检索结果-南通市图书馆

Long-term photometric behavior of the eclipsing Z Cam-type dwarf nova AY Psc

Research in Astronomy and Astrophysics 2017年第6期17卷 67-76页

作者： zhong-tao han Sheng-Bang Qian Irina Voloshina Li-Ying Zhu Yunnan Observatories Chinese Academy of Sciences Kunming 650216 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650216 China University of Chinese Academy of Sciences Beijing 100049 China Sternberg Astronomical Institute Moscow State University Universitetskij prospect 13 Moscow 119992 Russia

New eclipse timings of the Z Cam-type dwarf nova AY Psc were measured and the orbital ephemeris was revised. In addition, based on long-term AAVSO data, the outburst behaviors were also explored. Our analysis suggests that normal outbursts are quasi-periodic, with an amplitude of 2.5（4-0.1） mag and a period of - 18.3（4-0.7） d. The amplitude vs. recurrence-time relation ofAY Psc is discussed, and we conclude that this relation may represent general properties of dwarf nova outbursts. The observed standstill ends with an outburst, which is inconsistent with the general picture of Z Cam- type stars. This unusual behavior was considered to be related to mass-transfer outbursts. Moreover, the average luminosity Is brighter during standstills than during outburst cycles. The changes in brightness mark variations in M2 due to the fact that the disk of AY Psc is nearly steady state.M2 value was limited to the range from 6.35 × 10-9 to 1.18 × 10-8 M yr-1. More detailed examination shows that there are a few small outbursts present during standstills. These events with amplitudes of - 0.5 - 0.9 mag are very similar to the stunted outbursts reported in some nova-like cataclysmic variables. We discussed several possible mechanisms and suggested that the most reasonable mechanism for these stunted outbursts is a changing mass-transfer rate.

关键词： binaries close - stars cataclysmic variables - stars individual (AY Psc)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Physical properties of γ Doradus pulsating stars and their relationship with long-period δ Scuti variables

引用

Research in Astronomy and Astrophysics 2019年第1期19卷 1-20页

作者： Sheng-Bang Qian Lin-Jia Li Jia-Jia He Jia Zhang Li-Ying Zhu zhong-tao han Yunnan Observatories Chinese Academy of Sciences Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Center for Astronomical Mega-Science Chinese Academy of Sciences University of Chinese Academy of Sciences

We present LAMOST data on 168 γ Doradus(γ Dor) pulsating stars including stellar atmospheric parameters of 137 variables and spectral types for all of the samples. The distributions of period(P), temperature(T), gravitational acceleration(log(g)) and metallicity [Fe/H] are shown. It is found that most γ Dor variables are main-sequence stars with early F spectral types and temperatures from 6880 K to7280 K. They are slightly more metal poor than the Sun with a metallicity range from-0.4 to 0. On the H-R and log g-T diagrams, both the γ Dor and δ Scuti(δ Sct) stars occupy in the same region and some are beyond the borders predicted by current stellar pulsation theories. It is discovered that the physical properties of γ Dor stars are similar to those of long-period δ Sct(P > 0.3 d) stars. The stellar atmospheric parameters are all correlated with the pulsation period for short-period δ Sct variables(P < 0.3 d), but there are no such relations for γ Dor or long-period δ Sct stars. These results reveal that γ Dor and long-period δ Sct are the same group of pulsating stars and they are different from short-period δ Sct variables. Meanwhile, 33γ Dor stars are identified as candidates of binary or multiple systems.

关键词： stars:fundamental parameters stars:oscillations stars:binaries:spectroscopic stars:variables:other

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Photometric analysis of the eclipsing polar MN Hya

引用

Research in Astronomy and Astrophysics 2018年第7期18卷 11-20页

作者： Qi-Shan Wang Sheng-Bang Qian zhong-tao han Miloslav Zejda Eduardo Fernandez-Lajus Li-Ying Zhu Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming650216China University of Chinese Academy of Sciences Beijing 100049China Department of Theoretical Physics and Astrophysics Masaryk UniversityKotlfirgkfi 2Bmo 611 37Czech Republic Facultad de Ciencias Astron6micas y Geoffsicas Universidad Nacional de La PlataPaseo del Bosque s/n1900La PlataPcia.Bs.As.Argentina Instituto de Astroffsica de La Plata(CCT La plata-CONICET/UNLP) Argentina

As an eclipsing polar with a 3.39 h orbital period, MN Hya was going through a state change when we observed it during 2009-2016. Ten new mid-eclipse times, along with others obtained from literature, allow us to give a new ephemeris. The residuals of a linear fit show that period decreased during the phase of state change, which means angular momentum was lost during this phase. The associated X-ray observation indicates the mass accretion rate was about 3.6 x 10^-9 Mo yr^-1. The period decrease indicates that at least 60% of mass being transferred from the secondary was lost, maybe in the form of spherically symmetric stellar wind. In the high state, the data show the intensity of flickering reduced when the system had a higher accretion rate, and that flickering sticks out with a primary timescale of about 2 min, which implies the position of the threading point was about 30 white dwarf radii above its surface. The trend of light curves for the system in its high state follows that of the low state for a large fraction of the phase interval from phase 0 to phase 0.4 since, starting at phase 0.4, the cyclotron feature is visible, and the primary intensity hump of the light curves near phase 0.7 when the system is in the high state did not appear on the curve when it was in the low state. Those facts contradict predictions of the two-pole model.

关键词： techniques photometric-stars cataclysmic variables eclipsing polars-stars individ-ual (MN Hya)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Physical parameters and orbital period variation of a newly discovered cataclysmic variable GSC 4560-02157

引用

Research in Astronomy and Astrophysics 2016年第10期16卷 55-62页

作者： zhong-tao han Sheng-Bang Qian Irina Voloshina Vladimir G. Metlov Li-Ying Zhu Lin-Jia Li Yunnan Observatories Chinese Academy of Sciences Kunming 650216 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650216China University of Chinese Academy of Sciences Beijing 100049 China Sternberg Astronomical Institute Moscow State University Universitetskij prospect 13 Moscow 119992 Russia

GSC 4560-02157 is a new eclipsing cataclysmic variable with an orbital period of 0.265359 days. By using the published V- and R-band data together with our observations, we discovered that the O - C curve of GSC 4560-02157 may show a cyclic variation with a period of 3.51 years and an amplitude of 1.40 min. If this variation is caused by a light travel-time effect via the existence of a third body, then its mass can be derived as M3 sin i1≈ 91.08 Mjup, and it should be a low-mass star. In addition, several physical parameters were measured. The color of the secondary star was determined to be V - R = 0.77（±0.03） which corresponds to a spectral type of K2-3. The secondary star＇s mass was estimated as M2 = 0.73（±0.02） Mo by combing the derived V - R value around phase 0 with the assumption that it obeys the mass-luminosity relation for main sequence stars. This mass is consistent with the mass-period relation for CV donor stars. For the white dwarf, the eclipse durations and contacts of the white dwarf yield an upper limit on the white dwarf＇s radius corresponding to a lower limit on mass of M1 ≈ 0.501 M⊙. The overestimated radius and previously published spectral data indicate that the boundary layer may have a very high temperature.

关键词： techniques: photometric -- stars: binaries: cataclysmic variables -- stars: individual:GSC 4560-02157

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

More than two hundred and fifty thousand spectroscopic binary or variable star candidates discovered by LAMOST

引用

Research in Astronomy and Astrophysics 2019年第5期19卷 15-26页

作者： Sheng-Bang Qian Xiang-Dong Shi Li-Ying Zhu Lin-Jia Li Jia Zhang Er-Gang Zhao zhong-tao han Xiao Zhou Xiao-Hui Fang Wen-Ping Liao Yunnan Observatories Chinese Academy of Sciences Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Center for Astronomical Mega-Science Chinese Academy of Sciences University of Chinese Academy of Sciences

About 786.4 thousand stars were observed by LAMOST twice or more during the first stage of its spectroscopic survey. The radial velocity differences for about 256 thousand targets are larger than10 km s^(-1) and they are possible spectroscopic binary or variable candidates(SBVCs). It is shown that most SBVCs are slightly metal poorer than the Sun. There are two peaks in the temperature distribution of SBVCs around 5760 K and 4870 K, while there are three peaks in the distribution of the gravitational acceleration at 2.461, 4.171 and 4.621 cm s^(-2). The locations of SBVCs on the [Fe/H]-T, [Fe/H]-log g, log g-T and H-R diagrams are investigated. It is found that the detected SBVCs could be classified into four groups. The first group has higher log g～4.621 and lower T ～ 4870 K which are mainly cool red dwarf binaries. The second group of SBVCs has logg around 4.171 cm s^(-2) that includes binaries and pulsating stars such as δSet and γ Dor variables. The gravitational accelerations of the third group of SBVCs are higher and some of them are below the zero-age main sequence. They may be contact binaries in which the primary components are losing energy to the secondaries in the common envelopes and are at a special stellar evolutionary *** last group is composed of giants or supergiants with log g around 2.461 cm s^(-2) that may be evolved pulsating stars. One target(C134624.29+333921.2) is confirmed as an eclipsing binary with a period of 0.65 days. A preliminary analysis suggests that it is a detached binary with a mass ratio of 0.46. The primary fills its critical Roche lobe by about 89%, indicating that mass transfer will occur between the two components.

关键词： stars fundamental parameters-stars binaries spectroscopic-stars:oscillations-stars:binaries eclipsing-stars variables other

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Transumbilical single-port laparoscopic cholecystectomy： a case report

引用

Chinese Medical Journal 2008年第23期121卷 2463-2464页

作者： GUO Wei ZhanG zhong-tao han Wei LI Jian-she JIN Lan LIU Jun ZHAO Xiao-mu WANG Yu Department of General Surgery Beijing Friendship Hospital Capital Medical University Beijing 100050 China

Recently, scarless surgery has become a widely used surgical technique, which has made considerable progress owing to extensive animal model studies and clinical trials. Here, we report the first case of transumbilica... 详细信息

关键词： laparoscopic cholecystectomy clinical trials mainland China animal model

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

圆中空夹层钢管混凝土柱力学性能研究

引用

土木工程学报 2004年第10期37卷 41-51页

作者：陶忠韩林海黄宏福州大学

分别进行了十四个轴心受压构件和十二个偏心受压构件的试验研究 ,二种构件的试验参数分别为钢管径厚比和空心率 ,构件长细比和偏心率。在确定组成圆中空夹层钢管混凝土的钢材和核心混凝土应力 -应变关系模型的基础上 ,利用数值解法对圆... 详细信息

分别进行了十四个轴心受压构件和十二个偏心受压构件的试验研究 ,二种构件的试验参数分别为钢管径厚比和空心率 ,构件长细比和偏心率。在确定组成圆中空夹层钢管混凝土的钢材和核心混凝土应力 -应变关系模型的基础上 ,利用数值解法对圆中空夹层钢管混凝土轴压和压弯构件的荷载 -变形关系进行了全过程分析 ,分析结果与试验结果吻合良好。最后在参数分析的基础上 ,提供了圆中空夹层钢管混凝土轴压和压弯构件承载力实用验算方法。

关键词：中空夹层钢管混凝土轴压偏压荷载-变形关系承载力

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

方中空夹层钢管混凝土偏心受压柱力学性能的研究

引用

土木工程学报 2003年第2期36卷 33-40,51页

作者：陶忠韩林海黄宏福州大学

以长细比和偏心率为变化参数 ,共进行了十二个方中空夹层钢管混凝土偏心受压构件的试验研究。在确定组成方中空夹层钢管混凝土的钢材和核心混凝土应力应变关系模型的基础上 ,利用数值解法对方中空夹层钢管混凝土压弯构件的荷载变形... 详细信息

以长细比和偏心率为变化参数 ,共进行了十二个方中空夹层钢管混凝土偏心受压构件的试验研究。在确定组成方中空夹层钢管混凝土的钢材和核心混凝土应力应变关系模型的基础上 ,利用数值解法对方中空夹层钢管混凝土压弯构件的荷载变形全过程关系进行了分析 ,理论分析结果与试验结果吻合较好。最后。

关键词：方中空夹层钢管混凝土柱偏心率荷载-位移曲线承载能力偏心受压柱力学性能

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

加劲薄壁钢管混凝土柱的试验性能

引用

钢结构(中英文) 2008年第4期 83-84页

作者： zhong tao, Lin-Hai han and Dong-Ye Wang

对加劲薄壁钢管混凝土柱的结构性能进行试验研究。通过在钢管内表面焊接纵向加劲肋实现加强的作用。同时对12个不带加劲肋的钢管混凝土柱进行试验,部分柱的填充混凝土中加有钢纤维。试验结果表明,加劲肋可以有效延迟钢管局部屈曲现象的... 详细信息

对加劲薄壁钢管混凝土柱的结构性能进行试验研究。通过在钢管内表面焊接纵向加劲肋实现加强的作用。同时对12个不带加劲肋的钢管混凝土柱进行试验,部分柱的填充混凝土中加有钢纤维。试验结果表明,加劲肋可以有效延迟钢管局部屈曲现象的出现。当加劲构件达到最大承载量时钢板才出现屈曲,所以相比普通钢管混凝土,加劲钢管混凝土具有更高的适用性。

关键词：钢管混凝土(CFST) 薄壁柱局部屈曲加劲肋钢纤维混凝土(SFRC) 强度延性

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Multi boron-doping effects in hard carbon toward enhanced sodium ion storage

引用

Journal of Energy Chemistry 2025年第1期100卷 730-738页

作者： Peng Zheng Wang Zhou Ying Mo Biao Zheng Miaomiao han Qin zhong Wenwen Yang Peng Gao Lezhi Yang Jilei Liu College of Materials Science and Engineering Hunan Joint International Laboratory of Advanced Materials and Technology for Clean Energy Hunan Province Key Laboratory for Advanced Carbon Materials and Applied Technology Hunan University Greater Bay Area Institute for Innovation Hunan University Changsha Research Institute of Mining & Metallurgy Co. LTD.

Hard carbon （HC） has been considered as promising anode material for sodium-ion batteries （SIBs）.The optimization of hard carbon’s microstructure and solid electrolyte interface （SEI） property are demonstrated effective in enhancing the Na+storage capability,however,a one-step regulation strategy to achieve simultaneous multi-scale structures optimization is highly ***,we have systematically investigated the effects of boron doping on hard carbon’s microstructure and interface chemistry.A variety of structure characterizations show that appropriate amount of boron doping can increase the size of closed pores via rearrangement of carbon layers with improved graphitization degree,which provides more Na+storage ***-situ Fourier transform infrared spectroscopy/electrochemical impedance spectroscopy （FTIR/EIS） and X-ray photoelectron spectroscopy （XPS） analysis demonstrate the presence of more BC3and less B–C–O structures that result in enhanced ion diffusion kinetics and the formation of inorganic rich and robust SEI,which leads to facilitated charge transfer and excellent rate *** a result,the hard carbon anode with optimized boron doping content exhibits enhanced rate and cycling *** general,this work unravels the critical role of boron doping in optimizing the pore structure,interface chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced Na+storage performance.

关键词： X ray photoelectron spectroscopy

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：