2,457 research outputs found
Structural and optical properties of ZnO nanorods by electrochemical growth using multi-walled carbon nanotube-composed seed layers
We reported the enhancement of the structural and optical properties of electrochemically synthesized zinc oxide [ZnO] nanorod arrays [NRAs] using the multi-walled carbon nanotube [MWCNT]-composed seed layers, which were formed by spin-coating the aqueous seed solution containing MWCNTs on the indium tin oxide-coated glass substrate. The MWCNT-composed seed layer served as the efficient nucleation surface as well as the film with better electrical conductivity, thus leading to a more uniform high-density ZnO NRAs with an improved crystal quality during the electrochemical deposition process. For ZnO NRAs grown on the seed layer containing MWCNTs (2 wt.%), the photoluminescence peak intensity of the near-band-edge emission at a wavelength of approximately 375 nm was enhanced by 2.8 times compared with that of the ZnO nanorods grown without the seed layer due to the high crystallinity of ZnO NRAs and the surface plasmon-meditated emission enhancement by MWCNTs. The effect of the MWCNT-composed seed layer on the surface wettability was also investigated
(7-Dimethylamino-1-hydroxy-3-naphthyl)(morpholino)methanone
In the title compound, C17H20N2O3, the morpholine ring is in a slightly distorted chair form. The crystal structure is stabilized by an intermolecular O—H⋯O hydrogen bond between the H atom of the hydroxyl group and the O atom of a neighbouring carbonyl group. A weak intermolecular C—H⋯π interaction is also present
A new species of torrent catfish, Liobagrus geumgangensis (Teleostei, Siluriformes, Amblycipitidae), from Korea
In a recent survey of populations of the Korean torrent catfish Liobagrus, a distinctive species was discovered from the Geum River and its tributaries flowing into the western coast of Korea, and here described as a new species, L. geumgangensis sp. nov. It is distinguishable from other congeners by a combination of the following characters: I, 8 pectoral fin-rays; 52–56 caudal-fin rays; a relatively short occiput to dorsal-fin origin distance (6.9–9.8% SL); a short pelvic-fin insertion to anal-fin origin distance (11.9–17.3% SL); a long dorsal-fin base (10.6–13.5% SL); 8–9 gill rakers; 5–8 serrations on the pectoral fin; the body and fins are dark yellow, the margins of the dorsal, anal, and caudal fins are dark brown, but the outermost rim is faintly yellow. Analysis of the cytb gene also confirmed that L. geumgangensis is a monophyletic lineage distinct from other congeners
Squeezing Limit of the Josephson Ring Modulator as a Non-Degenerate Parametric Amplifier
Two-mode squeezed vacuum states are a crucial component of quantum
technologies. In the microwave domain, they can be produced by Josephson ring
modulator which acts as a three-wave mixing non-degenerate parametric
amplifier. Here, we solve the master equation of three bosonic modes describing
the Josephson ring modulator with a novel numerical method to compute squeezing
of output fields and gain at low signal power. We show that the third-order
interaction from the three-wave mixing process intrinsically limits squeezing
and reduces gain. Since our results are related to other general cavity-based
three-wave mixing processes, these imply that any non-degenerate parametric
amplifier will have an intrinsic squeezing limit in the output fields.Comment: 6+6 pages, 4 figure
Numerical model of journal bearing lubrication considering a bending stiffness effect
An analysis for operating characteristics of journal bearing lubrication system is performed based on the numerical model. Dynamic bearing lubrication characteristics such as oil film pressure and thickness distribution can be analyzed through a numerical model with an integration of elastohydrodynamics and multi-flexible-body dynamics (MFBD). In particular, the oil film thickness variation by elastic deformation is considered in the elastohydrodynamic analysis by applying the bending stiffness effect of journal. And the oil film thickness variation by the bending stiffness effect is applied to the fluid governing equations to calculate the oil film pressure in the elastohydrodynamic lubrication region. A series of process proposed in this study is available for the analysis of realistic elastohydrodynamic lubrication phenomenon. Also, a numerical example for the journal bearing lubrication system is demonstrated and compared with the experimental results. The numerical results considering the bending stiffness effect show a good agreement with the experimental results
Bound for Gaussian-state Quantum illumination using direct photon measurement
We present bound for quantum illumination with Gaussian state when using
on-off detector or photon number resolving detector, where its performance is
evaluated with signal-to-noise ratio. First, in the case of coincidence
counting, the best performance is given by two-mode squeezed vacuum (TMSV)
state which outperforms coherent state and classically correlated thermal (CCT)
state. However coherent state can beat the TMSV state with increasing signal
mean photon number when using the on-off detector. Second, the performance is
enhanced by taking Fisher information approach of all counting probabilities
including non-detection events. In the Fisher information approach, the TMSV
state still presents the best performance but the CCT state can beat the TMSV
state with increasing signal mean photon number when using the on-off detector.
We also show that displaced squeezed state exhibits the best performance in the
single-mode Gaussian state.Comment: 5 pages, 2 figures, comments welcom
Practical and Optimal Crossover Designs for Clinical Trials
Crossover designs have received great attention in clinical trials, as they allow subjects to serve as their own controls and gain such advantage as higher efficiency and smaller sample size over parallel designs, because the within-subject variability is in general smaller than between-subject variability. Response-adaptive crossover designs allow clinical trials to adapt and respond to the information acquired during the trials to achieve various objectives. Adaptive designs have been considered to allocate more subjects to superior treatments, improve statistical efficiency, reduce the sample size for cost savings, increase the sample size to maintain prespecified statistical power, or include auxiliary information. We focus on an adaptive allocation scheme to maximize the benefits from superior treatments, while maintaining a sufficiently high level of statistical efficiency, controlled by a suitable weight parameter. We review and discuss the strategy of incorporating multiple objectives, while advocating a regression type estimation approach via the Generalized Estimating Equations method. We show that the multiple objectives can be successfully incorporated to construct a spectrum of designs, ranging over various efficiencies and trial outcomes of success. Moreover, the adaptive allocation scheme successfully constructs designs with a desired efficiency, as illustrated by practical two- and three-period designs
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