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A new photometric study of the triple star system EF Draconis

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Research in Astronomy and Astrophysics 2012年第4期12卷 419-432页

作者： yuan-gui Yang School of Physics and Electronic Information Huaibei Normal UniversityHuaibei 235000China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650011China

We present new charge-coupled device （CCD） photometry for the triple star EF Draconis, obtained in 2009 and 2011. Using the updated Wilson-Devinney program, the photometric solutions were deduced from two sets of light curves. The results indicate that EF Dra is an A-type W UMa binary with a contact degree of f = 46.7%（ ± 0.6%） and a third light of l 3 ■1.5%. Through analyzing the O C curve, it is found that the orbital period shows a long-time increase with a lighttime orbit. The period, semi-amplitude and eccentricity of the third body are P mod = 17.20（ ± 0.18） yr, A = 0.0039 d （ ± 0.0002 d ） and e = 0.49（ ± 0.02） respectively. This kind of tertiary companion may extract angular momentum from the central system. The orbital period of EF Dra secularly increases at a rate of dP/dt = ＋3.72（ ± 0.07） × 10 7 d yr 1 , which may be interpreted by mass transfer from the less massive to the more massive component. As period increases, the separation between components may increase, which will cause the contact degree to decrease. With mass transferring, the spin angular momentum will increase, while the orbital angular momentum will decrease. Only if the contact configuration would merge at J spin 〉1/3 J orb could this kind of deep-contact binary with period increasing, such as EF Dra, evolve into a rapidly-rotating single star.

关键词： stars (including multiple): binaries: close — stars: individual (EF Draconis)

Derivation of 2×2 Thermal Propagator Without Factorization

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Chinese Physics Letters 1998年第3期15卷 157-158页

作者： ZUO Jian gui yuan-xing Department of Mathematics Dalian University of TechnologyDalian 116023 Department of Physics Dalian University of TechnologyDalian 116023

The real time thermal propagator with 2×2 matrix structure is derived in the functional formalism of the field theory inη-ξ*** is emphasized that the trouble-shooting factorization of generating functional in the t... 详细信息

关键词： generating derivation functional

Derivation of Tilde Rules in η-ξ Spacetime

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Chinese Physics Letters 1998年第1期15卷 1-2页

作者： ZUO Jian gui yuan-xing Department of MathematicsDalian University of Technology Dalian 116023 Department of Physics Dalian University of Technology Dalian 116023

The M operation is introduced in η-ξ spacetime to derive the tilde rules in thermo field dynamics (TFD). This leads to an explanation of the tilde system in TFD as the system in region II of η-ξ spacetime.

关键词： spacetime system explanation

Four-Party Quantum Broadcast Scheme Based on Aharonov State

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Communications in Theoretical Physics 2008年第8期50卷 371-374页

作者： LI yuan ZENG gui-Hua Laboratory of Coding and Communication Security Department of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 China

In this paper,we propose a solution based on four-qubit Aharonov state to an old problem by using the property of *** proposed scheme may realize the broadcast among four participants,therefore,it makes progress to the three-party broadcast realized *** pairwise quantum channels and entangled qubits,the detection between these players also can be ***,the feasibility of the protocol and the analysis of security are illustrated.

关键词： broadcast scheme Aharonov state liar detection problem congruence

Effect of Freeze-Thaw on Water Stability of Aggregates in a Black Soil of Northeast China

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Pedosphere 2014年第2期24卷 285-290页

作者： LI gui-yuan FAN Hao-Ming College of Water Conservancy Shenyang Agricultural University

Soil aggregate stability,an important index of the physical characteristics of a soil,can provide a good indication of a soil’s erodibility,and deserves special consideration in regions with cold *** objective of this study was to study the effect of freeze-thaw on soil water-stable aggregates in the black soil region of Northeast *** of a typical black soil in the region were collected to measure water-stable aggregates after freeze-thaw under different conditions(i.e.,initial moisture contents,freezethaw cycles and freezing temperatures)by wet-sieving into eight particle size groups(>10,10–6,6–5,5–3,3–2,2–1,1–0.5,and0.5–0.25 mm).Freeze-thaw had the most effect on aggregate stability when the samples had an initial moisture content of 400 g *** water-stable aggregates of the four larger particle size groups(>5,5–3,3–2,and 2–1 mm)reached a peak stability value,but those of the two smaller particle size groups(1–0.5 and 0.5–0.25 mm)reached a minimum value when the soil moisture content was 400 g ***-stable aggregates of the four larger particle size groups decreased while those of the two smaller particle size groups increased with the increase of freeze-thaw *** temperatures fell,the water-stable aggregates of the four larger particle size groups decreased while those of the two smaller particle size groups increased.

关键词： freezing temperature moisture content particle size water-stable aggregates

TZ Lyrae:an Algol-type Eclipsing Binary with Mass Transfer

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Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 258-264页

作者： yuan-gui Yang Xin-Guo Yin Physics Department of Huaibei Coal Industry Teachers College Huaibei 235000

We present a detailed investigation of the Algol-type binary TZ Lyrae, based on 55 light minimum timings spanning 90 years. It is found that the orbital period shows a long-term increase with a cyclic variation superimposed. The rate of the secular increase is dP/dt = ＋7.18 × 10^-8d yr^-1, indicating that a mass transfer from the less massive component to the more massive one at a rate of dra = ＋2.21 × 10^-8M⊙ yr^-1. The cyclic component, with a period of P3 = 45.5 yr and an amplitude of A = 0.^d0040, may be interpreted as either the light-time effect in the presence of a third body or magnetic activity cycles in the components. Using the latest version Wilson-Devinney code, a revised photometric solution was deduced from B and V observations. The results show that TZ Lyr is an Algol-type eclipsing binary with a mass ratio of q = 0.297±0.003）. The semidetached configuration with a lobe-filling secondary suggests a mass transfer from the secondary to the primary, which is in agreement with the long-term period increase of the binary system.

关键词： stars binaries close - stars binaries eclipsing - stars individual TZ Lyrae

PS Vir:a short-period solar-like contact binary

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Research in Astronomy and Astrophysics 2018年第7期18卷 45-52页

作者： Hui-Yu yuan Hai-Feng Dai yuan-gui Yang Information College Huaibei Normal University School of Physics and Electronic Information Huaibei Normal University

We present multi-color photometric observations and a one-dimensional spectrum, acquired from March 2016 to May 2017, for the short-period eclipsing binary PS Vir, by using the 2.16-m, 85-cm and 60-cm telescopes at Xinglong station, which is administered by National Astronomical Observatories, Chinese Academy of Sciences. The spectral type was determined as G2V from the one-dimensional spectrum. The photometric solution was reduced from BVRc light curves. The results imply that PS Vir is a W-subtype contact binary with a mass ratio of q - 0.305（zk0.008） and a fill-out factor of f = 14.4（＋1.8）%. The orbital period may be undergoing a cyclic oscillation with an ampli-tude of A = 0.0027（~0.0001）d and a modulated period of 11.7（4-0.2） yr, which may result from the light-time effect due to a third body. The lower limit on mass for the assumed component is 0.12 Me. Moreover, the more massive component of PS Vir may be a bit more evolved star as determined from the mass-luminosity diagram.

关键词： binaries close-binaries eclipsing-stars individual(PS Vir)-stars

IU Cancri:a solar-type contact binary with mass transfer

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Research in Astronomy and Astrophysics 2019年第6期19卷 89-96页

作者： Hui-Yu yuan Hai-Feng Dai yuan-gui Yang Information College Huaibei Normal University Huaibei 235000 China School of Physics and Electronic Information Huaibei Normal University Huaibei 235000 China

We present new CCD photometry of the solar-type contact binary IU Cnc, which was observed from November 2017 to March 2018 with three small telescopes in China. BV light curves imply that IU Cnc is a W-type contact binary with total eclipses. The photometric solution indicates that the mass ratio and fill-out factor are q = 4.104 ± 0.004 and f = 30.2%± 0.3%, respectively. From all available light minimum times, the orbital period may increase at a rate of dP/dt =+6.93(4)× 10^-7 d yr^-1, which may result from mass transfer from the secondary component to the primary one. With mass transferring,IU Cnc may evolve from a contact configuration into a semi-detached configuration.

关键词： binaries:close-binaries eclipsing-stars individual(IU Cancri)

Discussion of Garfinkle-Horowitz-Strominger Dilaton Black Hole Entropy

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Communications in Theoretical Physics 2009年第7期52卷 189-192页

作者： WANG Chun-Yan gui yuan-Xing School of Physics and Optoelectronic Technology Dalian University of Technology Dalian 116024 China

We discuss the entropy of the Garfinkle-Horowitz-Strominger dilaton black hole by using the thin film brick-wall model, and the entropy obtained is proportional to the horizon area of the black hole confirming the Bekenstein-Hawking＇s area-entropy formula. Then, by comparing with the original brick-wall method, we find that the result obtained by the thin film method is more reasonable avoiding some drawbacks, such as little mass approximation, neglecting logarithm term, and taking the term L^3 as a contribution of the vacuum surrounding the black hole, and the physical meaning of the entropy is more clearer.

关键词： Garfinkle-Horowitz-Strominger dilaton black hole thin film brick-wall model entropy