4,412 research outputs found
IPS Observation System for Miyun 50m Radio Telescope and Its Acceptance Observation
Ground-based observation of Interplanetary Scintillation(IPS) is an important
approach of monitoring solar wind. A ground-based IPS observation system is
newly implemented on 50m radio telescope, Miyun station, National Astronomical
Observatories, Chinese Academy of Sciences(NAOC). This observation system is
constructed for purpose of observing the solar wind speed and scintillation
index by using the normalized cross-spectrum of simultaneous dual-frequency IPS
measurement. The system consists of a universal dual-frequency front-end and a
dual-channel multi-function back-end specially designed for IPS. After careful
calibration and testing, IPS observations on source 3C273B and 3C279 are
successfully carried out. The preliminary observation results show that this
newly developed observation system is capable of doing IPS observation.The
system sensitivity for IPS observation can reach over 0.3Jy in terms of IPS
polarization correlator with 4MHz bandwidth and 2s integration time.Comment: 8 pages, 7 figure
Biomechanical analysis of the acetabular buttress-plate: are complex acetabular fractures in the quadrilateral area stable after treatment with anterior construct plate-1/3 tube buttress plate fixation?
OBJECTIVE: The acetabular buttress-plate has been widely used in treating difficult cases with satisfying clinical results. However, the biomechanical properties of a postoperative acetabular fracture fixed by the buttress-plate are not clear. The purpose of this study was to evaluate the biomechanical properties of stability after the anterior tube buttress-plate fixation of complex acetabular fractures in the quadrilateral area. METHODS: A construct was proposed based on anterior construct plate - 1/3 tube buttress plate fixation for acetabular both-column fractures. Two groups of six formalin-preserved cadaveric pelvises were analyzed: (1) group A, the normal pelvis and (2) group B, anterior construct plate-1/3 tube buttress plate with quadrilateral area fixation. The displacements were measured, and cyclical loads were applied in both standing and sitting simulations. RESULTS: As the load was added, the displacements were
Determination and pharmacokinetic study of catechin in rat plasma by HPLC
AbstractA high performance liquid chromatographic method was developed and validated for the quantitative determination of catechin in rat plasma and its pharmacokinetic study after intragastric administration of Catechu and Xiongdanjiangre Wan into SD rats. Plasma samples were prepared by protein precipitation using methanol–5% aqueous zinc sulfate (70:30, v/v) as precipitant. Chromatographic separation was achieved on Hypersil C18 column (250mm×4.6mm, 10μm) with acetonitrile–water–triethylamine (6:94:0.3, v/v/v, pH 4.0±0.1, adjusted with phosphoric acid) as mobile phase, followed by a UV detection at 207nm. Good linearity was obtained over the range of 0.143–7.15mg/L of catechin, with correlation coefficient of 0.9992. The method was simple, sensitive, accurate and reproducible and has been successfully applied to the pharmacokinetic study of catechin in rat plasma
The global spatiotemporal distribution of the mid-tropospheric CO2 concentration and analysis of the controlling factors
The atmospheric infrared sounder (AIRS) provides a robust and accurate data source to investigate the variability of mid-tropospheric CO2 globally. In this paper, we use the AIRS CO2 product and other auxiliary data to survey the spatiotemporal distribution characteristics of mid-tropospheric CO2 and the controlling factors using linear regression, empirical orthogonal functions (EOFs), geostatistical analysis, and correlation analysis. The results show that areas with low mid-tropospheric CO2 concentrations (20 degrees S-5 degrees N) (384.2 ppm) are formed as a result of subsidence in the atmosphere, the presence of the Amazon rainforest, and the lack of high CO2 emission areas. The areas with high mid-tropospheric CO2 concentrations (30 degrees N-70 degrees N) (382.1 ppm) are formed due to high CO2 emissions. The global mid-tropospheric CO2 concentrations increased gradually (the annual average rate of increase in CO2 concentration is 2.11 ppm/a), with the highest concentration occurring in spring (384.0 ppm) and the lowest value in winter (382.5 ppm). The amplitude of the seasonal variation retrieved from AIRS (average: 1.38 ppm) is consistent with that of comprehensive observation network for trace gases (CONTRAIL), but smaller than the surface ground stations, which is related to altitude and coverage. These results contribute to a comprehensive understanding of the spatiotemporal distribution of mid-tropospheric CO2 and related mechanisms
3-(10-Chloro-9-anthryl)-5-[3-(prop-2-ynyloxy)phenoxymethyl]isoxazole
In the title molecule, C27H18ClNO3, the anthracene mean plane forms dihedral angles of 67.43 (2) and 15.75 (3)° with the isoxazole and benzene rings, respectively. In the crystal structure, C—H⋯π interactions link molecules into centrosymmetric dimers, which are further linked by weak intermolecular C—H⋯N hydrogen bonds into ribbons propagating in the [110] direction
Bounds for multipartite concurrence
We study the entanglement of a multipartite quantum state. An inequality
between the bipartite concurrence and the multipartite concurrence is obtained.
More effective lower and upper bounds of the multipartite concurrence are
obtained. By using the lower bound, the entanglement of more multipartite
states are detected.Comment: 8 page
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