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Sample records for hom coupler design

  1. HOM Couplers for CERN SPL Cavities

    CERN Document Server

    Papke, Kai; Van Rienen, U

    2013-01-01

    Higher-Order-Modes (HOMs) may affect beam stability and refrigeration requirements of superconducting proton linacs such as the SPL, which is studied at CERN as the driver for future neutrino facilities. In order to limit beam-induced HOM effects, CERN considers the use of HOM couplers on the cut-off tubes of the 5-cell superconducting cavities. These couplers consist of resonant antennas shaped as loops or probes, which are designed to couple to modes of a specific frequency range. In this paper the design process is presented and a comparison is made between various design options for the medium and high-beta SPL cavities, both operating at 704.4 MHz. The RF characteristics and thermal behaviour of the various designs are discussed.

  2. FPC and Hi-Pass Filter HOM Coupler Design for the RF Dipole Crab Cavity for the LHC HiLumi Upgrade

    CERN Document Server

    Li, Z; Delayen, Jean Roger; De Silva, S U; Park, HyeKyoung; Olave, R G

    2015-01-01

    A 400-MHz compact RF dipole (RFD) crab cavity design was jointly developed by Old Dominion University and SLAC under the support of US LARP program for the LHC HiLumi upgrade. The RFD cavity design is consisted of a rounded-square tank and two ridged deflecting poles, operating with a TE11-like dipole mode, which is the lowest mode of the cavity. A prototype RFD cavity is being manufactured and will be tested on the SPS beam line at CERN. The coaxial fundamental Power Coupler (FPC) of the prototype cavity was re-optimized to minimizing the power heating on the coupler internal antenna. A hi-pass filter HOM damping coupler was developed to achieve the required wakefield damping while maintaining a compact size to fit into the beam line space. In this paper, we will discuss the details of the RF optimization and tolerance analyses of the FPC and HOM couplers.

  3. ANSYS modeling of thermal contraction of SPL HOM couplers during cool-down

    CERN Document Server

    Papke, K

    2016-01-01

    During the cool-down the HOM coupler as well as the cavity inside the cryo module experience a thermal contraction. For most materials between room temperature and liquid helium temperatures, the changes in dimension are in the order of a few tenths of a percent change in volume. This paper presents the effect of thermal contraction on the RF transmission behavior of HOM couplers, and in particular the influence on its notch filter. Furthermore the simulation process with APDL is explained in detail. Conclusions about the necessary tuning range of the notch filter are made which is especially a concern for couplers with only notch filter.

  4. Engineering Study of Crab Cavity HOM Couplers for LHC High Luminosity Upgrade

    CERN Document Server

    Park, Hyekyung; Delayen, Jean Roger; De Silva, S U; Li, Z; Nicol, T H; Capelli, Teddy; Templeton, Niklas John

    2015-01-01

    The LHC is planning to employ crab cavities for the high luminosity upgrade. Old Dominion University and SLAC National Laboratory are developing a crab cavity completed with the HOM damping couplers [1]. The HOM couplers are coaxial type and perform over broadband up to 2 GHz. The amount of extracted power requires active cooling using liquid helium. The electromagnetic study has provided expected power dissipation on the coupler. Correlations between the fabrication tolerance and its damping performance have been studied and the results are providing guidelines on how to manufacture the HOM couplers. This paper summarizes the engineering studies; mechanical strength as a part of pressure system, thermal stability, and fabrication method to ensure the required tolerance.

  5. Electromagnetic fields and beam dynamics simulation for the superstructure of tesla linear collider considering field asymmetry caused by hom and power couplers

    CERN Document Server

    Lalayan, M V; Sobenin, N P; Shvedunov, V I; Zavadtsev, A A; Dohlus, M

    2001-01-01

    Some features of accelerating section field computation presented by the development of power and high order mode couplers for TESLA linear collider are considered. The devices mentioned produce electromagnetic field asymmetry in the beam area, thus causing transverse kick. For this kick and its influence on beam under acceleration parameters estimation the dynamics modelling calculations were done. 3D-simulation code MAFIA was used for field computation. These data were further used in beam dynamics calculations by means of TRMTrace code. Standing wave mode was simulated while considering HOM couplers, and travelling wave in case of power couplers. Transverse kicks and focussing forces are calculated for one HOM coupler design and two coaxial FM couplers.

  6. HOM damping properties of fundamental power couplers in the superconducting electron gun of the energy recovery LINAC at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Hammons, L.; Hahn, H.

    2011-03-28

    Among the accelerator projects under construction at the Relativistic Heavy Ion Collider (RHIC) is an R and D energy recovery LINAC (ERL) test facility. The ERL includes both a five-cell superconducting cavity as well as a superconducting, photoinjector electron gun. Because of the high-charge and high-current demands, effective higher-order mode (HOM) damping is essential, and several strategies are being pursued. Among these is the use of the fundamental power couplers as a means for damping some HOMs. Simulation studies have shown that the power couplers can play a substantial role in damping certain HOMs, and this presentation discusses these studies along with measurements.

  7. Hom.

    Directory of Open Access Journals (Sweden)

    M. D. Petruševski

    1979-12-01

    Full Text Available On souligne d'abord les mérites de feu Milan Grošelj, excellent philologue et linguiste, dans l'interpré­ tation d'un nombre rernarquable de gloses d'Hésychios et dans ses études linguistiques concernant surtout l'étymo­ logie d'un assez grand nornbre de mots grecs et latins. On en cite quelques exemples, comme ainsi que l'interprétation du terme homérique. On cite aussi quelques interpretations de mots et formes mycéniens, proposées par l'auteur lui-même de l'article précédent, comme p. ex. celle du toponyme "pylien" pe-to-no (avec son ethnique pe-ti-ni-jo, plus tard (à l'epoque hellénistique et romaine connu sous la forme(cp. les formes corradicales Pedna, de Petna, îlat près de Lesbos, ville de Pisidie en Asie Mineure (mont et ville de Crète et corradical de(avec l'alternance connue -r/n- des langues indo-européennes et on en propose une étymologie pet- "tomber, s'écrouler". En ce qui concerne l'interprétation du terme homérique l'auteur part de l'hypothèse de C.J. Ruijgh (L'élément achéen de la langue épique, 163:  22° que le verbe n'a un emploi normal que dans la langue épique, c'.-à-d. chez Homère, et dans le dialecte arcado-cypriote, et il pense que n'est pasune forme neutre de l'adjectif: (comparée avec sscr. upa-dŕš- f. "Anblick", comme cela est interprété chez E. Schwyzer, Gr. Gr. I 621 et E. Risch, Wortbild. d. ho­mer. Spr. §  128 a, mais une forme cypriote de l'adverbe simplifiee en (comme dans l'ancien dialecte "achéen" de l'époque mycé nli enne et assimilée devant , comme dans les deux exemples connus des inscriptions Cypriotes.

  8. LHC Crab Cavity Coupler Test Boxes

    CERN Document Server

    Mitchell, James; Burt, Graeme; Calaga, Rama; Macpherson, Alick; Montesinos, Eric; Silva, Subashini; Tutte, Adam; Xiao, Binping

    2016-01-01

    The LHC double quarter wave (DQW) crab cavities have two different types of Higher Order Mode (HOM) couplers in addition to a fundamental power coupler (FPC). The FPC requires conditioning, so to achieve this we have designed a radio-frequency (RF) quarter wave resonator to provide high transmission between two opposing FPCs. For the HOM couplers we must ensure that the stop-band filter is positioned at the cavity frequency and that peak transmission occurs at the same frequencies as the strongest HOMs. We have designed two test boxes which preserve the cavity spectral response in order to test the couplers.

  9. General lossless planar coupler design algorithms.

    Science.gov (United States)

    Vance, Rod

    2015-08-01

    This paper reviews and extends two classes of algorithms for the design of planar couplers with any unitary transfer matrix as design goals. Such couplers find use in optical sensing for fading free interferometry, coherent optical network demodulation, and also for quantum state preparation in quantum optical experiments and technology. The two classes are (1) "atomic coupler algorithms" decomposing a unitary transfer matrix into a planar network of 2×2 couplers, and (2) "Lie theoretic algorithms" concatenating unit cell devices with variable phase delay sets that form canonical coordinates for neighborhoods in the Lie group U(N), so that the concatenations realize any transfer matrix in U(N). As well as review, this paper gives (1) a Lie theoretic proof existence proof showing that both classes of algorithms work and (2) direct proofs of the efficacy of the "atomic coupler" algorithms. The Lie theoretic proof strengthens former results. 5×5 couplers designed by both methods are compared by Monte Carlo analysis, which would seem to imply atomic rather than Lie theoretic methods yield designs more resilient to manufacturing imperfections.

  10. Achromatic waveguide input/output coupler design.

    Science.gov (United States)

    Spaulding, K E; Morris, G M

    1991-03-20

    An investigation into methods for achromatizing the coupling angle characteristics of waveguide input/output couplers is described. The basic approach involves correcting the inherent angular dispersion of conventional waveguide couplers with a diffraction grating. Two configurations are analyzed in detail: a hybrid prism/grating coupler and a double grating coupler. Expressions are derived for values of the grating parameters that produce achromatic coupling. A method is also presented to predict the achromatic wavelength range and maximize it with the available degrees of freedom. For a coupling angle tolerance of 0.005 degrees , it is found that with double grating couplers achromatic wavelength ranges of the order of 10 nm can be obtained, and that with prism/grating couplers this range can be as large as 200 nm.

  11. Five-cell superconducting RF module with a PBG coupler cell: design and cold testing of the copper prototype

    Energy Technology Data Exchange (ETDEWEB)

    Arsenyev, Sergey Andreyevich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Simakov, Evgenya Ivanovna [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Shchegolkov, Dmitry [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boulware, Chase [Niowave, Lansing, MI (United States); Grimm, Terry [Niowave, Lansing, MI (United States); Rogacki, Adam [Niowave, Lansing, MI (United States)

    2015-04-29

    We report the design and experimental data for a copper prototype of a superconducting radio-frequency (SRF) accelerator module. The five-cell module has an incorporated photonic band gap (PBG) cell with couplers. The purpose of the PBG cell is to achieve better higher order mode (HOM) damping, which is vital for preserving the quality of high-current electron beams. Better HOM damping raises the current threshold for beam instabilities in novel SRF accelerators. The PBG design also increases the real-estate gradient of the linac because both HOM damping and the fundamental power coupling can be done through the PBG cell instead of on the beam pipe via complicated end assemblies. First, we will discuss the design and accelerating properties of the structure. The five-cell module was optimized to provide good HOM damping while maintaining the same accelerating properties as conventional elliptical-cell modules. We will then discuss the process of tuning the structure to obtain the desired accelerating gradient profile. Finally, we will list measured quality factors for the accelerating mode and the most dangerous HOMs.

  12. SIMULATIONS AND MEASUREMENTS OF A HEAVILY HOM-DAMPED MULTI-CELL SRF CAVITY

    Energy Technology Data Exchange (ETDEWEB)

    Haipeng Wang; Robert Rimmer; Frank Marhauser

    2007-07-02

    After an initial cavity shape optimization [1] and cryomodule development [2] for an Ampere-class FEL ERL, we have simulated a complete 5-cell high-current (HC) cavity structure with six waveguide (WG) couplers for Higher Order Mode (HOM) damping and fundamental power coupling. The time-domain wakefield simulations of the MAFIA codes have been used to calculate the cavities broadband HOM impedance spectrum. Microwave Studio (MWS) has also been used to evaluate the external Q of the fundamental power coupler (FPC) and the R/Qs of the HOMs. A half scale 1497MHz single-cell model cavity and a 5-cell copper cavity including dummy HOM WG loads were fabricated to bench measure and confirm the design performance. Details of the multi-beam wakefield simulations, the HOM damping measurements and multi-peak data fitting analysis techniques are presented.

  13. HOM power in FCC-ee cavities

    CERN Document Server

    Karpov, Ivan; Chapochnikova, Elena

    2018-01-01

    This Note summarizes the results of the power loss calculations for FCC-ee machines with 400.79 MHz cavity options. The requirements for the single-cell cavity design and for the operation with beam are obtained from the results for the high-current FCC-ee machine (Z). For other machines the power loss is sufficiently low and can be absorbed and extracted by foreseen HOM couplers.

  14. Tolerance study for the components of the probe-type and hook-type Higher Order Mode couplers for the HL-LHC 800 MHz harmonic system

    CERN Document Server

    Blanco, Esteban

    2016-01-01

    A superconducting 800 MHz second harmonic RF system is one of the considered options as a Landau damping mechanism for HiLumi LHC. The Higher Order Mode (HOM) coupler designs require tight manufacturing tolerances in order to operate at the design specifications. The project consists of defining the mechanical tolerances for the different components of both the probe-type and hook-type HOM coupler. With the use of electromagnetic field simulation software it is possible to identify the critical components of the HOM coupler and to quantify their respective tolerances. The obtained results are discussed in this paper.

  15. Design and characterization of dielectric-loaded plasmonic directional couplers

    DEFF Research Database (Denmark)

    Stær, Tobias Holmgaard; Chen, Zhuo; Bozhevolnyi, Sergey

    2009-01-01

    Ultracompact directional couplers (DCs) based on dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs) are analyzed using the effective index method (EIM), with the coupling, both in the parallel interaction region and in- and out-coupling regions, being taken into account. Near......-field characterization of fabricated DCs performed with a scanning near-field optical microscope verifies the applicability of the EIM in the analysis and design of DLSPPW-based wavelength-selective DCs. The design approach applicable to a large variety of integrated optical waveguides is developed, enabling...

  16. Comparison of coaxial higher order mode couplers for the CERN Superconducting Proton Linac study

    CERN Document Server

    AUTHOR|(CDS)2085329; Gerigk, Frank; Van Rienen, Ursula

    2017-01-01

    Higher order modes (HOMs) may affect beam stability and refrigeration requirements of superconducting proton linacs such as the Superconducting Proton Linac, which is studied at CERN. Under certain conditions beam-induced HOMs can accumulate sufficient energy to destabilize the beam or quench the superconducting cavities. In order to limit these effects, CERN considers the use of coaxial HOM couplers on the cutoff tubes of the 5-cell superconducting cavities. These couplers consist of resonant antennas shaped as loops or probes, which are designed to couple to potentially dangerous modes while sufficiently rejecting the fundamental mode. In this paper, the design process is presented and a comparison is made between various designs for the high-beta SPL cavities, which operate at 704.4 MHz. The rf and thermal behavior as well as mechanical aspects are discussed. In order to verify the designs, a rapid prototype for the favored coupler was fabricated and characterized on a low-power test-stand.

  17. Higher Order Mode (HOM) Impedance and Damping Study for the LHC Capture Cavity

    CERN Document Server

    Linnecar, Trevor Paul R; Tückmantel, Joachim; CERN. Geneva. SPS and LHC Division

    2001-01-01

    To investigate the higher order mode, HOM, damping in the LHC 200MHz ACN cavity when using four HOM couplers, simulations have been done by both 3-D frequency domain and time domain methods. These simulations have previously been used in other studies of HOM damped cavities and shown to be effective by comparing measurement and simulation results[1] [2]. Using these methods the impedance spectrum of the HOM modes in the cavity before and after damping has been obtained. From this, detailed information about the HOM coupler's contribution to HOM damping can be obtained. The distribution and magnitude of some potentially dangerous HOM modes in the ACN cavity have been found.

  18. A Four-Cell Periodically HOM-Damped RF Cavity for High Current Accelerators

    CERN Document Server

    Wu, G; Wang, H

    2004-01-01

    A periodically Higher Order Mode (HOM) damped RF cavity is a weakly coupled multi-cell RF cavity with HOM couplers periodically mounted between the cells. It was studied as an alternative RF structure between the single cell cavity and superstructure cavity in high beam current application requiring strong damping of the HOMs. The acceleration mode in this design is the lowest frequency mode (Zero Mode) in the pass band, in contrast to the traditional “π” acceleration mode. The acceleration mode of a four-cell Zero Mode cavity has been studied along with the monopole and dipole HOMs. Some HOMs have been modeled in HFSS with waveguide HOM couplers, which were subsequently verified by MAFIA time domain analysis. To understand the tuning challenge for the weakly coupled cavity, ANSYS and SUPERFISH codes were used to simulate the cavity frequency sensitivity and field flatness change within proper tuning range, which will influence the design of the tuner structure. This paper presen...

  19. Design and optimization of mechanically down-doped terahertz fiber directional couplers

    DEFF Research Database (Denmark)

    Bao, Hualong; Nielsen, Kristian; Rasmussen, Henrik K.

    2014-01-01

    We present a thorough practical design optimization of broadband low loss, terahertz (THz) photonic crystal fiber directional couplers in which the two cores are mechanically down-doped with a triangular array of air holes. A figure of merit taking both the 3-dB bandwidth and loss of the coupler...

  20. Design and Optimization of Air-Doped 3-dB Terahertz Fiber Directional Couplers

    DEFF Research Database (Denmark)

    Bao, Hualong; Nielsen, Kristian; Rasmussen, Henrik K.

    2014-01-01

    We present a thorough practical design optimization of broadband low loss, terahertz (THz) photonic crystal fiber directional couplers in which the two cores are mechanically down- doped with a triangular array of air holes.......We present a thorough practical design optimization of broadband low loss, terahertz (THz) photonic crystal fiber directional couplers in which the two cores are mechanically down- doped with a triangular array of air holes....

  1. Design of coupler for the NSLS-II storage ring superconducting RF cavity

    Energy Technology Data Exchange (ETDEWEB)

    Yeddulla, M.; Rose, J.

    2011-03-28

    NSLS-II is a 3GeV, 500mA, high brightness, 1 MW beam power synchrotron facility that is designed with four superconducting cavities working at 499.68 MHz. To operate the cavities in over-damped coupling condition, an External Quality Factor (Qext) of {approx}65000 is required. We have modified the existing coupler for the CESR-B cavity which has a Qext of {approx}200,000 to meet the requirements of NSLS-II. CESR-B cavity has an aperture coupler with a coupler 'tongue' connecting the cavity to the waveguide. We have optimized the length, width and thickness of the 'tongue' as well as the width of the aperture to increase the coupling using the three dimensional electromagnetic field solver, HFSS. Several possible designs will be presented. We have modified the coupler of the CESR-B cavity to be used in the storage ring at the NSLS-II project using HFSS and verified using CST Microwave Studio. Using a combination of increasing the length and width of the coupler tongue and increasing the width of the aperture, the external Q of the cavity coupler was decreased to {approx}65000 as required for the design of the NSLS-II storage ring design.

  2. Design of Dual-Band Two-Branch-Line Couplers with Arbitrary Coupling Coefficients in Bands

    Directory of Open Access Journals (Sweden)

    I. Prudyus

    2014-12-01

    Full Text Available A new approach to design dual-band two-branch couplers with arbitrary coupling coefficients at two operating frequency bands is proposed in this article. The method is based on the usage of equivalent subcircuits input reactances of the even-mode and odd-mode excitations. The exact design formulas for three options of the dual-band coupler with different location and number of stubs are received. These formulas permit to obtain the different variants for each structure in order to select the physically realizable solution and can be used in broad range of frequency ratio and power division ratio. For verification, three different dual-band couplers, which are operating at 2.4/3.9 GHz with different coupling coefficients (one with 3/6 dB, and 10/3 dB two others are designed, simulated, fabricated and tested. The measured results are in good agreement with the simulated ones.

  3. RF Coupler Design for the TRIUMF ISAC-II Superconducting Quarter Wave Resonator

    CERN Document Server

    Poirier, R L; Harmer, P; Laxdal, R E; Mitra, A K; Sekatchev, I; Waraich, B; Zvyagintsev, V

    2004-01-01

    An RF Coupler for the ISAC-II medium beta (β=0.058 and 0.071) superconducting quarter wave resonators was designed and tested at TRIUMF. The main goal of this development was to achieve stable operation of superconducting cavities at high acceleration gradients and low thermal load to the helium refrigeration system. The cavities will operate at 6 MV/m acceleration gradient in overcoupled mode at a forward power 200 W at 106 MHz. The overcoupling provides ±20 Hz cavity bandwidth, which improves the stability of the RF control system for fast helium pressure fluctuations, microphonics and environmental noise. Choice of materials, cooling with liquid nitrogen, aluminum nitride RF window and thermal shields insure a small thermal load on the helium refrigeration system by the Coupler. An RF finger contact which causedμdust in the coupler housing was eliminated without any degradation of the coupler performance. RF and thermal calculations, design and test results on the coupler are p...

  4. Research on Design of Plate-type Electromagnetic Coupler in Underwater Inductive Power Transmission

    Directory of Open Access Journals (Sweden)

    Qu Li-yan

    2015-01-01

    Full Text Available Magnetic coupler has a good application in the field of underwater sensor. Magnetic coupler at work, interference by underwater complex situation, stability and efficiency of charging device of the gap is larger fluctuations. The traditional electromagnetic coupling is charging for the stability of the clearance to demand higher. Charging for underwater, as a result of the existence of ocean currents, electromagnetic coupling clearance may not remain very stable. When there is deviation gap, a larger electromagnetic coupling performance deviation. On this particular problem, it puts forward the design method of a new type of plate type electromagnetic coupling. First of all, the leakage inductance of the finite element method to calculate system and excitation inductance, establish electromagnetic coupler with compensation capacitor equivalent circuit, and the primary circuit and secondary circuit was designed. On the basis, the voltage gain and efficiency of the system are carrying on the theoretical derivation and calculation. The simulation experimental results show that the magnetic coupler has a stable voltage gain and charging efficiency, when the partial core within 10 mm, voltage gain remains steady at 5.8%, efficiency remain at around 90%.

  5. Flat-Passband 3 × 3 Interleaving Filter Designed With Optical Directional Couplers in Lattice Structure

    Science.gov (United States)

    Wang, Qi Jie; Zhang, Ying; Soh, Yeng Chai

    2005-12-01

    This paper presents a novel lattice optical delay-line circuit using 3 × 3 directional couplers to implement three-port optical interleaving filters. It is shown that the proposed circuit can deliver three channels of 2pi/3 phase-shifted interleaving transmission spectra if the coupling ratios of the last two directional couplers are selected appropriately. The other performance requirements of an optical interleaver can be achieved by designing the remaining part of the lattice circuit. A recursive synthesis design algorithm is developed to calculate the design parameters of the lattice circuit that will yield the desired filter response. As illustrative examples, interleavers with maximally flat-top passband transmission and with given transmission performance on passband ripples and passband bandwidth, respectively, are designed to verify the effectiveness of the proposed design scheme.

  6. HOM characterization for beam diagnostics at the european XFEL injector

    CERN Document Server

    Baboi, Nicoletta; Shi, Liangliang; Wamsat, Thomas, DESY; Jones, Roger M; Joshi, Nirav

    2017-01-01

    Higher Order Modes (HOM) excited by bunched electron beams in accelerating cavities carry information about the beam position and phase. This principle is used at the FLASH facility, at DESY, for beam position monitoring in 1.3 and 3.9 GHz cavities. Dipole modes, which depend on the beam offset, are used. Similar monitors are now under design for the European XFEL. In addition to beam position, the beam phase with respect to the accelerating RF will be monitored using monopole modes from the first higher order monopole band. The HOM signals are available from two couplers installed on each cavity. Their monitoring will allow the on-line tracking of the phase stability over time, and we anticipate that it will improve the stability of the facility. As part of the monitor designing, the HOM spectra in the cavities of the 1.3 and 3.9 GHz cryo-modules installed in the European XFEL injector have been measured. This paper will present their dependence on the beam position. The variation in the modal distribution f...

  7. The Design of Polymer Planar Optical Triplexer with MMI Filter and Directional Coupler

    Directory of Open Access Journals (Sweden)

    V. Jerabek

    2013-12-01

    Full Text Available Optical bidirectional WDM transceiver is a key component of the Passive Optical Network of the Fiber to the Home topology. Essential parts of such transceivers are filters that combine multiplexing and demultiplexing function of optical signal (triplexing filters. In this paper we report about a design of a new planar optical multi-wavelength selective system triplexing filter, which combines a multimode interference filter with directional coupler based on the epoxy polymer SU-8 on Si/SiO2 substrate. The optical triplexing filter was designed using the Beam Propagation Method. The aim of this project was to optimize the triplexing filter optical parameters and to minimize the planar optical wavelength selective system dimensions. The multimode interference filter was used for separation of downstream optical signal in designed optoelectronic integrated WDM transceiver. The directional coupler was used for adding of upstream optical signal.

  8. Ceramic Power Extractor Design at 15.6 GHz

    CERN Document Server

    Smirnov, Alexei Yu; Yi, Rong; Yu, David

    2005-01-01

    Power extractor and coupler designs developed for an experiment planned at the 12th beam harmonic of the upgraded Advanced Wakefield Accelerator (AWA) facility is described. New features are an upstream HOM dielectric damper with additional tapering, and a single-port coupler considered in two variants. Performance analysis includes coupler geometric tolerances, overvoltage, dipole mode wake and BBU; and wakefield losses induced in the damper.

  9. Broadband optical waveguide couplers with arbitrary coupling ratios designed using a genetic algorithm.

    Science.gov (United States)

    Fu, Po-Han; Tu, Yi-Chou; Huang, Ding-Wei

    2016-12-26

    In this work, we present a generalized design of broadband optical waveguide couplers with arbitrary coupling ratios on the silicon-on-insulator platform. The device is segmented into 34 short sections, where the propagation constant and the coupling coefficient of each section are viewed as variables during the optimization process. The optimal variable combination is determined by a genetic algorithm. We can achieve a performance superior to that of other design methods with fewer degrees of freedom. For 75%/25%, 50%/50%, 25%/75%, and 0%/100% couplers, the device lengths are 34 μm and the ±2% bandwidths are all in excess of 100 nm at the central wavelength of 1580 nm.

  10. Design, simulations, and conditioning of 500 kW fundamental power couplers for a superconducting rf gun

    Directory of Open Access Journals (Sweden)

    Wencan Xu

    2012-07-01

    Full Text Available A half-cell superconducting rf electron gun is designed to provide 0.5 A, 2 MeV beam for the Brookhaven National Laboratory R&D Energy Recovery Linac. Total rf power of 1 MW must be delivered to beam to meet the beam current and energy specifications, resulting in very strong coupling. Two opposing fundamental power couplers (FPCs are employed to minimize the transverse kick to beam traversing the structure and to halve the power through the coupler. A single-window coaxial coupler has been designed to meet the average power and rf coupling requirements. The coupler features a planar beryllia rf window for better handling high thermal stresses and a “pringle”-shaped tip of the antenna for enhancing rf coupling. Two FPCs have been fabricated and tested in preparation for the gun cryomodule assembly. A room-temperature test stand was used for conditioning couplers in full reflection regime with variable phase of the reflecting wave. The couplers were tested up to 250 kW in pulse mode and 125 kW in cw mode at different settings of the reflecting wave phase to expose all rf surfaces along the couplers to high fields. Several multipacting barriers were encountered and successfully processed away. The rf power levels, at which multipacting was found, match well those found in computer simulations.

  11. Comparison of coaxial higher order mode couplers for the CERN Superconducting Proton Linac study

    Directory of Open Access Journals (Sweden)

    K. Papke

    2017-06-01

    Full Text Available Higher order modes (HOMs may affect beam stability and refrigeration requirements of superconducting proton linacs such as the Superconducting Proton Linac, which is studied at CERN. Under certain conditions beam-induced HOMs can accumulate sufficient energy to destabilize the beam or quench the superconducting cavities. In order to limit these effects, CERN considers the use of coaxial HOM couplers on the cutoff tubes of the 5-cell superconducting cavities. These couplers consist of resonant antennas shaped as loops or probes, which are designed to couple to potentially dangerous modes while sufficiently rejecting the fundamental mode. In this paper, the design process is presented and a comparison is made between various designs for the high-beta SPL cavities, which operate at 704.4 MHz. The rf and thermal behavior as well as mechanical aspects are discussed. In order to verify the designs, a rapid prototype for the favored coupler was fabricated and characterized on a low-power test-stand.

  12. Magnetic Shielding Design for Coupler of Wireless Electric Vehicle Charging Using Finite Element Analysis

    Science.gov (United States)

    Zhao, W. N.; Yang, X. J.; Yao, C.; Ma, D. G.; Tang, H. J.

    2017-10-01

    Inductive power transfer (IPT) is a practical and preferable method for wireless electric vehicle (EV) charging which proved to be safe, convenient and reliable. Due to the air gap between the magnetic coupler, the magnetic field coupling decreases and the magnetic leakage increases significantly compared to traditional transformer, and this may lead to the magnetic flux density around the coupler more than the safety limit for human. So magnetic shielding should be adding to the winding made from litz wire to enhance the magnetic field coupling effect in the working area and reduce magnetic field strength in non-working area. Magnetic shielding can be achieved by adding high-permeability material or high-conductivity material. For high-permeability material its magnetic reluctance is much lower than the surrounding air medium so most of the magnetic line goes through the high-permeability material rather than surrounding air. For high-conductivity material the eddy current in the material can produce reverse magnetic field to achieve magnetic shielding. This paper studies the effect of the two types of shielding material on coupler for wireless EV charging and designs combination shielding made from high-permeability material and high-conductivity material. The investigation of the paper is done with the help of finite element analysis.

  13. Design, fabrication, and characterisation of fully etched TM grating coupler for photonic integrated system-in-package

    Science.gov (United States)

    Gili-de-Villasante, Oriol; Tcheg, Paul; Wang, Bei; Suna, Alpaslan; Giannoulis, Giannis; Lazarou, Ioannis; Apostolopoulos, Dimitrios; Avramopoulos, Hercules; Pleros, Nikos; Baus, Matthias; Karl, Matthias; Tekin, Tolga

    2012-06-01

    Grating couplers are the best solution for testing nano-photonic circuits. Their main benefit is that they allow access via an optical fiber from the top and therefore there is no need to dice the chip and prepare the facets crucially. In the PLATON project grating couplers were designed to couple TM mode into and out of the SOI waveguides. Simulations came up with a grating coupler layout capable of theoretical coupling losses lower than 3dB for 1550 nm in TM configuration. A fully etched grating structure was chosen for fabrication simplicity and the optimal filling factor was found. The structures were fabricated using proximity error correction (PEC) and show a uniform coupling efficiency for all couplers. Therefore they are well-suited for all applications which demand for stable fiber-to-chip coupling. The spectral response of the structures was measured from 1500 to 1580 nm with 2 nm step and measuring the fiber-tofiber losses of three straight waveguides equipped with three grating couplers with different gap widths. The optimal grating period exhibits adequate coupling losses of 3.23 dB per coupler at 1557 nm, being therefore the most promising design.

  14. A new design of a directional coupler for high order mode multiplexing in few mode fibers

    Science.gov (United States)

    Trichili, Abderrahmen; Ben Salem, Amine; Cherif, Rim; Zghal, Mourad; Forbes, Andrew

    2014-05-01

    We propose a new and versatile design of a directional coupler able to generate and multiplex high order modes in few mode fibers. The designed device can selectively generate five high order modes and multiplex them in a few mode fiber with an overall insertion loss not exceeding 3dB at the telecommunication wavelength λ = 1550 nm. The mode dependent loss is found to be weakly dependent to the wavelength. The proposed device is very promising for high order mode multiplexing and suitable for high bit-rate optical communication systems.

  15. (abstract) The Design of a Benign Fail-safe Mechanism Using a Low-melting-point Metal Alloy Coupler

    Science.gov (United States)

    Blomquist, Richard S.

    1995-01-01

    Because the alpha proton X ray spectrometer (APXS) sensor head on the Mars Pathfinder rover, Sojourner, is placed on Martian soil by the deployment mechanism (ADM), the rover would be crippled if the actuator fails when the mechanism is in its deployed position, as rover ground clearance is then reduced to zero. This paper describes the unique fail-safe mounted on the ADM, especially the use of a low-temperature-melting alloy as a coupler device. The final form of the design is a low-melting-point metal pellet coupler, made from Cerrobend, in parallel with a Negator spring pack. In its solid state, the metal rigidly connects the driver (the actuator) and the driven part (the mechanism). When commanded, a strip heater wrapped around the coupler melts the metal pellet (at 60(deg)C), allowing the driven part to turn independent of the driver. The Negator spring retracts the mechanism to its fully stowed position. This concept meets all the design criteria, and provides an added benefit. When the metal hardens the coupler once again rigidly connects the actuator and the mechanism. The concept presented here can easily be applied to other applications. Anywhere release devices are needed, low-melting-point couplers can be considered. The issues to be concerned with are thermal isolation, proper setting of the parts before actuation, and possible outgassing concerns. However, when these issues are overcome, the resulting release mechanism can promise to be the most light, simple, power conserving alternative available.

  16. Design of short length and C+L-band mismatched optical coupler with waveguide weighted by the Blackman function

    Science.gov (United States)

    Chen, Chi-Feng; Ku, Yun-Sheng; Kung, Tsu-Te

    2009-01-01

    A mismatched optical coupler with waveguide weighted by the Blackman function is numerically investigated in the demand of short length, C+L-band, and low crosstalk. Utilizing the full factorial design, the structure parameters of coupling waveguide are obtained by beam propagation method. In the condition of crosstalk of -35 dB, the mismatched optical coupler with proper selected waveguide structure parameters is found to have a coupling length of 3.60 mm in the transmission wavelength ranges of C+L-band (1.53-1.61 μm). Obviously, the selection and design of waveguide structure are very important to satisfy the qualities of a mismatched optical coupler for the demand of short length, broad bandwidth, and low crosstalk.

  17. Design of a 300 GHz Broadband TWT Coupler and RF-Structure

    CERN Document Server

    Krawczyk, F L

    2004-01-01

    Recent LANL activities in millimeter wave structures focus on 94 and 300 GHz structures. They aim at power generation from low power (100–2000 W) with a round electron beam (120 kV, 0.1–1.0 A) to high power (2–100 kW) with a sheet beam structure (120 kV, 20 A). Applications cover basic research, radar and secure communications and remote sensing of biological and chemical agents. In this presentation the design and cold-test measurements of a 300 GHz RF-structure with a broadband (>6% bandwidth) power coupler are presented. The design choice of two input/output waveguides, a special coupling region and the structure parameters themselves are presented. As a benchmark also a scaled up version at 10 GHz was designed and measured. These results will also be presented.

  18. Design of the fundamental power coupler and photocathode inserts for the 112MHz superconducting electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Xin, T.; Ben-Zvi, I.; Belomestnykh, S.; Chang, X.; Rao, T.; Skaritka, J.; Wu, Q.; Wang, E.; Liang, X.

    2011-07-25

    A 112 MHz superconducting quarter-wave resonator electron gun will be used as the injector of the Coherent Electron Cooling (CEC) proof-of-principle experiment at BNL. Furthermore, this electron gun can be the testing cavity for various photocathodes. In this paper, we present the design of the cathode stalks and a Fundamental Power Coupler (FPC) designated to the future experiments. Two types of cathode stalks are discussed. Special shape of the stalk is applied in order to minimize the RF power loss. The location of cathode plane is also optimized to enable the extraction of low emittance beam. The coaxial waveguide structure FPC has the properties of tunable coupling factor and small interference to the electron beam output. The optimization of the coupling factor and the location of the FPC are discussed in detail. Based on the transmission line theory, we designed a half wavelength cathode stalk which significantly brings down the voltage drop between the cavity and the stalk from more than 5.6 kV to 0.1 kV. The transverse field distribution on cathode has been optimized by carefully choosing the position of cathode stalk inside the cavity. Moreover, in order to decrease the RF power loss, a variable diameter design of cathode stalk has been applied. Compared to the uniform shape of stalk, this design gives us much smaller power losses in important locations. Besides that, we also proposed a fundamental power coupler based on the designed beam parameters for the future proof-of-principle CEC experiment. This FPC should give a strong enough coupling which has the Q external range from 1.5e7 to 2.6e8.

  19. DESIGN AND CHARACTERIZATION OF THE POWER COUPLER LINE FOR HIE-ISOLDE HIGH BETA CAVITY

    CERN Document Server

    D'Elia, A

    2011-01-01

    The design parameters of the HIE-ISOLDE high beta superconducting (SC) cavity foresee to have a power dissipated on the cavity wall of 7W with a Q0=6.6·108 for an accelerating field of 6MV/m. The cavity will be fed via a moveable antenna that, in operating condition, is designed to reach a maximum overcoupled condition β=130 in order to get a bandwidth at the resonant frequency of ≈20Hz. A wide dynamic range (Qext ranging from 104 to 109) is requested in order to allow tests and conditioning both at room temperature and in superconducting operating mode. A “dust free” sliding mechanism has been integrated in the mechanical concept which will be presented below together the full e-m analysis of the coupler line.

  20. Next generation HOM-damping

    Science.gov (United States)

    Marhauser, Frank

    2017-06-01

    Research and development for superconducting radio-frequency cavities has made enormous progress over the last decades from the understanding of theoretical limitations to the industrial mass fabrication of cavities for large-scale particle accelerators. Key technologies remain hot topics due to continuously growing demands on cavity performance, particularly when in pursuit of high quality beams at higher beam currents or higher luminosities than currently achievable. This relates to higher order mode (HOM) damping requirements. Meeting the desired beam properties implies avoiding coupled multi-bunch or beam break-up instabilities depending on the machine and beam parameters that will set the acceptable cavity impedance thresholds. The use of cavity HOM-dampers is crucial to absorb the wakefields, comprised by all beam-induced cavity Eigenmodes, to beam-dynamically safe levels and to reduce the heat load at cryogenic temperature. Cavity damping concepts may vary, but are principally based on coaxial and waveguide couplers as well as beam line absorbers or any combination. Next generation energy recovery linacs and circular colliders call for cavities with strong HOM-damping that can exceed the state-of-the-art, while the operating mode efficiency shall not be significantly compromised concurrently. This imposes major challenges given the rather limited damping concepts. A detailed survey of established cavities is provided scrutinizing the achieved damping performance, shortcomings, and potential improvements. The scaling of the highest passband mode impedances is numerically evaluated in dependence on the number of cells for a single-cell up to a nine-cell cavity, which reveals the increased probability of trapped modes. This is followed by simulations for single-cell and five-cell cavities, which incorporate multiple damping schemes to assess the most efficient concepts. The usage and viability of on-cell dampers is elucidated for the single-cell cavity since it

  1. Design and analysis of O-S-C triple band wavelength division demultiplexer using cascaded MMI couplers

    Science.gov (United States)

    Chack, Devendra; Kumar, V.; Raghuwanshi, Sanjeev Kumar; Singh, Dev Prakash

    2017-01-01

    Compact triple O-S-C band wavelength demultiplexer, which consists of series cascaded multimode interference (MMI) couplers has been carried out in this paper. The MMI coupler has been used to drop the wavelengths of 1510 nm and 1550 nm at bar port while the wavelength 1300 nm into the cross port. Then another MMI coupler has been designed to separate the wavelength 1510 nminto one port and wavelength 1550 nm into another port. The triple wavelength demultiplexer function has been performed by choosing a suitable refractive index of the guiding region and geometrical parameters such as the width and length of MMI coupler. Numerical simulation with finite difference beam propagation method (BPM) has been utilized to design and optimize the operation of the proposed triple wavelength demultiplexer. The simulation results show that insertion losses of wavelength O, S and C, bands are 1.884 dB, 1.452 dB and 2.568 dB, respectively, with isolations for each output waveguide ranging from 10 dB to 28.72 dB. The 3-dB bandwidth of insertion loss for 1300 nm, 1510 nm and 1550 nm are 80 nm, 20 nm and 10 nm, respectively.

  2. Broadband terahertz fiber directional coupler

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Rasmussen, Henrik K.; Jepsen, Peter Uhd

    2010-01-01

    We present the design of a short broadband fiber directional coupler for terahertz (THz) radiation and demonstrate a 3 dB coupler with a bandwidth of 0:6 THz centered at 1:4 THz. The broadband coupling is achieved by mechanically downdoping the cores of a dual-core photonic crystal fiber by micro......We present the design of a short broadband fiber directional coupler for terahertz (THz) radiation and demonstrate a 3 dB coupler with a bandwidth of 0:6 THz centered at 1:4 THz. The broadband coupling is achieved by mechanically downdoping the cores of a dual-core photonic crystal fiber...

  3. Fabrication tolerant chalcogenide mid-infrared multimode interference coupler design with applications for Bracewell nulling interferometry.

    Science.gov (United States)

    Goldsmith, Harry-Dean Kenchington; Cvetojevic, Nick; Ireland, Michael; Madden, Stephen

    2017-02-20

    Understanding exoplanet formation and finding potentially habitable exoplanets is vital to an enhanced understanding of the universe. The use of nulling interferometry to strongly attenuate the central star's light provides the opportunity to see objects closer to the star than ever before. Given that exoplanets are usually warm, the 4 µm Mid-Infrared region is advantageous for such observations. The key performance parameters for a nulling interferometer are the extinction ratio it can attain and how well that is maintained across the operational bandwidth. Both parameters depend on the design and fabrication accuracy of the subcomponents and their wavelength dependence. Via detailed simulation it is shown in this paper that a planar chalcogenide photonic chip, consisting of three highly fabrication tolerant multimode interference couplers, can exceed an extinction ratio of 60 dB in double nulling operation and up to 40 dB for a single nulling operation across a wavelength window of 3.9 to 4.2 µm. This provides a beam combiner with sufficient performance, in theory, to image exoplanets.

  4. Design of a Directional Coupler based on UV-Induced LiNbO3 Waveguides

    Science.gov (United States)

    Ghosh, T.; Samanta, B.; Jana, P. C.; Ganguly, P.

    2017-08-01

    A semi-analytical technique, effective index-based matrix method (EIMM), has been applied to determine the coupling length of continuous wave UV-written directional coupler for different gaps between the waveguides as well as the pure bending loss and transition loss of S-curved waveguides estimated to optimize the transition length (L) and lateral offset (h). The refractive index profiles of the directional coupler were computed by solving the heat flow equation on the surface of LiNbO3 crystal, and used as input to EIMM.

  5. Spectral Collocation and FDTD Approaches for the Design of Focusung Grating Couplers

    DEFF Research Database (Denmark)

    Dridi, Kim; Dinesen, P.G.

    1999-01-01

    Theoretical and numerical investigations on sub-wavelength waveguide focusing grating couplers are presented. The analyses are based on two approaches, the spectral collocation method and the finite-difference time-domain method. The methods solve the full-vectorial time-domain Maxwell equations....

  6. Length minimization design considerations in photonic integrated circuits incorporating directional couplers

    Science.gov (United States)

    Boyd, Joseph T.; Radens, Carl J.; Kauffman, Michael T.

    1991-01-01

    Because directional couplers involve channel waveguides which are very close to one another, transition regions to regions where channel waveguides are widely separated are utilized. The total length of a directional coupler and transition regions can be minimized for a particular degree of field confinement. Calculations presented for LiNbO3-, GaAlAs-, and SiO2/Si-based optical channel waveguides demonstrate the presence of a minimum total length corresponding to a particular degree of field confinement. The overall length at the minimum is shown to be significantly lower than for other values of field confinement allowing single-mode operation. This implies that either more devices can be integrated on a substrate or that less material is needed for an integrated optical circuit.

  7. RF thermal and new cold part design studies on TTF-III input coupler for Project-X

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Shilun [Chinese Academy of Sciences (CAS), Beijing (China); Adolphsen, Chris E. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Li, Zenghai [SLAC National Accelerator Lab., Menlo Park, CA (United States); Solyak, Nikolay A. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Gonin, Ivan V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-05-15

    An RF power coupler is one of the key components in a superconducting (SC) linac. It provides RF power to the SC cavity and interconnects different temperature layers (1.8 K, 4.2 K, 70 K and 300 K). The TTF-III coupler is one of the most promising candidates for the High Energy (HE) linac of Project X, but it cannot meet the average power requirements because of the relatively high temperature rise on the warm inner conductor, so some design modifications will be required. In this paper, we describe our simulation studies on the copper coating thickness on the warm inner conductor with RRR values of 10 and 100. Our purpose is to rebalance the dynamic and static loads, and finally lower the temperature rise along the warm inner conductor. Additionally, to get stronger coupling, better power handling and less multipacting probability, one new cold part design was proposed using a 60 mm coaxial line; the corresponding multipacting simulation studies have also been investigated.

  8. Design and length optimization of an adiabatic coupler for on-chip vertical integration of rare-earth-doped double tungstate waveguide amplifiers

    NARCIS (Netherlands)

    Mu, Jinfeng; Sefünç, Mustafa; García Blanco, Sonia Maria

    2014-01-01

    The integration of rare-earth doped double tungstate waveguide amplifiers onto passive technology platforms enables the on-chip amplification of very high bit rate signals. In this work, a methodology for the optimized design of vertical adiabatic couplers between a passive Si3N4 waveguide and the

  9. Alternative Approaches for HOM Damped Cavities

    OpenAIRE

    Riemann, B.; Neumann, A.; Weis, T

    2012-01-01

    In this paper, we present two different ideas that may be useful for design and simulation of superconducting radio frequency cavities. To obtain longitudinal and transverse voltages resp. shunt impedances in cavities without rotational symmetry, one or two integration paths are often used to get an approximate difference relation for the transverse voltage of higher order modes HOMs . The presented approach uses a multipole decomposition that is valid in vicinity of the central a...

  10. Representability of Hom implies flatness

    Indian Academy of Sciences (India)

    ... A basic result of Grothendieck ([EGA], III 7.7.9) says that if F is flat over then hom ( E , F ) is representable for all E . We prove the converse of the above, in fact, we show that if is a relatively ample line bundle on over such that the functor hom ( L − n , F ) is representable for infinitely many positive integers , then F ...

  11. 49 CFR 179.14 - Coupler vertical restraint system.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Coupler vertical restraint system. 179.14 Section... TANK CARS General Design Requirements § 179.14 Coupler vertical restraint system. (a) Performance... not be equipped with couplers having this vertical restraint capability. (b) Test verification. Except...

  12. HOM identification by bead pulling in the Brookhaven ERL cavity

    CERN Document Server

    Hahn, H; Jain, Puneet; Johnson, Elliott C; Xu, Wencan

    2014-01-01

    Exploratory measurements of the Brookhaven Energy Recovery Linac (ERL) cavity at superconducting temperature produced a long list of high order modes (HOMs). The niobium 5-cell cavity is terminated at each end with HOM ferrite dampers that successfully reduce the Q-factors to levels required to avoid beam break up (BBU) instabilities. However, a number of un-damped resonances with Q≥106 were found at 4 K and their mode identification forms the focus of this paper. The approach taken here consists of bead pulling on a copper (Cu) replica of the ERL cavity with dampers involving various network analyzer measurements. Several different S21 transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, others between beam-position monitor probes in the beam tubes, and also between probes placed into the cells. The bead pull technique suitable for HOM identification with a metallic needle or dielectric bead is detailed. This paper presents the...

  13. Comparative Simulation Studies of Multipacting in Higher-Order-Mode Couplers of Superconducting RF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y. M. [Peking University, Beijing (China); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Liu, Kexin [Peking University, Beijing (China); Geng, Rongli [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-02-01

    Multipacting (MP) in higher-order-mode (HOM) couplers of the International Linear Collider (ILC) baseline cavity and the Continuous Electron Beam Accelerator Facility (CEBAF) 12 GeV upgrade cavity is studied by using the ACE3P suites, developed by the Advanced Computations Department at SLAC. For the ILC cavity HOM coupler, the simulation results show that resonant trajectories exist in three zones, corresponding to an accelerating gradient range of 0.6-1.6 MV/m, 21-34 MV/m, 32-35 MV/m, and > 40MV/m, respectively. For the CEBAF 12 GeV upgrade cavity HOM coupler, resonant trajectories exist in one zone, corresponding to an accelerating gradient range of 6-13 MV/m. Potential implications of these MP barriers are discussed in the context of future high energy pulsed as well as medium energy continuous wave (CW) accelerators based on superconducting radio frequency cavities. Frequency scaling of MP's predicted in HOM couplers of the ILC, CBEAF upgrade, SNS and FLASH third harmonic cavity is given and found to be in good agreement with the analytical result based on the parallel plate model.

  14. Modules Over Color Hom-Poisson Algebras

    OpenAIRE

    Bakayoko, Ibrahima

    2014-01-01

    In this paper we introduce color Hom-Poisson algebras and show that every color Hom-associative algebra has a non-commutative Hom-Poisson algebra structure in which the Hom-Poisson bracket is the commutator bracket. Then we show that color Poisson algebras (respectively morphism of color Poisson algebras) turn to color Hom-Poisson algebras (respectively morphism of Color Hom-Poisson algebras) by twisting the color Poisson structure. Next we prove that modules over color Hom–associative algebr...

  15. The LINAC4 Power Coupler

    CERN Document Server

    Gerigk, F; Montesinos, E; Riffaud, B; Ugena Tirado, P; Wegner, R

    2011-01-01

    Linac4 is employing three types of accelerating structures after the RFQ: a Drift Tube Linac (DTL), a Cell- Coupled DTL (CCDTL), and a Pi-Mode Structure (PIMS) to accelerate the beam up to 160 MeV at 352.2MHz. The structures are designed for a peak power of approximately 1 MW per power coupler, which is transported via rectangular waveguides from the klystron gallery to the RF cavities. The coupler itself consists of two parts: a ceramic window, which separates the cavity vacuum from the air in the waveguides, and a Tuner-adjustablewaveguide Coupler (TaCo), which couples the RF power through an iris to the cavity. In the frame of the Linac4 R&D both devices have been significantly improvedwith respect to their commonly used design. On the coupler side, the waveguide short circuit with its matched length has been replaced by a fixedlength /4 short circuit. The RF matching is done by a simple piston tuner, which allows a quick matching to different cavity quality factors. In the window part, which usually c...

  16. A Tandem Coupler for Terahertz Integrated Circuits

    Science.gov (United States)

    Reck, Theodore J.; Deal, William; Chattopadhyay, Goutam

    2013-01-01

    A coplanar waveguide 3 dB quadrature coupler operating from 500 to 700 GHz is designed, fabricated and measured. On-wafer measurements demonstrate an amplitude balance of +/-2 dB and phase balance of +/-20 deg.

  17. Fabrication of LD-3 Polymer Directional Couplers

    National Research Council Canada - National Science Library

    Chen, Ray T

    1998-01-01

    .... LD-3 polymer directional couplers arc designed and fabricated to operate at 1.3 microns. Waveguide propagation losses, device characterization, demonstration of cross coupling and packaged device pictures are presented in this final report.

  18. Design of second order grating couplers to detect the angle and polarization of the laser beam

    Science.gov (United States)

    Saha, Tapas Kumar; Lu, Mingyu; Zhao, Deyin; Ma, Zhenqiang; Zhou, Weidong

    2012-03-01

    On-chip laser beam tracking finds innumerable applications. Popularly adopted quadrant photodiodes can only detect laser beam's angle variation up to 0.2° reliably. In this paper, a novel angle detector is designed based on grating coupling. It consists of a grating layer on top of a silicon-on-insulator slab waveguide. The incident light is coupled into guided modes within the waveguide via the grating layer, and then, the incident light's angle can be determined by reading the outputs of light detectors within the waveguide. Performance of the laser angle detector in this paper is demonstrated by full-wave finite-difference-time-domain simulations. Numerical results show that, the detectable angle range can be adjusted by several design parameters and can reach [-4°, 4°]. The device structure in this paper can be straightforwardly extended to two-dimensional photonic crystal configurations.

  19. Design of a hybrid silicon-plasmonic co-propagating coupler operating close to coherent perfect absorption

    Energy Technology Data Exchange (ETDEWEB)

    Zanotto, Simone; Melloni, Andrea [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2016-04-28

    By hybrid integration of plasmonic and dielectric waveguide concepts, it is shown that nearly perfect coherent absorption can be achieved in a co-propagating coupler geometry. First, the operating principle of the proposed device is detailed in the context of a more general 2 × 2 lossy coupler formalism. Then, it is shown how to tune the device in a wide region of possible working points, its broadband operation, and the tolerance to fabrication uncertainties. Finally, a complete picture of the electromagnetic modes inside the hybrid structure is analyzed, shining light onto the potentials which the proposed device holds in view of classical and quantum signal processing, nonlinear optics, polarization control, and sensing.

  20. First Considerations Concerning an Optimized Cavity Design for the Main Linac of BERLinPro

    Energy Technology Data Exchange (ETDEWEB)

    B. Riemann, T. Weis, W. Anders, J. Knobloch, A. Neumann, H.-W. Glock, C. Potratz, U. van Rienen, F. Marhauser

    2011-09-01

    The Berlin Energy Recovery Linac Project (BERLinPro) is designed to develop and demonstrate CW linac technology and expertise required to drive next-generation Energy Recovery Linacs. Strongly HOM-damped multicell 1.3 GHz cavities are required for the main linac. The optimization of the cavities presented here is primarily based on the CEBAF 1.5 GHz 5-cell high-current cavity design, including HOM waveguide couplers. The cavity was scaled to 1.3 GHz and extended to 7 cells. Modifications to the end group design have also been studied. An effort was also made to reduce the ratio Epk/Eacc while still permitting HOMs to propagate.

  1. Meta-$\\mathcal{PT}$ Symmetry in Asymmetric Directional Couplers

    CERN Document Server

    Ma, Chicheng; Litchinitser, Natalia M

    2015-01-01

    Despite the benefits that directional coupler based parity-time symmetric systems may offer to the field of integrated optics, the realization of such couplers relies on rather strict design constraints on the waveguide parameters. Here, we investigate directional couplers built of asymmetric waveguides that do not fulfill parity-time symmetry. Nevertheless, we demonstrate that for properly designed parameters, at least one mode of such couplers shows a behavior similar to the one observed in parity-symmetric systems. We find an analytical condition relating gain and loss that enables such a behavior. Moreover, if the individual waveguides composing the asymmetric coupler are designed such that the propagation constants of their modes are identical, the behavior of both super-modes supported by the coupler resembles that of the parity-time symmetric systems.

  2. Optical fiber couplers for precision spaceborne metrology.

    Science.gov (United States)

    Killow, Christian J; Fitzsimons, Ewan D; Perreur-Lloyd, Michael; Robertson, David I; Ward, Henry; Bogenstahl, Johanna

    2016-04-01

    We describe the optical and mechanical design, construction philosophy, and testing of a pair of matched, spaceflight-qualified fiber couplers. The couplers were developed for the LISA Pathfinder mission but are relevant for other applications-both on ground and in space-where a robust fiber coupler with well-controlled beam parameters and stable beam pointing is required. This particular implementation of the design called for two couplers providing collimated beams with individual waist sizes and positions. The target values were a 522 μm waist 145 mm after the collimating lens for one coupler and a virtual 520 μm waist 194 mm before the collimating lens for the second coupler. Values of (542±4)  μm at (142±19) mm and (500±8)  μm at (-275±8)  mm were achieved, fully meeting the mission requirements. To control spurious noise effects in the interferometer, the optical system design also specified tight limits on relative beam curvature at an intended interference point. With nominal curvatures at this location of ∼2.35  m, the matching between the outputs of the two fiber couplers was measured to be λ/33 peak-valley over the central 1 mm of the beams. Results showing pointing stability of 3 μrad/°C over a 50°C range are presented. The vibration, shock, and thermal vacuum environmental testing conditions to which a pair of qualification fiber couplers were subjected-without change in performance-are listed.

  3. BNL 56 MHz HOM Damper Prototype Fabrication at JLab

    Energy Technology Data Exchange (ETDEWEB)

    Huque, Naeem A. [Jefferson Lab., Newport News, VA (United States); Daly, Edward F. [Jefferson Lab., Newport News, VA (United States); Clemens, William A. [Jefferson Lab., Newport News, VA (United States); McIntyre, Gary T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wu, Qiong [Brookhaven National Lab. (BNL), Upton, NY (United States); Seberg, Scott [Brookhaven National Lab. (BNL), Upton, NY (United States); Bellavia, Steve [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-09-01

    A prototype Higher-Order Mode (HOM) Damper was fabricated at JLab for the Relativistic Heavy-Ion Collider's (RHIC) 56 MHz cavity at Brookhaven National Laboratory (BNL). Primarily constructed from high RRR Niobium and Sapphire, the coaxial damper presented significant challenges in electron-beam welding (EBW), brazing and machining via acid etching. The results of the prototype operation brought about changes in the damper design, due to overheating braze alloys and possible multi-pacting. Five production HOM dampers are currently being fabricated at JLab. This paper outlines the challenges faced in the fabrication process, and the solutions put in place.

  4. BNL 56 MHz HOM damper prototype fabrication at JLAB

    Energy Technology Data Exchange (ETDEWEB)

    Huque, N.; McIntyre, G.; Daly, E. F.; Clemens, W.; Wu, Q.; Seberg, S.; Bellavia, S.

    2015-05-03

    A prototype Higher-Order Mode (HOM) Damper was fabricated at JLab for the Relativistic Heavy-Ion Collider’s (RHIC) 56 MHz cavity at Brookhaven National Laboratory (BNL). Primarily constructed from high RRR Niobium and Sapphire, the coaxial damper presented significant challenges in electron-beam welding (EBW), brazing and machining via acid etching. The results of the prototype operation brought about changes in the damper design, due to overheating braze alloys and possible multi-pacting. Five production HOM dampers are currently being fabricated at JLab. This paper outlines the challenges faced in the fabrication process, and the solutions put in place.

  5. Birefringent coupler for integrated optics.

    Science.gov (United States)

    Brandt, G B

    1974-06-01

    An optical coupler has been developed whereby a birefringent prism or substrate is utilized to couple light into thin film optical waveguides. The coupler is designed so that the incident light, polarized as an extraordinary wave, passes through the birefringent material at such an angle that the index of refraction in the input medium is higher than that of the waveguide. In addition, the orientation of the birefringent material is chosen so that the reflected waves within the waveguide are incident on the input medium at such an angle that the medium index of refraction appears lower than that of the waveguide. In this way, the light is trapped within the waveguide and, when the light is incident at the appropriate angle, this light propagates in the waveguide as a single mode. Coupling takes place over the whole area common to the waveguide and input medium; thus, neither a sharp edge nor a trapped evanescent region are required to prevent the light coupled into the waveguide from leaking back into the coupling prism. The absence of a boundary makes it practical to couple wide beams of light into planar guides. Couplers made of calcite have been used to couple TM He-Ne laser light into multimode waveguides formed of liquids and optical cement.

  6. High magnetic fields in couplers of x-band acceleratingstructures

    CERN Document Server

    Dolgashev, V A

    2003-01-01

    Recent high power tests of x-band accelerating structures at SLAC have shown that Coupler models were matched with an automated procedure that uses the commercial To reduce the high magnetic fields new couplers were designed. These couplers and typical results for couplers with sharp and rounded irises are discussed in code HFSS. This matching procedure is based on calculation of reflection from have 3 mm radius waveguide-to-coupler-cell iris and maximum magnetic field below is consistent with a model of pulsed heating due to high magnetic fields. The magnetic fields, 3D electrodynamics models of the couplers were built and matched. matching, the magnetic and electric fields in the couplers were calculated for typical observed damage is located in the region of high magnetic fields. To calculate these on sharp (approx 80 micron radius) edges of the waveguide-to-coupler-cell irises. For operation parameters. Highest magnetic fields on the order of 1 MA/m were found some input couplers, electric fields on these...

  7. Acoustic Coupler for the Acquisition of Coronary Artery Murmurs

    DEFF Research Database (Denmark)

    Zimmermann, Niels Henrik; Schmidt, Samuel; Hansen, John

    in a broad frequency range. The coupler was designed to have a high cut off frequency at 1.0 kHz, while the low frequency behavior was determined by the properties of the microphone, electronic circuits and inadvertent leakages in the acoustical coupling. The performance of the acoustical coupler...

  8. Mountain-Shaped Coupler for Ultra Wideband Applications

    Directory of Open Access Journals (Sweden)

    D.N.A. Zaidel

    2013-09-01

    Full Text Available This paper demonstrates a novel mountain-shaped design for a compact 3-dB coupler operating at ultra-wideband (UWB frequencies from 3.1GHz to 10.6 GHz. The proposed design was accomplished using multilayer technology in which the structure is formed by three layers of conductors interleaved by a layer of substrate between each conductor layer. Simulation was carried out using CST Microwave Studio; the result was then compared with results from rectangular and star-shaped couplers that implemented the same technique. The results obtained show that the proposed new coupler has better performance compared to both rectangular and star-shaped coupler designs in terms of return loss, isolation, and phase difference. The coupler was fabricated and measured; the measurement results satisfactorily agree with the simulation results.

  9. Integrated optical XY coupler

    Science.gov (United States)

    Vawter, G. Allen; Hadley, G. Ronald

    1997-01-01

    An integrated optical XY coupler having two converging input waveguide arms meeting in a central section and a central output waveguide arm and two diverging flanking output waveguide arms emanating from the central section. In-phase light from the input arms constructively interfers in the central section to produce a single mode output in the central output arm with the rest of the light being collected in the flanking output arms. Crosstalk between devices on a substrate is minimized by this collection of the out-of-phase light by the flanking output arms of the XY coupler.

  10. Thermal Calculations Of Input Coupler For Erl Injector

    CERN Document Server

    Sobenin, N P; Bogdanovich, B Yu; Kaminsky, V I; Krasnov, A A; Lalayan, M V; Veshcherevich, V G; Zavadtsev, A A; Zavadtsev, D A

    2004-01-01

    The thermal calculation results of input coupler for ERL injector cavities are presented [1]. A twin coaxial coupler of TTF-3 type was chosen for 2×75 kW RF power transfer. TTF-3 coupler was intended for high pulse and not high average power transmission, so there were revisings proposed in its design. New coupler configuration provides thermal leakage not more than 0.2 W at temperature 2.0K, 2 W at the temperature 4,0K and 50 W at temperature 80K. Construction revising was made at "cold" and "warm" bellows. In particularly, bellows separating was proposed to install additional heat sink. Coupler configuration with "warm" window of choke type was examined. It provides mechanical uncoupling of input waveguide and ceramic insulator. Electrodynamics simulations were carried out by MicroWaveStudio and HFSS codes, thermal analysis was maid using ANSYS.

  11. Design of the 1.5 MW, 30-96 MHz ultra-wideband 3 dB high power hybrid coupler for Ion Cyclotron Resonance Frequency (ICRF) heating in fusion grade reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Rana Pratap, E-mail: ranayadav97@gmail.com; Kumar, Sunil; Kulkarni, S. V. [Thapar University, Patiala, Punjab 147004, India and Institute for Plasma Research, Gandhinagar 382428 (India)

    2016-01-15

    Design and developmental procedure of strip-line based 1.5 MW, 30-96 MHz, ultra-wideband high power 3 dB hybrid coupler has been presented and its applicability in ion cyclotron resonance heating (ICRH) in tokamak is discussed. For the high power handling capability, spacing between conductors and ground need to very high. Hence other structural parameters like strip-width, strip thickness coupling gap, and junction also become large which can be gone upto optimum limit where various constrains like fabrication tolerance, discontinuities, and excitation of higher TE and TM modes become prominent and significantly deteriorates the desired parameters of the coupled lines system. In designed hybrid coupler, two 8.34 dB coupled lines are connected in tandem to get desired coupling of 3 dB and air is used as dielectric. The spacing between ground and conductors are taken as 0.164 m for 1.5 MW power handling capability. To have the desired spacing, each of 8.34 dB segments are designed with inner dimension of 3.6 × 1.0 × 40 cm where constraints have been significantly realized, compensated, and applied in designing of 1.5 MW hybrid coupler and presented in paper.

  12. Cryogenic testing of the 2.1 GHz five-cell superconducting RF cavity with a photonic band gap coupler cell

    Energy Technology Data Exchange (ETDEWEB)

    Arsenyev, Sergey A., E-mail: arsenyev@mit.edu; Temkin, Richard J. [Massachusetts Institute of Technology, 77 Mass. Ave., Cambridge, Massachusetts 02139 (United States); Haynes, W. Brian; Shchegolkov, Dmitry Yu.; Simakov, Evgenya I.; Tajima, Tsuyoshi [Los Alamos National Laboratory, PO Box 1663, Los Alamos, New Mexico 87545 (United States); Boulware, Chase H.; Grimm, Terrence L.; Rogacki, Adam R. [Niowave, Inc., 1012 North Walnut Street, Lansing, Michigan 48906 (United States)

    2016-05-30

    We present results from cryogenic tests of the multi-cell superconducting radio frequency (SRF) cavity with a photonic band gap (PBG) coupler cell. Achieving high average beam currents is particularly desirable for future light sources and particle colliders based on SRF energy-recovery-linacs (ERLs). Beam current in ERLs is limited by the beam break-up instability, caused by parasitic higher order modes (HOMs) interacting with the beam in accelerating cavities. A PBG cell incorporated in an accelerating cavity can reduce the negative effect of HOMs by providing a frequency selective damping mechanism, thus allowing significantly higher beam currents. The multi-cell cavity was designed and fabricated of niobium. Two cryogenic (vertical) tests were conducted. The high unloaded Q-factor was demonstrated at a temperature of 4.2 K at accelerating gradients up to 3 MV/m. The measured value of the unloaded Q-factor was 1.55 × 10{sup 8}, in agreement with prediction.

  13. Microwave coupler and method

    Science.gov (United States)

    Holcombe, C. E.

    1984-11-01

    The present invention is directed to a microwave coupler for enhancing the heating or metallurgical treatment of materials within a cold-wall, rapidly heated cavity as provided by a microwave furnace. The coupling material of the present invention is an alpha-rhombohedral-boron-derivative-structure material such as boron carbide or boron silicide which can be appropriately positioned as a susceptor within the furnace to heat other material or be in powder particulate form so that composites and structures of boron carbide such as cutting tools, grinding wheels and the like can be rapidly and efficiently formed within microwave furnaces.

  14. Vacuum fiber-fiber coupler

    Science.gov (United States)

    Heinrici, Axel; Bjelajac, Goran; Jonkers, Jeroen; Jakobs, Stefan; Olschok, Simon; Reisgen, Uwe

    2017-02-01

    Research and development carried out by the ISF Welding and Joining Institute of RWTH Aachen University has proven that combining high power laser and low vacuum atmosphere provides a welding performance and quality, which is comparable to electron beam welding. The developed welding machines are still using a beam forming which takes place outside the vacuum and the focusing laser beam has to be introduced to the vacuum via a suitable window. This inflexible design spoils much of the flexibility of modern laser welding. With the target to bring a compact, lightweight flying optics with flexible laser transport fibers into vacuum chambers, a high power fiber-fiber coupler has been adapted by II-VI HIGHYAG that includes a reliable vacuum interface. The vacuum-fiber-fiber coupler (V-FFC) is tested with up to 16 kW sustained laser power and the design is flexible in terms of a wide variety of laser fiber plug systems and vacuum flanges. All that is needed to implement the V-FFC towards an existing or planned vacuum chamber is an aperture of at least 100 mm (4 inch) diameter with any type of vacuum or pressure flange. The V-FFC has a state-of-the-art safety interface which allows for fast fiber breakage detection for both fibers (as supported by fibers) by electric wire breakage and short circuit detection. Moreover, the System also provides connectors for cooling and electric signals for the laser beam optics inside the vacuum. The V-FFC has all necessary adjustment options for coupling the laser radiation to the receiving fiber.

  15. Substrate Integrated Waveguide (SIW Coupler on Green Material Substrate for Internet of Things (IoT Applications

    Directory of Open Access Journals (Sweden)

    Khalid Nurehansafwanah

    2017-01-01

    Full Text Available This paper shows designed coupler on paper-substrate with Substrate Integrated Waveguide (SIW techniques. Types of paper-substrate that used are photographic paper. The rectangular coupler is presented with Substrate Integrated Waveguide (SIW which metallic via on paper-substrate. The structures of the coupler are designed and analysed using Computer Simulation Tools (CST Studio Suite 2014 Software. This designed coupler operating within frequency of 3.8-5 GHz. The paper-based substrates are permits the implementation of green materials (Eco-friendly technology. The design of the coupler and its simulated results are reported in this paper.

  16. Substrate integrated waveguide (SIW 3 dB coupler for K-Band applications

    Directory of Open Access Journals (Sweden)

    Khalid Nurehansafwanah

    2017-01-01

    Full Text Available This paper presented a designed coupler by using Rogers RO4003C with thickness (h 0.508 mm and relative permittivity (εr 3.55. The four port network coupler operates in K-band (18-27 GHz and design by using substrate integrated waveguide (SIW method. The reflection coefficient and isolation coefficient of propose Substrate Integrated Waveguide (SIW coupler is below than -10 dB. Meanwhile the coupler requirements are phase shift 90° between coupled port and output. SIW are high performance broadband interconnects with excellent immunity to electromagnetic interference and suitable for use in microwave and communication electronics, as well as increase bandwidth systems. The designs of coupler are investigated using CST Microwave Studio simulation tool. This proposed couplers are varied from parameters that cover the frequency range (21 -24 GHz and better performance of scattering (S-parameter.

  17. Design of a 4 Rod Crab Cavity Cryomodule System for HL-LHC

    CERN Document Server

    Burt, G; Wright, L; Peterson, T J; Jones, T; McIntosh, P A; Templeton, N; Pattalwar, S; Wheelhouse, A E

    2013-01-01

    The LHC requires compact SRF crab cavities for the HL-LHC and 3 potential solutions are under consideration. One option is to develop a 4 rod cavity utilising for quarter wave rods to maintain a dipole field. The cavity design has been developed including power and LOM/HOM couplers have been developed, as well as a conceptual design of a complete cryomodule system including ancillaries and this is presented. The cryomodule is designed to allow easy access during testing and uses a novel support system and contains the opposing beamline section to fit inside the LHC envelope.

  18. 70-nm-bandwidth achromatic waveguide coupler.

    Science.gov (United States)

    Mendes, S B; Li, L; Burke, J J; Lee, J E; Saavedra, S S

    1995-09-20

    We report a general approach to the design of broadband waveguide couplers. A double-parallel grating assembly is used to cancel the first chromatic order, and a proper choice of prism glass and base angle is made to compensate for the second chromatic order. The technique was applied to a Corning glass 7059 waveguide, and a spectral bandwidth of 70 nm was measured by the use of two complementary procedures.

  19. Ultrahigh-efficiency apodized grating coupler using fully etched photonic crystals

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ou, Haiyan; Peucheret, Christophe

    2013-01-01

    We present an efficient method to design apodized grating couplers with Gaussian output profiles for efficient coupling between standard single mode fibers and silicon chips. An apodized grating coupler using fully etched photonic crystal holes on the silicon-on-insulator platform is designed...

  20. An evaluation of high voltage cable-coupler performance for underground mine power systems

    Energy Technology Data Exchange (ETDEWEB)

    Bise, C.; Morley, L.A.

    1982-07-01

    High voltage cable couplers are convenient and widely used accessories in modern coal-mine power distribution systems for aiding in the extension and retraction of power-feeder cables throughout a mine. Coupler design has tried to keep pace with the industry's desire to move to higher distribution levels, but the increase in recorded failures of 15 kV-class couplers, which serve the distribution levels of 12.47 kV and above, have inhibited this transition. The problems associated with high-voltage cable couplers are analyzed. Manufacturing, testing, and mounting practices are reviewed. A discussion of a coupler's operating environment is also included. On the basis of the aforementioned conditions, a testing standard is developed and various coupler designs are subjected to its requirements. An analysis of the test results is provided. Although new couplers can satisfy the performance requirements of the cables to which they are mounted, partial discharge appears to be the failure mechanism of concern. The effects of partial discharge are magnified where voids, either in the insulation, cable termination, or potting compound, occur. In this regard, it is shown that the quality of installation of a coupler onto cable is quite critical. By slightly altering the mounting procedure satisfactory partial-discharge readings are produced on a test coupler.

  1. A Three-Cell Superconducting Deflecting Cavity Design for the ALS at LBNL

    CERN Document Server

    Shi, Jiaru; Chen Huai Bi; Li, Derun; Zheng, Shuxin

    2005-01-01

    Deflecting RF cavities can be used to generate sub-pico-second x-rays by creating correlations between longitudinal and transverse phase space of electron bunches in radiation devices. Up to 2-MV defecting voltage at 1.5-GHz is required for 1.9-GeV electron beam at the Advanced Light Source (ALS) at LBNL. We present a conceptual design for a 1.5-GHz three-cell superconducting RF cavity and its coupler. The cavity geometry and deflecting shunt impedance are optimized using MAFIA code. The cavity impedance from lower and higher order modes (LOM and HOM) are computed. Possible schemes for damping most harmful LOM and HOM modes are discussed and simulated.

  2. Predicted stresses and strains in fused biconical taper couplers subjected to tension.

    Science.gov (United States)

    Suhir, E

    1993-06-20

    In fused biconical taper (FBT) couplers, the cores of the fibers are positioned close to each other. In order to bring the cores of the fibers in close proximity, the cladding in the fused midportion of the coupler has to be made thin. At the same time the coupler must be sufficiently strong, both on a short- and a long-time scale, and must be able to withstand appreciable axial deformations. These can be caused by the thermal contraction mismatch of the coupler with its substrate or can be due to a deliberate prestressing of the coupler structure in order to improve its dynamic stability. In this study an easy-to-apply analytical stress model is developed for the evaluation of stresses and strains in FBT couplers from the expected or measured total elongation. In the analysis the nonprismaticity of the coupler structure as well as the nonlinear behavior of the material was considered. The numerical example has been carried out for a coupler that is intended for undersea applications. The results obtained can be used in the stress-strain analyses and physical design of light-wave FBT couplers.

  3. Broadband polymer microstructured THz fiber coupler with downdoped cores

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Rasmussen, Henrik K.; Bang, Ole

    2010-01-01

    We demonstrate a broadband THz directional coupler based on a dual core photonic crystal fiber (PCF) design with mechanically down-doped core regions. For a center frequency of 1.3 THz we demonstrate a bandwidth of 0.65 THz.......We demonstrate a broadband THz directional coupler based on a dual core photonic crystal fiber (PCF) design with mechanically down-doped core regions. For a center frequency of 1.3 THz we demonstrate a bandwidth of 0.65 THz....

  4. Broadband optical directional full couplers based on Blackman function

    Science.gov (United States)

    Chen, Chi-Feng; Ku, Yun-Sheng

    2008-11-01

    A mismatched optical coupler with waveguide weighted by the Blackman function is numerically investigated in the demand of short-length, C+L-band, low crosstalk, and process tolerance. Utilizing the full factorial design, the structure parameters of coupling waveguide are obtained by beam propagation method. In the condition of crosstalk of -33.5 dB, the mismatched optical coupler with proper selected waveguide structure parameters is found to have a coupling length of 2.80 mm in the transmission wavelength ranges of C+L-band (1.53~1.61 μm). Obviously, the selection and design of waveguide structure are very important to satisfy the qualities of a mismatched optical coupler for the demand of short-length, bandwidth, and low-crosstalk.

  5. Dealing with Multipacting in Fundamental Power Couplers for SRF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Mircea Stirbet

    2005-03-19

    Multipacting events are well known and bothersome discharge phenomena specific to vacuum and RF exposed surfaces. Left uncontrolled, these events could affect normal machine operation, limiting performance or inducing irreversible damage of critical components such as ceramic windows. Numerical simulations have been developed and their predictions fit fairly well with real multipacting events in coaxial lines or waveguide-type fundamental power couplers. Controlling multipacting must be considered from the design stage, as well as during manufacture of subassemblies or preparation of the coupler for cavity assembly. All fundamental power couplers must be conditioned using a high power RF source, and during this process, restricting multipacting by adequate instrumentation should be considered. After RF conditioning, during beam acceleration, control of multipacting is achieved with field perturbation methods. This paper summarizes our experience in dealing with multipacting in CW or pulsed fundamental power couplers (LEP, LHC, SNS and RIA) for SRF cavities. The SNS fundamental power coupler is used as an example for controlling multipacting during high power RF conditioning.

  6. Grating coupler on single-crystal lithium niobate thin film

    Science.gov (United States)

    Chen, Zhihua; Wang, Yiwen; Jiang, Yunpeng; Kong, Ruirui; Hu, Hui

    2017-10-01

    The grating coupler on single-crystal lithium niobate thin film (lithium niobate on insulator, LNOI) was designed. A bottom reflector was added in the LNOI material to improve the coupling efficiency. The grating structure was optimized by FDTD method. The material parameters such as layer thickness of lithium niobate thin film, SiO2 thickness were discussed with respect to the coupling efficiency, and the tolerances of grating period, etch depth, groove width and fiber position were also studied systematically. The simulated maximum coupling efficiency from a grating coupler with (without) bottom reflector to a single-mode fiber is about 78% (40%) in z-cut LNOI for TE polarization.

  7. A classification of low dimensional multiplicative Hom-Lie superalgebras

    Directory of Open Access Journals (Sweden)

    Wang Chunyue

    2016-01-01

    Full Text Available We study a twisted generalization of Lie superalgebras, called Hom-Lie superalgebras. It is obtained by twisting the graded Jacobi identity by an even linear map. We give a complete classification of the complex multiplicative Hom-Lie superalgebras of low dimensions.

  8. Fabrication Of Fiber-Optic Waveguide Coupler

    Science.gov (United States)

    Goss, Willis; Nelson, Mark D.; Mclauchlan, John M.

    1989-01-01

    Technique for making four-port, single-mode fiber-optic waveguide couplers requires no critically-precise fabrication operations or open-loop processes. Waveguide couplers analogous to beam-splitter prisms. Essential in many applications that require coherent separation or combination of two waves; for example, for interferometric purposes. Components of optical waveguide coupler held by paraffin on microscope slide while remaining cladding of two optical fibers fused together by arc welding.

  9. Strip-slot direct mode coupler.

    Science.gov (United States)

    Han, Kyunghun; Kim, Sangsik; Wirth, Justin; Teng, Min; Xuan, Yi; Niu, Ben; Qi, Minghao

    2016-03-21

    We present a direct strip-slot waveguide mode coupler without any auxiliary structures. Contrary to popular belief, an apparent mode mismatch between strip and slot waveguide does not deteriorate conversion efficiency. Separated electric and magnetic field distributions in a slot waveguide lead to highly efficient modal coupling in the direct strip-slot coupler and result in high conversion efficiency. Accurate experimental characterization shows that the direct strip-slot waveguide mode coupler is capable of up to 96% conversion efficiency with a broad bandwidth. Being simplest and of high efficiency, the direct strip-slot waveguide mode coupler can encourage potential applications of slot waveguides.

  10. Design of high gradient, high repetition rate damped C -band rf structures

    Science.gov (United States)

    Alesini, David; Bellaveglia, Marco; Bini, Simone; Gallo, Alessandro; Lollo, Valerio; Pellegrino, Luigi; Piersanti, Luca; Cardelli, Fabio; Migliorati, Mauro; Mostacci, Andrea; Palumbo, Luigi; Tocci, Simone; Ficcadenti, Luca; Pettinacci, Valerio

    2017-03-01

    The gamma beam system of the European Extreme Light Infrastructure-Nuclear Physics project foresees the use of a multibunch train colliding with a high intensity recirculated laser pulse. The linac energy booster is composed of 12 traveling wave C -band structures, 1.8 m long with a field phase advance per cell of 2 π /3 and a repetition rate of 100 Hz. Because of the multibunch operation, the structures have been designed with a dipole higher order mode (HOM) damping system to avoid beam breakup (BBU). They are quasiconstant gradient structures with symmetric input couplers and a very effective damping of the HOMs in each cell based on silicon carbide (SiC) rf absorbers coupled to each cell through waveguides. An optimization of the electromagnetic and mechanical design has been done to simplify the fabrication and to reduce the cost of the structures. In the paper, after a review of the beam dynamics issues related to the BBU effects, we discuss the electromagnetic and thermomechanic design criteria of the structures. We also illustrate the criteria to compensate the beam loading and the rf measurements that show the effectiveness of the HOM damping.

  11. Design of high gradient, high repetition rate damped C-band rf structures

    Directory of Open Access Journals (Sweden)

    David Alesini

    2017-03-01

    Full Text Available The gamma beam system of the European Extreme Light Infrastructure–Nuclear Physics project foresees the use of a multibunch train colliding with a high intensity recirculated laser pulse. The linac energy booster is composed of 12 traveling wave C-band structures, 1.8 m long with a field phase advance per cell of 2π/3 and a repetition rate of 100 Hz. Because of the multibunch operation, the structures have been designed with a dipole higher order mode (HOM damping system to avoid beam breakup (BBU. They are quasiconstant gradient structures with symmetric input couplers and a very effective damping of the HOMs in each cell based on silicon carbide (SiC rf absorbers coupled to each cell through waveguides. An optimization of the electromagnetic and mechanical design has been done to simplify the fabrication and to reduce the cost of the structures. In the paper, after a review of the beam dynamics issues related to the BBU effects, we discuss the electromagnetic and thermomechanic design criteria of the structures. We also illustrate the criteria to compensate the beam loading and the rf measurements that show the effectiveness of the HOM damping.

  12. Beam Pipe HOM Absorber for 750 MHz RF Cavity Systems

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland; Neubauer, Michael

    2014-10-29

    This joint project of Muons, Inc., Cornell University and SLAC was supported by a Phase I and Phase II grant monitored by the SBIR Office of Science of the DOE. Beam line HOM absorbers are a critical part of future linear colliders. The use of lossy materials at cryogenic temperatures has been incorporated in several systems. The design in beam pipes requires cylinders of lossy material mechanically confined in such a way as to absorb the microwave energy from the higher-order modes and remove the heat generated in the lossy material. Furthermore, the potential for charge build-up on the surface of the lossy material requires the conductivity of the material to remain consistent from room temperature to cryogenic temperatures. In this program a mechanical design was developed that solved several design constraints: a) fitting into the existing Cornell load vacuum component, b) allowing the use of different material compositions, c) a thermal design that relied upon the compression of the lossy ceramic material without adding stress. Coating experiments were performed that indicated the design constraints needed to fully implement this approach for solving the charge build-up problem inherent in using lossy ceramics. In addition, the ACE3P program, used to calculate the performance of lossy cylinders in beam pipes in general, was supported by this project. Code development and documentation to allow for the more wide spread use of the program was a direct result of this project was well.

  13. A Novel Multimode Waveguide Coupler for Accurate Power Measurement of Traveling Wave Tube Harmonic Frequencies

    Science.gov (United States)

    Wintucky, Edwin G.; Simons, Rainee N.

    2014-01-01

    This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler fabricated from two dissimilar waveguides is capable of isolating the power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT). In addition to accurate power measurements at harmonic frequencies, a potential application of the MDC is in the design of a beacon source for atmospheric propagation studies at millimeter-wave frequencies.

  14. Cancellation of RF Coupler-Induced Emittance Due to Astigmatism

    Energy Technology Data Exchange (ETDEWEB)

    Dowell, David H.; /SLAC

    2016-12-11

    It is well-known that the electron beam quality required for applications such as FEL’s and ultra-fast electron diffraction can be degraded by the asymmetric fields introduced by the RF couplers of superconducting linacs. This effect is especially troublesome in the injector where the low energy beam from the gun is captured into the first high gradient accelerator section. Unfortunately modifying the established cavity design is expensive and time consuming, especially considering that only one or two sections are needed for an injector. Instead, it is important to analyze the coupler fields to understand their characteristics and help find less costly solutions for their cancellation and mitigation. This paper finds the RF coupler-induced emittance for short bunches is mostly due to the transverse spatial sloping or tilt of the field, rather than the field’s time-dependence. It is shown that the distorting effects of the coupler can be canceled with a static (DC) quadrupole lens rotated about the z-axis.

  15. HOM Consideration of 704 MHz and 2.1 GHz Cavities for LEReC Linac

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Binping [RIKEN BNL; Belomestnykh, Sergey [SUNY, Stony Brook; Ben-Zvi, Ilan [RIKEN BNL; Blaskiewicz, Michael [RIKEN BNL; Brennan, Joseph [RIKEN BNL; Brutus, Jean Clifford [RIKEN BNL; Fedotov, Alexei [RIKEN BNL; Hahn, Harald [RIKEN BNL; McIntyre, Gary [RIKEN BNL; Pai, Chien [RIKEN BNL; Smith, Kevin [RIKEN BNL; Tuozzolo, Joseph [RIKEN BNL; Veshcherevich, Vadim [Cornell U., CLASSE; Wu, Qiong [RIKEN BNL; Xin, Tianmu [RIKEN BNL; Xu, Wencan [RIKEN BNL; Zaltsman, Alex [RIKEN BNL

    2016-06-01

    To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, the Low Energy RHIC electron Cooler (LEReC) is currently under development at BNL. The Linac of LEReC is designed to deliver 2 MV to 5 MV electron beam, with rms dp/p less than 5·10⁻⁴. The HOM in this Linac is carefully studied to ensure this specification.

  16. Simulation of TunneLadder Traveling-Wave Tube Input/Output Coupler Characteristics Using MAFIA

    Science.gov (United States)

    Kory, Carol L.; Qureshi, A. Haq

    1996-01-01

    RF input/output coupler characteristics for the TunneLadder traveling-wave tube have been calculated using the three-dimensional computer code, MAFIA and compared to experimental data with good agreement. Theory behind coupling of the TunneLadder interaction circuit to input and output waveguides is presented and VSWR data is calculated for variations on principal coupler dimensions to provide insight into manufacturing tolerances necessary for acceptable performance. Accuracy of results using MAFIA demonstrates how experimental hardware testing of three-dimensional coupler designs can be reduced.

  17. Monolithic fiber coupler for high power diode laser bars: results of prototype

    Science.gov (United States)

    Mitra, T.; Bagschik, K.; Kalkusinki, A.

    2017-02-01

    A novel micro optical element is introduced, allowing coupling of light from several emitters of a laser diode bar into an optical fiber at high brightness. The monolithic fiber coupler is designed with individual segments for each emitter of the laser diode bar, providing two refractive surfaces for each emitter. By means of the monolithic fiber coupler, very cost effective fiber coupled laser diode modules based on bars are feasible. Consequently, approaches based on laser diodes bars can also compete with single emitter solutions for pumping application. Further applications of laser modules with monolithic fiber couplers may also be for direct material processing or as components in projection and illumination systems.

  18. HOM Dampers or not in Superconducting RF Proton Linacs

    CERN Document Server

    Tückmantel, Joachim

    2009-01-01

    Circular machines are plagued by Coupled Bunch Instabilities, driven by impedance peaks, irrespectively of their frequency relation to machine lines; hence all cavity Higher Order Modes are possible drivers. This is the fundamental reason that all superconducting RF cavities in circular machines are equipped with HOM dampers. This raises the question if HOM damping would not be imperative also in high current proton linacs where a mechanism akin to CBI might exist. To clarify this question we have simulated the longitudinal bunched beam dynamics in linacs, allowing bunch-to-bunch variations in time-of-arrival. Simulations were executed for a generic proton linac with properties close to SNS or the planned SPL at CERN. It was found that for monopole HOMs with high Qext large beam scatter or even beam loss cannot be excluded. Therefore omitting HOM dampers on superconducting RF cavities in high current proton linacs, even pulsed ones, is a very risky decision.

  19. HOM Dampers or not in SUPERCONDUCTING RF Proton Linacs

    CERN Document Server

    Tückmantel, Joachim

    2009-01-01

    Circular machines are plagued by Coupled Bunch Instabilities, driven by impedance peaks, irrespectively of their frequency relation to machine lines; hence all cavity Higher Order Modes are possible drivers. This is the fundamental reason that all superconducting RF cavities in circular machines are equipped with HOM dampers. This raises the question if HOM damping would not be imperative also in high current proton linacs where a mechanism akin to CBI might exist. To clarify this question we have simulated the longitudinal bunched beam dynamics in linacs, allowing bunch-to-bunch variations in time-of-arrival. Simulations were executed for a generic proton linac with properties close to SNS or the planned SPL at CERN. It was found that for monopole HOMs with high Qext large beam scatter or even beam loss cannot be excluded. Therefore omitting HOM dampers on superconducting RF cavities in high current proton linacs, even pulsed ones, is a very risky decision.

  20. Yetter-Drinfeld modules for Hom-bialgebras

    Energy Technology Data Exchange (ETDEWEB)

    Makhlouf, Abdenacer, E-mail: Abdenacer.Makhlouf@uha.fr [Université de Haute Alsace, Laboratoire de Mathématiques, Informatique et Applications, 4, rue des frères Lumière, F-68093 Mulhouse (France); Panaite, Florin, E-mail: Florin.Panaite@imar.ro [Institute of Mathematics of the Romanian Academy, PO-Box 1-764, RO-014700 Bucharest (Romania)

    2014-01-15

    The aim of this paper is to define and study Yetter-Drinfeld modules over Hom-bialgebras, a generalized version of bialgebras obtained by modifying the algebra and coalgebra structures by a homomorphism. Yetter-Drinfeld modules over a Hom-bialgebra with bijective structure map provide solutions of the Hom-Yang-Baxter equation. The category H/HYD of Yetter-Drinfeld modules with bijective structure maps over a Hom-bialgebra H with bijective structure map can be organized, in two different ways, as a quasi-braided pre-tensor category. If H is quasitriangular (respectively, coquasitriangular) the first (respectively, second) quasi-braided pre-tensor category H/HYD contains, as a quasi-braided pre-tensor subcategory, the category of modules (respectively, comodules) with bijective structure maps over H.

  1. Simulation of HOM Leakage in the PEP-II Bellows

    CERN Document Server

    Ng, Cho-Kuen; Ge, Lixin; Langton, Jay; Lee, Lie-Quan; Novokhatski, Alexander

    2005-01-01

    An important factor that limits the PEP-II from operating at higher currents is higher-order-mode (HOM) heating of the bellows. One source of HOM heating is the formation of trapped modes at the bellows as a result of geometry variation in the vacuum chamber, for example, the masking near the central vertex chamber. Another source comes from HOMs generated upstream that leak through the gaps between the bellows fingers. Modeling the fine details of the bellows and the surrounding geometry requires the resolution and accuracy only possible with a large number of mesh points on an unstructured grid. We use the parallel finite element eigensolver Omega3P for trapped mode calculations, and the S-matrix solver S3P for transmission analysis. The damping of the HOMs by the use of absorbers inside the bellows will be investigated.

  2. Modal-insensitive biconical-taper couplers.

    Science.gov (United States)

    Tremblay, Y; Kawasaki, B S; Bilodeau, F

    1982-10-01

    A method for fabricating optical-fiber fused biconical-taper couplers that have coupling ratios insensitive to the modal distribution of light in the input fiber arms is demonstrated. Comparison measurements of the performance of these couplers and those made by the previous technique are presented and discussed.

  3. Acoustic coupler for acquisition of coronary artery murmurs

    DEFF Research Database (Denmark)

    Zimmermann, Niels Henrik; Schmidt, Samuel; Hansen, John

    2011-01-01

    of the coupler, while the low frequency behavior was determined by the properties of the microphone, electronic circuits and inadvertent leakages in the acoustical coupling. The requirement for the microphone and pr-amplifier was a low inherent noise level. The setup was used for collection of heart sounds...... frequency range of interest related to murmurs is part of the purpose of the study, one of the goals of the design was to achieve a high signal to noise ratio in a broad frequency range. The high cut off frequency of the coupler is determined by the acoustic impedance of the chest and the design...... in a clinical trial including 463 patients referred for elective coronary angiography. The preliminary results show, that it was possible to record heart sound in the diastolic period with a sound pressure level approximately 30 dB above the noise floor of the microphone and recording system in the frequency...

  4. All-fiber mode selective couplers for mode-division-multiplexed optical transmission

    Science.gov (United States)

    Chang, Sun Hyok; Kim, Kwangjoon; Lee, Joon Ki

    2017-01-01

    All-fiber mode selective coupler (MSC) is comprised of a few mode fiber (FMF) and a single mode fiber (SMF), coupling the LP01 mode of the SMF to a specific higher-order mode (HOM) of the FMF. In order to achieve high coupling ratio and low insertion loss, phase-matching condition between the LP01 mode of SMF arm and the HOM of FMF arm should be satisfied. A polished-type MSC is made by getting their cores into intimate contact. Prism coupling with a polished coupler block can measure the effective refractive index of the mode accurately. We propose and demonstrate three kinds of allfiber mode multiplexer that is composed of consecutive MSCs. 4-mode multiplexer can multiplex 4 modes of LP01, LP11, LP21, and LP02 by cascading LP11, LP21, and LP02 MSCs. It is used for MDM transmission of three modes with 120 Gb/s DP-QPSK signals. In order to enhance the signal transmission performance by receiving degenerate LP modes simultaneously, a mode multiplexer to utilize two-fold degenerate LP11 modes is proposed. It is composed of two consecutive LP11 MSCs that allows the multiplexing of LP01 mode and two orthogonal LP11 modes. We demonstrates WDM transmission of 30 wavelength channels with 33.3 GHz spacing, each carrying 3 modes, over 560 km of FMF. 6- mode multiplexer can multiplex 6 modes of LP01, LP11a, LP11b, LP21a, LP21b, LP02 modes. We demonstrated WDM-MDM transmission with the all-fiber 6-mode multiplexer. In this paper, the manufacturing method and the recent advancements of the all-fiber mode multiplexer based on the MSCs are reviewed. Long-distance mode division multiplexing (MDM) optical signal transmissions with the all-fiber mode multiplexer are experimentally demonstrated.

  5. Miniature mechanical transfer optical coupler

    Science.gov (United States)

    Abel, Philip [Overland Park, KS; Watterson, Carl [Kansas City, MO

    2011-02-15

    A miniature mechanical transfer (MT) optical coupler ("MMTOC") for optically connecting a first plurality of optical fibers with at least one other plurality of optical fibers. The MMTOC may comprise a beam splitting element, a plurality of collimating lenses, and a plurality of alignment elements. The MMTOC may optically couple a first plurality of fibers disposed in a plurality of ferrules of a first MT connector with a second plurality of fibers disposed in a plurality of ferrules of a second MT connector and a third plurality of fibers disposed in a plurality of ferrules of a third MT connector. The beam splitting element may allow a portion of each beam of light from the first plurality of fibers to pass through to the second plurality of fibers and simultaneously reflect another portion of each beam of light from the first plurality of fibers to the third plurality of fibers.

  6. Couplers for non-locality swapping

    Energy Technology Data Exchange (ETDEWEB)

    Skrzypczyk, Paul; Brunner, Nicolas [H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)], E-mail: paul.skrzypczyk@bristol.ac.uk, E-mail: n.brunner@bristol.ac.uk

    2009-07-15

    Studying generalized non-signaling theories brings insight into the foundations of quantum mechanics. Here we focus on a dynamical process in such general theories, namely non-locality swapping, the analogue of quantum entanglement swapping. In order to implement such a protocol, one needs to define a coupler, which performs the equivalent of quantum joint measurements on generalized 'box-like' states. Establishing a connection to Bell inequalities, we define consistent couplers for theories containing an arbitrary amount of non-locality, which leads us to introduce the concepts of perfect and minimal couplers. Remarkably, Tsirelson's bound for quantum non-locality naturally appears in our study.

  7. A Four-Decade Bandwidth Hybrid Coupler

    CERN Document Server

    Belleman, J M

    1999-01-01

    A hybrid coupler is a reciprocal radio-frequency building block with four ports. Signal power applied to any port is equally divided between the two adjacent ports, while the remaining port receives none. Hybrid couplers find many uses in RF circuitry. Our specific application is the elaboration of sum and difference of the signals produced by an electrostatic position pick-up in a particle accelerator. Hybrids qualified as 'Wide-Band' commonly span two octaves of frequency, and the best ultra-wideband devices cover about three decades. The hybrid coupler described here has a useful response from 40kHz tosome 400MHz.

  8. Distributed Bragg Coupler for Optical All-dielectric Electron Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.; Tantawi, S.G.; Ruth, R.D.; /SLAC

    2005-09-30

    A Bragg waveguide consisting of multiple dielectric layers with alternating index of refraction provides confinement of a synchronous speed-of-light mode with extremely low loss. There are three requirements in designing input coupler for a Bragg electron accelerator: side-coupling, selective mode excitation, and high coupling efficiency. We present a side coupling scheme using a Bragg-grating-assisted input coupler to address these three requirements. Side coupling is achieved by a second order Bragg grating with a period on the order of an optical wavelength. The phase matching condition results in resonance coupling thus providing selective mode excitation capability. We demonstrate a non-uniform distributed grating structure generating an outgoing beam with a Gaussian profile, therefore, increasing the coupling efficiency.

  9. Rotating optical coupler for signal transmission

    Science.gov (United States)

    Ivie, C. V.

    1977-01-01

    Optical coupler using Dove prism assembly to form stationary image of rotating object, transmits data across rotating interface without sliprings or other mechanical contacts. Device can handle many high-bit-rate data channels.

  10. Couplers for Non-Locality Swapping

    OpenAIRE

    Skrzypczyk, Paul; Brunner, Nicolas

    2008-01-01

    Studying generalized non-local theories brings insight to the foundations of quantum mechanics. Here we focus on non-locality swapping, the analogue of quantum entanglement swapping. In order to implement such a protocol, one needs a coupler that performs the equivalent of quantum joint measurements on generalized `box-like' states. Establishing a connection to Bell inequalities, we define consistent couplers for theories containing an arbitrary amount of non-locality, which leads us to intro...

  11. Fast optical switching in nonlinear prism couplers.

    Science.gov (United States)

    Fick, J; Vitrant, G

    1995-07-01

    The excitation process of short optical pulses in waveguides by use of prism couplers is studied with a fully dynamic model. A good coupling efficiency is obtained even for short pulses. Fast nonlinear behavior such as power limiting and optical switching is predicted with a response time much shorter than the buildup time of the waveguide coupler. This new result is due to the group-velocity matching between the guided and the pump fields.

  12. Geometric optimisation of an accurate cosine correcting optic fibre coupler for solar spectral measurement

    Science.gov (United States)

    Cahuantzi, Roberto; Buckley, Alastair

    2017-09-01

    Making accurate and reliable measurements of solar irradiance is important for understanding performance in the photovoltaic energy sector. In this paper, we present design details and performance of a number of fibre optic couplers for use in irradiance measurement systems employing remote light sensors applicable for either spectrally resolved or broadband measurement. The angular and spectral characteristics of different coupler designs are characterised and compared with existing state-of-the-art commercial technology. The new coupler designs are fabricated from polytetrafluorethylene (PTFE) rods and operate through forward scattering of incident sunlight on the front surfaces of the structure into an optic fibre located in a cavity to the rear of the structure. The PTFE couplers exhibit up to 4.8% variation in scattered transmission intensity between 425 nm and 700 nm and show minimal specular reflection, making the designs accurate and reliable over the visible region. Through careful geometric optimization near perfect cosine dependence on the angular response of the coupler can be achieved. The PTFE designs represent a significant improvement over the state of the art with less than 0.01% error compared with ideal cosine response for angles of incidence up to 50°.

  13. Monopole HOMs Dumping in the LCLS-II 1.3 GHz Structure

    Energy Technology Data Exchange (ETDEWEB)

    Lunin, Andrei [Fermilab; Khabiboulline, Timergali [Fermilab; Solyak, Nikolay [Fermilab

    2017-05-01

    Developing an upgrade of Linac Coherent Light Source (LCLS-II) is currently underway. The central part of LCLS-II is a continuous wave superconducting RF (CW SRF) electron linac. High order modes (HOMs) excited in SRF structures by passing beam may deteriorate beam quality and affect beam stability. In this paper we report the simulation results of monopole High Order Modes (HOM) spectrum in the 1.3 GHz accelerating structure. Optimum parameters of the HOM feedthrough are suggested for minimizing RF losses on the HOM antenna tip and for preserving an efficiency of monopole HOMs damping simultaneously.

  14. Ultra-low coupling loss fully-etched apodized grating coupler with bonded metal mirror

    DEFF Research Database (Denmark)

    Ding, Yunhong; Peucheret, Christophe; Ou, Haiyan

    2014-01-01

    A fully etched apodized grating coupler with bonded metal mirror is designed and demonstrated on the silicon-on-insulator platform, showing an ultra-low coupling loss of only 1.25 dB with 3 dB bandwidth of 69 nm.......A fully etched apodized grating coupler with bonded metal mirror is designed and demonstrated on the silicon-on-insulator platform, showing an ultra-low coupling loss of only 1.25 dB with 3 dB bandwidth of 69 nm....

  15. Multiplexing of adjacent vortex modes with the forked grating coupler

    Science.gov (United States)

    Nadovich, Christopher T.; Kosciolek, Derek J.; Crouse, David T.; Jemison, William D.

    2017-08-01

    For vortex fiber multiplexing to reach practical commercial viability, simple silicon photonic interfaces with vortex fiber will be required. These interfaces must support multiplexing. Toward this goal, an efficient singlefed multimode Forked Grating Coupler (FGC) for coupling two different optical vortex OAM charges to or from the TE0 and TE1 rectangular waveguide modes has been developed. A simple, apodized device implemented with e-beam lithography and a conventional dual-etch processing on SOI wafer exhibits low crosstalk and reasonable mode match. Advanced designs using this concept are expected to further improve performance.

  16. Candida albicans Hom6 is a homoserine dehydrogenase involved in protein synthesis and cell adhesion

    Directory of Open Access Journals (Sweden)

    Pei-Wen Tsai

    2017-12-01

    Full Text Available Background/Purpose: Candida albicans is a common fungal pathogen in humans. In healthy individuals, C. albicans represents a harmless commensal organism, but infections can be life threatening in immunocompromised patients. The complete genome sequence of C. albicans is extremely useful for identifying genes that may be potential drug targets and important for pathogenic virulence. However, there are still many uncharacterized genes in the Candida genome database. In this study, we investigated C. albicans Hom6, the functions of which remain undetermined experimentally. Methods: HOM6-deleted and HOM6-reintegrated mutant strains were constructed. The mutant strains were compared with wild-type in their growth in various media and enzyme activity. Effects of HOM6 deletion on translation were further investigated by cell susceptibility to hygromycin B or cycloheximide, as well as by polysome profiling, and cell adhesion to polystyrene was also determined. Results: C. albicans Hom6 exhibits homoserine dehydrogenase activity and is involved in the biosynthesis of methionine and threonine. HOM6 deletion caused translational arrest in cells grown under amino acid starvation conditions. Additionally, Hom6 protein was found in both cytosolic and cell-wall fractions of cultured cells. Furthermore, HOM6 deletion reduced C. albicans cell adhesion to polystyrene, which is a common plastic used in many medical devices. Conclusion: Given that there is no Hom6 homologue in mammalian cells, our results provided an important foundation for future development of new antifungal drugs. Keywords: Candida albicans, cell adhesion, Hom6, homoserine dehydrogenase, protein synthesis

  17. Ternary q-Virasoro-Witt Hom-Nambu-Lie algebras

    Energy Technology Data Exchange (ETDEWEB)

    Ammar, F [Faculte des Sciences, Universite de Sfax, BP 1171, 3000 Sfax (Tunisia); Makhlouf, A [Laboratoire de Mathematiques, Informatique et Applications, Universite de Haute Alsace, 4, rue des Freres Lumiere F-68093 Mulhouse (France); Silvestrov, S, E-mail: Faouzi.Ammar@rnn.fss.t, E-mail: Abdenacer.Makhlouf@uha.f, E-mail: sergei.silvestrov@math.lth.s [Centre for Mathematical Sciences, Lund University, Box 118, SE-221 00 Lund (Sweden)

    2010-07-02

    In this paper we construct ternary q-Virasoro-Witt algebras which q-deform the ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos using su(1, 1) enveloping algebra techniques. The ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos depend on a parameter and are not Nambu-Lie algebras for all but finitely many values of this parameter. For the parameter values for which the ternary Virasoro-Witt algebras are Nambu-Lie, the corresponding ternary q-Virasoro-Witt algebras constructed in this paper are also Hom-Nambu-Lie because they are obtained from the ternary Nambu-Lie algebras using the composition method. For other parameter values this composition method does not yield a Hom-Nambu-Lie algebra structure for q-Virasoro-Witt algebras. We show however, using a different construction, that the ternary Virasoro-Witt algebras of Curtright, Fairlie and Zachos, as well as the general ternary q-Virasoro-Witt algebras we construct, carry a structure of the ternary Hom-Nambu-Lie algebra for all values of the involved parameters.

  18. Waveguide couplers for ferroelectric optical resonators

    OpenAIRE

    Grudinin, Ivan S.; Kozhanov, A.; Yu, N.

    2014-01-01

    We report a study of using the same material to fabricate a whispering gallery mode resonator and a coupler. Coupling to high Q whispering gallery modes of the lithium niobate resonator is demonstrated by means of the titanium-doped waveguide. The waveguide coupling approach opens possibilities for simpler and wider practical usage of whispering gallery mode resonators and their integration into optical devices.

  19. High-performance cryogenic fractal 180° hybrid power divider with integrated directional coupler

    Science.gov (United States)

    Ladu, Adelaide; Montisci, Giorgio; Valente, Giuseppe; Navarrini, Alessandro; Marongiu, Pasqualino; Pisanu, Tonino; Mazzarella, Giuseppe

    2017-06-01

    A 180° hybrid and a directional coupler to be employed in the P-band cryogenic receiver of the Sardinia Radio Telescope are proposed in this work. An in-depth study of the issues related to the use of microwave components for cryogenic radio astronomy receivers is carried out to select the best suited technology and configuration. As a result, a planar fractal 180° hybrid configuration available in the literature has been optimized aiming to increase the operating bandwidth in order to comply with the design specifications of the application at hand. A coupled line directional coupler with weak coupling and high isolation, used to calibrate the receiver chain, is cascaded to the 180° hybrid and realized in the same layout. The final device, consisting of the 180° hybrid and the directional coupler, has been manufactured and tested at the cryogenic temperature of 20 K, showing a good agreement between experimental results and predicted performance.

  20. Femtosecond laser fabrication of birefringent directional couplers as polarization beam splitters in fused silica.

    Science.gov (United States)

    Fernandes, Luís A; Grenier, Jason R; Herman, Peter R; Aitchison, J Stewart; Marques, Paulo V S

    2011-06-20

    Integrated polarization beam splitters based on birefringent directional couplers are demonstrated. The devices are fabricated in bulk fused silica glass by femtosecond laser writing (300 fs, 150 nJ at 500 kHz, 522 nm). The birefringence was measured from the spectral splitting of the Bragg grating resonances associated with the vertically and horizontally polarized modes. Polarization splitting directional couplers were designed and demonstrated with 0.5 dB/cm propagation losses and -19 dB and -24 dB extinction ratios for the polarization splitting.

  1. D10.8.1: Test and operation of the couplers preparation procedure

    CERN Document Server

    Napoly, O

    2013-01-01

    As far as the Task 10.8.1 is concerned the activity was to define the process of the automatic couplers cleaning, to have a full review of the different phases and to establish the necessary hardware components. After this the design of the machine and of its components has been realised. This has provided the faisability study and the costing of the automatic couplers cleaning machine. Hereafter we give a short summary of the main apects of the two phases: the definition of the automatic cleaning procedure and the study of the washing machine.

  2. Structural Analysis of Taper-Threaded Rebar Couplers

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Seok Jae [Univ. of Ulsan, Ulsan (Korea, Republic of); Kwon, Hyuk Mo; Seo, Sang Hwan [Sammi Precision Co. Ltd., Ulsan (Korea, Republic of)

    2014-05-15

    A number of rebar couplers were developed by the leading companies. The information about the products is available from the company website. However, the theory on the taper-threaded coupler is not available. In this paper, the mechanics of the taper-thread was developed to understand the effect of the tightening torque. Structural analysis of our own newly developed rebar coupler was done to improve the strength of the coupler. The taper-threaded rebar coupler was analyzed. The tightening of the rebar into the coupler developed a circumferential stress in the coupler. The circumferential stress depends on the coefficient of friction as well as the tightening torque. The circumferential stress is less than the allowable stress 20 kgf/mm{sup 2} of the material for the coefficient of friction greater than 0.1. The tightening of the rebar into the coupler and the subsequent tensioning was simulated using CATIA. Linear elastic analysis considering contact was done. The tightening of the taper-threaded rebar developed a uniform stress distribution in both standard coupler and position coupler. On the other hand, the tightening of the nut in the axial direction developed a non-uniform stress distribution. Similarly the tensioning also developed a non-uniform stress distribution.

  3. Reconfigurable/tunable dual band/dual mode ferrite composite right/left-handed CPW coupled-line coupler

    Science.gov (United States)

    Abdalla, M. A.; Hu, Z.

    2017-09-01

    This paper presents the design, modeling and experimental verification of a novel reconfigurable/tunable dual band/dual mode ferrite composite right/left handed CPW coupled-line coupler. The composite right/left handed configuration has been realized by loading coupled CPW transmission lines with series inter-digital capacitors and shunt segment inductors. The coupler performance has been verified using the equivalent circuit model, electromagnetic full wave simulations and experimental measurements. The coupler operates on dual mode in that it has dual bands of operation with two different propagation mechanisms. The first band has only a reciprocal backward coupling whereas the second band has only nonreciprocal through propagation. The non-reciprocity isolation in the second band is better than average of 15 dB. Compared to conventional single band single mode coupled line coupler of length = 0.25 λg, the proposed novel dual band dual mode coupler length is almost the same (0.265 λg) at 4.5 GHz. Furthermore, the dual mode/dual band coupler can have tunable functionality.

  4. Broadband high-efficiency zero-order surface grating coupler for the near- and mid-infrared wavelength ranges

    Science.gov (United States)

    Sánchez-Postigo, Alejandro; Wangüemert-Pérez, J. Gonzalo; Luque-González, José Manuel; Molina-Fernández, Íñigo; Cheben, Pavel; Alonso-Ramos, Carlos A.; Halir, Robert; Schmid, Jens H.; Ortega-Moñux, Alejandro

    2017-05-01

    Efficient coupling of light from a chip into an optical fiber is a major issue in silicon photonics, as the dimensions of high-index-contrast photonic integrated waveguides are much smaller than conventional fiber diameters. Surface grating couplers address the coupling problem by radiating the optical power from a waveguide through the surface of the chip to the optical fiber, or vice versa. However, since the grating radiation angle substantially varies with the wavelength, conventional surface grating couplers cannot offer high coupling efficiency and broad bandwidth simultaneously. To overcome this limitation, for the near-infrared band we have recently proposed SOI-based zero-order grating couplers, which, making use of a subwavelength-engineered waveguide and a high-index prism, suppress the explicit dependence between the radiation angle and the wavelength, achieving a 1-dB bandwidth of 126 nm at λ = 1.55 μm. However, in the near-infrared, the bandwidth enhancement of zero-order grating couplers is limited by the effective index wavelength dispersion of the grating. In the mid-infrared spectral region, the waveguide dispersion is lower, alleviating the bandwidth limitation. Here we demonstrate numerically our zero-order grating coupler concept in the mid-infrared at λ = 3.8 μm. Several couplers for the silicon-on-insulator and the germanium-on-silicon nitride platforms are designed and compared, with subdecibel coupling efficiencies and 1-dB bandwidths up to 680 nm.

  5. Optical Nonreciprocity in Asymmetric Optomechanical Couplers

    Science.gov (United States)

    Wang, Zheqi; Shi, Lei; Liu, Yi; Xu, Xinbiao; Zhang, Xinliang

    2015-03-01

    We propose an all-optical integrated nonreciprocal device on the optomechanical platform with a large nonreciprocal bandwidth and low operating power. The device is based on an asymmetric silicon coupler consisting of two branches. One of them is a conventional strip waveguide fixed on the substrate, and the other is a freestanding nanostring suspended above a groove in the substrate. When light is launched into the coupler, the optical gradient force between the freestanding nanostring and the underlying substrate leads to the deflection of the nanostring, and finally results in destruction of the initial phase-matching condition between the two branches. The suspended branch would achieve distinct deflections when light is incident from different ports. The simulation results show a nonreciprocal bandwidth of 13.1 nm with operating power of 390 μW. With the advantages of simple structure, low power consumption and large operating bandwidth, our work provides a promising solution for on-chip passive nonreciprocal device.

  6. Large-scale characterization of silicon nitride-based evanescent couplers at 532nm wavelength

    Science.gov (United States)

    Claes, Tom; Jansen, Roelof; Neutens, Pieter; Du Bois, Bert; Helin, Philippe; Severi, Simone; Van Dorpe, Pol; Deshpande, Paru; Rottenberg, Xavier

    2014-05-01

    Recently, the photonics community has a renewed attention for silicon nitride.1-3 When deposited at temperatures below 650K with plasma-enhanced chemical vapor deposition (PECVD),4 it enables photonic circuits fabricated on-top of standard complementary metaloxidesemiconductor (CMOS) electronics. Silicon nitride is moreover transparent to wavelengths that are visible to the human eye and detectable with available silicon detectors, thus offering a photonics platform for a range of applications that is not accessible with the popular silicon-on-insulator platform. However, first-time-right design of large-scale circuits for demanding specifications requires reliable models of the basic photonic building blocks, like evanescent couplers (Figure 1), components that couple power between multiple waveguides. While these models typically exist for the silicon-on-insulator platform, they still lack maturity for the emerging silicon nitride platform. Therefore, we meticulously studied silicon nitride-based evanescent couplers fabricated in our 200mm-wafer facility. We produced the structures in a silicon nitride film deposited with low-temperature PECVD, and patterned it using optical lithography at a wavelength of 193nm and reactive ion etching. We measured the performance of as much as 250 different designs at 532nm wavelength, a central wavelength in the visible range for which laser sources are widespread. For each design, we measured the progressive transmission of up-to 10 cascaded identical couplers (Figure 2(a)), yielding very accurate figures for the coupling factor (Figure 2(b)). This paper presents the trends extracted from this vast data set (Figure 3), and elaborates on the impact of the couplers bend radius and gap on its coupling factors (Figure 4 and Figure 5). We think that the large- scale characterization of evanescent couplers presented in this paper, in excellent agreement with the simulated performance of the devices, forms the basis for a component

  7. Coupling of earphones to human ear and to coupler

    Science.gov (United States)

    Ciric, Dejan; Hammershoi, Dorte

    2004-05-01

    The use of a standardized acoustical coupler should enable a calibration of audiometric earphones which ensures that the thresholds determined in the audiometry will be independent of the earphone type. This requires that the coupler approximates the average human ear closely. Nevertheless, the differences among earphones as well as between human ears and the coupler affect the results of audiometric measurements inducing uncertainty. The influence of these differences is examined by investigating the coupling of different earphones to human ears and to the standardized coupler. This is done by measurement of the transfer functions from input voltage of the earphone terminals to the entrance of the ear canal in two situations: (1) open, and (2) blocked. Similar measurements were carried out with the coupler, but since the ``ear-canal entrance'' is not well-defined for the coupler, the mentioned measurements were done at different depths in the coupler. The earphone's coupling to (i) human ears and to (ii) the coupler, described in terms of the pressure division at the entrance of the ear canal, were compared. The results indicate that the coupling to the human ear and the coupling to the standardized coupler differ.

  8. Analysis of a fused biconical single-mode star coupler.

    Science.gov (United States)

    Eisenmann, M; Weidel, E

    1989-08-01

    A new type of star coupler for single-mode optical fibers is proposed. The geometrical configuration of the coupler is intended to be a tapered cylindrical ring structure. A numerical analysis yields the evolution of the light distribution along the coupling region and the spectral characteristics of the coupler. For a star coupler with 8 x 8 ports and a length of 14 mm a spectral width of 90 nm was calculated, if an additional loss of 0.5 dB is tolerated.

  9. Multimode Directional Coupler for Utilization of Harmonic Frequencies from TWTAs

    Science.gov (United States)

    Simmons, Rainee N.; Wintucky, Edwin G.

    2013-01-01

    A novel waveguide multimode directional coupler (MDC) intended for the measurement and potential utilization of the second and higher order harmonic frequencies from high-power traveling wave tube amplifiers (TWTAs) has been successfully designed, fabricated, and tested. The design is based on the characteristic multiple propagation modes of the electrical and magnetic field components of electromagnetic waves in a rectangular waveguide. The purpose was to create a rugged, easily constructed, more efficient waveguide- based MDC for extraction and exploitation of the second harmonic signal from the RF output of high-power TWTs used for space communications. The application would be a satellitebased beacon source needed for Qband and V/W-band atmospheric propagation studies. The MDC could function as a CW narrow-band source or as a wideband source for study of atmospheric group delay effects on highdata- rate links. The MDC is fabricated from two sections of waveguide - a primary one for the fundamental frequency and a secondary waveguide for the second harmonic - that are joined together such that the second harmonic higher order modes are selectively coupled via precision- machined slots for propagation in the secondary waveguide. In the TWTA output waveguide port, both the fundamental and the second harmonic signals are present. These signals propagate in the output waveguide as the dominant and higher order modes, respectively. By including an appropriate mode selective waveguide directional coupler, such as the MDC presented here at the output of the TWTA, the power at the second harmonic can be sampled and amplified to the power level needed for atmospheric propagation studies. The important conclusions from the preliminary test results for the multimode directional coupler are: (1) the second harmonic (Ka-band) can be measured and effectively separated from the fundamental (Ku-band) with no coupling of the latter, (2) power losses in the fundamental frequency

  10. Mode multiplexer based on integrated horizontal and vertical polymer waveguide couplers.

    Science.gov (United States)

    Dong, Jiangli; Chiang, Kin Seng; Jin, Wei

    2015-07-01

    We demonstrate a mode demultiplexer with two cascaded few-mode polymer waveguide directional couplers fabricated on the same substrate along the horizontal and vertical directions, respectively. The three waveguides that form the two couplers have the same core size. The horizontal and vertical couplers are designed to provide complete power transfer for the LP(11a) and LP(11b) modes, with the LP(01) mode staying in the central core that incorporates a biconical taper to suppress any remaining LP(11) modes. A typical fabricated demultiplexer, which is 18.5 mm long, shows a coupling ratio higher than ∼96% in the wavelength range of 1530-1570 nm for both couplers. The device shows negligible crosstalk to the LP(01)-mode channel, while the crosstalks to the LP(11)-mode channels are lower than -15.6 and -13.4  dB for the TE and TM polarizations, respectively. The device can be considered polarization insensitive. The propagation losses for the three modes are about 2.0  dB/cm. This device could find applications in mode-division-multiplexing systems.

  11. Microstructure analysis in the coupling region of fiber coupler with a novel electrical micro-heater

    Science.gov (United States)

    Shuai, Cijun; Gao, Chengde; Nie, Yi; Hu, Huanlong; Peng, Shuping

    2011-12-01

    Fused-tapered fiber coupler is widely used in optical-fiber communication, optical-fiber sensor and optical signal processing. Its optical performance is mainly determined by the glass properties in the coupling region. In this study, the effect of fused biconical taper (FBT) process on glass microstructure of fiber coupler was investigated by testing the microstructure of the cross-section of coupling region. The fiber coupler is fabricated with a novel home-designed electrical heater. Our experimental results show that the boundary between fiber core and fiber cladding become vague or indistinct after FBT under transmission electron microscopy (TEM) and Ge 2+ in fiber core diffuses into fiber cladding. Crystallizations are observed in coupling region under scanning electron microscope (SEM) and microscopic infrared (IR), and the micro crystallizations become smaller with the drawing speed increasing. The wave number of fiberglass increases after FBT and it is in proportion to the drawing speed. The analysis of the microstructure in the coupling region explored the mechanism of the improvement in the performance of fiber couplers which can be used for the guidance of fabrication process.

  12. Cpl6: The New Extensible, High-Performance Parallel Coupler forthe Community Climate System Model

    Energy Technology Data Exchange (ETDEWEB)

    Craig, Anthony P.; Jacob, Robert L.; Kauffman, Brain; Bettge,Tom; Larson, Jay; Ong, Everest; Ding, Chris; He, Yun

    2005-03-24

    Coupled climate models are large, multiphysics applications designed to simulate the Earth's climate and predict the response of the climate to any changes in the forcing or boundary conditions. The Community Climate System Model (CCSM) is a widely used state-of-art climate model that has released several versions to the climate community over the past ten years. Like many climate models, CCSM employs a coupler, a functional unit that coordinates the exchange of data between parts of climate system such as the atmosphere and ocean. This paper describes the new coupler, cpl6, contained in the latest version of CCSM,CCSM3. Cpl6 introduces distributed-memory parallelism to the coupler, a class library for important coupler functions, and a standardized interface for component models. Cpl6 is implemented entirely in Fortran90 and uses Model Coupling Toolkit as the base for most of its classes. Cpl6 gives improved performance over previous versions and scales well on multiple platforms.

  13. Spectral characteristics of fiber couplers for FTTx networks

    Science.gov (United States)

    Vitasek, Jan; Latal, Jan; Koudelka, Petr; Vasinek, Vladimir; Bocheza, Jiri; Hejduk, Stanislav

    2012-06-01

    This article deals with spectral characteristics measurement of fiber couplers which are used for FTTx networks. Due to WDM systems we are able to communicate with several wavelengths at a time. In xPON systems the data transmission runs at wavelengths 1310 nm, 1490 and 1550 nm, in case of using singlemode fibers, or at 850 nm and 1300 nm in case of using multimode fibers. The target of this work is a testing how the individual parameters of fiber coupler behave whether broad spectrum light source is connected to the input. In sum it was measured four most often used fiber couplers, fiber coupler in port configuration 1x2 with coupling ratio 50/50%, fiber coupler in port configuration 1x2 with coupling ratio 30/70%, fiber coupler in port configuration 1x2 with coupling ratio 10/90% and fiber coupler in port configuration 1×4 with coupling ratio 4×25%. For these fiber couplers it was set insertion losses, coupling ratios, homogeneities and total losses by using a broad spectrum light source. The results are valuable information for companies which deal with optical networks.

  14. Transcriptional analysis and regulatory signals of the hom-thrB cluster of Brevibacterium lactofermentum.

    Science.gov (United States)

    Mateos, L M; Pisabarro, A; Pátek, M; Malumbres, M; Guerrero, C; Eikmanns, B J; Sahm, H; Martín, J F

    1994-01-01

    Two genes, hom (encoding homoserine dehydrogenase) and thrB (encoding homoserine kinase), of the threonine biosynthetic pathway are clustered in the chromosome of Brevibacterium lactofermentum in the order 5' hom-thrB 3', separated by only 10 bp. The Brevibacterium thrB gene is expressed in Escherichia coli, in Brevibacterium lactofermentum, and in Corynebacterium glutamicum and complements auxotrophs of all three organisms deficient in homoserine kinase, whereas the Brevibacterium hom gene did not complement two different E. coli auxotrophs lacking homoserine dehydrogenase. However, complementation was obtained when the homoserine dehydrogenase was expressed as a fusion protein in E. coli. Northern (RNA) analysis showed that the hom-thrB cluster is transcribed, giving two different transcripts of 2.5 and 1.1 kb. The 2.5-kb transcript corresponds to the entire cluster hom-thrB (i.e., they form a bicistronic operon), and the short transcript (1.1 kb) originates from the thrB gene. The promoter in front of hom and the hom-internal promoter in front of thrB were subcloned in promoter-probe vectors of E. coli and corynebacteria. The thrB promoter is efficiently recognized both in E. coli and corynebacteria, whereas the hom promoter is functional in corynebacteria but not in E. coli. The transcription start points of both promoters have been identified by primer extension and S1 mapping analysis. The thrB promoter was located in an 87-bp fragment that overlaps with the end of the hom gene. A functional transcriptional terminator located downstream from the cluster was subcloned in terminator-probe vectors. Images PMID:7961509

  15. Broadband fiber-chip zero-order surface grating coupler with 0.4  dB efficiency.

    Science.gov (United States)

    Sánchez-Postigo, Alejandro; Gonzalo Wangüemert-Pérez, J; Luque-González, José Manuel; Molina-Fernández, Íñigo; Cheben, Pavel; Alonso-Ramos, Carlos A; Halir, Robert; Schmid, Jens H; Ortega-Moñux, Alejandro

    2016-07-01

    Surface grating couplers enable efficient coupling of light between optical fibers and nanophotonic waveguides. However, in conventional grating couplers, the radiation angle is intrinsically wavelength dependent, thereby limiting their operation bandwidth. In this Letter, we present a zero-order surface grating coupler in silicon-on-insulator which overcomes this limitation by operating in the subwavelength regime. By engineering the effective refractive index of the grating region, both high coupling efficiency and broadband operation bandwidth are achieved. The grating is assisted by a silicon prism on top of the waveguide, which favors upward radiation and minimizes power losses to substrate. Using a linear apodization, our design achieves a coupling efficiency of 91% (-0.41  dB) and a 1-dB bandwidth of 126 nm.

  16. High temperature superconducting axial field magnetic coupler: realization and test

    Science.gov (United States)

    Belguerras, L.; Mezani, S.; Lubin, T.; Lévêque, J.; Rezzoug, A.

    2015-09-01

    Contactless torque transmission through a large airgap is required in some industrial applications in which hermetic isolation is necessary. This torque transmission usually uses magnetic couplers, whose dimension strongly depends on the airgap flux density. The use of high temperature superconducting (HTS) coils to create a strong magnetic field may constitute a solution to reduce the size of the coupler. It is also possible to use this coupler to replace a torque tube in transmitting the torque produced by a HTS motor to its load. This paper presents the detailed construction and tests of an axial field HTS magnetic coupler. Pancake coils have been manufactured from BSCCO tape and used in one rotor of the coupler. The second rotor is mainly composed of NdFeB permanent magnets. Several tests have been carried out showing that the constructed coupler is working properly. A 3D finite element (FE) model of the studied coupler has been developed. Airgap magnetic field and torque measurements have been carried out and compared to the FE results. It has been shown that the measured and the computed quantities are in satisfactory agreement.

  17. Biologie cellulaire des homéoprotéines (2013) | Homéoprotéines et plasticité cellulaire (2014)

    OpenAIRE

    Joliot, Alain

    2016-01-01

        Responsable : Alain Joliot Recherche Mécanismes du transfert intercellulaire des homéoprotéines Au cours de cette année, l’analyse approfondie de lipides spécifiques, les PIP2, dans le transfert intercellulaire des homéoprotéines nous permet de proposer un rôle central de la membrane plasmique dans la répartition des homéoprotéines entre milieu intra- et extracellulaire. En effet, la modulation spécifique de ces lipides au niveau de la membrane plasmique perturbe aussi bien la sécrétion q...

  18. Compact and highly-efficient polarization independent vertical resonant couplers for active-passive monolithic integration.

    Science.gov (United States)

    Galarza, Marko; Van Thourhout, Dries; Baets, Roel; Lopez-Amo, Manuel

    2008-06-09

    Compact low-loss polarization independent vertical coupling between a 1.55 microm InGaAsP bulk active waveguide and a passive waveguide based on bimodal interference is presented. Simulation results show low coupling loss (<0.1 dB) over coupler lengths more than 5 times shorter than using the adiabatic design. The concept avoids submicron photolithographic features and shows acceptable fabrication tolerances.

  19. Substrate Integrated Waveguide hybrid coupler with integrated filter for radar applications

    OpenAIRE

    Mira, Fermín; Llamas-Garro, Ignacio; Georgiadis, Apostolos; San Blas, A.A.

    2015-01-01

    This paper proposes a substrate integrated waveguide (SIW) 180 degrees hybrid coupler with an integrated filter. This device operates at 24.1 GHz for radar applications and the filter removes the frequency of 22.1 GHz coming from the local oscillator. This device is the RF passive part of a single balanced diode mixer. The passive part has been designed, fabricated and measured.

  20. An analogue of the Hom functor and a generalized nuclear democracy theorem

    CERN Document Server

    Li, H

    1997-01-01

    We give an analogue of the Hom functor and prove a generalized form of the nuclear democracy theorem of Tsuchiya and Kanie by using a notion of tensor product for two modules for a vertex operator algebra.

  1. Waveguide Multimode Directional Coupler for Harvesting Harmonic Power from the Output of Traveling-Wave Tube Amplifiers

    Science.gov (United States)

    Simons, Rainee N.; Wintucky, Edwin G.

    2017-01-01

    The paper presents the design, fabrication, and test results for a novel waveguide multimode directional coupler (MDC). The coupler fabricated from dissimilar frequency band waveguides, is capable of isolating power at the 2nd harmonic frequency from the fundamental power at the output port of a high power traveling-wave tube amplifier. The major advantage of the MDC is significantly lower insertion loss compared to a diplexer. The presentation slides for the paper that was approved is attached. The tracking number for the paper that was approved is TN 37015.

  2. HomPPI: a class of sequence homology based protein-protein interface prediction methods

    Directory of Open Access Journals (Sweden)

    Dobbs Drena

    2011-06-01

    Full Text Available Abstract Background Although homology-based methods are among the most widely used methods for predicting the structure and function of proteins, the question as to whether interface sequence conservation can be effectively exploited in predicting protein-protein interfaces has been a subject of debate. Results We studied more than 300,000 pair-wise alignments of protein sequences from structurally characterized protein complexes, including both obligate and transient complexes. We identified sequence similarity criteria required for accurate homology-based inference of interface residues in a query protein sequence. Based on these analyses, we developed HomPPI, a class of sequence homology-based methods for predicting protein-protein interface residues. We present two variants of HomPPI: (i NPS-HomPPI (Non partner-specific HomPPI, which can be used to predict interface residues of a query protein in the absence of knowledge of the interaction partner; and (ii PS-HomPPI (Partner-specific HomPPI, which can be used to predict the interface residues of a query protein with a specific target protein. Our experiments on a benchmark dataset of obligate homodimeric complexes show that NPS-HomPPI can reliably predict protein-protein interface residues in a given protein, with an average correlation coefficient (CC of 0.76, sensitivity of 0.83, and specificity of 0.78, when sequence homologs of the query protein can be reliably identified. NPS-HomPPI also reliably predicts the interface residues of intrinsically disordered proteins. Our experiments suggest that NPS-HomPPI is competitive with several state-of-the-art interface prediction servers including those that exploit the structure of the query proteins. The partner-specific classifier, PS-HomPPI can, on a large dataset of transient complexes, predict the interface residues of a query protein with a specific target, with a CC of 0.65, sensitivity of 0.69, and specificity of 0.70, when homologs of

  3. Multiplexed Energy Coupler for Rotating Equipment

    Science.gov (United States)

    Zhao, Xiaoliang

    2011-01-01

    A multiplexing antenna assembly can efficiently couple AC signal/energy into, or out of, rotating equipment. The unit only passes AC energy while blocking DC energy. Concentric tubes that are sliced into multiple pieces are assembled together so that, when a piece from an outer tube aligns well with an inner tube piece, efficient energy coupling is achieved through a capacitive scheme. With N outer pieces and M inner pieces, an effective N x M combination can be achieved in a multiplexed manner. The energy coupler is non-contact, which is useful if isolation from rotating and stationary parts is required. Additionally, the innovation can operate in high temperatures. Applications include rotating structure sensing, non-contact energy transmission, etc.

  4. Modal-noise generation in biconical-taper couplers.

    Science.gov (United States)

    Kawasaki, B S; Hill, K O; Tremblay, Y

    1981-10-01

    The modal noise resulting from the dividing of coherent light in fused biconical-taper star and access couplers is measured. The theoretical explanation of the results is presented. It is found that modal-noise generation is not severe even in those cases in which the light is strongly subdivided by a biconical-taper star coupler with a large number of ports. The performance of most digital fiber systems using such couplers is not expected to be significantly degraded by the measured levels of modal noise.

  5. High-efficiency chirality-modulated spoof surface plasmon meta-coupler.

    Science.gov (United States)

    Duan, Jingwen; Guo, Huijie; Dong, Shaohua; Cai, Tong; Luo, Weijie; Liang, Zhongzhu; He, Qiong; Zhou, Lei; Sun, Shulin

    2017-05-02

    Efficiently exciting surface plasmon polaritons (SPP) is highly desired in many photonic applications, but most approaches (such as prism and grating couplers) cannot control flexibly their SPP excitation directions. While Pancharatnam-Berry (PB) metasurfaces were recently proposed to achieve direction-controllable SPP excitations, such scheme suffers from low-efficiency issue due to both direct reflections at the coupler surface and the mode mismatch between the coupler and the guiding-out plasmonic structure. In this article, we solve these issues via imposing two criterions to guide design both the metasurface and the plasmonic metal, based on which a direction-controllable SPP excitation with very high efficiency can be realized. As a proof of concept, we designed/fabricated a realistic device working in the microwave regime, and performed both near-field and far-field measurements to demonstrate that it can achieve an spoof SPP conversion efficiency ~78%, much higher than previous devices. Full-wave simulations are in good agreement with experiments, showing that the efficiency can be further pushed to 92% with optimized designs. Our findings can stimulate spoof SPP-related applications, particularly can help enhance the spin-dependent light-matter interactions in low frequency regime.

  6. Methodological development of the Hoeven Outcome Monitor (HOM): A first step towards a more evidence based medicine in forensic mental health.

    Science.gov (United States)

    Keune, Lobke H; de Vogel, Vivienne; van Marle, Hjalmar J C

    2016-01-01

    To comply with the need for a more evidence based risk assessment and management in forensic mental health, an outcome monitor is being developed in the Dutch forensic psychiatric centre Van der Hoeven Kliniek in Utrecht, the Hoeven Outcome Monitor (HOM). Conform evidence based medicine (EBM) guidelines, the HOM is subdivided into three consecutive stages, (1) the evaluation stage, (2) the aetiology stage and (3) the implementation stage. In this article an account is provided for the design of the evaluation stage. To account for predicaments in previous research that pertain to a lack of uniformity and disregard of specific context- and patient-related characteristics, a macro-, meso- and micro-treatment evaluation instrument is developed. This instrument provides for the first step to build an evidence base for specific interventions and treatments in forensic psychiatry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Measurements and Analysis of Longitudinal HOM Driven Coupled Bunch Modes in PEP-II Rings

    Energy Technology Data Exchange (ETDEWEB)

    Mastorides, T; Rivetta, C.; Fox, J.D.; Winkle, D.Van; /SLAC

    2008-07-07

    The growth rates of the longitudinal higher-order impedance-driven beam modes have greatly increased since the initial PEP-II design and commissioning. This increase is attributed to the addition of 6 1.2MW RF stations with 8 accelerating cavities in the HER and 2 1.2MW RF stations with 4 accelerating cavities in the LER, which allowed operations at twice the design current and almost four times the luminosity. As a result, the damping requirements for the longitudinal feedback have greatly increased since the design, and the feedback filters and control schemes have evolved during PEP-II operations. In this paper, growth and damping rate data for the higher-order mode (HOM) driven coupled-bunch modes are presented from various PEP-II runs and are compared with historical estimates during commissioning. The effect of noise in the feedback processing channel is also studied. Both the stability and performance limits of the system are analyzed.

  8. Investigations and Simulations of All optical Switches in linear state Based on Photonic Crystal Directional Coupler

    Directory of Open Access Journals (Sweden)

    S. Maktoobi

    2014-10-01

    Full Text Available Switching is a principle process in digital computers and signal processing systems. The growth of optical signal processing systems, draws particular attention to design of ultra-fast optical switches. In this paper, All Optical Switches in linear state Based On photonic crystal Directional coupler is analyzed and simulated. Among different methods, the finite difference time domain method (FDTD is a preferable method and is used. We have studied the application of photonic crystal lattices, the physics of optical switching and photonic crystal Directional coupler. In this paper, Electric field intensity and the power output that are two factors to improve the switching performance and the device efficiency are investigated and simulated. All simulations are performed by COMSOL software.

  9. Direct UV-written broadband directional broadband planar waveguide couplers

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    We report the fabrication of broadband directional couplers by direct UV-writing. The fabrication process is shown to be beneficial, robust and flexible. The components are compact and show superior performance in terms of loss and broadband operation....

  10. Biconical-taper single-mode fiber coupler.

    Science.gov (United States)

    Kawasaki, B S; Hill, K O; Lamont, R G

    1981-07-01

    Single-mode fiber couplers produced as fused biconical-taper structures are reported on. The devices exhibit low loss (0.5 dB), arbitrary branching ratio, polarization independence, and broadband operation in wavelength.

  11. Unconsumed precursors and couplers after formation of oxidative hair dyes

    DEFF Research Database (Denmark)

    Rastogi, Suresh Chandra; Søsted, Heidi; Johansen, Jeanne Duus

    2006-01-01

    Contact allergy to hair dye ingredients, especially precursors and couplers, is a well-known entity among consumers having hair colouring done at home or at a hairdresser. The aim of the present investigation was to estimate consumer exposure to some selected precursors (p-phenylenediamine, toluene......-2,5-diamine) and couplers (3-aminophenol, 4-aminophenol, resorcinol) of oxidative hair dyes during and after hair dyeing. Concentrations of unconsumed precursors and couplers in 8 hair dye formulations for non-professional use were investigated, under the conditions reflecting hair dyeing. Oxidative...... hair dye formation in the absence of hair was investigated using 6 products, and 2 products were used for experimental hair dyeing. In both presence and absence of hair, significant amounts of unconsumed precursors and couplers remained in the hair dye formulations after final colour development. Thus...

  12. HOM electronics and code to probe beam centring on 3.9 GHz cavities

    CERN Document Server

    Zhang, P

    2014-01-01

    The work within sub-task 10.5.1 was aimed at developing electronics for beam position monitoring (BPM) based on Higher-Order Modes (HOM) excited by electron beams in 3.9 GHz cavities in the FLASH linac at DESY, Hamburg, defining realistic specifications and proving that these signals can be used for beam centering. A series of measurements with devices like a fast oscilloscopes and a real-time spectrum analyzer, as well as with specially designed test electronics. These measurements in conjunction with the simulations made by the other 2 sub-tasks have enabled us to find two spectra regions suitable for use as BPM: modes with strong coupling to the beam around 5.4 GHz, enabling precise monitoring (resolution of ca 20 μm rms) within the whole 4-cavity module, and localized modes at ca.9 GHz for localized measurements in each cavity (resolution of ca 50 mm rms). Various data analysis approaches have been studied. Based on the EuCARD work the HOMBPM electronics has been designed and is now being built at FNAL. ...

  13. Suppression of multipacting in high power RF couplers operating with superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ostroumov, P.N., E-mail: ostroumov@frib.msu.edu [Facility for Rare Isotope Beams (FRIB), Michigan State University, East Lansing, MI 48824 (United States); Kazakov, S. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Morris, D.; Larter, T.; Plastun, A.S.; Popielarski, J.; Wei, J.; Xu, T. [Facility for Rare Isotope Beams (FRIB), Michigan State University, East Lansing, MI 48824 (United States)

    2017-06-01

    Capacitive input couplers based on a 50 Ω coaxial transmission line are frequently used to transmit RF power to superconducting (SC) resonators operating in CW mode. It is well known that coaxial transmission lines are prone to multipacting phenomenon in a wide range of RF power level and operating frequency. The Facility for Rare Isotope Beams (FRIB) being constructed at Michigan State University includes two types of quarter wave SC resonators (QWR) operating at 80.5 MHz and two types of half wave SC resonators (HWR) operating at 322 MHz. As was reported in ref. [1] a capacitive input coupler used with HWRs was experiencing strong multipacting that resulted in a long conditioning time prior the cavity testing at design levels of accelerating fields. We have developed an insert into 50 Ω coaxial transmission line that provides opportunity to bias the RF coupler antenna and protect the amplifier from the bias potential in the case of breakdown in DC isolation. Two of such devices have been built and are currently used for the off-line testing of 8 HWRs installed in the cryomodule.

  14. Calibration of the ERL cavity FPC and PU couplers

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, H.; Johnson, E.; Kayran, D.

    2010-04-05

    The performance parameters of a superconducting cavity, notably accelerating field and quality factor, are first obtained in a cryogenic vertical test Dewar, and again after the final assembly in its cryostat. The tests involve Network Analyzer (NA) measurements in which the cavity is excited through an input coupler and the properties are obtained from the reflected signal at the input and the transmitted signal from the output coupler. The interpretation of the scattering coefficients in terms of field strength requires the knowledge of the Fundamental Power Coupler (FPC) and Pick-Up (PU) coupler strength, as expressed by their 'external' and Q{sub FPC} Q{sub PU}. The coupler strength is independent of the field level or cavity losses and thus can be determined at low levels with the scattering coefficients S{sub 11} and S{sub 21}, assuming standard 50 {Omega} terminations in the network analyzer. Also needed is the intrinsic cavity parameter, R{sub a} /Q{sub 0} {triple_bond} {l_brace}R/Q{r_brace}, a quantity independent of field or losses which must be obtained from simulation programs, such as the Microwave Studio.

  15. Vestes que falam: a tecelagem e as personagens femininas dos poemas homéricos

    Directory of Open Access Journals (Sweden)

    Lilian Amadei Sais

    2015-12-01

    Full Text Available O objetivo desse artigo é mostrar de que forma as vestes são apresentadas na sociedade homérica. Podemos observar que a tecelagem, sendo um trabalho exclusivamente feminino em Homero, é importante para que as mulheres obtenham prestígio e fama. A Odisseia nos mostra que o oferecimento de roupas como presente era uma etapa importante na cena típica de hospitalidade, consolidando os laços existentes entre anfitrião e hóspede. Por fim, argumentamos que na narrativa homérica a vestimenta possui capacidade de comunicação.

  16. Ultrawideband photonic crystal fiber coupler for multiband optical imaging system.

    Science.gov (United States)

    Ryu, Seon Young; Choi, Hae Young; Choi, Eun Seo; Tomov, Ivan; Chen, Zhongping; Lee, Byeong Ha

    2010-04-01

    We report a photonic crystal fiber (PCF) coupler having an ultrawide spectral bandwidth keeping single mode operation. The use of the PCF coupler in a fiber-based optical coherence tomography (OCT) system enables us to handle the wide spectral bands of various light sources, including superluminescent diodes (SLDs) at 1300 nm and 820 nm, Ti:sapphire lasers, and white-light sources. The multiband imaging performances of the PCF-based OCT system are demonstrated by obtaining dental images at 1300 nm and 820 nm with the same setup. In addition, we show that the PCF coupler could cover the spectrum over a one octave span and guide both the fundamental wave (1030 nm) and the second harmonic wave (515 nm) simultaneously.

  17. Simulations of optical sensors fabricated from metallic rods couplers

    Energy Technology Data Exchange (ETDEWEB)

    Singh, M. R. [Department of Physics and Astronomy, Western University Ontario, London, Ontario N6A 3K7 (Canada); Balakrishanan, Shankar [Department of Physics and Astronomy, Western University Ontario, London, Ontario, Canada, N6A 3K7 and Lawson Health Research Institute, 268, Grosvenor Street, London, Ontario N6A 4V2 (Canada)

    2014-03-31

    We have developed the optical sensing mechanism of photonic couplers fabricated from the periodically arranged metallic rods. The metallic rod lattice is embedded between two dielectric material waveguides. This structure is called metallic coupler. Using the transfer matrix method, expressions for the reflection and transmission coefficients of electromagnetic wave propagating in waveguides have been obtained. We found that for certain energies, the electromagnetic wave is totally reflected from the coupler. Similarly, for a certain energy range the light is totally transmitted. It has also been found that by changing the periodicity of the metallic rods, the transmitted energy can be reflected. The periodicity of the metallic lattice can be modified by applying an external stress or pressure. In other words, the system can be used as stress and pressure sensors. The present findings can be used to make new types photonic sensors.

  18. Electrooptic Waveguide Directional Coupler Modulator in Aluminum Gallium Arsenide-Gallium Arsenide.

    Science.gov (United States)

    Khan, Mujibun Nisa

    A novel optical waveguide intensity modulator in aluminum gallium arsenide and gallium arsenide material system is modeled, designed, and experimentally demonstrated at 0.83 μm wavelength. The modulator utilizes the linear electrooptic effect in a coupled waveguide structure to achieve high extinction ratio at low drive voltage. The device structure consists of a differentially -etched ridge directional coupler, where the ridge height in the gap is smaller that that of the outer sides. The effective index and semivectorial finite difference modeling techniques are developed to analyze the single ridge guides and directional coupler structures. The mode structure results from the two models are compared and the limitations of the effective index method are determined. The differential -etch design is employed to reduce the length as well as the drive voltage of the modulator. A modulation voltage of 2 volts for a 3.5-mm-long device is achieved, which is the lowest reported in literature. These results are compared with those obtained from the simplified analytical expressions for conventional couplers, and higher performance expected from the differential-etch design is verified. The modulator extinction ratio is measured to be 13 dB at 2 volts. The measured optical propagation loss of approximately 3.4 dB/cm for the modulator is speculated to be primarily due to the surface morphology of the epitaxially-grown material, and the light scattering from rough ridge walls produced during the anisotropic dry etching process. The high microwave loss of 15 dB/cm calculated for the modulator electrode design suggests a trade-off between the modulation voltage and the bandwidth, which is expected to be limited to 500 MHz. The measurement of the modulator frequency response up to 100 KHz is presented, because of the test limitations at higher frequencies due to the weak modulated intensity signals.

  19. Transmission and Distribution of Optical Field in Prism Coupler

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C Q; Chen, M [College of Physics and Electronics Information, Hunan Institute of Science and Technology, Yueyang 414006 (China); Liu, J; Wan, Z M; Luo, Z M [College of Information and Communication Engineering, Hunan Institute of Science and Technology, Yueyang 414006 (China); Tian, P, E-mail: namecqh@yahoo.com.cn [College of Optoelectronic Science and Engineering, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074 (China)

    2011-02-01

    Transmission and distribution characteristics of optical field in prism coupler are studies, and the phase matching function of prism coupler is deduced based on coupled wave theory. It is shown that the stable light field distribution and mode pattern are determined by its own geometric and dielectric parameters, but have nothing to do with the categories of incident light sources. It is also found that the coupling effect would generate between waveguides through evanescent field. Our numerical simulation is based on the finite difference time domain method with perfectly matched layer absorbing boundary condition. The simulation program is compiled in MATLAB. The simulation results are analyzed carefully.

  20. Study of optical output couplers for submillimeter wavelength backward-wave oscillators (BWO's)

    Science.gov (United States)

    Cook, Jerry D.; Stankiewicz, Norbert; Podany, Mark

    1989-01-01

    Several scaled experiments of optical output couplers for submillimeter backward-wave oscillators (BWOs). Various designs of planar antennas (Vivaldi horns) lens-feed systems (hyperhemispherical lens) were constructed and tested between 20 and 100 GHz using a spectrum analyzer. The lens system was also tested at 337 GHz using a CO2 pumped FIR laser. It is found that Vivaldi horns have unsatisfactory resonances, perhaps because the horns studied were relatively short. Several techniques to maximize and flatten the frequency response of these horns are presented. The results suggest that alternate coupling schemes are superior to Vivaldi horns.

  1. Some remarks about monoidal Hom-algebras | Alonso Álvarez ...

    African Journals Online (AJOL)

    In this paper, for C a strict braided monoidal category with tensor product , we improve the denition of Hom-associative algebra by removing the multiplicativity condition of the automorphism . After that we state the close connection between the classical notions of (co)algebra, (co)module and Hopf algebra and the ...

  2. Highly efficient vertical fiber interfacing grating coupler with bilayer anti-reflection cladding and backside metal mirror

    Science.gov (United States)

    Zhang, Zanyun; Huang, Beiju; Zhang, Zan; Cheng, Chuantong; Liu, Hongwei; Li, Hongqiang; Chen, Hongda

    2017-05-01

    A highly efficient bidirectional grating coupler for perfectly vertical coupling is designed. With a Si3N4/SiO2 bilayer structure and a backside metal mirror acting as anti-reflection cladding (ARC) and substrate reflector respectively, the coupling efficiency can be greatly enhanced for a cost-effective uniform grating coupler. To maximize the grating coupling, all the grating parameters including the bilayer thicknesses are fully optimized using numerical simulation method. As a design trade-off between coupling efficiency (CE) and optical bandwidth (OB), CE of 88.3% (-0.54 dB) and 1-dB bandwidth of 61 nm can be obtained. In addition, this grating coupler shows strong fiber misalignment tolerance. With a 2 μm fiber misalignment, the coupling loss increases by less than 0.5 dB and the up-reflection loss increases by less than 2 dB. Also it is found that the splitting behavior of the grating is quite stable near the grating resonant wavelength. Such characteristics make this device very attractive for low-cost photonic packaging and Mach-Zehnder type device applications. In addition, two optimal designs are presented based on the Particle Swarm Optimization (PSO) method and genetic algorithm (GA). Numerical calculated results show that the coupling efficiency at center wavelength can be further improved compared to that of the balanced design. However, the optical bandwidth suffer at a expense. At last, Fourier analysis of the grating is carried out to analyze the optical field profile and frequency spectrum of the grating region. It is believed such a grating structure can provide flexible designs for different coupler requirements and applications.

  3. Synthesis and analysis of coupler curves with combined planar cam ...

    African Journals Online (AJOL)

    Cam and follower mechanisms are widely used to convert a rotary input motion into a controlled reciprocating or oscillating motion as output in machines or robots. As this mechanism has an ability to provide unlimited variety of output motions. Many works are done on the synthesis of coupler curves or path generation ...

  4. Synthesis and analysis of coupler curves with combined planar cam ...

    African Journals Online (AJOL)

    user

    Proposed CCM successfully applied to the complex path generation problems of profile cutting machine like square, circle and figure eight profiles. A method ... synthesize the automotive valve trains. The work presented by ... Four bar is a kinematic equivalent mechanism of profile cutting machine. As coupler point defines ...

  5. Nonclassical properties of a contradirectional nonlinear optical coupler

    Energy Technology Data Exchange (ETDEWEB)

    Thapliyal, Kishore [Jaypee Institute of Information Technology, A-10, Sector-62, Noida, UP-201307 (India); Pathak, Anirban, E-mail: anirban.pathak@gmail.com [Jaypee Institute of Information Technology, A-10, Sector-62, Noida, UP-201307 (India); RCPTM, Joint Laboratory of Optics of Palacky University and Institute of Physics of Academy of Science of the Czech Republic, Faculty of Science, Palacky University, 17. listopadu 12, 771 46 Olomouc (Czech Republic); Sen, Biswajit [Department of Physics, Vidyasagar Teachers' Training College, Midnapore 721101 (India); Perřina, Jan [RCPTM, Joint Laboratory of Optics of Palacky University and Institute of Physics of Academy of Science of the Czech Republic, Faculty of Science, Palacky University, 17. listopadu 12, 771 46 Olomouc (Czech Republic); Department of Optics, Palacky University, 17. listopadu 12, 771 46 Olomouc (Czech Republic)

    2014-10-24

    We investigate the nonclassical properties of output fields propagated through a contradirectional asymmetric nonlinear optical coupler consisting of a linear waveguide and a nonlinear (quadratic) waveguide operated by second harmonic generation. In contrast to the earlier results, all the initial fields are considered weak and a completely quantum-mechanical model is used here to describe the system. Perturbative solutions of Heisenberg's equations of motion for various field modes are obtained using Sen–Mandal technique. Obtained solutions are subsequently used to show the existence of single-mode and intermodal squeezing, single-mode and intermodal antibunching, two-mode and multi-mode entanglement in the output of contradirectional asymmetric nonlinear optical coupler. Further, existence of higher order nonclassicality is also established by showing the existence of higher order antibunching, higher order squeezing and higher order entanglement. Variation of observed nonclassical characters with different coupling constants and phase mismatch is discussed. - Highlights: • Nonclassicalities in fields propagating through a directional coupler is studied. • Completely quantum-mechanical description of the coupler is provided. • Analytic solutions of Heisenberg equations of motion for various modes are obtained. • Existence of lower order and higher order entanglement is shown. • Variation of nonclassicalities with phase-mismatch and coupling constants is studied.

  6. High efficiency input-output prism waveguide coupler: an analysis.

    Science.gov (United States)

    Sarid, D

    1979-09-01

    The theory and experimental results of the performance of a practical prism waveguide input-output coupler are presented. The coupling scheme, which results in a 94% coupling efficiency, uses a single prism for both input and output coupling, with the light propagating 1 cm in the LiNbO(3) Ti in diffused waveguide.

  7. Synthesis and analysis of coupler curves with combined planar cam ...

    African Journals Online (AJOL)

    user

    point on a linkage to move along a prescribed trajectory (path generation), but these methods restrict the number of precision points or coordinates. Increase in .... Aim was to guide a coupler point along an elliptical path, defined by a set of 27 precision points; this specific path generation problem was the interest of ...

  8. Characteristics Of Fused Couplers Below Cut-Off

    Science.gov (United States)

    Meyer, T. J.; Tekippe, V. J.

    1989-02-01

    A number of different architectures are being explored for the utilization of optical fiber in the subscriber loop. In addition to reliability and maintainability, cost is a prime consideration since full implementation of fiber in the local loop will not occur until it is economically viable. It is becoming increasingly clear that in order to accommodate a number of ISDN applications, including high definition television (HDTV), singlemode fiber with a singlemode laser at the terminal end will be required. The situation at the subscriber end is quite different, however. The data rates are expected to be low on the return path to allow for POTS ( plain old telephone service) and some data transfer. When this requirement is combined with cost and reliability considerations, the inexpensive lasers developed for the CD (compact disk) market become quite attractive. The biggest disadvantage of this source is that the fiber which is optimized for singlemode operation at 1300nm tends to be multimode in the 800nm band where these lasers operate. Previous papers have considered such effects as modal noise and pulse dispersion when using these lasers with fiber that is singlemode in the 1300nm band.[1] Another consideration is the passive components required to implement such an architecture. Figure 1 shows a typical bidirectional design with full duplex operation on a single fiber. The key component is the 800/1300 wavelength division multiplexer/demultiplexer (WDM). Because of the multimode nature of the fiber in the 800nm band, all fiber approaches to fabricating the WDM, such as the fused beconical taper (FBT) approach, raise new issues which are not encountered, for example, with 1300/1500nm WDM's.[2] In this paper we discuss the effects of the multimode behavior of the fiber on the performance of fused couplers and WDM's.

  9. Identification of Human Junctional Adhesion Molecule 1 as a Functional Receptor for the Hom-1 Calicivirus on Human Cells

    Directory of Open Access Journals (Sweden)

    Stanislav V. Sosnovtsev

    2017-02-01

    Full Text Available The Hom-1 vesivirus was reported in 1998 following the inadvertent transmission of the animal calicivirus San Miguel sea lion virus to a human host in a laboratory. We characterized the Hom-1 strain and investigated the mechanism by which human cells could be infected. An expression library of 3,559 human plasma membrane proteins was screened for reactivity with Hom-1 virus-like particles, and a single interacting protein, human junctional adhesion molecule 1 (hJAM1, was identified. Transient expression of hJAM1 conferred susceptibility to Hom-1 infection on nonpermissive Chinese hamster ovary (CHO cells. Virus infection was markedly inhibited when CHO cells stably expressing hJAM were pretreated with anti-hJAM1 monoclonal antibodies. Cell lines of human origin were tested for growth of Hom-1, and efficient replication was observed in HepG2, HuH7, and SK-CO15 cells. The three cell lines (of hepatic or intestinal origin were confirmed to express hJAM1 on their surface, and clustered regularly interspaced short palindromic repeats/Cas9-mediated knockout of the hJAM1 gene in each line abolished Hom-1 propagation. Taken together, our data indicate that entry of the Hom-1 vesivirus into these permissive human cell lines is mediated by the plasma membrane protein hJAM1 as a functional receptor.

  10. Fully etched apodized grating coupler on the SOI platform with −058 dB coupling efficiency

    DEFF Research Database (Denmark)

    Ding, Yunhong; Peucheret, Christophe; Ou, Haiyan

    2014-01-01

    We design and fabricate an ultrahigh coupling efficiency (CE) fully etched apodized grating coupler on the silicon- on-insulator (SOI) platform using subwavelength photonic crystals and bonded aluminum mirror. Fabrication error sensitivity andcoupling angle dependence are experimentally investiga...... investigated. A recordultrahighCE of − 0 . 58 dB with a 3 dB bandwidth of 71 nm and low back reflection are demonstrated....

  11. The Hannover Coupler: Controlled Static Prestress in Round Window Stimulation With the Floating Mass Transducer.

    Science.gov (United States)

    Müller, Mathias; Salcher, Rolf; Lenarz, Thomas; Maier, Hannes

    2017-09-01

    Stimulation of the cochlear round window (RW) with the floating mass transducer (FMT) still suffers from large variation in clinical outcomes. Beside the geometric mismatch between RW and FMT diameter that is a known limiting factor in achieving optimal coupling between actuator and RW membrane, the applied static force between FMT and RW is usually undefined. In this study, the feasibility and efficacy of a specially designed FMT coupler permitting application of static preloads to the RW membrane to optimize FMT-RW coupling was investigated. Experiments were performed in fresh human cadaveric temporal bones. The "Hannover Coupler" FMT-prosthesis has a spherical tip (d=0.5 mm) at the front end and a spring at the prosthesis back that enables the application of static preloads and mobility of the FMT at the same time. Stapes footplate (SFP) displacements in response to acoustic stimulation of the tympanic membrane and to RW stimulation by the FMT were measured by a Laser-Doppler vibrometer. Average SFP displacement responses of ASTM standard F2504-05 compliant temporal bones to RW stimulation by the "Hannover Coupler" were dependent on the applied force (∼0-100 mN) and increased by up to 25 dB at frequencies ≥ 1 kHz. When averaged at speech relevant frequencies (0.5, 1, 2, 4 kHz) SFP displacements showed a global maximum at RW preloads of ∼4 mN. The coupling between FMT and RW membrane was improved by the application of static RW preloads as indicated by increased SFP amplitudes to RW stimulation.

  12. Superconducting Cavity Cryomodule Designs for the Next Generation of CW Linacs: Challenges and Options

    Energy Technology Data Exchange (ETDEWEB)

    Nicol, Thomas [Fermilab; Orlov, Yuriy [Fermilab; Peterson, Thomas [Fermilab; Yakovlev, Vyacheslav [Fermilab

    2014-07-01

    The designs of nearly all superconducting RF (SRF) linacs over the last several years, with one notable exception being CEBAF at Jefferson Lab, have assumed pulsed beam operation with relatively low duty factors. These include the XFEL at DESY, the ILC, the original configuration for Project X at Fermilab, as well as several others. Recently proposed projects, on the other hand, including the LCLS-II at SLAC, the newly configured low and medium energy sections for Project X, and FRIB at Michigan State, to name a few, assume continuous wave or CW operation on quite a large scale with ambitious gradients and cavity performance requirements. This has implications in the cavity design as well as in many parts of the overall cryomodule due to higher dynamic heat loads in the cavities themselves and higher heat loads in the input and high-order-mode (HOM) couplers. Piping internal to the cryomodule, the effectiveness of thermal intercepts, the size of integrated heat exchangers, and many other aspects of the overall design are also affected. This paper will describe some of these design considerations as we move toward the next generation of accelerator projects.

  13. On-chip grating coupler array on the SOI platform for fan-in/fan-out of multi-core fibers with low insertion loss and crosstalk

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ye, Feihong; Peucheret, Christophe

    2014-01-01

    We design and fabricate a compact multi-core fiber fan-in/fan-out using a fully-etched grating coupler array on the SOI platform. Lowest coupling loss of 6.8 dB with 3 dB bandwidth of 48 nm and crosstalk lower than ×32 dB are demonstrated....

  14. Microwave power coupler for a superconducting multiple-cell cavity for accelerator application and its testing procedures

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jianjian [Illinois Inst. of Technology, Chicago, IL (United States)

    2008-12-01

    Superconducting cavity resonators offer the advantage of high field intensity for a given input power, making them an attractive contender for particle accelerator applications. Power coupling into a superconducting cavity employed in a particle accelerator requires unique provisions to maintain high vacuum and cryogenic temperature on the cavity side, while operating with ambient conditions on the source side. Components introduced to fulfill mechanical requirements must show negligible obstruction of the propagation of the microwave with absence of critical locations that may give rise to electron multipaction, leading to a multiple section design, instead of an aperture, a probe, or a loop structure as found in conventional cavities. A coaxial power coupler for a superconducting multiple-cell cavity at 3.9 GHz has been developed. The cavity is intended to be employed as an accelerator to provide enhanced electron beam quality in a free-electron laser in Hamburg (FLASH) user facility. The design of the coupler called for two windows to sustain high vacuum in the cavity and two bellows to accommodate mechanical dimensional changes resulting from cryogenics. Suppression of multipacting was accomplished by the choice of conductor dimensions and materials with low second yield coefficients. Prior to integration with the cavity, the coupler was tested for intrinsic properties in a back-to-back configuration and conditioned for high-power operation with increasing power input. Maximum incident power was measured to be 61 kW. When integrated with the superconducting cavity, a loaded quality factor of 9 x 10 5 was measured by transient method. Coupler return loss and insertion loss were estimated to be around -21 dB and -0.2 dB, respectively.

  15. Diagnostics Upgrades for Investigations of HOM Effects in TESLA-type SCRF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. H. [Fermilab; Edstrom Jr., D.; Ruan, J. [Fermilab; Thurman-Keup, R. [Fermilab; Shin, Y. [Fermilab; Prieto, P. [Fermilab; Eddy, N. [Fermilab; Carlsten, B. E. [Los Alamos

    2017-08-23

    We describe the upgrades to diagnostic capabilities on the Fermilab Accelerator Science and Technology (FAST) electron linear accelerator that will allow investigations of the effects of high-order modes (HOMs) in SCRF cavities on macropulse-average beam quality. We examine the dipole modes in the first pass-band generally observed in the 1.6-1.9 GHz regime for TESLA-type SCRF cavities due to uniform transverse beam offsets of the electron beam. Such cavities are the basis of the accelerators such as the European XFEL and the proposed MaRIE XFEL facility. Preliminary HOM detector data, prototype BPM test data, and first framing camera OTR data with ~20- micron spatial resolution at 250 pC per bunch will be presented.

  16. Beam Fields in an Integrated Cavity, Coupler and Window Configuration

    Energy Technology Data Exchange (ETDEWEB)

    Weathersby, Stephen; Novokhatski, Alexander; /SLAC

    2010-02-10

    In a multi-bunch high current storage ring, beam generated fields couple strongly into the RF cavity coupler structure when beam arrival times are in resonance with cavity fields. In this study the integrated effect of beam fields over several thousand RF periods is simulated for the complete cavity, coupler, window and waveguide system of the PEP-II B-factory storage ring collider. We show that the beam generated fields at frequencies corresponding to several bunch spacings for this case gives rise to high field strength near the ceramic window which could limit the performance of future high current storage rings such as PEP-X or Super B-factories.

  17. Analysis of HOM Problems in the C-ADS Main Linac

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Burn [Chinese Academy of Sciences (CAS), Lanzhou (China). Inst. of Modern Physics; Ng, King Yuen [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2017-05-18

    Excitation of higher-order modes (HOMs) in superconducting cavities may severely affect the operation of the main linac in the Chinese Accelerator Driven System (CADS). Preliminary analysis is made on the effects of beam dynamic, which includes possible longitudinal and transverse emittance enlargements, as well as the possibility of beam breakup. Suggestions are given for further investigation. Comparison is made between the C-ADS and the Fermilab Project X.

  18. Superluminal space-to-time mapping in grating-assisted co-directional couplers.

    Science.gov (United States)

    Ashrafi, Reza; Li, Ming; LaRochelle, Sophie; Azaña, José

    2013-03-11

    A superluminal space-to-time mapping process is reported and numerically validated in grating-assisted (GA) co-directional couplers, e.g. fiber/waveguide long-period gratings (LPGs). We demonstrate that under weak-coupling conditions, the amplitude and phase of the grating complex apodization profile of a GA co-directional coupling device can be directly mapped into the device's temporal impulse response. In contrast to GA counter-directional couplers, this mapping occurs with a space-to-time scaling factor that is much higher than the propagation speed of light in vacuum. This phenomenon opens up a promising new avenue to overcome the fundamental time-resolution limitations of present in-fiber and on-chip optical waveform generation (shaping) and processing devices, which are intrinsically limited by the achievable spatial resolution of fabrication technologies. We numerically demonstrate the straightforward application of the phenomenon for synthesizing customized femtosecond-regime complex optical waveforms using readily feasible fiber LPG designs, e.g. with sub-centimeter resolutions.

  19. Performance improvement of optical fiber coupler with electric heating versus gas heating.

    Science.gov (United States)

    Shuai, Cijun; Gao, Chengde; Nie, Yi; Peng, Shuping

    2010-08-20

    Gas heating has been widely used in the process of fused biconical tapering. However, as the instability and asymmetric flame temperature of gas heating exist, the performance of the optical devices fabricated by this method was affected. To overcome the problems resulting from gas combustion, an electric heater is designed and manufactured using a metal-ceramic (MoSi(2)) as a heating material. Our experimental data show that the fused-taper machine with an electric heater has improved the performance of optical devices by increasing the consistency of the extinction ratio, excess loss, and the splitting ratio over that of the previous gas heating mode. Microcrystallizations and microcracks were observed at the fused region of the polarization-maintaining (PM) fiber coupler and at the taper region with scanning electron microscopy and atomic force microscopy respectively. The distribution of the microcrystallizations and microcracks are nonuniform along the fiber with gas heating, while their distribution is rather uniform with electric heating. These findings show that the novel optical fiber coupler with an electric heater has improved the performance of optical fiber devices by affecting the consistency of the optical parameters and micromorphology of the surface of PM fiber.

  20. Distributed grating-assisted coupler for optical all-dielectric electron accelerator

    Directory of Open Access Journals (Sweden)

    Zhiyu Zhang

    2005-07-01

    Full Text Available A Bragg waveguide consisting of multiple dielectric layers with alternating index of refraction becomes an excellent option to form electron accelerating structure powered by high power laser sources. It provides confinement of a synchronous speed-of-light mode with extremely low loss. However, laser field cannot be coupled into the structure collinearly with the electron beam. There are three requirements in designing input coupler for a Bragg electron accelerator: side coupling, selective mode excitation, and high coupling efficiency. We present a side-coupling scheme using a distributed grating-assisted coupler to inject the laser power into the waveguide. Side coupling is achieved by a grating with a period on the order of an optical wavelength. The phase matching condition results in resonance coupling thus providing selective mode excitation capability. The coupling efficiency is limited by profile matching between the outgoing beam and the incoming beam, which has normally a Gaussian profile. We demonstrate a nonuniform distributed grating structure generating an outgoing beam with a Gaussian profile, therefore, increasing the coupling efficiency.

  1. Measurement of chalcogenide glass optical dispersion using a mid-infrared prism coupler

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Hong (Amy); Anheier, Norman C.; Musgraves, Jonathan D.; Richardson, Kathleen; Hewak, Daniel W.

    2011-05-01

    Physical properties of chalcogenide glass, including broadband infrared transparency, high refractive index, low glass transition temperature, and nonlinear properties, make them attractive candidates for advanced mid-infrared (3 to 12 {micro}m) optical designs. Efforts focused at developing new chalcogenide glass formulations and processing methods require rapid quantitative evaluation of their optical contents to guide the materials research. However, characterization of important optical parameters such as optical dispersion remains a slow and costly process, generally with limited accuracy. The recent development of a prism coupler at the Pacific Northwest National Laboratory (PNNL) now enables rapid, high precision measurement of refractive indices at discrete wavelengths from the visible to the mid-infrared. Optical dispersion data of several chalcogenide glass families were collected using this method. Variations in the optical dispersion were correlated to glass composition and compared against measurements using other methods. While this work has been focused on facilitating chalcogenide glass synthesis, mid-infrared prism coupler analysis has broader applications to other mid-infrared optical material development efforts, including oxide glasses and crystalline materials.

  2. Measurement of thin film parameters with a prism coupler.

    Science.gov (United States)

    Ulrich, R; Torge, R

    1973-12-01

    The prism coupler, known from experiments on integrated optics, can be used to determine the refractive index and the thickness of a light-guiding thin film. Both parameters are obtained simultaneously and with good accuracy by measuring the coupling angles at the prism and fitting them by a theoretical dispersion curve. The fundamentals and limitations. of this method are discussed, its practical use, and mathematical procedures for the evaluation.

  3. Efficient Coupler for a Bessel Beam Dispersive Element

    Science.gov (United States)

    Savchenkov, Anatoliy; Iltchenko, Vladimir; Matsko, Andrey; Le, Thanh; Yu, nan; Maleki, Lute

    2008-01-01

    A document discusses overcoming efficient optical coupling to high orbital momentum modes by slightly bending the taper dispersive element. This little shape distortion is not enough to scramble the modes, but it allows the use of regular, free-beam prism coupling, fiber coupling, or planar fiber on-chip coupling with, ultimately, 100 percent efficiency. The Bessel-beam waveguide is bent near the contact with the coupler, or a curved coupler is used. In this case, every Bessel-beam mode can be successfully coupled to a collimated Gaussian beam. Recently developed Bessel-beam waveguides allow long optical delay and very high dispersion. Delay values may vary from nanoseconds to microseconds, and dispersion promises to be at 100 s/nm. Optical setup consisted of a red laser, an anamorphic prism pair, two prism couplers, and a bent, single-mode fiber attached to prisms. The coupling rate increased substantially and corresponded to the value determined by the anamorphic prism pair.

  4. Wavelength-division-multiplexing fiber coupler based on bending-insensitive holey optical fiber.

    Science.gov (United States)

    Eom, Joo Beom; Lim, Hae-Ryong; Park, Kwan Seob; Lee, Byeong Ha

    2010-08-15

    A wavelength-division-multiplexing (WDM) coupler has been made with a bending-insensitive holey optical fiber (HOF) by using the fused biconical tapered (FBT) method. The transmission band of the proposed HOF WDM coupler could be easily tuned by adjusting the pulling length during the FBT process. Interestingly, it was observed that the air-hole structure of the HOF should be maintained to have the property of a WDM coupler. As the air holes collapse, the HOF WDM exhibits high-pass-filter-like properties. The cross-sectional scanning electron microscope images of the implemented HOF WDM coupler are presented along with the light intensity distribution measured at the coupling region of the coupler. The proposed HOF couplers may also find applications in optical coarse WDM systems and optical fiber sensors.

  5. Total internal reflection-evanescent coupler for fiber-to-waveguide integration of planar optoelectric devices.

    Science.gov (United States)

    Lu, Zhaolin; Prather, Dennis W

    2004-08-01

    We present a method for parallel coupling from a single-mode fiber, or fiber ribbon, into a silicon-on-insulator waveguide for integration with silicon optoelectronic circuits. The coupler incorporates the advantages of the vertically tapered waveguides and prism couplers, yet offers the flexibility of planar integration. The coupler can be fabricated by use of either wafer polishing technology or gray-scale photolithography. When optimal coupling is achieved in our experimental setup, the coupler can be packaged by epoxy bonding to form a fiber-waveguide parallel coupler or connector. Two-dimensional electromagnetic calculation predicts a coupling efficiency of 77% (- 1.14-dB insertion loss) for a silicon-to-silicon coupler with a uniform tunnel layer. The coupling efficiency is experimentally achieved to be 46% (-3.4-dB insertion loss), excluding the loss in silicon and the reflections from the input surface and the output facet.

  6. Optimal RF Conditioning of Advanced Photon Source (APS) Fundamental Power Coupler

    CERN Document Server

    Montesinos, E

    2013-01-01

    Experience at many laboratories regarding conditioning of RF Fundamental Power Couplers (FPC) has shown that it is a very apprehensive and laborious process. While the principle should remain unchanged, which is to gradually increase the rf power applied to the coupler while monitoring the vacuum level, the methodology is sometime different. With coupler lifetime being finite, some RF conditioning methods may be more conservative than others. The basic principle of coupler conditioning is to avoid the phenomena of metallisation, violent electrical discharges or other possible destructive phenomena. This document summarizes an optimized method which has demonstrated its effectiveness and for which the fundamental principles are: • Regulate RF power as a function of vacuum pressure around the coupler as fast as possible. • Apply a longer repetition period than the vacuum reading delay. • Follow the bare principle: low energy for low risk, by delivering pulses to the not yet conditioned coupler, initially...

  7. Simple measurement technique for the coupling coefficient of integrated optical directional couplers.

    Science.gov (United States)

    Kishioka, K; Yip, G L

    1992-05-20

    A simple technique for measuring the coupling coefficient and the power transfer efficiency of the optical directional coupler is presented. This technique consists of measuring Fraunhofer diffraction patterns emerging from the output prism coupler that is placed on the parallel waveguides. The measured values for the K(+)-diffused glass waveguide couplers that are fabricated at different diffusion times are demonstrated. A measurement error of <4% for the coupling coefficient is estimated for the 4-6 mm range of the coupling length.

  8. Identification of Human Junctional Adhesion Molecule 1 as a Functional Receptor for the Hom-1 Calicivirus on Human Cells.

    Science.gov (United States)

    Sosnovtsev, Stanislav V; Sandoval-Jaime, Carlos; Parra, Gabriel I; Tin, Christine M; Jones, Ronald W; Soden, Jo; Barnes, Donna; Freeth, Jim; Smith, Alvin W; Green, Kim Y

    2017-02-14

    The Hom-1 vesivirus was reported in 1998 following the inadvertent transmission of the animal calicivirus San Miguel sea lion virus to a human host in a laboratory. We characterized the Hom-1 strain and investigated the mechanism by which human cells could be infected. An expression library of 3,559 human plasma membrane proteins was screened for reactivity with Hom-1 virus-like particles, and a single interacting protein, human junctional adhesion molecule 1 (hJAM1), was identified. Transient expression of hJAM1 conferred susceptibility to Hom-1 infection on nonpermissive Chinese hamster ovary (CHO) cells. Virus infection was markedly inhibited when CHO cells stably expressing hJAM were pretreated with anti-hJAM1 monoclonal antibodies. Cell lines of human origin were tested for growth of Hom-1, and efficient replication was observed in HepG2, HuH7, and SK-CO15 cells. The three cell lines (of hepatic or intestinal origin) were confirmed to express hJAM1 on their surface, and clustered regularly interspaced short palindromic repeats/Cas9-mediated knockout of the hJAM1 gene in each line abolished Hom-1 propagation. Taken together, our data indicate that entry of the Hom-1 vesivirus into these permissive human cell lines is mediated by the plasma membrane protein hJAM1 as a functional receptor.IMPORTANCE Vesiviruses, such as San Miguel sea lion virus and feline calicivirus, are typically associated with infection in animal hosts. Following the accidental infection of a laboratory worker with San Miguel sea lion virus, a related virus was isolated in cell culture and named Hom-1. In this study, we found that Hom-1 could be propagated in a number of human cell lines, making it the first calicivirus to replicate efficiently in cultured human cells. Screening of a library of human cell surface membrane proteins showed that the virus could utilize human junctional adhesion molecule 1 as a receptor to enter cells and initiate replication. The Hom-1 virus presents a new

  9. Ultra-low loss nano-taper coupler for Silicon-on-Insulator ridge waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    A nano-taper coupler is optimized specially for the transverse-magnetic mode for interfacing light between a silicon-on-insulator ridge waveguide and a single-mode fiber. An ultra-low coupling loss of ~0.36dB is achieved for the nano-taper coupler.......A nano-taper coupler is optimized specially for the transverse-magnetic mode for interfacing light between a silicon-on-insulator ridge waveguide and a single-mode fiber. An ultra-low coupling loss of ~0.36dB is achieved for the nano-taper coupler....

  10. Evaluation on Tensile Strength and Applicability of Tapered Rolled Thread Coupler

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Jinhwan; Choi, Hyoungsuk; Jung, Chiyoung [Pusan National Univ., Busan (Korea, Republic of); Kim, Taejin [Korea Conformity Laboratories, Busan (Korea, Republic of); Seo, Sanghwan [Sammi Precision Co. Ltd., Ulsan (Korea, Republic of)

    2014-05-15

    Various diameters of reinforcing bars, ASTM A 615 Grade 60 11, 14, and 18, are used for construction of Nuclear Power Plant structures. But due to the large diameter of these rebar, placing rebar is difficult. This study suggests a new tapered rolled thread coupler which have improved workability and fastening force. To evaluate tensile strength and applicability, the tensile test are conducted and static load-carrying capacity of rolled thread coupler are evaluated. In the both tensile tests and column tests, the good agreement of load-carrying capacity are shown. Therefore the proposed tapered rolled thread coupler can be applied to the NPP to replace conventional coupler.

  11. Low insertion loss SOI microring resonator integrated with nano-taper couplers

    DEFF Research Database (Denmark)

    Pu, Minhao; Frandsen, Lars Hagedorn; Ou, Haiyan

    2009-01-01

    We demonstrate a microring resonator working at TM mode integrated with nano-taper couplers with 3.6dB total insertion loss. The measured insertion loss of the nano-taper coupler was only 1.3dB for TM mode.......We demonstrate a microring resonator working at TM mode integrated with nano-taper couplers with 3.6dB total insertion loss. The measured insertion loss of the nano-taper coupler was only 1.3dB for TM mode....

  12. 3D Printed Terahertz Focusing Grating Couplers

    Science.gov (United States)

    Jahn, David; Weidenbach, Marcel; Lehr, Jannik; Becker, Leonard; Beltrán-Mejía, Felipe; Busch, Stefan F.; Balzer, Jan C.; Koch, Martin

    2017-06-01

    We have designed, constructed and characterized a grating that focuses electromagnetic radiation at specific frequencies out of a dielectric waveguide. A simple theoretical model predicts the focusing behaviour of these chirped gratings, along with numerical results that support our assumptions and improved the grating geometry. The leaky waveguide was 3D printed and characterized at 120 GHz demonstrating its potential for manipulating terahertz waves.

  13. HomBlocks: A multiple-alignment construction pipeline for organelle phylogenomics based on locally collinear block searching.

    Science.gov (United States)

    Bi, Guiqi; Mao, Yunxiang; Xing, Qikun; Cao, Min

    2018-01-01

    Organelle phylogenomic analysis requires precisely constructed multi-gene alignment matrices concatenated by pre-aligned single gene datasets. For non-bioinformaticians, it can take days to weeks to manually create high-quality multi-gene alignments comprising tens or hundreds of homologous genes. Here, we describe a new and highly efficient pipeline, HomBlocks, which uses a homologous block searching method to construct multiple sequence alignment. This approach can automatically recognize locally collinear blocks among organelle genomes and excavate phylogenetically informative regions to construct multiple sequence alignment in a few hours. In addition, HomBlocks supports organelle genomes without annotation and makes adjustment to different taxon datasets, thereby enabling the inclusion of as many common genes as possible. Topology comparison of trees built by conventional multi-gene and HomBlocks alignments implemented in different taxon categories shows that the same efficiency can be achieved by HomBlocks as when using the traditional method. The availability of Homblocks makes organelle phylogenetic analyses more accessible to non-bioinformaticians, thereby promising to lead to a better understanding of phylogenic relationships at an organelle genome level. HomBlocks is implemented in Perl and is supported by Unix-like operative systems, including Linux and macOS. The Perl source code is freely available for download from https://github.com/fenghen360/HomBlocks.git, and documentation and tutorials are available at https://github.com/fenghen360/HomBlocks. yxmao@ouc.edu.cn or fenghen360@126.com. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. The role of highly oxygenated molecules (HOMs) in determining the composition of ambient ions in the boreal forest

    Science.gov (United States)

    Bianchi, Federico; Garmash, Olga; He, Xucheng; Yan, Chao; Iyer, Siddharth; Rosendahl, Ida; Xu, Zhengning; Rissanen, Matti P.; Riva, Matthieu; Taipale, Risto; Sarnela, Nina; Petäjä, Tuukka; Worsnop, Douglas R.; Kulmala, Markku; Ehn, Mikael; Junninen, Heikki

    2017-11-01

    In order to investigate the negative ions in the boreal forest we have performed measurements to chemically characterise the composition of negatively charged clusters containing highly oxygenated molecules (HOMs). Additionally, we compared this information with the chemical composition of the neutral gas-phase molecules detected in the ambient atmosphere during the same period. The chemical composition of the ions was retrieved using an atmospheric pressure interface time-of-flight mass spectrometer (APi-TOF-MS) while the gas-phase neutral molecules (mainly sulfuric acid and HOMs) were characterised using the same mass spectrometer coupled to a nitrate-based chemical ionisation unit (CI-APi-TOF). Overall, we divided the identified HOMs in two classes: HOMs containing only carbon, hydrogen and oxygen and nitrogen-containing HOMs or organonitrates (ONs). During the day, among the ions, in addition to the well-known pure sulfuric acid clusters, we found a large number of HOMs clustered with nitrate (NO3-) or bisulfate (HSO4-), with the first one being more abundant. During the night, the distribution of ions, mainly composed of HOM clustered with NO3-, was very similar to the neutral compounds that are detected in the CI-APi-TOF as adducts with the artificially introduced primary ion (NO3-). For the first time, we identified several clusters containing up to 40 carbon atoms. These ions are formed by up to four oxidised α-pinene units clustered with NO3-. While we know that dimers (16-20 carbon atoms) are probably formed by a covalent bond between two α-pinene oxidised units, it is still unclear what bonding formed larger clusters. Finally, diurnal profiles of the negative ions were consistent with the neutral compounds revealing that ONs peak during the day while HOMs are more abundant at night-time. However, during the day, a large fraction of the negative charge is taken up by the pure sulfuric acid clusters causing differences between ambient ions and neutral

  15. The evaluation stage of the Hoeven Outcome Monitor (HOM): Towards an evidence based groundwork in forensic mental health.

    Science.gov (United States)

    Keune, Lobke H; de Vogel, Vivienne; van Marle, Hjalmar J C

    This study examined if a macro-, meso-, and micro outcome measurement instrument that constitutes the evaluation stage of a Dutch forensic psychiatric outcome monitor, the Hoeven Outcome Monitor (HOM), can provide a first step towards a more evidence based groundwork in forensic mental health. General, serious, very serious, special, and tbs meriting recidivism during treatment, after treatment, and overall were charted for forensic psychiatric patients discharged from a Dutch forensic psychiatric centre between 1999 and 2008 (N=164). Re-conviction data were obtained from the official Criminal Records System, and the mean follow-up time was 116.2months. First, the results showed that the macro-measurements provide comparative outcome measures to generate insight into the overall effectiveness of forensic psychiatric treatment. Second, the meso-measurements yielded clinically relevant treatment outcome data for all discharged patients to generate a complete view of treatment effectiveness. Finally, the micro-measurements allowed access to detailed patient and treatment effectiveness assessments that provides the empirical foundation to conduct aetiological research into the prediction and control of high-risk behaviour. Thus, an outcome measurement instrument in line with Evidence Based Medicine and best practice guidelines was designed that provides an empirically sound evaluation framework for treatment effectiveness, and an impetus for the development of effective interventions to generate an evidence based groundwork in forensic mental health. Copyright © 2017. Published by Elsevier Ltd.

  16. Multipactor simulations in superconducting cavities and power couplers

    Directory of Open Access Journals (Sweden)

    G. Devanz

    2001-01-01

    Full Text Available A new computer code for simulation of multipacting phenomenon in axisymmetrical radio frequency structures is presented. The existence of resonant electron trajectories can lead to electron multiplication under given field and surface conditions and can damage these accelerator components or prevent their use. The goal of the simulation is to detect such occurrences. Therefore, large parameter sets have to be tested; a parallel version of the code has been developed to reduce computing time while dealing with highly demanding cases in terms of accuracy and parameter sweeping. Both superconducting cavities and power coupler components have been studied. Simulation results are compared with experimental measurements.

  17. Characteristic calculation of directional coupler for accelerator high-power feeders

    CERN Document Server

    Egorov, M A; Kaminsky, V I; Sobenin, N P; Zavadtsev, A A

    2001-01-01

    The calculation results of directional couplers with connection via the waveguide common narrow wall a coupling factor of 3.0 decibels,directivity no less than 20 decibels,adjustment of coupling factor at +- 1 decibels are presented. The adjustment is carried out with the help of cylindrical plungers, moving inside of waveguides on the part of broad walls in the location of the connection slot,and prismatic plungers,moving in rectangular waveguides connected to narrow walls opposite to a slot of connection. The device as a magic tee with movable throttle pistons in E- and H-plane arms permitting to match any load is designed too. The calculations are executed for devices operating at frequencies of 2.797 and 1.3 GHz.

  18. Direct laser written polymer waveguides with out of plane couplers for optical chips

    Directory of Open Access Journals (Sweden)

    Alexander Landowski

    2017-10-01

    Full Text Available Optical technologies call for waveguide networks featuring high integration densities, low losses, and simple operation. Here, we present polymer waveguides fabricated from a negative tone photoresist via two-photon-lithography in direct laser writing, and show a detailed parameter study of their performance. Specifically, we produce waveguides featuring bend radii down to 40 μm, insertion losses of the order of 10  dB, and loss coefficients smaller than 0.81 dB mm−1, facilitating high integration densities in writing fields of 300 μm×300 μm. A novel three-dimensional coupler design allows for coupling control as well as direct observation of outputs in a single field of view through a microscope objective. Finally, we present beam-splitting devices to construct larger optical networks, and we show that the waveguide material is compatible with the integration of quantum emitters.

  19. Two-channel highly sensitive sensors based on 4 × 4 multimode interference couplers

    Science.gov (United States)

    Le, Trung-Thanh

    2017-12-01

    We propose a new kind of microring resonators (MRR) based on 4 × 4 multimode interference (MMI) couplers for multichannel and highly sensitive chemical and biological sensors. The proposed sensor structure has advantages of compactness and high sensitivity compared with the reported sensing structures. By using the transfer matrix method (TMM) and numerical simulations, the designs of the sensor based on silicon waveguides are optimized and demonstrated in detail. We apply our structure to detect glucose and ethanol concentrations simultaneously. A high sensitivity of 9000 nm/RIU, detection limit of 2 × 10‒4 for glucose sensing and sensitivity of 6000 nm/RIU, detection limit of 1.3 × 10‒5 for ethanol sensing are achieved.

  20. Performance analysis and material dependence of micro holographic optical elements as couplers for fiber optic communication

    Science.gov (United States)

    Ambadiyil, Sajan; Prasannan, G.; Sathyan, Jithesh; Ajith Kumar, P. T.

    2005-01-01

    Holographic Optical Elements (HOEs) are gaining much importance and finding newer and better applications in areas of optical fiber communication and optical information processing systems. In contrast to conventional HOEs, optical communication and information systems require smaller and efficient elements of desired characteristics and transfer functions. Such Micro Holographic Optical Elements (MHOEs) can either be an HOE, recorded with two narrow beams of laser light or a segment cut from a larger HOE (SHOEs), and recorded in the conventional manner. In this study, micro holographic couplers, having specific focusing and diffraction characteristics were recorded in different holographic recording media such as silver halide and dichromated gelatin. Wavelength response of the elements was tested at 633 nm and 442 nm. Variation in diffraction efficiency/coupling factor, and insertion loss of the elements were studied. The paper reports in detail about the above results and related design considerations.

  1. An Efficient Large-Area Grating Coupler for Surface Plasmon Polaritons

    CERN Document Server

    Koev, Stephan T; Lezec, Henri J; Aksyuk, Vladimir A

    2011-01-01

    We report the design, fabrication and characterization of a periodic grating of shallow rectangular grooves in a metallic film with the goal of maximizing the coupling efficiency of an extended plane wave (PW) of visible or near-infrared light into a single surface plasmon polariton (SPP) mode on a flat metal surface. A PW-to-SPP power conversion factor > 45 % is demonstrated at a wavelength of 780 nm, which exceeds by an order of magnitude the experimental performance of SPP grating couplers reported to date at any wavelength. Conversion efficiency is maximized by matching the dissipative SPP losses along the grating surface to the local coupling strength. This critical coupling condition is experimentally achieved by tailoring the groove depth and width using a focused ion beam.

  2. Untersuchungen zur Cholesterin-Homöostase in Telomerase-immortalisierten Tangier-Fibroblasten

    OpenAIRE

    Niehaus, Julia

    2006-01-01

    In dieser Arbeit wurde die zelluläre Cholesterin-Homöostase in menschlichen Zellen von Patienten mit der seltenen Tangier-Erbkrankheit (TD) untersucht. Diese Patienten besitzen verschiedene Mutationen im ABCA1-Gen, welches eine zentrale Rolle im Cholesterin-Export spielt, und haben aufgrund des niedrigen bzw. fehlenden HDL im Plasma ein erhöhtes Risiko, kardiovaskuläre Erkrankungen auszuprägen. Es ist jedoch unklar, wieso es trotz der relativ einheitlichen HDL-Defizienz zu völlig unterschiedl...

  3. Determinantes de la variabilidad de los dientes en homínidos

    OpenAIRE

    Bermúdez de Castro, José María

    1995-01-01

    [ES] Las actuales investigaciones en biología del desarrollo permiten avanzar en la discusión y contrastacián de las diferentes teorías propuestas para explicar la variabilidad cuantitativa y cualitativa de los dientes en homínidos. Así, se puede proponer un modelo sintético en el que se consideran tres niveles de determinación de la morfología y dimensiones de los dientes, caracterizados por diferenies factores genéticos, epigenéticos y de stress ambiental. Este modelo contemp...

  4. Higher order modes HOMs in coupled cavities of the FLASH module ACC39

    CERN Document Server

    Shinton, I R R; Li, Z; Zhang, P

    2011-01-01

    We analyse the higher order modes (HOM’s) in the 3.9GHz bunch shaping cavities installed in the FLASH facility at DESY. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations (GSM) are used to investigate the modes in these cavities. This study is primarily focused on the dipole component of the multiband expansion of the wakefield, with the emphasis being on the development of a HOM-based BPM system for ACC39. Coupled inter-cavity modes are simulated together with a limited band of trapped modes.

  5. Capacitive-mesh output couplers for optically pumped far-infrared lasers.

    Science.gov (United States)

    Weitz, D A; Skocpol, W J

    1978-07-01

    The use of capacitive-mesh output couplers for optically pumped far-infrared molecular lasers has been extended throughout the far-infrared spectrum, between 42 microm and 1.2 mm, and the optimum grid constants have been found for several lines. At shorter wavelengths, performance has been improved by the use of a novel hybrid capacitive-mesh hole output coupler.

  6. Optical nano-antennae as compact and efficient couplers from free-space to waveguide modes

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Zenin, Volodymyr; Malureanu, Radu

    2015-01-01

    Optical nano-antennae are one of the possible solutions for coupling free-space radiation into subwavelength waveguides. Other possibilities include, among others, grating couplers and end-fire end couplers. Our efforts were concentrated on nano-antennae used for coupling IR light in the telecom ...

  7. Finite element analysis and frequency shift studies for the bridge coupler of the coupled cavity linear accelerator of the spallation neutron source.

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z. (Zukun)

    2001-01-01

    The Spallation Neutron Source (SNS) is an accelerator-based neutron scattering research facility. The linear accelerator (linac) is the principal accelerating structure and divided into a room-temperature linac and a superconducting linac. The normal conducting linac system that consists of a Drift Tube Linac (DTL) and a Coupled Cavity Linac (CCL) is to be built by Los Alamos National Laboratory. The CCL structure is 55.36-meters long. It accelerates H- beam from 86.8 Mev to 185.6 Mev at operating frequency of 805 MHz. This side coupled cavity structure has 8 cells per segment, 12 segments and 11 bridge couplers per module, and 4 modules total. A 5-MW klystron powers each module. The number 3 and number 9 bridge coupler of each module are connected to the 5-MW RF power supply. The bridge coupler with length of 2.5 {beta}{gamma} is a three-cell structure and located between the segments and allows power flow through the module. The center cell of each bridge coupler is excited during normal operation. To obtain a uniform electromagnetic filed and meet the resonant frequency shift, the RF induced heat must be removed. Thus, the thermal deformation and frequency shift studies are performed via numerical simulations in order to have an appropriate cooling design and predict the frequency shift under operation. The center cell of the bridge coupler also contains a large 4-inch slug tuner and a tuning post that used to provide bulk frequency adjustment and field intensity adjustment, so that produce the proper total field distribution in the module assembly.

  8. Preventing distortion of quick couplers of hoses of central pipe lines--a cheap and simple method.

    Directory of Open Access Journals (Sweden)

    Kamath S

    1995-01-01

    Full Text Available A cheap and practical approach of steel chains attached to the station outlet quick couplers helps in maintaining the shape of the quick couplers and ensures their effective functioning over a long period of time and avoids mishap of connection due to damage of these couplers.

  9. Silicon nitride tri-layer vertical Y-junction and 3D couplers with arbitrary splitting ratio for photonic integrated circuits.

    Science.gov (United States)

    Shang, Kuanping; Pathak, Shibnath; Liu, Guangyao; Feng, Shaoqi; Li, Siwei; Lai, Weicheng; Yoo, S J B

    2017-05-01

    We designed and demonstrated a tri-layer Si3N4/SiO2 photonic integrated circuit capable of vertical interlayer coupling with arbitrary splitting ratios. Based on this multilayer photonic integrated circuit platform with each layer thicknesses of 150 nm, 50 nm, and 150 nm, we designed and simulated the vertical Y-junctions and 3D couplers with arbitrary power splitting ratios between 1:10 and 10:1 and with negligible(< -50 dB) reflection. Based on the design, we fabricated and demonstrated tri-layer vertical Y-junctions with the splitting ratios of 1:1 and 3:2 with excess optical losses of 0.230 dB. Further, we fabricated and demonstrated the 1 × 3 3D couplers with the splitting ratio of 1:1:4 for symmetric structures and variable splitting ratio for asymmetric structures.

  10. Nonsymmetric AlGaN directional coupler switch analysis

    Science.gov (United States)

    Crespo, Antonio; Karim, Mohammad A.

    1998-11-01

    AlGaN has been in the spotlight lately for its use in blue to UV lasers and LEDs, tolerances to high temperature/harsh environment, high power applications, etc. Little has been examined in the area of electro-optic (EO) modulation and waveguiding. This paper compiles the optical and EO properties of AlGaN. It also models the behavior of AlGaN integrated optic waveguides and switches based on the zero- gap EO directional coupler. Among the advantages of AlGaN integrated optic waveguides and switches is the potential to work at wavelengths for IR to the blue region. Additionally, GaN has a close refractive index match, to glass and polymer optical fibers and waveguides. Preliminary findings suggest that the size of AlGaN EO directional couplers, based on measured nonlinear properties of the material and, assuming a viable PIN structure, could be in the range of approximately 7000 micrometers , operating at TTL voltages, with potentially high modulation switching speeds.

  11. Graphene-based terahertz tunable plasmonic directional coupler

    Energy Technology Data Exchange (ETDEWEB)

    He, Meng-Dong, E-mail: hemendong@sohu.com; Wang, Kai-Jun; Wang, Lei; Li, Jian-Bo [Institute of Mathematics and Physics, Central South University of Forestry and Technology, Changsha 410004 (China); Liu, Jian-Qiang [College of Science, Jiujiang University, Jiujiang 332005 (China); Huang, Zhen-Rong; Wang, Lingling [Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, Hunan University, Changsha 410082 (China); Wang, Lin; Hu, Wei-Da; Chen, Xiaoshuang [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083 (China)

    2014-08-25

    We propose and numerically analyze a terahertz tunable plasmonic directional coupler which is composed of a thin metal film with a nanoscale slit, dielectric grating, a graphene sheet, and a dielectric substrate. The slit is employed to generate surface plasmon polaritons (SPPs), and the metal-dielectric grating-graphene-dielectric constructs a Bragg reflector, whose bandgap can be tuned over a wide frequency range by a small change in the Fermi energy level of graphene. As a graphene-based Bragg reflector is formed on one side of the slit, the structure enables SPP waves to be unidirectionally excited on the other side of the slit due to SPP interference, and the SPP waves in the Bragg reflector can be efficiently switched on and off by tuning the graphene's Fermi energy level. By introducing two optimized graphene-based Bragg reflectors into opposite sides of the slit, SPP waves can be guided to different Bragg reflectors at different Fermi energy levels, thus achieving a tunable bidirectional coupler.

  12. Measurement of beam phase at FLASH using HOMs in accelerating cavities

    CERN Document Server

    Shi, Lianliang; Jones, Roger M; Joshi, Nirav

    2017-01-01

    The beam phase relative to the accelerating field is of vital importance for the quality of photon beams produced in modern Free Electron Lasers based on superconducting cavities. Normally, the phase is determined by detecting the transient field induced by the beam. In this way the phase of each cavity is checked and adjusted typically every few months. In this paper, we present an on-line method of beam phase determination, based on higher order modes (HOMs) excited in the 2nd monopole band by the beam inside these cavities. A circuit model of this HOM band is also presented. Various effects on the resolution have been studied. The results indicate that the resolution is strongly dependent on the signal to noise ratio and the sampling rate. Preliminary experimental results, based on a broadband setup, reveal a resolution of ca. 0.1° RMS. These are in good agreement with simulation results. The work will pave the way for a dedicated system of beam phase monitoring, which is under development for the Europea...

  13. Homologous expression of aspartokinase (ask) gene in Streptomyces clavuligerus and its hom-deleted mutant

    Science.gov (United States)

    Okay, Sezer; Ünsaldı, Eser; Taşkın, Bilgin; Liras, Paloma; Piret, Jacqueline

    2010-01-01

    In this study, the effect of homologous multiple copies of the ask gene, which encodes aspartokinase catalyzing the first step of the aspartate pathway, on cephamycin C biosynthesis in S. clavuligerus NRRL 3585 and its hom mutant was investigated. The intracellular pool levels of aspartate pathway amino acids accorded well with the Ask activity levels in TB3585 and AK39. When compared with the control strain carrying vector alone without any gene insert, amplification of the ask gene in the wild strain resulted in a maximum of 3.1- and 3.3-fold increase in specific, 1.7- and 1.9-fold increase in volumetric cephamycin C production when grown in trypticase soy broth (TSB) and a modified chemically defined medium (mCDM), respectively. However, expression of multicopy ask gene in a hom-deleted background significantly decreased cephamycin C yields when the cells were grown in either TSB or mCDM, most probably due to physiological disturbance resulting from enzyme overexpression and high copy number plasmid burden in an auxotrophic host, respectively. PMID:21326925

  14. A Novel Ku-Band/Ka-Band and Ka-Band/E-Band Multimode Waveguide Couplers for Power Measurement of Traveling-Wave Tube Amplifier Harmonic Frequencies

    Science.gov (United States)

    Wintucky, Edwin G.; Simons, Rainee N.

    2015-01-01

    This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler, fabricated from two dissimilar frequency band waveguides, is capable of isolating power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT) amplifier. Test results from proof-of-concept demonstrations are presented for a Ku-band/Ka-band MDC and a Ka-band/E-band MDC. In addition to power measurements at harmonic frequencies, a potential application of the MDC is in the design of a satellite borne beacon source for atmospheric propagation studies at millimeter-wave (mm-wave) frequencies (Ka-band and E-band).

  15. Relaxed tolerance adiabatic silicon coupler for high I/O port-density optical interconnects (Conference Presentation)

    Science.gov (United States)

    Fard, Erfan; Norwood, Robert A.; Peyghambarian, Nasser N.; Koch, Thomas L.

    2017-02-01

    Widespread deployment of silicon photonics will benefit strongly from improved high-port-density interconnect solutions between chips, interposers, and other waveguide fabrics. We present an adiabatic silicon waveguide to polymer waveguide coupler design incorporating strong vertical asymmetries offering high efficiency, small footprint, and improved tolerance to lateral misalignment. The design incorporates a standard 450nm-wide silicon waveguide tapered down to 50nm over a distance of 200μm with a 1.6μm-thick polymer waveguide having a 4μm-wide core atop the taper. The coupler exhibits design should enable reduction in manufacturing costs due to a reduced on-chip footprint and the potential for lower-precision, higher-throughput assembly tools. The authors would like to acknowledge the support of AIM Photonics. This material is based on research sponsored by Air Force Research Laboratory under agreement number FA8650-15-2-5220. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of Air Force Research Laboratory or the U.S. Government.

  16. Development of photonic-crystal-fiber-based optical coupler with a broad operating wavelength range of 800 nm

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Min-Seok; Kwon, Oh-Jang; Kim, Hyun-Joo; Chu, Su-Ho; Kim, Gil-Hwan; Lee, Sang-Bae; Han, Young-Geun [Hanyang University, Seoul (Korea, Republic of)

    2010-12-15

    We developed a broadband optical coupler based on a photonic crystal fiber (PCF), which is very useful for applications to optical coherence tomography (OCT). The PCF-based coupler is fabricated by using a fused biconical tapering (FBT) method. The PCF has six hexagonally-stacked layers of air holes. The PCF-based coupler has a nearly-flat 50/50 coupling ratio in a broad bandwidth range of 800 nm, which is much wider than that previously reported for a PCF-based coupler and a singlemode-fiber-based coupler. The bandwidth and the bandedge wavelength of the broadband coupler are controlled by changing the elongation length. The fabricated broadband optical coupler has great potential for realizing a broadband interferogram with a high resolution in an OCT system.

  17. Hybrid fiber resonator employing LRSPP waveguide coupler for gyroscope.

    Science.gov (United States)

    Qian, Guang; Fu, Xing-Chang; Zhang, Li-Jiang; Tang, Jie; Liu, Yi-Ran; Zhang, Xiao-Yang; Zhang, Tong

    2017-01-24

    Polarization error and temperature noise are two main limits to the performance of resonant fiber optic gyroscope (RFOG). To overcome these limits, we demonstrated a hybrid resonator consisting of a polymer-based long-range surface plasmon polariton (LRSPP) waveguide coupler and a silica fiber. Single-polarization property of LRSPP waveguide and the offsetting of the opposite thermo-optical characteristics between the polymer-based LRSPP waveguide and the silica fiber can effectively inhibit both the polarization error and the temperature noise of RFOG. The measured resonance spectrum of the hybrid resonator shows the absence of polarization noise. The temperature dependence of wavelength shift (TDWS) of resonator dropped to about 2 pm/°C, or even to 0 pm/°C with optimal structure, which dramatically improves the temperature stability of gyroscope system. In addition, the hybrid resonator also shows tremendous application potential in rate-grade and tactical-grade gyroscopes.

  18. HF power couplers for pulsed superconducting cavity resonators; Coupleurs de puissance HF pour cavites supraconductrices en mode pulse

    Energy Technology Data Exchange (ETDEWEB)

    Jenhani, Hassen [Laboratoire de l' Accelerateur Lineaire, IN2P3-CNRS et Universite de Paris-Sud, BP 34, F-91898 Orsay Cedex (France)

    2006-11-15

    Recent years have seen an impressive improvement in the accelerating gradients obtained in superconducting cavities. Consequently, such cavities have become attractive candidates for large superconducting linear accelerator projects such as the European XFEL and the International Linear Collider (ILC). As a result, there is a strong interest in reducing RF conditioning time and improving the performance of the input power couplers for these cavities. The so-called TTF-III input power coupler, adopted for the XFEL superconducting RF cavities are complex components. In order to better understand the behavior of this component we have performed a series of experiments on a number of such couplers. Initially, we developed a fully automated RF high power test stand for coupler conditioning procedure. Following this, we performed a series of coupler conditioning tests. This has allowed the study of the coupler behavior during processing. A number of experiments were carried out to evaluate the in-situ baking effect on the conditioning time. Some of the conditioned couplers were sent to DESY in order to be tested on 9-cells TESLA cavities under cryogenic conditions. These tests have shown that the couplers in no way limit the cavity performance, even up to gradients of 35 MV/m. The main objective of our coupler studies was the reduction of their conditioning time, which represents one of the most important criteria in the choice of coupler for high energy linacs. Excellent progress in reducing the conditioning time has been demonstrated by making appropriate modifications to the conditioning procedure. Furthermore, special attention was paid to electron generation processes in the couplers, via multipacting. Simulations of this process were made on both the TTF-III coupler and on a new coupler prototype, TTF-V. Experiments aimed at suppressing multipacting were also successfully achieved by using a DC bias on the inner conductor of the co-axial coupler. (author)

  19. Compound Josephson-junction coupler for flux qubits with minimal crosstalk

    Science.gov (United States)

    Harris, R.; Lanting, T.; Berkley, A. J.; Johansson, J.; Johnson, M. W.; Bunyk, P.; Ladizinsky, E.; Ladizinsky, N.; Oh, T.; Han, S.

    2009-08-01

    An improved tunable coupling element for building networks of coupled rf-superconducting quantum interference device (rf-SQUID) flux qubits has been experimentally demonstrated. This new form of coupler, based on the compound Josephson-junction rf-SQUID, provides a sign and magnitude tunable mutual inductance between qubits with minimal nonlinear crosstalk from the coupler tuning parameter into the qubits. Quantitative agreement is shown between an effective one-dimensional model of the coupler’s potential and measurements of the coupler persistent current and susceptibility.

  20. Q-switching an all-fiber laser using acousto-optic null coupler

    Science.gov (United States)

    Berg, Yuval; Goldring, Sharone; Pearl, Shaul; Arie, Ady

    2013-05-01

    A new method for Q-switching an all-fiber laser is presented. It is based on induced acoustic long period grating operating on a null coupler, which acts as acoustically controlled tunable output coupler. Q-switching is achieved by switching on and off the acoustic wave in a burst mode, thereby generating laser pulses that are ~400 times shorter than the acoustically controlled coupler's rise time. Output pulse energy of 22 μJ and temporal width of ~100 ns were measured at a wavelength of 1.54 μm.

  1. Raman probes based on optically-poled double-clad fiber and coupler

    DEFF Research Database (Denmark)

    Brunetti, Anna Chiara; Margulis, Walter; Rottwitt, Karsten

    2012-01-01

    Two fiber Raman probes are presented, one based on an optically-poled double-clad fiber and the second based on an optically-poled double-clad fiber coupler respectively. Optical poling of the core of the fiber allows for the generation of enough 532nm light to perform Raman spectroscopy...... of a sample of dimethyl sulfoxide (DMSO), when illuminating the waveguide with 1064nm laser light. The Raman signal is collected in the inner cladding, from which it is retrieved with either a bulk dichroic mirror or a double-clad fiber coupler. The coupler allows for a substantial reduction of the fiber...

  2. Further Clarifying Proximal Withdrawal States and the Turnover Criterion Space: Comment on Hom, Mitchell, Lee, and Griffeth (2012)

    Science.gov (United States)

    Maertz, Carl P., Jr.

    2012-01-01

    In "Reviewing Employee Turnover: Focusing on Proximal Withdrawal States and an Expanded Criterion," Hom, Mitchell, Lee, and Griffeth (2012) brought together many of the most important content and process factors in the employee turnover literature. In this paper, I attempt to clarify the true contributions of this framework for the turnover area…

  3. Changes in antioxidant and fruit quality in hot water-treated ‘Hom Thong’ banana fruit during storage

    Science.gov (United States)

    The effects of hot water treatment on antioxidant phytochemicals and fruit quality were investigated in banana fruit of cv. Gros Michel (Musa acuminata, AAA Group, locally called cv. Hom Thong) by immersing fruits in hot water (50 'C) for 10 min, before storage at 25 'C for 10 days or 14 'C for 8 da...

  4. Demonstration of a High-Order Mode Input Coupler for a 220-GHz Confocal Gyrotron Traveling Wave Tube

    Science.gov (United States)

    Guan, Xiaotong; Fu, Wenjie; Yan, Yang

    2018-02-01

    A design of high-order mode input coupler for 220-GHz confocal gyrotron travelling wave tube is proposed, simulated, and demonstrated by experimental tests. This input coupler is designed to excite confocal TE 06 mode from rectangle waveguide TE 10 mode over a broadband frequency range. Simulation results predict that the optimized conversion loss is about 2.72 dB with a mode purity excess of 99%. Considering of the gyrotron interaction theory, an effective bandwidth of 5 GHz is obtained, in which the beam-wave coupling efficiency is higher than half of maximum. The field pattern under low power demonstrates that TE 06 mode is successfully excited in confocal waveguide at 220 GHz. Cold test results from the vector network analyzer perform good agreements with simulation results. Both simulation and experimental results illustrate that the reflection at input port S11 is sensitive to the perpendicular separation of two mirrors. It provides an engineering possibility for estimating the assembly precision.

  5. Rapid assessment of mid-infrared refractive index anisotropy using a prism coupler: chemical vapor deposited ZnS.

    Science.gov (United States)

    Qiao, H A; Lipschultz, Kristen A; Anheier, N C; McCloy, J S

    2012-05-01

    A state-of-the-art mid-infrared prism coupler was used to study suspected anisotropy in the refractive index of forward-looking-infrared grade chemical vapor deposited (CVD) zinc sulfide. Samples were prepared with columnar grain structure in and perpendicular to the sample plane, as well as from different depths in the CVD growth body. This study was motivated by the growing industry concern among optical design engineers, as well as developers of mid-infrared systems, over the reliability of historically accepted index data. Prior photoluminescence and x-ray diffraction measurements have suggested that refractive index may vary according to sample orientation with respect to the grain structure. Measurements were conducted to provide optical dispersion and thermal index (dn/dT) data at discrete laser wavelengths between 0.633 and 10.591 μm at two temperature set points (30 °C and 90 °C). Refractive index measurements between samples exhibited an average standard deviation comparable to the uncertainty of the prism coupler measurement (0.0004 refractive index units), suggesting that the variation in refractive index as a function of sample orientation and CVD deposition time is negligible and should have no impact on subsequent optical designs. Measured dispersion data at mid-infrared wavelengths were also found to agree well with prior published measurements.

  6. L'hepcidine, le chef d'orchestre de l'homéostasie du fer

    OpenAIRE

    Nicolas, Gaël

    2009-01-01

    Dans un organisme en bonne santé le fer est en mouvement permanent entre les sites où il est absorbé (le duodénum), où il est utilisé (principalement la moelle osseuse) et où il est stocké (le foie et la rate). L'homéostasie de ces mouvements de fer repose sur le contrôle strict de plusieurs paramètres tels que l'absorption intestinale du fer, son utilisation pour l'érythropoïèse, le recyclage du fer à partir des globules rouges défecteux ou en fin de vie et enfin la bonne gestion des stocks ...

  7. leeHom: adaptor trimming and merging for Illumina sequencing reads.

    Science.gov (United States)

    Renaud, Gabriel; Stenzel, Udo; Kelso, Janet

    2014-10-01

    The sequencing of libraries containing molecules shorter than the read length, such as in ancient or forensic applications, may result in the production of reads that include the adaptor, and in paired reads that overlap one another. Challenges for the processing of such reads are the accurate identification of the adaptor sequence and accurate reconstruction of the original sequence most likely to have given rise to the observed read(s). We introduce an algorithm that removes the adaptors and reconstructs the original DNA sequences using a Bayesian maximum a posteriori probability approach. Our algorithm is faster, and provides a more accurate reconstruction of the original sequence for both simulated and ancient DNA data sets, than other approaches. leeHom is released under the GPLv3 and is freely available from: https://bioinf.eva.mpg.de/leehom/ © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  8. Homéostasie cellulaire chez Saccharomyces cerevisiae : Etude des effets des acides faibles.

    OpenAIRE

    FAURE, Lætitia

    2005-01-01

    L’étude de l’homéostasie cellulaire chez Saccharomyces cerevisiae dans la réponse à un stress imposé par un acide faible repose sur l’analyse cinétique de la réponse à des perturbations impulsionnelles réalisées sur des cultures à hautes densités cellulaires pour différents états métaboliques caractérisés par des modes opératoires originaux. Les études différentielles réalisées avec les acides propionique et sorbique montrent que la réponse se caractérise par une séquence évènementielle metta...

  9. El vino de los héroes homéricos

    Directory of Open Access Journals (Sweden)

    Mª José García Soler

    2010-01-01

    Full Text Available El vino tiene un importante papel en el mundo idealizado de los héroes homéricos. El poeta ofrece las primeras descripciones de vinos griegos, principalmente procedentes del norte del Egeo, situándolos en contextos muy variados, como centro del banquete, bebida reconstituyente, elemento imprescindible en plegarias y juramentos e incluso símbolo de honor que distingue a los personajes más destacados.Wine has played an important role in the idealized world of Homeric heroes. The poet made the first descriptions of Greek wines, mainly produced at the North of the Aegean Sea, situating it in a variety of contexts: at the center of a banquet, as a tonic beverage, as an essential element in prayers and oaths, and also as a symbol of the honour that distinguishes themain protagonists.

  10. LHC MD 652: Coupled-Bunch Instability with Smaller Emittance (all HOMs)

    CERN Document Server

    AUTHOR|(CDS)2081238; Timko, Helga; CERN. Geneva. ATS Department

    2017-01-01

    The aim of the MD was to measure the coupled-bunch stability from all HOM impedances, with a reduced longitudinal emittance in order to explore the HL-LHC conditions. The acceleration ramp was performed with the nominal beams of 2016, but a reduced target bunch length and RF voltage. With this reduced emittance, the beam remained close but above the single-bunch stability threshold. No coupled-bunch oscillations were observed, so we can conclude that the stability threshold for coupled-bunch instability is not lower than the single-bunch threshold. An interesting observation in the MD was the long-lasting injection oscillations, whose traces can still be seen at arrival to flat top; in agreement with observations in earlier MDs. The measurements took place between 28th October 20:00 and 29th October 05:10.

  11. Consideration of HOMs in α- and β-pinene SOA model

    Science.gov (United States)

    Gatzsche, Kathrin; Iinuma, Yoshiteru; Mutzel, Anke; Berndt, Torsten; Wolke, Ralf

    2016-04-01

    Secondary organic aerosol (SOA) is the major burden of the atmospheric organic particulate matter with 140 - 910 TgC yr-1 (Hallquist et al., 2009). SOA particles are formed via the oxidation of volatile organic carbons (VOCs), where the volatility of the VOCs is lowered due to the increase in their functionalization as well as their binding ability. Therefore, gaseous compounds can either nucleate to form new particles or condense on existing particles. The framework of SOA formation under natural conditions is very complex, because there are a multitude of gas-phase precursors, atmospheric degradation processes and products after oxidation. A lacking understanding about chemical and physical processes associated with SOA formation makes modeling of SOA processes difficult, leading to discrepancy between measured and modeled global SOA burdens. The present study utilizes a parcel model SPACCIM (SPectral Aerosol Cloud Chemistry Interaction Model, Wolke et al., 2005) that couples a multiphase chemical model with a microphysical model. For SOA modeling a further development of SPACCIM was necessary. Therefore, two components are added (i) a gas-phase chemistry mechanism for the VOC oxidation and (ii) a partitioning approach for the gas-to-particle phase transfer. An aggregated gas-phase chemistry mechanism for α- and β-pinene was adapted from Chen and Griffin (2005). For the phase transfer an absorptive partitioning approach (Pankow, 1994) and a kinetic approach (Zaveri et al., 2014) are implemented. Whereby the kinetic approach serves some advantages. The organic aerosol can be resolved in different size sections, whereby the particle radius is involved in the partitioning equations. The phase state of the organic material and the reactivity of the organic compounds in the particle-phase directly influence the modeled SOA yields. Recently, highly oxidized multifunctional organic compounds (HOMs) were found in the gas phase from lab and field studies. They are also

  12. Esclarecendo o caso dos homônimos Manoel de Abreu

    Directory of Open Access Journals (Sweden)

    Rubens Bedrikow

    2015-09-01

    Full Text Available Recupera-se aqui um episódio curioso da história da medicina brasileira envolvendo dois médicos homônimos nos anos de 1936 e 1937. Manoel Dias de Abreu deixou como seu mais relevante legado um método radiológico para o diagnóstico da tuberculose – a abreugrafia. Manoel de Abreu Campanario escreveu A medicina no interior. A semelhança entre os dois nomes gerou tamanha confusão, que algumas pessoas acreditaram ser Campanario um pseudônimo. Tal engano fez com que Manoel Dias de Abreu encaminhasse uma declaração-consulta à Sociedade de Medicina e Cirurgia, que prontamente criou uma comissão encarregada de examinar o caso. A solução veio com a carta esclarecedora de Campanario.

  13. Fully-etched apodized fiber-to-chip grating coupler on the SOI platform with -0.78 dB coupling efficiency using photonic crystals and bonded Al mirror

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ou, Haiyan; Peucheret, Christophe

    2014-01-01

    We design and fabricate an ultra-high coupling efficiency fully-etched apodized grating coupler on the SOI platform using photonic crystals and bonded aluminum mirror. Ultra-high coupling efficiency of -0.78 dB with a 3 dB bandwidth of 74 nm are demonstrated....

  14. Ultra-low-loss inverted taper coupler for silicon-on-insulator ridge waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    An ultra-low-loss coupler for interfacing a silicon-on-insulator ridge waveguide and a single-mode fiber in both polarizations is presented. The inverted taper coupler, embedded in a polymer waveguide, is optimized for both the transverse-magnetic and transverse-electric modes through tapering...... the width of the silicon-on-insulator waveguide from 450 nm down to less than 15 nm applying a thermal oxidation process. Two inverted taper couplers are integrated with a 3-mm long silicon-on-insulator ridge waveguide in the fabricated sample. The measured coupling losses of the inverted taper coupler...... for transverse-magnetic and transverse-electric modes are ~0.36 dB and ~0.66 dB per connection, respectively....

  15. Estudio del mecanismo de recombinación homóloga en cereales y caracterización de genes implicados en el proceso

    OpenAIRE

    Pérez Vergas, Ruth

    2008-01-01

    En el presente trabajo se han estudiado diferentes aspectos relacionados con los procesos de recombinación homóloga en cereales, concretamente en trigo y cebada. Se pretende así acercarse al objetivo de poder llevar a cabo gene targeting en estas especies de elevado interés agroeconómico. Partiendo del conocimiento de que los procesos de recombinación homóloga son favorecidos tras la rotura de la doble cadena de ADN cuando se encuentran próximas secuencias homólogas (Puchta y col., 1993), se...

  16. Wakefield and RF Kicks Due to Coupler Asymmetry in TESLA-Type Accelerating Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Bane, K.L.F.; Adolphsen, C.; Li, Z.; /SLAC; Dohlus, M.; Zagorodnov, I.; /DESY; Gonin, I.; Lunin, A.; Solyak, N.; Yakovlev, V.; /Fermilab; Gjonaj, E.; Weiland, T.; /Darmstadt, Tech. Hochsch.

    2008-07-07

    In a future linear collider, such as the International Linear Collider (ILC), trains of high current, low emittance bunches will be accelerated in a linac before colliding at the interaction point. Asymmetries in the accelerating cavities of the linac will generate fields that will kick the beam transversely and degrade the beam emittance and thus the collider performance. In the main linac of the ILC, which is filled with TESLA-type superconducting cavities, it is the fundamental (FM) and higher mode (HM) couplers that are asymmetric and thus the source of such kicks. The kicks are of two types: one, due to (the asymmetry in) the fundamental RF fields and the other, due to transverse wakefields that are generated by the beam even when it is on axis. In this report we calculate the strength of these kicks and estimate their effect on the ILC beam. The TESLA cavity comprises nine cells, one HM coupler in the upstream end, and one (identical, though rotated) HM coupler and one FM coupler in the downstream end (for their shapes and location see Figs. 1, 2) [1]. The cavity is 1.1 m long, the iris radius 35 mm, and the coupler beam pipe radius 39 mm. Note that the couplers reach closer to the axis than the irises, down to a distance of 30 mm.

  17. Rapid assessment of mid-infrared refractive index anisotropy using a prism coupler: chemical vapor deposited ZnS

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Hong (Amy); Lipschultz, Kristen A.; Anheier, Norman C.; McCloy, John S.

    2012-04-01

    A state-of-the-art mid-infrared prism coupler was used to study the refractive index properties of forward-looking-infrared (FLIR) grade zinc sulfide samples prepared with unique planar grain orientations and locations with respect to the CVD growth axis. This study was motivated by prior photoluminescence and x-ray diffraction measurements that suggested refractive index may vary according to grain orientation. Measurements were conducted to provide optical dispersion and thermal index (dn/dT) data at discrete laser wavelengths between 0.633 and 10.591 {mu}m at two temperature set points (30 C and 90 C). Refractive index measurements between samples exhibited an average standard deviation comparable to the uncertainty of the prism coupler measurement (0.0004 refractive index units), suggesting that the variation in refractive index as a function of planar grain orientation and CVD deposition time is negligible, and should have no impact on subsequent optical designs. Measured dispersion data at mid-infrared wavelengths was found to agree well with prior published measurements.

  18. Electro-Optic Modulator Based on Organic Planar Waveguide Integrated with Prism Coupler

    Science.gov (United States)

    Sarkisov, Sergey S.

    2002-01-01

    The objectives of the project, as they were formulated in the proposal, are the following: (1) Design and development of novel electro-optic modulator using single crystalline film of highly efficient electro-optic organic material integrated with prism coupler; (2) Experimental characterization of the figures-of-merit of the modulator. It is expected to perform with an extinction ratio of 10 dB at a driving signal of 5 V; (3) Conclusions on feasibility of the modulator as an element of data communication systems of future generations. The accomplishments of the project are the following: (1) The design of the electro-optic modulator based on a single crystalline film of organic material NPP has been explored; (2) The evaluation of the figures-of-merit of the electro-optic modulator has been performed; (3) Based on the results of characterization of the figures-of-merit, the conclusion was made that the modulator based on a thin film of NPP is feasible and has a great potential of being used in optic communication with a modulation bandwidth of up to 100 GHz and a driving voltage of the order of 3 to 5 V.

  19. Birefringent prism couplers for thin-film optical waveguides.

    Science.gov (United States)

    Kurland, I J; Bertoni, H L

    1978-04-01

    The coupling from a laser to a thin-film optical waveguide by a prism coupler composed of a birefringent material can be strongly dependent on the orientation of the optic axis. It is shown that when the effective index of the wave guided by the film lies between the ordinary and extraordinary refractive indices of the prism, the coupling depends strongly on the orientation of the optic axis. Differences in orientation of only a few degrees separate ranges of orientation in which strong coupling occurs from ranges in which there is no coupling. The orientation dependence of the coupling is considered both for the pure mode case wherein the optic axis lies in the plane of incidence and for the case when the optic axis is rotated out of the plane of incidence, so that mode coupling occurs. When the effective refractive index of the guided wave is less than both the ordinary and extraordinary refractive indices of the prism, the coupling properties are found to be similar to those obtained with an isotropic prism.

  20. Surface plasmon resonance prism coupler for enhanced circular dichroism sensing.

    Science.gov (United States)

    Phan, Quoc-Hung; Lo, Yu-Lung; Huang, Chih-Ling

    2016-06-13

    A novel method for enhanced circular dichroism (CD) detection is proposed based on a surface plasmon resonance (SPR) prism coupler and a polarization scanning ellipsometry technique. An analytical model is derived to extract the CD and degree of polarization (DOP) properties of optical samples with and without scattering effects, respectively. The validity of the analytical model is confirmed by means of numerical simulations. The simulation results show that the proposed detection method has a sensitivity of 10-5~10-6 RIU (refractive index unit) for refractive indices in the range of 1.32~1.36 and 1.3100~1.3118. The practical feasibility of the proposed method is demonstrated by the experimental results for the sensitivity of the CD with the chlorophyllin samples with/without scattering effect. It is shown that for both types of sample, the extracted CD value increases linearly with the chlorophyll concentration over the considered range. In general, the results obtained in this study show that the measured CD response is highly sensitive to the polarization scanning angle. Consequently, the potential of polarization scanning ellipsometry for high-resolution CD detection is confirmed.

  1. Investigation of the power coupling of novel wavelength-selective couplers incorporating axially symmetric long-period fibre gratings

    Directory of Open Access Journals (Sweden)

    Johan Burger

    2011-05-01

    Full Text Available Evanescent-field coupling was studied experimentally in novel optical-fibre-based wavelength-selective couplers, using axially symmetric long-period fibre grating (LPFG structures. The coupling characteristics of a wavelength-selective coupler at the resonant wavelength were investigated for different LPFG offset distances. It was shown that the wavelength-selective couplers effectively transferred light power at the LPFG resonant wavelength from one fibre to another. The performance of the couplers was consistent with simulations performed in MATLAB using coupled-mode theory.

  2. Outcomes and reliability of the flow coupler in postoperative monitoring of head and neck free flaps.

    Science.gov (United States)

    Fujiwara, Rance J T; Dibble, Jacqueline M; Larson, Scott V; Pierce, Matthew L; Mehra, Saral

    2017-10-08

    To assess the accuracy and reliability of the flow coupler relative to the implantable arterial Doppler probe in postoperative monitoring of head and neck free flaps. Retrospective single-institution study, April 2015 to March 2017. Both the venous flow coupler and arterial Doppler were employed in 120 consecutive head and neck free flap cases. When Doppler signal loss occurred, flaps were evaluated by physical exam to determine whether signal loss was a true positive necessitating operating room takeback. Sensitivity, specificity, and false positive rate (FPR) were recorded for each device. Logistic regression was conducted to identify user trends over time. Eleven of 120 patients (9.2%) required takeback, 10 from venous thrombosis and one from arterial thrombosis. Permanent signal loss (PSL) occurred in the flow coupler in all takebacks; PSL occurred in the arterial Doppler only in the case of arterial thrombosis. Salvage rate was 9/11 (81.8%). For the flow coupler, sensitivity was 100%, specificity 86.4%, and FPR 13.6%. For the arterial probe, sensitivity was 9.1%, specificity 97.1%, and FPR 2.9%. A 4.1% decrease in false positives with each additional flow coupler use was observed. Monitoring the vein via flow coupler has high sensitivity in identifying vascular compromise compared to the arterial probe, especially for venous thrombosis. There is moderate FPR; this decreases with increased usage and, when supplemented with physical examination, does not result in unnecessary takebacks. The flow coupler can be a valuable tool in postoperative monitoring of head and neck free flaps. 4. Laryngoscope, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  3. Study of a power coupler for superconducting RF cavities used in high intensity proton accelerator; Etude et developpement d'un coupleur de puissance pour les cavites supraconductrices destinees aux accelerateurs de protons de haute intensite

    Energy Technology Data Exchange (ETDEWEB)

    Souli, M

    2007-07-15

    The coaxial power coupler needed for superconducting RF cavities used in the high energy section of the EUROTRANS driver should transmit 150 kW (CW operation) RF power to the protons beam. The calculated RF and dielectric losses in the power coupler (inner and outer conductor, RF window) are relatively high. Consequently, it is necessary to design very carefully the cooling circuits in order to remove the generated heat and to ensure stable and reliable operating conditions for the coupler cavity system. After calculating all type of losses in the power coupler, we have designed and validated the inner conductor cooling circuit using numerical simulations results. We have also designed and optimized the outer conductor cooling circuit by establishing its hydraulic and thermal characteristics. Next, an experiment dedicated to study the thermal interaction between the power coupler and the cavity was successfully performed at CRYOHLAB test facility. The critical heat load Qc for which a strong degradation of the cavity RF performance was measured leading to Q{sub c} in the range 3 W-5 W. The measured heat load will be considered as an upper limit of the residual heat flux at the outer conductor cold extremity. A dedicated test facility was developed and successfully operated for measuring the performance of the outer conductor heat exchanger using supercritical helium as coolant. The test cell used reproduces the realistic thermal boundary conditions of the power coupler mounted on the cavity in the cryo-module. The first experimental results have confirmed the excellent performance of the tested heat exchanger. The maximum residual heat flux measured was 60 mW for a 127 W thermal load. As the RF losses in the coupler are proportional to the incident RF power, we can deduce that the outer conductor heat exchanger performance is continued up to 800 kW RF power. Heat exchanger thermal conductance has been identified using a 2D axisymmetric thermal model by comparing

  4. Operational Data Assimilation in a High Resolution Ocean Model Using the PALM Coupler.

    Science.gov (United States)

    Lellouche, J.; Tranchant, B.; Drillet, Y.; Siefridt, L.; Piacentini, A.

    2001-12-01

    In the framework of the MERCATOR project, a data assimilation system for operational oceanography is being developed. The ocean model (PAM) is based on OPA-8.1, a general circulation model developed at LODYC (Paris), and is designed to simulate the Atlantic and Mediterranean oceans with a very high horizontal resolution (5 to 7 km). The chosen data assimilation method is the optimal interpolation scheme SOFA developed at LEGOS (Toulouse) and implemented in PAM using the PALM coupler developed at CERFACS (Toulouse). The aim is to have a system architecture able to drive the modelling, assimilation and data components together. In this respect, PALM allows the handling of explicit communications between different heterogeneous units such as model and assimilation units, and easier modifications in the data assimilation scheme. The modularity of the coupling will be illustrated by presenting a PALM graphical interface. The prototype system is planned to run in a real time mode in the beginning of 2002. In this context, some assimilation results using altimeter and/or in situ observations will be presented.

  5. Dual-side backward coupler waveguide orthomode transducer for the 3 mm band

    Science.gov (United States)

    Navarrini, Alessandro; Nesti, Renzo

    2008-07-01

    We describe the design, construction, and characterization results of a waveguide Orthomode Transducer (OMT) for the 3 mm band (84-116 GHz.) The OMT is based on a symmetric backward coupling structure and has a square waveguide input port (2.54 mm × 2.54 mm) and two single-mode waveguide outputs: a standard WR10 rectangular waveguide (2.54 mm × 1.27 mm,) and an oval waveguide with full-radius corners. The reverse coupling structure is located in the common square waveguide arm and splits one polarization signal in two opposite rectangular waveguide sidearms using broadband -3 dB E-plane branch-line hybrid couplers. The device was optimized using a commercial 3D electromagnetic simulator. The OMT consists of two mechanical blocks fabricated in split-block configuration using conventional CNC milling machine. From 84 to 116 GHz the measured input reflection coefficient was less than -17 dB, the isolation between the outputs was less than -50 dB, the cross polarization was less than -30 dB, and the transmission was larger than -0.35 dB at room temperature for both polarization channels. The device is suitable for scaling to higher frequency.

  6. Asymmetric adiabatic couplers for fully-integrated broadband quantum-polarization state preparation.

    Science.gov (United States)

    Chung, Hung-Pin; Huang, Kuang-Hsu; Wang, Kai; Yang, Sung-Lin; Yang, Shih-Yuan; Sung, Chun-I; Solntsev, Alexander S; Sukhorukov, Andrey A; Neshev, Dragomir N; Chen, Yen-Hung

    2017-12-04

    Spontaneous parametric down-conversion (SPDC) is a widely used method to generate entangled photons, enabling a range of applications from secure communication to tests of quantum physics. Integrating SPDC on a chip provides interferometric stability, allows to reduce a physical footprint, and opens a pathway to true scalability. However, dealing with different photon polarizations and wavelengths on a chip presents a number of challenging problems. In this work, we demonstrate an on-chip polarization beam-splitter based on z-cut titanium-diffused lithium niobate asymmetric adiabatic couplers (AAC) designed for integration with a type-II SPDC source. Our experimental measurements reveal unique polarization beam-splitting regime with the ability to tune the splitting ratios based on wavelength. In particular, we measured a splitting ratio of 17 dB over broadband regions (>60 nm) for both H- and V-polarized lights and a specific 50%/50% splitting ratio for a cross-polarized photon pair from the AAC. The results show that such a system can be used for preparing different quantum polarization-path states that are controllable by changing the phase-matching conditions in the SPDC over a broad band. Furthermore, we propose a fully integrated electro-optically tunable type-II SPDC polarization-path-entangled state preparation circuit on a single lithium niobate photonic chip.

  7. Magnetic field sensor based on cascaded microfiber coupler with magnetic fluid

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Lianmin; Su, Delong; Wang, Zhaofang [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Pu, Shengli, E-mail: shlpu@usst.edu.cn [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093 (China); Zeng, Xianglong [The Key Lab of Specialty Fiber Optics and Optical Access Network, Shanghai University, Shanghai 200072 (China); Lahoubi, Mahieddine [Laboratory L.P.S., Department of Physics, Faculty of Sciences, Badji-Mokhtar Annaba University, Annaba 23000 (Algeria)

    2016-09-07

    A kind of magnetic field sensor based on cascaded microfiber coupler with magnetic fluid is proposed and experimentally demonstrated. The magnetic fluid is utilized as the cladding of the fused regions of the cascaded microfiber coupler. As the interference valley wavelength of the sensing structure is sensitive to the ambient variation, considering the magnetic-field-dependent refractive index of magnetic fluid, the proposed structure is employed for magnetic field sensing. The effective coupling length for each coupling region of the as-fabricated cascaded microfiber coupler is 6031 μm. The achieved sensitivity is 125 pm/Oe, which is about three times larger than that of the previously similar structure based on the single microfiber coupler. Experimental results indicate that the sensing sensitivity can be easily improved by increasing the effective coupling length or cascading more microfiber couplers. The proposed magnetic field sensor is attractive due to its low cost, immunity to electromagnetic interference, as well as high sensitivity, which also has the potentials in other tunable all-fiber photonic devices, such as filter.

  8. A study of polaritonic transparency in couplers made from excitonic materials

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Mahi R.; Racknor, Chris [Department of Physics and Astronomy, Western University, London, Ontario N6A 3K7 (Canada)

    2015-03-14

    We have studied light matter interaction in quantum dot and exciton-polaritonic coupler hybrid systems. The coupler is made by embedding two slabs of an excitonic material (CdS) into a host excitonic material (ZnO). An ensemble of non-interacting quantum dots is doped in the coupler. The bound exciton polariton states are calculated in the coupler using the transfer matrix method in the presence of the coupling between the external light (photons) and excitons. These bound exciton-polaritons interact with the excitons present in the quantum dots and the coupler is acting as a reservoir. The Schrödinger equation method has been used to calculate the absorption coefficient in quantum dots. It is found that when the distance between two slabs (CdS) is greater than decay length of evanescent waves the absorption spectrum has two peaks and one minimum. The minimum corresponds to a transparent state in the system. However, when the distance between the slabs is smaller than the decay length of evanescent waves, the absorption spectra has three peaks and two transparent states. In other words, one transparent state can be switched to two transparent states when the distance between the two layers is modified. This could be achieved by applying stress and strain fields. It is also found that transparent states can be switched on and off by applying an external control laser field.

  9. Handheld tunable focus confocal microscope utilizing a double-clad fiber coupler for in vivo imaging of oral epithelium

    Science.gov (United States)

    Olsovsky, Cory; Hinsdale, Taylor; Cuenca, Rodrigo; Cheng, Yi-Shing Lisa; Wright, John M.; Rees, Terry D.; Jo, Javier A.; Maitland, Kristen C.

    2017-05-01

    A reflectance confocal endomicroscope with double-clad fiber coupler and electrically tunable focus lens is applied to imaging of the oral mucosa. The instrument is designed to be lightweight and robust for clinical use. The tunable lens allows axial scanning through >250 μm in the epithelium when the probe tip is placed in contact with tissue. Images are acquired at 6.6 frames per second with a field of view diameter up to 850 μm. In vivo imaging of a wide range of normal sites in the oral cavity demonstrates the accessibility of the handheld probe. In vivo imaging of clinical lesions diagnosed as inflammation and dysplasia illustrates the ability of reflectance confocal endomicroscopy to image cellular changes associated with pathology.

  10. Holographic polarization-selective module based on a small dove prism coupler for magneto-optical pickup heads.

    Science.gov (United States)

    Shin, Chang-Won; Vu, Viet-Tien; Kim, Nam; An, Jun-Won; Suh, Dongwoo; Park, Yongwoo; Ryu, Hojun; Paek, Mun-Cheol; Pyo, Hyeon-Bong

    2005-07-10

    A new structure for polarization-selective elements, consisting of two holographic gratings and a Dove prism coupler, is proposed. The absence of a multistage waveguide and the benefits of compact size and lightweight volume are the outstanding features of the new structure. Based on the coupled-wave theory, the analysis and design of the structure are discussed in detail to calculate the required index modulation. Several parameters, such as the recording intensity, the exposure time, and the recording angles for the fabrication of the proposed element, are determined. Under these conditions, the element is fabricated in Dupont photopolymer HRF-150-38 material and with an operating wavelength of 532 nm. A simplified pickup head is constructed to evaluate the performance of the fabricated element.

  11. C-band fundamental/first-order mode converter based on multimode interference coupler on InP substrate

    Science.gov (United States)

    Limeng, Zhang; Dan, Lu; Zhaosong, Li; Biwei, Pan; Lingjuan, Zhao

    2016-12-01

    The design, fabrication and characterization of a fundamental/first-order mode converter based on multimode interference coupler on InP substrate were reported. Detailed optimization of the device parameters were investigated using 3D beam propagation method. In the experiments, the fabricated mode converter realized mode conversion from the fundamental mode to the first-order mode in the wavelength range of 1530-1565 nm with excess loss less than 3 dB. Moreover, LP01 and LP11 fiber modes were successfully excited from a few-mode fiber by using the device. This InP-based mode converter can be a possible candidate for integrated transceivers for future mode-division multiplexing system. Project supported by the National Basic Research Program of China (No. 2014CB340102) and in part by the National Natural Science Foundation of China (Nos. 61274045, 61335009).

  12. Compact two-photon fluorescence microscope based on a single-mode fiber coupler.

    Science.gov (United States)

    Bird, Damian; Gu, Min

    2002-06-15

    We present a two-photon fluorescence microscope based on a three-port single-mode optical fiber coupler. It is found that the coupler behaves as a low-pass filter that can deliver an ultrashort-pulsed laser beam of as much as 150 mW of power in the wavelength range from 770 to 870 nm as well as collect a two-photon fluorescence signal in the visible range. As a result of using the fiber coupler, the new two-photon imaging system exhibts a number of advantages, including a compact arrangement, freedom from vibration from lasers and electronic devices, self-alignment, reduction of multiple scattering, and an enhanced optical sectioning effect. The effectiveness of the new instrument is demonstrated with a set of three-dimensional images of biological samples. This instrument may make two-photon fluorescence endoscopy possible for in vivo medical applications.

  13. Vertical chip-to-chip coupling between silicon photonic integrated circuits using cantilever couplers.

    Science.gov (United States)

    Sun, Peng; Reano, Ronald M

    2011-02-28

    We demonstrate vertical chip-to-chip light coupling using silicon strip waveguide cantilever couplers. The guided-wave couplers consist of silicon strip waveguides embedded within silicon dioxide cantilevers. The cantilevers deflect 90° out-of-plane via residual stress, allowing vertical light coupling between separate chips. A chip-to-chip coupling loss of 2.5 dB per connection is measured for TE polarization and 1.1 dB for TM polarization at 1550 nm wavelength. The coupling loss varies by less than±0.8 dB within the wavelength range from 1500 nm to 1565 nm for both polarizations. The couplers enable broadband and compact system architectures involving high speed vertical data transport between photonic integrated circuits.

  14. All-optical switching using a new photonic crystal directional coupler

    Directory of Open Access Journals (Sweden)

    B. Vakili

    2015-07-01

    Full Text Available In this paper all-optical switching in a new photonic crystal directional coupler is performed.  The structure of the switch consists of a directional coupler and a separate path for a control signal called “control waveguide”. In contrast to the former reported structures in which the directional couplers are made by removing a row of rods entirely, the directional coupler in our optical switch is constructed by two reduced-radius line-defect waveguides separated by the control waveguide. Furthermore, in our case the background material has the nonlinear Kerr property. Therefore, in the structure of this work, no frequency overlap occurs between the control waveguide mode and the directional coupler modes. It is shown that such a condition provides a very good isolation between the control and the probe signals at the output ports. In the control waveguide, nonlinear Kerr effect causes the required refractive index change by the presence of a high power control (pump signal. Even and odd modes of the coupler are investigated by applying the distribution of the refractive index change in the nonlinear region of a super-cell so that a switching length of about 94 µm is obtained at the wavelength of 1.55 µm. Finally, all-optical switching of the 1.55 µm probe signal using a control signal at the wavelength of 1.3 µm, is simulated through the finite-difference time-domain method, where both signals are desirable in optical communication systems. A very high extinction ratio of 67 dB is achieved and the temporal characteristics of the switch are demonstrated.

  15. On-chip Mode Multiplexer Based on a Single Grating Coupler

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ou, Haiyan; Xu, Jing

    2012-01-01

    A two-mode multiplexer based on a single grating coupler is proposed and demonstrated on a silicon chip. The LP01 and LP11 modes of a few-mode fiber are excited from TE0 and TE1 silicon waveguide modes.......A two-mode multiplexer based on a single grating coupler is proposed and demonstrated on a silicon chip. The LP01 and LP11 modes of a few-mode fiber are excited from TE0 and TE1 silicon waveguide modes....

  16. Ultra-High-Efficiency Apodized Grating Coupler Using a Fully Etched Photonic Crystal

    DEFF Research Database (Denmark)

    Ding, Yunhong; Peucheret, Christophe; Ou, Haiyan

    2013-01-01

    We demonstrate an apodized fiber-to-chip grating coupler using fully etched photonic crystal holes on the silicon-on-insulator platform. An ultra-high coupling efficiency of 1.65 dB (68%) with 3 dB bandwidth of 60 nm is experimentally demonstrated.......We demonstrate an apodized fiber-to-chip grating coupler using fully etched photonic crystal holes on the silicon-on-insulator platform. An ultra-high coupling efficiency of 1.65 dB (68%) with 3 dB bandwidth of 60 nm is experimentally demonstrated....

  17. Análisis de audiencias : estudio comparativo de medios con respecto a sus homólogos digitales

    OpenAIRE

    Cea Esteruelas, Nereida

    2014-01-01

    El artículo examina la audiencia de distintos medios de comunicación (prensa, radio y televisión), comparándola con el número de usuarios y pautas de consumo que presentan sus homólogos en Internet. Los resultados se obtienen mediante un análisis empírico de los principales indicadores que ofrece la audimetría de medios. El análisis de los datos recabados en este estudio permite concluir que, con respecto a la prensa, las ediciones digitales de los periódicos más leídos superan...

  18. Computer Determination of HOM Damping for a Prototype JLC Accelerator Cavity and a Prototype B Factory Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Kroll, N.

    2005-04-08

    In this paper the authors describe the determination of the properties of the above referenced cavities with particular emphasis on the damping of the higher order modes (HOM). Because mode frequency spectra were determined for a large number of shorted waveguide lengths, rather complete analyses are possible. Phase frequency plots have proved to be an invaluable aid in sorting out overlapping resonances and separating cavity resonances from waveguide resonances. Algorithms for the determination of the parameters of several resonances simultaneously have been developed. Determinations of Q from multiresonance analyses are compared to those from single resonance analyses, and the changes are typically found to be small.

  19. Redesign of the End Group in the 3.9 GHz LCLS-II Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Lunin, Andrei [Fermilab; Gonin, Ivan [Fermilab; Khabiboulline, Timergali [Fermilab; Solyak, Nikolay [Fermilab

    2017-05-01

    Development and production of Linac Coherent Light Source II (LCLS-II) is underway. The central part of LCLS-II is a continuous wave superconducting RF (CW SCRF) electron linac. The 3.9 GHz third harmonic cavity similar to the XFEL design will be used in LCLS-II for linearizing the longitudinal beam profile*. The initial design of the 3.9 GHz cavity developed for XFEL project has a large, 40 mm, beam pipe aperture for better higher-order mode (HOM) damping. It is resulted in dipole HOMs with frequencies nearby the operating mode, which causes difficulties with HOM coupler notch filter tuning. The CW linac operation requires an extra caution in the design of the HOM coupler in order to prevent its possible overheating. In this paper we present the modified 3.9 GHz cavity End Group for meeting the LCLS-II requirements

  20. Final Commissioning of the MICE RF Module Prototype with Production Couplers

    Energy Technology Data Exchange (ETDEWEB)

    Torun, Yagmur [IIT, Chicago; Anderson, Terry [Fermilab; Backfish, Michael [Fermilab; Bowring, Daniel [Fermilab; Freemire, Ben [IIT, Chicago (main); Hart, Terrence [Mississippi U.; Kochemirovskiy, Alexey [Illinois U., Chicago; Lane, Peter [IIT, Chicago; Luo, Tianhuan [LBNL, Berkeley; Moretti, Alfred [Fermilab; Neuffer, David [Fermilab; Peterson, David [Fermilab; Popovic, Milorad [Fermilab; Yonehara, Katsuya [Fermilab

    2016-06-01

    We report operational experience from the prototype RF module for the Muon Ionization Cooling Experiment (MICE) with final production couplers at Fermilab's MuCool Test Area. This is the last step in fully qualifying the RF modules for operation in the experiment at RAL.

  1. Very high coupling of TM polarised light in photonic crystal directional couplers

    DEFF Research Database (Denmark)

    Borel, Peter Ingo; Thorhauge, Morten; Frandsen, Lars Hagedorn

    2003-01-01

    The experimental and simulated spectra for TE and TM polarised light for the transmission through photonic crystal directional couplers are presented. The 3D FDTD simulations successfully explain all the major features of the experimental spectra as well as the actual transmission level. Especially...

  2. Multipacting Simulations of Tuner-adjustable waveguide coupler (TaCo) with CST

    CERN Document Server

    Shafqat, Nuaman; Wegner, Rolf

    2015-01-01

    Tuner-adjustable waveguide couplers (TaCo) are used to feed microwave power to different RF structures of LINAC4. This paper studies the multipacting phenomenon for TaCo using PIC solver of CST PS. Simulations are performed for complete field sweeps and results are analysed.

  3. Switching dynamics of a two-dimensional nonlinear couplers in a ...

    Indian Academy of Sciences (India)

    The coupled nonlinear Schrödinger equations (CNLSEs) describing our coupler system are analysed using Lagrangian variational method. From the La- grangian, a set of coupled ordinary differential equations (ODEs) describing the system dynamics ... fraction and a part of the input field spreads to the neighbouring core.

  4. Solitary Wave Generation from Constant Continuous Wave in Asymmetric Oppositely Directed Waveguide Coupler

    Directory of Open Access Journals (Sweden)

    Kazantseva E.V.

    2015-01-01

    Full Text Available In a model which describes asymmetric oppositely directed nonlinear coupler it was observed in numerical simulations a phenomenon of solitary wave generation from the input constant continuous wave set at the entrance of a waveguide with negative refraction. The period of solitary wave formation decreases with increase of the continuum wave amplitude.

  5. InGaN directional coupler made with a one-step etching technique

    Science.gov (United States)

    Gao, Xumin; Yuan, Jialei; Yang, Yongchao; Zhang, Shuai; Shi, Zheng; Li, Xin; Wang, Yongjin

    2017-06-01

    We propose, fabricate and characterize an on-chip integration of light source, InGaN waveguide, directional coupler and photodiode, in which AlGaN layers are used as top and bottom optical claddings to form an InGaN waveguide for guiding the in-plane emitted light from the InGaN/GaN multiple-quantum-well light-emitting diode (MQW-LED). The difference in etch rate caused by different exposure windows leads to an etching depth discrepancy using the one-step etching technique, which forms the InGaN directional coupler with the overlapped underlying slab. Light propagation results directly confirm effective light coupling in the InGaN directional coupler, which is achieved through high-order guided modes. The InGaN waveguide couples the modulated light from the InGaN/GaN MQW-LED and transfers part of light to the coupled waveguide via the InGaN directional coupler. The in-plane InGaN/GaN MQW-photodiode absorbs the guided light by the coupled InGaN waveguide and induces the photocurrent. The on-chip InGaN photonic integration experimentally demonstrates an in-plane light communication with a data transmission of 50 Mbps.

  6. Broadband TE01 mode fiber coupler based on dual-core photonic crystal fiber

    DEFF Research Database (Denmark)

    Wang, Chun-can; Wang, Mei-hui

    2014-01-01

    A broadband TE01 mode fiber coupler based on dual-core photonic crystal fiber (PCF) is proposed by introducing gold nanowires and fluorine-doped (F-doped) layers in the core areas. With an appropriate choice of the parameters of the F-doped layers and air hole space, the wavelength bandwidth can...

  7. Optical fiber monitored by a directional coupler for delivering laser radiation in medical treatments.

    Science.gov (United States)

    Sottini, S; Lombardo, S; Russo, V

    1995-05-01

    The safety of therapeutic laser treatments could be strongly improved by introducing real-time monitoring to the fiber delivery system. Since any fiber damage leads to a significant variation of the backscatter, its detection could be exploited to monitor the system, in particular the fiber trip. To assess this potential, the backscattered modal power distribution (BMPD) from flat, bulb, and damaged fiber tips were investigated. The BMPD detection was accomplished by using a conventional beam-splitter method and two directional couplers: a prism-fiber and a fiber-fiber lapped coupler. Unlike the conventional method, use of the couplers allows for the separate detection of backscattered and forward transmitted signals. Therefore variations in the backscatter that are due to only a change in the laser pulse can be determined. Moreover, the directional couplers, because of the amplification of high-index modes, allow for an increase in sensitivity of the method. This was particularly evident in our tests on fiber tips that had been dipped into water to obtain a better simulation of the real working conditions. Finally, the influence of the target on the BMPD was investigated as a function of its distance from the fiber tip. All the tests confirm that the target must be taken into account if the distance is <1 mm, but the monitoring system can also be used when the fiber tip works in contact with the tissue wall provided that one can ensure contact by pushing the tip against the target wall.

  8. Arrayed silicon prism coupler for a terahertz-wave parametric oscillator.

    Science.gov (United States)

    Kawase, K; Shikata, J; Minamide, H; Imai, K; Ito, H

    2001-03-20

    Using room-temperature parametric oscillation of a LiNbO3 crystal pumped by a Q-switched Nd:YAG laser with a simple configuration, we have realized a widely tunable coherent terahertz- (THz-) wave source in the range between 1 and 3 THz. Inasmuch as the THz wave is affected by total internal reflection at the crystal edge, we used a Si prism coupler to couple out the THz wave. We introduce an arrayed Si-prism coupler that increases the efficiency and decreases the diffraction angle. By use of the arrayed-prism coupler, there is a sixfold increase in coupling efficiency and a 40% decrease in the far-field beam diameter, compared with the use of a single-prism coupler. We discuss the negative effect of the free carriers at the Si-prism surface that is excited by the scattered pump beam, and the positive effect of cavity rotation on the unidirectional radiation of the THz wave from a Si prism.

  9. El Abencerraje como problema heroico: una lectura según modelos homéricos

    Directory of Open Access Journals (Sweden)

    Terradas, José Carlos

    2012-06-01

    Full Text Available Despite the deep epic and mythological relations that the Abencerraje presents and the knowledge in this area of the alleged author, Antonio de Villegas, we still lack of studies connecting the work with Homeric patterns. This paper represents an effort to illustrate how the quest for beauty that initially was understood as the retrieving of the beloved lady, ultimately becomes an ethical quest that favors heroic asceticism. We will critically review about the characters of Narváez and Abindarráez, their presumed differences, their commitment to attain public esteem, their detachment from sensual pleasures in order to complete a chivalrous and warlike paradigm. Finally, we stop at the cosmology that the work presents in order to explain an oppressive religious system masquerading as Christianity, but that basically contains much of the Greek concept of the envy of the gods.A pesar de las profundas relaciones épicas y mitológicas que presenta el Abencerraje y el conocimiento en esta materia del presunto autor, Antonio de Villegas, aún carecemos de estudios que conecten la obra con los modelos homéricos. Este artículo representa un esfuerzo por ejemplificar cómo la búsqueda de la belleza que en un principio se entendía como recuperación de la amada, se transforma en una búsqueda ética que propicia la ascesis heroica. Haremos una revisión crítica acerca de Nárvaez y Abindarráez, de sus supuestas diferencias, del compromiso de ambos con el logro de la admiración pública, de su alejamiento de los placeres sensuales para consumar un paradigma caballeresco y guerrero compartido. Finalmente, nos detendremos en la cosmología que presenta la obra con el objeto de explicar un sistema religioso opresivo que se disfraza de cristianismo, pero que en el fondo contiene mucho del concepto griego de la envidia de los dioses.

  10. Homologous expression of aspartokinase (ask) gene in Streptomyces clavuligerus and its hom-deleted mutant: effects on cephamycin C production.

    Science.gov (United States)

    Özcengiz, Gülay; Okay, Sezer; Ünsaldı, Eser; Taşkın, Bilgin; Liras, Paloma; Piret, Jacqueline

    2010-01-01

    In this study, the effect of homologous multiple copies of the ask gene, which encodes aspartokinase catalyzing the first step of the aspartate pathway, on cephamycin C biosynthesis in S. clavuligerus NRRL 3585 and its hom mutant was investigated. The intracellular pool levels of aspartate pathway amino acids accorded well with the Ask activity levels in TB3585 and AK39. When compared with the control strain carrying vector alone without any gene insert, amplification of the ask gene in the wild strain resulted in a maximum of 3.1- and 3.3-fold increase in specific, 1.7- and 1.9-fold increase in volumetric cephamycin C production when grown in trypticase soy broth (TSB) and a modified chemically defined medium (mCDM), respectively. However, expression of multicopy ask gene in a hom-deleted background significantly decreased cephamycin C yields when the cells were grown in either TSB or mCDM, most probably due to physiological disturbance resulting from enzyme overexpression and high copy number plasmid burden in an auxotrophic host, respectively. © 2010 Landes Bioscience

  11. A Cascaded Self-Similar Rat-Race Hybrid Coupler Architecture and its Compact Ka-Band Implementation

    Science.gov (United States)

    2017-03-01

    coupler architecture that performs broadband in-phase and differential signal generation while maintaining a very compact passive structure size. A...A Cascaded Self-Similar Rat-Race Hybrid Coupler Architecture and its Compact Ka-band Implementation Edgar F. Garay, Min-Yu Huang, and Hua Wang...monolithic passive structures do not directly benefit from such device scaling, where their performance and form- factor are mostly determined by their

  12. Further Clarification on the Hom, Mitchell, Lee, and Griffeth (2012) Model: Reply to Bergman, Payne, and Boswell (2012) and Maertz (2012)

    Science.gov (United States)

    Griffeth, Rodger W.; Lee, Thomas W.; Mitchell, Terence R.; Hom, Peter W.

    2012-01-01

    In this article, we reply to Bergman, Payne, and Boswell (2012) and Maertz (2012), who commented on our reconceptualization of the employee turnover criterion and proximal withdrawal states (Hom, Mitchell, Lee, & Griffeth, 2012). We agree with some points (e.g., anticipated destinations) but take issue with others (e.g., turnover intentions as…

  13. A new shielding effectiveness measurement method based on a skin-effect transmission line coupler

    Directory of Open Access Journals (Sweden)

    T. Kleine-Ostmann

    2007-06-01

    Full Text Available We propose a new convenient material shielding effectiveness measurement method based on a skin-effect transmission line coupler. The method is somewhat similar to the arrangement with two coupled TEM cells known from literature. The transmission line coupler consists of a pair of identical transmission line 2-port devices. Each device contains a coaxial waveguide, with a circular inner conductor and an outer conductor having a square cross section. One side of the outer conductor is left completely open as a slot. The slot is surrounded by a large metal housing to contact the two halves. As a measure for the shielding effectiveness the coupling between the two devices is measured in terms of scattering parameters after the test material is brought between the two halves. The devices can be used in a range from low frequencies to a few GHz.

  14. Research of new packaging and cooling technique for high power fiber laser used pump coupler

    Science.gov (United States)

    Mu, Wei; Si, Xu; Lin, Ya-jun; Xu, Cheng-lin; Ma, Yun-liang; Xiao, Chun

    2015-10-01

    This article analyzes the advantages and disadvantages of a packaging structure for pump coupler, where common heat conduction material is used. In this study, the possibility of using new technology of thermal conductivity is discussed. We also proposes a solution that make the function and effect of package more uniform. A serial of experiments are done for research the cooling effect and the working reliability of the fiber combiners and couplers. Experiment proves that after improved method of package, the cooling speed increases significantly comparing the sample with old type of package technique. The technique discussed in this paper will make the high power fiber laser working long time with steady power output and high efficiency.

  15. Multiwavelength mode-locked cylindrical vector beam fiber laser based on mode selective coupler

    Science.gov (United States)

    Huang, Ping; Cai, Yu; Wang, Jie; Wan, Hongdan; Zhang, Zuxing; Zhang, Lin

    2017-10-01

    We propose and demonstrate a multiwavelength mode-locked fiber laser with cylindrical vector beam generation for the first time, to the best of our knowledge. The mode-locking mechanism is based on a nonlinear polarization rotation effect in fiber, and the multiwavelength operation is contributed to by an in-line birefringence fiber filter with periodic multiple passbands, formed by incorporating a section of polarization maintaining fiber into the laser cavity with a fiber polarizer. Furthermore, by using a home-made mode selective coupler, which acts as both a mode converter from fundamental mode to higher-order mode and an output coupler, multiwavelength mode-locked cylindrical vector beams have been obtained. This may have potential applications in mode-division multiplexing optical fiber communication and material processing.

  16. Compact high-efficiency perfectly-vertical grating coupler on silicon at O-band.

    Science.gov (United States)

    Wang, Siya; Hong, Yue; Zhu, Yuntao; Chen, Jingye; Gao, Shengqian; Cai, Xinlun; Shi, Yaocheng; Liu, Liu

    2017-09-04

    A compact, high-efficiency grating coupler is demonstrated for interfacing a silicon waveguide and a perfectly-vertical fiber at O-band. The grating lies on a tilted silicon membrane for minimizing the reflections. Circular grating lines are adopted to shorten the overall device length to about 60μm. 57% peak coupling efficiency and >28nm 1-dB coupling bandwidth are obtained experimentally. Back reflections of 1% to the silicon waveguide and the single mode fiber are theoretically estimated. The processing flow to realize the proposed structure is discussed in detail. The fabrication control over the tilted angle of the silicon membrane is investigated. The approach by applying an oxide cladding to improve the stability of the membrane is also introduced. The present grating coupler is compatible to common fabrication processes for silicon photonic chips.

  17. All-fiber 6-mode multiplexers based on fiber mode selective couplers.

    Science.gov (United States)

    Chang, Sun Hyok; Moon, Sang-Rok; Chen, Haoshuo; Ryf, Roland; Fontaine, Nicolas K; Park, Kyung Jun; Kim, Kwangjoon; Lee, Joon Ki

    2017-03-06

    All-fiber 6-mode multiplexer composed of two consecutive LP11-mode selective couplers (MSC), two LP21-MSCs and an LP02-MSC is fully characterized by wavelength-swept interferometer technique. The MSCs are fabricated by polished-type fiber couplers coupling LP01 mode of a single mode fiber into a higher-order mode of a few mode fiber. A pair of the mode multiplexers has minimum mode dependent loss of 4 dB and high mode group selectivity of over 15 dB. Mode division multiplexed transmission enabled by the all-fiber mode multiplexers is demonstrated over fiber spans of 117 km employing an in-line multi-mode optical amplifier. 6 modes of 120 Gb/s dual polarization quadrature phase shift keying signals combined with 30 wavelength channels are successfully transmitted.

  18. Hybrid normal-reverse prism coupler for light-emitting diode backlight systems.

    Science.gov (United States)

    Aoyama, Shigeru; Funamoto, Akihiro; Imanaka, Koichi

    2006-10-01

    For the first time to our knowledge, a hybrid normal-reverse prism coupler was formed on the bottom surface of a light guide in a LED backlight system to achieve a thin, lightweight, LED backlight system. The hybrid prism coupler (HPC) simultaneously exhibits two functions: extraction of guided light from the light guide and focusing the radiated light from the light guide, corresponding to the optical functions of the prism and diffusive sheets used in conventional LED backlight systems. Therefore, using a HPC eliminates the prism and diffusive sheets that have been indispensable optical elements in conventional LED backlight systems, which consequently reduces the thickness of the LED backlight system by 40% compared with conventional systems.

  19. Different pathways of the formation of highly oxidized multifunctional organic compounds (HOMs from the gas-phase ozonolysis of β-caryophyllene

    Directory of Open Access Journals (Sweden)

    S. Richters

    2016-08-01

    Full Text Available The gas-phase mechanism of the formation of highly oxidized multifunctional organic compounds (HOMs from the ozonolysis of β-caryophyllene was investigated in a free-jet flow system at atmospheric pressure and a temperature of 295 ± 2 K. Reaction products, mainly highly oxidized RO2 radicals containing up to 14 oxygen atoms, were detected using chemical ionization – atmospheric pressure interface – time-of-flight mass spectrometry with nitrate and acetate ionization. These highly oxidized RO2 radicals react with NO, NO2, HO2 and other RO2 radicals under atmospheric conditions forming the first-generation HOM closed-shell products. Mechanistic information on the formation of the highly oxidized RO2 radicals is based on results obtained with isotopically labelled ozone (18O3 in the ozonolysis reaction and from hydrogen/deuterium (H/D exchange experiments of acidic H atoms in the products. The experimental findings indicate that HOM formation in this reaction system is considerably influenced by the presence of a double bond in the RO2 radicals primarily formed from the β-caryophyllene ozonolysis. Three different reaction types for HOM formation can be proposed, allowing for an explanation of the detected main products: (i the simple autoxidation, corresponding to the repetitive reaction sequence of intramolecular H-abstraction of a RO2 radical, RO2  →  QOOH, and subsequent O2 addition, next forming a peroxy radical, QOOH + O2  →  R′O2; (ii an extended autoxidation mechanism additionally involving the internal reaction of a RO2 radical with a double bond forming most likely an endoperoxide and (iii an extended autoxidation mechanism including CO2 elimination. The individual reaction steps of the reaction types (ii and (iii are uncertain at the moment. From the product analysis it can be followed that the simple autoxidation mechanism accounts only for about one-third of the formed HOMs. Time

  20. A miniature reflective micro-force sensor based on a microfiber coupler.

    Science.gov (United States)

    Chen, Ye; Yan, Shao-cheng; Zheng, Xin; Xu, Fei; Lu, Yan-qing

    2014-02-10

    A compact highly sensitive microfiber coupler based reflective micro-force sensor is presented. The device is fabricated by fusing two twisted optical fibers and then connecting two of the pigtails to form a Sagnac loop. The sensor has a high force sensitivity of ~3754 nm/N which is three orders of magnitude larger than traditional optical fiber force sensors, and a low detection limit of ~1.6 µN. The good repeatability is also shown in this paper.

  1. Birefringence Analysis of Directional Fiber Coupler Induced by Fusion and Coupling Parameters

    OpenAIRE

    Irawan, Dedi; Ali, Jalil

    2013-01-01

    The effect of fusion and coupling parameters to the form of birefringence of coupling region directional fiber coupler is reported. Vector of polarization was determined by using perturbation method that describes the propagation of electric field in single mode fiber coupling induced by stress which is caused by fusion and coupling parameters during fabrication. It is found that the radius of coupling cross section, refractive index different, normalized frequency, and twisting angle signifi...

  2. Birefringence Analysis of Directional Fiber Coupler Induced by Fusion and Coupling Parameters

    OpenAIRE

    Irawan, Dedi; Ali, Jalil; Saktioto, -; Iwantono, -; Defrianto, -

    2015-01-01

    The effect of fusion and coupling parameters to the form of birefringence of coupling region directional fiber coupler is reported. Vector of polarization was determined by using perturbation method that describes the propagation of electric field in single mode fiber coupling induced by stress which is caused by fusion and coupling parameters during fabrication. It is found that the radius of coupling cross section, refractive index different, normalized frequency, and twisting angle signifi...

  3. The oscillating collisions between the three solitons for a dual-mode fiber coupler system

    Science.gov (United States)

    Li, Bang-Qing; Ma, Yu-Lan; Yang, Tie-Mei

    2017-10-01

    The dynamical behaviors of the three-soliton collisions are investigated for a dual-mode fiber coupler system, which is modeled as coupled nonlinear Schrödinger equations describing optical pulse propagations. The three-soliton solutions are constructed by the bilinear method. A class of oscillating collisions is observed. The optical speckle intensity is controllable by setting parameters involved in soliton solution. It is valuable to inspire new ideas in optics and optical engineering.

  4. A Superconducting 180{\\deg} Hybrid Ring Coupler for circuit Quantum Electrodynamics

    OpenAIRE

    Hoffmann, E; Deppe, F.; Niemczyk, T.; Wirth, T.; Menzel, E. P.; Wild, G.; Huebl, H.; Mariantoni, M.; Weißl, T.; Lukashenko, A.; Zhuravel, A. P.; Ustinov, A. V.; Marx, A.; Gross, R.

    2010-01-01

    Superconducting circuit quantum electrodynamics experiments with propagating microwaves require devices acting as beam splitters. Using niobium thin films on silicon and sapphire substrates, we fabricated superconducting 180{\\deg} microstrip hybrid ring couplers, acting as beam splitters with center frequencies of about 6GHz. For the magnitude of the coupling and isolation we find -3.5+/-0.5dB and at least -15dB, respectively, in a bandwidth of 2GHz. We also investigate the effect of reflecti...

  5. Prism coupler jig: interference fringes enable observation of the coupling gap.

    Science.gov (United States)

    Chilwell, J T

    1982-04-01

    A prism coupler jig is described which enables a coupling region to be quickly and easily found when the waveguide is a thin film on a microscope slide. Interference fringes formed on reflection allow observation of the air gap. Consideration is given to the formation of white light and quasi-monochromatic interference fringes. A suitable choice of the refractive index of the right-angle prism enables the m lines to be observed in a convenient observation space.

  6. Analysis of an implantable venous anastomotic flow coupler: experience in head and neck free flap reconstruction.

    Science.gov (United States)

    Zhang, T; Dyalram-Silverberg, D; Bui, T; Caccamese, J F; Lubek, J E

    2012-06-01

    Monitoring microvascular free flaps can present a difficult challenge. This is especially true in cases of buried or intra-oral free flaps. The authors conducted a retrospective review of 19 consecutive free flaps for head and neck reconstruction using a novel monitoring device, which combines a venous anastomotic coupler and an implantable microdoppler (Synovis Micro Companies Alliance Inc., Birmingham, AL, USA). 20 venous anastomoses were performed and monitored with the venous flow coupler device. Monitoring ranged from intra-operatively to postoperative day 7 (mean 4.2 days). Accurate flow signal interpretation was correct in 18 of 20 anastomoses (90%) but only 14 of the 20 coupled anastomoses (70%) were monitored for the complete period of time as desired by the surgeons. All 19 flaps survived. The venous anastomotic flow coupler appears to be a reliable adjunct to free flap monitoring and may help to improve it, with early detection of flap compromise and salvage. Copyright © 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  7. Straightforward and accurate technique for post-coupler stabilization in drift tube linac structures

    CERN Document Server

    Khalvati, Mohammad Reza

    2016-01-01

    The axial electric field of Alvarez drift tube linacs (DTLs) is known to be susceptible to variations due to static and dynamic effects like manufacturing tolerances and beam loading. Post-couplers are used to stabilize the accelerating fields of DTLs against tuning errors. Tilt sensitivity and its slope have been introduced as measures for the stability right from the invention of post-couplers but since then the actual stabilization has mostly been done by tedious iteration. In the present article, the local tilt-sensitivity slope TS 0 n is established as the principal measure for stabilization instead of tilt sensitivity or some visual slope, and its significance is developed on the basis of an equivalent-circuit diagram of the DTL. Experimental and 3D simulation results are used to analyze its behavior and to define a technique for stabilization that allows finding the best post-coupler settings with just four tilt-sensitivity measurements. CERN ’ s Linac4 DTL Tank 2 and Tank 3 have been stabilized succ...

  8. La pervivencia de la épica homérica en Edito Rey de Sófocles

    Directory of Open Access Journals (Sweden)

    María Inés Saravia de Grossi

    2017-05-01

    Full Text Available En el presente trabajo proponemos discernir cómo las fuentes de la épica homérica, es decir, Ilíada y Odisea, irrigan el entramado de Edipo Rey. Analizaremos el comienzo de la obra y el discurso del segundo mensajero como sendos proemios; en el centro consideraremos que el interrogatorio, la reconstrucción dialógica que se elabora entre el Episodio II y III, mantiene equivalencias con la teichoscopia (Ilíada III: 161-244 y, luego, asimilaremos el epítome de Odisea o ἀνακεφαλαίωσις (23: 310-343 en relación con el discurso de Edipo en el Éxodo (vv. 1369-1415.

  9. Properties of directional couplers using photonic crystal waveguides

    DEFF Research Database (Denmark)

    Thorhauge, Morten; Borel, Peter Ingo; Frandsen, Lars Hagedorn

    2003-01-01

    Coupled photonic crystal waveguides have been designed and modelled with a 3D finite-difference-time-domain method, and fabricated in silicon-on-insulator material. Good agreement between modelled and measured results has been found.......Coupled photonic crystal waveguides have been designed and modelled with a 3D finite-difference-time-domain method, and fabricated in silicon-on-insulator material. Good agreement between modelled and measured results has been found....

  10. The Many Sides of Happy Lim: aka Hom Ah Wing, Lin Jian Fu, Happy Lum, Lin Chien Fu, Hom Yen Chuck, Lam Kin Foo, Lum Kin Foo, Hom, Lim Goon Wing, Lim Gin Foo, Gin Foo Lin, Koon Wing Lim, Henry Chin, Lim Ying Chuck, Lim Ah Wing, et. al.

    Directory of Open Access Journals (Sweden)

    Gordon H. Chang

    2010-03-01

    Full Text Available

    Known to the FBI, INS, and IRS as Mr. Ah Wing Hom, he was also Lin Jian Fu, Jian Fu (Tough Guy, or just Fu to the readers of the many poems and short stories he published in Chinese over four decades in the twentieth century. And to still others, primarily English-readers of his writing, he was Happy Lim, an ironic, even tragically bizarre name, as his life was far from pleasant. On New Year's Day 1986, he died alone in a dingy San Francisco Chinatown bachelor hotel suffering from a bacterial infection and a chronic blood disorder that had required the amputation of all his toes the year before. He was seventy-eight years of age and had spent most of his life within blocks of where he died.

  11. The Many Sides of Happy Lim: aka Hom Ah Wing, Lin Jian Fu, Happy Lum, Lin Chien Fu, Hom Yen Chuck, Lam Kin Foo, Lum Kin Foo, Hom, Lim Goon Wing, Lim Gin Foo, Gin Foo Lin, Koon Wing Lim, Henry Chin, Lim Ying Chuck, Lim Ah Wing, et. al.

    Directory of Open Access Journals (Sweden)

    Gordon H. Chang

    2010-03-01

    Full Text Available Known to the FBI, INS, and IRS as Mr. Ah Wing Hom, he was also Lin Jian Fu, Jian Fu (Tough Guy, or just Fu to the readers of the many poems and short stories he published in Chinese over four decades in the twentieth century. And to still others, primarily English-readers of his writing, he was Happy Lim, an ironic, even tragically bizarre name, as his life was far from pleasant. On New Year's Day 1986, he died alone in a dingy San Francisco Chinatown bachelor hotel suffering from a bacterial infection and a chronic blood disorder that had required the amputation of all his toes the year before. He was seventy-eight years of age and had spent most of his life within blocks of where he died.

  12. Near-field probing of photonic crystal directional couplers

    DEFF Research Database (Denmark)

    Volkov, V. S.; Bozhevolnyi, S. I.; Borel, Peter Ingo

    2006-01-01

    We report the design, fabrication and characterization of a photonic crystal directional with a size of ~20 x 20 mm2 fabricated in silicon-on-insulator material. Using a scanning near-field optical microscope we demonstrate a high coupling efficiency for TM polarized light at telecom wavelengths...

  13. Improved silica-PLC Mach-Zehnder interferometer type optical switches with error dependence compensation of directional coupler

    Science.gov (United States)

    Wang, Jun; Yi, Jia; Guo, Lijun; Liu, Peng; Hall, Trevor J.; Sun, DeGui

    2017-03-01

    For the most popular structure of planer lightwave circuit (PLC) 2×2 thermo-optic switches, Mach-Zehnder interferometer (MZI), a full range of splitting ratio errors of directional coupler (DC) are investigated. All the parameters determining the splitting ratio are the dimensions and the refractive indices of the waveguide core and cladding layers. In this work, the coherent relationships between the waveguide size and the refractive indices are analyzed and then the error compensation between the width and the refractive index of waveguide core, and the controllable effect of over clad layer refractive index error upon the MZI-type optical switch are all discovered with numerical calculation and BPM simulations. Then, an MZI-type 2×2 thermo-optic switch having a higher error tolerance is established with the efficient optimizations of all the 3 dB-DC parameters. As a result, for the symmetric MZI switch, an insertion loss of 1.5 dB and optical extinction ratio of over 20 dB are realized for the average tolerance of±5.0%. An asymmetric arm optical phase and unequal arm lengths is also employed to improve the uniformities of insertion loss. The agreements between the designs and the experiments are recognized, leading to a wide adoption of practical silica-PLC optical switch products.

  14. Planar waveguide solar concentrator with couplers fabricated by laser-induced backside wet etching

    Science.gov (United States)

    Zhang, Nikai

    Solar radiation can be converted directly into electricity by using the photovoltaic effect, which represents the principle of operation of solar cells. Currently, most solar cells are made of crystalline silicon and have a conversion efficiency of about 20% or less. Multi-junction solar cells, made of III-V compound semiconductors, can have efficiencies in excess of 40%. The main factor that prohibits such high-efficiency technologies from wider acceptance is the cost. An alternative approach to using large-area expensive solar cells is to employ lower cost optics and concentrate the solar radiation to smaller cell area, which is the basic principle of solar concentrators. In this thesis, we consider a solar concentrator module that consists of a combination of a lens array and a slab waveguide with etched conical holes on one side of the waveguide, which are aligned with the lenslets. Sunlight coming through each of these lenslets is focused on the backside of the waveguide, where a coupling structure (an etched cone) is fabricated. This coupler changes the propagation direction of the incident light in such a way that light is guided through total internal reflection (TIR) within the glass slab and eventually reaches a solar cell, which is properly mounted on the side of the slab. The concept of this concentrated photovoltaic (CPV) system is based on a planar light guide solar concentrator module, proposed earlier by another group. This project builds on the original idea by including the following substantial modifications. The lens array is to be made of solid glass by a mold technology and provided to us by our industrial partner, Libbey, Inc., as opposed to silicone on glass technology, in which the lenses are made out of silicone and sit on a glass substrate. The coupling structures are cone-shaped holes etched directly into the solid glass waveguide, as opposed to coupling structures that are formed by addition of polymeric layer and consequent patterning

  15. A novel type of forward coupler slotted stripline pickup electrode for non-relativistic particle beams

    CERN Document Server

    Caspers, F

    2011-01-01

    A novel type of slotted or perforated strip-line pick-up or kicker electrode structure for non relativistic particle beams with b=v/c values around 0.7 is presented. This slotted structure is to be used as a forward coupler with the output signal taken from the downstream end and has a rather large relative bandwidth of several octaves. Possible applications are stochastic cooling systems e.g. for ions beams in the momentum range mentioned above. This electrode may also be used for Schottky diagnostics.

  16. TM grating coupler on low-loss LPCVD based Si3N4 waveguide platform

    Science.gov (United States)

    Dabos, G.; Manolis, A.; Giesecke, A. L.; Porschatis, C.; Chmielak, B.; Wahlbrink, T.; Pleros, N.; Tsiokos, D.

    2017-12-01

    We demonstrate, for the first time to our knowledge, a fully etched TM grating coupler for low-loss Low-Pressure-Chemical-Vapor-Deposition (LPCVD) based silicon nitride platform with a coupling loss of 6.5 dB at 1541 nm and a 1 dB bandwidth of 55 nm, addressing applications where TM polarization is a pre-requisite. The proposed GC and the 360 nm × 800 nm strip based Si3N4 waveguides have been fabricated by optical projection lithography using an i-line stepper tool enabling low-cost and mass manufacturing of photonic-integrated-circuits.

  17. Compact, low-loss, fused biconical taper couplers: overcoupled operation and antisymmetric supermode cutoff.

    Science.gov (United States)

    Bilodeau, F; Hill, K O; Johnson, D C; Faucher, S

    1987-08-01

    The automated manufacture and characterization of compact four-port highly overcoupled fused couplers is reported. During the pulling stage of the manufacturing process, the light power in such devices is observed to cycle back and forth up to 1000 times between the two output ports for elongations smaller than 20 mm. For sufficiently long pulls, antisymmetric supermode cutoff has been observed for the first time to our knowledge, manifested by a sudden cessation of the coupling process. The measured wavelength dependence of the coupling ratio together with the device dimensions are consistent with the observation of cutoff as observed in pull-signature characteristics.

  18. Determining the refractive index and thickness of thin films from prism coupler measurements

    Science.gov (United States)

    Kirsch, S. T.

    1981-01-01

    A simple method of determining thin film parameters from mode indices measured using a prism coupler is described. The problem is reduced to doing two least squares straight line fits through measured mode indices vs effective mode number. The slope and y intercept of the line are simply related to the thickness and refractive index of film, respectively. The approach takes into account the correlation between as well as the uncertainty in the individual measurements from all sources of error to give precise error tolerances on the best fit values. Due to the precision of the tolerances, anisotropic films can be identified and characterized.

  19. A facetless regrowth-free single mode laser based on MMI couplers

    Science.gov (United States)

    Caro, Ludovic; Kelly, Niall P.; Dernaika, Mohamad; Shayesteh, Maryam; Morrissey, Padraic E.; Alexander, Justin K.; Peters, Frank H.

    2017-09-01

    This paper presents a facetless, tunable laser operating near 1575 nm, as well as a theoretical model predicting spectral features of the laser. The lasers were fabricated without regrowth or advanced lithography techniques, and are based on MMI couplers and etched facets. Coarse vernier tuning was achieved over a range of 25 nm, while fine, thermal tuning was also demonstrated over a range of 1.5 nm. SMSR values of 25 dB and higher were observed, with a measured laser linewidth of 600 kHz.

  20. Compensation of Incomplete Round Trip in an Herriott Multipass-Based Kerr-Lens Mode-Locked Ti:Sapphire Oscillator via an Output Coupler Position

    Science.gov (United States)

    Song, Dong Hoon; In Hwang, Sung; Ko, Do-Kyeong

    2011-03-01

    We examined the soft-aperture Kerr-lens mode-locked femtosecond Ti:sapphire oscillator derived from an Herriott multi-pass cavity (HMPC). Additionally, a novel and simple configuration was provided to extend the cavity length, the HMPC consisting of notched, flat and curved (R = 4 m) mirrors by which beams were injected and extracted. To compensate for beams which failed to complete round trips, the configuration was designed and analyzed as a function of the output coupler position. Such an oscillator generated 21.5 nJ, 34 fs pulses at a repetition rate of approximately 13.5 MHz; the spectral bandwidth represented 20 nm, corresponding to a time-bandwidth product of 0.33, assuming a sech2 fit.

  1. Towards on-chip photon-pair bell tests: Spatial pump filtering in a LiNbO3 adiabatic coupler

    Science.gov (United States)

    Solntsev, Alexander S.; Liu, Tong; Boes, Andreas; Nguyen, Thach G.; Wu, Che Wen; Setzpfandt, Frank; Mitchell, Arnan; Neshev, Dragomir N.; Sukhorukov, Andrey A.

    2017-12-01

    Nonlinear optical waveguides enable the integration of entangled photon sources and quantum logic gates on a quantum photonic chip. One of the major challenges in such systems is separating the generated entangled photons from the pump laser light. In this work, we experimentally characterize double-N-shaped nonlinear optical adiabatic couplers designed for the generation of spatially entangled photon pairs through spontaneous parametric down-conversion, while simultaneously providing spatial pump filtering and keeping photon-pair states pure. We observe that the pump photons at a wavelength of 671 nm mostly remain in the central waveguide, achieving a filtering ratio of over 20 dB at the outer waveguides. We also perform classical characterization at the photon-pair wavelength of 1342 nm and observe that light fully couples from an input central waveguide to the outer waveguides, showing on chip separation of the pump and the photon-pair wavelength.

  2. Thure von Uexkülls semiotisches Modell des Menschen als Grundlage für eine moderne Theorie der Homöopathie

    OpenAIRE

    Schmidt, Josef M.

    2012-01-01

    Während die konventionelle moderne Medizin ihr Selbstverständnis und ihre Praxis weitgehend am Vorbild der konventionellen Naturwissenschaft orientiert, erhebt die Homöopathie den Anspruch, Patienten nicht reduktionistisch, sondern individuell und ganzheitlich zu erfassen und zu behandeln. Gemäss der Lehre Samuel Hahnemanns (1755–1843) ist dazu statt des materialistisch-mechanistischen ein semiotisch-phänomenologischer Ansatz anzuwenden. Während die Anweisungen Hahnemanns für die Praxis klar,...

  3. An optical resonator with insertable scraper output coupler for the JAERI far-infrared free-electron laser

    CERN Document Server

    Nagai, R; Nishimori, N; Sawamura, M; Kikuzawa, N; Shizuma, T; Minehara, E J

    2001-01-01

    The performance of an optical resonator featuring an insertable scraper output coupler was evaluated for the JAERI far-infrared free-electron laser. An efficiency factor of the resonator was introduced for evaluation. The efficiency factor was derived from the amount of the output coupling and diffractive loss of the optical resonator, which were calculated by using an optical mode calculation code, using the iterative computation called Fox-Li procedure. As a result of the evaluation, it was found that the insertable scraper coupler was the most suitable for the far-infrared free-electron lasers.Dependencies of insertion direction and scraper radius were also investigated to find out the optimum geometry of the insertable scraper coupler. It was found that the optimum direction of the scraper was parallel to the wiggling plane of the electron beam and the efficiency of the optical resonator increased with the enlargement of the scraper radius.

  4. Efeitos contextuais no acesso lexical de palavras polissêmicas e homônimas = Contextual effects on lexical access of polysemic and homonym words

    Directory of Open Access Journals (Sweden)

    Amaral, Bruna Rodrigues do

    2013-01-01

    Full Text Available No presente texto discutimos como palavras polissêmicas e homônimas são acessadas e qual o papel do contexto durante a etapa de acesso. Trabalhos clássicos como Swinney (1979 e Tanenhaus et al. (1979 defendem a hipótese do acesso múltiplo, para a qual o contexto age apenas tardiamente no acesso lexical de palavras ambíguas. Já Tabossi e Zardon (1993 e Simpson (1994 defendem a hipótese do acesso seletivo, segundo a qual apenas o sentido especificado pelo contexto é acessado na leitura de uma palavra ambígua. Para verificar a validade dessas hipóteses no acesso a palavras polissêmicas e homônimas realizamos três experimentos de cross-modal priming. Os resultados corroboram a hipótese do acesso múltiplo. No que concerne à relação entre polissemia e homonímia, nossos achados fornecem evidências para a hipótese de que palavras polissêmicas e homônimas são acessadas da mesma forma, mesmo que haja mais sentidos diacronicamente associados às polissemias

  5. Analytical modeling and analysis of magnetic field and torque for novel axial flux eddy current couplers with PM excitation

    Science.gov (United States)

    Li, Zhao; Wang, Dazhi; Zheng, Di; Yu, Linxin

    2017-10-01

    Rotational permanent magnet eddy current couplers are promising devices for torque and speed transmission without any mechanical contact. In this study, flux-concentration disk-type permanent magnet eddy current couplers with double conductor rotor are investigated. Given the drawback of the accurate three-dimensional finite element method, this paper proposes a mixed two-dimensional analytical modeling approach. Based on this approach, the closed-form expressions of magnetic field, eddy current, electromagnetic force and torque for such devices are obtained. Finally, a three-dimensional finite element method is employed to validate the analytical results. Besides, a prototype is manufactured and tested for the torque-speed characteristic.

  6. Efficient silicon PIC mode multiplexer using grating coupler array with aluminum mirror for few-mode fiber

    DEFF Research Database (Denmark)

    Ding, Yunhong; Yvind, Kresten

    2015-01-01

    We demonstrate a silicon PIC mode multiplexer using grating couplers. An aluminum mirror is introduced for coupling efficiency improvement. A highest coupling efficiency of –10.6 dB with 3.7 dB mode dependent coupling loss is achieved.......We demonstrate a silicon PIC mode multiplexer using grating couplers. An aluminum mirror is introduced for coupling efficiency improvement. A highest coupling efficiency of –10.6 dB with 3.7 dB mode dependent coupling loss is achieved....

  7. Enxertos valvares aórticos homólogos: estudo experimental em cães

    Directory of Open Access Journals (Sweden)

    Rui Manoel Sequeira de ALMEIDA

    1998-01-01

    Full Text Available Vinte cães foram divididos em dois grupos de dez, sendo um o grupo doador (Grupo 1 e o outro, o receptor (Grupo 2. Todos os animais do grupo 1 foram submetidos a uma toracotomia mediana e sacrificados, para a retirada do coração e da valva aórtica; os cães do grupo 2 foram submetidos a uma laparotomia mediana para o implante das valvas aórticas homólogas na aorta abdominal infra-renal. O peso médio dos cães do grupo 1 era de 5,5 ± 1,7 kg e o diâmetro médio da aorta descendente de 11,8 ± 1,4 mm. No grupo 2 o peso médio era de 11,9 ± 2,3 kg e o diâmetro da aorta abdominal, de 8,8 ± 1,2 mm. A operação no grupo 2 teve como intercorrência a lesão do conduto linfático, em 4 casos, sendo o tempo médio de isquemia, durante o implante do enxerto homólogo, de 37,6 ± 13,3 min. Os animais foram acompanhados por um período de trinta dias, à exceção de 3. Um cão faleceu no décimo dia de pós-operatório por infarto da artéria mesentérica inferior; um segundo foi sacrificado no décimo quarto dia, por apresentar deiscência parcial da ferida cirúrgica, e o terceiro se evadiu no vigésimo quinto dia de pós-operatório. Dois animais apresentaram deiscência da incisão cirúrgica, levando a uma morbidade de 20%. No trigésimo dia, todos os animais sobreviventes foram submetidos a nova laparotomia, quando foram analisados as aderências da cavidade abdominal e o hematoma em torno do enxerto homólogo, e foram aferidas e registradas as pressões proximal e distal ao enxerto valvar (gradiente médio de 25 mmHg. Após o sacrifício do animal, os enxertos foram explantados para a análise das válvulas que eram normais, à excepção de dois, que apresentavam trombos e retração com fibrose, porém, sem significação clínica. Conclui-se que o modelo é viável para estudos futuros sobre valvas aórticas homólogas.The aim of this research was to develop an experimental model, with dogs, to study homologous aortic valve grafts. A

  8. Design and analysis of large-core single-mode windmill single crystal sapphire optical fiber

    Science.gov (United States)

    Cheng, Yujie; Hill, Cary; Liu, Bo; Yu, Zhihao; Xuan, Haifeng; Homa, Daniel; Wang, Anbo; Pickrell, Gary

    2016-06-01

    We present a large-core single-mode "windmill" single crystal sapphire optical fiber (SCSF) design, which exhibits single-mode operation by stripping off the higher-order modes (HOMs) while maintaining the fundamental mode. The "windmill" SCSF design was analyzed using the finite element analysis method, in which all the HOMs are leaky. The numerical simulation results show single-mode operation in the spectral range from 0.4 to 2 μm in the windmill SCSF, with an effective core diameter as large as 14 μm. Such fiber is expected to improve the performance of many of the current sapphire fiber optic sensor structures.

  9. Improvement of beam quality in unstable resonators by a conical output coupler

    Science.gov (United States)

    Hu, A.; Chen, P.; Wang, Y.; Li, S.; Lei, J.; Luo, X.; Liu, Z.; Liang, Q.

    2015-03-01

    A novel conical output coupler for positive-branch unstable resonators has been proposed to improve the output beam quality. With the application of an inner cone annular scraper and an outer cone reflector, a realization of the output beam from unstable resonator with solid core is introduced. The feasibility of this conical output coupler with solid beam is examined numerically and experimentally with the help of a commercial fast transverse flow (FTF) CO2 laser. The characteristics of the output coupling beam in near field and far field are discussed. Under the definition of 86.5 % power content, the M {pc/2} factors of original annular beam and improved solid beam are 5.22 and 1.16 in simulation. In experiment, the M {pc/2} factor of the original annular beam from the commercial FTF CO2 laser is more than 10, while the M {pc/2} factor of the improved solid beam is 3.82. Both simulation and experimental results show that the beam quality can be improved a lot by introducing this output coupling configuration.

  10. GaN directional couplers for on-chip optical interconnect

    Science.gov (United States)

    Yuan, Jialei; Gao, Xumin; Yang, Yongchao; Zhu, Guixia; Yuan, Wei; Choi, Hoi Wai; Zhang, Zhiyu; Wang, Yongjin

    2017-04-01

    Here, we propose, fabricate and characterize GaN directional couplers for on-chip optical interconnect on a GaN-on-silicon platform. Suspended InGaN/GaN multiple-quantum-well diodes are adopted for both the transmitter and the receiver, and GaN directional couplers are used to achieve the light coupling between suspended waveguides that are directly connected to the transmitter and the receiver. The proposed on-chip optical interconnects are experimentally demonstrated by light propagation and in-plane data transmission using visible light. The light propagation images directly show that the emitted light can be laterally coupled into the suspended waveguide, and the guided light from the input waveguide then couples to the coupled waveguide due to the overlapped slab. The receiver detects the transmitted light from the coupled waveguide to complete the in-plane visible light communication process, as confirmed by pseudo-random binary sequence data and eye diagrams at the transmission rate of 30 Mbps.

  11. Fiber pigtailed thin wall capillary coupler for excitation of microsphere WGM resonator in chemical sensing

    Science.gov (United States)

    Wang, Hanzheng; Lan, Xinwei; Huang, Jie; Yuan, Lei; Xiao, Hai

    2014-06-01

    Optical microresonators have been proven as an effective means for sensitive chemical sensors development. The changes in refractive index near the resonator surface lead to the effective refractive index change and thus a shift at certain resonance wavelength. The high quality (Q) whispering gallery modes (WGMs) contributed by the rotationally symmetric structures will interact with the local circumstances through the evanescent field. The high sensitivity in detection was achieved by the long photon lifetime of the high-Q resonator (thus the long light-environment interaction path). In this paper, we present our recent research on using fiber pigtailed capillary coupler for WGM resonator excitation and its sensing applications. Capillary tube with wall thickness of several microns was used as the waveguide. The PMMA microsphere and porous glass microsphere (PGM) were integrated with the etched capillary tube for different sensing purposes. The Q-factors and free spectrum ranges (FSR) of different types of microspheres were measured by coupling light into the microsphere using novel fiber pigtailed capillary coupler. Chemical vapor at different concentrations were tested using PGM microresonator. This alignment free structure provides a new sensing probe based on WGM resonator concept.

  12. Dissection of broad-spectrum resistance of the Thai rice variety Jao Hom Nin conferred by two resistance genes against rice blast.

    Science.gov (United States)

    Chaipanya, Chaivarakun; Telebanco-Yanoria, Mary Jeanie; Quime, Berlaine; Longya, Apinya; Korinsak, Siripar; Korinsak, Siriporn; Toojinda, Theerayut; Vanavichit, Apichart; Jantasuriyarat, Chatchawan; Zhou, Bo

    2017-12-01

    Rice (Oryza sativa) is one of the most important food crops in the world. Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most destructive rice diseases worldwide. To effectively cope with this problem, the use of rice blast resistance varieties through innovative breeding programs is the best strategy to date. The Thai rice variety Jao Hom Nin (JHN) showed broad-spectrum resistance against Thai rice blast isolates. Two QTLs for blast resistance in JHN were reported on chromosome 1 (QTL1) and 11 (QTL11). Monogenic lines of QTL1 (QTL1-C) and QTL11 (QTL11-C) in the CO39 genetic background were generated. Cluster analysis based on the disease reaction pattern of QTL1-C and QTL11-C, together with IRBLs, showed that those two monogenic lines were clustered with IRBLsh-S (Pish) and IRBL7-M (Pi7), respectively. Moreover, sequence analysis revealed that Pish and Pi7 were embedded within the QTL1 and QTL11 delimited genomic intervals, respectively. This study thus concluded that QTL1 and QTL11 could encode alleles of Pish and Pi7, designated as Pish-J and Pi7-J, respectively. To validate this hypothesis, the genomic regions of Pish-J and Pi7-J were cloned and sequenced. Protein sequence comparison revealed that Pish-J and Pi7-J were identical to Pish and Pi7, respectively. The holistic disease spectrum of JHN was found to be exactly attributed to the additive ones of both QTL1-C and QTL11-C. JHN showed broad spectrum resistance against Thai and Philippine rice blast isolates. As this study demonstrated, the combination of two resistance genes, Pish-J and Pi7-J, in JHN, with each controlling broad-spectrum resistance to rice blast disease, explains the high level of resistance. Thus, the combination of Pish and Pi7 can provide a practical scheme for breeding durable resistance in rice against rice blast disease.

  13. 30 CFR 77.805 - Cable couplers and connection boxes; minimum design requirements.

    Science.gov (United States)

    2010-07-01

    ... circuits shall be of the three-phase type and enclosed in a full metallic shell, except that the Secretary... conductor last when being uncoupled when pilot check circuits are used. (b) Cable connection boxes shall be...

  14. Optical Couplers

    Science.gov (United States)

    1975-12-01

    Force project engineer was David A. Zann of the Information Management Branch (AFAL/AAM) . The program manager was J. R. Biard; the project engineers ...approved for publication. h^d ? DAVID A. ZANN Project Engineer CHARI.ES C. GAUDER Acting Chief Information Management Branch System...mimmm ■UWMWIWWIIWH ■- .’ ’ wmw ^vn^fii At this point it was learned that Galileo coats the glass fibers with a lubricant so that they will slide freely

  15. Design of ERL Spoke Cavity For Non-Destructive Assay Research

    Science.gov (United States)

    Sawamura, M.; Nagai, R.; Nishimori, N.; Hajima, R.

    2015-10-01

    We are proposing non-destructive assay system of nuclear materials with laser Compton scattering combined with an energy-recovery linac (ERL) and a laser. Since constructing accelerator system for nuclear safe guard and security requires small cavities, spoke cavities have many advantages such as shortening the distance between cavities, small frequency detune due to micro-phonics and easy adjustment of field distribution for strong cell coupling. Calculations of optimized cavity shape and HOM coupler shape have been performed and rf properties with aluminum spoke cavity model have been also measured. Considering refrigerator system required for superconducting accelerator, we are planning to develop 325MHz spoke cavity which can be practically operated with 4K liquid helium. We have started to fabricate the niobium one-spoke cavity.

  16. Multipacting Simulations of Tuner-adjustable waveguide coupler (TaCo) with CST Particle Studio®

    CERN Document Server

    Shafqat, N; Wegner, R

    2014-01-01

    Tuner-adjustable waveguide couplers (TaCo) are used to feed microwave power to different RF structures of LINAC4. This paper studies the multipacting phenomenon for TaCo using the PIC solver of CST PS. Simulations are performed for complete field sweeps and results are analysed.

  17. 1.28 Tbaud Nyquist-OTDM Transmission over a 7-Core Fiber Using an On-Chip SDM Coupler

    DEFF Research Database (Denmark)

    Hu, Hao; Medhin, Ashenafi Kiros; Ye, Feihong

    2014-01-01

    We have demonstrated the first 1.28-Tbaud Nyquist-OTDM-SDM transmission over a 67.4 - km seven-core fiber with an aggregated data rate of 7.2 Tbit/s using a silicon SDM coupler. 10 - GHz control pulses were transmitted through the center core...

  18. Thermo-optic control of dielectric-loaded plasmonic Mach-Zehnder interferometers and directional coupler switches

    DEFF Research Database (Denmark)

    Gosciniak, J.; Markey, L.; Dereux, A.

    2012-01-01

    We report detailed experimental studies of compact fiber-coupled dielectric-loaded plasmonic waveguide components-Mach-Zehnder interferometers (MZIs) and directional couplers (DCs)-whose operation at telecom wavelengths is controlled via the thermo-optic effect by electrically heating the gold...

  19. On-chip two-mode division multiplexing using tapered directional coupler-based mode multiplexer and demultiplexer

    DEFF Research Database (Denmark)

    Ding, Yunhong; Xu, Jing; Da Ros, Francesco

    2013-01-01

    Abstract: We demonstrate a novel on-chip two-mode division multiplexing circuit using a tapered directional coupler-based TE0&TE1 mode multiplexer and demultiplexer on the silicon-on-insulator platform. A low insertion loss (0.3 dB), low mode crosstalk (

  20. Coupling Characteristics of Fused Optical Fiber Coupler Formed with Single-Mode Fiber and Photonic Crystal Fiber Having Air Hole Collapsed Taper

    Directory of Open Access Journals (Sweden)

    Hirohisa Yokota

    2016-01-01

    Full Text Available Fused coupler forming with a single-mode fiber (SMF and a photonic crystal fiber (PCF is one of the solutions for optical coupling from a light source to a PCF. In this paper, we presented coupling characteristics of a fused fiber coupler formed with an ordinary SMF and a PCF having air hole collapsed taper. A prototype of SMF-PCF coupler with air hole collapsed taper was fabricated using CO2 laser irradiation. The coupling efficiency from SMF to PCF was −6.2 dB at 1554 nm wavelength in the fabricated coupler. The structure of the SMF-PCF coupler to obtain high coupling efficiency was theoretically clarified by beam propagation analysis using an equivalent model of the coupler with simplification. It was clarified that appropriately choosing the prestretched or etched SMF diameter and the length of air hole collapsed region was effective to obtain high coupling efficiency that was a result of high extinction ratio at cross port and low excess loss. We also demonstrated that the diameter of prestretched SMF to obtain high coupling efficiency was insensitive to the air hole diameter ratio to pitch of the PCF in the air hole collapsed SMF-PCF coupler.

  1. Design Topics for Superconducting RF Cavities and Ancillaries

    CERN Document Server

    Padamsee, H

    2014-07-17

    RF superconductivity has become a major subfield of accelerator science. There has been an explosion in the number of accelerator applications and in the number of laboratories engaged. The first lecture at this meeting of the CAS presented a review of fundamental design principles to develop cavity geometries to accelerate velocity-of-light particles (β = v/c ~ 1), moving on to the corresponding design principles for medium-velocity (medium-β) and low-velocity (low-β) structures. The lecture included mechanical design topics. The second lecture dealt with input couplers, higher-order mode extraction couplers with absorbers, and tuners of both the slow and fast varieties.

  2. High efficiency asymmetric directional coupler for slow light slot photonic crystal waveguides.

    Science.gov (United States)

    Xu, Yameng; Caer, Charles; Gao, Dingshan; Cassan, Eric; Zhang, Xinliang

    2014-05-05

    An asymmetric directional coupler scheme for the efficient injection of light into slow light slot photonic crystal waveguide modes is proposed and investigated using finite-difference time-domain simulation. Coupling wavelengths can be flexibly controlled by the geometrical parameters of a side-coupled subwavelength corrugated strip waveguide. This approach leads to a ~1dB insertion loss level up to moderately high light group indices (nG≈30) in wavelength ranges of 5-10nm. This work brings new opportunities to inject light into the slow modes of slot photonic crystal waveguides for on-chip communications using hybrid silicon photonics or sensing based on hollow core waveguides.

  3. An Integrated Photoluminescence Sensing Platform Using a Single-Multi-Mode Fiber Coupler-Based Probe

    Directory of Open Access Journals (Sweden)

    Feng Long

    2014-03-01

    Full Text Available We demonstrate an integrated fiber optic photoluminescence sensing platform using a novel single-multi-mode fiber coupler (SMFC-based probe with high collection efficiency for fluorescence signals. The SMFC, prepared using fused biconical taper technology, not only transmits excitation light, but also collects and transmits fluorescence. The entire system does not use complex optical components and rarely requires optical alignment. The simple structure of the SMFC considerably improves the light transmission efficiency, signal-to-noise ratio, and sensitivity of the system. Theoretical and experimental results show that the proposed probe increases the collection efficiency by more than eight-fold compared with a bifurcated fiber probe. The performance of the proposed probe was experimentally evaluated by measuring the fluorescence spectra of well-known targets and a fresh Tall Fescue leaf.

  4. An integrated photoluminescence sensing platform using a single-multi-mode fiber coupler-based probe.

    Science.gov (United States)

    Long, Feng; Zhu, Anna; Shi, Hanchang

    2014-03-21

    We demonstrate an integrated fiber optic photoluminescence sensing platform using a novel single-multi-mode fiber coupler (SMFC)-based probe with high collection efficiency for fluorescence signals. The SMFC, prepared using fused biconical taper technology, not only transmits excitation light, but also collects and transmits fluorescence. The entire system does not use complex optical components and rarely requires optical alignment. The simple structure of the SMFC considerably improves the light transmission efficiency, signal-to-noise ratio, and sensitivity of the system. Theoretical and experimental results show that the proposed probe increases the collection efficiency by more than eight-fold compared with a bifurcated fiber probe. The performance of the proposed probe was experimentally evaluated by measuring the fluorescence spectra of well-known targets and a fresh Tall Fescue leaf.

  5. Nonlinear effects in coplanar GaAs/InGaAs strained-layer superlattice directional couplers

    Science.gov (United States)

    Das, Utpal; Chen, YI; Bhattacharya, Pallab

    1987-01-01

    The performance characteristics of InGaAs/GaAs strained-layer superlattice coplanar ridge-type directional couplers realized by molecular beam epitaxy are reported. The measured power transfer characteristics with 1.15 micron incident photoexcitation demonstrate nonlinear coupling due to absorption associated with the tails of the excitonic resonances in the quantum wells. From a theoretical fit of the measured data, the nonlinear refractive index coefficient, n2, of the multiquantum well is found to be 2.25 x 10 to the -7th sq cm/W. This agrees very well with a value of n2 = 1.9 x 10 to the-7th sq cm/W obtained independently on the same material from interferometric measurents.

  6. High efficiency mode-locked, cylindrical vector beam fiber laser based on a mode selective coupler.

    Science.gov (United States)

    Wan, Hongdan; Wang, Jie; Zhang, Zuxing; Cai, Yu; Sun, Bin; Zhang, Lin

    2017-05-15

    We propose and demonstrate an all-fiber passively mode-locked laser with a figure-8 cavity, which generates pulsed cylindrical vector beam output based on a mode selective coupler (MSC). The MSC made of a two mode fiber and a standard single mode fiber is used as both the intracavity transverse mode converter and mode splitter with a low insertion loss of about 0.65 dB. The slope efficiency of the fiber laser is > 3%. Through adjusting the polarization state in the laser cavity, both radially and azimuthally polarized beams have been obtained with high mode purity which are measured to be > 94%. The laser operates at 1556.3 nm with a spectral bandwidth of 3.2 nm. The mode-locked pulses have duration of 17 ns and a repetition rate of 0.66 MHz.

  7. A superconducting 180° hybrid ring coupler for circuit quantum electrodynamics

    Science.gov (United States)

    Hoffmann, E.; Deppe, F.; Niemczyk, T.; Wirth, T.; Menzel, E. P.; Wild, G.; Huebl, H.; Mariantoni, M.; Weißl, T.; Lukashenko, A.; Zhuravel, A. P.; Ustinov, A. V.; Marx, A.; Gross, R.

    2010-11-01

    Superconducting circuit quantum electrodynamics experiments with propagating microwaves require devices acting as beam splitters. Using niobium thin films on silicon and sapphire substrates, we fabricated superconducting 180° microstrip hybrid ring couplers, acting as beam splitters with center frequencies of about 6 GHz. For the magnitude of the coupling and isolation, we find -3.5±0.5 dB and at least -15 dB, respectively, in a bandwidth of 2 GHz. We also investigate the effect of reflections at the superconductor-normal conductor contact by means of low temperature laser scanning microscopy. Our measurements show that our hybrid rings are well suited for on-chip applications in circuit quantum electrodynamics experiments.

  8. High Power Tm3+-Doped Fiber Lasers Tuned by a Variable Reflective Output Coupler

    Directory of Open Access Journals (Sweden)

    Yulong Tang

    2008-01-01

    Full Text Available Wide wavelength tuning by a variable reflective output coupler is demonstrated in high-power double-clad Tm3+-doped silica fiber lasers diode-pumped at ∼790  nm. Varying the output coupling from 96% to 5%, the laser wavelength is tuned over a range of 106  nm from 1949 to 2055  nm. The output power exceeds 20  W over 90-nm range and the maximum output power is 32  W at 1949  nm for 51-W launched pump power, corresponding to a slope efficiency of ∼70%. Assisted with different fiber lengths, the tuning range is expanded to 240  nm from 1866 to 2107  nm with the output power larger than 10  W.

  9. Improvement of grid frequency dynamic characteristic with novel wind turbine based on electromagnetic coupler

    DEFF Research Database (Denmark)

    You, Rui; Barahona, Braulio; Chai, Jianyun

    2017-01-01

    A synchronous generator is directly coupled to grid in the novel wind turbine drive train concept based on electromagnetic coupler (WT-EMC). Similarly to conventional power plants, WT-EMC has inherent (inertial) grid frequency support capability, albeit rather limited due to its configuration...... imbalance in the grid and then rapidly regulate the output power of WT-EMC. Based on the calculated electromagnetic torque of the synchronous generator in WT-EMC—acquired faster than the calculated grid frequency—the synchronous generator mechanical torque is controlled to track its electromagnetic...... torque to stabilize the rotor speed, therefore directly improving the grid frequency. The proposed control strategy effectiveness is firstly tested through simulations and then validated on a specially built experimental platform....

  10. Study of a superconducting spoke-type cavity and of its associated power coupler; Etude d'une cavite acceleratrice supraconductrice de type spoke et de son coupleur de puissance associe

    Energy Technology Data Exchange (ETDEWEB)

    Mielot, Ch

    2004-12-01

    This work deals with the study of a spoke-type cavity and its associated power coupler. The results of this study are used in the framework of the high power proton linear accelerator of the experimental accelerator-driven system project (XADS). The cavity (F=352 MHz, {beta}=0.35) was tested at 4 K and 2 K. The results at 4 K gave good margins toward XADS requirements that increase the reliability of a spoke based driver. At 2 K the accelerating field reached is the highest in the world for spoke cavities: 16 MV/M. The position and diameter of the coupling have been optimized in order to decrease the HF losses and avoid multi-factor risk. In order to decrease HF losses (taking into account the 20 kW power fed into the cavity) the electric coupling mode has been chosen. Different types of ceramic windows have been studied in order to make this critical point of the coupler reliable: coaxial disk with or without chokes or empty coaxial cylinder. The optimization process focused on the reflected power, the losses in the ceramic and the surface electric field. The risk with chokes has been modeled and studied with the propagation lines theory. A systematic study of the different windows has been done regarding the geometrical parameters. The disk without chokes seems to be a good solution for our application. The power source will be a solid state amplifier (for reliability and modularity reasons). An all over coaxial coupler can be designed and will be fabricated and tested soon. (author)

  11. Comentario: A la Presentación del Hombre de las Cavernas. De los Primeros Homínidos al Neanderthal

    Directory of Open Access Journals (Sweden)

    Gonzalo Correal Urrego

    2015-06-01

    Full Text Available

    Luego de la ponderada exposición del doctor Mendoza, en el corto espacio de que disponemos solo nos resta recapitular algunos de los aspectos más relevantes de su disertación y resumir algunos hitos que precedieron y otros que tuvieron continuidad luego de la aparición de Homo antecesor.

    Los hallazgos paleoantropológicos de las últimas décadas han sido muy importantes. Connotadosinvestigadores discuten en la actualidad si Sahelantropus Tchadensis, Orrin Tugenensis y Ardipithecus ramidus con una antigüedad que los aproxima a los 6 millones de años pueden ser considerados como precursores de los homínidos. Mientras se acrecientan las discusiones sobre los orígenes de los Homínidos, Meave Leakey cree que el fragmento de mandíbula de 5’600.000 años desenterrado en Lothagan, Kenya, en 1967 es el fósil de homínido más antiguo que se ha descubierto hasta hoy; otros hallazgos verificados en las postrimerías de los noventa corresponden a ejemplares del antiguo homínido Australopithecus afarensis descubierto por Donald Johansson, esqueleto que fuera bautizado con el nombre de Lucy.

    Procedente de Hadar, en Etiopía, su edad se calcula en 3´900.000 años. Testimonio silencioso del paso de legendarios primates, son las huellas de pisadas impresas en el fango de la ceniza volcánica de la llanura de Laetoli en Tanzania, y que han sido fechadas en 3’600.000 años. Una mandíbula exhumada en Tanzania por Mary Leaky, fue fechada en 3’500.000 años, y con los hallazgos de Turkana en 1994 el horizonte retrocede otros 600.000 años, con Australopitecus amanensis.

    Hoy se conocen cinco especies de Australopithecus, algunos como Australopithecus garghi elaboraron artefactos líticos muy rudimentarios.

  12. Evaluación de la inmunogenicidad y la capacidad protectora homóloga de un candidato vacunal tetravalente de Leptospira, para uso veterinario

    OpenAIRE

    Yaritza Cuba-Romero; Noemi Gainza-Santos; Alfredo Saltaren-Cobas; Mariela Naranjo-Medina

    2016-01-01

    La inmunogenicidad es un parámetro importante en estudios de inmunógenos. En la leptospirosis la respuesta inmune humoral es vital para la resistencia a la infección, de ahí que este trabajo se haya propuesto evaluar la inmunogenicidad y la capacidad protectora homóloga de un candidato tetravalente que incluye al serogrupo Ballum en su formulación. Se trabajó con la cepa 245-12 clasificada como L. borgpetersenii serovar Ballum, aislada a partir de un caso confirmado de leptospirosis. Con esta...

  13. Les points d’articulation entre homéopathie et oncologie conventionnelle Connecting Homeopathy and Conventional Oncology. An ethnographic investigation with practitioners and patients in Brussels

    Directory of Open Access Journals (Sweden)

    Olivier Schmitz

    2011-06-01

    Full Text Available De nombreuses études ont montré que la prévalence du recours à des médecines non conventionnelles était plus importante chez les malades atteints de cancers que dans toute autre catégorie de malades. Les caractéristiques de la maladie, les incertitudes de son évolution, de même que les effets de ses traitements sont autant de facteurs qui poussent les malades à emprunter des voies non conventionnelles. Parmi celles-ci, l’homéopathie est couramment utilisée, et jouit d’une bonne réputation pour répondre à certains besoins des malades que l’oncologie conventionnelle laisse de côté. Cet article vise à éclairer ce que les traitements homéopathiques ont à offrir à cette catégorie de malades, et sous quelle forme ces traitements s’articulent avec les traitements oncologiques. Le matériau analysé porte sur une vingtaine d’entretiens ethnographiques réalisés auprès de malades du cancer ayant recours à l’homéopathie. Certains éléments de l’organisation de ses traitements, de même que les observances et les représentations qui leur sont associées font de l’homéopathie un système thérapeutique pouvant apporter un certain soutien aux malades dans la lutte contre l’angoisse et l’incertitude que suscitent invariablement la maladie cancéreuse et ses traitements.Several studies have revealed a greater unconventional medicines usage rate in people living with cancer than by other patient categories. The characteristics of cancer, the uncertainties about its evolution as well as the side effects of its treatments are reasons pushing patients toward unconventional therapies. Among these, homeopathy is frequently used. It benefits from a good reputation in the management of some cancer patients’ needs partly ignored by conventional oncology treatments. This exploratory article aims to enlighten what homeopathy treatments can offer to cancer patients, and the way those treatments are combined with

  14. Higher Order Mode Filter Design for Double Quarter Wave Crab Cavity for the LHC High Luminosity Upgrade

    CERN Document Server

    Xiao, B P; Ben-Zv, I; Burt, Graeme Campbell; Calaga, Rama; Capatina, Ofelia; Hall, B; Jones, T; Skaritka, J; Verdú-Andrés, S; Wu, Q

    2015-01-01

    A Double Quarter Wave Crab Cavity (DQWCC) was designed for the Large Hadron Collider (LHC) luminosity upgrade. A compact Higher Order Mode (HOM) filter with wide stop band at the deflecting mode is developed for this cavity. Multi-physics finite element simulation results are presented. The integration of this design to the cavity cryomodule is described.

  15. El papel de los juegos en la transmisión cultural: los poemas homéricos y las Olimpiadas en la sociedad oral griega

    Directory of Open Access Journals (Sweden)

    Cantarero, Luis

    2006-12-01

    Full Text Available The author calls attention to the role played by the games in Greek oral tradition. After introducing the most general and defining traits of the games, he argues that those described in the Homeric Poems and practiced in Classical Greece —the Olympian, Pythian, Isthmian and Nemean Games— had two main functions: to provide entertainment and to construct a social order. This social order was epitomized in the values of the Homeric, Olimpian hero: noble, sportsman and amateur.

    La intención de este trabajo es revelar el papel de los juegos en la cultura oral griega. A modo de introducción, resumimos los rasgos más generales y característicos. Una vez situados en ese contexto general, veremos que los juegos descritos en los poemas homéricos y los que se realizaban en la Grecia clásica —Olímpicos, Píticos, Ístmicos y Nemeos— tenían dos funciones primordiales: proporcionar entretenimiento y construir un orden social; orden que, como mostramos aquí, venía sintetizado por los valores que aglutinaba el héroe homérico y olímpico: el noble-deportista-amateur.

  16. Efficiently Harvesting Sun Light for Silicon Solar Cells through Advanced Optical Couplers and A Radial p-n Junction Structure

    Directory of Open Access Journals (Sweden)

    Hsin-Cheng Lee

    2010-04-01

    Full Text Available Silicon-based solar cells (SCs promise to be an alternative energy source mainly due to: (1 a high efficiency-to-cost ratio, (2 the absence of environmental-degradation issues, and (3 great reliability. Transition from wafer-based to thin-film SC significantly reduces the cost of SCs, including the cost from the material itself and the fabrication process. However, as the thickness of the absorption (or the active layer decreases, the energy-conversion efficiency drops dramatically. As a consequence, we discuss here three techniques to increase the efficiency of silicon-based SCs: (1 photonic crystal (PC optical couplers and (2 plasmonic optical couplers to increase efficiency of light absorption in the SCs, and (3 a radial p-n junction structure, decomposing light absorption and diffusion path into two orthogonal directions. The detailed mechanisms and recent research progress regarding these techniques are discussed in this review article.

  17. Wavelength and bandwidth-tunable silicon comb filter based on Sagnac loop mirrors with Mach-Zehnder interferometer couplers.

    Science.gov (United States)

    Jiang, Xinhong; Wu, Jiayang; Yang, Yuxing; Pan, Ting; Mao, Junming; Liu, Boyu; Liu, Ruili; Zhang, Yong; Qiu, Ciyuan; Tremblay, Christine; Su, Yikai

    2016-02-08

    We propose and experimentally demonstrate a wavelength and bandwidth-tunable comb filter based on silicon Sagnac loop mirrors (SLMs) with Mach-Zehnder interferometer (MZI) couplers. By thermally tuning the MZI couplers in common and differential modes, the phase shift and reflectivity of the SLMs can be changed, respectively, leading to tunable wavelength and bandwidth of the comb filter. The fabricated comb filter has 93 comb lines in the wavelength range from 1535 nm to 1565 nm spaced by ~0.322 nm. The central wavelength can be red-shifted by ~0.462 nm with a tuning efficiency of ~0.019 nm/mW. A continuously tunable bandwidth from 5.88 GHz to 24.89 GHz is also achieved with a differential heating power ranging from 0.00 mW to 0.53 mW.

  18. Slim elliptical cavity at 800 MHz for local crab crossing

    CERN Document Server

    Ficcadenti, L

    2011-01-01

    A slim highly eccentric elliptical Crab cavity with vertical deflection at 800 MHz, compatible to beam line distances everywhere in the LHC ring, was designed. It is a good fall-back solution in case of problems with new compact 400 MHz designs. Simulated RF characteristics of the deflecting mode, HOM spectra and damping, tuning and multipacting effects are presented. First the most simple HOM coupling system from a point of view of geometry, machining and cleaning was investigated. The rejection of the working mode of such coupler depend on very tight mechanical tollerances. To overcome this issue a notch filter was added to the design. Results of both cases will be presented.

  19. Analytical Study on Propagation Dynamics of Optical Beam in Parity-Time Symmetric Optical Couplers

    Science.gov (United States)

    Zhou, Zheng; Zhu, Bo; Zhang, Li-Juan

    2015-04-01

    We present exact analytical solutions to parity-time (PT) symmetric optical system describing light transport in PT-symmetric optical couplers. We show that light intensity oscillates periodically between two waveguides for unbroken PT-symmetric phase, whereas light always leaves the system from the waveguide experiencing gain when light is initially input at either waveguide experiencing gain or waveguide experiencing loss for broken PT-symmetric phase. These analytical results agree with the recent experimental observation reported by Rüter et al. [Nat. Phys. 6 (2010) 192]. Besides, we present a scheme for manipulating PT symmetry by applying a periodic modulation. Our results provide an efficient way to control light propagation in periodically modulated PT-symmetric system by tuning the modulation amplitude and frequency. Supported by the National Natural Science Foundation of China under Grant No. 11465008, the Hunan Provincial Natural Science Foundation under Grant Nos. 2015JJ4020 and 2015JJ2114, the Scientific Research Fund of Hunan Provincial Education Department under Grant No. 14A118

  20. Analysis and comparison between electric and magnetic power couplers for accelerators in Free Electron Lasers (FEL)

    Energy Technology Data Exchange (ETDEWEB)

    Serpico, C., E-mail: claudio.serpico@elettra.eu [Elettra - Sincrotrone Trieste, Trieste (Italy); Grudiev, A. [CERN, Geneva (Switzerland); Vescovo, R. [University of Trieste, Trieste (Italy)

    2016-10-11

    Free-electron lasers represent a new and exciting class of coherent optical sources possessing broad wavelength tunability and excellent optical-beam quality. The FERMI seeded free-electron laser (FEL), located at the Elettra laboratory in Trieste, is driven by a 200 m long, S-band linac: the high energy part of the linac is equipped with 6 m long backward traveling wave (BTW) structures. The structures have small iris radius and a nose cone geometry which allows for high gradient operation. Development of new high-gradient, S-band accelerating structures for the replacement of the existing BTWs is under consideration. This paper investigates two possible solutions for the RF power couplers suitable for a linac driven FEL which require reduced wakefields effects, high operating gradient and very high reliability. The first part of the manuscript focuses on the reduction of residual field asymmetries, while in the second analyzes RF performances, the peak surface fields and the expected breakdown rate. In the conclusion, two solutions are compared and pros and cons are highlighted.

  1. Nanophotonic lab-on-a-chip platforms including novel bimodal interferometers, microfluidics and grating couplers.

    Science.gov (United States)

    Duval, Daphné; González-Guerrero, Ana Belén; Dante, Stefania; Osmond, Johann; Monge, Rosa; Fernández, Luis J; Zinoviev, Kirill E; Domínguez, Carlos; Lechuga, Laura M

    2012-05-08

    One of the main limitations for achieving truly lab-on-a-chip (LOC) devices for point-of-care diagnosis is the incorporation of the "on-chip" detection. Indeed, most of the state-of-the-art LOC devices usually require complex read-out instrumentation, losing the main advantages of portability and simplicity. In this context, we present our last advances towards the achievement of a portable and label-free LOC platform with highly sensitive "on-chip" detection by using nanophotonic biosensors. Bimodal waveguide interferometers fabricated by standard silicon processes have been integrated with sub-micronic grating couplers for efficient light in-coupling, showing a phase resolution of 6.6 × 10(-4)× 2π rad and a limit of detection of 3.3 × 10(-7) refractive index unit (RIU) in bulk. A 3D network of SU-8 polymer microfluidics monolithically assembled at the wafer-level was included, ensuring perfect sealing and compact packaging. To overcome some of the drawbacks inherent to interferometric read-outs, a novel all-optical wavelength modulation system has been implemented, providing a linear response and a direct read-out of the phase variation. Sensitivity, specificity and reproducibility of the wavelength modulated BiMW sensor has been demonstrated through the label-free immunodetection of the human hormone hTSH at picomolar level using a reliable biofunctionalization process.

  2. Design of a Ku band miniature multiple beam klystron

    Energy Technology Data Exchange (ETDEWEB)

    Bandyopadhyay, Ayan Kumar, E-mail: ayan.bandyopadhyay@gmail.com; Pal, Debasish; Kant, Deepender [Microwave Tubes Division, CSIR-CEERI, Pilani, Rajasthan-333031 (India); Saini, Anil; Saha, Sukalyan; Joshi, Lalit Mohan

    2016-03-09

    The design of a miniature multiple beam klystron (MBK) working in the Ku-band frequency range is presented in this article. Starting from the main design parameters, design of the electron gun, the input and output couplers and radio frequency section (RF-section) are presented. The design methodology using state of the art commercial electromagnetic design tools, analytical formulae as well as noncommercial design tools are briefly presented in this article.

  3. A Comprehensive Computational Design for Microstrip Passive and Active Linear Circuits

    Directory of Open Access Journals (Sweden)

    El-Sayed A. El-Badawy

    2012-08-01

    Full Text Available In this paper, a complete program called HHSS2 is introduced which is a user-oriented program capable of designing linear active and passive microstrip circuits such as amplifiers, oscillators, mixers, lowpass filters, and couplers. The substrate parameters and the characteristic impedance of the microstrip lines are given to the program as a common statement. Examples for the design of a 3-GHz high gain amplifier, 2.6-GHz oscillator, ring coupler operated at 3.33 GHz, Lange coupler operated at 3.3 GHz, and maximally-flat lowpass filter operated at 2 GHz with 0.75 GHz cutoff frequency are introduced.    Key Words: Computational Microstrip Circuit Design, Microwave Circuits, Computer Aided Design.

  4. Contribución al conocimiento de las interacciones entre plantas, hormigas y homópteros en bosques secos de Colombia

    Directory of Open Access Journals (Sweden)

    Ramírez Mónica

    2001-12-01

    Full Text Available Las interacciones entre plantas y hormigas y entre plantas, hormigas y homópteros se estudiaron en 248 estaciones de muestreo situadas en nueve fragmentos de bosque seco del valle geográfico del río Cauca, entre enero y junio de 1997. Se registraron 352 interacciones que involucran 91 especies vegetales, hormigas de 67 especies y homópteros pertenecientes a nueve familias. El 4 7% de las asociaciones registradas implica el uso por parte de las hormigas de diferentes estructuras de las plantas (p. e. raíces de las epífitas, domacios en los tallos, hojarasca acumulada entre ramas y hojas, brácteas y peciolos de Heliconia spp. como refugios temporales o sitios de anidamiento. El restante 53% involucra la recolección de miel de homópteros y de sustancias azucaradas en nectarios extraflorales. asmannia auropunctata (17%, Dolichoderus bispinosus (11% Y Brachymyrmex heeri (7% fueron las especies de hormigas registradas con mayor frecuencia. Las plantas más utilizadas fueron Heliconia stricta (8%, Philodendron sp. nov. (7% y Passiflora coriacea (5%. Entre las relaciones observadas, predominan las de tipo generalista, en que las hormigas explotan diferentes recursos aparentemente en forma oportunista y las plantas pueden encontrarse en buen estado a pesar de la ausencia de las hormigas.Interactions between ants and plants and those involving homopterans were studied in 248 sampling points located within nine tropical decidous forest fragments in the Cauca river Valley, between january and june, 1997. A total of 352 interactions were recorded involving 91 plant species, 67 ant species and Homoptera belonging to nine families. 47% ofthe interactions involved ants using different plant structures (such as epiphyte roots, domacia, litter collected in branches and leaves, bracts and petioles of Heliconia spp. as nesting sites or temporary refugia. The remaining 53% involved the collection of homopteran honeydew and sugary substances from extrafloral

  5. Calculation of Wakefields and Higher Order Modes for the New Design of the Vacuum Chamber of the ALICE Experiment for the HL-LHC

    CERN Document Server

    Wanzenberg, Rainer; CERN. Geneva. ATS Department

    2016-01-01

    The High Luminosity Large Hadron Collider (HL-LHC) project was started with the goal to extend the discovery potential of the Large Hadron Collider (LHC). The HL-LHC study implies also an upgraded dimensions of the ALICE beam pipe. The trapped monopole and dipole Higher Order Modes (HOMs) and the short range wakefields for the new design of the ALICE vacuum chamber were calculated with help of the computer codes MAFIA and ECHO2D. The results of the short range wakefields calculations and the HOMs calculations for the ALICE vacuum chamber with new dimensions are presented in this report. The short range wakefields are presented in terms of longitudinal and transverse wake potentials and also in terms of loss and kick parameters. The frequency, the loss parameter, the R/Q and the Qvalues and also power loss parameters are presented as result of the HOMs calculations and can be converted into impedance values.

  6. Les Amours d’Arès et Aphrodite, la critique homérique et la pantomime dans l’Ars amatoria

    OpenAIRE

    Jean-Christophe Jolivet

    2010-01-01

    Le traitement de l'épisode des Amours d'Arès et Aphrodite dans le chant 2 de l'Ars amatoria laisse supposer que les commentaires homériques ont exercé une influence sur la version ovidienne, non seulement quant à l'interprétation didactique du mythe, mais également du fait que le chant de Démodocos était considéré par certains interprètes comme l'illustration archaïque d'un registre comique et érotique. Par ailleurs, un certain nombre d'indices laissent supposer une référence à la pantomime d...

  7. Further clarification on the Hom, Mitchell, Lee, and Griffeth (2012) model: Reply to Bergman, Payne, and Boswell (2012) and Maertz (2012).

    Science.gov (United States)

    Griffeth, Rodger W; Lee, Thomas W; Mitchell, Terence R; Hom, Peter W

    2012-09-01

    In this article, we reply to Bergman, Payne, and Boswell (2012) and Maertz (2012), who commented on our reconceptualization of the employee turnover criterion and proximal withdrawal states (Hom, Mitchell, Lee, & Griffeth, 2012). We agree with some points (e.g., anticipated destinations) but take issue with others (e.g., turnover intentions as the criterion). Nonetheless, our aim is to clarify our integrative formulation about mindsets for organizational participation and withdrawal. In our view, the current process of "article-commentaries-reply" advances our collective understanding of staying and leaving, which is of longstanding interest to scholars in industrial and organizational psychology, organizational behavior, and human resource management. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

  8. L’analyse de la création homérique dans les scholia vetera à l’Iliade1

    OpenAIRE

    Bréchet, Christophe

    2014-01-01

    Quand, à la fin de mon année de Licence à l’université de Nanterre (1998), je demandai à Suzanne Saïd de diriger mon mémoire de maîtrise, elle me proposa deux sujets : l’image de Troie à l’époque impériale ou la critique littéraire, à partir du De audiendis poetis de Plutarque. La lecture de ce traité m’incita finalement à étudier les citations d’Homère dans l’œuvre de Plutarque. Je bénéficiai des conseils de Suzanne Saïd non seulement pendant ma maîtrise, qu’elle dirigea, mais tout au long d...

  9. Gestação obtida em coelha após ooforectomia bilateral e transplante ovariano homógeno

    Directory of Open Access Journals (Sweden)

    Andy Petroianu

    Full Text Available OBJETIVO: Verificar a possibilidade de fertilização natural após ooforectomia total bilateral e transplante ovariano homógeno ortotópico sem anastomose vascular e imunossuprimidos pela ciclosporina. MÉTODO: Foram utilizadas dez coelhas da raça Nova Zelândia Branca e Califórnia. Realizou-se ooforectomia total bilateral e transplante ortotópico dos ovários entre pares de animais. De um lado, foi transplantado o ovário íntegro e de outro, o ovário fatiado. Não houve anastomose vascular. A imunossupressão se deu com a administração ciclosporina através de tubo orogástrico diariamente, durante seis meses. Três meses depois, as fêmeas foram colocadas diariamente para copular com machos sabidamente férteis da raça Nova Zelândia Branca, por outros seis meses. No final do período do experimento, foram realizadas dosagens de estradiol, progesterona, hormônio folículo estimulante e hormônio luteinizante, além de estudo histológico dos ovários, tubas e úteros. RESULTADOS: Gravidezes ocorreram em cinco coelhas, sendo que, em quatro delas, houve nascimento de filhotes. As dosagens hormonais estiveram dentro da faixa de normalidade em todos os animais. Os ovários transplantados estavam rodeados de tecido conjuntivos, bem vascularizados e com folículos ovarianos em vários estádios de desenvolvimento. CONCLUSÕES: Obteve-se, com sucesso, a fertilização natural e manutenção hormonal feminina em coelhas submetidas a transplante homógeno de tecido ovariano sem anastomose vascular e imunossuprimidos pela ciclosporina.

  10. Evaluación de la inmunogenicidad y la capacidad protectora homóloga de un candidato vacunal tetravalente de Leptospira, para uso veterinario

    Directory of Open Access Journals (Sweden)

    Yaritza Cuba-Romero

    2016-12-01

    Full Text Available La inmunogenicidad es un parámetro importante en estudios de inmunógenos. En la leptospirosis la respuesta inmune humoral es vital para la resistencia a la infección, de ahí que este trabajo se haya propuesto evaluar la inmunogenicidad y la capacidad protectora homóloga de un candidato tetravalente que incluye al serogrupo Ballum en su formulación. Se trabajó con la cepa 245-12 clasificada como L. borgpetersenii serovar Ballum, aislada a partir de un caso confirmado de leptospirosis. Con esta cepa previamente caracterizada desde el punto de vista de su virulencia, se formularon 5 lotes de una preparación vacunal tetravalente, la cual contiene además las cepas Canicola, Icterohaemorrhagiae y Pomona contenidas en la vacuna Polivalente-Leptospira, de uso veterinario. Se evaluó la inmunogenicidad de esta preparación, mediante microaglutinación y la capacidad de protección homóloga en hámster sirio dorado, frente al reto con 100 DL50. Los animales se inmunizaron con dos dosis de la vacuna (0,1mL con un intervalo de 15 días, el reto se llevó a cabo a los 14 días de concluido el esquema de inmunización. Los resultados obtenidos se compararon con los de la vacuna Polivalente-Leptospira. Todos los lotes de preparación tetravalente formulados cumplieron satisfactoriamente con los controles de calidad. Los lotes formulados en este estudio mostraron una significativa inmunogenicidad y capacidad de protección homologa frente al serogrupo Ballum, y lograron eliminar el estado de portador en los animales inmunizados. El presente trabajo, por primera vez, sienta las bases para formulaciones vacunales novedosas, en animales, conteniendo el serogrupo Ballum.

  11. Alterações histológicas em enxerto de osso homógeno preparado e armazenado com duas técnicas diferentes

    Directory of Open Access Journals (Sweden)

    Duarte da Silva Alfredo Benjamin

    2000-01-01

    Full Text Available Esta pesquisa analisa as alterações histológicas de enxerto ósseo homógeno preparado de diferentes modos. Em um grupo, ossos metatársicos-l de ratos foram armazenados a -70° Celsius e em outro grupo, os ossos foram descalcificados e estocados em temperatura ambiente após terem sido liofilizados. Esses ossos foram enxertados nas regiões inguinais de ratos e retirados para estudo histológico no trigésimo dia de pós-operatório. Macroscopicamente os ossos não descalcificados e armazenados a -70°C estavam envoltos por uma cápsula delgada, facilmente desprendida e apresentavam consistência de osso cortical. Microscopicamente observou-se absorção da superfície endostal com diminuição da camada cortical e aumento da cavidade medular. A cortical estava sofrendo processo de reabsorção e a superfície óssea externa possuía uma cápsula fibrosa delgada e células inflamatórias. Os ossos descalcificados e liofilizados, na macroscopia, apresentavam-se de consistência amolecida e estavam envoltos por uma cápsula espessa e firmemente aderida. Microscopicamente, a maior parte da arquitetura óssea estava preenchida por material acelular e avascular, muito semelhante à cartilagem e envolvendo o tecido, uma cápsula fibrosa espessa com células inflamatórias. Portanto, existiam diferenças histológicas dos enxertos ósseos homógenos, dependendo do preparo e do armazenamento do osso.

  12. All fiber nonlinear microscopy at 1550 nm using a double-clad fiber coupler

    Science.gov (United States)

    Perrillat-Bottonet, Thomas; Strupler, Mathias; Leduc, Mikael; Majeau, Lucas; Godbout, Nicolas; Boudoux, Caroline

    2017-02-01

    Nonlinear microscopy has already shown its impact in biological research, namely in the fields of neurobiology, immunology, cancer research and embryology. Typically, these microscopes operate under free space propagation, using a dichroic mirror to separate the nonlinear signals from the excitation laser. While powerful such implementations are difficult to translate from the laboratory to a clinical setting where the environment is less controlled. Therefore, we propose an alignment-free all-fiber nonlinear microscopy system at 1550 nm based on double-clad fibers (DCF). As sectioning is performed through nonlinear effects, nonlinear microscopy does not require a detection pinhole, and. the DCF inner cladding can be used for efficient collection of nonlinear signals. The built system allows for multiplexing second harmonic generation (SHG) and two-photon excitation fluorescence (2PEF), collected from the inner cladding; and reflectance confocal microscopy (RCM), detected from the core acting as the confocal pinhole. Finally, an asymmetric double-clad fiber coupler (DCFC) is used to address efficiently both DCF channels. This all-fiber system is more compact and less sensitive to alignment, but requires carefully managing the transmission of the femtosecond pulse in the fiber. This is addressed using dispersion compensation fiber, pulse compression and solitonic propagation. Additionally, with a source centered at 1550 nm, we benefit from reduced sample scattering thus increasing the depth of field in comparison with systems operating at 800 nm. Overall we believe that the developed system could be transferred in clinics to enable in-vivo and in-situ imaging of human patient.

  13. Photonic crystal fiber design for broadband directional coupling

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Bang, Ole; Bjarklev, Anders Overgaard

    2004-01-01

    A novel design for a broadband directional coupler based on a photonic crystal fiber is investigated numerically. It is shown that suitable index-depressing doping of the core regions in an index-guiding twin-core photonic crystal fiber can stabilize the coupling coefficient between the cores ove...... an extremely broad (octave-spanning) frequency range....

  14. A Novel Wind Turbine Concept Based on an Electromagnetic Coupler and the Study of Its Fault Ride-through Capability

    DEFF Research Database (Denmark)

    You, Rui; Barahona Garzón, Braulio; Chai, Jianyun

    2013-01-01

    and grid voltage support capability can be significantly improved. An electromagnetic coupling speed regulating device (EMCD) is used to connect the gearbox high speed shaft and synchronous generator rotor shaft, transmitting torque to the synchronous generator, while decoupling the gearbox side...... and the synchronous generator, so the synchronous generator torque oscillations during a grid fault are not transmitted to the gearbox. The EMCD is composed of an electromagnetic coupler and a one quadrant operation converter with reduced capability and low cost. A control strategy for the new wind turbine...

  15. Mode division multiplexing coupler of four LP modes based on a five-core microstructured optical fiber

    Science.gov (United States)

    Zhang, Hongwei; Liu, Yange; Wang, Zhi; Han, Ya; Yang, Kang; Yu, Jie

    2018-03-01

    An all-fiber mode division multiplexing coupler based on a five-core microstructured optical fiber is proposed to multiplex or demultiplex LP11, LP21, LP02 and LP01 modes simultaneously. The five-core microstructured optical fiber is composed of a few mode core supporting the four LP modes propagating at 1550 nm and four single-mode cores surrounding the few-mode core. The coupling mechanism between LP01 mode in each single-mode core and the corresponding four LP modes in the few-mode core is based on avoid-crossing effect. Numerical simulation results show that coupling bandwidths of LP11, LP21, LP02 and LP01 mode are 115 nm, 56 nm, 30 nm, 46 nm respectively, with a coupling length of 2156.1 μm. The proposed mode division multiplexing coupler can multiplex or demultiplex four LP modes simultaneously with large operation bandwidth, making it a good candidate for space-division multiplexing system.

  16. New configurations for high-efficiency prism couplers with application to GeO2 optical waveguides.

    Science.gov (United States)

    Yin, Z Y; Garside, B K

    1983-04-01

    A new prism coupler configuration is described which is very simple and reproducible. This device has been used to couple an Ar laser beam into a TEO single-mode GeO2 thin film waveguide with efficiencies exceeding 92%. Two specific air gap profiles using only one ball bearing and two sets of aluminum films have been examined.The theoretical description and experimental performance of this new type of prism coupler are presented; in both cases the air gap profiles are very close to the theoretically optimum shape, especially for a gap which does not have a mechanical contact point near the input optical beam incidence point on the waveguide. This approach is particularly advantageous for use with a fragile or soft thin film waveguide, since surface damage can more easily be avoided. Theoretical coupling efficiencies of 96.4 and 98.8% are predicted for the particular experimental samples investigated, and measured values of 90 and 92% have been achieved.

  17. ¿Promueven las regiones cromosómicas específicas el apareamiento, sinapsis y recombinación de los cromosomas homólogos en meiosis?

    OpenAIRE

    Valenzuela Martínez, Nohelia

    2012-01-01

    La meiosis es un tipo especializado de división celular que permite a los organismos con reproducción sexual producir gametos haploides y, por tanto, mantener su número cromosómico generación tras generación. La reducción del número cromosómico depende de la formación de bivalentes entre los pares de cromosomas homólogos en profase I y su posterior segregación en anafase I. La formación de bivalentes se produce como consecuencia del apareamiento, sinapsis y recombinación de los cromosomas hom...

  18. Helicobacter pylori bab Paralog Distribution and Association with cagA, vacA, and homA/B Genotypes in American and South Korean Clinical Isolates.

    Directory of Open Access Journals (Sweden)

    Aeryun Kim

    Full Text Available Helicobacter pylori genetic variation is a crucial component of colonization and persistence within the inhospitable niche of the gastric mucosa. As such, numerous H. pylori genes have been shown to vary in terms of presence and genomic location within this pathogen. Among the variable factors, the Bab family of outer membrane proteins (OMPs has been shown to differ within subsets of strains. To better understand genetic variation among the bab genes and to determine whether this variation differed among isolates obtained from different geographic locations, we characterized the distribution of the Bab family members in 80 American H. pylori clinical isolates (AH and 80 South Korean H. pylori clinical isolates (KH. Overall, we identified 23 different bab genotypes (19 in AH and 11 in KH, but only 5 occurred in greater than 5 isolates. Regardless of strain origin, a strain in which locus A and locus B were both occupied by a bab gene was the most common (85%; locus C was only occupied in those isolates that carried bab paralog at locus A and B. While the babA/babB/- genotype predominated in the KH (78.8%, no single genotype could account for greater than 40% in the AH collection. In addition to basic genotyping, we also identified associations between bab genotype and well known virulence factors cagA and vacA. Specifically, significant associations between babA at locus A and the cagA EPIYA-ABD motif (P<0.0001 and the vacA s1/i1/m1 allele (P<0.0001 were identified. Log-linear modeling further revealed a three-way association between bab carried at locus A, vacA, and number of OMPs from the HOM family (P<0.002. En masse this study provides a detailed characterization of the bab genotypes from two distinct populations. Our analysis suggests greater variability in the AH, perhaps due to adaptation to a more diverse host population. Furthermore, when considering the presence or absence of both the bab and homA/B paralogs at their given loci and the

  19. Implante de condrócitos homólogos em defeitos osteocondrais de cães: padronização da técnica e avaliação histopatológica

    Directory of Open Access Journals (Sweden)

    L.S. Iamaguti

    2013-02-01

    Full Text Available Padronizou-se a metodologia para cultura de condrócitos em cães e avaliou-se seu implante em lesões osteocondrais, utilizando-se a membrana biossintética de celulose (MBC como revestimento. Dez cães, adultos e clinicamente sadios, foram submetidos à artrotomia das articulações fêmoro-tíbio-patelares. Defeitos de 4mm de diâmetro e profundidade foram induzidos no sulco troclear de ambos os membros. MBC foi aplicada na base e na superfície das lesões. Os defeitos do membro direito foram preenchidos com condrócitos homólogos cultivados formando o grupo-tratado (GT; os do membro esquerdo, sem implante celular, foram designados grupo-controle (GC. A evolução pós-operatória foi analisada com especial interesse nos processos de reparação da lesão, por meio de histomorfometria e imuno-histoquímica para colágeno tipo II e sulfato de condroitina. A cultura de condrócitos homólogos apresentou alta densidade e taxa de viabilidade. Observou-se integridade do tecido neoformado com a cartilagem adjacente na avaliação histológica, em ambos os grupos. Na imuno-histoquímica, verificou-se predomínio de colágeno tipo II no GT. Morfometricamente, não houve diferença significativa entre o tecido fibroso e o fibrocartilaginoso entre os grupos. A cultura de condrócitos homólogos de cães foi exequível. O tecido neoformado apresentou qualidade discretamente superior associado ao implante homólogo de condrócitos, contudo não promoveu reparação por cartilagem hialina.

  20. Unicistes versus pluralistes : l'homéopathie brésilienne à l'ère de la globalisation Unicists versus Pluralists: Brazilian Homeopathy in the Age of Globalization

    Directory of Open Access Journals (Sweden)

    Armelle Giglio-Jacquemot

    2011-11-01

    Full Text Available La globalisation représente pour les entreprises un cadre particulièrement propice à la circulation de leurs marchandises et à l'expansion de leurs marchés. Au Brésil, l'installation récente d'une filiale des Laboratoires français Boiron ébranle le champ local de l'homéopathie. A partir d'éléments de terrain recueillis à São Paulo, l'article se propose d'examiner les réactions, stratégies et changements suscités par cette implantation dans le champ de l'homéopathie brésilienne mais aussi au-delà. Il se penche également sur les adaptations auxquelles cette industrie pharmaceutique, porteuse d'une certaine conception de l'homéopathie et du médicament homéopathique, se voit localement contrainte pour distribuer ses produits.For firms, globalization represents a propitious framework for the circulation of merchandise and market expansion. In Brazil, the recent establishment of a subsidiary of the French laboratory Boiron has shaken the local field of homeopathy. Based on ethnographic fieldwork in São Paulo, this article particularly examines the reactions, strategies and changes caused by this implantation in Brazilian homeopathy and beyond. The study also looks into the way this pharmaceutical industry - which bears a certain conception of homeopathy and of homeopathic drugs - has had to adapt in order to distribute its products locally.

  1. Comparison of Measured and Calculated Coupling between a Waveguide and an RF Cavity Using CST Microwave Studio

    Energy Technology Data Exchange (ETDEWEB)

    J. Shi; H. Chen; S. Zheng; D. Li; R.A. Rimmer; H. Wang

    2006-06-26

    Accurate predications of RF coupling between an RF cavity and ports attached to it have been an important study subject for years for RF coupler and higher order modes (HOM) damping design. We report recent progress and a method on the RF coupling simulations between waveguide ports and RF cavities using CST Microwave Studio in time domain (Transit Solver). Comparisons of the measured and calculated couplings are presented. The simulated couplings and frequencies agree within {approx} 10% and {approx} 0.1% with the measurements, respectively. We have simulated couplings with external Qs ranging from {approx} 100 to {approx} 100,000, and confirmed with measurements. The method should also work well for higher Qs, and can be easily applied in RF power coupler designs and HOM damping for normal-conducting and superconducting cavities.

  2. Two-dimensional Ag/SiO2 and Cu/SiO2 nanocomposite surface-relief grating couplers and their vertical input coupling properties

    Science.gov (United States)

    Wang, Jun; Mu, Xiaoyu; Wang, Gang; Liu, Changlong

    2017-11-01

    By etching two SiO2 optical waveguide slabs separately implanted with 90 keV Ag ions and 60 keV Cu ions at the same dose of 6 × 1016 cm-2, two-dimensional Ag/SiO2 and Cu/SiO2 nanocomposite surface-relief grating couplers with 600-nm periodicity and 100-nm thickness were fabricated, and their structural and vertical input coupling properties were investigated. Experimental results revealed that the two couplers could convert light beams at wavelengths of 620-880 nm into guided waves with different efficiencies, highlighting the special importance of metal nanoparticles (NPs). Further discussions also revealed that owing to the introduction of periodically distributed metal NPs, the periodical phase modification of the transmitted beam was enhanced drastically, and the nanocomposite veins could behave as efficient light scatterers. As a result, the two couplers were much larger in coupling efficiency than the NP-free one with identical morphological parameters. The above findings may be useful to construct thin and short but efficient surface-relief grating couplers on glass optical waveguides.

  3. On-chip grating coupler array on the SOI platform for fan-in/fan-out of MCFs with low insertion loss and crosstalk

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ye, Feihong; Peucheret, Christophe

    2015-01-01

    for the grating couplers and the introduction of an aluminum reflective mirror, a highest coupling efficiency of -3.8 dB with 3 dB coupling bandwidth of 48 nm and 1.5 dB bandwidth covering the whole C band, together with crosstalk lower than -32 dB are demonstrated. (C)2015 Optical Society of America...

  4. HOM Choice Study with Test Electronics for Use as beam Position Diagnostics in 3.9 GHz Accelerating Cavities in FLASH

    CERN Document Server

    Baboi, N; Zhang, P; Eddy, N; Fellenz, B; Wendt, M

    2012-01-01

    Higher Order Modes (HOM) excited by the beam in the 3.9 GHz accelerating cavities in FLASH can be used for beam position diagnostics, as in a cavity beam position monitor. Previous studies of the modal choices within the complicated spectrum have revealed several options: cavity modes with strong coupling to the beam, and therefore with the potential for better position resolution, but which are propagating within all 4 cavities, and modes localized in the cavities or the beam pipes, which can give localized position information, but which provide worse resolution. For a better characterization of these options, a set of test electronics has been built, which can down-convert various frequencies between about 4 and 9 GHz to 70 MHz. The performance of various 20 MHz bands has been estimated. The best resolution of 20 m was found for some propagating modes. Based on this study one band at ca. 5 GHz was chosen for high resolution position monitoring and a band at ca. 9 GHz for localized monitoring.

  5. Concepts for the JLab Ampere-Class CW Cryomodule

    CERN Document Server

    Rimmer, Robert; Henry, James; Hicks, William R; Preble, Joseph P; Stirbet, Mircea; Wang, Haipeng; Wilson, Katherine; Wu, Genfa

    2005-01-01

    We describe the concepts and developments underway at JLab as part of the program to develop a new CW cryomodule capable of transporting ampere-level beam currents in a compact FEL. Requirements include real-estate gradient of at least 10 MV/m and very strong HOM damping to push BBU thresholds up by two or more orders of magnitude compared to existing designs. Cavity shape, HOM damping, power couplers, tuners etc. are being designed and optimized for this application. Cavity considerations include a large iris for beam halo, low-RF losses, HOM frequencies and Q's, low peak surface fields, field flatness and microphonics. Module considerations include high packing factor, low static heat leak, image current heating of beam-line components, cost and maintainability. This module is being developed for the next generation ERL based high power FELs but may be useful for other applications such as electron cooling, electron-ion colliders, industrial processing etc.

  6. Multi-planar amorphous silicon photonics with compact interplanar couplers, cross talk mitigation, and low crossing loss

    Directory of Open Access Journals (Sweden)

    Jeff Chiles

    2017-11-01

    Full Text Available We propose and experimentally demonstrate a photonic routing architecture that can efficiently utilize the space of multi-plane (3D photonic integration. A wafer with three planes of amorphous silicon waveguides was fabricated and characterized, demonstrating < 3 × 1 0 − 4 dB loss per out-of-plane waveguide crossing, 0.05 ± 0.02 dB per interplane coupler, and microring resonators on three planes with a quality factors up to 8.2 × 1 0 4 . We also explore a phase velocity mapping strategy to mitigate the cross talk between co-propagating waveguides on different planes. These results expand the utility of 3D photonic integration for applications such as optical interconnects, neuromorphic computing and optical phased arrays.

  7. OBLIMAP 2.0: a fast climate model–ice sheet model coupler including online embeddable mapping routines

    Directory of Open Access Journals (Sweden)

    T. J. Reerink

    2016-11-01

    Full Text Available This paper accompanies the second OBLIMAP open-source release. The package is developed to map climate fields between a general circulation model (GCM and an ice sheet model (ISM in both directions by using optimal aligned oblique projections, which minimize distortions. The curvature of the surfaces of the GCM and ISM grid differ, both grids may be irregularly spaced and the ratio of the grids is allowed to differ largely. OBLIMAP's stand-alone version is able to map data sets that differ in various aspects on the same ISM grid. Each grid may either coincide with the surface of a sphere, an ellipsoid or a flat plane, while the grid types might differ. Re-projection of, for example, ISM data sets is also facilitated. This is demonstrated by relevant applications concerning the major ice caps. As the stand-alone version also applies to the reverse mapping direction, it can be used as an offline coupler. Furthermore, OBLIMAP 2.0 is an embeddable GCM–ISM coupler, suited for high-frequency online coupled experiments. A new fast scan method is presented for structured grids as an alternative for the former time-consuming grid search strategy, realising a performance gain of several orders of magnitude and enabling the mapping of high-resolution data sets with a much larger number of grid nodes. Further, a highly flexible masked mapping option is added. The limitation of the fast scan method with respect to unstructured and adaptive grids is discussed together with a possible future parallel Message Passing Interface (MPI implementation.

  8. Design

    DEFF Research Database (Denmark)

    Volf, Mette

    This publication is unique in its demystification and operationalization of the complex and elusive nature of the design process. The publication portrays the designer’s daily work and the creative process, which the designer is a part of. Apart from displaying the designer’s work methods...... and design parameters, the publication shows examples from renowned Danish design firms. Through these examples the reader gets an insight into the designer’s reality....

  9. Design and Realization Aspects of 1-THz Cascade Backward Wave Amplifier Based on Double Corrugated Waveguide

    DEFF Research Database (Denmark)

    Paoloni, Claudio; Di Carlo, Aldo; Bouamrane, Fayçal

    2013-01-01

    The design and fabrication challenges in the first ever attempt to realize a 1-THz vacuum tube amplifier are described. Implementation of innovative solutions including a slow-wave structure in the form of a double corrugated waveguide, lateral tapered input and output couplers, deep X-ray LIGA f...

  10. Potencial osteoindutor da matriz óssea homóloga desmineralizada de coelho Osteoinductivity of demineralized homologous bone graft in rabbits

    Directory of Open Access Journals (Sweden)

    Ricardo Junqueira Del Carlo

    2003-06-01

    Full Text Available O trabalho objetivou avaliar o potencial osteoindutor da matriz óssea homóloga (MOD desmineralizada em ácido clorídrico. Em doze coelhos adultos, foi realizada uma incisão sagital mediana na pele abdominal, de aproximadamente 5 cm, e a divulsão do tecido subcutâneo, permitindo que três fragmentos de MOD, com 1 cm de comprimento, fossem implantados em "bolsas" confeccionadas cirurgicamente no músculo reto abdominal. A MOD foi preparada a partir de rádios de coelhos sacrificados por superdosagem anestésica e estocada em etanol 70%, em temperatura ambiente, por, no mínimo, 15 dias, até o momento do uso. Para permitir análise prévia às enxertias, fragmentos de MOD preservados em etanol 70% e fixados em formol a 10% tamponado foram submetidos à rotina histológica. Quatro coelhos foram sacrificados a cada duas, quatro e seis semanas de pós-operatório. A rotina histológica foi realizada, também, em dois dos enxertos implantados em cada animal, em cortes longitudinais e transversais, corados por H&E e no fragmento restante a deposição de osso novo foi evidenciada pela fluorescência da tetraciclina administrada aos animais. Os resultados da pesquisa permitiram concluir que o ácido clorídrico 0,6 N promoveu desmineralização eficaz e manteve o potencial indutor da matriz óssea; a imersão da matriz óssea desmineralizada em etanol 70% propiciou a esterilização dos enxertos homólogos e não inibiu o potencial osteoindutor; e também que, a MOD, devido a fatores indutores inerentes que atuam sobre as células dos tecidos adjacentes, promoveu quimiotaxia, mitose e diferenciação celular.In order to evaluate osteoinduction of the homologous demineralized bone matrix (DBM, 1 cm radial fragments were demineralized in HCL 0.6 N solution for 24 hours, preserved in 70% ethanol solution and implanted in the abdominal musculature of 12 adult rabbits. The animals were sacrificed at 2, 4 and 6 post-operative weeks. After euthanasia

  11. Efecto protector de oncósferas homólogas en la infección por Hymenolepis nana var. nana

    Directory of Open Access Journals (Sweden)

    Oriana Vásquez

    2013-03-01

    Full Text Available El efecto protector de oncósferas homólogas fue evaluado en Mus musculus infectados por Hymenolepis nana var. nana. El estudio se realizó en 20 ejemplares hembras de Mus musculus de dos meses de edad y libres de infección por helmintos, los cuáles fueron seleccionados al azar en dos grupos (experimental y control de 10 ratones cada uno. Cada animal del grupo experimental recibió una dosis única del inmunógeno vía subcutánea, constituido por la mezcla de 0,05 mL de PBS con 15—24 oncósferas y 0,05 mL de Adyuvante Completo de Freund’s para inducir la respuesta inmune. El grupo control recibió por igual vía la misma dosis, pero sin oncósferas. La evaluación del efecto protector de las oncósferas se realizó después de 25 días de la inmunización, para lo cuál 200 huevos viables de H. nana var. nana fueron administrados por vía oral a cada uno de los 20 ratones, los que fueron mantenidos durante 15 días más antes de ser sacrificados para obtener los parásitos intestinales y comprobar la eficiencia de la inmunización. Las formas adultas de Hymenolepis nana var. nana fueron encontrados en dos ratones del grupo experimental y en 5 ratones del grupo control; siendo la eficiencia de la inmunización del 60%, observandose diferencia significativa entre el grupo control y el grupo experimental.

  12. Âge et stress oxydant: Vers un déséquilibre irréversible de l’homéostasie endothéliale

    Science.gov (United States)

    Thorin-Trescases, Nathalie; Voghel, Guillaume; Farhat, Nada; Drouin, Annick; Gendron, Marie-Ève; Thorin, Éric

    2013-01-01

    Différents mécanismes cellulaires de réparation, de défense et de maintien de l’homéostasie sont continuellement activés au cours de la vie. Ils permettent d’établir un équilibre temporaire face aux agressions successives endogènes et exogènes. Le principe d’hormesis*, selon lequel l’exposition à un faible stress induit une meilleure résistance à un stress ultérieur que son absence, permet d’amplifier ces mécanismes d’adaptation cellulaire. Le vieillissement, la sénescence et finalement la mort cellulaire, résultent de l’épuisement des ressources qui maintiennent l’équilibre et réparent les dommages moléculaires. L’endothélium vasculaire est dynamique et très sensible au stress oxydant. Avec l’âge, le changement graduel de l’environnement redox vers un état pro-oxydant contribue à une redistribution progressive des facteurs endothéliaux menant à la dysfonction endothéliale. Nous suggérons qu’une exposition modérée au stress oxydant durant la phase de maturation de l’endothélium détermine la longévité vasculaire, selon le principe bénéfique d’hormesis. PMID:20929680

  13. Injector Cavities Fabrication, Vertical Test Performance and Primary Cryomodule Design

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haipeng [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cheng, Guangfeng [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Clemens, William [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Davis, G [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Macha, Kurt [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Overton, Roland [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Spell, D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    After the electromagnetic design and the mechanical design of a β=0.6, 2-cell elliptical SRF cavity, the cavity has been fabricated. Then both 2-cell and 7-cell cavities have been bench tuned to the target values of frequency, coupling external Q and field flatness. After buffer chemistry polishing (BCP) and high pressure rinses (HPR), Vertical 2K cavity test results have been satisfied the specifications and ready for the string assembly. We will report the cavity performance including Lorenz Force Detuning (LFD) and Higher Order Modes (HOM) damping data. Its integration with cavity tuners to the cryomodule design will be reported.

  14. Homeopathy for Depression - DEP-HOM: study protocol for a randomized, partially double-blind, placebo controlled, four armed study

    Directory of Open Access Journals (Sweden)

    Willich Stefan N

    2011-02-01

    Full Text Available Abstract Background Homeopathy is often sought by patients with depression. In classical homeopathy, the treatment consists of two main elements: the case history and the prescription of an individually selected homeopathic remedy. Previous data suggest that individualized homeopathic Q-potencies were not inferior to the antidepressant fluoxetine in a sample of patients with moderate to severe depression. However, the question remains whether individualized homeopathic Q-potencies and/or the type of the homeopathic case history have a specific therapeutical effect in acute depression as this has not yet been investigated. The study aims to assess the two components of individualized homeopathic treatment for acute depression, i.e., to investigate the specific effect of individualized Q-potencies versus placebo and to investigate the effect of different approaches to the homeopathic case history. Methods/Design A randomized, partially double-blind, placebo-controlled, four-armed trial using a 2 × 2 factorial design with a six-week study duration per patient will be performed. 228 patients diagnosed with major depression (moderate episode by a psychiatrist will be included. The primary endpoint is the total score on the 17-item Hamilton Depression Rating Scale after six weeks. Secondary end points are: Hamilton Depression Rating Scale total score after two and four weeks; response and remission rates, Beck Depression inventory total score, quality of life and safety at two, four and six weeks. Statistical analyses will be by intention-to-treat. The main endpoint will be analysed by a two-factorial analysis of covariance. Within this model generalized estimation equations will be used to estimate differences between verum and placebo, and between both types of case history. Discussion For the first time this study evaluates both the specific effect of homeopathic medicines and of a homeopathic case taking in patients with depression. It is an

  15. Third harmonic cavity design and RF measurements for the Frascati DAΦNE collider

    Directory of Open Access Journals (Sweden)

    David Alesini

    2004-09-01

    Full Text Available Third harmonic passive RF cavities have been proposed for installation in both rings of the DAΦNE factory collider to improve the Touschek lifetime and to increase the Landau damping. This paper illustrates the design of the harmonic cavities. The main requirements were to obtain a relatively low R/Q factor and a quality factor Q as high as possible to satisfy beam dynamics requirements and to damp all the higher order mode (HOM to a harmless level in order to avoid multibunch instabilities. A spherical shape of the cavity central body has been chosen as an optimum compromise between a high Q resonator and a low R/Q factor. HOM suppression has been provided by a ferrite ring damper designed for the superconducting cavities of the high energy ring of the KEK-B factory. The design and electromagnetic properties of the resonant modes have been studied with MAFIA and HFSS codes. Cavities have been made of aluminum and the RF measurements have been performed to characterize them. The measurements are in a good agreement with numerical simulations results, demonstrating a satisfactory HOM damping.

  16. On the photonic implementation of universal quantum gates, bell states preparation circuit and quantum LDPC encoders and decoders based on directional couplers and HNLF.

    Science.gov (United States)

    Djordjevic, Ivan B

    2010-04-12

    The Bell states preparation circuit is a basic circuit required in quantum teleportation. We describe how to implement it in all-fiber technology. The basic building blocks for its implementation are directional couplers and highly nonlinear optical fiber (HNLF). Because the quantum information processing is based on delicate superposition states, it is sensitive to quantum errors. In order to enable fault-tolerant quantum computing the use of quantum error correction is unavoidable. We show how to implement in all-fiber technology encoders and decoders for sparse-graph quantum codes, and provide an illustrative example to demonstrate this implementation. We also show that arbitrary set of universal quantum gates can be implemented based on directional couplers and HNLFs.

  17. Occupational Therapy in HomEcare Re-ablement Services (OTHERS): results of a feasibility randomised controlled trial.

    Science.gov (United States)

    Whitehead, Phillip J; Walker, Marion F; Parry, Ruth H; Latif, Zaid; McGeorge, Ian D; Drummond, Avril E R

    2016-08-16

    warranted; however, the design will require careful consideration because of ongoing national changes in service configurations. ISRCTN21710246; Results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  18. Homeopathy for depression: a randomized, partially double-blind, placebo-controlled, four-armed study (DEP-HOM.

    Directory of Open Access Journals (Sweden)

    Ubiratan C Adler

    Full Text Available BACKGROUND: The specific clinical benefit of the homeopathic consultation and of homeopathic remedies in patients with depression has not yet been investigated. AIMS: To investigate the 1 specific effect of individualized homeopathic Q-potencies compared to placebo and 2 the effect of an extensive homeopathic case taking (case history I compared to a shorter, rather conventional one (case history II in the treatment of acute major depression (moderate episode after six weeks. METHODS: A randomized, partially double-blind, placebo-controlled, four-armed trial using a 2×2 factorial design with a six-week study duration per patient was performed. RESULTS: A total of 44 from 228 planned patients were randomized (2∶1∶2∶1 randomization: 16 homeopathic Q-potencies/case history I, 7 placebo/case history I, 14 homeopathic Q-potencies/case history II, 7 placebo/case history II. Because of recruitment problems, the study was terminated prior to full recruitment, and was underpowered for the preplanned confirmatory hypothesis testing. Exploratory data analyses showed heterogeneous and inconclusive results with large variance in the sample. The mean difference for the Hamilton-D after 6 weeks was 2.0 (95%CI -1.2;5.2 for Q-potencies vs. placebo and -3.1 (-5.9;-0.2 for case history I vs. case history II. Overall, no consistent or clinically relevant results across all outcomes between homeopathic Q-potencies versus placebo and homeopathic versus conventional case taking were observed. The frequency of adverse events was comparable for all groups. CONCLUSIONS: Although our results are inconclusive, given that recruitment into this trial was very difficult and we had to terminate early, we cannot recommend undertaking a further trial addressing this question in a similar setting. Prof. Dr. Claudia Witt had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. TRIAL

  19. Papel e imagen social de las mujeres libres en los poemas homéricos desde la perspectiva de su alteridad/Social role and picture of free women in Homeric poems from the view of their alterity

    National Research Council Canada - National Science Library

    Bárbara Álvarez Rodríguez

    2017-01-01

    ... de esa definición paradigmática de la identidad dominante se construye, por vía de la negación, la alteridad. Entre los muchos grupos de Otros con los que se relacionan los protagonistas de los poemas se encuentra el grupo de las mujeres. El objetivo de este artículo será analizar tanto el papel y la representación que se hace de ellas, como estudiar el tipo de relación que se da con entre la identidad masculina y la alteridad femenina. Palabras clave: poemas homéricos, mujeres, alteridad, identidad dominante, asimetrí...

  20. Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Pettiway, Keon

    2017-01-01

    by designers, planners, etc. (staging from above) and mobile subjects (staging from below). A research agenda for studying situated practices of mobility and mobilities design is outlined in three directions: foci of studies, methods and approaches, and epistemologies and frames of thinking. Jensen begins......In this chapter, Ole B. Jensen takes a situational approach to mobilities to examine how ordinary life activities are structured by technology and design. Using “staging mobilities” as a theoretical approach, Jensen considers mobilities as overlapping, actions, interactions and decisions...... with a brief description of how movement is studied within social sciences after the “mobilities turn” versus the idea of physical movement in transport geography and engineering. He then explains how “mobilities design” was derived from connections between traffic and architecture. Jensen concludes...

  1. Design

    DEFF Research Database (Denmark)

    Volf, Mette

    Design - proces & metode iBog®  er enestående i sit fokus på afmystificering og operationalisering af designprocessens flygtige og komplekse karakter. Udgivelsen går bag om designerens daglige arbejde og giver et indblik i den kreative skabelsesproces, som designeren er en del af. Udover et bredt...... indblik i designerens arbejdsmetoder og designparametre giver Design - proces & metode en række eksempler fra anerkendte designvirksomheder, der gør det muligt at komme helt tæt på designerens virkelighed....

  2. Design and Analysis of 19 cell PCF for Robust Single Mode Operation usingAvoided-Crossing Modes Approach

    Directory of Open Access Journals (Sweden)

    Riyadh MwadNaife

    2017-03-01

    Full Text Available Double-cladding large mode area rod-type photonic crystal fibers have become a key component for power scaling in high power fiber laser systems to provide an ultra large effective area. By a careful design, the single-mode regime can be obtained insuch large core active fibers. In this paper, the 19-cell photonic crystal fibers with 3 rings in the fiber inner cladding have been investigated with the avoided-crossing approach, in order to find guidelines for the design of single-mode fibers. The air-hole diameter and the wavelength have been changed.In a certain point of air-holes diameter and the wavelength for 19cell PCF, the avoided crossing between HOMs has been occurred. In this point, the confinement loss of HOMs is increased which is more ensured for SM operation

  3. Physics design of a 10 MeV, 6 kW travelling wave electron linac for ...

    Indian Academy of Sciences (India)

    2016-10-11

    Oct 11, 2016 ... Three- dimensional transient simulations of the accelerating structure along with the input and output couplers have been performed using the software CST-MWS to explicitly demonstrate this feature. Keywords. Travelling wave; electromagnetic design; integrated buncher; constant impedance; longitudinal.

  4. Physics design of a 10 MeV, 6 kW travelling wave electron linac for ...

    Indian Academy of Sciences (India)

    We present the physics design of a 10 MeV, 6 kW S-band (2856 MHz) electron linear accelerator (linac), which has been recently built and successfully operated at Raja ... Threedimensional transient simulations of the accelerating structure along with the input and output couplers have beenperformed using the software ...

  5. Conceptual design of a high real-estate gradient cavity for a SRF ERL

    Science.gov (United States)

    Xu, Chen; Ben-Zvi, Ilan; Hao, Yue; Xin, Tianmu; Wang, Haipeng

    2017-10-01

    The term ;real-estate gradient; is used to describe the energy gain provided by an accelerating structure per actual length it takes in the accelerator. given that the length of the tunnel available for the accelerator is constrained, the real-estate gradient is an important measure of the efficiency of a given accelerator structure. When designing an accelerating cavity to be efficient in this sense, the unwanted Higher Order Mode (HOM) fields should be reduced by suitable HOM dampers. This is a particularly important consideration for high current operation. The additional RF components might take longitude space and reduce the total accelerating efficiency. We describe a new high efficiency 5-cell cavity with the dampers included. The total length of the cavity is reduced by 13% as compared to a more conventional design without compromising the cavity fundamental-mode performance. In addition, the HOM impedance is reduced for a higher Beam-Break-Up (BBU) threshold of operating current. In this paper, we consider an example, a possible application at the eRHIC Energy Recovery Linac (ERL).

  6. Design

    Science.gov (United States)

    Buchanan, Richard; Cross, Nigel; Durling, David; Nelson, Harold; Owen, Charles; Valtonen, Anna; Boling, Elizabeth; Gibbons, Andrew; Visscher-Voerman, Irene

    2013-01-01

    Scholars representing the field of design were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Richard Buchanan, Nigel Cross, David Durling, Harold Nelson, Charles Owen, and Anna Valtonen. Scholars…

  7. Numerical investigation of polarization insensitive two-mode division (De)multiplexer based on an asymmetric directional coupler

    Science.gov (United States)

    Truong, Cao Dung; Trinh, M. Tuan; Dang, Hoai Bac; Nguyen, Van Tho

    2017-02-01

    We propose a polarization insensitive two-mode division (de)multiplexer based on a silicon-on-insulator platform operating with a broadband, low insertion and scattering loss, and small crosstalk. By using an asymmetric directional coupler, two-mode (de)multiplexing functions for both polarization TE and TM states can be realized by the numerical simulation. Simulated results using a three dimensional beam propagation method (3D-BPM) incorporated with an effective index method (EIM) show high performance of the device with an operation efficiency above 81.2% (i.e., insertion loss is less than 0.9 dB) in the range of ±5 nm around the central wavelength of 1550 nm. Fabrication tolerances also have proved suitability to current manufacture technologies for the planar waveguides. Besides a low scattering loss of the sidewall roughness and a little influence of dispersion, a small footprint can bring the device to applications of high bitrate and compact on-chip silicon photonic integrated circuits.

  8. Development and performance of a new version of the OASIS coupler, OASIS3-MCT_3.0

    Directory of Open Access Journals (Sweden)

    A. Craig

    2017-09-01

    Full Text Available OASIS is coupling software developed primarily for use in the climate community. It provides the ability to couple different models with low implementation and performance overhead. OASIS3-MCT is the latest version of OASIS. It includes several improvements compared to OASIS3, including elimination of a separate hub coupler process, parallelization of the coupling communication and run-time grid interpolation, and the ability to easily reuse mapping weight files. OASIS3-MCT_3.0 is the latest release and includes the ability to couple between components running sequentially on the same set of tasks as well as to couple within a single component between different grids or decompositions such as physics, dynamics, and I/O. OASIS3-MCT has been tested with different configurations on up to 32 000 processes, with components running on high-resolution grids with up to 1.5 million grid cells, and with over 10 000 2-D coupling fields. Several new features will be available in OASIS3-MCT_4.0, and some of those are also described.

  9. Development and performance of a new version of the OASIS coupler, OASIS3-MCT_3.0

    Science.gov (United States)

    Craig, Anthony; Valcke, Sophie; Coquart, Laure

    2017-09-01

    OASIS is coupling software developed primarily for use in the climate community. It provides the ability to couple different models with low implementation and performance overhead. OASIS3-MCT is the latest version of OASIS. It includes several improvements compared to OASIS3, including elimination of a separate hub coupler process, parallelization of the coupling communication and run-time grid interpolation, and the ability to easily reuse mapping weight files. OASIS3-MCT_3.0 is the latest release and includes the ability to couple between components running sequentially on the same set of tasks as well as to couple within a single component between different grids or decompositions such as physics, dynamics, and I/O. OASIS3-MCT has been tested with different configurations on up to 32 000 processes, with components running on high-resolution grids with up to 1.5 million grid cells, and with over 10 000 2-D coupling fields. Several new features will be available in OASIS3-MCT_4.0, and some of those are also described.

  10. Simultaneous measurement of thermo-optic and stress-optic coefficients of polymer thin films using prism coupler technique.

    Science.gov (United States)

    Hossain, Md Faruque; Chan, Hau Ping; Uddin, Mohammad Afsar

    2010-01-20

    We present a simple method for simultaneous measurement of thermo-optic and stress-optic coefficients of polymer thin films by measuring the film refractive indices as a function of temperature (dn/dT). Usually, such dn/dT value is considered as the thermo-optic coefficient. However, in the thin film systems, the measured dn/dT values result from both the thermo-optic and stress-optic effects. To demonstrate the stress-induced effects, the dn/dT values have been investigated for two different polymers: benzocyclobutene (high film stress) and epoxy 3505 (negligible film stress), using a prism coupler technique. The finite element method has been used so as to predict the stresses in the polymer film and, by combining them with the experimental dn/dT values, the individual thermo-optic and stress-optic coefficients have been determined. We found that the obtained thermo-optic coefficient is significantly different than the measured dn/dT values. The method is generic in nature and can thus be applied to a wide range of polymer waveguide materials.

  11. A Novel Wind Turbine Concept Based on an Electromagnetic Coupler and the Study of Its Fault Ride-through Capability

    Directory of Open Access Journals (Sweden)

    Rui You

    2013-11-01

    Full Text Available This paper presents a novel type of variable speed wind turbine with a new drive train different from the variable speed wind turbine commonly used nowadays. In this concept, a synchronous generator is directly coupled with the grid, therefore, the wind turbine transient overload capability and grid voltage support capability can be significantly improved. An electromagnetic coupling speed regulating device (EMCD is used to connect the gearbox high speed shaft and synchronous generator rotor shaft, transmitting torque to the synchronous generator, while decoupling the gearbox side and the synchronous generator, so the synchronous generator torque oscillations during a grid fault are not transmitted to the gearbox. The EMCD is composed of an electromagnetic coupler and a one quadrant operation converter with reduced capability and low cost. A control strategy for the new wind turbine is proposed and a 2 MW wind turbine model is built to study the wind turbine fault ride-through capability. An integrated simulation environment based on the aeroelastic code HAWC2 and software Matlab/Simulink is used to study its fault ride-through capability and the impact on the structural loads during grid three phase and two phase short circuit faults.

  12. Paleodemografía y biología de los homínidos del Pleistoceno Medio de Europa. El caso de la Sima de los Huesos de Atapuerca

    Directory of Open Access Journals (Sweden)

    Bermúdez de Castro, José María

    1998-12-01

    Full Text Available Not available.Las excavaciones sistemáticas realizadas hasta la campaña de 1997 en el yacimiento de la Sima de los Huesos (SH de la Sierra de Atapuerca (Burgos ha proporcionado un excepcional conjunto de más de 2000 restos fósiles humanos pertenecientes a un número mínimo (NMI de 32 individuos. Las características del yacimiento de SH y el estudio tafonómico del registro sugieren un origen antrópico para la acumulación de los homínidos. Sin embargo, la discusión sobre el modelo que se ajusta a la distribución de mortalidad observada, catastrófico vs. atricional, está siendo muy fructífera para las investigaciones sobre ciertas características biológicas de la especie, Homo heidelbergensis, a la que pertenecen los homínidos de SH.

  13. Substrate Specificity of Lymphoid-specific Tyrosine Phosphatase (Lyp) and Identification of Src Kinase-associated Protein of 55 kDa Homolog (SKAP-HOM) as a Lyp Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiao; Chen, Ming; Zhang, Sheng; Yu, Zhi-Hong; Sun, Jin-Peng; Wang, Lina; Liu, Sijiu; Imasaki, Tsuyoshi; Takagi, Yuichiro; Zhang, Zhong-Yin (Indiana-Med)

    2012-02-08

    A missense single-nucleotide polymorphism in the gene encoding the lymphoid-specific tyrosine phosphatase (Lyp) has been identified as a causal factor in a wide spectrum of autoimmune diseases. Interestingly, the autoimmune-predisposing variant of Lyp appears to represent a gain-of-function mutation, implicating Lyp as an attractive target for the development of effective strategies for the treatment of many autoimmune disorders. Unfortunately, the precise biological functions of Lyp in signaling cascades and cellular physiology are poorly understood. Identification and characterization of Lyp substrates will help define the chain of molecular events coupling Lyp dysfunction to diseases. In the current study, we identified consensus sequence motifs for Lyp substrate recognition using an 'inverse alanine scanning' combinatorial library approach. The intrinsic sequence specificity data led to the discovery and characterization of SKAP-HOM, a cytosolic adaptor protein required for proper activation of the immune system, as a bona fide Lyp substrate. To determine the molecular basis for Lyp substrate recognition, we solved crystal structures of Lyp in complex with the consensus peptide as well as the phosphopeptide derived from SKAP-HOM. Together with the biochemical data, the structures define the molecular determinants for Lyp substrate specificity and provide a solid foundation upon which novel therapeutics targeting Lyp can be developed for multiple autoimmune diseases.

  14. Representability of Hom implies flatness

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    School of Mathematics, Tata Institute of Fundamental Research, Homi Bhabha Road,. Mumbai 400 005, India. E-mail: nitsure@math.tifr.res.in. MS received 8 August 2003. Abstract. ... 'scalar-multiplication' morphism µ : A1. S ×S V → V over S, such that the module axioms. (in diagrammatic terms) are satisfied. A linear ...

  15. Using the Real-Ear-to-Coupler Difference within the American Academy of Audiology Pediatric Amplification Guideline: Protocols for Applying and Predicting Earmold RECDs.

    Science.gov (United States)

    Moodie, Sheila; Pietrobon, Jonathan; Rall, Eileen; Lindley, George; Eiten, Leisha; Gordey, Dave; Davidson, Lisa; Moodie, K Shane; Bagatto, Marlene; Haluschak, Meredith Magathan; Folkeard, Paula; Scollie, Susan

    2016-03-01

    Real-ear-to-coupler difference (RECD) measurements are used for the purposes of estimating degree and configuration of hearing loss (in dB SPL ear canal) and predicting hearing aid output from coupler-based measures. Accurate measurements of hearing threshold, derivation of hearing aid fitting targets, and predictions of hearing aid output in the ear canal assume consistent matching of RECD coupling procedure (i.e., foam tip or earmold) with that used during assessment and in verification of the hearing aid fitting. When there is a mismatch between these coupling procedures, errors are introduced. The goal of this study was to quantify the systematic difference in measured RECD values obtained when using a foam tip versus an earmold with various tube lengths. Assuming that systematic errors exist, the second goal was to investigate the use of a foam tip to earmold correction for the purposes of improving fitting accuracy when mismatched RECD coupling conditions occur (e.g., foam tip at assessment, earmold at verification). Eighteen adults and 17 children (age range: 3-127 mo) participated in this study. Data were obtained using simulated ears of various volumes and earmold tubing lengths and from patients using their own earmolds. Derived RECD values based on simulated ear measurements were compared with RECD values obtained for adult and pediatric ears for foam tip and earmold coupling. Results indicate that differences between foam tip and earmold RECDs are consistent across test ears for adults and children which support the development of a correction between foam tip and earmold couplings for RECDs that can be applied across individuals. The foam tip to earmold correction values developed in this study can be used to provide improved estimations of earmold RECDs. This may support better accuracy in acoustic transforms related to transforming thresholds and/or hearing aid coupler responses to ear canal sound pressure level for the purposes of fitting behind

  16. Design of optical metamaterial waveguide structures (Conference Presentation)

    Science.gov (United States)

    Ortega-Moñux, Alejandro; Halir, Robert; Sánchez-Postigo, Alejandro; Soler-Penadés, Jordi; Ctyroký, Jirí; Luque-González, José Manuel; Sarmiento-Merenguel, José Darío.; Wangüemert-Pérez, Juan Gonzalo; Schmid, Jens H.; Xu, Dan-Xia; Janz, Sigfried; Lapointe, Jean; Molina-Fernández, Iñigo; Nedeljkovic, Milos; Mashanovich, Goran Z.; Cheben, Pavel

    2017-05-01

    Subwavelength gratings (SWGs) are periodic structures with a pitch (Λ) smaller than the wavelength of the propagating wave (λ), so that diffraction effects are suppressed. These structures thus behave as artificial metamaterials where the refractive index and the dispersion profile can be controlled with a proper design of the geometry of the structure. SWG waveguides have found extensive applications in the field of integrated optics, such as efficient fiber-chip couplers, broadband multimode interference (MMI) couplers, polarization beam splitters or evanescent field sensors, among others. From the point of view of nano-fabrication, the subwavelength condition (Λ electromagnetic simulation of Floquet modes, the relevance of substrate leakage losses and the effects of the random jitter, inherent to any fabrication process, on the performance of SWG structures. Finally, we will show the possibilities of the design of SWG structures with two different state-of-the-art applications: i) ultra-broadband MMI beam splitters with an operation bandwidth greater than 300nm for telecom wavelengths and ii) a set of suspended waveguides with SWG lateral cladding for mid-infrared applications, including low loss waveguides, MMI couplers and Mach-Zehnder interferometers.

  17. Design and Development of Monolithic Microwave Integrated Amplifiers and Coupling Circuits for Telecommunication Systems Applications

    Directory of Open Access Journals (Sweden)

    R. Makri

    2002-01-01

    quadrature coupler and a Wilkinson one in order to reduce size. Finally, a two stages low noise amplifier was designed with the use of H40 GaAs process in order the differences between the relevant designs to be explored. The key specifications for this MMIC LNA include operation at 10 GHz with a total gain of 17 dB while the noise figure is less than 1.5 dB.

  18. Design and Fabrication of SOI-based photonic crystal components

    DEFF Research Database (Denmark)

    Borel, Peter Ingo; Frandsen, Lars Hagedorn; Harpøth, Anders

    2004-01-01

    We present examples of ultra-compact photonic crystal components realized in silicon-on-insulator material. We have fabricated several different types of photonic crystal waveguide components displaying high transmission features. This includes 60° and 120° bends, different types of couplers......, and splitters. Recently, we have designed and fabricated components with more than 200 nm bandwidths. Design strategies to enhance the performance include systematic variation of design parameters using finite-difference time-domain simulations and inverse design methods such as topology optimization....

  19. Design and Measurements of an X-Band Accelerating Cavity for SPARC

    CERN Document Server

    Alesini, David; Falone, Antonio; Ferrario, Massimo; Migliorati, Mauro; Mostacci, Andrea; Palpini, Federica; Palumbo, Luigi; Spataro, Bruno

    2005-01-01

    The paper presents the design of an X-band accelerating section for linearizing the longitudinal phase space in the Frascati Linac Coherent Light Source (SPARC). The structure, operating on the pi standing wave mode, is a 9 cells structure feeded by a central waveguide coupler and has been designed to obtain a 5 MV accelerating voltage. The 2D profile has been obtained using the e.m. codes SUPERFISH and OSCARD2D while the coupler has been designed using HFSS. Bead-pull measurement made on a copper prototype are illustrated and compared with the numerical results. Mechanical details of the realized prototype and RF properties of the structure as a function of the assembly characteristics are also discussed.

  20. Design and characterization of integrated components for SiN photonic quantum circuits.

    Science.gov (United States)

    Poot, Menno; Schuck, Carsten; Ma, Xiao-Song; Guo, Xiang; Tang, Hong X

    2016-04-04

    The design, fabrication, and detailed calibration of essential building blocks towards fully integrated linear-optics quantum computation are discussed. Photonic devices are made from silicon nitride rib waveguides, where measurements on ring resonators show small propagation losses. Directional couplers are designed to be insensitive to fabrication variations. Their offset and coupling lengths are measured, as well as the phase difference between the transmitted and reflected light. With careful calibrations, the insertion loss of the directional couplers is found to be small. Finally, an integrated controlled-NOT circuit is characterized by measuring the transmission through different combinations of inputs and outputs. The gate fidelity for the CNOT operation with this circuit is estimated to be 99.81% after post selection. This high fidelity is due to our robust design, good fabrication reproducibility, and extensive characterizations.

  1. Fiber optofluidic biosensor for the label-free detection of DNA hybridization and methylation based on an in-line tunable mode coupler.

    Science.gov (United States)

    Gao, Ran; Lu, Dan-Feng; Cheng, Jin; Jiang, Yi; Jiang, Lan; Xu, Jian-Dong; Qi, Zhi-Mei

    2016-12-15

    An optical fiber optofluidic biosensor for the detection of DNA hybridization and methylation has been proposed and experimentally demonstrated. An in-line fiber Michelson interferometer was formed in the photonic crystal fiber. A micrhole in the collapsed region, which combined the tunable mode coupler and optofluidic channel, was fabricated by using femtosecond laser micromachining. The mode field diameter of the guided light is changed with the refractive index in the optofluidic channel, which results in the tunable coupling ratio. Label-free detections of the DNA hybridization and methylation have been experimentally demonstrated. The probe single stranded DNA (ssDNA) was bound with the surface of the optofluidic channel through the Poly-l-lysine layer, and the hybridization between a short 22-mer probe ssDNA and a complementary target ssDNA was carried out and detected by interrogating the fringe visibility of the reflection spectrum. Then, the DNA methylation was also detected through the binding between the methylated DNA and the 5-methylcytosine (5-mC) monoclonal antibody. The experiments results demonstrate that the limit of detection of 5nM is achieved, establishing the tunable mode coupler as a sensitive and versatile biosensor. The sensitive optical fiber optofluidic biosensor possesses high specificity and low temperature cross-sensitivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Case of late-onset, relapsing surgical site infection related to a venous coupler placed during free flap reconstruction for major head and neck cancer.

    Science.gov (United States)

    Ren, Yin; Deschler, Daniel G; Sajed, Dipti; Durand, Marlene L

    2018-01-12

    Venous coupling devices are widely used during reconstructive surgery involving microvascular anastomosis but have not served as foreign bodies in head and neck surgical site infections. We conducted a case report. A patient underwent resection and free flap reconstruction for recurrent tongue squamous cell carcinoma. She developed a neck abscess due to Streptococcus intermedius 7 weeks postoperatively, days after starting chemoradiotherapy. The surgical site infection healed with drainage and antibiotics. Two surgical site infection relapses due to S. intermedius occurred 3 and 8 weeks after completing radiation, the second relapse after a prolonged course of i.v. antibiotics. Surgical exploration revealed a venous coupler within granulation tissue. The device was removed and no further surgical site infection relapses occurred. To the best of our knowledge, this is the first report of a delayed-onset head and neck surgical site infection in which a venous coupler served as a foreign body. An infected foreign body should be suspected in relapsing surgical site infections due to a single organism. © 2018 Wiley Periodicals, Inc.

  3. Diversidad dental en los homínidos de la cueva superior de Zhoukoudian (norte de China y sus implicancias para la historia poblacional del este de Asia y el poblamiento temprano de las Américas

    Directory of Open Access Journals (Sweden)

    Delgado Burbano, Miguel Eduardo

    2007-01-01

    Full Text Available Se comparó la incidencia de 16 rasgos dentales no-métricos en los homínidos de la Cueva Superior de Zhoukoudian (UC (c. 34-29 Ka-Norte de China con otras poblaciones del noreste y sudeste de Asia. Contrario a lo sugerido previamente, la morfología dental de UC posee un sorprendente parecido con el patrón sundadonte típico del sudeste de Asia. Gráficos de dispersión usando un análisis de componentes principales (ACP ubican a UC cerca de otras poblaciones relacionadas con el sudeste de Asia indicando una afinidad sundadonte. Un análisis de distancias biológicas usando la distancia euclidiana al cuadrado (DE seguida de una prueba de escalamiento multidimensional (MDS produjo resultados muy similares. Una comparación entre UC y varias muestras sinodontes de las Américas no soporta el concepto de una afinidad cercana, producto de un supuesto origen común. Previos estudios sobre una posible relación entre el Asia Sudoriental y Sudamérica se ven corroborados en este estudio, debido a la notable afinidad existente entre diferentes muestras dentales de Sudamérica, Asia Sudoriental y los homínidos de UC. La afinidad sundadonte de la muestra de Zhoukoudian detectada en este análisis sugiere que las siguientes hipótesis deben reevaluarse: 1 UC se derivan de una antigua población sinodonte en el noreste de Asia. 2 Hace poco más de 30 Ka sundadonte evolucionó hacia sinodonte en el norte de China, Mongolia y/o el sur de Siberia. 3 Existe una continuidad sinodonte desde Zhoukoudian (34. Ka hasta Dawenkou (6. Ka en el norte de China. 4 Dado que UC posee características dentales sinodontes, debe presentar una estrecha relación con poblaciones recientes del noreste de Asia y todos los nativos americanos pasados y presentes. Finalmente estos hallazgos contradicen el modelo de evolución local o de continuidad morfológico-regional para la historia poblacional del este de Asia y además sugieren que al menos una parte de los nativos

  4. Hemodilución normovolémica intencional alternativa práctica para la transfusión homóloga de sangre en cirugía general y especializada

    Directory of Open Access Journals (Sweden)

    Lázaro Manuel Fernández Suárez

    2000-08-01

    Full Text Available La hemodilución normovolémica intencional es una técnica útil que reduce los requerimientos transfusionales entre el 15 y el 40 %. Representa un ahorro de sangre homóloga, crea una reserva de sangre autógena, reduce el número de hematíes perdidos en la hemorragia quirúrgica, además mejora el flujo sanguíneo y disminuye la viscosidad de la sangre, para aumentar la oxigenación hística y reducir la posibilidad de tromboembolismo pulmonar entre otros beneficios. Se realizó un estudio prospectivo con 50 pacientes supuestamente sanos con la categoría I-II de la A.S.A. (American Society of Anesthesia sobre el uso de la hemodilución normovolémica. Se efectuó la extracción según nomograma para llevar el hematócrito a 0,25 preoperatoriamente, corroborado por la técnica de microhematócrito y controlado en el transoperatorio; no se apreció movimiento anormal en los valores del coagulograma. Se apreció un incuestionable ahorro de sangre homóloga con el consiguiente beneficio para el pacienteIntentional normovolemic hemodilution is a useful technique reducing the transfusion requirements by 15 to 40%. It represents a saving of homologous blood, creates a reserve of antigen blood, reduces the number of hematids lost in a surgical haemorrhage, improves blood flow and lower blood viscosity to increase hystic oxigenation and decrease the possibilities of pulmonar thromboembolism among other benefits. A retrospective study of 50 supposedly healthy patients with catetory I-II of ASA (American Society of Anesthesia was made on the use of normovolemic dilution. According to a nomogram, blood extraction was made to take hematocrit to 0.25 before surgery, a value that was confirmed with microhematocrit technique and intraoperative controlled. No abnormal fluctuation of coagulation test values were observed. There was an unquestionable saving of homologous blood with the corresponding benefit for the patient

  5. Contribution à l'étude de l'écologie et de la biologie des homoptères ravageurs des arbres fruitiers et autres plantes I.- Comparaison de l'évolution des populations d'Aleurodicus dispersus Russell (Hom.: Aleyrodidae) sur agrumes et avocatier en République du Congo

    OpenAIRE

    Kiyindou, A.

    2002-01-01

    Contribution to the Knowledge of the Ecology and Biology of Homopterous Pests of Fruit Trees and other Plants I.- Comparaison of Evolution of Population of Aleurodicus dispersus Russell (Hom.: Aleyrodidae) on Citrus and Avocado Trees in the Republic of the Congo. Aleurodicus dispersus Russell, a whitefly of neotropical origin, was introduced into Congo in the early '90. Since 1995, A. dispersus has developped the important populations on Citrus and avocado trees. The study of the population d...

  6. Design of a high power TM01 mode launcher optimized for manufacturing by milling

    Energy Technology Data Exchange (ETDEWEB)

    Dal Forno, Massimo [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-12-15

    Recent research on high-gradient rf acceleration found that hard metals, such as hard copper and hard copper-silver, have lower breakdown rate than soft metals. Traditional high-gradient accelerating structures are manufactured with parts joined by high-temperature brazing. The high temperature used in brazing makes the metal soft; therefore, this process cannot be used to manufacture structures out of hard metal alloys. In order to build the structure with hard metals, the components must be designed for joining without high-temperature brazing. One method is to build the accelerating structures out of two halves, and join them by using a low-temperature technique, at the symmetry plane along the beam axis. The structure has input and output rf power couplers. We use a TM01 mode launcher as a rf power coupler, which was introduced during the Next Linear Collider (NLC) work. The part of the mode launcher will be built in each half of the structure. This paper presents a novel geometry of a mode launcher, optimized for manufacturing by milling. The coupler was designed for the CERN CLIC working frequency f = 11.9942 GHz; the same geometry can be scaled to any other frequency.

  7. Reparação do ligamento cruzado cranial de cães por tendão homólogo conservado em glicerina e associado a fio de náilon

    Directory of Open Access Journals (Sweden)

    Oliveira Simone Tostes de

    2003-01-01

    Full Text Available A ruptura do ligamento cruzado cranial (LCC é uma das patologias de maior prevalência no joelho de cães e sua correção é um problema atual. Após a ruptura experimental do LCC, em cães, implantou-se o tendão do músculo extensor longo dos dedos, homólogo, conservado em glicerina a 98%, associado ao fio de mononáilon, utilizando-se técnica intra-articular. Foram utilizados 18 cães com peso médio de 16,5kg, adultos, separados em três grupos (A, B e C e avaliados por 45, 80 e 120 dias de pós-operatório, respectivamente. Foi realizada avaliação clínica, radiográfica, macroscópica e histológica. A técnica demonstrou-se eficiente para o retorno funcional do membro promovendo estabilidade articular, apesar de o implante biológico ter sido reabsorvido na maioria dos animais, e do fio de náilon ter perdido sua tensão inicial.

  8. The first operation of 56 MHz SRF cavity in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Q. [Brookhaven National Lab. (BNL), Upton, NY (United States); Belomestnykh, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ben-Zvi, I. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); DeSanto, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Goldberg, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Harvey, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hayes, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); McIntyre, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Orfin, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Seberg, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Severino, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Smith, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Than, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zaltsman, A. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-03

    A 56 MHz superconducting RF cavity has been designed, fabricated and installed in the Relativistic Heavy Ion Collider (RHIC). The cavity operates at 4.4 K with a “quiet helium source” to isolate the cavity from environmental acoustic noise. The cavity is a beam driven quarter wave resonator. It is detuned and damped during injection and acceleration cycles and is brought to operation only at store energy. For a first test operation, the cavity voltage was stabilized at 300 kV with full beam current. Within both Au + Au and asymmetrical Au + He3 collisions, luminosity improvement was detected from direct measurement, and the hourglass effect was reduced. One higher order mode (HOM) coupler was installed on the cavity. We report in this paper on our measurement of a broadband HOM spectrum excited by the Au beam.

  9. Progress toward NLC / GLC prototype accelerator structures

    CERN Document Server

    Wang, J W; Arkan, T; Baboi, N; Boffo, C; Bowden, G B; Burke, D L; Carter, H; Chan, J; Cornuelle, J; Döbert, Steffen; Dolgashev, Valery A; Finley, D; Gonin, I; Higashi, Y; Higo, T; Jones, R M; Khabiboulline, T; Kume, T; Lewandowski, J; Li, Z; Miller, R H; Mishra, S; Morozumi, Y; Nantista, C; Pearson, C; Romanov, G; Ruth, Ronald D; Solyak, N; Tantawi, S; Toge, N; Ueno, K; Wilson, P B; Xiao, L

    2004-01-01

    The accelerator structure groups for NLC (Next Linear Collider) and GLC (Global Linear Colliders) have successfully collaborated on the research and development of a major series of advanced accelerator structures based on room-temperature technology at X-band frequency. The progress in design, simulation, microwave measurement and high gradient tests are summarized in this paper. The recent effort in design and fabrication of the accelerator structure prototype for the main linac is presented in detail including HOM (High Order Mode) suppression and couplers, fundamental mode couplers, optimized accelerator cavities as well as plans for future structures. We emphasize techniques to reduce the field on the surface of the copper structures (in order to achieve high accelerating gradients), limit the dipole wakefields (to relax alignment tolerance and prevent a beam break up instability) and improve shunt impedance (to reduce the RF power required).

  10. The interaction between a beam and a superconducting cavity module: Measurements in CESR and CESR-Phase 3 goals

    Energy Technology Data Exchange (ETDEWEB)

    Belomestnykh, S.; Flynn, G.; Hartung, W.; Kirchgessner, J.; Moffat, D.; Muller, H.; Padamsee, H.; Pisharody, M.; Veshcherevich, V. [Cornell Univ., Ithaca, NY (United States). Lab. of Nuclear Studies

    1996-08-01

    Plans for the next generation of electron-positron colliders (B-factories and B-factory-like machines) call for high beam currents to produce luminosities of the order of 10 (exp 33). To store these high currents in a machine, special attention must be paied to the interaction of the beam with discontinuities in the surrounding vacuum chamber. RF cavities are among the biggest perturbations in accelerator vacuum chambers and are therefore among the biggest sources of beam instabilities. Accelerating structures of new machines are being designed to have smaller impedance to reduce the beam-cavity interaction. Prototypes for the cavity, input coupler, cryostat, and higher-order mode (HOM) loads were subjected and are tested in CESR. A superconducting (SRF) cavity was installed in addition to the four five-cell normal conducting cavities. As a result, the calorimetry and RF power results agree with predictions up to their respective uncertainties. The results of wake potential sampling suggested that the wake fields of the SRF cavity will not limit the performance of CESR in bunch train operation. No beam instabilities or dangerous HOMs were encountered while sweeping the HOM frequencies using the cavity tuner or while exciting multipole HOMs by displacing the beam off axis. (G.K.)

  11. Design and Analysis of an all-fiber MZI Interleaver Based on Fiber Ring Resonator

    Directory of Open Access Journals (Sweden)

    Pu Huilan

    2015-01-01

    Full Text Available An all-fiber Mach-Zehnder interferometer (MZI interleaver using one planar 3×3 fiber coupler, one 2×2 fiber coupler and one 8-shaped fiber ring resonator is developed by the new configuration. Based on its structure, the output spectrum expression is established and described by using the principle of fiber transmission and the matrix transfer function. The results of numerical simulation indicate that when the length difference of interference arms and the coupling coefficients of the couplers are some certain values, it obtains a uniform flat-top passband and similar to rectangular output spectrum. Compared with the traditional MZI interleaver, the isolation in stopband and the rolloff in transition band are strengthen, the 25dB stopband bandwidth and 0.5dB passband bandwidth are simultaneously remarkably improved. Compared with the asymmetrical ring resonator MZI interleaver, the influence of transmission loss on extinction ratio can be effectively reduced. The device has a certain ability to resist the deviation, which reduces the difficulties in fabricating it. The experiment results agree with the theoretical analysis well. The interleaver designed by the proposed approach has favorable performance, which has the potential application value in optical fiber communication system.

  12. RF Design for the Linac Coherent Light Source (LCLS) Injector

    CERN Document Server

    Dowell, D H; Boyce, Richard F; Hodgson, J A; Li, Zenghai; Limborg-Deprey, C; Xiao, Liling; Yu, Nancy

    2004-01-01

    The Linac Coherent Light Source (LCLS) will be the world’s first free electron laser, and the successful operation of this very short-wavelength FEL will require excellent beam quality from its electron source. Therefore a critical component is the RF photocathode injector. This paper describes the design issues of the LCLS RF gun and accelerator structures. The injector consists of a 1.6 cell s-band gun followed by two 3-meter SLAC sections. The gun and the first RF section will have dual RF feeds both to eliminate transverse RF kicks and to reduce the pulsed heating of the coupling ports. In addition, the input coupler cavity of the first accelerator section will be specially shaped to greatly reduce the RF quadrupole fields. The design for the accelerator section is now complete, and the RF design of the gun’s dual coupler and the full cell shape is in progress. These and other aspects of the gun and structure designs will be discussed.

  13. Enxertos homólogos de esclera e dura-máter em olhos de coelhos: análise histopatológica comparativa Homologous scleral and dura mater grafts in rabbit eyes

    Directory of Open Access Journals (Sweden)

    Davi Araf

    2007-12-01

    Full Text Available OBJETIVO: Avaliar a reação tecidual à implantação de enxertos homólogos de esclera e dura-máter. MÉTODOS: Foram realizadas cirurgias experimentais em 41 coelhos albinos da raça Nova Zelândia, sendo que dois coelhos foram selecionados, ao acaso, para serem doadores dos enxertos a serem utilizados no experimento. Trinta coelhos foram divididos em dois grupos: grupo D e grupo E, sendo submetidos à implantação dos tecidos homólogos e nove animais constituíram o grupo controle (grupo DE, submetidos à cirurgia sem enxertia. Os olhos foram enucleados e amostras foram colhidas em duas, seis e 12 semanas após o experimento, constituindo os subgrupos I, II e III. RESULTADOS: Foi realizada análise histopatológica qualitativa, além de estudo semiquantitativo comparativo da vascularização e infiltrado inflamatório na esclera e dura-máter transplantadas. Procedeu-se, também, a histomorfometria das medidas do lado dos enxertos com sistema analisador de imagens. Não houve diferença estatisticamente significante comparando-se a vascularização, infiltrado inflamatório e medidas do lado, entre os subgrupos I de esclera em relação à dura-máter, assim como nos subgrupos II. Não foram comparados os subgrupos III, pois foram observados somente fragmentos dos enxertos de dura-máter. CONCLUSÕES: O enxerto de dura-máter mostrou intensa reabsorção e progressiva substituição por tecido conjuntivo frouxo. O enxerto de esclera mostrou discreta reabsorção na periferia com formação de membrana fibrosa mais evidente, integrando este à esclera do hospedeiro.PURPOSE: To evaluate tissue reaction to implantation of homologous scleral and dura mater grafts. METHODS: Experimental surgeries were performed on 41 albine New Zealand rabbits; two rabbits were selected at random to be graft donors. Thirty rabbits were divided into two groups: group D and group E, receiving grafts of homologous tissues. The remaining nine animals comprised the

  14. Bright white-light emission from Ag/SiO2/CdS-ZnS core/shell/shell plasmon couplers.

    Science.gov (United States)

    Liao, Chen; Tang, Luping; Gao, Xiaoqin; Xu, Ruilin; Zhang, Huichao; Yu, Yongya; Lu, Changgui; Cui, Yiping; Zhang, Jiayu

    2015-12-28

    Well-defined plasmon couplers (PCs) that comprise a Ag core overcoated with a SiO(2) shell with controlled thickness, followed by a monolayer of CdS-ZnS core-shell quantum dots (QDs) were synthesized to modify the emission from trap-rich CdS-ZnS QDs by adjusting the distance between the QDs and Ag nanoparticles (NPs). When the thickness of the SiO(2) shell was 10 nm, because the shell could effectively suppress the non-radiative energy transfer from the semiconductor QDs to the metal NPs and the localized surface plasmon resonance (LSPR) of the Ag NPs spectrally matched the emission peak of the CdS-ZnS QDs to bring about strong plasmon coupling, optimum enhancements of the surface state emission (SSE) (17 times) and band-edge emission (BEE) (4 times) were simultaneously realized and the SSE to BEE intensity ratio was increased to 55%. As a result, a bright white-light source with 1931 Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (0.32, 0.34) was realized by the superposition of the two emissions. The experimental results from Ag/SiO(2)/CdSe-ZnS and the Ag/SiO(2)/CdS:Mn-ZnS core/shell/shell PCs indicated that suppressing the non-radiative decay rate (k(nr)) was the underlying mechanism for plasmon coupling fluorescence enhancement.

  15. Highly efficient and robust operation of Kerr-lens mode-locked Cr:LiSAF lasers using gain-matched output couplers.

    Science.gov (United States)

    Canbaz, Ferda; Beyatli, Ersen; Chen, Li-Jin; Sennaroglu, Alphan; Kärtner, Franz X; Demirbas, Umit

    2014-01-15

    We present efficient and robust Kerr-lens mode locking (KLM) of a diode-pumped Cr:LiSAF laser using a gain-matched output coupler (GMOC). An inexpensive, battery-powered 660 nm single-spatial-mode diode was used as the pump source. GMOC enhances the effective self-amplitude modulation depth by reducing the gain-filtering effect in broadband KLM operation to provide significant improvement in efficiency and robustness. Pulsing can be initiated without careful cavity alignment and is sustained for hours. 13 fs pulses with an average power of 25 mW have been generated using only 120 mW of pump power. The corresponding pulse energy and peak power is 200 pJ and 15 kW for the 126 MHz repetition rate cavity. Optical-to-optical conversion efficiency of the system is 21%, which represents an order of magnitude improvement in reported efficiencies for such diode-pumped ultrashort-pulse KLM Cr:LiSAF lasers. The obtainable pulse width is currently limited by the dispersion bandwidth of the available optics and can be potentially reduced to below 7 fs.

  16. Broadband 2 × 2 lithium niobate electro-optic switch based on a Mach-Zehnder interferometer with counter-tapered directional couplers.

    Science.gov (United States)

    Wang, Hangli; Li, Xuepeng; Zhang, Mengruo; Chen, Kaixin

    2017-10-10

    We demonstrate a broadband 2×2 electro-optic switch based on a Mach-Zehnder interferometer with counter-tapered directional couplers (DCs). The counter-tapered DC is introduced here to replace the conventional one formed with uniform waveguides so that a splitting ratio of 50%∶50% is much easier to be realized over a wide wavelength range and, hence, increase bandwidth of the switch. The proposed switch is fabricated with x-cut lithium niobate by the annealed proton exchange process. A comparison of several experimental devices, fabricated on the same chip with the conventional and different counter-tapered DCs, respectively, confirms the increase of the bandwidth and the improvement of the fabrication tolerance by using the counter-tapered DC. Our fabricated best device, which has a length of ∼22  mm, exhibits an ∼85  nm bandwidth for an extinction ratio (ER) higher than 15 dB and a maximum ER of ∼35  dB at 1563 nm at a driving voltage of 6.0 V. The insertion losses are less than 8.5 dB for all channels. Our proposed optical switch could find applications in wavelength-division-multiplexing optical communication systems.

  17. Design and Manufacturing Criteria for Beam Position Monitor (BPM) of Taiwan Photon Source (TPS)

    Science.gov (United States)

    Hsueh, H. P.; Chang, C. C.; Hsu, S. N.; Huang, I. T.; Chen, Y. B.; Kuan, C. K.; Hsiung, G. Y.; Chen, J. R.

    2010-06-01

    There are quite some considerations when the button feedthrough is designed and manufactured in a new 3rd generation synchrotron light source like the to-be-constructed TPS. It is the responsibility of the button feedthrough designer to design a feedthrough with the lowest probable HOM problem. It is also required for the designer to analyze the consequences for each possible mechanical error during manufacturing and therefore set standards of tolerance. We have been using MAFIA to optimize the design of feedthrough including flange type on bending chamber section and primary BPM on insertion device section. We also have set some criteria for feedthrough manufacturing, inspection, and welding based on hands-on experience on feedthrough electrical properties measuring, sorting, inspection, and laser welding. Here we will present the MAFIA results, electrical measurement results, and laser welding results and analysis. Criteria based on these results will also be presented.

  18. Reparação de defeitos osteocondrais de cães com implante de cultura de condrócitos homólogos e membrana biossintética de celulose: avaliação clínica, ultrassonográfica e macroscópica

    Directory of Open Access Journals (Sweden)

    L.S. Iamaguti

    2012-12-01

    Full Text Available Avaliou-se o implante de condrócitos homólogos em lesões osteocondrais, utilizando a membrana biossintética à base de celulose (MBC como revestimento. Dez cães adultos e clinicamente sadios foram submetidos à artrotomia das articulações fêmoro-tíbio-patelares. Defeitos de quatro milímetros de diâmetro por quatro milímetros de profundidade foram induzidos na tróclea femoral de ambos os membros. A MBC foi aplicada na base e superfície das lesões. Os defeitos do membro direito foram preenchidos com condrócitos homólogos cultivados e formaram o grupo tratado (GT; e os defeitos do membro esquerdo, sem implante celular, formaram o grupo controle (GC. Os animais foram avaliados clínica e ultrassonograficamente aos 30 e 60 dias. A evolução pós-operatória dos cães foi analisada com especial interesse nos processos de reparação da lesão, por meio de macroscopia. Não houve diferença clínica e ultrassonográfica entre os grupos. Entretanto, à macroscopia, ocorreu maior prevalência de formação de tecido cicatricial esbranquiçado no GT. O tecido neoformado apresentou melhor qualidade associado ao implante homólogo de condrócitos, mas não promoveu reparação por cartilagem hialina.

  19. Design of large mode area, mode selection fiber

    Science.gov (United States)

    Jin, Liang; Xu, Li; Zhang, He; Zou, Yonggang; Ding, Ye; Ma, Xiaohui

    2014-12-01

    The paper study on the effect of index distribution on the mode field and calculated the mode distribution in various index profiles. A single mode gaussian hybrid multicore fiber with 19 hexagonally arranged high index quartz rods is designed and investigated. Theoretical and simulative results are presented and compared to the conventional large mode area double clad fiber, the fundamental mode (FM) area can be reached 694.28 μm2, the confinement loss of FM and high order modes (HOMs) are 0.186 dB/m and 1.48 dB/m respectively with the bending radius of 20 cm at 1.064 μm wavelength, moreover, the index distribution can resistant the mode field distortion, which caused by fiber bending. So the FM delivery can be formed and the beam quality can be improved.

  20. Report on HOM experimental methods and code

    CERN Document Server

    Shinton, I R R; Flisgen, T

    2013-01-01

    Experimental methods and various codes used are reported on with the aim to understand the signals picked up from the higher order modes in the third harmonic cavities within the ACC39 module at FLASH. Both commercial computer codes have been used, and also codes written for the express purpose of understanding the sensitivity of the modal profiles to geometrical errors and other sources of experimental errors.

  1. Ferrite HOM Absorber for the RHIC ERL

    Energy Technology Data Exchange (ETDEWEB)

    Hahn,H.; Choi, E.M.; Hammons, L.

    2008-10-01

    A superconducting Energy Recovery Linac is under construction at Brookhaven National Laboratory to serve as test bed for RHIC upgrades. The damping of higher-order modes in the superconducting five-cell cavity for the Energy-Recovery linac at RHIC is performed exclusively by two ferrite absorbers. The ferrite properties have been measured in ferrite-loaded pill box cavities resulting in the permeability values given by a first-order Debye model for the tiled absorber structure and an equivalent permeability value for computer simulations with solid ring dampers. Measured and simulated results for the higher-order modes in the prototype copper cavity are discussed. First room-temperature measurements of the finished niobium cavity are presented which confirm the effective damping of higher-order modes in the ERL. by the ferrite absorbers.

  2. Väike vapper maja / Tina Hom

    Index Scriptorium Estoniae

    Hom, Tina

    2011-01-01

    Väikesest, üle saja aasta vanusest, ümberehitustega mugavast majakesest Provence'is, kus elutoas peegelseinad ja rohkesti reisidelt toodud meeneid, köögis aga katavad mööblikonstruktsioone keraamilised plaadid ja riiulite ees on kangad

  3. Designs for a quantum electron microscope.

    Science.gov (United States)

    Kruit, P; Hobbs, R G; Kim, C-S; Yang, Y; Manfrinato, V R; Hammer, J; Thomas, S; Weber, P; Klopfer, B; Kohstall, C; Juffmann, T; Kasevich, M A; Hommelhoff, P; Berggren, K K

    2016-05-01

    One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This 'quantum weirdness' could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or "quantum electron microscope". A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  4. RF Design of the TW Buncher for the CLIC Drive Beam Injector (2nd report)

    CERN Document Server

    Shaker, Hamed

    2016-01-01

    CLIC is based on the two beams concept that one beam (drive beam) produces the required RF power to accelerate another beam (main beam). The drive beam is produced and accelerated up to 50MeV inside the CLIC drive beam injector. The drive beam injector main components are a thermionic electron gun, three sub-harmonic bunchers, a pre-buncher, a TW buncher, 13 accelerating structures and one magnetic chicane. This document is the second report of the RF structure design of the TW buncher. This design is based on the beam dynamic design done by Shahin Sanaye Hajari due to requirements mentioned in CLIC CDR. A disk-loaded tapered structure is chosen for the TW buncher. The axial electric field increases strongly based on the beam dynamic requirements. This second report includes the study of HOM effects, retuning the cells, study of dimensional tolerances and the heat dissipation on the surface.

  5. Avaliação endócrina e morfológica de transplante ovariano homógeno Endocrine and morphological assessment of ovarian homologous transplantation

    Directory of Open Access Journals (Sweden)

    Andy Petroianu

    2004-06-01

    Full Text Available INTRODUÇÃO: A insuficiência ovariana decorre de ooforectomia bilateral em diversas afecções do ovário, como neoplasia e sepse, além de quimioterapia, radiação pélvica e fatores relacionados à idade. Suas complicações sistêmicas, como insuficiências hormonais, podem ser de difícil controle. OBJETIVOS: Avaliar aspectos endócrinos e histológicos ovarianos após seu transplante ortotópico, sem anastomose vascular e submetidos à imunossupressão pela ciclosporina. MATERIAL E MÉTODO: Foram utilizadas 12 coelhas da raça Nova Zelândia Branca (n = 6 e Califórnia (n = 6, divididas em dois grupos: grupo 1 (n = 4, de controle, submetido apenas a laparotomia, sem outro procedimento cirúrgico; e grupo 2 (n = 8, submetido a ooforectomia bilateral e transplante ortotópico dos ovários, que foram trocados entre as duas raças de animais. De um lado, foi transplantado o ovário íntegro e, do outro, o ovário fatiado. Não houve anastomose vascular. As coelhas foram imunossuprimidas com ciclosporina (10mg/kg ao dia. No final do período de acompanhamento de seis meses, foram feitas dosagens de estradiol, progesterona, hormônio foliculoestimulante (FSH e hormônio luteinizante (LH, além de estudo histológico de ovários, tuba uterina e útero. RESULTADOS: Os ovários transplantados estavam rodeados por tecido conjuntivo, bem vascularizados, mostrando folículos em diferentes estádios de desenvolvimento. A histologia tubária e uterina também foi preservada em ambos os grupos. A dosagem hormonal foi normal em todas as coelhas, indicando que, do ponto de vista endócrino, o ovário transplantado estava funcionando. O transplante ovariano homógeno ortotópico, sem pedículo vascular e submetido à imunossupressão pela ciclosporina, foi eficaz para a manutenção de hormônios ovarianos em níveis normais.INTRODUCTION: Ovarian failure may be due to bilateral oophorectomy on several ovarian diseases, such as infection and neoplasm

  6. DESIGN, PROTOTYPE AND MEASUREMENT OF A SINGLE-CELL DEFLECTING CAVITY FOR THE ADVANCED PHOTON SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Haipeng Wang, Guangfeng Cheng, Gianluigi Ciovati, Peter Kneisel, Robert Rimmer, Kai Tian, Larry Turlington, Alireza Nassiri, Geoff Waldschmidt

    2009-05-01

    After the design optimization of a squashed elliptical shape, single-cell, superconducting (SC) deflecting cavity at 2.815 GHz, a copper prototype has been bench measured to determine its rf properties and the effectiveness of waveguide damping of parasitic modes [1]. RF cold tests were also performed at 2K on niobium single-cell and two-cell prototype cavities. Details of impedance calculation using wakefiled analysis of the single-cell cavity are shown to meet the strict 200 mA beam stability requirement of the Advanced Photon Source (APS) at Argonne National Lab where a total of 16 single-cell cavities will be divided into two cryomodule. The design of higher-order mode (HOM) waveguide damping, the simulations of the Lorenz force detuning, and the prototype of on-cell damping are presented.

  7. Monolithically Integrated Fiber Optic Coupler

    Science.gov (United States)

    2013-01-14

    tilted Bragg gratings 24 are thermoelectric coolers ( TECs ) 30 that can modify the pitch of the tilted Bragg gratings 24, thereby changing their...sufficiently compact for the application. This can include fluid transfer heating/cooling devices and other electrical devices. TECs are preferred...light bending optical nano -structure 76 is formed in core 14 to reflect light 74 along an axis 35. The pitch of nano -structure 76 can be adjusted by

  8. RF Design Optimization for New Injector Cryounit at CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haipeng; Cheng, Guangfeng; Hannon, Fay E.; Hofler, Alicia S.; Kazimi, Reza; Preble, Joe; Rimmer, Robert A.

    2013-06-01

    A new injector superconducting RF (SRF) cryounit with one new 2-cell, B=0.6 cavity plus one refurbished 7-cell, B=0.97, C100 style cavity has been re-designed and optimized for the engineering compatibility of existing module for CEBAF operation. The optimization of 2-cell cavity shape for longitudinal beam dynamic of acceleration from 200keV to 533keV and the minimization of transverse kick due to the waveguide couplers to less than 1 mrad have been considered. Operating at 1497MHz, two cavities has been designed into a same footprint of CEBAF original quarter cryomodule to deliver an injection beam energy of 5MeV in less than 0.27{degree} rms bunch length and a maximum energy spread of 5keV.

  9. R & D on Very-High-Current Superconducting Proton Linac, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, Ilan [Stony Brook Univ., NY (United States)

    2013-03-31

    The aim of this R&D project was to develop a superconducting cavity for a very-­ high-current proton accelerator. The particular application motivating the proposal was a LHC upgrade called the Superconducting Proton Linac, or SPL. Under the grant awarded to Stony Brook University the cavity was designed, a prototype copper cavity, followed by the niobium cavity, were built. A new set of HOM dampers was developed. The cavity has outstanding RF performance parameters – low surface fields, low power loss and all HOMs are fully damped. In fact, it is a “universal cavity” in the sense that it is suited for the acceleration of high-­current protons and well as high current electrons. Its damping of HOM modes is so good that it can see service in a multi-pass linac or an Energy Recovery Linac in addition to the easier service in a single-pass linac. Extensive measurements were made on the cavities and couplers, with the exception of the cold test of the niobium cavity. At the time of this report the cavity has been chemically processed and is ready for vertical testing which will be carried out shortly.

  10. Implante de condrócitos homólogos em defeitos osteocondrais de cães: padronização da técnica e avaliação histopatológica Homologous articular chondrocytes implantation in osteochondral defects of dogs: technique and histopathological evaluation standardization

    Directory of Open Access Journals (Sweden)

    L.S. Iamaguti

    2013-02-01

    Full Text Available Padronizou-se a metodologia para cultura de condrócitos em cães e avaliou-se seu implante em lesões osteocondrais, utilizando-se a membrana biossintética de celulose (MBC como revestimento. Dez cães, adultos e clinicamente sadios, foram submetidos à artrotomia das articulações fêmoro-tíbio-patelares. Defeitos de 4mm de diâmetro e profundidade foram induzidos no sulco troclear de ambos os membros. MBC foi aplicada na base e na superfície das lesões. Os defeitos do membro direito foram preenchidos com condrócitos homólogos cultivados formando o grupo-tratado (GT; os do membro esquerdo, sem implante celular, foram designados grupo-controle (GC. A evolução pós-operatória foi analisada com especial interesse nos processos de reparação da lesão, por meio de histomorfometria e imuno-histoquímica para colágeno tipo II e sulfato de condroitina. A cultura de condrócitos homólogos apresentou alta densidade e taxa de viabilidade. Observou-se integridade do tecido neoformado com a cartilagem adjacente na avaliação histológica, em ambos os grupos. Na imuno-histoquímica, verificou-se predomínio de colágeno tipo II no GT. Morfometricamente, não houve diferença significativa entre o tecido fibroso e o fibrocartilaginoso entre os grupos. A cultura de condrócitos homólogos de cães foi exequível. O tecido neoformado apresentou qualidade discretamente superior associado ao implante homólogo de condrócitos, contudo não promoveu reparação por cartilagem hialina.The aim of the study is to standardize the methodology to achieve canine chondrocytes culture, and evaluate its implant on osteochondral defects made in the femoral trochlear sulcus of dogs, using the cellulose biosynthetic membrane (CBM as coating. Ten healthy adult dogs without locomotor disorders were used. All animals were submitted to arthrotomy of stifle joints and defects of four millimeters in diameter x four millimeters deep were done in the femoral trochlear

  11. Contribution à l'étude de l'écologie et de la biologie des homoptères ravageurs des arbres fruitiers et autres plantes I.- Comparaison de l'évolution des populations d'Aleurodicus dispersus Russell (Hom.: Aleyrodidae sur agrumes et avocatier en République du Congo

    Directory of Open Access Journals (Sweden)

    Kiyindou, A.

    2002-01-01

    Full Text Available Contribution to the Knowledge of the Ecology and Biology of Homopterous Pests of Fruit Trees and other Plants I.- Comparaison of Evolution of Population of Aleurodicus dispersus Russell (Hom.: Aleyrodidae on Citrus and Avocado Trees in the Republic of the Congo. Aleurodicus dispersus Russell, a whitefly of neotropical origin, was introduced into Congo in the early '90. Since 1995, A. dispersus has developped the important populations on Citrus and avocado trees. The study of the population dynamic of this whitefly on Citrus and avocado trees indicates that the pest exhibits only four and three generation a year on Citrus and avocado trees respectively. Besides, an increase of the population of A. dispersus occurs in the dry season. However, rainfall reduces the insect population to a very low level. Its abundance indicates that during the rainy season, A. dispersus appears ealier underpinned for the first time and its significance assessed.

  12. Aerosol-radiation interaction modelling using online coupling between the WRF 3.7.1 meteorological model and the CHIMERE 2016 chemistry-transport model, through the OASIS3-MCT coupler

    Science.gov (United States)

    Briant, Régis; Tuccella, Paolo; Deroubaix, Adrien; Khvorostyanov, Dmitry; Menut, Laurent; Mailler, Sylvain; Turquety, Solène

    2017-02-01

    The presence of airborne aerosols affects the meteorology as it induces a perturbation in the radiation budget, the number of cloud condensation nuclei and the cloud micro-physics. Those effects are difficult to model at regional scale as regional chemistry-transport models are usually driven by a distinct meteorological model or data. In this paper, the coupling of the CHIMERE chemistry-transport model with the WRF meteorological model using the OASIS3-MCT coupler is presented. WRF meteorological fields along with CHIMERE aerosol optical properties are exchanged through the coupler at a high frequency in order to model the aerosol-radiation interactions. The WRF-CHIMERE online model has a higher computational burden than both models run separately in offline mode (up to 42 % higher). This is mainly due to some additional computations made within the models such as more frequent calls to meteorology treatment routines or calls to optical properties computation routines. On the other hand, the overall time required to perform the OASIS3-MCT exchanges is not significant compared to the total duration of the simulations. The impact of the coupling is evaluated on a case study over Europe, northern Africa, the Middle East and western Asia during the summer of 2012, through comparisons of the offline and two online simulations (with and without the aerosol optical properties feedback) to observations of temperature, aerosol optical depth (AOD) and surface PM10 (particulate matter with diameters lower than 10 µm) concentrations. The result shows that using the optical properties feedback induces a radiative forcing (average forcing of -4.8 W m-2) which creates a perturbation in the average surface temperatures over desert areas (up to 2.6° locally) along with an increase in both AOD and PM10 concentrations.

  13. RF Design of the TW Buncher for the CLIC Drive Beam Injector

    CERN Document Server

    Shaker, H

    2015-01-01

    The CLIC is based on the two beams concept that one beam (drive beam) produces the required RF power to accelerate another beam (main beam). The drive beam is produced and accelerated up to 50MeV inside the CLIC drive beam injector. The drive beam injector main components are a thermionic electron gun, three sub harmonic bunchers, a pre-buncher, a TW buncher, 13 accelerating structures and one magnetic chicane. This document is the first report of the RF structure design of the TW buncher. This design is based on the beam dynamic design done by Shahin Sanaye Hajari due to requirements mentioned in CLIC CDR. A disk-loaded tapered structure is chosen for the TW buncher. The axial electric field increases strongly based on the beam dynamic requirements. This report includes the design of the power couplers. The fundamental mode beam loading and higher order modes effect were preliminary studied.

  14. Modeling and design of an X-band rf photoinjector

    Directory of Open Access Journals (Sweden)

    R. A. Marsh

    2012-10-01

    Full Text Available A design for an X-band rf photoinjector that was developed jointly by SLAC National Accelerator Laboratory (SLAC and Lawrence Livermore National Laboratory (LLNL is presented. The photoinjector is based around a 5.59 cell rf gun that has state-of-the-art features including: elliptical contoured irises; improved mode separation; an optimized initial half cell length; a racetrack input coupler; and coupling that balances pulsed heating with cavity fill time. Radio-frequency and beam dynamics modeling have been done using a combination of codes including PARMELA, HFSS, IMPACT-T, ASTRA, and the ACE3P suite of codes developed at SLAC. The impact of lower gradient operation, magnet misalignment, solenoid multipole errors, beam offset, mode beating, wakefields, and beam line symmetry have been analyzed and are described. Fabrication and testing plans at both LLNL and SLAC are discussed.

  15. A preliminary design of the collinear dielectric wakefield accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Zholents, A.; Gai, W.; Doran, S.; Lindberg, R.; Power, J.G.; Strelnikov, N.; Sun, Y.; Trakhtenberg, E.; Vasserman, I. [ANL, Argonne, IL 60439 (United States); Jing, C.; Kanareykin, A.; Li, Y. [Euclid Techlabs LLC, Solon, OH 44139 (United States); Gao, Q. [Tsinghua University, Beijing (China); Shchegolkov, D.Y.; Simakov, E.I. [LANL, Los Alamos, NM 87545 (United States)

    2016-09-01

    A preliminary design of the multi-meter long collinear dielectric wakefield accelerator that achieves a highly efficient transfer of the drive bunch energy to the wakefields and to the witness bunch is considered. It is made from ~0.5 m long accelerator modules containing a vacuum chamber with dielectric-lined walls, a quadrupole wiggler, an rf coupler, and BPM assembly. The single bunch breakup instability is a major limiting factor for accelerator efficiency, and the BNS damping is applied to obtain the stable multi-meter long propagation of a drive bunch. Numerical simulations using a 6D particle tracking computer code are performed and tolerances to various errors are defined.

  16. Beam position diagnostics with higher order modes in third harmonic superconducting accelerating cavities

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pei

    2013-02-15

    Higher order modes (HOM) are electromagnetic resonant fields. They can be excited by an electron beam entering an accelerating cavity, and constitute a component of the wakefield. This wakefield has the potential to dilute the beam quality and, in the worst case, result in a beam-break-up instability. It is therefore important to ensure that these fields are well suppressed by extracting energy through special couplers. In addition, the effect of the transverse wakefield can be reduced by aligning the beam on the cavity axis. This is due to their strength depending on the transverse offset of the excitation beam. For suitably small offsets the dominant components of the transverse wakefield are dipole modes, with a linear dependence on the transverse offset of the excitation bunch. This fact enables the transverse beam position inside the cavity to be determined by measuring the dipole modes extracted from the couplers, similar to a cavity beam position monitor (BPM), but requires no additional vacuum instrumentation. At the FLASH facility in DESY, 1.3 GHz (known as TESLA) and 3.9 GHz (third harmonic) cavities are installed. Wakefields in 3.9 GHz cavities are significantly larger than in the 1.3 GHz cavities. It is therefore important to mitigate the adverse effects of HOMs to the beam by aligning the beam on the electric axis of the cavities. This alignment requires an accurate beam position diagnostics inside the 3.9 GHz cavities. It is this aspect that is focused on in this thesis. Although the principle of beam diagnostics with HOM has been demonstrated on 1.3 GHz cavities, the realization in 3.9 GHz cavities is considerably more challenging. This is due to the dense HOM spectrum and the relatively strong coupling of most HOMs amongst the four cavities in the third harmonic cryo-module. A comprehensive series of simulations and HOM spectra measurements have been performed in order to study the modal band structure of the 3.9 GHz cavities. The dependencies of

  17. Calculation of Wakefields and Higher Order Modes for the New Design of the Vacuum Chamber of the CMS Experiment for the HL-LHC

    CERN Document Server

    Wanzenberg, R

    2013-01-01

    To extend the discovery potential of the Large Hadron Collider (LHC) a design study for a novel machine configuration, the High Luminosity LHC (HL-LHC), was started with the goal to increase its luminosity by a factor of 10 beyond its design value. The new machine configuration will also include an upgraded detector configuration and a new beam pipe in the CMS detector. The short range wakefields and the trapped Higher Order Modes (HOMs) for the new design of the vacuum chamber are calculated and compared with the presently used chamber. The kick and loss parameters are presented for different sets of beam parameters. The numerical calculations have been performed with the computer codes MAFIA and ECHO2D. The obtained data are intended to be included into the impedance database of the HL-LHC.

  18. Reparação da traquéia de cã o com segmaneto muscular homólogo de diafragma conservado em glicerina a 98% Canine tracheal repair with homologous diaphragmatic muscle fragment preserved in 98% glycerin

    Directory of Open Access Journals (Sweden)

    Alexandre Mazzanti

    2000-12-01

    Full Text Available A viabilidade de segmento muscular de diafragma homólogo conservado em solução de glicerina a 98% foi estudada na reparação da traquéia cervical de cães. Foram utilizados 18 cães, adultos, oito machos, sem raça definida com peso variando de 6 a 21kg. Cinco anéis traqueais (2,0 x 4,5cm foram removidos parcialmente para implantação de segmento muscular homólogo. Os animais foram separados em grupos de igual número e observados por um período de 15 dias (grupo I, 30 dias (grupo II e 60 dias (grupo III de pós-operatório (PO, quando foram reoperados para observaçõ es macroscópicas e coleta de amostras para avaliação histológica. Ocorreu reparação da lesão traqueal, com substituição progressiva do enxerto muscular por tecido conjuntivo fibroso unindo as extremidades das cartilagens traqueais do defeito, com migração epitelial na luz traqueal e presença de cílios. O segmento muscular de diafragma homólogo conservado em glicerina a 98% pode ser utilizado na reparaç ão de defeitos traqueais, pois oferece suporte temporário para formação de tecido conjuntivo fibroso, sem proliferação exagerada, e permite a epitelizaçã o na região do implante.The viability of a homologous diaphragmatic muscle preserved in 98% glycerin for cervical tracheal repair in dogs was studied. Eighteen adult mongrel dogs, eight males, weighting 6 to 21kg were used. Five tracheal rings (2.0 x 4.5cm were partially resected and a homologous muscle fragment was implanted. The animals were distributed in three numerally equal groups. They were observed for a post-operative period of 15 days (group I, 30 days (group II and 60 days (group III. After these periods, the dogs were reoperated for macroscopic evaluation and collection of samples for histological evaluations. Tracheal repair with progressive substitution of the muscle flap by fibrous connective tissue, epithelial migration through the tracheal lumen and presence of cilia were detected

  19. Design Methodology - Design Synthesis

    DEFF Research Database (Denmark)

    Andreasen, Mogens Myrup

    2003-01-01

    Design Methodology is part of our practice and our knowledge about designing, and it has been strongly supported by the establishing and work of a design research community. The aim of this article is to broaden the reader¿s view of designing and Design Methodology. This is done by sketching...... the development of Design Methodology through time and sketching some important approaches and methods. The development is mainly forced by changing industrial condition, by the growth of IT support for designing, but also by the growth of insight into designing created by design researchers.......ABSTRACT Design Methodology shall be seen as our understanding of how to design; it is an early (emerging late 60ies) and original articulation of teachable and learnable methodics. The insight is based upon two sources: the nature of the designed artefacts and the nature of human designing. Today...

  20. A complete design flow for silicon photonics

    Science.gov (United States)

    Pond, James; Cone, Chris; Chrostowski, Lukas; Klein, Jackson; Flueckiger, Jonas; Liu, Amy; McGuire, Dylan; Wang, Xu

    2014-05-01

    Broad adoption of silicon photonics technology for photonic integrated circuits requires standardized design flows that are similar to what is available for analog and mixed signal electrical circuit design. We have developed a design flow that combines mature electronic design automation (EDA) software with optical simulation software. An essential component of any design flow, whether electrical or photonic, is the ability to accurately simulate largescale circuits. This is particularly important when the behavior of the circuit is not trivially related to the individual component performance. While this is clearly the case for electronic circuits consisting of hundreds to billions of transistors, it is already becoming important in photonic circuits such as WDM transmitters, where signal cross talk needs to be considered, as well as optical cross-connect switches. In addition, optical routing to connect different components requires the introduction of additional waveguide sections, waveguide bends, and waveguide crossings, which affect the overall circuit performance. Manufacturing variability can also have dramatic circuit-level consequences that need to be simulated. Circuit simulations must rely on compact models that can accurately represent the behavior of each component, and the compact model parameters must be extracted from physical level simulation and experimental results. We show how large scale circuits can be simulated in both the time and frequency domains, including the effects of bidirectional and, where appropriate, multimode and multichannel photonic waveguides. We also show how active, passive and nonlinear individual components such as grating couplers, waveguides, splitters, filters, electro-optical modulators and detectors can be simulated using a combination of electrical and optical algorithms, and good agreement with experimental results can be obtained. We then show how parameters, with inclusion of fabrication process variations, can

  1. Design and construction of drift tube linac cavities for RIKEN RI Beam Factory

    Science.gov (United States)

    Suda, K.; Sakamoto, N.; Yamada, K.; Arai, S.; Chiba, Y.; Kase, M.; Okuno, H.; Watanabe, Y.; Kamigaito, O.

    2013-09-01

    A new injector linac "RILAC2", has recently been constructed at the RIKEN RI Beam Factory. The main part of the RILAC2 is a drift tube linac that consists of three newly designed cavities. These cavities operate in continuous wave (CW) mode at a fixed frequency of 36.5 MHz. Their structure is based on a quarter-wavelength resonator because this is the smallest resonator available in this frequency range among the available structures. We adopted the direct coupling method in the construction of these cavities. A power amplifier was directly coupled to the cavity without a long transmission line to reduce the installation area and simultaneously reduce construction cost. A detailed cavity and coupler design was carried out via simulation. Our work also describes the design process using three-dimensional electromagnetic simulation software. Construction and operation tests are also shown.

  2. Designing Communication Design

    OpenAIRE

    LØVLIE, Anders Sundnes

    2016-01-01

    Innovating in the field of new media genres requires methods for producing designs that can succeed in being disseminated and used outside of design research labs. This article uses the author's experiences with the development of university courses in communication design to address the research question: How can we design courses to give students the competencies they need to work as designers of new media? Based on existing approaches from UX design and other fields, I present a model that...

  3. Designing Communication Design

    DEFF Research Database (Denmark)

    Løvlie, Anders Sundnes

    2016-01-01

    Innovating in the field of new media genres requires methods for producing designs that can succeed in being disseminated and used outside of design research labs. This article uses the author's experiences with the development of university courses in communication design to address the research...... question: How can we design courses to give students the competencies they need to work as designers of new media? Based on existing approaches from UX design and other fields, I present a model that has demonstrated its usefulness in the development of commercial products and services. The model...

  4. Designing Material Materialising Design

    DEFF Research Database (Denmark)

    Nicholas, Paul

    2013-01-01

    and operational models by which to specify and materialise causal relationships between configuration and transformation, these investigations reveal a new locus for architectural instruction that requires new kinds of design information, new representational models, and different modes of design control.......Designing Material Materialising Design documents five projects developed at the Centre for Information Technology and Architecture (CITA) at the Royal Danish Academy of Fine Arts, School of Architecture. These projects explore the idea that new designed materials might require new design methods....... Focusing on fibre reinforced composites, this book sustains an exploration into the design and making of elastically tailored architectural structures that rely on the use of computational design to predict sensitive interdependencies between geometry and behaviour. Developing novel concepts...

  5. Design and realization of an all-fiber broadband tunable gain equalization filter for DWDM signals.

    Science.gov (United States)

    Varshney, R K; Nagaraju, B; Singh, A; Pal, B P; Kar, A K

    2007-10-17

    Design and fabrication of a tunable gain equalization filter for dense wavelength division multiplexed (DWDM) signals through erbium doped fiber amplifiers (EDFA) is reported. It is based on a side-polished fiber (SPF) half-coupler block loaded with a displaceable tapered multimode overlay waveguide (MMOW). A simple and accurate normal mode analysis is employed to design this filtering device for its subsequent realization. Equalization of a typical EDFA gain spectrum in the C-band within +/-0.35 dB or even less in the presence of various ITU standard C-band DWDM signal channels is demonstrated under varied operating conditions like add/drop of signals. Tunability of the filter notch is achieved through displacement of the SPF relative to the MMOW.

  6. RF design of a C-band compact spherical RF pulse compressor for SXFEL

    Science.gov (United States)

    Li, Zongbin; Fang, Wencheng; Gu, Qiang; Zhao, Zhentang

    2017-08-01

    A new C-band (5712 MHz) compact spherical radio frequency (RF) pulse compressor was designed for the Soft X-ray Free Electron Laser facility (SXFEL) at the Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Sciences (CAS). Using only one high Q0 spherical RF resonant cavity which works on two TE113 modes and a dual-mode polarized coupler, this pulse compressor could achieve an average power gain of 3.8. Associated with the C-band accelerator, an energy gain of 1.85 with the coupling coefficient of 4.9 could be achieved. Particularly it could make the output power stable. This paper presents the scheme of the C-band spherical pulse compressor, as well as the RF design and details of the frequency sensitivities and machining considerations.

  7. How Expert Designers Design

    NARCIS (Netherlands)

    Dr. Peter Sloep; J. van Merrienboer; C. Carr; P. Kirschner

    2003-01-01

    This paper discusses two studies - the one in a business context, the other in a university context - carried out with expert educational designers. The studies aimed to determine the priorities experts claim to employ when designing competence-based learning environments. Designers in both contexts

  8. Design of 6 MeV X-band electron linac for dual-head gantry radiotherapy system

    Science.gov (United States)

    Shin, Seung-wook; Lee, Seung-Hyun; Lee, Jong-Chul; Kim, Huisu; Ha, Donghyup; Ghergherehchi, Mitra; Chai, Jongseo; Lee, Byung-no; Chae, Moonsik

    2017-12-01

    A compact 6 MeV electron linac is being developed at Sungkyunkwan University, in collaboration with the Korea atomic energy research institute (KAERI). The linac will be used as an X-ray source for a dual-head gantry radiotherapy system. X-band technology has been employed to satisfy the size requirement of the dual-head gantry radiotherapy machine. Among the several options available, we selected a pi/2-mode, standing-wave, side-coupled cavity. This choice of radiofrequency (RF) cavity design is intended to enhance the shunt impedance of each cavity in the linac. An optimum structure of the RF cavity with a high-performance design was determined by applying a genetic algorithm during the optimization procedure. This paper describes the detailed design process for a single normal RF cavity and the entire structure, including the RF power coupler and coupling cavity, as well as the beam dynamics results.

  9. Cavity Design, Fabrication and Commission Performance of a 750MHz, 4-rod Separator for CEBAF 4-Hall Beam Delivery System

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haipeng [Jefferson Lab, Newport News, VA; Cheng, Guangfeng [Jefferson Lab, Newport News, VA; Turlington, Larry T. [Jefferson Lab, Newport News, VA; Wissmann, Mark J. [Jefferson Lab, Newport News, VA

    2015-09-01

    A short version of the original CEBAF normal conducting 4-rod separator cavity has been developed into a 750MHz one * since the concept of simultaneous 4-hall operation for CEBAF is introduced **. This work has been advanced further based on the EM design optimization, bench measurement and by conducting RF-thermal coupled simulation using CST and ANSYS to confirm the cavity tuning and thermal performance. The cavity fabrication used matured technology like copper plating and machining. The cavity flanges, couplers, tuners and cooling channels adopted consistent/compatible hardware with the existing 500MHz cavities. The electromagnetic and thermal design simulations have greatly reduced the prototyping and bench tuning time of the first prototype. Four production cavities have reached a typical 1.94MV kick voltage or 3.0kW wall loss on each cavity after a minor multipactoring or no processing, 7.5% overhead power than the design specification.

  10. Passive Microwave Component Design Using Inverse Scattering: Theory and Applications

    Directory of Open Access Journals (Sweden)

    Israel Arnedo

    2013-01-01

    Full Text Available We briefly review different synthesis techniques for the design of passive microwave components with arbitrary frequency response, developed by our group during the last decade. We provide the theoretical foundations based on inverse scattering and coupled-mode theory as well as several applications where the devices designed following those techniques have been successfully tested. The main characteristics of these synthesis methods are as follows. (a They are direct, because it is not necessary to use lumped-element circuit models; just the target frequency response is the starting point. (b They are exact, as there is neither spurious bands nor degradation in the frequency response; hence, there is no bandwidth limitation. (c They are flexible, because they are valid for any causal, stable, and passive transfer function; only inviolable physical principles must be guaranteed. A myriad of examples has been presented by our group in many different technologies for very relevant applications such as harmonic control of amplifiers, directional coupler with enhanced directivity and coupling, transmission-type dispersive delay lines for phase engineering, compact design of high-power spurious free low-pass waveguide filters for satellite payloads, pulse shapers for advanced UWB radar and communications and for novel breast cancer detection systems, transmission-type Nth-order differentiators for tunable pulse generation, and a robust filter design tool.

  11. Status of higher order mode beam position monitors in 3.9 GHz superconducting accelerating cavities at FLASH

    CERN Document Server

    Zhang, P; Jones, R M; Flisgen, T; Van Rienen, U; Shinton, I R R

    2013-01-01

    Higher order mode (HOM) beam position monitors (BPM) are being developed for the 3.9 GHz third harmonic superconducting accelerating cavities at FLASH. The transverse beam position in a cavity can be determined utilizing beam-excited HOMs based on dipole components. The existing couplers used for HOM suppression provide necessary signals. The diagnostics principle is similar to a cavity BPM, but requires no additional vacuum instruments on the linac. The challenges of HOM-BPM for 3.9 GHz cavities lie in the dense HOM spectrum arising from the coupling of the majority HOMs amongst the four cavities in the cryo-module ACC39. HOMs with particularly promising diagnostics features were evaluated using a spectrum analyzer and custom-built test electronics with various data analysis techniques, data reduction was focused on. After careful theoretical and experimental assessment of the HOM spectrum, multi-cavity modes in the region of 5 GHz were chosen to provide a global position over the complete module with superi...

  12. Prompting Designers to Design

    DEFF Research Database (Denmark)

    Ahmed, Saeema

    2006-01-01

    Recent research suggest that engineering designers need assistance to understand what information is relevant for their particular design problem. They require guidance in formulating their queries and also to understand what information is relevant for them. This paper presents an approach...... to prompt designers with their design queries. A method that automatically extracts relationships between concepts is described, along with some examples. The method can be implemented as part of knowledge management system and the relationships are extracted form documents that are indexed within...... the system. The distinctive features of this approach is that all the concepts are elicited from the minds of engineering designers, and the system builds up knowledge as more documents enter the system. The approach is based on an understanding obtained from a number of empirical studies and also from...

  13. Prompting Designers to Design

    DEFF Research Database (Denmark)

    Ahmed, Saeema

    2007-01-01

    to prompt designers with their design queries. A method that automatically extracts relationships between concepts is described, along with some examples. The method can be implemented as part of knowledge management system and the relationships are extracted form documents that are indexed within...... the system. The distinctive features of this approach is that all the concepts are elicited from the minds of engineering designers, and the system builds up knowledge as more documents enter the system. The approach is based on an understanding obtained from a number of empirical studies and also from...

  14. Design and simulation of integrated optical interferometers fabricated in polymer foils

    Science.gov (United States)

    Xiao, Yanfen; Hofmann, Meike; Zappe, Hans

    2015-02-01

    Integrated optical Mach-Zehnder interferometers (MZI) can be used as high sensitivity sensors through the interaction of the evanescent field of the waveguide with liquids or gases surrounding the sensor. We present here the design of polymer-based MZIs fabricated by hot-embossing and printing technologies. Simulations of an integrated MZI system with regard to variations of the waveguide cross-section and the refractive indices of the core layer are carried out to guarantee single mode behavior and optimize high sensitivity to external refractive index changes of analytes. The simulation of propagation losses induced by the Y-coupleres is also presented. Furthermore, transmission as a function of different interaction window lengths are also simulated on the entire MZI structure using a mixture of water and ethanol as an analyte on the sensing arm. Finally, we calculate the coupling efficiency of a laser diode into a tapered waveguide and estimate that a value of 30% is possible.

  15. Dansk Design

    DEFF Research Database (Denmark)

    Dickson, Thomas

    Indhold: Hvad er design?; Hvor kommer dansk design fra?; Produktdesign; Tekstil- og tøjdesign; Design af møbler og boligindretning; Bygningen og design; Arbejdets design; Transportdesign; Offentligt design; Grafisk design; Nye tider og en ny slags design...

  16. On the “Cracking” Scheme in the Paper “A Directional Coupler Attack Against the Kish Key Distribution System” by Gunn, Allison and Abbott

    Directory of Open Access Journals (Sweden)

    Chen Hsien-Pu

    2014-08-01

    Full Text Available Recently, Gunn, Allison and Abbott (GAA [http://arxiv.org/pdf/1402.2709v2.pdf] proposed a new scheme to utilize electromagnetic waves for eavesdropping on the Kirchhoff-law-Johnson-noise (KLJN secure key distribution. We proved in a former paper [Fluct. Noise Lett. 13 (2014 1450016] that GAA’s mathematical model is unphysical. Here we analyze GAA’s cracking scheme and show that, in the case of a loss-free cable, it provides less eavesdropping information than in the earlier (Bergou-Scheuer-Yariv mean-square-based attack [Kish LB, Scheuer J, Phys. Lett. A 374:2140-2142 (2010], while it offers no information in the case of a lossy cable. We also investigate GAA’s claim to be experimentally capable of distinguishing—using statistics over a few correlation times only—the distributions of two Gaussian noises with a relative variance difference of less than 10-8. Normally such distinctions would require hundreds of millions of correlations times to be observable. We identify several potential experimental artifacts as results of poor KLJN design, which can lead to GAA’s assertions: deterministic currents due to spurious harmonic components caused by ground loops, DC offset, aliasing, non-Gaussian features including non-linearities and other non-idealities in generators, and the timederivative nature of GAA’s scheme which tends to enhance all of these artifacts.

  17. Design and fabrication of the 2 × 4-cell superconducting linac module for the free-electron laser

    Science.gov (United States)

    Luo, Xing; Lao, Chenglong; Zhou, Kui; Li, Ming; Yang, Xingfan; Lu, Xiangyang; Quan, Shengwen; Wang, Fang; Mi, Zhenghui; Sun, Yi; Wang, Hanbin; Shan, Lijun; He, Tianhui

    2017-11-01

    A 2 × 4-cell superconducting linac module for the THz-FEL facility has been developed at the China Academy of Engineering Physics, which is expected to provide 6-8 MeV quasi-CW electron beams with an average current of 1-5 mA. The module consists of two 4-cell SRF cavities, two main couplers, two tuners and a cryostat. The design, fabrication and performance test of these components is presented in this paper. The test results reveal that all these components have reached their design goals and the module has also been assembled and horizontal tested at Chengdu. The gradients of both cavities at 2 K reach 10 MV/m, which meets our requirements. Currently beam-loading commissioning is underway.

  18. Designing and being designed

    DEFF Research Database (Denmark)

    Bogers, Marcel; Ollila, Susanne; Yström, Anna

    2016-01-01

    Societal challenges are inherently complex societal problems that cannot be solved using traditional innovation management approaches. Instead, collaborative governance is needed to enable the inter-organizational arrangements that are required to address a societal challenge. In this study we...... explore, applying a design perspective, which governance practices are used and how they are used to foster the necessary collaborations in the context of such complex innovation. Our case study of the societal challenge related to the Swedish traffic safety environment reveals two linked design processes...... in which the governance practices are used for continuous re-framing and re-designing of the collaboration as well as the societal challenge. We propose a model for collaborative governance in the context of a complex innovation that highlights path-creating, identity creating and meaning making as central...

  19. Design of the 3.7 GHz, 500 kW CW circulator for the LHCD system of the SST-1 tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Dixit, Harish V., E-mail: hvdixit48@yahoo.com [Veermata Jijabai Technological Institute, Mumbai, Maharashtra 400019 (India); Jadhav, Aviraj R. [Veermata Jijabai Technological Institute, Mumbai, Maharashtra 400019 (India); Jain, Yogesh M. [Institute for Plasma Research, Gandhinagar, Gujarat 382428 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094 (India); Cheeran, Alice N. [Veermata Jijabai Technological Institute, Mumbai, Maharashtra 400019 (India); Gupta, Vikas [Vidyavardhini' s College of Engineering and Technology, Vasai, Maharashtra 401202 (India); Sharma, P.K. [Institute for Plasma Research, Gandhinagar, Gujarat 382428 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094 (India)

    2017-06-15

    Highlights: • Design of a 500 kW CW circulator for LHCD system at 3.7 GHz. • Mechanism for thermal management of ferrite tile. • Scheme for uniform magnetisation of the ferrite tiles. • Design of high CW power CW quadrature and 180 ° hybrid coupler. - Abstract: Circulators are used in high power microwave systems to protect the vacuum source against reflection. The Lower Hybrid Current Drive (LHCD) system of SST-1 tokamak commissioned at IPR, Gandhinagar in India comprises of four high power circulators to protect klystrons (supplying 500 kW CW each at 3.7 GHz) which power the system. This paper presents the design of a Differential Phase Shift Circulator (DPSC) capable of handling 500 kW CW power at 3.7 GHz so that four circulators can be used to protect the four available klystrons. As the DPSC is composed by three main components, viz., magic tee, ferrite phase shifter and 3 dB hybrid coupler, the designing of each of the proposed components is described. The design of these components is carried out factoring various multiphysics aspects of RF, heating due to high CW power and magnetic field requirement of the ferrite phase shifter. The primary objective of this paper is to present the complete RF, magnetic and thermal design of a high CW power circulator. All the simulations have been carried out in COMSOL Multiphysics. The designed circulator exhibits an insertion loss of 0.13 dB with a worst case VSWR of 1.08:1. The total length of the circulator is 3 m.

  20. A Thermally Tunable 1 × 4 Channel Wavelength Demultiplexer Designed on a Low-Loss Si3N4 Waveguide Platform

    Directory of Open Access Journals (Sweden)

    Mohammed Shafiqul Hai

    2015-11-01

    Full Text Available A thermally tunable 1 × 4 channel optical demultiplexer was designed using an ultra low-loss Si3N4 (propagation loss ~3.1 dB/m waveguide. The demultiplexer has three 2 × 2 Mach-Zehnder interferometers (MZI, where each of the MZI contains two 2 × 2 general interference based multimode interference (MMI couplers. The MMI couplers exhibit −3.3 dB to −3.7 dB power division ratios over a 50 nm wavelength range from 1530 nm to 1580 nm. The chrome-based (Cr heaters placed on the delay arms of the MZI filters enable thermal tuning to control the optical phase shift in the MZI delay arms. This facilitates achieving moderately low crosstalk (14.5 dB between the adjacent channels. The optical insertion loss of the demultiplexer per channel is between 1.5 dB to 2.2 dB over the 1550 nm to 1565 nm wavelength range. Error free performance (BER of 10−12 is obtained for all four 40 Gb/s data rate channels. The optical demultiplexer is an important tool towards building photonic integrated circuits with complex optical signal processing functionalities in the low-loss Si3N4 waveguide platform.

  1. Single-mode laser studies: Design and performance of a fixed-wave length source and coupling of lasers to thin-film optical waveguides

    Science.gov (United States)

    Ladany, I.; Hammer, J. M.

    1980-01-01

    A module developed for the generation of a stable single wavelength to be used for a fiber optic multiplexing scheme is described. The laser is driven with RZ pulses, and the temperature is stabilized thermoelectrically. The unit is capable of maintaining a fixed wavelength within about 6 A as the pulse duty cycle is changed between 0 and 100 percent. This is considered the most severe case, and much tighter tolerances are obtainable for constant input power coding schemes. Using a constricted double heterostructure laser, a wavelength shift of 0.083 A mA is obtained due to laser self-heating by a dc driving current. The thermoelectric unit is capable of maintaining a constant laser heat-sink temperature within 0.02 C. In addition, miniature lenses and couplers are described which allow efficient coupling of single wavelength modes of junction lasers to thin film optical waveguides. The design of the miniature cylinder lenses and the prism coupling techniques allow 2 mW of single wavelength mode junction laser light to b coupled into thin film waveguides using compact assemblies. Selective grating couplers are also studied.

  2. Matriz óssea homóloga desmineralizada na preparação de falhas ósseas segmentares produzidas no rádio de coelhos Repair of segmental defects produced in the radii rabbit by homologous demineralized bone matrix

    Directory of Open Access Journals (Sweden)

    Alessandra Maria da Silva

    2003-06-01

    Full Text Available No presente trabalho, foram avaliados os potenciais osteoindutor e osteocondutor da matriz óssea homóloga desmineralizada (MOD em ácido clorídrico 0,6 N e conservada em etanol 70% e sua utilização no preenchimento de falhas osteoperiosteais induzidas em rádio de coelhos. O rádio operado de todos os animais foi radiografado imediatamente após a cirurgia e na 3ª,6ª, 9ª e 12ª semanas após. No grupo tratado, sete animais foram sacrificados a cada três semanas, sendo realizadas tomografia computadorizada e avaliações macro e microscópica e da fluorescência óssea à tetraciclina. Os animais do grupo controle foram sacrificados na 12ª semana de pós-operatório. Foi constatado que a matriz acelerou o processo de formação óssea, devido a fatores indutores inerentes que atuaram sobre as células dos tecidos adjacentes e que os canais vasculares, as lacunas e o canal medular vazios da MOD, serviram de arcabouço para a penetração celular, determinando osteocondução.In order to evaluate osteoinduction and osteoconduction of the homologous demineralized bone matrix (DBM, processed in HCl 0.6 N solution for 24 hours and preserved in 70% ethanol solution, radial fragments were implanted in radius of adults rabbits. The animals were sacrificed at 3, 6, 9 and 12 post-operative weeks and the control group was sacrificed in 12 post-operative weeks. Radiographic exams of the operated radii were performed immediately after surgery and 3, 6, 9 and 12 post-operative weeks. After euthanasia, computed tomography, macroscopic, microscopic and tetracycline fluorescence exams were performed. DBM preserved its osteoinductive property and remains sterile. The empty spaces are favorable to osteoconduction and its growth factors induce osseous formation.

  3. Design automation for integrated nonlinear logic circuits (Conference Presentation)

    Science.gov (United States)

    Van Vaerenbergh, Thomas; Pelc, Jason; Santori, Charles; Bose, Ranojoy; Kielpinski, Dave; Beausoleil, Raymond G.

    2016-05-01

    A key enabler of the IT revolution of the late 20th century was the development of electronic design automation (EDA) tools allowing engineers to manage the complexity of electronic circuits with transistor counts now reaching into the billions. Recently, we have been developing large-scale nonlinear photonic integrated logic circuits for next generation all-optical information processing. At this time a sufficiently powerful EDA-style software tool chain to design this type of complex circuits does not yet exist. Here we describe a hierarchical approach to automating the design and validation of photonic integrated circuits, which can scale to several orders of magnitude higher complexity than the state of the art. Most photonic integrated circuits developed today consist of a small number of components, and only limited hierarchy. For example, a simple photonic transceiver may contain on the order of 10 building-block components, consisting of grating couplers for photonic I/O, modulators, and signal splitters/combiners. Because this is relatively easy to lay out by hand (or simple script) existing photonic design tools have relatively little automation in comparison to electronics tools. But demonstrating all-optical logic will require significantly more complex photonic circuits containing up to 1,000 components, hence becoming infeasible to design manually. Our design framework is based off Python-based software from Luceda Photonics which provides an environment to describe components, simulate their behavior, and export design files (GDS) to foundries for fabrication. At a fundamental level, a photonic component is described as a parametric cell (PCell) similarly to electronics design. PCells are described by geometric characteristics of their layout. A critical part of the design framework is the implementation of PCells as Python objects. PCell objects can then use inheritance to simplify design, and hierarchical designs can be made by creating composite

  4. Design of RF system for CYCIAE-230 superconducting cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Zhiguo, E-mail: bitbearAT@hotmail.com; Ji, Bin; Fu, Xiaoliang; Cao, Xuelong; Zhao, Zhenlu; Zhang, Tinajue

    2017-05-11

    The CYCIAE230 is a low-current, compact superconducting cyclotron designed for proton therapy. The Radio Frequency system consists of four RF cavities and applies second harmonic to accelerate beams. The driving power for the cavity system is estimated to be approximately 150 kW. The LLRF controller is a self-made device developed and tested at low power using a small-scale cavity model. In this paper, the resonator systems of an S.C. cyclotron in history are reviewed. Contrary to those RF systems, the cavities of the CYCIAE230 cyclotron connect two opposite dees. Two high-power RF windows are included in the system. Each window carries approximately 75 kW RF power from the driver to the cavities. Thus, the RF system for the CY-CIAE230 cyclotron is operated in driven push–pull mode. The two-way amplifier-coupler-cavity systems are operated with approximately the same amount of RF power but 180° out of phase compared with each other. The design, as well as the technical advantage and limitations of this operating mode, of the CYCIAE230 cyclotron RF system is analyzed.

  5. Design of RF system for CYCIAE-230 superconducting cyclotron

    Science.gov (United States)

    Yin, Zhiguo; Ji, Bin; Fu, Xiaoliang; Cao, Xuelong; Zhao, Zhenlu; Zhang, Tinajue

    2017-05-01

    The CYCIAE230 is a low-current, compact superconducting cyclotron designed for proton therapy. The Radio Frequency system consists of four RF cavities and applies second harmonic to accelerate beams. The driving power for the cavity system is estimated to be approximately 150 kW. The LLRF controller is a self-made device developed and tested at low power using a small-scale cavity model. In this paper, the resonator systems of an S.C. cyclotron in history are reviewed. Contrary to those RF systems, the cavities of the CYCIAE230 cyclotron connect two opposite dees. Two high-power RF windows are included in the system. Each window carries approximately 75 kW RF power from the driver to the cavities. Thus, the RF system for the CY-CIAE230 cyclotron is operated in driven push-pull mode. The two-way amplifier-coupler-cavity systems are operated with approximately the same amount of RF power but 180° out of phase compared with each other. The design, as well as the technical advantage and limitations of this operating mode, of the CYCIAE230 cyclotron RF system is analyzed.

  6. Computer Aided Design and Analysis of a 2-4 GHz Broadband Balanced Microstrip Amplifier

    Directory of Open Access Journals (Sweden)

    S. H. Ibrahim

    2012-07-01

    Full Text Available In this paper, a computer-aided design and analysis of a 2-4 GHz broadband balanced microstrip amplifier using a full computer simulation program developed by the author and others is presented. A short and efficient CAD procedure for broadband amplifier design is introduced. The first step is to design an initial narrow-band high gain microstrip amplifier at 3-GHz central frequency. The second step is to optimize the initial lengths and widths of the input and output microstrip-matching circuits to get the broadband amplifier over the range 2-4 GHz. The analysis of both narrow and broadband amplifiers is investigated. In addition, with the design and analysis of a low-pass microstrip filter, the paper introduces the design and analysis of a Lange coupler. The final AC schematic diagram of the designed amplifier with the lengths and widths of microstrip lines is presented.Key Words: Computer-Aided Design and Analysis, Microstrip Amplifier, Microwave Amplifier.

  7. VLSI design

    CERN Document Server

    Chandrasetty, Vikram Arkalgud

    2011-01-01

    This book provides insight into the practical design of VLSI circuits. It is aimed at novice VLSI designers and other enthusiasts who would like to understand VLSI design flows. Coverage includes key concepts in CMOS digital design, design of DSP and communication blocks on FPGAs, ASIC front end and physical design, and analog and mixed signal design. The approach is designed to focus on practical implementation of key elements of the VLSI design process, in order to make the topic accessible to novices. The design concepts are demonstrated using software from Mathworks, Xilinx, Mentor Graphic

  8. Remoção da cartilagem articular associada ou não a implante homógeno ou enxerto autógeno de osso esponjoso em cães submetidos à artrodese atlantoaxial Joint cartilage removal associated or not to homologous implant or autologous cancellous bone graft in dogs submitted to atlantoaxial arthrodesis

    Directory of Open Access Journals (Sweden)

    Rafael Festugatto

    2013-03-01

    Full Text Available O objetivo deste estudo foi avaliar o grau de fusão articular e formação óssea na articulação atlantoaxial de cães submetidos à artrodese após a remoção da cartilagem articular associada ou não ao implante homógeno ou enxerto autógeno de osso esponjoso. Foram utilizados 12 cães, adultos, distribuídos aleatoriamente em três grupos iguais. Grupo I (GI: realizada apenas a remoção da cartilagem articular e imobilização articular com pinos e resina acrílica. Grupo II (GII: feita a remoção da cartilagem articular e imobilização da articulação, seguida da colocação e modelagem do implante ósseo esponjoso homógeno entre as superfícies articulares. Grupo III (GIII: foi realizado o mesmo procedimento do GII, mais o enxerto ósseo esponjoso autógeno no local determinado. Realizaram-se exames radiográficos em todos os animais aos 30, 60 e 90 dias de pós-operatório (PO. Aos 90 dias de PO foi feita a eutanásia para o emprego do teste de palpação manual, avaliação tomográfica e histopatológica. Para análise estatística da associação entre o grau de fusão articular, aplicou-se o Teste Qui-quadrado de independência. Os resultados dos testes foram avaliados pela significância exata e considerados significantes a 5% (PThe aim of this study was to evaluate the degree of joint fusion and bone formation in dogs undergoing atlantoaxial arthrodesis after removal of articular cartilage associated or not to implant homogenous or autogenous cancellous bone. Twelve dogs, weighing between 8 and 12kg were randomly divided into three groups. Group I (GI performed only the removal of joint cartilage and joint immobilization with acrylic resin and pins. Group II (GII: after removel of joint cartilage and articular immobilization was performed modeling and placement of homogenous cancellous bone at the given location. The volume of homograft placed in the joint was measured using a precision balance and all animals received the

  9. La nochebuena contada en lenguaje homérico

    Directory of Open Access Journals (Sweden)

    Manuel Briceño Jáuregui

    1983-01-01

    Full Text Available ...Así dijo el largovidente Dios, y a sus palabras se estremeció el dilatado Olimpo. Ya en aquel tiempo los que habían podido escapar de la espantosa muerte moraban en sus hogares, sin acordarse de los peligros de la guerra ni del insondable mar. Mas con los años llegó por fin el tiempo de cumplirse el divinal decreto, aunque no por eso debían los hombres poner fin a sus trabajos, ni siquiera después de la venida del Ungido. Y los bienaventurados habitantes del empíreo les compadecían, a excepción de Luzbel, que permaneció constantemente irritado en su corazón contra los mortales que se alimentan de pan hasta que no llegaran a la mansión del Hades.

  10. Design of a higher harmonic RF system for the Advanced Light Source

    CERN Document Server

    Byrd, J M; De Santis, S; Kosta, S; Lo, C C; Plate, D; Rimmer, R A; Franks, M

    2000-01-01

    We report on the design and fabrication of a third harmonic radiofrequency (RF) system for the Advanced Light Source (ALS) to be used for lengthening the bunch and increasing the Touschek-dominated beam lifetime. We plan to install five single-cell 1.5 GHz copper RF cavities in one-half of an ALS straight section with a predicted increase in the lifetime by a factor of 3. Each RF cell is designed to sustain a maximum voltage of 125 kV with a power dissipation of 5 kW. We present measurements made on an aluminum cavity model characterizing the RF properties of cavity such as the cavity R/Q and higher-order modes (HOMs). In particular, resonances in the cavity tuners were studied in order to avoid heating of the tuner bellows. Initial measurements of the copper cavities indicate a Q value of 21 000, resulting in a shunt impedance of 1.69 M OMEGA per cell

  11. Fiber coupler end face wavefront surface metrology

    Science.gov (United States)

    Compertore, David C.; Ignatovich, Filipp V.; Marcus, Michael A.

    2015-09-01

    Despite significant technological advances in the field of fiber optic communications, one area remains surprisingly `low-tech': fiber termination. In many instances it involves manual labor and subjective visual inspection. At the same time, high quality fiber connections are one of the most critical parameters in constructing an efficient communication link. The shape and finish of the fiber end faces determines the efficiency of a connection comprised of coupled fiber end faces. The importance of fiber end face quality becomes even more critical for fiber connection arrays and for in the field applications. In this article we propose and demonstrate a quantitative inspection method for the fiber connectors using reflected wavefront technology. The manufactured and polished fiber tip is illuminated by a collimated light from a microscope objective. The reflected light is collected by the objective and is directed to a Shack-Hartmann wavefront sensor. A set of lenses is used to create the image of the fiber tip on the surface of the sensor. The wavefront is analyzed by the sensor, and the measured parameters are used to obtain surface properties of the fiber tip, and estimate connection loss. For example, defocus components in the reflected light indicate the presence of bow in the fiber end face. This inspection method provides a contact-free approach for quantitative inspection of fiber end faces and for estimating the connection loss, and can potentially be integrated into a feedback system for automated inspection and polishing of fiber tips and fiber tip arrays.

  12. Infrared nanoantenna couplers for plasmonic slot waveguide

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Lavrinenko, Andrei

    A slot plasmonic waveguide is promising solution as a replacement of electrical interconnects in the future optical integrated circuits. In this contribution we consider a set of compact solutions for coupling the infrared light from free space to the plasmonic slot waveguide. We systematically...

  13. An Interdigitated Coupler with Defect Ground Structure

    Science.gov (United States)

    2015-07-01

    power dividing and combining, sampling, signal injection and power monitoring in microwave communication sub-systems and radar [1]. The branch-line...in the ground plane cause of the defect in the ground. This disturbance will change characteristics of a transmission line such as line capacitance ...and inductance . As high performance, compact size and low cost often meet the stringent requirements of modern microwave communication systems, new

  14. Physically correct theoretical prism waveguide coupler model.

    Science.gov (United States)

    Liu, Tao; Samuels, Robert J

    2004-07-01

    We develop new generalized four-wave-model-based waveguide mode equations for both isotropic and anisotropic systems by taking into account the influence of the incident light. These new mode equations eliminate the inherent deficiency in the conventional waveguide model, in which the action of incident light was neglected. Further, a peak-value-search (PVS) numerical method is developed to solve the four-wave-model-based mode equations. The PVS method has significant advantages in that accurate refractive index and thickness can be obtained without prior knowledge of the thickness of the air gap.

  15. Powerline Coupler for Windmill Motor/Generators

    Science.gov (United States)

    Nola, F.

    1985-01-01

    Efficiency at low windspeed increased by firing-angle control. Power coupled from wind-driven induction motor/generator to ac powerline with help from circuit. Circuit reduces power consumed by field windings thereby improving efficiency at low windspeeds. Circuit includes zerocrossing detector, ramp generator and comparator similar to those used to set firing angles for thyristors in power factor motor controllers.

  16. Design principles and realization of electro-optical circuit boards

    Science.gov (United States)

    Betschon, Felix; Lamprecht, Tobias; Halter, Markus; Beyer, Stefan; Peterson, Harry

    2013-02-01

    The manufacturing of electro-optical circuit boards (EOCB) is based to a large extent on established technologies. First products with embedded polymer waveguides are currently produced in series. The range of applications within the sensor and data communication markets is growing with the increasing maturity level. EOCBs require design flows, processes and techniques similar to existing printed circuit board (PCB) manufacturing and appropriate for optical signal transmission. A key aspect is the precise and automated assembly of active and passive optical components to the optical waveguides which has to be supported by the technology. The design flow is described after a short introduction into the build-up of EOCBs and the motivation for the usage of this technology within the different application fields. Basis for the design of EOCBs are the required optical signal transmission properties. Thereafter, the devices for the electro-optical conversion are chosen and the optical coupling approach is defined. Then, the planar optical elements (waveguides, splitters, couplers) are designed and simulated. This phase already requires co-design of the optical and electrical domain using novel design flows. The actual integration of an optical system into a PCB is shown in the last part. The optical layer is thereby laminated to the purely electrical PCB using a conventional PCB-lamination process to form the EOCB. The precise alignment of the various electrical and optical layers is thereby essential. Electrical vias are then generated, penetrating also the optical layer, to connect the individual electrical layers. Finally, the board has to be tested electrically and optically.

  17. Gravitational Lens: Deep Space Probe Design

    Science.gov (United States)

    2012-03-01

    the the presence of a hybrid coupler both TWTAs can be connected to the HGA [5]. In this configuration one TWTA will transmit right hand circular and...spacecraft and its appendages could accurately be modeled as simple three-dimensional shapes, e.g. rectangular prisms and cylinders. The second assumption

  18. Design Compass

    DEFF Research Database (Denmark)

    Stokholm, Marianne Denise J.

    2006-01-01

    is needed. This paper describes a design concept, in line with the emerging understanding and use of design, and presents a simple tool for support of design management and cooperation in interdisciplinary and intercultural teams. The tool, named “Design Compass”, describes design, not as a profession......, but as a cross field of interacting contexts and places design as both product and process in the centre. It build on a combination of ancient Greek and Roman definitions of man the made and recent models of integrated design by “state of the art” design studios like IDEO. It deals with the interaction...... of contextual based knowledge and values in the design, where integration and optimization acts as the main drive of the process. With this tools design matters can be mapped, described and communicated and knowledge shared among participants in design booth within and among companies and design teams...

  19. The mechanical design and fabrication of 162.5 MHz buncher for China accelerator driven sub-critical system injector II

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Hai Hua; Li, Youtang [Lanzhou University of Technology, Lanzhou (China); He, Yuan; Zhang, Bin; Huang, Shichun; Yuan, Chenzhang; Jia, Huan; Zhang, Shenghu [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China)

    2017-08-15

    A buncher is one of the main pieces of equipment in the medium energy beam transport line (MEBT) for China accelerator driven sub-critical system (C-ADS) Injector II. To focus the beam longitudinally and match the beam for the acceptance of the superconducting linac section, two room temperature quarter wave resonator (QWR) bunchers with frequency of 162.5 MHz have been designed as parts of the MEBT. According to the beam transmission matching of the MEBT and the geometric parameters requirements of bunchers, the unique mechanical structure and the main processing technology of buncher cavities and their couplers and tuners are described in this paper. The fabrication of bunchers and their parts have been completed and tested at high power, the test results agree well with the design requirements. These bunchers work well for about two years in Institute of Modern Physics, Chinese Academy of Sciences.

  20. The mechanical design and fabrication of 162.5 MHz buncher for China accelerator driven sub-critical system injector II

    Directory of Open Access Journals (Sweden)

    Haihua Niu

    2017-08-01

    Full Text Available A buncher is one of the main pieces of equipment in the medium energy beam transport line (MEBT for China accelerator driven sub-critical system (C-ADS Injector II. To focus the beam longitudinally and match the beam for the acceptance of the superconducting linac section, two room temperature quarter wave resonator (QWR bunchers with frequency of 162.5 MHz have been designed as parts of the MEBT. According to the beam transmission matching of the MEBT and the geometric parameters requirements of bunchers, the unique mechanical structure and the main processing technology of buncher cavities and their couplers and tuners are described in this paper. The fabrication of bunchers and their parts have been completed and tested at high power, the test results agree well with the design requirements. These bunchers work well for about two years in Institute of Modern Physics, Chinese Academy of Sciences.

  1. Design and multiphysics analysis of a 176 MHz continuous-wave radio-frequency quadrupole

    Directory of Open Access Journals (Sweden)

    S. V. Kutsaev

    2014-07-01

    Full Text Available We have developed a new design for a 176 MHz cw radio-frequency quadrupole (RFQ for the SARAF upgrade project. At this frequency, the proposed design is a conventional four-vane structure. The main design goals are to provide the highest possible shunt impedance while limiting the required rf power to about 120 kW for reliable cw operation, and the length to about 4 meters. If built as designed, the proposed RFQ will be the first four-vane cw RFQ built as a single cavity (no resonant coupling required that does not require π-mode stabilizing loops or dipole rods. For this, we rely on very detailed 3D simulations of all aspects of the structure and the level of machining precision achieved on the recently developed ATLAS upgrade RFQ. A full 3D model of the structure including vane modulation was developed. The design was optimized using electromagnetic and multiphysics simulations. Following the choice of the vane type and geometry, the vane undercuts were optimized to produce a flat field along the structure. The final design has good mode separation and should not need dipole rods if built as designed, but their effect was studied in the case of manufacturing errors. The tuners were also designed and optimized to tune the main mode without affecting the field flatness. Following the electromagnetic (EM design optimization, a multiphysics engineering analysis of the structure was performed. The multiphysics analysis is a coupled electromagnetic, thermal and mechanical analysis. The cooling channels, including their paths and sizes, were optimized based on the limiting temperature and deformation requirements. The frequency sensitivity to the RFQ body and vane cooling water temperatures was carefully studied in order to use it for frequency fine-tuning. Finally, an inductive rf power coupler design based on the ATLAS RFQ coupler was developed and simulated. The EM design optimization was performed using cst Microwave Studio and the results

  2. Engineering Design of a Multipurpose X-band Accelerating Structure

    CERN Document Server

    Gudkov, Dmitry; Samoshkin, Alexander; Zennaro, Riccardo; Dehler, Micha; Raguin, Jean-Yves

    2010-01-01

    Both FEL projects, SwissFEL and Fermi-Elettra each require an X-band RF accelerating structure for optimal bunch compression at the respective injectors. As the CLIC project is pursuing a program for producing and testing the X-band high-gradient RF structures, a collaboration between PSI, Elettra and CERN has been established to build a multipurpose X-band accelerating structure. This paper focuses on its engineering design, which is based on the disked cells jointed together by diffusion bonding. Vacuum brazing and laser beam welding is used for auxiliary components. The accelerating structure consists of two coupler subassemblies, 73 disks and includes a wakefield monitor and diagnostic waveguides. The engineering study includes the external cooling system, consisting of two parallel cooling circuits and an RF tuning system, which allows phase advance tuning of the cell by deforming the outer wall. The engineering solution for the installation and sealing of the wake field monitor feed-through devices that...

  3. Design Considerations for the LHC 200 MHz RF System

    CERN Document Server

    Boussard, Daniel; Kindermann, H P; Linnecar, Trevor Paul R; Marque, S; Tückmantel, Joachim

    2000-01-01

    The longitudinal beam transfer from the SPS into the LHC 400 MHz buckets will not be free of losses without a lower frequency capture system and a fast longitudinal damping system in LHC. We present a complete study of a combined system using four identical copper cavities at 200 MHz delivering 3 MV total CW voltage and having still enough bandwidth to achieve fast longitudinal damping. The shape of a cavity was designed according to the accelerating mode performance, its tuning and the higher order mode spectrum with respect to the LHC beam lines and their possible attenuation. The possibility to park the cavities during coast was included. The local heat load and the corresponding cooling water distribution as well as deformations were studied and techniques to build the cavity with all ports at low cost are proposed. The parameters of the RF generators, couplers and detuning are determined. Simulations of the total LHC RF system incorporating real delays, generator bandwidth and the control loops confirm t...

  4. Design Anthropology in Participatory Design

    DEFF Research Database (Denmark)

    Smith, Rachel Charlotte; Gislev Kjærsgaard, Mette

    2014-01-01

    In this workshop we explore the opportunities of ethnography and design anthropology in Participatory Design (PD) as an approach to design in an increasingly global and digital world. Traditionally, ethnography has been used in PD to research real-life contexts and challenges, and as ways...... opportunities of using design anthropology as a holistic and critical approach to societal challenges, and a way for anthropologists and designers to engage in design that extends beyond the empirical....

  5. Reparação traqueal em cães: transplante autógeno vs implante homógeno conservado em glicerina a 98% de cartilagem da pina Tracheal healing in dogs: autograft versus homograft implant preserved in 98% glycerin of pinna cartilage

    Directory of Open Access Journals (Sweden)

    Emerson Antonio Contesini

    2001-08-01

    Full Text Available Diversas patologias acometem a traquéia dos animais domésticos de forma a comprometer o fluxo respiratório, inclusive a sobrevivência do animal. Obstrução por corpo estranho ou neoplasias, rupturas traumáticas, colapso e estenose são tidas como as principais. Reparações de defeitos induzidos experimentalmente em traquéias de 12 cães foram testadas comparativamente com o emprego de retalho de cartilagem da pina autógena em 6 cães (grupo I e homógena conservada em glicerina a 98% nos demais (grupo II. Para tal, removeu-se um terço da circunferência de três anéis da traquéia cervical. Esses animais permaneceram durante um período de 30 e 45 dias sob observação e avaliação clínica em descanso e exercício físico moderado, sem apresentar quaisquer complicações decorrentes da cirurgia. Ao final desse período, o segmento traqueal operado foi submetido à avaliação macro e microscópica, sendo observado macroscopicamente, encobrimento completo do retalho por uma estrutura delgada e esbranquiçada em todos os animais. A análise microscópica da região transplantada do grupo I revelou que a mesma foi invadida por tecido de granulação, a lâmina própria apresentou moderada infiltração de neutrófilos e pouca fibrose com focos de hiperplasia epitelial. Nos animais do grupo II, foram observadas, na região do implante, além disso, discreta invasão de macrófagos e vasos neoformados, com inflamação moderada na lâmina própria, e epitélio sem alteração. Essas observações sugerem que o implante de cartilagem da pina conservada em glicerina a 98%, induz resposta menos agressiva pelo leito receptor, embora isso não seja evidenciado macroscopicamente.Several patologies affect the trachea, compromising the respiratory stream and the animal survival. Foreign bodies, neoplasm, ruptures, collapse and stricture are the most common ones. The effects of canine pinna cartilage implantation were evaluated in 12 dogs. Six of

  6. Matriz óssea homóloga desmineralizada associada à medula óssea autógena fresca na artrodese vertebral dorsolateral lombar em coelhos Homologous demineralized bone matrix associated to autologous bone marrow in a rabbit dorsolateral lumbar vertebral fusion

    Directory of Open Access Journals (Sweden)

    D. Rizzo

    2005-04-01

    Full Text Available Foi avaliada a matriz óssea homóloga desmineralizada (MOD, associada à medula óssea autógena fresca (MO, na artrodese vertebral dorsolateral lombar em 24 coelhos (grupo 1, depositada sobre os processos transversos de L5-L6 previamente descorticados. Em outros nove coelhos (grupo-controle, foi realizada apenas a descorticação dos processos transversos e nas diferentes avaliações, foi observada insignificante reação periosteal local, sem união óssea. No grupo 1, às cinco semanas de pós-operatório, 87,5% dos animais apresentaram união (artrodese à palpação, seguido por 75 e 100% às sete e nove semanas, respectivamente. Os índices de artrodese aos RX foram de 50%, 62% e 75%, no mesmo período de avaliação. Histologicamente, às cinco semanas havia características de osteointegração da MOD com os processos transversos descorticados, de onde partiram os vasos sangüíneos que penetraram a matriz, e presença de ilhas de cartilagem no centro do enxerto. Nas semanas seguintes, a ossificação endocondral evoluiu e a MOD foi quase totalmente substituída por tecido ósseo trabecular, formando uma ponte de osso maduro entre e sobre os processos transversos adjacentes, propiciando ao segmento operado maior resistência mecânica em comparação aos segmentos adjacentes. A associação da MOD com a MO mostrou-se uma opção exeqüível e de baixo custo na artrodese vertebral dorsolateral lombar em coelhos.It was evaluated the homologous demineralized bone matrix (HDBM, associated with the fresh autogenous bone marrow (FABM, in the vertebral dorsolateral lumbar union in 24 rabbits (group 1, that was placed on the transverse processes of previously decorticated L5-L6 vertebrae. In other nine rabbits (control group, it was just accomplished the decortications of the transverse processes, which showed insignificant local periostial reaction, without bone union after different evaluations. In the group 1, after five weeks of

  7. Research Design

    DEFF Research Database (Denmark)

    2019-01-01

    Gunnar Scott Reinbacher (editor) Antology.  Research Design : Validation in Social Sciences. Gunnar Scott Reinbacher: Introduction. Research design and validity. 15p Ole Riis: Creative Research design. 16 p Lennart Nørreklit: Validity in Research Design. 24p Gitte Sommer Harrits: Praxeological kn...

  8. Evidensbaseret design

    DEFF Research Database (Denmark)

    Pagh, Jesper

    2013-01-01

    Debatindlæg om evidensbaseret design, som argumenterer for at det dels er en gammeldags, modernistisk tilgang til design, dels ikke baserer sig på evidens.......Debatindlæg om evidensbaseret design, som argumenterer for at det dels er en gammeldags, modernistisk tilgang til design, dels ikke baserer sig på evidens....

  9. Design Games

    DEFF Research Database (Denmark)

    Johansson, Martin Wetterstrand

    2007-01-01

    In this paper design games are discussed as an approach to managing design sessions. The focus is on the collaborative design session and more particular on how to set up the collaboration and reinsure progress. Design games have the advantage of framing the collaborative assignment at hand....... Experiments can be set up to explore possible futures and design games has the qualities of elegantly focus the work at the same time as it lessens the burden for the process facilitator. The present paper goes into detail about how design games can be set up to facilitate collaboration and how the design...

  10. FPGA design

    CERN Document Server

    Simpson, Philip

    2010-01-01

    This book describes best practices for successful FPGA design. It is the result of the author's meetings with hundreds of customers on the challenges facing each of their FPGA design teams. By gaining an understanding into their design environments, processes, what works and what does not work, key areas of concern in implementing system designs have been identified and a recommended design methodology to overcome these challenges has been developed. This book's content has a strong focus on design teams that are spread across sites. The goal being to increase the productivity of FPGA design t

  11. VLSI design

    CERN Document Server

    Basu, D K

    2014-01-01

    Very Large Scale Integrated Circuits (VLSI) design has moved from costly curiosity to an everyday necessity, especially with the proliferated applications of embedded computing devices in communications, entertainment and household gadgets. As a result, more and more knowledge on various aspects of VLSI design technologies is becoming a necessity for the engineering/technology students of various disciplines. With this goal in mind the course material of this book has been designed to cover the various fundamental aspects of VLSI design, like Categorization and comparison between various technologies used for VLSI design Basic fabrication processes involved in VLSI design Design of MOS, CMOS and Bi CMOS circuits used in VLSI Structured design of VLSI Introduction to VHDL for VLSI design Automated design for placement and routing of VLSI systems VLSI testing and testability The various topics of the book have been discussed lucidly with analysis, when required, examples, figures and adequate analytical and the...

  12. Team designing

    DEFF Research Database (Denmark)

    Denise J. Stokholm, Marianne

    2012-01-01

    Future wellbeing is depending on human competences in order to strengthen a sustainable development. This requires system thinking and ability to deal with complexity, dynamic and a vast of information. `We need to move away from present principles of breaking down problems into components and give...... and intercultural teams in design and the understanding of design as a process of transformation and information management call for a model with capacity to facilitate both `the what` and `the how` This paper will describe a systemic model of design based on a holistic approach to design developed by the author...... in relation to a design-engineering education at Aalborg University. It will exemplify how the model has been used in workshops on team designing, challenged design learning and affected design competence. In specific it will investigate the influence of visual models of the perception of design, design...

  13. Design Drawing

    DEFF Research Database (Denmark)

    Steinø, Nicolai

    2018-01-01

    In a time of computer aided design, computer graphics and parametric design tools, the art of design drawing is in a state of neglect. But design and drawing are inseparably linked in ways which often go unnoticed. Essentially, it is very difficult, if not impossible, to conceive of designs without...... and better than most medium-skilled draftsmen, drawing in design is not only about representing final designs. In fact, several steps involving the capacity to draw lie before the representation of a final design. Not only is drawing skills a prerequisite for learning about the nature of existing objects...... and thus to build a vocabulary of design. It is also a prerequisite for both reflecting and communicating about design ideas. In this paper, a taxonomy of notation, reflection, communication and presentation drawing is presented, discussed and exemplified. The paper is theoretical in nature, discussing...

  14. Design Accountability

    DEFF Research Database (Denmark)

    Koskinen, Ilpo; Krogh, Peter

    2015-01-01

    When design research builds on design practice, it may contribute to both theory and practice of design in ways richer than research that treats design as a topic. Such research, however, faces several tensions that it has to negotiate successfully in order not to lose its character as research....... This paper looks at constructive design research which takes the entanglement of theory and practice as its hallmark, and uses it as a test case in exploring how design researchers can work with theory, methodology, and practice without losing their identity as design researchers. The crux of practice based...... design research is that where classical research is interested in singling out a particular aspect and exploring it in depth, design practice is characterized by balancing numerous concerns in a heterogenous and occasionally paradoxical product. It is on this basis the notion of design accountability...

  15. Mechanical design

    CERN Document Server

    Risitano, Antonino

    2011-01-01

    METHODOLOGICAL STATEMENT OF ENGINEERING DESIGNApproaches to product design and developmentMechanical design and environmental requirementsPROPERTIES OF ENGINEERING MATERIALSMaterials for mechanical designCharacterization of metalsStress conditionsFatigue of materialsOptimum material selection in mechanical designDESIGN OF MECHANICAL COMPONENTS AND SYSTEMSFailure theoriesHertz theoryLubrificationShafts and bearingsSplines and keysSpringsFlexible machine elementsSpur gearsPress and shrink fitsPressure tubesCouplingsClutchesBrakes

  16. Thermo mechanical design of normal-conducting deflecting cavities at the Advanced Photon Source for short x-ray pulse generation.

    Energy Technology Data Exchange (ETDEWEB)

    Brajuskovic, B.; Collins, J.; Den Hartog, P.; Morrison, L.; Waldschmidt, G.

    2008-01-01

    A normal-conducting deflecting cavity is being designed at the Advanced Photon Source (APS) as a part of the short x-ray pulse project intended to provide users with approximately 2 picosecond x-rays. The system will use two pairs of 3-cell cavities in sectors 6ID and 7ID for the generation of the x-ray pulse in the 7ID beamline. The 3-cell cavities are designed to provide the desired beam deflection while absorbing in excess of 4 kW of power from a pulsed rf system and up to 2.6 kW in the damper system of high-order mode (HOM) and low-order mode (LOM) waveguides. Since the cavity frequency is very sensitive to thermal expansion, the cooling water system is designed so that it is able to control cavity temperature to within 0.1 C. This paper describes the optimization of the thermomechanical design of the cavity based on calculation of thermal stresses and displacement caused by the generated heat loads, and presents the design of a cooling water system required for the proper operation of the cavities.

  17. Memory design

    DEFF Research Database (Denmark)

    Tanderup, Sisse

    Mind and Matter - Nordik 2009 Conference for Art Historians Design Matters Contributed Memory design BACKGROUND My research concerns the use of memory categories in the designs by the companies Alessi and Georg Jensen. When Alessi's designers create their products, they are usually inspired...... by cultural forms, often specifically by the concept of memory in philosophy, sociology and psychology, while Danish design traditionally has been focusing on form and function with frequent references to the forms of nature. Alessi's motivation for investigating the concept of memory is that it adds...... a cultural dimension to the design objects, enabling the objects to make an identity-forming impact. Whether or not the concept of memory plays a significant role in Danish design has not yet been elucidated fully. TERMINOLOGY The concept of "memory design" refers to the idea that design carries...

  18. Design Dancing

    DEFF Research Database (Denmark)

    Denise J. Stokholm, Marianne

    2013-01-01

    In Creative cooperation and co-creation is often obstructed by different perception of design and innovation, inexperience in design and the lack of a common ground for dynamic interaction and tangible tools to support the creative process. This is a problem because it leads to miscommunication...... and lower the benefits of team design as a matter of integration and transformation which benefit from a diversity of input through interdisciplinary design. This paper describes a design style approach to research as a continuous process of trial and error with the idea of creating and demonstrating...... a generic design tool for facilitation of co-creation. At visual model of design as a system in the form of a structured framework including all parameters in design has shown to poses use capacity to support co-creation in teams of participants inexperienced in design. The research is dealing...

  19. Designing pathways

    DEFF Research Database (Denmark)

    2010-01-01

    The theoretical background in this chapter is organizational studies and especially theories about design and design processes in organizations. The concept of design is defined as a particular kind of work aimed at making arrangements in order to change existing situations into desired ones....... The illustrative case example is the introduction of clinical pathways in a psychiatric department. The contribution to a general core of design research is the development of the concept of design work and a critical discussion of the role of technological rules in design work....

  20. Designing Interfaces

    CERN Document Server

    Tidwell, Jenifer

    2010-01-01

    Despite all of the UI toolkits available today, it's still not easy to design good application interfaces. This bestselling book is one of the few reliable sources to help you navigate through the maze of design options. By capturing UI best practices and reusable ideas as design patterns, Designing Interfaces provides solutions to common design problems that you can tailor to the situation at hand. This updated edition includes patterns for mobile apps and social media, as well as web applications and desktop software. Each pattern contains full-color examples and practical design advice th