Two-dimensional structures of ferroelectric domain inversion in LiNbO3 by direct electron beam lithography

We report on the fabrication of domain-reversed structures in LiNbO3 by means of direct electron beam lithography at room temperature without any static bias. The LiNbO3 crystals were chemically etched after the exposure of electron beam and then, the patterns of domain inversion were characterized by atomic force microscopy (AFM). In our experiment, an interesting phenomenon occurred when the electron beam wrote a one-dimensional (1-D) grating on the negative c-face: a two-dimensional (2-D) dotted array was observed on the positive c- face, which is significant for its potential to produce 2-D and three-dimensional photonic crystals. Furthermore, we also obtained 2-D ferroelectric domain inversion in the whole LiNbO3 crystal by writing the 2-D square pattern on the negative c-face. Such a structure may be utilized to fabricate 2-D nonlinear photonic crystal. AFM demonstrates that a 2-D domain-reversed structure has been achieved not only on the negative c-face of the crystal, but also across the whole thickness of the crystal.Comment: 17 pages, 4 figure

Coordinated workload scheduling in hierarchical sensor networks for data fusion applications

2007-2008 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Extracting CP violation and strong phase in D decays by using quantum correlations in psi(3770)-> D0\bar{D}0 -> (V1V2)(V3V4) and psi(3770)->D0\bar{D}0 -> (V1V2)(K pi)

The charm quark offers interesting opportunities to cross-check the mechanism of CP violation precisely tested in the strange and beauty sectors. In this paper, we exploit the angular and quantum correlations in the D\bar{D} pairs produced through the decay of the psi(3770) resonance in a charm factory to investigate CP-violation in two different ways. We build CP-violating observables in psi(3770) -> D\bar{D} -> (V_1V_2)(V_3 V_4) to isolate specific New Physics effects in the charm sector. We also consider the case of psi(3770) -> D\bar{D} -> (V_1V_2)(K\pi) decays, which provide a new way to measure the strong phase difference delta between Cabibbo-favored and doubly-Cabibbo suppressed D decays required in the determination of the CKM angle gamma. Neglecting the systematics, we give a first rough estimate of the sensitivities of these measurements at BES-III with an integrated luminosity of 20 fb^-1 at psi(3770) peak and at a future Super tau-charm factory with a luminosity of 10^35 cm^-2.s^-1.Comment: 13 pages

Thermoacoustic refrigerator driven by a combustion-powered thermoacoustic engine - Demonstrator of device for rural areas of developing countries

This paper presents the design, construction and experimental evaluation of a demonstrator thermoacoustic refrigerator driven by a combustion-powered thermoacoustic engine. The system was developed to be a low-cost device for users based in remote and rural areas of developing countries. It employs a thermoacoustic engine/refrigerator coupling based on a travelling wave looped-tube configuration because of its relatively good thermal performance and construction simplicity. In the present demonstrator, a propane gas burner is used to simulate the thermal input from biomass combustion which is envisaged to be the source of energy for driving the system. Atmospheric air is applied as working fluid, while the operating frequency of the loop is 58.6 Hz. The location of the refrigerator is optimized experimentally to achieve the maximum cooling performance. So far, the lowest temperature achieved at the cold end of the regenerator is -3.6°C, while the maximum COPR achieved is 1.42%

Comparison between architects and non-architects on perceptions of architectural acoustic environments

The perception of the architectural acoustic environment of both architects and non-architects is important. Through interviews with architects and non-architects, theoretical frameworks on acoustic environment perception for the two groups are created in the present study. The entire perception process is summarised into four steps for both groups: attitude towards the acoustic environment of the building, perception of the acoustic environment design, factors influencing the interpretation, and the outcome of the acoustic environment. Some obvious differences between the two groups were observed. Architects tend to focus on controlling the physical parameters of sound; they recognize that the active design of the acoustic environment is difficult and problematic. Non-architects pay more attention to interpreting and experiencing acoustic environments. They tend to create a good acoustic environment using ideal sound and have a positive attitude towards shaping the acoustic environment. Furthermore, compared to non-architects, architects do not pay enough attention to the various influencing factors that affect users’ interpretations of acoustic environments, and the multiple, long-term, and profound effects (e.g. behavioural, emotional, recovery, and health) of the architectural acoustic environment on users are usually ignored. Correlation analysis of these differences and phenomena reveals that the existing issues of the acoustic environment design initially focuses on two aspects: architects’ understanding of the active architectural acoustic environment design is not sufficient to overcome its inherent limitations, and architects’ understanding of public preferences and demands is insufficient. According to the interviews, the future development direction may lie in the combination of acoustic environment design and architecture, support for architects, effective communication and feedback mechanisms, and the transition of architects’ design thinking

Antioxidantactivity In Vitro And Hepatoprotective Effect Of Phlomis Maximowiczii In Vivo

Background: Anumber of medicinal plants and there compounds played a major role in the treatment of hepatic disorders. They were widely used for the treatment of these disorders, and oxidant stress injury was one of the liver injury mechanisms. The present study evaluated the antioxidant activity and the hepatoprotective effect of each extracts of Phlomis maximowiczii.Materials and Methods: The antioxidant activity was assayed by the methods of ABTS, FRAP and DPPH in vitro. Hepatoprotective effect of P. maximowiczii extracts was examined using carbon tetrachloride-induced acute liver injury in mice.Results: P. maximowiczii n-butanol (PMBU) extract, ABTS (IC50=18.96 μg/mL), DPPH (IC50=25.15 μg/mL), and FRAP (RACT50=2775.6±144.18 μmol/g), showed higher scavenging capacity than that of P. maximowiczii ethyl acetate (PMEA). The n-butanol extract could significantly reduce the level of GPT, GOT and MDA (P<0.05, P<0.001 and P<0.001, respectively) and increase the level of SOD (P<0.001), respectively.Conclusion: The antioxidant activity of n-butanol extract in vitro was related with the level ofMDAand SOD in vivo, and hepatoprotective effect of n-butanol extract also had relationship with its antioxidant activity in vivo.Key words: Phlomis maximowiczii, anti-oxidation, acute liver in jury, carbon tetrachloride