2,484 research outputs found
Long-Distance Wireless Power Transfer Based on Time Reversal Technique
Wireless power transfer (WPT) using microwave irradiation can set human free from the annoying wires. However, WPT has low energy efficiency due to electromagnetic wave diffraction in the case of indoor non-line-of-sight (NLOS) and causes electromagnetic radiation pollution around the room in the case of indoor line-of-sight (LOS). Time reversal (TR) technique is an inverse operation of time-domain signals and makes full use of the multipath effect. TR technique can improve the efficiency and reduce the pollution due to its unique temporal–spatial focusing effect. We will detail the principles of TR with the finite TR arrays. What’s more, we propose a sequential convex programming (SCP) algorithm based on diode circuit to obtain the optimal frequency point amplitude to further improve energy efficiency. The simulation result shows that the TR-SCP-WPT system model will get the significant energy gain
Determination of the superconducting gap in near optimally doped Bi_2Sr_{2-x}La_xCuO_{6+\delta} (x ~ 0.4) from low-temperature specific heat
Low-temperature specific heat of the monolayer high-Tc superconductor
Bi_2Sr_{2-x}La_xCuO_{6+\delta} has been measured close to the optimal doping
point (x ~ 0.4) in different magnetic fields. The identification of both a T^2
term in zero field and a \sqrt{H} dependence of the specific heat in fields is
shown to follow the theoretical prediction for d-wave pairing, which enables us
to extract the slope of the superconducting gap in the vicinity of the nodes
(v_{\Delta}, which is proportional to the superconducting gap \Delta_0 at the
antinodes according to the standard d_{x^2-y^2} gap function). The v_{\Delta}
or \Delta_0 (~ 12 meV) determined from this bulk measurement shows close
agreement with that obtained from spectroscopy or tunneling measurements, which
confirms the simple d-wave form of the superconducting gap.Comment: 5 pages, 4 figures, 1 tabl
2,2′-{[4,6-Bis(octylamino)-1,3,5-triazin-2-yl]azanediyl}diethanol
In the title compound, C23H46N6O2, the two hydroxy groups are located on opposite sides of the triazine ring. One of the hydroxy groups links with the triazine N atom via an intramolecular O—H⋯N hydrogen bond. Intermolecular O—H⋯N and N—H⋯O hydrogen bonding is observed in the crystal structure. π–π stacking is also observed between parallel triazine rings of adjacent molecules, the centroid–centroid distance being 3.5944 (14) Å
Event Rate of Fast Radio Burst from Binary Neutron-star Mergers
It is proposed that one-off fast radio burst (FRB) with periodic structures
may be produced during the inspiral phase of a binary neutron-star (BNS)
merger. In this paper, we study the event rate of such kind of FRB. We first
investigate the properties of two one-off FRBs with periodic structures (i.e.,
FRB~20191221A and FRB~20210213A) in this scenario, by assuming the fast
magnetosonic wave is responsible for their radio emission. For the luminosities
and periods of these bursts, it is found that the pre-merger BNS with magnetic
field strength is required. This is relatively
high compared with that of the most of the BNSs observed in our Galaxy, of
which the magnetic field is around . Since the observed BNSs
in our Galaxy are the binaries without suffering merger, a credited event rate
of BNS-merger originated FRBs should be estimated by considering the evolution
of both the BNS systems and their magnetic fields. Based on the population
synthesis and adopting a decaying magnetic field of NSs, we estimate the event
rate of BNS-mergers relative to their final magnetic fields. We find that the
rapid merged BNSs tend to merge with high magnetization, and the event rate of
BNS-merger originated FRBs, i.e., the BNS-mergers with both NSs' magnetic field
being higher than is ( of the total BNS-mergers) in redshift .Comment: 11 pages, 2 figures, accepted for publication in Astrophysical
Journa
iTRAQ Quantitative Analysis of Multidrug Resistance Mechanisms in Human Gastric Cancer Cells
Multidrug resistance (MDR) is a major obstacle towards a successful treatment of gastric cancer. However, the mechanisms of MDR are intricate and have not been fully understood. To elucidate the molecular mechanisms of MDR in gastric cancer, we employed the proteomic approach of isobaric tags for relative and absolute quantification (iTRAQ), followed by LC-MS/MS, using the vincristine-resistant SGC7901/VCR cell line and its parental SGC7901 cell line as a model. In total, 820 unique proteins were identified and 91 proteins showed to be differentially expressed in SGC7901/VCR compared with SGC7901. Several differentially expressed proteins were further validated by western blot analysis. Furthermore, the association of MVP, one of the highly expressed proteins in SGC7901/VCR, with MDR was verified. Our study is the first application of iTRAQ technology for MDR mechanisms analysis in gastric cancer, and many of the differentially expressed proteins identified have not been linked to MDR in gastric cancer before, which showed the value of this technology in identifying differentially expressed proteins in cancer
Meta-Analysis of Quantitative Trait Association and Mapping Studies using Parametric and Non-Parametric Models
Meta-analysis is an important method for integration of information from multiple studies. In quantitative trait association and mapping experiments, combining results from several studies allows greater statistical power for detection of causal loci and more precise estimation of their effects, and thus can yield stronger conclusions than individual studies. Various meta-analysis methods have been proposed for synthesizing information from multiple candidate gene studies and QTL mapping experiments, but there are several questions and challenges associated with these methods. For example, meta-analytic fixed-effect models assume homogeneity of outcomes from individual studies, which may not always be true. Whereas random-effect models takes into account the heterogeneity among studies they typically assume a normal distribution of study-specific outcomes. However in reality, the observed distribution pattern tends to be multi-modal, suggesting a mixture whose underlying components are not directly observable. In this paper, we examine several existing parametric meta-analysis methods, and propose the use of a non-parametric model with a Dirichlet process prior (DPP), which relaxes the normality assumptions about study- specific outcomes. With a DPP model, the posterior distribution of outcomes is discrete, reflecting a clustering property that may have biological implications. Features of these methods were illustrated and compared using both simulation data and real QTL data extracted from the Animal QTLdb (http://www.animalgenome.org/cgi-bin/QTLdb/index). The meta analysis of reported average daily body weight gain (ADG) QTL suggested that there could be from six to eight distinct ADG QTL on swine chromosome 1
Analysis of relationship among visual evoked potential, oscillatory potential and visual acuity under stimulated weightlessness
AIM: To observe the influence of head-down tilt simulated weightlessness on visual evoked potential(VEP), oscillatory potentials(OPs)and visual acuity, and analyse the relationship among them. METHODS: Head-down tilt for -6° was adopted in 14 healthy volunteers. Distant visual acuity, near visual acuity, VEP and OPs were recorded before, two days and five days after trial. The record procedure of OPs followed the ISCEV standard for full-field clinical electroretinography(2008 update). RESULTS: Significant differences were detected in the amplitude of P100 waves and ∑OPs among various time points(P<0.05). But no relationship was observed among VEP, OPs and visual acuity. CONCLUSION: Head-down tilt simulated weightlessness induce the rearrange of blood of the whole body including eyes, which can make the change of visual electrophysiology but not visual acuity
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