300 research outputs found
ASCA observations of two SNRs and NEI analysis
Based on the data from the \asca observation of SNRs Kes79 and W49B, we
present here the analysis of their X-ray spectra and morphologies. The Kes79
spectrum can be well fitted by a single NEI component, and the narrow-band
images of that source show an inhomogeneous distribution of heavy elements. The
heavy elements are richest in the positions S, SE and SW of Kes79, where there
may exist interaction between shocks and molecular clouds implied by radio
observations. For W49B we present here the non-equilibrium ionization (NEI)
analysis based on its emission line diagnostics, and the spectral fit using two
NEI components. The reverse shock in W49B may be still hot and we don't find
evidence for a hotter blast wave in \asca spectra.Comment: Contributed talk in 32nd COSPAR E1.1, 1998, Nagoya. To appear in Adv.
Space Res., 1999, 6 pages, LaTe
Molecular Epidemiologic Analysis of Group A Rotaviruses in Children with Diarrhea in Wuhan City, China, 2007
Rail vehicle dynamic response to a nonlinear physical âin-serviceâ model of its secondary suspension hydraulic dampers
A full nonlinear physical âin-serviceâ model was built for a rail vehicle secondary suspension
hydraulic damper with shim-pack-type valves. In the modelling process, a shim pack
deflection theory with an equivalent-pressure correction factor was proposed, and a Finite
Element Analysis (FEA) approach was applied. Bench test results validated the damper
model over its full velocity range and thus also proved that the proposed shim pack deflection
theory and the FEA-based parameter identification approach are effective. The validated
full damper model was subsequently incorporated into a detailed vehicle
dynamics simulation to study how its key in-service parameter variations influence the
secondary-suspension-related vehicle system dynamics. The obtained nonlinear physical
in-service damper model and the vehicle dynamic response characteristics in this study
could be used in the product design optimization and nonlinear optimal specifications of
high-speed rail hydraulic dampers
Identification of Sitobion avenae F. resistance and genetic diversity of wheat landraces from Qinling Mountains, China
The aphid Sitobion avenae F. is one of the most harmful pests of wheat growth in the world. A primary field screening test was carried out to evaluate the S. avenae resistance of 527 wheat landraces from Shaanxi. The results indicated that 25 accessions (4.74%) were resistant to S. avenae in the three consecutive seasons, of which accession S849 was highly resistant, and seven accessions were moderately resistant. The majority of S. avenae resistant accessions come from Qinling Mountains. Then, the genetic variability of a set of 33 accessions (25 S. avenae resistant and 8 S. avenae susceptible) originating from Qinling Mountains have been assessed by 20 morphological traits and 99 simple sequence repeat markers (SSRs). Morphological traits and SSRs displayed a high level of genetic diversity within 33 accessions. The clustering of the accessions based on morphological traits and SSR markers showed significant discrepancy according to the geographical distribution, resistance to S. avenae and species of accessions. The highly and moderately resistant landrace accessions were collected from the middle and the east part of Qinling Mountains with similar morphology characters, for example slender leaves with wax, lower leaf area, and high ear density. These S. avenae resistant landraces can be used in wheat aphid resistance breeding as valuable resources
Real-Time In Situ Measurements of Industrial Hazardous Gas Concentrations and Their Emission Gross
Single crystal growth and characterizations of Cu0.03TaS2 superconductors
Single crystal of Cu0.03TaS2 with low copper intercalated content was
successfully grown via chemical iodine-vapor transport. The structural
characterization results show that the copper intercalated 2H-Cu0.03TaS2 single
crystal has the same structure of the CdI2-type structure as the parent 2H-TaS2
crystal. Electrical resistivity and magnetization measurements reveal that
2H-Cu0.03TaS2 becomes a superconductor below 4.2 K. Besides, electrical
resistivity and Hall effects results show that a charge density wave transition
occurs at TCDW = 50 K.Comment: 14 pages, 6 figures,revised versio
Protons in near earth orbit
The proton spectrum in the kinetic energy range 0.1 to 200 GeV was measured
by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at
an altitude of 380 km. Above the geomagnetic cutoff the observed spectrum is
parameterized by a power law. Below the geomagnetic cutoff a substantial second
spectrum was observed concentrated at equatorial latitudes with a flux ~ 70
m^-2 sec^-1 sr^-1. Most of these second spectrum protons follow a complicated
trajectory and originate from a restricted geographic region.Comment: 19 pages, Latex, 7 .eps figure
Search for antihelium in cosmic rays
The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle
Discovery during flight STS-91 in a 51.7 degree orbit at altitudes between 320
and 390 km. A total of 2.86 * 10^6 helium nuclei were observed in the rigidity
range 1 to 140 GV. No antihelium nuclei were detected at any rigidity. An upper
limit on the flux ratio of antihelium to helium of < 1.1 * 10^-6 is obtained.Comment: 18 pages, Latex, 9 .eps figure
A Study of Cosmic Ray Secondaries Induced by the Mir Space Station Using AMS-01
The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle physics
experiment that will study cosmic rays in the to range and will be installed on the International Space Station
(ISS) for at least 3 years. A first version of AMS-02, AMS-01, flew aboard the
space shuttle \emph{Discovery} from June 2 to June 12, 1998, and collected
cosmic ray triggers. Part of the \emph{Mir} space station was within the
AMS-01 field of view during the four day \emph{Mir} docking phase of this
flight. We have reconstructed an image of this part of the \emph{Mir} space
station using secondary and emissions from primary cosmic rays
interacting with \emph{Mir}. This is the first time this reconstruction was
performed in AMS-01, and it is important for understanding potential
backgrounds during the 3 year AMS-02 mission.Comment: To be submitted to NIM B Added material requested by referee. Minor
stylistic and grammer change
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