841 research outputs found

    Photoresponsive and Ultraviolet to Visible-Light Range Photocatalytic Properties of ZnO:Sb Nanowires

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    100學年度研究獎補助論文[[abstract]]Zinc oxide (ZnO) doped antimony (Sb) nanowires have been synthesized for improving ultraviolet sensing and photocatalytic properties. Upon illumination by UV light (365nm , 2.33mWcm−2 ), the photoelectric current of the ZnO:Sb nanowires exhibited a rapid photoresponse as compared to that of the ZnO nanowires. A highest ratio of photocurrent to dark current of around 48.8-fold was achieved in the as-synthesized ZnO:Sb nanowires. A UV-visible spectrophotometer was used to investigate the absorbance spectrum of the ZnO:Sb nanowires, which exhibited a high absorbance ratio with redshift effect in contrast to that of the ZnO nanowires. Visible-light photocatalysis and UV photoresponsive properties of the ZnO:Sb nanowires are superior to those of the ZnO nanowires.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]電子

    Defect formation during preforming of a bi-axial non-crimp fabric with a pillar stitch pattern

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    To capture the asymmetrical shear behaviour of a bi-axial NCF with a pillar stitch, a non-orthogonal constitutive model was developed and implemented in finite element forming simulations. Preforming experiments indicate that the local distribution of defects is significantly different on both sides of each bi-axial ply, with two different defect mechanisms observed. Correlation with simulation results indicates that one defect type is caused by excessive shear, inducing out-of-plane wrinkling in regions of positive shear (macro-scale wrinkling). The other defect type is caused by fibre compression, inducing in-plane wrinkling in regions of negative shear (meso-scale wrinkling). Local distributions of shear angle and wrinkling strain were used to determine the wrinkling mode and to confirm the corresponding defect mechanism. Results indicate that simulations based on the advanced constitutive model can predict local shear angles within ±5°of experimental values and that predicted wrinkling positions and defect types correlate well with the experiments

    Detection of diffuse and specular interface reflections and inter-reflections by color image segmentation

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    We present a computational model and algorithm for detecting diffuse and specular interface reflections and some inter-reflections. Our color reflection model is based on the dichromatic model for dielectric materials and on a color space, called S space, formed with three orthogonal basis functions. We transform color pixels measured in RGB into the S space and analyze color variations on objects in terms of brightness, hue and saturation which are defined in the S space. When transforming the original RGB data into the S space, we discount the scene illumination color that is estimated using a white reference plate as an active probe. As a result, the color image appears as if the scene illumination is white. Under the whitened illumination, the interface reflection clusters in the S space are all aligned with the brightness direction. The brightness, hue and saturation values exhibit a more direct correspondence to body colors and to diffuse and specular interface reflections, shading, shadows and inter-reflections than the RGB coordinates. We exploit these relationships to segment the color image, and to separate specular and diffuse interface reflections and some inter-reflections from body reflections. The proposed algorithm is effications for uniformly colored dielectric surfaces under singly colored scene illumination. Experimental results conform to our model and algorithm within the liminations discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41303/1/11263_2004_Article_BF00128233.pd

    Systematic review of the effect of reflective materials around a phototheraphy unit on biirubin reduction among neonates with physiologic jaundice in developing countries

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    Objective: To identify the efficacy and safety of the use of various cost-effective reflective materials around phototherapy units to reduce the duration of phototherapy and hasten the reduction of bilirubin among neonates with physiologic jaundice. Data Sources: A systematic review of randomized controlled trials identified from searches in the Cumulative Index to Nursing and Allied Health Literature, Science Direct, Embase, and the Cochrane Library with the use of keywords, MeSH terms, operators, and the review of reference lists of retrieved articles. Study Selection: From a total of 186 studies initially screened, five were eventually included in this analysis. Data Extraction: Two authors independently reviewed each study with a standard template. Review parameters included the quality of each study based on the Physiotherapy Evidence Database scale and the Consolidated Standards of Reporting Trials guidelines. Data Synthesis: All studies were generalizable and were rated as high quality on the Physiotherapy Evidence Database scale; one study scored 8 points, and the other four scored 6 points each. The reflective materials used in these studies included the following: white 100% cotton cloths (one study), white plastic covers (two studies), underpads (one study), and silver fabric cloth (one study). Pooled analysis of three studies indicated that reflective materials significantly reduced the duration of phototherapy with a large effect size of 0.82 (p =.04). Pooled analysis of another three studies indicated that the mean decrease of the total serum bilirubin 4 hours after the initiation of phototherapy was significantly greater when reflective materials were added (mean difference of 11.39 μmol/L, 95% confidence interval [2.26, 20.52 μmol/L], p =.01). Conclusion: The addition of reflective materials to phototherapy units may be therapeutic for neonates with physiologic jaundice

    Sustaining tropical timber trees in production forests of Asia - ensuring their genetic viability

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    Sustainable timber production in approximately 400 million hectares of production forests in the tropics would be enhanced by incorporating genetic conservation measures in their management. This factsheet, based on a scientific review, explains why tropical Asian timber species are particularly vulnerable to logging and habitat fragmentation and what policymakers and forest managers can do to maintain productivity and resilience of timber trees in Asian production forests

    A large class of non constant mean curvature solutions of the Einstein constraint equations on an asymptotically hyperbolic manifold

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    We construct solutions of the constraint equation with non constant mean curvature on an asymptotically hyperbolic manifold by the conformal method. Our approach consists in decreasing a certain exponent appearing in the equations, constructing solutions of these sub-critical equations and then in letting the exponent tend to its true value. We prove that the solutions of the sub-critical equations remain bounded which yields solutions of the constraint equation unless a certain limit equation admits a non-trivial solution. Finally, we give conditions which ensure that the limit equation admits no non-trivial solution.Comment: remark on the equivalence between the existence of a solution to the Lichnerowicz equation and to the prescribed scalar curvature equation added, reference [BPB09] added, to appear in Commun. Math. Phy

    Evolution of the Southwest Australian Rifted Continental Margin During Breakup of East Gondwana: Results from IODP Expedition 369

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    International Ocean Discovery Program Expedition 369 drilled four sites on the southwestern Australian continental margin, in the deep water Mentelle Basin (MB) and on the neighboring Naturaliste Plateau (NP). The drillsites are located on continental crust that continued rifting after seafloor spreading began further north on the Perth Abyssal Plain (PAP) between magnetochrons M11r and M11n (133‐132 Ma), ending when spreading began west of the NP between chrons M5n and M3n (126‐124 Ma). Drilling recovered the first in‐situ samples of basalt flows overlying the breakup unconformity on the NP, establishing a magnetostratigraphically constrained eruption age of >131‐133 Ma and confirming a minimal late Valanginian age for the breakup unconformity (coeval with the onset of PAP seafloor spreading). Petrogenetic modeling indicates the basalts were generated by 25% melting at 1.5 GPa and a potential temperature of 1380‐1410 °C, consistent with proximity of the Kerguelen plume during breakup. Benthic foraminiferal fossils indicate that the NP remained at upper bathyal or shallower depths during the last 6 Myr of rifting and for 3‐5 Myr after breakup between India and Australia. The limited subsidence is attributed to heat from the nearby Kerguelen plume and PAP spreading ridge. The margin subsided to middle bathyal depths by Albian time and to lower bathyal (NP) or greater (MB) depths by late Paleogene time. Periods of rapid sedimentation accompanied a westward jump of the PAP spreading ridge (108 Ma), rifting on the southern margin (100‐84 Ma), and opening of the southern seaway between Australia and Antarctica (60‐47 Ma)

    Business ethics : practical proposals

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    While most people agree that the inculcation of ethical awareness is desirable, the means of stimulating this awareness vary among companies, industries and cultures. The fundamental question surrounding the difference between social responsibility and ethics is addressed. Guidelines for establishing ethical priorities from both the individual, group and organisational perspectives are provided. <br /
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