WorldWideScience

Sample records for lens acs slacs

  1. The Sloan Lens ACS Survey. I. A large spectroscopically selected sample of massive early-type lens galaxies

    NARCIS (Netherlands)

    Bolton, AS; Burles, S; Koopmans, LVE; Treu, T; Moustakas, LA

    2006-01-01

    The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope (HST) Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected spectroscopically from the Sloan Digital Sky Survey (SDSS) database of galaxy spectra for having multiple

  2. The Sloan Lens ACS Survey. XIII. Discovery of 40 New Galaxy-scale Strong Lenses

    Science.gov (United States)

    Shu, Yiping; Brownstein, Joel R.; Bolton, Adam S.; Koopmans, Léon V. E.; Treu, Tommaso; Montero-Dorta, Antonio D.; Auger, Matthew W.; Czoske, Oliver; Gavazzi, Raphaël; Marshall, Philip J.; Moustakas, Leonidas A.

    2017-12-01

    We present the full sample of 118 galaxy-scale strong-lens candidates in the Sloan Lens ACS (SLACS) Survey for the Masses (S4TM) Survey, which are spectroscopically selected from the final data release of the Sloan Digital Sky Survey. Follow-up Hubble Space Telescope (HST) imaging observations confirm that 40 candidates are definite strong lenses with multiple lensed images. The foreground-lens galaxies are found to be early-type galaxies (ETGs) at redshifts 0.06–0.44, and background sources are emission-line galaxies at redshifts 0.22–1.29. As an extension of the SLACS Survey, the S4TM Survey is the first attempt to preferentially search for strong-lens systems with relatively lower lens masses than those in the pre-existing strong-lens samples. By fitting HST data with a singular isothermal ellipsoid model, we find that the total projected mass within the Einstein radius of the S4TM strong-lens sample ranges from 3 × 1010 M ⊙ to 2 × 1011 M ⊙. In Shu et al., we have derived the total stellar mass of the S4TM lenses to be 5 × 1010 M ⊙ to 1 × 1012 M ⊙. Both the total enclosed mass and stellar mass of the S4TM lenses are on average almost a factor of 2 smaller than those of the SLACS lenses, which also represent the typical mass scales of the current strong-lens samples. The extended mass coverage provided by the S4TM sample can enable a direct test, with the aid of strong lensing, for transitions in scaling relations, kinematic properties, mass structure, and dark-matter content trends of ETGs at intermediate-mass scales as noted in previous studies. Based on observations made with the NASA/ESA Hubble Space Telescope (HST), obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. These observations are associated with HST program #12210.

  3. The sloan lens acs survey. II. Stellar populations and internal structure of early-type lens galaxies

    NARCIS (Netherlands)

    Treu, Tommaso; Koopmans, Léon V.; Bolton, Adam S.; Burles, Scott; Moustakas, Leonidas A.

    2006-01-01

    We use HST images to derive effective radii and effective surface brightnesses of 15 early-type (E+S0) lens galaxies identified by the SLACS Survey. Our measurements are combined with stellar velocity dispersions from the SDSS database to investigate for the first time the distribution of lens

  4. THE BOSS EMISSION-LINE LENS SURVEY. II. INVESTIGATING MASS-DENSITY PROFILE EVOLUTION IN THE SLACS+BELLS STRONG GRAVITATIONAL LENS SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, Adam S.; Brownstein, Joel R.; Shu Yiping; Arneson, Ryan A. [Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, UT 84112 (United States); Kochanek, Christopher S. [Department of Astronomy and Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Schlegel, David J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Eisenstein, Daniel J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Wake, David A. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Connolly, Natalia [Department of Physics, Hamilton College, Clinton, NY 13323 (United States); Maraston, Claudia [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Weaver, Benjamin A., E-mail: bolton@astro.utah.edu [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States)

    2012-09-20

    We present an analysis of the evolution of the central mass-density profile of massive elliptical galaxies from the SLACS and BELLS strong gravitational lens samples over the redshift interval z Almost-Equal-To 0.1-0.6, based on the combination of strong-lensing aperture mass and stellar velocity-dispersion constraints. We find a significant trend toward steeper mass profiles (parameterized by the power-law density model with {rho}{proportional_to}r {sup -{gamma}}) at later cosmic times, with magnitude d < {gamma} > /dz = -0.60 {+-} 0.15. We show that the combined lens-galaxy sample is consistent with a non-evolving distribution of stellar velocity dispersions. Considering possible additional dependence of <{gamma} > on lens-galaxy stellar mass, effective radius, and Sersic index, we find marginal evidence for shallower mass profiles at higher masses and larger sizes, but with a significance that is subdominant to the redshift dependence. Using the results of published Monte Carlo simulations of spectroscopic lens surveys, we verify that our mass-profile evolution result cannot be explained by lensing selection biases as a function of redshift. Interpreted as a true evolutionary signal, our result suggests that major dry mergers involving off-axis trajectories play a significant role in the evolution of the average mass-density structure of massive early-type galaxies over the past 6 Gyr. We also consider an alternative non-evolutionary hypothesis based on variations in the strong-lensing measurement aperture with redshift, which would imply the detection of an 'inflection zone' marking the transition between the baryon-dominated and dark-matter halo-dominated regions of the lens galaxies. Further observations of the combined SLACS+BELLS sample can constrain this picture more precisely, and enable a more detailed investigation of the multivariate dependences of galaxy mass structure across cosmic time.

  5. THE BOSS EMISSION-LINE LENS SURVEY (BELLS). I. A LARGE SPECTROSCOPICALLY SELECTED SAMPLE OF LENS GALAXIES AT REDSHIFT {approx}0.5

    Energy Technology Data Exchange (ETDEWEB)

    Brownstein, Joel R.; Bolton, Adam S.; Pandey, Parul [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Schlegel, David J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Eisenstein, Daniel J. [Harvard College Observatory, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Kochanek, Christopher S. [Department of Astronomy and Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Connolly, Natalia [Department of Physics, Hamilton College, Clinton, NY 13323 (United States); Maraston, Claudia [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Seitz, Stella [University Observatory Munich, Scheinstrasse 1, 81679 Muenchen (Germany); Wake, David A. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Wood-Vasey, W. Michael [Pittsburgh Center for Particle Physics, Astrophysics, and Cosmology (PITT-PACC), Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Brinkmann, Jon [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics and Institute for Gravitation and the Cosmos, Pennsylvania State University, University Park, PA 16802 (United States); Weaver, Benjamin A. [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States)

    2012-01-01

    We present a catalog of 25 definite and 11 probable strong galaxy-galaxy gravitational lens systems with lens redshifts 0.4 {approx}< z {approx}< 0.7, discovered spectroscopically by the presence of higher-redshift emission lines within the Baryon Oscillation Spectroscopic Survey (BOSS) of luminous galaxies, and confirmed with high-resolution Hubble Space Telescope (HST) images of 44 candidates. Our survey extends the methodology of the Sloan Lens Advanced Camera for Surveys survey (SLACS) to higher redshift. We describe the details of the BOSS spectroscopic candidate detections, our HST ACS image processing and analysis methods, and our strong gravitational lens modeling procedure. We report BOSS spectroscopic parameters and ACS photometric parameters for all candidates, and mass-distribution parameters for the best-fit singular isothermal ellipsoid models of definite lenses. Our sample to date was selected using only the first six months of BOSS survey-quality spectroscopic data. The full five-year BOSS database should produce a sample of several hundred strong galaxy-galaxy lenses and in combination with SLACS lenses at lower redshift, strongly constrain the redshift evolution of the structure of elliptical, bulge-dominated galaxies as a function of luminosity, stellar mass, and rest-frame color, thereby providing a powerful test for competing theories of galaxy formation and evolution.

  6. Plasma lenses for SLAC Final Focus Test facility

    International Nuclear Information System (INIS)

    Betz, D.; Cline, D.; Joshi, C.; Rajagopalan, S.; Rosenzweig, J.; Su, J.J.; Williams, R.; Chen, P.; Gundersen, M.; Katsouleas, T.; Norem, J.

    1991-01-01

    A collaborative group of accelerator and plasma physicists and engineers has formed with an interest in exploring the use of plasma lenses to meet the needs of future colliders. Analytic and computational models of plasma lenses are briefly reviewed and several design examples for the SLAC Final Focus Test Beam are presented. The examples include discrete, thick, and adiabatic lenses. A potential plasma source with desirable lens characteristics is presented

  7. Combined pars plana lensectomy-vitrectomy with open-loop flexible anterior chamber intraocular lens (AC IOL) implantation for subluxated lenses.

    Science.gov (United States)

    Kazemi, S; Wirostko, W J; Sinha, S; Mieler, W F; Koenig, S B; Sheth, B P

    2000-01-01

    To review our experience with combined pars plana lensectomy-vitrectomy and open-loop flexible anterior chamber intraocular lens (AC IOL) implantation for managing subluxated crystalline lenses. Retrospective review of 36 consecutive eyes (28 patients), all of which had subluxated crystalline lenses, managed by pars plana lensectomy-vitrectomy with insertion of an open-loop flexible AC IOL. The study was performed at the Medical College of Wisconsin, Milwaukee, over an 8-year period. An average preoperative visual acuity of 20/163 (range, 20/25 to hand motions) improved to 20/36 (range, 20/20 to 4/200) with surgery after a mean follow-up of 14 months (range, 1 to 59 months) (P IOL implantation appears to be an excellent technique for managing subluxated crystalline lenses. It is associated with a significant improvement in visual acuity (P subluxated lens through a limbal wound. Additionally, use of an AC IOL offers a simplified alternative to placement of a ciliary sulcus sutured posterior chamber intraocular lens (PC IOL).

  8. SLAC site design aesthetics

    International Nuclear Information System (INIS)

    Hall, F.F.

    1985-10-01

    Stanford Linear Accelerator Center (SLAC) is a single mission laboratory dedicated to basic research in high energy particle physics. SLAC site also houses Stanford Synchrotron Radiation Laboratory (SSRL) which is a multi-mission laboratory for research using beams of ultraviolet light and low energy photons as emitted tangentially from SLAC colliding beam facilities. This paper discusses various aspects of SLAC site design aesthetics under the following headings: (1) imposed footprint of SLAC, (2) description of selected site, (3) use of earth cover for radiation and sight screens, (4) use of landscaping for cosmetic purposes, (5) use of exterior paint colors to soften SLAC impact on neighbors, (6) relocation of SLAC main entrance, (7) relocation of SLAC collider arcs and experimental hall, (8) parking lots and storage yards, and (9) land use zoning at SLAC

  9. Golden gravitational lensing systems from the Sloan Lens ACS Survey - II. SDSS J1430+4105: a precise inner total mass profile from lensing alone

    Science.gov (United States)

    Eichner, Thomas; Seitz, Stella; Bauer, Anne

    2012-12-01

    We study the Sloan Lens ACS (SLACS) survey strong-lensing system SDSS J1430+4105 at zl = 0.285. The lensed source (zs = 0.575) of this system has a complex morphology with several subcomponents. Its subcomponents span a radial range from 4 to 10 kpc in the plane of the lens. Therefore, we can constrain the slope of the total projected mass profile around the Einstein radius from lensing alone. We measure a density profile that is slightly but not significantly shallower than isothermal at the Einstein radius. We decompose the mass of the lensing galaxy into a de Vaucouleurs component to trace the stars and an additional dark component. The spread of multiple-image components over a large radial range also allows us to determine the amplitude of the de Vaucouleurs and dark matter components separately. We get a mass-to-light ratio of M de Vauc LB ≈ (5.5±1.5) M⊙L⊙,B and a dark matter fraction within the Einstein radius of ≈20 to 40 per cent. Modelling the star formation history assuming composite stellar populations at solar metallicity to the galaxy's photometry yields a mass-to-light ratio of M, salp LB ≈ 4.0-1.3+0.6 M⊙L⊙,B and M, chab LB ≈ 2.3-0.8+0.3 M⊙L⊙,B for Salpeter and Chabrier initial mass functions, respectively. Hence, the mass-to-light ratio derived from lensing is more Salpeter like, in agreement with results for massive Coma galaxies and other nearby massive early-type galaxies. We examine the consequences of the galaxy group in which the lensing galaxy is embedded, showing that it has little influence on the mass-to-light ratio obtained for the de Vaucouleurs component of the lensing galaxy. Finally, we decompose the projected, azimuthally averaged 2D density distribution of the de Vaucouleurs and dark matter components of the lensing signal into spherically averaged 3D density profiles. We can show that the 3D dark and luminous matter density within the Einstein radius (REin ≈ 0.6 Reff) of this SLACS galaxy is similar to the

  10. THE SLACS SURVEY. VIII. THE RELATION BETWEEN ENVIRONMENT AND INTERNAL STRUCTURE OF EARLY-TYPE GALAXIES

    NARCIS (Netherlands)

    Treu, Tommaso; Gavazzi, Raphael; Gorecki, Alexia; Marshall, Philip J.; Koopmans, Leon V. E.; Bolton, Adam S.; Moustakas, Leonidas A.; Burles, Scott

    2009-01-01

    We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the SLACS Survey. The Sloan Digital Sky Survey (SDSS) database is used to determine two measures of overdensity of galaxies around each lens-the projected

  11. Recent Upgrade of the Klystron Modulator at SLAC

    International Nuclear Information System (INIS)

    Nguyen, M.N.; Burkhart, C.P.; Lam, B.K.; Morris, B.

    2011-01-01

    The SLAC National Accelerator Laboratory employs 244 klystron modulators on its two-mile-long linear accelerator that has been operational since the early days of the SLAC establishment in the sixties. Each of these original modulators was designed to provide 250 kV, 262 A and 3.5 μS at up to 360 pps using an inductance-capacitance resonant charging system, a modified type-E pulse-forming network (PFN), and a pulse transformer. The modulator internal control comprised of large step-start resistor-contactors, vacuum-tube amplifiers, and 120 Vac relays for logical signals. A major, power-component-only upgrade, which began in 1983 to accommodate the required beam energy of the SLAC Linear Collider (SLC) project, raised the modulator peak output capacity to 360 kV, 420 A and 5.0 μS at a reduced pulse repetition rate of 120 pps. In an effort to improve safety, performance, reliability and maintainability of the modulator, this recent upgrade focuses on the remaining three-phase AC power input and modulator controls. The upgrade includes the utilization of primary SCR phase control rectifiers, integrated fault protection and voltage regulation circuitries, and programmable logic controllers (PLC) -- with an emphasis on component physical layouts for safety and maintainability concerns. In this paper, we will describe the design and implementation of each upgraded component in the modulator control system. We will also report the testing and present status of the modified modulators.

  12. The stellar initial mass function of early-type galaxies from low to high stellar velocity dispersion: homogeneous analysis of ATLAS3D and Sloan Lens ACS galaxies

    Science.gov (United States)

    Posacki, Silvia; Cappellari, Michele; Treu, Tommaso; Pellegrini, Silvia; Ciotti, Luca

    2015-01-01

    We present an investigation about the shape of the initial mass function (IMF) of early-type galaxies (ETGs), based on a joint lensing and dynamical analysis, and on stellar population synthesis models, for a sample of 55 lens ETGs identified by the Sloan Lens Advanced Camera for Surveys (SLACS). We construct axisymmetric dynamical models based on the Jeans equations which allow for orbital anisotropy and include a dark matter halo. The models reproduce in detail the observed Hubble Space Telescope photometry and are constrained by the total projected mass within the Einstein radius and the stellar velocity dispersion (σ) within the Sloan Digital Sky Survey fibres. Comparing the dynamically-derived stellar mass-to-light ratios (M*/L)dyn, obtained for an assumed halo slope ρh ∝ r-1, to the stellar population ones (M*/L)Salp, derived from full-spectrum fitting and assuming a Salpeter IMF, we infer the mass normalization of the IMF. Our results confirm the previous analysis by the SLACS team that the mass normalization of the IMF of high-σ galaxies is consistent on average with a Salpeter slope. Our study allows for a fully consistent study of the trend between IMF and σ for both the SLACS and atlas3D samples, which explore quite different σ ranges. The two samples are highly complementary, the first being essentially σ selected, and the latter volume-limited and nearly mass selected. We find that the two samples merge smoothly into a single trend of the form log α = (0.38 ± 0.04) × log (σe/200 km s-1) + ( - 0.06 ± 0.01), where α = (M*/L)dyn/(M*/L)Salp and σe is the luminosity averaged σ within one effective radius Re. This is consistent with a systematic variation of the IMF normalization from Kroupa to Salpeter in the interval σe ≈ 90-270 km s-1.

  13. SLAC linear collider

    International Nuclear Information System (INIS)

    Richter, B.; Bell, R.A.; Brown, K.L.

    1980-06-01

    The SLAC LINEAR COLLIDER is designed to achieve an energy of 100 GeV in the electron-positron center-of-mass system by accelerating intense bunches of particles in the SLAC linac and transporting the electron and positron bunches in a special magnet system to a point where they are focused to a radius of about 2 microns and made to collide head on. The rationale for this new type of colliding beam system is discussed, the project is described, some of the novel accelerator physics issues involved are discussed, and some of the critical technical components are described

  14. Environment, Safety & Health at SLAC

    Science.gov (United States)

    and safety of our staff, the community, and the environment as we carry out our scientific mission. We integral to each job. As stewards of our land, SLAC also seeks to minimize pollution to our environment and to protect our resources and biota. See the SLAC Environment, Safety and Health Policy for more

  15. PEP-II Large Power Supplies Rebuild Program at SLAC

    CERN Document Server

    de Lira, Antonio C; Lipari, James J; da Silva Rafael, Fernando

    2005-01-01

    At PEP-II, seven large power supplies (LGPS) are used to power quad magnets in the electron-positron collider region. The LGPS ratings range from 72kW to 270kW, and were installed in 1997. They are unipolar off-line switch mode supplies, with a 6 pulse bridge rectifying 480VAC, 3-phase input power to yield 650VDC unregulated. This unregulated 650VDC is then input into one (or two) IGBT H-bridges, which convert the DC into PWM 16 kHz square wave AC. This high frequency AC drives the primary side of a step-down transformer followed by rectifiers and low pass filters. Over the years, these LGPS have presented many problems mainly in their control circuits, making it difficult to troubleshoot and affecting the overall accelerator availability. A redesign/rebuilding program for these power supplies was established under the coordination of the Power Conversion Department at SLAC. During the 2004 accelerator summer shutdown all the control circuits in these supplies were redesigned and replaced. A new PWM control b...

  16. Search for exotic mesons at SLAC

    International Nuclear Information System (INIS)

    Bonamy, P.; Baggett, N.; Fieguth, T.

    1975-01-01

    The theoretical justification and results from recent experimental searches for backward-produced exotic mesons including two experiments carried out by the collaboration at SLAC are reviewed. The first experiment put upper limits of about 1 to 2 μb for X ++ → (2π, 4π, 6π) ++ and anti ppπ + π + in the reaction π + + p → X ++ + n/sub forward/ at 8.4 GeV/c studied with the SLAC 14 inch rapid cycling bubble chamber triggered by a downstream neutron detector. Also the important features of the recently completed second experiment with the SLAC streamer chamber to study the reaction π - + p → X -- + p/sub forward/ at 14 GeV/c are discussed

  17. No conflict between SLAC and Japan's KEK

    CERN Multimedia

    2000-01-01

    Letter from Helen Quinn from SLAC arguing that an article in Nature distorted her comments on the relationship between KEK and SLAC over their separate projects looking at CP violation. The author of the original article replies (1/2 page).

  18. SIMS: The SLAC Industrial Measurement System

    International Nuclear Information System (INIS)

    Bell, B.

    1990-01-01

    Kern was the first survey company to market an Industrial Measurement System when it released ECDS (Electronic Coordinate Determination System) in the mid-1980s. Originally written for the PDP-11, a version was later released for the PC (ECDS-PC). SLAC purchased this system in 1986 and immediately began to use it for the alignment of the SLC (Stanford Linear Collider). Although ECDS enabled SLAC to perform tasks with a speed never before achieved, they experienced limitations in the software. Since Kern proved unresponsive and SLAC was unable to purchase the source code for any amount of money, they set about writing their own portions of code. They first wrote a system of menus tailored for their specific alignment tasks, and disabled much of the ECDS menu structure. Due to dissatisfaction with the ECDS bundle adjustment program, they wrote their own bundle adjustment in 1988. A further step towarad having their own complete IMS was to develop a data capture program, a task which has been underway since the beginning of this year. They do not yet have data analysis features that are fully integrated, but they do have stand-alone packages that have been written at SLAC. When they first started tinkering with ECDS there was no intention of developing a complete system, but they now have all the elements of such a system - SIMS, the SLAC Industrial Measurement System

  19. An overview of the SLAC results

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1996-03-01

    The history of nucleon spin-structure measurements goes back to the early days of inelastic electron scattering at SLAC, when Vernon Hughes came with a proposal to accelerate polarized electrons to high energy and to study inelastic scattering from a polarized proton target. The quark model of the proton was new at the time, and the spin-dependent structure functions were an excellent testing ground for that model. The proposal developed into an experiment which became SLAC experiment E80. Subsequent experiments followed those early studies, leading to E130 at SLAC, then EMC at CERN, and a host of later experiments. In 1988 the EMC Collaboration published the first data to reach low x. The asymmetries EMC observed fell below quark model expectations, and the experimentally measured proton sum rule indicated that the spin of the quarks contributed little to the proton spin. The subject of nucleon spin-dependent structure functions was stimulated by this surprising result from EMC. The continuation of the spin-structure studies at SLAC, which have been very active in recent years, was stimulated by the successful development of high-intensity beams of polarized electrons. Table 1 lists the past, present, and planned programs and experiments that grew out of the early work. The rest of the report is divided into the following topics: polarized electrons; polarimetry; the SLAC spectrometers; radiative corrections; the proton measurements; neutron targets; the deuterium and 3 He data; the g 2 structure function; and the 50 GeV upgrade of the SLC

  20. New generation control system at SLAC

    International Nuclear Information System (INIS)

    Melen, R.

    1981-03-01

    The proposed SLAC Linear Collider (SLC) project will require an Instrumentation and Control system that provides integrated automatic monitoring and control functions. The present SLAC LINAC Instrumentation and Control system will be totally revamped and it will be expanded to include the support of all of the additional accelerator components that will be required for the whole SLC project. This paper describes the functional operation of the new system

  1. Annual Site Environmental Report: 2015 (ASER) for the SLAC National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sabba, Dellilah [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-09-01

    This report, prepared by the SLAC National Accelerator Laboratory (SLAC) for the U.S. Department of Energy (DOE), SLAC Site Office (SSO), provides a comprehensive summary of the environmental program activities at SLAC for calendar year 2015. Annual Site Environmental Reports (ASERs) are prepared for all DOE sites with significant environmental activities, and distributed to relevant external regulatory agencies and other interested organizations or individuals. To the best of my knowledge, this report accurately summarizes the results of the 2015 environmental monitoring, compliance, and restoration programs at SLAC. This assurance can be made based on SSO and SLAC review of the ASER, and quality assurance protocols applied to monitoring and data analyses at SLAC.

  2. SLAC three-body partial wave analysis system

    International Nuclear Information System (INIS)

    Aston, D.; Lasinski, T.A.; Sinervo, P.K.

    1985-10-01

    We present a heuristic description of the SLAC-LBL three-meson partial wave model, and describe how we have implemented it at SLAC. The discussion details the assumptions of the model and the analysis, and emphasizes the methods we have used to prepare and fit the data. 28 refs., 12 figs., 1 tab

  3. Low aperture magnetic elements measurements

    International Nuclear Information System (INIS)

    Aleksandrov, V.A.; Mikhajlichenko, A.A.; Parkhomchuk, V.V.; Seryj, A.A.; Shil'tsev, V.D.

    1991-01-01

    Two new methods of magnetic field measurements in low aperture elements are discussed. The first method uses thin magnetoresistive bismuth wire and the second-strained wire with AC. Principles of measuring used in the last technique are different from well known SLAC method of vibrating wire. Results of testing 0.38 T/mm quadrupole and VLEPP final focus test 3 T/mm lens are presented. Brief comparing of the lens axis determination precision of these methods is also discussed. 4 refs.; 8 figs

  4. SLC energy upgrade program at SLAC

    International Nuclear Information System (INIS)

    Loew, G.A.; Allen, M.A.; Cassel, R.L.; Dean, N.R.; Konrad, G.T.; Koontz, R.F.; Lebacqz, J.V.

    1985-01-01

    The SLAC Linear Collider (SLC) must reach a nominal center-of-mass energy of 100 GeV to fulfill its high energy physics goals. This paper describes the energy upgrade program that is being implemented on the SLAC linear accelerator to meet these goals. It includes a discussion of the design requirements and available technical options, the rationale for the adopted solution, and the technical problems involved in the engineering and production of klystrons and modulators

  5. SLC Energy Upgrade Program at SLAC

    International Nuclear Information System (INIS)

    Loew, G.A.; Allen, M.A.; Cassel, R.L.; Dean, N.R.; Konrad, G.T.; Koontz, R.F.; Lebacqz, J.V.

    1985-03-01

    The SLAC Linear Collider (SLC) must reach a nominal center-of-mass energy of 100 GeV to fulfill its high energy physics goals. This paper describes the energy upgrade program that is being implemented on the SLAC linear accelerator to meet these goals. It includes a discussion of the design requirements and available technical options, the rationale for the adopted solution, and the technical problems involved in the engineering and production of klystrons and modulators

  6. Status report on the alignment activities at SLAC

    International Nuclear Information System (INIS)

    Le Cocq, Catherine; Fuss, Brian; Ruland, Robert

    2003-01-01

    This report mainly focuses on the Alignment Engineering Group, which deals with all aspects of activities involving surveying and alignment at SLAC (Stanford Linear Accelerator Center). These activities are field work, ongoing studies and mapping effort. The majority of fieldwork at SLAC is initiated by the various current physics experiments. As PEP-II switched into operational mode, another major project was fully ramping up: SPEAR. The Stanford Synchrotron Radiation Laboratory (SSRL) had been preparing the upgrade SPEAR3 (3 GeV, 200 mA). Currently the effort has been to remap the entire SPEAR2 ring including existing magnets but also to map and tie in the connected booster ring. Laser trackers, total stations, and digital levels were used and substantial post processing was necessary to tie everything together. In parallel with field works, several instrumentation studies are in progress on laser tracker and total station, leveling instrumentation and gyro theodolites. Further enhancements have been included in the core network analysis package used at SLAC (LEGO). To keep up with the new installation, SLAC is undergoing an update of its site map. Overall this is a very interesting and dynamic time at SLAC, which celebrated its 40th anniversary on October 2nd 2002. (Y. Tanaka)

  7. GLOBAL OPTIMIZATION METHODS FOR GRAVITATIONAL LENS SYSTEMS WITH REGULARIZED SOURCES

    International Nuclear Information System (INIS)

    Rogers, Adam; Fiege, Jason D.

    2012-01-01

    Several approaches exist to model gravitational lens systems. In this study, we apply global optimization methods to find the optimal set of lens parameters using a genetic algorithm. We treat the full optimization procedure as a two-step process: an analytical description of the source plane intensity distribution is used to find an initial approximation to the optimal lens parameters; the second stage of the optimization uses a pixelated source plane with the semilinear method to determine an optimal source. Regularization is handled by means of an iterative method and the generalized cross validation (GCV) and unbiased predictive risk estimator (UPRE) functions that are commonly used in standard image deconvolution problems. This approach simultaneously estimates the optimal regularization parameter and the number of degrees of freedom in the source. Using the GCV and UPRE functions, we are able to justify an estimation of the number of source degrees of freedom found in previous work. We test our approach by applying our code to a subset of the lens systems included in the SLACS survey.

  8. The X-Shooter Lens Survey - I. Dark matter domination and a Salpeter-type initial mass function in a massive early-type galaxy

    Science.gov (United States)

    Spiniello, C.; Koopmans, L. V. E.; Trager, S. C.; Czoske, O.; Treu, T.

    2011-11-01

    We present the first results from the X-Shooter Lens Survey: an analysis of the massive early-type galaxy SDSS J1148+1930 at redshift z= 0.444. We combine its extended kinematic profile - derived from spectra obtained with X-Shooter on the European Southern Observatory Very Large Telescope - with strong gravitational lensing and multicolour information derived from Sloan Digital Sky Survey (SDSS) images. Our main results are as follows. (i) The luminosity-weighted stellar velocity dispersion is (≲Reff) = 352 ± 10 ± 16 km s-1, extracted from a rectangular aperture of 1.8 × 1.6 arcsec2 centred on the galaxy, more accurate and considerably lower than a previously published value of ˜450 km s-1. (ii) A single-component (stellar plus dark) mass model of the lens galaxy yields a logarithmic total-density slope of γ'= 1.72+0.05- 0.06 (68 per cent confidence level, CL; ?) within a projected radius of ˜2.16 arcsec. (iii) The projected stellar mass fraction, derived solely from the lensing and dynamical data, is f*(Salp(90 per cent CL and in some cases violate the total lensing-derived mass limit. We conclude that this very massive early-type galaxy is dark-matter-dominated inside one effective radius, consistent with the trend recently found from massive Sloan Lens ACS (SLACS) galaxies, with a total density slope shallower than isothermal and an IMF normalization consistent with Salpeter.

  9. Polarized Light Sources for photocathode electron guns at SLAC

    International Nuclear Information System (INIS)

    Woods, M.; Frisch, J.; Witte, K.; Zolotorev, M.

    1992-12-01

    We describe current and future Polarized Light Sources at SLAC for use with photocathode electron guns to produce polarized electron beams. The SLAC experiments SLD and E142 are considered, and are used to define the required parameters for the Polarized Light Sources

  10. The creation of SLAC leading to 30 years of operation

    International Nuclear Information System (INIS)

    Panofsky, W.K.H.

    1996-01-01

    The different phases of operation of SLAC which provided the basis of its longevity are outlined. SLAC has been an unusually productive laboratory both in terms of genuinely new revelations and the accumulation of archival data. Current operation of SLAC is divided between fixed target experiments, whose energy has now been extended to 50 GeV, and continued use of the SLC with the SLAC large detector. Because of the availability of polarization, results obtained in the SLC-SLD combination have been competitive with the experiments using LEP at CERN, notwithstanding the significantly larger available luminosities at the much larger LEP machine. In addition the SLC, together with specialized test facilities, constitute a basic laboratory to determine the design of the Next Linear Collider (NLC)

  11. The SLC energy upgrade program at SLAC

    International Nuclear Information System (INIS)

    Loew, G.A.; Allen, M.A.; Cassel, R.L.; Dean, N.R.; Konrad, G.T.; Koontz, R.F.; Lebaaqz, J.V.

    1985-01-01

    The SLAC Linear Collider (SLC) must reach a nominal center-of-mass energy of 100 GeV to fulfill its high energy physics goals. This paper describes the energy upgrade program that is being implemented on the SLAC linear accelerator to meet these goals. It includes a discussion of the design requirements and available technical options, the rationale for the adopted solution, and the technical problems involved in the engineering and production of klystrons and modulators

  12. Longitudinal and transverse wake potentials in SLAC

    International Nuclear Information System (INIS)

    Bane, K.; Wilson, P.

    1980-01-01

    In a machine with short bunches of high peak currents, such as the SLAC collider, one needs to know the longitudinal wake potential, for the higher mode losses, and the transverse wake potential, since, for bunches passing slightly off axis, the induced transverse forces will tend to cause beam break up. The longitudinal and transverse wakes of the SLAC structure presented here, were calculated by computer using the modal method, and including an analytic extension for higher modes. (Auth.)

  13. Computer control of rf at SLAC

    International Nuclear Information System (INIS)

    Schwarz, H.D.

    1985-03-01

    The Stanford Linear Accelerator is presently upgraded for the SLAC Linear Collider project. The energy is to be increased from approximately 31 GeV to 50 GeV. Two electron beams and one positron beam are to be accelerated with high demands on the quality of the beams. The beam specifications are shown. To meet these specifications, all parameters influencing the beams have to be under tight control and continuous surveillance. This task is accomplished by a new computer system implemented at SLAC which has, among many other functions, control over rf accelerating fields. 13 refs., 8 figs., 2 tabs

  14. The SLAC NLC source program

    International Nuclear Information System (INIS)

    Caryotakis, G.

    1995-01-01

    The SLAC approach to a future e + e - 1-TeV linear collider, which will probably be an internationally sponsored project at the turn of the century, is a conventional 14-kilometer accelerator operating at 11.4 GHz. SLAC is on the 6th year of a program to develop 50--100 MW klystron sources for the ''Next Linear Collider'' or ''NLC''. The paper traces the development of these tubes and presents experimental results for solenoid-focused klystrons with output circuits of both the standing-wave and traveling-wave variety. In addition, the design of a periodically-focused permanent magnet klystron is discussed and a tape is shown with time-sequenced simulations of the interaction process for such a tube

  15. SLAC synchronous condenser

    International Nuclear Information System (INIS)

    Corvin, C.

    1995-06-01

    A synchronous condenser is a synchronous machine that generates reactive power that leads real power by 90 degrees in phase. The leading reactive power generated by the condenser offsets or cancels the normal lagging reactive power consumed by inductive and nonlinear loads at the accelerator complex. The quality of SLAC's utility power is improved with the addition of the condenser. The inertia of the condenser's 35,000 pound rotor damps and smoothes voltage excursions on two 12 kilovolt master substation buses, improving voltage regulation site wide. The condenser absorbs high frequency transients and noise in effect ''scrubbing'' the electric system power at its primary distribution source. In addition, the condenser produces a substantial savings in power costs. Federal and investor owned utilities that supply electric power to SLAC levy a monthly penalty for lagging reactive power delivered to the site. For the 1993 fiscal year this totaled over $285,000 in added costs for the year. By generating leading reactive power on site, thereby reducing total lagging reactive power requirements, a substantial savings in electric utility bills is achieved. Actual savings of $150,000 or more a year are possible depending on experimental operations

  16. Operational experience with SLAC's beam containment electronics

    International Nuclear Information System (INIS)

    Constant, T.N.; Crook, K.; Heggie, D.

    1977-03-01

    Considerable operating experience was accumulated at SLAC with an extensive electronic system for the containment of high power accelerated beams. Average beam power at SLAC can approach 900 kilowatts with the potential for burning through beam stoppers, protection collimators, and other power absorbers within a few seconds. Fast, reliable, and redundant electronic monitoring circuits have been employed to provide some of the safeguards necessary for minimizing the risk to personnel. The electronic systems are described, and the design philosophy and operating experience are discussed

  17. SLAC workshop on high energy electroproduction and spin physics

    International Nuclear Information System (INIS)

    1992-01-01

    These Proceedings contain copies of the transparencies presented at the Workshop on High Energy Electroproduction and Spin Physics held at SLAC on February 5--8, 1992. The purpose of this Workshop was to bring people together to discuss the possibilities for new experiments using the SLAC high intensity electron and photon beams and the facilities of End Station A

  18. Transport of LCLS-II 1.3 Ghz cryomodule to SLAC

    Energy Technology Data Exchange (ETDEWEB)

    McGee, M. W.; Arkan, T.; Peterson, T.; Tang, Z.; Boo, S.; Carrasco, M.; Daly, E.; Huque, N.

    2016-06-30

    In a partnership with SLAC National Accelerator Laboratory (SLAC) and Jefferson Lab, Fermilab will assemble and test 17 of the 35 total 1.3 GHz cryomodules for the Linac Coherent Light Source II (LCLS-II) Project. These include a prototype built and delivered by each Lab. Another two 3.9 GHz cryomodules will be built, tested and transported by Fermilab to SLAC. Each assembly will be transported over-the-road from Fermilab or Jefferson Lab using specific routes to SLAC. The transport system consists of a base frame, isolation fixture and upper protective truss. The strongback cryomodule lifting fixture is described along with other supporting equipment used for both over-the-road transport and local (on-site) transport at Fermilab. Initially, analysis of fragile components and stability studies will be performed in order to assess the risk associated with over-the-road transport of a fully assembled cryomodule.

  19. The SLAC linear collider

    International Nuclear Information System (INIS)

    Richter, B.

    1985-01-01

    A report is given on the goals and progress of the SLAC Linear Collider. The author discusses the status of the machine and the detectors and give an overview of the physics which can be done at this new facility. He also gives some ideas on how (and why) large linear colliders of the future should be built

  20. Sleepless at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Dement, William (Stanford Sleep Disorders Center)

    2006-01-23

    Feeling tired? More than 30 million Americans suffer from sleep disorders. Nevertheless, as a society we remain largely ignorant of the significance of sleep in determining the quality of our waking lives. Dr. William Dement, Stanford Professor and one of the world's foremost experts on sleep and sleep deprivation, joins SLAC's Colloquium Series to present exciting new findings in the field of sleep research. You'll never sleep the same again!

  1. Beam parameter measurements for the SLAC linear collider

    International Nuclear Information System (INIS)

    Clendenin, J.E.; Blocker, C.; Breidenbach, M.

    1982-01-01

    A stable, closely-controlled, high-intensity, single-bunch beam will be required for the SLAC Linear Collider. The characteristics of short-pulse, low-intensity beams in the SLAC linac have been studied. A new, high-intensity thermionic gun, subharmonic buncher and S-band buncher/accelerator section were installed recently at SLAC. With these components, up to 10 11 electrons in a single S-band bunch are available for injection into the linac. the first 100-m accelerator sector has been modified to allow control of short-pulse beams by a model-driven computer program. Additional instrumentation, including a computerized energy analyzer and emittance monitor have been added at the end of the 100-m sector. The beam intensity, energy spectrum, emittance, charge distribution and the effect of wake fields in the first accelerator sector have been measured. The new source and beam control system will be described and the most recent results of the beam parameter measurements will be discussed

  2. SLAC Scanner Processor: a FASTBUS module for data collection and processing

    International Nuclear Information System (INIS)

    Brafman, H.; Glanzman, T.; Lankford, A.J.; Olsen, J.; Paffrath, L.

    1984-10-01

    A new, general purpose, programmable FASTBUS module, the SLAC Scanner Processor (SSP), is introduced. Both hardware and software elements of SSP operation are discussed. The role of the SSP within the upgraded Mark II Detector at SLAC is described

  3. A possible CO2 conducting and concentrating mechanism in plant stomata SLAC1 channel.

    Directory of Open Access Journals (Sweden)

    Qi-Shi Du

    Full Text Available BACKGROUND: The plant SLAC1 is a slow anion channel in the membrane of stomatal guard cells, which controls the turgor pressure in the aperture-defining guard cells, thereby regulating the exchange of water vapour and photosynthetic gases in response to environmental signals such as drought, high levels of carbon dioxide, and bacterial invasion. Recent study demonstrated that bicarbonate is a small-molecule activator of SLAC1. Higher CO(2 and HCO(3(- concentration activates S-type anion channel currents in wild-type Arabidopsis guard cells. Based on the SLAC1 structure a theoretical model is derived to illustrate the activation of bicarbonate to SLAC1 channel. Meanwhile a possible CO(2 conducting and concentrating mechanism of the SLAC1 is proposed. METHODOLOGY: The homology structure of Arabidopsis thaliana SLAC1 (AtSLAC1 provides the structural basis for study of the conducting and concentrating mechanism of carbon dioxide in SLAC1 channels. The pK(a values of ionizable amino acid side chains in AtSLAC1 are calculated using software PROPKA3.0, and the concentration of CO(2 and anion HCO(3(- are computed based on the chemical equilibrium theory. CONCLUSIONS: The AtSLAC1 is modeled as a five-region channel with different pH values. The top and bottom layers of channel are the alkaline residue-dominated regions, and in the middle of channel there is the acidic region surrounding acidic residues His332. The CO(2 concentration is enhanced around 10(4 times by the pH difference between these regions, and CO(2 is stored in the hydrophobic region, which is a CO(2 pool. The pH driven CO(2 conduction from outside to inside balances the back electromotive force and maintain the influx of anions (e.g. Cl(- and NO(3(- from inside to outside. SLAC1 may be a pathway providing CO(2 for photosynthesis in the guard cells.

  4. SLAC accelerator operations report: 1995--1997

    International Nuclear Information System (INIS)

    Erickson, R.; Allen, C.W.; Anderson, S.; Linebarger, W.; Stanek, M.

    1997-05-01

    Operational statistics for the linear accelerator programs at SLAC are presented, including run-time records for SLC and the fixed-target programs. Also included are summaries of reliability and maintenance-related statistics

  5. Physics results with polarized electrons at SLAC

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1996-03-01

    Polarized electron beams can play an important role in the dynamics of interactions at high energies. Polarized electron beams at SLAC have been an important part of the physics program since 1970, when they were first proposed for use in testing the spin structure of the proton. Since 1992, the SLAC linear accelerator and the SLC have operated solely with polarized electrons, providing data for tests of QCD in studies of the spin structure of the nucleon and tests of the electroweak sector of the Standard Model. In the following sections, the performance of the source is summarized, and some of the recent results using the polarized beams are discussed

  6. SLAC R and D toward a TeV Linear Collider

    International Nuclear Information System (INIS)

    Wilson, P.B.

    1988-10-01

    At CERN, KEK, Novosibirsk and SLAC, serious thought is being given to the design of linear colliders in the 0.5--2.0 TeV center-of-mass energy range. This paper reviews current progress at SLAC toward the design of such a collider. No attempt is made here to summarize ongoing work at the other laboratories. However, research on linear colliders is clearly an international effort, and success at SLAC will be greatly expedited by communication and cooperation with other laboratories in the US and abroad. In addition to major programs at the laboratories mentioned above, contributions relevant to linear collider design are being made at DESY, LAL (Orsay), LBL, LLNL and elsewhere. 49 refs., 6 tabs

  7. Support and utilization of the LSI-11 processor family at SLAC

    International Nuclear Information System (INIS)

    Kieffer, J.; Logg, C.A.; Farwell, D.E.

    1981-01-01

    Microcomputer systems based on the DEC LSI-11 processor family have been in use at SLAC for five years. They are used for a wide variety of applications. The support of these systems is divided into three general areas: engineering, maintenance, and software. Engineering specifies the system to match user requirements. SLAC has been able to design one general purpose system which can be tailored to fit many specific requirements. Maintenance provides system and component diagnostic services and repair. Software support includes software consulting services, assistance in systems design, and the development and support of special purpose operating systems and programs. These support functions are handled as subtasks by three teams in the SLAC Electronics Instrumentation Group. Each of these teams utilizes several LSI-11 systems in the performance of its primary tasks. They work closely together to jointly provide overall support for the larger SLAC community

  8. Development of the Virtual Visitor Center at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    McDunn, Ruth

    1999-11-17

    The Virtual Visitor Center (VVC) web site (www2.slac.stanford.edu/vvc) is a ''virtual'' version of the Visitor Center, a mini science museum that opened at SLAC in 1996. The VVC was made public in December 1998. Both centers contribute to SLAC mission regarding education of the next generation and increasing scientific awareness of the public. The site is designed to mimic the real visitor center and allow a larger audience to the information. The intent was to reach the 8th-12th grade audience. Considerable effort was made to organize the content, including color-coding graphical elements for each main topic area. Tables of contents, a search tool, several photo tours, as well as graphical and non-graphical menu bars allow users many methods of navigating the site. The site was developed over almost two years using an estimated .95 FTE, split between a program manager, graphic designer, content provider (theoretical physicist), and a summer intern (high school teacher). As of November 1999, the site consists of 1,147 files, 935 images, 3,080 internal hyperlinks, and 190 external hyperlinks. The site has had over 1 million hits between January and mid-October 1999 and averages about 600 page views each day. Future plans include bringing the web site into compliance with the W3Cs Web Content Accessibility guidelines, thoroughly integrating the glossary terms, continued incorporation of current research at SLAC, and adding more interactivity.

  9. Development of the Virtual Visitor Center at SLAC

    International Nuclear Information System (INIS)

    McDunn, Ruth

    1999-01-01

    The Virtual Visitor Center (VVC) web site (www2.slac.stanford.edu/vvc) is a ''virtual'' version of the Visitor Center, a mini science museum that opened at SLAC in 1996. The VVC was made public in December 1998. Both centers contribute to SLAC mission regarding education of the next generation and increasing scientific awareness of the public. The site is designed to mimic the real visitor center and allow a larger audience to the information. The intent was to reach the 8th-12th grade audience. Considerable effort was made to organize the content, including color-coding graphical elements for each main topic area. Tables of contents, a search tool, several photo tours, as well as graphical and non-graphical menu bars allow users many methods of navigating the site. The site was developed over almost two years using an estimated .95 FTE, split between a program manager, graphic designer, content provider (theoretical physicist), and a summer intern (high school teacher). As of November 1999, the site consists of 1,147 files, 935 images, 3,080 internal hyperlinks, and 190 external hyperlinks. The site has had over 1 million hits between January and mid-October 1999 and averages about 600 page views each day. Future plans include bringing the web site into compliance with the W3Cs Web Content Accessibility guidelines, thoroughly integrating the glossary terms, continued incorporation of current research at SLAC, and adding more interactivity

  10. Pulse modulator developments in support of klystron testing at SLAC

    International Nuclear Information System (INIS)

    Koontz, R.F.; Cassel, R.; Lamare, J. de; Ficklin, D.; Gold, S.; Harris, K.

    1993-01-01

    Several families of high power klystrons in S- and X-Band are being developed in the Klystron Laboratory at SLAC. To support these developments, a number of new pulse modulators are being designed from scratch, or upgraded from existing laboratory test modulators. This paper outlines the modulator parameters available in the SLAC Klystron Laboratory, and discuss two new modulators that are under construction

  11. SDSS-IV MaNGA: the spectroscopic discovery of strongly lensed galaxies

    Science.gov (United States)

    Talbot, Michael S.; Brownstein, Joel R.; Bolton, Adam S.; Bundy, Kevin; Andrews, Brett H.; Cherinka, Brian; Collett, Thomas E.; More, Anupreeta; More, Surhud; Sonnenfeld, Alessandro; Vegetti, Simona; Wake, David A.; Weijmans, Anne-Marie; Westfall, Kyle B.

    2018-06-01

    We present a catalogue of 38 spectroscopically detected strong galaxy-galaxy gravitational lens candidates identified in the Sloan Digital Sky Survey IV (SDSS-IV). We were able to simulate narrow-band images for eight of them demonstrating evidence of multiple images. Two of our systems are compound lens candidates, each with two background source-planes. One of these compound systems shows clear lensing features in the narrow-band image. Our sample is based on 2812 galaxies observed by the Mapping Nearby Galaxies at APO (MaNGA) integral field unit (IFU). This Spectroscopic Identification of Lensing Objects (SILO) survey extends the methodology of the Sloan Lens ACS Survey (SLACS) and BOSS Emission-Line Survey (BELLS) to lower redshift and multiple IFU spectra. We searched ˜1.5 million spectra, of which 3065 contained multiple high signal-to-noise ratio background emission-lines or a resolved [O II] doublet, that are included in this catalogue. Upon manual inspection, we discovered regions with multiple spectra containing background emission-lines at the same redshift, providing evidence of a common source-plane geometry which was not possible in previous SLACS and BELLS discovery programs. We estimate more than half of our candidates have an Einstein radius ≳ 1.7 arcsec, which is significantly greater than seen in SLACS and BELLS. These larger Einstein radii produce more extended images of the background galaxy increasing the probability that a background emission-line will enter one of the IFU spectroscopic fibres, making detection more likely.

  12. Review of trigger and on-line processors at SLAC

    International Nuclear Information System (INIS)

    Lankford, A.J.

    1984-07-01

    The role of trigger and on-line processors in reducing data rates to manageable proportions in e + e - physics experiments is defined not by high physics or background rates, but by the large event sizes of the general-purpose detectors employed. The rate of e + e - annihilation is low, and backgrounds are not high; yet the number of physics processes which can be studied is vast and varied. This paper begins by briefly describing the role of trigger processors in the e + e - context. The usual flow of the trigger decision process is illustrated with selected examples of SLAC trigger processing. The features are mentioned of triggering at the SLC and the trigger processing plans of the two SLC detectors: The Mark II and the SLD. The most common on-line processors at SLAC, the BADC, the SLAC Scanner Processor, the SLAC FASTBUS Controller, and the VAX CAMAC Channel, are discussed. Uses of the 168/E, 3081/E, and FASTBUS VAX processors are mentioned. The manner in which these processors are interfaced and the function they serve on line is described. Finally, the accelerator control system for the SLC is outlined. This paper is a survey in nature, and hence, relies heavily upon references to previous publications for detailed description of work mentioned here. 27 references, 9 figures, 1 table

  13. SLAC B Factory computing

    International Nuclear Information System (INIS)

    Kunz, P.F.

    1992-02-01

    As part of the research and development program in preparation for a possible B Factory at SLAC, a group has been studying various aspects of HEP computing. In particular, the group is investigating the use of UNIX for all computing, from data acquisition, through analysis, and word processing. A summary of some of the results of this study will be given, along with some personal opinions on these topics

  14. The SLAC lasertron project

    International Nuclear Information System (INIS)

    Sinclair, C.K.

    1986-10-01

    SLAC has a program underway to develop an efficient high power microwave source for accelerator applications employing a photoemission cathode, the so-called lasertron. After a brief discussion of the lasertron idea, the various elements of the current program are reviewed. A proof-of-principle experiment to build a 35 MW, 70% efficiency, S-band microwave source is nearing completion. Actual RF power testing is expected to begin in late 1986 or early 1987

  15. The SLAC polarized electron source

    International Nuclear Information System (INIS)

    Clendenin, J.E.; Alley, R.; Frisch, J.; Kotseroglou, T.; Mulhollan, G.; Schultz, D.; Tang, H.; Turner, J.; Yeremian, A.D.

    1997-08-01

    Since 1992, the SLAC 3-km linac has operated exclusively with polarized electrons. The polarized electron source is highly reliable, remotely operated and monitored, and able to produce a variety of electron bunch profiles for high-energy physics experiments. The source and its operating characteristics are described. Some implications drawn from the operating experience are discussed

  16. Historical Analysis of the Inorganic Chemistry Curriculum Using ACS Examinations as Artifacts

    Science.gov (United States)

    Srinivasan, Shalini; Reisner, Barbara A.; Smith, Sheila R.; Stewart, Joanne L.; Johnson, Adam R.; Lin, Shirley; Marek, Keith A.; Nataro, Chip; Murphy, Kristen L.; Raker, Jeffrey R.

    2018-01-01

    ACS Examinations provide a lens through which to examine historical changes in topic coverage via analyses of course-specific examinations. This study is an extension of work completed previously by the ACS Exams Research Staff and collaborators in general chemistry, organic chemistry, and physical chemistry to explore content changes in the…

  17. Latest Results in SLAC 75-MW PPM Klystrons

    International Nuclear Information System (INIS)

    Sprehn, D.; Caryotakis, G.; Haase, A.; Jongewaard, E.; Laurent, L.; Pearson, C.; Phillips, R.

    2006-01-01

    75 MW X-band klystrons utilizing Periodic Permanent Magnet (PPM) focusing have been undergoing design, fabrication and testing at the Stanford Linear Accelerator Center (SLAC) for almost nine years. The klystron development has been geared toward realizing the necessary components for the construction of the Next Linear Collider (NLC). The PPM devices built to date which fit this class of operation consist of a variety of 50 MW and 75 MW devices constructed by SLAC, KEK (Tsukuba, Japan) and industry. All these tubes follow from the successful SLAC design of a 50 MW PPM klystron in 1996. In 2004 the latest two klystrons were constructed and tested with preliminary results reported at EPAC2004. The first of these two devices was tested to the full NLC specifications of 75 MW, 1.6 microseconds pulse length, and 120 Hz. This 14.4 kW average power operation came with a tube efficiency >50%. The most recent testing of these last two devices will be presented here. Design and manufacturing issues of the latest klystron, due to be tested by the Fall of 2005, are also discussed

  18. Review of the SLAC and Les Houches workshops

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1994-12-01

    Polarized Electron Source workshops have been held at varying intervals, beginning in 1983 when Charles Sinclair convened the first at SLAC. Since that time, three workshops were held in conjunction with the International Spin Symposia and two at other occasions. The increasing importance of polarized electron beams at accelerators has stimulated interest in these workshops. Two workshops have been held since the last International Spin Symposium in Nagoya. In 1993, a workshop was held at SLAC, and in 1994 at Les Houches, a polarized electron beam session was held as part of a polarized beam and targets workshop. This report summarizes highlights from the latter two workshops

  19. SLAC accelerator operations report: 1992-1995

    International Nuclear Information System (INIS)

    Erickson, R.; Allen, C.W.; Inman, T.K.; Linebarger, W.; Stanek, M.

    1995-05-01

    Operational statistics for the linear accelerator programs at SLAC are presented, including run-time records for the SLC, FFTB, and fixed target programs. Also included are summaries of reliability and maintenance-related statistics and a discussion of the analysis tools used to study error messages generated by the control system

  20. Homologue Structure of the SLAC1 Anion Channel for Closing Stomata in Leaves

    Energy Technology Data Exchange (ETDEWEB)

    Y Chen; L Hu; M Punta; R Bruni; B Hillerich; B Kloss; B Rost; J Love; S Siegelbaum; W Hendrickson

    2011-12-31

    The plant SLAC1 anion channel controls turgor pressure in the aperture-defining guard cells of plant stomata, thereby regulating the exchange of water vapour and photosynthetic gases in response to environmental signals such as drought or high levels of carbon dioxide. Here we determine the crystal structure of a bacterial homologue (Haemophilus influenzae) of SLAC1 at 1.20 {angstrom} resolution, and use structure-inspired mutagenesis to analyse the conductance properties of SLAC1 channels. SLAC1 is a symmetrical trimer composed from quasi-symmetrical subunits, each having ten transmembrane helices arranged from helical hairpin pairs to form a central five-helix transmembrane pore that is gated by an extremely conserved phenylalanine residue. Conformational features indicate a mechanism for control of gating by kinase activation, and electrostatic features of the pore coupled with electrophysiological characteristics indicate that selectivity among different anions is largely a function of the energetic cost of ion dehydration.

  1. Luminosity enhancements at SLAC

    International Nuclear Information System (INIS)

    Coward, D.H.

    1984-04-01

    Several ideas are discussed that have been proposed to improve the luminosity at the SPEAR and PEP electron-positron storage rings and to insure good luminosity at the SLAC Linear Collider. There have been two proposals studied recently for SPEAR: a Microbeta insertion using Samarium Cobalt permanent magnets, and a Minibeta insertion using conventional quadrupole magnets. The notations Microbeta and minibeta used here are somewhat arbitrary since the front faces of the first quadrupole magnets for both insertions are at nearly the same distance from the interaction point

  2. Acceleration of high charge density electron beams in the SLAC linac

    International Nuclear Information System (INIS)

    Sheppard, J.C.; Clendenin, J.E.; Jobe, R.K.; Lueth, V.G.; Millich, A.; Ross, M.C.; Seeman, J.T.; Stiening, R.F.

    1984-01-01

    The SLAC Linear Collider (SLC) will require both electron and positron beams of very high charge density and low emittance to be accelerated to about 50 GeV in the SLAC 3-km linac. The linac is in the process of being improved to meet this requirement. The program to accelerate an electron beam of high charge density through the first third of the SLC linac is described and the experimental results are discussed. 7 references, 5 figures

  3. SLAC Linac Preparations for FACET

    International Nuclear Information System (INIS)

    Erickson, Roger

    2011-01-01

    The SLAC 3km linear electron accelerator has been cut at the two-thirds point to provide beams to two independent programs. The last third provides the electron beam for the Linac Coherent Light Source (LCLS), leaving the first two-thirds available for FACET, the new experimental facility for accelerator science and test beams. In this paper, we describe this separation and projects to prepare the linac for the FACET experimental program.

  4. SLACINPT - a FORTRAN program that generates boundary data for the SLAC gun code

    International Nuclear Information System (INIS)

    Michel, W.L.; Hepburn, J.D.

    1982-03-01

    The FORTRAN program SLACINPT was written to simplify the preparation of boundary data for the SLAC gun code. In SLACINPT, the boundary is described by a sequence of straight line or arc segments. From these, the program generates the individual boundary mesh point data, required as input by the SLAC gun code

  5. Linac design for the LCLS project at SLAC

    International Nuclear Information System (INIS)

    Bharadwaj, V.K.; Bane, K.; Clendenin, J.

    1997-05-01

    The Linac Coherent Light Source (LCLS) at SLAC is being designed to produce intense, coherent 0.15-nm x-rays. These x-rays will be produced by a single pass of a 15 GeV bunched electron beam through a long undulator. Nominally, the bunches have a charge of 1 nC, normalized transverse emittances of less than 1.5π mm-mr and an rms bunch length of 20 μm. The electron beam will be produced using the last third of the SLAC 3-km linac in a manner compatible with simultaneous operation of the remainder of the linac for PEP-II. The linac design necessary to produce an electron beam with the required brightness for LCLS is discussed, and the specific linac modifications are described

  6. Status of the SLAC Linear Collider Project

    International Nuclear Information System (INIS)

    Stiening, R.

    1983-01-01

    The SLAC Linear Collider Project has two principal goals. The first is to serve as a prototype for a future very high energy linear electron-positron collider. The second is to quickly, at low cost, achieve sufficient luminosity at 100 GeV center-of-mass energy to explore the physics of the Z 0 . The first goal is important to the future of electron-positron physics because the rapid increase of synchrotron radiation with energy causes the cost of circular storage ring colliders to whereas the cost of linear colliders increases only in proportion to the center-of-mass energy. The second is important because the existance at SLAC of a linear accelerator which can be converted at low cost to collider operation makes possible a unique opportunity to quickly achieve 100 GeV center-of-mass collisions. At the design luminosity of 6.0 x 10 30 many thousands of Z 0 decays should be observed in each day of operation

  7. GLAST beam test at SLAC

    International Nuclear Information System (INIS)

    Engovatov, D.; Anthony, P.; Atwood, W.

    1996-10-01

    In May and June, a beam test for GLAST calorimeter technologies was conducted. A parasitic low intensity electron/tagged photon beam line into the End Station A at SLAC was commissioned and used. The preliminary stage of the test was devoted to measuring the performance of the parasitic beam. In the main test we studied the response of GLAST prototype CsI and scintillating fiber calorimeters to the electrons and photons. Results of this work are discussed

  8. The sloan lens ACS survey. VI. Discovery and analysis of a double Einstein ring

    NARCIS (Netherlands)

    Gavazzi, Raphael; Treu, Tommaso; Koopmans, Leon V. E.; Bolton, Adam S.; Moustakas, Leonidas A.; Burles, Scott; Marshall, Philip J.

    2008-01-01

    We report the discovery of two concentric Einstein rings around the gravitational lens SDSS J0946+ 1006. The main lens is at redshift z(l) = 0.222, while the inner ring ( 1) is at redshift z(s1) 0.609 (R-Ein1 = 1.43 '' +/- 0.01 ''). The wider image separation ( R-Ein2 = 2.07 '' +/- 0.02 '') of the

  9. Molecular Evolution of Slow and Quick Anion Channels (SLACs and QUACs/ALMTs).

    Science.gov (United States)

    Dreyer, Ingo; Gomez-Porras, Judith Lucia; Riaño-Pachón, Diego Mauricio; Hedrich, Rainer; Geiger, Dietmar

    2012-01-01

    Electrophysiological analyses conducted about 25 years ago detected two types of anion channels in the plasma membrane of guard cells. One type of channel responds slowly to changes in membrane voltage while the other responds quickly. Consequently, they were named SLAC, for SLow Anion Channel, and QUAC, for QUick Anion Channel. Recently, genes SLAC1 and QUAC1/ALMT12, underlying the two different anion current components, could be identified in the model plant Arabidopsis thaliana. Expression of the gene products in Xenopus oocytes confirmed the quick and slow current kinetics. In this study we provide an overview on our current knowledge on slow and quick anion channels in plants and analyze the molecular evolution of ALMT/QUAC-like and SLAC-like channels. We discovered fingerprints that allow screening databases for these channel types and were able to identify 192 (177 non-redundant) SLAC-like and 422 (402 non-redundant) ALMT/QUAC-like proteins in the fully sequenced genomes of 32 plant species. Phylogenetic analyses provided new insights into the molecular evolution of these channel types. We also combined sequence alignment and clustering with predictions of protein features, leading to the identification of known conserved phosphorylation sites in SLAC1-like channels along with potential sites that have not been yet experimentally confirmed. Using a similar strategy to analyze the hydropathicity of ALMT/QUAC-like channels, we propose a modified topology with additional transmembrane regions that integrates structure and function of these membrane proteins. Our results suggest that cross-referencing phylogenetic analyses with position-specific protein properties and functional data could be a very powerful tool for genome research approaches in general.

  10. Molecular evolution of slow and quick anion channels (SLACs and QUACs/ALMTs

    Directory of Open Access Journals (Sweden)

    Ingo eDreyer

    2012-11-01

    Full Text Available Electrophysiological analyses conducted about 25 years ago detected two types of anion channels in the plasma membrane of guard cells. One type of channel responds slowly to changes in membrane voltage while the other responds quickly. Consequently, they were named SLAC, for SLow Anion Channel, and QUAC, for QUick Anion Channel. Recently, genes SLAC1 and QUAC1/ALMT12, underlying the two different anion current components, could be identified in the model plant Arabidopsis thaliana. Expression of the gene products in Xenopus oocytes confirmed the quick and slow current kinetics. In this study we provide an overview on our current knowledge on slow and quick anion channels in plants and analyze the molecular evolution of ALMT/QUAC-like and SLAC-like channels. We discovered fingerprints that allow screening databases for these channel types and were able to identify 192 (177 non-redundant SLAC-like and 422 (402 non-redundant ALMT/QUAC-like proteins in the fully sequenced genomes of 32 plant species. Phylogenetic analyses provided new insights into the molecular evolution of these channel types. We also combined sequence alignment and clustering with predictions of protein features, leading to the identification of known conserved phosphorylation sites in SLAC1-like channels along with potential sites that have not been yet experimentally confirmed. Using a similar strategy to analyze the hydropathicity of ALMT/QUAC-like channels, we propose a modified topology with additional transmembrane regions that integrates structure and function of these membrane proteins. Our results suggest that cross-referencing phylogenetic analyses with position-specific protein properties and functional data could be a very powerful tool for genome research approaches in general.

  11. Proceedings of the SLAC/KEK ATF lattice workshop

    International Nuclear Information System (INIS)

    Urakawa, Junji

    1993-04-01

    The SLAC/KEK ATF Lattice Workshop was held on December 8-11, 1992 at KEK, National Laboratory for High Energy Physics. The purpose of this workshop is to critically review the ATF lattice design for any possible improvements, and also to bring SLAC colleagues up to date on recent progress at KEK. At KEK studies on intense multi-bunch beam acceleration and emittance reduction have been actively pursued, evolving into the ATF project since 1990. In 1991 we have launched a large scale reconstruction of the experimental hall. This is to build the shielded housing for the 1.54 GeV injector linac and the test damping ring. Our plan is to begin construction of the linac in March 1993. Some results from the discussions during the Workshop have been already incorporated in the revised ATF lattice design. (J.P.N.)

  12. Multi-Device Knob Utility for LCLS at SLAC

    International Nuclear Information System (INIS)

    Zelazny, Michael

    2009-01-01

    At the SLAC National Accelerator Laboratory (SLAC) the Controls Department (CD) has developed a new Multi-Device Knob Utility (MKB) based on the Experimental Physics and Industrial Control System (EPICS) toolkit for controlling one or more Process Variables (PVs) in unison, or simultaneously, from a physical knob located in the control room, or from various software tools such as the EPICS Extensible Display Manager (EDM) or a Swing slider in Java. A group of devices are hooked up to a knob, and then the value written to the devices is a simple function of the value of the knob. This is used, most commonly, to create a bump in the electron beam for the Linac Coherent Light Source (LCLS). Control system variables typically controlled are magnetic fields, phases, and timing offsets. This paper describes the technologies used to implement this utility.

  13. Wakefields in SLAC linac collimators

    Directory of Open Access Journals (Sweden)

    A. Novokhatski

    2014-12-01

    Full Text Available When a beam travels near collimator jaws, it gets an energy loss and a transverse kick due to the backreaction of the beam field diffracted from the jaws. The effect becomes very important for an intense short bunch when a tight collimation of the background beam halo is required. In the Linac Coherent Light Source at SLAC a collimation system is used to protect the undulators from radiation due to particles in the beam halo. The halo is most likely formed from gun dark current or dark current in some of the accelerating sections. However, collimators are also responsible for the generation of wake fields. The wake field effect from the collimators not only brings an additional energy jitter and change in the trajectory of the beam, but it also rotates the beam on the phase plane, which consequently leads to a degradation of the performance of the Free Electron Laser at the Linac Coherent Light Source. In this paper, we describe a model of the wake field radiation in the SLAC linac collimators. We use the results of a numerical simulation to illustrate the model. Based on the model, we derive simple formulas for the bunch energy loss and the average kick. We also present results from experimental measurements that confirm our model.

  14. RF pulse compression in the NLC test accelerator at SLAC

    International Nuclear Information System (INIS)

    Lavine, T.L.

    1995-01-01

    At the Stanford Linear Accelerator Center (SLAC), the authors are designing a Next Linear Collider (NLC) with linacs powered by X-band klystrons with rf pulse compression. The design of the linac rf system is based on X-band prototypes which have been tested at high power, and on a systems-integration test - the Next Linear Collider Test Accelerator (NLCTA) - which is currently under construction at SLAC. This paper discusses some of the systems implications of rf pulse compression, and the use of pulse compression in the NLCTA, both for peak power multiplication and for controlling, by rf phase modulation, intra-pulse variations in the linac beam energy

  15. Identification and biochemical analysis of Slac2-c/MyRIP as a Rab27A-, myosin Va/VIIa-, and actin-binding protein.

    Science.gov (United States)

    Kuroda, Taruho S; Fukuda, Mitsunori

    2005-01-01

    Slac2-c/MyRIP is a specific Rab27A-binding protein that contains an N-terminal synaptotagmin-like protein (Slp) homology domain (SHD, a newly identified GTP-Rab27A-binding motif), but in contrast to the Slp family proteins, it lacks C-terminal tandem C2 domains. In vitro Slac2-c simultaneously directly interacts with both Rab27A and an actin-based motor protein, myosin Va, via its N-terminal SHD and middle region, respectively, consistent with the fact that the overall structure of Slac2-c is similar to that of Slac2-a/melanophilin, a linker protein between Rab27A and myosin Va in the melanosome transport in melanocytes. Unlike Slac2-a, however, the middle region of Slac2-c interacts with two types of myosins, myosin Va and myosin VIIa. In addition, the most C-terminal part of both Slac2-a and Slac2-c functions as an actin-binding domain: it directly interacts with globular and fibrous actin in vitro, and the actin-binding domain of Slac2-a and Slac2-c colocalizes with actin filaments when it is expressed in living cells (i.e., PC12 cells and mouse melanocytes). In this chapter we describe the methods that have been used to analyze the protein-protein interactions of Slac2-c, specifically with Rab27A, myosin Va/VIIa, and actin.

  16. 6D Phase Space Measurements at the SLAC Gun Test Facility

    CERN Document Server

    Schmerge, J

    2003-01-01

    Proposed fourth generation light sources using SASE FELs to generate short pulse, coherent X-rays require demonstration of high brightness electron sources. The Gun Test Facility (GTF) at SLAC was built to test high brightness sources for the proposed Linac Coherent Light Source at SLAC. The GTF is composed of an Sband photocathode rf gun with a Cu cathode, emittance compensating solenoid, single 3 m SLAC linac section and e-beam diagnostic section with a UV drive laser system. The longitudinal emittance exiting the gun has been determined by measuring the energy spectrum downstream of the linac as a function of the linac phase. The e-beam pulse width, correlated and uncorrelated energy spread at the linac entrance have been fit to the measured energy spectra using a least square error fitting routine. The fit yields a pulse width of 2.9 ps FWHM for a 4.3 ps FWHM laser pulse width and 2% rms correlated energy spread with 0.07% rms uncorrelated energy spread. The correlated energy spread is enhanced in the lin...

  17. SLAC physicists develop test for string theory

    CERN Multimedia

    Yajnik, Juhi

    2006-01-01

    "Under certain conditions, string theory solves many of the questions wracking the minds of physicists, but until recently it had one major flaw - it could not be tested. SLAC (Stanford Linear Accelerator Center) scientists have found a way to test this revolutionary theory, which posits that there are 10 or 11 dimensions in our universe" (1 page)

  18. How robust are the constraints on cosmology and galaxy evolution from the lens-redshift test?

    Energy Technology Data Exchange (ETDEWEB)

    Capelo, Pedro R [Astronomy Department, Yale University, PO Box 208101, New Haven, CT 06520-8101 (United States); Natarajan, Priyamvada [Astronomy Department, Yale University, PO Box 208101, New Haven, CT 06520-8101 (United States)

    2007-12-15

    The redshift distribution of galaxy lenses in known gravitational lens systems provides a powerful test that can potentially discriminate amongst cosmological models. However, applications of this elegant test have been curtailed by two factors: our ignorance of how galaxies evolve with redshift, and the absence of methods to deal with the effect of incomplete information in lensing systems. In this paper, we investigate both issues in detail. We explore how to extract the properties of evolving galaxies, assuming that the cosmology is well determined by other techniques. We propose a new nested Monte Carlo method to quantify the effects of incomplete data. We apply the lens-redshift test to an improved sample of seventy lens systems derived from recent observations, primarily from the SDSS, SLACS and the CLASS surveys. We find that the limiting factor in applying the lens-redshift test derives from poor statistics, including incomplete information samples and biased sampling. Many lenses that uniformly sample the underlying true image separation distribution will be needed to use this test as a complementary method to measure the value of the cosmological constant or the properties of evolving galaxies. Planned future surveys by missions like the SNAP satellite or LSST are likely to usher in a new era for strong lensing studies that utilize this test. With expected catalogues of thousands of new strong lenses, the lens-redshift test could offer a powerful tool to probe cosmology as well as galaxy evolution.

  19. How robust are the constraints on cosmology and galaxy evolution from the lens-redshift test?

    International Nuclear Information System (INIS)

    Capelo, Pedro R; Natarajan, Priyamvada

    2007-01-01

    The redshift distribution of galaxy lenses in known gravitational lens systems provides a powerful test that can potentially discriminate amongst cosmological models. However, applications of this elegant test have been curtailed by two factors: our ignorance of how galaxies evolve with redshift, and the absence of methods to deal with the effect of incomplete information in lensing systems. In this paper, we investigate both issues in detail. We explore how to extract the properties of evolving galaxies, assuming that the cosmology is well determined by other techniques. We propose a new nested Monte Carlo method to quantify the effects of incomplete data. We apply the lens-redshift test to an improved sample of seventy lens systems derived from recent observations, primarily from the SDSS, SLACS and the CLASS surveys. We find that the limiting factor in applying the lens-redshift test derives from poor statistics, including incomplete information samples and biased sampling. Many lenses that uniformly sample the underlying true image separation distribution will be needed to use this test as a complementary method to measure the value of the cosmological constant or the properties of evolving galaxies. Planned future surveys by missions like the SNAP satellite or LSST are likely to usher in a new era for strong lensing studies that utilize this test. With expected catalogues of thousands of new strong lenses, the lens-redshift test could offer a powerful tool to probe cosmology as well as galaxy evolution

  20. RF pulse compression in the NLC test accelerator at SLAC

    International Nuclear Information System (INIS)

    Lavine, T.L.

    1995-01-01

    At the Stanford Linear Accelerator Center (SLAC), we are designing a Next Linear Collider (NLC) with linacs powered by X-band klystrons with rf pulse compression. The design of the linac rf system is based on X-band prototypes which have been tested at high power, and on a systems-integration test---the Next Linear Collider Test Accelerator (NLCTA)---which is currently under construction at SLAC. This paper discusses some of the systems implications of rf pulse compression, and the use of pulse compression in the NLCTA, both for peak power multiplication and for controlling, by rf phase modulation, intra-pulse variations in the linac beam energy. copyright 1995 American Institute of Physics

  1. SLAC RF Source Research at X-Band

    International Nuclear Information System (INIS)

    Sprehn, D.

    2003-01-01

    X-band klystrons capable of 75 MW and utilizing either solenoidal or Periodic Permanent Magnet (PPM) focusing are undergoing design, fabrication and testing at the Stanford Linear Accelerator Center (SLAC). The klystron development is part of an effort to realize components necessary for the construction of the Next Linear Collider (NLC). SLAC has developed a solenoidal-focused X-band klystron which is currently the workhorse of high power component testing for the NLC. A state-of-the-art modulator will drive eight of these tubes which, in turn, will power an rf distribution system referred to as the ''8-pack'' in order to test these modulators and waveguide components. Eventually, in an interest to save millions of dollars per year in the operational cost of the NLC, these tubes will be replaced by PPM klystrons. The PPM devices built to date which fit this class of operation consist of a variety of 50 MW and 75 MW devices constructed by SLAC, KEK (Tsukuba, Japan ), and industry. These tubes follow from the successful 50 MW PPM design of 1996. Recent testing of this particular tube at wider pulsewidths has reached 50 MW at 55 % efficiency, 2.4 μs and 60 Hz. Two 50 MW PPM klystrons produced by industry have been delivered to SLAC. One of these devices arrived with a vacuum suitable for test. Testing during 2001 revealed a serious, but curious, vacuum response which limited the operation to an rf output of ∼40 MW. A 75 MW PPM klystron prototype was first constructed in 1997 and later modified in 1999 to eliminate oscillations. This tube has reached the NLC design target of 75 MW at 1.5 μs though at a significantly reduced rep rate. Two new 75 MW PPM klystrons were constructed and tested in 2002 after a diode was successfully tested in 2001. The new design was aimed at reducing the cost and increasing the reliability of such high-energy devices. The rf circuit and beam focusing for one of these devices was built by industry and incorporated into one of the tubes

  2. Development of X-band klystron technology at SLAC

    International Nuclear Information System (INIS)

    Caryotakis, G.

    1997-05-01

    The SLAC design for a 1-TeV collider (NLC) requires klystrons with a performance which is well beyond the state-of-the-art for microwave tubes in the United States or abroad. The electrical specifications for the NLC klystrons are not fully established, but they are approximately as follows: Frequency, 11.4 GHz; Peak Power, 75 MW; Pulse Length, 1.5 μs; Repetition Rate, 180 Hz; Gain, 50 dB; Efficiency, (including beam focusing) 50%. SLAC is in the seventh year of a program to develop these klystrons. The choice of X-band as the operating frequency, along with the sheer size of the NLC, have resulted in some new, most demanding standards for the klystrons which may power this future machine. These are related to the overall efficiency required, to the high rf gradients that must be supported at the output circuit without vacuum breakdown, and to the manufacturing cost of the 5,000-10,000 klystrons needed for the collider

  3. New features in MADX thin-lens tracking module

    CERN Document Server

    Sun, Y; CERN. Geneva. BE Department

    2010-01-01

    In this note, we introduce several new features of the MADX thin-lens tracking module, which include the new element AC dipole, the new feature ‘NOISE’ attached to the class ‘multipole’, and the offset of the ‘aperture’ model. We also present simulation results for the benchmark between different codes, and some applications with examples.

  4. New features in MADX thin-lens tracking module

    CERN Document Server

    Sun, YP; CERN. Geneva. BE Department

    2010-01-01

    In this note, we introduce several new features of the MADX thin-lens tracking module, which include the new element AC dipole, the new feature ‘NOISE’attached to the class ‘multipole’, and the offset of the ‘aperture’ model. We also present simulation results for the benchmark between different codes, and some applications with examples.

  5. Present and future developments on the SLAC three-kilometer accelerator

    International Nuclear Information System (INIS)

    Loew, G.A.

    1977-07-01

    A review is given of the innovations which have recently been made or are being planned on the SLAC three-kilometer accelerator. A brief review of overall performance statistics is given, the beam is followed from its origin to the experimental areas. The injector with its new polarized guns, some highlights of klystron research, the SLED or SLAC Energy Development Program, which will boost the electron energy into the 30 to 40 GeV range, and some associated beam loading and beam breakup implications are described. Following these, a brief survey of other microwave developments is given. Some of the innovations being implanted in computer control are summarized, and the changes being planned for the generation and delivery of e +- beams to the PEP ring are discussed

  6. Proceedings of the SLAC/KEK linear collider workshop on damping ring

    International Nuclear Information System (INIS)

    Urakawa, J.; Yoshioka, M.

    1992-07-01

    Since the SLAC/KEK joint meeting was first held at SLAC in March 1987, we have had such a meeting annually with the present one the 6th. This meeting is planned to discuss the damping ring issue in particular. We have ever stressed the importance of study of damping rings and considered construction of a test damping ring as key issue for the ATF project, since we started construction of the ATF in 1987. In 1991 we had large-scale reconstruction of a building to make a shielded area where a 1.54 GeV injector linac for the ring is to be installed. (J.P.N.)

  7. SLAC High Gradient Testing of a KEK X-Band Accelerator Structure

    International Nuclear Information System (INIS)

    Loewen, Rod

    2000-01-01

    The high accelerating gradients required for future linear colliders demands a better study of field emission and RF breakdown in accelerator structures. Changes in structure geometry, vacuum pumping, fabrication methods, and surface finish can all potentially impact the conditioning process, dark current emission, and peak RF power handling capability. Recent tests at SLAC of KEK's ''M2'' travelling wave x-band accelerator section provides an opportunity to investigate some of these effects by comparing its performance to previously high power tested structures at SLAC. In addition to studying ultimate power limitations, this test also demonstrates the use of computer automated conditioning to reach practical, achievable gradients

  8. SLAC pulsed X-ray facility

    Science.gov (United States)

    Ipe, N. E.; McCall, R. C.; Baker, E. D.

    1986-05-01

    The Stanford Linear Accelerator Center (SLAC) operates a high energy (up to 33 GeV) linear accelerator delivering pulses up to a few microseconds wide. The pulsed nature of the electron beam creates problems in the detection and measurement of radiation both from the accelerator beam and the klystrons that provide the RF power for the accelerator. Hence, a pulsed X-ray facility has been built at SLAC mainly for the purpose of testing the response of different radiation detection instruments to pulsed radiation fields. The X-ray tube consists of an electron gun with a control grid. This provides a stream of pulsed electrons that can be accelerated towards a confined target-window. The window is made up of aluminum 0.051 cm (20 mils) thick, plated on the vacuum side with a layer of gold 0.0006 cm (1/4 mil) thick. The frequency of electron pulses can be varied by an internal pulser from 60 to 360 pulses per second with pulse widths of 360 ns to 5 ms. The pulse amplitude can be varied over a wide range of currents. An external pulser can be used to obtain other frequencies or special pulse shapes. The voltage across the gun can be varied from 0 to 100 kV. The major part of the X-ray tube is enclosed in a large walk-in-cabinet made of 1.9 cm (3/4 in) plywood and lined with 0.32 cm (1/8 in) lead to make a very versatile facility.

  9. SLAC pulsed x-ray facility

    International Nuclear Information System (INIS)

    Ipe, N.E.; McCall, R.C.; Baker, E.D.

    1986-05-01

    The Stanford Linear Accelerator Center (SLAC) operates a high energy (up to 33 GeV) linear accelerator delivering pulses up to a few microseconds wide. The pulsed nature of the electron beam creates problems in the detection and measurement of radiation both from the accelerator beam and the klystrons that provide the rf power for the accelerator. Hence, a pulsed x-ray facility has been built at SLAC mainly for the purpose of testing the response of different radiation detection instruments to pulsed radiation fields. The x-ray tube consists of an electron gun with a control grid. This provides a stream of pulsed electrons that can be accelerated towards a confined target-window. The window is made up of aluminium 0.051 cm (20 mils) thick, plated on the vacuum side with a layer of gold 0.0006 cm (1/4 mil) thick. The frequency of electron pulses can be varied by an internal pulser from 60 to 360 pulses per second with pulse widths of 360 ns to 5 μs. The pulse amplitude can be varied over a wide range of currents. An external pulser can be used to obtain other frequencies or special pulse shapes. The voltage across the gun can be varied from 0 to 100 kV. The major part of the x-ray tube is enclosed in a large walk-in-cabinet made of 1.9 cm (3/4 in) plywood and lined with 0.32 cm (1/8 in) lead to make a very versatile facility. 3 refs., 5 figs

  10. Progress report on the SLAC Linear Collider

    International Nuclear Information System (INIS)

    Rees, J.

    1986-06-01

    The SLAC Linear Collider project (SLC) is reported as being near completion. The performance specifications are tabulated both for the initial form and for eventual goals. Various parts of the SLC are described and the status of their construction is reported, including the front end electron gun and booster, the linac, damping ring, positron source, SLC arcs, and conventional facilities. 5 refs., 12 figs

  11. Analysis of incidence and related factors on effusion of anterior chamber after phacoemulsification combined with intraocular lens implantation

    Directory of Open Access Journals (Sweden)

    Bing-Bing Zhao

    2018-02-01

    Full Text Available AIM: To investigate the incidence and related factors on effusion of anterior chamber(ACafter phacoemulsification(PEcombined with intraocular lens(IOLimplantation. METHODS: Totally 359 cases of cataract(375 eyesunderwent PE combined with IOL implantation were collected in our hospital. The incidence of AC exudation after operation and related factors were analyzed by single factor and multiple logistic regression analysis. RESULTS: The group was included in 359 cases(375 eyes. The incidence of postoperative AC exudation in the study group was 5.9%(22/375. The preoperative intraocular pressure(IOP, visual acuity before and after surgery, nuclear grades, posterior capsular rupture(PCRrate and ultrasonic accumulated energy complex parameter(AECPof the study group showed statistically significant difference compared with the control group(all P21mmHg, intraoperative pupil diameter 7.25(%×min, the lens nucleus grade ≥ IV were risk factors of AC exudation after PE combined with IOL implantation in patients with cataract(all P21mmHg, ultrasound AECP >7.25 were independent risk factors of AC exudation after PE combined with IOL implantation in patients with cataract(all PCONCLUSION: High myopia, glaucoma, uveitis, the lens nucleus grade ≥ IV, the incidence of intraoperative PCR, preoperative IOP>21mmHg, ultrasonic AECP>7.25 are independent risk factors of AC exudation after PE combined with IOL implantation in patients with cataract, with such risk factors in patients with cataract should be paid closely attention and timely diagnosis and treatment in clinic.

  12. Design of a semi-custom integrated circuit for the SLAC SLC timing control system

    International Nuclear Information System (INIS)

    Linstadt, E.

    1984-10-01

    A semi-custom (gate array) integrated circuit has been designed for use in the SLAC Linear Collider timing and control system. The design process and SLAC's experiences during the phases of the design cycle are described. Issues concerning the partitioning of the design into semi-custom and standard components are discussed. Functional descriptions of the semi-custom integrated circuit and the timing module in which it is used are given

  13. The SLAC linear collider

    International Nuclear Information System (INIS)

    Phinney, N.

    1992-01-01

    The SLAC Linear Collider has begun a new era of operation with the SLD detector. During 1991 there was a first engineering run for the SLD in parallel with machine improvements to increase luminosity and reliability. For the 1992 run, a polarized electron source was added and more than 10,000 Zs with an average of 23% polarization have been logged by the SLD. This paper discusses the performance of the SLC in 1991 and 1992 and the technical advances that have produced higher luminosity. Emphasis will be placed on issues relevant to future linear colliders such as producing and maintaining high current, low emittance beams and focusing the beams to the micron scale for collisions. (Author) tab., 2 figs., 18 refs

  14. SLAC Users Bulletin No. 102, November 1985-April 1986

    International Nuclear Information System (INIS)

    Keller, L.P.; Edminster, D.

    1986-01-01

    The status experimental activities at SLAC is reported, including the long-range schedule and a list of approved high-energy experiments. Work on PEP, SPEAR, and the SLC is included, as well as computing. Such operational data as operating hours and experimental hours are given.

  15. Measurement of the longitudinal wakefield and the bunch shape in the SLAC linac

    International Nuclear Information System (INIS)

    Bane, K.L.F.; Decker, F.J.; Seeman, J.T.; Zimmermann, F.

    1997-05-01

    The authors report on measurements of the bunch energy spectrum at the end of the SLAC linac. Using the spectra obtained for two different linac rf phases they obtain both the bunch induced voltage and the longitudinal distribution of the bunch. The measurement results are compared with theoretical predictions. In particular, the induced voltage is in good agreement with that obtained using the calculated wake function for the SLAC linac. This measurement technique may be useful for monitoring changes of the linac bunch shape in the SLC

  16. SLAC-Linac-Collider (SLC) Project

    International Nuclear Information System (INIS)

    Wiedemann, H.

    1981-02-01

    The proposed SLAC Linear Collider Project (SLC) and its features are described in this paper. In times of ever increasing costs for energy the electron storage ring principle is about to reach its practical limit. A new class of colliding beam beam facilities, the Linear Colliders, are getting more and more attractive and affordable at very high center-of-mass energies. The SLC is designed to be a poineer of this new class of colliding beam facilities and at the same time will serve as a valuable tool to explore the high energy physics at the level of 100 GeV in the center-of-mass system

  17. The SLAC polarized electron source

    International Nuclear Information System (INIS)

    Tang, H.; Alley, R.; Frisch, J.

    1995-06-01

    The SLAC polarized electron source employs a photocathode DC high voltage gun with a loadlock and a YAG pumped Ti:sapphire laser system for colliding beam experiments or a flash lamp pumped Ti:sapphire laser for fixed target experiments. It uses a thin, strained GaAs(100) photocathode, and is capable of producing a pulsed beam with a polarization of ≥80% and a peak current exceeding 10 A. Its operating efficiency has reached 99%. The physics and technology of producing high polarization electron beams from a GaAs photocathode will be reviewed. The prospects of realizing a polarized electron source for future linear colliders will also be discussed

  18. Shower Counters for SLAC experiments E142/E143

    Energy Technology Data Exchange (ETDEWEB)

    Borel, H; Grenier, P; Le Meur, J; Lombard, R; Lugol, J C; Marroncle, J; Morgenstern, J; Mouly, J P; Paul, B; Staley, F; Terrien, Y [CEA Centre d` Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d` Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l` Instrumentation Associee; Breton, V; Comptour, C; Crouau, M; Fonvieille, H; Roblin, Y; Savinel, G [Clermont-Ferrand-2 Univ., 63 - Aubiere (France); Gearhart, R [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1994-10-01

    The two electromagnetic calorimeters each made of 200 lead glass blocks used at SLAC to discriminate between electrons and pions and to measure electron energies are described. Procedures to reconstruct electron showers and to calibrate calorimeters are treated as well as the calorimeter performance. (author). 6 refs., 10 figs.

  19. The design of a semi-custom intergrated circuit for the SLAC SLC timing control system

    International Nuclear Information System (INIS)

    Linstadt, E.

    1985-01-01

    A semi-custom (gate array) integrated circuit has been designed for use in the SLAC Linear Collider timing and control system. The design process and SLAC's experiences during the phases of the design cycle are described. Issues concerning the partitioning of the design into semi-custom and standard components are discussed. Functional descriptions of the semi-custom integrated circuit and the timing module in which it is used are given

  20. Integrated management tool for controls software problems, requests and project tasking at SLAC

    International Nuclear Information System (INIS)

    Rogind, D.; Allen, W.; Colocho, W.; DeContreras, G.; Gordon, J.; Pandey, P.; Shoaee, H.

    2012-01-01

    The Accelerator Directorate (AD) Instrumentation and Controls (ICD) Software (SW) Department at SLAC, with its service center model, continuously receives engineering requests to design, build and support controls for accelerator systems lab-wide. Each customer request can vary in complexity from a small software engineering change to a major enhancement. SLAC's Accelerator Improvement Projects (AIPs), along with DOE Construction projects, also contribute heavily to the work load. The various customer requests and projects, paired with the ongoing operational maintenance and problem reports, place a demand on the department that consistently exceeds the capacity of available resources. A centralized repository - comprised of all requests, project tasks, and problems - available to physicists, operators, managers, and engineers alike, is essential to capture, communicate, prioritize, assign, schedule, track, and finally, commission all work components. The Software Department has recently integrated request / project tasking into SLAC's custom online problem tracking 'Comprehensive Accelerator Tool for Enhancing Reliability' (CATER) tool. This paper discusses the newly implemented software request management tool - the workload it helps to track, its structure, features, reports, work-flow and its many usages. (authors)

  1. SLAC linear collider: the machine, the physics, and the future

    International Nuclear Information System (INIS)

    Richter, B.

    1981-11-01

    The SLAC linear collider, in which beams of electrons and positrons are accelerated simultaneously, is described. Specifications of the proposed system are given, with calculated preditions of performance. New areas of research made possible by energies in the TeV range are discussed

  2. Linear and nonlinear optical properties of a hydrogenic donor in lens-shaped quantum dots

    International Nuclear Information System (INIS)

    Vahdani, M.R.K.; Rezaei, G.

    2009-01-01

    Optical transitions in a Lens-Shaped Quantum Dot (LSD) are investigated in the presence of a hydrogenic impurity. The electronic wave functions are obtained analytically and the energy eigenvalues are calculated numerically. The density matrix formulation with the intersubband relaxation are used to evaluate the (linear and third order nonlinear) absorption coefficient (AC) and the change in the refractive indices (RI) analytically. The effect of the size of the LSD and optical intensity on the AC and RI are investigated. It is found that AC and RI are strongly affected by the optical intensity and the size of the LSD.

  3. Linear and nonlinear optical properties of a hydrogenic donor in lens-shaped quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Vahdani, M.R.K. [Department of Physics, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Rezaei, G., E-mail: grezaei@mail.yu.ac.i [Department of Physics, College of Sciences, Yasouj University, Yasouj 75914 (Iran, Islamic Republic of)

    2009-08-17

    Optical transitions in a Lens-Shaped Quantum Dot (LSD) are investigated in the presence of a hydrogenic impurity. The electronic wave functions are obtained analytically and the energy eigenvalues are calculated numerically. The density matrix formulation with the intersubband relaxation are used to evaluate the (linear and third order nonlinear) absorption coefficient (AC) and the change in the refractive indices (RI) analytically. The effect of the size of the LSD and optical intensity on the AC and RI are investigated. It is found that AC and RI are strongly affected by the optical intensity and the size of the LSD.

  4. Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Weathersby, S. P.; Brown, G.; Chase, T. F.; Coffee, R.; Corbett, J.; Eichner, J. P.; Frisch, J. C.; Fry, A. R.; Gühr, M.; Hartmann, N.; Hast, C.; Hettel, R.; Jobe, R. K.; Jongewaard, E. N.; Lewandowski, J. R.; Li, R. K., E-mail: lrk@slac.stanford.edu; Lindenberg, A. M.; Makasyuk, I.; May, J. E.; McCormick, D. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); and others

    2015-07-15

    Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

  5. Binary rf pulse compression experiment at SLAC

    International Nuclear Information System (INIS)

    Lavine, T.L.; Spalek, G.; Farkas, Z.D.; Menegat, A.; Miller, R.H.; Nantista, C.; Wilson, P.B.

    1990-06-01

    Using rf pulse compression it will be possible to boost the 50- to 100-MW output expected from high-power microwave tubes operating in the 10- to 20-GHz frequency range, to the 300- to 1000-MW level required by the next generation of high-gradient linacs for linear for linear colliders. A high-power X-band three-stage binary rf pulse compressor has been implemented and operated at the Stanford Linear Accelerator Center (SLAC). In each of three successive stages, the rf pulse-length is compressed by half, and the peak power is approximately doubled. The experimental results presented here have been obtained at low-power (1-kW) and high-power (15-MW) input levels in initial testing with a TWT and a klystron. Rf pulses initially 770 nsec long have been compressed to 60 nsec. Peak power gains of 1.8 per stage, and 5.5 for three stages, have been measured. This corresponds to a peak power compression efficiency of about 90% per stage, or about 70% for three stages, consistent with the individual component losses. The principle of operation of a binary pulse compressor (BPC) is described in detail elsewhere. We recently have implemented and operated at SLAC a high-power (high-vacuum) three-stage X-band BPC. First results from the high-power three-stage BPC experiment are reported here

  6. ''ARBOLA'' SLAC branch driver for PDP-11

    International Nuclear Information System (INIS)

    Oxoby, G.

    1976-08-01

    The wide use of CAMAC systems in the Large Aperture Solenoid Spectrometer facility led to the design of several dedicated CAMAC interfaces. The one described here features the implementation of bidirectional data transfers, and is used exclusively with the SLAC crate controller, 135-279. Efforts were made to ensure maximum versatility for acquisition of high-energy physics data. Specifications are set forth, and hardware and software (memory address register, word count register, data buffer register, and high-byte register) are described. 4 figures

  7. STANFORD (SLAC): B factory construction begins

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1994-03-15

    At a ceremony marking the start of construction, members of the US Congress and Secretary of Energy Hazel O'Leary hailed the new Asymmetric B Factory as the key to continued vitality of the Stanford Linear Accelerator Center (SLAC). Being built in collaboration with the Lawrence Berkeley Laboratory and the Lawrence Livermore National Laboratory, the B factory is a $177 million upgrade of the existing PEP electron-positron collider. Scheduled for completion in 1998, the B factory will generate many millions of B mesons, allowing, among other physics, an intensive search for the phenomena of CP violation in the decays of these particles.

  8. Nanosecond electron beam generation and instrumentation at SLAC

    International Nuclear Information System (INIS)

    Koontz, R.F.; Miller, R.H.

    1975-01-01

    The present SLAC injector system, including the latest beam chopping equipment, is discussed, and an updated diagram is given. The present equipment can produce almost any mix of chopped and single bunch beams for experimenters with a high degree of multiple beam compatibility. Topics covered include the grid pulsers, the pulse isolation transformers, the resonant choppers, the nonresonant chopper, the synchronization system, and the fast beam monitors. (PMA)

  9. The status of the SLAC Linear Collider and of the Mark II detector

    International Nuclear Information System (INIS)

    Lankford, A.J.

    1987-10-01

    At SLAC we are currently involved in the exciting challenge of commissioning the first example of a new type of colliding beam accelerator, the SLAC Linear Collider, or SLC. The goals of the SLC are two-fold. It will explore the concept of linear colliders, and it will allow the study of physics on the Z 0 resonance. It accomplishes these goals by exploiting the existing SLAC linac and the large visible cross-section of approximately thirty nanobarns of the Z 0 . The MARK II detector will have the opportunity to be first to explore the physics in this regime. This paper briefly reports the status of the SLC and of the MARK II as of early October 1987, at which time commissioning efforts were interrupted in order to place the MARK II detector at the collision point and to incorporate some improvements to the SLC. The first portion of this report highlights some of the milestones achieved in the SLC commissioning and some of the problems encountered. The last portion outlines improvements made to the MARK II for physics at the SLC. 10 refs., 12 figs., 1 tab

  10. The UCLA/SLAC Ultra-High Gradient Cerenkov Wakefield Accelerator Experiment

    CERN Document Server

    Thompson, Matthew C; Hogan, Mark; Ischebeck, Rasmus; Muggli, Patric; Rosenzweig, James E; Scott, A; Siemann, Robert; Travish, Gil; Walz, Dieter; Yoder, Rodney

    2005-01-01

    An experiment is planned to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range. This new UCLA/SLAC collaboration will take advantage of the unique SLAC FFTB electron beam and its demonstrated ultra-short pulse lengths and high currents (e.g., sz = 20 μm at Q = 3 nC). The electron beam will be focused down and sent through varying lengths of fused silica capillary tubing with two different sizes: ID = 200 μm / OD = 325 μm and ID = 100 μm / OD = 325 μm. The pulse length of the electron beam will be varied in order to alter the accelerating gradient and probe the breakdown threshold of the dielectric structures. In addition to breakdown studies, we plan to collect and measure coherent Cerenkov radiation emitted from the capillary tube to gain information about the strength of the accelerating fields. Status and progress on the experiment are reported.

  11. Protection of the eye lens

    International Nuclear Information System (INIS)

    2015-01-01

    The limit of radiation exposure for eye lens is going to decrease dramatically from 150 to 20 mSv as a transposition into the French law of a CIPR (International Commission for Radiation Protection) directive. Sanitary studies have shown that radiologists are more likely by a factor of 3.8 to get eye lens opacities than the rest of the population. The wearing of protective glasses is recommended and in order to get a better monitoring of the radiation dose new dosimeters have been designed, they can be worn on the glass frame of directly stuck on the skin near the eyes. A study has shown that veterinary surgeons that are accustomed to stay near animals to keep them quiet during radiological exams are prone to receive high doses as well as physicians that use hypnosis to decrease the level of anxiety of their patients during radiological exams. Radiation exposure of radiologists can be mitigated through: the use of protective shields and equipment and the optimization of the dose delivered to the patient. (A.C.)

  12. STANFORD (SLAC): B factory construction begins

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    At a ceremony marking the start of construction, members of the US Congress and Secretary of Energy Hazel O'Leary hailed the new Asymmetric B Factory as the key to continued vitality of the Stanford Linear Accelerator Center (SLAC). Being built in collaboration with the Lawrence Berkeley Laboratory and the Lawrence Livermore National Laboratory, the B factory is a $177 million upgrade of the existing PEP electron-positron collider. Scheduled for completion in 1998, the B factory will generate many millions of B mesons, allowing, among other physics, an intensive search for the phenomena of CP violation in the decays of these particles

  13. Two microcomputer-controller applications at SLAC

    International Nuclear Information System (INIS)

    Struven, W.C.; Mallory, K.B.

    1977-03-01

    The SLAC Accelerator Control and Monitoring System, as originally implemented, was a manual (non-computer) control system with provisions to add computers at a later date. Since operation began in 1966, a PDP9 with a PDP8/e ''front end'' was added in the accelerator control room, and most recently, eight PDP8/f's were added in the two mile Klystron Gallery which are linked to the 8/e front end. A data link was added between the PDP9 and an SDS 925 in the Main Control Room. Tough panel interfaces were provided so that the Accelerator and Beam Switchyard could be controlled and monitored from one console

  14. A 2--4 nm Linac Coherent Light Source (LCLS) using the SLAC linac

    International Nuclear Information System (INIS)

    Winick, H.; Bane, K.; Boyce, R.

    1993-05-01

    We describe the use of the SLAC linac to drive a unique, powerful. short wavelength Linac Coherent Light Source (LCLS). Operating as an FEL, lasing would be achieved in a single pass of a high peak current electron beam through a long undulator by self-amplified spontaneous emission (SASE). The main components are a high-brightness rf photocathode electron gun; pulse compressors; about 1/5 of the SLAC linac; and a long undulator with a FODO quadrupole focussing system. Using electrons below 8 GeV, the system would operate at wavelengths down to about 3 nm, producing ≥10 GW peak power in sub-ps pulses. At a 120 Hz rate the average power is ∼ 1 W

  15. dE/dx electronics for MARK II experiment at SLAC

    International Nuclear Information System (INIS)

    Bernstein, D.; Boyarski, A.; Coupal, D.; Feldman, G.; Paffrath, L.

    1985-10-01

    This paper describes a 100 MHz pulse digitizer for dE/dx measurements on the MARK II drift chamber at SLAC. The electronics provides the read-out of the detector's 5832 sense based on a 16-channel FASTBUS module. The basic element of the module is the TRW 6-bit Flash-ADC

  16. Status of the SLAC SNOOP diagnostic module for FASTBUS

    International Nuclear Information System (INIS)

    Walz, H.V.; Gustavson, D.B.

    1983-03-01

    A SNOOP Diagnostic Module for FASTBUS is under development at SLAC. The SNOOP Module resides on a FASTBUS crate segment and provides diagnostic monitoring and testing capability. It consists of a high-speed ECL front-end to monitor and single-step segment operations, a simple master interface, and a control processor with two serial communication ports. Module features and specifications are summrized, and prototype hardware is shown

  17. Linear collider research and development at SLAC, LBL and LLNL

    International Nuclear Information System (INIS)

    Mattison, T.S.

    1988-10-01

    The study of electron-positron (e + e/sup /minus//) annihilation in storage ring colliders has been very fruitful. It is by now well understood that the optimized cost and size of e + e/sup /minus// storage rings scales as E(sub cm//sup 2/ due to the need to replace energy lost to synchrotron radiation in the ring bending magnets. Linear colliders, using the beams from linear accelerators, evade this scaling law. The study of e/sup +/e/sup /minus// collisions at TeV energy will require linear colliders. The luminosity requirements for a TeV linear collider are set by the physics. Advanced accelerator research and development at SLAC is focused toward a TeV Linear Collider (TLC) of 0.5--1 TeV in the center of mass, with a luminosity of 10/sup 33/--10/sup 34/. The goal is a design for two linacs of less than 3 km each, and requiring less than 100 MW of power each. With a 1 km final focus, the TLC could be fit on Stanford University land (although not entirely within the present SLAC site). The emphasis is on technologies feasible for a proposal to be framed in 1992. Linear collider development work is progressing on three fronts: delivering electrical energy to a beam, delivering a focused high quality beam, and system optimization. Sources of high peak microwave radio frequency (RF) power to drive the high gradient linacs are being developed in collaboration with Lawrence Berkeley Laboratory (LBL) and Lawrence Livermore National Laboratory (LLNL). Beam generation, beam dynamics and final focus work has been done at SLAC and in collaboration with KEK. Both the accelerator physics and the utilization of TeV linear colliders were topics at the 1988 Snowmass Summer Study. 14 refs., 4 figs., 1 tab

  18. Single lens to lens duplication: The missing link

    OpenAIRE

    Bhatt, Rupal; Jethani, Jitendra; Saluja, Praveen; Bharti, Vinay

    2008-01-01

    Congenital anomalies of the lens include a wide range from lens coloboma to primary aphakia and doubling of lens. There have been few case reports of double lens; the etiology suggested is metaplastic changes in the surface ectoderm that leads to formation of two lens vesicles and hence resulting in double lens. We report a case with bilobed lens, which raises the possibility of explaining the etiology of double lens.

  19. Results of the SLAC LCLS Gun High-Power RF Tests

    International Nuclear Information System (INIS)

    Dowell, D.H.; Jongewaard, E.; Limborg-Deprey, C.; Schmerge, J.F.; Li, Z.; Xiao, L.; Wang, J.; Lewandowski, J.; Vlieks, A.

    2007-01-01

    The beam quality and operational requirements for the Linac Coherent Light Source (LCLS) currently being constructed at SLAC are exceptional, requiring the design of a new RF photocathode gun for the electron source. Based on operational experience at SLAC's GTF and SDL and ATF at BNL as well as other laboratories, the 1.6cell s-band (2856MHz) gun was chosen to be the best electron source for the LCLS, however a significant redesign was necessary to achieve the challenging parameters. Detailed 3-D analysis and design was used to produce near-perfect rotationally symmetric rf fields to achieve the emittance requirement. In addition, the thermo-mechanical design allows the gun to operate at 120Hz and a 140MV/m cathode field, or to an average power dissipation of 4kW. Both average and pulsed heating issues are addressed in the LCLS gun design. The first LCLS gun is now fabricated and has been operated with high-power RF. The results of these high-power tests are presented and discussed

  20. An Automated 476 MHz RF Cavity Processing Facility at SLAC

    CERN Document Server

    McIntosh, P; Schwarz, H

    2003-01-01

    The 476 MHz accelerating cavities currently used at SLAC are those installed on the PEP-II B-Factory collider accelerator. They are designed to operate at a maximum accelerating voltage of 1 MV and are routinely utilized on PEP-II at voltages up to 750 kV. During the summer of 2003, SPEAR3 will undergo a substantial upgrade, part of which will be to replace the existing 358.54 MHz RF system with essentially a PEP-II high energy ring (HER) RF station operating at 476.3 MHz and 3.2 MV (or 800 kV/cavity). Prior to installation, cavity RF processing is required to prepare them for use. A dedicated high power test facility is employed at SLAC to provide the capability of conditioning each cavity up to the required accelerating voltage. An automated LabVIEW based interface controls and monitors various cavity and test stand parameters, increasing the RF fields accordingly such that stable operation is finally achieved. This paper describes the high power RF cavity processing facility, highlighting the features of t...

  1. Gallium arsenide digital integrated circuits for controlling SLAC CW-RF systems

    International Nuclear Information System (INIS)

    Ronan, M.T.; Lee, K.L.; Corredoura, P.; Judkins, J.G.

    1989-01-01

    In order to fill the PEP and SPEAR storage rings with beams from the SLC linac and damping rings, precise control of the linac subharmonic buncher and the damping ring RF is required. Recently several companies have developed resettable GaAs master/slave D-type flip-flops which are capable of operating at frequencies of 3 GHz and higher. Using these digital devices as frequency dividers, one can phase shift the SLAC CW-RF systems to optimize the timing for filling the storage rings. The authors have evaluated the performance of integrated circuits from two vendors for our particular application. Using microstrip circuit techniques, they have built and operated in the accelerator several chassis to synchronize a reset signal from the storage rings to the SLAC 2.856 GHz RF and to phase shift divide-by-four and divide-by-sixteen frequency dividers to the nearest 350 psec bucket required for filling

  2. Gallium arsenide digital integrated circuits for controlling SLAC CW-RF systems

    International Nuclear Information System (INIS)

    Ronan, M.T.; Lee, K.L.; Corredoura, P.; Judkins, J.G.

    1988-10-01

    In order to fill the PEP and SPEAR storage rings with beams from the SLC linac and damping rings, precise control of the linac subharmonic buncher and the damping ring RF is required. Recently several companies have developed resettable GaAs master/slave D-type flip-flops which are capable of operating at frequencies of 3 GHz and higher. Using these digital devices as frequency dividers, one can phase shift the SLAC CW-RF systems to optimize the timing for filling the storage rings. We have evaluated the performance of integrated circuits from two vendors for our particular application. Using microstrip circuit techniques, we have built and operated in the accelerator several chassis to synchronize a reset signal from the storage rings to the SLAC 2.856 GHz RF and to phase shift divide-by-four and divide-by-sixteen frequency dividers to the nearest 350 psec bucket required for filling. 4 refs., 4 figs., 2 tabs

  3. Physics at the SLC [SLAC Linear Collider

    International Nuclear Information System (INIS)

    Swartz, M.L.

    1990-11-01

    The SLAC Linear Collider (SLC) was constructed in the years 1983--1987 for two principal reasons: to develop the accelerator physics and technology that are necessary for the construction of future linear electron-positron colliders; and to produce electron-positron collisions at the Z 0 pole and to study the physics of the weak neutral current. To date, the SLC program has been quite successful at achieving the first goal. The machine has produced and collided high energy electron and positron beams of three-micron transverse size. The problems of operating an open geometry detector in an environment that is more akin to those found in fixed-target experiments than in storage rings have largely been solved. As a physics producing venture, the SLC has been less successful than was originally hoped but more successful than is commonly believed. Some of the results that have been produced by the Mark II experiment with a very modest data sample are competitive with those that have been produced with much larger samples by the four LEP collaborations. At the current, time, SLAC is engaged in an ambitious program to upgrade the SLC luminosity and to exploit one of its unique features, a spin polarized electron beam. These lectures are therefore organized into three sections: a brief description of the SLC; a review of the physics results that have been achieved with the Mark II detector; a description of the SLC's future: the realization and use of a polarized electron beam

  4. Proceedings of the SLC workshop on experimental use of the SLAC Linear Collider

    International Nuclear Information System (INIS)

    1982-03-01

    In March 1981, the SLAC management, together with the SLAC users organization, invited interested physicists to a three day meeting to discuss the laboratory's plans and progress on the new colliding e + e - machine - the Stanford Linear Collider (SLC). Those attending were encouraged to join together to study the challenges and opportunities presented by the SLC. The study of the parameters for experiments on 100 GeV e + e - collisions, and the reviews of the state-of-the-art in the four areas of detector technology - Tracking, Calorimetry, Particle Identification and Electronics and Computing - were undertaken from a general standpoint, and not from the particular perspective of a specific experimental proposal. Nine sections were prepared separately for the data base

  5. Radiation Dose Measurement for High-Intensity Laser Interactions with Solid Targets at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Taiee [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-09-25

    A systematic study of photon and neutron radiation doses generated in high-intensity laser-solid interactions is underway at SLAC National Accelerator Laboratory. We found that these laser-solid experiments are being performed using a 25 TW (up to 1 J in 40 fs) femtosecond pulsed Ti:sapphire laser at the Linac Coherent Light Source’s (LCLS) Matter in Extreme Conditions (MEC) facility. Additionally, radiation measurements were performed with passive and active detectors deployed at various locations inside and outside the target chamber. Results from radiation dose measurements for laser-solid experiments at SLAC MEC in 2014 with peak intensity between 1018 to 7.1x1019 W/cm2 are presented.

  6. Pulsed rf superconductivity program at SLAC

    International Nuclear Information System (INIS)

    Campisi, I.E.; Farkas, Z.D.

    1984-08-01

    Recent tests performed at SLAC on superconducting TM 010 caavities using short rf pulses (less than or equal to 2.5 μs) have established that at the cavity surface magnetic fields can be reached in the vicinity of the theoretical critical fields without an appreciable increase in average losses. Tests on niobium and lead cavities are reported. The pulse method seems to be best suited to study peak field properties of superconductors in the microwave band, without the limitations imposed by defects. The short pulses also seem to be more effective in decreasing the causes of field emission by rf processing. Applications of the pulsed rf superconductivity to high-gradient linear accelerators are also possible

  7. Microprocessors in physics experiments at SLAC

    International Nuclear Information System (INIS)

    Rochester, L.S.

    1981-01-01

    The increasing size and complexity of high energy physics experiments is changing the way data are collected. To implement a trigger or event filter requires complex logic which may have to be modified as the experiment proceeds. Simply to monitor a detector, large amounts of data must be processed online. The use of microprocessors or other programmable devices can help to achieve these ends flexibly and economically. At SLAC, a number of microprocessor-based systems have been built and are in use in experimental setups, and others are now being developed. This talk is a review of existing systems and their use in experiments, and of developments in progress and future plans. (orig.)

  8. Microprocessors in physics experiments at SLAC

    International Nuclear Information System (INIS)

    Rochester, L.S.

    1981-04-01

    The increasing size and complexity of high energy physics experiments is changing the way data are collected. To implement a trigger or event filter requires complex logic which may have to be modified as the experiment proceeds. Simply to monitor a detector, large amounts of data must be processed on line. The use of microprocessors or other programmable devices can help to achieve these ends flexibly and economically. At SLAC, a number of microprocessor-based systems have been built and are in use in experimental setups, and others are now being developed. This talk is a review of existing systems and their use in experiments, and of developments in progress and future plans

  9. PEP radiation shielding tests in SLAC A Beam

    International Nuclear Information System (INIS)

    Ash, W.; DeStaebler, H.; Harris, J.; Jenkins, T.; Murray, J.

    1977-09-01

    Radiation shielding tests designed to simulate possible conditions in and around the PEP experimental halls were conducted. The SLAC A Beam was targeted in the block tunnel at a point about midway between End Station A and Beam Dump East. At that site it was relatively easy to rearrange the concrete block structure to simulate the various shielding configurations under consideration for PEP. Extensive surveys of neutron and ionizing radiation were made. Complete results of the shielding tests are given

  10. Development of operator requested control system applications: Experience with the SLC control system at SLAC

    International Nuclear Information System (INIS)

    Stanek, M.

    1995-01-01

    The SLC Control system at SLAC has evolved into a powerful tool for operation of the accelerator and for troubleshooting the unique problems encountered in extracting maximum performance from the SLC. The evolution has included the development of many custom applications and user interface features generated from accelerator operator and accelerator physicist requests. These applications are written and maintained primarily by the Controls Software Engineering group, and not by the users themselves. The process of developing and supporting user requested control systems applications at SLAC is described, including the effects of organizational structure, formal and informal procedures, and control system architecture

  11. BABAR - the detector for the PEP II B Factory at SLAC

    International Nuclear Information System (INIS)

    Lueth, V.

    1994-09-01

    BABAR refers to the detector that is being designed for the PEP II B-Factory at SLAC to perform a comprehensive study of CP violation in B meson decays. The design requirements and the principal detector components are briefly described. A summary of the expected physics performance is presented

  12. Neutron dosimetry at SLAC: Neutron sources and instrumentation

    International Nuclear Information System (INIS)

    Liu, J.C.; Jenkins, T.M.; McCall, R.C.; Ipe, N.E.

    1991-10-01

    This report summarizes in detail the dosimetric characteristics of the five radioisotopic type neutron sources ( 238 PuBe, 252 Cf, 238 PuB, 238 PuF 4 , and 238 PuLi) and the neutron instrumentation (moderated BF 3 detector, Anderson-Braun (AB) detector, AB remmeter, Victoreen 488 Neutron Survey Meter, Beam Shut-Off Ionization Chamber, 12 C plastic scintillator detector, moderated indium foil detector, and moderated and bare TLDs) that are commonly used for neutron dosimetry at the Stanford Linear Accelerator Center (SLAC). 36 refs,. 19 figs

  13. Beam-beam studies for the proposed SLAC/LBL/LLNL B Factory

    International Nuclear Information System (INIS)

    Furman, M.A.

    1991-05-01

    We present a summary of beam-beam dynamics studies that have been carried out to date for the proposed SLAC/LBL/LLNL B Factory. Most of the material presented here is contained in the proposal's Conceptual Design Report, although post-CDR studies are also presented. 15 refs., 6 figs., 2 tabs

  14. Aberration design of zoom lens systems using thick lens modules.

    Science.gov (United States)

    Zhang, Jinkai; Chen, Xiaobo; Xi, Juntong; Wu, Zhuoqi

    2014-12-20

    A systematic approach for the aberration design of a zoom lens system using a thick lens module is presented. Each component is treated as a thick lens module at the beginning of the design. A thick lens module refers to a thick lens component with a real lens structure, like lens materials, lens curvatures, lens thicknesses, and lens interval distances. All nine third-order aberrations of a thick lens component are considered during the design. The relationship of component aberrations in different zoom positions can be approximated from the aberration shift. After minimizing the aberrations of the zoom lens system, the nine third-order aberrations of every lens component can be determined. Then the thick lens structure of every lens component can be determined after optimization according to their first-order properties and third-order aberration targets. After a third optimization for minimum practical third-order aberrations of a zoom lens system, the aberration design using the thick lens module is complete, which provides a practical zoom lens system with thick lens structures. A double-sided telecentric zoom lens system is designed using the thick lens module in this paper, which shows that this method is practical for zoom lens design.

  15. Single bunch beam loading on the SLAC three-kilometer accelerator

    International Nuclear Information System (INIS)

    Koontz, R.F.; Loew, G.A.; Miller, R.H.; Wilson, P.B.

    1977-03-01

    Since the report on single bunch beam loading experiments at SLAC at the 1975 Particle Accelerator Conference, it has been possible to obtain a much better understanding and agreement of theoretical and experimental results related to this problem. These improvements were made possible by two developments: the generation of a ''wake-field'' function for the SLAC 3-km slow-wave structure and the use of this function to calculate single bunch energy spectra. The wake-field function which gives the time decay of the fields generated by the passage of a delta-function beam was derived by summing all the TM cylindrically symmetrical modes of an equivalent accelerator cavity. By multiplying this wake-field function by a measured bunch density function and integrating along the bunch, it is possible to calculate the energy of each electron in the bunch. This in turn enables one to predict the energy spectrum for any given phase angle of the bunch with respect to the crest of the rf accelerating wave. Agreement between these calculations and experimental measurements is very good. These results are presented, and the possible sources of some of the remaining discrepancies are discussed

  16. Single bunch beam loading on the SLAC three-kilometer accelerator

    International Nuclear Information System (INIS)

    Koontz, R.F.; Loew, G.A.; Miller, R.H.; Wilson, P.B.

    1977-01-01

    Since the report on single bunch beam loading experiments at SLAC at the 1975 Particle Accelerator Conference, it has been possible to obtain a much better understanding and agreement of theoretical and experimental results related to this problem. These improvements have been made possible by two developments: the generation of a ''wake-field'' function for the SLAC 3-km slow-wave structure and the use of this function to calculate single bunch energy spectra. The wake-field function which gives the time decay of the fields generated by the passage of a delta-function beam was derived by summing all the TM cylindrically symmetrical modes of an equivalent accelerator cavity. By multiplying this wake-field function by a measured bunch density function and integrating along the bunch, it is possible to calculate the energy of each electron in the bunch. This in turn enables one to predict the energy spectrum for any given phase angle of the bunch with respect to the crest of the rf accelerating wave. Agreement between these calculations and experimental measurements is very good. These results are presented and the possible sources of some of the remaining discrepancies are discussed

  17. Neutron dosimetry at SLAC: Neutron sources and instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J.C.; Jenkins, T.M.; McCall, R.C.; Ipe, N.E.

    1991-10-01

    This report summarizes in detail the dosimetric characteristics of the five radioisotopic type neutron sources ({sup 238}PuBe, {sup 252}Cf, {sup 238}PuB, {sup 238}PuF{sub 4}, and {sup 238}PuLi) and the neutron instrumentation (moderated BF{sub 3} detector, Anderson-Braun (AB) detector, AB remmeter, Victoreen 488 Neutron Survey Meter, Beam Shut-Off Ionization Chamber, {sup 12}C plastic scintillator detector, moderated indium foil detector, and moderated and bare TLDs) that are commonly used for neutron dosimetry at the Stanford Linear Accelerator Center (SLAC). 36 refs,. 19 figs.

  18. SLAC to host symposium celebrating 10th anniversary of first website in America

    CERN Multimedia

    2001-01-01

    Many of the programmers, web designers and scientists who collaborated to create the world wide web will be in SLAC for a two-day symposium to celebrate the 10th anniversary of the first website in America.

  19. Operating experience with the polarized electron gun at SLAC

    International Nuclear Information System (INIS)

    Alguard, M.J.; Baum, G.; Clendenin, J.E.; Hughes, V.W.; Lubell, M.S.; Miller, R.H.; Raith, W.; Schuler, K.P.; Sodja, J.

    1977-03-01

    During the two years of operation of the SLAC Polarized Electron Gun (PEGGY), the electron intensity delivered to the target has increased from 7 x 10 7 e - /pulse to 1 x 10 9 e - /pulse. The polarization is 0.85 with no measurable degradation caused by acceleration through the linear accelerator. The predominant cause of downtime is replenishment of lithium, which now averages 43 hours. The lifetime of a lithium load is about 175 hours

  20. Parameters of the SLAC Next Linear Collider

    International Nuclear Information System (INIS)

    Raubenheimer, T.; Adolphsen, C.; Burke, D.

    1995-05-01

    In this paper, the authors present the parameters and layout of the Next Linear Collider (NLC). The NLC is the SLAC design of a future linear collider using X-band RF technology in the main linacs. The collider would have an initial center-of-mass energy of 0.5 TeV which would be upgraded to 1 TeV and then 1.5 TeV in two stages. The design luminosity is > 5 x 10 33 cm -2 sec -1 at 0.5 TeV and > 10 34 cm -2 sec -1 at 1.0 and 1.5 TeV. They briefly describe the components of the collider and the proposed energy upgrade scenario

  1. Performance of the SLAC Linear Collider klystrons

    International Nuclear Information System (INIS)

    Allen, M.A.; Fowkes, W.R.; Koontz, R.F.; Schwarz, H.D.; Seeman, J.T.; Vlieks, A.E.

    1987-01-01

    There are now 200 new, high power 5045 klystrons installed on the two-mile Stanford Linear Accelerator. Peak power per klystron averages over 63 MW. Average energy contribution is above 240 MeV per station. Electron beam energy has been measured as high as 53 GeV. Energy instability due to kylstron malfunction is less than 0.2%. The installed klystrons have logged over one million operating hours with close to 20,00 klystron hours cumulative operating time between failures. Data is being accumulated on klystron operation and failure modes with failure signatures starting to become apparent. To date, no wholesale failure modes have surfaced that would impair the SLAC linear Collider (SLC) program

  2. Cerenkov ring imaging detector development at SLAC

    International Nuclear Information System (INIS)

    Williams, S.H.

    1984-06-01

    The imaging of Cerenkov light on to photosensitive detectors promises to be a powerful technique for identifying particles in colliding beam spectrometers. Toward this end two and three dimensional imaging photon detectors are being developed at SLAC. The present techniques involve photon conversion using easily ionized exotic chemicals like tetrakisdimethyl-amino-ethylene (TMAE) in a drift and amplifying gas mixture of methane and isobutane. Single photoelectrons from Cerenkov light are currently being drifted 20 cm and a new device under study will be used to study drifting up to 80 cm along a magnetic field. A short description of a large device currently being designed for the SLD spectrometer at the Stanford Linear Collider will be given

  3. Searching for light dark matter with the SLAC millicharge experiment.

    Science.gov (United States)

    Diamond, M; Schuster, P

    2013-11-27

    New sub-GeV gauge forces ("dark photons") that kinetically mix with the photon provide a promising scenario for MeV-GeV dark matter and are the subject of a program of searches at fixed-target and collider facilities around the world. In such models, dark photons produced in collisions may decay invisibly into dark-matter states, thereby evading current searches. We reexamine results of the SLAC mQ electron beam dump experiment designed to search for millicharged particles and find that it was strongly sensitive to any secondary beam of dark matter produced by electron-nucleus collisions in the target. The constraints are competitive for dark photon masses in the ~1-30 MeV range, covering part of the parameter space that can reconcile the apparent (g-2)(μ) anomaly. Simple adjustments to the original SLAC search for millicharges may extend sensitivity to cover a sizable portion of the remaining (g-2)(μ) anomaly-motivated region. The mQ sensitivity is therefore complementary to ongoing searches for visible decays of dark photons. Compared to existing direct-detection searches, mQ sensitivity to electron-dark-matter scattering cross sections is more than an order of magnitude better for a significant range of masses and couplings in simple models.

  4. Reconstitution of CO2 Regulation of SLAC1 Anion Channel and Function of CO2-Permeable PIP2;1 Aquaporin as CARBONIC ANHYDRASE4 Interactor

    Science.gov (United States)

    Zeise, Brian; Xu, Danyun; Rappel, Wouter-Jan; Boron, Walter F.; Schroeder, Julian I.

    2016-01-01

    Dark respiration causes an increase in leaf CO2 concentration (Ci), and the continuing increases in atmospheric [CO2] further increases Ci. Elevated leaf CO2 concentration causes stomatal pores to close. Here, we demonstrate that high intracellular CO2/HCO3− enhances currents mediated by the Arabidopsis thaliana guard cell S-type anion channel SLAC1 upon coexpression of any one of the Arabidopsis protein kinases OST1, CPK6, or CPK23 in Xenopus laevis oocytes. Split-ubiquitin screening identified the PIP2;1 aquaporin as an interactor of the βCA4 carbonic anhydrase, which was confirmed in split luciferase, bimolecular fluorescence complementation, and coimmunoprecipitation experiments. PIP2;1 exhibited CO2 permeability. Mutation of PIP2;1 in planta alone was insufficient to impair CO2- and abscisic acid-induced stomatal closing, likely due to redundancy. Interestingly, coexpression of βCA4 and PIP2;1 with OST1-SLAC1 or CPK6/23-SLAC1 in oocytes enabled extracellular CO2 enhancement of SLAC1 anion channel activity. An inactive PIP2;1 point mutation was identified that abrogated water and CO2 permeability and extracellular CO2 regulation of SLAC1 activity. These findings identify the CO2-permeable PIP2;1 as key interactor of βCA4 and demonstrate functional reconstitution of extracellular CO2 signaling to ion channel regulation upon coexpression of PIP2;1, βCA4, SLAC1, and protein kinases. These data further implicate SLAC1 as a bicarbonate-responsive protein contributing to CO2 regulation of S-type anion channels. PMID:26764375

  5. [Pigment dispersion and Artisan implants: crystalline lens rise as a safety criterion].

    Science.gov (United States)

    Baikoff, G; Bourgeon, G; Jodai, H Jitsuo; Fontaine, A; Vieira Lellis, F; Trinquet, L

    2005-06-01

    To validate the theoretical notion of a crystalline lens rise as a safety criterion for ARTISAN implants in order to prevent the development of pigment dispersion in the implanted eye. Crystalline lens rise is defined by the distance between the crystalline lens's anterior pole and the horizontal plane joining the opposite iridocorneal recesses. We analyzed the biometric measurements of 87 eyes with an Artisan implant. A comparative analysis of the crystalline lens rise was carried out on the nine eyes having developed pigment dispersion and 78 eyes with no problems. Among the modern anterior segment imaging devices (Artemis, Scheimpflug photography, optical coherence tomography, radiology exploration, magnetic resonance imaging, TDM), an anterior chamber optical coherence tomography (AC-OCT) prototype was used. This working hypothesis was confirmed by this study: the crystalline lens rise must be considered as a new safety criterion for implanting Artisan phakic lenses. Indeed, the higher the crystalline lens's rise, the greater the risk of developing pigment dispersion in the pupil area. This complication is more frequent in hyperopes than in myopes. We can consider that there is little or no risk of pigment dispersion if the rise is below 600 microm; however, at 600 microm or greater, there is a 67% rate of pupillary pigment dispersion. In certain cases, when the implant was loosely fixed, there was no traction on the iris root. This is a complication that can be avoided or delayed. The crystalline lens rise must be part of new safety criteria to be taken into consideration when inserting an Artisan implant. This notion must also be applied to other types of phakic implants. The distance remaining between the crystalline lens rise and a 600-micromm theoretical safety level allows one to calculate a safety time interval.

  6. Pigment dispersion and Artisan phakic intraocular lenses: crystalline lens rise as a safety criterion.

    Science.gov (United States)

    Baïkoff, Georges; Bourgeon, Grégoire; Jodai, Horacio Jitsuo; Fontaine, Aline; Lellis, Fernando Viera; Trinquet, Laure

    2005-04-01

    To validate the theory that crystalline lens rise can be used as a safety criterion to prevent pigment dispersion in eyes with an Artisan phakic intraocular lens (IOL) (Ophtec BV). Monticelli Clinic, Marseilles, France. A comparative analysis of crystalline lens rise in 9 eyes with pigment dispersion and 78 eyes without dispersion was performed. All eyes had previous implantation of an Artisan IOL. Anterior segment imaging was done using an anterior chamber optical coherence tomography (AC OCT) prototype. Crystalline lens rise was defined by the distance between the anterior pole of the crystalline lens and the horizontal plane joining the opposite iridocorneal recesses. The study confirmed that crystalline lens rise can be considered a safety criterion for implantation of Artisan-type phakic IOLs. The higher the crystalline lens rise, the greater the risk for developing pigment dispersion in the area of the pupil. This complication occurred more frequently in hyperopic eyes than in myopic eyes. Results indicate there is little or no risk for pigment dispersion if the rise is less than 600 microm; 67% of eyes with a rise of 600 microm or more developed pupillary pigment dispersion. In some cases in which the IOL was loosely fixated, there was no traction on the iris root and dispersion was prevented or delayed. Crystalline lens rise should be considered a new safety criterion for Artisan phakic IOL implantation and should also be applied to other types of phakic IOLs. The distance remaining between the crystalline lens rise and a 600 microm theoretical safety level allows one to calculate how long the IOL can safely remain in the eye.

  7. Compliance of SLAC's Laser Safety Program with OSHA Requirements for the Control of Hazardous Energy

    International Nuclear Information System (INIS)

    Woods, M.

    2009-01-01

    SLAC's COHE program requires compliance with OSHA Regulation 29CFR1910.147, 'The control of hazardous energy (lockout/tagout)'. This regulation specifies lockout/tagout requirements during service and maintenance of equipment in which the unexpected energization or start up of the equipment, or release of stored energy, could cause injury to workers. Class 3B and Class 4 laser radiation must be considered as hazardous energy (as well as electrical energy in associated equipment, and other non-beam energy hazards) in laser facilities, and therefore requires careful COHE consideration. This paper describes how COHE is achieved at SLAC to protect workers against unexpected Class 3B or Class 4 laser radiation, independent of whether the mode of operation is normal, service, or maintenance

  8. Final Report: BaBar Detector and Experimental at SLAC, September 30, 1998 - September 29, 1999

    International Nuclear Information System (INIS)

    Judd, Dennis J.

    2000-01-01

    The Prairie View AandM University High Energy Physics Group with its contingent of three undergraduates physics majors, joined the BaBar Collaboration at SLAC in September 1994. BaBar is the experiment and detector running in the PEP-II ring at SLAC as part of the Asymmetric B Factory project there to study CP violation and heavy flavor physics. The focus of our effort before this year was with the Muon/Neutral Hadron Detector/Instrumented Flux Return (IFD) subgroup within the BaBar collaboration, and particularly with the GEANT simulation of the IFR-. With the GEANT3 simulation essentially FR-ozen, and the GEANT4 full simulation of the IFR- done, we have decided to redirect our efforts toward other areas

  9. Final Report BaBar Detector and Experimental at SLAC, September 30, 1998 - September 29, 1999

    CERN Document Server

    Judd, D J

    2000-01-01

    The Prairie View AandM University High Energy Physics Group with its contingent of three undergraduates physics majors, joined the BaBar Collaboration at SLAC in September 1994. BaBar is the experiment and detector running in the PEP-II ring at SLAC as part of the Asymmetric B Factory project there to study CP violation and heavy flavor physics. The focus of our effort before this year was with the Muon/Neutral Hadron Detector/Instrumented Flux Return (IFD) subgroup within the BaBar collaboration, and particularly with the GEANT simulation of the IFR-. With the GEANT3 simulation essentially FR-ozen, and the GEANT4 full simulation of the IFR- done, we have decided to redirect our efforts toward other areas.

  10. Lens stem cells may reside outside the lens capsule: an hypothesis

    Directory of Open Access Journals (Sweden)

    Meyer Rita A

    2007-06-01

    Full Text Available Abstract In this paper, we consider the ocular lens in the context of contemporary developments in biological ideas. We attempt to reconcile lens biology with stem cell concepts and a dearth of lens tumors. Historically, the lens has been viewed as a closed system, in which cells at the periphery of the lens epithelium differentiate into fiber cells. Theoretical considerations led us to question whether the intracapsular lens is indeed self-contained. Since stem cells generate tumors and the lens does not naturally develop tumors, we reasoned that lens stem cells may not be present within the capsule. We hypothesize that lens stem cells reside outside the lens capsule, in the nearby ciliary body. Our ideas challenge the existing lens biology paradigm. We begin our discussion with lens background information, in order to describe our lens stem cell hypothesis in the context of published data. Then we present the ciliary body as a possible source for lens stem cells, and conclude by comparing the ocular lens with the corneal epithelium.

  11. SLC status and SLAC future plans

    International Nuclear Information System (INIS)

    Richter, B.

    1990-01-01

    In this presentation, I shall discuss the linear collider program at the Stanford Linear Accelerator Center as it is now, and as we hope to see it evolve over the next few years. Of greatest interest to the high-energy accelerator physics community gathered here is the development of the linear collider concept, and so I shall concentrate most of this paper on a discussion of the present status and future evolution of the SLC. I will also briefly discuss the research and development program that we are carrying out aimed at the realization of the next generation of higher-energy linear colliders. SLAC has a major colliding-beam storage-ring program as well, including present rings and design studies on future high luminosity projects, but time constraints preclude a discussion of them. (author) 8 figs., 3 tabs

  12. Measurements of the Z boson resonance parameters at SLC [SLAC Linear Collider

    International Nuclear Information System (INIS)

    Hearty, C.

    1989-07-01

    This paper presents the measurement by the Mark II experiment at the SLAC Linear Collider of the parameters of the Z boson resonance. The results are updated from those presented at the SLAC Summer Institute to include all data presented in the most recent Mark II publication, consisting of 19 nb -1 of data at ten different center-of-mass energies between 89.2 and 93.0 GeV. The resonance parameters are extracted by measuring the Z production cross section at a series of center-of-mass energies (scan points) near the Z peak, then fitting these data with the theoretical cross section. The four major aspects of the analysis are the determination at each scan point of the center-of-mass energy (E), the integrated luminosity, the number of Z decays and the expected cross section as a function of the resonance parameters, such as mass and width. I will discuss each of these steps in turn, after a brief description of the Mark II detector, then conclude with the results of the analysis. 7 refs., 9 figs., 3 tabs

  13. Measurements of ultimate accelerating gradients in the SLAC disk-loaded structure. Part I

    International Nuclear Information System (INIS)

    Wang, J.W.; Loew, G.A.

    1985-01-01

    The work reported here describes measurements made to study the maximum attainable accelerating gradients in a conventional SLAC disk-loaded accelerator section of the constant-gradient type running at 2856 MHz. The objective was to reach an accelerating gradient of at least 100 MV/m. The accelerating gradient at which the SLAC disk-loaded waveguide runs routinely is approx. 9 MV/m (36 MW tubes without SLED) and approx. 12 MV/m with SLED I (2.5 μsec pulse). To reach 100 MV/m in a conventional 3 m constant-gradient section, one would need a klystron with a peak power output of 900 MW. since such a tube is not available, we decided to use a short standing-wave section in which the resonant fields would be allowed to build up. The design criteria for this section, the fabrication, matching and tuning, the experimental set-up and the results are described below

  14. SLAC divertor channel entrance thermal stress analysis

    International Nuclear Information System (INIS)

    Johnson, G.L.; Stein, W.; Lu, S.C.; Riddle, R.A.

    1985-01-01

    X-ray beams emerging from the new SLAC electron-positron storage ring (PEP) impinge on the entrance to tangential divertor channels causing highly localized heating in the channel structure. Analyses were completed to determine the temperatures and thermally-induced stresses due to this heating. These parts are cooled with water flowing axially over them at 30 0 C. The current design and operating conditions should result in the entrance to the new divertor channel operating at a peak temperature of 123 0 C with a peak thermal stress at 91% of yield. Any micro-cracks that form due to thermally-induced stresses should not propagate to the coolant wall nor form a path for the coolant to leak into the storage ring vacuum. 34 figs., 4 tabs

  15. Using the SLAC VHF and UHF radio systems

    International Nuclear Information System (INIS)

    Struven, W.

    1987-02-01

    The use of the SLAC VHF and UHF Radio Systems and the Tunnel Antenna Systems as they are presently configured is described. The original radio system was built in 1966 and has grown in scope over the years. The Tunnel Antenna Systems were developed for, and first installed in, the PEP ring, and later added to other tunnels and redesigned to cover the UHF range, as well as VHF. The UHF radio system was designed and built for SLC use, and was first used in the SLC Arcs. The three radio systems will be described and the capabilities of each system will be defined

  16. An S-type anion channel SLAC1 is involved in cryptogein-induced ion fluxes and modulates hypersensitive responses in tobacco BY-2 cells.

    Science.gov (United States)

    Kurusu, Takamitsu; Saito, Katsunori; Horikoshi, Sonoko; Hanamata, Shigeru; Negi, Juntaro; Yagi, Chikako; Kitahata, Nobutaka; Iba, Koh; Kuchitsu, Kazuyuki

    2013-01-01

    Pharmacological evidence suggests that anion channel-mediated plasma membrane anion effluxes are crucial in early defense signaling to induce immune responses and hypersensitive cell death in plants. However, their molecular bases and regulation remain largely unknown. We overexpressed Arabidopsis SLAC1, an S-type anion channel involved in stomatal closure, in cultured tobacco BY-2 cells and analyzed the effect on cryptogein-induced defense responses including fluxes of Cl(-) and other ions, production of reactive oxygen species (ROS), gene expression and hypersensitive responses. The SLAC1-GFP fusion protein was localized at the plasma membrane in BY-2 cells. Overexpression of SLAC1 enhanced cryptogein-induced Cl(-) efflux and extracellular alkalinization as well as rapid/transient and slow/prolonged phases of NADPH oxidase-mediated ROS production, which was suppressed by an anion channel inhibitor, DIDS. The overexpressor also showed enhanced sensitivity to cryptogein to induce downstream immune responses, including the induction of defense marker genes and the hypersensitive cell death. These results suggest that SLAC1 expressed in BY-2 cells mediates cryptogein-induced plasma membrane Cl(-) efflux to positively modulate the elicitor-triggered activation of other ion fluxes, ROS as well as a wide range of defense signaling pathways. These findings shed light on the possible involvement of the SLAC/SLAH family anion channels in cryptogein signaling to trigger the plasma membrane ion channel cascade in the plant defense signal transduction network.

  17. Accelerator structure bead pull measurement at SLAC

    CERN Document Server

    Lewandowski, J R; Miller, R H; Wang, J W

    2004-01-01

    Microwave measurement and tuning of accelerator structures are important issues for the current and next generation of high energy physics machines. Application of these measurements both before and after high power processing can reveal information about the structure but may be misinterpreted if measurement conditions are not carefully controlled. For this reason extensive studies to characterize the microwave measurements at have been made at SLAC. For the beadpull a reproducible measurement of less than 1 degree of phase accuracy in total phase drift is needed in order to resolve issues such as phase changes due to structure damage during high power testing. Factors contributing to measurement errors include temperature drift, mechanical vibration, and limitations of measurement equipment such as the network analyzer. Results of this continuing effort will be presented.

  18. SLAC linear collider and a few ideas on future linear colliders

    International Nuclear Information System (INIS)

    Loew, G.A.

    1984-04-01

    This paper comes in two parts. The first part is a progress report on the SLAC Linear Collider (SLC) with emphasis on those systems which are of special interest to linear accelerator designers; it sets the stage for a number of contributed papers on specific topics which are also presented at this conference. The second part presents some ideas which are of interest to the design of future linear colliders of higher energies

  19. Electron Bunch Length Measurement for LCLS at SLAC

    International Nuclear Information System (INIS)

    Zelazny, M.; Allison, S.; Chevtsov, Sergei; Emma, P.; Kotturi, K.d.; Loos, H.; Peng, S.; Rogind, D.; Straumann, T.

    2007-01-01

    At Stanford Linear Accelerator Center (SLAC) a Bunch Length Measurement system has been developed to measure the length of the electron bunch for its new Linac Coherent Light Source (LCLS). This destructive measurement uses a transverse-mounted RF deflector (TCAV) to vertically streak the electron beam and an image taken with an insertable screen and a camera. The device control software was implemented with the Experimental Physics and Industrial Control System (EPICS) toolkit. The analysis software was implemented in Matlab(trademark) using the EPICS/Channel Access Interface for Scilab(trademark) and Matlab(trademark) (labCA). This architecture allowed engineers and physicists to develop and integrate their control and analysis without duplication of effort

  20. Commissioning and operation of the nuclear physics injector at SLAC

    International Nuclear Information System (INIS)

    Koontz, R.F.; Iverson, R.; Leyer, G.K.; Miller, R.H.

    1985-01-01

    The new Nuclear Physics Injector (NPI) approved for construction in October of 1983 was completed by September of 1984, and delivered short pulse beams for SPEAR ring checkout in mid-October. Long pulse beams of up to 1.6 microsecond length were also demonstrated. The paper describes the startup operation, reviews the performance characteristics, and discusses the beam transport optics used to deliver 1 to 4 GeV beams to nuclear physics experiments in End Station A. The SLAC Nuclear Physics Injector is in full operationexclamation

  1. Commissioning and operation of the nuclear physics injector at SLAC

    International Nuclear Information System (INIS)

    Koontz, R.F.; Miller, R.H.; Leger, G.K.; Iverson, R.

    1985-01-01

    The new Nuclear Physics Injector (NPI) approved for construction in October of 1983 was completed by September of 1984, and delivered short pulse beams for SPEAR ring checkout in mid-October. Long pulse beams of up to 1.6 microsecond length were also demonstrated. The paper describes the start-up operation, reviews the performance characteristics, and discusses the beam transport optics used to deliver 1 to 4 GeV beams to nuclear physics experiments in End Station A. The SLAC Nuclear Physics Injector is in full operation!

  2. A Correlation of Thin Lens Approximation to Thick Lens Design by Using Coddington Factors in Lens Design and Manufacturing

    OpenAIRE

    FARSAKOĞLU, Ö. Faruk

    2014-01-01

    The effect of Coddington factors on aberration functions has been analysed using thin lens approximation. Minimizing spherical aberrations of singlet lenses using Coddington factors in lens design depending on lens manufacturing is discussed. Notation of lens test plate pairs used in lens manufacturing is also presented in terms of Coddington shape factors.

  3. Gas system Upgrade for the BaBar IFR Detector at SLAC

    International Nuclear Information System (INIS)

    Foulkes, S

    2004-01-01

    A new gas distribution and monitoring system was installed as part of an upgrade of the forward endcap muon detection system (IFR) of the BaBar detector at SLAC. Over 300 gas circuits are controlled and monitored. The return gas flow is monitored by digital bubblers which use photo-gate electronics to count the bubbling rate. The rates are monitored in real time and recorded in a history database allowing studies of flow rate versus chamber performance

  4. SLAC/SPIRES Announces the Top-Cited Papers of 2000

    International Nuclear Information System (INIS)

    O'Connell, Heath B

    2002-01-01

    Physicists who search the literature on elementary particles know that the SLAC library's SPIRES-HEP database provides an essential tool. The database lists virtually every paper published or even preprinted in high energy physics over the past thirty years. The database connects preprint or eprint versions to articles published in journals or conference proceedings, providing access to all phases of the publication history. In addition, most papers have backward links to the papers they cite and forward links to the papers citing them. These citation linkages provide a very effective means of searching the literature on any topic of interest. In the past few years, SPIRES-HEP has been automatically harvesting reference citations from eprints, creating a web of links which indexes the literature in a quite thorough manner. As a byproduct of this citation linkage, SPIRES-HEP can easily search out the papers most highly cited by publications in high-energy physics. The list of papers with the most citations in a given year provides a snapshot of the hottest topics that have engaged the attention of theorists and experimenters. For the past several years, SPIRES-HEP has posted a scientific review of the year's top-cited papers. The whole collection of these reviews can be found on the Web at: http://www.slac.stanford.edu/library/topcites/. We have recently posted the topcite lists for the year 2000. These materials include a list of the papers with more than 100 citations in the past year, and a list of the paper with more than 1000 citations over the history of the SPIRES-HEP database

  5. Immunohistochemical studies of lens crystallins in the dysgenetic lens (dyl) mutant mice

    NARCIS (Netherlands)

    Brahma, S.K.; Sanyal, S.

    1984-01-01

    The lens in the dyl mutant mice shows a persistent lens-ectodermal connection as well as degeneration and extrusion of lens materials after the initial differentiation of the fibres. Immunohistochemical investigation of the ontogeny of the lens crystallins in this developing mutant lens has been

  6. Status of the SLAC/LBL/LLNL B-factory and the BABAR detector

    International Nuclear Information System (INIS)

    Oddone, P.

    1994-10-01

    After a brief introduction on the physics reach of the SLAC/LBL/LLNL Asymmetric B-Factory, the author describes the status of the accelerator and the detector as of the end of 1994. At this time, essentially all major decisions have been made, including the choice of particle identification for the detector. The author concludes this report with the description of the schedule for the construction of both accelerator and detector

  7. The development of the Next Linear Collider at SLAC

    International Nuclear Information System (INIS)

    Ruth, R.D.

    1992-02-01

    At SLAC, we are pursuing the design of a Next Linear Collider (NLC) which would begin with a center-of-mass energy of 0.5 TeV and be upgradable to at least 1.0 TeV, and possibly 1.5 TeV. The luminosity is designed to be 10 33 cm -2 s -1 at the lower energy and 10 34 cm -2 s -1 at the top energy. In this paper, we discuss the accelerator physics issues which are important in our approach, and also the present state of the technology development. We also review the impact that the SLC has had in the evolution of our basic approach

  8. Sharing of secondary electrons by in-lens and out-lens detector in low-voltage scanning electron microscope equipped with immersion lens.

    Science.gov (United States)

    Kumagai, Kazuhiro; Sekiguchi, Takashi

    2009-03-01

    To understand secondary electron (SE) image formation with in-lens and out-lens detector in low-voltage scanning electron microscopy (LV-SEM), we have evaluated SE signals of an in-lens and an out-lens detector in LV-SEM. From the energy distribution spectra of SEs with various boosting voltages of the immersion lens system, we revealed that the electrostatic field of the immersion lens mainly collects electrons with energy lower than 40eV, acting as a low-pass filter. This effect is also observed as a contrast change in LV-SEM images taken by in-lens and out-lens detectors.

  9. Laser Safety for the Experimental Halls at SLAC_s Linac Coherent Light Source (LCLS)

    Energy Technology Data Exchange (ETDEWEB)

    Woods, Michael; Anthony, Perry; /SLAC; Barat, Ken; /LBL, Berkeley; Gilevich, Sasha; Hays, Greg; White, William E.; /SLAC

    2009-01-15

    The LCLS at the SLAC National Accelerator Laboratory will be the world's first source of an intense hard x-ray laser beam, generating x-rays with wavelengths of 1nm and pulse durations less than 100fs. The ultrafast x-ray pulses will be used in pump-probe experiments to take stop-motion pictures of atoms and molecules in motion, with pulses powerful enough to take diffraction images of single molecules, enabling scientists to elucidate fundamental processes of chemistry and biology. Ultrafast conventional lasers will be used as the pump. In 2009, LCLS will deliver beam to the Atomic Molecular and Optical (AMO) Experiment, located in one of 3 x-ray Hutches in the Near Experimental Hall (NEH). The NEH includes a centralized Laser Hall, containing up to three Class 4 laser systems, three x-ray Hutches for experiments and vacuum transport tubes for delivering laser beams to the Hutches. The main components of the NEH laser systems are a Ti:sapphire oscillator, a regen amplifier, green pump lasers for the oscillator and regen, a pulse compressor and a harmonics conversion unit. Laser safety considerations and controls for the ultrafast laser beams, multiple laser controlled areas, and user facility issues are discussed.

  10. Annual Site Environmental Report Prepared for the Department of Energy,under contract number DE-AC03-76SF00515 January - December 2001

    International Nuclear Information System (INIS)

    Russak, Hillary M.

    2003-01-01

    This report provides information about environmental programs during 2001 at the Stanford Linear Accelerator Center (SLAC). Also included are seasonal activities that cross calendar-year divisions. Production of the annual site environmental report (ASER) is a requirement established by the US Department of Energy (DOE) for all management and operating (M and O) contractors throughout the DOE complex. SLAC is federally-funded, research development center with Stanford University as the M and O contractor. The most noteworthy information in this report is summarized in this section. This summary demonstrates the effective application of SLAC environmental management in meeting the site's Integrated Safety Management System (ISMS) goals. For normal daily activities, all SLAC managers and supervisors are responsible for ensuring that proper procedures are followed to meet the ISMS goals: Worker safety and health are protected; The environment is protected; and Compliance is assured. Throughout 2001, SLAC focused on these activities through the SLAC management systems. These systems were also the ways SLAC approached implementing the ''Greening of the Government'' initiatives (such as Executive Order 13148). The management systems at SLAC are effective, supporting compliance with all relevant statutory and regulatory requirements. SLAC did not receive any notices of violation during 2001. In addition, many improvements were continued during 2001, including improvements in the storm drain system, improved ground water monitoring capabilities, and enhancements to the system to manage the generation of mixed wastes. Environmental program-specific summary details are shown below

  11. Annual Site Environmental Report Prepared for the Department of Energy,under contract number DE-AC03-76SF00515 January - December 2001

    Energy Technology Data Exchange (ETDEWEB)

    Russak, Hillary M.

    2003-05-06

    This report provides information about environmental programs during 2001 at the Stanford Linear Accelerator Center (SLAC). Also included are seasonal activities that cross calendar-year divisions. Production of the annual site environmental report (ASER) is a requirement established by the US Department of Energy (DOE) for all management and operating (M&O) contractors throughout the DOE complex. SLAC is federally-funded, research development center with Stanford University as the M and O contractor. The most noteworthy information in this report is summarized in this section. This summary demonstrates the effective application of SLAC environmental management in meeting the site's Integrated Safety Management System (ISMS) goals. For normal daily activities, all SLAC managers and supervisors are responsible for ensuring that proper procedures are followed to meet the ISMS goals: Worker safety and health are protected; The environment is protected; and Compliance is assured. Throughout 2001, SLAC focused on these activities through the SLAC management systems. These systems were also the ways SLAC approached implementing the ''Greening of the Government'' initiatives (such as Executive Order 13148). The management systems at SLAC are effective, supporting compliance with all relevant statutory and regulatory requirements. SLAC did not receive any notices of violation during 2001. In addition, many improvements were continued during 2001, including improvements in the storm drain system, improved ground water monitoring capabilities, and enhancements to the system to manage the generation of mixed wastes. Environmental program-specific summary details are shown below.

  12. Search milli-charged particles at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Langeveld, W.G.J. [Stanford Univ., CA (United States)

    1997-01-01

    Particles with electric charge q {triple_bond} Qe {le} 10{sup -3} e and masses in the range 1-1000 MeV/c{sup 2} are not excluded by present experiments or by astrophysical or cosmological arguments. A beam dump experiment uniquely suited to the detection of such {open_quotes}milli-charged{close_quotes} particles has been carried out at SLAC, utilizing the short-duration pulses of the SLC electron beam to establish a tight coincidence window for the signal. The detector, a large scintillation counter sensitive to very small energy depositions, provided much greater sensitivity than previous searches. Analysis of the data leads to the exclusion of a substantial portion of the charge-mass plane. In this report, a preliminary mass-dependent upper limit is presented for the charge of milli-charged particles, ranging from Q = 1.7 x 10{sup -5} at milli-charged particle mass 0.1 MeV/c{sup 2} to Q = 9.5 x 10{sup -4} at 100 MeV/c{sup 2}.

  13. Wide-band cable systems at SLAC

    International Nuclear Information System (INIS)

    Struven, W.

    1983-01-01

    SLAC's first cable TV system was installed in 1979 to remotely monitor a narrow pulse which was generated in the west end of the klystron gallery. When Stanford Linear Collider (SLC) experimental work started at the west end of the accelerator, the original 1979 cable was upgraded to a bidirectional system so that 2 MBaud point-to-point data and several video and 9600 baud channels could be transmitted. The implementation of the SLC requires a complete upgrading of the accelerator control system. The system is based on a distributed processing configuration using a PDP11/780 VAX in the Main Control Center (MCC) and Intel single-board computers in a multibus configuration along the accelerator. The high-speed data linking is supplied by a 1 MBaud Time Division Multiple Access (TDMA) Network. The same cable is used to provide video, low-speed data, voice and high-speed point-to-point data services. The transmission system will utilize a wideband midsplit cable facility to collect and distribute signals to all parts of the network

  14. Requirements for use of nonmedical x-ray generators at SLAC

    International Nuclear Information System (INIS)

    Busick, D.D.

    1984-09-01

    The risks associated with use of x-ray equipment have long been recognized. While the relative frequency of x-ray damage is small, machine produced x-rays and large radiography sources continue to account for a large percentage of preventable radiation injuries reported worldwide. The intent of this report is to formalize SLAC's radiation safety program as it applies to radiation producing equipment (diffraction, fluorescence analysis and nondestructive testing). It does not apply to the two-mile linac, experimental areas or other x-ray producing equipment directly related to the high energy physics program. 4 refs., 3 figs., 1 tab

  15. SLAC modulator operation and reliability in the SLC Era

    International Nuclear Information System (INIS)

    Donaldson, A.R.; Ashton, J.R.

    1992-06-01

    A discussion of the operation and reliability of the 244 modulators in the SLAC linac with an emphasis on the past three years of operation. The linac modulators were designed and built in the 60's, upgraded for the SLAC Linear Collider (SLC) in the mid 80s, and despite their age are still reliable accelerator components. The 60s modulator operated at 65 MW peak and 83 kW average power. The upgrade resulted in 150 MW peak output at an average power of 87 kW, a modest increase since the repetition rate was dropped from 360 to 120 Hz. In the present accelerator configuration, the Linac operates as a source of electrons and positrons to a single pass coillider. The classic collider is a storage ring filled with oppositely charged, counter-rotating particles which are allowed to collide until an accelerator fault occurs and the stored beams are aborted. A reasonable storage ring can store and collide particles for as long as eight hours with a 10 or 20 minute filling time. A single pass collider, + on the other hand, can only produce e - and e + collisions at whatever rate the source operates. To be effective the SLC must operate at 120 Hz with a very high degree of reliability and on a continuous basis. Fortunately, the linac has a modest excess of modulator/klystron systems which allows some measure of redundancy and hence some freedom from the constraint that all 244 modulator/klystrons operate simultaneously. Nonetheless, high importance is placed on modulator MTBF and MTRR or, in the parlance of reliability experts and accelerator physicists, availability. This is especially true of the modulators associated with the fundamental requirements of a collider such as injection, compression and positron production

  16. A Strong-Lens Survey in AEGIS: the influence of large scalestructure

    Energy Technology Data Exchange (ETDEWEB)

    Moustakas, Leonidas A.; Marshall, Phil; Newman, Jeffrey A.; Coil,Alison L.; Cooper, Michael C.; Davis, Marc; Fassnacht, Christopher D.; Guhathakurta, Puragra; Hopkins, Andrew; Koekemoer, Anton; Konidaris,Nicholas P.; Lotz, Jennifer M.; Willmer, Christopher N. A.

    2006-10-13

    We report on the results of a visual search for galaxy-scale strong gravitational lenses over 650 arcmin{sup 2} of HST/ACS (F606W and F814W) imaging in the DEEP2-Extended Groth Strip (EGS). In addition to a previously-known Einstein Cross also found by our search (the 'Cross', HSTJ141735+52264, z{sub lens} = 0.8106, z{sub source} = 3.40), we identify two new strong galaxy-galaxy lenses with multiple extended arcs. The first, HSTJ141820+52361 (the 'Dewdrop'; z{sub lens} = 0.5798), lenses two distinct extended sources into two pairs of arcs (z{sub source} = 0.9818), while the second, HSTJ141833+52435 (the 'Anchor'; z{sub lens} = 0.4625), produces a single pair of arcs (z{sub lens} not yet known). Four less convincing arc/counter-arc and two-image lens candidates are also found and presented for completeness. Lenses are found in a both underdense and overdense local environments, as characterized by a robust measure, 1+{delta}{sub 3}, a normalized density that uses the distance to the third nearest neighbor. All three definite lenses are fit reasonably well by simple singular isothermal ellipsoid models including external shear, giving {chi}{sub {nu}}{sup 2} values close to unity. These shears are much greater than those implied by a simple consideration of the three-dimensional convergence and shear from galaxies along the line of sight, where each galaxy is approximated by a singular isothermal sphere halo truncated at 200 h{sup -1} kpc. This shows how a realistic treatment of galaxies and the large scale structure they are embedded in is necessary, and that simply characterizing the very-local environment may be insufficient.

  17. High gradient tests of SLAC Linear Collider Accelerator Structures

    International Nuclear Information System (INIS)

    Wang, J.W.; Deruyter, H.; Eichner, J.; Fant, K.H.; Hoag, H.A.; Koontz, R.F.; Lavine, T.; Loew, G.A.; Loewen, R.; Menegat, L.

    1994-08-01

    This paper describes the current SLAC R ampersand D program to develop room temperature accelerator structures for the Next Linear Collider (NLC). The structures are designed to operate at 11.4 GHz at an accelerating gradient in the range of 50 to 100 MV/m. In the past year a 26 cm constant-impedance traveling-wave section, a 75 cm constant-impedance traveling-wave section, and a 1.8 m traveling-wave section with detuned deflecting modes have been high-power tested. The paper presents a brief description of the RF test setup, the design and manufacturing details of the structures, and a discussion of test results including field emission, RF processing, dark current spectrum and RF breakdown

  18. Production of high intensity electron bunches for the SLAC Linear Collider

    International Nuclear Information System (INIS)

    James, M.B.

    1987-08-01

    This thesis describes the design and performance of a high intensity electron injecfor for the SLAC Linear Collider. Motivation for the collider and the specifications for the injector are discussed. An analytic theory of the bunching and capture of electrons by rf fields is discussed in the limit of low space charge and small signal. The design and performance of SLAC's main injector are described to illustrate a successful application of this theory. The bunching and capture of electrons by rf fields are then discussed in the limit of high space charge and large signal, and a description of the design of the collider injector follows. In the limit of high space charge forces and large rf signals, the beam dynamics are considerably more complex and numerical simulations are required to predict particle motion. A computer code which models the longitudinal dynamics of electrons in the presence of space charge and rf fields is described. The results of the simulations, the resulting collider injector design and the various components which make up the collider injector are described. These include the gun, subharmonic bunchers, traveling-wave buncher and velocity-of-light accelerator section. Finally, the performance of the injector is described including the beam intensity, bunch length, transverse emittance and energy spectrum. While the final operating conditions differ somewaht from the design, the performance of the collider injector is in good agreement with the numerical simulations and meets all of the collider specifications. 28 refs

  19. Post-lens tear turbidity and visual quality after scleral lens wear.

    Science.gov (United States)

    Carracedo, Gonzalo; Serramito-Blanco, Maria; Martin-Gil, Alba; Wang, Zicheng; Rodriguez-Pomar, Candela; Pintor, Jesús

    2017-11-01

    The aim was to evaluate the turbidity and thickness of the post-lens tear layer and its effect on visual quality in patients with keratoconus after the beginning of lens wear and before lens removal at the end of eight hours. Twenty-six patients with keratoconus (aged 36.95 ± 8.95 years) participated voluntarily in the study. The sample was divided into two groups: patients with intrastromal corneal ring (ICRS group) and patients without ICRS (KC group). Distance visual acuity (VA), contrast sensitivity, pachymetry, post-lens tear layer height and post-lens tear layer turbidity (percentage area occupied and number of particles per mm 2 ) were evaluated with optical coherence tomography before and after wearing a scleral lens. A significant increase of turbidity was found in all groups assessed (p turbidity parameters with distance VA but no correlation between turbidity and post-lens tear layer thickness at the beginning was found (p > 0.05). A strong correlation in all groups between the post-lens tear layer at the beginning and differences of tear layer thickness between two measures was also found (p turbidity. © 2017 Optometry Australia.

  20. Disinfection capacity of PuriLens contact lens cleaning unit against Acanthamoeba.

    Science.gov (United States)

    Hwang, Thomas S; Hyon, Joon Young; Song, Jae Kyung; Reviglio, Victor E; Spahr, Harry T; O'Brien, Terrence P

    2004-01-01

    The PuriLens contact lens system is indicated for cleaning and disinfection of soft (hydrophilic) contact lenses by means of subsonic agitation to remove lens deposits and microorganisms, and ultraviolet irradiation of the storage solution for disinfection. The capacity of the PuriLens system to disinfect storage solutions contaminated with known concentrations of Staphylococcus aureus, Pseudomonas aeruginosa, and Acanthamoeba species was evaluated. An in vitro assessment of the antibacterial and antiparasitic efficacy of the PuriLens system was performed. Separated batches of the storage solution for the cleansing system were contaminated with stock strains of S. aureus and P. aeruginosa. A comparison of the microbiologic content was made between the solution before and after the cycle. The PuriLens system effectively eradicated S. aureus and P. aeruginosa organisms after a 15-minute cycle. However, viable cysts of acanthamoeba were recovered in the solution after the 15-minute cycle. The PuriLens system is highly efficient in protecting against contamination with common bacterial ocular pathogens. Acanthamoeba cysts, however, can survive in the solution or contact lens bath undergoing integrated subsonic debridement and indirect ultraviolet light disinfection. Use of chemical disinfecting solutions that contain agents such as chlorhexidine or other cationic antiseptics may be advisable in conjunction with use of the PuriLens device, especially in high-risk settings.

  1. The Effect of the Crystalline Lens on Central Vault After Implantable Collamer Lens Implantation.

    Science.gov (United States)

    Qi, Meng-Ying; Chen, Qian; Zeng, Qing-Yan

    2017-08-01

    To identify associations between crystalline lens-related factors and central vault after Implantable Collamer Lens (ICL) (Staar Surgical, Monrovia, CA) implantation. This retrospective clinical study included 320 eyes from 186 patients who underwent ICL implantation surgery. At 1 year after surgery, the central vault was measured using anterior segment optical coherence tomography. Preoperative anterior chamber depth, lens thickness, lens position (lens position = anterior chamber depth + 1/2 lens thickness), and vault were analyzed to investigate the effects of lens-related factors on postoperative vault. The mean vault was 513 ± 215 µm at 1 year after surgery. Vault was positively correlated with preoperative anterior chamber depth (r = 0.495, P lens position (r = 0.371, P lens thickness (r = -0.262, P lens position than eyes in the other two vault groups (which had vaults ≥ 250 µm) (P lens position less than 5.1 mm had greatly reduced vaults (P lens could have an important influence on postoperative vault. Eyes with a shallower anterior chamber and a forward lens position will have lower vaults. [J Refract Surg. 2017;33(8):519-523.]. Copyright 2017, SLACK Incorporated.

  2. Parton distributions from SMC and SLAC data

    International Nuclear Information System (INIS)

    Ramsey, G.P.

    1996-01-01

    We have extracted spin-weighted parton distributions in a proton from recent data at CERN and SLAC. The valence, sea quark and Antiquark spin-weighted distributions are determined separately. The data are all consistent with a small to moderate polarized gluon distribution, so that the anomaly term is not significant in the determination of the constituent contributions to the spin of the proton. We have analyzed the consistency of the results obtained from various sets of data and the Biorken sum rule. Although all data are consistent with the sum rule, the polarized distributions from different experiments vary, even with higher order QCD corrections taken into account. Results split into two models, one set implying a large polarized strange sea which violates the positivity bound, and the other set yielding a smaller polarized strange sea. Only further experiments which extract information about the polarized sea will reconcile these differences. We suggest specific experiments which can be performed to determine the size of the polarized sea and gluons

  3. Personnel dose equivalent monitoring at SLAC using lithium-fluoride TLD's [thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Jenkins, T.M.; Busick, D.D.

    1987-03-01

    TLD's replaced film badges in the early 1970's for all dose equivalent monitoring, both neutron and photon, and for all locations at SLAC. The photon TLD's, composed of Li-7 loaded teflon discs, are calibrated using conventional gamma-ray sources; i.e., Co-60, Cs-137, etc. For these TLD's a nominal value of 1 nC/mrem is used, and is independent of source energy for 100 keV to 3 MeV. Since measured dose equivalents at SLAC are only a small fraction of the allowable levels, it was not deemed necessary to develop neutron dosimeters which would measure dose equivalent accurately for all possible neutron spectra. Today, wallet TLD's, composed of pairs of Li-7 and Li-6 discs, are used, with the Li-6 measuring only thermal neutrons; i.e., they aren't moderated in any way to make them sensitive to neutrons with energies greater than thermal. The assumption is made that there is a correlation between thermal neutron fluences and fast neutron fluences around the research area where almost all neutron doses (exclusive of sealed sources) are received. The calibration factor for these Li-6 TLD's is 1 nC/mrem of fast neutrons. The method of determining the validity of this calibration is the subject of this note. 4 refs., 9 figs., 1 tab

  4. FEL research and development at the SLAC sub-picosecond photon source, SPPS

    International Nuclear Information System (INIS)

    Bentson, L.; Bolton, P.; Bong, E.; Emma, P.; Galayda, J.; Hastings, J.; Krejcik, P.; Rago, C.; Rifkin, J.; Spencer, C.M.

    2003-01-01

    An upgrade project to the SLAC linac allows ultra-short electron bunches to be interleaved with the routine high-energy physics program operation, for use with an undulator to produce short-pulse, high-brightness X-rays. The linac upgrade comprises of the installation in the summer of 2002 of a bunch compressor chicane of similar design to the Linac Coherent Light Source (LCLS) project. A final compression stage in the high-energy Final Focus Test Beam (FFTB) line compresses the 28 GeV, 3.4 nC electron bunch to 80 fs FWHM, where a 5 m section of undulator (K=4.45) will produce 1.5 A X-rays with 3x10 7 photons per pulse and a peak brightness of 4x10 24 photons mm -2 mrad -2 s -1 (0.1% BW). The facility will allow us to test the dynamics and associated technology of bunch compression and gain valuable experience for the LCLS using the SLAC linac. New ultra-short electron bunch diagnostic techniques will be developed hand in hand with the same ultra-fast laser technology to be used for LCLS. Issues of high peak power (27 GW) X-ray transport and optics can be addressed at this facility as well as pump-probe and ultra-fast laser timing and stability issues

  5. Measurement of Crystalline Lens Volume During Accommodation in a Lens Stretcher.

    Science.gov (United States)

    Marussich, Lauren; Manns, Fabrice; Nankivil, Derek; Maceo Heilman, Bianca; Yao, Yue; Arrieta-Quintero, Esdras; Ho, Arthur; Augusteyn, Robert; Parel, Jean-Marie

    2015-07-01

    To determine if the lens volume changes during accommodation. The study used data acquired on 36 cynomolgus monkey lenses that were stretched in a stepwise fashion to simulate disaccommodation. At each step, stretching force and dioptric power were measured and a cross-sectional image of the lens was acquired using an optical coherence tomography system. Images were corrected for refractive distortions and lens volume was calculated assuming rotational symmetry. The average change in lens volume was calculated and the relation between volume change and power change, and between volume change and stretching force, were quantified. Linear regressions of volume-power and volume-force plots were calculated. The mean (± SD) volume in the unstretched (accommodated) state was 97 ± 8 mm3. On average, there was a small but statistically significant (P = 0.002) increase in measured lens volume with stretching. The mean change in lens volume was +0.8 ± 1.3 mm3. The mean volume-power and volume-load slopes were -0.018 ± 0.058 mm3/D and +0.16 ± 0.40 mm3/g. Lens volume remains effectively constant during accommodation, with changes that are less than 1% on average. This result supports a hypothesis that the change in lens shape with accommodation is accompanied by a redistribution of tissue within the capsular bag without significant compression of the lens contents or fluid exchange through the capsule.

  6. Fast track-finding trigger processor for the SLAC/LBL Mark II Detector

    International Nuclear Information System (INIS)

    Brafman, H.; Breidenbach, M.; Hettel, R.; Himel, T.; Horelick, D.

    1977-10-01

    The SLAC/LBL Mark II Magnetic Detector consists of various particle detectors arranged in cylindrical symmetry located in and around an axial magnetic field. A versatile, programmable secondary trigger processor was designed and built to find curved tracks in the detector. The system operates at a 10 MHz clock rate with a total processing time of 34 μsec and is used to ''trigger'' the data processing computer, thereby rejecting background and greatly improving the data acquisition aspects of the detector-computer combination

  7. Increased Ac excision (iae): Arabidopsis thaliana mutations affecting Ac transposition

    International Nuclear Information System (INIS)

    Jarvis, P.; Belzile, F.; Page, T.; Dean, C.

    1997-01-01

    The maize transposable element Ac is highly active in the heterologous hosts tobacco and tomato, but shows very much reduced levels of activity in Arabidopsis. A mutagenesis experiment was undertaken with the aim of identifying Arabidopsis host factors responsible for the observed low levels of Ac activity. Seed from a line carrying a single copy of the Ac element inserted into the streptomycin phosphotransferase (SPT) reporter fusion, and which displayed typically low levels of Ac activity, were mutagenized using gamma rays. Nineteen mutants displaying high levels of somatic Ac activity, as judged by their highly variegated phenotypes, were isolated after screening the M2 generation on streptomycin-containing medium. The mutations fall into two complementation groups, iae1 and iae2, are unlinked to the SPT::Ac locus and segregate in a Mendelian fashion. The iae1 mutation is recessive and the iae2 mutation is semi-dominant. The iae1 and iae2 mutants show 550- and 70-fold increases, respectively, in the average number of Ac excision sectors per cotyledon. The IAE1 locus maps to chromosome 2, whereas the SPT::Ac reporter maps to chromosome 3. A molecular study of Ac activity in the iae1 mutant confirmed the very high levels of Ac excision predicted using the phenotypic assay, but revealed only low levels of Ac re-insertion. Analyses of germinal transposition in the iae1 mutant demonstrated an average germinal excision frequency of 3% and a frequency of independent Ac re-insertions following germinal excision of 22%. The iae mutants represents a possible means of improving the efficiency of Ac/Ds transposon tagging systems in Arabidopsis, and will enable the dissection of host involvement in Ac transposition and the mechanisms employed for controlling transposable element activity

  8. Technical Design Report for the FACET-II Project at SLAC National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-08-26

    Electrons can “surf” on waves of plasma – a hot gas of charged particles – gaining very high energies in very short distances. This approach, called plasma wakefield acceleration, has the potential to dramatically shrink the size and cost of particle accelerators. Research at the SLAC National Accelerator Laboratory has demonstrated that plasmas can provide 1,000 times the acceleration in a given distance compared with current technologies. Developing revolutionary and more efficient acceleration techniques that allow for an affordable high-energy collider has been the focus of FACET, a National User Facility at SLAC. FACET used part of SLAC’s two-mile-long linear accelerator to generate high-density beams of electrons and their antimatter counterparts, positrons. Research into plasma wakefield acceleration was the primary motivation for constructing FACET. In April 2016, FACET operations came to an end to make way for the second phase of SLAC’s x-ray laser, the LCLS-II, which will use part of the tunnel occupied by FACET. FACET-II is a new test facility to provide the unique capability to develop advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. FACET-II represents a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique.

  9. Analysis of causes of intraocular lens explantations in the material of Department of Ophthalmology, Medical University of Lodz.

    Science.gov (United States)

    Wilczyński, Michał; Wilczyńska, Olena; Omulecki, Wojciech

    2009-01-01

    Implantation of intraocular lenses (IOLS) has become a standard practice in cataract surgery, however, similar to any other type of surgery, using IOLs is not complication-free and sometimes explantation of intraocular lenses may be necessary. This study was to gather data and analyze causes of intraocular lens explantations, performed in the Department of Ophthalmology, Medical University of Łódź. The data were gathered from medical documentation of all patients who underwent intraocular lens removal from January 2003 to July 2006. The examined group consisted of 16 patients (16 eyes): 9 women (fraction 0.56), and 7 men (fraction 0.44), at the age from 21 to 82 years (mean age 62.4 years, SD +/- 15.5). In all patients IOL explantation was performed under local, peribulbar anaesthesia. Two groups of patients were distinguished: patients who had an anterior chamber lens explanted (3 patients, fraction 0.19) and patients who underwent posterior chamber lens explantation (13 patients, fraction 0.81). Causes of AC IOL explantations were: vaulting of the IOL (1 eye, fraction 0.06), luxation of the IOL to the vitreous cavity (1 eye, fraction 0.06), and painful eyeball after anterior chamber lens implantation (1 eye, fraction 0.06). Causes of PC IOL explantations were: subluxation of the IOL (6 eyes, fraction 0.38), luxation of the lens to the vitreous cavity (3 eyes, fraction 0.19), luxation of the lens to the anterior chamber (1 eye, fraction 0.06), endophthalmitis (2 eyes, fraction 0.13) and incorrect lens power (1 eye, fraction 0.06). In the majority of eyes (n = 13, fraction 0.81) the removed implant was replaced by another intraocular lens, but 3 eyes (fraction 0.19) were left aphakic. We did not observe serious intra- or early postoperative complications which might influence the final result of the operation.

  10. A 100 GeV SLAC Linac

    International Nuclear Information System (INIS)

    Farkas, Zoltan D

    2002-01-01

    The SLAC beam energy can be increased from the current 50 GeV to 100 GeV, if we change the operating frequency from the present 2856 MHz to 11424 MHz, using technology developed for the NLC. We replace the power distribution system with a proposed NLC distribution system as shown in Fig. 1. The four 3 meter s-band 820 nS fill time accelerator sections are replaced by six 2 meter x-band 120 nS fill time sections. Thus the accelerator length per klystron retains the same length, 12 meters. The 4050 65MW-3.5(micro)S klystrons are replaced by 75MW-1.5(micro)S permanent magnet klystrons developed here and in Japan. The present input to the klystrons would be multiplied by a factor of 4 and possibly amplified. The SLED [1] cavities have to be replaced. The increase in beam voltage is due to the higher elastance to group velocity ratio, higher compression ratio and higher unloaded to external Q ratio of the new SLED cavities. The average power input is reduced because of the narrower klystron pulse width and because the klystron electro-magnets are replaced by permanent magnets

  11. AutoLens: Automated Modeling of a Strong Lens's Light, Mass and Source

    Science.gov (United States)

    Nightingale, J. W.; Dye, S.; Massey, Richard J.

    2018-05-01

    This work presents AutoLens, the first entirely automated modeling suite for the analysis of galaxy-scale strong gravitational lenses. AutoLens simultaneously models the lens galaxy's light and mass whilst reconstructing the extended source galaxy on an adaptive pixel-grid. The method's approach to source-plane discretization is amorphous, adapting its clustering and regularization to the intrinsic properties of the lensed source. The lens's light is fitted using a superposition of Sersic functions, allowing AutoLens to cleanly deblend its light from the source. Single component mass models representing the lens's total mass density profile are demonstrated, which in conjunction with light modeling can detect central images using a centrally cored profile. Decomposed mass modeling is also shown, which can fully decouple a lens's light and dark matter and determine whether the two component are geometrically aligned. The complexity of the light and mass models are automatically chosen via Bayesian model comparison. These steps form AutoLens's automated analysis pipeline, such that all results in this work are generated without any user-intervention. This is rigorously tested on a large suite of simulated images, assessing its performance on a broad range of lens profiles, source morphologies and lensing geometries. The method's performance is excellent, with accurate light, mass and source profiles inferred for data sets representative of both existing Hubble imaging and future Euclid wide-field observations.

  12. AC Initiation System.

    Science.gov (United States)

    An ac initiation system is described which uses three ac transmission signals interlocked for safety by frequency, phase, and power discrimination...The ac initiation system is pre-armed by the application of two ac signals have the proper phases, and activates a load when an ac power signal of the proper frequency and power level is applied. (Author)

  13. Optical integration of Pancharatnam-Berry phase lens and dynamical phase lens

    International Nuclear Information System (INIS)

    Ke, Yougang; Liu, Yachao; Zhou, Junxiao; Liu, Yuanyuan; Luo, Hailu; Wen, Shuangchun

    2016-01-01

    In the optical system, most elements such as lens, prism, and optical fiber are made of silica glass. Therefore, integrating Pancharatnam-Berry phase elements into silica glass has potential applications in the optical system. In this paper, we take a lens, for example, which integrates a Pancharatnam-Berry phase lens into a conventional plano-convex lens. The spin states and positions of focal points can be modulated by controlling the polarization states of the incident beam. The proposed lens has a high transmission efficiency, and thereby acts as a simple and powerful tool to manipulate spin photons. Furthermore, the method can be conveniently extended to the optical fiber and laser cavity, and may provide a route to the design of the spin-photonic devices.

  14. Converging or Diverging Lens?

    Science.gov (United States)

    Branca, Mario

    2013-01-01

    Why does a lens magnify? Why does it shrink objects? Why does this happen? The activities that we propose here are useful in helping us to understand how lenses work, and they show that the same lens can have different magnification capabilities. A converging lens can also act as a diverging lens. (Contains 4 figures.)

  15. Dipole magnets for the SLAC 50 GeV A-Line upgrade

    International Nuclear Information System (INIS)

    Erickson, R.; DeBarger, S.; Spencer, C.M.; Wolf, Z.

    1995-05-01

    The SLAC A-Line is a transport system originally designed to deliver electron beams of up to 25 GeV to fixed target experiments in End Station A. To raise the beam energy capability of the A-Line to 52 GeV, the eight original bending magnets, plus four more of the same type, have been modified by reducing their gaps and adding trim windings to compensate for energy loss due to synchrotron radiation. In this paper the authors describe the modifications that have been completed, and they compare test and measurement results with predicted performance

  16. Upgrade of the SLAC SLED II Pulse Compression System Based on Recent High Power Tests

    International Nuclear Information System (INIS)

    Vlieks, A.E.; Fowkes, W.R.; Loewen, R.J.; Tantawi, S.G.

    2011-01-01

    In the Next Linear Collider (NLC) it is expected that the high power rf components be able to handle peak power levels in excess of 400 MW. We present recent results of high power tests designed to investigate the RF breakdown limits of the X-band pulse compression system used at SLAC. (SLED-II). Results of these tests show that both the TE 01 -TE 10 mode converter and the 4-port hybrid have a maximum useful power limit of 220-250 MW. Based on these tests, modifications of these components have been undertaken to improve their peak field handling capability. Results of these modifications will be presented. As part of an international effort to develop a new 0.5-1.5 TeV electron-positron linear collider for the 21st century, SLAC has been working towards a design, referred to as 'The Next Linear Collider' (NLC), which will operate at 11.424 GHz and utilize 50-75 MW klystrons as rf power sources. One of the major challenges in this design, or any other design, is how to generate and efficiently transport extremely high rf power from a source to an accelerator structure. SLAC has been investigating various methods of 'pulse compressing' a relatively wide rf pulse ((ge) 1 μs) from a klystron into a narrower, but more intense, pulse. Currently a SLED-II pulse compression scheme is being used at SLAC in the NLC Test Accelerator (NLCTA) and in the Accelerator Structures Test Area (ASTA) to provide high rf power for accelerator and component testing. In ASTA, a 1.05 μs pulse from a 50 MW klystron was successfully pulse compressed to 205 MW with a pulse width of 150 ns. Since operation in NLC will require generating and transporting rf power in excess of 400 MW it was decided to test the breakdown limits of the SLED-II rf components in ASTA with rf power up to the maximum available of 400 MW. This required the combining of power from two 50 MW klystrons and feeding the summed power into the SLED-II pulse compressor. Results from this experiment demonstrated that two of

  17. Placement of a crystalline lens and intraocular lens: Retinal image quality.

    Science.gov (United States)

    Siedlecki, Damian; Nowak, Jerzy; Zajac, Marek

    2006-01-01

    The influence of changes of both crystalline lens and intraocular lens (IOL) misalignment on the retinal image quality was investigated. The optical model of the eye used in investigations was the Liou-Brennan model, which is commonly considered as one of the most anatomically accurate. The original crystalline lens from this model was replaced with an IOL, made of rigid polymethylmethacrylate, in a way that recommend obligatory procedures. The modifications that were made both for crystalline lens and IOL were the longitudinal, the transversal, and the angular displacement.

  18. The analog processing system for the Liquid Argon Calorimeter for SLD at SLAC

    International Nuclear Information System (INIS)

    Haller, G.M.; Nelson, D.; Freytag, D.R.

    1986-09-01

    The analog processing system for the Liquid Argon Calorimeter for the SLD project at SLAC is described. Amplification, storage of the analog information, and multiplexing is realized on specially developed hybrids, which will be mounted directly on the detector. This leads to a substantial reduction of the cable plant. Test results for the amplifier and for the sampling and multiplexing hybrid (CDU hybrid) are presented. The latter hybird contains a custom monolithic device, the Calorimeter Data Unit

  19. Refractive neutron lens

    International Nuclear Information System (INIS)

    Petrov, P.V.; Kolchevsky, N.N.

    2013-01-01

    Model of the refractive neutron lens is proposed. System of N lenses acts as one thin lens with a complex refraction index n*. The maximum number N max of individual lenses for 'thick' neutron lens is calculated. Refractive neutron lens properties (resolution, focal depth) as function of resolution factor F 0 =ρbc/μ and depth of field factor dF 0 =λF 0 =λρbc/μ are calculated. It is shown that micro resolution of the refractive neutron optics is far from the wavelength in size and its open possibilities for progress in refractive neutron optics. (authors)

  20. Thermal stress analysis of the SLAC moveable mask. Addendum 2

    International Nuclear Information System (INIS)

    Johnson, G.L.

    1985-01-01

    X-ray beams emerging from the new SLAC electron-positron storage ring (PEP) can impinge on the walls of tangential divertor channels. A moveable mask made of 6061-T6 aluminum is installed in the channel to limit wall heating. The mask is cooled with water flowing axially at 30 0 C. Beam strikes on the mask cause highly localized heating in the channel structure. Analyses were completed to determine the temperatures and thermally-induced stresses due to this heating. The current design and operating conditions should result in the entrance to the moveable mask operating at a peak temperature of 88 0 C with a peak thermal stress at 19% of the yield of 6061-T6 aluminum

  1. SLAC collider injector, RF-drive synchronization and trigger electronics, and 15-AMP thermionic-gun development

    International Nuclear Information System (INIS)

    Koontz, R.; Miller, R.; McKinney, T.; Wilmunder, A.

    1981-02-01

    The rf drive system for the Collider Injector Development (EL CID) including laser timing, subharmonic buncher drive and phasing, and accelerator rf drive is described. The rf synchronized master trigger generation scheme for the collider is outlined. Also, a 15 amp peak, 200 kV short pulse gun being developed at SLAC as a backup to the Sinclair laser gun is described

  2. Exchange of tears under a contact lens is driven by distortions of the contact lens.

    Science.gov (United States)

    Maki, Kara L; Ross, David S

    2014-12-01

    We studied the flow of the post-lens tear film under a soft contact lens to understand how the design parameters of contact lenses can affect ocular health. When a soft contact lens is inserted, the blinking eyelid causes the lens to stretch in order to conform to the shape of the eye. The deformed contact lens acts to assume its un-deformed shape and thus generates a suction pressure in the post-lens tear film. In consequence, the post-lens tear fluid moves; it responds to the suction pressure. The suction pressure may draw in fresh fluid from the edge of the lens, or it may eject fluid there, as the lens reassumes its un-deformed shape. In this article, we develop a mathematical model of the flow of the post-lens tear fluid in response to the mechanical suction pressure of a deformed contact lens. We predict the amount of exchange of fluid exchange under a contact lens and we explore the influence of the eye's shape on the rate of exchange of fluid. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  3. Peripheral Defocus of the Monkey Crystalline Lens With Accommodation in a Lens Stretcher

    Science.gov (United States)

    Maceo Heilman, Bianca; Manns, Fabrice; Ruggeri, Marco; Ho, Arthur; Gonzalez, Alex; Rowaan, Cor; Bernal, Andres; Arrieta, Esdras; Parel, Jean-Marie

    2018-01-01

    Purpose To characterize the peripheral defocus of the monkey crystalline lens and its changes with accommodation. Methods Experiments were performed on 15 lenses from 11 cynomolgus monkey eyes (age: 3.8–12.4 years, postmortem time: 33.5 ± 15.3 hours). The tissue was mounted in a motorized lens stretcher to allow for measurements of the lens in the accommodated (unstretched) and unaccommodated (stretched) states. A custom-built combined laser ray tracing and optical coherence tomography system was used to measure the paraxial on-axis and off-axis lens power for delivery angles ranging from −20° to +20° (in air). For each delivery angle, peripheral defocus was quantified as the difference between paraxial off-axis and on-axis power. The peripheral defocus of the lens was compared in the unstretched and stretched states. Results On average, the paraxial on-axis lens power was 52.0 ± 3.4 D in the unstretched state and 32.5 ± 5.1 D in the stretched state. In both states, the lens power increased with increasing delivery angle. From 0° to +20°, the relative peripheral lens power increased by 10.7 ± 1.4 D in the unstretched state and 7.5 ± 1.6 D in the stretched state. The change in field curvature with accommodation was statistically significant (P lens has greater curvature or relative peripheral power. Conclusions The cynomolgus monkey lens has significant accommodation-dependent curvature of field, which suggests that the lens asserts a significant contribution to the peripheral optical performance of the eye that also varies with the state of accommodation.

  4. Introduction to high-energy physics and the Stanford Linear Accelerator Center (SLAC)

    International Nuclear Information System (INIS)

    Clearwater, S.

    1983-03-01

    The type of research done at SLAC is called High Energy Physics, or Particle Physics. This is basic research in the study of fundamental particles and their interactions. Basic research is research for the sake of learning something. Any practical application cannot be predicted, the understanding is the end in itself. Interactions are how particles behave toward one another, for example some particles attract one another while others repel and still others ignore each other. Interactions of elementary particles are studied to reveal the underlying structure of the universe

  5. Introduction to high-energy physics and the Stanford Linear Accelerator Center (SLAC)

    Energy Technology Data Exchange (ETDEWEB)

    Clearwater, S.

    1983-03-01

    The type of research done at SLAC is called High Energy Physics, or Particle Physics. This is basic research in the study of fundamental particles and their interactions. Basic research is research for the sake of learning something. Any practical application cannot be predicted, the understanding is the end in itself. Interactions are how particles behave toward one another, for example some particles attract one another while others repel and still others ignore each other. Interactions of elementary particles are studied to reveal the underlying structure of the universe.

  6. The 50 GeV program at SLAC

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1994-03-01

    SLAC has undertaken a modes programs to upgrade the beam energy for fixed target experiments to 50 GeV. This upgrade is possible due to the previous extensive development work on the linac accelerating gradient for the SLC, which has been operational for over five years. The SLC can deliver a beam of energy up to 60 GeV using a pulse compression technique in the rf system which trades pulse length for a higher pulse amplitude. This mode of operation has been reliable and routine for the SLC. However the beam line transport which takes electrons or positrons from the end of the linac to the target in End Station A has not been upgraded from the original design energy of 25 GeV. The 50 GeV upgrade for the fixed target experiments consists in modifying and increasing the number of beam line dipole magnets to reach 50 GeV, plus modernization of the beam line instrumentation and controls. The plans for spin structure experiments using electron beams at energies up to 50 GeV are described

  7. Study on ac losses of HTS coil carrying ac transport current

    International Nuclear Information System (INIS)

    Dai Taozhen; Tang Yuejin; Li Jingdong; Zhou Yusheng; Cheng Shijie; Pan Yuan

    2005-01-01

    Ac loss has an important influence on the thermal performances of HTS coil. It is necessary to quantify ac loss to ascertain its impact on coil stability and for sizing the coil refrigeration system. In this paper, we analyzed in detail the ac loss components, hysteresis loss, eddy loss and flux flow loss in the pancake HTS coil carrying ac transport current by finite element method. We also investigated the distribution of the ac losses in the coil to study the effects of magnetic field distribution on ac losses

  8. Compliance among soft contact lens wearers.

    Science.gov (United States)

    Kuzman, Tomislav; Kutija, Marija Barisić; Masnec, Sanja; Jandroković, Sonja; Mrazovac, Danijela; Jurisić, Darija; Skegro, Ivan; Kalauz, Miro; Kordić, Rajko

    2014-12-01

    Contact lens compliance is proven to be crucial for preventing lens wear-related complications because of the interdependence of the steps in lens care regime and their influence on lens system microbial contamination. Awareness of the patients' lens handling compliance as well as correct recognition of non-compliant behaviours is the basis for creating more targeted strategies for patient education. The aim of this study was to investigate compliance among soft contact lens (SCL) wearers in different aspects of lens care handling and wearing habits. In our research 50 asymptomatic lens wearers filled out a questionnaire containing demographic data, lens type, hygiene and wearing habits, lenses and lens care system replacement schedule and self-evaluation of contact lens handling hygiene. We established criteria of compliance according to available manufacturer's recommendations, prior literature and our clinical experience. Only 2 (4%) of patients were fully compliant SCL wearers. The most common non-compliant behaviours were insufficient lens solution soaking time (62%), followed by failure to daily exchange lens case solution and showering while wearing lenses. 44% of patients reported storing lenses in saline solution. Mean lens storage case replacement was 3.6 months, with up to 78% patients replacing lens case at least once in 3 months. Average grade in self evaluating level of compliance was very good (4 +/- 0.78) (from 1-poor level of hygiene to 5-great level of hygiene). Lens wearers who reported excessive daily lens wear and more than 10 years of lens wearing experience were also found to be less compliant with other lens system care procedures. (t = -2.99, df=47, p rate, self grading was relatively high. Therefore, these results indicate the need for patient education and encouragement of better lens wearing habits and all of the lens maintenance steps at each patient visit.

  9. Comparison of clear lens extraction and collamer lens implantation in high myopia

    Directory of Open Access Journals (Sweden)

    Ahmed M Emarah

    2010-05-01

    Full Text Available Ahmed M Emarah, Mostafa A El-Helw, Hazem M YassinCairo University, Cairo, EgyptAim: To compare the outcomes of clear lens extraction and collamer lens implantation in high myopia.Patients and methods: Myopic patients younger than 40 years old with more than 12 diopters of myopia or who were not fit for laser-assisted in situ keratomileusis were included. Group 1 comprised patients undergoing clear lens extraction and Group 2 patients received the Visian implantable collamer lens. Outcome and complications were evaluated.Results: Postoperative best corrected visual acuity was -0.61 ± 0.18 in Group 1 and 0.79 ± 0.16 in Group 2. In Group 1, 71.4% achieved a postoperative uncorrected visual acuity better than the preoperative best corrected visual acuity, while only 51.8% patients achieved this in Group 2. Intraocular pressure decreased by 12.55% in Group 1, and increased by 15.11% in Group 2. Corneal endothelial cell density decreased by 4.47% in Group 1 and decreased by 5.67% in Group 2. Posterior capsule opacification occurred in Group 1. In Group 2, lens opacification occurred in 11.11%, significant pigment dispersion in 3.7%, and pupillary block glaucoma in 3.7%.Conclusion: Clear lens extraction presents less of a financial load up front, and less likelihood of the need for a secondary intervention in the future. Clear lens extraction is a more viable solution in developing countries with limited financial resources.Keywords: clear lens extraction, implantable collamer lens, myopia

  10. Multi-phase AC/AC step-down converter for distribution systems

    Science.gov (United States)

    Aeloiza, Eddy C.; Burgos, Rolando P.

    2017-10-25

    A step-down AC/AC converter for use in an electric distribution system includes at least one chopper circuit for each one of a plurality of phases of the AC power, each chopper circuit including a four-quadrant switch coupled in series between primary and secondary sides of the chopper circuit and a current-bidirectional two-quadrant switch coupled between the secondary side of the chopper circuit and a common node. Each current-bidirectional two-quadrant switch is oriented in the same direction, with respect to the secondary side of the corresponding chopper circuit and the common node. The converter further includes a control circuit configured to pulse-width-modulate control inputs of the switches, to convert a first multiphase AC voltage at the primary sides of the chopper circuits to a second multiphase AC voltage at the secondary sides of the chopper circuits, the second multiphase AC voltage being lower in voltage than the first multiphase AC voltage.

  11. Changes in lens stiffness due to capsular opacification in accommodative lens refilling

    NARCIS (Netherlands)

    Nibourg, Lisanne M.; Sharma, Prashant K.; van Kooten, Theo G.; Koopmans, Steven A.

    Accommodation may be restored to presbyopic lenses by refilling the lens capsular bag with a soft polymer. After this accommodative lens refilling prevention of capsular opacification is a requirement, since capsular opacification leads to a decreased clarity of the refilled lens. It has been

  12. TU-E-201-03: Eye Lens Dosimetry in Radiotherapy Using Contact Lens-Shaped Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. [Seoul National University Hospital (Korea, Republic of)

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  13. TU-E-201-03: Eye Lens Dosimetry in Radiotherapy Using Contact Lens-Shaped Applicator

    International Nuclear Information System (INIS)

    Park, J.

    2015-01-01

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  14. Contact Lens-Related Eye Infections

    Science.gov (United States)

    ... Español Eye Health / Eye Health A-Z Contact Lens-Related Eye Infections Sections Contact Lens-Related Eye ... Six Steps to Avoid Contact Lens Infections Contact Lens-Related Eye Infections Leer en Español: Infecciones relacionadas ...

  15. Present and future colliding beam facilities at SLAC

    International Nuclear Information System (INIS)

    Wiedemann, H.

    1977-07-01

    In April 1972, the 3-GeV electron positron storage ring, SPEAR, was put into operation at the end of the linear accelerator at Stanford. By the recent discoveries in high energy physics the value of electron-positron storage rings for high energy physics has been clearly demonstrated. This development certainly encouraged the relatively early funding of the new electron-positron storage ring, PEP, at SLAC. In addition to its role as a particle physics research tool, SPEAR has been and remains a priceless model or prototype for larger storage rings like PEP. A few of the recent observations in SPEAR which have important implications to the design of PEP are described. Although the PEP design follows closely the SPEAR concept in many respects, it has its own distinctive and important features which are discussed in detail. Topics discussed include synchrotron-betatron resonances, beam losses, beam bunching, PEP design luminosity and energy, chromaticity correction in PEP, and the high energy cabability of PEP

  16. Vortex gas lens

    Science.gov (United States)

    Bogdanoff, David W.; Berschauer, Andrew; Parker, Timothy W.; Vickers, Jesse E.

    1989-01-01

    A vortex gas lens concept is presented. Such a lens has a potential power density capability of 10 to the 9th - 10 to the 10th w/sq cm. An experimental prototype was constructed, and the divergence half angle of the exiting beam was measured as a function of the lens operating parameters. Reasonably good agreement is found between the experimental results and theoretical calculations. The expanded beam was observed to be steady, and no strong, potentially beam-degrading jets were found to issue from the ends of the lens. Estimates of random beam deflection angles to be expected due to boundary layer noise are presented; these angles are very small.

  17. Primary anterior chamber intraocular lens for the treatment of severe crystalline lens subluxation.

    Science.gov (United States)

    Hoffman, Richard S; Fine, I Howard; Packer, Mark

    2009-10-01

    Subluxated cataractous and clear lenses are commonly treated by limbal or pars plana lensectomy followed by primary or secondary intraocular lens (IOL) implantation. Adjunctive capsular prosthetic devices have facilitated lens removal and IOL centration in these challenging cases but have also added complexity and potential complications to the procedure. Although crystalline lens extraction may be required to clear the visual axis in mild to moderate lens subluxations, we propose insertion of a primary anterior chamber IOL without lens extraction in severe subluxations when the eye is optically aphakic or can be made functionally aphakic following neodymium:YAG laser zonulysis. Two cases demonstrating this approach are presented.

  18. ACAC Converters for UPS

    Directory of Open Access Journals (Sweden)

    Rusalin Lucian R. Păun

    2008-05-01

    Full Text Available This paper propose a new control technique forsingle – phase ACAC converters used for a on-line UPSwith a good dynamic response, a reduced-partscomponents, a good output characteristic, a good powerfactorcorrection(PFC. This converter no needs anisolation transformer. A power factor correction rectifierand an inverter with the proposed control scheme has beendesigned and simulated using Caspoc2007, validating theconcept.

  19. Z0 physics from the Mark II at the SLC [SLAC Linear Collider

    International Nuclear Information System (INIS)

    Abrams, G.S.

    1989-06-01

    The MARK II detector has started to take data at the new SLAC Linear Collider. The novel aspects of the accelerator and of the MARK II are briefly described. Displays of event pictures from some of the early-on data are presented to illustrate the quality of the data. A first presentation of the results of an energy scan near the Z 0 mass that is currently in progress shows the expected resonant enhancement near 91 GeV. 2 refs., 23 figs., 1 tab

  20. Performance of AC/graphite capacitors at high weight ratios of AC/graphite

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongyu [IM and T Ltd., Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Yoshio, Masaki [Advanced Research Center, Department of Applied Chemistry, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)

    2008-03-01

    The effect of negative to positive electrode materials' weight ratio on the electrochemical performance of both activated carbon (AC)/AC and AC/graphite capacitors has been investigated, especially in the terms of capacity and cycle-ability. The limited capacity charge mode has been proposed to improve the cycle performance of AC/graphite capacitors at high weight ratios of AC/graphite. (author)

  1. Capsular 'pits' in the human lens.

    OpenAIRE

    Harris, M. L.; Brown, N. A.; Shun-Shin, G. A.; Smith, G. T.

    1992-01-01

    The lens capsule is an atypical basement membrane surrounding the lens epithelial cells and lens fibres which make up the remainder of the human lens. A seemingly unreported morphological change visible in the lens capsule with the biomicroscope is described.

  2. TOSCA calculations and measurements for the SLAC SLC damping ring dipole magnet

    International Nuclear Information System (INIS)

    Early, R.A.; Cobb, J.K.

    1985-01-01

    The SLAC damping ring dipole magnet was originally designed with removable nose pieces at the ends. Recently, a set of magnetic measurements was taken of the vertical component of induction along the center of the magnet for four different pole-end configurations and several current settings. The three dimensional computer code TOSCA, which is currently installed on the National Magnetic Fusion Energy Computer Center's Cray X-MP, was used to computer field values for the four configurations at current settings near saturation. Comparisons were made for magnetic induction as well as effective magnetic lengths for the different configurations

  3. The proposed alignment system for the Final Focus Test Beam at SLAC

    International Nuclear Information System (INIS)

    Ruland, R.E.; Fischer, G.E.

    1990-09-01

    This report describes the current state of work in progress with respect to the geometry, alignment requirements, scenarios, and hardware for meeting the tolerances of the Final Focus Test Beam (FFTB) at SLAC. The methods and systems proposed acknowledge that component motion at the micron level, from whatever cause (ground motion, thermal effects, etc.) must be measured on-line and compensated for on relatively short time scales. To provide an integrated alignment/positioning package, some unique designs for reference systems, calibration of effect electric and magnetic centers, and component movers are introduced. 24 refs., 28 figs

  4. Nucleon resonance electroproduction at high momentum transers: Results from SLAC and suggestions for CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Keppel, C. [Virginia Union Univ., Richmond, VA (United States)

    1994-04-01

    Nucleon resonance electroproduction results from SLAC Experiment E14OX are presented. A CEBAF facility with doubled energy would enable similar high momentum transfer measurements to be made with greater accuracy. Of particular interest are the Delta P{sub 33}(1232) resonance form factor and R = {sigma}{sub L}/{sigma}{sub T}, the ratio of the longitudinal and transverse components of the cross section. A suggestion is made to study these quantities in conjunction with Bloom-Gilman duality.

  5. A high excitation magnetic quadrupole lens quadruplet incorporating a single octupole lens for a low spherical aberration probe forming lens system

    Science.gov (United States)

    Dou, Yanxin; Jamieson, David N.; Liu, Jianli; Li, Liyi

    2018-03-01

    This paper describes the design of a new probe forming lens system consisting of a high excitation magnetic quadrupole lens quadruplet that incorporates a single magnetic octupole lens. This system achieves both a high demagnification and a low spherical aberration compared to conventional high excitation systems and is intended for deployment for the Harbin 300 MeV proton microprobe for applications in space science and ion beam therapy. This relative simplicity of the ion optical design to include a single octupole lens minimizes the risks associated with the constructional and operational precision usually needed for the probe forming lens system and this system could also be deployed in microprobe systems that operate with less magnetically rigid ions. The design of the new system is validated with reference to two independent ion optical computer codes.

  6. Objective lens

    Science.gov (United States)

    Olczak, Eugene G. (Inventor)

    2011-01-01

    An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

  7. Contact Lens Care

    Science.gov (United States)

    ... Consumers Consumer Information by Audience For Women Contact Lens Care Share Tweet Linkedin Pin it More sharing ... www.fda.gov/medwatch Learn More about Contact Lens Care Other Tips on Contact Lenses Decorative Contact ...

  8. Ground motion measurements at the LBL Light Source site, the Bevatron and at SLAC

    International Nuclear Information System (INIS)

    Green, M.A.; Majer, E.I.; More, V.D.; O'Connell, D.R.; Shilling, R.C.

    1986-12-01

    This report describes the technique for measuring ground motion at the site of the 1.0 to 2.0 GeV Synchrotron Radiation Facility which was known as the Advanced Light Source (in 1983 when the measurements were taken). The results of ground motion measurements at the Light Source site at Building 6 at LBL are presented. As comparison, ground motion measurements were made at the Byerly Tunnel, the Bevatron, Blackberry Canyon, and SLAC at the Spear Ring. Ground Motion at the Light Source site was measured in a band from 4 to 100 Hz. The measured noise is primarily local in origin and is not easily transported through LBL soils. The background ground motion is for the most part less than 0.1 microns. Localized truck traffic near Building 6 and the operation of the cranes in the building can result in local ground motions of a micron or more for short periods of time. The background motion at Building 6 is between 1 and 2 orders of magnitude higher than ground motion in a quiet seismic tunnel, which is representative of quiet sites worldwide. The magnitude of the ground motions at SLAC and the Bevatron are comparable to ground motions measured at the Building 6 Light Source site. However, the frequency signature of each site is very different

  9. Advocacy for the Archives and History Office of the SLAC National Accelerator Laboratory: Stages and Methods

    International Nuclear Information System (INIS)

    Deken, J.

    2009-01-01

    Advocating for the good of the SLAC Archives and History Office (AHO) has not been a one-time affair, nor has it been a one-method procedure. It has required taking time to ascertain the current and perhaps predict the future climate of the Laboratory, and it has required developing and implementing a portfolio of approaches to the goal of building a stronger archive program by strengthening and appropriately expanding its resources. Among the successful tools in the AHO advocacy portfolio, the Archives Program Review Committee has been the most visible. The Committee and the role it serves as well as other formal and informal advocacy efforts are the focus of this case study My remarks today will begin with a brief introduction to advocacy and outreach as I understand them, and with a description of the Archives and History Office's efforts to understand and work within the corporate culture of the SLAC National Accelerator Laboratory. I will then share with you some of the tools we have employed to advocate for the Archives and History Office programs and activities; and finally, I will talk about how well - or badly - those tools have served us over the past decade.

  10. Oxygen transport through soft contact lens and cornea: Lens characterization and metabolic modeling

    Science.gov (United States)

    Chhabra, Mahendra

    The human cornea requires oxygen to sustain metabolic processes critical for its normal functioning. Any restriction to corneal oxygen supply from the external environment (e.g., by wearing a low oxygen-permeability contact lens) can lead to hypoxia, which may cause corneal edema (swelling), limbal hyperemia, neovascularization, and corneal acidosis. The need for adequate oxygen to the cornea is a major driving force for research and development of hypertransmissible soft contact lenses (SCLs). Currently, there is no standard technique for measuring oxygen permeability (Dk) of hypertransmissible silicone-hydrogel SCLs. In this work, an electrochemistry-based polarographic apparatus was designed, built, and operated to measure oxygen permeability in hypertransmissible SCLs. Unlike conventional methods where a range of lens thickness is needed for determining oxygen permeabilities of SCLs, this apparatus requires only a single lens thickness. The single-lens permeameter provides a reliable, efficient, and economic tool for measuring oxygen permeabilities of commercial hypertransmissible SCLs. The single-lens permeameter measures not only the product Dk, but, following modification, it measures separately diffusivity, D, and solubility, k, of oxygen in hypertransmissible SCLs. These properties are critical for designing better lens materials that ensure sufficient oxygen supply to the cornea. Metabolism of oxygen in the cornea is influenced by contact-lens-induced hypoxia, diseases such as diabetes, surgery, and drug treatment, Thus, estimation of the in-vivo corneal oxygen consumption rate is essential for gauging adequate oxygen supply to the cornea. Therefore, we have developed an unsteady-state reactive-diffusion model for the cornea-contact-lens system to determine in-vivo human corneal oxygen-consumption rate. Finally, a metabolic model was developed to determine the relation between contact-lens oxygen transmissibility (Dk/L) and corneal oxygen deficiency. A

  11. Computing and data handling recent experiences at Fermilab and SLAC

    International Nuclear Information System (INIS)

    Cooper, P.S.

    1990-01-01

    Computing has become evermore central to the doing of high energy physics. There are now major second and third generation experiments for which the largest single cost is computing. At the same time the availability of ''cheap'' computing has made possible experiments which were previously considered infeasible. The result of this trend has been an explosion of computing and computing needs. I will review here the magnitude of the problem, as seen at Fermilab and SLAC, and the present methods for dealing with it. I will then undertake the dangerous assignment of projecting the needs and solutions forthcoming in the next few years at both laboratories. I will concentrate on the ''offline'' problem; the process of turning terabytes of data tapes into pages of physics journals. 5 refs., 4 figs., 4 tabs

  12. Crystalline lens power and refractive error.

    Science.gov (United States)

    Iribarren, Rafael; Morgan, Ian G; Nangia, Vinay; Jonas, Jost B

    2012-02-01

    To study the relationships between the refractive power of the crystalline lens, overall refractive error of the eye, and degree of nuclear cataract. All phakic participants of the population-based Central India Eye and Medical Study with an age of 50+ years were included. Calculation of the refractive lens power was based on distance noncycloplegic refractive error, corneal refractive power, anterior chamber depth, lens thickness, and axial length according to Bennett's formula. The study included 1885 subjects. Mean refractive lens power was 25.5 ± 3.0 D (range, 13.9-36.6). After adjustment for age and sex, the standardized correlation coefficients (β) of the association with the ocular refractive error were highest for crystalline lens power (β = -0.41; P lens opacity grade (β = -0.42; P lens power (β = -0.95), lower corneal refractive power (β = -0.76), higher lens thickness (β = 0.30), deeper anterior chamber (β = 0.28), and less marked nuclear lens opacity (β = -0.05). Lens thickness was significantly lower in eyes with greater nuclear opacity. Variations in refractive error in adults aged 50+ years were mostly influenced by variations in axial length and in crystalline lens refractive power, followed by variations in corneal refractive power, and, to a minor degree, by variations in lens thickness and anterior chamber depth.

  13. Characteristics of the thick, compound refractive lens

    International Nuclear Information System (INIS)

    Pantell, Richard H.; Feinstein, Joseph; Beguiristain, H. Raul; Piestrup, Melvin A.; Gary, Charles K.; Cremer, Jay T.

    2003-01-01

    A compound refractive lens (CRL), consisting of a series of N closely spaced lens elements each of which contributes a small fraction of the total focusing, can be used to focus x rays or neutrons. The thickness of a CRL can be comparable to its focal length, whereupon a thick-lens analysis must be performed. In contrast with the conventional optical lens, where the ray inside the lens follows a straight line, the ray inside the CRL is continually changing direction because of the multiple refracting surfaces. Thus the matrix representation for the thick CRL is quite different from that for the thick optical lens. Principal planes can be defined such that the thick-lens matrix can be converted to that of a thin lens. For a thick lens the focal length is greater than for a thin lens with the same lens curvature, but this lengthening effect is less for the CRL than for the conventional optical lens

  14. AcEST: DK949629 [AcEST

    Lifescience Database Archive (English)

    Full Text Available Thread biopolymer filament subunit gamma OS... 38 0.062 sp|P18490|PCX_DROME Protein pecanex OS=Drosophila me...AMMEGSSSGGHSMYSSSSM 575 >sp|P18490|PCX_DROME Protein pecanex OS=Drosophila melanogaster GN=pcx PE=2 SV=3 Len

  15. TU-E-201-01: Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionists

    Energy Technology Data Exchange (ETDEWEB)

    Rehani, M. [Massachusetts General Hospital (United States)

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  16. TU-E-201-01: Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionists

    International Nuclear Information System (INIS)

    Rehani, M.

    2015-01-01

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  17. DISSECTING THE GRAVITATIONAL LENS B1608+656. I. LENS POTENTIAL RECONSTRUCTION

    NARCIS (Netherlands)

    Suyu, S. H.; Marshall, P. J.; Blandford, R. D.; Fassnacht, C. D.; Koopmans, L. V. E.; McKean, J. P.; Treu, T.

    2009-01-01

    Strong gravitational lensing is a powerful technique for probing galaxy mass distributions and for measuring cosmological parameters. Lens systems with extended source-intensity distributions are particularly useful for this purpose since they provide additional constraints on the lens potential (

  18. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, Mike A. (Albuquerque, NM); Foreman, Larry R. (Los Alamos, NM)

    1997-01-01

    This invention describes a method for fabricating an intraocular lens made rom clear Teflon.TM., Mylar.TM., or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube.

  19. SLAC Scanner Processor applications in the data acquisition system for the upgraded Mark II detector

    International Nuclear Information System (INIS)

    Barklow, T.; Glanzman, T.; Lankford, A.J.; Riles, K.

    1985-09-01

    The SLAC Scanner Processor is a general purpose, programmable FASTBUS crate/cable master/slave module. This device plays a central role in the readout, buffering and pre-processing of data from the upgraded Mark II detector's new central drift chamber. In addition to data readout, the SSPs assist in a variety of other services, such as detector calibration, FASTBUS system management, FASTBUS system initialization and verification, and FASTBUS module testing. 9 refs., 1 fig., 2 tabs

  20. Straylight Measurements in Contact Lens Wear

    NARCIS (Netherlands)

    van der Meulen, Ivanka J. E.; Engelbrecht, Leonore A.; van Vliet, Johannes M. J.; Lapid-Gortzak, Ruth; Nieuwendaal, Carla P.; Mourits, Maarten P.; Schlingemann, Reinier O.; van den Berg, Thomas J. T. P.

    2010-01-01

    Purpose: (1) To quantify the effect of contact lens wear on straylight in rigid and soft contact lens wearers and (2) to relate findings to morphological changes and subjective complaints. Methods: Straylight was measured using the Oculus C-Quant during contact lens wear and after contact lens

  1. SLAC's Polarized Electron Source LaserSystem and Minimization of Helicity Correlations for the E-158 Parity Violation Experiment

    CERN Document Server

    Humensky, T

    2002-01-01

    SLAC E-158 is an experiment designed to make the first measurement of parity violation in Moeller scattering. E-158 will measure the right-left cross-section asymmetry, A sub L sub R sup M sup o sup e sup l sup l sup e sup r , in the elastic scattering of a 45-GeV polarized electron beam off unpolarized electrons in a liquid hydrogen target. E-158 plans to measure the expected Standard Model asymmetry of approx 10 sup - sup 7 to an accuracy of better than 10 sup - sup 8. To make this measurement, the polarized electron source requires for operation an intense circularly polarized laser beam and the ability to quickly switch between right- and left-helicity polarization states with minimal right-left helicity-correlated asymmetries in the resulting beam parameters (intensity, position, angle, spot size, and energy), sup b sup e sup a sup m A sub L sub R 's. This laser beam is produced by a unique SLAC-designed flashlamp-pumped Ti:Sapphire laser and is propagated through a carefully designed set of polarization...

  2. Quadrupole magnetic lens

    International Nuclear Information System (INIS)

    Piskunov, V.A.

    1981-01-01

    The following connection of windings of electromagnet is suggested for simplification of the design of qUadrupole magnetic lens intended for use in radiotechnical and electron-optical devices. The mentioned windings are connected with each other by a bridge scheme and the variable resistors are switched in its diagonals in the lens containing four electromagnet with windings connected with two variable resistors the mobile contacts of which are connected with a direct current source. Current redistribution between left windings and right windings takes place at shift of mobile contact of variable resistor, and current redistribution between upper and low coils of electromagnets takes place at shifting mobile contact of the other variable resistor. In this case smooth and independent electron-optical misalignment of lens by two mutually perpendicular directions proceeds. Use of the given design of the lens in the oscillograph permits to use printing assembly for alignment plate and to reduce the number of connections at the expense of decreasing the number of resistors

  3. AcEST: BP911450 [AcEST

    Lifescience Database Archive (English)

    Full Text Available EGU_VZVD Large tegument protein OS=Varicella-zoster virus (strain Dumas) Align length 93 Score (bit) 31.2 E-...8.3 >sp|P09278|TEGU_VZVD Large tegument protein OS=Varicella-zoster virus (strain Dumas) GN=22 PE=3 SV=1 Len

  4. Contact lens surface by electron beam

    International Nuclear Information System (INIS)

    Shin, Jung Hyuck; Lee, Suk Ju; Hwang, Kwang Ha; Jeon Jin

    2011-01-01

    Contact lens materials needs good biocompatibility, high refractive index, high optical transparency, high water content etc. Surface treat method by using plasma and radiation can modify the physical and/or chemical properties of the contact lens surface. Radiation technology such as electron beam irradiation can apply to polymerization reaction and enhance the functionality of the polymer.The purpose of this study is to modify of contact lens surface by using Eb irradiation technology. Electron beam was irradiated to the contact lens surface which was synthesized thermal polymerization method and commercial contact lens to modify physical and chemical properties. Ft-IR, XP, UV-vis spectrophotometer, water content, oxygen trans-metastability were used to characterize the surface state, physicochemical, and optical property of the contact lens treated with Eb. The water content and oxygen transmissibility of the contact lens treated with Eb were increased due to increase in the hydrophilic group such as O-C=O and OH group on the contact lens surface which could be produced by possible reaction between carbon and oxygen during the Eb irradiation. All of the lenses showed the high optical transmittance above 90%. In this case of B/Es, TES, Ti contact lens, the optical transmittance decreased about 5% with increasing Eb dose in the wavelength of UV-B region. The contact lens modified by Eb irradiation could improve the physical properties of the contact lens such as water content and oxygen transmissibility

  5. SLC status and SLAC [Stanford Linear Accelerator Center] future plans

    International Nuclear Information System (INIS)

    Richter, B.

    1989-08-01

    In this presentation, I shall discuss the linear collider program at the Stanford Linear Accelerator Center as it is now, and as we hope to see it evolve over the next few years. Of greatest interest to the high energy accelerator physics community gathered here is the development of the linear collider concept, and so I shall concentrate most of this paper on a discussion of the present status and future evolution of the SLC. I will also briefly discuss the research and development program that we are carrying out aimed at the realization of the next generation of high-energy linear colliders. SLAC had a major colliding-beam storage-ring program as well, including present rings and design studies on future high-luminosity projects, but time constraints preclude a discussion of them. 8 figs., 3 tabs

  6. Short wavelength FELs using the SLAC linac

    International Nuclear Information System (INIS)

    Winick, H.; Bane, K.; Boyce, R.

    1993-08-01

    Recent technological developments have opened the possibility to construct a device which we call a Linac Coherent Light Source (LCLS); a fourth generation light source, with brightness, coherence, and peak power far exceeding other sources. Operating on the principle of the free electron laser (FEL), the LCLS would extend the range of FEL operation to much aborter wavelength than the 240 mn that has so far been reached. We report the results of studies of the use of the SLAC linac to drive an LCLS at wavelengths from about 3-100 nm initially and possibly even shorter wavelengths in the future. Lasing would be achieved in a single pass of a low emittance, high peak current, high energy electron beam through a long undulator. Most present FELs use an optical cavity to build up the intensity of the light to achieve lasing action in a low gain oscillator configuration. By eliminating the optical cavity, which is difficult to make at short wavelengths, laser action can be extended to shorter wavelengths by Self-Amplified-Spontaneous-Emission (SASE), or by harmonic generation from a longer wavelength seed laser. Short wavelength, single pass lasers have been extensively studied at several laboratories and at recent workshops

  7. Properties of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    International Nuclear Information System (INIS)

    Konvalina, I.; Muellerova, I.

    2011-01-01

    The cathode lens is an electron optical element in an emission electron microscope accelerating electrons from the sample, which serves as a source for a beam of electrons. Special application consists in using the cathode lens first for retardation of an illuminating electron beam and then for acceleration of reflected as well as secondary electrons, made in the directly imaging low energy electron microscope or in its scanning version discussed here. In order to form a real image, the cathode lens has to be combined with a focusing magnetic lens or a focusing immersion-magnetic lens, as used for objective lenses of some commercial scanning electron microscopes. These two alternatives are compared with regards to their optical properties, in particular with respect to predicted aberration coefficients and the spot size, as well as the optimum angular aperture of the primary beam. The important role of the final aperture size on the image resolution is also presented.

  8. Peltier ac calorimeter

    OpenAIRE

    Jung, D. H.; Moon, I. K.; Jeong, Y. H.

    2001-01-01

    A new ac calorimeter, utilizing the Peltier effect of a thermocouple junction as an ac power source, is described. This Peltier ac calorimeter allows to measure the absolute value of heat capacity of small solid samples with sub-milligrams of mass. The calorimeter can also be used as a dynamic one with a dynamic range of several decades at low frequencies.

  9. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, M.A.; Foreman, L.R.

    1997-07-08

    This invention describes a method for fabricating an intraocular lens made from clear Teflon{trademark}, Mylar{trademark}, or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube. 13 figs.

  10. Digital model for harmonic interactions in AC/DC/AC systems

    Energy Technology Data Exchange (ETDEWEB)

    Guarini, A P; Rangel, R D; Pilotto, L A.S.; Pinto, R J; Passos, Junior, R [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)

    1994-12-31

    The main purpose of this paper is to present a model for calculation of HVdc converter harmonics taking into account the influence of the harmonic interactions between the ac systems in dc link transmissions. The ideas and methodologies used in the model development take into account the dc current ripple and ac voltage distortion in the ac systems. The theory of switching functions is applied to contemplate for the frequency conversions between the ac and dc sides, in an iterative process. It is possible then to obtain, even in balanced situations, non-characteristic harmonics that are produced by frequencies originated in the other terminal, which can be significant in a strongly coupled system, such as back-to-back configuration. (author) 9 refs., 3 figs.

  11. 21 CFR 886.1375 - Bagolini lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bagolini lens. 886.1375 Section 886.1375 Food and... OPHTHALMIC DEVICES Diagnostic Devices § 886.1375 Bagolini lens. (a) Identification. A Bagolini lens is a device that consists of a plane lens containing almost imperceptible striations that do not obscure...

  12. Facility for Advanced Accelerator Experimental Tests at SLAC (FACET) Conceptual Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Amann, J.; Bane, K.; /SLAC

    2009-10-30

    This Conceptual Design Report (CDR) describes the design of FACET. It will be updated to stay current with the developing design of the facility. This CDR begins as the baseline conceptual design and will evolve into an 'as-built' manual for the completed facility. The Executive Summary, Chapter 1, gives an introduction to the FACET project and describes the salient features of its design. Chapter 2 gives an overview of FACET. It describes the general parameters of the machine and the basic approaches to implementation. The FACET project does not include the implementation of specific scientific experiments either for plasma wake-field acceleration for other applications. Nonetheless, enough work has been done to define potential experiments to assure that the facility can meet the requirements of the experimental community. Chapter 3, Scientific Case, describes the planned plasma wakefield and other experiments. Chapter 4, Technical Description of FACET, describes the parameters and design of all technical systems of FACET. FACET uses the first two thirds of the existing SLAC linac to accelerate the beam to about 20GeV, and compress it with the aid of two chicanes, located in Sector 10 and Sector 20. The Sector 20 area will include a focusing system, the generic experimental area and the beam dump. Chapter 5, Management of Scientific Program, describes the management of the scientific program at FACET. Chapter 6, Environment, Safety and Health and Quality Assurance, describes the existing programs at SLAC and their application to the FACET project. It includes a preliminary analysis of safety hazards and the planned mitigation. Chapter 7, Work Breakdown Structure, describes the structure used for developing the cost estimates, which will also be used to manage the project. The chapter defines the scope of work of each element down to level 3.

  13. Facility for Advanced Accelerator Experimental Tests at SLAC (FACET) Conceptual Design Report

    International Nuclear Information System (INIS)

    Amann, J.; Bane, K.

    2009-01-01

    This Conceptual Design Report (CDR) describes the design of FACET. It will be updated to stay current with the developing design of the facility. This CDR begins as the baseline conceptual design and will evolve into an 'as-built' manual for the completed facility. The Executive Summary, Chapter 1, gives an introduction to the FACET project and describes the salient features of its design. Chapter 2 gives an overview of FACET. It describes the general parameters of the machine and the basic approaches to implementation. The FACET project does not include the implementation of specific scientific experiments either for plasma wake-field acceleration for other applications. Nonetheless, enough work has been done to define potential experiments to assure that the facility can meet the requirements of the experimental community. Chapter 3, Scientific Case, describes the planned plasma wakefield and other experiments. Chapter 4, Technical Description of FACET, describes the parameters and design of all technical systems of FACET. FACET uses the first two thirds of the existing SLAC linac to accelerate the beam to about 20GeV, and compress it with the aid of two chicanes, located in Sector 10 and Sector 20. The Sector 20 area will include a focusing system, the generic experimental area and the beam dump. Chapter 5, Management of Scientific Program, describes the management of the scientific program at FACET. Chapter 6, Environment, Safety and Health and Quality Assurance, describes the existing programs at SLAC and their application to the FACET project. It includes a preliminary analysis of safety hazards and the planned mitigation. Chapter 7, Work Breakdown Structure, describes the structure used for developing the cost estimates, which will also be used to manage the project. The chapter defines the scope of work of each element down to level 3.

  14. Setup and Calibration of SLAC's Peripheral Monitoring Stations

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, C.

    2004-09-03

    The goals of this project were to troubleshoot, repair, calibrate, and establish documentation regarding SLAC's (Stanford Linear Accelerator Center's) PMS (Peripheral Monitoring Station) system. The PMS system consists of seven PMSs that continuously monitor skyshine (neutron and photon) radiation levels in SLAC's environment. Each PMS consists of a boron trifluoride (BF{sub 3}) neutron detector (model RS-P1-0802-104 or NW-G-20-12) and a Geiger Moeller (GM) gamma ray detector (model TGM N107 or LND 719) together with their respective electronics. Electronics for each detector are housed in Nuclear Instrument Modules (NIMs) and are plugged into a NIM bin in the station. All communication lines from the stations to the Main Control Center (MCC) were tested prior to troubleshooting. To test communication with MCC, a pulse generator (Systron Donner model 100C) was connected to each channel in the PMS and data at MCC was checked for consistency. If MCC displayed no data, the communication cables to MCC or the CAMAC (Computer Automated Measurement and Control) crates were in need of repair. If MCC did display data, then it was known that the communication lines were intact. All electronics from each station were brought into the lab for troubleshooting. Troubleshooting usually consisted of connecting an oscilloscope or scaler (Ortec model 871 or 775) at different points in the circuit of each detector to record simulated pulses produced by a pulse generator; the input and output pulses were compared to establish the location of any problems in the circuit. Once any problems were isolated, repairs were done accordingly. The detectors and electronics were then calibrated in the field using radioactive sources. Calibration is a process that determines the response of the detector. Detector response is defined as the ratio of the number of counts per minute interpreted by the detector to the amount of dose equivalent rate (in mrem per hour, either calculated

  15. The lens and cataracts.

    Science.gov (United States)

    Matthews, Andrew G

    2004-08-01

    It is conservatively estimated that some form of lens opacity is present in 5% to 7% of horses with otherwise clinically normal eyes.These opacities can range from small epicapsular remnants of the fetal vasculature to dense and extensive cataract. A cataract is defined technically as any opacity or alteration in the optical homogeneity of the lens involving one or more of the following: anterior epithelium, capsule, cortex, or nucleus. In the horse, cataracts rarely involve the entire lens structure (ie, complete cataracts) and are more usually localized to one anatomic landmark or sector of the lens. Complete cataracts are invariably associated with overt and significant visual disability. Focal or incomplete cataracts alone seldom cause any apparent visual dysfunction in affected horses,however.

  16. A Tribute to Len Barton

    Science.gov (United States)

    Tomlinson, Sally

    2010-01-01

    This article constitutes a short personal tribute to Len Barton in honour of his work and our collegial relationship going back over 30 years. It covers how Len saw his intellectual project of providing critical sociological and political perspectives on special education, disability and inclusion, and his own radical political perspectives. Len's…

  17. Photosensitized oxidation in the ocular lens: evidence for photosensitizers endogenous to the human lens

    International Nuclear Information System (INIS)

    Zigler, J.S. Jr.; Goosey, J.D.

    1981-01-01

    Numerous investigators have attempted to associate near UV light exposure with various changes which occur to lens crystallins during aging and cataractogenesis. Recently it was shown that in vitro singlet oxygen mediated oxidation of lens crystallins produces effects very similar to those documented for crystallins from old or cataractous lenses and it was suggested that near UV photodynamic effects may play a major role in vivo in aging in the human lens. It has now been shown that certain oxidation products of tryptophan which have been identified in human lens can act as near UV photosensitizers, producing singlet oxygen. The insoluble protein fraction from human cataracts was shown to have the capacity to act as a photosensitizer. An age-related increase in photosensitizing capacity was also demonstrated in the soluble crystallins from human lens. These findings are discussed with respect to development of pigmented nuclear cataracts. (author)

  18. A course in lens design

    CERN Document Server

    Velzel, Chris

    2014-01-01

    A Course in Lens Design is an instruction in the design of image-forming optical systems. It teaches how a satisfactory design can be obtained in a straightforward way. Theory is limited to a minimum, and used to support the practical design work. The book introduces geometrical optics, optical instruments and aberrations. It gives a description of the process of lens design and of the strategies used in this process. Half of its content is devoted to the design of sixteen types of lenses, described in detail from beginning to end. This book is different from most other books on lens design because it stresses the importance of the initial phases of the design process: (paraxial) lay-out and (thin-lens) pre-design. The argument for this change of accent is that in these phases much information can be obtained about the properties of the lens to be designed. This information can be used in later phases of the design. This makes A Course in Lens Design a useful self-study book, and a suitable basis for an intro...

  19. Development of Fresnel lens for improvement of rear visibility; Shikai kojo Fresnel lens no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, K; Sanada, C; Tsukino, M [Nissan Motor Co. Ltd., Tokyo (Japan)

    1997-10-01

    Fresnel lenses have been widely used to increase the visual field around vehicles for drivers. However, internal reflection in these lenses has been an obstacle in producing dear images. This internal glow is generated by incident light from an unexpected direction reflecting on the non-lens surface or radiating from the non-lens surface of the Fresnel lens. The cause of internal glow has been made dear combining louver film with the lens. The newly developed technology removes obstacles in producing dear images by reducing internal glow. 7 figs.

  20. Single-bunch beam loading on the SLAC two-mile accelerator

    International Nuclear Information System (INIS)

    Koontz, R.F.

    1976-05-01

    The experiments described were initially prompted by interest in the radiation loss of relativistic electron rings passing through periodic structures. Later the same experiments became relevant to the theory of energy loss of electrons in large storage rings. In both of these cases energy loss to the higher order modes of the respective structures could seriously limit their effective operation. In these experiments, single bunches of electrons with intensities up to 7 x 10 8 electrons per bunch are accelerated through the SLAC three-kilometer accelerator, and their energy spectra are analyzed. Early experiments over a wide energy range (900 MeV to 19 GeV) demonstrated that the energy loss was proportional to the total charge in the bunch but was independent of beam energy. The average energy loss of a single bunch normalized to 10 9 electrons was initially measured to be 38 MeV

  1. ACS Zero Point Verification

    Science.gov (United States)

    Dolphin, Andrew

    2005-07-01

    The uncertainties in the photometric zero points create a fundamental limit to the accuracy of photometry. The current state of the ACS calibration is surprisingly poor, with zero point uncertainties of 0.03 magnitudes. The reason for this is that the ACS calibrations are based primarily on semi-emprical synthetic zero points and observations of fields too crowded for accurate ground-based photometry. I propose to remedy this problem by obtaining ACS images of the omega Cen standard field with all nine broadband ACS/WFC filters. This will permit the direct determination of the ACS zero points by comparison with excellent ground-based photometry, and should reduce their uncertainties to less than 0.01 magnitudes. A second benefit is that it will facilitate the comparison of the WFPC2 and ACS photometric systems, which will be important as WFPC2 is phased out and ACS becomes HST's primary imager. Finally, three of the filters will be repeated from my Cycle 12 observations, allowing for a measurement of any change in sensitivity.

  2. Vitrectorhexis and lens aspiration with posterior chamber intraocular lens implantation in spherophakia.

    Science.gov (United States)

    Al-Haddad, Christiane; Khatib, Lama

    2012-07-01

    We describe a technique that uses the vitrector to perform successful lens aspiration and posterior chamber intraocular lens (IOL) implantation in children with spherophakia and anterior lens subluxation. After an anterior chamber maintainer is placed, the ocutome is introduced through a limbal incision to perform a circular vitrectorhexis to avoid excessive manipulation of the unstable lens followed by gentle cortex aspiration. A foldable IOL is injected into the sulcus (3-piece IOL) or bag (1-piece IOL) if the capsule is sufficiently stable. Through a pars plana incision, the ocutome is then used to perform a posterior capsulotomy to prevent late posterior capsule opacification. In our patient, sulcus IOL placement was more stable than in-the-bag placement. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  3. Pentacam Scheimpflug quantitative imaging of the crystalline lens and intraocular lens.

    Science.gov (United States)

    Rosales, Patricia; Marcos, Susana

    2009-05-01

    To implement geometrical and optical distortion correction methods for anterior segment Scheimpflug images obtained with a commercially available system (Pentacam, Oculus Optikgeräte GmbH). Ray tracing algorithms were implemented to obtain corrected ocular surface geometry from the original images captured by the Pentacam's CCD camera. As details of the optical layout were not fully provided by the manufacturer, an iterative procedure (based on imaging of calibrated spheres) was developed to estimate the camera lens specifications. The correction procedure was tested on Scheimpflug images of a physical water cell model eye (with polymethylmethacrylate cornea and a commercial IOL of known dimensions) and of a normal human eye previously measured with a corrected optical and geometrical distortion Scheimpflug camera (Topcon SL-45 [Topcon Medical Systems Inc] from the Vrije University, Amsterdam, Holland). Uncorrected Scheimpflug images show flatter surfaces and thinner lenses than in reality. The application of geometrical and optical distortion correction algorithms improves the accuracy of the estimated anterior lens radii of curvature by 30% to 40% and of the estimated posterior lens by 50% to 100%. The average error in the retrieved radii was 0.37 and 0.46 mm for the anterior and posterior lens radii of curvature, respectively, and 0.048 mm for lens thickness. The Pentacam Scheimpflug system can be used to obtain quantitative information on the geometry of the crystalline lens, provided that geometrical and optical distortion correction algorithms are applied, within the accuracy of state-of-the art phakometry and biometry. The techniques could improve with exact knowledge of the technical specifications of the instrument, improved edge detection algorithms, consideration of aspheric and non-rotationally symmetrical surfaces, and introduction of a crystalline gradient index.

  4. Luneburg lens in silicon photonics.

    Science.gov (United States)

    Di Falco, Andrea; Kehr, Susanne C; Leonhardt, Ulf

    2011-03-14

    The Luneburg lens is an aberration-free lens that focuses light from all directions equally well. We fabricated and tested a Luneburg lens in silicon photonics. Such fully-integrated lenses may become the building blocks of compact Fourier optics on chips. Furthermore, our fabrication technique is sufficiently versatile for making perfect imaging devices on silicon platforms.

  5. Crystalline lens and refractive development.

    Science.gov (United States)

    Iribarren, Rafael

    2015-07-01

    Individual refractive errors usually change along lifespan. Most children are hyperopic in early life. This hyperopia is usually lost during growth years, leading to emmetropia in adults, but myopia also develops in children during school years or during early adult life. Those subjects who remain emmetropic are prone to have hyperopic shifts in middle life. And even later, at older ages, myopic shifts are developed with nuclear cataract. The eye grows from 15 mm in premature newborns to approximately 24 mm in early adult years, but, in most cases, refractions are maintained stable in a clustered distribution. This growth in axial length would represent a refractive change of more than 40 diopters, which is compensated by changes in corneal and lens powers. The process which maintains the balance between the ocular components of refraction during growth is still under study. As the lens power cannot be measured in vivo, but can only be calculated based on the other ocular components, there have not been many studies of lens power in humans. Yet, recent studies have confirmed that the lens loses power during growth in children, and that hyperopic and myopic shifts in adulthood may be also produced by changes in the lens. These studies in children and adults give a picture of the changing power of the lens along lifespan. Other recent studies about the growth of the lens and the complexity of its internal structure give clues about how these changes in lens power are produced along life. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Status of the SLAC/LBL/LLNL B-Factory and the BaBar detector

    International Nuclear Information System (INIS)

    Oddone, P.

    1994-08-01

    The primary motivation of the Asymmetric B-Factory is the study of CP violation. The decay of B mesons and, in particular, the decay of neutral B mesons, offers the possibility of determining conclusively whether CP violation is part and parcel of the Standard Model with three generations of quarks and leptons. Alternatively, the authors may discover that CP violation lies outside the present framework. In this paper the authors briefly describe the physics reach of the SLAC/LBL/LLNL Asymmetric B-Factory, the progress on the machine design and construction, the progress on the detector design, and the schedule to complete both projects

  7. The optical design of the spin manipulation system for the SLAC Linear Collider

    International Nuclear Information System (INIS)

    Fieguth, T.H.

    1989-03-01

    The optical design of the beam transport lines between the SLAC Linac and the electron damping ring and the design of part of the Linac lattice itself will be modified to accommodate three superconducting solenoids for the purpose of manipulating the polarization of the electron beam. In order to allow arbitrary orientation of the polarization vector, this design will be capable of compensating the fields of two independent solenoids for arbitrary strengths ranging to 7.0 T-m. The method of dealing with the coupling of the betatron functions and the method of handling both the electron and positron beams in the common region are discussed. 8 refs., 5 figs

  8. Modern lens antennas for communications engineering

    CERN Document Server

    Thornton, John

    2012-01-01

    The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

  9. Changes in monkey crystalline lens spherical aberration during simulated accommodation in a lens stretcher.

    Science.gov (United States)

    Maceo Heilman, Bianca; Manns, Fabrice; de Castro, Alberto; Durkee, Heather; Arrieta, Esdras; Marcos, Susana; Parel, Jean-Marie

    2015-02-10

    The purpose of this study was to quantify accommodation-induced changes in the spherical aberration of cynomolgus monkey lenses. Twenty-four lenses from 20 cynomolgus monkeys (Macaca fascicularis; 4.4-16.0 years of age; postmortem time 13.5 ± 13.0 hours) were mounted in a lens stretcher. Lens spherical aberration was measured in the unstretched (accommodated) and stretched (relaxed) states with a laser ray tracing system that delivered 51 equally spaced parallel rays along 1 meridian of the lens over the central 6-mm optical zone. A camera mounted below the lens was used to measure the ray height at multiple positions along the optical axis. For each entrance ray, the change in ray height with axial position was fitted with a third-order polynomial. The effective paraxial focal length and Zernike spherical aberration coefficients corresponding to a 6-mm pupil diameter were extracted from the fitted values. The unstretched lens power decreased with age from 59.3 ± 4.0 diopters (D) for young lenses to 45.7 ± 3.1 D for older lenses. The unstretched lens shifted toward less negative spherical aberration with age, from -6.3 ± 0.7 μm for young lenses to -5.0 ± 0.5 μm for older lenses. The power and spherical aberration of lenses in the stretched state were independent of age, with values of 33.5 ± 3.4 D and -2.6 ± 0.5 μm, respectively. Spherical aberration is negative in cynomolgus monkey lenses and becomes more negative with accommodation. These results are in good agreement with the predicted values using computational ray tracing in a lens model with a reconstructed gradient refractive index. The spherical aberration of the unstretched lens becomes less negative with age. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

  10. Symmetric lens with extended depth of focus

    OpenAIRE

    Cho, Sung Nae

    2008-01-01

    The lens surface profile is derived based on the instantaneous focal length versus the lens radius data. The lens design based on instantaneous focal length versus the lens radius data has many useful applications in software assisted image focusing technology.

  11. [Congenital lens subluxation: visual acuity outcomes and intraocular lens postoperative position].

    Science.gov (United States)

    Arraes, Caroline; Endriss, Daniela; Lobato, Francisco; Arraes, João; Ventura, Marcelo

    2010-01-01

    To evaluate the visual acuity outcomes and to investigate the intraocular lens (IOL) and endocapsular ring positions with ultrasound biomicroscopy in 17 eyes of 10 patients with congenital lens subluxation who underwent the same surgical technique, by the same surgeon. The study was performed in the ''Hospital de Olhos de Pernambuco'' and ''Fundação Altino Ventura''. The surgical technique consisted of phacoaspiration with implant of endocapsular ring and intraocular lens with one loop haptic amputated. The age varied from 7 to 22 years. Data on visual acuity (VA) before and after surgery, surgery follow-up period, and complications were analyzed. All patients underwent ultrasound biomicroscopy. The mean follow-up period was 2.8 years. There was a VA improvement in 17 (100%) eyes: in 12 eyes (70.6%) the visual acuity was better than 20/40; 4 (23.5%) ranged from 20/40 to 20/100, and 1 (5.9%) had visual acuity worse than 20/100, however better than the preoperative visual acuity. The posterior capsular opacification occurred in 10 eyes (58.9%). Ultrasound biomicroscopy showed that all IOL were partially decentralized, however without surpassing the pupil border limit. Endocapsular ring position was correct and there was a good capsular support in all cases. The evaluated surgical treatment provided good intraocular lens and endocapsular ring position, with VA improvement Thus, this technique is a viable, effective and safe option for the visual rehabilitation of patients with congenital lens subluxation.

  12. The influence of end of day silicone hydrogel daily disposable contact lens fit on ocular comfort, physiology and lens wettability.

    Science.gov (United States)

    Wolffsohn, James; Hall, Lee; Mroczkowska, Stephanie; Hunt, Olivia A; Bilkhu, Paramdeep; Drew, Tom; Sheppard, Amy

    2015-10-01

    To quantify the end-of-day silicone-hydrogel daily disposable contact lens fit and its influence of on ocular comfort, physiology and lens wettability. Thirty-nine subjects (22.1±3.5 years) were randomised to wear each of 3 silicone-hydrogel daily-disposable contact lenses (narafilcon A, delefilcon A and filcon II 3), bilaterally, for one week. Lens fit was assessed objectively using a digital video slit-lamp at 8, 12 and 16h after lens insertion. Hyperaemia, non-invasive tear break-up time, tear meniscus height and comfort were also evaluated at these timepoints, while corneal and conjunctival staining were assessed on lens removal. Lens fit assessments were not different between brands (P>0.05), with the exception of the movement at blink where narafilcon A was more mobile. Overall, lag reduced but push-up speed increased from 8 to 12h (P0.05). Movement-on-blink was unaffected by wear-time (F=0.403, P=0.670). A more mobile lens fit with one brand did not indicate that person would have a more mobile fit with another brand (r=-0.06 to 0.63). Lens fit was not correlated with comfort, ocular physiology or lens wettability (P>0.01). Among the lenses tested, objective lens fit changed between 8h and 12h of lens wear. The weak correlation in individual lens fit between brands indicates that fit is dependent on more than ocular shape. Consequently, substitution of a different lens brand with similar parameters will not necessarily provide comparable lens fit. Copyright © 2015 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  13. Constraints on cosmological models from strong gravitational lensing systems

    International Nuclear Information System (INIS)

    Cao, Shuo; Pan, Yu; Zhu, Zong-Hong; Biesiada, Marek; Godlowski, Wlodzimierz

    2012-01-01

    Strong lensing has developed into an important astrophysical tool for probing both cosmology and galaxies (their structure, formation, and evolution). Using the gravitational lensing theory and cluster mass distribution model, we try to collect a relatively complete observational data concerning the Hubble constant independent ratio between two angular diameter distances D ds /D s from various large systematic gravitational lens surveys and lensing by galaxy clusters combined with X-ray observations, and check the possibility to use it in the future as complementary to other cosmological probes. On one hand, strongly gravitationally lensed quasar-galaxy systems create such a new opportunity by combining stellar kinematics (central velocity dispersion measurements) with lensing geometry (Einstein radius determination from position of images). We apply such a method to a combined gravitational lens data set including 70 data points from Sloan Lens ACS (SLACS) and Lens Structure and Dynamics survey (LSD). On the other hand, a new sample of 10 lensing galaxy clusters with redshifts ranging from 0.1 to 0.6 carefully selected from strong gravitational lensing systems with both X-ray satellite observations and optical giant luminous arcs, is also used to constrain three dark energy models (ΛCDM, constant w and CPL) under a flat universe assumption. For the full sample (n = 80) and the restricted sample (n = 46) including 36 two-image lenses and 10 strong lensing arcs, we obtain relatively good fitting values of basic cosmological parameters, which generally agree with the results already known in the literature. This results encourages further development of this method and its use on larger samples obtained in the future

  14. Constraints on cosmological models from strong gravitational lensing systems

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shuo; Pan, Yu; Zhu, Zong-Hong [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Biesiada, Marek [Department of Astrophysics and Cosmology, Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Godlowski, Wlodzimierz, E-mail: baodingcaoshuo@163.com, E-mail: panyu@cqupt.edu.cn, E-mail: biesiada@us.edu.pl, E-mail: godlowski@uni.opole.pl, E-mail: zhuzh@bnu.edu.cn [Institute of Physics, Opole University, Oleska 48, 45-052 Opole (Poland)

    2012-03-01

    Strong lensing has developed into an important astrophysical tool for probing both cosmology and galaxies (their structure, formation, and evolution). Using the gravitational lensing theory and cluster mass distribution model, we try to collect a relatively complete observational data concerning the Hubble constant independent ratio between two angular diameter distances D{sub ds}/D{sub s} from various large systematic gravitational lens surveys and lensing by galaxy clusters combined with X-ray observations, and check the possibility to use it in the future as complementary to other cosmological probes. On one hand, strongly gravitationally lensed quasar-galaxy systems create such a new opportunity by combining stellar kinematics (central velocity dispersion measurements) with lensing geometry (Einstein radius determination from position of images). We apply such a method to a combined gravitational lens data set including 70 data points from Sloan Lens ACS (SLACS) and Lens Structure and Dynamics survey (LSD). On the other hand, a new sample of 10 lensing galaxy clusters with redshifts ranging from 0.1 to 0.6 carefully selected from strong gravitational lensing systems with both X-ray satellite observations and optical giant luminous arcs, is also used to constrain three dark energy models (ΛCDM, constant w and CPL) under a flat universe assumption. For the full sample (n = 80) and the restricted sample (n = 46) including 36 two-image lenses and 10 strong lensing arcs, we obtain relatively good fitting values of basic cosmological parameters, which generally agree with the results already known in the literature. This results encourages further development of this method and its use on larger samples obtained in the future.

  15. Low Offset AC Correlator.

    Science.gov (United States)

    This patent describes a low offset AC correlator avoids DC offset and low frequency noise by frequency operating the correlation signal so that low...noise, low level AC amplification can be substituted for DC amplification. Subsequently, the high level AC signal is demodulated to a DC level. (Author)

  16. AC power supply systems

    International Nuclear Information System (INIS)

    Law, H.

    1987-01-01

    An ac power supply system includes a rectifier fed by a normal ac supply, and an inverter connected to the rectifier by a dc link, the inverter being effective to invert the dc output of the receiver at a required frequency to provide an ac output. A dc backup power supply of lower voltage than the normal dc output of the rectifier is connected across the dc link such that the ac output of the rectifier is derived from the backup supply if the voltage of the output of the inverter falls below that of the backup supply. The dc backup power may be derived from a backup ac supply. Use in pumping coolant in nuclear reactor is envisaged. (author)

  17. Refractive lens exchange with a multifocal diffractive aspheric intraocular lens

    Directory of Open Access Journals (Sweden)

    Teresa Ferrer-Blasco

    2012-06-01

    Full Text Available PURPOSE: To evaluate the safety, efficacy and predictability after refractive lens exchange with multifocal diffractive aspheric intraocular lens implantation. METHODS: Sixty eyes of 30 patients underwent bilateral implantation with AcrySof® ReSTOR® SN6AD3 intraocular lens with +4.00 D near addition. Patients were divided into myopic and hyperopic groups. Monocular best corrected visual acuity at distance and near and monocular uncorrected visual acuity at distance and near were measured before and 6 months postoperatively. RESULTS: After surgery, uncorrected visual acuity was 0.08 ± 0.15 and 0.11 ± 0.14 logMAR for the myopic and hyperopic groups, respectively (50% and 46.67% of patients had an uncorrected visual acuity of 20/20 or better in the myopic and hyperopic groups, respectively. The safety and efficacy indexes were 1.05 and 0.88 for the myopic and 1.01 and 0.86 for the hyperopic groups at distance vision. Within the myopic group, 20 eyes remained unchanged after the surgery, and 3 gained >2 lines of best corrected visual acuity. For the hyperopic group, 2 eyes lost 2 lines of best corrected visual acuity, 21 did not change, and 3 eyes gained 2 lines. At near vision, the safety and efficacy indexes were 1.23 and 1.17 for the myopic and 1.16 and 1.13 for the hyperopic groups. Best corrected near visual acuity improved after surgery in both groups (from 0.10 logMAR to 0.01 logMAR in the myopic group, and from 0.10 logMAR to 0.04 logMAR in the hyperopic group. CONCLUSIONS: The ReSTOR® SN6AD3 intraocular lens in refractive lens exchange demonstrated good safety, efficacy, and predictability in correcting high ametropia and presbyopia.

  18. 21 CFR 886.5844 - Prescription spectacle lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prescription spectacle lens. 886.5844 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5844 Prescription spectacle lens. (a) Identification. A prescription spectacle lens is a glass or plastic device that is a lens intended to be worn by...

  19. ACS Photometric Zero Point Verification

    Science.gov (United States)

    Dolphin, Andrew

    2003-07-01

    The uncertainties in the photometric zero points create a fundamental limit to the accuracy of photometry. The current state of the ACS calibration is surprisingly poor, with zero point uncertainties of 0.03 magnitudes in the Johnson filters. The reason for this is that ACS observations of excellent ground-based standard fields, such as the omega Cen field used for WFPC2 calibrations, have not been obtained. Instead, the ACS photometric calibrations are based primarily on semi-emprical synthetic zero points and observations of fields too crowded for accurate ground-based photometry. I propose to remedy this problem by obtaining ACS broadband images of the omega Cen standard field with both the WFC and HRC. This will permit the direct determination of the ACS transformations, and is expected to double the accuracy to which the ACS zero points are known. A second benefit is that it will facilitate the comparison of the WFPC2 and ACS photometric systems, which will be important as WFPC2 is phased out and ACS becomes HST's primary imager.

  20. SLAC/DESY International Workshop on Interactions of Intense Sub-Picosecond X-Rays with Matter, Stanford, CA, January 23-24, 1997

    International Nuclear Information System (INIS)

    Tatchyn, Roman

    1998-01-01

    This is the proceedings volume of the 1997 SLAC/DESY International Workshop on Interactions of Intense Sub-picosecond X-Ray Pulses with Matter. The workshop theme evolved out of design and R and D studies, undertaken at SLAC, DESY, and elsewhere [1,2], of the new class of linac-driven X-Ray Free Electron Lasers (XRFELs) operating with photocathode-based, low-emittance electron beams in the Self-Amplified Spontaneous Emission (SASE) regime [3]. It can be noted that, following the conclusion of the workshop, funded design study reports on R and D facilities based on these novel sources have been completed and published by both laboratories [4,5]. Topical significance was imparted to the workshop agenda by a series of prior workshops organized to explore scientific and technological applications of linac driven XRFELs [6,7,8,9]. These served to highlight underlying concerns regarding the potential loading effects of the highly intense radiation pulses from this new class of light source on the instrumentation, samples, and experimental phenomena being considered. The primary objectives of the workshop were: (a) to provide tutorial overviews of existing theoretical, numerical, and experimental techniques in the study of interactions of intense, ultra-short radiation pulses with matter, and of their applicability to the parameter regimes of the SLAC and DESY XRFELs; (b) to discuss practical optics and instrumentation issues related to peak and average power density loading; (c) to identify and explore novel concepts and design approaches, with an emphasis on optical instrumentation and experimental physics; (d) to formulate independent or collaborative R and D programs and activities in the areas of theory, numerical simulation, and experimental physics relevant to the linac-driven XRFEL parameter regime

  1. Plasma Lens for Muon and Neutrino Beams

    International Nuclear Information System (INIS)

    Kahn, S.A.; Korenev, S.; Bishai, M.; Diwan, M.; Gallardo, J.C.; Hershcovitch, A.; Johnson, B.M.

    2008-01-01

    The plasma lens is examined as an alternate to focusing horns and solenoids for use in a neutrino or muon beam facility. The plasma lens concept is based on a combined high-energy lens/target configuration. The current is fed at electrodes located upstream and downstream from the target where pion capturing is needed. The current flows primarily in the plasma, which has a lower resistivity than the target. A second plasma lens section, with an additional current feed, follows the target to provide shaping of the plasma for optimum focusing. The plasma lens is immersed in an additional solenoid magnetic field to facilitate the plasma stability. The geometry of the plasma is shaped to provide optimal pion capture. Simulations of this plasma lens system have shown a 25% higher neutrino production than the horn system. Plasma lenses have the additional advantage of negligible pion absorption and scattering by the lens material and reduced neutrino contamination during anti-neutrino running. Results of particle simulations using plasma lens will be presented

  2. Lens decenter and tilt measurement by interferogram

    Science.gov (United States)

    Hung, Min-Wei; Wu, Wen-Hong; Huang, Kuo-Cheng

    2009-11-01

    For the recent years, the vigorous development of the electro-optic industry, particularly the digital camera and the cellular phone camera, has placed a larger and larger demand for the optical devices. Among the optical lens, the aspherical optical lens plays the key component because the aspherical lens may provide better imaging quality then the spherical lens does. For the manufacturing reason, the aspherical lens is prone to a decenter or tilt issue with respect to the optical axes of its two surfaces. To measure decenter and tile error specifically would help to obviate the deficient lens, but most of the present measuring method can't provide this function. This paper proposed a new method to specifically measure the decenter and tile of lens by observing the interferogram of each surface. And the corresponding measuring instrument, which contains interferometer and motion stages, was introduced as well.

  3. Clinical study of foldable intraocular lens secondary implantation after lens-vitrectomy in residual capsular with traumatic eyes

    Directory of Open Access Journals (Sweden)

    Ru-Fa Meng

    2015-07-01

    Full Text Available AIM: To investigate the operation methods and clinical effects of foldable intraocular lens secondary implantation after lens-vitrectomy in residual capsular with traumatic eyes.METHODS: During January 2012 to January 2014, foldable intraocular lens was implanted on 47 cases following lens-vitrectomy in residual capsular with traumatic eyes 3~6mo. Follow-up period was 6~12mo, averaged(8.21±2.63mo. RESULTS:All of 47 eyes had successful operation at one time, and position deviation was not appeared. The naked vision of the last postoperative follow-up was(0.44±0.19. Compared with best corrected visual acuity(0.41±0.23, and There was no significant difference between visual acuity of preoperative and last follow-up period(t=0.879, P=0.342. No severe complication was found. CONCLUSION: Secondary implantation of foldable intraocular lens is a safe and reliable method for correcting ametropia after lens-vitrectomy in residual capsular with traumatic eyes.

  4. 21 CFR 886.3600 - Intraocular lens.

    Science.gov (United States)

    2010-04-01

    ... DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3600 Intraocular lens. (a) Identification. An intraocular lens is a device made of materials such as glass or plastic intended to be implanted to replace the natural lens of an eye. (b) Classification. Class III. (c) Date PMA or notice of completion of a...

  5. Developing the Regulatory Utility of the Exposome: Mapping Exposures for Risk Assessment through Lifestage Exposome Snapshots (LEnS).

    Science.gov (United States)

    Shaffer, Rachel M; Smith, Marissa N; Faustman, Elaine M

    2017-08-07

    Exposome-related efforts aim to document the totality of human exposures across the lifecourse. This field has advanced rapidly in recent years but lacks practical application to risk assessment, particularly for children's health. Our objective was to apply the exposome to children's health risk assessment by introducing the concept of Lifestage Exposome Snapshots (LEnS). Case studies are presented to illustrate the value of the framework. The LEnS framework encourages organization of exposome studies based on windows of susceptibility for particular target organ systems. Such analyses will provide information regarding cumulative impacts during specific critical periods of the life course. A logical extension of this framework is that regulatory standards should analyze exposure information by target organ, rather than for a single chemical only or multiple chemicals grouped solely by mechanism of action. The LEnS concept is a practical refinement to the exposome that accounts for total exposures during particular windows of susceptibility in target organ systems. Application of the LEnS framework in risk assessment and regulation will improve protection of children's health by enhancing protection of sensitive developing organ systems that are critical for lifelong health and well-being. https://doi.org/10.1289/EHP1250.

  6. Impact of lens case hygiene guidelines on contact lens case contamination.

    Science.gov (United States)

    Wu, Yvonne T; Teng, Yuu Juan; Nicholas, Mary; Harmis, Najat; Zhu, Hua; Willcox, Mark D P; Stapleton, Fiona

    2011-10-01

    Lens case contamination is a risk factor for microbial keratitis. The effectiveness of manufacturers' lens case cleaning guidelines in limiting microbial contamination has not been evaluated in vivo. This study compared the effectiveness of manufacturers' guidelines and an alternative cleaning regimen. A randomized cross-over clinical trial with two phases (n = 40) was performed. Participants used the lens types of their choice in conjunction with the provided multipurpose solution (containing polyhexamethylene biguanide) for daily wear. In the manufacturers' guideline phase, cases were rinsed with multipurpose solution and air dried. In the alternative regimen phase, cases were rubbed, rinsed with solution, tissue wiped, and air-dried face down. The duration of each phase was 1 month. Lens cases were collected at the end of each phase for microbiological investigation. The levels of microbial contamination were compared, and compliance to both regimens was assessed. The case contamination rate was 82% (32/39) in the manufacturers' guideline group, compared with 72% (28/39) in the alternative regimen group. There were significantly fewer (p = 0.004) colony forming units (CFU) of bacteria from cases used by following the alternative regimen (CFU range of 0 to 10, and median of 12 CFU per well) compared with that of the manufacturer's guidelines (CFU range of 0 to 10, and median of 28 CFU per well). The compliance level between both guidelines was not significantly different (p > 0.05). The alternative guidelines are more effective in eliminating microbial contamination from lens cases than that of the current manufacturer's guideline. Simply incorporating rubbing and tissue-wiping steps in daily case hygiene reduces viable organism contamination.

  7. 21 CFR 886.1400 - Maddox lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Maddox lens. 886.1400 Section 886.1400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1400 Maddox lens. (a) Identification. A Maddox lens is a device...

  8. Intracapsular lens extraction for the treatment of pupillary block glaucoma associated with anterior subluxation of the crystalline lens.

    Science.gov (United States)

    Kim, Yong Joon; Ha, Seung Joo

    2013-01-01

    To report a case of pupillary block glaucoma associated with spontaneous crystalline lens subluxation into the anterior chamber in a 34-year-old man. Dry vitrectomy was performed for securing enough retrolental space, and an intracapsular lens extraction was then performed via a corneolimbal incision. Additional endothelial cell damage was avoided with an injection of viscoelastics and gentle extraction of the crystalline lens. After deepening of the anterior chamber, scleral fixation of the intraocular lens was performed with an ab externo technique. Two months after the operation, a well-fixated intraocular lens was observed and intraocular pressure was stable. The postoperative corneal astigmatism was -3.5 dpt, and the patient had a best-corrected visual acuity of 20/25. Postoperative complications included decreased endothelial cell count and sector iris paralysis near the incision site. An anteriorly subluxated crystalline lens can cause pupillary block glaucoma in healthy young adults. To prevent intraoperative complications, intracapsular lens extraction with dry vitrectomy can be a good surgical option. The endothelial cell density should be closely monitored after surgery.

  9. The Spin Structure Function of the Proton from SLAC Experiment E155

    Energy Technology Data Exchange (ETDEWEB)

    McKee, P

    2004-02-17

    Experiment E155 at the Stanford Linear Accelerator Center (SLAC) measured the longitudinal and transverse deep inelastic structure functions of the proton and deuteron using a polarized, 48.3 GeV electron beam and solid polarized targets of ammonia ({sup 15}NH{sub 3}) for proton measurements and lithium deuteride ({sup 6}Li{sup 2}H) for deuteron measurements. Three electromagnetic spectrometers at angles of 2.75{sup o}, 5.5{sup o}, and 10.5{sup o} measured the scattered electrons. This work presents an analysis of the longitudinal structure function of the proton, g{sub 1}{sup p}(x, Q{sup 2}). Included is a re-analysis of the proton target polarization data that for the first time corrects a problem encountered which altered those measurements.

  10. Production and decay of Z bosons at the SLC [SLAC Linear Collider

    International Nuclear Information System (INIS)

    Feldman, G.J.

    1989-12-01

    My lectures at Cargese covered the very first physics results from the SLAC Linear Collider (SLC). At the time of this writing (December 1989), it seems most sensible to present a review of the results that were presented at the school in an updated form. The organization of this report will be to give a brief introduction to linear colliders and the SLC, then to describe the MARK II detector, and finally to review the current status of the three major physics topics discussed at Cargese: the Z line shape, from which we deduce the Z mass and width, and the number of neutrino species, the partonic structure of hadronic decays and a measurement of α s , and searches for new quarks and leptons. 39 refs., 27 figs., 3 tabs

  11. Measurement of the Left-Right Asymmetry in Z0 Events at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Szumilo, A

    2004-01-05

    Recent results from the 1992 and 1993 left-right asymmetry cross section measurements at the Stanford Linear Accelerator Center are presented. Measurements made with SLAC running with a center-of-mass energy at the Z{sup 0}-pole (91.2 GeV) by the SLD detector and an average electron beam polarization of 22.4 {+-} 0.7% for 1992 and 62.6 {+-} 1.2% for 1993. The asymmetry measured was A{sub LR} = 0.100 {+-} 0.044 and A{sub LR} = 0.1656 {+-} 0.0073 for the 1992 and 1993 runs, respectively. This in turn allows them to calculate the weak mixing angle value of sin{sup 2} {theta}{sub W} = 0.2378 {+-} 0.0056 and sin{sup 2} {theta}{sub W} = 0.2288 {+-} 0.0009 for the two data sets.

  12. RELICS: Strong Lens Models for Five Galaxy Clusters from the Reionization Lensing Cluster Survey

    Science.gov (United States)

    Cerny, Catherine; Sharon, Keren; Andrade-Santos, Felipe; Avila, Roberto J.; Bradač, Maruša; Bradley, Larry D.; Carrasco, Daniela; Coe, Dan; Czakon, Nicole G.; Dawson, William A.; Frye, Brenda L.; Hoag, Austin; Huang, Kuang-Han; Johnson, Traci L.; Jones, Christine; Lam, Daniel; Lovisari, Lorenzo; Mainali, Ramesh; Oesch, Pascal A.; Ogaz, Sara; Past, Matthew; Paterno-Mahler, Rachel; Peterson, Avery; Riess, Adam G.; Rodney, Steven A.; Ryan, Russell E.; Salmon, Brett; Sendra-Server, Irene; Stark, Daniel P.; Strolger, Louis-Gregory; Trenti, Michele; Umetsu, Keiichi; Vulcani, Benedetta; Zitrin, Adi

    2018-06-01

    Strong gravitational lensing by galaxy clusters magnifies background galaxies, enhancing our ability to discover statistically significant samples of galaxies at {\\boldsymbol{z}}> 6, in order to constrain the high-redshift galaxy luminosity functions. Here, we present the first five lens models out of the Reionization Lensing Cluster Survey (RELICS) Hubble Treasury Program, based on new HST WFC3/IR and ACS imaging of the clusters RXC J0142.9+4438, Abell 2537, Abell 2163, RXC J2211.7–0349, and ACT-CLJ0102–49151. The derived lensing magnification is essential for estimating the intrinsic properties of high-redshift galaxy candidates, and properly accounting for the survey volume. We report on new spectroscopic redshifts of multiply imaged lensed galaxies behind these clusters, which are used as constraints, and detail our strategy to reduce systematic uncertainties due to lack of spectroscopic information. In addition, we quantify the uncertainty on the lensing magnification due to statistical and systematic errors related to the lens modeling process, and find that in all but one cluster, the magnification is constrained to better than 20% in at least 80% of the field of view, including statistical and systematic uncertainties. The five clusters presented in this paper span the range of masses and redshifts of the clusters in the RELICS program. We find that they exhibit similar strong lensing efficiencies to the clusters targeted by the Hubble Frontier Fields within the WFC3/IR field of view. Outputs of the lens models are made available to the community through the Mikulski Archive for Space Telescopes.

  13. Plasma Lens for Muon and Neutrino Beams

    Science.gov (United States)

    Kahn, Stephen; Korenev, Sergey; Bishai, Mary; Diwan, Milind; Gallardo, Juan; Hershcovitch, Ady; Johnson, Brant

    2008-04-01

    The plasma lens is examined as an alternate to focusing horns and solenoids for use in a neutrino or muon beam facility. The plasma lens concept is based on a combined high-current lens/target configuration. The current is fed at electrodes located upstream and downstream from the target where pion capturing is needed. The current flows primarily in the plasma, which has a lower resistivity than the target. A second plasma lens section, with an additional current feed, follows the target to provide shaping of the plasma stability. The geometry of the plasma is shaped to provide optimal pion capture. Simulations of this plasma lens system have shown a 25% higher neutrino production than the horn system. A plasma lens has additional advantage: larger axial current than horns, minimal neutrino contamination during antineutrino running, and negligible pion absorption or scattering. Results from particle simulations using a plasma lens will be presented.

  14. FLUIDIC AC AMPLIFIERS.

    Science.gov (United States)

    Several fluidic tuned AC Amplifiers were designed and tested. Interstage tuning and feedback designs are considered. Good results were obtained...corresponding Q’s as high as 12. Element designs and test results of one, two, and three stage amplifiers are presented. AC Modulated Carrier Systems

  15. Highlights of the SLD Physics Program at the SLAC Linear Collider

    International Nuclear Information System (INIS)

    Willocq, Stephane

    2001-01-01

    Starting in 1989, and continuing through the 1990s, high-energy physics witnessed a flowering of precision measurements in general and tests of the standard model in particular, led by e + e - collider experiments operating at the Z 0 resonance. Key contributions to this work came from the SLD collaboration at the SLAC Linear Collider. By exploiting the unique capabilities of this pioneering accelerator and the SLD detector, including a polarized electron beam, exceptionally small beam dimensions, and a CCD pixel vertex detector, SLD produced a broad array of electroweak, heavy-flavor, and QCD measurements. Many of these results are one of a kind or represent the world's standard in precision. This article reviews the highlights of the SLD physics program, with an eye toward associated advances in experimental technique, and the contribution of these measurements to our dramatically improved present understanding of the standard model and its possible extensions

  16. 78 FR 49318 - Availability of Draft Advisory Circular (AC) 90-106A and AC 20-167A

    Science.gov (United States)

    2013-08-13

    ...] Availability of Draft Advisory Circular (AC) 90-106A and AC 20- 167A AGENCY: Federal Aviation Administration... of draft Advisory Circular (AC) 90-106A, Enhanced Flight Vision Systems and draft AC 20- 167A... Federal holidays. FOR FURTHER INFORMATION CONTACT: For technical questions concerning draft AC 90-106A...

  17. [Representation and mathematical analysis of human crystalline lens].

    Science.gov (United States)

    Tălu, Stefan; Giovanzana, Stefano; Tălu, Mihai

    2011-01-01

    The surface of human crystalline lens can be described and analyzed using mathematical models based on parametric representations, used in biomechanical studies and 3D solid modeling of the lens. The mathematical models used in lens biomechanics allow the study and the behavior of crystalline lens on variables and complex dynamic loads. Also, the lens biomechanics has the potential to improve the results in the development of intraocular lenses and cataract surgery. The paper presents the most representative mathematical models currently used for the modeling of human crystalline lens, both optically and biomechanically.

  18. Deletion of the AcMNPV core gene ac109 results in budded virions that are non-infectious

    International Nuclear Information System (INIS)

    Fang Minggang; Nie, Yingchao; Theilmann, David A.

    2009-01-01

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac109 is a core gene and its function in the virus life cycle is unknown. To determine its role in the baculovirus life cycle, we used the AcMNPV bacmid system to generate an ac109 deletion virus (vAc 109KO ). Fluorescence and light microscopy showed that transfection of vAc 109KO results in a single-cell infection phenotype. Viral DNA replication is unaffected and the development of occlusion bodies in vAc 109KO -transfected cells evidenced progression to the very late phases of viral infection. Western blot and confocal immunofluorescence analysis showed that AC109 is expressed in the cytoplasm and nucleus throughout infection. In addition, AC109 is a structural protein as it was detected in both budded virus (BV) and occlusion derived virus in both the envelope and nucleocapsid fractions. Titration assays by qPCR and TCID 50 showed that vAc 109KO produced BV but the virions are non-infectious. The vAc 109KO BV were indistinguishable from the BV of repaired and wild type control viruses as determined by negative staining and electron microscopy.

  19. Development of a hardware-based AC microgrid for AC stability assessment

    Science.gov (United States)

    Swanson, Robert R.

    As more power electronic-based devices enable the development of high-bandwidth AC microgrids, the topic of microgrid power distribution stability has become of increased interest. Recently, researchers have proposed a relatively straightforward method to assess the stability of AC systems based upon the time-constants of sources, the net bus capacitance, and the rate limits of sources. In this research, a focus has been to develop a hardware test system to evaluate AC system stability. As a first step, a time domain model of a two converter microgrid was established in which a three phase inverter acts as a power source and an active rectifier serves as an adjustable constant power AC load. The constant power load can be utilized to create rapid power flow transients to the generating system. As a second step, the inverter and active rectifier were designed using a Smart Power Module IGBT for switching and an embedded microcontroller as a processor for algorithm implementation. The inverter and active rectifier were designed to operate simultaneously using a synchronization signal to ensure each respective local controller operates in a common reference frame. Finally, the physical system was created and initial testing performed to validate the hardware functionality as a variable amplitude and variable frequency AC system.

  20. [Intraocular lens implantation with one loop haptic amputated: a new propose to the subluxation lens surgical treatment].

    Science.gov (United States)

    Ventura, Marcelo; Endriss, Daniela

    2010-01-01

    To evaluate the postoperative results of congenital lens subluxation corrected by a new technique. Retrospective chart review of 21 eyes of 13 patients with no traumatic lens subluxation who underwent surgery in Altino Ventura Foundation from April, 1999 to April, 2004. The mean age was 8.7 +/- 5.4 years old, and the mean follow-up period was 21.5 +/- 19.3 months. Patients underwent phacoaspiration, endocapsular ring and intraocular lens (IOL) implantation. The implanted IOL had one loop haptic excised and was supported above the ring, inside the capsular bag promoting intraocular lens centralization. Visual acuity improvement was observed in all cases. There was a significant reduction of the spherical equivalent and spherical component comparing the pre and postoperative refraction (psubluxation surgical treatment, promoting lens centralization and postoperative visual acuity improvement.

  1. Role of Aquaporin 0 in lens biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Sindhu Kumari, S.; Gupta, Neha [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Shiels, Alan [Washington University School of Medicine, St. Louis, MO (United States); FitzGerald, Paul G. [Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA (United States); Menon, Anil G. [University of Cincinnati College of Medicine, Cincinnati, OH (United States); Mathias, Richard T. [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States)

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and

  2. Role of Aquaporin 0 in lens biomechanics

    International Nuclear Information System (INIS)

    Sindhu Kumari, S.; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G.; Menon, Anil G.; Mathias, Richard T.; Varadaraj, Kulandaiappan

    2015-01-01

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5 −/− ), AQP0 KO (heterozygous KO: AQP0 +/− ; homozygous KO: AQP0 −/− ; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0 +/− lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to

  3. Research and Development Toward a 4.5-1.5 Angstrom Linac Coherent Light Source (LCLS) at SLAC

    International Nuclear Information System (INIS)

    Tatchyn, R.; Arthur, J.; Baltay, M.

    1995-08-01

    In recent years significant studies have been initiated on the feasibility of utilizing a portion of the 3km S-band accelerator at SLAC to drive a short wavelength (4.5-1.5 A) Linac Coherent Light Source (LCLS), a Free Electron Laser (FEL) operating in the Self- Amplified Spontaneous Emission (SASE) regime. Electron beam requirements for single-pass saturation in a minimal time include: (1) a peak current in the 7 kA range, (2) a relative energy spread of <0.05%, and (3) a transverse emittance, ε[r-m], approximating the diffraction limit condition ε = λ / 4π, where lambda(m) is the output wavelength. Requirements on the insertion device include field error levels of 0.02% for keeping the electron bunch centered on and in phase with the amplified photons, and a focusing beta of 8 m/rad for inhibiting the dilution of its transverse density. Although much progress has been made in developing individual components and beam processing techniques necessary for LCLS operation down to approx. 20 A, a substantial amount of research and development is still required in a number of theoretical and experimental areas leading to the construction and operation of a 4.5-1.5 A LCLS. In this paper we report on a research and development program underway and in planning at SLAC for addressing critical questions in these areas

  4. AcEST: DK948593 [AcEST

    Lifescience Database Archive (English)

    Full Text Available DKLSHFNYVVDVLIPYPIHLEI 163 >sp|A4QKR2|MATK_CRUWA Maturase K OS=Crucihimalaya wallichii GN=matK PE=3 SV=2 Len..._LOBMA Maturase K OS=Lobularia maritima GN=matK PE... 32 2.3 sp|A4QKR2|MATK_CRUWA Maturase K OS=Crucihimal...aya wallichii GN=ma... 32 3.0 sp|Q9GF51|MATK_ARAHA Maturase K OS=Arabidopsis haller

  5. Algorithm design of liquid lens inspection system

    Science.gov (United States)

    Hsieh, Lu-Lin; Wang, Chun-Chieh

    2008-08-01

    In mobile lens domain, the glass lens is often to be applied in high-resolution requirement situation; but the glass zoom lens needs to be collocated with movable machinery and voice-coil motor, which usually arises some space limits in minimum design. In high level molding component technology development, the appearance of liquid lens has become the focus of mobile phone and digital camera companies. The liquid lens sets with solid optical lens and driving circuit has replaced the original components. As a result, the volume requirement is decreased to merely 50% of the original design. Besides, with the high focus adjusting speed, low energy requirement, high durability, and low-cost manufacturing process, the liquid lens shows advantages in the competitive market. In the past, authors only need to inspect the scrape defect made by external force for the glass lens. As to the liquid lens, authors need to inspect the state of four different structural layers due to the different design and structure. In this paper, authors apply machine vision and digital image processing technology to administer inspections in the particular layer according to the needs of users. According to our experiment results, the algorithm proposed can automatically delete non-focus background, extract the region of interest, find out and analyze the defects efficiently in the particular layer. In the future, authors will combine the algorithm of the system with automatic-focus technology to implement the inside inspection based on the product inspective demands.

  6. Bioinspired adaptive gradient refractive index distribution lens

    Science.gov (United States)

    Yin, Kezhen; Lai, Chuan-Yar; Wang, Jia; Ji, Shanzuo; Aldridge, James; Feng, Jingxing; Olah, Andrew; Baer, Eric; Ponting, Michael

    2018-02-01

    Inspired by the soft, deformable human eye lens, a synthetic polymer gradient refractive index distribution (GRIN) lens with an adaptive geometry and focal power has been demonstrated via multilayer coextrusion and thermoforming of nanolayered elastomeric polymer films. A set of 30 polymer nanolayered films comprised of two thermoplastic polyurethanes having a refractive index difference of 0.05 were coextruded via forced-assembly technique. The set of 30 nanolayered polymer films exhibited transmission near 90% with each film varying in refractive index by 0.0017. An adaptive GRIN lens was fabricated from a laminated stack of the variable refractive index films with a 0.05 spherical GRIN. This lens was subsequently deformed by mechanical ring compression of the lens. Variation in the optical properties of the deformable GRIN lens was determined, including 20% variation in focal length and reduced spherical aberration. These properties were measured and compared to simulated results by placido-cone topography and ANSYS methods. The demonstration of a solid-state, dynamic focal length, GRIN lens with improved aberration correction was discussed relative to the potential future use in implantable devices.

  7. Radiation dose to the lens and cataract formation

    International Nuclear Information System (INIS)

    Henk, J.M.; Whitelocke, R.A.F.; Warrington, A.P.; Bessell, E.M.

    1993-01-01

    The purpose of this work was to determine the radiation tolerance of the lens of the eye and the incidence of radiation-induced lens changes in patients treated by fractionated supervoltage radiation therapy for orbital tumors. Forty patients treated for orbital lymphoma and pseudotumor with tumor doses of 20--40 Gy were studied. The lens was partly shielded using lead cylinders in most cases. The dose to the germinative zone of the lens was estimated by measurements in a tissue equivalent phantom using both film densitometry and thermoluminescent dosimetry. Opthalmological examination was performed at 6 monthly intervals after treatment. The lead shield was found to reduce the dose to the germinative zone of the lens to between 36--50% of the tumor dose for Cobalt beam therapy, and to between 11--18% for 5 MeV x-rays. Consequently, the lens doses were in the range 4.5--30 Gy in 10--20 fractions. Lens opacities first appeared from between 3 and 9 years after irradiation. Impairment of visual acuity ensued in 74% of the patients who developed lens opacities. The incidence of lens changes was strongly dose-related. None was seen after doses of 5 Gy or lower, whereas doses of 16.5 Gy or higher were all followed by lens opacities which impaired visual acuity. The largest number of patients received a maximum lens dose of 15 Gy; in this group the actuarial incidence of lens opacities at 8 years was 57% with visual impairment in 38%. The adult lens can tolerate a total dose of 5 Gy during a fractionated course of supervoltage radiation therapy without showing any changes. Doses of 16.5 Gy or higher will almost invariably lead to visual impairment. The dose which causes a 50% probability of visual impairment is approximately 15 Gy. 10 refs., 4 figs., 1 tab

  8. Stretchable Binary Fresnel Lens for Focus Tuning

    NARCIS (Netherlands)

    Li, X.; Wei, L.; Poelma, R.H.; Vollebregt, S.; Wei, J.; Urbach, Paul; Sarro, P.M.; Zhang, G.Q.

    2016-01-01

    This paper presents a tuneable binary amplitude Fresnel lens produced by wafer-level microfabrication. The Fresnel lens is fabricated by encapsulating lithographically defined vertically aligned carbon nanotube (CNT) bundles inside a polydimethyl-siloxane (PDMS) layer. The composite lens material

  9. Single-bunch beam loading on the SLAC two-mile accelerator

    International Nuclear Information System (INIS)

    Koontz, R.F.

    1976-01-01

    The experiments described were initially prompted by interest in the radiation loss of relativistic electron rings passing through periodic structures. Later, the same experiments became relevant to the theory of energy loss of electrons in large storage rings. In both of these cases, energy loss to the higher order modes of the respective structures could seriously limit their effective operation as acceleration devices. In these experiments, single bunches of electrons with intensities up to 7 x 10 8 electrons per bunch are accelerated through the SLAC three-kilometer accelerator, and their energy spectra are analyzed. Early experiments over a wide energy range (900 MeV to 19 GeV) demonstrated that the energy loss was proportional to the total charge in the bunch but was independent of beam energy. The average energy loss of a single bunch normalized to 10 9 electrons was initially measured to be 38 MeV. The experiments, including much of the equipment development, are described and are compared with theoretical predictions made to date

  10. STATUS OF X-BAND STANDING WAVE STRUCTURE STUDIES AT SLAC

    International Nuclear Information System (INIS)

    Dolgashev, Valery A.

    2003-01-01

    The linacs proposed for the Next Linear Collider (NLC) and Japanese Linear Collider (JLC) would contain several thousand X-Band accelerator structures that would operate at a loaded gradient of 50 MV/m. An extensive experimental and theoretical program is underway at SLAC, FNAL and KEK to develop structures that reliably operate at this gradient. The development of standing wave structures is a part of this program. The properties of standing wave structures allow them to operate at the loaded gradient in contrast to traveling wave structures that need conditioning to the unloaded gradient (65 MV/m for NLC/JLC). The gradients in the standing structures tested thus far have been limited by input coupler breakdowns. The behavior of these breakdowns is consistent with a model of pulsed heating due to high magnetic fields. New input couplers have been designed to reduce maximum magnetic fields. This paper discusses design considerations related to high power performance, wakefield suppression and results of high power tests of prototype standing wave structures

  11. Performance of the PEP-II B-Factory Collider at SLAC

    International Nuclear Information System (INIS)

    Seeman, J.; Browne, M.; Cai, Y.; Colocho, W.; Decker, F.J.; Donald, M.H.; Ecklund, S.; Erickson, R.A.; Fisher, A.S.; Fox, J.D.; Heifets, S.A.; Iverson, R.H.; Kulikov, A.; Li, N.; Novokhatski, A.; Ross, M.C.; Schuh, P.; Smith, T.J.; Sonnad, K.G.; Stanek, M.; Sullivan, M.K.

    2006-01-01

    PEP-II is an e + e - asymmetric B-Factory Collider located at SLAC operating at the Upsilon 4S resonance (3.1 GeV x 9 GeV). It has reached a luminosity of 9.21 x 10 33 /cm 2 /s and has delivered an integrated luminosity of 710 pb -1 in one day. PEP-II has delivered, over the past six years, an integrated luminosity to the BaBar detector of over 262 fb -1 . PEP-II operates in continuous injection mode for both beams boosting the integrated luminosity. The peak positron current has reached 2.45 A in 1588 bunches. Steady progress is being made in reaching higher luminosity. The goal over the next several years is to reach a luminosity of 2.1 x 10 34 /cm 2 /s. The accelerator physics issues being addressed in PEP-II to reach this goal include the electron cloud instability, beam-beam effects, parasitic beam-beam effects, high RF beam loading, shorter bunches, lower β* y interaction region operation, and coupling control. Figure 1 shows the PEP-II tunnel

  12. 21 CFR 886.1390 - Flexible diagnostic Fresnel lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Flexible diagnostic Fresnel lens. 886.1390 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1390 Flexible diagnostic Fresnel lens. (a) Identification. A flexible diagnostic Fresnel lens is a device that is a very thin lens which has...

  13. A catoptric lens

    International Nuclear Information System (INIS)

    Rambauske, W.R.

    1973-01-01

    The invention relates to a catoptric lens for combining energies transmitted by several sources such as lasers; said lens comprising mirrors, the reflective surfaces of which have their focuses spaced from a common axis of symmetry. By means of these reflecting surfaces, which are generated by the nutation of portions of quadratic conics about the axis of symmetry, it is possible to focus the energy emmited by several lasers at the focus of the exit-mirror reflecting surface. This can be applied to thermonuclear fusion [fr

  14. Estimating BrAC from transdermal alcohol concentration data using the BrAC estimator software program.

    Science.gov (United States)

    Luczak, Susan E; Rosen, I Gary

    2014-08-01

    Transdermal alcohol sensor (TAS) devices have the potential to allow researchers and clinicians to unobtrusively collect naturalistic drinking data for weeks at a time, but the transdermal alcohol concentration (TAC) data these devices produce do not consistently correspond with breath alcohol concentration (BrAC) data. We present and test the BrAC Estimator software, a program designed to produce individualized estimates of BrAC from TAC data by fitting mathematical models to a specific person wearing a specific TAS device. Two TAS devices were worn simultaneously by 1 participant for 18 days. The trial began with a laboratory alcohol session to calibrate the model and was followed by a field trial with 10 drinking episodes. Model parameter estimates and fit indices were compared across drinking episodes to examine the calibration phase of the software. Software-generated estimates of peak BrAC, time of peak BrAC, and area under the BrAC curve were compared with breath analyzer data to examine the estimation phase of the software. In this single-subject design with breath analyzer peak BrAC scores ranging from 0.013 to 0.057, the software created consistent models for the 2 TAS devices, despite differences in raw TAC data, and was able to compensate for the attenuation of peak BrAC and latency of the time of peak BrAC that are typically observed in TAC data. This software program represents an important initial step for making it possible for non mathematician researchers and clinicians to obtain estimates of BrAC from TAC data in naturalistic drinking environments. Future research with more participants and greater variation in alcohol consumption levels and patterns, as well as examination of gain scheduling calibration procedures and nonlinear models of diffusion, will help to determine how precise these software models can become. Copyright © 2014 by the Research Society on Alcoholism.

  15. Highlights of the SLD Physics Program at the SLAC Linear Collider

    Energy Technology Data Exchange (ETDEWEB)

    Willocq, Stephane

    2001-09-07

    Starting in 1989, and continuing through the 1990s, high-energy physics witnessed a flowering of precision measurements in general and tests of the standard model in particular, led by e{sup +}e{sup -} collider experiments operating at the Z{sup 0} resonance. Key contributions to this work came from the SLD collaboration at the SLAC Linear Collider. By exploiting the unique capabilities of this pioneering accelerator and the SLD detector, including a polarized electron beam, exceptionally small beam dimensions, and a CCD pixel vertex detector, SLD produced a broad array of electroweak, heavy-flavor, and QCD measurements. Many of these results are one of a kind or represent the world's standard in precision. This article reviews the highlights of the SLD physics program, with an eye toward associated advances in experimental technique, and the contribution of these measurements to our dramatically improved present understanding of the standard model and its possible extensions.

  16. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic Hruby fundus lens. 886.1395 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1395 Diagnostic Hruby fundus lens. (a) Identification. A diagnostic Hruby fundus lens is a device that is a 55 diopter lens intended for use in the...

  17. The Role of Aquaporins in Ocular Lens Homeostasis

    Science.gov (United States)

    Schey, Kevin L.; Petrova, Rosica S.; Gletten, Romell B.; Donaldson, Paul J.

    2017-01-01

    Aquaporins (AQPs), by playing essential roles in the maintenance of ocular lens homeostasis, contribute to the establishment and maintenance of the overall optical properties of the lens over many decades of life. Three aquaporins, AQP0, AQP1 and AQP5, each with distinctly different functional properties, are abundantly and differentially expressed in the different regions of the ocular lens. Furthermore, the diversity of AQP functionality is increased in the absence of protein turnover by age-related modifications to lens AQPs that are proposed to alter AQP function in the different regions of the lens. These regional differences in AQP functionality are proposed to contribute to the generation and directionality of the lens internal microcirculation; a system of circulating ionic and fluid fluxes that delivers nutrients to and removes wastes from the lens faster than could be achieved by passive diffusion alone. In this review, we present how regional differences in lens AQP isoforms potentially contribute to this microcirculation system by highlighting current areas of investigation and emphasizing areas where future work is required. PMID:29231874

  18. 21 CFR 886.1380 - Diagnostic condensing lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic condensing lens. 886.1380 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1380 Diagnostic condensing lens. (a) Identification. A diagnostic condensing lens is a device used in binocular indirect ophthalmoscopy (a procedure...

  19. Bacterial transmission from lens storage cases to contact lenses-Effects of lens care solutions and silver impregnation of cases.

    Science.gov (United States)

    Vermeltfoort, Pit B J; Hooymans, Johanna M M; Busscher, Henk J; van der Mei, Henny C

    2008-10-01

    The killing efficacies of multipurpose lens care solutions on planktonic and biofilm bacteria grown in polypropylene contact lens storage cases with and without silver impregnation and effects on bacterial transmission from storage cases to silicone hydrogel contact lenses were investigated. For transmission studies, biofilms of Staphylococcus aureus 835 or Pseudomonas aeruginosa no. 3 were grown on lens storage cases and incubated with a contact lens in different multipurpose lens care solutions (Opti-Free(R)Express(R), ReNu(R) MultiPlus(R), and SoloCare Aquatrade mark) or 0.9% NaCl. In addition, planktonic bacteria were directly suspended in multipurpose solutions and their killing efficacies were determined. The numbers of transmitted live and dead bacteria on the lenses were measured using a combination of plate counting and fluorescence microscopy. The highest killing efficacies were shown by Opti-Free(R) Express(R) for planktonic as well as for biofilm bacteria. Silver impregnation of lens cases in combination with the prescribed solution increased the killing efficacy for P. aeruginosa in biofilms, whereas effects for S. aureus were minor. Lowest numbers of live and dead bacteria were transmitted to a lens in Opti-Free(R) Express(R) multipurpose solution, with no significant differences between lens types and no effects of silver impregnation. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008. (c) 2008 Wiley Periodicals, Inc.

  20. Progress report on the SLAC Linear Collider

    International Nuclear Information System (INIS)

    Kozanecki, W.

    1987-11-01

    In this paper we report on the status of the SLAC Linear Collider (SLC), the prototype of a new generation of colliding beam accelerators. This novel type of machine holds the potential of extending electron-positron colliding beam studies to center-of-mass (c.m.) energies far in excess of what is economically achievable with colliding beam storage rings. If the technical challenges posed by linear colliders are solvable at a reasonable cost, this new approach would provide an attractive alternative to electron-positron rings, where, because of rapidly rising synchrotron radiation losses, the cost and size of the ring increases with the square of the c.m. energy. In addition to its role as a test vehicle for the linear collider principle, the SLC aims at providing an abundant source of Z 0 decays to high energy physics experiments. Accordingly, two major detectors, the upgraded Mark II, now installed on the SLC beam line, and the state-of-the-art SLD, currently under construction, are preparing to probe the Standard Model at the Z 0 pole. The SLC project was originally funded in 1983. Since the completion of construction, we have been commissioning the machine to bring it up to a performance level adequate for starting the high energy physics program. In the remainder of this paper, we will discuss the status, problems and performance of the major subsystems of the SLC. We will conclude with a brief outline of the physics program, and of the planned enhancements to the capabilities of the machine. 26 refs., 7 figs

  1. Iris reconstruction combined with iris-claw intraocular lens implantation for the management of iris-lens injured patients.

    Science.gov (United States)

    Hu, Shufang; Wang, Mingling; Xiao, Tianlin; Zhao, Zhenquan

    2016-03-01

    To study the efficiency and safety of iris reconstruction combined with iris-claw intraocular lens (IOL) implantation in the patients with iris-lens injuries. Retrospective, noncomparable consecutive case series study. Eleven patients (11 eyes) following iris-lens injuries underwent iris reconstructions combined with iris-claw IOL implantations. Clinical data, such as cause and time of injury, visual acuity (VA), iris and lens injuries, surgical intervention, follow-up period, corneal endothelial cell count, and optical coherence tomography, were collected. Uncorrected VA (UCVA) in all injured eyes before combined surgery was equal to or iris returned to its natural round shape or smaller pupil, and the iris-claw IOLs in the 11 eyes were well-positioned on the anterior surface of reconstructed iris. No complications occurred in those patients. Iris reconstruction combined with iris-claw IOL implantation is a safe and efficient procedure for an eye with iris-lens injury in the absence of capsular support.

  2. Wide-range tunable magnetic lens for tabletop electron microscope

    International Nuclear Information System (INIS)

    Chang, Wei-Yu; Chen, Fu-Rong

    2016-01-01

    A tabletop scanning electron microscope (SEM) utilizes permanent magnets as condenser lenses to minimize its size, but this sacrifices the tunability of condenser lenses such that a tabletop system can only be operated with a fixed accelerating voltage. In contrast, the traditional condenser lens utilizes an electromagnetic coil to adjust the optical properties, but the size of the electromagnetic lens is inevitably larger. Here, we propose a tunable condenser lens for a tabletop SEM that uses a combination of permanent magnets and electromagnetic coils. The overall dimensions of the newly designed lens are the same as the original permanent magnet lens, but the new lens allows the tabletop SEM to be operated at different accelerating voltages between 1 kV and 15 kV. - Highlights: • A compact condenser lens combines both permanent magnet and coils. • A tunable lens is designed to keep the same focal point for voltage 1 to 15 kV. • A miniature tunable lens which can directly fit into tabletop SEM.

  3. Wide-range tunable magnetic lens for tabletop electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Wei-Yu; Chen, Fu-Rong, E-mail: fchen1@me.com

    2016-12-15

    A tabletop scanning electron microscope (SEM) utilizes permanent magnets as condenser lenses to minimize its size, but this sacrifices the tunability of condenser lenses such that a tabletop system can only be operated with a fixed accelerating voltage. In contrast, the traditional condenser lens utilizes an electromagnetic coil to adjust the optical properties, but the size of the electromagnetic lens is inevitably larger. Here, we propose a tunable condenser lens for a tabletop SEM that uses a combination of permanent magnets and electromagnetic coils. The overall dimensions of the newly designed lens are the same as the original permanent magnet lens, but the new lens allows the tabletop SEM to be operated at different accelerating voltages between 1 kV and 15 kV. - Highlights: • A compact condenser lens combines both permanent magnet and coils. • A tunable lens is designed to keep the same focal point for voltage 1 to 15 kV. • A miniature tunable lens which can directly fit into tabletop SEM.

  4. 21 CFR 886.1420 - Ophthalmic lens gauge.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic lens gauge. 886.1420 Section 886.1420...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1420 Ophthalmic lens gauge. (a) Identification. An ophthalmic lens gauge is a calibrated device intended to manually measure the curvature of a...

  5. RHIC spin flipper AC dipole controller

    Energy Technology Data Exchange (ETDEWEB)

    Oddo, P.; Bai, M.; Dawson, C.; Gassner, D.; Harvey, M.; Hayes, T.; Mernick, K.; Minty, M.; Roser, T.; Severino, F.; Smith, K.

    2011-03-28

    The RHIC Spin Flipper's five high-Q AC dipoles which are driven by a swept frequency waveform require precise control of phase and amplitude during the sweep. This control is achieved using FPGA based feedback controllers. Multiple feedback loops are used to and dynamically tune the magnets. The current implementation and results will be presented. Work on a new spin flipper for RHIC (Relativistic Heavy Ion Collider) incorporating multiple dynamically tuned high-Q AC-dipoles has been developed for RHIC spin-physics experiments. A spin flipper is needed to cancel systematic errors by reversing the spin direction of the two colliding beams multiple times during a store. The spin flipper system consists of four DC-dipole magnets (spin rotators) and five AC-dipole magnets. Multiple AC-dipoles are needed to localize the driven coherent betatron oscillation inside the spin flipper. Operationally the AC-dipoles form two swept frequency bumps that minimize the effect of the AC-dipole dipoles outside of the spin flipper. Both AC bumps operate at the same frequency, but are phase shifted from each other. The AC-dipoles therefore require precise control over amplitude and phase making the implementation of the AC-dipole controller the central challenge.

  6. Adaptive mechanical-wetting lens actuated by ferrofluids

    Science.gov (United States)

    Cheng, Hui-Chuan; Xu, Su; Liu, Yifan; Levi, Shoshana; Wu, Shin-Tson

    2011-04-01

    We report an adaptive mechanical-wetting lens actuated by ferrofluids. The ferrofluids works like a piston to pump liquids in and out from the lens chamber, which in turn reshapes the lens curvature and changes the focal length. Both positive and negative lenses are demonstrated experimentally. The ferrofluid-actuated mechanical-wetting lens exhibits some attractive features, such as high resolution, fast response time, low power consumption, simple structure and electronic control, weak gravity effect, and low cost. Its potential applications in medical imaging, surveillance, and commercial electronics are foreseeable.

  7. Numerical studies on the ramped density plasma lens

    International Nuclear Information System (INIS)

    Williams, R.L.; Katsouleas, T.

    1992-01-01

    We consider the so-called adiabatic plasma lens when the plasma density is ramped too quickly to be considered adiabatic. The lens length can be much shorter in such a case, but the final spot size is shown to be larger by a factor of √1+α 2 than for a slowly ramped plasma lens with the same initial and final density (where α=-β'/2 is proportional to the plasma density gradient). We find that the final spot size is the same whether or not the Courant-Snyder parameters of the beam (α and β) are matched to the lens. However, matched beams allow the plasma density to be lower while unmatched beams allow the lens to be shorter (for the same α and for the same final to initial plasma density ratio). Finally, we find that a smaller spot size can be obtained for a given lens length and density ratio by starting at smaller α and increasing α along the lens

  8. LASL lens design procedure: simple, fast, precise, versatile

    International Nuclear Information System (INIS)

    Brixner, B.

    1978-11-01

    The Los Alamos Scientific Laboratory general-purpose lens design procedure optimizes specific lens prescriptions to obtain the smallest possible image spots and therefore near-spherical wave fronts of light converging on all images in the field of view. Optical image errors are analyzed in much the same way that they are measured on the optical bench. This lens design method is made possible by using the full capabilities of large electronic computers. First, the performance of the whole lens is sampled with many precisely traced skew rays. Next, lens performance is analyzed with spot diagrams generated by the many rays. Third, lens performance is optimized with a least squares system aimed at reducing all image errors to zero. This statistical approach to lens design uses skew rays and precisely measured ray deviations from ideal image points to achieve greater accuracy than was possible with the classical procedure, which is based on approximate expressions derived from simplified ray traces developed for pencil-and-paper calculations

  9. Measuring emittances and sigma matrices

    International Nuclear Information System (INIS)

    Rees, J.; Rivkin, L.

    1984-03-01

    The method used for measuring emittance at the SLAC Linac and the linear collider damping ring is described. The basis of the method is derived using one two-by-two matrix to specify the state of the input beam (sigma matrix) and another to describe the lens-drift transport system (R-matrix)

  10. High Dk piggyback contact lens system for contact lens-intolerant keratoconus patients.

    Science.gov (United States)

    Sengor, Tomris; Kurna, Sevda Aydin; Aki, Suat; Ozkurt, Yelda

    2011-01-01

    The aim of the study was to examine the clinical success of high Dk (oxygen permeability) piggyback contact lens (PBCL) systems for the correction of contact lens intolerant keratoconus patients. Sixteen patients (29 eyes) who were not able to wear gas-permeable rigid lenses were included in this study. Hyper Dk silicone hydrogel (oxygen transmissibility or Dk/t = 150 units) and fluorosilicone methacrylate copolymer (Dk/t = 100 units) lenses were chosen as the PBCL systems. The clinical examinations included visual acuity and corneal observation by biomicroscopy, keratometer reading, and fluorescein staining before and after fitting the PBCL system. INDICATIONS FOR USING PBCL SYSTEM WERE: lens stabilization and comfort, improving comfort, and adding protection to the cone. Visual acuities increased significantly in all of the patients compared with spectacles (P = 0). Improvement in visual acuity compared with rigid lenses alone was recorded in 89.7% of eyes and no alteration of the visual acuity was observed in 10.3% of the eyes. Wearing time of PBCL systems for most of the patients was limited time (mean 6 months, range 3-12 months); thereafter they tolerated rigid lenses alone except for 2 patients. The PBCL system is a safe and effective method to provide centering and corneal protection against mechanical trauma by the rigid lenses for keratoconus patients and may increase contact lens tolerance.

  11. Development of Powerhouse Using Fresnel lens

    Directory of Open Access Journals (Sweden)

    Al-Dohani Nawar Saif

    2018-01-01

    Full Text Available Solar energy is an alternative source of renewable energy. Sultanate of Oman government showed initiation on utilization of solar energy for domestic and industrial applications. Fresnel lens is one of the methods to collect maximum energy by gathering heat of the sun in the concentrated form (using solar collectors. Earlier research work discloses that Fresnel lens gave better result in terms of power output and produces lower heat loss as compared to linear –parabolic solar collectors. In this work, development of a proto Fresnel lens power house was made to generate electricity. The focused heat from Fresnel lens was used to heat the molten salt in a heat exchanger to produce the steam. The generated steam was used to rotate the steam engine coupled to a generator. In the current work, a maximum power of 30 W was produced. In addition, comparative study was carried out regarding solar salts and heat exchanger materials to understand the Fresnel powerhouse performance. Overall the present study gave valuable information regarding usage of Fresnel lens for electricity generation in Oman.

  12. Orbiting objective lens telescope system and method

    International Nuclear Information System (INIS)

    Crooks, J.W. Jr.

    1984-01-01

    A large objective lens is placed in a highly eccentric orbit about the earth. The orbit and orientation of the lens are carefully chosen so that it focuses light or other radiation from a preselected astronomical object into an image which slowly moves across the surface of the earth. A row of optical sensing units is located on the surface of the earth so that the image focused by the orbiting objective lens will travel substantially perpendicularly across the row during an observation. Output data generated from the sensing units may be multiplexed and fed to a real time processor which produces display signals. Each of the sensing units provides one scan line of the image being observed. The display signals are fed to a suitable display device which produces a picture of the preselected astronomical object. The objective lens may comprise a large flexible Fresnel zone plate or a flexible convex lens carried by a bicycle wheel-type supporting structure. The lens and supporting structure may be unfolded from compact cargo configurations and rotated after being placed into orbit

  13. Transient anterior subcapsular vacuolar change of the crystalline lens in patients after posterior chamber phakic intraocular lens implantation.

    Science.gov (United States)

    Chung, Jin Kwon; Shin, Jin Hee; Lee, Sung Jin

    2013-10-25

    We present two cases of transient vacuolar changes in the anterior subcapsular space of the crystalline lens in patients after posterior chamber phakic intraocular lens implantation. Implantable collamer lenses (ICL) were implanted in healthy myopic patients. Vacuolar changes developed just after the irrigating procedure through the narrow space between the ICL and the crystalline lens. Slit-lamp examinations and spectral domain optical coherence tomography showed bleb-like lesions in the anterior subcapsular space of one eye in each case, though the lesions gradually improved without visual deterioration. Consequently, the lesions turned into a few anterior subcapsular small faint opacities. Direct irrigation of the narrow space confined by the ICL and the crystalline lens is at risk for the development of vacuolar changes in the crystalline lens. The observed spontaneous reversal indicates that surgeons should not rush to surgical intervention but rather opt for close follow over several weeks.

  14. 3D Modeling Activity for Novel High Power Electron Guns at SLAC

    International Nuclear Information System (INIS)

    Krasnykh, Anatoly

    2003-01-01

    The next generation of powerful electronic devices requires new approaches to overcome the known limitations of existing tube technology. Multi-beam and sheet beam approaches are novel concepts for the high power microwave devices. Direct and indirect modeling methods are being developed at SLAC to meet the new requirements in the 3D modeling. The direct method of solving of Poisson's equations for the multi-beam and sheet beam guns is employed in the TOPAZ 3D tool. The combination of TOPAZ 2D and EGUN (in the beginning) with MAFIA 3D and MAGIC 3D (at the end) is used in an indirect method to model the high power electron guns. Both methods complement each other to get reliable representation of the beam trajectories. Several gun ideas are under consideration at the present time. The collected results of these simulations are discussed

  15. 3D Modeling Activity for Novel High Power Electron Guns at SLAC

    CERN Document Server

    Krasnykh, Anatoly K

    2003-01-01

    The next generation of powerful electronic devices requires new approaches to overcome the known limitations of existing tube technology. Multi-beam and sheet beam approaches are novel concepts for the high power microwave devices. Direct and indirect modeling methods are being developed at SLAC to meet the new requirements in the 3D modeling. The direct method of solving of Poisson's equations for the multi-beam and sheet beam guns is employed in the TOPAZ 3D tool. The combination of TOPAZ 2D and EGUN (in the beginning) with MAFIA 3D and MAGIC 3D (at the end) is used in an indirect method to model the high power electron guns. Both methods complement each other to get reliable representation of the beam trajectories. Several gun ideas are under consideration at the present time. The collected results of these simulations are discussed.

  16. Rat silicone hydrogel contact lens model: effects of high- versus low-Dk lens wear.

    Science.gov (United States)

    Zhang, Yunfan; Gabriel, Manal M; Mowrey-McKee, Mary F; Barrett, Ronald P; McClellan, Sharon; Hazlett, Linda D

    2008-11-01

    This study used a rat contact lens (CL) model to test if high- versus low-Dk lens wear caused changes in (1) conjunctival Langerhans cell (LC) number or location; (2) Bcl-2 expression; and (3) infection risk. Female, Lewis rats wore a high- or low-Dk CL continuously for 2 weeks. Afterward, corneas were harvested and processed for ADPase activity to identify LCs, for immunostaining and for real time-polymerase chain reaction. Contact lens-wearing rats also were challenged with Pseudomonas aeruginosa by placing a bacterial-soaked CL on the eye followed by topical delivery of bacteria. After 48 hrs, slit lamp examination and real time-polymerase chain reaction were used to evaluate the corneal response. Conjunctival LC were significantly increased after low- versus high-Dk CL wear (PDk lens wearing group. Bcl-2 mRNA levels were significantly decreased in low- versus high-Dk CL wearing rats, while Bax, FasL, caspase 3, and caspase 9 levels were unchanged. Immunostaining for Bcl-2 showed fewer positively stained epithelial cells in the low- versus high-Dk lens wearing group. After bacterial challenge, 30% of low- versus none of the high-Dk CL wearing corneas became infected and showed increased mRNA levels for several proinflammatory cytokines/chemokines, inducible nitric oxide synthase and matrix metalloproteinase-9. Low- versus high-Dk or non-CL wear led to an increased number of conjunctival LC, decreased Bcl-2 levels, and increased the risk of bacterial infection.

  17. Properties of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    Czech Academy of Sciences Publication Activity Database

    Konvalina, Ivo; Müllerová, Ilona

    2011-01-01

    Roč. 645, č. 1 (2011), s. 55-59 ISSN 0168-9002 R&D Projects: GA ČR GAP102/10/1410; GA AV ČR IAA100650902; GA MŠk ED0017/01/01 Institutional research plan: CEZ:AV0Z20650511 Keywords : cathode lens * compound objective lens * aberration coefficients * spot size * field calculations Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.207, year: 2011

  18. The AC photovoltaic module is here!

    Science.gov (United States)

    Strong, Steven J.; Wohlgemuth, John H.; Wills, Robert H.

    1997-02-01

    This paper describes the design, development, and performance results of a large-area photovoltaic module whose electrical output is ac power suitable for direct connection to the utility grid. The large-area ac PV module features a dedicated, integrally mounted, high-efficiency dc-to-ac power inverter with a nominal output of 250 watts (STC) at 120 Vac, 60 H, that is fully compatible with utility power. The module's output is connected directly to the building's conventional ac distribution system without need for any dc wiring, string combiners, dc ground-fault protection or additional power-conditioning equipment. With its advantages, the ac photovoltaic module promises to become a universal building block for use in all utility-interactive PV systems. This paper discusses AC Module design aspects and utility interface issues (including islanding).

  19. Freeform lens design for LED collimating illumination.

    Science.gov (United States)

    Chen, Jin-Jia; Wang, Te-Yuan; Huang, Kuang-Lung; Liu, Te-Shu; Tsai, Ming-Da; Lin, Chin-Tang

    2012-05-07

    We present a simple freeform lens design method for an application to LED collimating illumination. The method is derived from a basic geometric-optics analysis and construction approach. By using this method, a highly collimating lens with LED chip size of 1.0 mm × 1.0 mm and optical simulation efficiency of 86.5% under a view angle of ± 5 deg is constructed. To verify the practical performance of the lens, a prototype of the collimator lens is also made, and an optical efficiency of 90.3% with a beam angle of 4.75 deg is measured.

  20. The low-field permanent magnet electrostatic plasma lens

    International Nuclear Information System (INIS)

    Goncharov, A.; Gorshkov, V.; Maslov, V.; Zadorozhny, V.; Brown, I.

    2004-01-01

    We describe the status of ongoing research and development of the electrostatic plasma lens as used for the manipulation of high current broad beams of heavy ions of moderate energy. In some collaborative work at Lawrence Berkeley National Laboratory the lens was used to good effect for carrying out high dose ion implantation processing. In the process of this work a very narrow range of low magnetic field was found for which the ion-optical characteristics of the lens improved markedly. Subsequent theoretical analysis and computer modeling has led to an understanding of this phenomenon. These serendipitous results open up some attractive possibilities for the development of a new compact and low cost plasma lens based on permanent magnets rather than on current-driven field coils surrounding the lens volume. The development of this kind of lens, including both very low noise and minimal spherical aberration effects, may lead to a tool suitable for use in the injection beam lines of high current heavy ion linear accelerators. Here we briefly review the lens fundamentals, some characteristics of focusing heavy ion beams at low magnetic fields, and summarize recent theoretical and experimental developments, with emphasis on the relevance and suitability of the lens for accelerator injection application

  1. Precision lens assembly with alignment turning system

    Science.gov (United States)

    Ho, Cheng-Fang; Huang, Chien-Yao; Lin, Yi-Hao; Kuo, Hui-Jean; Kuo, Ching-Hsiang; Hsu, Wei-Yao; Chen, Fong-Zhi

    2017-10-01

    The poker chip assembly with high precision lens barrels is widely applied to ultra-high performance optical system. ITRC applies the poker chip assembly technology to the high numerical aperture objective lenses and lithography projection lenses because of its high efficiency assembly process. In order to achieve high precision lens cell for poker chip assembly, an alignment turning system (ATS) is developed. The ATS includes measurement, alignment and turning modules. The measurement module is equipped with a non-contact displacement sensor (NCDS) and an autocollimator (ACM). The NCDS and ACM are used to measure centration errors of the top and the bottom surface of a lens respectively; then the amount of adjustment of displacement and tilt with respect to the rotational axis of the turning machine for the alignment module can be determined. After measurement, alignment and turning processes on the ATS, the centration error of a lens cell with 200 mm in diameter can be controlled within 10 arcsec. Furthermore, a poker chip assembly lens cell with three sub-cells is demonstrated, each sub-cells are measured and accomplished with alignment and turning processes. The lens assembly test for five times by each three technicians; the average transmission centration error of assembly lens is 12.45 arcsec. The results show that ATS can achieve high assembly efficiency for precision optical systems.

  2. THE BOSS EMISSION-LINE LENS SURVEY. IV. SMOOTH LENS MODELS FOR THE BELLS GALLERY SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Yiping [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Bolton, Adam S.; Montero-Dorta, Antonio D.; Cornachione, Matthew A.; Zheng, Zheng; Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, UT 84112 (United States); Mao, Shude [Physics Department and Tsinghua Centre for Astrophysics, Tsinghua University, Beijing 100084 (China); Kochanek, Christopher S. [Department of Astronomy and Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Pérez-Fournon, Ismael; Marques-Chaves, Rui [Instituto de Astrofísica de Canarias, C/Vía Láctea, s/n, E-38205 San Cristóbal de La Laguna, Tenerife (Spain); Oguri, Masamune [Research Center for the Early Universe, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ménard, Brice, E-mail: yiping.shu@nao.cas.cn [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2016-12-20

    We present Hubble Space Telescope F606W-band imaging observations of 21 galaxy-Ly α emitter lens candidates in the Baryon Oscillation Spectroscopic Survey Emission-Line Lens Survey (BELLS) for the GALaxy-Ly α EmitteR sYstems (BELLS GALLERY) survey. Seventeen systems are confirmed to be definite lenses with unambiguous evidence of multiple imaging. The lenses are primarily massive early-type galaxies (ETGs) at redshifts of approximately 0.55, while the lensed sources are Ly α emitters (LAEs) at redshifts from two to three. Although most of the lens systems are well fit by smooth lens models consisting of singular isothermal ellipsoids in an external shear field, a thorough exploration of dark substructures in the lens galaxies is required. The Einstein radii of the BELLS GALLERY lenses are, on average, 60% larger than those of the BELLS lenses because of the much higher source redshifts. This will allow for a detailed investigation of the radius evolution of the mass profile in ETGs. With the aid of the average ∼13× lensing magnification, the LAEs are frequently resolved into individual star-forming knots with a wide range of properties. They have characteristic sizes from less than 100 pc to several kiloparsecs, rest-frame far-UV apparent AB magnitudes from 29.6 to 24.2, and typical projected separations of 500 pc to 2 kpc.

  3. Role of Aquaporin 0 in lens biomechanics.

    Science.gov (United States)

    Sindhu Kumari, S; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G; Menon, Anil G; Mathias, Richard T; Varadaraj, Kulandaiappan

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5(-/-)), AQP0 KO (heterozygous KO: AQP0(+/-); homozygous KO: AQP0(-/-); all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0(+/-) lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to confer

  4. Effect of infusion bottle height on lens power after lens refilling with and without a plug

    NARCIS (Netherlands)

    Koopmans, SA; Terwee, T; Haitjema, HJ; Kooijman, AC; Barkhof, J

    2003-01-01

    Purpose: To evaluate the influence of intraoperative infusion bottle height on the power of refilled pig lenses. Setting: Research Laboratory, Pharmacia Intraocular Lens Manufacturing Plant, Groningen, The Netherlands. Methods: This study comprised 2 groups of pig eyes. In 1 group, the lens was

  5. Chapter 03: Correct use of a hand lens

    Science.gov (United States)

    Alex Wiedenhoeft

    2011-01-01

    A hand lens is a powerful tool for the identification of wood, but like all tools it must be used correctly to take full advantage of its powers. The hand lens has two main parts, a lens that magnifies the object of interest (generally we use 10X or 14X lenses in wood identification; a 14X lens is recommended for use with this manual) and a housing to hold and protect...

  6. The neutron silicon lens. An update of the thermal neutron lens results

    International Nuclear Information System (INIS)

    Johnson, M.W.; Daymond, M.R.

    2001-01-01

    This paper introduces the concept of the Neutron Silicon Lens (NSL) and provides and update on the experimental results achieved to date. The NSL design is a cylindrical neutron lens based on the use of multiple neutron mirrors supported and separated by silicon wafers. Such lenses would have many applications in both the primary and scattered beams on neutron instruments, and would lead to immediate improvements where the sample to be illuminated is small, as in high pressure or engineering strain scanning instruments. (author)

  7. The neutron silicon lens. An update of the thermal neutron lens results

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, M.W.; Daymond, M.R. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom)

    2001-03-01

    This paper introduces the concept of the Neutron Silicon Lens (NSL) and provides and update on the experimental results achieved to date. The NSL design is a cylindrical neutron lens based on the use of multiple neutron mirrors supported and separated by silicon wafers. Such lenses would have many applications in both the primary and scattered beams on neutron instruments, and would lead to immediate improvements where the sample to be illuminated is small, as in high pressure or engineering strain scanning instruments. (author)

  8. Changes in the accommodation-convergence relationship after the Artisan phakic intraocular lens implantation for myopic patients.

    Science.gov (United States)

    Ryu, Ik Hee; Han, Jinu; Lee, Hyung Keun; Kim, Jin Kook; Han, Sueng-Han

    2014-04-01

    To evaluate the change of accommodation-convergence parameters after implantation of Artisan phakic intraocular lens (PIOL). Prospective study for the patients with the Artisan PIOL implantation was performed. A total of 37 patients (3 males and 34 females) enrolled the study. Preoperatively, convergence amplitude, the stimulus accommodative convergence per unit of accommodation (AC/A) ratio and the near point of convergence (NPC) were evaluated. After the Artisan PIOL implantation, the identical evaluations were repeated at 1 week, 1, 3, and 6 months after the surgery. Mean age was 24.3 ± 4.8 years old, and preoperative refractive error was -8.92 ± 4.13 diopters (D). After the implantation, mean refractive errors significantly decreased to within ±1.00 D, and noticeable complications were not found. The convergence amplitude and the stimulus AC/A ratio increased 1 month after the surgery, but progressively stabilized afterward to near preoperative values. NPC didn't show any significant change over follow-up period up to 6 months. These results regarding implantation of the Artisan PIOL revealed the increase of accommodation-convergence relationship within first 1 month after the surgery, but progressive stabilization was noted during follow-up periods.

  9. Levitação acústica

    OpenAIRE

    Andrade, Marco Aurélio Brizzotti; Pérez, Nicolás; Adamowski, Julio Cezar

    2015-01-01

    A levitação acústica pode ser uma ferramenta valiosa para auxiliar estudantes de graduação a aprender conceitos básicos de física, tais como movimento harmônico simples, ondas acústicas estacionárias, e energia potencial. Neste artigo, apresentamos o princípio de funcionamento de um levitador acústico e explicamos como aplicar as equações básicas da acústica para determinar a força de radiação acústica que atua numa esfera em uma onda estacionária. Acoustic levitation can be a valuable too...

  10. Spectral function calculation of angle wakes, wake moments, and misalignment wakes for the SLAC Damped Detuned Structures (DDS)

    International Nuclear Information System (INIS)

    Jones, R.M.; Miller, R.H.; Kroll, N.M.

    1997-05-01

    Transverse wake functions so far reported for the SLAC DDS have been limited to those caused by uniform offset of the drive beam in a straight perfectly aligned structure. The complete description of the betatron oscillations of wake coupled bunches requires an array of wake functions, referred to as moments. Modifications of these arrays induced by structure misalignments are also of interest. In this paper we express the array elements in terms of a spectral function array. Examples are given based upon DDS1

  11. Approaches to building single-stage AC/AC conversion switch-mode audio power amplifiers

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2004-01-01

    This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion...

  12. Introduction to AC machine design

    CERN Document Server

    Lipo, Thomas A

    2018-01-01

    AC electrical machine design is a key skill set for developing competitive electric motors and generators for applications in industry, aerospace, and defense. This book presents a thorough treatment of AC machine design, starting from basic electromagnetic principles and continuing through the various design aspects of an induction machine. Introduction to AC Machine Design includes one chapter each on the design of permanent magnet machines, synchronous machines, and thermal design. It also offers a basic treatment of the use of finite elements to compute the magnetic field within a machine without interfering with the initial comprehension of the core subject matter. Based on the author's notes, as well as after years of classroom instruction, Introduction to AC Machine Design: * Brings to light more advanced principles of machine design--not just the basic principles of AC and DC machine behavior * Introduces electrical machine design to neophytes while also being a resource for experienced designers * ...

  13. The RNA-binding protein Celf1 post-transcriptionally regulates p27Kip1 and Dnase2b to control fiber cell nuclear degradation in lens development.

    Directory of Open Access Journals (Sweden)

    Archana D Siddam

    2018-03-01

    Full Text Available Opacification of the ocular lens, termed cataract, is a common cause of blindness. To become transparent, lens fiber cells undergo degradation of their organelles, including their nuclei, presenting a fundamental question: does signaling/transcription sufficiently explain differentiation of cells progressing toward compromised transcriptional potential? We report that a conserved RNA-binding protein Celf1 post-transcriptionally controls key genes to regulate lens fiber cell differentiation. Celf1-targeted knockout mice and celf1-knockdown zebrafish and Xenopus morphants have severe eye defects/cataract. Celf1 spatiotemporally down-regulates the cyclin-dependent kinase (Cdk inhibitor p27Kip1 by interacting with its 5' UTR and mediating translation inhibition. Celf1 deficiency causes ectopic up-regulation of p21Cip1. Further, Celf1 directly binds to the mRNA of the nuclease Dnase2b to maintain its high levels. Together these events are necessary for Cdk1-mediated lamin A/C phosphorylation to initiate nuclear envelope breakdown and DNA degradation in fiber cells. Moreover, Celf1 controls alternative splicing of the membrane-organization factor beta-spectrin and regulates F-actin-crosslinking factor Actn2 mRNA levels, thereby controlling fiber cell morphology. Thus, we illustrate new Celf1-regulated molecular mechanisms in lens development, suggesting that post-transcriptional regulatory RNA-binding proteins have evolved conserved functions to control vertebrate oculogenesis.

  14. Computer modelling of bunch-by-bunch feedback for the SLAC B-factory design

    International Nuclear Information System (INIS)

    Briggs, D.; Fox, J.D.; Hosseini, W.; Klaisner, L.; Morton, P.; Pellegrin, J.L.; Thompson, K.A.; Lambertson, G.

    1991-05-01

    The SLAC B-factory design, with over 1600 high current bunches circulating in each ring, will require a feedback system to avoid coupled-bunch instabilities. A computer model of the storage ring, including the RF system, wave fields, synchrotron radiation loss, and the bunch-by-bunch feedback system is presented. The feedback system model represents the performance of a fast phase detector front end (including system noise and imperfections), a digital filter used to generate a correction voltage, and a power amplifier and beam kicker system. The combined ring-feedback system model is used to study the feedback system performance required to suppress instabilities and to quantify the dynamics of the system. Results are presented which show the time development of coupled bunch instabilities and the damping action of the feedback system. 3 refs., 5 figs., 2 tabs

  15. Novel Scanning Lens Instrument for Evaluating Fresnel Lens Performance: Equipment Development and Initial Results (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Herrero, R.; Miller, D. C.; Kurtz, S. R.; Anton, I.; Sala, G.

    2013-07-01

    A system dedicated to the optical transmittance characterization of Fresnel lenses has been developed at NREL, in collaboration with the UPM. The system quantifies the optical efficiency of the lens by generating a performance map. The shape of the focused spot may also be analyzed to understand change in the lens performance. The primary instrument components (lasers and CCD detector) have been characterized to confirm their capability for performing optical transmittance measurements. Measurements performed on SoG and PMMA lenses subject to a variety of indoor conditions (e.g., UV and damp heat) identified differences in the optical efficiency of the evaluated lenses, demonstrating the ability of the Scanning Lens Instrument (SLI) to distinguish between the aged lenses.

  16. Method for producing an isoplanatic aspheric monofocal intraocular lens, and resul ting lens

    OpenAIRE

    Barbero, Sergio; Marcos, Susana; Dorronsoro, Carlos; Montejo, Javier; Salazar Salegui, Pedro

    2010-01-01

    [EN] The invention can be used to obtain isoplanatic aspheric mono focal intraocular lenses in a viewing range of up to 25° (preferably up to 10°). The method comprises the following steps: l. mathematical defmition of an aphakic eye model; 2. mathematical definition of an intraocular lens model; 3. mathematical defmition of the implantation of the lens; 4. mathematical defmition of the merit function; 5. definition of the contour conditions; 6. defmition of a measurement for charact...

  17. Improvements in emittance wake field optimization for the SLAC Linear Collider

    CERN Document Server

    Decker, Franz Josef

    2003-01-01

    The transverse emittances in the SLAC Linear Collider can be severely diluted by collective wakefield effects and dispersion. For the 1997/98 SLC/SLD run important changes were implemented in the way the emittance is optimized. Early in the linac, where the energy spread is large due to BNS damping, the emittance growth is dominated by dispersion. In this regime emittance tuning bumps may introduce additional wakefield tails and their use is now avoided. At the end of the linac the energy spread is minimal and the emittance measurement is most sensitive to wakefield emittance dilution. In previous years, the emittances were tuned on wire scanners located near but not at the end of the linac (after about 90% of its length). Simulations show that emittance growth of up to 100% can occur in the remaining 10%. In this run wire scanners at the entrance of the Final Focus, the last place where the emittances can be measured, were used for the optimization. Screens at the end of the linac allow additional real time ...

  18. The Effect of the Feedback Controller on Superconducting Tokamak AC Losses + AC-CRPP user manual

    International Nuclear Information System (INIS)

    Schaerz, B.; Bruzzone, P.; Favez, J.Y.; Lister, J.B.; Zapretilina, E.

    2001-11-01

    Superconducting coils in a Tokamak are subject to AC losses when the field transverse to the coil current varies. A simple model to evaluate the AC losses has been derived and benchmarked against a complete model used in the ITER design procedure. The influence of the feedback control strategy on the AC losses is examined using this model. An improved controller is proposed, based on this study. (author)

  19. A Class I UV-Blocking (senofilcon A) Soft Contact Lens Prevents UVA-induced Yellow Fluorescence and NADH loss in the Rabbit Lens Nucleus in vivo

    Science.gov (United States)

    Giblin, Frank J.; Lin, Li-Ren; Simpanya, Mukoma F.; Leverenz, Victor R.; Fick, Catherine E.

    2012-01-01

    It is known that fluorescence, much of it caused by UVA light excitation, increases in the aging human lens, resulting in loss of sharp vision. This study used an in vivo animal model to investigate UVA-excited fluorescence in the rabbit lens, which contains a high level of the UVA chromophore NADH, existing both free and bound to λ-crystallin. Also, the ability of a Class I (senofilcon A) soft contact lens to protect against UVA-induced effects on the rabbit lens was tested. Rabbit eyes were irradiated with UVA light in vivo (100 mW/cm2 on the cornea) for 1 hour using monochromatic 365 nm light. Irradiation was conducted in the presence of either a senofilcon A contact lens, a minimally UV-absorbing lotrafilcon A contact lens, or no contact lens at all. Eyes irradiated without a contact lens showed blue 365 nm-excited fluorescence initially, but this changed to intense yellow fluorescence after 1 hour. Isolated, previously irradiated lenses exhibited yellow fluorescence originating from the lens nucleus when viewed under 365 nm light, but showed normal blue fluorescence arising from the cortex. Previously irradiated lenses also exhibited a faint yellow color when observed under visible light. The senofilcon A contact lens protected completely against the UVA-induced effects on fluorescence and lens yellowing, whereas the lotrafilcon A lens showed no protection. The UVA-exposure also produced a 53% loss of total NADH (free plus bound) in the lens nucleus, with only a 13% drop in the anterior cortex. NADH loss in the nucleus was completely prevented with use of a senofilcon A contact lens, but no significant protection was observed with a lotrafilcon A lens. Overall, the senofilcon A lens provided an average of 67% protection against UVA-induced loss of four pyridine nucleotides in four different regions of the lens. HPLC analysis with fluorescence detection indicated a nearly six-fold increase in 365 nm-excited yellow fluorescence arising from lens nuclear

  20. AcMNPV ac143 (odv-e18) is essential for mediating budded virus production and is the 30th baculovirus core gene

    International Nuclear Information System (INIS)

    McCarthy, Christina B.; Theilmann, David A.

    2008-01-01

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac143 (odv-e18) is a late gene that encodes for a predicted 9.6 kDa structural protein that locates to the occlusion derived viral envelope and viral induced intranuclear microvesicles [Braunagel, S.C., He, H., Ramamurthy, P., and Summers, M.D. (1996). Transcription, translation, and cellular localization of three Autographa californica nuclear polyhedrosis virus structural proteins: ODV-E18, ODV-E35, and ODV-EC27. Virology 222, 100-114.]. In this study we demonstrate that ac143 is actually a previously unrecognized core gene and that it is essential for mediating budded virus production. To examine the role of ac143 in the baculovirus life cycle, we used the AcMNPV bacmid system to generate an ac143 knockout (KO) virus (AcBAC ac142REP-ac143KO ). Fluorescence and light microscopy showed that infection by AcBAC ac142REP-ac143KO is limited to a single cell and titration assays confirmed that AcBAC ac142REP-ac143KO was unable to produce budded virus (BV). Progression to very late phases of the viral infection was evidenced by the development of occlusion bodies in the nuclei of transfected cells. This correlated with the fact that viral DNA replication was unaffected in AcBAC ac142REP-ac143KO transfected cells. The entire ac143 promoter, which includes three late promoter motifs, is contained within the ac142 open reading frame. Different deletion mutants of this region showed that the integrity of the ac142-ac143 core gene cluster was required for the bacmids to display wild-type patterns of viral replication, BV production and RNA transcription

  1. Multipoint photonic doppler velocimetry using optical lens elements

    Science.gov (United States)

    Frogget, Brent Copely; Romero, Vincent Todd

    2014-04-29

    A probe including a fisheye lens is disclosed to measure the velocity distribution of a moving surface along many lines of sight. Laser light, directed to the surface and then reflected back from the surface, is Doppler shifted by the moving surface, collected into fisheye lens, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to an index-matching lens and eventually to a fisheye lens. The fiber array flat polished and coupled to the index-matching lens using index-matching gel. Numerous fibers in a fiber array project numerous rays through the fisheye lens which in turn project many measurement points at numerous different locations to establish surface coverage over a hemispherical shape with very little crosstalk.

  2. Disassembly of the lens fiber cell nucleus to create a clear lens: the p27 descent

    Science.gov (United States)

    The eye lens is unique among tissues: it is transparent, does not form tumors, and the majority of its cells degrade their organelles, including their cell nuclei. A mystery for over a century, there has been considerable recent progress in elucidating mechanisms of lens fiber cell denucleation (LFC...

  3. Innovative application of AC-voltammetry in the characterization of oxides nanolayers formed on metals, under the effect of AC-perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, V.; Lazzari, L.; Ormellesse, M. [Politecnico di Milano, Milan (Italy). Dept. of Chemistry, Materials and Chemical Engineering; Spinelli, P. [Politecnico di Torino, Torino (Italy). Dept. of Materials Science and Chemical Engineering

    2008-07-01

    Stray AC-currents have been reported to cause many cases of unwanted corrosion on metallic structures. This study characterized the formation and stability of the surface oxide film formed on mild steel under the effect of AC voltage in a very basic environment. The response of the system to DC signals was examined, along with its reversibility to AC perturbations. SEM analysis was used to complement AC-Voltammetry. Reaction mechanisms responsible for the AC-corrosion were formulated. AC-Voltammetry involves the application of a controlled sinusoidal voltage onto a solid working electrode while it is being swept in a DC-voltage range, with the faradaic or capacitative components of the resulting AC-current being recorded. The innovative aspect is the application of AC-V to characterize its nano-surface while it is being affected by AC-signals. It was concluded that the AC-V can be useful for the study of redox processes occurring at the surface of a reactive electrode and for the application of a considerable AC perturbation to the electrode in a potentiostatically controlled way. According to the electrochemistry of the double layer, there are 3 main reactions in the NaOH 1M media that are not reversible to DC nor to AC perturbations in the range of cathodic protection of mild steel. When designing metallic systems susceptible to stray currents, the AC-V could quantify the final faradaic, resistive and capacitative responses. 6 refs., 1 fig.

  4. Automated Fresnel lens tester system

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, G.S.

    1981-07-01

    An automated data collection system controlled by a desktop computer has been developed for testing Fresnel concentrators (lenses) intended for solar energy applications. The system maps the two-dimensional irradiance pattern (image) formed in a plane parallel to the lens, whereas the lens and detector assembly track the sun. A point detector silicon diode (0.5-mm-dia active area) measures the irradiance at each point of an operator-defined rectilinear grid of data positions. Comparison with a second detector measuring solar insolation levels results in solar concentration ratios over the image plane. Summation of image plane energies allows calculation of lens efficiencies for various solar cell sizes. Various graphical plots of concentration ratio data help to visualize energy distribution patterns.

  5. Perubahan Sosial Berbasis Tasawuf: Studi Kasus Fethullah Gülen Dan Gülen Movement

    Directory of Open Access Journals (Sweden)

    Sulaiman Sulaiman

    2016-06-01

    Full Text Available Abstract: This article aims at analyzing Fethullah Gülen and the Gülen Movement which have succeeded in performing social change based on the teaching of Sufism. He did Sufism creativity in order that Sufism teaching was able to respond the changes that occur in the modernlife. He believed that, only by reinterpretation and contextualization of Sufism, the spiritual dimension of Islam would be able to perform the transformation or social change among the Muslims. Therefore, by using Max Weber’s theory of social action, this paper will analyze three key teachings of Sufism of Gülen: ascetic (zuhd, inbisat (expansion, and hizmet. Based on the Weber's theory, Gülen occupied a very central and authoritative position: agent/actor, action and meaning. As a source of meaning and interpreter of meaning, the key concepts of Sufism were transformed by Gülen to the internal and external communities so that they had made a move to do social movements and humanity. For the followers of Gülen, the movement was called the Gülen Movement or the Hizmet Movement which was engaged in the fields of education, health care, humanitarian assistance, and the mass media. All forms of movement were entirely based on the spiritual values of Islam that had been formulated by Gülen. الملخص: يهدف هذا البحث إلى تحليل شخصية فتح الله غولن وحركته الذي تمكن من القيام بالتغيير الاجتماعي على أساس التعاليم الصوفية. إن فتح الله غولن قام بإحياء التصوف في صورته الجدّية والحيوية في حياة الإنسان المعاصر. ويعتقد أن إعادة التفسير لتعاليم التصوف مع مراعاة الواقع قادرة على التغيير الاجتماعي بين المسلمين. من أجل ذلك، أن استخدام نظرية ويبر، يمكن تحليل تعاليم التصوف الثلاثة

  6. Preliminary Conceptual Design Report for the FACET-II Project at SLAC National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, Mark [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-04-22

    Plasma wakefield acceleration has the potential to dramatically shrink the size and cost of particle accelerators. Research at the SLAC National Accelerator Laboratory has demonstrated that plasmas can provide 1,000 times the acceleration in a given distance compared with current technologies. Developing revolutionary and more efficient acceleration techniques that allow for an affordable high-energy collider is the focus of FACET, a National User Facility at SLAC. The existing FACET National User Facility uses part of SLAC’s two-mile-long linear accelerator to generate high-density beams of electrons and positrons. FACET-II is a new test facility to develop advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. It is the only facility in the world with high energy positron beams. FACET-II provides a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique. It will synergistically pursue accelerator science that is vital to the future of both advanced acceleration techniques for High Energy Physics, ultra-high brightness beams for Basic Energy Science, and novel radiation sources for a wide variety of applications. The design parameters for FACET-II are set by the requirements of the plasma wakefield experimental program. To drive the plasma wakefield requires a high peak current, in excess of 10kA. To reach this peak current, the electron and positron design bunch size is 10μ by 10μ transversely with a bunch length of 10μ. This is more than 200 times better than what has been achieved at the existing FACET. The beam energy is 10 GeV, set by the Linac length available and the repetition rate is up to 30 Hz. The FACET-II project is scheduled to be constructed in three major stages. Components of the project discussed in detail include the following: electron injector, bunch compressors and linac, the positron system, the Sector 20 sailboat and W chicanes

  7. Characteristics of soft X-ray lens

    International Nuclear Information System (INIS)

    Qin Yi

    2007-12-01

    A soft X-lens was devised with waveguide X-ray optics of total external reflection (TER). The lens consists of a stack of 1 387 TER waveguides with inner diameter of 0.45 mm and outer diameter of 0.60 mm. With the help of plasma sources of soft X-ray radiation, high density of pure soft X-ray radiation (without plasma expansion fragments) with broad-band spectral range can be obtained at the focus of the lens. As laser-plasma is considered, the radiation density of 1.3 x 10 5 W/cm 2 is obtained, the transmission coefficient is 18.6%, the ratio of the density at the focus with and without the lens is 1000 and the radiation capture is 28.9 degree. The density of 0.5 TW/cm 2 can be obtained as far as Qiang-Guang I facility is considered. (authors)

  8. High voltage AC/AC electrochemical capacitor operating at low temperature in salt aqueous electrolyte

    Science.gov (United States)

    Abbas, Qamar; Béguin, François

    2016-06-01

    We demonstrate that an activated carbon (AC)-based electrochemical capacitor implementing aqueous lithium sulfate electrolyte in 7:3 vol:vol water/methanol mixture can operate down to -40 °C with good electrochemical performance. Three-electrode cell investigations show that the faradaic contributions related with hydrogen chemisorption in the negative AC electrode are thermodynamically unfavored at -40 °C, enabling the system to work as a typical electrical double-layer (EDL) capacitor. After prolonged floating of the AC/AC capacitor at 1.6 V and -40°C, the capacitance, equivalent series resistance and efficiency remain constant, demonstrating the absence of ageing related with side redox reactions at this temperature. Interestingly, when temperature is increased back to 24 °C, the redox behavior due to hydrogen storage reappears and the system behaves as a freshly prepared one.

  9. Development of an accommodating intra-ocular lens - In vitro prevention of re-growth of pig and rabbit lens capsule epithelial cells

    NARCIS (Netherlands)

    van Kooten, Theo G.; Koopmans, Steven; Terwee, Thom; Norrby, Sverker; Hooymans, J. M. M.; Busscher, Henk J.

    2006-01-01

    Cataract surgery is routinely performed to replace the clouded lens by a rigid polymeric intra-ocular lens unable to accommodate. By implanting a silicone gel into an intact capsular bag the accommodating properties of the natural lens can be maintained or enhanced. The implantation success of

  10. Effects of x-irradiation on lens reducing systems

    International Nuclear Information System (INIS)

    Giblin, F.J.; Chakrapani, B.; Reddy, V.N.

    1978-01-01

    Studies have been made of the effects of x ray on various lens reducing systems including the levels of NADPH and glutathione (GSH), the activity of the hexose monophosphate shunt (HMS), and the activities of certain enzymes including glutathion reductase, glutathione peroxidase, and glucose-6-phosphate dehydrogenase (G-6-PD). It was found that during several weeks following x irradiation but prior to cataract formation there was very little change in the number of reduced -SH groups per unit weight of lens protein but that, with the appearance of cataract, there was a sudden loss of protein -SH groups. In contrast, the concentration of GSH in the x-rayed lens decreased throughout the experimental period. Similarly, the concentration of NADPH in the x-rayed lens was found to decrease significantly relative to controls one week prior to cataract formation and the ratio of NADPH to NADP + in the lens shifted at this time period from a value greater than 1.0 in the control lens to less than 1.0 in the x-rayed lens. A corresponding decrease occurred in the activity of the HMS in x-rayed lenses as measured by culture in the presence of 1- 14 C-labelled glucose. G-6-PD was partially inactivated in the x-rayed lens. Of the eight enzymes studied, G-6-PD appeared to be the most sensitive to x-irradiation. The data indicate that x-irradiation results in a steady decrease in the effectiveness of lens reducing systems and that, when these systems reach a critically low point, sudden oxidation of protein -SH groups and formation of high molecular weight protein aggregates may be initiated

  11. AcEST: DK954361 [AcEST

    Lifescience Database Archive (English)

    Full Text Available in 5-4 OS=Homo sap... 33 1.1 sp|Q9DBY1|SYVN1_MOUSE E3 ubiquitin-protein ligase synoviolin OS=... 33 1.4 sp|Q...86TM6|SYVN1_HUMAN E3 ubiquitin-protein ligase synoviolin OS=... 33 1.4 sp|O55188|DMP1_MOUSE Dentin matrix ac

  12. Photon nanojet lens: design, fabrication and characterization

    International Nuclear Information System (INIS)

    Xu, Chen; Zhang, Sichao; Shao, Jinhai; Lu, Bing-Rui; Chen, Yifang; Mehfuz, Reyad; Drakeley, Stacey; Huang, Fumin

    2016-01-01

    In this paper, a novel nanolens with super resolution, based on the photon nanojet effect through dielectric nanostructures in visible wavelengths, is proposed. The nanolens is made from plastic SU-8, consisting of parallel semi-cylinders in an array. This paper focuses on the lens designed by numerical simulation with the finite-difference time domain method and nanofabrication of the lens by grayscale electron beam lithography combined with a casting/bonding/lift-off transfer process. Monte Carlo simulation for injected charge distribution and development modeling was applied to define the resultant 3D profile in PMMA as the template for the lens shape. After the casting/bonding/lift-off process, the fabricated nanolens in SU-8 has the desired lens shape, very close to that of PMMA, indicating that the pattern transfer process developed in this work can be reliably applied not only for the fabrication of the lens but also for other 3D nanopatterns in general. The light distribution through the lens near its surface was initially characterized by a scanning near-field optical microscope, showing a well defined focusing image of designed grating lines. Such focusing function supports the great prospects of developing a novel nanolithography based on the photon nanojet effect. (paper)

  13. Protein synthesis in x-irradiated rabbit lens

    International Nuclear Information System (INIS)

    Garadi, R.; Foltyn, A.R.; Giblin, F.J.; Reddy, V.N.

    1984-01-01

    The present study deals with the incorporation of 35 S methionine into lens crystallins as a function of time after x-irradiation. Crystallin synthesis is first affected approximately 4 weeks following x-irradiation. This coincides with the time period at which the ratio of the two cations in the lens is affected, as shown in earlier studies. A greater decrease in 35 S-methionine incorporation into crystallins is observed between 5-7 weeks following x-irradiation in good agreement with a cation imbalance at these time intervals. These studies also revealed for the first time that the change in cation distribution can affect not only crystallin synthesis, but also the synthesis of certain polypeptides of lens membranes. No alteration in protein synthesis could be detected in lens epithelium even after 7 weeks following irradiation. In addition to the effect of Na+ and K+ levels on protein synthesis, an impaired transport of amino acids into the x-rayed lens was also found to be a factor in the observed reduction in synthesis of the crystallin, cytoskeletal and membrane proteins of the fiber cells. It is concluded that Na+/K+ ratio as well as the availability of amino acids in the lens are important factors in protein synthesis of x-ray cataracts

  14. 21 CFR 886.4440 - AC-powered magnet.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and remove...

  15. 21 CFR 886.1410 - Ophthalmic trial lens clip.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens clip. 886.1410 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1410 Ophthalmic trial lens clip. (a) Identification. An ophthalmic trial lens clip is a device intended to hold prisms, spheres, cylinders, or...

  16. 21 CFR 886.1415 - Ophthalmic trial lens frame.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens frame. 886.1415 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1415 Ophthalmic trial lens frame. (a) Identification. An opthalmic trial lens frame is a mechanical device intended to hold trial lenses for vision...

  17. An adjustable electron achromat for cathode lens microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tromp, R.M., E-mail: rtromp@us.ibm.com [IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States); Leiden Institute of Physics, Kamerlingh Onnes Laboratory, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

    2015-12-15

    Chromatic aberration correction in light optics began with the invention of a two-color-corrected achromatic crown/flint lens doublet by Chester Moore Hall in 1730. Such color correction is necessary because any single glass shows dispersion (i.e. its index of refraction changes with wavelength), which can be counteracted by combining different glasses with different dispersions. In cathode lens microscopes (such as Photo Electron Emission Microscopy – PEEM) we encounter a similar situation, where the chromatic aberration coefficient of the cathode lens shows strong dispersion, i.e. depends (non-linearly) on the energy with which the electrons leave the sample. Here I show how a cathode lens in combination with an electron mirror can be configured as an adjustable electron achromat. The lens/mirror combination can be corrected at two electron energies by balancing the settings of the electron mirror against the settings of the cathode lens. The achromat can be adjusted to deliver optimum performance, depending on the requirements of a specific experiment. Going beyond the achromat, an apochromat would improve resolution and transmission by a very significant margin. I discuss the requirements and outlook for such a system, which for now remains a wish waiting for fulfilment. - Highlights: • The properties of cathode objective lens plus electron mirror are discussed. • In analogy with light-optical achromats, cathode lens plus mirror can be configured as an electron achromat. • Unlike light optics, the electron achromat can be adjusted to best fulfill experimental requirements.

  18. Fermat's least-time principle and the embedded transparent lens

    Science.gov (United States)

    Kantowski, R.; Chen, B.; Dai, X.

    2013-10-01

    We present a simplified version of the lowest-order embedded point mass gravitational lens theory and then make the extension of this theory to any embedded transparent lens. Embedding a lens effectively reduces the gravitational potential’s range, i.e., partially shields the lensing potential because the lens mass is made a contributor to the mean mass density of the Universe and not simply superimposed upon it. We give the time-delay function for the embedded point mass lens from which we can derive the simplified lens equation by applying Fermat’s least-time principle. Even though rigorous derivations are only made for the point mass in a flat background, the generalization of the lens equation to lowest order for any distributed lens in any homogeneous background is obvious. We find from this simplified theory that embedding can introduce corrections above the few percent level in weak lensing shears caused by large clusters but only at large impacts. The potential part of the time delay is also affected in strong lensing at the few percent level. Additionally we again confirm that the presence of a cosmological constant alters the gravitational deflection of passing photons.

  19. Lens regeneration in axolotl: new evidence of developmental plasticity

    Directory of Open Access Journals (Sweden)

    Suetsugu-Maki Rinako

    2012-12-01

    Full Text Available Abstract Background Among vertebrates lens regeneration is most pronounced in newts, which have the ability to regenerate the entire lens throughout their lives. Regeneration occurs from the dorsal iris by transdifferentiation of the pigment epithelial cells. Interestingly, the ventral iris never contributes to regeneration. Frogs have limited lens regeneration capacity elicited from the cornea during pre-metamorphic stages. The axolotl is another salamander which, like the newt, regenerates its limbs or its tail with the spinal cord, but up until now all reports have shown that it does not regenerate the lens. Results Here we present a detailed analysis during different stages of axolotl development, and we show that despite previous beliefs the axolotl does regenerate the lens, however, only during a limited time after hatching. We have found that starting at stage 44 (forelimb bud stage lens regeneration is possible for nearly two weeks. Regeneration occurs from the iris but, in contrast to the newt, regeneration can be elicited from either the dorsal or the ventral iris and, occasionally, even from both in the same eye. Similar studies in the zebra fish concluded that lens regeneration is not possible. Conclusions Regeneration of the lens is possible in the axolotl, but differs from both frogs and newts. Thus the axolotl iris provides a novel and more plastic strategy for lens regeneration.

  20. 21 CFR 886.1405 - Ophthalmic trial lens set.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens set. 886.1405 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1405 Ophthalmic trial lens set. (a) Identification. An ophthalmic trial lens set is a device that is a set of lenses of various dioptric powers...

  1. Computer optimization of retarding lens systems for ESCA spectrometers

    International Nuclear Information System (INIS)

    Wannberg, B.; Skoellermo, A.

    1977-01-01

    The performance of four-element electrostatic lenses as retarding systems between source and analyzer in ESCA spectrometers is calculated. The potential distribution in the lens is defined by an axial potential of the type phi(z)=V 0 +Σ(Vsub(i)-Vsub(i-1))/2 - tanh (ω/asub(i)(z-zsub(i))). For a given general shape of the lens and a given retardation ratio, the potentials of the two middle electrodes are fitted to give a paraxial image with a prescribed magnification at the exit slit of the lens system. The equipotential surfaces forming the electrodes are found by calculating the potential in an off-axis point, using the series expansion. All third-order geometrical and first-order chromatic aberrations of the lenses are calculated and used together with the second-order aberrations of the analyzer to calculate optimum dimensions of the lens elements and of the emittance-defining slits. A computer program, of which one part calculates the lens properties and one the properties of the entire system lens-analyzer, is described. Two lens systems are presented in some detail. The first one is intended for use with a hemispherical electrostatic analyzer. The angular acceptance is here defined by an aperture stop inside the lens. In this system, the image position and magnification can be kept constant for retardation ratios at least between 1:2 and 60:1, with moderate potentials on the middle electrodes. The second lens system is designed for a magnetic spectrometer of the π√2-type. Here, the central trajectory in the lens is slightly curved by the magnetic field, and the angular acceptance is defined by a baffle after the lens. This system is optimized for a constant retardation ratio of 5:1. (Auth.)

  2. Candidate gravitational microlensing events for future direct lens imaging

    International Nuclear Information System (INIS)

    Henderson, C. B.; Gould, A.; Gaudi, B. S.; Park, H.; Han, C.; Sumi, T.; Koshimoto, N.; Udalski, A.; Tsapras, Y.; Bozza, V.; Abe, F.; Fukunaga, D.; Itow, Y.; Masuda, K.; Bennett, D. P.; Bond, I. A.; Ling, C. H.; Botzler, C. S.; Freeman, M.; Fukui, A.

    2014-01-01

    The mass of the lenses giving rise to Galactic microlensing events can be constrained by measuring the relative lens-source proper motion and lens flux. The flux of the lens can be separated from that of the source, companions to the source, and unrelated nearby stars with high-resolution images taken when the lens and source are spatially resolved. For typical ground-based adaptive optics (AO) or space-based observations, this requires either inordinately long time baselines or high relative proper motions. We provide a list of microlensing events toward the Galactic bulge with high relative lens-source proper motion that are therefore good candidates for constraining the lens mass with future high-resolution imaging. We investigate all events from 2004 to 2013 that display detectable finite-source effects, a feature that allows us to measure the proper motion. In total, we present 20 events with μ ≳ 8 mas yr –1 . Of these, 14 were culled from previous analyses while 6 are new, including OGLE-2004-BLG-368, MOA-2005-BLG-36, OGLE-2012-BLG-0211, OGLE-2012-BLG-0456, MOA-2012-BLG-532, and MOA-2013-BLG-029. In ≲12 yr from the time of each event the lens and source of each event will be sufficiently separated for ground-based telescopes with AO systems or space telescopes to resolve each component and further characterize the lens system. Furthermore, for the most recent events, comparison of the lens flux estimates from images taken immediately to those estimated from images taken when the lens and source are resolved can be used to empirically check the robustness of the single-epoch method currently being used to estimate lens masses for many events.

  3. Candidate gravitational microlensing events for future direct lens imaging

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, C. B.; Gould, A.; Gaudi, B. S. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Park, H.; Han, C. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Sumi, T.; Koshimoto, N. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Bozza, V. [Department of Physics, University of Salerno, I-84084 Fisciano (Italy); Abe, F.; Fukunaga, D.; Itow, Y.; Masuda, K. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Bond, I. A.; Ling, C. H. [Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland 0745 (New Zealand); Botzler, C. S.; Freeman, M. [Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001 (New Zealand); Fukui, A. [School of Chemical and Physical Sciences, Victoria University, Wellington 6140 (New Zealand); Collaboration: MOA Collaboration; OGLE Collaboration; μFUN Collaboration; RoboNet Collaboration; and others

    2014-10-10

    The mass of the lenses giving rise to Galactic microlensing events can be constrained by measuring the relative lens-source proper motion and lens flux. The flux of the lens can be separated from that of the source, companions to the source, and unrelated nearby stars with high-resolution images taken when the lens and source are spatially resolved. For typical ground-based adaptive optics (AO) or space-based observations, this requires either inordinately long time baselines or high relative proper motions. We provide a list of microlensing events toward the Galactic bulge with high relative lens-source proper motion that are therefore good candidates for constraining the lens mass with future high-resolution imaging. We investigate all events from 2004 to 2013 that display detectable finite-source effects, a feature that allows us to measure the proper motion. In total, we present 20 events with μ ≳ 8 mas yr{sup –1}. Of these, 14 were culled from previous analyses while 6 are new, including OGLE-2004-BLG-368, MOA-2005-BLG-36, OGLE-2012-BLG-0211, OGLE-2012-BLG-0456, MOA-2012-BLG-532, and MOA-2013-BLG-029. In ≲12 yr from the time of each event the lens and source of each event will be sufficiently separated for ground-based telescopes with AO systems or space telescopes to resolve each component and further characterize the lens system. Furthermore, for the most recent events, comparison of the lens flux estimates from images taken immediately to those estimated from images taken when the lens and source are resolved can be used to empirically check the robustness of the single-epoch method currently being used to estimate lens masses for many events.

  4. Optofluidic lens actuated by laser-induced solutocapillary forces

    Science.gov (United States)

    Malyuk, A. Yu.; Ivanova, N. A.

    2017-06-01

    We demonstrate an adaptive liquid lens controlled by laser-induced solutocapillary forces. The liquid droplet serving as a lens is formed in a thin layer of binary liquid mixture by surface tension driven flows caused by the thermal action of laser irradiation. The shape of droplet, its aperture and the focal length are reversibly changed without hysteresis by varying the intensity of the laser beam. The focal length variation range of the droplet-lens lies in between infinity (a flat layer) to 15 mm (a curved interface). The droplet-lens is capable to adjust the in-plane lateral position in response to a displacement of the laser beam. The proposed laser controlled droplet-lens will enable to develop smart liquid optical devices, which can imitate the accommodation reflex and pupillary light reflex of the eye.

  5. EDEL: ENEA dosemeter for eye lens

    International Nuclear Information System (INIS)

    Ferrari, Paolo; Mariotti, Francesca; Campani, Lorenzo

    2016-01-01

    Since the publication of International Commission on Radiological Protection statement in 2011 on tissue reaction, eye lens radiation protection played an important role in exposed personnel dosimetry. For this reason, the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) Individual Monitoring Service decided to study a prototype to fulfil specific requests (e.g. for survey in interventional department and intercomparisons). On the basis of such preliminary investigation, a new eye lens dosemeter was developed. The new dosemeter, named EDEL (ENEA Dosemeter for Eye Lens), was characterised in terms of H p (3), the operational quantity related to eye lens monitoring. The investigation was performed experimentally and optimised using the Monte Carlo MCNP6 code. The new prototype was thought to fulfil two main requests: the reliability of the dosimetric data and the portability of the dosemeter itself. The new dosemeter will soon be supplied to the collaborating hospitals for workplace test measurements. (authors)

  6. Gravitational lens effect and pregalactic halo objects

    International Nuclear Information System (INIS)

    Bontz, R.J.

    1979-01-01

    The changes in flux, position, and size of a distant extended (galaxy, etc.) source that result from the gravitational lens action of a massive opaque object are discussed. The flux increase is described by a single function of two parameters. One of these parameters characterizes the strength of the gravitational lens, the other describes the alignment of source and lens object. This function also describes the relative intensity of the images formed by lens. ( A similar formalism is discussed by Bourassa et al. for a point source). The formalism is applied to the problem of the galactic halo. It appears that a massive (10 1 2 M/sub sun/) spherical halo surrounding the visible part of the galaxy is consistent with the observable properties of extragalactic sources

  7. Tinting of intraocular lens implants

    International Nuclear Information System (INIS)

    Zigman, S.

    1982-01-01

    Intraocular lens (IOL) implants of polymethyl methacrylate (PMMA) lack an important yellow pigment useful as a filter in the visual process and in the protection of the retina from short-wavelength radiant energy. The ability to produce a yellow pigment in the PMMA used in IOL implants by exposure to near-ultraviolet (UV) light was tested. It was found that the highly cross-linked material in Copeland lens blanks was tinted slightly because of this exposure. The absorptive properties of lens blanks treated with near-UV light in this way approached that of the absorptive properties of human lenses. This finding shows that it is possible to alter IOL implants simply so as to induce a pale-yellow pigment in them to improve the visual process and to protect the retinas of IOL users

  8. Tinting of intraocular lens implants

    Energy Technology Data Exchange (ETDEWEB)

    Zigman, S.

    1982-06-01

    Intraocular lens (IOL) implants of polymethyl methacrylate (PMMA) lack an important yellow pigment useful as a filter in the visual process and in the protection of the retina from short-wavelength radiant energy. The ability to produce a yellow pigment in the PMMA used in IOL implants by exposure to near-ultraviolet (UV) light was tested. It was found that the highly cross-linked material in Copeland lens blanks was tinted slightly because of this exposure. The absorptive properties of lens blanks treated with near-UV light in this way approached that of the absorptive properties of human lenses. This finding shows that it is possible to alter IOL implants simply so as to induce a pale-yellow pigment in them to improve the visual process and to protect the retinas of IOL users.

  9. Emittance studies of the BNL/SLAC/UCLA 1.6 cell photocathode rf gun

    International Nuclear Information System (INIS)

    Palmer, D.T.; Miller, R.H.; Wang, X.J.

    1997-01-01

    The symmetrized 1.6 cell S-band photocathode gun developed by the BNL/SLAC/UCLA collaboration is in operation at the Brookhaven Accelerator Test Facility (ATF). A novel emittance compensation solenoid magnet has also been designed, built and is in operation at the ATF. These two subsystems form an emittance compensated photoinjector used for beam dynamics, advanced acceleration and free electron laser experiments at the ATF. The highest acceleration field achieved on the copper cathode is 150 MV/m, and the guns normal operating field is 130 MV/m. The maximum rf pulse length is 3 micros. The transverse emittance of the photoelectron beam were measured for various injection parameters. The 1 nC emittance results are presented along with electron bunch length measurements that indicated that at above the 400 pC, space charge bunch lengthening is occurring. The thermal emittance, ε o , of the copper cathode has been measured

  10. 600 kV modulator design for the SLAC Next Linear Collider Test Accelerator

    International Nuclear Information System (INIS)

    Harris, K.; de Lamare, J.; Nesterov, V.; Cassel, R.

    1992-07-01

    Preliminary design for the SLAC Next Linear Collider Test Accelerator (NLCTA) requires a pulse power source to produce a 600 kV, 600 A, 1.4 μs, 0.1% flat top pulse with rise and fall times of approximately 100 ns to power an X-Band klystron with a microperveance of 1.25 at ∼ 100 MW peak RF power. The design goals for the modulator, including those previously listed, are peak modulator pulse power of 340 MW operating at 120 Hz. A three-stage darlington pulse-forming network, which produces a >100 kV, 1.4 μs pulse, is coupled to the klystron load through a 6:1 pulse transformer. Careful consideration of the transformer leakage inductance, klystron capacitance, system layout, and component choice is necessary to produce the very fast rise and fall times at 600 kV operating continuously at 120 Hz

  11. Acid phosphatase and lipid peroxidation in human cataractous lens epithelium

    Directory of Open Access Journals (Sweden)

    Vasavada Abhay

    1993-01-01

    Full Text Available The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium. In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium. From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.

  12. The partial coherence modulation transfer function in testing lithography lens

    Science.gov (United States)

    Huang, Jiun-Woei

    2018-03-01

    Due to the lithography demanding high performance in projection of semiconductor mask to wafer, the lens has to be almost free in spherical and coma aberration, thus, in situ optical testing for diagnosis of lens performance has to be established to verify the performance and to provide the suggesting for further improvement of the lens, before the lens has been build and integrated with light source. The measurement of modulation transfer function of critical dimension (CD) is main performance parameter to evaluate the line width of semiconductor platform fabricating ability for the smallest line width of producing tiny integrated circuits. Although the modulation transfer function (MTF) has been popularly used to evaluation the optical system, but in lithography, the contrast of each line-pair is in one dimension or two dimensions, analytically, while the lens stand along in the test bench integrated with the light source coherent or near coherent for the small dimension near the optical diffraction limit, the MTF is not only contributed by the lens, also by illumination of platform. In the study, the partial coherence modulation transfer function (PCMTF) for testing a lithography lens is suggested by measuring MTF in the high spatial frequency of in situ lithography lens, blended with the illumination of partial and in coherent light source. PCMTF can be one of measurement to evaluate the imperfect lens of lithography lens for further improvement in lens performance.

  13. Intraocular Lens Calcification; a Clinicopathologic Report

    Directory of Open Access Journals (Sweden)

    Mozhgan Rezaei-Kanavi

    2009-04-01

    Full Text Available

    PURPOSE: To describe the clinical and pathological features of a case of hydrogel intraocular lens (IOL calcification. CASE REPORT: A 48-year-old man underwent explantation of a single-piece hydrophilic acrylic intraocular lens in his left eye because of decreased visual acuity and milky white opalescence of the IOL. The opacified lens was exchanged uneventfully with a hydrophobic acrylic IOL. Gross examination of the explanted IOL disclosed opacification of the optic and haptics. Full-thickness sections of the lens optic were stained with hematoxylin and eosin (H&E, von Kossa and Gram Tworts'. Microscopic examination of the sections revealed fine and diffuse basophilic granular deposits of variable size within the lens optic parallel to the lens curvature but separated from the surface by a moderately clear zone. The deposits were of high calcium content as evident by dark brown staining with von Kossa. Gram Tworts' staining disclosed no microorganisms. CONCLUSION: This report further contributes to the existing literature on hydrogel IOL calcification.

  14. Contact lens rehabilitation following repaired corneal perforations

    Science.gov (United States)

    Titiyal, Jeewan S; Sinha, Rajesh; Sharma, Namrata; Sreenivas, V; Vajpayee, Rasik B

    2006-01-01

    Background Visual outcome following repair of post-traumatic corneal perforation may not be optimal due to presence of irregular keratometric astigmatism. We performed a study to evaluate and compare rigid gas permeable contact lens and spectacles in visual rehabilitation following perforating corneal injuries. Method Eyes that had undergone repair for corneal perforating injuries with or without lens aspiration were fitted rigid gas permeable contact lenses. The fitting pattern and the improvement in visual acuity by contact lens over spectacle correction were noted. Results Forty eyes of 40 patients that had undergone surgical repair of posttraumatic corneal perforations were fitted rigid gas permeable contact lenses for visual rehabilitation. Twenty-four eyes (60%) required aphakic contact lenses. The best corrected visual acuity (BCVA) of ≥ 6/18 in the snellen's acuity chart was seen in 10 (25%) eyes with spectacle correction and 37 (92.5%) eyes with the use of contact lens (p < 0.001). The best-corrected visual acuity with spectacles was 0.20 ± 0.13 while the same with contact lens was 0.58 ± 0.26. All the patients showed an improvement of ≥ 2 lines over spectacles in the snellen's acuity chart with contact lens. Conclusion Rigid gas permeable contact lenses are better means of rehabilitation in eyes that have an irregular cornea due to scars caused by perforating corneal injuries. PMID:16536877

  15. Effect of contact lens use on Computer Vision Syndrome.

    Science.gov (United States)

    Tauste, Ana; Ronda, Elena; Molina, María-José; Seguí, Mar

    2016-03-01

    To analyse the relationship between Computer Vision Syndrome (CVS) in computer workers and contact lens use, according to lens materials. Cross-sectional study. The study included 426 civil-service office workers, of whom 22% were contact lens wearers. Workers completed the Computer Vision Syndrome Questionnaire (CVS-Q) and provided information on their contact lenses and exposure to video display terminals (VDT) at work. CVS was defined as a CVS-Q score of 6 or more. The covariates were age and sex. Logistic regression was used to calculate the association (crude and adjusted for age and sex) between CVS and individual and work-related factors, and between CVS and contact lens type. Contact lens wearers are more likely to suffer CVS than non-lens wearers, with a prevalence of 65% vs 50%. Workers who wear contact lenses and are exposed to the computer for more than 6 h day(-1) are more likely to suffer CVS than non-lens wearers working at the computer for the same amount of time (aOR = 4.85; 95% CI, 1.25-18.80; p = 0.02). Regular contact lens use increases CVS after 6 h of computer work. © 2016 The Authors Ophthalmic & Physiological Optics © 2016 The College of Optometrists.

  16. The effect of compliance on contact lens case contamination.

    Science.gov (United States)

    Tilia, Daniel; Lazon de la Jara, Percy; Zhu, Hua; Naduvilath, Thomas J; Holden, Brien A

    2014-03-01

    To determine the efficacy of written instructions on contact lens case hygiene and to quantify the effect of noncompliance on contact lens case contamination. Data were retrospectively analyzed from 16 prospective, 3-month daily-wear studies during which six commercially available silicone hydrogel contact lenses and seven lens care solutions (LCS) were tested following a similar protocol. Verbal instructions regarding case hygiene (rinse case with LCS, not tap water) were given in nine studies, while the same instructions were given verbally and in written format in seven studies. A survey on contact lens, LCS, and lens case hygiene was completed at 1- and 3-month visits and compliance with case hygiene instructions was determined. Regular contact lens cases were used for 1 month and collected for microbial analysis at the 1- and 3-month visits. The rate of case contamination and the types of microbes contaminating cases were evaluated. Participants given verbal and written instructions were more likely to be compliant with case hygiene instructions than those just given verbal instructions (odds ratio [OR]: 2.19, p hygiene can be improved by effective communication of instructions. Contact lens wearers should be actively discouraged from rinsing contact lens cases with tap water because of the increased risk of GNB contamination.

  17. Lens dislocation has a possible relationship with laser iridotomy

    Directory of Open Access Journals (Sweden)

    Mutoh T

    2012-12-01

    Full Text Available Tetsuya Mutoh,1,2 Kevin F Barrette,2 Yukihiro Matsumoto,1 Makoto Chikuda11Department of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya City, Saitama, Japan; 2Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USAAbstract: We report our recent experience of four eyes with spontaneous lens dislocation in four patients with no history of trauma or any systemic disease associated with zonular dialysis. Lens dislocation developed with 0.5 to 6 months following laser iridotomy. All patients were male and two eyes were complicated with acute primary angle closure glaucoma preoperatively. Case 1 showed bilateral lens dislocation, while cases 2 and 3 involved unilateral lens dislocation. Cases 2 and 3 showed lenses completely dislocated into the vitreous cavity. All cases needed lens removal and scleral fixation of intraocular lenses. Final visual acuity was 1.2 in all cases. We suspect that laser iridotomy may induce localized zonular dialysis that results in progressive zonular weakness, leading to lens dislocation.Keywords: lens dislocation, laser iridotomy, primary angle closure glaucoma

  18. Surgical effect of traumatic lens dislocation with secondary glaucoma

    Directory of Open Access Journals (Sweden)

    Xiao-Dan Zhang

    2014-10-01

    Full Text Available AIM: To retrospectively evaluate the effect of lens extraction combined with vitrectomy to treat traumatic lens dislocation with secondary glaucoma.METHODS:Thirty-one eyes(31 casesof lens dislocation caused by blunt trauma with secondary glaucoma were treated respectively with cataract extraction combined with anterior vitrectomy, trabeculectomy and intraocular lens implantation. The visual acuity and pressure were observed 1wk, 1 and 3mo after operative. RESULTS:Thirty-one eyes were all complete the operation successfully, and 6 eyes were given combined trabeculectomy, 9 eyes were implanted anterior chamber intraocular lens implantation(IOLand 15 eyes were given posterior chamber suture fixation. Sixteen eyes were implanted in one-stage operation, while 8 eyes were implanted in two-stage operation. All intraocular pressure(IOPwere controlled to the normal level after operation and 23 eyes had visual acuity of more than 0.3.CONCLUSION:Lens extraction combined with vitrectomy is an effective method for treatment of lens dislocation with secondary glaucoma. In order to control the IOP and get well visual function, we should choose IOL implantation or trabeculectomy according to the patient's condition.

  19. Lens transmission measurement for an absolute radiation thermometer

    International Nuclear Information System (INIS)

    Hao, X.; Yuan, Z.; Lu, X.

    2013-01-01

    The lens transmission for the National Institute of Metrology of China absolute radiation thermometer is measured by a hybrid method. The results of the lens transmission measurements are 99.002% and 86.792% for filter radiometers with center wavelengths 633 nm and 900 nm, respectively. These results, after correcting for diffraction factors and the size-of-source effect when the lens is incorporated within the radiometer, can be used for measurement of thermodynamic temperature. The expanded uncertainty of the lens transmission measurement system has been evaluated. It is 1.3×10 −3 at 633 nm and 900 nm, respectively

  20. Chemical performance of multi-environment trials in lens (Lens culinaris M.).

    Science.gov (United States)

    Karadavut, Ufuk; Palta, Cetin

    2010-01-15

    Genotype-environment (GE) interaction has been a major effect to determine stable lens (Lens culinaris (Medik.) Merr.) cultivars for chemical composition in Turkey. Utilization of the lines depends on their agronomic traits and stability of the chemical composition in diverse environments. The objectives of this study were: (i) to evaluate the influence of year and location on the chemical composition of lens genotypes; and (ii) to determine which cultivar is the most stable. Genotypes were evaluated over 3 years (2005, 2006 and 2007) at four locations in Turkey. Effects of year had the largest impact on all protein contents. GE interaction was analyzed by using linear regression techniques. Stability was estimated using the Eberhart and Russell method. 'Kişlik Kirmizi51' was the most stable cultivar for grain yield. The highest protein was obtained from 'Kişlik Kirmizi51' (4.6%) across environments. According to stability analysis, 'Firat 87' had the most stable chemical composition. This genotype had a regression coefficient (b(i) = 1) around unity, and deviations from regression values (delta(ij) = 0) around zero. Chemical composition was affected by year in this study. Temperature might have an effect on protein, oil, carbohydrate, fibre and ash. Firat 87 could be recommended for favourable environments. Copyright (c) 2009 Society of Chemical Industry.

  1. Accelerating convergence in automatic lens design

    International Nuclear Information System (INIS)

    Brixner, B.

    1981-01-01

    Among the various factors that slow lens optimization-insufficient performance targets, the absence of a unique solution, false local minima, a poorly scaled change vector, failure to find the optimum damping number, and failure to equalize the parameter gradients-the importance of parameter gradient equalization has been insufficiently recognized. Gradients can be approximately equalized by scaling the lens to a suitable size while it is being optimized. For best results, the size of the damping number should also be optimized during each iteration. If these two procedures are followed, scaling the change vector is usually not crucial. To illustrate the importance of parameter equalization, a lens optimization is analyzed

  2. Nuclear magnetic resonance studies of lens transparency

    International Nuclear Information System (INIS)

    Beaulieu, C.F.

    1989-01-01

    Transparency of normal lens cytoplasm and loss of transparency in cataract were studied by nuclear magnetic resonance (NMR) methods. Phosphorus ( 31 P) NMR spectroscopy was used to measure the 31 P constituents and pH of calf lens cortical and nuclear homogenates and intact lenses as a function of time after lens enucleation and in opacification produced by calcium. Transparency was measured with laser spectroscopy. Despite complete loss of adenosine triphosphate (ATP) within 18 hrs of enucleation, the homogenates and lenses remained 100% transparent. Additions of calcium to ATP-depleted cortical homogenates produced opacification as well as concentration-dependent changes in inorganic phosphate, sugar phosphates, glycerol phosphorylcholine and pH. 1 H relaxation measurements of lens water at 200 MHz proton Larmor frequency studied temperature-dependent phase separation of lens nuclear homogenates. Preliminary measurements of T 1 and T 2 with non-equilibrium temperature changes showed a change in the slope of the temperature dependence of T 1 and T 2 at the phase separation temperature. Subsequent studies with equilibrium temperature changes showed no effect of phase separation on T 1 or T 2 , consistent with the phase separation being a low-energy process. 1 H nuclear magnetic relaxation dispersion (NMRD) studies (measurements of the magnetic field dependence of the water proton 1/T 1 relaxation rates) were performed on (1) calf lens nuclear and cortical homogenates (2) chicken lens homogenates, (3) native and heat-denatured egg white and (4) pure proteins including bovine γ-II crystallin bovine serum albumin (BSA) and myoglobin. The NMRD profiles of all samples exhibited decreases in 1/T 1 with increasing magnetic field

  3. Lubricant effects on low Dk and silicone hydrogel lens comfort.

    Science.gov (United States)

    Ozkan, Jerome; Papas, Eric

    2008-08-01

    To investigate the influence of three lubricants of varying viscosity, on postinsertion and 6 h comfort with contact lens wear. Comfort and associated symptoms of dryness were assessed in 15 experienced contact lens wearers. Subjects wore a low Dk lens in one eye and a silicone hydrogel in the other and participated in four separate trials involving no lubricant (baseline), saline, and two commercially available lubricants of differing viscosity. The in-eye lubricants were used immediately following lens insertion and every 2 h postinsertion for a 6 h wear period. Postlens insertion comfort was significantly better for both lens types when lubricants or saline were used compared with no lubricant use. After 6 h lens wear, comfort was influenced by lens type and not by in-eye lubricant or saline use. Also after 6 h lens wear, less dryness sensation was reported for silicone hydrogel lenses when using lubricants but not saline. Although lubricant use does help reduce dryness symptoms with silicone hydrogel lens wear, there appears to be minimal longer-term benefit to comfort. Furthermore, increased lubricant viscosity did not lead to improved longer-term comfort.

  4. Composite modified Luneburg model of human eye lens.

    Science.gov (United States)

    Gómez-Correa, J E; Balderas-Mata, S E; Pierscionek, B K; Chávez-Cerda, S

    2015-09-01

    A new lens model based on the gradient-index Luneburg lens and composed of two oblate half spheroids of different curvatures is presented. The spherically symmetric Luneburg lens is modified to create continuous isoindicial contours and to incorporate curvatures that are similar to those found in a human lens. The imaging capabilities of the model and the changes in the gradient index profile are tested for five object distances, for a fixed geometry and for a fixed image distance. The central refractive index decreases with decreasing object distance. This indicates that in order to focus at the same image distance as is required in the eye, a decrease in refractive power is needed for rays from closer objects that meet the lens surface at steeper angles compared to rays from more distant objects. This ensures a highly focused image with no spherical aberration.

  5. Focusing properties of a square electrostatic rainbow lens

    International Nuclear Information System (INIS)

    Telečki, I.; Petrović, S.; Beličev, P.; Rađenović, B.; Balvanović, R.; Bojović, B.; Nešković, N.

    2012-01-01

    This paper is devoted to the focusing properties of a square electrostatic rainbow lens, which is a novel ion beam optical element. We consider the transmission of parallel and non-parallel proton beams of the initial kinetic energy of 10 keV through this lens. The potential of the electrodes of the lens is chosen to be 2 kV. The electrostatic potential and components of the electric field in the region of the lens are calculated using a three-dimensional finite element computer code. We investigate the spatial and angular distributions of protons propagating through the lens and in the drift space after it. It is confirmed that the evolutions of these distributions are determined by the evolutions of the corresponding rainbow lines, generated using the theory of crystal rainbows. The beam is separated into two components. One beam component, appearing as a beam core, is generated dominantly by the focused protons. Its boundary line in the transverse position plane can be very well approximated by a hypotrochoid. The other beam component is generated dominantly by the defocused protons. We present the focusing coefficient of the lens, the confining coefficients of the lens for the focused and defocused protons, the density of the beam core, the vertical or horizontal emittance of the beam core, and the brightness of the beam core.

  6. A Class I UV-blocking (senofilcon A) soft contact lens prevents UVA-induced yellow fluorescence and NADH loss in the rabbit lens nucleus in vivo.

    Science.gov (United States)

    Giblin, Frank J; Lin, Li-Ren; Simpanya, Mukoma F; Leverenz, Victor R; Fick, Catherine E

    2012-09-01

    It is known that fluorescence, much of it caused by UVA light excitation, increases in the aging human lens, resulting in loss of sharp vision. This study used an in vivo animal model to investigate UVA-excited fluorescence in the rabbit lens, which contains a high level of the UVA chromophore NADH, existing both free and bound to λ-crystallin. Also, the ability of a Class I (senofilcon A) soft contact lens to protect against UVA-induced effects on the rabbit lens was tested. Rabbit eyes were irradiated with UVA light in vivo (100 mW/cm(2) on the cornea) for 1 h using monochromatic 365 nm light. Irradiation was conducted in the presence of either a senofilcon A contact lens, a minimally UV-absorbing lotrafilcon A contact lens, or no contact lens at all. Eyes irradiated without a contact lens showed blue 365 nm-excited fluorescence initially, but this changed to intense yellow fluorescence after 1 h. Isolated, previously irradiated lenses exhibited yellow fluorescence originating from the lens nucleus when viewed under 365 nm light, but showed normal blue fluorescence arising from the cortex. Previously irradiated lenses also exhibited a faint yellow color when observed under visible light. The senofilcon A contact lens protected completely against the UVA-induced effects on fluorescence and lens yellowing, whereas the lotrafilcon A lens showed no protection. The UVA-exposure also produced a 53% loss of total NADH (free plus bound) in the lens nucleus, with only a 13% drop in the anterior cortex. NADH loss in the nucleus was completely prevented with use of a senofilcon A contact lens, but no significant protection was observed with a lotrafilcon A lens. Overall, the senofilcon A lens provided an average of 67% protection against UVA-induced loss of four pyridine nucleotides in four different regions of the lens. HPLC analysis with fluorescence detection indicated a nearly six-fold increase in 365 nm-excited yellow fluorescence arising from lens nuclear

  7. Simultaneous distribution of AC and DC power

    Science.gov (United States)

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  8. Lens Model

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory of probabil...

  9. TESS Lens-Bezel Assembly Modal Testing

    Science.gov (United States)

    Dilworth, Brandon J.; Karlicek, Alexandra

    2017-01-01

    The Transiting Exoplanet Survey Satellite (TESS) program, led by the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MIT) will be the first-ever spaceborne all-sky transit survey. MIT Lincoln Laboratory is responsible for the cameras, including the lens assemblies, detector assemblies, lens hoods, and camera mounts. TESS is scheduled to be launched in August of 2017 with the primary goal to detect small planets with bright host starts in the solar neighborhood, so that detailed characterizations of the planets and their atmospheres can be performed. The TESS payload consists of four identical cameras and a data handling unit. Each camera consists of a lens assembly with seven optical elements and a detector assembly with four charge-coupled devices (CCDs) including their associated electronics. The optical prescription requires that several of the lenses are in close proximity to a neighboring element. A finite element model (FEM) was developed to estimate the relative deflections between each lens-bezel assembly under launch loads to predict that there are adequate clearances preventing the lenses from making contact. Modal tests using non-contact response measurements were conducted to experimentally estimate the modal parameters of the lens-bezel assembly, and used to validate the initial FEM assumptions. Key Words Non-contact measurements, modal analysis, model validation

  10. Isolation of MA-ACS Gene Family and Expression Study of MA-ACS1 Gene in Musa acuminata Cultivar Pisang Ambon Lumut

    Directory of Open Access Journals (Sweden)

    LISTYA UTAMI KARMAWAN

    2009-03-01

    Full Text Available Musa acuminata cultivar pisang ambon lumut is a native climacteric fruit from Indonesia. Climacteric fruit ripening process is triggered by the gaseous plant hormone ethylene. The rate limiting enzyme involved in ethylene biosynthesis is ACC synthase (ACS which is encoded by ACS gene family. The objective of this study is to identify MA-ACS gene family in M. acuminata cultivar pisang ambon lumut and to study the MA-ACS1 gene expression. The result showed that there were nine M. acuminata ACS gene family members called MA-ACS1–9. Two of them (MA-ACS1 and MA-ACS2 were assessed using reverse transcriptase PCR (RT-PCR for gene expression study and it was only MA-ACS1 correlated with fruit ripening. The MA-ACS1 gene fragment has been successfully isolated and characterized and it has three introns, four exons, and one stop codon. It also shows highest homology with MACS1 gene from M. acuminata cultivar Hsian Jien Chiao (GenBank accession number AF056164. Expression analysis of MA-ACS1 using quantitative PCR (qPCR showed that MA-ACS1 gene expression increased significantly in the third day, reached maximum at the fifth day, and then decreased in the seventh day after harvesting. The qPCR expression analysis result correlated with the result of physical analysis during fruit ripening.

  11. Surface Fourier-transform lens using a metasurface

    International Nuclear Information System (INIS)

    Li, Yun Bo; Cai, Ben Geng; Cheng, Qiang; Cui, Tie Jun

    2015-01-01

    We propose a surface (or 2D) Fourier-transform lens using a gradient refractive index (GRIN) metasurface in the microwave band, which is composed of sub-wavelength quasi-periodical metallic patches on a grounded dielectric substrate. Such a metasurface supports the transverse magnetic (TM) modes of surface waves. To gradually change the size of textures, we obtain different surface refractive indices, which can be tailored to fit the required refractive-index profile of a surface Fourier-transform lens. According to the theory of spatial Fourier transformation, we make use of the proposed lens to realize surface plane-wave scanning under different feeding locations. The simulation and experimental results jointly confirm the validity of the surface Fourier-transform lens. The proposed method can also be extended to the terahertz frequency. (paper)

  12. Universality of ac conduction in disordered solids

    DEFF Research Database (Denmark)

    Dyre, Jeppe; Schrøder, Thomas

    2000-01-01

    The striking similarity of ac conduction in quite different disordered solids is discussed in terms of experimental results, modeling, and computer simulations. After giving an overview of experiment, a macroscopic and a microscopic model are reviewed. For both models the normalized ac conductivity...... as a function of a suitably scaled frequency becomes independent of details of the disorder in the extreme disorder limit, i.e., when the local randomly varying mobilities cover many orders of magnitude. The two universal ac conductivities are similar, but not identical; both are examples of unusual non......-power-law universalities. It is argued that ac universality reflects an underlying percolation determining dc as well as ac conductivity in the extreme disorder limit. Three analytical approximations to the universal ac conductivities are presented and compared to computer simulations. Finally, model predictions...

  13. High-power rf pulse compression with SLED-II at SLAC

    International Nuclear Information System (INIS)

    Nantista, C.

    1993-04-01

    Increasing the peak rf power available from X-band microwave tubes by means of rf pulse compression is envisioned as a way of achieving the few-hundred-megawatt power levels needed to drive a next-generation linear collider with 50--100 MW klystrons. SLED-II is a method of pulse compression similar in principal to the SLED method currently in use on the SLC and the LEP injector linac. It utilizes low-los resonant delay lines in place of the storage cavities of the latter. This produces the added benefit of a flat-topped output pulse. At SLAC, we have designed and constructed a prototype SLED-II pulse-compression system which operates in the circular TE 01 mode. It includes a circular-guide 3-dB coupler and other novel components. Low-power and initial high-power tests have been made, yielding a peak power multiplication of 4.8 at an efficiency of 40%. The system will be used in providing power for structure tests in the ASTA (Accelerator Structures Test Area) bunker. An upgraded second prototype will have improved efficiency and will serve as a model for the pulse compression system of the NLCTA (Next Linear Collider Test Accelerator)

  14. THE SL2S GALAXY-SCALE LENS SAMPLE. II. COSMIC EVOLUTION OF DARK AND LUMINOUS MASS IN EARLY-TYPE GALAXIES

    International Nuclear Information System (INIS)

    Ruff, Andrea J.; Marshall, Philip J.; Treu, Tommaso; Auger, Matthew W.; Gavazzi, Raphael; Brault, Florence

    2011-01-01

    We present a joint gravitational lensing and stellar-dynamical analysis of 11 early-type galaxies (median deflector redshift z d = 0.5) from Strong Lenses in the Legacy Survey (SL2S). Using newly measured redshifts and stellar velocity dispersions from Keck spectroscopy with lens models from Paper I, we derive the total mass-density slope inside the Einstein radius for each of the 11 lenses. The average total density slope is found to be (γ') = 2.16 +0.09 -0.09 (ρ tot ∝r -γ ' ), with an intrinsic scatter of 0.25 +0.10 -0.07 . We also determine the dark matter fraction for each lens within half the effective radius, R eff /2, and find the average-projected dark matter mass fraction to be 0.42 +0.08 -0.08 with a scatter of 0.20 +0.09 -0.07 for a Salpeter initial mass function. By combining the SL2S results with those from the Sloan Lens ACS Survey (median z d = 0.2) and the Lenses Structure and Dynamics Survey (median z d = 0.8), we investigate cosmic evolution of γ' and find a mild trend ∂(γ')/∂z d = -0.25 +0.10 -0.12 . This suggests that the total density profile of massive galaxies has become slightly steeper over cosmic time. If this result is confirmed by larger samples, it would indicate that dissipative processes played some role in the growth of massive galaxies since z ∼ 1.

  15. The Correlation between Daily Lens Wear Duration and Dry Eye Syndrome.

    Science.gov (United States)

    Lubis, Rodiah Rahmawaty; Gultom, Monica Tumiar Hanna

    2018-05-20

    To analyze the correlation between the daily lens wear duration and dry eye syndrome. This study was an analytic cross sectional study using consecutive sampling conducted among the students in Economy and Bussiness Faculty and Faculty of Humanities in University of Sumatera Utara aged between 17 to 23 that wore contact lens continously for at least a year and 5 days a week. The symptoms were assessed using Contact Lens Dry Eye Questionnaire-8 (CLDEQ-8) and interview about their contact lens comfort; eye drops usage, contact lens washing habit, daily circumstances, places to buy contact lens and personal experince in wearing contact lens. The questionnaire was completed by 53 students. All of them were female and wore softlens wearers. The mean duration of daily wear was 8.19 ± 2.20 hours. The most common symptom experienced was dry eye and the least symptom experienced was removing lens. The most frequent symptom experienced was closing eyes and the least frequent symptom experienced was removing lenses. This study used Exact Test as analysis statistic method. The result was p > 0.05 which means there is no correlation between daily lens wear duration and dry eye syndrome. This study showed that dry eye syndrome was not correlated with daily lens wear duration, but affected by many factors such as contact lens, lens care solution, eye drops usage and environment.

  16. Measuring and correcting aberrations of a cathode objective lens

    International Nuclear Information System (INIS)

    Tromp, R.M.

    2011-01-01

    In this paper I discuss several theoretical and practical aspects related to measuring and correcting the chromatic and spherical aberrations of a cathode objective lens as used in Low Energy Electron Microscopy (LEEM) and Photo Electron Emission Microscopy (PEEM) experiments. Special attention is paid to the various components of the cathode objective lens as they contribute to chromatic and spherical aberrations, and affect practical methods for aberration correction. This analysis has enabled us to correct a LEEM instrument for the spherical and chromatic aberrations of the objective lens. -- Research highlights: → Presents a comprehensive theory of the relation between chromatic aberration and lens current in a cathode objective lens. → Presents practical methods for measuring both spherical and chromatic aberrations of a cathode objective lens. → Presents measurements of these aberrations in good agreement with theory. → Presents practical methods for measuring and correcting these aberrations with an electron mirror.

  17. Gravitational-Like Lens Based on Graphene Ripple.

    Science.gov (United States)

    Liu, Daqing; Chen, Shuyue; Ma, Ning; Zhao, Xiang; Xu, Zhuo

    2015-10-01

    We conducted a semiclassical study on carrier movement in curved graphene. A previous attempt was made to show that curved graphene is a readily available and cheap laboratory material used to study general relativity effects, especially if the electron energies satisfy 4μeV ≪ |E| ≪ 3eV. Furthermore, a gravitational-like lens can be constructed based on a special graphene ripple; this lens has neither chromatic nor cometic aberration. One can design an ideal electron lens using a graphene ripple.

  18. Gabor lens focusing of a negative ion beam

    International Nuclear Information System (INIS)

    Palkovic, J.A.; Mills, F.E.; Schmidt, C.; Young, D.E.

    1989-05-01

    Gabor or plasma lenses have previously been used to focus intense beams of positive ions at energies from 10 keV to 5 MeV. It is the large electrostatic field of the non-neutral plasma in the Gabor lens which is responsible for the focusing. Focusing an ion beam with a given sign of charge in a Gabor lens requires a non-neutral plasma with the opposite sign of charge as the beam. A Gabor lens constructed at Fermilab has been used to focus a 30 keV proton beam with good optical quality. We discuss studies of the action of a Gabor lens on a beam of negative ions. A Gabor lens has been considered for matching an H/sup /minus// beam into an RFQ in the redesign of the low energy section of the Fermilab linac. 9 refs., 3 figs., 1 tab

  19. Daily disposable contact lens prescribing around the world.

    Science.gov (United States)

    Efron, Nathan; Morgan, Philip B; Helland, Magne; Itoi, Motozumi; Jones, Deborah; Nichols, Jason J; van der Worp, Eef; Woods, Craig A

    2010-10-01

    Daily disposable contact lenses were introduced into the market 16 years ago. Data that we have gathered from annual contact lens fitting surveys conducted in Australia, Canada, Japan, The Netherlands, Norway, the UK and the USA between 2000 and 2008 indicates an overall increase in daily disposable lens fitting during this period. Daily disposable lenses are especially popular in Japan, Norway and the UK. There is a trend for these lenses to be fitted on a part-time basis. Males are over-represented in daily disposable lens fitting-a trend that is especially evident in Canada. Daily disposable lens wearers are about two years younger than wearers of reusable lenses in Japan and The Netherlands. The convenience and health benefits of daily disposable lenses are expected to fuel continued growth in this sector. Copyright (c) 2010 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  20. Committee Report of the BEPC-II Project Design Review May 13-15, 2002, SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Traci M.

    2002-08-26

    As part of the US-China Cooperative Program in High Energy Physics for the year 2002, a BEPC-II Upgrade Review meeting was held at SLAC, May 13-15, 2002. The upgrade is aimed at improving the luminosity and performance of the BEPC facility at IHEP in Beijing, China with major upgrades to the injector linac, storage ring, and detector. This review addresses mainly the accelerator related issues. Prior to the review, an updated Draft Design Report was made available to the review team. Most important technical change since April 2001 has been a change from a single-ring configuration to a doublering. The goal of the review is to determine whether BEPC-II, if built as described, will meet the operations and physics goals. The charge to the review team is attached as Appendix A.

  1. Pixel-based CTE Correction of ACS/WFC: Modifications To The ACS Calibration Pipeline (CALACS)

    Science.gov (United States)

    Smith, Linda J.; Anderson, J.; Armstrong, A.; Avila, R.; Bedin, L.; Chiaberge, M.; Davis, M.; Ferguson, B.; Fruchter, A.; Golimowski, D.; Grogin, N.; Hack, W.; Lim, P. L.; Lucas, R.; Maybhate, A.; McMaster, M.; Ogaz, S.; Suchkov, A.; Ubeda, L.

    2012-01-01

    The Advanced Camera for Surveys (ACS) was installed on the Hubble Space Telescope (HST) nearly ten years ago. Over the last decade, continuous exposure to the harsh radiation environment has degraded the charge transfer efficiency (CTE) of the CCDs. The worsening CTE impacts the science that can be obtained by altering the photometric, astrometric and morphological characteristics of sources, particularly those farthest from the readout amplifiers. To ameliorate these effects, Anderson & Bedin (2010, PASP, 122, 1035) developed a pixel-based empirical approach to correcting ACS data by characterizing the CTE profiles of trails behind warm pixels in dark exposures. The success of this technique means that it is now possible to correct full-frame ACS/WFC images for CTE degradation in the standard data calibration and reduction pipeline CALACS. Over the past year, the ACS team at STScI has developed, refined and tested the new software. The details of this work are described in separate posters. The new code is more effective at low flux levels (repair ACS electronics) and pixel-based CTE correction. In addition to the standard cosmic ray corrected, flat-fielded and drizzled data products (crj, flt and drz files) there are three new equivalent files (crc, flc and drc) which contain the CTE-corrected data products. The user community will be able to choose whether to use the standard or CTE-corrected products.

  2. UCLA accelerator research ampersand development. Progress report

    International Nuclear Information System (INIS)

    1997-01-01

    This report discusses work on advanced accelerators and beam dynamics at ANL, BNL, SLAC, UCLA and Pulse Sciences Incorporated. Discussed in this report are the following concepts: Wakefield acceleration studies; plasma lens research; high gradient rf cavities and beam dynamics studies at the Brookhaven accelerator test facility; rf pulse compression development; and buncher systems for high gradient accelerator and relativistic klystron applications

  3. A novel lens epithelium gene, LEP503, is highly conserved in different vertebrate species and is developmentally regulated in postnatal rat lens.

    Science.gov (United States)

    Wen, Y; Sachs, G; Athmann, C

    2000-02-01

    The development of the lens is dependent on the proliferation of lens epithelial cells and their differentiation into fiber cells near the lens bow/equator. Identification of genes specifically expressed in the lens epithelial cells and their functions may provide insight into molecular events that regulate the processes of lens epithelial cell differentiation. In this study, a novel lens epithelium gene product, LEP503, identified from rat by a subtractive cDNA cloning strategy was investigated in the genome organization, mRNA expression and protein localization. The genomic sequences for LEP503 isolated from rat, mouse and human span 1754 bp, 1694 bp and 1895 bp regions encompassing the 5'-flanking region, two exons, one intron and 3'-flanking region. All exon-intron junction sequences conform to the GT/AG rule. Both mouse and human LEP503 genes show very high identity (93% for mouse and 79% for human) to rat LEP503 gene in the exon 1 that contains an open reading frame coding for a protein of 61 amino acid residues with a leucine-rich domain. The deduced protein sequences also show high identity (91% between mouse and rat and 77% between human and rat). Western blot shows that LEP503 is present as a specific approximately 6.9 kDa band in the water-insoluble-urea-soluble fraction of lens cortex where lens epithelium is included. Immuno-staining shows that LEP503 is localized in the epithelial cells along the entire anterior surface of rat lens. Developmentally, LEP503 is expressed at a low level at newborn, and then the expression level increases by about ten-fold around postnatal day 14 and remains at this high level for about 25 days before it drops back to the low level by postnatal day 84. These data suggest that the LEP503 may be an important lens epithelial cell gene involving the processes of epithelial cell differentiation. Copyright 2000 Academic Press.

  4. A lazy way to design infrared lens

    Science.gov (United States)

    Qiu, RongSheng; Wu, JianDong; Chen, LongJiang; Yu, Kun; Pang, HaoJun; Hu, BaiZhen

    2017-08-01

    We designed a compact middle-wave infrared (MWIR) lens with a large focal length ratio (about 1.5:1), used in the 3.7 to 4.8 μm range. The lens is consisted of a compact front group and a re-imaging group. Thanks to the compact front group configuration, it is possible to install a filter wheel mechanism in such a tight space. The total track length of the lens is about 50mm, which includes a 2mm thick protective window and a cold shield of 12mm. The full field of view of the lens is about 3.6°, and F number is less than 1.6, the image circle is about 4.6mm in diameter. The design performance of the lens reaches diffraction limitation, and doesn't change a lot during a temperature range of -40°C +60°C. This essay proposed a stepwise design method of infrared optical system guided by the qualitative approach. The method fully utilize the powerful global optimization ability, with a little effort to write code snippet in optical design software, frees optical engineer from tedious calculation of the original structure.

  5. Passive performance monitoring and traffic characteristics on the SLAC internet border

    International Nuclear Information System (INIS)

    Logg, C.; Cottrell, L.

    2001-01-01

    Understanding how the Internet is used by HEP is critical to optimizing the performance of the inter-lab computing environment. Typically use requirements have been defined by discussions between collaborators. However, later analysis of the actual traffic has show this is often misunderstood and actual use is significantly different to that predicted. Passive monitoring of the real traffic provides insight into the true communications requirements and the performance of a large number of inter-communicating nodes. It may be useful in identifying performance problems that are due to factors other than Internet congestion, especially when compared to other methods such as active monitoring where traffic is generated specifically to measure its performance. Controlled active monitoring between dedicated servers often gives an indication of what can be achieved on a network. Passive monitoring of the real traffic gives a picture of the true performance. The authors will discuss the method and results of collecting and analyzing flows of data obtained from the SLAC Internet border. The insights this has brought to understanding the network will be reviewed and the benefit it can bring to engineering networks will be discussed

  6. AcMNPV

    African Journals Online (AJOL)

    USER

    2010-08-16

    Aug 16, 2010 ... biosynthesis pathway and plays an important role in insect growth and .... Construction and propagation of recombined AcMNPV. The recombined ... infected by virus increased with incubation time (Figure. 3). The growth of ...

  7. Modeling and reliability analysis of three phase z-source AC-AC converter

    Directory of Open Access Journals (Sweden)

    Prasad Hanuman

    2017-12-01

    Full Text Available This paper presents the small signal modeling using the state space averaging technique and reliability analysis of a three-phase z-source ac-ac converter. By controlling the shoot-through duty ratio, it can operate in buck-boost mode and maintain desired output voltage during voltage sag and surge condition. It has faster dynamic response and higher efficiency as compared to the traditional voltage regulator. Small signal analysis derives different control transfer functions and this leads to design a suitable controller for a closed loop system during supply voltage variation. The closed loop system of the converter with a PID controller eliminates the transients in output voltage and provides steady state regulated output. The proposed model designed in the RT-LAB and executed in a field programming gate array (FPGA-based real-time digital simulator at a fixedtime step of 10 μs and a constant switching frequency of 10 kHz. The simulator was developed using very high speed integrated circuit hardware description language (VHDL, making it versatile and moveable. Hardware-in-the-loop (HIL simulation results are presented to justify the MATLAB simulation results during supply voltage variation of the three phase z-source ac-ac converter. The reliability analysis has been applied to the converter to find out the failure rate of its different components.

  8. Contact Lens Related Corneal Ulcer

    OpenAIRE

    Loh, KY; Agarwal, P

    2010-01-01

    A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are: overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. Th...

  9. Adaptive Lens Inspired by Bio-Visual Systems

    National Research Council Canada - National Science Library

    Lo, Yu-Hwa

    2004-01-01

    ...: (a) We have identified and demonstrated the merits of PDMS elastomer for lens membranes. The PDMS-based fluidic lens process has been proven to be simple, controllable, and scalable to form lenses from 10 urn to several centimeters in diameter. (b...

  10. Multiocular image sensor with on-chip beam-splitter and inner meta-micro-lens for single-main-lens stereo camera.

    Science.gov (United States)

    Koyama, Shinzo; Onozawa, Kazutoshi; Tanaka, Keisuke; Saito, Shigeru; Kourkouss, Sahim Mohamed; Kato, Yoshihisa

    2016-08-08

    We developed multiocular 1/3-inch 2.75-μm-pixel-size 2.1M- pixel image sensors by co-design of both on-chip beam-splitter and 100-nm-width 800-nm-depth patterned inner meta-micro-lens for single-main-lens stereo camera systems. A camera with the multiocular image sensor can capture horizontally one-dimensional light filed by both the on-chip beam-splitter horizontally dividing ray according to incident angle, and the inner meta-micro-lens collecting the divided ray into pixel with small optical loss. Cross-talks between adjacent light field images of a fabricated binocular image sensor and of a quad-ocular image sensor are as low as 6% and 7% respectively. With the selection of two images from one-dimensional light filed images, a selective baseline for stereo vision is realized to view close objects with single-main-lens. In addition, by adding multiple light field images with different ratios, baseline distance can be tuned within an aperture of a main lens. We suggest the electrically selective or tunable baseline stereo vision to reduce 3D fatigue of viewers.

  11. Effects of x-irradiation on lens reducing systems. [Rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Giblin, F.J.; Chakrapani, B.; Reddy, V.N.

    1978-01-01

    Studies have been made of the effects of x ray on various lens reducing systems including the levels of NADPH and glutathione (GSH), the activity of the hexose monophosphate shunt (HMS), and the activities of certain enzymes including glutathion reductase, glutathione peroxidase, and glucose-6-phosphate dehydrogenase (G-6-PD). It was found that during several weeks following x irradiation but prior to cataract formation there was very little change in the number of reduced -SH groups per unit weight of lens protein but that, with the appearance of cataract, there was a sudden loss of protein -SH groups. In contrast, the concentration of GSH in the x-rayed lens decreased throughout the experimental period. Similarly, the concentration of NADPH in the x-rayed lens was found to decrease significantly relative to controls one week prior to cataract formation and the ratio of NADPH to NADP/sup +/ in the lens shifted at this time period from a value greater than 1.0 in the control lens to less than 1.0 in the x-rayed lens. A corresponding decrease occurred in the activity of the HMS in x-rayed lenses as measured by culture in the presence of 1-/sup 14/C-labelled glucose. G-6-PD was partially inactivated in the x-rayed lens. Of the eight enzymes studied, G-6-PD appeared to be the most sensitive to x-irradiation. The data indicate that x-irradiation results in a steady decrease in the effectiveness of lens reducing systems and that, when these systems reach a critically low point, sudden oxidation of protein -SH groups and formation of high molecular weight protein aggregates may be initiated.

  12. Active liquid-crystal deflector and lens with Fresnel structure

    Science.gov (United States)

    Shibuya, Giichi; Yamano, Shohei; Yoshida, Hiroyuki; Ozaki, Masanori

    2017-02-01

    A new type of tunable Fresnel deflector and lens composed of liquid crystal was developed. Combined structure of multiple interdigitated electrodes and the high-resistivity (HR) layer implements the saw-tooth distribution of electrical potential with only the planar surfaces of the transparent substrates. According to the numerical calculation and design, experimental devices were manufactured with the liquid crystal (LC) material sealed into the sandwiched flat glass plates of 0.7 mm thickness with rubbed alignment layers set to an anti-parallel configuration. Fabricated beam deflector with no moving parts shows the maximum tilt angle of +/-1.3 deg which can apply for optical image stabilizer (OIS) of micro camera. We also discussed and verified their lens characteristics to be extended more advanced applications. Transparent interdigitated electrodes were concentrically aligned on the lens aperture with the insulator gaps under their boundary area. The diameter of the lens aperture was 30 mm and the total number of Fresnel zone was 100. Phase retardation of the beam wavefront irradiated from the LC lens device can be evaluated by polarizing microscope images with a monochromatic filter. Radial positions of each observed fringe are plotted and fitted with 2nd degree polynomial approximation. The number of appeared fringes is over 600 in whole lens aperture area and the correlation coefficients of all approximations are over 0.993 that seems enough ideal optical wavefront. The obtained maximum lens powers from the approximations are about +/-4 m-1 which was satisfied both convex and concave lens characteristics; and their practical use for the tunable lens grade eyeglasses became more prospective.

  13. A Model of the Effect of Lens Development on Refraction in Schoolchildren.

    Science.gov (United States)

    He, Ji C

    2017-12-01

    The study provides a new theory on the mechanism underlying myopia development, and it could be useful in clinical practice to control myopia development in schoolchildren. To model the effect of the crystalline lens on refractive development in schoolchildren. The Zemax 13 was used to calculate Zernike aberrations and refractions across 50° horizontal visual fields. Optical effects of the anterior chamber depth, lens thickness, and radii of curvature of the lens surfaces on refractions were modeled. Refractive changes induced by lens development in emmetropic and myopic eyes, based on a previous longitudinal study from literature, were calculated. A lens thickness reduction with an anterior chamber depth deepening caused a hyperopic shift over the visual fields and even more at the periphery. Opposite effects were found when the lens was thinned without any change of the anterior chamber depth. While a flattening of the anterior lens surface produced hyperopic refractions overall, a posterior lens flattening caused a myopic shift at the periphery, but a hyperopic shift of the central refraction. In the myopic eye, lens development induced refractive change toward more hyperopic over the visual fields and more at the periphery. Lens thinning and lens axial movement participate in peripheral refractive development in schoolchildren, and lens development with a deeper anterior chamber depth and a flatter lens surface in the myopic eye could generate extra hyperopia over visual fields. The myopic lens development could be due to a backward movement of the lens, driven by a backward growth of the ciliary process, which might be a causative factor of myopia development.

  14. Approaches to building single-stage AC/AC conversion switch-mode audio power amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.; Andersen, Michael A.E.

    2005-07-01

    This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion will provide better efficiency and higher level of integration, leading to lower component count, volume and cost, but at the expense of a minor performance deterioration. (au)

  15. Proportional-Integral-Resonant AC Current Controller

    Directory of Open Access Journals (Sweden)

    STOJIC, D.

    2017-02-01

    Full Text Available In this paper an improved stationary-frame AC current controller based on the proportional-integral-resonant control action (PIR is proposed. Namely, the novel two-parameter PIR controller is applied in the stationary-frame AC current control, accompanied by the corresponding parameter-tuning procedure. In this way, the proportional-resonant (PR controller, common in the stationary-frame AC current control, is extended by the integral (I action in order to enable the AC current DC component tracking, and, also, to enable the DC disturbance compensation, caused by the voltage source inverter (VSI nonidealities and by nonlinear loads. The proposed controller parameter-tuning procedure is based on the three-phase back-EMF-type load, which corresponds to a wide range of AC power converter applications, such as AC motor drives, uninterruptible power supplies, and active filters. While the PIR controllers commonly have three parameters, the novel controller has two. Also, the provided parameter-tuning procedure needs only one parameter to be tuned in relation to the load and power converter model parameters, since the second controller parameter is directly derived from the required controller bandwidth value. The dynamic performance of the proposed controller is verified by means of simulation and experimental runs.

  16. Particle swarm optimization applied to automatic lens design

    Science.gov (United States)

    Qin, Hua

    2011-06-01

    This paper describes a novel application of Particle Swarm Optimization (PSO) technique to lens design. A mathematical model is constructed, and merit functions in an optical system are employed as fitness functions, which combined radiuses of curvature, thicknesses among lens surfaces and refractive indices regarding an optical system. By using this function, the aberration correction is carried out. A design example using PSO is given. Results show that PSO as optical design tools is practical and powerful, and this method is no longer dependent on the lens initial structure and can arbitrarily create search ranges of structural parameters of a lens system, which is an important step towards automatic design with artificial intelligence.

  17. Transglutaminase involvement in UV-A damage to the eye lens

    International Nuclear Information System (INIS)

    Weinreb, Orly; Dovrat, A.

    1996-01-01

    Solar radiation is believed to be one of the major environmental factors involved in lens cataractogenesis. The purpose of the study was to investigate the mechanisms by which UV-A at 365 nm causes damage to the eye lens. Bovine lenses were placed in special culture cells for pre-incubation of 24 hr. The lenses were positioned so that the anterior surface faced the incident UV-A radiation source and were maintained in the cells during irradiation. After irradiation, lens optical quality was monitored throughout the culture period and lens epithelium, cortex and nuclear samples were taken for biochemical analysis. Transglutaminase activity in the lens was affected by the radiation. The activity of transglutaminase in lens epithelium cortex and nucleus increased as a result of the irradiation and then declined towards control levels during the culture period, as the lens recovered from the UV-A damage. Specific lens proteins αB and βB1 crystallins (the enzyme substrates) were analyzed by SDS polyacrylamid gel electrophoreses and immunoblotting with specific antibodies. Seventy-two hours after irradiation of 44.8 J cm -2 UV-A, αB crystallins were affected as was shown by the appearance of aggregation and degradation products. Some protein changes seem to be reversible. It appears that transglutaminase may be involved in the mechanism by which UV-A causes damage to the eye lens. (Author)

  18. Integrated Lens Antennas for Multi-Pixel Receivers

    Science.gov (United States)

    Lee, Choonsup; Chattopadhyay, Goutam

    2011-01-01

    Future astrophysics and planetary experiments are expected to require large focal plane arrays with thousands of detectors. Feedhorns have excellent performance, but their mass, size, fabrication challenges, and expense become prohibitive for very large focal plane arrays. Most planar antenna designs produce broad beam patterns, and therefore require additional elements for efficient coupling to the telescope optics, such as substrate lenses or micromachined horns. An antenna array with integrated silicon microlenses that can be fabricated photolithographically effectively addresses these issues. This approach eliminates manual assembly of arrays of lenses and reduces assembly errors and tolerances. Moreover, an antenna array without metallic horns will reduce mass of any planetary instrument significantly. The design has a monolithic array of lens-coupled, leaky-wave antennas operating in the millimeter- and submillimeter-wave frequencies. Electromagnetic simulations show that the electromagnetic fields in such lens-coupled antennas are mostly confined in approximately 12 15 . This means that one needs to design a small-angle sector lens that is much easier to fabricate using standard lithographic techniques, instead of a full hyper-hemispherical lens. Moreover, this small-angle sector lens can be easily integrated with the antennas in an array for multi-pixel imager and receiver implementation. The leaky antenna is designed using double-slot irises and fed with TE10 waveguide mode. The lens implementation starts with a silicon substrate. Photoresist with appropriate thickness (optimized for the lens size) is spun on the substrate and then reflowed to get the desired lens structure. An antenna array integrated with individual lenses for higher directivity and excellent beam profile will go a long way in realizing multi-pixel arrays and imagers. This technology will enable a new generation of compact, low-mass, and highly efficient antenna arrays for use in multi

  19. Mathematical Lens: How Much Can You Bench?

    Science.gov (United States)

    Bolognese, Chris A.

    2013-01-01

    "How Much Can You Bench?" appears in the "Mathematical Lens" section of "Mathematics Teacher." "Mathematical Lens" uses photographs as a springboard for mathematical inquiry and appears in every issue of "Mathematics Teacher." This month the mathematics behind the photograph includes finding areas…

  20. Bacterial transmission from lens storage cases to contact lenses - Effects of lens care solutions and silver impregnation of cases

    NARCIS (Netherlands)

    Vermeltfoort, Pit B. J.; Hooymans, Johanna M. M.; Busscher, Henk J.; van der Mei, Henny C.

    2008-01-01

    The killing efficacies of multipurpose lens care solutions on planktonic and biofilm bacteria grown in polypropylene contact lens storage cases with and without silver impregnation and effects on bacterial transmission from storage cases to silicone hydrogel contact lenses were investigated. For

  1. Piggyback intraocular lens implantation to correct pseudophakic refractive error after segmental multifocal intraocular lens implantation.

    Science.gov (United States)

    Venter, Jan A; Oberholster, Andre; Schallhorn, Steven C; Pelouskova, Martina

    2014-04-01

    To evaluate refractive and visual outcomes of secondary piggyback intraocular lens implantation in patients diagnosed as having residual ametropia following segmental multifocal lens implantation. Data of 80 pseudophakic eyes with ametropia that underwent Sulcoflex aspheric 653L intraocular lens implantation (Rayner Intraocular Lenses Ltd., East Sussex, United Kingdom) to correct residual refractive error were analyzed. All eyes previously had in-the-bag zonal refractive multifocal intraocular lens implantation (Lentis Mplus MF30, models LS-312 and LS-313; Oculentis GmbH, Berlin, Germany) and required residual refractive error correction. Outcome measurements included uncorrected distance visual acuity, corrected distance visual acuity, uncorrected near visual acuity, distance-corrected near visual acuity, manifest refraction, and complications. One-year data are presented in this study. The mean spherical equivalent ranged from -1.75 to +3.25 diopters (D) preoperatively (mean: +0.58 ± 1.15 D) and reduced to -1.25 to +0.50 D (mean: -0.14 ± 0.28 D; P < .01). Postoperatively, 93.8% of eyes were within ±0.50 D and 98.8% were within ±1.00 D of emmetropia. The mean uncorrected distance visual acuity improved significantly from 0.28 ± 0.16 to 0.01 ± 0.10 logMAR and 78.8% of eyes achieved 6/6 (Snellen 20/20) or better postoperatively. The mean uncorrected near visual acuity changed from 0.43 ± 0.28 to 0.19 ± 0.15 logMAR. There was no significant change in corrected distance visual acuity or distance-corrected near visual acuity. No serious intraoperative or postoperative complications requiring secondary intraocular lens removal occurred. Sulcoflex lenses proved to be a predictable and safe option for correcting residual refractive error in patients diagnosed as having pseudophakia. Copyright 2014, SLACK Incorporated.

  2. Effects of Coupling Lens on Optical Refrigeration of Semiconductors

    International Nuclear Information System (INIS)

    Kai, Ding; Yi-Ping, Zeng

    2008-01-01

    Optical refrigeration of semiconductors is encountering efficiency difficulties caused by nonradiative recombination and luminescence trapping. A commonly used approach for enhancing luminescence efficiency of a semiconductor device is coupling a lens with the device. We quantitatively study the effects of a coupling lens on optical refrigeration based on rate equations and photon recycling, and calculated cooling efficiencies of different coupling mechanisms and of different lens materials. A GaAs/GaInP heterostructure coupled with a homo-epitaxial GaInP hemispherical lens is recommended. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  3. Single lens laser beam shaper

    Science.gov (United States)

    Liu, Chuyu [Newport News, VA; Zhang, Shukui [Yorktown, VA

    2011-10-04

    A single lens bullet-shaped laser beam shaper capable of redistributing an arbitrary beam profile into any desired output profile comprising a unitary lens comprising: a convex front input surface defining a focal point and a flat output portion at the focal point; and b) a cylindrical core portion having a flat input surface coincident with the flat output portion of the first input portion at the focal point and a convex rear output surface remote from the convex front input surface.

  4. Analytic models of plausible gravitational lens potentials

    International Nuclear Information System (INIS)

    Baltz, Edward A.; Marshall, Phil; Oguri, Masamune

    2009-01-01

    Gravitational lenses on galaxy scales are plausibly modelled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sérsic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasising that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential. We also provide analytic formulae for the lens potentials of Sérsic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modelled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses

  5. ANALYTICAL SOLUTIONS OF SINGULAR ISOTHERMAL QUADRUPOLE LENS

    International Nuclear Information System (INIS)

    Chu Zhe; Lin, W. P.; Yang Xiaofeng

    2013-01-01

    Using an analytical method, we study the singular isothermal quadrupole (SIQ) lens system, which is the simplest lens model that can produce four images. In this case, the radial mass distribution is in accord with the profile of the singular isothermal sphere lens, and the tangential distribution is given by adding a quadrupole on the monopole component. The basic properties of the SIQ lens have been studied in this Letter, including the deflection potential, deflection angle, magnification, critical curve, caustic, pseudo-caustic, and transition locus. Analytical solutions of the image positions and magnifications for the source on axes are derived. We find that naked cusps will appear when the relative intensity k of quadrupole to monopole is larger than 0.6. According to the magnification invariant theory of the SIQ lens, the sum of the signed magnifications of the four images should be equal to unity, as found by Dalal. However, if a source lies in the naked cusp, the summed magnification of the left three images is smaller than the invariant 1. With this simple lens system, we study the situations where a point source infinitely approaches a cusp or a fold. The sum of the magnifications of the cusp image triplet is usually not equal to 0, and it is usually positive for major cusps while negative for minor cusps. Similarly, the sum of magnifications of the fold image pair is usually not equal to 0 either. Nevertheless, the cusp and fold relations are still equal to 0 in that the sum values are divided by infinite absolute magnifications by definition.

  6. CONTACT LENS RELATED CORNEAL ULCER

    Directory of Open Access Journals (Sweden)

    AGARWAL P

    2010-01-01

    Full Text Available A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are:overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. The presenting symptoms of contact lens related corneal ulcers include eye discomfort, foreign body sensation and lacrimation. More serious symptoms are redness (especially circum-corneal injection, severe pain, photophobia, eye discharge and blurring of vision. The diagnosis is established by a thorough slit lamp microscopic examination with fluorescein staining and corneal scraping for Gram stain and culture of the infective organism. Delay in diagnosing and treatment can cause permanent blindness, therefore an early referral to ophthalmologist and commencing of antimicrobial therapy can prevent visual loss.

  7. Low ac loss geometries in YBCO coated conductors

    International Nuclear Information System (INIS)

    Duckworth, R.C.; List, F.A.; Paranthaman, M.P.; Rupich, M.W.; Zhang, W.; Xie, Y.Y.; Selvamanickam, V.

    2007-01-01

    Reduction of ac losses in applied ac fields can be accomplished through either the creation of filaments and bridging in YBCO coated conductors or by an assembly of narrow width YBCO tapes. The ac losses for each of these geometries were measured at 77 K in perpendicular ac fields up to 100 mT. Despite physical isolation of the filaments, coupling losses were still present in the samples when compared to the expected hysteretic loss. In addition to filamentary conductors the assembly of stacked YBCO conductor provides an alternative method of ac loss reduction. When compared to a 4-mm wide YBCO coated conductor with a critical current of 60 A, the ac loss in a stack of 2-mm wide YBCO coated conductors with a similar total critical current was reduced. While the reduction in ac loss in a 2-mm wide stack coincided with the reduction in the engineering current density of the conductor, further reduction of ac loss was obtained through the splicing of the 2-mm wide tapes with low resistance solders

  8. Low ac loss geometries in YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Duckworth, R.C. [Oak Ridge National Laboratory, One Bethel Valley Road, P.O. Box 2008, MS-6305, Oak Ridge, TN 37831-6305 (United States)], E-mail: duckworthrc@ornl.gov; List, F.A.; Paranthaman, M.P. [Oak Ridge National Laboratory, One Bethel Valley Road, P.O. Box 2008, MS-6305, Oak Ridge, TN 37831-6305 (United States); Rupich, M.W.; Zhang, W. [American Superconductor, Two Technology Drive, Westborough, MA 01581 (United States); Xie, Y.Y.; Selvamanickam, V. [SuperPower, 450 Duane Ave, Schenectady, NY 12304 (United States)

    2007-10-01

    Reduction of ac losses in applied ac fields can be accomplished through either the creation of filaments and bridging in YBCO coated conductors or by an assembly of narrow width YBCO tapes. The ac losses for each of these geometries were measured at 77 K in perpendicular ac fields up to 100 mT. Despite physical isolation of the filaments, coupling losses were still present in the samples when compared to the expected hysteretic loss. In addition to filamentary conductors the assembly of stacked YBCO conductor provides an alternative method of ac loss reduction. When compared to a 4-mm wide YBCO coated conductor with a critical current of 60 A, the ac loss in a stack of 2-mm wide YBCO coated conductors with a similar total critical current was reduced. While the reduction in ac loss in a 2-mm wide stack coincided with the reduction in the engineering current density of the conductor, further reduction of ac loss was obtained through the splicing of the 2-mm wide tapes with low resistance solders.

  9. Combined 23-gauge transconjunctival vitrectomy and scleral fixation of intraocular lens without conjunctival dissection in managing lens complications.

    Science.gov (United States)

    Yeung, Ling; Wang, Nan-Kai; Wu, Wei-Chi; Chen, Kuan-Jen

    2018-04-23

    To evaluate the safety and efficacy of combined 23-gauge transconjunctival pars plana vitrectomy and scleral fixation of intraocular lens (IOL) without conjunctival dissection. A retrospective study in Chang Gung Memorial Hospital, Keelung and Taoyuan, Taiwan. Patients receiving combined 23-gauge transconjunctival pars plana vitrectomy and scleral fixation of IOL without conjunctival dissection were enrolled. The ocular findings, causes of lens complication, surgical procedures, type of IOL used, and complications were documented. We included 40 eyes from 39 patients (27 male, 12 female) with a mean age of 59.5 [standard deviation (±) 14.8] years old. The mean follow-up duration was 6.8 ± 5.4 months. The cause of lens complications was ocular trauma in 24 (60%) eyes, cataract surgery complications in 11 (28%) eyes, and spontaneous subluxation of crystalline lens in 5 (13%) eyes. The overall best corrected visual acuity (BCVA) (logMAR) improved from 1.359 ± 0.735 to 0.514 ± 0.582 (p IOL decentration was found in 3 (8%) eyes and 1 (3%) eye respectively. Combined 23-gauge transconjunctival vitrectomy and scleral fixation of IOL without conjunctival dissection is effective and safe in managing a wide variety of lens complications, with good postoperative comfort and visual recovery. Retrospective study, not applicable.

  10. Research and development toward a 4.5-1.5{angstrom} linac coherent light source (LCLS) at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Tatchyn, R.; Arthur, J.; Baltay, M. [Stanford Univ., CA (United States)] [and others

    1995-12-31

    In recent years significant studies have been initiated on the theoretical and technical feasibility of utilizing a portion of the 3km S-band accelerator at the Stanford Linear Accelerator Center (SLAC) to drive a short wavelength (4.5-1.5 {Angstrom}) Linac Coherent Light Source (LCLS), a Free-Electron Laser (FEL) operating in the Self-Amplified Spontaneous Emission (SASE) regime. Electron beam requirements for single-pass saturation include: (1) a peak current in the 3-7 kA range, (2) a relative energy spread of <0.05%, ad (3) a transverse emittance, {epsilon}{le}{lambda}/4{pi}, where {lambda}[m] is the output wavelength. Requirements on the insertion device include field error levels of 0.1-0.2% for keeping the electron bunch centered on and in phase with the amplified photons, and a focusing beta of 4-8 m for inhibiting the dilution of its transverse density. Although much progress techniques necessary for LCLS operation down to {approximately}20 {angstrom}, a substantial amount of research and development is still required in a number of theoretical and experimental areas leading to the construction and operation of a 4.5-1.5 {angstrom} LCLS. In this paper we report on a research and development program underway and in planning at SLAC for addressing critical questions in these areas. These include the construction and operation of a linac test stand for developing laser-driven photocathode rf guns with normalized emittances approaching 1 mm-mr; development of advanced beam compression, stability, an emittance control techniques at multi-GeV energies; the construction and operation of a FEL Amplifier Test Experiment (FATE) for theoretical and experimental studies of SASE at IR wavelengths; an undulator development program to investigate superconducting, hybrid/permanent magnet (hybrid/PM), and pulsed-Cu technologies; theoretical and computational studies of high-gain FEL physics and LCLS component designs.

  11. Tunable Focus Liquid Lens with Radial-Patterned Electrode

    Directory of Open Access Journals (Sweden)

    Miao Xu

    2015-08-01

    Full Text Available A dielectric liquid lens is prepared based on our previous work. By optimizing the device structure, the liquid lens presents a converging focus with good resolution and changes its focal length over a broad range with a low driving voltage. For a liquid lens with ~2.3 mm diameter in the relaxed state, it can resolve ~40 lp/mm. The resolution does not degrade during focus change. Its focal length can be varied from ~12 to ~5 mm when the applied voltage is changed from 0 to 28 Vrms. The response time of one cycle is ~2.5 s. Our liquid lens, with a low driving voltage for a large dynamic range, has potential applications in imaging, biometrics, optoelectronic, and lab-on-chip devices.

  12. Development of a Laue lens for nuclear astrophysics

    International Nuclear Information System (INIS)

    Barriere, N.

    2008-04-01

    The Laue lenses we study focuses in the domain of 0.1-1 MeV thanks to Bragg diffraction in the volume of a large number of small crystal tiles. The focal length of a typical Laue lens system is of the order of 100 m. This requirement calls for two formation flying satellites maintaining lens and detector at the focal distance. The major breakthrough of Laue lenses is to decouple collecting area from detector area. Concentrating a signal from the large area of a Laue lens onto a small focal spot dramatically increases the signal over background ratio with respect to present technologies. Here is the reason for the long awaited leap in sensitivity. The objective of the present thesis was to improve the concept, finding viable technical solutions towards a future space mission. Two aspects of the lens development have been highlighted in this thesis: the first one is an analytical model of the lens that is used to calculate and improve the performance of a certain configuration, the second aspect concerns the search and the characterization of diffracting media of interest. The lens model developed relies on a fast semi-analytical simulation library, permitting to build several design- and optimisation-tools. For the configuration of a given lens, this code computes the resulting effective area and point spread function in a handful of seconds. The model helps finding lens configurations (mass, pack ratio of the lens rings,...) which are automatically refined to match with effective area and energy coverage constraints. These tools have been used to investigate various design aspects, such as the influence of focal length, size, mosaic spread, structure and materials of crystals, etc... The central evaluation criterion in the model is a figure of merit, based on the compactness of the focal spot and the intensity of the collected signal. The second part of this work addresses the actual search and characterization of crystals potentially interesting for Laue lenses

  13. TU-E-201-02: Eye Lens Dosimetry From CT Perfusion Studies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D. [Toshiba America Medical Systems (United States)

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  14. TU-E-201-00: Eye Lens Dosimetry for Patients and Staff

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  15. TU-E-201-02: Eye Lens Dosimetry From CT Perfusion Studies

    International Nuclear Information System (INIS)

    Zhang, D.

    2015-01-01

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  16. TU-E-201-00: Eye Lens Dosimetry for Patients and Staff

    International Nuclear Information System (INIS)

    2015-01-01

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  17. Recent SLAC measurements of the spin dependent structure functions for the proton and neutron

    International Nuclear Information System (INIS)

    Zapalac, G.

    1995-09-01

    The authors present results from SLAC experiments E142 and E143 for the spin dependent structure functions of the proton g 1 p (x, Q 2 ) and neutron g 1 n (x,Q 2 ) measured in deep inelastic scattering of polarized electrons from a polarized target. Experiment E142 measures ∫ 0 1 g 1 n (x)dx = -0.022 ± 0.011 at 2 > = 2 (GeV/c) 2 using a polarized 3 He target. Experiment E143 measures ∫ 0 1 g 1 p (x)dx = 0.129 ± 0.011 at 2 > = 3 (GeV/c) 2 using a polarized NH 3 target. These results are combined at Q 2 = 3 (GeV/c) 2 to yield ∫ 0 1 [g 1 p (x) - g 1 n (x)]dx = 0.151 ± 0.015. The Bjorken sum rule predicts 0.171 ± 0.008

  18. Calpain expression and activity during lens fiber cell differentiation.

    Science.gov (United States)

    De Maria, Alicia; Shi, Yanrong; Kumar, Nalin M; Bassnett, Steven

    2009-05-15

    In animal models, the dysregulated activity of calcium-activated proteases, calpains, contributes directly to cataract formation. However, the physiological role of calpains in the healthy lens is not well defined. In this study, we examined the expression pattern of calpains in the mouse lens. Real time PCR and Western blotting data indicated that calpain 1, 2, 3, and 7 were expressed in lens fiber cells. Using controlled lysis, depth-dependent expression profiles for each calpain were obtained. These indicated that, unlike calpain 1, 2, and 7, which were most abundant in cells near the lens surface, calpain 3 expression was strongest in the deep cortical region of the lens. We detected calpain activities in vitro and showed that calpains were active in vivo by microinjecting fluorogenic calpain substrates into cortical fiber cells. To identify endogenous calpain substrates, membrane/cytoskeleton preparations were treated with recombinant calpain, and cleaved products were identified by two-dimensional difference electrophoresis/mass spectrometry. Among the calpain substrates identified by this approach was alphaII-spectrin. An antibody that specifically recognized calpain-cleaved spectrin was used to demonstrate that spectrin is cleaved in vivo, late in fiber cell differentiation, at or about the time that lens organelles are degraded. The generation of the calpain-specific spectrin cleavage product was not observed in lens tissue from calpain 3-null mice, indicating that calpain 3 is uniquely activated during lens fiber differentiation. Our data suggest a role for calpains in the remodeling of the membrane cytoskeleton that occurs with fiber cell maturation.

  19. Contact lens wear and dry eyes: challenges and solutions

    Directory of Open Access Journals (Sweden)

    Markoulli M

    2017-02-01

    Full Text Available Maria Markoulli, Sailesh Kolanu School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia Abstract: The number of contact lens wearers worldwide has remained relatively stable over the past decade, despite the investment that has gone into contact lens technology. This is largely because 10%–50% of wearers dropout of contact lens wear within 3 years of commencement; the most common reason cited being contact lens discomfort (CLD. Of the symptoms reported, sensation of dry eye is the most common. Given the outcome of reduced wearing time, increased chair time, and ultimate contact lens discontinuation, the challenge is to identify the warning signs of CLD early on. Clinically detectable changes such as conjunctival staining, conjunctival indentation, conjunctival epithelial flap formation, lid wiper epitheliopathy, Demodex blepharitis, and meibomian gland dysfunction have been linked to CLD, highlighting the need to perform regular aftercare visits to identify these changes. At a cellular level, conjunctival metaplasia and reduced goblet cell density have been linked to CLD, leading to a downstream effect on the tear film breakup time of contact lens wearers. These factors suggest a strong link between CLD and friction, raising the need to target this as a means of minimizing CLD. The purpose of this review is to identify the clinical signs that relate to CLD as a means of earlier detection and management in order to combat contact lens dropout. Keywords: contact lens discomfort, dry eye disease, lid wiper epitheliopathy, tear film biomarkers, meibomian gland dysfunction

  20. Customer loyalty among daily disposable contact lens wearers.

    Science.gov (United States)

    Patel, Neelam I; Naroo, Shehzad A; Eperjesi, Frank; Rumney, Nicholas J

    2015-02-01

    Optometric practices offer contact lenses as cash sale items or as part of monthly payment plans. With the contact lens market becoming increasingly competitive, patients are opting to purchase lenses from supermarkets and Internet suppliers. Monthly payment plans are often implemented to improve loyalty. This study aimed to compare behavioural loyalty between monthly payment plan members and non-members. BBR Optometry Ltd offers a monthly payment plan (Eyelife™) to their contact lens wearers. A retrospective audit of 38 Eyelife™ members (mean±SD: 42.7±15.0 years) and 30 non-members (mean±SD: 40.8±16.7 years) was conducted. Revenue and profits generated, service uptake and product sales between the two groups were compared over a fixed period of 18 months. Eyelife™ members generated significantly higher professional fee revenue (Ployalty among contact lens wearers, particularly service uptake and volume of lens purchases. Additionally the greater professional fees generated, render monthly payment plans an attractive business model and practice builder. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  1. Design of LED projector based on gradient-index lens

    Science.gov (United States)

    Qian, Liyong; Zhu, Xiangbing; Cui, Haitian; Wang, Yuanhang

    2018-01-01

    In this study, a new type of projector light path is designed to eliminate the deficits of existing projection systems, such as complex structure and low collection efficiency. Using a three-color LED array as the lighting source, by means of the special optical properties of a gradient-index lens, the complex structure of the traditional projector is simplified. Traditional components, such as the color wheel, relay lens, and mirror, become unnecessary. In this way, traditional problems, such as low utilization of light energy and loss of light energy, are solved. With the help of Zemax software, the projection lens is optimized. The optimized projection lens, LED, gradient-index lens, and digital micromirror device are imported into Tracepro. The ray tracing results show that both the utilization of light energy and the uniformity are improved significantly.

  2. AC conductivity and dielectric behavior of bulk Furfurylidenemalononitrile

    Science.gov (United States)

    El-Nahass, M. M.; Ali, H. A. M.

    2012-06-01

    AC conductivity and dielectric behavior for bulk Furfurylidenemalononitrile have been studied over a temperature range (293-333 K) and frequency range (50-5×106 Hz). The frequency dependence of ac conductivity, σac, has been investigated by the universal power law, σac(ω)=Aωs. The variation of the frequency exponent (s) with temperature was analyzed in terms of different conduction mechanisms, and it was found that the correlated barrier hopping (CBH) model is the predominant conduction mechanism. The temperature dependence of σac(ω) showed a linear increase with the increase in temperature at different frequencies. The ac activation energy was determined at different frequencies. Dielectric data were analyzed using complex permittivity and complex electric modulus for bulk Furfurylidenemalononitrile at various temperatures.

  3. [Lens luxation in dogs: a retrospective study of 134 dogs (2000-2011)].

    Science.gov (United States)

    Betschart; Hässig; Spiess

    2014-03-01

    This retrospective study evaluated cases of lens luxation in dogs that were documented at the University of Zurich Veterinary Teaching Hospital between 2000 and 2011. A total 134 dogs were included in the study. This population of dogs with lens luxation represents 0.41 % of all dogs presented to the Zurich Veterinary Teaching Hospital (32'523) and 3.02 % of all dogs presented to the ophthalmology service during the same time period. The 134 dogs represented over 40 different breeds, including mixed breeds. 63 of the dogs were male, 71 were female. The 134 dogs were divided in primary lens luxation (86 of the 134 dogs, 64 %) and secondary lens luxation (48 dogs, 36 %). The most frequent causes for secondary lens luxation were glaucoma (58 %), cataract (19 %) and trauma (17 %). This study shows the predisposition for primary lens luxations in terrier breeds, Chinese Crested dogs, Pinscher and Spitz. In contrast, Siberian Huskies, Basset Hounds, Bearded Collies, Cairn Terriers, mixed breed dogs, Bolonka Zwetna, Boston Terriers, Borzoi, Doberman, Eurasian, Leonberg, Luzerner Niederlaufhund and Weimaraner suffered significantly more often from secondary lens luxation. There was no sex predilection for primary or secondary lens luxation. Dogs with primary lens luxation were on average 7.39 ± 3.02 years old, which is significantly younger than the dogs with secondary lens luxation (9.12 ± 3.38 years). Dogs with primary lens luxation showed a significantly higher rate of a bilateral development than those with secondary lens luxation (85.5 % of the dogs with primary lens luxation and only 14.5 % of the dogs with secondary lens luxation showed it in both their eyes).

  4. Applanation tonometry in silicone hydrogel contact lens wearers.

    Science.gov (United States)

    Allen, R J; Dev Borman, A; Saleh, G M

    2007-12-01

    Previous studies have investigated intraocular pressure (IOP) measurements through conventional soft (hydrogel) therapeutic contact lenses, and have found that an accurate IOP can be recorded in normal eyes, and in eyes with abnormal anterior segments. The IOP measurement through soft contact lenses may be affected by the water content and centre thickness of the lens. Silicone hydrogel contact lenses are now being used as therapeutic contact lenses due to their high oxygen permeability. The purpose of this study is to investigate if IOP can be accurately measured in a subject wearing a silicone hydrogel contact lens. In a cohort study, the IOP was measured with a Goldmann applanation tonometer without a contact lens and then repeated with a hydrogel contact lens in situ. The IOP of 20 eyes of 10 volunteers with no ocular pathology was measured. The mean difference (+/-S.D.) found between IOP measurement with (mean 15.55+/-1.70 mmHg) and without (mean 16.05+/-1.90 mmHg) contact lens was found to be -0.5+/-0.89 mmHg. Statistical analysis was performed which revealed a correlation coefficient of 0.89. No significant statistical difference was found between the two groups with paired t-test (p=0.19). Accurate measurement of IOP by applanation tonometry can be achieved through a silicone hydrogel contact lens.

  5. Dark secrets behind the shimmer of contact lens: the Indian scenario

    Directory of Open Access Journals (Sweden)

    Singh Deepak

    2009-05-01

    Full Text Available Abstract Background We studied the bacteriological profile of soft contact lens and its accessories among the asymptomatic subjects and monitored the compliance level with the lens use and its cleaning protocol. Findings A total of 115 (104 daily wear and 11 extended wear subjects using contact lens were studied. Data regarding the duration of use and frequency and method of cleaning were recorded. Contact lens, lens cases, preserving solutions and tips of solution bottles were the samples collected. The isolates were identified on the basis of their phenotypic characters. Samples from 24 subjects (21 daily wear and 3 extended wear were found contaminated. Of the 24 contaminated cases, 23 showed medium adherence to the cleaning protocol. Contamination rate was higher among the 56 daily wear lens users who used same lens for 2 years and more, than the 48 users who used their lenses for less than 2 years. Lens case contamination was found in all the 24 cases. The bacteria isolated were Citrobacter freundii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus epidermidis and Streptococcus pneumoniae. In extended wear lens users, there was no change in microbial flora on repeating the cultures on day 7 and 14. Conclusion Non-compliance with contact lens use may lead to invitation of microbial flora. The accumulation of these bacteria may act as a precursor to biofilm formation, thus colonizing the lens accessories as well. The bacteria isolated in this study were similar to the ones causing microbial keratitis thus, predisposing the otherwise asymptomatic subjects to permanent visual damage.

  6. CMU DeepLens: deep learning for automatic image-based galaxy-galaxy strong lens finding

    Science.gov (United States)

    Lanusse, François; Ma, Quanbin; Li, Nan; Collett, Thomas E.; Li, Chun-Liang; Ravanbakhsh, Siamak; Mandelbaum, Rachel; Póczos, Barnabás

    2018-01-01

    Galaxy-scale strong gravitational lensing can not only provide a valuable probe of the dark matter distribution of massive galaxies, but also provide valuable cosmological constraints, either by studying the population of strong lenses or by measuring time delays in lensed quasars. Due to the rarity of galaxy-scale strongly lensed systems, fast and reliable automated lens finding methods will be essential in the era of large surveys such as Large Synoptic Survey Telescope, Euclid and Wide-Field Infrared Survey Telescope. To tackle this challenge, we introduce CMU DeepLens, a new fully automated galaxy-galaxy lens finding method based on deep learning. This supervised machine learning approach does not require any tuning after the training step which only requires realistic image simulations of strongly lensed systems. We train and validate our model on a set of 20 000 LSST-like mock observations including a range of lensed systems of various sizes and signal-to-noise ratios (S/N). We find on our simulated data set that for a rejection rate of non-lenses of 99 per cent, a completeness of 90 per cent can be achieved for lenses with Einstein radii larger than 1.4 arcsec and S/N larger than 20 on individual g-band LSST exposures. Finally, we emphasize the importance of realistically complex simulations for training such machine learning methods by demonstrating that the performance of models of significantly different complexities cannot be distinguished on simpler simulations. We make our code publicly available at https://github.com/McWilliamsCenter/CMUDeepLens.

  7. Phacoemulsification using iris hooks and scleral fixation of the intraocular lens in patients with secondary glaucoma associated with lens subluxation.

    Science.gov (United States)

    Ma, K T; Lee, H K; Seong, G J; Kim, C Y

    2008-09-01

    We described the techniques and results of phacoemulsification using iris hook and scleral fixation of intraocular lens (IOL) in patients with secondary glaucoma associated with lens subluxation. Eight eyes of seven patients with secondary glaucoma associated with lens dislocation, who had undergone the surgery, were retrospectively reviewed. At a mean of 23.5 months+/-13.6 (SD) after the surgery, the mean best-corrected visual acuity improved from 0.24+/-0.21 to 0.83+/-0.3, and mean intraocular pressure (IOP) was changed from 38.4+/-11.4 to 15.5+/-1.8 mmHg at the final examination. There were no vitreoretinal complications except cystoid macular oedema in one eye. The technique appears to be safe and effective in terms of visual rehabilitation and controlling IOP in patients with secondary glaucoma associated with lens subluxation.

  8. ECTOPIC LENS EXTRACTION IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Vladimir Pfeifer

    2002-12-01

    Full Text Available Background. Ectopia lentis continues to be a therapeutic challenge for ophthalmologists. It can occur as an isolated condition, after ocular trauma, in association with other ocular disorders, as part of a systemic mesodermal disease or a complication of general metabolic disorders. Minimal subluxation of the lens may cause no visual symptoms, but in more advanced cases serious optical disturbances arise. The most important is amblyopia. Surgical treatment options include iris manipulation, lens discission, aspiration, intracapsular or extracapsular extraction, and pars plana lensectomy. The choice of surgical technique remains controversial, in part because of the historically poor visual results and high rate of perioperative complications, including vitreous loss and retinal detachment.Methods. We describe a surgical technique based on the use of the Cionni endocapsular tension ring, dry irrigation aspiration of lens material, centration of the capsular bag and foldable intraocular lens implantation into the bag. With mentioned surgical technique 8 patients were operated; 4 boys and 4 girls, together 11 eyes.Results. The final BCVA after follow up period improved in 9 eyes and it remained the same as before operation in one eye. Statistical comparison of preoperative and postoperative visual acuities showed significant improvement. On the other hand there was no correlation between preoperative and postoperative visual acuity.Conclusions. This surgical procedure is an alternative approach in solving this challenging cases of ectopia lentis with good postoperative visual rehabilitation.

  9. Review on prevention of bacterial adhesion on contact lens using plasma treatment

    Science.gov (United States)

    Ramli, N. A. H.; Zaaba, S. K.; Mustaffa, M. T.; Zakaria, A.; Shahriman A., B.

    2017-03-01

    Many researches had been conducted to enhance the properties of contact lens. Most of the research conducted discussed on the factors that affect the adhesion process to contact lenses, rate of contact lens contamination, and type of microbe that adhere on the contact lens surface and contact lens casing. Studies on the proposed strategies or technology that can be used to slower down the formation of bacteria on contact lens are being explored. New technologies or strategies to prevent or slow down the adhesion of bacteria on contact lens have become a priority in this area. This review paper covers two main aspects, namely factor that affect the bacteria adhesion on contact lens and also the introduction of plasma treatment as a potential method for contact lens treatment.

  10. Effect of infrared radiation on the lens

    Directory of Open Access Journals (Sweden)

    Aly Eman

    2011-01-01

    Full Text Available Background: Infrared (IR radiation is becoming more popular in industrial manufacturing processes and in many instruments used for diagnostic and therapeutic application to the human eye. Aim : The present study was designed to investigate the effect of IR radiation on rabbit′s crystalline lens and lens membrane. Materials and Methods: Fifteen New Zealand rabbits were used in the present work. The rabbits were classified into three groups; one of them served as control. The other two groups were exposed to IR radiation for 5 or 10 minutes. Animals from these two irradiated groups were subdivided into two subgroups; one of them was decapitated directly after IR exposure, while the other subgroup was decapitated 1 hour post exposure. IR was delivered from a General Electric Lamp model 250R 50/10, placed 20 cm from the rabbit and aimed at each eye. The activity of Na + -K + ATPase was measured in the lens membrane. Soluble lens proteins were extracted and the following measurements were carried out: estimation of total soluble protein, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE and Fourier transform infrared (FTIR spectroscopy. For comparison between multiple groups, analysis of variance was used with significance level set at P < 0.001. Results: The results indicated a change in the molecular weight of different lens crystalline accompanied with changes in protein backbone structure. These changes increased for the groups exposed to IR for 10 minutes. Moreover, the activity of Na + -K + ATPase significantly decreased for all groups. Conclusions: The protein of eye lens is very sensitive to IR radiation which is hazardous and may lead to cataract.

  11. Tomographic method for measurement of the gradient refractive index of the crystalline lens. I. The spherical fish lens.

    Science.gov (United States)

    Acosta, Eva; Vazquez, Daniel; Garner, Leon; Smith, George

    2005-03-01

    We present an iterative tomographic algorithm to reconstruct refractive-index profiles for meridional planes of the lens of the spherical fish eye from measurements of deflection angles of refracted rays. Numerical simulations show that the algorithm allows accuracy up to the fourth decimal place, provided that the refractive index can be regarded as an analytical function of the radial coordinate and the experimental errors are neglected. An experimental demonstration is given by applying the algorithm to retrieve the refractive-index profile of a spherical fish lens. The method is conceptually simple and does not require matching of the index of the surrounding medium to that of the surface of the lens, and the related iterative algorithm rapidly converges.

  12. Assay Methods for ACS Activity and ACS Phosphorylation by MAP Kinases In Vitro and In Vivo.

    Science.gov (United States)

    Han, Xiaomin; Li, Guojing; Zhang, Shuqun

    2017-01-01

    Ethylene, a gaseous phytohormone, has profound effects on plant growth, development, and adaptation to the environment. Ethylene-regulated processes begin with the induction of ethylene biosynthesis. There are two key steps in ethylene biosynthesis. The first is the biosynthesis of 1-aminocyclopropane-1-carboxylic acid (ACC) from S-Adenosyl-Methionine (SAM), a common precursor in many metabolic pathways, which is catalyzed by ACC synthase (ACS). The second is the oxidative cleavage of ACC to form ethylene under the action of ACC oxidase (ACO). ACC biosynthesis is the committing and generally the rate-limiting step in ethylene biosynthesis. As a result, characterizing the cellular ACS activity and understanding its regulation are important. In this chapter, we detail the methods used to measure, (1) the enzymatic activity of both recombinant and native ACS proteins, and (2) the phosphorylation of ACS protein by mitogen-activated protein kinases (MAPKs) in vivo and in vitro.

  13. ASSESSMENT OF LENS THICKNESS IN ANGLE CLOSURE DISEASE

    Directory of Open Access Journals (Sweden)

    Nishat Sultana Khayoom

    2016-08-01

    Full Text Available BACKGROUND Anterior chamber depth and lens thickness have been considered as important biometric determinants in primary angle-closure glaucoma. Patients with primary narrow angle may be classified as a primary angle closure suspect (PACS, or as having primary angle closure (PAC or primary angle closure glaucoma (PACG. 23.9% of patients with primary angle closure disease are in India, which highlights the importance of understanding the disease, its natural history, and its underlying pathophysiology, so that we may try to establish effective methods of treatment and preventative measures to delay, or even arrest, disease progression, thereby reducing visual morbidity. AIM To determine the lens thickness using A-scan biometry and its significance in various stages of angle closure disease. MATERIALS AND METHODS Patients attending outpatient department at Minto Ophthalmic Hospital between October 2013 to May 2015 were screened for angle closure disease and subsequently evaluated at glaucoma department. In our study, lens thickness showed a direct correlation with shallowing of the anterior chamber by determining the LT/ ACD ratio. A decrease in anterior chamber depth is proportional to the narrowing of the angle which contributes to the progression of the angle closure disease from just apposition to occlusion enhancing the risk for optic nerve damage and visual field loss. Hence, if the lens thickness values are assessed earlier in the disease process, appropriate intervention can be planned. CONCLUSION Determination of lens changes along with anterior chamber depth and axial length morphometrically can aid in early detection of angle closure. The role of lens extraction for PACG is a subject of increased interest. Lens extraction promotes the benefits of anatomical opening of the angle, IOP reduction and improved vision. This potential intervention may be one among the armamentarium of approaches for PACG. Among the current treatment modalities

  14. Which soft lens power is better for piggyback in keratoconus? Part II.

    Science.gov (United States)

    Romero-Jiménez, Miguel; Santodomingo-Rubido, Jacinto; González-Meijóme, Jose-Manuel; Flores-Rodriguez, Patricia; Villa-Collar, Cesar

    2015-02-01

    To evaluate how soft lens power affects rigid gas-permeable (RGP) lens power and visual acuity (VA) in piggyback fittings for keratoconus. Sixteen keratoconus subjects (30 eyes) were included in the study. Piggyback contact lens fittings combining Senofilcon-A soft lenses of -6.00, -3.00, +3.00 and +6.00 D with Rose K2 RGP contact lenses were performed. Corneal topography was taken on the naked eye and over each soft contact lens before fitting RGP lenses. Mean central keratometry, over-refraction, RGP back optic zone radius (BOZR) and estimated final power as well as VA were recorded and analyzed. In comparison to the naked eye, the mean central keratometry flattened with both negative lens powers (psoft lens power (p=1.0); and steepened with the +6.00 soft lens power (p=0.02). Rigid gas-permeable over-refraction did not change significantly between different soft lens powers (all p>0.05). RGP's BOZR decreased significantly with both positive in comparison with both negative soft lens powers (all ppowers separately (both p>0.05). Estimated RGP's final power increased significantly with positive in comparison with negative lens powers (all ppowers separately (both p>0.05). Visual acuity did not change significantly between the different soft lens powers assessed (all p>0.05). The use of negative-powered soft lenses in piggyback fitting reduces RGP lens power without impacting VA in keratoconus subjects. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  15. Microbial contamination of soft contact lenses & accessories in asymptomatic contact lens users

    Directory of Open Access Journals (Sweden)

    Deeksha V Thakur

    2014-01-01

    Full Text Available Background & objectives: With increasing use of soft contact lenses the incidence of contact lens induced infections is also increasing. This study was aimed to assess the knowledge of new and existing contact lens users about the risk of microbial contamination associated with improper use and maintenance of contact lenses, type of microbial flora involved and their potential to cause ophthalmic infections. Methods: Four samples each from 50 participants (n=200 were collected from the lenses, lens care solutions, lens care solution bottles and lens cases along with a questionnaire regarding their lens use. The samples were inoculated onto sheep blood agar, Mac Conkey′s agar and Sabouraud′s dextrose agar. Organisms were identified using standard laboratory protocols. Results: Overall rate of microbial contamination among the total samples was 52 per cent. The most and the least contaminated samples were found to be lens cases (62% and lens care solution (42%, respectively. The most frequently isolated contaminant was Staphylococcus aureus (21% followed by Pseudomonas species (19.5%. Majority (64% of the participants showed medium grade of compliance to lens cleaning practices. Rate of contamination was 100 and 93.75 per cent respectively in those participants who showed low and medium compliance to lens care practices as compared to those who had high level of compliance (43.75% ( p0 <0.05. Interpretation & conclusions: Lens care practices amongst the participants were not optimum which resulted into high level contamination. Hence, creating awareness among the users about the lens care practices and regular cleaning and replacements of lens cases are required.

  16. Effect of chronic smoking on lens nucleus as assessed by Pentacam HR lens densitometry in young adults.

    Science.gov (United States)

    Pekel, Gökhan; Cetin, Ebru Nevin; Acer, Semra; Yagci, Ramazan; Altintas, Seher; Ongun, Gülin Tugba

    2014-06-01

    To evaluate the effects of chronic tobacco smoking on lens nucleus by Pentacam HR lens densitometry (LD) in young adults. Prospective cross-sectional case series. Thirty subjects (23 M, 7 F) who were chronic cigarette smokers (≥10 cigarettes/day for at least 2 years) (group 1) and another 30 subjects (23 M, 7 F) who did not smoke (group 2), were included in this study. The patients were matched for age and sex between the groups. The exclusion criteria were any history of ocular surgery, any systemic disorders and any ocular diseases except for mild refractive disorders. Lens densitometry measurements were done with the Pentacam HR (Oculus, Wetzlar, Germany). The Schirmer test and pachymetry measurements were also performed. Mean age of the patients for both groups was 28.90 ± 8.20 years (range: 18-40 years). Mean lens densitometry (LD) measurements of Group 1 (chronic cigarette smoking group) were higher than those of Group 2 (control group) in all LD techniques; however only mean "peak" LD measurements showed a statistically significant difference between these two groups (Group 1: 8.67 ± 0.61, Group 2: 8.44 ± 0.70, p = 0.04). The mean Schirmer test value was 12.43 ± 5.60 mm in Group 1 and 13.00 ± 4.26 mm in Group 2 (p = 0.55). The mean central corneal thickness (CCT) value was 564.23 ± 34.61 µm in Group 1 and 550.47 ± 32.94 µm in Group 2 (p = 0.03). The Pentacam HR LD seems to be an important option for the evaluation of lens nucleus in young adults, because it gives objective and quantitative data. Although chronic smoking increases lens nucleus density in young adults, the effect is not statistically significant when compared with the control group.

  17. A planar parabolic refractive nickel lens for high-energy X-rays

    International Nuclear Information System (INIS)

    Andrejczuk, Andrzej; Nagamine, Masaru; Sakurai, Yoshiharu; Itou, Masayoshi

    2013-01-01

    A compound refractive nickel lens focusing 174 keV X-rays to 5 µm with a gain of 4 is presented. A compound refractive lens made of nickel and designed for focusing high-energy synchrotron X-rays is presented. The lens consists of 600 parabolic grooves and focuses X-rays in one plane only (planar lens). The lenses made and investigated by us earlier exhibited low transmission and irregularities in the focused beam profile. Since then, improvements in lens manufacturing technology have been made. The present lens gives an almost Gaussian profile and produces four times higher intensity at its maximum compared with the intensity of primary X-ray beams of 174 keV

  18. Design of a hyperbolic microwave metallic lens

    International Nuclear Information System (INIS)

    Uckan, T.

    1979-12-01

    Due to problems caused by multiple reflections in the cavity walls of the EBT fusion research device, the use of a horn becomes important for the directivity of waves in the millimetric range. An ordinary dielectric lens cannot be used because of plasma-wall interactions. Microwave metallic lenses, designed to focus the energy into a plane wave, can improve the directivity considerably. By implementing a 70-GHz standard-gain horn with a delay-type hyperbolic lens, which consists of a solid metallic disk with a number of equal size small holes has indicated a gain of 15 dB over the no lens case

  19. 3D printed helical antenna with lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2016-12-19

    The gain of an antenna can be enhanced through the integration of a lens, however this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, with a unique combination of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a Fresnel lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a Fresnel lens enhances the gain of a 2-turn helix by around 4.6 dB giving a peak gain of about 12.9 dBi at 8.8 GHz.

  20. Magnetic lens apparatus for a low-voltage high-resolution electron microscope

    Science.gov (United States)

    Crewe, Albert V.

    1996-01-01

    A lens apparatus in which a beam of charged particles of low accelerating voltage is brought to a focus by a magnetic field, the lens being situated behind the target position. The lens comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. The lens apparatus comprises the sole focusing lens for high-resolution imaging in a low-voltage scanning electron microscope.

  1. Lens system for SIMS analysis

    International Nuclear Information System (INIS)

    Martinez, G.; Sancho, M.; Garcia-Galan, J.C.

    1987-01-01

    A powerful version of the charge-density method is applied to the study of a combined objective and emission lens, suitable for highly localized analysis of a flat sample surface. This lens can extract secondary ions of equal or opposite polarity to that of the primary particles. A computer simulation of the ion trajectories for both modes is made. The behaviour for different values of the geometric parameters and polarizations is analyzed and useful data for design such as primary beam demagnification and secondary image position are given. (author) 4 refs

  2. Variable-focus liquid lens for portable applications

    NARCIS (Netherlands)

    Kuiper, S.; Hendriks, B.H.W.; Huijbregts, L.J.; Hirschberg, A.; Renders, C.A.; As, van M.A.J.; Mouroulis, P.Z.; Smith, W.J.; Johnson, R.B.

    2004-01-01

    The meniscus between two immiscible liquids can be used as an optical lens. A change in curvature of this meniscus by electrowetting leads to a change in focal distance. We demonstrate that two liquids in a tube form a self-centered tunable lens of high optical quality. Several properties were

  3. 21 CFR 886.4300 - Intraocular lens guide.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4300 Intraocular lens guide. (a) Identification. An intraocular lens guide is a device intended to be inserted into the eye during surgery to direct... lenses, the device is exempt from the premarket notification procedures in subpart E of part 807 of this...

  4. Treatment of contact lens related dry eye with antibacterial honey.

    Science.gov (United States)

    Wong, Daniel; Albietz, Julie M; Tran, Huan; Du Toit, Cimonette; Li, Anita Hui; Yun, Tina; Han, Jee; Schmid, Katrina L

    2017-12-01

    Contact lens induced dry eye affects approximately 50% of contact lens wearers. The aim was to assess the effects of Manuka (Leptospermum sp.) honey eye drops (Optimel, Melcare, Australia) on dry eye in contact lens wearers. The safety of the honey eye drops in contact lens wear and contact lens wearers' compliance were also evaluated. Prospective, randomised, cross over study, examiner masked, pilot treatment trial. Twenty-four participants aged 20 to 55 years with contact lens related dry eye were recruited and randomised to two treatment groups; 20 completed the study. One group used Optimel eye drops twice a day for two weeks followed by conventional lubricant (Systane Ultra, Alcon) therapy for two weeks; the other group completed the treatments in the reverse order. Before and after each treatment dry eye symptomology, ocular surface inflammation, and tear quantity and quality were assessed. Participants completed a daily log detailing their usage of treatments and any issues. Dry eye symptoms improved significantly after Optimel treatment. Patients with more severe symptoms at baseline showed a greater improvement in symptoms. No significant differences were observed in the objective signs of dry eye; presumably because of the short treatment duration. Seventy-five% of contact lens wearers reported good adherence to Optimel treatment and 95% reported no issues using this product. Optimel Eye Drops reduce the symptoms of dry eye in contact lens wearers and are safe to use. A longer treatment period to assess the effect on clinical signs of dry eye is required. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  5. Gram negative bacteria and contact lens induced acute red eye

    Directory of Open Access Journals (Sweden)

    Sankaridurg Padmaja

    1996-01-01

    Full Text Available Two patients using hydrogel contact lenses on a daily wear schedule slept overnight with the lenses and woke up with a Contact Lens Induced Acute Red Eye (CLARE. The contact lenses recovered aseptically at the time of the event grew significant colonies of Pseudomonas aeruginosa and Aeromonas hydrophila in patient A and Pseudomonas aeruginosa and Serratia liquefaciens from patient B. Similar organisams from the contact lenses were recovered from the lens case and lens care solutions of patient B. In both the patients the condition resolved on discontinuation of lens wear. Patient compliance as a requirement for successful contact lens wear is highlighted with the illustration of these cases.

  6. An all-silicone zoom lens in an optical imaging system

    Science.gov (United States)

    Zhao, Cun-Hua

    2013-09-01

    An all-silicone zoom lens is fabricated. A tunable metal ringer is fettered around the side edge of the lens. A nylon rope linking a motor is tied, encircling the notch in the metal ringer. While the motor is operating, the rope can shrink or release to change the focal length of the lens. A calculation method is developed to obtain the focal length and the zoom ratio. The testing is carried out in succession. The testing values are compared with the calculated ones, and they tally with each other well. Finally, the imaging performance of the all-silicone lens is demonstrated. The all-silicone lens has potential uses in cellphone cameras, notebook cameras, micro monitor lenses, etc.

  7. Minimizing and measuring lens dose when giving cranial irradiation

    International Nuclear Information System (INIS)

    Woo, S.Y.; Donaldson, S.S.; Heck, R.J.; Nielson, K.L.; Shostak, C.

    1989-01-01

    Three different techniques of administering cranial irradiation were used to determine the dose to the lens as measured in the Rando phantom. The techniques employed were as follows: (1) the central axis of the radiation beam was placed at the thickest portion of the cranium; (2) the central axis of the radiation beam was placed at the lateral orbital rim (bon canthus); (3) the central axis of the radiation beam was placed at the thickest portion of the cranium but with the beam angled 5deg posteriorly away from the eye. Thermal luminescent dosimeters (TLD) were placed in a phantom, at a point determined from a life-sized anatomical section of the plane through the midsection of the eye, to be at the location of the posterior capsule of the lens. In addition, TLDs were placed on the outer surface of the phantom head, directly lateral to the location determined to be where the lens would lie. With equally weighted lateral opposed beams, delivering a midplane dose of 200cGy, the TLDs at the point of the lens measured 21, 9.9 and 10.6% of the midplane doses from the three techniques respectively. TLDs placed directly lateral to the lens on the surface of the phantom head gave an approximation of the lens dose, particularly when techniques 2 and 3 were used. Isodose curve generated by a General Electric treatment planning computer gave lens doses similar to those of the phantom data for each of the three different radiotherapy techniques. Cranial irradiation should be carried out by either technique 2 or technique 3 to minimize radiation dose to the lens. (author). 11 refs.; 2 figs.; 3 tabs

  8. Qualification of a Null Lens Using Image-Based Phase Retrieval

    Science.gov (United States)

    Bolcar, Matthew R.; Aronstein, David L.; Hill, Peter C.; Smith, J. Scott; Zielinski, Thomas P.

    2012-01-01

    In measuring the figure error of an aspheric optic using a null lens, the wavefront contribution from the null lens must be independently and accurately characterized in order to isolate the optical performance of the aspheric optic alone. Various techniques can be used to characterize such a null lens, including interferometry, profilometry and image-based methods. Only image-based methods, such as phase retrieval, can measure the null-lens wavefront in situ - in single-pass, and at the same conjugates and in the same alignment state in which the null lens will ultimately be used - with no additional optical components. Due to the intended purpose of a Dull lens (e.g., to null a large aspheric wavefront with a near-equal-but-opposite spherical wavefront), characterizing a null-lens wavefront presents several challenges to image-based phase retrieval: Large wavefront slopes and high-dynamic-range data decrease the capture range of phase-retrieval algorithms, increase the requirements on the fidelity of the forward model of the optical system, and make it difficult to extract diagnostic information (e.g., the system F/#) from the image data. In this paper, we present a study of these effects on phase-retrieval algorithms in the context of a null lens used in component development for the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission. Approaches for mitigation are also discussed.

  9. Plasmonic leak-free focusing lens under radially polarized illumination

    International Nuclear Information System (INIS)

    Li, Xiaowei; Tan, Qiaofeng; Bai, Benfeng; Jin, Guofan

    2010-01-01

    A plasmonic leak-free focusing lens with two asymmetric concentric ring slits under radially polarized illumination is proposed. Each ring slit in the plasmonic lens is designed to generate surface plasmon polaritons (SPPs) with a relative initial phase controlled by the ring slit parameters. Through mutual interference of the SPPs with different phases excited by the two concentric ring slits at the output metal–dielectric interface, the field intensity towards the center of the focusing lens can be enhanced while that leaking to the counter-focus direction is effectively suppressed. The optimal parameters of the plasmonic leak-free lens are theoretically obtained by satisfying the above condition and its focusing performance is demonstrated by numerical simulation. Furthermore, a plasmonic leak-free lens with multiple double-slit groups is proposed and discussed, which exhibits a higher energy density at the focusing spot of the output interface

  10. Development of a 3D finite element model of lens microcirculation

    Directory of Open Access Journals (Sweden)

    Vaghefi Ehsan

    2012-09-01

    Full Text Available Abstract Background It has been proposed that in the absence of a blood supply, the ocular lens operates an internal microcirculation system. This system delivers nutrients, removes waste products and maintains ionic homeostasis in the lens. The microcirculation is generated by spatial differences in membrane transport properties; and previously has been modelled by an equivalent electrical circuit and solved analytically. While effective, this approach did not fully account for all the anatomical and functional complexities of the lens. To encapsulate these complexities we have created a 3D finite element computer model of the lens. Methods Initially, we created an anatomically-correct representative mesh of the lens. We then implemented the Stokes and advective Nernst-Plank equations, in order to model the water and ion fluxes respectively. Next we complemented the model with experimentally-measured surface ionic concentrations as boundary conditions and solved it. Results Our model calculated the standing ionic concentrations and electrical potential gradients in the lens. Furthermore, it generated vector maps of intra- and extracellular space ion and water fluxes that are proposed to circulate throughout the lens. These fields have only been measured on the surface of the lens and our calculations are the first 3D representation of their direction and magnitude in the lens. Conclusion Values for steady state standing fields for concentration and electrical potential plus ionic and fluid fluxes calculated by our model exhibited broad agreement with observed experimental values. Our model of lens function represents a platform to integrate new experimental data as they emerge and assist us to understand how the integrated structure and function of the lens contributes to the maintenance of its transparency.

  11. Two-laser thermal-lens determination of phosphorus in silicon

    International Nuclear Information System (INIS)

    Grishko, V.I.; Gol'dshtein, M.M.; Grishko, V.P.; Yudelevich, I.G.

    1986-01-01

    Laser thermal-lens spectrophotometry is a high-sensitivity method of measuring absorptivity, where the signal is the relative intensity change at the beam center after passage through the medium, which absorbs at the laser wavelength. The two-lens method is discussed here which employs a high-power laser to induce the lens, while the absorptivity is measured from the intensity change in the beam from a continous wave low-power test laser at a wavelength different from that for the inducing one. This paper uses two-laser thermal-lens techniques to determine phosphorus in silicon. Phosphorus is determined as the ionic association of molybdophosphoric acid with auramine

  12. [Phacoemulsification of subluxated lens with capsular tension ring implantation].

    Science.gov (United States)

    Dorecka, Mariola; Rokicki, Wojciech; Nita, Malgorzata; Krysik, Katarzyna; Nita, Ewa; Sikorska, Aleksandra; Romaniuk, Wanda

    2007-01-01

    To evaluate long term results of phacoemulsification with PC IOL and capsular tension ring (CTR) implantation in lens subluxation. The study comprised of 134 patients--146 eyes with subluxated lens. In all cases phacoemulsification with PC IOL and CTR implantation was performed. No intaroperative complications has occured. Postoperative complications included: inflammation in the anterior chamber in 3 eyes (2.1%), retinal detachment in 2 eyes (1.4%). In all cases there was no PC IOL decentration. (1) CTR facilitates phacoemulsification with PC IOL implantation in lens subluxation. (2) Phacoemulsification of subluxated lens with PC IOL and CTR implantation seems to be safe and effective procedure.

  13. The Mars Hand Lens Imager (MAHLI) aboard the Mars rover, Curiosity

    Science.gov (United States)

    Edgett, K. S.; Ravine, M. A.; Caplinger, M. A.; Ghaemi, F. T.; Schaffner, J. A.; Malin, M. C.; Baker, J. M.; Dibiase, D. R.; Laramee, J.; Maki, J. N.; Willson, R. G.; Bell, J. F., III; Cameron, J. F.; Dietrich, W. E.; Edwards, L. J.; Hallet, B.; Herkenhoff, K. E.; Heydari, E.; Kah, L. C.; Lemmon, M. T.; Minitti, M. E.; Olson, T. S.; Parker, T. J.; Rowland, S. K.; Schieber, J.; Sullivan, R. J.; Sumner, D. Y.; Thomas, P. C.; Yingst, R. A.

    2009-08-01

    The Mars Science Laboratory (MSL) rover, Curiosity, is expected to land on Mars in 2012. The Mars Hand Lens Imager (MAHLI) will be used to document martian rocks and regolith with a 2-megapixel RGB color CCD camera with a focusable macro lens mounted on an instrument-bearing turret on the end of Curiosity's robotic arm. The flight MAHLI can focus on targets at working distances of 20.4 mm to infinity. At 20.4 mm, images have a pixel scale of 13.9 μm/pixel. The pixel scale at 66 mm working distance is about the same (31 μm/pixel) as that of the Mars Exploration Rover (MER) Microscopic Imager (MI). MAHLI camera head placement is dependent on the capabilities of the MSL robotic arm, the design for which presently has a placement uncertainty of ~20 mm in 3 dimensions; hence, acquisition of images at the minimum working distance may be challenging. The MAHLI consists of 3 parts: a camera head, a Digital Electronics Assembly (DEA), and a calibration target. The camera head and DEA are connected by a JPL-provided cable which transmits data, commands, and power. JPL is also providing a contact sensor. The camera head will be mounted on the rover's robotic arm turret, the DEA will be inside the rover body, and the calibration target will be mounted on the robotic arm azimuth motor housing. Camera Head. MAHLI uses a Kodak KAI-2020CM interline transfer CCD (1600 x 1200 active 7.4 μm square pixels with RGB filtered microlenses arranged in a Bayer pattern). The optics consist of a group of 6 fixed lens elements, a movable group of 3 elements, and a fixed sapphire window front element. Undesired near-infrared radiation is blocked using a coating deposited on the inside surface of the sapphire window. The lens is protected by a dust cover with a Lexan window through which imaging can be ac-complished if necessary, and targets can be illuminated by sunlight or two banks of two white light LEDs. Two 365 nm UV LEDs are included to search for fluores-cent materials at night. DEA

  14. Improved integrating-sphere throughput with a lens and nonimaging concentrator.

    Science.gov (United States)

    Chenault, D B; Snail, K A; Hanssen, L M

    1995-12-01

    A reflectometer design utilizing an integrating sphere with a lens and nonimaging concentrator is described. Compared with previous designs where a collimator was used to restrict the detector field of view, the concentrator-lens combination significantly increases the throughput of the reflectometer. A procedure for designing lens-concentrators is given along with the results of parametric studies. The measured angular response of a lens-concentrator system is compared with ray-trace predictions and with the response of an ideal system.

  15. RNA interference suppression of mucin 5AC (MUC5AC reduces the adhesive and invasive capacity of human pancreatic cancer cells

    Directory of Open Access Journals (Sweden)

    Yamada Nobuya

    2010-05-01

    Full Text Available Abstract Background MUC5AC is a secretory mucin normally expressed in the surface muconous cells of stomach and bronchial tract. It has been known that MUC5AC de novo expression occurred in the invasive ductal carcinoma and pancreatic intraepithelial neoplasm with no detectable expression in normal pancreas, however, its function remains uncertain. Here, we report the impact of MUC5AC on the adhesive and invasive ability of pancreatic cancer cells. Methods We used two MUC5AC expressing cell lines derived from human pancreatic cancer, SW1990 and BxPC3. Small-interfering (si RNA directed against MUC5AC were used to assess the effects of MUC5AC on invasion and adhesion of pancreas cancer cells in vitro and in vivo. We compared parental cells (SW1990 and BxPC3 with MUC5AC suppressed cells by si RNA (si-SW1990 and si-BxPC3. Results MUC5AC was found to express in more than 80% of pancreatic ductal carcinoma specimens. Next we observed that both of si-SW1990 and si-BxPC3 showed significantly lower adhesion and invasion to extracellular matrix components compared with parental cell lines. Expression of genes associated with adhesion and invasion including several integerins, matrix metalloproteinase (MMP -3 and vascular endothelial growth factor (VEGF were down-regulated in both MUC5AC suppressed cells. Furthermore, production of VEGF and phosphorylation of VEGFR-1 were significantly reduced by MUC5AC down regulation. Both of si-SW1990 and si-BxPC3 attenuated activation of Erk1/2. In vivo, si-SW1990 did not establish subcutaneous tumor in nude mice. Conclusions Knockdown of MUC5AC reduced the ability of pancreatic cancer cells to adhesion and invasion, suggesting that MUC5AC might contribute to the invasive motility of pancreatic cancer cells by enhancing the expression of integrins, MMP-3, VEGF and activating Erk pathway.

  16. Primary intraocular lens implantation for penetrating lens trauma in Africa.

    Science.gov (United States)

    Bowman, R J; Yorston, D; Wood, M; Gilbert, C; Foster, A

    1998-09-01

    This study aimed to audit the surgical strategy of primary posterior chamber intraocular lens implantation for cases of recent penetrating trauma involving the lens in an African population. Retrospective, noncomparative case series. Seventy-two cases are reported, including all patients who underwent primary intraocular lens implantation for traumatic cataract extraction performed within 1 month of injury between 1988 and 1996. Demographic characteristics and follow-up attendance rates are analyzed. Surgical technique and the occurrence of intraoperative and postoperative complications are reported. Visual outcomes are reported with detailed analysis for cases of poor visual outcome. Mean age was 14.3 years (standard deviation = 11.1), 57 (79%) were male and 15 (21%) were female (chi-square = 23.66, P capsule had been breached by the trauma in 27 (38%) cases, and 15 of these required anterior vitrectomy. Capsular fixation of the implant was achieved in 49% of patients, the remainder having sulcus fixation. Intraoperative rupture of the posterior capsule occurred in four cases. The only common postoperative complication was acute fibrinous anterior uveitis, which occurred in 29 (40%) patients, and 32% of patients followed up for at least 6 months required secondary posterior capsulotomy. This was more common in younger patients (chi-square = 4.2, P < 0.05). Corrected postoperative visual acuities were available for 51 patients, of which 71% achieved 20/60 or better visual acuity. Patients 6 years of age or younger were less likely to achieve 20/60 (chi-square = 6.61, P = 0.01). This surgical strategy has proved successful, producing good visual results and causing no sight-threatening complications. Primary posterior capsulotomy may be appropriate for younger patients.

  17. Gamma-irradiation produces active chlorine species (ACS) in physiological solutions: Secoisolariciresinol diglucoside (SDG) scavenges ACS - A novel mechanism of DNA radioprotection.

    Science.gov (United States)

    Mishra, Om P; Popov, Anatoliy V; Pietrofesa, Ralph A; Christofidou-Solomidou, Melpo

    2016-09-01

    Secoisolariciresinol diglucoside (SDG), the main lignan in whole grain flaxseed, is a potent antioxidant and free radical scavenger with known radioprotective properties. However, the exact mechanism of SDG radioprotection is not well understood. The current study identified a novel mechanism of DNA radioprotection by SDG in physiological solutions by scavenging active chlorine species (ACS) and reducing chlorinated nucleobases. The ACS scavenging activity of SDG was determined using two highly specific fluoroprobes: hypochlorite-specific 3'-(p-aminophenyl) fluorescein (APF) and hydroxyl radical-sensitive 3'-(p-hydroxyphenyl) fluorescein (HPF). Dopamine, an SDG structural analog, was used for proton (1)H NMR studies to trap primary ACS radicals. Taurine N-chlorination was determined to demonstrate radiation-induced generation of hypochlorite, a secondary ACS. DNA protection was assessed by determining the extent of DNA fragmentation and plasmid DNA relaxation following exposure to ClO(-) and radiation. Purine base chlorination by ClO(-) and γ-radiation was determined by using 2-aminopurine (2-AP), a fluorescent analog of 6-aminopurine. Chloride anions (Cl(-)) consumed >90% of hydroxyl radicals in physiological solutions produced by γ-radiation resulting in ACS formation, which was detected by (1)H NMR. Importantly, SDG scavenged hypochlorite- and γ-radiation-induced ACS. In addition, SDG blunted ACS-induced fragmentation of calf thymus DNA and plasmid DNA relaxation. SDG treatment before or after ACS exposure decreased the ClO(-) or γ-radiation-induced chlorination of 2-AP. Exposure to γ-radiation resulted in increased taurine chlorination, indicative of ClO(-) generation. NMR studies revealed formation of primary ACS radicals (chlorine atoms (Cl) and dichloro radical anions (Cl2¯)), which were trapped by SDG and its structural analog dopamine. We demonstrate that γ-radiation induces the generation of ACS in physiological solutions. SDG treatment scavenged

  18. Hopping models and ac universality

    DEFF Research Database (Denmark)

    Dyre, Jeppe; Schrøder, Thomas

    2002-01-01

    Some general relations for hopping models are established. We proceed to discuss the universality of the ac conductivity which arises in the extreme disorder limit of the random barrier model. It is shown that the relevant dimension entering into the diffusion cluster approximation (DCA) is the h......Some general relations for hopping models are established. We proceed to discuss the universality of the ac conductivity which arises in the extreme disorder limit of the random barrier model. It is shown that the relevant dimension entering into the diffusion cluster approximation (DCA......) is the harmonic (fracton) dimension of the diffusion cluster. The temperature scaling of the dimensionless frequency entering into the DCA is discussed. Finally, some open problems regarding ac universality are listed....

  19. Electronic states in a quantum lens

    International Nuclear Information System (INIS)

    Rodriguez, Arezky H.; Trallero-Giner, C.; Ulloa, S. E.; Marin-Antuna, J.

    2001-01-01

    We present a model to find analytically the electronic states in self-assembled quantum dots with a truncated spherical cap (''lens'') geometry. A conformal analytical image is designed to map the quantum dot boundary into a dot with semispherical shape. The Hamiltonian for a carrier confined in the quantum lens is correspondingly mapped into an equivalent operator and its eigenvalues and eigenfunctions for the corresponding Dirichlet problem are analyzed. A modified Rayleigh-Schro''dinger perturbation theory is presented to obtain analytical expressions for the energy levels and wave functions as a function of the spherical cap height b and radius a of the circular cross section. Calculations for a hard wall confinement potential are presented, and the effect of decreasing symmetry on the energy values and eigenfunctions of the lens-shape quantum dot is studied. As the degeneracies of a semicircular geometry are broken for b≠a, our perturbation approach allows tracking of the split states. Energy states and electronic wave functions with m=0 present the most pronounced influence on the reduction of the lens height. The method and expressions presented here can be straightforwardly extended to deal with more general Hamiltonians, including strains and valence-band coupling effects in Group III--V and Group II--VI self-assembled quantum dots

  20. Forensic Analysis of a Contact Lens in a Murder Case.

    Science.gov (United States)

    Zwerling, Charles S

    2016-03-01

    Contact lenses have had rare relevance in trials and/or investigations. After 5 years of burial, orbital remnants were retrieved from an exhumed body and subsequently identified as a key piece of material evidence in a murder trial. The exhumed case materials were evaluated under laboratory conditions and were determined to be contact lens remnants. Contact lens fracture and burial simulation studies were performed to provide additional corroboration of the physical findings of the exhumed contact lens remnants. This material evidence was instrumental in providing factual proof refuting the defendant's testimony in the murder trial. A brief history of contact lens composition and use is provided for understanding the methods and observational results. This forensic case study represents the first published documentation of a contact lens from an exhumed body being used in a murder investigation and establishes an operational procedure for future forensic contact lens examinations. © 2016 American Academy of Forensic Sciences.