481 research outputs found

    Causal Relationship among the National Wealth, the Consumption and Shanghai Composite Index

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    Based on data between the December 1990 to July 2009 of the industrial added value, retail sales and the Shanghai composite index, Cointegration and Granger Causality test have been done and found that: a) An stable cointegration relationship exists among the industrial added value, retail sales and Shanghai composite index, and they are positively correlated. b) The total industrial added value and retail sales Granger cause the Shanghai composite index, but the reverse affect did not observed, which explain China's stock market is not yet a mature market. c) Compared to the total retail sales, the impact of industrial added value on the Shanghai composite index delayed a little longer.Keywords: cointegration test; Granger causality test; industrial added value; total retail sales; the Shanghai Composite Inde

    Ripple Effect of Housing Prices Fluctuations among Nine Cities of China

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    This paper applies cointegration test, error correction model, vector error correction model, impulse response analysis and variance decomposition to examine the ripple effect of housing prices fluctuations among Chinese cities during the period of first quarter of 1999 to third quarter of 2008. Empirical analysis indicates that housing prices fluctuations among nine Chinese cities do have ripple effect. We divide the cities into three layers: Beijing, Shanghai as the first layer; Shenyang, Tianjin and Xi’an as the second; and Qingdao, Chongqing, Guangzhou and Dalian as the third one. Empirical results show that: (1) housing prices of municipalities directly under the central government such as Beijing and Shanghai representing the first layer have strong influence and still be the main regulatory objects; (2) cities in the second layer can transmit the fluctuations of housing prices and should be concerned; (3) intense fluctuations of housing prices of cities in the third layer should be avoided. So, the government should make targeted regulatory policies to cities in different layers, which is a more efficient way to control the whole system of housing prices, maintain housing prices in a reasonable range, and eventually achieve the goal of building a harmonious society.Key Words: housing prices; ripple effect; cointegration test; error correction model; vector error correction mode

    A potential third-generation gravitational-wave detector based on autocorrelative weak-value amplification

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    Reducing noises and enhancing signal-to-noise ratios (SNRs) have become critical for designing third-generation gravitational-wave (GW) detectors with a GW strain of less than 102310^{-23}/Hz\rm \sqrt{Hz}. In this paper, we propose a potential third-generation GW detector based on autocorrelative weak-value amplification (AWVA) for GW detection with a strain of hg=h_g = 4×10254 \times 10^{-25}/Hz\rm \sqrt{Hz}. In our scheme, a GW event induces a phase difference Δϕ\Delta \phi by passing through an 11-bounce delay line, 10-km arm-length, zero-area Sagnac interferometer illuminated with a 1064-nm laser. Subsequently, Δϕ\Delta \phi is amplified as the parameter of post-selection by choosing the appropriate pre-selected state and coupling strength in AWVA. In particular, we theoretically investigate the AWVA measurements for GW detection within the frequency band of 200 Hz \leq fgf_g \leq 800 Hz, considering Gaussian noises with negative-decibel SNRs. The peak response of the AWVA sensitivity κ(fg)\kappa(f_g) occurs at frequency fg,maxf_{g, max} = 500 Hz, which falls within the frequency band of interest of the current third-generation GW detectors. Our simulation results indicate that AWVA can demonstrate a measurable sensitivity of Θ(fg)\Theta(f_g) within the frequency band of interest. Moreover, the robustness of WVA shows promising potential in mitigating the effects of Gaussian noises.Comment: 21 pages, 6 figure

    Association of ABCC2 and CDDP-Resistance in Two Sublines Resistant to CDDP Derived from a Human Nasopharyngeal Carcinoma Cell Line

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    Cisplatin (CDDP) is one of the most active drugs to treat nasopharyngeal carcinoma (NPC) patients. To further understand the mechanisms of CDDP-resistance in NPC, two CDDP-resistant sublines (CNE2-CDDP and CNE2-CDDP-5Fu) derived from parental NPC cell line CNE2 were established. It was found that at the IC50 level, the resistance of CNE2-CDDP and CNE2-CDDP-5Fu against CDDP was 2.63-fold and 5.35-fold stronger than that of parental CNE2, respectively. Of the four ABC transporters (ABCB1, ABCC1, ABCC2 and ABCG2) related to MDR, only ABCC2 was found to be elevated both in CDDP-resistant sublines, with ABCC2 located in nucleus of CNE2-CDDP-5Fu but not in CNE2-CDDP and parental CNE2. Further research showed that compared to untreated CNE2, the intracellular levels of CDDP were decreased by 2.03-fold in CNE2-CDDP and 2.78-fold in CNE2-CDDP-5Fu. After treatment with PSC833, a modulator of MDR associated transporters including ABCC2, the intracellular level of CDDP was increased in CDDP-resistant sublines, and the resistance to CDDP was partially reversed from 2.63-fold to 1.62-fold in CNE2-CDDP and from 5.35-fold to 4.62-fold in CNE2-CDDP-5Fu. These data indicate that ABCC2 may play an important role in NPC resistant to CDDP

    Comparison of microstructure, crystallographic texture, and mechanical properties in Ti–15Mo–5Zr–3Al alloys fabricated via electron and laser beam powder bed fusion technologies

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    Depending on the application, establishing a strategy for selecting the type of powder bed fusion technology—from electron beam (EB-PBF) or laser powder bed fusion (L-PBF)—is important. In this study, we focused on the β-type Ti–15Mo–5Zr–3Al alloy (expected for hard-tissue implant applications) as a model material, and we examined the variations in the microstructure, crystallographic texture, and resultant mechanical properties of specimens fabricated by L-PBF and EB-PBF. Because the melting mode transforms from the conduction mode to the keyhole mode with an increase in the energy density in L-PBF, the relative density of the L-PBF-built specimen decreases at higher energy densities, unlike that of the EB-PBF-built specimen. Although both EB-PBF and L-PBF can obtain cubic crystallographic textures via bidirectional scanning with a 90° rotation in each layer, the formation mechanisms of the textures were found to be different. The texture in the build direction is mainly derived from the vertically grown columnar cells in EB-PBF, whereas it is derived from the vertically and horizontally grown columnar cells in L-PBF. Consequently, different textures were developed via bidirectional scanning without rotation in each layer: the and aligned textures along the build direction in L-PBF and EB-PBF, respectively. The L-PBF-built specimen exhibited considerably better ductility, but slightly lower strength than the EB-PBF-built specimen, under the conditions of the same crystallographic texture and relative density. We attributed this to the variation in the microstructures of the specimens; the formation of the α-phase was completely absent in the L-PBF-built specimen. The results demonstrate the importance of properly selecting the two technologies according to the material and its application.Sun S.H., Hagihara K., Ishimoto T., et al. Comparison of microstructure, crystallographic texture, and mechanical properties in Ti–15Mo–5Zr–3Al alloys fabricated via electron and laser beam powder bed fusion technologies. Additive Manufacturing, 47, 102329. https://doi.org/10.1016/j.addma.2021.102329

    Efficient manganese luminescence induced by Ce3+-Mn2+ energy transfer in rare earth fluoride and phosphate nanocrystals

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    Manganese materials with attractive optical properties have been proposed for applications in such areas as photonics, light-emitting diodes, and bioimaging. In this paper, we have demonstrated multicolor Mn2+ luminescence in the visible region by controlling Ce3+-Mn2+ energy transfer in rare earth nanocrystals [NCs]. CeF3 and CePO4 NCs doped with Mn2+ have been prepared and can be well dispersed in aqueous solutions. Under ultraviolet light excitation, both the CeF3:Mn and CePO4:Mn NCs exhibit Mn2+ luminescence, yet their output colors are green and orange, respectively. By optimizing Mn2+ doping concentrations, Mn2+ luminescence quantum efficiency and Ce3+-Mn2+ energy transfer efficiency can respectively reach 14% and 60% in the CeF3:Mn NCs

    Searching for dark-matter induced neutrino signals in dwarf spheroidal galaxies using 10 years of IceCube public data

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    This study searches for neutrino signals from 18 dwarf spheroidal galaxies (dSphs) using 10 years of publicly available muon-track data of the IceCube neutrino observatory. We apply an unbinned likelihood analysis on each of these dSphs to derive the significance the putative neutrino emission. To further enhance our sensitivity, we also stack all dSphs together to perform a joint analysis. However, no significant neutrino emission signal was detected in either the single-source or stacking analysis. Based on these null results, we derive constraints on the annihilation cross section of dark matter particles. Compared to the existing literature, our constraints via the channel χχμ+μ\chi\chi\rightarrow\mu^+\mu^- are comparable to the ones from the VERITAS observations of dSphs
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