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Sample records for optical potential approach

  1. Microscopic optical potential for 208Pb in the nuclear structure approach

    International Nuclear Information System (INIS)

    Bernard, V.; Nguyen Van Gai.

    1979-04-01

    The optical potential for nucleon- 208 Pb scattering below 30 MeV is calculated microscopically as the sum of a real Hartree-Fock term and a complex correction term arising from the coupling to excited states of the target. The Skyrme effective interaction is used to generate the Hartree-Fock field, the RPA excited states and the coupling. A complex local equivalent potential is defined and used to calculate scattering and absorption cross-sections. The real part of the optical potential is reasonably well described in this approach while the imaginary part is too weak. Inclusion of rearrangement processes could improve the agreement with experiment

  2. Nuclear structure approach to the calculation of the imaginary alpha-nucleus optical potential

    International Nuclear Information System (INIS)

    Dermawan, H.; Osterfeld, F.; Madsen, V.A.

    1981-01-01

    A microscopic calculation of the second-order imaginary optical potential for 40 (Ca(α,α) is made for incident energies of 31 and 100 MeV using RPA transition densities for intermediate excited states. The projectile is treated as an elementary particle, and the alpha-nucleon interaction is normalized by fitting 3 - inelastic cross sections with a folded M3Y potential. The use of an optical Green's function for the intermediate propagator is found to be important. Equivalent local potentials are obtained and used to calculate elastic scattering cross sections. Agreement with low-angle experimental data is fair at 31 MeV, but at 100 MeV the calculated cross sections indicate much too little absorption. 9 figures, 1 table

  3. Neutron optical potentials

    International Nuclear Information System (INIS)

    Wilmore, D.; Hodgson, P.E.

    1976-01-01

    The purpose of this paper is to provide a guide to the use of optical model computer programs to analyse and calculate neutron data. After a brief discussion of the physical basis of the optical model a survey is given of the most widely used optical model and Hauser-Feshbach computer programs. The range of applicability and reliability of the major optical potentials proposed is assessed by comparison with available experimental data and some observations and suggestions are made for the optimum choice of optical potentials for given purposes of neutron data calculations. (author)

  4. Three-body approach to the nucleon-nucleus optical potential

    International Nuclear Information System (INIS)

    Tandy, P.C.; Redish, E.F.; Bolle, D.

    1976-01-01

    In the Watson single scattering theory of the optical potential it is customary to approximate the propagation by two-body Green functions in order to simplify calculations. The reaction mechanism being described, however, is decidedly three-body in character. The central difficulty in building three-body models for nucleon-nucleus elastic scattering is to find the proper way of imbedding the superposed three-body reaction mechanism in the many-body problem without introducing serious overcounting effects. One would also like an explicit description of the intermediate state processes responsible for absorption. In this paper a three-body approximation to the optical potential theory is presented which overcomes the overcounting problem and is capable of including the following effects: (1) the proper kinematics of the struck nucleon, (2) its binding potential, (3) the identity of target nucleons, and (4) realistic wave functions and spectroscopic factors. The three-body model for the optical potential can be extended using unitarity methods to yield a unified three-body-like model of elastic scattering, pickup, and single nucleon knockout. (Auth.)

  5. Optical potential approach to the electron-atom impact ionization threshold problem

    Science.gov (United States)

    Temkin, A.; Hahn, Y.

    1973-01-01

    The problem of the threshold law for electron-atom impact ionization is reconsidered as an extrapolation of inelastic cross sections through the ionization threshold. The cross sections are evaluated from a distorted wave matrix element, the final state of which describes the scattering from the Nth excited state of the target atom. The actual calculation is carried for the e-H system, and a model is introduced which is shown to preserve the essential properties of the problem while at the same time reducing the dimensionability of the Schrodinger equation. Nevertheless, the scattering equation is still very complex. It is dominated by the optical potential which is expanded in terms of eigen-spectrum of QHQ. It is shown by actual calculation that the lower eigenvalues of this spectrum descend below the relevant inelastic thresholds; it follows rigorously that the optical potential contains repulsive terms. Analytical solutions of the final state wave function are obtained with several approximations of the optical potential.

  6. Convergence of an L2-approach in the coupled-channels optical potential method for e-H scattering

    International Nuclear Information System (INIS)

    Bray, I.; Konovalov, D.A.; McCarthy, I.E.

    1990-08-01

    An L 2 approach to the coupled-channels optical method is studied. The investigation is done for electron-hydrogen elastic scattering at projectile energies of 30, 50, 100 and 200 eV. Weak coupling, free-particle Green's function and no exchange in Q-space are appoximations used to calculate the polarization potential. This model problem is solved exactly using actual hydrogen discrete and continuum functions. The convergence of an L 2 approach with the Laguerre basis to the exact result is investigated. It is found that a basis of 10 Laguerre functions is sufficient for convergence of approximately 5% in the polarization potential matrix elements and 2% in the differential cross sections for non-large angles. The convergence is faster for smaller energies. In general, the convergence to the exact result is slow. 12 refs., 2 tabs., 2 figs

  7. Pion nucleus optical potential

    International Nuclear Information System (INIS)

    Kam, J. de.

    1981-01-01

    The main goal of the investigations, presented is to establish the contributions to the optical potential, coming from scattering processes which involve 1p-1h nuclear states in the intermediate scattering system. The effects of the Pauli principle corrections and the binding corrections are studied in detail. A phenomenological study of pion absorption effects is also presented. The calculations all concern π- 4 He scattering. The simplicity of the 4 He structure makes the π- 4 He system quite an ideal tool for studying the reaction mechanism. (Auth.)

  8. Neutron and proton optical potentials

    International Nuclear Information System (INIS)

    Hansen, L.F.

    1985-11-01

    The neutron and proton optical model potentials (OMP) are discussed in terms of microscopic (MOMP) and phenomenological (POMP) models. For the MOMP, two approaches are discussed, the nucleus matter approach [Jeukenne-Lejeune-Mahaux (JLM) and Brieva-Rook-von Geramb (BRVG), potentials] and the finite nuclei approach (Osterfeld and Madsen). For the POMP, the Lane charge-exchange potential and its validity over a wide mass range is reviewed. In addition to the Lane symmetry term, the Coulomb correction to both the real and imaginary parts of the OMP is discussed for the above models. The use of the OMP to calculate collective inelastic scattering and observed differences between the neutron- and proton-deformation parameters is also illustrated. 25 refs., 3 figs

  9. The deuteron microscopic optical potential

    International Nuclear Information System (INIS)

    Lu Congshan; Zhang Jingshang; Shen Qingbiao

    1991-01-01

    The two particle Green's function is introduced. When the direct interaction between two nucleons is neglected, the first and second order mass operators of two particles are the sum of those for each particle. The nucleon microscopic optical potential is calculated by applying nuclear matter approximation and effective Skyrme interaction. Then the deuteron microscopic optical potential (DMOP) is calculated by using fold formula. For improvement of the theory, the two particle polarization diagram contribution to the imaginary part of the deuteron microscopic optical potential is studied

  10. Deuteron microscopic optical model potential

    International Nuclear Information System (INIS)

    Guo Hairui; Han Yinlu; Shen Qingbiao; Xu Yongli

    2010-01-01

    A deuteron microscopic optical model potential is obtained by the Green function method through nuclear-matter approximation and local-density approximation based on the effective Skyrme interaction. The microscopic optical model potential is used to calculate the deuteron reaction cross sections and the elastic scattering angular distributions for some target nuclei in the mass range 6≤A≤208 with incident deuteron energies up to 200 MeV. The calculated results are compared with the experimental data.

  11. Isospin-dependent term in the relativistic microscopic optical potential

    International Nuclear Information System (INIS)

    Rong Jian; Ma Zhongyu; National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou; Chinese Academy of Sciences, Beijing

    2005-01-01

    The isospin-dependence of the relativistic microscopic optical potential is investigated in the Dirac Brueckner-Hartree-Fock approach. The isospin part of the microscopic optical potential is emphasized. A local density approximation is adopted for finite nuclei. Taking 208 Pb as example, the difference between proton and neutron optical potentials is studied and compared with the phenomenological Lane Model potential. (authors)

  12. The neutron optical model potential

    International Nuclear Information System (INIS)

    Hodgson, P.E.

    1989-01-01

    The present status of optical model calculations of neutron scattering and interactions is reviewed, with special emphasis on more recent developments and the more promising lines of research. The use of dispersion relations to provide an extra constraint on the potential is discussed, together with their application to studies of the Fermi surface anomaly. The application of potential inversion techniques to determine the form of the potential is also considered. (author). 39 refs, figs

  13. Energy dependence of nonlocal optical potentials

    Science.gov (United States)

    Lovell, A. E.; Bacq, P.-L.; Capel, P.; Nunes, F. M.; Titus, L. J.

    2017-11-01

    Recently, a variety of studies have shown the importance of including nonlocality in the description of reactions. The goal of this work is to revisit the phenomenological approach to determining nonlocal optical potentials from elastic scattering. We perform a χ2 analysis of neutron elastic scattering data off 40Ca, 90Zr, and 208Pb at energies E ≈5 -40 MeV, assuming a Perey and Buck [Nucl. Phys. 32, 353 (1962), 10.1016/0029-5582(62)90345-0] or Tian et al. [Int. J. Mod. Phys. E 24, 1550006 (2015), 10.1142/S0218301315500068] nonlocal form for the optical potential. We introduce energy and asymmetry dependencies in the imaginary part of the potential and refit the data to obtain a global parametrization. Independently of the starting point in the minimization procedure, an energy dependence in the imaginary depth is required for a good description of the data across the included energy range. We present two parametrizations, both of which represent an improvement over the original potentials for the fitted nuclei as well as for other nuclei not included in our fit. Our results show that, even when including the standard Gaussian nonlocality in optical potentials, a significant energy dependence is required to describe elastic-scattering data.

  14. Energy independent optical potentials: construction and limitations

    International Nuclear Information System (INIS)

    Hussein, M.S.; Moniz, E.J.

    1983-11-01

    Properties of the energy-independent potential U sup(-) which is wave-function-equivalent to the usual optical potential U(E) are constructed and examined. A simple procedure is presented for constructing U sup(-) in the uniform medium, and physical examples are discussed. The general result for finite systems, a recursive expansion in powers of U(E), is used to investigate the multiple scattering expansion of U sup(-); the energy-independent potential is found to have serious short-comings for direct microscopic construction or phenomenological parametrization. The microscopic theory, as exemplified here by the multiple scattering approach, does not lead to a reliable approximation scheme. Phenomenological approaches to U sup(-) are unattractive because the physics does not guide the parametrization effectively: the structure of the nonlocality is not tied directly to the dynamics; Im U sup(-) changes sign; different elements of the physics, separate in U(E), are completely entangled in U sup(-). (Author) [pt

  15. Theoretical study on optical model potential

    International Nuclear Information System (INIS)

    Lim Hung Gi.

    1984-08-01

    The optical model potential of non-local effect on the rounded edge of the potential is derived. On the basis of this potential the functional form of the optical model potential, the energy dependence and relationship of its parameters, and the dependency of the values of the parameters on energy change are shown in this paper. (author)

  16. Perspectives of optical lattices with state-dependent tunneling in approaching quantum magnetism in the presence of the external harmonic trapping potential

    International Nuclear Information System (INIS)

    Sotnikov, Andrii

    2016-01-01

    We study theoretically potential advantages of two-component mixtures in optical lattices with state-dependent tunneling for approaching long-range-order phases and detecting easy-axis antiferromagnetic correlations. While we do not find additional advantages of mixtures with large hopping imbalance for approaching quantum magnetism in a harmonic trap, it is shown that a nonzero difference in hopping amplitudes remains highly important for a proper symmetry breaking in the pseudospin space for the single-site-resolution imaging and can be advantageously used for a significant increase of the signal-to-noise ratio and thus detecting long-range easy-axis antiferromagnetic correlations in the corresponding experiments. - Highlights: • The most optimal ways to observe magnetic correlations in a quantum-gas microscope are presented. • Importance of a controlled symmetry breaking for antiferromagnetism is studied. • A quantitative theoretical analysis for the entropy in ultracold fermionic mixtures is performed. • No advantages from realizations with the strong hopping asymmetry are found.

  17. Dynamical equations for the optical potential

    International Nuclear Information System (INIS)

    Kowalski, K.L.

    1981-01-01

    Dynamical equations for the optical potential are obtained starting from a wide class of N-particle equations. This is done with arbitrary multiparticle interactions to allow adaptation to few-body models of nuclear reactions and including all effects of nucleon identity. Earlier forms of the optical potential equations are obtained as special cases. Particular emphasis is placed upon obtaining dynamical equations for the optical potential from the equations of Kouri, Levin, and Tobocman including all effects of particle identity

  18. Ab initio optical potentials applied to low-energy e-H2 and e-N2 collisions in the linear-algebraic approach

    International Nuclear Information System (INIS)

    Schneider, B.I.; Collins, L.A.

    1983-01-01

    We propose a method for constructing an effective optical potential through which correlation effects can be introduced into the electron-molecule scattering formulation. The optical potential is based on a nonperturbative, Feshbach projection-operator procedure and is evaluated on an L 2 basis. The optical potential is incorporated into the scattering equations by means of a separable expansion, and the resulting scattering equations are solved by a linear-algebraic method based on the integral-equation formulation. We report the results of scattering calculations, which include polarization effects, for low-energy e-H 2 and e-N 2 collisions. The agreement with other theoretical and with experimental results is quite good

  19. The radial shapes of intermediate energy microscopic optical potentials

    International Nuclear Information System (INIS)

    Shen Qingbiao; Wang Chang; Tian Ye; Zhuo Yizhong

    1984-01-01

    The radial shapes of intermediate energy proton microscopic optical potentials of 40 Ca are calculated with nuclear matter approach by Skyrme interactions. The calculated results show that the real central potential in central region of nucleus changes from attractive to repulsive when the energy of incident nucleon is above 150 MeV and appears apparently a 'wine-bottle-bottom' shape in the transition energy region (from 150 MeV to 300 MeV). This tendency is consistent with empirical optical potential obtained through fitting experiments and microscopic optical potential calculated with relativistic mean field theory as well as with the BHF theory. The calculated imaginary part of the microscopic optical potential changes from the dominant surface absorption into the volume absorption and its absolute value become larger as energy increases. The effects of Skyrme force parameters to the radial shape of the calculated microscopic optical potential are analysed in detail

  20. Perspective and potential of smart optical materials

    Science.gov (United States)

    Choi, Sang H.; Duzik, Adam J.; Kim, Hyun-Jung; Park, Yeonjoon; Kim, Jaehwan; Ko, Hyun-U.; Kim, Hyun-Chan; Yun, Sungryul; Kyung, Ki-Uk

    2017-09-01

    The increasing requirements of hyperspectral imaging optics, electro/photo-chromic materials, negative refractive index metamaterial optics, and miniaturized optical components from micro-scale to quantum-scale optics have all contributed to new features and advancements in optics technology. Development of multifunctional capable optics has pushed the boundaries of optics into new fields that require new disciplines and materials to maximize the potential benefits. The purpose of this study is to understand and show the fundamental materials and fabrication technology for field-controlled spectrally active optics (referred to as smart optics) that are essential for future industrial, scientific, military, and space applications, such as membrane optics, filters, windows for sensors and probes, telescopes, spectroscopes, cameras, light valves, light switches, and flat-panel displays. The proposed smart optics are based on the Stark and Zeeman effects in materials tailored with quantum dot arrays and thin films made from readily polarizable materials via ferroelectricity or ferromagnetism. Bound excitonic states of organic crystals are also capable of optical adaptability, tunability, and reconfigurability. To show the benefits of smart optics, this paper reviews spectral characteristics of smart optical materials and device technology. Experiments testing the quantum-confined Stark effect, arising from rare earth element doping effects in semiconductors, and applied electric field effects on spectral and refractive index are discussed. Other bulk and dopant materials were also discovered to have the same aspect of shifts in spectrum and refractive index. Other efforts focus on materials for creating field-controlled spectrally smart active optics on a selected spectral range. Surface plasmon polariton transmission of light through apertures is also discussed, along with potential applications. New breakthroughs in micro scale multiple zone plate optics as a micro

  1. Innovative approach towards understanding optics

    International Nuclear Information System (INIS)

    Garg, Amit; Bharadwaj, Sadashiv Raj; Kumar, Raj; Shudhanshu, Avinash Kumar; Verma, Deepak Kumar

    2016-01-01

    Over the last few years, there has been a decline in the students’ interest towards Science and Optics. Use of technology in the form of various types of sensors and data acquisition systems has come as a saviour. Till date, manual routine tools and techniques are used to perform various experimental procedures in most of the science/optics laboratories in our country. The manual tools are cumbersome whereas the automated ones are costly. It does not enthuse young researchers towards the science laboratories. There is a need to develop applications which can be easily integrated, tailored at school and undergraduate level laboratories and are economical at the same time. Equipments with advanced technologies are available but they are uneconomical and have complicated working principle with a black box approach. The present work describes development of portable tools and applications which are user-friendly. This is being implemented using open-source physical computing platform based on a simple low cost microcontroller board and a development environment for writing software. The present paper reports the development of an automated spectrometer, an instrument used in almost all optics experiments at undergraduate level, and students’ response to this innovation. These tools will inspire young researchers towards science and facilitate development of advance low cost equipments making life easier for Indian as well as developing nations. (paper)

  2. Nonresonant approximations to the optical potential

    International Nuclear Information System (INIS)

    Kowalski, K.L.

    1982-01-01

    A new class of approximations to the optical potential, which includes those of the multiple-scattering variety, is investigated. These approximations are constructed so that the optical potential maintains the correct unitarity properties along with a proper treatment of nucleon identity. The special case of nucleon-nucleus scattering with complete inclusion of Pauli effects is studied in detail. The treatment is such that the optical potential receives contributions only from subsystems embedded in their own physically correct antisymmetrized subspaces. It is found that a systematic development of even the lowest-order approximations requires the use of the off-shell extension due to Alt, Grassberger, and Sandhas along with a consistent set of dynamical equations for the optical potential. In nucleon-nucleus scattering a lowest-order optical potential is obtained as part of a systematic, exact, inclusive connectivity expansion which is expected to be useful at moderately high energies. This lowest-order potential consists of an energy-shifted (trho)-type term with three-body kinematics plus a heavy-particle exchange or pickup term. The natural appearance of the exchange term additivity in the optical potential clarifies the role of the elastic distortion in connection with the treatment of these processes. The relationship of the relevant aspects of the present analysis of the optical potential to conventional multiple scattering methods is discussed

  3. The dependence on energy and mass-number of the α-particle optical potential: A justification for the folding model approach

    International Nuclear Information System (INIS)

    Friedman, E.; Gils, H.J.; Rebel, H.; Pesl, R.

    1980-09-01

    Data for elastic scattering of α-particles by sup(40,42,44,48)Ca, 50 Ti, 52 Cr and 90 Zr at 104 MeV, by 40 Ca, sup(46,48,50)Ti, 58 Ni, 90 Zr and 208 Pb at 140 MeV and by sup(58,60,62,64)Ni at 173 MeV are analysed using a Fourier-Bessel description of the optical potential. All data extend to large angles thus allowing unique determination of volume integrals and rms radii of the potentials. The variations with mass number and energy of these quantities are investigated and conclusions are drawn about studies of nuclear radii with the help of optical potentials. (orig.)

  4. Molecular Approaches to Optical Biosensors

    National Research Council Canada - National Science Library

    Fierke, Carol

    1998-01-01

    The goal of this proposal was to develop methodologies for the optimization of field-deployable optical biosensors, in general, and, in particular, to optimize a carbonic anhydrase-based fiber optic zinc biosensor...

  5. Skin optical clearing potential of disaccharides

    Science.gov (United States)

    Feng, Wei; Shi, Rui; Ma, Ning; Tuchina, Daria K.; Tuchin, Valery V.; Zhu, Dan

    2016-08-01

    Skin optical clearing can significantly enhance the ability of biomedical optical imaging. Some alcohols and sugars have been selected to be optical clearing agents (OCAs). In this work, we paid attention to the optical clearing potential of disaccharides. Sucrose and maltose were chosen as typical disaccharides to compare with fructose, an excellent monosaccharide-OCA, by using molecular dynamics simulation and an ex vivo experiment. The experimental results indicated that the optical clearing efficacy of skin increases linearly with the concentration for each OCA. Both the theoretical predication and experimental results revealed that the two disaccharides exerted a better optical clearing potential than fructose at the same concentration, and sucrose is optimal. Since maltose has an extremely low saturation concentration, the other two OCAs with saturation concentrations were treated topically on rat skin in vivo, and optical coherence tomography imaging was applied to monitor the optical clearing process. The results demonstrated that sucrose could cause a more significant increase in imaging depth and signal intensity than fructose.

  6. Microscopic optical potential at medium energies

    International Nuclear Information System (INIS)

    Malecki, A.

    1979-01-01

    The problems concerning a microscopic optical model for the elastic nuclear collisions at medium energies are discussed. We describe the method for constructing the optical potential which makes use of the particular properties of quantum scattering in the eikonal limit. The resulting potential is expressed in terms of the nuclear wave functions and the nucleon-nucleon scattering amplitudes. This potential has a dynamic character since by including the effects of multiple scattering it allows for the possibility of intermediate excitations of the projectile and target nuclei. The use of the potential in the exact wave equation accounts for the most important mechanisms present in the collisions between composite particles. The microscopic optical model was successfully applied in the analysis of elastic scattering of protons and α-particles on atomic nuclei in the energy range of 300-1000 MeV/nucleon. The dynamic optical potential in this case represents a considerable improvement over the eikonal Glauber model and the static optical potential of Watson. The possibilities to extend the microscopic description of the proton-nucleus interaction by considering the spin dependence of the elementary amplitude and the Majorana exchange effects were investigated. (author)

  7. Neutron relativistic phenomenological and microscopic optical potential

    International Nuclear Information System (INIS)

    Shen Qing-biao; Feng Da-chun; Zhuo Yi-zhong

    1991-01-01

    In this paper, both the phenomenological and microscopic neutron relativistic optical potentials are presented. The global neutron relativistic phenomenological optical potential (RPOP) based on the available experimental data for various nuclei ranging from C to U with incident energies E n =20--1000 MeV has been obtained through an automatic search of the best parameters by computer. Then the nucleon relativistic microscopic optical potential (RMOP) is studied by utilizing the effective Lagrangian based on the popular Walecka model. Through comparison between the theoretical results and experimental data we shed some insight into both the RMOP and RPOP. Further improvement concerning how to combine the phenomenological potential with the microscopic one in order to reduce the number of free parameters appearing in the RPOP is suggested

  8. Nonlinear optics an analytical approach

    CERN Document Server

    Mandel, Paul

    2010-01-01

    Based on the author's extensive teaching experience and lecture notes, this textbook provides a substantially analytical rather than descriptive presentation of nonlinear optics. Divided into five parts, with most chapters corresponding to a two-hour lecture, the book begins with a unique account of the historical development from Kirchhoff's law for the black-body radiation to Planck's quantum hypothesis and Einstein's discovery of spontaneous emission - providing all the explicit proofs. The subsequent sections deal with matter quantization, ultrashort pulse propagation in 2-level media, cavity nonlinear optics, chi(2) and chi(3) media. For graduate and PhD students in nonlinear optics or photonics, while also representing a valuable reference for researchers in these fields.

  9. A novel approach to dual excitation ratiometric optical mapping of cardiac action potentials with di-4-ANEPPS using pulsed LED excitation.

    Science.gov (United States)

    Bachtel, Andrew D; Gray, Richard A; Stohlman, Jayna M; Bourgeois, Elliot B; Pollard, Andrew E; Rogers, Jack M

    2011-07-01

    We developed a new method for ratiometric optical mapping of transmembrane potential (V(m)) in cardiac preparations stained with di-4-ANEPPS. V(m)-dependent shifts of excitation and emission spectra establish two excitation bands (481 nm) that produce fluorescence changes of opposite polarity within a single emission band (575-620 nm). The ratio of these positive and negative fluorescence signals (excitation ratiometry) increases V(m) sensitivity and removes artifacts common to both signals. We pulsed blue (450 ± 10 nm) and cyan (505 ± 15 nm) light emitting diodes (LEDs) at 375 Hz in alternating phase synchronized to a camera (750 frames-per-second). Fluorescence was bandpass filtered (585 ± 20 nm). This produced signals with upright (blue) and inverted (cyan) action potentials (APs) interleaved in sequential frames. In four whole swine hearts with motion chemically arrested, fractional fluorescence for blue, cyan, and ratio signals was 1.2 ± 0.3%, 1.2 ± 0.3%, and 2.4 ± 0.6%, respectively. Signal-to-noise ratios were 4.3 ± 1.4, 4.0 ± 1.2, and 5.8 ± 1.9, respectively. After washing out the electromechanical uncoupling agent, we characterized motion artifact by cross-correlating blue, cyan, and ratio signals with a signal with normal AP morphology. Ratiometry improved cross-correlation coefficients from 0.50 ± 0.48 to 0.81 ± 0.25, but did not cancel all motion artifacts. These findings demonstrate the feasibility of pulsed LED excitation ratiometry in myocardium. © 2011 IEEE

  10. RPA correction to the optical potential

    Directory of Open Access Journals (Sweden)

    Bauge E.

    2010-03-01

    Full Text Available In studies of nucleon elastic scattering, a correction to the microscopic optical potential built from Melbourne g-matrix was found to be necessary at low nucleon incident energy [1,2]. Indeed, at energies lower than 60 MeV, the absorption generated from Melbourne g-matrix is too weak within 25%. Coupling to collective excited states of the target nucleus are not included in the g-matrix and could explain the missing absorption. We propose to calculate this correction to the optical potential using the Gogny D1S effective nucleon-nucleon interaction in the coupling to excited states of the target. We use the Random Phase Approximation (RPA description of the excited states of the target with the same interaction.

  11. Covariant single-hole optical potential

    International Nuclear Information System (INIS)

    Kam, J. de

    1982-01-01

    In this investigation a covariant optical potential model is constructed for scattering processes of mesons from nuclei in which the meson interacts repeatedly with one of the target nucleons. The nuclear binding interactions in the intermediate scattering state are consistently taken into account. In particular for pions and K - projectiles this is important in view of the strong energy dependence of the elementary projectile-nucleon amplitude. Furthermore, this optical potential satisfies unitarity and relativistic covariance. The starting point in our discussion is the three-body model for the optical potential. To obtain a practical covariant theory I formulate the three-body model as a relativistic quasi two-body problem. Expressions for the transition interactions and propagators in the quasi two-body equations are found by imposing the correct s-channel unitarity relations and by using dispersion integrals. This is done in such a way that the correct non-relativistic limit is obtained, avoiding clustering problems. Corrections to the quasi two-body treatment from the Pauli principle and the required ground-state exclusion are taken into account. The covariant equations that we arrive at are amenable to practical calculations. (orig.)

  12. Nanothermodynamics: a subdivision potential approach

    Directory of Open Access Journals (Sweden)

    R. Moussavi

    2005-12-01

    Full Text Available  Classical thermodynamic laws and relations have been developed for macroscopic systems that satisfy the thermodynamic limit. These relations are challenged as the system size decreases to the scale of nano-systems, in which thermodynamic properties are overshadowed by system size, and the usual classical concepts of extensivity and intensivity are no longer valid. The challenges to the classical thermodynamics in relation to small systems are demonstrated, and via the approach introduced by Hill, the concept of sub-division potential is clarified in details. The fundamental thermodynamic relations are obtained using a rational-based method.

  13. Multifocal visual evoked potential in optic neuritis, ischemic optic neuropathy and compressive optic neuropathy

    Science.gov (United States)

    Jayaraman, Manju; Gandhi, Rashmin Anilkumar; Ravi, Priya; Sen, Parveen

    2014-01-01

    Purpose: To investigate the effect of optic neuritis (ON), ischemic optic neuropathy (ION) and compressive optic neuropathy (CON) on multifocal visual evoked potential (mfVEP) amplitudes and latencies, and to compare the parameters among three optic nerve disorders. Materials and Methods: mfVEP was recorded for 71 eyes of controls and 48 eyes of optic nerve disorders with subgroups of optic neuritis (ON, n = 21 eyes), ischemic optic neuropathy (ION, n = 14 eyes), and compressive optic neuropathy (CON, n = 13 eyes). The size of defect in mfVEP amplitude probability plots and relative latency plots were analyzed. The pattern of the defect in amplitude probability plot was classified according to the visual field profile of optic neuritis treatment trail (ONTT). Results: Median of mfVEP amplitude (log SNR) averaged across 60 sectors were reduced in ON (0.17 (0.13-0.33)), ION (0.14 (0.12-0.21)) and CON (0.21 (0.14-0.30)) when compared to controls. The median mfVEP relative latencies compared to controls were significantly prolonged in ON and CON group of 10.53 (2.62-15.50) ms and 5.73 (2.67-14.14) ms respectively compared to ION group (2.06 (-4.09-13.02)). The common mfVEP amplitude defects observed in probability plots were diffuse pattern in ON, inferior altitudinal defect in ION and temporal hemianopia in CON eyes. Conclusions: Optic nerve disorders cause reduction in mfVEP amplitudes. The extent of delayed latency noted in ischemic optic neuropathy was significantly lesser compared to subjects with optic neuritis and compressive optic neuropathy. mfVEP amplitudes can be used to objectively assess the topography of the visual field defect. PMID:24088641

  14. Probing molecular potentials with an optical centrifuge

    Science.gov (United States)

    Milner, A. A.; Korobenko, A.; Hepburn, J. W.; Milner, V.

    2017-09-01

    We use an optical centrifuge to excite coherent rotational wave packets in N2O, OCS, and CS2 molecules with rotational quantum numbers reaching up to J ≈465 , 690, and 1186, respectively. Time-resolved rotational spectroscopy at such ultra-high levels of rotational excitation can be used as a sensitive tool to probe the molecular potential energy surface at internuclear distances far from their equilibrium values. Significant bond stretching in the centrifuged molecules results in the growing period of the rotational revivals, which are experimentally detected using coherent Raman scattering. We measure the revival period as a function of the centrifuge-induced rotational frequency and compare it with the numerical calculations based on the known Morse-cosine potentials.

  15. Bragg diffraction of fermions at optical potentials

    International Nuclear Information System (INIS)

    Deh, Benjamin

    2008-01-01

    This thesis describes the Bragg diffraction of ultracold fermions at an optical potential. A moving optical lattice was created, by overlaying two slightly detuned lasers. Atoms can be diffracted at this lattice if the detuning fulfills the Bragg condition for resting atoms. This Bragg diffraction is analyzed systematically in this thesis. To this end Rabi oscillations between the diffraction states were driven, as well in the weakly interacting Bragg regime, as in the strongly interacting Kapitza-Dirac regime. Simulations, based on a driven two-, respectively multilevel-system describe the observed effects rather well. Furthermore, the temporal evolution of the diffracted states in the magnetic trapping potential was studied. The anharmonicity of the trap in use and the scattering cross section for p-wave collisions in a 6 Li system was determined from the movement of these states. Moreover the momentum distribution of the fermions was measured with Bragg spectroscopy and first signs of Fermi degeneracy were found. Finally an interferometer with fermions was build, exhibiting a coherence time of more than 100 μs. With this, the possibility for measurement and manipulation of ultracold fermions with Bragg diffraction could bee shown. (orig.)

  16. Phenomenological dirac optical potential for neutron cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Shin-ichi; Kitsuki, Hirohiko; Shigyo, Nobuhiro; Ishibashi, Kenji [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering

    1997-03-01

    Because of limitation on neutron-incident data, it is difficult to obtain global optical model potential for neutrons. In contrast, there are some global optical model potentials for proton in detail. It is interesting to convert the proton-incident global optical potentials into neutron-incident ones. In this study we introduce (N-Z)/A dependent symmetry potential terms into the global proton-incident optical potentials, and then obtain neutron-incident ones. The neutron potentials reproduce total cross sections in an acceptable degree. However, a comparison with potentials proposed by other authors brings about a confused situation in the sign of the symmetry terms. (author)

  17. Phenomenological optical potentials and optical model computer codes

    International Nuclear Information System (INIS)

    Prince, A.

    1980-01-01

    An introduction to the Optical Model is presented. Starting with the purpose and nature of the physical problems to be analyzed, a general formulation and the various phenomenological methods of solution are discussed. This includes the calculation of observables based on assumed potentials such as local and non-local and their forms, e.g. Woods-Saxon, folded model etc. Also discussed are the various calculational methods and model codes employed to describe nuclear reactions in the spherical and deformed regions (e.g. coupled-channel analysis). An examination of the numerical solutions and minimization techniques associated with the various codes, is briefly touched upon. Several computer programs are described for carrying out the calculations. The preparation of input, (formats and options), determination of model parameters and analysis of output are described. The class is given a series of problems to carry out using the available computer. Interpretation and evaluation of the samples includes the effect of varying parameters, and comparison of calculations with the experimental data. Also included is an intercomparison of the results from the various model codes, along with their advantages and limitations. (author)

  18. Fiber Optic Detection of Action Potentials in Axons

    National Research Council Canada - National Science Library

    Smela, Elisabeth

    2006-01-01

    In prior exploratory research, we had designed a fiber optic sensor utilizing a long period Bragg grating for the purpose of detecting action potentials in axons optically, through a change in index...

  19. Fourier synthesis of asymmetrical optical potentials for atoms

    International Nuclear Information System (INIS)

    Ritt, G.

    2007-01-01

    In this work a dissipationless asymmetrical optical potential for cold atoms was produced. In a first step a new type of optical lattice was generated, whose spatial periodicity only corresponds to a quarter of the wavelength of the light used for the generation. This corresponds to the half of the periodicity of a conventional optical lattice, which is formed by the light of the same wavelength. The generation of this new type of optical lattice was reached by the use of two degenerated raman transitions. Virtual processes occur, in which four photons are involved. In conventional optical lattices however virtual two-photon processes occur. By spatially superimposing this optical lattice with a conventional optical lattice an asymmetrical optical potential could be formed. By diffraction of a Bose Einstein condensate of rubidium atoms at the transient activated asymmetrical potential the asymmetrical structure was proven. (orig.)

  20. Beam splitter phase shifts: Wave optics approach

    Science.gov (United States)

    Agnesi, Antonio; Degiorgio, Vittorio

    2017-10-01

    We investigate the phase relationships between transmitted and reflected waves in a lossless beam splitter having a multilayer structure, using the matrix approach as outlined in classical optics books. Contrarily to the case of the quantum optics formalism generally employed to describe beam splitters, these matrices are not unitary. In this note we point out the existence of general relations among the elements of the transfer matrix that describes the multilayer beam splitter. Such relations, which are independent of the detailed structure of the beam splitter, fix the phase shifts between reflected and transmitted waves. It is instructive to see how the results obtained by Zeilinger by using spinor algebra and Pauli matrices can be easily derived from our general relations.

  1. Structure of the real part of the nucleon optical potential

    International Nuclear Information System (INIS)

    Kadmensky, S.G.; Lyuboshitz, V.V.; Shaikina, A.A.

    1995-01-01

    The components of the nucleon optical potential V(l, E) in the 208 Pb and 40 Ca nuclei are calculated on the basis of the generalized Hartree-Fock potential and using typical sets of vacuum NN forces. The parameters of the isoscalar component of V(1, E) are found to agree well with those of phenomenological optical potentials and of the optical potentials in the Skyrme model. The isovector component of V(1, E) strongly depends on energy, and its value at E = 0 is considerably less than the corresponding values of the phenomenological and Skyrme optical potentials. This points to the necessity of additional tests of the underlying pair NN potentials. The radial distribution of V(1, E) is more complicated than the radial dependence of phenomenological optical potentials. 6 refs., 5 figs

  2. Analysis of the normal optical, Michel and molecular potentials on ...

    Indian Academy of Sciences (India)

    6. — journal of. June 2016 physics pp. 1275–1286. Analysis of the normal ... the levels are obtained for the three optical potentials to estimate the quality ... The experimental angular distribution data for the 40Ca(6Li, d)44Ti reaction .... analysed using the normal optical, Michel and molecular potentials within the framework.

  3. Study on the nonlocality effects for generalized optical potentials

    International Nuclear Information System (INIS)

    Gurbanovich, I.S.; Zelenskaya, N.S.

    1981-01-01

    In previous studies the authors have ihown that the generalized optic potential (GOP) of particles interaction is a superposition of local and non local potentials (LP, NLP). On the example of α- particles scattering on the 8 Be nucleus at about 10-15 MeV the GOP nonlocal part is considered. For obtaining NLP the spectral decomposition of the Green function taking into account only contribution of relative motion of two α-particles in S-state is used. The locally-equivalent addition to central potential of α-particles scattering at 8 Be previously calculated is obtained. In a graphical form a total locally-equivalent potential and local GOP part are presented. It is shown that taking into account the nonlocallity effect in a locally energy approximation for precise wave function in S-state widen a potential hole without changing its depth. Such widening corresponds to the general character of behaviour of non local potentials calculated in the microscopic approach [ru

  4. Square well approximation to the optical potential

    International Nuclear Information System (INIS)

    Jain, A.K.; Gupta, M.C.; Marwadi, P.R.

    1976-01-01

    Approximations for obtaining T-matrix elements for a sum of several potentials in terms of T-matrices for individual potentials are studied. Based on model calculations for S-wave for a sum of two separable non-local potentials of Yukawa type form factors and a sum of two delta function potentials, it is shown that the T-matrix for a sum of several potentials can be approximated satisfactorily over all the energy regions by the sum of T-matrices for individual potentials. Based on this, an approximate method for finding T-matrix for any local potential by approximating it by a sum of suitable number of square wells is presented. This provides an interesting way to calculate the T-matrix for any arbitary potential in terms of Bessel functions to a good degree of accuracy. The method is applied to the Saxon-Wood potentials and good agreement with exact results is found. (author)

  5. An approach to the optical MSD adder

    Science.gov (United States)

    Takahashi, Hideya; Matsushita, Kenji; Shimizu, Eiji

    1990-07-01

    The intrinsic parallelism of optical elements for computation is presently taken fuller advantage of than heretofore possible through an optical implementation of the modified signed digit (MSD) number system, which yields carry-free addition and subtraction. In the present optical implementation of the MSD system, optical phase data are used to preclude negative value representation. Attention is given to an MSD adder array for addition operations on two n-digit trinary numbers; the output is composed of n + 1 trinary digits.

  6. Trapping of a microsphere pendulum resonator in an optical potential

    International Nuclear Information System (INIS)

    Ward, J. M.; Wu, Y.; Nic Chormaic, S.; Minogin, V. G.

    2009-01-01

    We propose a method to spatially confine or corral the movements of a micropendulum via the optical forces produced by two simultaneously excited optical modes of a photonic molecule comprising two microspherical cavities. We discuss how the cavity-enhanced optical force generated in the photonic molecule can create an optomechanical potential of about 10 eV deep and 30 pm wide, which can be used to trap the pendulum at any given equilibrium position by a simple choice of laser frequencies. This result presents opportunities for very precise all-optical self-alignment of microsystems.

  7. The unification of the nuclear optical potential

    International Nuclear Information System (INIS)

    Hodgson, P.E.

    1990-01-01

    The nuclear mean field is defined for bound and scattering states and its parameters shown to vary continuously over the whole energy range. The real and imaginary parts of the potential are connected by dispersion relations, and this unifies the potential from negative to positive energies. Recent analyses of experimental data using dispersion relations are reviewed. (author)

  8. Application of Tietz potential to study optical properties of spherical ...

    Indian Academy of Sciences (India)

    c Indian Academy of Sciences. Vol. 85, No. 4. — journal of. October 2015 ... The physical properties of semiconductors such as optical, electronic, and thermodynamic .... can be used to reproduce the interaction potential energy curve of the A1.

  9. One-nucleon transfer reactions and the optical potential

    CERN Document Server

    Nunes, F M; Ross, A; Titus, L J; Charity, R J; Dickhoff, W H; Mahzoon, M H; Sarich, J; Wild, S M

    2015-01-01

    We provide a summary of new developments in the area of direct reaction theory with a particular focus on one-nucleon transfer reactions. We provide a status of the methods available for describing (d,p) reactions. We discuss the effects of nonlocality in the optical potential in transfer reactions. The results of a purely phenomenological potential and the optical potential obtained from the dispersive optical model are compared; both point toward the importance of including nonlocality in transfer reactions explicitly. Given the large ambiguities associated with optical potentials, we discuss some new developments toward the quantification of this uncertainty. We conclude with some general comments and a brief account of new advances that are in the pipeline.

  10. Unitarity constraints in the construction of optical potentials

    International Nuclear Information System (INIS)

    Cannata, F.; Deponder, J.P.; Lenz, F.

    1982-01-01

    We first review the unitarity properties of the first order optical potential theory which arise from the one-body nature of both the single scattering approximation and of the single particle model for the nucleus. We construct optical potentials relaxing either the independent particle guided by the requirement of incorporating the minimal unitary of the first order theory and extending it to more complex situations. Our investigation of the effects of nucleon-nucleon residual interaction results in a description of the quasifree mechanism modified by final state unitarity requires the inclusion of all possible scattering processes on a given pair of target nucleons. This naturally leads to a formation of the optical potential in terms of three-body rather than two-body amplitudes. We discuss various approximation which make, in combination with phenomenological ingredients, an evaluation of these optical potentials feasible

  11. Quantum degenerate atomic gases in controlled optical lattice potentials

    Science.gov (United States)

    Gemelke, Nathan D.

    2007-12-01

    Since the achievement of Bose Einstein condensation in cold atomic gases, mean-field treatments of the condensed phase have provided an excellent description for the static and dynamic properties observed in experiments. Recent experimental efforts have focused on studying deviations from mean-field behavior. I will describe work on two experiments which introduce controlled single particle degeneracies with time-dependent optical potentials, aiming to induce correlated motion and nontrivial statistics in the gas. In the first experiment, an optical lattice with locally rotating site potentials is produced to investigate fractional quantum Hall effects (FQHE) in rotating Bose gases. Here, the necessary gauge potential is provided by the rotating reference frame of the gas, which, in direct analogy to the electronic system, organizes single particle states into degenerate Landau levels. At low temperatures the repulsive interaction provided by elastic scattering is expected to produce ground states with structure nearly identical to those in the FQHE. I will discuss how these effects are made experimentally feasible by working at small particle numbers in the tight trapping potentials of an optical lattice, and present first results on the use of photoassociation to probe correlation in this system. In the second experiment, a vibrated optical lattice potential alters the single-particle dispersion underlying a condensed Bose gas and offers tailored phase-matching for nonlinear atom optical processes. I will demonstrate how this leads to parametric instability in the condensed gas, and draw analogy to an optical parametric oscillator operating above threshold.

  12. A semiclassical study of optical potentials - potential resonances -

    International Nuclear Information System (INIS)

    Lee, S.Y.; Takigawa, N.; Marty, C.

    1977-01-01

    A semiclassical method is used to analyze resonances produced by complex potentials. The absorption plays a central role: when it is not too great, resonances manifest themselves by enhancement of cross sections near π. The reverse is not necessarily true, for instance the anomalous large angle scattering for α-Ca is due to a coherent superposition of many partial waves

  13. Dynamics of Bose-Einstein condensates in novel optical potentials

    Energy Technology Data Exchange (ETDEWEB)

    Kueber, Johannes

    2014-07-21

    Matter wave interferometry offers a novel approach for high precision measurements, such as the determination of physical constants like the local gravity constant g or the fine-structure constant. Since its early demonstration, it has become an important tool in the fields of fundamental and applied physics. The present work covers the implementation of matter wave interferometers as well as the creation of novel guiding potentials for ultra-cold ensembles of atoms and Bose-Einstein condensates for this purpose. In addition, novel techniques for the manipulation of atoms with Bragg lattices are presented, serving as elements for interferometry. The measurements in this work are performed with a Bose-Einstein condensate of 25000 {sup 87}rubidium atoms created in a crossed optical dipole trap. The crossed optical dipole trap is loaded from a magneto-optical trap and allows a measurement every 25 s. This work introduces the novel technique of double Bragg diffraction as a tool for atom optics for the first time experimentally. The creation of beamsplitters and mirrors for advanced interferometric measurements is characterized. An in depth discussion on the momentum distribution of atomic clouds and its influence on double Bragg diffraction is given. Additionally experimental results for higher-order Bragg diffraction are explained and double Bragg diffraction is used to implement a full Ramsey-type interferometer. A second central result of this work is the implementation of novel guiding structures for ultra-cold atoms. These structures are created with conical refraction, an effect that occurs when light is guided along one of the optical axis of a bi-axial crystal. The conical refraction crystal used to operate the novel trapping geometries is a KGd(WO{sub 4}){sub 2} crystal that has been specifically cut orthogonal to one of the optical axis. Two regimes are discussed in detail: the creation of a toroidal matter wave guide and the implementation of a three

  14. Optical Remote Sensing Potentials for Looting Detection

    Directory of Open Access Journals (Sweden)

    Athos Agapiou

    2017-10-01

    Full Text Available Looting of archaeological sites is illegal and considered a major anthropogenic threat for cultural heritage, entailing undesirable and irreversible damage at several levels, such as landscape disturbance, heritage destruction, and adverse social impact. In recent years, the employment of remote sensing technologies using ground-based and/or space-based sensors has assisted in dealing with this issue. Novel remote sensing techniques have tackled heritage destruction occurring in war-conflicted areas, as well as illicit archeological activity in vast areas of archaeological interest with limited surveillance. The damage performed by illegal activities, as well as the scarcity of reliable information are some of the major concerns that local stakeholders are facing today. This study discusses the potential use of remote sensing technologies based on the results obtained for the archaeological landscape of Ayios Mnason in Politiko village, located in Nicosia district, Cyprus. In this area, more than ten looted tombs have been recorded in the last decade, indicating small-scale, but still systematic, looting. The image analysis, including vegetation indices, fusion, automatic extraction after object-oriented classification, etc., was based on high-resolution WorldView-2 multispectral satellite imagery and RGB high-resolution aerial orthorectified images. Google Earth© images were also used to map and diachronically observe the site. The current research also discusses the potential for wider application of the presented methodology, acting as an early warning system, in an effort to establish a systematic monitoring tool for archaeological areas in Cyprus facing similar threats.

  15. Optical mapping of optogenetically shaped cardiac action potentials

    Science.gov (United States)

    Park, Sarah A.; Lee, Shin-Rong; Tung, Leslie; Yue, David T.

    2014-01-01

    Light-mediated silencing and stimulation of cardiac excitability, an important complement to electrical stimulation, promises important discoveries and therapies. To date, cardiac optogenetics has been studied with patch-clamp, multielectrode arrays, video microscopy, and an all-optical system measuring calcium transients. The future lies in achieving simultaneous optical acquisition of excitability signals and optogenetic control, both with high spatio-temporal resolution. Here, we make progress by combining optical mapping of action potentials with concurrent activation of channelrhodopsin-2 (ChR2) or halorhodopsin (eNpHR3.0), via an all-optical system applied to monolayers of neonatal rat ventricular myocytes (NRVM). Additionally, we explore the capability of ChR2 and eNpHR3.0 to shape action-potential waveforms, potentially aiding the study of short/long QT syndromes that result from abnormal changes in action potential duration (APD). These results show the promise of an all-optical system to acquire action potentials with precise temporal optogenetics control, achieving a long-sought flexibility beyond the means of conventional electrical stimulation. PMID:25135113

  16. The imaginary part of the nucleus - nucleus optical potential

    International Nuclear Information System (INIS)

    Phatak, S.C.; Sinha, B.

    1978-01-01

    The contribution to the imaginary nucleus - nucleus optical potential has been estimated by evaluating the energy - conserving seocond-order term in the perturbation series. The incoming nuclear field is supposed to excite nucleons in a nucleus in this calculation and the nuclear excitations are approximated by particle-hole excitations in a Fermi gas. The resulting imaginary potential compares favourably with phenomenological potentials. (author)

  17. Optical-potential model for electron-atom scattering

    International Nuclear Information System (INIS)

    Callaway, J.; Oza, D.H.

    1985-01-01

    It is proposed that the addition of a matrix optical potential to a close-coupling calculation should lead to improved results in studies of electron-atom scattering. This procedure is described with use of a pseudostate expansion to evaluate the optical potential. The integro-differential equations are solved by a linear-algebraic method. As a test case, applications are made to electron-hydrogen scattering, and the results are compared with those obtained by other calculational procedures, and with experiment

  18. Potential of OFDM for next generation optical access

    Science.gov (United States)

    Fritzsche, Daniel; Weis, Erik; Breuer, Dirk

    2011-01-01

    This paper shows the requirements for next generation optical access (NGOA) networks and analyzes the potential of OFDM (orthogonal frequency division multiplexing) for the use in such network scenarios. First, we show the motivation for NGOA systems based on the future requirements on FTTH access systems and list the advantages of OFDM in such scenarios. In the next part, the basics of OFDM and different methods to generate and detect optical OFDM signals are explained and analyzed. At the transmitter side the options include intensity modulation and the more advanced field modulation of the optical OFDM signal. At the receiver there is the choice between direct detection and coherent detection. As the result of this discussion we show our vision of the future use of OFDM in optical access networks.

  19. State-dependent fluorescence of neutral atoms in optical potentials

    Science.gov (United States)

    Martinez-Dorantes, M.; Alt, W.; Gallego, J.; Ghosh, S.; Ratschbacher, L.; Meschede, D.

    2018-02-01

    Recently we have demonstrated scalable, nondestructive, and high-fidelity detection of the internal state of 87Rb neutral atoms in optical dipole traps using state-dependent fluorescence imaging [M. Martinez-Dorantes, W. Alt, J. Gallego, S. Ghosh, L. Ratschbacher, Y. Völzke, and D. Meschede, Phys. Rev. Lett. 119, 180503 (2017), 10.1103/PhysRevLett.119.180503]. In this paper we provide experimental procedures and interpretations to overcome the detrimental effects of heating-induced trap losses and state leakage. We present models for the dynamics of optically trapped atoms during state-dependent fluorescence imaging and verify our results by comparing Monte Carlo simulations with experimental data. Our systematic study of dipole force fluctuations heating in optical traps during near-resonant illumination shows that off-resonant light is preferable for state detection in tightly confining optical potentials.

  20. Spectral approach to optical resonator theory

    International Nuclear Information System (INIS)

    Feit, M.D.; Fleck, J.A. Jr.

    1981-01-01

    A new computational method for unloaded optical resonators is developed based on the discrete Fourier analysis of informaton generated by repated iterations of the optical field corresponding to transits between reflectors. The method is a straightforward extension of the propagating beam method developed earlier for optical fibers for extracting modal properties from numerical solutions to the paraxial scalar wave equation. The method requires computation of a field correlation function, whose Fourier transform reveals the eigenmodes as resonant peaks. Analysis of the location and breadth of these peaks determines the resonator eigenvalues When the eigenvalues are known, additional discrete Fourier transforms of the field are used to generate the mode eigenfunctions. This new method makes possible the unambiguous identification and accurate characterization of the entire spectrum of transverse resonator modes

  1. Heavy-ion optical potential for sub-barrier fusion deduced from a dispersion relation

    International Nuclear Information System (INIS)

    Kim, B.T.; Kim, H.C.; Park, K.E.

    1988-01-01

    The heavy-ion energy-dependent optical potentials for the 16 O+ 208 Pb system are deduced from a dispersion relation. These potentials are used to analyze the elastic scattering, fusion, and spin distributions of compound nuclei for the system in a unified way based on the direct reaction theory. It turns out that the energy dependence of the optical potential is essential in explaining the data at near- and sub-barrier energies. The real part of the energy-dependent optical potential deduced was also used in calculating the elastic and fusion cross sections by the conventional barrier penetration model using an incoming wave boundary condition. The predictions of the elastic scattering, fusion cross sections, and the spin distributions of compound nuclei are not satisfactory compared with those from the direct reaction approach. It seems to originate from the fact that this model neglects absorption around the Coulomb barrier region

  2. Optical potential study of electron scattering by rubidium

    Energy Technology Data Exchange (ETDEWEB)

    Chin, J. H.; Ratnavelu, K. [University of Malaya, Kuala Lumpur (Malaysia); Zhou, Y. [Harbin Institute of Technology, Harbin (China)

    2011-10-15

    The coupled-channel optical method (CCOM) has been implemented in a study of electronrubidium scattering. This method includes the continuum effect in the calculation via an ab-initio optical potential. Eight atomic states (5s, 5p, 4d, 6s, 6p, 5d, 7s, 7p) were used together with the continuum optical potential in the 5s-5s, 5s-5p, and 5p-5p coupling. The elastic, inelastic and total cross sections for electron-rubidium scattering at low and intermediate energies, ranging from 10 eV to 100 eV, are reported. The results are compared with available experimental and theoretical data.

  3. The optical potential for thermal neutrons in second approximation

    International Nuclear Information System (INIS)

    Nowak, E.

    1980-01-01

    After the construction of an expansion of the transfer operator for neutron scattering in terms of the scattering length the optical potential for coherent scattering is derived whereby the corrections due to the dynamic properties of the scattering system are discussed. (HSI) [de

  4. The Watanabe model for 6Li-nucleus optical potential

    International Nuclear Information System (INIS)

    Abul-Magd, A.Y.; Rabie, A.; El-Gazzar, M.A.

    1980-09-01

    Optical potentials for the scattering of 6 Li projectiles are calculated using the Watanabe model and an α+d cluster model wave function for 6 Li. Reasonable fits to the elastic differential cross-section and vector polarization are obtained. (author)

  5. Fast neutron capture and the microscopic isovector optical potential

    International Nuclear Information System (INIS)

    Chakrabarty, D.R.; Gupta, S.K.

    Neutron capture cross-sections are calculated with the direct-semidirect model employing the complex microscopic optical potential recently calculated by Jeukenne, Lejoune and Mahaux. The data for 89 Y, Ce and 208 Pb for Esub(n)=6-16 MeV agree well with the calculation for a twofold increase in the magnitude of the isovector part of the microscopic potential. (auth.)

  6. Coherent transport of matter waves in disordered optical potentials

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Robert

    2007-07-01

    The development of modern techniques for the cooling and the manipulation of atoms in recent years, and the possibility to create Bose-Einstein condensates and degenerate Fermi gases and to load them into regular optical lattices or disordered optical potentials, has evoked new interest for the disorder-induced localization of ultra-cold atoms. This work studies the transport properties of matter waves in disordered optical potentials, which are also known as speckle potentials. The effect of correlated disorder on localization is first studied numerically in the framework of the Anderson model. The relevant transport parameters in the configuration average over many different realizations of the speckle potential are then determined analytically, using self-consistent diagrammatic perturbation techniques. This allows to make predictions for a possible experimental observation of coherent transport phenomena for cold atoms in speckle potentials. Of particular importance are the spatial correlations of the speckle fluctuations, which are responsible for the anisotropic character of the single scattering processes in the effective medium. Coherent multiple scattering leads to quantum interference effects, which entail a renormalization of the diffusion constant as compared to the classical description. This so-called weak localization of matter waves is studied as the underlying mechanism for the disorder-driven transition to the Anderson-localization regime, explicitly taking into account the correlations of the speckle fluctuations. (orig.)

  7. Coherent transport of matter waves in disordered optical potentials

    International Nuclear Information System (INIS)

    Kuhn, Robert

    2007-01-01

    The development of modern techniques for the cooling and the manipulation of atoms in recent years, and the possibility to create Bose-Einstein condensates and degenerate Fermi gases and to load them into regular optical lattices or disordered optical potentials, has evoked new interest for the disorder-induced localization of ultra-cold atoms. This work studies the transport properties of matter waves in disordered optical potentials, which are also known as speckle potentials. The effect of correlated disorder on localization is first studied numerically in the framework of the Anderson model. The relevant transport parameters in the configuration average over many different realizations of the speckle potential are then determined analytically, using self-consistent diagrammatic perturbation techniques. This allows to make predictions for a possible experimental observation of coherent transport phenomena for cold atoms in speckle potentials. Of particular importance are the spatial correlations of the speckle fluctuations, which are responsible for the anisotropic character of the single scattering processes in the effective medium. Coherent multiple scattering leads to quantum interference effects, which entail a renormalization of the diffusion constant as compared to the classical description. This so-called weak localization of matter waves is studied as the underlying mechanism for the disorder-driven transition to the Anderson-localization regime, explicitly taking into account the correlations of the speckle fluctuations. (orig.)

  8. Optical pulse shaping approaches to coherent control

    International Nuclear Information System (INIS)

    Goswami, Debabrata

    2003-01-01

    The last part of the twentieth century has experienced a huge resurge of activity in the field of coherent light-matter interaction, more so in attempting to exert control over such interactions. Birth of coherent control was originally spurred by the theoretical understanding of the quantum interferences that lead to energy randomization and experimental developments in ultrafast laser spectroscopy. The theoretical predictions on control of reaction channels or energy randomization processes are still more dramatic than the experimental demonstrations, though this gap between the two is consistently reducing over the recent years with realistic theoretical models and technological developments. Experimental demonstrations of arbitrary optical pulse shaping have made some of the previously impracticable theoretical predictions possible to implement. Starting with the simple laser modulation schemes to provide proof-of-the-principle demonstrations, feedback loop pulse shaping systems have been developed that can actively manipulate some atomic and molecular processes. This tremendous experimental boost of optical pulse shaping developments has prospects and implications into many more new directions, such as quantum computing and terabit/sec data communications. This review captures certain aspects and impacts of optical pulse shaping into the fast developing areas of coherent control and other related fields. Currently available reviews focus on one or the other detailed aspects of coherent control, and the reader will be referred to such details as and when necessary for issues that are dealt in brief here. We will focus on the current issues including control of intramolecular dynamics and make connections to the future concepts, such as, quantum computation, biomedical applications, etc

  9. Differences Between a Single- and a Double-Folding Nucleus-9Be Optical Potential

    International Nuclear Information System (INIS)

    Bonaccorso, A.; Carstoiu, F.; Charity, R. J.; Kumar, R.; Salvioni, G.

    2016-01-01

    We have recently constructed two very successful n- 9 Be optical potentials (Bonaccorso and Charity in Phys Rev C89:024619, 2014). One by the Dispersive Optical Model (DOM) method and the other (AB) fully phenomenological. The two potentials have strong surface terms in common for both the real and the imaginary parts. This feature makes them particularly suitable to build a single-folded (light-) nucleus- 9 Be optical potential by using ab-initio projectile densities such as those obtained with the VMC method. On the other hand, a VMC density together with experimental nucleon–nucleon cross-sections can be used also to obtain a neutron and/or proton- 9 Be imaginary folding potential. We will use here an ab-initio VMC density to obtain both a n- 9 Be single-folded potential and a nucleus-nucleus double-folded potential. In this work we report on the cases of 8 B, 8 Li and 8 C projectiles. Our approach could be the basis for a systematic study of optical potentials for light exotic nuclei scattering on such light targets. Some of the projectiles studied are cores of other exotic nuclei for which neutron knockout has been used to extract spectroscopic information. For those cases, our study will serve to make a quantitative assessment of the core-target part of the reaction description, in particular its localization. (author)

  10. How deep is the antinucleon optical potential at FAIR energies

    International Nuclear Information System (INIS)

    Gaitanos, T.; Kaskulov, M.; Lenske, H.

    2011-01-01

    The key question in the interaction of antinucleons in the nuclear medium concerns the deepness of the antinucleon-nucleus optical potential. In this work we study this task in the framework of the non-linear derivative (NLD) model which describes consistently bulk properties of nuclear matter and Dirac phenomenology of nucleon-nucleus interactions. We apply the NLD model to antinucleon interactions in nuclear matter and find a strong decrease of the vector and scalar self-energies in energy and density and thus a strong suppression of the optical potential at zero momentum and, in particular, at FAIR energies. This is in agreement with available empirical information and, therefore, resolves the issue concerning the incompatibility of G-parity arguments in relativistic mean-field (RMF) models. We conclude the relevance of our results for the future activities at FAIR.

  11. Radiative charge transfer in He{sup +}+ H{sub 2} collisions in the milli- to nano-electron-volt range: A theoretical study within state-to-state and optical potential approaches

    Energy Technology Data Exchange (ETDEWEB)

    Mrugala, Felicja [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, PL 87-100 Torun (Poland); Kraemer, Wolfgang P. [Max-Planck-Institute of Astrophysics, Postfach 1317, D-85741 Garching (Germany)

    2013-03-14

    The paper presents a theoretical study of the low-energy dynamics of the radiative charge transfer (RCT) reaction He{sup +}({sup 2}S)+H{sub 2}(X{sup 1}{Sigma}{sub g}{sup +}){yields}He({sup 1}S)+H{sub 2}{sup +}(X{sup 2}{Sigma}{sub g}{sup +})+h{nu} extending our previous studies on radiative association of HeH{sub 2}{sup +} [F. Mrugala, V. Spirko, and W. P. Kraemer, J. Chem. Phys. 118, 10547 (2003); F. Mrugala and W. P. Kraemer, ibid. 122, 224321 (2005)]. The calculations account for the vibrational and rotational motions of the H{sub 2}/H{sub 2}{sup +} diatomics and for the atom-diatom complex formation in the reactant and the product channels of the RCT reaction. Continuum states of He{sup +}+ H{sub 2}(v= 0, j= 0) in the collision energy range {approx}10{sup -7}-18.6 meV and all quasi-bound states of the He{sup +}- H{sub 2}(para;v= 0) complex formed in this range are taken into account. Close-coupling calculations are performed to determine rates of radiative transitions from these states to the continuum and quasi-bound states of the He +H{sub 2}{sup +} system in the energy range extending up to {approx}0.16 eV above the opening of the HeH{sup +}+ H arrangement channel. From the detailed state-to-state calculated characteristics global functions of the RCT reaction, such as cross-section {sigma}(E), emission intensity I({nu}, T), and rate constant k(T) are derived, and are presented together with their counterparts for the radiative association (RA) reaction He{sup +}({sup 2}S) +H{sub 2}(X{sup 1}{Sigma}{sub g}{sup +}){yields} HeH{sub 2}{sup +}(X{sup 2}A{sup Prime })+h{nu}. The rate constant k{sup RCT} is approximately 20 times larger than k{sup RA} at the considered temperatures, 0.1 {mu}K-50 K. Formation of rotational Feshbach resonances in the reactant channel plays an important role in both reactions. Transitions mediated by these resonances contribute more than 70% to the respective rates. An extension of the one-dimensional optical potential model is

  12. Intermediate-energy nuclear photoabsorption and the pion optical potential

    International Nuclear Information System (INIS)

    Christillin, P.

    1984-01-01

    Nuclear photoabsorption around the pion threshold is schematised as photoproduction of a pion which undergoes final-stae interaction with the nucleus, accounted for by the pion optical potential. It is shown that real pion photoproduction and exchange effects are naturally described by the same mechanism with a non-static pion. The complementarity of photoabsorption to pion physics and its usefulness in gaining new information about pion-nucleus dynamics are stressed. (author)

  13. Field approach in the transformation optics concept

    DEFF Research Database (Denmark)

    Novitsky, Andrey; Zhukovsky, Sergei; Barkovsky, L. M.

    2012-01-01

    distribution (e.g., Gaussian and sinusoidal) is studied to validate the effectiveness of the field-based formulation. As for the boundary conditions for the cloaked region the absence of the normal component of the Poynting vector is justified. In the frames of the field-based approach the physical reasons...

  14. High-throughput proteomics : optical approaches.

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, George S.

    2008-09-01

    Realistic cell models could greatly accelerate our ability to engineer biochemical pathways and the production of valuable organic products, which would be of great use in the development of biofuels, pharmaceuticals, and the crops for the next green revolution. However, this level of engineering will require a great deal more knowledge about the mechanisms of life than is currently available. In particular, we need to understand the interactome (which proteins interact) as it is situated in the three dimensional geometry of the cell (i.e., a situated interactome), and the regulation/dynamics of these interactions. Methods for optical proteomics have become available that allow the monitoring and even disruption/control of interacting proteins in living cells. Here, a range of these methods is reviewed with respect to their role in elucidating the interactome and the relevant spatial localizations. Development of these technologies and their integration into the core competencies of research organizations can position whole institutions and teams of researchers to lead in both the fundamental science and the engineering applications of cellular biology. That leadership could be particularly important with respect to problems of national urgency centered around security, biofuels, and healthcare.

  15. Current use and potential of additive manufacturing for optical applications

    Science.gov (United States)

    Brunelle, Matthew; Ferralli, Ian; Whitsitt, Rebecca; Medicus, Kate

    2017-10-01

    Additive manufacturing, or 3D printing, has become widely used in recent years for the creation of both prototype and end-use parts. Because the parts are created in a layer-by-layer manner, the flexibility of additive manufacturing is unparalleled and has opened the design space to enable features like undercuts and internal channels which cannot exist on traditional, subtractively manufactured parts. This flexibility can also be leveraged for optical applications. This paper outlines some of the current uses of 3D printing in the optical manufacturing process at Optimax. Several materials and additive technologies are utilized, including polymer printing through fused deposition modeling, which creates parts by depositing a softened thermoplastic filament in a layerwise fashion. Stereolithography, which uses light to cure layers of a photopolymer resin, will also be discussed. These technologies are used to manufacture functional prototypes, fixtures, sealed housings, and other components. Additionally, metal printing through selective laser melting, which uses a laser to melt metal powder layers into a dense solid, will be discussed due to the potential to manufacture thermally stable opticalmechanical assembly frameworks and functional optics. Examples of several additively manufactured optical components will be shown.

  16. Nucleus-Nucleus Scattering in the High-Energy Approximation and the Optical Folding Potential

    CERN Document Server

    Lukyanov, V K; Lukyanov, K V

    2004-01-01

    For the nucleus-nucleus scattering, the complex potential is obtained which corresponds to the eikonal phase of an optical limit of the Glauber-Sitenko high-energy approximation. The potential does not include free parameters, its real and imaginary parts depend on energy and are determined by the reported data on the nuclear density distributions and nucleon-nucleon scattering amplitude. Alternatively, for the real part, the folding potential can be utilized which includes the effective NN-forces and the exchange term, as well. As a result, the microscopic optical potential is constructed where contributions of the calculated real and imaginary parts are formed by fitting the two respective factors. An efficient of the approach is confirmed by agreements of calculations with the experimental data on elastic scattering cross-sections.

  17. Microscopic optical potentials derived from ab initio translationally invariant nonlocal one-body densities

    Science.gov (United States)

    Gennari, Michael; Vorabbi, Matteo; Calci, Angelo; Navrátil, Petr

    2018-03-01

    Background: The nuclear optical potential is a successful tool for the study of nucleon-nucleus elastic scattering and its use has been further extended to inelastic scattering and other nuclear reactions. The nuclear density of the target nucleus is a fundamental ingredient in the construction of the optical potential and thus plays an important role in the description of the scattering process. Purpose: In this paper we derive a microscopic optical potential for intermediate energies using ab initio translationally invariant nonlocal one-body nuclear densities computed within the no-core shell model (NCSM) approach utilizing two- and three-nucleon chiral interactions as the only input. Methods: The optical potential is derived at first order within the spectator expansion of the nonrelativistic multiple scattering theory by adopting the impulse approximation. Nonlocal nuclear densities are derived from the NCSM one-body densities calculated in the second quantization. The translational invariance is generated by exactly removing the spurious center-of-mass (COM) component from the NCSM eigenstates. Results: The ground-state local and nonlocal densities of He 4 ,6 ,8 , 12C, and 16O are calculated and applied to optical potential construction. The differential cross sections and the analyzing powers for the elastic proton scattering off these nuclei are then calculated for different values of the incident proton energy. The impact of nonlocality and the COM removal is discussed. Conclusions: The use of nonlocal densities has a substantial impact on the differential cross sections and improves agreement with experiment in comparison to results generated with the local densities especially for light nuclei. For the halo nuclei 6He and 8He, the results for the differential cross section are in a reasonable agreement with the data although a more sophisticated model for the optical potential is required to properly describe the analyzing powers.

  18. Linear and nonlinear intersubband optical absorption in a disk-shaped quantum dot with a parabolic potential plus an inverse squared potential in a static magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Liu Guanghui [Department of Physics, College of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510006 (China); Guo Kangxian, E-mail: axguo@sohu.com [Department of Physics, College of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510006 (China); Wang Chao [Institute of Public Administration, Guangzhou University, Guangzhou 510006 (China)

    2012-06-15

    The linear and nonlinear optical absorption in a disk-shaped quantum dot (DSQD) with parabolic potential plus an inverse squared potential in the presence of a static magnetic field are theoretically investigated within the framework of the compact-density-matrix approach and iterative method. The energy levels and the wave functions of an electron in the DSQD are obtained by using the effective mass approximation. Numerical calculations are presented for typical GaAs/AlAs DSQD. It is found that the optical absorption coefficients are strongly affected not only by a static magnetic field, but also by the strength of external field, the confinement frequency and the incident optical intensity.

  19. Linear and nonlinear intersubband optical absorption in a disk-shaped quantum dot with a parabolic potential plus an inverse squared potential in a static magnetic field

    International Nuclear Information System (INIS)

    Liu Guanghui; Guo Kangxian; Wang Chao

    2012-01-01

    The linear and nonlinear optical absorption in a disk-shaped quantum dot (DSQD) with parabolic potential plus an inverse squared potential in the presence of a static magnetic field are theoretically investigated within the framework of the compact-density-matrix approach and iterative method. The energy levels and the wave functions of an electron in the DSQD are obtained by using the effective mass approximation. Numerical calculations are presented for typical GaAs/AlAs DSQD. It is found that the optical absorption coefficients are strongly affected not only by a static magnetic field, but also by the strength of external field, the confinement frequency and the incident optical intensity.

  20. Potential applications of optical coherence tomography angiography in glaucoma.

    Science.gov (United States)

    Dastiridou, Anna; Chopra, Vikas

    2018-05-01

    Optical coherence tomography angiography (OCTA) is a novel, noninvasive imaging modality that allows assessment of the retinal and choroidal vasculature. The scope of this review is to summarize recent studies using OCTA in glaucoma and highlight potential applications of this new technology in the field of glaucoma. OCTA studies have shown that retinal vascular changes may not develop solely as a result of advanced glaucoma damage. OCTA-derived measurements have provided evidence for lower retinal vascular densities at the optic nerve head, peripapillary and macula in preperimetric-glaucoma and early-glaucoma, as well as, in more advanced glaucoma, in comparison to with normal eyes. OCTA is a novel imaging modality that has already started to expand our knowledge base regarding the role of ocular blood flow in glaucoma. Future studies will better elucidate the role of OCTA-derived measurements in clinical practice, research, and clinical trials in glaucoma.

  1. Optical computing - an alternate approach to trigger processing

    International Nuclear Information System (INIS)

    Cleland, W.E.

    1981-01-01

    The enormous rate reduction factors required by most ISABELLE experiments suggest that we should examine every conceivable approach to trigger processing. One approach that has not received much attention by high energy physicists is optical data processing. The past few years have seen rapid advances in optoelectronic technology, stimulated mainly by the military and the communications industry. An intriguing question is whether one can utilize this technology together with the optical computing techniques that have been developed over the past two decades to develop a rapid trigger processor for high energy physics experiments. Optical data processing is a method for performing a few very specialized operations on data which is inherently two dimensional. Typical operations are the formation of convolution or correlation integrals between the input data and information stored in the processor in the form of an optical filter. Optical processors are classed as coherent or incoherent, according to the spatial coherence of the input wavefront. Typically, in a coherent processor a laser beam is modulated with a photographic transparency which represents the input data. In an incoherent processor, the input may be an incoherently illuminated transparency, but self-luminous objects, such as an oscilloscope trace, have also been used. We consider here an incoherent processor in which the input data is converted into an optical wavefront through the excitation of an array of point sources - either light emitting diodes or injection lasers

  2. Optical approaches to macroscopic and microscopic engineering

    International Nuclear Information System (INIS)

    Bartolo, Paulo Jorge da Silva

    2001-01-01

    This research investigates the theoretical basis of a new photo-fabrication system. By this system, optical and thermal effects are used, together or separately, to locally induce a phase change in a liquid resin. This phase change phenomena is used to 'write' three-dimensional shapes. In addition, a thermal-kinetic model has been developed to correctly simulate the physical and chemical changes that occur in the bulk (and surroundings) of the material directly exposed to radiation and/or heat, and the rates at which these changes occur. Through this model, the law of conservation of energy describing the heat transfer phenomena is coupled with a kinetic model describing in detail the cure kinetics in both chemical and diffusion-controlled regimes. The thermal-kinetic model has been implemented using the finite element method. Linear rectangular elements have been considered and the concept of isoparametric formulation used. The Cranck-Nicolson algorithm has been used to integrate the system of equations, resulting from the finite element discretisation, with respect to time. Three different photo-fabrication processes were investigated. The first process uses ultraviolet radiation to cure a thermosetting polymer containing a certain amount of photo-initiator. The radiation generates free radicals by cleavage the initiator molecules, starting the chemical reaction. The second one uses ultraviolet radiation to start the curing reaction of a liquid thermosetting polymer containing a certain amount of photo-initiator. In this case, a heat source is also used to increase the temperature, and consequently, to increase the rate of gel formation and the fractional conversion, decreasing the necessary exposure time. Finally, the third system uses a thermosetting material containing small amounts of both thermal and photo-initiators. In this case ultraviolet radiation and heat are used to simultaneously start two types of chemical reactions: thermal-initiated and photo

  3. MEMS: A new approach to micro-optics

    Energy Technology Data Exchange (ETDEWEB)

    Sniegowski, J.J.

    1997-12-31

    MicroElectroMechanical Systems (MEMS) and their fabrication technologies provide great opportunities for application to micro-optical systems (MOEMS). Implementing MOEMS technology ranges from simple, passive components to complicated, active systems. Here, an overview of polysilicon surface micromachining MEMS combined with optics is presented. Recent advancements to the technology, which may enhance its appeal for micro-optics applications are emphasized. Of all the MEMS fabrication technologies, polysilicon surface micromachining technology has the greatest basis in and leverages the most the infrastructure for silicon integrated circuit fabrication. In that respect, it provides the potential for very large volume, inexpensive production of MOEMS. This paper highlights polysilicon surface micromachining technology in regards to its capability to provide both passive and active mechanical elements with quality optical elements.

  4. Building better optical model potentials for nuclear astrophysics applications

    International Nuclear Information System (INIS)

    Bauge, Eric; Dupuis, Marc

    2004-01-01

    In nuclear astrophysics, optical model potentials play an important role, both in the nucleosynthesis models, and in the interpretation of astrophysics related nuclear physics measurements. The challenge of nuclear astrophysics resides in the fact that it involves many nuclei far from the stability line, implying than very few (if any) experimental results are available for these nuclei. The answer to this challenge is a heavy reliance on microscopic optical models with solid microscopic physics foundations that can predict the relevant physical quantities with good accuracy. This use of microscopic information limits the likelihood of the model failing spectacularly (except if some essential physics was omitted in the modeling) when extrapolating away from the stability line, in opposition to phenomenological models which are only suited for interpolation between measured data points and not for extrapolating towards unexplored areas of the chart of the nuclides.We will show how these microscopic optical models are built, how they link to our present knowledge of nuclear structure, and how they affect predictions of nuclear astrophysics models and the interpretation of some key nuclear physics measurements for astrophysics

  5. Nonlinear Optics Approaches Towards Subdiffraction Resolution in CARS Imaging

    NARCIS (Netherlands)

    Boller, Klaus J.; Beeker, W.P.; Cleff, C.; Kruse, K.; Lee, Christopher James; Gross, P.; Offerhaus, Herman L.; Fallnich, Carsten; Herek, Jennifer Lynn; Fornasiero, E.F.; Rizzoli, S.O.

    2014-01-01

    In theoretical investigations, we review several nonlinear optical approaches towards subdiffraction-limited resolution in label-free imaging via coherent anti-Stokes Raman scattering (CARS). Using a density matrix model and numerical integration, we investigate various level schemes and

  6. Effective field theory approaches for tensor potentials

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Maximilian

    2016-11-14

    Effective field theories are a widely used tool to study physical systems at low energies. We apply them to systematically analyze two and three particles interacting via tensor potentials. Two examples are addressed: pion interactions for anti D{sup 0}D{sup *0} scattering to dynamically generate the X(3872) and dipole interactions for two and three bosons at low energies. For the former, the one-pion exchange and for the latter, the long-range dipole force induce a tensor-like structure of the potential. We apply perturbative as well as non-perturbative methods to determine low-energy observables. The X(3872) is of major interest in modern high-energy physics. Its exotic characteristics require approaches outside the range of the quark model for baryons and mesons. Effective field theories represent such methods and provide access to its peculiar nature. We interpret the X(3872) as a hadronic molecule consisting of neutral D and D{sup *} mesons. It is possible to apply an effective field theory with perturbative pions. Within this framework, we address chiral as well as finite volume extrapolations for low-energy observables, such as the binding energy and the scattering length. We show that the two-point correlation function for the D{sup *0} meson has to be resummed to cure infrared divergences. Moreover, next-to-leading order coupling constants, which were introduced by power counting arguments, appear to be essential to renormalize the scattering amplitude. The binding energy as well as the scattering length display a moderate dependence on the light quark masses. The X(3872) is most likely deeper bound for large light quark masses. In a finite volume on the other hand, the binding energy significantly increases. The dependence on the light quark masses and the volume size can be simultaneously obtained. For bosonic dipoles we apply a non-perturbative, numerical approach. We solve the Lippmann-Schwinger equation for the two-dipole system and the Faddeev

  7. Light scattering in porous materials: Geometrical optics and stereological approach

    International Nuclear Information System (INIS)

    Malinka, Aleksey V.

    2014-01-01

    Porous material has been considered from the point of view of stereology (geometrical statistics), as a two-phase random mixture of solid material and air. Considered are the materials having the refractive index with the real part that differs notably from unit and the imaginary part much less than unit. Light scattering in such materials has been described using geometrical optics. These two – the geometrical optics laws and the stereological approach – allow one to obtain the inherent optical properties of such a porous material, which are basic in the radiative transfer theory: the photon survival probability, the scattering phase function, and the polarization properties (Mueller matrix). In this work these characteristics are expressed through the refractive index of the material and the random chord length distribution. The obtained results are compared with the traditional approach, modeling the porous material as a pack of particles of different shapes. - Highlights: • Porous material has been considered from the point of view of stereology. • Properties of a two-phase random mixture of solid material and air are considered. • Light scattering in such materials has been described using geometrical optics. • The inherent optical properties of such a porous material have been obtained

  8. A new approach for the verification of optical systems

    Science.gov (United States)

    Siddique, Umair; Aravantinos, Vincent; Tahar, Sofiène

    2013-09-01

    Optical systems are increasingly used in microsystems, telecommunication, aerospace and laser industry. Due to the complexity and sensitivity of optical systems, their verification poses many challenges to engineers. Tra­ditionally, the analysis of such systems has been carried out by paper-and-pencil based proofs and numerical computations. However, these techniques cannot provide perfectly accurate results due to the risk of human error and inherent approximations of numerical algorithms. In order to overcome these limitations, we propose to use theorem proving (i.e., a computer-based technique that allows to express mathematical expressions and reason about them by taking into account all the details of mathematical reasoning) as an alternative to computational and numerical approaches to improve optical system analysis in a comprehensive framework. In particular, this paper provides a higher-order logic (a language used to express mathematical theories) formalization of ray optics in the HOL Light theorem prover. Based on the multivariate analysis library of HOL Light, we formalize the notion of light ray and optical system (by defining medium interfaces, mirrors, lenses, etc.), i.e., we express these notions mathematically in the software. This allows us to derive general theorems about the behavior of light in such optical systems. In order to demonstrate the practical effectiveness, we present the stability analysis of a Fabry-Perot resonator.

  9. Development of theoretical oxygen saturation calibration curve based on optical density ratio and optical simulation approach

    Science.gov (United States)

    Jumadi, Nur Anida; Beng, Gan Kok; Ali, Mohd Alauddin Mohd; Zahedi, Edmond; Morsin, Marlia

    2017-09-01

    The implementation of surface-based Monte Carlo simulation technique for oxygen saturation (SaO2) calibration curve estimation is demonstrated in this paper. Generally, the calibration curve is estimated either from the empirical study using animals as the subject of experiment or is derived from mathematical equations. However, the determination of calibration curve using animal is time consuming and requires expertise to conduct the experiment. Alternatively, an optical simulation technique has been used widely in the biomedical optics field due to its capability to exhibit the real tissue behavior. The mathematical relationship between optical density (OD) and optical density ratios (ODR) associated with SaO2 during systole and diastole is used as the basis of obtaining the theoretical calibration curve. The optical properties correspond to systolic and diastolic behaviors were applied to the tissue model to mimic the optical properties of the tissues. Based on the absorbed ray flux at detectors, the OD and ODR were successfully calculated. The simulation results of optical density ratio occurred at every 20 % interval of SaO2 is presented with maximum error of 2.17 % when comparing it with previous numerical simulation technique (MC model). The findings reveal the potential of the proposed method to be used for extended calibration curve study using other wavelength pair.

  10. Differences Between a Single- and a Double-Folding Nucleus-^{9}Be Optical Potential

    Science.gov (United States)

    Bonaccorso, A.; Carstoiu, F.; Charity, R. J.; Kumar, R.; Salvioni, G.

    2016-05-01

    We have recently constructed two very successful n-^9Be optical potentials (Bonaccorso and Charity in Phys Rev C89:024619, 2014). One by the Dispersive Optical Model (DOM) method and the other (AB) fully phenomenological. The two potentials have strong surface terms in common for both the real and the imaginary parts. This feature makes them particularly suitable to build a single-folded (light-) nucleus-^9Be optical potential by using ab-initio projectile densities such as those obtained with the VMC method (Wiringa http://www.phy.anl.gov/theory/research/density/). On the other hand, a VMC density together with experimental nucleon-nucleon cross-sections can be used also to obtain a neutron and/or proton-^9Be imaginary folding potential. We will use here an ab-initio VMC density (Wiringa http://www.phy.anl.gov/theory/research/density/) to obtain both a n-^9Be single-folded potential and a nucleus-nucleus double-folded potential. In this work we report on the cases of ^8B, ^8Li and ^8C projectiles. Our approach could be the basis for a systematic study of optical potentials for light exotic nuclei scattering on such light targets. Some of the projectiles studied are cores of other exotic nuclei for which neutron knockout has been used to extract spectroscopic information. For those cases, our study will serve to make a quantitative assessment of the core-target part of the reaction description, in particular its localization.

  11. Multifocal visual evoked potentials for quantifying optic nerve dysfunction in patients with optic disc drusen

    DEFF Research Database (Denmark)

    Malmqvist, Lasse; de Santiago, Luis; Boquete, Luciano

    2017-01-01

    and 22 control subjects were examined. Mean amplitude, mean inner ring (IR) amplitude (0.87-5.67° of visual field) and mean outer ring amplitude (5.68-24° of visual field) were calculated using signal-to-noise ratio (SNR) and peak-to-peak analysis. Monocular latency was calculated using second peak......PURPOSE: To explore the applicability of multifocal visual evoked potentials (mfVEPs) for research and clinical diagnosis in patients with optic disc drusen (ODD). This is the first assessment of mfVEP amplitude in patients with ODD. METHODS: MfVEP amplitude and latency from 33 patients with ODD......, full eye and IR. In the control group, SNR intersubject variability was 17.6% and second peak latency intersubject variability was 2.8%. CONCLUSION: Decreased mfVEP amplitude in patients with ODD suggests a direct mechanical compression of the optic nerve axons. Our results suggest that mfVEP amplitude...

  12. Alternative approach of developing all-optical Fredkin and Toffoli gates

    Science.gov (United States)

    Mandal, Dhoumendra; Mandal, Sumana; Garai, Sisir Kumar

    2015-09-01

    Reversible logic gates show potential roles in communication technology, and it has a wide area of applicability such as in sequential and combinational circuit of optical computing, optical signal processing, multi-valued logic operations, etc. because of its advantageous aspects of data-recovering capabilities, low power consumption, least power dissipation, faster speed of processing, less hardware complexity, etc. In a reversible logic gate not only the outputs can be determined from the inputs, but also the inputs can be uniquely recovered from the outputs. In this article an alternative approach has been made to develop three-input-output Fredkin and Toffoli gates using the frequency conversion property of semiconductor optical amplifier (SOA) and frequency-based beam routing by optical multiplexers and demultiplexers. Simulation results show the feasibility of our proposed scheme.

  13. Microscopic kaonic-atom optical potential in finite nuclei with Λ(1405) and Σ(1385) resonances

    International Nuclear Information System (INIS)

    Mizoguchi, Masaki; Hirenzaki, Satoru; Toki, Hiroshi

    1994-01-01

    We derive kaonic-atom optical potentials in finite nuclei microscopically by taking into account the K - NΛ(1405) and K - NΣ(1385) interactions. Using the microscopic optical potentials we solve kaonic atoms with the Klein-Gordon equation in momentum space and obtain the kaonic-atom level shifts and the widths. The experimental data are reproduced well. We discuss also phenomenological optical potentials and compare them with the microscopic ones. In addition, we derive optical potentials in the local-density approximation with the use of the finite-matter kaon self-energy. We find a similarity with the microscopic optical potential derived with finite geometry. (orig.)

  14. Polarizing Beam Splitter: A New Approach Based on Transformation Optics

    Science.gov (United States)

    Mueller, Jonhatan; Wegener, Martin

    Standard optical elements (e.g. lenses, prisms) are mostly designed of piecewise homogeneous and isotropic dielectrics. However, in theory one has far more possibilities to influence electromagnetic waves, namely all the components of the permittivity and permeability tensors. In the past few years, on the one hand, new micro fabrication methods allowed for new freedom in controlling of the optical parameters using so called artificial metamaterials. On the other hand, the theory of transformation optics has given a somewhat intuitive approach for the design of such structures. The most popular feature of this kind is certainly optical cloaking (i.e. [1,2]). However, the full capabilities of other transformation optical devices are far from being fully explored. In my work, I focused on pure dielectric structures in a non-resonant and therefore non-lossy regime. Although the relative permittivity one can achieve this way is limited by the available natural dielectrics, a broad spectrum of features can be realized.

  15. Algebraic approach to the Kratzer potential

    International Nuclear Information System (INIS)

    Setare, Mohammad R; Karimi, Ebrahim

    2007-01-01

    In this paper, the energy eigenvalues and the corresponding eigenfunctions are calculated for the Kratzer potential. Then we obtain the ladder operators for the one-dimensional (1D) and 3D Kratzer potential. Finally, we show that these operators satisfy the SU(2) commutation relation

  16. CRAPONE, Optical Model Potential Fit of Neutron Scattering Data

    International Nuclear Information System (INIS)

    Fabbri, F.; Fratamico, G.; Reffo, G.

    2004-01-01

    1 - Description of problem or function: Automatic search for local and non-local optical potential parameters for neutrons. Total, elastic, differential elastic cross sections, l=0 and l=1 strength functions and scattering length can be considered. 2 - Method of solution: A fitting procedure is applied to different sets of experimental data depending on the local or non-local approximation chosen. In the non-local approximation the fitting procedure can be simultaneously performed over the whole energy range. The best fit is obtained when a set of parameters is found where CHI 2 is at its minimum. The solution of the system equations is obtained by diagonalization of the matrix according to the Jacobi method

  17. A new approach to stitching optical metrology data

    Science.gov (United States)

    King, Christopher W.

    The next generation of optical instruments, including telescopes and imaging apparatus, will generate an increased requirement for larger and more complex optical forms. A major limiting factor for the production of such optical components is the metrology: how do we measure such parts and with respect to what reference datum This metrology can be thought of as part of a complete cycle in the production of optical components and it is currently the most challenging aspect of production. This thesis investigates a new and complete approach to stitching optical metrology data to extend the effective aperture or, in future, the dynamic range of optical metrology instruments. A practical approach is used to build up a complete process for stitching on piano and spherical parts. The work forms a basis upon which a stitching system for aspheres might be developed in the future, which is inherently more complicated. Beginning with a historical perspective and a review of optical polishing and metrology, the work presented relates the commercially available metrology instruments to the stitching process developed. The stitching is then performed by a numerical optimization routine that seeks to join together overlapping sub-aperture measurements by consideration of the aberrations introduced by the measurement scenario, and by the overlap areas between measurements. The stitching is part of a larger project, the PPARC Optical Manipulation and Metrology project, and was to benefit from new wavefront sensing technology developed by a project partner, and to be used for the sub-aperture measurement. Difficult mathematical problems meant that such a wavefront sensor was not avail able for this work and a work-around was therefore developed using commercial instruments. The techniques developed can be adapted to work on commercial ma chine platforms, and in partuicular, the OMAM NPL/UCL swing-arm profilometer described in chapter 5, or the computer controlled polishing machines

  18. An optical potential for the statically deformed actinide nuclei derived from a global spherical potential

    Science.gov (United States)

    Al-Rawashdeh, S. M.; Jaghoub, M. I.

    2018-04-01

    In this work we test the hypothesis that a properly deformed spherical optical potential, used within a channel-coupling scheme, provides a good description for the scattering data corresponding to neutron induced reactions on the heavy, statically deformed actinides and other lighter deformed nuclei. To accomplish our goal, we have deformed the Koning-Delaroche spherical global potential and then used it in a channel-coupling scheme. The ground-state is coupled to a sufficient number of inelastic rotational channels belonging to the ground-state band to ensure convergence. The predicted total cross sections, elastic and inelastic angular distributions are in good agreement with the experimental data. As a further test, we compare our results to those obtained by a global channel-coupled optical model whose parameters were obtained by fitting elastic and inelastic angular distributions in addition to total cross sections. Our results compare quite well with those obtained by the fitted, channel-coupled optical model. Below neutron incident energies of about 1MeV, our results show that scattering into the rotational excited states of the ground-state band plays a significant role in the scattering process and must be explicitly accounted for using a channel-coupling scheme.

  19. Rainbow-shift mechanism behind discrete optical-potential ambiguities

    International Nuclear Information System (INIS)

    Brandan, M.E.; McVoy, K.W.

    1991-01-01

    Some years ago, Drisko et al. suggested that the discrete ambiguity often encountered for elastic scattering optical potentials could be understood as being due to the interior or small-l S-matrix elements for two ''equivalent'' potentials differing in phase by 2π, l-by-l. We point out that the absence of this phase change for peripheral partial waves is equally essential, and suggest that a deeper understanding of the ambiguity may be achieved by viewing it as a consequence of a farside interference between interior and peripheral partial waves. It is this interference which produces the broad ''Airy maxima'' of a nuclear rainbow, and we show that a Drisko-type phase-shift increment δ l →(δ l +π) for low-l phases relative to the high-l ones is exactly what is needed to shift a farside rainbow pattern by one Airy maximum, thus providing an equivalent ''rainbow-shift'' interpretation of the discrete ambiguity. The physical importance of both interpretations lies in the fact that the existence of discrete ambiguities (as well as of nuclear rainbows) is explicit evidence for low-l transparency in nucleus-nucleus collisions. The essential role played by low partial waves explains why peripheral reactions have generally not proven helpful in resolving this ambiguity

  20. Temperature dependent relativistic microscopic optical potential and mean free paths of nucleons

    International Nuclear Information System (INIS)

    Han Yinlu; Shen Qingbiao; Zhuo Yizhong

    1993-01-01

    The relativistic microscopic optical potential, mean free paths and Schroedinger equivalent potential of nucleons at finite temperature in nuclear matter are studied based on Walecka's model and thermo field dynamics. We let only the Hartree-Fock self-energy of nucleon represent to be the real part of the microscopic optical potential and the fourth order of meson exchange diagrams, i.e. the core polarization represent the imaginary part of microscopic optical potential in nuclear matter. The microscopic optical potential of finite nuclei is obtained with the local density approximation

  1. Calculation of the Huang-Rhys parameter in spherical quantum dots: the optical deformation potential effect

    International Nuclear Information System (INIS)

    Hamma, M; Miranda, R P; Vasilevskiy, M I; Zorkani, I

    2007-01-01

    An accurate calculation of the exciton-phonon interaction matrix elements and Huang-Rhys parameter for nearly spherical nanocrystals (NCs) of polar semiconductor materials is presented. The theoretical approach is based on a continuum lattice dynamics model and the effective mass approximation for electronic states in the NCs. A strong confinement regime is considered for both excitons and optical phonons, taking into account both the Froehlich-type and optical deformation potential (ODP) mechanisms of the exciton-phonon interaction. The effects of exchange electron-hole interaction and possible hexagonal crystal structure of the underlying material are also taken into account. The theory is applied to CdSe and InP quantum dots. It is shown that the ODP mechanism, almost unimportant for CdSe, dominates the exciton-phonon coupling in small InP dots. The effect of the non-diagonal interaction, not included in the Huang-Rhys parameter, is briefly discussed

  2. Multifocal fluorescence microscope for fast optical recordings of neuronal action potentials.

    Science.gov (United States)

    Shtrahman, Matthew; Aharoni, Daniel B; Hardy, Nicholas F; Buonomano, Dean V; Arisaka, Katsushi; Otis, Thomas S

    2015-02-03

    In recent years, optical sensors for tracking neural activity have been developed and offer great utility. However, developing microscopy techniques that have several kHz bandwidth necessary to reliably capture optically reported action potentials (APs) at multiple locations in parallel remains a significant challenge. To our knowledge, we describe a novel microscope optimized to measure spatially distributed optical signals with submillisecond and near diffraction-limit resolution. Our design uses a spatial light modulator to generate patterned illumination to simultaneously excite multiple user-defined targets. A galvanometer driven mirror in the emission path streaks the fluorescence emanating from each excitation point during the camera exposure, using unused camera pixels to capture time varying fluorescence at rates that are ∼1000 times faster than the camera's native frame rate. We demonstrate that this approach is capable of recording Ca(2+) transients resulting from APs in neurons labeled with the Ca(2+) sensor Oregon Green Bapta-1 (OGB-1), and can localize the timing of these events with millisecond resolution. Furthermore, optically reported APs can be detected with the voltage sensitive dye DiO-DPA in multiple locations within a neuron with a signal/noise ratio up to ∼40, resolving delays in arrival time along dendrites. Thus, the microscope provides a powerful tool for photometric measurements of dynamics requiring submillisecond sampling at multiple locations. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  3. Thermally induced micro-motion by inflection in optical potential

    Czech Academy of Sciences Publication Activity Database

    Šiler, Martin; Jákl, Petr; Brzobohatý, Oto; Ryabov, A.; Filip, R.; Zemánek, Pavel

    2017-01-01

    Roč. 7, MAY (2017), s. 1-8, č. článku 1697. ISSN 2045-2322 R&D Projects: GA ČR GB14-36681G; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : molecular motors * brownian-motion * manipulation * efficiency * tweezers Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 4.259, year: 2016

  4. The potential of optical coherence tomography for diagnosing meniscal pathology

    Science.gov (United States)

    Hang-Yin Ling, Carrie; Pozzi, Antonio; Thieman, Kelley M.; Tonks, Catherine A.; Guo, Shuguang; Xie, Huikai; Horodyski, MaryBeth

    2010-04-01

    Meniscal tears are often associated with anterior cruciate ligament (ACL) injury and may lead to pain and discomfort in humans. Maximal preservation of meniscal tissue is highly desirable to mitigate the progression of osteoarthritis. Guidelines of which meniscal tears are amenable to repair and what part of damaged tissues should be removed are elusive and lacking consensus. Images of microstructural changes in meniscus would potentially guide the surgeons to manage the meniscal tears better, but the resolution of current diagnostic techniques is limited for this application. In this study, we demonstrated the feasibility of using optical coherence tomography (OCT) for the diagnosis of meniscal pathology. Torn medial menisci were collected from dogs with ACL insufficiency. The torn meniscus was divided into three tissue samples and scanned by OCT and scanning electron microscopy (SEM). OCT and SEM images of torn menisci were compared. Each sample was evaluated for gross and microstructural abnormalities and reduction or loss of birefringence from the OCT images. The abnormalities detected with OCT were described for each type of tear. OCT holds promise in non-destructive and fast assessment of microstructural changes and tissue birefringence of meniscal tears. Future development of intraoperative OCT may help surgeons in the decision making of meniscal treatment.

  5. The potential of optical coherence tomography for diagnosing meniscal pathology

    International Nuclear Information System (INIS)

    Ling, Carrie Hang-Yin; Horodyski, MaryBeth; Pozzi, Antonio; Thieman, Kelley M; Tonks, Catherine A; Guo, Shuguang; Xie, Huikai

    2010-01-01

    Meniscal tears are often associated with anterior cruciate ligament (ACL) injury and may lead to pain and discomfort in humans. Maximal preservation of meniscal tissue is highly desirable to mitigate the progression of osteoarthritis. Guidelines of which meniscal tears are amenable to repair and what part of damaged tissues should be removed are elusive and lacking consensus. Images of microstructural changes in meniscus would potentially guide the surgeons to manage the meniscal tears better, but the resolution of current diagnostic techniques is limited for this application. In this study, we demonstrated the feasibility of using optical coherence tomography (OCT) for the diagnosis of meniscal pathology. Torn medial menisci were collected from dogs with ACL insufficiency. The torn meniscus was divided into three tissue samples and scanned by OCT and scanning electron microscopy (SEM). OCT and SEM images of torn menisci were compared. Each sample was evaluated for gross and microstructural abnormalities and reduction or loss of birefringence from the OCT images. The abnormalities detected with OCT were described for each type of tear. OCT holds promise in non-destructive and fast assessment of microstructural changes and tissue birefringence of meniscal tears. Future development of intraoperative OCT may help surgeons in the decision making of meniscal treatment

  6. Osteopetroses, emphasizing potential approaches to treatment.

    Science.gov (United States)

    Teti, Anna; Econs, Michael J

    2017-09-01

    interfering RNA approach and novel pharmacologic treatments. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. The investigation of relativistic microscopic optical potential based on RBBG equation

    International Nuclear Information System (INIS)

    Chen Baoqiu; Ma Zhongyu

    1992-01-01

    The relativistic microscopic optical potential is derived from the RBBG equation. The nucleon complex effective mass is determined phenomenologically by a fit to 200 MeV proton-nucleus scattering data. Then the relativistic microscopic optical potentials of proton scattered from different targets: 16 O, 40 Ca, 90 Zr and 208 Pb in the energies range from 160 to 800 MeV have been got. The relativistic microscopic optical potentials have been used to study proton- 40 Ca scattering at 200 MeV. Theoretical predictions for cross section and spin observables are compared with experimental data and phenomenological Dirac optical potential

  8. Development of global medium-energy nucleon-nucleus optical model potentials

    International Nuclear Information System (INIS)

    Madland, D.G.; Sierk, A.J.

    1997-01-01

    The authors report on the development of new global optical model potentials for nucleon-nucleus scattering at medium energies. Using both Schroedinger and Dirac scattering formalisms, the goal is to construct a physically realistic optical potential describing nucleon-nucleus elastic scattering observables for a projectile energy range of (perhaps) 20 meV to (perhaps) 2 GeV and a target mass range of 16 to 209, excluding regions of strong nuclear deformation. They use a phenomenological approach guided by conclusions from recent microscopic studies. The experimental database consists largely of proton-nucleus elastic differential cross sections, analyzing powers, spin-rotation functions, and total reaction cross sections, and neutron-nucleus total cross sections. They will use this database in a nonlinear least-squares adjustment of optical model parameters in both relativistic equivalent Schroedinger (including relativistic kinematics) and Dirac (second-order reduction) formalisms. Isospin will be introduced through the standard Lane model and a relativistic generalization of that model

  9. Exactly Solvable Quantum Mechanical Potentials: An Alternative Approach.

    Science.gov (United States)

    Pronchik, Jeremy N.; Williams, Brian W.

    2003-01-01

    Describes an alternative approach to finding exactly solvable, one-dimensional quantum mechanical potentials. Differs from the usual approach in that instead of starting with a particular potential and seeking solutions to the related Schrodinger equations, it begins with known solutions to second-order ordinary differential equations and seeks to…

  10. Computational Approach for Studying Optical Properties of DNA Systems in Solution

    DEFF Research Database (Denmark)

    Nørby, Morten Steen; Svendsen, Casper Steinmann; Olsen, Jógvan Magnus Haugaard

    2016-01-01

    In this paper we present a study of the methodological aspects regarding calculations of optical properties for DNA systems in solution. Our computational approach will be built upon a fully polarizable QM/MM/Continuum model within a damped linear response theory framework. In this approach...... the environment is given a highly advanced description in terms of the electrostatic potential through the polarizable embedding model. Furthermore, bulk solvent effects are included in an efficient manner through a conductor-like screening model. With the aim of reducing the computational cost we develop a set...... of averaged partial charges and distributed isotropic dipole-dipole polarizabilities for DNA suitable for describing the classical region in ground-state and excited-state calculations. Calculations of the UV-spectrum of the 2-aminopurine optical probe embedded in a DNA double helical structure are presented...

  11. Progress in the development of global medium-energy nucleon-nucleus optical model potentials

    International Nuclear Information System (INIS)

    Madland, D.G.

    1997-01-01

    Two existing global medium-energy nucleon-nucleus phenomenological optical model potentials are described and compared with experiment and with each other. The first of these employs a Dirac approach (second-order reduction) that is global in projectile energy and projectile isospin and applies to the target nucleus 208 Pb. The second of these employs a relativistic equivalent to the Schroedinger equation (including relativistic kinematics) that is global in projectile energy, projectile isospin, and target (Z,A). Finally, current work is described and the influence of the nuclear bound state problem (treated in relativistic mean field theory) on the Dirac scattering problem is mentioned. Spherical target nuclei are treated in the present work and strongly-collective target nuclei (rotational and vibrational) requiring coupled-channels approaches will be treated in a future paper. (author)

  12. Neutron optical potential of 28Si derived from the dispersion relation

    International Nuclear Information System (INIS)

    Kitazawa, H.; Igarasi, S.; Katsuragi, D.; Harima, Y.

    1992-01-01

    Based upon the dispersion theory, an optical potential of 28 Si was determined at the neutron energies from the Fermi energy to 20 MeV. In particular, discussion was given on a characteristic behavior of the optical potential for low-energy neutrons. Moreover, the validity of the dispersion theory was investigated for neutron single-particle bound states in 29 Si. (orig.)

  13. The use of dispersion relations to construct unified nucleon optical potentials

    International Nuclear Information System (INIS)

    Hodgson, P.E.

    1991-01-01

    The dispersion relations provide a simple and accurate way of parametrizing the optical potential for a particular nucleus over a range of energies. A method is proposed for obtaining a global nucleon optical potential incorporating the dispersion relations. (author). 9 refs, 3 figs

  14. Potential for integrated optical circuits in advanced aircraft with fiber optic control and monitoring systems

    Science.gov (United States)

    Baumbick, Robert J.

    1991-02-01

    Fiber optic technology is expected to be used in future advanced weapons platforms as well as commercial aerospace applications. Fiber optic waveguides will be used to transmit noise free high speed data between a multitude of computers as well as audio and video information to the flight crew. Passive optical sensors connected to control computers with optical fiber interconnects will serve both control and monitoring functions. Implementation of fiber optic technology has already begun. Both the military and NASA have several programs in place. A cooperative program called FOCSI (Fiber Optic Control System Integration) between NASA Lewis and the NAVY to build environmentally test and flight demonstrate sensor systems for propul sion and flight control systems is currently underway. Integrated Optical Circuits (IOC''s) are also being given serious consideration for use in advanced aircraft sys tems. IOC''s will result in miniaturization and localization of components to gener ate detect optical signals and process them for use by the control computers. In some complex systems IOC''s may be required to perform calculations optically if the technology is ready replacing some of the electronic systems used today. IOC''s are attractive because they will result in rugged components capable of withstanding severe environments in advanced aerospace vehicles. Manufacturing technology devel oped for microelectronic integrated circuits applied to IOC''s will result in cost effective manufacturing. This paper reviews the current FOCSI program and describes the role of IOC''s in FOCSI applications.

  15. Scattered Data Processing Approach Based on Optical Facial Motion Capture

    Directory of Open Access Journals (Sweden)

    Qiang Zhang

    2013-01-01

    Full Text Available In recent years, animation reconstruction of facial expressions has become a popular research field in computer science and motion capture-based facial expression reconstruction is now emerging in this field. Based on the facial motion data obtained using a passive optical motion capture system, we propose a scattered data processing approach, which aims to solve the common problems of missing data and noise. To recover missing data, given the nonlinear relationships among neighbors with the current missing marker, we propose an improved version of a previous method, where we use the motion of three muscles rather than one to recover the missing data. To reduce the noise, we initially apply preprocessing to eliminate impulsive noise, before our proposed three-order quasi-uniform B-spline-based fitting method is used to reduce the remaining noise. Our experiments showed that the principles that underlie this method are simple and straightforward, and it delivered acceptable precision during reconstruction.

  16. Peroperative optical autofluorescence biopsy-verification of its diagnostic potential

    Czech Academy of Sciences Publication Activity Database

    Ducháč, V.; Zavadil, Jiří; Vránová, J.; Jirásek, T.; Štukavec, J.; Horák, L.

    2011-01-01

    Roč. 26, č. 3 (2011), s. 325-333 ISSN 0268-8921 Institutional research plan: CEZ:AV0Z20670512 Keywords : Autofluorescence spectroscopy * Colorectal cancer * Optical fibres Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.004, year: 2011

  17. On the relationship between optical variability, visual saliency, and eye fixations: a computational approach.

    Science.gov (United States)

    Garcia-Diaz, Antón; Leborán, Víctor; Fdez-Vidal, Xosé R; Pardo, Xosé M

    2012-06-12

    A hierarchical definition of optical variability is proposed that links physical magnitudes to visual saliency and yields a more reductionist interpretation than previous approaches. This definition is shown to be grounded on the classical efficient coding hypothesis. Moreover, we propose that a major goal of contextual adaptation mechanisms is to ensure the invariance of the behavior that the contribution of an image point to optical variability elicits in the visual system. This hypothesis and the necessary assumptions are tested through the comparison with human fixations and state-of-the-art approaches to saliency in three open access eye-tracking datasets, including one devoted to images with faces, as well as in a novel experiment using hyperspectral representations of surface reflectance. The results on faces yield a significant reduction of the potential strength of semantic influences compared to previous works. The results on hyperspectral images support the assumptions to estimate optical variability. As well, the proposed approach explains quantitative results related to a visual illusion observed for images of corners, which does not involve eye movements.

  18. Optical fibre temperature sensor technology and potential application in absorbed dose calorimetry

    International Nuclear Information System (INIS)

    Allen, P.D.; Hargrave, N.J.

    1992-09-01

    Optical fibre based sensors are proposed as a potential alternative to the thermistors traditionally used as temperature sensors in absorbed dose calorimetry. The development of optical fibre temperature sensor technology over the last ten years is reviewed. The potential resolution of various optical techniques is assessed with particular reference to the requirements of absorbed dose calorimetry. Attention is drawn to other issues which would require investigation before the development of practical optical fibre sensors for this purpose could occur. 192 refs., 5 tabs., 4 figs

  19. Energy-efficient virtual optical network mapping approaches over converged flexible bandwidth optical networks and data centers.

    Science.gov (United States)

    Chen, Bowen; Zhao, Yongli; Zhang, Jie

    2015-09-21

    In this paper, we develop a virtual link priority mapping (LPM) approach and a virtual node priority mapping (NPM) approach to improve the energy efficiency and to reduce the spectrum usage over the converged flexible bandwidth optical networks and data centers. For comparison, the lower bound of the virtual optical network mapping is used for the benchmark solutions. Simulation results show that the LPM approach achieves the better performance in terms of power consumption, energy efficiency, spectrum usage, and the number of regenerators compared to the NPM approach.

  20. A Deep Learning Approach to Digitally Stain Optical Coherence Tomography Images of the Optic Nerve Head.

    Science.gov (United States)

    Devalla, Sripad Krishna; Chin, Khai Sing; Mari, Jean-Martial; Tun, Tin A; Strouthidis, Nicholas G; Aung, Tin; Thiéry, Alexandre H; Girard, Michaël J A

    2018-01-01

    To develop a deep learning approach to digitally stain optical coherence tomography (OCT) images of the optic nerve head (ONH). A horizontal B-scan was acquired through the center of the ONH using OCT (Spectralis) for one eye of each of 100 subjects (40 healthy and 60 glaucoma). All images were enhanced using adaptive compensation. A custom deep learning network was then designed and trained with the compensated images to digitally stain (i.e., highlight) six tissue layers of the ONH. The accuracy of our algorithm was assessed (against manual segmentations) using the dice coefficient, sensitivity, specificity, intersection over union (IU), and accuracy. We studied the effect of compensation, number of training images, and performance comparison between glaucoma and healthy subjects. For images it had not yet assessed, our algorithm was able to digitally stain the retinal nerve fiber layer + prelamina, the RPE, all other retinal layers, the choroid, and the peripapillary sclera and lamina cribrosa. For all tissues, the dice coefficient, sensitivity, specificity, IU, and accuracy (mean) were 0.84 ± 0.03, 0.92 ± 0.03, 0.99 ± 0.00, 0.89 ± 0.03, and 0.94 ± 0.02, respectively. Our algorithm performed significantly better when compensated images were used for training (P deep learning algorithm can simultaneously stain the neural and connective tissues of the ONH, offering a framework to automatically measure multiple key structural parameters of the ONH that may be critical to improve glaucoma management.

  1. The two-potential approach to one-proton emission

    International Nuclear Information System (INIS)

    Al-Khalili, J. S.; Cannon, A. J.; Stevenson, P. D.

    2007-01-01

    Proton decay half-lives can be calculated reliably using the idea of simple tunnelling probabilities within a WKB model. Just as simple, but much more intuitive is the approach of Gurvitz and Kalbermann of splitting the tunnelling potential into internal (bound state) and external (scattering state) parts. This is referred to as the Two-Potential approach to the tunnelling problem. For spherical nuclei there is not much to choose between TPA and WKB, but to extract reliable spectroscopic information from the dripline nuclei of interest, these methods must be extended to deformed potentials. We outline our approach for the case of spherical nuclei starting from a mean field HF potential using the Skyrme interaction and outline a programme of work leading to an extended 3-D TPA model

  2. Bone Marrow-Derived Cells as a Therapeutic Approach to Optic Nerve Diseases

    Directory of Open Access Journals (Sweden)

    Louise A. Mesentier-Louro

    2016-01-01

    Full Text Available Following optic nerve injury associated with acute or progressive diseases, retinal ganglion cells (RGCs of adult mammals degenerate and undergo apoptosis. These diseases have limited therapeutic options, due to the low inherent capacity of RGCs to regenerate and due to the inhibitory milieu of the central nervous system. Among the numerous treatment approaches investigated to stimulate neuronal survival and axonal extension, cell transplantation emerges as a promising option. This review focuses on cell therapies with bone marrow mononuclear cells and bone marrow-derived mesenchymal stem cells, which have shown positive therapeutic effects in animal models of optic neuropathies. Different aspects of available preclinical studies are analyzed, including cell distribution, potential doses, routes of administration, and mechanisms of action. Finally, published and ongoing clinical trials are summarized.

  3. The imaginary part of the local potential equivalent to the non-local α-nucleus optical potential

    International Nuclear Information System (INIS)

    Lassaut, M.; Vinh Mau, N.

    1982-01-01

    A simple expression of the α-nucleus optical potential has been derived from the Feshbach formula by using a closure approximation for summing over the excited states of the target nucleus. It has been shown that the correction to the real folding model potential is small. The imaginary local potential equivalent to the non-local Feshbach potential has been studied in detail for Ca nuclei and shown to reproduce quite well the gross properties of empirical potentials above 100 MeV with, however, a lack of absorption in the surface region. The A-dependence of the imaginary potential volume integral has also been investigated. (orig.)

  4. Polaron effects on nonlinear optical rectification in asymmetrical Gaussian potential quantum wells with applied electric fields

    International Nuclear Information System (INIS)

    Wu, Jinghe; Guo, Kangxian; Liu, Guanghui

    2014-01-01

    Polaron effects on nonlinear optical rectification in asymmetrical Gaussian potential quantum wells are studied by the effective mass approximation and the perturbation theory. The numerical results show that nonlinear optical rectification coefficients are strongly dependent on the barrier hight V 0 of the Gaussian potential quantum wells, the range L of the confinement potential and the electric field F. Besides, the numerical results show that no matter how V 0 , L and F change, taking into consideration polaron effects, the optical rectification coefficients χ 0 (2) get greatly enhanced.

  5. Global dependence of optical potential parameters for alpha particles with energies up to 80 MeV

    International Nuclear Information System (INIS)

    Kuterbekov, K.A.; Zholdybaev, T.K.; Sadykov, B.M.; Mukhambetzhan, A.; Kukhtina, I.N.; Penionzhkevich, Yu.Eh.

    2002-01-01

    Global (energy and mass) dependences of optical potential for α-particles with energies up to 80 MeV have been received. A Woods-Saxon form factor for macroscopic potential has been used. Energy and mass dependences of the semi-microscopic α-particle potential parameters have been investigated for the first time. In general, a good description of elastic and inelastic differential and total reactions cross sections for different nuclei using the revealed global parameters has been received within the framework of macroscopic and semi-microscopic approaches

  6. The value of art-oriented pedagogical approaches to the teaching of optics and photonics

    Science.gov (United States)

    Pompea, Stephen M.; Regens, Nancy L.

    2017-08-01

    Art-oriented pedagogical approaches have been successfully applied to optics and photonics education. We will describe how art-based programs that incorporate a Visual Thinking Strategies (VTS) approach can be used by optics and photonics educators. VTS encourages both a deep appreciation of the content of optics images and phenomena and a highly participatory approach to understanding them. This type of approach has been used by the authors in a variety of educational settings including teacher professional development workshops, museum and science center-based programs, after school programs and in two-week intensive summer academies for students. These approaches work well with multiple age groups including primary and secondary grade students, university students, and adults who may have little apparent connection to optics and photonics. This art-science hybrid approach can be used by university professors, optics/photonics professionals who do public programs, museum educators, and classroom science teachers.

  7. Noise and signal interference in optical fiber transmission systems an optimum design approach

    CERN Document Server

    Bottacchi, Stefano

    2008-01-01

    A comprehensive reference to noise and signal interference in optical fiber communications Noise and Signal Interference in Optical Fiber Transmission Systems is a compendium on specific topics within optical fiber transmission and the optimization process of the system design. It offers comprehensive treatment of noise and intersymbol interference (ISI) components affecting optical fiber communications systems, containing coverage on noise from the light source, the fiber and the receiver. The ISI is modeled with a statistical approach, leading to new useful computational m

  8. Contribution to the heavy-ion optical potential from coupling to vibrational states

    Energy Technology Data Exchange (ETDEWEB)

    Donangelo, R; Canto, L F; Hussein, M S

    1978-11-01

    The component of the optical potential in the elastic channel due to the coupling to vibrational states in Coulomb excitation is derived using a previously developed semiclassical method. Several numerical examples are worked out.

  9. An investigation of relativistic microscopic optical potential in terms of relativistic Brueckner-Bethe-Goldstone equation

    International Nuclear Information System (INIS)

    Chen Baoqiu; Ma Zhongyu

    1992-01-01

    Relativistic microscopic optical potential of nucleon-nucleus is derived from the relativistic Brueckner-Bethe-Goldstone (RBBG) equation. The complex effective mass of a nucleon is determined by a fit to 200 MeV p- 40 Ca scattering data. The relativistic microscopic optical potentials with this effective mass are obtained from RBBG for p- 16O , 40 Ca, 90 Zr and 208 Pb scattering in energy range from 160 to 800 MeV. The microscopic optical potential is used to study the proton- 40 Ca scattering problem at 200 MeV. The results, such as differential cross section, analyzing power and spin rotation function are compared with those calculated from phenomenological relativistic optical potential

  10. MRI findings and correlative study of MRI and visual evoked potentials in optic neuritis

    International Nuclear Information System (INIS)

    Yan Fei; Li Jing; Wang Zhenchang; Liu Shoubin; Zhang Xiaojun

    2008-01-01

    Objective: To investigate the effective MRI sequences and describe the correlation between MRI and visual evoked potential (VEP) in diagnosing optic neuritis. Methods: One hundred and fifty-four eyes with visual impairment of 98 patients with diagnoses of optic neuritis, papillitis, multiple sclerosis and Devic's disease underwent MRI and VEP examination. The MRI findings were analyzed and correlated with VEP results and clinical presentation by using X 2 test, wilco xon test and Kappa test. Results Out of the 154 sick eyes, 56 eyes presented thickened optic nerves, 76 eyes had normal diameter of the optic nerve, and 22 eyes had thin optic nerves. A total of 132 optic nerves showed abnormally high signal in STIR sequences, including involvement of intraocular segment in 7, intraorbital segment in 1.35, intracanalicular segment in 109, intracranial segment in 97, optic chiasm in 56, and optic tract in 23. A total of 54 patients underwent postcontrast MRI. Seventy-four optic nerves of 87 eyes showed enhancement. Among the 196 eyes of 98 patients, 132 eyes presented visual impairment and simultaneous abnormal MR signal of the optic nerve, and 26 eyes had both normal vision and normal MR signal of optic nerve. The consistency of MRI findings and vision status was 80. 61% (Kappa 0.453,P 1 -weighted MR sequence combined with fat- suppression are helpful in diagnosis of optic neuritis. VEP is helpful in diagnosing optic neuritis and in finding subclinical visual problem. The MRI combined with VEP could improve the diagnostic accuracy of optic neuritis. (authors)

  11. Comparing Different Approaches to Visualizing Light Waves: An Experimental Study on Teaching Wave Optics

    Science.gov (United States)

    Mešic, Vanes; Hajder, Erna; Neumann, Knut; Erceg, Nataša

    2016-01-01

    Research has shown that students have tremendous difficulties developing a qualitative understanding of wave optics, at all educational levels. In this study, we investigate how three different approaches to visualizing light waves affect students' understanding of wave optics. In the first, the conventional, approach light waves are represented…

  12. Multifocal visual evoked potentials in optic neuritis and multiple sclerosis

    DEFF Research Database (Denmark)

    Pihl-Jensen, Gorm; Schmidt, Mathias Falck; Frederiksen, Jette Lautrup

    2017-01-01

    published studies were retrieved). Mf-VEP provides direct topographical information of specific lesions and facilitates investigations on structural-functional correlations thus providing new methods for exploring the interplay between demyelination, atrophy and remyelination in MS. Good correlation...... was shown between mf-VEP and OCT, ff-VEP, MRI (MTR, DTI), 30-2 standard automated perimetry and low-contrast-visual acuity. All but one study showed superior sensitivity and specificity compared to ff-VEP, especially with regards to small, peripheral lesions or lesions of the upper visual field. Mf-VEP has...... shown superior sensitivity and specificity than established methods in diagnosing optic nerve lesions and tracking functional recovery following lesions. Abnormal mf-VEP responses in the fellow, non-ON afflicted eye may predict MS risk in ON patients. No standardization currently exists and no direct...

  13. Optical properties of potential condensates in exoplanetary atmospheres

    Science.gov (United States)

    Kitzmann, Daniel; Heng, Kevin

    2018-03-01

    The prevalence of clouds in currently observable exoplanetary atmospheres motivates the compilation and calculation of their optical properties. First, we present a new open-source Mie scattering code known as LX-MIE, which is able to consider large-size parameters (˜107) using a single computational treatment. We validate LX-MIE against the classical MIEVO code as well as previous studies. Secondly, we embark on an expanded survey of the published literature for both the real and imaginary components of the refractive indices of 32 condensate species. As much as possible, we rely on experimental measurements of the refractive indices and resort to obtaining the real from the imaginary component (or vice versa), via the Kramers-Kronig relation, only in the absence of data. We use these refractive indices as input for LX-MIE to compute the absorption, scattering and extinction efficiencies of all 32 condensate species. Finally, we use a three-parameter function to provide convenient fits to the shape of the extinction efficiency curve. We show that the errors associated with these simple fits in the Wide Field Camera 3 (WFC3), J, H, and K wavebands are ˜ 10 per cent. These fits allow for the extinction cross-section or opacity of the condensate species to be easily included in retrieval analyses of transmission spectra. We discuss prospects for future experimental work. The compilation of the optical constants and LX-MIE is publicly available as part of the open-source Exoclime Simulation Platform (http://www.exoclime.org).

  14. Zeta-function approach to Casimir energy with singular potentials

    International Nuclear Information System (INIS)

    Khusnutdinov, Nail R.

    2006-01-01

    In the framework of zeta-function approach the Casimir energy for three simple model system: single delta potential, step function potential and three delta potentials are analyzed. It is shown that the energy contains contributions which are peculiar to the potentials. It is suggested to renormalize the energy using the condition that the energy of infinitely separated potentials is zero which corresponds to subtraction all terms of asymptotic expansion of zeta-function. The energy obtained in this way obeys all physically reasonable conditions. It is finite in the Dirichlet limit, and it may be attractive or repulsive depending on the strength of potential. The effective action is calculated, and it is shown that the surface contribution appears. The renormalization of the effective action is discussed

  15. A variational approach to nonlinear evolution equations in optics

    Indian Academy of Sciences (India)

    optics. D ANDERSON, M LISAK and A BERNTSON£. Department of Electromagnetics, Chalmers University of Technology, SE-41296 Göteborg, Sweden. £Ericsson Telcom ... Many works in nonlinear optics have made efficient ...... focusing dynamics of a laser beam (or a Bose–Einstein condensate) in a parabolic external.

  16. Understanding electron magnetic circular dichroism in a transition potential approach

    Science.gov (United States)

    Barthel, J.; Mayer, J.; Rusz, J.; Ho, P.-L.; Zhong, X. Y.; Lentzen, M.; Dunin-Borkowski, R. E.; Urban, K. W.; Brown, H. G.; Findlay, S. D.; Allen, L. J.

    2018-04-01

    This paper introduces an approach based on transition potentials for inelastic scattering to understand the underlying physics of electron magnetic circular dichroism (EMCD). The transition potentials are sufficiently localized to permit atomic-scale EMCD. Two-beam and three-beam systematic row cases are discussed in detail in terms of transition potentials for conventional transmission electron microscopy, and the basic symmetries which arise in the three-beam case are confirmed experimentally. Atomic-scale EMCD in scanning transmission electron microscopy (STEM), using both a standard STEM probe and vortex beams, is discussed.

  17. Density of states in an optical speckle potential

    International Nuclear Information System (INIS)

    Falco, G. M.; Fedorenko, A. A.; Giacomelli, J.; Modugno, M.

    2010-01-01

    We study the single-particle density of states of a one-dimensional speckle potential, which is correlated and non-Gaussian. We consider both the repulsive and the attractive cases. The system is controlled by a single dimensionless parameter determined by the mass of the particle, the correlation length, and the average intensity of the field. Depending on the value of this parameter, the system exhibits different regimes, characterized by the localization properties of the eigenfunctions. We calculate the corresponding density of states using the statistical properties of the speckle potential. We find good agreement with the results of numerical simulations.

  18. Multi-modal approach using Raman spectroscopy and optical coherence tomography for the discrimination of colonic adenocarcinoma from normal colon

    Science.gov (United States)

    Ashok, Praveen C.; Praveen, Bavishna B.; Bellini, Nicola; Riches, Andrew; Dholakia, Kishan; Herrington, C. Simon

    2013-01-01

    We report a multimodal optical approach using both Raman spectroscopy and optical coherence tomography (OCT) in tandem to discriminate between colonic adenocarcinoma and normal colon. Although both of these non-invasive techniques are capable of discriminating between normal and tumour tissues, they are unable individually to provide both the high specificity and high sensitivity required for disease diagnosis. We combine the chemical information derived from Raman spectroscopy with the texture parameters extracted from OCT images. The sensitivity obtained using Raman spectroscopy and OCT individually was 89% and 78% respectively and the specificity was 77% and 74% respectively. Combining the information derived using the two techniques increased both sensitivity and specificity to 94% demonstrating that combining complementary optical information enhances diagnostic accuracy. These data demonstrate that multimodal optical analysis has the potential to achieve accurate non-invasive cancer diagnosis. PMID:24156073

  19. Thermally Stable Heterocyclic Imines as New Potential Nonlinear Optical Materials

    Science.gov (United States)

    Nesterov, Volodymyr V.; Antipin, Mikhail Y.; Nesterov, Vladimir N.; Moore, Craig E.; Cardelino, Beatriz H.; Timofeeva, Tatiana V.

    2004-01-01

    In the course of a search for new thermostable acentric nonlinear optical crystalline materials, several heterocyclic imine derivatives were designed, with the general structure D-pi-A(D'). Introduction of a donor amino group (D') into the acceptor moiety was expected to bring H-bonds into their crystal structures, and so to elevate their melting points and assist in an acentric molecular packing. Six heterocycle-containing compounds of this type were prepared, single crystals were grown for five of them, and these crystals were characterized by X-ray analysis. A significant melting temperature elevation was found for all of the synthesized compounds. Three of the compounds were also found to crystallize in acentric space groups. One of the acentric compounds is built as a three-dimensional H-bonded molecular network. In the other two compounds, with very similar molecular structure, the molecules form one-dimensional H-bonded head-to-head associates (chains). These chains are parallel in two different crystallographic directions and form very unusual interpenetrating chain patterns in an acentric crystal. Two of the compounds crystallized with centrosymmetric molecular packing.

  20. Interfacial potential approach for Ag/ZnO (0001) interfaces

    International Nuclear Information System (INIS)

    Song Hong-Quan; Shen Jiang; Qian Ping; Chen Nan-Xian

    2014-01-01

    Systematic approaches are presented to extract the interfacial potentials from the ab initio adhesive energy of the interface system by using the Chen—Möbius inversion method. We focus on the interface structure of the metal (111)/ZnO (0001) in this work. The interfacial potentials of Ag—Zn and Ag—O are obtained. These potentials can be used to solve some problems about Ag/ZnO interfacial structure. Three metastable interfacial structures are investigated in order to check these potentials. Using the interfacial potentials we study the procedure of interface fracture in the Ag/ZnO (0001) interface and discuss the change of the energy, stress, and atomic structures in tensile process. The result indicates that the exact misfit dislocation reduces the total energy and softens the fracture process. Meanwhile, the formation and mobility of the vacancy near the interface are observed. (condensed matter: structural, mechanical, and thermal properties)

  1. Information on pion-nucleus optical potentials from elastic scattering

    International Nuclear Information System (INIS)

    Friedman, E.

    1983-02-01

    Data on the elastic scattering of pions by nuclei between 20 and 230 MeV is analyzed in an almost model-independent fashion. The real part of the potential, which is described by a bias-free Fourier-Bessel series, is found to have the typical Kisslinger or Laplacian-like shape between 30 and 80 MeV

  2. Asymmetry dependence of Gogny-based optical potential

    Energy Technology Data Exchange (ETDEWEB)

    Blanchon, G.; Dupuis, M.; Bernard, R.N. [CEA, DAM, DIF, Arpajon (France); Arellano, H.F. [University of Chile, Department of Physics - FCFM, Santiago (Chile); CEA, DAM, DIF, Arpajon (France)

    2017-05-15

    An analysis of neutron and proton scattering off {sup 40,48}Ca has been carried out. Real and imaginary potentials have been generated using the Nuclear Structure Method (NSM) for scattering with the Gogny D1S nucleon-nucleon effective interaction. Observables are well described by NSM for neutron and proton elastic scattering off {sup 40}Ca and for neutron scattering off {sup 48}Ca. For proton scattering off {sup 48}Ca, NSM yields a lack of absorption. This discrepancy is attributed to two-fold charge exchange (p, n, p) contribution and coupling to Gamow-Teller mode which are not included in the present version of NSM. A recipe based on a Perey-Buck fit of the NSM imaginary potential and Lane model is proposed to overcome this issue in an approximate way. (orig.)

  3. A Real Time AI Approach to Discrimination Boost Phase Optical Sensor Systems in SDI Architectures

    Science.gov (United States)

    Sloggett, David R.

    1990-04-01

    Interest has been rekindled in the potential utility of Ballistic Missile Defence (BMD) systems 1,2 and their ability to enhance the existing NATO strategic defence posture 3,4. Whereas in the past BMD systems have been thought to be vulnerable to relatively simple offence countermeasures, technological developments that have occurred over the past 20 years offer the potential to solve some of the main criticisms that have bedeviled BMD research since its inception in the early 1950s. One of the key areas where dramatic developments have taken place is in the field of electro-optic sensor technologies where developments in device sensitivity and packing density offer new solutions to threat detection, tracking and discrimination that complement data traditionally associated with radar based systems. Analysis has shown 5 that optical sensor systems can make a significant contribution to threat analysis in the boost and mid course phases of flight of ballistic missile systems. In the Boost phase the large amounts of energy contained within the plume of a ballistic missile system provides a signature that must be detected against cloud and earth backgrounds - necessitating viewing from space. The process of detection is complicated by reflected sunlight and other sources of false alarms. The optical sensor systems must therefore be adaptable and capable of reasoning about the location of the signatures, their persistence and temporal variations. Much of this processing is ideally carried out at the sensor system - in order to eliminate false alarms and reduce the communications bandwidths required to transfer the sensor data to centralised early warning and battle management facilities. In the mid course phase optical sensor systems can be used to detect warm objects against the background of deep space. These sensor systems can form tracks on these objects that can be merged into 3D tracks as data from individual sensor systems are combined. As closely spaced objects

  4. Heuristic approach to the passive optical network with fibre duct ...

    African Journals Online (AJOL)

    Integer programming, network flow optimisation, passive optical network, ... This paper uses concepts from network flow optimisation to incorporate fibre duct shar ... [4] studied the survivable constrained ConFL problem and solved a number of.

  5. A possible approach on optical analogues of gravitational attractors

    KAUST Repository

    San-Romá n-Alerigi, Damiá n P.; Ben Slimane, Ahmed; Ng, Tien Khee; Alsunaidi, Mohammad; Ooi, Boon S.

    2013-01-01

    , for example, providing an on-demand time delay or optical memories. Furthermore, beyond their practical applications to photonics, these mappings set forth an attractive realm to construct a panoply of celestial mechanics analogies and experiments

  6. Analytic approach to dielectric optical bent slab waveguides

    Czech Academy of Sciences Publication Activity Database

    Hiremath, K. R.; Hammer, M.; Stoffer, R.; Prkna, Ladislav; Čtyroký, Jiří

    2005-01-01

    Roč. 37, 1/3 (2005), s. 37-61 ISSN 0306-8919 R&D Projects: GA ČR(CZ) GA102/05/0987 Grant - others:European Commission(XE) IST-2000-28018 NAIS Institutional research plan: CEZ:AV0Z20670512 Keywords : integrated optics * optical waveguide theory * modelling Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.688, year: 2005

  7. Path integral approach to electron scattering in classical electromagnetic potential

    International Nuclear Information System (INIS)

    Xu Chuang; Feng Feng; Li Ying-Jun

    2016-01-01

    As is known to all, the electron scattering in classical electromagnetic potential is one of the most widespread applications of quantum theory. Nevertheless, many discussions about electron scattering are based upon single-particle Schrodinger equation or Dirac equation in quantum mechanics rather than the method of quantum field theory. In this paper, by using the path integral approach of quantum field theory, we perturbatively evaluate the scattering amplitude up to the second order for the electron scattering by the classical electromagnetic potential. The results we derive are convenient to apply to all sorts of potential forms. Furthermore, by means of the obtained results, we give explicit calculations for the one-dimensional electric potential. (paper)

  8. PIPIT: a momentum space optical potential code for pions

    Energy Technology Data Exchange (ETDEWEB)

    Eisenstein, R A [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics; Tabakin, F [Pittsburgh Univ., Pa. (USA). Dept. of Physics

    1976-11-01

    Angular distributions for the elastic scattering of pions are generated by summing a partial wave series. The elastic T-matrix elements for each partial wave are obtained by solving a relativistic Lippmann-Schwinger equation in momentum space using a matrix inversion technique. Basically the Coulomb interaction is included exactly using the method of Vincent and Phatak. The ..pi..N amplitude is obtained from phase shift information on-shell and incorporates a separable off-shell form factor to ensure a physically reasonable off-shell extrapolation. The ..pi..N interaction is of finite range and a kinematic transformation procedure is used to express the ..pi..N amplitude in the ..pi.. nucleus frame. A maximum of 30 partial waves can be used in the present version of the program to calculate the cross section. The Lippmann-Schwinger equation is presently solved for each partial wave by inverting a 34x34 supermatrix. At very high energies, larger dimensions may be required. The present version of the code uses a separable non-local ..pi..N potential of finite range; other types of non-localities, or non-separable potentials, may be of physical interest.

  9. Coulomb effect in the tri nucleon system in an optical potential model

    International Nuclear Information System (INIS)

    Adhikari, S.K.; Delfino, A.; Maryland Univ., College Park, MD

    1993-02-01

    A Saxon-Woods type nucleon-deuteron optical potential in suggested and applied numerically to the study of the static Coulomb effect in the low-energy tri nucleon system. In particular, the observed correlations between the static Coulomb energy of 3 He and the triton binding energy, and that between the neutron-deuteron and the proton-deuteron scattering lengths are simulated with this optical potential. In view of this study and a previous one employing two other effective potentials its is unlikely that a a study of the usual static Coulomb effect in the tri nucleon system will reveal new and meaningful physics. (author). 12 refs, 2 figs

  10. Phenomenological and microscopic optical potentials for 88 MeV 7Li scattering

    International Nuclear Information System (INIS)

    Steeden, M.F.; Coopersmith, J.; Cartwright, S.J.; Cohler, M.D.; Clarke, N.M.; Griffiths, R.J.

    1980-01-01

    The elastic scattering cross sections for 88 MeV 7 Li ions have been measured for targets of 24 26 Mg and 40 48 Ca. Analyses using both phenomenological and microscopic optical potentials provide information on the energy dependence of optical parameters, and the extent to which the potentials are determined for these light ions. The use of a double-folding microscopic model demonstrates the need for normalisation of the real potential by a factor of 0.5 in contrast to measurements at lower energies. The contribution of exchange effects, density dependence and break-up are discussed. (author)

  11. Semiclassical derivation of a local optical potential for heavy-ion plastic scattering

    International Nuclear Information System (INIS)

    Donangelo, R.; Qanto, L.F.; Hussein, M.S.

    A semiclassical method to determine the contribution to the optical potential in the elastic channel due to the coupling to other processes taking place in heavy-ion collisions is developed. An application is made to the case of coulomb excitation. The lowest order term of our potential is shown to be identical to the quantum mechanical expression of Baltz et al

  12. Intermediate-energy proton- 4He elastic scattering with a microscopic optical potential

    International Nuclear Information System (INIS)

    Alexander, Y.; Landau, R.H.

    1979-01-01

    A microscopic, momentum space, optical potential calculation of elastic p- 4 He scattering is compared with 100-200 MeV data over the full angular range. The least sophisticated potential explains the occurrence and energy dependence of the back angle peak. (Auth.)

  13. Bayesian ensemble approach to error estimation of interatomic potentials

    DEFF Research Database (Denmark)

    Frederiksen, Søren Lund; Jacobsen, Karsten Wedel; Brown, K.S.

    2004-01-01

    Using a Bayesian approach a general method is developed to assess error bars on predictions made by models fitted to data. The error bars are estimated from fluctuations in ensembles of models sampling the model-parameter space with a probability density set by the minimum cost. The method...... is applied to the development of interatomic potentials for molybdenum using various potential forms and databases based on atomic forces. The calculated error bars on elastic constants, gamma-surface energies, structural energies, and dislocation properties are shown to provide realistic estimates...

  14. Effective and efficient optics inspection approach using machine learning algorithms

    International Nuclear Information System (INIS)

    Abdulla, G.; Kegelmeyer, L.; Liao, Z.; Carr, W.

    2010-01-01

    The Final Optics Damage Inspection (FODI) system automatically acquires and utilizes the Optics Inspection (OI) system to analyze images of the final optics at the National Ignition Facility (NIF). During each inspection cycle up to 1000 images acquired by FODI are examined by OI to identify and track damage sites on the optics. The process of tracking growing damage sites on the surface of an optic can be made more effective by identifying and removing signals associated with debris or reflections. The manual process to filter these false sites is daunting and time consuming. In this paper we discuss the use of machine learning tools and data mining techniques to help with this task. We describe the process to prepare a data set that can be used for training and identifying hardware reflections in the image data. In order to collect training data, the images are first automatically acquired and analyzed with existing software and then relevant features such as spatial, physical and luminosity measures are extracted for each site. A subset of these sites is 'truthed' or manually assigned a class to create training data. A supervised classification algorithm is used to test if the features can predict the class membership of new sites. A suite of self-configuring machine learning tools called 'Avatar Tools' is applied to classify all sites. To verify, we used 10-fold cross correlation and found the accuracy was above 99%. This substantially reduces the number of false alarms that would otherwise be sent for more extensive investigation.

  15. Phosphatidylinositol 4,5-bisphosphate optical uncaging potentiates exocytosis

    DEFF Research Database (Denmark)

    Walter, Alexander M; Müller, Rainer; Tawfik, Bassam

    2017-01-01

    Phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] is essential for exocytosis. Classical ways of manipulating PI(4,5)P2 levels are slower than metabolism, making it difficult to distinguish effects of PI(4,5)P2 from those of its metabolites. We developed a membrane-permeant, photoactivatable PI(4......,5)P2, which is loaded into cells in an inactive form and activated by light, allowing sub-second increases in PI(4,5)P2 levels. By combining this compound with electrophysiological measurements in mouse adrenal chromaffin cells, we show that PI(4,5)P2 uncaging potentiates exocytosis and identify...... synaptotagmin-1 (the Ca(2+) sensor for exocytosis) and Munc13-2 (a vesicle priming protein) as the relevant effector proteins. PI(4,5)P2 activation of exocytosis did not depend on the PI(4,5)P2-binding CAPS-proteins, suggesting that PI(4,5)P2 uncaging bypasses CAPS-function. Finally, PI(4,5)P2 uncaging...

  16. Genetic algorithm approach to thin film optical parameters determination

    International Nuclear Information System (INIS)

    Jurecka, S.; Jureckova, M.; Muellerova, J.

    2003-01-01

    Optical parameters of thin film are important for several optical and optoelectronic applications. In this work the genetic algorithm proposed to solve optical parameters of thin film values. The experimental reflectance is modelled by the Forouhi - Bloomer dispersion relations. The refractive index, the extinction coefficient and the film thickness are the unknown parameters in this model. Genetic algorithm use probabilistic examination of promissing areas of the parameter space. It creates a population of solutions based on the reflectance model and then operates on the population to evolve the best solution by using selection, crossover and mutation operators on the population individuals. The implementation of genetic algorithm method and the experimental results are described too (Authors)

  17. A possible approach on optical analogues of gravitational attractors

    KAUST Repository

    San-Román-Alerigi, Damián P.

    2013-04-01

    In this paper we report on the feasibility of light confinement in orbital geodesics on stationary, planar, and centro-symmetric refractive index mappings. Constrained to fabrication and [meta]material limitations, the refractive index, n, has been bounded to the range: 0.8 ? n(r) ? 3.5. Mappings are obtained through the inverse problem to the light geodesics equations, considering trappings by generalized orbit conditions defined a priori. Our simulation results show that the above mentioned refractive index distributions trap light in an open orbit manifold, both perennial and temporal, in regards to initial conditions. Moreover, due to their characteristics, these mappings could be advantageous to optical computing and telecommunications, for example, providing an on-demand time delay or optical memories. Furthermore, beyond their practical applications to photonics, these mappings set forth an attractive realm to construct a panoply of celestial mechanics analogies and experiments in the laboratory. © 2013 Optical Society of America.

  18. Separable potential approach in the folding model. Pt. 2

    International Nuclear Information System (INIS)

    Lee, C.L.; Robson, D.

    1982-01-01

    A microscopic folding formalism using a separable potential approach is applied to the elastic scattering of the n-α system. Starting with a separable nucleon-nucleon (NN) potential model, a sum of separable nucleon-nucleus potentials is obtained. A simple structure of the α-particle is assumed and the Tabakin, the Doleschall and the Strobel NN potentials are considered. These phenomenological interactions are of Yukawa or gaussian form with variable parameters for each partial wave. Spin-orbit and tensor forces are included. The resulting potentials developed from our folding calculations give approximately the same ssub(1/2) phase shifts for the n-α elastic scattering. However, in the psub(1/2) and psub(3/2) phase-shift analysis, an effective interaction derived from the NN potential is necessary to reproduce the resonances. One free energy independent parameter is introduced in our approximate G-matrix concept to give a good fit for the phase shifts. Single-nucleon knockout exchange (SNKE) is considered throughout. (orig.)

  19. QCD phase transition at real chemical potential with canonical approach

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Atsushi [RCNP, Osaka University,Osaka, 567-0047 (Japan); Nishina Center, RIKEN,Wako, Saitama 351-0198 (Japan); School of Biomedicine, Far Eastern Federal University,Vladivostok, 690950 (Russian Federation); Oka, Shotaro [Institute of Theoretical Physics, Department of Physics, Rikkyo University,Toshima-ku, Tokyo 171-8501 (Japan); Taniguchi, Yusuke [Graduate School of Pure and Applied Sciences, University of Tsukuba,Tsukuba, Ibaraki 305-8571 (Japan)

    2016-02-08

    We study the finite density phase transition in the lattice QCD at real chemical potential. We adopt a canonical approach and the canonical partition function is constructed for N{sub f}=2 QCD. After derivation of the canonical partition function we calculate observables like the pressure, the quark number density, its second cumulant and the chiral condensate as a function of the real chemical potential. We covered a wide range of temperature region starting from the confining low to the deconfining high temperature; 0.65T{sub c}≤T≤3.62T{sub c}. We observe a possible signal of the deconfinement and the chiral restoration phase transition at real chemical potential below T{sub c} starting from the confining phase. We give also the convergence range of the fugacity expansion.

  20. A Wave-Optics Approach to Paraxial Geometrical Laws Based on Continuity at Boundaries

    Science.gov (United States)

    Linares, J.; Nistal, M. C.

    2011-01-01

    We present a derivation of the paraxial geometrical laws starting from a wave-optics approach, in particular by using simple continuity conditions of paraxial spherical waves at boundaries (discontinuities) between optical media. Paraxial geometrical imaging and magnification laws, under refraction and reflection at boundaries, are derived for…

  1. Off-shell sensitivity, repulsive correlations and the pion-nucleus optical potential

    Energy Technology Data Exchange (ETDEWEB)

    Keister, B D [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics

    1977-07-01

    Repulsive nucleon-nucleon correlations tend to reduce the dependence of pion-nucleus elastic scattering upon the off-shell pion-nucleon dynamics. However, optical potential calculations can in practice be quite sensitive to the particular choice of off-shell model parameters. It is argued that this sensitivity results from the nature of the optical potential as a one-body operator which introduces extra off-shell dependence not found in physical many-body process itself. Thus, one must be very careful in any attempt to extract correlation or off-shell information, or to predict pion-nucleus phase shifts, by means of an optical potential theory. Results of model calculations are presented for purposes of illustration.

  2. Elastic scattering of 90 - 120 MeV 3He particles and unique optical potential

    International Nuclear Information System (INIS)

    Hyakutake, M.; Matoba, M.; Kumabe, I.; Fukada, M.; Komatuzaki, T.

    1978-01-01

    The elastic scattering of 109.2 MeV 3 He particles by 40 Ca, 58 Ni, 90 Zr and 116 Sn has been investigated over a wide angular range. The elastic scattering cross sections have been analyzed in terms of the optical model. The data for each nucleus studied were sufficient to eliminate the discrete ambiguity in the strength of the optical potential; the unique potential which fits the data has real well depth of about 100 MeV and a corresponding volume integral per nucleon pair of about 310 MeV fm 3 . The elastic scattering of 3 He particles by 58 Ni has been further measured at bombarding energies of 89.3 and 118.5 MeV, and the incident-energy dependence of the optical potential of 3 He particles for 58 Ni was obtained. (author)

  3. Evolution of colloidal dispersions in novel time-varying optical potentials

    Science.gov (United States)

    Koss, Brian Alan

    Optical traps use forces exerted by a tightly focused light beam to trap objects from tens of nanometers to tens of micrometers in size. Since their introduction in 1986, optical tweezers have become very useful to biology, chemistry, and soft condensed-matter physics. Work presented here, promises to advance optical tweezers not only in fundamental scientific research, but also in applications outside of the laboratory and into the mainstream of miniaturized manufacturing and diagnostics. By providing unprecedented access to the mesoscopic world, a new generation of optical traps, called Dynamic Holographic Optical Tweezers (HOTs) offers revolutionary new opportunities for fundamental and applied research. To demonstrate this technique, HOTs will be used to pump particles via a new method of transport called Optical Peristalsis (OP). OP is efficient method for transporting mesoscopic objects in three dimensions using short repetitive sequences of holographic optical trapping patterns. Transport in this process is analogous to peristaltic pumping, with the configurations of optical traps mimicking states of a peristaltic pump. While not limited to the deterministic particle transport, OP, can also be a platform to investigate the stochastic limit of particle transport. Advances in recent years have demonstrated that a variety of time-varying perturbations can induce drift in a diffusive system without exerting an overall force. Among these, are thermal ratchet models in which the system is subjected to time-varying energy landscapes that break spatiotemporal symmetry and thereby induce drift. Typically, the potential energy landscape is chosen to be the sawtooth potential. This work describes an alternate class of symmetric thermal ratchet models, that are not sawtooth, and demonstrates their efficacy in biasing the diffusion of colloidal spheres in both the stochastic and deterministic limits. Unlike previous models, each state in this thermal ratchet consists of

  4. The three-grating Mach-Zehnder optical interferometer: a tutorial approach using particle optics

    International Nuclear Information System (INIS)

    Miffre, A; Delhuille, R; Viaris Lesegno, B de; Buechner, M; Rizzo, C; Vigue, J

    2002-01-01

    In this paper, we present a tutorial set-up based on an optical three-grating Mach-Zehnder interferometer. As this apparatus is very similar in its principle to the Mach-Zehnder interferometers used with matter waves (neutrons, atoms and molecules), it can be used to familiarize students with particle optics, and in our explanations, we use the complementary points of view of wave optics and particle optics. Finally, we have used this interferometer to measure the index of refraction of BK7 glass for red light at 633 nm, with a technique equivalent to the one used to measure the index of refraction of solid matter for thermal neutrons. The dimensions of this interferometer and its cost make it very interesting for laboratory courses and the experiment described here can be reproduced by students

  5. A Novel Statistical Approach for Ocean Colour Estimation of Inherent Optical Properties and Cyanobacteria Abundance in Optically Complex Waters

    Directory of Open Access Journals (Sweden)

    Monika Soja-Woźniak

    2017-04-01

    Full Text Available Eutrophication is an increasing problem in coastal waters of the Baltic Sea. Moreover, algal blooms, which occur every summer in the Gulf of Gdansk can deleteriously impact human health, the aquatic environment, and economically important fisheries, tourism, and recreation industries. Traditional laboratory-based techniques for water monitoring are expensive and time consuming, which usually results in limited numbers of observations and discontinuity in space and time. The use of hyperspectral radiometers for coastal water observation provides the potential for more detailed remote optical monitoring. A statistical approach to develop local models for the estimation of optically significant components from in situ measured hyperspectral remote sensing reflectance in case 2 waters is presented in this study. The models, which are based on empirical orthogonal function (EOF analysis and stepwise multilinear regression, allow for the estimation of parameters strongly correlated with phytoplankton (pigment concentration, absorption coefficient and coloured detrital matter abundance (absorption coefficient directly from reflectance spectra measured in situ. Chlorophyll a concentration, which is commonly used as a proxy for phytoplankton biomass, was retrieved with low error (median percent difference, MPD = 17%, root mean square error RMSE = 0.14 in log10 space and showed a high correlation with chlorophyll a measured in situ (R = 0.84. Furthermore, phycocyanin and phycoerythrin, both characteristic pigments for cyanobacteria species, were also retrieved reliably from reflectance with MPD = 23%, RMSE = 0.23, R2 = 0.77 and MPD = 24%, RMSE = 0.15, R2 = 0.74, respectively. The EOF technique proved to be accurate in the derivation of the absorption spectra of phytoplankton and coloured detrital matter (CDM, with R2 (λ above 0.83 and RMSE around 0.10. The approach was also applied to satellite multispectral remote sensing reflectance data, thus allowing

  6. A Pragmatic Approach to Impairment Awareness in Optical Networks

    NARCIS (Netherlands)

    Iqbal, F.; Smets, R.; Kuipers, F.A.

    2015-01-01

    The points-of-presence of optical networks are interconnected by photonic paths capable of carrying Terabits of data. However, signals along those photonic paths accumulate transmission impairments and thus can be unreadable at the receiver if the accumulated impairments are too high. Our

  7. A simulator-based approach to evaluating optical trackers

    NARCIS (Netherlands)

    Smit, F.A.; Liere, van R.

    2009-01-01

    We describe a software framework to evaluate the performance of model-based optical trackers in virtual environments. The framework can be used to evaluate and compare the performance of different trackers under various conditions, to study the effects of varying intrinsic and extrinsic camera

  8. Remarks on the differential algebraic approach to particle beam optics by M. Berz

    International Nuclear Information System (INIS)

    Garczynski, V.

    1992-01-01

    The underlying mathematical structure of the differential algebraic approach of M. Berz to particle beam optics is isomorphic to the familiar truncated polynomial algebra. Concrete examples of derivations in this algebra, consistent with the truncation operation, are given

  9. Population of delayed-neutron granddaughter states and the optical potential

    International Nuclear Information System (INIS)

    Schenter, R.E.; Mann, F.M.; Warner, R.A.; Reeder, P.L.

    1982-08-01

    Using a statistical treatment of beta decay and the Hauser-Feshbach model of nuclear reactions, calculations were made and compared to recent experimental measurements of the population of granddaughter states of several delayed neutron precursors ( 144 145 147 Cs and 96 Rb). Emphasis of this paper is on the sensitivity and interpretation of experimental results to various standard low energy neutron optical model potentials and variations in their forms and parameters. Results for these precursors show qualitative agreement with experiment for all the optical potential models used and good quantitative agreement for two (Moldauer and Becchetti-Greenlees). Questions such as (N-Z) terms, deformation and nonlocality dependence are presented

  10. Temperature-dependent optical potential and mean free path based on Skyrme interactions

    International Nuclear Information System (INIS)

    Ge Lingxiao; Zhuo Yizhong; Noerenberg, W.; Technische Hochschule Darmstadt

    1986-03-01

    Optical potentials and mean free paths of nucleons at finite temperatures are studied by utilizing effective Skyrme interactions which yield 'good' optical potentials at zero temperature. The results for nuclear matter (symmetric and asymmetric) are applied within the local density approximation of finite nuclei at various temperatures. Because of the limitation due to zero-range forces used and the assumptions of temperature independent nuclear densities and effective Skyrme interactions made, the calculations are expected to be limited to nucleon energies between 10 and 50 MeV above the Fermi energy and to nuclear temperatures of less than 8 MeV. (orig.)

  11. Temperature-dependent relativistic microscopic optical potential and the mean free path of a nucleon based on Walecka's model

    International Nuclear Information System (INIS)

    Han Yinlu; Shen Qingbiao; Zhuo Yizhong

    1994-01-01

    The relativistic microscopic optical potential, the Schroedinger equivalent potential, and mean free paths of a nucleon at finite temperature in nuclear matter and finite nuclei are studied based on Walecka's model and thermo-field dynamics. We let only the Hartree-Fock self-energy of a nucleon represent the real part of the microscopic optical potential and the fourth order of meson exchange diagrams, i.e. the polarization diagrams represent the imaginary part of the microscopic optical potential in nuclear matter. The microscopic optical potential of finite nuclei is obtained by means of the local density approximation. (orig.)

  12. Special treatment of the optical potential of a spherical attractive fermi gas as a Saxon-Woods potential

    International Nuclear Information System (INIS)

    Grado-Caffaro, M.A.; Grado-Caffaro, M.

    2015-01-01

    Within a special scheme providing significant new results, we show that the (attractive) optical potential due to a spherical (non-relativistic) dilute and degenerate Fermi-Dirac gas becomes a Saxon-Woods potential which, in turn, is approximated by a truncated Dirac delta function near the center of the above spherical gas. This approximation is suitable to investigate phenomena in which fermions are restricted to move in relatively small spatial domains. In relation to this, we determine the corresponding fermion stationary wavefunctions which are found to be proportional to the aforementioned delta function if twice the fermion rest-mass multiplied by the total electron energy is much larger than the square of the reduced Planck constant. If this relationship is not fulfilled, the above fermion system is found to be roughly equivalent to fermions in an infinite one-dimensional potential well. In addition, the force field derived from the optical potential in question is determined as well as the chemical potential of the gas. Finally, application of our formulation to study electron transport in nanostructures is outlined

  13. Fourier synthesis of asymmetrical optical potentials for atoms; Fourier-Synthese von asymmetrischen optischen Potentialen fuer Atome

    Energy Technology Data Exchange (ETDEWEB)

    Ritt, G.

    2007-07-13

    In this work a dissipationless asymmetrical optical potential for cold atoms was produced. In a first step a new type of optical lattice was generated, whose spatial periodicity only corresponds to a quarter of the wavelength of the light used for the generation. This corresponds to the half of the periodicity of a conventional optical lattice, which is formed by the light of the same wavelength. The generation of this new type of optical lattice was reached by the use of two degenerated raman transitions. Virtual processes occur, in which four photons are involved. In conventional optical lattices however virtual two-photon processes occur. By spatially superimposing this optical lattice with a conventional optical lattice an asymmetrical optical potential could be formed. By diffraction of a Bose Einstein condensate of rubidium atoms at the transient activated asymmetrical potential the asymmetrical structure was proven. (orig.)

  14. Dissipation-Managed Bright Soliton in a 1D Bose-Einstein Condensate in an Optical-Lattice Potential

    International Nuclear Information System (INIS)

    Zhou Zheng; Yu Huiyou; Ao Shengmei; Yan Jiaren

    2010-01-01

    We study the formation of a dynamically-stabilized dissipation-managed bright soliton in a quasi-one-dimensional Bose-Einstein condensate by including an imaginary three-body recombination loss term and an imaginary linear feeding one in the Gross-Pitaevskii equation, trapped in a shallow optical-lattice potential. Based on the direct approach of perturbation theory for the nonlinear Schroedinger equation, we demonstrate that the height (as well as width) of bright soliton may have little change through selecting experimental parameters. (general)

  15. Adaptive Optical System for Retina Imaging Approaches Clinic Applications

    Science.gov (United States)

    Ling, N.; Zhang, Y.; Rao, X.; Wang, C.; Hu, Y.; Jiang, W.; Jiang, C.

    We presented "A small adaptive optical system on table for human retinal imaging" at the 3rd Workshop on Adaptive Optics for Industry and Medicine. In this system, a 19 element small deformable mirror was used as wavefront correction element. High resolution images of photo receptors and capillaries of human retina were obtained. In recent two years, at the base of this system a new adaptive optical system for human retina imaging has been developed. The wavefront correction element is a newly developed 37 element deformable mirror. Some modifications have been adopted for easy operation. Experiments for different imaging wavelengths and axial positions were conducted. Mosaic pictures of photoreceptors and capillaries were obtained. 100 normal and abnormal eyes of different ages have been inspected.The first report in the world concerning the most detailed capillary distribution images cover ±3° by ± 3° field around the fovea has been demonstrated. Some preliminary very early diagnosis experiment has been tried in laboratory. This system is being planned to move to the hospital for clinic experiments.

  16. Geometric and potential dynamics interpretation of the optic ring resonator bistability

    Science.gov (United States)

    Chiangga, S.; Chittha, T.; Frank, T. D.

    2015-07-01

    The optical bistability is a fundamental nonlinear feature of the ring resonator. A geometric and potential dynamics interpretation of the bistability is given. Accordingly, the bistability of the nonlinear system is shown to be a consequence of geometric laws of vector calculus describing the resonator ring. In contrast, the so-called transcendental relations that have been obtained in the literature in order to describe the optical wave are interpreted in terms of potential dynamical systems. The proposed novel interpretation provides new insights into the nature of the ring resonator optical bistability. The fundamental work by Rukhlenko, Premaratne and Agrawal (2010) as well as a more recent study by Chiangga, Pitakwongsaporn, Frank and Yupapin (2013) are considered.

  17. Van der Waals enhancement of optical atom potentials via resonant coupling to surface polaritons.

    Science.gov (United States)

    Kerckhoff, Joseph; Mabuchi, Hideo

    2009-08-17

    Contemporary experiments in cavity quantum electrodynamics (cavity QED) with gas-phase neutral atoms rely increasingly on laser cooling and optical, magneto-optical or magnetostatic trapping methods to provide atomic localization with sub-micron uncertainty. Difficult to achieve in free space, this goal is further frustrated by atom-surface interactions if the desired atomic placement approaches within several hundred nanometers of a solid surface, as can be the case in setups incorporating monolithic dielectric optical resonators such as microspheres, microtoroids, microdisks or photonic crystal defect cavities. Typically in such scenarios, the smallest atom-surface separation at which the van der Waals interaction can be neglected is taken to be the optimal localization point for associated trapping schemes, but this sort of conservative strategy generally compromises the achievable cavity QED coupling strength. Here we suggest a new approach to the design of optical dipole traps for atom confinement near surfaces that exploits strong surface interactions, rather than avoiding them, and present the results of a numerical study based on (39)K atoms and indium tin oxide (ITO). Our theoretical framework points to the possibility of utilizing nanopatterning methods to engineer novel modifications of atom-surface interactions. (c) 2009 Optical Society of America

  18. Localized second-order optical potential for electron scattering in terms of imaginary-frequency susceptibilities

    International Nuclear Information System (INIS)

    Valone, S.M.; Truhlar, D.G.; Thirumialai, D.

    1982-01-01

    A local approximation to the second-order optical potential for elastic scattering of low-energy electrons from ground-state atoms is expressed in terms of the imaginary-frequency susceptibilities of the atom due to a point charge and to modified perturbing potentials. This provides a basis for the physically appealing concept of regarding the perturbation due to the projectile as having a position-dependent effective frequency associated with it. The result is extended to higher energies with the use of the concept of a local kinetic energy. With a semiclassical approximation the result reduces to a simple general form that should be useful for model potential studies of electron-atom and electron-molecule scattering. Alternatively, variational functionals for the susceptibilities can be used to calculate the approximate optical potential most rigorously without making effective-frequency, average-kinetic-energy, or semiclassical approximations. Intermediate levels of rigor are also possible

  19. Microscopic local optical potentials and the nucleon–nucleus scattering at 65 MeV

    International Nuclear Information System (INIS)

    Haider, W.; Sharma, Manjari

    2010-01-01

    Microscopic local optical potentials from two sources were calculated by folding the numerical g-matrices over point proton and neutron RMF densities of target nuclei. The hard-core Hamada–Johnston and the soft-core Urbana v-14 local inter-nucleon potentials have been used to generate numerical g-matrices by solving Bethe–Goldstone integral equation. The calculated potentials have been used to analyze successfully both the proton and neutron differential elastic scattering and polarization data at 65 MeV over a wide mass region of targets: 12 C– 208 Pb. Comparison of the present results with a phenomenological optical model analyzes is also presented. Mass number dependence of the mean square radii of the two microscopic potentials are in close agreement with each other as well as with empirical results. (author)

  20. Proton optical potential and scattering matrix for tin nuclei at sub-coulomb energies

    International Nuclear Information System (INIS)

    Guzhovskij, B.Ya.; Dzyuba, B.M.

    1981-01-01

    A unified set of parameters of the proton optical potential (OP) for the n nuclei is searched for in the below-Coulomb-barrier energy range. The set must describe well the experimental data on the pn-reaction total cross sections and on the angular distributions of elastically scattered protons at E [ru

  1. Investigation of second-order optical potential for elastic π4He scattering

    International Nuclear Information System (INIS)

    Mach, R.; Sapozhnikov, M.G.

    1982-01-01

    The calculations of elastic π - 4 He scattering within the framework of the optical model with a second-order potential were performed. The effects of recoil correlations, charge exchange and double spin (isospin) flip in the inter-- mediate states are studied. The correction of the impulse approximation is investigated. Comparison between Kerman-McManus-Thaler and Watson formalisms is made

  2. Joint optimization of phase diversity and adaptive optics : Demonstration of potential

    NARCIS (Netherlands)

    Korkiakoski, V.; Keller, C.U.; Doelman, N.; Fraanje, P.R.; Verhaegen, M.H.G.

    2011-01-01

    We study different possibilities to use adaptive optics (AO) and phase diversity (PD) together in a jointly optimized system. The potential of the joint system is demonstrated through numerical simulations. We find that the most significant benefits are obtained from the improved deconvolution of

  3. The reactive content of the proton-nucleus impulse - approximation Dirac optical potential

    International Nuclear Information System (INIS)

    Carlson, B.V.; Isidro Filho, M.P.; Hussein, M.S.

    1984-01-01

    The total reaction cross sections for intermediate energy proton scattering on 40 Ca and 208 Pb are calculated within the Dirac-Eikonal formalism. Comparison with data indicate that the recently proposed impulse-approximation Dirac optical potential for nucleon-nucleus scattering, is not absorptive enough. (Author) [pt

  4. Semiclassical calculations of the imaginary part of the nucleon-nucleus optical potential

    International Nuclear Information System (INIS)

    Hasse, R.W.; Schuck, P.

    1984-03-01

    We calculate for finite nuclei the imaginary part of the nucleus-nucleon optical potential on and off shell by using the local Fermi gas approximation and a finite range two-body exchange force. Results are compared with those obtained by infinite nuclear matter calculations as well as using the local density or Glauber approximation

  5. Importance of the energy-dependent geometry in the 16O+ 16O optical model potential

    International Nuclear Information System (INIS)

    Pantis, G.; Ioannidis, K.; Poirier, P.

    1985-01-01

    Optical model potentials with various forms of energy-dependent geometry have been considered for the description of 16 O+ 16 O elastic scattering. It is shown that the variation with energy of the imaginary radius leads to a reasonable fit of the cross-section data, throughout the energy range

  6. Optical potential study of positron scattering by hydrogenic-type atoms

    International Nuclear Information System (INIS)

    Kuru Ratnavelu; Nithyanandan Natchimuthu; Kalai Kumar Rajgopal

    1999-01-01

    An optical potential method based on the close-coupling formalism has been implemented to study positron scattering by hydrogenic-type atoms. The present work will be reviewed in the context of other theories. Preliminary results will be presented and compared with experimental results. (author)

  7. Optical and x-ray alignment approaches for off-plane reflection gratings

    Science.gov (United States)

    Allured, Ryan; Donovan, Benjamin D.; DeRoo, Casey T.; Marlowe, Hannah R.; McEntaffer, Randall L.; Tutt, James H.; Cheimets, Peter N.; Hertz, Edward; Smith, Randall K.; Burwitz, Vadim; Hartner, Gisela; Menz, Benedikt

    2015-09-01

    Off-plane reflection gratings offer the potential for high-resolution, high-throughput X-ray spectroscopy on future missions. Typically, the gratings are placed in the path of a converging beam from an X-ray telescope. In the off-plane reflection grating case, these gratings must be co-aligned such that their diffracted spectra overlap at the focal plane. Misalignments degrade spectral resolution and effective area. In-situ X-ray alignment of a pair of off-plane reflection gratings in the path of a silicon pore optics module has been performed at the MPE PANTER beamline in Germany. However, in-situ X-ray alignment may not be feasible when assembling all of the gratings required for a satellite mission. In that event, optical methods must be developed to achieve spectral alignment. We have developed an alignment approach utilizing a Shack-Hartmann wavefront sensor and diffraction of an ultraviolet laser. We are fabricating the necessary hardware, and will be taking a prototype grating module to an X-ray beamline for performance testing following assembly and alignment.

  8. A 3D approach to reconstruct continuous optical images using lidar and MODIS

    Directory of Open Access Journals (Sweden)

    HuaGuo Huang

    2015-06-01

    Full Text Available Background Monitoring forest health and biomass for changes over time in the global environment requires the provision of continuous satellite images. However, optical images of land surfaces are generally contaminated when clouds are present or rain occurs. Methods To estimate the actual reflectance of land surfaces masked by clouds and potential rain, 3D simulations by the RAPID radiative transfer model were proposed and conducted on a forest farm dominated by birch and larch in Genhe City, DaXing’AnLing Mountain in Inner Mongolia, China. The canopy height model (CHM from lidar data were used to extract individual tree structures (location, height, crown width. Field measurements related tree height to diameter of breast height (DBH, lowest branch height and leaf area index (LAI. Series of Landsat images were used to classify tree species and land cover. MODIS LAI products were used to estimate the LAI of individual trees. Combining all these input variables to drive RAPID, high-resolution optical remote sensing images were simulated and validated with available satellite images. Results Evaluations on spatial texture, spectral values and directional reflectance were conducted to show comparable results. Conclusions The study provides a proof-of-concept approach to link lidar and MODIS data in the parameterization of RAPID models for high temporal and spatial resolutions of image reconstruction in forest dominated areas.

  9. Structural and optical properties of arsenic sulfide films synthesized by a novel PECVD-based approach

    Science.gov (United States)

    Mochalov, Leonid; Kudryashov, Mikhail; Logunov, Aleksandr; Zelentsov, Sergey; Nezhdanov, Aleksey; Mashin, Alexandr; Gogova, Daniela; Chidichimo, Giuseppe; De Filpo, Giovanni

    2017-11-01

    A new plasma-enhanced chemical vapor deposition-based (PECVD) approach for synthesizing of As-S films, with As content in the range 60-40 at.%, is demonstrated. The process has been carried out in a low-temperature Ar-plasma, employing for the first time volatile As and S as precursors. Utilization of inorganic elemental precursors, in contrast to the typically used in CVD metal-organic compounds or volatile hydrides/halides of Va- and VIa-group-elements, gives the possibility to reach the highest quality and purity of the As-S ≿halcogenide films. Quantum-chemical calculations have been performed to gain insight into the PECVD As-S chalcogenide films structure and the mechanism of its formation in the plasma discharge. An additional vibrational band near 650 cm-1 corresponding to cycled 2-dimensional units is observed by Raman spectroscopy. The process developed is cost-efficient one due to the very precise control and the long-term stability of the plasma parameters and it possesses a high potential for large-area applications such as fabrication of miniature integrated optical elements and 2D/3D printing of optical devices.

  10. An improved optical potential for low-energy pion-nucleus scattering

    International Nuclear Information System (INIS)

    Khankhasaev, M.Kh.; Topil'skaya, N.S.

    1988-01-01

    A new procedure for calculating the imaginary part the of Stricker, McManus and Carr (SMC) optical potential is proposed. It is based on an approximate expression for the pion-nucleon scattering amplitude including nuclear structure effects. It is shown that the resulting potential with the absorption parameters fitted to the pionic atom data provides a good description of the scattering up to 50 MeV

  11. Isospin term of the real part of the Lane optical-model potential

    International Nuclear Information System (INIS)

    Brandenberger, J.D.; Schrils, R.

    1976-01-01

    Previous neutron differential cross section measurements for Ni, Fe, and Co at 9 MeV are reanalyzed to obtain the isospin term in the real part of the Lane optical model potential employing a surface-centered form factor. The strength determined is 1.4 +- 0.2 MeV. It is further shown that analysis of the data is little affected by the choice of a volume or surface form for the isospin term in the real potential

  12. A spectral approach for the quantitative description of cardiac collagen network from nonlinear optical imaging.

    Science.gov (United States)

    Masè, Michela; Cristoforetti, Alessandro; Avogaro, Laura; Tessarolo, Francesco; Piccoli, Federico; Caola, Iole; Pederzolli, Carlo; Graffigna, Angelo; Ravelli, Flavia

    2015-01-01

    The assessment of collagen structure in cardiac pathology, such as atrial fibrillation (AF), is essential for a complete understanding of the disease. This paper introduces a novel methodology for the quantitative description of collagen network properties, based on the combination of nonlinear optical microscopy with a spectral approach of image processing and analysis. Second-harmonic generation (SHG) microscopy was applied to atrial tissue samples from cardiac surgery patients, providing label-free, selective visualization of the collagen structure. The spectral analysis framework, based on 2D-FFT, was applied to the SHG images, yielding a multiparametric description of collagen fiber orientation (angle and anisotropy indexes) and texture scale (dominant wavelength and peak dispersion indexes). The proof-of-concept application of the methodology showed the capability of our approach to detect and quantify differences in the structural properties of the collagen network in AF versus sinus rhythm patients. These results suggest the potential of our approach in the assessment of collagen properties in cardiac pathologies related to a fibrotic structural component.

  13. Microscopic optical model potential based on Brueckner-Hartree-Fock theory

    International Nuclear Information System (INIS)

    Li Lulu; Zhao Enguang; Zhou Shangui; Li Zenghua; Zuo Wei; Bonaccorso, Angela; Lonbardo, Umberto

    2010-01-01

    The optical model is one of the most important models in the study of nuclear reactions. In the optical model, the elastic channel is considered to be dominant and the contributions of all other absorption channels are described by introducing an imaginary potential, Koning and Delaroche obtained empirically the so-called KDR optical potentials based on a best-fitting of massive experimental data on nucleon-nucleus scattering reactions. The volume part is found to be dominant in the real component of the OMP at low energies. Using the Bruckner-Hartree-Fock theory with Bonn B potential plus self consistent three body force, the nucleon-nucleus optical potential is studied in this thesis. In the Bruckner theory, the on-shell self energy, is corresponding to the depth of the volume part of the optical model potential (OMP) for nucleon-nucleus scattering. Using Bruckner-Hartree-Fock theory, the nucleon on-shell self energy is calculated based on Hughenoltz-Van Hove (HVH) theorem. The microscopic optical potentials thus obtained agree well with the volume part of the KDR potentials. Furthermore, the isospin splitting in the volume part of the OMP is also reproduced satisfactorily. The isospin effect in the volume part of the OMP is directly related to the isospin splitting of the effective mass of the nucleon. According to our results, the isospin splitting of neutron to proton effective mass is such that the neutron effective mass increases with isospin, whereas the proton effective mass decreases. The isovector potential U n (E) - U p (E) vanishes at energy E ≈ 200 MeV and then changes sign indicating a possible inversion in the effective mass isospin spitting. We also calculated from the Bruckner theory the imaginary part of the OMP, and the microscopic calculations predict that the isospin splitting exists also in the imaginary OMP whereas the empirical KDR potentials do not show this feature. The shape of the real component of the nucleon-nucleus OMP is

  14. Colorectal cancer chemoprevention: the potential of a selective approach.

    Science.gov (United States)

    Ben-Amotz, Oded; Arber, Nadir; Kraus, Sarah

    2010-10-01

    Colorectal cancer (CRC) is a leading cause of cancer death, and therefore demands special attention. Novel recent approaches for the chemoprevention of CRC focus on selective targeting of key pathways. We review the study by Zhang and colleagues, evaluating a selective approach targeting APC-deficient premalignant cells using retinoid-based therapy and TNF-related apoptosis-inducing ligand (TRAIL). This study demonstrates that induction of TRAIL-mediated death signaling contributes to the chemopreventive value of all-trans-retinyl acetate (RAc) by sensitizing premalignant adenoma cells for apoptosis without affecting normal cells. We discuss these important findings, raise few points that deserve consideration, and may further contribute to the development of RAc-based combination therapies with improved efficacy. The authors clearly demonstrate a synergistic interaction between TRAIL, RAc and APC, which leads to the specific cell death of premalignant target cells. The study adds to the growing body of literature related to CRC chemoprevention, and provides solid data supporting a potentially selective approach for preventing CRC using RAc and TRAIL.

  15. Potential application of Chinese traditional medicine (CTM) as enhancer for tissue optical clearing

    Science.gov (United States)

    Chen, Wei; Jiang, Jingying; Wang, Ruikang K.; Xu, Kexin

    2009-02-01

    Many biocompatible hyperosmotic agents such as dimethyl sulfoxide(DMSO) have been used as enhancers for tissue optical clearing technique. However, previous investigations showed that DMSO can induce bradycardia, respiratory problems, and alterations in blood pressure. Also, DMSO could potentially alter the chemical structure, and hence the functional properties, of cell membranes. In this talk, Borneol among natural and nontoxic CTMs was introduced as new enhancer for optical clearing of porcine skin tissue since it has been widely used as new penetration promoter in the field of trandermial drug delivery system(TDDS) and been proved to be effective. In the first, the spectral characteristics of borneol was obtained and analyzed by Fourier Transformation Infrared (FTIR) spectrophotometer. And further experimental studies were performed to probe if borneol is capable of optical clearing of porcine skin tissue in vitro with near infrared spectroscopy, double integrating-spheres system and Inverse Adding-Doubling(IAD) algorithm. Spectral results show that light penetration depth into skin tissue got the increase. Meanwhile, absorption coefficient and scattering coefficient of porcine skin treated by borneol got the decrease during the permeation of Borneol. Therefore, Borneol could be potentially used as enhancer for tissue optical clearing to improve non-invasive light-based diagnostic and imaging techniques while practically optical application and clinical safety are under consideration.

  16. Simplified approach for quantitative calculations of optical pumping

    International Nuclear Information System (INIS)

    Atoneche, Fred; Kastberg, Anders

    2017-01-01

    We present a simple and pedagogical method for quickly calculating optical pumping processes based on linearised population rate equations. The method can easily be implemented on mathematical software run on modest personal computers, and can be generalised to any number of concrete situations. We also show that the method is still simple with realistic experimental complications taken into account, such as high level degeneracy, impure light polarisation, and an added external magnetic field. The method and the associated mathematical toolbox should be of value in advanced physics teaching, and can also facilitate the preparation of research tasks. (paper)

  17. Simplified approach for quantitative calculations of optical pumping

    Science.gov (United States)

    Atoneche, Fred; Kastberg, Anders

    2017-07-01

    We present a simple and pedagogical method for quickly calculating optical pumping processes based on linearised population rate equations. The method can easily be implemented on mathematical software run on modest personal computers, and can be generalised to any number of concrete situations. We also show that the method is still simple with realistic experimental complications taken into account, such as high level degeneracy, impure light polarisation, and an added external magnetic field. The method and the associated mathematical toolbox should be of value in advanced physics teaching, and can also facilitate the preparation of research tasks.

  18. Tourist Potential in a Sustainable Approach. An Application Case

    Directory of Open Access Journals (Sweden)

    Eddy Soria-Leyva

    2015-11-01

    Full Text Available In this research is proposed a methodology to evaluate the tourist potential with a sustainable approach and it is validated through an application in the municipality of the Tercer Frente, Santiago de Cuba. With this aim, some instruments of measure and mathematical formulas are submitted in order to obtain discriminating information about tourist resources, taking into account the delimitation of zones for the tourist development and the classification of determining factors of the tourist potential according to the capability of attraction and reception of the tourist demand, becoming adapted to the historic concrete conditions of the territory. Therefore, its application will determine a solid base for the future planning of tourist local development of this municipality. Among the main conclusions, it is deduced that Tercer Frente is a secondary semi-specialized destination which has medium tourist potential and possibilities to increase the spatial correlation among the tourist plant and the distribution of attractions in five zones.

  19. The optical potential for 6Li-6Li elastic scattering at 156 MeV

    International Nuclear Information System (INIS)

    Micek, S.; Majka, Z.; Klewe-Nebenius, H.; Rebel, H.; Gils, H.J.

    1984-10-01

    Elastic scattering of 6 Li from 6 Li has been studied for the beam energy of 156 MeV. The experimental differential cross section has been analysed on the basis of the optical model using various phenomenological forms. The spin-orbit interaction proves to be less significant. A semi-microscopic double-folding cluster model which generates the real part of the optical potential by an antisymmetrized d-α cluster wave function of 6 Li and α-α, d-d and d-α interactions is well able to describe the experimental data. (orig.) [de

  20. Temperature dependence of the in situ widths of a rotating condensate in one dimensional optical potential

    International Nuclear Information System (INIS)

    Hassan, Ahmed S.; Soliman, Shemi S.M.

    2016-01-01

    In this paper, a conventional method of quantum statistical mechanics is used to study the temperature dependence of the in situ widths of a rotating condensate bosons in 1D optical potential. We trace the experimentally accessible parameters for which the temperature dependence of the in situ widths becomes perceivable. The calculated results showed that the temperature dependence of the in situ widths is completely different from that of a rotating condensate or trapped bosons in the optical lattice separately. The z-width shows distinct behavior from x- and y-widths due to the rotation effect. The obtained results provide useful qualitative theoretical results for future Bose Einstein condensation experiments in such traps. - Highlights: • The temperature dependence of the in situ widths of a rotating condensate boson in 1D optical potential is investigated. • We trace the experimentally accessible parameters for which the in situ widths become perceivable. • The above mentioned parameters exhibit a characteristic rotation rate and optical potential depth dependence. • Characteristic dependence of the effective widths on temperature is investigated. • Our results provide useful qualitatively and quantitative theoretical results for experiments in various traps.

  1. Distorted-wave Born approximation in the case of an optical scattering potential

    International Nuclear Information System (INIS)

    Mytnichenko, Sergey V.

    2005-01-01

    Application of the distorted-wave Born approximation in the conventional form developed for the case of a real scattering potential is shown to cause significant errors in calculating X-ray diffuse scattering from non-ideal crystals, superlattices, multilayers and other objects if energy dissipation (photoabsorption, inelastic scattering, and so on) is not negligible, or in other words, in the case of an optical (complex) scattering potential. We show how a correct expression for the X-ray diffuse-scattering cross-section can be obtained in this case. Generally, the diffuse-scattering cross-section from an optical potential is not T-invariant, i.e. the reciprocity principle is violated. Violations of T-invariance are more evident when the dynamical nature of the diffraction is more critical

  2. The Optical Flow Technique on the Research of Solar Non-potentiality

    Science.gov (United States)

    Liu, Ji-hong; Zhang, Hong-qi

    2010-06-01

    Several optical flow techniques, which have being applied to the researches of solar magnetic non-potentiality recently, have been summarized here. And a few new non-potential parameters which can be derived from them have been discussed, too. The main components of the work are presented as follows: (1) The optical flow techniques refers to a series of new image analyzing techniques arisen recently on the researches of solar magnetic non-potentiality. They mainly include LCT (local correlation tracking), ILCT (inductive equation combining with LCT), MEF (minimum energy effect), DAVE (differential affine velocity estimator) and NAVE (nonlinear affine velocity estimator). Their calculating and applying conditions, merits and deficiencies, all have been discussed detailedly in this work. (2) Benefit from the optical flow techniques, the transverse velocity fields of the magnetic features on the solar surface may be determined by a time sequence of high-quality images currently produced by high-resolution observations either from the ground or in space. Consequently, several new non-potential parameters may be acquired, such as the magnetic helicity flux, the induced electric field in the photosphere, the non-potential magnetic stress (whose area integration is the Lorentz force), etc. Then we can determine the energy flux across the photosphere, and subsequently evaluate the energy budget. Former works on them by small or special samples have shown that they are probably related closely to the erupting events, such as flare, filament eruptions and coronal mass ejections.

  3. Capacity-Approaching Superposition Coding for Optical Fiber Links

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Zibar, Darko; Tafur Monroy, Idelfonso

    2014-01-01

    We report on the first experimental demonstration of superposition coded modulation (SCM) for polarization-multiplexed coherent-detection optical fiber links. The proposed coded modulation scheme is combined with phase-shifted bit-to-symbol mapping (PSM) in order to achieve geometric and passive......-SCM) is employed in the framework of bit-interleaved coded modulation with iterative decoding (BICM-ID) for forward error correction. The fiber transmission system is characterized in terms of signal-to-noise ratio for back-to-back case and correlated with simulated results for ideal transmission over additive...... white Gaussian noise channel. Thereafter, successful demodulation and decoding after dispersion-unmanaged transmission over 240-km standard single mode fiber of dual-polarization 6-Gbaud 16-, 32- and 64-ary SCM-PSM is experimentally demonstrated....

  4. Advanced free space optics (FSO) a systems approach

    CERN Document Server

    Majumdar, Arun K

    2015-01-01

    This book provides a comprehensive, unified tutorial covering the most recent advances in the technology of free-space optics (FSO). It is an all-inclusive source of information on the fundamentals of FSO as well as up-to-date information on the state-of-the-art in technologies available today. This text is intended for graduate students, and will also be useful for research scientists and engineers with an interest in the field. FSO communication is a practical solution for creating a three dimensional global broadband communications grid, offering bandwidths far beyond what is possible in the Radio Frequency (RF) range. However, the attributes of atmospheric turbulence and scattering impose perennial limitations on availability and reliability of FSO links. From a systems point-of-view, this groundbreaking book provides a thorough understanding of channel behavior, which can be used to design and evaluate optimum transmission techniques that operate under realistic atmospheric conditions. Topics addressed...

  5. Microscopic optical potential calculations of finite nuclei with extended skyrme forces

    International Nuclear Information System (INIS)

    Yuan Haiji; Ye Weilei; Gao Qin; Shen Qingbiao

    1986-01-01

    Microscopic optical potential calculations in the Hartree-Fock (HF) approximation with Extended Skyrme forces are investigated. The HF equation is derived from the variation principle and the potential formula of spherical nuclei is obtained by two different ways. Then the calculations for symmetrid nuclei 16 O, 40 Ca and asymmetric nucleus 90 Zr with eight sets of Skyrme force parameters are presented. Our results show that the potential form and variating tendency with incident energy are reasonable and there apparently appears a 'wine-bottle-bottom' shape in the intermediate energy region. Furthermore, our calculations reflect shell effects clearly

  6. Generalized approach to modifying optical vortices with suppressed sidelobes using Bessel-like functions.

    Science.gov (United States)

    Chen, J; Yuan, X-C; Zhao, X; Fang, Z L; Zhu, S W

    2009-11-01

    We propose a generalized approach to producing optical vortices with suppressed sidelobes using a variable Bessel-like function added to the conventional spiral phase plate. Experimental verifications are implemented by a phase-only spatial light modulator. It is demonstrated that the method is valid for optical vortex beams with arbitrary topological charges and without changing the primary ring size as a unique property among the existing techniques.

  7. Calculation of real optical model potential for heavy ions in the framework of the folding model

    International Nuclear Information System (INIS)

    Goncharov, S.A.; Timofeyuk, N.K.; Kazacha, G.S.

    1987-01-01

    The code for calculation of a real optical model potential in the framework of the folding model is realized. The program of numerical Fourier-Bessel transformation based on Filon's integration rule is used. The accuracy of numerical calculations is ∼ 10 -4 for a distance interval up to a bout (2.5-3) times the size of nuclei. The potentials are calculated for interactions of 3,4 He with nuclei from 9 Be to 27 Al with different effective NN-interactions and densities obtained from electron scattering data. Calculated potentials are similar to phenomenological potentials in Woods-Saxon form. With calculated potentials the available elastic scattering data for the considered nuclei in the energy interval 18-56 MeV are analysed. The needed renormalizations for folding potentials are < or approx. 20%

  8. Isobar contributions to the imaginary part of the optical-model potential for finite nuclei

    International Nuclear Information System (INIS)

    Hjort-Jensen, M.; Borromeo, M.; Muether, H.; Polls, A.

    1992-03-01

    A recently developed non-relativistic method for calculating the nucleon optical-model potential has been employed to evaluate the contributions from isobaric degrees of freedom to the imaginary part of the nucleon optical-model potential. To evaluate the imaginary part of the optical-model potential, the authors include the contributions from terms to second order in the Brueckner G-matrix with and without the inclusion of isobars Δ. Results for 16 O are presented in this work. The contributions to the imaginary part are given by the two-particle-one-hole (2p1h) and three-particle-two-hole (3p2h) diagrams. The latter contributes at negative energies only and the contribution from isobar intermediate states is rather small. The 2p1h receives significant contributions from isobars at energies near the resonance and above the threshold for the excitation of ΔΔ states. In particular, the importance of ΔΔ configurations is rather sensitive to the treatment of short-range correlations. The parameterization of the self-energy in terms of local potentials is discussed. The depletion of the occupation of the single-particle orbits due to nucleon-nucleon correlations and Δ excitations is evaluated. 49 refs., 14 figs., 3 tabs

  9. Optical potentials derived from microscopic separable interactions including binding and recoil effects

    International Nuclear Information System (INIS)

    Siciliano, E.R.; Walker, G.E.

    1976-01-01

    We first consider a projectile scattering from a nucleon bound in a fixed potential. A separable Galilean invariant projectile-nucleon interaction is adopted. Without using the fixed scatterer approximation or using closure on the intermediate target nucleon states we obtain various forms for the projectile-bound nucleon t matrix. Effects due to intermediate target excitation and nucleon recoil are discussed. By making the further approximations of closure and fixed scatterers we make connection with the work of previous authors. By generalizing to projectile interaction with several bound nucleons and examining the appropriate multiple scattering series we identify the optical potential for projectile elastic scattering from the many-body system. Different optical potentials are obtained for different projectile-bound nucleon t matrices, and we study the differences predicted by these dissimilar optical potentials for elastic scattering. In a model problem, we study pion-nucleus elastic scattering and compare the predictions obtained by adopting procedures used by (1) Landau, Phatak, and Tabakin and (2) Piepho-Walker to the predictions obtained in a less restrictive, but computationally difficult treatment

  10. High-resolution imaging of ultracold fermions in microscopically tailored optical potentials

    International Nuclear Information System (INIS)

    Zimmermann, B; Mueller, T; Meineke, J; Esslinger, T; Moritz, H

    2011-01-01

    We report on the local probing and preparation of an ultracold Fermi gas on the length scale of one micrometer, i.e. of the order of the Fermi wavelength. The essential tool of our experimental setup is a pair of identical, high-resolution microscope objectives. One of the microscope objectives allows local imaging of the trapped Fermi gas of 6 Li atoms with a maximum resolution of 660 nm, while the other enables the generation of arbitrary optical dipole potentials on the same length scale. Employing a two-dimensional (2D) acousto-optical deflector, we demonstrate the formation of several trapping geometries, including a tightly focused single optical dipole trap, a 4x4 site 2D optical lattice and an 8 site ring lattice configuration. Furthermore, we show the ability to load and detect a small number of atoms in these trapping potentials. A site separation down to one micrometer in combination with the low mass of 6 Li results in tunneling rates that are sufficiently large for the implementation of Hubbard models with the designed geometries.

  11. Molecular Architectural Approach to Novel Electro-Optical Materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.; Johal, M.S.; Smilowitz, L.B.; Robinson, J.M.

    1999-06-29

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The goal is to construct polar multilayers with nonlinear optical coefficients larger than classical inorganic crystals such as KDP or quartz. The strategy is to use various chemical interactions such as covalent bonds or hydrogen bonding to build polar structures. We have synthesized novel barbituric acid and melamine derivatives that will spontaneously self-assemble into a supramolecular ribbon according to their complementary H-bond motif. This supramolecular ribbon can then stack into a polar multilayer structure as verified by sum frequency generation (w{sub 1}+w{sub 2}) or second harmonic generation (when w{sub 1}=w{sub 2}). Second harmonic generation yields a value of d{sub 33}=3.2 pm/V for the self-assembled films and sum frequency generation shows a net polar orientation of the methyl groups in the multilayer along the surface normal. X-ray diffraction confirms the layered structure and produces the periodicity of {approximately}41 A, which corresponds well to the width of the supramolecular ribbons ({approximately}40 A).

  12. Thermo-optic characteristics of hybrid polymer/silica microstructured optical fiber: An analytical approach

    Science.gov (United States)

    Sharma, Dinesh Kumar; Sharma, Anurag; Tripathi, Saurabh Mani

    2018-04-01

    Microstructured optical fibers (MOFs) allow a variety of advanced materials to be infiltrated in their air-voids for obtaining the increased fiber functionality, and offering a new versatile platform for developing the compact sensors devices. We aim to investigate the thermal characteristics of high-index core triangular hybrid polymer/silica MOFs with circular air-voids infused with polymer by using the analytical field model [1]. We demonstrate that infiltration of air-voids with polymer, e.g., polydimethylsiloxane (PDMS) can facilitate to tune the fundamental modal properties of MOF such as effective index of the mode, near and the far-field profiles, effective mode area and the numerical aperture over the temperature ranging from 0 °C to 100 °C, for different values of relative air-void ratios. The evolution of the mode shape for a given temperature has been investigated in transition from near-field to far-field regime. We have studied the thermal dependence of splice losses between hybrid MOF and the standard step-index single-mode optical fiber in combination with Fresnel losses. For enhancing the evanescent field interactions, we have evaluated fraction of power associated with fundamental mode of hybrid MOF. We have compared the accuracy of our results with those based on full-vector finite-difference (FD) method, as available in the literature.

  13. Energy-dependent microscopic optical potential for scattering of nucleons on light nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Farag, M.Y.H.; Esmael, E.H. [Cairo University, Physics Department, Faculty of Science, Giza (Egypt); Maridi, H.M. [Cairo University, Physics Department, Faculty of Science, Giza (Egypt); Taiz University, Physics Department, Faculty of Applied Science, Taiz (Yemen)

    2014-06-15

    We present an energy-dependent microscopic optical model potential for elastic scattering of nucleons on light nuclei. The single-folding model is used for the real part of the optical potential (OP), while the imaginary part is derived within the high-energy approximation theory. The energy dependence of the OP is determined from the parameterization of the volume integrals those calculated from the best-fit OP that fit the experimental data of the cross sections and analyzing powers. This energy-dependent OP is successfully applied to analyze the proton elastic scattering of {sup 4,6,i8}He, {sup 6,7}Li, and {sup 9,10}Be nuclei at low and intermediate incident energies up to 200MeV/nucleon. (orig.)

  14. Experimental study of neutron-optical potential with absorption using Fabry-Perot magnetic resonator

    International Nuclear Information System (INIS)

    Hino, M.; Tasaki, S.; Ebisawa, T.; Kawai, T.; Achiwa, N.; Yamazaki, D.

    1999-01-01

    Complete text of publication follows. Recently spin precession angles of neutrons tunneling and non-tunneling through [Permalloy45(PA)-germanium(Ge)]-PA Fabry-Perot magnetic resonator have been observed [1]. The spin precession angle is well reproduced by the theoretical phase difference of up and down spin neutron wave function based on one-dimensional Schroedinger equation using optical potential model [2]. Spin precession angle and transmission probability of neutron through PA-(Ge/Gd)-PA Fabry-Perot magnetic resonator are presented, where the gap(Ge/Gd) layer consists of germanium and gadolinium atoms, and the optical potential model for magnetic multilayer system with absorption is discussed. (author) [1] M. Hino, et al., Physica B 241-243, 1083 (1998).; [2] S. Yamada, et al., Annu. Rep. Res. Reactor Inst. Kyoto Univ. 11, 8 (1978)

  15. A Realization of a Quasi-Random Walk for Atoms in Time-Dependent Optical Potentials

    Directory of Open Access Journals (Sweden)

    Torsten Hinkel

    2015-09-01

    Full Text Available We consider the time dependent dynamics of an atom in a two-color pumped cavity, longitudinally through a side mirror and transversally via direct driving of the atomic dipole. The beating of the two driving frequencies leads to a time dependent effective optical potential that forces the atom into a non-trivial motion, strongly resembling a discrete random walk behavior between lattice sites. We provide both numerical and analytical analysis of such a quasi-random walk behavior.

  16. Contribution to the study of the optical potentials used at low energy for heavy ions

    International Nuclear Information System (INIS)

    Goncalves, Nadine.

    1980-12-01

    The object of this work is essentially to determine optical potentials by simultaneous analysis of elastic and inelastic scattering. The theoretical concepts required for analyzing experimental results are introduced, then the optical model, the coupled equation as well as the double convolution potential are presented. The transfer of a nucleon will be studied by Born's approximation of distorted waves if the process is direct and in one single stage. But if the process occurs in two stages, it is Born's approximation of coupled paths that enables the inelastic collective excitations to be taken into account. The two stage process plays a significant part in peopling the highly collective states of the residual nucleus. The experimental techniques employed in order to obtain angular distributions are dealt with in Chapter III. Three types of different detections were utilized: a semi-conducting junction, a Buechner analysis magnet, then a magnetic spectrometer composed of a quadripole and three dipoles in succession, so as to better the energy resolutions. The analysis of the experimental results is divided into two chapters, chapters IV and V. The first is devoted to the heavier systems, namely the pair-pair isotopes of Ge and Ni, and deals exclusively with the problem of determining optical potentials and its ambiguities. The second one deals with the lighter systems relative to 28 Si. On the one hand, it aims to study the elastic and inelastic angular distributions at the intermediate angles with 16 O and 18 O ions and, on the other hand, to make use of the optical potentials in the study of the transfer of a nucleon, to wit the pick-up of a 28 Si( 15 N, 16 O) 27 Al proton and the stripping of a 28 Si( 15 N, 14 N) 29 Si neutron [fr

  17. Localization of Matter Waves in Two-Dimensional Disordered Optical Potentials

    International Nuclear Information System (INIS)

    Kuhn, R.C.; Miniatura, C.; Delande, D.; Sigwarth, O.; Mueller, C.A.

    2005-01-01

    We consider ultracold atoms in 2D disordered optical potentials and calculate microscopic quantities characterizing matter wave quantum transport in the noninteracting regime. We derive the diffusion constant as a function of all relevant microscopic parameters and show that coherent multiple scattering induces significant weak localization effects. In particular, we find that even the strong localization regime is accessible with current experimental techniques and calculate the corresponding localization length

  18. Cholinergic Potentiation of Restoration of Visual Function after Optic Nerve Damage in Rats

    Directory of Open Access Journals (Sweden)

    Mira Chamoun

    2017-01-01

    Full Text Available Enhancing cortical plasticity and brain connectivity may improve residual vision following a visual impairment. Since acetylcholine plays an important role in attention and neuronal plasticity, we explored whether potentiation of the cholinergic transmission has an effect on the visual function restoration. To this end, we evaluated for 4 weeks the effect of the acetylcholinesterase inhibitor donepezil on brightness discrimination, visually evoked potentials, and visual cortex reactivity after a bilateral and partial optic nerve crush in adult rats. Donepezil administration enhanced brightness discrimination capacity after optic nerve crush compared to nontreated animals. The visually evoked activation of the primary visual cortex was not restored, as measured by evoked potentials, but the cortical neuronal activity measured by thallium autometallography was not significantly affected four weeks after the optic nerve crush. Altogether, the results suggest a role of the cholinergic system in postlesion cortical plasticity. This finding agrees with the view that restoration of visual function may involve mechanisms beyond the area of primary damage and opens a new perspective for improving visual rehabilitation in humans.

  19. Effect of imaginary part of an optical potential on reaction total cross sections

    International Nuclear Information System (INIS)

    Afanas'ev, G.N.; Dobromyslov, M.B.; Kim Yng Pkhung; Shilov, V.M.

    1977-01-01

    The effect of the imaginary part of optical potential on the total cross sections of reactions is explained. The complex rectangular well model is used, i.e. the real rectangular well at r 16 O + 27 Al reactions and the partial permeabilities are presented. It is demonstrated that the S-matrix has proved to be unitary. Oscillations of the partial permeabilities and cross-sections are observed for small potential values in the Wsub(o) imaginary part, which no longer occur at larger Wsub(o). This corresponds to the overlapping and nonoverlapping quasistationary levels in complex rectangular well

  20. Influence of trapping potentials on the phase diagram of bosonic atoms in optical lattices

    International Nuclear Information System (INIS)

    Giampaolo, S.M.; Illuminati, F.; Mazzarella, G.; De Siena, S.

    2004-01-01

    We study the effect of external trapping potentials on the phase diagram of bosonic atoms in optical lattices. We introduce a generalized Bose-Hubbard Hamiltonian that includes the structure of the energy levels of the trapping potential, and show that these levels are in general populated both at finite and zero temperature. We characterize the properties of the superfluid transition for this situation and compare them with those of the standard Bose-Hubbard description. We briefly discuss similar behaviors for fermionic systems

  1. On the imaginary part of the S-wave pion-nucleus optical potential

    International Nuclear Information System (INIS)

    Germond, J.F.; Lombard, R.J.

    1991-01-01

    The contribution of pion absorption to the imaginary part of the S-wave pion-nucleus optical potential is calculated with Slater determinantal antisymmetrized nuclear wave funtions, taking fully into accout the spin and isospin degrees of freedom. The potential obtained has an explicit dependence on the proton and neutron nuclear densities whose coefficients are directly related to the two-nucleon absorption coupling constants. The values of these coefficients extracted from mesic atoms data are in good agreement with those deduced from exclusive pion absorption experiments in 3 He, but larger than the predictions of the pion rescattering model. (orig.)

  2. Event-related potentials, cognition, and behavior: a biological approach.

    Science.gov (United States)

    Kotchoubey, Boris

    2006-01-01

    The prevailing cognitive-psychological accounts of event-related brain potentials (ERPs) assume that ERP components manifest information processing operations leading from stimulus to response. Since this view encounters numerous difficulties already analyzed in previous studies, an alternative view is presented here that regards cortical control of behavior as a repetitive sensorimotor cycle consisting of two phases: (i) feedforward anticipation and (ii) feedback cortical performance. This view allows us to interpret in an integrative manner numerous data obtained from very different domains of ERP studies: from biophysics of ERP waves to their relationship to the processing of language, in which verbal behavior is viewed as likewise controlled by the same two basic control processes: feedforward (hypothesis building) and feedback (hypothesis checking). The proposed approach is intentionally simplified, explaining numerous effects on the basis of few assumptions and relating several levels of analysis: neurophysiology, macroelectrical processes (i.e. ERPs), cognition and behavior. It can, therefore, be regarded as a first approximation to a general theory of ERPs.

  3. Development of Optically Active Nanostructures for Potential Applications in Sensing, Therapeutics and Imaging

    Science.gov (United States)

    Joshi, Padmanabh

    Materials at nanoscale are finding manifold applications in the various fields like sensing, plasmonics, therapeutics, to mention a few. Large amount of development has taken place regarding synthesis and exploring the novel applications of the various types of nanomaterials like organic, inorganic and hybrid of both. Yet, it is believed that the full potential of different nanomaterials is yet to be fully established stimulating researchers to explore more in the field of nanotechnology. Building on the same premise, in the following studies we have developed the nanomaterials in the class of optically active nanoparticles. First part of the study we have successfully designed, synthesized, and characterized Ag-Fe3O4 nanocomposite substrate for potential applications in quantitative Surface Enhanced Raman Scattering (SERS) measurements. Quantitative SERS-based detection of dopamine was performed successfully. In subsequent study, facile, single-step synthesis of polyethyleneimine (PEI) coated lanthanide based NaYF4 (Yb, Er) nanoparticles was developed and their application as potential photodynamic therapy agent was studied using excitations by light in near infra-red and visible region. In the following and last study, synthesis and characterization of the conjugated polymer nanoparticles was attempted successfully. Functionalization of the conjugated nanoparticles, which is a bottleneck for their potential applications, was successfully performed by encapsulating them in the silica nanoparticles, surface of which was then functionalized by amine group. Three types of optically active nanoparticles were developed for potential applications in sensing, therapeutics and imaging.

  4. High-precision optical systems with inexpensive hardware: a unified alignment and structural design approach

    Science.gov (United States)

    Winrow, Edward G.; Chavez, Victor H.

    2011-09-01

    High-precision opto-mechanical structures have historically been plagued by high costs for both hardware and the associated alignment and assembly process. This problem is especially true for space applications where only a few production units are produced. A methodology for optical alignment and optical structure design is presented which shifts the mechanism of maintaining precision from tightly toleranced, machined flight hardware to reusable, modular tooling. Using the proposed methodology, optical alignment error sources are reduced by the direct alignment of optics through their surface retroreflections (pips) as seen through a theodolite. Optical alignment adjustments are actualized through motorized, sub-micron precision actuators in 5 degrees of freedom. Optical structure hardware costs are reduced through the use of simple shapes (tubes, plates) and repeated components. This approach produces significantly cheaper hardware and more efficient assembly without sacrificing alignment precision or optical structure stability. The design, alignment plan and assembly of a 4" aperture, carbon fiber composite, Schmidt-Cassegrain concept telescope is presented.

  5. Calculations of nucleus-nucleus microscopic optical potentials at intermediate energies

    International Nuclear Information System (INIS)

    Hanna, K.M.; Kuhtina, I.N.; Lukyanov, K.V.; Lukyanov, V.K.; Zemlyanaya, E.V.; Slowinski, B.

    2006-01-01

    Three types of microscopic nucleus-nucleus optical potentials are constructed using three patterns for their real and imaginary parts. Two of these patterns are the real V H and imaginary W H parts of the potential which reproduces the high-energy amplitude of scattering in the microscopic Glauber-Sitenko theory. Another template VDF is calculated within the standard double-folding model with the exchange term included. For either of the three tested potentials, the contribution of real and imaginary patterns is adjusted by introducing two fitted factors. Correspondingly, using numerical code ECIS, the elastic differential cross-sections were fitted to the experimental data on scattering of the 16,17 O heavy-ions at about hundred Mev/nucleon on various target-nuclei. The relativization effect is also included. The tables of the obtained factors which renormalize the strengths of the real and (or) imaginary parts of the calculated microscopic potentials are given

  6. Noise study of all-normal dispersion supercontinuum sources for potential application in optical coherence tomography

    DEFF Research Database (Denmark)

    Bravo Gonzalo, Ivan; Engelsholm, Rasmus Dybbro; Bang, Ole

    2017-01-01

    bandwidths, such sources are characterized by large intensity fluctuations, limiting their performance for applications in imaging such as optical coherence tomography (OCT). An approach to eliminate the influence of noise sensitive effects is to use a so-called all-normal dispersion (ANDi) fiber, in which...... the dispersion is normal for all the wavelengths of interest. Pumping these types of fibers with short enough femtosecond pulses allows to suppress stimulated Raman scattering (SRS), which is known to be as noisy process as modulation instability (MI), and coherent SC is generated through self-phase modulation...... (SPM) and optical wave breaking (OWB). In this study, we show the importance of the pump laser and fiber parameters in the design of low-noise ANDi based SC sources, for application in OCT. We numerically investigate the pulse-to-pulse fluctuations of the SC, calculating the relative intensity noise...

  7. Contrast improvement of continuous wave diffuse optical tomography reconstruction by hybrid approach using least square and genetic algorithm

    Science.gov (United States)

    Patra, Rusha; Dutta, Pranab K.

    2015-07-01

    Reconstruction of the absorption coefficient of tissue with good contrast is of key importance in functional diffuse optical imaging. A hybrid approach using model-based iterative image reconstruction and a genetic algorithm is proposed to enhance the contrast of the reconstructed image. The proposed method yields an observed contrast of 98.4%, mean square error of 0.638×10-3, and object centroid error of (0.001 to 0.22) mm. Experimental validation of the proposed method has also been provided with tissue-like phantoms which shows a significant improvement in image quality and thus establishes the potential of the method for functional diffuse optical tomography reconstruction with continuous wave setup. A case study of finger joint imaging is illustrated as well to show the prospect of the proposed method in clinical diagnosis. The method can also be applied to the concentration measurement of a region of interest in a turbid medium.

  8. Surgical approach and optic coherence tomographic evaluation of optic disc anomaly in association with serous macular detachment.

    Science.gov (United States)

    Güven, Dilek; Balcıoğlu, Nihal; Türker, Cağrı; Baydar, Yasemin; Sendül, Yekta

    2013-12-01

    Serous macular detachment (SMD) may accompany optic disc pit (ODP) and cause visual loss if untreated. We want to present different therapeutic approaches and interesting optical coherence tomography (OCT) findings in three consecutive cases. In this case series, two patients with SMD and one patient with partial macular detachment and inferior retinal detachment accompanying ODP were evaluated before and after surgical intervention clinically and by spectral-domain OCT. The patients were 44 (case 1), 22 (case 2) and 24 (case 3) years old. Pars plana vitrectomy (PPV) + silicone oil + laser, PPV + sulfur hexafluoride gas (SF6) + laser and pneumatic retinopexy were applied, respectively. The patients were followed for 18, 15 and 14 months. Preoperative best-corrected visual acuities (BCVAs) were 5/100, 7/10 and counting fingers at 1 m. Vision improved in all cases with resolution of subretinal fluid. Final BCVAs were 3/10, 10/10 and 1/10, respectively. OCT images revealed optic disc anomaly details and changes after surgical intervention, photoreceptor outer segment alterations at the detached area and macular surface changes. Surgical intervention should be tailored individually in cases with SMD. OCT is efficient for in vivo evaluation of this pathological condition and anatomical outcomes of surgery.

  9. A Method to Analyze the Potential of Optical Remote Sensing for Benthic Habitat Mapping

    Directory of Open Access Journals (Sweden)

    Rodrigo A. Garcia

    2015-10-01

    Full Text Available Quantifying the number and type of benthic classes that are able to be spectrally identified in shallow water remote sensing is important in understanding its potential for habitat mapping. Factors that impact the effectiveness of shallow water habitat mapping include water column turbidity, depth, sensor and environmental noise, spectral resolution of the sensor and spectral variability of the benthic classes. In this paper, we present a simple hierarchical clustering method coupled with a shallow water forward model to generate water-column specific spectral libraries. This technique requires no prior decision on the number of classes to output: the resultant classes are optically separable above the spectral noise introduced by the sensor, image based radiometric corrections, the benthos’ natural spectral variability and the attenuating properties of a variable water column at depth. The modeling reveals the effect reducing the spectral resolution has on the number and type of classes that are optically distinct. We illustrate the potential of this clustering algorithm in an analysis of the conditions, including clustering accuracy, sensor spectral resolution and water column optical properties and depth that enabled the spectral distinction of the seagrass Amphibolis antartica from benthic algae.

  10. Synthesis and characterization of silver nanoparticles from Alpinia calcarata by Green approach and its applications in bactericidal and nonlinear optics

    Energy Technology Data Exchange (ETDEWEB)

    Pugazhendhi, S.; Kirubha, E. [Department of Physics, Anna University, Chennai 600 025 (India); Palanisamy, P.K. [Department of Medical Physics, Anna University, Chennai 600 025 (India); Gopalakrishnan, R., E-mail: krgkrishnan@yahoo.com [Department of Physics, Anna University, Chennai 600 025 (India)

    2015-12-01

    Graphical abstract: - Highlights: • Alpinia calcarata root extract was used for the synthesis Ag nanoparticle. • AgNPs show remarkable stability at 25–30 °C. • The morphologies of the AgNPs were analyzed using HRTEM. • AgNPs exhibit good nonlinear optical behaviour and antimicrobial activities. - Abstract: Development of green route for the synthesis of nanoparticles with plant extracts plays a very important role in nanotechnology without any toxicity chemicals. Herein we report a new approach to synthesize silver nanoparticles (AgNPs) using aqueous extract of Alpinia calcarata root as a reducing as well as stabilizing agent. The crystal structure and purity of the synthesized AgNPs were studied using Powder X-ray Diffraction analysis. The Surface Plasmon Resonance bands of synthesized silver nanoparticles have been obtained and monitored using UV–Visible spectrum. The morphologies of the AgNPs were analyzed using High resolution transmission electron microscopy (HRTEM). The elements present in the A. calcarata extract were determined by the inductively coupled plasma-optical emission Spectrometry (ICP-OES) and Fourier transform infrared spectroscopy (FTIR). Silver nanoparticles from A. calcarata possess very good antimicrobial activity which was confirmed by resazurin dye reduction assay method and thus it is a potential source of antimicrobial agent. The synthesized Ag nanoparticles exhibit good optical nonlinearity and the nonlinear optical studies have been carried out by Z-scan technique.

  11. Synthesis and characterization of silver nanoparticles from Alpinia calcarata by Green approach and its applications in bactericidal and nonlinear optics

    International Nuclear Information System (INIS)

    Pugazhendhi, S.; Kirubha, E.; Palanisamy, P.K.; Gopalakrishnan, R.

    2015-01-01

    Graphical abstract: - Highlights: • Alpinia calcarata root extract was used for the synthesis Ag nanoparticle. • AgNPs show remarkable stability at 25–30 °C. • The morphologies of the AgNPs were analyzed using HRTEM. • AgNPs exhibit good nonlinear optical behaviour and antimicrobial activities. - Abstract: Development of green route for the synthesis of nanoparticles with plant extracts plays a very important role in nanotechnology without any toxicity chemicals. Herein we report a new approach to synthesize silver nanoparticles (AgNPs) using aqueous extract of Alpinia calcarata root as a reducing as well as stabilizing agent. The crystal structure and purity of the synthesized AgNPs were studied using Powder X-ray Diffraction analysis. The Surface Plasmon Resonance bands of synthesized silver nanoparticles have been obtained and monitored using UV–Visible spectrum. The morphologies of the AgNPs were analyzed using High resolution transmission electron microscopy (HRTEM). The elements present in the A. calcarata extract were determined by the inductively coupled plasma-optical emission Spectrometry (ICP-OES) and Fourier transform infrared spectroscopy (FTIR). Silver nanoparticles from A. calcarata possess very good antimicrobial activity which was confirmed by resazurin dye reduction assay method and thus it is a potential source of antimicrobial agent. The synthesized Ag nanoparticles exhibit good optical nonlinearity and the nonlinear optical studies have been carried out by Z-scan technique.

  12. Time-variable gravity potential components for optical clock comparisons and the definition of international time scales

    International Nuclear Information System (INIS)

    Voigt, C.; Denker, H.; Timmen, L.

    2016-01-01

    The latest generation of optical atomic clocks is approaching the level of one part in 10 18 in terms of frequency stability and uncertainty. For clock comparisons and the definition of international time scales, a relativistic redshift effect of the clock frequencies has to be taken into account at a corresponding uncertainty level of about 0.1 m 2 s -2 and 0.01 m in terms of gravity potential and height, respectively. Besides the predominant static part of the gravity potential, temporal variations must be considered in order to avoid systematic frequency shifts. Time-variable gravity potential components induced by tides and non-tidal mass redistributions are investigated with regard to the level of one part in 10 18 . The magnitudes and dominant time periods of the individual gravity potential contributions are investigated globally and for specific laboratory sites together with the related uncertainty estimates. The basics of the computation methods are presented along with the applied models, data sets and software. Solid Earth tides contribute by far the most dominant signal with a global maximum amplitude of 4.2 m 2 s -2 for the potential and a range (maximum-to-minimum) of up to 1.3 and 10.0 m 2 s -2 in terms of potential differences between specific laboratories over continental and intercontinental scales, respectively. Amplitudes of the ocean tidal loading potential can amount up to 1.25 m 2 s -2 , while the range of the potential between specific laboratories is 0.3 and 1.1 m 2 s -2 over continental and intercontinental scales, respectively. These are the only two contributors being relevant at a 10 -17 level. However, several other time-variable potential effects can particularly affect clock comparisons at the 10 -18 level. Besides solid Earth pole tides, these are non-tidal mass redistributions in the atmosphere, the oceans and the continental water storage. (authors)

  13. An empirical InSAR-optical fusion approach to mapping vegetation canopy height

    Science.gov (United States)

    Wayne S. Walker; Josef M. Kellndorfer; Elizabeth LaPoint; Michael Hoppus; James Westfall

    2007-01-01

    Exploiting synergies afforded by a host of recently available national-scale data sets derived from interferometric synthetic aperture radar (InSAR) and passive optical remote sensing, this paper describes the development of a novel empirical approach for the provision of regional- to continental-scale estimates of vegetation canopy height. Supported by data from the...

  14. Optics

    CERN Document Server

    Mathieu, Jean Paul

    1975-01-01

    Optics, Parts 1 and 2 covers electromagnetic optics and quantum optics. The first part of the book examines the various of the important properties common to all electromagnetic radiation. This part also studies electromagnetic waves; electromagnetic optics of transparent isotropic and anisotropic media; diffraction; and two-wave and multi-wave interference. The polarization states of light, the velocity of light, and the special theory of relativity are also examined in this part. The second part is devoted to quantum optics, specifically discussing the classical molecular theory of optical p

  15. Contrasting optical properties of surface waters across the Fram Strait and its potential biological implications

    DEFF Research Database (Denmark)

    Pavlov, Alexey K.; Granskog, Mats A.; Stedmon, Colin A.

    2015-01-01

    radiation (PAR, 400-700nm), but does result in notable differences in ultraviolet (UV) light penetration, with higher attenuation in the EGC. Future changes in the Arctic Ocean system will likely affect EGC through diminishing sea-ice cover and potentially increasing CDOM export due to increase in river......Underwater light regime is controlled by distribution and optical properties of colored dissolved organic matter (CDOM) and particulate matter. The Fram Strait is a region where two contrasting water masses are found. Polar water in the East Greenland Current (EGC) and Atlantic water in the West...... Spitsbergen Current (WSC) differ with regards to temperature, salinity and optical properties. We present data on absorption properties of CDOM and particles across the Fram Strait (along 79° N), comparing Polar and Atlantic surface waters in September 2009 and 2010. CDOM absorption of Polar water in the EGC...

  16. Resonating rays in ion-ion scattering from an optical potential

    International Nuclear Information System (INIS)

    Farhan, A.R.; Stoyanov, B.J.; Nagl, A.; Uberall, H.; de Llano, M.

    1986-01-01

    The amplitude of ion-ion scattering, described, e.g., by an optical potential, separates into a ''surface-wave'' part (which, as shown before, may give rise to resonances) and a ''geometrical-ray'' part. The amplitude as alternately expressed here by the Wentzel-Kramers-Brillouin approximation resolves into an externally reflected ''barrier wave'' and into ''internal'' or ''penetrating rays'' that undergo an internal reflection together with possible additional multiple reflections. Our numerical calculations show that resonances also occur in the penetrating rays, which take place when a characteristic equation is satisfied. The geometrical meaning of the latter is determined by the optical path length of penetration being an integer multiple of π, plus a 1/2π caustic phase jump, and an extra phase shift due to barrier penetration

  17. Practice-oriented optical thin film growth simulation via multiple scale approach

    Energy Technology Data Exchange (ETDEWEB)

    Turowski, Marcus, E-mail: m.turowski@lzh.de [Laser Zentrum Hannover e.V., Hollerithallee 8, Hannover 30419 (Germany); Jupé, Marco [Laser Zentrum Hannover e.V., Hollerithallee 8, Hannover 30419 (Germany); QUEST: Centre of Quantum Engineering and Space-Time Research, Leibniz Universität Hannover (Germany); Melzig, Thomas [Fraunhofer Institute for Surface Engineering and Thin Films IST, Bienroder Weg 54e, Braunschweig 30108 (Germany); Moskovkin, Pavel [Research Centre for Physics of Matter and Radiation (PMR-LARN), University of Namur (FUNDP), 61 rue de Bruxelles, Namur 5000 (Belgium); Daniel, Alain [Centre for Research in Metallurgy, CRM, 21 Avenue du bois Saint Jean, Liège 4000 (Belgium); Pflug, Andreas [Fraunhofer Institute for Surface Engineering and Thin Films IST, Bienroder Weg 54e, Braunschweig 30108 (Germany); Lucas, Stéphane [Research Centre for Physics of Matter and Radiation (PMR-LARN), University of Namur (FUNDP), 61 rue de Bruxelles, Namur 5000 (Belgium); Ristau, Detlev [Laser Zentrum Hannover e.V., Hollerithallee 8, Hannover 30419 (Germany); QUEST: Centre of Quantum Engineering and Space-Time Research, Leibniz Universität Hannover (Germany)

    2015-10-01

    Simulation of the coating process is a very promising approach for the understanding of thin film formation. Nevertheless, this complex matter cannot be covered by a single simulation technique. To consider all mechanisms and processes influencing the optical properties of the growing thin films, various common theoretical methods have been combined to a multi-scale model approach. The simulation techniques have been selected in order to describe all processes in the coating chamber, especially the various mechanisms of thin film growth, and to enable the analysis of the resulting structural as well as optical and electronic layer properties. All methods are merged with adapted communication interfaces to achieve optimum compatibility of the different approaches and to generate physically meaningful results. The present contribution offers an approach for the full simulation of an Ion Beam Sputtering (IBS) coating process combining direct simulation Monte Carlo, classical molecular dynamics, kinetic Monte Carlo, and density functional theory. The simulation is performed exemplary for an existing IBS-coating plant to achieve a validation of the developed multi-scale approach. Finally, the modeled results are compared to experimental data. - Highlights: • A model approach for simulating an Ion Beam Sputtering (IBS) process is presented. • In order to combine the different techniques, optimized interfaces are developed. • The transport of atomic species in the coating chamber is calculated. • We modeled structural and optical film properties based on simulated IBS parameter. • The modeled and the experimental refractive index data fit very well.

  18. Optical Spectroscopy Approach for the Predictive Assessment of Kidney Functional Recovery Following Ischemic Injury

    Energy Technology Data Exchange (ETDEWEB)

    Raman, R N; Pivetti, C D; Rubenchik, A M; Matthews, D L; Troppmann, C; Demos, S G

    2010-02-11

    Tissue that has undergone significant yet unknown amount of ischemic injury is frequently encountered in organ transplantation and trauma clinics. With no reliable real-time method of assessing the degree of injury incurred in tissue, surgeons generally rely on visual observation which is subjective. In this work, we investigate the use of optical spectroscopy methods as a potentially more reliable approach. Previous work by various groups was strongly suggestive that tissue autofluorescence from NADH obtained under UV excitation is sensitive to metabolic response changes. To test and expand upon this concept, we monitored autofluorescence and light scattering intensities of injured vs. uninjured rat kidneys via multimodal imaging under 355 nm, 325 nm, and 266 nm excitation as well as scattering under 500 nm illumination. 355 nm excitation was used to probe mainly NADH, a metabolite, while 266 nm excitation was used to probe mainly tryptophan to correct for non-metabolic signal artifacts. The ratio of autofluorescence intensities derived under these two excitation wavelengths was calculated and its temporal profile was fit to a relaxation model. Time constants were extracted, and longer time constants were associated with kidney dysfunction. Analysis of both the autofluorescence and light scattering images suggests that changes in microstructure tissue morphology, blood absorption spectral characteristics, and pH contribute to the behavior of the observed signal which may be used to obtain tissue functional information and offer predictive capability.

  19. Optical spectroscopy approach for the predictive assessment of kidney functional recovery following ischemic injury

    Science.gov (United States)

    Raman, Rajesh N.; Pivetti, Christopher D.; Rubenchik, Alexander M.; Matthews, Dennis L.; Troppmann, Christoph; Demos, Stavros G.

    2010-02-01

    Tissue that has undergone significant yet unknown amount of ischemic injury is frequently encountered in organ transplantation and trauma clinics. With no reliable real-time method of assessing the degree of injury incurred in tissue, surgeons generally rely on visual observation which is subjective. In this work, we investigate the use of optical spectroscopy methods as a potentially more reliable approach. Previous work by various groups was strongly suggestive that tissue autofluorescence from NADH obtained under UV excitation is sensitive to metabolic response changes. To test and expand upon this concept, we monitored autofluorescence and light scattering intensities of injured vs. uninjured rat kidneys via multimodal imaging under 355 nm, 325 nm, and 266 nm excitation as well as scattering under 500 nm illumination. 355 nm excitation was used to probe mainly NADH, a metabolite, while 266 nm excitation was used to probe mainly tryptophan to correct for non-metabolic signal artifacts. The ratio of autofluorescence intensities derived under these two excitation wavelengths was calculated and its temporal profile was fit to a relaxation model. Time constants were extracted, and longer time constants were associated with kidney dysfunction. Analysis of both the autofluorescence and light scattering images suggests that changes in microstructure tissue morphology, blood absorption spectral characteristics, and pH contribute to the behavior of the observed signal which may be used to obtain tissue functional information and offer predictive capability.

  20. Ultracold atoms in one-dimensional optical lattices approaching the Tonks-Girardeau regime

    International Nuclear Information System (INIS)

    Pollet, L.; Rombouts, S.M.A.; Denteneer, P.J. H.

    2004-01-01

    Recent experiments on ultracold atomic alkali gases in a one-dimensional optical lattice have demonstrated the transition from a gas of soft-core bosons to a Tonks-Girardeau gas in the hard-core limit, where one-dimensional bosons behave like fermions in many respects. We have studied the underlying many-body physics through numerical simulations which accommodate both the soft-core and hard-core limits in one single framework. We find that the Tonks-Girardeau gas is reached only at the strongest optical lattice potentials. Results for slightly higher densities, where the gas develops a Mott-like phase already at weaker optical lattice potentials, show that these Mott-like short-range correlations do not enhance the convergence to the hard-core limit

  1. Supersymmetric approach for Killingbeck radial potential plus noncentral potential in Schrodinger equation

    International Nuclear Information System (INIS)

    Cari, C.; Suparmi, A.; Yunianto, M.; Pratiwi, B. N.

    2016-01-01

    Killingbeck radial potential, which consists of harmonic oscillator, linier and Coulomb potentials, is combined with non-central potential. The solution of three dimensional Schrodinger equation for Killingbeck potential is combined with Poschl-Teller potential and Symmetrical Top non-central potentials are investigated using supersymmetry (SUSY) operator. The non-relativistic energy is obtained which is infuenced by potentials and the wave functions are produced by using SUSY operator. (paper)

  2. Extracting the potential-well of a near-field optical trap using the Helmholtz-Hodge decomposition

    Science.gov (United States)

    Zaman, Mohammad Asif; Padhy, Punnag; Hansen, Paul C.; Hesselink, Lambertus

    2018-02-01

    The non-conservative nature of the force field generated by a near-field optical trap is analyzed. A plasmonic C-shaped engraving on a gold film is considered as the trap. The force field is calculated using the Maxwell stress tensor method. The Helmholtz-Hodge decomposition is used to extract the conservative and the non-conservative component of the force. Due to the non-negligible non-conservative component, it is found that the conventional approach of extracting the potential by direct integration of the force is not accurate. Despite the non-conservative nature of the force field, it is found that the statistical properties of a trapped nanoparticle can be estimated from the conservative component of the force field alone. Experimental and numerical results are presented to support the claims.

  3. A new approach to Ozone Depletion Potential (ODP) estimation

    Science.gov (United States)

    Portmann, R. W.; Daniel, J. S.; Yu, P.

    2017-12-01

    The Ozone Depletion Potential (ODP) is given by the time integrated global ozone loss of an ozone depleting substance (ODS) relative to a reference ODS (usually CFC-11). The ODP is used by the Montreal Protocol (and subsequent amendments) to inform policy decisions on the production of ODSs. Since the early 1990s, ODPs have usually been estimated using an approximate formulism that utilizes the lifetime and the fractional release factor of the ODS. This has the advantage that it can utilize measured concentrations of the ODSs to estimate their fractional release factors. However, there is a strong correlation between stratospheric lifetimes and fractional release factors of ODSs and that this can introduce uncertainties into ODP calculations when the terms are estimated independently. Instead, we show that the ODP is proportional to the average global ozone loss per equivalent chlorine molecule released in the stratosphere by the ODS loss process (which we call the Γ factor) and, importantly, this ratio varies only over a relatively small range ( 0.3-1.5) for ODPs with stratospheric lifetimes of 20 to more than 1,000 years. The Γ factor varies smoothly with stratospheric lifetime for ODSs with loss processes dominated by photolysis and is larger for long-lived species, while stratospheric OH loss processes produce relatively small Γs that are nearly independent of stratospheric lifetime. The fractional release approach does not accurately capture these relationships. We propose a new formulation that takes advantage of this smooth variation by parameterizing the Γ factor using ozone changes computed using the chemical climate model CESM-WACCM and the NOCAR two-dimensional model. We show that while the absolute Γ's vary between WACCM and NOCAR models, much of the difference is removed for the Γ/ΓCFC-11 ratio that is used in the ODP formula. This parameterized method simplifies the computation of ODPs while providing enhanced accuracy compared to the

  4. Tapping Geography's Potential for Synergy with Creative Instructional Approaches

    Science.gov (United States)

    Conway-Gomez, Kristen; Williams, Nikki; Atkinson-Palombo, Carol; Ahlqvist, Ola; Kim, Eje; Morgan, Miranda

    2011-01-01

    We define synergy, explain its importance within the context of rapidly changing academia, and provide examples of how geographic educators have used creative instructional approaches to create synergies. Both the content of geography and some of the instructional approaches used by geographic educators support the discipline's ability to deliver…

  5. Microscopic theory for nucleon-nucleus optical potential in intermediate energies

    International Nuclear Information System (INIS)

    He Guozhu; Cai Chonghai

    1984-01-01

    Based on the scattering theory of KMT and FGH we calculate the nucleon-nucleus optical potentials of 4 He, 16 O and 40 Ca from the Paris N-N potential given by M. Lacombe et al. The real part Vsub(R)(r) of our optential has the form of Woods-Saxon when the kinetic energy E of the incident nucleon is low. The depth of Vsub(R)(r) will decrease as E increases, and it turns into positive in the interior of nucleus when E approx.= 300 MeV. The repulsive effect in the interior of nucleus increases rapidly as E increases even more, butthere always exists some attractive effect at the surface of nucleus. Therefore, Vsub(R)(r) has generally the wine-bottle bottom shape. We also calculate the quatity Jv/N = (4π/N)∫sub(0)sub(infinity)Vsub(R)(r)r 2 dr. Our results are basically in acordance with those of M.Jaminon et al's relativistic Hatree calculation as well as the experimental results. In this work we also calculate the imaginary part of optical potential and its variation with the kinetic energy of the incident nucleon

  6. A wave optics approach to the theory of the Michelson-Morley experiment

    Science.gov (United States)

    Smid, Thomas

    2017-11-01

    A consistent classical wave optics approach to the theory of the Michelson-Morley experiment shows that the original theory as applied by Michelson and Morley and others does not calculate the optical paths of the two beams correctly, primarily because of incorrectly assuming a right angle reflection in the instrument’s reference frame for the transverse beam, but also because of the incorrect assumption of aberration for the wave fronts. The theory presented in this work proves the expected variation of the phase difference when rotating the interferometer to be more than twice as large and also strongly asymmetrical around the zero line.

  7. Stability of trapped Bose—Einstein condensates in one-dimensional tilted optical lattice potential

    International Nuclear Information System (INIS)

    Fang Jian-Shu; Liao Xiang-Ping

    2011-01-01

    Using the direct perturbation technique, this paper obtains a general perturbed solution of the Bose—Einstein condensates trapped in one-dimensional tilted optical lattice potential. We also gave out two necessary and sufficient conditions for boundedness of the perturbed solution. Theoretical analytical results and the corresponding numerical results show that the perturbed solution of the Bose-Einstein condensate system is unbounded in general and indicate that the Bose—Einstein condensates are Lyapunov-unstable. However, when the conditions for boundedness of the perturbed solution are satisfied, then the Bose-Einstein condensates are Lyapunov-stable. (general)

  8. Ionization potential depression and optical spectra in a Debye plasma model

    Science.gov (United States)

    Lin, Chengliang; Röpke, Gerd; Reinholz, Heidi; Kraeft, Wolf-Dietrich

    2017-11-01

    We show how optical spectra in dense plasmas are determined by the shift of energy levels as well as the broadening owing to collisions with the plasma particles. In lowest approximation, the interaction with the plasma particles is described by the RPA dielectric function, leading to the Debye shift of the continuum edge. The bound states remain nearly un-shifted, their broadening is calculated in Born approximation. The role of ionization potential depression as well as the Inglis-Teller effect are shown. The model calculations have to be improved going beyond the lowest (RPA) approximation when applying to WDM spectra.

  9. Spatial chaos of trapped Bose-Einstein condensate in one-dimensional weak optical lattice potential

    International Nuclear Information System (INIS)

    Chong Guishu; Hai Wenhua; Xie Qiongtao

    2004-01-01

    The spatially chaotic attractor in an elongated cloud of Bose-Einstein condensed atoms perturbed by a weak optical lattice potential is studied. The analytical insolvability and numerical incomputability of the atomic number density are revealed by a perturbed solution that illustrates the unpredictability of the deterministic chaos. Although this could lead the nonphysical explosion and unboundedness to the numerical solution, the theoretical analysis offers a criterion to avoid them. Moreover, the velocity field is investigated that exhibits the superfluid property of the chaotic system

  10. Description of nucleon scattering on 208Pb by a fully Lane-consistent dispersive spherical optical model potential

    Science.gov (United States)

    Sun, W. L.; Wang, J.; Soukhovitskii, E. Sh.; Capote, R.; Quesada, J. M.

    2017-09-01

    A fully Lane-consistent dispersive spherical optical potential is proposed to describe nucleon scattering interaction with doubly magic nucleus 208Pb up to 200 MeV. The experimental neutron total cross sections, elastically scattered nucleon angular distributions and (p,n) data had been used to search the potential parameters. Good agreement between experiments and the calculations with this potential is observed. Meanwhile, the application of the determined optical potential with the same parameters to neighbouring near magic Pb-Bi isotopes is also examined to show the predictive power of this potential.

  11. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  12. Meta-shell Approach for Constructing Lightweight and High Resolution X-Ray Optics

    Science.gov (United States)

    McClelland, Ryan S.

    2016-01-01

    Lightweight and high resolution optics are needed for future space-based x-ray telescopes to achieve advances in high-energy astrophysics. Past missions such as Chandra and XMM-Newton have achieved excellent angular resolution using a full shell mirror approach. Other missions such as Suzaku and NuSTAR have achieved lightweight mirrors using a segmented approach. This paper describes a new approach, called meta-shells, which combines the fabrication advantages of segmented optics with the alignment advantages of full shell optics. Meta-shells are built by layering overlapping mirror segments onto a central structural shell. The resulting optic has the stiffness and rotational symmetry of a full shell, but with an order of magnitude greater collecting area. Several meta-shells so constructed can be integrated into a large x-ray mirror assembly by proven methods used for Chandra and XMM-Newton. The mirror segments are mounted to the meta-shell using a novel four point semi-kinematic mount. The four point mount deterministically locates the segment in its most performance sensitive degrees of freedom. Extensive analysis has been performed to demonstrate the feasibility of the four point mount and meta-shell approach. A mathematical model of a meta-shell constructed with mirror segments bonded at four points and subject to launch loads has been developed to determine the optimal design parameters, namely bond size, mirror segment span, and number of layers per meta-shell. The parameters of an example 1.3 m diameter mirror assembly are given including the predicted effective area. To verify the mathematical model and support opto-mechanical analysis, a detailed finite element model of a meta-shell was created. Finite element analysis predicts low gravity distortion and low thermal distortion. Recent results are discussed including Structural Thermal Optical Performance (STOP) analysis as well as vibration and shock testing of prototype meta-shells.

  13. Surgical decompression in endocrine orbitopathy. Visual evoked potential evaluation and effect on the optic nerve.

    Science.gov (United States)

    Clauser, Luigi C; Tieghi, Riccardo; Galie', Manlio; Franco, Filippo; Carinci, Francesco

    2012-10-01

    Endocrine orbitopathy (EO) represents the most frequent and important extrathyroidal stigma of Graves disease. This chronic autoimmune condition involves the orbital contents, including extraocular muscles, periorbital connective-fatty tissue and lacrimal gland. The increase of fat tissue and the enlargement of extraocular muscles within the bony confines of the orbit leads to proptosis, and in the most severe cases optic neuropathy, caused by compression and stretching of the optic nerve. The congestion and the pressure of the enlarged muscles, constrict the nerve and can lead to reduced sight or loss of vision with the so called "orbital apex syndrome". Generally surgical treatment of EO, based on fat and/or orbital wall expansion, is possible and effective in improving exophthalmos and diplopia. Since there are limited reports focussing on optic neuropathy recovery after fat and/or orbital walls decompression the Authors decided to perform a retrospective analysis on a series of patients affected by EO. The study population was composed of 10 patients affected by EO and presenting to the Unit of Cranio Maxillofacial Surgery, Center for Craniofacial Deformities & Orbital Surgery St. Anna Hospital and University, Ferrara, Italy, for evaluation and treatment. A complete Visual Evoked Potentials (VEP) evaluation was performed. There were seven women and three men with a median age of 55 years. Optic nerve VEP amplitude and latency were recorded as normal or pathological. Abnormal results were scored as moderate, mild and severe. Differences in VEP pre and post-operatively were recorded as present or absent (i.e. VEP Delta). Pearson chi square test was applied. There were 20 operated orbits. The first VEP evaluation was performed 3.2 months before surgery and post-operative VEP control was done after a mean of 18.7 months. Fat decompression was performed in all cases and eight patients had also bony decompression. VEP amplitude and latency were affected in 10 and 15

  14. Redox Potentials of Ligands and Complexes – a DFT Approach

    African Journals Online (AJOL)

    NICO

    A review of the limited literature concerned with theoretical ways to predict experimentally measured redox potentials of ligands and ... electrode surface, over-potentials and high solvent resistance, ... A correlation coefficient of 0.969 in the linear relation with ... of E0' were performed in two steps, i.e. calculation of the free.

  15. Meeting Each Student's Unique Potential: One Approach to Education.

    Science.gov (United States)

    Gauld, Joseph W.

    1996-01-01

    By championing extrinsic motivation, the achievement-reward system short-circuits individuals' innate inner power. Achievement-oriented adults rely on their knowledge, skills, and abilities, not their deeper potential. Hyde School, in Bath, Maine, solves this problem by committing the entire school community to development of unique potential via…

  16. The Methodical Approaches to Activation of Innovative Potential of Enterprise

    Directory of Open Access Journals (Sweden)

    Berveno Oksana V.

    2017-12-01

    Full Text Available The article is aimed at developing theoretical provisions and practical recommendations on methods of management and activation of innovative potential of enterprises. Assessment of innovative potential of enterprise should be carried out from different positions, taking into consideration all external and internal possibilities of enterprise as to carrying out an innovation activity. The system of management of innovation activity and implementation of innovative potential at enterprise should be closely woven in the general management of the enterprise. Activation of innovative potential of enterprise foresees adoption of the whole system of strategic decisions, which are aimed at creation of the most favorable conditions for implementation of innovative potential with obtaining of planned results. The system of activization of innovative potential should develop a number of organizational decisions on interaction of elements of the most innovative potential in the process of innovation activity and cooperation of innovative potential with other subsystems of the enterprise. Results of these organizational decisions in many respects determine efficiency of innovation activity of the enterprise.

  17. Recent novel tumor gatekeepers and potential therapeutic approaches

    African Journals Online (AJOL)

    Keywords: Cancer, Potent inhibitors, Gatekeepers, Therapeutic approaches, Oncogenic pathways. Tropical Journal ..... effects of the target suppression support change from a one gene .... Siegel RL, Miller KD, Jemal A. Cancer statistics, 2017.

  18. Semiclassical derivation of a local optical potential for heavy-ion elastic scattering. [Coupling to other processes

    Energy Technology Data Exchange (ETDEWEB)

    Donangelo, R; Canto, L F [Rio de Janeiro Univ. (Brazil). Inst. de Fisica; Hussein, M S [Sao Paulo Univ. (Brazil). Inst. de Fisica

    1979-05-21

    A semiclassical method to determine the contribution to the optical potential in the elastic channel due to the coupling to other processes taking place in heavy-ion collisions is developed. An application is made to the case of Coulomb excitation. The lowest-order term of the potential used is shown to be identical to the potential derived by Baltz et al.

  19. A unified approach for radiative losses and backscattering in optical waveguides

    International Nuclear Information System (INIS)

    Melati, D; Morichetti, F; Melloni, A

    2014-01-01

    Sidewall roughness in optical waveguides represents a severe impairment for the proper functionality of photonic integrated circuits. The interaction between the propagating mode and the roughness is responsible for both radiative losses and distributed backscattering. In this paper, a unified vision on these extrinsic loss phenomena is discussed, highlighting the fundamental role played by the sensitivity of the effective index n eff of the optical mode to waveguide width variations. The n w model presented applies to both 2D slab waveguides and 3D laterally confined waveguides and is in very good agreement with existing models that individually describe radiative loss or backscattering only. Experimental results are presented, demonstrating the validity of the n w model for arbitrary waveguide geometries and technologies. This approach enables an accurate description of realistic optical waveguides and provides simple design rules for optimization of the waveguide geometry in order to reduce the propagation losses generated by sidewall roughness. (paper)

  20. Implementing nonprojective measurements via linear optics: An approach based on optimal quantum-state discrimination

    International Nuclear Information System (INIS)

    Loock, Peter van; Nemoto, Kae; Munro, William J.; Raynal, Philippe; Luetkenhaus, Norbert

    2006-01-01

    We discuss the problem of implementing generalized measurements [positive operator-valued measures (POVMs)] with linear optics, either based upon a static linear array or including conditional dynamics. In our approach, a given POVM shall be identified as a solution to an optimization problem for a chosen cost function. We formulate a general principle: the implementation is only possible if a linear-optics circuit exists for which the quantum mechanical optimum (minimum) is still attainable after dephasing the corresponding quantum states. The general principle enables us, for instance, to derive a set of necessary conditions for the linear-optics implementation of the POVM that realizes the quantum mechanically optimal unambiguous discrimination of two pure nonorthogonal states. This extends our previous results on projection measurements and the exact discrimination of orthogonal states

  1. Geometrical optics approach in liquid crystal films with three-dimensional director variations.

    Science.gov (United States)

    Panasyuk, G; Kelly, J; Gartland, E C; Allender, D W

    2003-04-01

    A formal geometrical optics approach (GOA) to the optics of nematic liquid crystals whose optic axis (director) varies in more than one dimension is described. The GOA is applied to the propagation of light through liquid crystal films whose director varies in three spatial dimensions. As an example, the GOA is applied to the calculation of light transmittance for the case of a liquid crystal cell which exhibits the homeotropic to multidomainlike transition (HMD cell). Properties of the GOA solution are explored, and comparison with the Jones calculus solution is also made. For variations on a smaller scale, where the Jones calculus breaks down, the GOA provides a fast, accurate method for calculating light transmittance. The results of light transmittance calculations for the HMD cell based on the director patterns provided by two methods, direct computer calculation and a previously developed simplified model, are in good agreement.

  2. Planar junctionless phototransistor: A potential high-performance and low-cost device for optical-communications

    Science.gov (United States)

    Ferhati, H.; Djeffal, F.

    2017-12-01

    In this paper, a new junctionless optical controlled field effect transistor (JL-OCFET) and its comprehensive theoretical model is proposed to achieve high optical performance and low cost fabrication process. Exhaustive study of the device characteristics and comparison between the proposed junctionless design and the conventional inversion mode structure (IM-OCFET) for similar dimensions are performed. Our investigation reveals that the proposed design exhibits an outstanding capability to be an alternative to the IM-OCFET due to the high performance and the weak signal detection benefit offered by this design. Moreover, the developed analytical expressions are exploited to formulate the objective functions to optimize the device performance using Genetic Algorithms (GAs) approach. The optimized JL-OCFET not only demonstrates good performance in terms of derived drain current and responsivity, but also exhibits superior signal to noise ratio, low power consumption, high-sensitivity, high ION/IOFF ratio and high-detectivity as compared to the conventional IM-OCFET counterpart. These characteristics make the optimized JL-OCFET potentially suitable for developing low cost and ultrasensitive photodetectors for high-performance and low cost inter-chips data communication applications.

  3. Groundwater Radioiodine: Prevalence, Biogeochemistry, And Potential Remedial Approaches

    International Nuclear Information System (INIS)

    Denham, M.; Kaplan, D.; Yeager, C.

    2009-01-01

    Iodine-129 ( 129 I) has not received as much attention in basic and applied research as other contaminants associated with DOE plumes. These other contaminants, such as uranium, plutonium, strontium, and technetium are more widespread and exist at more DOE facilities. Yet, at the Hanford Site and the Savannah River Site 129 I occurs in groundwater at concentrations significantly above the primary drinking water standard and there is no accepted method for treating it, other than pump-and-treat systems. With the potential arrival of a 'Nuclear Renaissance', new nuclear power facilities will be creating additional 129 I waste at a rate of 1 Ci/gigawatts energy produced. If all 22 proposed nuclear power facilities in the U.S. get approved, they will produce more 129 I waste in seven years than presently exists at the two facilities containing the largest 129 I inventories, (∼146 Ci 129 I at the Hanford Site and the Savannah River Site). Hence, there is an important need to fully understand 129 I behavior in the environment to clean up existing plumes and to support the expected future expansion of nuclear power production. 129 I is among the key risk drivers at all DOE nuclear disposal facilities where 129 I is buried, because of its long half-life (16 million years), high toxicity (90% of the body's iodine accumulates in the thyroid), high inventory, and perceived high mobility in the subsurface environment. Another important reason that 129 I is a key risk driver is that there is the uncertainty regarding its biogeochemical fate and transport in the environment. We typically can define 129 I mass balance and flux at sites, but can not accurately predict its response to changes in the environment. This uncertainty is in part responsible for the low drinking water standard, 1 pCi/L 129 I, and the low permissible inventory limits (Ci) at the Savannah River Site, Hanford Site, and the former Yucca Mountain disposal facilities. The objectives of this report are to: (1

  4. GROUNDWATER RADIOIODINE: PREVALENCE, BIOGEOCHEMISTRY, AND POTENTIAL REMEDIAL APPROACHES

    Energy Technology Data Exchange (ETDEWEB)

    Denham, M.; Kaplan, D.; Yeager, C.

    2009-09-23

    Iodine-129 ({sup 129}I) has not received as much attention in basic and applied research as other contaminants associated with DOE plumes. These other contaminants, such as uranium, plutonium, strontium, and technetium are more widespread and exist at more DOE facilities. Yet, at the Hanford Site and the Savannah River Site {sup 129}I occurs in groundwater at concentrations significantly above the primary drinking water standard and there is no accepted method for treating it, other than pump-and-treat systems. With the potential arrival of a 'Nuclear Renaissance', new nuclear power facilities will be creating additional {sup 129}I waste at a rate of 1 Ci/gigawatts energy produced. If all 22 proposed nuclear power facilities in the U.S. get approved, they will produce more {sup 129}I waste in seven years than presently exists at the two facilities containing the largest {sup 129}I inventories, ({approx}146 Ci {sup 129}I at the Hanford Site and the Savannah River Site). Hence, there is an important need to fully understand {sup 129}I behavior in the environment to clean up existing plumes and to support the expected future expansion of nuclear power production. {sup 129}I is among the key risk drivers at all DOE nuclear disposal facilities where {sup 129}I is buried, because of its long half-life (16 million years), high toxicity (90% of the body's iodine accumulates in the thyroid), high inventory, and perceived high mobility in the subsurface environment. Another important reason that {sup 129}I is a key risk driver is that there is the uncertainty regarding its biogeochemical fate and transport in the environment. We typically can define {sup 129}I mass balance and flux at sites, but can not accurately predict its response to changes in the environment. This uncertainty is in part responsible for the low drinking water standard, 1 pCi/L {sup 129}I, and the low permissible inventory limits (Ci) at the Savannah River Site, Hanford Site, and the

  5. Single-resolution and multiresolution extended-Kalman-filter-based reconstruction approaches to optical refraction tomography.

    Science.gov (United States)

    Naik, Naren; Vasu, R M; Ananthasayanam, M R

    2010-02-20

    The problem of reconstruction of a refractive-index distribution (RID) in optical refraction tomography (ORT) with optical path-length difference (OPD) data is solved using two adaptive-estimation-based extended-Kalman-filter (EKF) approaches. First, a basic single-resolution EKF (SR-EKF) is applied to a state variable model describing the tomographic process, to estimate the RID of an optically transparent refracting object from noisy OPD data. The initialization of the biases and covariances corresponding to the state and measurement noise is discussed. The state and measurement noise biases and covariances are adaptively estimated. An EKF is then applied to the wavelet-transformed state variable model to yield a wavelet-based multiresolution EKF (MR-EKF) solution approach. To numerically validate the adaptive EKF approaches, we evaluate them with benchmark studies of standard stationary cases, where comparative results with commonly used efficient deterministic approaches can be obtained. Detailed reconstruction studies for the SR-EKF and two versions of the MR-EKF (with Haar and Daubechies-4 wavelets) compare well with those obtained from a typically used variant of the (deterministic) algebraic reconstruction technique, the average correction per projection method, thus establishing the capability of the EKF for ORT. To the best of our knowledge, the present work contains unique reconstruction studies encompassing the use of EKF for ORT in single-resolution and multiresolution formulations, and also in the use of adaptive estimation of the EKF's noise covariances.

  6. An Inertial and Optical Sensor Fusion Approach for Six Degree-of-Freedom Pose Estimation

    Science.gov (United States)

    He, Changyu; Kazanzides, Peter; Sen, Hasan Tutkun; Kim, Sungmin; Liu, Yue

    2015-01-01

    Optical tracking provides relatively high accuracy over a large workspace but requires line-of-sight between the camera and the markers, which may be difficult to maintain in actual applications. In contrast, inertial sensing does not require line-of-sight but is subject to drift, which may cause large cumulative errors, especially during the measurement of position. To handle cases where some or all of the markers are occluded, this paper proposes an inertial and optical sensor fusion approach in which the bias of the inertial sensors is estimated when the optical tracker provides full six degree-of-freedom (6-DOF) pose information. As long as the position of at least one marker can be tracked by the optical system, the 3-DOF position can be combined with the orientation estimated from the inertial measurements to recover the full 6-DOF pose information. When all the markers are occluded, the position tracking relies on the inertial sensors that are bias-corrected by the optical tracking system. Experiments are performed with an augmented reality head-mounted display (ARHMD) that integrates an optical tracking system (OTS) and inertial measurement unit (IMU). Experimental results show that under partial occlusion conditions, the root mean square errors (RMSE) of orientation and position are 0.04° and 0.134 mm, and under total occlusion conditions for 1 s, the orientation and position RMSE are 0.022° and 0.22 mm, respectively. Thus, the proposed sensor fusion approach can provide reliable 6-DOF pose under long-term partial occlusion and short-term total occlusion conditions. PMID:26184191

  7. Bragg diffraction of fermions at optical potentials; Braggbeugung von Fermionen an optischen Potentialen

    Energy Technology Data Exchange (ETDEWEB)

    Deh, Benjamin

    2008-10-27

    This thesis describes the Bragg diffraction of ultracold fermions at an optical potential. A moving optical lattice was created, by overlaying two slightly detuned lasers. Atoms can be diffracted at this lattice if the detuning fulfills the Bragg condition for resting atoms. This Bragg diffraction is analyzed systematically in this thesis. To this end Rabi oscillations between the diffraction states were driven, as well in the weakly interacting Bragg regime, as in the strongly interacting Kapitza-Dirac regime. Simulations, based on a driven two-, respectively multilevel-system describe the observed effects rather well. Furthermore, the temporal evolution of the diffracted states in the magnetic trapping potential was studied. The anharmonicity of the trap in use and the scattering cross section for p-wave collisions in a {sup 6}Li system was determined from the movement of these states. Moreover the momentum distribution of the fermions was measured with Bragg spectroscopy and first signs of Fermi degeneracy were found. Finally an interferometer with fermions was build, exhibiting a coherence time of more than 100 {mu}s. With this, the possibility for measurement and manipulation of ultracold fermions with Bragg diffraction could bee shown. (orig.)

  8. Development of a Strontium Magneto-Optical Trap for Probing Casimir-Polder Potentials

    Science.gov (United States)

    Martin, Paul J.

    In recent years, cold atoms have been the centerpiece of many remarkably sensitive measurements, and much effort has been made to devise miniaturized quantum sensors and quantum information processing devices. At small distances, however, mechanical effects of the quantum vacuum begin to significantly impact the behavior of the cold-atom systems. A better understanding of how surface composition and geometry affect Casimir and Casimir-Polder potentials would benefit future engineering of small-scale devices. Unfortunately, theoretical solutions are limited and the number of experimental techniques that can accurately detect such short-range forces is relatively small. We believe the exemplary properties of atomic strontium--which have enabled unprecedented frequency metrology in optical lattice clocks--make it an ideal candidate for probing slight spectroscopic perturbations caused by vacuum fluctuations. To that end, we have constructed a magneto-optical trap for strontium to enable future study of atom-surface potentials, and the apparatus and proposed detection scheme are discussed herein. Of special note is a passively stable external-cavity diode laser we developed that is both affordable and competitive with high-end commercial options.

  9. Study of interaction in silica glass via model potential approach

    Science.gov (United States)

    Mann, Sarita; Rani, Pooja

    2016-05-01

    Silica is one of the most commonly encountered substances in daily life and in electronics industry. Crystalline SiO2 (in several forms: quartz, cristobalite, tridymite) is an important constituent of many minerals and gemstones, both in pure form and mixed with related oxides. Cohesive energy of amorphous SiO2 has been investigated via intermolecular potentials i.e weak Van der Waals interaction and Morse type short-range interaction. We suggest a simple atom-atom based Van der Waals as well as Morse potential to find cohesive energy of glass. It has been found that the study of silica structure using two different model potentials is significantly different. Van der Waals potential is too weak (P.E =0.142eV/molecule) to describe the interaction between silica molecules. Morse potential is a strong potential, earlier given for intramolecular bonding, but if applied for intermolecular bonding, it gives a value of P.E (=-21.92eV/molecule) to appropriately describe the structure of silica.

  10. Study of interaction in silica glass via model potential approach

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Sarita, E-mail: saritaiitr2003@gmail.com [Department of Physics, Panjab University, Chandigarh-160014 (India); Rani, Pooja [D.A.V. College, Sec-10, Chandigarh-160010 (India)

    2016-05-06

    Silica is one of the most commonly encountered substances in daily life and in electronics industry. Crystalline SiO{sub 2} (in several forms: quartz, cristobalite, tridymite) is an important constituent of many minerals and gemstones, both in pure form and mixed with related oxides. Cohesive energy of amorphous SiO{sub 2} has been investigated via intermolecular potentials i.e weak Van der Waals interaction and Morse type short-range interaction. We suggest a simple atom-atom based Van der Waals as well as Morse potential to find cohesive energy of glass. It has been found that the study of silica structure using two different model potentials is significantly different. Van der Waals potential is too weak (P.E =0.142eV/molecule) to describe the interaction between silica molecules. Morse potential is a strong potential, earlier given for intramolecular bonding, but if applied for intermolecular bonding, it gives a value of P.E (=−21.92eV/molecule) to appropriately describe the structure of silica.

  11. Action Potential Dynamics in Fine Axons Probed with an Axonally Targeted Optical Voltage Sensor.

    Science.gov (United States)

    Ma, Yihe; Bayguinov, Peter O; Jackson, Meyer B

    2017-01-01

    The complex and malleable conduction properties of axons determine how action potentials propagate through extensive axonal arbors to reach synaptic terminals. The excitability of axonal membranes plays a major role in neural circuit function, but because most axons are too thin for conventional electrical recording, their properties remain largely unexplored. To overcome this obstacle, we used a genetically encoded hybrid voltage sensor (hVOS) harboring an axonal targeting motif. Expressing this probe in transgenic mice enabled us to monitor voltage changes optically in two populations of axons in hippocampal slices, the large axons of dentate granule cells (mossy fibers) in the stratum lucidum of the CA3 region and the much finer axons of hilar mossy cells in the inner molecular layer of the dentate gyrus. Action potentials propagated with distinct velocities in each type of axon. Repetitive firing broadened action potentials in both populations, but at an intermediate frequency the degree of broadening differed. Repetitive firing also attenuated action potential amplitudes in both mossy cell and granule cell axons. These results indicate that the features of use-dependent action potential broadening, and possible failure, observed previously in large nerve terminals also appear in much finer unmyelinated axons. Subtle differences in the frequency dependences could influence the propagation of activity through different pathways to excite different populations of neurons. The axonally targeted hVOS probe used here opens up the diverse repertoire of neuronal processes to detailed biophysical study.

  12. Time-and-frequency domains approach to data processing in multiwavelength optical scatterometry of dielectric gratings

    KAUST Repository

    Granet, Gérard

    2013-01-01

    This paper focuses on scatterometry problems arising in lithography production of periodic gratings. Namely, the paper introduces a theoretical and numerical-modeling-oriented approach to scatterometry problems and discusses its capabilities. The approach allows for reliable detection of deviations in gratings\\' critical dimensions (CDs) during the manufacturing process. The core of the approach is the one-to-one correspondence between the electromagnetic (EM) characteristics and the geometric/material properties of gratings. The approach is based on highly accurate solutions of initial boundary-value problems describing EM waves\\' interaction on periodic gratings. The advantage of the approach is the ability to perform simultaneously and interactively both in frequency and time domains under conditions of possible resonant scattering of EM waves by infinite or finite gratings. This allows a detection of CDs for a wide range of gratings, and, thus is beneficial for the applied scatterometry. (C) 2013 Optical Society of America

  13. Time-and-frequency domains approach to data processing in multiwavelength optical scatterometry of dielectric gratings

    KAUST Repository

    Granet, Gé rard; Melezhik, Petr N.; Sirenko, Kostyantyn; Yashina, Nataliya P.

    2013-01-01

    This paper focuses on scatterometry problems arising in lithography production of periodic gratings. Namely, the paper introduces a theoretical and numerical-modeling-oriented approach to scatterometry problems and discusses its capabilities. The approach allows for reliable detection of deviations in gratings' critical dimensions (CDs) during the manufacturing process. The core of the approach is the one-to-one correspondence between the electromagnetic (EM) characteristics and the geometric/material properties of gratings. The approach is based on highly accurate solutions of initial boundary-value problems describing EM waves' interaction on periodic gratings. The advantage of the approach is the ability to perform simultaneously and interactively both in frequency and time domains under conditions of possible resonant scattering of EM waves by infinite or finite gratings. This allows a detection of CDs for a wide range of gratings, and, thus is beneficial for the applied scatterometry. (C) 2013 Optical Society of America

  14. Combinatorial mutagenesis of the voltage-sensing domain enables the optical resolution of action potentials firing at 60 Hz by a genetically encoded fluorescent sensor of membrane potential.

    Science.gov (United States)

    Piao, Hong Hua; Rajakumar, Dhanarajan; Kang, Bok Eum; Kim, Eun Ha; Baker, Bradley J

    2015-01-07

    ArcLight is a genetically encoded fluorescent voltage sensor using the voltage-sensing domain of the voltage-sensing phosphatase from Ciona intestinalis that gives a large but slow-responding optical signal in response to changes in membrane potential (Jin et al., 2012). Fluorescent voltage sensors using the voltage-sensing domain from other species give faster yet weaker optical signals (Baker et al., 2012; Han et al., 2013). Sequence alignment of voltage-sensing phosphatases from different species revealed conserved polar and charged residues at 7 aa intervals in the S1-S3 transmembrane segments of the voltage-sensing domain, suggesting potential coil-coil interactions. The contribution of these residues to the voltage-induced optical signal was tested using a cassette mutagenesis screen by flanking each transmembrane segment with unique restriction sites to allow for the testing of individual mutations in each transmembrane segment, as well as combinations in all four transmembrane segments. Addition of a counter charge in S2 improved the kinetics of the optical response. A double mutation in the S4 domain dramatically reduced the slow component of the optical signal seen in ArcLight. Combining that double S4 mutant with the mutation in the S2 domain yielded a probe with kinetics voltage-sensing domain could potentially lead to fluorescent sensors capable of optically resolving neuronal inhibition and subthreshold synaptic activity. Copyright © 2015 the authors 0270-6474/15/350372-15$15.00/0.

  15. Adapting advanced engineering design approaches to building design - potential benefits

    NARCIS (Netherlands)

    Hopfe, C.J.; Struck, C.; Hensen, J.L.M.; Böhms, M.

    2006-01-01

    A number of industries continuously progress advancing their design approaches based on the changing market constraints. Examples such as car, ship and airplane manufacturing industries utilize process setups and techniques, that differ significantly from the processes and techniques used by the

  16. Adapting advanced engineering design approaches to building design. Potential benefits

    NARCIS (Netherlands)

    Böhms, M.

    2006-01-01

    A number of industries continuously progress advancing their design approaches based on the changing market constraints. Examples such as car, ship and airplane manufacturing industries utilize process setups and techniques, that differ significantly from the processes and techniques used by the

  17. Approximate Approaches to the One-Dimensional Finite Potential Well

    Science.gov (United States)

    Singh, Shilpi; Pathak, Praveen; Singh, Vijay A.

    2011-01-01

    The one-dimensional finite well is a textbook problem. We propose approximate approaches to obtain the energy levels of the well. The finite well is also encountered in semiconductor heterostructures where the carrier mass inside the well (m[subscript i]) is taken to be distinct from mass outside (m[subscript o]). A relevant parameter is the mass…

  18. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  19. ASYMPTOTICAL CALCULATION OF ELECTROMAGNETIC WAVES SCATTERED FROM A DIELECTRIC COATED CYLINDRICAL SURFACE WITH PHYSICAL OPTICS APPROACH

    Directory of Open Access Journals (Sweden)

    Uğur YALÇIN

    2004-02-01

    Full Text Available In this study, quasi-optical scattering of finite source electromagnetic waves from a dielectric coated cylindrical surface is analysed with Physical Optics (PO approach. A linear electrical current source is chosen as the finite source. Reflection coefficient of the cylindrical surface is derived by using Geometrical Theory of Diffraction (GTD. Then, with the help of this coefficient, fields scattered from the surface are obtained. These field expressions are used in PO approach and surface scattering integral is determined. Evaluating this integral asymptotically, fields reflected from the surface and surface divergence coefficient are calculated. Finally, results obtained in this study are evaluated numerically and effects of the surface impedance to scattered fields are analysed. The time factor is taken as j te? in this study.

  20. Novel Combinatory Approaches to Repair Visual System after Optic Nerve Damage

    Science.gov (United States)

    2014-09-01

    Novel Combinatory Approaches to Repair Visual System After Optic Nerve Damage 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...biological functions such as metabolism, growth, cell cycle, and survival ( Cardone et al., 1998; Diehl, Cheng, Roussel, & Sherr, 1998; Hers, Vincent...of injured adult sensory neurons. The Journal of Neuroscience, 21, 7161–7170. Cardone , M. H., Roy, N., Stennicke, H. R., Salvesen, G. S., Franke, T. F

  1. /sup 58,60,62/Ni (. cap alpha. ,p) three--nucleon transfer reactions and. cap alpha. optical potential ambiguities

    Energy Technology Data Exchange (ETDEWEB)

    Yuanda, Wang; Xiuming, Bao; Zhiqiang, Mao; Rongfang, Yuan; Keling, Wen; Binyin, Huang; Zhifu, Wang; Shuming, Li; Jianan, Wang; Zuxun, Sun; others, and

    1985-11-01

    The differential cross sections are measured using 26.0 MeV ..cap alpha.. particle for /sup 58,62/Ni(..cap alpha.., ..cap alpha..) /sup 58,62/Ni and /sup 58,62/Ni(..cap alpha..,p) /sup 61,65/Cu reactions as well as 25.4 MeV ..cap alpha.. particle for /sup 60/Ni(..cap alpha.., ..cap alpha..)/sup 69/Ni and /sup 60/Ni(..cap alpha.., p)/sup 63/Cu reactions. Consistent calculations with optical model and ZR DWBA are made for (..cap alpha.., ..cap alpha..) and (..cap alpha.., p) reactions by using of single, two, three and four nucleon optical potential parameters. For elastic scattering due to the ..cap alpha.. optical potential ambiguities, all the above optical potential can reproduce the experimental angular distributions. However, the single, two and three nucleon potential, including the Baird's mass systematics and the Chang's energy systematics of ..cap alpha.. potentials, obviously can not provide a reasonable fitting with the (..cap alpha..,p) reaction experimental data. Only the results from the four nucleon potential is in good agreement with the (..cap alpha..,p) reaction experimental data. This reveals that in the ..cap alpha..-particle induced transfer reactions, the real depth of the ..cap alpha..-nucleus optical potential should be rather deep.

  2. The potential of optically stimulated luminescence for medieval building; A case study at Termez, Uzbekistan

    International Nuclear Information System (INIS)

    Vieillevigne, Emmanuelle; Guibert, Pierre; Rita Zuccarello, Agnese; Bechtel, Francoise

    2006-01-01

    Luminescence techniques thermoluminescence (TL) and optically stimulated luminescence (OSL) are generally used to assess the chronology of the last firing of ceramics. In the field of building archaeology, fired bricks can be dated by these techniques. Nevertheless, these luminescence ages are not exactly related to the construction of the building itself, but to the production of the building materials. In some cases, re-use is possible and this raises problems with the interpretation of the dating results. This led us to employ optically stimulated luminescence in a less conventional way. Before bricks were sealed in masonry by mortar, they would have been exposed to day light, and, as a result, the optical traps of the crystals on the material surface should have been bleached (zeroed by light). Dating the end of the bleaching period is possible by OSL using blue light for stimulation and by IRSL (infrared stimulated luminescence) using IR stimulation. Thus the OSL or IRSL age for these crystals is directly related to the construction of the architectural structure. Experiments were carried out to determine the suitability of this approach and to solve practical problems of sampling. The results show that the bleaching light penetrates between 0.5 to 1 mm into the bricks, according to their transparency. This depth is sufficient to collect enough quartz and feldspar inclusions that have been affected by light in the past, and thus date the construction of the masonry directly. Attempts at surface dating of bricks collected at the medieval citadel of Termez, Uzbekistan, already dated by TL, were the starting point of this research

  3. The potential of endogenous learning approaches to gender and ...

    African Journals Online (AJOL)

    USER

    Abstract. This paper argues for a middle-inclusive ground within multiple feminist perspectives from which the potential for ... 5 RWAMREC is a non-governmental organization whose vision is to, “Create a society where women and men share roles and ..... environment (The East African Community Secretariat, 2009).

  4. Integrated approach for identification of potential groundwater zones ...

    Indian Academy of Sciences (India)

    The population density of the area is 370 person per sq. km. .... The depth of bore wells on average ranges from 40 to 80m with a ..... draw down pumping test which showed optimum yield of ... izontally stratified earth; Geophysical Prospecting 19. 769–775. ... groundwater potential of India – an estimate based on injected ...

  5. Technical Approaches For Implementation Of CSMA/CD On A Fiber Optic Medium

    Science.gov (United States)

    Cronin, William J.

    1990-01-01

    The IEEE 802.3 10BASE-F Task Force is currently working on two approaches for 10 Megabit per second CSMA/CD networks using fiber optic media. The two approaches have distinct application spaces. One approach is based on Passive Fiber Optic Star technology, the other on Active Star technology. One standard, covering both application spaces, is expected sometime in 1991. This paper will summarize the proposals presented to the committee, and its predecessors, over the last two years. Three types of proposals were considered for the Active Star application space. These included CSMA/CD on a ring topology, an Active Star based on the Fiber Optic Inter Repeater Link, and an Active Star based on a synchronous signaling scheme. Three proposals were considered for the Passive Star application space. These included techniques for detecting collisions via special pulses, code rule violations, and amplitude sensing techniques. The paper concludes with a summary of the proposals being standardized by the 10BASE-F Task Force.

  6. Czechoslovak approach to the potential of HTGRs' introduction

    International Nuclear Information System (INIS)

    Jakesova, L.; Podest, M.; Pinkas, V.

    1990-01-01

    Czechoslovakia - a rather small country with developed utilization of nuclear electricity production in the Soviet types of PWRs - WWERs - is looking forward to the prospects of high-temperature heat provision for processes enabling better utilization of brown coal resources, in the first range with view to the ecology impact improvement. The introduction of the HTGRs could be the best way to solve these problems in the most convenient approach - i.e. through the international co-operation with the USSR. (author)

  7. Optical model potential analysis of n ¯A and n A interactions

    Science.gov (United States)

    Lee, Teck-Ghee; Wong, Cheuk-Yin

    2018-05-01

    We use a momentum-dependent optical model potential to analyze the annihilation cross sections of the antineutron n ¯ on C, Al, Fe, Cu, Ag, Sn, and Pb nuclei for projectile momenta plab ≲500 MeV /c . We obtain a good description of annihilation cross section data of Barbina et al. [Nucl. Phys. A 612, 346 (1997), 10.1016/S0375-9474(96)00331-4] and of Astrua et al. [Nucl. Phys. A 697, 209 (2002), 10.1016/S0375-9474(01)01252-0] which exhibit an interesting dependence of the cross sections on plab as well as on the target mass number A . We also obtain the neutron (n ) nonelastic reaction cross sections for the same targets. Comparing the n A reaction cross sections σrecn A to the n ¯A annihilation cross sections σannn ¯A, we find that σannn ¯A is significantly larger than σrecn A, that is, the σannn ¯A/σrecn A cross section ratio lies between the values of about 1.5 to 4.0 in the momentum region where comparison is possible. The dependence of the n ¯ annihilation cross section on the projectile charge is also examined in comparison with the antiproton p ¯. Here we predict the p ¯A annihilation cross section on the simplest assumption that both p ¯A and n ¯A interactions have the same nuclear part of the optical potential but differ only in the electrostatic Coulomb interaction. Deviation from a such simple model extrapolation in measurements will provide new information on the difference between n ¯A and p ¯A potentials.

  8. An optical sensing approach for the noninvasive transdermal monitoring of cortisol

    Science.gov (United States)

    Hwang, Yongsoon; Gupta, Niraj K.; Ojha, Yagya R.; Cameron, Brent D.

    2016-03-01

    Cortisol, a biomarker of stress, has recently been shown to have potential in evaluating the physiological state of individuals diagnosed with stress-related conditions including chronic fatigue syndrome. Noninvasive techniques to extract biomarkers from the body are a topic of considerable interest. One such technique to achieve this is known as reverse iontophoresis (RI) which is capable of extracting biomolecules through the skin. Unfortunately, however, the extracted levels are often considerably lower in concentration than those found in blood, thereby requiring a very sensitive analytical method with a low limit of detection. A promising sensing approach, which is well suited to handle such samples, is Surface Plasmon Resonance (SPR) spectroscopy. When coupled with aptamer modified surfaces, such sensors can achieve both selectivity and the required sensitivity. In this study, fabrication and characterization of a RIbased SPR biosensor for the measurement of cortisol has been developed. The optical mount and diffusion cell were both fabricated through the use of 3D printing techniques. The SPR sensor was configured to employ a prism couplerbased arrangement with a laser generation module and CCD line sensor. Cortisol-specific DNA aptamers were immobilized onto a gold surface to achieve the necessary selectivity. For demonstration purposes, cortisol was extracted by the RI system using a skin phantom flow system capable of generating time dependent concentration profiles. The captured sample was then transported using a micro-fluidic platform from the RI collection site to the SPR sensor for real-time monitoring. Analysis and system control was accomplished within a developed LabVIEW® program.

  9. Developmental impairment of compound action potential in the optic nerve of myelin mutant taiep rats.

    Science.gov (United States)

    Roncagliolo, Manuel; Schlageter, Carol; León, Claudia; Couve, Eduardo; Bonansco, Christian; Eguibar, José R

    2006-01-05

    The taiep rat is a myelin mutant with an initial hypomyelination, followed by a progressive demyelination of the CNS. The neurological correlates start with tremor, followed by ataxia, immobility episodes, epilepsy and paralysis. The optic nerve, an easily-isolable central tract fully myelinated by oligodendrocytes, is a suitable preparation to evaluate the developmental impairment of central myelin. We examined the ontogenic development of optic nerve compound action potentials (CAP) throughout the first 6 months of life of control and taiep rats. Control optic nerves (ON) develop CAPs characterized by three waves. Along the first month, the CAPs of taiep rats showed a delayed maturation, with lower amplitudes and longer latencies than controls; at P30, the conduction velocity has only a third of the normal value. Later, as demyelination proceeds, the conduction velocity of taiep ONs begins to decrease and CAPs undergo a gradual temporal dispersion. CAPs of control and taiep showed differences in their pharmacological sensitivity to TEA and 4-AP, two voltage dependent K+ channel-blockers. As compared with TEA, 4-AP induced a significant increase of the amplitudes and a remarkable broadening of CAPs. After P20, unlike controls, the greater sensitivity to 4-AP exhibited by taiep ONs correlates with the detachment and retraction of paranodal loops suggesting that potassium conductances could regulate the excitability as demyelination of CNS axons progresses. It is concluded that the taiep rat, a long-lived mutant, provides a useful model to study the consequences of partial demyelination and the mechanisms by which glial cells regulate the molecular organization and excitability of axonal membranes during development and disease.

  10. Multiple Scattering Approach to Continuum State with Generally Shaped Potential

    International Nuclear Information System (INIS)

    Hatada, Keisuke; Hayakawa, Kuniko; Tenore, Antonio; Benfatto, Maurizio; Natoli, Calogero

    2007-01-01

    We present a new scheme for solving the scattering problem for an arbitrarily shaped potential cell that avoids the well known convergence problems in the angular momentum expansion of the cell shape function. Tests of the method against analytically soluble separable model potentials, with and without shape truncation, have been performed with success. By a judicious choice of the shape of the cells partitioning the whole molecular space and use of empty cells when necessary, we set up a multiple scattering scheme that leads to a straightforward generalization of the same equations in the muffin-tin approximation. For example lmax in the angular momentum expansion can still be chosen according to the rule lmax ∼ kR, where R is the radius of the bounding sphere of the cell and all the matrices appearing in the theory are square matrices

  11. Experimental approaches to predict allergenic potential of novel food

    DEFF Research Database (Denmark)

    Madsen, Charlotte Bernhard; Kroghsbo, Stine; Bøgh, Katrine Lindholm

    2013-01-01

    ’t know under what circumstances oral tolerance develops. With all these unanswered questions, it is a big challenge to designan animal model that, with relatively few animals, is able to predict if a food protein is a potential allergen. An even larger challenge is to predict its potency, a prerequisite...... for risk evaluation.Attempts have been made to rank proteins according to their allergenic potency based on the magnitude of the IgE response in experimental animals. This ranking has not included abundance as a parameter. We may be able to predict potential allergenicity i.e. hazard but our lack......There are many unanswered questions relating to food allergy sensitization in humans. We don’t know under what circumstances sensitization takes place i.e. route (oral, dermal, respiratory), age, dose, frequencyof exposure, infection or by-stander effect of other allergens. In addition we don...

  12. Volcanostratigraphic Approach for Evaluation of Geothermal Potential in Galunggung Volcano

    Science.gov (United States)

    Ramadhan, Q. S.; Sianipar, J. Y.; Pratopo, A. K.

    2016-09-01

    he geothermal systems in Indonesia are primarily associated with volcanoes. There are over 100 volcanoes located on Sumatra, Java, and in the eastern part of Indonesia. Volcanostratigraphy is one of the methods that is used in the early stage for the exploration of volcanic geothermal system to identify the characteristics of the volcano. The stratigraphy of Galunggung Volcano is identified based on 1:100.000 scale topographic map of Tasikmalaya sheet, 1:50.000 scale topographic map and also geological map. The schematic flowchart for evaluation of geothermal exploration is used to interpret and evaluate geothermal potential in volcanic regions. Volcanostratigraphy study has been done on Galunggung Volcano and Talaga Bodas Volcano, West Java, Indonesia. Based on the interpretation of topographic map and analysis of the dimension, rock composition, age and stress regime, we conclude that both Galunggung Volcano and Talaga Bodas Volcano have a geothermal resource potential that deserve further investigation.

  13. Newer Approaches to Identify Potential Untoward Effects in Functional Foods.

    Science.gov (United States)

    Marone, Palma Ann; Birkenbach, Victoria L; Hayes, A Wallace

    2016-01-01

    Globalization has greatly accelerated the numbers and variety of food and beverage products available worldwide. The exchange among greater numbers of countries, manufacturers, and products in the United States and worldwide has necessitated enhanced quality measures for nutritional products for larger populations increasingly reliant on functionality. These functional foods, those that provide benefit beyond basic nutrition, are increasingly being used for their potential to alleviate food insufficiency while enhancing quality and longevity of life. In the United States alone, a steady import increase of greater than 15% per year or 24 million shipments, over 70% products of which are food related, is regulated under the Food and Drug Administration (FDA). This unparalleled growth has resulted in the need for faster, cheaper, and better safety and efficacy screening methods in the form of harmonized guidelines and recommendations for product standardization. In an effort to meet this need, the in vitro toxicology testing market has similarly grown with an anticipatory 15% increase between 2010 and 2015 of US$1.3 to US$2.7 billion. Although traditionally occupying a small fraction of the market behind pharmaceuticals and cosmetic/household products, the scope of functional food testing, including additives/supplements, ingredients, residues, contact/processing, and contaminants, is potentially expansive. Similarly, as functional food testing has progressed, so has the need to identify potential adverse factors that threaten the safety and quality of these products. © The Author(s) 2015.

  14. Approaches to mastering the uranium potential of Cameroon

    International Nuclear Information System (INIS)

    Chakam Tagheu, P.; Simo, A.

    2014-01-01

    Uranium deposits are spread over the five continents. According to the International Atomic Energy Agency (IAEA) estimation in 2009, the global reserves of economically recoverable uranium are estimated at 4.5 million tonnes. In 2012, the world production of uranium was about 54,610 tonnes and the main producers were Kazakhstan (36%), Canada (15%) and Australia (12%). Brazil, Russia, China, India productions accounted for 9.4% of the overall world production. Significant deposits also exist in Africa including Cameroon; those currently in mining stage are in Namibia, Malawi, and Niger. Cameroon has significant mineral deposits such as gold, alluvial diamonds, iron, bauxite and uranium. All of them are still in the exploration stage. Although Cameroon has not launched a nuclear power programme, the mining of its uranium resources is considered as an important component of the national economy. Many uranium occurrences have so far been discovered in Cameroon. They include Kitongo, Salaki, Mayo Nielse and Teubang in the Northern region and Ngombas near Lolodorf in the Southern region. The Cameroon Government is engaged in (i) the assessment of the U-ore resource through drilling, and (ii) the airborne geophysical survey of mining potentials areas. The result of these studies may lead to a better estimation of the national uranium potential. This paper aims at pointing out constraints to assess the uranium potential of Cameroon and proposes measures that could improve on the leveraging of exploitation of this mineral. (author)

  15. Left ventricular approach for recording His bundle potential in man.

    Science.gov (United States)

    Lee, Y S; Lien, W P

    1975-06-01

    The electrical potentials of the His bundle (HB) were recorded from the left ventricular endocardial surface in 28 patients ranging from 16 to 63 years of age. In 14 of the patients the left bundle branch (LB) potentials were also obtained. Placement of a bipolar electrode catheter tip toward the interventricular septum, right at and also 1 to 2 cm below the aortic valve, resulted in stable recordings of both potentials in successive cardiac cycles even at performing atrial or HB pacing from the right heart. The following intervals were measured in milliseconds (msec): P-A, A-H, H, H-V, LB, and LB-V. The average values in 12 patients (average age 26 plus or minus 7 years and average heart rate 90 plus or minus 16 beats per minute) with normal A-V conduction were as follows: P-A 28 plus or minus 7, A-H 76 plus or minus 16, H 19 plus or minus 3 and H-V 45 plus or minus 6 msec. The average values for LB and LB-V in 10 of these 12 patients were 15 plus or minus 3 and 25 plus or minus 3 msec respectively. Validation of the His bundle electrogram (HBE) from the left ventricular endocardial surface was based on simultaneous recordings of the intracardiac electrograms from both left and right sides of the heart in 18 patients. The individual average values for the intervals obtained from both sides of the heart in these patients were statistically not different, except that the H potential was slightly longer in duration fr m the left heart (P equals 0.05). Among these, 16 showed simultaneous onset of the H potentials, and the LB-V and RB-V conduction times from comparable points were almost the same. Indications for the left sided electro-physiologic studies include the following situations: (a) inability to record H from the right of the heart; (b) giant right atrium; and (c) possibly during atrial fibrillation.

  16. An optical system with potential for remote health monitoring of subsea machinery

    International Nuclear Information System (INIS)

    Jackson, D A

    2009-01-01

    A prototype fibre-optic sensing system is described with potential to remotely monitor the condition of three-phase variable frequency subsea motors and electric submersible pumps. An indication that the integrity of a powerful electric motor may be compromised can be gained by spectral analysis of the stator drive current, the phases of the currents, the measurement of vibration at specific locations on the motor and the temperature of the bearings. The optical interrogation system is based on an imbalanced Mach–Zehnder fibre interferometer, illuminated with a broadband source with fibre Bragg gratings (FBGs) used as the basic transducers for the current and vibration measurements. Signals were recovered at a distance of 7 km, for the 'in house' current sensor at an effective ac current of 500 A at frequencies from 10 to 1000 Hz with a S/N ratio of 45 dB, together with the relative phases between the currents. These signals were generated with a simulated high power three-phase electric motor. A commercial accelerometer was incorporated into the system which demonstrated a sensitivity of 1 mg Hz −1/2 also from 10 to 1000 Hz. As the interrogation system can only be used to detect dynamic signals, a second interrogation for quasi-static temperature measurements is required; although this was not deployed, possible applications other than bearing temperature measurement are considered

  17. Potential prospects in archaeological research by using optical spectroscopy through a black glass ocular

    Science.gov (United States)

    Cosyns, P.; Meulebroeck, W.; Thienpont, H.; Nys, K.

    The aim of this paper is to draw attention to the potential usefulness of optical spectroscopy within the archaeological discourse. We therefore use the standardized color coordinates and the transmittance spectra in the region between 350- 1650 nm of nine fragmented Roman black glass artifacts from archaeological contexts in Avenches (Switzerland) and an intact piece from Tongeren (Belgium). Firstly, we demonstrate how the use of UV-Vis-NIR spectroscopy can help the archaeologist in understanding the various excavated features containing glass artifacts. The analysis of the optical spectra of Roman black glass artifacts demonstrates in the first place that an object has a very homogenous composition. The clustering of the different fragments with characteristic spectra permits to connect the pieces from various areas of an excavation to one single object or to several objects from the same batch. These results provide the archaeologist the possibility to merge recognized layers or to connect different features in the surrounding area. Secondly, we demonstrate how the use of UV-Vis-NIR spectroscopy can help improve the analysis process. This inexpensive method can facilitate a more convenient and purposive sampling by means of a preliminary inquiry, selecting the most interesting pieces out of a large group of artifacts suitable for chemical analysis.

  18. Potential application of the consistency approach for vaccine potency testing.

    Science.gov (United States)

    Arciniega, J; Sirota, L A

    2012-01-01

    The Consistency Approach offers the possibility of reducing the number of animals used for a potency test. However, it is critical to assess the effect that such reduction may have on assay performance. Consistency of production, sometimes referred to as consistency of manufacture or manufacturing, is an old concept implicit in regulation, which aims to ensure the uninterrupted release of safe and effective products. Consistency of manufacture can be described in terms of process capability, or the ability of a process to produce output within specification limits. For example, the standard method for potency testing of inactivated rabies vaccines is a multiple-dilution vaccination challenge test in mice that gives a quantitative, although highly variable estimate. On the other hand, a single-dilution test that does not give a quantitative estimate, but rather shows if the vaccine meets the specification has been proposed. This simplified test can lead to a considerable reduction in the number of animals used. However, traditional indices of process capability assume that the output population (potency values) is normally distributed, which clearly is not the case for the simplified approach. Appropriate computation of capability indices for the latter case will require special statistical considerations.

  19. Bio-optical data integration based on a 4 D database system approach

    Science.gov (United States)

    Imai, N. N.; Shimabukuro, M. H.; Carmo, A. F. C.; Alcantara, E. H.; Rodrigues, T. W. P.; Watanabe, F. S. Y.

    2015-04-01

    Bio-optical characterization of water bodies requires spatio-temporal data about Inherent Optical Properties and Apparent Optical Properties which allow the comprehension of underwater light field aiming at the development of models for monitoring water quality. Measurements are taken to represent optical properties along a column of water, and then the spectral data must be related to depth. However, the spatial positions of measurement may differ since collecting instruments vary. In addition, the records should not refer to the same wavelengths. Additional difficulty is that distinct instruments store data in different formats. A data integration approach is needed to make these large and multi source data sets suitable for analysis. Thus, it becomes possible, even automatically, semi-empirical models evaluation, preceded by preliminary tasks of quality control. In this work it is presented a solution, in the stated scenario, based on spatial - geographic - database approach with the adoption of an object relational Database Management System - DBMS - due to the possibilities to represent all data collected in the field, in conjunction with data obtained by laboratory analysis and Remote Sensing images that have been taken at the time of field data collection. This data integration approach leads to a 4D representation since that its coordinate system includes 3D spatial coordinates - planimetric and depth - and the time when each data was taken. It was adopted PostgreSQL DBMS extended by PostGIS module to provide abilities to manage spatial/geospatial data. It was developed a prototype which has the mainly tools an analyst needs to prepare the data sets for analysis.

  20. Dirac potentials in a coupled channel approach to inelastic scattering

    International Nuclear Information System (INIS)

    Mishra, V.K.; Clark, B.C.; Cooper, E.D.; Mercer, R.L.

    1990-01-01

    It has been shown that there exist transformations that can be used to change the Lorentz transformation character of potentials, which appear in the Dirac equation for elastic scattering. We consider the situation for inelastic scattering described by coupled channel Dirac equations. We examine a two-level problem where both the ground and excited states are assumed to have zero spin. Even in this simple case we have not found an appropriate transformation. However, if the excited state has zero excitation energy it is possible to find a transformation

  1. Approach to equilibrium of diffusion in a logarithmic potential.

    Science.gov (United States)

    Hirschberg, Ori; Mukamel, David; Schütz, Gunter M

    2011-10-01

    The late-time distribution function P(x,t) of a particle diffusing in a one-dimensional logarithmic potential is calculated for arbitrary initial conditions. We find a scaling solution with three surprising features: (i) the solution is given by two distinct scaling forms, corresponding to a diffusive (x∼t(1/2)) and a subdiffusive (x∼t(γ) with a given γfunction is selected by the initial condition, and (iii) depending on the tail of the initial condition, the scaling exponent that characterizes the scaling function is found to exhibit a transition from a continuously varying to a fixed value.

  2. The microscopic (optical and SEM) examination of putrefaction fluid deposits (PFD). Potential interest in forensic anthropology.

    Science.gov (United States)

    Charlier, P; Georges, P; Bouchet, F; Huynh-Charlier, I; Carlier, R; Mazel, V; Richardin, P; Brun, L; Blondiaux, J; Lorin de la Grandmaison, G

    2008-10-01

    This article describes the potential interest in physical and forensic anthropology of the microscopic analysis of residues of putrefaction fluid, a calcified deposit frequently found associated with bone rests. Its sampling and analysis seem straightforward and relatively reproducible. Samples came from archeological material (Monterenzio Vecchia, an Etruscan necropolis from the north of Italy dated between the fifth and third century B.C.; body rests of Agnès Sorel, royal mistress died in 1450 A.D.; skull and grave of French King Louis the XI and Charlotte of Savoy dated from 1483 A.D.). All samples were studied by direct optical microscope and scanning electron microscopy. Many cytological, histological, and elemental analysis were possible, producing precious data for the identification of these remains and, in some cases, the cause of death.

  3. Two-Photon Absorbing Molecules as Potential Materials for 3D Optical Memory

    Directory of Open Access Journals (Sweden)

    Kazuya Ogawa

    2014-01-01

    Full Text Available In this review, recent advances in two-photon absorbing photochromic molecules, as potential materials for 3D optical memory, are presented. The investigations introduced in this review indicate that 3D data storage processing at the molecular level is possible. As 3D memory using two-photon absorption allows advantages over existing systems, the use of two-photon absorbing photochromic molecules is preferable. Although there are some photochromic molecules with good properties for memory, in most cases, the two-photon absorption efficiency is not high. Photochromic molecules with high two-photon absorption efficiency are desired. Recently, molecules having much larger two-photon absorption cross sections over 10,000 GM (GM= 10−50 cm4 s molecule−1 photon−1 have been discovered and are expected to open the way to realize two-photon absorption 3D data storage.

  4. Energy-Dependent microscopic optical potential for p+{sup 9}Be elastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Maridi, H. M., E-mail: h.maridi@gmail.com [Physics Department, Faculty of Science, Cairo University, Giza 12613 (Egypt); Physics Department, Faculty of Applied Science, Taiz University, Taiz (Yemen); Farag, M. Y. H., E-mail: yehiafarag@cu.edu.eg; Esmael, E. H. [Physics Department, Faculty of Applied Science, Taiz University, Taiz (Yemen)

    2016-06-10

    The p+{sup 9}Be elastic scattering at an energy range up to 200 MeV/nucleon is analyzed using the single-folding model. The density- and isospin-dependent M3Y-Paris nucleon-nucleon (NN) interaction is used for the real part and the NN-scattering amplitude of the high-energy approximation for the imaginary one. The analysis reveals that the cross-section data are reproduced well at energies up to 100 MeV/nucleon by use of the partial-wave expansion. For higher energies, the eikonal approximation give results better than the partial-wave expansion calculations. The volume integrals of the optical-potential parts have systematic energy dependencies, and they are parameterized in empirical formulas.

  5. Global phenomenological optical model potential for nucleon-actinide reactions at energies up to 300 MeV

    International Nuclear Information System (INIS)

    Han Yinlu; Liang Haiying; Guo Hairui; Shen Qingbiao; Xu Yongli

    2010-01-01

    A set of new global phenomenological optical model potential parameters for the actinide region with incident nucleon energies from 1 keV up to 300 MeV is obtained. They are based on a smooth, unique functional form for the energy dependence of the potential depths and on physically constrained geometry parameters. The available experimental data including the neutron total cross sections, nonelastic cross sections, elastic scattering cross sections, elastic scattering angular distributions, and proton reaction cross sections and elastic scattering angular distributions of 232 Th and 238 U are used. The new nucleon global optical model potential parameters obtained are analyzed and used to analyze the experimental data of nucleon-actinide reactions. It is found that the present form of the global optical model potential could reproduce both the neutron and the proton experimental data.

  6. Experimental study on distributed optical fiber-based approach monitoring saturation line in levee engineering

    Science.gov (United States)

    Su, Huaizhi; Li, Hao; Kang, Yeyuan; Wen, Zhiping

    2018-02-01

    Seepage is one of key factors which affect the levee engineering safety. The seepage danger without timely detection and rapid response may likely lead to severe accidents such as seepage failure, slope instability, and even levee break. More than 90 percent of levee break events are caused by the seepage. It is very important for seepage behavior identification to determine accurately saturation line in levee engineering. Furthermore, the location of saturation line has a major impact on slope stability in levee engineering. Considering the structure characteristics and service condition of levee engineering, the distributed optical fiber sensing technology is introduced to implement the real-time observation of saturation line in levee engineering. The distributed optical fiber temperature sensor system (DTS)-based monitoring principle of saturation line in levee engineering is investigated. An experimental platform, which consists of DTS, heating system, water-supply system, auxiliary analysis system and levee model, is designed and constructed. The monitoring experiment of saturation line in levee model is implemented on this platform. According to the experimental results, the numerical relationship between moisture content and thermal conductivity in porous medium is identified. A line heat source-based distributed optical fiber method obtaining the thermal conductivity in porous medium is developed. A DTS-based approach is proposed to monitor the saturation line in levee engineering. The embedment pattern of optical fiber for monitoring saturation line is presented.

  7. A new approach to correlate transport processes and optical efficiency in GaN-based LEDs

    International Nuclear Information System (INIS)

    Pavesi, M; Manfredi, M; Rossi, F; Salviati, G; Meneghini, M; Zanoni, E

    2009-01-01

    Carrier injection and non-radiative processes are determinants of the optical efficiency of InGaN/GaN LEDs. Among transport mechanisms, tunnelling is crucial for device functioning, but other contributions can be decisive on a varying bias. It is not easy to identify the weights and roles of these terms by a simple current-voltage characterization, so it needs a careful investigation by means of complementary experimental techniques. The correlation between luminescence and microscopic transport processes in InGaN/GaN LEDs has been investigated by means of a set of techniques: electroluminescence, cathodoluminescence, current-voltage dc measurements and thermal admittance spectroscopy. Green and blue LEDs, designed with a multi-quantum-well injector layer and an optically active single-quantum-well, have been tested. They showed distinctive current and temperature dependences of the optical efficiency, with a better performance at room temperature observed for green devices. This was discussed in terms of the carrier injection efficiency controlled by electrically active traps. The comparative analysis of the optical and electrical experimental data comes in handy as a methodological approach to correlate the emission properties with the carrier injection mechanisms and to improve the functionality in a large number of quantum well heterostructures for lighting applications.

  8. Single-molecule approach to bacterial genomic comparisons via optical mapping.

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shiguo [Univ. Wisc.-Madison; Kile, A. [Univ. Wisc.-Madison; Bechner, M. [Univ. Wisc.-Madison; Kvikstad, E. [Univ. Wisc.-Madison; Deng, W. [Univ. Wisc.-Madison; Wei, J. [Univ. Wisc.-Madison; Severin, J. [Univ. Wisc.-Madison; Runnheim, R. [Univ. Wisc.-Madison; Churas, C. [Univ. Wisc.-Madison; Forrest, D. [Univ. Wisc.-Madison; Dimalanta, E. [Univ. Wisc.-Madison; Lamers, C. [Univ. Wisc.-Madison; Burland, V. [Univ. Wisc.-Madison; Blattner, F. R. [Univ. Wisc.-Madison; Schwartz, David C. [Univ. Wisc.-Madison

    2004-01-01

    Modern comparative genomics has been established, in part, by the sequencing and annotation of a broad range of microbial species. To gain further insights, new sequencing efforts are now dealing with the variety of strains or isolates that gives a species definition and range; however, this number vastly outstrips our ability to sequence them. Given the availability of a large number of microbial species, new whole genome approaches must be developed to fully leverage this information at the level of strain diversity that maximize discovery. Here, we describe how optical mapping, a single-molecule system, was used to identify and annotate chromosomal alterations between bacterial strains represented by several species. Since whole-genome optical maps are ordered restriction maps, sequenced strains of Shigella flexneri serotype 2a (2457T and 301), Yersinia pestis (CO 92 and KIM), and Escherichia coli were aligned as maps to identify regions of homology and to further characterize them as possible insertions, deletions, inversions, or translocations. Importantly, an unsequenced Shigella flexneri strain (serotype Y strain AMC[328Y]) was optically mapped and aligned with two sequenced ones to reveal one novel locus implicated in serotype conversion and several other loci containing insertion sequence elements or phage-related gene insertions. Our results suggest that genomic rearrangements and chromosomal breakpoints are readily identified and annotated against a prototypic sequenced strain by using the tools of optical mapping.

  9. Polarization Control with Plasmonic Antenna Tips: A Universal Approach to Optical Nanocrystallography and Vector-Field Imaging

    Science.gov (United States)

    Park, Kyoung-Duck; Raschke, Markus B.

    2018-05-01

    Controlling the propagation and polarization vectors in linear and nonlinear optical spectroscopy enables to probe the anisotropy of optical responses providing structural symmetry selective contrast in optical imaging. Here we present a novel tilted antenna-tip approach to control the optical vector-field by breaking the axial symmetry of the nano-probe in tip-enhanced near-field microscopy. This gives rise to a localized plasmonic antenna effect with significantly enhanced optical field vectors with control of both \\textit{in-plane} and \\textit{out-of-plane} components. We use the resulting vector-field specificity in the symmetry selective nonlinear optical response of second-harmonic generation (SHG) for a generalized approach to optical nano-crystallography and -imaging. In tip-enhanced SHG imaging of monolayer MoS$_2$ films and single-crystalline ferroelectric YMnO$_3$, we reveal nano-crystallographic details of domain boundaries and domain topology with enhanced sensitivity and nanoscale spatial resolution. The approach is applicable to any anisotropic linear and nonlinear optical response, and provides for optical nano-crystallographic imaging of molecular or quantum materials.

  10. A Stochastic Approach for Blurred Image Restoration and Optical Flow Computation on Field Image Sequence

    Institute of Scientific and Technical Information of China (English)

    高文; 陈熙霖

    1997-01-01

    The blur in target images caused by camera vibration due to robot motion or hand shaking and by object(s) moving in the background scene is different to deal with in the computer vision system.In this paper,the authors study the relation model between motion and blur in the case of object motion existing in video image sequence,and work on a practical computation algorithm for both motion analysis and blut image restoration.Combining the general optical flow and stochastic process,the paper presents and approach by which the motion velocity can be calculated from blurred images.On the other hand,the blurred image can also be restored using the obtained motion information.For solving a problem with small motion limitation on the general optical flow computation,a multiresolution optical flow algoritm based on MAP estimation is proposed. For restoring the blurred image ,an iteration algorithm and the obtained motion velocity are used.The experiment shows that the proposed approach for both motion velocity computation and blurred image restoration works well.

  11. Claus sulphur recovery potential approaches 99% while minimizing cost

    Energy Technology Data Exchange (ETDEWEB)

    Berlie, E M

    1974-01-21

    In a summary of a paper presented to the fourth joint engineering conference of the American Institute of Chemical Engineers and the Canadian Society for Chemical Engineering, the Claus process is discussed in a modern setting. Some problems faced in the operation of sulfur recovery plants include (1) strict pollution control regulations; (2) design and operation of existing plants; (3) knowledge of process fundamentals; (4) performance testing; (5) specification of feed gas; (6) catalyst life; (7) instrumentation and process control; and (8) quality of feed gas. Some of the factors which must be considered in order to achieve the ultimate capability of the Claus process are listed. There is strong evidence to support the contention that plant operators are reluctant to accept new fundamental knowledge of the Claus sulfur recovery process and are not taking advantage of its inherent potential to achieve the emission standards required, to minimize cost of tail gas cleanup systems and to minimize operating costs.

  12. Characterization of potential ionizing radiation biomarkers by a proteomic approach

    Energy Technology Data Exchange (ETDEWEB)

    Guipaud, O; Vereycken-Holler, V; Benderitter, M [Institut de Radioprotection et de Surete Nucleaire, Lab. de Radiopathologie, 92 - Fontenay aux Roses (France); Royer, N; Vinh, J [Ecole Superieure de Physique et de Chimie Industrielles, 75 - Paris (France)

    2006-07-01

    Radio-induced lesions are tissue specific, hardly predictable, and can arise months or years later. The finding of prognostic bio-markers is of fundamental relevance for the settlement of therapeutic or preventive strategies. Using two-dimensional gel electrophoresis and mass spectrometry, a proteomic study was applied to look for differentially expressed proteins, i.e. potential bio-markers candidates, in mouse serums after a local irradiation of the dorsal skin. Our results clearly indicated that serum protein content was dynamically modified after a local skin irradiation. A set of specific proteins were early down- or up-regulated and could turn out to be good candidates as diagnostic or prognostic bio-markers. (author)

  13. Characterization of potential ionizing radiation biomarkers by a proteomic approach

    International Nuclear Information System (INIS)

    Guipaud, O.; Vereycken-Holler, V.; Benderitter, M.; Royer, N.; Vinh, J.

    2006-01-01

    Radio-induced lesions are tissue specific, hardly predictable, and can arise months or years later. The finding of prognostic bio-markers is of fundamental relevance for the settlement of therapeutic or preventive strategies. Using two-dimensional gel electrophoresis and mass spectrometry, a proteomic study was applied to look for differentially expressed proteins, i.e. potential bio-markers candidates, in mouse serums after a local irradiation of the dorsal skin. Our results clearly indicated that serum protein content was dynamically modified after a local skin irradiation. A set of specific proteins were early down- or up-regulated and could turn out to be good candidates as diagnostic or prognostic bio-markers. (author)

  14. The transformative potential of an integrative approach to pregnancy.

    Science.gov (United States)

    Eidem, Haley R; McGary, Kriston L; Capra, John A; Abbot, Patrick; Rokas, Antonis

    2017-09-01

    Complex traits typically involve diverse biological pathways and are shaped by numerous genetic and environmental factors. Pregnancy-associated traits and pathologies are further complicated by extensive communication across multiple tissues in two individuals, interactions between two genomes-maternal and fetal-that obscure causal variants and lead to genetic conflict, and rapid evolution of pregnancy-associated traits across mammals and in the human lineage. Given the multi-faceted complexity of human pregnancy, integrative approaches that synthesize diverse data types and analyses harbor tremendous promise to identify the genetic architecture and environmental influences underlying pregnancy-associated traits and pathologies. We review current research that addresses the extreme complexities of traits and pathologies associated with human pregnancy. We find that successful efforts to address the many complexities of pregnancy-associated traits and pathologies often harness the power of many and diverse types of data, including genome-wide association studies, evolutionary analyses, multi-tissue transcriptomic profiles, and environmental conditions. We propose that understanding of pregnancy and its pathologies will be accelerated by computational platforms that provide easy access to integrated data and analyses. By simplifying the integration of diverse data, such platforms will provide a comprehensive synthesis that transcends many of the inherent challenges present in studies of pregnancy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Approximate approaches to the one-dimensional finite potential well

    International Nuclear Information System (INIS)

    Singh, Shilpi; Pathak, Praveen; Singh, Vijay A

    2011-01-01

    The one-dimensional finite well is a textbook problem. We propose approximate approaches to obtain the energy levels of the well. The finite well is also encountered in semiconductor heterostructures where the carrier mass inside the well (m i ) is taken to be distinct from mass outside (m o ). A relevant parameter is the mass discontinuity ratio β = m i /m o . To correctly account for the mass discontinuity, we apply the BenDaniel-Duke boundary condition. We obtain approximate solutions for two cases: when the well is shallow and when the well is deep. We compare the approximate results with the exact results and find that higher-order approximations are quite robust. For the shallow case, the approximate solution can be expressed in terms of a dimensionless parameter σ l = 2m o V 0 L 2 /ℎ 2 (or σ = β 2 σ l for the deep case). We show that the lowest-order results are related by a duality transform. We also discuss how the energy upscales with L (E∼1/L γ ) and obtain the exponent γ. Exponent γ → 2 when the well is sufficiently deep and β → 1. The ratio of the masses dictates the physics. Our presentation is pedagogical and should be useful to students on a first course on elementary quantum mechanics or low-dimensional semiconductors.

  16. Quantum teleportation and entanglement. A hybrid approach to optical quantum information procesing

    Energy Technology Data Exchange (ETDEWEB)

    Furusawa, Akira [Tokyo Univ. (Japan). Dept. of Applied Physics; Loock, Peter van [Erlangen-Nuernberg Univ. (Germany). Lehrstuhl fuer Optik

    2011-07-01

    Unique in that it is jointly written by an experimentalist and a theorist, this monograph presents universal quantum computation based on quantum teleportation as an elementary subroutine and multi-party entanglement as a universal resource. Optical approaches to measurement-based quantum computation are also described, including schemes for quantum error correction, with most of the experiments carried out by the authors themselves. Ranging from the theoretical background to the details of the experimental realization, the book describes results and advances in the field, backed by numerous illustrations of the authors' experimental setups. Aimed at researchers, physicists, and graduate and PhD students in physics, theoretical quantum optics, quantum mechanics, and quantum information. (orig.)

  17. Biofertilizers: a potential approach for sustainable agriculture development.

    Science.gov (United States)

    Mahanty, Trishna; Bhattacharjee, Surajit; Goswami, Madhurankhi; Bhattacharyya, Purnita; Das, Bannhi; Ghosh, Abhrajyoti; Tribedi, Prosun

    2017-02-01

    The worldwide increase in human population raises a big threat to the food security of each people as the land for agriculture is limited and even getting reduced with time. Therefore, it is essential that agricultural productivity should be enhanced significantly within the next few decades to meet the large demand of food by emerging population. Not to mention, too much dependence on chemical fertilizers for more crop productions inevitably damages both environmental ecology and human health with great severity. Exploitation of microbes as biofertilizers is considered to some extent an alternative to chemical fertilizers in agricultural sector due to their extensive potentiality in enhancing crop production and food safety. It has been observed that some microorganisms including plant growth promoting bacteria, fungi, Cyanobacteria, etc. have showed biofertilizer-like activities in the agricultural sector. Extensive works on biofertilizers have revealed their capability of providing required nutrients to the crop in sufficient amounts that resulted in the enhancement of crop yield. The present review elucidates various mechanisms that have been exerted by biofertilizers in order to promote plant growth and also provides protection against different plant pathogens. The aim of this review is to discuss the important roles and applications of biofertilizers in different sectors including agriculture, bioremediation, and ecology.

  18. How to actualize potential: a bioecological approach to talent development.

    Science.gov (United States)

    Ceci, Stephen J; Williams-Ceci, Sterling; Williams, Wendy M

    2016-08-01

    Bioecological theory posits three interacting principles to explain developmental outcomes such as fluctuating achievement levels and changing heritability coefficients. Here, we apply the theory to the domain of talent development, by reviewing short-term and long-term cognitive interventions. We argue that macro-level analyses of cultural practices (e.g., matrilineal inheritance and property ownership) and national systems of education are consistent with the bioecological theory; when the findings from these analyses are unpacked, the engines that drive them are so-called proximal processes. This finding has implications for the design and delivery of instruction and the development of talent. We argue that talent is fostered by the same three bioecological mechanisms that explain the actualization of genetic potential. We conclude by discussing several self-descriptions and personal narratives by gifted students in which they spontaneously refer to these bioecological mechanisms in their own talent-development processes. Similar testimonials have been documented by historic talent researchers such as Benjamin Bloom, noting the importance of continual adjustments in feedback. © 2016 New York Academy of Sciences.

  19. Deoxynivalenol, gut microbiota and immunotoxicity: A potential approach?

    Science.gov (United States)

    Liao, Yuxiao; Peng, Zhao; Chen, Liangkai; Nüssler, Andreas K; Liu, Liegang; Yang, Wei

    2018-02-01

    Deoxynivalenol (DON, vomitoxin) is the most frequent mycotoxin in grains and grain products. DON contamination in fodder and food is a serious threat for health, since it impairs the immune and gastrointestinal systems of both human and animals. Gut microbiota seems to play a more and more important part in human and animals' health according to related researches. Previous studies implied some associations among gut microbiota, DON and immune system. For example, DON affects immune system as well as the composition and abundance of gut microbiota, and the latter influences immune system as well. In the present short review, we not only provide the available information about the toxic consequences of DON-induced immunotoxicity on different animals and cell lines and discuss its main possible molecule mechanisms, but also summarize research results concerning the role of gut microbiota in DON-induced immunotoxicity and gender differences, with the aim to find some potential therapeutic strategies to tackle DON-induced immunotoxicity. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Automated Inspection of Defects in Optical Fiber Connector End Face Using Novel Morphology Approaches.

    Science.gov (United States)

    Mei, Shuang; Wang, Yudan; Wen, Guojun; Hu, Yang

    2018-05-03

    Increasing deployment of optical fiber networks and the need for reliable high bandwidth make the task of inspecting optical fiber connector end faces a crucial process that must not be neglected. Traditional end face inspections are usually performed by manual visual methods, which are low in efficiency and poor in precision for long-term industrial applications. More seriously, the inspection results cannot be quantified for subsequent analysis. Aiming at the characteristics of typical defects in the inspection process for optical fiber end faces, we propose a novel method, “difference of min-max ranking filtering” (DO2MR), for detection of region-based defects, e.g., dirt, oil, contamination, pits, and chips, and a special model, a “linear enhancement inspector” (LEI), for the detection of scratches. The DO2MR is a morphology method that intends to determine whether a pixel belongs to a defective region by comparing the difference of gray values of pixels in the neighborhood around the pixel. The LEI is also a morphology method that is designed to search for scratches at different orientations with a special linear detector. These two approaches can be easily integrated into optical inspection equipment for automatic quality verification. As far as we know, this is the first time that complete defect detection methods for optical fiber end faces are available in the literature. Experimental results demonstrate that the proposed DO2MR and LEI models yield good comprehensive performance with high precision and accepted recall rates, and the image-level detection accuracies reach 96.0 and 89.3%, respectively.

  1. Automated Inspection of Defects in Optical Fiber Connector End Face Using Novel Morphology Approaches

    Directory of Open Access Journals (Sweden)

    Shuang Mei

    2018-05-01

    Full Text Available Increasing deployment of optical fiber networks and the need for reliable high bandwidth make the task of inspecting optical fiber connector end faces a crucial process that must not be neglected. Traditional end face inspections are usually performed by manual visual methods, which are low in efficiency and poor in precision for long-term industrial applications. More seriously, the inspection results cannot be quantified for subsequent analysis. Aiming at the characteristics of typical defects in the inspection process for optical fiber end faces, we propose a novel method, “difference of min-max ranking filtering” (DO2MR, for detection of region-based defects, e.g., dirt, oil, contamination, pits, and chips, and a special model, a “linear enhancement inspector” (LEI, for the detection of scratches. The DO2MR is a morphology method that intends to determine whether a pixel belongs to a defective region by comparing the difference of gray values of pixels in the neighborhood around the pixel. The LEI is also a morphology method that is designed to search for scratches at different orientations with a special linear detector. These two approaches can be easily integrated into optical inspection equipment for automatic quality verification. As far as we know, this is the first time that complete defect detection methods for optical fiber end faces are available in the literature. Experimental results demonstrate that the proposed DO2MR and LEI models yield good comprehensive performance with high precision and accepted recall rates, and the image-level detection accuracies reach 96.0 and 89.3%, respectively.

  2. Autonomous optical navigation using nanosatellite-class instruments: a Mars approach case study

    Science.gov (United States)

    Enright, John; Jovanovic, Ilija; Kazemi, Laila; Zhang, Harry; Dzamba, Tom

    2018-02-01

    This paper examines the effectiveness of small star trackers for orbital estimation. Autonomous optical navigation has been used for some time to provide local estimates of orbital parameters during close approach to celestial bodies. These techniques have been used extensively on spacecraft dating back to the Voyager missions, but often rely on long exposures and large instrument apertures. Using a hyperbolic Mars approach as a reference mission, we present an EKF-based navigation filter suitable for nanosatellite missions. Observations of Mars and its moons allow the estimator to correct initial errors in both position and velocity. Our results show that nanosatellite-class star trackers can produce good quality navigation solutions with low position (<300 {m}) and velocity (<0.15 {m/s}) errors as the spacecraft approaches periapse.

  3. Noise study of all-normal dispersion supercontinuum sources for potential application in optical coherence tomography

    Science.gov (United States)

    Gonzalo, I. B.; Engelsholm, R. D.; Bang, O.

    2018-03-01

    Commercially available silica-fiber-based and ultra-broadband supercontinuum (SC) sources are typically generated by pumping close to the zero-dispersion wavelength (ZDW) of a photonic crystal fiber (PCF), using high-power picosecond or nanosecond laser pulses. Despite the extremely broad bandwidths, such sources are characterized by large intensity fluctuations, limiting their performance for applications in imaging such as optical coherence tomography (OCT). An approach to eliminate the influence of noise sensitive effects is to use a so-called all-normal dispersion (ANDi) fiber, in which the dispersion is normal for all the wavelengths of interest. Pumping these types of fibers with short enough femtosecond pulses allows to suppress stimulated Raman scattering (SRS), which is known to be as noisy process as modulation instability (MI), and coherent SC is generated through self-phase modulation (SPM) and optical wave breaking (OWB). In this study, we show the importance of the pump laser and fiber parameters in the design of low-noise ANDi based SC sources, for application in OCT. We numerically investigate the pulse-to-pulse fluctuations of the SC, calculating the relative intensity noise (RIN) as a function of the pump pulse duration and fiber length. Furthermore, we experimentally demonstrate the role of the fiber length on the RIN of the ANDi SC, validating the results calculated numerically. In the end, we compare the RIN of a commercial SC source based on MI and the ANDi SC source developed here, which shows better noise performance when it is carefully designed.

  4. A fortran program for elastic scattering of deuterons with an optical model containing tensorial potentials

    International Nuclear Information System (INIS)

    Raynal, J.

    1963-01-01

    The optical model has been applied with success to the elastic scattering of particles of spin 0 and 1/2 and to a lesser degree to that of deuterons. For particles of spin l/2, an LS coupling term is ordinarily used; this term is necessary to obtain a polarization; for deuterons, this coupling has been already introduced, but the possible forms of potentials are more numerous (in this case, scalar products of a second rank spin tensor with a tensor of the same rank in space or momentum can occur). These terms which may be necessary are primarily important for the tensor polarization. This problem is of particular interest at Saclay since a beam of polarized deuterons has become available. The FORTRAN program SPM 037 permits the study of the effect of tensorial potentials constructed from the distance of the deuteron from the target and its angular momentum with respect to it. This report should make possible the use and even the modification of the program. It consists of: a description of the problem and of the notation employed, a presentation of the methods adopted, an indication of the necessary data and how they should be introduced, and finally tables of symbols which are in equivalence or common statements: these tables must be considered when making any modification. (author) [fr

  5. Neutron scattering from elemental indium, the optical model, and the bound-state potential

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, S. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)); Guenther, P.T.; Lawson, R.D.; Smith, A.B. (Argonne National Lab., IL (USA))

    1990-06-01

    Neutron differential elastic-scattering cross sections of elemental indium are measured from 4.5 to 10 MeV at incident-energy intervals of {approx}500 keV. Seventy or more differential values are obtained at each incident energy, distributed between {approx}18{degree} and 160{degree}. These experimental results are combined with lower-energy values previously obtained at this laboratory, and with 11 and 14 MeV results in the literature, to form a comprehensive elastic-scattering database extending from {approx}1.5 to 14 MeV. These data are interpreted in terms of a conventional spherical optical model. The resulting potential is extrapolated to the bound-state regime. It is shown that in the middle of the 50--82 neutron shell, the potential derived from the scattering results adequately describes the binding energies of article states, but does not do well for hole states. The latter shortcoming is attributed to the holes states having occupational probabilities sufficiently different from unity, so that the exclusion principle become a factor, and to the rearrangement of the neutron core. 68 refs.

  6. Neutron scattering from elemental indium, the optical model, and the bound-state potential

    International Nuclear Information System (INIS)

    Chiba, S.; Guenther, P.T.; Lawson, R.D.; Smith, A.B.

    1990-01-01

    Neutron differential elastic-scattering cross sections of elemental indium are measured from 4.5 to 10 MeV at incident-energy intervals of ∼500 keV. Seventy or more differential values are obtained at each incident energy, distributed between ∼18 degree and 160 degree. These experimental results are combined with lower-energy values previously obtained at this laboratory, and with 11 and 14 MeV results in the literature, to form a comprehensive elastic-scattering database extending from ∼1.5 to 14 MeV. These data are interpreted in terms of a conventional spherical optical model. The resulting potential is extrapolated to the bound-state regime. It is shown that in the middle of the 50--82 neutron shell, the potential derived from the scattering results adequately describes the binding energies of article states, but does not do well for hole states. The latter shortcoming is attributed to the holes states having occupational probabilities sufficiently different from unity, so that the exclusion principle become a factor, and to the rearrangement of the neutron core. 68 refs

  7. Vibrational spectroscopic and non-linear optical activity studies on nicotinanilide : A DFT approach

    Science.gov (United States)

    Premkumar, S.; Jawahar, A.; Mathavan, T.; Dhas, M. Kumara; Benial, A. Milton Franklin

    2015-06-01

    The molecular structure of nicotinanilide was optimized by the DFT/B3LYP method with cc-pVTZ basis set using Gaussian 09 program. The first order hyperpolarizability of the molecule was calculated, which exhibits the higher nonlinear optical activity. The natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction, which leads to the higher nonlinear optical activity of the molecule. The Frontier molecular orbitals analysis of the molecule shows that the delocalization of electron density occurs within the molecule. The lower energy gap indicates that the hydrogen bond formation between the charged species. The vibrational frequencies were calculated and assigned on the basis of potential energy distribution calculation using the VEDA 4.0 program and the corresponding vibrational spectra were simulated. Hence, the nicotinanilide molecule can be a good candidate for second-order NLO material.

  8. Robust adiabatic approach to optical spin entangling in coupled quantum dots

    International Nuclear Information System (INIS)

    Gauger, Erik M; Benjamin, Simon C; Lovett, Brendon W; Nazir, Ahsan; Stace, Thomas M

    2008-01-01

    Excitonic transitions offer a possible route to ultrafast optical spin manipulation in coupled nanostructures. We perform here a detailed study of the three principal exciton-mediated decoherence channels for optically controlled electron spin qubits in coupled quantum dots: radiative decay of the excitonic state, exciton-phonon interactions, and Landau-Zener transitions between laser-dressed states. We consider a scheme for producing an entangling controlled-phase gate on a pair of coupled spins which, in its simplest dynamic form, renders the system subject to fast decoherence rates associated with exciton creation during the gating operation. In contrast, we show that an adiabatic approach employing off-resonant laser excitation allows us to suppress all sources of decoherence simultaneously, significantly increasing the fidelity of operations at only a relatively small gating time cost. We find that controlled-phase gates accurate to one part in 10 2 can realistically be achieved with the adiabatic approach, whereas the conventional dynamic approach does not appear to support a fidelity suitable for scalable quantum computation. Our predictions could be demonstrated experimentally in the near future

  9. Overlapping double potential wells in a single optical microtube cavity with vernier-scale-like tuning effect

    Energy Technology Data Exchange (ETDEWEB)

    Madani, A.; Schmidt, O. G. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, 01069 Dresden (Germany); Material Systems for Nanoelectronics, Chemnitz University of Technology, Reichenhainer Str. 70, 09107 Chemnitz (Germany); Bolaños Quiñones, V. A.; Ma, L. B., E-mail: l.ma@ifw-dresden.de; Jorgensen, M. R. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, 01069 Dresden (Germany); Miao, S. D. [Anhui Key Lab of Controllable Chemical Reaction and Material Chemical Engineering, School of Chemical Engineering, Hefei University of Technology, Tunxi Road. 193, Hefei, Anhui 230009 (China)

    2016-04-25

    Spatially and temporally overlapping double potential wells are realized in a hybrid optical microtube cavity due to the coexistence of an aggregate of luminescent quantum dots embedded in the tube wall and the cone-shaped tube's geometry. The double potential wells produce two independent sets of optical modes with different sets of mode numbers, indicating phase velocity separation for the modes overlapping at the same frequency. The overlapping mode position can be tuned by modifying the tube cavity, where these mode sets shift with different magnitudes, allowing for a vernier-scale-like tuning effect.

  10. Overlapping double potential wells in a single optical microtube cavity with vernier-scale-like tuning effect

    International Nuclear Information System (INIS)

    Madani, A.; Schmidt, O. G.; Bolaños Quiñones, V. A.; Ma, L. B.; Jorgensen, M. R.; Miao, S. D.

    2016-01-01

    Spatially and temporally overlapping double potential wells are realized in a hybrid optical microtube cavity due to the coexistence of an aggregate of luminescent quantum dots embedded in the tube wall and the cone-shaped tube's geometry. The double potential wells produce two independent sets of optical modes with different sets of mode numbers, indicating phase velocity separation for the modes overlapping at the same frequency. The overlapping mode position can be tuned by modifying the tube cavity, where these mode sets shift with different magnitudes, allowing for a vernier-scale-like tuning effect.

  11. Effect of the imaginary part of the optical potential on the reaction cross sections

    International Nuclear Information System (INIS)

    Afanas'ev, G.N.; Avramov, S.; Dobromyslev, M.B.; Kim Yng Phung; Shilov, V.M.

    It has previously been shown that in a complex potential well model of heavy ion reactions, infinitely increasing depth of the imaginary part of the potential W/sub o/ does not lead to total absorption, i.e., the Thomas model. This assertion is examined in more detail. It is first shown, by using the complex square well, that as W/sub o/ goes to infinity no total absorption occurs and the reaction cross section, after peaking at some value of W/sub o/, decreases with further increase of W/sub o/ and vanishes at W/sub o/ = infinity. Moreover, the S matrix approaches unitary limit at small and large values of W/sub o/. The second part of this paper is devoted to the construction of the ion-ion potential by folding. The real part of the ion-ion potential can be obtained in explicit form in the approximation of the constant ion densities. The potential constants can be determined by fitting the experimental binding energies

  12. Microfluidic volumetric flow determination using optical coherence tomography speckle: An autocorrelation approach

    Energy Technology Data Exchange (ETDEWEB)

    De Pretto, Lucas R., E-mail: lucas.de.pretto@usp.br; Nogueira, Gesse E. C.; Freitas, Anderson Z. [Instituto de Pesquisas Energéticas e Nucleares, IPEN–CNEN/SP, Avenida Lineu Prestes, 2242, 05508-000 São Paulo (Brazil)

    2016-04-28

    Functional modalities of Optical Coherence Tomography (OCT) based on speckle analysis are emerging in the literature. We propose a simple approach to the autocorrelation of OCT signal to enable volumetric flow rate differentiation, based on decorrelation time. Our results show that this technique could distinguish flows separated by 3 μl/min, limited by the acquisition speed of the system. We further perform a B-scan of gradient flow inside a microchannel, enabling the visualization of the drag effect on the walls.

  13. An optical potential from inversion of the 350 MeV 16 O - 16 O scattering data

    International Nuclear Information System (INIS)

    Allen, L.J.; Berge, L.; Steward, C.; Lipperheide, R.; Froebrich, P.

    1992-01-01

    A quantal inversion of the 16 O- 16 O scattering data at 350 MeV yields an optical potential which gives an excellent fit (χ 2 /F = 1.65) to the measured cross-section. The real part of this potential is shallower than any potential used by others for distances between 2 and 6 fm. The imaginary potential is also relatively weak. This potential does not favour a rainbow interpretation of the structure in data observed at large scattering angles. 12 refs., 1 tab., 4 figs

  14. Recent results in the development of a global medium-energy nucleon-nucleus optical-model potential

    International Nuclear Information System (INIS)

    Madland, D.G.

    1988-02-01

    Initial results are presented for the determination of a global medium-energy nucleon-nucleus phenomenological optical-model potential using a relativistic Schroedinger representation. The starting point for this work is the global phenomenological optical-model potential of Schwandt /ital et al./, which is based on measured elastic scattering cross sections and analyzing power for polarized protons ranging from 80 to 180 MeV. This potential is optimally modified to reproduce experimental proton reaction cross sections as a function of energy, while allowing only minimal deterioration in the fits to the elastic cross sections and analyzing powers. Further modifications in the absorptive potential were found necessary to extrapolate the modified potential to higher energies. The final potential is converted to a neutron-nucleus potential by use of standard Lane model assumptions and by accounting approximately for the Coulomb correction. Comparisons of measured and calculated proton reaction and neutron total cross sections are presented for 27 Al, 56 Fe, and 208 Pb. Medium-energy optical-model potentials for complex projectiles are briefly discussed in an appendix. 7 refs., 20 figs

  15. AN AERIAL-IMAGE DENSE MATCHING APPROACH BASED ON OPTICAL FLOW FIELD

    Directory of Open Access Journals (Sweden)

    W. Yuan

    2016-06-01

    Full Text Available Dense matching plays an important role in many fields, such as DEM (digital evaluation model producing, robot navigation and 3D environment reconstruction. Traditional approaches may meet the demand of accuracy. But the calculation time and out puts density is hardly be accepted. Focus on the matching efficiency and complex terrain surface matching feasibility an aerial image dense matching method based on optical flow field is proposed in this paper. First, some high accurate and uniformed control points are extracted by using the feature based matching method. Then the optical flow is calculated by using these control points, so as to determine the similar region between two images. Second, the optical flow field is interpolated by using the multi-level B-spline interpolation in the similar region and accomplished the pixel by pixel coarse matching. Final, the results related to the coarse matching refinement based on the combined constraint, which recognizes the same points between images. The experimental results have shown that our method can achieve per-pixel dense matching points, the matching accuracy achieves sub-pixel level, and fully meet the three-dimensional reconstruction and automatic generation of DSM-intensive matching’s requirements. The comparison experiments demonstrated that our approach’s matching efficiency is higher than semi-global matching (SGM and Patch-based multi-view stereo matching (PMVS which verifies the feasibility and effectiveness of the algorithm.

  16. The potential-free approach to the construction of the NN-wave functions

    International Nuclear Information System (INIS)

    Troitsky, V.E.

    1984-01-01

    The traditional approaches to the nonrelativistic NN-interaction use local and nonlocal potentials of the kind defined by different dynamical speculations. The wave functions are obtained then from the Schroedinger equation with the chosen potential. Here the author obtains the wave functions (scattering wave function and bound state wave function) directly from the scattering phases in the frame of a dispersion approach without use of potential. (Auth.)

  17. Interacting Effects of Leaf Water Potential and Biomass on Vegetation Optical Depth

    Science.gov (United States)

    Momen, M.; Wood, J. D.; Novick, K. A.; Pockman, W.; Konings, A. G.

    2017-12-01

    Remotely-sensed microwave observations of vegetation optical depth (VOD) have been widely used to examine vegetation responses to climate. Such studies have alternately found that VOD is sensitive to both biomass and canopy water content. However, the relative impacts of changes in phenology or water stress on VOD have not been disentangled. In particular, understanding whether leaf water potential (LWP) affects VOD may permit the assimilation of satellite observations into new large-scale plant hydraulic models. Despite extensive validation of the relationship between satellite-derived VOD estimates and vegetation density, relatively few studies have explicitly sought to validate the sensitivity of VOD to canopy water status, and none have studied the effect of variations in LWP on VOD. In this work, we test the sensitivity of VOD to variations in LWP, and present a conceptual framework which relates VOD to a combination of leaf water potential and total biomass including leaves, whose dynamics can be measured through leaf area index, and woody biomass. We used in-situ measurements of LWP data to validate the conceptual model in mixed deciduous forests in Indiana and Missouri, as well as a pinion-juniper woodland in New Mexico. Observed X-band VOD from the AMSR-E and AMSR2 satellites showed dynamics similar to those reconstructed VOD signals based on the new conceptual model which employs in-situ LWP data (R2=0.60-0.80). Because LWP data are not available at global scales, we further estimated ecosystem LWP based on remotely sensed surface soil moisture to better understand the sensitivity of VOD across ecosystems. At the global scale, incorporating a combination of biomass and water potential in the reconstructed VOD signal increased correlations with VOD about 15% compared to biomass alone and about 30% compared to water potential alone. In wetter regions with denser and taller canopy heights, VOD has a higher correlation with leaf area index than with water

  18. Optical-based molecular imaging: contrast agents and potential medical applications

    International Nuclear Information System (INIS)

    Bremer, Christoph; Ntziachristos, Vasilis; Weissleder, Ralph

    2003-01-01

    Laser- and sensitive charge-coupled device technology together with advanced mathematical modelling of photon propagation in tissue has prompted the development of novel optical imaging technologies. Fast surface-weighted imaging modalities, such as fluorescence reflectance imaging (FRI) and 3D quantitative fluorescence-mediated tomography have now become available [1, 2]. These technical advances are paralleled by a rapid development of a whole range of new optical contrasting strategies, which are designed to generate molecular contrast within a living organism. The combination of both, technical advances of light detection and the refinement of optical contrast media, finally yields a new spectrum of tools for in vivo molecular diagnostics. Whereas the technical aspects of optical imaging are covered in more detail in a previous review article in ''European Radiology'' [3], this article focuses on new developments in optical contrasting strategies and design of optical contrast agents for in vivo diagnostics. (orig.)

  19. Green approach for preparation of reduced graphene oxide decorated with gold nanoparticles and its optical and catalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Šimšíková, M., E-mail: michaela.simsikova@ceitec.vutbr.cz [CEITEC BUT, Brno University of Technology, Technická 10, 616 69 Brno (Czech Republic); Bartoš, M. [CEITEC BUT, Brno University of Technology, Technická 10, 616 69 Brno (Czech Republic); Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno (Czech Republic); Keša, P. [Department of Biochemistry, Faculty of Science, P.J. Šafárik University, Šrobárova 2, 041 54 Košice (Slovakia); Department of Biophysics, Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Košice (Slovakia); Šikola, T. [CEITEC BUT, Brno University of Technology, Technická 10, 616 69 Brno (Czech Republic); Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno (Czech Republic)

    2016-07-01

    Graphene oxide (GO) was reduced and modified by gold nanoparticles using aqueous leaf extract of green tea. Successful formation of gold nanoparticles (AuNPs) on graphene oxide surface was determined by scanning electron microscopy (SEM). Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared analyses (FT-IR) have been used to demonstrate the behavior of complex of reduced graphene oxide with gold nanoparticles (rGO-AuNPs), the removal of oxygen-containing groups from the graphene, and subsequent formation of reduced graphene oxide (rGO). We also demonstrated the change of optical properties of GO after the reduction and formation of gold nanoparticles on its surface by UV–vis spectroscopy and fluorescence spectroscopy. The positive impact of rGO-AuNPs composite on safranin T reduction in the presence of NaBH{sub 4} without light irradiation was examined, as well. The dye decolorization was observed within 60 min which highlights the exceptional catalytic potential of the rGO-AuNPs. - Highlights: • Reduction of GO was performed by an environmentally friendly approach. • Gold nanoparticles were prepared by self-assembly on the graphene oxide surface. • Surface properties were enhanced after the formation of gold nanoparticles. • Optical properties have been changed after the graphene reduction and formation of gold nanoparticles. • The decolorization of safranin T was observed within 60 min.

  20. Green approach for preparation of reduced graphene oxide decorated with gold nanoparticles and its optical and catalytic properties

    International Nuclear Information System (INIS)

    Šimšíková, M.; Bartoš, M.; Keša, P.; Šikola, T.

    2016-01-01

    Graphene oxide (GO) was reduced and modified by gold nanoparticles using aqueous leaf extract of green tea. Successful formation of gold nanoparticles (AuNPs) on graphene oxide surface was determined by scanning electron microscopy (SEM). Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared analyses (FT-IR) have been used to demonstrate the behavior of complex of reduced graphene oxide with gold nanoparticles (rGO-AuNPs), the removal of oxygen-containing groups from the graphene, and subsequent formation of reduced graphene oxide (rGO). We also demonstrated the change of optical properties of GO after the reduction and formation of gold nanoparticles on its surface by UV–vis spectroscopy and fluorescence spectroscopy. The positive impact of rGO-AuNPs composite on safranin T reduction in the presence of NaBH_4 without light irradiation was examined, as well. The dye decolorization was observed within 60 min which highlights the exceptional catalytic potential of the rGO-AuNPs. - Highlights: • Reduction of GO was performed by an environmentally friendly approach. • Gold nanoparticles were prepared by self-assembly on the graphene oxide surface. • Surface properties were enhanced after the formation of gold nanoparticles. • Optical properties have been changed after the graphene reduction and formation of gold nanoparticles. • The decolorization of safranin T was observed within 60 min.

  1. Ab Initio Optimized Effective Potentials for Real Molecules in Optical Cavities: Photon Contributions to the Molecular Ground State

    Science.gov (United States)

    2018-01-01

    We introduce a simple scheme to efficiently compute photon exchange-correlation contributions due to the coupling to transversal photons as formulated in the newly developed quantum-electrodynamical density-functional theory (QEDFT).1−5 Our construction employs the optimized-effective potential (OEP) approach by means of the Sternheimer equation to avoid the explicit calculation of unoccupied states. We demonstrate the efficiency of the scheme by applying it to an exactly solvable GaAs quantum ring model system, a single azulene molecule, and chains of sodium dimers, all located in optical cavities and described in full real space. While the first example is a two-dimensional system and allows to benchmark the employed approximations, the latter two examples demonstrate that the correlated electron-photon interaction appreciably distorts the ground-state electronic structure of a real molecule. By using this scheme, we not only construct typical electronic observables, such as the electronic ground-state density, but also illustrate how photon observables, such as the photon number, and mixed electron-photon observables, for example, electron–photon correlation functions, become accessible in a density-functional theory (DFT) framework. This work constitutes the first three-dimensional ab initio calculation within the new QEDFT formalism and thus opens up a new computational route for the ab initio study of correlated electron–photon systems in quantum cavities. PMID:29594185

  2. An efficient approach for computing the geometrical optics field reflected from a numerically specified surface

    Science.gov (United States)

    Mittra, R.; Rushdi, A.

    1979-01-01

    An approach for computing the geometrical optic fields reflected from a numerically specified surface is presented. The approach includes the step of deriving a specular point and begins with computing the reflected rays off the surface at the points where their coordinates, as well as the partial derivatives (or equivalently, the direction of the normal), are numerically specified. Then, a cluster of three adjacent rays are chosen to define a 'mean ray' and the divergence factor associated with this mean ray. Finally, the ampilitude, phase, and vector direction of the reflected field at a given observation point are derived by associating this point with the nearest mean ray and determining its position relative to such a ray.

  3. Geometrical-optics phenomena in the elastic scattering of fictitious heavy neutral nuclei by absorbing potentials

    International Nuclear Information System (INIS)

    Anni, R.; Taffara, L.

    1976-01-01

    A fictitious scattering phenomenon between neutral heavy particles is analysed by using both the square-well and trapezoidal complex potentials. After a preliminary phenomenological discussion based on the behaviour of the exact scattering matrix and the trajectories of Regge poles and zeros as continuous functions of the imaginary part of the potential, the contributions to the scattering amplitude from the external and multiple internal reflections and from the ''surface waves'' are separated by using the Debye expansion of the S(lambda)-matrix. The most important first two terms of this expansion are then compared with the exact behaviour of both the partial-wave scattering amplitude and cross-section, and the results are discussed. In particular, for potentials with large imaginary parts, the first term of the Debye expansion, which is associated with the rays directly reflected by the surface, well approximates the exact scattering matrix for all angular momenta. In these cases, by applying to this first term the Watson transformation, one is able to separate the contributions from the reflected rays (saddle-point contribution in the background integral)from that of the surface waves(surface pole contribution) which are responsible for the diffraction phenomenon. Studies are in progress in order to extend this approach to the Saxon-Wood potential with Coulomb interaction

  4. Molecular Imaging With Optical, Magnetic Resonance, and Radioisotope Techniques: Potentials and Relative Limitations

    National Research Council Canada - National Science Library

    Budinger, Thomas

    2001-01-01

    The technology advances include photodiode arrays for optical methods high field magnets proposed to 12 Tesla for functional imaging and multinuclear spectroscopy 3D ultrasound and positron tomography...

  5. Fiber optic probe enabled by surface-enhanced Raman scattering for early diagnosis of potential acute rejection of kidney transplant

    Science.gov (United States)

    Chi, Jingmao; Chen, Hui; Tolias, Peter; Du, Henry

    2014-06-01

    We have explored the use of a fiber-optic probe with surface-enhanced Raman scattering (SERS) sensing modality for early, noninvasive and, rapid diagnosis of potential renal acute rejection (AR) and other renal graft dysfunction of kidney transplant patients. Multimode silica optical fiber immobilized with colloidal Ag nanoparticles at the distal end was used for SERS measurements of as-collected urine samples at 632.8 nm excitation wavelength. All patients with abnormal renal graft function (3 AR episodes and 2 graft failure episodes) who were clinically diagnosed independently show common unique SERS spectral features in the urines collected just one day after transplant. SERS-based fiber-optic probe has excellent potential to be a bedside tool for early diagnosis of kidney transplant patients for timely medical intervention of patients at high risk of transplant dysfunction.

  6. Wide-field optical mapping of neural activity and brain haemodynamics: considerations and novel approaches

    Science.gov (United States)

    Ma, Ying; Shaik, Mohammed A.; Kozberg, Mariel G.; Thibodeaux, David N.; Zhao, Hanzhi T.; Yu, Hang

    2016-01-01

    Although modern techniques such as two-photon microscopy can now provide cellular-level three-dimensional imaging of the intact living brain, the speed and fields of view of these techniques remain limited. Conversely, two-dimensional wide-field optical mapping (WFOM), a simpler technique that uses a camera to observe large areas of the exposed cortex under visible light, can detect changes in both neural activity and haemodynamics at very high speeds. Although WFOM may not provide single-neuron or capillary-level resolution, it is an attractive and accessible approach to imaging large areas of the brain in awake, behaving mammals at speeds fast enough to observe widespread neural firing events, as well as their dynamic coupling to haemodynamics. Although such wide-field optical imaging techniques have a long history, the advent of genetically encoded fluorophores that can report neural activity with high sensitivity, as well as modern technologies such as light emitting diodes and sensitive and high-speed digital cameras have driven renewed interest in WFOM. To facilitate the wider adoption and standardization of WFOM approaches for neuroscience and neurovascular coupling research, we provide here an overview of the basic principles of WFOM, considerations for implementation of wide-field fluorescence imaging of neural activity, spectroscopic analysis and interpretation of results. This article is part of the themed issue ‘Interpreting BOLD: a dialogue between cognitive and cellular neuroscience’. PMID:27574312

  7. Wide-field optical mapping of neural activity and brain haemodynamics: considerations and novel approaches.

    Science.gov (United States)

    Ma, Ying; Shaik, Mohammed A; Kim, Sharon H; Kozberg, Mariel G; Thibodeaux, David N; Zhao, Hanzhi T; Yu, Hang; Hillman, Elizabeth M C

    2016-10-05

    Although modern techniques such as two-photon microscopy can now provide cellular-level three-dimensional imaging of the intact living brain, the speed and fields of view of these techniques remain limited. Conversely, two-dimensional wide-field optical mapping (WFOM), a simpler technique that uses a camera to observe large areas of the exposed cortex under visible light, can detect changes in both neural activity and haemodynamics at very high speeds. Although WFOM may not provide single-neuron or capillary-level resolution, it is an attractive and accessible approach to imaging large areas of the brain in awake, behaving mammals at speeds fast enough to observe widespread neural firing events, as well as their dynamic coupling to haemodynamics. Although such wide-field optical imaging techniques have a long history, the advent of genetically encoded fluorophores that can report neural activity with high sensitivity, as well as modern technologies such as light emitting diodes and sensitive and high-speed digital cameras have driven renewed interest in WFOM. To facilitate the wider adoption and standardization of WFOM approaches for neuroscience and neurovascular coupling research, we provide here an overview of the basic principles of WFOM, considerations for implementation of wide-field fluorescence imaging of neural activity, spectroscopic analysis and interpretation of results.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'. © 2016 The Authors.

  8. Facile screening of potential xenoestrogens by an estrogen receptor-based reusable optical biosensor.

    Science.gov (United States)

    Liu, Lanhua; Zhou, Xiaohong; Lu, Yun; Shan, Didi; Xu, Bi; He, Miao; Shi, Hanchang; Qian, Yi

    2017-11-15

    The apparent increase in hormone-induced cancers and disorders of the reproductive tract has led to a growing demand for new technologies capable of screening xenoestrogens. We reported an estrogen receptor (ER)-based reusable fiber biosensor for facile screening estrogenic compounds in environment. The bioassay is based on the competition of xenoestrogens with 17β-estradiol (E 2 ) for binding to the recombinant receptor of human estrogen receptor α (hERα) protein, leaving E 2 free to bind to fluorophore-labeled anti-E 2 monoclonal antibody. Unbound anti-E 2 antibody then binds to the immobilized E 2 -protein conjugate on the fiber surface, and is detected by fluorescence emission induced by evanescent field. As expected, the stronger estrogenic activity of xenoestrogen would result in the weaker fluorescent signal. Three estrogen-agonist compounds, diethylstilbestrol (DES), 4-n-nonylphenol (NP) and 4-n-octylphenol (OP), were chosen as a paradigm for validation of this assay. The rank order of estrogenic potency determined by this biosensor was DES>OP>NP, which were consistent with the published results in numerous studies. Moreover, the E 2 -protein conjugate modified optical fiber was robust enough for over 300 sensing cycles with the signal recoveries ranging from 90% to 100%. In conclusion, the biosensor is reusable, reliable, portable and amenable to on-line operation, providing a facile, efficient and economical alternative to screen potential xenoestrogens in environment. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. All-Optical Atom Trap Trace Analysis: Potential Use of 85Kr in Safeguards Activities

    International Nuclear Information System (INIS)

    Kohler, M.; Sahling, P.; Sieveke, C.; Kirchner, G.

    2015-01-01

    Sensitive measurement techniques for the detection of anthropogenic tracers demand measurement resolutions down to single atoms, as it has been demonstrated by the first atom trap trace analysis experiments. However, technical limitations had lowered the sample throughput to about 200 per year per machine. We have developed an all-optical apparatus which allows higher sample throughput and small sample sizes at the same time. Krypton-85 as anthropogenic isotope is an ideal tracer for nuclear activities since the only relevant source term is fission. An increased 85Kr concentration in an air sample indicates, that a plume was passing by during sampling. In practice, however, its applicability may be limited by the global and regional background concentrations caused by the emissions of nuclear fuel reprocessing plants. The potential of 85Kr monitoring for safeguards applications has been discussed extensively. Among these is the short range detection of elevated concentrations of 85Kr in the vicinity of reprocessing plants. Our ATTA technique needs sample sizes of about 1 l of air only and thus for the first time will allow simple environmental sampling of 85Kr with high spatial and temporal resolution. The design of such a study including local sampling and tracer transport modelling in proximity to a reprocessing plants is outlined. In addition, such a study could be used also for validating near-field atmospheric dispersion models if the 85Kr source term is known. The potential of environmental analyzes of 85Kr during an IAEA short-notice access is discussed. It is shown that it crucially depends on the emission dynamics after shut-down of fuel dissolution which needs further study. (author)

  10. The potential for optical beam shaping of UV laser sources for mass scale quarantine disinfection applications

    Science.gov (United States)

    Lizotte, Todd

    2010-08-01

    Recent events concerning H1N1 "swine flu", have demonstrated to the world the significant potential of rapid increases in death and illness among all age groups and even among the healthy population [1] when a highly infectious influenza virus is introduced. In terms of mass casualties due to a pandemic, preparedness and response planning must be done. One course of action to prevent a pandemic outbreak or reduce the impact of a bioterrorist event is the use of isolation or quarantine facilities. The first level of isolation or quarantine is within the personal residence of the person exposed or infected. In the case where, the specific virus is extremely contagious and its onset of symptoms is rapid and severe, there will be a need for the deployment and setup of larger self contained quarantine facilities. Such facilities are used to house infectious individuals to minimize the exposure of susceptible individuals to contagious individuals, especially when specialized care or treatment is required and during the viral shedding period (5 to 7 days). These types of facilities require non-shared air conditioning, heating and ventilating systems where 100% of air is vented to the outside through a series of disinfection systems and staged filters. Although chemical disinfection is possible, there is a desire to incorporate intense UV radiation as a means to deactivate and disinfect airborne virus within hospital settings and isolated mass scale quarantine facilities. UV radiation is also being considered for disinfection of contaminated surfaces, such as table tops, walls and floors in hospitals and temporary quarantine facilities. In such applications the use of UV bulb technology can create many problems, for instance bulb technology requires numerous bulbs to treat a large volume of air, generates significant heat, uses significant power and does not produce large fluxes of UV light efficiently. This paper provides several methods of creating quarantine level

  11. N-1-Alkylated Pyrimidine Films as a New Potential Optical Data Storage Medium

    DEFF Research Database (Denmark)

    Lohse, Brian; Hvilsted, Søren; Berg, Rolf Henrik

    2006-01-01

    storage. Their dimerization efficiency was compared, in solution, with uracil as a reference, and as films, to investigate the correlation between solution and film. Films of good quality displaying excellent thermal and optical stability can be fabricated. A significant optical contrast between...... grating storage are also demonstrated in the films. Writing and reading of the gray scale can be performed at the same wavelength....

  12. Thermally induced passage and current of particles in a highly unstable optical potential

    Czech Academy of Sciences Publication Activity Database

    Ryabov, A.; Zemánek, Pavel; Filip, R.

    2016-01-01

    Roč. 94, č. 4 (2016), 042108:1-9 ISSN 2470-0045 R&D Projects: GA ČR GB14-36681G Institutional support: RVO:68081731 Keywords : Brownian movement * Electron transitions * Optical tweezers Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.366, year: 2016

  13. Diagnostic potential of iris cross-sectional imaging in albinism using optical coherence tomography.

    Science.gov (United States)

    Sheth, Viral; Gottlob, Irene; Mohammad, Sarim; McLean, Rebecca J; Maconachie, Gail D E; Kumar, Anil; Degg, Christopher; Proudlock, Frank A

    2013-10-01

    To characterize in vivo anatomic abnormalities of the iris in albinism compared with healthy controls using anterior segment optical coherence tomography (AS-OCT) and to explore the diagnostic potential of this technique for albinism. We also investigated the relationship between iris abnormalities and other phenotypical features of albinism. Prospective cross-sectional study. A total of 55 individuals with albinism and 45 healthy controls. We acquired 4.37×4.37-mm volumetric scans (743 A-scans, 50 B-scans) of the nasal and temporal iris in both eyes using AS-OCT (3-μm axial resolution). Iris layers were segmented and thicknesses were measured using ImageJ software. Iris transillumination grading was graded using Summers and colleagues' classification. Retinal OCT, eye movement recordings, best-corrected visual acuity (BCVA), visual evoked potential (VEP), and grading of skin and hair pigmentation were used to quantify other phenotypical features associated with albinism. Iris AS-OCT measurements included (1) total iris thickness, (2) stroma/anterior border (SAB) layer thickness, and (3) posterior epithelial layer (PEL) thickness. Correlation with other phenotypical measurements, including (1) iris transillumination grading, (2) retinal layer measurements at the fovea, (3) nystagmus intensity, (4) BCVA, (5) VEP asymmetry, (6) skin pigmentation, and (7) hair pigmentation (of head hair, lashes, and brows). The mean iris thickness was 10.7% thicker in controls (379.3 ± 44.0 μm) compared with the albinism group (342.5 ± 52.6 μm; P>0.001), SAB layers were 5.8% thicker in controls (315.1 ± 43.8 μm) compared with the albinism group (297.7 ± 50.0 μm; P=0.044), and PEL was 44.0% thicker in controls (64.1 ± 11.7 μm) compared with the albinism group (44.5 ± 13.9 μm; Palbinism. Phenotypic features of albinism, such as skin and hair pigmentation, BCVA, and nystagmus intensity, were significantly correlated to AS-OCT iris thickness measurements. We have

  14. Parity-even and time-reversal-odd neutron optical potential in spinning matter induced by gravitational torsion

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, A.N., E-mail: ivanov@kph.tuwien.ac.at [Atominstitut, Technische Universität Wien, Stadionallee 2, A-1020 Wien (Austria); Snow, W.M., E-mail: wsnow@indiana.edu [Indiana University, Bloomington, IN 47408 (United States); Center for Exploration of Energy and Matter, Indiana University, Bloomington, IN 47408 (United States)

    2017-01-10

    Recent theoretical work has shown that spin 1/2 particles moving through unpolarized matter which sources torsion fields experience a new type of parity-even and time-reversal-odd optical potential if the matter is spinning in the lab frame. This new type of optical potential can be sought experimentally using the helicity dependence of the total cross sections for longitudinally polarized neutrons moving through a rotating cylindrical target. In combination with recent experimental constraints on short-range P-odd, T-even torsion interactions derived from polarized neutron spin rotation in matter one can derive separate constraints on the time components of scalar and pseudoscalar torsion fields in matter. We estimate the sensitivity achievable in such an experiment and briefly outline some of the potential sources of systematic error to be considered in any future experimental search for this effect.

  15. Parity-even and time-reversal-odd neutron optical potential in spinning matter induced by gravitational torsion

    Directory of Open Access Journals (Sweden)

    A.N. Ivanov

    2017-01-01

    Full Text Available Recent theoretical work has shown that spin 1/2 particles moving through unpolarized matter which sources torsion fields experience a new type of parity-even and time-reversal-odd optical potential if the matter is spinning in the lab frame. This new type of optical potential can be sought experimentally using the helicity dependence of the total cross sections for longitudinally polarized neutrons moving through a rotating cylindrical target. In combination with recent experimental constraints on short-range P-odd, T-even torsion interactions derived from polarized neutron spin rotation in matter one can derive separate constraints on the time components of scalar and pseudoscalar torsion fields in matter. We estimate the sensitivity achievable in such an experiment and briefly outline some of the potential sources of systematic error to be considered in any future experimental search for this effect.

  16. Expansion of a Bose-Einstein condensate formed on a joint harmonic and one-dimensional optical-lattice potential

    International Nuclear Information System (INIS)

    Adhikari, Sadhan K

    2003-01-01

    We study the expansion of a Bose-Einstein condensate trapped in a combined optical-lattice and axially-symmetric harmonic potential using the numerical solution of the mean-field Gross-Pitaevskii equation. First, we consider the expansion of such a condensate under the action of the optical-lattice potential alone. In this case the result of numerical simulation for the axial and radial sizes during expansion is in agreement with two experiments by Morsch et al (2002 Phys. Rev. A 66 021601(R) and 2003 Laser Phys. 13 594). Finally, we consider the expansion under the action of the harmonic potential alone. In this case the oscillation, and the disappearance and revival of the resultant interference pattern is in agreement with the experiment by Mueller et al (2003 J. Opt. B: Quantum Semiclass. Opt. 5 S38)

  17. Highly curved image sensors: a practical approach for improved optical performance.

    Science.gov (United States)

    Guenter, Brian; Joshi, Neel; Stoakley, Richard; Keefe, Andrew; Geary, Kevin; Freeman, Ryan; Hundley, Jake; Patterson, Pamela; Hammon, David; Herrera, Guillermo; Sherman, Elena; Nowak, Andrew; Schubert, Randall; Brewer, Peter; Yang, Louis; Mott, Russell; McKnight, Geoff

    2017-06-12

    The significant optical and size benefits of using a curved focal surface for imaging systems have been well studied yet never brought to market for lack of a high-quality, mass-producible, curved image sensor. In this work we demonstrate that commercial silicon CMOS image sensors can be thinned and formed into accurate, highly curved optical surfaces with undiminished functionality. Our key development is a pneumatic forming process that avoids rigid mechanical constraints and suppresses wrinkling instabilities. A combination of forming-mold design, pressure membrane elastic properties, and controlled friction forces enables us to gradually contact the die at the corners and smoothly press the sensor into a spherical shape. Allowing the die to slide into the concave target shape enables a threefold increase in the spherical curvature over prior approaches having mechanical constraints that resist deformation, and create a high-stress, stretch-dominated state. Our process creates a bridge between the high precision and low-cost but planar CMOS process, and ideal non-planar component shapes such as spherical imagers for improved optical systems. We demonstrate these curved sensors in prototype cameras with custom lenses, measuring exceptional resolution of 3220 line-widths per picture height at an aperture of f/1.2 and nearly 100% relative illumination across the field. Though we use a 1/2.3" format image sensor in this report, we also show this process is generally compatible with many state of the art imaging sensor formats. By example, we report photogrammetry test data for an APS-C sized silicon die formed to a 30° subtended spherical angle. These gains in sharpness and relative illumination enable a new generation of ultra-high performance, manufacturable, digital imaging systems for scientific, industrial, and artistic use.

  18. Exciton scattering approach for optical spectra calculations in branched conjugated macromolecules

    International Nuclear Information System (INIS)

    Li, Hao; Wu, Chao; Malinin, Sergey V.; Tretiak, Sergei; Chernyak, Vladimir Y.

    2016-01-01

    The exciton scattering (ES) technique is a multiscale approach based on the concept of a particle in a box and developed for efficient calculations of excited-state electronic structure and optical spectra in low-dimensional conjugated macromolecules. Within the ES method, electronic excitations in molecular structure are attributed to standing waves representing quantum quasi-particles (excitons), which reside on the graph whose edges and nodes stand for the molecular linear segments and vertices, respectively. Exciton propagation on the linear segments is characterized by the exciton dispersion, whereas exciton scattering at the branching centers is determined by the energy-dependent scattering matrices. Using these ES energetic parameters, the excitation energies are then found by solving a set of generalized “particle in a box” problems on the graph that represents the molecule. Similarly, unique energy-dependent ES dipolar parameters permit calculations of the corresponding oscillator strengths, thus, completing optical spectra modeling. Both the energetic and dipolar parameters can be extracted from quantum-chemical computations in small molecular fragments and tabulated in the ES library for further applications. Subsequently, spectroscopic modeling for any macrostructure within a considered molecular family could be performed with negligible numerical effort. We demonstrate the ES method application to molecular families of branched conjugated phenylacetylenes and ladder poly-para-phenylenes, as well as structures with electron donor and acceptor chemical substituents. Time-dependent density functional theory (TD-DFT) is used as a reference model for electronic structure. The ES calculations accurately reproduce the optical spectra compared to the reference quantum chemistry results, and make possible to predict spectra of complex macromolecules, where conventional electronic structure calculations are unfeasible.

  19. Exciton scattering approach for optical spectra calculations in branched conjugated macromolecules

    Science.gov (United States)

    Li, Hao; Wu, Chao; Malinin, Sergey V.; Tretiak, Sergei; Chernyak, Vladimir Y.

    2016-12-01

    The exciton scattering (ES) technique is a multiscale approach based on the concept of a particle in a box and developed for efficient calculations of excited-state electronic structure and optical spectra in low-dimensional conjugated macromolecules. Within the ES method, electronic excitations in molecular structure are attributed to standing waves representing quantum quasi-particles (excitons), which reside on the graph whose edges and nodes stand for the molecular linear segments and vertices, respectively. Exciton propagation on the linear segments is characterized by the exciton dispersion, whereas exciton scattering at the branching centers is determined by the energy-dependent scattering matrices. Using these ES energetic parameters, the excitation energies are then found by solving a set of generalized "particle in a box" problems on the graph that represents the molecule. Similarly, unique energy-dependent ES dipolar parameters permit calculations of the corresponding oscillator strengths, thus, completing optical spectra modeling. Both the energetic and dipolar parameters can be extracted from quantum-chemical computations in small molecular fragments and tabulated in the ES library for further applications. Subsequently, spectroscopic modeling for any macrostructure within a considered molecular family could be performed with negligible numerical effort. We demonstrate the ES method application to molecular families of branched conjugated phenylacetylenes and ladder poly-para-phenylenes, as well as structures with electron donor and acceptor chemical substituents. Time-dependent density functional theory (TD-DFT) is used as a reference model for electronic structure. The ES calculations accurately reproduce the optical spectra compared to the reference quantum chemistry results, and make possible to predict spectra of complex macromolecules, where conventional electronic structure calculations are unfeasible.

  20. Exciton scattering approach for optical spectra calculations in branched conjugated macromolecules

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hao [Department of Chemistry, University of Houston, Houston, TX 77204 (United States); Wu, Chao [Electronic Structure Lab, Center of Microscopic Theory and Simulation, Frontier Institute of Science and Technology, Xian Jiaotong University, Xian 710054 (China); Malinin, Sergey V. [Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202 (United States); Tretiak, Sergei, E-mail: serg@lanl.gov [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Chernyak, Vladimir Y., E-mail: chernyak@chem.wayne.edu [Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202 (United States)

    2016-12-20

    The exciton scattering (ES) technique is a multiscale approach based on the concept of a particle in a box and developed for efficient calculations of excited-state electronic structure and optical spectra in low-dimensional conjugated macromolecules. Within the ES method, electronic excitations in molecular structure are attributed to standing waves representing quantum quasi-particles (excitons), which reside on the graph whose edges and nodes stand for the molecular linear segments and vertices, respectively. Exciton propagation on the linear segments is characterized by the exciton dispersion, whereas exciton scattering at the branching centers is determined by the energy-dependent scattering matrices. Using these ES energetic parameters, the excitation energies are then found by solving a set of generalized “particle in a box” problems on the graph that represents the molecule. Similarly, unique energy-dependent ES dipolar parameters permit calculations of the corresponding oscillator strengths, thus, completing optical spectra modeling. Both the energetic and dipolar parameters can be extracted from quantum-chemical computations in small molecular fragments and tabulated in the ES library for further applications. Subsequently, spectroscopic modeling for any macrostructure within a considered molecular family could be performed with negligible numerical effort. We demonstrate the ES method application to molecular families of branched conjugated phenylacetylenes and ladder poly-para-phenylenes, as well as structures with electron donor and acceptor chemical substituents. Time-dependent density functional theory (TD-DFT) is used as a reference model for electronic structure. The ES calculations accurately reproduce the optical spectra compared to the reference quantum chemistry results, and make possible to predict spectra of complex macromolecules, where conventional electronic structure calculations are unfeasible.

  1. Differential elastic scattering of He* (21S) by Ar, Kr and Xe: Repulsive rainbows and optical potentials

    International Nuclear Information System (INIS)

    Martin, D.W.; Gregor, R.W.; Jordan, R.M.; Siska, P.E.

    1978-01-01

    Elastic scattering angular distributions of He* (2 1 S) with Ar, Kr, and Xe measured in crossed atomic beams at collision energies from 0.4--2.8 kcal/mole are analyzed using a physically motivated optical potential model. The resulting potentials show some features expected on the basis of the analogous Li--rare gas potentials: monotonically increasing van der Waals well depths epsilon in the sequence Ar, Kr, Xe, and nearly constant well position r/sub m/. However, structure occurs in the repulsive parts of the potentials in the form of a local slope maximum (force minimum) at low positive potential energy, as suggested by other studies. The potential energy at the slope maximum decreases monotonically in the Ar, Kr, Xe sequence, while its position increases monotonically. The slope maximum is manifested in the angular distributions through the appearance of rainbow scattering peaks for Ar and Kr at angles well removed from those at which attractive rainbows are expected, with both repulsive and attractive rainbows evident in the same distribution. The resonance widths are constrained to be simple exponentials. Table I contains all potential parameters derived. Reasonably good agreement is obtained between measured total ionization cross sections and quenching rate constants and those calculated from the optical potentials

  2. Analysis of optically variable devices using a photometric light-field approach

    Science.gov (United States)

    Soukup, Daniel; Å tolc, Svorad; Huber-Mörk, Reinhold

    2015-03-01

    Diffractive Optically Variable Image Devices (DOVIDs), sometimes loosely referred to as holograms, are popular security features for protecting banknotes, ID cards, or other security documents. Inspection, authentication, as well as forensic analysis of these security features are still demanding tasks requiring special hardware tools and expert knowledge. Existing equipment for such analyses is based either on a microscopic analysis of the grating structure or a point-wise projection and recording of the diffraction patterns. We investigated approaches for an examination of DOVID security features based on sampling the Bidirectional Reflectance Distribution Function (BRDF) of DOVIDs using photometric stereo- and light-field-based methods. Our approach is demonstrated on the practical task of automated discrimination between genuine and counterfeited DOVIDs on banknotes. For this purpose, we propose a tailored feature descriptor which is robust against several expected sources of inaccuracy but still specific enough for the given task. The suggested approach is analyzed from both theoretical as well as practical viewpoints and w.r.t. analysis based on photometric stereo and light fields. We show that especially the photometric method provides a reliable and robust tool for revealing DOVID behavior and authenticity.

  3. Generalization of the geometric optical series approach for nonadiabatic scattering problems

    International Nuclear Information System (INIS)

    Herman, M.F.

    1982-01-01

    The geometric optical series approach of Bremmer is generalized for multisurface nonadiabatic scattering problems. This method yields the formal solution of the Schroedinger equation as an infinite series of multiple integrals. The zeroth order term corresponds to WKB propagation on a single adiabatic surface, while the general Nth order term involves N reflections and/or transitions between surfaces accompanied by ''free,'' single surface semiclassical propagation between the points of reflection and transition. Each term is integrated over all possible transition and reflection points. The adiabatic and diabatic limits of this expression are discussed. Numerical results, in which all reflections are ignored, are presented for curve crossing and noncrossing problems. These results are compared to exact quantum results and are shown to be highly accurate

  4. A variational approach to bag formation and the quark-antiquark potential

    International Nuclear Information System (INIS)

    Akiba, T.; Takagi, F.

    1983-01-01

    A variational approach is used to the Adler problem which is to obtain the color confinement region and the q-anti q static potential from approxiamte effective potentials of quantum chromodynamics. It yields fairly good fits to the Adler-Piran numerical results. (orig.)

  5. Monitoring Ingress of Moisture in Structural Concrete Using a Novel Optical-Based Sensor Approach

    International Nuclear Information System (INIS)

    Yeo, T L; Cox, M A C; Boswell, L F; Sun, T; Grattan, K T V

    2006-01-01

    The detection of moisture ingress in concrete is important for structural monitoring and in this work is realised by monitoring the shift in the characteristic wavelength of a fibre Bragg grating-based sensor. The sensor relies upon a moisture-sensitive polymer layer deposited on the fibre Bragg grating (FBG) and the strain induced on it as a result of polymer swelling is monitored. Moisture ingress experiments were carried out using two such optical fibre sensors, placed at varying distances from the edge of the face of standard concrete cubes to the inner part of the concrete sample and subjected to water at a constant temperature. Information on the properties of different types of concrete and thus potentially on the migration of dissolved salts and their effect on reinforcement bars within concrete can be obtained

  6. Postsynaptic potentials recorded in neurons of the cat's lateral geniculate nucleus following electrical stimulation of the optic chiasm.

    Science.gov (United States)

    Bloomfield, S A; Sherman, S M

    1988-12-01

    1. We recorded intracellularly from X and Y cells of the cat's lateral geniculate nucleus and measured the postsynaptic potentials (PSPs) evoked from electrical stimulation of the optic chiasm. We used an in vivo preparation and computer averaged the PSPs to enhance their signal-to-noise ratio. 2. The vast majority (46 of 50) of our sample of X and Y cells responded to stimulation of the optic chiasm with an excitatory postsynaptic potential (EPSP) followed by an inhibitory postsynaptic potential (IPSP); these were tentatively identified as relay cells. We quantified several parameters of these PSPs, including amplitude, latency, time to peak (i.e., rise time), and duration. 3. Among the relay cells, the latencies of both the EPSP and action potential evoked by optic chiasm stimulation were shorter in Y cells than in X cells. Furthermore, the difference between the latencies of the EPSP and action potential was shorter for Y cells than for X cells. This means that the EPSPs generated in Y cells reached threshold for generation of action potentials faster than did those in X cells. The EPSPs of Y cells also displayed larger amplitudes and faster rise times than did those in X cells, but neither of these distinctions was sufficient to explain the shorter latency difference between the EPSP and action potential for Y cells. 4. The EPSPs recorded in relay Y cells had longer durations than did those in relay X cells. Our data suggest that the subsequent IPSP actively terminates the EPSP, which, in turn, suggests that the time interval between EPSP and IPSP onsets is longer in Y cells than in X cells. Furthermore, we found that, for individual Y cells, the latency and duration of the evoked EPSP were inversely related. These observations lead to the conclusion that the latency of IPSPs activated from the optic chiasm is relatively constant among Y cells and thus independent of the EPSP latencies. Thus the excitation and inhibition produced in individual geniculate Y

  7. Energy dependence of the optical potential of weakly and tightly bound nuclei as projectiles on a medium-mass target

    International Nuclear Information System (INIS)

    Figueira, J. M.; Arazi, A.; Carnelli, P.; Heimann, D. Martinez; Negri, A. E.; Pacheco, A. J.; Niello, J. O. Fernandez; Capurro, O. A.; Fimiani, L.; Marti, G. V.; Lubian, J.; Monteiro, D. S.; Gomes, P. R. S.

    2010-01-01

    Angular distributions for the elastic scattering of the weakly bound 6,7 Li+ 144 Sm systems were measured with high accuracy at bombarding energies from 85% up to 170% of the Coulomb barrier. An optical model analysis was performed, and the relevant parameters of the real and imaginary parts of the optical potential were extracted. The results are compared with those previously published for the tightly bound 12 C+ 144 Sm and 16 O+ 144 Sm systems. The usual threshold anomaly observed in the behavior of the potential of tightly bound systems was not observed for either weakly bound system. This absence is attributed to the repulsion due to breakup coupling which cancels the attraction arising from couplings with bound channels.

  8. Dual Optical Recordings for Action Potentials and Calcium Handling in Induced Pluripotent Stem Cell Models of Cardiac Arrhythmias Using Genetically Encoded Fluorescent Indicators

    Science.gov (United States)

    Song, LouJin; Awari, Daniel W.; Han, Elizabeth Y.; Uche-Anya, Eugenia; Park, Seon-Hye E.; Yabe, Yoko A.; Chung, Wendy K.

    2015-01-01

    Reprogramming of human somatic cells to pluripotency has been used to investigate disease mechanisms and to identify potential therapeutics. However, the methods used for reprogramming, in vitro differentiation, and phenotyping are still complicated, expensive, and time-consuming. To address the limitations, we first optimized a protocol for reprogramming of human fibroblasts and keratinocytes into pluripotency using single lipofection and the episomal vectors in a 24-well plate format. This method allowed us to generate multiple lines of integration-free and feeder-free induced pluripotent stem cells (iPSCs) from seven patients with cardiac diseases and three controls. Second, we differentiated human iPSCs derived from patients with Timothy syndrome into cardiomyocytes using a monolayer differentiation method. We found that Timothy syndrome cardiomyocytes showed slower, irregular contractions and abnormal calcium handling compared with the controls. The results are consistent with previous reports using a retroviral method for reprogramming and an embryoid body-based method for cardiac differentiation. Third, we developed an efficient approach for recording the action potentials and calcium transients simultaneously in control and patient cardiomyocytes using genetically encoded fluorescent indicators, ArcLight and R-GECO1. The dual optical recordings enabled us to observe prolonged action potentials and abnormal calcium handling in Timothy syndrome cardiomyocytes. We confirmed that roscovitine rescued the phenotypes in Timothy syndrome cardiomyocytes and that these findings were consistent with previous studies using conventional electrophysiological recordings and calcium imaging with dyes. The approaches using our optimized methods and dual optical recordings will improve iPSC applicability for disease modeling to investigate mechanisms underlying cardiac arrhythmias and to test potential therapeutics. PMID:25769651

  9. Intercomparison of the GOS approach, superposition T-matrix method, and laboratory measurements for black carbon optical properties during aging

    International Nuclear Information System (INIS)

    He, Cenlin; Takano, Yoshi; Liou, Kuo-Nan; Yang, Ping; Li, Qinbin; Mackowski, Daniel W.

    2016-01-01

    We perform a comprehensive intercomparison of the geometric-optics surface-wave (GOS) approach, the superposition T-matrix method, and laboratory measurements for optical properties of fresh and coated/aged black carbon (BC) particles with complex structures. GOS and T-matrix calculations capture the measured optical (i.e., extinction, absorption, and scattering) cross sections of fresh BC aggregates, with 5–20% differences depending on particle size. We find that the T-matrix results tend to be lower than the measurements, due to uncertainty in theoretical approximations of realistic BC structures, particle property measurements, and numerical computations in the method. On the contrary, the GOS results are higher than the measurements (hence the T-matrix results) for BC radii 100 nm. We find good agreement (differences 100 nm. We find small deviations (≤10%) in asymmetry factors computed from the two methods for most BC coating structures and sizes, but several complex structures have 10–30% differences. This study provides the foundation for downstream application of the GOS approach in radiative transfer and climate studies. - Highlights: • The GOS and T-matrix methods capture laboratory measurements of BC optical properties. • The GOS results are consistent with the T-matrix results for BC optical properties. • BC optical properties vary remarkably with coating structures and sizes during aging.

  10. Towards breaking the spatial resolution barriers: An optical flow and super-resolution approach for sea ice motion estimation

    Science.gov (United States)

    Petrou, Zisis I.; Xian, Yang; Tian, YingLi

    2018-04-01

    Estimation of sea ice motion at fine scales is important for a number of regional and local level applications, including modeling of sea ice distribution, ocean-atmosphere and climate dynamics, as well as safe navigation and sea operations. In this study, we propose an optical flow and super-resolution approach to accurately estimate motion from remote sensing images at a higher spatial resolution than the original data. First, an external example learning-based super-resolution method is applied on the original images to generate higher resolution versions. Then, an optical flow approach is applied on the higher resolution images, identifying sparse correspondences and interpolating them to extract a dense motion vector field with continuous values and subpixel accuracies. Our proposed approach is successfully evaluated on passive microwave, optical, and Synthetic Aperture Radar data, proving appropriate for multi-sensor applications and different spatial resolutions. The approach estimates motion with similar or higher accuracy than the original data, while increasing the spatial resolution of up to eight times. In addition, the adopted optical flow component outperforms a state-of-the-art pattern matching method. Overall, the proposed approach results in accurate motion vectors with unprecedented spatial resolutions of up to 1.5 km for passive microwave data covering the entire Arctic and 20 m for radar data, and proves promising for numerous scientific and operational applications.

  11. A catalytic approach to estimate the redox potential of heme-peroxidases

    International Nuclear Information System (INIS)

    Ayala, Marcela; Roman, Rosa; Vazquez-Duhalt, Rafael

    2007-01-01

    The redox potential of heme-peroxidases varies according to a combination of structural components within the active site and its vicinities. For each peroxidase, this redox potential imposes a thermodynamic threshold to the range of oxidizable substrates. However, the instability of enzymatic intermediates during the catalytic cycle precludes the use of direct voltammetry to measure the redox potential of most peroxidases. Here we describe a novel approach to estimate the redox potential of peroxidases, which directly depends on the catalytic performance of the activated enzyme. Selected p-substituted phenols are used as substrates for the estimations. The results obtained with this catalytic approach correlate well with the oxidative capacity predicted by the redox potential of the Fe(III)/Fe(II) couple

  12. Approaches to defining «financial potential» concept as of economic analysis object

    Directory of Open Access Journals (Sweden)

    O.M. Dzyubenkо

    2017-12-01

    Full Text Available The research analyzes the works of scientists who studied the issues of financial potential as an economic category. Due to analyzing the approaches of the scientists to the concept of "financial potential" the author identifies six approaches to the interpretation of its essence, they are: the totality of the enterprise financial resources, the sources of the enterprise economic activity financing, the enterprise economic activity development, the enterprise financial indicators, the system of enterprise financial management, the enterprise efficiency characteristics. It is established that the financial potential is the multifaceted category that characterizes the financial and economic activity of enterprises. The author's definition of the financial potential in the context of its place in the objects of economic analysis is proposed. It is established that the financial potential is the object of the enterprise economic activity management and is the subject to analytical assessments for establishing its state and directions of development.

  13. Neutron penetrabilities using an optical model potential (1963); Penetrabilites des neutrons selon le modele du potentiel optique (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Mani, G S; Melkanoff, M A; Iori, I [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    The neutron penetrabilities and reaction cross-sections are presented in these tables for the case of an optical model potential for the nucleus, for nuclei up to mass 230. (authors) [French] Les penetrabilites et les sections efficaces de reaction pour les neutrons sont donnees dans ces tables en utilisant le modele du potentiel optique, pour les noyaux cibles jusqu'a la masse 230. (auteurs)

  14. Neutron penetrabilities using an optical model potential (1963); Penetrabilites des neutrons selon le modele du potentiel optique (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Mani, G.S.; Melkanoff, M.A.; Iori, I. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    The neutron penetrabilities and reaction cross-sections are presented in these tables for the case of an optical model potential for the nucleus, for nuclei up to mass 230. (authors) [French] Les penetrabilites et les sections efficaces de reaction pour les neutrons sont donnees dans ces tables en utilisant le modele du potentiel optique, pour les noyaux cibles jusqu'a la masse 230. (auteurs)

  15. Novel approach for all-optical packet switching in wide-area networks

    Science.gov (United States)

    Chlamtac, Imrich; Fumagalli, Andrea F.; Wedzinga, Gosse

    1998-09-01

    All-optical Wavelength Division Multiplexing (WDM) networks are believed to be a fundamental component in future high speed backbones. However, while wavelength routing made circuit switching in WDM feasible the reality of extant optical technology does not yet provide the necessary devices to achieve individual optical packet switching. This paper proposes to achieve all-optical packet switching in WDM Wide Area Networks (WANs) via a novel technique, called slot routing. Using slot routing, entire slots, each carrying multiple packets on distinct wavelengths, are switched transparently and individually. As a result packets can be optically transmitted and switched in the network using available fast and wavelength non-sensitive devices. The proposed routing technique leads to an optical packet switching solution, that is simple, practical, and unique as it makes it possible to build a WDM all-optical WAN with optical devices based on proven technologies.

  16. Dual resonance approach to optical signal processing beyond the carrier relaxation rate

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Kristensen, Philip Trøst; Mørk, Jesper

    2014-01-01

    We propose using two optical cavities in a differential control scheme to increase the bandwidth of cavity-based semiconductor optical signal processing devices beyond the limit given by the slowest carrier relaxation rate of the medium.......We propose using two optical cavities in a differential control scheme to increase the bandwidth of cavity-based semiconductor optical signal processing devices beyond the limit given by the slowest carrier relaxation rate of the medium....

  17. Semiclassical approach to Regge poles trajectories calculations for nonsingular potentials: Thomas-Fermi type

    International Nuclear Information System (INIS)

    Belov, S M; Avdonina, N B; Felfli, Z; Marletta, M; Msezane, A Z; Naboko, S N

    2004-01-01

    A simple semiclassical approach, based on the investigation of anti-Stokes line topology, is presented for calculating Regge poles for nonsingular (Thomas-Fermi type) potentials, namely potentials with singularities at the origin weaker than order -2. The anti-Stokes lines for Thomas-Fermi potentials have a more complicated structure than those of singular potentials and require careful application of complex analysis. The explicit solution of the Bohr-Sommerfeld quantization condition is used to obtain approximate Regge poles. We introduce and employ three hypotheses to obtain several terms of the Regge pole approximation

  18. Raman fiber-optical method for colon cancer detection: Cross-validation and outlier identification approach

    Science.gov (United States)

    Petersen, D.; Naveed, P.; Ragheb, A.; Niedieker, D.; El-Mashtoly, S. F.; Brechmann, T.; Kötting, C.; Schmiegel, W. H.; Freier, E.; Pox, C.; Gerwert, K.

    2017-06-01

    Endoscopy plays a major role in early recognition of cancer which is not externally accessible and therewith in increasing the survival rate. Raman spectroscopic fiber-optical approaches can help to decrease the impact on the patient, increase objectivity in tissue characterization, reduce expenses and provide a significant time advantage in endoscopy. In gastroenterology an early recognition of malign and precursor lesions is relevant. Instantaneous and precise differentiation between adenomas as precursor lesions for cancer and hyperplastic polyps on the one hand and between high and low-risk alterations on the other hand is important. Raman fiber-optical measurements of colon biopsy samples taken during colonoscopy were carried out during a clinical study, and samples of adenocarcinoma (22), tubular adenomas (141), hyperplastic polyps (79) and normal tissue (101) from 151 patients were analyzed. This allows us to focus on the bioinformatic analysis and to set stage for Raman endoscopic measurements. Since spectral differences between normal and cancerous biopsy samples are small, special care has to be taken in data analysis. Using a leave-one-patient-out cross-validation scheme, three different outlier identification methods were investigated to decrease the influence of systematic errors, like a residual risk in misplacement of the sample and spectral dilution of marker bands (esp. cancerous tissue) and therewith optimize the experimental design. Furthermore other validations methods like leave-one-sample-out and leave-one-spectrum-out cross-validation schemes were compared with leave-one-patient-out cross-validation. High-risk lesions were differentiated from low-risk lesions with a sensitivity of 79%, specificity of 74% and an accuracy of 77%, cancer and normal tissue with a sensitivity of 79%, specificity of 83% and an accuracy of 81%. Additionally applied outlier identification enabled us to improve the recognition of neoplastic biopsy samples.

  19. Raman fiber-optical method for colon cancer detection: Cross-validation and outlier identification approach.

    Science.gov (United States)

    Petersen, D; Naveed, P; Ragheb, A; Niedieker, D; El-Mashtoly, S F; Brechmann, T; Kötting, C; Schmiegel, W H; Freier, E; Pox, C; Gerwert, K

    2017-06-15

    Endoscopy plays a major role in early recognition of cancer which is not externally accessible and therewith in increasing the survival rate. Raman spectroscopic fiber-optical approaches can help to decrease the impact on the patient, increase objectivity in tissue characterization, reduce expenses and provide a significant time advantage in endoscopy. In gastroenterology an early recognition of malign and precursor lesions is relevant. Instantaneous and precise differentiation between adenomas as precursor lesions for cancer and hyperplastic polyps on the one hand and between high and low-risk alterations on the other hand is important. Raman fiber-optical measurements of colon biopsy samples taken during colonoscopy were carried out during a clinical study, and samples of adenocarcinoma (22), tubular adenomas (141), hyperplastic polyps (79) and normal tissue (101) from 151 patients were analyzed. This allows us to focus on the bioinformatic analysis and to set stage for Raman endoscopic measurements. Since spectral differences between normal and cancerous biopsy samples are small, special care has to be taken in data analysis. Using a leave-one-patient-out cross-validation scheme, three different outlier identification methods were investigated to decrease the influence of systematic errors, like a residual risk in misplacement of the sample and spectral dilution of marker bands (esp. cancerous tissue) and therewith optimize the experimental design. Furthermore other validations methods like leave-one-sample-out and leave-one-spectrum-out cross-validation schemes were compared with leave-one-patient-out cross-validation. High-risk lesions were differentiated from low-risk lesions with a sensitivity of 79%, specificity of 74% and an accuracy of 77%, cancer and normal tissue with a sensitivity of 79%, specificity of 83% and an accuracy of 81%. Additionally applied outlier identification enabled us to improve the recognition of neoplastic biopsy samples. Copyright

  20. OPTICAL CROSS-CORRELATION FILTERS: AN ECONOMICAL APPROACH FOR IDENTIFYING SNe Ia AND ESTIMATING THEIR REDSHIFTS

    International Nuclear Information System (INIS)

    Scolnic, Daniel M.; Riess, Adam G.; Huber, Mark E.; Rest, Armin; Stubbs, Christoper W.; Tonry, John L.

    2009-01-01

    Large photometric surveys of transient phenomena, such as Panoramic Survey Telescope and Rapid Response System and Large Synoptic Survey Telescope, will locate thousands to millions of Type Ia supernova (SN Ia) candidates per year, a rate prohibitive for acquiring spectroscopy to determine each candidate's type and redshift. In response, we have developed an economical approach to identifying SNe Ia and their redshifts using an uncommon type of optical filter which has multiple, discontinuous passbands on a single substrate. Observation of a supernova through a specially designed pair of these 'cross-correlation filters' measures the approximate amplitude and phase of the cross-correlation between the spectrum and a SN Ia template, a quantity typically used to determine the redshift and type of a high-redshift SN Ia. Simulating the use of these filters, we obtain a sample of SNe Ia which is ∼98% pure with individual redshifts measured to σ z = 0.01 precision. The advantages of this approach over standard broadband photometric methods are that it is insensitive to reddening, independent of the color data used for subsequent distance determinations which reduce selection or interpretation bias, and because it makes use of the spectral features its reliability is greater. A great advantage over long-slit spectroscopy comes from increased throughput, enhanced multiplexing, and reduced setup time resulting in a net gain in speed of up to ∼30 times. This approach is also insensitive to host galaxy contamination. Prototype filters were built and successfully used on Magellan with LDSS-3 to characterize three SuperNova Legacy Survey candidates. We discuss how these filters can provide critical information for the upcoming photometric supernova surveys.

  1. How to design fiber optic sensors that work: basic technology, main problems, pitfalls, and potential solutions

    OpenAIRE

    Dakin, J.P.

    1999-01-01

    Summary• Overview of optical fibre sensor types(Classified according to operating principles)• Difference between intrinsic and extrinsic sensors• Intensity-based sensors• Spectrally-encoded sensors• Propagation-time-encoded sensors• Interferometric sensors• Discussion of how to avoid problems and make practical sensors• Multiplexed and distributed sensors

  2. Microsurgical training model for residents to approach to the orbit and the optic nerve in fresh cadaveric sheep cranium

    Directory of Open Access Journals (Sweden)

    M Emre Altunrende

    2014-01-01

    Full Text Available Background: Neurosurgery and ophthalmology residents need many years to improve microsurgical skills. Laboratory training models are very important for developing surgical skills before clinical application of microsurgery. A simple simulation model is needed for residents to learn how to handle microsurgical instruments and to perform safe dissection of intracranial or intraorbital nerves, vessels, and other structures. Materials and Methods: The simulation material consists of a one-year-old fresh cadaveric sheep cranium. Two parts (Part 1 and Part 2 were designed to approach structures of the orbit. Part 1 consisted of a 2-step approach to dissect intraorbital structures, and Part 2 consisted of a 3-step approach to dissect the optic nerve intracranially. Results: The model simulates standard microsurgical techniques using a variety of approaches to structures in and around the orbit and the optic nerve. Conclusions: This laboratory training model enables trainees to gain experience with an operating microscope, microsurgical instruments and orbital structures.

  3. Generalised analysis of the potential of an enterprise as a function of environmental parameters (theoretical approach

    Directory of Open Access Journals (Sweden)

    Karapeychik Igor M.

    2013-03-01

    Full Text Available Within the frameworks of the author’s concept of the potential of an enterprise as the ability to conduct its immanently appropriate activity and also the idea of presentation of the size of the potential in the form of potential function from parameters of the state of an enterprise and foreign economic environment the article develops a scientific and methodical approach to construction and analysis of the potential function of an enterprise. The offered approach envisages building an economic and mathematical model of an enterprise of the optimisation type with consideration of environmental factors, determination of the size of economic potential as a maximum possible (optimal with the set condition of an enterprise and external environment of net income, statistical test of the model with possible values of external parameters (formation of statistical sampling of the graph of the potential function of an enterprise and application of statistical methods including methods of correlation, factor and regression analysis, for the study of its properties. Operability of this approach is shown on the example of the study of properties of the potential function of a model enterprise. In the course of approbation the article demonstrates its ability to reveal specific features of impact of external factors on economic potential of an enterprise; establishes, as a common regularity, differential influence of various environmental factors, caused not only by the nature of these factors, but also production and economic specific features and specific state of an enterprise. The article shows that the quantitative values of the force of influence of the said factors upon the value of economic potential, obtained during statistical analysis of the potential function of an enterprise, could serve as an instrument of ranking these factors by the priority level in the goal setting tasks at the stage of formation of the strategy of enterprise development

  4. Vibrational spectroscopic, structural and nonlinear optical activity studies on 6-aminonicotinamide: A DFT approach

    Energy Technology Data Exchange (ETDEWEB)

    Asath, R. Mohamed; Premkumar, S.; Mathavan, T.; Benial, A. Milton Franklin, E-mail: miltonfranklin@yahoo.com [Department of Physics, N.M.S.S.V.N College, Madurai-625019, Tamilnadu (India); Rekha, T. N. [PG & Research Department of Physics, Lady Doak College, Madurai 625002, Tamilnadu (India); Jawahar, A. [Department of Chemistry, N.M.S.S.V.N College, Madurai-625019, Tamilnadu (India)

    2016-05-23

    The conformational analysis was carried out for 6-aminonicotinamide (ANA) using potential energy surface scan method and the most stable optimized conformer was predicted. The theoretical vibrational frequencies were calculated for the optimized geometry using DFT/B3LYP cc-pVQZ basis set by Gaussian 09 Program. The vibrational frequencies were assigned on the basis of potential energy distribution calculation using VEDA 4.0 program. The Mulliken atomic charge values were calculated. In the Frontier molecular orbitals analysis, the molecular reactivity, kinetic stability, intermolecular charge transfer studies and the related molecular properties were calculated. The ultraviolet-visible spectrum was simulated for both in the gas phase and liquid phase (ethanol) and the π to π* electronic transition was predicted. The nonlinear optical (NLO) activity was studied by means of the first order hyperpolarizability value, which was 8.61 times greater than the urea and the natural bond orbital analysis was also performed to confirm the NLO activity of the molecule. Hence, the ANA molecule is a promising candidate for the NLO materials.

  5. Vibrational spectroscopic, structural and nonlinear optical activity studies on 6-aminonicotinamide: A DFT approach

    Science.gov (United States)

    Asath, R. Mohamed; Premkumar, S.; Rekha, T. N.; Jawahar, A.; Mathavan, T.; Benial, A. Milton Franklin

    2016-05-01

    The conformational analysis was carried out for 6-aminonicotinamide (ANA) using potential energy surface scan method and the most stable optimized conformer was predicted. The theoretical vibrational frequencies were calculated for the optimized geometry using DFT/B3LYP cc-pVQZ basis set by Gaussian 09 Program. The vibrational frequencies were assigned on the basis of potential energy distribution calculation using VEDA 4.0 program. The Mulliken atomic charge values were calculated. In the Frontier molecular orbitals analysis, the molecular reactivity, kinetic stability, intermolecular charge transfer studies and the related molecular properties were calculated. The ultraviolet-visible spectrum was simulated for both in the gas phase and liquid phase (ethanol) and the л to л* electronic transition was predicted. The nonlinear optical (NLO) activity was studied by means of the first order hyperpolarizability value, which was 8.61 times greater than the urea and the natural bond orbital analysis was also performed to confirm the NLO activity of the molecule. Hence, the ANA molecule is a promising candidate for the NLO materials.

  6. Ventricular filling slows epicardial conduction and increases action potential duration in an optical mapping study of the isolated rabbit heart

    Science.gov (United States)

    Sung, Derrick; Mills, Robert W.; Schettler, Jan; Narayan, Sanjiv M.; Omens, Jeffrey H.; McCulloch, Andrew D.; McCullough, A. D. (Principal Investigator)

    2003-01-01

    INTRODUCTION: Mechanical stimulation can induce electrophysiologic changes in cardiac myocytes, but how mechanoelectric feedback in the intact heart affects action potential propagation remains unclear. METHODS AND RESULTS: Changes in action potential propagation and repolarization with increased left ventricular end-diastolic pressure from 0 to 30 mmHg were investigated using optical mapping in isolated perfused rabbit hearts. With respect to 0 mmHg, epicardial strain at 30 mmHg in the anterior left ventricle averaged 0.040 +/- 0.004 in the muscle fiber direction and 0.032 +/- 0.006 in the cross-fiber direction. An increase in ventricular loading increased average epicardial activation time by 25%+/- 3% (P action potential duration at 20% repolarization (APD20) but did at 80% repolarization (APD80), from 179 +/- 7 msec to 207 +/- 5 msec (P action potential duration by a load-dependent mechanism that may not involve stretch-activated channels.

  7. An approach for flood monitoring by the combined use of Landsat 8 optical imagery and COSMO-SkyMed radar imagery

    Science.gov (United States)

    Tong, Xiaohua; Luo, Xin; Liu, Shuguang; Xie, Huan; Chao, Wei; Liu, Shuang; Liu, Shijie; Makhinov, A. N.; Makhinova, A. F.; Jiang, Yuying

    2018-02-01

    Remote sensing techniques offer potential for effective flood detection with the advantages of low-cost, large-scale, and real-time surface observations. The easily accessible data sources of optical remote sensing imagery provide abundant spectral information for accurate surface water body extraction, and synthetic aperture radar (SAR) systems represent a powerful tool for flood monitoring because of their all-weather capability. This paper introduces a new approach for flood monitoring by the combined use of both Landsat 8 optical imagery and COSMO-SkyMed radar imagery. Specifically, the proposed method applies support vector machine and the active contour without edges model for water extent determination in the periods before and during the flood, respectively. A map difference method is used for the flood inundation analysis. The proposed approach is particularly suitable for large-scale flood monitoring, and it was tested on a serious flood that occurred in northeastern China in August 2013, which caused immense loss of human lives and properties. High overall accuracies of 97.46% for the optical imagery and 93.70% for the radar imagery are achieved by the use of the techniques presented in this study. The results show that about 12% of the whole study area was inundated, corresponding to 5466 km2 of land surface.

  8. The potential of landscape labelling approaches for integrated landscape management in Europe

    DEFF Research Database (Denmark)

    Mann, Carsten; Plieninger, Tobias

    2017-01-01

    This paper combines conceptual thinking and empirical analysis of landscape labelling as a new governance approach. With the help of a literature review and qualitative interviews, we (1) explore the conceptual orientation of landscape labelling, (2) analyse existing approaches in Europe and (3......) elaborate its potential for integrated landscape management on a regional scale. Governance analysis to identify fostering and hindering factors is carried out for regional brands in biosphere reserves in Germany, geographic indication in Spain, organic agriculture in France and a community forest...... approach within policy mixes that depend on supportive governance structures and stakeholders....

  9. Potential errors in optical density measurements due to scanning side in EBT and EBT2 Gafchromic film dosimetry.

    Science.gov (United States)

    Desroches, Joannie; Bouchard, Hugo; Lacroix, Frédéric

    2010-04-01

    The purpose of this study is to determine the effect on the measured optical density of scanning on either side of a Gafchromic EBT and EBT2 film using an Epson (Epson Canada Ltd., Toronto, Ontario) 10000XL flat bed scanner. Calibration curves were constructed using EBT2 film scanned in landscape orientation in both reflection and transmission mode on an Epson 10000XL scanner. Calibration curves were also constructed using EBT film. Potential errors due to an optical density difference from scanning the film on either side ("face up" or "face down") were simulated. Scanning the film face up or face down on the scanner bed while keeping the film angular orientation constant affects the measured optical density when scanning in reflection mode. In contrast, no statistically significant effect was seen when scanning in transmission mode. This effect can significantly affect relative and absolute dose measurements. As an application example, the authors demonstrate potential errors of 17.8% by inverting the film scanning side on the gamma index for 3%-3 mm criteria on a head and neck intensity modulated radiotherapy plan, and errors in absolute dose measurements ranging from 10% to 35% between 2 and 5 Gy. Process consistency is the key to obtaining accurate and precise results in Gafchromic film dosimetry. When scanning in reflection mode, care must be taken to place the film consistently on the same side on the scanner bed.

  10. Technical Note: Potential errors in optical density measurements due to scanning side in EBT and EBT2 Gafchromic film dosimetry

    International Nuclear Information System (INIS)

    Desroches, Joannie; Bouchard, Hugo; Lacroix, Frederic

    2010-01-01

    Purpose: The purpose of this study is to determine the effect on the measured optical density of scanning on either side of a Gafchromic EBT and EBT2 film using an Epson (Epson Canada Ltd., Toronto, Ontario) 10000XL flat bed scanner. Methods: Calibration curves were constructed using EBT2 film scanned in landscape orientation in both reflection and transmission mode on an Epson 10000XL scanner. Calibration curves were also constructed using EBT film. Potential errors due to an optical density difference from scanning the film on either side (''face up'' or ''face down'') were simulated. Results: Scanning the film face up or face down on the scanner bed while keeping the film angular orientation constant affects the measured optical density when scanning in reflection mode. In contrast, no statistically significant effect was seen when scanning in transmission mode. This effect can significantly affect relative and absolute dose measurements. As an application example, the authors demonstrate potential errors of 17.8% by inverting the film scanning side on the gamma index for 3%--3 mm criteria on a head and neck intensity modulated radiotherapy plan, and errors in absolute dose measurements ranging from 10% to 35% between 2 and 5 Gy. Conclusions: Process consistency is the key to obtaining accurate and precise results in Gafchromic film dosimetry. When scanning in reflection mode, care must be taken to place the film consistently on the same side on the scanner bed.

  11. The potential of positive deviance approach for the sustainable control of neglected tropical diseases.

    Science.gov (United States)

    Ong, Ken Ing Cherng; Araki, Hitomi; Kano, Shigeyuki; Jimba, Masamine

    2016-01-01

    Neglected tropical diseases (NTDs) have gained much attention in recent years due to the support from various agencies. However, the main approach to combat NTDs has been to cure rather than to prevent. As many NTD infections are closely linked with human behaviors such as hygienic practices and tradition, behavior change is also very crucial to prevent relapse or reinfection. Therefore, we would like to suggest a potential new approach-the positive deviance approach-to tackle NTDs by focusing on the preventive phase. What makes this approach unique is that the solution comes from the affected population themselves and not from the expert outsiders. Preventive chemotherapy that relies on outside aid has serious sustainability issues as reinfection is also high after the aid program has ended. Learning from the success story in Vietnam on preventing childhood malnutrition, the positive deviance approach could end the spread of NTDs once and for all by making full use of the available local solutions.

  12. Potential of optical spectral transmission measurements for joint inflammation measurements in rheumatoid arthritis patients

    Science.gov (United States)

    Meier, A. J. Louise; Rensen, Wouter H. J.; de Bokx, Pieter K.; de Nijs, Ron N. J.

    2012-08-01

    Frequent monitoring of rheumatoid arthritis (RA) patients enables timely treatment adjustments and improved outcomes. Currently this is not feasible due to a shortage of rheumatologists. An optical spectral transmission device is presented for objective assessment of joint inflammation in RA patients, while improving diagnostic accuracy and clinical workflow. A cross-sectional, nonrandomized observational study was performed with this device. In the study, 77 proximal interphalangeal (PIP) joints in 67 patients have been analyzed. Inflammation of these PIP joints was also assessed by a rheumatologist with a score varying from 1 (not inflamed) to 5 (severely inflamed). Out of 77 measurements, 27 were performed in moderate to strongly inflamed PIP joints. Comparison between the clinical assessment and an optical measurement showed a correlation coefficient r=0.63, p<0.001, 95% CI [0.47, 0.75], and a ROC curve (AUC=0.88) that shows a relative good specificity and sensitivity. Optical spectral transmission measurements in a single joint correlate with clinical assessment of joint inflammation, and therefore might be useful in monitoring joint inflammation in RA patients.

  13. Optical coherence tomography: a potential tool to predict premature rupture of fetal membranes.

    Science.gov (United States)

    Micili, Serap C; Valter, Markus; Oflaz, Hakan; Ozogul, Candan; Linder, Peter; Föckler, Nicole; Artmann, Gerhard M; Digel, Ilya; Artmann, Aysegul T

    2013-04-01

    A fundamental question addressed in this study was the feasibility of preterm birth prediction based on a noncontact investigation of fetal membranes in situ. Although the phenomena of preterm birth and the premature rupture of the fetal membrane are well known, currently, there are no diagnostic tools for their prediction. The aim of this study was to assess whether optical coherence tomography could be used for clinical investigations of high-risk pregnancies. The thickness of fetal membranes was measured in parallel by optical coherence tomography and histological techniques for the following types of birth: normal births, preterm births without premature ruptures and births at full term with premature rupture of membrane. Our study revealed that the membrane thickness correlates with the birth type. Normal births membranes were statistically significantly thicker than those belonging to the other two groups. Thus, in spite of almost equal duration of gestation of the normal births and the births at full term with premature rupture, the corresponding membrane thicknesses differed. This difference is possibly related to previously reported water accumulation in the membranes. The optical coherence tomography results were encouraging, suggesting that this technology could be used in future to predict and distinguish between different kinds of births.

  14. Gibbsian segregating alloys driven by thermal and concentration gradients: A potential grazing collector optics used in EUV lithography

    Science.gov (United States)

    Qiu, Huatan

    the temperature and surface removal rate. The Mo-Au GS alloy could be effective at elevated temperature as the potential grazing mirror as EUV collector optics.

  15. Investigation of the shape of the imaginary part of the optical-model potential for electron scattering by rare gases

    International Nuclear Information System (INIS)

    Staszewska, G.; Schwenke, D.W.; Truhlar, D.G.

    1984-01-01

    We present a comparative study of several empirical and nonempirical models for the absorption potential, which is the imaginary part of an optical-model potential, for electron scattering by rare gases. We show that the elastic differential cross section is most sensitive to the absorption potential for high-impact energy and large scattering angles. We compare differential cross sections calculated by several models for the absorption potential and by several arbitrary modifications of these model potentials. We are able to associate the effect of the absorption potential on the elastic differential cross section with its form at small electron-atom distances r, and we are able to deduce various qualitative features that the absorption potential must possess at small and large r in order to predict both accurate differential cross sections and accurate absorption cross sections. Based on these observations, the Pauli blocking conditions of the quasifree scattering model for the absorption potential are modified empirically, thus producing a more accurate model that may be applied to other systems; e.g., electron-molecule scattering, with no adjustable parameters

  16. Optical coherence tomography for blood glucose monitoring in vitro through spatial and temporal approaches

    Science.gov (United States)

    De Pretto, Lucas Ramos; Yoshimura, Tania Mateus; Ribeiro, Martha Simões; Zanardi de Freitas, Anderson

    2016-08-01

    As diabetes causes millions of deaths worldwide every year, new methods for blood glucose monitoring are in demand. Noninvasive approaches may increase patient adherence to treatment while reducing costs, and optical coherence tomography (OCT) may be a feasible alternative to current invasive diagnostics. This study presents two methods for blood sugar monitoring with OCT in vitro. The first, based on spatial statistics, exploits changes in the light total attenuation coefficient caused by different concentrations of glucose in the sample using a 930-nm commercial OCT system. The second, based on temporal analysis, calculates differences in the decorrelation time of the speckle pattern in the OCT signal due to blood viscosity variations with the addition of glucose with data acquired by a custom built Swept Source 1325-nm OCT system. Samples consisted of heparinized mouse blood, phosphate buffer saline, and glucose. Additionally, further samples were prepared by diluting mouse blood with isotonic saline solution to verify the effect of higher multiple scattering components on the ability of the methods to differentiate glucose levels. Our results suggest a direct relationship between glucose concentration and both decorrelation rate and attenuation coefficient, with our systems being able to detect changes of 65 mg/dL in glucose concentration.

  17. Challenges in Ecohydrological Monitoring at Soil-Vegetation Interfaces: Exploiting the Potential for Fibre Optic Technologies

    Science.gov (United States)

    Chalari, A.; Ciocca, F.; Krause, S.; Hannah, D. M.; Blaen, P.; Coleman, T. I.; Mondanos, M.

    2015-12-01

    The Birmingham Institute of Forestry Research (BIFoR) is using Free-Air Carbon Enrichment (FACE) experiments to quantify the long-term impact and resilience of forests into rising atmospheric CO2 concentrations. The FACE campaign critically relies on a successful monitoring and understanding of the large variety of ecohydrological processes occurring across many interfaces, from deep soil to above the tree canopy. At the land-atmosphere interface, soil moisture and temperature are key variables to determine the heat and water exchanges, crucial to the vegetation dynamics as well as to groundwater recharge. Traditional solutions for monitoring soil moisture and temperature such as remote techniques and point sensors show limitations in fast acquisition rates and spatial coverage, respectively. Hence, spatial patterns and temporal dynamics of heat and water fluxes at this interface can only be monitored to a certain degree, limiting deeper knowledge in dynamically evolving systems (e.g. in impact of growing vegetation). Fibre optics Distributed Temperature Sensors (DTS) can measure soil temperatures at high spatiotemporal resolutions and accuracy, along kilometers of optical cable buried in the soil. Heat pulse methods applied to electrical elements embedded in the optical cable can be used to obtain the soil moisture. In July 2015 a monitoring system based on DTS has been installed in a recently forested hillslope at BIFoR in order to quantify high-resolution spatial patterns and high-frequency temporal dynamics of soil heat fluxes and soil moisture conditions. Therefore, 1500m of optical cables have been carefully deployed in three overlapped loops at 0.05m, 0.25m and 0.4m from the soil surface and an electrical system to send heat pulses along the optical cable has been developed. This paper discussed both, installation and design details along with first results of the soil moisture and temperature monitoring carried out since July 2015. Moreover, interpretations

  18. A potential approach for low flow selection in water resource supply and management

    Science.gov (United States)

    Ouyang, Ying

    2012-08-01

    SummaryLow flow selections are essential to water resource management, water supply planning, and watershed ecosystem restoration. In this study, a new approach, namely the frequent-low (FL) approach (or frequent-low index), was developed based on the minimum frequent-low flow or level used in minimum flows and/or levels program in northeast Florida, USA. This FL approach was then compared to the conventional 7Q10 approach for low flow selections prior to its applications, using the USGS flow data from the freshwater environment (Big Sunflower River, Mississippi) as well as from the estuarine environment (St. Johns River, Florida). Unlike the FL approach that is associated with the biological and ecological impacts, the 7Q10 approach could lead to the selections of extremely low flows (e.g., near-zero flows) that may hinder its use for establishing criteria to prevent streams from significant harm to biological and ecological communities. Additionally, the 7Q10 approach could not be used when the period of data records is less than 10 years by definition while this may not the case for the FL approach. Results from both approaches showed that the low flows from the Big Sunflower River and the St. Johns River decreased as time elapsed, demonstrating that these two rivers have become drier during the last several decades with a potential of salted water intrusion to the St. Johns River. Results from the FL approach further revealed that the recurrence probability of low flow increased while the recurrence interval of low flow decreased as time elapsed in both rivers, indicating that low flows occurred more frequent in these rivers as time elapsed. This report suggests that the FL approach, developed in this study, is a useful alternative for low flow selections in addition to the 7Q10 approach.

  19. Sum rules for the ed - NN scattering reactions and microscopic potential field-theoretical approach

    International Nuclear Information System (INIS)

    Machivariani, A.I.

    1996-01-01

    The connections between the equal-time commutators of nucleon and photon field-operators and relativistic potential approach of ed - NN scattering equations is established. Namely, it is demonstrated that: 1) equal-time commutator between nucleon field operators generated completeness condition for NN interaction functions, 2) the off-mass shell contributions in γd - NN exchange currents or in microscopic NN potential are determined by equal time commutator between nucleon field operator and photon or nucleon source operators, and 3) equal-time commutators between source operators produce sum rules for same vertex functions and effective potentials [ru

  20. A Taguchi PCA fuzzy-based approach for the multi-objective extended optimization of a miniature optical engine

    International Nuclear Information System (INIS)

    Fan Yichin; Tzeng Yihfong; Li Sixiang

    2008-01-01

    The paper proposes a hybrid approach, integrating a combination of Taguchi methods, principal component analysis (PCA) and fuzzy theory for the extended optimization of multiple quality characteristics in optimization experiments of non-image optics; a miniature light emitting diode pocket-sized projection display system is demonstrated in this research as an optimization sample. Traditionally, the performance of projector optics can be evaluated by modulation transfer function and its optimization method is DLS (damped least square). Comparatively, light efficiency and uniformity play a part in non-image optics where the optimized method is based on the concept of non-sequential rays; for example, in the optical engine of a projector, which demands better light efficiency and uniformity. The DLS method is occasionally employed in the optimization of non-image optics such as optical engines, but it is sometimes sensitive to the number of rays employed and some over-optimization problems. In this research we propose as an alternative method to optimize in an extended way the optical engine of a miniature projector. Control factors were checked and then repeatedly examined before the experiments started. In the experiment, optimization works through an L18 orthogonal array. Finally, this proposed optimization work shows good success for the optimization of non-image optical engines because this method is less sensitive to the number of non-sequential rays. Compared with the initial design, the optimized parameter design is able to improve the luminous flux by 11.46 dB, the illumination uniformity by 3.14 and the packing size by 1.125 dB

  1. The effects of cortisol administration on approach-avoidance behavior: An event-related potential study

    NARCIS (Netherlands)

    Peer, J.M. van; Roelofs, K.; Rotteveel, M.; Dijk, J.G. van; Spinhoven, P.; Ridderinkhof, K.R.

    2007-01-01

    We investigated the effects of cortisol administration (50 mg) on approach and avoidance tendencies in low and high trait avoidant healthy young men. Event-related brain potentials (ERPs) were measured during a reaction time task, in which participants evaluated the emotional expression of

  2. Quasi-potential approach to the problem of bound states in quantum electrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Rizov, V A; Todorov, I T [Bylgarska Akademiya na Naukite, Sofia. Inst. za Yadrena Izsledvaniya i Yadrena Energetika

    1975-07-01

    The paper reviews two types of quasipotential equations. An equation with a non-local potential is derived from the equations of motion of quantum electrodynamics. It is also related to a Bethe-Salpeter type of equation for the retarded Green function. Most of the paper is devoted to a systematic study of a local version of the Logunov-Tavkhelidze quasipotential approach.

  3. Safeguards decision making in the public and regulatory environment, and the potential role of quantitative approaches

    International Nuclear Information System (INIS)

    Sherr, T.S.

    1981-01-01

    This paper briefly examines the nature of the safeguards program's objectives and constraints, and the inherent limitations on comprehensive quantification. It discusses the nature of the public and regulatory processes employed in safeguards decision making, and examines their implications regarding the potential role of quantitative approaches to safeguards policy and operational decision making

  4. Geothermal potential assessment for a low carbon strategy : A new systematic approach applied in southern Italy

    NARCIS (Netherlands)

    Trumpy, E.; Botteghi, S.; Caiozzi, F.; Donato, A.; Gola, G.; Montanari, D.; Pluymaekers, M. P D; Santilano, A.; van Wees, J. D.; Manzella, A.

    2016-01-01

    In this study a new approach to geothermal potential assessment was set up and applied in four regions in southern Italy. Our procedure, VIGORThermoGIS, relies on the volume method of assessment and uses a 3D model of the subsurface to integrate thermal, geological and petro-physical data. The

  5. HOLISTIC APPROACH FOR ASSESSING THE PRESENCE AND POTENTIAL IMPACTS OF WATERBORNE ENVIRONMENTAL CONTAMINANTS

    Science.gov (United States)

    As an integral part of our continuing research in environmental quality assessment approaches, we have developed a variety of passive integrative sampling devices widely applicable for use in defining the presence and potential impacts of a broad array of contaminants. The semipe...

  6. Geothermal potential assessment for a low carbon strategy: A new systematic approach applied in southern Italy

    NARCIS (Netherlands)

    Trumpy, E.; Botteghi, S.; Caiozzi, F.; Donato, A.; Gola, G.; Montanari, D.; Pluymaekers, M.P.D.; Santilano, A.; Wees, J.D. van; Manzella, A.

    2016-01-01

    In this study a new approach to geothermal potential assessment was set up and applied in four regions in southern Italy. Our procedure, VIGORThermoGIS, relies on the volume method of assessment and uses a 3D model of the subsurface to integrate thermal, geological and petro-physical data. The

  7. Developing TheoreticalMethodological Approaches to Assessment of Export Potential of Ukrainian Enterprises

    Directory of Open Access Journals (Sweden)

    Matyushenko Igor Yu.

    2016-02-01

    Full Text Available The article is aimed at studying the existing theoretical-methodological approaches to the analysis and assessment of export potential. The opinions by scientists regarding the disclosure of the categorial content of the concept of «export potential» have been considered, an own definition of the indicated economic category has been suggested. The main types of analytical procedures for assessment have been classified, some authorial methodical approaches to determine the level of export potential have been analyzed. The export potential of a hypothetical enterprise has been calculated by the selected methodologies of assessment. The urgency of improving and refining existing methods to implement more detailed and quantitative analysis has been substantiated. It has been suggested to implement a prognosis assessment of export potential of enterprises by combining the results of several methodologies in the aggregate indicator of export potential efficiency. A prognosis model for the dynamics of export potential of a hypothetical enterprise has been built, value of the aggregate indicator has been calculated on the basis of three selected valuation methodologies.

  8. Improving the variational path integral approach to the quantum double-well potential

    International Nuclear Information System (INIS)

    Bao Jingdong; Wang Hongyu

    2002-01-01

    An improved variational path integral approach is developed and applied to the quantum double-well potential, in which part of the quartic term of the potential is included in the trial action. The expression of the effective classical potential (ECP) under a non-Gaussian expectation is obtained. Here the frequency and fourth-order derivative of the potential are treated as two variational parameters, determined by the minimization of the ECP at each point. We calculate the ECP, the free energy and the level splitting of a symmetrical double-well potential. It is shown that the present results are better than those of the Feynman-Kleinert Gaussian variational method. (author)

  9. Magneto-optical absorption in semiconducting spherical quantum dots: Influence of the dot-size, confining potential, and magnetic field

    Directory of Open Access Journals (Sweden)

    Manvir S. Kushwaha

    2014-12-01

    Full Text Available Semiconducting quantum dots – more fancifully dubbed artificial atoms – are quasi-zero dimensional, tiny, man-made systems with charge carriers completely confined in all three dimensions. The scientific quest behind the synthesis of quantum dots is to create and control future electronic and optical nanostructures engineered through tailoring size, shape, and composition. The complete confinement – or the lack of any degree of freedom for the electrons (and/or holes – in quantum dots limits the exploration of spatially localized elementary excitations such as plasmons to direct rather than reciprocal space. Here we embark on a thorough investigation of the magneto-optical absorption in semiconducting spherical quantum dots characterized by a confining harmonic potential and an applied magnetic field in the symmetric gauge. This is done within the framework of Bohm-Pines’ random-phase approximation that enables us to derive and discuss the full Dyson equation that takes proper account of the Coulomb interactions. As an application of our theoretical strategy, we compute various single-particle and many-particle phenomena such as the Fock-Darwin spectrum; Fermi energy; magneto-optical transitions; probability distribution; and the magneto-optical absorption in the quantum dots. It is observed that the role of an applied magnetic field on the absorption spectrum is comparable to that of a confining potential. Increasing (decreasing the strength of the magnetic field or the confining potential is found to be analogous to shrinking (expanding the size of the quantum dots: resulting into a blue (red shift in the absorption spectrum. The Fermi energy diminishes with both increasing magnetic-field and dot-size; and exhibits saw-tooth-like oscillations at large values of field or dot-size. Unlike laterally confined quantum dots, both (upper and lower magneto-optical transitions survive even in the extreme instances. However, the intra

  10. Magneto-optical absorption in semiconducting spherical quantum dots: Influence of the dot-size, confining potential, and magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Kushwaha, Manvir S. [Department of Physics and Astronomy, Rice University, P.O. Box 1892, Houston, TX 77251 (United States)

    2014-12-15

    Semiconducting quantum dots – more fancifully dubbed artificial atoms – are quasi-zero dimensional, tiny, man-made systems with charge carriers completely confined in all three dimensions. The scientific quest behind the synthesis of quantum dots is to create and control future electronic and optical nanostructures engineered through tailoring size, shape, and composition. The complete confinement – or the lack of any degree of freedom for the electrons (and/or holes) – in quantum dots limits the exploration of spatially localized elementary excitations such as plasmons to direct rather than reciprocal space. Here we embark on a thorough investigation of the magneto-optical absorption in semiconducting spherical quantum dots characterized by a confining harmonic potential and an applied magnetic field in the symmetric gauge. This is done within the framework of Bohm-Pines’ random-phase approximation that enables us to derive and discuss the full Dyson equation that takes proper account of the Coulomb interactions. As an application of our theoretical strategy, we compute various single-particle and many-particle phenomena such as the Fock-Darwin spectrum; Fermi energy; magneto-optical transitions; probability distribution; and the magneto-optical absorption in the quantum dots. It is observed that the role of an applied magnetic field on the absorption spectrum is comparable to that of a confining potential. Increasing (decreasing) the strength of the magnetic field or the confining potential is found to be analogous to shrinking (expanding) the size of the quantum dots: resulting into a blue (red) shift in the absorption spectrum. The Fermi energy diminishes with both increasing magnetic-field and dot-size; and exhibits saw-tooth-like oscillations at large values of field or dot-size. Unlike laterally confined quantum dots, both (upper and lower) magneto-optical transitions survive even in the extreme instances. However, the intra-Landau level

  11. The K + - Nucleus Microscopic Optical Potential and Calculations of the Corresponding Differential Elastic and Total Reaction Cross Sections

    International Nuclear Information System (INIS)

    Zemlyanaya, E.V.; Lukyanov, K.V.; Lukyanov, V.K.; Hanna, K.M.

    2009-01-01

    The microscopic optical potential (OP) is calculated for the K+-meson scattering on the 12 C and 40 Ca nuclei at intermediate energies. This potential has no free parameters and based on the known kaon-nucleon amplitude and nuclear density distribution functions. Then, the Klein-Gordon equation is written in the form of the relativistic Schrodinger equation where terms quadratic in the potential was estimated can be neglected. The latter equations adapted to the considered task and solved numerically. The effect of revitalization is shown to play a significant role. A good agreement with the experimental data on differential elastic cross sections is obtained. However, to explain the data on total reaction cross sections the additional surface term of OP was introduced to account for influence of the peripheral nuclear reaction channels

  12. Numerical solution of the full potential equation using a chimera grid approach

    Science.gov (United States)

    Holst, Terry L.

    1995-01-01

    A numerical scheme utilizing a chimera zonal grid approach for solving the full potential equation in two spatial dimensions is described. Within each grid zone a fully-implicit approximate factorization scheme is used to advance the solution one interaction. This is followed by the explicit advance of all common zonal grid boundaries using a bilinear interpolation of the velocity potential. The presentation is highlighted with numerical results simulating the flow about a two-dimensional, nonlifting, circular cylinder. For this problem, the flow domain is divided into two parts: an inner portion covered by a polar grid and an outer portion covered by a Cartesian grid. Both incompressible and compressible (transonic) flow solutions are included. Comparisons made with an analytic solution as well as single grid results indicate that the chimera zonal grid approach is a viable technique for solving the full potential equation.

  13. Inelastic 12C(12C, 12C)12C scattering via the Glauber optical potential at E/A=30 MeV and 85 MeV

    International Nuclear Information System (INIS)

    Chauvin, J.; Lebrun, D.; Durand, F.; Buenerd, M.

    1984-07-01

    It is shown that some approximations implied in the optical limit of the Glauber theory are justified for low energies heavy-ions surface collisions. The Glauber optical potential -with no free parameters- leads to reasonable predictions for both elastic and inelastic scattering in the 12 C + 12 C system

  14. Infra-red laser source using Tm:Ho optical fibre for potential sensor applications

    International Nuclear Information System (INIS)

    Chen, S Y; Yeo, T L; Leighton, J; Sun, T; Grattan, K T V; Lade, R; Powell, B; Foster-Turner, G; Osborne, M

    2007-01-01

    In this work, a 1600nm Er fibre laser, which demonstrates a high pumping efficiency, has been used to pump an efficient all-fibre Tm:Ho laser system using a 0.3 m length of optical fibre. A low threshold of 33 mW and a slope efficiency of 0.6% have been achieved with operation at a wavelength of ∼1870 nm. A cross-comparison has been made with the output of a device pumped by a 785 nm laser diode. The focus of the work is better and more compact sources for gas sensing in the near infra red region of the spectrum

  15. Deterministic linear-optics quantum computing based on a hybrid approach

    International Nuclear Information System (INIS)

    Lee, Seung-Woo; Jeong, Hyunseok

    2014-01-01

    We suggest a scheme for all-optical quantum computation using hybrid qubits. It enables one to efficiently perform universal linear-optical gate operations in a simple and near-deterministic way using hybrid entanglement as off-line resources

  16. Deterministic linear-optics quantum computing based on a hybrid approach

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Woo; Jeong, Hyunseok [Center for Macroscopic Quantum Control, Department of Physics and Astronomy, Seoul National University, Seoul, 151-742 (Korea, Republic of)

    2014-12-04

    We suggest a scheme for all-optical quantum computation using hybrid qubits. It enables one to efficiently perform universal linear-optical gate operations in a simple and near-deterministic way using hybrid entanglement as off-line resources.

  17. Temperature dependent optical characterization of Ni-TiO2 thin films as potential photocatalytic material

    Science.gov (United States)

    De, Rajnarayan; Haque, S. Maidul; Tripathi, S.; Rao, K. Divakar; Singh, Ranveer; Som, T.; Sahoo, N. K.

    2017-09-01

    Along with other transition metal doped titanium dioxide materials, Ni-TiO2 is considered to be one of the most efficient materials for catalytic applications due to its suitable energy band positions in the electronic structure. The present manuscript explores the possibility of improving the photocatalytic activity of RF magnetron sputtered Ni-TiO2 films upon heat treatment. Optical, structural and morphological and photocatalytic properties of the films have been investigated in detail for as deposited and heat treated samples. Evolution of refractive index (RI) and total film thickness as estimated from spectroscopic ellipsometry characterization are found to be in agreement with the trend in density and total film thickness estimated from grazing incidence X-ray reflectivity measurement. Interestingly, the evolution of these macroscopic properties were found to be correlated with the corresponding microstructural modifications realized in terms of anatase to rutile phase transformation and appearance of a secondary phase namely NiTiO3 at high temperature. Corresponding morphological properties of the films were also found to be temperature dependent which leads to modifications in the grain structure. An appreciable reduction of optical band gap from 2.9 to 2.5 eV of Ni-TiO2 thin films was also observed as a result of post deposition heat treatment. Testing of photocatalytic activity of the films performed under UV illumination demonstrates heat treatment under atmospheric ambience to be an effective means to enhance the photocatalytic efficiency of transition metal doped titania samples.

  18. The interpretation of resonance formation in coupled-channel models of positron scattering by atomic hydrogen using localized optical potentials

    International Nuclear Information System (INIS)

    Bransden, B.H.; Hewitt, R.N.

    1997-01-01

    Above-threshold resonances can occur in coupled-channel models of the e + + H system when Ps formation is taken into account (although it should be pointed out that, in this specific system, resonances do not occur in an exact theory). In general, to understand the mechanism of resonance formation it is useful to obtain the exact optical potential in a given channel in a localized form. The methods of achieving this localization are discussed with reference to a specific application to the resonance found in the two-state approximation for the l = 0 partial wave. (author)

  19. Alternative Approach of Developing Optical Binary Adder Using Reversible Peres Gates

    Directory of Open Access Journals (Sweden)

    Dhoumendra Mandal

    2018-01-01

    Full Text Available All-optical devices will play a very significant and crucial role in the modern all-optical network by eliminating the bottleneck of opto-electro-opto- (O-E-O- conversion. Unfortunately, the conventional logic gates lose information at the output, and the states of the outputs cannot give any credible impressions of the states of the inputs. In this article, at first, the authors have proposed a method of designing an optical three-input-three-output reversible Peres gate. Authors have deployed polarization switching characteristic of Semiconductor Optical Amplifier (SOA for designing this circuit. The authors have also proposed a method of designing an optical reversible full adder, using two such Peres gates and subsequently a data recovery circuit which can recover the input data of the adder. The authors have chosen frequency encoded data for processing the operation. The proposed scheme has been verified by simulation results.

  20. Effects of levothyroxine on visual evoked potential impairment following local injections of lysolecithin into the rat optic chiasm

    Directory of Open Access Journals (Sweden)

    Cobra Payghani

    2018-01-01

    Full Text Available Background: Multiple sclerosis (MS is a demyelinating disease of the central nervous system which has no any known definitive treatment. Studies have shown that thyroid hormones (THs in addition to their roles in the development of the nervous system and the production of myelin have important roles in the adult's brain function. Since the only way to treat MS is the restoration of myelin, the aim of this study was to evaluate the effects of levothyroxine on visual evoked potential (VEP impairment following local injections of lysolecithin into the rat optic chiasm. Methods: To induce demyelination, lysolecithin was injected into the optic chiasm of male Wistar rats. VEP recording was used to evaluate demyelination and remyelination before and 10, 17, and 24 days after the lysolecithin injection. The rats received an intraperitoneal injection of levothyroxine with doses 20, 50, and 100 μg/kg in different experimental groups. Results: VEP latency and amplitude showed demyelination at 10 and 17 days after an induced lesion in MS group which was reversed at day 24. Levothyroxine prevented these impairments, especially in high doses. Conclusions: According to the results, lysolecithin-induced demyelination at optic chiasm and VEP impairments can be restored by administration of levothyroxine. Therefore, THs probably have positive effects in demyelinating diseases.

  1. Physical properties of asteroids derived from a novel approach to modeling of optical lightcurves and WISE thermalinfrared data

    Science.gov (United States)

    Durech, Josef; Hanus, Josef; Delbo, Marco; Ali-Lagoa, Victor; Carry, Benoit

    2014-11-01

    Convex shape models and spin vectors of asteroids are now routinely derived from their disk-integrated lightcurves by the lightcurve inversion method of Kaasalainen et al. (2001, Icarus 153, 37). These shape models can be then used in combination with thermal infrared data and a thermophysical model to derive other physical parameters - size, albedo, macroscopic roughness and thermal inertia of the surface. In this classical two-step approach, the shape and spin parameters are kept fixed during the thermophysical modeling when the emitted thermal flux is computed from the surface temperature, which is computed by solving a 1-D heat diffusion equation in sub-surface layers. A novel method of simultaneous inversion of optical and infrared data was presented by Durech et al. (2012, LPI Contribution No. 1667, id.6118). The new algorithm uses the same convex shape representation as the lightcurve inversion but optimizes all relevant physical parameters simultaneously (including the shape, size, rotation vector, thermal inertia, albedo, surface roughness, etc.), which leads to a better fit to the thermal data and a reliable estimation of model uncertainties. We applied this method to selected asteroids using their optical lightcurves from archives and thermal infrared data observed by the Wide-field Infrared Survey Explorer (WISE) satellite. We will (i) show several examples of how well our model fits both optical and infrared data, (ii) discuss the uncertainty of derived parameters (namely the thermal inertia), (iii) compare results obtained with the two-step approach with those obtained by our method, (iv) discuss the advantages of this simultaneous approach with respect to the classical two-step approach, and (v) advertise the possibility to use this approach to tens of thousands asteroids for which enough WISE and optical data exist.

  2. Structural, vibrational spectroscopic and nonlinear optical activity studies on 2-hydroxy- 3, 5-dinitropyridine: A DFT approach

    Science.gov (United States)

    Asath, R. Mohamed; Premkumar, S.; Jawahar, A.; Mathavan, T.; Dhas, M. Kumara; Benial, A. Milton Franklin

    2015-06-01

    The conformational analysis was carried out for 2-Hydroxy- 3, 5-dinitropyridine molecule using potential energy surface scan and the most stable optimized conformer was predicted. The vibrational frequencies and Mulliken atomic charge distribution were calculated for the optimized geometry of the molecule using DFT/B3LYP cc-pVQZ basis set by Gaussian 09 Program. The vibrational frequencies were assigned on the basis of potential energy distribution calculation using VEDA 4.0 program. In the Frontier molecular orbitals analysis, the molecular reactivity, kinetic stability, intramolecular charge transfer studies and the calculation of ionization energy, electron affinity, global hardness, chemical potential, electrophilicity index and softness values of the title molecule were carried out. The nonlinear optical activity of the molecule was studied by means of first order hyperpolarizability, which was computed as 7.64 times greater than urea. The natural bond orbital analysis was performed to confirm the nonlinear optical activity of the molecule.

  3. A three-stage-integrative approach for the identification of potential hepatotoxic compounds from botanical products.

    Science.gov (United States)

    Jin, Yecheng; Zhao, Xiaoping; Zhang, Yufeng; Li, Xiang; Nie, Xiaojing; Wang, Yi; Fan, Xiaohui

    2011-05-01

    With the increasing use of herbal medicines and dietary supplements, intensive concerns about their potential toxicities have been raised. Screening and identifying the toxic compounds from these botanical products composed by hundreds of components have become a critical but challenging problem. In this study, 3 methods, including fraction separation, an in-house-developed fluorescein diacetate-based automatic microscopy screening (FAMS) platform, and liquid chromatography-mass spectrometry-based compounds identification were integrated within the Three-Stage-Integrative (TSI) approach for the identification of potential hepatotoxicants from botanical products. The sensitivity and linear range of FAMS assay was validated and compared with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay by previously reported hepatotoxic compounds. The success of TSI approach was further demonstrated by its application to Fructus aristolochiae. Aristolochic acid IVa and aristolodione were tentatively identified to be potential hepatotoxicants in this plant. These applications suggested that our TSI approach provides an effective tool for identifying potential toxic compounds from botanical products.

  4. Comparison of modeling approaches to prioritize chemicals based on estimates of exposure and exposure potential.

    Science.gov (United States)

    Mitchell, Jade; Arnot, Jon A; Jolliet, Olivier; Georgopoulos, Panos G; Isukapalli, Sastry; Dasgupta, Surajit; Pandian, Muhilan; Wambaugh, John; Egeghy, Peter; Cohen Hubal, Elaine A; Vallero, Daniel A

    2013-08-01

    While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecological health outcomes. Recent improvements and advances such as high throughput data gathering, high performance computational capabilities, and predictive chemical inherency methodology make this an opportune time to develop an exposure-based prioritization approach that can systematically utilize and link the asymmetrical bodies of knowledge for hazard and exposure. In response to the US EPA's need to develop novel approaches and tools for rapidly prioritizing chemicals, a "Challenge" was issued to several exposure model developers to aid the understanding of current systems in a broader sense and to assist the US EPA's effort to develop an approach comparable to other international efforts. A common set of chemicals were prioritized under each current approach. The results are presented herein along with a comparative analysis of the rankings of the chemicals based on metrics of exposure potential or actual exposure estimates. The analysis illustrates the similarities and differences across the domains of information incorporated in each modeling approach. The overall findings indicate a need to reconcile exposures from diffuse, indirect sources (far-field) with exposures from directly, applied chemicals in consumer products or resulting from the presence of a chemical in a microenvironment like a home or vehicle. Additionally, the exposure scenario, including the mode of entry into the environment (i.e. through air, water or sediment) appears to be an important determinant of the level of agreement between modeling approaches. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Comparison of modeling approaches to prioritize chemicals based on estimates of exposure and exposure potential

    Science.gov (United States)

    Mitchell, Jade; Arnot, Jon A.; Jolliet, Olivier; Georgopoulos, Panos G.; Isukapalli, Sastry; Dasgupta, Surajit; Pandian, Muhilan; Wambaugh, John; Egeghy, Peter; Cohen Hubal, Elaine A.; Vallero, Daniel A.

    2014-01-01

    While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecological health outcomes. Recent improvements and advances such as high throughput data gathering, high performance computational capabilities, and predictive chemical inherency methodology make this an opportune time to develop an exposure-based prioritization approach that can systematically utilize and link the asymmetrical bodies of knowledge for hazard and exposure. In response to the US EPA’s need to develop novel approaches and tools for rapidly prioritizing chemicals, a “Challenge” was issued to several exposure model developers to aid the understanding of current systems in a broader sense and to assist the US EPA’s effort to develop an approach comparable to other international efforts. A common set of chemicals were prioritized under each current approach. The results are presented herein along with a comparative analysis of the rankings of the chemicals based on metrics of exposure potential or actual exposure estimates. The analysis illustrates the similarities and differences across the domains of information incorporated in each modeling approach. The overall findings indicate a need to reconcile exposures from diffuse, indirect sources (far-field) with exposures from directly, applied chemicals in consumer products or resulting from the presence of a chemical in a microenvironment like a home or vehicle. Additionally, the exposure scenario, including the mode of entry into the environment (i.e. through air, water or sediment) appears to be an important determinant of the level of agreement between modeling approaches. PMID:23707726

  6. Color vision versus pattern visual evoked potentials in the assessment of subclinical optic pathway involvement in multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Fatih C Gundogan

    2013-01-01

    Full Text Available Background: Optic pathway involvement in multiple sclerosis is frequently the initial sign in the disease process. In most clinical applications, pattern visual evoked potential (PVEP is used in the assessment of optic pathway involvement. Objective: To question the value of PVEP against color vision assessment in the diagnosis of subclinical optic pathway involvement. Materials and Methods: This prospective, cross-sectional study included 20 multiple sclerosis patients without a history of optic neuritis, and 20 healthy control subjects. Farnsworth-Munsell (FM 100-Hue testing and PVEPs to 60-min arc and 15-min arc checks by using Roland-Consult RetiScan® system were performed. P 100 amplitude, P 100 latency in PVEP and total error scores (TES in FM 100-Hue test were assessed. Results: Expanded Disability Status Scale score and the time from diagnosis were 2.21 ± 2.53 (ranging from 0 to 7 and 4.1 ± 4.4 years. MS group showed significantly delayed P 100 latency for both checks (P 0.05 for all. 14 MS patients (70% had an increased TESs in FM-100 Hue, 11 (55% MS patients had delayed P 100 latency and 9 (45% had reduced P 100 amplitude. The areas under the ROC curves were 0.944 for FM-100 Hue test, 0.753 for P 100 latency, and 0.173 for P 100 amplitude. Conclusions: Color vision testing seems to be more sensitive than PVEP in detecting subclinical visual pathway involvement in MS.

  7. Potential of Different Optical and SAR Data in Forest and Land Cover Classification to Support REDD+ MRV

    Directory of Open Access Journals (Sweden)

    Laura Sirro

    2018-06-01

    Full Text Available The applicability of optical and synthetic aperture radar (SAR data for land cover classification to support REDD+ (Reducing Emissions from Deforestation and Forest Degradation MRV (measuring, reporting and verification services was tested on a tropical to sub-tropical test site. The 100 km by 100 km test site was situated in the State of Chiapas in Mexico. Land cover classifications were computed using RapidEye and Landsat TM optical satellite images and ALOS PALSAR L-band and Envisat ASAR C-band images. Identical sample plot data from Kompsat-2 imagery of one-metre spatial resolution were used for the accuracy assessment. The overall accuracy for forest and non-forest classification varied between 95% for the RapidEye classification and 74% for the Envisat ASAR classification. For more detailed land cover classification, the accuracies varied between 89% and 70%, respectively. A combination of Landsat TM and ALOS PALSAR data sets provided only 1% improvement in the overall accuracy. The biases were small in most classifications, varying from practically zero for the Landsat TM based classification to a 7% overestimation of forest area in the Envisat ASAR classification. Considering the pros and cons of the data types, we recommend optical data of 10 m spatial resolution as the primary data source for REDD MRV purposes. The results with L-band SAR data were nearly as accurate as the optical data but considering the present maturity of the imaging systems and image analysis methods, the L-band SAR is recommended as a secondary data source. The C-band SAR clearly has poorer potential than the L-band but it is applicable in stratification for a statistical sampling when other image types are unavailable.

  8. The 2H Electric Dipole Moment in a Separable Potential Approach

    Directory of Open Access Journals (Sweden)

    Afnan I.R.

    2010-04-01

    Full Text Available Measurement of the electric dipole moment (EDM of 2H or of 3He may well come prior to the coveted measurement of the neutron EDM. Exact model calculations for the deuteron are feasible, and we explore here the model dependence of such deuteron EDM calculations. We investigate in a separable potential approach the relationship of the full model calculation to the plane wave approximation, correct an error in an early potential model result, and examine the tensor force aspects of the model results as well as the effect of the short range repulsion found in the realistic, contemporary potential model calculations of Liu and Timmermans. We conclude that, because one-pion exchange dominates the EDM calculation, separable potential model calculations should provide an adequate picture of the 2H EDM until better than 10% measurements are achieved.

  9. Bending localization of nitrous oxide under anharmonicity and Fermi coupling: the dynamical potential approach

    International Nuclear Information System (INIS)

    Zhang Chi; Wu Guo-Zhen; Fang Chao

    2010-01-01

    This paper studies the vibrational nonlinear dynamics of nitrous oxide with Fermi coupling between the symmetric stretching and bending coordinates by classical dynamical potential approach. This is a global approach in the sense that the overall dynamics is evidenced by the classical nonlinear variables such as the fixed points and the focus are on a set of levels instead of individual ones. The dynamics of nitrous oxide is demonstrated to be not so much dependent on the excitation energy. Moreover, the localized bending mode is shown to be ubiquitous in all the energy range studied

  10. Neutron optical potentials in unstable nuclei and the equation of state of asymmetric nuclear matter

    International Nuclear Information System (INIS)

    Oyamatsu, K.; Iida, K.

    2003-01-01

    Neutron single particle potential is one of the basic macroscopic properties to describe structure and reactions of nuclei in nuclear reactors and in the universe. However, the potential is quite uncertain for unstable nuclei primarily because the equation of state (EOS) of asymmetric nuclear matter is not known well. The present authors studied systematically the empirical EOS of asymmetric nuclear matter using a macroscopic nuclear model; about two hundred EOS's having empirically allowed values of L (symmetry energy density derivative coefficient) and K 0 (incompressibility) were obtained from the fittings to masses and radii of stable nuclei. It was suggested that the L value could be determined from global (Z, A) dependence of nuclear radii. In the present study, the single particle potential is examined assuming kinetic energies of non-interacting Fermi gases. The potential in a nucleus can be calculated easily, once the density distribution is solved using the effective nuclear interaction (EOS). Neutron and proton single particle potentials are calculated systematically for 80 Ni using the two hundred EOS's. It is found that the neutron-proton potential difference has clear and appreciable L dependence, while the potential for each species does not show such simple dependence on L. (author)

  11. Trans-eyebrow supraorbital approach in large suprasellar craniopharyngioma surgery in adults: analysis of optic nerve length and extent of tumor resection. Original article.

    Science.gov (United States)

    Prat, Ricardo; Galeano, Inma; Evangelista, Rocío; Pancucci, Giovanni; Guarín, Juliana; Ayuso, Angel; Misra, Mukesh

    2017-05-01

    One of the main drawbacks in the surgery of large craniopharyngiomas is the presence of a prefixed optic chiasm. Our main objective in this study is to compare the predictive value of the optic nerve length and optic chiasm location on large craniopharyngiomas' extent of resection. We retrospectively studied 21 consecutive patients with large craniopharyngiomas who underwent tumor resection through the trans-eyebrow supraorbital approach. Clinical and radiological findings on preoperative MRI were recorded, including the optic chiasm location classified as prefixed, postfixed or normal. We registered the optic nerve length measured intraoperatively prior to tumor removal and confirmed the measurements on preoperative MRI. Using a linear regression model, we calculated a prediction formula of the percentage of the extent of resection as a function of optic nerve length. On preoperative MRI, 15 patients were considered to have an optic chiasm in a normal location, 3 cases had a prefixed chiasm, and the remaining 3 had a postfixed chiasm. In the group with normal optic chiasm location, a wide range of percentage of extent of resection was observed (75-100%). The percentage of extent of resection of large craniopharyngiomas was observed to be dependent on the optic nerve length in a linear regression model (p < 0.0001). According to this model in the normal optic chiasm location group, we obtained an 87% resection in 9-mm optic nerve length patients, a 90.5% resection in 10-mm optic nerve length patients and 100% resection in 11-mm optic nerve length patients. Optic chiasm location provides useful information to predict the percentage of resection in both prefixed and postfixed chiasm patients but not in the normal optic chiasm location group. Optic nerve length was proven to provide a more accurate way to predict the percentage of resection than the optic chiasm location in the normal optic chiasm location group.

  12. Optical imaging for the diagnosis of oral cancer and oral potentially malignant disorders

    Science.gov (United States)

    Yoshida, K.

    2016-03-01

    Optical Imaging is being conducted as a therapeutic non-invasive. Many kinds of the light source are selected for this purpose. Recently the oral cancer screening is conducted by using light-induced tissue autofluorescence examination such as several kinds of handheld devices. However, the mechanism of its action is still not clear. Therefore basic experimental research was conducted. One of auto fluorescence Imaging (AFI) device, VELscopeTM and near-infrared (NIR) fluorescence imaging using ICG-labeled antibody as a probe were compared using oral squamous cell carcinoma (OSCC) mouse models. The experiments revealed that intracutaneous tumor was successfully visualized as low density image by VELscopeTM and high density image by NIR image. In addition, VELscopeTM showed higher sensitivity and lower specificity than that of NIR fluorescence imaging and the sensitivity of identification of carcinoma areas with the VELscopeTM was good results. However, further more studies were needed to enhance the screening and diagnostic uses, sensitivity and specificity for detecting malignant lesions and differentiation from premalignant or benign lesions. Therefore, additional studies were conducted using a new developed near infrared (NIR) fluorescence imaging method targeting podoplanine (PDPN) which consists of indocyanine green (ICG)-labeled anti-human podoplanin antibody as a probe and IVIS imaging system or a handy realtime ICG imaging device that is overexpressed in oral malignant neoplasm to improve imaging for detection of early oral malignant neoplasm. Then evaluated for its sensitivity and specificity for detection of oral malignant neoplasm in xenografted mice model and compared with VELscopeTM. The results revealed that ICG fluorescence imaging method and VELscopeTM had the almost the same sensitivity for detection of oral malignant neoplasm. The current topics of optical imaging about oral malignant neoplasm were reviewed.

  13. Occupational exposure to unburnt tobacco and potential risk of toxic optic neuropathy: A cross-sectional study among beedi rollers in selected rural areas of coastal Karnataka, India.

    Directory of Open Access Journals (Sweden)

    Soujanya Kaup

    Full Text Available Beedi also known as poor man's cigarette is manufactured in almost all major states of India. Beedi workers are exposed to various health risks. There is an increased risk of systemic absorption of tobacco through skin and mucous membrane. The optic nerve is susceptible to damage from several toxic substances including tobacco. This group of disorders is known as toxic optic neuropathy (TON. The association of TON with occupational exposure to unburnt tobacco in beedi rollers has not been explored.Among the beedi rollers in Mangaluru and Bantwal talukas of Dakshina Kannada District, Karnataka, India: to assess the magnitude of potential TON utilizing colour vision and contrast sensitivity as screening tools and to identify the demographic, biological and occupational factors associated with potential TON.A community-based cross-sectional study was conducted from April-Sept 2016 in Mangaluru and Bantwal talukas, of Dakshina Kannada district, Karnataka. Beedi rollers from twelve villages (six from each taluka were included. In each of the selected villages, the investigators identified beedi collection centres and all the eligible beedi rollers were included in the study till the required number of beedi rollers for that village was achieved. Participants were screened at the study site for visual acuity, colour vision and contrast sensitivity and those with abnormal colour and contrast sensitivity in the presence of good visual acuity were considered to have potential TON.A total of 377 beedi rollers were approached; of which 365 consented to take part in the study (response rate: 96.81%. Women constituted the majority of the participants (n = 338, 92.6%. Based on the screening criteria, the prevalence of potential TON was 17.5% (n = 64, 95% CI: 13.5-21.9. On multiple logistic regression analysis, duration of beedi rolling (Adj OR: 1.061; 95% CI 1.015-1.109, p = 0.009, advancing age (Adj OR: 1.096; 95% CI 1.058-1.136, p<0.001 and presence of

  14. A neural network based approach for determination of optical scattering and absorption coefficients of biological tissue

    International Nuclear Information System (INIS)

    Warncke, D; Lewis, E; Leahy, M; Lochmann, S

    2009-01-01

    The propagation of light in biological tissue depends on the absorption and reduced scattering coefficient. The aim of this project is the determination of these two optical properties using spatially resolved reflectance measurements. The sensor system consists of five laser sources at different wavelengths, an optical fibre probe and five photodiodes. For these kinds of measurements it has been shown that an often used solution of the diffusion equation can not be applied. Therefore a neural network is being developed to extract the needed optical properties out of the reflectance data. Data sets for the training, validation and testing process are provided by Monte Carlo Simulations.

  15. Neighborhoods, Schools and Obesity: The Potential for Place-Based Approaches to Reduce Childhood Obesity.

    Directory of Open Access Journals (Sweden)

    Brian Elbel

    Full Text Available A common policy approach to reducing childhood obesity aims to shape the environment in which children spend most of their time: neighborhoods and schools. This paper uses richly detailed data on the body mass index (BMI of all New York City public school students in grades K-8 to assess the potential for place-based approaches to reduce child obesity. We document variation in the prevalence of obesity across NYC public schools and census tracts, and then estimate the extent to which this variation can be explained by differences in individual-level predictors (such as race and household income. Both unadjusted and adjusted variability across neighborhoods and schools suggest place-based policies have the potential to meaningfully reduce child obesity, but under most realistic scenarios the improvement would be modest.

  16. Neighborhoods, Schools and Obesity: The Potential for Place-Based Approaches to Reduce Childhood Obesity

    Science.gov (United States)

    Elbel, Brian; Corcoran, Sean P.; Schwartz, Amy Ellen

    2016-01-01

    A common policy approach to reducing childhood obesity aims to shape the environment in which children spend most of their time: neighborhoods and schools. This paper uses richly detailed data on the body mass index (BMI) of all New York City public school students in grades K-8 to assess the potential for place-based approaches to reduce child obesity. We document variation in the prevalence of obesity across NYC public schools and census tracts, and then estimate the extent to which this variation can be explained by differences in individual-level predictors (such as race and household income). Both unadjusted and adjusted variability across neighborhoods and schools suggest place-based policies have the potential to meaningfully reduce child obesity, but under most realistic scenarios the improvement would be modest. PMID:27309533

  17. Momentum dependence of the imaginary part of the ω- and η{sup '}-nucleus optical potential

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, Stefan; Nanova, Mariana [II. Physikalisches Institut, Justus-Liebig-Universitaet Giessen (Germany); Collaboration: CBELSA/TAPS-Collaboration

    2016-07-01

    The attenuation of ω- and η{sup '}-mesons in cold nuclear matter has been studied in photonuclear reactions on {sup 12}C and {sup 93}Nb for photon energies of 1.2-2.9 GeV, using the tagged photon beam at the ELSA accelerator. ω- and η{sup '}-mesons have been identified via the ω → π{sup 0}γ and η{sup '} → π{sup 0}π{sup 0}η decays, respectively, registered with the CBELSA/TAPS detector system. The momentum dependence of the transparency ratio has been determined for both mesons. Results on the in-medium width of the ω- and η{sup '}-meson and the corresponding meson-nucleon inelastic cross sections will be compared to previous experimental data and recent theoretical predictions. The energy dependence of the imaginary part of the ω- and η{sup '}-nucleus optical potential has been extracted. The higher statistics and finer binning of the present data allow an extrapolation to the production threshold. Corresponding values for the imaginary part of the optical potential will be discussed in view of recent determinations of the ω and η{sup '} scattering lengths.

  18. Silver metaphosphate glass wires inside silica fibers--a new approach for hybrid optical fibers.

    Science.gov (United States)

    Jain, Chhavi; Rodrigues, Bruno P; Wieduwilt, Torsten; Kobelke, Jens; Wondraczek, Lothar; Schmidt, Markus A

    2016-02-22

    Phosphate glasses represent promising candidates for next-generation photonic devices due to their unique characteristics, such as vastly tunable optical properties, and high rare earth solubility. Here we show that silver metaphosphate wires with bulk optical properties and diameters as small as 2 µm can be integrated into silica fibers using pressure-assisted melt filling. By analyzing two types of hybrid metaphosphate-silica fibers, we show that the filled metaphosphate glass has only negligible higher attenuation and a refractive index that is identical to the bulk material. The presented results pave the way towards new fiber-type optical devices relying on metaphosphate glasses, which are promising materials for applications in nonlinear optics, sensing and spectral filtering.

  19. An FBG Optical Approach to Thermal Expansion Measurements under Hydrostatic Pressure.

    Science.gov (United States)

    Rosa, Priscila F S; Thomas, Sean M; Balakirev, Fedor F; Betts, Jon; Seo, Soonbeom; Bauer, Eric D; Thompson, Joe D; Jaime, Marcelo

    2017-11-04

    We report on an optical technique for measuring thermal expansion and magnetostriction at cryogenic temperatures and under applied hydrostatic pressures of 2.0 GPa. Optical fiber Bragg gratings inside a clamp-type pressure chamber are used to measure the strain in a millimeter-sized sample of CeRhIn₅. We describe the simultaneous measurement of two Bragg gratings in a single optical fiber using an optical sensing instrument capable of resolving changes in length [dL/L = (L- L₀)/L₀] on the order of 10 -7 . Our results demonstrate the possibility of performing high-resolution thermal expansion measurements under hydrostatic pressure, a capability previously hindered by the small working volumes typical of pressure cells.

  20. Calculation of far-field scattering from nonspherical particles using a geometrical optics approach

    Science.gov (United States)

    Hovenac, Edward A.

    1991-01-01

    A numerical method was developed using geometrical optics to predict far-field optical scattering from particles that are symmetric about the optic axis. The diffractive component of scattering is calculated and combined with the reflective and refractive components to give the total scattering pattern. The phase terms of the scattered light are calculated as well. Verification of the method was achieved by assuming a spherical particle and comparing the results to Mie scattering theory. Agreement with the Mie theory was excellent in the forward-scattering direction. However, small-amplitude oscillations near the rainbow regions were not observed using the numerical method. Numerical data from spheroidal particles and hemispherical particles are also presented. The use of hemispherical particles as a calibration standard for intensity-type optical particle-sizing instruments is discussed.

  1. Application of quasi-optical approach to construct RF power supply for TeV linear colliders

    International Nuclear Information System (INIS)

    Saldin, E.L.; Sarantsev, V.P.; Schneidmiller, E.A.; Ulyanov, Yu.N.; Yurkov, M.V.

    1995-01-01

    An idea to use a quasi-optical approach for constructing an RF power supply for TeV linear e + e - colliders is developed. The RF source of the proposed scheme is composed of a large number of low-power RF amplifiers commutated by quasi-optical elements. The RF power of this source is transmitted to the accelerating structure of the collider by means of quasi-optical waveguides and mirrors. Such an approach enables one not only to decrease the required peak RF power by several orders of magnitude with respect to the traditional approach based on standard klystron technique, but also to achieve the required level of reliability, as it is based on well-developed technology of serial microwave devices. To illustrate the proposed scheme, a conceptual project of 2x500 GeV X-band collider is considered. Accelerating structure of the collider is of the standard travelling wave type and the RF source is assumed to be composed of 0.7 MW klystrons. All equipment of such a collider is placed in a tunnel of 12x6 m 2 cross section. It is shown that such a collider may be constructed at the present level of accelerator technique. ((orig.))

  2. Transfer map approach to an optical effects of energy degraders on the performance of fragment separators

    International Nuclear Information System (INIS)

    Erdelyi, B.; Bandura, L.; Nolen, J.

    2009-01-01

    A second order analytical and an arbitrary order numerical procedure is developed for the computation of transfer maps of energy degraders. The incorporation of the wedges into the optics of fragment separators for next-generation exotic beam facilities, their optical effects, and the optimization of their performance is studied in detail. It is shown how to place and shape the degraders in the system such that aberrations are minimized and resolving powers are maximized

  3. Transfer map approach to and optical effects of energy degraders in fragment separators

    Directory of Open Access Journals (Sweden)

    B. Erdelyi

    2009-01-01

    Full Text Available A second order analytical and an arbitrary order numerical procedure is developed for the computation of transfer maps of energy degraders. The incorporation of the wedges into the optics of fragment separators for next-generation exotic beam facilities, their optical effects, and the optimization of their performance is studied in detail. It is shown how to place and shape the degraders in the system such that aberrations are minimized and resolving powers are maximized.

  4. The application of the extending symmetry group approach in optical soliton communication

    International Nuclear Information System (INIS)

    Ruan Hangyu; Li Huijun; Chen Yixin

    2005-01-01

    A systematic method which is based on the classical Lie group reduction is used to find the novel exact solution of the nonlinear Schroedinger equation (NLS) with distributed dispersion, nonlinearity and gain or loss. We study the transformations between the standard NLS equation and the NLS equations with distributed dispersion, nonlinearity and gain or loss. Appropriate solitary wave solutions can be applied to discuss soliton propagation in optical fibres, and the amplification and compression of pulses in optical fibre amplifiers

  5. Determining potential locations for biomass valorization using a macro screening approach

    Energy Technology Data Exchange (ETDEWEB)

    Van Dael, M.; Van Passel, S.; Schreurs, E. [Research Group of Environmental Economics, Centre for Environmental Sciences, Hasselt University, Agoralaan Gebouw D, 3590 Diepenbeek (Belgium); Pelkmans, L.; Guisson, R. [VITO, Boeretang 200, 2400 Mol (Belgium); Swinnen, G. [Research Group of Marketing, Hasselt University, Agoralaan Gebouw D, 3590 Diepenbeek (Belgium)

    2012-10-15

    European policy states that by 2020 at least 20% of final energy consumption should come from renewable energy sources. Biomass as a renewable energy source cannot be disregarded in order to attain this target. In this study a macro screening approach is developed to determine potential locations for biomass valorization in a specified region. The approach consists of five steps: (1) criteria determination, (2) data gathering, (3) weight assignment, (4) final score, (5) spatial representation. The resulting outcome provides a first well balanced scan of the possibilities for energy production using regional biomass. This way policy makers and investors can be supported and motivated to study the possibilities of building energy production plants at specific locations in more detail, which can be described as a 'micro-screening'. In our case study the approach is applied to determine the potentially interesting locations to establish a biomass project. The region has been limited to the forty-four communities in the province of Limburg (Belgium). The macro screening approach has shown to be very effective since the amount of interesting locations has been reduced drastically.

  6. Approach of the T-CONT Allocation to Increase the Bandwidth in Passive Optical Networks

    Directory of Open Access Journals (Sweden)

    Z. Bosternak

    2017-12-01

    Full Text Available This paper works with the simulation of T-CONT allocation and delay analysis in passive optical networks PON. Building our networks with the PON technology we can achieve increased data rates, however we need to ensure that the idle gaps between the particular transmissions are minimal. The primary method for the upstream time slot allocation in passive optical networks is via Multi Point Control Protocol. The baseline standard of this protocol clearly defines the use of the REPORT and GATE control messages. The two optical network elements used here, the optical network unit ONT and the optical line termination OLT, located at the central office CO, can be scheduled to allocate the time slots. Using the control messages, a more accurate scheduling algorithm can be developed, hence we can directly improve the utilization of the bandwidth as well. In this work, we introduce the basic topology of the passive optical networks, how PON works and what basic principles of bandwidth allocation have been applied. Subsequently, we suggest a selection of methods for time slot allocation and we make an analysis on the achieved results. Our main focus is on the system load, transfer delay and the analysis of the effectivity.

  7. Determination of the real part of the η{sup '}-Nb optical potential

    Energy Technology Data Exchange (ETDEWEB)

    Nanova, Mariana [II. Physikalisches Institut, Justus-Liebig-Universitaet Giessen (Germany); Collaboration: CBELSA/TAPS-Collaboration

    2016-07-01

    The excitation function and momentum distribution of η{sup '} mesons have been measured in photo production off {sup 93}Nb in the energy range of 1.2-2.9 GeV. The experiment has been performed with the combined Crystal Barrel and MiniTAPS detector system, using tagged photon beams from the ELSA electron accelerator. Information on the sign and magnitude of the real part of the η{sup '}-Nb potential has been extracted from a comparison of the data with model calculations. An attractive potential of -(38 ± 9(stat) ± 12(syst)) MeV depth at normal nuclear matter density is deduced within model uncertainties. This value is consistent with the potential depth of -(37 ± 10(stat) ± 10(syst)) MeV obtained in an earlier measurement for a light nucleus (carbon).

  8. [Linking optical properties of dissolved organic matter with NDMA formation potential in the Huangpu River].

    Science.gov (United States)

    Dong, Qian-Qian; Zhang, Ai; Li, Yong-Mei; Chen, Ling; Huang, Qing-Hui

    2014-03-01

    Surface water samples from the Huangpu River were filtered to measure the UV absorption and fluorescence spectrum. Dissolved organic carbon (DOC), N-nitrosodimethylamine (NDMA), and its formation potential (NDMA-FP) were also analyzed to explore relationships between the properties of dissolved organic matter (DOM) and the formation potential of disinfection byproducts-NDMA in the Huangpu River. The study found that: NDMA-FP concentration increased with the increasing of DOC concentration (r = 0.487, P NDMA-FP concentration had positive relationships with the fluorescence intensity of protein-like substances such as low-molecular-weight (LMW) tyrosine-like and tryptophan-like substances (r = 0.421, P NDMA formation potential increases with the increasing DOM content in the Huangpu River, which is significantly related with the protein-like substances, but decreases with the increasing aromaticity and humification of DOM.

  9. Optic nerve tolerance to single and fractionated radiation simulating radiosurgery: a rabbit model using visual evoked potentials, fundoscopy and histology

    International Nuclear Information System (INIS)

    Bastin, Kenneth; Mehta, Minesh

    1997-01-01

    Purpose/Objective: To develop a rabbit model enabling single or fractionated optic nerve irradiation, measure post-irradiation visual evoked potentials (VEP), fundoscopic and histopathologic changes, and relate different radiation dosing fractions to these measurable physiologic changes. Materials and Methods: Forty male New Zealand white rabbits underwent surgical right orbital prolapse with template-guided optic nerve irradiation using an iridium-192 high dose rate afterloader. Rabbits were randomized into single fraction groups (0 (control), 10, 12.5, 15, 20, and 30 Gy (3 per group); or two fraction groups of 0 (control) 5, 7.5, 10, 15, and 20 Gy (3 per group); or three fractions groups of 10 and 15 Gy (2 per group). Bilateral fundoscopy and pattern-reversal VEPs (0.5 and 1 c/deg, 1 hertz) were performed at 6 and 12 months (mos) following scheduled irradiation. VEP peaks (P1) were measured. Sacrifice and necropsy followed 12 month evaluation, allowing for histological changes. Results: Excluding deaths from anesthesia (2), CNS mite infection (2), sepsis, pyothorax, 'undetermined' and technically non-analyzable VEP recordings, 24 complete rabbit data sets were evaluated. Fundoscopy demonstrated no gross changes at any dose. Histopathology demonstrated generalized optic nerve atrophy without radiation dose correlation. Among single fraction groups, VEP showed a 6 mos post-irradiation P1 prolongation only in the 20 and 30 Gy groups (maximum 67%). At 12 mos lower dose single fraction groups had a prolonged P1 peak. All fractionated groups above 5 Gy x 2 had P1 prolongation times at 6 mos (maximum 46% in the 15 Gy x 3 data set) but by 12 mos these groups had non-measurable, deteriorated VEPs. Correlating VEP P1 latency with the calculated linear quadratic formula (LQM) biologically equivalent dose (BED,α/β=3) for each group demonstrated a general correlation (t-Test P<.001) as shown: Conclusion: Using a rabbit model for selective optic nerve irradiation we conclude

  10. Parity dependence in the optical potential of sd-shell nuclei

    International Nuclear Information System (INIS)

    Ferrero, J.L.; Ruiz, J.A.; Bilwes, B.; Bilwes, R.

    1989-01-01

    Elastic scattering between sd-shell nuclei differing by one, two, three and four nucleons has been measured. The oscillating pattern of the angular distributions, when it is observed, is attributed to the interference between direct elastic scattering and elastic transfer. Explicit DWBA treatment of the elastic transfer or parity dependent real potential analysis allow both a good reproduction of the data. The sign and the importance of the parity potential deduced by fitting the data are in good agreement with the predictions of microscopic calculations in the two centre shell-model

  11. Potential Fluctuations and Localization Effects in CZTS Single Crystals, as Revealed by Optical Spectroscopy

    Science.gov (United States)

    Bleuse, Joël; Ducroquet, Frédérique; Mariette, Henri

    2018-03-01

    Reports on Cu_2 ZnSn(S_x Se_{1-x} )_4 (CZTSSe) solar cell devices all show an open-circuit voltage lower than expected, especially when compared to CuIn_x Ga_{1-x} (S,Se)_2 devices, which reduces their power efficiency and delays their development. A high concentration of intrinsic defects in CZTSSe, and their stabilization through neutral complex formation, which induces some local fluctuations, are at the origin of local energy shifts in the conduction and valence band edges. The implied band tail in Cu_2 ZnSnS_4 is studied in this work by combining three types of optical spectroscopy data: emission spectra compared to photoluminescence excitation spectroscopy, emission spectra as a function of excitation power, and time-resolved photoluminescence spectra. All these data converge to show that both the bandgap and the band tail of localized states just below are dependent on the degree of order/disorder in the Cu/Zn cation sublattice of the quaternary structure: in the more ordered structures, the bandgap increases by about 50 meV, and the energy range of the band tail is decreased from about 110 to 70 meV.

  12. Potential aluminium(III)- and gallium(III)-selective optical sensors based on porphyrazines.

    Science.gov (United States)

    Goslinski, Tomasz; Tykarska, Ewa; Kryjewski, Michal; Osmalek, Tomasz; Sobiak, Stanislaw; Gdaniec, Maria; Dutkiewicz, Zbigniew; Mielcarek, Jadwiga

    2011-01-01

    Porphyrazines possessing non-coordinating alkyl (propyl) and aralkyl (4-tert-butylphenyl) groups in the periphery were studied as optical sensors for a set of mono-, di- and trivalent cations. Investigated porphyrazines in the UV-Vis monitored titrations revealed significant responses towards aluminium and gallium cations, unlike other metal ions studied. Additionally, porphyrazine possessing 4-tert-butylphenyl peripheral substituents showed sensor property towards ruthenium cation and was chosen for further investigation. The presence of isosbestic points in absorption spectra for its titration with aluminium, gallium and ruthenium cations, accompanied by a linear Benesi-Hildebrand plot, proved complex formation. The continuous variation method was used to determine binding stoichiometry in 1:1 porphyrazine-metal ratio. X-Ray studies and density functional theory calculations were employed to investigate octa(4-tert-butylphenyl)porphyrazine structure. The results helped to explain the observed selectivity towards certain ions. Interaction between ion and porphyrazine meso nitrogen in a Lewis acid-Lewis base manner is proposed.

  13. Potential Measurement Errors Due to Image Enlargement in Optical Coherence Tomography Imaging

    Science.gov (United States)

    Uji, Akihito; Murakami, Tomoaki; Muraoka, Yuki; Hosoda, Yoshikatsu; Yoshitake, Shin; Dodo, Yoko; Arichika, Shigeta; Yoshimura, Nagahisa

    2015-01-01

    The effect of interpolation and super-resolution (SR) algorithms on quantitative and qualitative assessments of enlarged optical coherence tomography (OCT) images was investigated in this report. Spectral-domain OCT images from 30 eyes in 30 consecutive patients with diabetic macular edema (DME) and 20 healthy eyes in 20 consecutive volunteers were analyzed. Original image (OR) resolution was reduced by a factor of four. Images were then magnified by a factor of four with and without application of one of the following algorithms: bilinear (BL), bicubic (BC), Lanczos3 (LA), and SR. Differences in peak signal-to-noise ratio (PSNR), retinal nerve fiber layer (RNFL) thickness, photoreceptor layer status, and parallelism (reflects the complexity of photoreceptor layer alterations) were analyzed in each image type. The order of PSNRs from highest to lowest was SR > LA > BC > BL > non-processed enlarged images (NONE). The PSNR was statistically different in all groups. The NONE, BC, and LA images resulted in significantly thicker RNFL measurements than the OR image. In eyes with DME, the photoreceptor layer, which was hardly identifiable in NONE images, became detectable with algorithm application. However, OCT photoreceptor parameters were still assessed as more undetectable than in OR images. Parallelism was not statistically different in OR and NONE images, but other image groups had significantly higher parallelism than OR images. Our results indicated that interpolation and SR algorithms increased OCT image resolution. However, qualitative and quantitative assessments were influenced by algorithm use. Additionally, each algorithm affected the assessments differently. PMID:26024236

  14. Investigation in clinical potential of polarization sensitive optical coherence tomography in laryngeal tumor model study

    Science.gov (United States)

    Zhou, Xin; Oak, Chulho; Ahn, Yeh-Chan; Kim, Sung Won; Tang, Shuo

    2018-02-01

    Polarization-sensitive optical coherence tomography (PS-OCT) is capable of measuring tissue birefringence. It has been widely applied to access the birefringence in tissues such as skin and cartilage. The vocal cord tissue consists of three anatomical layers from the surface to deep inside, the epithelium that contains almost no collagen, the lamina propria that is composed with abundant collagen, and the vocalis muscle layer. Due to the variation in the organization of collagen fibers, the different tissue layers show different tissue birefringence, which can be evaluated by PS-OCT phase retardation measurement. Furthermore, collagen fibers in healthy connective tissues are usually well organized, which provides relatively high birefringence. When the collagen organization is destroyed by diseases such as tumor, the birefringence of the tissue will decrease. In this study, a rabbit laryngeal tumor model with different stages of tumor progression is investigated ex-vivo by PS-OCT. The PS-OCT images show a gradual decrease in birefringence from normal tissue to severe tumor tissue. A phase retardation slope-based analysis is conducted to distinguish the epithelium, lamina propria, and muscle layers, respectively. The phase retardation slope quantifies the birefringence in different layers. The quantitative study provides a more detailed comparison among different stages of the rabbit laryngeal tumor model. The PS-OCT result is validated by the corresponding histology images of the same samples.

  15. Potential for efficient frequency conversion at high average power using solid state nonlinear optical materials

    International Nuclear Information System (INIS)

    Eimerl, D.

    1985-01-01

    High-average-power frequency conversion using solid state nonlinear materials is discussed. Recent laboratory experience and new developments in design concepts show that current technology, a few tens of watts, may be extended by several orders of magnitude. For example, using KD*P, efficient doubling (>70%) of Nd:YAG at average powers approaching 100 KW is possible; and for doubling to the blue or ultraviolet regions, the average power may approach 1 MW. Configurations using segmented apertures permit essentially unlimited scaling of average power. High average power is achieved by configuring the nonlinear material as a set of thin plates with a large ratio of surface area to volume and by cooling the exposed surfaces with a flowing gas. The design and material fabrication of such a harmonic generator are well within current technology

  16. Axonal electrovisiogram as an electrophysiological test to evaluate optic nerve and inner retina electrical potentials: findings in normal subjects

    Directory of Open Access Journals (Sweden)

    Wener Passarinho Cella

    2011-02-01

    Full Text Available PURPOSES: To standardize and validate the technique of axonal electrovisiogram (AxEvg, defining its normative values and parameters and characterizing its findings in normal individuals. METHODS: We enrolled 140 normal individuals (280 eyes divided into seven groups according to age, each one with 10 males and 10 females. The technique was based on monocular visual stimulation by a 0 dB intensity bright flash on Ganzfeld bowl at a presentation rate of 1.4 Hz. Golden cup electrodes were used and electrical waves were acquired after artifact rejection. For each amplitude and implicit time peak we calculated the mean, median, pattern deviation, minimum and maximum values and 95% confidence interval. RESULTS: Monocular visual stimulation with bright flash under mesopic conditions was the standard technical procedure established. The normal AxEvg waveform consists of an initial positive wave (named P1, with mean amplitude of 2.0 mV and mean implicit time peak of 23.1 ms followed by a negative wave (named N1, with mean amplitude of -3.9 mV and mean implicit time peak of 41.4 ms. No significant differences were observed between males and females or between right and left eyes, but there was an increased P1 and N1 implicit time peaks according to age. Implicit time characteristics suggest that P1 wave represents an optic nerve electrical potential and N1 wave represents an inner retinal layers potential. CONCLUSIONS: AxEvg can be considered a pre-chiasmatic visual evoked potential capable to reliably record the electrical activity of optic nerve and inner retina. The findings suggest that AxEvg may be useful as an electrophysiological test in the diagnosis of neuroretinal diseases.

  17. Observation of superconducting fluxons by transmission electron microscopy: A Fourier space approach to calculate the electron optical phase shifts and images

    International Nuclear Information System (INIS)

    Beleggia, M.; Pozzi, G.

    2001-01-01

    An approach is presented for the calculation of the electron optical phase shift experienced by high-energy electrons in a transmission electron microscope, when they interact with the magnetic field associated with superconducting fluxons in a thin specimen tilted with respect to the beam. It is shown that by decomposing the vector potential in its Fourier components and by calculating the phase shift of each component separately, it is possible to obtain the Fourier transform of the electron optical phase shift, which can be inverted either analytically or numerically. It will be shown how this method can be used to recover the result, previously obtained by the real-space approach, relative to the case of a straight flux tube perpendicular to the specimen surfaces. Then the method is applied to the case of a London fluxon in a thin film, where the bending and the broadening of the magnetic-field lines due to the finite specimen thickness are now correctly taken into account and not treated approximately by means of a parabolic fit. Finally, it will be shown how simple models for the pancake structure of the fluxon can be analyzed within this framework and the main features of electron transmission images predicted

  18. A Simple Approach to Dynamic Optimisation of Flexible Optical Networks with Practical Application

    Directory of Open Access Journals (Sweden)

    Vic Grout

    2017-05-01

    Full Text Available This paper provides an initial introduction to, and definition of, the ‘Dynamically Powered Relays for a Flexible Optical Network’ (DPR-FON problem for opto-electro-optical (OEO regenerators used in optical networks. In such networks, optical transmission parameters can be varied dynamically as traffic patterns change. This will provide different bandwidths, but also change the regeneration limits as a result. To support this flexibility, OEOs (‘relays’ may be switched on and off as required, thus saving power. DPR-FON is shown to be NP-complete; consequently, solving such a dynamic problem in real-time requires a fast heuristic capable of delivering an acceptable approximation to the optimal configuration with low complexity. In this paper, just such an algorithm is developed, implemented, and evaluated against more computationally-demanding alternatives for two known cases. A number of real-world extensions are considered as the paper develops, combining to produce the ‘Generalised Dynamically Powered Relays for a Flexible Optical Network’ (GDPR-FON problem. This, too, is analysed and an associated fast heuristic proposed, along with an exploration of the further research that is required.

  19. Optics industry in Spain: a cluster approach to increasing competitiveness through collaboration in R&D and innovation

    Science.gov (United States)

    Cifuentes, Andrés F.

    2011-10-01

    The optics industry in Spain pooled together to create the Southern European Cluster in Photonics and Optics - SECPhO, founded in April 2009, with the mission to help the sector increase competitiveness, specially through collaboration. From 10 founding members, SECPhO no incorporates over 40 members, which is nearly 40% of the optics industry in the region. From the beginning of operations the cluster has focused on three strategic challenges: R&D+i and Productivity, Visibility and Internationalization, and Betterment and Retention of Talent. A brief summary of the clusters activities is given. In this article, the focus will be on R&D and innovation, through industry driven collaborative initiatives and the tools and actions that lead to successful partnerships. Topics discussed in this work are will be a cluster's role in promoting strategic change, the value chain approach to partnerships, international collaboration in projects and specific cluster activities. Some practical examples of initiatives relating to effective collaboration are described, focusing on one of the mayor challenges of our time: the greening of the planet. Examples will be addressed in smart cities, efficient LASER applications and lightweight optical sensors for civil security. In all cases the collaboration between the public and private sectors is shown.

  20. Frequency-Dependent Streaming Potential of Porous Media—Part 1: Experimental Approaches and Apparatus Design

    Directory of Open Access Journals (Sweden)

    P. W. J. Glover

    2012-01-01

    Full Text Available Electrokinetic phenomena link fluid flow and electrical flow in porous and fractured media such that a hydraulic flow will generate an electrical current and vice versa. Such a link is likely to be extremely useful, especially in the development of the electroseismic method. However, surprisingly few experimental measurements have been carried out, particularly as a function of frequency because of their difficulty. Here we have considered six different approaches to make laboratory determinations of the frequency-dependent streaming potential coefficient. In each case, we have analyzed the mechanical, electrical, and other technical difficulties involved in each method. We conclude that the electromagnetic drive is currently the only approach that is practicable, while the piezoelectric drive may be useful for low permeability samples and at specified high frequencies. We have used the electro-magnetic drive approach to design, build, and test an apparatus for measuring the streaming potential coefficient of unconsolidated and disaggregated samples such as sands, gravels, and soils with a diameter of 25.4 mm and lengths between 50 mm and 300 mm.

  1. A Neural Network Approach to Infer Optical Depth of Thick Ice Clouds at Night

    Science.gov (United States)

    Minnis, P.; Hong, G.; Sun-Mack, S.; Chen, Yan; Smith, W. L., Jr.

    2016-01-01

    One of the roadblocks to continuously monitoring cloud properties is the tendency of clouds to become optically black at cloud optical depths (COD) of 6 or less. This constraint dramatically reduces the quantitative information content at night. A recent study found that because of their diffuse nature, ice clouds remain optically gray, to some extent, up to COD of 100 at certain wavelengths. Taking advantage of this weak dependency and the availability of COD retrievals from CloudSat, an artificial neural network algorithm was developed to estimate COD values up to 70 from common satellite imager infrared channels. The method was trained using matched 2007 CloudSat and Aqua MODIS data and is tested using similar data from 2008. The results show a significant improvement over the use of default values at night with high correlation. This paper summarizes the results and suggests paths for future improvement.

  2. Hiding objects and creating illusions above a carpet filter using a Fourier optics approach.

    Science.gov (United States)

    Wu, Kedi; Wang, Guo Ping

    2010-09-13

    Invisibility carpet cloaks are usually used to hide an object beneath carpet. In this paper we propose and demonstrate a carpet filter to hide objects and create illusions above the filter by using a Fourier optics method. Instead of using transformation optics, we get electromagnetic parameters of the filter by optical transfer functions, which play the role of modulating the propagation of the scattering angular spectrum directly from an object above the filter. By further adding a functional layer onto the filter, we can even camouflage the object so that it appears to be a different object. The analytical results are confirmed by numerical simulations. Our method is completely different from the current coordinate transfer method and may provide another point of view to more clearly understand the mechanism of invisibility cloaks.

  3. A new approach to optic disc detection in human retinal images using the firefly algorithm.

    Science.gov (United States)

    Rahebi, Javad; Hardalaç, Fırat

    2016-03-01

    There are various methods and algorithms to detect the optic discs in retinal images. In recent years, much attention has been given to the utilization of the intelligent algorithms. In this paper, we present a new automated method of optic disc detection in human retinal images using the firefly algorithm. The firefly intelligent algorithm is an emerging intelligent algorithm that was inspired by the social behavior of fireflies. The population in this algorithm includes the fireflies, each of which has a specific rate of lighting or fitness. In this method, the insects are compared two by two, and the less attractive insects can be observed to move toward the more attractive insects. Finally, one of the insects is selected as the most attractive, and this insect presents the optimum response to the problem in question. Here, we used the light intensity of the pixels of the retinal image pixels instead of firefly lightings. The movement of these insects due to local fluctuations produces different light intensity values in the images. Because the optic disc is the brightest area in the retinal images, all of the insects move toward brightest area and thus specify the location of the optic disc in the image. The results of implementation show that proposed algorithm could acquire an accuracy rate of 100 % in DRIVE dataset, 95 % in STARE dataset, and 94.38 % in DiaRetDB1 dataset. The results of implementation reveal high capability and accuracy of proposed algorithm in the detection of the optic disc from retinal images. Also, recorded required time for the detection of the optic disc in these images is 2.13 s for DRIVE dataset, 2.81 s for STARE dataset, and 3.52 s for DiaRetDB1 dataset accordingly. These time values are average value.

  4. A MULTI-OBJECTIVE APPROACH TO THE EVALUATION OF INNOVATIVE POTENTIAL OF THE TOURISM INDUSTRY ORGANIZATIONS

    Directory of Open Access Journals (Sweden)

    Tat’yana Pavlovna Levchenko

    2018-02-01

    Full Text Available Speaking about innovation in the tourism industry and hotel business, in particular, it usually means events of a systemic nature, with quality novelty, aimed at achieving positive changes, stable functioning and dynamic development. Along with general economic factors that determine the uneven demand for services of hospitality, it is explained by the sharp increase in dependence of their tourism and recreational opportunities from innovative potential (IP, capability of adapting to challenging competitive environment. The article considers a multi-objective approach to the study of the innovative potential of the tourism industry organizations. Its essence lies in the fact that the choice of the structural elements from the point of view of their value and importance (in any combination cannot be established a priori, without sufficient objective analysis on some of the more important criteria for achieving the goals. A diagnostic analysis and evaluation of the innovation potential of several hotel organizations from the standpoint of a multi-purpose approach is performed.

  5. Pseudodynamic systems approach based on a quadratic approximation of update equations for diffuse optical tomography.

    Science.gov (United States)

    Biswas, Samir Kumar; Kanhirodan, Rajan; Vasu, Ram Mohan; Roy, Debasish

    2011-08-01

    We explore a pseudodynamic form of the quadratic parameter update equation for diffuse optical tomographic reconstruction from noisy data. A few explicit and implicit strategies for obtaining the parameter updates via a semianalytical integration of the pseudodynamic equations are proposed. Despite the ill-posedness of the inverse problem associated with diffuse optical tomography, adoption of the quadratic update scheme combined with the pseudotime integration appears not only to yield higher convergence, but also a muted sensitivity to the regularization parameters, which include the pseudotime step size for integration. These observations are validated through reconstructions with both numerically generated and experimentally acquired data.

  6. The effects of a geometrical size, external electric fields and impurity on the optical gain of a quantum dot laser with a semi-parabolic spherical well potential

    Science.gov (United States)

    Owji, Erfan; Keshavarz, Alireza; Mokhtari, Hosein

    2017-03-01

    In this paper, a GaAs / Alx Ga1-x As quantum dot laser with a semi-parabolic spherical well potential is assumed. By using Runge-Kutta method the eigenenergies and the eigenstates of valence and conduct bands are obtained. The effects of geometrical sizes, external electric fields and hydrogen impurity on the different electronic transitions of the optical gain are studied. The results show that the optical gain peak increases and red-shifts, by increasing the width of well or barrier, while more increasing of the width causes blue-shift and decreases it. The hydrogen impurity decreases the optical gain peak and blue-shifts it. Also, the increasing of the external electric fields cause to increase the peak of the optical gain, and (blue) red shift it. Finally, the optical gain for 1s-1s and 2s-1s transitions is prominent, while it is so weak for other transitions.

  7. Optical fiber taste sensors using potential sensitive dye coatings. Makuden'i kanjusei shikisomaku wo mochiita hikari fiber mikaku sensor

    Energy Technology Data Exchange (ETDEWEB)

    Yamakawa, S.; Yamaguchi, A. (Toyama National College of Maritime Technology, Toyama (Japan))

    1992-12-20

    The present paper proposes a new taste recognition system using optical response patterns from multi-channel optical fiber sensors having potential sensitive dye coatings. It was found that the sensors give large changes in optical absorption spectra of the dyes when they are immersed in various taste solutions. Consequently, it was shown that the sensors can be used as a taste sensor. Six dyes, which give large changes in dye absorption, were selected from twenty dyes and used for six-channel optical fiber taste sensors array. The absorption spectra change data were processed by multiple discriminant analysis and neural networks using back-propagation algorithm. From the analytical results, it was demonstrated that salty (NaCl), bitter (quinidine), sweet (sucrose), sour (HCl), and umami (sodium glutamate) substances can be recognized from each other by using the optical taste sensor system. 11 refs., 8 figs., 2 tabs.

  8. Gadolinium(III-DOTA Complex Functionalized with BODIPY as a Potential Bimodal Contrast Agent for MRI and Optical Imaging

    Directory of Open Access Journals (Sweden)

    Matthias Ceulemans

    2015-11-01

    Full Text Available The synthesis and characterization of a novel gadolinium(III DOTA complex functionalized with a boron-dipyrromethene derivative (BODIPY is described. The assembly of the complex relies on azide diazotransfer chemistry in a copper tube flow reactor. The azide thus formed is coupled directly with an alkyne via click chemistry, resulting into a paramagnetic and luminescent gadolinium(III complex. Luminescent data and relaxometric properties of the complex have been evaluated, suggesting the potential applicability of the complexes as a bimodal contrast agent for magnetic resonance and optical imaging. The complex displays a bright emission at 523 nm with an absorption maximum of 507 nm and high quantum yields of up to 83% in water. The proton relaxivity of the complex measured at 310 K and at frequencies of 20 and 60 MHz had the values of 3.9 and 3.6 s−1·mM−1, respectively.

  9. More Than a Potential Hazard—Approaching Risks from a Social-Ecological Perspective

    Directory of Open Access Journals (Sweden)

    Carolin Völker

    2017-06-01

    Full Text Available Risks have been classically understood as a probability of damage or a potential hazard resulting in appropriate management strategies. However, research on environmental issues such as pollutants in the aquatic environment or the impacts of climate change have shown that classical management approaches do not sufficiently cover these interactions between society and nature. There have been several attempts to develop interdisciplinary approaches to risk that include natural as well as social science contributions. In this paper, the authors aim at developing a social-ecological perspective on risk by drawing on the concept of societal relations to nature and the model of provisioning systems. This perspective is used to analyze four cases, pharmaceuticals, microplastics, semicentralized water infrastructures and forest management, with regard to risk identification, assessment and management. Finally, the paper aims at developing a perspective on risks which takes into account non-intended side-effects, system interdependencies and uncertainty.

  10. Nucleation theory in Langevin's approach and lifetime of a Brownian particle in potential wells.

    Science.gov (United States)

    Alekseechkin, N V

    2008-07-14

    The multivariable theory of nucleation suggested by Alekseechkin [J. Chem. Phys. 124, 124512 (2006)] is further developed in the context of Langevin's approach. The use of this approach essentially enhances the capability of the nucleation theory, because it makes possible to consider the cases of small friction which are not taken into account by the classical Zel'dovich-Frenkel theory and its multivariable extensions. The procedure for the phenomenological determination of the nucleation parameters is described. Using the similarity of the Kramers model with that of nucleation, the lifetime of a Brownian particle in potential wells in various dimensionalities is calculated with the help of the expression for the steady state nucleation rate.

  11. Constraints on the α+nucleus optical-model potential via α-induced reaction studies on 108Cd

    Directory of Open Access Journals (Sweden)

    P. Scholz

    2016-10-01

    Full Text Available A big part in understanding the nucleosynthesis of heavy nuclei is a proper description of the effective interaction between an α-particle and a target nucleus. Information about the so-called α+nucleus optical-model potential is achieved by precise cross-section measurements at sub-Coulomb energies aiming to constrain the theoretical models for the nuclear physics input-parameters. The cross sections of the 108Cd(α,γ and 108Cd(α,n reaction have been measured for the first time close to the astrophysically relevant energy region via the in-beam method at the high-efficiency γ-ray spectrometer HORUS and via the activation technique at the Cologne Clover Counting Setup at the Institute for Nuclear Physics in Cologne, Germany. Comparisons between experimental results and theoretical predictions calculated in the scope of the Hauser–Feshbach statistical model confirm the need for a exponentially decreasing imaginary part of the potential. Moreover, it is shown that the results presented here together with already published data indicate that a systematic investigation of the real part of the potential could help to further improve the understanding of reactions involving α-particles.

  12. A dispersive optical model potential for nucleon induced reactions on 238U and 232Th nuclei with full coupling

    Directory of Open Access Journals (Sweden)

    Chiba Satoshi

    2013-03-01

    Full Text Available A dispersive coupled-channel optical model potential (DCCOMP that couples the ground-state rotational and low-lying vibrational bands of 238U and 232Th nuclei is studied. The derived DCCOMP couples almost all excited levels below 1 MeV of excitation energy of the corresponding even-even actinides. The ground state, octupole, beta, gamma, and non-axial bands are coupled. The first two isobar analogue states (IAS populated in the quasi-elastic (p,n reaction are also coupled in the proton induced calculation, making the potential approximately Lane consistent. The coupled-channel potential is based on a soft-rotor description of the target nucleus structure, where dynamic vibrations are considered as perturbations of the rigid rotor underlying structure. Matrix elements required to use the proposed structure model in Tamura coupled-channel scheme are derived. Calculated ratio R(U238/Th232 of the total cross-section difference to the averaged σT for 238U and 232Th nuclei is shown to be in excellent agreement with measured data.

  13. Optical and electrical properties of hydrided palladium thin films studied by an inversion approach from transmittance measurements

    International Nuclear Information System (INIS)

    Vargas, W.E.; Rojas, I.; Azofeifa, D.E.; Clark, N.

    2006-01-01

    Palladium (Pd) thin films have been deposited by electron beam evaporation, and exposed to increasing hydrogen pressures. Transmittance spectra in the range of visible light have been measured to obtain from them, by means of a spectral projected gradient method, the wavelength dependence of the dielectric function. The decreasing metallic character of Pd with hydrogen absorption is displayed. This effect is more pronounced when Pd is deposited on metallic substrates, and there is a correlation with an increase in the effective polarization of the core electrons determining the optical dielectric constant value. Another optimization approach is devised to separate the contribution of the free carriers and of the interband transitions to the optical conductivity and to the dielectric function. Very good agreement is found between the optimized parameters characterizing the free carrier contribution and the corresponding values reported in the literature and obtained by independent experimental methods

  14. Super-resolution nanofabrication with metal-ion doped hybrid material through an optical dual-beam approach

    International Nuclear Information System (INIS)

    Cao, Yaoyu; Li, Xiangping; Gu, Min

    2014-01-01

    We apply an optical dual-beam approach to a metal-ion doped hybrid material to achieve nanofeatures beyond the optical diffraction limit. By spatially inhibiting the photoreduction and the photopolymerization, we realize a nano-line, consisting of polymer matrix and in-situ generated gold nanoparticles, with a lateral size of sub 100 nm, corresponding to a factor of 7 improvement compared to the diffraction limit. With the existence of gold nanoparticles, a plasmon enhanced super-resolution fabrication mechanism in the hybrid material is observed, which benefits in a further reduction in size of the fabricated feature. The demonstrated nanofeature in hybrid materials paves the way for realizing functional nanostructures

  15. Electronic excitation of atoms and molecules by electron impact in a linear algebraic, separable potential approach

    International Nuclear Information System (INIS)

    Collins, L.A.; Schneider, B.I.

    1984-01-01

    The linear algebraic, separable potential approach is applied to the electronic excitation of atoms and molecules by electron impact. By representing the exchange and off-diagonal direct terms on a basis, the standard set of coupled inelastic equations is reduced to a set of elastic inhomogeneous equations. The procedure greatly simplifies the formulation by allowing a large portion of the problem to be handled by standard bound-state techniques and by greatly reducing the order of the scattering equations that must be solved. Application is made to the excitation of atomic hydrogen in the three-state close-coupling (1s, 2s, 2p) approximation. (author)

  16. Instanton Approach to the Langevin Motion of a Particle in a Random Potential

    International Nuclear Information System (INIS)

    Lopatin, A. V.; Vinokur, V. M.

    2001-01-01

    We develop an instanton approach to the nonequilibrium dynamics in one-dimensional random environments. The long time behavior is controlled by rare fluctuations of the disorder potential and, accordingly, by the tail of the distribution function for the time a particle needs to propagate along the system (the delay time). The proposed method allows us to find the tail of the delay time distribution function and delay time moments, providing thus an exact description of the long time dynamics. We analyze arbitrary environments covering different types of glassy dynamics: dynamics in a short-range random field, creep, and Sinai's motion

  17. α decay properties of 297Og within the two-potential approach

    Science.gov (United States)

    Deng, Jun-Gang; Cheng, Jun-Hao; Zheng, Bo; Li, Xiao-Hua

    2017-12-01

    The α decay half-life of the unknown nucleus 297Og is predicted within the two-potential approach, and α preformation probabilities of 64 odd-A nuclei in the region of proton numbers 82 Education Bureau of Hunan Province, China (15A159), the Natural Science Foundation of Hunan Province, China (2015JJ3103, 2015JJ2121), the Innovation Group of Nuclear and Particle Physics in USC, the Shandong Province Natural Science Foundation, China (ZR2015AQ007) and Hunan Provincial Innovation Foundation For Postgraduate (CX2017B536)

  18. Solvated electron: criticism of a suggested correlation of chemical potential with optical absorption energy

    International Nuclear Information System (INIS)

    Farhataziz, M.

    1984-01-01

    A recent theoretical treatment of the absorption spectrum of the solvated electron, e - sub(s), maintains that rigorously μ 0 >= -0.75 Esub(av), which gives empirical relationship, μ 0 >= -(0.93 +- 0.02)Esub(max). For e - sub(s) in a particular solvent at a temperature and pressure, μ 0 , Esub(av) and Esub(max) are standard chemical potential, average energy of the absorption spectrum and the energy at the absorption maximum respectively. The temperature and pressure effects on the absorption spectrum of e - sub(s) in water and liquid ammonia do not support the equality sign in the above cited relationships. The implications of inequality expressed above are discussed for e - sub(s) in water and liquid ammonia. (author)

  19. GABAergic transmission and chloride equilibrium potential are not modulated by pyruvate in the developing optic tectum of Xenopus laevis tadpoles.

    Directory of Open Access Journals (Sweden)

    Arseny S Khakhalin

    Full Text Available In the developing mammalian brain, gamma-aminobutyric acid (GABA is thought to play an excitatory rather than an inhibitory role due to high levels of intracellular Cl(- in immature neurons. This idea, however, has been questioned by recent studies which suggest that glucose-based artificial cerebrospinal fluid (ACSF may be inadequate for experiments on immature and developing brains. These studies suggest that immature neurons may require alternative energy sources, such as lactate or pyruvate. Lack of these other energy sources is thought to result in artificially high intracellular Cl(- concentrations, and therefore a more depolarized GABA receptor (GABAR reversal potential. Since glucose metabolism can vary widely among different species, it is important to test the effects of these alternative energy sources on different experimental preparations. We tested whether pyruvate affects GABAergic transmission in isolated brains of developing wild type Xenopus tadpoles in vitro by recording the responsiveness of tectal neurons to optic nerve stimulation, and by measuring currents evoked by local GABA application in a gramicidin perforated patch configuration. We found that, in contrast with previously reported results, the reversal potential for GABAR-mediated currents does not change significantly between developmental stages 45 and 49. Partial substitution of glucose by pyruvate had only minor effects on both the GABA reversal potential, and the responsiveness of tectal neurons at stages 45 and 49. Total depletion of energy sources from the ACSF did not affect neural responsiveness. We also report a strong spatial gradient in GABA reversal potential, with immature cells adjacent to the lateral and caudal proliferative zones having more positive reversal potentials. We conclude that in this experimental preparation standard glucose-based ACSF is an appropriate extracellular media for in vitro experiments.

  20. Magnetic and optical properties of carbon and silicon decorated free standing buckled germanene: A DFT approach

    Science.gov (United States)

    Dhar, Namrata; Jana, Debnarayan

    2018-04-01

    Ab initio magnetic and optical properties of group IV elements (carbon (C) and silicon (Si)) decorated free standing (FS) buckled germanene systems have been employed theoretically. Our study elucidates that, decoration of these elements in proper sites with suitable concentrations form dynamically stable configurations. Band structure is modified due to decoration of these atoms in Ge-nanosheet and pristine semi-metallic germanene undergoes to semiconductors with a finite amount of bandgap. Interestingly, this bandgap value meets closely the requirement of gap for field effect transistor (FET) applications. Moreover, significant magnetic moment is induced in non-magnetic germanene for C decorated structure and ground state in anti-ferromagnetic in nature for this structure. Along with magnetic property, optical properties like dielectric functions, optical absorption, electron energy loss spectra (EELS), refractive index and reflectivity of these systems have also been investigated. Maximum number of plasma frequencies appear for Si decorated configuration considering both parallel and perpendicular polarizations. In addition, birefringence characteristics of these configurations have also been studied as it is an important parameter in various applications of optical devices, liquid crystal displays, light modulators etc.

  1. Optical approach to thermopower and conductivity measurements in thin-film semiconductors

    International Nuclear Information System (INIS)

    Dersch, H.; Amer, N.M.

    1984-01-01

    An optical beam deflection technique is applied to measure the Joule and Peltier heat generated by electric currents through thin-film semiconductors. The method yields a spatially resolved conductivity profile and allows the determination of Peltier coefficients. Results obtained on doped hydrogenated amorphous silicon films are presented

  2. Exact solution of the optical response of thick slabs in the discrete dipole approach".

    NARCIS (Netherlands)

    Poppe, G.P.M.; Poppe, G.P.M.; Wijers, Christianus M.J.

    1990-01-01

    The recently developed double cell technique, which describes the optical response of an arbitrary semi-infinite dielectric crystal taking into account internal field effects, is extended to include the response of thick slabs. The surface sensitivity of the first technique is fully retained. The

  3. A combined variational-topological approach for dispersion-managed solitons in optical fibers

    Czech Academy of Sciences Publication Activity Database

    Hakl, Robert; Torres, P.J.

    2011-01-01

    Roč. 62, č. 2 (2011), s. 245-266 ISSN 0044-2275 Institutional research plan: CEZ:AV0Z10190503 Keywords : optical soliton * Schrödinger equation * singular equation * periodic solution * upper and lower function Subject RIV: BA - General Mathematics Impact factor: 0.951, year: 2011 http://www.springerlink.com/content/y1534p553r530451/

  4. Interference of Light in a Michelson-Morley Interferometer: A Quantum Optical Approach

    Directory of Open Access Journals (Sweden)

    Ø. Langangen

    2012-01-01

    Full Text Available The temporal coherence interference properties of light as revealed by single detector intensity measurements in a Michelson-Morley interferometer (MMI is often described in terms of classical optics. We show, in a pedagogical manner, how such features of light also can be understood in terms of a more general quantum-optics framework. If a thermal reference source is used in the MMI local oscillator port in combination with a thermal source in the signal port, the interference pattern revealed by single detector intensity measurements shows a distinctive dependence on the differences in the temperature of the two sources. A related method has actually been used to perform high-precision measurements of the cosmic microwave background radiation. The general quantum-optics framework allows us to consider any initial quantum state. As an example, we consider the interference of single photons as a tool to determine the peak angular-frequency of a single-photon pulse interfering with a single-photon reference pulse. A similar consideration for laser pulses, in terms of coherent states, leads to a different response in the detector. The MMI experimental setup is therefore an example of an optical device where one, in terms of intensity measurements, can exhibit the difference between classical and quantum-mechanical light.

  5. Active Learning of Geometrical Optics in High School: The ALOP Approach

    Science.gov (United States)

    Alborch, Alejandra; Pandiella, Susana; Benegas, Julio

    2017-01-01

    A group comparison experiment of two high school classes with pre and post instruction testing has been carried out to study the suitability and advantages of using the active learning of optics and photonics (ALOP) curricula in high schools of developing countries. Two parallel, mixed gender, 12th grade classes of a high school run by the local…

  6. Construction of Ray Diagrams in Geometrical Optics: A Media-Focused Approach

    Science.gov (United States)

    Santana, Alejandro; Rodriguez, Yohany; Gomez, Edgar A.

    2012-01-01

    Ray diagrams offer a powerful framework for understanding and characterizing many properties of optical systems, such as images and magnifications. However, this construction also introduces many conceptual hurdles for students. The idea of representing the propagation of waves by means of a light ray, which is a line or curve perpendicular to the…

  7. Educational games for brain health: revealing their unexplored potential through a neurocognitive approach

    Directory of Open Access Journals (Sweden)

    Patrick eFissler

    2015-07-01

    Full Text Available Educational games link the motivational nature of games with learning of knowledge and skills. Here, we go beyond effects on these learning outcomes. We review two lines of evidence which indicate the currently unexplored potential of educational games to promote brain health: First, gaming with specific neurocognitive demands (e.g., executive control, and second, educational learning experiences (e.g., studying foreign languages improve brain health markers. These markers include cognitive ability, brain function, and brain structure. As educational games allow the combination of specific neurocognitive demands with educational learning experiences, they seem to be optimally suited for promoting brain health. We propose a neurocognitive approach to reveal this unexplored potential of educational games in future research.

  8. An approach to delineate groundwater recharge potential sites in Ambalantota, Sri Lanka using GIS techniques

    Directory of Open Access Journals (Sweden)

    I.P. Senanayake

    2016-01-01

    Full Text Available The demand for fresh water in Hambantota District, Sri Lanka is rapidly increasing with the enormous amount of ongoing development projects in the region. Nevertheless, the district experiences periodic water stress conditions due to seasonal precipitation patterns and scarcity of surface water resources. Therefore, management of available groundwater resources is critical, to fulfil potable water requirements in the area. However, exploitation of groundwater should be carried out together with artificial recharging in order to maintain the long term sustainability of water resources. In this study, a GIS approach was used to delineate potential artificial recharge sites in Ambalantota area within Hambantota. Influential thematic layers such as rainfall, lineament, slope, drainage, land use/land cover, lithology, geomorphology and soil characteristics were integrated by using a weighted linear combination method. Results of the study reveal high to moderate groundwater recharge potential in approximately 49% of Ambalantota area.

  9. Technical Potential Assessment for the Renewable Energy Zone (REZ) Process: A GIS-Based Approach

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Nathan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Roberts, Billy J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-05

    Geographic Information Systems (GIS)-based energy resource and technical potential assessments identify areas capable of supporting high levels of renewable energy (RE) development as part of a Renewable Energy Zone (REZ) Transmission Planning process. This document expands on the REZ Process to aid practitioners in conducting GIS-based RE resource and technical potential assessments. The REZ process is an approach to plan, approve, and build transmission infrastructure that connects REZs - geographic areas that have high-quality RE resources, suitable topography and land-use designations, and demonstrated developer interest - to the power system. The REZ process helps to increase the share of solar photovoltaic (PV), wind, and other resources while also maintaining reliability and economics.

  10. Market potential of nanoremediation in Europe - Market drivers and interventions identified in a deliberative scenario approach.

    Science.gov (United States)

    Bartke, Stephan; Hagemann, Nina; Harries, Nicola; Hauck, Jennifer; Bardos, Paul

    2018-04-01

    A deliberate expert-based scenario approach is applied to better understand the likely determinants of the evolution of the market for nanoparticles use in remediation in Europe until 2025. An initial set of factors had been obtained from a literature review and was complemented by a workshop and key-informant interviews. In further expert engaging formats - focus groups, workshops, conferences, surveys - this initial set of factors was condensed and engaged experts scored the factors regarding their importance for being likely to influence the market development. An interaction matrix was obtained identifying the factors being most active in shaping the market development in Europe by 2025, namely "Science-Policy-Interface" and "Validated information on nanoparticle application potential". Based on these, potential scenarios were determined and development of factors discussed. Conclusions are offered on achievable interventions to enhance nanoremediation deployment. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Structural, thermal, optical properties and cytotoxicity of PMMA/ZnO fibers and films: Potential application in tissue engineering

    International Nuclear Information System (INIS)

    Balen, Rodrigo; Vidotto da Costa, Wilian; Lara Andrade, Jéssica de; Piai, Juliana Francis; Muniz, Edvani Curti; Companhoni, Mychelle Vianna; Nakamura, Tânia Ueda

    2016-01-01

    Highlights: • Films and fibers of PMMA/ZnO nanocomposite were prepared. • ZnO NPs incorporated into PMMA fibers reduces their diameter and beads presence. • PMMA films containing ZnO exhibit higher thermal stability than pure polymer. • PMMA/ZnO nanocomposites show improved optical properties compared to pure polymer. • PMMA/ZnO shows potential for applications in tissue engineering. - Abstract: Films and fibers of PMMA/ZnO nanocomposites (100/0, 99/01, 97/03, 95/05, 90/10, and 85/15 wt.%) were produced by casting and electrospinning, respectively. Their structural, thermal, and optical properties were investigated by XRD, SEM, TGA, PAS, and PL. The incorporation of ZnO NPs reduced the diameter of PMMA fibers and the presence of beads. The surfaces of the fibers exhibited greater hydrophobicity, compared to the films, with contact angles of around 120° and 94°, respectively. PMMA films containing ZnO exhibited higher thermal stability than the pure polymer, while the corresponding fibers did not show any changes in thermal stability. The dispersion of the ZnO NPs at the surface and in the bulk of the nanocomposites appeared to be relatively homogeneous. ZnO improved the optical properties of the PMMA, with an intense absorption band near 370 nm observed for all the nanocomposites, which also exhibited luminescence with emission in the near-UV region, both attributed to ZnO. Biological tests demonstrated that fibers and films with up to 1% of ZnO exhibited good performance in the proliferation of fibroblast cells, indicating their potential for applications in tissue engineering. The fibers provided higher cell viability than the films, presumably due to their greater surface area and/or more suitable surface morphology. Nanocomposites with 15% ZnO inhibited cell proliferation, due to the cytotoxicity of the ZnO NPs. Although several applications of PMMA have been suggested by biomedical researchers, until now there have been no reports on the specific

  12. Structural, thermal, optical properties and cytotoxicity of PMMA/ZnO fibers and films: Potential application in tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Balen, Rodrigo; Vidotto da Costa, Wilian; Lara Andrade, Jéssica de; Piai, Juliana Francis [Programa de Pós-Graduação em Química, Departamento de Química, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Zona Sete, Maringá, PR (Brazil); Muniz, Edvani Curti [Programa de Pós-Graduação em Química, Departamento de Química, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Zona Sete, Maringá, PR (Brazil); Programa de Pós-Graduação em Biotecnologia Aplicada à Agricultura, Universidade Paranaense (UNIPAR), 87502-210, Umuarama, PR (Brazil); Programa de Pós- Graduação em Ciências de Materiais & Engenharia, Universidade Tecnológica Federal do Paraná (UTFPR-LD), 86036-370, Londrina, PR (Brazil); Companhoni, Mychelle Vianna; Nakamura, Tânia Ueda [Departamento de Ciências Básicas da Saúde, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Zona Sete, Maringá, PR (Brazil); and others

    2016-11-01

    Highlights: • Films and fibers of PMMA/ZnO nanocomposite were prepared. • ZnO NPs incorporated into PMMA fibers reduces their diameter and beads presence. • PMMA films containing ZnO exhibit higher thermal stability than pure polymer. • PMMA/ZnO nanocomposites show improved optical properties compared to pure polymer. • PMMA/ZnO shows potential for applications in tissue engineering. - Abstract: Films and fibers of PMMA/ZnO nanocomposites (100/0, 99/01, 97/03, 95/05, 90/10, and 85/15 wt.%) were produced by casting and electrospinning, respectively. Their structural, thermal, and optical properties were investigated by XRD, SEM, TGA, PAS, and PL. The incorporation of ZnO NPs reduced the diameter of PMMA fibers and the presence of beads. The surfaces of the fibers exhibited greater hydrophobicity, compared to the films, with contact angles of around 120° and 94°, respectively. PMMA films containing ZnO exhibited higher thermal stability than the pure polymer, while the corresponding fibers did not show any changes in thermal stability. The dispersion of the ZnO NPs at the surface and in the bulk of the nanocomposites appeared to be relatively homogeneous. ZnO improved the optical properties of the PMMA, with an intense absorption band near 370 nm observed for all the nanocomposites, which also exhibited luminescence with emission in the near-UV region, both attributed to ZnO. Biological tests demonstrated that fibers and films with up to 1% of ZnO exhibited good performance in the proliferation of fibroblast cells, indicating their potential for applications in tissue engineering. The fibers provided higher cell viability than the films, presumably due to their greater surface area and/or more suitable surface morphology. Nanocomposites with 15% ZnO inhibited cell proliferation, due to the cytotoxicity of the ZnO NPs. Although several applications of PMMA have been suggested by biomedical researchers, until now there have been no reports on the specific

  13. The successful demonstration of aerobic landfilling. The potential for a more sustainable solid waste management approach?

    Energy Technology Data Exchange (ETDEWEB)

    Read, A.D. [School of Earth Science and Geography, Center for Environmental and Earth Science Research, Kingston University, Penrhyn Road, Surrey, KT1 2EE Kingston upon Thames (United Kingdom); Hudgins, M. [Environmental Control Systems Inc., Atlanta, GA (United States); Harper, S. [US Environmental Protection Agency, Region IV, Atlanta, GA (United States); Phillips, P. [School of Environmental Science, University College Northampton, Northampton (United Kingdom); Morris, J. [School of Law and Accountancy, University College Northampton, Northampton (United Kingdom)

    2001-06-01

    Municipal solid waste (MSW) landfills worldwide are experiencing the consequences of conventional landfilling techniques, whereby anaerobic conditions are created within the landfilled waste. Under anaerobic conditions within a landfill site slow stabilization of the waste mass occurs, producing methane, (an explosive 'green house' gas) and leachate (which can pollute groundwater) over long periods of time. As a potential solution, it was demonstrated that the aerobic degradation of MSW within a landfill can significantly increase the rate of waste decomposition and settlement, decrease the methane production and leachate leaving the system, and potentially increase the operational life of the site. Readily integrated into the existing landfill infrastructure, this approach can safely and cost-effectively convert a MSW landfill from anaerobic to aerobic degradation processes, thereby effectively composting much of the organic portions (one of the potentially polluting elements in a conventional landfill site) of the waste. This paper summarizes the successful results of two separate aerobic landfill projects located in Georgia (USA) and discusses the potential, economic and environmental impacts to worldwide solid waste management practices.

  14. Momentum dependence of the imaginary part of the ω- and η{sup '}-nucleus optical potential

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, S.; Nanova, M.; Metag, V.; Brinkmann, K.T.; Drexler, P.; Gutz, E.; Makonyi, K.; Zaunick, H.G. [Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Afzal, F.N.; Beck, R.; Becker, M.; Boese, S.; Funke, C.; Gottschall, M.; Gruener, M.; Hammann, C.; Hartmann, J.; Hoffmeister, P.; Honisch, C.; Kaiser, D.; Kalischewski, F.; Koop, K.; Lang, M.; Mueller, J.; Muellers, J.; Piontek, D.M.; Schaab, D.; Schmidt, C.; Schmitz, R.; Seifen, T.; Sokhoyan, V.; Spieker, K.; Thiel, A.; Thoma, U.; Urban, M.; Pee, H. van; Walther, D.; Wendel, C.; Wilson, A.; Wunderlich, Y. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Bayadilov, D. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Bantes, B.; Eberhardt, H.; Elsner, D.; Frommberger, F.; Hannappel, J.; Hillert, W.; Jude, T.; Klein, F.; Messi, F.; Schmieden, H. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany); Crede, V. [Florida State University, Department of Physics, Tallahassee, FL (United States); Keshelashvili, I.; Krusche, B.; Rostomyan, T.; Werthmueller, D.; Witthauer, L. [Universitaet Basel, Departement Physik, Basel (Switzerland); Sowa, C.; Triffterer, T.; Wiedner, U. [Universitaet Bochum, Physikalisches Institut, Bochum (Germany); Collaboration: The CBELSA/TAPS Collaboration

    2016-09-15

    The photoproduction of ω and η{sup '} mesons off carbon and niobium nuclei has been measured as a function of the meson momentum for incident photon energies of 1.2-2.9 GeV at the electron accelerator ELSA. The mesons have been identified via the ω → π{sup 0}γ → 3γ and η{sup '} → π{sup 0}π{sup 0}η → 6γ decays, respectively, registered with the CBELSA/TAPS detector system. From the measured meson momentum distributions the momentum dependence of the transparency ratio has been determined for both mesons. Within a Glauber analysis the in-medium ω and η{sup '} widths and the corresponding absorption cross sections have been deduced as a function of the meson momentum. The results are compared to recent theoretical predictions for the in-medium ω width and η{sup '}-N absorption cross sections. The energy dependence of the imaginary part of the ω- and η{sup '}-nucleus optical potential has been extracted. The finer binning of the present data compared to the existing data allows a more reliable extrapolation towards the production threshold. The modulus of the imaginary part of the η{sup '}-nucleus potential is found to be about three times smaller than recently determined values of the real part of the η{sup '}-nucleus potential, which makes the η{sup '} meson a suitable candidate for the search for meson-nucleus bound states. For the ω meson, the modulus of the imaginary part near threshold is comparable to the modulus of the real part of the potential. As a consequence, only broad structures can be expected, which makes the observation of ω mesic states very difficult experimentally. (orig.)

  15. Pharmacological modulations of cardiac ultra-rapid and slowly activating delayed rectifier currents: potential antiarrhythmic approaches.

    Science.gov (United States)

    Islam, Mohammed A

    2010-01-01

    Despite the emerging new insights into our understandings of the cellular mechanisms underlying cardiac arrhythmia, medical therapy for this disease remains unsatisfactory. Atrial fibrillation (AF), the most prevalent arrhythmia, is responsible for significant morbidity and mortality. On the other hand, ventricular fibrillation results in sudden cardiac deaths in many instances. Prolongation of cardiac action potential (AP) is a proven principle of antiarrhythmic therapy. Class III antiarrhythmic agents prolong AP and QT interval by blocking rapidly activating delayed rectifier current (I(Kr)). However, I(Kr) blocking drugs carry the risk of life-threatening proarrhythmia. Recently, modulation of atrial-selective ultra-rapid delayed rectifier current (I(Kur)), has emerged as a novel therapeutic approach to treat AF. A number of I(Kur) blockers are being evaluated for the treatment of AF. The inhibition of slowly activating delayed rectifier current (I(Ks)) has also been proposed as an effective and safer antiarrhythmic approach because of its distinguishing characteristics that differ in remarkable ways from other selective class III agents. Selective I(Ks) block may prolong AP duration (APD) at rapid rates without leading to proarrhythmia. This article reviews the pathophysiological roles of I(Kur) and I(Ks) in cardiac repolarization and the implications of newly developed I(Kur) and I(Ks) blocking agents as promising antiarrhythmic approaches. Several recent patents pertinent to antiarrhythmic drug development have been discussed. Further research will be required to evaluate the efficacy and safety of these agents in the clinical setting.

  16. Racioethnicity, community makeup, and potential employees' reactions to organizational diversity management approaches.

    Science.gov (United States)

    Olsen, Jesse E; Martins, Luis L

    2016-05-01

    We draw on the values literature from social psychology and the acculturation literature from cross-cultural psychology to develop and test a theory of how signals about an organization's diversity management (DM) approach affect perceptions of organizational attractiveness among potential employees. We examine the mediating effects of individuals' merit-based attributions about hiring decisions at the organization, as well as the moderating effects of their racioethnicity and the racioethnic composition of their home communities. We test our theory using a within-subject policy-capturing experimental design that simulates organizational DM approaches, supplemented with census data for the participants' home communities. Results of hierarchical linear modeling (HLM) analyses suggest that the manipulated instrumental value for diversity leads to higher perceptions of organizational attractiveness, in part through heightened expectations of merit-based hiring decisions. Further, the manipulated assimilative and integrative DM approach signals are positively related to organizational attractiveness and the effect of integrative DM is strongest for racioethnic minorities from communities with especially high proportions of Whites and Whites from communities with especially low proportions of Whites. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  17. Worldwide Alien Invasion: A Methodological Approach to Forecast the Potential Spread of a Highly Invasive Pollinator.

    Directory of Open Access Journals (Sweden)

    André L Acosta

    Full Text Available The ecological impacts of alien species invasion are a major threat to global biodiversity. The increasing number of invasion events by alien species and the high cost and difficulty of eradicating invasive species once established require the development of new methods and tools for predicting the most susceptible areas to invasion. Invasive pollinators pose serious threats to biodiversity and human activity due to their close relationship with many plants (including crop species and high potential competitiveness for resources with native pollinators. Although at an early stage of expansion, the bumblebee species Bombus terrestris is becoming a representative case of pollinator invasion at a global scale, particularly given its high velocity of invasive spread and the increasing number of reports of its impacts on native bees and crops in many countries. We present here a methodological framework of habitat suitability modeling that integrates new approaches for detecting habitats that are susceptible to Bombus terrestris invasion at a global scale. Our approach did not include reported invaded locations in the modeling procedure; instead, those locations were used exclusively to evaluate the accuracy of the models in predicting suitability over regions already invaded. Moreover, a new and more intuitive approach was developed to select the models and evaluate different algorithms based on their performance and predictive convergence. Finally, we present a comprehensive global map of susceptibility to Bombus terrestris invasion that highlights priority areas for monitoring.

  18. An Ensemble Approach for Improved Short-to-Intermediate-Term Seismic Potential Evaluation

    Science.gov (United States)

    Yu, Huaizhong; Zhu, Qingyong; Zhou, Faren; Tian, Lei; Zhang, Yongxian

    2017-06-01

    Pattern informatics (PI), load/unload response ratio (LURR), state vector (SV), and accelerating moment release (AMR) are four previously unrelated subjects, which are sensitive, in varying ways, to the earthquake's source. Previous studies have indicated that the spatial extent of the stress perturbation caused by an earthquake scales with the moment of the event, allowing us to combine these methods for seismic hazard evaluation. The long-range earthquake forecasting method PI is applied to search for the seismic hotspots and identify the areas where large earthquake could be expected. And the LURR and SV methods are adopted to assess short-to-intermediate-term seismic potential in each of the critical regions derived from the PI hotspots, while the AMR method is used to provide us with asymptotic estimates of time and magnitude of the potential earthquakes. This new approach, by combining the LURR, SV and AMR methods with the choice of identified area of PI hotspots, is devised to augment current techniques for seismic hazard estimation. Using the approach, we tested the strong earthquakes occurred in Yunnan-Sichuan region, China between January 1, 2013 and December 31, 2014. We found that most of the large earthquakes, especially the earthquakes with magnitude greater than 6.0 occurred in the seismic hazard regions predicted. Similar results have been obtained in the prediction of annual earthquake tendency in Chinese mainland in 2014 and 2015. The studies evidenced that the ensemble approach could be a useful tool to detect short-to-intermediate-term precursory information of future large earthquakes.

  19. Biomechanical approaches to understanding the potentially injurious demands of gymnastic-style impact landings

    Directory of Open Access Journals (Sweden)

    Gittoes Marianne JR

    2012-01-01

    Full Text Available Abstract Gymnasts are exposed to a high incidence of impact landings due to the execution of repeated dismount performances. Biomechanical research can help inform recent discussions surrounding a proposed rule change in potentially injurious gymnastic dismounting. The review examines existing understanding of the mechanisms influencing the impact loads incurred in gymnastic-style landings achieved using biomechanical approaches. Laboratory-based and theoretical modelling research of inherent and regulatory mechanisms is appraised. The integration of the existing insights into injury prevention interventions studies is further considered in the appraisals. While laboratory-based studies have traditionally been favoured, the difficulty in controlling and isolating mechanisms of interest has partially restricted the understanding gained. An increase in the use of theoretical approaches has been evident over the past two decades, which has successfully enhanced insight into less readily modified mechanisms. For example, the important contribution of mass compositions and 'tuned' mass coupling responses to impact loading has been evidenced. While theoretical studies have advanced knowledge in impact landing mechanics, restrictions in the availability of laboratory-based input data have suppressed the benefits gained. The advantages of integrating laboratory-based and theoretical approaches in furthering scientific understanding of loading mechanisms have been recognised in the literature. Since a multi-mechanism contribution to impact loading has been evident, a deviation away from studies examining isolated mechanisms may be supported for the future. A further scientific understanding of the use of regulatory mechanisms in alleviating a performer's inherent injury predisposition may subsequently be gained and used to inform potential rule changes in gymnastics. While the use of controlled studies for providing scientific evidence for the

  20. Analytical approach for modeling and performance analysis of microring resonators as optical filters with multiple output bus waveguides

    Science.gov (United States)

    Lakra, Suchita; Mandal, Sanjoy

    2017-06-01

    A quadruple micro-optical ring resonator (QMORR) with multiple output bus waveguides is mathematically modeled and analyzed by making use of the delay-line signal processing approach in Z-domain and Mason's gain formula. The performances of QMORR with two output bus waveguides with vertical coupling are analyzed. This proposed structure is capable of providing wider free spectral response from both the output buses with appreciable cross talk. Thus, this configuration could provide increased capacity to insert a large number of communication channels. The simulated frequency response characteristic and its dispersion and group delay characteristics are graphically presented using the MATLAB environment.