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BL Lacertae: Hard Optical Spectrum and GeV γ-ray Emission

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Chinese Journal of Astronomy and Astrophysics 2004年第3期4卷 231-246页

作者： Shan-JieQian xi-zhenzhang T.P.Krichbaum NationalAstronomicalObservatories ChineseAcademyofSciencesBeijing100012 Max-Planck-InstitutfürRadioastronomie AufdemHügel6953121BonnGermany

The spectral energy distribution (SED) of the γ-ray flare observed inJuly 1997 in BL Lacertae is re-considered. It is pointed out that the optical observa-tions made by Webb et al. showed the associated optical flare has a hard spectrum(the average spectral index αopt～ 0.48, F_v∝v^(-α)), and the ASCA observationsmade by Tanihata et al. showed very steep spectra in the soft X-ray band (0.7-1.5 keV) (α_x～3-4). We find that the flux densities and spectral indices in both theoptical and soft X-ray bands are closely consistent with a ‘canonical' synchrotronspectrum emitted by relativistic electrons of a power-law energy distribution witha high energy cutoff, and thus the peak of the SED of the synchrotron radiation (inrepresentation of vF_v) is located in the EUV -- soft X-ray bands. Therefore, theGeV γ-ray emission observed in the July 1997 outburst may be mainly due to thesynchrotron self-Compton (SSC) process, contrasting with the current explanationsin terms of external radiation Compton (ERC) process, in which the seed photonsare mostly taken to be the UV emission from the clouds of the broad emission lineregion. We argue that the hard optical spectra observed during the γ-ray outburstmay be an important signature for the acceleration of high energy electrons (γ_e～10~4)in the γ-ray emitting region.

关键词： galaxies:compact gamma rays:observations quasars:individual:BL Lacertae

Negative PO3-implanted bionic ion transport channels for promoting Li-S battery

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Science China Chemistry 2025年

作者： Wenhuan Huang Shun Wang Xuehan Hou Yanan Zhang xingxing Zhang Yaoxiao Zhao xilang jin Huabin Zhang Fei Wang jian Zhang Key Laboratory of Chemical Additives for China National Light Industry College of Chemistry and Chemical EngineeringShaanxi University of Science and Technology School of Materials and Chemical Engineering Xi'an Technological University Chemistry Program Physical Science and Engineering Division King Abdullah University of Science and Technology State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences

Lithium-sulfur （Li-S） battery,as a promising next-generation high-energy-density battery,suffers from lithium polysulfides（LPSs） shuttle and Li dendrites *** crystalline framework-based membranes as separator can effectively absorb and restrain LPSs but without precise structural design principal exploration and mechanism ***,bio-inspired 1D oriented lithium-ion transport channels with molecular negatively charged PO3（-1） have been developed in hybrid tetrazole frameworks for promoting the transmission of Li+*** theoretical calculations and in situ spectroscopy demonstrated the higher binding energy and inhibited diffusion of LPSs in *** assembled PP@PO3Janus separator in Li-S coin cell delivered a high initial capacity of 1410.9 mAh g-1at 0.1 C and a low attenuation rate of 0.038%per cycle over 500 cycles at 5 ***,the high capacities of 862,542 and 409 mAh g-1based on high-sulfur-loading cathodes of 2.6,3.8 and 5.0 mg cm-2at0.5 C were achieved,***,the punch battery of PO3@PP separator with S-cathode of 1.2 mg cm-2has been developed for demonstrating its potentials commercial application,which displays impressive capacity of 873.4 mAh g-1with the retention of～78.9%over 50 cycles.

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Radio Observations at 232 MHz and Multifrequency Spectral Studies of the SNR HB21

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Chinese Journal of Astronomy and Astrophysics 2001年第5期1卷 443-452页

作者： xi－zhenzhang L.A.Higgs 等 NationalAstronomicalObservatories ChineseAcademyofSciencesBeijing100012 DominionRadioAstrophysicalOb

Radio observational results at 232 MHz and multifrequency studies of the supernova remnant (SNR) HB21 are presented. Its integrated flux density at 232 MHz is about 390 + 30 Jy. Both the integrated spectral index and the spatial variations of spectral index of the remnant were calculated by combining the new map at 232 MHz with previously published maps made at 408, 1420, 2695, and 4750 MHz. The SNR has an integrated spectral index of about a = -0.43 (Sv Vα) between 232 and 4750 MHz. In general the spectral index varies from -0.5 in southeast and west regions of the remnant to -0.3 in the central region and near the northwest edge. The new data of 232 MHz reveal that there is interaction between the remnant and the surrounding gas along the east edge of the remnant which causes the spectrum flattening at low frequency, while the very good agreement between the structure of X-ray emission and the central flat spectrum area suggests that the existence of thermal emission is the reason of spectrum flattening in the area.

关键词： ISM: supernova remnants - ISM: structure

Periodic Variations of the Jet Flow Lorentz Factor in 3C 273

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Chinese Journal of Astronomy and Astrophysics 2001年第3期1卷 236-244页

作者： SHAN－JieQian xi－zhenzhang 等 Max－Planck－InstitutfuerRadioastronomie AufdemHuegel69D－53121BonnGermany BeijingAstronomicalObservat

C 273 has been observed with VLBI for more than 30 years. The entire data have shown that the position angle of the superluminal knots ejected from the core varies periodically with a period of ~15 years. Moreover, their apparent velocity observed during the period 1963 -- 1997 has systematically decreased by a factor of 2. These remarkable properties are explained in terms of a precessing jet model, in which the ejection Lorentz factor of the superluminal knots has been decreasing during the last thirty years and has superposed on it a short-term (~5 year) oscillation. The periodic variations derived by the model-fitting are compared with the variations in the optical flux density. Binary black hole models are briefly discussed to show possible relations of the observed periods to the periods involved in a binary system (orbital motion, spin of black hole, accretion-disk rotation and Newtonian-driven precession etc.).

关键词： Galaxies: jets - quasars: individual: 3C273 - Galaxies: nuclei - Radio Continuum: galaxies - Radiation mechanisms: nonthermal

An Intrinsic Model for the Polarization Position Angle Swing Observed in QSO 1150+812

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Chinese Journal of Astronomy and Astrophysics 2004年第1期4卷 37-50页

作者： Shan-JieQian xi-zhenzhang NationalAstronomicalObservatories ChineseAcademyofSciencesBeijing100012

The rapid polarization position angle swing of ~ 180° observed in QSO 1150+812 at 2cm by Kochenov and Gabuzda is quite a regular event. One interesting property of the event is that, during the time of the swing the polarized flux density remained almost constant. We suggest that such an event can be explained in terms of a relativistic thin shock propagating through a uniform helical magnetic field, giving rise to relativistic aberration effects as the transverse field component rotates. The model may also be applicable to other similar events in which variations in polarization are not accompanied by variations in total flux density.

关键词： radio continuum: galaxies polarization quasars: individual: QSO 1150+812

Theoretical and experimental study of surface texturing with laser machining

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Advances in Manufacturing 2021年第4期9卷 538-557页

作者： Ya-Zhou Mao jian-xi Yang jin-Chen Ji School of Mechatronics Engineering Henan University of Science and TechnologyLuoyang 471003HenanPeople’s Republic of China School of Mechanical and Mechatronic Engineering University of Technology SydneySydneyNSW 2007Australia

To explore the forming process and mechanism of the surface texture of laser micropits,this paper presents the thermal model of laser machining based on the Neumann boundary conditions and an investigation on the effects of various parameters on the *** surface profile and quality of the formed micropits were analyzed using NanoFocus 3D equipment through a design of experiment(DOE).The results showed that more intense melting and splashing occurred with higher power density and narrower pulse ***,the compressive stress is an important indicator of the damage effects,and the circumferential thermal stress is the primary factor influencing the diameter *** the process of laser machining,not only did oxides such as CuO and ZnO generate,the energy distribution also tended to decrease gradually from region#1 to region#3 based on an energy dispersive spectrometer(EDS)*** factors significantly affecting the surface quality of the micropit surface texture are the energy and pulse *** relationship between taper angle and energy is appropriately *** on the formation process and mechanism of the surface texture of laser micropits provides important guidance for precision machining.

关键词： Laser machining Thermal stress damage Surface texturing Design of experiment(DOE) Micropit

On the Spectral Index-Flux Density Relation for Large Samples of Radio Sources

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Chinese Journal of Astronomy and Astrophysics 2003年第4期3卷 347-358页

作者： xi-zhenzhang W.Reich P.Reich R.Wielebinski NationalAstronomicalObservatories ChineseAcademyofSciencesBeijing100012 Max-Planck-InstitutfuerRadioastronomie AufdemHuegel69D-53121BonnGermany

We present new statistical results on the spectral index-flux density relation for large samples of radio sources using archival data of the most sensitive surveys, such as 6C, Miyun, WENSS, B3, NVSS, GB87. Instrumental selection effects and the completeness of the catalogs are discussed. Based on the spectral indices calculated for about 200 000 sources from the WENSS (327 MHz) and NVSS (1.4 GHz) catalogs, we obtained (1) The median spectral index increases from amed --0.9 toαmed --0.8 (Svαvα), while S327 flux densities decrease from 0.1 Jy down to 25mJy. The median spectral indices nearly show no variation within the error bars when the flux density is larger than 0.1 Jy. (2) A dependence of the fraction of ultra-steep spectrum sources (USS, -1.5 <α<-1.0), steep spectrum sources (SSS, -1.0 <α< -0.5) and flat spectrum sources (FSS, -0.5≤α≤0.0) is partly responsible for the spectral flattening. Another contribution to the spectral flattening comes from the variation of αmed of steep spectrum sources (α<-0.5) themselves which increases with decreasing flux densities. (3) The spectral flattening for faint sources (down to S327- 20mJy) with steep spectra (α< -0.5) suggests that amed is correlated with luminosity rather than redshift according to the Condon' model. (4) A strong spectral selection effect occurs when spectral indices are calculated from samples with a large frequency separation.

关键词： radio continuum: general-methods: statistical - cosmology

Preparation and Performance of HGM/PPENK-based High Temperature-resistant Thermal Insulating Coatings

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Chinese Journal of Polymer Science 2021年第6期39卷 770-778,I0008页

作者： Lei Song Li-Shuai Zong jin-Yan Wang xi-Gao jian State Key Laboratory of Fine Chemicals Department of Polymer Science and MaterialsSchool of Chemical EngineeringDalian University of TechnologyDalian 116024China

Novel high temperature-resistant coatings with high mechanical strength and thermal-insulating performance were prepared with poly(ether nitrile ketone)(PPENK)resin as matrix and hollow glass microspheres(HGMs)as thermal-insulating *** corresponding mechanical and thermal-insulating study indicated that the mechanical properties of the coatings decreased with the increase of HGM content,and were improved after surface modification of HGM by KH570 resulting in enhancement of interaction between HGM and PPENK *** thermal conductivity of HGM/PPENK thermal-insulating coating decreased with the increase of HGM content and coating thickness,along with the decrease of the true *** also showed slight increase trend due to HGMs surface *** HGM/PPENK coating filled with modified HGMs showed better thermal resistance than that of unmodified HGM/PPENK *** thermal decomposition temperature at 5%weight loss of the coating containing modified HGMs was 10°C lower than that of pure PPENK,and 40°C higher than that of neat HGM/PPENK *** coating exhibited commendable appearance after 400°C for 30 *** merits of HGM/PPENK-based thermal coatings obviously demonstrated promising prospect in thermal protection fields.

关键词： Coatings Temperature-resistant HGM/PPENK Thermal conductivity Mechanical properties

A novel epoxy methacrylate resin containing phthalazinone moiety for UV coatings

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Chinese Chemical Letters 2007年第5期18卷 598-600页

作者： Yan Kou jin Yan Wang xi Gao jian Department of Polymer Science and Materials Dalian University of TechnologyLiaoning High Performance Resin Engineering Research Center Dalian 116012 China

A novel ohthalazinone modified epoxy acrylate resin for the high temperature resistant ultravioet （UV） curable *** *** methacrylated epoxy resins obtained were utilized to UV radiation curing by taking 2.5% （wt%） of photoinitiator in combination with 20% （wt%） of diluent, and generated the interpenetraring polymer networks. The cured film had good thermal and chemical stability.

关键词： UV curable Epoxy acrylate Phthalazione Crosslinking