Designing Interaction Paradigms for Web-Information Search and Retrieval

As the complexity of the information available on the web increases, the role of user-data interaction paradigms is becoming increasingly critical for the success of web information retrieval. Recent years have witnessed significant advances in techniques for indexing and querying web data. However, in the same period, limited advancements have been made in developing paradigms and researching algorithmic issues associated with the design of interfaces for web-search. In this paper, we propose a novel paradigm for enabling multiple-perspective query and interaction in web search. Underlying the proposed metaphor are information and pattern analysis techniques that help determine semantic correlations between web pages, identify and extract information critical for intuitive understanding and hypothesis generation, and support effective and multiple-perspective interactions between users and the data. We provide a comprehensive study on the effectiveness and efficiency of the proposed approach in query-retrieval scenarios involving complex information goals. Our investigations point to the importance of developing novel ways to mediate interactions during web-search and will be useful in the development of the next generation of real-world solutions for web information retrieval

Non-commutative field theory approach to two-dimensional vortex liquid system

We investigate the non-commutative (NC) field theory approach to the vortex liquid system restricted to the lowest Landau level (LLL) approximation. NC field theory effectively takes care of the phase space reduction of the LLL physics in a $\star$-product form and introduces a new gauge invariant form of a quartic potential of the order parameter in the Ginzburg-Landau (GL) free energy. This new quartic interaction coupling term has a non-trivial equivalence relation with that obtained by Br\'ezin, Nelson and Thiaville in the usual GL framework. The consequence of the equivalence is discussed.Comment: Add vortex lattice formation, more references, and one autho

Tin‐Containing Graphite for Sodium‐Ion Batteries and Hybrid Capacitors

The limited Na-storage capacity of graphite anodes for sodium-ion batteries (∼110 mAh g−1) is significantly enhanced by the incorporation of nanosized Sn (17 wt%). The composite (SntGraphite), prepared by simple annealing of graphite with SnCl2, shows a specific capacity of 223 mAh g−1 (at 50 mA g−1) combined with excellent cycle life (i. e., 96 % of capacity retention after 2,200 cycles at 1 A g−1) and initial Coulomb efficiency (90 %). The combined storage of sodium in graphite (by solvent co-intercalation) and Sn (by alloy formation) is followed by in situ X-ray diffraction and in situ electrochemical dilatometry (ECD). While the additional tin almost doubles the electrode capacity, its contribution to the electrode expansion (∼3 %) is surprisingly small. The use of SntGraphite as anode for sodium-ion hybrid capacitors with activated carbon as cathode provides a maximum energy and power density of ∼93 Wh kg−1 and 7.8 kW kg−1, with a capacity retention of ∼80 % after 8,000 cycles.Peer Reviewe

Tin-Containing Graphite for Sodium-Ion Batteries and Hybrid Capacitors

The limited Na-storage capacity of graphite anodes for sodium-ion batteries (∼110 mAh g−1) is significantly enhanced by the incorporation of nanosized Sn (17 wt%). The composite (SntGraphite), prepared by simple annealing of graphite with SnCl2, shows a specific capacity of 223 mAh g−1 (at 50 mA g−1) combined with excellent cycle life (i. e., 96 % of capacity retention after 2,200 cycles at 1 A g−1) and initial Coulomb efficiency (90 %). The combined storage of sodium in graphite (by solvent co-intercalation) and Sn (by alloy formation) is followed by in situ X-ray diffraction and in situ electrochemical dilatometry (ECD). While the additional tin almost doubles the electrode capacity, its contribution to the electrode expansion (∼3 %) is surprisingly small. The use of SntGraphite as anode for sodium-ion hybrid capacitors with activated carbon as cathode provides a maximum energy and power density of ∼93 Wh kg−1 and 7.8 kW kg−1, with a capacity retention of ∼80 % after 8,000 cycles.Peer Reviewe

Fabrication and current-voltage characterization of a ferroelectric lead zirconate titanate/AlGaN∕GaN field effect transistor

We demonstrated ferroelectricfield effect transistors (FFETs) with hysteretic I-V characteristics in a modulation-doped field effect transistors(MODFET)AlGaN∕GaN platform with ferroelectricPb(Zr,Ti)O3 between a GaN channel and a gate metal. The pinch-off voltage was about 6–7V comparable to that of conventional Schottky gate MODFET. Counterclockwise hysteresis appeared in the transfer characteristics with a drain current shift of ∼5mA for zero gate-to-source voltage. This direction is opposite and much more pronounced than the defect induced clockwise hysteresis in conventional devices, which suggests that the key factor contributing to the counterclockwise hysteresis of the FFET is the ferroelectric switching effect of the lead zirconate titanate gate

Mode-Locking in Quantum-Hall-Effect Point Contacts

We study the effect of an ac drive on the current-voltage (I-V) characteristics of a tunnel junction between two fractional Quantum Hall fluids at filling $\nu ^{-1}$ an odd integer. Within the chiral Luttinger liquid model of edge states, the point contact dynamics is described by a driven damped quantum mechanical pendulum. In a semi-classical limit which ignores electron tunnelling, this model exhibits mode-locking, which corresponds to current plateaus in the I-V curve at integer multiples of $I= e\omega /2\pi$, with $\omega$ the ac drive angular frequency. By analyzing the full quantum model at non-zero $\nu$ using perturbative and exact methods, we study the effect of quantum fluctuation on the mode-locked plateaus. For $\nu=1$ quantum fluctuations smear completely the plateaus, leaving no trace of the ac drive. For $\nu \ge 1/2$ smeared plateaus remain in the I-V curve, but are not centered at the currents $I=n e \omega /2\pi$. For $\nu < 1/2$ rounded plateaus centered around the quantized current values are found. The possibility of using mode locking in FQHE point contacts as a current-to-frequency standard is discussed.Comment: 12 pages, 8 figures, minor change

Plasmon Modes and Correlation Functions in Quantum Wires and Hall Bars

We present microscopic derivations of the one-dimensional low-energy boson effective Hamiltonians of quantum wire and quantum Hall bar systems. The quantum Hall system is distinguished by its spatial separation of oppositely directed electrons. We discuss qualitative differences in the plasmon collective mode dispersions and the ground state correlation functions of the two systems which are consequences of this difference. The slowly-decaying quasi-solid correlations expected in a quantum wire are strongly suppressed in quantum Hall bar systems.Comment: 7 pages, RevTex, 3 figures and 1 table included; references updated and minor typos correcte

The First Very Long Baseline Interferometry Image of 44 GHz Methanol Maser with the KVN and VERA Array (KaVA)

We have carried out the first very long baseline interferometry (VLBI) imaging of 44 GHz class I methanol maser (7_{0}-6_{1}A^{+}) associated with a millimeter core MM2 in a massive star-forming region IRAS 18151-1208 with KaVA (KVN and VERA Array), which is a newly combined array of KVN (Korean VLBI Network) and VERA (VLBI Exploration of Radio Astrometry). We have succeeded in imaging compact maser features with a synthesized beam size of 2.7 milliarcseconds x 1.5 milliarcseconds (mas). These features are detected at a limited number of baselines within the length of shorter than approximately 650 km corresponding to 100 Mlambda in the uv-coverage. The central velocity and the velocity width of the 44 GHz methanol maser are consistent with those of the quiescent gas rather than the outflow traced by the SiO thermal line. The minimum component size among the maser features is ~ 5 mas x 2 mas, which corresponds to the linear size of ~ 15 AU x 6 AU assuming a distance of 3 kpc. The brightness temperatures of these features range from ~ 3.5 x 10^{8} to 1.0 x 10^{10} K, which are higher than estimated lower limit from a previous Very Large Array observation with the highest spatial resolution of ~ 50 mas. The 44 GHz class I methanol maser in IRAS 18151-1208 is found to be associated with the MM2 core, which is thought to be less evolved than another millimeter core MM1 associated with the 6.7 GHz class II methanol maser.Comment: 19 pages, 3 figure

Scattering Theory of Photon-Assisted Electron Transport

The scattering matrix approach to phase-coherent transport is generalized to nonlinear ac-transport. In photon-assisted electron transport it is often only the dc-component of the current that is of experimental interest. But ac-currents at all frequencies exist independently of whether they are measured or not. We present a theory of photon-assisted electron transport which is charge and current conserving for all Fourier components of the current. We find that the photo-current can be considered as an up- and down-conversion of the harmonic potentials associated with the displacement currents. As an example explicit calculations are presented for a resonant double barrier coupled to two reservoirs and capacitively coupled to a gate. Two experimental situations are considered: in the first case the ac-field is applied via a gate, and in the second case one of the contact potentials is modulated. For the first case we show that the relative weight of the conduction sidebands varies with the screening properties of the system. In contrast to the non-interacting case the relative weights are not determined by Bessel functions. Moreover, interactions can give rise to an asymmetry between absorption and emission peaks. In the contact driven case, the theory predicts a zero-bias current proportional to the asymmetry of the double barrier. This is in contrast to the discussion of Tien and Gordon which, in violation of basic symmetry principles, predicts a zero-bias current also for a symmetric double barrier.Comment: 15 pages, 6 figures, REVTE