1,499 research outputs found

    A Dynamic CGE Model: An Application of R&D- Based Endogenous Growth Model Theory

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    An R&D based endogenous growth - applied general equilibrium model is developed from an underlying analytical model which combines Romer's capital variety with Grossman and Helpman's multi-sector open economy model. The transitional dynamics of the analytical model are derived. For numerical implementation, a time discrete empirical model, with an Armington structure, is fit to East Asian data of the social accounting matrix variety. Simulations of trade reform are performed and their static and dynamic effects compared. The transition paths of the state variables are found to have a half-life of five to six periods. A solution of the Social Planner's problem, and interventions which seek to obtain this outcome from the decentralized model are also obtained'.Applied General Equilibrium, Trade, Growth, International Relations/Trade, F11, 031, 041,

    Expression of Caveolin-1 in tongue squamous cell carcinoma by quantum dots

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    Quantum dots (QDs) are a new class of fluorescent probes to detect biomarker expression. The role of caveolin-1 (Cav-1) in tongue squamous cell carcinoma (TSCC) is still unknown. This study aimed to investigate the expression profile of Cav-1 in carcinogenesis and development of TSCC by QDs immunofluorescence histochemistry (QDs-IHC) and discuss the relationship between the Cav-1 expression and the clinicopathological outcomes. QDs-IHC was used to detect Cav-1 expression in tissue microarrays including normal tongue mucosa (NTM; n=10), hyperplastic tongue mucosa (HTM; n=10), tongue pre-cancer lesions (TPL; n=15) and primary tongue squamous cell carcinoma (PTSCC; n=61). Correlations between the Cav-1 expression and clinicopathologic variables were evaluated statistically. Cells positive for Cav-1 were clearly detected and bright images were obtained in a fine, granular pattern at the cell membrane and cytoplasm using QDs-IHC. The rate of Cav-1 immunoreactivity increased progressively from NTM (0%), HTM (0%), TPL (36%) to PTSCC (74%). When compared with each other, there was statistical significance among PTSCC, TPL and NTM as well as among PTSCC, TPL and HTM. Moreover, Cav-1 expression level in PTSCC was correlated positively with clinical stage and histologic grade. QDs-IHC could accurately detect protein location in tongue mucosa. An increased expression of Cav-1 in the stepwise carcinogenesis from NTM, HTM, TPL to PTSCC suggested that Cav-1 might be an oncogene in the development of tongue squamous cell carcinoma

    Determination of Chemical Constituents of the Marine Pulmonate Slug, Paraoncidium reevesii

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    Purpose: To isolate and identify the chemical components of Paraoncidium reevesii.Methods: Silica gel column chromatography was used to isolate the components from petroleum ether and ethyl acetate fractions of the acetone extract, and the structures of the compounds were derived from 1H-nuclear magnetic resonance (1H-NMR), 13C-nuclear magnetic resonance (13C-NMR) and mass spectrometry (MS) analyses and also with the aid of literature data for authenticated samples.Results: Cholesterol (1), baconipyrone D (2), chimyl alcohol (3), batyl alcohol (4), á-monpalmitin (5), stearic acid (6), 3-indolecarboxylic acid (7), uracil (8), thymine (9), uridine (10), thymidine (11) were isolated from the marine slug (Paraoncidium reevesii).Conclusion: All the isolated compounds are being reported here for Paraoncidium reevesii for the first time. The results provide base data for further study of the Onchidiidae as a Chinese traditional remedy for asthma and athlete’s foot.Keywords: Mollusk, Paraoncidium reevesii, Baconipyrone D, Batyl alcohol, Chimyl alcohol Onchidiidae, Marine Pulmonate, Slug, Asthma, Athlete’s foo

    Simulation research on molten steel flowing behavior in wide slab continuous casting mold

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    Research on the flowing behavior of molten steel in the continuous casting mold is the key to promote the smooth process of continuous casting and improve the quality of casting blanks. In this article, a three-dimensional solid model of 230 mm × l 600 mm is created based on actual wide slab mold, and analyze the influence of the casting speed, nozzle angle and immersion depth on the flowing behavior of molten steel. It is concluded that the suitable nozzle angle and immersion depth at a certain casting speed can provide theoretical support for continuous casting efficiently and the process optimization

    Fatigue strengthening of damaged steel members using wire arc additive manufacturing

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    In this study, a directed energy deposition (DED) process called wire arc additive manufacturing (WAAM) is employed for the fatigue strengthening of damaged steel members. Three steel specimens with central cracks were tested under a high-cycle fatigue loading (HCF) regime: (1) the reference specimen; (2) the WAAM-repaired specimen with an as-deposited profile, and (3) the WAAM-repaired specimen machined to reduce stress concentration factors (SCF). The corresponding finite element (FE) simulation of the WAAM process was calibrated using static experimental results, which revealed the main mechanism. The process was found to introduce compressive residual stresses at the crack tip owing to the thermal contraction of the repair. The FE results also revealed that stress concentration exists at the root of the as-deposited WAAM; this stress concentration can be mitigated by machining the WAAM to a pyramid-like shape. The fractography analysis indicated that the cracks were initiated at the WAAM-steel interface, and microscopic observations revealed that the microcracks were arrested by the porosities in the melted interface. The results of this pioneering study suggest that WAAM repair is a promising technique for combating fatigue damage in steel structures

    Dipole-Quadrupole Theory of Surface Enhanced Infrared Absorption and Appearance of Forbidden Lines in the SEIRA Spectra of Symmetrical Molecules

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    The paper presents main aspects of the Dipole-Quadrupole theory of Surface Enhanced Infrared Absorption (SEIRA). It is pointed out the possibility of appearance of the lines, caused by totally symmetric vibrations transforming after the unit irreducible representation, which are forbidden in usual infrared absorption spectra in molecules with sufficiently high symmetry. Observation of such lines in the SEIRA spectra of diprotonated and ethylene, adsorbed on and on mordenites is pointed out. The results well agree with our ideas about surface enhanced optical processes, based on the conception of a strong quadrupole light-molecule interaction, which allows us to develop the SERS and SEHRS theories.Comment: 15 pages,3 figures, 1 tabl

    Anisotropy of antiferromagnetic domains in a spin-orbit Mott insulator

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    The temperature-dependent behavior of magnetic domains plays an essential role in the magnetic properties of materials, leading to widespread applications. However, experimental methods to access the three-dimensional (3D) magnetic domain structures are very limited, especially for antiferromagnets. Over the past decades, the spin-orbit Mott insulator iridate Formula Presented has attracted particular attention because of its interesting magnetic structure and analogy to superconducting cuprates. Here, we apply resonant x-ray magnetic Bragg coherent diffraction imaging to track the real-space 3D evolution of antiferromagnetic ordering inside a Formula Presented single crystal as a function of temperature, finding that the antiferromagnetic domain shows anisotropic changes. The anisotropy of the domain shape reveals the underlying anisotropy of the antiferromagnetic coupling strength within Formula Presented. These results demonstrate the high potential significance of 3D domain imaging in magnetism research
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