2,076 research outputs found

    Testing Endogenous Growth in South Korea and Taiwan

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    We evaluate the endogenous growth hypothesis using sectoral data for South Korea and Taiwan. Our empirical work relies on a direct measure of the variety of products from each sector which can serve as intermediate inputs or as final goods. We test whether changes in the variety of these inputs, for Taiwan relative to Korea, are correlated with the growth in total factor productivity (TFP) in each sector, again measured in Taiwan relative to Korea. We find that changes in relative product variety (entered as either a lag or a lead) have a positive and significant effect on TFP in eight of the sixteen sectors. Seven out of these eight sectors are what we classify as secondary industries, in that they rely on differentiated manufactured inputs, and therefore seem to fit the idea of endogenous growth. Among the primary industries that rely more heavily on natural resources, we find more mixed evidence.

    A balanced homodyne detector for high-rate Gaussian-modulated coherent-state quantum key distribution

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    We discuss excess noise contributions of a practical balanced homodyne detector in Gaussian-modulated coherent-state (GMCS) quantum key distribution (QKD). We point out the key generated from the original realistic model of GMCS QKD may not be secure. In our refined realistic model, we take into account excess noise due to the finite bandwidth of the homodyne detector and the fluctuation of the local oscillator. A high speed balanced homodyne detector suitable for GMCS QKD in the telecommunication wavelength region is built and experimentally tested. The 3dB bandwidth of the balanced homodyne detector is found to be 104MHz and its electronic noise level is 13dB below the shot noise at a local oscillator level of 8.5*10^8 photon per pulse. The secure key rate of a GMCS QKD experiment with this homodyne detector is expected to reach Mbits/s over a few kilometers.Comment: 22 pages, 11 figure

    Tunable Magnetic Properties in Sr2_2FeReO6_6 Double-Perovskite

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    Double-perovskite oxides have attracted recent attention due to their attractive functionalities and application potential. In this paper, we demonstrate the effect of dual controls, i.e., the deposition pressure of oxygen (PO2_O2) and lattice mismatch (ϵ\epsilon), on tuning magnetic properties in epitaxial double-perovskite Sr2_2FeReO6_6 films. In a nearly-lattice-matched Sr2_2FeReO6_6/SrTiO3_3 film, the ferrimagnetic-to-paramagnetic phase transition occurs when PO2_O2 is reduced to 30 mTorr, probably due to the formation of Re4+^{4+} ions that replace the stoichiometric Re5+^{5+} to cause disorders of BB-site ions. On the other hand, a large compressive strain or tensile strain shifts this critical PO2_O2 to below 1 mTorr or above 40 mTorr, respectively. The observations could be attributed to the modulation of BB-site ordering by epitaxial strain through affecting elemental valence. Our results provide a feasible way to expand the functional tunability of magnetic double-perovskite oxides that hold great promise for spintronic devices.Comment: Main text 18 pages, 5 figures; Supplementary information 8 pages, 4 figure

    Isolation and Expression Profile of the Ca2+-Activated Chloride Channel-like Membrane Protein 6 Gene in Xenopus laevis

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    To clone the first anion channel from Xenopus laevis (X. laevis), we isolated a calcium-activated chloride channel (CLCA)-like membrane protein 6 gene (CMP6) in X. laevis. As a first step in gene isolation, an expressed sequence tags database was screened to find the partial cDNA fragment. A putative partial cDNA sequence was obtained by comparison with rat CLCAs identified in our laboratory. First stranded cDNA was synthesized by reverse transcription polymerase-chain reaction (RT-PCR) using a specific primer designed for the target cDNA. Repeating the 5' and 3' rapid amplification of cDNA ends, full-length cDNA was constructed from the cDNA pool. The full-length CMP6 cDNA completed via 5'- and 3'-RACE was 2,940 bp long and had an open reading frame (ORF) of 940 amino acids. The predicted 940 polypeptides have four major transmembrane domains and showed about 50% identity with that of rat brain CLCAs in our previously published data. Semi-quantification analysis revealed that CMP6 was most abundantly expressed in small intestine, colon and liver. However, all tissues except small intestine, colon and liver had undetectable levels. This result became more credible after we did real-time PCR quantification for the target gene. In view of all CLCA studies focused on human or murine channels, this finding suggests a hypothetical protein as an ion channel, an X. laevis CLCA

    Confined lithium–sulfur reactions in narrow-diameter carbon nanotubes reveal enhanced electrochemical reactivity

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    We demonstrate an unusual electrochemical reaction of sulfur with lithium upon encapsulation in narrow-diameter (subnanometer) single-walled carbon nanotubes (SWNTs). Our study provides mechanistic insight on the synergistic effects of sulfur confinement and Li+ ion solvation properties that culminate in a new mechanism of these sub-nanoscale-enabled reactions (which cannot be solely attributed to the lithiation-delithiation of conventional sulfur). Two types of SWNTs with distinct diameters, produced by electric arc (EA-SWNTs, average diameter 1.55 nm) or high-pressure carbon monoxide (HiPco-SWNTs, average diameter 1.0 nm), are investigated with two comparable electrolyte systems based on tetraethylene glycol dimethyl ether (TEGDME) and 1,4,7,10,13-pentaoxacyclopentadecane (15-crown-5). Electrochemical analyses indicate that a conventional solution-phase Li-S reaction occurs in EA-SWNTs, which can be attributed to the smaller solvated [Li(TEGDME)]+ and [Li(15-crown-5)]+ ions within the EA-SWNT diameter. In stark contrast, the Li-S confined in narrower diameter HiPco-SWNTs exhibits unusual electrochemical behavior that can be attributed to a solid-state reaction enabled by the smaller HiPco-SWNT diameter compared to the size of solvated Li+ ions. Our results of the electrochemical analyses are corroborated and supported with various spectroscopic analyses including operando Raman, X-ray photoelectron spectroscopy, and first-principles calculations from density functional theory. Taken together, our findings demonstrate that the controlled solid-state lithiation-delithiation of sulfur and an enhanced electrochemical reactivity can be achieved by sub-nanoscale encapsulation and one-dimensional confinement in narrow-diameter SWNTs.Fil: Fu, Chengyin. University Of California Riverside; Estados UnidosFil: Oviedo, María Belén. University Of California Riverside; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Zhu, Yihan. Zhejiang University Of Technology; ChinaFil: von Wald Cresce, Arthur. U. S. Army Research Laboratory; Estados UnidosFil: Xu, Kang. U. S. Army Research Laboratory; Estados UnidosFil: Li, Guanghui. University Of California Riverside; Estados UnidosFil: Itkis, Mikhail E.. University Of California Riverside; Estados UnidosFil: Haddon, Robert C.. University Of California Riverside; Estados UnidosFil: Chi, Miaofang. Oak Ridge National Laboratory; Estados UnidosFil: Han, Yu. King Abdullah University Of Science And Technology; Arabia SauditaFil: Wong, Bryan M.. University Of California Riverside; Estados UnidosFil: Guo, Juchen. University Of California Riverside; Estados Unido
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