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Calibrating the HXMT collimators using diffuse illumination

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 36-39页

作者： HAN Dong1,JIN YongJie1,WU Mei2.& ZHANG Zhi1 1 Department of Engineering Physics & Center for astrophysics,Tsinghua University,beijing 100084,{2. 2.key laboratory of particle astrophysics,institute of high energy Physics,chinese academy of sciences,beijing 100049,{2. 1. Department of Engineering Physics & Center for astrophysics Tsinghua University Beijing 100084 China 2. key laboratory of {2. astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

We propose a new method to calibrate the HXMT collimators by measuring the optical point spread function(PSF) of the hard X-ray modulation telescope(HXMT).The light transmission of the collimator at different viewing angles with a camera and a diffuse backlight placed behind the collimator is *** method is much easier to accomplish than measuring the PSF with a parallel optical *** experimental results are very consistent with the *** PSF of the collimator of the high energy X-ray telescope on HXMT is found to be in good agreement with the design,with accuracy better than 1 arcmin.

关键词： HXMT collimator point spread function Monte Carlo simulation diffuse illumination

Observation constraints of the hard X-ray modulation telescope HXMT

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 31-35页

作者： LU Yu1,2.ZHANG WenZhao3,QU JinLu1,SONG LiMing1,GAO Jian3,ZHANG HongMei4 & OU Ge4 1 key laboratory of {2. astrophysics,institute of high energy Physics,chinese academy of sciences,beijing 100049,china 2.Graduate University of chinese academy of sciences,beijing 100049,china 3 Department of Astronomy,beijing Normal University,beijing 100875,china 4 Computing Center,institute of high energy Physics,chinese academy of sciences,beijing 100049,china 1. key laboratory of {2. astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China 2. Graduate University of chinese academy of sciences Beijing 100049 China 3. Department of Astronomy Beijing Normal University Beijing 100875 China 4. Computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

The hard X-ray modulation telescope HXMT is a low orbit X-ray space telescope whose main science goals are to accomplish a hard X-ray all sky survey and to study timing and spectral characteristics of X-ray *** has three kinds of science instruments:the high energy X-ray detector(HE),the medium energy X-ray detector(ME) and the low energy X-ray detector(LE).The observation schedule of HXMT is a key to achieving the science goal of HXMT,and the analysis of the observation constraints is one of the first tasks in making the observation *** paper analyzes how the observation constraints influence the sky visibility and the visible time distribution of X-ray sources and discusses the schedule strategy with regard to the observation constraints.

关键词： HXMT observation constraints sky visibility

Exploration of combined adjustment laws about IGV,stator and rotational speed in off-design conditions in an axial compressor

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中国科学：技术科学英文版 2010年第4期53卷 969-975页

作者： HU YanMing1,2.& NIE ChaoQun1 1 key laboratory of Advanced {2. and Power Technology,institute of Engineeting Thermophysics,chinese academy of Science,beijing 100190,china 2.Graduate School of chinese academy of sciences,beijing 100190,china 1. key laboratory of Advanced {2. and Power Technology Institute of Engineeting Thermophysics Chinese Academy of Science Beijing 100190 China2. Graduate School of Chinese Academy of Sciences Beijing 100190 China

Experimental investigations are performed in a three-stage low-speed axial compressor with variable inlet guide vanes(IGV) and adjustable *** characteristics of the compressor,especially the efficiency and stall margin,are analyzed in design and off-design operation conditions by adjusting stagger angles of IGV and stators as well as changing the rotational *** experimental results show that the off-design performance of the multistage axial compressor is improved by restaggering of IGV and stators related to rotational *** the background of engineering applications,digital signal processing(DSP) technique is used to realize online adjustment of stagger angles according to the corresponding relations between incidence angles of rotor and rotational speed.

关键词： axial compressor IGV surge DSP techniques off-design

Research of the Gas-solid Flow Character Based on the DEM Method

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Journal of Thermal Science 2011年第6期20卷 521-526页

作者： Xueyao Wang and Yunhan Xiao Research Center for Clean energy and Power,chinese academy of sciences {2. laboratory of Advanced energy and Power,chinese academy of sciences (institute of Engineering Thermophysics),beijing,100190,china Research Center for Clean energy and Power Chinese Academy of Sciences Beijing China key laboratory of Advanced {2. and Power Chinese Academy of Sciences (Institute of Engineering Thermophysics) Beijing China

Numerical simulation of gas-solid flow behaviors in a rectangular fluidized bed is carried out three dimensionally by the discrete element method (DEM).Euler method and Lagrange method are employed to deal with the gas phase and solid phase *** collided force among particles,striking force between particle and wall,drag force,gravity,Magnus lift force and Saffman lift force are considered when establishing the mathematic ***-sphere model is used to describe the collision of *** addition,the Euler method is also used for modeling the solid phase to compare with the results of *** flow patterns,particle mean velocities,particles' diffusion and pressure drop of the bed under typical operating conditions are *** results show that the DEM method can describe the detailed information among particles,while the Euler-Euler method cannot capture the micro-scale *** matter which method is used,the diffusion of particles increases with the increase of gas *** the gathering and crushing of particles cannot be simulated,so the energy loss of particles' collision cannot be calculated and the diffusion by using the Euler-Euler method is *** addition,it is shown by DEM method,with strengthening of the carrying capacity,more and more particles can be schlepped upward and the dense suspension upflow pattern can be ***,the results given by the Euler-Euler method are not consistent with the real situation.

关键词： DEM gas-solid flow numerical simulation

GRB 09042.:Marking the death of a massive star at z=8.2

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 64-68页

作者： LIN Lin1,LIANG EnWei2.& ZHANG ShuangNan3 1 Department of Physics and Center for astrophysics,Tsinghua University,beijing 100084,{2. 2.Department of Physics,Guangxi University,Nanning 530004,{2. 3 key laboratory of particle astrophysics,institute of high energy Physics,chinese academy of sciences,{12.,{2. Guangxi Univ Dept Phys Nanning 530004 Peoples R China Tsinghua Univ Dept Phys Beijing 100084 Peoples R China Tsinghua Univ Ctr Astrophys Beijing 100084 Peoples R China chinese Acad Sci Inst High Energy Phys Key Lab Particle Astrophys Beijing 100049 Peoples R China

GRB 09042. is the new high-z record holder of Gamma-ray bursts(GRBs) with *** present a detailed analysis of both the spectral and temporal features of GRB 09042. observed with Swift/BAT and Fermi/*** find that the T90 observed with BAT in the 15-150 keV band is 13.2.s,corresponding to-1.4 s at z=*** once again gives rise to the issue of whether the progenitors of high-z GRBs are massive stars or mergers since the discovery of GRB 080913 at z=*** comparison with the T90 distribution in the burst frame of the current redshift-known GRB sample,we find that it is marginally grouped into the long group(Type II GRBs).The spectrum observed with both BAT and GBM is well fitted by a power-law with exponential cutoff,which yields an Ep=(50.4±7.0) *** event satisfies the Amati-relation well for Type II GRBs within their 3σ uncertainty *** results indicate that this event would be produced by the death of a massive *** on the Amati-relation,we derive its distance modulus,which follows the Hubble diagram of the concordance cosmology model at a redshift of-8.2.

关键词： gamma-ray bursts high energy phenomenon cosmology

Effects of cosmological constant on motion of UHECR particles

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Science china(Physics,Mechanics & Astronomy) 2005年第1期48卷 44-56页

作者： CHEN Shaoxia & CHANG Zhe institute of high {2. Physics, chinese academy of sciences, beijing 100039, china Graduate School of chinese academy of sciences, beijing 100039, china institute of high {2. Physics Chinese Academy of Sciences Beijing 100039 China Graduate School Chinese Academy of Sciences Beijing 100039 China

Recent astronomical observations manifest that about two-thirds of the whole energy in the Universe is contributed by a small positive cosmological constant A (> 0). Then, an asymptotically de Sitter spacetime is premised naturally. However, physics in the de Sitter spacetime is very different from that in the Minkowski spacetime. As the first step, a covariant formalism of the kinematics in the de Sitter spacetime is presented here. By solving exactly the equations of motion for a field, we obtain the dispersion relation of a free particle. It is noticed that the dispersion relation is dependent on the degree of freedom of angular momentum of the particle. We show the threshold anomaly of the ultra high energy cosmic ray disappears naturally in the framework of the de Sitter kinematics.

关键词： ultrahigh energy cosmic ray, cosmological constant, curved spacetime.

The time lag spectrum of Cir X-1 on its normal branch

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 60-63页

作者： QU JinLu1,LU Yu1,2.DING GuoQiang3,ZHANG Fan1,LEI YaJuan1 & LI ZhiBing1 1 key laboratory for {2. astrophysics,institute of high energy Physics,chinese academy of sciences,beijing 100049,china 2.Graduate University of chinese academy of sciences,beijing 100049,china 3 Urumqi Observatory,NAOC Urumqi 830011,china 1. key laboratory for {2. astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Urumqi Observatory NAOC Urumqi 830011 China

In the radiation-hydrodynamics model,the time lag and fractional root-mean-squared(rms) amplitude as a function of emitted photon energy should show a minimum on the normal branch *** has been seen in the Z-sources Cyg X-2.and GX ***,using the observations from the Rossi X-ray Timing Explorer(RXTE),we study the energy dependence of normal branch QPOs in the peculiar Z-source Cir *** discuss the results in the context of radiation-hydrodynamics and the Comptonization model.

关键词： Cir X-1 temporal variability QPO time lag

Study on the atmospheric photochemical reaction of CF_3 radicals using ultraviolet photoelectron and photoionization mass spectrometer

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Science china Chemistry 2008年第4期51卷 316-321页

作者： YAO Li1,2. DU Lin1,2. YIN Shi1,2.& GE MaoFa1 1 beijing National laboratory for Molecular {2. (BNLMS), State key laboratory for Structural Chemistry of Unstable and Stable Species, institute of Chemistry, chinese academy of sciences, beijing 100080, china 2.Graduate University of chinese academy of sciences, beijing 100080, china 1. beijing National laboratory for Molecular {2. (BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China 2. Graduate University of chinese academy of sciences Beijing 100080 China

A study of the atmospheric photochemical reaction of CF3 radical with CO and O2.was performed by using a homemade ultraviolet photoelectron spectrometer-photoionization mass spectrometer (PES- PIMS). The electronic structures and mechanism of ionization and dissociation of CF3OC(O)OOC(O)- OCF3 were investigated. It was indicated that the two bands on the photoelectron spectrum of CF3OC(O)OOC(O)OCF3 are the result of ionization of an electron from a lone pair of oxygen and a fluo- rine lone pair of CF3 group. The outermost electrons reside in the oxygen lone pair. The experimental and theoretical first vertical ionization energy is 13.2. and 13.178 eV, respectively, with the PES and OVGF method. They are in good agreement. The photo ionization and dissociation processes were discussed with the help of theoretical calculations and PES-PIMS experiment. After ionization, the parent ions prefer the dissociation of the C-O bond and giving the fragments CF3OCO+ and CF3+. It demonstrated that the ultraviolet photoelectron and photoionization mass spectrometer could be ap- plied widely in the study of atmospheric photochemical reaction.

关键词： photochemical reaction CF3 radical ultraviolet photoelectron and photoionization mass spectroscopy transient species

Unsteady Numerical Simulation of Hot Streak/Blades Interaction and Film Cooling

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Journal of Thermal Science 2010年第5期19卷 402-409页

作者： Weilin Yi,Lucheng Ji and Yunhan Xiao Research Center for energy and Power,chinese academy of sciences,{2.,china key laboratory of Advanced energy and Power,chinese academy of sciences,(institute of Engineering Thermophysics),{2.,china P.O.Box 2.06,{2. 100190,china Research Center for energy and Power Chinese Academy of Sciences Beijing China key laboratory of Advanced {2. and Power Chinese Academy of Sciences (Institute of Engineering Thermophysics) Beijing China beijing China

Deeply research on management and application of hot streak is an important way to breakthrough technique obstacle of aero engine hot *** method is a useful instrument to investigate the correlative *** the paper developed independently three dimensional unsteady parallel computational code-MpiTurbo based on Fortran 90 and MPI at Linux operating *** unsteady numerical simulation was carried out to investigate impacts of the factors,which included circumferential locations of hot streak and clocking positions of blade rows,on the thermal environment of a 1+1 counter-rotating *** results clearly indicated that clocking positions of hot streak/blade row and blade row/blade row had great influence on the time-averaged temperature distribution of the third blade ***,it can be effective for improving thermal environment of turbine to optimize blade parameters and clocking *** film cooling layout was designed by the repetitious steady simulation based on source term *** the flow structure detail was given by the unsteady simulation.

关键词： hot streak turbine parallel computation film cooling