5,165 research outputs found

    LHC top mass: alternative methods and prospects for the future

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    Future lepton colliders will have a rich top quark physics program which would add to our understanding of this interesting quark and promise an ultimate precision on the experimental knowledge of top-quark mass. We present possible improvements in the understanding of systematic uncertainties for various top-quark mass measurement techniques at the LHC, including projections for running conditions foreseen in the future.Comment: Talk presented at the International Workshop on Future Linear Colliders (LCWS13), Tokyo, Japan, 11-15 November 201

    Theoretical Investigation of Intersections of Metal-Insulator-Silicon-Insulator-Metal Waveguides

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    We theoretically investigate simple, circle-shaped, and diamond-shaped intersections of metal-insulator-silicon-insulator-metal (MISIM) waveguides. Because of the strong light confinement of the hybrid plasmonic waveguides, the simple intersection does not work efficiently. The low efficiency of the simple intersection is improved in the other intersections, and the diamond-shaped intersection is superior to the circle-shaped one. When the footprint of the diamond-shaped intersection is just 1.96 ??m2, its throughput is between -0.68 and -0.78 dB in the wavelength interval between 1.45 and 1.60 ?? m, and its crosstalk is smaller than -18 dB in the interval. This compact, efficient intersection may pave the way to on-chip hybrid networks of photonic and plasmonic devices.ope

    Dynamic simulation of polyester mooring lines

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    A numerical scheme, known as CABLE3D, originally developed for the simulation of dynamics of steel chain-wire mooring lines is extended to allow for the large elongation in a mooring line, the dependence of the modulus on tension, and energy dissipation of a polyester rope under mean and cyclic loads. The modified CABLE3D is then integrated into a numerical package, known as COUPLE6D, for computing the interaction between a floating structure and its hybrid polyester mooring system. The Deepstar Spar is chosen in this study to represent the floating structure. By considering large elongation in polyester ropes in numerical simulation, the static offset curve of a polyester mooring system is softer than that calculated under the assumption of small elongation. That is, about 10% reduction in restoring force at the mean offset position of the Spar under the impact of 100-year hurricane storm. The effects of the mean loads on the modulus of polyester ropes are much greater than those of the dynamic loads. Hence, the former is more important in the simulation of the response of floating structures. The energy dissipation in polyester ropes under cyclic loading does not play significant roles in the responses of the Spar and tensions in a polyester mooring system. The above findings, although observed based on the numerical simulation of a particular floating structure, namely Spar, may have implications to other floating offshore structures moored by a polyester mooring system. Two systems are simulated in two different met-ocean conditions: hurricane and loop current condition. To study the properties of polyester, numerical simulation were conducted in three ways. Those are related to the modulus based on mean load, mean and dynamic loads, and structural damping respectively. Through the simulation, statistics of motions of the hull and tension in the mooring lines are compared with those of a conventional steel mooring system

    Scour depth around multiple piles for current and wave

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    Experiments on scour around multiple piles were carried out for several current and wave conditions: pile numbers were 1, 3, and 7; and wave only, current only, and current and wave flows. A moderate wave condition was chosen as the representative wave, which produced relatively small scour depth. A depth-average current speed was chosen as the representative current, which produced relatively large scour hole. When waves were superimposed on current, scour hole depth decreased. Existing the Sumer and Fredsøe’s prediction formula of scour hole depth for current and wave flows for multiple piles describes the present experimental results reasonably well

    Integrated 3D glass modules with high-Q inductors and thermal dissipation for RF front-end applications

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    The objectives of this research are to model, design, fabricate and validate high quality factor (Q > 100 at 2.4 GHz for 3-10 nH/mm2) inductors and innovative thermal structures with copper through-package vias to maintain low junction temperatures of < 85 oC in power amplifiers, and demonstrate ultra-thin fully-integrated dual-band (2.4 GHz/ 5GHz) WLAN modules with passive-active integration on ultra-thin glass substrates with double-side RF circuits and copper through-package vias (TPVs). Today’s RF subsystems are 2D single or multichip packages made of either organic laminates or LTCC (low temperature co-fired ceramic) substrates. The need for form-factor reduction in RF subsystems in both z and x-y direction has led to the evolution of embedded die-package architectures in thin laminates with dies facing up or down. This also reduces insertion loss and improves signal integrity by minimizing electromagnetic interference (EMI), package parasitics and routing issues. For further improvement in performance and miniaturization, glass is proposed as an ideal substrate for RF module integration. However, major design and fabrication challenges need to be addressed to achieve ultra-thin high Q RF components and also enable IC cooling to eliminate hotspots on glass substrates, which forms the key focus of this thesis.Ph.D