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  • 1
    Electronic Resource
    Electronic Resource
    Adsorption of benzene on porous amorphous hydrogenated carbon films (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 3806-3811 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The annealing effect on porosity of amorphous hydrogenerated carbon thin films was studied using a quartz crystal microbalance. As-prepared films show a mesoporous structure and a low adsorption capacity which is proportional to film thickness. Porosity of the as-prepared film is estimated at about 0.15. Baking in vacuum changes the film to be highly microporous and significantly increases the porosity of the films to over 0.40, depending annealing history. Outgassing during the annealing process plays an important role in the formation of porosity. Heat treatment first opens micropores in the slightly mesoporous film. Further heating increases the number and size of micropores, and also produces mesopores. With prolonged heating at high temperatures, further outgassing occurs, resulting in collapsing of the films.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350894
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  • 2
    Electronic Resource
    Electronic Resource
    TRIUMF injection line nonintercepting beam energy monitoring through phase measurement : Proceedings of the 6th international conference on ion sources (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 1255-1257 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A nonintercepting beam velocity monitoring system has been installed in the 300 keV injection line of the TRIUMF cyclotron to reproduce the injection energy for different ion source beams and monitor any beam energy fluctuations. The monitor is tuned to resonate at 46 MHz and is 3.25 m downstream from the first 23 MHz buncher. The phase difference between the first buncher and the pickup is related to the average beam velocity, i.e., beam energy. The energy sensitivity of the measurement is 1×10−4. The dynamic range of the monitor with beam current is 60 dB, and the measured instantaneous beam intensity can go down to 100 nA. The theory behind the device and the results of beam tests will be described. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146690
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  • 3
    Electronic Resource
    Electronic Resource
    Relationship Between Mammographic Breast Density and Tamoxifen in Women with Breast Cancer (2004)
    Oxford, UK : Blackwell Science Inc
    The @breast journal 10 (2004), S. 0 
    Details
    ISSN: 1524-4741
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract:  Previous studies have reported that tamoxifen use is associated with a decrease in mammographic breast density. This is a potentially valuable finding since mammographic sensitivity is limited by breast density. Anything that reduces breast density would theoretically enhance the sensitivity of mammography for the detection of breast cancer in women at an earlier stage when it is more curable. We performed a retrospective study investigating the potential effect of tamoxifen on breast density. The data for this retrospective study were collected from the records of 52 charts from a single medical oncologist. Patients with breast cancer were selected regardless of stage or age at the time of diagnosis or treatment, as long as their charts had records of bilateral mammograms. For each breast on each woman, both mediolateral oblique and craniocaudal views were reviewed independently by two radiologists on two separate occasions to obtain inter- and intraobserver variability. Two methods of classifying breast density were used: the Breast Imaging Reporting and Data System (BI-RADS), and measurements of percent density. Only age and menopausal status were found to be associated with breast density. There was no correlation between breast density and tamoxifen use (past or present). Our study shows no association between tamoxifen use and breast density. We confirm previous observations that breast density is inversely correlated with age and postmenopausal status. 
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1075-122X.2004.21332.x
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  • 4
    Electronic Resource
    Electronic Resource
    Properties of TiN films deposited at low temperature in a new plasma-based deposition system (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 6279-6285 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Stoichiometric titanium nitride (TiN) films were deposited at less than 130 °C in a new configuration of the helicon activated reactive evaporation system. An in situ ellipsometer was used to monitor the optical properties of the films during growth. The film stress, lattice parameter, surface roughness, crystallite size, and preferred orientation were investigated as a function of substrate bias and hence ion energy of the incident species. The intrinsic stress dependence on ion energy shows the expected result also shown by a variety of materials and is in good agreement with the theoretical model of Davis [Thin Solid Films 226, 30 (1993)]. The high stress level at −50 V bias is confirmed by measurement of lattice parameter. X-ray-diffraction measurements show that the (111)-preferred orientation normal to the substrate surface correlates strongly with the stress level of the films. By correlating our results with those from a number of other reported studies at higher substrate temperature we conclude that the observed preferred orientation in TiN films can be explained from the viewpoint of the energy minimization principle. Kinetic factors are of less importance except possibly at the highest bombardment energies. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363704
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  • 5
    Electronic Resource
    Electronic Resource
    The application of the cathodic arc to plasma assisted chemical vapor deposition of carbon (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 1563-1568 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This article reports on the properties of hydrogenated carbon films deposited using a cathodic arc decomposition process with a graphite cathode used in a plasma assisted chemical vapor deposition mode. In this application of the cathodic arc, acetylene is broken down into radicals to form hydrogenated amorphous carbon films. Some results are also reported using hydrogen gas. The density in terms of plasmon energy or sp3 fraction of the films has been found to decrease with increasing acetylene or hydrogen flow rate, approaching the value for glow discharge deposited polymer-like hydrogenated amorphous carbon. When substrate bias is used, the hydrogen content is reduced and graphite microcrystals appear, together with cauliflower-like growths. In the range between 100 and 500 V, negative substrate bias increases the density of the films. Overall, the hydrogen content decreases with the density of the films. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362649
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  • 6
    Electronic Resource
    Electronic Resource
    Structural investigation of two carbon nitride solids produced by cathodic arc deposition and nitrogen implantation (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 6914-6919 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Carbon nitride materials have been the focus of research efforts worldwide. Most materials studied have been amorphous, with only a few groups claiming to have found a crystalline material. We investigate the structure of amorphous carbon nitride solids produced by two different techniques: cathodic arc deposition and high dose nitrogen implantation of glassy carbon. Transmission electron microscopy, electron energy loss spectroscopy, energy filtered electron diffraction, Rutherford backscattering, infrared, and Raman spectroscopy are all used to derive structural information. It was found that the carbon nitride materials prepared by both techniques have similar structures and [N]/[C] ratios (0.3). The materials appear to have a primarily sp2 bonded carbon structure with a smaller bond length than found in amorphous carbon. This is explained by nitrogen substituting into "rings'' to a saturation level of about one nitrogen per three carbon atoms. We have found no evidence for a C3N4 crystalline structure, nor any amorphous derivative of it. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.361515
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  • 7
    Electronic Resource
    Electronic Resource
    Optimization and analysis of solar selective surfaces with continuous and multilayer profiles (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 6485-6491 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Both continuous and multilayer profiles of solar selective surfaces have been analyzed and optimized. The structure having the highest photothermal efficiency has two uniform absorbing layers with two antireflection layers of different refractive index materials. Interference effects were analyzed in terms of optical path length of the sublayers and their combination. The phase cancellation positions for the optimized multilayer profiles are well distributed in the solar radiation range but do not occur at wavelengths above about 2.5 μm. A study of the electric-field distribution in these optimized profiles has shown that the sharp transition at above about 2.5 μm from low to high reflectance is due to the absence of high filling factor sublayers which can act as an effective reflecting substrate. The selective properties of the optimized multilayer structures are not particularly sensitive to the optimized graded profile for thickness variations of ±20%. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359124
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  • 8
    Electronic Resource
    Electronic Resource
    Highly tetrahedral amorphous carbon films with low stress (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 2344-2346 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have deposited boronated highly tetrahedral amorphous carbon (ta-C:B) films with low stress using a filtered cathodic vacuum arc. The sp3 fraction, hardness, and resistivity were measured as a function of the ion energy and were found to reach a maximum above 50 eV for B concentrations of 2% and 4%. The most significant result we found was that highly tetrahedral a-C:B film (sp3≈80%) with low stress (1–3 GPa) with B concentrations up to 4% could be obtained. The B in the films was found to be predominantly (≈75%) sp2 bonded. Additionally, the stress in the films did not vary with the ion energy or sp3 fraction unlike in regular ta-C films. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.117519
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  • 9
    Electronic Resource
    Electronic Resource
    Negative transconductance in a resistive gate metal-semiconductor field-effect transistor (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1884-1886 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Negative transconductance is reported in a resistive gate metal-semiconductor field-effect transistor (MESFET) for the first time. The negative transconductance arises as a result of the negative differential mobility of electrons in the GaAs channel, and is adequately described by a simple equivalent circuit model. The experimental device is fabricated with a planar ion-implanted MESFET process, and shows promise as a microwave signal source for use in monolithic microwave integrated circuits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101230
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  • 10
    Electronic Resource
    Electronic Resource
    Design of a parallel-plate energy spread analyzer : Proceedings of the 7th international conference on ion sources (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 1194-1196 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A 45° parallel-plate energy spread analyzer has been designed and built for the ISAC project at TRIUMF. It features an energy resolution of ≤0.04% and a spectrometer constant of k=1.29. Nineteen 0.1 mm by 10 mm metal guard frames with 1 MΩ resistors are used to equalize the electric field in the analyzer to an order of ≤0.5%. Electric field simulation is done by a code POISSON. This article describes the design of the analyzer. Preliminary experimental results are also presented. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148663
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