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Now showing items 113 - 128 of 923

  • Methods of manufacturing solar cell devices

    Embodiments of the present invention are directed to a process for making solar cells. Particularly, embodiments of the invention provide simultaneously co-firing (e.g., thermally processing) metal layers disposed both on a first and a second surface of a solar cell substrate to complete the metallization process in one step. By doing so, both the metal layers formed on the first and the second surfaces of the solar cell substrate are co-fired (e.g., simultaneously thermally processed), thereby eliminating manufacturing complexity, cycle time and cost to produce the solar cell device. Embodiments of the invention may also provide a method and solar cell structure that requires a reduced amount of a metallization paste on a rear surface of the substrate to form a rear surface contact structure and, thus, reduce the cost of the formed solar cell device.
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  • Effects of argon plasma treatment on surface characteristic of photopolymerization PEGDA-HEMA hydrogels

    Guoxin Tan   Rong Chen   Chengyun Ning   Lin Zhang   Xiongjie Ruan and Jingwen Liao  

    The aim of this research was to determine the influence of argon plasma treatment condition on the surface properties of poly(ethylene glycol) diacrylate (PEGDA)–hydroxyethly methacrylate hydrogel films, a kind of scaffold materials for tissue engineering. The changes of surface properties have been evaluated by contact angles, X-ray photoelectron spectra (XPS), and scanning electron microscopy (SEM). From the contact angle measurements of different liquids, the surface free energy of the hydrogel was calculated according to approaches by Owens–Wendt–Kaelble. Results showed that the contact angle of the hydrogel to water decreased remarkably after argon plasma treatment, which was caused by the changes in morphology (SEM images) and chemical composition (XPS results) of the argon plasma-treated surface. The surface free energy increased with the increase of the argon plasma treated time and power, and these increasing was mainly due to the increase of polar component. The XPS results confirmed that plasma oxidation reaction produced oxygen-containing functional groups onto the surface. This functional group played an important role in increasing the hydrophilic properties of the hydrogel.
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  • Corona resistant high voltage bushing assembly

    A corona resistant high voltage bushing assembly includes an insulating sleeve to surround a conductor, a flange located on an outside surface of the insulating sleeve, and a first band of semiconductive glaze located on the outer surface of the insulating sleeve spaced apart from an end of the insulating sleeve.
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  • Antioxidant and immunomodulatory activities of polysaccharides from the roots of Sanguisorba officinalis

    Lin Zhang   Sundar Rao Koyyalamudi   Sang Chul Jeong   Narsimha Reddy   Paul T. Smith   R. Ananthan   T. Longvah  

    The roots of Sanguisorba officinalis are used in traditional Chinese medicine for the treatment of diseases such as inflammation and internal haemorrhage. Several scientific investigations involving extraction and pharmacological studies of terpenoids and triterpenoid glycosides from this herb have been carried out. However, little is known regarding the immunomodulatory and antioxidant properties of polysaccharides from S. officinalis. Hence the polysaccharides from this herb have been investigated here. The hot water extract of S. officinalis has been fractionated using size-exclusion chromatography to obtain four polysaccharide fractions designated as SOP-1, SOP-2, SOP-3 and SOP-4. The range of molecular masses of these fractions were from 280Da to 2000kDa, and their sugar compositions consisted mainly of fructose, glucose, xylose, arabinose, and rhamnose. The antioxidant activities of the crude polysaccharide fractions were evaluated in a biological assay using Saccharomyces cerevisiae, whereas the radical scavenging activity was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Analysis of the immunomodulatory activities of these polysaccharide fractions were measured by using mouse macrophages. Most of the polysaccharide fractions have stimulated the production of nitric oxide and tumour necrosis factor-alpha (TNF-alpha), and also displayed antioxidant activities. These results suggest that the roots of S. officinalis are likely to have therapeutic value for the treatment of cancer. Copyright 2012 Elsevier B.V. All rights reserved.
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  • Moisture flow characteristics during radio frequency vacuum drying of thick lumber

    Lin Zhang   Stavros Avramidis   Savvas G. Hatzikiriakos  

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  • Microstrip Grid and Comb Array Antennas

    Lin Zhang   Wenmei Zhang   Zhang, Y.P.  

    The design of a high-gain microstrip grid array antenna (MGAA) for 24-GHz automotive radar sensor applications is first presented. An amplitude tapering technique utilizing variable line width on the individual radiating element is then applied to lower sidelobe level. Next, the MGAA is simplified to a microstrip comb array antenna (MCAA). The MCAA shows broader impedance bandwidth and lower cross-polarization radiation as compared with those of the MGAA. The MCAA is designed not as a travelling-wave but a standing-wave antenna. As a result, the match load and the reflection-cancelling structure can be avoided, which is important, especially in the millimeter-wave frequencies. Finally, an emphasis is given to 45 deg linearly-polarized MCAA because the radiation with the orthogonal polarization from cars coming from the opposite direction does not affect the radar operation.
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  • Meta-analysis of the effects of statin therapy on endothelial function in patients with diabetes mellitus

    Lin Zhang   DingXu Gong   ShaoHua Li   XianLiang Zhou  

    Background: Controversies exist among trials reporting the effects of statins on endothelial dysfunction in patients with diabetes mellitus (DM). Therefore, we performed a meta-analysis to determine whether statin therapy could improve endothelial dysfunction in patients with DM.Methods: PubMed, Cochrane and Embase were searched for randomized controlled trials of statins. Only trials reporting changes in flow-mediated dilatation (FMD) were included in this analysis. A meta-analysis was performed to assess the relationship between statin therapy and improvements in endothelial dysfunction. Meta-regression and subgroup analyses were done to identify sources of heterogeneity.Results: Ten statin studies (845 patients) were included in this analysis. Statin therapy significantly improved FMD in patients with DM [weighted mean difference (WMD): 0.94%; 95% CI: 0.38%, 1.5%; P < 0.001]. Although heterogeneity among trials was found (I-2: 67%), no significant publication bias was detected. Subgroup analyses showed that patients did not benefit from statin therapy if their body mass index (BMI) was > 27.6 kg/m(2) (four trials; I-2: 0%; WMD: 0.11%; 95% CI: -0.47%, 0.70%; P = 0.70). However, FMD was significantly improved among patients with BMI <= 27.6 kg/m(2) (five trials; I-2: 14%; WMD: 1.52%; 95% CI: 1.19%, 1.85%; P < 0.001). Type 1 diabetes, younger age, lower baseline blood lipid levels and blood pressure were all associated with improvements in FMD. The meta-regression analysis yielded similar results.Conclusion: Statins significantly improved the FMD only in patients with better endothelial functions. The use of FMD in evaluating therapeutic outcomes should be careful in populations at high risk. (C) 2012 Elsevier Ireland Ltd. All rights reserved.
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  • Von Neumann entropy-preserving quantum operations

    Lin Zhang   Junde Wu  

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  • ChemInform Abstract: Copper-Mediated Chelation-Assisted ortho-Nitration of (Hetero)arenes.

    Lin Zhang   Zhenhua Liu   Huiqin Li   Guichun Fang   Badru-Deen Barry   Tuemay Abadi Belay   Xihe Bi   Qun Liu  

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  • Molecular-dynamics investigation of structural transformations of a Cu201 cluster in its melting process

    Lin Zhang   Cai-Bei Zhang   Yang Qi  

    We perform molecular-dynamics calculations to investigate the structural transformation of a copper cluster containing 201 atoms in its melting process within the framework of the embedded-atom method (EAM). Concerning melting, the obtained results reveal that its structural changes are different from those of larger-size clusters containing several hundreds or more atoms and smaller-size clusters containing tens of atoms. The melting process of this Cu 201 cluster involves three stages, firstly some atoms in inner regions of this cluster move into outer regions accompanying the structural transformation of the local atom packing, followed by the continuous interchange of atomic positions, and finally this cluster is wholly disordered. During the temperature increase, the structural changes of different regions determined by atom density profiles result in apparent increases in internal energy. By decomposing peaks of pair distribution functions (PDFs) according to the pair analysis (PA) technique, the local structural patterns are identified for the melting of this cluster.[All rights reserved Elsevier].
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  • All-derivable points in nest algebras

    Lin Zhang   Jun Zhu   Junde Wu  

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  • Criterion for silicon formation in transition metal-silicon diffusion couples

    Lin Zhang   Douglas G. Ivey  

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  • Inhomogeneous oxidation of ZrB2-SiC ultra-high-temperature ceramic particulate composites and its mitigation

    Lin Zhang   Nitin P. Padture  

    The ubiquitous inhomogeneous-oxidation behavior of a prototypical ZrB2-20 vol% SiC ultra-high-temperature ceramic (UHTC) particulate composite is investigated in detail. An innovative approach for enhancing the oxidation resistance of the composite and delaying the onset of its inhomogeneous oxidation is demonstrated. In this approach, a borosilicate glass coating that is highly compatible with the composite is applied to the composite surface a priori. The effect of the borosilicate-glass coating thickness on the homogeneous-oxidation kinetics of the composite is investigated quantitatively and modeled. A new phenomenon is discovered where ZrO2 precipitates of graded size are found to nucleate and grow within the borosilicate-glass layer, both in natively grown and in applied coating, during the oxidation of the composites. This is attributed to the ZrO2-solubility gradient across the borosilicate-glass layer as a result of preferential B2O3 volatilization at the surface.
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  • SUPERCONVERGENT RECOVERIES OF CAREY NON-CONFORMING ELEMENT APPROXIMATIONS

    LIN ZHANG   LIKANG LI  

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  • Optical detector module, measurement system and method of detecting presence of a substance in a test material

    Embodiments of the invention comprise apparatus and methods for detecting the presence of a substance in a test material using a plurality of wavelength-specific couplers (e.g. tilted fiber gratings) which provide a spatially distributed multi-node all-optical measurement system. Each node of the measurement system can comprise an optical module that is sensitive to the intensity of a limited band of wavelengths. The node is thus capable of detecting the presence of an absorption peak in a spectrum without having to obtain the full spectrum. By providing a plurality of optical modules that are sensitive to different wavelengths, the spectral signature of different substances may be monitored without having to measure full spectra. The measurement system may be particularly useful in a process control environment where it is desirable to take measurements of one or more substances in different locations.
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  • Two new triterpenoid saponins fromLysimachia davurica

    Lin Zhang   Baoguo Li   Jingkui Tian   Lizhen Xu   Shilin Yang  

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