Displaying publications 101 - 120 of 284 in total

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  1. Fulltext Optical Properties and Conductivity of PVA-H3PO4 (Polyvinyl Alcohol-Phosphoric Acid) Film Blend Irradiated by γ-Rays
    Susilawati S, Prayogi S, Arif MF, Ismail NM, Bilad MR, Asy'ari M
    Polymers (Basel), 2021 Mar 28;13(7).
    PMID: 33800592 DOI: 10.3390/polym13071065
    This study assesses the optical properties and conductivity of PVA-H3PO4 (polyvinyl alcohol-phosphoric acid) polymer film blend irradiated by gamma (γ) rays. The PVA-H3PO4 polymer film blend was prepared by the solvent-casting method at H3PO4 concentrations of 75 v% and 85 v%, and then irradiated up to 25 kGy using γ-rays from the Cobalt-60 isotope source. The optical absorption spectrum was measured using an ultraviolet-visible spectrophotometer over a wavelength range of 200 to 700 nm. It was found that the absorption peaks are in three regions, namely two peaks in the ultraviolet region (310 and 350 nm) and one peak in the visible region (550 nm). The presence of an absorption peak after being exposed to hυ energy indicates a transition of electrons from HOMO to LUMO within the polymer chain. The study of optical absorption shows that the energy band gap (energy gap) depends on the radiation dose and the concentration of H3PO4 in the polymer film blend. The optical absorption, absorption edge, and energy gap decrease with increasing H3PO4 concentration and radiation dose. The interaction between PVA and H3PO4 blend led to an increase in the conductivity of the resulting polymer blend film.
    Matched MeSH terms: Electrons
  2. Fulltext Synthesis of Porous Proton Ion Conducting Solid Polymer Blend Electrolytes Based on PVA: CS Polymers: Structural, Morphological and Electrochemical Properties
    M Nofal M, Aziz SB, Hadi JM, Abdulwahid RT, Dannoun EMA, Marif AS, et al.
    Materials (Basel), 2020 Oct 30;13(21).
    PMID: 33143345 DOI: 10.3390/ma13214890
    In this study, porous cationic hydrogen (H+) conducting polymer blend electrolytes with an amorphous structure were prepared using a casting technique. Poly(vinyl alcohol) (PVA), chitosan (CS), and NH4SCN were used as raw materials. The peak broadening and drop in intensity of the X-ray diffraction (XRD) pattern of the electrolyte systems established the growth of the amorphous phase. The porous structure is associated with the amorphous nature, which was visualized through the field-emission scanning electron microscope (FESEM) images. The enhancement of DC ionic conductivity with increasing salt content was observed up to 40 wt.% of the added salt. The dielectric and electric modulus results were helpful in understanding the ionic conductivity behavior. The transfer number measurement (TNM) technique was used to determine the ion (tion) and electron (telec) transference numbers. The high electrochemical stability up to 2.25 V was recorded using the linear sweep voltammetry (LSV) technique.
    Matched MeSH terms: Electrons
  3. Effects of degree of substitution and irradiation doses on the properties of hydrogel prepared from carboxymethyl-sago starch and polyethylene glycol
    Zahib IR, Md Tahir P, Talib M, Mohamad R, Alias AH, Lee SH
    Carbohydr Polym, 2021 Jan 15;252:117224.
    PMID: 33183648 DOI: 10.1016/j.carbpol.2020.117224
    Carboxymethyl starch (CMS) was produced from sago starch via carboxymethylation. The CMS with different degree of substitution (DS) ranges from 0.4 to 0.8 were mixed with polyethylene glycol (PEG) of different molecular weight and distilled water and the hydrogel was cured by electron beam irradiation with doses ranging from 25 to 35 kGy. The results revealed that CMS-PEG hydrogels with DS 0.4 give the optimum gel content when radiated at 30 kGy and with PEG 600. Thermogravimetric analysis (TGA) revealed that there are two phases exist in CMS with DS 0.4 in contrast to the three steps decomposition occurs in DS 0.6 and 0.8. It shows that the CMS with DS 0.4 is more thermally stable. Surface morphology revealed crosslinking among the blends when subjected into the radiation dose. The study shows both radiation and PEG addition improved most of the properties of CMS irrespective of the DS value.
    Matched MeSH terms: Electrons
  4. Evidence for Top Quark Production in Nucleus-Nucleus Collisions
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.
    Phys Rev Lett, 2020 Nov 27;125(22):222001.
    PMID: 33315428 DOI: 10.1103/PhysRevLett.125.222001
    Ultrarelativistic heavy ion collisions recreate in the laboratory the thermodynamical conditions prevailing in the early universe up to 10^{-6}  sec, thereby allowing the study of the quark-gluon plasma (QGP), a state of quantum chromodynamics (QCD) matter with deconfined partons. The top quark, the heaviest elementary particle known, is accessible in nucleus-nucleus collisions at the CERN LHC, and constitutes a novel probe of the QGP. Here, we report the first evidence for the production of top quarks in nucleus-nucleus collisions, using lead-lead collision data at a nucleon-nucleon center-of-mass energy of 5.02 TeV recorded by the CMS experiment. Two methods are used to measure the cross section for top quark pair production (σ_{tt[over ¯]}) via the selection of charged leptons (electrons or muons) and bottom quarks. One method relies on the leptonic information alone, and the second one exploits, in addition, the presence of bottom quarks. The measured cross sections, σ_{tt[over ¯]}=2.54_{-0.74}^{+0.84} and 2.03_{-0.64}^{+0.71}  μb, respectively, are compatible with expectations from scaled proton-proton data and QCD predictions.
    Matched MeSH terms: Electrons
  5. Theory and experiment of optical absorption of platinum nanoparticles synthesized by gamma radiation
    Gharibshahi E, Saion E, Johnston RL, Ashraf A
    Appl Radiat Isot, 2019 May;147:204-210.
    PMID: 30953937 DOI: 10.1016/j.apradiso.2019.02.015
    Platinum nanoparticles were synthesized using the gamma radiolytic technique in an aqueous solution containing Platinum tetraammine chloride in presence of poly vinyl pyrrolidone, isopropanol, tetrahydrofuran and deionized water. The gamma irradiation was carried out in a60Co gamma source chamber and the particle size was found to decrease from 4.88 to 3.14 nm on increasing the gamma radiation dose from 80 to 120 kGy. UV-visible absorption spectra were measured and revealed two steady absorption maxima at 216 and 264 nm in the UV region, which was blue shifted (i.e. toward lower wavelength) with decreasing particle size. By taking the conduction electrons of an isolated particle that are not entirely free, but instead bound to their respective quantum levels, the optical absorption of platinum nanoparticles can be calculated via intra-band quantum excitation for particle sizes similar to those measured experimentally. We found that the calculated absorption maxima of electronic excitations matched the measured absorption maxima well. This finding suggests that the optical absorption of metal nanoparticles commonly applied in nanoscience and nanotechnology can be described accurately by the quantum excitation of conduction electrons.
    Matched MeSH terms: Electrons
  6. Observation of Single Top Quark Production in Association with a Z Boson in Proton-Proton Collisions at sqrt[s]=13  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2019 Apr 05;122(13):132003.
    PMID: 31012605 DOI: 10.1103/PhysRevLett.122.132003
    The observation of single top quark production in association with a Z boson and a quark (tZq) is reported. Events from proton-proton collisions at a center-of-mass energy of 13 TeV containing three charged leptons (either electrons or muons) and at least two jets are analyzed. The data were collected with the CMS detector in 2016 and 2017 and correspond to an integrated luminosity of 77.4fb^{-1}. The increased integrated luminosity, a multivariate lepton identification, and a redesigned analysis strategy improve significantly the sensitivity of the analysis compared to previous searches for tZq production. The tZq signal is observed with a significance well over 5 standard deviations. The measured tZq production cross section is σ(pp→tZq→tℓ^{+}ℓ^{-}q)=111±13(stat)_{-9}^{+11}(syst)  fb, for dilepton invariant masses above 30 GeV, in agreement with the standard model expectation.
    Matched MeSH terms: Electrons
  7. Energy Band Gap Modulation in Nd-Doped BiFeO3/SrRuO3 Heteroepitaxy for Visible Light Photoelectrochemical Activity
    Tan KH, Chen YW, Van CN, Wang H, Chen JW, Lim FS, et al.
    ACS Appl Mater Interfaces, 2019 Jan 09;11(1):1655-1664.
    PMID: 30561192 DOI: 10.1021/acsami.8b17758
    The ability of band offsets at multiferroic/metal and multiferroic/electrolyte interfaces in controlling charge transfer and thus altering the photoactivity performance has sparked significant attention in solar energy conversion applications. Here, we demonstrate that the band offsets of the two interfaces play the key role in determining charge transport direction in a downward self-polarized BFO film. Electrons tend to move to BFO/electrolyte interface for water reduction. Our experimental and first-principle calculations reveal that the presence of neodymium (Nd) dopants in BFO enhances the photoelectrochemical performance by reduction of the local electron-hole pair recombination sites and modulation of the band gap to improve the visible light absorption. This opens a promising route to the heterostructure design by modulating the band gap to promote efficient charge transfer.
    Matched MeSH terms: Electrons
  8. Ultrastructural studies of developing goat oocytes in vitro
    Rajikin MH, Yusoff M, Abdullah RB
    Theriogenology, 1994 Nov 01;42(6):1003-16.
    PMID: 16727604
    The structure and distribution of organelles within developing goat oocytes at various stages of incubation were studied. In oocytes with 5 or more layers of cumulus cells, at 0 h of incubation, the zona pellucida had developed although zonation was not evident. Lipid bodies were present but no mitochondria were observed. At 20 h, the zona pellucida had differentiated into thicker and thinner regions. Clusters of membrane-bound electron-transparent bodies were present in the perivitelline space. The mitochondria were fully developed, distributed evenly and usually in close proximity with dilated endoplasmic reticula. Cortical granules were distributed at the periphery. At 40 h of incubation, a number of mitochondria was hooded. In oocytes of 2 to 4 layers of cumulus cells at 0 h, the zona pellucida was penetrated by cumulus cell processes, and the mitochondria were not well developed. However, in 20-h incubated oocytes, fully developed mitochondria, many of which were hooded, could be observed. Clusters of membrane-bound electron-transparent bodies were also observed, while cortical granules were at the periphery. In cumulus-free oocytes, zonation within the zona pellucida was indistinct. Very few vesicles and lipid bodies were observed. At 20 h, mitochondria were sparsely distributed and were not well developed and lacked cristae. At 40 h, the zona pellucida was less compact, and the membrane-bound electron-transparent bodies were less numerous compared with those of the other groups. Endoplasmic reticula were not dilated, and cortical granules were few and had no definite pattern of distribution.
    Matched MeSH terms: Electrons
  9. Naked Eye Chemosensing of Anions by Schiff Bases
    Junaid HM, Batool M, Harun FW, Akhter MS, Shabbir N
    Crit Rev Anal Chem, 2020 Sep 08.
    PMID: 32897731 DOI: 10.1080/10408347.2020.1806703
    Spectacular color change during a chemical reaction is always fascinating. A variety of chemosensors including Schiff bases have been reported for selective as well as sensitive recognition of ions. This review explains the use of Schiff bases as color changing agents in the detection of anions. This magic of colors is attributed to change in the electronic structure of the system during reaction. Schiff base chemosensors are easy to synthesize, inexpensive and can be used for visual sensing of different ions. Development of Schiff base chemosensors is commonly based on the interactions between polar groups of Schiff bases and ionic species and the process of charge transfer, electron transfer and hydrogen bonding between Schiff bases and ionic species cause the color of the resultant to be changed. Therefore, designing of simple Schiff base chemosensors which are capable of selective sensing of different anions has attracted considerable interest. In particular, naked eye sensing through color change is important and useful since it allows sensing of ions through color changes without using any instrumental technique.HighlightsNaked eye sensors are of much interest these days due to their visual detection properties rather employing complex instrumentation.Optical sensors are sensitive, selective, cost effective and robust.The magic of color change is fascinating factor in detection by these sensors.The color change may be attributed by interaction between anion and Schiff base by different mechanism i.e. electron transfer, charge transfer, hydrogen bonding, ICT etc.LOD data is an evidence of their great efficiency.
    Matched MeSH terms: Electrons
  10. Electrochemical Long Period Fiber Grating Sensing for Electroactive Species
    Okazaki T, Orii T, Tan SY, Watanabe T, Taguchi A, Rahman FA, et al.
    Anal Chem, 2020 07 21;92(14):9714-9721.
    PMID: 32551577 DOI: 10.1021/acs.analchem.0c01062
    We present an electrochemical long period fiber grating (LPFG) sensor for electroactive species with an optically transparent electrode. The sensor was fabricated by coating indium tin oxide onto the surface of LPFG using a polygonal barrel-sputtering method. LPFG was produced by an electric arc-induced technique. The sensing is based on change in the detection of electron density on the electrode surface during potential application and its reduction by electrochemical redox of analytes. Four typical electroactive species of methylene blue, hexaammineruthenium(III), ferrocyanide, and ferrocenedimethanol were used to investigate the sensor performance. The concentrations of analytes were determined by the modulation of the potential as the change in transmittance around the resonance band of LPFG. The sensitivity of the sensor, particularly to methylene blue, was high, and the sensor responded to a wide concentration range of 0.001 mM to 1 mM.
    Matched MeSH terms: Electrons
  11. Co-Electrolysis-Assisted Decomposition of Hydroxylammonium Nitrate-Fuel Mixtures Using Stainless Steel-Platinum Electrodes
    Chai WS, Sun D, Cheah KH, Li G, Meng H
    ACS Omega, 2020 Aug 11;5(31):19525-19532.
    PMID: 32803046 DOI: 10.1021/acsomega.0c01804
    Hydroxylammonium nitrate (HAN) is a promising green propellant because of its low toxicity, high volumetric specific impulse, and reduced development cost. Electrolytic decomposition of HAN is an efficient approach to prepare it for further ignition and combustion. This paper describes the investigation of a co-electrolysis effect on electrolytic decomposition of HAN-fuel mixtures using stainless steel-platinum (SS-Pt) electrodes. For the first time, different materials were utilized as electrodes to alter the cathodic reaction, which eliminated the inhibition effect and achieved a repeatable and consistent electrolytic decomposition of HAN solution. Urea and methanol were added as fuel components in the HAN-fuel mixtures. When the mass ratio of added urea ≥20%, the electrolytic decomposition of a HAN-urea ternary mixture achieved 67% increment in maximum gas temperature (Tgmax) and 185% increment in overall temperature increasing rate over the benchmark case of HAN solution. The co-electrolysis of urea released additional electrons into the mixtures and enhanced the overall electrolytic decomposition of HAN. In contrast, the addition of methanol did not improve the Tgmax but only increased the overall temperature increasing rate. This work has important implications in the development of an efficient and reliable electrolytic decomposition system of HAN and its mixtures for propulsion applications.
    Matched MeSH terms: Electrons
  12. Rapid fabrication of oxygen defective α-Fe2O3(110) for enhanced photoelectrochemical activities
    Mohamad Noh MF, Ullah H, Arzaee NA, Ab Halim A, Abdul Rahim MAF, Mohamed NA, et al.
    Dalton Trans, 2020 Sep 14;49(34):12037-12048.
    PMID: 32869793 DOI: 10.1039/d0dt00406e
    Defect engineering is increasingly recognized as a viable strategy for boosting the performance of photoelectrochemical (PEC) water splitting using metal oxide-based photoelectrodes. However, previously developed methods for generating point defects associated with oxygen vacancies are rather time-consuming. Herein, high density oxygen deficient α-Fe2O3 with the dominant (110) crystal plane is developed in a very short timescale of 10 minutes by employing aerosol-assisted chemical vapor deposition and pure nitrogen as a gas carrier. The oxygen-defective film exhibits almost 8 times higher photocurrent density compared to a hematite photoanode with a low concentration of oxygen vacancies which is prepared in purified air. The existence of oxygen vacancies improves light absorption ability, accelerates charge transport in the bulk of films, and promotes charge separation at the electrolyte/semiconductor interface. DFT simulations verify that oxygen-defective hematite has a narrow bandgap, electron-hole trapped centre, and strong adsorption energy of water molecules compared to pristine hematite. This strategy might bring PEC technology another step further towards large-scale fabrication for future commercialization.
    Matched MeSH terms: Electrons
  13. Molecular orbitals of delocalized electron clouds in neuronal domains
    Poznanski RR, Cacha LA, Latif AZA, Salleh SH, Ali J, Yupapin P, et al.
    Biosystems, 2019 Sep;183:103982.
    PMID: 31195028 DOI: 10.1016/j.biosystems.2019.103982
    We have further developed the two-brains hypothesis as a form of complementarity (or complementary relationship) of endogenously induced weak magnetic fields in the electromagnetic brain. The locally induced magnetic field between electron magnetic dipole moments of delocalized electron clouds in neuronal domains is complementary to the exogenous electromagnetic waves created by the oscillating molecular dipoles in the electro-ionic brain. In this paper, we mathematically model the operation of the electromagnetic grid, especially in regard to the functional role of atomic orbitals of dipole-bound delocalized electrons. A quantum molecular dynamic approach under quantum equilibrium conditions is taken to illustrate phase differences between quasi-free electrons tethered to an oscillating molecular core. We use a simplified version of the many-body problem to analytically solve the macro-quantum wave equation (equivalent to the Kohn-Sham equation). The resultant solution for the mechanical angular momentum can be used to approximate the molecular orbital of the dipole-bound delocalized electrons. In addition to non-adiabatic motion of the molecular core, 'guidance waves' may contribute to the delocalized macro-quantum wave functions in generating nonlocal phase correlations. The intrinsic magnetic properties of the origins of the endogenous electromagnetic field are considered to be a nested hierarchy of electromagnetic fields that may also include electromagnetic patterns in three-dimensional space. The coupling between the two-brains may involve an 'anticipatory affect' based on the conceptualization of anticipation as potentiality, arising either from the macro-quantum potential energy or from the electrostatic effects of residual charges in the quantum and classical subsystems of the two-brains that occurs through partitioning of the potential energy of the combined quantum molecular dynamic system.
    Matched MeSH terms: Electrons
  14. Fulltext Design, synthesis and biological profile of heterocyclic benzimidazole analogues as prospective antimicrobial and antiproliferative agents
    Tahlan S, Kumar S, Ramasamy K, Lim SM, Shah SAA, Mani V, et al.
    BMC Chem, 2019 Dec;13(1):50.
    PMID: 31384798 DOI: 10.1186/s13065-019-0567-x
    Background: Nitrogen containing heterocycles are widely used and investigated by pharmaceutical industry, as they are important in discovery and designing of new drug molecules. Drugs with a benzimidazole nucleus possess exclusive structural features and electron-rich atmosphere, which enable them to bind to a number of biologically important targets and result in a wide range of activities. This has served as the basis of the present study whereby new scaffolds with benzimidazole moiety were designed and synthesized.

    Methods: The structures of synthesized compounds were confirmed by physicochemical and spectral means. The synthesized compounds were screened for their antimicrobial and antiproliferative activities by tube dilution and Sulforhodamine B (SRB) assays, respectively.

    Results and conclusion: The in vitro biological screening results revealed that compound Z24 exhibited promising antimicrobial and anticancer activities which are comparable to standards.

    Matched MeSH terms: Electrons
  15. Taguchi design-assisted immobilization of Candida rugosa lipase onto a ternary alginate/nanocellulose/montmorillonite composite: Physicochemical characterization, thermal stability and reusability studies
    Mohd Hussin FNN, Attan N, Wahab RA
    Enzyme Microb Technol, 2020 May;136:109506.
    PMID: 32331714 DOI: 10.1016/j.enzmictec.2019.109506
    Biomass from oil palm frond leaves (OPFL) is an excellent reservoir of lignocellulosic material which full potential remains untapped. This study aimed to statistically optimize the covalent immobilization of Candida rugosa lipase (CRL) onto a ternary support comprised of OPFL derived nanocellulose (NC) and montmorillonite (MMT) in alginate (ALG) (CRL-ALG/NC/MMT). The coarser topology and the presence of characteristic spherical globules in the field emission scanning electron micrographs and atomic force micrographs, respectively, supported the existence of CRL on ALG/NC/MMT. In addition, amide peaks at 3478 and 1640 cm-1 in the fourier transform infrared spectra affirmed that CRL was covalently bonded to ALG/NC/MMT. The optimized Taguchi Design-assisted immobilization of CRL onto ALG/NC/MMT (7 h of immobilization, 35℃, pH 5, 7 mg/mL protein loading) gave a production yield of 92.89 % of ethyl levulinate (EL), as proven by gas chromatography-mass spectrometric ([M] +m/z 144, C7H12O3), FTIR and nuclear magnetic resonance (CAS-539-88-8) data. A higher optimal reaction temperature (50℃) and the reusability of CRL-ALG/NC/MMT for up to 9 esterification cycles substantiated the appreciable structural rigidification of the biocatalyst by ALG/NC/MMT, which improved the catalytic activity and thermal stability of the lipase.
    Matched MeSH terms: Electrons
  16. Production and characterization of graphene from carbonaceous rice straw by cost-effect extraction
    Uda MNA, Gopinath SCB, Hashim U, Halim NH, Parmin NA, Uda MNA, et al.
    3 Biotech, 2021 May;11(5):205.
    PMID: 33868892 DOI: 10.1007/s13205-021-02740-9
    This paper describes the synthesis of graphene-based activated carbon from carbonaceous rice straw fly ash in an electrical furnace and the subsequent potassium hydroxide extraction. The produced graphene has a proper morphological structure; flakes and a rough surface can be observed. The average size of the graphene was defined as up to 2000 nm and clarification was provided by high-resolution microscopes (FESEM and FETEM). Crystallinity was confirmed by surface area electron diffraction. The chemical bonding from the graphene was clearly observed, with -C=C- and O-H stretching at peaks of 1644 cm-1 and 3435 cm-1, respectively. Impurities in the graphene were found using X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The measured size, according to zeta-potential analysis, was 8722.2 ± 25 nm, and the average polydispersity index was 0.576. The stability of the mass reduction was analyzed by a thermogravimetric at 100 °C, with a final reduction of ~ 11%.
    Matched MeSH terms: Electrons
  17. Superior photoelectrocatalytic performance of ternary structural BiVO4/GQD/g-C3N4 heterojunction
    Samsudin MFR, Ullah H, Tahir AA, Li X, Ng YH, Sufian S
    J Colloid Interface Sci, 2021 Mar 15;586:785-796.
    PMID: 33198982 DOI: 10.1016/j.jcis.2020.11.003
    Herein, we performed an encyclopedic analysis on the photoelectrocatalytic hydrogen production of BiVO4/g-C3N4 decorated with reduced graphene oxide (RGO) or graphene quantum dots (GQDs). The differences between RGO and GQDs as an electron mediator was revealed for the first time in the perspective of theoretical DFT analysis and experimental validation. It was found that the incorporation of GQDs as an electron mediator promotes better photoelectrocatalytic hydrogen performance in comparison to the RGO. The addition of GQD can significantly improve the activity by 25.2 and 75.7% in comparison to the BiVO4/RGO/g-C3N4 and binary composite samples, respectively. Correspondingly, the BiVO4/GQD/g-C3N4 attained the highest photocurrent density of 19.2 mA/cm2 with an ABPE of 0.57% without the presence of any sacrificial reagents. This enhancement is stemming from the low photocharge carrier transfer resistance which was further verified via DFT study. The DFT analysis revealed that the BiVO4/GQD/g-C3N4 sample shared their electronic cloud density through orbital hybridization while the BiVO4/RGO/g-C3N4 sample show less mutual sharing. Additionally, the charge redistribution of the GQDs-composite at the heterostructure interface articulates a more stable and stronger heterojunction than the RGO-composite. Notably, this study provides new insights on the effect of different carbonaceous materials (RGO and GQDs) which are often used as an electron mediator to enhance photocatalytic activity.
    Matched MeSH terms: Electrons
  18. Aging effects on physical and electrical properties of nano-structured MgZnO thin films for carbon nanotube applications
    Ahmad R, Salina M, Mamat MH, Teh AA, Kara M, Rusop M, et al.
    J Nanosci Nanotechnol, 2012 Oct;12(10):8153-7.
    PMID: 23421193
    This paper addresses the growth of nano-structured MgZnO thin films by sol-gel spin coating method which will be used as a template layer to grow carbon nanotubes. The nano-structured MgZnO films were deposited on platinized (100) silicon substrates. In this work, we focused on the effect of aging and Mg content on the film structure and resistivity. Sols with Mg content of 10, 30 and 50 at.% were subjected to aging times of between 3 to 240 hours. Results from scanning (SEM) and field emission scanning electron (FESEM) microscopes and surface profiler (SP) showed that the sol aging increased the thickness, grain size and surface roughness for aging up to 240 hours. The energy dispersive analysis by X-ray (EDAX) confirmed the element of Mg in the ZnO films. The electrical resistivity also increased with aging time as confirmed by four point probe method. The results suggest that appropriate aging of the sol is important for improving physical quality and electrical performance of MgZnO thin films derived from sol-gel technique.
    Matched MeSH terms: Electrons
  19. Photoelectrochemical behaviour of uniform growth TiO2 nanotubes via bubble blowing synthesised in ethylene glycol with hydrogen peroxide
    Lai CW, Sreekantan S, Lockman Z
    J Nanosci Nanotechnol, 2012 May;12(5):4057-66.
    PMID: 22852347
    Uniformly sized TiO2 nanotubes with high aspect ratios were synthesised on a large substrate (100 mm x 100 mm) via the bubbling system through anodisation of Ti in ethylene glycol containing 5 wt% NH4F and 5 wt% H2O2. The benefits of bubbling system in producing uniformly sized TiO2 nanotubes throughout the Ti foil are illustrated. Moreover, the effects of applied voltage and fluoride content on the resulting nanotubes were also considered. Such uniform sized TiO2 nanotubes are a key to produce hydrogen efficiently using PEC cell. The results show higher photocurrent responses for the high aspect ratio, uniform TiO2 nanotubes because of excellent interfacial electron transfer.
    Matched MeSH terms: Electrons
  20. Visible light photoelectrochemical performance of W-loaded TiO2 nanotube arrays: structural properties
    Lai CW, Sreekantan S
    J Nanosci Nanotechnol, 2012 Apr;12(4):3170-4.
    PMID: 22849082
    Well aligned TiO2 nanotubes were successfully synthesized by anodization of Ti foil at 60 V in a fluorinated bath comprised of ethylene glycol with 5 wt% of NH4F and 5 wt% of H2O2. In order to enhance the visible light absorption and photoelectrochemical response of pure TiO2 nanotube arrays, a mixed oxide system (W-TiO2) was investigated. W-TiO2 nanotube arrays were prepared using radio-frequency (RF) sputtering to incorporate the W into the lattice of TiO2 nanotube arrays. The W atoms occupy the substitutional position within the vacancies of TiO2 nanotube arrays. The as-anodized TiO2 is amorphous in nature while the annealed TiO2 is anatase phase. The mixed oxide (W-TiO2) system in suitable TiO2 phase plays important roles in efficient electron transfers due to the reduction in electron-hole recombination. In this article, the effect of the sputtered W into the as-anodized/annealed TiO2 nanotube arrays on the photoelectrochemical response was presented.
    Matched MeSH terms: Electrons
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