排序方式: 共有45条查询结果,搜索用时 31 毫秒
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W. B. K. Putri D. H. Tran B. Kang N. H. Lee W. N. Kang S. J. Oh 《Journal of Superconductivity and Novel Magnetism》2014,27(2):401-405
We have studied the influence of crystalline SiC buffer layers on the critical current density and on the flux pinning mechanism in MgB2 thin films. Crystalline SiC buffer layers were deposited on the Al2O3 (0001) substrates by using a pulsed laser deposition method, and then MgB2 thin films were grown on the SiC-buffered layer by using a hybrid physical-chemical vapor deposition technique. MgB2 thin films with crystalline SiC-buffered layers showed a significant critical current density’s enhancement in the high magnetic field region. An uncommon plateau-like behavior was also observed when the normalized flux pinning force density was scaled with the reduced magnetic field. Based on the analyses of the scaling behavior of the flux pinning force, grain boundary pinning is likely to be a dominant pinning mechanism in the SiC-buffered MgB2 thin films. 相似文献
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Hermawanto Denny Putri Chery Chaen Dwisetyo Bondan Prasasti Ninuk Ragil Palupi Maharani Ratna Rusjadi Dodi 《Mapan》2020,35(1):81-86
MAPAN - Parameter testing in the sound level meter calibration, such as frequency weighting and linearity, needs precise adjustment of sound level in the decibel (dB) unit. In the... 相似文献
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Putri Setiani Noriaki WatanabeAtsushi Kishita Noriyoshi Tsuchiya 《International Journal of Hydrogen Energy》2013
Hydrogen generation and the concurrent formation of sulfur products from hydrothermal reactions of aqueous sulfide solutions at pH values between 9 and 13 and temperatures between 280 and 330 °C were studied. A hydrogen production model was developed by kinetic and statistical analysis of sulfide consumption rates and the ratio of hydrogen produced to sulfide consumed. Results showed that the amount of hydrogen generated in a given reaction may be predicted by a series of equations incorporating starting conditions such as the initial sulfide concentration, pH and temperature. The data from this study suggested that the overall hydrogen generation reaction mechanism consists of one or more elementary reactions which result in the formation of various sulfur products, such as polysulfides and sulfur oxyanions, depending on the reaction conditions. The possible specific sulfur compounds included pentasulfide (S52−), thiosulfate (S2O32−), trithionate (S3O62−) and sulfate (SO42−). The production rate constants of these products increased with temperature, but were independent of pH. Additionally, it was indicated that increasing the reaction temperature and/or pH resulted in the formation of sulfur products with higher oxidation numbers. This work suggests that the optimal mechanism for hydrogen generation via the sulfur redox cycle, taking into account the requirement for sulfide regeneration, is that which forms trithionate as the sole sulfur product. 相似文献
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A series of titania thin films was prepared by chemical bath deposition (CBD) of TiCl3 on indium tin oxside (ITO) glass at room temperature, followed by calcinations at 500 °C for 4 h. The effect of cyclic deposition on phase composition, microstructure and electrical resistivity of TiO2 thin films was characterised using X-ray diffraction, scanning electron microscopy and four-point probe respectively. Results showed that TiO2 films produced by single deposition cycle were amorphous. In contrast, those produced by 5 and 6 deposition cycles were partly amorphous and partly crystalline with the formation of rutile. Both the film thickness and electrical resistivity increased with an increase in the number of deposition cycles. 相似文献
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Choosing an Appropriate Infection Model to Study Quorum Sensing Inhibition in Pseudomonas Infections
Evelina Papaioannou Putri Dwi Utari Wim J. Quax 《International journal of molecular sciences》2013,14(9):19309-19340
Bacteria, although considered for decades to be antisocial organisms whose sole purpose is to find nutrients and multiply are, in fact, highly communicative organisms. Referred to as quorum sensing, cell-to-cell communication mechanisms have been adopted by bacteria in order to co-ordinate their gene expression. By behaving as a community rather than as individuals, bacteria can simultaneously switch on their virulence factor production and establish successful infections in eukaryotes. Understanding pathogen-host interactions requires the use of infection models. As the use of rodents is limited, for ethical considerations and the high costs associated with their use, alternative models based on invertebrates have been developed. Invertebrate models have the benefits of low handling costs, limited space requirements and rapid generation of results. This review presents examples of such models available for studying the pathogenicity of the Gram-negative bacterium Pseudomonas aeruginosa. Quorum sensing interference, known as quorum quenching, suggests a promising disease-control strategy since quorum-quenching mechanisms appear to play important roles in microbe-microbe and host-pathogen interactions. Examples of natural and synthetic quorum sensing inhibitors and their potential as antimicrobials in Pseudomonas-related infections are discussed in the second part of this review. 相似文献
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Wee-Jun Ong Lutfi Kurnianditia Putri Yoong-Chuen Tan Lling-Lling Tan Neng Li Yun Hau Ng Xiaoming Wen Siang-Piao Chai 《Nano Research》2017,10(5):1673-1696
In this work,we demonstrated the successful construction of metal-free zerodimensional/two-dimensional carbon nanodot (CND)-hybridized protonated g-C3N4 (pCN) (CND/pCN) heterojunction photocatalysts by means of electrostatic attraction.We experimentally found that CNDs with an average diameter of 4.4 nm were uniformly distributed on the surface of pCN using electron microscopy analysis.The CND/pCN-3 sample with a CND content of 3 wt.% showed the highest catalytic activity in the CO2 photoreduction process under visible and simulated solar light.Thisprocess results in the evolution of CH4 and CO.The total amounts of CH4 and CO generated by the CND/pCN-3 photocatalyst after 10 h of visible-light activity were found to be 29.23 and 58.82 μmol·gcatalyst-1,respectively.These values were 3.6 and 2.28 times higher,respectively,than the amounts generated when using pCN alone.The corresponding apparent quantum efficiency (AQE) was calculated to be 0.076%.Furthermore,the CND/pCN-3 sample demonstrated high stability and durability after four consecutive photoreaction cycles,with no significant decrease in the catalytic activity.The significant improvement in the photoactivity using CND/pCN-3 was attributed to the synergistic interaction between pCN and CNDs.This synergy allows the effective migration of photoexcited electrons from pCN to CNDs via wellcontacted heterojunction interfaces,which retards the charge recombination.This was confirmed by photoelectrochemical measurements,and steady-state and time-resolved photoluminescence analyses.The first-principles density functional theory (DFT) calculations were consistent with our experimental results,and showed that the work function of CNDs (5.56 eV) was larger than that of pCN (4.66 eV).This suggests that the efficient shuttling of electrons from the conduction band of pCN to CNDs hampers the recombination of electron-hole pairs.This significantly increased the probability of free charge carriers reducing CO2 to CH4 and CO.Overall,this study underlines the importance of understanding the charge carrier dynamics of the CND/pCN hybrid nanocomposites,in order to enhance solar energy conversion. 相似文献