2,208 research outputs found
Incorporating Statistical Information of Lexical Dependency into a Rule-Based Parser
PACLIC 23 / City University of Hong Kong / 3-5 December 200
Synthesis and Activity of Six-Membered Cyclic Alkyl Amino CarbeneâRuthenium Olefin Metathesis Catalysts
Ruâcyclic alkyl amino carbene (RuâCAAC) olefin metathesis catalysts perform extraordinarily in metathesis macrocyclization and ethenolysis, but previous studies have been limited to the use of five-membered CAAC (CAAC-5) ligands. In this work, we synthesized a different group of ruthenium catalysts with more Ï-donating and Ï-accepting six-membered CAAC (CAAC-6) ligands, and their metathesis activity was probed through initiation studies, ring-closing metathesis (RCM), cross-metathesis, and ethenolysis. These catalysts display higher initiation rates than analogous RuâCAAC-5 complexes but demonstrate lower activity in RCM and ethenolysis
Dirac Bilayer Metasurfaces as an Inverse Gires-Tournois Etalon
Efficient transmissive pure-phase resonances are highly desirable for optical
modulation and wavefront engineering. Here, we propose a novel principle to
realize a pure-phase resonance in an extremely broad transmission band, as
opposed to previous approaches restricted to operating in reflection mode or
over a narrow spectral band. We show that a glide-symmetric bilayer metasurface
mathematically mimicking a two-dimensional Dirac semimetal induces
unidirectional guided-mode excitation and perfect leakage-radiation blazing at
the transmission channel. These effects create a peculiar resonant-scattering
configuration, similar to the classical reflective Gires-Tournois etalon, but
in transmission, providing full 2pi phase modulation with constant
transmittance near 100%. Most importantly, this effect persists over an
extremely wide band, associated with topological effects. Hence, our proposed
approach produces a spectrally and parametrically robust pure-phase resonance
effect in transmission, which is highly beneficial for practical applications.Comment: 11 pages, 5 figure
How to Overcome the Domain Barriers in Pattern-Based Machine Translation System
PACLIC / The University of the Philippines Visayas Cebu College Cebu City, Philippines / November 20-22, 200
Customizing an English-Korean Machine Translation System for Patent/Technical Documents Translation
PACLIC 23 / City University of Hong Kong / 3-5 December 200
Recognizing Coordinate Structures for Machine Translation of English Patent Documents
PACLIC / The University of the Philippines Visayas Cebu College Cebu City, Philippines / November 20-22, 200
Experimental Investigation for Tensile Performance of GFRP-Steel Hybridized Rebar
Tensile performance of the recently developed âFRP Hybrid Barâ at Korea Institute of Civil Engineering and Building Technology (KICT) is experimentally evaluated by the authors. FRP Hybrid Bar is introduced to overcome the low elastic modulus of the existing GFRP bars to be used as a structural member in reinforced concrete structures. The concept of material hybridization is applied to increase elastic modulus of GFRP bars by using steel. This hybridized GFRP bar can be used in concrete structures as a flexural reinforcement with a sufficient level of elastic modulus. In order to verify the effect of material hybridization on tensile properties, tensile tests are conducted. The test results for both FRP Hybrid Bar and the existing GFRP bars are compared. The results indicate that the elastic modulus of FRP Hybrid Bar can be enhanced by up to approximately 250 percent by the material hybridization with a sufficient tensile strength. To ensure the long-term durability of FRP Hybrid Bar to corrosion resistance, the individual and combined effects of environmental conditions on FRP Hybrid Bar itself as well as on the interface between rebar and concrete are currently under investigation
Topological beaming of light
Nanophotonic light emitters are key components in numerous application areas because of their compactness and versatility. Here, we propose a topological beam emitter structure that takes advantage of submicrometer footprint size, small divergence angle, high efficiency, and adaptable beam shaping capability. The proposed structure consists of a topological junction of two guided-mode resonance gratings inducing a leaky Jackiw-Rebbi state resonance. The leaky Jackiw-Rebbi state leads to in-plane optical confinement with funnel-like energy flow and enhanced emission probability, resulting in highly efficient optical beam emission. In addition, the structure allows adaptable beam shaping for any desired positive definite profiles by means of Dirac mass distribution control, which can be directly encoded in lattice geometry parameters. Therefore, the proposed approach provides highly desirable properties for efficient microâlight emitters and detectors in various applications including display, solid-state light detection and ranging, laser machining, label-free sensors, optical interconnects, and telecommunications
Effects of paramagnetic fluctuations on the thermochemistry of MnO (100) surfaces in the oxygen evolution reaction
We investigated the effects of paramagnetic (PM) fluctuations on the
thermochemistry of the MnO(100) surface in the oxygen evolution reaction (OER)
using the "noncollinear magnetic sampling method \textit{plus} "
(NCMSM). Various physical properties, such as the electronic structure,
free energy, and charge occupation, of the MnO (100) surface in the PM state
with several OER intermediates, were reckoned and compared to those in the
antiferromagnetic (AFM) state. We found that PM fluctuation enhances charge
transfer from a surface Mn ion to each of the intermediates and strengthens the
chemical bond between them, while not altering the overall features, such as
the rate determining step and resting state, in reaction pathways. The enhanced
charge transfer can be attributed to the delocalized nature of valence bands
observed in the PM surface. In addition, it was observed that chemical-bond
enhancement depends on the intermediates, resulting in significant deviations
in reaction energy barriers. Our study suggests that PM fluctuations play a
significant role in the thermochemistry of chemical reactions occurring on
correlated oxide surfaces.Comment: Maintext: 15 pages, 3 figures 2 tables; SI: 3 pages, 2 figure
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