Read by QxMD icon Read

V beam

R Kieffer, M Bergamaschi, E Bravin, W Farabolini, P Karataev, T Lefevre, S Mazzoni
We report the observation of shadowing between two optical transition radiation (OTR) sources from a 205 MeV electron beam. The total optical intensity is measured as a function of the distance d between the sources, covering the range 0<d<4L_{v}, where L_{v} is the formation length of the particles. Data show that the total optical intensity starts decreasing due to shadowing when d approaches L_{v} until it becomes undetectable for very short distances d/L_{v}→0. A model based solely on interference between the two OTR sources is in good agreement with experimental data...
March 2, 2018: Physical Review Letters
Berc Kalanyan, William A Kimes, Ryan Beams, Stephan J Stranick, Elias Garratt, Irina Kalish, Albert V Davydov, Ravindra K Kanjolia, James E Maslar
High volume manufacturing of devices based on transition metal dichalcogenide (TMD) ultra-thin films will require deposition techniques that are capable of reproducible wafer-scale growth with monolayer control. To date, TMD growth efforts have largely relied upon sublimation and transport of solid precursors with minimal control over vapor phase flux and gas-phase chemistry, which are critical for scaling up laboratory processes to manufacturing settings. To address these issues, we report a new pulsed metalorganic chemical vapor deposition (MOCVD) route for MoS2 film growth in a research-grade single-wafer reactor...
August 8, 2017: Chemistry of Materials: a Publication of the American Chemical Society
X Melody Qu, Vikram M Velker, Eric Leung, Janice S Kwon, Mohamed A Elshaikh, Iwa Kong, Natalie A Logie, Lucas C Mendez, Louis J van der Putten, Elysia K Donovan, Adnan R Munkarah, Ericka M Wiebe, Carlos Parra-Herran, Andrew Warner, Alexander V Louie, David P D'Souza
OBJECTIVE: As the optimal adjuvant management of stage IA serous or clear cell endometrial cancer is controversial, a multi-institutional review was conducted with the objective of evaluating the appropriateness of various strategies including observation. METHODS: Retrospective chart reviews for 414 consecutive patients who underwent hysterectomy for FIGO stage IA endometrial cancer with serous, clear cell or mixed histology between 2004 and 2015 were conducted in 6 North American centers...
March 12, 2018: Gynecologic Oncology
Mark T Corkum, Wei Liu, David A Palma, Glenn S Bauman, Robert E Dinniwell, Andrew Warner, Mark V Mishra, Alexander V Louie
BACKGROUND: Cancer patients frequently search the Internet for treatment options, and hospital websites are seen as reliable sources of knowledge. Guidelines support the use of proton radiotherapy in specific disease sites or on clinical trials. This study aims to evaluate direct-to-consumer advertising content and claims made by proton therapy centre (PTC) websites worldwide. METHODS: Operational PTC websites in English were identified through the Particle Therapy Co-Operative Group website...
March 15, 2018: Radiation Oncology
Sushanta Kumar Pal, P Senthilkumaran
The dependence of fringe contrast on the state of polarization (SOP) can be altered when more than two beams interfere, and it is possible to achieve high contrast fringes. We use a six-pinhole interferometer, in which a judicious choice (but not unique) of SOPs for the interfering beams is made to realize the lattice of C points at intensity nulls. These dark C points occur due to overlapping of singularities. These are not simply a minor variation of bright C points, in which the intensity dims to zero, but are poorly understood, unusual objects in their own right...
March 15, 2018: Optics Letters
J A Marozas, M Hohenberger, M J Rosenberg, D Turnbull, T J B Collins, P B Radha, P W McKenty, J D Zuegel, F J Marshall, S P Regan, T C Sangster, W Seka, E M Campbell, V N Goncharov, M W Bowers, J-M G Di Nicola, G Erbert, B J MacGowan, L J Pelz, S T Yang
Cross-beam energy transfer (CBET) results from two-beam energy exchange via seeded stimulated Brillouin scattering, which detrimentally reduces ablation pressure and implosion velocity in direct-drive inertial confinement fusion. Mitigating CBET is demonstrated for the first time in inertial-confinement implosions at the National Ignition Facility by detuning the laser-source wavelengths (±2.3  Å UV) of the interacting beams. We show that, in polar direct-drive, wavelength detuning increases the equatorial region velocity experimentally by 16% and alters the in-flight shell morphology...
February 23, 2018: Physical Review Letters
Serhat Tozburun, Cedric Blatter, Meena Siddiqui, Eelco F J Meijer, Benjamin J Vakoc
We present a swept-wavelength optical coherence tomography (OCT) system with a 19 MHz laser source and electronic phase-locking of the source, acquisition clock, and beam scanning mirrors. The laser is based on stretched-pulse active mode-locking using an electro-optic modulator. Beam scanning in the fast axis uses a resonant micro-electromechanical systems (MEMS) -based mirror at ~23.8 kHz. Acquisition is performed at 1.78 Gigasamples per second using an external fixed clock. Phase sensitive imaging without need for k-clocking, A-line triggers, or phase-calibration methods is demonstrated...
March 1, 2018: Biomedical Optics Express
Miguel V Drummond, Vanessa C Duarte, André Albuquerque, Rogério N Nogueira, Leontios Stampoulidis, Georg Winzer, Lars Zimmermann, Stephen Clements, Javad Anzalchi
The design and dimensioning of a photonic-aided payload for a multi-beam high-throughput communications satellite is a complex problem in which the antenna, RF and photonic subsystems must be considered as a whole for achieving best performance with lowest mass and power consumption. In this paper, we propose and dimension the receiving stage of a communications satellite comprising a phased array antenna (PAA) feeding a multibeam photonic beamforming system (PBS). The PBS uses a single wavelength and resorts to heterodyne detection such that the retrieved beams are frequency downconverted...
March 5, 2018: Optics Express
M D Rotondaro, B V Zhdanov, M K Shaffer, R J Knize
We performed a measurement of the beam quality of an optimized moderate power cesium Diode Pumped Alkali Laser (DPAL). The DPAL used a stable resonator and operated in continuous wave mode using a static cell filled with metallic cesium and a mixture of methane and helium at 200 and 400 torr respectively. In this work, we characterized the spatial quality of the DPAL output beam. As a result of these experiments we determined the output beam quality was excellent (M2 < 1.2) in the whole range of pump power used (up to 11...
March 5, 2018: Optics Express
Avi Abadi, Gabor Kosa
Automatic manipulation of microscopic particles is very important in biology, especially in new lab-on-chip systems for automatic testing and DNA manipulation. We suggest a particle manipulation system (PMS) based on vibrating piezoelectric beams creating steady streaming flow in a viscous liquid. The flow is nearly unidirectional and it is used to control the position and velocity of the particles in the workspace of the PMS. The particles position in the PMS are controlled by visual feedback. This study presents the manipulation method, the system's model describing its behavior and characterizes experimentally its performance...
March 9, 2018: Biomedical Microdevices
Yu Sun, Qian Wang, Shunjie Gu, Zaoneng He, Qingfeng Wang, Fucheng Zhang
A medium-carbon Cr-Mo-V martensitic steel was thermally processed by quenching (Q) at 890 °C and tempering (T) at increasing temperatures from 650 °C to 720 °C and the effect of tempering temperature, T t , on sulfide stress cracking (SSC) behaviors was estimated mainly via double cantilever beam (DCB) and electrochemical hydrogen permeation (EHP) tests and microstructure characterization. The results indicate that the threshold stress intensity factor for SSC, K ISSC , increased with increasing T t . The overall and local H concentration around the inclusions decreased with increasing T t , due to reductions in the amounts of solute atoms, grain boundaries and dislocations, which effectively prevented SSC initiation...
March 9, 2018: Materials
G G Kozlov, V S Zapasskii, P Yu Shapochkin
The signal registered by a plane photodetector placed behind an optically inhomogeneous object irradiated by two coherent Gaussian beams intersecting inside the object at a small angle to each other is calculated in the single-scattering approximation. In the considered arrangement, only one of the beams hits the detector and serves as the local oscillator for heterodyning the field scattered by the other beam (not hitting the detector). The results of analytical calculation show that the signal detected in this way is contributed only by the region of the inhomogeneous object where the two beams overlap...
March 1, 2018: Applied Optics
Tapan Das, B P V Dileep, Pranab K Dutta
Near-infrared imaging (NIRI) is a sub-surface imaging that makes a trade-off in recovery accuracy with depth of penetration. On the other hand, diffuse optical tomography (DOT) images tissue up to several centimeters. However, DOT reconstruction has a stability issue due to the inverse problem. This paper proposes a generalized continuous-wave technique to image objects of dimensions 4-6 cm comparable to DOT. A nonlinear Rosenbrock's banana function is fitted to the approximate photon path, and the fit parameter thus obtained gives the penetration depth of each channel...
March 10, 2018: Applied Optics
Francesca Urban, Maurizio Passacantando, Filippo Giubileo, Laura Iemmo, Antonio Di Bartolomeo
We report the electrical characterization and field emission properties of MoS 2 bilayers deposited on a SiO 2 / Si substrate. Current-voltage characteristics are measured in the back-gate transistor configuration, with Ti contacts patterned by electron beam lithography. We confirm the n-type character of as-grown MoS 2 and we report normally-on field-effect transistors. Local characterization of field emission is performed inside a scanning electron microscope chamber with piezo-controlled tungsten tips working as the anode and the cathode...
March 8, 2018: Nanomaterials
Y Azamoum, V Tcheremiskine, R Clady, A Ferré, L Charmasson, O Utéza, M Sentis
We present an extended experimental study of the absolute yield of Kα x-ray source (17.48 keV) produced by interaction of an ultrahigh intensity femtosecond laser with solid Mo target for temporal contrast ratios in the range of 1.7 × 107 -3.3 × 109 and on three decades of intensity 1016 -1019   W/cm². We demonstrate that for intensity I ≥ 2 × 1018   W/cm² Kα x-ray emission is independent of the value of contrast ratio. In addition, no saturation of the Kα photon number is measured and a value of ~2 × 1010 photons/sr/s is obtained at 10 Hz and I ~1019   W/cm²...
March 7, 2018: Scientific Reports
Amar U Kishan, Ryan R Cook, Jay P Ciezki, Ashley E Ross, Mark M Pomerantz, Paul L Nguyen, Talha Shaikh, Phuoc T Tran, Kiri A Sandler, Richard G Stock, Gregory S Merrick, D Jeffrey Demanes, Daniel E Spratt, Eyad I Abu-Isa, Trude B Wedde, Wolfgang Lilleby, Daniel J Krauss, Grace K Shaw, Ridwan Alam, Chandana A Reddy, Andrew J Stephenson, Eric A Klein, Daniel Y Song, Jeffrey J Tosoian, John V Hegde, Sun Mi Yoo, Ryan Fiano, Anthony V D'Amico, Nicholas G Nickols, William J Aronson, Ahmad Sadeghi, Stephen Greco, Curtiland Deville, Todd McNutt, Theodore L DeWeese, Robert E Reiter, Johnathan W Said, Michael L Steinberg, Eric M Horwitz, Patrick A Kupelian, Christopher R King
Importance: The optimal treatment for Gleason score 9-10 prostate cancer is unknown. Objective: To compare clinical outcomes of patients with Gleason score 9-10 prostate cancer after definitive treatment. Design, Setting, and Participants: Retrospective cohort study in 12 tertiary centers (11 in the United States, 1 in Norway), with 1809 patients treated between 2000 and 2013. Exposures: Radical prostatectomy (RP), external beam radiotherapy (EBRT) with androgen deprivation therapy, or EBRT plus brachytherapy boost (EBRT+BT) with androgen deprivation therapy...
March 6, 2018: JAMA: the Journal of the American Medical Association
Egor Leshchenko, Paul Kuyanov, Ray R LaPierre, Vladimir G Dubrovskii
Patterned arrays of self-assisted GaP nanowires were grown on a Si substrate by gas source molecular beam epitaxy using various V/III flux ratios from 1 to 6, and various pitches from 360 to 1000 nm. As the V/III flux ratio was increased from 1 to 6, the nanowires showed a change in morphology from outward tapering to straight, and eventually to inward tapering. The morphologies of the self-assisted GaP nanowires are well described by a simple kinetic equation for the nanowire radius versus the position along the nanowire axis...
March 6, 2018: Nanotechnology
Salah Awel, Richard A Kirian, Max O Wiedorn, Kenneth R Beyerlein, Nils Roth, Daniel A Horke, Dominik Oberthür, Juraj Knoska, Valerio Mariani, Andrew Morgan, Luigi Adriano, Alexandra Tolstikova, P Lourdu Xavier, Oleksandr Yefanov, Andrew Aquila, Anton Barty, Shatabdi Roy-Chowdhury, Mark S Hunter, Daniel James, Joseph S Robinson, Uwe Weierstall, Andrei V Rode, Saša Bajt, Jochen Küpper, Henry N Chapman
High-resolution Bragg diffraction from aerosolized single granulovirus nanocrystals using an X-ray free-electron laser is demonstrated. The outer dimensions of the in-vacuum aerosol injector components are identical to conventional liquid-microjet nozzles used in serial diffraction experiments, which allows the injector to be utilized with standard mountings. As compared with liquid-jet injection, the X-ray scattering background is reduced by several orders of magnitude by the use of helium carrier gas rather than liquid...
February 1, 2018: Journal of Applied Crystallography
Colin J Clark, Holger J Pletsch, Jason Wu, Lucas Guillemot, Matthew Kerr, Tyrel J Johnson, Fernando Camilo, David Salvetti, Bruce Allen, David Anderson, Carsten Aulbert, Christian Beer, Oliver Bock, Andres Cuéllar, Heinz-Bernd Eggenstein, Henning Fehrmann, Michael Kramer, Shawn A Kwang, Bernd Machenschalk, Lars Nieder, Markus Ackermann, Marco Ajello, Luca Baldini, Jean Ballet, Guido Barbiellini, Denis Bastieri, Ronaldo Bellazzini, Elisabetta Bissaldi, Roger D Blandford, Elliott D Bloom, Raffaella Bonino, Eugenio Bottacini, Terri J Brandt, Johan Bregeon, Philippe Bruel, Rolf Buehler, Toby H Burnett, Sara Buson, Rob A Cameron, Regina Caputo, Patrizia A Caraveo, Elisabetta Cavazzuti, Claudia Cecchi, Eric Charles, Alexandre Chekhtman, Stefano Ciprini, Lynn R Cominsky, Denise Costantin, Sara Cutini, Filippo D'Ammando, Andrea De Luca, Rachele Desiante, Leonardo Di Venere, Mattia Di Mauro, Niccolò Di Lalla, Seth W Digel, Cecilia Favuzzi, Elizabeth C Ferrara, Anna Franckowiak, Yasushi Fukazawa, Stefan Funk, Piergiorgio Fusco, Fabio Gargano, Dario Gasparrini, Nico Giglietto, Francesco Giordano, Marcello Giroletti, Germán A Gomez-Vargas, David Green, Isabelle A Grenier, Sylvain Guiriec, Alice K Harding, John W Hewitt, Deirdre Horan, Guðlaugur Jóhannesson, Shiki Kensei, Michael Kuss, Giovanni La Mura, Stefan Larsson, Luca Latronico, Jian Li, Francesco Longo, Francesco Loparco, Michael N Lovellette, Pasquale Lubrano, Jeffrey D Magill, Simone Maldera, Alberto Manfreda, Mario N Mazziotta, Julie E McEnery, Peter F Michelson, Nestor Mirabal, Warit Mitthumsiri, Tsunefumi Mizuno, Maria Elena Monzani, Aldo Morselli, Igor V Moskalenko, Eric Nuss, Takashi Ohsugi, Nicola Omodei, Monica Orienti, Elena Orlando, Michele Palatiello, Vaidehi S Paliya, Francesco de Palma, David Paneque, Jeremy S Perkins, Massimo Persic, Melissa Pesce-Rollins, Troy A Porter, Giacomo Principe, Silvia Rainò, Riccardo Rando, Paul S Ray, Massimiliano Razzano, Anita Reimer, Olaf Reimer, Roger W Romani, Pablo M Saz Parkinson, Carmelo Sgrò, Eric J Siskind, David A Smith, Francesca Spada, Gloria Spandre, Paolo Spinelli, Jana B Thayer, David J Thompson, Diego F Torres, Eleonora Troja, Giacomo Vianello, Kent Wood, Matthew Wood
Millisecond pulsars (MSPs) are old neutron stars that spin hundreds of times per second and appear to pulsate as their emission beams cross our line of sight. To date, radio pulsations have been detected from all rotation-powered MSPs. In an attempt to discover radio-quiet gamma-ray MSPs, we used the aggregated power from the computers of tens of thousands of volunteers participating in the Einstein@Home distributed computing project to search for pulsations from unidentified gamma-ray sources in Fermi Large Area Telescope data...
February 2018: Science Advances
K Saha, V Chandrasekaran, O Heber, M A Iron, M L Rappaport, D Zajfman
Isomerization and carbon chemistry in the gas phase are key processes in many scientific studies. Here we report on the isomerization process from linear [Formula: see text] to its monocyclic isomer. [Formula: see text] ions were trapped in an electrostatic ion beam trap and then excited with a laser pulse of precise energy. The neutral products formed upon photoexcitation were measured as a function of time after the laser pulse. It was found using a statistical model that, although the system is excited above its isomerization barrier energy, the actual isomerization from linear to monocyclic conformation takes place on a very long time scale of up to hundreds of microseconds...
March 2, 2018: Nature Communications
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"