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  • 1
    Electronic Resource
    Electronic Resource
    Optical and Surface Morphological Study of GaN Nanocolumn Grown on Gallium Coated Si by Molecular Beam Epitaxy (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 31 (Nov. 2007), p. 120-122 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Vertically aligned GaN nanocolumn arrays were grown by molecular beam epitaxy onGallium coated silicon substrate. The dense packing of the NCs gives them the appearance of acontinuous film in surface view, but cross-sectional analysis shows them to be isolatednanostructures. The GaN nanocolumns have uniform diameters of 85 nm, lengths up to 720 nm andpossess a pyramid like tip. Photoluminescence measurements of NCs show excitonic emission witha dominant, narrow peak centered at 363 nm and FWHM of 68 meV. From the Raman spectrum,peaks at 566.9 and 730 cm-1 are assigned to the E2 and A1(LO) GaN phonons modes which clearlyindicates that the grown nanocolumns are highly crystalline. The grown nanocolumns are highlyoriented and perpendicular to the growth surface
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.31.120.pdf
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  • 2
    Electronic Resource
    Electronic Resource
    Growth of GaN Nano-Column on Si (111) Substrate Using Au+Ga Alloy Seeding by Pulsed Flow Method Using MOCVD (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 31 (Nov. 2007), p. 108-110 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Vertical GaN nano-columns arrays were grown on Au-coated silicon (111) substrate byAu+Ga alloy seeding method and pulsed flow of Gallium and ammonia using metalorganicchemical vapor deposition (MOCVD). A gold thin film was deposited on Si using an ion coatingsystem. The Au coated Si substrate was annealed at 800 oC under hydrogen ambient for 5 min. Thepre-deposition of gallium and nitrogen was performed for 60 sec to form Au+Ga and nitrogen solidsolution, which acts as the initial nucleation islands. Then Gallium and ammonia were let in pulsemethod. Scanning electron microscopy (SEM) image reveals a vertical growth and cylindrical inshape GaN nano-column. From the sharp PL peak intensity it is clearly seen that the dislocationdensity is reduced considerably and the optical quality of the nano-column is improved
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.31.108.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    Growth and Evaluation of GaN Grown on Patterned Sapphire Substrates (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 29-30 (Nov. 2007), p. 351-354 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: We report the microstructure and optical properties of gallium nitride (GaN) epilayersgrown on lens shape patterned sapphire substrate (PSS) using metalorganic chemical vapordeposition (MOCVD) for various growth times. A lens shaped pattern was used to reduce thethreading dislocation density and to improve optical emission efficiency. A scanning electronmicroscope (SEM) image shows flat and smooth surface of GaN grown on PSS at 80 min which couldbe achieved by lateral growth from the trench region. From the DCXRD spectra, full width at halfmaximun (FWHM) value was decreased with increasing growth time. FWHM of the sample grown at80 min was 473.5 arc sec. This indicates there is an improvement in crystalline quality of the GaNgrown on PSS as the growth time increases. From photoluminescence (PL) spectra, an increase inband edge emission intensity and a decrease in defect related yellow luminescence was observed forGaN on PSS as the growth time increased. From the PL spectra, FWHM was 82.2 meV at peakposition 363.9 nm for the sample grown for 80 min. It is clearly seen that the threading dislocationscan be reduced by lateral growth improving the light emission efficiency by internal light reflection onthe lens surface for GaN grown on PSS
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.29-30.351.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    Characteristics Comparison between GaN Epilayers Grown on Patterned and Unpatterned Sapphire Substrate (0001) (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 29-30 (Nov. 2007), p. 355-358 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: GaN epilayers were grown on lens shaped patterned sapphire substrate (PSS) (0001) andunpatterned sapphire substrate (UPSS) (0001) by metal-organic chemical vapor deposition(MOCVD). The quality of the grown GaN epilayers on the PSS and UPSS were compared. Structuralcharacteristics, surface morphology and optical properties of the GaN epilayers were investigatedusing double crystal X-ray diffraction (DCXRD), atomic force microscopy (AFM), scanning electronmicroscopy (SEM) and photoluminescence (PL). A lens shaped pattern was formed on the sapphiresubstrate to reduce threading dislocation (TD) density and also to improve the optical emissionefficiency by internal reflection on the lens. Scanning electron microscopy images show the growth ofGaN epilayers at various times. Full coalescence is observed at a growth time of 80 min. It is seenfrom the DCXRD rocking spectrum that full width at half maximum (FWHM) of the GaN grown onPSS was 438.7 arcsec which is less than UPSS value. The lower value of FWHM indicates that thecrystalline quality of the GaN epilayers grown on PSS is improved compared to GaN grown on UPSS.It is clearly seen from the AFM images that the dislocation density is less for the GaN grown on PSS.A strong and sharp photoluminescence (PL) band edge emission was observed for the GaN grown onPSS compared to UPSS. Defect related yellow luminescence was observed for GaN grown on UPSSwhich did not appear for PSS. The FWHM at the 364.3 nm peak position was evaluated to be 50.7meV from the PL spectra for GaN grown on PSS. The above result indicates GaN epilayers can begrown on PSS with low TD density and will be useful for optical emission
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.29-30.355.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    Raman study of Epitaxial lateral Overgrowth of GaN on Patterned Sapphire Substrate (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 31 (Nov. 2007), p. 111-113 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Structural and optical properties of gallium nitride (GaN) epilayers grown on lens shapepatterned sapphire substrate (PSS) using metalorganic chemical vapor deposition (MOCVD) forvarious growth times were evaluated. From Raman spectra, a blue shift and reduction in the FWHMof Raman modes of GaN grown on PSS were observed when compared to GaN grown onunpatterend sapphire substrate (UPSS). From the DCXRD spectra, full width at half maximum(FWHM) value was decreased with increasing growth time. FWHM of the sample grown at 80 minwas 473.5 arc sec. This indicates that there is an improvement in crystalline quality of the GaNgrown on PSS as the growth time increases. From photoluminescence (PL) spectra, an increase inband edge emission intensity and a decrease in defect related yellow luminescence were observedfor GaN on PSS as the growth time increased
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.31.111.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    Catalase Activity for Rapid Assessment of High Level Total Mesophilic Microbial Load in Milk (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 67 (2002), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: : Total mesophilic microbial load (APC) is an important index for milk quality. It takes 48 h to enumerate APC with conventional plating methods. This report presents a rapid catalase activity test for monitoring APC in milk. Most aerobic microorganisms have strong catalase activities. Catalase activity in milk was monitored with a Pasteur pipette method in 5 min. The correlation between high APC numbers (〉 4.0 log CFU/ml) and catalase activities was strongly correlated with r2=0.89. Classifying the APC into eight contamination groups was found to be a sound means of utilizing the resultant catalase activities to predict APC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.2002.tb08732.x
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  • 7
    Electronic Resource
    Electronic Resource
    A modified method for studying the interaction of isolated cardiac cell membrane with ions and drugs
    Amsterdam : Elsevier
    Analytical Biochemistry 75 (1976), S. 345-355 
    Details
    ISSN: 0003-2697
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0003-2697(76)90088-9
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  • 8
    Electronic Resource
    Electronic Resource
    EVALUATION OF THIN AGAR LAYER METHOD FOR RECOVERY OF COLD-INJURED FOODBORNE PATHOGENS (2001)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of rapid methods and automation in microbiology 9 (2001), S. 0 
    Details
    ISSN: 1745-4581
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The thin agar layer (TAL) method was used to enumerate cold-injured (-20C for 2 h and then 25C for 2 h) foodborne pathogens. This method involves overlaying 14 mL of nonselective medium (Tryptic Soy Agar, TSA) onto a prepoured, pathogen-specific, selective medium. The microbial recovery with the TAL method was compared with the recovery for TSA and pathogen-specific, selective media. No significant difference occurred between TSA and TAL (P〈 0.05) for enumeration of cold-injured Listeria monocytogenes, Salmonella typhimurium, and Yersinia enterocolitica, and they recovered significantly higher numbers than selective media (P〈0.05). No statistical differences occurred among TSA, TAL, and selective media (P〉0.05) for recovery of cold-injured Escherichia coli O157:H7 and Staphyococcus aureus, but the numbers of cells recovered were lower in selective media than TSA or TAL. The TAL method has better recovery capacity than selective media and provides better selectivity than TSA to differentiate target microorganisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4581.2001.tb00224.x
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  • 9
    Electronic Resource
    Electronic Resource
    ESTIMATION OF MICROBIOLOGICAL QUALITY OF EGG USING CHROMOGENIC LIMULUS AMOEBOCYTE LYSATE ENDPOINT ASSAY (2005)
    Oxford, UK : Blackwell Science Inc
    Journal of rapid methods and automation in microbiology 13 (2005), S. 0 
    Details
    ISSN: 1745-4581
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Gram-negative microorganisms, including Pseudomonas and Aeromonas, are widely implicated in the spoilage of liquid egg products. The ratio of gram-negative to gram-positive organisms in egg is essentially constant, and the aerobic plate count (APC) gives a good indication of the overall microbiological quality of egg. However, this method requires 5 days to complete, which limits its practical application. Our objective was to determine whether the rapid chromogenic Limulus amoebocyte lysate (LAL) assay could be applied to assess the microbiological quality of eggs. A modified LAL (BioWhittaker, Inc., Walkersville, MD) procedure was compared with the APC. LAL values were plotted against conventional plate counts, and a strong correlation (R2 = 0.93; n = 40) was observed. Subsequent experiments showed that LAL values allow an accurate prediction of APC (R2 = 0.81; n = 50). These results indicate that the LAL assay is a viable alternative to APC for the estimation of the microbial load in egg, requiring just 16 min to complete.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4581.2005.00004.x
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  • 10
    Electronic Resource
    Electronic Resource
    MINIATURIZED TWO-FOLD DILUTION METHOD FOR ENUMERATING TOTAL MICROBIAL LOAD AND COLIFORMS IN RAW MILK (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of rapid methods and automation in microbiology 10 (2002), S. 0 
    Details
    ISSN: 1745-4581
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A rapid and simple method for enumerating total aerobic plate counts (APC) and coliforms in raw milk was developed and compared with conventional plating method. Following two-fold serial dilution of samples in a 96 well microtiter plate, double strength of two different modified media for APC or coliforms was added to each well. The final positive well (purple to yellow color) was determined and converted to dilution factors. The dilution factor of each sample was converted to Log10 DF (Dilution factors) and compared to actual microbial numbers Log10 CFU/mL. The results of 2-fold dilution method (Log10 DF) were strongly correlated to conventional plating method (Log10 CFU/mL) (P 〈 0.05). The correlation of the scatterplot of spread plating and 2-fold dilution method indicated a high level of agreement between two methods (R2= 0.921 for total counts and R2= 0.916 for forms from raw milk). This 2-fold dilution method is an easy, rapid, and economical method for enumeration of total microbial loads and coliforms in raw milk.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4581.2002.tb00006.x
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