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基于复杂柴油机机体特征的铸造工艺设计
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作者 汪朝志 黄鹏 +1 位作者 杨刚 尹管彬 《铸造》 CAS 2024年第9期1298-1303,共6页
为了提高V型与L型系列复杂柴油机机体柔性化制造的工艺设计效率和铸件生产质量,以典型的V型J320机体、V16机体及典型的L型K19机体、ZTD100机体为研究对象,对比研究了V型系列与L型系列复杂柴油机机体的个性特征。研究发现,两类柴油机机... 为了提高V型与L型系列复杂柴油机机体柔性化制造的工艺设计效率和铸件生产质量,以典型的V型J320机体、V16机体及典型的L型K19机体、ZTD100机体为研究对象,对比研究了V型系列与L型系列复杂柴油机机体的个性特征。研究发现,两类柴油机机体在气缸排列与气缸盖数量、缸孔夹角与缸孔数量、壁连接与转角过渡等方面均有明显不同,导致工艺设计时的浇注系统类型和浇注位置放置方式等方面也存在差异。基于V型系列和L型系列复杂柴油机机体的个性化特征进行机体的铸造工艺设计,提高了机体整体铸造的工艺出品率和产品合格率。 展开更多
关键词 复杂柴油机机体 V型机体 L型机体 个性特征 铸造工艺设计
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BSN:Photometric Light Curve Analysis of Two Contact Binary Systems LS Del and V997 Cyg
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作者 Atila Poro Mehmet Tanriver +9 位作者 Elham Sarvari Shayan Zavvarei Hossein Azarara Laurent Corp Sabrina Baudart Asma Ababafi Nazanin Kahali Poor Fariba Zare Ahmet Bulut Ahmet Keskin 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第4期192-213,共22页
The light curve analyses and orbital period variations for two contact binary stars,LS Del and V997 Cyg,are presented in this work which was conducted in the frame of the Binary Systems of South and North project Grou... The light curve analyses and orbital period variations for two contact binary stars,LS Del and V997 Cyg,are presented in this work which was conducted in the frame of the Binary Systems of South and North project Ground-based photometric observations were performed at two observatories in France.We used the Transiting Exoplanet Survey Satellite(TESS)data for extracting times of minima and light curve analysis of the targe systems.The O-C diagram for both systems displays a parabolic trend.LS Del and V997 Cyg’s orbital periods are increasing at rates of dP/dt=7.20×10^(-08)days yr^(-1)and dP/dt=2.54×10^(-08)days yr^(-1),respectively Therefore,it can be concluded that mass is being transferred from the less massive star to the more massive component with a rate of dM/dt=-1.96×10^(-7)M_(⊙)yr^(-1)for the LS Del system,and dM/dt=-3.83×10^(-7)M_(⊙)yr-1for V997 Cyg.The parameters of a third possible object in the system are also considered.The PHysics Of Eclipsing BinariEs Python code was used to analyze the light curves.The light curve solutions needed a cold starspot due to the asymmetry in the LS Del system’s light curve maxima.The mass ratio fill-out factor,and star temperature all indicate that both systems are contact binary types in this investigation.Two methods were applied to estimate the absolute parameters of the systems:one method relied on the parallax of Gaia DR3,and the other used a P-M relationship.The positions of the systems are also depicted on the M-L,M-R q-L_(ratio),and logM_(tot)-logJ_(0)diagrams.We recommend that further observations and investigations be done on the existence of a fourth body in this system. 展开更多
关键词 (stars:)binaries:eclipsing methods:observational stars:individual(LS Del and V997 Cyg)
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V0405 Dra:A New Deep and Low Mass Ratio Contact Binary with Extremely Fast Decrease in the Orbital Period
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作者 Chao-Yue Li Lin-Qiao Jiang +5 位作者 Jie Zheng Yi-Man Liu Xiao-Yu Long Min Sun Han-Lu Zhang Xiao-Man Tian 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第6期287-293,共7页
V0405 Dra is a W UMa-type binary star.Based on the TESS data,we have conducted an orbital period study and performed a light curve analysis for the system.The orbital period study reveals that the O-C curve for V0405 ... V0405 Dra is a W UMa-type binary star.Based on the TESS data,we have conducted an orbital period study and performed a light curve analysis for the system.The orbital period study reveals that the O-C curve for V0405 Dra exhibits secular decrease at an extremely high rate of d P/dt=-2.71×10^(-6)day year^(-1),along with periodic variations characterized by an amplitude of A_(3)=0.0032 day and a period of P_(3)=1.413 years.The orbital periodic change is possibly due to the light-travel time effect resulting from an additional third body in the system,for which we estimate a minimum mass of M_(3)=0.77M_(⊙).By employing the 2013 version of the Wilson-Devinney(W-D)method to synthesize a light curve,we derived photometric solutions indicating that V0405 Dra is a new deep(f=68.7%)and low-mass ratio(q=0.175)contact binary.The fast decrease in its orbital period is likely caused by mass transfer from the more massive primary star to the less massive secondary star,or due to angular momentum loss.With further mass transfer and loss of angular momentum,the binary will gradually evolve into a tighter contact configuration,eventually leading to a merger into a single star,following the evolutionary paths suggested for such deep and low mass ratio contact binaries. 展开更多
关键词 (stars:)binaries(including multiple):close (stars:)binaries:eclipsing stars:individual(V0405 Dra)
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Spectroscopic and photometric studies of a candidate pulsating star in an eclipsing binary:V948 Her
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作者 Filiz Kahraman Alicavus 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第7期133-144,共12页
Eclipsing binary stars with a pulsating component are powerful tools that allow us to probe the stellar interior structure and the evolutionary statuses with a good accuracy. Therefore, in this study, spectroscopic an... Eclipsing binary stars with a pulsating component are powerful tools that allow us to probe the stellar interior structure and the evolutionary statuses with a good accuracy. Therefore, in this study, spectroscopic and photometric examinations of an eclipsing binary system V948 Her are presented. The primary component of the system is classified to be a candidate 3 Scuti variable in the literature. The fundamental stellar, atmospheric and orbital parameters, and the surface abundance of the star were determined and the pulsation behaviour was investigated in this study. The orbital parameters were derived by the analysis of radial velocity and SuperWASP light curves. The spectral classification was found to be F2V. The initial atmospheric parameters of the primary component were derived by analysis of the spectral energy distribution and hydrogen lines. The final atmospheric parameters and chemical abundances of the primary component were obtained by using the method of spectrum synthesis. As a result, the final atmospheric parameters were determined as Teff= 7100±200 K, log 9= 4.34±0.1 cgs and ζ = 2.2 4± 0.2 km s^-1. The surface abundance was found to be similar to solar. The fundamental stellar parameters of both components were also obtained to be M = 1.722 4±0.123, 0.762 4± 0.020 Me, R = 1.655 4± 0.034,M,R= 0.689 ± 0.016 R for primary and secondary components, respectively. The pulsation characteristic of the primary component was examined using SuperWASP data and the pulsation period was found to be ~0.038 d. The position of the primary pulsating component was also obtained inside the instability strip of δ Sct stars. The primary component of V948 Her was defined to be a Sct variable. 展开更多
关键词 techniques PHOTOMETRIC spectroscopic-stars binaries eclipsing-stars variables δScuti-stars individual(v948 Her)
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The First Multiband Photometric Light Curve Solutions of the V Gru Binary System from the Southern Hemisphere
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作者 Mehmet Tanriver Atila Poro +2 位作者 Ahmet Bulut Ahmet Keskin Mark G.Blackford 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第5期44-51,共8页
The first multiband photometric solutions of the short-period V Gru eclipsing binary from the southern hemisphere are presented in this study.Light curves of the system were observed through BVI filters at the Congari... The first multiband photometric solutions of the short-period V Gru eclipsing binary from the southern hemisphere are presented in this study.Light curves of the system were observed through BVI filters at the Congarinni Observatory in Australia for 15 nights.In addition to the new ground-based data,we also used the TESS observations in two sectors.We analyzed the light curves of the system using the PHysics Of Eclipsing BinariEs(PHOEBE)2.4.7 version code to achieve the best accordance with the photometric observations.The solutions suggest that V Gru is a near-contact binary system with q=1.302(81)mass ratio,f_(1)=0.010(23),f_(2)=-0.0.009(21),and i=73.45(38).We considered the two hot spots on the hotter and cooler components for the light curve analysis.We extracted the minima times from the light curves based on the Markov Chain Monte Carlo(MCMC)approach.Using our new light curves,TESS,and additional literature minima,we computed the ephemeris of V Gru.The system’s eclipse timing variation trend was determined using the MCMC method.This system is a good and challenging case for future studies. 展开更多
关键词 (stars)binaries eclipsing-techniques photometric-stars individual(V Gru)
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An Improved Pair Method to Probe the Dust Extinction Law
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作者 Yuxi Wang Jian Gao +1 位作者 Yi Ren Jun Li 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第5期27-37,共11页
Dust extinction law is crucial to recover the intrinsic energy distribution of celestial objects and infer the characteristics of interstellar dust.Based on the traditional pair method,an improved pair method is propo... Dust extinction law is crucial to recover the intrinsic energy distribution of celestial objects and infer the characteristics of interstellar dust.Based on the traditional pair method,an improved pair method is proposed to model the dust extinguished spectral energy distribution(SED)of an individual star.Instead of the mathematically parameterizing extinction curves,the extinction curves in this work are directly from the silicate-graphite dust model,so that the dust extinction law can be obtained and the dust properties can be analyzed simultaneously.The ATLAS9 stellar model atmosphere is adopted for the intrinsic SEDs in this work,while the silicate-graphite dust model with a dust size distribution of dn da~a^(-a)exp(-a a_(c)),0.005<a<5μmfor each component is adopted for the model extinction curves.One typical extinction tracer in the dense region(V410 Anon9)and one in the diffuse region(Cyg OB2#12)of the Milky Way are chosen to test the reliability and the practicability of the improved pair method in different stellar environments.The results are consistent with their interstellar environments and are in agreement with the previous observations and studies,which prove that the improved pair method is effective and applicable in different stellar environments.In addition to the reliable extinction results,the derived parameters in the dust model can be used to analyze the dust properties,which cannot be achieved by other methods with the mathematical extinction models.With the improved pair method,the stellar parameters can also be inferred and the extinction law beyond the wavelengths of observed data can be predicted based on the dust model as well. 展开更多
关键词 STARS individual(V410 Anon 9 Cyg OB2#12)-interstellar medium(ISM)-ISM dust extinction
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单根一维TiO_2纳米线的电子输运性能 被引量:8
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作者 孙岚 左娟 +2 位作者 赖跃坤 聂茶庚 林昌健 《物理化学学报》 SCIE CAS CSCD 北大核心 2007年第10期1603-1606,共4页
采用电化学诱导溶胶-凝胶法,在多孔氧化铝模板(AAO)的纳米孔道内制备了直径分别为60和20nm的锐钛矿型TiO2纳米线阵列.利用原子力显微镜(AFM)技术,在半接触模式下得到了TiO2纳米线的形貌像,在接触模式下测量了单根TiO2纳米线的I-V曲线.T... 采用电化学诱导溶胶-凝胶法,在多孔氧化铝模板(AAO)的纳米孔道内制备了直径分别为60和20nm的锐钛矿型TiO2纳米线阵列.利用原子力显微镜(AFM)技术,在半接触模式下得到了TiO2纳米线的形貌像,在接触模式下测量了单根TiO2纳米线的I-V曲线.TiO2纳米线的电子输运性能表现为半导体的性质.TiO2纳米线的导通电压值明显小于TiO2块体,并且随着TiO2纳米线直径的减小,导通电压值增大. 展开更多
关键词 单根一维纳米线 TIO2 电子输运性能 I-V曲线
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三氧化二钒废水的处理研究 被引量:3
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作者 张丽杰 陈建中 +1 位作者 杨靖中 黄骏 《昆明理工大学学报(理工版)》 2002年第1期83-85,共3页
通过实验处理攀钢三氧化二钒废水 ,提出其处理流程为一步法和二步法 .经过处理出水均可达到《污水综合排放标准》(GB 8978- 1 996) .采用一步法对现有流程进行改造 ,改造后 ,每吨水的处理费用增加 3.5
关键词 三氧化二钒废水 一步法 二步法
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人权国际司法保护及其限度——基于对“蒂默诉荷兰”案的反思 被引量:1
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作者 邓华 《南京大学法律评论》 CSSCI 2016年第1期360-372,共13页
联合国人权事务委员会新近处理的“蒂默诉荷兰”案,不仅涉及到这样一个核心问题:具有准司法性质的人权条约机构,委员会出具的意见究竟能在多大程度上产生拘束力?而且触及一个更深层的命题:人权国际保护是否正在呈现出一种司法化的... 联合国人权事务委员会新近处理的“蒂默诉荷兰”案,不仅涉及到这样一个核心问题:具有准司法性质的人权条约机构,委员会出具的意见究竟能在多大程度上产生拘束力?而且触及一个更深层的命题:人权国际保护是否正在呈现出一种司法化的趋势,人权国际司法保护的空间究竟能有多大,限度又是在哪里?“二战”结束以来,全球层面国际人权条约监督实施机制和区域层面人权司法保护体系日益发展,人权国际保护机制在属性和运作上呈现出从纯粹政治属性到司法或准司法、类司法属性要素逐渐增多的某种迹象,人权国际保护蕴含着一定程度走向司法化的趋势及命题。但同时,源自于人权国际司法保护的艰巨性以及国家主权、大国政治、世界格局的复杂性,人权观念的差异性,国际司法机制本身的局限性,人权国际保护的多元性和补充性等因素,人权国际司法保护面对着极大的挑战与局限,构成了人权国际保护司法化的限度。随着全球化、国际法治和全球治理的兴起,人类命运一致性与人类文明共融性的凸显,以及人类精神、认知和学习能力的不断突破和国际合作机制的日益成熟,人权国际司法保护将可能走得更远,对此中国也将应当考虑如何参与其中和应对挑战。 展开更多
关键词 人权国际司法保护 限度 人权条约机构 个人来文“蒂默诉荷兰”案
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《术语工作 原则与方法》新版本读后感 被引量:1
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作者 全如瑊 《术语标准化与信息技术》 1999年第4期4-6,共3页
虽然西方国家对术语学的发展曾作出重大贡献,但他们的成就主要限于工业产品的术语。比较起来,中国在基础科学的术语方面已经积累了丰富的经验,而指称自然现象的基本术语要远比描述按既定规格制造的工业产品的名称难于处理。但长期以... 虽然西方国家对术语学的发展曾作出重大贡献,但他们的成就主要限于工业产品的术语。比较起来,中国在基础科学的术语方面已经积累了丰富的经验,而指称自然现象的基本术语要远比描述按既定规格制造的工业产品的名称难于处理。但长期以来中国的术语国家标准基本是按照ISO/TC 准备的稿件来制订的。在本文中,作者除了对ISO/ DIS 704 提出了一些意见之外,特别强调应将我国的经验融入我国将制订的新标准中,并应做到将一切示例本地化,以利我国广大术语工作者的理解和遵循,因为他们才是本文件的最终读者。 展开更多
关键词 个别概念 本质特征 转写法/标音法/意译法
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对“电视黄金时间”式微的思考 被引量:1
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作者 杨天瑜 《黄河科技大学学报》 2007年第3期60-61,共2页
电子时代,工作与娱乐间的界限日益缩小,个性化时间正支配着每个人的生活。人们可以个性化地选择在任何时间看电视,传统的电视黄金时间正失去昔日的影响力。因此,探讨电视黄金时间逐渐式微的背景、原因极有意义。
关键词 电视 黄金时间 个性化时间 式微
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基于V-VST评估的个性化喂养应用于神经源性吞咽功能障碍患者的效果分析 被引量:2
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作者 苏洁丹 陈国涛 《中外医学研究》 2022年第1期172-176,共5页
目的:分析基于容积-黏度吞咽试验(V-VST)评估的个性化喂养应用于神经源性吞咽功能障碍患者的效果。方法:选取2018年1月-2020年12月华中科技大学协和深圳医院收治的71例神经源性吞咽功能障碍患者,按照随机数字表法将患者分为对照组(n=35... 目的:分析基于容积-黏度吞咽试验(V-VST)评估的个性化喂养应用于神经源性吞咽功能障碍患者的效果。方法:选取2018年1月-2020年12月华中科技大学协和深圳医院收治的71例神经源性吞咽功能障碍患者,按照随机数字表法将患者分为对照组(n=35)和观察组(n=36)。对照组给予以洼田饮水试验为基础的饮食指导,观察组予以基于V-VST评估的个性化喂养。比较两组留置胃管情况、吞咽功能、营养状况及并发症发生情况。结果:观察组留置胃管人数少于对照组,留置时间短于对照组,差异均有统计学意义(P<0.05)。观察组吞咽功能优于对照组,差异有统计学意义(P<0.05)。干预前,两组三头肌皮褶厚度(TSF)、上臂围(MAC)、体质量指数(BMI)比较,差异均无统计学意义(P>0.05);干预后,两组TSF、AMC、BMI均优于治疗前,且观察组均优于对照组,差异均有统计学意义(P<0.05)。观察组并发症发生率为11.11%,低于对照组的31.43%,差异有统计学意义(P<0.05)。结论:基于V-VST评估的个性化喂养通过改善神经源性吞咽功能障碍患者的一般情况,调节吞咽功能,进而改善其营养状况且并发症发生率更低。 展开更多
关键词 基于V-VST评估的个性化喂养 神经源性吞咽功能障碍 营养状况 留置胃管
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The W UMa binaries USNO-A2.0 1350-17365531,V471 Cas,V479 Lac and V560 Lac:light curve solutions and global parameters based on Gaia distances 被引量:2
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作者 Diana P.Kjurkchieva Velimir A.Popov +1 位作者 Yordanka Eneva Nikola I.Petrov 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第1期141-148,共8页
We present photometric observations in Sloan filters g′, i′of the eclipsing W UMa stars USNOA2.0 1350-17365531, V471 Cas, V479 Lac and V560 Lac. The sinusoidal-like O-C diagram of V471 Cas indicates the presence of ... We present photometric observations in Sloan filters g′, i′of the eclipsing W UMa stars USNOA2.0 1350-17365531, V471 Cas, V479 Lac and V560 Lac. The sinusoidal-like O-C diagram of V471 Cas indicates the presence of a third body with mass 0.12 M_⊙(a red dwarf) at distance 897 R_⊙. The O-C diagram of V479 Lac reveals a period decrease of d P/dt =-1.69 × 10-6d yr-1. The results of the light curve solutions are:(i) the targets are overcontact binaries with small fill-out factors;(ii) their components are F–K stars, comparable in size, whose temperature differences are below 80 K;(iii) all targets undergo partial eclipses and to limit the possible mass ratios we carried out two-step q-search analysis. The target global parameters(luminosities, radii, masses) were obtained on the basis of their Gaia distances and the results of our light curve solutions. The obtained total mass of V560 Lac turns out to be smaller than the lower mass limit for presently known W UMa binaries of 1.0-1.2 M_⊙, i.e. this target is a peculiar overcontact system. 展开更多
关键词 binaries:close binaries:eclipsing methods:data analysis stars:fundamental PARAMETERS stars:individual(USNO-A2.0 1350-17365531 V471 Cas V479 Lac V560 Lac)
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New multi-color photometric investigations of solar-like contact binary V680 Per 被引量:1
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作者 Jing-Jing Wang Jia-Jia He Song-Qing Zhao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第4期49-56,共8页
High-precision CCD photometric observations of the contact binary V680 Per were obtained in2016.Its symmetric multi-color light curves were analyzed by using the Wilson–Devinney(2013)program.These photometric solutio... High-precision CCD photometric observations of the contact binary V680 Per were obtained in2016.Its symmetric multi-color light curves were analyzed by using the Wilson–Devinney(2013)program.These photometric solutions suggest that V680 Per is an A-type W UMa contact binary with the mass ratio of q=0.693 and a fill-out factor of f=18.84%with a small temperature difference of 101 K.Based on all minimum times,the O-C curve was analyzed for the first time in this study.A cyclic oscillation(A3=0.00093 d,T3=4.92 yr)superimposed on a secular decrease(d P/dt=-8.16×10-8 d yr-1)was identified.The continuous decrease in period is possibly a result of mass transfer from the more massive component to the less massive one,or angular momentum loss due to a magnetic stellar wind.Because of this secular decrease,it is predicted that the degree of contact will become higher,and V680 Per will evolve into a deeper overcontact binary. 展开更多
关键词 binaries:eclipsing stars:solar-type stars:individual(V680 Per)
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Photometric investigation and orbital period analyses of the W UMa binaries FP Lyn, FV CVn and V354 UMa 被引量:1
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作者 Raul Michel Qi-Qi Xia Jesus Higuera1 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第7期103-114,共12页
New light curves and photometric solutions of FP Lyn,FV CVn and V354 UMa are presented.We found that these three systems are W-subtype shallow contact binaries.In addition,it is obvious that the light curves of FP Lyn... New light curves and photometric solutions of FP Lyn,FV CVn and V354 UMa are presented.We found that these three systems are W-subtype shallow contact binaries.In addition,it is obvious that the light curves of FP Lyn and V354 UMa are asymmetric.Therefore,a hot spot was added on the primary star of FP Lyn and a dark spot was added on the secondary star of V354 UMa.At the same time,we added a third light to the photometric solution of FP Lyn for the final result.The obtained mass ratios and fill-out factors are q = 1.153 and f = 13.4% for FP Lyn,q = 1.075 and f = 4.6% for FV CVn,and q = 3.623 and f = 10.7% for V354 UMa respectively.The investigations of orbital period for these three systems indicate that the periods are variable.FP Lyn and V354 UMa were discovered to have secularly increasing components with rates of dp/dt = 4.19 ×10^-7 dyr^-1 and dp/dt = 7.70 ×10^-7 dyr^-1 respectively,which are feasibly caused by conservative mass transfer from the less massive component to the more massive component.In addition,some variable components were discovered for FV CVn,including a rate of dp/dt =-1.13 ×10^-6 dyr^-1 accompanied by a cyclic oscillation with amplitude and period of 0.0069 d and 10.65 yr respectively.The most likely explanation for the long-term decrease is angular momentum loss.The existence of an additional star is the most plausible explanation for the periodic variation. 展开更多
关键词 stars:binaries:close stars:binaries:eclipsing stars:individual (FP Lyn FV CVn and V354 UMa)
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一种适用于超高温超高压塑性泥岩的V形齿PDC钻头 被引量:10
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作者 罗鸣 朱海燕 +4 位作者 刘清友 王兆巍 李炎军 韩成 张超 《天然气工业》 EI CAS CSCD 北大核心 2021年第4期97-106,共10页
高密度钻井液静液柱压力和深部围压对近井区域形成的压持效应导致近井底区域泥岩呈现强硬塑性力学特征,钻头难以吃入、钻速较慢,同时还有可能因此诱发其他井下复杂情况,增加了钻完井成本。为了给深部塑性地层个性化PDC钻头的研制提供理... 高密度钻井液静液柱压力和深部围压对近井区域形成的压持效应导致近井底区域泥岩呈现强硬塑性力学特征,钻头难以吃入、钻速较慢,同时还有可能因此诱发其他井下复杂情况,增加了钻完井成本。为了给深部塑性地层个性化PDC钻头的研制提供理论与技术支撑,以南海西部莺琼盆地超高温高压巨厚泥岩为例,基于塑性泥岩的岩石力学实验,选择D-P岩石强度准则并确定了本构模型力学参数,并据此进行了PDC钻头齿组切削泥岩的数值模拟。研究结果表明:①通过对比V形齿齿组、脊形齿齿组和平面齿齿组破碎泥岩的力学机理,V形齿齿组较脊形齿齿组和平面齿齿组对该塑性泥岩攻击性更强、破碎效率更高;②在保证钻头抗磨性能的前提下,采用较小的后倾角和较大的齿组间距能够在高温高压塑性泥岩中取得更高的破岩效率;③研制出的V形齿个性化PDC钻头在现场应用中平均机械钻速为20.99 m/h,约为邻井常规PDC钻头的2.52倍,大幅度提升了该层段的机械钻速,出井钻头基体完整,内外锥部分均未出现明显严重破坏,仍可以继续使用。结论认为,该研究成果为莺琼盆地深部塑性泥岩层的高效钻井提供了理论与技术支撑。 展开更多
关键词 超高温超高压 塑性泥岩 破碎机理 V形齿 个性化PDC钻头 机械钻速 中国南海西部 莺琼盆地深部
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Multi-color light curves and orbital period research of eclipsing binary V1073 Cyg 被引量:1
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作者 Xiao-Man Tian Li-Ying Zhu +2 位作者 Sheng-Bang Qian Lin-Jia Li Lin-Qiao Jiang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第2期83-92,共10页
New multi-color BVRcIc photometric observations are presented for the W UMa type eclips- ing binary V1073 Cyg. The multi-color light curve analysis with the Wilson-Devinney procedure yielded the absolute parameters of... New multi-color BVRcIc photometric observations are presented for the W UMa type eclips- ing binary V1073 Cyg. The multi-color light curve analysis with the Wilson-Devinney procedure yielded the absolute parameters of this system, showing that V 1073 Cyg is a shallow contact binary system with a fill-out factor f = 0.124(±0.011). We collected all available times of light minima spanning 119yr, including CCD data to construct the O - C curve, and performed detailed O - C analysis. The O - C diagram shows that the period change is complex. A long-term continuous decrease and a cyclic vari- ation exist. The period is decreasing at a rate ofP = -1.04(±0.18) × 10-10 d cycle-land, with the period decrease, V1073 Cyg will evolve to the deep contact stage. The cyclic variation with a period of P3 = 82.7(±3.6) yr and an amplitude of A = 0.028(±0.002) d may be explained by magnetic activ- ity of one or both components or the light travel time effect caused by a distant third companion with M3(i1 = 90°) = 0.511 M⊙. 展开更多
关键词 stars: binaries: close -- stars: binaries: eclipse -- stars: binaries: individual (V1073 Cyg)
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Photometric investigations on two totally eclipsing contact binaries:V342 UMa and V509 Cam
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作者 Kai Li Qi-Qi Xia +6 位作者 Jin-Zhong Liu Yu Zhang Xing Gao Shao-Ming Hu Di-Fu Guo Xu Chen Yuan Liu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第10期75-86,共12页
By analyzing two sets of complete BV Rc Ic light curves for V342 UMa and three sets of complete BV Rc Ic light curves for V509 Cam, we determined that the two systems are both W-subtype contact binaries and that V342 ... By analyzing two sets of complete BV Rc Ic light curves for V342 UMa and three sets of complete BV Rc Ic light curves for V509 Cam, we determined that the two systems are both W-subtype contact binaries and that V342 UMa manifests a shallow contact configuration, while V509 Cam exhibits a medium contact configuration. Given that both of them are totally eclipsing binaries, the physical parameters derived only by the photometric light curves are reliable. Meanwhile, the period changes of the two targets were analyzed based on all available eclipsing times. We discovered that V342 UMa shows long-term period decrease with a rate of-1.02(±0.54)× 10^-7 d yr^-1 and that V509 Cam displays long-term period increase with a rate of 3.96(±0.90)× 10^-8 d yr^-1. Both the conservative mass transfer and angular momentum loss via magnetic stellar winds can be used to interpret the long-term period decrease of V342 UMa. The longterm period increase of V509 Cam can be explained by mass transfer from the less massive star to the more massive one. The absolute parameters of the two binaries were estimated according to their Gaia distances and our derived photometric solution results. This method can be extended to other contact binaries without radial velocities but with reliable photometric solutions. Their evolutionary states were investigated and we found that they reveal properties that are identical to other W-subtype contact systems. 展开更多
关键词 STARS BINARIES close-stars eclipsing-stars individual (V342UMa V509Cam)
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Photometric analysis and evolutionary stages of the contact binary V2790 Ori
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作者 Wichean Kriwattanawong Kriangsak Kriwattanawong 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第10期51-58,共8页
A photometric analysis and evolutionary stages of the contact binary V2790 Ori are presented.The BV RC observations were carried out at the Thai National Observatory. The photometric light curves were fitted to provid... A photometric analysis and evolutionary stages of the contact binary V2790 Ori are presented.The BV RC observations were carried out at the Thai National Observatory. The photometric light curves were fitted to provide fundamental parameters, required to examine evolutionary stages of the binary. The results indicate that V2790 Ori is a W-type contact system with a mass ratio of q = 2.932. The orbital period increase is found at a rate of d P/dt = 1.03×10^-7 d yr^-1. This implies that a rate of mass transfer from the secondary component to the primary one is dm2/dt =6.31×10^-8 M⊙yr^-1. Furthermore, we find that from the detached phase to the contact phase, the amount of mass that the evolved secondary component has lost is 1.188±0.110 M⊙, i.e., mass lost by the system is 0.789±0.073 M⊙and mass transfer to the primary is0.399±0.037 M⊙. Since the time of the first overflow, the angular momentum loss is found to be 72.2% of JFOF, causing the orbit and Roche surface to shrink until the present time. 展开更多
关键词 STARS BINARIES close-stars eclipsing-stars individual V2790 Ori
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A low-mass-ratio and deep contact binary as the progenitor of the merger V1309 Sco 被引量:1
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作者 Li-Ying Zhu Er-Gang Zhao Xiao Zhou 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2016年第4期129-132,共4页
Nova Sco 2008 (=V1309 Sco) is an example of a V838 Mon type eruption rather than a typical classical nova. This enigmatic object was recently shown to have resulted from the merger of two stars in a contact binary. ... Nova Sco 2008 (=V1309 Sco) is an example of a V838 Mon type eruption rather than a typical classical nova. This enigmatic object was recently shown to have resulted from the merger of two stars in a contact binary. It is the first stellar merger that was identified to be undergoing a common envelope transient. To understand the properties of its binary progenitor, the pre-outburst light curves were analyzed by using the W-D method. The photometric solution of the 2002 light curve shows that it is a deep contact binary (f = 89.5(~40.5)%) with a mass ratio of 0.094. The asymmetry of the light curve is explained by the presence of a dark spot on the more massive component. The extremely high fill-out factor suggests that the merging of the contact binary is driven by dynamical mass loss from the outer Lagrange point. However, the analysis of the 2004 light curve indicates that no solutions were obtained even at an extremely low mass ratio of q = 0.03. This suggests that the common convective envelope of the binary system disappeared and the secondary component spiraled into the envelope of the primary in 2004. Finally, the ejection of the envelope of the primary produced the outburst. 展开更多
关键词 stars: binaries: close -- stars: binaries: eclipsing -- stars: individuals (V1309 Sco) -- stars:evolution -- stars: mass-loss
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