Displaying publications 1 - 20 of 1347 in total

  1. Sim KS, Cheng Z, Chuah HT
    Scanning, 2004 12 23;26(6):287-95.
    PMID: 15612206
    A new technique based on the statistical autoregressive (AR) model has recently been developed as a solution to signal-to-noise (SNR) estimation in scanning electron microscope (SEM) images. In the present study, we propose to cascade the Lagrange time delay (LTD) estimator with the AR model. We call this technique the mixed Lagrange time delay estimation autoregressive (MLTDEAR) model. In a few test cases involving different images, this model is found to present an optimum solution for SNR estimation problems under different noise environments. In addition, it requires only a small filter order and has no noticeable estimation bias. The performance of the proposed estimator is compared with three existing methods: simple method, first-order linear interpolator, and AR-based estimator over several images. The efficiency of the MLTDEAR estimator, being more robust with noise, is significantly greater than that of the other three methods.
    Matched MeSH terms: Microscopy, Electron, Scanning
  2. Mamat H, Hill SE
    J Food Sci Technol, 2014 Sep;51(9):1998-2005.
    PMID: 25190856 DOI: 10.1007/s13197-012-0708-x
    Fat is an important ingredient in baking products and it plays many roles in providing desirable textural properties of baking products, particularly biscuit. In this study, the effect of fat types on dough rheological properties and quality of semi-sweet biscuit (rich tea type) were investigated using various techniques. Texture profile and extensibility analysis were used to study the dough rheology, while three-point bend test and scanning electron microscopy were used to analyse the textural characteristics of final product. TPA results showed that the type of fat significantly influenced dough textural properties. Biscuit produced with higher solid fat oil showed higher breaking force but this was not significantly different when evaluated by sensory panel. Scanning electron microscopy showed that biscuit produced with palm mid-fraction had an open internal microstructure and heterogeneous air cells as compared to other samples.
    Matched MeSH terms: Microscopy, Electron, Scanning
  3. Somidin F, Maeno H, Tran XQ, D McDonald S, Mohd Salleh MAA, Matsumura S, et al.
    Materials (Basel), 2018 Nov 09;11(11).
    PMID: 30423946 DOI: 10.3390/ma11112229
    In-situ observations of the polymorphic transformation in a single targeted Cu₆Sn₅ grain constrained between Sn-0.7 wt % Cu solder and Cu-Cu₃Sn phases and the associated structural evolution during a solid-state thermal cycle were achieved via a high-voltage transmission electron microscope (HV-TEM) technique. Here, we show that the monoclinic η'-Cu₆Sn₅ superlattice reflections appear in the hexagonal η-Cu₆Sn₅ diffraction pattern upon cooling to isothermal 140 °C from 210 °C. The in-situ real space imaging shows that the η'-Cu₆Sn₅ contrast pattern is initiated at the grain boundary. This method demonstrates a new approach for further understanding the polymorphic transformation behavior on a real solder joint.
    Matched MeSH terms: Microscopy, Electron, Transmission
  4. Lee GE
    Data Brief, 2020 Feb;28:104958.
    PMID: 31890799 DOI: 10.1016/j.dib.2019.104958
    The morphological data of Malesian Lejeunea is described in detail based on examination of about 600 fresh specimens and 1500 herbarium specimens of Lejeunea from other herbaria. Scanning electron microscopy (SEM) images and photographs illustrating the characters of Lejeunea are presented.
    Matched MeSH terms: Microscopy, Electron, Scanning
  5. Sim KS, Huang YH
    Scanning, 2015 Nov-Dec;37(6):381-8.
    PMID: 25969945 DOI: 10.1002/sca.21226
    This is the extended project by introducing the modified dynamic range histogram modification (MDRHM) and is presented in this paper. This technique is used to enhance the scanning electron microscope (SEM) imaging system. By comparing with the conventional histogram modification compensators, this technique utilizes histogram profiling by extending the dynamic range of each tile of an image to the limit of 0-255 range while retains its histogram shape. The proposed technique yields better image compensation compared to conventional methods.
    Matched MeSH terms: Microscopy, Electron, Scanning
  6. Ng KH, Gan SK
    Malays J Pathol, 1990 Jun;12(1):27-33.
    PMID: 2090887
    We investigated microwave-stimulated fixation of tissues for transmission electron microscopy using a domestic microwave oven operating at a frequency of 2.45 GHz with an output power of 500W. Microwave-stimulated fixation, in 4% glutaraldehyde, of fresh rat kidney, liver, heart and brain tissues was compared to conventional fixation. Human renal biopsies were similarly studied. Electron microscopy showed excellent ultrastructural preservation comparable to that obtained by conventional fixation. The optimal temperature range for microwave-stimulated fixation was found to lie between 50 degrees C and 55 degrees C. Our results indicate that microwave-stimulated fixation is a rapid and reproducible technique and can be effectively applied to routine diagnostic pathology.
    Matched MeSH terms: Microscopy, Electron*
  7. Dee CF, Chong SK, Rahman SA, Omar FS, Huang NM, Majlis BY, et al.
    Nanoscale Res Lett, 2014;9(1):469.
    PMID: 25246872 DOI: 10.1186/1556-276X-9-469
    Hierarchical Si/ZnO trunk-branch nanostructures (NSs) have been synthesized by hot wire assisted chemical vapor deposition method for trunk Si nanowires (NWs) on indium tin oxide (ITO) substrate and followed by the vapor transport condensation (VTC) method for zinc oxide (ZnO) nanorods (NRs) which was laterally grown from each Si nanowires (NWs). A spin coating method has been used for zinc oxide (ZnO) seeding. This method is better compared with other group where they used sputtering method for the same process. The sputtering method only results in the growth of ZnO NRs on top of the Si trunk. Our method shows improvement by having the growth evenly distributed on the lateral sides and caps of the Si trunks, resulting in pine-leave-like NSs. Field emission scanning electron microscope image shows the hierarchical nanostructures resembling the shape of the leaves of pine trees. Single crystalline structure for the ZnO branch grown laterally from the crystalline Si trunk has been identified by using a lattice-resolved transmission electron microscope. A preliminary photoelectrochemical (PEC) cell testing has been setup to characterize the photocurrent of sole array of ZnO NR growth by both hydrothermal-grown (HTG) method and VTC method on ITO substrates. VTC-grown ZnO NRs showed greater photocurrent effect due to its better structural properties. The measured photocurrent was also compared with the array of hierarchical Si/ZnO trunk-branch NSs. The cell with the array of Si/ZnO trunk-branch NSs revealed four-fold magnitude enhancement in photocurrent density compared with the sole array of ZnO NRs obtain from VTC processes.
    Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
  8. Mirjalili F, Chuah L, Salahi E
    ScientificWorldJournal, 2014;2014:718765.
    PMID: 24688421 DOI: 10.1155/2014/718765
    A nanocomposite containing polypropylene (PP) and nano α-Al2O3 particles was prepared using a Haake internal mixer. Mechanical tests, such as tensile and flexural tests, showed that mechanical properties of the composite were enhanced by addition of nano α-Al2O3 particles and dispersant agent to the polymer. Tensile strength was approximately ∼ 16% higher than pure PP by increasing the nano α-Al2O3 loading from 1 to 4 wt% into the PP matrix. The results of flexural analysis indicated that the maximum values of flexural strength and flexural modulus for nanocomposite without dispersant were 50.5 and 1954 MPa and for nanocomposite with dispersant were 55.88 MPa and 2818 MPa, respectively. However, higher concentration of nano α-Al2O3 loading resulted in reduction of those mechanical properties that could be due to agglomeration of nano α-Al2O3 particles. Transmission and scanning electron microscopic observations of the nanocomposites also showed that fracture surface became rougher by increasing the content of filler loading from 1 to 4% wt.
    Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
  9. Antony JJ, Mubbarakh SA, Mahmood M, Subramaniam S
    Appl Biochem Biotechnol, 2014 Feb;172(3):1433-44.
    PMID: 24218184 DOI: 10.1007/s12010-013-0636-x
    Histological observation and scanning electron microscopy analyses in Dendrobium Bobby Messina indicates the cellular process of cryopreserved protocorm-like bodies (PLBs) was different comparative to non-cryopreserved PLBs. The cellular process was not only modified by the freezing and thawing effect but also due to the dehydration process itself during the cryopreservation procedure. Histological observation in Dendrobium Bobby Messina in encapsulation-dehydration method indicated that the degree of plasmolysis causes more cellular changes to the cryopreserved PLBs comparative to non-cryopreserved and stock culture PLBs. These results revealed higher amount of homogenous cell population and denser cytoplasm in cryopreserved PLBs. Histological analysis also revealed more voluminous nucleus in cryopreserved PLBs comparative to non-cryopreserved PLBs and PLBs stock culture. In contrast, scanning electron microscope analysis showed severe damages in cryopreserved PLBs and non-cryopreserved PLBs comparative to the PLBs stock culture which in return could be the possible reason of no regrowth in encapsulation-dehydration method. Damages incurred were on top part, side part, and at the stomata of the PLBs. Histological observation and scanning electron microscopy analyses in Dendrobium Bobby Messina indicates that the degree of plasmolysis causes changes in the cellular process of PLBs from cryopreserved PLBs was different comparative to non-cryopreserved PLBs.
    Matched MeSH terms: Microscopy, Electron, Scanning*
  10. Sim KS, Ting HY, Lai MA, Tso CP
    J Microsc, 2009 Jun;234(3):243-50.
    PMID: 19493101 DOI: 10.1111/j.1365-2818.2009.03167.x
    An improvement to the previously proposed Canny optimization technique for scanning electron microscope image colorization is reported. The additional process is adaptive tuning, where colour tuning is performed adaptively, based on comparing the original luminance values with calculated luminance values. The complete adaptive Canny optimization technique gives significantly better mechanical contrast on scanning electron microscope grey-scale images than do existing methods.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods*
  11. Sim KS, Thong LW, Ting HY, Tso CP
    J Microsc, 2010 Feb;237(2):111-8.
    PMID: 20096041 DOI: 10.1111/j.1365-2818.2009.03325.x
    Interpolation techniques that are used for image magnification to obtain more useful details of the surface such as morphology and mechanical contrast usually rely on the signal information distributed around edges and areas of sharp changes and these signal information can also be used to predict missing details from the sample image. However, many of these interpolation methods tend to smooth or blur out image details around the edges. In the present study, a Lagrange time delay estimation interpolator method is proposed and this method only requires a small filter order and has no noticeable estimation bias. Comparing results with the original scanning electron microscope magnification and results of various other interpolation methods, the Lagrange time delay estimation interpolator is found to be more efficient, more robust and easier to execute.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods*
  12. Haafiz MK, Hassan A, Khalil HP, Fazita MR, Islam MS, Inuwa IM, et al.
    Int J Biol Macromol, 2016 Apr;85:370-8.
    PMID: 26772914 DOI: 10.1016/j.ijbiomac.2016.01.004
    In this work, polylactic acid (PLA) reinforced cellulose nanowhiskers (CNW) were prepared through solution casting technique. The CNW was first isolated from oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC) by using 64% H2SO4 and was designated as CNW-S. The optical microscopy revealed that the large particle of OPEFB-MCC has been broken down by the hydrolysis treatment. The atomic force microscopy confirmed that the CNW-S obtained is in nanoscale dimension and appeared in individual rod-like character. The produced CNW-S was then incorporated with PLA at 1, 3, and 5 parts per hundred (phr) resins for the PLA-CNW-S nanocomposite production. The synthesized nanocomposites were then characterized by a mean of tensile properties and thermal stability. Interestingly to note that incorporating of 3 phr/CNW-S in PLA improved the tensile strength by 61%. Also, CNW-S loading showed a positive impact on the Young's modulus of PLA. The elongation at break (Eb) of nanocomposites, however, decreased with the addition of CNW-S. Field emission scanning electron microscopy and transmission electron microscopy revealed that the CNW-S dispersed well in PLA at lower filler loading before it started to agglomerate at higher CNW-S loading (5phr). The DSC analysis of the nanocomposites obtained showed that Tg,Tcc and Tm values of PLA were improved with CNW-S loading. The TGA analysis however, revealed that incopreated CNW-S in PLA effect the thermal stability (T10,T50 and Tmax) of nanocomposite, where it decrease linearly with CNW-S loading.
    Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
  13. Lazar PJL, Sengottuvelu R, Natarajan E
    Materials (Basel), 2018 Nov 05;11(11).
    PMID: 30400592 DOI: 10.3390/ma11112186
    The principal objective of this research work was to investigate the results of impregnating epoxy matrix-glass fibre composite laminates with nanosilica as secondary reinforcement. 0.5, 0.75, 1 and 3 wt% nanosilica was used and thereafter properties of composites were assessed through tensile, three point bending, quasi static indentation tests and dynamic mechanical analysis. Scanning electron microscope examinations were done on fracture surfaces and failure modes were analyzed. The internal failures of the composite due to quasi-static indentation were evaluated through C-Scan. Among samples of different weight fractions, 0.75 wt% nanosilica reinforced composite laminates exhibited substantial increase of 42% in tensile strength and 39.46% in flexural strength. The reduction in glass transition temperature (Tg), increase in storage modulus (E'), loss modulus (E″) and damping factor (tan δ) were also observed. Quasi-static indentation assessments revealed that energy absorption property was enhanced significantly by 53.97%. Hence nanosilica up to 0.75 wt% can be used as a potential candidate for secondary reinforcement in epoxy composite laminates.
    Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
  14. Mohamad Fahrul Radzi Hanifah, Juhana Jaafar, Madzlan Aziz, Mohd Hafiz Dzarfan Othman, Mukhlis A. Rahman, Ahmad Fauzi Ismail, et al.
    Sains Malaysiana, 2017;46:629-635.
    Reduced graphene oxide nanosheet (RGO)/Pt nanocomposite have been successfully prepared through a facile chemical reduction method. The reduction of Pt precursor was carried out using sodium borohydride as the efficient chemical reductant. The morphology of RGO/Pt nanocomposite was investigated using high resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM). HRTEM analysis showed that platinum nanoparticles were homogenously distributed onto the surface of RGO. The electrochemical study proved that Pt nanoparticles were successfully incorporated onto RGO. Therefore, it can be concluded that the proposed method could provide well-dispersed of Pt nanoparticles onto RGO to form RGO/ Pt nanocomposite.
    Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
  15. Toussi SM, Fakhru’L-Razi A, Luqman Chuah A, Suraya A
    Single-walled carbon nanotubes (SWCNTs) were synthesized by catalytic chemical vapor deposition (CCVD) of ethanol (C2H5OH) over Fe-Mo-MgO catalyst by using argon as a carrier gas. The reaction conditions are important factors that influence the yield and quality of carbon nanotubes. The effects of temperature and flow rate of carrier gas were investigated to increase the yield of carbon nanotubes. The synthesized carbon nanotubes were characterized by scanning electron microscopy, transmission electron microscopy, X-Ray diffraction and thermo-gravimetric analysis. The results showed that the growth of carbon nanotubes was effectively influenced by the reaction ambience and the synthesis condition. The temperature and flow rate of carrier gas played a key role in the yield and quality of synthesized CNTs. The estimated yield of synthesized carbon nanotubes was almost over 70%.
    Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
  16. Sotoodehnia P, Mazlan N, Mohd Saud H, Samsuri WA, Habib SH, Soltangheisi A
    PeerJ, 2019;7:e6418.
    PMID: 30918747 DOI: 10.7717/peerj.6418
    Background: Plant growth-promoting rhizobacteria (PGPR) are highly promising biofertilizers that contribute to eco-friendly sustainable agriculture. There have been many reports on the anti-microbial properties of nanoparticles (NPs). Toxic effects of NPs under laboratory conditions have also reported; however, there is a lack of information about their uptake and mobility in organisms under environmental conditions. There is an urgent need to determine the highest concentration of NPs which is not detrimental for growth and proliferation of PGPR.

    Methods: Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to measure the size and shape of NPs. Minimum inhibitory concentrations (MIC) of nano-silver on selected beneficial microbes and Ralstonia solanacearum were measured using the microdilution broth method. The percentage of seed germination was measured under in vitro conditions.

    Results: NPs were spherical with a size of 16 ± 6 nm. Nano-silver at 12-40 mg l-1 inhibited the growth of bacteria. Seed application at 40 mg l-1 protected seeds from R. solanacearum and improved the rate of seed germination.

    Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
  17. Abdul Khalil HPS, Md. Sohrab Hossain, Nur Amiranajwa AS, Nurul Fazita MR, Mohamad Haafiz MK, Suraya N, et al.
    Sains Malaysiana, 2016;45:833-839.
    This present study was conducted to produce defatted oil palm shell (OPS) nanoparticles. Wherein, the OPS nanoparticles
    were defatted by solvent extraction method. Several analytical methods including transmission electron microscope (TEM),
    X-ray diffraction (XRD), particle size analyzer, scanning electron microscope (SEM), SEM energy dispersive X-ray (SEM-EDX)
    and thermal gravimetric analyzer (TGA) were used to characterize the untreated and defatted OPS nanoparticles. It was
    found that 75.3% OPS particles were converted into nanoparticles during ball milling. The obtained OPS nanoparticles had
    smaller surface area with angular, irregular and crushed shapes under SEM view. The defatted OPS nanoparticles did not
    show any agglomeration during TEM observation. However, the untreated OPS nanoparticles had higher decomposition
    temperature as compared to the defatted OPS nanoparticles. Based on the characterization results of the OPS nanoparticles,
    it is evident that the defatted OPS nanoparticles has the potentiality to be used as filler in biocomposites
    Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
  18. Arafat MM, Haseeb AS, Akbar SA
    Sensors (Basel), 2014;14(8):13613-27.
    PMID: 25072346 DOI: 10.3390/s140813613
    In this research work, the sensitivity of TiO2 nanoparticles towards C2H5OH, H2 and CH4 gases was investigated. The morphology and phase content of the particles was preserved during sensing tests by prior heat treatment of the samples at temperatures as high as 750 °C and 1000 °C. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis were employed to characterize the size, morphology and phase content of the particles. For sensor fabrication, a film of TiO2 was printed on a Au interdigitated alumina substrate. The sensing temperature was varied from 450 °C to 650 °C with varying concentrations of target gases. Results show that the sensor has ultrahigh response towards ethanol (C2H5OH) compared to hydrogen (H2) and methane (CH4). The optimum sensing temperature was found to be 600 °C. The response and recovery times of the sensor are 3 min and 15 min, respectively, for 20 ppm C2H5OH at the optimum operating temperature of 600 °C. It is proposed that the catalytic action of TiO2 with C2H5OH is the reason for the ultrahigh response of the sensor.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods; Microscopy, Electron, Transmission/methods
  19. Lim J, Yeap SP, Che HX, Low SC
    Nanoscale Res Lett, 2013;8(1):381.
    PMID: 24011350 DOI: 10.1186/1556-276X-8-381
    Here we provide a complete review on the use of dynamic light scattering (DLS) to study the size distribution and colloidal stability of magnetic nanoparticles (MNPs). The mathematical analysis involved in obtaining size information from the correlation function and the calculation of Z-average are introduced. Contributions from various variables, such as surface coating, size differences, and concentration of particles, are elaborated within the context of measurement data. Comparison with other sizing techniques, such as transmission electron microscopy and dark-field microscopy, revealed both the advantages and disadvantages of DLS in measuring the size of magnetic nanoparticles. The self-assembly process of MNP with anisotropic structure can also be monitored effectively by DLS.
    Matched MeSH terms: Microscopy, Electron, Transmission
  20. Ahmad P, Khandaker MU, Amin YM, Muhammad N
    Sci Rep, 2016;6:21403.
    PMID: 26892366 DOI: 10.1038/srep21403
    Boron niride microflakes of 2-5 μm in diameter and greater than 40 μm in length with multilayer structure and highly crystalline nature are synthesized in two states of catalysts and dual role of nitrogen at 1100 °C. Most of the microflakes are flat, smooth and vertically aligned with a wall-like view from the top. Transmission electron microscopy shows overlapped layers of microflakes with an interlayer spacing of 0.34 nm. The h-BN components of the synthesized microflakes are verified from B 1s and N1 s peaks at 190. 7 and 397.9 eV. Raman shift at 1370 (cm(-1)) and sharp peaks in the XRD pattern further confirm the h-BN phase and crystalline nature of the synthesized microflakes. Microflakes of h-BN with the above characteristics are highly desirable for the development of a solid state neutron detector with higher detection efficiency.
    Matched MeSH terms: Microscopy, Electron, Transmission
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