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Sample records for based electron microbeam

  1. Confocal Microscopy for Modeling Electron Microbeam Irradiation of Skin

    Energy Technology Data Exchange (ETDEWEB)

    Miller, John H.; Chrisler, William B.; Wang, Xihai; Sowa, Marianne B.

    2011-08-01

    For radiation exposures employing targeted sources such as particle microbeams, the deposition of energy and dose will depend on the spatial heterogeneity of the spample. Although cell structural variations are relatively minor for two-dimensional cell cultures, they can vary significantly for fully differential tissues. Employing high-resolution confocal microscopy, we have determined the spatial distribution, size, and shape of epidermal kerantinocyte nuclei for the full-thickness EpiDerm skin model (MatTek, Ashland, VA). Application of these data to claculate the microdosimetry and microdistribution of energy deposition by an electron microbeam is discussed.

  2. An accelerator-based neutron microbeam system for studies of radiation effects

    OpenAIRE

    Xu, Yanping; Randers-Pehrson, Gerhard; Marino, Stephen A.; Bigelow, Alan W.; Akselrod, Mark S.; Sykora, Jeff G.; Brenner, David J.

    2010-01-01

    A novel neutron microbeam is being developed at the Radiological Research Accelerator Facility (RARAF) of Columbia University. The RARAF microbeam facility has been used for studies of radiation bystander effects in mammalian cells for many years. Now a prototype neutron microbeam is being developed that can be used for bystander effect studies. The neutron microbeam design here is based on the existing charged particle microbeam technology at the RARAF. The principle of the neutron microbeam...

  3. Studying thin film damping in a micro-beam resonator based on non-classical theories

    Institute of Scientific and Technical Information of China (English)

    Mina Ghanbari; Siamak Hossainpour; Ghader Rezazadeh

    2016-01-01

    In this paper, a mathematical model is presented for studying thin film damping of the surrounding fluid in an in-plane oscillating micro-beam resonator. The proposed model for this study is made up of a clamped-clamped micro-beam bound between two fixed layers. The micro-gap between the micro-beam and fixed layers is filled with air. As classical theories are not properly capable of pre-dicting the size dependence behaviors of the micro-beam, and also behavior of micro-scale fluid media, hence in the presented model, equation of motion governing longitudinal displacement of the micro-beam has been extracted based on non-local elasticity theory. Furthermore, the fluid field has been modeled based on micro-polar theory. These coupled equations have been simplified using Newton-Laplace and continuity equations. After transforming to non-dimensional form and linearizing, the equations have been discretized and solved simultaneously using a Galerkin-based reduced order model. Considering slip boundary conditions and applying a complex frequency approach, the equivalent damping ratio and quality factor of the micro-beam resonator have been obtained. The obtained values for the quality factor have been compared to those based on classical theories. We have shown that applying non-classical theories underestimate the values of the quality factor obtained based on classical theo-ries. The effects of geometrical parameters of the micro-beam and micro-scale fluid field on the quality factor of the res-onator have also been investigated.

  4. Free Vibration of Size-Dependent Functionally Graded Microbeams Based on the Strain Gradient Reddy Beam Theory

    Science.gov (United States)

    Ansari, R.; Gholami, R.; Sahmani, S.

    2014-09-01

    The microscale vibration characteristics of microbeams made of functionally graded materials (FGMs) are investigated based on the strain gradient Reddy beam theory capable of capturing the size effect. The non-classical governing differential equations, together with the corresponding boundary conditions, are obtained using Hamilton's principle. Then, the free vibration problem of simply supported FGM microbeams is solved using the Navier solution. The natural frequencies of FGM microbeams are calculated corresponding to a wide range of dimensionless length scale parameters, material property gradient indices, and aspect ratios to illustrate the influences of size effect on the vibrational response of FGM microbeams.

  5. Computational Dosimetry for Electron Microbeams: Monte-Carlo Track Simulation with Confocal Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miller, John H.; Wilson, W E.; Lynch, D J.; Resat, Marianne S.; Trease, Harold E.

    2001-10-15

    Both in vitro and in vivo experiments show that cells that do not receive energy directly from the radiation field (bystanders) respond to radiation exposure. This effect is most easily demonstrated with radiation fields composed of particles with high linear energy transfer (LET) that traverse only a few cells before they are stopped. Even at a moderate fluence of high-LET radiation only a small fraction of cells in the irradiated population are hit; hence, many bystanders are present. Low-LET radiation tends to generate a homogeneous distribution of dose at the cellular level so that identifying bystanders is much more difficult than in experiments with the same fluence of high-LET radiation. Experiments are underway at several laboratories to characterize bystander responses induced by low-LET radiation. At the Pacific Northwest National Laboratory, experiments of this type are being carried out with an electron microbeam. A cell selected to receive energy directly from the irradiation source is placed over a hole in a mask that covers an electron gun. Monte Carlo simulations by Miller et al.(1) suggest that individual mammalian cells in a confluent monolayer could be targeted for irradiation by 25 to 100 keV electrons with minimal dose leakage to their neighbors. These calculations were based on a simple model of the cellular monolayer in which cells were assumed to be cylindrically symmetric with concentric cytoplasm and nucleus. Radial profiles, the lateral extent of cytoplasm and nucleus as a function of depth into a cell, were obtained from confocal microscopy of HeLa-cell monolayers.

  6. Measurement of minute local strain in semiconductor materials and electronic devices by using a highly parallel X-ray microbeam

    CERN Document Server

    Matsui, J; Yokoyama, K; Takeda, S; Katou, M; Kurihara, H; Watanabe, K; Kagoshima, Y; Kimura, S

    2003-01-01

    We have developed an X-ray microbeam with a small angular divergence by adopting X-ray optics with successive use of asymmetric Bragg reflection from silicon crystals for the both polarizations of the synchrotron X-rays. The microbeam actually obtained is several microns in size and possesses an angular divergence of less than 2 arcsec which enables us to measure the strain of 10 sup - sup 5 -10 sup - sup 6. By scanning the sample against the microbeam, distribution of the minute local strain in various regions of semiconductor crystals for electronic devices, e.g., the strain around the SiO sub 2 /Si film edge in silicon devices, the strain in an InGaAsP/InP stripe laser were measured.

  7. Free vibration analysis of size-dependent cracked microbeam based on the modified couple stress theory

    Science.gov (United States)

    Sourki, R.; Hoseini, S. A. H.

    2016-04-01

    This paper investigates the analysis for free transverse vibration of a cracked microbeam based on the modified couple stress theory within the framework of Euler-Bernoulli beam theory. The governing equation and the related boundary conditions are derived by using Hamilton's principle. The cracked beam is modeled by dividing the beam into two segments connected by a rotational spring located at the cracked section. This model invokes the consideration of the additional strain energy caused by the crack and promotes a discontinuity in the bending slope. In this investigation, the influence of diverse crack position, crack severity, material length scale parameter as well as various Poisson's ratio on natural frequencies is studied. A comparison with the previously published studies is made, in which a good agreement is observed. The results illustrate that the aforementioned parameters are playing a significant role on the dynamic behavior of the microbeam.

  8. Physiologically gated micro-beam radiation therapy using electronically controlled field emission x-ray source array

    Science.gov (United States)

    Chtcheprov, Pavel; Hadsell, Michael; Burk, Laurel; Ger, Rachel; Zhang, Lei; Yuan, Hong; Lee, Yueh Z.; Chang, Sha; Lu, Jianping; Zhou, Otto

    2013-03-01

    Micro-beam radiation therapy (MRT) uses parallel planes of high dose narrow (10-100 um in width) radiation beams separated by a fraction of a millimeter to treat cancerous tumors. This experimental therapy method based on synchrotron radiation has been shown to spare normal tissue at up to 1000Gy of entrance dose while still being effective in tumor eradication and extending the lifetime of tumor-bearing small animal models. Motion during the treatment can result in significant movement of micro beam positions resulting in broader beam width and lower peak to valley dose ratio (PVDR), and thus can reduce the effectiveness of the MRT. Recently we have developed the first bench-top image guided MRT system for small animal treatment using a high powered carbon nanotube (CNT) x-ray source array. The CNT field emission x-ray source can be electronically synchronized to an external triggering signal to enable physiologically gated firing of x-ray radiation to minimize motion blurring. Here we report the results of phantom study of respiratory gated MRT. A simulation of mouse breathing was performed using a servo motor. Preliminary results show that without gating the micro beam full width at tenth maximum (FWTM) can increase by 70% and PVDR can decrease up to 50%. But with proper gating, both the beam width and PVDR changes can be negligible. Future experiments will involve irradiation of mouse models and comparing histology stains between the controls and the gated irradiation.

  9. Vibration analysis of a rotating functionally graded tapered microbeam based on the modified couple stress theory by DQEM

    Science.gov (United States)

    Ghadiri, Majid; Shafiei, Navvab; Alireza Mousavi, S.

    2016-09-01

    Due to having difficulty in solving governing nonlinear differential equations of a non-uniform microbeam, a few numbers of authors have studied such fields. In the present study, for the first time, the size-dependent vibration behavior of a rotating functionally graded (FG) tapered microbeam based on the modified couple stress theory is investigated using differential quadrature element method (DQEM). It is assumed that physical and mechanical properties of the FG microbeam are varying along the thickness that will be defined as a power law equation. The governing equations are determined using Hamilton's principle, and DQEM is presented to obtain the results for cantilever and propped cantilever boundary conditions. The accuracy and validity of the results are shown in several numerical examples. In order to display the influence of size on the first two natural frequencies and consequently changing of some important microbeam parameters such as material length scale, rate of cross section, angular velocity and gradient index of the FG material, several diagrams and tables are represented. The results of this article can be used in designing and optimizing elastic and rotary-type micro-electro-mechanical systems like micro-motors and micro-robots including rotating parts.

  10. Size-dependent dynamic pull-in instability of vibrating electrically actuated microbeams based on the strain gradient elasticity theory

    Science.gov (United States)

    Sedighi, Hamid M.

    2014-02-01

    This paper presents the impact of vibrational amplitude on the dynamic pull-in instability and fundamental frequency of actuated microbeams by introducing the second order frequency-amplitude relationship. The nonlinear governing equation of microbeam predeformed by an electric force including the fringing field effect, based on the strain gradient elasticity theory is considered. The predicted results of the strain gradient elasticity theory are compared with the outcomes that arise from the classical and modified couple stress theory. The influences of basic nondimensional parameters on the pull-in instability as well as the natural frequency are investigated by a powerful asymptotic approach namely the Parameter Expansion Method (PEM). It is demonstrated that two terms in series expansions are sufficient to produce an acceptable solution of the microstructure. The phase portrait of the microstructure shows that by increasing the actuation voltage parameter, the stable center point loses its stability and coalesces with unstable saddle node.

  11. Monte Carlo-based treatment planning system calculation engine for microbeam radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Rovira, I.; Sempau, J.; Prezado, Y. [Institut de Tecniques Energetiques, Universitat Politecnica de Catalunya, Diagonal 647, Barcelona E-08028 (Spain) and ID17 Biomedical Beamline, European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz B.P. 220, F-38043 Grenoble Cedex (France); Institut de Tecniques Energetiques, Universitat Politecnica de Catalunya, Diagonal 647, Barcelona E-08028 (Spain); Laboratoire Imagerie et modelisation en neurobiologie et cancerologie, UMR8165, Centre National de la Recherche Scientifique (CNRS), Universites Paris 7 et Paris 11, Bat 440., 15 rue Georges Clemenceau, F-91406 Orsay Cedex (France)

    2012-05-15

    Purpose: Microbeam radiation therapy (MRT) is a synchrotron radiotherapy technique that explores the limits of the dose-volume effect. Preclinical studies have shown that MRT irradiations (arrays of 25-75-{mu}m-wide microbeams spaced by 200-400 {mu}m) are able to eradicate highly aggressive animal tumor models while healthy tissue is preserved. These promising results have provided the basis for the forthcoming clinical trials at the ID17 Biomedical Beamline of the European Synchrotron Radiation Facility (ESRF). The first step includes irradiation of pets (cats and dogs) as a milestone before treatment of human patients. Within this context, accurate dose calculations are required. The distinct features of both beam generation and irradiation geometry in MRT with respect to conventional techniques require the development of a specific MRT treatment planning system (TPS). In particular, a Monte Carlo (MC)-based calculation engine for the MRT TPS has been developed in this work. Experimental verification in heterogeneous phantoms and optimization of the computation time have also been performed. Methods: The penelope/penEasy MC code was used to compute dose distributions from a realistic beam source model. Experimental verification was carried out by means of radiochromic films placed within heterogeneous slab-phantoms. Once validation was completed, dose computations in a virtual model of a patient, reconstructed from computed tomography (CT) images, were performed. To this end, decoupling of the CT image voxel grid (a few cubic millimeter volume) to the dose bin grid, which has micrometer dimensions in the transversal direction of the microbeams, was performed. Optimization of the simulation parameters, the use of variance-reduction (VR) techniques, and other methods, such as the parallelization of the simulations, were applied in order to speed up the dose computation. Results: Good agreement between MC simulations and experimental results was achieved, even at

  12. X-ray microbeams based on Kumakhov polycapillary optics and its applications: Analytical consideration

    Indian Academy of Sciences (India)

    A Yu Romanov

    2011-02-01

    Kumakhov polycapillary optics is based on the effective passage of X-ray radiation through bundles of monocapillaries of various configurations. The passage of radiation takes place because of the total external reflection of X-rays from the inner capillary walls. In this work,the basic characteristics of intense quasi-parallel X-ray polycapillary microbeams from a laboratory source with microfocus X-ray tube/polycapillary cylindrical structure are investigated theoretically (analytical consideration). The data generated from theoretical estimations are compared with the experimental results. Several new generations of X-ray analytical devices like, laboratory synchrotron, fluorescent spectrometers, reflectometers/refractometers, diffractometers, X-ray microscopes and combinations of several such devices, are developed based on polycapillary optics. Besides, a number of devices can be developed for the most modern research problems such as nanomateriology, namely, X-ray nanoscanner, portable X-ray nanothickness indicator etc. X-ray tubes and the radiators, specially developed for polycapillary optics as efficiently as possible, are used in all the devices mentioned above.

  13. Comparative Dosimetric Estimates of a 25 keV Electron Micro-beam with three Monte Carlo Codes

    International Nuclear Information System (INIS)

    The calculations presented compare the different performances of the three Monte Carlo codes PENELOPE-1999, MCNP-4C and PITS, for the evaluation of Dose profiles from a 25 keV electron micro-beam traversing individual cells. The overall model of a cell is a water cylinder equivalent for the three codes but with a different internal scoring geometry: hollow cylinders for PENELOPE and MCNP, whereas spheres are used for the PITS code. A cylindrical cell geometry with scoring volumes with the shape of hollow cylinders was initially selected for PENELOPE and MCNP because of its superior simulation of the actual shape and dimensions of a cell and for its improved computer-time efficiency if compared to spherical internal volumes. Some of the transfer points and energy transfer that constitute a radiation track may actually fall in the space between spheres, that would be outside the spherical scoring volume. This internal geometry, along with the PENELOPE algorithm, drastically reduced the computer time when using this code if comparing with event-by-event Monte Carlo codes like PITS. This preliminary work has been important to address dosimetric estimates at low electron energies. It demonstrates that codes like PENELOPE can be used for Dose evaluation, even with such small geometries and energies involved, which are far below the normal use for which the code was created. Further work (initiated in Summer 2002) is still needed however, to create a user-code for PENELOPE that allows uniform comparison of exact cell geometries, integral volumes and also microdosimetric scoring quantities, a field where track-structure codes like PITS, written for this purpose, are believed to be superior

  14. Comparative Dosimetric Estimates of a 25 keV Electron Micro-beam with three Monte Carlo Codes

    Energy Technology Data Exchange (ETDEWEB)

    Mainardi, Enrico; Donahue, Richard J.; Blakely, Eleanor A.

    2002-09-11

    The calculations presented compare the different performances of the three Monte Carlo codes PENELOPE-1999, MCNP-4C and PITS, for the evaluation of Dose profiles from a 25 keV electron micro-beam traversing individual cells. The overall model of a cell is a water cylinder equivalent for the three codes but with a different internal scoring geometry: hollow cylinders for PENELOPE and MCNP, whereas spheres are used for the PITS code. A cylindrical cell geometry with scoring volumes with the shape of hollow cylinders was initially selected for PENELOPE and MCNP because of its superior simulation of the actual shape and dimensions of a cell and for its improved computer-time efficiency if compared to spherical internal volumes. Some of the transfer points and energy transfer that constitute a radiation track may actually fall in the space between spheres, that would be outside the spherical scoring volume. This internal geometry, along with the PENELOPE algorithm, drastically reduced the computer time when using this code if comparing with event-by-event Monte Carlo codes like PITS. This preliminary work has been important to address dosimetric estimates at low electron energies. It demonstrates that codes like PENELOPE can be used for Dose evaluation, even with such small geometries and energies involved, which are far below the normal use for which the code was created. Further work (initiated in Summer 2002) is still needed however, to create a user-code for PENELOPE that allows uniform comparison of exact cell geometries, integral volumes and also microdosimetric scoring quantities, a field where track-structure codes like PITS, written for this purpose, are believed to be superior.

  15. A history of laser scissors (microbeams).

    Science.gov (United States)

    Berns, Michael W

    2007-01-01

    This introductory chapter reviews the history of microbeams starting with the original UV microbeam work of Tchakhotine in 1912 and covers the progress and application of microbeams through 2006. The main focus of the chapter is on laser "scissors" starting with Marcel Bessis' and colleagues work with the ruby laser microbeam in Paris in 1962. Following this introduction, a section is devoted to describing the different laser microbeam systems and then the rest of the chapter is devoted to applications in cell and developmental biology. The approach is to focus on the organelle/structure and describe how the laser microbeam has been applied to studying its structure and/or function. Since considerable work has been done on chromosomes and the mitotic spindle (Section V.A and C), these topics have been divided in distinct subsections. Other topics discussed are injection of foreign DNA through the cell membrane (optoporation/optoinjection), cell migration, the nucleolus, mitochondria, cytoplasmic filaments, and embryos fate-mapping. A final technology section is devoted to discussing the pros and cons of building/buying your own laser microbeam system and the option of using the Internet-based RoboLase system. Throughout the chapter, reference is made to other chapters in the book that go into more detail on the subjects briefly mentioned. PMID:17586253

  16. The Amsterdam proton microbeam

    International Nuclear Information System (INIS)

    The aim of the work presented in this thesis is to develop a microbeam setup such that small beam spot sizes can be produced routinely, and to investigate the capabilities of the setup for micro-PIXE analysis. The development and performance of the Amsterdam proton microbeam setup are described. The capabilities of the setup for micro-PIXE are shown with an investigation into the presence of trace elements in human hair. (Auth.)

  17. Analysis of pull-in instability of geometrically nonlinear microbeam using radial basis artificial neural network based on couple stress theory.

    Science.gov (United States)

    Heidari, Mohammad; Heidari, Ali; Homaei, Hadi

    2014-01-01

    The static pull-in instability of beam-type microelectromechanical systems (MEMS) is theoretically investigated. Two engineering cases including cantilever and double cantilever microbeam are considered. Considering the midplane stretching as the source of the nonlinearity in the beam behavior, a nonlinear size-dependent Euler-Bernoulli beam model is used based on a modified couple stress theory, capable of capturing the size effect. By selecting a range of geometric parameters such as beam lengths, width, thickness, gaps, and size effect, we identify the static pull-in instability voltage. A MAPLE package is employed to solve the nonlinear differential governing equations to obtain the static pull-in instability voltage of microbeams. Radial basis function artificial neural network with two functions has been used for modeling the static pull-in instability of microcantilever beam. The network has four inputs of length, width, gap, and the ratio of height to scale parameter of beam as the independent process variables, and the output is static pull-in voltage of microbeam. Numerical data, employed for training the network, and capabilities of the model have been verified in predicting the pull-in instability behavior. The output obtained from neural network model is compared with numerical results, and the amount of relative error has been calculated. Based on this verification error, it is shown that the radial basis function of neural network has the average error of 4.55% in predicting pull-in voltage of cantilever microbeam. Further analysis of pull-in instability of beam under different input conditions has been investigated and comparison results of modeling with numerical considerations shows a good agreement, which also proves the feasibility and effectiveness of the adopted approach. The results reveal significant influences of size effect and geometric parameters on the static pull-in instability voltage of MEMS.

  18. Self-consistent depth profiling and imaging of GaN-based transistors using ion microbeams

    Energy Technology Data Exchange (ETDEWEB)

    Redondo-Cubero, A., E-mail: andres.redondo@uam.es [IPFN, Instituto Superior Técnico, Campus Tecnológico e Nuclear, Universidade de Lisboa, 2686-953 Bobadela (Portugal); Departamento de Física Aplicada y Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Corregidor, V. [IPFN, Instituto Superior Técnico, Campus Tecnológico e Nuclear, Universidade de Lisboa, 2686-953 Bobadela (Portugal); Vázquez, L. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid (Spain); Alves, L.C. [C2TN, Instituto Superior Técnico, Campus Tecnológico e Nuclear, Universidade de Lisboa, 2686-953 Bobadela (Portugal)

    2015-04-01

    Using an ion microprobe, a comprehensive lateral and in-depth characterization of a single GaN-based high electron mobility transistor is carried out by means of Rutherford backscattering spectrometry (RBS) in combination with particle induced X-ray emission (PIXE). Elemental distribution was obtained for every individual section of the device (wafer, gate and source contact), identifying the basic constituents of the transistor (including the detection of the passivant layer) and checking its homogeneity. A self-consistent analysis of each individual regions of the transistor was carried out with a simultaneous fit of RBS and PIXE spectra with two different beam conditions. Following this approach, the quantification of the atomic content and the layer thicknesses was successfully achieved overcoming the mass-depth ambiguity of certain elements.

  19. Size effect on the static behavior of electrostatically actuated microbeams

    Institute of Scientific and Technical Information of China (English)

    Li Yin; Qin Qian; Lin Wang

    2011-01-01

    We present a new analytical model for electrostatically actuated microbeams to explore the size effect by using the modified couple stress theory and the minimum total potential energy principle. A material length scale parameter is introduced to represent the size-dependent characteristics of microbeams. This model also accounts for the nonlinearities associated with the mid-plane stretching force and the electrostatical force. Numerical analysis for microbeams with clamped-clamped and cantilevered conditions has been performed. It is found that the intensity of size effect is closely associated with the thickness of the microbeam, and smaller beam thickness displays stronger size effect and hence yields smaller deflection and larger pull-in voltage. When the beam thickness is comparable to the material length scale parameter, the size effect is significant and the present theoretical model including the material length scale parameter is adequate for predicting the static behavior of microbeam-based MEMS.

  20. Assessment of mechanical properties of metallic thin-films through micro-beam testing

    International Nuclear Information System (INIS)

    Microelectronic industry is driven by the continuous miniaturization process conducing to the introduction of materials with better performance. These materials are subjected to stresses mainly due to thermal mismatch, microstructural changes or process integration which can be in the origin of mechanical reliability issues. To study these phenomena and even electromigration a good mechanical characterization of the materials is needed. This work aims at developing tests to assess fracture and elastoplastic behavior of thin Cu films. The tests developed are based on the deflection of microbeams (micromachined using a focused ion beam) using a nanoindenter. Different test geometries for microbeams have been evaluated and quantitative data have been obtained combining experimental results with analytical or numerical models, depending on the property under study. Microbeam response shows a strong dependence on the orientation of the grains close to the fixed end. Grain orientation has been measured by electron backscatter diffraction and the plastic behavior has been modeled by the finite element method using an in-house crystal plasticity subroutine. The effect of film thickness on fracture energy has been determined from tests of notched beams. - Highlights: • Cu microbeams have been machined with a focused ion beam and tested at a TriboIndenter. • Crystal plasticity has been accounted for when modeling constitutive behavior of Cu. • Fracture energy has been calculated using notched microcantilever beams. • Fracture energy decreases with film thickness

  1. Assessment of mechanical properties of metallic thin-films through micro-beam testing

    Energy Technology Data Exchange (ETDEWEB)

    Trueba, M.; Gonzalez, D.; Elizalde, M.R.; Martínez-Esnaola, J.M. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastián (Spain); Hernandez, M.T.; Li, H.; Pantuso, D. [Design Technology Solutions, Intel Corporation, Hillsboro 97124, OR (United States); Ocaña, I., E-mail: iocana@ceit.es [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastián (Spain)

    2014-11-28

    Microelectronic industry is driven by the continuous miniaturization process conducing to the introduction of materials with better performance. These materials are subjected to stresses mainly due to thermal mismatch, microstructural changes or process integration which can be in the origin of mechanical reliability issues. To study these phenomena and even electromigration a good mechanical characterization of the materials is needed. This work aims at developing tests to assess fracture and elastoplastic behavior of thin Cu films. The tests developed are based on the deflection of microbeams (micromachined using a focused ion beam) using a nanoindenter. Different test geometries for microbeams have been evaluated and quantitative data have been obtained combining experimental results with analytical or numerical models, depending on the property under study. Microbeam response shows a strong dependence on the orientation of the grains close to the fixed end. Grain orientation has been measured by electron backscatter diffraction and the plastic behavior has been modeled by the finite element method using an in-house crystal plasticity subroutine. The effect of film thickness on fracture energy has been determined from tests of notched beams. - Highlights: • Cu microbeams have been machined with a focused ion beam and tested at a TriboIndenter. • Crystal plasticity has been accounted for when modeling constitutive behavior of Cu. • Fracture energy has been calculated using notched microcantilever beams. • Fracture energy decreases with film thickness.

  2. Physiologically gated microbeam radiation using a field emission x-ray source array

    Energy Technology Data Exchange (ETDEWEB)

    Chtcheprov, Pavel, E-mail: PavelC@unc.edu, E-mail: zhou@email.unc.edu [Department of Biomedical Engineering, University of North Carolina, 152 MacNider Hall, Campus Box 7575, Chapel Hill, North Carolina 27599 (United States); Burk, Laurel; Inscoe, Christina; Ger, Rachel; Hadsell, Michael; Lu, Jianping [Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599 (United States); Yuan, Hong [Department of Radiology, University of North Carolina, 2006 Old Clinic, CB #7510, Chapel Hill, North Carolina 27599 (United States); Zhang, Lei [Department of Applied Physical Sciences, University of North Carolina, Chapman Hall, CB#3216, Chapel Hill, North Carolina 27599 (United States); Chang, Sha [Department of Radiation Oncology, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 and UNC Lineberger Comprehensive Cancer Center, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 (United States); Zhou, Otto, E-mail: PavelC@unc.edu, E-mail: zhou@email.unc.edu [Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599 and UNC Lineberger Comprehensive Cancer Center, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 (United States)

    2014-08-15

    Purpose: Microbeam radiation therapy (MRT) uses narrow planes of high dose radiation beams to treat cancerous tumors. This experimental therapy method based on synchrotron radiation has been shown to spare normal tissue at up to 1000 Gy of peak entrance dose while still being effective in tumor eradication and extending the lifetime of tumor-bearing small animal models. Motion during treatment can lead to significant movement of microbeam positions resulting in broader beam width and lower peak to valley dose ratio (PVDR), which reduces the effectiveness of MRT. Recently, the authors have demonstrated the feasibility of generating microbeam radiation for small animal treatment using a carbon nanotube (CNT) x-ray source array. The purpose of this study is to incorporate physiological gating to the CNT microbeam irradiator to minimize motion-induced microbeam blurring. Methods: The CNT field emission x-ray source array with a narrow line focal track was operated at 160 kVp. The x-ray radiation was collimated to a single 280 μm wide microbeam at entrance. The microbeam beam pattern was recorded using EBT2 Gafchromic{sup ©} films. For the feasibility study, a strip of EBT2 film was attached to an oscillating mechanical phantom mimicking mouse chest respiratory motion. The servo arm was put against a pressure sensor to monitor the motion. The film was irradiated with three microbeams under gated and nongated conditions and the full width at half maximums and PVDRs were compared. An in vivo study was also performed with adult male athymic mice. The liver was chosen as the target organ for proof of concept due to its large motion during respiration compared to other organs. The mouse was immobilized in a specialized mouse bed and anesthetized using isoflurane. A pressure sensor was attached to a mouse's chest to monitor its respiration. The output signal triggered the electron extraction voltage of the field emission source such that x-ray was generated only

  3. Microbeam radiation therapy

    Science.gov (United States)

    Laissue, Jean A.; Lyubimova, Nadia; Wagner, Hans-Peter; Archer, David W.; Slatkin, Daniel N.; Di Michiel, Marco; Nemoz, Christian; Renier, Michel; Brauer, Elke; Spanne, Per O.; Gebbers, Jan-Olef; Dixon, Keith; Blattmann, Hans

    1999-10-01

    The central nervous system of vertebrates, even when immature, displays extraordinary resistance to damage by microscopically narrow, multiple, parallel, planar beams of x rays. Imminently lethal gliosarcomas in the brains of mature rats can be inhibited and ablated by such microbeams with little or no harm to mature brain tissues and neurological function. Potentially palliative, conventional wide-beam radiotherapy of malignant brain tumors in human infants under three years of age is so fraught with the danger of disrupting the functional maturation of immature brain tissues around the targeted tumor that it is implemented infrequently. Other kinds of therapy for such tumors are often inadequate. We suggest that microbeam radiation therapy (MRT) might help to alleviate the situation. Wiggler-generated synchrotron x-rays were first used for experimental microplanar beam (microbeam) radiation therapy (MRT) at Brookhaven National Laboratory's National Synchrotron Light Source in the early 1990s. We now describe the progress achieved in MRT research to date using immature and adult rats irradiated at the European Synchrotron Radiation Facility in Grenoble, France, and investigated thereafter at the Institute of Pathology of the University of Bern.

  4. The GEANT4 toolkit for microdosimetry calculations: Application to microbeam radiation therapy (MRT)

    International Nuclear Information System (INIS)

    Theoretical dose distributions for microbeam radiation therapy (MRT) are computed in this paper using the GEANT4 Monte Carlo (MC) simulation toolkit. MRT is an innovative experimental radiotherapy technique carried out using an array of parallel microbeams of synchrotron-wiggler-generated x rays. Although the biological mechanisms underlying the effects of microbeams are still largely unknown, the effectiveness of MRT can be traced back to the natural ability of normal tissues to rapidly repair small damages to the vasculature, and on the lack of a similar healing process in tumoral tissues. Contrary to conventional therapy, in which each beam is at least several millimeters wide, the narrowness of the microbeams allows a rapid regeneration of the blood vessels along the beams' trajectories. For this reason the calculation of the ''valley'' dose is of crucial importance and the correct use of MC codes for such purposes must be understood. GEANT4 offers, in addition to the standard libraries, a specialized package specifically designed to deal with electromagnetic interactions of particles with matter for energies down to 250 eV. This package implements two different approaches for electron and photon transport, one based on evaluated data libraries, the other adopting analytical models. These features are exploited to cross-check theoretical computations for MRT. The lateral and depth dose profiles are studied for the irradiation of a 20 cm diameter, 20 cm long cylindrical phantom, with cylindrical sources of different size and energy. Microbeam arrays are simulated with the aid of superposition algorithms, and the ratios of peak-to-valley doses are computed for typical cases used in preclinical assays. Dose profiles obtained using the GEANT4 evaluated data libraries and analytical models are compared with simulation results previously obtained using the PENELOPE code. The results show that dose profiles computed with GEANT4's analytical model are almost

  5. Theoretical analysis and simulation of thermoelastic deformation of bimorph microbeams

    Institute of Scientific and Technical Information of China (English)

    SHANG; YuanFang; YE; XiongYing; FENG; JinYang

    2013-01-01

    In this paper, a purely mechanical model for the thermoelastic behavior of a bimorph microbeam is presented. The thermoelastic coupling problem of the microbeam is converted to a mechanical problem by simply replacing the thermal stress in the beam with a bulk force and a surface force. Thermoelastic deformation of the bimorph microbeams with constraints frequently used in micro-electro-mechanical systems (MEMS) devices has been derived based on this model and is characterized by FEA simulation. Coincidence of the results from theory and simulation demonstrates the validity of the model. The analysis shows that a bimorph microbeam with a soft constraint and a uniform temperature field has a larger thermoelastic deformation than that with a hard constraint and a linear temperature field. In addition to the adoption of materials with large CTE mismatch,thickness ratio and length ratio of the two layers need to be optimized to get a large thermoelastic deformation.

  6. Microbeam facility at NIRS

    International Nuclear Information System (INIS)

    Radiation biophysics or microdosimetry has suggested radiation effect mechanism. Full understanding of it has not yet been obtained. There are vast variety of events in physical, chemical and biological processes from at the time of irradiation to biological endpoints. Analysis of RBE-LET relation for biological endpoints like survival, mutation and transformation in cultured mammalian cells is still the leading subject to study the physical processes. The biological and repair processes have been studied phenomenologically through dose rate effect or fractionation experiment. Human genome project has accelerated biological sciences as a whole taking methodology of the molecular biology, where the mechanism is explained by molecules involved. We have thus to know entity and its (biological) function in every single process. Molecular biological approach in radiation biology has started and revealed several proteins being involved in the repair processes. Quantitative relation between phenomenological data like cell survivals and molecular processes, however, has been little known yet. A promising approach to fill this gap should be the study by microbeam, which enables us to see, for example, a deletion in chromosomal level by a single particle traverse of cell nucleus and may suggest possible molecular processes. Under this motivation we started feasibility study on installation of a microbeam port in our Tandem accelerator (5.1 MeV 4He2+). We have planned to adopt a lens focusing and a scanning system developed (by the Oxford microbeam Ltd) for the existing micro PIXE system in NIRS, which has basically achieved irradiation to a cell within a position resolution of 2 micrometer. There are two practical requirements, i.e. precise positioning and faster irradiation. These are described including research subjects planned. (author)

  7. 6th International Microbeam Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Dr Kevin M. Prise

    2004-01-01

    The extended abstracts which are submitted here present a summary of the proceedings of the 6th International Workshop/12th LH Gray Workshop: Microbeam Probes of Cellular Radiation Response, held at St. Catherine's College, University of Oxford, UK on March, 29th-31st, 2003. In 1993 the 4th LH Gray Workshop entitled ''Microbeam Probes of Cellular Radiation Response'' was held at the Gray Cancer Institute in Northwood. This was organized by Prof BD Michael, Dr M. Folkard and Dr KM Prise and brought together 40 participants interested in developing and applying new microbeam technology to problems in radiation biology (1). The workshop was an undoubted success and has spawned a series of subsequent workshops every two years. In the past, these workshops have been highly successful in bringing together groups interested in developing and applying micro-irradiation techniques to the study of cell and tissue damage by ionizing radiations. Following the first microbeam workshop, there has been a rapid growth in the number of centres developing radiobiology microbeams, or planning to do so and there are currently 15-20 worldwide. Much of the recent research using microbeams has used them to study low-dose effects and ''non-targeted'' responses such bystander effects, genomic instability and adaptive responses. The goal of the 6th workshop was to build on our knowledge of the development of microbeam approaches and the application to radiation biology in the future with the meeting stretching over a 3 day period. Over 80 participants reviewed the current state of radiobiology microbeam research worldwide and reported on new technological developments both in the fields of physics and biology.

  8. Microbeam Studies of the Bystander Response

    OpenAIRE

    Prise, Kevin M.; SCHETTINO, Giuseppe; Vojnovic, Boris; BELYAKOV, Oleg; Shao, Chunlin

    2009-01-01

    Microbeams have undergone a renaissance since their introduction and early use in the mid 60s. Recent advances in imaging, software and beam delivery have allowed rapid technological developments in microbeams for use in a range of experimental studies.

  9. Proton microbeam irradiation effects on PtBA polymer

    Indian Academy of Sciences (India)

    J Kamila; S Roy; K Bhattacharjee; B Rout; B N Dev; R Guico; J Wang; A W Haberl; P Ayyub; P V Satyam

    2006-04-01

    Proton beam lithography has made it possible to make various types of 3D-structures in polymers. Usually PMMA, SU-8, PS polymers have been used as resist materials for lithographic purpose. Microbeam irradiation effects on poly-tert-butyl-acrylate (PtBA) polymer using 2.0 MeV proton microbeam are reported. Preliminary results on pattern formation on PtBA are carried out as a function of fluence. After writing the pattern, a thin layer of Ge is deposited. Distribution of Ge in pristine and ion beam patterned surface of PtBA polymer is studied using the optical and secondary electron microscopic experimental methods.

  10. Improvement of the Energy Stability of the Single Ion Microbeam

    Institute of Scientific and Technical Information of China (English)

    ZHAN Furu; QI Xuehong; XU Mingliang; CHEN Lianyun; YU Zengliang

    2008-01-01

    Energy instability strongly affects the state and the beam size of the single ion microbeam. A facility based on the Generating Voltmeter was developed to improve the energy stability of the CAS-LIBB (Chinese Academy of Sciences, key laboratory of ion beam bioengineering) single ion microbeam. This paper presents the analysis of the energy instability of the single ion microbeam. A simplified theoretical model is set up to calculate the relationship between the energy instability and the beam spot size. By using this technique, the energy instability is adjusted to about 1%. Stable run-time is over 6 hours. The radius of the single ion beam is reduced by 10% compared to the previous one.

  11. Physics study of microbeam radiation therapy with PSI-version of Monte Carlo code GEANT as a new computational tool

    CERN Document Server

    Stepanek, J; Laissue, J A; Lyubimova, N; Di Michiel, F; Slatkin, D N

    2000-01-01

    Microbeam radiation therapy (MRT) is a currently experimental method of radiotherapy which is mediated by an array of parallel microbeams of synchrotron-wiggler-generated X-rays. Suitably selected, nominally supralethal doses of X-rays delivered to parallel microslices of tumor-bearing tissues in rats can be either palliative or curative while causing little or no serious damage to contiguous normal tissues. Although the pathogenesis of MRT-mediated tumor regression is not understood, as in all radiotherapy such understanding will be based ultimately on our understanding of the relationships among the following three factors: (1) microdosimetry, (2) damage to normal tissues, and (3) therapeutic efficacy. Although physical microdosimetry is feasible, published information on MRT microdosimetry to date is computational. This report describes Monte Carlo-based computational MRT microdosimetry using photon and/or electron scattering and photoionization cross-section data in the 1 e V through 100 GeV range distrib...

  12. Characterization of a tungsten/gas multislit collimator for microbeam radiation therapy at the European Synchrotron Radiation Facility

    Science.gov (United States)

    Bräuer-Krisch, E.; Bravin, A.; Zhang, L.; Siegbahn, E.; Stepanek, J.; Blattmann, H.; Slatkin, D. N.; Gebbers, J.-O.; Jasmin, M.; Laissue, J. A.

    2005-06-01

    Clinical microbeam radiation therapy (MRT) will require a multislit collimator with adjustable uniform slit widths to enable reliable Monte Carlo-based treatment planning. Such a collimator has been designed, fabricated of >99% tungsten [W] by Tecomet/Viasys (Woburn, Massachusetts, USA) and installed at the 6GeV electron-wiggler-generated hard x-ray ID17 beamline of the European Synchrotron Radiation Facility. Its pair of 125 parallel, 8mm deep, 0.100mm wide radiolucent slits, 0.400mm on center, are perfused with nitrogen gas [N2] to dissipate heat during irradiation. Major improvements in uniformity of microbeam widths and good peak/valley dose ratios combined with a very high dose rate in targeted tissues have been achieved.

  13. Elaborate calibration procedure for cell irradiation at the CAS-LIBB single-particle microbeam

    Institute of Scientific and Technical Information of China (English)

    Hu Zhi-Wen; Ding Ke-Jian; Yu Liang-Deng; Zhang Jun; Wu Li-Jun; Yu Zeng-Liang

    2006-01-01

    Single-particle microbeam is uniquely capable of precisely delivering a preset number of charged particles to individual cells or sub-cellular targets to be determined in vitro.It is crucial to find a reference point that relates the microbeam's location to the microscope's plane,and align individual targets at this reference point for cell irradiation.To choose an appropriate reference point,an approach based on analysing the intensity distribution of fluorescence in a thin scintillator excited by traversing particles is newly developed using the CAS-LIBB single-particle microbeam,which features decisive physical signification and sufficient resolution.As its bonus,this on-line analysis provides precise and fast response to the determination of beam profile and potentially optimizes the microbeam quality by further adjusting hardware setup.

  14. X-Tream quality assurance in synchrotron X-ray microbeam radiation therapy.

    Science.gov (United States)

    Fournier, Pauline; Cornelius, Iwan; Donzelli, Mattia; Requardt, Herwig; Nemoz, Christian; Petasecca, Marco; Bräuer-Krisch, Elke; Rosenfeld, Anatoly; Lerch, Michael

    2016-09-01

    Microbeam radiation therapy (MRT) is a novel irradiation technique for brain tumours treatment currently under development at the European Synchrotron Radiation Facility in Grenoble, France. The technique is based on the spatial fractionation of a highly brilliant synchrotron X-ray beam into an array of microbeams using a multi-slit collimator (MSC). After promising pre-clinical results, veterinary trials have recently commenced requiring the need for dedicated quality assurance (QA) procedures. The quality of MRT treatment demands reproducible and precise spatial fractionation of the incoming synchrotron beam. The intensity profile of the microbeams must also be quickly and quantitatively characterized prior to each treatment for comparison with that used for input to the dose-planning calculations. The Centre for Medical Radiation Physics (University of Wollongong, Australia) has developed an X-ray treatment monitoring system (X-Tream) which incorporates a high-spatial-resolution silicon strip detector (SSD) specifically designed for MRT. In-air measurements of the horizontal profile of the intrinsic microbeam X-ray field in order to determine the relative intensity of each microbeam are presented, and the alignment of the MSC is also assessed. The results show that the SSD is able to resolve individual microbeams which therefore provides invaluable QA of the horizontal field size and microbeam number and shape. They also demonstrate that the SSD used in the X-Tream system is very sensitive to any small misalignment of the MSC. In order to allow as rapid QA as possible, a fast alignment procedure of the SSD based on X-ray imaging with a low-intensity low-energy beam has been developed and is presented in this publication. PMID:27577773

  15. An automated scanning ion microbeam system

    Science.gov (United States)

    Requicha Ferreira, L. F.; Calvert, J. M.

    A standard Russian quadruplet lens system providing a microbeam on a 6 MV Van de Graaff accelerator has been fitted with an automated scanner. Samples housed in a special target chamber can be positioned accurately in two dimensions with respect to the beam. This is achieved by stepping motors. Two pairs of deflection coils provide electromagnetic deflection of the beam in two dimensions and the combination of electrical deflection of the beam and mechanical displacement of the sample permits scanning over a sample area of 10 mm × 10 mm. A staircase current waveform is provided to the coils and data accumulated at each step is routed appropriately to addresses in a large multichannel analyser (computer). The target chamber accommodates particle and X-ray detectors. The electronic operation is controlled by a microprocessor. The requirements of a complete scan are entered through the keyboard and the complete operation including writing of spectral data onto magnetic tape follows automatically. The arrangement has been used to study details of the oxidation behaviour of iron-chromium alloys as part of a larger programme of oxidation studies centred round the 18O(p, α) 15N reaction.

  16. An automated scanning ion microbeam system

    International Nuclear Information System (INIS)

    A standard Russian quadruplet lens system providing a microbeam on a 6 MV Van de Graaff accelerator has been fitted with an automated scanner. Samples housed in a special target chamber can be positioned accurately in two dimensions with respect to the beam. This is achieved by stepping motors. Two pairs of deflection coils provide electromagnetic deflection of the beam in two dimensions and the combination of electrical deflection of the beam and mechanical displacement of the sample permits scanning over a sample area of 10 mm x 10 mm. A staircase current waveform is provided to the coils and data accumulated at each step is routed appropriately to addresses in a large multichannel analyser (computer). The target chamber accommodates particle and X-ray detectors. The electronic operation is controlled by a microprocessor. The requirements of a complete scan are entered through the keyboard and the complete operation including writing of spectral data onto magnetic tape follows automatically. The arrangement has been used to study details of the oxidation behaviour of iron-chromium alloys as part of a larger programme of oxidation studies centred round the 18O (p,α)15 N reaction. (orig.)

  17. Origin of Knudsen forces on heated microbeams

    KAUST Repository

    Zhu, Taishan

    2010-09-09

    The presented work probes the fundamentals of Knudsen forces. Using the direct simulation Monte Carlo (DSMC) method, the flows induced by temperature inhomogeneity within a representative configuration and the Knudsen force acting on a heated microbeam are captured as functions of Knudsen number in the entire flow regime. Both flow strength and Knudsen force peak in the transition regime and negative Knudsen force absent in experimental data is observed. The mechanisms of the thermally induced flows and Knudsen forces are studied. It has been found that thermal edge flow is the main driven source for the formation of the Knudsen force on microbeams and domain configuration plays an important role in the process.

  18. Image-guided microbeam irradiation to brain tumour bearing mice using a carbon nanotube x-ray source array

    International Nuclear Information System (INIS)

    Microbeam radiation therapy (MRT) is a promising experimental and preclinical radiotherapy method for cancer treatment. Synchrotron based MRT experiments have shown that spatially fractionated microbeam radiation has the unique capability of preferentially eradicating tumour cells while sparing normal tissue in brain tumour bearing animal models. We recently demonstrated the feasibility of generating orthovoltage microbeam radiation with an adjustable microbeam width using a carbon nanotube based x-ray source array. Here we report the preliminary results from our efforts in developing an image guidance procedure for the targeted delivery of the narrow microbeams to the small tumour region in the mouse brain. Magnetic resonance imaging was used for tumour identification, and on-board x-ray radiography was used for imaging of landmarks without contrast agents. The two images were aligned using 2D rigid body image registration to determine the relative position of the tumour with respect to a landmark. The targeting accuracy and consistency were evaluated by first irradiating a group of mice inoculated with U87 human glioma brain tumours using the present protocol and then determining the locations of the microbeam radiation tracks using γ-H2AX immunofluorescence staining. The histology results showed that among 14 mice irradiated, 11 received the prescribed number of microbeams on the targeted tumour, with an average localization accuracy of 454 µm measured directly from the histology (537 µm if measured from the registered histological images). Two mice received one of the three prescribed microbeams on the tumour site. One mouse was excluded from the analysis due to tissue staining errors. (paper)

  19. Analysis and Optimization of Stability of CAS-LIBB Single Ion Microbeam

    Institute of Scientific and Technical Information of China (English)

    XU Mingliang; XU Yongjian; ZHAN Furu; CHEN Bin; CHEN Lianyun; LI Jun; YU Zengliang

    2008-01-01

    Single ion microbeam is the most advanced technology which can emit a single ion for precise localization. A single-ion microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering (LIBB),Chinese Academy of Sciences (CAS),with a spatial resolutions of about 5 #m.Based on CAS-LIBB microbeam,three key elements affecting the quality of the system axe assessed:the size of beam spot,the energy range and the counting accuracy of implanting ions.Various contributions to the ion beam stability,including the ion source,the terminal voltage of electrostatic accelerator and the components in beam pipeline,are discussed.Analysis shows that the improvement of terminal voltage stability is the most important issue for future optimization of CAS-LIBB facility.Some preliminary investigations and project aimed at optimization and development are proposed as well.

  20. Dosimetric Analyses of Single Particle Microbeam in Cell Irradiation Experiment

    Institute of Scientific and Technical Information of China (English)

    XU YongJian; JIANG Jiang; CHEN Lianyun; ZHAN Furu; YU Zengliang

    2008-01-01

    Single particle microbeam (SPM) is uniquely capable of delivering precisely the predefined number of charged particles to determined individual cells or sub-cellular targets in situ. It has been recognized as a powerful technique for unveiling ionization irradiation mechanisms of organism. This article describes some investigations on the irradiation quality of SPM of major world laboratories by means of Monte Carlo method based on dosimetry and microdosimetry. Those parameters are helpful not only to improve SPM irradiating cell experiments but also to study the biological effects of cells irradiated by SPM.

  1. High energy ion hit technique to local area using microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Ryuichi; Kamiya, Tomihiro; Suda, Tamotsu; Sakai, Takuro; Hirao, Toshio; Kobayashi, Yasuhiko; Watanabe, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    Single energetic ion hit technique has been developed as an application of ion microbeam technique, in order to study the effect of local damage or injury to materials and living organisms. The overall performance is basically defined by those of separate techniques: microbeam formation, microbeam positioning, single ion detection, detection signal processing, hit timing control, and hit verification. Recent progress on the developments of these techniques at JAERI-TIARA facility are reviewed. (author)

  2. Laser Micro-beam Manipulation System for Cells

    Institute of Scientific and Technical Information of China (English)

    孟祥旺; 李岩; 张书练; 张志诚; 赵南明

    2002-01-01

    This paper introduces a laser micro-beam system for cells manipulation. The laser micro-beam system comprises a laser scissors and a laser tweezers, which are focused by a Nd∶YAG laser and a He-Ne laser through a microscope objective, respectively. Not only the overall design of the laser micro-beam system is discussed, but also the design and choice of the critical components. A laser micro-beam system was constructed and anticipated experiment results were gained. Yeast cells can be successfully manipulated with the laser tweezers. Chromosomes can be successfully incised with the laser scissors.

  3. Parameter identification of an electrically actuated imperfect microbeam

    KAUST Repository

    Ruzziconi, Laura

    2013-12-01

    In this study we consider a microelectromechanical system (MEMS) and focus on extracting analytically the model parameters that describe its non-linear dynamic features accurately. The device consists of a clamped-clamped polysilicon microbeam electrostatically and electrodynamically actuated. The microbeam has imperfections in the geometry, which are related to the microfabrication process, resulting in many unknown and uncertain parameters of the device. The objective of the present paper is to introduce a simple but appropriate model which, despite the inevitable approximations, is able to describe and predict the most relevant aspects of the experimental response in a neighborhood of the first symmetric resonance. The modeling includes the main imperfections in the microstructure. The unknown parameters are settled via parametric identification. The approach is developed in the frequency domain and is based on matching both the frequency values and, remarkably, the frequency response curves, which are considered as the most salient features of the device response. Non-linearities and imperfections considerably complicate the identification process. Via the combined use of linear analysis and non-linear dynamic simulations, a single first symmetric mode reduced-order model is derived. Extensive numerical simulations are performed at increasing values of electrodynamic excitation. Comparison with experimental data shows a satisfactory concurrence of results not only at low electrodynamic voltage, but also at higher ones. This validates the proposed theoretical approach. We highlight its applicability, both in similar case-studies and, more in general, in systems. © 2013 Elsevier Ltd.

  4. The single-particle microbeam facility at CEA-Saclay

    Energy Technology Data Exchange (ETDEWEB)

    Khodja, H. [DSM/IRAMIS/SIS2M, CEA Saclay, F-91191 Gif-sur-Yvette Cedex (France); CNRS, UMR9956, Laboratoire Pierre Suee, F-91191 Gif-sur-Yvette Cedex (France)], E-mail: hicham.khodja@cea.fr; Hanot, M.; Carriere, M.; Hoarau, J. [DSM/IRAMIS/SIS2M, CEA Saclay, F-91191 Gif-sur-Yvette Cedex (France); CNRS, UMR9956, Laboratoire Pierre Suee, F-91191 Gif-sur-Yvette Cedex (France); Angulo, J.F. [DSV, IRCM, SRO, Laboratoire de Genetique de la Radiosensibilite, F-92265 Fontenay aux Roses (France)

    2009-06-15

    Low dose and non-targeted effect studies continue to attract the attention of a growing number of radiobiologists. Experimental setups based on light ion microbeams constitute a tool of choice for this kind of investigations. However, a careful attention must be given to experimental conditions, as setup-induced stress levels should be well below those induced by the irradiation itself. Here, we present the current status of the single-particle microbeam facility that has been developed these last years at the nuclear microprobe of Saclay. The driving idea was to build a facility in which local irradiation studies are performed in an environment close to cellular biology standards. This facility includes unique features, such as (i) a compact setup that allows easy access and vertical irradiation mode, (ii) a collimated beam that can be mechanically positioned under the desired cells at a very fast speed, avoiding the requirement of a focusing element and (iii) a controlled environment (temperature, CO{sub 2}, humidity) that allows performing of very long term experiments on cultured cells. Fluorescent techniques are implemented and permit in situ monitoring of cellular responses to irradiations. Several radiobiological studies are already underway and this will be illustrated with recent results regarding DNA damage and reactive oxygen species signaling time courses following targeted irradiations.

  5. Phase contrast image guidance for synchrotron microbeam radiotherapy

    Science.gov (United States)

    Pelliccia, Daniele; Crosbie, Jeffrey C.; Larkin, Kieran G.

    2016-08-01

    Recent image guidance developments for preclinical synchrotron microbeam radiotherapy represent a necessary step for future clinical translation of the technique. Image quality can be further improved using x-ray phase contrast, which is readily available at synchrotron facilities. We here describe a methodology for phase contrast image guidance at the Imaging and Medical Beamline at the Australian Synchrotron. Differential phase contrast is measured alongside conventional attenuation and used to improve the image quality. Post-processing based on the inverse Riesz transform is employed on the measured data to obtain noticeably sharper images. The procedure is extremely well suited for applications such as image guidance which require both visual assessment and sample alignment based on semi automatic image registration. Moreover, our approach can be combined with all other differential phase contrast imaging techniques, in all cases where a quantitative evaluation of the refractive index is not required.

  6. Phase contrast image guidance for synchrotron microbeam radiotherapy.

    Science.gov (United States)

    Pelliccia, Daniele; Crosbie, Jeffrey C; Larkin, Kieran G

    2016-08-21

    Recent image guidance developments for preclinical synchrotron microbeam radiotherapy represent a necessary step for future clinical translation of the technique. Image quality can be further improved using x-ray phase contrast, which is readily available at synchrotron facilities. We here describe a methodology for phase contrast image guidance at the Imaging and Medical Beamline at the Australian Synchrotron. Differential phase contrast is measured alongside conventional attenuation and used to improve the image quality. Post-processing based on the inverse Riesz transform is employed on the measured data to obtain noticeably sharper images. The procedure is extremely well suited for applications such as image guidance which require both visual assessment and sample alignment based on semi automatic image registration. Moreover, our approach can be combined with all other differential phase contrast imaging techniques, in all cases where a quantitative evaluation of the refractive index is not required. PMID:27436750

  7. Extreme stress gradient effects on microstructural fatigue crack propagation rates in Ni microbeams

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi-Tohidi, F.; Pierron, O. N., E-mail: olivier.pierron@me.gatech.edu [G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States)

    2015-05-18

    The fatigue crack propagation behavior of microstructurally small cracks growing under extreme stress gradients was investigated in Ni microbeams under fully reversed cyclic loading. A technique to calculate the crack growth rates in microbeams with two different normalized stress gradients (17% and 50% μm{sup −1}) is developed and validated. Decreasing crack propagation rates are observed over the first 2 μm, and the rates are more than 1 order of magnitude slower for the devices with 50% μm{sup −1} stress gradients. This fundamental knowledge is critical to predict the fatigue reliability of advanced metallic microcomponents under bending such as in microelectromechanical systems or flexible/stretchable electronics.

  8. Production of ion micro-beams

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Yasuyuki; Isoya, Akira; Arakawa, Kazuo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Tanaka, Ryuichi [Ion Beam Irradiation Service Limited Company, Takasaki, Gunma (Japan)

    2001-02-01

    This is a short summary on the test fabrication and performance testing. Here micro-beams are understood as beams in diameter smaller than 0.01 {mu} m. We had made a choice of the combination, of the focusing action with a single hole lens, and of the focusing and acceleration actions with a uniform electrostatic field between the electrodes. Measurements has been repeated of the beam radius with a moving knifedge. The spatial resolution now reaches 0.05 {mu} m. (M. Tanaka)

  9. Comparison of two methods for measuring γ-H2AX nuclear fluorescence as a marker of DNA damage in cultured human cells: applications for microbeam radiation therapy

    International Nuclear Information System (INIS)

    Microbeam radiation therapy (MRT) delivers single fractions of very high doses of synchrotron x-rays using arrays of microbeams. In animal experiments, MRT has achieved higher tumour control and less normal tissue toxicity compared to single-fraction broad beam irradiations of much lower dose. The mechanism behind the normal tissue sparing of MRT has yet to be fully explained. An accurate method for evaluating DNA damage, such as the γ-H2AX immunofluorescence assay, will be important for understanding the role of cellular communication in the radiobiological response of normal and cancerous cell types to MRT. We compare two methods of quantifying γ-H2AX nuclear fluorescence for uniformly irradiated cell cultures: manual counting of γ-H2AX foci by eye, and an automated, MATLAB-based fluorescence intensity measurement. We also demonstrate the automated analysis of cell cultures irradiated with an array of microbeams. In addition to offering a relatively high dynamic range of γ-H2AX signal versus irradiation dose ( > 10 Gy), our automated method provides speed, robustness, and objectivity when examining a series of images. Our in-house analysis facilitates the automated extraction of the spatial distribution of the γ-H2AX intensity with respect to the microbeam array — for example, the intensities in the peak (high dose area) and valley (area between two microbeams) regions. The automated analysis is particularly beneficial when processing a large number of samples, as is needed to systematically study the relationship between the numerous dosimetric and geometric parameters involved with MRT (e.g., microbeam width, microbeam spacing, microbeam array dimensions, peak dose, valley dose, and geometric arrangement of multiple arrays) and the resulting DNA damage.

  10. Genome-wide transcription responses to synchrotron microbeam radiotherapy.

    Science.gov (United States)

    Sprung, Carl N; Yang, Yuqing; Forrester, Helen B; Li, Jason; Zaitseva, Marina; Cann, Leonie; Restall, Tina; Anderson, Robin L; Crosbie, Jeffrey C; Rogers, Peter A W

    2012-10-01

    The majority of cancer patients achieve benefit from radiotherapy. A significant limitation of radiotherapy is its relatively low therapeutic index, defined as the maximum radiation dose that causes acceptable normal tissue damage to the minimum dose required to achieve tumor control. Recently, a new radiotherapy modality using synchrotron-generated X-ray microbeam radiotherapy has been demonstrated in animal models to ablate tumors with concurrent sparing of normal tissue. Very little work has been undertaken into the cellular and molecular mechanisms that differentiate microbeam radiotherapy from broad beam. The purpose of this study was to investigate and compare the whole genome transcriptional response of in vivo microbeam radiotherapy versus broad beam irradiated tumors. We hypothesized that gene expression changes after microbeam radiotherapy are different from those seen after broad beam. We found that in EMT6.5 tumors at 4-48 h postirradiation, microbeam radiotherapy differentially regulates a number of genes, including major histocompatibility complex (MHC) class II antigen gene family members, and other immunity-related genes including Ciita, Ifng, Cxcl1, Cxcl9, Indo and Ubd when compared to broad beam. Our findings demonstrate molecular differences in the tumor response to microbeam versus broad beam irradiation and these differences provide insight into the underlying mechanisms of microbeam radiotherapy and broad beam.

  11. PREFACE: European Microbeam Analysis Society's 14th European Workshop on Modern Developments and Applications in Microbeam Analysis (EMAS 2015), Portorož, Slovenia, 3-7 May 2015

    Science.gov (United States)

    Llovet, Xavier; Matthews, Michael B.; Čeh, Miran; Langer, Enrico; Žagar, Kristina

    2016-02-01

    This volume of the IOP Conference Series: Materials Science and Engineering contains papers from the 14th Workshop of the European Microbeam Analysis Society (EMAS) on Modern Developments and Applications in Microbeam Analysis which took place from the 3rd to the 7th of May 2015 in the Grand Hotel Bernardin, Portorož, Slovenia. The primary aim of this series of workshops is to assess the state-of-the-art and reliability of microbeam analysis techniques. The workshops also provide a forum where students and young scientists starting out on a career in microbeam analysis can meet and discuss with the established experts. The workshops have a unique format comprising invited plenary lectures by internationally recognized experts, poster presentations by the participants and round table discussions on the key topics led by specialists in the field.This workshop was organized in collaboration with the Jožef Stefan Institute and SDM - Slovene Society for Microscopy. The technical programme included the following topics: electron probe microanalysis, STEM and EELS, materials applications, cathodoluminescence and electron backscatter diffraction (EBSD), and their applications. As at previous workshops there was also a special oral session for young scientists. The best presentation by a young scientist was awarded with an invitation to attend the 2016 Microscopy and Microanalysis meeting at Columbus, Ohio. The prize went to Shirin Kaboli, of the Department of Metals and Materials Engineering of McGill University (Montréal, Canada), for her talk entitled "Electron channelling contrast reconstruction with electron backscattered diffraction". The continuing relevance of the EMAS workshops and the high regard in which they are held internationally can be seen from the fact that 71 posters from 16 countries were on display at the meeting and that the participants came from as far away as Japan, Canada, USA, and Australia. A selection of participants with posters was invited

  12. Comparison of proton microbeam and gamma irradiation for the radiation hardness testing of silicon PIN diodes

    Science.gov (United States)

    Jakšić, M.; Grilj, V.; Skukan, N.; Majer, M.; Jung, H. K.; Kim, J. Y.; Lee, N. H.

    2013-09-01

    Simple and cost-effective solutions using Si PIN diodes as detectors are presently utilized in various radiation-related applications in which excessive exposure to radiation degrades their charge transport properties. One of the conventional methods for the radiation hardness testing of such devices is time-consuming irradiation with electron beam or gamma-ray irradiation facilities, high-energy proton accelerators, or with neutrons from research reactors. Recently, for the purpose of radiation hardness testing, a much faster nuclear microprobe based approach utilizing proton irradiation has been developed. To compare the two different irradiation techniques, silicon PIN diodes have been irradiated with a Co-60 gamma radiation source and with a 6 MeV proton microbeam. The signal degradation in the silicon PIN diodes for both irradiation conditions has been probed by the IBIC (ion beam induced charge) technique, which can precisely monitor changes in charge collection efficiency. The results presented are reviewed on the basis of displacement damage calculations and NIEL (non-ionizing energy loss) concept.

  13. [Progress in application of microbeam X-ray fluorescence spectroscopy in forensic science].

    Science.gov (United States)

    Su, Hui-Fang; Liu, Chao; Hu, Sun-Lin; Wang, Song-Cai; Sun, Li-Min; Huang, Wei; Zhang, Xiao-Ting; Li, Shuang-Lin

    2013-02-01

    Microbeam X-ray fluorescence (micro-XRF) spectrometry has been raised as an analytical technique of microbeam during the recent years. With its advantages of high sensitivity, small sample requirement, high testing accuracy and non-destruction, the technique is widely utilized in forensic science. This review bases on recent researches at home and abroad, describes its applications including identification of gunshot residue, visualization of fingerprints, discrimination of drug source, production process, and other material evidences of analysis in crime scene. Thanks to the advances in technology, intelligent and portable micro-XRF equipment has appeared to be applied. It is believed that it may be more popular and frequent in administration of forensic science in the near future.

  14. High resolution 3D imaging of synchrotron generated microbeams

    Energy Technology Data Exchange (ETDEWEB)

    Gagliardi, Frank M., E-mail: frank.gagliardi@wbrc.org.au [Alfred Health Radiation Oncology, The Alfred, Melbourne, Victoria 3004, Australia and School of Medical Sciences, RMIT University, Bundoora, Victoria 3083 (Australia); Cornelius, Iwan [Imaging and Medical Beamline, Australian Synchrotron, Clayton, Victoria 3168, Australia and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales 2500 (Australia); Blencowe, Anton [Division of Health Sciences, School of Pharmacy and Medical Sciences, The University of South Australia, Adelaide, South Australia 5000, Australia and Division of Information Technology, Engineering and the Environment, Mawson Institute, University of South Australia, Mawson Lakes, South Australia 5095 (Australia); Franich, Rick D. [School of Applied Sciences and Health Innovations Research Institute, RMIT University, Melbourne, Victoria 3000 (Australia); Geso, Moshi [School of Medical Sciences, RMIT University, Bundoora, Victoria 3083 (Australia)

    2015-12-15

    Purpose: Microbeam radiation therapy (MRT) techniques are under investigation at synchrotrons worldwide. Favourable outcomes from animal and cell culture studies have proven the efficacy of MRT. The aim of MRT researchers currently is to progress to human clinical trials in the near future. The purpose of this study was to demonstrate the high resolution and 3D imaging of synchrotron generated microbeams in PRESAGE® dosimeters using laser fluorescence confocal microscopy. Methods: Water equivalent PRESAGE® dosimeters were fabricated and irradiated with microbeams on the Imaging and Medical Beamline at the Australian Synchrotron. Microbeam arrays comprised of microbeams 25–50 μm wide with 200 or 400 μm peak-to-peak spacing were delivered as single, cross-fire, multidirectional, and interspersed arrays. Imaging of the dosimeters was performed using a NIKON A1 laser fluorescence confocal microscope. Results: The spatial fractionation of the MRT beams was clearly visible in 2D and up to 9 mm in depth. Individual microbeams were easily resolved with the full width at half maximum of microbeams measured on images with resolutions of as low as 0.09 μm/pixel. Profiles obtained demonstrated the change of the peak-to-valley dose ratio for interspersed MRT microbeam arrays and subtle variations in the sample positioning by the sample stage goniometer were measured. Conclusions: Laser fluorescence confocal microscopy of MRT irradiated PRESAGE® dosimeters has been validated in this study as a high resolution imaging tool for the independent spatial and geometrical verification of MRT beam delivery.

  15. Microbeam Irradiation of C. elegans Nematode in Microfluidic Channels

    OpenAIRE

    M. Buonanno; Garty, G.; Grad, M.; Gendrel, M.; Hobert, O.; Brenner, D J

    2013-01-01

    To perform high-throughput studies on the biological effects of ionizing radiation in vivo, we have implemented a microfluidic tool for microbeam irradiation of Caenorhabditis elegans. The device allows the immobilization of worms with minimal stress for a rapid and controlled microbeam irradiation of multiple samples in parallel. Adapted from an established design, our microfluidic clamp consists of 16 tapered channels with 10-μm thin bottoms to ensure charged particle traversal. Worms are i...

  16. Wide area scanning system and carbon microbeams at the external microbeam facility of the INFN LABEC laboratory in Florence

    Science.gov (United States)

    Giuntini, L.; Massi, M.; Calusi, S.; Castelli, L.; Carraresi, L.; Fedi, M. E.; Gelli, N.; Liccioli, L.; Mandò, P. A.; Mazzinghi, A.; Palla, L.; Romano, F. P.; Ruberto, C.; Taccetti, F.

    2015-04-01

    Recently, developments have been made to the external scanning microbeam of INFN-LABEC laboratory in Florence. A new system for mechanical sample scanning was implemented. This system allows us to acquire large maps (up to 20 × 20 cm2), of great interest in the Cultural Heritage field. In parallel, the possibility of using carbon microbeams for experiments, such as, for example, ion beam modification of materials and MeV Secondary Ion Mass Spectrometry, has been investigated. As a test application, Particle Induced X-ray Emission with carbon microbeams has been performed on a lapis lazuli stone. First results for both wide area imaging and external carbon microbeams are briefly reported.

  17. Wide area scanning system and carbon microbeams at the external microbeam facility of the INFN LABEC laboratory in Florence

    Energy Technology Data Exchange (ETDEWEB)

    Giuntini, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Massi, M. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Calusi, S. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Castelli, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Carraresi, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Fedi, M.E.; Gelli, N. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Liccioli, L.; Mandò, P.A.; Mazzinghi, A. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Palla, L. [INFN, Sezione di Pisa and Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa (Italy); Romano, F.P. [Consiglio Nazionale delle Ricerche (CNR), Istituto per i Beni Archeologici e Monumentali (IBAM), Via Biblioteca, 4, 95124 Catania (Italy); Istituto Nazionale di Fisica Nucleare (INFN), LNS, Via S.Sofia 62, 95125 Catania (Italy); and others

    2015-04-01

    Recently, developments have been made to the external scanning microbeam of INFN-LABEC laboratory in Florence. A new system for mechanical sample scanning was implemented. This system allows us to acquire large maps (up to 20 × 20 cm{sup 2}), of great interest in the Cultural Heritage field. In parallel, the possibility of using carbon microbeams for experiments, such as, for example, ion beam modification of materials and MeV Secondary Ion Mass Spectrometry, has been investigated. As a test application, Particle Induced X-ray Emission with carbon microbeams has been performed on a lapis lazuli stone. First results for both wide area imaging and external carbon microbeams are briefly reported.

  18. Proceedings of 6th International Microbeam Workshop/12th L.H. Gray Workshop Microbeam Probes of Cellular Radiation Response

    International Nuclear Information System (INIS)

    The extended abstracts which are submitted here present a summary of the proceedings of the 6th International Workshop/12th LH Gray Workshop: Microbeam Probes of Cellular Radiation Response, held at St. Catherine's College, University of Oxford, UK on March, 29th-31st, 2003. In 1993 the 4th LH Gray Workshop entitled ''Microbeam Probes of Cellular Radiation Response'' was held at the Gray Cancer Institute in Northwood. This was organized by Prof BD Michael, Dr M. Folkard and Dr KM Prise and brought together 40 participants interested in developing and applying new microbeam technology to problems in radiation biology (1). The workshop was an undoubted success and has spawned a series of subsequent workshops every two years. In the past, these workshops have been highly successful in bringing together groups interested in developing and applying micro-irradiation techniques to the study of cell and tissue damage by ionizing radiations. Following the first microbeam workshop, there has been a rapid growth in the number of centres developing radiobiology microbeams, or planning to do so and there are currently 15-20 worldwide. Much of the recent research using microbeams has used them to study low-dose effects and ''non-targeted'' responses such bystander effects, genomic instability and adaptive responses. The goal of the 6th workshop was to build on our knowledge of the development of microbeam approaches and the application to radiation biology in the future with the meeting stretching over a 3 day period. Over 80 participants reviewed the current state of radiobiology microbeam research worldwide and reported on new technological developments both in the fields of physics and biology

  19. Dynamics of a clamped–clamped microbeam resonator considering fabrication imperfections

    KAUST Repository

    Bataineh, Ahmad M.

    2014-10-18

    We present an investigation into the static and dynamic behavior of an electrostatically actuated clamped–clamped polysilicon microbeam resonator accounting for its fabrication imperfections, which are commonly encountered in similar microstructures. These are mainly because of the initial deformation of the beam due to stress gradient and its flexible anchors. First, we show experimental data of the microbeam when driven electrically by varying the amplitude and frequency of the voltage loads. The results reveal several interesting nonlinear phenomena of jumps, hysteresis, and softening behaviors. Theoretical investigation is then conducted to model the microbeam, and hence, interpret the experimental data. We solve the Eigen value problem governing the natural frequencies analytically. We then utilize a Galerkin-based procedure to derive a reduced order model, which is then used to simulate both the static and dynamic responses. To achieve good matching between theory and experiment, we show that the exact profile of the deformed beam needs to be utilized in the reduced order model, as measured from the optical profiler, combined with a shooting technique simulation, which is capable of tracing the resonant frequency branches under very-low damping conditions.

  20. WE-E-BRE-06: High-Dose Microbeam Radiation Induces Different Responses in Tumor Microenvironment Compared to Conventional Seamless Radiation in Window Chamber Tumor Models

    Energy Technology Data Exchange (ETDEWEB)

    Chang, S; Zhang, J; Hadsell, M [UNC School of Medicine, Chapel Hill, NC (United States); Fontanella, A; Schroeder, T; Palmer, G; Dewhirst, M [Duke University, Durham, NC (United States); Boss, M [North Carolina State University, Raleigh, NC (United States); Berman, K [School of Veterinary Medicine, University of Glasgow, Glasgow, Scotland (United Kingdom)

    2014-06-15

    Purpose: Microbeam radiation therapy and GRID therapy are different forms of Spatially-Fractioned Radiation Therapy (SFRT) that is fundamentally different from the conventional seamless and temporally fractionated radiation therapy. SFRT is characterized by a ultra-high dose (10s –100s Gy) dose single treatment with drastic inhomogeneity pattern of given spatial frequencies. Preclinical and limited clinical studies have shown that the SFRT treatments may offer significant improvements in reducing treatment toxicity, especially for those patients who have not benefited from the state-of-the-art radiation therapy approaches. This preliminary study aims to elucidate the underlying working mechanisms of SFRT, which currently remains poorly understood. Methods: A genetically engineered 4T1 murine mammary carcinoma cell line and nude mice skin fold window chamber were used. A nanotechnology-based 160kV x-ray irradiator delivered 50Gy (entrance dose) single treatments of microbeam or seamless radiation. Animals were in 3 groups: mock, seamless radiation, and 300μm microbeam radiation. The windows were imaged using a hyperspectral system to capture total hemoglobin/saturation, GFP fluorescence emission, RFP fluorescence emission, and vessel density at 9 time points up to 7 days post radiation. Results: We found unique physiologic changes in different tumor/normal tissue regions and differential effects between seamless and microbeam treatments. They include 1) compared to microbeam and mock radiation seamless radiation damaged more microvasculature in tumor-surrounding normal tissue, 2) a pronounced angiogenic effect was observed with vascular proliferation in the microbeam irradiated portion of the tumor days post treatment (no such effect observed in seamless and mock groups), and 3) a notable change in tumor vascular orientation was observed where vessels initially oriented parallel to the beam length were replaced by vessels running perpendicular to the irradiation

  1. MFM and PEEM observation of micrometre-sized magnetic dot arrays fabricated by ion-microbeam irradiation in FeRh thin films

    Energy Technology Data Exchange (ETDEWEB)

    Aikoh, K.; Tohki, A. [Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531 (Japan); Matsui, T., E-mail: t-matsui@21c.osakafu-u.ac.jp [Osaka Pefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531 (Japan); Iwase, A. [Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531 (Japan); Satoh, T.; Takano, K.; Kohka, M.; Saitoh, Y.; Kamiya, T. [Japan Atomic Energy Agency, Takasaki, Gumma 370-1292 (Japan); Ohkochi, T. [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198 (Japan); Kotsugi, M. [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198 (Japan); CREST-JST, Kawaguchi, Saitama 332-0012 (Japan); Nakamura, T. [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198 (Japan); Kinoshita, T. [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198 (Japan); CREST-JST, Kawaguchi, Saitama 332-0012 (Japan)

    2012-03-01

    Micrometre-size lateral magnetic modulations were fabricated in FeRh thin films by ion-microbeam irradiation. Their magnetic domain structures were characterized by XMCD–PEEM. FeRh thin films were irradiated with a 10 MeV iodine ion microbeam to produce micrometre-scale ferromagnetic microstructures by modifying the local magnetic character from antiferromagnetism to ferromagnetism using ion-microbeam irradiation. Two-dimensional magnetic dot arrays of dimensions ∼2 µm × 4 µm as well as 10 µm × 10 µm were successfully produced on the FeRh surface, which was confirmed by magnetic force microscopy (MFM). The results of photoemission electron microscopy (PEEM) combined with X-ray magnetic circular dichroism reveal that the easy axis of the magnetization of the ion-beam-irradiated ferromagnetism in the FeRh thin films lies in the film planes along the 〈001〉 direction of the MgO substrates.

  2. MFM and PEEM observation of micrometre-sized magnetic dot arrays fabricated by ion-microbeam irradiation in FeRh thin films

    OpenAIRE

    Aikoh, K.; Tohki, A.; T. Matsui; Iwase, A.; Satoh, T.; Takano, K; Kohka, M.; Saitoh, Y.; Kamiya, T; Ohkochi, T.; Kotsugi, M.; Nakamura, T.(International Center for Elementary Particle Physics and Department of Physics, The University of Tokyo, Tokyo, Japan); Kinoshita, T.

    2012-01-01

    FeRh thin films were irradiated with a 10 MeV iodine ion microbeam to produce micrometre-scale ferromagnetic microstructures by modifying the local magnetic character from antiferromagnetism to ferromagnetism using ion-microbeam irradiation. Two-dimensional magnetic dot arrays of dimensions ∼2 µm × 4 µm as well as 10 µm × 10 µm were successfully produced on the FeRh surface, which was confirmed by magnetic force microscopy (MFM). The results of photoemission electron microscopy (PEEM) combine...

  3. Characterization of Zircaloy-4 corrosion films using microbeam synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Spengler, David J., E-mail: dspen5106@gmail.com [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Motta, Arthur T. [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Bajaj, Ram; Seidensticker, John R. [Bettis Atomic Power Laboratory, 814 Pittsburgh-McKeesport Blvd., West Mifflin, PA 15122 (United States); Cai, Zhonghou [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2015-09-15

    A study of the oxide layers formed in 360 °C and 316 °C water on Zircaloy-4 samples has been performed in an attempt to help answer fundamental questions about oxide protectiveness, growth mechanisms, and the nature of oxide growth during autoclave corrosion. Two different oxide thicknesses – 12 and 39.5 μm – were investigated. Microbeam synchrotron radiation diffraction and fluorescence techniques with an X-ray beam size of 0.2 μm were used to characterize oxide in cross sections to determine the oxide phase content, grain size, texture, and orientation relationships as a function of through-thickness from the oxide–metal interface. The results confirm that the oxide is comprised primarily of monoclinic ZrO{sub 2}, with tetragonal ZrO{sub 2} present in small amounts. The observed diffraction peaks are consistent with monoclinic phases having a strong fiber texture with the 200{sub m} plane aligned with the oxide–metal interface, and with the 011{sub m} plane closely aligned with the transverse-normal (T) plane. The fraction of bulk tetragonal phase increased in the region located within one transition thickness near the oxide–metal interface. A strong periodicity was seen in oxide intensity from both the monoclinic and tetragonal phases corresponding to an oxide transition thickness of 1.8–1.9 μm. The grain size of the tetragonal phase was determined to be smaller than the monoclinic phase, and the grain size for the monoclinic phase decreased starting at a distance of approximately one transition layer from the oxide–metal interface. The relative amounts of monoclinic peak broadening due to strain and grain size were calculated, the former being approximately constant, while the latter decreased with increasing distance from the oxide–metal interface, corresponding to an increase in grain size. These findings are compared to previously performed microbeam diffraction experiments on Zircaloy-4 and other Zr-based alloys.

  4. Negative Knudsen force on heated microbeams

    KAUST Repository

    Zhu, Taishan

    2011-11-18

    Knudsen force acting on a heated microbeam adjacent to a cold substrate in a rarefied gas is a mechanical force created by unbalanced thermal gradients. The measured force has its direction pointing towards the side with a lower thermal gradient and its magnitude vanishes in both continuum and free-molecule limits. In our previous study, negative Knudsen forces were discovered at the high Knudsen regime before diminishing in the free-molecule limit. Such a phenomenon was, however, neither observed in experiment [A. Passian et al., Phys. Rev. Lett. 90, 124503 (2003)], nor captured in the latest numerical study [J. Nabeth et al., Phys. Rev. E 83, 066306 (2011)]. In this paper, the existence of such a negative Knudsen force is further confirmed using both numerical simulation and theoretical analysis. The asymptotic order of the Knudsen force near the collisionless limit is analyzed and the analytical expression of its leading term is provided, from which approaches for the enhancement of negative Knudsen forces are proposed. The discovered phenomenon could find its applications in novel mechanisms for pressure sensing and actuation.

  5. Consideration about the Single-neutron Microbeam Facility

    Institute of Scientific and Technical Information of China (English)

    吴瑜; 王绍虎; 余增亮

    2004-01-01

    A conception of the single-neutron microbeam facility was put forward in this paper.The specific particle (e.g. H+, 2d+ or α ) bombarding a specific target can generate neutron,when the particle energy is more than a threshold (e.g., H+ energy is more than 2 MeV). And if the specific beam spot on the target is very small, the neutron beam along the direction of the specific beam spot will be very small too. If the neutron beam is weak and a neutron detector is mounted after the specific neutron collimator, the single- neutron will be obtained. Therefore,if the specific target and the neutron detector are installed after the proton accelerator and the microbeam system, the single-neutron microbeam will probably be obtained.

  6. Quantitative Single-Ion Irradiation by ASIPP Microbeam

    Institute of Scientific and Technical Information of China (English)

    WANG Xu-Fei; WU Yu; XU Ming-Liang; WU Li-Jun; WANG Shao-Hu; YU Zeng-Liang; CHEN Lian-Yun; HU Zhi-Wen; WANG Xiao-Hua; ZHANG Jun; LI Jun; CHEN Bin; HU Su-Hua; SHI Zhong-Tao

    2004-01-01

    @@ A single-ion microbeam facility has been constructed by the microbeam research group in ASIPP (Institute of Plasma Physics, Chinese Academy of Science). The system was designed to deliver defined numbers of hydrogen ions produced by a van de Graaff accelerator, covering an energy range from 200keV to 3 MeV, into living cells(5 μm-20 μm diameter) growing in culture on thin plastic films. The beam is collimated by a 1- μm inner diameter HPLC (high performance liquid chromatography) capillary, which forms the micron-dimensional beam-line exit.A microbeam collimator, a scintillation ion counting system and a fast beam shutter, which constitute a precise dosage measuring and controlling system, jointly perform quantitative single-ion irradiation. With this facility,we can presently acquire ion-hitting efficiency close to 95%.

  7. Dynamics of an Imperfect Microbeam Considering its Exact Shape

    KAUST Repository

    Bataineh, Ahmad M.

    2014-08-17

    We study the static and dynamic behavior of electrically actuated micromachined arches. First, we conduct experiments on micromachined polysilicon beams by driving them electrically and varying their amplitude and frequency of voltage loads. The results reveal several interesting nonlinear phenomena of jumps, hysteresis, and softening behaviors. Next, we conduct analytical and theoretical investigation to understand the experiments. First, we solve the Eigen value problem analytically. We study the effect of the initial rise on the natural frequency and mode shapes, and use a Galerkin-based procedure to derive a reduced order model, which is then used to solve both the static and dynamic responses. We use two symmetric modes in the reduced order model to have accurate and converged results. We use long time integration to solve the nonlinear ordinary differential equations, and then modify our model using effective length to match experimental results. To further improve the matching with the experimental data, we curve-fit the exact profile of the microbeam to match the experimentally measured profile and use it in the reduced-order model to generate frequency-response curves. Finally, we use another numerical technique, the shooting technique, to solve the nonlinear ordinary differential equations. By using shooting and the curve fitted function, we found that we get good agreement with the experimental data.

  8. Analysis of Frequency Spectrum of Laser-Induced Vibration of Microbeam Resonators

    Institute of Scientific and Technical Information of China (English)

    FANG Dai-Ning; SUN Yu-xin; SOH Ai-Kah

    2006-01-01

    The vibration phenomenon during pulsed laser heating of micro-beams is investigated.The beam is made of silicon and js heated by a laser pulse with a non-Gaussian temporal profile and with an ultrashort pulse duration of 2ps.which incites vibration due to the thermoelastic damping effect.This coupled thermoelastic problem is solved using an analytical-numerical technique based on the Laplace transformation.The damping ratio and resonant frequency shift ratio of beams due t0 the air damping effect and the thermoelastic damping ettect are also examined and discusssed.

  9. The first interdisciplinary experiments at the IMP high energy microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Du, Guanghua; Guo, Jinlong; Wu, Ruqun; Guo, Na; Liu, Wenjing; Ye, Fei; Sheng, Lina; Li, Qiang [Institute of Modern Physics (IMP), Chinese Academy of Sciences, Lanzhou (China); Li, Huiyun [Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen (China)

    2015-04-01

    The high energy beam of tens to hundred MeV/u ions possesses mm-to-cm penetration depth in materials and can be easily extracted into air without significant energy loss and beam scattering. Combination of high energy ions and microbeam technology facilitates the microprobe application to many practical studies in large scale samples. The IMP heavy ion microbeam facility has recently been integrated with microscopic positioning and targeting irradiation system. This paper introduced the first interdisciplinary experiments performed at the IMP microbeam facility using the beam of 80.5 MeV/u carbon ions. Bystander effect induction via medium transferring was not found in the micro-irradiation study using HeLa cells. The mouse irradiation experiment demonstrated that carbon irradiation of 10 Gy dose to its tuberomammillary nucleus did not impair the sleep nerve system. The fault injection attack on RSA (Rivest–Shamir–Adleman) decryption proved that the commercial field-programmable gate array chip is vulnerable in single event effect to low linear-energy-transfer carbon irradiation, and the attack can cause the leakage of RSA private key. This work demonstrates the potential of high energy microbeam in its application to biology, biomedical, radiation hardness, and information security studies.

  10. The first interdisciplinary experiments at the IMP high energy microbeam

    International Nuclear Information System (INIS)

    The high energy beam of tens to hundred MeV/u ions possesses mm-to-cm penetration depth in materials and can be easily extracted into air without significant energy loss and beam scattering. Combination of high energy ions and microbeam technology facilitates the microprobe application to many practical studies in large scale samples. The IMP heavy ion microbeam facility has recently been integrated with microscopic positioning and targeting irradiation system. This paper introduced the first interdisciplinary experiments performed at the IMP microbeam facility using the beam of 80.5 MeV/u carbon ions. Bystander effect induction via medium transferring was not found in the micro-irradiation study using HeLa cells. The mouse irradiation experiment demonstrated that carbon irradiation of 10 Gy dose to its tuberomammillary nucleus did not impair the sleep nerve system. The fault injection attack on RSA (Rivest–Shamir–Adleman) decryption proved that the commercial field-programmable gate array chip is vulnerable in single event effect to low linear-energy-transfer carbon irradiation, and the attack can cause the leakage of RSA private key. This work demonstrates the potential of high energy microbeam in its application to biology, biomedical, radiation hardness, and information security studies

  11. Dynamic Characteristics of Electrostatically Actuated Shape Optimized Variable Geometry Microbeam

    Directory of Open Access Journals (Sweden)

    Sha Zhang

    2015-01-01

    Full Text Available We mainly analyze the dynamic characteristics of electrostatically actuated shape optimized variable geometry microbeam. A nonlinear dynamic model considering midplane stretching, electrostatic force, and electrical field fringing effects is developed. Firstly, we study the static responses of the optimized microbeams under DC polarization voltage. The generalized differential quadrature method (GDQM is used. Secondly, the dynamic responses of the shape optimized microbeams driven by DC and AC voltages are investigated using GDQM in conjunction with Levenberg-Marquardt optimization method. The results show that the more gradual change in width, the larger the resonant frequency and the maximum amplitude at resonance. Then we further discuss in detail how do the maximum width, midsection width, and curvature of the width function affect the frequency response of the microbeams. We find that the amplitude and resonant frequency of the dynamic response are not monotonically increasing as the curvature of the width function increases and there exists a critical curvature. This analysis will be helpful in the optimal design of MEMS actuators. Finally, for more consideration, different residual stress, squeeze-film damping, and fringing effect models are introduced into the governing equation of motion and we compare the corresponding dynamic response.

  12. PREFACE: EMAS 2013 Workshop: 13th European Workshop on Modern Developments and Applications in Microbeam Analysis

    Science.gov (United States)

    Llovet, Xavier, Dr; Matthews, Mr Michael B.; Brisset, François, Dr; Guimarães, Fernanda, Dr; Vieira, Professor Joaquim M., Dr

    2014-03-01

    This volume of the IOP Conference Series: Materials Science and Engineering contains papers from the 13th Workshop of the European Microbeam Analysis Society (EMAS) on Modern Developments and Applications in Microbeam Analysis which took place from the 12th to the 16th of May 2013 in the Centro de Congressos do Alfândega, Porto, Portugal. The primary aim of this series of workshops is to assess the state-of-the-art and reliability of microbeam analysis techniques. The workshops also provide a forum where students and young scientists starting out on a career in microbeam analysis can meet and discuss with the established experts. The workshops have a very specific format comprising invited plenary lectures by internationally recognized experts, poster presentations by the participants and round table discussions on the key topics led by specialists in the field. This workshop was organized in collaboration with LNEG - Laboratório Nacional de Energia e Geologia and SPMICROS - Sociedade Portuguesa de Microscopia. The technical programme included the following topics: electron probe microanalysis, future technologies, electron backscatter diffraction (EBSD), particle analysis, and applications. As at previous workshops there was also a special oral session for young scientists. The best presentation by a young scientist was awarded with an invitation to attend the 2014 Microscopy and Microanalysis meeting at Hartford, Connecticut. The prize went to Shirin Kaboli, of the Department of Metals and Materials Engineering of McGill University (Montréal, Canada), for her talk entitled ''Plastic deformation studies with electron channelling contrast imaging and electron backscattered diffraction''. The continuing relevance of the EMAS workshops and the high regard in which they are held internationally can be seen from the fact that 74 posters from 21 countries were on display at the meeting and that the participants came from as far away as Japan, Canada and the USA. A

  13. An Evaluation of Dose Equivalence between Synchrotron Microbeam Radiation Therapy and Conventional Broadbeam Radiation Using Clonogenic and Cell Impedance Assays

    OpenAIRE

    Mohammad Johari Ibahim; Crosbie, Jeffrey C.; Yuqing Yang; Marina Zaitseva; Andrew W Stevenson; Rogers, Peter A. W.; Premila Paiva

    2014-01-01

    BACKGROUND: High-dose synchrotron microbeam radiation therapy (MRT) has shown the potential to deliver improved outcomes over conventional broadbeam (BB) radiation therapy. To implement synchrotron MRT clinically for cancer treatment, it is necessary to undertake dose equivalence studies to identify MRT doses that give similar outcomes to BB treatments. AIM: To develop an in vitro approach to determine biological dose equivalence between MRT and BB using two different cell-based assays. METHO...

  14. WE-G-BRE-01: A High Power Nanotube X-Ray Microbeam Irradiator for Preclinical Brain Tumor Treatment

    International Nuclear Information System (INIS)

    Purpose: Microbeam radiation therapy (MRT) is a new type of cancer treatment undergoing studies at various synchrotron facilities. The principle of MRT is using arrays of microscopically small, low-energy X-radiation for the treatment of various radio-resistant, deep-seated tumors. Our motivation is to develop a compact and inexpensive image guided MRT irradiator to use in the research lab setting. After a successful initial demonstration, here we report a second generation carbon nanotube (CNT) cathode based MRT tube, capable of producing multiple microbeam lines with an anticipated dose rate of 11 Gy/min per line. Methods: The system uses multiple line CNT source arrays to generate multiple focal lines on the anode. The increase in dose-rate, compared to our first generation system, is achieved by increasing the operating voltage from 160 kVp to 225kVp, adding multiple simultaneous focal lines on the anode, and a more efficient cooling mechanism using a 6kW oil-cooled anode. Results: This work will present the design and development process, challenges and solutions to meeting operating specifications, and the final design of the tube and collimator, along with optimization and stabilization of its use. A detailed characterization of its capabilities will be included with a comprehensive measurement of its X-ray focal line dimensions, an evaluation of its collimator alignment and microbeam dimensions, and phantom-based quantification of its dosimetric output. Conclusion: The development of a second generation, compact, multiple line MRT device using carbon nanotube (CNT) cathode based X-ray technology and a novel oil cooled anode design is presented here. With this new source, we are capable of delivering a total microbeam radiation dose comparable to the low end of the synchrotron based MRT systems for small animal brain tumor models

  15. A software tool enabling the analysis of small lateral features without the use of a micro-beam

    Science.gov (United States)

    Healy, M. J. F.; Torres, M.; Painter, J. D.

    2006-08-01

    A new method is developed that allows samples whose composition varies rapidly across the surface, such as actual microelectronic devices, to be composition depth profiled without the use of a micro-beam or other special equipment. This is achieved by extending the traditional simulation method to an extra dimension where lateral position is also accommodated. The tool is a software shell to SIMNRA [M. Mayer, SIMNRA User's Guide, Report IPP 9/113, Max-Planck-Institut fur Plasmaphysik, Garching, Germany, 1997] that allows a multi-dimensional model of the sample to be created, simulated and iterated towards experiment. It is demonstrated on a silicon dioxide coated wafer embedded with narrowly spaced sub-micron wide metal tracks probed with a conventional beam-spot of millimetre proportions, and is supported by electron microscopy studies. The software shell also eases the analysis of laterally homogeneous samples where complementary ion beam analysis techniques must be employed by allowing a single model to control multiple simulations based on different geometries or techniques.

  16. PREFACE: EMAS 2011: 12th European Workshop on Modern Developments in Microbeam Analysis

    Science.gov (United States)

    Brisset, François; Dugne, Olivier; Robaut, Florence; Lábár, János L.; Walker, Clive T.

    2012-03-01

    presentation of their work in three dedicated sessions. The prize for the best poster was an invitation to participate in the 22nd Australian Conference on Microscopy and Microanalysis (ACMM 22) at Perth, Western Australia. The prize was awarded to G Samardzija of the Jozef Stefan Institute, Ljubljana, for the poster entitled: 'EPMA-WDS quantitative compositional analysis of barium titanate ceramics doped with cerium'. This proceedings volume contains the full texts of 5 of the invited plenary lectures and of 23 papers on related topics originating from the posters presented at the workshop. All the papers have been subjected to peer review by a least two referees. January 2012 Acknowledgements On behalf of the European Microbeam Analysis Society I would like to thank all the invited speakers, session chairs and members of the discussion panels for making the meeting such a great success. Special thanks go to François Brisset and Luc Van't dack who directed the organisation of the workshop giving freely of their time and talents. As was the case for previous workshops, the EMAS board in corpore was responsible for the scientific programme. The technical exhibition, which occupied 130 sq.m of floor space, was outstanding. It was very encouraging to see new instruments on display, including a FEG electron microprobe as a first worldwide presentation. Moreover, almost all the companies that exhibited provided financial support, either by sponsoring an event or by advertising. Below, in alphabetical order, is a list of exhibiting companies and sponsors of the workshop: Ametek GmbH, Edax Business UnitGN-MEBA Bruker Nano GmbHJeol (Europe) SAS CamecaL'Oréal, Direction Générale Recherche et Innovation Carl Zeiss NTSNanoMEGAS sprl Commissariat à l'Energie AtomiqueOxford Instruments SAS European Institute for Transuranium Elements (Germany)Probe Software, Inc. ElexienceSAMx FEI CompanyTarget-Messtechnik Fondis Electronic SAThermo Fisher Scientific Gatan (France) Clive T. Walker

  17. Multifrequency Excitation of a Clamped-Clamped Microbeam

    KAUST Repository

    Jaber, Nizar R.

    2016-01-20

    We present analytical and experimental investigation of an electrically actuated clamped-clamped microbeam under a twosource harmonic excitation. The first frequency is swept around the first mode of vibration where the second one is fixed. These microbeams are fabricated using polyimide as structural layer coated with nickel form top and chromium and gold layers from bottom. We demonstrate the excitation of additive and subtractive type resonance. We show that by properly tuning the frequency and the amplitude of the excitation force, the frequency bandwidth of the resonator is increased. Theoretically, we solved the eigenvalue problem for different axial forces to find the natural frequencies ratio that match the experimental values. Using Galerkin method, a reduced order model is derived to simulate the static and dynamic response of the device where using three symmetric mode shapes provided a good agreement with experimental data. © Copyright 2015 by ASME.

  18. In situ monitoring of polyimide windows for external ion microbeams

    International Nuclear Information System (INIS)

    Damage of polyimide windows for external ion microbeams was monitored by analyzing backscattering protons from the window. A 1.5 MeV proton microbeam focused to approximately 50 x 50 μm2 was transmitted through the polyimide window from vacuum to oxygen atmosphere. The changes in backscattering spectra of the window were monitored as a function of irradiation dose up to 2 x 1018 H+/cm2. For comparison, the polyimide window was irradiated in vacuum in the same way as the oxygen case. The backscattering spectra drastically changed in the case of oxygen. We observed that the carbon spectrum width, corresponding to the thickness of the window, substantially decreased with increasing the irradiation dose. The in situ monitoring of backscattering protons demonstrated the ability to detect the damage of the window and to predict the rupture of the window

  19. Automatic cell detection in bright-field microscopy for microbeam irradiation studies

    International Nuclear Information System (INIS)

    Automatic cell detection in bright-field illumination microscopy is challenging due to cells’ inherent optical properties. Applications including individual cell microbeam irradiation demand minimisation of additional cell stressing factors, so contrast-enhancing fluorescence microscopy should be avoided. Additionally, the use of optically non-homogeneous substrates amplifies the problem. This research focuses on the design of a method for automatic cell detection on polypropylene substrate, suitable for microbeam irradiation. In order to fulfil the relative requirements, the Harris corner detector was employed to detect apparent cellular features. These features-corners were clustered based on a dual-clustering technique according to the density of their distribution across the image. Weighted centroids were extracted from the clusters of corners and constituted the targets for irradiation. The proposed method identified more than 88% of the 1,738 V79 Chinese hamster cells examined. Moreover, a processing time of 2.6 s per image fulfilled the requirements for a near real-time cell detection-irradiation system. (paper)

  20. Automatic cell detection in bright-field microscopy for microbeam irradiation studies

    Science.gov (United States)

    Georgantzoglou, A.; Merchant, M. J.; Jeynes, J. C. G.; Wéra, A.-C.; Kirkby, K. J.; Kirkby, N. F.; Jena, R.

    2015-08-01

    Automatic cell detection in bright-field illumination microscopy is challenging due to cells’ inherent optical properties. Applications including individual cell microbeam irradiation demand minimisation of additional cell stressing factors, so contrast-enhancing fluorescence microscopy should be avoided. Additionally, the use of optically non-homogeneous substrates amplifies the problem. This research focuses on the design of a method for automatic cell detection on polypropylene substrate, suitable for microbeam irradiation. In order to fulfil the relative requirements, the Harris corner detector was employed to detect apparent cellular features. These features-corners were clustered based on a dual-clustering technique according to the density of their distribution across the image. Weighted centroids were extracted from the clusters of corners and constituted the targets for irradiation. The proposed method identified more than 88% of the 1,738 V79 Chinese hamster cells examined. Moreover, a processing time of 2.6 s per image fulfilled the requirements for a near real-time cell detection-irradiation system.

  1. On using the dynamic snap-through motion of MEMS initially curved microbeams for filtering applications

    KAUST Repository

    Ouakad, Hassen M.

    2014-01-01

    Numerical and experimental investigations of the dynamics of micromachined shallow arches (initially curved microbeams) and the possibility of using their dynamic snap-through motion for filtering purposes are presented. The considered MEMS arches are actuated by a DC electrostatic load along with an AC harmonic load. Their dynamics is examined numerically using a Galerkin-based reduced-order model when excited near both their first and third natural frequencies. Several simulation results are presented demonstrating interesting jumps and dynamic snap-through behavior of the MEMS arches and their attractive features for uses as band-pass filters, such as their sharp roll-off from pass-bands to stop-bands and their flat response. Experimental work is conducted to test arches realized of curved polysilicon microbeams when excited by DC and AC loads. Experimental data of the micromachined curved beams are shown for the softening and hardening behavior near the first and third natural frequencies, respectively, as well as dynamic snap-through motion. © 2013 Elsevier Ltd.

  2. Contribution of the surface contamination of uranium-materials on the quantitative analysis results by electron probe microbeam analysis; Contributions des effets de surface des materiaux uraniferes aux resultats d'analyses quantitatives par microsonde electronique a dispersion de longueur d'onde

    Energy Technology Data Exchange (ETDEWEB)

    Bonino, O.; Fournier, C.; Fucili, C.; Dugne, O. [CEA Valrho, (DCC/DTE/SIM), 30 - Marcoule (France); Merlet, C. [Montpellier-2 Univ. (ISTEEM/CNRS), 34 (France)

    2000-07-01

    The analytical testing of uranium materials is necessary for quality research and development in nuclear industry applications (enrichment, safety studies, fuel, etc). Electron Probe Microbeam Analysis Wavelength Dispersive Spectrometry (EPMA-WDS) is a dependable non-destructive analytical technology. The characteristic X-ray signal is measured to identify and quantify the sample components, and the analyzed volume is about one micron cube. The surface contamination of uranium materials modifies and contributes to the quantitative analysis results of EPMA-WDS. This contribution is not representative of the bulk. A thin oxidized layer appears in the first instants after preparation (burnishing, cleaning) as well as a carbon contamination layer, due to metallographic preparation and carbon cracking under the impact of the electron probe. Several analytical difficulties subsequently arise, including an overlapping line between the carbon Ka ray and the Uranium U{sub NIVOVI} ray. Sensitivity and accuracy of the quantification of light elements like carbon and oxygen are also reduced by the presence of uranium. The aim of this study was to improve the accuracy of quantitative analysis on uranium materials by EPMA-WDS by taking account of the contribution of surface contamination. The first part of this paper is devoted to the study of the contaminated surface of the uranium materials U, UFe{sub 2} and U{sub 6}Fe a few hours after preparation. These oxidation conditions are selected so as to reproduce the same contamination surfaces occurring in microprobe analytical conditions. Surface characterization techniques were SIMS and Auger spectroscopy. The contaminated surfaces are shown. They consist of successive layers: a carbon layer, an oxidized iron layer, followed by an iron depletion layer (only in UFe{sub 2} and U{sub 6}Fe), and a ternary oxide layer (U-Fe-O for UFe{sub 2} et U{sub 6}Fe and UO{sub 2+x} for uranium). The second part of the paper addresses the

  3. A table-top x-ray microbeam scanning facility

    Science.gov (United States)

    Attaelmanan, A.; Larsson, S.; Rindby, A.; Voglis, P.; Kuczumow, A.

    1994-01-01

    The x-ray microbeam scanning facility in our laboratory at Chalmers University of Technology/Göteborg University is described in terms of optical and mechanical design, imaging capacity, spatial resolution, and sensitivity. Different types of visualization of the elemental distribution are demonstrated and application of image processing is discussed. Examples of applications in the field of single-particle analysis as well as tree ring analysis are given. Future perspectives of the technique are also discussed.

  4. Extended abstracts: Microbeam Probes of Cellular Radiation Response [final report

    International Nuclear Information System (INIS)

    In July 1999, we organized the 4th International Workshop: Microbeam Probes of Cellular Radiation Response, held in Killiney Bay, Dublin, Ireland, on July 17-18. Roughly 75 scientists (about equal numbers of physicists and biologists) attended the workshop, the fourth in a bi-annual series. Extended abstracts from the meeting were published in the Radiation Research journal, vol. 153, iss. 2, pp. 220-238 (February 2000)(attached). All the objectives in the proposal were met

  5. Micro-beam XRF localization by a laser beam

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A new method for micro-beam XRF localization is presented. A laserbeam along with an incident X-ray hits on the surface of a sample. The micro region onthe sample that reached by X-ray beam can be localized by means of thevisible spot of the laser beam. This method is suitable for X-ray microprobesusing anX-ray tube or synchrotron radiation as excitation sources.

  6. Snap-through and pull-in analysis of an electro-dynamically actuated curved micro-beam using a nonlinear beam model

    Science.gov (United States)

    Hu, Y. J.; Yang, J.; Kitipornchai, S.

    2013-07-01

    This paper presents a geometrically nonlinear micro-beam model for the electro-dynamic analysis of an initially curved micro-beam under an applied voltage, with an emphasis on its snap-through and pull-in behaviors. The governing equations of motion and the associated boundary conditions are derived in an arc coordinate system without involving any assumptions on the nonlinear deformation. Differential quadrature method (DQM) and Petzold-Gear Backward Differentiation Formulas (BDF) are employed to solve the governing equations in the space and time domains respectively to obtain the nonlinear fundamental frequency, snap-through voltage, pull-in voltage and the corresponding mode shapes of a micro-beam clamped at both ends. The present analysis is validated through a direct comparison with the published experimental and numerical results. A parametric study is conducted to investigate the influences of the initial gap, base length, arc rise, and initial curved configuration on the snap-through and pull-in behaviors of the micro-beam.

  7. Ion microbeam analysis. Application to the study of the skin barrier and its nano-toxicology

    International Nuclear Information System (INIS)

    This work is dedicated to the use of ion microbeam irradiation to the study of a complex biological tissue like skin. Up to now, it has been very difficult to detect and track metallic oxides and manufactured nano-particles in biological tissues, most particularly in skin. Thus, it is essential to precise the mechanisms involved in skin barrier function processes face to exogenous agents like nano-particles and to characterize them in biological models in vitro/in vivo. During my work, I have had the opportunity to combine quantitative methods of analysis with high resolution imagery techniques (confocal microscopy, transmission electron microscopy and ion beam analysis) in order to characterize: (i) the skin barrier function of an ex vivo pig ear skin model understanding the ion homeostasis behavior face to different chemical or physical stresses; (ii) the impact on viability, accumulation and intracellular distribution of nano-particles (Titanium Oxides) naked or functionalized with fluorescent dyes (FITC, Rhodamine)

  8. Tip-based electron source for femtosecond electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Jan-Paul; Hoffrogge, Johannes; Schenk, Markus; Krueger, Michael; Baum, Peter; Hommelhoff, Peter [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching bei Muenchen (Germany)

    2012-07-01

    Illumination of a sharp tungsten tip with femtosecond laser pulses leads to the emission of ultrashort, high brightness electron pulses that are ideally suited for ultrafast electron diffraction (UED) experiments [1]. The tip's small virtual source size ({proportional_to}5 nm) results in a large transverse coherence length of the electron pulse and therefore better spatial resolution as compared to a conventional flat cathode design. The enhanced electric field at the tip apex (2 GV/m) is about two orders of magnitude larger than the maximum electric field applicable in a plate capacitor based setup (20 MV/m). This reduces the influence of the initial energy distribution on the pulse duration at the target and improves the timing jitter. Simulations show that a setup with a sharp tip as the cathode in combination with two anodes yields an electron pulse duration of about 50 fs at the sample. The electron energy is 30 keV and the gun to sample distance is 3 cm. We implemented the two anode setup with the tip experimentally. We present the experimental characteristics of the emitted electron beam both in static field emission and in laser triggered emission.

  9. Biomaterials-Based Organic Electronic Devices

    Science.gov (United States)

    Bettinger, Christopher J.; Bao, Zhenan

    2010-01-01

    Organic electronic devices have demonstrated tremendous versatility in a wide range of applications including consumer electronics, photovoltaics, and biotechnology. The traditional interface of organic electronics with biology, biotechnology, and medicine occurs in the general field of sensing biological phenomena. For example, the fabrication of hybrid electronic structures using both organic semiconductors and bioactive molecules has led to enhancements in sensitivity and specificity within biosensing platforms, which in turn has a potentially wide range of clinical applications. However, the interface of biomolecules and organic semiconductors has also recently explored the potential use of natural and synthetic biomaterials as structural components of electronic devices. The fabrication of electronically active systems using biomaterials-based components has the potential to realize a large set of unique devices including environmentally biodegradable systems and bioresorbable temporary medical devices. This article reviews recent advances in the implementation of biomaterials as structural components in organic electronic devices with a focus on potential applications in biotechnology and medicine. PMID:20607127

  10. Electronic Seal Stamping Based on Group Signature

    OpenAIRE

    Girija Srikanth

    2011-01-01

    This paper describes a new electronic official seal stamping based on Group Signature, USB Key. Bill/Contract in E-commerce must be seal stamped to gain tamper proof and non-repudiation. The seal stamping control is designed based on the certificate-based public key. This technique is more efficient for generating and verifying individual/group signatures in terms of computational efforts and communication costs. Web page electronic seal-stamping system is implemented which has been adopted b...

  11. Graphene-Based Flexible and Stretchable Electronics.

    Science.gov (United States)

    Jang, Houk; Park, Yong Ju; Chen, Xiang; Das, Tanmoy; Kim, Min-Seok; Ahn, Jong-Hyun

    2016-06-01

    Graphene provides outstanding properties that can be integrated into various flexible and stretchable electronic devices in a conventional, scalable fashion. The mechanical, electrical, and optical properties of graphene make it an attractive candidate for applications in electronics, energy-harvesting devices, sensors, and other systems. Recent research progress on graphene-based flexible and stretchable electronics is reviewed here. The production and fabrication methods used for target device applications are first briefly discussed. Then, the various types of flexible and stretchable electronic devices that are enabled by graphene are discussed, including logic devices, energy-harvesting devices, sensors, and bioinspired devices. The results represent important steps in the development of graphene-based electronics that could find applications in the area of flexible and stretchable electronics.

  12. Development of a Charged Particle Microbeam for Targeted and Single Particle Subcellular Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yanch, Jacquelyn C.

    2004-03-12

    The development of a charged particle microbeam for single particle, subcellular irradiations at the Massachusetts Institute of Technology Laboratory for Accelerator Beam Applications (MIT LABA) was initiated under this NEER aeard. The Microbeam apparatus makes use of a pre-existing electrostatic accelerator with a horizontal beam tube.

  13. Study of transient current induced by heavy-ion microbeams in Si and GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Hirao, Toshio; Nashiyama, Isamu; Kamiya, Tomihiro; Suda, Tamotu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    Heavy-ion microbeams were applied to the study of mechanism of single event upset (SEU). Transient current induced in p{sup +}n junction diodes by strike of heavy ion microbeam were measured by using a high-speed digitizing sampling system. (author)

  14. Comparison of modeling of the rotating tapered axially functionally graded Timoshenko and Euler-Bernoulli microbeams

    Science.gov (United States)

    Shafiei, Navvab; Kazemi, Mohammad; Ghadiri, Majid

    2016-09-01

    The target of this paper is to present an exhaustive study on the small scale effect on vibrational behavior of a rotary tapered axially functionally graded (AFG) microbeam on the basis of Timoshenko and Euler-Bernoulli beam and modified couple stress theories. The variation of the material properties and cross section along the longitudinal direction of the microbeam are taken into consideration as a linear function. Hamilton's principle is used to derive the equations for cantilever and propped cantilever boundary conditions and the generalized differential quadrature method (GDQM) is employed to solve the equations. By parametric study, the effects of small-scale parameter, rates of cross section change of the microbeam and angular velocity on the fundamental and second frequencies of the microbeam are studied. Also, comparison between the frequencies of Timoshenko and Euler-Bernoulli microbeams are presented. The results can be used in many applications such as micro-robots and biomedical microsystems.

  15. A study with microbeam PIXE technique needed for the interpretation of data on pollutants in hair obtained with NAA and other bulk concentration analysis. Part of a coordinated programme on nuclear-based methods for analysis of pollutants in human hair

    International Nuclear Information System (INIS)

    Hair metals the analysis of which has been proposed as a practical method for assaying human contamination with metal pollutants, reflect both internal and external contamination. This study is an attempt to distinguish these two components of hair metals, using the scanning microbeam PIXE technique. Individual hair strands were embedded in a resin combined with a hardener. Each embedded hair strand was cut perpendicular to its axis, into the root, 1-cm and 2-cm segments from the root. The 3 segments were analysed for few elements including As and Pb, using the scanning microbeam PIXE technique. For each segment, a proton microbeam of 15μ diameter and 500Hz frequency was used to scan the segment cross-section along the long axis. X-ray spectrometry was used to determine the concentrations of the elements studied. The results, although preliminary, showed that the scanning microbeam PIXE technique may provide important information about elemental concentrations and distribution patterns along hair length and hair cross-section. This may lead to a better understanding of mechanisms responsible for the deposition of elements into hair and thereby to a more rational use of hair analysis as a method for assaying human exposure to element pollutants

  16. Fair Electronic Payment Scheme Based on DSA

    Institute of Scientific and Technical Information of China (English)

    WANG Shao-bin; HONG Fan; ZHU Xian

    2005-01-01

    We present a multi-signature scheme based on DSA and describes a fair electronic payment scheme based on improved DSA signatures. The scheme makes both sides in equal positions during the course of electronic transaction. A Trusted Third Party (TTP) is involved in the scheme to guarantee the fairness of the scheme for both sides. However, only during the course of registration and dispute resolution will TTP be needed. TTP is not needed during the normal payment stage.

  17. Anonymous Fingerprinting Based on Electronic Cash

    Institute of Scientific and Technical Information of China (English)

    CHENXiaofeng; ZHANGFangguo; WANGJilin; WANGYumin

    2003-01-01

    A new anonymous fingerprinting protocol based on the principle of electronic cash is proposed in this paper.Redistributing a data item is equal to doublespending electronic cash.Contrasting with the previous coin-based anonymous fingerprinting protocol,we use the real electronic cash to trace traitors instead of the "coins" which serve only as a cryptographic primitive and have no monetary value,so it is easily understood and the bank does not need key-distribution and registration to prepare the "coina".

  18. Applications of high-throughput clonogenic survival assays in high-LET particle microbeams

    Directory of Open Access Journals (Sweden)

    Antonios eGeorgantzoglou

    2016-01-01

    Full Text Available Charged particle therapy is increasingly becoming a valuable tool in cancer treatment, mainly due to the favorable interaction of particle radiation with matter. Its application is still limited due, in part, to lack of data regarding the radiosensitivity of certain cell lines to this radiation type, especially to high-LET particles. From the earliest days of radiation biology, the clonogenic survival assay has been used to provide radiation response data. This method produces reliable data but it is not optimized for high-throughput microbeam studies with high-LET radiation where high levels of cell killing lead to a very low probability of maintaining cells’ clonogenic potential. A new method, therefore, is proposed in this paper, which could potentially allow these experiments to be conducted in a high-throughput fashion. Cells are seeded in special polypropylene dishes and bright-field illumination provides cell visualization. Digital images are obtained and cell detection is applied based on corner detection, generating individual cell targets as x-y points. These points in the dish are then irradiated individually by a micron field size high-LET microbeam. Post-irradiation, time-lapse imaging follows cells’ response. All irradiated cells are tracked by linking trajectories in all time-frames, based on finding their nearest position. Cell divisions are detected based on cell appearance and individual cell temporary corner density. The number of divisions anticipated is low due to the high probability of cell killing from high-LET irradiation. Survival curves are produced based on cell’s capacity to divide at least 4-5 times. The process is repeated for a range of doses of radiation. Validation shows the efficiency of the proposed cell detection and tracking method in finding cell divisions.

  19. MFM and PEEM observation of micrometre-sized magnetic dot arrays fabricated by ion-microbeam irradiation in FeRh thin films.

    Science.gov (United States)

    Aikoh, K; Tohki, A; Matsui, T; Iwase, A; Satoh, T; Takano, K; Kohka, M; Saitoh, Y; Kamiya, T; Ohkochi, T; Kotsugi, M; Nakamura, T; Kinoshita, T

    2012-03-01

    FeRh thin films were irradiated with a 10 MeV iodine ion microbeam to produce micrometre-scale ferromagnetic microstructures by modifying the local magnetic character from antiferromagnetism to ferromagnetism using ion-microbeam irradiation. Two-dimensional magnetic dot arrays of dimensions ∼2 µm × 4 µm as well as 10 µm × 10 µm were successfully produced on the FeRh surface, which was confirmed by magnetic force microscopy (MFM). The results of photoemission electron microscopy (PEEM) combined with X-ray magnetic circular dichroism reveal that the easy axis of the magnetization of the ion-beam-irradiated ferromagnetism in the FeRh thin films lies in the film planes along the direction of the MgO substrates. PMID:22338683

  20. Single-ion microbeam as a tool for low-dose radiation effects investigations

    Energy Technology Data Exchange (ETDEWEB)

    Gerardi, Silvia [INFN - Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy); Galeazzi, Giuseppe [INFN - Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy); Cherubini, Roberto [INFN - Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy)

    2006-05-15

    Practical assessment of human radiation exposure risk deserves particular attention especially for low doses (and low dose rates), which concern environmental and occupational exposure. At these dose levels ionizing radiation exposures involve mainly isolated charged particle tracks, which strike individual cells at time intervals averaging from weeks to several years apart. Accelerator-based microbeam irradiation technique offers a unique tool to mimic such an exposure, allowing irradiating single cells individually with micrometer precision and with a preset number of charged particles down to one particle per cell. A horizontal single-ion microbeam facility for single-cell irradiations has been designed and set up at the INFN-LNL 7MV CN Van de Graaff accelerator. The light ion beam is collimated in air down to a section of 2-3{mu}m in diameter by means of appropriate pinholes. Semi-automatic cell visualization and automatic cell positioning and revisiting system, based on an inverted phase contrast optical microscope and on X-Y translation stages with 0.1{mu}m positioning precision, has been developed. An in-house-written software allows to control remotely the irradiation protocol. As a distinctive feature of the facility, cell recognition is performed without using fluorescent staining and UV light. Particle detection in air, behind the biological sample, is based on a silicon detector while in-air beam profile and precise hit position measurements are accomplished by a custom-made cooled-CCD camera and Solid State Nuclear Track detectors, respectively. A particle counting rate of less than 1 ion/sec can be reached.

  1. Single-ion microbeam as a tool for low-dose radiation effects investigations

    Science.gov (United States)

    Gerardi, Silvia; Galeazzi, Giuseppe; Cherubini, Roberto

    2006-05-01

    Practical assessment of human radiation exposure risk deserves particular attention especially for low doses (and low dose rates), which concern environmental and occupational exposure. At these dose levels ionizing radiation exposures involve mainly isolated charged particle tracks, which strike individual cells at time intervals averaging from weeks to several years apart. Accelerator-based microbeam irradiation technique offers a unique tool to mimic such an exposure, allowing irradiating single cells individually with micrometer precision and with a preset number of charged particles down to one particle per cell. A horizontal single-ion microbeam facility for single-cell irradiations has been designed and set up at the INFN-LNL 7MV CN Van de Graaff accelerator. The light ion beam is collimated in air down to a section of 2-3µm in diameter by means of appropriate pinholes. Semi-automatic cell visualization and automatic cell positioning and revisiting system, based on an inverted phase contrast optical microscope and on X-Y translation stages with 0.1µm positioning precision, has been developed. An in-house-written software allows to control remotely the irradiation protocol. As a distinctive feature of the facility, cell recognition is performed without using fluorescent staining and UV light. Particle detection in air, behind the biological sample, is based on a silicon detector while in-air beam profile and precise hit position measurements are accomplished by a custom-made cooled-CCD camera and Solid State Nuclear Track detectors, respectively. A particle counting rate of less than 1 ion/sec can be reached.

  2. Graphitized silicon carbide microbeams: wafer-level, self-aligned graphene on silicon wafers

    Science.gov (United States)

    Cunning, Benjamin V.; Ahmed, Mohsin; Mishra, Neeraj; Ranjbar Kermany, Atieh; Wood, Barry; Iacopi, Francesca

    2014-08-01

    Currently proven methods that are used to obtain devices with high-quality graphene on silicon wafers involve the transfer of graphene flakes from a growth substrate, resulting in fundamental limitations for large-scale device fabrication. Moreover, the complex three-dimensional structures of interest for microelectromechanical and nanoelectromechanical systems are hardly compatible with such transfer processes. Here, we introduce a methodology for obtaining thousands of microbeams, made of graphitized silicon carbide on silicon, through a site-selective and wafer-scale approach. A Ni-Cu alloy catalyst mediates a self-aligned graphitization on prepatterned SiC microstructures at a temperature that is compatible with silicon technologies. The graphene nanocoating leads to a dramatically enhanced electrical conductivity, which elevates this approach to an ideal method for the replacement of conductive metal films in silicon carbide-based MEMS and NEMS devices.

  3. Graphitized silicon carbide microbeams: wafer-level, self-aligned graphene on silicon wafers

    International Nuclear Information System (INIS)

    Currently proven methods that are used to obtain devices with high-quality graphene on silicon wafers involve the transfer of graphene flakes from a growth substrate, resulting in fundamental limitations for large-scale device fabrication. Moreover, the complex three-dimensional structures of interest for microelectromechanical and nanoelectromechanical systems are hardly compatible with such transfer processes. Here, we introduce a methodology for obtaining thousands of microbeams, made of graphitized silicon carbide on silicon, through a site-selective and wafer-scale approach. A Ni-Cu alloy catalyst mediates a self-aligned graphitization on prepatterned SiC microstructures at a temperature that is compatible with silicon technologies. The graphene nanocoating leads to a dramatically enhanced electrical conductivity, which elevates this approach to an ideal method for the replacement of conductive metal films in silicon carbide-based MEMS and NEMS devices. (paper)

  4. Fabrication of nanowires by varying energy microbeam lithography using heavy ions at the TIARA

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, T. [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)], E-mail: kamiya.tomihiro@jaea.go.jp; Takano, K.; Ishii, Y.; Satoh, T.; Oikawa, M.; Ohkubo, T.; Haga, J. [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Nishikawa, H.; Furuta, Y.; Uchiya, N. [Dept. of Electrical Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Seki, S. [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Sugimoto, M. [Quatum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

    2009-06-15

    In TIARA facility of Japan Atomic Energy Agency (JAEA) Takasaki, we have produced three-dimensional micro/nano-structures with high aspect ratio using cross linking process based on negative resist such as SU-8 by a technique of mask less ion beam lithography. By bombarding high energy heavy ions such as 450 MeV Xe{sup 23+} to SU-8, on the other hand, it appeared that a nanowire could be produced just with a single ion hitting. Then we tried to produce nanowires, of which both ends were fixed in the three-dimensional structure. This paper shows a preliminary experiment for this purpose using a combination of 15 MeV Ni{sup 4+} ion microbeam patterning and the 450 MeV {sup 129}Xe{sup 23+} hitting on SU-8.

  5. Electronic structure of Fe-based superconductors

    Indian Academy of Sciences (India)

    Kalobaran Maiti

    2015-06-01

    Fe-based superconductors have drawn much attention during the last decade due to the presence of superconductivity in materials containing the magnetic element, Fe, and the coexistence of superconductivity and magnetism. Extensive study of the electronic structure of these systems suggested the dominant role of states in their electronic properties, which is significantly different from the cuprate superconductors. In this article, some of our studies of the electronic structure of these fascinating systems employing high-resolution photoemission spectroscopy is reviewed. The combined effect of electron correlation and covalency reveals an interesting scenario in their electronic structure. The contribution of ligand states at the Fermi level is found to be much more significant than indicated in earlier studies. Temperature evolution of the energy bands reveals the signature of transition akin to Lifshitz transition in these systems.

  6. Electronic Seal Stamping Based on Group Signature

    Directory of Open Access Journals (Sweden)

    Girija Srikanth

    2011-05-01

    Full Text Available This paper describes a new electronic official seal stamping based on Group Signature, USB Key. Bill/Contract in E-commerce must be seal stamped to gain tamper proof and non-repudiation. The seal stamping control is designed based on the certificate-based public key. This technique is more efficient for generating and verifying individual/group signatures in terms of computational efforts and communication costs. Web page electronic seal-stamping system is implemented which has been adopted by CNBAB platform since Mar., 2008

  7. TSET: Token based Secure Electronic Transaction

    OpenAIRE

    Borgohain, Rajdeep; Singh, Moirangthem Tiken; Sakharwade, Chandrakant; Sanyal, Sugata

    2012-01-01

    Security and trust are the most important factors in online transaction, this paper introduces TSET a Token based Secure Electronic Transaction which is an improvement over the existing SET, Secure Electronic Transaction protocol. We take the concept of tokens in the TSET protocol to provide end to end security. It also provides trust evaluation mechanism so that trustworthiness of the merchants can be known by customers before being involved in the transaction. Moreover, we also propose a gr...

  8. An Experimental and Theoretical Investigation of Electrostatically Coupled Cantilever Microbeams

    KAUST Repository

    Ilyas, Saad

    2016-06-16

    We present an experimental and theoretical investigation of the static and dynamic behavior of electrostatically coupled laterally actuated silicon microbeams. The coupled beam resonators are composed of two almost identical flexible cantilever beams forming the two sides of a capacitor. The experimental and theoretical analysis of the coupled system is carried out and compared against the results of beams actuated with fixed electrodes individually. The pull-in characteristics of the electrostatically coupled beams are studied, including the pull-in time. The dynamics of the coupled dual beams are explored via frequency sweeps around the neighborhood of the natural frequencies of the system for different input voltages. Good agreement is reported among the simulation results and the experimental data. The results show considerable drop in the pull-in values as compared to single microbeam resonators. The dynamics of the coupled beam resonators are demonstrated as a way to increase the bandwidth of the resonator near primary resonance as well as a way to introduce increased frequency shift, which can be promising for resonant sensing applications. Moreover the dynamic pull-in characteristics are also studied and proposed as a way to sense the shift in resonance frequency.

  9. MOF-based electronic and opto-electronic devices.

    Science.gov (United States)

    Stavila, V; Talin, A A; Allendorf, M D

    2014-08-21

    Metal-organic frameworks (MOFs) are a class of hybrid materials with unique optical and electronic properties arising from rational self-assembly of the organic linkers and metal ions/clusters, yielding myriads of possible structural motifs. The combination of order and chemical tunability, coupled with good environmental stability of MOFs, are prompting many research groups to explore the possibility of incorporating these materials as active components in devices such as solar cells, photodetectors, radiation detectors, and chemical sensors. Although this field is only in its incipiency, many new fundamental insights relevant to integrating MOFs with such devices have already been gained. In this review, we focus our attention on the basic requirements and structural elements needed to fabricate MOF-based devices and summarize the current state of MOF research in the area of electronic, opto-electronic and sensor devices. We summarize various approaches to designing active MOFs, creation of hybrid material systems combining MOFs with other materials, and assembly and integration of MOFs with device hardware. Critical directions of future research are identified, with emphasis on achieving the desired MOF functionality in a device and establishing the structure-property relationships to identify and rationalize the factors that impact device performance. PMID:24802763

  10. 7th International Workshop on Microbeam Probes of Cellular Radiation Response

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, David J.

    2009-07-21

    The extended abstracts that follow present a summary of the Proceedings of the 7th International Workshop: Microbeam Probes of Cellular Radiation Response, held at Columbia University’s Kellogg Center in New York City on March 15–17, 2006. These International Workshops on Microbeam Probes of Cellular Radiation Response have been held regularly since 1993 (1–5). Since the first workshop, there has been a rapid growth (see Fig. 1) in the number of centers developing microbeams for radiobiological research, and worldwide there are currently about 30 microbeams in operation or under development. Single-cell/single-particle microbeam systems can deliver beams of different ionizing radiations with a spatial resolution of a few micrometers down to a few tenths of a micrometer. Microbeams can be used to addressquestions relating to the effects of low doses of radiation (a single radiation track traversing a cell or group of cells), to probe subcellular targets (e.g. nucleus or cytoplasm), and to address questions regarding the propagation of information about DNA damage (for example, the radiation-induced bystander effect). Much of the recent research using microbeams has been to study low-dose effects and ‘‘non-targeted’’ responses such as bystander effects, genomic instability and adaptive responses. This Workshop provided a forum to assess the current state of microbeam technology and current biological applications and to discuss future directions for development, both technological and biological. Over 100 participants reviewed the current state of microbeam research worldwide and reported on new technological developments in the fields of both physics and biology.

  11. Structure of kinetochore fibres in crane-fly spermatocytes after irradiation with an ultraviolet microbeam: neither microtubules nor actin filaments remain in the irradiated region.

    Science.gov (United States)

    Forer, Arthur; Spurck, Tim; Pickett-Heaps, Jeremy D; Wilson, Paula J

    2003-11-01

    We studied chromosome movement after kinetochore microtubules were severed. Severing a kinetochore fibre in living crane-fly spermatocytes with an ultraviolet microbeam creates a kinetochore stub, a birefringent remnant of the spindle fibre connected to the kinetochore and extending only to the edge of the irradiated region. After the irradiation, anaphase chromosomes either move poleward led by their stubs or temporarily stop moving. We examined actin and/or microtubules in irradiated cells by means of confocal fluorescence microscopy or serial-section reconstructions from electron microscopy. For each cell thus examined, chromosome movement had been recorded continuously until the moment of fixation. Kinetochore microtubules were completely severed by the ultraviolet microbeam in cells in which chromosomes continued to move poleward after the irradiation: none were seen in the irradiated regions. Similarly, actin filaments normally present in kinetochore fibres were severed by the ultraviolet microbeam irradiations: the irradiated regions contained no actin filaments and only local spots of non-filamentous actin. There was no difference in irradiated regions when the associated chromosomes continued to move versus when they stopped moving. Thus, one cannot explain motion with severed kinetochore microtubules in terms of either microtubules or actin-filaments bridging the irradiated region. The data seem to negate current models for anaphase chromosome movement and support a model in which poleward chromosome movement results from forces generated within the spindle matrix that propel kinetochore fibres or kinetochore stubs poleward. PMID:14569597

  12. Microbeam synchrotron radiation diffraction and fluorescence study of oxide layers formed on 9Cr ODS steel in supercritical water

    International Nuclear Information System (INIS)

    Uniform corrosion is a major concern for ferritic-martensitic steels when considered as candidate materials for the supercritical water reactor (SCWR). The corrosion rate depends on alloy composition and microstructure. The best ferritic-martensitic alloys resist corrosion by developing a protective oxide layer that stabilizes oxide growth. To better understand the protection and stabilization mechanism, the structure of oxide layers formed on ferritic-martensitic alloys in supercritical water is studied using both transmission electron microscopy and microbeam synchrotron radiation diffraction and fluorescence. Using the microbeam it is possible to determine phases present using x-ray diffraction and chemical composition using x-ray fluorescence, both as a function of location in the oxide layer. The detailed study of phases present and elemental segregation at interfaces is presented for an oxide formed on 9Cr ODS steel after exposure to supercritical water for 667 hours. In the diffusion layer, both metal and oxide peaks are seen indicating a coexistence of the two phases in the diffusion layer. In the Cr-rich inner layer, a mixture of spinel phase FeCr2O4 and Fe3O4 is observed, while in the outer oxide layer, Fe3O4 is the predominant phase. Evidence for additional Cr-rich phases near the interfaces is also shown. (author)

  13. Low Noise Electronics for BASE Collaboration

    CERN Document Server

    Besirli, Mustafa

    2015-01-01

    In my summer student period, I worked within the BASE (Baryon Antibaryon Symmetry Experiment) Collaboration and I developed low noise electronics such as cryogenic low noise amplifier and high voltage filters. In this report, you can find designs and measurements of my projects.

  14. Single electron tunneling based arithmetic computation

    NARCIS (Netherlands)

    Lageweg, C.R.

    2004-01-01

    In this dissertation we investigate the implementation of computer arithmetic operations with Single Electron Tunneling (SET) technology based circuits. In our research we focus on the effective utilization of the SET technologys specific characteristic, i.e., the ability to control the transport of

  15. Metamaterial perfect absorber based hot electron photodetection.

    Science.gov (United States)

    Li, Wei; Valentine, Jason

    2014-06-11

    While the nonradiative decay of surface plasmons was once thought to be only a parasitic process that limits the performance of plasmonic devices, it has recently been shown that it can be harnessed in the form of hot electrons for use in photocatalysis, photovoltaics, and photodetectors. Unfortunately, the quantum efficiency of hot electron devices remains low due to poor electron injection and in some cases low optical absorption. Here, we demonstrate how metamaterial perfect absorbers can be used to achieve near-unity optical absorption using ultrathin plasmonic nanostructures with thicknesses of 15 nm, smaller than the hot electron diffusion length. By integrating the metamaterial with a silicon substrate, we experimentally demonstrate a broadband and omnidirectional hot electron photodetector with a photoresponsivity that is among the highest yet reported. We also show how the spectral bandwidth and polarization-sensitivity can be manipulated through engineering the geometry of the metamaterial unit cell. These perfect absorber photodetectors could open a pathway for enhancing hot electron based photovoltaic, sensing, and photocatalysis systems. PMID:24837991

  16. TSET: Token based Secure Electronic Transaction

    CERN Document Server

    Borgohain, Rajdeep; Sakharwade, Chandrakant; Sanyal, Sugata

    2012-01-01

    Security and trust are the most important factors in online transaction, this paper introduces TSET a Token based Secure Electronic Transaction which is an improvement over the existing SET, Secure Electronic Transaction protocol. We take the concept of tokens in the TSET protocol to provide end to end security. It also provides trust evaluation mechanism so that trustworthiness of the merchants can be known by customers before being involved in the transaction. Moreover, we also propose a grading mechanism so that quality of service in the transactions improves.

  17. Data base systems in electronic design engineering

    Science.gov (United States)

    Williams, D.

    1980-01-01

    The concepts of an integrated design data base system (DBMS) as it might apply to an electronic design company are discussed. Data elements of documentation, project specifications, project tracking, firmware, software, electronic and mechanical design can be integrated and managed through a single DBMS. Combining the attributes of a DBMS data handler with specialized systems and functional data can provide users with maximum flexibility, reduced redundancy, and increased overall systems performance. Although some system overhead is lost due to redundancy in transitory data, it is believed the combination of the two data types is advisable rather than trying to do all data handling through a single DBMS.

  18. Communication: Electron ionization of DNA bases

    Science.gov (United States)

    Rahman, M. A.; Krishnakumar, E.

    2016-04-01

    No reliable experimental data exist for the partial and total electron ionization cross sections for DNA bases, which are very crucial for modeling radiation damage in genetic material of living cell. We have measured a complete set of absolute partial electron ionization cross sections up to 500 eV for DNA bases for the first time by using the relative flow technique. These partial cross sections are summed to obtain total ion cross sections for all the four bases and are compared with the existing theoretical calculations and the only set of measured absolute cross sections. Our measurements clearly resolve the existing discrepancy between the theoretical and experimental results, thereby providing for the first time reliable numbers for partial and total ion cross sections for these molecules. The results on fragmentation analysis of adenine supports the theory of its formation in space.

  19. Communication: Electron ionization of DNA bases.

    Science.gov (United States)

    Rahman, M A; Krishnakumar, E

    2016-04-28

    No reliable experimental data exist for the partial and total electron ionization cross sections for DNA bases, which are very crucial for modeling radiation damage in genetic material of living cell. We have measured a complete set of absolute partial electron ionization cross sections up to 500 eV for DNA bases for the first time by using the relative flow technique. These partial cross sections are summed to obtain total ion cross sections for all the four bases and are compared with the existing theoretical calculations and the only set of measured absolute cross sections. Our measurements clearly resolve the existing discrepancy between the theoretical and experimental results, thereby providing for the first time reliable numbers for partial and total ion cross sections for these molecules. The results on fragmentation analysis of adenine supports the theory of its formation in space. PMID:27131520

  20. Synchrotron microbeam irradiation induces neutrophil infiltration, thrombocyte attachment and selective vascular damage in vivo.

    Science.gov (United States)

    Brönnimann, Daniel; Bouchet, Audrey; Schneider, Christoph; Potez, Marine; Serduc, Raphaël; Bräuer-Krisch, Elke; Graber, Werner; von Gunten, Stephan; Laissue, Jean Albert; Djonov, Valentin

    2016-01-01

    Our goal was the visualizing the vascular damage and acute inflammatory response to micro- and minibeam irradiation in vivo. Microbeam (MRT) and minibeam radiation therapies (MBRT) are tumor treatment approaches of potential clinical relevance, both consisting of parallel X-ray beams and allowing the delivery of thousands of Grays within tumors. We compared the effects of microbeams (25-100 μm wide) and minibeams (200-800 μm wide) on vasculature, inflammation and surrounding tissue changes during zebrafish caudal fin regeneration in vivo. Microbeam irradiation triggered an acute inflammatory response restricted to the regenerating tissue. Six hours post irradiation (6 hpi), it was infiltrated by neutrophils and fli1a(+) thrombocytes adhered to the cell wall locally in the beam path. The mature tissue was not affected by microbeam irradiation. In contrast, minibeam irradiation efficiently damaged the immature tissue at 6 hpi and damaged both the mature and immature tissue at 48 hpi. We demonstrate that vascular damage, inflammatory processes and cellular toxicity depend on the beam width and the stage of tissue maturation. Minibeam irradiation did not differentiate between mature and immature tissue. In contrast, all irradiation-induced effects of the microbeams were restricted to the rapidly growing immature tissue, indicating that microbeam irradiation could be a promising tumor treatment tool. PMID:27640676

  1. The Progress of a Microbeam Facility in the Institute of Plasma Physics

    Institute of Scientific and Technical Information of China (English)

    吴瑜; 胡素华; 李军; 陈斌; 张束清; 王旭飞; 时钟涛; 袁航; 张俊; 王绍虎; 余增亮

    2003-01-01

    The progress of a microbeam facility in the Institute of Plasma Physics was discussed in this paper. This kind of equipment can supply single-particle beam which may be implanted into cells in micrometer-radius and measured by a new outstanding detector among global microbeam systems. Measurements by some plain targets showed that the highest current after the accelerator tube can be larger than 20μA, the H2+ current before the second bending magnet is near 0.9μA, the current after the second bending magnet is near 0.8μA, and the current of the beam line (after a 2-mm diameter aperture) is near 0.25 nA which is enough for the single-particle microbeam experiment. It took scientists 3 months to do their microbeam experiment after setting up the accelerator beam line and get the microbeam from this equipment. Two pre-collimators were installed between the 2-mm diameter aperture and the collimator to survey the beam. Tracks on the CR39 film etched in the solution of NaOH showed that the beam can go through the collimator including a 10μm diameter aperture and the 3.5μm thick vacuum sealing film (Mylar). A new method, which is called optimization of the beam quality, was put forward in this paper, in order to get smaller diameter of beam-spot in microbeam system.

  2. An FPGA-Based Electronic Cochlea

    Directory of Open Access Journals (Sweden)

    M. P. Leong

    2003-06-01

    Full Text Available A module generator which can produce an FPGA-based implementation of an electronic cochlea filter with arbitrary precision is presented. Although hardware implementations of electronic cochlea models have traditionally used analog VLSI as the implementation medium due to their small area, high speed, and low power consumption, FPGA-based implementations offer shorter design times, improved dynamic range, higher accuracy, and a simpler computer interface. The tool presented takes filter coefficients as input and produces a synthesizable VHDL description of an application-optimized design as output. Furthermore, the tool can use simulation test vectors in order to determine the appropriate scaling of the fixed point precision parameters for each filter. The resulting model can be used as an accelerator for research in audition or as the front-end for embedded auditory signal processing systems. The application of this module generator to a real-time cochleagram display is also presented.

  3. Graphene-based Electronically Tuneable Microstrip Attenuator

    Directory of Open Access Journals (Sweden)

    L. Pierantoni

    2014-06-01

    Full Text Available This paper presents the design of a graphene- based electronically tuneable microstrip attenuator operating at a frequency of 5 GHz. The use of graphene as a variable resistor is discussed and the modelling of its electromagnetic properties at microwave frequencies is fully addressed. The design of the graphene-based attenuator is described. The structure integrates a patch of graphene, whose characteristics can range from being a fairly good conductor to a highly lossy material, depending on the applied voltage. By applying the proper voltage through two high-impedance bias lines, the surface resistivity of graphene can be modified, thereby changing the insertion loss of the microstrip attenuator.

  4. Explanation-based knowledge acquisition of electronics

    Science.gov (United States)

    Kieras, David E.

    1992-08-01

    This is the final report in a project that examined how knowledge of practical electronics could be acquired from materials similar to that appearing in electronics training textbooks, from both an artificial intelligence perspective and an experimental psychology perspective. Practical electronics training materials present a series of basic circuits accompanied by an explanation of how the circuit performs the desired function. More complex circuits are then explained in terms of these basic circuits. This material thus presents schema knowledge for individual circuit types in the form of explanations of circuit behavior. Learning from such material would thus consist of first instantiating any applicable schemas, and then constructing a new schema based on the circuit structure and behavior described in the explanation. If the basic structure of the material is an effective approach to learning, learning about a new circuit should be easier if the relevant schemas are available than not. This result was obtained for both an artificial intelligence system that used standard explanation-based learning mechanisms and with human learners in a laboratory setting, but the benefits of already having the relevant schemas were not large in these materials. The close examination of learning in this domain, and the structure of knowledge, should be useful to future cognitive analyses of training in technical domains.

  5. Direct microfabrication using an x-ray micro-beam with a single refractive lens

    International Nuclear Information System (INIS)

    A micro-beam of hard X-ray (10 keV) as small as 5 μm in diameter has been generated using a single refractive lens made of polymers (e.g. PMMA, PTFE) and been applied for direct writing, which may find possible applications in three-dimensional (3D) micro-fabrication. The refractive lenses are parabolic-shaped concave lenses with a radius of 4 μm and an aperture of 179 μm and have been produced using our high aspect-ratio techniques with synchrotron radiation (SR) of our home-made compact storage ring, AURORA-2S (electron energy of 0.7 GeV). The lenses have two parabolic curvatures (R=4 μm) with apertures A=2(2Rz)1/2=179 μm, thus the aspect-ratio z/R=250 for its curvatures, which is too great for traditional techniques to achieve. The transmissions of our lenses were measured to be 54-85%, which is higher than that of a zone plate and a compound refractive lens. (author)

  6. Special Technologies Related to Electron Beam Welding

    Institute of Scientific and Technical Information of China (English)

    Zhao; Haiyan; Cai; Zhipeng; Wang; Xichang

    2007-01-01

    In order to improve the manufacturing quality of electron beam welding,some technologies are developed by using the special features of electron beam.Comparing with the conventional electron beam welding,the usage of multi-beam technology and micro-beam technology are introduced.In addition.the development of beam diagnostic system is also presented.

  7. Electron-avalanche amplifier based on the electronic Venturi effect

    Science.gov (United States)

    Taubert, D.; Schinner, G. J.; Tranitz, H. P.; Wegscheider, W.; Tomaras, C.; Kehrein, S.; Ludwig, S.

    2010-10-01

    Scattering of otherwise ballistic electrons far from equilibrium is investigated in a cold two-dimensional electron system. The interaction between excited electrons and the degenerate Fermi liquid induces a positive charge in a nanoscale region which would be negatively charged for diffusive transport at local thermal equilibrium. In a three-terminal device we observe avalanche amplification of electrical current, resulting in a situation comparable to the Venturi effect in hydrodynamics. Numerical calculations using a random-phase approximation are in agreement with our data and suggest Coulomb interaction as the dominant scattering mechanism.

  8. MOSFET dosimetry with high spatial resolution in intense synchrotron-generated x-ray microbeams.

    Science.gov (United States)

    Siegbahn, E A; Bräuer-Krisch, E; Bravin, A; Nettelbeck, H; Lerch, M L F; Rosenfeld, A B

    2009-04-01

    Various dosimeters have been tested for assessing absorbed doses with microscopic spatial resolution in targets irradiated by high-flux, synchrotron-generated, low-energy (approximately 30-300 keV) x-ray microbeams. A MOSFET detector has been used for this study since its radio sensitive element, which is extraordinarily narrow (approximately 1 microm), suits the main applications of interest, microbeam radiation biology and microbeam radiation therapy (MRT). In MRT, micrometer-wide, centimeter-high, and vertically oriented swaths of tissue are irradiated by arrays of rectangular x-ray microbeams produced by a multislit collimator (MSC). We used MOSFETs to measure the dose distribution, produced by arrays of x-ray microbeams shaped by two different MSCs, in a tissue-equivalent phantom. Doses were measured near the center of the arrays and maximum/minimum (peak/valley) dose ratios (PVDRs) were calculated to determine how variations in heights and in widths of the microbeams influenced this for the therapy, potentially important parameter. Monte Carlo (MC) simulations of the absorbed dose distribution in the phantom were also performed. The results show that when the heights of the irradiated swaths were below those applicable to clinical therapy (< 1 mm) the MC simulations produce estimates of PVDRs that are up to a factor of 3 higher than the measured values. For arrays of higher microbeams (i.e., 25 microm x 1 cm instead of 25 x 500 microm2), this difference between measured and simulated PVDRs becomes less than 50%. Closer agreement was observed between the measured and simulated PVDRs for the Tecomet MSC (current collimator design) than for the Archer MSC. Sources of discrepancies between measured and simulated doses are discussed, of which the energy dependent response of the MOSFET was shown to be among the most important. PMID:19472618

  9. MOSFET dosimetry with high spatial resolution in intense synchrotron-generated x-ray microbeams

    Energy Technology Data Exchange (ETDEWEB)

    Siegbahn, E. A.; Braeuer-Krisch, E.; Bravin, A.; Nettelbeck, H.; Lerch, M. L. F.; Rosenfeld, A. B. [European Synchrotron Radiation Facility (ESRF), 6 Rue Jules Horowitz, 38043 Grenoble (France); Center for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales 2522 (Australia)

    2009-04-15

    Various dosimeters have been tested for assessing absorbed doses with microscopic spatial resolution in targets irradiated by high-flux, synchrotron-generated, low-energy ({approx}30-300 keV) x-ray microbeams. A MOSFET detector has been used for this study since its radio sensitive element, which is extraordinarily narrow ({approx}1 {mu}m), suits the main applications of interest, microbeam radiation biology and microbeam radiation therapy (MRT). In MRT, micrometer-wide, centimeter-high, and vertically oriented swaths of tissue are irradiated by arrays of rectangular x-ray microbeams produced by a multislit collimator (MSC). We used MOSFETs to measure the dose distribution, produced by arrays of x-ray microbeams shaped by two different MSCs, in a tissue-equivalent phantom. Doses were measured near the center of the arrays and maximum/minimum (peak/valley) dose ratios (PVDRs) were calculated to determine how variations in heights and in widths of the microbeams influenced this for the therapy, potentially important parameter. Monte Carlo (MC) simulations of the absorbed dose distribution in the phantom were also performed. The results show that when the heights of the irradiated swaths were below those applicable to clinical therapy (<1 mm) the MC simulations produce estimates of PVDRs that are up to a factor of 3 higher than the measured values. For arrays of higher microbeams (i.e., 25 {mu}mx1 cm instead of 25x500 {mu}m{sup 2}), this difference between measured and simulated PVDRs becomes less than 50%. Closer agreement was observed between the measured and simulated PVDRs for the Tecomet MSC (current collimator design) than for the Archer MSC. Sources of discrepancies between measured and simulated doses are discussed, of which the energy dependent response of the MOSFET was shown to be among the most important.

  10. Characterization of high energy Xe ion irradiation effects in single crystal molybdenum with depth-resolved synchrotron microbeam diffraction

    Science.gov (United States)

    Yun, Di; Miao, Yinbin; Xu, Ruqing; Mei, Zhigang; Mo, Kun; Mohamed, Walid; Ye, Bei; Pellin, Michael J.; Yacout, Abdellatif M.

    2016-04-01

    Microbeam X-ray diffraction experiments were conducted at beam line 34-ID of the Advanced Photon Source (APS) on fission fragment energy Xe heavy ion irradiated single crystal Molybdenum (Mo). Lattice strain measurements were obtained with a depth resolution of 0.7 μm, which is critical in resolving the peculiar heterogeneity of irradiation damage associated with heavy ion irradiation. Q-space diffraction peak shift measurements were correlated with lattice strain induced by the ion irradiations. Transmission electron microscopy (TEM) characterizations were performed on the as-irradiated materials as well. Nanometer sized Xe bubble microstructures were observed via TEM. Molecular Dynamics (MD) simulations were performed to help interpret the lattice strain measurement results from the experiment. This study showed that the irradiation effects by fission fragment energy Xe ion irradiations can be collaboratively understood with the depth resolved X-ray diffraction and TEM measurements under the assistance of MD simulations.

  11. Multiparametric electronic devices based on nuclear tracks

    Energy Technology Data Exchange (ETDEWEB)

    Fink, D. [HMI Berlin, Glienicker Str. 100, 14109 Berlin (Germany)], E-mail: FINK@HMI.DE; Saad, A. [HMI Berlin, Glienicker Str. 100, 14109 Berlin (Germany); Basic Science Department, Faculty of Science, Al Balqa University, Salt (Jordan); Dhamodaran, S. [HMI Berlin, Glienicker Str. 100, 14109 Berlin (Germany); School of Physics, University of Hyderabad, Hyderabad 500 046 (India); Chandra, A. [HMI Berlin, Glienicker Str. 100, 14109 Berlin (Germany); Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India); Fahrner, W.R. [Chair of Electronic Devices, Institute of Electrotechnique, Fernuniversitaet, Hagen (Germany); Hoppe, K. [South Westfalia University of Applied Sciences, Hagen (Germany); Chadderton, L.T. [Institute of Advanced Studies, ANU Canberra, GPO Box 4, ACT (Australia)

    2008-08-15

    An overview is given on a family of novel electronic devices consisting of an insulating layer containing conducting or semiconducting nuclear tracks, deposited on a semiconducting substrate, and connected by at least one back and two surface contacts. Conducting and semiconducting latent tracks may emerge directly from swift heavy ion irradiation. Etched tracks in insulators can be filled with adequate materials to make them conducting or semiconducting. For this purpose metallic or semiconducting nanoclusters were deposited. We have denoted termed these devices made with latent tracks as 'tunable electronic anisotropic material on semiconductor' (TEAMS), if based on latent ion tracks, and as 'tunable electronic material in pores in oxide on semiconductor' (TEMPOS), if based on etched tracks. Depending on the band-to-band transition between tracks and substrate and on the ratio of surface to track conductivity, the current/voltage characteristics of TEAMS and TEMPOS structures can be modified in many different ways leading to tunable resistors, capacitors and diodes. Both devices show negative differential resistances. This should enable tunable tunneldiodes. TEAMS or TEMPOS structures can be controlled by various external physical and/or chemical parameters leading to sensors. It is even possible to combine different input currents and/or external parameters according to AND/OR logics. The currents through a clustered layer on a TEMPOS structure can be described by the Barbasi-Albert model of network theory enabling to calculate a 'radius of influence'r{sub ROI} around each surface contact, beyond which neighboring contacts do not influence each other. The radius of influence can be well below 1{mu}m leading to nanometric TEMPOS structures.

  12. Spin orbit torque based electronic neuron

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, Abhronil, E-mail: asengup@purdue.edu; Choday, Sri Harsha; Kim, Yusung; Roy, Kaushik [School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2015-04-06

    A device based on current-induced spin-orbit torque (SOT) that functions as an electronic neuron is proposed in this work. The SOT device implements an artificial neuron's thresholding (transfer) function. In the first step of a two-step switching scheme, a charge current places the magnetization of a nano-magnet along the hard-axis, i.e., an unstable point for the magnet. In the second step, the SOT device (neuron) receives a current (from the synapses) which moves the magnetization from the unstable point to one of the two stable states. The polarity of the synaptic current encodes the excitatory and inhibitory nature of the neuron input and determines the final orientation of the magnetization. A resistive crossbar array, functioning as synapses, generates a bipolar current that is a weighted sum of the inputs. The simulation of a two layer feed-forward artificial neural network based on the SOT electronic neuron shows that it consumes ∼3× lower power than a 45 nm digital CMOS implementation, while reaching ∼80% accuracy in the classification of 100 images of handwritten digits from the MNIST dataset.

  13. 8th international workshop on microbeam probes of cellular radiation response. Extended abstracts

    International Nuclear Information System (INIS)

    This meeting has been held regularly since 1993. In the past, these workshops have been highly successful in bringing together groups interested in developing and applying micro-irradiation techniques to the study of cell and tissue damage by ionizing radiations. Advances in microbeam technology are continuously occurring and have greatly contributed to the studies in various fields of life sciences in ways that can not be achieved using conventional broad field exposures. Microbeam irradiation can inactivate subcellular compartments and cell/tissue sub-populations, and can be used to investigate the spatial dynamics of sub-nuclear irradiation-induced DNA damage repair and non-targeted responses such as bystander effects, or as a tool in radio-microsurgery in eukaryotes including plants, silkworm, and nematode. At the last meeting held in 2006, about 30 microbeams were reported in operation or under development in the world. Now, only also in Tokyo metropolitan area, several different microbeams, using protons, heavy charged particles, synchrotron and Al-K X-rays, are available for cell-targeting irradiation. This Workshop will provide a forum to assess the current state of microbeam technology and current biological applications, and to discuss future directions for development, both technological and biological. (author)

  14. Higher order modes excitation of electrostatically actuated clamped–clamped microbeams: experimental and analytical investigation

    International Nuclear Information System (INIS)

    In this study, we demonstrate analytically and experimentally the excitations of the higher order modes of vibrations in electrostatically actuated clamped–clamped microbeam resonators. The concept is based on using partial electrodes with shapes that induce strong excitation of the mode of interest. The devices are fabricated using polyimide as a structural layer coated with nickel from the top and chrome and gold layers from the bottom. Experimentally, frequency sweeps with different electro-dynamical loading conditions are shown to demonstrate the excitation of the higher order modes of vibration. Using a half electrode, the second mode is excited with high amplitude of vibration compared with almost zero response using the full electrode. Also, using a two-third electrode configuration is shown to amplify the third mode resonance amplitude compared with the full electrode under the same electrical loading conditions. An analytical model is developed based on the Euler–Bernollui beam model and the Galerkin method to simulate the device response. Good agreement between the simulation results and the experimental data is reported. (paper)

  15. Bystander effect studies using heavy-ion microbeam

    International Nuclear Information System (INIS)

    We have established a single cell irradiation system, which allows selected cells to be individually hit with defined number of heavy charged particles, using a collimated heavy-ion microbeam apparatus at JAEA-Takasaki. This system has been developed to study radiobiological processes in hit cells and bystander cells exposed to low dose and low dose-rate high-LET radiations, in ways that cannot be achieved using conventional broad-field exposures. Individual cultured cells grown in special dishes were irradiated in the atmosphere with a single or defined numbers of 18.3 MeV/amu 12C, 13.0 or 17.5 MeV/amu 20Ne, and 11.5 MeV/amu 40Ar ions. Targeting and irradiation of the cells were performed automatically according to the positional data of the target cells microscopically obtained before irradiation. The actual number of particle tracks that pass through target cells was detected with prompt etching of the bottom of the cell dish made of ion track detector TNF-1 (modified CR-39). (author)

  16. Quantitative analysis of biomedical samples using synchrotron radiation microbeams

    Science.gov (United States)

    Ektessabi, Ali; Shikine, Shunsuke; Yoshida, Sohei

    2001-07-01

    X-ray fluorescence (XRF) using a synchrotron radiation (SR) microbeam was applied to investigate distributions and concentrations of elements in single neurons of patients with neurodegenerative diseases. In this paper we introduce a computer code that has been developed to quantify the trace elements and matrix elements at the single cell level. This computer code has been used in studies of several important neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and parkinsonism-dementia complex (PDC), as well as in basic biological experiments to determine the elemental changes in cells due to incorporation of foreign metal elements. The substantial nigra (SN) tissue obtained from the autopsy specimens of patients with Guamanian parkinsonism-dementia complex (PDC) and control cases were examined. Quantitative XRF analysis showed that neuromelanin granules of Parkinsonian SN contained higher levels of Fe than those of the control. The concentrations were in the ranges of 2300-3100 ppm and 2000-2400 ppm respectively. On the contrary, Zn and Ni in neuromelanin granules of SN tissue from the PDC case were lower than those of the control. Especially Zn was less than 40 ppm in SN tissue from the PDC case while it was 560-810 ppm in the control. These changes are considered to be closely related to the neuro-degeneration and cell death.

  17. The ionoluminescence apparatus at the LABEC external microbeam facility

    Energy Technology Data Exchange (ETDEWEB)

    Calusi, S.; Colombo, E. [INFN Sezione di Torino, Via P.Giuria 1, 10125 Torino (Italy); Dipartimento di Fisica Sperimentale and NIS Excellence Centre, Universita di Torino, Via P. Giuria 1, 10125 Torino (Italy); Giuntini, L. [Dipartimento di Fisica, Universita and INFN Sezione di Firenze, Via Sansone 1, 50019, Sesto Fiorentino, Firenze (Italy)], E-mail: giuntini@fi.infn.it; Giudice, A. Lo [Dipartimento di Fisica Sperimentale and NIS Excellence Centre, Universita di Torino, Via P. Giuria 1, 10125 Torino (Italy); Manfredotti, C. [INFN Sezione di Torino, Via P.Giuria 1, 10125 Torino (Italy); Dipartimento di Fisica Sperimentale and NIS Excellence Centre, Universita di Torino, Via P. Giuria 1, 10125 Torino (Italy); Massi, M. [Dipartimento di Fisica, Universita and INFN Sezione di Firenze, Via Sansone 1, 50019, Sesto Fiorentino, Firenze (Italy); Pratesi, G. [Dipartimento di Scienze della Terra and Museo di Storia Naturale, Universita di Firenze, Via G. La Pira 4, 50121 Firenze (Italy); Vittone, E. [INFN Sezione di Torino, Via P.Giuria 1, 10125 Torino (Italy); Dipartimento di Fisica Sperimentale and NIS Excellence Centre, Universita di Torino, Via P. Giuria 1, 10125 Torino (Italy)

    2008-05-15

    In this paper, we describe the main features of the ionoluminescence (IL) apparatus recently installed at the external scanning microbeam facility of the 3 MV Tandetron accelerator of the INFN LABEC Laboratory in Firenze. The peculiarity of this IL set-up resides in the fact that the light produced by the ion irradiation of the specimen is collected by a bifurcated optical fiber, so that photons are shunted both to a CCD spectrometer, working in the 200-900 nm wavelength range, and to a photomultiplier (PMT). The accurate focusing of the optical system allows high photon collection efficiency and this results in rapid acquisition of luminescence spectra with low ion currents on luminescent materials; simultaneously, luminescence maps with a spatial resolution of 10 {mu}m can be acquired through the synchronization of PMT photon detection with the position of the scanning focused ion beam. An optical filter with a narrow passband facing the photomultiplier allows chromatic selectivity of the luminescence centres. The IL apparatus is synergistically integrated into the existing set-up for ion beam analyses (IBA). The upgraded system permits simultaneous IL and PIXE/PIGE/BS measurements. With our integrated system, we have been studying raw lapis lazuli samples of different known origins and precious lapis lazuli artworks of the Collezione Medicea of Museum of Natural History, University of Firenze, aiming at characterising their composition and provenance.

  18. A microbeam slit system for high beam currents

    Science.gov (United States)

    Vallentin, T.; Moser, M.; Eschbaumer, S.; Greubel, C.; Haase, T.; Reichart, P.; Rösch, T.; Dollinger, G.

    2015-04-01

    A new microbeam slit system for high beam currents of 10 μA was built up to improve the brightness transport of a proton beam with a kinetic energy of up to 25 MeV into the microprobe SNAKE. The new slit system features a position accuracy of less than 1 μm under normal operating conditions and less than 2 μm if the beam is switched on and off. The thermal management with a powerful watercooling and potential-free thermocouple feedback controlled heating cables is optimized for constant slit aperture at thermal power input of up to 250 W. The transparent zone is optimized to 0.7 μm due to the use of tungsten formed to a cylindrical surface with a radius r = 100 mm and mechanically lapped surface to minimize small angle scattering effects and to minimize the number of ions passing the slits with low energy loss. Electrical isolation of the slit tip enables slit current monitoring, e.g. for tandem accelerator feedback control. With the ability to transport up to 10 μA of protons with the new microslit system, the brightness Bexp transported into the microprobe was increased by a factor of 2 compared to low current injection using the old slit system.

  19. The ionoluminescence apparatus at the LABEC external microbeam facility

    Science.gov (United States)

    Calusi, S.; Colombo, E.; Giuntini, L.; Giudice, A. Lo; Manfredotti, C.; Massi, M.; Pratesi, G.; Vittone, E.

    2008-05-01

    In this paper, we describe the main features of the ionoluminescence (IL) apparatus recently installed at the external scanning microbeam facility of the 3 MV Tandetron accelerator of the INFN LABEC Laboratory in Firenze. The peculiarity of this IL set-up resides in the fact that the light produced by the ion irradiation of the specimen is collected by a bifurcated optical fiber, so that photons are shunted both to a CCD spectrometer, working in the 200-900 nm wavelength range, and to a photomultiplier (PMT). The accurate focusing of the optical system allows high photon collection efficiency and this results in rapid acquisition of luminescence spectra with low ion currents on luminescent materials; simultaneously, luminescence maps with a spatial resolution of 10 μm can be acquired through the synchronization of PMT photon detection with the position of the scanning focused ion beam. An optical filter with a narrow passband facing the photomultiplier allows chromatic selectivity of the luminescence centres. The IL apparatus is synergistically integrated into the existing set-up for ion beam analyses (IBA). The upgraded system permits simultaneous IL and PIXE/PIGE/BS measurements. With our integrated system, we have been studying raw lapis lazuli samples of different known origins and precious lapis lazuli artworks of the Collezione Medicea of Museum of Natural History, University of Firenze, aiming at characterising their composition and provenance.

  20. Fair Electronic Cash Based on Double Signatures

    Institute of Scientific and Technical Information of China (English)

    陈晓峰; 王常杰; 王育民

    2002-01-01

    In order to decrease crimes such as money laundering, blackmailing etc. inelectronic cash systems, fair electronic cash has been a major focus of academic research inelectronic commence. When a bank finds some dubious cash or owner, the trusted entity ortrustee can help him to revoke the anonymity of the cash. In the previous protocols, the trusteeknows all the information of the cash whether he is trusted or not, that is, he can trace the useror cash unconditionally. Furthermore, the dishonest trustee may deceive a user, which meansthat he may withdraw cash while tracing other users. Such cases are unfair to the honest users.A new fair electronic cash protocol based on untrustworthy trustees is proposed in thispaper. The key idea is that the coin structure should include the signatures of both the trusteeand the bank so that the trustee shares the information of the cash with the bank, while we donot use the secret sharing scheme. In contrast with the previous protocols, neither the trusteenor the bank can trace the money without the help of the other entity. In this way, the privacyof the user is protected furthest. Also, the trustee is off-line in the protocol, which meansthat he will not be involved in withdrawing the cash. Therefore, the protocol is efficient forimplementation.

  1. Multifrequency excitation of a clamped–clamped microbeam: Analytical and experimental investigation

    KAUST Repository

    Jaber, Nizar

    2016-03-14

    Using partial electrodes and a multifrequency electrical source, we present a large-bandwidth, large-amplitude clamped–clamped microbeam resonator excited near the higher order modes of vibration. We analytically and experimentally investigate the nonlinear dynamics of the microbeam under a two-source harmonic excitation. The first-frequency source is swept around the first three modes of vibration, whereas the second source frequency remains fixed. New additive and subtractive resonances are demonstrated. We illustrated that by properly tuning the frequency and amplitude of the excitation force, the frequency bandwidth of the resonator is controlled. The microbeam is fabricated using polyimide as a structural layer coated with nickel from the top and chromium and gold layers from the bottom. Using the Galerkin method, a reduced order model is derived to simulate the static and dynamic response of the device. A good agreement between the theoretical and experimental data are reported.

  2. Development of the CAS-LIBB single-particle microbeam for localized irradiation of living cells

    Institute of Scientific and Technical Information of China (English)

    WANG Xufei; XU Mingliang; WU Lijun; WANG Shaohu; FENG Huiyun; ZHAN Furu; PENG Shixiang; HU Chundong; ZHANG Shuqing; CHENG Jianjun; SHI Zhongtao; WANG Xiaohua; YUAN Hang; YUAN Haitao; YU Zengliang; CHEN Lianyun; HU Zhiwen; LI Jun; WU Yu; CHEN Bin; HU Suhua; ZHANG Jun

    2004-01-01

    A single-particle microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering (LIBB), Chinese Academy of Sciences (CAS). The system was designed to deliver a defined numbers of hydrogen ions, produced by a van de Graaff accelerator, in an energy range of 2.0-3.0 MeV, into an area smaller than that of the nucleus of an individual living cell. The beam is collimated by a borosilicate glass capillary that forms the beam-line exit. An integrated computer program recognizes the cells and locates them one by one over the microbeam exit for irradiation. We present technical details of the CAS-LIBB microbeam facility, particularly on the collimator, hardware, control program, as well as cell irradiation protocols available. Various factors contributing to the targeting and positioning precision are discussed along with accuracy measurement results.

  3. Diffraction cartography: applying microbeams to macromolecular crystallography sample evaluation and data collection.

    Science.gov (United States)

    Bowler, Matthew W; Guijarro, Matias; Petitdemange, Sebastien; Baker, Isabel; Svensson, Olof; Burghammer, Manfred; Mueller-Dieckmann, Christoph; Gordon, Elspeth J; Flot, David; McSweeney, Sean M; Leonard, Gordon A

    2010-08-01

    Crystals of biological macromolecules often exhibit considerable inter-crystal and intra-crystal variation in diffraction quality. This requires the evaluation of many samples prior to data collection, a practice that is already widespread in macromolecular crystallography. As structural biologists move towards tackling ever more ambitious projects, new automated methods of sample evaluation will become crucial to the success of many projects, as will the availability of synchrotron-based facilities optimized for high-throughput evaluation of the diffraction characteristics of samples. Here, two examples of the types of advanced sample evaluation that will be required are presented: searching within a sample-containing loop for microcrystals using an X-ray beam of 5 microm diameter and selecting the most ordered regions of relatively large crystals using X-ray beams of 5-50 microm in diameter. A graphical user interface developed to assist with these screening methods is also presented. For the case in which the diffraction quality of a relatively large crystal is probed using a microbeam, the usefulness and implications of mapping diffraction-quality heterogeneity (diffraction cartography) are discussed. The implementation of these techniques in the context of planned upgrades to the ESRF's structural biology beamlines is also presented.

  4. Vibration behavior of a viscoelastic composite microbeam under simultaneous electrostatic and piezoelectric actuation

    Science.gov (United States)

    Chitsaz Yazdi, F.; Jalali, A.

    2015-08-01

    In this paper, the static and dynamic response of a clamped-clamped viscoelastic nanocomposite microbeam under combined electrostatic and piezoelectric actuations is analyzed. The equations of motion of the system are derived using the Euler-Bernoulli beam theory, Kelvin-Voigt model and Hamilton principle. The nonlinear model for the system is studied by considering stretching of the mid-plane, a DC electrostatic force, an AC harmonic force and a DC piezoelectric actuation. The static deflection and natural frequency of the system is extracted, and the influence of system parameters on the primary resonance behavior of the system is studied. It is shown that, based on various electrostatic and piezoelectric excitations, hardening or softening behavior is expected. So, one can tune these voltages such that this highly nonlinear system behaves linearly close to resonance frequency. Also it is shown that damping characteristics of the system with viscoelastic material not only depends on the damping coefficient of the system, but also on its other parameters.

  5. Laser microbeam manipulation of cell morphogenesis growing in fungal hyphae

    Science.gov (United States)

    Bracker, Charles E.; Murphy, Douglas J.; Lopez-Franco, Rosamaria

    1997-05-01

    Laser microbeam irradiation at 820 nm predictably and reproducibly altered morphogenetic patterns in fungal cells. Optical tweezers were highly effective as localized, noninvasive, and largely nondestructive probes under precise spatial and temporal control. In growing hyphae, the position of the Spitzenkorper (a multicomponent complex containing mainly secretory vesicles in the hyphal apex), is correlated with the site of maximum cell expansion during tip growth. The Spitzenkorper was not trapped by the laser, but moved away from the trap, and could be `chased' around the cell by the laser beam. Consequently, the direction of cell elongation was readily changed by moving the Spitzenkorper. When the laser was held steady at the cytoplasmic surface immediately beside the Spitzenkorper, an adventitious branch hypha was initiated on the same side of the hypha, suggesting that unilateral disturbance of vesicle traffic initiated a new lateral Spitzenkorper and hyphal branch near the original hyphal apex. If moving vesicles were trapped by the laser beam and transported to a different area of the cytoplasm near the cell surface, the cell profile bulged where the vesicles were newly concentrated. Variations in the mode of vesicle transfer caused: (1) single and multiple bulges, (2) adventitious branch hyphae, (3) increased cell diameter, and (4) changing directions of hyphal elongation. Thus, laser tweezers emerge as a powerful tool for controlling patterns of cell morphogenesis. The findings strongly support the hypothesis that sites of vesicle concentration and release to the cell surface are important determinants of cell morphogenesis in fungi. This conclusion lends support to the basic premises of a modern mathematical model of hyphal tip growth (the hyphoid/VSC model) but does not in itself provide the information needed for a comprehensive and integrated explanation of the mechanism of cell growth in fungi.

  6. Nonlinear dynamic response of an electrically actuated imperfect microbeam resonator

    KAUST Repository

    Ruzziconi, Laura

    2013-08-04

    We present a study of the dynamic behavior of a MEMS device constituted of an imperfect clamped-clamped microbeam subjected to electrostatic and electrodynamic actuation. Our objective is to develop a theoretical analysis, which is able to describe and predict all the main relevant aspects of the experimental response. Extensive experimental investigation is conducted, where the main imperfections coming from microfabrication are detected and the nonlinear dynamics are explored at increasing values of electrodynamic excitation, in a neighborhood of the first symmetric resonance. The nonlinear behavior is highlighted, which includes ranges of multistability, where the non-resonant and the resonant branch coexist, and intervals where superharmonic resonances are clearly visible. Numerical simulations are performed. Initially, two single mode reduced-order models are considered. One is generated via the Galerkin technique, and the other one via the combined use of the Ritz method and the Padé approximation. Both of them are able to provide a satisfactory agreement with the experimental data. This occurs not only at low values of electrodynamic excitation, but also at higher ones. Their computational efficiency is discussed in detail, since this is an essential aspect for systematic local and global simulations. Finally, the theoretical analysis is further improved and a two-degree-of-freedom reduced-order model is developed, which is capable also to capture the measured second symmetric superharmonic resonance. Despite the apparent simplicity, it is shown that all the proposed reduced-order models are able to describe the experimental complex nonlinear dynamics of the device accurately and properly, which validates the proposed theoretical approach. Copyright © 2013 by ASME.

  7. High-energy attosecond nanoplasmonic-based electron gun

    Science.gov (United States)

    Greig, S. R.; Elezzabi, A. Y.

    2016-03-01

    We present the design of an ultrafast conical lens based nanoplasmonic electron gun. Through excitation with a radially polarized laser pulse, and a combination of magnetostatic and spatial filtering, high energy electron packets with attosecond durations can be achieved.

  8. Electronic structure of hybrid interfaces for polymer-based electronics

    International Nuclear Information System (INIS)

    The fundamentals of the energy level alignment at anode and cathode electrodes in organic electronics are described. We focus on two different models that treat weakly interacting organic/metal (and organic/organic) interfaces: the induced density of interfacial states model and the so-called integer charge transfer model. The two models are compared and evaluated, mainly using photoelectron spectroscopy data of the energy level alignment of conjugated polymers and molecules at various organic/metal and organic/organic interfaces. We show that two different alignment regimes are generally observed: (i) vacuum level alignment, which corresponds to the lack of vacuum level offsets (Schottky-Mott limit) and hence the lack of charge transfer across the interface, and (ii) Fermi level pinning where the resulting work function of an organic/metal and organic/organic bilayer is independent of the substrate work function and an interface dipole is formed due to charge transfer across the interface. We argue that the experimental results are best described by the integer charge transfer model which predicts the vacuum level alignment when the substrate work function is above the positive charge transfer level and below the negative charge transfer level of the conjugated material. The model further predicts Fermi level pinning to the positive (negative) charge transfer level when the substrate work function is below (above) the positive (negative) charge transfer level. The nature of the integer charge transfer levels depend on the materials system: for conjugated large molecules and polymers, the integer charge transfer states are polarons or bipolarons; for small molecules' highest occupied and lowest unoccupied molecular orbitals and for crystalline systems, the relevant levels are the valence and conduction band edges. Finally, limits and further improvements to the integer charge transfer model are discussed as well as the impact on device design. (topical review)

  9. Conducting polymer based biomolecular electronic devices

    Indian Academy of Sciences (India)

    B D Malhotra; Rahul Singhal

    2003-08-01

    Biomolecular electronics is rapidly evolving from physics, chemistry, biology, electronics and information technology. Organic materials such as proteins, pigments and conducting polymers have been considered as alternatives for carrying out the functions that are presently being performed by semiconductor silicon. Conducting polymers such as polypyrroles, polythiophenes and polyanilines have been projected for applications for a wide range of biomolecular electronic devices such as optical, electronic, drug-delivery, memory and biosensing devices. Our group has been actively working towards the application of conducting polymers to Schottky diodes, metal–insulator–semiconductor (MIS) devices and biosensors for the past 10 years. This paper is a review of some of the results obtained at our laboratory in the area of conducting polymer biomolecular electronics.

  10. Optimisation of X-ray emission from a laser plasma source for the realisation of microbeam in sub-keV region.

    Science.gov (United States)

    Di Paolo Emilio, M; Festuccia, R; Palladino, L

    2015-09-01

    In this work, the X-ray emission generated from a plasma produced by focusing Nd-YAG laser beam on the Mylar and Yttrium targets will be characterised. The goal is to reach the best condition that optimises the X-ray conversion efficiency at 500 eV (pre-edge of the Oxigen K-shell), strongly absorbed by carbon-based structures. The characteristics of the microbeam optical system, the software/hardware control and the preliminary measurements of the X-ray fluence will be presented. PMID:25969522

  11. Investigation of double strand breaks induced by alpha particle irradiation using C.N.B.G. microbeam in human keratinocytes

    International Nuclear Information System (INIS)

    To understand the mechanisms of interaction of ionizing radiation with living tissues exposed to low and protracted doses remains a major issue for risk evaluation. The response cannot be found in epidemiological studies because the only available data concern accidental exposures to high doses of radiation. The natural exposure represents the main source of exposure in the daily life, just before the medical sources (radiology, radiotherapy). In addition, this kind of exposure is very difficult to reproduce in vitro by irradiating cell lines. The method per preference is based on random irradiation of cell populations. The mean number of particles having traversed cells is then calculated on the basis of Poisson statistics. In addition to inevitable multiple impacts, the numerous potential intracellular targets (nuclei, cytoplasm), the indirect effects induced by the impact of particles on neighbouring cells or simply the extracellular targets, constitute phenomena that make more complex the interpretation of experimental data. A charged particle microbeam was developed at C.E.N.B.G. to perform the targeted irradiation of individual cells with a targeting precision of a few microns. It is possible to deliver a counted number of alpha particles down to the ultimate dose of one alpha per cell, to target predetermined cells and then to observe the response of the neighbouring cells. This facility has been validated during this work on human keratinocyte cells expressing a recombinant nuclear fluorescent protein (histone H2B-GFP). The combination of ion micro-beams with confocal microscopy and numeric quantitative analysis allowed the measurement of DNA double strand breaks via the phosphorylation of the histone H2A.X in individual cells. The mechanisms of DNA reparation and apoptosis induction were also in the scope of those studies. The experimental results obtained during this thesis validate the methodology we have developed by demonstrating the targeting

  12. The Dynamics of a Doubly Clamped Microbeam Near the Primary Resonance: Experimental and Analytical Investigation

    KAUST Repository

    Masri, Karim M.

    2016-01-20

    We present experimental and analytical investigation of the dynamics of a doubly clamped microbeam near its primary resonance. The microbeam is excited electrostatically by an electrode on the first half of the beam. These microbeams are fabricated using polyimide as structural layer coated with nickel from top and chromium and gold layers from bottom. A noise signal is applied to experimentally detect the natural frequencies. Then, frequency sweep tests are generated for various values of DC bias revealing hardening, transition, and softening behavior of the microbeam. We report for the first time the transition from lower stable state, to unstable state, and then to large stable state experimentally. A multi-mode Galerkin method is used to develop a reduced order model (ROM) of the beam. Shooting method is used to find the periodic motion and is utilized to generate frequency response curves. The curves show good agreement with the experimental results with hardening behavior at lower DC voltage then softening at higher voltage loads and dynamic pull-in. © Copyright 2015 by ASME.

  13. Identification of ancient textile fibres from Khirbet Qumran caves using synchrotron radiation microbeam diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Martin [Institut fuer Experimentelle und Angewandte Physik der Christian, Albrechts, Universitaet zu Kiel, Leibnizstr. 19, D-24098 Kiel (Germany)]. E-mail: mmueller@physik.uni-kiel.de; Murphy, Bridget [Institut fuer Experimentelle und Angewandte Physik der Christian, Albrechts, Universitaet zu Kiel, Leibnizstr. 19, D-24098 Kiel (Germany); Burghammer, Manfred [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex (France); Riekel, Christian [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex (France); Roberts, Mark [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom); Papiz, Miroslav [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom); Clarke, David [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom); Gunneweg, Jan [Institute of Archaeology, The Hebrew University of Jerusalem, Mount Scopus, Jerusalem (Israel); Pantos, Emmanuel [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom)

    2004-10-08

    Archaeological textiles fragments from the caves of Qumran in the Dead Sea region were investigated by means of X-ray microbeam diffraction on single fibres. This non-destructive technique made the identification of the used plant textile fibres possible. Apart from bast fibres (mainly flax), cotton was identified which was most unexpected in the archaeological context.

  14. Live cell imaging at the Munich ion microbeam SNAKE – a status report

    International Nuclear Information System (INIS)

    Ion microbeams are important tools in radiobiological research. Still, the worldwide number of ion microbeam facilities where biological experiments can be performed is limited. Even fewer facilities combine ion microirradiation with live-cell imaging to allow microscopic observation of cellular response reactions starting very fast after irradiation and continuing for many hours. At SNAKE, the ion microbeam facility at the Munich 14 MV tandem accelerator, a large variety of biological experiments are performed on a regular basis. Here, recent developments and ongoing research projects at the ion microbeam SNAKE are presented with specific emphasis on live-cell imaging experiments. An overview of the technical details of the setup is given, including examples of suitable biological samples. By ion beam focusing to submicrometer beam spot size and single ion detection it is possible to target subcellular structures with defined numbers of ions. Focusing of high numbers of ions to single spots allows studying the influence of high local damage density on recruitment of damage response proteins. The online version of this article (doi:10.1186/s13014-015-0350-7) contains supplementary material, which is available to authorized users

  15. Piezoelectric transduction of flexural modes in pre-stressed microbeam resonators

    NARCIS (Netherlands)

    Torri, G.B.; Janssen, N.M.A.; Zeng, Z.; Rottenberg, X.; Karabacak, D.M.; Vandecasteele, M.; Hoof, C.V.; Puers, R.; Tilmans, H.A.C.

    2014-01-01

    This paper reports on the optimization of the design of piezoelectric transducer elements integrated on doubly-clamped microbeam resonators utilized as (bio)chemical sensors. We report and emphasize the often forgotten influence of membrane stresses on defining the dimensions and optimal position of

  16. Influence of squeeze film damping on the higher-order modes of clamped–clamped microbeams

    KAUST Repository

    Alcheikh, N

    2016-05-06

    This paper presents an experimental study and a finite-element analysis of the effect of squeeze film damping on the resonance frequency and quality factor of the higher-order flexure vibrations modes of clamped-clamped microbeams. Viscoelastic and silicon nitride microbeams are fabricated and are electrostatically actuated by various electrode configurations to trigger the first, second, and third modes. The damping characteristic and the resonance frequency of these modes are examined for a wide range of gas pressure and electrostatic voltage loads. The results of the silicon nitride beams and viscoelastic beams are compared. It is found that the intrinsic material loss is the major dissipation mechanism at low pressure for the viscoelastic microbeams, significantly limiting their quality factor. It is also found that while the silicon nitride beams show higher quality factors at the intrinsic and molecular regimes of pressure, due to their low intrinsic loss, their quality factors near atmospheric pressure are lower than those of the viscoelastic microbeams. Further, the higher-order modes of all the beams show much higher quality factors at atmospheric pressure compared to the first mode, which could be promising for operating such resonators in air. Experimental results and finite element model simulations show good agreement for resonance frequency and quality factor for the three studied modes. © 2016 IOP Publishing Ltd.

  17. Electron Source based on Superconducting RF

    Science.gov (United States)

    Xin, Tianmu

    High-bunch-charge photoemission electron-sources operating in a Continuous Wave (CW) mode can provide high peak current as well as the high average current which are required for many advanced applications of accelerators facilities, for example, electron coolers for hadron beams, electron-ion colliders, and Free-Electron Lasers (FELs). Superconducting Radio Frequency (SRF) has many advantages over other electron-injector technologies, especially when it is working in CW mode as it offers higher repetition rate. An 112 MHz SRF electron photo-injector (gun) was developed at Brookhaven National Laboratory (BNL) to produce high-brightness and high-bunch-charge bunches for electron cooling experiments. The gun utilizes a Quarter-Wave Resonator (QWR) geometry for a compact structure and improved electron beam dynamics. The detailed RF design of the cavity, fundamental coupler and cathode stalk are presented in this work. A GPU accelerated code was written to improve the speed of simulation of multipacting, an important hurdle the SRF structure has to overcome in various locations. The injector utilizes high Quantum Efficiency (QE) multi-alkali photocathodes (K2CsSb) for generating electrons. The cathode fabrication system and procedure are also included in the thesis. Beam dynamic simulation of the injector was done with the code ASTRA. To find the optimized parameters of the cavities and beam optics, the author wrote a genetic algorithm Python script to search for the best solution in this high-dimensional parameter space. The gun was successfully commissioned and produced world record bunch charge and average current in an SRF photo-injector.

  18. An Internet Based Anonymous Electronic Cash System

    Directory of Open Access Journals (Sweden)

    Israt Jahan

    2015-04-01

    Full Text Available There is an increase activity in research to improve the current electronic payment system which is parallel with the progress of internet. Electronic cash system is a cryptographic payment system which offers anonymity during withdrawal and purchase. Electronic cash displays serial numbers which can be recorded to allow further tracing. Contrary to their physical counterparts, e-cash have an inherent limitation; they are easy to copy and reuse (double-spending. An observer is a tamper-resistant device, issued by the Internet bank, which is incorporated with the Internet user’s computer that prevents double-spending physically, i.e., the user has no access to her e-cash and therefore he cannot copy them. In this paper, we shall present an anonymous electronic cash scheme on the internet which incorporates tamper-resistant device with user-module.

  19. Introducing the ELMCIP Electronic Literature Knowledge Base

    OpenAIRE

    Rettberg, Scott

    2013-01-01

    Focusing on a particular creative community, of electronic literature practitioners, the central research question of the ELMCIP collaborative research project is how creative communities of practitioners form within transnational and transcultural contexts, within a globalised and distributed communications environment. We seek to gain insight into and understanding of the social effects and manifestations of creativity. Our research seeks to exploit the characteristics of electronic literat...

  20. 'BioQuaRT' project: design of a novel in situ protocol for the simultaneous visualisation of chromosomal aberrations and micronuclei after irradiation at microbeam facilities.

    Science.gov (United States)

    Patrono, C; Monteiro Gil, O; Giesen, U; Langner, F; Pinto, M; Rabus, H; Testa, A

    2015-09-01

    The aim of the 'BioQuaRT' (Biologically weighted Quantities in RadioTherapy) project is to develop measurement techniques for characterising charged particle track structure on different length scales, and to correlate at the cellular level the track structure properties with the biological effects of radiation. This multi-scale approach will allow characterisation of the radiation qualities used in radiotherapy and the related biological effects. Charged-particle microbeam facilities were chosen as the platforms for all radiobiology experiments in the 'BioQuaRT' project, because they allow targeting single cells (or compartments of a cell) with a predefined number of ionising particles and correlating the cell-by-cell induced damage with type and energy of the radiation and with the number of ions per cell. Within this project, a novel in situ protocol was developed for the analysis of the misrepaired and/or unrepaired chromosome damage induced by charged-particle irradiations at the Physikalisch-Technische Bundesanstalt (PTB) ion microbeam facility. Among the cytogenetic biomarkers to detect and estimate radiation-induced DNA damage in radiobiology, chromosomal aberrations and micronuclei were chosen. The characteristics of the PTB irradiation system required the design of a special in situ assay: specific irradiation dishes with a base made from a biofoil 25-µm thick and only 3000-4000 cells seeded and irradiated per dish. This method was developed on Chinese hamster ovary (CHO) cells, one of the most commonly used cell lines in radiobiology in vitro experiments. The present protocol allows the simultaneous scoring of chromosome aberrations and micronuclei on the same irradiated dish. Thanks to its versatility, this method could also be extended to other radiobiological applications besides the single-ion microbeam irradiations. PMID:25877532

  1. Microscopic residual stress evolution during deformation process of an Fe---Mn---Si---Cr shape memory alloy investigated using white X-ray microbeam diffraction

    International Nuclear Information System (INIS)

    Microscopic residual stress evolution in different austenite (γ) grains during shape memory process in an Fe---Mn---Si---Cr alloy was investigated using the white X-ray microbeam diffraction technique. The use of high-energy white X-ray microbeam with small beam size allowed us to measure the microscopic residual stress in coarse γ grains with specific orientation. After tensile deformation large compressive residual stress was evolved in γ grains due to the formation of stress-induced ε martensite, but upon recovery heating it almost disappeared as a result of reverse transformation of martensite. The magnitude of compressive residual stress was higher in grains with orientations close to 〈144〉 and 〈233〉 orientations than in a grain with near 〈001〉 orientation. Analysis of the microstructure of each grain using electron backscattering diffraction suggested that the difference in the magnitude of compressive residual stress could be attributed to different martensitic transformation characteristics in the grains

  2. Flexible, fpga-based electronics for modular robots

    DEFF Research Database (Denmark)

    Brandt, David; Larsen, Jørgen Christian; Christensen, David Johan;

    2008-01-01

    In this paper we introduce electronics for the ATRON self-reconfigurable robot based on field programmable gate arrays (FPGAs). The immediate advantage of using FPGAs is that some of the module’s electronics can be moved into the FPGA, thereby the number of components can be reduced. In the case...... the FPGA and therefore integrate task-specific electronics without physically changing the electronics or we can reconfigure the electronics for specific tasks. The disadvantages of an FPGA-based design include the cost of FPGAs, the extra layer of complexity in programming, and a limited increase in power...... consumption compared to micro-controllers. However, overall FPGAs make the electronics of modular robots more flexible and therefore may make them more suitable for real applications. AB - In this paper we introduce electronics for the ATRON self-reconfigurable robot based on field programmable gate arrays...

  3. An electrically actuated imperfect microbeam: Dynamical integrity for interpreting and predicting the device response

    KAUST Repository

    Ruzziconi, Laura

    2013-02-20

    In this study we deal with a microelectromechanical system (MEMS) and develop a dynamical integrity analysis to interpret and predict the experimental response. The device consists of a clamped-clamped polysilicon microbeam, which is electrostatically and electrodynamically actuated. It has non-negligible imperfections, which are a typical consequence of the microfabrication process. A single-mode reduced-order model is derived and extensive numerical simulations are performed in a neighborhood of the first symmetric natural frequency, via frequency response diagrams and behavior chart. The typical softening behavior is observed and the overall scenario is explored, when both the frequency and the electrodynamic voltage are varied. We show that simulations based on direct numerical integration of the equation of motion in time yield satisfactory agreement with the experimental data. Nevertheless, these theoretical predictions are not completely fulfilled in some aspects. In particular, the range of existence of each attractor is smaller in practice than in the simulations. This is because these theoretical curves represent the ideal limit case where disturbances are absent, which never occurs under realistic conditions. A reliable prediction of the actual (and not only theoretical) range of existence of each attractor is essential in applications. To overcome this discrepancy and extend the results to the practical case where disturbances exist, a dynamical integrity analysis is developed. After introducing dynamical integrity concepts, integrity profiles and integrity charts are drawn. They are able to describe if each attractor is robust enough to tolerate the disturbances. Moreover, they detect the parameter range where each branch can be reliably observed in practice and where, instead, becomes vulnerable, i.e. they provide valuable information to operate the device in safe conditions according to the desired outcome and depending on the expected disturbances

  4. Developing a model for application of electronic banking based on electronic trust

    Directory of Open Access Journals (Sweden)

    Amir Hooshang Nazarpoori

    2014-05-01

    Full Text Available This study develops a model for application of electronic banking based on electronic trust among costumers of Day bank in KhoramAbad city. A sample of 150 people was selected based on stratified random sampling. Questionnaires were used for the investigation. Results indicate that technology-based factors, user-based factors, and trust had negative relationships with perceived risk types including financial, functional, personal, and private. Moreover, trust including trust in system and trust in bank had a positive relationship with tendency to use and real application of electronic banking.

  5. Animation Based Learning of Electronic Devices

    Science.gov (United States)

    Gero, Aharon; Zoabi, Wishah; Sabag, Nissim

    2014-01-01

    Two-year college teachers face great difficulty when they teach the principle of operation of the bipolar junction transistor--a subject which forms the basis for electronics studies. The difficulty arises from both the complexity of the device and by the lack of adequate scientific background among the students. We, therefore, developed a unique…

  6. The Roads to LPA Based Free Electron Laser

    OpenAIRE

    Zhu, Xiongwei

    2014-01-01

    In this paper, we simply outline the present status of the free electron laser and the laser plasma based accelerator, and we simply discuss the potential possible roads appearing in the accelerator community to use the laser plasma based accelerator into the field of the free electron laser.

  7. EDITORIAL: Nanotechnology-based flexible electronics Nanotechnology-based flexible electronics

    Science.gov (United States)

    Subramanian, Vivek; Lee, Takhee

    2012-08-01

    Research on flexible electronics has grown exponentially over the last decade. Researchers around the globe are developing a wide range of flexible systems, including displays [1, 2], sensors [3-5], RFID tags [6, 7] and other similar devices [8]. Innovations in materials have been key to the increased research success in this field of research in recent years [9]. Transistors, interconnects, memory cells, passive components and other assorted devices all have challenging material demands for flexible electronics to become a reality. Nanomaterials of various kinds have been found to represent a tremendously powerful tool, with nanoparticles [10], nanotubes, nanowires [3, 11] and engineered organic molecules [12, 13] contributing to the realization of high-performance semiconductors, dielectrics and conductors for flexible electronics applications. Nanomaterials offer tunability in terms of performance, solution processability and processing temperature requirements, which makes them very attractive as building blocks for flexible electronic systems. Indeed, such systems represent some of the largest families of commercially produced nanomaterials today, and numerous commercial products based on nanoparticle formulations are widely available. This special issue focuses on the rapidly blossoming field of flexible electronics, with a particular focus on the use of nanotechnology to facilitate flexible electronic materials, processes, devices and systems. Contributions to the issue describe the development of nanomaterials—including nanoparticles, nanotubes, nanowires and carbon-based thin films—for use in conductors, transparent electrodes, semiconductors and dielectrics. The articles feature innovations in nanomanufacturing and novel materials, as well as the application of these technologies to advanced flexible devices and systems. As flexible electronics systems move rapidly towards successful commercial deployment, it is extremely likely that they will exploit

  8. Particle induced X-ray emission and ion dose distribution in a biological micro-beam: Geant4 Monte Carlo simulations

    International Nuclear Information System (INIS)

    The goal of a microbeam is to deliver a highly localized and small dose to the biological medium. This can be achieved by using a set of collimators that confine the charged particle beam to a very small spatial area of the order of microns in diameter. By using a system that combines an appropriate beam detection method that signals to a beam shut-down mechanism, a predetermined and counted number of energetic particles can be delivered to targeted biological cells. Since the shutter and the collimators block a significant proportion of the beam, there is a probability of the production of low energy X-rays and secondary electrons through interactions with the beam. There is little information in the biological microbeam literature on potential X-ray production. We therefore used Monte Carlo simulations to investigate the potential production of particle-induced X-rays and secondary electrons in the collimation system (which is predominantly made of tungsten) and the subsequent possible effects on the total absorbed dose delivered to the biological medium. We found, through the simulation, no evidence of the escape of X-rays or secondary electrons from the collimation system for proton energies up to 3 MeV as we found that the thickness of the collimators is sufficient to reabsorb all of the generated low energy X-rays and secondary electrons. However, if the proton energy exceeds 3 MeV our simulations suggest that 10 keV X-rays can escape the collimator and expose the overlying layer of cells and medium. If the proton energy is further increased to 4.5 MeV or beyond, the collimator can become a significant source of 10 keV and 59 keV X-rays. These additional radiation fields could have effects on cells and these results should be verified through experimental measurement. We suggest that researchers using biological microbeams at higher energies need to be aware that cells may be exposed to a mixed LET radiation field and be careful in their interpretation of

  9. Graph-based linear scaling electronic structure theory.

    Science.gov (United States)

    Niklasson, Anders M N; Mniszewski, Susan M; Negre, Christian F A; Cawkwell, Marc J; Swart, Pieter J; Mohd-Yusof, Jamal; Germann, Timothy C; Wall, Michael E; Bock, Nicolas; Rubensson, Emanuel H; Djidjev, Hristo

    2016-06-21

    We show how graph theory can be combined with quantum theory to calculate the electronic structure of large complex systems. The graph formalism is general and applicable to a broad range of electronic structure methods and materials, including challenging systems such as biomolecules. The methodology combines well-controlled accuracy, low computational cost, and natural low-communication parallelism. This combination addresses substantial shortcomings of linear scaling electronic structure theory, in particular with respect to quantum-based molecular dynamics simulations. PMID:27334148

  10. Graph-based linear scaling electronic structure theory

    CERN Document Server

    Niklasson, Anders M N; Negre, Christian F A; Cawkwell, Marc J; Swart, Pieter J; Mohd-Yusof, Jamal; Germann, Timothy C; Wall, Michael E; Bock, Nicolas; Djidjev, Hristo

    2016-01-01

    We show how graph theory can be combined with quantum theory to calculate the electronic structure of large complex systems. The graph formalism is general and applicable to a broad range of electronic structure methods and materials, including challenging systems such as biomolecules. The methodology combines well-controlled accuracy, low computational cost, and natural low-communication parallelism. This combination addresses substantial shortcomings of linear scaling electronic structure theory, in particular with respect to quantum-based molecular dynamics simulations.

  11. Simultaneous ion luminescence imaging and spectroscopy of individual aerosol particles with external proton or helium microbeams

    Energy Technology Data Exchange (ETDEWEB)

    Kada, Wataru, E-mail: kada.wataru@gunma-u.ac.jp [Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); Satoh, Takahiro; Yokoyama, Akihito; Koka, Masashi; Kamiya, Tomihiro [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

    2014-08-01

    Simultaneous microscopic imaging and spectroscopy of individual aerosol particles were performed with an external microbeam. Visible luminescence induced by the external microbeam was successfully used as a probe to detect organic contaminants in the targets. Combined ion luminescence (IL)/particle-induced X-ray emission (PIXE) analysis of the aerosol targets revealed microscopic chemical and elemental composition distributions under ambient atmospheric conditions. The simple confocal micro-optics for the IL spectroscopy and microscopic imaging were sufficiently sensitive for detecting these molecules at sub-parts per million concentrations and at a wavelength resolution of less than 5 nm. The IL spectra were monitored to prevent severe damage to the samples. Furthermore, our IL system has the advantage that it is simple to add to a conventional micro-PIXE system.

  12. Nonlinear static and dynamic responses of an electrically actuated viscoelastic microbeam

    Institute of Scientific and Technical Information of China (English)

    Y. M. Fu; J. Zhang

    2009-01-01

    On the basis of the Euler-Bernoulli hypothesis,nonlinear static and dynamic responses of a viscoelastic microbeam under two kinds of electric forces [a purely direct current (DC) and a combined current composed of a DC and an alternating current] are studied. By using Taylor series expansion, a governing equation of nonlinear integro-differential type is derived, and numerical analyses are performed.When a purely DC is applied, there exist an instantaneous pull-in voltage and a durable pull-in voltage of which the physical meanings are also given, whereas under an applied combined current, the effect of the element relaxation coefficient on the dynamic pull-in phenomenon is observed where the largest Lyapunov exponent is taken as a criterion for the dynamic pull-in instability of viscoelastic microbeams.

  13. Accuracy Measurements of the CAS-LIBB Single-Particle Microbeam for Single Cell Irradiation

    Institute of Scientific and Technical Information of China (English)

    WANG Xu-Fei; WU Li-Jun; YU Zeng-Liang; HU Zhi-Wen; WANG Xiao-Hua; CHEN Lian-Yun; ZHANG Jun; LI Jun; CHEN Bin; XU Ming-Liang; WU Yu

    2004-01-01

    A single-particle microbeam facility has been constructed at the Laboratory ofIon Beam Bioengineering (LIBB),Chinese Academy of Sciences. The system is designed to deliver the defined number of hydrogen ions, covering a range of energy from 1.0 to 3.5 MeV, into an area smaller than the nuclei of individual living cells. Accuracy of the particle detection system and the cell targeting system in the facility has been assessed using CR39 (nuclear track detector) for 2.3 MeV protons. The results demonstrate that the particle detection efficiency is above 98%,and the overall targeting accuracy of the microbeam is limited within 3μm for more than 90% hits.

  14. Distribution and anisotropy of dislocations in cold-drawn pearlitic steel wires analyzed using micro-beam X-ray diffraction

    International Nuclear Information System (INIS)

    To characterize the distribution and anisotropy of dislocations in cold-drawn pearlitic steel wires, X-ray diffraction line-profile analysis was performed using synchrotron radiation micro-beams. An analytical procedure for correcting the instrumental line broadening for highly directional micro-beams was developed using diffraction profiles of standard CeO2 powder. Although the CeO2 powder line profile includes line broadening due to its microstructural imperfections, the instrumental broadening can be obtained by estimating the effect of the microstructural imperfections on the line broadening. The plastic shear strain was generally more severe near the surface than the center of the wire, whereas the dislocation density distribution was almost constant from the center to the surface. On the other hand, the dislocation rearrangement, which evolves the dislocation cell structure, progressed closer to the surface. It was also revealed that a difference between the hardness in axial and transverse wire directions could be explained by anisotropic dislocation density. Line-profile analysis based on diffraction data at elevated temperatures was performed. Whereas the cementite recovery progressed at a constant rate, the ferrite phase recovery rate was temperature-dependent, suggesting that the ferrite phase recovery was less related to that of the cementite phase. (author)

  15. Synaptic devices based on purely electronic memristors

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Ruobing [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Li, Jun; Zhuge, Fei, E-mail: zhugefei@nimte.ac.cn, E-mail: h-cao@nimte.ac.cn; Zhu, Liqiang; Liang, Lingyan; Zhang, Hongliang; Gao, Junhua; Cao, Hongtao, E-mail: zhugefei@nimte.ac.cn, E-mail: h-cao@nimte.ac.cn; Fu, Bing; Li, Kang [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2016-01-04

    Memristive devices have been widely employed to emulate biological synaptic behavior. In these cases, the memristive switching generally originates from electrical field induced ion migration or Joule heating induced phase change. In this letter, the Ti/ZnO/Pt structure was found to show memristive switching ascribed to a carrier trapping/detrapping of the trap sites (e.g., oxygen vacancies or zinc interstitials) in ZnO. The carrier trapping/detrapping level can be controllably adjusted by regulating the current compliance level or voltage amplitude. Multi-level conductance states can, therefore, be realized in such memristive device. The spike-timing-dependent plasticity, an important Hebbian learning rule, has been implemented in this type of synaptic device. Compared with filamentary-type memristive devices, purely electronic memristors have potential to reduce their energy consumption and work more stably and reliably, since no structural distortion occurs.

  16. Synaptic devices based on purely electronic memristors

    Science.gov (United States)

    Pan, Ruobing; Li, Jun; Zhuge, Fei; Zhu, Liqiang; Liang, Lingyan; Zhang, Hongliang; Gao, Junhua; Cao, Hongtao; Fu, Bing; Li, Kang

    2016-01-01

    Memristive devices have been widely employed to emulate biological synaptic behavior. In these cases, the memristive switching generally originates from electrical field induced ion migration or Joule heating induced phase change. In this letter, the Ti/ZnO/Pt structure was found to show memristive switching ascribed to a carrier trapping/detrapping of the trap sites (e.g., oxygen vacancies or zinc interstitials) in ZnO. The carrier trapping/detrapping level can be controllably adjusted by regulating the current compliance level or voltage amplitude. Multi-level conductance states can, therefore, be realized in such memristive device. The spike-timing-dependent plasticity, an important Hebbian learning rule, has been implemented in this type of synaptic device. Compared with filamentary-type memristive devices, purely electronic memristors have potential to reduce their energy consumption and work more stably and reliably, since no structural distortion occurs.

  17. Genetic changes induced in higher plant cells by a laser microbeam

    International Nuclear Information System (INIS)

    Introducing foreign genes into higher plants has proved to be complicated, with the exception of transformation of protoplasts of some plants (Negrutiu et al. 1987). In particular, culture of protoplasts and regeneration to plants are difficult in many monocotyledonous crops. Therefore, it would be desirable to avoid extensive tissue culture by introducing cloned genes directly into cells. A laser microbeam can perforate plant cell walls, thus facilitating uptake of genes into cells

  18. Microbeam PIXE analysis of platinum resistant and sensitive ovarian cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Jeynes, J.C.G., E-mail: J.C.Jeynes@surrey.ac.u [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Bailey, M.J. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Coley, H. [Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom); Kirkby, K.J.; Jeynes, C. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2010-06-15

    Microbeam PIXE was used to analyse platinum in single ovarian cancer cells. Carboplatin sensitive and resistant cells were grown as a monolayer on polypropylene and treated with either carboplatin or cisplatin. Pt from the carboplatin could not be detected. The Pt from cisplatin in the cells could be detected, and significantly more Zn was found in the resistant cells compared to the sensitive cells. The sensitive cells probably accumulated more cisplatin than the resistant ones.

  19. Using Electronic Resources to Support Problem-Based Learning

    Science.gov (United States)

    Chang, Chen-Chi; Jong, Ay; Huang, Fu-Chang

    2012-01-01

    Students acquire skills in problem solving and critical thinking through the process as well as team work on problem-based learning courses. Many courses have started to involve the online learning environment and integrate these courses with electronic resources. Teachers use electronic resources in their classes. To overcome the problem of the…

  20. A generic converter for experimentation based power electronics learning

    OpenAIRE

    Leite, V; Barbosa, José; Teixeira, H.; Araújo, R.

    2005-01-01

    This paper presents a low cost, modular, configurable and fully protected education tool based on a generic electronic converter to be used by students, providing them with skills regarding power electronics and converters, and enabling them to learn from experience the most important issues concerning DC and AC electric drives.

  1. Development of micro-optics for high-resolution IL spectroscopy with a proton microbeam probe

    Energy Technology Data Exchange (ETDEWEB)

    Kada, Wataru, E-mail: kada.wataru@gunma-u.ac.jp [Faculty of Science and Technology, Gunma University, 1-5-1 Tenjin-machi, Kiryu, Gunma 376-8515 (Japan); Satoh, Takahiro; Yokoyama, Akihito; Koka, Masashi; Kamiya, Tomihiro [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

    2014-01-01

    Confocal optics for ion luminescence (IL) was developed for the precise analysis of the chemical composition of microscopic targets with an external proton microbeam probe. Anti-reflection-coated confocal micro-lens optics with an effective focus area of approximately 800 × 800 μm was installed on the microbeam line of a single-ended accelerator. Chromatic aberrations of the confocal optics were examined at wavelengths of 300–900 nm. An electrically-cooled back-thinned charge coupled device spectrometer with a wavelength resolution of 0.5 nm was used for the microscopic spectroscopy and IL imaging of microscopic mineral targets. Simultaneous microscopic IL and micro-PIXE analysis were performed using an external 3 MeV H{sup +} microbeam with a current of less than 100 pA. A spectral resolution of 3 nm was achieved for a single IL peak which corresponded to Cr{sup 3+} impurities in a single-crystal of aluminum oxide. The use of IL spectroscopy and imaging for aerosol targets revealed microscopic distributions of the chemical and elemental composition in the atmosphere.

  2. X-ray microbeams: Tumor therapy and central nervous system research

    International Nuclear Information System (INIS)

    Irradiation with parallel arrays of thin, planar slices of X-ray beams (microplanar beams, or microbeams) spares normal tissue, including the central nervous system (CNS), and preferentially damages tumors. The effects are mediated, at least in part, by the tissue's microvasculature that seems to effectively repair itself in normal tissue but fails to do so in tumors. Consequently, the therapeutic index of single-fraction unidirectional microbeam irradiations has been shown to be larger than that of single-fraction unidirectional unsegmented beams in treating the intracranial rat 9L gliosarcoma tumor model (9LGS) and the subcutaneous murine mammary carcinoma EMT-6. This paper presents results demonstrating that individual microbeams, or arrays of parallel ones, can also be used for targeted, selective cell ablation in the CNS, and also to induce demyelination. The results highlight the value of the method as a powerful tool for studying the CNS through selective cell ablation, besides its potential as a treatment modality in clinical oncology

  3. Calibration Base Lines for Electronic Distance Measuring Instruments (EDMI)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A calibration base line (CBL) is a precisely measured, straight-line course of approximately 1,400 m used to calibrate Electronic Distance Measuring Instruments...

  4. Electronic Commerce Logistics Network Optimization Based on Swarm Intelligent Algorithm

    Directory of Open Access Journals (Sweden)

    Yabing Jiao

    2013-09-01

    Full Text Available This article establish an efficient electronic commerce logistics operation system to reduce distribution costs and build a logistics network operation model based on around the B2C electronic commerce enterprise logistics network operation system. B2C electronic commerce transactions features in the enterprise network platform. To solve the NP-hard problem this article use hybrid ant colony algorithm, particle swarm algorithm and group swarm intelligence algorithm to get a best solution. According to the intelligent algorithm, design of electronic commerce logistics network optimization system, enter the national 22 electronic commerce logistics network for validation. Through the experiment to verify the optimized logistics cost greatly decreased. This research can help B2C electronic commerce enterprise logistics network to optimize decision-making under the premise of ensuring the interests of consumers and service levels also can be an effective way for enterprises to improve the efficiency of logistics services and reduce operation costs

  5. A Novel Calibrator for Electronic Transformers Based on IEC 61850

    Directory of Open Access Journals (Sweden)

    Baoxiang PAN

    2013-01-01

    Full Text Available It is necessary for electronic transformer to make calibration before putting it into practice. To solve the problems in actual calibration process, a novel electronic transformer calibrator is designed. In principle, this system adopts both the direct method and the difference method, which are two popular methods for electronic transformer calibration, by this way the application of the system is extended with its reliability improved. In the system design, based on virtual instrument technology, LabVIEW and WinPCap toolkit are used to develop the application software, and it is able to calibrate those electronic transformers following the standard of IEC 61850. In the calculation of ratio and phase error based on fast Fourier transform, a new window function is introduced, and thus the accuracy of calibration, influenced by the frequency vibration, is improved. This research provides theoretic support and practical reference to the development of intelligent calibrator for electronic transformers.

  6. 3 dimensional ionospheric electron density reconstruction based on GPS measurements

    Science.gov (United States)

    Stolle, C.; Schlüter, S.; Jacobi, C.; Jakowski, N.

    When radio waves as sended by the naviagtion system GPS are passing through the ionosphere they are subject to delays in phase, travel time and polarisation which is an effect of the free electrons. The measured integrated value of Total Electron Content can be utilised for three-dimensional reconstruction of electron density patterns in the ionosphere. Here a tomographic approach is represented. Scince the distribution of data is very sparse and patchy we decided for an algebraic iterative algorithm. The ground based GPS data collected by IGS receivers can be combined by space based GPS of radio limb sounding, incoherent scatter radar and ionosondes data. Hereby, radio occultation data improve beside the amount of available data especially the vertical resolution of electron density distribution. Ionosonde peack electron densities are taken as stop criteria determination for iteration. Reconstructed ionospheric scenarios and validations of the system by independent measurements are presented.

  7. Chemical Functionalization Effects on Cubane-Based Chain Electronic Transport

    Directory of Open Access Journals (Sweden)

    Konstantin P. Katin

    2015-01-01

    Full Text Available We report electronic structure calculations in chemically functionalized linear cubane-based chains. The effects of covalent chemical attachments on chain transport properties are examined with nonorthogonal tight-binding model (NTBM considering Landauer-Büttiker formalism. The covalent bonding of even a single-type functional group is shown to considerably alter the conductance of the chain. For similar radical doping density, electronic characteristics are found to range from insulator to narrow-gap semiconductor depending on the nature of the covalent bonding. Therefore it has become possible to tune electronic properties of the cubane-based one-dimensional oligomers by the functionalization for nanoelectronic applications.

  8. Controlled cooling of an electronic system based on projected conditions

    Science.gov (United States)

    David, Milnes P.; Iyengar, Madhusudan K.; Schmidt, Roger R.

    2015-08-18

    Energy efficient control of a cooling system cooling an electronic system is provided based, in part, on projected conditions. The control includes automatically determining an adjusted control setting(s) for an adjustable cooling component(s) of the cooling system. The automatically determining is based, at least in part, on projected power consumed by the electronic system at a future time and projected temperature at the future time of a heat sink to which heat extracted is rejected. The automatically determining operates to reduce power consumption of the cooling system and/or the electronic system while ensuring that at least one targeted temperature associated with the cooling system or the electronic system is within a desired range. The automatically determining may be based, at least in part, on an experimentally obtained model(s) relating the targeted temperature and power consumption of the adjustable cooling component(s) of the cooling system.

  9. Controlled cooling of an electronic system based on projected conditions

    Energy Technology Data Exchange (ETDEWEB)

    David, Milnes P.; Iyengar, Madhusudan K.; Schmidt, Roger R.

    2016-05-17

    Energy efficient control of a cooling system cooling an electronic system is provided based, in part, on projected conditions. The control includes automatically determining an adjusted control setting(s) for an adjustable cooling component(s) of the cooling system. The automatically determining is based, at least in part, on projected power consumed by the electronic system at a future time and projected temperature at the future time of a heat sink to which heat extracted is rejected. The automatically determining operates to reduce power consumption of the cooling system and/or the electronic system while ensuring that at least one targeted temperature associated with the cooling system or the electronic system is within a desired range. The automatically determining may be based, at least in part, on an experimentally obtained model(s) relating the targeted temperature and power consumption of the adjustable cooling component(s) of the cooling system.

  10. The preclinical set-up at the ID17 biomedical beamline to achieve high local dose deposition using interlaced microbeams

    Science.gov (United States)

    Bräuer-Krisch, E.; Nemoz, C.; Brochard, Th; Berruyer, G.; Renier, M.; Pouyatos, B.; Serduc, R.

    2013-03-01

    Microbeam Radiation Therapy (MRT) uses spatially a fractionated "white beam" (energies 50-350 keV) irradiation from a Synchrotron Source. The typical microbeams used at ID17 are 25-100μm-thick, spaced by 200-400μm, and carry extremely high dose rates (up to about 16 kGy/s). These microbeams are well tolerated by biological tissue, i.e. up to several hundred of Gy in the peaks. When valley doses, caused by Compton scattering in between two microbeams, remain within a dose regime similar to conventional RT, a superior tumour control can be achieved with MRT than with conventional RT. The normal tissue tolerance of these microscopically small beams is outstanding and well documented in the literature. The hypothesis of a differential effect in particular on the vasculature of normal versus tumoral tissue might best be proven by using large animal models with spontaneous tumors instead of small laboratory animals with transplantable tumors, an ongoing project on ID17. An alternative approach to deposit a high dose, while preserving the feature of the spatial separation of these microbeams outside the target has opened up new applications in preclinical research. The instrumentation of this method to produce such interlaced beams is presented with an outlook on the challenges to build a treatment platform for human patients. Dose measurements using Gafchromic films exposed in interlaced geometries with their steep profiles highlight the potential to deposit radiotoxic doses in the vicinity of radiosensitive tissues.

  11. Compact electron gun based on secondary emission through ionic bombardment.

    Science.gov (United States)

    Diop, Babacar; Bonnet, Jean; Schmid, Thomas; Mohamed, Ajmal

    2011-01-01

    We present a new compact electron gun based on the secondary emission through ionic bombardment principle. The driving parameters to develop such a gun are to obtain a quite small electron gun for an in-flight instrument performing Electron Beam Fluorescence measurements (EBF) on board of a reentry vehicle in the upper atmosphere. These measurements are useful to characterize the gas flow around the vehicle in terms of gas chemical composition, temperatures and velocity of the flow which usually presents thermo-chemical non-equilibrium. Such an instrument can also be employed to characterize the upper atmosphere if placed on another carrier like a balloon. In ground facilities, it appears as a more practical tool to characterize flows in wind tunnel studies or as an alternative to complex electron guns in industrial processes requiring an electron beam. We describe in this paper the gun which has been developed as well as its different features which have been characterized in the laboratory.

  12. Microfabrication procedure of PDMS microbeam array using photolithography for laminin printing and piconewton force transduction on axons.

    Science.gov (United States)

    Sasoglu, F Mert; Bohl, Andrew J; Layton, Bradley E

    2006-01-01

    The purpose of this paper is to introduce our design for transducing forces on the order of tens of piconewtons by optically measuring deflection of a microfabricated beam tip as it pulls on an array of flexible structures such as axons in an array of laminin-printed neurons. To achieve this we have designed polymeric beams with spring constants on the order of 10 pN/microm. We have fabricated circular microbeams with Sylgard polydimethylsiloxane (PDMS). The elastic modulus of PDMS was determined experimentally using a microscale and a micrometer at different concentrations of curing agent and base agent and found to be on the order of 100 kPa. The designed geometry is a 100x100 tapered microcone array with each beam having a length of 100 microm, and a base diameter of 10 microm. A SU-8 negative photoresist is etched using photolithography and used as a mold for PDMS soft lithography. PDMS was injected into the mold and the array peeled from the mold.

  13. RFID-based Electronic Identity Security Cloud Platform in Cyberspace

    OpenAIRE

    Bing Chen; Chengxiang Tan; Bo Jin; Xiang Zou; Yuebo Dai

    2012-01-01

    With the moving development of networks, especially Internet of Things, electronic identity administration in cyberspace is becoming more and more important. And personal identity management in cyberspace associated with individuals in reality has been one significant and urgent task for the further development of information construction in China. So this paper presents a RFID-based electronic identity security cloud platform in cyberspace to implement an efficient security management of cyb...

  14. Graphene Electronic Device Based Biosensors and Chemical Sensors

    OpenAIRE

    Jiang, Shan

    2014-01-01

    Two-dimensional layered materials, such as graphene and MoS2, are emerging as an exciting material system for a new generation of atomically thin electronic devices. With their ultrahigh surface to volume ratio and excellent electrical properties, 2D-layered materials hold the promise for the construction of a generation of chemical and biological sensors with unprecedented sensitivity. In my PhD thesis, I mainly focus on graphene based electronic biosensors and chemical sensors. In the first...

  15. Secure electronic commerce communication system based on CA

    Science.gov (United States)

    Chen, Deyun; Zhang, Junfeng; Pei, Shujun

    2001-07-01

    In this paper, we introduce the situation of electronic commercial security, then we analyze the working process and security for SSL protocol. At last, we propose a secure electronic commerce communication system based on CA. The system provide secure services such as encryption, integer, peer authentication and non-repudiation for application layer communication software of browser clients' and web server. The system can implement automatic allocation and united management of key through setting up the CA in the network.

  16. COMPUTER OF TESTING ON DISCIPLINE "BASES ELECTRICAL ENGINEERS AND ELECTRONICS"

    OpenAIRE

    Zarzhetskaja, N.; Noskov, M.

    2010-01-01

    In the given work application of program Electronics Workbench for teaching a rate is described: « Bases electrical engineers and electronics ». It is offered to use the program for carrying out of laboratory works and testing's of quality of knowledge of students. This approach raises quality of mastering of material students. It is the tool for independent check of results. Use of the program fixes the basic skills of calculations of electric circuits. In work the block from six laboratory ...

  17. Microbeam radiation therapy. Physical and biological aspects of a new cancer therapy and development of a treatment planning system

    Energy Technology Data Exchange (ETDEWEB)

    Bartzsch, Stefan

    2014-11-05

    Microbeam Radiation Therapy (MRT) is a novel treatment strategy against cancer. Highly brilliant synchrotron radiation is collimated to parallel, a few micrometre wide, planar beams and used to irradiate malignant tissues with high doses. The applied peak doses are considerably higher than in conventional radiotherapy, but valley doses between the beams remain underneath the established tissue tolerance. Previous research has shown that these beam geometries spare normal tissue, while being effective in tumour ablation. In this work physical and biological aspects of the therapy were investigated. A therapy planning system was developed for the first clinical treatments at the European Synchrotron Radiation Facility in Grenoble (France) and a dosimetry method based on radiochromic films was created to validate planned doses with measurements on a micrometre scale. Finally, experiments were carried out on a cellular level in order to correlate the physically planned doses with the biological damage caused in the tissue. The differences between Monte Carlo dose and dosimetry are less than 10% in the valley and 5% in the peak regions. Developed alternative faster dose calculation methods deviate from the computational intensive MC simulations by less than 15% and are able to determine the dose within a few minutes. The experiments in cell biology revealed an significant influence of intercellular signalling on the survival of cells close to radiation boundaries. These observations may not only be important for MRT but also for conventional radiotherapy.

  18. Ground Base Skylab Electron Beam Welds in Tantalum

    Science.gov (United States)

    2004-01-01

    Comparison of ground-based (left) and Skylab (right) electron beam welds in pure tantalum (Ta) (10X magnification). Residual votices left behind in the ground-based sample after the electron beam passed were frozen into the grain structure. These occurred because of the rapid cooling rate at the high temperature. Although the thermal characteristics and electron beam travel speeds were comparable for the skylab sample, the residual vortices were erased in the grain structure. This may have been due to the fact that final grain size of the solidified material was smaller in the Skylab sample compared to the ground-based sample. The Skylab sample was processed in the M512 Materials Processing Facility (MPF) during Skylab SL-2 Mission. Principal Investigator was Richard Poorman.

  19. Electronic Forms-Based Computing for Evidentiary Analysis

    Directory of Open Access Journals (Sweden)

    Andy Luse

    2009-09-01

    Full Text Available The paperwork associated with evidentiary collection and analysis is a highly repetitive and time-consuming process which often involves duplication of work and can frequently result in documentary errors. Electronic entry of evidencerelated information can facilitate greater accuracy and less time spent on data entry. This manuscript describes a general framework for the implementation of an electronic tablet-based system for evidentiary processing. This framework is then utilized in the design and implementation of an electronic tablet-based evidentiary input prototype system developed for use by forensic laboratories which serves as a verification of the proposed framework. The manuscript concludes with a discussion of implications and recommendations for the implementation and use of tablet-based computing for evidence analysis.

  20. Semiconductor-based, large-area, flexible, electronic devices

    Science.gov (United States)

    Goyal, Amit

    2011-03-15

    Novel articles and methods to fabricate the same resulting in flexible, large-area, triaxially textured, single-crystal or single-crystal-like, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

  1. Ab initio electronic and optical spectra of free-base porphyrins: The role of electronic correlation.

    Science.gov (United States)

    Palummo, Maurizia; Hogan, Conor; Sottile, Francesco; Bagalá, Paolo; Rubio, Angel

    2009-08-28

    We present a theoretical investigation of electronic and optical properties of free-base porphyrins based on density functional theory and many-body perturbation theory. The electronic levels of free-base porphine (H(2)P) and its phenyl derivative, free-base tetraphenylporphyrin (H(2)TPP) are calculated using the ab initio GW approximation for the self-energy. The approach is found to yield results that compare favorably with the available photoemission spectra. The excitonic nature of the optical peaks is revealed by solving the Bethe-Salpeter equation, which provides an accurate description of the experimental absorption spectra. The lowest triplet transition energies are in good agreement with the measured values. PMID:19725603

  2. High resolution X-ray fluorescence imaging for a microbeam radiation therapy treatment planning system

    Science.gov (United States)

    Chtcheprov, Pavel; Inscoe, Christina; Burk, Laurel; Ger, Rachel; Yuan, Hong; Lu, Jianping; Chang, Sha; Zhou, Otto

    2014-03-01

    Microbeam radiation therapy (MRT) uses an array of high-dose, narrow (~100 μm) beams separated by a fraction of a millimeter to treat various radio-resistant, deep-seated tumors. MRT has been shown to spare normal tissue up to 1000 Gy of entrance dose while still being highly tumoricidal. Current methods of tumor localization for our MRT treatments require MRI and X-ray imaging with subject motion and image registration that contribute to the measurement error. The purpose of this study is to develop a novel form of imaging to quickly and accurately assist in high resolution target positioning for MRT treatments using X-ray fluorescence (XRF). The key to this method is using the microbeam to both treat and image. High Z contrast media is injected into the phantom or blood pool of the subject prior to imaging. Using a collimated spectrum analyzer, the region of interest is scanned through the MRT beam and the fluorescence signal is recorded for each slice. The signal can be processed to show vascular differences in the tissue and isolate tumor regions. Using the radiation therapy source as the imaging source, repositioning and registration errors are eliminated. A phantom study showed that a spatial resolution of a fraction of microbeam width can be achieved by precision translation of the mouse stage. Preliminary results from an animal study showed accurate iodine profusion, confirmed by CT. The proposed image guidance method, using XRF to locate and ablate tumors, can be used as a fast and accurate MRT treatment planning system.

  3. Practical Research of Electronic Transformer Based on Interpolation Algorithm

    Directory of Open Access Journals (Sweden)

    Fu Yang

    2013-02-01

    Full Text Available As a result of the adoption of new photovoltaic technology, electronic transformers have great advantages compared with traditional electromagnetic type, such as anti-saturated, high linearity, compact and lightweight etc. The working principle of sensing head of electronic current/voltage transformers is introduced in the paper. The causes of phase error in electronic transformer are analyzed. And a set of phase compensation methods based on the signal transfer principle of electronic transformer is presented. The phase-difference caused by Rogowski coil and time-delay in signal transferring from high voltage side to merging unit are analyzed, and the higher sampling rate and the method of linear interpolation is used to solve the problem. In the simulation test the phase error compensation effect is very good, and the simulation result shows that the integrated error after compensation is able to meet the requirements of the measurement and protection, and demonstrates the validity of the method.

  4. Laser microbeam irradiation and renucleation of mouse eggs. Final progress report, July 1, 1979-December 31, 1983

    International Nuclear Information System (INIS)

    We have combined laser microbeam irradiation of mouse egg nuclei with fusion to donor cell nuclei in order to develop a new procedure for transferring nuclei into mammalian eggs. We have been using virus-treated cells injected into the perivitelline for fusion with egg cells. Binucleate cells inside the zona pellucida were often produced indicating nuclear transfer between cells had occurred. To prevent the formation of such abortive polyploidy, host nuclei were inactivated with a laser microbeam. The subsequent cleavage of the microirradiated eggs has been studied

  5. Electronic Biosensors Based on III-Nitride Semiconductors.

    Science.gov (United States)

    Kirste, Ronny; Rohrbaugh, Nathaniel; Bryan, Isaac; Bryan, Zachary; Collazo, Ramon; Ivanisevic, Albena

    2015-01-01

    We review recent advances of AlGaN/GaN high-electron-mobility transistor (HEMT)-based electronic biosensors. We discuss properties and fabrication of III-nitride-based biosensors. Because of their superior biocompatibility and aqueous stability, GaN-based devices are ready to be implemented as next-generation biosensors. We review surface properties, cleaning, and passivation as well as different pathways toward functionalization, and critically analyze III-nitride-based biosensors demonstrated in the literature, including those detecting DNA, bacteria, cancer antibodies, and toxins. We also discuss the high potential of these biosensors for monitoring living cardiac, fibroblast, and nerve cells. Finally, we report on current developments of covalent chemical functionalization of III-nitride devices. Our review concludes with a short outlook on future challenges and projected implementation directions of GaN-based HEMT biosensors.

  6. 48-Channel electron detector for photoemission spectroscopy and microscopy

    Science.gov (United States)

    Gregoratti, L.; Barinov, A.; Benfatto, E.; Cautero, G.; Fava, C.; Lacovig, P.; Lonza, D.; Kiskinova, M.; Tommasini, R.; Mähl, S.; Heichler, W.

    2004-01-01

    We show that it is possible to use a multichannel electron detector in a zone plate based photoemission spectromicroscopy in a snap shot mode to reduce the total acquisition time for a given counting time by 50% relative to the standard scanning mode while preserving the feature of the spectra. We describe the result of tests performed at Elettra using its microbeam (150 nm) together with a 48-channel detector designed for the PHOIBOS 100 analyzer optimized for extremely small x-ray sources. We also give a short summary of the technical features of the detector and describe one possible calibration procedure for its use in the snap shot mode. We show initial results from using this device to perform chemical maps of surfaces at a resolution of 150 nm.

  7. Vibrations of micro-beams actuated by an electric field via Parameter Expansion Method

    Science.gov (United States)

    Sedighi, Hamid M.; Shirazi, Kourosh H.

    2013-04-01

    This paper presents a new asymptotic procedure to predict the nonlinear vibrational behavior of micro-beams pre-deformed by an electric field. The nonlinear equation of motion includes both even and odd nonlinearities. A powerful analytical method called Parameter Expansion Method (PEM) is employed to obtain the approximated solution and frequency-amplitude relationship. It is demonstrated that the first two terms in series expansions are sufficient to produce an acceptable solution of mentioned system. The obtained results from numerical methods verify the soundness of the analytical procedure. Finally, the influences of basic parameters on pull-in instability and natural frequency are investigated.

  8. An evaluation of dose equivalence between synchrotron microbeam radiation therapy and conventional broad beam radiation using clonogenic and cell impedance assays.

    Directory of Open Access Journals (Sweden)

    Mohammad Johari Ibahim

    Full Text Available BACKGROUND: High-dose synchrotron microbeam radiation therapy (MRT has shown the potential to deliver improved outcomes over conventional broadbeam (BB radiation therapy. To implement synchrotron MRT clinically for cancer treatment, it is necessary to undertake dose equivalence studies to identify MRT doses that give similar outcomes to BB treatments. AIM: To develop an in vitro approach to determine biological dose equivalence between MRT and BB using two different cell-based assays. METHODS: The acute response of tumour and normal cell lines (EMT6.5, 4T1.2, NMuMG, EMT6.5ch, 4T1ch5, SaOS-2 to MRT (50-560 Gy and BB (1.5-10 Gy irradiation was investigated using clonogenic and real time cell impedance sensing (RT-CIS/xCELLigence assays. MRT was performed using a lattice of 25 or 50 µm-wide planar, polychromatic kilovoltage X-ray microbeams with 200 µm peak separation. BB irradiations were performed using a Co60 teletherapy unit or a synchrotron radiation source. BB doses that would generate biological responses similar to MRT were calculated by data interpolation and verified by clonogenic and RT-CIS assays. RESULTS: For a given cell line, MRT equivalent BB doses identified by RT-CIS/xCELLigence were similar to those identified by clonogenic assays. Dose equivalence between MRT and BB were verified in vitro in two cell lines; EMT6.5ch and SaOS-2 by clonogenic assays and RT-CIS/xCELLigence. We found for example, that BB doses of 3.4±0.1 Gy and 4.40±0.04 Gy were radiobiologically equivalent to a peak, microbeam dose of 112 Gy using clonogenic and RT-CIS assays respectively on EMT6.5ch cells. CONCLUSION: Our data provides the first determination of biological dose equivalence between BB and MRT modalities for different cell lines and identifies RT-CIS/xCELLigence assays as a suitable substitute for clonogenic assays. These results will be useful for the safe selection of MRT doses for future veterinary and clinical trials.

  9. Gap Junction Communication and the Propagation of Bystander Effects Induced by Microbeam Irradiation in Human Fibroblast Cultures: The Impact of Radiation Quality

    Science.gov (United States)

    Autsavapromporn, Narongchai; Suzuki, Masao; Funayama, Tomoo; Usami, Noriko; Plante, Ianik; Yokota, Yuichiro; Mutou, Yasuko; Ikeda, Hiroko; Kobayashi, Katsumi; Kobayashi, Yasuhiko; Uchihori, Yukio; Hei, Tom K.; Azzam, Edouard I.; Murakami, Takeshi

    2014-01-01

    Understanding the mechanisms underlying the bystander effects of low doses/low fluences of low- or high-linear energy transfer (LET) radiation is relevant to radiotherapy and radiation protection. Here, we investigated the role of gap-junction intercellular communication (GJIC) in the propagation of stressful effects in confluent normal human fibroblast cultures wherein only 0.036–0.144% of cells in the population were traversed by primary radiation tracks. Confluent cells were exposed to graded doses from monochromatic 5.35 keV X ray (LET ~6 keV/μm), 18.3 MeV/u carbon ion (LET ~103 keV/μm), 13 MeV/u neon ion (LET ~380 keV/μm) or 11.5 MeV/u argon ion (LET ~1,260 keV/μm) microbeams in the presence or absence of 18-α-glycyrrhetinic acid (AGA), an inhibitor of GJIC. After 4 h incubation at 37°C, the cells were subcultured and assayed for micronucleus (MN) formation. Micronuclei were induced in a greater fraction of cells than expected based on the fraction of cells targeted by primary radiation, and the effect occurred in a dose-dependent manner with any of the radiation sources. Interestingly, MN formation for the heavy-ion microbeam irradiation in the absence of AGA was higher than in its presence at high mean absorbed doses. In contrast, there were no significant differences in cell cultures exposed to X-ray microbeam irradiation in presence or absence of AGA. This showed that the inhibition of GJIC depressed the enhancement of MN formation in bystander cells from cultures exposed to high-LET radiation but not low-LET radiation. Bystander cells recipient of growth medium harvested from 5.35 keV X-irradiated cultures experienced stress manifested in the form of excess micronucleus formation. Together, the results support the involvement of both junctional communication and secreted factor(s) in the propagation of radiation-induced stress to bystander cells. They highlight the important role of radiation quality and dose in the observed effects. PMID:23987132

  10. High-precision radiosurgical dose delivery by interlaced microbeam arrays of high-flux low-energy synchrotron X-rays.

    Directory of Open Access Journals (Sweden)

    Raphaël Serduc

    Full Text Available Microbeam Radiation Therapy (MRT is a preclinical form of radiosurgery dedicated to brain tumor treatment. It uses micrometer-wide synchrotron-generated X-ray beams on the basis of spatial beam fractionation. Due to the radioresistance of normal brain vasculature to MRT, a continuous blood supply can be maintained which would in part explain the surprising tolerance of normal tissues to very high radiation doses (hundreds of Gy. Based on this well described normal tissue sparing effect of microplanar beams, we developed a new irradiation geometry which allows the delivery of a high uniform dose deposition at a given brain target whereas surrounding normal tissues are irradiated by well tolerated parallel microbeams only. Normal rat brains were exposed to 4 focally interlaced arrays of 10 microplanar beams (52 microm wide, spaced 200 microm on-center, 50 to 350 keV in energy range, targeted from 4 different ports, with a peak entrance dose of 200Gy each, to deliver an homogenous dose to a target volume of 7 mm(3 in the caudate nucleus. Magnetic resonance imaging follow-up of rats showed a highly localized increase in blood vessel permeability, starting 1 week after irradiation. Contrast agent diffusion was confined to the target volume and was still observed 1 month after irradiation, along with histopathological changes, including damaged blood vessels. No changes in vessel permeability were detected in the normal brain tissue surrounding the target. The interlacing radiation-induced reduction of spontaneous seizures of epileptic rats illustrated the potential pre-clinical applications of this new irradiation geometry. Finally, Monte Carlo simulations performed on a human-sized head phantom suggested that synchrotron photons can be used for human radiosurgical applications. Our data show that interlaced microbeam irradiation allows a high homogeneous dose deposition in a brain target and leads to a confined tissue necrosis while sparing

  11. Carbon based materials for electronic bio-sensing

    Directory of Open Access Journals (Sweden)

    Maria D. Angione

    2011-09-01

    Full Text Available Bio-sensing represents one of the most attractive applications of carbon material based electronic devices; nevertheless, the complete integration of bioactive transducing elements still represents a major challenge, particularly in terms of preserving biological function and specificity while maintaining the sensor's electronic performance. This review highlights recent advances in the realization of field-effect transistor (FET based sensors that comprise a bio-receptor within the FET channel. A birds-eye view will be provided of the most promising classes of active layers as well as different device architectures and methods of fabrication. Finally, strategies for interfacing bio-components with organic or carbon nano-structured electronic active layers are reported.

  12. Fullerene-based Anchoring Groups for Molecular Electronics

    DEFF Research Database (Denmark)

    Martin, Christian A.; Ding, Dapeng; Sørensen, Jakob Kryger;

    2008-01-01

    We present results on a new fullerene-based anchoring group for molecular electronics. Using lithographic mechanically controllable break junctions in vacuum we have determined the conductance and stability of single-molecule junctions of 1,4-bis(fullero[c]pyrrolidin-1-yl)benzene. The compound can...

  13. Weblog-Based Electronic Portfolios for Student Teachers in Taiwan

    Science.gov (United States)

    Chuang, Hsueh-Hua

    2010-01-01

    This paper explored how the use of weblogs within the portfolio framework affected portfolio production and development for student teachers, and how the weblog-based electronic portfolio (WBEP) shaped student teachers' reflective practice during the student teaching practicum. The individuals participating in this study consisted of 31 elementary…

  14. In plane optical sensor based on organic electronic devices

    NARCIS (Netherlands)

    Koetse, M.M; Rensing, P.A.; Heck, G.T. van; Sharpe, R.B.A.; Allard, B.A.M.; Wieringa, F.P.; Kruijt, P.G.M.; Meulendijks, N.M.M.; Jansen, H.; Schoo, H.F.M.

    2008-01-01

    Sensors based on organic electronic devices are emerging in a wide range of application areas. Here we present a sensor platform using organic light emitting diodes (OLED) and organic photodiodes (OPD) as active components. By means of lamination and interconnection technology the functional foils w

  15. Model Checking Electronic Commerce Security Protocols Based on CTL

    Institute of Scientific and Technical Information of China (English)

    XIAO De-qin; ZHANG Huan-guo

    2005-01-01

    We present a model based on Computational Temporal Logic (CTL) methods for verifying security requirements of electronic commerce protocols. The model describes formally the authentication, confidentiality integrity,non-repudiation, denial of service and access control of the electronic commerce protocols. We illustrate as case study a variant of the Lu-Smolka protocol proposed by Lu-Smolka.Moreover, we have discovered two attacks that allow a dishonest user to purchase a good debiting the amount to another user. And also, we compared our work with relative research works and found that the formal way of this paper is more general to specify security protocols for E-Commerce.

  16. A laser printing based approach for printed electronics

    Science.gov (United States)

    Zhang, T.; Hu, M.; Liu, Y.; Guo, Q.; Wang, X.; Zhang, W.; Lau, W.; Yang, J.

    2016-03-01

    Here we report a study of printing of electronics using an office use laser printer. The proposed method eliminates those critical disadvantages of solvent-based printing techniques by taking the advantages of electroless deposition and laser printing. The synthesized toner acts as a catalyst for the electroless copper deposition as well as an adhesion-promoting buffer layer between the substrate and deposited copper. The easy metallization of printed patterns and strong metal-substrate adhesion make it an especially effective method for massive production of flexible printed circuits. The proposed process is a high throughput, low cost, efficient, and environmentally benign method for flexible electronics manufacturing.

  17. Electronic implementation of associative memory based on neural network models

    Science.gov (United States)

    Moopenn, A.; Lambe, John; Thakoor, A. P.

    1987-01-01

    An electronic embodiment of a neural network based associative memory in the form of a binary connection matrix is described. The nature of false memory errors, their effect on the information storage capacity of binary connection matrix memories, and a novel technique to eliminate such errors with the help of asymmetrical extra connections are discussed. The stability of the matrix memory system incorporating a unique local inhibition scheme is analyzed in terms of local minimization of an energy function. The memory's stability, dynamic behavior, and recall capability are investigated using a 32-'neuron' electronic neural network memory with a 1024-programmable binary connection matrix.

  18. Electronic properties of graphene-based bilayer systems

    Science.gov (United States)

    Rozhkov, A. V.; Sboychakov, A. O.; Rakhmanov, A. L.; Nori, Franco

    2016-08-01

    This article reviews the theoretical and experimental work related to the electronic properties of bilayer graphene systems. Three types of bilayer stackings are discussed: the AA, AB, and twisted bilayer graphene. This review covers single-electron properties, effects of static electric and magnetic fields, bilayer-based mesoscopic systems, spin-orbit coupling, dc transport and optical response, as well as spontaneous symmetry violation and other interaction effects. The selection of the material aims to introduce the reader to the most commonly studied topics of theoretical and experimental research in bilayer graphene.

  19. Paintings on copper by the Flemish artist Frans Francken II: PIXE characterization by external microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Corregidor, V., E-mail: vicky.corregidor@ctn.ist.utl.pt [IPFN, Instituto Superior Técnico, Campus Tecnológico e Nuclear, Universidade de Lisboa, E.N. 10, 2695-066 Sacavém (Portugal); Oliveira, A.R. [CCR-Centro de Conservação e Restauro, R. do Ginjal, 11, 2950-685 Palmela (Portugal); Rodrigues, P.A. [LATR, Instituto Superior Técnico, Campus Tecnológico e Nuclear, Universidade de Lisboa, E.N. 10, 2695-066 Sacavém (Portugal); Alves, L.C. [C2TN, Instituto Superior Técnico, Campus Tecnológico e Nuclear, Universidade de Lisboa, E.N. 10, 2695-066 Sacavém (Portugal)

    2015-04-01

    Resorting to an external proton microbeam, PIXE analyses of three oil paintings on copper support dated from the XVII century and attributed to the Flemish artist Frans Francken II, were undertaken. The present work aims to contribute to the compositional study of the painting materials employed by XVII century artists that exploited copper as a support for oil painting, and specifically the materials used by Francken’s workshop, particularly copper plates. Because of the low thickness of the pictorial layers of this type of paintings and its non-destructive character, PIXE is the ideal technique to study the elemental composition of the paintings. Several spots in each painting were chosen for analysis in order to cover almost all the pigments used in the colour palette. Lead and calcium were detected in practically every analysed regions, probably related to the presence of lead white and chalk, usually used as ground layer on copper paintings. Small quantities of gold were also detected, which is present in many of this artist’s works to embellish some details of the representations. Also this work reports the first application of the external proton microbeam set-up available at CTN/IST in Portugal for the characterization of oil paintings.

  20. Examination of laser microbeam cell lysis in a PDMS microfluidic channel using time-resolved imaging.

    Science.gov (United States)

    Quinto-Su, Pedro A; Lai, Hsuan-Hong; Yoon, Helen H; Sims, Christopher E; Allbritton, Nancy L; Venugopalan, Vasan

    2008-03-01

    We use time-resolved imaging to examine the lysis dynamics of non-adherent BAF-3 cells within a microfluidic channel produced by the delivery of single highly-focused 540 ps duration laser pulses at lambda = 532 nm. Time-resolved bright-field images reveal that the delivery of the pulsed laser microbeam results in the formation of a laser-induced plasma followed by shock wave emission and cavitation bubble formation. The confinement offered by the microfluidic channel constrains substantially the cavitation bubble expansion and results in significant deformation of the PDMS channel walls. To examine the cell lysis and dispersal of the cellular contents, we acquire time-resolved fluorescence images of the process in which the cells were loaded with a fluorescent dye. These fluorescence images reveal cell lysis to occur on the nanosecond to microsecond time scale by the plasma formation and cavitation bubble dynamics. Moreover, the time-resolved fluorescence images show that while the cellular contents are dispersed by the expansion of the laser-induced cavitation bubble, the flow associated with the bubble collapse subsequently re-localizes the cellular contents to a small region. This capacity of pulsed laser microbeam irradiation to achieve rapid cell lysis in microfluidic channels with minimal dilution of the cellular contents has important implications for their use in lab-on-a-chip applications. PMID:18305858

  1. Tumor Cell Response to Synchrotron Microbeam Radiation Therapy Differs Markedly From Cells in Normal Tissues

    International Nuclear Information System (INIS)

    Purpose: High-dose synchrotron microbeam radiation therapy (MRT) can be effective at destroying tumors in animal models while causing very little damage to normal tissues. The aim of this study was to investigate the cellular processes behind this observation of potential clinical importance. Methods and Materials: MRT was performed using a lattice of 25 μm-wide, planar, polychromatic, kilovoltage X-ray microbeams, with 200-μm peak separation. Inoculated EMT-6.5 tumor and normal mouse skin tissues were harvested at defined intervals post-MRT. Immunohistochemical detection of γ-H2AX allowed precise localization of irradiated cells, which were also assessed for proliferation and apoptosis. Results: MRT significantly reduced tumor cell proliferation by 24 h post-irradiation (p = 0.002). An unexpected finding was that within 24 h of MRT, peak and valley irradiated zones were indistinguishable in tumors because of extensive cell migration between the zones. This was not seen in MRT-treated normal skin, which appeared to undergo a coordinated repair response. MRT elicited an increase in median survival times of EMT-6.5 and 67NR tumor-inoculated mice similar to that achieved with conventional radiotherapy, while causing markedly less normal tissue damage. Conclusions: This study provides evidence of a differential response at a cellular level between normal and tumor tissues after synchrotron MRT.

  2. A Microbeam Small-Angle X-ray Scattering Study on Enamel Crystallites in Subsurface Lesion

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, N; Ohta, N; Matsuo, T [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Tanaka, T; Terada, Y; Kamasaka, H; Kometani, T, E-mail: yagi@spring8.or.j [Ezaki Glico Co. Ltd., 4-6-5 Utajima, Nishiyodogawa-ku, Osaka 555-8502 (Japan)

    2010-10-01

    The early caries lesion in bovine tooth enamel was studied by two different X-ray diffraction systems at the SPring-8 third generation synchrotron radiation facility. Both allowed us simultaneous measurement of the small and large angle regions. The beam size was 6{mu}m at BL40XU and 50{mu}m at BL45XU. The small-angle scattering from voids in the hydroxyapatite crystallites and the wide-angle diffraction from the hydroxyapatite crystals were observed simultaneously. At BL40XU an X-ray image intensifier was used for the small-angle and a CMOS flatpanel detector for the large-angle region. At BL45XU, a large-area CCD detector was used to cover both regions. A linear microbeam scan at BL40XU showed a detailed distribution of voids and crystals and made it possible to examine the structural details in the lesion. The two-dimensional scan at BL45XU showed distribution of voids and crystals in a wider region in the enamel. The simultaneous small- and wide-angle measurement with a microbeam is a powerful tool to elucidate the mechanisms of demineralization and remineralization in the early caries lesion.

  3. A count rate based contamination control standard for electron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    May, R.T.; Schwahn, S.O.

    1996-12-31

    Accelerators of sufficient energy and particle fluence can produce radioactivity as an unwanted byproduct. The radioactivity is typically imbedded in structural materials but may also be removable from surfaces. Many of these radionuclides decay by positron emission or electron capture; they often have long half lives and produce photons of low energy and yield making detection by standard devices difficult. The contamination control limit used throughout the US nuclear industry and the Department of Energy is 1,000 disintegrations per minute. This limit is based on the detection threshold of pancake type Geiger-Mueller probes for radionuclides of relatively high radiotoxicity, such as cobalt-60. Several radionuclides of concern at a high energy electron accelerator are compared in terms of radiotoxicity with radionuclides commonly found in the nuclear industry. Based on this comparison, a count-rate based contamination control limit and associated measurement strategy is proposed which provides adequate detection of contamination at accelerators without an increase in risk.

  4. Portable audio electronics for impedance-based measurements in microfluidics

    International Nuclear Information System (INIS)

    We demonstrate the use of audio electronics-based signals to perform on-chip electrochemical measurements. Cell phones and portable music players are examples of consumer electronics that are easily operated and are ubiquitous worldwide. Audio output (play) and input (record) signals are voltage based and contain frequency and amplitude information. A cell phone, laptop soundcard and two compact audio players are compared with respect to frequency response; the laptop soundcard provides the most uniform frequency response, while the cell phone performance is found to be insufficient. The audio signals in the common portable music players and laptop soundcard operate in the range of 20 Hz to 20 kHz and are found to be applicable, as voltage input and output signals, to impedance-based electrochemical measurements in microfluidic systems. Validated impedance-based measurements of concentration (0.1–50 mM), flow rate (2–120 µL min−1) and particle detection (32 µm diameter) are demonstrated. The prevailing, lossless, wave audio file format is found to be suitable for data transmission to and from external sources, such as a centralized lab, and the cost of all hardware (in addition to audio devices) is ∼10 USD. The utility demonstrated here, in combination with the ubiquitous nature of portable audio electronics, presents new opportunities for impedance-based measurements in portable microfluidic systems. (technical note)

  5. Thermionic field electron emission from graphite-based nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Lyashenko, S.; Kleshch, V. [Department of Physics, Moscow State University, Moscow (Russian Federation); Obraztsov, A. [Department of Physics, Moscow State University, Moscow (Russian Federation); Department of Physics and Mathematics, University of Eastern Finland, Joensuu (Finland)

    2011-11-15

    Thermionic and field electron emissions governed by Richardson-Dushman and Fowler-Nordheim equations, respectively, normally coexist under typical experimental conditions. However, some carbon-based cathodes demonstrate deviations of temperature dependencies of the current-voltage characteristics from those predicted by these equations. The nature of deviations cannot be ascribed to insufficient variations of work function or surface topology, which result from temperature variations. In this work, the temperature dependencies of the electron emission characteristics were experimentally investigated for the nanographite film cathodes obtained by a chemical vapor deposition method. It was found that self-consistent explanation of the experimental observations of the thermionic and field electron emissions from the nanocarbon cathodes may be given by taking into account the temperature dependence of free carrier density. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. ERL Based Electron-Ion Collider eRHIC

    CERN Document Server

    Litvinenko, Vladimir N; Bai, Mei; Beebe-Wang, Joanne; Ben-Zvi, Ilan; Blaskiewicz, Michael; Brennan, Joseph M; Calaga, Rama; Chang, Xiangyun; Deshpande, Abhay A; Farkhondeh, Manouchehr; Fedotov, Alexei V; Fischer, Wolfram; Kayran, Dmitry; Kewisch, Jorg; MacKay, William W; Montag, Christoph; Parker, Brett; Peggs, Steve; Ptitsyn, Vadim; Roser, Thomas; Ruggiero, Alessandro; Satogata, Todd; Surrow, Bernd; Tepikian, Steven; Trbojevic, Dejan; Yakimenko, Vitaly; Zhang, S Y

    2005-01-01

    We present the designs of a future polarized electron-hadron collider, eRHIC* based on a high current super-conducting energy-recovery linac (ERL) with energy of electrons up to 20 GeV. We plan to operate eRHIC in both dedicated (electron-hadrons only) and parallel(with the main hadron-hadron collisions) modes. The eRHIC has very large tunability range of c.m. energies while maintaining very high luminosity up to 1034 cm-2 s-1 per nucleon. Two of the most attractive features of this scheme are full spin transparency of the ERL at all operational energies and the capability to support up to four interaction points. We present two main layouts of the eRHIC, the expected beam and luminosity parameter, and discuss the potential limitation of its performance.

  7. Electron injection and transport mechanism in organic devices based on electron transport materials

    Energy Technology Data Exchange (ETDEWEB)

    Khan, M A; Xu Wei; Khizar-ul-Haq; Zhang Xiaowen; Bai Yu; Jiang, X Y; Zhang, Z L; Zhu, W Q [Department of Materials Science, Shanghai University, Jiading 201800 (China)

    2008-11-21

    Electron injection and transport in organic devices based on electron transport (ET) materials, such as 4,7- diphyenyl-1,10-phenanthroline (Bathophenanthroline BPhen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (Bathocuproine BCP) and bipyridyl oxadiazole compound 1,3-bis [2-(2,2'-bipyridin-6-yl)-1,3,4-oxadiazol-5-yl]benzene (Bpy-OXD), have been reported. The devices are composed of ITO/ET materials (BPhen, BCP Bpy-OXD)/cathodes, where cathodes = Au, Al and Ca. Current-voltage characteristics of each ET material are performed as a function of cathodes. We have found that Ca and Al exhibit quite different J-V characteristics compared with the gold (Au) cathode. The current is more than one order of magnitude higher for the Al cathode and more than three orders of magnitude higher for Ca compared with that of the Au cathode at {approx}8 V for all ET materials. This is because of the relatively low energy barrier at the organic/metal interface for Ca and Al cathodes. Electron-only devices with the Au cathode show that the electron transfer limitation is located at the organic/cathode interface and the Fowler-Nordheim mechanism is qualitatively consistent with experimental data at high voltages. With Ca and Al cathodes, electron conduction is preponderant and is bulk limited. A power law dependence J {approx} V{sup m} with m > 2 is consistent with the model of trap-charge limited conduction. The total electron trap density is estimated to be {approx}5 x 10{sup 18} cm{sup -3}. The critical voltage (V{sub c}) is found to be {approx}45 V and is almost independent of the materials.

  8. Studying nanostructure gradients in injection-molded polypropylene/montmorillonite composites by microbeam small-angle x-ray scattering

    DEFF Research Database (Denmark)

    Stribeck, Norbert; Schneider, Konrad; Zeinolebadi, Ahmad;

    2014-01-01

    The core–shell structure in oriented cylindrical rods of polypropylene (PP) and nanoclay composites (NCs) from PP and montmorillonite (MMT) is studied by microbeam small-angle x-ray scattering (SAXS). The structure of neat PP is almost homogeneous across the rod showing regular semicrystalline st...

  9. Electronic image stabilization system based on global feature tracking

    Institute of Scientific and Technical Information of China (English)

    Zhu Juanjuan; Guo Baolong

    2008-01-01

    A new robust electronic image stabilization system is presented, which involves feature-point, tracking based global motion estimation and Kalman filtering based motion compensation. First, global motion is estimated from the local motions of selected feature points. Considering the local moving objects or the inevitable mismatch,the matching validation, based on the stable relative distance between the points set is proposed, thus maintaining high accuracy and robustness. Next, the global motion parameters are accumulated for correction by Kalman filter-ation. The experimental result illustrates that the proposed system is effective to stabilize translational, rotational,and zooming jitter and robust to local motions.

  10. Atom location using scanning transmission electron microscopy based on electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Full text: The technique of atom location by channelling enhanced microanalysis (ALCHEMI) using cross section data, measured as a function of electron beam orientation, has been widely implemented by many researchers. The accurate application of ALCHEMI, usually based on energy dispersive x-ray analysis (EDX), requires knowledge, from first principles, of the relative delocalization of the inner-shell ionization interaction (see for example Oxley and Allen, 1998; Oxley et al., 1999). Scanning transmission electron microscopy (STEM) based on electron energy loss spectroscopy (EELS) also provides information about the location of atoms of different types within the crystal lattice. Unlike high angle annular dark field (HAADF), EELS provides a unique signal for each atom type. In conjunction with highly focused probes, allowing near atomic resolution, this makes possible, in principle, the application of ALCHEMI like techniques to STEM images to determine the distribution of impurities within the unit cell. The accurate interpretation of STEM results requires that both the inner-shell ionization interaction and resulting ionization cross section or image be correctly modelled. We present model calculations demonstrating the in principle application of ALCHEMI type techniques to STEM images pertinent to EELS. The inner-shell ionisation interaction is modelled using Hartree-Fock wave functions to describe the atomic bound states and Hartree-Slater wave functions to describe the continuum states. The wave function within the crystal is calculated using boundary conditions appropriate for a highly focussed probe (Rossouw and Allen, 2001) and STEM images or ionisation cross sections are simulated using an inelastic cross section formulation that correctly accounts for the contribution from both dynamical electrons and those dechannelled by absorptive scattering processes such as thermal diffuse scattering (TDS). Copyright (2002) Australian Society for Electron Microscopy

  11. Electron-doping of graphene-based devices by hydrazine

    International Nuclear Information System (INIS)

    A facile and effective technique to tune the electronic properties of graphene is essential to facilitate the flexibility of graphene-based device performances. Here, the use of hydrazine as a solution-processable and effective n-type dopant for graphene is described. By dropping hydrazine solutions at different concentrations on a graphene surface, the Dirac point of graphene can be remarkably tuned. The transport behavior of graphene can be changed from p-type to n-type accordingly, demonstrating the controllable and adjustable doping effect of the hydrazine solutions. Accompanying the Dirac point shift is an enhanced hysteretic behavior of the graphene conductance, indicating an increasing trap state density induced by the hydrazine adsorbates. The electron-doping of graphene by the hydrazine solutions can be additionally confirmed with graphene/p-type silicon heterojunctions. The decrease of the junction current after the hydrazine treatment demonstrates an increase of the junction barrier between graphene and silicon, which is essentially due to the electron-doping of graphene and the resultant upshift of the Fermi level. Finally, partially doped graphene is realized and its electrical property is studied to demonstrate the potential of the hydrazine solutions to selectively electron-doping graphene for future electronic applications

  12. Recent advances in molecular electronics based on carbon nanotubes.

    Science.gov (United States)

    Bourgoin, Jean-Philippe; Campidelli, Stéphane; Chenevier, Pascale; Derycke, Vincent; Filoramo, Arianna; Goffman, Marcelo F

    2010-01-01

    Carbon nanotubes (CNTs) have exceptional physical properties that make them one of the most promising building blocks for future nanotechnologies. They may in particular play an important role in the development of innovative electronic devices in the fields of flexible electronics, ultra-high sensitivity sensors, high frequency electronics, opto-electronics, energy sources and nano-electromechanical systems (NEMS). Proofs of concept of several high performance devices already exist, usually at the single device level, but there remain many serious scientific issues to be solved before the viability of such routes can be evaluated. In particular, the main concern regards the controlled synthesis and positioning of nanotubes. In our opinion, truly innovative use of these nano-objects will come from: (i) the combination of some of their complementary physical properties, such as combining their electrical and mechanical properties, (ii) the combination of their properties with additional benefits coming from other molecules grafted on the nanotubes, and (iii) the use of chemically- or bio-directed self-assembly processes to allow the efficient combination of several devices into functional arrays or circuits. In this article, we outline the main issues concerning the development of carbon nanotubes based electronics applications and review our recent results in the field.

  13. Electron tomography based on a total variation minimization reconstruction technique

    Energy Technology Data Exchange (ETDEWEB)

    Goris, B., E-mail: bart.goris@ua.ac.be [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Van den Broek, W. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Batenburg, K.J. [Centrum Wiskunde and Informatica, Science Park 123, NL-1098XG Amsterdam (Netherlands); Vision Lab, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Belgium); Heidari Mezerji, H.; Bals, S. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2012-02-15

    The 3D reconstruction of a tilt series for electron tomography is mostly carried out using the weighted backprojection (WBP) algorithm or using one of the iterative algorithms such as the simultaneous iterative reconstruction technique (SIRT). However, it is known that these reconstruction algorithms cannot compensate for the missing wedge. Here, we apply a new reconstruction algorithm for electron tomography, which is based on compressive sensing. This is a field in image processing specialized in finding a sparse solution or a solution with a sparse gradient to a set of ill-posed linear equations. Therefore, it can be applied to electron tomography where the reconstructed objects often have a sparse gradient at the nanoscale. Using a combination of different simulated and experimental datasets, it is shown that missing wedge artefacts are reduced in the final reconstruction. Moreover, it seems that the reconstructed datasets have a higher fidelity and are easier to segment in comparison to reconstructions obtained by more conventional iterative algorithms. -- Highlights: Black-Right-Pointing-Pointer A reconstruction algorithm for electron tomography is investigated based on total variation minimization. Black-Right-Pointing-Pointer Missing wedge artefacts are reduced by this algorithm. Black-Right-Pointing-Pointer The reconstruction is easier to segment. Black-Right-Pointing-Pointer More reliable quantitative information can be obtained.

  14. Implementing Electronic Tablet-Based Education of Acute Care Patients.

    Science.gov (United States)

    Sawyer, Tenita; Nelson, Monica J; McKee, Vickie; Bowers, Margaret T; Meggitt, Corilin; Baxt, Sarah K; Washington, Delphine; Saladino, Louise; Lehman, E Philip; Brewer, Cheryl; Locke, Susan C; Abernethy, Amy; Gilliss, Catherine L; Granger, Bradi B

    2016-02-01

    Poor education-related discharge preparedness for patients with heart failure is believed to be a major cause of avoidable rehospitalizations. Technology-based applications offer innovative educational approaches that may improve educational readiness for patients in both inpatient and outpatient settings; however, a number of challenges exist when implementing electronic devices in the clinical setting. Implementation challenges include processes for "on-boarding" staff, mediating risks of cross-contamination with patients' device use, and selling the value to staff and health system leaders to secure the investment in software, hardware, and system support infrastructure. Strategies to address these challenges are poorly described in the literature. The purpose of this article is to present a staff development program designed to overcome challenges in implementing an electronic, tablet-based education program for patients with heart failure. PMID:26830181

  15. Electronic Voting Protocol Using Identity-Based Cryptography

    Science.gov (United States)

    Gallegos-Garcia, Gina; Tapia-Recillas, Horacio

    2015-01-01

    Electronic voting protocols proposed to date meet their properties based on Public Key Cryptography (PKC), which offers high flexibility through key agreement protocols and authentication mechanisms. However, when PKC is used, it is necessary to implement Certification Authority (CA) to provide certificates which bind public keys to entities and enable verification of such public key bindings. Consequently, the components of the protocol increase notably. An alternative is to use Identity-Based Encryption (IBE). With this kind of cryptography, it is possible to have all the benefits offered by PKC, without neither the need of certificates nor all the core components of a Public Key Infrastructure (PKI). Considering the aforementioned, in this paper we propose an electronic voting protocol, which meets the privacy and robustness properties by using bilinear maps. PMID:26090515

  16. Electronic Voting Protocol Using Identity-Based Cryptography.

    Science.gov (United States)

    Gallegos-Garcia, Gina; Tapia-Recillas, Horacio

    2015-01-01

    Electronic voting protocols proposed to date meet their properties based on Public Key Cryptography (PKC), which offers high flexibility through key agreement protocols and authentication mechanisms. However, when PKC is used, it is necessary to implement Certification Authority (CA) to provide certificates which bind public keys to entities and enable verification of such public key bindings. Consequently, the components of the protocol increase notably. An alternative is to use Identity-Based Encryption (IBE). With this kind of cryptography, it is possible to have all the benefits offered by PKC, without neither the need of certificates nor all the core components of a Public Key Infrastructure (PKI). Considering the aforementioned, in this paper we propose an electronic voting protocol, which meets the privacy and robustness properties by using bilinear maps.

  17. DNA damage on nano- and micrometer scales impacts dicentric induction: computer modelling of ion microbeam experiments

    Science.gov (United States)

    Friedland, Werner; Kundrat, Pavel; Schmitt, Elke

    2016-07-01

    Detailed understanding of the enhanced relative biological effectiveness (RBE) of ions, in particular at high linear energy transfer (LET) values, is needed to fully explore the radiation risk of manned space missions. It is generally accepted that the enhanced RBE of high-LET particles results from the DNA lesion patterns, in particular DNA double-strand breaks (DSB), due to the spatial clustering of energy deposits around their trajectories. In conventional experiments on biological effects of radiation types of diverse quality, however, clustering of energy deposition events on nanometer scale that is relevant for the induction and local complexity of DSB is inherently interlinked with regional (sub-)micrometer-scale DSB clustering along the particle tracks. Due to this limitation, the role of both (nano- and micrometer) scales on the induction of diverse biological endpoints cannot be frankly separated. To address this issue in a unique way, experiments at the ion microbeam SNAKE [1] and corresponding track-structure based model calculations of DSB induction and subsequent repair with the biophysical code PARTRAC [2] have been performed. In the experiments, hybrid human-hamster A_{L} cells were irradiated with 20 MeV (2.6 keV/μm) protons, 45 MeV (60 keV/μm) lithium ions or 55 MeV (310 keV/μm) carbon ions. The ions were either quasi-homogeneously distributed or focused to 0.5 x 1 μm^{2} spots on regular matrix patterns of 5.4 μm, 7.6 μm and 10.6 μm grid size, with pre-defined particle numbers per spot so as to deposit a mean dose of 1.7 Gy for all irradiation patterns. As expected, the induction of dicentrics by homogeneous irradiation increased with LET: lithium and carbon ions induced about two- and four-fold higher yields of dicentrics than protons. The induction of dicentrics is, however, affected by µm-scale, too: focusing 20 lithium ions or 451 protons per spot on a 10.6 μm grid induced two or three times more dicentrics, respectively, than a

  18. Weanling piglet cerebellum: a surrogate for tolerance to MRT (microbeam radiation therapy) in pediatric neuro-oncology

    Science.gov (United States)

    Laissue, Jean A.; Blattmann, Hans; Di Michiel, Marco; Slatkin, Daniel N.; Lyubimova, Nadia; Guzman, Raphael; Zimmermann, Werner; Birrer, Stephan; Bley, Tim; Kircher, Patrick; Stettler, Regina; Fatzer, Rosmarie; Jaggy, Andre; Smilowitz, Henry; Brauer, Elke; Bravin, Alberto; Le Duc, Geraldine; Nemoz, Christian; Renier, Michel; Thomlinson, William C.; Stepanek, Jiri; Wagner, Hans-Peter

    2001-12-01

    The cerebellum of the weanling piglet (Yorkshire) was used as a surrogate for the radiosensitive human infant cerebellum in a Swiss-led program of experimental microbeam radiation therapy (MRT) at the ESRF. Five weanlings in a 47 day old litter of seven, and eight weanlings in a 40 day old litter of eleven were irradiated in November, 1999 and June, 2000, respectively. A 1.5 cm-wide x 1.5 xm-high array of equally space approximately equals 20-30 micrometers wide, upright microbeams spaced at 210 micrometers intervals was propagated horizontally, left to right, through the cerebella of the prone, anesthetized piglets. Skin-entrance intra-microbeam peak adsorbed doses were uniform, either 150, 300, 425, or 600 gray (Gy). Peak and inter-microbeam (valley) absorbed doses in the cerebellum were computed with the PSI version of the Monte Carlo code GEANT and benchmarked using Gafchromic and radiochromic film microdosimetry. For approximately equals 66 weeks [first litter; until euthanasia], or approximately equals 57 weeks [second litter; until July 30, 2001] after irradiation, the littermates were developmentally, behaviorally, neurologically and radiologically normal as observed and tested by experienced farmers and veterinary scientists unaware of which piglets were irradiated or sham-irradiated. Morever, MRT implemented at the ESRF with a similar array of microbeams and a uniform skin-entrance peak dose of 625 Gy, followed by immunoprophylaxis, was shown to be palliative or curative in young adult rats bearing intracerebral gliosarcomas. These observations give further credence to MRT's potential as an adjunct therapy for brain tumors in infancy, when seamless therapeutic irradiation of the brain is hazardous.

  19. Electronic structure of ternary hydrides based on light elements

    Energy Technology Data Exchange (ETDEWEB)

    Orgaz, E. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico)]. E-mail: orgaz@eros.pquim.unam.mx; Membrillo, A. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico); Castaneda, R. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico); Aburto, A. [Departamento de Fisica, Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico)

    2005-12-08

    Ternary hydrides based on light elements are interesting owing to the high available energy density. In this work we focused into the electronic structure of a series of known systems having the general formula AMH{sub 4}(A=Li,Na,M=B,Al). We computed the energy bands and the total and partial density of states using the linear-augmented plane waves method. In this report, we discuss the chemical bonding in this series of complex hydrides.

  20. Accelerator physics in ERL based polarized electron ion collider

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Yue [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2015-05-03

    This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.

  1. Diffusion of Electronic Medical Record Based Public Hospital Information Systems

    OpenAIRE

    Cho, Kyoung Won; Kim, Seong Min; An, Chang-Ho; Chae, Young Moon

    2015-01-01

    Objectives This study was conducted to evaluate the adoption behavior of a newly developed Electronic Medical Record (EMR)-based information system (IS) at three public hospitals in Korea with a focus on doctors and nurses. Methods User satisfaction scores from four performance layers were analyzed before and two times after the newly develop system was introduced to evaluate the adoption process of the IS with Rogers' diffusion theory. Results The 'intention to use' scores, the most importan...

  2. Electronic Project of Taxation Based on EC Under Single Nation

    Institute of Scientific and Technical Information of China (English)

    WANG Tao; ZENG Xiao-ping

    2002-01-01

    Because of no real location and its virtual interaction, the information flow, the cash flow and the logistic flow of EC(Electronic Commerce) are to be separated individually. So the traditional taxation based on those three flows is challenged. Under this condition, this paper researches how to levy taxes on EC through internet using internet technology. As to simplify the model, it relates under a single nation. But it will also give some measures about the international trades.

  3. 微束X射线荧光光谱分析在法医学鉴定中的应用进展%Progress in Application of Microbeam X-ray Fluorescence Spectroscopy in Forensic Science

    Institute of Scientific and Technical Information of China (English)

    苏会芳; 刘超; 胡孙林; 王松才; 孙立敏; 黄炜; 张小婷; 李双琳

    2013-01-01

    微束X射线荧光(microbeam X-ray fluorescence,micro-XRF)光谱技术是近年来兴起的一种微束分析技术,以其灵敏度高、所需检材微少、检测精确、非破坏性等优点而得到广泛的应用,近年来micro-XRF在司法鉴定中的应用也逐渐增多.本文根据国内外近期micro-XRF在法医学应用方面的研究进展,概述了其在射击残留物、指纹显像、毒品来源及生产工艺等物证鉴别方面及其在犯罪现场分析等方面的应用.近年来智能、便携化的micro-XRF技术设备已经开始得到应用,相信其在法医学鉴定中将得到更广泛的普及和应用.%Microbeam X-ray fluorescence (micro-XRF) spectrometry has been raised as an analytical technique of microbeam during the recent years. With its advantages of high sensitivity,small sample requirement,high testing accuracy and non-destruction,the technique is widely utilized in forensic science. This review bases on recent researches at home and abroad,describes its applications including identification of gunshot residue,visualization of fingerprints,discrimination of drug source,production process,and other material evidences of analysis in crime scene. Thanks to the advances in technology,intelligent and portable micro-XRF equipment has appeared to be applied. It is believed that it may be more popular and frequent in administration of forensic science in the near future.

  4. THE ELECTRONIC MARKET LIBERALIZATION IN A KNOWLEDGE BASED ECONOMY

    Directory of Open Access Journals (Sweden)

    Stegăroiu Carina-Elena

    2013-04-01

    Full Text Available In the current context of economic globalization and the advent of the virtual business environment, organizations have registered profound transformations that force companies to reconsider their strategic objectives, especially taking into consideration the opportunities created by the new information and communication technologies. Regardless of their reactive or proactive strategies when facing the changes in the competition, most companies in the developed countries and more and more of the Romanian enterprises are interested in developing technologies and information systems at a intra, inter and extra organizational level, with integrated traits, which are capable to sustain both the managerial process and the traditional functions of the organization. That being said, we herald now the expansion of the electronic commerce or eCommerce, which represents the automatization of the commercial transaction by using information systems and communication technologies. Developing an eCommerce system based on a business-to-business application consists of de-structuring the chain of value in managerial processes and then re-structuring it in order to identify the areas that can be made efficient through electronic means. This study is meant to aid the development of existing models by developing the services in certain less accessible to electronic commerce areas of a knowledge-based economy. As it stands, electronic commerce offers the opportunity of selling products world wide and this increasing the number of potential clients by eliminating the geographical barriers between buyers and seller. Opting for electronic commerce is a solution when the company wants to diversify its services and when it wants to reduce market related costs.

  5. Electronic shift register memory based on molecular electron-transfer reactions

    International Nuclear Information System (INIS)

    The design of a shift register memory at the molecular level is described in detail. The memory elements are based on a chain of electron-transfer molecules incorporated on a very large scale integrated (VLSI) substrate, and the information is shifted by photoinduced electron-transfer reactions. The design requirements for such a system are discussed, and several realistic strategies for synthesizing these systems are presented. The immediate advantage of such a hybrid molecular/VLSI device would arise from the possible information storage density. The prospect of considerable savings of energy per bit processed also exists. This molecular shift register memory element design solves the conceptual problems associated with integrating molecular size components with larger (micron) size features on a chip

  6. Organic photovoltaic cells based on unconventional electron donor fullerene and electron acceptor copper hexadecafluorophthalocyanine

    Science.gov (United States)

    Yang, J. L.; Sullivan, P.; Schumann, S.; Hancox, I.; Jones, T. S.

    2012-01-01

    We demonstrate organic discrete heterojunction photovoltaic cells based on fullerene (C60) and copper hexadecafluorophthalocyanine (F16CuPc), in which the C60 and F16CuPc act as the electron donor and the electron acceptor, respectively. The C60/F16CuPc cells fabricated with conventional and inverted architectures both exhibit comparable power conversion efficiencies. Furthermore, we show that the photocurrent in both cells is generated by a conventional exciton dissociation mechanism rather than the exciton recombination mechanism recently proposed for a similar C60/F16ZnPc system [Song et al., J. Am. Chem. Soc. 132, 4554 (2010)]. These results demonstrate that new unconventional material systems are a potential way to fabricate organic photovoltaic cells with inverted as well as conventional architectures.

  7. A Group Signature Based Electronic Toll Pricing System

    CERN Document Server

    Chen, Xihui; Mauw, Sjouke; Pang, Jun

    2011-01-01

    With the prevalence and development of GNSS technologies, location-based vehicle services (LBVS) have experienced a rapid growth in recent years. However, location is a sensitive and private piece of information, so the design and development of such services just take the clients' privacy concerns into account. In this paper, we propose a new electronic toll pricing system based on group signatures, which provides a strong guarantee for the clients' anonymity within groups. Our system achieves a balance between privacy and the communication overhead imposed upon the users.

  8. Atomic Electronic Contract Protocol Based on Convertible Signature

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-chun; WANG Li-na; ZHANG Huan-guo

    2005-01-01

    A new class of atomicity, namely contract atomicity is presented. A new technical strategy based on convertible signature and two-phase commitment is proposed for implementing atomicity of electronic contract protocol. A new atomic contract signing protocol is given out by using ElGamal-like convertible undeniable signature and commitment of conversion key, and another new atomic contract signing protocol is brought forward by using RSA-based convertible undeniable signature scheme and commitment of conversion key.These two new protocols are proved to be of atomicity, fairness, privacy, non-repudiation.

  9. Pressure induced phase transition behaviour in -electron based dialuminides

    Indian Academy of Sciences (India)

    P Ch Sahu; N V Chandra Shekar

    2000-05-01

    The rare-earth and actinide based compounds are endowed with several exotic physical and chemical properties due to the presence of -electrons. These properties exhibit interesting changes under the action of various thermodynamic fields and hence continues to be a subject of extensive research. For instance, under pressure, the nature of -electrons can be changed from localized to itinerant, leading to a variety of changes in their structural, physical and chemical properties. The present review on the high pressure phase transition behaviour of dialuminides of rare earths and actinides is an outcome of research in our laboratory during the last five years using a unique combination of a Guinier diffractometer and a diamond anvil cell built in-house. To bring out the correlations between the compressibility and structural behaviour with the electronic structure, we have also carried out electronic structure calculation. Further, the usefulness of Villars' three parameter structure maps in predicting pressure induced structural transitions has been explored and this has been illustrated with the available phase transition data.

  10. A molecularly based theory for electron transfer reorganization energy

    International Nuclear Information System (INIS)

    Using field-theoretic techniques, we develop a molecularly based dipolar self-consistent-field theory (DSCFT) for charge solvation in pure solvents under equilibrium and nonequilibrium conditions and apply it to the reorganization energy of electron transfer reactions. The DSCFT uses a set of molecular parameters, such as the solvent molecule’s permanent dipole moment and polarizability, thus avoiding approximations that are inherent in treating the solvent as a linear dielectric medium. A simple, analytical expression for the free energy is obtained in terms of the equilibrium and nonequilibrium electrostatic potential profiles and electric susceptibilities, which are obtained by solving a set of self-consistent equations. With no adjustable parameters, the DSCFT predicts activation energies and reorganization energies in good agreement with previous experiments and calculations for the electron transfer between metallic ions. Because the DSCFT is able to describe the properties of the solvent in the immediate vicinity of the charges, it is unnecessary to distinguish between the inner-sphere and outer-sphere solvent molecules in the calculation of the reorganization energy as in previous work. Furthermore, examining the nonequilibrium free energy surfaces of electron transfer, we find that the nonequilibrium free energy is well approximated by a double parabola for self-exchange reactions, but the curvature of the nonequilibrium free energy surface depends on the charges of the electron-transferring species, contrary to the prediction by the linear dielectric theory

  11. A molecularly based theory for electron transfer reorganization energy

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Bilin; Wang, Zhen-Gang, E-mail: zgw@cheme.caltech.edu [Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-12-14

    Using field-theoretic techniques, we develop a molecularly based dipolar self-consistent-field theory (DSCFT) for charge solvation in pure solvents under equilibrium and nonequilibrium conditions and apply it to the reorganization energy of electron transfer reactions. The DSCFT uses a set of molecular parameters, such as the solvent molecule’s permanent dipole moment and polarizability, thus avoiding approximations that are inherent in treating the solvent as a linear dielectric medium. A simple, analytical expression for the free energy is obtained in terms of the equilibrium and nonequilibrium electrostatic potential profiles and electric susceptibilities, which are obtained by solving a set of self-consistent equations. With no adjustable parameters, the DSCFT predicts activation energies and reorganization energies in good agreement with previous experiments and calculations for the electron transfer between metallic ions. Because the DSCFT is able to describe the properties of the solvent in the immediate vicinity of the charges, it is unnecessary to distinguish between the inner-sphere and outer-sphere solvent molecules in the calculation of the reorganization energy as in previous work. Furthermore, examining the nonequilibrium free energy surfaces of electron transfer, we find that the nonequilibrium free energy is well approximated by a double parabola for self-exchange reactions, but the curvature of the nonequilibrium free energy surface depends on the charges of the electron-transferring species, contrary to the prediction by the linear dielectric theory.

  12. Advanced electron crystallography through model-based imaging.

    Science.gov (United States)

    Van Aert, Sandra; De Backer, Annick; Martinez, Gerardo T; den Dekker, Arnold J; Van Dyck, Dirk; Bals, Sara; Van Tendeloo, Gustaaf

    2016-01-01

    The increasing need for precise determination of the atomic arrangement of non-periodic structures in materials design and the control of nanostructures explains the growing interest in quantitative transmission electron microscopy. The aim is to extract precise and accurate numbers for unknown structure parameters including atomic positions, chemical concentrations and atomic numbers. For this purpose, statistical parameter estimation theory has been shown to provide reliable results. In this theory, observations are considered purely as data planes, from which structure parameters have to be determined using a parametric model describing the images. As such, the positions of atom columns can be measured with a precision of the order of a few picometres, even though the resolution of the electron microscope is still one or two orders of magnitude larger. Moreover, small differences in average atomic number, which cannot be distinguished visually, can be quantified using high-angle annular dark-field scanning transmission electron microscopy images. In addition, this theory allows one to measure compositional changes at interfaces, to count atoms with single-atom sensitivity, and to reconstruct atomic structures in three dimensions. This feature article brings the reader up to date, summarizing the underlying theory and highlighting some of the recent applications of quantitative model-based transmisson electron microscopy. PMID:26870383

  13. RFID-based Electronic Identity Security Cloud Platform in Cyberspace

    Directory of Open Access Journals (Sweden)

    Bing Chen

    2012-07-01

    Full Text Available With the moving development of networks, especially Internet of Things, electronic identity administration in cyberspace is becoming more and more important. And personal identity management in cyberspace associated with individuals in reality has been one significant and urgent task for the further development of information construction in China. So this paper presents a RFID-based electronic identity security cloud platform in cyberspace to implement an efficient security management of cyber personal identity, and designs and realizes a strong and pervasive security cloud service platform, and discusses key technology including security authentication mechanism for the electronic identity card, super high frequency RFID with eID cards, multilevel privacy protection mechanism, security cloud service, security isolation and single-oriented transmission, and boundary security gateway protection, and it can well apply to personal identity management with virtual roles of citizens in cyberspace such as E-Government and E-Business, and the electronic identity security platform has been primary implemented and achieved good effects in actual applications.

  14. Antibody meets the microbeam - or how to find neurofibrillary tangles

    International Nuclear Information System (INIS)

    In biomedical research the distributions of physiologically or pathologically active elements around or in a certain structure (e.g. tangles, plaques or different cell types) are often of great interest. Therefore, μPIXE analyses are applied to yield quantitative and spatially resolved concentration images of the elements of interest. However, the localisation of the structures to be examined is sometimes scarcely practicable or even impossible. This paper proposes a method of localising the areas of interest for μPIXE analysis. The method is based on the application of a suitable antibody tagged with a single elemental marker (e.g. Ni, Co, Cd, Ag or Au). The antibody then binds selectively to the structures of interest. The elemental marker is detectable via μPIXE, thus, showing finally the structure of interest via the bound antibody. The versatility of the antibodies in combination with the easily applied marker facilitates the localisation of a variety of structures in both light microscopy and μPIXE-imaging. The method is demonstrated on several cellular and subcellular structures in the brain. The elemental concentrations of two consecutive slices, one stained with Ni-enhanced antibody, the other unstained control, are compared to show the feasibility of trace elemental analysis for particular elements in spite if immunohistochemical structure identification. It has to be stated that the proposed technique will not work for free diffusing elements (like Na, Cl, K and Ca) whose concentrations can be altered by wet sample preparation

  15. Antibody meets the microbeam - or how to find neurofibrillary tangles

    Energy Technology Data Exchange (ETDEWEB)

    Morawski, Markus [Paul-Flechsig-Institut fuer Hirnforschung, Universitaet Leipzig, Jahnallee 59, 04109 Leipzig (Germany)]. E-mail: morm@medizin.uni-leipzig.de; Reinert, Tilo [Nukleare Festkoerperphysik, Universitaet Leipzig, Linnestr. 5, 04103 Leipzig (Germany); Meinecke, Christoph [Nukleare Festkoerperphysik, Universitaet Leipzig, Linnestr. 5, 04103 Leipzig (Germany); Arendt, Thomas [Paul-Flechsig-Institut fuer Hirnforschung, Universitaet Leipzig, Jahnallee 59, 04109 Leipzig (Germany); Butz, T. [Nukleare Festkoerperphysik, Universitaet Leipzig, Linnestr. 5, 04103 Leipzig (Germany)

    2005-04-01

    In biomedical research the distributions of physiologically or pathologically active elements around or in a certain structure (e.g. tangles, plaques or different cell types) are often of great interest. Therefore, {mu}PIXE analyses are applied to yield quantitative and spatially resolved concentration images of the elements of interest. However, the localisation of the structures to be examined is sometimes scarcely practicable or even impossible. This paper proposes a method of localising the areas of interest for {mu}PIXE analysis. The method is based on the application of a suitable antibody tagged with a single elemental marker (e.g. Ni, Co, Cd, Ag or Au). The antibody then binds selectively to the structures of interest. The elemental marker is detectable via {mu}PIXE, thus, showing finally the structure of interest via the bound antibody. The versatility of the antibodies in combination with the easily applied marker facilitates the localisation of a variety of structures in both light microscopy and {mu}PIXE-imaging. The method is demonstrated on several cellular and subcellular structures in the brain. The elemental concentrations of two consecutive slices, one stained with Ni-enhanced antibody, the other unstained control, are compared to show the feasibility of trace elemental analysis for particular elements in spite if immunohistochemical structure identification. It has to be stated that the proposed technique will not work for free diffusing elements (like Na, Cl, K and Ca) whose concentrations can be altered by wet sample preparation.

  16. Thin-film chemical sensors based on electron tunneling

    Science.gov (United States)

    Khanna, S. K.; Lambe, J.; Leduc, H. G.; Thakoor, A. P.

    1985-01-01

    The physical mechanisms underlying a novel chemical sensor based on electron tunneling in metal-insulator-metal (MIM) tunnel junctions were studied. Chemical sensors based on electron tunneling were shown to be sensitive to a variety of substances that include iodine, mercury, bismuth, ethylenedibromide, and ethylenedichloride. A sensitivity of 13 parts per billion of iodine dissolved in hexane was demonstrated. The physical mechanisms involved in the chemical sensitivity of these devices were determined to be the chemical alteration of the surface electronic structure of the top metal electrode in the MIM structure. In addition, electroreflectance spectroscopy (ERS) was studied as a complementary surface-sensitive technique. ERS was shown to be sensitive to both iodine and mercury. Electrolyte electroreflectance and solid-state MIM electroreflectance revealed qualitatively the same chemical response. A modified thin-film structure was also studied in which a chemically active layer was introduced at the top Metal-Insulator interface of the MIM devices. Cobalt phthalocyanine was used for the chemically active layer in this study. Devices modified in this way were shown to be sensitive to iodine and nitrogen dioxide. The chemical sensitivity of the modified structure was due to conductance changes in the active layer.

  17. Low-voltage coherent electron imaging based on a single-atom electron

    CERN Document Server

    Chang, Wei-Tse; Hsu, Wei-Hao; Chang, Mu-Tung; Chen, Yi-Sheng; Hwu, En-Te; Hwang, Ing-Shouh

    2015-01-01

    It has been a general trend to develop low-voltage electron microscopes due to their high imaging contrast of the sample and low radiation damage. Atom-resolved transmission electron microscopes with voltages as low as 15-40 kV have been demonstrated. However, achieving atomic resolution at voltages lower than 10 kV is extremely difficult. An alternative approach is coherent imaging or phase retrieval imaging, which requires a sufficiently coherent source and an adequately small detection area on the sample as well as the detection of high-angle diffracted patterns with a sufficient resolution. In this work, we propose several transmission-type schemes to achieve coherent imaging of thin materials (less than 5 nm thick) with atomic resolution at voltages lower than 10 kV. Experimental schemes of both lens-less and lens-containing designs are presented and the advantages and challenges of these schemes are discussed. Preliminary results based on a highly coherent single-atom electron source are presented. The ...

  18. Web based electronic log book for Indus-2

    International Nuclear Information System (INIS)

    Raja Ramanna Centre for Advanced Technology (RRCAT), Indore, India has a 20 MeV Microtron injector, a 450/700 MeV Booster Synchrotron, a 450 MeV Storage Ring Indus-1 and another 2.5 GeV Storage Ring Indus-2. Both the machines are national facilities and are run round the clock to provide synchrotron radiation to users as well as carrying out machine related studies. In a multi accelerator complex like this, an effective system for electronically recording experimental data, machine status, events etc is considered essential. Considering the advantages of Internet technologies, a first version of web based Electronic Logbook (Elogbook) has been developed using HTML, JavaScript, java servlets and SQL database. This Elogbook will provide convenient way to review machine performance, help in problem diagnosis and improve communications among working teams. (author)

  19. Single-ZnO-Nanobelt-Based Single-Electron Transistors

    Science.gov (United States)

    Ji, Xiao-Fan; Xu, Zheng; Cao, Shuo; Qiu, Kang-Sheng; Tang, Jing; Zhang, Xi-Tian; Xu, Xiu-Lai

    2014-06-01

    We fabricate single electron transistors based on a single ZnO nanobelt using standard micro-fabrication techniques. The transport properties of the devices are characterized at room temperature and at low temperature (4.2 K). At room temperature, the source-drain current increases linearly as the bias voltage increases, indicating a good ohmic contact in the transistors. At 4.2 K, a Coulomb blockade regime is observed up to a bias voltage of a few millivolts. With scanning the back gate voltage, Coulomb oscillations can be clearly resolved with a period around 1 V. From the oscillations, the charging energy for the single electron transistor is calculated to be about 10 meV, which suggests that confined quantum dots exist with sizes around 35 nm in diameter. The irregular Coulomb diamonds are observed due to the multi-tunneling junctions between dots in the nanobelt.

  20. Design of wireless electronic stethoscope based on zigbee

    CERN Document Server

    Patil, D D Kadam

    2012-01-01

    Heart sound stethoscope is primary stage to access diseases. In this paper design of an electronic stethoscope with the functions of wireless transmission is discussed. This electronic stethoscope based on embedded processor. The data can be transmitted through wireless transmission using Zigbee module. A microphone is used to pick up the sound of the heart beat. Acoustic stethoscope can be changed into a digital stethoscope by inserting an electric capacity microphone into its head. The signal is processed and amplified to play with or without earphone. Heart sounds are processed, sampled and sent wirelessly using Zigbee module so that multiple doctors can do auscultation. PC connectivity is provided through serial port where from audio and video can be made available through LAN and internet for telemedicine consultation. Heart beat signals are sensed, sent, displayed, monitored, stored, reviewed, and analysed with ease.

  1. Graphene gate electrode for MOS structure-based electronic devices.

    Science.gov (United States)

    Park, Jong Kyung; Song, Seung Min; Mun, Jeong Hun; Cho, Byung Jin

    2011-12-14

    We demonstrate that the use of a monolayer graphene as a gate electrode on top of a high-κ gate dielectric eliminates mechanical-stress-induced-gate dielectric degradation, resulting in a quantum leap of gate dielectric reliability. The high work function of hole-doped graphene also helps reduce the quantum mechanical tunneling current from the gate electrode. This concept is applied to nonvolatile Flash memory devices, whose performance is critically affected by the quality of the gate dielectric. Charge-trap flash (CTF) memory with a graphene gate electrode shows superior data retention and program/erase performance that current CTF devices cannot achieve. The findings of this study can lead to new applications of graphene, not only for Flash memory devices but also for other high-performance and mass-producible electronic devices based on MOS structure which is the mainstream of the electronic device industry.

  2. Agent-based services for B2B electronic commerce

    Science.gov (United States)

    Fong, Elizabeth; Ivezic, Nenad; Rhodes, Tom; Peng, Yun

    2000-12-01

    The potential of agent-based systems has not been realized yet, in part, because of the lack of understanding of how the agent technology supports industrial needs and emerging standards. The area of business-to-business electronic commerce (b2b e-commerce) is one of the most rapidly developing sectors of industry with huge impact on manufacturing practices. In this paper, we investigate the current state of agent technology and the feasibility of applying agent-based computing to b2b e-commerce in the circuit board manufacturing sector. We identify critical tasks and opportunities in the b2b e-commerce area where agent-based services can best be deployed. We describe an implemented agent-based prototype system to facilitate the bidding process for printed circuit board manufacturing and assembly. These activities are taking place within the Internet Commerce for Manufacturing (ICM) project, the NIST- sponsored project working with industry to create an environment where small manufacturers of mechanical and electronic components may participate competitively in virtual enterprises that manufacture printed circuit assemblies.

  3. Electron-ion plasma modification of Al-based alloys

    Science.gov (United States)

    Ivanov, Yurii; Rygina, Mariya; Petrikova, Elizaveta; Krysina, Olga; Teresov, Anton; Ivanova, Olga; Ikonnikova, Irina

    2016-01-01

    The paper reports on the study where we analyzed the surface structure and strength properties of coated Al alloys modified by electron-ion plasma treatment. The Al alloys were deposited with a thin (≈0.5 μm) TiCu film coating (TiCu-Al system) and with a hard TiCuN coating (TiCuN-AlSi system) on a TRIO vacuum setup in the plasma of low-pressure arc discharges. The temperature fields and phase transformations in the film-substrate system were estimated by numerical simulation in a wide range of electron energy densities (5-30 J/cm2) and pulse durations (50-200 μs). The calculations allowed us to determine the threshold energy density and pulse duration at which the surface structure of the irradiated Al-based systems is transformed in a single-phase state (solid or liquid) and in a two-phase state (solid plus liquid). The elemental composition, defect structure, phase state, and lattice state in the modified surface layers were examined by optical, scanning, and transmission electron microscopy, and by X-ray diffraction analysis. The mechanical characteristics of the modified layers were studied by measuring the hardness and Young's modulus. The tribological properties of the modified layers were analyzed by measuring the wear resistance and friction coefficient. It is shown that melting and subsequent high-rate crystallization of the TiCu-Al system makes possible a multiphase Al-based surface structure with the following characteristics: crystallite size ranging within micrometer, microhardness of more than 3 times that in the specimen bulk, and wear resistance ≈1.8 times higher compared to the initial material. Electron beam irradiation of the TiCuN-AlSi system allows fusion of the coating into the substrate, thus increasing the wear resistance of the material ≈2.2 times at a surface hardness of ˜14 GPa.

  4. Two-dimensional materials based transparent flexible electronics

    Science.gov (United States)

    Yu, Lili; Ha, Sungjae; El-Damak, Dina; McVay, Elaine; Ling, Xi; Chandrakasan, Anantha; Kong, Jing; Palacios, Tomas

    2015-03-01

    Two-dimensional (2D) materials have generated great interest recently as a set of tools for electronics, as these materials can push electronics beyond traditional boundaries. These materials and their heterostructures offer excellent mechanical flexibility, optical transparency, and favorable transport properties for realizing electronic, sensing, and optical systems on arbitrary surfaces. These thin, lightweight, bendable, highly rugged and low-power devices may bring dramatic changes in information processing, communications and human-electronic interaction. In this report, for the first time, we demonstrate two complex transparent flexible systems based on molybdenum disulfide (MoS2) grown by chemical vapor method: a transparent active-matrix organic light-emitting diode (AMOLED) display and a MoS2 wireless link for sensor nodes. The 1/2 x 1/2 square inch, 4 x 5 pixels AMOLED structures are built on transparent substrates, containing MoS2 back plane circuit and OLEDs integrated on top of it. The back plane circuit turns on and off the individual pixel with two MoS2 transistors and a capacitor. The device is designed and fabricated based on SPICE simulation to achieve desired DC and transient performance. We have also demonstrated a MoS2 wireless self-powered sensor node. The system consists of as energy harvester, rectifier, sensor node and logic units. AC signals from the environment, such as near-field wireless power transfer, piezoelectric film and RF signal, are harvested, then rectified into DC signal by a MoS2 diode. CIQM, CICS, SRC.

  5. Distribution of lead in the brain tissues from DNTC patients using synchrotron radiation microbeams

    Energy Technology Data Exchange (ETDEWEB)

    Ide-Ektessabi, Ari [International Innovation Center, Kyoto University, Kyoto (Japan); Ota, Yukihide [Department of Precision Engineering, Kyoto University, Yoshida Honnmachi, Sakyo-ku, Kyoto (Japan)]. E-mail: h51167@sakura.kudpc.kyoto-u.ac.jp; Ishihara, Ryoko [Department of Psychiatry, Nagoya University, Graduate School of Medicine, Nagoya (Japan); Mizuno, Yutaka [Obu Dementia Care Research and Training Center, Obu (Japan); Takeuchi, Tohru [Department of Psychiatry, Nagoya University, Graduate School of Medicine, Nagoya (Japan)

    2005-12-15

    Diffuse neurofibrillary tangles with calcification (DNTC) is a form of dementia with certain characteristics. Its pathology is characterized by cerebrum atrophy, calcification on globus pallidus and dentate nucleus and diffuse neurofibrillary tangles without senile plaques. In the present study brain tissues were prepared from patients with patients DNTC, calcified and non-calcified Alzheimer's disease (AD) patients. The brain tissues were examined non-destructively by X-ray fluorescence (XRF) spectroscopy using synchrotron radiation (SR) microbeams for trace metallic elements Ca, Fe, Cu, Zn and Pb. The XRF analysis showed that there were Pb concentrations in the calcified areas in the brain tissues with both DNTC and AD but there was none in those with non-calcified AD.

  6. Thin silicon strip detectors for beam monitoring in Micro-beam Radiation Therapy

    CERN Document Server

    Povoli, Marco; Bravin, Alberto; Cornelius, Iwan; Bräuer-Krisch, Elke; Fournier, Pauline; Hansen, Thor-Erik; Kok, Angela; Lerch, Michael; Monakhov, Edouard; Morse, John; Petasecca, Marco; Requardt, Herwig; Rosenfeld, Anatoly; Röhrich, Dieter; Sandaker, Heidi; Salomé, Murielle; Stugu, Bjarne

    2015-01-01

    Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any...

  7. Single-Ion Microbeam for Applications in Radiobiology: State of the Art

    Institute of Scientific and Technical Information of China (English)

    Hu Zhiwen; Wu Lijun; Yu Zengliang

    2005-01-01

    Single-Ion Microbeam (SIM) is uniquely capable of precisely delivering a predefined number of charged particles (precise doses of radiation) to individual cells or sub-cellular targets in situ. Since the early 1990's, there has been an ever-increasing interest in developing and applying the SIM technique to problems in radiobiology for studies of cell and tissue damaged by ionizing radiations. Potential applications for SIM in radiobiology continues to grow and have been diversified. There are currently more than 14 SIM facilities worldwide, and they have been in a constant state of evolution. This paper reviews the current state of SIM research worldwide and the related pivotal technological developments in the fields of both biophysics and radiobiology.Representative applications and the perspective of SIM are also introduced and discussed.

  8. Design of the CAS-LIBB Single-Ion Microbeam Endstation Ⅱ

    Institute of Scientific and Technical Information of China (English)

    XU Yongjian; HU Zhiwen; CHEN Lianyun; XU Mingliang; ZHAN Furu; YU Zengliang

    2008-01-01

    Cellular micro-irradiation is now recognized as a powerful technique to unveil the mechanisms of interaction between ionizing radiation and living cells or tissues. The single-ion microbeam (SIM) is uniquely capable of delivering precisely the predefined number of charged particles (precise doses of radiation) to specific individual cells or sub-cellular targets in situ. No active research in the field concerning the original process of the interaction between low-energy ions and complicated organisms has been reported yet. To address this challenge, the aim of the present design is to further wrestle with multi-dimensional quantitative information from living cells traversed by an exact number of ions real-time rather than endpoints, in the time scale from milliseconds to days.

  9. An ultra-thin Schottky diode as a transmission particle detector for biological microbeams

    International Nuclear Information System (INIS)

    We fabricated ultrathin metal-semiconductor Schottky diodes for use as transmission particle detectors in the biological microbeam at Columbia University's Radiological Research Accelerator Facility (RARAF). The RARAF microbeam can deliver a precise dose of ionizing radiation in cell nuclei with sub-micron precision. To ensure an accurate delivery of charged particles, the facility currently uses a commercial charged-particle detector placed after the sample. We present here a transmission detector that will be placed between the particle accelerator and the biological specimen, allowing the irradiation of samples that would otherwise block radiation from reaching a detector behind the sample. Four detectors were fabricated with co-planar gold and aluminum electrodes thermally evaporated onto etched n-type crystalline silicon substrates, with device thicknesses ranging from 8.5 μm - 13.5 μm. We show coincident detections and pulse-height distributions of charged particles in both the transmission detector and the commercial detector above it. Detections are demonstrated at a range of operating conditions, including incoming particle type, count rate, and beam location on the detectors. The 13.5 μm detector is shown to work best to detect 2.7 MeV protons (H+), and the 8.5 μm detector is shown to work best to detect 5.4 MeV alpha particles (4He++). The development of a transmission detector enables a range of new experiments to take place at RARAF on radiation-stopping samples such as thick tissues, targets that need immersion microscopy, and integrated microfluidic devices for handling larger quantities of cells and small organisms.

  10. Carbon nanotube based pressure sensor for flexible electronics

    Energy Technology Data Exchange (ETDEWEB)

    So, Hye-Mi [Department of Nano Mechanics, Nanomechanical Systems Research Division, Korea Institute of Machinery and Materials, Daejeon 305-343 (Korea, Republic of); Sim, Jin Woo [Advanced Nano Technology Ltd., Seoul 132-710 (Korea, Republic of); Kwon, Jinhyeong [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Yun, Jongju; Baik, Seunghyun [SKKU Advanced Institute of Nanotechnology (SAINT), Department of Energy Science and School of Mechanical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Chang, Won Seok, E-mail: paul@kimm.re.kr [Department of Nano Mechanics, Nanomechanical Systems Research Division, Korea Institute of Machinery and Materials, Daejeon 305-343 (Korea, Republic of)

    2013-12-15

    Highlights: • The electromechanical change of vertically aligned carbon nanotubes. • Fabrication of CNT field-effect transistor on flexible substrate. • CNT based FET integrated active pressure sensor. • The integrated device yields an increase in the source-drain current under pressure. - Abstract: A pressure sensor was developed based on an arrangement of vertically aligned carbon nanotubes (VACNTs) supported by a polydimethylsiloxane (PDMS) matrix. The VACNTs embedded in the PDMS matrix were structurally flexible and provided repeated sensing operation due to the high elasticities of both the polymer and the carbon nanotubes (CNTs). The conductance increased in the presence of a loading pressure, which compressed the material and induced contact between neighboring CNTs, thereby producing a dense current path and better CNT/metal contacts. To achieve flexible functional electronics, VACNTs based pressure sensor was integrated with field-effect transistor, which is fabricated using sprayed semiconducting carbon nanotubes on plastic substrate.

  11. DOCCⅡ-based electronically tunable current-mode biquadratic filters

    Institute of Scientific and Technical Information of China (English)

    Wang Weidong

    2005-01-01

    A complete state variable current-mode biquadratic filter built by duo-output CCⅡ (DOCCⅡ) with variable current gain is presented. All the coefficients of the filter can be independently tuned through the variable current gain factors of the DOCCⅡ. Based on the principles upon which the general biquadratic filter was constructed, a universal electronically tunable current-mode filter is proposed which implements the low-pass, high-pass, band-pass, band-suppress and all-pass second order transfer functions simultaneously. The PSPICE simulations of frequency responses of second-order filter of are also given.

  12. Electron transport in gold colloidal nanoparticle-based strain gauges

    International Nuclear Information System (INIS)

    A systematic approach for understanding the electron transport mechanisms in resistive strain gauges based on assemblies of gold colloidal nanoparticles (NPs) protected by organic ligands is described. The strain gauges were fabricated from parallel micrometer wide wires made of 14 nm gold (Au) colloidal NPs on polyethylene terephthalate substrates, elaborated by convective self-assembly. Electron transport in such devices occurs by inter-particle electron tunneling through the tunnel barrier imposed by the organic ligands protecting the NPs. This tunnel barrier was varied by changing the nature of organic ligands coating the nanoparticles: citrate (CIT), phosphines (BSPP, TDSP) and thiols (MPA, MUDA). Electro-mechanical tests indicate that only the gold NPs protected by phosphine and thiol ligands yield high gauge sensitivity. Temperature-dependent resistance measurements are explained using the ‘regular island array model’ that extracts transport parameters, i.e., the tunneling decay constant β and the Coulomb charging energy EC. This reveals that the Au-CIT nanoparticle assemblies exhibit a behavior characteristic of a strong-coupling regime, whereas those of Au-BSPP, Au-TDSP, Au-MPA and Au-MUDA nanoparticles manifest a weak-coupling regime. A comparison of the parameters extracted from the two methods indicates that the most sensitive gauges in the weak-coupling regime feature the highest β. Moreover, the EC values of these 14 nm NPs cannot be neglected in determining the β values. (paper)

  13. Diamond-based heat spreaders for power electronic packaging applications

    Science.gov (United States)

    Guillemet, Thomas

    As any semiconductor-based devices, power electronic packages are driven by the constant increase of operating speed (higher frequency), integration level (higher power), and decrease in feature size (higher packing density). Although research and innovation efforts have kept these trends continuous for now more than fifty years, the electronic packaging technology is currently facing a challenge that must be addressed in order to move toward any further improvements in terms of performances or miniaturization: thermal management. Thermal issues in high-power packages strongly affect their reliability and lifetime and have now become one of the major limiting factors of power modules development. Thus, there is a strong need for materials that can sustain higher heat flux levels while safely integrating into the electronic package architecture. In such context, diamond is an attractive candidate because of its outstanding thermal conductivity, low thermal expansion, and high electrical resistivity. Its low heat capacity relative to metals such as aluminum or copper makes it however preferable for heat spreading applications (as a heat-spreader) rather than for dissipating the heat flux itself (as a heat sink). In this study, a dual diamond-based heat-spreading solution is proposed. Polycrystalline diamond films were grown through laser-assisted combustion synthesis on electronic substrates (in the U.S) while, in parallel, diamond-reinforced copper-matrix composite films were fabricated through tape casting and hot pressing (in France). These two types of diamond-based heat-spreading films were characterized and their microstructure and chemical composition were related to their thermal performances. Particular emphasize was put on the influence of interfaces on the thermal properties of the materials, either inside a single material (grain boundaries) or between dissimilar materials (film/substrate interface, matrix/reinforcement interface). Finally, the packaging

  14. Towards Evidence-Based Understanding of Electronic Data Sources

    DEFF Research Database (Denmark)

    Chen, Lianping; Ali Babar, Muhammad; Zhang, He

    2010-01-01

    Identifying relevant papers from various Electronic Data Sources (EDS) is one of the key activities of conducting these kinds of studies. Hence, the selection of EDS for searching the potentially relevant papers is an important decision, which can affect a study’s coverage of relevant papers....... Researchers usually select EDS mainly based on personal knowledge, experience, and preferences and/or recommendations by other researchers. We believe that building an evidence-based understanding of EDS can enable researchers to make more informed decisions about the selection of EDS. This paper reports our...... initial effort towards this end. We propose an initial set of metrics for characterizing the EDS from the perspective of the needs of secondary studies. We explain the usage and benefits of the proposed metrics using the data gathered from two secondary studies. We also tried to synthesize the data from...

  15. Manganese oxide microswitch for electronic memory based on neural networks

    Science.gov (United States)

    Ramesham, R.; Daud, T.; Moopenn, A.; Thakoor, A. P.; Khanna, S. K.

    1989-01-01

    A solid-state, resistance tailorable, programmable-once, binary, nonvolatile memory switch based on manganese oxide thin films is reported. MnO(x) exhibits irreversible memory switching from conducting (on) to insulating (off) state, with the off and on resistance ratio of greater than 10,000. The switching mechanism is current-triggered chemical transformation of a conductive MnO(2-Delta) to an insulating Mn2O3 state. The energy required for switching is of the order of 4-20 nJ/sq micron. The low switching energy, stability of the on and off states, and tailorability of the on state resistance make these microswitches well suited as programmable binary synapses in electronic associative memories based on neural network models.

  16. An Electronic Library-Based Learning Environment for Supporting Web-Based Problem-Solving Activities

    Science.gov (United States)

    Tsai, Pei-Shan; Hwang, Gwo-Jen; Tsai, Chin-Chung; Hung, Chun-Ming; Huang, Iwen

    2012-01-01

    This study aims to develop an electronic library-based learning environment to support teachers in developing web-based problem-solving activities and analyzing the online problem-solving behaviors of students. Two experiments were performed in this study. In study 1, an experiment on 103 elementary and high school teachers (the learning activity…

  17. Study of local strain distribution in semiconductor devices using high-resolution X-ray microbeam diffractometry

    International Nuclear Information System (INIS)

    High-resolution X-ray diffraction has been carried out by using a vertically and horizontally condensed X-ray microbeam at the Hyogo beamline (BL24XU) of SPring-8. The microbeam is 7x5 μm2 in size and it possesses a small angular divergence and a narrow energy bandwidth. The sample is a Si substrate on which thermal oxide films are fabricated with fine patterns. At the region of the line-and-space pattern, many periodic peaks lying along the transverse direction are observed in a reciprocal space map. Those patterns are attributed to some local strain distribution due to the patterned oxide film on the Si wafer

  18. Cell Locating with the Image Analysis System of the CAS-LIBB Single-Particle Microbeam Facility

    Institute of Scientific and Technical Information of China (English)

    Wang Xiaohua; Wang Shaohu; Yu Zengliang

    2005-01-01

    A single-particle microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering (LIBB), Chinese Academy of Sciences (CAS). At the CAS-LIBB microbeam facility, we have developed protocols to place exact numbers of charged particles through nuclear centroids of cells, at defined positions in the cytoplasm relative to the nucleus, and through defined fractions of cells in a population. In this paper, we address the methods for nucleus, cytoplasm and bystander (either a single or an exact number of ions is delivered to a certain percentage of cells in a population to study the bystander effects of radiation) irradiation in detail from the precision of target finding and cell locating in the image analysis system. Moreover, for cells touching slightly in an image, a watershed method is used to separate these touching objects;after that, the number of objects in an image is counted accurately and the irradiation points are located precisely.

  19. X-ray microbeam radiation therapy calculations, including polarisation effects, with the Monte Carlo code EGS5

    Energy Technology Data Exchange (ETDEWEB)

    Hugtenburg, Richard P., E-mail: r.p.hugtenburg@swansea.ac.u [School of Medicine, Swansea University, Swansea SA2 8PP (United Kingdom); Department of Medical Physics and Clinical Engineering, Abertawe Bro Morgannwg University, LHB, Swansea SA2 8QA (United Kingdom); Adegunloye, A.S.; Bradley, David A. [Department of Physics, Surrey University, Guildford (United Kingdom)

    2010-07-21

    Microbeam radiation therapy (MRT) is currently being considered for the treatment of glioblastoma multiforme. A high degree of dosimetric accuracy (around 5%) is known to be required for a successful outcome in conventional radiation therapy, Modelling of MRT beams, measurements and treatments have been performed with Monte Carlo methods using the code EGS5, which features improved physics models for low energy scattering processes including linear polarisation. Polarisation of the X-ray source leads to distortions in beam profiles that exceed the usual clinical tolerances. Changes in the energy spectrum also effect the response of many dosimetry systems. Anatomical (CT) data has been used in the dose calculations and the manipulation of dose data with the open-source software treatment planning system, PlanUNC, is demonstrated, in order that the therapeutic effects of the different components, e.g. the microbeam and scattered photons, can examined separately in relation to relevant anatomy.

  20. The accident of overexposure at the University hospital center of Toulouse. Expertise report n.1. Checking of experimental protocols of micro-beams calibration before and after dysfunction correction

    International Nuclear Information System (INIS)

    The regional center of stereotaxic radiosurgery of the University hospital center of Toulouse is equipped since april 2006 of a Novalis accelerator (Brainlab) devoted to the intra-skull stereotaxic radiosurgery. In april 2007, during an intercomparison of dosimetry computer files coming from different sites, the Brainlab society finds an anomaly in the files. The analysis made by the society concludes to to the use of an inappropriate detector for the measurement of a dosimetry parameter during the initial calibration of the accelerator. following this error, 145 patients (on the 172 treated by the service in question) suffer the consequences of an overdose whom importance is variable according the cases. The I.R.S.N. in charge of an expertise about the protocols of calibration of micro-beams before and after the correction of the dysfunction, took up with the search of the technical causes of the dysfunction. This report presents successively: the documents base on which is founded the expertise; the material of dosimetry and quality control necessary to the initial calibration of the device and to its follow-up; the formula made at the accelerator commissioning; the calibration of micro-beams in the two configurations that allows the device (micro-multi-knives and conic collimator) and the definition of parameters of the software of treatment planning; the maintenance and quality control implemented in the frame of its clinical use. (N.C.)

  1. Electron-ion plasma modification of Al-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Yurii, E-mail: yufi55@mail.ru [Institute of High-Current Electronics of the Siberian Branch of the Russian Academy of Sciences, 634055, Russia, Tomsk, 2/3 Akademicheskiy Ave (Russian Federation); National Research Tomsk State University, 634050, Russia, Tomsk, 36 Lenina Str (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050, Russia, Tomsk, 30 Lenina Str (Russian Federation); Rygina, Mariya, E-mail: l-7755me@mail.ru [National Research Tomsk Polytechnic University, Tomsk, 634050, Russia, Tomsk, 30 Lenina Str (Russian Federation); Petrikova, Elizaveta, E-mail: elizmarkova@yahoo.com; Krysina, Olga, E-mail: krysina-82@mail.ru; Teresov, Anton, E-mail: tad514@sibmail.com [Institute of High-Current Electronics of the Siberian Branch of the Russian Academy of Sciences, 634055, Russia, Tomsk, 2/3 Akademicheskiy Ave (Russian Federation); National Research Tomsk State University, 634050, Russia, Tomsk, 36 Lenina Str (Russian Federation); Ivanova, Olga, E-mail: ivaov@mail.ru; Ikonnikova, Irina, E-mail: irina-ikonnikova@yandex.ru [Tomsk State University of Architecture and Building, Tomsk, 634002, Russia, Tomsk, 2 Solyanaya Sq (Russian Federation)

    2016-01-15

    The paper reports on the study where we analyzed the surface structure and strength properties of coated Al alloys modified by electron-ion plasma treatment. The Al alloys were deposited with a thin (≈0.5 μm) TiCu film coating (TiCu-Al system) and with a hard TiCuN coating (TiCuN–AlSi system) on a TRIO vacuum setup in the plasma of low-pressure arc discharges. The temperature fields and phase transformations in the film–substrate system were estimated by numerical simulation in a wide range of electron energy densities (5–30 J/cm{sup 2}) and pulse durations (50–200 μs). The calculations allowed us to determine the threshold energy density and pulse duration at which the surface structure of the irradiated Al-based systems is transformed in a single-phase state (solid or liquid) and in a two-phase state (solid plus liquid). The elemental composition, defect structure, phase state, and lattice state in the modified surface layers were examined by optical, scanning, and transmission electron microscopy, and by X-ray diffraction analysis. The mechanical characteristics of the modified layers were studied by measuring the hardness and Young’s modulus. The tribological properties of the modified layers were analyzed by measuring the wear resistance and friction coefficient. It is shown that melting and subsequent high-rate crystallization of the TiCu–Al system makes possible a multiphase Al-based surface structure with the following characteristics: crystallite size ranging within micrometer, microhardness of more than 3 times that in the specimen bulk, and wear resistance ≈1.8 times higher compared to the initial material. Electron beam irradiation of the TiCuN–AlSi system allows fusion of the coating into the substrate, thus increasing the wear resistance of the material ≈2.2 times at a surface hardness of ∼14 GPa.

  2. Photon-Electron Interactions in Graphene-Based Heterojunctions

    Science.gov (United States)

    Liu, Fangze

    Graphene, a single layer of carbon atoms arranged in honeycomb lattice, has been one of the most attractive materials for fundamental and applied research in the past decade. Its unique electronic, optical, thermal, chemical and mechanical properties have lead to the discovery of new physics and many promising applications. In particular, research on photon-electron interaction in graphene-based heterojunctions has revealed a new route to design photoactive devices. In this thesis, I present our work on the synthesis of graphene by chemical vapor deposition (CVD) and the study of graphene-based optoelectronic devices. In addition to the conventional synthesis of graphene on copper (Cu) foils, we also present the CVD synthesis of graphene on a new substrate: palladium (Pd). Especially, we performed detailed study of the nucleation, evolution and morphology of graphene growth on Pd substrate. It helps us to understand the growth reaction mechanism and achieve controllable synthesis of graphene from single layer to multiple layers with different morphologies. We then studied the broadband and ultrasensitive photocurrent and photovoltage response of graphene/silicon (Si) Schottky diodes. For the same architecture, we identified a new photoconductive mode with ultra high photoconductive gain, namely "quantum carrier reinvestment (QCR)". A gain exceeding 107 A/W was demonstrated. The underlying physics of photon-electron interactions in these junctions were studied by a combination of optical characterization tools including Raman spectroscopy, UV-Vis spectroscopy and scanning optical microscopy. The results obtained have been discussed in the framework of the unique electronic band structure, density states, and mobility of graphene, along with the manner in witch photoexcited carrier behave under various externally tuned parameters. We also systematically studied the optimization of performance of graphene/Si and thin transparent graphite/Si junction solar cells and

  3. Electron-ion plasma modification of Al-based alloys

    International Nuclear Information System (INIS)

    The paper reports on the study where we analyzed the surface structure and strength properties of coated Al alloys modified by electron-ion plasma treatment. The Al alloys were deposited with a thin (≈0.5 μm) TiCu film coating (TiCu-Al system) and with a hard TiCuN coating (TiCuN–AlSi system) on a TRIO vacuum setup in the plasma of low-pressure arc discharges. The temperature fields and phase transformations in the film–substrate system were estimated by numerical simulation in a wide range of electron energy densities (5–30 J/cm2) and pulse durations (50–200 μs). The calculations allowed us to determine the threshold energy density and pulse duration at which the surface structure of the irradiated Al-based systems is transformed in a single-phase state (solid or liquid) and in a two-phase state (solid plus liquid). The elemental composition, defect structure, phase state, and lattice state in the modified surface layers were examined by optical, scanning, and transmission electron microscopy, and by X-ray diffraction analysis. The mechanical characteristics of the modified layers were studied by measuring the hardness and Young’s modulus. The tribological properties of the modified layers were analyzed by measuring the wear resistance and friction coefficient. It is shown that melting and subsequent high-rate crystallization of the TiCu–Al system makes possible a multiphase Al-based surface structure with the following characteristics: crystallite size ranging within micrometer, microhardness of more than 3 times that in the specimen bulk, and wear resistance ≈1.8 times higher compared to the initial material. Electron beam irradiation of the TiCuN–AlSi system allows fusion of the coating into the substrate, thus increasing the wear resistance of the material ≈2.2 times at a surface hardness of ∼14 GPa

  4. Backward chromosome movement in crane-fly spermatocytes after UV microbeam irradiation of the interzone and a kinetochore.

    Science.gov (United States)

    Wong, Raymond; Forer, Arthur

    2004-01-01

    Single anaphase chromosomes (in crane-fly spermatocytes) moved backwards after double irradiations with an ultraviolet light (UV) microbeam, first of the interzone and then of a kinetochore: the chromosome irradiated at the kinetochore moved backwards rapidly, across the equator and into the other half-spindle. High irradiation doses at the kinetochore were required to induce backward movement. Single irradiations of kinetochores or interzones were ineffective in inducing backward movements. PMID:15109986

  5. TRANSPARENCY IN ELECTRONIC BUSINESS NEGOTIATIONS – EVIDENCE BASED ANALYSIS

    Directory of Open Access Journals (Sweden)

    Radoslav Delina

    2014-12-01

    Full Text Available Purpose: In current economy, where ICT plays a crucial role for being competitive and effective, businesses are facing higher pressures of flexibility and efficiency than ever before. Transparency is often considered as a suitable mechanism for better market prices and more efficient market environment. Electronic business environment provides the possibility to set up more transparent environment and bring higher competitiveness and efficiency on the market. The paper analyse the impact of transparency on prices in e-procurement.Methodology: Reverse auctions are considered as transparent tool simulating in partial level real competition. Together, it allows to examine several levels of transparency set up in auction negotiation process. The impact of transparency on final prices was analysed on real data using relation based analysis were different situations of transparency set up is compared against achieved final price.Findings: Research results based on real data shows, that generally, the transparency in electronic reverse auction can lead to more negative prices agreed by purchasers as current scientific and commercial promotions.Research limitation: Significance of research results is limited due to still low readiness and skills of e-procurers. The validation of results is needed to realized within longer period of time and from environments with different level of e-readiness. Together, it reveal that transparency is more complex issue where the significance of transparency can reveal its sense in some specific situations on the market and negotiation.Value of paper: Evidenced based research reveal some controversy results which support new scientific efforts in microeconomics and socio-economic impact of ICT fields. Together, it affects real practitioners in way how to use and perceive claimed impact of reverse auction solutions.

  6. Studies of Electronic Conduction in Some Small Gallium Arsenic Based.

    Science.gov (United States)

    Whittington, Geoffrey

    Available from UMI in association with The British Library. Requires signed TDF. This thesis describes experimental investigations of the physics involved with low temperature electronic conduction in three different semiconductor systems. The research relies upon technological advances in fabrication of such semiconductor samples. The first work deals with the effects of quantum interference of electrons in some submicron size, heavily doped Gallium Arsenide wire samples. The interesting effect of aperiodic fluctuations in the magnetoresistance of these samples is studied, making use of recently formulated theory on the subject, and with experimental data taken over the magnetic field range 0 to 10 tesla. The results verify the connection between the mean amplitude of the fluctuations and the field correlation period, in terms of the correlation function introduced in the theory. The second work is on the impurity-assisted tunnelling conduction in a magnetic field of three thin rm n^{+}/n^{-}/n^ {+} GaAs sandwich layer structures. The conduction of the system is shown to be determined by impurities lying in the centre of the middle layer. This allows the connection to be made between the conductivity of the system in a magnetic field, and the field-dependent shape of the donor electron wavefunction. The relative variation in resistance with angle to an applied magnetic field was measured, and is shown to be in agreement with predictions based on calculations of the shape of a normalised hydrogenic state wavefunction in high magnetic fields. The third work concerns the tunnelling conduction of a symmetrical GaAs/(AlGa)As/GaAs hetero-barrier system. The current-voltage characteristics at low temperature are fully modelled for applied voltages up to 180mV, using conventional theory of tunnelling and a position-dependent effective mass in the barrier. Low current oscillations in the Fowler-Nordheim tunnelling regime, corresponding to quantum reflection at the

  7. In vivo pink-beam imaging and fast alignment procedure for rat brain lesion microbeam radiation therapy

    International Nuclear Information System (INIS)

    A fast 50 µm-accuracy alignment procedure has been developed for the radiosurgery of brain lesions in rats, using microbeam radiation therapy. A fast 50 µm-accuracy alignment procedure has been developed for the radiosurgery of brain lesions in rats, using microbeam radiation therapy. In vivo imaging was performed using the pink beam (35–60 keV) produced by the ID17 wiggler at the ESRF opened at 120 mm and filtered. A graphical user interface has been developed in order to define the irradiation field size and to position the target with respect to the skull structures observed in X-ray images. The method proposed here allows tremendous time saving by skipping the swap from white beam to monochromatic beam and vice versa. To validate the concept, the somatosensory cortex or thalamus of GAERS rats were irradiated under several ports using this alignment procedure. The magnetic resonance images acquired after contrast agent injection showed that the irradiations were selectively performed in these two expected brain regions. Image-guided microbeam irradiations have therefore been realised for the first time ever, and, thanks to this new development, the ID17 biomedical beamline provides a major tool allowing brain radiosurgery trials on animal patients

  8. Adaptive response in zebrafish embryos induced using microbeam protons as priming dose and X-ray photons as challenging dose

    International Nuclear Information System (INIS)

    In the studies reported here, a high-linear-energy-transfer (high-LET)-radiation dose was used to induce adaptive response in zebrafish embryos in vivo. Microbeam protons were used to provide the priming dose and X-ray photons were employed to provide the challenging dose. The microbeam irradiation system (Single-Particle Irradiation System to Cell, acronym as SPICE) at the National Institute of Radiological Sciences (NIRS), Japan, was employed to control and accurately quantify the number of protons at very low doses, viz., about 100 μGy. The embryos were dechorionated at 4 h post fertilization (hpf) and irradiated at 5 hpf by microbeam protons. For each embryo, ten irradiation points were arbitrarily chosen without overlapping with one another. To each irradiation point, 5, 10 or 20 protons each with an energy of 3.4 MeV were delivered. The embryos were returned back to the incubator until 10 hpf to further receive the challenging exposure, which was achieved using 2 Gy of X-ray irradiation, and then again returned to the incubator until 24 hpf for analyses. The levels of apoptosis in zebrafish embryos at 25 hpf were quantified through terminal dUTP transferase-mediated nick end-labeling (TUNEL) assay, with the apoptotic signals captured by a confocal microscope. The results revealed that 5 to 20 protons delivered at 10 points each on the embryos, or equivalently 110 to 430 μGy, could induce radioadaptive response in the zebrafish embryos in vivo. (author)

  9. Studies of the beam finding and targeting accuracy of the CAS-LIBB single-particle microbeam

    Institute of Scientific and Technical Information of China (English)

    Wang Xiao-Hua; Wu Li-Jun; Wang Shao-Hu; Yu Zeng-Liang; Wang Xu-Fei; Hu Zhi-Wen; Cheng Lian-Yun; Zhang Jun; Zhan Fu-Ru; Li Jun; Chen Bin; Xu Ming-Liang

    2005-01-01

    A single-particle microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering (LIBB), Chinese Academy of Sciences (CAS). The system was designed to deliver a defined number of hydrogen ions produced by a Van de Graaff accelerator, in an energy range of 2.0-3.0MeV, into an area smaller than the nuclei of individual living cells grown on thin plastic films. The beam is collimated by a borosilicate glass capillary that forms the beam-line exit. An computer integrated control program is developed to recognize the cells and to target them one by one for irradiation.Experiments for finding (capturing and recognizing) the microbeam position in the microscope imaging system and measuring the overall targeting accuracy of the facility are presented in this article. When a borosilicate glass capillary with 5μm inner diameter and 980μm length is used as the microbeam collimator, the overall targeting accuracy is that 91% aimed pit clusters are located within 2.4μm radius, and 98% are within 3.6μm radius.

  10. Design and microfabrication of a high-aspect-ratio PDMS microbeam array for parallel nanonewton force measurement and protein printing

    Science.gov (United States)

    Sasoglu, F. M.; Bohl, A. J.; Layton, B. E.

    2007-03-01

    Cell and protein mechanics has applications ranging from cellular development to tissue engineering. Techniques such as magnetic tweezers, optic tweezers and atomic force microscopy have been used to measure cell deformation forces of the order of piconewtons to nanonewtons. In this study, an array of polymeric polydimethylsiloxane (PDMS) microbeams with diameters of 10-40 µm and lengths of 118 µm was fabricated from Sylgard® with curing agent concentrations ranging from 5% to 20%. The resulting spring constants were 100-300 nN µm-1. The elastic modulus of PDMS was determined experimentally at different curing agent concentrations and found to be 346 kPa to 704 kPa in a millimeter-scale array and ~1 MPa in a microbeam array. Additionally, the microbeam array was used to print laminin for the purpose of cell adhesion. Linear and nonlinear finite element analyses are presented and compared to the closed-from solution. The highly compliant, transparent, biocompatible PDMS may offer a method for more rapid throughput in cell and protein mechanics force measurement experiments with sensitivities necessary for highly compliant structures such as axons.

  11. A Novel Integrated SET Based Inverter for Nano Power Electronic Applications

    OpenAIRE

    Negin Moezi; Daryoosh Dideban; Abbas Ketabi

    2008-01-01

    In this research an emerging field of power electronics in nanotechnology is survived. This application-based technology today is called Nano Power Electronics. It utilizes nano electronic transistors in switching applications in the range of nano power for signal shaping purposes. In recent years Single Electron Transistors are highly interested in nano electronic applications. They have got inherently fast tunneling rate, which makes them highly suitable for high-speed operation. Based on t...

  12. An Electron Beam Profile Instrument Based on FBGs

    Directory of Open Access Journals (Sweden)

    Dan Sporea

    2014-08-01

    Full Text Available Along with the dose rate and the total irradiation dose measurements, the knowledge of the beam localization and the beam profile/energy distribution in the beam are parameters of interest for charged particle accelerator installations when they are used in scientific investigations, industrial applications or medical treatments. The transverse profile of the beam, its position, its centroid location, and its focus or flatness depend on the instrument operating conditions or on the beam exit setup. Proof-of-concept of a new type of charged particle beam diagnostics based on fiber Bragg gratings (FBGs was demonstrated. Its operating principle relies on the measurement of the peak wavelength changes for an array of FBG sensors as function of the temperature following the exposure to an electron beam. Periodically, the sensor irradiation is stopped and the FBG are force cooled to a reference temperature with which the temperature influencing each sensor during beam exposure is compared. Commercially available FBGs, and FBGs written in radiation resistant optical fibers, were tested under electron beam irradiation in order to study their possible use in this application.

  13. Auto-balancing transformer based on power electronics

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dan [Electric Power Security and High Efficiency Lab, Huazhong University of Science and Technology, Wuhan 430074 (China); Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824 (United States); Mao, Chengxiong; Lu, Jiming; He, Jinping; Liu, Haibo [Electric Power Security and High Efficiency Lab, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2010-01-15

    An auto-balancing transformer based on power electronics is designed and proposed to prevent voltage or/and current unbalances arising on the primary side system from infecting the secondary side system, or in reverse. The multilevel converters and interleaving parallel connection technology are adopted in the transformer design to match the demand of power automatically balancing and high-voltage and high-power application. The operating principle is analyzed in detail and an effective control scheme is developed. To verify the new features of the proposed design, a detailed computer simulation model is established using Matlab Simulink and typical simulations are carried out. And the experimental verification is also presented. All show satisfactory results. (author)

  14. Computing environmental life of electronic products based on failure physics

    Institute of Scientific and Technical Information of China (English)

    Yongqiang Zhang; Zongchang Xu; Chunyang Hu

    2016-01-01

    In some situations, the accelerated life test on en-vironmental stress for electronic products is not easily imple-mented due to various restrictions, and thus engineers are lacking of data of the product life test. Concerning this prob-lem, environmental life of the printed circuit board (PCB) board is calculated by way of physics of failure. Influences of thermal cycle and vibration on PCB and its components are studied. Based on the analysis of force and stress between components and the PCB board in thermal cycle events and vibration events, four life computing models of pins and sol-dered dots are established. The miler damage ratio is used to calculate the accumulated damage of a pin or a soldered dot, and then the environment life of the PCB board can be de-termined by the first failed one. Finaly, an example is used to ilustrate the models and their calculations.

  15. LASER-BASED PROFILE MONITOR FOR ELECTRON BEAMS

    International Nuclear Information System (INIS)

    High performance TeV energy electron / positron colliders (LC) are the first machines to require online, non-invasive beam size monitors for micron and sub-micron for beam phase space optimization. Typical beam densities in the LC are well beyond the threshold density for single pulse melting and vaporization of any material, making conventional wire scanners ineffective. Using a finely focused, diffraction limited high power laser, it is possible to devise a sampling profile monitor that, in operation, resembles a wire scanner. Very high resolution laser-based profile monitors have been developed and tested, first at FFTB (SLAC) and later at SLC and ATF. The monitor has broad applicability and we review here the technology, application and status of ongoing research programs

  16. PROTEOTRONICS: The emerging science of protein-based electronic devices

    Science.gov (United States)

    Alfinito, Eleonora; Pousset, Jeremy; Reggiani, Lino

    2015-10-01

    Protein-mediated charge transport is of relevant importance in the design of protein based electronics and in attaining an adequate level of understanding of protein functioning. This is particularly true for the case of transmembrane proteins, like those pertaining to the G protein coupled receptors (GPCRs). These proteins are involved in a broad range of biological processes like catalysis, substance transport, etc., thus being the target of a large number of clinically used drugs. This paper briefly reviews a variety of experiments devoted to investigate charge transport in proteins and present a unified theoretical model able to relate macroscopic experimental results with the conformations of the amino acids backbone of the single protein.

  17. A Novel Diagnostics of Ultrashort Electron Bunches Based on Detection of Coherent Radiation from Bunched Electron Beam in an Undulator

    CERN Document Server

    Saldin, Evgeny L; Yurkov, Mikhail V

    2004-01-01

    We propose a new method for measurements of the longitudinal profile of 100 femtosecond electron bunches for X-ray Free Electron Lasers (XFELs). The method is based on detection of coherent undulator radiation produced by modulated electron beam. Seed optical quantum laser is used to produce exact optical replica of ultrashort electron bunches. The replica is generated in apparatus which consists of an input undulator (energy modulator), and output undulator (radiator) separated by a dispersion section. The radiation in the output undulator is excited by the electron bunch modulated at the optical wavelength and rapidly reaches a hundred-MW-level power. We then use the now-standard method of ultrashort laser pulse-shape measurement, a tandem combination of autocorrelator and spectrum (FROG -- frequency resolved optical gating) providing real-time single-shot measurements of the electron bunch structure. The big advantage of proposed technique is that it can be used to determine the slice energy spread and emi...

  18. Carbon nanotube transistor based high-frequency electronics

    Science.gov (United States)

    Schroter, Michael

    At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks. Carbon nanotube transistor based high-frequency electronics.

  19. Electrons

    International Nuclear Information System (INIS)

    Fast electrons are used to produce isotopes for studying the cooper metabolism: Cu-64 in a cyclotron and Cu-67 in a linear accelerator. Localized electrons are responsible for the chemical and physiological characteristics of the trace elements. Studied are I, Cu, Co, Zn, Mo, Mn, Fe, Se, Mg. The Cu/Mo and Cu/Zn interactions are investigated. The levels of molybdenum, sulfate and zinc in the food are analysed. The role of the electrons in free radicals is discussed. The protection action of peroxidases and super oxidases against electron dangerous effect on normal physiology is also considered. Calculation of radiation damage and radiation protection is made. (author)

  20. Development of an Electronic Claim System Based on an Integrated Electronic Health Record Platform to Guarantee Interoperability

    OpenAIRE

    Kim, Hwa Sun; Cho, Hune; Lee, In Keun

    2011-01-01

    Objectives We design and develop an electronic claim system based on an integrated electronic health record (EHR) platform. This system is designed to be used for ambulatory care by office-based physicians in the United States. This is achieved by integrating various medical standard technologies for interoperability between heterogeneous information systems. Methods The developed system serves as a simple clinical data repository, it automatically fills out the Centers for Medicare and Medic...

  1. Highly sensitive hot electron bolometer based on disordered graphene

    OpenAIRE

    Qi Han; Teng Gao; Rui Zhang; Yi Chen; Jianhui Chen; Gerui Liu; Yanfeng Zhang; Zhongfan Liu; Xiaosong Wu; Dapeng Yu

    2013-01-01

    A bolometer is a device that makes an electrical resistive response to the electromagnetic radiation resulted from a raise of temperature due to heating. The combination of the extremely weak electron-phonon interactions along with its small electron heat capacity makes graphene an ideal material for applications in ultra-fast and sensitive hot electron bolometer. However, a major issue is that the resistance of pristine graphene weakly depends on the electronic temperature. We propose using ...

  2. Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation

    Science.gov (United States)

    Tomita, Masanori; Matsumoto, Hideki; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke; Maeda, Munetoshi; Kobayashi, Yasuhiko

    2015-07-01

    In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time

  3. Inexpensive read-out for coincident electron spectroscopy with a transmission electron microscope at nanometer scale using micro channel plates and multistrip anodes

    International Nuclear Information System (INIS)

    The elemental composition of a sample at nanometer scale is determined by measurement of the characteristic energy of Auger electrons, emitted in coincidence with incoming primary electrons from a microbeam in a scanning transmission electron microscope (STEM). Single electrons are detected with position sensitive detectors, consisting of MicroChannel Plates (MCP) and MultiStrip Anodes (MSA), one for the energy of the Auger electrons (Auger-detector) and one for the energy loss of primary electrons (EELS-detector). The MSAs are sensed with LeCroy 2735DC preamplifiers. The fast readout is based on LeCroy's PCOS III system. On the detection of a coincidence (Event) energy data of Auger and EELS are combined with timing data to an Event word. Event words are stored in list mode in a VME memory module. Blocks of Event words are scanned by transputers in VME and two-dimensional energy histograms are filled using the timing information to obtain a maximal true/accidental ratio. The resulting histograms are stored on disk of a PC-386, which also controls data taking. The system is designed to handle 105 Events per second, 90% of which are accidental. In the histograms the ''true'' to ''accidental'' ratio will be 5. The dead time is 15%. ((orig.))

  4. Recent Advancements in Functionalized Paper-Based Electronics.

    Science.gov (United States)

    Lin, Yang; Gritsenko, Dmitry; Liu, Qian; Lu, Xiaonan; Xu, Jie

    2016-08-17

    Building electronic devices on ubiquitous paper substrates has recently drawn extensive attention due to its light weight, low cost, environmental friendliness, and ease of fabrication. Recently, a myriad of advancements have been made to improve the performance of paper electronics for various applications, such as basic electronic components, energy storage devices, generators, antennas, and electronic circuits. This review aims to summarize this progress and discuss different perspectives of paper electronics as well as the remaining challenges yet to be overcome in this field. Other aspects included in this review are the fundamental characteristics of paper, modification of paper with functional materials, and various methods for device fabrication.

  5. Magnetic and electronic properties of porphyrin-based molecular nanowires

    Directory of Open Access Journals (Sweden)

    Jia-Jia Zheng

    2016-01-01

    Full Text Available Using spin-polarized density functional theory calculations, we performed theoretical investigations on the electronic and magnetic properties of transition metal embedded porphyrin-based nanowires (TM-PNWs, TM = Cr, Mn, Co, Ni, Cu, and Zn. Our results indicate that Ni-PNW and Zn-PNW are nonmagnetic while the rest species are magnetic, and the magnetic moments in TM-PNWs and their corresponding isolated monomer structures are found to be the same. In addition, the spin coupling in the magnetic nanowires can be ignored leading to their degenerate AFM and FM states. These results can be ascribed to the weak intermetallic interactions because of the relatively large distances between neighbor TM atoms. Among all TM-PNW structures considered here, only Mn-PNW shows a half-metallic property while the others are predicted to be semiconducting. The present work paves a new way of obtaining ferromagnetic porphyrin-based nanowires with TM atoms distributed separately and orderly, which are expected to be good candidates for catalysts, energy storage and molecular spintronics.

  6. Magnetic and electronic properties of porphyrin-based molecular nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jia-Jia; Li, Qiao-Zhi; Dang, Jing-Shuang; Zhao, Xiang, E-mail: xzhao@mail.xjtu.edu.cn [Institute for Chemical Physics & Department of Chemistry, MOE Key Laboratory for Non-equilibrium Condensed Matter and Quantum Engineering, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Wei-Wei [Research Center for Computational Science, Institute for Molecular Science, Okazaki, Aichi 444-8585 (Japan)

    2016-01-15

    Using spin-polarized density functional theory calculations, we performed theoretical investigations on the electronic and magnetic properties of transition metal embedded porphyrin-based nanowires (TM-PNWs, TM = Cr, Mn, Co, Ni, Cu, and Zn). Our results indicate that Ni-PNW and Zn-PNW are nonmagnetic while the rest species are magnetic, and the magnetic moments in TM-PNWs and their corresponding isolated monomer structures are found to be the same. In addition, the spin coupling in the magnetic nanowires can be ignored leading to their degenerate AFM and FM states. These results can be ascribed to the weak intermetallic interactions because of the relatively large distances between neighbor TM atoms. Among all TM-PNW structures considered here, only Mn-PNW shows a half-metallic property while the others are predicted to be semiconducting. The present work paves a new way of obtaining ferromagnetic porphyrin-based nanowires with TM atoms distributed separately and orderly, which are expected to be good candidates for catalysts, energy storage and molecular spintronics.

  7. Power Electronic Transformer based Three-Phase PWM AC Drives

    Science.gov (United States)

    Basu, Kaushik

    A Transformer is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating frequency. The central idea behind a power electronic transformer (PET) also known as solid state transformer is to reduce the size of the transformer by increasing the frequency. Power electronic converters are used to change the frequency of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high frequency ac link. The windings of a high frequency transformer contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the transformer requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the frequency of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the frequency of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common

  8. Graphene Electronic Device Based Biosensors and Chemical Sensors

    Science.gov (United States)

    Jiang, Shan

    Two-dimensional layered materials, such as graphene and MoS2, are emerging as an exciting material system for a new generation of atomically thin electronic devices. With their ultrahigh surface to volume ratio and excellent electrical properties, 2D-layered materials hold the promise for the construction of a generation of chemical and biological sensors with unprecedented sensitivity. In my PhD thesis, I mainly focus on graphene based electronic biosensors and chemical sensors. In the first part of my thesis, I demonstrated the fabrication of graphene nanomesh (GNM), which is a graphene thin film with a periodic array of holes punctuated in it. The periodic holes introduce long periphery active edges that provide a high density of functional groups (e.g. carboxylic groups) to allow for covalent grafting of specific receptor molecules for chemical and biosensor applications. After covalently functionalizing the GNM with glucose oxidase, I managed to make a novel electronic sensor which can detect glucose as well as pH change. In the following part of my thesis I demonstrate the fabrication of graphene-hemin conjugate for nitric oxide detection. The non-covalent functionalization through pi-pi stacking interaction allows reliable immobilization of hemin molecules on graphene without damaging the graphene lattice to ensure the highly sensitive and specific detection of nitric oxide. The graphene-hemin nitric oxide sensor is capable of real-time monitoring of nitric oxide concentrations, which is of central importance for probing the diverse roles of nitric oxide in neurotransmission, cardiovascular systems, and immune responses. Our studies demonstrate that the graphene-hemin sensors can respond rapidly to nitric oxide in physiological environments with sub-nanomolar sensitivity. Furthermore, in vitro studies show that the graphene-hemin sensors can be used for the detection of nitric oxide released from macrophage cells and endothelial cells, demonstrating their

  9. Progress of in-air microbeam system at the Wakasa Wan Energy Research Center

    International Nuclear Information System (INIS)

    Modifications of an in-air microbeam system at the Wakasa Wan Energy Research Center designed to improve its performance are described. In the previous setup, a silicon nitride membrane (area: 1 x 1 mm2; thickness: 100 nm) was used for the beam exit window and the distance between the window and the sample was restricted to ≥1.7 mm. Due to this restriction, the beam spot size obtained using the previous setup was 13 x 13 μm2. To reduce the beam spot size, the beam exit window was replaced by a silicon nitride membrane (area: 3 (horizontal) x 2 (vertical) mm2; thickness: 200 nm). In this setup, the sample can be moved as close as 0.7 mm to the window, enabling a beam spot size of 7 x 6 μm2 to be achieved. An additional Si-PIN X-ray detector was installed to estimate the relative number of beam particles. It detects X-rays from the beam exit window. The number of the X-rays from the beam exit window (which is proportional to the number of beam particles) is used for quantitative analysis and for online monitoring of the beam current. This system has the potential to be used for simultaneous particle-induced X-ray emission (PIXE) and particle-induced gamma-ray emission (PIGE) measurements and for studying dental medicine.

  10. 'Signalling' between chromosomes in crane-fly spermatocytes studied using ultraviolet microbeam irradiation.

    Science.gov (United States)

    Wong, Raymond; Forer, Arthur

    2003-01-01

    The present article deals with signals from kinetochores in anaphase crane-fly spermatocytes: when a half-bivalent's kinetochore is irradiated with an ultraviolet microbeam during anaphase, all half-bivalents in the cell stop moving to both poles. Movement blockage is temporary, and different half-bivalent pairs resume movement at different times. Movement stoppage presumably is due to signals arising from the irradiated kinetochores and transmitted to the 'motors' of the other chromosomes. We used a second irradiation (of the interzone) to determine the path of the signal. We reasoned that if irradiation of the interzone blocked transmission of the putative signal, then those chromosomes not receiving the signal should continue to move after irradiation of a kinetochore. Interzone irradiation interfered with the signal in about 20% of the 51 cells irradiated doubly, in that chromosome(s) moving to one pole stopped while chromosome(s) moving to the other pole continued. There was a second indication that interzonal irradiation blocked the signal: in about 30% of the cells in which the kinetochore was irradiated first and interzone second, all half-bivalents resumed movement immediately after the second irradiation. PMID:14712863

  11. Distance segregation of sex chromosomes in crane-fly spermatocytes studied using laser microbeam irradiations.

    Science.gov (United States)

    Forer, Arthur; Ferraro-Gideon, Jessica; Berns, Michael

    2013-10-01

    Univalent sex chromosomes in crane-fly spermatocytes have kinetochore spindle fibres to each spindle pole (amphitelic orientation) from metaphase throughout anaphase. The univalents segregate in anaphase only after the autosomes approach the poles. As each univalent moves in anaphase, one spindle fibre shortens and the other spindle fibre elongates. To test whether the directionality of force production is fixed at anaphase, that is, whether one spindle fibre can only elongate and the other only shorten, we cut univalents in half with a laser microbeam, to create two chromatids. In both sex-chromosome metaphase and sex-chromosome anaphase, the two chromatids that were formed moved to opposite poles (to the poles to which their fibre was attached) at speeds about the same as autosomes, much faster than the usual speeds of univalent movements. Since the chromatids moved to the pole to which they were attached, independent of the direction to which the univalent as a whole was moving, the spindle fibre that normally elongates in anaphase still is able to shorten and produce force towards the pole when allowed (or caused) to do so. PMID:23315093

  12. Nuclear microbeam analysis of ICF target material made by GDP technique

    Energy Technology Data Exchange (ETDEWEB)

    Rong, C.; He, X. [Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Department of Nuclear Science and Technology, Fudan University, Shanghai 200433 (China); Meng, J., E-mail: eleanor920@163.com [Research Center of Laser Fusion, CAEP, Mianyang 621000 (China); Gao, D. [Research Center of Laser Fusion, CAEP, Mianyang 621000 (China); Zhang, Y.; Li, X.; Lyu, H.; Zhu, Y. [Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Department of Nuclear Science and Technology, Fudan University, Shanghai 200433 (China); Zheng, Y. [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); Wang, X. [Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Department of Nuclear Science and Technology, Fudan University, Shanghai 200433 (China); Shen, H., E-mail: haoshen@fudan.edu.cn [Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Department of Nuclear Science and Technology, Fudan University, Shanghai 200433 (China)

    2015-04-01

    Germanium doped carbon–hydrogen polymer (CH) by Glow Discharge Polymer (GDP) technique has become the preferred Inertial Confinement Fusion (ICF) target material. The nondestructive measurement of elements content in the ICF target has become a significant work in recent years. This paper presents the compositional and distributional results of the Germanium doped CH analysis. The Ge doped CH materials as thin film and as hollow sphere were investigated by the Rutherford Backscattering Spectroscopy (RBS) combined with the particle induced X-ray emission (PIXE) and the Elastic Recoil Detection Analysis (ERDA). The samples are thin film with 36 μm thickness and ICF target with 500–2000 μm diameter. The calibration and geometrical arrangement in the analysis of spherical target should be carefully considered in order to acquire accurate results. In the work, the uniformity of the sphere is shown and the ratio of carbon, hydrogen and germanium has been measured. The ratio values are in good agreement with the results obtained by the combustion method. In addition, the difference of the composition from thin film to hollow sphere is also discussed. This work demonstrates that nuclear microbeam analysis is an ideal method to evaluate the ICF target quality.

  13. Thin silicon strip detectors for beam monitoring in Micro-beam Radiation Therapy

    Science.gov (United States)

    Povoli, M.; Alagoz, E.; Bravin, A.; Cornelius, I.; Bräuer-Krisch, E.; Fournier, P.; Hansen, T. E.; Kok, A.; Lerch, M.; Monakhov, E.; Morse, J.; Petasecca, M.; Requardt, H.; Rosenfeld, A. B.; Röhrich, D.; Sandaker, H.; Salomé, M.; Stugu, B.

    2015-11-01

    Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any identified inadequacies for future optimisation are reported and discussed in this paper.

  14. Thin silicon strip detectors for beam monitoring in Micro-beam Radiation Therapy

    International Nuclear Information System (INIS)

    Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any identified inadequacies for future optimisation are reported and discussed in this paper

  15. Live cell imaging combined with high-energy single-ion microbeam

    Science.gov (United States)

    Guo, Na; Du, Guanghua; Liu, Wenjing; Guo, Jinlong; Wu, Ruqun; Chen, Hao; Wei, Junzhe

    2016-03-01

    DNA strand breaks can lead to cell carcinogenesis or cell death if not repaired rapidly and efficiently. An online live cell imaging system was established at the high energy microbeam facility at the Institute of Modern Physics to study early and fast cellular response to DNA damage after high linear energy transfer ion radiation. The HT1080 cells expressing XRCC1-RFP were irradiated with single high energy nickel ions, and time-lapse images of the irradiated cells were obtained online. The live cell imaging analysis shows that strand-break repair protein XRCC1 was recruited to the ion hit position within 20 s in the cells and formed bright foci in the cell nucleus. The fast recruitment of XRCC1 at the ion hits reached a maximum at about 200 s post-irradiation and then was followed by a slower release into the nucleoplasm. The measured dual-exponential kinetics of XRCC1 protein are consistent with the proposed consecutive reaction model, and the measurements obtained that the reaction rate constant of the XRCC1 recruitment to DNA strand break is 1.2 × 10-3 s-1 and the reaction rate constant of the XRCC1 release from the break-XRCC1 complex is 1.2 × 10-2 s-1.

  16. Fluid damping phenomena in a slender microbeam modelled on nonclassical theory

    Directory of Open Access Journals (Sweden)

    Belardinelli P.

    2014-01-01

    Full Text Available This work deals with the evaluation of the squeeze-film damping in an electrically-actuated microbeam considering the effects of an imposed static deflection. The model presents a reliable modelling of the mechanical behaviour by improving the classical approach with the features of the strain-gradient elasticity theory. Taking into account a correction of the electric actuation for the fringing field effects, a parametric analysis is performed. The work pays attention to evaluate the damping force on the beam surface both in small static deflection regime and near the static pull-in. The results show that the correction for the finiteness of beam edges and the high-order material parameters affect the response only at large deflections. A brief study on the static behaviour is carried out highlighting how the response is affected by the strain-gradient elasticity theory. A parametric analysis of the damping force is presented and the properties of the cut-off point are studied.

  17. Nuclear microbeam analysis of ICF target material made by GDP technique

    Science.gov (United States)

    Rong, C.; He, X.; Meng, J.; Gao, D.; Zhang, Y.; Li, X.; Lyu, H.; Zhu, Y.; Zheng, Y.; Wang, X.; Shen, H.

    2015-04-01

    Germanium doped carbon-hydrogen polymer (CH) by Glow Discharge Polymer (GDP) technique has become the preferred Inertial Confinement Fusion (ICF) target material. The nondestructive measurement of elements content in the ICF target has become a significant work in recent years. This paper presents the compositional and distributional results of the Germanium doped CH analysis. The Ge doped CH materials as thin film and as hollow sphere were investigated by the Rutherford Backscattering Spectroscopy (RBS) combined with the particle induced X-ray emission (PIXE) and the Elastic Recoil Detection Analysis (ERDA). The samples are thin film with 36 μm thickness and ICF target with 500-2000 μm diameter. The calibration and geometrical arrangement in the analysis of spherical target should be carefully considered in order to acquire accurate results. In the work, the uniformity of the sphere is shown and the ratio of carbon, hydrogen and germanium has been measured. The ratio values are in good agreement with the results obtained by the combustion method. In addition, the difference of the composition from thin film to hollow sphere is also discussed. This work demonstrates that nuclear microbeam analysis is an ideal method to evaluate the ICF target quality.

  18. Biological studies using mammalian cell lines and the current status of the microbeam irradiation system, SPICE

    Science.gov (United States)

    Konishi, T.; Ishikawa, T.; Iso, H.; Yasuda, N.; Oikawa, M.; Higuchi, Y.; Kato, T.; Hafer, K.; Kodama, K.; Hamano, T.; Suya, N.; Imaseki, H.

    2009-06-01

    The development of SPICE (single-particle irradiation system to cell), a microbeam irradiation system, has been completed at the National Institute of Radiological Sciences (NIRS). The beam size has been improved to approximately 5 μm in diameter, and the cell targeting system can irradiate up to 400-500 cells per minute. Two cell dishes have been specially designed: one a Si 3N 4 plate (2.5 mm × 2.5 mm area with 1 μm thickness) supported by a 7.5 mm × 7.5 mm frame of 200 μm thickness, and the other a Mylar film stretched by pressing with a metal ring. Both dish types may be placed on a voice coil stage equipped on the cell targeting system, which includes a fluorescent microscope and a CCD camera for capturing cell images. This microscope system captures images of dyed cell nuclei, computes the location coordinates of individual cells, and synchronizes this with the voice coil motor stage and single-particle irradiation system consisting of a scintillation counter and a beam deflector. Irradiation of selected cells with a programmable number of protons is now automatable. We employed the simultaneous detection method for visualizing the position of mammalian cells and proton traversal through CR-39 to determine whether the targeted cells are actually irradiated. An immuno-assay was also performed against γ-H2AX, to confirm the induction of DNA double-strand breaks in the target cells.

  19. Controlled Phase Gate Based on an Electron Floating on Helium

    Institute of Scientific and Technical Information of China (English)

    SHI Yan-Li; MEI Feng; YU Ya-Fei; ZHANG Zhi-Ming

    2011-01-01

    We propose a scheme to generate the controlled phase gate by using an electron floating on liquid helium. The electron is also driven by a classical laser beam and by an oscillating magnetic field. In the process, the vibration of the electron is used as the qubus to couple the energy level qubit (1D Stark-shifted hydrogen) and spin qubit Ultimately. the controlled phase gate can be generated.%@@ We propose a scheme to generate the controlled phase gate by using an electron floating on liquid helium.The electron is also driven by a classical laser beam and by an oscillating magnetic field.In the process,the vibration of the electron is used as the qubus to couple the energy level qubit(1D Stark-shifted hydrogen) and spin qubit.Ultimately,the controlled phase gate can be generated.

  20. Obstacles of XML-based electronic accounting reference

    OpenAIRE

    Juhava, Antti

    2012-01-01

    Research objectives The use of electronic accounting reference in its newest form, constructed from the viewpoint of unified practices, seems to have fallen short. Because no proper research has been conducted to depict the reasons that effect on the adoption of electronic accounting reference, this thesis aims to find answers through the following research question: What reasons hinder the adoption of electronic accounting reference for incoming invoices in Finnish companies? Researc...

  1. Electronic structure of Fe- vs. Ru-based dye molecules

    DEFF Research Database (Denmark)

    Johnson, Phillip S.; Cook, Peter L.; Zegkinoglou, Ioannis;

    2013-01-01

    In order to explore whether Ru can be replaced by inexpensive Fe in dye molecules for solar cells, the differences in the electronic structure of Fe- and Ru-based dyes are investigated by X-ray absorption spectroscopy and first-principles calculations. Molecules with the metal in a sixfold......, octahedral N cage, such as tris(bipyridines) and tris(phenanthrolines), exhibit a systematic downward shift of the N 1s-to-π* transition when Ru is replaced by Fe. This shift is explained by an extra transfer of negative charge from the metal to the N ligands in the case of Fe, which reduces the binding...... energy of the N 1s core level. The C 1s-to-π* transitions show the opposite trend, with an increase in the transition energy when replacing Ru by Fe. Molecules with the metal in a fourfold, planar N cage (porphyrins) exhibit a more complex behavior due to a subtle competition between the crystal field...

  2. Digital waterway construction based on inland electronic navigation chart

    Science.gov (United States)

    Wang, Xue; Pan, Junfeng; Zhu, Weiwei

    2015-12-01

    With advantages of large capacity, long distance, low energy consumption, low cost, less land occupation and light pollution, inland waterway transportation becomes one of the most important constituents of the comprehensive transportation system and comprehensive water resources utilization in China. As one of "three elements" of navigation, waterway is the important basis for the development of water transportation and plays a key supporting role in shipping economic. The paper discuss how to realize the informatization and digitization of waterway management based on constructing an integrated system of standard inland electronic navigation chart production, waterway maintenance, navigation mark remote sensing and control, ship dynamic management, and water level remote sensing and report, which can also be the foundation of the intelligent waterway construction. Digital waterway construction is an information project and also has a practical meaning for waterway. It can not only meet the growing high assurance and security requirements for waterway, but also play a significant advantage in improving transport efficiency, reducing costs, promoting energy conservation and so on. This study lays a solid foundation on realizing intelligent waterway and building a smooth, efficient, safe, green modern inland waterway system, and must be considered as an unavoidable problem for the coordinated development between "low carbon" transportation and social economic.

  3. Inter-base Electronic Coupling for transport through DNA

    CERN Document Server

    Anantram, H M M P

    2005-01-01

    We develop a new approach to derive single state tight binding (SSTB) model for electron transport in the vicinity of valence-conduction bands of poly(G)-poly(C) and poly(A)-poly(T) DNA. The SSTB parameters are derived from {\\it first principles} and are used to model charge transport through finite length DNA. We investigate the rigor of reducing the full DNA Hamiltonian to SSTB model to represent charge transport in the vicinity of valence-conduction band. While the transmission coefficient spectrum is preserved, its position shifts in energy. Thymine is poorly represented and its peak height is substantially reduced. This is attributed to the abstraction of the HOMO-LUMO coupling to other eigen-states in the nearest neighbor DNA bases, and can be corrected within $2^{nd}$ order time independent perturbation theory. Inter-strand charge transport has also been analyzed and it is found that hopping to the nearest neighbor in the complementary strand is the most important process except in the valence band of ...

  4. Optical sensor array platform based on polymer electronic devices

    Science.gov (United States)

    Koetse, Marc M.; Rensing, Peter A.; Sharpe, Ruben B. A.; van Heck, Gert T.; Allard, Bart A. M.; Meulendijks, Nicole N. M. M.; Kruijt, Peter G. M.; Tijdink, Marcel W. W. J.; De Zwart, René M.; Houben, René J.; Enting, Erik; van Veen, Sjaak J. J. F.; Schoo, Herman F. M.

    2007-10-01

    Monitoring of personal wellbeing and optimizing human performance are areas where sensors have only begun to be used. One of the reasons for this is the specific demands that these application areas put on the underlying technology and system properties. In many cases these sensors will be integrated in clothing, be worn on the skin, or may even be placed inside the body. This implies that flexibility and wearability of the systems is essential for their success. Devices based on polymer semiconductors allow for these demands since they can be fabricated with thin film technology. The use of thin film device technology allows for the fabrication of very thin sensors (e.g. integrated in food product packaging), flexible or bendable sensors in wearables, large area/distributed sensors, and intrinsically low-cost applications in disposable products. With thin film device technology a high level of integration can be achieved with parts that analyze signals, process and store data, and interact over a network. Integration of all these functions will inherently lead to better cost/performance ratios, especially if printing and other standard polymer technology such as high precision moulding is applied for the fabrication. In this paper we present an optical transmission sensor array based on polymer semiconductor devices made by thin film technology. The organic devices, light emitting diodes, photodiodes and selective medium chip, are integrated with classic electronic components. Together they form a versatile sensor platform that allows for the quantitative measurement of 100 channels and communicates wireless with a computer. The emphasis is given to the sensor principle, the design, fabrication technology and integration of the thin film devices.

  5. Electronic nanobiosensors based on two-dimensional materials

    Science.gov (United States)

    Ping, Jinglei

    Atomically-thick two-dimensional (2D) nanomaterials have tremendous potential to be applied as transduction elements in biosensors and bioelectronics. We developed scalable methods for synthesis and large-area transfer of two-dimensional nanomaterials, particularly graphene and metal dichalcogenides (so called ``MX2'' materials). We also developed versatile fabrication methods for large arrays of field-effect transistors (FETs) and micro-electrodes with these nanomaterials based on either conventional photolithography or innovative approaches that minimize contamination of the 2D layer. By functionalizing the FETs with a computationally redesigned water-soluble mu-opioid receptor, we created selective and sensitive biosensors suitable for detection of the drug target naltrexone and the neuropeptide enkephalin at pg/mL concentrations. We also constructed DNA-functionalized biosensors and nano-particle decorated biosensors by applying related bio-nano integration techniques. Our methodology paves the way for multiplexed nanosensor arrays with all-electronic readout suitable for inexpensive point-of-care diagnostics, drug-development and biomedical research. With graphene field-effect transistors, we investigated the graphene/solution interface and developed a quantitative model for the effect of ionic screening on the graphene carrier density based on theories of the electric double layer. Finally, we have developed a technique for measuring low-level Faradaic charge-transfer current (fA) across the graphene/solution interface via real-time charge monitoring of graphene microelectrodes in ionic solution. This technique enables the development of flexible and transparent pH sensors that are promising for in vivo applications. The author acknowledges the support from the Defense Advanced Research Projects Agency (DARPA) and the U. S. Army Research Office under Grant Number W911NF1010093.

  6. An Analysis of Electronic Products’ Advertisements Based onthe Cooperative Principles

    Institute of Scientific and Technical Information of China (English)

    周亚林

    2015-01-01

    In moderntimes,more and more electronic products appear.Advertisements as an important way to promotethe products are applied by more and more businessmen.Many advertisements violate the Cooperative Principles which is proposed by the philosopher Paul Grice.This paper attempts to analyze the violations of cooperative principles in English electronic products’ advertisements.

  7. Graphene-Based Chemical Vapor Sensors for Electronic Nose Applications

    Science.gov (United States)

    Nallon, Eric C.

    An electronic nose (e-nose) is a biologically inspired device designed to mimic the operation of the olfactory system. The e-nose utilizes a chemical sensor array consisting of broadly responsive vapor sensors, whose combined response produces a unique pattern for a given compound or mixture. The sensor array is inspired by the biological function of the receptor neurons found in the human olfactory system, which are inherently cross-reactive and respond to many different compounds. The use of an e-nose is an attractive approach to predict unknown odors and is used in many fields for quantitative and qualitative analysis. If properly designed, an e-nose has the potential to adapt to new odors it was not originally designed for through laboratory training and algorithm updates. This would eliminate the lengthy and costly R&D costs associated with materiel and product development. Although e-nose technology has been around for over two decades, much research is still being undertaken in order to find new and more diverse types of sensors. Graphene is a single-layer, 2D material comprised of carbon atoms arranged in a hexagonal lattice, with extraordinary electrical, mechanical, thermal and optical properties due to its 2D, sp2-bonded structure. Graphene has much potential as a chemical sensing material due to its 2D structure, which provides a surface entirely exposed to its surrounding environment. In this configuration, every carbon atom in graphene is a surface atom, providing the greatest possible surface area per unit volume, so that electron transport is highly sensitive to adsorbed molecular species. Graphene has gained much attention since its discovery in 2004, but has not been realized in many commercial electronics. It has the potential to be a revolutionary material for use in chemical sensors due to its excellent conductivity, large surface area, low noise, and versatile surface for functionalization. In this work, graphene is incorporated into a

  8. HPS Electronic Ballast Based on CIC-CPPFC Technique

    Institute of Scientific and Technical Information of China (English)

    王卫; 苏勤; 高国安

    2002-01-01

    Investigates the application of CIC-CPPFC techniques to high-pressure sodium(HPS) lamp electronic ballast. In order to ensure a unity power factor, different power electronic ballasts are studied by PSpice simulation. A dynamic model of HPS lamp with simple and accurate features is proposed for further study of characteristics. Experimental results verify the feasibility of HPS lamp operating at high frequency. It is shown that the presented electronic ballast has 0.99 power factor and 9% total harmonic distortion(THD).

  9. Electronic structure of nitride-based quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Winkelnkemper, Momme

    2008-11-07

    In the present work the electronic and optical properties of In{sub x}Ga{sub 1-x}N/GaN and GaN/AlN QDs are studied by means of eight-band k.p theory. Experimental results are interpreted in detail using the theoretical results. The k.p model for the QD electronicstructure calculations accounts for strain, piezo- and pyroelectric effects, spin-orbit and crystal-field splitting, and is implemented for arbitrarily shaped QDs on a finite differences grid. Few-particle corrections are included using the self-consistent Hartree method. Band parameters for the wurtzite and zinc-blende phases of GaN, AlN, and InN are derived from first-principle G{sub 0}W{sub 0} band-structure calculations. Reliable values are also provided for parameters that have not been determined experimentally yet. The electronic properties of nitride QDs are dominated by the large built-in piezo- and pyroelectric fields, which lead to a pronounced red-shift of excitonic transition energies and extremely long radiative lifetimes in large GaN/AlN QDs. In In{sub x}Ga{sub 1-x}N/GaN QDs these fields induce a pronounced dependence of the radiative excitonic lifetimes on the exact QD shape and composition. It is demonstrated that the resulting variations of the radiative lifetimes in an inhomogeneous QD ensemble are the origin of the multi-exponential luminescence decay frequently observed in time-resolved ensemble measurements on In{sub x}Ga{sub 1-x}N/GaN QDs. A polarization mechanism in nitride QDs based on strain-induced valence-band mixing effects is discovered. Due to the valence-band structure of wurtzite group-III nitrides and the specific strain situation in c-plane QDs, the confined hole states are formed predominantly by the two highest valence bands. In particular, the hole ground state (h{sub 0} {identical_to} h{sub A}) is formed by the A band, and the first excited hole state (h{sub 1} {identical_to} h{sub B}) by the B band. It is shown that the interband transitions involving h{sub A} or h

  10. ID-Based Fair Off-Line Electronic Cash System with Multiple Banks

    Institute of Scientific and Technical Information of China (English)

    Chang-Ji Wang; Yong Tang; Qing Li

    2007-01-01

    ID-based public key cryptography (ID-PKC) has many advantages over certificate-based public key cryptog-raphy (CA-PKC), and has drawn researchers’ extensive attention in recent years. However, the existing electronic cash schemes are constructed under CA-PKC, and there seems no electronic cash scheme under ID-PKC up to now to the best of our knowledge. It is important to study how to construct electronic cash schemes based on ID-PKC from views on both practical perspective and pure research issue. In this paper, we present a simpler and provably secure ID-based restrictive partially blind signature (RPBS), and then propose an ID-based fair off-line electronic cash (ID-FOLC) scheme with multiple banks based on the proposed ID-based RPBS. The proposed ID-FOLC scheme with multiple banks is more efficient than existing electronic cash schemes with multiple banks based on group blind signature.

  11. Tuning the Electron Acceptor in Phthalocyanine-Based Electron Donor-Acceptor Conjugates.

    Science.gov (United States)

    Sekita, Michael; Jiménez, Ángel J; Marcos, M Luisa; Caballero, Esmeralda; Rodríguez-Morgade, M Salomé; Guldi, Dirk M; Torres, Tomás

    2015-12-21

    Zinc phthalocyanines (ZnPc) have been attached to the peri-position of a perylenemonoimide (PMI) and a perylenemonoanhydride (PMA), affording electron donor-acceptor conjugates 1 and 2, respectively. In addition, a perylene-monoimide-monoanhydride (PMIMA) has been connected to a ZnPc through its imido position to yield the ZnPc-PMIMA conjugate 10. The three conjugates have been studied for photoinduced electron transfer. For ZnPc-PMIMA 10, electron transfer occurs upon both ZnPc and PMIMA excitation, giving rise to a long-lived (340 ps) charge-separated state. For ZnPc-PMI 1 and ZnPc-PMA 2, stabilization of the radical ion pair states by using polar media is necessary. In THF, photoexcitation of either ZnPc or PMI/PMA produces charge-separated states with lifetimes of 375 and 163 ps, respectively. PMID:26593778

  12. A Carbon Nanotube Electron Source Based Ionization Vacuum Gauge

    Energy Technology Data Exchange (ETDEWEB)

    Changkun Dong; Ganapati Myneni

    2003-10-01

    The results of fabrication and performance of an ionization vacuum gauge using a carbon nanotube (CNT) electron source are presented. The electron source was constructed with multi-wall nanotubes (MWNT), which were grown using thermal chemical vapor deposition (CVD) process. The electron emission of the source was stable in vacuum pressure up to 10-7 Torr, which is better than the metal field emitters. The measurement linearity of the gauge was better than {+-}10% from 10-6 to 10-10 Torr. The gauge sensitivity of 4 Torr-1 was achieved under 50 {micro}A electron emission in nitrogen. The gauge is expected to find applications in vacuum measurements from 10-7 Torr to below 10-11 Torr.

  13. Optical polarimeter based on Fourier analysis and electronic control

    International Nuclear Information System (INIS)

    In this paper, we show the design and implementation of an optical polarimeter using electronic control and the Fourier analysis. The polarimeter prototype will be used as a main tool for the students of the Universidad Popular del Cesar that belong to the following university programs: Electronics engineering (optoelectronics area), Math and Physics degree and the Master in Physics Sciences, in order to learning the theory and experimental aspects of the state of optical polarization via the Stokes vector measurement. Using the electronic polarimeter proposed in this paper, the students will be able to observe (in an optical bench) and understand the different interactions of the states of optical polarization when the optical waves pass through to the polarizers and retarder waves plates. The electronic polarimeter has a software that captures the optical intensity measurement and evaluates the Stokes vector. (Author)

  14. Sturmian bases for two-electron systems in hyperspherical coordinates

    CERN Document Server

    Abdouraman, A; Hamido, A; Mota-Furtado, F; O'Mahony, P F; Mitnik, D; Gasaneo, G; Piraux, B

    2016-01-01

    We give a detailed account of an $\\it{ab}$ $\\it{initio}$ spectral approach for the calculation of energy spectra of two active electron atoms in a system of hyperspherical coordinates. In this system of coordinates, the Hamiltonian has the same structure as the one of atomic hydrogen with the Coulomb potential expressed in terms of a hyperradius and the nuclear charge replaced by an angle dependent effective charge. The simplest spectral approach consists in expanding the hyperangular wave function in a basis of hyperspherical harmonics. This expansion however, is known to be very slowly converging. Instead, we introduce new hyperangular sturmian functions. These functions do not have an analytical expression but they treat the first term of the multipole expansion of the electron-electron interaction potential, namely the radial electron correlation, exactly. The properties of these new functions are discussed in detail. For the basis functions of the hyperradius, several choices are possible. In the present...

  15. Designing Electronic Markets for Defeasible-based Contractual Agents

    OpenAIRE

    Groza, Adrian

    2013-01-01

    The design of punishment policies applied to specific domains linking agents actions to material penalties is an open research issue. The proposed framework applies principles of contract law to set penalties: expectation damages, opportunity cost, reliance damages, and party design remedies. In order to decide which remedy provides maximum welfare within an electronic market, a simulation environment called DEMCA (Designing Electronic Markets for Contractual Agents) was developed. Knowledge ...

  16. Electronic counterfeit detection based on the measurement of electromagnetic fingerprint

    OpenAIRE

    Huang, He; H. Huang; Boyer, Alexandre; Boyer, A; Ben Dhia, Sonia

    2015-01-01

    International audience Counterfeit integrated circuits become a big challenge for the whole electronic industry. The use of electronic counterfeits can cause reduced performance of circuits, or failure of the whole system. New efficient approaches of counterfeit device detection are always required. Since the electromagnetic emission level of integrated devices depends on various circuit parameters like technology, manufacturing and aging, the electromagnetic emission measurement could be ...

  17. Ion beam induced charge collection (IBICC) from integrated circuit test structures using a 10 MeV carbon microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Guo, B.N.; Bouanani, M.E.; Duggan, J.L.; McDaniel, F.D. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, Denton, Texas 76203 (United States); Doyle, B.L.; Walsh, D.S. [Ion Beam Materials Research Laboratory, Sandia National Laboratories, MS 1056, PO Box 5800, Albuquerque, New Mexico 87185 (United States)] Aton, T.J. [Silicon Technology Development, Texas Instruments Inc., PO Box 650311, MS 3704, Dallas, Texas 75265 (United States)

    1999-06-01

    As feature sizes of Integrated Circuits (ICs) continue to shrink, the sensitivity of these devices, particularly SRAMs and DRAMs, to natural radiation is increasing. In this paper, the Ion Beam Induced Charge Collection (IBICC) technique is utilized to simulate neutron-induced Si recoil effects in ICs. The IBICC measurements, conducted at the Sandia National Laboratories, employed a 10 MeV carbon microbeam with 1{mu}m diameter spot to scan test structures on specifically designed ICs. With the aid of IC layout information, an analysis of the charge collection efficiency from different test areas is presented. {copyright} {ital 1999 American Institute of Physics.}

  18. Production of excited electrons at TESLA and CLIC based $e\\gamma$ colliders

    CERN Document Server

    Aydin, Z Z; Kirca, Z

    2003-01-01

    We analyze the potential of TESLA and CLIC based electron-photon colliders to search for excited spin-1/2 electrons. The production of excited electrons in the resonance channel through the electron-photon collision and their subsequent decays to leptons and electroweak gauge bosons are investigated. We study in detail the three signal channels of excited electrons and the corresponding backgrounds through the reactions e gamma --> e gamma, e gamma --> eZ and e gamma --> nu W. Excited electrons can be discovered with the masses up to about 90% of the available collider energy.

  19. Nonlinear dynamics of an electrically actuated imperfect microbeam resonator: Experimental investigation and reduced-order modeling

    KAUST Repository

    Ruzziconi, Laura

    2013-06-10

    We present a study of the dynamic behavior of a microelectromechanical systems (MEMS) device consisting of an imperfect clamped-clamped microbeam subjected to electrostatic and electrodynamic actuation. Our objective is to develop a theoretical analysis, which is able to describe and predict all the main relevant aspects of the experimental response. Extensive experimental investigation is conducted, where the main imperfections coming from microfabrication are detected, the first four experimental natural frequencies are identified and the nonlinear dynamics are explored at increasing values of electrodynamic excitation, in a neighborhood of the first symmetric resonance. Several backward and forward frequency sweeps are acquired. The nonlinear behavior is highlighted, which includes ranges of multistability, where the nonresonant and the resonant branch coexist, and intervals where superharmonic resonances are clearly visible. Numerical simulations are performed. Initially, two single mode reduced-order models are considered. One is generated via the Galerkin technique, and the other one via the combined use of the Ritz method and the Padé approximation. Both of them are able to provide a satisfactory agreement with the experimental data. This occurs not only at low values of electrodynamic excitation, but also at higher ones. Their computational efficiency is discussed in detail, since this is an essential aspect for systematic local and global simulations. Finally, the theoretical analysis is further improved and a two-degree-of-freedom reduced-order model is developed, which is also capable of capturing the measured second symmetric superharmonic resonance. Despite the apparent simplicity, it is shown that all the proposed reduced-order models are able to describe the experimental complex nonlinear dynamics of the device accurately and properly, which validates the proposed theoretical approach. © 2013 IOP Publishing Ltd.

  20. Application of imaging plate to micro-beam X-ray diffraction

    International Nuclear Information System (INIS)

    A new type of integrating area detector system with high sensitivity and high spatial resolution was recently developed for diagnostic radiography. In this detector system, a two dimensional X-ray image is temporarily stored as a distribution of F-centers in a photostimulable phosphor screen called the imaging plate (IP). The image in the IP is then read out by measuring the intensity of fluorescence which is stimulated by a focused He-Ne laser beam scanning the surface of the phosphor screen. The residual X-ray image in the IP can be erased simply by exposing it to a large dose of visible light and the IP can be used repeatedly. The detector has 100% detective quantum efficiency for 0-20 keV X-ray, a spatial resolution better than 0.15mm(fwhm), a dynamic range of 105 and no counting rate limitation. The exposure time can be shorten to 1/20-1/60 in comparison with the use of the X-ray film. In this study, we examined the possibility of the IP for the X-ray studies on the mechanical behaviour of materials by using the back-reflection X-ray technique. An exposure time of more than 30 minutes would be required for a conventional high sensitivity X-ray film in the case of αFe(211) diffraction by Cr-Kα X-rays. When the imaging plates were used in place of the film under the same X-ray condition, we could obtain visually similar patterns by exposing the time of less than 90 seconds. These diffraction patterns can be precisely analyzed with the help of the image processing analyzer. We conclude that this detector system is usable in almost the same way as an X-ray film. Especially, this will be more powerful means in the field of micro-beam X-ray diffraction. (author)

  1. Modification of anisotropic plasma diffusion via auxiliary electrons emitted by a carbon nanotubes-based electron gun in an electron cyclotron resonance ion source.

    Science.gov (United States)

    Malferrari, L; Odorici, F; Veronese, G P; Rizzoli, R; Mascali, D; Celona, L; Gammino, S; Castro, G; Miracoli, R; Serafino, T

    2012-02-01

    The diffusion mechanism in magnetized plasmas is a largely debated issue. A short circuit model was proposed by Simon, assuming fluxes of lost particles along the axial (electrons) and radial (ions) directions which can be compensated, to preserve the quasi-neutrality, by currents flowing throughout the conducting plasma chamber walls. We hereby propose a new method to modify Simon's currents via electrons injected by a carbon nanotubes-based electron gun. We found this improves the source performances, increasing the output current for several charge states. The method is especially sensitive to the pumping frequency. Output currents for given charge states, at different auxiliary electron currents, will be reported in the paper and the influence of the frequency tuning on the compensation mechanism will be discussed.

  2. Modification of anisotropic plasma diffusion via auxiliary electrons emitted by a carbon nanotubes-based electron gun in an electron cyclotron resonance ion source.

    Science.gov (United States)

    Malferrari, L; Odorici, F; Veronese, G P; Rizzoli, R; Mascali, D; Celona, L; Gammino, S; Castro, G; Miracoli, R; Serafino, T

    2012-02-01

    The diffusion mechanism in magnetized plasmas is a largely debated issue. A short circuit model was proposed by Simon, assuming fluxes of lost particles along the axial (electrons) and radial (ions) directions which can be compensated, to preserve the quasi-neutrality, by currents flowing throughout the conducting plasma chamber walls. We hereby propose a new method to modify Simon's currents via electrons injected by a carbon nanotubes-based electron gun. We found this improves the source performances, increasing the output current for several charge states. The method is especially sensitive to the pumping frequency. Output currents for given charge states, at different auxiliary electron currents, will be reported in the paper and the influence of the frequency tuning on the compensation mechanism will be discussed. PMID:22380190

  3. Reconstruction of F2 layer peak electron density based on operational vertical total electron content maps

    Directory of Open Access Journals (Sweden)

    T. Gerzen

    2013-07-01

    Full Text Available Electron density is the major determining parameter of the ionosphere. Especially the maximum electron density of the F2 layer in the ionosphere, NmF2, is of particular interest with regard to the HF radio communication applications as well as for characterizing the ionosphere. In this paper we present a new method to generate global maps of NmF2. The main principle behind this approach is to use the information about the current state of the ionosphere included in global total electron content (TEC maps as well as the relationship between total electron content, equivalent slab thickness and F2 layer peak density. Modeling of slab thickness is an interim step in our reconstruction approach. Thus, results showing the diurnal and seasonal variations and effects of solar activity on the modeled slab thickness values are given. In addition a comparison of the reconstructed NmF2 maps with measurements from several ionosonde stations as well as with the global NmF2 model NPDM is presented. Since 2011 the described method has been used at DLR Neustrelitz to generate NmF2 maps as operational service. These maps are freely available via the Space Weather Application Center Ionosphere SWACI (http://swaciweb.dlr.de.

  4. Numerical Modeling of Microbial Fuel Cell Based on Redox Electron Mediator

    Institute of Scientific and Technical Information of China (English)

    Nanqi Ren

    2015-01-01

    To investigate the behavior of redox electron mediator and its impact to power generation of microbial fuel cell ( MFC ) , this study carries out the numerical modeling of a typical two⁃chamber MFC based on assumption of interfacial electron transfer via redox electron mediator and acetate as sole electron donor. The model simulates the development of cell voltage, current, substrate concentration, redox electron mediator concentration, polarization and power density output under defined conditions. The results demonstrate that the developed models can fit the experimental results well on a qualitative basis, and concentration of electron reduced mediator plays a dominant role in electron transfer process, and the mass transfer may constitute the limiting step when its concentration is at a relatively low level. This study not only provides a better understanding of electron redox mediator behavior during power generation, but also suggests a strategy to improve electron transfer in the anode of MFC.

  5. A modularized electronic payment system for agent-based e-commerce

    OpenAIRE

    Guan, Su; Tan, SL; Hua, F.

    2004-01-01

    With the explosive growth of the Internet, electronic-commerce (e-commerce) is an increasingly important segment of commercial activities on the web. The Secure Agent Fabrication, Evolution & Roaming (SAFER) architecture was proposed to further facilitate e-commerce using agent technology. In this paper, the electronic payment aspect of SAFER will be explored. The Secure Electronic Transaction (SET) protocol and E-Cash were selected as the bases for the electronic payment system implementatio...

  6. Highly sensitive hot electron bolometer based on disordered graphene.

    Science.gov (United States)

    Han, Qi; Gao, Teng; Zhang, Rui; Chen, Yi; Chen, Jianhui; Liu, Gerui; Zhang, Yanfeng; Liu, Zhongfan; Wu, Xiaosong; Yu, Dapeng

    2013-01-01

    A bolometer is a device that makes an electrical resistive response to the electromagnetic radiation resulted from a raise of temperature due to heating. The combination of the extremely weak electron-phonon interactions along with its small electron heat capacity makes graphene an ideal material for applications in ultra-fast and sensitive hot electron bolometer. However, a major issue is that the resistance of pristine graphene weakly depends on the electronic temperature. We propose using disordered graphene to obtain a strongly temperature dependent resistance. The measured electrical responsivity of the disordered graphene bolometer reaches 6 × 10(6) V/W at 1.5 K, corresponding to an optical responsivity of 1.6 × 10(5) V/W. The deduced electrical noise equivalent power is 1.2 fW/√Hz, corresponding to the optical noise equivalent power of 44 fW/√Hz. The minimal device structure and no requirement for high mobility graphene make a step forward towards the applications of graphene hot electron bolometers. PMID:24346418

  7. Multifunctional, flexible electronic systems based on engineered nanostructured materials

    Science.gov (United States)

    Ko, Hyunhyub; Kapadia, Rehan; Takei, Kuniharu; Takahashi, Toshitake; Zhang, Xiaobo; Javey, Ali

    2012-08-01

    The development of flexible electronic systems has been extensively researched in recent years, with the goal of expanding the potential scope and market of modern electronic devices in the areas of computation, communications, displays, sensing and energy. Uniquely, the use of soft polymeric substrates enables the incorporation of advanced features beyond mechanical bendability and stretchability. In this paper, we describe several functionalities which can be achieved using engineered nanostructured materials. In particular, reversible binding, self-cleaning, antireflective and shape-reconfigurable properties are introduced for the realization of multifunctional, flexible electronic devices. Examples of flexible systems capable of spatial mapping and/or responding to external stimuli are also presented as a new class of user-interactive devices.

  8. Electronic counterfeit detection based on the measurement of electromagnetic fingerprint Electronic counterfeit detection based on the measurement of electromagnetic fingerprint

    OpenAIRE

    H. Huang; Huang, He; Boyer, A; Boyer, Alexandre; Ben Dhia, Sonia

    2015-01-01

    International audience Counterfeit integrated circuits become a big challenge for the whole electronic industry. The use of electronic counterfeits can cause reduced performance of circuits, or failure of the whole system. New efficient approaches of counterfeit device detection are always required. Since the electromagnetic emission level of integrated devices depends on various circuit parameters like technology, manufacturing and aging, the electromagnetic emission measurement could be ...

  9. Electronic Warfare Simulation-based on Service Oriented Architecture

    Directory of Open Access Journals (Sweden)

    J. Nanda Kishore

    2012-07-01

    Full Text Available The realisation of service oriented architecture (SOA is embodied in the accomplishments of various simulation applicable functions in the form of service encapsulation and the interconnection and interoperation of services. In this paper, an electronic warfare (EW simulation is structured to SOA and achieved the effect of dynamic sharing and reusability. As a proof of concept, a radar electronic support (ES simulator, which intercepts and classifies radar signals is designed and explained in this paper.Defence Science Journal, 2012, 62(4, pp.219-222, DOI:http://dx.doi.org/10.14429/dsj.62.929

  10. Low-kilovolt coherent electron diffractive imaging instrument based on a single-atom electron source

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chun-Yueh [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Chang, Wei-Tse; Chen, Yi-Sheng; Hwu, En-Te; Chang, Chia-Seng; Hwang, Ing-Shouh, E-mail: ishwang@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Hsu, Wei-Hao [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2016-03-15

    In this work, a transmission-type, low-kilovolt coherent electron diffractive imaging instrument was constructed. It comprised a single-atom field emitter, a triple-element electrostatic lens, a sample holder, and a retractable delay line detector to record the diffraction patterns at different positions behind the sample. It was designed to image materials thinner than 3 nm. The authors analyzed the asymmetric triple-element electrostatic lens for focusing the electron beams and achieved a focused beam spot of 87 nm on the sample plane at the electron energy of 2 kV. High-angle coherent diffraction patterns of a suspended graphene sample corresponding to (0.62 Å){sup −1} were recorded. This work demonstrated the potential of coherent diffractive imaging of thin two-dimensional materials, biological molecules, and nano-objects at a voltage between 1 and 10 kV. The ultimate goal of this instrument is to achieve atomic resolution of these materials with high contrast and little radiation damage.

  11. Assessment of Proton Microbeam Analysis of 11B for Quantitative Microdistribution Analysis of Boronated Neutron Capture Agent Analogs in Biological Tissues

    Energy Technology Data Exchange (ETDEWEB)

    Bench, G; Grant, P G; Ueda, D L; Autry-Conwell, S A; Hou, Y; Boggan, J E

    2002-12-04

    Purpose: To assess the {sup 11}B(p, {alpha}){sup 8}Be* nuclear reaction for quantitatively mapping the in-vivo sub-cellular distribution of boron within gliosarcoma tumors treated with boronated neutron capture therapy agent (NCTA) analogs. Materials and Methods: Intracranial tumors were produced in Fisher 344 rats using a 9L gliosarcoma model. Fourteen days later, the majority of rats were treated with f-boronophenylalanine and sacrificed 30 or 180 minutes after intravenous injection. Freeze dried tumor cryosections were imaged using the {sup 11}B(p, {alpha}){sup 8}Be* nuclear reaction and proton microbeams obtained from the nuclear microprobe at Lawrence Livermore National Laboratory. Results/Discussion: With{sup 11}B(p, {alpha}){sup 8}Be* analysis, {sup 11}B distributions within cells can be quantitatively imaged with spatial resolutions down to 1.5 {micro}m, minimum detection limits of 0.8 mg/kg and acquisition times of several hours. These capabilities offer advantages over alpha track autoradiography, electron energy loss spectroscopy and secondary ion mass spectrometry (SIMS) for 'B quantitation in tissues. However, the spatial resolution, multi-isotope capability and analysis times achieved with SIMS are superior to those achieved with {sup 11}B(p, {alpha}){sup 8}Be* analysis. Conclusions: When accuracy in quantitation is crucial, the assessing the microdistribution of {sup 11}B. {sup 11}B(p, {alpha}){sup 8}Be* reaction is well suited for Otherwise, SIMS may well be better suited to image the microdistribution of boron associated with NCTAs in biological tissues.

  12. Vacancy-related defects in n-type Si implanted with a rarefied microbeam of accelerated heavy ions in the MeV range

    Science.gov (United States)

    Capan, I.; Pastuović, Ž.; Siegele, R.; Jaćimović, R.

    2016-04-01

    Deep level transient spectroscopy (DLTS) has been used to study vacancy-related defects formed in bulk n-type Czochralski-grown silicon after implantation of accelerated heavy ions: 6.5 MeV O, 10.5 MeV Si, 10.5 MeV Ge, and 11 MeV Er in the single ion regime with fluences from 109 cm-2 to 1010 cm-2 and a direct comparison made with defects formed in the same material irradiated with 0.7 MeV fast neutron fluences up to 1012 cm-2. A scanning ion microprobe was used as the ion implantation tool of n-Cz:Si samples prepared as Schottky diodes, while the ion beam induced current (IBIC) technique was utilized for direct ion counting. The single acceptor state of the divacancy V2(-/0) is the most prominent defect state observed in DLTS spectra of n-CZ:Si samples implanted by selected ions and the sample irradiated by neutrons. The complete suppression of the DLTS signal related to the double acceptor state of divacancy, V2(=/-) has been observed in all samples irradiated by ions and neutrons. Moreover, the DLTS peak associated with formation of the vacancy-oxygen complex VO in the neutron irradiated sample was also completely suppressed in DLTS spectra of samples implanted with the raster scanned ion microbeam. The reason for such behaviour is twofold, (i) the local depletion of the carrier concentration in the highly disordered regions, and (ii) the effect of the microprobe-assisted single ion implantation. The activation energy for electron emission for states assigned to the V2(-/0) defect formed in samples implanted by single ions follows the Meyer-Neldel rule. An increase of the activation energy is strongly correlated with increasing ion mass.

  13. The Electron Scattering Data Base - Is it Fit for Purpose ?

    International Nuclear Information System (INIS)

    Electron induced reactions in both the gaseous and condensed phases initiate and drive many of the basic physical and chemical processes in science and technology with applications from industrial plasmas to radiation damage in living tissue. For example, in contrast to previous hypotheses, collisions of very low energy secondary electrons with the components of DNA molecules (or to the water around them) has been shown to be a crucial process in inducing radiation damage in the DNA of living systems. Understanding electron interactions with larger biomolecules is therefore providing new insights to radiation damage and thence the development of new, alternative radiotherapies. In the technological field electron induced reactions underpin most of the multibillion dollar modern semiconductor industry since it is those reactive fragments produced by electron impact of etchant gases that react directly with the silicon substrate. Studies on electron scattering from molecules capable of improving the etch rate of surfaces are leading to development of new (environmentally cleaner) plasma technologies. Electron induced processes are also of extraordinary importance for determination of structure and chemical reactivity of species adsorbed on surfaces. Such research and technology is intricately linked to our knowledge of the key interactions between electosn and atoms and molecules and thus we require a database for characterizing electron interactions with atomic and molecular species. However the compilation of the electron collsion data required is rarely a coherent, planned research programme instead it is a parasitic process. Indeed today it is rare for researchers to be funded to measure fundamental collision processes since these are no longer regarded in themselves as 'cutting edge' research rather the field has developed to explore more exotic phenomena such as cold atoms; nanotechnology and chemical control. The fundamental research community, the providers

  14. Electronic states of emodin and its conjugate base

    DEFF Research Database (Denmark)

    Nguyen, Son Chi; Hansen, Bjarke Knud Vilster; Hoffmann, Søren Vrønning;

    2008-01-01

    the assignment of at least 7 excited electronic states in the region 15000 - 50000 cm-1 for each species. A recent assignment of the absorption spectrum of E to a superposition of contributions from 9,10- and 1,10-anthraquinoid tautomeric forms was not supported by the results of the present...

  15. Secondary electron emission yield on poled silica based thick films

    DEFF Research Database (Denmark)

    Braga, D.; Poumellec, B.; Cannas, V.;

    2004-01-01

    Studies on the distribution of the electric field produced by a thermal poling process in a layer of Ge-doped silica on silicon substrate, by using secondary electron emission yield (SEEY) measurements () are presented. Comparing 0 between poled and unpoled areas, the SEEY at the origin of electr...

  16. Simulation Tools for Power Electronics Courses Based on Java Technologies

    Science.gov (United States)

    Canesin, Carlos A.; Goncalves, Flavio A. S.; Sampaio, Leonardo P.

    2010-01-01

    This paper presents interactive power electronics educational tools. These interactive tools make use of the benefits of Java language to provide a dynamic and interactive approach to simulating steady-state ideal rectifiers (uncontrolled and controlled; single-phase and three-phase). Additionally, this paper discusses the development and use of…

  17. The Challenge of Producing Fiber-Based Organic Electronic Devices

    Directory of Open Access Journals (Sweden)

    Tobias Könyves-Toth

    2014-07-01

    Full Text Available The implementation of organic electronic devices on fibers is a challenging task, not yet investigated in detail. As was shown earlier, a direct transition from a flat device structure to a fiber substrate is in principle possible. However, a more detailed investigation of the process reveals additional complexities than just the transition in geometry. It will be shown, that the layer formation of evaporated materials behaves differently due to the multi-angled incidence on the fibers surface. In order to achieve homogenous layers the evaporation process has to be adapted. Additionally, the fiber geometry itself facilitates damaging of its surface due to mechanical impact and leads to a high surface roughness, thereby often hindering commercial fibers to be used as substrates. In this article, a treatment of commercial polymer-coated glass fibers will be demonstrated that allows for the fabrication of rather flexible organic light-emitting diodes (OLEDs with cylindrical emission characteristics. Since OLEDs rely the most on a smooth substrate, fibers undergoing the proposed treatment are applicable for other organic electronic devices such as transistors and solar cells. Finally, the technique also supports the future fabrication of organic electronics not only in smart textiles and woven electronics but also in bent surfaces, which opens a wide range of applications.

  18. Electron Charged Graphite-based Hydrogen Storage Material

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Chinbay Q. Fan; D Manager

    2012-03-14

    The electron-charge effects have been demonstrated to enhance hydrogen storage capacity using materials which have inherent hydrogen storage capacities. A charge control agent (CCA) or a charge transfer agent (CTA) was applied to the hydrogen storage material to reduce internal discharge between particles in a Sievert volumetric test device. GTI has tested the device under (1) electrostatic charge mode; (2) ultra-capacitor mode; and (3) metal-hydride mode. GTI has also analyzed the charge distribution on storage materials. The charge control agent and charge transfer agent are needed to prevent internal charge leaks so that the hydrogen atoms can stay on the storage material. GTI has analyzed the hydrogen fueling tank structure, which contains an air or liquid heat exchange framework. The cooling structure is needed for hydrogen fueling/releasing. We found that the cooling structure could be used as electron-charged electrodes, which will exhibit a very uniform charge distribution (because the cooling system needs to remove heat uniformly). Therefore, the electron-charge concept does not have any burden of cost and weight for the hydrogen storage tank system. The energy consumption for the electron-charge enhancement method is quite low or omitted for electrostatic mode and ultra-capacitor mode in comparison of other hydrogen storage methods; however, it could be high for the battery mode.

  19. Ion Beam Induced Charge Collection (IBICC) from Integrated Circuit Test Structures Using a 10 MeV Carbon Microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Aton, T.J.; Doyle, B.L.; Duggan, J.L.; El Bouanani, M.; Guo, B.N.; McDaniel, F.D.; Renfrow, S.N.; Walsh, D.S.

    1998-11-18

    As future sizes of Integrated Circuits (ICs) continue to shrink the sensitivity of these devices, particularly SRAMs and DRAMs, to natural radiation is increasing. In this paper, the Ion Beam Induced Charge Collection (IBICC) technique is utilized to simulate neutron-induced Si recoil effects in ICS. The IBICC measurements, conducted at the Sandia National Laboratories employed a 10 MeV carbon microbeam with 1pm diameter spot to scan test structures on specifically designed ICS. With the aid of layout information, an analysis of the charge collection efficiency from different test areas is presented. In the present work a 10 MeV Carbon high-resolution microbeam was used to demonstrate the differential charge collection efficiency in ICS with the aid of the IC design Information. When ions strike outside the FET, the charge was only measured on the outer ring, and decreased with strike distance from this diode. When ions directly strike the inner and ring diodes, the collected charge was localized to these diodes. The charge for ions striking the gate region was shared between the inner and ring diodes. I The IBICC measurements directly confirmed the interpretations made in the earlier work.

  20. XUV free-electron laser-based projection lithography systems

    International Nuclear Information System (INIS)

    Free-electron laser sources, driven by rf-linear accelerators, have the potential to operate in the extreme ultraviolet (XUV) spectral range with more than sufficient average power for high-volume projection lithography. For XUV wavelengths from 100 nm to 4 nm, such sources will enable the resolution limit of optical projection lithography to be extended from 0.25 μm to 0.05μm and with an adequate total depth of focus (1 to 2 μm). Recent developments of a photoinjector of very bright electron beams, high-precision magnetic undulators, and ring-resonator cavities raise our confidence that FEL operation below 100 nm is ready for prototype demonstration. We address the motivation for an XUV FEL source for commercial microcircuit production and its integration into a lithographic system, include reflecting reduction masks, reflecting XUV projection optics and alignment systems, and surface-imaging photoresists. 52 refs., 7 figs

  1. XUV free-electron laser-based projection lithography systems

    Energy Technology Data Exchange (ETDEWEB)

    Newnam, B.E.

    1990-01-01

    Free-electron laser sources, driven by rf-linear accelerators, have the potential to operate in the extreme ultraviolet (XUV) spectral range with more than sufficient average power for high-volume projection lithography. For XUV wavelengths from 100 nm to 4 nm, such sources will enable the resolution limit of optical projection lithography to be extended from 0.25 {mu}m to 0.05{mu}m and with an adequate total depth of focus (1 to 2 {mu}m). Recent developments of a photoinjector of very bright electron beams, high-precision magnetic undulators, and ring-resonator cavities raise our confidence that FEL operation below 100 nm is ready for prototype demonstration. We address the motivation for an XUV FEL source for commercial microcircuit production and its integration into a lithographic system, include reflecting reduction masks, reflecting XUV projection optics and alignment systems, and surface-imaging photoresists. 52 refs., 7 figs.

  2. Stretchable electronics based on Ag-PDMS composites

    Science.gov (United States)

    Larmagnac, Alexandre; Eggenberger, Samuel; Janossy, Hanna; Vörös, Janos

    2014-12-01

    Patterned structures of flexible, stretchable, electrically conductive materials on soft substrates could lead to novel electronic devices with unique mechanical properties allowing them to bend, fold, stretch or conform to their environment. For the last decade, research on improving the stretchability of circuits on elastomeric substrates has made significant progresses but designing printed circuit assemblies on elastomers remains challenging. Here we present a simple, cost-effective, cleanroom-free process to produce large scale soft electronic hardware where standard surface-mounted electrical components were directly bonded onto all-elastomeric printed circuit boards, or soft PCBs. Ag-PDMS tracks were stencil printed onto a PDMS substrate and soft PCBs were made by bonding the top and bottom layers together and filling punched holes with Ag-PDMS to create vias. Silver epoxy was used to bond commercial electrical components and no mechanical failure was observed after hundreds of stretching cycles. We also demonstrate the fabrication of a stretchable clock generator.

  3. Materials Meets Concepts in Molecule-Based Electronics

    KAUST Repository

    Ortmann, Frank

    2014-10-14

    In this contribution, molecular materials are highlighted as an important topic in the diverse field of condensed matter physics, with focus on their particular electronic and transport properties. A better understanding of their performance in various applications and devices demands for an extension of basic theoretical approaches to describe charge transport in molecular materials, including the accurate description of electron-phonon coupling. Starting with the simplest case of a molecular junction and moving on to larger aggregates of bulk organic semiconductors, charge-transport regimes from ballistic motion to incoherent hopping, which are frequently encountered in molecular systems under respective conditions, are discussed. Transport features of specific materials are described through ab initio material parameters whose determination is addressed. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA.

  4. Electronically Reconfigurable Liquid Crystal Based Mm-Wave Polarization Converter

    OpenAIRE

    Doumanis, E.; Goussetis, G.; Dickie, R.; CAHILL, R; Baine, P; Bain, M; V. Fusco; Encinar, J. A.; Toso, G

    2014-01-01

    An electronically tunable reflection polarizer which exploits the dielectric anisotropy of nematic liquid crystals (LC) has been designed, fabricated and measured in a frequency band centered at 130 GHz. The phase agile polarizing mirror converts an incident slant 45° signal upon reflection to right hand circular (RHCP), orthogonal linear (-45 °) or left hand circular (LHCP) polarization depending on the value of the voltage biasing the LC mixture. In the experimental set-up this is achieved ...

  5. Kinase detection with gallium nitride based high electron mobility transistors.

    Science.gov (United States)

    Makowski, Matthew S; Bryan, Isaac; Sitar, Zlatko; Arellano, Consuelo; Xie, Jinqiao; Collazo, Ramon; Ivanisevic, Albena

    2013-07-01

    A label-free kinase detection system was fabricated by the adsorption of gold nanoparticles functionalized with kinase inhibitor onto AlGaN/GaN high electron mobility transistors (HEMTs). The HEMTs were operated near threshold voltage due to the greatest sensitivity in this operational region. The Au NP/HEMT biosensor system electrically detected 1 pM SRC kinase in ionic solutions. These results are pertinent to drug development applications associated with kinase sensing.

  6. Biomedical stretchable sytems using MID based stretchable electronics technology.

    Science.gov (United States)

    Axisa, F; Brosteaux, D; De Leersnyder, E; Bossuyt, F; Vanfleteren, J; Hermans, B; Puers, R

    2007-01-01

    In order to fit human body, flexibility, or even better stretchability is requested for biomedical systems like implants or smart clothes. A stretchable electronic technology has been developed. This can provide highly stretchable interconnections fully compatible with PCB technologies. In order to prove the feasibility of complex biomedical systems like inner body implants or wearable systems, a variety of stretchable systems has been designed from sensor to power source systems.

  7. Micrometer-resolved film dosimetry using a microscope in microbeam radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bartzsch, Stefan, E-mail: stefan.bartzsch@icr.ac.uk; Oelfke, Uwe [The Institute of Cancer Research, 15 Cotswold Road, Sutton SM2 5NG (United Kingdom); Lott, Johanna; Welsch, Katrin [Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, D-69120 Heidelberg (Germany); Bräuer-Krisch, Elke [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, Grenoble Cedex 9 38043 (France)

    2015-07-15

    Purpose: Microbeam radiation therapy (MRT) is a still preclinical tumor therapy approach that uses arrays of a few tens of micrometer wide parallel beams separated by a few 100 μm. The production, measurement, and planning of such radiation fields are a challenge up to now. Here, the authors investigate the feasibility of radiochromic film dosimetry in combination with a microscopic readout as a tool to validate peak and valley doses in MRT, which is an important requirement for a future clinical application of the therapy. Methods: Gafchromic{sup ®} HD-810 and HD-V2 films are exposed to MRT fields at the biomedical beamline ID17 of the European Synchrotron Radiation Facility (ESRF) and are afterward scanned with a microscope. The measured dose is compared with Monte Carlo calculations. Image analysis tools and film handling protocols are developed that allow accurate and reproducible dosimetry. The performance of HD-810 and HD-V2 films is compared and a detailed analysis of the resolution, noise, and energy dependence is carried out. Measurement uncertainties are identified and analyzed. Results: The dose was measured with a resolution of 5 × 1000 μm{sup 2} and an accuracy of 5% in the peak and between 10% and 15% in the valley region. As main causes for dosimetry uncertainties, statistical noise, film inhomogeneities, and calibration errors were identified. Calibration errors strongly increase at low doses and exceeded 3% for doses below 50 and 70 Gy for HD-V2 and HD-810 films, respectively. While the grain size of both film types is approximately 2 μm, the statistical noise in HD-V2 is much higher than in HD-810 films. However, HD-810 films show a higher energy dependence at low photon energies. Conclusions: Both film types are appropriate for dosimetry in MRT and the microscope is superior to the microdensitometer used before at the ESRF with respect to resolution and reproducibility. However, a very careful analysis of the image data is required

  8. Electron spin relaxation in cryptochrome-based magnetoreception

    DEFF Research Database (Denmark)

    Kattnig, Daniel R; Solov'yov, Ilia A; Hore, P J

    2016-01-01

    The magnetic compass sense of migratory birds is thought to rely on magnetically sensitive radical pairs formed photochemically in cryptochrome proteins in the retina. An important requirement of this hypothesis is that electron spin relaxation is slow enough for the Earth's magnetic field to have...... this question for a structurally characterized model cryptochrome expected to share many properties with the putative avian receptor protein. To this end we combine all-atom molecular dynamics simulations, Bloch-Redfield relaxation theory and spin dynamics calculations to assess the effects of spin relaxation...

  9. Characterisation of a Sr-90 based electron monochromator

    CERN Document Server

    Arfaoui, S; CERN; Casella, C; ETH Zurich

    2015-01-01

    This note describes the characterisation of an energy filtered Sr-90 source to be used in laboratory studies that require Minimum Ionising Particles (MIP) with a kinetic energy of up to approx. 2 MeV. The energy calibration was performed with a LYSO scintillation crystal read out by a digital Silicon Photomultiplier (dSiPM). The LYSO/dSiPM set-up was pre-calibrated using a Na-22 source. After introducing the motivation behind the usage of such a device, this note presents the principle and design of the electron monochromator as well as its energy and momentum characterisation.

  10. Inter-base Electronic Coupling for transport through DNA

    OpenAIRE

    Anantram, H. Mehrez M. P.

    2005-01-01

    We develop a new approach to derive single state tight binding (SSTB) model for electron transport in the vicinity of valence-conduction bands of poly(G)-poly(C) and poly(A)-poly(T) DNA. The SSTB parameters are derived from {\\it first principles} and are used to model charge transport through finite length DNA. We investigate the rigor of reducing the full DNA Hamiltonian to SSTB model to represent charge transport in the vicinity of valence-conduction band. While the transmission coefficient...

  11. Design and implementation of a fs-resolved transmission electron microscope based on thermionic gun technology

    Science.gov (United States)

    Piazza, L.; Masiel, D. J.; LaGrange, T.; Reed, B. W.; Barwick, B.; Carbone, Fabrizio

    2013-09-01

    In this paper, the design and implementation of a femtosecond-resolved ultrafast transmission electron microscope is presented, based on a thermionic gun geometry. Utilizing an additional magnetic lens between the electron acceleration and the nominal condenser lens system, a larger percentage of the electrons created at the cathode are delivered to the specimen without degrading temporal, spatial and energy resolution significantly, while at the same time maintaining the femtosecond temporal resolution. Using the photon-induced near field electron microscopy effect (PINEM) on silver nanowires the cross-correlation between the light and electron pulses was measured, showing the impact of the gun settings and initiating laser pulse duration on the electron bunch properties. Tuneable electron pulses between 300 fs and several ps can be obtained, and an overall energy resolution around 1 eV was achieved.

  12. Final Technical Report- Back-gate Field Emission-based Cathode RF Electron Gun

    Energy Technology Data Exchange (ETDEWEB)

    McGuire, Gary; Martin, Allen; Noonan, John

    2010-10-30

    The objective was to complete the design of an electron gun which utilizes a radio frequency (RF) power source to apply a voltage to a field emission (FE) cathode, a so called cold cathode, in order to produce an electron beam. The concept of the RF electron gun was originally conceived at Argonne National Laboratory but never reduced to practice. The research allowed the completion of the design based upon the integration of the FE electron source. Compared to other electron guns, the RF gun is very compact, less than one third the size of other comparable guns, and produces a high energy (to several MeV), high quality, high power electron beam with a long focal length with high repetition rates. The resultant electron gun may be used in welding, materials processing, analytical equipment and waste treatment.

  13. An active damper for stabilizing power-electronics-based AC systems

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Liserre, Marco;

    2014-01-01

    The interactions among the parallel grid-connected converters coupled through the grid impedance tend to result in stability and power quality problems. To address them, this paper proposes an active damper based on a high bandwidth power electronics converter. The general idea behind this propos...... tests on a three-converter-based setup are carried out. The results show that the active damper can become a promising way to stabilize the power-electronics-based ac power systems....

  14. Production of excited electrons at TESLA and CLIC based egamma colliders

    CERN Document Server

    Kirca, Z; Cakir, O

    2003-01-01

    We analyze the potential of TESLA and CLIC based electron-photon colliders to search for excited spin-1/2 electrons. The production of excited electrons in the resonance channel through the electron- photon collision and their subsequent decays to leptons and electroweak gauge bosons are investigated. We study in detail the three signal channels of excited electrons and the corresponding backgrounds through the reactions egamma yields egamma, egamma yields eZ and egamma yields vW. Excited electrons with masses up to about 90% of the available collider energy can be probed down to the coupling f = f prime = 0.05(0.1) at TESLA(CLIC) based egamma colliders. 22 Refs.

  15. Electronic Transport in Molecular Junction Based on C20 Cages

    Institute of Scientific and Technical Information of China (English)

    OUYANG Fang-Ping; XU Hui

    2007-01-01

    Choosing closed-ended armchair(5,5)single-wall carbon nanotubes(CCNTs)as electrodes,we investigate the electron transport properties across an all-carbon molecular junction consisting of C20 molecules suspended between two semi-infinite carbon nanotubes.It is shown that the conductances are quite sensitive to the number of C20 molecules between electrodes for both configuration CFl and double-bonded models:the conductances of C20 dimers are markedly smaller than those of monomers.The physics is that incident electrons easily pass the C20 molecules and are predominantly scattered at the C20-C20 junctions.Moreover,we study the doping effect of such molecular junction by doping nitrogen atoms substitutionally.The bonding property of the molecular junction with configuration CFl has been analysed by calculating the Mulliken atomic charges.Our results have revealed that the C atoms in N-doped junctions are more ionic than those in pure-carbon ones,leading to the fact that N-doped junctions have relatively large conductance.

  16. Maximum likelihood based classification of electron tomographic data.

    Science.gov (United States)

    Stölken, Michael; Beck, Florian; Haller, Thomas; Hegerl, Reiner; Gutsche, Irina; Carazo, Jose-Maria; Baumeister, Wolfgang; Scheres, Sjors H W; Nickell, Stephan

    2011-01-01

    Classification and averaging of sub-tomograms can improve the fidelity and resolution of structures obtained by electron tomography. Here we present a three-dimensional (3D) maximum likelihood algorithm--MLTOMO--which is characterized by integrating 3D alignment and classification into a single, unified processing step. The novelty of our approach lies in the way we calculate the probability of observing an individual sub-tomogram for a given reference structure. We assume that the reference structure is affected by a 'compound wedge', resulting from the summation of many individual missing wedges in distinct orientations. The distance metric underlying our probability calculations effectively down-weights Fourier components that are observed less frequently. Simulations demonstrate that MLTOMO clearly outperforms the 'constrained correlation' approach and has advantages over existing approaches in cases where the sub-tomograms adopt preferred orientations. Application of our approach to cryo-electron tomographic data of ice-embedded thermosomes revealed distinct conformations that are in good agreement with results obtained by previous single particle studies.

  17. Ballistic Hot Electron Transport in Heteroepitaxial SrRuO3 Metal-Base Transistors

    Science.gov (United States)

    Kim, Brian; Hikita, Yasuyuki; Yajima, Takeaki; Bell, Christopher; Hwang, Harold

    Perovskite oxide heterostructures is a rapidly emerging field significant for interface-induced electronic and magnetic reconstructions, resulting in novel phases distinct from those found in the bulk counterparts. Notably, utilizing device structures is an effective way to probe these interface-induced phases. One of the most prevalent device structures that has been adopted so far is a three-terminal field-effect geometry, used to probe in-plane electronic transport properties. However, the out-of-plane three-terminal device geometry, though less studied due to its complexity, is also useful in many aspects. In the metal-base transistor (MBT), for instance, ballistic transport of hot electrons injected across a Schottky diode emitter can be used to probe hot electron properties of the metal-base, providing information on inelastic scattering mechanisms, electron confinement effects, and intervalley transfer. One promising model system for the metal-base is SrRuO3 (SRO), characterized by intermediate electron correlations with unusual transport properties. Here we present an all-perovskite oxide heteroepitaxial MBT using SRO as a metal-base layer. Successful MBT operation for various metal-base layer thicknesses was achieved, from which the hot electron attenuation length of SRO was deduced. These results form a foundation on which to examine the properties of hot electrons in strongly correlated systems using the out-of-plane three-terminal device geometry.

  18. Bridge- and Solvent-Mediated Intramolecular Electronic Communications in Ubiquinone-Based Biomolecular Wires

    OpenAIRE

    Liu, Xiao-Yuan; Ma, Wei; Zhou, Hao; Cao, Xiao-Ming; Long, Yi-Tao

    2015-01-01

    Intramolecular electronic communications of molecular wires play a crucial role for developing molecular devices. In the present work, we describe different degrees of intramolecular electronic communications in the redox processes of three ubiquinone-based biomolecular wires (Bis-CoQ0s) evaluated by electrochemistry and Density Functional Theory (DFT) methods in different solvents. We found that the bridges linkers have a significant effect on the electronic communications between the two pe...

  19. Behavioral modelling and identification of power electronics converters and subsystems based on transient response

    OpenAIRE

    Valdivia Guerrero, Virgilio

    2013-01-01

    Nowadays, electrical engineers face significant changes in the way the electrical energy is generated and distributed to the consumers. On the one hand, the number of electronic and electrical loads in power distribution systems is continuously growing. Developments in power electronics technology during last decades have enabled the use of power-electronics-based subsystems as an alternative to mechanical, hydraulic and pneumatic subsystems, looking for more reliable and light systems, and a...

  20. The Reflective Type of Electronic Whiteboard Based on Cholesteric Liquid Crystal Display Technology

    OpenAIRE

    TianHua Li

    2013-01-01

    The study analyzes the basic principle and structure of cholesteric liquid crystal display technology and concludes features and requirements of reflective type of electronic whiteboard based on cholesteric liquid crystal display technology. The design of drive circuit of reflective type of electronic whiteboard; the make-up of large reflective type of cholesteric liquid crystal homogeneous display screen as the display equipment of electronic whiteboard; and the adoption of C language to edi...

  1. Concept of a multichannel spin-resolving electron analyzer based on Mott scattering

    Energy Technology Data Exchange (ETDEWEB)

    Strocov, Vladimir N., E-mail: vladimir.strocov@psi.ch [Paul Scherrer Institute, CH-5232 Villigen-PSI (Switzerland); Petrov, Vladimir N. [St Petersburg Polytechnical University, Polytechnicheskaya Str. 29, St Petersburg RU-195251 (Russian Federation); Dil, J. Hugo [Paul Scherrer Institute, CH-5232 Villigen-PSI (Switzerland); École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland)

    2015-04-10

    The concept of a two-dimensional multichannel electron spin detector based on Mott scattering and imaging-type electron optics is presented. The efficiency increase of about four orders of magnitude opens new scientific fields including buried magnetic interfaces. The concept of a multichannel electron spin detector based on optical imaging principles and Mott scattering (iMott) is presented. A multichannel electron image produced by a standard angle-resolving (photo) electron analyzer or microscope is re-imaged by an electrostatic lens at an accelerating voltage of 40 kV onto the Au target. Quasi-elastic electrons bearing spin asymmetry of the Mott scattering are imaged by magnetic lenses onto position-sensitive electron CCDs whose differential signals yield the multichannel spin asymmetry image. Fundamental advantages of this concept include acceptance of inherently divergent electron sources from the electron analyzer or microscope focal plane as well as small aberrations achieved by virtue of high accelerating voltages, as demonstrated by extensive ray-tracing analysis. The efficiency gain compared with the single-channel Mott detector can be a factor of more than 10{sup 4} which opens new prospects of spin-resolved spectroscopies in application not only to standard bulk and surface systems (Rashba effect, topological insulators, etc.) but also to buried heterostructures. The simultaneous spin detection combined with fast CCD readout enables efficient use of the iMott detectors at X-ray free-electron laser facilities.

  2. Multi-Information Model for PCB-Based ElectronicsProduct Manufacturing

    Institute of Scientific and Technical Information of China (English)

    李春泉; 周德俭; 余涛

    2004-01-01

    Most electronics products use PCB to carry electronic circuits. This paper classifies information contained in PCB-based electronic circuits into several models: geometry model, physics model, performance model and function model. Based on this classification, a multi-information model of product is established. A composite model of product is also created based on object-orientation and characteristics of the product. The model includes a 3D geometry model, a physics model with integrated information that can be divided into microscopic and macroscopic information, a generalized performance model and a function model that are from top to bottom. Finally, a multi-unit analysis is briefly discussed.

  3. Note: Design and development of improved indirectly heated cathode based strip electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Namita; Patil, D. S.; Dasgupta, K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Bade, Abhijeet; Tembhare, G. U. [Department of Mechanical Engineering, Veermata Jijabai Technological Institute, Matunga, Mumbai 400 019 (India)

    2015-02-15

    An improved design of indirectly heated solid cathode based electron gun (200 kW, 45 kV, 270° bent strip type electron gun) has been presented. The solid cathode is made of thoriated tungsten, which acts as an improved source of electron at lower temperature. So, high power operation is possible without affecting structural integrity of the electron gun. The design issues are addressed based on the uniformity of temperature on the solid cathode and the single long filament based design. The design approach consists of simulation followed by extensive experimentation. In the design, the effort has been put to tailor the non-uniformity of the heat flux from the filament to the solid cathode to obtain better uniformity of temperature on the solid cathode. Trial beam experiments have been carried out and it is seen that the modified design achieves one to one correspondence of the solid cathode length and the electron beam length.

  4. Note: Design and development of improved indirectly heated cathode based strip electron gun

    International Nuclear Information System (INIS)

    An improved design of indirectly heated solid cathode based electron gun (200 kW, 45 kV, 270° bent strip type electron gun) has been presented. The solid cathode is made of thoriated tungsten, which acts as an improved source of electron at lower temperature. So, high power operation is possible without affecting structural integrity of the electron gun. The design issues are addressed based on the uniformity of temperature on the solid cathode and the single long filament based design. The design approach consists of simulation followed by extensive experimentation. In the design, the effort has been put to tailor the non-uniformity of the heat flux from the filament to the solid cathode to obtain better uniformity of temperature on the solid cathode. Trial beam experiments have been carried out and it is seen that the modified design achieves one to one correspondence of the solid cathode length and the electron beam length

  5. Textile-Based Electronic Components for Energy Applications: Principles, Problems, and Perspective

    Directory of Open Access Journals (Sweden)

    Vishakha Kaushik

    2015-09-01

    Full Text Available Textile-based electronic components have gained interest in the fields of science and technology. Recent developments in nanotechnology have enabled the integration of electronic components into textiles while retaining desirable characteristics such as flexibility, strength, and conductivity. Various materials were investigated in detail to obtain current conductive textile technology, and the integration of electronic components into these textiles shows great promise for common everyday applications. The harvest and storage of energy in textile electronics is a challenge that requires further attention in order to enable complete adoption of this technology in practical implementations. This review focuses on the various conductive textiles, their methods of preparation, and textile-based electronic components. We also focus on fabrication and the function of textile-based energy harvesting and storage devices, discuss their fundamental limitations, and suggest new areas of study.

  6. The ERL-based Design of Electron-Hadron Collider eRHIC

    Energy Technology Data Exchange (ETDEWEB)

    Ptitsyn, Vadim; et al.

    2016-06-01

    Recent developments of the ERL-based design of future high luminosity electron-hadron collider eRHIC focused on balancing technological risks present in the design versus the design cost. As a result a lower risk design has been adopted at moderate cost increase. The modifications include a change of the main linac RF frequency, reduced number of SRF cavity types and modified electron spin transport using a spin rotator. A luminosity-staged approach is being explored with a Nominal design ($L \\sim 10^{33} {\\rm cm}^2 {\\rm s}^{-1}$) that employs reduced electron current and could possibly be based on classical electron cooling, and then with the Ultimate design ($L \\gt 10^{34} {\\rm cm}^{-2} {\\rm s}^{-1}$) that uses higher electron current and an innovative cooling technique (CeC). The paper describes the recent design modifications, and presents the full status of the eRHIC ERL-based design.

  7. Compact, high power electron beam based terahertz sources.

    Energy Technology Data Exchange (ETDEWEB)

    Biedron, S. G.; Lewellen, J. W.; Milton, S. V.; Gopalsami, N.; Schneider, J. F.; Skubal, L.; Li, Y. L.; Virgo, M.; Gallerano, G. P.; Doria, A.; Giovenale, E.; Messina, G.; Spasovsky, I. P.; Office of The Director-Applied Science and Technology; Univ. of Maryland; ENEA

    2007-08-01

    Although terahertz (THz) radiation was first observed about 100 years ago, this portion of the electromagnetic spectrum at the boundary between the microwaves and the infrared has been, for a long time, rather poorly explored. This situation changed with the rapid development of coherent THz sources such as solid-state oscillators, quantum cascade lasers, optically pumped solid-state devices, and novel coherent radiator devices. These in turn have stimulated a wide variety of applications from material science to telecommunications, from biology to biomedicine. Recently, there have been two related compact coherent radiation devices invented able to produce up to megawatts of peak THz power by inducing a ballistic bunching effect on the electron beam, forcing the beam to radiate coherently. An introduction to the two systems and the corresponding output photon beam characteristics will be provided.

  8. Electronic Nose Based on an Optimized Competition Neural Network

    Directory of Open Access Journals (Sweden)

    Haiping Zhang

    2011-05-01

    Full Text Available In view of the fact that there are disadvantages in that the class number must be determined in advance, the value of learning rates are hard to fix, etc., when using traditional competitive neural networks (CNNs in electronic noses (E-noses, an optimized CNN method was presented. The optimized CNN was established on the basis of the optimum class number of samples according to the changes of the Davies and Bouldin (DB value and it could increase, divide, or delete neurons in order to adjust the number of neurons automatically. Moreover, the learning rate changes according to the variety of training times of each sample. The traditional CNN and the optimized CNN were applied to five kinds of sorted vinegars with an E-nose. The results showed that optimized network structures could adjust the number of clusters dynamically and resulted in good classifications.

  9. Chemical bonding and electronic structure of fullerene-based compounds

    International Nuclear Information System (INIS)

    This talk will focus on the nature of bonding of fullerenes with other materials as demonstrated by synchrotron radiation and x-ray photoemission. Adsorption of C60 on metallic and semiconducting substrates occurs via charge transfer from the substrate to a LUMO-derived resonance, resulting in Fermi level alignment and dipole formation. Bonding of metal atoms to C60 depends on the metal work function and bulk cohesive energy. Evaporation of high cohesive energy materials onto a fullerene substrate results in metal cluster nucleation and limited C60 disruption for transition metals. Low cohesive energy metals form compounds with a degree of ionic character related to the metal work function. Photoemission results show the formation of ionic K-fulleride compounds while greater hybridization is observed for Ca-rich fullerides. Finally the electronic structure of fluorinated and hydrogenated fullerenes demonstrate changes in states derived from C60 π bonds due to reaction of dangling bonds

  10. ELECTRONIC BANKING SERVICES IN ECONOMY BASED ON KNOWLEDGE

    Directory of Open Access Journals (Sweden)

    Răbonţu Cecilia Irina

    2009-05-01

    Full Text Available The term "electronic banking" or "ebanking" covers both computer and telephone banking. Using computer banking, a charity’s computer either dials directly into its bank's computer or gains access to the bank’s computer over the internet. Using telephone banking, the charity controls its bank accounts by giving the bank instructions over the telephone. Both computer and telephone banking involve the use of passwords which give access to the charity’s accounts. Technological innovation and competition among existing banking organizations have allowed a wider array of banking products and services to become accessible and delivered through the Internet. The rapid development of e-banking capabilities carries risks as well as benefits. The bankers are to recognize, address and manage banking institutions in a prudent manner according to the fundamental characteristics and challenges of e-banking services

  11. Electron scattering times in ZnO based polar heterostructures

    International Nuclear Information System (INIS)

    The remarkable historic advances experienced in condensed matter physics have been enabled through the continued exploration and proliferation of increasingly richer and cleaner material systems. In this work, we report on the scattering times of charge carriers confined in state-of-the-art MgZnO/ZnO heterostructures displaying electron mobilities in excess of 106 cm2/V s. Through an examination of low field quantum oscillations, we obtain the effective mass of charge carriers, along with the transport and quantum scattering times. These times compare favorably with high mobility AlGaAs/GaAs heterostructures, suggesting the quality of MgZnO/ZnO heterostructures now rivals that of traditional semiconductors

  12. Electron scattering times in ZnO based polar heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Falson, J., E-mail: j.falson@fkf.mpg.de [Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656 (Japan); Department of Advanced Materials Science, The University of Tokyo, Kashiwa 277-8561 (Japan); Max Planck Institute for Solid State Research, D-70569 Stuttgart (Germany); Kozuka, Y. [Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656 (Japan); Smet, J. H. [Max Planck Institute for Solid State Research, D-70569 Stuttgart (Germany); Arima, T. [Department of Advanced Materials Science, The University of Tokyo, Kashiwa 277-8561 (Japan); RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); Tsukazaki, A. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); PRESTO, Japan Science and Technology Agency (JST), Tokyo 102-0075 (Japan); Kawasaki, M. [Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656 (Japan); RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan)

    2015-08-24

    The remarkable historic advances experienced in condensed matter physics have been enabled through the continued exploration and proliferation of increasingly richer and cleaner material systems. In this work, we report on the scattering times of charge carriers confined in state-of-the-art MgZnO/ZnO heterostructures displaying electron mobilities in excess of 10{sup 6} cm{sup 2}/V s. Through an examination of low field quantum oscillations, we obtain the effective mass of charge carriers, along with the transport and quantum scattering times. These times compare favorably with high mobility AlGaAs/GaAs heterostructures, suggesting the quality of MgZnO/ZnO heterostructures now rivals that of traditional semiconductors.

  13. Monitoring of MMCA-based Military Electronic Information System

    Institute of Scientific and Technical Information of China (English)

    ZHANG De-yu,; PAN Cheng-sheng; YANG Jing-yu

    2005-01-01

    A multiplex monitoring and control architecture (MMCA) for military supervision based on common information model (CIM) is put forward after analyzing the features of military system. Information format based on CIM can be compatible with other protocols by mapping data type into that of SNMP, DMI and CMIP, etc. And in order to realize transparence and dynamic expansibility of MMCA administrator, CIM object manager and CIM object provider are designed based on monitoring mechanism of agent extensibility--AgentX that MMCA agent uses.

  14. Clear as Glass: A Combined List of Print and Electronic Journals in the Knowledge Base

    Science.gov (United States)

    Lowe, M. Sara

    2008-01-01

    The non-standard practice at Cowles Library at Drake University has been to display electronic journals and some print journals in the Knowledge Base while simultaneously listing print journals and some electronic journals in the online public access catalog (OPAC). The result was a system that made it difficult for patrons to determine our…

  15. A bias-tunable electron-spin filter based on a two-dimensional electron gas modulated by ferromagnetic-Schottky metal stripes

    International Nuclear Information System (INIS)

    We investigate the effect of the bias in an electron-spin filter based on a two-dimensional electron gas modulated by ferromagnetic-Schottky metal stripes. The numerical results show that the electron transmission and the conductance as well as the spin polarization are strongly dependent on the bias applied to the device. - Research highlights: → We propose a bias-tunable electron-spin filter. → The transmission and the conductance depend on the bias and the electron energy. → The spin polarization depends on the bias and the electron energy. → The results are helpful for making new types of bias-tunable spin filters.

  16. Problem-Based and Project-Oriented Learning. An Efficient Way to Implement Research Based Teaching in Power Electronic

    Science.gov (United States)

    Blaabjerg, Frede; Teodorescu, Remus; Chen, Zhe

    Power electronics is an emerging technology. New applications are added every year as well as the power handling capabilities is steadily increasing. One example is renewable energy, which is efficiently enabled by power electronics. The demands to the education of engineers in this field are also increasing. Generally, the content of the curriculum should be more expanded without extra study time. This paper presents a teaching approach, which very fast makes it possible for the students to obtain in-depth skills into new research areas, and this method is the problem-oriented and project-based learning. The necessary skills for power electronic engineers are outlined that is followed up by a description on how the problem-oriented and project-based learning are implemented. A complete curriculum in power electronics and drives at Aalborg University is presented where different power electronics related projects at different study levels are finally presented.

  17. Teaching Electronic Literacy A Concepts-Based Approach for School Library Media Specialists

    CERN Document Server

    Craver, Kathleen W

    1997-01-01

    School library media specialists will find this concepts-based approach to teaching electronic literacy an indispensable basic tool for instructing students and teachers. It provides step-by-step instruction on how to find and evaluate needed information from electronic databases and the Internet, how to formulate successful electronic search strategies and retrieve relevant results, and how to interpret and critically analyze search results. The chapters contain a suggested lesson plan and sample assignments for the school library media specialist to use in teaching electronic literacy skills

  18. On the problem of electron-induced anisotropy effect in As2S3-based glasses

    International Nuclear Information System (INIS)

    Effect of electron-induced anisotropy was observed in glassy As2S3-based samples irradiated by accelerated electrons (E=2.8 MeV) in the perpendicular plane to the probe light. Spectral and compositional dependences of this effect and its time stability at room temperature were discussed. It was supposed that the microstructural mechanism of the anisotropy effect was connected with electron-induced formation of new oriented (relatively to the electron flow) defects in the form of broken chemical bonds

  19. Heavy Ion Injection Into Synchrotrons, Based On Electron String Ion Sources

    CERN Document Server

    Donets, E E; Syresin, E M

    2004-01-01

    A possibility of heavy ions injection into synchrotrons is discussed on the base of two novel ion sources, which are under development JINR during last decade: 1) the electron string ion source (ESIS), which is a modified version of a conventional electron beam ion source (EBIS), working in a reflex mode of operation, and 2) the tubular electron string ion source (TESIS). The Electron String Ion Source "Krion-2" (VBLHE, JINR, Dubna) with an applied confining magnetic field of 3 T was used for injection into the superconducting JINR synchrotron - Nuclotron and during this runs the source provided a high pulse intensity of the highly charged ion beams: Ar16+

  20. The analysis of single-electron orbits in a free electron laser based upon a rectangular hybrid wiggler

    Energy Technology Data Exchange (ETDEWEB)

    Kordbacheh, A.; Ghahremaninezhad, Roghayeh [Department of Physics, Iran University of Science and Technology, 1684613114 Tehran (Iran, Islamic Republic of); Maraghechi, B. [Department of Physics, Amirkabir University of Technology, 159163411 Tehran (Iran, Islamic Republic of)

    2012-09-15

    A three-dimensional analysis of a novel free-electron laser (FEL) based upon a rectangular hybrid wiggler (RHW) is presented. This RHW is designed in a configuration composed of rectangular rings with alternating ferrite and dielectric spacers immersed in a solenoidal magnetic field. An analytic model of RHW is introduced by solution of Laplace's equation for the magnetostatic fields under the appropriate boundary conditions. The single-electron orbits in combined RHW and axial guide magnetic fields are studied when only the first and the third spatial harmonic components of the RHW field are taken into account and the higher order terms are ignored. The results indicate that the third spatial harmonic leads to group III orbits with a strong negative mass regime particularly in large solenoidal magnetic fields. RHW is found to be a promising candidate with favorable characteristics to be used in microwave FEL.

  1. The analysis of single-electron orbits in a free electron laser based upon a rectangular hybrid wiggler

    Science.gov (United States)

    Kordbacheh, A.; Ghahremaninezhad, Roghayeh; Maraghechi, B.

    2012-09-01

    A three-dimensional analysis of a novel free-electron laser (FEL) based upon a rectangular hybrid wiggler (RHW) is presented. This RHW is designed in a configuration composed of rectangular rings with alternating ferrite and dielectric spacers immersed in a solenoidal magnetic field. An analytic model of RHW is introduced by solution of Laplace's equation for the magnetostatic fields under the appropriate boundary conditions. The single-electron orbits in combined RHW and axial guide magnetic fields are studied when only the first and the third spatial harmonic components of the RHW field are taken into account and the higher order terms are ignored. The results indicate that the third spatial harmonic leads to group III orbits with a strong negative mass regime particularly in large solenoidal magnetic fields. RHW is found to be a promising candidate with favorable characteristics to be used in microwave FEL.

  2. First principles based multiparadigm modeling of electronic structures and dynamics

    Science.gov (United States)

    Xiao, Hai

    Electronic structures and dynamics are the key to linking the material composition and structure to functionality and performance. An essential issue in developing semiconductor devices for photovoltaics is to design materials with optimal band gaps and relative positioning of band levels. Approximate DFT methods have been justified to predict band gaps from KS/GKS eigenvalues, but the accuracy is decisively dependent on the choice of XC functionals. We show here for CuInSe2 and CuGaSe2, the parent compounds of the promising CIGS solar cells, conventional LDA and GGA obtain gaps of 0.0-0.01 and 0.02-0.24 eV (versus experimental values of 1.04 and 1.67 eV), while the historically first global hybrid functional, B3PW91, is surprisingly the best, with band gaps of 1.07 and 1.58 eV. Furthermore, we show that for 27 related binary and ternary semiconductors, B3PW91 predicts gaps with a MAD of only 0.09 eV, which is substantially better than all modern hybrid functionals, including B3LYP (MAD of 0.19 eV) and screened hybrid functional HSE06 (MAD of 0.18 eV). The laboratory performance of CIGS solar cells (> 20% efficiency) makes them promising candidate photovoltaic devices. However, there remains little understanding of how defects at the CIGS/CdS interface affect the band offsets and interfacial energies, and hence the performance of manufactured devices. To determine these relationships, we use the B3PW91 hybrid functional of DFT with the AEP method that we validate to provide very accurate descriptions of both band gaps and band offsets. This confirms the weak dependence of band offsets on surface orientation observed experimentally. We predict that the CBO of perfect CuInSe2/CdS interface is large, 0.79 eV, which would dramatically degrade performance. Moreover we show that band gap widening induced by Ga adjusts only the VBO, and we find that Cd impurities do not significantly affect the CBO. Thus we show that Cu vacancies at the interface play the key role in

  3. Cherenkov light-based beam profiling for ultrarelativistic electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Adli, E., E-mail: Erik.Adli@fys.uio.no [Department of Physics, University of Oslo, N-0316 Oslo (Norway); SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Gessner, S.J.; Corde, S.; Hogan, M.J. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Bjerke, H.H. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

    2015-05-21

    We describe a beam profile monitor design based on Cherenkov light emitted from a charged particle beam in an air gap. The main components of the profile monitor are silicon wafers used to reflect Cherenkov light onto a camera lens system. The design allows for measuring large beam sizes, with large photon yield per beam charge and excellent signal linearity with beam charge. The profile monitor signal is independent of the particle energy for ultrarelativistic particles. Different design and parameter considerations are discussed. A Cherenkov light-based profile monitor has been installed at the FACET User Facility at SLAC. We report on the measured performance of this profile monitor.

  4. Use and Characteristics of Electronic Health Record Systems among Office-Based Physician Practices: United States, ...

    Science.gov (United States)

    ... National Ambulatory Medical Care Survey Adoption of basic EHR systems by office-based physicians increased 21% between ... Survey, Electronic Health Records Survey. Adoption of basic EHR systems and any EHR system varied widely across ...

  5. Investigation of the Dynamics of a Clamped-Clamped Microbeam Near the Third Mode Using a Partial Electrode

    KAUST Repository

    Masri, Karim M.

    2014-08-17

    We present an investigation of the dynamics of a clamped-clamped microbeam excited electrostatically near its third mode. To maximize the response at the third mode, a partial electrode configuration is utilized. A multi-mode Galerkin method is used to develop a reduced order model (ROM) of the beam. A shooting method to find the periodic motion is utilized to generate frequency response curves. The curves show hardenining behavior and dynamic pull-in. We show that the dynamic amplitude of the partial configuration is higher than that of a full electrode configuration. These results are promising for the use of higher-order modes for mass detection and for ultra sensitive resonant sensors.

  6. Recent developments of ion beam induced luminescence at the external scanning microbeam facility of the LABEC laboratory in Florence

    Science.gov (United States)

    Colombo, E.; Calusi, S.; Cossio, R.; Giuntini, L.; Giudice, A. Lo; Mandò, P. A.; Manfredotti, C.; Massi, M.; Mirto, F. A.; Vittone, E.

    2008-04-01

    A new ionoluminescence (IL) apparatus has been successfully installed at the external scanning microbeam facility of the 3 MV Tandetron accelerator of the INFN LABEC in Firenze; the apparatus for photon detection has been fully integrated in the existing ion beam analysis (IBA) set-up, for the simultaneous acquisition of IL and PIXE/PIGE/BS spectra and maps. The potential of the new set-up is illustrated in this paper by some results extracted by the analysis of art objects and advanced semiconductor materials. In particular, the adequacy of the new IBA set-up in the field of cultural heritage is pointed out by the coupled PIXE/IL micro-analysis of a lapis lazuli stone; concerning applications in material science, IL spectra from a N doped diamond sample were acquired and compared with CL analyses to evaluate the relevant sensitivities and the effect of ion damage.

  7. Treatment of Electronic Energy Level Transition and Ionization Following the Particle-Based Chemistry Model

    Science.gov (United States)

    Liechty, Derek S.; Lewis, Mark

    2010-01-01

    A new method of treating electronic energy level transitions as well as linking ionization to electronic energy levels is proposed following the particle-based chemistry model of Bird. Although the use of electronic energy levels and ionization reactions in DSMC are not new ideas, the current method of selecting what level to transition to, how to reproduce transition rates, and the linking of the electronic energy levels to ionization are, to the author s knowledge, novel concepts. The resulting equilibrium temperatures are shown to remain constant, and the electronic energy level distributions are shown to reproduce the Boltzmann distribution. The electronic energy level transition rates and ionization rates due to electron impacts are shown to reproduce theoretical and measured rates. The rates due to heavy particle impacts, while not as favorable as the electron impact rates, compare favorably to values from the literature. Thus, these new extensions to the particle-based chemistry model of Bird provide an accurate method for predicting electronic energy level transition and ionization rates in gases.

  8. Project-Based Learning in Electronic Technology: A Case Study

    Science.gov (United States)

    Li, Li

    2015-01-01

    A case study of project-based learning (PBL) implemented in Tianjin University of Technology and Education is presented. This multidiscipline project is innovated to meet the novel requirements of industry while keeping its traditional effectiveness in driving students to apply knowledge to practice and problem-solving. The implementation of PBL…

  9. A Series-LC-Filtered Active Damper for AC Power Electronics Based Power Systems

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang;

    2015-01-01

    This paper proposes an active damper with a series LC-filter for suppressing resonances in an ac power electronics based power system. The added filter capacitor helps to lower the voltage stress of the converter to be used for implementing the damper. Unlike active filters for the compensation...... is built, where the damper is integrated into a grid-connected converter. The results obtained from the experiments demonstrate the stability enhancement of ac power electronics based power systems by the active damper....

  10. An ANFIS-based on B2C electronic commerce transaction

    International Nuclear Information System (INIS)

    The purpose of this study is to use an adaptive-network-based fuzzy inference system to model a fuzzy logic-based system (FIS) for supporting decision-making process in B2C electronic commerce transaction. Firstly we introduce FIS in B2C electronic commerce transaction and ANFIS. Then we use ANFIS to model FIS with different membership functions(MF). Lastly we give a conclusion

  11. Integration of Evidence into a Detailed Clinical Model-based Electronic Nursing Record System

    OpenAIRE

    Park, Hyeoun-Ae; Min, Yul Ha; Jeon, Eunjoo; Chung, Eunja

    2012-01-01

    Objectives The purpose of this study was to test the feasibility of an electronic nursing record system for perinatal care that is based on detailed clinical models and clinical practice guidelines in perinatal care. Methods This study was carried out in five phases: 1) generating nursing statements using detailed clinical models; 2) identifying the relevant evidence; 3) linking nursing statements with the evidence; 4) developing a prototype electronic nursing record system based on detailed ...

  12. An ANFIS-based on B2C electronic commerce transaction

    Science.gov (United States)

    Lin, Juan; Liu, Chenlian; Guo, Yongning

    2014-10-01

    The purpose of this study is to use an adaptive-network-based fuzzy inference system to model a fuzzy logic-based system (FIS) for supporting decision-making process in B2C electronic commerce transaction. Firstly we introduce FIS in B2C electronic commerce transaction and ANFIS. Then we use ANFIS to model FIS with different membership functions(MF). Lastly we give a conclusion.

  13. An ANFIS-based on B2C electronic commerce transaction

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Juan, E-mail: linjuanliucaihong@qq.com [Department of Mathematics and Computer Science, Fuqing Branch of Fujian Normal University, Fuqing 350300 (China); Liu, Chenlian, E-mail: chenglian.liu@gmail.com [School of Mathematics and Computer Science, Long Yan University, Longyan 364012 (China); Guo, Yongning, E-mail: guoyn@163.com [Fuqing Branch of Fujian Normal University, Fuqing 350300 (China)

    2014-10-06

    The purpose of this study is to use an adaptive-network-based fuzzy inference system to model a fuzzy logic-based system (FIS) for supporting decision-making process in B2C electronic commerce transaction. Firstly we introduce FIS in B2C electronic commerce transaction and ANFIS. Then we use ANFIS to model FIS with different membership functions(MF). Lastly we give a conclusion.

  14. Set-Based Concurrent Engineering Model for Automotive Electronic/Software Systems Development

    OpenAIRE

    Al-Ashaab, Ahmed; Howell, S.; Usowicz, K.; Hernando Anta, P.; Gorka, A.

    2009-01-01

    This paper is presenting a proposal of a novel approach to automotive electronic/software systems development. It is based on the combination of Set-Based Concurrent Engineering, a Toyota approach to product development, with the standard V-Model of software development. Automotive industry currently faces the problem of growing complexity of electronic/software systems. This issue is especially visible at the level of integration of these systems which is difficult and error-pron...

  15. A Perylene-Based Microporous Coordination Polymer Interacts Selectively with Electron-Poor Aromatics.

    Science.gov (United States)

    Tran, Ly D; Ma, Jialiu; Wong-Foy, Antek G; Matzger, Adam J

    2016-04-11

    The design, synthesis, and properties of the new microporous coordination polymer UMCM-310 are described. The unique electronic character of the perylene-based linker enables selective interaction with electron-poor aromatics leading to efficient separation of nitroaromatics. UMCM-310 possesses high surface area and large pore size and thus permits the separation of large organic molecules based on adsorption rather than size exclusion.

  16. Damaging and protective bystander cross-talk between human lung cancer and normal cells after proton microbeam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Desai, Sejal [Radiation Signalling and Cancer Biology Section, Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kobayashi, Alisa; Konishi, Teruaki; Oikawa, Masakazu [Radiation System and Engineering Section, Department of Technical Support and Development, Research, Development and Support Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Pandey, Badri N., E-mail: badrinarain@yahoo.co.in [Radiation Signalling and Cancer Biology Section, Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2014-05-15

    Graphical abstract: - Highlights: • Proton-microbeam irradiated A549 cells send damaging signals to bystander A549 cells. • Irradiated A549–A549 bystander response is through gap junctional communication. • Bystander WI38 cells exert protective signalling in irradiated A549 cells. • Rescue of irradiated A549 cells by WI38 cells is independent of gap junctions. - Abstract: Most of the studies of radiation-induced bystander effects (RIBE) have been focused on understanding the radiobiological changes observed in bystander cells in response to the signals from irradiated cells in a normal cell population with implications to radiation risk assessment. However, reports on RIBE with relevance to cancer radiotherapy especially investigating the bidirectional and criss-cross bystander communications between cancer and normal cells are limited. Hence, in present study employing co-culture approach, we have investigated the bystander cross-talk between lung cancer (A549) and normal (WI38) cells after proton-microbeam irradiation using γ-H2AX foci fluorescence as a measure of DNA double-strand breaks (DSBs). We observed that in A549–A549 co-cultures, irradiated A549 cells exert damaging effects in bystander A549 cells, which were found to be mediated through gap junctional intercellular communication (GJIC). However, in A549–WI38 co-cultures, irradiated A549 did not affect bystander WI38 cells. Rather, bystander WI38 cells induced inverse protective signalling (rescue effect) in irradiated A549 cells, which was independent of GJIC. On the other hand, in response to irradiated WI38 cells neither of the bystander cells (A549 or WI38) showed significant increase in γ-H2AX foci. The observed bystander signalling between tumour and normal cells may have potential implications in therapeutic outcome of cancer radiotherapy.

  17. Characterization of front-end electronics for CZT based handheld radioisotope identifier

    Energy Technology Data Exchange (ETDEWEB)

    Lombigit, L., E-mail: lojius@nm.gov.my [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Rahman, Nur Aira Abd; Mohamad, Glam Hadzir Patai; Ibrahim, Maslina Mohd; Yussup, Nolida; Yazid, Khairiah; Jaafar, Zainudin

    2016-01-22

    A radioisotope identifier device based on large volume Co-planar grid CZT detector is current under development at Malaysian Nuclear Agency. This device is planned to be used for in-situ identification of radioisotopes based on their unique energies. This work reports on electronics testing performed on the front-end electronics (FEE) analog section comprising charge sensitive preamplifier-pulse shaping amplifier chain. This test involves measurement of charge sensitivity, pulse parameters and electronics noise. This report also present some preliminary results on the spectral measurement obtained from gamma emitting radioisotopes.

  18. Generation of electron beams from a laser-based advanced accelerator at Shanghai Jiao Tong University

    CERN Document Server

    Elsied, Ahmed M M; Li, Song; Mirzaie, Mohammad; Sokollik, Thomas; Zhang, Jie

    2014-01-01

    At Shanghai Jiao Tong University, we have established a research laboratory for advanced acceleration research based on high-power lasers and plasma technologies. In a primary experiment based on the laser wakefield acceleration (LWFA) scheme, multi-hundred MeV electron beams having a reasonable quality are generated using 20-40 TW, 30 femtosecond laser pulses interacting independently with helium, neon, nitrogen and argon gas jet targets. The laser-plasma interaction conditions are optimized for stabilizing the electron beam generation from each type of gas. The electron beam pointing angle stability and divergence angle as well as the energy spectra from each gas jet are measured and compared.

  19. High Efficiency and Light Mobile Electronic Business System Based on Mobile Agent Middleware

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yunyong; LIU Jinde

    2004-01-01

    Mobile Network technology has been being the research focus during the 1990's.The middleware technology is imported for the sake of running distributed transaction smoothly.In this paper,a mobile agent based middleware high efficiency mobile electronic business oriented middleware (HEMEBOM) is designed and implemented based on the requirement and background of collaborative electronic business.Its architecture,elements and excellent properties are mainly focused.Then high efficiency mobile electronic business systemμMcommerce is built using HEMEBOM.

  20. Extremely Electron-Rich, Boron-Functionalized, Icosahedral Carborane-Based Phosphinoboranes

    Science.gov (United States)

    Spokoyny, Alexander M.; Lewis, Calvin D.; Teverovskiy, Georgiy; Buchwald, Stephen L.

    2012-01-01

    We have prepared the first examples of B9-connected trivalent aryl and alkyl phosphinoborane species via Pd-catalyzed phosphination of 9-iodo-meta-carborane. Our studies highlight the unique electronic features of the B9-connected meta-carboranyl moiety as compared to its C1-based analogue. This work suggests that the B9-functionalized meta-carboranyl substituent in these ligands exhibits more electron-releasing character than any other known carbon-based substituent, ultimately laying the foundation for a new class of phosphine ligands with extremely electron-rich character. PMID:23667288

  1. Enhanced Role Based Access Control Mechanism for Electronic Examination System

    Directory of Open Access Journals (Sweden)

    Adebukola Onashoga

    2014-02-01

    Full Text Available Over the years, e-learning and e-examination has become standard in many institutions of higher learning. It has been observed that examination questions and results can be easily intercepted by invalid users, thus the security of resources shared among valid users is not guaranteed. In order to solve these problems as it relates to access control, a Role based Examination System (RBES was designed, developed and evaluated. RBES attempted to solve the security issue by the combination of two authentication techniques: text-based authentication and graphical password authentication. The Text-based authentication utilizes two text-based parameters namely the username and password. The graphical password authentication makes use of a finite set of controls (RBES chooses radio buttons which are identified by numbers. These numbers constitute the password used for graphical authentication. To improve on resource sharing among users in the examination system, RBES proposes role management (role creation, role update, role removal and user management (user creation, user update and user removal. The developed system made use of asp.net, C#, IIS server, WAMP server, Mysql and other tools for its development. RBES was tested by some legitimate and illegitimate users and the performance of the system was found to be satisfactory, hence RBES shows an efficient and reliable scheme that can be deployed in any examination or e-learning system. Finally the potential threats to the system were modeled and the use of weak passwords was found to be the most likely threat the system could be vulnerable to.

  2. Technology Trust in Internet-Based Interorganizational Electronic Commerce

    OpenAIRE

    Pauline Ratnasingam; Paul A. Pavlou

    2003-01-01

    Trust in Internet-based Business-to-Business (B2B) e-commerce is an important issue for both practicioners and academicians. Whereas the traditional notion of dyadic interfirm trust primarily focuses on trust in a trading partner firm, trust in e-commerce also implicitly incorporates the notion of trust in the transaction infrastructure and underlying control mechanisms (technology trust), which deals with transaction integrity, authentication, confidentliality, non-repudiation, and best busi...

  3. Research on mobile electronic commerce security technology based on WPKI

    Science.gov (United States)

    Zhang, Bo

    2013-07-01

    Through the in-depth study on the existing mobile e-commerce and WAP protocols, this paper presents a security solution of e-commerce system based on WPKI, and describes its implementation process and specific implementation details. This solution uniformly distributes the key used by the various participating entities , to fully ensure the confidentiality, authentication, fairness and integrity of mobile e-commerce payments, therefore has some pract ical value for improving the security of e-commerce system.

  4. Fiber-based wearable electronics: a review of materials, fabrication, devices, and applications.

    Science.gov (United States)

    Zeng, Wei; Shu, Lin; Li, Qiao; Chen, Song; Wang, Fei; Tao, Xiao-Ming

    2014-08-20

    Fiber-based structures are highly desirable for wearable electronics that are expected to be light-weight, long-lasting, flexible, and conformable. Many fibrous structures have been manufactured by well-established lost-effective textile processing technologies, normally at ambient conditions. The advancement of nanotechnology has made it feasible to build electronic devices directly on the surface or inside of single fibers, which have typical thickness of several to tens microns. However, imparting electronic functions to porous, highly deformable and three-dimensional fiber assemblies and maintaining them during wear represent great challenges from both views of fundamental understanding and practical implementation. This article attempts to critically review the current state-of-arts with respect to materials, fabrication techniques, and structural design of devices as well as applications of the fiber-based wearable electronic products. In addition, this review elaborates the performance requirements of the fiber-based wearable electronic products, especially regarding the correlation among materials, fiber/textile structures and electronic as well as mechanical functionalities of fiber-based electronic devices. Finally, discussions will be presented regarding to limitations of current materials, fabrication techniques, devices concerning manufacturability and performance as well as scientific understanding that must be improved prior to their wide adoption.

  5. Study of electron focusing in thick GEM based photon detectors using semitransparent photocathodes

    Energy Technology Data Exchange (ETDEWEB)

    Baishali, G., E-mail: baishali@isu.iisc.ernet.in [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Radhakrishna, V.; Koushal, V.; Rakhee, K. [Space Astronomy Group, ISRO Satellite Centre, Bangalore 560017 (India); Rajanna, K. [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 (India)

    2013-11-21

    The detection efficiency of a GEM based UV sensitive gaseous photomultiplier (GPM) depends on the focusing of electrons from the drift gap to the GEM aperture. We have studied the effect of drift parameters on the efficiency of electron focusing into Thick GEM (THGEM) holes in a GPM with semitransparent UV photoconverter. This study comprises simulation of electron focusing into THGEM holes using GARFIELD for different Ar and Ne based gas mixtures and experimental investigations of the same with P10 gas mixture. -- Highlights: •Effect of drift parameters on detection efficiency of a THGEM based GPM is studied. •Drift parameters studied are drift field, drift gap, gas composition and pressure. •GARFIELD simulation on Electron Transfer Efficiency for various drift parameters. •Experimental studies were carried out for P10 gas at lower multiplication voltage. •Optimization of drift parameters for maximizing the detection efficiency.

  6. Coherent photon beam based diagnostics for a seeded extreme ultraviolet free electron laser

    CERN Document Server

    Deng, Haixiao; Liu, Bo; Tian, Shunqiang; Zhang, Manzhou; Zhang, Meng

    2012-01-01

    Independently from electron beam based procedures, photon beam based diagnostics is an alternative way for alignment and commissioning of the numerous undulator cells in high-gain short-wavelength free electron laser (FEL). In this paper, using the seed laser modulated electron beam and the undulator fine tuning technique, a coherent photon beam based diagnostic was proposed for seeded FEL, and some preliminary experimental results at Shanghai deep ultraviolet FEL test facility was presented. It shows that spatial distribution analysis of the coherent harmonic radiation of individual or two consecutive undulator segments can be used to optimize the electron beam trajectory, to verify the magnetic gap, and to adjust the phase match between two undulator segments.

  7. Design and implementation of a fs-resolved transmission electron microscope based on thermionic gun technology

    International Nuclear Information System (INIS)

    Highlights: • We present the implementation of a femtosecond-resolved ultrafast TEM. • This is the first ultrafast TEM based on a thermionic gun geometry. • An additional condenser lens has been used to maximize the electron count. • We achieved a time resolution of about 300 fs and an energy resolution of 1 eV. - Abstract: In this paper, the design and implementation of a femtosecond-resolved ultrafast transmission electron microscope is presented, based on a thermionic gun geometry. Utilizing an additional magnetic lens between the electron acceleration and the nominal condenser lens system, a larger percentage of the electrons created at the cathode are delivered to the specimen without degrading temporal, spatial and energy resolution significantly, while at the same time maintaining the femtosecond temporal resolution. Using the photon-induced near field electron microscopy effect (PINEM) on silver nanowires the cross-correlation between the light and electron pulses was measured, showing the impact of the gun settings and initiating laser pulse duration on the electron bunch properties. Tuneable electron pulses between 300 fs and several ps can be obtained, and an overall energy resolution around 1 eV was achieved

  8. Bridge- and Solvent-Mediated Intramolecular Electronic Communications in Ubiquinone-Based Biomolecular Wires

    Science.gov (United States)

    Liu, Xiao-Yuan; Ma, Wei; Zhou, Hao; Cao, Xiao-Ming; Long, Yi-Tao

    2015-05-01

    Intramolecular electronic communications of molecular wires play a crucial role for developing molecular devices. In the present work, we describe different degrees of intramolecular electronic communications in the redox processes of three ubiquinone-based biomolecular wires (Bis-CoQ0s) evaluated by electrochemistry and Density Functional Theory (DFT) methods in different solvents. We found that the bridges linkers have a significant effect on the electronic communications between the two peripheral ubiquinone moieties and solvents effects are limited and mostly depend on the nature of solvents. The DFT calculations for the first time indicate the intensity of the electronic communications during the redox processes rely on the molecular orbital elements VL for electron transfer (half of the energy splitting of the LUMO and LUMO+1), which is could be affected by the bridges linkers. The DFT calculations also demonstrates the effect of solvents on the latter two-electron transfer of Bis-CoQ0s is more significant than the former two electrons transfer as the observed electrochemical behaviors of three Bis-CoQ0s. In addition, the electrochemistry and theoretical calculations reveal the intramolecular electronic communications vary in the four-electron redox processes of three Bis-CoQ0s.

  9. Opto-electronic transport properties of graphene oxide based devices

    Energy Technology Data Exchange (ETDEWEB)

    Das, Poulomi; Ibrahim, Sk; Pal, Tanusri, E-mail: tanusri.pal@gmail.com [Department of Physics, Midnapore College, Midnapore-721101 (India); Chakraborty, Koushik; Ghosh, Surajit [Department of Physics & Technophysics, Vidyasagar University, Midnapore-721102 (India)

    2015-06-24

    Large area, solution-processed, graphene oxide (GO)nanocomposite based photo FET has been successfully fabricated. The device exhibits p-type charge transport characteristics in dark condition. Our measurements indicate that the transport characteristics are gate dependent and extremely sensitive to solar light. Photo current decay mechanism of GO is well explained and is associated with two phenomena: a) fast response process and b) slow response process. Slow response photo decay can be considered as the intrinsic phenomena which are present for both GO and reduced GO (r-GO), whereas the first response photo decay is controlled by the surface defect states. Demonstration of photo FET performance of GO thin film is a significant step forward in integrating these devices in various optoelectronic circuits.

  10. Role of defects in III-nitride based electronics

    Energy Technology Data Exchange (ETDEWEB)

    HAN,JUNG; MYERS JR.,SAMUEL M.; FOLLSTAEDT,DAVID M.; WRIGHT,ALAN F.; CRAWFORD,MARY H.; LEE,STEPHEN R.; SEAGER,CARLETON H.; SHUL,RANDY J.; BACA,ALBERT G.

    2000-01-01

    The LDRD entitled ``Role of Defects in III-Nitride Based Devices'' is aimed to place Sandia National Laboratory at the forefront of the field of GaN materials and devices by establishing a scientific foundation in areas such as material growth, defect characterization/modeling, and processing (metalization and etching) chemistry. In this SAND report the authors summarize their studies such as (1) the MOCVD growth and doping of GaN and AlGaN, (2) the characterization and modeling of hydrogen in GaN, including its bonding, diffusion, and activation behaviors, (3) the calculation of energetic of various defects including planar stacking faults, threading dislocations, and point defects in GaN, and (4) dry etching (plasma etching) of GaN (n- and p-types) and AlGaN. The result of the first AlGaN/GaN heterojunction bipolar transistor is also presented.

  11. Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection.

    Science.gov (United States)

    Bouchaala, Adam; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I

    2016-01-01

    The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming. PMID:27231914

  12. Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection.

    Science.gov (United States)

    Bouchaala, Adam; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I

    2016-01-01

    The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

  13. Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

    Directory of Open Access Journals (Sweden)

    Adam Bouchaala

    2016-05-01

    Full Text Available The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF, namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

  14. Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

    KAUST Repository

    Bouchaala, Adam

    2016-05-25

    The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

  15. Julius – a template based supplementary electronic health record system

    Directory of Open Access Journals (Sweden)

    Klein Gunnar O

    2007-05-01

    Full Text Available Abstract Background EHR systems are widely used in hospitals and primary care centres but it is usually difficult to share information and to collect patient data for clinical research. This is partly due to the different proprietary information models and inconsistent data quality. Our objective was to provide a more flexible solution enabling the clinicians to define which data to be recorded and shared for both routine documentation and clinical studies. The data should be possible to reuse through a common set of variable definitions providing a consistent nomenclature and validation of data. Another objective was that the templates used for the data entry and presentation should be possible to use in combination with the existing EHR systems. Methods We have designed and developed a template based system (called Julius that was integrated with existing EHR systems. The system is driven by the medical domain knowledge defined by clinicians in the form of templates and variable definitions stored in a common data repository. The system architecture consists of three layers. The presentation layer is purely web-based, which facilitates integration with existing EHR products. The domain layer consists of the template design system, a variable/clinical concept definition system, the transformation and validation logic all implemented in Java. The data source layer utilizes an object relational mapping tool and a relational database. Results The Julius system has been implemented, tested and deployed to three health care units in Stockholm, Sweden. The initial responses from the pilot users were positive. The template system facilitates patient data collection in many ways. The experience of using the template system suggests that enabling the clinicians to be in control of the system, is a good way to add supplementary functionality to the present EHR systems. Conclusion The approach of the template system in combination with various local EHR

  16. Modeling and the analysis of control logic for a digital PWM controller based on a nano electronic single electron transistor

    Directory of Open Access Journals (Sweden)

    Rathnakannan Kailasam

    2008-01-01

    Full Text Available This paper describes the modelling and the analysis of control logic for a Nano-Device- based PWM controller. A comprehensive simple SPICE schematic model for Single Electron transistor has been proposed. The operation of basic Single Electron Transistor logic gates and SET flip flops were successfully designed and their performances analyzed. The proposed design for realizing the logic gates and flip-flops is used in constructing the PWM controller utilized for switching the buck converter circuit. The output of the converter circuit is compared with reference voltage, and when the error voltage and the reference are matched the latch is reset so as to generate the PWM signal. Due to the simplicity and accuracy of the compact model, the simulation time and speed are much faster, which makes it potentially applicable in large-scale circuit simulation. This study confirms that the SET-based PWM controller is small in size, consumes ultra low power and operates at high speeds without compromising any performance. In addition these devices are capable of measuring charges of extremely high sensitivity.

  17. Fiber-based generator for wearable electronics and mobile medication.

    Science.gov (United States)

    Zhong, Junwen; Zhang, Yan; Zhong, Qize; Hu, Qiyi; Hu, Bin; Wang, Zhong Lin; Zhou, Jun

    2014-06-24

    Smart garments for monitoring physiological and biomechanical signals of the human body are key sensors for personalized healthcare. However, they typically require bulky battery packs or have to be plugged into an electric plug in order to operate. Thus, a smart shirt that can extract energy from human body motions to run body-worn healthcare sensors is particularly desirable. Here, we demonstrated a metal-free fiber-based generator (FBG) via a simple, cost-effective method by using commodity cotton threads, a polytetrafluoroethylene aqueous suspension, and carbon nanotubes as source materials. The FBGs can convert biomechanical motions/vibration energy into electricity utilizing the electrostatic effect with an average output power density of ∼0.1 μW/cm(2) and have been identified as an effective building element for a power shirt to trigger a wireless body temperature sensor system. Furthermore, the FBG was demonstrated as a self-powered active sensor to quantitatively detect human motion. PMID:24766072

  18. Global Ocean Surveillance With Electronic Intelligence Based Satellite System

    Science.gov (United States)

    Venkatramanan, Haritha

    2016-07-01

    The objective of this proposal is to design our own ELINT based satellite system to detect and locate the target by using satellite Trilateration Principle. The target position can be found by measuring the radio signals arrived at three satellites using Time Difference of Arrival(TDOA) technique. To locate a target it is necessary to determine the satellite position. The satellite motion and its position is obtained by using Simplified General Perturbation Model(SGP4) in MATLAB. This SGP4 accepts satellite Two Line Element(TLE) data and returns the position in the form of state vectors. These state vectors are then converted into observable parameters and then propagated in space. This calculations can be done for satellite constellation and non - visibility periods can be calculated. Satellite Trilateration consists of three satellites flying in formation with each other. The satellite constellation design consists of three satellites with an inclination of 61.3° maintained at equal distances between each other. The design is performed using MATLAB and simulated to obtain the necessary results. The target's position can be obtained using the three satellites ECEF Coordinate system and its position and velocity can be calculated in terms of Latitude and Longitude. The target's motion is simulated to obtain the Speed and Direction of Travel.

  19. Confined State and Electronic Transport in an Artificial Graphene-Based Tunnel Junction

    Institute of Scientific and Technical Information of China (English)

    袁建辉; 张建军; 曾奇军; 张俊佩; 成泽

    2011-01-01

    Artificial graphene structures embedded in semiconductors could open novel routes for studies of electron interactions in 1ow-dimensional systems. We propose a way to manipulate the transport properties of massless Dirac fermions in an artificial graphene-based tunnel junction. Velocity-modulation control of electron wave propagation in the different regions can be regarded as velocity barriers. Transmission probability of electron is affected profoundly by this velocity barrier. We find that there is no confinement for Dirac electron as the velocity ratio ζ is less than 1, but when the velocity ratio is larger than 1 the confined state appears in the continuum band. These localized Dirac electrons may lead to the decreasing of transmission probability.

  20. A microwave chip-based beam splitter for low-energy guided electrons

    CERN Document Server

    Hammer, J; Weber, Ph; Hommelhoff, P

    2014-01-01

    We demonstrate the splitting of a low-energy electron beam by means of a microwave pseudopotential formed above a planar chip substrate. Beam splitting arises from smoothly transforming the transverse guiding potential for an electron beam from a single-well harmonic confinement into a double-well, thereby generating two separated output beams with $5\\,$mm lateral spacing. Efficient beam splitting is observed for electron kinetic energies up to $3\\,$eV, in excellent agreement with particle tracking simulations. Furthermore, we present a beam splitter potential that is numerically optimized towards coherent and adiabatic splitting of guided electron wave packets. Prospects for electron-based quantum matter-wave optics applications are discussed.

  1. Using a scanning microbeam and a CdZnTe array for nuclear reaction measurements of water diffusion into an adhesive resin

    Energy Technology Data Exchange (ETDEWEB)

    Gauntlett, F.E. [Department of Physics, School of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)]. E-mail: F.Gauntlett@surrey.ac.uk; Rihawy, M.S. [Department of Physics, School of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Clough, A.S. [Department of Physics, School of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Liljedahl, C.D.M. [Centre for Materials Surfaces and Structural Systems, School of Engineering, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Crocombe, A.D. [Centre for Materials Surfaces and Structural Systems, School of Engineering, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2006-08-15

    The reaction D({sup 3}He, p){alpha} has been used with a {sup 3}He microbeam to investigate water ingress into epoxy resin, used as a bonding agent between aluminium plates. To facilitate this for low beam currents ({approx}150 pA), a unique large solid angle CdZnTe detector array is described which has been designed and built at Surrey for in vacuo proton detection.

  2. Using a scanning microbeam and a CdZnTe array for nuclear reaction measurements of water diffusion into an adhesive resin

    International Nuclear Information System (INIS)

    The reaction D(3He, p)α has been used with a 3He microbeam to investigate water ingress into epoxy resin, used as a bonding agent between aluminium plates. To facilitate this for low beam currents (∼150 pA), a unique large solid angle CdZnTe detector array is described which has been designed and built at Surrey for in vacuo proton detection

  3. A Fair Off-Line Electronic Cash Scheme Based on Restrictive Partially Blind Signature

    Institute of Scientific and Technical Information of China (English)

    王常吉; 吴建平; 段海新

    2004-01-01

    A fair off-line electronic cash scheme was presented based on a provable secure restrictive partially blind signature.The scheme is more efficient than those of previous works as the expiry date and denomination information are embedded in the electronic cash,which alleviates the storage pressure for the bank to check double spending,and the bank need not use different public keys for different coin values,shops and users need not carry a list of bank's public keys to verify in their electronic wallet.The modular exponentiations are reduced for both the user and the bank by letting the trustee publish the public values with different structure as those of previous electronic cash schemes.The scheme security is based on the random oracle model and the decision Diffie-Hellman assumption.The scheme can be easily extended to multi-trustees and multi-banks using threshold cryptography.

  4. Unified Electronic Currency Based on the Fourth Party Platform Integrated Payment Service

    Science.gov (United States)

    Yong, Xu; Qiqi, Hu

    This paper presents a solution of unified e-currency based on the fourth party platform integrated payment service. The purpose of the paper is to solve the problem of distribution and resource-wasting caused by the lack of unified electronic currency, and to solve regulatory difficulties due to regulation size caused by a wide variety of e-currency. Methods: This article first analyzes the problems in the development of electronic money, and then proposes the concept of a unified electronic currency based on the fourth party platform integrated payment service. Besides, it proposes a unified mechanism and transaction procedures for unified e-currency, and analyzes the liquidation process, security and regulatory requirements, which are involved in using unified electronic currency.

  5. Red phosphorescent organic light-emitting diodes using pyridine based electron transport type triplet host materials

    International Nuclear Information System (INIS)

    Research highlights: → Pyridine based host material for red phosphorescent organic light emitting diode. → Device optimization at low doping concentration of 2%. → Simplified red phosphorescent organic light emitting diodes. - Abstract: Pyridine based electron transport type host materials were developed and their device performances were investigated according to doping concentration. The pyridine substituent was combined with a spirofluorenebenzofluorene core unit and a high quantum efficiency of 13.3% was achieved in red phosphorescent organic light-emitting diodes at a low doping concentration of 2%. A simple red device without any electron transport layer could be fabricated and a simple device without any electron transport layer showed better power efficiency than the standard device with an electron transport layer.

  6. Research on Electronic-nose Application Based on Wireless Sensor Networks

    International Nuclear Information System (INIS)

    The paper proposed a structure of Wireless Sensor Networks based Electronic-nose system to monitors air quality in the building. In the study, the authors researched a data processing algorithm: fuzzy neural network based on RBF(Radial Basis Function) network model, to quantitatively analyze the gas ingredient and put forward a routing protocol for the system

  7. Probing electronic coupling between adenine bases in RNA strands from synchrotron radiation circular dichroism experiments

    DEFF Research Database (Denmark)

    Nielsen, Lisbeth Munksgård; Hoffmann, Søren Vrønning; Nielsen, Steen Brøndsted

    2012-01-01

    Circular dichroism spectra (176–330 nm) of RNA adenine oligomers, (rA)n (n = 1–10, 12, 15, and 20), reveal electronic coupling between two bases in short strands. The number of interacting bases in long strands is more and larger than that reported previously for the corresponding DNA strands....

  8. Curation-Based Network Marketing: Strategies for Network Growth and Electronic Word-of-Mouth Diffusion

    Science.gov (United States)

    Church, Earnie Mitchell, Jr.

    2013-01-01

    In the last couple of years, a new aspect of online social networking has emerged, in which the strength of social network connections is based not on social ties but mutually shared interests. This dissertation studies these "curation-based" online social networks (CBN) and their suitability for the diffusion of electronic word-of-mouth…

  9. CMOS technology: a critical enabler for free-form electronics-based killer applications

    Science.gov (United States)

    Hussain, Muhammad M.; Hussain, Aftab M.; Hanna, Amir

    2016-05-01

    Complementary metal oxide semiconductor (CMOS) technology offers batch manufacturability by ultra-large-scaleintegration (ULSI) of high performance electronics with a performance/cost advantage and profound reliability. However, as of today their focus has been on rigid and bulky thin film based materials. Their applications have been limited to computation, communication, display and vehicular electronics. With the upcoming surge of Internet of Everything, we have critical opportunity to expand the world of electronics by bridging between CMOS technology and free form electronics which can be used as wearable, implantable and embedded form. The asymmetry of shape and softness of surface (skins) in natural living objects including human, other species, plants make them incompatible with the presently available uniformly shaped and rigidly structured today's CMOS electronics. But if we can break this barrier then we can use the physically free form electronics for applications like plant monitoring for expansion of agricultural productivity and quality, we can find monitoring and treatment focused consumer healthcare electronics - and many more creative applications. In our view, the fundamental challenge is to engage the mass users to materialize their creative ideas. Present form of electronics are too complex to understand, to work with and to use. By deploying game changing additive manufacturing, low-cost raw materials, transfer printing along with CMOS technology, we can potentially stick high quality CMOS electronics on any existing objects and embed such electronics into any future objects that will be made. The end goal is to make them smart to augment the quality of our life. We use a particular example on implantable electronics (brain machine interface) and its integration strategy enabled by CMOS device design and technology run path.

  10. CMOS technology: a critical enabler for free-form electronics-based killer applications

    KAUST Repository

    Hussain, Muhammad Mustafa

    2016-05-17

    Complementary metal oxide semiconductor (CMOS) technology offers batch manufacturability by ultra-large-scaleintegration (ULSI) of high performance electronics with a performance/cost advantage and profound reliability. However, as of today their focus has been on rigid and bulky thin film based materials. Their applications have been limited to computation, communication, display and vehicular electronics. With the upcoming surge of Internet of Everything, we have critical opportunity to expand the world of electronics by bridging between CMOS technology and free form electronics which can be used as wearable, implantable and embedded form. The asymmetry of shape and softness of surface (skins) in natural living objects including human, other species, plants make them incompatible with the presently available uniformly shaped and rigidly structured today’s CMOS electronics. But if we can break this barrier then we can use the physically free form electronics for applications like plant monitoring for expansion of agricultural productivity and quality, we can find monitoring and treatment focused consumer healthcare electronics – and many more creative applications. In our view, the fundamental challenge is to engage the mass users to materialize their creative ideas. Present form of electronics are too complex to understand, to work with and to use. By deploying game changing additive manufacturing, low-cost raw materials, transfer printing along with CMOS technology, we can potentially stick high quality CMOS electronics on any existing objects and embed such electronics into any future objects that will be made. The end goal is to make them smart to augment the quality of our life. We use a particular example on implantable electronics (brain machine interface) and its integration strategy enabled by CMOS device design and technology run path. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is

  11. The research on electronic commerce security payment system based on set protocol

    Science.gov (United States)

    Guo, Hongliang

    2012-04-01

    With the rapid development of network technology, online transactions have become more and more common. In this paper, we firstly introduce the principle and the basic principal and technical foundation of SET, and then we analyze the progress of designing a system in the foundation of the procedure of the electronic business based on SET. On this basis, we design a system of the Payment System for Electronic Business. It will not only take on crucial realism signification for large-scale, medium-sized and mini-type corporations, but also provide guide meaning with programmer and design-developer to realize Electronic Commerce (EC).

  12. Laser-based X-ray and electron source for X-ray fluorescence studies

    Science.gov (United States)

    Valle Brozas, F.; Crego, A.; Roso, L.; Peralta Conde, A.

    2016-08-01

    In this work, we present a modification to conventional X-rays fluorescence using electrons as excitation source and compare it with the traditional X-ray excitation for the study of pigments. For this purpose, we have constructed a laser-based source capable to produce X-rays as well as electrons. Because of the large penetration depth of X-rays, the collected fluorescence signal is a combination of several material layers of the artwork under study. However, electrons are stopped in the first layers, allowing a more superficial analysis. We show that the combination of both excitation sources can provide extremely valuable information about the structure of the artwork.

  13. Hot-electron-based solar energy conversion with metal-semiconductor nanodiodes.

    Science.gov (United States)

    Lee, Young Keun; Lee, Hyosun; Lee, Changhwan; Hwang, Euyheon; Park, Jeong Young

    2016-06-29

    Energy dissipation at metal surfaces or interfaces between a metal and a dielectric generally results from elementary excitations, including phonons and electronic excitation, once external energy is deposited to the surface/interface during exothermic chemical processes or an electromagnetic wave incident. In this paper, we outline recent research activities to develop energy conversion devices based on hot electrons. We found that photon energy can be directly converted to hot electrons and that hot electrons flow through the interface of metal-semiconductor nanodiodes where a Schottky barrier is formed and the energy barrier is much lower than the work function of the metal. The detection of hot electron flow can be successfully measured using the photocurrent; we measured the photoyield of photoemission with incident photons-to-current conversion efficiency (IPCE). We also show that surface plasmons (i.e. the collective oscillation of conduction band electrons induced by interaction with an electromagnetic field) are excited on a rough metal surface and subsequently decay into secondary electrons, which gives rise to enhancement of the IPCE. Furthermore, the unique optical behavior of surface plasmons can be coupled with dye molecules, suggesting the possibility for producing additional channels for hot electron generation. PMID:27168177

  14. SEM technique for imaging and measuring electronic transport in nanocomposites based on electric field induced contrast

    Science.gov (United States)

    Jesse, Stephen [Knoxville, TN; Geohegan, David B [Knoxville, TN; Guillorn, Michael [Brooktondale, NY

    2009-02-17

    Methods and apparatus are described for SEM imaging and measuring electronic transport in nanocomposites based on electric field induced contrast. A method includes mounting a sample onto a sample holder, the sample including a sample material; wire bonding leads from the sample holder onto the sample; placing the sample holder in a vacuum chamber of a scanning electron microscope; connecting leads from the sample holder to a power source located outside the vacuum chamber; controlling secondary electron emission from the sample by applying a predetermined voltage to the sample through the leads; and generating an image of the secondary electron emission from the sample. An apparatus includes a sample holder for a scanning electron microscope having an electrical interconnect and leads on top of the sample holder electrically connected to the electrical interconnect; a power source and a controller connected to the electrical interconnect for applying voltage to the sample holder to control the secondary electron emission from a sample mounted on the sample holder; and a computer coupled to a secondary electron detector to generate images of the secondary electron emission from the sample.

  15. Hot-electron-based solar energy conversion with metal–semiconductor nanodiodes

    Science.gov (United States)

    Lee, Young Keun; Lee, Hyosun; Lee, Changhwan; Hwang, Euyheon; Park, Jeong Young

    2016-06-01

    Energy dissipation at metal surfaces or interfaces between a metal and a dielectric generally results from elementary excitations, including phonons and electronic excitation, once external energy is deposited to the surface/interface during exothermic chemical processes or an electromagnetic wave incident. In this paper, we outline recent research activities to develop energy conversion devices based on hot electrons. We found that photon energy can be directly converted to hot electrons and that hot electrons flow through the interface of metal–semiconductor nanodiodes where a Schottky barrier is formed and the energy barrier is much lower than the work function of the metal. The detection of hot electron flow can be successfully measured using the photocurrent; we measured the photoyield of photoemission with incident photons-to-current conversion efficiency (IPCE). We also show that surface plasmons (i.e. the collective oscillation of conduction band electrons induced by interaction with an electromagnetic field) are excited on a rough metal surface and subsequently decay into secondary electrons, which gives rise to enhancement of the IPCE. Furthermore, the unique optical behavior of surface plasmons can be coupled with dye molecules, suggesting the possibility for producing additional channels for hot electron generation.

  16. Hot-electron-based solar energy conversion with metal-semiconductor nanodiodes.

    Science.gov (United States)

    Lee, Young Keun; Lee, Hyosun; Lee, Changhwan; Hwang, Euyheon; Park, Jeong Young

    2016-06-29

    Energy dissipation at metal surfaces or interfaces between a metal and a dielectric generally results from elementary excitations, including phonons and electronic excitation, once external energy is deposited to the surface/interface during exothermic chemical processes or an electromagnetic wave incident. In this paper, we outline recent research activities to develop energy conversion devices based on hot electrons. We found that photon energy can be directly converted to hot electrons and that hot electrons flow through the interface of metal-semiconductor nanodiodes where a Schottky barrier is formed and the energy barrier is much lower than the work function of the metal. The detection of hot electron flow can be successfully measured using the photocurrent; we measured the photoyield of photoemission with incident photons-to-current conversion efficiency (IPCE). We also show that surface plasmons (i.e. the collective oscillation of conduction band electrons induced by interaction with an electromagnetic field) are excited on a rough metal surface and subsequently decay into secondary electrons, which gives rise to enhancement of the IPCE. Furthermore, the unique optical behavior of surface plasmons can be coupled with dye molecules, suggesting the possibility for producing additional channels for hot electron generation.

  17. Concept of a multichannel spin-resolving electron analyzer based on Mott scattering

    Science.gov (United States)

    Strocov, Vladimir N.; Petrov, Vladimir N.; Dil, J. Hugo

    2015-01-01

    The concept of a multichannel electron spin detector based on optical imaging principles and Mott scattering (iMott) is presented. A multichannel electron image produced by a standard angle-resolving (photo) electron analyzer or microscope is re-imaged by an electrostatic lens at an accelerating voltage of 40 kV onto the Au target. Quasi-elastic electrons bearing spin asymmetry of the Mott scattering are imaged by magnetic lenses onto position-sensitive electron CCDs whose differential signals yield the multichannel spin asymmetry image. Fundamental advantages of this concept include acceptance of inherently divergent electron sources from the electron analyzer or microscope focal plane as well as small aberrations achieved by virtue of high accelerating voltages, as demonstrated by extensive ray-tracing analysis. The efficiency gain compared with the single-channel Mott detector can be a factor of more than 104 which opens new prospects of spin-resolved spectroscopies in application not only to standard bulk and surface systems (Rashba effect, topological insulators, etc.) but also to buried heterostructures. The simultaneous spin detection combined with fast CCD readout enables efficient use of the iMott detectors at X-ray free-electron laser facilities. PMID:25931087

  18. Impact of edge shape on the functionalities of graphene-based single-molecule electronics devices

    OpenAIRE

    Carrascal, D.; García-Suárez, Víctor M.; Ferrer, Jaime

    2012-01-01

    We present an ab initio analysis of the impact of edge shape and graphene-molecule anchor coupling on the electronic and transport functionalities of graphene-based molecular electronics devices. We analyze how Fano-like resonances, spin filtering, and negative differential resistance effects may or may not arise by modifying suitably the edge shapes and the terminating groups of simple organic molecules. We show that the spin filtering effect is a consequence of the magnetic behavior of zigz...

  19. Vertical Field Effect Transistor based on Graphene-WS2 Heterostructures for flexible and transparent electronics

    OpenAIRE

    Georgiou, Thanasis; Jalil, Rashid; Belle, Branson D.; Britnell, Liam; Gorbachev, Roman V.; Morozov, Sergey V.; Kim, Yong-Jin; Gholinia, Ali; Haigh, Sarah J.; Makarovsky, Oleg; Eaves, Laurence; Ponomarenko, Leonid A.; Geim, Andre K.; Novoselov, Kostya S.; Mishchenko, Artem

    2012-01-01

    The celebrated electronic properties of graphene have opened way for materials just one-atom-thick to be used in the post-silicon electronic era. An important milestone was the creation of heterostructures based on graphene and other two-dimensional (2D) crystals, which can be assembled in 3D stacks with atomic layer precision. These layered structures have already led to a range of fascinating physical phenomena, and also have been used in demonstrating a prototype field effect tunnelling tr...

  20. Neuromimetic Circuits with Synaptic Devices based on Strongly Correlated Electron Systems

    OpenAIRE

    Ha, Sieu D.; Shi, Jian; Meroz, Yasmine; Mahadevan, L.; Ramanathan, Shriram

    2014-01-01

    Strongly correlated electron systems such as the rare-earth nickelates (RNiO3, R = rare-earth element) can exhibit synapse-like continuous long term potentiation and depression when gated with ionic liquids; exploiting the extreme sensitivity of coupled charge, spin, orbital, and lattice degrees of freedom to stoichiometry. We present experimental real-time, device-level classical conditioning and unlearning using nickelate-based synaptic devices in an electronic circuit compatible with both ...

  1. Charging process of polyurethane based composites under electronic irradiation: Effects of cellulose fiber content

    Science.gov (United States)

    Hadjadj, Aomar; Jbara, Omar; Tara, Ahmed; Gilliot, Mickael; Dellis, Jean-Luc

    2013-09-01

    The study deals with the charging effect of polyurethanes-based composites reinforced with cellulose fibers, under electronic beam irradiation in a scanning electron microscope. The results indicate that the leakage current and the trapped charge as well as the kinetics of charging process significantly change beyond a critical concentration of 10% cellulose fibers. These features are correlated with the cellulose concentration-dependence of the electrical properties, specifically resistivity and capacitance, of the composite.

  2. Synthesis, structure, and opto-electronic properties of organic-based nanoscale heterojunctions

    OpenAIRE

    Cimrová Vĕra; Rezek Bohuslav; Čermák Jan; Kromka Alexander; Ledinský Martin; Hubík Pavel; Mareš Jiří; Purkrt Adam; Fejfar Antonín; Kočka Jan

    2011-01-01

    Abstract Enormous research effort has been put into optimizing organic-based opto-electronic systems for efficient generation of free charge carriers. This optimization is mainly due to typically high dissociation energy (0.1-1 eV) and short diffusion length (10 nm) of excitons in organic materials. Inherently, interplay of microscopic structural, chemical, and opto-electronic properties plays crucial role. We show that employing and combining advanced scanning probe techniques can provide us...

  3. A Design of Learning Management System for Electronic Secretary Based on Ubiquitous Learning

    Directory of Open Access Journals (Sweden)

    Guangran Liu

    2011-02-01

    Full Text Available The proposed ubiquitous computing creates a new calculation model. Ubiquitous learning based on ubiquitous computing is the trend of current study theory. This paper introduces the concept of ubiquitous learning, analyzes and summarizes its thoughts and main characteristics, constructs the model of a ubiquitous learning environment. With the guidance of constructed ubiquitous learning environment model, we design the management system for electronic course-lattice, and use the metaphor of secretary naming the management system as electronic secretary.

  4. Agent-based inter-organizational workflow management system for electronic institutions

    OpenAIRE

    Leitão, Paulo; Mendes, João M.

    2008-01-01

    Indexado Inspec An Electronic Institution is a computational framework that provides a set of services supporting the Virtual Organization lifecycle, namely its formation, operation and dissolution. A crucial service is related to the coordination of the corresponding inter-organizational workflow defined by the established contract. This paper introduces an agent-based interorganizational workflow management system, part of an Electronic Institution, aiming to coordinate the contract exec...

  5. pi-Stacks Based on Self-Assembled Perylene Bisimides : Structural, Optical, and Electronic Properties

    OpenAIRE

    Chen, Zhijian

    2006-01-01

    As a traditional industrial pigment, perylene bisimide (PBI) dyes have found wide-spread applications. In addition, PBI dyes have been considered as versatile and promising functional materials for organic-based electronic and optic devices, such as transistors and solar cells. For these novel demands, the control of self-organization of this type of dye and the investigation of the relationship between the supramolecular structure and the relevant optical and electronic properties is of grea...

  6. Fabrication techniques and applications of flexible graphene-based electronic devices

    Science.gov (United States)

    Luqi, Tao; Danyang, Wang; Song, Jiang; Ying, Liu; Qianyi, Xie; He, Tian; Ningqin, Deng; Xuefeng, Wang; Yi, Yang; Tian-Ling, Ren

    2016-04-01

    In recent years, flexible electronic devices have become a hot topic of scientific research. These flexible devices are the basis of flexible circuits, flexible batteries, flexible displays and electronic skins. Graphene-based materials are very promising for flexible electronic devices, due to their high mobility, high elasticity, a tunable band gap, quantum electronic transport and high mechanical strength. In this article, we review the recent progress of the fabrication process and the applications of graphene-based electronic devices, including thermal acoustic devices, thermal rectifiers, graphene-based nanogenerators, pressure sensors and graphene-based light-emitting diodes. In summary, although there are still a lot of challenges needing to be solved, graphene-based materials are very promising for various flexible device applications in the future. Project supported by the National Natural Science Foundation of China (Nos. 60936002, 61025021, 61434001, 61574083), the State Key Development Program for Basic Research of China (No. 2015CB352100), the National Key Project of Science and Technology (No. 2011ZX02403-002) and the Special Fund for Agroscientific Research in the Public Interest of China (No. 201303107). M.A.M is additionally supported by the Postdoctoral Fellowship (PDF) Program of the Natural Sciences and Engineering Research Council (NSERC) of Canada and China's Postdoctoral Science Foundation (CPSF).

  7. High-Current Gain Two-Dimensional MoS₂-Base Hot-Electron Transistors.

    Science.gov (United States)

    Torres, Carlos M; Lan, Yann-Wen; Zeng, Caifu; Chen, Jyun-Hong; Kou, Xufeng; Navabi, Aryan; Tang, Jianshi; Montazeri, Mohammad; Adleman, James R; Lerner, Mitchell B; Zhong, Yuan-Liang; Li, Lain-Jong; Chen, Chii-Dong; Wang, Kang L

    2015-12-01

    The vertical transport of nonequilibrium charge carriers through semiconductor heterostructures has led to milestones in electronics with the development of the hot-electron transistor. Recently, significant advances have been made with atomically sharp heterostructures implementing various two-dimensional materials. Although graphene-base hot-electron transistors show great promise for electronic switching at high frequencies, they are limited by their low current gain. Here we show that, by choosing MoS2 and HfO2 for the filter barrier interface and using a noncrystalline semiconductor such as ITO for the collector, we can achieve an unprecedentedly high-current gain (α ∼ 0.95) in our hot-electron transistors operating at room temperature. Furthermore, the current gain can be tuned over 2 orders of magnitude with the collector-base voltage albeit this feature currently presents a drawback in the transistor performance metrics such as poor output resistance and poor intrinsic voltage gain. We anticipate our transistors will pave the way toward the realization of novel flexible 2D material-based high-density, low-energy, and high-frequency hot-carrier electronic applications. PMID:26524388

  8. High-Current Gain Two-Dimensional MoS 2 -Base Hot-Electron Transistors

    KAUST Repository

    Torres, Carlos M.

    2015-12-09

    The vertical transport of nonequilibrium charge carriers through semiconductor heterostructures has led to milestones in electronics with the development of the hot-electron transistor. Recently, significant advances have been made with atomically sharp heterostructures implementing various two-dimensional materials. Although graphene-base hot-electron transistors show great promise for electronic switching at high frequencies, they are limited by their low current gain. Here we show that, by choosing MoS2 and HfO2 for the filter barrier interface and using a noncrystalline semiconductor such as ITO for the collector, we can achieve an unprecedentedly high-current gain (α ∼ 0.95) in our hot-electron transistors operating at room temperature. Furthermore, the current gain can be tuned over 2 orders of magnitude with the collector-base voltage albeit this feature currently presents a drawback in the transistor performance metrics such as poor output resistance and poor intrinsic voltage gain. We anticipate our transistors will pave the way toward the realization of novel flexible 2D material-based high-density, low-energy, and high-frequency hot-carrier electronic applications. © 2015 American Chemical Society.

  9. Studies of Bystander Effects in 3-D Tissue Systems Using a Low-LET Microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, David J.

    2009-07-17

    frequency was also observed. When cells were cultured in medium donated from cells exposed to 5 Gy X-rays, a significant bystander effect was observed for clonogenic survival. When cells were cultured for 5 h with supernatant from donor cells exposed to 2 cGy and were then irradiated with 4 Gy X-rays, they failed to show an increase in survival compared with cells directly irradiated with 4 Gy. However, a twofold reduction in the oncogenic transformation frequency was seen. An adaptive dose of X-rays cancelled out the majority of the bystander effect produced by alpha-particles. For oncogenic transformation, but not cell survival, radioadaption can occur in unirradiated cells via a transmissible factor(s). A pilot study was undertaken to observe the bystander effect in a realistic multicellular three-dimensional morphology. We found bystander responses in a three-dimensional, normal human-tissue system. Endpoints were induction of micronucleated and apoptotic cells. A charged-particle microbeam was used, allowing irradiation of cells in defined locations in the tissue yet guaranteeing that no cells located more than a few micrometers away receive any radiation exposure. Unirradiated cells up to 1 mm distant from irradiated cells showed a significant enhancement in effect over background, with an average increase in effect of 1.7-fold for micronuclei and 2.8-fold for apoptosis. The surprisingly long range of bystander signals in human tissue suggests that bystander responses may be important in extrapolating radiation risk estimates from epidemiologically accessible doses down to very low doses where nonhit bystander cells will predominate. Finally, it would be of great benefit to develop a reproducible tissue system suitable for critical radiobiological assays. We have developed a reliable protocol to harvest cells from tissue samples and to investigate the damage induced on a single cell basis. In order to result in a valid tool for bystander experiments, the method

  10. Optical Absorption and Electron Injection of 4-(Cyanomethylbenzoic Acid Based Dyes: A DFT Study

    Directory of Open Access Journals (Sweden)

    Yuehua Zhang

    2015-01-01

    Full Text Available Density functional theory (DFT and time-dependent density functional theory (TDDFT calculations were carried out to study the ground state geometries, electronic structures, and absorption spectra of 4-(cyanomethylbenzoic acid based dyes (AG1 and AG2 used for dye-sensitized solar cells (DSSCs. The excited states properties and the thermodynamical parameters of electron injection were studied. The results showed that (a two dyes have uncoplanar structures along the donor unit and conjugated bridge space, (b two sensitizers exhibited intense absorption in the UV-Vis region, and (c the excited state oxidation potential was higher than the conduction band edge of TiO2 photoanode. As a result, a solar cell based on the 4-(cyanomethylbenzoic acid based dyes exhibited well photovoltaic performance. Furthermore, nine dyes were designed on the basis of AG1 and AG2 to improve optical response and electron injection.

  11. Broadband Single-Shot Electron Spectrometer for GeV-Class Laser Plasma Based Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, K.; Wan, W.; Ybarrolaza, N.; Syversrud, D.; Wallig, J.; Leemans, W.P.

    2008-05-01

    Laser-plasma-based accelerators can provide electrons over a broad energy range and/or with large momentum spread. The electron beam energy distribution can be controlled via accurate control of laser and plasma properties, and beams with energies ranging from'0.5 to 1000 MeV have been observed. Measuring these energy distributions in a single shot requires the use of a diagnostic with large momentum acceptance and, ideally, sufficient resolution to accurately measure energy spread in the case of narrow energy spread. Such a broadband single-shot electron magnetic spectrometer for GeV-class laser-plasma-based accelerators has been developed at Lawrence Berkeley National Laboratory. A detailed description of the hardware and the design concept is presented, as well as a performance evaluation of the spectrometer. The spectrometer covered electron beam energies raging from 0.01 to 1.1 GeV in a single shot, and enabled the simultaneous measurement of the laser properties at the exit of the accelerator through the use of a sufficiently large pole gap. Based on measured field maps and 3rd-order transport analysis, a few percent-level resolution and determination of the absolute energy were achieved over the entire energy range. Laser-plasma-based accelerator experiments demonstrated the capability of the spectrometer as a diagnostic and its suitability for such a broadband electron source.

  12. Semiconductor-based, large-area, flexible, electronic devices on {110}<100> oriented substrates

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, Amit

    2014-08-05

    Novel articles and methods to fabricate the same resulting in flexible, oriented, semiconductor-based, electronic devices on {110}<100> textured substrates are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

  13. [100] or [110] aligned, semiconductor-based, large-area, flexible, electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, Amit

    2015-03-24

    Novel articles and methods to fabricate the same resulting in flexible, large-area, [100] or [110] textured, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

  14. A Flexible Fiber-Based Supercapacitor-Triboelectric-Nanogenerator Power System for Wearable Electronics.

    Science.gov (United States)

    Wang, Jie; Li, Xiuhan; Zi, Yunlong; Wang, Sihong; Li, Zhaoling; Zheng, Li; Yi, Fang; Li, Shengming; Wang, Zhong Lin

    2015-09-01

    A flexible self-charging power system is built by integrating a fiber-based supercapacitor with a fiber-based triboelectric nanogenerator for harvesting mechanical energy from human motion. The fiber-based supercapacitor exhibits outstanding electrochemical properties, owing to the excellent pseudocapacitance of well-prepared RuO2 ·xH2 O by a vapor-phase hydrothermal method as the active material. The approach is a step forward toward self-powered wearable electronics. PMID:26175123

  15. Engineering design of dosimeter prototype based on graphite calorimetry for electron radiation dose measurement

    International Nuclear Information System (INIS)

    he engineering design of a dosimeter prototype based on graphite calorimetry for electron radiation dose measurement at electron energy of at most 300 keV and maximum dose of 60 kGy have been carried out. The graphite core is a cylinder shape with diameter and thickness of 30 mm and 2 mm respectively, surrounded by a guard ring made of the same graphite material. Dosimeter based on graphite calorimetry is equipped with a styrofoam for thermal insulation, temperature sensors and instrumentation based on micro controller. The characteristics of dosimeter based on graphite calorimetry are obtained by means of calculation and computer simulations using Penelope 2003 software and ANSYS computer program. The dosimeter based on graphite calorimetry has been designed to perform real time measurement of the average of absorbed and surface dose, it was expected that dosimeter based on graphite calorimetry can operate well. Compared with the cellulose tri acetate (CTA) dose measurement it gives relative differences of 18.9% and 9.1% at the experiments of energy variation and electron beam current alteration of the electron beam machine (EBM) respectively. (author

  16. Design of a proton-electron beam overlap monitor for the new RHIC electron lens, based on detecting energetic backscattered electrons

    Energy Technology Data Exchange (ETDEWEB)

    Thieberger T.; Beebe, E.; Fischer, W.; Gassner, D.; Gu, X.; Hamdi, K.; Hock, J.; Minty, M.; Miller, T.; Montag, C.; Pikin, A.

    2012-04-15

    The optimal performance of the two electron lenses that are being implemented for high intensity polarized proton operation of RHIC requires excellent collinearity of the {approx}0.3 mm RMS wide electron beams with the proton bunch trajectories over the {approx}2m interaction lengths. The main beam overlap diagnostic tool will make use of electrons backscattered in close encounters with the relativistic protons. These electrons will spiral along the electron guiding magnetic field and will be detected in a plastic scintillator located close to the electron gun. A fraction of these electrons will have energies high enough to emerge from the vacuum chamber through a thin window thus simplifying the design and operation of the detector. The intensity of the detected electrons provides a measure of the overlap between the e- and the opposing proton beams. Joint electron arrival time and energy discrimination may be used additionally to gain some longitudinal position information with a single detector per lens.

  17. Developing an Accelerator Driven System (ADS) based on electron accelerators and heavy water

    International Nuclear Information System (INIS)

    An ADS based on electron accelerators has been developed specifically for energy generation and medical applications. Monte Carlo simulations have been performed using FLUKA code to design a hybrid electron target and the core components. The composition, geometry of conversion targets and the coolant system have been optimized for electron beam energies of 20 to 100 MeV . Furthermore, the photon and photoneutron energy spectra, distribution and energy deposition for various incoming electron beam powers have been studied. Light-heavy water of various mixtures have been used as heat removal for the targets, as γ−n converters and as neutron moderators. We have shown that an electron LINAC, as a neutron production driver for ADSs, is capable of producing a neutron output of > 3.5 × 1014 (n/s/mA). Accordingly, the feasibility of an electron-based ADS employing the designed features is promising for energy generation and high intense neutron production which have various applications such as medical therapies

  18. Developing an Accelerator Driven System (ADS) based on electron accelerators and heavy water

    Science.gov (United States)

    Feizi, H.; Ranjbar, A. H.

    2016-02-01

    An ADS based on electron accelerators has been developed specifically for energy generation and medical applications. Monte Carlo simulations have been performed using FLUKA code to design a hybrid electron target and the core components. The composition, geometry of conversion targets and the coolant system have been optimized for electron beam energies of 20 to 100 MeV . Furthermore, the photon and photoneutron energy spectra, distribution and energy deposition for various incoming electron beam powers have been studied. Light-heavy water of various mixtures have been used as heat removal for the targets, as γ-n converters and as neutron moderators. We have shown that an electron LINAC, as a neutron production driver for ADSs, is capable of producing a neutron output of > 3.5 × 1014 (n/s/mA). Accordingly, the feasibility of an electron-based ADS employing the designed features is promising for energy generation and high intense neutron production which have various applications such as medical therapies.

  19. Femtosecond electron and X-ray generation by laser and plasma-based sources

    International Nuclear Information System (INIS)

    The generation of ultra-short x-rays by Thomson scattering intense laser pulses from electron beams is discussed, including recent experimental results and methods for enhancing the x-ray flux. A high flux of x-rays in a femtosecond pulse requires the generation of femtosecond electron bunches and a head-on Thomson scattering geometry. The generation of ultrashort electron bunches in a plasma-based accelerator with an injection technique that uses two colliding laser pulses is discussed. Simulations indicate the bunches as short as a few fs can be produced. Conversion of the fs electron pulse to a fs x-ray pulse can be accomplished by Bremsstrahlung or Thomson scattering

  20. Radiative damping and electron beam dynamics in plasma-based accelerators.

    Science.gov (United States)

    Michel, P; Schroeder, C B; Shadwick, B A; Esarey, E; Leemans, W P

    2006-08-01

    The effects of radiation reaction on electron beam dynamics are studied in the context of plasma-based accelerators. Electrons accelerated in a plasma channel undergo transverse betatron oscillations due to strong focusing forces. These oscillations lead to emission by the electrons of synchrotron radiation, with a corresponding energy loss that affects the beam properties. An analytical model for the single particle orbits and beam moments including the classical radiation reaction force is derived and compared to the results of a particle transport code. Since the betatron amplitude depends on the initial transverse position of the electron, the resulting radiation can increase the relative energy spread of the beam to significant levels (e.g., several percent). This effect can be diminished by matching the beam into the channel, which could require micron sized beam radii for typical values of the beam emittance and plasma density.

  1. Radiative damping and electron beam dynamics in plasma-based accelerators

    Science.gov (United States)

    Michel, P.; Schroeder, C. B.; Shadwick, B. A.; Esarey, E.; Leemans, W. P.

    2006-08-01

    The effects of radiation reaction on electron beam dynamics are studied in the context of plasma-based accelerators. Electrons accelerated in a plasma channel undergo transverse betatron oscillations due to strong focusing forces. These oscillations lead to emission by the electrons of synchrotron radiation, with a corresponding energy loss that affects the beam properties. An analytical model for the single particle orbits and beam moments including the classical radiation reaction force is derived and compared to the results of a particle transport code. Since the betatron amplitude depends on the initial transverse position of the electron, the resulting radiation can increase the relative energy spread of the beam to significant levels (e.g., several percent). This effect can be diminished by matching the beam into the channel, which could require micron sized beam radii for typical values of the beam emittance and plasma density.

  2. Femtosecond electron and x-ray source based on laser wakefield accelerator

    CERN Document Server

    Oulianov, D A; Gosztola, D J; Korovyanko, O J; Li, Y; Rey de Castro, R C; Shkrob, I A; Crowell, Robert A.; Gosztola, David J.; Korovyanko, Oleg J.; Li, Yuelin; Oulianov, Dmitri A.; Rey-de-Castro, Roberto C.; Shkrob, Ilya A.

    2006-01-01

    A terawatt tabletop laser wakefield acceleration source of relativistic electrons has been developed in our Terawatt Ultrafast High Field Facility (TUHFF). The preliminary results for ultrafast radiolysis of liquid water using this femtosecond electron source are presented. A TUHFF based femtosecond x-ray source is proposed. Thomson scattering of the accelerated electrons off a counterpropagating terawatt laser beam will be used to generate keV x-ray photons. The expected parameters of this x-ray source have been estimated. The short pulse duration, high flux, and good collimation of the resulting x-ray beam would be conducive for ultrafast time-resolved x-ray absorption studies of short-lived transient species in gases, liquids, and solids. It is argued that the solvation dynamics of Br atoms generated in photoinduced electron detachment from aqueous bromide would make a convenient choice for the first pump-probe experiment using this x-ray source.

  3. Investigation on gradient material fabrication with electron beam melting based on scanning track control

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new electron beam control system was developed in a general vacuum electron beam machine by assembling with industrial control computer, programmable logic control (PLC), deflection coil, data acquisition card, power amplifier, etc. In this control system, scanning track and energy distribution of electron beam could be edited off-line, real-time adjusted and controlled on-line. Ti-Mo gradient material (GM) with high temperature resistant was fabricated using the technology of electron beam melting. The melting processes include three steps, such as preheating, melting, and homogenizing. The results show that the GM prepared by melting technology has fine appearance, and it has good integrated interface with the Ti alloy. Mo and Ti elements are gradually distributed in the interface of the gradient material. The microstructure close to the Ti alloy base metal is α+β basket-waver grain, and the microstructure close to the GM is a single phase of β solid solution.

  4. Study on Calibration System for Electronic Transformers Based on High-Accuracy PCI Card

    Directory of Open Access Journals (Sweden)

    Mingzhu Zhang

    2013-03-01

    Full Text Available With preliminary applying of Electronic Transformer (ET based on IEC 61850 standards in power grid, the calibrations of tested transformers have attracted extensive research attention. This study proposes a novel Calibration System of ET (CSET based on high-accuracy card. Data acquisition of ET and Standard Trans-former (ST is gotten by optic Ethernet and PCI-4462 data acquisition card, respectively. Meanwhile, the synchronized sampling between ET and ST is completed on the optic/electronic pulse signal of PCI synchronization card. The signals processing and human interface are realized by Labview software. The system proposed in the study is feasible for calibrating Electronic Voltage/Current Transformers (EVT/ECT of different voltage classes. System tests show that the precision of the system can get to 0.2°.

  5. Study on Calibration System for Electronic Transformers Based on High-Accuracy PCI Card

    Directory of Open Access Journals (Sweden)

    Mingzhu Zhang

    2013-05-01

    Full Text Available With preliminary applying of Electronic Transformer (ET based on IEC 61850 standards in power grid, the calibration of tested transformers has attracted extensive research attention. This study proposes a novel Calibration System of ET (CSET based on high-accuracy card. Data acquisition of ET and standard trans-former (ST is gotten by optic Ethernet and PCI-4462 data acquisition card, respectively. Meanwhile, the synchronized sampling between ET and ST is completed on the optic/electronic pulse signal of PCI synchronization card. The signals processing and human interface are realized by Lab view software. The system proposed in the study is feasible for calibrating Electronic Voltage/Current Transformers (EVT/ECT of different voltage classes. System tests show that the precision of the system can get to 0.2°.

  6. Efficient electronic coupling and improved stability with dithiocarbamate-based molecular junctions

    Science.gov (United States)

    von Wrochem, Florian; Gao, Deqing; Scholz, Frank; Nothofer, Heinz-Georg; Nelles, Gabriele; Wessels, Jurina M.

    2010-08-01

    Molecular electronic devices require stable and highly conductive contacts between the metal electrodes and molecules. Thiols and amines are widely used to attach molecules to metals, but they form poor electrical contacts and lack the robustness required for device applications. Here, we demonstrate that dithiocarbamates provide superior electrical contact and thermal stability when compared to thiols on metals. Ultraviolet photoelectron spectroscopy and density functional theory show the presence of electronic states at 0.6 eV below the Fermi level of Au, which effectively reduce the charge injection barrier across the metal-molecule interface. Charge transport measurements across oligophenylene monolayers reveal that the conductance of terphenyl-dithiocarbamate junctions is two orders of magnitude higher than that of terphenyl-thiolate junctions. The stability and low contact resistance of dithiocarbamate-based molecular junctions represent a significant step towards the development of robust, organic-based electronic circuits.

  7. High power THz source based on coherent radiation of picosecond relativistic electron bunch train

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Tunable and compact high power terahertz (THz) radiation based on coherent radiation (CR) of the picosecond relativistic electron bunch train is under development at the Tsinghua accelerator lab. Coherent synchronization radiation (CSR) and coherent transition radiation (CTR) are researched based on an S-band compact electron linac, a bending magnet or a thin foil. The bunch train’s form factors, which are the key factor of THz radiation, are analyzed by the PARMELA simulation. The effects of electron bunch trains under different conditions, such as the bunch number, bunch charges, micro-pulses inter-distance, and accelerating gradient of the gun are investigated separately in this paper. The optimal radiated THz power and spectra should take these factors as a whole into account.

  8. Verification of MLC based real-time tumor tracking using an electronic portal imaging device

    OpenAIRE

    Han-Oh, Sarah; Yi, Byong Yong; Lerma, Fritz; Berman, Barry L.; Gui, Minzhi; Yu, Cedric

    2010-01-01

    Purpose: The authors have developed a novel technique using an electronic portal imaging device (EPID) to verify the geometrical accuracy of delivery of dose-rate-regulated tracking (DRRT). This technique, called verification of real-time tracking with EPID (VORTE), can potentially be used for both on-line and off-line quality assurance (QA) of MLC-based dynamic tumor tracking.

  9. Mixing Problem Based Learning and Conventional Teaching Methods in an Analog Electronics Course

    Science.gov (United States)

    Podges, J. M.; Kommers, P. A. M.; Winnips, K.; van Joolingen, W. R.

    2014-01-01

    This study, undertaken at the Walter Sisulu University of Technology (WSU) in South Africa, describes how problem-based learning (PBL) affects the first year 'analog electronics course', when PBL and the lecturing mode is compared. Problems were designed to match real-life situations. Data between the experimental group and the control group that…

  10. DNA electronic circular dichroism on the inter-base pair scale

    DEFF Research Database (Denmark)

    Di Meo, Florent; Nørby, Morten Steen; Rubio-Magnieto, Jenifer;

    2015-01-01

    A successful elucidation of the near-ultraviolet electronic circular dichroism spectrum of a short double-stranded DNA is reported. Time-dependent density functional theory methods are shown to accurately predict spectra and assign bands on the microscopic base-pair scale, a finding that opens the...

  11. Mixing Problem Based Learning And Conventional Teaching Methods In An Analog Electronics Course

    NARCIS (Netherlands)

    Podges, J.M.; Kommers, P.A.M.; Winnips, K.; Joolingen, van W.R.

    2014-01-01

    This study, undertaken at the Walter Sisulu University of Technology (WSU) in South Africa, describes how problem-based learning (PBL) affects the first year ‘analog electronics course’, when PBL and the lecturing mode is compared. Problems were designed to match real-life situations. Data betwee

  12. Site selection of active damper for stabilizing power electronics based power distribution system

    DEFF Research Database (Denmark)

    Yoon, Changwoo; Wang, Xiongfei; Bak, Claus Leth;

    2015-01-01

    Stability in the nowadays distribution power system is endangered by interaction problems that may arise from newly added power-electronics based power devices. Recently, a new concept to deal with this higher frequency instability, the active damper, has been proposed. The active damper is a pow...

  13. PLC Control System Based on EPICS for 10 MeV Electron Linac

    Institute of Scientific and Technical Information of China (English)

    LIU; Bao-jie; ZHANG; Li-feng; ZHU; Zhi-bin

    2013-01-01

    Control system of the electron Linac using Distributed Control System(DCS)was studied here.The hardware of control system consists of siemens programmable logical controllers(PLCs)and industrial computers,and the software is developed based on experimental physics and industrial control system

  14. E-beam accelerator cavity development for the ground-based free electron laser

    Science.gov (United States)

    Bultman, N. K.; Spalek, G.

    Los Alamos National Laboratory is designing and developing four prototype accelerator cavities for high power testing on the Modular Component Technology Development (MCTD) test stand at Boeing. These cavities provide the basis for the e-beam accelerator hardware that will be used in the Ground Based Free Electron Laser (GBFEL) to be sited at the White Sands Missile Range (WSMR) in New Mexico.

  15. Efficacy of Simulation-Based Learning of Electronics Using Visualization and Manipulation

    Science.gov (United States)

    Chen, Yu-Lung; Hong, Yu-Ru; Sung, Yao-Ting; Chang, Kuo-En

    2011-01-01

    Software for simulation-based learning of electronics was implemented to help learners understand complex and abstract concepts through observing external representations and exploring concept models. The software comprises modules for visualization and simulative manipulation. Differences in learning performance of using the learning software…

  16. Optically or electronically steerable mm-wave phased antennas array based on semiconductor structure

    OpenAIRE

    Rogov, V. Ya.; Grinev, A. Yu.; Zaikin, A. E.

    1999-01-01

    This paper presents results of the complex researches of Phased Array Antennas (PAAs) for the MMW-band’s short-wave subband based on the nontraditional approach to designing the antenna’s aperture when using multilayer semiconductor structures with optically or electronically steerable electrophysical parameters.

  17. SPICE-NIRS microbeam: a focused vertical system for proton irradiation of a single cell for radiobiological research.

    Science.gov (United States)

    Konishi, Teruaki; Oikawa, Masakazu; Suya, Noriyoshi; Ishikawa, Takahiro; Maeda, Takeshi; Kobayashi, Alisa; Shiomi, Naoko; Kodama, Kumiko; Hamano, Tsuyoshi; Homma-Takeda, Shino; Isono, Mayu; Hieda, Kotaro; Uchihori, Yukio; Shirakawa, Yoshiyuki

    2013-07-01

    The Single Particle Irradiation system to Cell (SPICE) facility at the National Institute of Radiological Sciences (NIRS) is a focused vertical microbeam system designed to irradiate the nuclei of adhesive mammalian cells with a defined number of 3.4 MeV protons. The approximately 2-μm diameter proton beam is focused with a magnetic quadrupole triplet lens and traverses the cells contained in dishes from bottom to top. All procedures for irradiation, such as cell image capturing, cell recognition and position calculation, are automated. The most distinctive characteristic of the system is its stability and high throughput; i.e. 3000 cells in a 5 mm × 5 mm area in a single dish can be routinely irradiated by the 2-μm beam within 15 min (the maximum irradiation speed is 400 cells/min). The number of protons can be set as low as one, at a precision measured by CR-39 detectors to be 99.0%. A variety of targeting modes such as fractional population targeting mode, multi-position targeting mode for nucleus irradiation and cytoplasm targeting mode are available. As an example of multi-position targeting irradiation of mammalian cells, five fluorescent spots in a cell nucleus were demonstrated using the γ-H2AX immune-staining technique. The SPICE performance modes described in this paper are in routine use. SPICE is a joint-use research facility of NIRS and its beam times are distributed for collaborative research. PMID:23287773

  18. Investigation of Abscopal and Bystander Effects in Immunocompromised Mice After Exposure to Pencilbeam and Microbeam Synchrotron Radiation.

    Science.gov (United States)

    Fernandez-Palomo, Cristian; Schültke, Elisabeth; Bräuer-Krisch, Elke; Laissue, Jean Albert; Blattmann, Hans; Seymour, Colin; Mothersill, Carmel

    2016-08-01

    Out-of-field effects are of considerable interest in radiotherapy. The mechanisms are poorly understood but are thought to involve signaling processes, which induce responses in non-targeted cells and tissues. The immune response is thought to play a role. The goal of this research was to study the induction of abscopal effects in the bladders of NU-Foxn1 mice after irradiating their brains using Pencil Beam (PB) or microbeam (MRT) irradiation at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Athymic nude mice injected with F98 glioma cells into their right cerebral hemisphere 7 d earlier were treated with either MRT or PB. After recovery times of 2, 12, and 48 h, the urinary bladders were extracted and cultured as tissue explants for 24 h. The growth medium containing the potential signaling factors was harvested, filtered, and transferred to HaCaT reporter cells to assess their clonogenic survival and calcium signaling potential. The results show that in the tumor-free mice, both treatment modalities produce strong bystander/abscopal signals using the clonogenic reporter assay; however, the calcium data do not support a calcium channel mediated mechanism. The presence of a tumor reduces or reverses the effect. PB produced significantly stronger effects in the bladders of tumor-bearing animals. The authors conclude that immunocompromised mice produce signals, which can alter the response of unirradiated reporter cells; however, a novel mechanism appears to be involved. PMID:27356059

  19. Constraint-based modeling of carbon fixation and the energetics of electron transfer in Geobacter metallireducens.

    Directory of Open Access Journals (Sweden)

    Adam M Feist

    2014-04-01

    Full Text Available Geobacter species are of great interest for environmental and biotechnology applications as they can carry out direct electron transfer to insoluble metals or other microorganisms and have the ability to assimilate inorganic carbon. Here, we report on the capability and key enabling metabolic machinery of Geobacter metallireducens GS-15 to carry out CO2 fixation and direct electron transfer to iron. An updated metabolic reconstruction was generated, growth screens on targeted conditions of interest were performed, and constraint-based analysis was utilized to characterize and evaluate critical pathways and reactions in G. metallireducens. The novel capability of G. metallireducens to grow autotrophically with formate and Fe(III was predicted and subsequently validated in vivo. Additionally, the energetic cost of transferring electrons to an external electron acceptor was determined through analysis of growth experiments carried out using three different electron acceptors (Fe(III, nitrate, and fumarate by systematically isolating and examining different parts of the electron transport chain. The updated reconstruction will serve as a knowledgebase for understanding and engineering Geobacter and similar species.

  20. Electronic Chronic Disease Registers Based on Accreditation Standards for Family Medicine Teams

    OpenAIRE

    Valjevac, Salih; Ridjanovic, Zoran; Masic, Izet

    2009-01-01

    CONFLICT OF INTEREST: NONE DECLARED SUMMARY Agency for Quality and Accreditation of Federation of Bosnia and Herzegovina (AKAZ) has developed computer based chronic disease register based on the accreditation standards in order to facilitate maintenance of chronic disease registers in the absence of electronic health records, and to speed up and simplify calculation for over 70 clinical indicators from accreditation standards for family medicine teams. This article presents development of the...