30,289 research outputs found

    Do Stronger Intellectual Property Rights Protection Induce More Bilateral Trade? Evidence from China's Imports

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    Most of the previous studies on the effect of IPR protection on international trade have been from the perspective of major industrialized nations. However, much of the current debate on the effects of IPR protection involves large developing countries with high threat of imitation. This study contributes to the literature by analyzing the impact of the strengthening of patent laws in China on its bilateral trade flows. We estimate the effects of patent rights protection on China’s imports at the aggregate and detailed product categories for both OECD (developed) and non-OECD (developing) countries. The empirical results suggest that increased patent rights protection stimulate China’s imports, particularly in the knowledge-intensive product categories. Furthermore, while the evidence in support of the market expansion effect is significant for imports from OECD countries, it is rather weak and mostly insignificant for imports from non-OECD countries.Intellectual property rights, patent laws, international trade, International Relations/Trade, F13, 034,

    Generalized Area Spectral Efficiency: An Effective Performance Metric for Green Wireless Communications

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    Area spectral efficiency (ASE) was introduced as a metric to quantify the spectral utilization efficiency of cellular systems. Unlike other performance metrics, ASE takes into account the spatial property of cellular systems. In this paper, we generalize the concept of ASE to study arbitrary wireless transmissions. Specifically, we introduce the notion of affected area to characterize the spatial property of arbitrary wireless transmissions. Based on the definition of affected area, we define the performance metric, generalized area spectral efficiency (GASE), to quantify the spatial spectral utilization efficiency as well as the greenness of wireless transmissions. After illustrating its evaluation for point-to-point transmission, we analyze the GASE performance of several different transmission scenarios, including dual-hop relay transmission, three-node cooperative relay transmission and underlay cognitive radio transmission. We derive closed-form expressions for the GASE metric of each transmission scenario under Rayleigh fading environment whenever possible. Through mathematical analysis and numerical examples, we show that the GASE metric provides a new perspective on the design and optimization of wireless transmissions, especially on the transmitting power selection. We also show that introducing relay nodes can greatly improve the spatial utilization efficiency of wireless systems. We illustrate that the GASE metric can help optimize the deployment of underlay cognitive radio systems.Comment: 11 pages, 8 figures, accepted by TCo

    Computer-aided modeling and prediction of performance of the modified Lundell class of alternators in space station solar dynamic power systems

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    The main purpose of this project is the development of computer-aided models for purposes of studying the effects of various design changes on the parameters and performance characteristics of the modified Lundell class of alternators (MLA) as components of a solar dynamic power system supplying electric energy needs in the forthcoming space station. Key to this modeling effort is the computation of magnetic field distribution in MLAs. Since the nature of the magnetic field is three-dimensional, the first step in the investigation was to apply the finite element method to discretize volume, using the tetrahedron as the basic 3-D element. Details of the stator 3-D finite element grid are given. A preliminary look at the early stage of a 3-D rotor grid is presented

    Isostaticity and the solidification of semiflexible polymer melts

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    Using molecular dynamics simulations of a tangent-soft-sphere bead-spring polymer model, we examine the degree to which semiflexible polymer melts solidify at isostaticity. Flexible and stiff chains crystallize when they are isostatic as defined by appropriate degree-of-freedom-counting arguments. Semiflexible chains also solidify when isostatic if a generalized isostaticity criterion that accounts for the slow freezing out of configurational freedom as chain stiffness increases is employed. The dependence of the average coordination number at solidification Z(Ts)Z(T_s) on chains' characteristic ratio CC_\infty has the same functional form [Zabln(C)Z \simeq a - b\ln(C_\infty)] as the dependence of the average coordination number at jamming Z(ϕJ)Z(\phi_J) on CC_\infty in athermal systems, suggesting that jamming-related phenomena play a significant role in thermal polymer solidification

    Phase cascade bridge rectifier array in a 2-D lattice

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    We report on a novel rectification phenomenon in a 2-D lattice network consisting of N×N sites with diode and AC source elements with controllable phases. A phase cascade configuration is described in which the current ripple in a load resistor goes to zero in the large N limit, enhancing the rectification efficiency without requiring any external capacitor or inductor based filters. The integrated modular configuration is qualitatively different from conventional rectenna arrays in which the source, rectifier and filter systems are physically disjoint. Exact analytical results derived using idealized diodes are compared to a realistic simulation of commercially available diodes. Our results on nonlinear networks of source-rectifier arrays are potentially of interest to a fast evolving field of distributed power networks

    The Friedberg-Lee model at finite temperature and density

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    The Friedberg-Lee model is studied at finite temperature and density. By using the finite temperature field theory, the effective potential of the Friedberg-Lee model and the bag constant B(T)B(T) and B(T,μ)B(T,\mu) have been calculated at different temperatures and densities. It is shown that there is a critical temperature TC106.6MeVT_{C}\simeq 106.6 \mathrm{MeV} when μ=0MeV\mu=0 \mathrm{MeV} and a critical chemical potential μ223.1MeV\mu \simeq 223.1 \mathrm{MeV} for fixing the temperature at T=50MeVT=50 \mathrm{MeV}. We also calculate the soliton solutions of the Friedberg-Lee model at finite temperature and density. It turns out that when TTCT\leq T_{C} (or μμC\mu \leq \mu_C), there is a bag constant B(T)B(T) (or B(T,μ)B(T,\mu)) and the soliton solutions are stable. However, when T>TCT>T_{C} (or μ>μC\mu>\mu_C) the bag constant B(T)=0MeVB(T)=0 \mathrm{MeV} (or B(T,μ)=0MeVB(T,\mu)=0 \mathrm{MeV}) and there is no soliton solution anymore, therefore, the confinement of quarks disappears quickly.Comment: 12 pages, 11 figures; version accepted for publication in Phys. Rev.

    Chest pain in a Basketball Player

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    Please view the clinical abstract in the attached PDF fil

    Extended dual description of Mott transition beyond two-dimensional space

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    Motivated by recent work of Mross and Senthil [Phys. Rev. B \textbf{84}, 165126 (2011)] which provides a dual description for Mott transition from Fermi liquid to quantum spin liquid in two space dimensions, we extend their approach to higher dimensional cases, and we provide explicit formalism in three space dimensions. Instead of the vortices driving conventional Fermi liquid into quantum spin liquid states in 2D, it is the vortex lines to lead to the instability of Fermi liquid in 3D. The extended formalism can result in rich consequences when the vortex lines condense in different degrees of freedom. For example, when the vortex lines condense in charge phase degrees of freedom, the resulting effective fermionic action is found to be equivalent to that obtained by well-studied slave-particle approaches for Hubbard and/or Anderson lattice models, which confirm the validity of the extended dual formalism in 3D. When the vortex lines condense in spin phase degrees of freedom, a doublon metal with a spin gap and an instability to the unconventional superconducting pairing can be obtained. In addition, when the vortex lines condense in both phase degrees, an exotic doubled U(1) gauge theory occurs which describes a separation of spin-opposite fermionic excitations. It is noted that the first two features have been discussed in a similar way in 2D, the last one has not been reported in the previous works. The present work is expected to be useful in understanding the Mott transition happening beyond two space dimensions.Comment: 7 pages, no figure
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