anaerobic corrosion - Abstract
The corrosion inhibition of aluminum and its alloys is the subject of remarkable technological importance due to their increased industrial applications. This paper reports the results of the corrosion inhibition properties of AA6061 and AA6063 aluminum alloys in tropical seawater using sodium benzoate as an inhibitor. It was found that the corrosion inhibition occurred through the adsorption on the surfactant on the metal surface without modifying the mechanism of corrosion processes.
- Published
- 2008
17. Catalytic and Physical Properties Study on NiO and Pr[sub 2]O[sub 3]-NiO Based Catalyst for CO[sub 2]∕H[sub 2] Methanation
- Author
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R. M. Hasmizam, H. B. Senin, B. N. Aziah, W. A. B. W. Azelee, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Materials science ,Chemical engineering ,Methanation ,Specific surface area ,Nickel oxide ,Doping ,Non-blocking I/O ,Particle size ,Catalysis ,Amorphous solid - Abstract
The catalytic behaviour of undoped NiO and doped Pr2O3‐NiO catalysts toward CO2/H2 methanation reaction has been performed. The result showed 100% conversion of CO2 to CH4 in the presence of H2 for doped 60Ni‐40Pr at 300 °C, while for undoped NiO, there was only 40% of CO2/H2 methanation at the same temperature. The result corresponds to the presence of higher specific surface area of 60Ni‐40Pr compared to undoped NiO catalyst. The XRD analysis showed that this catalyst has some degree of amorphous properties and the existence of individual phases of cubic NiO and cubic Pr2O3, which serves more active site for CO2/H2 methanation. In addition, complimentary results obtained from SEM showed the present of homogeneous smaller particle size, which support the good performance of 60Ni‐40Pr catalyst towards CO2/H2 methanation.
- Published
- 2008
18. Energy Band Crossing Points in Multilayers of Graphene
- Author
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Noriza Ahmad Zabidi, Hasan Abu Kassim, Keshav N. Shrivastava, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
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Materials science ,Condensed matter physics ,Graphene ,law ,Band gap ,Monolayer ,Stacking ,Hexagonal lattice ,Graphite ,Electronic band structure ,Layer (electronics) ,law.invention - Abstract
The monolayer of carbon atoms in a hexagonal lattice is called graphene. It is a monoatomic layer of graphite. The stacking of hexagons one over the other creates a variety of layers. We can stack in such a way that the hexagons of the first layer coincide with the hexagons of the next layer or they may be displaced. In this way we are able to make three types of layer stacks of graphene. These are called A, B and C types. We have found that a single layer of graphene shows a small gap of 27.212 meV. In the two layers of the AA type also the crossing is avoided. The energy from the apparent crossing point towards higher energies is not equal to that towards lower energies. The energy levels are not symmetric with respect to the apparent crossing point. In the AB type stacking for two layers the energy gap is 4.8 meV. The energy gap for a variety of stacking of layers has been obtained from the non‐relativistic Schrodinger theory.
- Published
- 2008
19. The Effects Of Slanted Mesa Sidewall On P-N Junction GaN-Based LEDs
- Author
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M. F. Othman, A. Abdul Aziz, M. R. Hashim, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
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Materials science ,business.industry ,Substrate (electronics) ,Edge (geometry) ,Cathode ,Anode ,law.invention ,Optics ,law ,Etching (microfabrication) ,Sapphire ,Optoelectronics ,business ,p–n junction ,Light-emitting diode - Abstract
Typically, most of the commercially available GaN‐based LEDs (Light Emitting Diodes) are grown on sapphire as their substrates. Due to the insulating substrate, lateral current injection is employed so that the anode and cathode contacts are in side‐by‐side configuration. During the etching process, the possibility of slanted mesa sidewall to form is higher. In this work, the influence of slanted mesa sidewall are studied while its light emitting area size and contacts position are maintained. The comparison for optical output power, current‐voltage, thermal dissipation and distribution characteristics of different angles of slanted mesa sidewall are performed. Angles of slanted mesa sidewall are varied from angle‐in and angle‐out with reference to 90° at mesa edge. The simulation results revealed that with the increment of slanted angle, the LEDs performed better due to improved overall emission intensity and uniform current distribution of the devices. The angled sidewalls efficiently deflect photons that are initially guided laterally within the GaN epilayer in the off‐surface direction. As such, devices showed better overall performance.
- Published
- 2008
20. The Effective Energy in Nuclear Reactions from Exact Probability by Using the WKB Approximation
- Author
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Azni Abdul Aziz, Norhasliza Yusof, Hasan Abu Kassim, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
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Physics ,Reaction rate ,Nuclear reaction ,Nonlinear system ,Double beta decay ,Quantum mechanics ,Quantum electrodynamics ,Coulomb barrier ,Transmission coefficient ,Nuclear Experiment ,WKB approximation ,Quantum tunnelling - Abstract
The transmission coefficient through a Coulomb barrier in nuclear reaction is obtained by using the WKB approximation. Hence, we can determine the exact tunneling probability from this method. This probability can be applied in calculating the astrophysical thermonuclear reaction rates. One of the most important aspects in calculating the reaction rates is the value of the most effective energy, E0 for the reaction to occur. The Gamow peak produces a nonlinear equation that is solved iteratively to produce E0.
- Published
- 2008
21. Retrieving Sea Surface Temperature Using NOAA APT Data In Sabah Coastal Region
- Author
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Mohammad Syahmi Nordin, Fauziah Abdul Aziz, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
High-resolution picture transmission ,Automatic picture transmission ,Sea surface temperature ,Radiometer ,Geography ,Meteorology ,Advanced very-high-resolution radiometer ,law ,Radiance ,Radiosonde ,Satellite ,law.invention ,Remote sensing - Abstract
The sea surface temperature, SST of Sabah coastal area under clear sky conditions was investigated. Automatic Picture Transmission, APT thermal infrared data from National Oceanic Atmospheric Administration, NOAA satellite of Advanced Very High Resolution Radiometer, AVHRR was used. The APT data was obtained in real-time mode at Ground Receiving Station, GRS in Universiti Malaysia Sabah, UMS. An image processing approach and Planck distribution function method were used to convert the grey-level digital numbers of the APT imagery into radiance values. These data were then converted to 10-bit digital number data of High Resolution Picture Transmission, HRPT images for calibration purposes. Geometric correction was applied with ground control point for APT data. A single channel method together with radiosonde data has been used for the atmospheric and emissivity corrections. The satellite sensor SST was compared with in-situ measurements taken from ships at sea. The results from the SST obtained from APT data give 2.6 degrees C to 2.7 degrees C lower than in-situ data.
- Published
- 2008
22. Chitosan Based Film Electrolytes Doped Oleic Acid: An Electrical Study
- Author
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Nor Kartini Idris, N. A. Nik Aziz, S. Ramli, M. Ikmar Nizam Isa, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
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Chitosan ,Oleic acid ,chemistry.chemical_compound ,Materials science ,chemistry ,Electrical resistivity and conductivity ,Inorganic chemistry ,Ionic conductivity ,Electrolyte ,Conductivity ,Thin film ,Dissociation (chemistry) - Abstract
1g chitosan was dissolved in l00 mL of 1% acetic acid solution to prepare a chitosan acetate solution. The solution was then mixed with oleic acid. This chitosan acetate‐oleic acid was then made into thin film by the solution cast technique. The conductivity of the samples was measured from ambient to elevated temperature. The highest conductivity of the chitosan‐salt with 10 wt % oleic acid (OA) at room temperature was 8.35×10−9 Scm−1. The addition of OA has increased the dielectric constant, which implies the increase of dissociation of the salt thereby producing more free ions for conducting and hence increases the ionic conductivity.
- Published
- 2008
23. Synthesis of Carbon Nanotubes from Palm DHSA Using Thermal CVD
- Author
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N. F. A. Zainal, T. I. Tunku Kudin, A. Azira, A. Z. Ahmed, S. Abdullah, M. Rusop, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
inorganic chemicals ,Materials science ,Scanning electron microscope ,Analytical chemistry ,chemistry.chemical_element ,Chemical vapor deposition ,Carbon nanotube ,law.invention ,Catalysis ,Field emission microscopy ,Nickel ,Crystallinity ,chemistry ,Chemical engineering ,law ,Fourier transform infrared spectroscopy - Abstract
We illustrate the optimization of the growth of multi‐wall carbon nanotubes (MWCNTs) using thermal chemical vapor deposition (CVD). Palm‐based dihydrostearic acid (DHSA) which was never been reported as a precursor, was used as the precursor over iron/nickel/manganese, iron/nickel/magnesium and iron/nickel/chromium trimetallic catalysts for the growth of MWCNTs. These trimetallic catalysts were prepared by sol‐gel method. MWCNTs produced were characterized by using Field Emission Scanning Electron Microscope (FE‐SEM) to indicate the production of nanotubes growth from palm DHSA. The density of the yield of MWCNTs produced differs with changes of the catalyst used during the nucleation process of MWCNTs. The crystallinity of MWCNTs was studied by X‐Ray Diffraction (XRD). Fourier Transform Infrared (FTIR) study was also been done for the prepared MWCNTs to check on the bonding occur in the produced MWCNTs.
- Published
- 2008
24. A New Look at the Electroweak Interactions of Hadrons
- Author
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Swee-Ping Chia, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Physics ,Particle physics ,Beta (velocity) ,Standard Model - Abstract
Recent theoretical results of the standard model expectations on $\sin2\beta_{\rm eff}$ from penguin-dominated $b \to s$ decays are briefly reviewed.
- Published
- 2008
25. Organic Semiconductors: Conduction Mechanisms and some Applications
- Author
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Kh. S. Karimov, H. B. Senin, I. Qazi, M. Sadrai, G. Carini, J. B. Abdullah, and D. A. Bradley
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chemistry.chemical_classification ,Fabrication ,Materials science ,business.industry ,Polymer ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Thermal conduction ,Organic semiconductor ,chemistry ,Physical vapor deposition ,Electronic engineering ,Optoelectronics ,Field-effect transistor ,Charge carrier ,business ,Quantum tunnelling - Abstract
In the current paper, we not only explain the fabrication and properties of an organic humidity sensitive field effect transistor using physical vapor deposition but also discuss the fabrication and properties of a photocapacitor made through spin‐coating technique. We also describe: (i) conduction mechanisms in organic semiconductors as hopping, band and/or tunneling one, and (ii) the possible ways to increase the mobility of charge carriers.
- Published
- 2008
26. Effect of Varying Quantum Well Thickness on the Performance of InGaN∕GaN Single Quantum Well Laser Diode
- Author
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S. M. Thahab, H. Abu Hassan, Z. Hassan, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Condensed Matter::Quantum Gases ,Physics ,Laser diode ,Condensed Matter::Other ,business.industry ,Quantum-confined Stark effect ,Quantum point contact ,Resonant-tunneling diode ,Physics::Optics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,law.invention ,law ,Quantum dot laser ,Electro-absorption modulator ,Optoelectronics ,Quantum well laser ,business ,Quantum well - Abstract
Quantum well width effect on threshold current density and optical performance of InGaN/GaN single quantum well (SQW) laser diode was determined and investigated. Various thickness (2–5 nm) of In0.13Ga0.87N wells and 12 nm GaN barriers were selected as an active region for Fabry‐Perot (FP) cavity waveguide edge emitting laser diode. The quantum confined Stark created a strong quantum well width dependence of threshold current density in the strained InGaN/GaN quantum well laser. Based on our simulation investigation, the exciton localization effect dominated the recombination emission in the thin quantum well structure; while the quantum confined stark effect (QCSE) dominated the recombination emission in the wide quantum well structure. Higher characteristic temperatures were obtained and significantly improved when the quantum well thickness was (2 to 3 nm).
- Published
- 2008
27. Effect of Annealing Temperature on Titanium Dioxide Thin Films Prepared by Sol Gel Method
- Author
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M. K. Ahmad, N. A. Rasheid, A. Zain Ahmed, S. Abdullah, M. Rusop, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
chemistry.chemical_compound ,Anatase ,Spin coating ,Materials science ,chemistry ,Chemical engineering ,Annealing (metallurgy) ,Metallurgy ,Titanium dioxide ,Thin film ,Nanocrystalline material ,Amorphous solid ,Titanium oxide - Abstract
Nanocrystalline anatase and amorphous Titanium Dioxide (TiO2) thin film have been prepared using sol‐gel method and deposited by spin coater technique. The influence of annealing temperature on the structural, surface morphology and electrical properties of the thin film is characterized by Scanning Electron Microscopy (SEM) and I‐V measurement. The result indicates that nanocrystalline anatase phase can be obtained at annealing temperature of 300 °C or above. Titanium dioxide thin films were deposited on silicon substrates. Annealing temperature at T = As deposited, 100 °C, 300 °C and 500 °C have been observed. As deposited substrates is also observed. The result indicated electrical properties of titanium dioxide thin films were changed with annealing temperatures. As the annealing temperature rises, the resistivity will be decreased. The SEM investigation showed that grain size of titanium oxide increased with higher annealing temperature. Furthermore, the SEM result indicated lattice matching between titanium dioxide and substrate is important to produce good quality titanium dioxide thin film after annealing process. The results suggest that surface porosity, electrical properties and surface morphology of titanium dioxide could be affected by changing annealing temperatures for electronic devices application.
- Published
- 2008
28. Some Weaknesses of the Relativity Theory on the Basis of Cosmological Doctrines
- Author
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B. M. Z. Shaharir, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
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Physics ,Physics::General Physics ,General relativity ,Mathematics::History and Overview ,Four-force ,Cosmological constant ,Test theories of special relativity ,Special relativity (alternative formulations) ,Computer Science::Computers and Society ,Physics::History of Physics ,General Relativity and Quantum Cosmology ,symbols.namesake ,Theoretical physics ,Theory of relativity ,Mach's principle ,symbols ,Einstein - Abstract
Fundamental principles of the Einstein's Theory of Relativity (ETR) are the continuum space‐time axiom, the Mach principle and the constancy of the speed of light in a vacuo. It is shown by Whitehead (1922/2004) and Iqbal (1934/2004) that these axioms and other physical concepts involved are not independent of the German cosmological doctrine which are incompatible with the Christian‐English and Islamic cosmological doctrines. Similar to the method of evaluating the ETR done by Whitehead and Iqbal, we reevaluate the theory based on the Malay cosmological doctrine. It is shown that the present Einstein's and Whitehead's theory of space‐time is not fully consistent with the corresponding Islamic‐Malay cosmological doctrine. Views of Islamic scholars on the compatability of the Islamic cosmological doctrine with the Einstein's Theory are refuted. It is shown that the Islamic and Malay cosmological doctrines are potentially useful in proposing an innovative theory of relativity.
- Published
- 2008
29. Simulation Of Single Channel Length Vertical Silicon MOSFET
- Author
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P. K. Ooi, K. Ibrahim, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
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Engineering ,Channel length modulation ,Silicon ,business.industry ,Transistor ,Electrical engineering ,chemistry.chemical_element ,Short-channel effect ,Symmetry (physics) ,law.invention ,Planar ,chemistry ,law ,MOSFET ,Hardware_INTEGRATEDCIRCUITS ,Optoelectronics ,business ,Communication channel - Abstract
Vertical MOSFET has been introduced in the last few decades. As planar devices become smaller and smaller, vertical MOS transistor is one of the solutions for surpassing the short channel effects and pattern transfer. Thus, it is a promising approach to achieve channel lengths between 100 nm and 25 nm. In this work, we simulate sub‐100 nm single channel length vertical silicon MOSFET. The simulations are done with using ATHENA, DEVEDIT and ATLAS from SILVACO International. Input and output electrical characteristics of the vertical MOS transistors are investigated. The short channel effects of the vertical MOSFETs are explored. Due to the structure is not symmetry, source at top and bottom is also considered. The results also compared with experimental results from other researcher.
- Published
- 2008
30. Standard Solar Model
- Author
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Lim Yaw Loong, Norhasliza Yusof, Hasan Abu Kassim, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Physics ,Standard solar model ,Epoch (reference date) ,business.industry ,Solar neutrino ,Astronomy ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Solar neutrino problem ,Solar physics ,Stars ,Physics::Space Physics ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Formation and evolution of the Solar System ,Aerospace engineering ,business ,Stellar evolution ,Astrophysics::Galaxy Astrophysics - Abstract
Solar models are important in our understanding of stars and stellar evolution. Solar models have been constructed using different methods. In this work, a solar model will be built using the fitting method. The model will incorporate the most recent input data. The model will be evolved to the current epoch starting from the zero‐age main sequence model.
- Published
- 2008
31. Vibrational Frequencies in As[sub x]Se[sub 1−x] Glass
- Author
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Ahmad Nazrul Rosli, Hasan Abu Kassim, Keshav N. Shrivastava, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Bond length ,Work (thermodynamics) ,symbols.namesake ,Condensed matter physics ,Chemistry ,symbols ,Density functional theory ,Wave function ,Raman spectroscopy ,Molecular physics ,Diatomic molecule ,Square (algebra) ,Schrödinger equation - Abstract
The density functional theory is used to make models of clusters of atoms of arsenic and selenium. We are able to determine the bond lengths and angles for which the energy of the Schroedinger equation is minimum. The vibrational spectra of the optimized clusters are computed by using several different wave functions. It is found that the double zeta wave functions work the best. For the optimized clusters, we calculated the vibrational frequencies in each case by calculating the gradients of the first principles potential. We compare the calculated values with those measured experimentally from the Raman spectra of As‐Se glass. The calculations have been done for many clusters, for example, (i) AsSe (diatomic), (ii) As2Se (linear), (iii) As2Se (triangular), (iv) As3Se (triangular), (v) As4Se (square), (vi) AsSe3 (triangular), etc. From this study we identify that linear As–Se–As for which the calculated frequency is 27.6 cm−1 is in agreement with the experimental data.
- Published
- 2008
32. Effect of Annealing Temperature on the Surface Morphology and Electrical Properties of Aluminum Doped Zinc Oxide Thin Films Prepared by Sol-Gel Spin-Coating Method
- Author
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M. H. Mamat, S. Amizam, H. A. Rafaie, H. Hashim, A. Zain Ahmed, S. Abdullah, M. Rusop, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
inorganic chemicals ,Spin coating ,Materials science ,Silicon ,Annealing (metallurgy) ,Scanning electron microscope ,Inorganic chemistry ,chemistry.chemical_element ,chemistry ,Chemical engineering ,Aluminium ,Electrical resistivity and conductivity ,Thin film ,Sol-gel - Abstract
Aluminum doped zinc oxide thin films were prepared through sol gel and spin coating technique from zinc acetate dihydrate and aluminum nitrate nanohydrate in alcoholic solution. The electrical properties and surface morphology study are investigated for the thin films annealed at 350∼500 °C. Zinc oxide thin films deposited on glass and silicon substrates were characterized using electron microscopy (SEM) and current‐voltage (I‐V) measurement scanning for surface morphology and electrical properties study respectively. The SEM investigation shows that zinc oxide thin films are denser at higher annealing temperature. The result indicates electrical properties of aluminum doped zinc oxide thin films are improved with annealing temperatures. The resistivity of aluminum doped zinc oxide thin films are decreased with annealing temperature up to 500 °C.
- Published
- 2008
33. Malaysian Secondary Physics Teachers' Perceptions towards the Teaching and Learning of Archimedes' Principle
- Author
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Khalijah Mohd Salleh, Abu Bakar Bin Abdullah, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Physics ,Secondary level ,Data collection ,Interview ,Computer science ,media_common.quotation_subject ,Pascal (programming language) ,Perception ,Pedagogy ,Mathematical skill ,Mathematics education ,Archimedes' principle ,computer ,media_common ,computer.programming_language - Abstract
An explorative study was carried out to confirm Malaysian Physics teachers' perception that Archimedes' principle is a difficult topic for secondary level students. The interview method was used for data collection. The study sample was made of nine national secondary schools teachers from Miri, Sarawak. The data was analysed qualitatively using the Atlas‐ti version 5.2 software. The findings of the study showed that i) Archimedes' principle as compared to Bernoulli's and Pascal's is the most difficult principle of hydrodynamics for students, ii) more time was given in the teaching and learning (TL) of Archimedes principle compared to the other two principles, iii) the major TL problems include conceptual understanding, application of physics principles and ideas, and lack of mathematical skills. These findings implicate the need to develop corresponding instructional materials and learning kits that can assist students' understanding of Archimedes' principle.
- Published
- 2008
34. Mechanical Properties of Malaysian Cengal Wood as Dried Sample and Under Fiber Saturated Point
- Author
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Chan Kok Sheng, H. B. Senin, S. Hamdan, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Materials science ,Softening point ,Drop (liquid) ,Modulus ,Young's modulus ,Raw material ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,symbols ,Lignin ,Composite material ,Glass transition ,Softening - Abstract
The Cengal wood samples which are obtained from Tenaga National Berhad (TNB), is a raw material for heavy construction industry. The compression test is carried out by using an Instron Machine Series‐IX at different temperatures for the purpose of determining and understanding the mechanical properties of Cengal wood under fiber saturated point and as dried samples. Analysis is made from the results in the form of Young's modulus, E plotted against the temperature. From the test, the Cengal wood does not show a glass transition or softening when dried up to 140 °C because there is no significant decrease in the value of E during heating. For fiber saturated point, the glass transition temperature occurs at 40 °C when the E value is about 190 MPa while the second rapid drop occurs at 60 °C (155 MPa), which is due to the softening temperature of lignin. After the softening point, the wood becomes too soft and undergoes the process of decomposition due to small value of E.
- Published
- 2008
35. Erbium Plating on Nanostructured Silicon Using Immersion Technique
- Author
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A. Saifollah, M. Rusop, H. A. Rafaie, S. Amizam, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Erbium ,chemistry.chemical_compound ,Photoluminescence ,Materials science ,Hydrofluoric acid ,Silicon ,chemistry ,X-ray photoelectron spectroscopy ,Analytical chemistry ,chemistry.chemical_element ,Electrolyte ,Fourier transform infrared spectroscopy ,Luminescence - Abstract
The effects of immersion time and quantity of Erbium plated on Nanostructured Silicon (NSi) have been studied. Nanostructured Silicon was prepared by electrochemical method with an electrolyte composed of Hydrofluoric acid and Ethanol. The Erbium plating process was carried out by immersion technique with electrolyte composed of ErCl3 and Ethanol. The photoluminescence (PL) effect on NSi samples have been studied and shows a PL intensity is improves at certain immersion time and the PL peak shifts to the blue luminescence. The presence of Erbium conformed by X‐ray Photoelectron Spectroscopy (XPS). Fourier Transform Infrared Spectroscopy (FTIR) was also performed to study the chemical functional group changes after the plating process. The possible mechanism of the effects will be discussed in this paper.
- Published
- 2008
36. Phase Analysis of Fringe Pattern In Shearography
- Author
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M. Y. Yusof, W. S. Wan Abdullah, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Interferometry ,Materials science ,Optics ,Shearography ,business.industry ,Phase (waves) ,Astronomical interferometer ,Calibration ,Phase analysis ,business ,Phase shift module ,Piezoelectricity - Abstract
This paper discusses the phase analysis of interference pattern from coherent light Nd:YAG 532 nm laser source. The Twyman‐Green Interferometer set‐up is used for generating the fringe pattern in the phase calibration. The piezoelectric transducer (PZT) is used to achieve the required phase shift of the fringe pattern. It was found that the system required 8.8 volts of out‐put DC voltage to shift 2π radians phase. The accuracy of optical phase measurement of the interference pattern is analyzed by wrapped phases of three‐phase stepping and four‐phase stepping procedures. Comparison of the experimental phase measurement data and the theoretical phase calculations are also highlighted.
- Published
- 2008
37. The Effect Of Dose Exposure In Electron Beam Lithography
- Author
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M. M. A. Hanapiah, Y. K. Sin, K. Ibrahim, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Conventional transmission electron microscope ,Optics ,Materials science ,business.industry ,Proximity effect (electron beam lithography) ,Scanning transmission electron microscopy ,Low-voltage electron microscope ,X-ray lithography ,Electron beam-induced deposition ,business ,Focused ion beam ,Electron-beam lithography - Abstract
Electron beam lithography is one of the most promising of nanolithographic techniques. The setup is similar to a Scanning Electron Microscope (SEM) and often a scanning electron microscope is used. EBL is able to provide high resolution patterning. However, the effect of electron scattering in resist and substrate leads to an undesired influence in the regions adjacent to those exposed by the electron beam. This effect is called the proximity effect. In this paper, we investigated the effect of dose exposure in Electron beam lithography (EBL) and proximity effect. We also show the image for several of dose exposure.
- Published
- 2008
38. Ab-initio Study Of Solvated Methionine-tRNA[sup met] And Alanine-tRNA[sup ala] Molecules
- Author
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Hadieh Monajemi, Wan Ahmad Tajuddin Wan Abdullah, Sharifuddin M. Zain, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
chemistry.chemical_classification ,Alanine ,chemistry.chemical_compound ,Crystallography ,Methionine ,Chemistry ,Stereochemistry ,Transfer RNA ,Ab initio ,Peptide bond ,Peptide ,Ribosome ,Amino acid - Abstract
The tRNA molecule takes suitable amino acids to the ribosome for the formation of peptide bonds. In starting the peptide chain, the first amino acid taken to the ribosome is methionine. We have carried out calculations on the methionine‐tRNA and alanine‐tRNA complexes using mixed quantum mechanics ab‐initio and molecular mechanics method. The total energies and dipole moments have also been calculated. The amino acids chosen for this study, alanine and methionine have almost the same hydropath index. It is important to understand the physical properties and the environmental conditions in which the dipeptides cause the tRNA to attach to a wrong amino acid. One of the properties studied is the dielectric environment in which the bonding occurs.
- Published
- 2008
39. Ion Beam Measurements of a Dense Plasma Focus Device Using CR 39 Nuclear Track Detectors
- Author
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S. K. Ngoi, S. L. Yap, C. S. Wong, A. R. Saadah, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Secondary ion mass spectrometry ,Ion beam deposition ,Ion implantation ,Ion beam ,Physics::Plasma Physics ,Chemistry ,Physics::Accelerator Physics ,Laser beam quality ,Atomic physics ,Ion gun ,Focused ion beam ,Ion source - Abstract
The project is carried out using a small Mather type plasma focus device powered by a 15 kV, 30 μF capacitor. The filling gas used is argon. The ion beam generated is investigated by both time resolved and time integrated methods. Investigation on the dynamic of the current sheath is also carried out in order to obtain an optimum condition for ion beam production. The angular distribution of the ion emission is measured at positions of 0° (end‐on), 45° and 90° (side‐on) by using CR‐39 nuclear track detectors. The divergence of the ion beam is also determined using these detectors. A biased ion collector is used for time resolved measurement of the ion beam. Time of flight technique is employed for the determination of the ion beam energy. Average ion beam energy obtained is about 180 keV. The ion beam produced can be used for applications such as material surface modification and ion implantation.
- Published
- 2008
40. The Theory of the Quantum Hall Effect
- Author
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Keshav N. Shrivastava, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Physics ,Angular momentum ,Quantum mechanics ,Fractional quantum Hall effect ,Quasiparticle ,Charge (physics) ,Quantum Hall effect ,Ground state ,Magnetic field ,Spin-½ - Abstract
Laughlin's theory of fractional charges is worked out in detail for small charges from 1/3 till 1/101. There is a small deviation between computed values and those obtained from the closed form expression. The ground state energy crosses that of the charge‐density waves. We develop a theory of fractional charges by using the quantum mechanics of angular momentum. We find that fractional charges can be expressed in terms of spin and the values of charges 0, 1, 1/3, 2/3, 2/5, 3/5, …, are produced. The angular momenta eigen values when subjected to flux quantization, yield plateaus of energies which are independent of the magnetic field. In this way we are able to predict that charges of ±2e, ±6e, ±10e, ±14e, …, are produced. The higher order term in the flux quantization also produces quasiparticles of charges of ±4e. These calculated values of the charges are the same as those found in the experimental data of quantum Hall effect in graphene, which is a mono‐atomic layer of carbon. Since the charge of the ...
- Published
- 2008
41. Ultrasonic Goniometry Measurement of Aquilaria sp (Gaharu) Wood
- Author
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Mohamad Pauzi Ismail, Mat Rasol Awang, Mohd Noorul Ikhsan Ahmad, Amry Amin Abas, Mohd. Fajri Osman, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Corner reflector ,Materials science ,biology ,Goniometer ,Aquilaria ,Ultrasonic sensor ,Composite material ,biology.organism_classification - Abstract
This paper describes the results of ultrasonic goniometry measurement in Aquilaria (gaharu) wood. Ultrasonic wave was transmitted into the surface of gaharu wood and the reflected amplitudes by corner reflection were measured. The measurements were performed on gaharu sample with dimension of about 3 mm×15 mm×25 mm by attaching to corner reflector goniometer made of mild steel. The measurement results are explained and discussed.
- Published
- 2008
42. Fabrication and Performance of Ceramic Er123 Oxygen Gas Sensor
- Author
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M. Hassan, A. K. Yahya, K. H. Ku Hamid, Z. Awang, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Fabrication ,Materials science ,Analytical chemistry ,Oxide ,Hot spot (veterinary medicine) ,Partial pressure ,Volumetric flow rate ,chemistry.chemical_compound ,chemistry ,visual_art ,visual_art.visual_art_medium ,Relative density ,Ceramic ,Absorption (chemistry) - Abstract
Oxygen sensing properties of Er123 ceramic material utilizing hot‐spot phenomenon have been investigated. Bulk Er123 ceramic with relative density of 72 % was synthesized using solid‐state method and single‐phase structure of the material was confirmed by X‐ray diffraction. The Er123 sensor was fabricated by cutting the bulk sample into a rectangular rod shape. I‐V characterizations of the sensor before and after appearance of the hot spot were conducted in a chamber with controlled flow rate and partial pressure of oxygen and nitrogen gases. After appearance of the hot spot, the output current strongly depended on oxygen partial pressure (pO2) at a particular selected voltage. The sensor showed good sensing properties with minimum required electric field of about 1.7 V/cm for 0.025% to 100% pO2. The sensor showed very good reproducibility and stability of output current. The oxygen sensing properties are explained in terms of absorption of oxygen gas by the hot spot before dissociating into oxide ions an...
- Published
- 2008
43. Photoacoustics Cell for investigations of Solids at Various Temperatures
- Author
-
Hasan A. Alwi, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Photoacoustic effect ,Optical fiber ,Materials science ,Opacity ,Microphone ,business.industry ,Thermal diffusivity ,law.invention ,Optics ,law ,Thermal ,Tube (fluid conveyance) ,business ,Helmholtz resonator - Abstract
This paper describes the construction and testing at room temperature of a resonant photoacoustic cell which may be used to carry out photoacoustic measurements of opaque samples at various temperatures from 77 K to 300 K. It has the shape of the Helmholtz resonator with a microphone separated from the sample by a long narrow tube. An optical fiber leads the laser light to the sample. The photoacoustic cell was tested by measuring thermal diffusivity of various solid samples at room temperature. The testing shows that the photoacoustic cell is successful in measuring thermal diffusivities of various opaque samples.
- Published
- 2008
44. Ab Initio Study of Polonium
- Author
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Noriza Ahmad Zabidi, Hasan Abu Kassim, Keshav N. Shrivastava, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Crystallography ,Valence (chemistry) ,Chemistry ,Ab initio quantum chemistry methods ,Ab initio ,Density functional theory ,Electronic structure ,Crystal structure ,Cubic crystal system ,Atomic physics ,Valence electron - Abstract
Polonium is the only element with a simple cubic (sc) crystal structure. Atoms in solid polonium sit at the corners of a simple cubic unit cell and no where else. Polonium has a valence electron configuration 6s26p4 (Z = 84). The low temperature α‐phase transforms into the rhombohedral (trigonal) β structure at ∼348 K. The sc α‐Po unit cell constant is a = 3.345 A. The beta form of polonium (β‐Po) has the lattice parameters, aR = 3.359 A and a rhombohedral angle 98°13′. We have performed an ab initio electronic structure calculation by using the density functional theory. We have performed the calculation with and without spin‐orbit (SO) coupling by using both the LDA and the GGA for the exchange‐correlations. The k‐points in a simple cubic BZ are determined by R (0.5, 0.5, 0.5), Γ (0, 0, 0), X (0.5, 0, 0), M (0.5, 0.5, 0) and Γ (0, 0, 0). Other directions of k‐points are Γ (0, 0, 0), X (0.5, 0, 0), R (0.5, 0.5, 0.5) and Γ (0, 0, 0). The SO splittings of p states at the Γ point in the GGA+SO scheme for α‐...
- Published
- 2008
45. Synthesis, Characterization and Growth Mechanism of ZnO Nano-flower by Thermal Chemical Vapor Deposition Method at Low Deposition Temperature
- Author
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A. R. Hartini, S. Amizam, M. H. Mamat, S. Abdullah, M. Rusop, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Photoluminescence ,Materials science ,Silicon ,chemistry ,Scanning electron microscope ,Nano ,technology, industry, and agriculture ,Analytical chemistry ,chemistry.chemical_element ,Zinc ,Chemical vapor deposition ,Combustion chemical vapor deposition ,Thin film - Abstract
Photoluminescence and morphology studies of Zinc Oxide (ZnO) thin films prepared by using Thermal Chemical Vapor Deposition (Thermal‐CVD) were investigated. The ZnO compound was synthesized from zinc acetate dehydrate which act as a starting material to form the ZnO thin films. It was deposited on silicon with low deposition temperature ranging from 400–600 °C with Au as a catalyst assisted. Surface morphology of the samples was examined by Scanning Electron Microscope and photoluminescence properties were studied using Photoluminescence Spectrometer. The surface morphologies of the ZnO nano‐flower structure was obviously obtained at deposition temperature of 400 °C. The individual nano‐rods diameter of nano‐flower is about 100–350 nm, but the end of nano‐rods are very sharp which is the size is less than 50 nm. Possible growth mechanism of ZnO nano‐flower also discussed. Room temperature PL spectra from the ZnO nano‐flower revealed a strong UV emission and broad green emission. This result is very useful...
- Published
- 2008
46. The Methodology Effects on Surface Morphology Pattern of Porous Semiconductors
- Author
-
Khalid M. Omar, N. K. Ali, Z. Hassan, Md R. Hashim, H. Abu Hassan, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Materials science ,Morphology (linguistics) ,Fabrication ,Etching (microfabrication) ,Scanning electron microscope ,Nanotechnology ,Laser power scaling ,Composite material ,Porosity ,Porous silicon ,Porous medium - Abstract
Porous GaP have studied fabricated by using an argon‐ion laser beam (LIE) of energy 2.41 eV. We have studied the surface morphology of porous layers obtained using a Scanning Electron Microscope (SEM). The morphology of porous GaP layers changes rapidly with laser power densities and irradiation times. This advanced fabrication method have been used for synthesis porous silicon (p‐Si). The optical characteristic was used to illustrate changes in surface morphology and the intensity of emission of porous form as a function of etching conditions. The surface morphology studies have demonstrated the characterization of porous silicon. As well as both the size and shape of the structure depend on the nature concentration of etchant solution. The different size of pores form at different area of GaN shows that the etching rate is not uniform through out the whole surface of GaN. The porous GaN generated by electrochemical etching technique does not always produce similar surface morphology. However, the averag...
- Published
- 2008
47. Preparation and Characterization of the Lead Sulfide Nanostructured Thin Film
- Author
-
M. Sasani Ghamsari, S. Radiman, M. Ambar Yarmo, M. A. A. Hamid, A. Bananej, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
chemistry.chemical_compound ,Materials science ,chemistry ,Absorption spectroscopy ,Surface plasmon ,X-ray crystallography ,Nanoparticle ,Nanotechnology ,Self-assembly ,Lead sulfide ,Thin film ,Layer (electronics) - Abstract
lead sulfide nanostructured thin film was prepared from colloidal lead sulfide nanoparticles with natural deposition technique. The size of PbS nanoparticles has been determined in the base of optical absorption spectrum. The influence of preparation method on the film surface morphology was studied by atomic force microscopy, and x‐ray diffraction. Experimental results have shown that the thin film uniformity has been improved when the number of deposited layer increased. Double layered PbS nanothin film has a self assembly morphology and can be used for surface plasmon applications.
- Published
- 2008
48. Introducing the Modeling of Uniform-Size Particle of Single Media Filter by Using Stella
- Author
-
Ahmad Jusoh, Sunny Goh Eng Giap, Mohd Zamri Ibrahim, Izan Jaafar, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Engineering ,business.industry ,Control engineering ,Granular material ,law.invention ,Filter design ,Filter (video) ,Media filter ,law ,Table (database) ,User interface ,business ,Process engineering ,Reliability (statistics) ,Filtration - Abstract
Granular filter is widely used in removing suspended substance from treating water. Its reliability is well accepted and has been modified into different modes of operation and media combination, etc., in order to accommodate its different purposes of usage. A more conventional method in supplying adequate volume of potable water with minimum expenses involve, gravity flow of rapid filtration is normally used. Conventionally, engineer refers to filter design criteria in tabulated form of table before designing filtration unit. A slight different from conventional design parameters would normally require time for re‐calculation. The current studies have been conducted to develop a simulation model with user interface that is governed by some well accepted equations, such as, Carmen‐Kozeny and Ives‐Gregory models. This work is done to ease the work of engineers in making design decision. The simulated results are the total amount of water produced, time required in reaching particular head‐loss, amount of particulate mass accumulated within the filter, and the designated total head‐loss. Overall, the developed simulation model could be effectively implemented for filter design purpose, after some verification through laboratory experimentation or compilation of past experiments.
- Published
- 2008
49. Conductivity Studies of Plasticized-poly(methylmethacrylate) (PMMA) Polymer Electrolytes Films
- Author
-
A. Ahmad, K. B. Md Isa, L. Othman, Z. Osman, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
chemistry.chemical_classification ,Materials science ,Analytical chemistry ,Plasticizer ,Polymer ,Electrolyte ,Conductivity ,Dielectric spectroscopy ,chemistry.chemical_compound ,chemistry ,Propylene carbonate ,Polymer chemistry ,Trifluoromethanesulfonate ,Ethylene carbonate - Abstract
In the present study, five systems of samples have been prepared by the solution casting technique. Polymethylmethacrylate (PMMA) is used as a based polymer. Ethylene carbonate (EC) and propylene carbonate (PC) as plasticizers. The salt that was selected for this study is lithium triflate (LiCF3SO3). The pure PMMA sample is taken as a reference. The five systems are the (PMMA–EC) system, the (PMMA–PC) system, the (PMMA‐LiCF3SO3) system, the ([PMMA‐EC]‐LiCF3SO3) system and the ([PMMA–PC]‐LiCF3SO3) system. The conductivity for each system is characterized using impedance spectroscopy. The conductivity of the pure PMMA, the (PMMA–EC) system and the (PMMA–PC) system at room temperature is 2.37×10−9 Scm−1, 3.63×10−8 Scm−1 and 4.18×10−8 Scm−1 respectively. On addition of salt in the (PMMA–LiCF3SO3) system, the conductivity is increased by two orders of magnitude. The conductivity for the ([PMMA–EC]‐LiCF3SO3) system and the ([PMMA–PC]‐LiCF3SO3) system is 3.54×10−5 Scm−1 and 2.06×10−5 Scm−1 respectively. The cond...
- Published
- 2008
50. P—Type Conduction of ZnO Thin Film by Codoping Technique
- Author
-
H. Abdul Hamid, M. J. Abdullah, A. Abdul Aziz, H. B. Senin, G. Carini, J. B. Abdullah, and D. A. Bradley
- Subjects
Argon ,Materials science ,chemistry ,Silicon ,Annealing (metallurgy) ,Aluminium ,Sputtering ,Electrical resistivity and conductivity ,Inorganic chemistry ,Analytical chemistry ,chemistry.chemical_element ,Sputter deposition ,Thin film - Abstract
Aluminium and zinc target were co—sputtered on silicon (111) substrates using DC magnetron sputtering in the pure argon atmosphere. These films were then underwent the thermal annealing in different ratios of nitrogen and oxygen for 1 hour to form thin oxide films. P—type conduction in ZnO thin films have been realized by the Al—N codoping method, whereby the lowest resistivity of 3.41×10−3 Ω⋅cm and the highest carrier concentration of 1.54×1022 cm−3 was achieved for sample prepared at annealed temperature of 300 °C.
- Published
- 2008
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