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  • 1
    Electronic Resource
    Electronic Resource
    Effects of local ambient atmosphere on the stability of electroluminescent porous silicon diodes (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 5936-5941 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this work, the influence of surrounding ambient atmosphere on the stability of electroluminescent (EL) porous Si (PS) diodes is examined. We have fabricated electroluminescent porous Si layers from anodic oxidation of (1) epitaxially grown p-type layers on n-type Si substrates; (2) n-type substrates with Au/Pd contacts; (3) p-type substrates with Au/Pd contacts. These structures are characterized using photoluminescence (PL), EL, and infrared (IR) spectroscopies, as well as scanning electron microscopy (SEM). In the case of the porous Si structures fabricated from p-n junctions, such structures yield orange emission with maxima near 620 nm upon the application of moderate applied voltages (3–7 V). For each type of diode, it is found that in strong oxidizing environments, EL intensity degrades completely within 30 min; in contrast, the integrated intensity remains essentially unchanged in the same time frame in the presence of a vigorous flow of inert gases such as nitrogen and argon. Infrared spectroscopic studies strongly suggest that electroluminescence degradation is related to porous silicon surface oxidation. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359550
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  • 2
    Electronic Resource
    Electronic Resource
    Surface reactivity of luminescent porous silicon (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 2094-2096 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of addition of a series of organoamine molecules on the luminescence of porous silicon has been examined by steady-state photoluminescence (PL) and Fourier transform infrared spectroscopies. These samples, prepared nonanodically via stain etching techniques and characterized by atomic force microscopy, show dramatic quenching of visible PL upon addition of dilute solutions of the above Lewis base adsorbates. The fractional changes in integrated PL intensity as a function of quencher concentration obey a simple equilibrium model, demonstrating Langmuir-type behavior from which equilibrium constants can be calculated. An observation concomitant with this loss of PL is a diminution of the silicon hydride stretching frequencies near 2100 cm−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354754
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  • 3
    Electronic Resource
    Electronic Resource
    Formation of rare-earth oxide doped silicon by spark processing (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 3416-3418 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this work, we report a method for the incorporation of rare-earth oxides onto silicon surfaces. This process uses a high-energy dc spark to convert salts of rare-earth ions such as europium and erbium to the corresponding oxide phase(s) with concomitant formation of a porous layer. Scanning electron micrographs of the silicon substrate show an irregular, pitted surface morphology for those areas exposed to spark processing. Photoluminescence, infrared spectroscopy, and electron microscopy of the spark-processed regions of the Si substrate are clearly consistent with the formation of the desired luminescent oxide phase. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115778
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  • 4
    Electronic Resource
    Electronic Resource
    Low field magnetic resonance images of polarized noble gases obtained with a dc superconducting quantum interference device (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 72 (1998), S. 1908-1910 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Using a low transition temperature superconducting quantum interference device as a detector, we have obtained magnetic resonance images of laser-polarized 3He gas and solid 129Xe at 4.2 K in magnetic fields as low as 0.54 mT (3He) and 1 mT (129Xe), corresponding to Larmor frequencies of 17.6 and 11.8 kHz, respectively. The experimental resolution of the images is ∼500 μm for 3He in the gas phase and ∼950 μm for 129Xe in the solid state. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.121223
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  • 5
    Electronic Resource
    Electronic Resource
    Size control of erbium-doped silicon nanocrystals (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 1635-1637 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This work describes the effects of pyrolysis oven length and erbium precursor on the preparation of discrete erbium-doped silicon nanoparticles. These doped nanoparticles were prepared by the co-pyrolysis of disilane and the volatile complex Er(tmhd)3 (tmhd=2,2,6,6-tetramethyl-3,5-heptanedionato). The particle sizes and size distributions were determined using high resolution and conventional transmission electron microscopy. Erbium-doped silicon nanoparticles exhibit a selected area electron diffraction pattern consistent with the diamond cubic phase and a distinctive dark contrast in the transmission electron microscope. The presence of erbium is confirmed by x-ray energy dispersive spectroscopy. In general, the mean diameter of the individual nanoparticles increases as the length of the pyrolysis oven used during their preparation is increased. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1309022
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  • 6
    Electronic Resource
    Electronic Resource
    Mitochondrial uncoupling agents (1975)
    Springer
    The journal of membrane biology 25 (1975), S. 361-380 
    Details
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Agents which uncouple oxidative phosphorylation in mitochondria were applied to identified neurons in an isolated ganglion of the marine molluscNavanax inermis. Aromatic monocarboxylic acids, acetanilides, benzamides, benzaldehydes and phenols all caused a rapid, reversible, dose-dependent increase in the membrane potential and conductance of the neurons tested. These events were due primarily to an increase in the membrane's conductance to potassium, relative to chloride. All active compounds also produced a reversible, dose-dependent decrease in the permeability of alkali-cations relative to potassium. The relative activity of congeners in each group of substances was directly correlated with the octanol-water partition coefficients of the various compounds, indicating that hydrophobicity was important in determining drug effect and suggesting that steric requirements were minimal. The results suggest that the observed changes in membrane electrical properties and cation selectivity are due to an increase in the membrane's anionic field strength caused by the hydrophobic interaction of anionic and nonionic agents with the neuronal membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01868584
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  • 7
    Electronic Resource
    Electronic Resource
    Analysis of the parsley chalcone-synthase promoter in response to different light qualities (1994)
    Springer
    Planta 193 (1994), S. 275-282 
    Details
    ISSN: 1432-2048
    Keywords: Chalcone synthase ; Footprinting in vivo ; Gene expression (transient) ; Light regulation (UV-B photoreceptor, blue-light photoreceptor) ; Petroselinum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We examined the chalcone synthase (chs) promoter from parsley [Petroselinum crispum Miller (A.W. Hill)] for the existence of separate promoter elements responsible for transcriptional activation of the chs gene by UV-B and by blue light. A combination of in-vivo footprinting in parsley cells and light-induced transient expression assays with different chs promoter constructs in parsley protoplasts was used. Dark controls and bluelight-irradiated cells gave identical in-vivo footprints on the chs promoter. Pre-irradiation with blue light prior to a UV-B-light pulse is known to cause a shift in the timing of UV-B-light-induced increase in chs transcription rates. This shift was also manifested on the DNA template, since UV-B-light-induced in-vivo footprints in cells pretreated with blue light were detected earlier than in cells which had been irradiated with a UV-B-light pulse only. Although there was a clear shift in the timing of footprint appearance, the patterns of footprinting did not change. Light-induced transient-expression assays revealed that the shortest tested chs promoter which retained any light responsiveness, was sufficient for mediating both induction by UV light and the blue-light-mediated kinetic shift. These findings argue against a spatial separation of UV-B- and blue-light-responsive elements on the chs promoter. We interpret these data by postulating that the signal transduction pathways originating from the excitation of UV-B- and blue-light receptors merge at the chs promoter, or somewhere between light perception and protein-DNA interaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192541
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  • 8
    Electronic Resource
    Electronic Resource
    Approaches for Generating Mesoscale Patterns of Semiconductor Nanoclusters (1997)
    Springer
    Journal of cluster science 8 (1997), S. 159-178 
    Details
    ISSN: 1572-8862
    Keywords: Mesoscale patterns ; cadmium selenide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract In this review, existing approaches for the manipulation and/or construction of isolated semiconductor nanoclusters into deliberate, patterned arrays are described. Diverse examples of different strategies from solid state, solution, and hybrid combinations are described as well as successes achieved to date. The approaches to be discussed include conventional solid state lithography, volumetric constriction of monodisperse nanoclusters deposited from solution, and the use of anchored macromolecular templates to direct semiconductor nanocluster assembly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022679923799
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  • 9
    Electronic Resource
    Electronic Resource
    Foreword (1989)
    Springer
    Annals of operations research 20 (1989), S. XIII 
    Details
    ISSN: 1572-9338
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02216921
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  • 10
    Electronic Resource
    Electronic Resource
    Porosified Silicon Wafer Structures Impregnated With Platinum Anti-Tumor Compounds: Fabrication, Characterization, and Diffusion Studies (2000)
    Springer
    Biomedical microdevices 2 (2000), S. 265-272 
    Details
    ISSN: 1572-8781
    Keywords: porous silicon ; cis-platin ; drug delivery ; calcium phosphate ; carbo-platin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract In this work, the incorporation and characterization of cis-platin (cis-diammine dichloroplatinum(II)), carbo-platin [cis-diammine(cyclobutane-1,1-dicarboxylato] platinum(II)), and Pt(en)Cl2 (ethylenediamminedichloro platinum(II)) within layers of calcium phosphate on porous Si/Si substrates are described. These materials have been characterized by scanning electron microscopy, secondary ion mass spectrometry, and X-ray energy dispersive spectroscopy. The diffusion of platinum species from the doped calcium phosphate layers has also been investigated by UV-visible absorption spectrometry and inductively-coupled plasma spectroscopy. The influence of initial platinum concentration, the impact of thermal annealing of the calcium phosphate/porous Si/Si matrix, as well as the effect of varying the ligand coordination sphere of the Pt complex on its ability to be delivered to the surroundings have also been analyzed. For the case of cis-platin, it is found that increasing the concentration of platinum complex in the electrolyte during cathodic growth of calcium phosphate results in a relatively greater concentration of Pt incorporated into the calcium phosphate layers and a larger amount of Pt which subsequently can be delivered to the surrounding medium upon exposure to solvent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009951121205
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