检索结果-南通市图书馆

The investigation of the Neupert effect in two solar flares

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2009年第11期52卷 1686-1690页

作者： NING ZongJun purple mountain observatory, nanjing 210008, china purple mountain observatory Nanjing China

The Neupert effect suggests a flare model in which the nonthermal emissions are produced by energetic electrons which heat lower corona and chromosphere to produce the thermal emissions. Based on this concept, we investigate the Neupert effect to test the correlation between the hard X-ray spectral index and the time rate of the UV flare area at 1600 or 171 . Using the T RACE and RHESSI observations, we explore these quantities for two solar flares, one on March 14, 2002 and the other on November 1, 2003. The negative dependence between the spectral index and the time rate of the UV flare area is found, especially during the hard X-ray sub-peaks. This finding indicates that the electron-beam-driven heating plays a prominent role in the UV emission of these two flares.

关键词： solar flares UV radiation X-rays

The simulation of GCRs at near earth interplanetary locations for radioprotection

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1739-1745页

作者： BAO Gang purple mountain observatory,Chinese Academy of Sciences,nanjing 210008,china purple mountain observatory Chinese Academy of Sciences Nanjing China

The interplanetary radiation environment is detrimental to space missions,giving rise to cumulative damage to both astronauts and payloads and enhanced background levels in ***,there is a pressing need for a reliable simulation of these harmful effects for risk assessment and shielding optimization in manned space *** have modeled the interaction processes of the two most abundant galactic cosmic ray particle fluxes(protons and helium nuclei) using the Geant4 toolkit for a given space vehicle *** total energy deposited due to protons and helium nuclei is calculated in this work,and the energy deposited due to the secondary particles generated by this radiation is also estimated.

关键词： radioprotection simulation Geant4 cosmic rays

Diagnostics of magnetic field strength for gyrosynchrotron radiation regions of the lower harmonics

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第14期43卷 1183-1187页

作者： ZHOU Aihua purple mountain observatory, Chinese Academy of Sciences, nanjing 210008, china purple mountain observatory Chinese Academy of Sciences Nanjing China

A diagnostic formula of magnetic field strength of gyrosynchrotron radiation regions of the lower harmonics (5 ≤S≤10 ) is presented based on their emissivity η νBN , absorptivity κ νBN , and the turnover frequency of radio spectra ν P. Their diagnostic error is estimated. And an accurate relation between electron energy spectral index δ and brightness temperature spectral index β is also given.

关键词： lower harmonic radio emission magnetic field.

Comparative study of the relationships between CO isotopic luminosities and infrared luminosity for the Galactic dense cores

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2010年第6期53卷 1169-1178页

作者： SUN Yan & GAO yu purple mountain observatory,Chinese Academy of Sciences,nanjing 210008,china purple mountain observatory Chinese Academy of Sciences Nanjing China

Combining the 12CO(1-0),13CO(1-0),and C18O(1-0) data with IRAS four band data,we here estimate the physical parameters such as size,viral mass,and CO J=1-0 isotopic and infrared luminosities for 29 dense molecular clouds from two published CO samples. We further analyze the various correlations between CO J=1-0 isotopic luminosities and infrared luminosity(star formation rate,SFR) and discuss the relationships between the molecular gas tracers and SFR. The results show that 12CO(1-0),13CO(1-0) and C18O(1-0) luminosities have tight correlations with each other. CO J=1-0 isotopic luminosities and SFR show weak correlations with larger scatter than the HCN-IR correlations of 47 dense cores in the Galaxy and 65 external star-forming galaxies. This might be interpreted as that both the SFR and star formation efficiency are mainly determined by the molecular gas at high volume density rather than high column density.

关键词： ISM molecular clouds radio lines star formation

Multiwavelength study of low-luminosity 6.7-GHz methanol masers

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2011年第2期11卷 137-155页

作者： yuan-Wei Wu,Ye Xu and Ji Yang purple mountain observatory,Chinese Academy of Sciences,nanjing 210008,china purple mountain observatory Chinese Academy of Sciences Nanjing 210008 China

We present results of 13CO（1-0）,C18O（1-0）,and HCO＋（1-0） map observations and N2H＋（1-0） single point observations directed towards a sample of nine low-luminosity 6.7-GHz masers.N2H ＋ line emission has been detected from six out of nine sources,C18O line emission has been detected from eight out of nine sources,and HCO ＋ and 13CO emission has been detected in all *** particular,a ＂blue profile＂ of the HCO ＋ spectrum,a signature of inflow,is found towards one *** integrated intensity emission maps,we identified 17 cores in the *** them,nine cores are closely associated with low-luminosity methanol *** these cores,we derive the column densities,core sizes,masses and molecular *** of our results with similar molecular line surveys towards the southern sky methanol masers indicates that linewidths of our sample,including only the low-luminosity masers,are smaller than the sample that includes both lowand high-luminosity *** the maser associated cores,their gas masses have the same order of magnitude as their virial masses,indicating that these cores are gravitationally bound *** addition,we have found from our observations that the low-luminosity methanol masers tend to coexist with H2O masers and outflows rather than with OH masers.

关键词： masers -- ISM: abundances -- ISM: molecules -- stars: formation

Near-Infrared Observations of the Massive Star Forming Region IRAS 23151+5912

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2004年第3期4卷 284-298页

作者： Xue-Peng Chen Yong-Qiang Yao purple mountain observatory Chinese Academy of Sciences, nanjing 210008 purple mountain observatory Chinese Academy of Sciences Nanjing 210008

Near-infrared images and K-band spectroscopy of the massive star-formingregion IRAS 23151+5912 are presented. The JHK′ images reveal an embedded infrared clusterassociated with infrared nebula, and the H_2 (2.12 μm) narrowband image provides for the first timeevidence of outflow activity associated with the cluster. That the cluster is young can be shown bythe high percentage of infrared excess sources and the outflow activity. We suggest an age of thecluster of ～ 10~6 yr. Eight young stars are found in the bright nebular core around IRAS23151+5912. By the color-magnitude diagrams of the cluster, we found five high-mass YSOs and fourintermediate-mass YSOs in the cluster. Eight H_2 emission features are discovered in the region witha scattered and non-axisymmetric distribution, indicating the existence of multiple outflows drivenby the cluster. Diffuse H_2 emission detected to the north and to the west of the cluster mayresult from UV leakage of the cluster. Brγ, H_2, and CIV emission lines are found in the K-bandspectrum of the brightest source, NIRS 19, indicating the presence of envelope, stellar wind, andshock in the circumstellar environment. We have estimated an O7-O9 spectral type for the centralmassive YSO (20 ～ 30 solar mass), with an age of less than 1 x 10~6 yr.

关键词： infrared radiation stars: formation ISM: individual: IRAS 23151 + 5912 ISM: jets and outflows

The red damping wing of Gunn-Peterson trough in the high redshift GRBs

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2009年第9期52卷 1428-1433页

作者： XU Zhou1,2 & WEI DaMing1,3 1 purple mountain observatory, Chinese Academy of Sciences, nanjing 210008, china 2 Graduate University of Chinese Academy of Sciences, Beijing 100012, china 3 Joint Center for Particle Nuclear Physics and Cosmology of purple mountain observatory-nanjing University, nanjing 210008, china purple mountain observatory Chinese Academy of Sciences Nanjing China Graduate University of Chinese Academy of Sciences Beijing China Joint Center for Particle Nuclear Physics and Cosmology of purple mountain observatory-nanjing University Nanjing China

We calculate the red damping wing of Gunn-Peterson trough taking the evolution of the neutral fraction into consideration and take a clear look at the ionized region around the ionizing sources. We get the result that the damping wing flux feature is mainly determined by the neutral hydrogen outside the ionized bubble and the cut off in the damping wing would be useful to get the size of the ionized bubble. We also fit the red damping wing of the recently discovered high redshift GRB080913 and find that the ionized bubble is too small to create apparent cut off in the spectrum of this burst.

关键词： cosmology theory intergalactic medium gamma ray burst

Test mass charging simulation of ASTROD I due to solar energetic particles at 0.5 AU

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2010年第6期53卷 1139-1143页

作者： BAO Gang & LIU Lei purple mountain observatory,Chinese Academy of Sciences,nanjing 210008,china purple mountain observatory Chinese Academy of Sciences Nanjing China

Maintaining the geodesic motion of the test mass is vital to ASTROD I space mission. However,the electrostatic charging of the test mass due to cosmic rays and solar energetic particles will result in Coulomb and Lorentz forces and consequently influence the test mass motions. To estimate the size of these effects,a credible simulation of test mass charging processes is critically required. Using the GEANT4 software toolkit,we have modeled the charging processes and predict how the ASTROD I test mass will charge positively at a rate of 217370 e + /s,due to solar energetic particles(SEPs) at～0.5 AU caused by the largest SEPs event on 29,September,1989. In addition to Monte Carlo uncertainty,an error of ±30% in the net charging rates was added to account for uncertainties in the spectra,physics and geometry models.

关键词： charging simulation ASTROD I GEANT4 solar energetic particles

THEORETICA　LCALCULATION　OF　ATOMIC　AND　MOLECULAR　DATA

在线全文

学校读者我要写书评

暂无评论

原子与分子物理学报 1997年第2期 35-37页

作者： Pei Chunchuan purple mountain observatory Academia Sinica nanjing 210008

ＴＨＥＯＲＥＴＩＣＡＬＣＡＬＣＵＬＡＴＩＯＮＯＦＡＴＯＭＩＣＡＮＤＭＯＬＥＣＵＬＡＲＤＡＴＡＰｅｉＣｈｕｎｃｈｕａｎＰｕｒｐｌｅＭｏｕｎｔａｉｎＯｂｓｅｒｖａｔｏｒｙＡｃａｄｅｍｉａＳｉｎｉｃａＮａｎｊｉｎｇ２１０... 详细信息

ＴＨＥＯＲＥＴＩＣＡＬＣＡＬＣＵＬＡＴＩＯＮＯＦＡＴＯＭＩＣＡＮＤＭＯＬＥＣＵＬＡＲＤＡＴＡＰｅｉＣｈｕｎｃｈｕａｎＰｕｒｐｌｅＭｏｕｎｔａｉｎＯｂｓｅｒｖａｔｏｒｙＡｃａｄｅｍｉａＳｉｎｉｃａＮａｎｊｉｎｇ２１０００８ＡＢＳＴＲＡＣＴＢｙｕｓｉｎ...

关键词： Atomic and molecular data Interstellar molecules Equation of state Molecular lines observation