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Sample records for beam surface analysis

  1. Ion beam analysis of metal ion implanted surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Evans, P.J.; Chu, J.W.; Johnson, E.P.; Noorman, J.T. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Sood, D.K. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    Ion implantation is an established method for altering the surface properties of many materials. While a variety of analytical techniques are available for the characterisation of implanted surfaces, those based on particle accelerators such as Rutherford backscattering (RBS) and nuclear reaction analysis (NRA) provide some of the most useful and powerful for this purpose. Application of the latter techniques to metal ion implantation research at ANSTO will be described with particular reference to specific examples from recent studies. Where possible, the information obtained from ion beam analysis will be compared with that derived from other techniques such as Energy Dispersive X-ray (EDX) and Auger spectroscopies. 4 refs., 5 figs.

  2. Surface Science Analysis of GaAs Photocathodes Following Sustained Electron Beam Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Shutthanandan, V.; Zhu, Zihua; Stutzman, Marcy L.; Hannon, Fay; Hernandez-Garcia, Carlos; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T; Thevuthasan, Suntharampillai; Hess, Wayne P.

    2012-06-12

    Degradation of the photocathode materials employed in photoinjectors represents a challenge for sustained operation of nuclear physics accelerators and high power Free Electron Lasers (FEL). Several photocathode degradation processes are suspected, including defect formation by ion back bombardment, photochemistry of surface adsorbed species and irradiation-induced surface defect formation. To better understand the mechanisms of photocathode degradation, we have conducted surface and bulk analysis studies of two GaAs photocathodes removed from the FEL photoinjector after delivering electron beam for a few years. The analysis techniques include Helium Ion Microscopy (HIM), Rutherford Backscattering Spectrometry (RBS), Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS). In addition, strained super-lattice GaAs photocathode samples, removed from the CEBAF photoinjector were analyzed using Transmission Electron Microscopy (TEM) and SIMS. This analysis of photocathode degradation during nominal photoinjector operating conditions represents first steps towards developing robust new photocathode designs necessary for generating sub-micron emittance electron beams required for both fourth generation light sources and intense polarized CW electron beams for nuclear and high energy physics facilities.

  3. Surface science analysis of GaAs photocathodes following sustained electron beam delivery

    Energy Technology Data Exchange (ETDEWEB)

    Carlos Hernandez-Garcia, Fay Hannon, Marcy Stutzman, V. Shutthanandan, Z. Zhu, M. Nandasri, S. V. Kuchibhatla, S. Thevuthasan, W. P. Hess

    2012-06-01

    Degradation of the photocathode materials employed in photoinjectors represents a challenge for sustained operation of nuclear physics accelerators and high power Free Electron Lasers (FEL). Photocathode quantum efficiency (QE) degradation is due to residual gasses in the electron source vacuum system being ionized and accelerated back to the photocathode. These investigations are a first attempt to characterize the nature of the photocathode degradation, and employ multiple surface and bulk analysis techniques to investigate damage mechanisms including sputtering of the Cs-oxidant surface monolayer, other surface chemistry effects, and ion implantation. Surface and bulk analysis studies were conducted on two GaAs photocathodes, which were removed from the JLab FEL DC photoemission gun after delivering electron beam, and two control samples. The analysis techniques include Helium Ion Microscopy (HIM), Rutherford Backscattering Spectrometry (RBS), Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS). In addition, two high-polarization strained superlattice GaAs photocathode samples, one removed from the Continuous Electron Beam Accelerator Facility (CEBAF) photoinjector and one unused, were also analyzed using Transmission Electron Microscopy (TEM) and SIMS. It was found that heat cleaning the FEL GaAs wafer introduces surface roughness, which seems to be reduced by prolonged use. The bulk GaAs samples retained a fairly well organized crystalline structure after delivering beam but shows evidence of Cs depletion on the surface. Within the precision of the SIMS and RBS measurements the data showed no indication of hydrogen implantation or lattice damage from ion back bombardment in the bulk GaAs wafers. In contrast, SIMS and TEM measurements of the strained superlattice photocathode show clear crystal damage in the wafer from ion back bombardment.

  4. Surface science analysis of GaAs photocathodes following sustained electron beam delivery

    Directory of Open Access Journals (Sweden)

    V. Shutthanandan

    2012-06-01

    Full Text Available Degradation of the photocathode materials employed in photoinjectors represents a challenge for sustained operation of nuclear physics accelerators and high power free electron lasers (FEL. Photocathode quantum efficiency degradation is due to residual gases in the electron source vacuum system being ionized and accelerated back to the photocathode. These investigations are a first attempt to characterize the nature of the photocathode degradation, and employ multiple surface and bulk analysis techniques to investigate damage mechanisms including sputtering of the Cs-oxidant surface monolayer, other surface chemistry effects, and ion implantation. Surface and bulk analysis studies were conducted on two GaAs photocathodes, which were removed from the JLab FEL DC photoemission gun after delivering electron beam, and two control samples. The analysis techniques include helium ion microscopy, Rutherford backscattering spectrometry (RBS, atomic force microscopy, and secondary ion mass spectrometry (SIMS. In addition, two high-polarization strained superlattice GaAs photocathode samples, one removed from the continuous electron beam accelerator facility (CEBAF photoinjector and one unused, were also analyzed using transmission electron microscopy (TEM and SIMS. It was found that heat cleaning the FEL GaAs wafer introduces surface roughness, which seems to be reduced by prolonged use. The bulk GaAs samples retained a fairly well organized crystalline structure after delivering beam but show evidence of Cs depletion on the surface. Within the precision of the SIMS and RBS measurements, the data showed no indication of hydrogen implantation or lattice damage from ion back bombardment in the bulk GaAs wafers. In contrast, SIMS and TEM measurements of the strained superlattice photocathode show clear crystal damage in the wafer from ion back bombardment.

  5. Surface science analysis of GaAs photocathodes following sustained electron beam delivery

    Energy Technology Data Exchange (ETDEWEB)

    Carlos Hernandez-Garcia, Fay Hannon, Marcy Stutzman, V. Shutthanandan, Z. Zhu, M. Nandasri, S. V. Kuchibhatla, S. Thevuthasan, W. P. Hess

    2012-06-01

    Degradation of the photocathode materials employed in photoinjectors represents a challenge for sustained operation of nuclear physics accelerators and high power Free Electron Lasers (FEL). Photocathode quantum efficiency (QE) degradation is due to residual gasses in the electron source vacuum system being ionized and accelerated back to the photocathode. These investigations are a first attempt to characterize the nature of the photocathode degradation, and employ multiple surface and bulk analysis techniques to investigate damage mechanisms including sputtering of the Cs-oxidant surface monolayer, other surface chemistry effects, and ion implantation. Surface and bulk analysis studies were conducted on two GaAs photocathodes, which were removed from the JLab FEL DC photoemission gun after delivering electron beam, and two control samples. The analysis techniques include Helium Ion Microscopy (HIM), Rutherford Backscattering Spectrometry (RBS), Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS). In addition, two high-polarization strained superlattice GaAs photocathode samples, one removed from the Continuous Electron Beam Accelerator Facility (CEBAF) photoinjector and one unused, were also analyzed using Transmission Electron Microscopy (TEM) and SIMS. It was found that heat cleaning the FEL GaAs wafer introduces surface roughness, which seems to be reduced by prolonged use. The bulk GaAs samples retained a fairly well organized crystalline structure after delivering beam but shows evidence of Cs depletion on the surface. Within the precision of the SIMS and RBS measurements the data showed no indication of hydrogen implantation or lattice damage from ion back bombardment in the bulk GaAs wafers. In contrast, SIMS and TEM measurements of the strained superlattice photocathode show clear crystal damage in the wafer from ion back bombardment.

  6. Concentration transient analysis of antimony surface segregation during Si(100) molecular beam epitaxy

    Science.gov (United States)

    Markert, L. C.; Greene, J. E.; Ni, W.-X.; Hansson, G. V.; Sundgren, J.-E.

    1991-01-01

    Antimony surface segregation during Si(100) molecular beam epitaxy (MBE) was investigated at temperatures T(sub s) = 515 - 800 C using concentration transient analysis (CTA). The dopant surface coverage Theta, bulk fraction gamma, and incorporation probability sigma during MBE were determined from secondary-ion mass spectrometry depth profiles of modulation-doped films. Programmed T(sub s) changes during growth were used to trap the surface-segregated dopant overlayer, producing concentration spikes whose integrated area corresponds to Theta. Thermal antimony doping by coevaporation was found to result in segregation strongly dependent on T(sub s) with Theta(sub Sb) values up to 0.9 monolayers (ML): in films doped with Sb(+) ions accelerated by 100 V, Theta(sub Sb) was less than or equal to 4 x 10(exp -3) ML. Surface segregation of coevaporated antimony was kinematically limited for the film growth conditions in these experiments.

  7. Particle beam experiments for the analysis of reactive sputtering processes in metals and polymer surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Corbella, Carles; Grosse-Kreul, Simon; Kreiter, Oliver; Arcos, Teresa de los; Benedikt, Jan; Keudell, Achim von [RD Plasmas with Complex Interactions, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum (Germany)

    2013-10-15

    A beam experiment is presented to study heterogeneous reactions relevant to plasma-surface interactions in reactive sputtering applications. Atom and ion sources are focused onto the sample to expose it to quantified beams of oxygen, nitrogen, hydrogen, noble gas ions, and metal vapor. The heterogeneous surface processes are monitored in situ by means of a quartz crystal microbalance and Fourier transform infrared spectroscopy. Two examples illustrate the capabilities of the particle beam setup: oxidation and nitriding of aluminum as a model of target poisoning during reactive magnetron sputtering, and plasma pre-treatment of polymers (PET, PP)

  8. Particle beam experiments for the analysis of reactive sputtering processes in metals and polymer surfaces.

    Science.gov (United States)

    Corbella, Carles; Grosse-Kreul, Simon; Kreiter, Oliver; de los Arcos, Teresa; Benedikt, Jan; von Keudell, Achim

    2013-10-01

    A beam experiment is presented to study heterogeneous reactions relevant to plasma-surface interactions in reactive sputtering applications. Atom and ion sources are focused onto the sample to expose it to quantified beams of oxygen, nitrogen, hydrogen, noble gas ions, and metal vapor. The heterogeneous surface processes are monitored in situ by means of a quartz crystal microbalance and Fourier transform infrared spectroscopy. Two examples illustrate the capabilities of the particle beam setup: oxidation and nitriding of aluminum as a model of target poisoning during reactive magnetron sputtering, and plasma pre-treatment of polymers (PET, PP).

  9. On-site analysis of modified surface using dual beam system

    Energy Technology Data Exchange (ETDEWEB)

    Naramoto, Hiroshi; Aoki, Yasushi; Yamamoto, Shunya; Goppelt-Langer, P.; Gan Mingle; Zeng Jianer; Takeshita, Hidefumi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    Recent results obtained using a dual ion beam system at JAERI/Takasaki are reported. In this system, both of ion implantation and ion beam analysis can be made alternatively or simultaneously at low temperatures. In sapphire implanted with {sup 51}V{sup +} ions, the amorphization process is analyzed referring to the <0001> aligned spectra taken at different temperatures. The discussion is made on the defect profiles different from the simple accumulation of standard Gaussian form. The depth showing the maximum damage at the initial stage of implantation is quite shallow compared with those reported before. The thermal annealing behaviors of lattice damage and the implanted V atoms are also different between the samples implanted at low and room temperatures. In the former one fine particles of vanadium oxide are formed coherently with the easy recovery in high dose sample but in the latter the mixed oxide alloy is formed. (author)

  10. Structural analysis of the outermost hair surface using TOF-SIMS with gas cluster ion beam sputtering.

    Science.gov (United States)

    Lshikawa, Kazutaka; Okamoto, Masayuki; Aoyagi, Satoka

    2016-06-28

    A hair cuticle, which consists of flat overlapping scales that surround the hair fiber, protects inner tissues against external stimuli. The outermost surface of the cuticle is covered with a thin membrane containing proteins and lipids called the epicuticle. In a previous study, the authors conducted a depth profile analysis of a hair cuticle's amino acid composition to characterize its multilayer structure. Time-of-flight secondary ion mass spectrometry with a bismuth primary ion source was used in combination with the C60 sputtering technique for the analysis. It was confirmed that the lipids and cysteine-rich layer exist on the outermost cuticle surface, which is considered to be the epicuticle, though the detailed structure of the epicuticle has not been clarified. In this study, depth profile analysis of the cuticle surface was conducted using the argon gas cluster ion beam (Ar-GCIB) sputtering technique, in order to characterize the structure of the epicuticle. The shallow depth profile of the cuticle surface was investigated using an Ar-GCIB impact energy of 5 keV. Compared to the other amino acid peaks rich in the epicuticle, the decay of 18-methyleicosanic acid (18-MEA) thiolate peak was the fastest. This result suggests that the outermost surface of the hair is rich in 18-MEA. In conclusion, our results indicate that the outermost surfaces of cuticles have a multilayer (lipid and protein layers), which is consistent with the previously proposed structure.

  11. Effect of electron beam irradiation on forensic evidence. 2. Analysis of writing inks on porous surfaces.

    Science.gov (United States)

    Ramotowski, Robert S; Regen, Erin M

    2007-05-01

    The effect of electron beam irradiation on a series of different writing inks is described. As the anthrax-tainted letters were discovered in October 2001, the U.S. government began to experiment with the use of the electron beam irradiation process for destroying such biological agents. Plans initially considered a large-scale countrywide use of this technology. However, over time the scope of this plan as well as the radiation dosage were reduced, especially when some adverse consequences to mailed items subjected to this process were observed. Little data existed at the time to characterize what level of damage might be expected to occur with common items sent through the mail. This was especially important to museums and other institutions that routinely ship valuable and historic items through the mail. Although the Smithsonian Institution initiated some studies of the effect of electron beam irradiation on archived materials, little data existed on the effect that this process would have on forensic evidence. Approximately 97 different black, blue, red, green, and yellow writing inks were selected. Writing ink types included ballpoint, gel, plastic/felt tip, and rollerball. All noncontrol samples were subjected to standard mail irradiation conditions used by the U.S. Postal Service at the time this experiment was performed. A video spectral comparator and thin-layer chromatography (TLC) analysis were used to evaluate both the control and the irradiated samples. Some published studies reported changes in the presence/absence of dye bands in the chromatograms of irradiated writing inks. Some of these studies report the formation of additional dye bands on the chromatogram while others report missing dye bands. However, using standard testing guidelines and procedures, none of the 97 irradiated inks tested were found to show any significant optical or chemical differences from the control samples. In addition, random testing of some of the ink samples using a

  12. High power beam analysis

    Science.gov (United States)

    Aharon, Oren

    2014-02-01

    In various modern scientific and industrial laser applications, beam-shaping optics manipulates the laser spot size and its intensity distribution. However the designed laser spot frequently deviates from the design goal due to real life imperfections and effects, such as: input laser distortions, optical distortion, heating, overall instabilities, and non-linear effects. Lasers provide the ability to accurately deliver large amounts of energy to a target area with very high accuracy. Thus monitoring beam size power and beam location is of high importance for high quality results and repeatability. Depending on the combination of wavelength, beam size and pulse duration , laser energy is absorbed by the material surface, yielding into processes such as cutting, welding, surface treatment, brazing and many other applications. This article will cover the aspect of laser beam measurements, especially at the focal point where it matters the most. A brief introduction to the material processing interactions will be covered, followed by fundamentals of laser beam propagation, novel measurement techniques, actual measurement and brief conclusions.

  13. Deflection of proton beams by crystal miscut surface

    CERN Document Server

    Babaev, A A; Dabagov, S B

    2014-01-01

    First computer experiment results on proton beam deflection by the crystal miscut surface are presented. The phenomenology of proton channeling and quasichanneling has been applied to describe new features of the beam deflection. The analysis predicts efficient beam deflection by the acute crystal end due to repelling miscut potential.

  14. Quality Control of Laser-Beam-Melted Parts by a Correlation Between Their Mechanical Properties and a Three-Dimensional Surface Analysis

    Science.gov (United States)

    Grimm, T.; Wiora, G.; Witt, G.

    2017-03-01

    Good correlations between three-dimensional surface analyses of laser-beam-melted parts of nickel alloy HX and their mechanical properties were found. The surface analyses were performed with a confocal microscope, which offers a more profound surface data basis than a conventional, two-dimensional tactile profilometry. This new approach results in a wide range of three-dimensional surface parameters, which were each evaluated with respect to their feasibility for quality control in additive manufacturing. As a result of an automated surface analysis process by the confocal microscope and an industrial six-axis robot, the results are an innovative approach for quality control in additive manufacturing.

  15. Superdirected Beam of the Surface Spin Wave

    CERN Document Server

    Annenkov, Alexander Yu; Lock, Edwin H

    2016-01-01

    Visualized diffraction patterns of the surface spin wave excited by arbitrarily oriented linear transducer in tangentially magnetized ferrite film are investigated experimentally in the plane of ferrite film for the case where the transducer length D is much larger than the wavelength L. Superdirected (nonexpanding) beam of the surface spin wave with noncollinear wave vector k and group velocity vector V was observed experimentally: the angular width of this beam was about zero, the smearing of the beam energy along the film plane was minimal and the length of the beam trajectory was maximal (50 mm). Thus it was shown that such phenomenon as superdirected propagation of the wave exists in the nature.

  16. Surface analysis.

    Science.gov (United States)

    Kinsella, T

    2006-10-01

    Surface analysis techniques are important tools to use in the verification of surface cleanliness and medical device functionality. How these techniques can be employed and some example applications are described.

  17. Orientation-free and differentially pumped addition of a low-flux reactive gas beam to a surface analysis system

    Science.gov (United States)

    Harthcock, Colin; Jahanbekam, Abdolreza; Eskelsen, Jeremy R.; Lee, David Y.

    2016-11-01

    We describe an example of a piecewise gas chamber that can be customized to incorporate a low flux of gas-phase radicals with an existing surface analysis chamber for in situ and stepwise gas-surface interaction experiments without any constraint in orientation. The piecewise nature of this gas chamber provides complete angular freedom and easy alignment and does not require any modification of the existing surface analysis chamber. In addition, the entire gas-surface system is readily differentially pumped with the surface chamber kept under ultra-high-vacuum during the gas-surface measurements. This new design also allows not only straightforward reconstruction to accommodate the orientation of different surface chambers but also for the addition of other desired features, such as an additional pump to the current configuration. Stepwise interaction between atomic oxygen and a highly ordered pyrolytic graphite surface was chosen to test the effectiveness of this design, and the site-dependent O-atom chemisorption and clustering on the graphite surface were resolved by a scanning tunneling microscope in the nm-scale. X-ray photoelectron spectroscopy was used to further confirm the identity of the chemisorbed species on the graphite surface as oxygen.

  18. Surface angular momentum of light beams.

    Science.gov (United States)

    Ornigotti, Marco; Aiello, Andrea

    2014-03-24

    Traditionally, the angular momentum of light is calculated for "bullet-like" electromagnetic wave packets, although in actual optical experiments "pencil-like" beams of light are more commonly used. The fact that a wave packet is bounded transversely and longitudinally while a beam has, in principle, an infinite extent along the direction of propagation, renders incomplete the textbook calculation of the spin/orbital separation of the angular momentum of a light beam. In this work we demonstrate that a novel, extra surface part must be added in order to preserve the gauge invariance of the optical angular momentum per unit length. The impact of this extra term is quantified by means of two examples: a Laguerre-Gaussian and a Bessel beam, both circularly polarized.

  19. Surface processing using water cluster ion beams

    Science.gov (United States)

    Takaoka, Gikan H.; Ryuto, Hiromichi; Takeuchi, Mitsuaki; Ichihashi, Gaku

    2013-07-01

    Vaporized water clusters were produced by an adiabatic expansion phenomenon, and various substrates such as Si(1 0 0), SiO2, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polycarbonate (PC) were irradiated by water cluster ion beams. The sputtered depth increased with increasing acceleration voltage, and the sputtering rate was much larger than that obtained using Ar monomer ion irradiation. The sputtering yield for PMMA was approximately 200 molecules per ion, at an acceleration voltage of 9 kV. X-ray photoelectron spectroscopy (XPS) measurements showed that high-rate sputtering for the PMMA surface can be ascribed to the surface erosion by the water cluster ion irradiation. Furthermore, the micropatterning was demonstrated on the PMMA substrate. Thus, the surface irradiation by water cluster ion beams exhibited a chemical reaction based on OH radicals, as well as excited hydrogen atoms, which resulted in a high sputtering rate and low irradiation damage of the substrate surfaces.

  20. Surface processing using water cluster ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Takaoka, Gikan H., E-mail: gtakaoka@kuee.kyoto-u.ac.jp [Photonics and Electronics Science and Engineering Center, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Ryuto, Hiromichi; Takeuchi, Mitsuaki; Ichihashi, Gaku [Photonics and Electronics Science and Engineering Center, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2013-07-15

    Vaporized water clusters were produced by an adiabatic expansion phenomenon, and various substrates such as Si(1 0 0), SiO{sub 2}, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polycarbonate (PC) were irradiated by water cluster ion beams. The sputtered depth increased with increasing acceleration voltage, and the sputtering rate was much larger than that obtained using Ar monomer ion irradiation. The sputtering yield for PMMA was approximately 200 molecules per ion, at an acceleration voltage of 9 kV. X-ray photoelectron spectroscopy (XPS) measurements showed that high-rate sputtering for the PMMA surface can be ascribed to the surface erosion by the water cluster ion irradiation. Furthermore, the micropatterning was demonstrated on the PMMA substrate. Thus, the surface irradiation by water cluster ion beams exhibited a chemical reaction based on OH radicals, as well as excited hydrogen atoms, which resulted in a high sputtering rate and low irradiation damage of the substrate surfaces.

  1. Reduction of Glass Surface Reflectance by Ion Beam Surface Modification

    Energy Technology Data Exchange (ETDEWEB)

    Mark Spitzer

    2011-03-11

    This is the final report for DOE contract DE-EE0000590. The purpose of this work was to determine the feasibility of the reduction of the reflection from the front of solar photovoltaic modules. Reflection accounts for a power loss of approximately 4%. A solar module having an area of one square meter with an energy conversion efficiency of 18% generates approximately 180 watts. If reflection loss can be eliminated, the power output can be increased to 187 watts. Since conventional thin-film anti-reflection coatings do not have sufficient environmental stability, we investigated the feasibility of ion beam modification of the glass surface to obtain reduction of reflectance. Our findings are generally applicable to all solar modules that use glass encapsulation, as well as commercial float glass used in windows and other applications. Ion implantation of argon, fluorine, and xenon into commercial low-iron soda lime float glass, standard float glass, and borosilicate glass was studied by implantation, annealing, and measurement of reflectance. The three ions all affected reflectance. The most significant change was obtained by argon implantation into both low-iron and standard soda-lime glass. In this way samples were formed with reflectance lower than can be obtained with a single-layer coatings of magnesium fluoride. Integrated reflectance was reduced from 4% to 1% in low-iron soda lime glass typical of the glass used in solar modules. The reduction of reflectance of borosilicate glass was not as large; however borosilicate glass is not typically used in flat plate solar modules. Unlike conventional semiconductor ion implantation doping, glass reflectance reduction was found to be tolerant to large variations in implant dose, meaning that the process does not require high dopant uniformity. Additionally, glass implantation does not require mass analysis. Simple, high current ion implantation equipment can be developed for this process; however, before the process

  2. Reactive ion beam figuring of optical aluminium surfaces

    Science.gov (United States)

    Bauer, Jens; Frost, Frank; Arnold, Thomas

    2017-03-01

    Ultra-smooth and arbitrarily shaped reflective optics are necessary for further progress in EUV/XUV lithography, x-ray and synchrotron technology. As one of the most important technological mirror optic materials, aluminium behaves in a rather difficult way in ultra-precision machining with such standard techniques as diamond-turning and subsequent ion beam figuring (IBF). In particular, in the latter, a strong surface roughening is obtained. Hence, up to now it has not been possible to attain the surface qualities required for UV or just visible spectral range applications. To overcome the limitations mainly caused by the aluminium alloy structural and compositional conditions, a reactive ion beam machining process using oxygen process gas is evaluated. To clarify the principle differences in the effect of oxygen gas contrary to oxygen ions on aluminium surface machining, we firstly focus on chemical-assisted ion beam etching (CAIBE) and reactive ion beam etching (RIBE) experiments in a phenomenological manner. Then, the optimum process route will be explored within a more quantitative analysis applying the concept of power spectral density (PSD) for a sophisticated treatment of the surface topography. Eventually, the surface composition is examined by means of dynamic secondary ion mass spectrometry (SIMS) suggesting a characteristic model scheme for the chemical modification of the aluminium surface during oxygen ion beam machining. Monte Carlo simulations were applied to achieve a more detailed process conception.

  3. Electron-beam-assisted Scanning Tunneling Microscopy Of Insulating Surfaces

    CERN Document Server

    Bullock, E T

    2000-01-01

    Insulating materials are widely used in electronic devices. Bulk insulators and insulating films pose unique challenges for high resolution study since most commonly used charged particle surface analysis techniques are incompatible with insulating surfaces and materials. A, method of performing scanning tunneling microscopy (STM) on insulating surfaces has been investigated. The method is referred to as electron-beam assisted scanning tunneling microscopy (e-BASTM). It is proposed that by coupling the STM and the scanning electron microscopy (SEM) as one integrated device, that insulating materials may be studied, obtaining both high spatial resolution, and topographic and electronic resolution. The premise of the technique is based on two physical consequences of the interaction of an energetic electron beam (PE) with a material. First, when an electron beam is incident upon a material, low level material electrons are excited into conduction band states. For insulators, with very high secondary electron yi...

  4. Method based on artificial excitation of characteristic radiation by an electron beam for remote X-ray spectral elemental analysis of surface rocks on atmosphereless celestial bodies

    Science.gov (United States)

    Kolesnikov, E. K.

    2016-11-01

    This article, like our previous one [1], is devoted to advanced space technology concepts. It evaluates the potential for developing active systems to conduct a remote elemental analysis of surface rocks on an atmosphereless celestial body. The analysis is based on the spectrometry of characteristic X-rays (CXR) artificially excited in the surface soil layer. It has been proposed to use an electron beam injected from aboard a spacecraft orbiting the celestial body (or moving in a flyby trajectory) to excite the CXR elements contained in surface rocks. The focus is on specifying technical requirements to the parameters of payloads for a global mapping of the composition of lunar rocks from aboard of a low-orbiting lunar satellite. This article uses the results obtained in [2], our first study that shows the potential to develop an active system for a remote elemental analysis of lunar surface rocks using the above method. Although there has been interest in our research on the part of leading national academic institutions and space technology developers in the Soviet Union, the studies were discontinued because of the termination of the Soviet lunar program and the completion of the American Apollo program.

  5. Surface modification using ionic liquid ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Takaoka, Gikan H.; Hamaguchi, Takuya; Takeuchi, Mitsuaki; Ryuto, Hiromichi

    2014-12-15

    We developed an ionic liquid (IL) ion source using 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF{sub 6}) and produced IL ion beams by applying a high electric field between the tip and the extractor. Time-of-flight measurements showed that small cluster and fragment ions were contained in the positive and negative ion beams. The positive and negative cluster ions were deposited on Si(1 0 0) substrates. X-ray photoelectron spectroscopy measurements showed that the composition of the deposited layers was similar to that of an IL solvent. This suggests that a cation (A{sup +}) or an anion (B{sup −}) was attached to an IL cluster (AB){sub n}, resulting in the formation of positive cluster ions (AB){sub n}A{sup +} or negative cluster ions (AB){sub n}B{sup −}, respectively. The surfaces of the IL layers deposited on Si(1 0 0) substrates were flat at an atomic level for positive and negative cluster ion irradiation. Moreover, the contact angles of the deposited layers were similar to that of the IL solvent. Thus, surface modification of Si(1 0 0) substrates was successfully demonstrated with BMIM-PF{sub 6} cluster ion beams.

  6. Electron beam induced surface activation of oxide surfaces for nanofabrication

    Energy Technology Data Exchange (ETDEWEB)

    Vollnhals, Florian; Seiler, Steffen; Walz, Marie-Madeleine; Steinrueck, Hans-Peter; Marbach, Hubertus [Lehrstuhl fuer Physikalische Chemie II and Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen (Germany); Woolcot, Tom; Thornton, Geoff [London Centre for Nanotechnology and Department of Chemistry, University College London (United Kingdom)

    2012-07-01

    The controlled fabrication of structures on the nanoscale is a major challenge in science and engineering. Direct-write techniques like Electron Beam Induced Deposition (EBID) were shown to be suitable tools in this context. Recently, Electron Beam Induced Surface Activation (EBISA) has been introduced as a new focused electron beam technique. In EBISA, a surface, e.g. SiO{sub 2}, is irradiated by a focused electron beam, resulting in an activation of the exposed area. The activated area can then react and decompose precursor gases like iron pentacarbonyl, Fe(CO){sub 5}. This leads to a primary deposit, which continues to grow autocatalytically as long as Fe(CO){sub 5} is supplied, resulting in pure (> 90 % at.), crystalline iron nanostructures. We expand the use of this concept by exploring EBISA to produce metallic nanostructures on TiO{sub 2}(110) in UHV; atomistic insight into the process is obtained via Scanning Tunneling Microscopy (STM) and chemical insight via Auger Electron Spectroscopy (AES).

  7. Tractor beam on the water surface

    CERN Document Server

    Punzmann, Horst; Xia, Hua; Falkovich, Gregory; Shats, Michael

    2014-01-01

    Can one send a wave to bring an object from a distance? The general idea is inspired by the recent success in moving micro particles using light and the development of a tractor beam concept. For fluid surfaces, however, the only known paradigm is the Stokes drift model, where linear planar waves push particles in the direction of the wave propagation. Here we show how to fetch a macroscopic floater from a large distance by sending a surface wave towards it. We develop a new method of remote manipulation of floaters by forming inward and outward surface jets, stationary vortices, and other complex surface flows using nonlinear waves generated by a vertically oscillating plunger. The flows can be engineered by changing the geometry and the power of a wave maker, and the flow dissipation. The new method is robust and works both for long gravity and for short capillary waves. We use a novel method of visualising 3D particle trajectories on the surface. This letter introduces a new conceptual framework for unders...

  8. Plasmas and atom beam activation of the surface of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Santos, C; Yubero, F; Cotrino, J; Barranco, A; Gonzalez-Elipe, A R [Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla), Avda Americo Vespucio 49, E-41092 Sevilla (Spain)], E-mail: arge@icmse.csic.es

    2008-11-21

    Wetting properties of polyethylene terephthalate (PET) and low-density polyethylene polymers have been investigated after treatment with a microwave (MW) plasma discharge at low pressure and a dielectric barrier discharge at atmospheric pressure. Experiments have also been carried out in situ with an atom source installed in an x-ray photoemission spectrometer (XPS). The water contact angle measured on both polymers experienced a significant decrease after activation, but a progressive recovery up to different values after ageing. Standard chemical analysis by XPS showed that the plasma and oxygen beam treatments produced an increase in the concentration of -C(O){sub x} functional groups at the outermost surface layers of the treated polymers. Besides, the oxygen distribution between the topmost surface layer and the bulk has been obtained by non-destructive XPS peak shape analysis. Atomic force microscopy analysis of the surface topography showed that, except for PET treated with the MW plasma and the atom beam, the surface roughness increased after the plasma treatments. Wetting angle variations, oxygen content and distribution, surface roughness and evolution of these properties with time are comparatively discussed by taking into account the basic processes that each type of activation procedure induces in the outmost surface layers of the treated polymers.

  9. A Pulsed Laser and Molecular Beam Apparatus for Surface Studies

    Science.gov (United States)

    1985-03-01

    PRFCAMING ORCANIZATION REPORT NuMSWIS b MONITORING ORGANIZATION RPR :6P" _________ ______._ _ I0 0 1 I &PO*R.TR. o u 1 6NAEOF PERFORMING ORGANIZATION 5.OFFICE...with a second pulsed molecular beam, and the course of the reaction may be followed using several new pulsed surface analysis techniques under...available for electrical and manipulation feedthroughs, roughing and gas inlet lines, as well as special viewports (quartz or MgF 2) for the passage of UV

  10. Analysis of Bragg gratings for long-range surface plasmon polaritons using the bidirectional beam propagation method based on scattering operators

    Science.gov (United States)

    Zhang, Hua; Mu, Jianwei; Huang, Wei-Ping

    2007-09-01

    For realization of highly integrated optical circuits, various metallic nanostructures supporting the propagation of surface plasmon polaritons have been extensively studied experimentally and theoretically in recent years. This paper reports on the development of a numerically stable and accurate finite-difference-based bidirectional beam propagation method (FD-BiBPM) for analyzing piecewise z-invariant plasmonic structures. Our method is developed based on the scattering operators. The adoption of complex coefficient rational approximations to the square root operator allows to correctly model the propagation of evanescent modes excited at discontinuity interfaces. In view of the large index contrast at metal-dielectric interfaces, a fourth-order accurate finite difference formulation for discretization is incorporated to the present method and its fine treatment of these interfaces guarantees accuracy. By using the present method, the reflection and transmission spectra of the Bragg gratings consisting of a thin metal film embedded in dielectric medium and an array of equidistant metal ridges on each side of the film are calculated. The good agreement of our results with the previously reported simulations illustrates the potential of the newly developed FD-BiBPM for the analysis of longrange surface plasmon polariton (LRSPP) waves guided along the described Bragg gratings.

  11. Imaging physicochemical reactions occurring at the pore surface in binary bioactive glass foams by micro ion beam analysis.

    Science.gov (United States)

    Jallot, E; Lao, J; John, L; Soulié, J; Moretto, Ph; Nedelec, J M

    2010-06-01

    In this work, the physicochemical reactions occurring at the surface of bioactive sol-gel derived 3D glass scaffolds via a complete PIXE characterization were studied. 3D glass foams in the SiO(2)-CaO system were prepared by sol-gel route. Samples of glass scaffolds were soaked in biological fluids for periods up to 2 days. The surface changes were characterized using particle induced X-ray emission (PIXE) associated to Rutherford backscattering spectroscopy (RBS), which are efficient methods to perform quantitative chemical maps. Elemental maps of major and trace elements at the glass/biological fluids interface were obtained at the micrometer scale for every interaction time. Results revealed interconnected macropores and physicochemical reactions occurring at the surface of pores. The micro-PIXE-RBS characterization of the pores/biological fluids interface shows the glass dissolution and the rapid formation of a Ca rich layer with the presence of phosphorus that came from biological fluids. After 2 days, a calcium phosphate-rich layer containing magnesium is formed at the surface of the glass scaffolds. We demonstrate that quantities of phosphorus provided only by the biological medium have a significant impact on the development and the formation of the phosphocalcic layer.

  12. Effect of shape of elastic beam hair on its adhesion with wavy surfaces

    Science.gov (United States)

    Hemthavy, Pasomphone; Yazaki, Takehiko; Wang, Boqing; Sekiguchi, Yu; Takahashi, Kunio

    2014-08-01

    An analysis on a tapered elastic beam whose side surface partially adhered to a rigid surface was carried out to study the effect of the beam shape on the gripping force. Considering the total energy of the system, the relation between the gripping force and the displacement was obtained analytically in closed form. The analytical result is significant because it provides an intuitive picture of the gripping force. Although, an individually tapered beam can generate less gripping force for flat or slightly wavy surfaces, compared to a rectangular beam, the analysis result suggests that the tapered beam has more ability to absorb surface waviness. This result can be applied to a multi-beam structure.

  13. Accuracy of three-dimensional measurements obtained from cone beam computed tomography surface-rendered images for cephalometric analysis: influence of patient scanning position

    NARCIS (Netherlands)

    Hassan, B.; van der Stelt, P.; Sanderink, G.

    2009-01-01

    The aims of this study were to assess the accuracy of linear measurements on three-dimensional (3D) surface-rendered images generated from cone beam computed tomography (CBCT) in comparison with two-dimensional (2D) slices and 2D lateral and postero-anterior (PA) cephalometric projections, and to in

  14. Debye series analysis of internal and near-surface fields for a homogeneous sphere illuminated by an axicon-generated vector Bessel beam

    Science.gov (United States)

    Qin, Shitong; Li, Renxian; Yang, Ruiping; Ding, Chunying

    2017-07-01

    The interaction of an axicon-generated vector Bessel beam (AGVBB) with a homogeneous sphere is investigated in the framework of generalized Lorenz-Mie theory (GLMT). An analytical expression of beam shape coefficients (BSCs) is derived using angular spectrum decomposition method (ASDM), and the scattering coefficients are expanded using Debye series (DSE) in order to isolate the contribution of single scattering process. The internal and near-surface electric fields are numerically analyzed, and the effect of beam location, polarization, order of beam, half-cone angle, and scattering process (namely Debye mode p) are mainly discussed. Numerical results show that a curve formed by extreme peaks can be observed, and the electric fields can be locally enhanced after the interaction of AGVBBs with the particle. Internal and near-surface fields, especially its local enhancement, are very sensitive to the beam parameters, including polarization, order, half-cone angle, etc. The internal fields can also be enhanced by various scattering process (or Debye mode p). Such results have important applications in various fields, including particle sizing, optical tweezers, etc.

  15. Ion beam analysis fundamentals and applications

    CERN Document Server

    Nastasi, Michael; Wang, Yongqiang

    2015-01-01

    Ion Beam Analysis: Fundamentals and Applications explains the basic characteristics of ion beams as applied to the analysis of materials, as well as ion beam analysis (IBA) of art/archaeological objects. It focuses on the fundamentals and applications of ion beam methods of materials characterization.The book explains how ions interact with solids and describes what information can be gained. It starts by covering the fundamentals of ion beam analysis, including kinematics, ion stopping, Rutherford backscattering, channeling, elastic recoil detection, particle induced x-ray emission, and nucle

  16. Electron beam induced oxidation of Al–Mg alloy surfaces

    NARCIS (Netherlands)

    Palasantzas, G.; Agterveld, D.T.L. van; Hosson, J.Th.M. De

    2002-01-01

    Electron beam currents of a few nanoamperes, currently used in nanometer scale scanning Auger/electron microscopy, induces severe oxidation of Al–Mg alloy surfaces at room temperature. Auger peak-to-peak oxygen curves for Al–Mg surfaces support the hypothesis that the electron beam creates

  17. Electron beam induced oxidation of Al–Mg alloy surfaces

    NARCIS (Netherlands)

    Palasantzas, G.; Agterveld, D.T.L. van; Hosson, J.Th.M. De

    2002-01-01

    Electron beam currents of a few nanoamperes, currently used in nanometer scale scanning Auger/electron microscopy, induces severe oxidation of Al–Mg alloy surfaces at room temperature. Auger peak-to-peak oxygen curves for Al–Mg surfaces support the hypothesis that the electron beam creates additiona

  18. Upper limit of the muon-neutrino mass and charged-pion mass from the momentum analysis of a surface muon beam

    Energy Technology Data Exchange (ETDEWEB)

    Kettle, P.R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    Using a surface muon beam and a magnetic spectrometer equipped with a position-sensitive detector, we have measured the muon momentum from pion decay at rest {pi}{sup +}{yields}{mu}{sup +}{nu}{sub {mu}}, to be p{sub {mu}{sup +}}=(29.79200{+-}0.00011)MeV/c. This value together with the muon mass and the favoured pion mass leads to an upper limit of 0.17 MeV (90%CL) for the muon-neutrino mass. (author) 4 figs., 5 refs.

  19. Ion-Beam Analysis of Airborne Pollution

    Science.gov (United States)

    Harrington, Charles; Gleason, Colin; Schuff, Katie; Battaglia, Maria; Moore, Robert; Turley, Colin; Labrake, Scott; Vineyard, Michael

    2010-11-01

    An undergraduate laboratory research program in ion-beam analysis (IBA) of atmospheric aerosols is being developed to study pollution in the Capitol District and Adirondack Mountains of New York. The IBA techniques applied in this project include proton induced X-ray emission (PIXE), proton induced gamma-ray emission (PIGE), Rutherford backscattering (RBS), and proton elastic scattering analysis (PESA). These methods are well suited for studying air pollution because they are quick, non-destructive, require little to no sample preparation, and capable of investigating microscopic samples. While PIXE spectrometry is used to analyze most elements from silicon to uranium, the other techniques are being applied to measure some of the remaining elements and complement PIXE in the study of aerosols. The airborne particulate matter is collected using nine-stage cascade impactors that separate the particles according to size and the samples are bombarded with proton beams from the Union College 1.1-MV Pelletron Accelerator. The reaction products are measured with SDD X-ray, Ge gamma-ray, and Si surface barrier charged particle detectors. Here we report on the progress we have made on the PIGE, RBS, and PESA analysis of aerosol samples.

  20. Hydrophobicity of electron beam modified surface of hydroxyapatite films

    Energy Technology Data Exchange (ETDEWEB)

    Gregor, M., E-mail: gregor@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Plecenik, T. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Tofail, S.A.M. [Materials & Surface Science Institute, University of Limerick, Limerick (Ireland); Zahoran, M.; Truchly, M. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Vargova, M. [Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, 84215 Bratislava (Slovakia); Laffir, F. [Materials & Surface Science Institute, University of Limerick, Limerick (Ireland); Plesch, G. [Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, 84215 Bratislava (Slovakia); Kus, P.; Plecenik, A. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia)

    2015-05-15

    Highlights: • Surface potential of hydroxyapatite films were modified by focused electron beam. • Micron-sized domains of modified surface potential were created. • Wettability and surface free energy of the irradiated areas was studied. • Possible mechanisms of increased surface hydrophobicity are discussed. - Abstract: Arrays of micron-sized domains of modified surface potential were created on hydroxyapatite films by mid-energy (20 keV) electron beam irradiation available in a laboratory scanning electron microscope. The dosage of electron beam was varied between 10{sup −3} and 10{sup 3} μC/cm{sup 2} to inject charge into the film surface. Contrary to the conventional electrowetting theory, the dosage of injected charge used in creating such microdomains caused a gradual increase of the water contact angle from 57° to 93° due to the elimination of the polar component of the surface free energy. Surface contamination by carbonaceous species can be held only partially responsible for such behavior at lower dosage of electron beam. A transfer of free surface charge to water and an electron beam induced disruption of polar orientation of OH ions have been attributed to be influencial factors in the overall dewetting behavior.

  1. The Variation of Surface Dose by Beam Spoiler in 10 MV Photon Beam from Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Seong Cheol; Kim, Jun Ho; Lee, Choul Soo [Dept. of Radiation Oncology, Kosin University Gospel Hospital, Busan (Korea, Republic of)

    2006-03-15

    The purpose of this study is to find a optimal beam spoiler condition on the dose distribution near the surface, when treating a squamous cell carcinoma of the head and neck and a lymphatic region with 10 MV photon beam. The use of a optimal spoiler allows delivering high dose to a superficial tumor volume, while maintaining the skin-sparing effect in the area between the surface to the depth of 0.4 cm. The lucite beam spoiler, which were a tissue equivalent, were made and placed between the surface and the photon collimators of linear accelerator. The surface-dose, the dose at the depth of 0.4 cm, and the maximum dose at the dmax were measured with a parallel-plate ionization chamber for 5 x 5 cm to 30 x 30 cm{sup 2} field sizes using lucite spoilers with different thicknesses at varying skin-to-spoiler separation (SSS). In the same condition, the dose was measured with bolus and compared with beam spoiler. The spoiler increased the surface and build-up dose and shifted the depth of maximum dose toward the surface. With a 10 MV x-ray beam and a optimal beam spoiler when treating a patient, a similar build-up dose with a 6 MV photon beam could be achieved, while maintaining a certain amount of skin spring. But it was provided higher surface dose under SSS of less than 5 cm, the spoiler thickness of more than 1.8 cm or more, and larger field size than 20 x 20 cm{sup 2} provided higher surface dose like bolus and obliterated the spin-sparing effect. the effects of the beam spoiler on beam profile was reduced with increasing depths. The lucite spoiler allowed using of a 10 MV photon beam for the radiation treatment of head and neck caner by yielding secondary scattered electron on the surface. The dose at superficial depth was increased and the depth of maximum dose was moved to near the skin surface. Spoiling the 10 MV x-ray beam resulted in treatment plans that maintained dose homogeneity without the consequence of increased skin reaction or treat volume underdose

  2. Supersonic molecular beam experiments on surface chemical reactions.

    Science.gov (United States)

    Okada, Michio

    2014-10-01

    The interaction of a molecule and a surface is important in various fields, and in particular in complex systems like biomaterials and their related chemistry. However, the detailed understanding of the elementary steps in the surface chemistry, for example, stereodynamics, is still insufficient even for simple model systems. In this Personal Account, I review our recent studies of chemical reactions on single-crystalline Cu and Si surfaces induced by hyperthermal oxygen molecular beams and by oriented molecular beams, respectively. Studies of oxide formation on Cu induced by hyperthermal molecular beams demonstrate a significant role of the translational energy of the incident molecules. The use of hyperthermal molecular beams enables us to open up new chemical reaction paths specific for the hyperthermal energy region, and to develop new methods for the fabrication of thin films. On the other hand, oriented molecular beams also demonstrate the possibility of understanding surface chemical reactions in detail by varying the orientation of the incident molecules. The steric effects found on Si surfaces hint at new ways of material fabrication on Si surfaces. Controlling the initial conditions of incoming molecules is a powerful tool for finely monitoring the elementary step of the surface chemical reactions and creating new materials on surfaces.

  3. Ion beam analysis of diffusion in heterogeneous materials

    Energy Technology Data Exchange (ETDEWEB)

    Clough, A.S.; Jenneson, P.M. [Surrey Univ., Guildford (United Kingdom). Dept. of Physics

    1998-04-01

    Ion-beam analysis has been applied to a variety of problems involving diffusion in heterogeneous materials. An energy loss technique has been used to study both the diffusion of water and the surface segregation of fluoropolymers in polymeric matrices. A scanning micro-beam technique has been developed to allow water concentrations in hydrophilic polymers and cements to be measured together with associated solute elements. It has also been applied to the diffusion of shampoo into hair. (orig.) 13 refs.

  4. Thermal analysis of the SSC beam scraper

    Energy Technology Data Exchange (ETDEWEB)

    Tran, N.; Dao, B.

    1993-04-01

    When a particle beam impacts a beam scraper, heat is generated resulting in a rise in the temperature of the material. The maximum temperature rise should be kept to a minimum in order to maintain scraper efficiency and performance. In this paper the results of a thermal analysis of a scraper are presented.

  5. Output beam analysis of high power COIL

    Institute of Scientific and Technical Information of China (English)

    Deli Yu(于德利); Fengting Sang(桑凤亭); Yuqi Jin(金玉奇); Yizhu Sun(孙以珠)

    2003-01-01

    As the output power of a chemical oxygen iodine laser (COIL) increases, the output laser beam instabilityappears as the far-field beam spot drift and deformation for the large Fresnel number unstable resonator.In order to interpret this phenomenon, an output beam mode simulation code was developed with the fastFourier transform method. The calculation results show that the presence of the nonuniform gain in COILproduces a skewed output intensity distribution, which causes the mirror tilt and bulge due to the thermalexpansion. With the output power of COIL increases, the mirror surfaces, especially the back surface ofthe scraper mirror, absorb more and more heat, which causes the drift and deformation of far field beamspot seriously. The initial misalignment direction is an important factor for the far field beam spot driftingand deformation.

  6. Metal surface temperature induced by moving laser beams

    NARCIS (Netherlands)

    Römer, G.R.B.E.; Meijer, J.

    1995-01-01

    Whenever a metal is irradiated with a laser beam, electromagnetic energy is transformed into heat in a thin surface layer. The maximum surface temperature is the most important quantity which determines the processing result. Expressions for this maximum temperature are provided by the literature fo

  7. Surface characterization after subaperture reactive ion beam etching

    Energy Technology Data Exchange (ETDEWEB)

    Miessler, Andre; Arnold, Thomas; Rauschenbach, Bernd [Leibniz-Institut fuer Oberflaechenmodifizierung (IOM), Leipzig (Germany)

    2010-07-01

    In usual ion beam etching processes using inert gas (Ar, Xe, Kr..) the material removal is determined by physical sputtering effects on the surface. The admixture of suitable gases (CF{sub 4}+O{sub 2}) into the glow discharge of the ion beam source leads to the generation of reactive particles, which are accelerated towards the substrate where they enhance the sputtering process by formation of volatile chemical reaction products. During the last two decades research in Reactive Ion Beam Etching (RIBE) has been done using a broad beam ion source which allows the treatment of smaller samples (diameter sample < diameter beam). Our goal was to apply a sub-aperture Kaufman-type ion source in combination with an applicative movement of the sample with respect to the source, which enables us to etch areas larger than the typical lateral dimensions of the ion beam. Concerning this matter, the etching behavior in the beam periphery plays a decisive role and has to be investigated. We use interferometry to characterize the final surface topography and XPS measurements to analyze the chemical composition of the samples after RIBE.

  8. Induction of surface modification of polytetrafluoroethylene with proton ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Noh, I. S.; Kim, H. R.; Choi, Y. J.; Park, H. S. [Seoul National Univ. of Technology, Seoul (Korea, Republic of)

    2007-04-15

    Cardiovascular disease is one of the leading causes of the death in the USA and developed countries. More than 570,000 artery bypass graft surgeries per USA are performed each year, though percutaneous devices have abounded in extreme cases. Based on the surgery follow-ups, large diameter expanded polytetrafluoroethylene (ePTFE) (>5 mm) are clinically employed with good results but its clinical applications in smaller vessels is still problematic due to thrombosis and neointima formation. Achievement of high patency grafts has been to some extent achieved by numerous methods of surface modification techniques, but its results are less than its initial hopes. As examples, endothelial cells coated on the luminal surface of ePTFE has demonstrated limited success after recirculation. Surface modifications of PTFE film with either argon ion beam or UV light from Xe-excimer lamp were reported to increase its interaction with vascular endothelial cell. Surface modification of poly(lactide-co-glycolide)[PLGA] is also very important in tissue engineering, in where induction of its initial high cellular adhesion and spreading is a critical step for development of tissue engineering medical products. We previously reported tissue engineering of the hybrid ePTFE scaffold by seeding smooth muscle cells and subsequently evaluation of its tissue regeneration behaviors and stabilities with circulation of pulsatile flow. To improve its tissue engineering more quickly, we here performed surface modification of ePTFE and porous PLGA scaffold and evaluated its subsequent chemical and biological properties after treating its surface with low energy ion beams. The porous ePTFE was prepared in a round shape (diameter = 1 cm) and dried after organic solvent extraction for ion beam treatment. Another porous PLGA layers (d = 1 cm, t = 1 cm with approximately 92% porosity) were fabricated and treated its surface by irradiating low energy either nitrogen or argon ion beams (1 keV, 1x1015 ions

  9. Surface, structural and tensile properties of proton beam irradiated zirconium

    Science.gov (United States)

    Rafique, Mohsin; Chae, San; Kim, Yong-Soo

    2016-02-01

    This paper reports the surface, structural and tensile properties of proton beam irradiated pure zirconium (99.8%). The Zr samples were irradiated by 3.5 MeV protons using MC-50 cyclotron accelerator at different doses ranging from 1 × 1013 to 1 × 1016 protons/cm2. Both un-irradiated and irradiated samples were characterized using Field Emission Scanning Electron Microscope (FESEM), X-ray Diffraction (XRD) and Universal Testing Machine (UTM). The average surface roughness of the specimens was determined by using Nanotech WSxM 5.0 develop 7.0 software. The FESEM results revealed the formation of bubbles, cracks and black spots on the samples' surface at different doses whereas the XRD results indicated the presence of residual stresses in the irradiated specimens. Williamson-Hall analysis of the diffraction peaks was carried out to investigate changes in crystallite size and lattice strain in the irradiated specimens. The tensile properties such as the yield stress, ultimate tensile stress and percentage elongation exhibited a decreasing trend after irradiation in general, however, an inconsistent behavior was observed in their dependence on proton dose. The changes in tensile properties of Zr were associated with the production of radiation-induced defects including bubbles, cracks, precipitates and simultaneous recovery by the thermal energy generated with the increase of irradiation dose.

  10. Aspects of Metal Surface Glowing Mechanisms with Intensive Electron Beam Bombardment

    Directory of Open Access Journals (Sweden)

    I.V. Barsuk

    2012-06-01

    Full Text Available The paper gives a brief description and analysis of the main physical processes which can have an effect on the glowing nature of metal element surfaces in different electric vacuum devices when they are bombarded by electron beams. It has been found that the electron glowing effects on metal surfaces according to the electron energy can be explained with the help of the transition scattering on plasma waves or just with the classical transition radiation effect. This fact is rather important in terms of classical physics interpretation of the observed glowing effects on metal surface elements and techniques optimization of metal and electron beams diagnostics as well.

  11. Beam-propagation method - Analysis and assessment

    Science.gov (United States)

    van Roey, J.; van der Donk, J.; Lagasse, P. E.

    1981-07-01

    A method for the calculation of the propagation of a light beam through an inhomogeneous medium is presented. A theoretical analysis of this beam-propagation method is given, and a set of conditions necessary for the accurate application of the method is derived. The method is illustrated by the study of a number of integrated-optic structures, such as thin-film waveguides and gratings.

  12. Surface plasmon polariton beam focusing with parabolic nanoparticle chains

    DEFF Research Database (Denmark)

    Radko, Ilya P.; Bozhevolnyi, Sergey I.; Evlyukhin, Andrey B.

    2007-01-01

    We report on the focusing of surface plasmon polariton (SPP) beams with parabolic chains of gold nanoparticles fabricated on thin gold films. SPP focusing with different parabolic chains is investigated in the wavelength range of 700–860 nm, both experimentally and theoretically. Mapping of SPP...

  13. Surface plasmon interference excited by tightly focused laser beams.

    Energy Technology Data Exchange (ETDEWEB)

    Bouhelier, A.; Ignatovich, F.; Bruyant, A.; Huang, C.; Colas des Francs, G.; Weeber, J.-C.; Dereux, A.; Wiederrecht, G. P.; Novotny, L.; Center for Nanoscale Materials; Univ de Bourgogne; Univ. of Rochester; Univ Technologique de Troyes

    2007-09-01

    We show that interfering surface plasmon polaritons can be excited with a focused laser beam at normal incidence to a plane metal film. No protrusions or holes are needed in this excitation scheme. Depending on the axial position of the focus, the intensity distribution on the metal surface is either dominated by interferences between counterpropagating plasmons or by a two-lobe pattern characteristic of localized surface plasmon excitation. Our experiments can be accurately explained by use of the angular spectrum representation and provide a simple means for locally exciting standing surface plasmon polaritons.

  14. Surface modification of pure titanium by pulsed electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.D. [Key Laboratory of Materials Modification and School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Laboratoired' Etude des Microstructures et de Mecanique des Materiaux (LEM3), CNRS UMR 7239, Universite Paul Verlaine - Metz, Ile du Saulcy, 57045 Metz (France); Hao, S.Z., E-mail: ebeam@dlut.edu.cn [Key Laboratory of Materials Modification and School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Li, X.N. [Key Laboratory of Materials Modification and School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Dong, C., E-mail: dong@dlut.edu.cn [Key Laboratory of Materials Modification and School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Grosdidier, T., E-mail: Thierry.grosdidier@univ-metz.fr [Laboratoired' Etude des Microstructures et de Mecanique des Materiaux (LEM3), CNRS UMR 7239, Universite Paul Verlaine - Metz, Ile du Saulcy, 57045 Metz (France)

    2011-04-15

    The microstructure, hardness and corrosion resistance of commercially pure Ti treated by low energy high current pulsed electron beam (LEHCPEB) have been investigated. The thin near-surface melted layer rapidly solidified into {beta} and subsequently transformed into ultrafine {alpha}' martensite. This has led to a drastic improvement of the corrosion properties and a significant increase (more than 60%) in hardness of the top surface.

  15. Stiction of a Nano-Beam with Surface Effect

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-Lin; XIA Re; ZHOU Yue-Ting

    2011-01-01

    Nanowire stiction is a cruciai bottleneck for the development of M/NEMS devices. We present a model of a nano-beam stuck to te substrate in consideration of both surface elasticity and residual surface stress. The critical detachment length can be derived from the transversality condition using the variational method. The effects of the surface parameters on the adhesion of the nano-beam are discussed in detail. These analyses provide some suggestions for engineers in the design and fabrication of more accurate M/NEMS instruments.%Nanowire stiction is a crucial bottleneck for the development of M/NEMS devices.We present a model of a nano-beam stuck to the substrate in consideration of both surface elasticity and residual surface stress.The critical detachment length can be derived from the transversality condition using the variational method.The effects of the surface parameters on the adhesion of the nano-beam are discussed in detail.These analyses provide some suggestions for engineers in the design and fabrication of more accurate M/NEMS instruments.In the bottom-up approach,nanowires and nanobelts are widely used as the building blocks of micro/nano devices,such as micro-sensors,resonators,probes,transistors and actuators in micro/nanoelectro-mechanical systems (M/NMES).[1-3] Unfortunately,the stiction failure caused by spontaneous adhesion between M/NEMS structures has become a major limitation to push better application of these novel devices and this problem has been highlighted as a hot topic in the past decades.[4,5] The main reason of stiction is that in the small spacings,slender structures with high compliance are easily brought into contact with a substrate with strong surface energy.

  16. Ionic liquids influence on the surface properties of electron beam irradiated wood

    Energy Technology Data Exchange (ETDEWEB)

    Croitoru, Catalin [“Transilvania” University of Brasov, Product Design and Environment Department, 29 Eroilor Str., 500036, Brasov (Romania); Patachia, Silvia, E-mail: st.patachia@unitbv.ro [“Transilvania” University of Brasov, Product Design and Environment Department, 29 Eroilor Str., 500036, Brasov (Romania); Doroftei, Florica; Parparita, Elena; Vasile, Cornelia [“Petru Poni” Institute of Macromolecular Chemistry, Physical Chemistry of Polymers Department, 41A Gr. Ghica Voda Alley, Iasi (Romania)

    2014-09-30

    Highlights: • Wood veneers impregnated with three imidazolium-based ionic liquids and irradiated with electron beam were studied by FTIR-ATR, SEM/EDX, AFM, contact angle and image analysis. • ILs preserve the surface properties of the wood (surface energy, roughness, color) upon irradiation, in comparison with the reference wood, but the surface composition is changed by treatment with IL-s, mainly with 1-butyl-3-methylimidazolium tetrafluoroborate. • Under electron beam irradiation covalent bonding of the imidazolium moiety to wood determines a higher resistance to water penetration and spreading on the surface. - Abstract: In this paper, the influence of three imidazolium-based ionic liquids (1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-hexyl-3-methylimidazolium chloride) on the structure and surface properties of sycamore maple (Acer pseudoplatanus) veneers submitted to electron beam irradiation with a dose of 50 kGy has been studied by using Fourier transform infrared spectroscopy, as well as image, scanning electron microscopy/SEM/EDX, atomic force microscopy and contact angle analysis. The experimental results have proven that the studied ionic liquids determine a better preservation of the structural features of wood (cellulose crystallinity index and lignin concentration on the surface) as well as some of surface properties such as surface energy, roughness, color upon irradiation with electron beam, in comparison with the reference wood, but surface composition is changed by treatment with imidazolium-based ionic liquids mainly with 1-butyl-3-methylimidazolium tetrafluoroborate. Also, under electron beam irradiation covalent bonding of the imidazolium moiety to wood determines a higher resistance to water penetration and spreading on the surface.

  17. Optimization of Circular Side Door Beam for Crashworthiness Analysis

    Directory of Open Access Journals (Sweden)

    Raja Sharmi Raja Husin

    2012-01-01

    Full Text Available Structural optimization related to crashworthiness and energy absorption capability is particularly importance to the automotive industry. The optimization involves highly nonlinear computational analysis and design with many material and structure parameters. This paper presents a crashworthiness design of the circular side door beam which attach to the side door structures. The response surface method (RSM is utilized to formulate the complex crashworthiness design problem in the case of optimization. In this study, side door beam will be optimized. The beams in circular shape were studied and compared. The focus is on finding an optimum cross-section shape of the beam in order to improve the energy absorption character.  An optimization problem is formulated to find the maximum energy absorbed with the maximum peak load as a constraint, the shape of the beam cross section and the thickness as variable. The structure optimum design and simulation analysis of automobile side-door beam was carried out by using Finite Element (FE method.

  18. Application specific beam profiles: new surface and thin-film refinement processes using beam shaping technologies

    Science.gov (United States)

    Hauschild, Dirk

    2017-02-01

    Today, the use of laser photons for materials processing is a key technology in nearly all industries. Most of the applications use circular beam shapes with Gaussian intensity distribution that is given by the resonator of the laser or by the power delivery via optical fibre. These beam shapes can be typically used for material removal with cutting or drilling and for selective removal of material layers with ablation processes. In addition to the removal of materials, it is possible to modify and improve the material properties in case the dose of laser photons and the resulting light-material interaction addresses a defined window of energy and dwell-time. These process windows have typically dwell-times between µs and s because of using sintering, melting, thermal diffusion or photon induced chemical and physical reaction mechanisms. Using beam shaping technologies the laser beam profiles can be adapted to the material properties and time-temperature and the space-temperature envelopes can be modified to enable selective annealing or crystallization of layers or surfaces. Especially the control of the process energy inside the beam and at its edges opens a large area of laser applications that can be addressed only with an optimized spatial and angular beam profile with down to sub-percent intensity variation used in e.g. immersion lithography tools with ArF laser sources. LIMO will present examples for new beam shapes and related material refinement processes even on large surfaces and give an overview about new mechanisms in laser material processing for current and coming industrial applications.

  19. Module for dielectric surfaces modification by fast neutral particles beams

    Science.gov (United States)

    Barchenko, V. T.; Lisenkov, A. A.; Babinov, N. A.

    2014-11-01

    In this paper, we describe the module for dielectric and wide-gap semiconductor surfaces modification by fast neutral beam. The module can be used for cleaning, etching or assisting of films deposition. The surface proceeding by neutral beam can prevent an accumulation of surface charge without using current compensation by inserting electrons to the beam or RF power supply. The module beside cathode and anode contains an electrode with floating potential. Insertion of the additional electrode causes electron retention in an electrostatic trap resulting the reducing of the module operating pressure. Moreover, the electrode with floating potential allows increasing the current efficient of the module. An important feature of the module is that neutralization of the ions extracted from the plasma occurs in the cathode potential well. Thereby ions that have not neutralized cannot leave nearcathode region and there are no fast ions in the output beam. Module does not contain sources of the magnetic fields or elements heated by external sources. Module operates with free cooling. Thus, the module does not need water cooling and can be freely moved in the vacuum chamber.

  20. Application of Electron Beam Surface Technologies in the Automotive Industry

    Institute of Scientific and Technical Information of China (English)

    Rolf Zenker; Anja Buchwalder

    2004-01-01

    Progress in the beam deflection technique opens up new possibilities for the application of electron beam (EB)surface and welding technologies in the automotive industry. This development is based on three-dimensional high-speed beam deflection and fully automatic online process control. So, in the EB surface treatment three-dimensional energy transfer fields can be realised which take into account the contour of a component, the conditions of heat conduction and the load conditions. High flexibility, precision and reproducibility are typical characteristics. High productivity is achieved by the simultaneous interaction of the EB in several processing areas or by carrying out several processes simultaneously. EB surface treatment is becoming more and more attractive and important especially in the automotive industry, and also in comparison to laser technologies. This paper deals with different EB surface technologies, for example hardening,remelting, surface alloying, dispersing or cladding of different materials such as steel, cast iron and different alloys of Al,Mg and Ti. Examples of applications in the automotive industry, especially engine components, will be discussed.

  1. Simulation of laser beam reflection at the sea surface

    Science.gov (United States)

    Schwenger, Frédéric; Repasi, Endre

    2011-05-01

    A 3D simulation of the reflection of a Gaussian shaped laser beam on the dynamic sea surface is presented. The simulation is suitable for both the calculation of images of SWIR (short wave infrared) imaging sensor and for determination of total detected power of reflected laser light for a bistatic configuration of laser source and receiver at different atmospheric conditions. Our computer simulation comprises the 3D simulation of a maritime scene (open sea/clear sky) and the simulation of laser light reflected at the sea surface. The basic sea surface geometry is modeled by a composition of smooth wind driven gravity waves. The propagation model for water waves is applied for sea surface animation. To predict the view of a camera in the spectral band SWIR the sea surface radiance must be calculated. This is done by considering the emitted sea surface radiance and the reflected sky radiance, calculated by MODTRAN. Additionally, the radiances of laser light specularly reflected at the wind-roughened sea surface are modeled in the SWIR band considering an analytical statistical sea surface BRDF (bidirectional reflectance distribution function). This BRDF model considers the statistical slope statistics of waves and accounts for slope-shadowing of waves that especially occurs at flat incident angles of the laser beam and near horizontal detection angles of reflected irradiance at rough seas. Simulation results are presented showing the variation of the detected laser power dependent on the geometric configuration of laser, sensor and wind characteristics.

  2. Ultralow energy ion beam surface modification of low density polyethylene.

    Science.gov (United States)

    Shenton, Martyn J; Bradley, James W; van den Berg, Jaap A; Armour, David G; Stevens, Gary C

    2005-12-01

    Ultralow energy Ar+ and O+ ion beam irradiation of low density polyethylene has been carried out under controlled dose and monoenergetic conditions. XPS of Ar+-treated surfaces exposed to ambient atmosphere show that the bombardment of 50 eV Ar+ ions at a total dose of 10(16) cm(-2) gives rise to very reactive surfaces with oxygen incorporation at about 50% of the species present in the upper surface layer. Using pure O+ beam irradiation, comparatively low O incorporation is achieved without exposure to atmosphere (approximately 13% O in the upper surface). However, if the surface is activated by Ar+ pretreatment, then large oxygen contents can be achieved under subsequent O+ irradiation (up to 48% O). The results show that for very low energy (20 eV) oxygen ions there is a dose threshold of about 5 x 10(15) cm(-2) before surface oxygen incorporation is observed. It appears that, for both Ar+ and O+ ions in this regime, the degree of surface modification is only very weakly dependent on the ion energy. The results suggest that in the nonequilibrium plasma treatment of polymers, where the ion flux is typically 10(18) m(-2) s(-1), low energy ions (<50 eV) may be responsible for surface chemical modification.

  3. Diamond Processing by Focused Ion Beam - Surface Damage and Recovery

    CERN Document Server

    Bayn, Igal; Cytermann, Catherine; Meyler, Boris; Richter, Vladimir; Salzman, Joseph; Kalish, Rafi

    2011-01-01

    The Nitrogen Vacancy color center (NV-) in diamond is of great interest for novel photonic applications. Diamond nano-photonic structures are often implemented using Focused-Ion-Beam (FIB) processing, leaving a damaged surface which has a detrimental effect on the color center luminescence. The FIB processing effect on single crystal diamond surfaces and their photonic properties is studied by Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and photoluminescence (PL). Exposing the processed surface to hydrogen plasma, followed by chemical etching, drastically decreases implanted Ga concentration, resulting in a recovery of the NV- photo-emission and in a significant increase of the NV-/NV0 ratio.

  4. Chemical reactions on solid surfaces using molecular beam techniques

    Science.gov (United States)

    Palmer, R. L.

    1980-07-01

    Thermal energy molecular beams have been used to study chemical interactions with metal surfaces. Chemisorption of simple molecules such as H2, O2, CH4, C2Hx and CO was investigated on single and polycrystalline surfaces of Pt, Ni, Co, and Ag. Kinetic parameters and reaction mechanisms were determined for model catalytic reactions including CO and C2Hx oxidation and methanation from H2/CO mixtures. Chemical reactions of NOx with CO and D2 on Pt(111) and other surfaces have been surveyed and the kinetics of NO and O2 chemisorption have been measured. The theory of adsorption/desorption kinetics is reviewed and certain deficiencies identified.

  5. Pulsed supersonic molecular beam for characterization of chemically active metal-organic complexes at surfaces

    Science.gov (United States)

    Lear, Amanda M.

    Metal-organic coordination networks (MOCNs) at surfaces consist of a complex of organic ligands bound to an atomic metal center. The MOCNs, when chosen appropriately, can form highly-ordered arrays at surfaces. Ultra-high vacuum surface studies allow control of surface composition and provide 2D growth restrictions, which lead to under-coordinated metal centers. These systems provide an opportunity to tailor the chemical function of the metal centers due to the steric restrictions imposed by the surface. Tuning the adsorption/desorption energy at a metal center and developing a cooperative environment for catalysis are the key scientific questions that motivate the construction of a molecular beam surface analysis system. Characterization of the created systems can be performed utilizing a pulsed supersonic molecular beam (PSMB) in unison with a quadrupole mass spectrometer. A PSMB allows for the highly controlled delivery of reactants with well-defined energy to a given platform making it possible to elucidate detailed chemical tuning information. In this thesis, a summary of prior theoretical molecular beam derivations is provided. Design considerations and an overview of the construction procedure for the current molecular beam apparatus, including initial characterization experiments, are presented. By impinging an Ar beam on a Ag(111) surface, the location of the specular angle (˜65°) and rough sample perimeter coordinates were determined. Additionally, surface analysis experiments, mainly Auger Electron Spectroscopy (AES), were performed to investigate the oxidation of epitaxial graphene on the SiC(0001) surface utilizing an oxygen cracking method. The AES experiments are described in detail and highlight the challenges that were faced when several different graphene samples were used for the oxygen adsorption/desorption experiments.

  6. Frictional and bone ingrowth properties of engineered surface topographies produced by electron beam technology

    NARCIS (Netherlands)

    Biemond, J.E.; Aquarius, R.J.M.; Verdonschot, N.J.J.; Buma, P.

    2011-01-01

    BACKGROUND: Electron beam melting (E-beam) is a new technology to produce 3-dimensional surface topographies for cementless orthopedic implants. METHODS: The friction coefficients of two newly developed E-beam produced surface topographies were in vitro compared with sandblasted E-beam and titanium

  7. Frictional and bone ingrowth properties of engineered surface topographies produced by electron beam technology

    NARCIS (Netherlands)

    Biemond, J. Elizabeth; Aquarius, Rene; Verdonschot, Nicolaas Jacobus Joseph; Buma, Pieter

    2011-01-01

    Background Electron beam melting (E-beam) is a new technology to produce 3-dimensional surface topographies for cementless orthopedic implants. Methods The friction coefficients of two newly developed E-beam produced surface topographies were in vitro compared with sandblasted E-beam and titanium

  8. Ion beam modification of surfaces for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Sommerfeld, Jana

    2014-07-15

    Human life expectancy increased significantly within the last century. Hence, medical care must ever be improved. Optimizing artificial replacements such as hip joints or stents etc. is of special interest. For this purpose, new materials are constantly developed or known ones modified. This work focused on the possibility to change the chemistry and topography of biomedically relevant materials such as diamond-like carbon (DLC) and titanium dioxide (TiO{sub 2}) by means of ion beam irradiation. Mass-separated ion beam deposition was used in order to synthesize DLC layers with a high sp{sup 3} content (> 70%), a sufficiently smooth surface (RMS<1 nm) and a manageable film thickness (50 nm). The chemistry of the DLC layers was changed by ion beam doping with different ion species (Ag,Ti) and concentrations. Additionally, the surface topography of silicon and titanium dioxide was altered by ion beam irradiation under non-perpendicular angle of incidence. The created periodic wave structures (so-called ripples) were characterized and their dependency on the ion energy was investigated. Moreover, ripples on silicon were covered with a thin DLC layer in order to create DLC ripples. The biocompatibility of all samples was investigated by adsorption experiments. For this purpose, human plasma fibrinogen (HPF) was used due to its ambiphilic character, which allows the protein to assume different conformations on materials with different hydrophilicities. Moreover, HPF is a crucial factor in the blood coagulation process. This work comes to the conclusion that the interaction of both, the surface chemistry and topography, has a strong influence on the adsorption behavior of HPF and thus the biocompatibility of a material. Both factors can be specifically tuned by means of ion beam irradiation.

  9. Damage identification in beams by a response surface based technique

    Directory of Open Access Journals (Sweden)

    Teidj S.

    2014-01-01

    Full Text Available In this work, identification of damage in uniform homogeneous metallic beams was considered through the propagation of non dispersive elastic torsional waves. The proposed damage detection procedure consisted of the following sequence. Giving a localized torque excitation, having the form of a short half-sine pulse, the first step was calculating the transient solution of the resulting torsional wave. This torque could be generated in practice by means of asymmetric laser irradiation of the beam surface. Then, a localized defect assumed to be characterized by an abrupt reduction of beam section area with a given height and extent was placed at a known location of the beam. Next, the response in terms of transverse section rotation rate was obtained for a point situated afterwards the defect, where the sensor was positioned. This last could utilize in practice the concept of laser vibrometry. A parametric study has been conducted after that by using a full factorial design of experiments table and numerical simulations based on a finite difference characteristic scheme. This has enabled the derivation of a response surface model that was shown to represent adequately the response of the system in terms of the following factors: defect extent and severity. The final step was performing the inverse problem solution in order to identify the defect characteristics by using measurement.

  10. Ion Beam Textured and Coated Surfaces Experiment (IBEX)

    Science.gov (United States)

    Mirtich, Michael J.; Rutledge, Sharon K.; Stevens, Nicholas; Olle, Raymond; Merrow, James

    1992-01-01

    Ion beam textured and commercial materials suitable for use in space power systems were flown in low Earth orbit on the Long Duration Exposure Facility (LDEF) for 5.8 years. Because of their location on LDEF (98 deg from the ram direction), the 36 materials were primarily exposed to vacuum ultraviolet radiation, thermal cycling, the vacuum of space, the micrometeoroid environment, and grazing incidence atomic oxygen. Measurements of solar absorptance and thermal emittance (pre- and post-flight) showed no changes for almost all of the materials, except for the S-13G and Kapton and coated Kapton samples. The optical property stability of ion beam textured surfaces and most other surfaces indicates that they are functionally durable to the synergistic rigors of the space environment.

  11. Analysis of Asymmetric Piezoelectric Composite Beam

    CERN Document Server

    Chen, J -S; Wu, K -C

    2008-01-01

    This paper deals with the vibration analysis of an asymmetric composite beam composed of glass a piezoelectric material. The Bernoulli's beam theory is adopted for mechanical deformations, and the electric potential field of the piezoelectric material is assumed such that the divergence-free requirement of the electrical displacements is satisfied. The accuracy of the analytic model is assessed by comparing the resonance frequencies obtained by the analytic model with those obtained by the finite element method. The model developed can be used as a tool for designing piezoelectric actuators such as micro-pumps.

  12. Simulation based analysis of laser beam brazing

    Science.gov (United States)

    Dobler, Michael; Wiethop, Philipp; Schmid, Daniel; Schmidt, Michael

    2016-03-01

    Laser beam brazing is a well-established joining technology in car body manufacturing with main applications in the joining of divided tailgates and the joining of roof and side panels. A key advantage of laser brazed joints is the seam's visual quality which satisfies highest requirements. However, the laser beam brazing process is very complex and process dynamics are only partially understood. In order to gain deeper knowledge of the laser beam brazing process, to determine optimal process parameters and to test process variants, a transient three-dimensional simulation model of laser beam brazing is developed. This model takes into account energy input, heat transfer as well as fluid and wetting dynamics that lead to the formation of the brazing seam. A validation of the simulation model is performed by metallographic analysis and thermocouple measurements for different parameter sets of the brazing process. These results show that the multi-physical simulation model not only can be used to gain insight into the laser brazing process but also offers the possibility of process optimization in industrial applications. The model's capabilities in determining optimal process parameters are exemplarily shown for the laser power. Small deviations in the energy input can affect the brazing results significantly. Therefore, the simulation model is used to analyze the effect of the lateral laser beam position on the energy input and the resulting brazing seam.

  13. Mechanical and tribological properties of ion beam-processed surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kodali, Padma [Univ. of Maryland, College Park, MD (United States)

    1998-01-01

    The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation; (2) characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation; and (3) developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. DLC coatings have low friction, low wear factor, and high hardness. The fracture toughness of DLC coatings has been estimated for the first time. The wear mechanism in DLC coatings investigated with a ruby slider under a contact stress of 1 GPa was determined to be plastic deformation. The preliminary data on metastable BCN compound coatings indicated high friction, low wear factor, and high hardness.

  14. Structural dynamic analysis of composite beams

    Science.gov (United States)

    Suresh, J. K.; Venkatesan, C.; Ramamurti, V.

    1990-12-01

    In the treatment of the structural dynamic problem of composite materials, two alternate types of formulations, based on the elastic modulus and compliance quantities, exist in the literature. The definitions of the various rigidities are observed to differ in these two approaches. Following these two types of formulation, the structural dynamic characteristics of a composite beam are analyzed. The results of the analysis are compared with those available in the literature. Based on the comparison, the influence of the warping function in defining the coupling terms in the modulus approach and also on the natural frequencies of the beam has been identified. It is found from the analysis that, in certain cases, the difference between the results of the two approaches is appreciable. These differences may be attributed to the constraints imposed on the deformation and flexibility of the beam by the choice of the description of the warping behaviour. Finally, the influence of material properties on the structural dynamic characteristics of the beam is studied for different composites for various angles of orthotropy.

  15. Biomimetic surface structuring using cylindrical vector femtosecond laser beams

    Science.gov (United States)

    Skoulas, Evangelos; Manousaki, Alexandra; Fotakis, Costas; Stratakis, Emmanuel

    2017-03-01

    We report on a new, single-step and scalable method to fabricate highly ordered, multi-directional and complex surface structures that mimic the unique morphological features of certain species found in nature. Biomimetic surface structuring was realized by exploiting the unique and versatile angular profile and the electric field symmetry of cylindrical vector (CV) femtosecond (fs) laser beams. It is shown that, highly controllable, periodic structures exhibiting sizes at nano-, micro- and dual- micro/nano scales can be directly written on Ni upon line and large area scanning with radial and azimuthal polarization beams. Depending on the irradiation conditions, new complex multi-directional nanostructures, inspired by the Shark’s skin morphology, as well as superhydrophobic dual-scale structures mimicking the Lotus’ leaf water repellent properties can be attained. It is concluded that the versatility and features variations of structures formed is by far superior to those obtained via laser processing with linearly polarized beams. More important, by exploiting the capabilities offered by fs CV fields, the present technique can be further extended to fabricate even more complex and unconventional structures. We believe that our approach provides a new concept in laser materials processing, which can be further exploited for expanding the breadth and novelty of applications.

  16. SU-E-T-577: Obliquity Factor and Surface Dose in Proton Beam Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Das, I; Andersen, A [Indiana University- School of Medicine, Indianapolis, IN (United States); Coutinho, L [Procure Proton Therapy Center, Somerset, NJ (United States)

    2015-06-15

    Purpose: The advantage of lower skin dose in proton beam may be diminished creating radiation related sequalae usually seen with photon and electron beams. This study evaluates the surface dose as a complex function of beam parameters but more importantly the effect of beam angle. Methods: Surface dose in proton beam depends on the beam energy, source to surface distance, the air gap between snout and surface, field size, material thickness in front of surface, atomic number of the medium, beam angle and type of nozzle (ie double scattering, (DS), uniform scanning (US) or pencil beam scanning (PBS). Obliquity factor (OF) is defined as ratio of surface dose in 0° to beam angle Θ. Measurements were made in water phantom at various beam angles using very small microdiamond that has shown favorable beam characteristics for high, medium and low proton energy. Depth dose measurements were performed in the central axis of the beam in each respective gantry angle. Results: It is observed that surface dose is energy dependent but more predominantly on the SOBP. It is found that as SSD increases, surface dose decreases. In general, SSD, and air gap has limited impact in clinical proton range. High energy has higher surface dose and so the beam angle. The OF rises with beam angle. Compared to OF of 1.0 at 0° beam angle, the value is 1.5, 1.6, 1,7 for small, medium and large range respectively for 60 degree angle. Conclusion: It is advised that just like range and SOBP, surface dose should be clearly understood and a method to reduce the surface dose should be employed. Obliquity factor is a critical parameter that should be accounted in proton beam therapy and a perpendicular beam should be used to reduce surface dose.

  17. Rapid Process to Generate Beam Envelopes for Optical System Analysis

    Science.gov (United States)

    Howard, Joseph; Seals, Lenward

    2012-01-01

    The task of evaluating obstructions in the optical throughput of an optical system requires the use of two disciplines, and hence, two models: optical models for the details of optical propagation, and mechanical models for determining the actual structure that exists in the optical system. Previous analysis methods for creating beam envelopes (or cones of light) for use in this obstruction analysis were found to be cumbersome to calculate and take significant time and resources to complete. A new process was developed that takes less time to complete beam envelope analysis, is more accurate and less dependent upon manual node tracking to create the beam envelopes, and eases the burden on the mechanical CAD (computer-aided design) designers to form the beam solids. This algorithm allows rapid generation of beam envelopes for optical system obstruction analysis. Ray trace information is taken from optical design software and used to generate CAD objects that represent the boundary of the beam envelopes for detailed analysis in mechanical CAD software. Matlab is used to call ray trace data from the optical model for all fields and entrance pupil points of interest. These are chosen to be the edge of each space, so that these rays produce the bounding volume for the beam. The x and y global coordinate data is collected on the surface planes of interest, typically an image of the field and entrance pupil internal of the optical system. This x and y coordinate data is then evaluated using a convex hull algorithm, which removes any internal points, which are unnecessary to produce the bounding volume of interest. At this point, tolerances can be applied to expand the size of either the field or aperture, depending on the allocations. Once this minimum set of coordinates on the pupil and field is obtained, a new set of rays is generated between the field plane and aperture plane (or vice-versa). These rays are then evaluated at planes between the aperture and field, at a

  18. Micro-Shaping of Nanopatterned Surfaces by Electron Beam Irradiation

    Directory of Open Access Journals (Sweden)

    Carlos Angulo Barrios

    2016-04-01

    Full Text Available We show that planar nanopatterned thin films on standard polycarbonate (PC compact discs (CD can be micro-shaped in a non-contact manner via direct e-beam exposure. The shape of the film can be controlled by proper selection of the e-beam parameters. As an example of application, we demonstrate a two-dimensional (2D array of micro-lenses/reservoirs conformally covered by an Al 2D nanohole array (NHA film on a PC CD substrate. It is also shown that such a curvilinear Al NHA layer can be easily transferred onto a flexible polymeric support. The presented technique provides a new tool for creating lab-on-CD architectures and developing multifunctional (flexible non-planar nanostructured films and surfaces.

  19. Quantitative Hydrocarbon Surface Analysis

    Science.gov (United States)

    Douglas, Vonnie M.

    2000-01-01

    The elimination of ozone depleting substances, such as carbon tetrachloride, has resulted in the use of new analytical techniques for cleanliness verification and contamination sampling. The last remaining application at Rocketdyne which required a replacement technique was the quantitative analysis of hydrocarbons by infrared spectrometry. This application, which previously utilized carbon tetrachloride, was successfully modified using the SOC-400, a compact portable FTIR manufactured by Surface Optics Corporation. This instrument can quantitatively measure and identify hydrocarbons from solvent flush of hardware as well as directly analyze the surface of metallic components without the use of ozone depleting chemicals. Several sampling accessories are utilized to perform analysis for various applications.

  20. Investigation of plasma–surface interaction at plasma beam facilities

    Energy Technology Data Exchange (ETDEWEB)

    Kurnaev, V., E-mail: kurnaev@plasma.mephi.ru [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Vizgalov, I.; Gutorov, K. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Tulenbergenov, T.; Sokolov, I.; Kolodeshnikov, A.; Ignashev, V.; Zuev, V.; Bogomolova, I. [Institute of Atomic Energy, National Nuclear Center the Republic of Kazakhstan, Street Krasnoarmejsky, 10, 071100 Kurchatov (Kazakhstan); Klimov, N. [SRC RF TRINITI, ul. Pushkovykh, vladenie 12, Troitsk, 142190 Moscow (Russian Federation)

    2015-08-15

    The new Plasma Beam Facility (PBF) has been put into operation for assistance in testing of plasma faced components at Material Science Kazakhstan Tokamak (KTM). PBF includes a powerful electron gun (up to 30 kV, 1 A) and a high vacuum chamber with longitudinal magnetic field coils (up to 0.2 T). The regime of high vacuum electron beam transportation is used for thermal tests with power density at the target surface up to 10 GW/m{sup 2}. The beam plasma discharge (BPD) regime with a gas-puff is used for generation of intensive ion fluxes up to 3 ⋅ 10{sup 22} m{sup −2} s{sup −1}. Initial tests of the KTM PBF’s capabilities were carried out: various discharge regimes, carbon deposits cleaning, simultaneous thermal and ion impacts on radiation cooled refractory targets. With a water-cooled target the KTM PBF could be used for high heat flux tests of materials (validated by the experiment with W mock-up at the PR-2 PBF)

  1. Vibration Analysis of Timoshenko Beams on a Nonlinear Elastic Foundation

    Institute of Scientific and Technical Information of China (English)

    MO Yihua; OU Li; ZHONG Hongzhi

    2009-01-01

    The vibrations of beams on a nonlinear elastic foundation were analyzed considering the effects of transverse shear deformation and the rotational inertia of beams. A weak form quadrature element method (QEM) is used for the vibration analysis. The fundamental frequencies of beams are presented for various slenderness ratios and nonlinear foundation parameters for both slender and short beams. The results for slender beams compare well with finite element results. The analysis shows that the transverse shear de-formation and the nonlinear foundation parameter significantly affect the fundamental frequency of the beams.

  2. Improvement of carbon fiber surface properties using electron beam irradiation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Carbon fiber-reinforced advance composites have been used for struetural applications, mainly on account of their mechanical properties. The main factor for a good mechanical performance of carbon fiber-reinforced composite is the interfacial interaction between its components, which are carbon fiber and polymeric matrix. The aim of this study is to improve the surface properties of the carbon fiber using ionizing radiation from an electron beam to obtain better adhesion properties in the resultant composite. EB radiation was applied on the carbon fiber itself before preparing test specimens for the mechanical tests. Experimental results showed that EB irradiation improved the tensile strength of carbon fiber samples. The maximum value in tensile strength was reached using doses of about 250kGy. After breakage, the morphology aspect of the tensile specimens prepared with irradiated and non-irradiated carbon fibers were evaluated. SEM micrographs showed modifications on the carbon fiber surface.

  3. Surface dose with grids in electron beam radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Lin, K.-H.; Huang, C.-Y.; Lin, J.-P.; Chu, T.-C. E-mail: tcchu@mx.nthu.edu.tw

    2002-03-01

    This investigation attempts to solve the problem of the lack of skin-sparing effect in electron radiation therapy and to increase the tolerance of skin to radiation using the grid technique. Electron grid therapy involves the mounting of a Cerrobend grid in the electron cone. Film dosimetry was employed to measure the relative surface dose and the percentage depth dose profile of electron grid portals. Various grid hole diameters (d=0.45, 1.0, 1.5 cm) and grid hole spacings (s=0.4, 0.2 cm) were considered for electron beams from 6 to 14 MeV. Experimental results indicate that the electron grid technique can reduce the relative surface dose in electron radiation therapy. Degradations of the relative surface dose depend on the percentage of open area in the grid portal. A proper grid design allows the surface dose to be reduced and the range of nonhomogeneous doses to be limited to a depth at which the target volume can receive a homogeneous dose. The grid technique can lower the surface dose in electron radiation therapy.

  4. Surface Aesthetics and Analysis.

    Science.gov (United States)

    Çakır, Barış; Öreroğlu, Ali Rıza; Daniel, Rollin K

    2016-01-01

    Surface aesthetics of an attractive nose result from certain lines, shadows, and highlights with specific proportions and breakpoints. Analysis emphasizes geometric polygons as aesthetic subunits. Evaluation of the complete nasal surface aesthetics is achieved using geometric polygons to define the existing deformity and aesthetic goals. The relationship between the dome triangles, interdomal triangle, facet polygons, and infralobular polygon are integrated to form the "diamond shape" light reflection on the nasal tip. The principles of geometric polygons allow the surgeon to analyze the deformities of the nose, define an operative plan to achieve specific goals, and select the appropriate operative technique.

  5. Morphological change of self-organized protrusions of fluoropolymer surface by ion beam irradiation

    Science.gov (United States)

    Kitamura (Ogawa), Akane; Kobayashi, Tomohiro; Satoh, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Suzuki, Akihiro; Terai, Takayuki

    2013-07-01

    Polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP) are typical fluoropolymers displaying several desirable technological properties such as electrical insulation and high chemical resistance. When their surfaces are irradiated with ion beams, dense micro-protrusions formed after the emergence and spread of micropores across the entire irradiated area, allowing culture cells to spread on the top of the protrusions. In this study, we investigate the morphological changes introduced in the fluoropolymer surfaces by ion beams as the energy of the beams is increased. When an FEP sample was irradiated with a nitrogen ion beam with an energy of less than 350 keV at 1.0 μA/cm2, protrusions were formed with a density between 2 × 107/cm2 and 2 × 108/cm2. However, at energies higher than 350 keV, the protrusions became sparse, and the density dropped to 5 × 102/cm2. Protrusions appeared sporadically during irradiation at high energies, and the top of the protrusions appeared as spots inside the sample, which were difficult to etch and became elongated as the erosion of the surface progressed. Erosion was caused by sputtering of FEP molecules and evaporation at notably elevated temperatures on the surface. Analysis based on attenuated total reflectance/Fourier transform infrared spectroscopy showed the presence of Cdbnd C bonds as well as -COOH, -Cdbnd O, and -OH bonds on all irradiated samples. Their concentration on the surface densely covered with micro-protrusions was higher than that on the surface with sparse protrusions after irradiation at energies exceeding 350 keV. Thus, we determined a suitable range for the ion energy for creating FEP surfaces densely covered with protrusions.

  6. Morphological change of self-organized protrusions of fluoropolymer surface by ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Akane, E-mail: ogawa.akane@jaea.go.jp [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Kobayashi, Tomohiro [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 350-0198 (Japan); Satoh, Takahiro; Koka, Masashi; Kamiya, Tomihiro [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Suzuki, Akihiro; Terai, Takayuki [Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2013-07-15

    Polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP) are typical fluoropolymers displaying several desirable technological properties such as electrical insulation and high chemical resistance. When their surfaces are irradiated with ion beams, dense micro-protrusions formed after the emergence and spread of micropores across the entire irradiated area, allowing culture cells to spread on the top of the protrusions. In this study, we investigate the morphological changes introduced in the fluoropolymer surfaces by ion beams as the energy of the beams is increased. When an FEP sample was irradiated with a nitrogen ion beam with an energy of less than 350 keV at 1.0 μA/cm{sup 2}, protrusions were formed with a density between 2 × 10{sup 7}/cm{sup 2} and 2 × 10{sup 8}/cm{sup 2}. However, at energies higher than 350 keV, the protrusions became sparse, and the density dropped to 5 × 10{sup 2}/cm{sup 2}. Protrusions appeared sporadically during irradiation at high energies, and the top of the protrusions appeared as spots inside the sample, which were difficult to etch and became elongated as the erosion of the surface progressed. Erosion was caused by sputtering of FEP molecules and evaporation at notably elevated temperatures on the surface. Analysis based on attenuated total reflectance/Fourier transform infrared spectroscopy showed the presence of C=C bonds as well as –COOH, –C=O, and –OH bonds on all irradiated samples. Their concentration on the surface densely covered with micro-protrusions was higher than that on the surface with sparse protrusions after irradiation at energies exceeding 350 keV. Thus, we determined a suitable range for the ion energy for creating FEP surfaces densely covered with protrusions.

  7. Formation of the surface alloys by high-intensity pulsed electron beam irradiation of the coating/substrate system

    Science.gov (United States)

    Ivanov, Yu F.; Petrikova, E. A.; Teresov, A. D.; Krysina, O. V.; Rygina, M. E.

    2015-04-01

    The results of the analysis of the structure and properties of the surface layer of aluminum A7 subjected to alloying by the intense pulsed electron beam melting of the film / substrate system. Fold increase in strength and tribological properties of the modified surface layer due to the formation of submicro - nanoscale multiphase structure have been revealed.

  8. An Analysis for Cross Beam-Ground Anchor Reinforcement

    Institute of Scientific and Technical Information of China (English)

    Xu Yingzi; Zhang Baiqing; Tang Huiming

    2005-01-01

    With the rapid development of water facilities, hydroelectric projects, highways and railways in China, beam-anchor reinforcement has been widely used to stabilize slopes in recent years. But the theory for the design of beam-anchor reinforcement is far behind the application. Cross beam-ground anchor reinforcement is a combination of beams and anchors forming a new structure to prevent slope sliding. The forces in the beams are discussed using theoretical analysis and numerical modeling. The Winkler model is used to analyze the beams, and reasonable values of λ, length, spacing and cantilevered length for the beams are determined through a theoretical analysis. A three-dimensional finite element method is adopted to model the interaction of the beams and soils and a structure analysis is applied to treat the beams and to study the stress distribution in external and internal beams. The analytical results show that it is better to satisfy λ≥2π, the spacing between anchors ls should be lsλ<π/2 and cantilever length should be (0.3-0.5)ls for the optimum design. The numerical results show that the same design can be used for all beams in different directions, including the internal and external beams. The application of the analytical method for reinforcement beam analysis is acceptable. It is better to choose a safety coefficient of 1.3 for design based on the analytical method for safety.

  9. LEEM investigations of clean surfaces driven by energetic ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Abbamonte, Peter M. [University of Illinois

    2013-04-24

    The original purpose of this award was to use low‐energy electron microscopy (LEEM) to explore the dynamics of surfaces of clean single crystal surfaces when driven by a beam of energetic ions. The goal was to understand the nanoscience of hyperthermal growth, surface erosion by sublimation and irradiation, operation of surface sinks in irradiated materials, diffusion on driven surfaces, and the creation of structural patterns. This project was based on a novel LEEM system constructed by C. P. Flynn, which provided real‐time imaging of surface dynamics by scattering low energy electrons. With the passing of Prof. Flynn in late 2011, this project was completed under a slightly different scope by constructing a low‐energy, inelastic electron scattering (EELS) instrument. Consistent with Flynn's original objectives for his LEEM system, this device probes the dynamics of crystal surfaces. However the measurements are not carried out in real time, but instead are done in the frequency domain, through the energy lost from the probe electrons. The purpose of this device is to study the collective bosonic excitations in a variety of materials, including high temperature superconductors, topological insulators, carbon allotropes including (but not limited to) graphene, etc. The ultimate goal here is to identify the bosons that mediate interactions in these and other materials, with hopes of shedding light on the origin of many exotic phenomena including high temperature superconductivity. We completed the construction of a low‐energy EELS system that operates with an electron kinetic energy of 7 - 10 eV. With this instrument now running, we hope to identify, among other things, the bosons that mediate pairing in high temperature superconductors. Using this instrument, we have already made our first discovery. Studying freshly cleaved single crystals of Bi{sub 2}Se{sub 3}, which is a topological insulator, we have observed a surface excitation at an energy loss

  10. Bellerophon Environment for Analysis of Materials (BEAM)

    Energy Technology Data Exchange (ETDEWEB)

    2017-01-08

    Improvements in scientific instrumentation allow imaging at mesoscopic to atomic length scales, many spectroscopic modes, and now--with the rise of multimodal acquisition systems and the associated processing capability--the era of multidimensional, informationally dense data sets has arrived. Technical issues in these combinatorial scientific fields are exacerbated by computational challenges best summarized as a necessity for drastic improvement in the capability to transfer, store, and analyze large volumes of data. The Bellerophon Environment for Analysis of Materials (BEAM) platform provides material scientists the capability to directly leverage the integrated computational and analytical power of High Performance Computing (HPC) to perform scalable data analysis and simulation and manage uploaded data files via an intuitive, cross-platform client user interface. This framework delivers authenticated, "push-button" execution of complex user workflows that deploy data analysis algorithms and computational simulations utilizing compute-and-data cloud infrastructures and HPC environments like Titan at the Oak Ridge Leadershp Computing Facility (OLCF).

  11. Analysis of reinforced concrete beams by the equivalent section method

    CERN Document Server

    Schulz, Mauro

    2014-01-01

    This research investigates the analysis of reinforced concrete beams subjected to combined axial load, bending moment and shear force. Cross-sections of general shape are divided, along the height, into plane elements. The biaxial behavior is represented according to the smeared rotating crack approach. Using traditionally accepted hypotheses for beams, the shear flow is determined by applying the Jouravski formula to an "equivalent section", which takes into account the nonlinear material behavior. The "Equivalent Section Method", originally proposed by Diaz (1980) and Diaz and Schulz (1981), is improved and simplified. The formulation is implemented applying the bidimensional constitutive model A, proposed by Vecchio and Collins (1993). The tension-stiffening effect is considered as adopted by Polak and Vecchio (1993). Shear slip at crack surfaces, Poisson's ratio and other secondary effects are not considered. Validation is undertaken by comparison with experimental results obtained by other researchers. T...

  12. Analysis of beam loss induced abort kicker instability

    Energy Technology Data Exchange (ETDEWEB)

    Zhang W.; Sandberg, J.; Ahrens, L.; Fischer, W.; Hahn, H.; Mi, J.; Pai, C.; Tan, Y.

    2012-05-20

    Through more than a decade of operation, we have noticed the phenomena of beam loss induced kicker instability in the RHIC beam abort systems. In this study, we analyze the short term beam loss before abort kicker pre-fire events and operation conditions before capacitor failures. Beam loss has caused capacitor failures and elevated radiation level concentrated at failed end of capacitor has been observed. We are interested in beam loss induced radiation and heat dissipation in large oil filled capacitors and beam triggered thyratron conduction. We hope the analysis result would lead to better protection of the abort systems and improved stability of the RHIC operation.

  13. Stability Analysis of Nonuniform Rectangular Beams Using Homotopy Perturbation Method

    Directory of Open Access Journals (Sweden)

    Seval Pinarbasi

    2012-01-01

    Full Text Available The design of slender beams, that is, beams with large laterally unsupported lengths, is commonly controlled by stability limit states. Beam buckling, also called “lateral torsional buckling,” is different from column buckling in that a beam not only displaces laterally but also twists about its axis during buckling. The coupling between twist and lateral displacement makes stability analysis of beams more complex than that of columns. For this reason, most of the analytical studies in the literature on beam stability are concentrated on simple cases: uniform beams with ideal boundary conditions and simple loadings. This paper shows that complex beam stability problems, such as lateral torsional buckling of rectangular beams with variable cross-sections, can successfully be solved using homotopy perturbation method (HPM.

  14. Shape Error Analysis of Functional Surface Based on Isogeometrical Approach

    Science.gov (United States)

    YUAN, Pei; LIU, Zhenyu; TAN, Jianrong

    2017-05-01

    The construction of traditional finite element geometry (i.e., the meshing procedure) is time consuming and creates geometric errors. The drawbacks can be overcame by the Isogeometric Analysis (IGA), which integrates the computer aided design and structural analysis in a unified way. A new IGA beam element is developed by integrating the displacement field of the element, which is approximated by the NURBS basis, with the internal work formula of Euler-Bernoulli beam theory with the small deformation and elastic assumptions. Two cases of the strong coupling of IGA elements, "beam to beam" and "beam to shell", are also discussed. The maximum relative errors of the deformation in the three directions of cantilever beam benchmark problem between analytical solutions and IGA solutions are less than 0.1%, which illustrate the good performance of the developed IGA beam element. In addition, the application of the developed IGA beam element in the Root Mean Square (RMS) error analysis of reflector antenna surface, which is a kind of typical functional surface whose precision is closely related to the product's performance, indicates that no matter how coarse the discretization is, the IGA method is able to achieve the accurate solution with less degrees of freedom than standard Finite Element Analysis (FEA). The proposed research provides an effective alternative to standard FEA for shape error analysis of functional surface.

  15. Surface analysis in microelectronics.

    Science.gov (United States)

    Pignataro, S

    1995-10-01

    The contribution given by surface analysis to solve some problems encountered in the production of electronic power devices have been discussed. Mainly two types of problems have been faced. One of these deal with interfacial chemistry. Three examples have been investigated. The first applies to the improvement of the quality and the reliability of plastic packages through the optimization of the resin/metal and resin/die adhesion. The second relies to the adhesion between polyimide and silicon nitride used in the multilevel technology. The third example refers to the so called die-attach process and related problems. Another area of interest in microelectronics is that of the erosion of various types of surfaces and the possibility of wrong etching. A few examples of the application of surface analytical techniques for these problems will be presented. XPS and SIMS working in imaging and multipoint analysis mode, scanning acoustic microscopy, contact angle measurements as well as peeling and tensile strength measurements are the main tools used to obtain useful data.

  16. Surface modification of Ti alloy by electro-explosive alloying and electron-beam treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gromov, Victor, E-mail: gromov@physics.sibsiu.ru; Kobzareva, Tatiana, E-mail: kobzarevatanya@mail.ru; Budovskikh, Evgeniy, E-mail: budovskih-ea@physics.sibsiu.ru; Baschenko, Lyudmila, E-mail: gromov@physics.sibsiu.ru [Siberian State Industrial University, 42, Kirov Str., Novokuznetsk, 654007 (Russian Federation); Ivanov, Yuryi, E-mail: yufi55@mail.ru [Institute of High Current Electronics SB RAS, 4, Akademicheskii Av. Tomsk, 634055 (Russian Federation); National Research Tomsk State University, 30, Lenina Av. Tomsk, 634034 (Russian Federation)

    2016-01-15

    By methods of modern physical metallurgy the analysis of structure phase states of titanium alloy VT6 is carried out after electric explosion alloying with boron carbide and subsequent irradiation by pulsed electron beam. The formation of an electro-explosive alloying zone of a thickness up to 50 µm, having a gradient structure, characterized by decrease in the concentration of carbon and boron with increasing distance to the treatable surface has been revealed. Subsequent electron-beam treatment of alloying zone leads to smoothing of the alloying area surface and is accompanied by the multilayer structure formation at the depth of 30 µm with alternating layers with different alloying degrees having the structure of submicro - and nanoscale level.

  17. Surface modification of Ti alloy by electro-explosive alloying and electron-beam treatment

    Science.gov (United States)

    Gromov, Victor; Kobzareva, Tatiana; Ivanov, Yuryi; Budovskikh, Evgeniy; Baschenko, Lyudmila

    2016-01-01

    By methods of modern physical metallurgy the analysis of structure phase states of titanium alloy VT6 is carried out after electric explosion alloying with boron carbide and subsequent irradiation by pulsed electron beam. The formation of an electro-explosive alloying zone of a thickness up to 50 µm, having a gradient structure, characterized by decrease in the concentration of carbon and boron with increasing distance to the treatable surface has been revealed. Subsequent electron-beam treatment of alloying zone leads to smoothing of the alloying area surface and is accompanied by the multilayer structure formation at the depth of 30 µm with alternating layers with different alloying degrees having the structure of submicro - and nanoscale level.

  18. Hydrodynamic approach to surface pattern formation by ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Mario, E-mail: marioc@upcomillas.es [Grupo Interdisciplinar de Sistemas Complejos (GISC) and Grupo de Dinamica No Lineal (DNL), Escuela Tecnica Superior de Ingenieri a - ICAI, Universidad Pontificia Comillas, E-28015 Madrid (Spain); Cuerno, Rodolfo [Departamento de Matematicas and GISC, Universidad Carlos III de Madrid, Avenida de la Universidad 30, E-28911 Leganes (Spain)

    2012-02-15

    On the proper timescale, amorphous solids can flow. Solid flow can be observed macroscopically in glaciers or lead pipes, but it can also be artificially enhanced by creating defects. Ion Beam Sputtering (IBS) is a technique in which ions with energies in the 0.110 keV range impact against a solid target inducing defect creation and dynamics, and eroding its surface leading to formation of ordered nanostructures. Despite its technological interest, a basic understanding of nanopattern formation processes occurring under IBS of amorphizable targets has not been clearly established, recent experiments on Si having largely questioned knowledge accumulated during the last two decades. A number of interfacial equations have been proposed in the past to describe these phenomena, typically by adding together different contributions coming from surface diffusion, ion sputtering or mass redistribution, etc. in a non-systematic way. Here, we exploit the general idea of solids flowing due to ion impacts in order to establish a general framework into which different mechanisms (such as viscous flow, stress, diffusion, or sputtering) can be incorporated, under generic physical conservation laws. As opposed to formulating phenomenological interfacial equations, this approach allows to assess systematically the relevance and interplay of different physical mechanisms influencing surface pattern formation by IBS.

  19. EXACT ANALYSIS OF WAVE PROPAGATION IN AN INFINITE RECTANGULAR BEAM

    Institute of Scientific and Technical Information of China (English)

    孙卫明; 杨光松; 李东旭

    2004-01-01

    The Fourier series method was extended for the exact analysis of wave propagation in an infinite rectangular beam. Initially, by solving the three-dimensional elastodynamic equations a general analytic solution was derived for wave motion within the beam. And then for the beam with stress-free boundaries, the propagation characteristics of elastic waves were presented. This accurate wave propagation model lays a solid foundation of simultaneous control of coupled waves in the beam.

  20. Analysis of transmission efficiency of SSRF electron beam transfer lines

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this article, the main factors which influence transmission efficiency of the SSRF electron beam transfer lines are described, including physical requirements for magnet system, vacuum system, beam diagnostic system,trajectory correction system, etc. The dynamic simulation calculation and transmission efficiency analysis of the SSRF electron beam transfer lines are presented, and the studies show that the design purpose of efficient beam transmission and injection will be achieved.

  1. Ion beam figuring of high-slope surfaces based on figure error compensation algorithm.

    Science.gov (United States)

    Dai, Yifan; Liao, Wenlin; Zhou, Lin; Chen, Shanyong; Xie, Xuhui

    2010-12-01

    In a deterministic figuring process, it is critical to guarantee high stability of the removal function as well as the accuracy of the dwell time solution, which directly influence the convergence of the figuring process. Hence, when figuring steep optics, the ion beam is required to keep a perpendicular incidence, and a five-axis figuring machine is typically utilized. In this paper, however, a method for high-precision figuring of high-slope optics is proposed with a linear three-axis machine, allowing for inclined beam incidence. First, the changing rule of the removal function and the normal removal rate with the incidence angle is analyzed according to the removal characteristics of ion beam figuring (IBF). Then, we propose to reduce the influence of varying removal function and projection distortion on the dwell time solution by means of figure error compensation. Consequently, the incident ion beam is allowed to keep parallel to the optical axis. Simulations and experiments are given to verify the removal analysis. Finally, a figuring experiment is conducted on a linear three-axis IBF machine, which proves the validity of the method for high-slope surfaces. It takes two iterations and about 9 min to successfully figure a fused silica sample, whose aperture is 21.3 mm and radius of curvature is 16 mm. The root-mean-square figure error of the convex surface is reduced from 13.13 to 5.86 nm.

  2. Molecular beam photoionization and gas-surface scattering

    Energy Technology Data Exchange (ETDEWEB)

    Ceyer, S.T.

    1979-09-01

    The energetics of the ethylene ion-molecule reactions was investigated in more detail than previously possible in two body collision experiments by photoionization of the neutral van der Waals ethylene dimer. The stability of the (C/sub 2/H/sub 4/)/sup +/C/sub 2/H/sub 4/ ion-molecule collision complex has been determined to be 18.2 +- 0.5 kcal. The highest potential barriers along the reaction coordinate for decomposition of this collision complex into C/sub 4/H/sub 7//sup +/ + H and C/sub 3/H/sub 5//sup +/ + CH/sub 3/ have been determined to be 0 +- 1.5 and 8.7 +- 1.5 kcal. In a similar manner, the energetics of the solvated ethylene dimer ion was investigated by the photoionization of the ethylene trimer. The absolute proton affinity of NH/sub 3/ (203.6 +- 1.3 kcal/mole) and the proton solvation energies by more than one NH/sub 3/ have been determined by molecular beam photoionization. In addition, the NH/sub 3//sup +/-NH/sub 3/ interaction energy (0.79 +- 0.05 eV) was measured by photoionization of the neutral van der Waals dimer. These experiments have shown that photoionization of van der Waals clusters is a very powerful method of determining the energetics of gas phase proton solvation. The scattering of helium atomic beams from a high Miller index platinum surface that exhibits ordered, periodic steps on the atomic scale to probe the effect of atomic steps on the scattering distribution is explored. Rainbow scattering is observed when the step edges are perpendicular to the incident helium atoms. The design, construction and operation of a beam-surface scattering apparatus are described. The first data obtained in this apparatus are presented and the interesting dynamical aspects of the oxidation of D, D/sub 2/ and CO are discussed. 75 references.

  3. Development of hydrophobicity of mica surfaces by ion beam sputtering

    Science.gov (United States)

    Metya, Amaresh; Ghose, Debabrata; Ray, Nihar Ranjan

    2014-02-01

    The hydrophilic mica surface can be made hydrophobic by low energy Ar+ ion sputtering. The ion sputtering leads to both topographical and physicochemical changes of the surface which are thought to be responsible for the water repelling behavior. The sessile drop method is used to evaluate the wetting properties of the sputtered mica surfaces. It has been shown that the sputter-pattern at the nano-length scale has little influence on the development of hydrophobicity. On the other hand, the wettability appears to be strongly connected with the chemistry of the bombarded surface. We have also studied the temporal evolution of contact angle as the water evaporates due to difference in vapor pressures between the droplet surface and the surroundings. The analysis offers a simple method to estimate the diffusion coefficient of water vapor.

  4. Development of hydrophobicity of mica surfaces by ion beam sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Metya, Amaresh; Ghose, Debabrata, E-mail: debabrata.ghose@saha.ac.in; Ray, Nihar Ranjan

    2014-02-28

    The hydrophilic mica surface can be made hydrophobic by low energy Ar{sup +} ion sputtering. The ion sputtering leads to both topographical and physicochemical changes of the surface which are thought to be responsible for the water repelling behavior. The sessile drop method is used to evaluate the wetting properties of the sputtered mica surfaces. It has been shown that the sputter-pattern at the nano-length scale has little influence on the development of hydrophobicity. On the other hand, the wettability appears to be strongly connected with the chemistry of the bombarded surface. We have also studied the temporal evolution of contact angle as the water evaporates due to difference in vapor pressures between the droplet surface and the surroundings. The analysis offers a simple method to estimate the diffusion coefficient of water vapor.

  5. Theoretical analysis of some problems in the measurement of beam divergence angle for EAST neutral beam injector

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Beam angular divergence is one of the indicators to evaluate the beam quality. Operating parameters of the beam extraction system could be adjusted to gain better beam quality following the measurement results, which will be helpful not only to study the transmission characteristics of the beam and the power distribution on the heat load components, but also to understand the real-time working condition of the ion source and beam extraction system. This study includes: (1) the theoretical analysis of beam extraction pulse duration for measurement of beam angular divergence; (2) the theoretical analysis of beam intensity distribution during beam transmission for Experimental Advanced Superconducting Tokomak (EAST) neutral beam injector. Those theoretical analyses could point the way to the measurement of beam divergence angle for EAST neutral beam injector.

  6. Analysis of beam envelope by transverse space charge effect

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, Shin`ichi [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1997-09-01

    It is important for high current accelerators to estimate the contribution of the space charge effect to keep the beam off its beak up. The application of an envelope equation is examined in previous report in which the beam is just coasting beam (non accelerating). The analysis of space charge effect is necessary for the comparison in coming accelerator test in PNC. In order to evaluate the beam behavior in high current, the beam dynamics and beam parameters which are input to the equation for the evaluation are developed and make it ready to estimate the beam transverse dynamics by the space charge. The estimate needs to have enough accuracy for advanced code calculation. After the preparation of the analytic expression of transverse motion, the non-linear differential equation of beam dynamics is solved by a numerical method on a personal computer. The beam envelope from the equation is estimated by means of the beam emittance, current and energy. The result from the analysis shows that the transverse beam broadening is scarecely small around the beam current value of PNC design. The contribution to the beam broadening of PNC linac comes from its beam emittance. The beam broadening in 100 MeV case is almost negligible in the view of transverse space charge effect. Therefore, the electron beam is stable up to 10 A order in PNC linac design. Of course, the problem for RF supply is out of consideration here. It is important to estimate other longitudinal effect such as beam bunch effect which is lasting unevaluated. (author)

  7. Ion beams in materials processing and analysis

    CERN Document Server

    Schmidt, Bernd

    2012-01-01

    This book covers ion beam application in modern materials research, offering the basics of ion beam physics and technology and a detailed account of the physics of ion-solid interactions for ion implantation, ion beam synthesis, sputtering and nano-patterning.

  8. Fractal characterization of the silicon surfaces produced by ion beam irradiation of varying fluences

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, R.P. [Department of Physics, University of Allahabad, Allahabad, UP 211002 (India); Kumar, T. [Department of Physics, Central University of Haryana, Jant-Pali, Mahendergarh, Haryana 123029 (India); Mittal, A.K. [Department of Physics, University of Allahabad, Allahabad, UP 211002 (India); K Banerjee Centre of Atmospheric and Ocean Studies, University of Allahabad, Allahabad, UP 211002 (India); Dwivedi, S., E-mail: suneetdwivedi@gmail.com [K Banerjee Centre of Atmospheric and Ocean Studies, University of Allahabad, Allahabad, UP 211002 (India); Kanjilal, D. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, PO Box 10502, New Delhi 110 067 (India)

    2015-08-30

    Highlights: • Fractal analysis of Si(1 0 0) surface morphology at varying ion fluences. • Autocorrelation function and height–height correlation function as fractal measures. • Surface roughness and lateral correlation length increases with ion fluence. • Ripple pattern of the surfaces is found at higher ion fluences. • Wavelength of the ripple surfaces is computed for each fluence. - Abstract: Si (1 0 0) is bombarded with 200 keV Ar{sup +} ion beam at oblique incidence with fluences ranging from 3 × 10{sup 17} ions/cm{sup 2} to 3 × 10{sup 18} ions/cm{sup 2}. The surface morphology of the irradiated surfaces is captured by the atomic force microscopy (AFM) for each ion fluence. The fractal analysis is performed on the AFM images. The autocorrelation function and height–height correlation function are used as fractal measures. It is found that the average roughness, interface width, lateral correlation length as well as roughness exponent increase with ions fluence. The analysis reveals the ripple pattern of the surfaces at higher fluences. The wavelength of the ripple surfaces is computed for each ion fluence.

  9. E-beam-patterned hydrogels to control nanoscale surface bioactivity

    Science.gov (United States)

    Krsko, P.; Saaem, I.; Clancy, R.; Geller, H.; Soteropoulos, P.; Libera, M.

    2005-11-01

    We are interested in controlling the spatial distribution of proteins on surfaces at cellular and subcellular length scales. To do this, we use a variation of e-beam lithography in a field-emission scanning electron microscope (SEM) to radiation crosslink thin films of water- soluble polymers such as poly(ethylene glycol) [PEG] and poly (carboxylic acids). We can simultaneously pattern the resulting hydrogels on silicon or glass surfaces with nanoscale and microscale feature sizes. Using hydroxy-terminated PEG 6800 we create gels with swell ratios between unity and fifteen depending on the degree of radiation crosslinking, and the swelling properties can be interpreted in terms of the Flory-Rehner formulation modified for one-dimensional swelling. While lightly-crosslinked PEG gels resist protein adsorption and cell adhesion as expected, highly crosslinked PEG gels adsorb such proteins as fibronectin and laminin and consequently become adhesive to fibroblasts, macrophages, and neurons. By spatially modulating the degree of crosslinking, we can localize these cells on surfaces and, for example, direct neurite outgrowth. If instead of using hydroxy-terminated PEG we use amine- terminated PEG, we introduce the additional flexibility of creating high-swelling PEG gels that resist nonspecific protein adsorption but to which specific proteins can be covalently bound. These can be surface patterned at submicron spacings, and we can pattern 7500 nanohydrogels in a 100 micron diameter arrays in 10 seconds. This is an areal density ~104 times greater than a modern DNA/protein chip, and the required bioreagents for chip fabrication and processing are proportionately less. We can bind fibronectin and laminin to different arrays, and we show that these proteins maintain their biospecificity after binding to the nanohydrogels with high fidelity. Looking to applications in next-generation protein-chip technology, our most recent experiments compare the performance of nanohydrogel

  10. Analysis of CuInSe2: Electron and ion beam effects

    Science.gov (United States)

    Kazmerski, L. L.; Burnham, N. A.; Swartzlander, A. B.; Nelson, A. J.; Asher, S. E.

    The effects of electron and ion beams used in the analysis of CuInSe2 surfaces are examined. Potential changes in the surface chemistry-including oxidation, desorption and preferential species removal-under a range of incident probe conditions are investigated for possible artifactural information generation. Emphasis is placed on the relationships between beam conditions and oxygen chemisorption and physisorption, since oxygen treatments of devices utilizing this semiconductor are critial to performance. Single crystals and polycrystalline thin films are analyzed and compared to establish the beam-induced phenomena.

  11. Electron beam effects in the analysis of compound semiconductors and devices

    Energy Technology Data Exchange (ETDEWEB)

    Kazmerski, L.L.; Burnham, N.A.; Swartzlander, A.B.; Nelson, A.J.; Asher, S.E.

    1987-09-01

    The effects of electron beams on the analysis of CuInSe/sub 2/ surfaces are examined in this paper. Potential changes in the surface chemistry: including oxidation and desorption: under a range of incident probe conditions, are investigated for possible artifactual information generation. Emphasis is placed on the relationships between beam conditions and oxygen chemisorption and physisorption, since oxygen treatments of devices utilizing this semiconductor are critical to performance. Single crystals and polycrystalline thin films are analyzed and compared to establish the beam-induced phenomena.

  12. A piecewise continuous Timoshenko beam model for the dynamic analysis of tapered beam-like structures

    Science.gov (United States)

    Shen, Ji Yao; Abu-Saba, Elias G.; Mcginley, William M.; Sharpe, Lonnie, Jr.; Taylor, Lawrence W., Jr.

    1992-01-01

    Distributed parameter modeling offers a viable alternative to the finite element approach for modeling large flexible space structures. The introduction of the transfer matrix method into the continuum modeling process provides a very useful tool to facilitate the distributed parameter model applied to some more complex configurations. A uniform Timoshenko beam model for the estimation of the dynamic properties of beam-like structures has given comparable results. But many aeronautical and aerospace structures are comprised of non-uniform sections or sectional properties, such as aircraft wings and satellite antennas. This paper proposes a piecewise continuous Timoshenko beam model which is used for the dynamic analysis of tapered beam-like structures. A tapered beam is divided into several segments of uniform beam elements. Instead of arbitrarily assumed shape functions used in finite element analysis, the closed-form solution of the Timoshenko beam equation is used. Application of the transfer matrix method relates all the elements as a whole. By corresponding boundary conditions and compatible conditions a characteristic equation for the global tapered beam has been developed, from which natural frequencies can be derived. A computer simulation is shown in this paper, and compared with the results obtained from the finite element analysis. While piecewise continuous Timoshenko beam model decreases the number of elements significantly; comparable results to the finite element method are obtained.

  13. Nonlinear dynamic characteristic analysis of jointed beam with clearance

    Science.gov (United States)

    Zhang, Jing; Guo, Hong-Wei; Liu, Rong-Qiang; Wu, Juan; Kou, Zi-Ming; Deng, Zong-Quan

    2016-12-01

    The impact and elasticity of discontinuous beams with clearance frequently affect the dynamic response of structures used in space missions. This study investigates the dynamic response of jointed beams which are the periodic units of deployable structures. The vibration process of jointed beams includes free-play and impact stages. A method for the dynamic analysis of jointed beams with clearance is proposed based on mode superposition and instantaneous static deformation. Transfer matrix, which expresses the relationship of the responses before and after the impact of jointed beams, is derived to calculate the response of the jointed beams after a critical position. The dynamic responses of jointed beams are then simulated. The effects of various parameters on the displacement and velocity of beams are investigated.

  14. Studies of surface plasmon resonance sensor using bi-beam differential measurement approach

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, a low-cost measurement approach with bi-beam was presented, which can be used for real-time detection and online analysis of solution refractive index, based on systematical analysis and experiments of conventional detection methods on surface plasmon resonance sensor. This novel method was analyzed theoretically and based on it a sensor system set was established. The factors that affect the sensor's sensitivity and working range were discussed. The angular adjustment setup was simplified, errors produced by movable components were avoided and the maneuverability was enhanced with this new method.The noiseproof feature and stability of the sensor system were greatly improved as well.

  15. PIXE and ion beam analysis in forensics

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Melanie; Warmenhoven, John [Deparlmenl of Chemislry, Universily of Surrey (United Kingdom); Chrislopher, Matt; Kirkby, Karen; Palitsin, Vladimir; Grime, Geoff; Jeynes, Chris; Jones, Brian; Wenn, Roger [Surrey lon Beam Cenlre, Universily of Surrey (United Kingdom)

    2013-07-01

    Full text: University of Surrey has, for the past four years, collaborated with police institutions from across Europe and the rest of the world lo scope potential applications of ion beam analysis (IBA) in forensic science. In doing this we have consulted practitioners across a range of forensic disciplines, and critically compared IBA with conventional characterisation techniques to investigate the areas in which IBA can add evidential value. In this talk, the results of this feasibility study will be presented, showing the types of sample for which IBA shows considerable promise. We will show how a combination of PIXE with other IBA techniques (EBS, PIGE, MeV-SIMS) can be used to give unprecedented characterisation of forensic samples and comment on the significance of these results for forensic casework. We will also show cases where IBA not appear to add any significant improvement over conventional techniques. (author)

  16. Vlasov analysis of microbunching instability for magnetized beams

    Directory of Open Access Journals (Sweden)

    C.-Y. Tsai

    2017-05-01

    Full Text Available For a high-brightness electron beam with high bunch charge traversing a recirculation beam line, coherent synchrotron radiation and space charge effects may result in microbunching instability (MBI. Both tracking simulation and Vlasov analysis for an early design of a circulator cooler ring (CCR for the Jefferson Lab Electron Ion Collider (JLEIC reveal significant MBI [Ya. Derbenev and Y. Zhang, Proceedings of the Workshop on Beam Cooling and Related Topics, COOL’09, Lanzhou, China, 2009 (2009, FRM2MCCO01]. It is envisioned that the MBI could be substantially suppressed by using a magnetized beam. In this paper we have generalized the existing Vlasov analysis, originally developed for a nonmagnetized beam (or transversely uncoupled beam, to the description of transport of a magnetized beam including relevant collective effects. The new formulation is then employed to confirm prediction of microbunching suppression for a magnetized beam transport in the recirculation arc of a recent JLEIC energy recovery linac (ERL based cooler design for electron cooling. It is found that the smearing effect in the longitudinal beam phase space originates from the large transverse beam size as a nature of the magnetized beams and becomes effective through the x-z correlation when the correlated distance is larger than the microbunched scale. As a comparison, MBI analysis of the early design of JLEIC CCR is also presented in this paper.

  17. Measurement and analysis of the effect of an uneven surface (STEP) in an electron beam quality control planners; Medida y analisis de efecto de una superficie irregular (ESCALON) en un haz de electrones para control de calidad de planificadores

    Energy Technology Data Exchange (ETDEWEB)

    Angulo Pain, E.; Urena Llinares, A.; Ramos Caballero, L. J.; Quinones Rodriguez, L. A.; Castro Ramirez, I.; Iborro Oquendo, M.

    2011-07-01

    The objective of this study is to analyze the behavior of the algorithm for calculating electron of our scheduler when there is a discontinuity or step in the phantom with respect to the incidence of the beam. It reflects the special situation in some areas of treatment where the irregularity on the surface is very large surface constituting a real step, as for example in areas close to the jaw. Therefore, as stated in the National Protocol for quality control planning systems of radiation therapy in SEFM DOH5 test, we verify the accuracy of the calculation under the conditions described above.

  18. Micro-beam and pulsed laser beam techniques for the micro-fabrication of diamond surface and bulk structures

    Energy Technology Data Exchange (ETDEWEB)

    Sciortino, S. [Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Bellini, M. [European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); Istituto Nazionale di Ottica (INO-CNR), Largo Enrico Fermi 6, 50125 Firenze (Italy); Bosia, F. [Physics Department and “Nanostructured Interfaces and Surfaces” Inter-departmental Centre, University of Torino, via P. Giuria 1, 10125 Torino (Italy); INFN Sezione di Torino, via P. Giuria 1, 10125 Torino (Italy); Calusi, S. [Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Corsi, C. [Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); Czelusniak, C. [Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Gelli, N. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); and others

    2015-04-01

    Micro-fabrication in diamond is applicable in a wide set of emerging technologies, exploiting the exceptional characteristics of diamond for application in bio-physics, photonics and radiation detection. Micro ion-beam irradiation and pulsed laser irradiation are complementary techniques, which permit the implementation of complex geometries, by modification and functionalization of surface and/or bulk material, modifying the optical, electrical and mechanical characteristics of the material. In this article we summarize the work done in Florence (Italy), concerning ion beam and pulsed laser beam micro-fabrication in diamond.

  19. Tailoring surface properties of polymeric blend material by ion beam bombardment

    Science.gov (United States)

    Ali, Z. I.; Abdul-Kader, A. M.; Rizk, R. A. M.; Ali, M.

    2013-10-01

    In this work, LDPE/SBR polymer blend samples were bombarded with 130 keV He and 320 keV Ar ions at different fluencies ranging from 1×1013 to 2×1016 ions cm-2. The changes in surface properties of the ion-bombarded polymers were investigated with ultraviolet-visible (UV-vis) spectroscopy, Photoluminescence (PL) and energy dispersive X-ray (EDX) techniques. The variations in the wettability, surface free energy and spreading coefficient of ion beam bombarded LDPE polymer blend samples have been studied. The UV-vis analysis revealed that the transmission spectra shifted towards lower energy region after bombardment with increasing ion fluence. This shift clearly reflects decrease in optical band gap. A remarkable decrease in the PL intensity with increasing ion beam fluence was observed. The EDX study indicates the oxygen uptake increases with increasing ion fluence. Contact angle measurements showed that wettability, surface free energy and spreading coefficient of LDPE blends samples have increased with increasing ion fluence. This increase in the wettability and surface free energy of the bombarded samples are attributed to formation of oxidized layer on the polymer surface, which apparently occurs after exposure of bombarded samples to the air.

  20. Static Analysis of Functionally Graded Composite Beams

    Science.gov (United States)

    Das, S.; Sarangi, S. K.

    2016-09-01

    This paper presents a study of functionally graded (FG) composite beam. The FG material for the beam is considered to be composed of different layers of homogeneous material. The fiber volume fraction corresponding to each layer is calculated by considering its variation along the thickness direction (z) according to a power law. Accordingly, the effective properties of the homogeneous layers are estimated and a beam composed of this FG material is modelled using the commercially available ANSYS software. The solid 186 layered structural solid element has been used for discretization of the model of the FG beam. The model developed is validated by comparing the results with those numerical results available in literature. Results are presented for simply supported and fixed boundary conditions for the FG beam. The stress distribution across the thickness of the FG composite beam has also been analyzed.

  1. Applications of the BEam Cross section Analysis Software (BECAS)

    DEFF Research Database (Denmark)

    Blasques, José Pedro Albergaria Amaral; Bitsche, Robert; Fedorov, Vladimir;

    2013-01-01

    A newly developed framework is presented for structural design and analysis of long slender beam-like structures, e.g., wind turbine blades. The framework is based on the BEam Cross section Analysis Software – BECAS – a finite element based cross section analysis tool. BECAS is used for the gener......A newly developed framework is presented for structural design and analysis of long slender beam-like structures, e.g., wind turbine blades. The framework is based on the BEam Cross section Analysis Software – BECAS – a finite element based cross section analysis tool. BECAS is used...... for the generation of beam finite element models which correctly account for effects stemming from material anisotropy and inhomogeneity in cross sections of arbitrary geometry. These type of modelling approach allows for an accurate yet computationally inexpensive representation of a general class of three...

  2. The Stress Analysis and Tests on the Hinge Beam of the Diamond Synthesis Cubic Press

    Directory of Open Access Journals (Sweden)

    Ma Liang

    2016-01-01

    Full Text Available To deal with the problem of the lug fractures of hinge beam caused by the fatigue and overload during the operation of the cubic press, the analysis methods of finite element are applied to the analysis of the internal stress distributions of the hinge beam. The simulation results show that the internal stress of the hinge beam mainly concentrates on the upper surface of the lug roots connecting the outer cylinder with the both lugs. According to the data of simulation and analysis as well as the actual fracture situations, considering the strain-test methods we have designed the schemes of testing the strain on the lugs of hinge beam. And the strain measurements of the lugs are completed by the repeated loading experiments. Comparing the data of simulation and analysis with the measured data has verified their consistency. It also confirms the model established by the simulation and analysis is reasonable and accurate at the same time.

  3. High energy ion beam analysis at ARRONAX

    Energy Technology Data Exchange (ETDEWEB)

    Koumeir, C.; Haddad, F.; Michel, N. [Subatech, Nantes (France); GIP ARRONAX, Saint-Herblain (France); Guertin, A.; Metivier, V.; Michel, N.; Ragreb, D.; Servagent, N. [Subatech, Nantes (France)

    2013-07-01

    Full text: ARRONAX, acronym for 'Accelerator for Research in Radiochemistry and Oncology at Nantes' is a high energy cyclotron. It is characterized by the acceleration of several types of particle beams: 68 MeV alpha, 15-35 MeV deuterons and 30-68 MeV protons. A platform was implemented on ARRONAX to perform non-destructive materials analysis with X and gamma rays emission (PIXE-PIGE). A proper selection of the projectile type and beam energy allows to analyze heavy and light elements in thin and thick samples. Our research activities are oriented along three axes: 1) Measurements of K X-ray production cross section for various elements to complement the databases at high energy. A first experiment has been conducted to measure these cross sections for copper and gold with protons energy between 34 and 68 MeV. 2) Study of the detection sensitivity which depends on the nuclear background and the Bremsstrahlung radiations. A dedicated shielding has been developed and detection limits below tens of μg/g/μC have been assessed using different referenced samples from IAEA. 3) Determination of concentration profile as function of the depth in a thick target. Using layered samples, we have showed for a target consisting of three different layers, the possibility to determine the sequence and thickness of each layer by using X and gamma rays measured respectively during and after irradiation. During this talk, I will present the characteristics and the capabilities of our platform. In the near future we intend to install the PIGE technique and use it with 15 MeV deuterons to analyze lightweight elements. (author)

  4. Data analysis of photon beam position at PLS-II

    Energy Technology Data Exchange (ETDEWEB)

    Ko, J.; Shin, S., E-mail: tlssh@postech.ac.kr; Huang, Jung-Yun; Kim, D.; Kim, C.; Kim, Ilyou; Lee, T.-Y.; Park, C.-D.; Kim, K. R. [Pohang Accelerator Laboratory, Pohang, Kyungbuk 790-834 (Korea, Republic of); Cho, Moohyun [Department of Physics, POSTECH, Pohang, Kyungbuk 790-834 (Korea, Republic of)

    2016-07-27

    In the third generation light source, photon beam position stability is critical issue on user experiment. Generally photon beam position monitors have been developed for the detection of the real photon beam position and the position is controlled by feedback system in order to keep the reference photon beam position. In the PLS-II, photon beam position stability for front end of particular beam line, in which photon beam position monitor is installed, has been obtained less than rms 1μm for user service period. Nevertheless, detail analysis for photon beam position data in order to demonstrate the performance of photon beam position monitor is necessary, since it can be suffers from various unknown noises. (for instance, a back ground contamination due to upstream or downstream dipole radiation, undulator gap dependence, etc.) In this paper, we will describe the start to end study for photon beam position stability and the Singular Value Decomposition (SVD) analysis to demonstrate the reliability on photon beam position data.

  5. ANALYSIS OF BEAMS WITH PIEZOELECTRIC ACTUATORS

    Institute of Scientific and Technical Information of China (English)

    林启荣; 刘正兴; 王宗利

    2001-01-01

    Based on the two-dimensional constitutive relationships of the piezoelectric material, an analytical solution for an intelligent beam excited by a pair of piezoelectric actuators is derived. With the solution the force and moment generated by two piezoelectric actuators and a pair of piezoelectric actuator/sensor are obtained. Examples of a cantilever piezoelectric laminated beam or a simply supported piezoelectric laminated beam, applied with voltages, are given.

  6. A microstructure- and surface energy-dependent third-order shear deformation beam model

    Science.gov (United States)

    Gao, X.-L.; Zhang, G. Y.

    2015-08-01

    A new non-classical third-order shear deformation model is developed for Reddy-Levinson beams using a variational formulation based on Hamilton's principle. A modified couple stress theory and a surface elasticity theory are employed. The equations of motion and complete boundary conditions for the beam are obtained simultaneously. The new model contains a material length scale parameter to account for the microstructure effect and three surface elastic constants to describe the surface energy effect. Also, Poisson's effect is incorporated in the new beam model. The current non-classical model recovers the classical elasticity-based third-order shear deformation beam model as a special case when the microstructure, surface energy and Poisson's effects are all suppressed. In addition, the newly developed beam model includes the models considering the microstructure dependence or the surface energy effect alone as limiting cases and reduces to two existing models for Bernoulli-Euler and Timoshenko beams incorporating the microstructure and surface energy effects. To illustrate the new model, the static bending and free vibration problems of a simply supported beam loaded by a concentrated force are analytically solved by directly applying the general formulas derived. For the static bending problem, the numerical results reveal that both the deflection and rotation of the simply supported beam predicted by the current model are smaller than those predicted by the classical model. Also, it is observed that the differences in the deflection and rotation predicted by the two beam models are very large when the beam thickness is sufficiently small, but they are diminishing with the increase in the beam thickness. For the free vibration problem, it is found that the natural frequency predicted by the new model is higher than that predicted by the classical beam model, and the difference is significant for very thin beams. These predicted trends of the size effect at the

  7. Surface modification of the patterned Al6061/SUS304 metal plates using the large electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Min; Kim, Jisu; Park, Sung Soo [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan Metropolitan City 689-798 (Korea, Republic of); Park, Hyung Wook, E-mail: hwpark@unist.ac.kr [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan Metropolitan City 689-798 (Korea, Republic of); Ki, Hyungson [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan Metropolitan City 689-798 (Korea, Republic of)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer We performed the large-electron-beam polishing of the patterned metal plates. Black-Right-Pointing-Pointer We observed its effect on surface hardness, surface roughness, and water repellency. Black-Right-Pointing-Pointer The contact angle for Al6061 and SUS304 increased after the electron-beam irradiation. Black-Right-Pointing-Pointer We observed the microstructure after the electron beam irradiation. - Abstract: Polishing is a finishing process used to improve surface integrity by reducing surface roughness and residual stress caused by other machining processes. The recently developed electron beam polishing method was used in this study to improve surface quality. In this process, an electron beam with a maximum diameter of 60 mm was applied for a few microseconds to melt and evaporate a metal surface. Al6061 and SUS304 metal plates were prepared with different geometric patterns and subjected to electron beam polishing. The surface roughness of the patterned SUS304 metal plate was significantly improved. However, the surface roughness of the patterned Al6061 metal plate became worse. Although the surface hardness decreased by approximately 10% on the re-solidified layers on both types of plates, the contact angle increased due to changes in surface morphology. The microstructure variation after the electron beam irradiation was also examined and compared with the thickness prediction of the re-solidified layer for Al6061 and SUS304 metal plates.

  8. Cell adhesion behavior on the silicone rubber surface modified by using ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, In Tae; Jung, Chan Hee; Nh, Young Chang; Choi, Jae Hak [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kuk, In Seol [Hanyang University, Seoul (Korea, Republic of); An, Mi Young [Chungnam National University, Daejeon (Korea, Republic of)

    2009-12-15

    In this study we studied cell adhesion and proliferation on the surface of a silicone rubber modified by ion beam irradiation. The surface property of the irradiated silicone rubber was characterized by water contact angle and FT-IR analyses. It was observed that human (HEK293) fibroblast cells exhibit strong adhesion to the irradiated silicone surface. This enhanced adhesion of mammalian cells can be attributed to the increase in the hydrophilicity of the silicone surface by ion beam irradiation.

  9. Human skin image analysis using coherent focused beam scattering

    Science.gov (United States)

    Zimnyakov, Dmitry A.; Tuchin, Valery V.; Utz, Sergei R.; Mishin, Alexey A.

    1995-02-01

    The analysis of statistical and correlation properties of speckle patterns formed during different skin tissue scanning by the sharply focused probing laser beam has been carried out. The influences of the biotissues' structural features on the speckle patterns formation under Gaussian beam illumination have been investigated. The relationships between the structural characteristics of the sample under study, Rayleigh range of the probing beam and normalized statistical moments of the speckle intensity (contrast and asymmetry coefficient) are discussed for the different scatterer models. A phenomenological model of speckle pattern formation for the large-scale scatterers allows us to explain the dependence of speckle contrast and the coefficient of asymmetry on the generalized structure parameters and illumination conditions for the samples under study. The experimental investigations of the human skin structure features have been carried out using two types of the tissue samples by means of coherent scanning microscopy (CSM). Firstly, D-SQUAME discs (CuDerm Corporation, Texas, USA) have been used for the evaluation of skin dryness level. Secondly, the samples under study were the thin layers of normal and psoriatic epidermis (skin strippings). The dependencies of contrast and coefficient of asymmetry on the beam defocusing parameter and 2D correlation functions of speckle pattern intensity have been analyzed for different zones on the biotissue's surface. Particularly, promising results in skin dryness studies (using D-SQUAME discs) have been obtained. Our results and conventional 5-pattern kit scale are in good agreement. So, the presented method is accurate and objective and may be useful in novel cosmetic research and development.

  10. Thermal effects generated by high-intensity focused ultrasound beams at normal incidence to a bone surface.

    Science.gov (United States)

    Nell, Diane M; Myers, Matthew R

    2010-01-01

    Experiments and computations were performed to study factors affecting thermal safety when high-intensity focused ultrasound (HIFU) beams are normally incident (i.e., beam axis normal to the interface) upon a bone/soft-tissue interface. In particular, the temperature rise and thermal dose were determined as a function of separation between the beam focus and the interface. Under conditions representative of clinical HIFU procedures, it was found that the thermal dose at the bone surface can exceed the threshold for necrosis even when the beam focus is more than 4 cm from the bone. Experiments showed that reflection of the HIFU beam from the bone back into the transducer introduced temperature fluctuations of as much as +/-15% and may be an important consideration for safety analyses at sufficiently high acoustic power. The applicability of linear propagation models in predicting thermal dose near the interface was also addressed. Linear models, while underpredicting thermal dose at the focus, provided a conservative (slight overprediction) estimate of thermal dose at the bone surface. Finally, temperature rise due to absorption of shear waves generated by the HIFU beam in the bone was computed. Modeling shear-wave propagation in the thermal analysis showed that the predicted temperature rise off axis was as much as 30% higher when absorption of shear waves is included, indicating that enhanced heating due to shear-wave absorption is potentially important, even for normally incident HIFU beams.

  11. The effect of E-beam engineered surface structures on attachment, proliferation and differentiation of human mesenchymal stem cells.

    Science.gov (United States)

    Biemond, J Elizabeth; Hannink, G; Verdonschot, N; Buma, P

    2011-01-01

    Electron beam melting (E-beam) is a new technology to produce 3-dimensional surface topographies for cementless orthopedic implants. The effect of two newly designed highly porous E-beam engineered surface structures (cubic and star) on attachment, proliferation and differentiation of human mesenchymal stem cells (hMSCs) was investigated and compared to a solid sandblasted control. SEM analysis showed that the E-beam structures allowed cells to attach and spread. Proliferation on the new surface structures was comparable to the solid control. Furthermore, differentiation on the 3D structures was comparable to the control specimen. When culturing 300,000 cells for 10 days, the cubic structure showed a significantly higher differentiation rate compared to the sandblasted specimen. We conclude that the results for attachment, proliferation and differentiation of mesenchymal stem cells on the newly engineered 3-dimensional E-beam surface topographies are promising. In vivo experiments are necessary to assess the bone ingrowth potential of the new surface structures.

  12. Parametric Design and Mechanical Analysis of Beams based on SINOVATION

    Science.gov (United States)

    Xu, Z. G.; Shen, W. D.; Yang, D. Y.; Liu, W. M.

    2017-07-01

    In engineering practice, engineer needs to carry out complicated calculation when the loads on the beam are complex. The processes of analysis and calculation take a lot of time and the results are unreliable. So VS2005 and ADK are used to develop a software for beams design based on the 3D CAD software SINOVATION with C ++ programming language. The software can realize the mechanical analysis and parameterized design of various types of beams and output the report of design in HTML format. Efficiency and reliability of design of beams are improved.

  13. Sensitivity enhancement of surface thermal lens technique with a short-wavelength probe beam: Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaorong [Institute of Optics and Electronics, Chinese Academy of Sciences and Key Laboratory of Optical Engineering, Chinese Academy of Sciences, Chengdu 610209 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Bincheng [Institute of Optics and Electronics, Chinese Academy of Sciences and Key Laboratory of Optical Engineering, Chinese Academy of Sciences, Chengdu 610209 (China)

    2015-02-15

    Surface thermal lens is a highly sensitive photothermal technique to measure low absorption losses of various solid materials. In such applications, the sensitivity of surface thermal lens is a key parameter for measuring extremely low absorption. In this paper, we experimentally investigated the influence of probe beam wavelength on the sensitivity of surface thermal lens for measuring the low absorptance of optical laser components. Three probe lasers with wavelength 375 nm, 633 nm, and 1570 nm were used, respectively, to detect the surface thermal lens amplitude of a highly reflective coating sample excited by a cw modulated Gaussian beam at 1064 nm. The experimental results showed that the maximum amplitude of surface thermal lens signal obtained at corresponding optimized detection distance was inversely proportional to the wavelength of the probe beam, as predicted by previous theoretical model. The sensitivity of surface thermal lens could, therefore, be improved by detecting surface thermal lens signal with a short-wavelength probe beam.

  14. Diffraction analysis of beams for barcode scanning

    Science.gov (United States)

    Eastman, Jay M.; Quinn, Anna M.

    1991-02-01

    Laser based bar code scanners utilize large f/# beams to attain a large depth of focus. The intensity cross-section of the laser beam is generally not uniform but is frequently approximated by a Gaussian intensity profile. In the case of laser diodes the beam cross-section is a two dimensional distribution. It is well known that the focusing properties of large f/# Gaussian beams differ from the predictions of ray tracing techniques. Consequently analytic modeling of laser based bar code scanning systems requires techniques based on diffraction rather than on ray tracing in order to obtain agreement between theory and practice. The line spread function of the focused laser beam is generally the parameter of interest due to the one-dimensional nature of the bar code symbol. Some bar code scanners utilize an anamorphic optical system to produce a beam that that maintains an elliptical cross-section over an extended depth of focus. This elliptical beam shape is used to average over voids and other printing defects that occur in real world symbols. Since the scanner must operate over the maximum possible depth of field the beam emergent from the scanner must be analyzed in both its near field and far field regions in order to properly model the performance of the scanner.

  15. Electron beam deposition for nanofabrication : Insights from surface science

    NARCIS (Netherlands)

    Wnuk, J. D.; Rosenberg, S. G.; Gorham, J. M.; van Dorp, W. F.; Hagen, C. W.; Fairbrother, D. H.

    2011-01-01

    Electron beam induced deposition (EBID) is a direct-write lithographic technique that utilizes the dissociation of volatile precursors by a focused electron beam in a low vacuum environment to create nanostructures. Notable advantages of EBID over competing lithographic techniques are that it is a s

  16. Surface and thermal effects on vibration of embedded alumina nanobeams based on novel Timoshenko beam model

    Institute of Scientific and Technical Information of China (English)

    B AMIRIAN; R HOSSEINI-ARA; H MOOSAVI

    2014-01-01

    This paper deals with the free vibration analysis of circular alumina (Al2O3) nanobeams in the presence of surface and thermal effects resting on a Pasternak foun-dation. The system of motion equations is derived using Hamilton’s principle under the assumptions of the classical Timoshenko beam theory. The effects of the transverse shear deformation and rotary inertia are also considered within the framework of the mentioned theory. The separation of variables approach is employed to discretize the governing equa-tions which are then solved by an analytical method to obtain the natural frequencies of the alumina nanobeams. The results show that the surface effects lead to an increase in the natural frequency of nanobeams as compared with the classical Timoshenko beam model. In addition, for nanobeams with large diameters, the surface effects may increase the natural frequencies by increasing the thermal effects. Moreover, with regard to the Pasternak elastic foundation, the natural frequencies are increased slightly. The results of the present model are compared with the literature, showing that the present model can capture correctly the surface effects in thermal vibration of nanobeams.

  17. Operational Modal Analysis on laminated glass beams

    OpenAIRE

    López Aenlle, Manuel; Fernández, Pelayo; Villa García, Luis Manuel; Barredo Egusquiza, Josu; Hermanns, Lutz Karl Heinz; Fraile de Lerma, Alberto

    2011-01-01

    Laminated glass is a sandwich element consisting of two or more glass sheets, with one or more interlayers of polyvinyl butyral (PVB). The dynamic response of laminated glass beams and plates can be predicted using analytical or numerical models in which the glass and the PVB are usually modelled as linear-elastic and linear viscoelastic materials, respectively. In this work the dynamic behavior of laminated glass beams are predicted using a finite element model and the analytical model ...

  18. Bending analysis of a functionally graded piezoelectric cantilever beam

    Institute of Scientific and Technical Information of China (English)

    YU Tao; ZHONG Zheng

    2007-01-01

    A new analysis based on Airy stress function method is presented for a functionally graded piezoelectric material cantilever beam.Assuming that the mechanical and electric properties of the material have the same variations along the thickness direction,a two-dimensional plane elasticity solution is obtained for the coupling electroelastic fields of the beam under different loadings.This solution will be useful in analyzing FGPM beam with arbitrary variations of material properties.The influences of the functionally graded material properties on the structural response of the beam subjected to different loads are also studied through numerical examples.

  19. Bending analysis of a functionally graded piezoelectric cantilever beam

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new analysis based on Airy stress function method is presented for a functionally graded piezoelectric material cantilever beam. Assuming that the mechanical and electric properties of the material have the same variations along the thickness direction, a two-dimensional plane elasticity solution is obtained for the coupling electroelastic fields of the beam under different loadings. This solution will be useful in analyzing FGPM beam with arbitrary variations of material properties. The influences of the functionally graded material properties on the structural response of the beam subjected to different loads are also studied through numerical examples.

  20. Analysis of lateral stability of I-section aluminum beams

    Institute of Scientific and Technical Information of China (English)

    CHENG Ming; SHI Yongjiu; WANG Yuanqing

    2006-01-01

    This paper focuses on the lateral buckling of laterally-unrestrained aluminum beams subjected to a concentrated, uniformly loading and pure-bending action. The design methods of lateral stability of aluminum beams in the current codes are discussed. The influence of material property on the lateral buckling of aluminum beams is investigated with finite element analysis (FEA) methods. Some numerical examples are given, and the results from current codes are compared with the FEA solutions. The design method on lateral stability of steel beams specified in the Chinese standard GB 50017-2003 is modified to calibrate the stability factors of aluminum beams according to the European code, British code, and American code, and the modified method is verified by FEA results. Through comparison with the available test results, the modified design method for overall stability of aluminum bending members is proposed in this paper and proved applicable in the design of lateral stability of aluminum beams.

  1. Real-time detection of focal position of workpiece surface during laser processing using diffractive beam samplers

    Science.gov (United States)

    Cao, Binh Xuan; Hoang, PhuongLe; Ahn, Sanghoon; Kim, Jeng-o.; Sohn, Hyonkee; Noh, Jiwhan

    2016-11-01

    The real-time fabrication of microgrooves on a curved surface using a laser beam, without preprogramming their shapes into the machining instructions, is a major challenge in laser processing owing to limitations associated with the real-time detection of the focal position. A new approach using a sampled fraction of the beam from a diffractive beam sampler (DBS) is therefore presented in order to overcome this limitation. By considering the sampled fraction of the beam an analysis of the results allows for precise positioning of the specimen for focal-point identification. This allows for the determination of the focus for a broad variety of laser types and laser powers, thereby providing stringent focusing conditions with high numerical apertures. This approach is easy to implement, inexpensive, independent of the roughness or granularity of the workpieces, and more importantly does not require auxiliary lasers and displacement sensors for real-time measurement during the fabrication process.

  2. Beam splitting at the output of photonic crystal waveguides with discrete surface point defects.

    Science.gov (United States)

    Wang, Qi; Zhang, Lanlan; Li, Qi

    2010-11-08

    With the method of adding two point defects on modulated surface, novel photonic crystal (PC) waveguide-based beam splitters were presented. The modulated surface layer supports surface states, and introduced discrete point defects can serve as discrete light emitters. The finite-difference time-domain (FDTD) simulations show that the number of beams is sensitive to the distance of two point defects. By adjusting the positions of the point defects, 1-to-N beam splitters can be realized. These simple, easy-to-fabricate and controllable structures have important potential applications in integrated optical circuits.

  3. Surface profiling of X-ray mirrors for shaping focused beams.

    Science.gov (United States)

    Laundy, David; Alianelli, Lucia; Sutter, John; Evans, Gwyndaf; Sawhney, Kawal

    2015-01-26

    Grazing incidence mirrors are a standard optic for focusing X-rays. Active mirrors, whose surface profile can be finely adjusted, allow control of beam shape and size at the sample. However, progress towards their routine use for beam shaping has been hampered by the strong striations in reflected beams away from the focal plane. Re-entrant (partly concave and partly convex) surface modifications are proposed for shaping X-ray beams to a top-hat in the focal plane while reducing the striations caused by unavoidable polishing errors. A method for constructing such surfaces with continuous height and slope (but only piecewise continuous curvature) will be provided. Ray tracing and wave propagation calculations confirm its effectiveness. A mirror system is proposed allowing vertical beam sizes in the range 0.5 to 10μm. A prototype will be fabricated and is expected to have applications on many synchrotron X-ray beamlines.

  4. Influence of ion beam bombardment on surface roughness of K9 glass substrate

    Science.gov (United States)

    Pan, Yongqiang; Huang, Guojun; Hang, Lingxia

    2010-10-01

    Ion beam bombardment optical substrate surface has become an important part of process of optical thin films deposition. In this work, the K9 optical glass is bombarded by the broad beam cold cathode ion source. The dependence of the K9 glass surface roughness on the ion beam bombardment time, the ion energy, the distance and incident angle are all investigated, respectively. Surface roughness of K9 glass is measured using Talysurf CCI. The experimental results show that when the ion energy is 800ev, the bombardment distance of 20cm, with the ion beam bombardment time increased, the K9 substrate surface roughness first increase and then decrease. When the ion beam bombardment distance is 20cm, bombardment time is 10min, with the bombardment energy increases, substrate surface roughness increase first and then decrease, especially in the ion energy greater than 1200ev, the optical substrate surface roughness rapidly increases. When the ion energy is 800 eV, bombardment time is 10min, with the bombardment distance increase, substrate surface roughness decrease gradually. Furthermore, the incident angle of ion beam plays an important role in improving the K9 glass surface roughness.

  5. Nonlinear analysis of concrete beams strengthened by date palm fibers

    Science.gov (United States)

    Bouzouaid, Samia; Kriker, Abdelouahed

    2017-02-01

    The behaviour of concrete beams strengthened with date palm fibers was studied by Nonlinear Finite Element Analysis using ANSYS software. Five beams that were experimentally tested in a previous research were considered. The results obtained from the ANSYS finite element analysis are compared with the experimental data for the five beams with different amounts of fibres, ranging from 0.2% to 0.5% by a step equal to 0.1% and with a fibre length of 0.04 m. The results obtained by FEA showed good agreement with those obtained by the experimental program. This research demonstrates the ability of FEA in predicting the behaviour of beams strengthened with Date Palm fibers. It will help researchers in studying beams with different configurations without the need to go through the lengthy experimental testing programs.

  6. Vlasov Analysis of Microbunching Gain for Magnetized Beams

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Cheng Ying [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Derbenev, Yaroslav [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Li, Rui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-10-01

    For a high-brightness electron beam with low energy and high bunch charge traversing a recirculation beamline, coherent synchrotron radiation and space charge effect may result in the microbunching instability (MBI). Both tracking simulation and Vlasov analysis for an early design of Circulator Cooler Ring for the Jefferson Lab Electron Ion Collider reveal significant MBI. It is envisioned these could be substantially suppressed by using a magnetized beam. In this work, we extend the existing Vlasov analysis, originally developed for a non-magnetized beam, to the description of transport of a magnetized beam including relevant collective effects. The new formulation will be further employed to confirm prediction of microbunching suppression for a magnetized beam transport in a recirculating machine design.

  7. LHC Beam Dump System: Analysis of beam commissioning, performance and the consequences of abnormal operation

    CERN Document Server

    Kramer, Thomas

    2011-01-01

    The LHC accelerates proton beams to a momentum of up to 7 TeV/c. At this energy level and with nominal beam intensity the stored energy of 360 MJ per beam is sufficient to melt 500 kg of copper. In addition up to 10 GJ are stored within the LHC magnet system at top energy. It is obvious that such a machine needs well designed safety and protection systems. The LHC Beam Dump System (LBDS) is such a system and one of the most critical once concerning machine protection and safe operation. It is used to dispose of high intensity beams between 450 GeV and 7 TeV and is thus designed to fast extract beam in a loss free way and to transfer it to an external absorber. For each ring systems of 15 horizontal fast kicker magnets (MKD), 15 vertically deflecting magnetic septa (MSD) and 10 diluter kicker magnets (MKB) are installed. This thesis is concerned with the analysis of the LBDS performance under normal operating parameters as well as under abnormal conditions like in the event of asynchronous beam abort or missin...

  8. Ion beam deposition and surface characterization of thin multi-component oxide films during growth.

    Energy Technology Data Exchange (ETDEWEB)

    Krauss, A.R.; Im, J.; Smentkowski, V.; Schultz, J.A.; Auciello, O.; Gruen, D.M.; Holocek, J.; Chang, R.P.H.

    1998-01-13

    Ion beam deposition of either elemental targets in a chemically active gas such as oxygen or nitrogen, or of the appropriate oxide or nitride target, usually with an additional amount of ambient oxygen or nitrogen present, is an effective means of depositing high quality oxide and nitride films. However, there are a number of phenomena which can occur, especially during the production of multicomponent films such as the ferroelectric perovskites or high temperature superconducting oxides, which make it desirable to monitor the composition and structure of the growing film in situ. These phenomena include thermodynamic (Gibbsian), and oxidation or nitridation-driven segregation, enhanced oxidation or nitridation through production of a highly reactive gas phase species such as atomic oxygen or ozone via interaction of the ion beam with the target, and changes in the film composition due to preferential sputtering of the substrate via primary ion backscattering and secondary sputtering of the film. Ion beam deposition provides a relatively low background pressure of the sputtering gas, but the ambient oxygen or nitrogen required to produce the desired phase, along with the gas burden produced by the ion source, result in a background pressure which is too high by several orders of magnitude to perform in situ surface analysis by conventional means. Similarly, diamond is normally grown in the presence of a hydrogen atmosphere to inhibit the formation of the graphitic phase.

  9. Crystalline inverted membranes grown on surfaces by electrospray ion beam deposition in vacuum.

    Science.gov (United States)

    Rauschenbach, Stephan; Rinke, Gordon; Malinowski, Nikola; Weitz, R Thomas; Dinnebier, Robert; Thontasen, Nicha; Deng, Zhitao; Lutz, Theresa; de Almeida Rollo, Pedro Martins; Costantini, Giovanni; Harnau, Ludger; Kern, Klaus

    2012-05-22

    Crystalline inverted membranes of the nonvolatile surfactant sodium dodecylsulfate are found on solid surfaces after electrospray ion beam deposition (ES-IBD) of large SDS clusters in vacuum. This demonstrates the equivalence of ES-IBD to conventional molecular beam epitaxy.

  10. Electron beam processed plasticized epoxy coatings for surface protection

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Mervat S. [National Center for Radiation Research and Technology, Nasr City (Egypt); Mohamed, Heba A., E-mail: hebaamohamed@gmail.com [National Research Center, Dokki (Egypt); Kandile, Nadia G. [University College for Girls, Ain Shams University (Egypt); Said, Hossam M.; Mohamed, Issa M. [National Center for Radiation Research and Technology, Nasr City (Egypt)

    2011-10-17

    Highlights: {center_dot} Coating formulations with EA 70%, HD 20%, and castor oil 10% under 1 Mrad pass{sup -1} irradiation dose showed the best adhesion and passed bending tests. {center_dot} The prepared EP-SF-An adduct improve anti-corrosion properties of coatings without any significant effect on physical, mechanical and chemical properties of the cured film. The optimum amount of aniline adduct as corrosion inhibitor was found to be 0.4 g for 100 g of coating formulation. {center_dot} The corrosion inhibition efficiency of the prepared adduct competed the commercial efficiency. - Abstract: Epoxy acrylate oligomer (EA) was plasticized by adding different plasticizers such as epoxidized soybean oil, glycerol and castor oil and cured by electron beam (EB). Different irradiation doses (1, 2.5 and 5 Mrad pass{sup -1}) were used in the curing process. The effect of both different irradiation doses and plasticizers on the end use performance properties of epoxy acrylate coating namely, pencil hardness, bending test, adhesion test, acid and alkali resistance test were studied. It was observed that incorporation of castor oil in epoxy acrylate diluted by 1,6-hexanediol diacrylate (HD) monomer with a ratio (EA 70%, HD 20%, castor oil 10%) under 1 Mrad pass{sup -1} irradiation dose improved the physical, chemical and mechanical properties of cured films than the other plasticizer. Sunflower free fatty acid was epoxidized in situ under well established conditions. The epoxidized sunflower free fatty acids (ESFA) were subjected to react with aniline in sealed ampoules under inert atmosphere at 140 deg. C. The produced adducts were added at different concentrations to epoxy acrylate coatings under certain EB irradiation dose and then evaluated as corrosion inhibitors for carbon steel surfaces in terms of weight loss measurements and corrosion resistance tests. It was found that, addition of 0.4 g of aniline adduct to 100 g epoxy acrylate formula may give the best corrosion

  11. In vivo evaluation of cp Ti implants with modified surfaces by laser beam with and without hydroxyapatite chemical deposition and without and with thermal treatment: topographic characterization and histomorphometric analysis in rabbits.

    Science.gov (United States)

    Queiroz, Thallita Pereira; de Molon, Rafael Scaf; Souza, Francisley Ávila; Margonar, Rogério; Thomazini, Anahi Herrera Aparecida; Guastaldi, Antônio Carlos; Hochuli-Vieira, Eduardo

    2017-03-01

    We aimed to assess the surfaces of commercially pure titanium implants (cp Ti) with modified surfaces by laser beam (LS) with and without hydroxyapatite (HA) deposition, without (HAB) and with (HABT) thermal treatment. Furthermore, we have compared them with implants with surfaces modified by acid treatment (AS) and with machined surfaces (MS) utilizing histomorphometric and descriptive histologic analyses. Surface topography characterization was analyzed by scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDX), and surface roughness (Ra) before implant installation. Forty-five rabbits received seventy-five implants in their left and right tibias and were randomly divided into five groups (n = 5 implants per group): (1) cp Ti implant modified by LS, (2) cp Ti implant modified by laser beam associated with HA deposition without heat treatment (HAB), (3) cp Ti implant modified by laser beam associated with HA deposition with heat treatment (HABT), (4) cp Ti implant with modified surface by means of acid treatment (Master Porous) commercially available (AS), and (5) cp Ti implant with MS commercially available. After 30, 60, and 90 days, the animals were euthanized and the implants and surrounding bone were removed and prepared by a non-decalcified histological process. The percentage of bone-to-implant contact (BIC) and the bone area fraction occupancy (BAFO) between the first three threads was evaluated to the higher cortical region. BIC (%) was statistically superior (p < 0.001) on the LS (69.36 ± 7.91, 71.67 ± 8.79, and 79.69 ± 3.3), HAB (73.22 ± 3.75, 69.48 ± 1.89, and 75.7 ± 4.62), and HABT (65.41 ± 5.51, 71.3 ± 2.5, and 79.68 ± 5.01) compared with AS (49.15 ± 5.76, 41.94 ± 2.85, and 57.18 ± 7.81) and MS (36.69 ± 7.24, 52.52 ± 2.75, and 51.31 ± 6.96) in the 30, 60, and 90-day periods, respectively. BAFO (%) of HAB at 30 days (90.17 ± 6.24) was statistically superior (p < 0.01) to

  12. Metallization of bacterial surface layer by cross-beam pulsed laser deposition

    Science.gov (United States)

    Pompe, Wolfgang; Mertig, Michael; Kirsch, Remo; Gorbunov, Andre A.; Sewing, Andreas; Engelhardt, Harald; Mensch, Axel

    1996-04-01

    We present first results on thin film metal deposition on the regular bacterial surface layer of Sporsarcina urea by pulsed laser deposition. To prevent structural damage of the biological specimen a recently developed cross beam technique is applied providing an effective filtering of the most energetic plasma particles. The deposited films are examined by low voltage scanning electron microscopy. The surface profile of the S-layer adsorbed onto mica substrate was investigated by atomic force microscopy. A lattice constant of 13.2 nm has been measured. The lattice parameters and the structural appearance of the protein layer is in reasonable agreement with the results of an electron microscopical 3D structural analysis.

  13. Large amplitude forced vibration analysis of cross-beam system ...

    African Journals Online (AJOL)

    user

    governing nonlinear differential equation of dynamic equilibrium for forced vibration of a ...... ω is the first natural frequency of the corresponding beam. ..... Although a separate free vibration analysis of the system is not carried out in course.

  14. Surface analysis the principal techniques

    CERN Document Server

    Vickerman, John C

    2009-01-01

    This completely updated and revised second edition of Surface Analysis: The Principal Techniques, deals with the characterisation and understanding of the outer layers of substrates, how they react, look and function which are all of interest to surface scientists. Within this comprehensive text, experts in each analysis area introduce the theory and practice of the principal techniques that have shown themselves to be effective in both basic research and in applied surface analysis. Examples of analysis are provided to facilitate the understanding of this topic and to show readers how they c

  15. Frictional and bone ingrowth properties of engineered surface topographies produced by electron beam technology.

    Science.gov (United States)

    Biemond, J Elizabeth; Aquarius, René; Verdonschot, Nico; Buma, Pieter

    2011-05-01

    Electron beam melting (E-beam) is a new technology to produce 3-dimensional surface topographies for cementless orthopedic implants. The friction coefficients of two newly developed E-beam produced surface topographies were in vitro compared with sandblasted E-beam and titanium plasma sprayed controls. Bone ingrowth (direct bone-implant contact) was determined by implanting the samples in the femoral condyles of 6 goats for a period of 6 weeks. Friction coefficients of the new structures were comparable to the titanium plasma sprayed control. The direct bone-implant contact was 23.9 and 24.5% for the new surface structures. Bone-implant contact of the sandblasted and titanium plasma sprayed control was 18.2 and 25.5%, respectively. The frictional and bone ingrowth properties of the E-beam produced surface structures are similar to the plasma-sprayed control. However, since the maximal bone ingrowth had not been reached for the E-beam structures during the relatively short-term period, longer-term follow-up studies are needed to assess whether the E-beam structures lead to a better long-term performance than surfaces currently in use, such as titanium plasma spray coating.

  16. Tuning negative refractive collimation beam by square lattice sonic crystal with concave incident surface

    Directory of Open Access Journals (Sweden)

    F. Shen

    2016-02-01

    Full Text Available Negative refractive collimation beam at the low frequency region is achieved in a square lattice sonic crystal with the small magnitude of effective refractive index. A simple tuning approach for such acoustic beam is also proposed by attaching an additional concave surface of incidence to the crystal slab. This can increase the propagation distance of collimation beam, enhance or suppress the beam intensity. The proposed approach is rather general and applicable to other acoustic materials as long as their effective index can be retrieved. Moreover, the results can be applied to wavefront manipulation and transmission enhancement.

  17. Microstructure evolution during surface alloying of ductile iron and austempered ductile iron by electron beam melting

    Science.gov (United States)

    Gulzar, A.; Akhter, J. I.; Ahmad, M.; Ali, G.; Mahmood, M.; Ajmal, M.

    2009-07-01

    Alloying and microstructural modification of surfaces by electron beam has become popular to tailor the surface properties of materials. Surface modification of as-received ductile iron, Ni-plated ductile iron and Ni-plated austempered ductile iron was carried out by electron beam melting to improve the surface properties. Martensitic structure evolved in the heat affected zone and ledeburite structure was produced in the molten zone of the ductile iron. Microhardness of the melted specimens enhanced considerably as compared to the as-received samples. However the microhardness of melted Ni-plated samples is lower than that of the unplated specimens. X-ray diffraction clearly revealed the formation of an austenite and Fe 3C phases in the electron beam molten zone. The broadening of peaks suggests refinement of the microstructure as well as internal stresses generated during electron beam melting.

  18. Microstructure evolution during surface alloying of ductile iron and austempered ductile iron by electron beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Gulzar, A. [Materials Division, Pakistan Institute of Nuclear Science and Technology, Nilore, Islamabad (Pakistan); Akhter, J.I. [Physics Division, Pakistan Institute of Nuclear Science and Technology, Nilore, Islamabad (Pakistan); Ahmad, M., E-mail: maqomer@yahoo.com [Physics Division, Pakistan Institute of Nuclear Science and Technology, Nilore, Islamabad (Pakistan); Ali, G. [Physics Division, Pakistan Institute of Nuclear Science and Technology, Nilore, Islamabad (Pakistan); Mahmood, M. [Department of Chemical and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences, Islamabad (Pakistan); Ajmal, M. [Department of Metallurgical and Materials Engineering, University of Engineering and Technology, Lahore (Pakistan)

    2009-07-30

    Alloying and microstructural modification of surfaces by electron beam has become popular to tailor the surface properties of materials. Surface modification of as-received ductile iron, Ni-plated ductile iron and Ni-plated austempered ductile iron was carried out by electron beam melting to improve the surface properties. Martensitic structure evolved in the heat affected zone and ledeburite structure was produced in the molten zone of the ductile iron. Microhardness of the melted specimens enhanced considerably as compared to the as-received samples. However the microhardness of melted Ni-plated samples is lower than that of the unplated specimens. X-ray diffraction clearly revealed the formation of an austenite and Fe{sub 3}C phases in the electron beam molten zone. The broadening of peaks suggests refinement of the microstructure as well as internal stresses generated during electron beam melting.

  19. Guide on the use of low energy electron beams for microbiological decontamination of surfaces

    DEFF Research Database (Denmark)

    Miller, Arne; Helt-Hansen, Jakob; Gondim, Ondina

    This Guide describes the validation and routine monitoring of microbiological decontamination of surfaces by low energy electron beams (100-200 keV). The Guide is mainly based on experience gained in connection with installation of electron beam systems for surface decontamination of pre-steriliz......This Guide describes the validation and routine monitoring of microbiological decontamination of surfaces by low energy electron beams (100-200 keV). The Guide is mainly based on experience gained in connection with installation of electron beam systems for surface decontamination of pre......-sterilized containers at several aseptic filling lines at pharmaceutical manufacturers. Its main emphasis is on the dosimetric measurements that should be carried out for the validation of the decontamination process and on establishing the appropriate effective dose. Other aspects such as use of measurement...... uncertainties and formation of radiation induced by-products are also addressed....

  20. Analysis of emissions from prebunched electron beams

    Directory of Open Access Journals (Sweden)

    Jia Qika

    2017-07-01

    Full Text Available The emissions of the prebunched electron beam, including the coherent spontaneous emission and the self-amplified stimulated emission, are analyzed by using one-dimensional FEL theory. Neglecting the interaction of the electrons and the radiation field, the formula of the coherent spontaneous emission is given, the power of which is proportional to the square of the initial bunching factor and of the undulator length. For the general emission case of the prebunched electron beam, the evolution equation of the optical field is deducted. Then the analytical expression of the emission power is obtained for the resonant case; it is applicable to the regions from the low gain to the high gain. It is found that when the undulator length is shorter than four gain lengths, the emission is just the coherent spontaneous emission, and conversely, it is the self-amplified stimulated emission growing exponentially. For the nonresonant prebunched electron beam, the variations of the emission intensity with the detuning parameter for different interaction length are presented. The radiation field characters of the prebunched electron beam are discussed and compared with that of the seeded FEL amplifier.

  1. Analysis of emissions from prebunched electron beams

    Science.gov (United States)

    Jia, Qika

    2017-07-01

    The emissions of the prebunched electron beam, including the coherent spontaneous emission and the self-amplified stimulated emission, are analyzed by using one-dimensional FEL theory. Neglecting the interaction of the electrons and the radiation field, the formula of the coherent spontaneous emission is given, the power of which is proportional to the square of the initial bunching factor and of the undulator length. For the general emission case of the prebunched electron beam, the evolution equation of the optical field is deducted. Then the analytical expression of the emission power is obtained for the resonant case; it is applicable to the regions from the low gain to the high gain. It is found that when the undulator length is shorter than four gain lengths, the emission is just the coherent spontaneous emission, and conversely, it is the self-amplified stimulated emission growing exponentially. For the nonresonant prebunched electron beam, the variations of the emission intensity with the detuning parameter for different interaction length are presented. The radiation field characters of the prebunched electron beam are discussed and compared with that of the seeded FEL amplifier.

  2. Performance based analysis of hidden beams in reinforced concrete structures

    Directory of Open Access Journals (Sweden)

    Helou Samir H.

    2014-01-01

    Full Text Available Local and perhaps regional vernacular reinforced concrete building construction leans heavily against designing slabs with imbedded hidden beams for flooring systems in most structures including major edifices. The practice is distinctive in both framed and in shear wall structures. Hidden beams are favoured structural elements due to their many inherent features that characterize them; they save on floor height clearance; they also save on formwork, labour and material cost. Moreover, hidden beams form an acceptable aesthetic appearance that does not hinder efficient interior space partitioning. Such beams have the added advantage of clearing the way for horizontal electromechanical ductwork. However, seismic considerations, in all likelihood, are seldom seriously addressed. The mentioned structural system of shallow beams is adopted in ribbed slabs, waffle slabs and at times with solid slabs. Ribbed slabs and waffle slabs are more prone to hidden beam inclusion due to the added effective height of the concrete section. Due to the presence of a relatively high reinforcement ratio at the joints the sections at such location tend to become less ductile with unreliable contribution to spandrel force resistance. In the following study the structural influence of hidden beams within slabs is investigated. With the primary focus on a performance based analysis of such elements within a structure. This is investigated with due attention to shear wall contribution to the overall behaviour of such structures. Numerical results point in the direction that the function of hidden beams is not as adequate as desired. Therefore it is strongly believed that they are generally superfluous and maybe eliminated altogether. Conversely, shallow beams seem to render the overall seismic capacity of the structure unreliable. Since such an argument is rarely manifested within the linear analysis domain; a pushover analysis exercise is thus mandatory for behaviour

  3. Low energy high current pulsed electron beam treatment for improving surface microstructure and properties

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J; Allain-Bonasso, N; Zhang, X D; Hao, S Z; Grosdider, T; Dong, C [Laboratoire d' Etude des Textures et Applications aux Materiaux (LETAM, UMR-CNRS 3143), Universite Paul Verlaine-Metz, Ile du Saulcy, 57045 Metz (France); Zou, J X, E-mail: jiang.wu@univ-metz.fr, E-mail: thierry.grosdidier@univ-metz.fr [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2010-06-15

    Low energy high current pulsed electron beam (LEHCPEB) is a fairly new technique for surface modifications authorizing improvement in wear and corrosion properties as well as texture changes and hardening. This contribution highlights some microstructure modifications encountered at the surface of HCPEB treated steels and bulk metallic glasses taking into account the effects of surface melting and the effects of the induced stress.

  4. From analysis to surface

    DEFF Research Database (Denmark)

    Bemman, Brian; Meredith, David

    2014-01-01

    of Sheer Pluck (1984), a twelve-tone composition for guitar by Milton Babbitt (1916–2011). This analysis focuses on the all-partition array structure on which the piece is based. Having pre- sented this analysis, we formalize some constraints on the structure of the piece and explore some computational...

  5. Large areas elemental mapping by ion beam analysis techniques

    Science.gov (United States)

    Silva, T. F.; Rodrigues, C. L.; Curado, J. F.; Allegro, P.; Moro, M. V.; Campos, P. H. O. V.; Santos, S. B.; Kajiya, E. A. M.; Rizzutto, M. A.; Added, N.; Tabacniks, M. H.

    2015-07-01

    The external beam line of the Laboratory for Material Analysis with Ion Beams (LAMFI) is a versatile setup for multi-technique analysis. X-ray detectors for Particle Induced X-rays Emission (PIXE) measurements, a Gamma-ray detector for Particle Induced Gamma- ray Emission (PIGE), and a particle detector for scattering analysis, such as Rutherford Backscattering Spectrometry (RBS), were already installed. In this work, we present some results, using a large (60-cm range) XYZ computer controlled sample positioning system, completely developed and build in our laboratory. The XYZ stage was installed at the external beam line and its high spacial resolution (better than 5 μm over the full range) enables positioning the sample with high accuracy and high reproducibility. The combination of a sub-millimeter beam with the large range XYZ robotic stage is being used to produce elemental maps of large areas in samples like paintings, ceramics, stones, fossils, and all sort of samples. Due to its particular characteristics, this is a unique device in the sense of multi-technique analysis of large areas. With the continuous development of the external beam line at LAMFI, coupled to the robotic XYZ stage, it is becoming a robust and reliable option for regular analysis of trace elements (Z > 5) competing with the traditional in-vacuum ion-beam-analysis with the advantage of automatic rastering.

  6. Measurements of the Surface Resistivity of a 99.99% Al/6063 Beam Pipe

    Science.gov (United States)

    Suetsugu, Yusuke; Ishimaru, Hajime

    1988-06-01

    The surface resistivity of a 99.99% Al/6063 beam pipe, which is proposed for vacuum chambers of the SSC (Superconducting Super Collider), was measured in the microwave frequency region at extremely low temperatures, near 10 K. The surface resistivity was found to be larger than that expected from the static resistivity, by a factor of 7, due to anomalous skin effects. Great attention should be paid in considering the beam impedance of the chamber at high frequencies.

  7. Anisotropic beam model for analysis and design of passive controlled wind turbine blades

    DEFF Research Database (Denmark)

    Branner, Kim; Blasques, José Pedro Albergaria Amaral; Kim, Taeseong

    . The developed fully coupled beam element and cross section analysis tool has been validated against both numerical calculations and experimental measurements. Numerical validation has been performed against beam type calculations including Variational Asymptotical Beam Section Analysis (VABS) and detailed shell...

  8. Controlling multipolar surface plasmon excitation through the azimuthal phase structure of electron vortex beams

    Science.gov (United States)

    Ugarte, Daniel; Ducati, Caterina

    2016-05-01

    We have theoretically studied how the azimuthal phase structure of an electron vortex beam excites surface plasmons on metal particles of different geometries as observed in electron energy loss spectroscopy (EELS). We have developed a semiclassical approximation combining a ring-shaped beam and the dielectric formalism. Our results indicate that for the case of total orbital angular momentum transfer, we can manipulate surface plasmon multipole excitation and even attain an enhancement factor of several orders of magnitude. Since electron vortex beams interact with particles mostly through effects due to azimuthal symmetry, i.e., in the plane perpendicular to the electron beam, anisotropy information (longitudinal and transversal) of the sample may be derived in EELS studies by comparing nonvortex and vortex beam measurements.

  9. Surface dose measurements and comparison of unflattened and flattened photon beams

    Directory of Open Access Journals (Sweden)

    Ashokkumar Sigamani

    2016-01-01

    Full Text Available The purpose of this study was to evaluate the central axis dose in the build-up region and the surface dose of a 6 MV and 10 MV flattened photon beam (FB and flattening filter free (FFF therapeutic photon beam for different square field sizes (FSs for a Varian Truebeam linear accelerator using parallel-plate ionization chamber and Gafchromic film. Knowledge of dosimetric characteristics in the build-up region and surface dose of the FFF is essential for clinical care. The dose measurements were also obtained empirically using two different commonly used dosimeters: a p-type photon semiconductor dosimeter and a cylindrical ionization chamber. Surface dose increased linearly with FS for both FB and FFF photon beams. The surface dose values of FFF were higher than the FB FSs. The measured surface dose clearly increases with increasing FS. The FFF beams have a modestly higher surface dose in the build-up region than the FB. The dependence of source to skin distance (SSD is less significant in FFF beams when compared to the flattened beams at extended SSDs.

  10. Cherenkov terahertz surface plasmon excitation by an electron beam over an ultrathin metal film

    Science.gov (United States)

    Kumar, Pawan; Kumar, Rajeev; Rajouria, Satish Kumar

    2016-12-01

    The mechanism of Cherenkov excitation of terahertz (THz) surface plasma wave (SPW), by a relativistic electron beam propagating over an ultrathin metal film deposited on glass, is investigated. The SPW field falls off exponentially in vacuum as well as glass, while the surface plasmon resonant frequency is lowered by the reduction of film thickness. The SPW field causes density bunching of the beam leading to current modulation and generation of THz radiation via the Cherenkov interaction. The frequency of the THz decreases with the energy of the beam, whereas the growth rate increases.

  11. Surface Modification of Light Alloys by Low-Energy High-Current Pulsed Electron Beam

    Directory of Open Access Journals (Sweden)

    X. D. Zhang

    2012-01-01

    Full Text Available This paper reviews results obtained by the research groups developing the low-energy high-current pulsed electron beam (LEHCPEB in Dalian (China and Metz (France on the surface treatment of light alloys. The pulsed electron irradiation induces an ultra-fast thermal cycle at the surface combined with the formation of thermal stress and shock waves. As illustrated for Mg alloys and Ti, this results in deep subsurface hardening (over several 100 μm which improves the wear resistance. The analysis of the top surface melted surface of light alloys also often witnesses evaporation and condensation of chemical species. This phenomenon can significantly modify the melt chemistry and was also suggested to lead to the development of specific solidification textures in the rapidly solidified layer. The potential use of the LEHCPEB technique for producing thermomechanical treatments under the so-called heating mode and, thus, modify the surface crystallographic texture, and enhance solid-state diffusion is also demonstrated in the case of the FeAl intermetallic compound.

  12. INVERSION OF ROUGHNESS PROFILE OF HETEROGENEOUS FRACTAL SURFACE USING GAUSSIAN BEAM INCIDENCE AT LOW GRAZING ANGLE

    Institute of Scientific and Technical Information of China (English)

    Jin Yaqin; Li Zhongxin

    2001-01-01

    As a Gaussian beam is incident upon a rough surface at low grazing angle, the Helmholts scalar wave equation may be replaced by the parabolic approximate equation. As the incident field is known, the scattered field and surface current give the Volterra integral equation.Surface roughness profile can be formulated by the integral equation of the surface currents. These two coupled equations are applied to invert the roughness profile of heterogeneous fractal surface.Using Monte Carlo method, the fractal rough surfaces with a band-limited Weistrass-Manderbrot function are numerically simulated and the scattered fields along a line parallel to the mean surface are solved. The Gaussian beam incidence and scattered fields are used to progressively invert the surface roughness profile. Reconstructed profile and its inverted fractal dimension,roughness variance and correlation length are well matched with the simulated surfaces.

  13. The Simple Lamb Wave Analysis to Characterize Concrete Wide Beams by the Practical MASW Test

    OpenAIRE

    Young Hak Lee; Taekeun Oh

    2016-01-01

    In recent years, the Lamb wave analysis by the multi-channel analysis of surface waves (MASW) for concrete structures has been an effective nondestructive evaluation, such as the condition assessment and dimension identification by the elastic wave velocities and their reflections from boundaries. This study proposes an effective Lamb wave analysis by the practical application of MASW to concrete wide beams in an easy and simple manner in order to identify the dimension and elastic wave veloc...

  14. Finite Element Vibration Analysis of Beams, Plates and Shells

    Directory of Open Access Journals (Sweden)

    Jaroslav Mackerle

    1999-01-01

    Full Text Available This bibliography lists references to papers, conference proceedings and theses/dissertations dealing with finite element vibration analysis of beams, plates and shells that were published in 1994–1998. It contains 361 citations. Also included, as separated subsections, are vibration analysis of composite materials and vibration analysis of structural elements with cracks/contacts.

  15. Surface Temperature Data Analysis

    Science.gov (United States)

    Hansen, James; Ruedy, Reto

    2012-01-01

    Small global mean temperature changes may have significant to disastrous consequences for the Earth's climate if they persist for an extended period. Obtaining global means from local weather reports is hampered by the uneven spatial distribution of the reliably reporting weather stations. Methods had to be developed that minimize as far as possible the impact of that situation. This software is a method of combining temperature data of individual stations to obtain a global mean trend, overcoming/estimating the uncertainty introduced by the spatial and temporal gaps in the available data. Useful estimates were obtained by the introduction of a special grid, subdividing the Earth's surface into 8,000 equal-area boxes, using the existing data to create virtual stations at the center of each of these boxes, and combining temperature anomalies (after assessing the radius of high correlation) rather than temperatures.

  16. Evanescent wave of extraordinary beam at uniaxial crystal surfaces

    Institute of Scientific and Technical Information of China (English)

    JIA Guang-yi

    2011-01-01

    Under the circumstance of optical axis being in the incident plane, the evanescent wave of total reflection is studied when an extraordinary beam is incident from an isotropic medium upon a uniaxial crystal by using the general characteristics ofuniaxial crystal and electromagnetic field. This paper presents the propagation directions of equiphase plane and the images of evanescent wave, and reveals that the equiamplitude plane and the equiphase plane are not in quadrature any more, and kept at 100%.

  17. A Pulse Power Modulator System for Commercial High Power Ion Beam Surface Treatment Applications

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, D.M.; Cockreham, B.D.; Dragt, A.J.; Ives, H.C.; Neau, E.L.; Reed, K.W.; White, F.E.

    1999-05-24

    The Ion Beam Surface Treatment (lBESTrM) process utilizes high energy pulsed ion beams to deposit energy onto the surface of a material allowing near instantaneous melting of the surface layer. The melted layer typically re-solidifies at a very rapid rate which forms a homogeneous, fine- grained structure on the surface of the material resulting in significantly improved surface characteristics. In order to commercialize the IBESTTM process, a reliable and easy-to-operate modulator system has been developed. The QM-I modulator is a thyratron-switched five-stage magnetic pulse compression network which drives a two-stage linear induction adder. The adder provides 400 kV, 150 ns FWHM pulses at a maximum repetition rate of 10 pps for the acceleration of the ion beam. Special emphasis has been placed upon developing the modulator system to be consistent with long-life commercial service.

  18. Use of Intense Ion Beams for Surface Modification and Creation of New Materials

    CERN Document Server

    Renk, T; Prasad, S V; Provencio, P P; Thompson, M

    2002-01-01

    We have conducted surface treatment and alloying experiments with Al, Fe, and Ti-based metals on the RHEPP-1 accelerator (0.8 MV, 20 W, 80 ns FHWM, up to 1 Hz repetition rate) at Sandia National Laboratories. Ions are generated by the MAP gas-breakdown active anode, which can yield a number of different beam species including H, N, and C, depending upon the injected gas. Beams of intense pulsed high-power ion beams have been used to produce surface modification by changes in microstructure caused by rapid heating and cooling of the surface. Increase of beam power leads to ablation of a target surface, and redeposition of ablated material onto a separate substrate. Experiments are described in which ion beams are used in an attempt to increase high-voltage breakdown of a treated surface. Surface alloying of coated Pt and Hf layers is also described. This mixing of a previously deposited thin-film layer into a Ti-alloy substrate leads to significantly enhanced surface wear durability, compared to either untreat...

  19. Scanning-probe-microscopy of polyethylene terephthalate surface treatment by argon ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza-Beltran, Francisco [Polymer & Biopolymer Group, Libramiento Norponiente no. 2000, Cinvestav Queretaro, Queretaro 76230 (Mexico); Sanchez, Isaac C. [Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712 (United States); España-Sánchez, Beatriz L.; Mota-Morales, Josué D.; Carrillo, Salvador; Enríquez-Flores, C.I. [Polymer & Biopolymer Group, Libramiento Norponiente no. 2000, Cinvestav Queretaro, Queretaro 76230 (Mexico); Poncin-Epaillard, Fabienne, E-mail: epaill@univ-lemans.fr [Institute for Molecules and Materials, UMR CNRS 6283, Av. O. Messiaen, Universitè du Maine, Le Mans 72085 (France); Luna-Barcenas, Gabriel, E-mail: gluna@qro.cinvestav.mx [Polymer & Biopolymer Group, Libramiento Norponiente no. 2000, Cinvestav Queretaro, Queretaro 76230 (Mexico)

    2015-11-01

    Highlights: • Kelvin-probe-force microscopy helps study of PET surface treated by Ar ion beam. • Ar ion beam surface treatment promotes chain scission and N insertion. • Surface roughness and work function increases as intensity of ion energy increases. • Adhesive force of PET decrease due to the surface changes by ion bombardment. - Abstract: The effect of argon (Ar{sup +}) ion beam treatment on the surface of polyethylene terephthalate (PET) samples was studied by scanning probe microscopy (SPM) and the changes in surface topography were assessed by atomic force microscopy (AFM). Kelvin probe force microscopy (KPFM) sheds light of adhesion force between treated polymer films and a Pt/Cr probe under dry conditions, obtaining the contact potential difference of material. As a result of Ar{sup +} ion bombardment, important surface chemical changes were detected by X-ray photoelectron spectroscopy (XPS) measurements such as chains scission and incorporation of nitrogen species. Ion beam treatment increases the surface roughness from 0.49 ± 0.1 nm to 7.2 ± 0.1 nm and modify the surface potential of PET samples, decreasing the adhesive forces from 12.041 ± 2.1 nN to 5.782 ± 0.06 nN, and producing a slight increase in the electronic work function (Φ{sub e}) from 5.1 V (untreated) to 5.2 V (treated). Ar{sup +} ion beam treatment allows to potentially changing the surface properties of PET, modifying surface adhesion, improving surface chemical changes, wetting properties and surface potential of polymers.

  20. Intense DC beam nonlinear transport-analysis & simulation

    Institute of Scientific and Technical Information of China (English)

    L(U) Jian-Qin; ZHAO Xiao-Song

    2009-01-01

    The intense dc beam nonlinear transport was analyzed with the Lie algebraic method,and the particle trajectories of the second order approximation were obtained.Based on the theoretical analysis a computer code was designed.To get self-consistent solutions,iteration procedures were used in the code.As an example,we calculated a beam line(drift-electrostatic quadrupole doublet-drift).The results agree to the results calculated by using the PIC method.

  1. Analysis of kicker noise induced beam emittance growth

    Energy Technology Data Exchange (ETDEWEB)

    Zhang W.; Sandberg, J.; Ahrens, L.; Blacker, I.M.; Brennan, M.; Blaskiewicz, M.; Fischer, W.; Hahn, H.; Huang, H.; Kling, N.; Lafky, M.; Marr, G.; Mernick, K.; Mi, J.; Minty, M.; Naylor, C.; Roser, T.; Shrey, T.; van Kuik, B.; Zelenski, A.

    2012-05-20

    Over the last few years, physicists have occasionally observed the presence of noise acting on the RHIC beams leading to emittance growth at high beam energies. While the noise was sporadic in the past, it became persistent during the Run-11 setup period. An investigation diagnosed the source as originating from the RHIC dump kicker system. Once identified the issue was quickly resolved. We report in this paper the investigation result, circuit analysis, measured and simulated waveforms, solutions, and future plans.

  2. Thermal analysis of reinforced concrete beams and frames

    Directory of Open Access Journals (Sweden)

    Essam H. El-Tayeb

    2017-04-01

    The obtained results of the studied cases reveal that material modeling of reinforced concrete beams and frames plays a major role in how these structures react to temperature variation. Cracking contributes to the release of significant portion of temperature restrain and in some cases this restrain is almost eliminated. The response of beams and frames deviates significantly based on the temperature gradient, linear or nonlinear; hence, the nonlinear temperature gradient which is the realistic profile is important to implement in the analysis.

  3. Applied surface analysis in magnetic storage technology

    Science.gov (United States)

    Windeln, Johannes; Bram, Christian; Eckes, Heinz-Ludwig; Hammel, Dirk; Huth, Johanna; Marien, Jan; Röhl, Holger; Schug, Christoph; Wahl, Michael; Wienss, Andreas

    2001-07-01

    This paper gives a synopsis of today's challenges and requirements for a surface analysis and materials science laboratory with a special focus on magnetic recording technology. The critical magnetic recording components, i.e. the protective carbon overcoat (COC), the disk layer structure, the read/write head including the giant-magnetoresistive (GMR) sensor, are described and options for their characterization with specific surface and structure analysis techniques are given. For COC investigations, applications of Raman spectroscopy to the structural analysis and determination of thickness, hydrogen and nitrogen content are discussed. Hardness measurements by atomic force microscopy (AFM) scratching techniques are presented. Surface adsorption phenomena on disk substrates or finished disks are characterized by contact angle analysis or so-called piezo-electric mass adsorption systems (PEMAS), also known as quartz crystal microbalance (QCM). A quickly growing field of applications is listed for various X-ray analysis techniques, such as disk magnetic layer texture analysis for X-ray diffraction, compositional characterization via X-ray fluorescence, compositional analysis with high lateral resolution via electron microprobe analysis. X-ray reflectometry (XRR) has become a standard method for the absolute measurement of individual layer thicknesses contained in multi-layer stacks and thus, is the successor of ellipsometry for this application. Due to the ongoing reduction of critical feature sizes, the analytical challenges in terms of lateral resolution, sensitivity limits and dedicated nano-preparation have been consistently growing and can only be met by state-of-the-art Auger electron spectrometers (AES), transmission electron microscopy (TEM) analysis, time-of-flight-secondary ion mass spectroscopy (ToF-SIMS) characterization, focused ion beam (FIB) sectioning and TEM lamella preparation via FIB. The depth profiling of GMR sensor full stacks was significantly

  4. Polishing superhard material surfaces with gas-cluster ion beams

    Science.gov (United States)

    Ieshkin, A. E.; Kushkina, K. D.; Kireev, D. S.; Ermakov, Yu. A.; Chernysh, V. S.

    2017-01-01

    We have studied the influence of bombardment with accelerated gas-cluster ions on the surface topography of silicon carbide and diamond. Atomic-force microscopy shows that exposure to 10-keV gas-cluster ions at a total dose above 1016 cm-2 leads to smoothing of the surface relief. The ion-etching rate and efficiency of the surface relief smoothing as dependent on the thickness of removed layer have been estimated. Raman-spectroscopy data show that surface irradiation with gas-cluster ions does not introduce defects into the crystalline structure of irradiated material.

  5. Converting surface plasmon polaritons into spatial bending beams through graded dielectric rectangles over metal film

    Science.gov (United States)

    Li, Hui; Xu, Yongzheng; Wang, Gang; Fu, Tong; Wang, Li; Zhang, Zhongyue

    2017-01-01

    Spatial bending beams, which preserve their spatial shape while propagating along curved trajectories in free space, offer important application in the fields of fiber sensor, optical trapping, and micromanipulation. In this work, two slits are designed on a metal film to excite surface plasmon polaritons (SPPs), and a group of dielectric rectangles over metal film is theoretically proposed to directly convert SPPs into spatial beams showing arbitrary bending. The appropriate locations of the dielectric rectangles are calculated by phase-modulation method. Transverse acceleration and nondiffraction characteristics of spatial bending beams are observed. We further demonstrate that the intensity distribution, shape, and propagation length of spatial beams showing arbitrary bending rely on structural parameters of dielectric rectangles and on the distance between dielectric rectangles and metal film. These findings provide guidance in the design and optimization of bending beam generators.

  6. Meniscus and beam halo formation in a tandem-type negative ion source with surface production

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Okuda, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

    2012-06-04

    A meniscus of plasma-beam boundary in H{sup -} ion sources largely affects the extracted H{sup -} ion beam optics. Although it is hypothesized that the shape of the meniscus is one of the main reasons for the beam halo observed in experiments, a physical mechanism of the beam halo formation is not yet fully understood. In this letter, it is first shown by the 2D particle in cell simulation that the H{sup -} ions extracted from the periphery of the meniscus cause a beam halo since the surface produced H{sup -} ions penetrate into the bulk plasma, and, thus, the resultant meniscus has a relatively large curvature.

  7. Nanopatterning of mobile lipid monolayers on electron-beam-sculpted Teflon AF surfaces.

    Science.gov (United States)

    Shaali, Mehrnaz; Lara-Avila, Samuel; Dommersnes, Paul; Ainla, Alar; Kubatkin, Sergey; Jesorka, Aldo

    2015-02-24

    Direct electron-beam lithography is used to fabricate nanostructured Teflon AF surfaces, which are utilized to pattern surface-supported monolayer phospholipid films with 50 nm lateral feature size. In comparison with unexposed Teflon AF coatings, e-beam-irradiated areas show reduced surface tension and surface potential. For phospholipid monolayer spreading experiments, these areas can be designed to function as barriers that enclose unexposed areas of nanometer dimensions and confine the lipid film within. We show that the effectiveness of the barrier is defined by pattern geometry and radiation dose. This surface preparation technique represents an efficient, yet simple, nanopatterning strategy supporting studies of lipid monolayer behavior in ultraconfined spaces. The generated structures are useful for imaging studies of biomimetic membranes and other specialized surface applications requiring spatially controlled formation of self-assembled, molecularly thin films on optically transparent patterned polymer surfaces with very low autofluorescence.

  8. Directional Characteristics of Thermal-Infrared Beaming from Atmosphereless Planetary Surfaces - A New Thermophysical Model

    CERN Document Server

    Rozitis, Ben

    2012-01-01

    We present a new rough-surface thermophysical model (Advanced Thermophysical Model or ATPM) that describes the observed directional thermal emission from any atmosphereless planetary surface. It explicitly incorporates partial shadowing, scattering of sunlight, selfheating and thermal-infrared beaming (re-radiation of absorbed sunlight back towards the Sun as a result of surface roughness). The model is verified by accurately reproducing ground-based directional thermal emission measurements of the lunar surface using surface properties that are consistent with the findings of the Apollo missions and roughness characterised by an RMS slope of ~32 degrees. By considering the wide range of potential asteroid surface properties, the model implies a beaming effect that cannot be described by a simple parameter or function. It is highly dependent on the illumination and viewing angles as well as surface thermal properties and is predominantly caused by macroscopic rather than microscopic roughness. Roughness alter...

  9. Rapid Melt and Resolidification of Surface Layers Using Intense, Pulsed Ion Beams Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Renk, Timothy J.

    1998-10-02

    The emerging technology of pulsed intense ion beams has been shown to lead to improvements in surface characteristics such as hardness and wear resistance, as well as mechanical smoothing. We report hereon the use of this technology to systematically study improvements to three types of metal alloys - aluminum, iron, and titanium. Ion beam tieatment produces a rapid melt and resolidification (RMR) of the surface layer. In the case of a predeposited thin-fihn layer, the beam mixes this layer into the substrate, Ieading to improvements that can exceed those produced by treatment of the alloy alone, In either case, RMR results in both crystal refinement and metastable state formation in the treated surface layer not accessible by conventional alloy production. Although more characterization is needed, we have begun the process of relating these microstructural changes to the surface improvements we discuss in this report.

  10. Modification of Teflon surface by proton microbeam and nitrogen ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Akane, E-mail: ogawa.akane@jaea.go.jp [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Satoh, Takahiro; Koka, Masashi; Kamiya, Tomihiro [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Kobayashi, Tomohiro [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 350-0198 (Japan)

    2013-11-01

    Teflon surfaces were modified using a combination of 3 MeV proton microbeam scanning and subsequent 250 keV N{sub 2}{sup +} ion beam irradiation. When a Teflon surface is irradiated using only an N{sub 2}{sup +} ion beam, micro-protrusions are densely formed in the irradiated area. It has been previously confirmed that these protrusions aid the attachment of biological cells, which then spread on the surface. Therefore, modification of the Teflon surface patterning is necessary in order to enhance its functionality as cell culture substrata. In this study, flat areas and depressed structures were created among the dense micro-protrusions by bubbles that were generated inside the sample using proton beam scanning. This modification will contribute to the fabrication of cell culture dishes with the advantages of micro-protrusions.

  11. Study of plasma formation in CW CO2 laser beam-metal surface interaction

    Science.gov (United States)

    Azharonok, V. V.; Vasilchenko, Zh V.; Golubev, Vladimir S.; Gresev, A. N.; Zabelin, Alexandre M.; Chubrik, N. I.; Shimanovich, V. D.

    1994-04-01

    An interaction of the cw CO2 laser beam and a moving metal surface has been studied. The pulsed and thermodynamical parameters of the surface plasma were investigated by optical and spectroscopical methods. The subsonic radiation wave propagation in the erosion plasma torch has been studied.

  12. Generation of Graphene Surface Plasmons and Their Applications in Beam Steering

    KAUST Repository

    Farhat, Mohamed

    2015-01-01

    We propose a novel concept that uses mechanical and electronic properties of graphene to efficiently couple light to surface plasmon polaritons. A graphene-based infrared beam-former based on the concept of surface leaky-wave is also discussed. © OSA 2015.

  13. Atomic Beam Laser Spectrometer for In-field Isotopic Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Alonso [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Actinide Analytical Chemistry Group

    2016-06-22

    This is a powerpoint presentation for the DTRA quarterly program review that goes into detail about the atomic beam laser spectrometer for in-field isotopic analysis. The project goals are the following: analysis of post-detonation debris, determination of U and Pu isotopic composition, and fieldable prototype: < 2ft3, < 1000W.

  14. Beam interactions with surface waves and higher-order modes in oversized backward wave oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Ogura, Kazuo; Kojima, Akihiko; Kawabe, Fumiaki; Yambe, Kiyoyuki [Niigata University, Niigata (Japan); Amin, Ruhul [Islamic University of Technology, Gazipur (Bangladesh)

    2014-10-15

    Beam interactions with surface waves and higher-order modes in an oversized backward wave oscillator (BWO) are studied. In addition to the well-known Cherenkov interaction, the slow cyclotron interaction occurs due to transverse perturbations of the electron beam. The Cherenkov interaction dominates the slow cyclotron interaction. Growth rates of both the interactions for the higher order modes are small compared with those for the surface-wave modes in an oversized BWO. The coaxial slow-wave structure exhibits a reduced number of higher-order modes, which consequently reduces the mode competition problem and improves beam interactions with higher order modes. For higher values of beam currents, the slow cyclotron wave grows at a faster rate than the Cherenkov waves.

  15. Electron beam analysis of particulate cometary material

    Science.gov (United States)

    Bradley, John

    1989-01-01

    Electron microscopy will be useful for characterization of inorganic dust grains in returned comet nucleus samples. The choice of instrument(s) will depend primarily on the nature of the samples, but ultimately a variety of electron-beam methods could be employed. Scanning and analytical (transmission) electron microscopy are the logical choise for morphological, mineralogical, and bulk chemical analyses of dust grains removed from ices. It may also be possible to examine unmelted ice/dust mixtures using an environmental scanning electron microscope equipped with a cryo-transfer unit and a cold stage. Electron microscopic observations of comet nuclei might include: (1) porosities of dust grains; (2) morphologies and microstructures of individual mineral grains; (3) relative abundances of olivine, pyroxene, and glass; and (4) the presence of phases that might have resulted from aqueous alteration (layer silicates, carbonates, sulfates).

  16. Surface modification of Al-Pb alloy by high current pulsed electron beam

    Institute of Scientific and Technical Information of China (English)

    LU You; LI Shi-long; AN Jian; LIU Yong-bing

    2006-01-01

    Al-Pb alloy was modified by high current pulsed electron beam and the microstructure, hardness and tribological characteristics were characterized by scanning electron microscopy, electronic microanalysis probe microanalysis, Knoop hardness indentation and pin-on-disc type wear testing machine. The results show that the microstructure and hardness can be greatly improved, and the modification layer consists of a molten zone, an overlapped zone of heat-affected and quasistatic thermal stress-affected zone and a transition zone followed by the substrate. The tribological properties of high current pulsed electron beam irradiated Al-Pb alloy are correspondingly improved largely. Optical observation and scanning electron microscopy analysis reveal that the low wear rate and lowest level in coefficient of friction at high load level for irradiated Al-Pb alloy are due to the formation of a lubricious tribolayer covering the worn surface, which is a mixture of Al2O3, Pb3O4 and silicate. The wear mode varies from oxidative wear at low load to film spalling at high load and, finally, adhesive wear.

  17. Non-vacuum electron-beam carburizing and surface hardening of mild steel

    Science.gov (United States)

    Bataev, I. A.; Golkovskii, M. G.; Losinskaya, A. A.; Bataev, A. A.; Popelyukh, A. I.; Hassel, T.; Golovin, D. D.

    2014-12-01

    In this paper, we study the structure, microhardness, and tribological properties of surface layers of mild (0.19% C) steel, which was formed by electron-beam cladding with an iron-graphite powder mixture followed by quenching and tempering. A 1.4 MeV electron beam that was extracted into air was used. Cladding of steel with the iron-graphite mixture at a beam current of 24 and 26 mA formed a hypoeutectic cast iron layer (2.19% C) and a hypereutectoid steel (1.57% C) layer, which were 2.0 and 2.6 mm thick, respectively. The microhardness of the surface-quenched and tempered steel and cast iron layers was 7 and 8 GPa, respectively. Electron-beam quenching of the surface layers of hypoeutectic cast iron was accompanied with multiple cracking. During the quenching of the 1.57% C steel layer, crack formation was not observed. In friction tests against fixed and loose abrasive particles, the surface layers of hypereutectoid steel and hypoeutectic cast iron that were produced by electron-beam cladding and quenching had lower wear rates than mild steel after pack carburizing, quenching, and tempering. In the sliding wear tests, the cast iron clad layer, which was subjected to electron-beam quenching and tempering, exhibited the highest wear resistance. Electron-beam treatment can be used to harden local areas of large workpieces. It is reasonable to treat clad layers of high-carbon steel with electron-beam quenching and tempering. To prevent multiple cracking, white cast iron layers should not be quenched.

  18. Technologies for Lunar Surface Power Systems Power Beaming and Transfer

    Science.gov (United States)

    Marzwell, Neville; Pogorzelski, Ronald J.; Chang, Kai; Little, Frank

    2008-01-01

    Wireless power transmission within a given working area is required or enabling for many NASA Exploration Systems. Fields of application include robotics, habitats, autonomous rendezvous and docking, life support, EVA, and many others. In robotics applications, for example, the robots must move in the working area without being hampered by power cables and, meanwhile, obtain a continuous and constant power from a power transmitter. The development of modern technology for transmitting electric power over free space has been studied for several decades, but its use in a system has been mainly limited to low power, 1-2 Vdc output voltage at a transmission distance of few meters for which relatively less than 0.5 mW/cm2 is required (e.g., Radio frequency identification RFID). Most of the rectenna conversion efficiency research to date has concentrated in low GHz frequency range of 2.45 to 10 GHz, with some work at 35 GHz. However, for space application, atmospheric adsorbtion is irrelevant and higher frequency systems with smaller transmit and receive apertures may be appropriate. For high power, most of the work on rectennas has concentrated on optimizing the conversion efficiency of the microwave rectifier element; the highest power demonstrated was 35 kW of power over a distance of 1.5 km. The objective of this paper is to establish the manner in which a very large number of very low power microwave devices can be synchronized to provide a beam of microwaves that can be used to efficiently and safely transport a significant amount of power to a remote location where it can be converted to dc (or ac) power by a ``rectenna.'' The proposed system is based on spatial power combining of the outputs of a large number of devices synchronized by mutual injection locking. We have demonstrated at JPL that such power could be achieved by combining 25 sources in a configuration that allows for convenient steering of the resulting beam of microwaves. Retrodirective beam

  19. Impact response of a Timoshenko-type viscoelastic beam considering the extension of its middle surface.

    Science.gov (United States)

    Rossikhin, Yury A; Shitikova, Marina V; Meza, Maria Guadalupe Estrada

    2016-01-01

    In the present paper, the problem of low-velocity impact of an elastic sphere against a viscoelastic Timoshenko-type beam is studied considering the extension of its middle surface. The viscoelastic features of the beam out of the contact domain are governed by the standard linear solid model with derivatives of integer order, while within the contact domain the fractional derivative standard linear solid model is utilized, in so doing rheological constants of the material in both models are the same. However the presence of the additional parameter, i.e. fractional parameter which could vary from zero to unit, allows one to vary beam's viscosity, since the structure of the beam's material within this zone may be damaged, resulting in the decrease of the beam material viscosity in the contact zone. Consideration for transient waves (surfaces of strong discontinuity) propagating in the target out of the contact zone via the theory of discontinuities and determination of the desired values behind the surfaces of discontinuities upto the contact domain with the help of ray series, as well as the utilization of the Hertz theory in the contact zone allow one to obtain a set of two integro-differential equations, which govern the desired values, namely: the local bearing of the target and impactor's materials and the displacement of the beam within the contact domain.

  20. Thin film depth profiling by ion beam analysis.

    Science.gov (United States)

    Jeynes, Chris; Colaux, Julien L

    2016-10-17

    The analysis of thin films is of central importance for functional materials, including the very large and active field of nanomaterials. Quantitative elemental depth profiling is basic to analysis, and many techniques exist, but all have limitations and quantitation is always an issue. We here review recent significant advances in ion beam analysis (IBA) which now merit it a standard place in the analyst's toolbox. Rutherford backscattering spectrometry (RBS) has been in use for half a century to obtain elemental depth profiles non-destructively from the first fraction of a micron from the surface of materials: more generally, "IBA" refers to the cluster of methods including elastic scattering (RBS; elastic recoil detection, ERD; and non-Rutherford elastic backscattering, EBS), nuclear reaction analysis (NRA: including particle-induced gamma-ray emission, PIGE), and also particle-induced X-ray emission (PIXE). We have at last demonstrated what was long promised, that RBS can be used as a primary reference technique for the best traceable accuracy available for non-destructive model-free methods in thin films. Also, it has become clear over the last decade that we can effectively combine synergistically the quite different information available from the atomic (PIXE) and nuclear (RBS, EBS, ERD, NRA) methods. Although it is well known that RBS has severe limitations that curtail its usefulness for elemental depth profiling, these limitations are largely overcome when we make proper synergistic use of IBA methods. In this Tutorial Review we aim to briefly explain to analysts what IBA is and why it is now a general quantitative method of great power. Analysts have got used to the availability of the large synchrotron facilities for certain sorts of difficult problems, but there are many much more easily accessible mid-range IBA facilities also able to address (and often more quantitatively) a wide range of otherwise almost intractable thin film questions.

  1. Residual Displacements‘ Progresive Analysis of the Multisupported Beam

    Directory of Open Access Journals (Sweden)

    Liudas Liepa

    2014-12-01

    Full Text Available This paper focuses on a shakedown behaviour of the ideally elasto-plastic beams system under variable repeated load. The mathematical models of the analysis problems are created using numerical methods, extremum energy principles and mathematic programming. It is shown that during the shakedown process the residual displacements vary non-monotonically. By solving analysis problem, where the load locus is being progressively expanded, it is possible to determine the upper and lower bounds of residual displacements. Suggested methods are ilustrated by solving multisupported beam example problem. The results are obtained considering principle of the small displacements.

  2. Hardening of graphite surface by ion beam amorphization

    Energy Technology Data Exchange (ETDEWEB)

    Hirvonen, J.P.; Stone, D.; Nastasi, M.; Hannula, S.P.

    1986-05-01

    Ion implantation has been shown to possess potential as a practical method for improving the mechanical properties of surfaces. So far a number of tests have been performed. In these studies, metals - most often steels or other hard materials - have been used. However, the improvement of the mechanical properties at the surface is not only important for substances that already have considerable hardness, but also for materials with other unique properties. Graphite is useful in many applications. Mechanically, it is easily machined and has good dimensional stability. It has self lubricity and under certain conditions has excellent sliding properties. Chemically, it is generally impermeable, resistant to corrosion, and compatable with mating materials. It is a good conductor of both heat and electrical current. The ion implantation of graphite has been studied elsewhere but without reference to the mechanical properties of the surface. It is expected, however, that heavy ion bombardment will cause structural changes at the graphite surface resulting in a modification of the mechanical properties. In this investigation the authors focus on these properties. The main objectives have been to study how the surface mechanical properties are changed by an ion bombardment and to find the relationship between mechanical properties and microstructure.

  3. Laser forming of a bowl shaped surface with a stationary laser beam

    Science.gov (United States)

    Chakraborty, Shitanshu Shekhar; More, Harshit; Nath, Ashish Kumar

    2016-02-01

    Despite a lot of research done in the field of laser forming, generation of a symmetric bowl shaped surface by this process is still a challenge mainly because only a portion of the sheet is momentarily deformed in this process, unlike conventional sheet metal forming like deep drawing where the entire blank undergoes forming simultaneously reducing asymmetry to a minimum. The motion of laser beam also makes the process asymmetric. To counter these limitations this work proposes a new approach for laser forming of a bowl shaped surface by irradiating the centre of a flat circular blank with a stationary laser beam. With high power lasers, power density sufficient for laser forming, can be availed at reasonably large spot sizes. This advantage is exploited in this technique. Effects of duration of laser irradiation and beam spot diameter on the amount of bending and asymmetry in the formed surface were investigated. Laser power was kept constant while varying irradiation time. While varying laser spot diameter laser power was chosen so as to keep the surface temperature nearly constant at just below melting. Experimental conditions promoted almost uniform heating through sheet thickness. The amount of bending increased with irradiation time and spot diameter. It was interesting to observe that blanks bent towards the laser beam for smaller laser beam diameters and the reverse happened for larger spot diameters (~10 times of the sheet thickness). Effect of spot diameter variation has been explained with the help of coupled thermal-structural finite element simulations.

  4. Analysis of beam plasma instability effects on incoherent scatter spectra

    Directory of Open Access Journals (Sweden)

    M. A. Diaz

    2010-12-01

    Full Text Available Naturally Enhanced Ion Acoustic Lines (NEIALs detected with Incoherent Scatter Radars (ISRs can be produced by a Langmuir decay mechanism, triggered by a bump on tail instability. A recent model of the beam-plasma instability suggests that weak-warm beams, such those associated with NEIAL events, might produce Langmuir harmonics which could be detected by a properly configured ISR. The analysis performed in this work shows that such a beam-driven wave may be simultaneously detected with NEIALs within the baseband signal of a single ISR. The analysis shows that simultaneous detection of NEIALs and the first Langmuir harmonic is more likely than simultaneous detection of NEIALs and enhanced plasma line. This detection not only would help to discriminate between current NEIAL models, but could also aid in the parameter estimation of soft precipitating electrons.

  5. In-beam activation analysis facility at MLZ, Garching

    Energy Technology Data Exchange (ETDEWEB)

    Révay, Zs., E-mail: zsolt.revay@frm2.tum.de [Heinz Maier-Leibniz Zentrum (MLZ), Technische Universität München, 85748 Garching (Germany); Kudějová, P.; Kleszcz, K.; Söllradl, S. [Heinz Maier-Leibniz Zentrum (MLZ), Technische Universität München, 85748 Garching (Germany); Genreith, Christoph [Heinz Maier-Leibniz Zentrum (MLZ), Technische Universität München, 85748 Garching (Germany); Institute of Energy and Climate Research, IEK-6: Nuclear Waste and Reactor Safety Fuel Cycle, Forschungszentrum Jülich GmbH in der Helmholtz-Gemeinschaft, 52428 Jülich (Germany)

    2015-11-01

    The reconstruction of the prompt gamma activation analysis facility and the construction of the new low-background counting chamber at MLZ, Garching is presented. The improvement of the shielding and its effect on the radiation background is shown. The setting up and the fine-tuning of the electronics and their characterization are also discussed. The upgraded facility has been demonstrated to be applicable for both PGAA and neutron activation analysis using in-beam activation and decay counting in the low-background counting chamber. - Highlights: • Radiation background at the PGAA facility was efficiently reduced. • In-beam irradiation facility in the strongest neutron beam. • The best signal-to-background ratio at a PGAA facility was achieved.

  6. Ion beam induced optical and surface modification in plasmonic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Udai B., E-mail: udaibhansingh123@gmail.com; Gautam, Subodh K.; Kumar, Sunil; Hooda, Sonu; Ojha, Sunil; Singh, Fouran

    2016-07-15

    In present work, ion irradiation induced nanostructuring has been exploited as an efficient and effective tool for synthesis of coupled plasmonics nanostructures by using 1.2 MeV Xe ions on Au/ZnO/Au system deposited on glass substrate. The results are correlated on the basis of their optical absorption, surface morphologies and enhanced sensitivity of evolved phonon modes by using UV Visible spectroscopy, scanning electron microscopy (SEM), and Raman spectroscopy (RS), respectively. Optical absorbance spectra of plasmonic nanostructures (NSs) show a decrease in band gap, which may be ascribed to the formation of defects with ion irradiation. The surface morphology reveals the formation of percolated NSs upon ion irradiation and Rutherford backscattering spectrometry (RBS) study clearly shows the formation of multilayer system. Furthermore, RS measurements on samples are studied to understand the enhanced sensitivity of ion irradiation induced phonon mode at 573 cm{sup −1} along with other modes. As compared to pristine sample, a stronger and pronounced evolution of these phonon modes is observed with further ion irradiation, which indicates localized surface plasmon results with enhanced intensity of phonon modes of Zinc oxide (ZnO) material. Thus, such plasmonic NSs can be used as surface enhanced Raman scattering (SERS) substrates.

  7. Surface nanostructuring of TiO{sub 2} thin films by ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Gomez, P. [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Cientificas, Universidad de Sevilla, c/Americo Vespucio 49, 41092 Sevilla (Spain); Palmero, A. [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Cientificas, Universidad de Sevilla, c/Americo Vespucio 49, 41092 Sevilla (Spain)], E-mail: alberto.palmero@icmse.csic.es; Yubero, F. [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Cientificas, Universidad de Sevilla, c/Americo Vespucio 49, 41092 Sevilla (Spain); Vinnichenko, M.; Kolitsch, A. [Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, POB 510119, 01314 Dresden (Germany); Gonzalez-Elipe, A.R. [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Cientificas, Universidad de Sevilla, c/Americo Vespucio 49, 41092 Sevilla (Spain)

    2009-04-15

    This work reports a procedure to modify the surface nanostructure of TiO{sub 2} anatase thin films through ion beam irradiation with energies in the keV range. Irradiation with N{sup +} ions leads to the formation of a layer with voids at a depth similar to the ion-projected range. By setting the ion-projected range a few tens of nanometers below the surface of the film, well-ordered nanorods appear aligned with the angle of incidence of the ion beam. Slightly different results were obtained by using heavier (S{sup +}) and lighter (B{sup +}) ions under similar conditions.

  8. Electron beam surface hardening of 42CrMo4 steel

    Energy Technology Data Exchange (ETDEWEB)

    Jokinen, T.; Meuronen, I. [Valmet Aviation Industries, Linnavuori (Finland). Engine Maintenance

    1997-12-31

    A study is reported in this paper which aims to find the proper parameters of an electron beam machine for using electron beam (EB) hardening on 42CrMo4 steel. Extended service life for engineering components depends on hard, wear resistant surfaces combined with tough base materials. EB hardening is particularly suitable to local treatment of complex components. Although surface hardening of 42CrMo4 steel was successful, careful optimization of process parameters and the hardened layer are required. (UK).

  9. Efficient out-coupling and beaming of Tamm optical states via surface plasmon polariton excitation

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Garcia, M.; Ho, Y.-L. D.; Taverne, M. P. C.; Chen, L.-F.; Rarity, J. G.; Oulton, R. [Department of Electrical and Electronic Engineering, University of Bristol, Faculty of Engineering, Queen' s Building, University Walk, Bristol BS8 1TR (United Kingdom); Murshidy, M. M. [Department of Physics and Mathematics, University of Hull, Cottingham Road, HU6 7RX Hull (United Kingdom); Department of Physics, Faculty of Science, Helwan University, Helwan (Egypt); Yousef Jameel Science and Technology Research Center, The American University in Cairo (Egypt); Edwards, A. P.; Adawi, A. M. [Department of Physics and Mathematics, University of Hull, Cottingham Road, HU6 7RX Hull (United Kingdom); Serry, M. Y. [Yousef Jameel Science and Technology Research Center, The American University in Cairo (Egypt)

    2014-06-09

    We present evidence of optical Tamm states to surface plasmon polariton (SPP) coupling. We experimentally demonstrate that for a Bragg stack with a thin metal layer on the surface, hybrid Tamm-SPP modes may be excited when a grating on the air-metal interface is introduced. Out-coupling via the grating to free space propagation is shown to enhance the transmission as well as the directionality and polarization selection for the transmitted beam. We suggest that this system will be useful on those devices, where a metallic electrical contact as well as beaming and polarization control is needed.

  10. STRUCTURAL ANALYSIS OF IN-PLANE LOADED CLT BEAMS

    Directory of Open Access Journals (Sweden)

    Mario Jeleč

    2017-01-01

    Full Text Available Cross laminated timber (CLT is a versatile engineered timber product that is increasingly well-known and of global interest in several applications such as full size plane or linear timber elements. The aim of this study involves investigating the performance of CLT beams loaded in-plane by considering bending and shear stress analysis with a special emphasis on the in-plane shear behavior including the complex internal structure of CLT. Numerical analysis based on 3D-FE models was used and compared with two existing analytical approaches, namely representative volume sub element (method I and composite beam theory (method II. The separate verification of bending and shear stresses including tree different shear failure modes was performed, and a good agreement was obtained. The main difference between the results relates to shear failure mode in the crossing areas between the orthogonally bonded lamellas in which the distribution of shear stresses τzx over the crossing areas per height of the CLT beam is not in accordance with the analytical assumptions. The presented analyses constitute the first attempt to contribute to the on-going review process of Eurocode 5 with respect to CLT beams loaded-in plane. Currently, regulations on designing these types of beams do not exist, and thus experimental and numerical investigations are planned in the future.

  11. Effects of evolving surface morphology on yield during focused ion beam milling of carbon

    Energy Technology Data Exchange (ETDEWEB)

    Adams, D.P. [Thin Film, Vacuum and Packaging Department, Sandia National Laboratories, P.O. Box 5800, MS 0959, Albuquerque, NM 87185 (United States)]. E-mail: dpadams@sandia.gov; Mayer, T.M. [Thin Film, Vacuum and Packaging Department, Sandia National Laboratories, P.O. Box 5800, MS 0959, Albuquerque, NM 87185 (United States); Vasile, M.J. [Thin Film, Vacuum and Packaging Department, Sandia National Laboratories, P.O. Box 5800, MS 0959, Albuquerque, NM 87185 (United States); Archuleta, K. [Thin Film, Vacuum and Packaging Department, Sandia National Laboratories, P.O. Box 5800, MS 0959, Albuquerque, NM 87185 (United States)

    2006-01-15

    We investigate evolving surface morphology during focused ion beam bombardment of C and determine its effects on sputter yield over a large range of ion dose (10{sup 17}-10{sup 19} ions/cm{sup 2}) and incidence angles ({theta} = 0-80{sup o}). Carbon bombarded by 20 keV Ga{sup +} either retains a smooth sputtered surface or develops one of two rough surface morphologies (sinusoidal ripples or steps/terraces) depending on the angle of ion incidence. For conditions that lead to smooth sputter-eroded surfaces there is no change in yield with ion dose after erosion of the solid commences. However, for all conditions that lead to surface roughening we observe coarsening of morphology with increased ion dose and a concomitant decrease in yield. A decrease in yield occurs as surface ripples increase wavelength and, for large {theta}, as step/terrace morphologies evolve. The yield also decreases with dose as rippled surfaces transition to have steps and terraces at {theta} = 75{sup o}. Similar trends of decreasing yield are found for H{sub 2}O-assisted focused ion beam milling. The effects of changing surface morphology on yield are explained by the varying incidence angles exposed to the high-energy beam.

  12. Three-dimensional elastic analysis of a composite double cantilever beam specimen

    Science.gov (United States)

    Raju, I. S.; Shivakumar, K. N.; Crews, J. H., Jr.

    1988-01-01

    Attention is given to the stresses and the strain energy release rate along the delamination front in the present three-dimensional elastic analysis of a 24-ply, cocured double-cantilever beam specimen by means of 20-noded parabolic-isoparametric finite elements. At the free surface, the strain energy release rate was found to be substantially smaller than the plane strain value; this is suggested to be due to the free-surface effect that exists where the delamination meets the surface edge.

  13. Ion beam technology applications study. [ion impact, implantation, and surface finishing

    Science.gov (United States)

    Sellen, J. M., Jr.; Zafran, S.; Komatsu, G. K.

    1978-01-01

    Specific perceptions and possible ion beam technology applications were obtained as a result of a literature search and contact interviews with various institutions and individuals which took place over a 5-month period. The use of broad beam electron bombardment ion sources is assessed for materials deposition, removal, and alteration. Special techniques examined include: (1) cleaning, cutting, and texturing for surface treatment; (2) crosslinking of polymers, stress relief in deposited layers, and the creation of defect states in crystalline material by ion impact; and (3) ion implantation during epitaxial growth and the deposition of neutral materials sputtered by the ion beam. The aspects, advantages, and disadvantages of ion beam technology and the competitive role of alternative technologies are discussed.

  14. Vibrational Energy Flow Analysis of Corrected Flexural Waves in Timoshenko Beam – Part II: Application to Coupled Timoshenko Beams

    Directory of Open Access Journals (Sweden)

    Young-Ho Park

    2006-01-01

    Full Text Available This paper presents the methodology for the energy flow analysis of coupled Timoshenko beam structures and various numerical applications to verify the developed methodology. To extend the application of the energy flow model for corrected flexural waves in the Timoshenko beam, which is developed in the other companion paper, to coupled structures, the wave transmission analyses of general coupled Timoshenko beam systems are performed. First, power transmission and reflection coefficients for all kinds of propagating waves in the general, coupled Timoshenko beam structures are derived by the wave transmission approach. In numerical applications, the energy flow solutions using the derived coefficients agree well with the classical solutions for various exciting frequencies, damping loss factors, and coupled Timoshenko beam structures. Additionally, the numerical results for the Timoshenko beam are compared with those for the Euler-Bernoulli beam.

  15. Limit Analysis of 3D Reinforced Concrete Beam Elements

    DEFF Research Database (Denmark)

    Larsen, Kasper P.; Nielsen, Leif Otto; Poulsen, Peter Noe

    2012-01-01

    A new finite-element framework for lower-bound limit analysis of reinforced concrete beams, subjected to loading in three dimensions, is presented. The method circumvents the need for a direct formulation of a complex section-force-based yield criterion by creating a discrete representation of th...

  16. 21st International Conference on Ion Beam Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Thevuthasan, Suntharampillai; Shutthanandan, V.; Wang, Yongqiang; Vizkelethy, Gyorgy; Rout, Bibhudutta

    2014-08-01

    This special issue of Nuclear Instruments and Methods in Physics Research B contains the proceedings of the 21st International Conference on Ion Beam Analysis (IBA – 2013). This conference was held in Marriott Waterfront in Seattle, Washington, USA during June 23–28, 2013.

  17. Dissipative instability of a highly relativistic electron beam through the excitation of surface waves on a conducting medium

    Energy Technology Data Exchange (ETDEWEB)

    Shokri, B. [Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Tehran (Iran, Islamic Republic of) and Institute for Studies in Theoretical Physics and Mathematics, P.O. Box 19395-1795, Tehran (Iran, Islamic Republic of)]. E-mail: b-shokri@cc.sbu.ac.ir; Khorashadizadeh, S.M. [Physics Department of Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Physics Department of Birjand University, Birjand (Iran, Islamic Republic of)

    2005-09-19

    The possibility of the dissipative instability of a relativistic electron beam streaming near a conducting medium is investigated. The development of this dissipative beam instability through the surface wave excitation slightly disturbs the beam leading to the slightly heating of the conducting medium.

  18. Analysis of shaking beam actuator for piezoelectric linear ultrasonic motor.

    Science.gov (United States)

    Lee, Kyongjai; Lee, Dong-Kyun; Borodinas, Sergejus; Vasiljev, Piotr; Nahm, Sahn; Yoon, Seok-Jin

    2004-11-01

    In this paper, piezoelectric linear ultrasonic motors (PLUM) have been investigated on the elliptic trajectory of a contact point in shaking beam, which has been accomplished by two resonance vibration modes of the actuators. The actuators have generated the vibration modes, longitudinal and flexural, by two longitudinal mechanical vibrations with phase difference of pi/2. Modal and harmonic analysis of the shaking beam actuator were performed by the finite element method (FEM) to calculate a resonance frequency and a modal shape and to perform harmonic response. Experimental results proved that a contact point of the PLUM tends to move with an elliptic trajectory.

  19. Water imaging in living plant by nondestructive neutron beam analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, M. Tomoko [Graduate School of Agricultural and Life Sciences, Univ. of Tokyo, Tokyo (Japan)

    1998-12-31

    Analysis of biological activity in intact cells or tissues is essential to understand many life processes. Techniques for these in vivo measurements have not been well developed. We present here a nondestructive method to image water in living plants using a neutron beam. This technique provides the highest resolution for water in tissue yet obtainable. With high specificity to water, this neutron beam technique images water movement in seeds or in roots imbedded in soil, as well as in wood and meristems during development. The resolution of the image attainable now is about 15um. We also describe how this new technique will allow new investigations in the field of plant research. (author)

  20. Beam instability in 980-nm power lasers: Experiment and analysis

    Science.gov (United States)

    Guthrie, James; Tan, G. L.; Ohkubo, M.; Fukushima, T.; Ikegami, Y.; Ijichi, T.; Irikawa, M.; Mand, R. S.; Xu, J. M.

    1994-12-01

    A theoretical analysis of beam instability (steering), commonly observed in high power ridge waveguide laser diodes is presented. A physical model of multiple interfering lateral modes is proposed and implemented in a two-dimensional self-consistent numerical code. It is shown that the dynamic evolution of the effective waveguide and the coherent lasing of emergent multiple lateral modes of the waveguide under high injection could lead to beam steering and knees in the fiber coupled L-I characteristics. The theory of simultaneous lasing and interaction between several lateral modes is found to be consistent with the observed back-plane radiation image.

  1. Excitation of surface plasmon polaritons by electron beam with graphene ribbon arrays

    Science.gov (United States)

    Liu, Yong-Qiang; Liu, Pu-Kun

    2017-03-01

    Graphene has emerged as an alternative material to support surface plasmon polaritons (SPPs) with its excellent properties such as the tight electromagnetic field localization, low dissipative loss, and versatile tunability. Thus, graphene surface plasmon polaritons (GSPs) provide an exciting platform to develop a series of novel devices and systems from the optical band to the terahertz (THz) band. In this paper, theoretical and simulated studies about the excitation of SPPs by an injected electron beam with periodic graphene ribbon arrays deposited on a dielectric medium are presented. The analytical dispersion expression of the GSP mode on the graphene ribbon arrays is obtained by using a modal expansion method along with periodic boundary conditions in the structure. With this result, the dispersion relation, propagation loss, and field pattern of the propagating GSPs for both periodic graphene microribbon arrays and the complete graphene sheet are investigated and analyzed in the THz band. It is shown that the electromagnetic field with a better concentration on the interface can be realized with graphene ribbon arrays compared with the graphene sheet for a given frequency. Besides, the excitation of GSPs by an injected electron beam with graphene ribbon arrays is modeled and implemented by the particle-in-cell simulation based on the finite difference time domain algorithm. GSPs can be excited effectively when the dispersion line of the electron beam and SPPs on the graphene ribbon arrays is matched with each other well. Besides, the dependences of output power on electron beam parameters such as the distance of the electron beam above the graphene ribbon surface and beam voltage are studied and analyzed. Finally, the tunability of graphene conductivity via biased voltage with a ground metal is considered and the tunable excitation of GSPs on the structure with biased drive voltage by the injected electron beam is also realized. The present work can find a

  2. Selective propagation and beam splitting of surface plasmons on metallic nanodisk chains.

    Science.gov (United States)

    Hu, Yuhui; Zhao, Di; Wang, Zhenghan; Chen, Fei; Xiong, Xiang; Peng, Ruwen; Wang, Mu

    2017-05-01

    Manipulating the propagation of surface plasmons (SPs) on a nanoscale is a fundamental issue of nanophotonics. By using focused electron beam, SPs can be excited with high spatial accuracy. Here we report on the propagation of SPs on a chain of gold nanodisks with cathodoluminescence (CL) spectroscopy. Experimental evidence for the propagation of SPs excited by the focused electron beam is demonstrated. The wavelength of the transmitted SPs depends on the geometrical parameters of the nanodisk chain. Furthermore, we design and fabricate a beam splitter, which selectively transmits SPs of certain wavelengths to a specific direction. By scanning the sample surface point by point and collecting the CL spectra, we obtain the spectral mapping and identify that the chain of the smaller nanodisks can efficiently transport SPs at shorter wavelengths. This Letter provides a unique approach to manipulate in-plane propagation of SPs.

  3. Finite element analysis of rotating beams physics based interpolation

    CERN Document Server

    Ganguli, Ranjan

    2017-01-01

    This book addresses the solution of rotating beam free-vibration problems using the finite element method. It provides an introduction to the governing equation of a rotating beam, before outlining the solution procedures using Rayleigh-Ritz, Galerkin and finite element methods. The possibility of improving the convergence of finite element methods through a judicious selection of interpolation functions, which are closer to the problem physics, is also addressed. The book offers a valuable guide for students and researchers working on rotating beam problems – important engineering structures used in helicopter rotors, wind turbines, gas turbines, steam turbines and propellers – and their applications. It can also be used as a textbook for specialized graduate and professional courses on advanced applications of finite element analysis.

  4. Invariant and energy analysis of an axially retracting beam

    Institute of Scientific and Technical Information of China (English)

    Yang Xiaodong; Liu Ming; Zhang Wei; Roderick V.N. Melnik

    2016-01-01

    The mechanism of a retracting cantilevered beam has been investigated by the invariant and energy-based analysis. The time-varying parameter partial differential equation governing the transverse vibrations of a beam with retracting motion is derived based on the momentum theorem. The assumed-mode method is used to truncate the governing partial differential equation into a set of ordinary differential equations (ODEs) with time-dependent coefficients. It is found that if the order of truncation is not less than the order of the initial conditions, the assumed-mode method can yield accurate results. The energy transfers among assumed modes are discussed during retrac-tion. The total energy varying with time has been investigated by numerical and analytical methods, and the results have good agreement with each other. For the transverse vibrations of the axially retracting beam, the adiabatic invariant is derived by both the averaging method and the Bessel function method.

  5. Surface optical phonons in GaAs nanowires grown by Ga-assisted chemical beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    García Núñez, C., E-mail: carlos.garcia@uam.es; Braña, A. F.; Pau, J. L.; Ghita, D.; García, B. J. [Grupo de Electrónica y Semiconductores, Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Shen, G.; Wilbert, D. S.; Kim, S. M.; Kung, P. [Department of Electrical and Computer Engineering, The University of Alabama, Tuscaloosa, Alabama 35487 (United States)

    2014-01-21

    Surface optical (SO) phonons were studied by Raman spectroscopy in GaAs nanowires (NWs) grown by Ga-assisted chemical beam epitaxy on oxidized Si(111) substrates. NW diameters and lengths ranging between 40 and 65 nm and between 0.3 and 1.3 μm, respectively, were observed under different growth conditions. The analysis of the Raman peak shape associated to either longitudinal or surface optical modes gave important information about the crystal quality of grown NWs. Phonon confinement model was used to calculate the density of defects as a function of the NW diameter resulting in values between 0.02 and 0.03 defects/nm, indicating the high uniformity obtained on NWs cross section size during growth. SO mode shows frequency downshifting as NW diameter decreases, this shift being sensitive to NW sidewall oxidation. The wavevector necessary to activate SO phonon was used to estimate the NW facet roughness responsible for SO shift.

  6. Finite Element Analysis of a Natural Fiber (Maize Composite Beam

    Directory of Open Access Journals (Sweden)

    D. Saravana Bavan

    2013-01-01

    Full Text Available Natural fiber composites are termed as biocomposites or green composites. These fibers are green, biodegradable, and recyclable and have good properties such as low density and low cost when compared to synthetic fibers. The present work is investigated on the finite element analysis of the natural fiber (maize composite beam, processed by means of hand lay-up method. Composite beam material is composed of stalk-based fiber of maize and unsaturated polyester resin polymer as matrix with methyl ethyl ketone peroxide (MEKP as a catalyst and Cobalt Octoate as a promoter. The material was modeled and resembled as a structural beam using suitable assumption and analyzed by means of finite element method using ANSYS software for determining the deflection and stress properties. Morphological analysis and X-ray diffraction (XRD analysis for the fiber were examined by means of scanning electron microscope (SEM and X-ray diffractometer. From the results, it has been found that the finite element values are acceptable with proper assumptions, and the prepared natural fiber composite beam material can be used for structural engineering applications.

  7. Vibrational Energy Flow Analysis of Corrected Flexural Waves in Timoshenko Beam – Part II: Application to Coupled Timoshenko Beams

    OpenAIRE

    2006-01-01

    This paper presents the methodology for the energy flow analysis of coupled Timoshenko beam structures and various numerical applications to verify the developed methodology. To extend the application of the energy flow model for corrected flexural waves in the Timoshenko beam, which is developed in the other companion paper, to coupled structures, the wave transmission analyses of general coupled Timoshenko beam systems are performed. First, power transmission and reflection coefficients for...

  8. Non-vacuum electron-beam carburizing and surface hardening of mild steel

    Energy Technology Data Exchange (ETDEWEB)

    Bataev, I.A., E-mail: ivanbataev@ngs.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Golkovskii, M.G., E-mail: M.G.Golkovski@inp.nsk.su [Budker Institute of Nuclear Physics SB RAS, Lavrentieva Prospect 11, 630090 Novosibirsk (Russian Federation); Losinskaya, A.A., E-mail: anna.losinskaya@mail.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Bataev, A.A., E-mail: bataev@adm.nstu.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Popelyukh, A.I., E-mail: aip13@mail.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Hassel, T., E-mail: hassel@iw.uni-hannover.de [Leibniz University, Welfengarten 1, 30167 Hannover (Germany); Golovin, D.D., E-mail: ddgolovin@yandex.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation)

    2014-12-15

    Highlights: • Steel specimens were carburized by non-vacuum electron-beam cladding. • The depth of the clad layers reached 2.6 mm. • The cladding rate was 1.8 m{sup 2}/h, the quenching rate 12.6 m{sup 2}/h. • The microhardness of the quenched and tempered layers reached 8 GPa. - Abstract: In this paper, we study the structure, microhardness, and tribological properties of surface layers of mild (0.19% C) steel, which was formed by electron-beam cladding with an iron–graphite powder mixture followed by quenching and tempering. A 1.4 MeV electron beam that was extracted into air was used. Cladding of steel with the iron–graphite mixture at a beam current of 24 and 26 mA formed a hypoeutectic cast iron layer (2.19% C) and a hypereutectoid steel (1.57% C) layer, which were 2.0 and 2.6 mm thick, respectively. The microhardness of the surface-quenched and tempered steel and cast iron layers was 7 and 8 GPa, respectively. Electron-beam quenching of the surface layers of hypoeutectic cast iron was accompanied with multiple cracking. During the quenching of the 1.57% C steel layer, crack formation was not observed. In friction tests against fixed and loose abrasive particles, the surface layers of hypereutectoid steel and hypoeutectic cast iron that were produced by electron-beam cladding and quenching had lower wear rates than mild steel after pack carburizing, quenching, and tempering. In the sliding wear tests, the cast iron clad layer, which was subjected to electron-beam quenching and tempering, exhibited the highest wear resistance. Electron-beam treatment can be used to harden local areas of large workpieces. It is reasonable to treat clad layers of high-carbon steel with electron-beam quenching and tempering. To prevent multiple cracking, white cast iron layers should not be quenched.

  9. In situ photoelectron spectroscopy of molecular-beam-epitaxy grown surfaces

    CERN Document Server

    Oshima, M; Okabayashi, J; Ono, K

    2003-01-01

    Two in situ high-resolution synchrotron radiation photoelectron spectroscopy (SRPES) systems combined with a molecular beam epitaxy (MBE) chamber for III-V compound semiconductors and a laser MBE chamber for strongly correlated oxide films, respectively, have been designed and fabricated to analyze intrinsic and surface/interface electronic structures of these unique materials. The importance of the in situ SRPES has been demonstrated by the results of 1) Si surface nanostructures, 2) GaAs surfaces/interfaces and nanostructures, 3) MnAs magnetic nanostructures, and 4) strongly-correlated La sub 1 sub - sub x Sr sub x MnO sub 3 surfaces/interfaces and superstructures.

  10. Timoshenko beam model for buckling of piezoelectric nanowires with surface effects.

    Science.gov (United States)

    Samaei, Arash Tourki; Bakhtiari, Majid; Wang, Gang-Feng

    2012-03-27

    This paper investigates the buckling behavior of piezoelectric nanowires under distributed transverse loading, within the framework of the Timoshenko beam theory, and in the presence of surface effects. Analytical relations are given for the critical force of axial buckling of nanowires by accounting for the effects of surface elasticity, residual surface tension, and transverse shear deformation. Through an example, it is shown that the critical electric potential of buckling depends on both the surface stresses and piezoelectricity. This study may be helpful in the characterization of the mechanical properties of nanowires and in the calibration of the nanowire-based force sensors.

  11. Experimental and statistical models of impact determination of the electron beam parameters on surface layers properties of optical elements in precision instruments building

    Directory of Open Access Journals (Sweden)

    I.V. Yatsenko

    2016-05-01

    Full Text Available Modern devices with optical elements for measurement and thermal control of different physical nature objects subjected to intense external thermal actions. To prevent destruction of optical elements the electron beam methods of work surfaces finishing at the stage of manufacture has practical significance. These methods can improve the properties of the element surface layers and thus make them more resistant to external thermal and mechanical action. Aim: The aim is to determine the optimal ranges of parameters of the electron beam and the development of experimental and statistical models that will automatically generate database with improved properties of the surface layers of optical elements in real time mode after previous electron beam treatment. Materials and Methods: To study the influence of parameters of the electron beam on the properties of the surface layers of the optical elements used plates of optical glass (K8, K108, etc. and ceramics (KO1, KO2, etc.. The strip electron beam has the following characteristics: density of heat flow Fn = 5∙10^6…9∙10^8 W/m2 and rate of displacement V = 0…0.1 m/s. Determination of the surface layers properties of the optical elements before and after electron beam treatment was carried out by known methods of physical and chemical analysis. Results: It was established that under the influence of the electron beam on the surface of the optical element there is visible clearing of various impurities take place, various micro-defects that remain on it after standard processing methods (mechanical, chemical, etc. remove and also its smoothness significantly increases, i.e. height of residual asperities on the surface is reduced. It was also found that the processing of optical glass elements by electron beam their surface layers change their structure, which is close to the quartz. It is shown that the surface of the preprocessed electron beam elements able to withstand the critical value of

  12. Luminescence effects of ion-beam bombardment of CdTe surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Olvera, J., E-mail: javier.olvera@uam.e [Laboratorio de Crecimiento de Cristales, Dpto. de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Martinez, O. [Optronlab Group, Dpto. Fisica Materia Condensada, Edificio I-D, Universidad de Valladolid, Paseo de Belen 1, 47011 Valladolid (Spain); Plaza, J.L.; Dieguez, E. [Laboratorio de Crecimiento de Cristales, Dpto. de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2009-09-15

    In the present work, we report the effect of low-energy ion bombardment on CdTe surfaces. The effect is revealed by FESEM images and photoluminescence (PL) measurements carried out before and after irradiation of CdTe polycrystals by means of an ion-beam sputtering (IBS) system. An important improvement in the luminescence of CdTe was observed in the irradiated areas, related to defect-free surfaces.

  13. Weld Decay Recovery by Laser Beam Surfacing of Austenitic Stainless Steel Welded Joints

    OpenAIRE

    Isao, MASUMOTO; Takeshi, SHINODA; Toshimasa, HIRATE; Nagoya University, currently at Gifu Vocational Training College; Faculty of Engineering, Nagoya University; Nagoya University, currently at Toshiba Co. Ltd.

    1990-01-01

    This study is an attempt to improve corrosion resistance by laser beam surface treatment. AISI 304 type stainless steel welds were surface treated by laser and the effectivenesses of various treatment conditions were evaluated by acidic corrosion tests and metallurgical observation. It was found that laser treatment changed the morphology of carbide precipitates in the heat affected zone of AISI 304 austenitic steel MIG welded joints, and that it is possible to effect revovery from weld decay...

  14. The surface roughness of (433) Eros as measured by thermal-infrared beaming

    Science.gov (United States)

    Rozitis, B.

    2017-01-01

    In planetary science, surface roughness is regarded to be a measure of surface irregularity at small spatial scales, and causes the thermal-infrared beaming effect (i.e. re-radiation of absorbed sunlight back towards to the Sun). Typically, surface roughness exhibits a degeneracy with thermal inertia when thermophysical models are fitted to disc-integrated thermal-infrared observations of asteroids because of this effect. In this work, it is demonstrated how surface roughness can be constrained for near-Earth asteroid (433) Eros (i.e. the target of NASA's NEAR Shoemaker mission) when using the Advanced Thermophysical Model with thermal-infrared observations taken during an `almost pole-on' illumination and viewing geometry. It is found that the surface roughness of (433) Eros is characterized by an rms slope of 38 ± 8° at the 0.5-cm spatial scale associated with its thermal-infrared beaming effect. This is slightly greater than the rms slope of 25 ± 5° implied by the NEAR Shoemaker laser ranging results when extrapolated to this spatial scale, and indicates that other surface shaping processes might operate, in addition to collisions and gravity, at spatial scales under one metre in order to make asteroid surfaces rougher. For other high-obliquity asteroids observed during `pole-on' illumination conditions, the thermal-infrared beaming effect allows surface roughness to be constrained when the sub-solar latitude is greater than 60°, and if the asteroids are observed at phase angles of less than 40°. They will likely exhibit near-Earth asteroid thermal model beaming parameters that are lower than expected for a typical asteroid at all phase angles up to 100°.

  15. Low energy ion beam modification of Cu/Ni/Si(100) surface

    Indian Academy of Sciences (India)

    S K Parida; V R Rmedicherla; D K Mishra; S Choudhary; V Solanki; Shikha Varma

    2014-12-01

    Cu/Ni bilayer has been prepared by thermal evaporation of pure Cu and Ni metals onto Si(100) surface in high vacuum; it was sputtered using argon ion beam in ultra-high vacuum. The ion beam-induced surface and interface modification was investigated using X-ray photoelectron spectroscopy and atomic force microscopy techniques. The deposited sample exhibits the formation of CuO nano-structures of size 40 nm on Cu surface and after sputtering with argon ion beam at a fluence of 5 × 1015 ions/cm2, the surface exhibits a mound structure with an average size of about 100 nm. Interestingly, with sputtering at higher fluence of 2.4 × 1016 ions/cm2, the surface exhibits broad pits of sizes ranging from 100 to 300 nm with an average depth of 10 nm. Bottom surface of these pits contains Ni atoms. The Cu 23/2 peak exhibits a shift of 0.3 eV towards high binding energy and also a large asymmetry of 0.11 after sputtering at high fluence compared with pure copper. These changes are attributed to Cu–Ni interactions at the interface.

  16. Tuning beam power-splitting characteristics through modulating a photonic crystal slab’s output surface

    Science.gov (United States)

    Feng, Shuai; Xiao, Ting-Hui; Gan, Lin; Wang, Yi-Quan

    2017-01-01

    Light-beam-splitting characteristics are theoretically and experimentally studied in 2D square-lattice photonic crystals (PhCs) with delicately designed and modulated output surfaces. Compared with the traditional branch-waveguide and self-collimation-type PhC splitters, our proposed structure can not only split the input light beam into different numbers of branches but also realize the adjustment of their relative light intensities in each branch. Moreover, the influence of a light beam’s incident angle on both the output branch beams’ relative intensity and propagation direction is investigated. This proposed light beam splitter is able to work within a broad frequency range, and the propagation directions of the output split beams can be modified with the incident beam’s frequency. In addition, when the PhC device becomes thicker, a kind of light-beam-focusing phenomenon is observed. Advantageously, our light-beam-splitting device has no restriction as to the incident light beam’s location and width, so it is much more convenient and practical for achieving optical connection with other functional devices in complicated, large-scale, all-optical integrated circuits.

  17. Light and heavy ion beam analysis of thin biological sections

    Science.gov (United States)

    Lee, Joonsup; Siegele, Rainer; Pastuovic, Zeljko; Hackett, Mark J.; Hunt, Nicholas H.; Grau, Georges E.; Cohen, David D.; Lay, Peter A.

    2013-07-01

    The application of ion beam analysis (IBA) techniques to thin biological sections (ThBS) presents unique challenges in sample preparation, data acquisition and analysis. These samples are often the end product of expensive, time-consuming experiments, which involve many steps that require careful attention. Analysis via several techniques can maximise the information that is collected from these samples. Particle-induced X-ray emission (PIXE) and Rutherford backscattering (RBS) spectroscopy are two generally non-destructive IBA techniques that use the same MeV ions and can be performed simultaneously. The use of heavy ion PIXE applied to thick samples has, in the past, resulted in X-ray spectra of a poorer quality when compared to those obtained with proton beams. One of the reasons for this is the shorter probing depth of the heavy ions, which does not affect thin sample analysis. Therefore, we have investigated and compared 3-MeV proton and 36-MeV carbon ion beams on 7-μm thick mouse brain sections at the ANSTO Heavy ion microprobe (HIMP). The application of a 36-MeV C4+ ion beam for PIXE mapping of ThBS on thin Si3N4 substrate windows produced spectra of high quality that displayed close to a nine-times gain in signal yield (Z2/q) when compared to those obtained for 3-MeV protons for P, S, Cl and K but not for Fe, Cu and Zn. Image quality was overall similar; however, some elements showed better contrast and features with protons whilst others showed improved contrast with a carbon ion beam. RBS spectra with high enough counting statistics were easily obtained with 3-MeV proton beams resulting in high resolution carbon maps, however, the count rate for nitrogen and oxygen was too low. The results demonstrate that on thin samples, 36-MeV C4+ will produce good quality PIXE spectra in less time; therefore, carbon ions may be advantageous depending on which element is being studied. However, these advantages may be outweighed by the inherent disadvantages including

  18. Light and heavy ion beam analysis of thin biological sections

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joonsup, E-mail: joonsup.lee@sydney.edu.au [School of Chemistry, The University of Sydney, NSW 2006 (Australia); Siegele, Rainer, E-mail: rainer.siegele@ansto.gov.au [Institute for Environmental Research, ANSTO, NSW 2234 (Australia); Pastuovic, Zeljko, E-mail: zeljko.pastuovic@ansto.gov.au [Institute for Environmental Research, ANSTO, NSW 2234 (Australia); Hackett, Mark J., E-mail: mark.hackett@usask.ca [School of Chemistry, The University of Sydney, NSW 2006 (Australia); Hunt, Nicholas H., E-mail: nhunt@med.usyd.edu.au [Molecular Immunopathology Unit, Bosch Institute and School of Medical Sciences, The University of Sydney, NSW 2006 (Australia); Grau, Georges E., E-mail: georges.grau@sydney.edu.au [Vascular Immunology Unit, Bosch Institute and School of Medical Sciences, The University of Sydney, NSW 2006 (Australia); Cohen, David D., E-mail: david.cohen@ansto.gov.au [Institute for Environmental Research, ANSTO, NSW 2234 (Australia); Lay, Peter A., E-mail: peter.lay@sydney.edu.au [School of Chemistry, The University of Sydney, NSW 2006 (Australia)

    2013-07-01

    The application of ion beam analysis (IBA) techniques to thin biological sections (ThBS) presents unique challenges in sample preparation, data acquisition and analysis. These samples are often the end product of expensive, time-consuming experiments, which involve many steps that require careful attention. Analysis via several techniques can maximise the information that is collected from these samples. Particle-induced X-ray emission (PIXE) and Rutherford backscattering (RBS) spectroscopy are two generally non-destructive IBA techniques that use the same MeV ions and can be performed simultaneously. The use of heavy ion PIXE applied to thick samples has, in the past, resulted in X-ray spectra of a poorer quality when compared to those obtained with proton beams. One of the reasons for this is the shorter probing depth of the heavy ions, which does not affect thin sample analysis. Therefore, we have investigated and compared 3-MeV proton and 36-MeV carbon ion beams on 7-μm thick mouse brain sections at the ANSTO Heavy ion microprobe (HIMP). The application of a 36-MeV C{sup 4+} ion beam for PIXE mapping of ThBS on thin Si{sub 3}N{sub 4} substrate windows produced spectra of high quality that displayed close to a nine-times gain in signal yield (Z{sup 2}/q) when compared to those obtained for 3-MeV protons for P, S, Cl and K but not for Fe, Cu and Zn. Image quality was overall similar; however, some elements showed better contrast and features with protons whilst others showed improved contrast with a carbon ion beam. RBS spectra with high enough counting statistics were easily obtained with 3-MeV proton beams resulting in high resolution carbon maps, however, the count rate for nitrogen and oxygen was too low. The results demonstrate that on thin samples, 36-MeV C{sup 4+} will produce good quality PIXE spectra in less time; therefore, carbon ions may be advantageous depending on which element is being studied. However, these advantages may be outweighed by the

  19. Dosimetric measurements and Monte Carlo simulation for achieving uniform surface dose in pulsed electron beam irradiation facility

    Indian Academy of Sciences (India)

    V C Petwal; J N Rao; Jishnu Dwivedi; V K Senecha; K V Subbaiah

    2010-03-01

    A prototype pulsed electron beam irradiation facility for radiation processing of food and medical products is being commissioned at our centre in Indore, India. Analysis of surface dose and uniformity for a pulsed beam facility is of crucial importance because it is influenced by various operating parameters such as beam current, pulse repetition rate (PRR), scanning current profile and frequency, scanning width and product conveying speed. A large number of experiments are required to determine the harmonized setting of these operating parameters for achieving uniform dose. Since there is no readily available tool to set these parameters, use of Monte Carlo methods and computational tools can prove to be the most viable and time saving technique to support the assessment of the dose distribution. In the present study, Monte Carlo code, MCNP, is used to simulate the transport of 10 MeV electron beam through various mediums coming into the beam path and generate an equivalent dose profile in a polystyrene phantom for stationary state. These results have been verified with experimentally measured dose profile, showing that results are in good agreement within 4%. The Monte Carlo simulation further has been used to optimize the overlapping between the successive pulses of a scan to achieve ± 5% dose uniformity along the scanning direction. A mathematical model, which uses the stationary state data, is developed to include the effect of conveyor speed. The algorithm of the model is discussed and the results are compared with the experimentally measured values, which show that the agreement is better than 15%. Finally, harmonized setting for operating parameters of the accelerator are derived to deliver uniform surface dose in the range of 1–13 kGy/pass.

  20. New accelerators for femtosecond beam pump-and-probe analysis

    Energy Technology Data Exchange (ETDEWEB)

    Uesaka, Mitsuru [Nuclear Engineering Research Laboratory, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan)]. E-mail: uesaka@utnl.jp; Sakumi, Akira [Nuclear Engineering Research Laboratory, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Hosokai, Tomonao [Nuclear Engineering Research Laboratory, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Kinoshita, Kenichi [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Yamaoka, Nobuaki [Nuclear Engineering Research Laboratory, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Zhidkov, Alexei [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Ohkubo, Takeru [Nuclear Engineering Research Laboratory, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Ueda, Toru [Nuclear Engineering Research Laboratory, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Muroya, Yusa [Nuclear Engineering Research Laboratory, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Katsumura, Yosuke [Nuclear Engineering Research Laboratory, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Iijima, Hokuto [Japan Atomic Energy Research Institute, 2-4 Shirane, Tokai, Naka, Ibaraki 319-1195 (Japan); Tomizawa, Hiromitsu [Japan Synchrotron Radiation Research InstituteI, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5198 (Japan); Kumagai, Noritaka [Japan Synchrotron Radiation Research InstituteI, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5198 (Japan)

    2005-12-15

    Femtosecond electron beams are novel tool for pump-probe analysis of condensed matter. Progress in developing femtosecond electron beams with the use of both conventional accelerators and laser-plasma accelerators is discussed. In conventional accelerators, the critical issue is timing jitter and drift of the linac-laser synchronization system. Sophisticated electronic devices are developed to reduce the jitter to 330 fs (rms); the precise control of temperature at several parts of the accelerator lessens the drift to 1 ps (rms). We also report on a full-optical X-ray and e-beam system based on the laser-plasma cathode by using a 12 TW 50 fs laser, which enables 40 MeV (at maximum), 40 fs (cal.), 100 pC and quasi-monochromatic single electron bunches. Since the synchronization is done by a passive optical beam-splitter, this system intrinsically has no jitter and drift. It could achieve tens of femtoseconds time-resolved analysis in the near future.

  1. Use of molecular beams for kinetic measurements of chemical reactions on solid surfaces

    Science.gov (United States)

    Zaera, Francisco

    2017-05-01

    In this review we survey the contributions that molecular beam experiments have provided to our understanding of the dynamics and kinetics of chemical interactions of gas molecules with solid surfaces. First, we describe the experimental details of the different instrumental setups and approaches available for the study of these systems under the ultrahigh vacuum conditions and with the model planar surfaces often used in modern surface-science experiments. Next, a discussion is provided of the most important fundamental aspects of the dynamics of chemical adsorption that have been elucidated with the help of molecular beam experiments, which include the development of potential energy surfaces, the determination of the different channels for energy exchange between the incoming molecules and the surface, the identification of adsorption precursor states, the understanding of dissociative chemisorption, the determination of the contributions of corrugation, steps, and other structural details of the surface to the adsorption process, the effect to molecular steering, the identification of avenues for assisting adsorption, and the molecular details associated with the kinetics of the uptake of adsorbates as a function of coverage. We follow with a summary of the work directed at the determination of kinetic parameters and mechanistic details of surface reactions associated with catalysis, mostly those promoted by late transition metals. This discussion we initiate with an overview of what has been learned about simple bimolecular reactions such as the oxidation of CO and H2 with O2 and the reaction of CO with NO, and continue with the review of the studies of more complex systems such as the oxidation of alcohols, the conversion of organic acids, the hydrogenation and isomerization of olefins, and the oxidative activation of alkanes under conditions of short contact times. Sections 6 and 7 of this review deal with the advances made in the use of molecular beams with

  2. Argon ion beam induced surface pattern formation on Si

    Energy Technology Data Exchange (ETDEWEB)

    Hofsäss, H.; Bobes, O.; Zhang, K. [2nd Institute of Physics, Faculty of Physics, University Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany)

    2016-01-21

    The development of self-organized surface patterns on Si due to noble gas ion irradiation has been studied extensively in the past. In particular, Ar ions are commonly used and the pattern formation was analyzed as function of ion incidence angle, ion fluence, and ion energies between 250 eV and 140 keV. Very few results exist for the energy regime between 1.5 keV and 10 keV and it appears that pattern formation is completely absent for these ion energies. In this work, we present experimental data on pattern formation for Ar ion irradiation between 1 keV and 10 keV and ion incidence angles between 50° and 75°. We confirm the absence of patterns at least for ion fluences up to 10{sup 18} ions/cm{sup 2}. Using the crater function formalism and Monte Carlo simulations, we calculate curvature coefficients of linear continuum models of pattern formation, taking into account contribution due to ion erosion and recoil redistribution. The calculations consider the recently introduced curvature dependence of the erosion crater function as well as the dynamic behavior of the thickness of the ion irradiated layer. Only when taking into account these additional contributions to the linear theory, our simulations clearly show that that pattern formation is strongly suppressed between about 1.5 keV and 10 keV, most pronounced at 3 keV. Furthermore, our simulations are now able to predict whether or not parallel oriented ripple patterns are formed, and in case of ripple formation the corresponding critical angles for the whole experimentally studied energies range between 250 eV and 140 keV.

  3. Improved laser damage threshold performance of calcium fluoride optical surfaces via Accelerated Neutral Atom Beam (ANAB) processing

    Science.gov (United States)

    Kirkpatrick, S.; Walsh, M.; Svrluga, R.; Thomas, M.

    2015-11-01

    Optics are not keeping up with the pace of laser advancements. The laser industry is rapidly increasing its power capabilities and reducing wavelengths which have exposed the optics as a weak link in lifetime failures for these advanced systems. Nanometer sized surface defects (scratches, pits, bumps and residual particles) on the surface of optics are a significant limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, magnesium fluoride, zinc sulfide, LBO and others presents a unique challenge for traditional polishing techniques. Exogenesis Corporation, using its new and proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and particle contamination leaving many material surfaces with roughness typically around one Angstrom. This surface defect mitigation via ANAB processing can be shown to increase performance properties of high intensity optical materials. This paper describes the ANAB technology and summarizes smoothing results for calcium fluoride laser windows. It further correlates laser damage threshold improvements with the smoothing produced by ANAB surface treatment. All ANAB processing was performed at Exogenesis Corporation using an nAccel100TM Accelerated Particle Beam processing tool. All surface measurement data for the paper was produced via AFM analysis on a Park Model XE70 AFM, and all laser damage testing was performed at Spica Technologies, Inc. Exogenesis Corporation's ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply mechanical forces associated with traditional polishing techniques. ANAB efficiently removes surface

  4. lon beam analysis of Brazilian coffee

    Energy Technology Data Exchange (ETDEWEB)

    Debastiani, R.; Santos, C.E.I. dos; Ramos, M.M.; Souza, V.S.; Yoneama, M.L.; Amaral, L.; Dias, J.F. [Universidade Federal do Rio Grande so Sul (UFRGS), Porto Alegre, RS (Brazil). Instituto de Fisica

    2013-07-01

    Full text: Coffee is one of the most popular and consumed beverages worldwide. Consumers can make the beverage from different types of coffee such as ground coffee, instant coffee or grinding roasted coffee beans. Each type of coffee leads to different characteristics in flavor and scent. The aim of this work is to perform an elemental analysis of ground coffee and roasted coffee beans. To that end, eight popular Brazilian ground coffee brands have been chosen to make a comparative study among brands. One of these brands was selected for a complete study of the beverage preparation process. This same brand offers packages of roasted coffee beans, which allowed the elemental comparison between ground coffee and roasted coffee beans. Roasted coffee beans were ground with a pestle and mortar. The beverage was prepared using a typical coffee pot. The spent and liquid coffees were submitted to a heat treatment and subsequently homogenized and pressed into pellets. The filters used in the coffee pot were analyzed as well. For micro-PIXE studies, coffee beans were cut in different parts for analysis. Samples of ground coffee and roasted coffee beans (grind) were analyzed by PIXE, while light elements like C, O and N were analyzed by RBS (Rutherford Backscattering Spectrometry). The roasted coffee beans were analyzed by micro-PIXE to check the elemental distribution in the beans. The elements found in powder coffee were Mg, AI, Si, P, S, CI, K, Ca, Ti, Mn, Fe, Cu, Zn and Rb. Potassium is the element with higher concentration, while Ti and Zn are trace elements. AI, Si and Ti showed the same concentration for all brands. Potassium and chlorine have high solubility, and about 80% of their concentration is transferred from the powder to the beverage during the infusion. Mg, P, CI, K, Mn, Fe, Zn and Rb showed significant variation between ground coffee and roasted coffee beans. The elemental maps show that potassium and phosphorus are correlated, and iron appears in particular

  5. Ion beam analysis of gold jewelry

    Science.gov (United States)

    Demortier, Guy

    1992-02-01

    PIXE milliprobe in a nonvacuum assembly has been proven to be a very rapid and accurate method for the elemental analysis of gold jewelry artefacts. Using protons whose energy is lower than 3 MeV, it is possible to obtain, in a few minutes, the actual composition (copper, iron, gold, silver, etc.) of narrow parts of artefacts, without any sampling, even at microscopic level. Most of the studies of our group in this field concern solders on these jewelry items. Narrow regions of gold artefacts have also been studied with a PIXE microprobe. They were then irradiated in vacuum. Nuclear reaction analyses induced by 2 MeV deuterons are also performed to identify the presence of light elements and, particularly O, N and S. Traces of these elements are of primary importance to characterize the origin of the ores used in various workmanships. Interferences of X-ray lines of Au with those of traces of Cu and Zn are solved using a method of selective excitation of X-rays of these elements. Analytical results have been interpreted in order to understand the workmanship of goldsmiths from the Antiquity. Fakes and repairs (or ornaments added to original artefacts) may also be identified. The ancient recipes are improved to give new soldering procedures at low temperature.

  6. Tailoring surface topographies of polymers by using ion beam: Recent advances and the potential applications in biomedical and tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Hasebe, Terumitsu, E-mail: teru_hasebe@sakura.med.toho-u.ac.jp [Department of Radiology, Toho University, Sakura Medical Center, 564-1 Shimoshizu, Sakura, Chiba 285-8741 (Japan); Center for Science of Environment, Resources and Energy, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan); Nagashima, So; Yoshimoto, Yukihiro; Hotta, Atsushi; Suzuki, Tetsuya [Center for Science of Environment, Resources and Energy, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan)

    2012-07-01

    Ion beam technique has recently been actively employed to create various patterns on the surface of polymers. In this paper, we highlight some of the recent advances in tailoring surface topographies of polymers by using ion beam and present a brief discussion on the potential applications in biomedical and tissue engineering.

  7. Application of nondiffracting Bessel beams for shaping of surface metal microstructures

    Science.gov (United States)

    Drampyan, Rafael; Leonov, Nikita; Vartanyan, Tigran

    2016-08-01

    A novel method of laser-controlled shaping of metal microstructures based on the processes of metal atoms adsorption on the surface of crystalline substrate and simultaneous control of photostimulated desorption of atoms by spatially modulated nondiffracting laser beam illumination is presented. The experiments were performed for sodium atoms deposition to the sapphire substrate, which was illuminated by Bessel beam at 532 nm wavelength and 2 W/cm2 intensity. Experiments showed that the optical pattern was well reproduced in the sodium deposits thus creating the annularly microstructured metal film with few tens nanometre thickness.

  8. X-ray fluorescence and ion beam analysis of iridescent Art Nouveau glass - authenticity and technology

    Science.gov (United States)

    Jembrih-Simbürger, D.; Neelmeijer, C.; Mäder, M.; Schreiner, M.

    2004-11-01

    EDXRF analysis with subsequent multivariate data analysis proves useful for the determination of the authenticity of iridescent glass artifacts. Thus, clusters of the glass groups investigated were formed which can be associated with the glass manufacturers. By means of ion beam analysis with the external proton beam the producing technology of iridescent glass objects of the Art Nouveau glass manufacturer Loetz/Austria with so-called Papillon pattern was characterised in a non-destructive way. Due to the simultaneous application of PIXE and RBS the glass structure including a sequence of glass layers covered with a SnO 2-layer of approximately 50 nm thickness on the surface could be described.

  9. X-ray fluorescence and ion beam analysis of iridescent Art Nouveau glass - authenticity and technology

    Energy Technology Data Exchange (ETDEWEB)

    Jembrih-Simbuerger, D. E-mail: d.jembrih@akbild.ac.at; Neelmeijer, C.; Maeder, M.; Schreiner, M

    2004-11-01

    EDXRF analysis with subsequent multivariate data analysis proves useful for the determination of the authenticity of iridescent glass artifacts. Thus, clusters of the glass groups investigated were formed which can be associated with the glass manufacturers. By means of ion beam analysis with the external proton beam the producing technology of iridescent glass objects of the Art Nouveau glass manufacturer Loetz/Austria with so-called Papillon pattern was characterised in a non-destructive way. Due to the simultaneous application of PIXE and RBS the glass structure including a sequence of glass layers covered with a SnO{sub 2}-layer of approximately 50 nm thickness on the surface could be described.

  10. Infrared beam-steering using acoustically modulated surface plasmons over a graphene monolayer

    KAUST Repository

    Chen, Paiyen

    2014-09-01

    We model and design a graphene-based infrared beamformer based on the concept of leaky-wave (fast traveling wave) antennas. The excitation of infrared surface plasmon polaritons (SPPs) over a \\'one-atom-thick\\' graphene monolayer is typically associated with intrinsically \\'slow light\\'. By modulating the graphene with elastic vibrations based on flexural waves, a dynamic diffraction grating can be formed on the graphene surface, converting propagating SPPs into fast surface waves, able to radiate directive infrared beams into the background medium. This scheme allows fast on-off switching of infrared emission and dynamic tuning of its radiation pattern, beam angle and frequency of operation, by simply varying the acoustic frequency that controls the effective grating period. We envision that this graphene beamformer may be integrated into reconfigurable transmitter/receiver modules, switches and detectors for THz and infrared wireless communication, sensing, imaging and actuation systems.

  11. Multichannel analysis of surface waves

    Science.gov (United States)

    Park, C.B.; Miller, R.D.; Xia, J.

    1999-01-01

    The frequency-dependent properties of Rayleigh-type surface waves can be utilized for imaging and characterizing the shallow subsurface. Most surface-wave analysis relies on the accurate calculation of phase velocities for the horizontally traveling fundamental-mode Rayleigh wave acquired by stepping out a pair of receivers at intervals based on calculated ground roll wavelengths. Interference by coherent source-generated noise inhibits the reliability of shear-wave velocities determined through inversion of the whole wave field. Among these nonplanar, nonfundamental-mode Rayleigh waves (noise) are body waves, scattered and nonsource-generated surface waves, and higher-mode surface waves. The degree to which each of these types of noise contaminates the dispersion curve and, ultimately, the inverted shear-wave velocity profile is dependent on frequency as well as distance from the source. Multichannel recording permits effective identification and isolation of noise according to distinctive trace-to-trace coherency in arrival time and amplitude. An added advantage is the speed and redundancy of the measurement process. Decomposition of a multichannel record into a time variable-frequency format, similar to an uncorrelated Vibroseis record, permits analysis and display of each frequency component in a unique and continuous format. Coherent noise contamination can then be examined and its effects appraised in both frequency and offset space. Separation of frequency components permits real-time maximization of the S/N ratio during acquisition and subsequent processing steps. Linear separation of each ground roll frequency component allows calculation of phase velocities by simply measuring the linear slope of each frequency component. Breaks in coherent surface-wave arrivals, observable on the decomposed record, can be compensated for during acquisition and processing. Multichannel recording permits single-measurement surveying of a broad depth range, high levels of

  12. Multiwave velocity analysis based on Gaussian beam prestack depth migration

    Institute of Scientific and Technical Information of China (English)

    Han Jian-Guang; Wang Yun; Han Ning; Xing Zhan-Tao; Lu Jun

    2014-01-01

    Prestack depth migration of multicomponent seismic data improves the imaging accuracy of subsurface complex geological structures. An accurate velocityfi eld is critical to accurate imaging. Gaussian beam migration was used to perform multicomponent migration velocity analysis of PP- and PS-waves. First, PP- and PS-wave Gaussian beam prestack depth migration algorithms that operate on common-offset gathers are presented to extract offset-domain common-image gathers of PP- and PS-waves. Second, based on the residual moveout equation, the migration velocity fields of P- and S-waves are updated. Depth matching is used to ensure that the depth of the target layers in the PP- and PS-wave migration profi les are consistent, and high-precision P- and S-wave velocities are obtained. Finally, synthetic andfi eld seismic data suggest that the method can be used effectively in multiwave migration velocity analysis.

  13. MIA analysis of FPGA BPMs and beam optics at APS

    Institute of Scientific and Technical Information of China (English)

    JI Da-Heng; WANG Chun-Xi; QIN Qing

    2012-01-01

    Model independent analysis,which was developed for high precision and fast beam dynamics analysis,is a promising diagnostic tool for modern accelerators.We implemented a series of methods to analyze the turn-by-turn BPM data.Green's functions corresponding to the local transfer matrix elements R12 or R34 are extracted from BPM data and fitted with the model lattice using least-square fitting.Here,we report experimental results obtained from analyzing the transverse motion of a beam in the storage ring at the Advanced Photon Source.BPM gains and uncoupled optics parameters are successfully determined.Quadrupole strengths are adjusted for fitting but can not be uniquely determined in general due to an insufficient number of BPMs.

  14. Fabrication of micro-prominences on PTFE surface using proton beam writing

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Akane, E-mail: ogawa.akane@jaea.go.jp [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan); Satoh, Takahiro; Koka, Masashi [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan); Kobayashi, Tomohiro [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 350-0198 (Japan); Kamiya, Tomihiro [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan)

    2013-07-01

    Polytetrafluoroethylene (PTFE) is a typical fluoropolymer and it has several desirable technological properties such as electrical insulation, solid lubrication etc. However, the conventional microstructuring methods have not been well applied to PTFE due to its chemical inertness. Some effective micromachining using synchrotron radiation or ion beam irradiation has been reported. In this study, we create micro-prominences by raising the original surface using proton beam writing (PBW) without chemical etching. A conical prominence was formed by spiral drawing from the center with a 3 MeV proton beam. The body was porous, and the bulk PTFE below the prominence changed to fragmented structures. With decreasing writing speed, the prominence became taller but the height peaked. The prominence gradually reduced in size after the speed reached the optimum value. We expect that these porous projections with high aspect ratio will be versatile in medical fields and microelectromechanical systems (MEMS) technology.

  15. Control of surface ripple amplitude in ion beam sputtered polycrystalline cobalt films

    Energy Technology Data Exchange (ETDEWEB)

    Colino, Jose M., E-mail: josemiguel.colino@uclm.es [Institute of Nanoscience, Nanotechnology and Molecular Materials, University of Castilla-La Mancha, Campus de la Fabrica de Armas, Toledo 45071 (Spain); Arranz, Miguel A. [Facultad de Ciencias Quimicas, University of Castilla-La Mancha, Ciudad Real 13071 (Spain)

    2011-02-15

    We have grown both polycrystalline and partially textured cobalt films by magnetron sputter deposition in the range of thickness (50-200 nm). Kinetic roughening of the growing film leads to a controlled rms surface roughness values (1-6 nm) increasing with the as-grown film thickness. Ion erosion of a low energy 1 keV Ar+ beam at glancing incidence (80{sup o}) on the cobalt film changes the surface morphology to a ripple pattern of nanometric wavelength. The wavelength evolution at relatively low fluency is strongly dependent on the initial surface topography (a wavelength selection mechanism hereby confirmed in polycrystalline rough surfaces and based on the shadowing instability). At sufficiently large fluency, the ripple wavelength steadily increases on a coarsening regime and does not recall the virgin surface morphology. Remarkably, the use of a rough virgin surface makes the ripple amplitude in the final pattern can be controllably increased without affecting the ripple wavelength.

  16. Error analysis in post linac to driver linac transport beam line of RAON

    Science.gov (United States)

    Kim, Chanmi; Kim, Eun-San

    2016-07-01

    We investigated the effects of magnet errors in the beam transport line connecting the post linac to the driver linac (P2DT) in the Rare Isotope Accelerator in Korea (RAON). The P2DT beam line is bent by 180-degree to send the radioactive Isotope Separation On-line (ISOL) beams accelerated in Linac-3 to Linac-2. This beam line transports beams with multi-charge state 132Sn45,46,47. The P2DT beam line includes 42 quadrupole, 4 dipole and 10 sextupole magnets. We evaluate the effects of errors on the trajectory of the beam by using the TRACK code, which includes the translational and the rotational errors of the quadrupole, dipole and sextupole magnets in the beam line. The purpose of this error analysis is to reduce the rate of beam loss in the P2DT beam line. The distorted beam trajectories can be corrected by using six correctors and seven monitors.

  17. Bone ingrowth potential of electron beam and selective laser melting produced trabecular-like implant surfaces with and without a biomimetic coating

    NARCIS (Netherlands)

    Biemond, J.E.; Hannink, G.J.; Verdonschot, N.J.; Buma, P.

    2013-01-01

    The bone ingrowth potential of trabecular-like implant surfaces produced by either selective laser melting (SLM) or electron beam melting (EBM), with or without a biomimetic calciumphosphate coating, was examined in goats. For histological analysis and histomorphometry of bone ingrowth depth and bon

  18. Bone ingrowth potential of electron beam and selective laser melting produced trabecular-like implant surfaces with and without a biomimetic coating

    NARCIS (Netherlands)

    Biemond, J.E.; Hannink, G.J.; Verdonschot, N.J.; Buma, P.

    2013-01-01

    The bone ingrowth potential of trabecular-like implant surfaces produced by either selective laser melting (SLM) or electron beam melting (EBM), with or without a biomimetic calciumphosphate coating, was examined in goats. For histological analysis and histomorphometry of bone ingrowth depth and

  19. Particle beam experiments for the investigation of plasma-surface interactions: application to magnetron sputtering and polymer treatment

    CERN Document Server

    Corbella, Carles; Kreiter, Oliver; Arcos, Teresa de los; Benedikt, Jan; von Keudell, Achim

    2013-01-01

    A beam experiment is presented to study heterogeneous reactions relevant to plasma-surface interactions. Atom and ion beams are focused onto the sample to expose it to quantified beams of oxygen, nitrogen, hydrogen, noble gas ions and metal vapor. The heterogeneous surface processes are monitored in-situ and in real time by means of a quartz crystal microbalance (QCM) and Fourier transform infrared spectroscopy (FTIR). Two examples illustrate the capabilities of the particle beam setup: oxidation and nitriding of aluminum as a model of target poisoning during reactive magnetron sputtering, and plasma treatment of polymers (PET, PP).

  20. A Novel Contactless Method for Characterization of Semiconductors: Surface Electron Beam Induced Voltage in Scanning Electron Microscopy

    Institute of Scientific and Technical Information of China (English)

    朱世秋; E.I.RAU; 杨富华; 郑厚植

    2002-01-01

    We present a novel contactless and nondestructive method called the surface electron beam induced voltage (SEBIV) method for characterizing semiconductor materials and devices. The SEBIV method is based on the detection of the surface potential induced by electron beams of scanning electron microscopy (SEM). The core part of the SEBIV detection set-up is a circular metal detector placed above the sample surface. The capacitance between the circular detector and whole surface of the sample is estimated to be about 0.64pf. It is large enough for the detection of the induced surface potential. The irradiation mode of electron beam (e-beam) influences the signal generation. When the e-beam irradiates on the surface of semiconductors continuously, a differential signal is obtained. The real distribution of surface potentials can be obtained when a pulsed e-beam with a fixed frequency is used for irradiation and a lock-in amplifier is employed for detection. The polarity of induced potential depends on the structure of potential barriers and surface states of samples. The contrast of SEBIV images in SEM changes with irradiation time and e-beam intensity.

  1. Automated analysis for detecting beams in laser wakefield simulations

    Energy Technology Data Exchange (ETDEWEB)

    Ushizima, Daniela M.; Rubel, Oliver; Prabhat, Mr.; Weber, Gunther H.; Bethel, E. Wes; Aragon, Cecilia R.; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Hamann, Bernd; Messmer, Peter; Hagen, Hans

    2008-07-03

    Laser wakefield particle accelerators have shown the potential to generate electric fields thousands of times higher than those of conventional accelerators. The resulting extremely short particle acceleration distance could yield a potential new compact source of energetic electrons and radiation, with wide applications from medicine to physics. Physicists investigate laser-plasma internal dynamics by running particle-in-cell simulations; however, this generates a large dataset that requires time-consuming, manual inspection by experts in order to detect key features such as beam formation. This paper describes a framework to automate the data analysis and classification of simulation data. First, we propose a new method to identify locations with high density of particles in the space-time domain, based on maximum extremum point detection on the particle distribution. We analyze high density electron regions using a lifetime diagram by organizing and pruning the maximum extrema as nodes in a minimum spanning tree. Second, we partition the multivariate data using fuzzy clustering to detect time steps in a experiment that may contain a high quality electron beam. Finally, we combine results from fuzzy clustering and bunch lifetime analysis to estimate spatially confined beams. We demonstrate our algorithms successfully on four different simulation datasets.

  2. Ion beam analysis in cultural heritage studies: Milestones and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Dran, Jean-Claude; Calligaro, Thomas [Centre for research and restoration of the museums of France, Palais du Louvre Paris (France)

    2013-07-18

    For three decades, ion beam analysis (IBA) in external mode was considered as the best choice for the characterisation of cultural heritage materials, as it combines excellent analytical performance and non-invasive character. However, in recent years, other analytical techniques arose as serious competitors, such as those based on synchrotron radiation (X-ray absorption, fluorescence or diffraction) or those using portable instruments (XRF, micro-Raman). It is shown that nevertheless IBA remains unmatched thanks to two unique features, namely the analysis of light elements and the high-resolution 3D chemical imaging.

  3. Ion-beam-induced nanodots formation from Au/Si thin films on quartz surface

    Energy Technology Data Exchange (ETDEWEB)

    Datta, D.P.; Siva, V.; Singh, A. [School of Physical Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Jatni - 752050, Odisha (India); Joshi, S.R. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, Odisha (India); Kanjilal, D. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Sahoo, P.K., E-mail: pratap.sahoo@niser.ac.in [School of Physical Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Jatni - 752050, Odisha (India)

    2016-07-15

    We report the synthesis of Si nanodots on quartz surface using ion irradiation. When a bi-layer of ultrathin Au and Si on quartz surface is irradiated by 500 keV Xe-ion beam, the bi-layer spontaneously transforms into nanodots at a fluence of 5 × 10{sup 14} ions cm{sup −2}. The spatial density and diameter of the nanodots are reduced with increase in applied ion fluence. The nanostructures exhibit photoluminescence in the visible range at room temperature where the intensity and wavelength depends upon ion fluence. The observed evolution seems to be correlated to ion beam mixing induced silicide formation at Au–Si interface.

  4. Analysis of shielding charged particle beams by thin conductors

    Directory of Open Access Journals (Sweden)

    Robert Gluckstern

    2001-02-01

    Full Text Available We present an analysis of shielding of electromagnetic fields excited by beams of charged particles surrounded by thin conducting layers or metal stripes inside an external structure of finite length. The ability of shielding by a layer thinner than the skin depth is explained and expressions for the impedance are derived. A previous result showing preferential penetration through the shielding layer at the resonant frequencies of the surrounding structure is verified and extended to include finite resistivity of the outer structure. Integration over the spectrum of the beam bunch shows that penetration is (nearly independent of the quality factors of the resonances. The transition of these results to those for a geometry of infinite length requires numerical evaluation.

  5. Model reduction and analysis of a vibrating beam microgyroscope

    KAUST Repository

    Ghommem, Mehdi

    2012-05-08

    The present work is concerned with the nonlinear dynamic analysis of a vibrating beam microgyroscope composed of a rotating cantilever beam with a tip mass at its end. The rigid mass is coupled to two orthogonal electrodes in the drive and sense directions, which are attached to the rotating base. The microbeam is driven by an AC voltage in the drive direction, which induces vibrations in the orthogonal sense direction due to rotation about the microbeam axis. The electrode placed in the sense direction is used to measure the induced motions and extract the underlying angular speed. A reduced-order model of the gyroscope is developed using the method of multiple scales and used to examine its dynamic behavior. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  6. Various categories of defects after surface alloying induced by high current pulsed electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Dian [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Tang, Guangze, E-mail: oaktang@hit.edu.cn [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Xinxin [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Gu, Le [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Sun, Mingren [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-10-01

    Highlights: • Four kinds of defects are found during surface alloying by high current electron beam. • Exploring the mechanism how these defects appear after irradiation. • Increasing pulsing cycles will help to get good surface quality. • Choosing proper energy density will increase surface quality. - Abstract: High current pulsed electron beam (HCPEB) is an attractive advanced materials processing method which could highly increase the mechanical properties and corrosion resistance. However, how to eliminate different kinds of defects during irradiation by HCPEB especially in condition of adding new elements is a challenging task. In the present research, the titanium and TaNb-TiW composite films was deposited on the carburizing steel (SAE9310 steel) by DC magnetron sputtering before irradiation. The process of surface alloying was induced by HCPEB with pulse duration of 2.5 μs and energy density ranging from 3 to 9 J/cm{sup 2}. Investigation of the microstructure indicated that there were several forms of defects after irradiation, such as surface unwetting, surface eruption, micro-cracks and layering. How the defects formed was explained by the results of electron microscopy and energy dispersive spectroscopy. The results also revealed that proper energy density (∼6 J/cm{sup 2}) and multi-number of irradiation (≥50 times) contributed to high quality of alloyed layers after irradiation.

  7. Coherent reflection of He atom beams from rough surfaces at near-grazing incidence

    OpenAIRE

    Zhao, B.; Schewe, C.; Meijer, G.; Schöllkopf, W.

    2010-01-01

    We report coherent reflection of thermal He atom beams from various microscopically rough surfaces at grazing incidence. For a sufficiently small normal component kz of the incident wave- vector of the atom the reflection probability is found to be a function of kz only. This behavior is explained by quantum-reflection at the attractive branch of the Casimir-van der Waals interaction potential. For larger values of kz the overall reflection probability decreases rapidly and is found to also d...

  8. Experimental analysis of the steady-state behaviour of beam systems with discontinuous support

    NARCIS (Netherlands)

    Vorst, E.L.B. van de; Campen, D.H. van; Kraker, A. de; Fey, R.H.B.

    1996-01-01

    This paper deals with the experimental analysis of the long-term behaviour of periodically excited linear beams supported by a one-sided spring or an elastic stop. Numerical analysis of the beams showed subharmonic, quasi-periodic and chaotic behaviour. Furthermore, in the beam system with the one-s

  9. Beam lifetime measurement and analysis in Indus-2 electron storage ring

    Indian Academy of Sciences (India)

    Pradeep Kumar; A D Ghodke; Gurnam Singh

    2013-05-01

    In this paper, the beam lifetime measurement and its theoretical analysis are presented using measured vacuum pressure and applied radio frequency (RF) cavity voltage in Indus-2 electron storage ring at 2 GeV beam energy. Experimental studies of the effect of RF cavity voltage and bunched beam filling pattern on beam lifetime are also presented. An equation of stable beam current decay is evolved and this equation closely follows the observed beam current decay pattern. It shows that the beam is stable and the beam current decay is due to the beam–residual gas interaction (vacuum lifetime) and electron–electron interaction within a bunch (Touschek lifetime). The estimated vacuum, Touschek and total beam lifetimes from analytical formulations are also compared with the measured beam lifetime.

  10. Hydrogen effect on zirconium alloy surface treated by pulsed electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Pushilina, N.S.; Lider, A.M. [Department of General Physics, Institute of Physics and Technology, National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Kudiiarov, V.N., E-mail: viktor.kudiiarov@gmail.com [Department of General Physics, Institute of Physics and Technology, National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Chernov, I.P. [Department of General Physics, Institute of Physics and Technology, National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Ivanova, S.V. [National Research Nuclear University “MIFI”, Kashirskoye shosse 31, Moscow 115409 (Russian Federation)

    2015-01-15

    Influence of modification by pulsed electron beam (PEB) and hydrogen adsorption in zirconium alloys have been investigated. Treatment of Zr–1Nb alloy by high-current PEB allows for a decrease in the amount of hydrogen absorbed by the samples during the hydrogenation process from gas atmosphere in the temperature range of (350–550 °S). The effect of the PEB surface treatment on the hydrogen adsorption connected with the formation of a protective oxide film after PEB irradiation and also by the formation of a specific hardening structure under the action of irradiation at temperatures exceeding the melting temperature from the subsequent high-speed surface cooling.

  11. Electron beam heating effects during environmental scanning electron microscopy imaging of water condensation on superhydrophobic surfaces

    Science.gov (United States)

    Rykaczewski, K.; Scott, J. H. J.; Fedorov, A. G.

    2011-02-01

    Superhydrophobic surfaces (SHSs) show promise as promoters of dropwise condensation. Droplets with diameters below ˜10 μm account for the majority of the heat transferred during dropwise condensation but their growth dynamics on SHS have not been systematically studied. Due to the complex topography of the surface environmental scanning electron microscopy is the preferred method for observing the growth dynamics of droplets in this size regime. By studying electron beam heating effects on condensed water droplets we establish a magnification limit below which the heating effects are negligible and use this insight to study the mechanism of individual drop growth.

  12. Waveform synthesis of surface waves in a laterally heterogeneous earth by the Gaussian beam method

    Science.gov (United States)

    Yomogida, K.; Aki, K.

    1985-01-01

    The present investigation is concerned with an application of the Gaussian beam method to surface waves in the laterally heterogeneous earth. The employed method has been developed for ray tracing and synthesizing seismograms of surface waves in cases involving the laterally heterogeneous earth. The procedure is based on formulations derived by Yomogida (1985). Vertical structure of the wave field is represented by the eigenfunctions of normal mode theory, while lateral variation is expressed by the parabolic equation as in two-dimensional acoustic waves or elastic body waves. It is demonstrated that a large-amplitude change can result from a slight perturbation in the phase velocity model.

  13. Surface morphological evolution and nanoneedle formation of 18Cr-ODS steel by focused ion beam bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Ran, Guang, E-mail: gran@xmu.edu.cn [College of Energy, Xiamen University, Xiamen City, Fujian Province 361102 (China); Chen, Nanjun; Qiang, Rui [College of Energy, Xiamen University, Xiamen City, Fujian Province 361102 (China); Wang, Lumin [College of Energy, Xiamen University, Xiamen City, Fujian Province 361102 (China); Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Li, Ning [College of Energy, Xiamen University, Xiamen City, Fujian Province 361102 (China); Lian, Jie, E-mail: lianj@rpi.edu [Department of Mechanical, Aerospace & Nuclear Engineering, Rensselaer Polytechnic Institute, NY (United States)

    2015-08-01

    Highlights: • Morphological evolution of the 18Cr-ODS was studied under intense ion radiation. • The initial surface morphology of the steel significantly affects the nanoneedle formation, and the microstructure of the nanoneedle was characterized by TEM. • The formation mechanism of nano-needle structure of the 18Cr-ODS was discussed. • Surface defects enhance kinetics of surface roughening and pattern formation. - Abstract: Morphological evolution upon intense energetic particle–matter interactions is of fundamental importance for materials utilized in extreme radiation environment, and controlling surface morphology by radiation also provides a new pathway for exploring non-equilibrium process at surface. In this work, surface morphology and microstructural evolution upon low energy ion irradiation of 18Cr-ODS, a candidate structural material for cladding and first wall of future fission and fusion reactors, were investigated by in situ focused Ga{sup +} ion beam/scanning electron microscopy and ex situ transmission electron microscopy. A surface roughening through pore formation, coalescence and eventually nanoneedle formation was induced on 18Cr-ODS steel surface. Cross-section microstructure analysis indicates that the formation of nanoneedle was not a result of grain recrystallization or chemical composition change. Pre-irradiated materials by He{sup +} and Fe{sup +} ions displays enhanced kinetics for surface morphological evolution and lower fluences of focused Ga{sup +} are required for the nanoneedle formation. These results suggest that the surface roughening and morphological evolution of 18Cr-ODS under low energy ion irradiation is an interplay between a curvature-dependent sputtering and defect accumulation near the surface.

  14. Ion beam analysis techniques applied to large scale pollution studies

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, D.D.; Bailey, G.; Martin, J.; Garton, D.; Noorman, H.; Stelcer, E.; Johnson, P. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1993-12-31

    Ion Beam Analysis (IBA) techniques are ideally suited to analyse the thousands of filter papers a year that may originate from a large scale aerosol sampling network. They are fast multi-elemental and, for the most part, non-destructive so other analytical methods such as neutron activation and ion chromatography can be performed afterwards. ANSTO in collaboration with the NSW EPA, Pacific Power and the Universities of NSW and Macquarie has established a large area fine aerosol sampling network covering nearly 80,000 square kilometres of NSW with 25 fine particle samplers. This network known as ASP was funded by the Energy Research and Development Corporation (ERDC) and commenced sampling on 1 July 1991. The cyclone sampler at each site has a 2.5 {mu}m particle diameter cut off and runs for 24 hours every Sunday and Wednesday using one Gillman 25mm diameter stretched Teflon filter for each day. These filters are ideal targets for ion beam analysis work. Currently ANSTO receives 300 filters per month from this network for analysis using its accelerator based ion beam techniques on the 3 MV Van de Graaff accelerator. One week a month of accelerator time is dedicated to this analysis. Four simultaneous accelerator based IBA techniques are used at ANSTO, to analyse for the following 24 elements: H, C, N, O, F, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Ni, Co, Zn, Br and Pb. The IBA techniques were proved invaluable in identifying sources of fine particles and their spatial and seasonal variations accross the large area sampled by the ASP network. 3 figs.

  15. AN ELASTIC STRESS ANALYSIS FOR A POLYMER MATRIX COMPOSITE CANTILEVER BEAM SUBJECTED TO A SINGLE TRANSVERSE FORCE

    Directory of Open Access Journals (Sweden)

    Ayla TEKİN

    2004-03-01

    Full Text Available In this study, elasto-plastic stress analysis is carried out in a polymer matrix composite cantilever beam of arbitrary fiber orientation subjected to a single transverse force applied to the free end by using the anisotropic elasticity theory. The residual stress component of ?x and yield points are determined for 0°, 30°, 45°, 60° and 90° fiber orientation angles. The yielding begins for 0° and 90° fiber orientation angles at the upper and lower surfaces of the beam at the same distances from the free end. It is seen that the yielding begins for 30°, 45° and 60° fiber orientation angles at the upper surface of the beam. The intensity of the residual stress component of ?x is maximum at the upper and lower surfaces of the beam. In this study, the residual stress component of ?x obtained for the polymer matrix composite thermoplastic cantilever beam reinforced by reinforced unidirectional fibers is compared with that of the thermoplastic cantilever beam reinforced by woven Cr-Ni steel fibers.

  16. Beam dynamics analysis in pulse compression using electron beam compact simulator for Heavy Ion Fusion

    Directory of Open Access Journals (Sweden)

    Kikuchi Takashi

    2013-11-01

    Full Text Available In a final stage of an accelerator system for heavy ion inertial fusion (HIF, pulse shaping and beam current increase by bunch compression are required for effective pellet implosion. A compact simulator with an electron beam was constructed to understand the beam dynamics. In this study, we investigate theoretically and numerically the beam dynamics for the extreme bunch compression in the final stage of HIF accelerator complex. The theoretical and numerical results implied that the compact experimental device simulates the beam dynamics around the stagnation point for initial low temperature condition.

  17. MODAL TEST AND ANALYSIS OF CANTILEVER BEAM WITH TIP MASS

    Institute of Scientific and Technical Information of China (English)

    肖世富; 杜强; 陈滨; 刘才山; 向荣山; 周为华; 徐友钜; 徐有刚

    2002-01-01

    The phenomenon of dynamic stiffening is a research field of general interest for flexible multi-body systems. In fact, there are not only dynamic stiffening but also dynamic softening phenomenon in the flexible multi-body systems. In this paper, a non-linear dynamic model and its linearization characteristic equations of a cantilever beam with tip mass in the centrifugal field are established by adopting the general Hamilton Variational Principle. Then, the problems of the dynamic stiffening and the dynamic softening are studied by using numerical simulations. Meanwhile,the modal test is carried out on our centrifuge. The numerical results show that the system stiffness will be strengthened when the centrifugal tension force acts on the beam (i.e. the dynamic stiffening). However, the system stiffness will be weakened when the centrifugal compression force acts on the beam (i.e. the dynamic softening).Furthermore, the equilibrium position of the system will lose its stability when the inertial force reaches a critical value. Through theoretical analysis, we find that this phenomenon comes from the effect of dynamic softening resulting from the centrifugal compression force. Our test results verify the above conclusions and confirm that both dynamic stiffening and softening phenomena exist in flexible multi-body systems.

  18. PERFORMANCE ANALYSIS OF AZIMUTH ELECTRONIC BEAM STEERING MODE SPACEBORNE SAR

    Institute of Scientific and Technical Information of China (English)

    Han Xiaodong; Xu Wei; Han Xiaolei

    2013-01-01

    Pointing angle and pattern of the antenna can be changed swiftly to actualize the azimuth beam scanning by using electronic beam steering,which makes the Synthetic Aperture Radar (SAR)system more flexible and achieve a high resolution or cover a long strip within short time span.When the pointing angle is steered away from boresight,some aberrations may appear on the antenna pattern,e.g.,the grating lobe appears,the main lobe gain decrease,and antenna pattern broadens,e.g.,the aberrations result in the worsening of system performance,and complicate the corresponding performance analysis method.Conventional computation methods of performance parameters do not account for the rapid change of the antenna pattern.It introduces remarkable errors when the scanning angle is large.In this paper,a method of calculating performance parameters is proposed for the beam steering mode,which achieves the parameters by the energy accumulation in time domain.Actually,the proposed method simulates the working process of SAR and obtains accurate performance parameters.Furthermore,we analyze the effects of the grating lobe on the Azimuth Ambiguity to Signal Ratio (AASR),and present the generic Pulse Repetition Frequency (PRF) choosing principle which can also prevent the ambiguous area from weighting by the grating lobe.Finally,the effect of the antenna configuration on the performance parameters is analyzed by a system example.

  19. Surface dose variations in 6 and 10 MV flattened and flattening filter-free (FFF) photon beams.

    Science.gov (United States)

    Cashmore, Jason

    2016-01-01

    As the use of linear accelerators operating in flattening filter-free (FFF) modes becomes more widespread, it is important to have an understanding of the surface doses delivered to patients with these beams. Flattening filter removal alters the beam quality and relative contributions of low-energy X-rays and contamination electrons in the beam. Having dosimetric data to describe the surface dose and buildup regions under a range of conditions for FFF beams is important if clinical decisions are to be made. An Elekta Synergy linac with standard MLCi head has been commissioned to run at 6 MV and 10 MV running with the flattening filter in or out. In this linac the 6 MV FFF beam has been energy-matched to the clinical beam on the central axis (D10). The 10 MV beam energy has not been adjusted. The flattening filter in both cases is replaced by a thin (2 mm) stainless steel plate. A thin window parallel plate chamber has been used to measure a comprehensive set of surface dose data in these beams for variations in field size and SSD, and for the presence of attenuators (wedge, shadow tray, and treatment couch). Surface doses are generally higher in FFF beams for small field sizes and lower for large field sizes with a crossover at 10 × 10 cm2 at 6 MV and 25 × 25 cm2 at 10 MV. This trend is also seen in the presence of the wedge, shadow tray, and treatment couch. Only small differences (free beams show far less variation with field size than conventional beams. By removing the flattening filter, a source of contamination electrons is exchanged for a source of low-energy photons (as these are no longer attenuated). In practice these two components almost balance out. No significant effects on surface dose are expected by the introduction of FFF delivery.

  20. Surface treatment of 0.20% C carbon steel by high-current pulsed electron beam

    Institute of Scientific and Technical Information of China (English)

    XU Guo-cheng; FU Shi-you; GUAN Qing-feng

    2006-01-01

    A high-current pulsed electron beam(HCPEB) generated on the system of Nadezhda-2 was applied to improve the microstructure and performance of 0.20% C low carbon steel. Surface layers of the samples bombarded by explosive electron beam at different pulses was observed by using electron microscopy. The physical model of the thermal-stress process and related modification mechanism as a result of HCPEB irradiation was also investigated. After HCPEB post treatments, obvious changes in microstructure and significant hardening occur in the depth of 200-250 μm from the surface after HCPEB irradiation. Rapid heating and subsequent rapid solidification induce heavy plastic deformation, which results in that the laminated structure of pearlite is substituted by dispersive rounded-like cementites in the near-surface. The effect of HCPEB treatment can reach more than 500 m depth from the surface. The original crystalline structure is changed to a different degree that grows with the numbers of bombardment, and in the surface layer amorphous states and nanocrystaline structures consisting of grains of γ-phase and cementite are found. The violent stress induced by HCPEB irradiation is the origin of the nanostructured and amorphous structure formation.

  1. The Surface Roughness of (433) Eros as Measured by Thermal-Infrared Beaming

    CERN Document Server

    Rozitis, Ben

    2016-01-01

    In planetary science, surface roughness is regarded to be a measure of surface irregularity at small spatial scales, and causes the thermal-infrared beaming effect (i.e. re-radiation of absorbed sunlight back towards to the Sun). Typically, surface roughness exhibits a degeneracy with thermal inertia when thermophysical models are fitted to disc-integrated thermal-infrared observations of asteroids because of this effect. In this work, it is demonstrated how surface roughness can be constrained for near-Earth asteroid (433) Eros (i.e. the target of NASA's NEAR Shoemaker mission) when using the Advanced Thermophysical Model with thermal-infrared observations taken during an "almost pole-on" illumination and viewing geometry. It is found that the surface roughness of (433) Eros is characterised by an RMS slope of 38 $\\pm$ 8{\\deg} at the 0.5-cm spatial scale associated with its thermal-infrared beaming effect. This is slightly greater than the RMS slope of 25 $\\pm$ 5{\\deg} implied by the NEAR Shoemaker laser ran...

  2. Internal Energy Dependence of Molecular Condensation Coefficients Determined from Molecular Beam Surface Scattering Experiments

    Science.gov (United States)

    Sibener, S. J.; Lee, Y. T.

    1978-05-01

    An experiment was performed which confirms the existence of an internal mode dependence of molecular sticking probabilities for collisions of molecules with a cold surface. The scattering of a velocity selected effusive beam of CCl{sub 4} from a 90 K CC1{sub 4} ice surface has been studied at five translational velocities and for two different internal temperatures. At a surface temperature of 90 K (approx. 99% sticking probability) a four fold increase in reflected intensity was observed for the internally excited (560 K) CC1{sub 4} relative to the room temperature (298 K) CC1{sub 4} at a translational velocity of 2.5 X 10{sup 4} cm/sec. For a surface temperature of 90 K all angular distributions were found to peak 15{sup 0} superspecularly independent of incident velocity.

  3. DISCUSSION ON DEFECTS DISTRIBUTION NEAR THE STEEL SURFACE IRRADIATED BY INTENSE PULSED ION BEAM

    Institute of Scientific and Technical Information of China (English)

    X.Y.Le; S.Yan; W.J.Zhao; B.X.Han; W.Xiang

    2002-01-01

    The surface defect distribution in stainless steel irradiated with intense pulsed ion beam(IPIB) of current density above 60A/cm2 and acceleration voltage 300-500keV wasdiscussed and analyzed. The defects near the surface of stainless steel were generatedin two ways: (1) generated by the bombardment of energetic ions and (2) induced bythe high level stress near the surface. Thus the temperature and stress distributionsnear the steel surface were calculated by means of our STEIPIB code, which treatedwith the thermal-dynamical process in the target irradiated by the IPIB. Based onthese distributions, the generations and movements of these defects were discussedand compared with the experiment results.

  4. Wettability modification of human tooth surface by water and UV and electron-beam radiation

    Energy Technology Data Exchange (ETDEWEB)

    Tiznado-Orozco, Gaby E., E-mail: gab0409@gmail.com [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Unidad Académica de Odontología, Universidad Autónoma de Nayarit, Edificio E7, Ciudad de la Cultura “Amado Nervo”, C.P. 63190 Tepic, Nayarit (Mexico); Reyes-Gasga, José, E-mail: jreyes@fisica.unam.mx [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Instituto de Física, UNAM, Circuito de la Investigación s/n, Ciudad Universitaria, 04510 Coyoacan, México, D.F. (Mexico); Elefterie, Florina, E-mail: elefterie_florina@yahoo.com [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Beyens, Christophe, E-mail: christophe.beyens@ed.univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Maschke, Ulrich, E-mail: Ulrich.Maschke@univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Brès, Etienne F., E-mail: etienne.bres@univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France)

    2015-12-01

    The wettability of the human tooth enamel and dentin was analyzed by measuring the contact angles of a drop of distilled water deposited on the surface. The samples were cut along the transverse and longitudinal directions, and their surfaces were subjected to metallographic mirror-finish polishing. Some samples were also acid etched until their microstructure became exposed. Wettability measurements of the samples were done in dry and wet conditions and after ultraviolet (UV) and electron beam (EB) irradiations. The results indicate that water by itself was able to increase the hydrophobicity of these materials. The UV irradiation momentarily reduced the contact angle values, but they recovered after a short time. EB irradiation raised the contact angle and maintained it for a long time. Both enamel and dentin surfaces showed a wide range of contact angles, from approximately 10° (hydrophilic) to 90° (hydrophobic), although the contact angle showed more variability on enamel than on dentin surfaces. Whether the sample's surface had been polished or etched did not influence the contact angle value in wet conditions. - Highlights: • Human tooth surface wettability changes in dry/wet and UV/EB radiation conditions. • More variability in contact angle is observed on enamel than on dentin surfaces. • Water by itself increases the hydrophobicity of the human tooth surface. • UV irradiation reduces momentarily the human tooth surface hydrophobicity. • EB irradiation increases and maintains the hydrophobicity for a long time.

  5. Biomechanical and histological evaluation of roughened surface titanium screws fabricated by electron beam melting.

    Directory of Open Access Journals (Sweden)

    Jun Yang

    Full Text Available BACKGROUND: Various fabrication methods are used to improve the stability and osseointegration of screws within the host bone. The aim of this study was to investigate whether roughened surface titanium screws fabricated by electron beam melting can provide better stability and osseointegration as compared with smooth titanium screws in sheep cervical vertebrae. METHODS: Roughened surface titanium screws, fabricated by electron beam melting, and conventional smooth surface titanium screws were implanted into sheep for 6 or 12 weeks (groups A and B, respectively. Bone ingrowth and implant stability were assessed with three-dimensional imaging and reconstruction, as well as histological and biomechanical tests. RESULTS: No screws in either group showed signs of loosening. Fibrous tissue formation could be seen around the screws at 6 weeks, which was replaced with bone at 12 weeks. Bone volume/total volume, bone surface area/bone volume, and the trabecular number were significantly higher for a define region of interest surrounding the roughened screws than that surrounding the smooth screws at 12 weeks. Indeed, for roughened screws, trabecular number was significantly higher at 12 weeks than at 6 weeks. On mechanical testing, the maximum pullout strength was significantly higher at 12 weeks than at 6 weeks, as expected; however, no significant differences were found between smooth and roughened screws at either time point. The maximum torque to extract the roughened screws was higher than that required for the smooth screws. CONCLUSIONS: Electron beam melting is a simple and effective method for producing a roughened surface on titanium screws. After 12 weeks, roughened titanium screws demonstrated a high degree of osseointegration and increased torsional resistance to extraction over smooth titanium screws.

  6. Biomechanical and histological evaluation of roughened surface titanium screws fabricated by electron beam melting.

    Science.gov (United States)

    Yang, Jun; Cai, Hong; Lv, Jia; Zhang, Ke; Leng, Huijie; Wang, Zhiguo; Liu, Zhongjun

    2014-01-01

    Various fabrication methods are used to improve the stability and osseointegration of screws within the host bone. The aim of this study was to investigate whether roughened surface titanium screws fabricated by electron beam melting can provide better stability and osseointegration as compared with smooth titanium screws in sheep cervical vertebrae. Roughened surface titanium screws, fabricated by electron beam melting, and conventional smooth surface titanium screws were implanted into sheep for 6 or 12 weeks (groups A and B, respectively). Bone ingrowth and implant stability were assessed with three-dimensional imaging and reconstruction, as well as histological and biomechanical tests. No screws in either group showed signs of loosening. Fibrous tissue formation could be seen around the screws at 6 weeks, which was replaced with bone at 12 weeks. Bone volume/total volume, bone surface area/bone volume, and the trabecular number were significantly higher for a define region of interest surrounding the roughened screws than that surrounding the smooth screws at 12 weeks. Indeed, for roughened screws, trabecular number was significantly higher at 12 weeks than at 6 weeks. On mechanical testing, the maximum pullout strength was significantly higher at 12 weeks than at 6 weeks, as expected; however, no significant differences were found between smooth and roughened screws at either time point. The maximum torque to extract the roughened screws was higher than that required for the smooth screws. Electron beam melting is a simple and effective method for producing a roughened surface on titanium screws. After 12 weeks, roughened titanium screws demonstrated a high degree of osseointegration and increased torsional resistance to extraction over smooth titanium screws.

  7. Nonlinear Dynamical analysis of an AFM tapping mode microcantilever beam

    Directory of Open Access Journals (Sweden)

    Choura S.

    2012-07-01

    Full Text Available We focus in this paper on the modeling and dynamical analysis of a tapping mode atomic force microscopy (AFM microcantilever beam. This latter is subjected to a harmonic excitation of its base displacement and to Van der Waals and DMT contact forces at its free end. For AFM design purposes, we derive a mathematical model for accurate description of the AFM microbeam dynamics. We solve the resulting equations of motions and associated boundary conditions using the Galerkin method. We find that using one-mode approximation in tapping mode operating in the neighborhood of the contact region one-mode approximation may lead to erroneous results.

  8. 22nd International Conference on Ion Beam Analysis

    Science.gov (United States)

    Radović, Iva Bogdanović; Jakšić, Milko; Fazinić, Stjepko

    2016-03-01

    This special issue of Nuclear Instruments and Methods in Physics Research B contains the proceedings of the 22nd International Conference on Ion Beam Analysis (IBA 2015). The conference was held in Grand Hotel 4 Opatijska Cvijeta in Opatija, Croatia, between 14th and 19th June 2015. Opatija, one of the Croatia's most famous touristic destinations, often called the pearl of the Adriatic, is celebrating this year 170 years of tourism. During the past, kings and emperors, writers, philosophers, poets and composers, but also scientists, used to stay in the town mainly built at the turn of the 20th century.

  9. Computer simulation of ion beam analysis of laterally inhomogeneous materials

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, M.

    2016-03-15

    The program STRUCTNRA for the simulation of ion beam analysis charged particle spectra from arbitrary two-dimensional distributions of materials is described. The code is validated by comparison to experimental backscattering data from a silicon grating on tantalum at different orientations and incident angles. Simulated spectra for several types of rough thin layers and a chessboard-like arrangement of materials as example for a multi-phase agglomerate material are presented. Ambiguities between back-scattering spectra from two-dimensional and one-dimensional sample structures are discussed.

  10. Static and Dynamic Experimental Analysis of the Galloping Stability of Porous H-Section Beams

    Directory of Open Access Journals (Sweden)

    F. Gandia

    2014-01-01

    Full Text Available The phenomenon of self-induced vibrations of prismatic beams in a cross-flow has been studied for decades, but it is still of great interest due to their important effects in many different industrial applications. This paper presents the experimental study developed on a prismatic beam with H-section. The aim of this analysis is to add some additional insight into the behaviour of the flow around this type of bodies, in order to reduce galloping and even to avoid it. The influence of some relevant geometrical parameters that define the H-section on the translational galloping behaviour of these beams has been analysed. Wind loads coefficients have been measured through static wind tunnel tests and the Den Hartog criterion applied to elucidate the influence of geometrical parameters on the galloping properties of the bodies under consideration. These results have been completed with surface pressure distribution measurements and, besides, dynamic tests have been also performed to verify the static criterion. Finally, the morphology of the flow past the tested bodies has been visualised by using smoke visualization techniques. Since the rectangular section beam is a limiting case of the H-section configuration, the results here obtained are compared with the ones published in the literature concerning rectangular configurations; the agreement is satisfactory.

  11. Modeling and analysis of smart piezoelectric beams using simple higher order shear deformation theory

    Science.gov (United States)

    Adnan Elshafei, M.; Alraiess, Fuzy

    2013-03-01

    In the current work, a finite element formulation is developed for modeling and analysis of isotropic as well as orthotropic composite beams with distributed piezoelectric actuators subjected to both mechanical and electrical loads. The proposed model is developed based on a simple higher order shear deformation theory where the displacement field equations in the model account for a parabolic distribution of the shear strain and the nonlinearity of in-plane displacements across the thickness and subsequently the shear correction factor is not involved. The virtual displacement method is used to formulate the equations of motion of the structure system. The model is valid for both segmented and continuous piezoelectric elements, which can be either surface bonded or embedded in the laminated beams. A two-node element with four mechanical degrees of freedom in addition to one electrical degree of freedom for each node is used in the finite element formulation. The electric potential is considered as a function of the thickness and the length of the beam element. A MATLAB code is developed to compute the static deformation and free vibration parameters of the beams with distributed piezoelectric actuators. The obtained results from the proposed model are compared with the available analytical results and the finite element results of other researchers.

  12. Effects of topographical surface modifications of electron beam melted Ti-6Al-4V titanium on human fetal osteoblasts.

    Science.gov (United States)

    Ponader, Sabine; Vairaktaris, Eleftherios; Heinl, Peter; Wilmowsky, Cornelius V; Rottmair, Andreas; Körner, Carolin; Singer, Robert F; Holst, Stefan; Schlegel, Karl A; Neukam, Friedrich W; Nkenke, Emeka

    2008-03-15

    The aim of the study was to assess the suitability of different Ti-6Al-4V surfaces produced by the electron beam melting (EBM) process as matrices for attachment, proliferation, and differentiation of human fetal osteoblasts (hFOB 1.19). Human osteoblasts were cultured in vitro on smooth and rough-textured Ti-6Al-4V alloy disks. By means of cell number and vitality and SEM micrographs cell attachment and proliferation were observed. The differentiation rate was examined by using quantitative real-time PCR analysis for the gene expression of alkaline phosphatase (ALP), type I collagen (Coll-I), bone sialoprotein (BSP) and osteocalcin (OC). After 3 days of incubation there was a significant higher vitality (p /= 56.9 microm) reduced proliferation of hFOB cells. Surface characteristics of titanium can easily be changed by EBM in order to further improve proliferation. (c) 2007 Wiley Periodicals, Inc.

  13. The beam delivery modeling and error sources analysis of beam stabilization system for lithography

    Science.gov (United States)

    Wang, Jun; Huang, Lihua; Hou, Liying; He, Guojun; Ren, Bingqiang; Zeng, Aijun; Huang, Huijie

    2013-12-01

    Beam stabilization system is one of the most important units for lithography, which can accomplish displacement and pointing detection and control and includes beam measurement unit(BMU) and beam steering unit(BSU). Our group has set up a beam stabilization system and verified preliminarily beam stabilization algorithm of precise control beam position and angle. In the article, we establish beam delivery mathematic model and analyze the system inherent error. This shows that the reason why image rotation effect arises at the output plane of beam stabilization is the fast steering mirror (FSM) rotation of BSU in the process of beam stabilization. Two FSMs rotation around 45o axis of FSM make the most contribution to image rotation which rotates 1.414 mrad as two FSMs rotation angle difference changes 1 mrad. It is found that error sources include three key points: FSM accuracy; measurement noise and beam translation by passing through of beam splitters changing as the ambient temperature changing. FSM accuracy leads to the maximum 13.2μm displacement error and 24.49μrad angle error. Measurement inaccuracy as a result of 5μm measurement noise results in the maximum 0.126mm displacement error and 57.2μrad angle error. Beam translation errors can be negligible if temperature is unchanged. We have achieved beam stability of about 15.5μrad for angle and 28μm for displacement (both 1σ) after correcting 2mm initial displacement deviation and 5mrad initial angle deviation with regard to the system rebuilt due to practical requirements.

  14. Contamination analysis of radioactive samples in focused ion beam instruments.

    Science.gov (United States)

    Evelan, Audrey Ruth; Brey, Richard R

    2013-02-01

    The use of Focused Ion Beam (FIB) instrument's to analyze and prepare samples that are radioactive requires attentiveness to the materials that are dislodged and free inside the chamber. Radioactive sputtered material must be understood even when observed at trace concentrations. Measurements using liquid scintillation counting and high purity germanium detectors were used to evaluate contamination on accessible surfaces inside a focused ion beam chamber that was used in the preparation of samples that were radioactive. The maximum removable contamination found was 0.27 0.4 Bq cm(-2), on the focused ion beam wall with 0.24 0.019 Bq cm(-2) on the door. Although these magnitudes of removable contamination are inconsequential for activation products, these same magnitudes of actinides, for example 239Pu, would represent 3.2% of an Annual Limit of Intake. This might be considered significant if one examines the relatively infrequent use of this device for the preparation of radioactive samples. Predicted activities of sputtered material were found using the software Transport of Ions in Matter, estimating that 0.003% of a radioactive samples activity is released into the FIB chamber. A used secondary electron detector's activity was measured to be 383.7 8.1 Bq. Preferential build-up of sputtered materials due to temperature or static charge gradients was considered. No temperature gradients were observed. Static charge gradients were measured inside the chamber varying between 0.057% below the mean to 34% higher than the mean. However, the magnitudes of contamination measured did not correlate to static charge gradients. Deposition in the chamber appears to have no mechanical cause but rather is sporadic however, measureable. Experience to date has been limited to samples of low activity; nevertheless, contamination inside the chamber was observed. Users should anticipate higher levels of readily dispersible radioactive contamination within the FIB as sample activity

  15. Fractography of Fatigue Fracture Surface in Silumin Subjected to Electron-Beam Processing

    Science.gov (United States)

    Konovalov, S. V.; Aksenova, K. V.; Gromov, V. E.; Ivanov, Yu F.; Semina, O. A.

    2016-08-01

    The surface modification of the eutectic silumin with high-intensity pulsed electron beam has been carried out. Multi-cycle fatigue tests were performed and irradiation mode made possible the increase in the silumin fatigue life more than 3.5 times was determined. Studies of the structure of the surface irradiation and surface fatigue fracture of silumin in the initial (unirradiated) state and after modification with intense pulsed electron beam were carried out by methods of scanning electron microscopy. It has been shown, that in mode of partial melting of the irradiation surface the modification process of silicon plates is accompanied by the formation of numerous large micropores along the boundary plate/matrix and microcracks located in the silicon plates. A multi-modal structure (grain size within 30-50 μm with silicon particles up to 10 μm located on the boundaries) is formed in stable melting mode, as well as subgrain structure in the form of crystallization cells from 100 to 250 μm in size). Formation of a multi-modal, multi-phase, submicro- and nanosize structure assisting to a significant increase in the critical length of the crack, the safety coefficient and decrease in step of cracks for loading cycle was the main cause for the increase in silumin fatigue life.

  16. Numerical analysis of the beam position monitor pickup for the Iranian light source facility

    Science.gov (United States)

    Shafiee, M.; Feghhi, S. A. H.; Rahighi, J.

    2017-03-01

    In this paper, we describe the design of a button type Beam Position Monitor (BPM) for the low emittance storage ring of the Iranian Light Source Facility (ILSF). First, we calculate sensitivities, induced power and intrinsic resolution based on solving Laplace equation numerically by finite element method (FEM), in order to find the potential at each point of BPM's electrode surface. After the optimization of the designed BPM, trapped high order modes (HOM), wakefield and thermal loss effects are calculated. Finally, after fabrication of BPM, it is experimentally tested by using a test-stand. The results depict that the designed BPM has a linear response in the area of 2×4 mm2 inside the beam pipe and the sensitivity of 0.080 and 0.087 mm-1 in horizontal and vertical directions. Experimental results also depict that they are in a good agreement with numerical analysis.

  17. Influence of surface light scattering in hydrophobic acrylic intraocular lenses on laser beam transmittance.

    Science.gov (United States)

    Shiraya, Tomoyasu; Kato, Satoshi; Minami, Keiichiro; Miyata, Kazunori

    2017-02-01

    The aim of this study was to experimentally examine the changes in the transmittances of photocoagulation lasers when surface light scattering increases in AcrySof intraocular lenses (IOLs). SA60AT IOLs (Alcon) were acceleratingly aging for 0, 3, 5, and 10 years to simulate surface light scattering, and the surface light-scattering intensities of both IOL surfaces were measured using a Scheimpflug photographer. The powers of laser beams that passed from a laser photocoagulator through the aged IOLs were measured at 532, 577, and 647 nm. Changes in the laser power and transmittance with the years of aging and the intensities of surface light scattering were examined. Although the intensity of surface light scattering increased with the years of aging, the laser power did not change with the years of aging (P > 0.30, Kruskal-Wallis test). There were no significant changes in the laser transmittance with the years of aging or the laser wavelength (P > 0.30 and 0.57, respectively). The intensity of surface light scattering revealed no significant association with the laser transmittance at any wavelength (P > 0.37, liner regression). The increases in the surface light scattering of the AcrySof IOLs would not influence retinal photocoagulation treatments for up to 10 years after implantation.

  18. Application of ESPRIT in Broad Beam HF Ground Wave Radar Sea Surface Current Mapping

    Institute of Scientific and Technical Information of China (English)

    Liu Dan-hong; Wu Xiong-bin; Wen Bi-yang; Cheng Feng

    2004-01-01

    HF surface wave radar system OSMAR2000 is a broad-beam sea-state detecting radar. ESPRIT (Estimation of Signal Parameters via Rotational Invariance Technique) algorithm is proposed to apply in DOA (direction of arrival) determination of sea echoes. The algorithm of ESPRIT is briefly introduced first. Then discussions are made on the technique for application in the OSMAR2000 framework. Numerical simulation results are presented to demonstrate the feasibility of radial current mapping based on this method. The algorithm manifests significant performance and computational advantages compared with that of MUSIC. Data acquired by OSMAR2000 are processed to give radial current map and the synthesized vector currents are compared with the in-situ measurement with traditional means. The results show the validity of ESPRIT application in DOA determination for broad-beam radar.

  19. Beam filter and splitter based on surface plasmon propagation in ring metal heterowaveguide

    Indian Academy of Sciences (India)

    Gaige Zheng; Linhua Xu; Yunyun Chen; Wei Su; Yuzhu Liu

    2014-12-01

    Surface plasmon polaritons (SPPs) beam filter (BF) and beam splitter (BS) constructed using metal heterostructures are proposed and demonstrated numerically. Both structures have a ring metal heterowaveguide, which is constructed by a metal cylinder and a ring dielectric cladding. The two-dimensional finite-difference time-domain (2D-FDTD) method is employed to study the properties of the proposed BF and BS, and the results show that SPPs can effectively propagate on bended plasmonic waveguides with dielectric claddings. By introducing dielectric and plasmonic waveguides on both sides of the resonant ring, SPPs can be efficiently excited at the output of the waveguide ring resonator (WRR) through mode coupling. The planar metal heterostructures provide a way for constructing various nanoscale counterparts of conventional planar integrated devices such as filters, splitters, resonators, sensors, optical switches, and so on.

  20. Dynamic simulation and efficiency analysis of beam pumping system

    Institute of Scientific and Technical Information of China (English)

    邢明明; 董世民; 童志雄; 田然凤; 陈慧玲

    2015-01-01

    An improved whole model of beam pumping system was built. In the detail, for surface transmission system (STS), a new mathematical model was established considering the influence of some factors on the STS’s torsional vibration, such as the time variation characteristic of equivalent stiffness of belt and equivalent rotational inertia of crank. For the sucker rod string (SRS), an improved mathematical model was built considering the influence of some parameters on the SRS’s longitudinal vibration, such as the nonlinear friction of plunger, hydraulic loss of pump and clearance leakage. The dynamic response and system efficiency of whole system were analyzed. The results show that there is a jumping phenomenon in the amplitude frequency curve, and the system.

  1. Optimization of the Shielded pair geometry for surface resistance measurements of the LHC beam screen

    CERN Document Server

    Tsutsui, H

    2000-01-01

    For the measurement of beam induced losses in the RF and microwaverange arising from the surface resistance of the LHC liner a dedicatedtechnique has been developed. A sample of the liner with a typicallength of about one meter is converted into a shielded pair coaxialresonator. The shielded pair approach using two parallel innerconductors, is required as both the conductivity of these two innerconductors and the conductivity of the inner liner surface change asa function of a DC magnetic field and temperature in a cryostat.These two conductors are operated in the odd and even mode, returning two Qvalues for each resonance. There are several degrees of freedom forthe diameter and lateral spacing of these two conductors. Taking into account end effects and different sources of mechanical positioning errors, parameters for an optimum geometry are discussed and the corresponding measurement errors on the surface resistance areestimated.

  2. Fast multifrequency focal beam analysis for 3D seismic acquisition geometry

    NARCIS (Netherlands)

    Wei, W.; Fu, L.; Blacquiere, G.

    2012-01-01

    A method for the efficient computation of multifrequency focal beams for 3D seismic acquisition geometry analysis has been developed. By computing them for all the frequency components of seismic data, single-frequency focal beams can be extended to multifrequency focal beams. However, this

  3. Structure of surface layers produced by non-vacuum electron beam boriding

    Energy Technology Data Exchange (ETDEWEB)

    Bataev, I.A., E-mail: ivanbataev@ngs.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Bataev, A.A., E-mail: bataev@adm.nstu.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Golkovski, M.G., E-mail: M.G.Golkovski@inp.nsk.su [Budker Institute of Nuclear Physics SB RAS, Lavrentieva prospect 11, 630090 Novosibirsk (Russian Federation); Krivizhenko, D.S., E-mail: dinylkaa@yandex.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Losinskaya, A.A., E-mail: anna.losinskaya@mail.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Lenivtseva, O.G., E-mail: lenivtseva_olga@mail.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation)

    2013-11-01

    The structure and mechanical properties of boronized layers produced on low carbon steel substrates by non-vacuum electron-beam cladding were studied. This process provides high performance and high thickness of coatings and can be used to process large workpieces. In this study, we investigated coatings obtained by one, two or three passes of the electron beam. The thickness of the coatings varied from 0.6 to 1.0 mm, and the maximum hardness achieved was 21 GPa. Structural analysis revealed the oriented growth of eutectic colonies near the primary crystals of iron borides, which was explained by the commonality of the boride phases in the primary Fe{sub 2}B and eutectic Fe{sub 2}B. The eutectic colonies formed during electron-beam cladding consisted of a continuous framework of borides crystals and segregations of α-Fe in the form of oriented fibers. Coatings produced by electron-beam cladding had higher contact-fatigue endurance than those produced by pack boriding.

  4. The Land Surface Temperature Synergistic Processor in BEAM: A Prototype towards Sentinel-3

    CERN Document Server

    Ruescas, Ana Belen; Fomferra, Norman; Brockmann, Carsten

    2016-01-01

    Land Surface Temperature (LST) is one of the key parameters in the physics of land-surface processes on regional and global scales, combining the results of all surface-atmosphere interactions and energy fluxes between the surface and the atmosphere. With the advent of the European Space Agency (ESA) Sentinel 3 (S3) satellite, accurate LST retrieval methodologies are being developed by exploiting the synergy between the Ocean and Land Colour Instrument (OLCI) and the Sea and Land Surface Temperature Radiometer (SLSTR). In this paper we explain the implementation in the Basic ENVISAT Toolbox for (A)ATSR and MERIS (BEAM) and the use of one LST algorithm developed in the framework of the Synergistic Use of The Sentinel Missions For Estimating And Monitoring Land Surface Temperature (SEN4LST) project. The LST algorithm is based on the split-window technique with an explicit dependence on the surface emissivity. Performance of the methodology is assessed by using MEdium Resolution Imaging Spectrometer/Advanced Alo...

  5. Influence of material removal programming on ion beam figuring of high-precision optical surfaces

    Science.gov (United States)

    Liao, Wenlin; Dai, Yifan; Xie, Xuhui

    2014-09-01

    Ion beam figuring (IBF) provides a nanometer/subnanometer precision fabrication technology for optical components, where the surface materials on highlands are gradually removed by the physical sputtering effect. In this deterministic method, the figuring process is usually divided into several iterations and the sum of the removed material in each iteration is expected to approach the ideally removed material as nearly as possible. However, we find that the material removal programming in each iteration would influence the surface error convergence of the figuring process. The influence of material removal programming on the surface error evolution is investigated through the comparative study of the contour removal method (CRM) and the geometric proportion removal method (PRM). The research results indicate that the PRM can maintenance the smoothness of the surface topography during the whole figuring process, which would benefit the stable operation of the machine tool and avoid the production of mid-to-high spatial frequency surface errors. Additionally, the CRM only has the corrective effect on the area above the contour line in each iteration, which would result in the nonuniform convergence of the surface errors in various areas. All these advantages distinguish PRM as an appropriate material removal method for ultraprecision optical surfaces.

  6. Evolution of Structural-Phase States in TiNi Surface Layers Synthesized by Electron Beam Treatment

    Directory of Open Access Journals (Sweden)

    L. L. Meisner

    2010-01-01

    Full Text Available The paper presents the results of X-ray diffraction analysis of nonequilibrium structural and elastic stress states in TiNi surface layers irradiated by low-energy electron beams. It is found that a surface layer with a mixed (2D columnar and 3D equiaxial submicrocrystalline structure is formed on the irradiated side of the TiNi specimens, and the volume fractions of the two structure types depend on the beam energy parameters and number of pulses. The B2 phase synthesized in the layer is characterized by lattice microstrain due to stresses of the first and second kinds (εI≈±1%, εII=0.25%, and the layer as such is an internal stress concentrator for underlying layers of the material. In the intermediate layer beneath the stress concentrator, relaxation of irradiation-induced internal stress takes place. It is shown that the main mechanism of the relaxation is partial B2→B19′ martensite transformation. The B19′ martensite phase in the intermediate layer decreases the microstrain in the conjugate B2 phase. The thickness of the layer in which the relaxation processes develop through the B2→B19′ martensite transformation is 10–15 μm.

  7. Ion beam induced luminescence analysis of painting pigments

    Energy Technology Data Exchange (ETDEWEB)

    Quaranta, A. [Universita di Trento, Dipartimento di Ingegneria dei Materiali e, delle Tecnologie Inustriali (DIMTI), via Mesiano 77, I-38050 Povo, Trento (Italy); Laboratori Nazionali di Legnaro - INFN, Via Universita 2, I-35020, Legnaro, Padova (Italy); E-mail: quaranta@ing.unitn.it; Salomon, J. [Centre de Recherche et de Restauration des Musees de France, CNRS UMR 171, rue des Pyramides, 75041 Paris Cedex 01 (France); Dran, J.C. [Centre de Recherche et de Restauration des Musees de France, CNRS UMR 171, rue des Pyramides, 75041 Paris Cedex 01 (France); Tonezzer, M. [Universita di Trento, Dipartimento di Ingegneria dei Materiali e, delle Tecnologie Inustriali (DIMTI), via Mesiano 77, I-38050 Povo, Trento (Italy); Laboratori Nazionali di Legnaro - INFN, Via Universita 2, I-35020, Legnaro, Padova (Italy); Della Mea, G. [Universita di Trento, Dipartimento di Ingegneria dei Materiali e, delle Tecnologie Inustriali (DIMTI), via Mesiano 77, I-38050 Povo, Trento (Italy); Laboratori Nazionali di Legnaro - INFN, Via Universita 2, I-35020, Legnaro, Padova (Italy)

    2007-01-15

    Ion beam induced luminescence (IBIL) has been exploited for the first time in the analysis of inorganic painting pigments. The elemental constituents of the different compounds have been determined by particle induced X-ray emission (PIXE). The acquisition time of each spectrum ranges from 100 ms to a few seconds, depending on the luminescence intensity. The luminescence features are fingerprints of the different compounds, thus identifying the provenience of pigments of the same nominal composition. Organic varnish layers do not affect the IBIL features, allowing the identification of pigments, like lapis-lazuli, whose identification with PIXE is hindered by the varnish. IBIL proved to be a technique complementary to PIXE in the archeometry and cultural heritage analysis fields.

  8. Measurement of surface recombination velocity for silicon solar cells using a scanning electron microscope with pulsed beam

    Science.gov (United States)

    Daud, T.; Cheng, L. J.

    1981-01-01

    The role of surface recombination velocity in the design and fabrication of silicon solar cells is discussed. A scanning electron microscope with pulsed electron beam was used to measure this parameter of silicon surfaces. It is shown that the surface recombination velocity, s, increases by an order of magnitude when an etched surface degrades, probably as a result of environmental reaction. A textured front-surface-field cell with a high-low junction near the surface shows the effect of minority carrier reflection and an apparent reduction of s, whereas a tandem-junction cell shows an increasing s value. Electric fields at junction interfaces in front-surface-field and tandem-junction cells acting as minority carrier reflectors or sinks tend to alter the value of effective surface recombination velocity for different beam penetration depths. A range of values of s was calculated for different surfaces.

  9. MICROSTRUCTURE AND MECHANICAL STRENGTH OF SURFACE ODS TREATED ZIRCALOY-4 SHEET USING LASER BEAM SCANNING

    Directory of Open Access Journals (Sweden)

    HYUN-GIL KIM

    2014-08-01

    Full Text Available The surface modification of engineering materials by laser beam scanning (LBS allows the improvement of properties in terms of reduced wear, increased corrosion resistance, and better strength. In this study, the laser beam scan method was applied to produce an oxide dispersion strengthened (ODS structure on a zirconium metal surface. A recrystallized Zircaloy-4 alloy sheet with a thickness of 2 mm, and Y2O3 particles of 10 μm were selected for ODS treatment using LBS. Through the LBS method, the Y2O3 particles were dispersed in the Zircaloy-4 sheet surface at a thickness of 0.4 mm, which was about 20% when compared to the initial sheet thickness. The mean size of the dispersive particles was 20 nm, and the yield strength of the ODS treated plate at 500°C was increased more than 65 % when compared to the initial state. This strength increase was caused by dispersive Y2O3 particles in the matrix and the martensite transformation of Zircaloy-4 matrix by the LBS.

  10. Localized surface grafting reactions on carbon nanofibers induced by gamma and e-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Evora, M.C., E-mail: cecilia@ieav.cta.br [Institute for Advanced Studies-IEAV/DCTA, Av. Cel Jose Alberto Albano do Amarante, 1-Putim, 12228-001 São Jose dos Campos, SP (Brazil); Araujo, J.R., E-mail: jraraujo@inmetro.gov.br [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Ferreira, E.H.M. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Strohmeier, B.R. [Thermo Fisher Scientific, 5225 Verona Road, Madison, WI 53711 (United States); Silva, L.G.A., E-mail: lgasilva@ipen.br [Institute for Nuclear and Energy Research- IPEN, Av. Prof lineu Prestes, 2242- Cidade Universitaria, 05508-000 SP (Brazil); Achete, C.A. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil)

    2015-04-30

    Graphical abstract: - Highlights: • Methodology for the functionalization of carbon nanofibers was investigated. • Two radiation sources were used to promote grafting reactions: gamma and electron beam. • We report the optimum inhibitor concentration to achieve the functionalization. • Surface of carbon nanofibers showed an increase of oxygen content after irradiation. • The radiation-induced graphitization did not damage the overall sp{sup 2} structure. - Abstract: Electron beam and gamma-ray irradiation have potential application to modify the carbon fiber nanostructures in order to produce useful defects in the graphitic structure and create reactive sites. In this study, the methodology to functionalize carbon nanofiber (CNF), via a radiation process and using acrylic acid as a source of oxygen functional groups, was investigated. The samples were submitted to a direct grafting radiation process with electron beam and gamma-ray source. Several parameters were changed such as: acrylic acid concentration, radiation dose and percentage of inhibitor necessary to achieve functionalization, with higher percentage of oxygen functional groups on CNF surface, and better dispersion. The better results achieved were when mixing CNF in a solution of acrylic acid with 6% of inhibitor (FeSO{sub 4}·7H{sub 2}O) and irradiated at 100 kGy. The samples were characterized by X-ray photoelectron spectroscopy and the surface composition (atomic%) showed a significant increase of oxygen content for the samples after irradiation. Also, the dispersion of the functionalized CNF in water was stable during months which may be a good indication that the functionalization process of CNF via ionizing radiation was successful.

  11. Application of the Same Beam Interferometry Measurement in Relative Position Determination on Lunar Surface

    Directory of Open Access Journals (Sweden)

    HUANG Anyi

    2015-09-01

    Full Text Available Based on the principle and observation model of the same beam interferometry measurement, observation equations of differential time delay and time delay rate for targets on lunar surface are proposed. Restriction of appointed height and digital lunar height model is introduced and a Kalman filter with restriction to determine the relative position is put forward. By data simulation, the arithmetic is then validated and evaluated, which could fleetly and accurately determine the relative position between rover and lander. Low precision of the lander's position is required in the calculation.

  12. Stabilization of a cold cathode electron beam glow discharge for surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mingolo, N.; Gonzalez, C.R. [Lab. de Haces Dirigidos, Depto. de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Martinez, O.E. [Lab. de Electronica Cuantica, Depto. de Fisica, Universidad de Buenos Aires, Pabellon 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Rocca, J.J. [Department of Electrical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)

    1997-10-01

    We have demonstrated that the reproducibility of electron beam pulses generated by a high power, cold cathode glow discharge is greatly improved by adding a small continuous keep-alive discharge current. A current of the order of 200 {mu}A was found to limit the shot to shot current variation to within 1.5{percent}. This stabilization in turn reduces by an order of magnitude the fluctuations of the energy density deposited on the target, demonstrating a reliable energy source for surface treatment. {copyright} {ital 1997 American Institute of Physics.}

  13. Should cavitation in proximal surfaces be reported in cone beam computed tomography examination?

    DEFF Research Database (Denmark)

    Sansare, K; Singh, D; Sontakke, S

    2014-01-01

    Aim: A clinical study was done to assess the clinical diagnostic accuracy of cone beam computed tomography (CBCT) in detecting proximal cavitated carious lesions in order to determine whether cavitation should be reported when a CBCT examination is available. Materials and Methods: 79 adjacent...... proximal surfaces without restorations in permanent teeth were examined. Patients suspected to have carious lesions after a visual clinical and a bitewing examination participated in a CBCT examination (Kodak 9000 3D, 5 × 3.7 cm field of view, voxel size 0.07 mm). Ethical approval and informed consent were...

  14. Calibration of eddy current carburization measurements in ethylene production tubes using ion beam analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, K J [Materials Performance Technologies, Industrial Research Ltd, PO Box 31-310, Lower Hutt (New Zealand); Trompetter, W J [Rafter Laboratory, Institute of Geological and Nuclear Sciences, PO Box 31-312, Lower Hutt (New Zealand)

    2004-02-07

    Nuclear reaction analysis using a {sup 12}C(d, p{sub 0}){sup 13}C reaction and a {sup 16}O(d, p{sub 1}){sup 17}O reaction, with 1.02 MeV deuterons in an accelerator microprobe, has been used to produce quantitative linescans of the carbon and oxygen levels in ex-service ethylene pyrolysis tubes of HPM, HK40 and Manaurite XM alloy. Particle induced x-ray emission in the ion beam microprobe and energy dispersive analysis of x-rays in a scanning electron microscope were used for linescans of the heavier elements (Cr, Ni, Fe, Si and Ti). The composition linescans were used to calibrate the response and accuracy of an eddy current probe system for measuring carburization near the inner surface of the tubes. The influence of the ferromagnetic outer oxide surface layers has been clarified. A two-dimensional ANSYS finite element model (FEM) was used for interpretation of the eddy current scans. Good correlation was obtained between the ion beam analysis results, the impedance scans and the FEM.

  15. Calibration of eddy current carburization measurements in ethylene production tubes using ion beam analysis

    Science.gov (United States)

    Stevens, K. J.; Trompetter, W. J.

    2004-02-01

    Nuclear reaction analysis using a 12C(d, p0)13C reaction and a 16O(d, p1)17O reaction, with 1.02 MeV deuterons in an accelerator microprobe, has been used to produce quantitative linescans of the carbon and oxygen levels in ex-service ethylene pyrolysis tubes of HPM, HK40 and Manaurite XM alloy. Particle induced x-ray emission in the ion beam microprobe and energy dispersive analysis of x-rays in a scanning electron microscope were used for linescans of the heavier elements (Cr, Ni, Fe, Si and Ti). The composition linescans were used to calibrate the response and accuracy of an eddy current probe system for measuring carburization near the inner surface of the tubes. The influence of the ferromagnetic outer oxide surface layers has been clarified. A two-dimensional ANSYS finite element model (FEM) was used for interpretation of the eddy current scans. Good correlation was obtained between the ion beam analysis results, the impedance scans and the FEM.

  16. Investigation of surface characteristics evolution and laser damage performance of fused silica during ion-beam sputtering

    Science.gov (United States)

    Xu, Mingjin; Dai, Yifan; Zhou, Lin; Shi, Feng; Wan, Wen; Xie, Xuhui; Sui, Tingting

    2016-08-01

    Surface characteristics have great influence on the optical properties especially the laser radiation resistivity of optics. In this paper, the surface characteristics evolutions of fused silica during ion-beam sputtering and their effects on the laser damage performance were investigated. The results show that roughness change is strongly removal depth dependent and a super-smooth surface (0.25 nm RMS) can be obtained by the ion-induced smoothing effect. The concentration of metal impurities (especially Ce element) in subsurface can be effectively decreased after the removal of polishing re-deposition layer. During ion-beam sputtering process, the plastic scratches can be removed while the brittle cracks can be broadened and passivated without increase in the depth direction. Laser damage threshold of fused silica improved by 36% after ion-beam sputtering treatment. Research results have a guiding significance for ion-beam sputtering process technology of fused silica optics.

  17. Near Surface Mounted Composites for Flexural Strengthening of Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Md. Akter Hosen

    2016-03-01

    Full Text Available Existing structural components require strengthening after a certain period of time due to increases in service loads, errors in design, mechanical damage, and the need to extend the service period. Externally-bonded reinforcement (EBR and near-surface mounted (NSM reinforcement are two preferred strengthening approach. This paper presents a NSM technique incorporating NSM composites, namely steel and carbon fiber-reinforced polymer (CFRP bars, as reinforcement. Experimental and analytical studies carried out to explore the performance of reinforced concrete (RC members strengthened with the NSM composites. Analytical models were developed in predicting the maximum crack spacing and width, concrete cover separation failure loads, and deflection. A four-point bending test was applied on beams strengthened with different types and ratios of NSM reinforcement. The failure characteristics, yield, and ultimate capacities, deflection, strain, and cracking behavior of the beams were evaluated based on the experimental output. The test results indicate an increase in the cracking load of 69% and an increase in the ultimate load of 92% compared with the control beam. The predicted result from the analytical model shows good agreement with the experimental result, which ensures the competent implementation of the present NSM-steel and CFRP technique.

  18. A Modeling and Data Analysis of Laser Beam Propagation in the Maritime Domain

    Science.gov (United States)

    2015-05-18

    A TRIDENT SCHOLAR PROJECT REPORT NO. 433 A Modeling and Data Analysis of Laser Beam Propagation in the Maritime Domain by...433 (2015) A MODELING AND DATA ANALYSIS OF LASER BEAM PROPAGATION IN THE MARITIME DOMAIN by Midshipman 1/C Benjamin C. Etringer United States Naval...2. REPORT TYPE 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE A Modeling and Data Analysis of Laser Beam Propagation in the Maritime

  19. Investigating Surface Effects on Thermomechanical Behavior of Embedded Circular Curved Nanosize Beams

    Directory of Open Access Journals (Sweden)

    Farzad Ebrahimi

    2016-01-01

    Full Text Available To investigate the surface effects on thermomechanical vibration and buckling of embedded circular curved nanosize beams, nonlocal elasticity model is used in combination with surface properties including surface elasticity, surface tension, and surface density for modeling the nanoscale effect. The governing equations are determined via the energy method. Analytically Navier method is utilized to solve the governing equations for simply supported nanobeam at both ends. Solving these equations enables us to estimate the natural frequency and critical buckling load for circular curved nanobeam including Winkler and Pasternak elastic foundations and under the effect of a uniform temperature change. The results determined are verified by comparing the results with available ones in literature. The effects of various parameters such as nonlocal parameter, surface properties, Winkler and Pasternak elastic foundations, temperature, and opening angle of circular curved nanobeam on the natural frequency and critical buckling load are successfully studied. The results reveal that the natural frequency and critical buckling load of circular curved nanobeam are significantly influenced by these effects.

  20. Test Beam Data Analysis for a Timepix3 Readout Chip

    CERN Document Server

    Williams, Morag

    2016-01-01

    The vertex and tracker detector R&D for a future linear collider (CLICdp) aims at developing new silicon sensor technologies. The EP-LCD group has been helping develop a novel pixel detector chip called the Timepix3 with a very thick active silicon layer (675 μm). This thick detector can be used to reconstruct the track incidence angle using the charge drift-time information. To evaluate the principle, test beam data was taken in October 2015 and June 2016 with the Timepix3 at various angles to the beam. The data was analysed to evaluate the sensors performance in calculating the track incidence angle. The device angle was determined using three methods: the first using the cluster size information, secondly using the timing information, and finally using a multivariate analysis technique. The timing method proved the principle of the Timepix3 track angle measurements but the MVA method was found to give much better results, especially for smaller angles, than the other two methods and requires fewer cal...

  1. Proteomic analysis of proton beam irradiated human melanoma cells.

    Directory of Open Access Journals (Sweden)

    Sylwia Kedracka-Krok

    Full Text Available Proton beam irradiation is a form of advanced radiotherapy providing superior distributions of a low LET radiation dose relative to that of photon therapy for the treatment of cancer. Even though this clinical treatment has been developing for several decades, the proton radiobiology critical to the optimization of proton radiotherapy is far from being understood. Proteomic changes were analyzed in human melanoma cells treated with a sublethal dose (3 Gy of proton beam irradiation. The results were compared with untreated cells. Two-dimensional electrophoresis was performed with mass spectrometry to identify the proteins. At the dose of 3 Gy a minimal slowdown in proliferation rate was seen, as well as some DNA damage. After allowing time for damage repair, the proteomic analysis was performed. In total 17 protein levels were found to significantly (more than 1.5 times change: 4 downregulated and 13 upregulated. Functionally, they represent four categories: (i DNA repair and RNA regulation (VCP, MVP, STRAP, FAB-2, Lamine A/C, GAPDH, (ii cell survival and stress response (STRAP, MCM7, Annexin 7, MVP, Caprin-1, PDCD6, VCP, HSP70, (iii cell metabolism (TIM, GAPDH, VCP, and (iv cytoskeleton and motility (Moesin, Actinin 4, FAB-2, Vimentin, Annexin 7, Lamine A/C, Lamine B. A substantial decrease (2.3 x was seen in the level of vimentin, a marker of epithelial to mesenchymal transition and the metastatic properties of melanoma.

  2. Crossed beam reactive scattering of oxygen atoms and surface scattering studies of gaseous condensation

    Energy Technology Data Exchange (ETDEWEB)

    Sibener, S.J.

    1979-09-01

    A high pressure, radio frequency discharge nozzle beam source was developed for the production of very intense (greater than or equal to 10/sup 18/ atoms sr/sup -1/ sec/sup -1/) supersonic beams of oxygen atoms. This source is capable of producing seeded beams of ground state O(/sup 3/P/sub J/) atoms when dilute oxygen-argon mixtures are used, with molecular dissociation levels exceeding 80% being realized for operation at pressures up to 350 torr. When dilute oxygen-helium mixtures are employed both ground state O(/sup 3/P/sub J/) and excited state O(/sup 1/D/sub 2/) atoms are present in the terminal beam, with molecular dissociation levels typically exceeding 60% being achieved for operation at pressures up to 200 torr. Atomic oxygen mean translational energies from 0.14 to 0.50 eV were obtained using the seeded beams technique, with Mach numbers as high as 10 (FWHM ..delta.. v/v approx. = 20%) being realized. The IC1, CF/sub 3/I, C/sub 6/H/sub 6/, and C/sub 6/D/sub 6/ reactions are discussed in detail. The IC1 and CF/sub 3/I studies have enabled us to determine an improved value for the bond energy of the IO radical: D/sub o/(IO) = 55 +- 2 kcal/mole. The IO product angular and velocity distributions have been used to generate center-of-mass flux contour maps, which indicate that these two reactions proceed via relatively long-lived collision complexes whose mean lifetimes are slightly shorter than their respective rotational periods. The O(/sup 3/P/sub J/) + C/sub 6/H/sub 6/ and C/sub 6/D/sub 6/ reactions were studied in order to elucidate the reaction mechanism, and, in particular, to identify the primary reaction products produced in these reactions. Finally, a series of beam-surface scattering experiments are described which examined the internal and translational energy dependence of molecular condensation probabilities for collisions involving either CC1/sub 4/ or SF/sub 6/ and their respective condensed phases. 117 references. (JFP)

  3. Vibrational Analysis of a Shipboard Free Electron Laser Beam Path

    Science.gov (United States)

    2011-12-01

    42 4. Beam Path “ Racetrack ” ....................................................................44 a. Wave...43 Figure 33. Shock Excitation Beam Dump Z Direction Displacement ..............................44 Figure 34. Top View of Beam Path “ Racetrack ...magnets to merge into the “ racetrack ” prior to entering the LINAC: The motion of the injector assembly and magnets relative to the merge point of the

  4. A Simplified Analysis of the Brazier Effect in Composite Beams

    DEFF Research Database (Denmark)

    Damkilde, Lars; Lund, B.

    2009-01-01

    In the design of windturbine blades composite beams are often used as the load bearing element. The beam is primarily subjected to bending moments, and the deformations are relatively large. The large displacements result in a kind of ovalization of the beam section, the so-called Brazier effect...

  5. Preventing colloidal fouling in reverse osmosis and nano filtration system. Application of electron beam surface analysis; Prevencion del ensuciamiento coloidal en sistemas de osmosis inversa y nanofiltracion. Aplicacion del analisis de superficies con haces de electrones.

    Energy Technology Data Exchange (ETDEWEB)

    Sanz Ataz, J.; Guerrero Gallego, L.; Taberna Camprubi, E.; Pena Garcia, N.M; Carulla Contreras, C.; Blavia Bergos, J.

    2003-07-01

    Particulate matter in natural waters and wastewaters can cause fouling in reverse osmosis and nano filtration membranes. Common foulants includes organic and inorganic colloids; hydrous aluminum and iron silicates, silt, iron and manganese oxides, calcium carbonate, microorganisms, polysaccharides, lipoproteins, biological debris, etc. Predicting fouling of dispersed materials on membrane surface and brine flow channels uses the silt density index (SDI) and modified fouling index (MFI). Scanning electron microscopy (SEM) coupled with energy X-ray microanalysis (EDX) of SDI filters contributes to obtain information about shape, size and chemical composition of foulants and cake layer. (Author) 6 refs.

  6. Global Analysis of Minimal Surfaces

    CERN Document Server

    Dierkes, Ulrich; Tromba, Anthony J

    2010-01-01

    Many properties of minimal surfaces are of a global nature, and this is already true for the results treated in the first two volumes of the treatise. Part I of the present book can be viewed as an extension of these results. For instance, the first two chapters deal with existence, regularity and uniqueness theorems for minimal surfaces with partially free boundaries. Here one of the main features is the possibility of 'edge-crawling' along free parts of the boundary. The third chapter deals with a priori estimates for minimal surfaces in higher dimensions and for minimizers of singular integ

  7. Design and Analysis of Diffractive Axicons for Gaussian Beam Illumination

    Institute of Scientific and Technical Information of China (English)

    PU Jixiong; Shojiro Nemoto

    2001-01-01

    The diffractive axicon for the illumination with Gaussian beams is designed. The stationary phase method and the numerical calculation are used to analyze the diffraction integral describing the diffraction field. It is shown that with the Gaussian beam illumination of a smaller beam radius, the axicon can produces the uniform-axial-intensity with the lower oscillation frequency and the smaller oscillation amplitude. In addition, with the Gaussian beam illumination of a suitable beam radius, we can achieve the more uniform central-core width.

  8. Surface Nanocrystallization of 3Cr13 Stainless Steel Induced by High-Current Pulsed Electron Beam Irradiation

    OpenAIRE

    2013-01-01

    The nanocrystalline surface was produced on 3Cr13 martensite stainless steel surface using high-current pulsed electron beam (HCPEB) technique. The structures of the nanocrystallized surface were characterized by X-ray diffraction and electron microscopy. Two nanostructures consisting of fine austenite grains (50–150 nm) and very fine carbides precipitates are formed in melted surface layer after multiple bombardments via dissolution of carbides and crater eruption. It is demonstrated that th...

  9. Analysis and control of the photon beam position at PLS-II

    Energy Technology Data Exchange (ETDEWEB)

    Ko, J.; Kim, I.-Y.; Kim, C.; Kim, D.-T.; Huang, J.-Y.; Shin, S., E-mail: tlssh@postech.ac.kr [POSTECH, Pohang, Kyungbuk 790-784 (Korea, Republic of)

    2016-02-18

    The variation of the photon beam position in a beamline, which is a critical issue for user experiments, is analyzed and corrected through the correlation link with the electron beam position in the storage ring. At third-generation light sources, the photon beam position stability is a critical issue for user experiments. In general, photon beam position monitors are developed to detect the real photon beam position, and the position is controlled by a feedback system in order to maintain the reference photon beam position. At Pohang Light Source II, a photon beam position stability of less than 1 µm r.m.s. was achieved for a user service period in the beamline, where the photon beam position monitor is installed. Nevertheless, a detailed analysis of the photon beam position data was necessary in order to ensure the performance of the photon beam position monitor, since it can suffer from various unknown types of noise, such as background contamination due to upstream or downstream dipole radiation, and undulator gap dependence. This paper reports the results of a start-to-end study of the photon beam position stability and a singular value decomposition analysis to confirm the reliability of the photon beam position data.

  10. Thin film surface reconstruction analysis

    Energy Technology Data Exchange (ETDEWEB)

    Imperatori, P. [CNR, Monterotondo Stazione, Rome (Italy). Istituto di Chimica dei materiali

    1996-09-01

    The study of the atomic structure of surfaces and interfaces is a fundamental step in the knowledge and the development of new materials. Among the several surface-sensitive techniques employed to characterise the atomic arrangements, grazing incidence x-ray diffraction (GIXD) is one of the most powerful. With a simple data treatment, based on the kinematical theory, and using the classical methods of x-ray bulk structure determination, it gives the atomic positions of atoms at a surface or an interface and the atomic displacements of subsurface layers for a complete determination of the structure. In this paper the main features of the technique will be briefly reviewed and selected of application to semiconductor and metal surfaces will be discussed.

  11. Gap Surface Plasmon Waveguide Analysis

    DEFF Research Database (Denmark)

    Nielsen, Michael Grøndahl; Bozhevolnyi, Sergey I.

    2014-01-01

    Plasmonic waveguides supporting gap surface plasmons (GSPs) localized in a dielectric spacer between metal films are investigated numerically and the waveguiding properties at telecommunication wavelengths are presented. Especially, we emphasize that the mode confinement can advantageously...

  12. Convergent-beam low energy electron diffraction (CBLEED) and the measurement of surface dipole layers.

    Science.gov (United States)

    Spence, J C H; Poon, H C; Saldin, D K

    2004-02-01

    We propose the formation of LEED patterns using a highly convergent beam forming a probe of nanometer dimensions. A reflection rocking curve may then be recorded in many diffraction orders simultaneously. Multiple scattering calculations show that the intensity variations within these rocking curves is as sensitive to the parameters describing the surface dipole layer as conventional I/V scans. However the data may be collected from areas sufficiently small to avoid defects and surface steps, radiation damage controlled by use of low voltages, and the information depth selected by choice of the (constant) voltage. We briefly discuss also the application of this method to oxides and the formation of atomic-resolution scanning images in an idealized instrument in which coherent diffracted LEED orders overlap.

  13. Effect of ion and electron beam irradiation on surface morphology and optical properties of PVA

    Institute of Scientific and Technical Information of China (English)

    HM Eyssa; MO sman; SAK andil; MMA bdelrahman

    2015-01-01

    Polyvinyl alcohol (PVA) is a well-known friendly polymer for paper-making, textiles, and a variety of coat-ings, biomedical applications such as artificial pancreas, synthetic vitreous body, wound dressing, artificial skin, and cardiovascular device. In this paper, ion/electron beam is employed to get insight into the irradiation effect on surface morphology and optical properties of PVA polymer. UV-Vis spectra are recorded to investigate the effect of induced defects on the optical band gap and the formed carbon clusters size. Scanning electron microscopy (SEM) is used to relate and investigate surface morphology and optical properties of the target poly-mer with different doses (15, 30 and 60 min). Also, PVA polymer is subjected to theoretical studies by using semi-empirical PM7 quantum chemical method.

  14. Coherent reflection of He atom beams from rough surfaces at near-grazing incidence

    CERN Document Server

    Zhao, Bum Suk; Meijer, Gerard; Schöllkopf, Wieland

    2010-01-01

    We here report coherent reflection of thermal He atom beams from various microscopically rough surfaces at grazing incidence. For a sufficiently small normal component $k_z$ of the incident wave-vector of the atom the reflection probability is found to be a function of $k_z$ only. This behavior is explained by quantum-reflection at the attractive branch of the Casimir-van der Waals interaction potential. For larger values of $k_z$ the overall reflection probability decreases rapidly and is found to also depend on the parallel component $k_x$ of the wave-vector. The material specific $k_x$ dependence for this classical reflection at the repulsive branch of the potential is explained qualitatively in terms of the averaging-out of the surface roughness under grazing incidence conditions.

  15. Coherent Reflection of He Atom Beams from Rough Surfaces at Grazing Incidence

    Science.gov (United States)

    Zhao, Bum Suk; Schewe, H. Christian; Meijer, Gerard; Schöllkopf, Wieland

    2010-09-01

    We report coherent reflection of thermal He atom beams from various microscopically rough surfaces at grazing incidence. For a sufficiently small normal component kz of the incident wave vector of the atom the reflection probability is found to be a function of kz only. This behavior is explained by quantum reflection at the attractive branch of the Casimir-van der Waals interaction potential. For larger values of kz the overall reflection probability decreases rapidly and is found to also depend on the parallel component kx of the wave vector. The material specific kx dependence for this classic reflection at the repulsive branch of the potential is discussed in terms of an averaging out of the surface roughness under grazing incidence conditions.

  16. Ion beam analysis of ground coffee and roasted coffee beans

    Science.gov (United States)

    Debastiani, R.; dos Santos, C. E. I.; Yoneama, M. L.; Amaral, L.; Dias, J. F.

    2014-01-01

    The way that coffee is prepared (using roasted ground coffee or roasted coffee beans) may influence the quality of beverage. Therefore, the aim of this work is to use ion beam techniques to perform a full elemental analysis of packed roasted ground coffee and packed roasted coffee beans, as well as green coffee beans. The samples were analyzed by PIXE (particle-induced X-ray emission). Light elements were measured through RBS (Rutherford backscattering spectrometry) experiments. Micro-PIXE experiments were carried out in order to check the elemental distribution in the roasted and green coffee beans. In general, the elements found in ground coffee were Mg, P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Rb and Sr. A comparison between ground coffee and grinded roasted beans shows significant differences for several elements. Elemental maps reveal that P and K are correlated and practically homogeneously distributed over the beans.

  17. Ion beam analysis of materials in the PBMR reactor

    Science.gov (United States)

    Malherbe, Johan B.; Friedland, E.; van der Berg, N. G.

    2008-04-01

    South Africa is developing a new type of high temperature nuclear reactor, the so-called pebble bed modular reactor (PBMR). The planned reactor outlet temperature of this gas-cooled reactor is approximately 900 °C. This high temperature places some severe restrictions on materials, which can be used. The name of the reactor is derived from the form of the fuel elements, which are in the form of pebbles, each with a diameter of 60 mm. Each pebble is composed of several thousands of coated fuel particles. The coated particle consists of a nucleus of UO2 surrounded by several layers of different carbons and SiC. The diameter of the fuel particles is 0.92 mm. A brief review will be given of the advantages of this nuclear reactor, of the materials in the fuel elements and their analysis using ion beam techniques.

  18. Water resistance and surface morphology of synthetic fabrics covered by polysiloxane/acrylate followed by electron beam irradiation

    CERN Document Server

    El-Naggar, A M; Mohammed, S S; Alam, E A

    2003-01-01

    Different synthetic fabrics were treated by electron beam surface coating with two formulations based on polydimethylsiloxane (PDMS) and polystyrene (PS) or poly(methyl methacrylate) (PMMA) oligomers. The water resistance properties were investigated in terms of the percentage of water repellency and absorption. Also, the surface coated fabrics were examined by scanning electron microscopy/microscope (SEM) connected to an energy dispersive X-ray (EDX) unit to determine the percentage atomic contents of elements. The results showed that the adhesion of the polysiloxane formulation to the surface depends largely on the kind of acrylate oligomer and textile fabric as indicated by the EDX analysis for silicon. In this regard, PDMS/PS formulation is more compatible with polyester and nylon-6 fabrics than PDMS/PMMA one. However, it was found that PDMS/PMMA formulation is more compatible with cotton/polyester blend than PDMS/PS. The SEM micrographs give further supports to the EDX analysis. On the basis of the perce...

  19. Water resistance and surface morphology of synthetic fabrics covered by polysiloxane/acrylate followed by electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    El-Naggar, A.M. E-mail: ab_nagga@yahoo.com; Zohdy, M.H.; Mohammed, S.S.; Alam, E.A

    2003-04-01

    Different synthetic fabrics were treated by electron beam surface coating with two formulations based on polydimethylsiloxane (PDMS) and polystyrene (PS) or poly(methyl methacrylate) (PMMA) oligomers. The water resistance properties were investigated in terms of the percentage of water repellency and absorption. Also, the surface coated fabrics were examined by scanning electron microscopy/microscope (SEM) connected to an energy dispersive X-ray (EDX) unit to determine the percentage atomic contents of elements. The results showed that the adhesion of the polysiloxane formulation to the surface depends largely on the kind of acrylate oligomer and textile fabric as indicated by the EDX analysis for silicon. In this regard, PDMS/PS formulation is more compatible with polyester and nylon-6 fabrics than PDMS/PMMA one. However, it was found that PDMS/PMMA formulation is more compatible with cotton/polyester blend than PDMS/PS. The SEM micrographs give further supports to the EDX analysis. On the basis of the percentage of water repellency and absorption, polyester fabric displayed the highest water resistance properties among the studied textile fabrics regardless of the used polysiloxane formulation.

  20. SECTION 6.2 SURFACE TOPOGRAPHY ANALYSIS

    DEFF Research Database (Denmark)

    Seah, M. P.; De Chiffre, Leonardo

    2005-01-01

    Surface physical analysis, i.e. topography characterisation, encompasses measurement, visualisation, and quantification. This is critical for both component form and for surface finish at macro-, micro- and nano-scales. The principal methods of surface topography measurement are stylus profilomet...

  1. Development of a surface ionization source for the production of radioactive alkali ion beams in SPIRAL

    Energy Technology Data Exchange (ETDEWEB)

    Eleon, C. [GANIL, CEA/DSM CNRS/IN2P3, Bd H. Becquerel, BP 55027, 14076 CAEN cedex 5 (France)], E-mail: sceleon@triumf.ca; Jardin, P.; Gaubert, G.; Saint-Laurent, M.-G.; Alcantara-Nunez, J.; Alves Conde, R.; Barue, C.; Boilley, D.; Cornell, J. [GANIL, CEA/DSM CNRS/IN2P3, Bd H. Becquerel, BP 55027, 14076 CAEN cedex 5 (France); Delahaye, P. [3 CERN ISOLDE, 1211 Geneva 23 (Switzerland); Dubois, M.; Jacquot, B.; Leherissier, P.; Leroy, R.; Lhersonneau, G. [GANIL, CEA/DSM CNRS/IN2P3, Bd H. Becquerel, BP 55027, 14076 CAEN cedex 5 (France); Marie-Jeanne, M. [3 CERN ISOLDE, 1211 Geneva 23 (Switzerland); Maunoury, L. [CIRIL, Bd H. Becquerel, BP 55027, 14076 CAEN cedex 5 (France); Pacquet, J.Y.; Pellemoine, F. [GANIL, CEA/DSM CNRS/IN2P3, Bd H. Becquerel, BP 55027, 14076 CAEN cedex 5 (France); Pierret, C. [CIRIL, Bd H. Becquerel, BP 55027, 14076 CAEN cedex 5 (France)] (and others)

    2008-10-15

    In the framework of the production of radioactive alkali ion beams by the isotope separation on-line (ISOL) method in SPIRAL I, a surface ionization source has been developed at GANIL to produce singly-charged ions of Li, Na and K. This new source has been designed to work in the hostile environment whilst having a long lifetime. This new system of production has two ohmic heating components: the first for the target oven and the second for the ionizer. The latter, being in carbon, offers high reliability and competitive ionization efficiency. This surface ionization source has been tested on-line using a {sup 48}Ca primary beam at 60.3 A MeV with an intensity of 0.14 pA. The ionization efficiencies obtained for Li, Na and K are significantly better than the theoretical values of the ionization probability per contact. The enhanced efficiency, due to the polarization of the ionizer, is shown to be very important also for short-lived isotopes. In the future, this source will be associated with the multicharged electron-cyclotron-resonance (ECR) ion source NANOGAN III for production of multicharged alkali ions in SPIRAL. The preliminary tests of the set up are also presented in this contribution.

  2. Three-dimensional analysis of the surface mode supported in Čerenkov and Smith-Purcell free-electron lasers

    Science.gov (United States)

    Kalkal, Yashvir; Kumar, Vinit

    2016-06-01

    In Čerenkov and Smith-Purcell free-electron lasers (FELs), a resonant interaction between the electron beam and the copropagating surface mode can produce a copious amount of coherent terahertz radiation. We perform a three-dimensional (3D) analysis of the surface mode, taking the effect of attenuation into account, and set up 3D Maxwell-Lorentz equations for both these systems. Based on this analysis, we determine the requirements on the electron beam parameters, i.e., beam emittance, beam size and beam current for the successful operation of a Čerenkov FEL.

  3. Three-dimensional analysis of the surface mode supported in $\\boldmath{\\check{\\text{C}}}$erenkov and Smith-Purcell free-electron lasers

    CERN Document Server

    Kalkal, Yashvir

    2015-01-01

    In $\\check{\\text{C}}$erenkov and Smith-Purcell free-electron lasers (FELs), a resonant interaction between the electron beam and the co-propagating surface mode can produce copious amount of coherent terahertz (THz) radiation. We perform a three-dimensional (3D) analysis of the surface mode, taking the effect of attenuation into account, and set up 3D Maxwell-Lorentz equations for both these systems. Based on this analysis, we determine the requirements on the electron beam parameters, i.e., beam emittance, beam size and beam current for the successful operation of a $\\check{\\text{C}}$erenkov FEL.

  4. Automatic Beam Path Analysis of Laser Wakefield Particle Acceleration Data

    Energy Technology Data Exchange (ETDEWEB)

    Rubel, Oliver; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Wu, Kesheng; Prabhat,; Weber, Gunther H.; Ushizima, Daniela M.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes

    2009-10-19

    Numerical simulations of laser wakefield particle accelerators play a key role in the understanding of the complex acceleration process and in the design of expensive experimental facilities. As the size and complexity of simulation output grows, an increasingly acute challenge is the practical need for computational techniques that aid in scientific knowledge discovery. To that end, we present a set of data-understanding algorithms that work in concert in a pipeline fashion to automatically locate and analyze high energy particle bunches undergoing acceleration in very large simulation datasets. These techniques work cooperatively by first identifying features of interest in individual timesteps, then integrating features across timesteps, and based on the information derived perform analysis of temporally dynamic features. This combination of techniques supports accurate detection of particle beams enabling a deeper level of scientific understanding of physical phenomena than hasbeen possible before. By combining efficient data analysis algorithms and state-of-the-art data management we enable high-performance analysis of extremely large particle datasets in 3D. We demonstrate the usefulness of our methods for a variety of 2D and 3D datasets and discuss the performance of our analysis pipeline.

  5. Nanoscale pattern formation at surfaces under ion-beam sputtering: A perspective from continuum models

    Energy Technology Data Exchange (ETDEWEB)

    Cuerno, Rodolfo, E-mail: cuerno@math.uc3m.e [Departamento de Matematicas and Grupo Interdisciplinar de Sistemas Complejos (GISC), Universidad Carlos III de Madrid, Avenida de la Universidad 30, E-28911 Leganes, Madrid (Spain); Castro, Mario [GISC and Grupo de Dinamica No Lineal (DNL), Escuela Tecnica Superior de Ingenieria (ICAI), Universidad Pontificia Comillas, E-28015 Madrid (Spain); Munoz-Garcia, Javier [Systems Biology Ireland and GISC, University College Dublin, Belfield, Dublin 4 (Ireland); Gago, Raul; Vazquez, Luis [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, E-28049 Madrid (Spain)

    2011-05-01

    Although reports on surface nanostructuring of solid targets by low to medium energy ion irradiation date back to the 1960s, only with the advent of high resolution tools for surface/interface characterization has the high potential of this procedure been recognized as a method for efficient production of surface patterns. Such morphologies are made up of periodic arrangements of nanometric sized features, like ripples and dots, with interest for technological applications due to their electronic, magnetic, and optical properties. Thus, roughly for the last ten years large efforts have been directed towards harnessing this nanofabrication technique. However, and particularly in view of recent experimental developments, we can say that the basic mechanisms controlling these pattern formation processes remain poorly understood. The lack of nanostructuring at low angles of incidence on some pure monoelemental targets, the role of impurities in the surface dynamics and other recent observations are challenging the classic view on the phenomenon as the mere interplay between the curvature dependence of the sputtering yield and surface diffusion. We review the main attempts at a theoretical (continuum) description of these systems, with emphasis on recent developments. Strong hints already exist that the nature of the morphological instability has to be rethought as originating in the material flow that is induced by the ion beam.

  6. Analysis of laser alloyed surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, D.C.; Augustyniak, W.M.; Buene, L.; Draper, C.W.; Poate, J.M.

    1981-04-01

    Surface alloys of precious metals have many advantages over bulk alloys, the most obvious of which is cost reduction due to the reduced consumption of precious metal. There are several techniques for producing surface alloys. In this paper the laser irradiation technique is presented. The following lasers: CW CO/sub 2/, Q-switched Nd-YAG, frequency double Q-switched Nd-YAG, and pulsed ruby were used to irradiate and melt thin solid films of precious metals on metal substrates. This causes the surfaces to melt to a depth of approximately 10,000A. Alloying then takes place in the liquid phase where most metals are miscible. The high quench rates obtainable by this method of melting can result in the forming of metastable alloys. This melting and regrowth process is well understood and has been discussed in the literature over the last few years. This paper deals with two binary alloy systems, Au-Ni and Pd-Ti. Surface alloys of Au-Ni with a wide range of concentrations have been produced by laser irradiation of thin Au films on Ni. These films have been analyzed using Rutherford backscattering (RBS) and channeling. Many thin film metals other than Au have also been successfully alloyed using these methods. An example of a potential application is the laser surface alloying of Pd to Ti for corrosion passivation.

  7. Goos-H\\"anchen and Imbert-Fedorov shifts for Gaussian beams impinging on graphene-coated surfaces

    CERN Document Server

    Grosche, Simon; Szameit, Alexander

    2015-01-01

    We present a theoretical study of the Goos-H\\"anchen and Imbert-Fedorov shifts for a fundamental Gaussian beam impinging on a surface coated with a single layer of graphene. We show that the graphene surface conductibility $\\sigma(\\omega)$ is responsible for the appearance of a giant and negative spatial Goos-H\\"anchen shift.

  8. The influence of the segmentation process on 3D measurements from cone beam computed tomography-derived surface models

    NARCIS (Netherlands)

    Engelbrecht, Willem P.; Fourie, Zacharias; Damstra, Janalt; Gerrits, Peter O.; Ren, Yijin

    2013-01-01

    To compare the accuracy of linear and angular measurements between cephalometric and anatomic landmarks on surface models derived from 3D cone beam computed tomography (CBCT) with two different segmentation protocols was the aim of this study. CBCT scans were made of cadaver heads and 3D surface mod

  9. Goos-Hänchen and Imbert-Fedorov shifts for Gaussian beams impinging on graphene-coated surfaces

    Science.gov (United States)

    Grosche, Simon; Ornigotti, Marco; Szameit, Alexander

    2015-11-01

    We present a theoretical study of the Goos-H\\"anchen and Imbert-Fedorov shifts for a fundamental Gaussian beam impinging on a surface coated with a single layer of graphene. We show that the graphene surface conductibility $\\sigma(\\omega)$ is responsible for the appearance of a giant and negative spatial Goos-H\\"anchen shift.

  10. Surface morphology and impurity distribution of electron beam recrystallized silicon films on low cost substrates for solar cell absorber

    Institute of Scientific and Technical Information of China (English)

    FU Li; GROMBALL F; MüLLER J

    2006-01-01

    A line shaped electron beam recrystallised polycrystalline silicon film on the low cost substrate was investigated for the use of the solar cell absorber. The applied EB energy density strongly influences the surface morphology of the film system. Lower EB energy density results in droplet morphology and the rougher SiO2 capping layer due to the low fluidity. With the energy increasing, thecapping layer becomes smooth and continuous and less and small pinholes form in the silicon film. Tungstendisilicide (WSi2) is formed at the interface tungsten/silicon but also at the grain boundaries of the silicon. Because of the fast melting and cooling of the silicon film, the eutectic of silicon and tungstendisilicide mainly forms at the grain boundary of the primary silicon dendrites. The SEM-EDX analysis shows that there are no chlorine and hydrogen in the area surrounding a pinhole after recrystallization because of outgassing during the solidification.

  11. SECTION 6.2 SURFACE TOPOGRAPHY ANALYSIS

    DEFF Research Database (Denmark)

    Seah, M. P.; De Chiffre, Leonardo

    2005-01-01

    Surface physical analysis, i.e. topography characterisation, encompasses measurement, visualisation, and quantification. This is critical for both component form and for surface finish at macro-, micro- and nano-scales. The principal methods of surface topography measurement are stylus profilometry...... representing some average property of the surface under examination. Measurement methods, as well as their application and limitations, are briefly reviewed, including standardisation and traceability issues....

  12. The Simple Lamb Wave Analysis to Characterize Concrete Wide Beams by the Practical MASW Test

    Directory of Open Access Journals (Sweden)

    Young Hak Lee

    2016-06-01

    Full Text Available In recent years, the Lamb wave analysis by the multi-channel analysis of surface waves (MASW for concrete structures has been an effective nondestructive evaluation, such as the condition assessment and dimension identification by the elastic wave velocities and their reflections from boundaries. This study proposes an effective Lamb wave analysis by the practical application of MASW to concrete wide beams in an easy and simple manner in order to identify the dimension and elastic wave velocity (R-wave for the condition assessment (e.g., the estimation of elastic properties. This is done by identifying the zero-order antisymmetric (A0 and first-order symmetric (S1 modes among multimodal Lamb waves. The MASW data were collected on eight concrete wide beams and compared to the actual depth and to the pressure (P- wave velocities collected for the same specimen. Information is extracted from multimodal Lamb wave dispersion curves to obtain the elastic stiffness parameters and the thickness of the concrete structures. Due to the simple and cost-effective procedure associated with the MASW processing technique, the characteristics of several fundamental modes in the experimental Lamb wave dispersion curves could be measured. Available reference data are in good agreement with the parameters that were determined by our analysis scheme.

  13. ANALYSIS FOR BENDING CAPACITY OF REFORCED CONCRETE BEAMS MULTIPLE STRENGTHENED WITH NEAR-SURFACE MOUNTEDCARBON FIBER REINFORCED PLASTIC BAR AND PRE-STRESSED HELICAL RIB BAR%复合内嵌碳纤维筋预应力螺旋肋钢筋加固混凝土梁承载力分析

    Institute of Scientific and Technical Information of China (English)

    任振华; 曾宪桃; 周丰峻

    2012-01-01

    RC beams can be strengthened with Carbon Fiber Reinforced Plastic (CFRP) and pre-stressed Helical Rib Bar ( HRB) that are inserted into the concrete cover of tensile region in the concrete beams , which can effectively improve force performance of the beams . In order to analyze the failure form, ultimate state and normal section bearing capacity of RC beams composites strengthened with near-surface mounted carbon fiber reinforced plastic bar and pre-stressed helical rib bar , the bearing capacity equation of strengthened beams corresponding to different failure modes was supplied by analyzing force in each stage of beams in pre-stress state, bearing capacity calculating and limit state. In order to inspect and verify the rationality and the reliability of the conclusions and the veracity of the equation, the flexural experimental studies were tested on seven concrete beams strengthened with near-surface mounted carbon fiber reinforced plastic bar and pre-stressed helical rib bar. The results indicate that the failure modes and limit state of strengthened beams are reasonable, the equation can veraciously calculate the bend capacity of strengthened beams.%用碳纤维筋和预应力螺旋肋钢筋共同嵌入到混凝土梁受拉区保护层中对混凝土梁进行加固,能更有效地改善混凝土梁的受力性能.为更有效地分析复合内嵌碳纤维筋预应力螺旋肋钢筋加固混凝土梁的破坏形态、极限状态及正截面承载力,通过对预应力状态下梁各阶段受力情况分析、承载力计算及界限状态的判别,提出了加固混凝土梁对应不同破坏形态下承载力的计算公式.为验证所得分析结论的合理性和可靠性及计算公式的准确性,对7根碳纤维筋预应力螺旋肋钢筋加固的混凝土梁进行弯曲试验,结果表明,被加固梁的破坏形态、极限状态分析是合理的,所提出的计算公式能准确计算加固梁抗弯承载能力.

  14. 3D FE Analysis of RC Beams Externally Strengthened with SRG/SRP Systems

    Directory of Open Access Journals (Sweden)

    Francesco Bencardino

    2016-05-01

    Full Text Available The purpose of this study is to evaluate, through a nonlinear Finite Element (FE analysis, the structural behavior of Reinforced Concrete (RC beams externally strengthened by using Steel Reinforced Grout (SRG and Steel Reinforced Polymer (SRP systems. The parameters taken into account were the external strengthening configuration, with or without U-wrap end anchorages, as well as the strengthening materials. The numerical simulations were carried out by using a three-dimensional (3D FE model. The linear and nonlinear behavior of all materials was modeled by appropriate constitutive laws and the connection between concrete substrate and external reinforcing layer was simulated by means of cohesive surfaces with appropriate bond-slip laws. In order to overcome convergence difficulties, to simulate the quasi-static response of the strengthened RC beams, a dynamic approach was adopted. The numerical results in terms of load-displacement curves, failure modes, and load and strain values at critical stages were validated against some experimental data. As a result, the proposed 3D FE model can be used to predict the structural behavior up to ultimate stage of similar strengthened beams without carrying out experimental tests.

  15. Reflection and refraction of narrow Gaussian beams with general astigmatism at tilted optical surfaces: a derivation oriented toward lens design.

    Science.gov (United States)

    Greco, Vincenzo; Giusfredi, Giovanni

    2007-02-01

    The formulas for the reflection and refraction of a narrow Gaussian beam with general astigmatism at a tilted optical surface are derived by ray-tracing techniques. The propagation direction of the reflected and refracted beams is computed by tracing the central ray of the incident beam, and the characteristic parameters of the respective wavefronts are worked out by applying the formulas developed for the generalized ray tracing. Moreover, the Gaussian form of the reflected and refracted amplitude distributions along the transverse coordinates is determined by requiring the matching of the incident, reflected, and refracted light spots on the optical surface. No limiting assumptions are made regarding the form of the optical interface or the orientation of the incident astigmatic wavefront. In the end, to illustrate a simple application of these formulas, the reflection of a Gaussian beam at a conicoid is considered, and a simple property of the conicoidal mirrors is reported.

  16. The analysis of optical wave beams propagation in lens systems

    Science.gov (United States)

    Kazakov, I.; Mosentsov, S.; Moskaletz, O.

    2016-08-01

    In this paper some aspects of the formation and propagation of optical wave beams in lens systems were considered. As an example, the two-lens optical information processing system was considered. Analysis of the two-lens optical circuit has been made with a systems approach perspective. As part of the radio-optical analogies had been applied certain provisions of the theory of dynamical systems to the spatial optical system. The lens system is represented as a simple series-connected optical elements with known spatial impulse response. General impulse response of such a system has been received, as well as consider some special cases of the impulse response. The question of the relationship between the parameters and the size of the input aperture lenses for undistorted transmission of the optical signal has been considered. Analysis of the energy loss resulting from the finite aperture of the lens. It's based on an assessment of the fraction of radiation that propagates beyond the lens. Analysis showed that the energy losses depend explicitly on the following parameters: radiation wavelength, distance between input aperture and lens, and ratio of the input aperture and lens aperture. With the computer help simulation the dependence of losses was shown on the above parameters

  17. Nonparaxial diffraction analysis of Airy and SAiry beams.

    Science.gov (United States)

    Carretero, Luis; Acebal, Pablo; Blaya, Salvador; García, Celia; Fimia, Antonio; Madrigal, Roque; Murciano, Angel

    2009-12-07

    We theoretically analyze Airy beams by solving the exact vectorial Helmholtz equation using boundary conditions at a diffraction aperture. As result, the diffracted beams are obtained in the whole space; thus, we demonstrate that the parabolic trajectories are larger than those previously reported, showing that the Airy beams start to form before the Fourier plane. We also demonstrate the possibility of using a new type of Airy beams (SAiry beams) with finite energy that can be generated at the focal plane of the lens due to diffraction by a circular aperture of a spherical wave modified by a cubic phase. The finite energy ensured by the principle of conservation of energy of a diffracted beam.

  18. Laser Beam Shaping For Lithography on Inclined and Curved Surfaces Using a liquid crystal Spatial Light Modulator

    Science.gov (United States)

    Gatabi, Javad R.; Geerts, Wilhelmus; Tamir, Dan; Pandey, Kumar

    2013-03-01

    An exposure tool for lithography on non-flat substrates that includes a real time photoresist thickness and surface topography monitor is under development at Texas State University. Exposure dose and focusing are corrected on curved parts of the sample using novel laser beam shaping techniques: two approaches using a Holoeye liquid crystal spatial light modulator (LC-SLM) are being investigated: (1) the implementation of multiple lenses with different focal lengths to split the beam into several parts and keeping each part in focus depending on sample topography; (2) the implementation of a tilted lens function resulting in a tilt of the image plane. Image quality is limited by quantization aberration, caused by the phase modulator's bit depth limitation, and pixelation aberration, caused by the modulator's pixel size. A statistical analysis on lenses with different focal lengths provides a detailed description of the mentioned aberrations. The image quality, i.e. resolution and contrast of both techniques, are determined from developed photoresist patterns on curved samples and compared to the theory.

  19. ABCD matrix for reflection and refraction of Gaussian beams at the surface of a parabola of revolution.

    Science.gov (United States)

    Liu, Hongzhan; Liu, Liren; Xu, Rongwei; Luan, Zhu

    2005-08-10

    We report the formulation of an ABCD matrix for reflection and refraction of Gaussian light beams at the surface of a parabola of revolution that separate media of different refractive indices based on optical phase matching. The equations for the spot sizes and wave-front radii of the beams are also obtained by using theABCD matrix. With these matrices, we can more conveniently design and evaluate some special optical systems, including these kinds of elements.

  20. Water accommodation on ice and organic surfaces: insights from environmental molecular beam experiments.

    Science.gov (United States)

    Kong, Xiangrui; Thomson, Erik S; Papagiannakopoulos, Panos; Johansson, Sofia M; Pettersson, Jan B C

    2014-11-26

    Water uptake on aerosol and cloud particles in the atmosphere modifies their chemistry and microphysics with important implications for climate on Earth. Here, we apply an environmental molecular beam (EMB) method to characterize water accommodation on ice and organic surfaces. The adsorption of surface-active compounds including short-chain alcohols, nitric acid, and acetic acid significantly affects accommodation of D2O on ice. n-Hexanol and n-butanol adlayers reduce water uptake by facilitating rapid desorption and function as inefficient barriers for accommodation as well as desorption of water, while the effect of adsorbed methanol is small. Water accommodation is close to unity on nitric-acid- and acetic-acid-covered ice, and accommodation is significantly more efficient than that on the bare ice surface. Water uptake is inefficient on solid alcohols and acetic acid but strongly enhanced on liquid phases including a quasi-liquid layer on solid n-butanol. The EMB method provides unique information on accommodation and rapid kinetics on volatile surfaces, and these studies suggest that adsorbed organic and acidic compounds need to be taken into account when describing water at environmental interfaces.

  1. Surface Nanostructure Formations in an AISI 316L Stainless Steel Induced by Pulsed Electron Beam Treatment

    Directory of Open Access Journals (Sweden)

    Yang Cai

    2015-01-01

    Full Text Available High current pulsed electron beam (HCPEB is an efficient technique for surface modifications of metallic materials. In the present work, the formations of surface nanostructures in an AISI 316L stainless steel induced by direct HCPEB treatment and HCPEB alloying have been investigated. After HCPEB Ti alloying, the sample surface contained a mixture of the ferrite and austenite phases with an average grain size of about 90 nm, because the addition of Ti favors the formation of ferrite. In contrast, electron backscattered diffraction (EBSD analyses revealed no structural refinement on the direct HCPEB treated sample. However, transmission electron microscope (TEM observations showed that fine cells having an average size of 150 nm without misorientations, as well as nanosized carbide particles, were formed in the surface layer after the direct HCPEB treatment. The formation of nanostructures in the 316L stainless steel is therefore attributed to the rapid solidification and the generation of different phases other than the steel substrate in the melted layer.

  2. A study on the die steel surface modification by electron beam

    CERN Document Server

    Wu Ai Min; Zou Jian Xin; Hao Sheng Zhi; Dong Chuang; Zhang Ai Ming; Xu Tao

    2002-01-01

    A new surface modification technology-high current pulsed electron beam treatment method was applied to the surface of die steel to improve its properties. It has been shown that as a result of the HCPEB treatment, the most pronounced changes of the structure-phase state occur in the near-surface layers quenched from the liquid state, where the crystallization front velocity reaches its maximum. In these layers partial or complete dissolving of second phases and formation of over saturated solid solutions and ordered nano-sized structures may take place. This makes it possible to improve substantially the electrochemical and strength properties of the surface layer. The authors found that the thickness of remelt layer is about 10 mu m, and the sectional microhardness increased accompanied by the enhancement of the wear resistance of the material. After modification, the relative wear resistance of D2 steel have increased 5.63 times and that of H13 steel increased 11.76 times

  3. Low-damage surface smoothing of laser crystallized polycrystalline silicon using gas cluster ion beam

    Science.gov (United States)

    Tokioka, H.; Yamarin, H.; Fujino, T.; Inoue, M.; Seki, T.; Matsuo, J.

    2007-04-01

    Surface smoothing of laser crystallized polycrystalline silicon (poly-Si) films using gas cluster ion beam (GCIB) technology has been studied. It is found that both SF6-GCIB and O2-GCIB decrease the height of hillocks and reduce the surface roughness of the irradiated films. The mean surface roughness value of poly-Si films was reduced from 10.8 nm to 2.8 nm by SF6-GCIB irradiation at 80°. Ultraviolet reflectance measurement reveals that GCIB irradiation causes damage near-surface of the poly-Si films. Formation of the damage, however, can be suppressed by using GCIB irradiation at high incident angle. Effect of GCIB irradiation in a metal-insulator-semiconductor (MIS) capacitor has also been investigated. The capacitance-voltage curves of MIS capacitor with SF6-GCIB irradiation are distorted. On the contrary, the distortion is reduced by O2-GCIB irradiation at 80, which suggests that electrical-activated damage of the films can be decreased by using O2-GCIB irradiation.

  4. Analysis of characteristics and applications of electron beam machining

    Institute of Scientific and Technical Information of China (English)

    何宇; 刘军

    2014-01-01

    This paper reveals the great potential of electron beam machining which is high-energy beam machining by describing its principle and characteristics, and shows the feather of electron beam machining through introducing the applications of it in drilling,welding, heat treatment and so on. From two aspects above, its outstanding advantages in machining can be found and a new thought will be given out.

  5. Stability Analysis of Nonlinear Vibrations of a Deploying Flexible Beam

    Institute of Scientific and Technical Information of China (English)

    JunfengLI; ZhaolinWANG

    1996-01-01

    Consider a rigid-flexible coupled system which consists of a central rigid body deploying a flexible appendage,The appendage is modeled as a finite deflection beam having linear constitutive equations.By taking the energy integral as Lyapunov function,it is proved that nonlinear transverse vibrations of the beam undergoing uniform extension or retrieval are stable when there are not controlling moment in the central rigid body and driving force on the beam,according to the partial stablity theorem.

  6. QUASI-STATIC ANALYSIS FOR VISCOELASTIC TIMOSHENKO BEAMS WITH DAMAGE

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on convolution-type constitutive equations for linear viscoelastic materials with damage and the hypotheses of Timoshenko beams, the equations governing quasi-static and dynamical behavior of Timoshenko beams with damage were first derived. The quasi-static behavior of the viscoelastic Timoshenko beam under step loading was analyzed and the analytical solution was obtained in the Laplace transformation domain. The deflection and damage curves at different time were obtained by using the numerical inverse transform and the influences of material parameters on the quasi-static behavior of the beam were investigated in detail.

  7. XPS investigation of ion beam induced conversion of GaAs(0 0 1) surface into GaN overlayer

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Praveen [Surface Physics and Nanostructure Group, National Physical Laboratory, New Delhi 110012 (India); Department of Physics, Indian Institute of Technology, New Delhi 110016 (India); Kumar, Mahesh; Govind [Surface Physics and Nanostructure Group, National Physical Laboratory, New Delhi 110012 (India); Mehta, B.R. [Department of Physics, Indian Institute of Technology, New Delhi 110016 (India); Shivaprasad, S.M., E-mail: smsprasad@jncasr.ac.in [Jawaharlal Nehru Centre for Advanced Scientific Research, International Center for Material Science and Chemistry and Physics Materials Unit, Jakkur, 560064 Bangalore, Karnataka (India)

    2009-10-30

    For the advance of GaN based optoelectronic devices, one of the major barriers has been the high defect density in GaN thin films, due to lattice parameter and thermal expansion incompatibility with conventional substrates. Of late, efforts are focused in fine tuning epitaxial growth and in search for a low temperature method of forming low defect GaN with zincblende structure, by a method compatible to the molecular beam epitaxy process. In principle, to grow zincblende GaN the substrate should have four-fold symmetry and thus zincblende GaN has been prepared on several substrates including Si, 3C-SiC, GaP, MgO, and on GaAs(0 0 1). The iso-structure and a common shared element make the epitaxial growth of GaN on GaAs(0 0 1) feasible and useful. In this study ion-induced conversion of GaAs(0 0 1) surface into GaN at room temperature is optimized. At the outset a Ga-rich surface is formed by Ar{sup +} ion bombardment. Nitrogen ion bombardment of the Ga-rich GaAs surface is performed by using 2-4 keV energy and fluence ranging from 3 x 10{sup 13} ions/cm{sup 2} to 1 x 10{sup 18} ions/cm{sup 2}. Formation of surface GaN is manifested as chemical shift. In situ core level and true secondary electron emission spectra by X-ray photoelectron spectroscopy are monitored to observe the chemical and electronic property changes. Using XPS line shape analysis by deconvolution into chemical state, we report that 3 keV N{sub 2}{sup +} ions and 7.2 x 10{sup 17} ions/cm{sup 2} are the optimal energy and fluence, respectively, for the nitridation of GaAs(0 0 1) surface at room temperature. The measurement of electron emission of the interface shows the dependence of work function to the chemical composition of the interface. Depth profile study by using Ar{sup +} ion sputtering, shows that a stoichiometric GaN of 1 nm thickness forms on the surface. This, room temperature and molecular beam epitaxy compatible, method of forming GaN temperature can serve as an excellent template for

  8. High-resolution proton energy-loss spectrometer for surface analysis

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Noriaki; Kanasaki, Junichi; Matsunami, Noriaki; Matsuda, Kouji; Aoki, Masahiko.

    1988-11-01

    We describe a new ion-beam surface analyzer, proton energy loss spectrometer. It analyzes ions incident at 100 keV and scattered by 180degC at solid surfaces with a resolution of 5eV. The results of computer simulation of the energy spectra of scattered ions and the informations on surface electronic and atomic structures possibly derived by the analysis are described. Application of the spectrometer in several areas of science and technology is briefly discussed.

  9. Coupling of morphology to surface transport in ion-beam-irradiated surfaces: normal incidence and rotating targets

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Garcia, Javier [Grupo Interdisciplinar de Sistemas Complejos (GISC) and School of Mathematical Sciences and Complex and Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4 (Ireland); Cuerno, Rodolfo [Departamento de Matematicas and GISC, Universidad Carlos III de Madrid, Avenida de la Universidad 30, E-28911 Leganes (Spain); Castro, Mario [GISC and Grupo de Dinamica No Lineal (DNL), Escuela Tecnica Superior de IngenierIa (ICAI), Universidad Pontificia Comillas de Madrid, E-28015 Madrid (Spain)], E-mail: javiermunozgarcia@gmail.com, E-mail: cuerno@math.uc3m.es, E-mail: mariocastro73@gmail.com

    2009-06-03

    Continuum models have proved their applicability to describe nanopatterns produced by ion-beam sputtering of amorphous or amorphizable targets at low and medium energies. Here we pursue the recently introduced 'hydrodynamic approach' in the cases of bombardment at normal incidence, or of oblique incidence onto rotating targets, known to lead to self-organized arrangements of nanodots. Our approach stresses the dynamical roles of material (defect) transport at the target surface and of local redeposition. By applying results previously derived for arbitrary angles of incidence, we derive effective evolution equations for these geometries of incidence, which are then numerically studied. Moreover, we show that within our model these equations are identical (albeit with different coefficients) in both cases, provided surface tension is isotropic in the target. We thus account for the common dynamics for both types of incidence conditions, namely formation of dots with short-range order and long-wavelength disorder, and an intermediate coarsening of dot features that improves the local order of the patterns. We provide for the first time approximate analytical predictions for the dependence of stationary dot features (amplitude and wavelength) on phenomenological parameters, that improve upon previous linear estimates. Finally, our theoretical results are discussed in terms of experimental data.

  10. Surface computing and collaborative analysis work

    CERN Document Server

    Brown, Judith; Gossage, Stevenson; Hack, Chris

    2013-01-01

    Large surface computing devices (wall-mounted or tabletop) with touch interfaces and their application to collaborative data analysis, an increasingly important and prevalent activity, is the primary topic of this book. Our goals are to outline the fundamentals of surface computing (a still maturing technology), review relevant work on collaborative data analysis, describe frameworks for understanding collaborative processes, and provide a better understanding of the opportunities for research and development. We describe surfaces as display technologies with which people can interact directly, and emphasize how interaction design changes when designing for large surfaces. We review efforts to use large displays, surfaces or mixed display environments to enable collaborative analytic activity. Collaborative analysis is important in many domains, but to provide concrete examples and a specific focus, we frequently consider analysis work in the security domain, and in particular the challenges security personne...

  11. Surface modifications of hydrogen storage alloy by heavy ion beams with keV to MeV irradiation energies

    Science.gov (United States)

    Abe, Hiroshi; Tokuhira, Shinnosuke; Uchida, Hirohisa; Ohshima, Takeshi

    2015-12-01

    This study deals with the effect of surface modifications induced from keV to MeV heavy ion beams on the initial reaction rate of a hydrogen storage alloy (AB5) in electrochemical process. The rare earth based alloys like this sample alloy are widely used as a negative electrode of Ni-MH (Nickel-Metal Hydride) battery. We aimed to improve the initial reaction rate of hydrogen absorption by effective induction of defects such as vacancies, dislocations, micro-cracks or by addition of atoms into the surface region of the metal alloys. Since defective layer near the surface can easily be oxidized, the conductive oxide layer is formed on the sample surface by O+ beams irradiation, and the conductive oxide layer might cause the improvement of initial reaction rate of hydriding. This paper demonstrates an effective surface treatment of heavy ion irradiation, which induces catalytic activities of rare earth oxides in the alloy surface.

  12. DEVELOPMENT OF ACCELERATOR DATA REPORTING SYSTEM AND ITS APPLICATION TO TREND ANALYSIS OF BEAM CURRENT DATA

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, M.J.; Blokland, W.

    2009-01-01

    Detailed ongoing information about the ion beam quality is crucial to the successful operation of the Spallation Neutron Source at Oak Ridge National Laboratory. In order to provide the highest possible neutron production time, ion beam quality is monitored to isolate possible problems or performance-related issues throughout the accelerator and accumulator ring. For example, beam current monitor (BCM) data is used to determine the quality of the beam transport through the accelerator. In this study, a reporting system infrastructure was implemented and used to generate a trend analysis report of the BCM data. The BCM data was analyzed to facilitate the identifi cation of monitor calibration issues, beam trends, beam abnormalities, beam deviations and overall beam quality. A comparison between transformed BCM report data and accelerator log entries shows promising results which represent correlations between the data and changes made within the accelerator. The BCM analysis report is one of many reports within a system that assist in providing overall beam quality information to facilitate successful beam operation. In future reports, additional data manipulation functions and analysis can be implemented and applied. Built-in and user-defi ned analytic functions are available throughout the reporting system and can be reused with new data.

  13. Sensorial analysis of peanuts processed by e-beam

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Priscila V.; Furgeri, Camilo; Salum, Debora C.; Rogovschi, Vladimir D.; Villavicencio, Anna Lucia C.H. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: villavic@ipen.br

    2007-07-01

    The development of the sensorial analysis was influenced by frequent changes in the technology of production and distribution of foods. Currently the sensorial analysis has represented a decisive part in some sectors of the nourishing industry with the purpose to improve the quality of its products. The food irradiation has as purpose to improve the product quality, in order to eliminate the diverse microorganisms that can spoil the food. The process of irradiation in the recommended doses causes very few chemical alterations in some foods, the nutritional losses are considered insignificant and some of the alterations known found in irradiated foods is not harmful or dangerous. The present study evaluated the sensorial characteristics of peanuts processed by electron beam machine and was made a test of acceptance using a hedonic scale. Samples of peanut had been processed in the doses of 0, 5 and 7 kGy. Thirty volunteer panelists had participated of that acceptance study. The evaluating parameters were: appearance, odor and flavor. The result showed that the consumers had approved the peanut in the dose of 5 and 7 kGy, not having significant difference between the samples controlled and irradiated. (author)

  14. Applications of surface analysis and surface theory in tribology

    Science.gov (United States)

    Ferrante, John

    1989-01-01

    Tribology, the study of adhesion, friction and wear of materials, is a complex field which requires a knowledge of solid state physics, surface physics, chemistry, material science, and mechanical engineering. It has been dominated, however, by the more practical need to make equipment work. With the advent of surface analysis and advances in surface and solid-state theory, a new dimension has been added to the analysis of interactions at tribological interfaces. In this paper the applications of tribological studies and their limitations are presented. Examples from research at the NASA Lewis Research Center are given. Emphasis is on fundamental studies involving the effects of monolayer coverage and thick films on friction and wear. A summary of the current status of theoretical calculations of defect energetics is presented. In addition, some new theoretical techniques which enable simplified quantitative calculations of adhesion, fracture, and friction are discussed.

  15. Formation and characterization of Al-Ti-Nb alloys by electron-beam surface alloying

    Science.gov (United States)

    Valkov, S.; Petrov, P.; Lazarova, R.; Bezdushnyi, R.; Dechev, D.

    2016-12-01

    The combination of attractive mechanical properties, light weight and resistance to corrosion makes Ti-Al based alloys applicable in many industrial branches, like aircraft and automotive industries etc. It is known that the incorporation of Nb improves the high temperature performance and mechanical properties. In the present study on Al substrate Ti and Nb layers were deposited by DC (Direct Current) magnetron sputtering, followed by electron-beam alloying with scanning electron beam. It was chosen two speeds of the specimen motion during the alloying process: V1 = 0.5 cm/s and V2 = 1 cm/s. The alloying process was realized in circular sweep mode in order to maintain the melt pool further. The obtained results demonstrate a formation of (Ti,Nb)Al3 fractions randomly distributed in biphasic structure of intermetallic (Ti,Nb)Al3 particles, dispersed in α-Al solid solution. The evaluated (Ti,Nb)Al3 lattice parameters are independent of the speed of the specimen motion and therefore the alloying speed does not affect the lattice parameters and thus, does not form additional residual stresses, strains etc. It was found that lower velocity of the specimen motion during the alloying process develops more homogeneous structures. The metallographic analyses demonstrate a formation of surface alloys with very high hardness. Our results demonstrate maximal values of 775 HV [kg/cm2] and average hardness of 673 HV [kg/cm2].

  16. Primary Beam and Dish Surface Characterization at the Allen Telescope Array by Radio Holography

    CERN Document Server

    Atkinson, Shannon; Backus, P R; Barott, William; Bauermeister, Amber; Blitz, Leo; Bock, D C -J; Bower, Geoffrey C; Bradford, Tucker; Cheng, Calvin; Croft, Steve; Dexter, Matt; Dreher, John; Engargiola, Greg; Fields, Ed; Heiles, Carl; Helfer, Tamara; Jordan, Jane; Jorgensen, Susan; Kilsdonk, Tom; Gutierrez-Kraybill, Colby; Keating, Garrett; Law, Casey; Lugten, John; MacMahon, D H E; McMahon, Peter; Milgrome, Oren; Siemion, Andrew; Smolek, Ken; Thornton, Douglas; Pierson, Tom; Randall, Karen; Ross, John; Shostak, Seth; Tarter, J C; Urry, Lynn; Werthimer, Dan; Williams, Peter K G; Whysong, David; Harp, G R; Ackermann, R F; Nadler, Z J; Blair, Samantha K; Davis, M M; Wright, M C H; Forster, J R; DeBoer, D R; Welch, W J

    2012-01-01

    The Allen Telescope Array (ATA) is a cm-wave interferometer in California, comprising 42 antenna elements with 6-m diameter dishes. We characterize the antenna optical accuracy using two-antenna interferometry and radio holography. The distortion of each telescope relative to the average is small, with RMS differences of 1 percent of beam peak value. Holography provides images of dish illumination pattern, allowing characterization of as-built mirror surfaces. The ATA dishes can experience mm-scale distortions across -2 meter lengths due to mounting stresses or solar radiation. Experimental RMS errors are 0.7 mm at night and 3 mm under worst case solar illumination. For frequencies 4, 10, and 15 GHz, the nighttime values indicate sensitivity losses of 1, 10 and 20 percent, respectively. The ATA.s exceptional wide-bandwidth permits observations over a continuous range 0.5 to 11.2 GHz, and future retrofits may increase this range to 15 GHz. Beam patterns show a slowly varying focus frequency dependence. We prob...

  17. Fluorescence activated cell sorting via a focused traveling surface acoustic beam.

    Science.gov (United States)

    Ma, Zhichao; Zhou, Yinning; Collins, David J; Ai, Ye

    2017-09-12

    Fluorescence activated cell sorting (FACS) has become an essential technique widely exploited in biological studies and clinical applications. However, current FACS systems are quite complex, expensive, bulky, and pose potential sample contamination and biosafety issues due to the generation of aerosols in an open environment. Microfluidic technology capable of precise cell manipulation has great potential to reinvent and miniaturize conventional FACS systems. In this work, we demonstrate a benchtop scale FACS system that makes use of a highly focused traveling surface acoustic wave beam to sort out micron-sized particles and biological cells upon fluorescence interrogation at ∼kHz rates. The highly focused acoustic wave beam has a width of ∼50 μm that enables highly accurate sorting of individual particles and cells. We have applied our acoustic FACS system to isolate fluorescently labeled MCF-7 breast cancer cells from diluted whole blood samples with the purity of sorted MCF-7 cells higher than 86%. The cell viability before and after acoustic sorting is higher than 95%, indicating excellent biocompatibility that should enable a variety of cell sorting applications in biomedical research.

  18. Recent Developments of Reflectarray Antennas for Reconfigurable Beams Using Surface-Mounted RF-MEMS

    Directory of Open Access Journals (Sweden)

    Eduardo Carrasco

    2012-01-01

    Full Text Available Some of the most recent developments in reconfigurable reflectarrays using surface-mounted RF-MEMS, which have been developed at the Universidad Politécnica de Madrid, are summarized in this paper. The results include reconfigurable elements based on patches aperture-coupled to delay lines in two configurations: single elements and gathered elements which form subarrays with common phase control. The former include traditional aperture-coupled elements and a novel wideband reflectarray element which has been designed using two stacked patches. The latter are proposed as a low cost solution for reducing the number of electronic control devices as well as the manufacturing complexity of large reflectarrays. The main advantages and drawbacks of the grouping are evaluated in both pencil and shaped-beam antennas. In all the cases, the effects of the MEMS switches and their assembly circuitry are evaluated when they are used in a 2-bit phase shifter which can be extended to more bits, demonstrating that the proposed elements can be used efficiently in reconfigurable-beam reflectarrays.

  19. Intracavity contacts for nitride based monolithic surface emitters by focused ion beam processing

    Energy Technology Data Exchange (ETDEWEB)

    Fandrich, Malte; Dartsch, Heiko; Tessarek, Christian; Aschenbrenner, Timo; Hommel, Detlef [Institut fuer Festkoerperphysik - Halbleiterepitaxie, Universitaet Bremen (Germany)

    2010-07-01

    The realization of electrically driven nitride based vertical-cavity surface-emitting lasers (VCSELs) is challenging due to limitations in the conductivity of the distributed Bragg reflectors (DBRs). Therefore monolithic approaches are based on a doped cavity and one or two undoped DBRs. This requires the use of technologically complex intracavity contacts. The presented process yields intracavity contacts applicable to monolithically grown VCSEL structures. Initially mesas are structured by photolithography and chemical assisted ion beam etching. The precise structuring of the prestructured mesas is performed in a focused ion beam system (FIB), where the micropillars are thinned stepwise down to a diameter of 0.5-5 {mu}m. The contacting of the pillars is realized by FIB deposited metal and insulator structures. Insulator separated Pt ring-contacts connect the micropillars with large-scale contact pads. This procedure was applied to a VCSEL structure consisting of a bottom AlInN/GaN-DBR with 40 pairs, a p/n-doped 5 {lambda} GaN-cavity with embedded InGaN quantum dots and a top 10 pair AlInN/GaN-DBR. The developed contacting structure enables a current up to 15 mA through the cavity which documents the capability for the electrical operation of VCSEL devices.

  20. Internal and near-surface electromagnetic fields for a dielectric spheroid illuminated by a zero-order Bessel beam.

    Science.gov (United States)

    Han, Lu; Han, Yiping; Wang, Jiajie; Cui, Zhiwei

    2014-09-01

    Within the framework of generalized Lorenz-Mie theory, scattering from a homogeneous spheroidal particle illuminated by an on-axis zero-order Bessel beam is formulated analytically, with special attention paid to the investigation of internal and near-surface fields. Numerical results concerning the spatial distributions of internal and near-surface fields are presented for various parameter values, such as the half-cone angle of the incident zero-order Bessel beam, the major axis, the minor axis, and the refractive index of the spheroid. The study of internal and near-surface field distributions will contribute to the understanding of Bessel beam scattering by nonspherical particles with sizes close to the incident wavelength.

  1. Microfabrication on Teflon surface by MeV-proton-microbeam and keV-nitrogen-ion-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Akane, E-mail: ogawa.akane@jaea.go.jp [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Satoh, Takahiro; Koka, Masashi [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Kobayashi, Tomohiro [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 350-0198 (Japan); Kamiya, Tomihiro [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

    2013-07-15

    Polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP) are fluoropolymers that have several desirable technological properties, such as electrical insulation and chemical inertness. Nitrogen ion beam irradiation at high fluence forms dense microprotrusions on PTFE and FEP surfaces. Such unique surface structures are useful in cell culture dishes where cells can attach and spread on top of the protrusions. To enhance this functionality, control of surface morphology is necessary. In this study, we create smooth patterns between micro-protrusions by using focused MeV proton beam scanning and subsequent keV nitrogen ion beam irradiation. As a result, many double bonds (C=C) and oxygen-containing groups were detected by attenuated total reflectance/Fourier infrared spectroscopy, particularly in the smooth areas.

  2. Towards a mechanistic analysis of Benkelman beam deflection measurements

    NARCIS (Netherlands)

    Visser, A.F.H.M.; Priambodo Koesrindartono, D.

    2000-01-01

    This paper introduces and describes the Benkelman beam deflection test. Furthermore Benkelman beam tests are simulated using two multi-layer programs, based on an elastic and visco-elastic material model for asphalt. The results of these two programs are compared with each other. Finally, using the

  3. Creating flat-top X-ray beams by applying surface profiles of alternating curvature to deformable piezo bimorph mirrors.

    Science.gov (United States)

    Sutter, John P; Alcock, Simon G; Kashyap, Yogesh; Nistea, Ioana; Wang, Hongchang; Sawhney, Kawal

    2016-11-01

    Beam shaping is becoming increasingly important for synchrotron X-ray applications. Although routine for visible light lasers, this is challenging for X-rays due to the limited source coherence and extreme optical tolerances required for the shaping mirrors. In deliberate defocusing, even surface errors piezo bimorph mirrors permit a continuous range of X-ray beam sizes and shapes. A new theory is developed for applying non-periodic modifications of alternating curvature to optical surfaces. The position and length of the segments may be freely chosen. For the first time, surface modifications of alternating curvature are applied to bimorph mirrors to generate non-Gaussian X-ray beam profiles of specified width. The new theory's freedom is exploited to choose the segments to match the polishing errors of medium wavelength (>10 mm) and the piezos' influence on the mirror's figure. Five- and seven-segment modifications of alternating curvature are calculated and verified by visible light and X-ray metrology. The latter yields beam profiles with less striation than those made by defocusing. Remaining beam striations are explained by applying geometrical optics to the deviations from the ideal surface modifications of alternating curvature.

  4. Ion beam analysis of rubies and their simulants

    Energy Technology Data Exchange (ETDEWEB)

    Juncomma, U. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50202 (Thailand); Intarasiri, S., E-mail: saweat@gmail.com [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50202 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Bootkul, D. [Department of General Science (Gems and Jewelry), Faculty of Science, Srinakharinwirot University, Bangkok 10110 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Tippawan, U., E-mail: beary1001@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50202 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2014-07-15

    Ion beam analysis (IBA) is a set of well known powerful analytical techniques which use energetic particle beam as a probe. Among them, two techniques are suitable for gemological analysis, i.e., Particle Induced X-rays Emission (PIXE) and Ionoluminescence (IL). We combine these two techniques for the investigations of rubies and their simulants. The main objective is to find a reference fingerprint of these gemstones. The data are collected from several natural rubies, synthetic rubies, red spinels, almandine garnets and rubellite which very much resemble and are difficult to distinguish with the gemologist loupe. From our measurements, due to their different crystal structures and compositions, can be clearly distinguished by the IL and PIXE techniques. The results show that the PIXE spectra consist of a few dominant lines of the host matrix elements of each gemstone and some weaker lines due to trace elements of transition metals. PIXE can easily differentiate rubies from other stones by evaluating their chemical compositions. It is noticed that synthetic rubies generally contain fewer impurities, lower iron and higher chromium than the natural ones. Moreover, the IL spectrum of ruby is unique and different from those of others stones. The typical spectrum of ruby is centered at 694 nm, with small sidebands that can be ascribed to a Cr{sup 3+} emission spectrum which is dominated by an R-line at the extreme red end of the visible part of the electromagnetic spectrum. Although the spectrum of synthetic ruby is centered at the same wavelength, the peak is stronger due to higher concentration of Cr and lower concentration of Fe than for natural rubies. For spinel, the IL spectrum shows strong deformation where the R-line is split due to the presence of MgO. For rubellite, the peak center is shifted to 692 nm which might be caused by the replacement of Mn{sup 3+} at the Al{sup 3+} site of the host structure. It is noticed that almandine garnet is not luminescent due

  5. In-situ XMCD evaluation of ferromagnetic state at FeRh thin film surface induced by 1 keV Ar ion beam irradiation and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, T. [Research Organization for the 21st Century, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Aikoh, K. [Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Sakamaki, M.; Amemiya, K. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Iwase, A. [Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan)

    2015-12-15

    Surface ferromagnetic state of FeRh thin films irradiated with 1 keV Ar ion-beam has been investigated by using soft X-ray Magnetic Circular Dichroism (XMCD). It was revealed that the Fe atoms of the samples were strongly spin-polarized after Ar ion-beam irradiation. Due to its small penetration depth, 1 keV Ar ion-beam irradiation can modify the magnetic state at subsurface of the samples. In accordance with the XMCD sum rule analysis, the main component of the irradiation induced ferromagnetism at the FeRh film surface was to be effective spin magnetic moment, and not to be orbital moment. We also confirmed that the surface ferromagnetic state could be produced by thermal annealing of the excessively ion irradiated paramagnetic subsurface of the FeRh thin films. This novel magnetic modification technique by using ion irradiation and subsequent annealing can be a potential tool to control the surface magnetic state of FeRh thin films.

  6. General Analysis of Timoshenko Beams on Elastic Foundation

    Directory of Open Access Journals (Sweden)

    S. Abohadima

    2015-01-01

    Full Text Available General analytical solutions for stability, free and forced vibration of an axially loaded Timoshenko beam resting on a two-parameter foundation subjected to nonuniform lateral excitation are obtained using recursive differentiation method (RDM. Elastic restraints for rotation and translation are assumed at the beam ends to investigate the effect of support weakening on the beam behavior. However, the effects of rotational inertia and shear stress induced from the axial load are considered. The obtained solutions are verified first and then used to investigate the significance of different parameters on the beam behavior. In addition, solutions of forced vibration are analyzed to highlight the effects of excitation nonhomogeneity on the beam behavior.

  7. Surface Impedance Formalism for a Metallic Beam Pipe with Small Corrugations

    Energy Technology Data Exchange (ETDEWEB)

    Stupakov, G.; Bane, K.L.F.; /SLAC

    2012-08-30

    A metallic pipe with wall corrugations is of special interest in light of recent proposals to use such a pipe for the generation of terahertz radiation and for energy dechirping of electron bunches in free electron lasers. In this paper we calculate the surface impedance of a corrugated metal wall and show that it can be reduced to that of a thin layer with dielectric constant {epsilon} and magnetic permeability {mu}. We develop a technique for the calculation of these constants, given the geometrical parameters of the corrugations. We then calculate, for the specific case of a round metallic pipe with small corrugations, the frequency and strength of the resonant mode excited by a relativistic beam. Our analytical results are compared with numerical simulations, and are shown to agree well.

  8. Development of a novel two dimensional surface plasmon resonance sensor using multiplied beam splitting optics.

    Science.gov (United States)

    Hemmi, Akihide; Mizumura, Ryosuke; Kawanishi, Ryuta; Nakajima, Hizuru; Zeng, Hulie; Uchiyama, Katsumi; Kaneki, Noriaki; Imato, Toshihiko

    2013-01-08

    A novel two dimensional surface plasmon resonance (SPR) sensor system with a multi-point sensing region is described. The use of multiplied beam splitting optics, as a core technology, permitted multi-point sensing to be achieved. This system was capable of simultaneously measuring nine sensing points. Calibration curves for sucrose obtained on nine sensing points were linear in the range of 0-10% with a correlation factor of 0.996-0.998 with a relative standard deviation of 0.090-4.0%. The detection limits defined as S/N = 3 were 1.98 × 10(-6) - 3.91 × 10(-5) RIU. This sensitivity is comparable to that of conventional SPR sensors.

  9. Development of a Novel Two Dimensional Surface Plasmon Resonance Sensor Using Multiplied Beam Splitting Optics

    Directory of Open Access Journals (Sweden)

    Akihide Hemmi

    2013-01-01

    Full Text Available A novel two dimensional surface plasmon resonance (SPR sensor system with a multi-point sensing region is described. The use of multiplied beam splitting optics, as a core technology, permitted multi-point sensing to be achieved. This system was capable of simultaneously measuring nine sensing points. Calibration curves for sucrose obtained on nine sensing points were linear in the range of 0–10% with a correlation factor of 0.996–0.998 with a relative standard deviation of 0.090–4.0%. The detection limits defined as S/N = 3 were 1.98 × 10−6–3.91 × 10−5 RIU. This sensitivity is comparable to that of conventional SPR sensors.

  10. Morphology, surface topography and optical studies on electron beam evaporated MgO thin films

    Indian Academy of Sciences (India)

    A Chowdhury; J Kumar

    2006-10-01

    Electron beam evaporated thin films of MgO powder synthesized by burning of magnesium ribbon in air and sol–gel technique are studied for their microstructure (SEM), surface topography (AFM), and optical transmission behaviour (UV-visible spectroscopy). MgO thin films are shown to be either continuous or have mesh like morphology. The bar regions are believed to be of magnesium hydroxide formed due to absorption of moisture. Their AFM images exhibit columnar/pyramidal/truncated cone structure, providing support to the 3D Stranski–Krastanov model for film growth. Further, they are shown to have high transmittance (∼90%) in the wavelength range 400–600 nm, but absorb radiation below 350 nm substantially giving signature of a band transition.

  11. Electron-beam lithography of gold nanostructures for surface-enhanced Raman scattering

    KAUST Repository

    Yue, Weisheng

    2012-10-26

    The fabrication of nanostructured substrates with precisely controlled geometries and arrangements plays an important role in studies of surface-enhanced Raman scattering (SERS). Here, we present two processes based on electron-beam lithography to fabricate gold nanostructures for SERS. One process involves making use of metal lift-off and the other involves the use of the plasma etching. These two processes allow the successful fabrication of gold nanostructures with various kinds of geometrical shapes and different periodic arrangements. 4-mercaptopyridine (4-MPy) and Rhodamine 6G (R6G) molecules are used to probe SERS signals on the nanostructures. The SERS investigations on the nanostructured substrates demonstrate that the gold nanostructured substrates have resulted in large SERS enhancement, which is highly dependent on the geometrical shapes and arrangements of the gold nanostructures. © 2012 IOP Publishing Ltd.

  12. Analysis of active closed cross-section slender beams based on asymptotically correct thin-wall beam theory

    Science.gov (United States)

    Khouli, F.; Langlois, R. G.; Afagh, F. F.

    2007-02-01

    An asymptotically correct theory for multi-cell thin-wall anisotropic slender beams that includes the shell bending strain measures is extended to include embedded active fibre composites (AFCs). A closed-form solution of the asymptotically correct cross-sectional actuation force and moments is obtained. Active thin-wall beam theories found in the literature neglect the shell bending strains, which lead to incorrect predictions for certain cross-sections, while the theory presented is shown to overcome this shortcoming. The theory is implemented and verified against single-cell examples that were solved using the University of Michigan/Variational Beam Sectional Analysis (UM/VABS) software. The stiffness constants and the actuation vector are obtained for two-cell and three-cell active cross-sections. The theory is argued to be reliable for efficient initial design analysis and interdisciplinary parametric or optimization studies of thin-wall closed cross-section slender beams with no initial twist or obliqueness.

  13. Beam reconfigurable antenna for the THz band based on a graphene high impedance surface

    Science.gov (United States)

    Radwan, Ahmed; Verri, Valentina; D'Amico, Michele; Gentili, G. Guido

    2017-01-01

    In this paper a reconfigurable beam antenna is proposed for THz applications, based on a switchable Graphene High Impedance Surface (G-HIS) that acts as a reflector for a primary radiator. The Graphene-HIS structure composed of two layers of graphene cells arranged in a 5×5 array, the two planes of the array are separated by a thin silicon oxide layer; patches in the same row are connected together, to be biased by a common DC voltage to the entire row; this gives the ability to control the graphene conductivity σ. The results show that the shape of the radiation pattern can be changed by changing the voltage applied to each row of G-HIS array. The antenna was fabricated and characterized using a THz-TDS laser system. Measurements are in good agreement with simulations as far as the graphene surface impedance and the resonance frequency are concerned. The scanning reflection on the antenna surface due to the change on the applied voltage is presented to show the effect of biased graphene layer on the dipole properties.

  14. Formation Mechanism of Micropores on the Surface of Pure Aluminum Induced by High-Current Pulsed Electron Beam Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZOU Yang; CAI Jie; WAN Ming-Zhen; LV Peng; GUAN Qing-Feng

    2011-01-01

    The mechanism of micropores formed on the surface of polycrystalline pure aluminum under high-current pulsed electron beam (HCPEB) irradiation is explained. It is discovered that dispersed micropores with sizes of 0.1-1μm on the irradiated surface of pure aluminum can be successfully fabricated after HCPEB irradiation. The dominant formation mechanism of the surface micropores should be attributed to the formation of supersaturation vacancies within the near surface during the HCPEB irradiation and the migration of vacancies along gra,in boundaries and/or dislocations towards the irradiated surface. It is expected that the HCPEB technique will become a new method for the rapid synthesis of surface porous materials.%The mechanism of micropores formed on the surface of polycrystalline pure aluminum under high-current pulsed electron beam (HCPEB) irradiation is explained.It is discovered that dispersed micropores with sizes of 0.1-1μm on the irradiated surface of pure aluminum can be successfully fabricated after HCPEB irradiation.The dominant formation mechanism of the surface micropores should be attributed to the formation of supersaturation vacancies within the near surface during the HCPEB irradiation and the migration of vacancies along grain boundaries and/or dislocations towards the irradiated surface.It is expected that the HCPEB technique will become a new method for the rapid synthesis of surface porous materials.High-current pulsed electron beams (HCPEBs)have attracted much attention in the field of material surface modification.[1-7] During the transient bombardment process a high energy (108-109 W·cm-2) is deposited only in a very thin layer (less than tens of micrometers) within a very short time (a few microseconds) and thereby causes ultrafast heating and cooling on the irradiated surface of materials.The dynamic stress fields induced in these processes can induce intense deformation on the material surface.

  15. Analysis on plastic properties of reactive powder concrete continuous beams reinforced with GFRP bars

    Institute of Scientific and Technical Information of China (English)

    LU Shan-shan; ZHENG Wen-zhong

    2010-01-01

    To study the plastic properties of reactive powder concrete continuous beams reinforced with GFRP bars,the calculation programs for moment redistribution coefficients are prepared by using nonlinear analysis methods such as moment-curvature,conjugate beam method and so on.By comparing the test results of existed FRP bars reinforced concrete continuous beams with simulation results,the accuracy of the calculation program is verified.Then 18 simulated GFRP bars reinforced reactive powder concrete continuous beams are selected whose change parameters are reinforcement ratio of mid-span and middle support.Through the nonlinear analysis of simulated beams,moment redistribution coefficients under mid-span concentrated loads,one-third point loads and uniformly distributed loads are obtained respectively.Thus the formula of moment redistribution coefficients is obtained by fitting moment redistribution coefficients and factors.The results show that the reactive powder concrete continuous beams reinforced with GFRP bars have good plastic properties.

  16. Dividing a light beam into two beams of orthogonal polarizations by reflection and refraction at a dielectric surface.

    Science.gov (United States)

    Azzam, R M A

    2006-05-15

    Reflection and refraction of monochromatic light by an air-dielectric interface at an incidence angle below the Brewster angle can generate split beams of equal power and orthogonal polarizations under certain achievable conditions. Generation of photon streams of orthogonal polarizations, previously thought to be possible mainly by double refraction in anisotropic crystals, is achieved for an infinite set of input states that leads to a correspondingly infinite set of pairs of orthogonal output states. A bare substrate of PbTe is particularly suitable for this beam splitting function in the IR. However, use of a high-refractive-index quarter-wave layer on a low-refractive-index substrate extends the operating range of this interesting device to a much wider spectral range including the visible.

  17. Modification of the titanium alloy surface in electroexplosive alloying with boron carbide and subsequent electron-beam treatment

    Science.gov (United States)

    Gromov, Victor E.; Budovskikh, Evgeniy A.; Ivanov, Yurii F.; Bashchenko, Lyudmila P.; Wang, Xinli; Kobzareva, Tatyana Yu.; Semin, Alexander P.

    2015-10-01

    The modification of the VT6 titanium alloy surface in electroexplosion alloying with plasma being formed in titanium foil with a weighed powder of boron carbide with subsequent irradiation by a pulsed electron beam has been carried out. An electroexplosive alloying zone of a thickness up to 50 μm with a gradient structure is found to form. The subsequent electron-beam treatment of the alloying zone results in smoothing of the alloying surface and is accompanied by the formation of the multilayer structure with alternating layers of various alloying degree at a depth of 30 μm.

  18. Modification of the titanium alloy surface in electroexplosive alloying with boron carbide and subsequent electron-beam treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gromov, Victor E., E-mail: gromov@physics.sibsiu.ru; Budovskikh, Evgeniy A., E-mail: budovskikh-ea@physics.sibsiu.ru; Bashchenko, Lyudmila P., E-mail: gromov@physics.sibsiu.ru; Kobzareva, Tatyana Yu., E-mail: gromov@physics.sibsiu.ru; Semin, Alexander P., E-mail: gromov@physics.sibsiu.ru [Siberian State Industrial University, Novokuznetsk, 654007 (Russian Federation); Ivanov, Yurii F., E-mail: yufi55@mail.ru [Institute of High Current Electronics SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Wang, Xinli, E-mail: wangxl520@hotmail.com [Northeastern University, Liaoning, Shenyang 110819 China (China)

    2015-10-27

    The modification of the VT6 titanium alloy surface in electroexplosion alloying with plasma being formed in titanium foil with a weighed powder of boron carbide with subsequent irradiation by a pulsed electron beam has been carried out. An electroexplosive alloying zone of a thickness up to 50 μm with a gradient structure is found to form. The subsequent electron-beam treatment of the alloying zone results in smoothing of the alloying surface and is accompanied by the formation of the multilayer structure with alternating layers of various alloying degree at a depth of 30 μm.

  19. Free Vibration Analysis of Laminated Composite Beams Using Differential Quadrature Method

    Institute of Scientific and Technical Information of China (English)

    冯丽娟; 钟宏志; 郝照平; 吴德隆

    2002-01-01

    A higher-order theory for laminated composite beams is used to study the free vibration of laminated composite beams, and the differential quadrature method is employed to obtain the numerical solution of the governing differential equations. Free vibration analysis of beams with rectangular cross-section for various combinations of end conditions is studied. The results show that the differential quadrature method is reliable and accurate compared with other available results.

  20. Free Vibration Analysis of a Cross-Ply Laminated Composite Beam on Pasternak Foundation

    OpenAIRE

    R. A. Jafari-Talookolaei; Ahmadian, M. T.

    2007-01-01

    In this study, free vibration analysis of a cross-ply laminated composite beam (LCB) on Pasternak foundation was investigated. Natural frequencies of beam on Pasternak foundation are computed using finite element method (FEM) on the basis of Timoshenko beam theory. Effect of both shear deformation and rotary inertia are implemented in the modeling of stiffness and mass matrices. The model was designed in such a way that it can be used for single-stepped cross-section, stepped foundation and m...

  1. Numerical analysis of sandwich beam with corrugated core under three-point bending

    Energy Technology Data Exchange (ETDEWEB)

    Wittenbeck, Leszek [Poznan University of Technology, Institute of Mathematics Piotrowo Street No. 5, 60-965 Poznan (Poland); Grygorowicz, Magdalena; Paczos, Piotr [Poznan University of Technology, Institute of Applied Mechanics Jana Pawla IIStreet No. 24, 60-965 Poznan (Poland)

    2015-03-10

    The strength problem of sandwich beam with corrugated core under three-point bending is presented.The beam are made of steel and formed by three mutually orthogonal corrugated layers. The finite element analysis (FEA) of the sandwich beam is performed with the use of the FEM system - ABAQUS. The relationship between the applied load and deflection in three-point bending is considered.

  2. Analytical Solution for the Free Vibration Analysis of Delaminated Timoshenko Beams

    OpenAIRE

    2014-01-01

    This work presents a method to find the exact solutions for the free vibration analysis of a delaminated beam based on the Timoshenko type with different boundary conditions. The solutions are obtained by the method of Lagrange multipliers in which the free vibration problem is posed as a constrained variational problem. The Legendre orthogonal polynomials are used as the beam eigenfunctions. Natural frequencies and mode shapes of various Timoshenko beams are presented to demonstrate the effi...

  3. Analytical solution for the free vibration analysis of delaminated Timoshenko beams.

    Science.gov (United States)

    Jafari-Talookolaei, Ramazan-Ali; Abedi, Maryam

    2014-01-01

    This work presents a method to find the exact solutions for the free vibration analysis of a delaminated beam based on the Timoshenko type with different boundary conditions. The solutions are obtained by the method of Lagrange multipliers in which the free vibration problem is posed as a constrained variational problem. The Legendre orthogonal polynomials are used as the beam eigenfunctions. Natural frequencies and mode shapes of various Timoshenko beams are presented to demonstrate the efficiency of the methodology.

  4. A blu-ray laser diode based dual-beam interference lithography for fabrication of diffraction gratings for surface encoders

    Science.gov (United States)

    Zhu, Xiangwen; Li, Xinghui; Zhou, Qian; Wang, Xiaohao; Ni, Kai

    2016-11-01

    The paper presents a dual-beam interference lithography technology for fabrication of diffraction gratings for surface encoders by using cost-effective 405 nm blu-ray laser diodes. In this system, an amplitude division interferometer system is employed. A laser beam raying from a blu-ray laser diode is collimated and then divided into two beams by a beam splitter. These two beams are changed their propagation directions and interfere with each other. Generated interference fringes are exposed on the photoresist coated substrate. Grating line spacing d can be adjusted by changing the incident angle between these two beams. Grating width Wc that determines the measurement of the surface encoder is decided by the coherence length Lc of the laser diode and the grating line spacing d. Calculation and simulation were carried out to decide the grating width. Lc was experimentally obtained. A fabrication system was constructed to verify the feasibility of this technology. Diffraction gratings with a 2.5 micron line spacing and a 2.5 mm width was obtained.

  5. Contact Analysis of Nominally Flat Surfaces

    Science.gov (United States)

    2008-06-01

    specifically surface topography. Starting with the Weierstrass- Mandelbrot Equation (fractal equation), the engineers approximated the power spectrum, and...Komvopoulos, the Weierstrass- Mandelbrot function was used to model the surface topography. A finite element analysis was performed using the commercial... Mandelbrot of Poland. Mandelbrot was the first to point out the feasibility of modeling natural, physical objects with the concept. The property

  6. Development of a novel reaction chamber for ion beam analysis of large samples

    Energy Technology Data Exchange (ETDEWEB)

    Kakuee, O.R. [Van de Graaff Laboratory, Nuclear Science Research School, Nuclear Science and Technology Research Institute (NSTRI), 14395-836 Tehran (Iran, Islamic Republic of)], E-mail: okakuee@yahoo.com; Fathollahi, V.; Agha-Aligol, D.; Farmahini-Farahani, M.; Oliaiy, P.; Lamehi-Rachti, M. [Van de Graaff Laboratory, Nuclear Science Research School, Nuclear Science and Technology Research Institute (NSTRI), 14395-836 Tehran (Iran, Islamic Republic of)

    2008-04-15

    A novel vacuum chamber for ion beam analysis of large-size industrial samples - whose analysis are not feasible in conventional ion beam analysis reaction chambers - has been designed, fabricated and successfully tested. Using the newly developed chamber, both PIXE and RBS analyses could be carried out at the same time and on the same point of the samples. Ion beam analysis using this novel chamber lacks the disadvantages of external beam analysis and benefits the advantages of in-vacuum analysis. This has been achieved by designing a tiny open port in the wall of the reaction chamber to be sealed with a small flat area of sample body where its analysis is of interest. As a case study, two samples of gas turbine blades, a corroded one at highly corrosive environment and a refurbished one after application of certain coatings are analysed using the novel chamber. Experimental results confirm the performance and capability of the reaction chamber.

  7. Wavelet Denoising and Surface Electromyography Analysis

    OpenAIRE

    Hussain, M.S.; Md. Mamun

    2012-01-01

    In this research, Surface Electromyography (SEMG) signal analysis from the right rectus femoris muscle is performed during walk. Wavelet Transform (WT) has been applied for removing noise from the surface SEMG. Gaussianity tests are conducted to understand changes in muscle contraction and to quantify the effectiveness of the noise removal process. Results show that the proposed method can effectively remove noise from the raw SEMG signals for further analysis.

  8. Damage Analysis of Rectangular Section Composite Beam under Pure Bending

    Science.gov (United States)

    Liu, Yiping; Xiao, Fan; Liu, Zejia; Tang, Liqun; Fang, Daining

    2013-02-01

    Laminated composite beams are commonly used in engineering applications involving macro to nano structures. Based on the assumption that plain sections remain plain after deformation, this paper analyzes stress distributions in cross-ply laminated composite beams with rectangular cross-sections, and formulates the basic damage equations through Kachanov's damage definition and Janson's failure criterion. The location of the neutral axis and the ultimate bending moment are obtained for pure bending cases. The effect of the elastic modulus of the two layers on the damage evolution is analyzed; a reasonable damage composite beam model is proposed to predict the ultimate bending moment.

  9. Beam Energy Scaling of Ion-Induced Electron Yield from K+ Ions Impact on Stainless Steel Surfaces

    CERN Document Server

    Kireeff-Covo, Michel; Barnard, John J; Bieniosek, Frank; Celata, C M; Cohen, Ronald; Friedman, Alex; Grote, D P; Kwan, Joe W; Lund, Steven M; Molvik, Arthur; Seidl, Peter; Vay, Jean-Luc; Vujic, Jasmina L; Westenskow, Glen

    2005-01-01

    The cost of accelerators for heavy-ion inertial fusion energy (HIF) can be reduced by using the smallest possible clearance between the beam and the wall from the beamline. This increases beam loss to the walls, generating ion-induced electrons that could be trapped by beam space charge potential into an "electron cloud," which can cause degradation or loss of the ion beam. In order to understand the physical mechanism of production of ion-induced electrons we have measured impact of K+ ions with energies up to 400 KeV on stainless steel surfaces near grazing incidence, using the ion source test stand (STS-500) at LLNL. The electron yield will be discussed and compared with experimental measurements from 1 MeV K+ ions in the High-Current Experiment at LBNL.*

  10. A study of small molecule ingress into planar and cylindrical materials using ion beam analysis

    CERN Document Server

    Smith, R W

    2001-01-01

    mechanisms that take place, and where relevant diffusion coefficients have been obtained using either a semi-infinite medium Fickian planar diffusion model or a cylindrical Fickian diffusion model. Ion beam analysis techniques have been developed to allow profiling of small molecules diffused into materials at depths ranging from 10 sup - sup 7 to 10 sup - sup 1 m. A model DPS/PS/DPS triple-layer film and D( sup 3 He,p) sup 4 He nuclear reaction analysis was used to test the applicability of a novel data processing program - the IBA DataFurnace - to nuclear reaction data. The same reaction and program were used to depth profile the diffusion of heavy water into cellophane. A scanning sup 3 He micro-beam technique was developed to profile the diffusion of small molecules into both planar and cylindrical materials. The materials were exposed to liquids containing deuterium labelled molecules. A cross-section was exposed by cutting the material perpendicular to the surface and this was bombarded by a scanning su...

  11. International Atomic Energy Agency intercomparison of ion beam analysis software

    Science.gov (United States)

    Barradas, N. P.; Arstila, K.; Battistig, G.; Bianconi, M.; Dytlewski, N.; Jeynes, C.; Kótai, E.; Lulli, G.; Mayer, M.; Rauhala, E.; Szilágyi, E.; Thompson, M.

    2007-09-01

    Ion beam analysis (IBA) includes a group of techniques for the determination of elemental concentration depth profiles of thin film materials. Often the final results rely on simulations, fits and calculations, made by dedicated codes written for specific techniques. Here we evaluate numerical codes dedicated to the analysis of Rutherford backscattering spectrometry, non-Rutherford elastic backscattering spectrometry, elastic recoil detection analysis and non-resonant nuclear reaction analysis data. Several software packages have been presented and made available to the community. New codes regularly appear, and old codes continue to be used and occasionally updated and expanded. However, those codes have to date not been validated, or even compared to each other. Consequently, IBA practitioners use codes whose validity, correctness and accuracy have never been validated beyond the authors' efforts. In this work, we present the results of an IBA software intercomparison exercise, where seven different packages participated. These were DEPTH, GISA, DataFurnace (NDF), RBX, RUMP, SIMNRA (all analytical codes) and MCERD (a Monte Carlo code). In a first step, a series of simulations were defined, testing different capabilities of the codes, for fixed conditions. In a second step, a set of real experimental data were analysed. The main conclusion is that the codes perform well within the limits of their design, and that the largest differences in the results obtained are due to differences in the fundamental databases used (stopping power and scattering cross section). In particular, spectra can be calculated including Rutherford cross sections with screening, energy resolution convolutions including energy straggling, and pileup effects, with agreement between the codes available at the 0.1% level. This same agreement is also available for the non-RBS techniques. This agreement is not limited to calculation of spectra from particular structures with predetermined

  12. 0.22 THz wideband sheet electron beam traveling wave tube amplifier: Cold test measurements and beam wave interaction analysis

    Energy Technology Data Exchange (ETDEWEB)

    Baig, Anisullah; Gamzina, Diana; Barchfeld, Robert; Domier, Calvin; Barnett, Larry R.; Luhmann, Neville C. Jr. [Department of Electrical and Computer Engineering, University of California, Davis, California 95616 (United States)

    2012-09-15

    In this paper, we describe micro-fabrication, RF measurements, and particle-in-cell (PIC) simulation modeling analysis of the 0.22 THz double-vane half period staggered traveling wave tube amplifier (TWTA) circuit. The TWTA slow wave structure comprised of two sections separated by two sever ports loaded by loss material, with integrated broadband input/output couplers. The micro-metallic structures were fabricated using nano-CNC milling and diffusion bonded in a three layer process. The 3D optical microscopy and SEM analysis showed that the fabrication error was within 2-3 {mu}m and surface roughness was measured within 30-50 nm. The RF measurements were conducted with an Agilent PNA-X network analyzer employing WR5.1 T/R modules with a frequency range of 178-228 GHz. The in-band insertion loss (S{sub 21}) for both the short section and long section (separated by a sever) was measured as {approx}-5 dB while the return loss was generally around {approx}-15 dB or better. The measurements matched well with the S-matrix simulation analysis that predicted a 3 dB bandwidth of {approx}45 GHz with an operating frequency at 220 GHz. However, the measured S{sub 21} was {approx}3 dB less than the design values, and is attributed to surface roughness and alignment issues. The confirmation measurements were conducted over the full frequency band up to 270 GHz employing a backward wave oscillator (BWO) scalar network analyzer setup employing a BWO in the frequency range 190 GHz-270 GHz. PIC simulations were conducted for the realistic TWT output power performance analysis with incorporation of corner radius of 127 {mu}m, which is inevitably induced by nano-machining. Furthermore, the S{sub 21} value in both sections of the TWT structure was reduced to correspond to the measurements by using a degraded conductivity of 10% International Annealed Copper Standard. At 220 GHz, for an elliptic sheet electron beam of 20 kV and 0.25 A, the average output power of the tube was predicted

  13. Effects of Surface Alloying and Laser Beam Treatment on the Microstructure and Wear Behaviour of Surfaces Modified Using Submerged Metal Arc Welding

    Directory of Open Access Journals (Sweden)

    Regita BENDIKIENE

    2016-05-01

    Full Text Available In this study, the effects of surface alloying of cheap plain carbon steel using submerged metal arc technique and subsequent laser beam treatment on the microstructure and wear behaviour of surfaced layers were studied. This method is the cheapest one to obtain high alloyed coatings, because there is no need to apply complex technologies of powder making (metal powder is spread on the surface of base metal or inserted into the flux, it is enough to grind, granulate and blend additional materials. On the other hand, strengthening of superficial layers of alloys by thermal laser radiation is one of the applications of laser. Surface is strengthened by concentrated laser beam focused into teeny area (from section of mm till some mm. Teeny area of metal heat up rapidly and when heat is drain to the inner metal layers giving strengthening effect. Steel surface during this treatment exceeds critical temperatures, if there is a need to strengthen deeper portions of the base metal it is possible even to fuse superficial layer. The results presented in this paper are based on micro-structural and micro-chemical analyses of the surfaced and laser beam treated surfaces and are supported by analyses of the hardness, the wear resistance and resultant microstructures. Due to the usage of waste raw materials a significant improvement (~ 30 % in wear resistance was achieved. The maximum achieved hardness of surfaced layer was 62 HRC, it can be compared with high alloyed conventional steel grade. Wear properties of overlays with additional laser beam treatment showed that weight loss of these layers was ~10 % lower compared with overlays after welding; consequently it is possible to replace high alloyed conventional steel grades forming new surfaces or restoring worn machine elements and tools.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.7621

  14. Effects of Surface Alloying and Laser Beam Treatment on the Microstructure and Wear Behaviour of Surfaces Modified Using Submerged Metal Arc Welding

    Directory of Open Access Journals (Sweden)

    Regita BENDIKIENE

    2016-05-01

    Full Text Available In this study, the effects of surface alloying of cheap plain carbon steel using submerged metal arc technique and subsequent laser beam treatment on the microstructure and wear behaviour of surfaced layers were studied. This method is the cheapest one to obtain high alloyed coatings, because there is no need to apply complex technologies of powder making (metal powder is spread on the surface of base metal or inserted into the flux, it is enough to grind, granulate and blend additional materials. On the other hand, strengthening of superficial layers of alloys by thermal laser radiation is one of the applications of laser. Surface is strengthened by concentrated laser beam focused into teeny area (from section of mm till some mm. Teeny area of metal heat up rapidly and when heat is drain to the inner metal layers giving strengthening effect. Steel surface during this treatment exceeds critical temperatures, if there is a need to strengthen deeper portions of the base metal it is possible even to fuse superficial layer. The results presented in this paper are based on micro-structural and micro-chemical analyses of the surfaced and laser beam treated surfaces and are supported by analyses of the hardness, the wear resistance and resultant microstructures. Due to the usage of waste raw materials a significant improvement (~ 30 % in wear resistance was achieved. The maximum achieved hardness of surfaced layer was 62 HRC, it can be compared with high alloyed conventional steel grade. Wear properties of overlays with additional laser beam treatment showed that weight loss of these layers was ~10 % lower compared with overlays after welding; consequently it is possible to replace high alloyed conventional steel grades forming new surfaces or restoring worn machine elements and tools.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.7621

  15. Beam positioning stability analysis on large laser facilities

    Institute of Scientific and Technical Information of China (English)

    Fang; Liu; Zhigang; Liu; Liunian; Zheng; Hongbiao; Huang; Jianqiang; Zhu

    2013-01-01

    Beam positioning stability in a laser-driven inertial confinement fusion(ICF) facility is a vital problem that needs to be fixed. Each laser beam in the facility is transmitted in lots of optics for hundreds of meters, and then targeted in a micro-sized pellet to realize controllable fusion. Any turbulence in the environment in such long-distance propagation would affect the displacement of optics and further result in beam focusing and positioning errors. This study concluded that the errors on each of the optics contributed to the target, and it presents an efficient method of enhancing the beam stability by eliminating errors on error-sensitive optics. Optimizations of the optical system and mechanical supporting structures are also presented.

  16. Thermal analysis of the beam missteering in APS storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, I.C.; Howell, J.; Sharma, S.

    1993-08-01

    Several bending magnet beam missteering cases have been investigated for the 7-GeV storage ring of the Advanced Photon Source (APS). One of the critical missteering events is presented in this paper. Finite element analyses are performed to solve for both temperature and stress fields. Thermally induced deflections are determined by using beam bending theory. A safe current limit is established for the storage ring chambers.

  17. Finite element contact analysis of fractal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, Prasanta; Ghosh, Niloy [Department of Mechanical Engineering, Jadavpur University, Kolkata 700032 (India)

    2007-07-21

    The present study considers finite element analysis of non-adhesive, frictionless elastic/elastic-plastic contact between a rigid flat plane and a self-affine fractal rough surface using the commercial finite element package ANSYS. Three-dimensional rough surfaces are generated using a modified two-variable Weierstrass-Mandelbrot function with given fractal parameters. Parametric studies are done to consider the general relations between contact properties and key material and surface parameters. The present analysis is validated with available experimental results in the literature. Non-dimensional contact area and displacement are obtained as functions of non-dimensional load for varying fractal surface parameters in the case of elastic contact and for varying rates of strain hardening in the case of elastic-plastic contact of fractal surfaces.

  18. Integrated Ion Beam Analysis (IBA) in Gunshot Residue (GSR) characterisation.

    Science.gov (United States)

    Romolo, F S; Christopher, M E; Donghi, M; Ripani, L; Jeynes, C; Webb, R P; Ward, N I; Kirkby, K J; Bailey, M J

    2013-09-10

    Gunshot Residue (GSR) is residual material from the discharge of a firearm, which frequently provides crucial information in criminal investigations. Changes in ammunition manufacturing are gradually phasing out the heavy metals on which current forensic GSR analysis is based, and the latest Heavy Metal Free (HMF) primers urgently demand new forensic solutions. Proton scanning microbeam Ion Beam Analysis (IBA), in conjunction with the Scanning Electron Microscope equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDS), can be introduced into forensic analysis to solve both new and old problems, with a procedure entirely commensurate with current forensic practice. Six cartridges producing GSR particles known to be interesting in casework by both experience and the literature were selected for this study. A standard procedure to relocate the same particles previously analysed by SEM-EDS, based on both secondary electron (SE) and X-ray imaging was developed and tested. Elemental Particle Induced X-ray Emission (PIXE) mapping of the emitted X-rays allowed relocation in a scan of 10 μm × 10 μm of even a 1 μm GSR particle. The comparison between spectra from the same particle obtained by SEM-EDS and IBA-PIXE showed that the latter is much more sensitive at mid-high energies. Results that are very interesting in a forensic context were obtained with particles from a cartridge containing mercury fulminate in the primer. Particle-induced gamma-ray emission (PIGE) maps of a particles from HMF cartridges allowed identification of Boron and Sodium in particles from hands using the (10)B(p,α1γ)(7)Be, (11)B(p,p1γ)(11)B and (23)Na(p,p1γ)(23)Na reactions, which is extraordinary in a forensic context. The capability for quantitative analysis of elements within individual particles by IBA was also demonstrated, giving the opportunity to begin a new chapter in the research on GSR particles. The integrated procedure that was developed, which makes use of all the IBA

  19. Analysis of Static and Dynamic Behavior of T-shape Beam Reinforced by External Prestressing Tendon

    Directory of Open Access Journals (Sweden)

    Dinghai Li

    2013-01-01

    Full Text Available External prestressing has become a primary method for strengthening existing concrete beam and has been increasingly used in the construction of newly erected ones, particularly railroad bridges in recent years. In order to evaluate the effect of this method, the static and dynamic behavior of a T-frame beam reinforced by external prestressed strengthened concrete beam was analyzed by 3D finite element method, and the field test study was also made. The study was carried out to further investigate the simply supported reinforced prestressed concrete beam strengthened by external prestressing through theory analysis and experiment.

  20. On the effect of shear coefficients in free vibration analysis of curved beams

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Gon; Lee, Jae Kon; Yoon, Hyun Joong [Catholic University of Daegu, Daegu (Korea, Republic of)

    2014-08-15

    We did a comparative study of shear coefficients in free vibration analysis of curved beams having circular and rectangular cross sections. Until recently, the shear coefficient k in Timoshenko beam theory has been studied by many researchers to include transverse shear deformation effect. To obtain more reliable numerical results, a higher-order hybrid-mixed curved beam element is formulated and programmed in MATLAB. The present numerical experiments show that k = 6(1+v){sup 2}/(7+12v+4v{sup 2}) is the best expression both for circular and rectangular cross-sections in the flexural vibration of curved beams.

  1. Stiffness Analysis of Corrugated Flexure Beam Used in Compliant Mechanisms

    Institute of Scientific and Technical Information of China (English)

    WANG Nianfeng; LIANG Xiaohe; ZHANG Xianmin

    2015-01-01

    Conventional flexible joints generally have limited range of motion and high stress concentration. To overcome these shortcomings, corrugated flexure beam(CF beam) is designed because of its large flexibility obtained from longer overall length on the same span. The successful design of compliant mechanisms using CF beam requires manipulation of the stiffnesses as the design variables. Empirical equations of the CF beam stiffness components, except of the torsional stiffness, are obtained by curve-fitting method. The application ranges of all the parameters in each empirical equation are also discussed. The ratio of off-axis to axial stiffness is considered as a key characteristic of an effective compliant joint. And parameter study shows that the radius of semi-circular segment and the length of straight segment contribute most to the ratio. At last, CF beam is used to design translational and rotational flexible joints, which also verifies the validity of the empirical equations. CF beam with large flexibility is presented, and empirical equations of its stiffness are proposed to facilitate the design of flexible joint with large range of motion.

  2. Quantitative Analysis of Electron Beam Damage in Organic Thin Films.

    Science.gov (United States)

    Leijten, Zino J W A; Keizer, Arthur D A; de With, Gijsbertus; Friedrich, Heiner

    2017-05-18

    In transmission electron microscopy (TEM) the interaction of an electron beam with polymers such as P3HT:PCBM photovoltaic nanocomposites results in electron beam damage, which is the most important factor limiting acquisition of structural or chemical data at high spatial resolution. Beam effects can vary depending on parameters such as electron dose rate, temperature during imaging, and the presence of water and oxygen in the sample. Furthermore, beam damage will occur at different length scales. To assess beam damage at the angstrom scale, we followed the intensity of P3HT and PCBM diffraction rings as a function of accumulated electron dose by acquiring dose series and varying the electron dose rate, sample preparation, and the temperature during acquisition. From this, we calculated a critical dose for diffraction experiments. In imaging mode, thin film deformation was assessed using the normalized cross-correlation coefficient, while mass loss was determined via changes in average intensity and standard deviation, also varying electron dose rate, sample preparation, and temperature during acquisition. The understanding of beam damage and the determination of critical electron doses provides a framework for future experiments to maximize the information content during the acquisition of images and diffraction patterns with (cryogenic) transmission electron microscopy.

  3. Ion Beam Induced Surface Modulations from Nano to Pico: Optimizing Deposition During Erosion and Erosion During Deposition.

    Energy Technology Data Exchange (ETDEWEB)

    MoberlyChan, W J; Schalek, R

    2007-11-08

    Ion beams of sufficient energy to erode a surface can lead to surface modulations that depend on the ion beam, the material surface it impinges, and extrinsic parameters such as temperature and geometric boundary conditions. Focused Ion Beam technology both enables site-specific placement of these modulations and expedites research through fast, high dose and small efficient use of material. The DualBeam (FIB/SEM) enables in situ metrology, with movies observing ripple formation, wave motion, and the influence of line defects. Nanostructures (ripples of >400nm wavelength to dots spaced <40nm) naturally grow from atomically flat surfaces during erosion, however, a steady state size may or may not be achieved as a consequence of numerous controlled parameters: temperature, angle, energy, crystallography. Geometric factors, which can be easily invoked using a FIB, enable a controlled component of deposition (and/or redeposition) to occur during erosion, and conversely allow a component of etching to be incurred during (ion-beam assisted) deposition. High angles of ion beam inclination commonly lead to 'rougher' surfaces, however, the extreme case of 90.0{sup o} etching enables deposition of organized structures 1000 times smaller than the aforementioned, video-recorded nanostructures. Orientation and position of these picostructures (naturally quantized by their atomic spacings) may be controlled by the same parameters as for nanostructures (e.g. ion inclination and imposed boundary conditions, which are flexibly regulated by FIB). Judicious control of angles during FIB-CVD growth stimulates erosion with directionality that produces surface modulations akin to those observed for sputtering. Just as a diamond surface roughens from 1-D ripples to 2-D steps with increasing angle of ion sputtering, so do ripples and steps appear on carbon-grown surfaces with increase in angle of FIB-CVD. Ion beam processing has been a stalwart of the microelectronics industry

  4. Market segmentation and analysis of Japan's residential post and beam construction market.

    Science.gov (United States)

    Joseph A. Roos; Ivan L. Eastin; Hisaaki. Matsuguma

    2005-01-01

    A mail survey of Japanese post and beam builders was conducted to measure their level of ethnocentrism, market orientation, risk aversion, and price consciousness. The data were analyzed utilizing factor and cluster analysis. The results showed that Japanese post and beam builders can be divided into three distinct market segments: open to import...

  5. Capacity Assessment of the Dutch Beam-trawler Fleet using Data Envelopment Analysis

    NARCIS (Netherlands)

    Hoof, van L.J.W.; Wilde, de J.W.

    2005-01-01

    In the framework of a study for the European Commission on 'Measuring Capacity in Fishing Industries using the Data Envelopment Analysis (DEA) Approach,' the methodology was applied to a substantial sample of the Dutch beam trawler fleet. Beam trawling for flatfish is the main occupation of the Dutc

  6. Applications of laser produced ion beams to nuclear analysis of materials

    Science.gov (United States)

    Mima, K.; Azuma, H.; Fujita, K.; Yamazaki, A.; Okuda, C.; Ukyo, Y.; Kato, Y.; Arrabal, R. Gonzalez; Soldo, F.; Perlado, J. M.; Nishimura, H.; Nakai, S.

    2012-07-01

    Laser produced ion beams have unique characteristics which are ultra-short pulse, very low emittance, and variety of nuclear species. These characteristics could be used for analyzing various materials like low Z ion doped heavy metals or ceramics. Energies of laser produced ion beam extend from 0.1MeV to 100MeV. Therefore, various nuclear processes can be induced in the interactions of ion beams with samples. The ion beam driven nuclear analysis has been developed for many years by using various electrostatic accelerators. To explore the applicability of laser ion beam to the analysis of the Li ion battery, a proton beam with the diameter of ˜ 1.0 μm at Takasaki Ion Acceleration for Advanced Radiation Application (TIARA), JAEA was used. For the analysis, the PIGE (Particle-Induced Gamma Ray Emission) is used. The proton beam scans over Li battery electrode samples to diagnose Li density in the LiNi0.85Co0.15O2 anode. As the results, PIGE images for Li area density distributions are obtained with the spatial resolution of better than 1.5μm FWHM. By the Li PIGE images, the depth dependence of de-intercalation levels of Li in the anode is obtained. By the POP experiments at TIARA, it is clarified that laser produced ion beam is appropriate for the Li ion battery analysis. 41.85.Lc, 41.75.Jv, 42.62.cf.

  7. Mathematical modeling and application of removal functions during deterministic ion beam figuring of optical surfaces. Part 2: application.

    Science.gov (United States)

    Liao, Wenlin; Dai, Yifan; Xie, Xuhui; Zhou, Lin

    2014-07-01

    Ion beam figuring (IBF) is established for the final precision figuring of optical components. In this deterministic method, the figuring process is represented by a two-dimensional (2D) convolution operation of a constant removal function and the dwell time, where the figuring precision is guaranteed by the stability of the removal function as well as the solution accuracy of the dwell time. However, the current 2D convolution equation cannot factually reflect the IBF process of curved surfaces, which neglects the influence of the projection distortion and the workpiece geometry. Consequently, the current convolution algorithm for the IBF process would influence the solution accuracy for the dwell time and reduce the convergence of the figuring process. In this part, we propose an improved algorithm based on the mathematical modeling of the dynamic removal function in Part A, which provides a more accurate dwell time for IBF of a curved surface. Additionally, simulation analysis and figuring experiments are carried out to verify the feasibility of our proposed algorithm. The final experimental results indicate that the figuring precision and efficiency can be simultaneously improved by this method.

  8. Finite Element Formulation for Stability and Free Vibration Analysis of Timoshenko Beam

    Directory of Open Access Journals (Sweden)

    Abbas Moallemi-Oreh

    2013-01-01

    Full Text Available A two-node element is suggested for analyzing the stability and free vibration of Timoshenko beam. Cubic displacement polynomial and quadratic rotational fields are selected for this element. Moreover, it is assumed that shear strain of the element has the constant value. Interpolation functions for displacement field and beam rotation are exactly calculated by employing total beam energy and its stationing to shear strain. By exploiting these interpolation functions, beam elements' stiffness matrix is also examined. Furthermore, geometric stiffness matrix and mass matrix of the proposed element are calculated by writing governing equation on stability and beam free vibration. At last, accuracy and efficiency of proposed element are evaluated through numerical tests. These tests show high accuracy of the element in analyzing beam stability and finding its critical load and free vibration analysis.

  9. Nonlinear Analysis of External Prestressed Reinforced Concrete Beams with BFRP and CFRP

    Directory of Open Access Journals (Sweden)

    Haleem K. Hussain

    2017-05-01

    Full Text Available The traditional strengthening methods for concrete structure (girders, beams, columns…. consuming time and could be an economical, a new modern repair methods using the Carbon Fiber Reinforced Polymers (CFRP and Basalt Fiber Reinforced Polymer (BFRP as a laminate strips or bars,and considered a competitive solution that will increase the life-cycle of repaired structures. This study investigated the strengthen reinforced concrete girder. Nonlinear analysis have been adopted to the models using FEM analysis (ANSYS to simulate the theoretical results compared with experimental results.Using finite element packages, more efficient and better analyses can be made to fully understand the response of individual structural components and their contribution to a structure as a whole.Three type of material are used in this study as an external prestressed wire (steel, CFRP and BFRP. The prestressed beam is modeled as simply supported beam with two concentrated point load. The results showed that all tested strengthening beam increased the load carryingcapacity of the beams depend on prestressing force. Obtained Result was compared for different type of beam.This study also was enlarged to include using CFRP and BFRPbarwhich are light weight and moredurable, lead to ease of handling and maintenance. The research conducted analytical work to evaluate the effectiveness of concrete beams reinforced normally by the use of CFRP and BFRP bars. The results showed a significant gain in the beam’s ultimate capacities using CFRP bars comparing with beam reinforced with BFRP bar and reference beam

  10. INDEPENDENT COMPONENT ANALYSIS (ICA) APPLIED TO LONG BUNCH BEAMS IN THE LOS ALAMOS PROTON STORAGE RING

    Energy Technology Data Exchange (ETDEWEB)

    Kolski, Jeffrey S. [Los Alamos National Laboratory; Macek, Robert J. [Los Alamos National Laboratory; McCrady, Rodney C. [Los Alamos National Laboratory; Pang, Xiaoying [Los Alamos National Laboratory

    2012-05-14

    Independent component analysis (ICA) is a powerful blind source separation (BSS) method. Compared to the typical BSS method, principal component analysis (PCA), which is the BSS foundation of the well known model independent analysis (MIA), ICA is more robust to noise, coupling, and nonlinearity. ICA of turn-by-turn beam position data has been used to measure the transverse betatron phase and amplitude functions, dispersion function, linear coupling, sextupole strength, and nonlinear beam dynamics. We apply ICA in a new way to slices along the bunch and discuss the source signals identified as betatron motion and longitudinal beam structure.

  11. Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

    NARCIS (Netherlands)

    Bsat, S.; Yavari, S.; Munsch, M.; Valstar, E.R.; Zadpoor, A.A.

    2015-01-01

    Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bi

  12. Accuracy of linear measurements from cone-beam computed tomography-derived surface models of different voxel sizes

    NARCIS (Netherlands)

    Damstra, Janalt; Fourie, Zacharias; Huddleston Slater, James J R; Ren, Yijin

    2010-01-01

    INTRODUCTION: The aims of this study were to determine the linear accuracy of 3-dimensional surface models derived from a commercially available cone-beam computed tomography (CBCT) dental imaging system and volumetric rendering software and to investigate the influence of voxel resolution on the li

  13. Segmentation process significantly influences the accuracy of 3D surface models derived from cone beam computed tomography

    NARCIS (Netherlands)

    Fourie, Zacharias; Damstra, Janalt; Schepers, Rutger H; Gerrits, Pieter; Ren, Yijin

    2012-01-01

    AIMS: To assess the accuracy of surface models derived from 3D cone beam computed tomography (CBCT) with two different segmentation protocols. MATERIALS AND METHODS: Seven fresh-frozen cadaver heads were used. There was no conflict of interests in this study. CBCT scans were made of the heads and 3D

  14. Accuracy of linear measurements from cone-beam computed tomography-derived surface models of different voxel sizes

    NARCIS (Netherlands)

    Damstra, Janalt; Fourie, Zacharias; Huddleston Slater, James J R; Ren, Yijin

    2010-01-01

    INTRODUCTION: The aims of this study were to determine the linear accuracy of 3-dimensional surface models derived from a commercially available cone-beam computed tomography (CBCT) dental imaging system and volumetric rendering software and to investigate the influence of voxel resolution on the li

  15. Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

    NARCIS (Netherlands)

    Bsat, S.; Yavari, S.; Munsch, M.; Valstar, E.R.; Zadpoor, A.A.

    2015-01-01

    Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be

  16. PHOTOGRAMMETRIC TECHNIQUES FOR ROAD SURFACE ANALYSIS

    Directory of Open Access Journals (Sweden)

    V. A. Knyaz

    2016-06-01

    Full Text Available The quality and condition of a road surface is of great importance for convenience and safety of driving. So the investigations of the behaviour of road materials in laboratory conditions and monitoring of existing roads are widely fulfilled for controlling a geometric parameters and detecting defects in the road surface. Photogrammetry as accurate non-contact measuring method provides powerful means for solving different tasks in road surface reconstruction and analysis. The range of dimensions concerned in road surface analysis can have great variation from tenths of millimetre to hundreds meters and more. So a set of techniques is needed to meet all requirements of road parameters estimation. Two photogrammetric techniques for road surface analysis are presented: for accurate measuring of road pavement and for road surface reconstruction based on imagery obtained from unmanned aerial vehicle. The first technique uses photogrammetric system based on structured light for fast and accurate surface 3D reconstruction and it allows analysing the characteristics of road texture and monitoring the pavement behaviour. The second technique provides dense 3D model road suitable for road macro parameters estimation.

  17. Photogrammetric Techniques for Road Surface Analysis

    Science.gov (United States)

    Knyaz, V. A.; Chibunichev, A. G.

    2016-06-01

    The quality and condition of a road surface is of great importance for convenience and safety of driving. So the investigations of the behaviour of road materials in laboratory conditions and monitoring of existing roads are widely fulfilled for controlling a geometric parameters and detecting defects in the road surface. Photogrammetry as accurate non-contact measuring method provides powerful means for solving different tasks in road surface reconstruction and analysis. The range of dimensions concerned in road surface analysis can have great variation from tenths of millimetre to hundreds meters and more. So a set of techniques is needed to meet all requirements of road parameters estimation. Two photogrammetric techniques for road surface analysis are presented: for accurate measuring of road pavement and for road surface reconstruction based on imagery obtained from unmanned aerial vehicle. The first technique uses photogrammetric system based on structured light for fast and accurate surface 3D reconstruction and it allows analysing the characteristics of road texture and monitoring the pavement behaviour. The second technique provides dense 3D model road suitable for road macro parameters estimation.

  18. Beam-surface scattering studies of the individual and combined effects of VUV radiation and hyperthermal O, O2, or Ar on FEP Teflon surfaces.

    Science.gov (United States)

    Brunsvold, Amy L; Zhang, Jianming; Upadhyaya, Hari P; Minton, Timothy K

    2009-01-01

    Beam-surface scattering experiments were used to probe products that scattered from FEP Teflon surfaces during bombardment by various combinations of atomic and molecular oxygen, Ar atoms, and vacuum ultraviolet (VUV) light. A laser-breakdown source was used to create hyperthermal (translational energies in the range 4-13 eV) beams of argon and atomic/molecular oxygen. The average incidence energy of these beams was tunable and was controlled precisely with a synchronized chopper wheel. A filtered deuterium lamp provided a source of VUV light in a narrow-wavelength range centered at 161 nm. Volatile products that exited the surfaces were monitored with a rotatable mass spectrometer detector. Hyperthermal O atoms with average translational energies above approximately 4 eV may react directly with a pristine FEP Teflon surface, and the reactivity appears to increase with the translational energy of the incident O atoms. VUV light or highly energetic collisions of O2 or Ar may break chemical bonds and lead to the ejection of volatile products; the ejection of volatile products is enhanced when the surface is subjected to VUV light and energetic collisions simultaneously. Exposure to VUV light or to hyperthermal O2 or Ar may increase the reactivity of an FEP Teflon surface to O atoms.

  19. Unified nonlinear analysis for nonhomogeneous anisotropic beams with closed cross sections

    Science.gov (United States)

    Atilgan, Ali R.; Hodges, Dewey H.

    1991-01-01

    A unified methodology for geometrically nonlinear analysis of nonhomogeneous, anisotropic beams is presented. A 2D cross-sectional analysis and a nonlinear 1D global deformation analysis are derived from the common framework of a 3D, geometrically nonlinear theory of elasticity. The only restrictions are that the strain and local rotation are small compared to unity and that warping displacements are small relative to the cross-sectional dimensions. It is concluded that the warping solutions can be affected by large deformation and that this could alter the incremental stiffnes of the section. It is shown that sectional constants derived from the published, linear analysis can be used in the present nonlinear, 1D analysis governing the global deformation of the beam, which is based on intrinsic equations for nonlinear beam behavior. Excellent correlation is obtained with published experimental results for both isotropic and anisotropic beams undergoing large deflections.

  20. Ion beam processing of surfaces and interfaces. Modeling and atomistic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Liedke, Bartosz

    2011-03-24

    Self-organization of regular surface pattern under ion beam erosion was described in detail by Navez in 1962. Several years later in 1986 Bradley and Harper (BH) published the first self-consistent theory on this phenomenon based on the competition of surface roughening described by Sigmund's sputter theory and surface smoothing by Mullins-Herring diffusion. Many papers that followed BH theory introduced other processes responsible for the surface patterning e.g. viscous flow, redeposition, phase separation, preferential sputtering, etc. The present understanding is still not sufficient to specify the dominant driving forces responsible for self-organization. 3D atomistic simulations can improve the understanding by reproducing the pattern formation with the detailed microscopic description of the driving forces. 2D simulations published so far can contribute to this understanding only partially. A novel program package for 3D atomistic simulations called TRIDER (TRansport of Ions in matter with DEfect Relaxation), which unifies full collision cascade simulation with atomistic relaxation processes, has been developed. The collision cascades are provided by simulations based on the Binary Collision Approximation, and the relaxation processes are simulated with the 3D lattice kinetic Monte-Carlo method. This allows, without any phenomenological model, a full 3D atomistic description on experimental spatiotemporal scales. Recently discussed new mechanisms of surface patterning like ballistic mass drift or the dependence of the local morphology on sputtering yield are inherently included in our atomistic approach. The atomistic 3D simulations do not depend so much on experimental assumptions like reported 2D simulations or continuum theories. The 3D computer experiments can even be considered as 'cleanest' possible experiments for checking continuum theories. This work aims mainly at the methodology of a novel atomistic approach, showing that: (i) In

  1. SURFACE ENERGY BALANCE OVER ORANGE ORCHARD USING SURFACE RENEWAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Salvatore Barbagallo

    2009-12-01

    Full Text Available Reliable estimation of surface sensible and latent heat flux is the most important process to appraise energy and mass exchange among atmosphere and biosphere. In this study the surface energy fluxes were measured over an irrigated orange orchard during 2005-2008 monitoring periods using a Surface Renewal- Energy Balance approach. The experimental area is located in a representative orchard growing area of eastern Sicily (Italy. The performance of Surface Renewal (SR analysis for estimating sensible heat flux (H was analysed and evaluated in terms of correlation with H fluxes from the eddy covariance (EC method. Study revealed that the mean available energy (RN- G and latent heat flux (LE were of about 300 W m-2 and 237 W m-2, respectively, during dry periods and unstable-case atmospheric conditions. The estimated crop coefficient Kc values for the orchard crop averaged close to 0.80, which is considerably higher than previous FAO studies that found the value to be 0.65 for citrus with 70% of ground cover. The intercepted photosynthetically active radiation (LI PAR by the crop was measured and relationships between LAI and crop coefficient (Kc were established.

  2. Influence of Surface Coatings of Filler Wires on Weld Seam Properties of Laser Beam Welded Copper Connections

    Science.gov (United States)

    Mann, Vincent; Holzer, Matthias; Hofmann, Konstantin; Özkaya, Esra; Hugger, Florian; Roth, Stephan; Schmidt, Michael

    In laser beam welding of copper its material properties require high intensities of the laser beam for a stable process, which are often realized by small focal diameters. Thus conventional laser beam welding of copper is accompanied by small bridgeable gap widths. A way to increase tolerable gap widths is the use of filler wires, which leads to higher energy consumption per unit length of the process, as extra energy is necessary to melt the filler wire. As some surface coatings are known to reduce energy consumption in laser beam welding of copper, this paper investigates the influence of surface coated filler wires on weld seam properties of laser beam welded of copper alloys with the aim of improved usage of the energy provided for the process. For this reason different coating materials and thicknesses of the filler wires are used within the experiments. The resulting weld seams are evaluated by means of geometrical, electrical and mechanical properties of the joints, e.g. seam width, cross-sectional area, electrical resistance, tensile strength and strain.

  3. Finite element analysis and structural design of pretensioned inverted T-beams with web openings

    Institute of Scientific and Technical Information of China (English)

    Hock Tian CHENG; Bashar S. MOHAMMED; Kamal Nasharuddin MUSTAPHA

    2009-01-01

    This paper presents the results of a research project aimed at providing standard circular web openings to the popular precast pretensioned inverted T-beam.Opening size and placement and required materials strengths were investigated. In this paper the nonlinear analysis and design of simply supported pretensioned inverted T-beam with circular web openings are presented.Two design parameters are varied: opening location and number of openings. The results from nonlinear finite element analysis were substantiated by test results from five pretensioned inverted T-beams with web opening and one solid beam. Good agreement is shown between the theoretical and the experimental results. The test results obtained from this investigation show that the performance of the specimens with web openings is almost identical to that of the specimen without web openings. A simple design method for pretensioned inverted T-beam with

  4. Seismic analysis of the APR1400 nuclear reactor system using a verified beam element model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong-beom [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Park, No-Cheol, E-mail: pnch@yonsei.ac.kr [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Lee, Sang-Jeong; Park, Young-Pil [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Choi, Youngin [Korea Institute of Nuclear Safety, 62 Gwahak-ro, Yuseong-gu, Daejeon 34142 (Korea, Republic of)

    2017-03-15

    Highlights: • A simplified beam element model is constructed based on the real dynamic characteristics of the APR1400. • Time history analysis is performed to calculate the seismic responses of the structures. • Large deformations can be observed at the in-phase mode of reactor vessel and core support barrel. - Abstract: Structural integrity is the first priority in the design of nuclear reactor internal structures. In particular, nuclear reactor internals should be designed to endure external forces, such as those due to earthquakes. Many researchers have performed finite element analyses to meet these design requirements. Generally, a seismic analysis model should reflect the dynamic characteristics of the target system. However, seismic analysis based on the finite element method requires long computation times as well as huge storage space. In this research, a beam element model was developed and confirmed based on the real dynamic characteristics of an advanced pressurized water nuclear reactor 1400 (APR1400) system. That verification process enhances the accuracy of the finite element analysis using the beam elements, remarkably. Also, the beam element model reduces seismic analysis costs. Therefore, the beam element model was used to perform the seismic analysis. Then, the safety of the APR1400 was assessed based on a seismic analysis of the time history responses of its structures. Thus, efficient, accurate seismic analysis was demonstrated using the proposed beam element model.

  5. Analysis of Neutron Production in Passively Scattered Ion-Beam Therapy.

    Science.gov (United States)

    Heo, Seunguk; Yoo, Seunghoon; Song, Yongkeun; Kim, Eunho; Shin, Jaeik; Han, Soorim; Jung, Wongyun; Nam, Sanghee; Lee, Rena; Lee, Kitae; Cho, Sungho

    2017-07-01

    A new treatment facility for heavy ion therapy since 2010 was constructed. In the broad beam, a range shifter, ridge filter and multi leaf collimator (MLC) for the generation of the spread-out Bragg peak is used. In this case, secondary neutrons produced by the interactions of the ion field with beam-modifying devices (e.g. double-scattering system, beam shaping collimators and range compensators) are very important for patient safety. Therefore, these components must be carefully examined in the context of secondary neutron yield and associated secondary cancer risk. In this article, Monte Carlo simulation has been carried out with the FLUktuierende KAskade particle transport code, the fluence and distribution of neutron generation and the neutron dose equivalent from the broad beam components are compared using carbon and proton beams. As a result, it is confirmed that the yield of neutron production using a carbon beam from all components of the broad beam was higher than using a proton beam. The ambient dose by neutrons per heavy ion and proton ion from the MLC surface was 0.12-0.18 and 0.0067-0.0087 pSv, respectively, which shows that heavy ions generate more neutrons than protons. However, ambient dose per treatment 2 Gy, which means physical dose during treatment by ion beam, is higher than carbon beam because proton therapy needs more beam flux to make 2-Gy prescription dose. Therefore, the neutron production from the MLC, which is closed to the patient, is a very important parameter for patient safety. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Post-buckling analysis of composite beams: A simple intuitive formulation

    Indian Academy of Sciences (India)

    Jagadish Babu Gunda; G Venkateswara Rao

    2013-06-01

    Post-buckling analysis of composite beams with axially immovable ends is investigated using an Intuitive formulation. Intuitive formulation uses two parameters namely critical buckling load and axial stretching force developed in the post-buckled domain of composite beam. Geometric nonlinearity of von-Karman type is taken into consideration which accounts for membrane stretching action of the beam. Axial stretching force developed in post-buckled domain of composite beam is evaluated by using an axial governing equation and is expressed either in terms of lateral displacement function as an integrated value, or as a function of both axial and lateral displacement functions at any discrete location of the beam. The available expressions of critical buckling load and derived expressions of axial stretching force developed in the beam are used for obtaining an approximate closed-form expressions for the post-buckling loads of various beam boundary conditions. Numerical accuracy of the proposed analytical closed-form expressions obtained from the intuitive formulation are compared to the available finite element solutions for symmetric and asymmetric lay-up schemes of laminated composite beam. Effect of central amplitude ratio and lay-up orientation on post-buckling load variation is briefly discussed for various beam boundary conditions considered in this study.

  7. An analysis of beam parameters on proton-acoustic waves through an analytic approach.

    Science.gov (United States)

    Aytac Kipergil, Esra; Erkol, Hakan; Kaya, Serhat; Gulsen, Gultekin; Unlu, Mehmet

    2017-03-02

    It has been reported that acoustic waves are generated when a high energy pulsed proton beam is deposited in a small volume within tissue. One possible application of the proton induced acoustics is to get a real-time feedback for intratreatment adjustments by monitoring such acoustic waves. High spatial resolution in ultrasound imaging may reduce proton range uncertainty. Thus, it is crucial to understand the dependence of the acoustic waves on the proton beam characteristics. In this manuscript, firstly, an analytic solution to the proton induced acoustic wave is presented to reveal the dependence of signal on beam parameters, and then combined with an analytic approximation of the Bragg curve. The influence of the beam energy, pulse duration, and beam diameter variation on the acoustic waveform are investigated. Further analysis is performed regarding the Fourier decomposition of proton-acoustic signals. Our results show that smaller spill time of proton beam upsurges the amplitude of acoustic wave for constant number of protons, and hence beneficial for dose monitoring. The increase in the energy of each individual proton in the beam leads to spatial broadening of the Bragg curve, which also yields acoustic waves of greater amplitude. The pulse duration and the beam width of the proton beam do not affect the central frequency of the acoustic wave, but they change the amplitude of the spectral components.

  8. Proceedings (1st) of the Topical Meeting on the Microphysics of Surfaces, Beams, and Adsorbates Held in Santa Fe, New Mexico on 4-6 February 1985.

    Science.gov (United States)

    1985-12-18

    still in the :H. W. K. Tom. C. M. Mate, X. D. Zhu. J. (’ rowell . T F licin. ( infant stage. It is quite obvious that SHG as a surface spec- Somorjai...surfaces " and interesting effects such lar beam. The molecular beam is crossed at right angles by as rotational rainbows and alignment of rotational

  9. Ion-beam modifications of the surface morphology and conductivity in some polymer thin films

    Indian Academy of Sciences (India)

    M Ramakrishna Murthy; E Venkateshwar Rao

    2002-10-01

    Studies on the surface micromorphology and surface conductivity in thin polymer films of poly vinyl alcohol (PVA) and poly ethylene oxide (PEO) in both as-grown and ion-implanted polymer films have been carried out to reveal certain specific features of the ordered state in these materials. Optical microscopic investigations revealed the existence and enhanced formation in number of spherulites and dendrites in ionimplanted films relative to the as-grown films. The number and rate of formation of spherulites indicated an increase in the degree of crystallinity in these films. Measurements of surface conductivity of as-grown and ion-implanted polymer films, employing four-point probe method, indicated a decrease in electrical conductivity on ion-implantation. Photomicrographic analysis of the PVA and PEO thin film surfaces, has enabled to propose a temperature–stress induced mechanism of crystallization in conjunction with the surface conductivity measurements. The decrease in surface conductivity on ion-implantation in both PVA and PEO thin films, is attributed to a decrease in mobility of macromolecular charged species due to an increase in degree of crystallinity as has been observed by optical microscopy.

  10. Analysis of laser beam propagation in a turbulent atmosphere

    Science.gov (United States)

    Clarke, R. H.

    1985-09-01

    The beam propagation method, based on the parabolic approximation to the wave equation, is used in conjunction with Papoulis' redefinition for optical fields of Woodward's ambiguity function. A simple derivation is given of Tatarskii's formula for the lateral coherence function, and hence the mean intensity profile, of a laser beam propagating through a turbulent atmosphere. Statistics of the received signal and the effects of spatial nonstationarity of the turbulence can also be deduced using this technique, as can the effects of very large-scale variations in refractive index and receiver directivity.

  11. Spatial differentiation of Bloch surface wave beams using an on-chip phase-shifted Bragg grating

    Science.gov (United States)

    Doskolovich, L. L.; Bezus, E. A.; Bykov, D. A.; Soifer, V. A.

    2016-11-01

    Bloch surface waves (BSWs) supported by the interfaces between a photonic crystal and a homogeneous medium are considered as a prospective information carrier in integrated photonic circuits. In the present work, we study the application of on-chip phase-shifted Bragg gratings for spatial differentiation of BSW beams. The presented simulation results demonstrate a high accuracy of the performed differentiation. It is shown that upon differentiation of a Gaussian BSW beam, a two-dimensional analogue of the Hermite-Gaussian mode is generated in reflection. The obtained results may find application in the design of new planar devices for analog optical information processing.

  12. Vibration attenuation and shape control of surface mounted, embedded smart beam

    OpenAIRE

    Rathi, Vivek; Khan,Arshad Hussain

    2012-01-01

    Active Vibration Control (AVC) using smart structure is used to reduce the vibration of a system by automatic modification of the system structural response. AVC is widely used, because of its wide and broad frequency response range, low additional mass, high adaptability and good efficiency. A lot of research has been done on Finite Element (FE) models for AVC based on Euler Bernoulli Beam Theory (EBT). In the present work Timoshenko Beam Theory (TBT) is used to model a smart cantilever beam...

  13. Geometrically Nonlinear Static Analysis of Edge Cracked Timoshenko Beams Composed of Functionally Graded Material

    Directory of Open Access Journals (Sweden)

    Şeref Doğuşcan Akbaş

    2013-01-01

    Full Text Available Geometrically nonlinear static analysis of edge cracked cantilever Timoshenko beams composed of functionally graded material (FGM subjected to a nonfollower transversal point load at the free end of the beam is studied with large displacements and large rotations. Material properties of the beam change in the height direction according to exponential distributions. The cracked beam is modeled as an assembly of two subbeams connected through a massless elastic rotational spring. In the study, the finite element of the beam is constructed by using the total Lagrangian Timoshenko beam element approximation. The nonlinear problem is solved by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. The convergence study is performed for various numbers of finite elements. In the study, the effects of the location of crack, the depth of the crack, and various material distributions on the nonlinear static response of the FGM beam are investigated in detail. Also, the difference between the geometrically linear and nonlinear analysis of edge cracked FGM beam is investigated in detail.

  14. Analysis of balance beam deformation in the inertial mass measurement experiment

    Science.gov (United States)

    Fu, Zhuang; Zhang, Zhonghua; Li, Zhengkun; Li, Shisong

    2017-09-01

    This paper provides an analysis of mechanical balance beam deformation in the inertial mass measurement experiment since 2012. The relation between the applied test masses and three types of mechanical elastic deformation of the balance beam, i.e. the changes of rotational inertia, beam length and mass center, are discussed. It is found that changes in the rotational inertia and beam length are high order small quantities of the test mass, and a mechanically optimized balance beam which has good mechanical strength and a light structure is adopted to decrease the influence of the two types of deformation. The mass center change, being proportional to the test mass, has the most impact and can be compensated by a novel mass center compensation approach. Simulations and experiments confirm the effectiveness of the new balance beam and the mass center compensation method. It is emphasized that the analysis of the beam deformation in this paper can also be applied in other experiments where mechanical deformation of the balance beam needs to be considered.

  15. Formation of Ge-Sn nanodots on Si(100 surfaces by molecular beam epitaxy

    Directory of Open Access Journals (Sweden)

    Yu Ing-Song

    2011-01-01

    Full Text Available Abstract The surface morphology of Ge0.96Sn0.04/Si(100 heterostructures grown at temperatures from 250 to 450°C by atomic force microscopy (AFM and scanning tunnel microscopy (STM ex situ has been studied. The statistical data for the density of Ge0.96Sn0.04 nanodots (ND depending on their lateral size have been obtained. Maximum density of ND (6 × 1011 cm-2 with the average lateral size of 7 nm can be obtained at 250°C. Relying on the reflection of high energy electron diffraction, AFM, and STM, it is concluded that molecular beam growth of Ge1-xSnx heterostructures with the small concentrations of Sn in the range of substrate temperatures from 250 to 450°C follows the Stranski-Krastanow mechanism. Based on the technique of recording diffractometry of high energy electrons during the process of epitaxy, the wetting layer thickness of Ge0.96Sn0.04 films is found to depend on the temperature of the substrate.

  16. Fabrication of hydrophobic structures on coronary stent surface based on direct three-beam laser interference lithography

    Science.gov (United States)

    Gao, Long-yue; Zhou, Wei-qi; Wang, Yuan-bo; Wang, Si-qi; Bai, Chong; Li, Shi-ming; Liu, Bin; Wang, Jun-nan; Cui, Cheng-kun; Li, Yong-liang

    2016-05-01

    To solve the problems with coronary stent implantation, coronary artery stent surface was directly modified by three-beam laser interference lithography through imitating the water-repellent surface of lotus leaf, and uniform micro-nano structures with the controllable period were fabricated. The morphological properties and contact angle (CA) of the microstructure were measured by scanning electron microscope (SEM) and CA system. The water repellency of stent was also evaluated by the contact and then separation between the water drop and the stent. The results show that the close-packed concave structure with the period of about 12 μm can be fabricated on the stent surface with special parameters (incident angle of 3°, laser energy density of 2.2 J·cm-2 and exposure time of 80 s) by using the three-beam laser at 1 064 nm, and the structure has good water repellency with CA of 120°.

  17. Note: Ion-induced secondary electron emission from oxidized metal surfaces measured in a particle beam reactor

    Science.gov (United States)

    Marcak, Adrian; Corbella, Carles; de los Arcos, Teresa; von Keudell, Achim

    2015-10-01

    The secondary electron emission of metals induced by slow ions is characterized in a beam chamber by means of two coaxial semi-cylindrical electrodes with different apertures. The voltages of the outer electrode (screening), inner electrode (collector), and sample holder (target) were set independently in order to measure the effective yield of potential and kinetic electron emissions during ion bombardment. Aluminum samples were exposed to quantified beams of argon ions up to 2000 eV and to oxygen atoms and molecules in order to mimic the plasma-surface interactions on metallic targets during reactive sputtering. The variation of electron emission yield was correlated to the ion energy and to the oxidation state of Al surfaces. This system provides reliable measurements of the electron yields in real time and is of great utility to explore the fundamental surface processes during target poisoning occurring in reactive magnetron sputtering applications.

  18. Note: Ion-induced secondary electron emission from oxidized metal surfaces measured in a particle beam reactor

    Energy Technology Data Exchange (ETDEWEB)

    Marcak, Adrian; Corbella, Carles, E-mail: carles.corbella@rub.de; Keudell, Achim von [Research Group Reactive Plasmas, Ruhr-University Bochum, 44801 Bochum (Germany); Arcos, Teresa de los [Technical and Macromolecular Chemistry, Paderborn University, 33098 Paderborn (Germany)

    2015-10-15

    The secondary electron emission of metals induced by slow ions is characterized in a beam chamber by means of two coaxial semi-cylindrical electrodes with different apertures. The voltages of the outer electrode (screening), inner electrode (collector), and sample holder (target) were set independently in order to measure the effective yield of potential and kinetic electron emissions during ion bombardment. Aluminum samples were exposed to quantified beams of argon ions up to 2000 eV and to oxygen atoms and molecules in order to mimic the plasma-surface interactions on metallic targets during reactive sputtering. The variation of electron emission yield was correlated to the ion energy and to the oxidation state of Al surfaces. This system provides reliable measurements of the electron yields in real time and is of great utility to explore the fundamental surface processes during target poisoning occurring in reactive magnetron sputtering applications.

  19. Novel fabry-pérot cavity antenna with enhanced beam steering property using reconfigurable meta-surface

    Science.gov (United States)

    Xie, Peng; Wang, Guangming; Cai, Tong; Li, Haipeng; Liang, Jiangang

    2017-07-01

    Fabry-Pérot cavity (FPC) antenna is essential and widely used in communication system. However, conventional Fabry-Pérot cavity antennas suffer from limited working modes, small beam steering range, and also complex configurations. Here, we propose a novel reconfigurable meta-surface to extend the working modes of the FPC antenna, and thus enhanced beam steering angles (-54° to 54°). The reconfigurable meta-surface consists of 6 × 6 unit cells, occupying an area of 90 mm × 90 mm. The well-designed bias circuits can control the reflection phase of the meta-surface by tuning the states of the inserted PIN diodes, which results in 11 radiation directions of our FPC antenna. For experimental demonstration, we fabricate and assemble an antenna sample working at 5 GHz. Numerical and experimental results coincide well with each other, indicating enhanced radiation properties and wide applications of our FPC antenna.

  20. Novel microstructural growth in the surface of Inconel 625 by the addition of SiC under electron beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, M., E-mail: maqomer@yahoo.com [Physics Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), P.O. Nilore, Islamabad (Pakistan); Ali, G.; Ahmed, Ejaz; Haq, M.A.; Akhter, J.I. [Physics Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), P.O. Nilore, Islamabad (Pakistan)

    2011-06-15

    Electron beam melting is being used to modify the microstructure of the surfaces of materials due to its ability to cause localized melting and supercooling of the melt. This article presents an experimental study on the surface modification of Ni-based superalloy (Inconel 625) reinforced with SiC ceramic particles under electron beam melting. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction techniques have been applied to characterize the resulted microstructure. The results revealed growth of novel structures like wire, rod, tubular, pyramid, bamboo and tweezers type morphologies in the modified surface. In addition to that fibrous like structure was also observed. Formation of thin carbon sheet has been found at the regions of decomposed SiC. Electron beam modified surface of Inconel 625 alloy has been hardened twice as compared to the as-received samples. Surface hardening effect may be attributed to both the formation of the novel structures as well as the introduction of Si and C atom in the lattice of Inconel 625 alloy.

  1. Beam formation in CERNs cesiated surfaces and volume H- ion sources

    Science.gov (United States)

    Mochalskyy, Serhiy; Lettry, Jacques; Minea, Tiberiu

    2016-08-01

    At CERN, a high performance negative ion (NI) source is required for the 160 MeV H- linear accelerator named Linac4. The source should deliver 80 mA H- ion beams within an emittance of 0.25 mm·mrad. For this purpose two ion sources were developed: IS01 is based on the NI volume production and IS02 provides additional NI by surface production via H interaction on a cesiated Molybdenum plasma electrode. The development of negative ion sources for Linac4 is accompanied by modelling activities. ONIX code has been modified and adapted to investigate the transport of NI and electrons in the extraction region of the CERN negative ion sources. The simulated results from modeling of IS01 and IS02 extraction regions, which were obtained in 2012 during source commissioning, are presented and benchmarked with experimental measurements obtained after 2013. The formation of the plasma meniscus and the screening of the extraction field by the source plasma are discussed. The NI production is compared between two types of sources, the first one based on volume production only and the second one encompassing NI cesiated surface production. For the IS02 source, different states of conditioning were simulated by changing the NI emission flux from the plasma electrode and Cs+ density in the bulk plasma region. The numerical results show that in low work function regime, with high NI surface emission rate of 3000 A m-2 and Cs-density of nCs+ = 3.8 × 1016 m-3, the total extracted NI current could reach ~80 mA. At the less favorable Cs-coverage, when the surface NI emission rate becomes significantly lower, namely 300 A m-2 with nCs+ = 3.3 × 1015 m-3, the total extracted NI current only reaches ~20 mA. A good agreement between simulation and experimental results is observed in terms of extracted NI current for both extraction systems, including the case of reversed extraction potential that corresponds to positive (H+) ion extraction.

  2. Electron beam pumped III-V nitride vertical cavity surface emitting lasers grown by molecular beam epitaxy

    Science.gov (United States)

    Ng, Hock Min

    The design and fabrication by molecular beam epitaxy of a prototype vertical cavity laser based on the III-V nitrides were investigated in this work. The bottom mirror of the laser consists of distributed Bragg reflectors (DBRs) based on quarterwave AlN (or AlxGa1-xN) and GaN layers. Such DBRs were designed for maximum reflectivity in the spectral region from 390--600 nm. The epitaxial growth of these two binaries on each other revealed that while AlN grows on GaN in a two-dimensional mode (Frank-van der Merwe mode), GaN grows on AlN in a three-dimensional mode (Stranski-Krastanov mode). In spite of that, DBRs with peak reflectance up to 99% and bandwidths of 45nm were fabricated. The measured reflectance spectra were compared with simulations using the transmission matrix method. The mechanical stability of these DBR structures due to non-uniform distribution of strain arising from lattice or thermal mismatch of the various components were also addressed. The active region of the laser consists of InGaN/GaN multiple quantum wells (MQWs). The existence of up to the third order diffraction peaks in the x-ray diffraction spectra suggests that the interfaces between InGaN and GaN are sharp with little interdiffusion at the growth temperature. The photoluminescence and cathodoluminescence spectra were analyzed to determine the optical quality of the MQWs. The best MQWs were shown to have a single emission peak at 397nm with full width half maximum (FWHM) of 11nm. Cathodoluminescence studies showed that there are spatially localized areas of intense light emission. The complete device was formed on (0001) sapphire substrates using the previously described DBRs as bottom mirrors and the MQWs as the active region. The top mirror of the device consists of metallic silver. The device was pumped by an electron beam from the top mirror side and the light output was collected from the sapphire side. Measurements at 100K showed narrowing of the linewidth with increasing pump

  3. Reliability analysis of beams on random elastic foundations

    NARCIS (Netherlands)

    Griffiths, D.V.; Paiboon, J.; Huang, J.; Fenton, G.A.

    2012-01-01

    The classical problem of a beam on an elastic foundation has long been of practical interest to geotechnical engineers, because it provides a framework for computing deflections not only of foundations, but also of vertically oriented laterally loaded piles. The supporting soil can be modelled as an

  4. Laser Brazing with Beam Scanning: Experimental and Simulative Analysis

    Science.gov (United States)

    Heitmanek, M.; Dobler, M.; Graudenz, M.; Perret, W.; Göbel, G.; Schmidt, M.; Beyer, E.

    Laser beam brazing with copper based filler wire is a widely established technology for joining zinc-coated steel plates in the body-shop. Successful applications are the divided tailgate or the zero-gap joint, which represents the joint between the side panel and the roof-top of the body-in-white. These joints are in direct view to the customer, and therefore have to fulfil highest optical quality requirements. For this reason a stable and efficient laser brazing process is essential. In this paper the current results on quality improvement due to one dimensional laser beam deflections in feed direction are presented. Additionally to the experimental results a transient three-dimensional simulation model for the laser beam brazing process is taken into account. With this model the influence of scanning parameters on filler wire temperature and melt pool characteristics is analyzed. The theoretical predictions are in good accordance with the experimental results. They show that the beam scanning approach is a very promising method to increase process stability and seam quality.

  5. Numerical analysis of reinforced concrete continuous deep beams

    NARCIS (Netherlands)

    Asin, M.; Walraven, J.

    1995-01-01

    The structural behaviour of deep beams is still not completely understood, since, for example, plane sections do not remain plane and no uniform shear flow can develop because of the small ratio between depth and shear span. If in addition, the supporting system is also statically indeterminate, the

  6. Numerical analysis of reinforced concrete continuous deep beams

    NARCIS (Netherlands)

    Asin, M.; Walraven, J.

    1995-01-01

    The structural behaviour of deep beams is still not completely understood, since, for example, plane sections do not remain plane and no uniform shear flow can develop because of the small ratio between depth and shear span. If in addition, the supporting system is also statically indeterminate, the

  7. BEAMS: separating the wheat from the chaff in supernova analysis

    CERN Document Server

    Kunz, Martin; Bassett, Bruce A; Smith, Mathew; Newling, James; Varughese, Melvin

    2012-01-01

    We introduce Bayesian Estimation Applied to Multiple Species (BEAMS), an algorithm designed to deal with parameter estimation when using contaminated data. We present the algorithm and demonstrate how it works with the help of a Gaussian simulation. We then apply it to supernova data from the Sloan Digital Sky Survey (SDSS), showing how the resulting confidence contours of the cosmological parameters shrink significantly.

  8. Positron beam analysis of polymer/metal interfaces under stress

    NARCIS (Netherlands)

    Galindo, RE; van Veen, A; Garcia, AA; Schut, H; De Hosson, JTM; Triftshauser, W; Kogel, G; Sperr, P

    2001-01-01

    The polymers Epoxy and Poly(Methyl MethAcrylate) spin coated on Interstitial Free (IF) steel were subjected to external stresses and studied using the Delft Variable Energy Positron (VEP) beam facility. The polymer/metal interface was identified using an S-W map. After tensile experiments vacancy fo

  9. Comparative analysis between mandibular positions in centric relation and maximum intercuspation by cone beam computed tomography (CONE-BEAM).

    Science.gov (United States)

    Ferreira, Amanda de Freitas; Henriques, João César Guimarães; Almeida, Guilherme Araújo; Machado, Asbel Rodrigues; Machado, Naila Aparecida de Godoi; Fernandes Neto, Alfredo Júlio

    2009-01-01

    This research consisted of a quantitative assessment, and aimed to measure the possible discrepancies between the maxillomandibular positions for centric relation (CR) and maximum intercuspation (MI), using computed tomography volumetric cone beam (cone beam method). The sample of the study consisted of 10 asymptomatic young adult patients divided into two types of standard occlusion: normal occlusion and Angle Class I occlusion. In order to obtain the centric relation, a JIG device and mandible manipulation were used to deprogram the habitual conditions of the jaw. The evaluations were conducted in both frontal and lateral tomographic images, showing the condyle/articular fossa relation. The images were processed in the software included in the NewTom 3G device (QR NNT software version 2.00), and 8 tomographic images were obtained per patient, four laterally and four frontally exhibiting the TMA's (in CR and MI, on both sides, right and left). By means of tools included in another software, linear and angular measurements were performed and statistically analyzed by student t test. According to the methodology and the analysis performed in asymptomatic patients, it was not possible to detect statistically significant differences between the positions of centric relation and maximum intercuspation. However, the resources of cone beam tomography are of extreme relevance to the completion of further studies that use heterogeneous groups of samples in order to compare the results.

  10. Comparative analysis between mandibular positions in centric relation and maximum intercuspation by cone beam computed tomography (CONE-BEAM

    Directory of Open Access Journals (Sweden)

    Amanda de Freitas Ferreira

    2009-01-01

    Full Text Available This research consisted of a quantitative assessment, and aimed to measure the possible discrepancies between the maxillomandibular positions for centric relation (CR and maximum intercuspation (MI, using computed tomography volumetric cone beam (cone beam method. The sample of the study consisted of 10 asymptomatic young adult patients divided into two types of standard occlusion: normal occlusion and Angle Class I occlusion. In order to obtain the centric relation, a JIG device and mandible manipulation were used to deprogram the habitual conditions of the jaw. The evaluations were conducted in both frontal and lateral tomographic images, showing the condyle/articular fossa relation. The images were processed in the software included in the NewTom 3G device (QR NNT software version 2.00, and 8 tomographic images were obtained per patient, four laterally and four frontally exhibiting the TMA's (in CR and MI, on both sides, right and left. By means of tools included in another software, linear and angular measurements were performed and statistically analyzed by student t test. According to the methodology and the analysis performed in asymptomatic patients, it was not possible to detect statistically significant differences between the positions of centric relation and maximum intercuspation. However, the resources of cone beam tomography are of extreme relevance to the completion of further studies that use heterogeneous groups of samples in order to compare the results.

  11. XRF Experiment for Elementary Surface Analysis

    Science.gov (United States)

    Köhler, E.; Dreißigacker, A.; Fabel, O.; van Gasselt, S.; Meyer, M.

    2014-04-01

    The proposed X-Ray Fluorescence Instrument Package (XRF-X and XRF-E) is being designed to quantitatively measure the composition and map the distribution of rock-surface materials in order to support the target area selection process for exploration, sampling, and mining. While energydispersive X-Ray fluorescence (EDX) makes use of Solar X-Rays for excitation to probe materials over arbitrary distances (by XRF-X), electron-beam excitation can be used for proximity measurements (by XRF-E) over short-distance of up to about 10 - 20m. This design is targeted at observing and analyzing surface compositions from orbital platforms and it is in particular applicable to all atmosphereless solidsurface bodies. While the instrument design for observing objects in the outer solar system is challenging due to low count rates, the Moon and objects of the asteroid belt usually receive solar X-ray radiation that allows to integrate a statistically reliable data basis. Asteroids are attractive targets and have been visited using X-ray fluorescence instruments by orbiting spacecraft in the past (Itokawa, Eros). They are wellaccessible objects for determining elemental compositions and assessing potential mineral resources.

  12. Nanostructure Formations and Improvement in Corrosion Resistance of Steels by Means of Pulsed Electron Beam Surface Treatment

    Directory of Open Access Journals (Sweden)

    K. M. Zhang

    2013-01-01

    Full Text Available The corrosion of steels has long been the topic for materials scientists. It is established that surface treatment is an efficient way to improve the corrosion resistance of steels without changing the bulk properties and with low costs. In the present paper, different kinds of surface treatment techniques for steels are briefly reviewed. In particular, the surface modification involving nanostructure formations of steels by using a low energy high pulsed electron beam (LEHCPEB treatment is lightened in the case of an AISI 316L stainless steel and D2 steel. The overall results demonstrate the high potential of the LEHCPEB technique for improving the corrosion performance of steels.

  13. Standardization of surface contamination analysis systems

    Science.gov (United States)

    Boothe, Richard E.

    1995-01-01

    Corrosion products, oils and greases can potentially degrade material bonding properties. The Marshall Space Flight Center (MSFC) Surface Contamination Analysis Team (SCAT) utilizes a variety of analytical equipment to detect identify and quantify contamination on metallic and non-metallic substrates. Analysis techniques include FT-IR Microscopy (FT-IR), Near Infrared Optical Fiber Spectrometry (NIR), Optically Stimulated Electron Emission (OSEE), Ultraviolet Fluorescence (UVF) and Ellipsometry. To insure that consistent qualitative and quantitative information are obtained, standards are required to develop analysis techniques, to establish instrument sensitivity to potential contaminants, and to develop calibration curves. This paper describes techniques for preparing and preserving contamination standards. Calibration of surface contamination analysis systems is discussed, and methods are presented for evaluating the effects of potential contaminants on bonding properties.

  14. The effect of CH4/H2 ratio on the surface properties of HDPE treated by CHx ion beam bombardment

    Science.gov (United States)

    Ding, Wanyu; Guo, Yuanyuan; Ju, Dongying; Sato, Susumu; Tsunoda, Teruo

    2016-06-01

    The surface of high density polyethylene (HDPE) substrate was bombarded by the CHx group ion beam, which was generated by the mixture of CH4/H2. Varying the CH4/H2 ratio, HDPE surfaces with different chemical bond structures and properties were obtained. Raman and XPS results show that sp2 and sp3 bond structures are formed at HDPE surface bombarded by CHx group ions. The sp3 bond fraction at bombarded HDPE surface depends on the H2 ratio in CH4/H2 mixture, because the H ion/atom/molecule can improve the growth of sp3 bond structure. For HDPE surface bombarded by CH4/H2 = 50/50, sp3 bond fraction reaches the maximum of 30.5%, the surface roughness decreases to 17.04 nm, and the static contact angle of polar H2O molecule increased to 140.2∘.

  15. Vibration Analysis of Randomly Oriented Carbon Nanotube Based on FGM Beam Using Timoshenko Theory

    Directory of Open Access Journals (Sweden)

    Mohammad Amin Rashidifar

    2015-02-01

    Full Text Available The carbon nanotube (CNT reinforced functionally graded materials (FGM are expected to be the new generation materials having wide range of unexplored potential applications in various technological areas such as aerospace and structural and chemical industry. The present work deals with the finite element modeling and free vibration analysis of CNT based functionally graded beam using three-dimensional Timoshenko beam theory. It has been assumed that the material properties of CNT based FG beam vary only along the thickness and these properties are evaluated by rule of mixture. The extended Hamilton principle has been applied to find out the governing equations of CNT based FG beam. Finite element method is used to solve governing equation with the exact shape functions. Initial analysis deals with CNTs assumed to be oriented along the length direction only. But practically it is not possible. So, further work deals with the free vibration analysis of functionally graded nanocomposite beams reinforced by randomly oriented straight single walled carbon nanotubes (SWCNTs. The Eshelby-Mori-Tanaka approach based on an equivalent fiber is used to investigate the material properties of the beam. Results are presented in tabular and graphical forms to show the effects of carbon nanotube orientations, slenderness ratios, and boundary conditions on the dynamic behavior of the beam.

  16. 6D phase space electron beam analysis and machine sensitivity studies for ELI-NP GBS

    Science.gov (United States)

    Giribono, A.; Bacci, A.; Curatolo, C.; Drebot, I.; Palumbo, L.; Petrillo, V.; Rossi, A. R.; Serafini, L.; Vaccarezza, C.; Vannozzi, A.; Variola, A.

    2016-09-01

    The ELI-NP Gamma Beam Source (GBS) is now under construction in Magurele-Bucharest (RO). Here an advanced source of gamma photons with unprecedented specifications of brilliance (>1021), monochromaticity (0.5%) and energy tunability (0.2-19.5 MeV) is being built, based on Inverse Compton Scattering in the head-on configuration between an electron beam of maximum energy 750 MeV and a high quality high power ps laser beam. These requirements make the ELI-NP GBS an advanced and challenging gamma ray source. The electron beam dynamics analysis and control regarding the machine sensitivity to the possible jitter and misalignments are presented. The effects on the beam quality are illustrated providing the basis for the alignment procedure and jitter tolerances.

  17. Nonlinear Dynamic Analysis of Functionally Graded Timoshenko Beam fixed to a Rotating Hub

    Science.gov (United States)

    Panigrahi, B.; Pohit, G.

    2016-08-01

    The present work accounts centrifugal stiffening effect on the nonlinear vibration response of an FGM Timoshenko beam. Analysis is carried out for a cantilever beam fixed with a rotating hub. Material is assumed to have a gradation relation along the depth of the beam. Centrifugal force and axial displacement raised due to the rotating hub is incorporated in the strain energy equations. Subsequent to this, an iterative technique is employed to obtain amplitude dependent vibration response of a rotating Timoshenko beam while material follows a gradation relation along the beam depth. Main objective of the work is to obtain the effects of rotational speeds, hub radius, and different gradation relations on the linear as well as nonlinear frequencies and mode shapes.

  18. Dependability analysis of a safety critical system the LHC beam dumping system at CERN

    CERN Document Server

    Filippini, R

    2006-01-01

    This thesis presents the dependability study of the Beam Dumping System of the Large Hadron Collider (LHC), the high energy particle accelerator to be commissioned at CERN in summer 2007. There are two identical, independent LHC Beam Dumping Systems (LBDS), one per LHC beam, each consisting of a series of magnets that extract the particle beam from the LHC ring into the extraction line leading to the absorbing block. The consequences of a failure within the LBDS can be very severe. This risk is reduced by applying redundancy to the design of the most critical components and on-line surveillance that, in case of a detected failure, issues a safe operation abort, called false beam dump. The system has been studied applying Failure Modes Effects and Criticality Analysis (FMECA) and reliability prediction. The system failure processes have been represented with a state transition diagram, governed by a Markov regenerative stochastic process, and analysed for different operational scenarios for one year of operati...

  19. Experimental Motion Analysis of Radially Rotating Beams Using High-Speed Camera and Motion Analyzer

    Directory of Open Access Journals (Sweden)

    K.H. Low

    1996-01-01

    Full Text Available Although strain gauges can be attached to a system for vibration analysis, wires connected to the strain gauges may disturb the system and affect the accuracy of the strain measurement. As an alternative, this work presents the use of a high-speed camera combined with a motion analyzer to study the motion of rotating flexible beams. One end of the beam is rigidly connected to a motor, while the other end is free. White stickers placed on selected points on a given beam are the reference points in a digitization process. The modes of the vibrating beams can be filmed and analyzed. The vibration parameters, such as deflection and frequency, can be obtained by using a film motion analyzer. The results show that the beam does not behave in a clamped-free or a pinned-free fashion, but instead occurs at an intermediate boundary between these two classical conditions.

  20. Free Vibration Analysis of a Cross-Ply Laminated Composite Beam on Pasternak Foundation

    Directory of Open Access Journals (Sweden)

    R. A. Jafari-Talookolaei

    2007-01-01

    Full Text Available In this study, free vibration analysis of a cross-ply laminated composite beam (LCB on Pasternak foundation was investigated. Natural frequencies of beam on Pasternak foundation are computed using finite element method (FEM on the basis of Timoshenko beam theory. Effect of both shear deformation and rotary inertia are implemented in the modeling of stiffness and mass matrices. The model was designed in such a way that it can be used for single-stepped cross-section, stepped foundation and multi-span beams. Results of few examples are compared with finding in literature and good agreements were achieved. Natural frequencies of LCBs with different layers arrangements (symmetric and non-symmetric are compared. For multi-span beam, variation of frequency with respect to number of spans was also studied.

  1. NONLINEAR ANALYSIS OF CFRP- PRESTRESSED CONCRETE BEAMS SUBJECTED TO INCREMENTAL STATIC LOADING BY FINITE ELEMENTS

    Directory of Open Access Journals (Sweden)

    Husain M. Husain

    2013-05-01

    Full Text Available In this work a program is developed to carry out the nonlinear analysis (material nonlinearity of prestressed concrete beams using tendons of carbon fiber reinforced polymer (CFRP instead of steel. The properties of this material include high strength, light weight, and insusceptibility to corrosion and magnetism. This material is still under investigation, therefore it needs continuous work to make it beneficial in concrete design. Four beams which are tested experimentally by Yan et al. are examined by the developed computer program to reach a certain analytical approach of the design and analysis of such beams because there is no available restrictions or recommendations covering this material in the codes. The program uses the finite element analysis by dividing the beams into isoparametric 20-noded brick elements. The results obtained are good in comparison with experimental results.

  2. Analysis of bite marks in foodstuffs by computer tomography (cone beam CT)--3D reconstruction.

    Science.gov (United States)

    Marques, Jeidson; Musse, Jamilly; Caetano, Catarina; Corte-Real, Francisco; Corte-Real, Ana Teresa

    2013-12-01

    The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. This three-dimensional analysis is based on the registration of the surface from a bitten object. The authors propose to use Cone Beam Computed Tomography (CBCT), which is used in dental practice, in order to study the surface and interior of bitten objects and dental casts of suspects. In this study, CBCT is applied to the analysis of bite marks in foodstuffs, which may be found in a forensic case scenario. 6 different types of foodstuffs were used: chocolate, cheese, apple, chewing gum, pizza and tart (flaky pastry and custard). The food was bitten into and dental casts of the possible suspects were made. The dental casts and bitten objects were registered using an x-ray source and the CBCT equipment iCAT® (Pennsylvania, EUA). The software InVivo5® (Anatomage Inc, EUA) was used to visualize and analyze the tomographic slices and 3D reconstructions of the objects. For each material an estimate of its density was assessed by two methods: HU values and specific gravity. All the used materials were successfully reconstructed as good quality 3D images. The relative densities of the materials in study were compared. Amongst the foodstuffs, the chocolate had the highest density (median value 100.5 HU and 1,36 g/cm(3)), while the pizza showed to have the lowest (median value -775 HU and 0,39 g/cm(3)), on both scales. Through tomographic slices and three-dimensional reconstructions it was possible to perform the metric analysis of the bite marks in all the foodstuffs, except for the pizza. These measurements could also be obtained from the dental casts. The depth of the bite mark was also successfully determined in all the foodstuffs except for the pizza. Cone Beam Computed Tomography has the potential to become an important tool for forensic sciences, namely for the registration and analysis of bite marks in foodstuffs that may be found in a crime

  3. Nonlinear dynamic analysis of damaged Reddy-Bickford beams supported on an elastic Pasternak foundation

    Science.gov (United States)

    Stojanović, Vladimir; Petković, Marko D.

    2016-12-01

    Geometrically nonlinear free and forced vibrations of damaged high order shear deformable beams resting on a nonlinear Pasternak foundation are investigated in this paper. Equations of motion are derived for the beam which is under subjected combined action of arbitrarily distributed or concentrated transverse loading as well as axial loading. To account for shear deformations, the concept of high order shear deformation is used in comparison with the concept of first order shear deformation theory. Analyses are performed to investigate the effects of the specific stiffness of the foundation on the damaged beam frequencies and displacements with the aim of equalising the response of a damaged and an intact beam. According to that, functions of the foundation stiffness are determined depending on the location and size of the damage as a result of the possibility for the damaged beam to behave like one that is intact. An advanced p-version of the finite element method is developed for geometrically nonlinear vibrations of damaged Reddy-Bickford beams. The present study gives a clear view of the nonlinear dynamical behaviour of four types of beams according to high order shear deformation theory - an intact beam, a damaged beam, a damaged beam on an elastic foundation and intact beam on elastic foundation. The paper also presents the derivation of a new set of two nonlinear partial differential equations where only the transverse and axial displacements figure. The forced nonlinear vibrations problem is solved in the time domain using the Newmark integration method. Free vibration analysis carried out by harmonic balance and the use of continuation methods and backbone curves are constructed.

  4. Anisotropic beam model for analysis and design of passive controlled wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Branner, K.; Blasques, J.P.; Kim, T.; Fedorov, V.A.; Berring, P.; Bitsche, R.D.; Berggreen, C.

    2012-02-15

    The main objective of the project was, through theoretical and experimental research, to develop and validate a fully coupled, general beam element that can be used for advanced and rapid analysis of wind turbine blades. This is fully achieved in the project and the beam element has even been implemented in the aeroelastic code HAWC2. It has also been demonstrated through a parametric study in the project that a promising possibility with the tool is to reduce fatigue loads through structural couplings. More work is needed before these possibilities are fully explored and blades with structural couplings can be put into production. A cross section analysis tool BECAS (BEam Cross section Analysis Software) has been developed and validated in the project. BECAS is able to predict all geometrical and material induced couplings. This tool has obtained great interest from both industry and academia. The developed fully coupled beam element and cross section analysis tool has been validated against both numerical calculations and experimental measurements. Numerical validation has been performed against beam type calculations including Variational Asymptotical Beam Section Analysis (VABS) and detailed shell and solid finite element analyses. Experimental validation included specially designed beams with built-in couplings, a full-scale blade section originally without couplings, which subsequently was modified with extra composite layers in order to obtain measurable couplings. Both static testing and dynamic modal analysis tests have been performed. The results from the project now make it possible to use structural couplings in an intelligent manner for the design of future wind turbine blades. The developed beam element is especially developed for wind turbine blades and can be used for modeling blades with initial curvature (pre-bending), initial twist and taper. Finally, it have been studied what size of structural couplings can be obtained in current and future

  5. Simulating the Effects of Surface Roughness on Reinforced Concrete T Beam Bridge under Single and Multiple Vehicles

    Directory of Open Access Journals (Sweden)

    Rahul Kalyankar

    2016-01-01

    Full Text Available This research focuses on the application of the spatial system of finite element modeling for the vehicle-bridge interaction on reinforced concrete US Girder Bridge in order to obtain the effect of surface roughness. Single vehicle and multiple vehicles on reinforced concrete T beam bridge were studied with variable surface roughness profiles. The effects of six different surface roughness profiles (very good, good, measured, average, poor, and very poor were investigated for vehicle-bridge interaction. The values of the Dynamic Amplification Factor (DAF were obtained for single and multiple vehicles on T Beam Bridge for different surface roughness profiles, along with the distances between the axles of heavy vehicle. It was observed that when the bridge has very good, good, measured, and average surface roughness, the DAF values for the single vehicle over the bridge were observed to be within acceptable limits specified by AASHTO. However, for the bridge with multiple vehicles only very good and measured surface roughness profiles showed a DAF and vehicle axle distances within the acceptable limits. From the current studies, it was observed that the spatial system showed reliable responses for predicting the behavior of the bridge under variable road surface roughness conditions and was reliable in vehicle axle detection, and therefore, it has a potential to be use for realistic simulations.

  6. Crack modelling and detection in Timoshenko FGM beam under transverse vibration using frequency contour and response surface model with GA

    Science.gov (United States)

    Banerjee, Amit; Panigrahi, Brajesh; Pohit, G.

    2016-04-01

    In the present work, dynamic response of cracked Timoshenko beam with functionally graded material properties are obtained by a numerical technique using Ritz approximation. In order to verify the applicability and performance of the formulation, comparisons of the present numerical method with three-dimensional FEM models are made. Crack is assumed to be transverse and open throughout the vibration cycle. Two different crack detection techniques have been proposed. Results obtained by the numerical technique are used in both of the crack detection techniques. In the first technique, the frequency contours with respect to crack location and size are plotted and the intersection of contours of different modes helps in the prediction of crack location and size. In the second technique, crack is modelled using response surface methodology (RSM). The sum of the squared errors between the numerical and RSM regression model natural frequencies is used as the objective function. This objective function is minimised using genetic algorithm optimisation technique. Both the crack detection techniques and the numerical analysis have shown good agreement with each other.

  7. Dynamical evolution of the surface microrelief under multiple-pulse-laser irradiation: An analysis based on surface-scattered waves

    Science.gov (United States)

    Barborica, A.; Mihailescu, I. N.; Teodorescu, V. S.

    1994-03-01

    We introduce a theoretical analysis of the temporal and spatial evolution of the surface topography of solids following interference between incident and scattered pulsed laser beams. The essential role played by the nonlinear delayed feedback in the laser-radiation-surface system is considered. We show that it finally determines the surface topography evolution from pulse to pulse. In order to complete the analysis, numerical calculations have been conducted under the hypothesis of strong attenuation of laser radiation into the sample and of a limited heat diffusion during the action of a laser pulse. We predict an evolution from very simple to complex (chaotic) structures under multiple-pulse-laser irradiation of solid surfaces. This evolution is determined by some key irradiation parameters; initial surface microrelief, incident laser intensity, and the number of applied laser pulses. Experiments were performed in order to check the main predictions of the theoretical analysis. The system of transversal excited atmospheric pressure-CO2 laser radiation (λ=10.6 μm)-interacting with fused silica was chosen as appropriate for performing test experiments. Optical microscopy studies of laser-treated zones evidenced special modifications of the surface topography in good accordance with the conclusions following from the theoretical analysis. The theoretical analysis is also in good agreement with some available data from the literature, at the same time providing a coherent interpretation of previously unexplained behaviors.

  8. Experimental Dynamic Analysis of Nonlinear Beams under Moving Loads

    Directory of Open Access Journals (Sweden)

    A. Bellino

    2012-01-01

    Full Text Available It is well known that nonlinear systems, as well as linear time-varying systems, are characterized by non-stationary response signals. In this sense, they both show natural frequencies that are not constant over time; this variation has however different origins: for a time-varying system the mass, and possibly the stiffness distributions, are changing over time, while for a nonlinear system the natural frequencies are amplitude-dependent. An interesting case of time-varying system occurs when analyzing the transit of a train over a railway bridge, easily simulated by the crossing of a moving load over a beam. In this case, the presence of a nonlinearity in the beam behaviour can cause a significant alteration of the modal parameters extracted from the linearized model, such that the contributions of the two effects are no more distinguishable.

  9. Data Analysis and Simulation for the RICH Upgrade Test Beam

    CERN Document Server

    Lalanne, Louis-Alexandre

    2017-01-01

    The LHCb experiment is one of the four particles physics experiments collecting data at the Large Hadron Collider. One of its key detector components is the Ring-Imaging Cherenkov (RICH) system. This provides charged particle identification over a wide momentum range, from 2–100 GeV/c. In order to increase the readout frequency from 1MHz to 40MHz RICH detectors will be upgrade in 2020. Prototypes are designed and tested by the RICH upgrade group of CERN. A full GEANT4 simulation have been programmed to reproduce the experimental test beam set-up and to produce MonteCarlo data. Those data have been compared to data from the test beam in order to study and compared the photon yield and the Cherenkov angle resolution of the most recent version of RICH.

  10. Repository surface design site layout analysis

    Energy Technology Data Exchange (ETDEWEB)

    Montalvo, H.R.

    1998-02-27

    The purpose of this analysis is to establish the arrangement of the Yucca Mountain Repository surface facilities and features near the North Portal. The analysis updates and expands the North Portal area site layout concept presented in the ACD, including changes to reflect the resizing of the Waste Handling Building (WHB), Waste Treatment Building (WTB), Carrier Preparation Building (CPB), and site parking areas; the addition of the Carrier Washdown Buildings (CWBs); the elimination of the Cask Maintenance Facility (CMF); and the development of a concept for site grading and flood control. The analysis also establishes the layout of the surface features (e.g., roads and utilities) that connect all the repository surface areas (North Portal Operations Area, South Portal Development Operations Area, Emplacement Shaft Surface Operations Area, and Development Shaft Surface Operations Area) and locates an area for a potential lag storage facility. Details of South Portal and shaft layouts will be covered in separate design analyses. The objective of this analysis is to provide a suitable level of design for the Viability Assessment (VA). The analysis was revised to incorporate additional material developed since the issuance of Revision 01. This material includes safeguards and security input, utility system input (size and location of fire water tanks and pump houses, potable water and sanitary sewage rates, size of wastewater evaporation pond, size and location of the utility building, size of the bulk fuel storage tank, and size and location of other exterior process equipment), main electrical substation information, redundancy of water supply and storage for the fire support system, and additional information on the storm water retention pond.

  11. Heavy Neutral Beam Probe for Edge Plasma Analysis in Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Castracane, J.

    2001-01-04

    The Heavy Neutral Beam Probe (HNBP) developed initially with DOE funding under the Small Business Innovation Research (SBIR) program was installed on the Tokamak de Varennes (TdeV) at the CCFM. This diagnostic was designed to perform fundamental measurements of edge plasma properties. The hardware was capable of measuring electron density and potential profiles with high spatial and temporal resolution. Fluctuation spectra for these parameters were obtained with HNBP for transport studies.

  12. Influence of standard RF coil materials on surface and buildup dose from a 6 MV photon beam in magnetic field.

    Science.gov (United States)

    Ghila, A; Fallone, B G; Rathee, S

    2016-11-01

    Magnetic resonance guided teletherapy systems aspire to image the patient concurrently with the radiation delivery. Thus, the radiofrequency (RF) coils used for magnetic resonance imaging, placed on or close to patient skin and in close proximity to the treatment volume, would be irradiated leading to modifications of radiation dose to the skin and in the buildup region. The purpose of this work is to measure and assess these dose modifications due to standard off-the-shelf RF coil materials. A typical surface coil was approximated as layered sheets of polycarbonate, copper tape, and Teflon to emulate the base, conductor, and cover, respectively. A separate investigation used additional coil materials, such as copper pipe, plastic coil housing, a typical coil padding material, and a thin copper conductor. The materials were placed in the path of a 6 MV photon beam at various distances from polystyrene phantoms in which the surface and buildup doses were measured. The experiments were performed on a clinical Varian linac with no magnetic field and with a 0.21 T electromagnet producing a magnetic field parallel to the beam central axis. The authors repeated similar experiments in the presence of a 0.22 T magnetic field oriented perpendicular to the beam central axis using an earlier linac-MR prototype, with a biplanar permanent magnet. The radiation detectors used for the measurements were two different parallel plate ion chambers and GAFChromic films. A typical open beam surface dose of 20% (relative to open beam Dmax) was increased to 63% by the coil padding material and to >74% by all other materials when placed in direct contact with the phantom, irrespective of magnetic field presence or orientation. Without a magnetic field, the surface dose decreased as the test materials were moved away from the phantom surface toward the radiation source, reaching between 30% and 40% at 10 cm gap between the phantom and the test materials. In the presence of the transverse

  13. Layerwise Analysis of Thermal Shape Control in Graded Piezoelectric Beams

    Science.gov (United States)

    Lee, Ho-Jun

    2003-01-01

    A layerwise finite element formulation developed for piezoelectric materials is used to investigate the displacement and stress response of a functionally graded piezoelectric bimorph actuator. The formulation is based on the principles of linear thermopiezoelectricity and accounts for the coupled mechanical, electrical, and thermal response of piezoelectric materials. The layerwise laminate theory is implemented into a linear beam element in order to provide a more accurate representation of the transverse and shear effects that are induced by increased inhomogeneities introduced through-the-thickness by using functionally graded materials. The accuracy of the formulation is verified with previously published experimental results for a piezoelectric bimorph actuator. Additional studies are conducted to analyze the impact of electric and thermal loads on the deflections and stresses in a bimorph actuator. Results of the study help demonstrate the capability of the layerwise theory to provide a more complete representation of shear effects that are no longer negligible even in thin piezoelectric beams. In addition, the effects of varying piezoelectric properties through-the-thickness of the beam are shown to provide additional benefits in minimizing the induced deformations and stresses.

  14. Thermal analysis of injection beam dump of high-intensity rapid-cycling synchrotron in J-PARC

    Science.gov (United States)

    Kamiya, J.; Saha, P. K.; Yamamoto, K.; Kinsho, M.; Nihei, T.

    2017-10-01

    The beam dump at the beam injection area in the J-PARC 3-GeV rapid cycling synchrotron (RCS) accepts beams that pass through the charge exchange foil without ideal electron stripping during the multi-turn beam injection. The injection beam dump consists of the beam pipe, beam stopper, radiation shield, and cooling mechanism. The ideal beam power into the injection beam dump is 400 W in the case of design RCS extraction beam power of 1 MW with a healthy foil, which has 99.7 % charge stripping efficiency. On the other hand, as a radiation generator, the RCS is permitted to be operated with maximum average beam power of 4 kW into the injection beam dump based on the radiation shielding calculation, in consideration of lower charge stripping efficiency due to the foil deterioration. In this research, to evaluate the health of the RCS injection beam dump system from the perspective of the heat generation, a thermal analysis was performed based on the actual configuration with sufficiently large region, including the surrounding concrete and soil. The calculated temperature and heat flux density distribution showed the validity of the mesh spacing and model range. The calculation result showed that the dumped 4 kW beam causes the temperature to increase up to 330, 400, and 140 °C at the beam pipe, beam stopper, and radiation shield, respectively. Although these high temperatures induce stress in the constituent materials, the calculated stress values were lower than the ultimate tensile strength of each material. Transient temperature analysis of the beam stopper, which simulated the sudden break of the charge stripper foil, demonstrated that one bunched beam pulse with the maximum beam power does not lead to a serious rise in the temperature of the beam stopper. Furthermore, from the measured outgassing rate of stainless steel at high temperature, the rise in beam line pressure due to additive outgassing from the heated beam pipe was estimated to have a negligible

  15. SURFACE TEXTURE ANALYSIS FOR FUNCTIONALITY CONTROL

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Andreasen, Jan Lasson; Tosello, Guido

    This document is used in connection with three exercises of 3 hours duration as a part of the course VISION ONLINE – One week course on Precision & Nanometrology. The exercises concern surface texture analysis for functionality control, in connection with three different case stories. This docume...... contains a short description of each case story, 3-D roughness parameters analysis and relation with the product’s functionality.......This document is used in connection with three exercises of 3 hours duration as a part of the course VISION ONLINE – One week course on Precision & Nanometrology. The exercises concern surface texture analysis for functionality control, in connection with three different case stories. This document...

  16. In situ investigation of the surface silvering of late Roman coins by combined use of high energy broad-beam and low energy micro-beam X-ray fluorescence techniques

    Energy Technology Data Exchange (ETDEWEB)

    Romano, F.P., E-mail: romanop@lns.infn.it [IBAM, CNR, Via Biblioteca 4, 95124 Catania (Italy); LNS, INFN, Via S. Sofia 62, 95123 Catania (Italy); Garraffo, S. [ITABC, CNR, Via Salaria km 29.300, 00016 Monterotondo, Roma (Italy); Pappalardo, L. [IBAM, CNR, Via Biblioteca 4, 95124 Catania (Italy); LNS, INFN, Via S. Sofia 62, 95123 Catania (Italy); Rizzo, F. [LNS, INFN, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, 95123 Catania (Italy)

    2012-07-15

    The compositional analysis of archeological metals performed with the X-ray Fluorescence technique (XRF) provides information on the ancient technology. One of the most interesting case-study concerns the techniques used by Romans for silvering the surface of coins. Different metallurgical processes have been suggested in previous studies. Recently the investigation has been addressed to the mercury-silvering and to its possible use in the mass-production of coins minted during the late period (after 294 AD). In the present paper the non-destructive investigation of the silvering process used for manufacturing the Roman nummi - the important typology of coin introduced by Diocletian in his monetary reform - is approached by the combined use of the standard X-Ray Fluorescence (XRF) and the low energy micro-X-Ray Fluorescence (LE-{mu}XRF) portable methods. The research was focused on the systematic determination of the mercury presence in a large number of samples and on its correlation with silver in the surface of the coins. 1041 Roman nummi belonging to the Misurata Treasure were analyzed in situ, at the Leptis Magna Museum (Al Khums, Libya). The treasure, composed of about 108 thousand silvered coins, gives the unique opportunity to study the Roman coinage in a wide interval of time (about 40 years in the period 294-333 AD) and in almost all the imperial mints operating in the Roman world. - Highlights: Black-Right-Pointing-Pointer Custom-building of a high energy broad-beam and a low energy micro-beam XRF Black-Right-Pointing-Pointer In situ analysis of the silvering methods in late Roman nummi with plated surfaces Black-Right-Pointing-Pointer The broad-beam XRF was applied for the detection of mercury traces in the coin alloy. Black-Right-Pointing-Pointer The low energy micro-XRF was used to scan the surface patina of the coins. Black-Right-Pointing-Pointer The correlation between mercury and silver at the coin surface was evidenced.

  17. Fuzzy analysis of serviceability limit state of slender steel beam under bending

    Energy Technology Data Exchange (ETDEWEB)

    Kala, Zdeněk; Valeš, Jan [Brno University of Technology, Faculty of Civil Engineering, Department of Structural Mechanics Vevefi St. 95, ZIP 602 00, Brno (Czech Republic)

    2015-03-10

    In the present paper, deformations of a beam under equal end moments solved with influence of lateral buckling are studied. It has been found by numerical studies that the lateral deflection of slender beam under major axis bending can be relatively high.The acceptability of high values of lateral deflections within the framework of serviceability limit state is discussed. In the next part of the paper, the limit value of maximum deflection was introduced as a fuzzy number. The fuzzy analysis of the maximum moment which causes the maximum deflection was carried out. The slendernesses of beams for which the serviceability limit state is the limiting state for design were identified.

  18. Analysis of the strength and stiffness of timber beams reinforced with carbon fiber and glass fiber

    Directory of Open Access Journals (Sweden)

    Juliano Fiorelli

    2003-06-01

    Full Text Available An experimental analysis of pinewood beams (Pinus caribea var hondurensis reinforced with glass and/or carbon fibers is discussed. The theoretical model employed to calculate the beam's bending strength takes into account the timber's ultimate limit states of tensile strength and failure by compression, considering a model of fragile elastic tension and plastic elastic compression. The validity of the theoretical model is confirmed by a comparison of the theoretical and experimental results, while the efficiency of the fiber reinforcement is corroborated by the increased strength and stiffness of the reinforced timber beams.

  19. Gaussian beam reflection and refraction by a spherical or parabolic surface: comparison of vectorial-law calculation with lens approximation.

    Science.gov (United States)

    Tkaczyk, Eric R; Mauring, Koit; Tkaczyk, Alan H

    2012-10-01

    A ray-tracing approach is used to demonstrate efficient application of the vectorial laws of reflection and refraction to computational optics problems. Both the full width at half-maximum (fwhm) and offset of Gaussian beams resulting from off-center reflection and refraction are calculated for spherical and paraboloidal surfaces of revolution. It is found that the magnification and displacement depend nonlinearly on the miscentering. For these geometries, the limits of accuracy of the lens approximation are examined quantitatively. In contrast to the ray-tracing solution, this paraxial approximation would predict a magnification of a beam's fwhm that is independent of miscentering, and an offset linearly proportional to the miscentering. The focusing property of paraboloidal surfaces of revolution is also derived in setting up the calculation.

  20. E-Beam Patterned Gold Nanodot Arrays on Optical Fiber Tips for Localized Surface Plasmon Resonance Biochemical Sensing

    Directory of Open Access Journals (Sweden)

    Yongbin Lin

    2010-10-01

    Full Text Available Electron beam lithography (EBL was used to directly pattern periodic gold nanodot arrays on optical fiber tips. Localized surface plasmon resonance of the E-beam patterned gold nanodot arrays on optical fiber tips was utilized for biochemical sensing. The advantage of the optical fiber based localized surface plasmon resonance (LSPR sensors is the convenience to work with and work in harsh environments. An optical fiber tip LSPR refractive index sensor of 196 nm per refractive index unit (RIU sensitivity has been demonstrated. The affinity sensing property of the fiber tip sensor was demonstrated using biotin/streptavidin as the receptor/analyte. The detection limit for streptavidin was determined to be 6 pM.