Displaying publications 21 - 40 of 470 in total

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  1. Fulltext Enhanced Optoelectronic Properties of PFO/Fluorol 7GA Hybrid Light Emitting Diodes via Additions of TiO₂ Nanoparticles
    Al-Asbahi BA, Haji Jumali MH, AlSalhi MS
    Polymers (Basel), 2016 Sep 06;8(9).
    PMID: 30974607 DOI: 10.3390/polym8090334
    The effect of TiO₂ nanoparticle (NP) content on the improvement of poly(9,9'-di-n-octylfluorenyl-2,7-diyl) (PFO)/Fluorol 7GA organic light emitting diode (OLED) performance is demonstrated here. The PFO/Fluorol 7GA blend with specific ratios of TiO₂ NPs was prepared via a solution blending method before being spin-coated onto an indium tin oxide (ITO) substrate to act as an emissive layer in OLEDs. A thin aluminum layer as top electrode was deposited onto the emissive layer using the electron beam chamber. Improvement electron injection from the cathode was achieved upon incorporation of TiO₂ NPs into the PFO/Fluorol 7GA blend, thus producing devices with intense luminance and lower turn-on voltage. The ITO/(PFO/Fluorol 7GA/TiO₂)/Al OLED device exhibited maximum electroluminescence intensity and luminance at 25 wt % of TiO₂ NPs, while maximum luminance efficiency was achieved with 15 wt % TiO₂ NP content. In addition, this work proved that the performance of the devices was strongly affected by the surface morphology, which in turn depended on the TiO₂ NP content.
    Matched MeSH terms: Electrodes
  2. Fulltext BIOMASS ACTIVATED CARBON PROPERTIES THROUGH ACTIVATION METHOD FOR SUPERCAPACITOR – A MINI-REVIEW
    Madhiyah Yahaya Bermakai, Nor Farahin Jafri, Norha Abdul Hadi
    Journal of Academia Universiti Teknologi MARA Negeri Sembilan, 2021;9(1):8-13.
    MyJurnal
    Recently, the development of activated carbon electrodes from agricultural waste biomass for application in carbon-based electrode of supercapacitor is increasing. The use of agricultural waste biomass as a precursor for the production of activated carbon become popular because it is economical, easily available and also beneficial in reducing waste disposal problem in agricultural industries. In this review, the biomass material for activated carbon using various activators is presented. The effects of activating methods which is physical and chemical activation on the properties of activated carbons are reviewed. Carbonaceous materials with high surface area, which is above 1000 m2g-1 and good porosity with total pore volume approximately 1.0 cm3g-1 promote fast ion-transport, making them an ideal choice to be used in supercapacitor. Previous study had shown that different types of activation method influence significantly on the properties of activated carbon produced. Producing a high porosity and high surface area of activated carbon are essentials to fabricate a high quality of supercapacitor. With proper treatment, it is found that many agriculture wastes have high potential and carry good properties as an electrode in supercapacitor.
    Matched MeSH terms: Electrodes
  3. Solution-Processable Vertical Organic Light-Emitting Transistors (VOLETs) with Directly Deposited Silver Nanowires Intermediate Source Electrode
    Sarjidan MAM, Shuhaimi A, Majid WHA
    J Nanosci Nanotechnol, 2019 Nov 01;19(11):6995-7003.
    PMID: 31039852 DOI: 10.1166/jnn.2019.16724
    A simple spin-coating process for fabricating vertical organic light-emitting transistors (VOLETs) is realized by utilizing silver nanowire (AgNW) as a source electrode. The optical, electrical and morphological properties of the AgNW formation was initially optimized, prior VOFET fabrication. A high molecular weight of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] MEH-PPV was used as an organic semiconductor layer in the VOFET in forming a multilayer structure by solution process. It was found that current density and luminance intensity of the VOLET can be modulated by a small magnitude of gate voltage. The modulation process was induced by changing an injection barrier via gate voltage bias. A space-charge-limited current (SCLC) approach in determining transistor mobility has been introduced. This preliminary and fundamental work is beneficial towards all-solution processing display devices.
    Matched MeSH terms: Electrodes
  4. Fulltext A Fluidics-Based Double Flexural Membrane Piezoelectric Micromachined Ultrasonic Transducer (PMUT) for Wide-Bandwidth Underwater Acoustic Applications
    Ahmad KA, Rahman MFA, Zain KAM, Haron MN, Manaf AA
    Sensors (Basel), 2021 Aug 19;21(16).
    PMID: 34451023 DOI: 10.3390/s21165582
    In acoustic receiver design, the receiving sensitivity and bandwidth are two primary parameters that determine the performance of a device. The trade-off between sensitivity and bandwidth makes the design very challenging, meaning it needs to be fine-tuned to suit specific applications. The ability to design a PMUT with high receiving sensitivity and a wide bandwidth is crucial to allow a wide spectrum of transmitted frequencies to be efficiently received. This paper presents a novel structure involving a double flexural membrane with a fluidic backing layer based on an in-plane polarization mode to optimize both the receiving sensitivity and frequency bandwidth for medium-range underwater acoustic applications. In this structure, the membrane material and electrode configuration are optimized to produce good receiving sensitivity. Simultaneously, a fluidic backing layer is introduced into the double flexural membrane to increase the bandwidth. Several piezoelectric membrane materials and various electrode dimensions were simulated using finite element analysis (FEA) techniques to study the receiving performance of the proposed structure. The final structure was then fabricated based on the findings from the simulation work. The pulse-echo experimental method was used to characterize and verify the performance of the proposed device. The proposed structure was found to have an improved bandwidth of 56.6% with a receiving sensitivity of -1.8864 dB rel 1 V µPa. For the proposed device, the resonance frequency and center frequency were 600 and 662.5 kHz, respectively, indicating its suitability for the targeted frequency range.
    Matched MeSH terms: Electrodes
  5. Fulltext Construction Of An Electrical Pain Stimulator
    Ling, Booi Cie
    Ann Dent, 1997;4(1):-.
    MyJurnal
    The construction of an electrical pain stimulator was described.
    The parameters of pulse width and frequency on the quality of
    pain stimulation was determined. The best design and construction
    of the electrode for the stimulator was produced.
    Matched MeSH terms: Electrodes
  6. Fulltext Symmetrical supercapacitor using coconut shell-based activated carbon
    Ajina, Ahmida, Isa, Dino
    Pertanika Journal of Science & Technology, 2010;18(2):-.
    MyJurnal
    Two different supercapacitor configurations were fabricated using coconut shell-based activated
    carbon. Results for cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge-discharge measurements are presented and discussed for both configurations. The results show that coconut shell-based activated carbon is viable economical alternative electrode material to expensive activated carbon (AC) and carbon nano tubes (CNT). Meanwhile, the calculations from the charge-discharge characteristics show that the disk-shape supercapacitor, with 10% polyvinylidene fluoride binder (PVdF), has the highest specific capacitance (70F/g). Thus, the testing shows that the flat-laminated super-capacitor with 10% binder (PVdF) has the lowest (10.1ohms). Sources of high equivalent series resistance (ESR) are proposed and methods of reducing it are also discussed in this paper.
    Matched MeSH terms: Electrodes
  7. Fulltext Heel effect: dose mapping and profiling for mobile c-arm fluoroscopy unit toshiba SXT-100A
    Husaini Salleh, Supian Samat, Mohd Khalid Matori, Muhammad Jamal Md Isa, Mohd Ramli Arshad, Shahrul Azlan Azizan, et al.
    Jurnal Sains Nuklear Malaysia, 2014;26(2):9-13.
    MyJurnal
    Heel Effect is the well known phenomena in x-ray production. It contributes the effect to image
    formation and as well as scattered radiation. But there is paucity in the study related to heel effect.
    This study is for mapping and profiling the dose on the surface of water phantom by using mobile
    C-arm unit Toshiba SXT-1000A. Based on the result the dose profile is increasing up to at least
    about 57% from anode to cathode bound of the irradiated area. This result and information can be
    used as a guide to manipulate this phenomenon for better image quality and radiation safety for
    this specific and dedicated fluoroscopy unit.
    Matched MeSH terms: Electrodes
  8. Fulltext Bioanode as a limiting factor to biocathode performance in microbial electrolysis cells
    Lim SS, Yu EH, Daud WRW, Kim BH, Scott K
    Bioresour Technol, 2017 Aug;238:313-324.
    PMID: 28454006 DOI: 10.1016/j.biortech.2017.03.127
    The bioanode is important for a microbial electrolysis cell (MEC) and its robustness to maintain its catalytic activity affects the performance of the whole system. Bioanodes enriched at a potential of +0.2V (vs. standard hydrogen electrode) were able to sustain their oxidation activity when the anode potential was varied from -0.3 up to +1.0V. Chronoamperometric test revealed that the bioanode produced peak current density of 0.36A/m(2) and 0.37A/m(2) at applied potential 0 and +0.6V, respectively. Meanwhile hydrogen production at the biocathode was proportional to the applied potential, in the range from -0.5 to -1.0V. The highest production rate was 7.4L H2/(m(2) cathode area)/day at -1.0V cathode potential. A limited current output at the bioanode could halt the biocathode capability to generate hydrogen. Therefore maximum applied potential that can be applied to the biocathode was calculated as -0.84V without overloading the bioanode.
    Matched MeSH terms: Electrodes
  9. Fulltext Image quality of two full field digital mammography using a female breast phantom
    Chelliah, Kanaga Kumari, Ang, Wee Chin, Abd Aziz Tajuddin, Arasaratnam, Shantini A., Suraya Aziz, Laila Suryani Elias
    Jurnal Sains Kesihatan Malaysia, 2009;7(1):65-72.
    MyJurnal
    Digital mammography has been progressively introduced in screening centers and the concern is to achieve an image of diagnostic value which would be able to detect early changes in the breast tissue. The aim of this study was to evaluate the image quality of mammograms using quantitative and qualitative methods of two FFDM systems with variations in breast thickness and anode/filter combination. This study was done from January to April 2008 with two FFDM systems; Siemens Mammomat NovationDR at Diagnostic Imaging Department, Hospital Kuala Lumpur and Hologic Lorad Selenia at Breast Clinic, National Cancer Society. A CIRS012A tissue equivalent breast phantom (4, 5 and 6 cm) thickness was used to obtain images in the craniocaudal plane with 26-32 kVp and a combination of molybdenum/molybdenum (Mo/Mo) and molybdenum/rhodium (Mo/Rh) anode/filter. For the qualitative evaluation, two independent radiologist with a minimum of five years experience was used to score the images. Wilcoxon Sign Rank Test showed that there are no significant differences (p > 0.05) in image quality between both the FFDM systems. Kappa analysis had a poor agreement between the scores given by the two radiologists. The quantitative analysis using Mann-Whitney test showed that there are significant differences (p < 0.05) between the SNR values of both FFDM systems. Although the qualitative evaluation was similar, the study showed that Lorad Selenia had a significantly superior SNR value, hence would be a better tool to detect early changes in the breast tissue. This study also demonstrated that a lower kVp is more suitable with molybdenum filter and as the breast thickness is increased rhodium filter with higher kVp displayed better quality images.
    Matched MeSH terms: Electrodes
  10. Fulltext Intercorrelation of surface free energy and anode capacity of alumnium alloy anodes
    Muhamad Daud, Sarimah Mahat, Mohd Sharif Sattar
    Journal of Nuclear and Related Technologies, 2006;2006(1):19-24.
    MyJurnal
    Surface free energies have been evaluated from Young’s moduli and lattice parameter data of five aluminium alloys with varying amounts of stanum to determine the inter-correlation with anode capacity of the alloys. The composition containing ~1.47%Sn exhibits a minimum in the surface free energy which accounts for the decrease in the tendency of the alloy to undergo passivation thus resulting in a higher anode capacity of 2478Ah/kg at ≈ 0.08mA/cm 2 , current density. The results showed that aluminium alloy containing certain amount of stanum has lowered surface free energy, leading to reduction in passive film thickness and reduces metal/oxide bond strength. These factors in turn result in a better cathodic protection property of aluminium alloy containing stanum.
    Matched MeSH terms: Electrodes
  11. Fulltext Preliminary characterization study based on cyclic voltammetry and reliability of a fabricated Au/Ti microfluidic three-electrode sensor
    Hamzah, I.H., Sidek, O., Abd Manaf, A.
    ASM Science Journal, 2010;4(2):142-148.
    MyJurnal
    A preliminary study was carried out to fabricate a three electrode system based on electrochemical sensoring. The cyclic voltammetry (CV) technique was chosen to select the type of metal suitable for evaporation and to compare the results produced from the fabricated gold electrode with the conventional macro-electrode system. The methodology and apparatus used involved low cost apparatus and methodology such as soft lithography, wet-etching, thermal evaporation, direct current sputtering, polymethylmethacrylate moulding and polydimethylsiloxane coating. The experiment was conducted at a fixed scan rate of 100 mV/s by using 0.01 M K3Fe(CN)6 in 0.1M KCl and well known method using Randles-Sevcik equation, peak current ratio and voltage separation was used to analyze the characterization on the fabricated sensors. Electrodes of 6.5 mm2 and 0.26 mm2 were fabricated to prove the adsorption effect of the reactant and the influence of the electrode area on the value of the peak current. CV analysis proved that the fabricated sensor was reliable for a range of 24 h at 25ºC room temperature.
    Matched MeSH terms: Electrodes
  12. Fulltext 2-hydroxyethyl cellulose as natural binder in electrodes for solid-state proton battery: construction and preliminary results
    Ramlli, M.A., Isa, M.I.N., Yu, K.X., Siew, Y.W.
    ASM Science Journal, 2018;11(101):47-55.
    MyJurnal
    Affordable and greener materials were extensively studied in electrode fabrication for Liion
    based batteries but less interest was shown to proton battery. Hence, in this work,
    a methodology on preparing a natural based binder for proton battery was reported. 2-
    Hydroxyethyl Cellulose (2HEC) was chosen to replace PVDF commercial binder in electrode
    for ZnSO4|MnO2 proton battery configuration. SEM image shows good surface formation
    for both anode and cathode with good porous structure. OCV result shows that the cell
    improved the stable voltage of reference cell of 0.7 V to 0.9 V after 24 hours. The first
    discharge of the cell took 6 hours and 49 minutes at 0.005mA and shows good potential for
    rechargebility test.
    Matched MeSH terms: Electrodes
  13. Determination of HOMO and LUMO of [6,6]-Phenyl C61-butyric Acid 3-ethylthiophene ester and poly (3-octyl-thiophene-2, 5-diyl) through voltametry characterization
    Ashkan Shafiee, Muhamad Mat Salleh, Muhammad Yahaya
    Sains Malaysiana, 2011;40.
    HOMO and LUMO of organic compounds are basic parameters for the design and fabrication of an organic solar cell. This paper presents a technique to obtain HOMO and LUMO of an n-type polymer of [6,6]-phenyl C61-butyric acid 3-ethylthiophene ester (PCBE) and a p-type polymer of poly (3-octyl-thiophene-2, 5-diyl) (P3OT). The energy of band gap for each material has been calculated using optical absorption spectrum. Cyclic Voltammetry was used to estimate the oxidation potential and energy band diagram consequently. The experiments were carried out in a three-electrode cell consisting of a platinum working electrode, a platinum counter electrode and a SCE reference electrode. P3OT showed energy band gap equal to 1.83 eV with HOMO and LUMO equal to 5.59 eV and 3.76 eV, respectively. PCBE showed energy band gap equal to 1.96 eV with HOMO and LUMO equal to 5.87 eV and 3.91 eV, respectively. Based on energy band diagram that was constructed from this experimental result, the couple materials may be successfully used to fabricate the feasible organic solar cells.
    Matched MeSH terms: Electrodes
  14. Effects of inter-electrode gap and discharge voltage on EUV emission from stainless steel vacuum spark plasma
    Saboohi S, Yap S, Chan L, Wong C
    Sains Malaysiana, 2012;41:879-884.
    The emission of Extreme Ultra Violet (EUV) from plasma produced by vacuum spark discharge using stainless steel as anode material was investigated. The operating pressure for all the experiments carried out was maintained at below 10-4 mbar. The discharge voltage tested was from 8 kV to 20 kV. The inter-electrode distance suitable for high intensity and reproducible EUV emissions was found to be in the range of 2.6 mm to 4.6 mm. The output EUV energy scaled as ~ V02, where V0 is the discharge voltage.
    Matched MeSH terms: Electrodes
  15. New hybridization approach of titanium organometallic: PANi thin films as room temperature gas sensors
    Izura Izzuddin, Mohammad Hafizuddin Jumali, Muhammad Yahaya, Muhamad Mat Salleh
    Sains Malaysiana, 2012;41:1017-1021.
    The aim of this research was to investigate the ability of organometallic titanium-PANi hybrid materials as gas sensor at room temperature. To form the hybrid materials, commercially available polyaniline (PANi) powder were directly added into organometallic titanium sols which was synthesized using the sol gel method. The composite films were prepared via spin coating technique followed by electrode deposition for sensors fabrication. Five different organometallic titanium:PANi ratios namely 1 wt% to 5 wt% of PANi were prepared for this experiment. For gas sensing test, all samples were exposed to ethanol vapour. The sensing mode is based on the variation in the electrical conductivity due to the
    interaction between the gas molecules and the film. It was observed that the composite sensors required appropriate ratio to exhibit optimum sensing properties. This finding proved that the hybridization process is successful and offered much cheaper and easier method for fabrication of room temperature gas sensor.
    Matched MeSH terms: Electrodes
  16. One-step anodization of aluminum at room temperature
    Araoyinbo AO, Ahmad Fauzi M, Sreekantan S, Azizan Aziz
    Sains Malaysiana, 2009;38.
    The formation of nano pores on aluminum at 30oC- 38oC, employing a one step anodization technique which does not require removing the oxide layer formed is presented. A 20% phosphoric acid electrolyte (concentration higher than the normal anodization concentration of 5 to 10%) at a cell potential of 60 volts was used. A platinum electrode was used as the cathode electrode while the aluminum substrate as the anode electrode. A dc powered electrochemical cell to provide the required amount of current density (without the use of temperature controlled water bath) suitable or necessary for pore formation at room temperature was employed. The results obtained show that pore formation at room temperature is achievable and the pore diameter ranged between 80-120 nm.
    Matched MeSH terms: Electrodes
  17. An analysis of the electron trajectory in the vicinity of GaAs quantum dot
    Hanafi Ithnin, Khalid Kasmin M, Radzi Mat Isa A, Shaari A, Armed R
    Sains Malaysiana, 2014;43:819-825.
    Quantum dots being an interesting class of nanostructures are considered potential prototype systems for novel nano-devices such as single electron transistor (sET). Here in this research, we present an analysis of the electron trajectory in the vicinity of gallium arsenide (GaAs) quantum dot. To perform this study, DFT based methodology is employed to optimize structure of quantum dot and determining the electrostatic potential around the dot. Under the influence of obtained electrostatic potential, trajectory of the moving electron towards the dot is investigated. The results showed that GaAs quantum dot have negative and positive potential surfaces that influence the electron interaction with the dot. These results motivate the development of SET electrode channel where the electron moves towards the dot on the surface with positive potential rather than negative potential surface.
    Matched MeSH terms: Electrodes
  18. Fulltext Photophysical and Electroluminescence Characteristics of Polyfluorene Derivatives with Triphenylamine
    Zhang Q, Wang PI, Ong GL, Tan SH, Tan ZW, Hii YH, et al.
    Polymers (Basel), 2019 May 09;11(5).
    PMID: 31075895 DOI: 10.3390/polym11050840
    In this work, polymers of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-triphenylamine] with side chains containing: pyrene (C1), diphenyl (C2), naphthalene (C3), and isopropyl (C6) structures were synthesized via a Suzuki coupling reaction. The structures were verified using NMR and cyclic voltammetry measurements provide the HOMO and LUMO of the polymers. The polymer with pyrene (C1) and naphthalene (C3) produced photoluminescence in the green while the polymer with the side chain containing diphenyl (C2) and isopropyl (C6) produce dual emission peaks of blue-green photoluminescence (PL). In order to examine the electroluminescence properties of the polymers, the solutions were spin-coated onto patterned ITO anode, dried, and subsequently coated with an Al cathode layer to form pristine single layer polymer LEDs. The results are compared to a standard PFO sample. The electroluminescence spectra resemble the PL spectra for C1 and C3. The devices of C2, C3, and C6 exhibit voltage-dependent EL. An additional red emission peak was detected for C2 and C6, resulting in spectra with peaks at 435 nm, 490 nm, and 625 nm. The effects of the side chains on the spectral characteristics of the polymer are discussed.
    Matched MeSH terms: Electrodes
  19. How does saline backflow affect the treatment of saline-infused radiofrequency ablation?
    Kho ASK, Ooi EH, Foo JJ, Ooi ET
    Comput Methods Programs Biomed, 2021 Nov;211:106436.
    PMID: 34601185 DOI: 10.1016/j.cmpb.2021.106436
    BACKGROUND AND OBJECTIVE: Saline infusion is applied together with radiofrequency ablation (RFA) to enlarge the ablation zone. However, one of the issues with saline-infused RFA is backflow, which spreads saline along the insertion track. This raises the concern of not only thermally ablating the tissue within the backflow region, but also the loss of saline from the targeted tissue, which may affect the treatment efficacy.

    METHODS: In the present study, 2D axisymmetric models were developed to investigate how saline backflow influence saline-infused RFA and whether the aforementioned concerns are warranted. Saline-infused RFA was described using the dual porosity-Joule heating model. The hydrodynamics of backflow was described using Poiseuille law by assuming the flow to be similar to that in a thin annulus. Backflow lengths of 3, 4.5, 6 and 9 cm were considered.

    RESULTS: Results showed that there is no concern of thermally ablating the tissue in the backflow region. This is due to the Joule heating being inversely proportional to distance from the electrode to the fourth power. Results also indicated that larger backflow lengths led to larger growth of thermal damage along the backflow region and greater decrease in coagulation volume. Hence, backflow needs to be controlled to ensure an effective treatment of saline-infused RFA.

    CONCLUSIONS: There is no risk of ablating tissues around the needle insertion track due to backflow. Instead, the risk of underablation as a result of the loss of saline due to backflow was found to be of greater concern.

    Matched MeSH terms: Electrodes
  20. Unidirectional ablation minimizes unwanted thermal damage and promotes better thermal ablation efficacy in time-based switching bipolar radiofrequency ablation
    Ooi EH, Ooi ET
    Comput Biol Med, 2021 10;137:104832.
    PMID: 34508975 DOI: 10.1016/j.compbiomed.2021.104832
    Switching bipolar radiofrequency ablation (bRFA) is a thermal treatment modality used for liver cancer treatment that is capable of producing larger, more confluent and more regular thermal coagulation. When implemented in the no-touch mode, switching bRFA can prevent tumour track seeding; a medical phenomenon defined by the deposition of cancer cells along the insertion track. Nevertheless, the no-touch mode was found to yield significant unwanted thermal damage as a result of the electrodes' position outside the tumour. It is postulated that the unwanted thermal damage can be minimized if ablation can be directed such that it focuses only within the tumour domain. As it turns out, this can be achieved by partially insulating the active tip of the RF electrodes such that electric current flows in and out of the tissue only through the non-insulated section of the electrode. This concept is known as unidirectional ablation and has been shown to produce the desired effect in monopolar RFA. In this paper, computational models based on a well-established mathematical framework for modelling RFA was developed to investigate if unidirectional ablation can minimize unwanted thermal damage during time-based switching bRFA. From the numerical results, unidirectional ablation was shown to produce treatment efficacy of nearly 100%, while at the same time, minimizing the amount of unwanted thermal damage. Nevertheless, this effect was observed only when the switch interval of the time-based protocol was set to 50 s. An extended switch interval negated the benefits of unidirectional ablation.
    Matched MeSH terms: Electrodes
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