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障碍物阻塞率对氢-空气爆燃的影响
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作者 汪瑞齐 张彬 +2 位作者 夏远辰 王博乔 宋瑞林 《船舶工程》 CSCD 北大核心 2024年第S01期333-339,共7页
为深入了解氢气在不同阻塞率条件下的爆燃特性,以提升氢能使用的安全性,并为氢能在船舶和生活领域安全应用以及抗爆减灾设计提供科学依据。研究利用Open FOAM软件结合大涡模拟(LES)模型,对半开敞管道内氢气在不同阻塞率条件下的爆燃火... 为深入了解氢气在不同阻塞率条件下的爆燃特性,以提升氢能使用的安全性,并为氢能在船舶和生活领域安全应用以及抗爆减灾设计提供科学依据。研究利用Open FOAM软件结合大涡模拟(LES)模型,对半开敞管道内氢气在不同阻塞率条件下的爆燃火焰动力学特性进行了深入分析。研究发现障碍物的阻塞率显著影响氢气爆燃的火焰传播速度和爆燃压力;火焰结构的演化过程可划分为球形、指形、射流和漩涡4个阶段;在面积阻塞率为0.7时,火焰传播速度达到极大值177.5 m/s,相较于阻塞率为0.5和0.3时分别快1.31倍和1.82倍;相同阻塞率下,不同厚度的障碍物对火焰速度的影响不大;爆燃压力在阻塞率为0.7时达到峰值74.7 kPa,较阻塞率为0.5和0.3时分别高出1.32倍和1.7倍,同时火焰结构和行为受到未燃气体流场的显著影响,为氢能设备的安全设计和布置提供重要的理论基础,并对氢气爆炸的抗爆减灾设计具有重要的理论支撑作用。通过这项研究,可更有效地预防和减轻氢气爆燃带来的风险,确保氢能在船舶和生活领域的安全应用。 展开更多
关键词 -空气爆燃 火焰 体积阻塞率 大涡模拟 open FOAM
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Variable Stars in the 50BiN Open Cluster Survey.Ⅲ.NGC 884
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作者 Lin-Hong Wang Qian-Heng Nie +5 位作者 Kun Wang Xiao-Dian Chen Chun-Guang Zhang Li-Cai Deng Xiao-Bin Zhang Tian-Lu Chen 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第2期36-45,共10页
Open clusters are the basic building blocks that serve as a laboratory for the study of young stellar populations in the Milky Way.Variable stars in open clusters provide a unique way to accurately probe the internal ... Open clusters are the basic building blocks that serve as a laboratory for the study of young stellar populations in the Milky Way.Variable stars in open clusters provide a unique way to accurately probe the internal structure,temporal and dynamical evolutionary stages of individual stars and the host cluster.The most powerful tool for such studies is time-domain photometric observations.This paper follows the route of our previous work,concentrating on a photometric search for variable stars in NGC 884.The target cluster is the companion of NGC869,forming the well-known double cluster system that is gravitationally bound.From the observation run in 2016 November,a total of 9247 B-band CCD images and 8218Ⅴ-band CCD images were obtained.We detected a total of 15 stars with variability in visual brightness,including five Be stars,three eclipsing binaries,and seven of unknown types.Two new variable stars were discovered in this work.We also compared the variable star content of NGC 884 with its companion NGC 869. 展开更多
关键词 STARS variables general-(Galaxy:)open clusters and associations individual(… …)-(stars:)binaries GENERAL
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Address by the UN High Commissioner for Human Rights Ms. Louise Arbour at the Opening Ceremony of the 13th Annual Workshop of the Framework on Regional Cooperation for the Promotion and Protection of Human Rights in the Asia-Pacific Region 被引量:1
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作者 Louise Arbour 《The Journal of Human Rights》 2005年第6期4-6,共3页
关键词 Louise Arbour at the opening Ceremony of the 13th Annual Workshop of the Framework on Regional Cooperation for the Promotion and Protection of Human Rights in the Asia-Pacific Region address by the UN High Commissioner for Human Rights Ms Asia UN
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Process for improving the ladle free- opening rate for high aluminum steel in continuous casting 被引量:3
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作者 LIU Junzhan ZHOU Tongjun LUO Hui 《Baosteel Technical Research》 CAS 2015年第1期42-45,共4页
Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. Accor... Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are:sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel. 展开更多
关键词 continuous casting high aluminum steel LADLE free - opening rate
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Opening Address to the 1987 International Conference of the System Dynamics Society
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《上海理工大学学报》 CAS 1987年第4期91-94,共4页
1987年国际系统动力学会议于今年6月9日至12日在上海召开。同时,会议收到的各国学者的64篇论文也在我院汇篇成论文集。现选择其中有代表性的6篇在本刊发表,本期刊登的是:国务院发展研究中心总干事、我国著名社会经济学家马洪教授的开幕... 1987年国际系统动力学会议于今年6月9日至12日在上海召开。同时,会议收到的各国学者的64篇论文也在我院汇篇成论文集。现选择其中有代表性的6篇在本刊发表,本期刊登的是:国务院发展研究中心总干事、我国著名社会经济学家马洪教授的开幕词;国际系统动力学创始人、美国MIT教授Jay.W.Forrester的“系统动力学在城市与区域发展分析上的应用”;国际系统动力学协会政策委员会委员、全国系统动力学学术委员会筹委会主任、本院王其藩教授的“系统动力学的哲学观和基本理论”。 展开更多
关键词 王其藩 opening address to the 1987 International Conference of the System Dynamics Society 系统动力学 系统动态学
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New open cluster candidates discovered in the XSTPS-GAC survey
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作者 Jin-Cheng Guo Hua-Wei Zhang +12 位作者 Hui-Hua Zhang Xiao-Wei Liu Hai-Bo Yuan Yang Huang Song Wang Li Chen Hai-Bin Zhao Ji-Feng Liu Bing-Qiu Chen Mao-Sheng Xiang Zhi-Jia Tian Zhi-Ying Huo Chun Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第3期77-90,共14页
The Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-center(XSTPS-GAC)is a photometric sky survey that covers nearly 6000 deg^2 towards the Galactic Anti-center(GAC) in the g,r,i bands. Half of its s... The Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-center(XSTPS-GAC)is a photometric sky survey that covers nearly 6000 deg^2 towards the Galactic Anti-center(GAC) in the g,r,i bands. Half of its survey field is located on the Galactic Anti-center disk,which makes XSTPSGAC highly suitable to search for new open clusters in the GAC region. In this paper,we report new open cluster candidates discovered in this survey,as well as properties of these open cluster candidates,such as age,distance and reddening,derived by isochrone fitting in the color-magnitude diagram(CMD).These open cluster candidates are stellar density peaks detected in the star density maps by applying the method from Koposov et al. Each candidate is inspected in terms of its true color image composed from three XSTPS-GAC band images. Then its CMD is checked,in order to identify whether the central region stars have a clear isochrone-like trend differing from background stars. The parameters derived from isochrone fitting for these candidates are mainly based on three band photometry of XSTPS-GAC.Moreover,when these new candidates are able to be seen clearly in 2 MASS data,their parameters are also derived based on the 2 MASS(J-H,J) CMD. There are a total of 320 known open clusters rediscovered and 24 new open cluster candidates discovered in this work. Furthermore,the parameters of these new candidates,as well as another 11 previously known open clusters,are properly determined for the first time. 展开更多
关键词 open clusters and associations general - Galaxy structure - methods data analysis
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A Study on Modifying the Calculation Model of Valid Opening Size of Heat-bonded Nonwoven Fabrics
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作者 余序芬 吴美萍 《Journal of China Textile University(English Edition)》 EI CAS 1999年第3期52-56,共5页
It has been found that there are marked errors in the value of valid opening size of heat-bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is adva... It has been found that there are marked errors in the value of valid opening size of heat-bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is advanced in this paper. The equivalent diameter of the pore of a fibre web is used to calculate the valid opening size instead of the maximum diameter of inscribed circle used, because the fibres in practical fibre webs are flexible elastomers with definite diameters and the pore of fibre web may produce deformation in screening teat and engineering usage. The results show that the theoretical calculations coincide well with the engineering measurements. This method offers a theoretical basis for computer simulation to the performance of filters of heatbonded nonwoven fabrics. 展开更多
关键词 HEAT - bonded NONWOVEN fabrics theoretical MODEL VALID openING SIZE MODEL modification .
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Address by Mr. Zhou Tienong at the Opening Ceremony of the 2013 “Understanding and Cooperation” Dialogue
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作者 Ma Jingjing 《International Understanding》 2013年第3期19-21,共3页
Distinguished Guests,Ladies and Gentlemen,Dear friends,On behalf of the Chinese Association for International Understanding(CAFIU),I would like to start by extending my warmest welcome to all representatives from home... Distinguished Guests,Ladies and Gentlemen,Dear friends,On behalf of the Chinese Association for International Understanding(CAFIU),I would like to start by extending my warmest welcome to all representatives from home and abroad,who come to attend the 2013"Understanding 展开更多
关键词 Understanding and Cooperation address by Mr DIALOGUE Zhou Tienong at the opening Ceremony of the 2013
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An application of the KNND method for detecting nearby open clusters based on Gaia-DR1
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作者 Xin-Hua Gao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2017年第6期89-94,共6页
This paper presents a preliminary test of the k-th nearest neighbor distance (KNND) method for detecting nearby open clusters based on Gaia-DR1. We select 38 386 nearby stars (〈 100 pc) from the Gaia-DR1 catalog,... This paper presents a preliminary test of the k-th nearest neighbor distance (KNND) method for detecting nearby open clusters based on Gaia-DR1. We select 38 386 nearby stars (〈 100 pc) from the Gaia-DR1 catalog, and then use the KNND method to detect overdense regions in three-dimensional space. We find two overdense regions (the Hyades and Coma Berenices (Coma Ber) open clusters), and obtain 57 reliable cluster members. Based on these cluster members, the distances to the Hyades and Coma Ber clusters are determined to be 46.0±0.2 and 83.5±0.3 pc, respectively. Our results demonstrate that the KNND method can be used to detect open clusters based on a large volume of astrometry data. 展开更多
关键词 open clusters and associations individual (Hyades Coma Ber) - astrometry- parallaxes- stars distances
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ADDRESS TO THE OPENING CEREMONY OF THE 8th YOUNG ASTRONAUTS INTERNATIONAL CONFERENCE
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作者 Mr. Liu Jiyuan, Administrator of China National Space Administration and President of the Chinese Society of Astronautics 《Aerospace China》 1995年第2期4-4,共1页
I’d like to take this opportunity,, on behalf of China National Space Administration and the host organization, the Chinese Society of Astronautics, to extend our best wishes to the opening of the Conference and warm... I’d like to take this opportunity,, on behalf of China National Space Administration and the host organization, the Chinese Society of Astronautics, to extend our best wishes to the opening of the Conference and warmly welcome all delegates here both from home and abroad. The Young Astronauts International is an international organization which devotes itself to the space popular science education among young people. 展开更多
关键词 address TO THE openING CEREMONY OF THE 8th YOUNG ASTRONAUTS INTERNATIONAL CONFERENCE
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Boost the Modernization of Human Rights Protection Systems and Endeavor to Fulfill the Chinese Dream——An Address at the Opening Ceremony of the 7th Beijing Forum on Human Rights, Sept. 17, 2014
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作者 LUO HAOCAI 《The Journal of Human Rights》 2014年第6期4-7,共4页
This session of the Forum has the theme, “The Chinese Dream: New Progress in the Cause of Human Rights in China.” This theme concentrates on such important subtopics as “The Chinese Dream and Human Rights” ,
关键词 An address at the opening Ceremony of the 7th Beijing Forum on Human Rights Boost the Modernization of Human Rights Protection Systems and Endeavor to Fulfill the Chinese Dream Sept
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Keep Firmly to the Road of Human Rights Development Suitable to China's National Situation——An Address at the Opening Ceremony of the 7th Beijing Forum on Human Rights, Sept. 17, 2014
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作者 CAI MINGZHAO 《The Journal of Human Rights》 2014年第6期11-14,共4页
In November 2012, immediately after the close of the 18th National Congress of the Communist Party of China (CPC), CPC Central Committee General Secretary Xi Jinping proposed to "realize the Chinese dream of the gr... In November 2012, immediately after the close of the 18th National Congress of the Communist Party of China (CPC), CPC Central Committee General Secretary Xi Jinping proposed to "realize the Chinese dream of the great revival of the Chinese nation." He emphasized that the fulfillment of the Chinese dream regarding the great revival of the Chinese nation is simply the realization of the country's prosperity, the nation's revival and the people's happiness. All in all, the Chinese dream is the people's dream. 展开更多
关键词 Keep Firmly to the Road of Human Rights Development Suitable to China’s National Situation Sept An address at the opening Ceremony of the 7th Beijing Forum on Human Rights
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Create an International Environment for the Peaceful and Steady Development to Boost the Sound Development of Human Rights on the International Stage——An Address at the Opening Ceremony of the 7th Beijing Forum on Human Rights, Spet. 17, 2014
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作者 HUANG MENGFU 《The Journal of Human Rights》 2014年第6期8-10,共3页
Since its initiation in 2008, the Beijing Forum on Human Rights has been bent on promoting our mutual understanding and expanding our common grounds. It has carried out very fruitful exchanges and researches around ma... Since its initiation in 2008, the Beijing Forum on Human Rights has been bent on promoting our mutual understanding and expanding our common grounds. It has carried out very fruitful exchanges and researches around many important questions concerning human rights development, and hence attained great achievements. It has played avery constructive role in promoting exchanges about and cooperation in human rights between China and other countries, becoming an important and influential platform for international dialogs over human rights. 展开更多
关键词 In Create an International Environment for the Peaceful and Steady Development to Boost the Sound Development of Human Rights on the International Stage SPET An address at the opening Ceremony of the 7th Beijing Forum on Human Rights
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Pathogenesis and clinical features of severe hepatitis E virus infection
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作者 László Orosz Károly Péter Sárvári +2 位作者 Áron Dernovics András Rosztóczy Klára Megyeri 《World Journal of Virology》 2024年第2期19-33,共15页
The hepatitis E virus(HEV),a member of the Hepeviridae family,is a small,non-enveloped icosahedral virus divided into eight distinct genotypes(HEV-1 to HEV-8).Only genotypes 1 to 4 are known to cause diseases in human... The hepatitis E virus(HEV),a member of the Hepeviridae family,is a small,non-enveloped icosahedral virus divided into eight distinct genotypes(HEV-1 to HEV-8).Only genotypes 1 to 4 are known to cause diseases in humans.Genotypes 1 and 2 commonly spread via fecal-oral transmission,often through the consum-ption of contaminated water.Genotypes 3 and 4 are known to infect pigs,deer,and wild boars,often transferring to humans through inadequately cooked meat.Acute hepatitis caused by HEV in healthy individuals is mostly asymptomatic or associated with minor symptoms,such as jaundice.However,in immunosup-pressed individuals,the disease can progress to chronic hepatitis and even escalate to cirrhosis.For pregnant women,an HEV infection can cause fulminant liver failure,with a potential mortality rate of 25%.Mortality rates also rise amongst cirrhotic patients when they contract an acute HEV infection,which can even trigger acute-on-chronic liver failure if layered onto pre-existing chronic liver disease.As the prevalence of HEV infection continues to rise worldwide,highlighting the particular risks associated with severe HEV infection is of major medical interest.This text offers a brief summary of the characteristics of hepatitis developed by patient groups at an elevated risk of severe HEV infection. 展开更多
关键词 Hepatitis E virus CIRRHOSIS Acute-on-chronic liver failure PREGNANCY Immune dysfunction open reading frames 1-4
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Abundance Gradient from Open Clusters and Implications for the Galactic Disk Evolution 被引量:3
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作者 Jin-LiangHou Rui-XiangChang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2002年第1期17-32,共16页
We compile a new sample of 89 open clusters with ages, distances and metallicities available. We derive a radial iron gradient of about -0.099±0.008 dex kpc^(-1) (unweighted) for the whole sample, which is somewh... We compile a new sample of 89 open clusters with ages, distances and metallicities available. We derive a radial iron gradient of about -0.099±0.008 dex kpc^(-1) (unweighted) for the whole sample, which is somewhat greater than the most recent determination of oxygen gradient from nebulae and young stars. By dividing the clusters into age groups, we show that the iron gradient was steeper in the past and has evolved slowly in time. Current data show a substantial scatter of the cluster metallicities indicating that the Galactic disk has undergone a very rapid, inhomogeneous enrichment. Also, based on a simple, but quite successful model of chemical evolution of the Milky Way disk, we make a detailed calculation of the iron abundance gradient and its time evolution. The predicted current iron gradient is about -0.072 dex kpc^(-1). The model also predicts a steady flattening of the iron gradient with time, which agrees with the result from our open cluster sample. 展开更多
关键词 open clusters: abundances - Galaxy: formation - Galaxy: evolution
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超越范式:OPEN建筑事务所的校园建筑实践 被引量:3
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作者 莫万莉 《世界建筑》 2022年第3期24-27,共4页
文章以传统校园建筑的组织模式为切入点,对OPEN建筑事务所近年来完成的北京四中房山校区和上海青浦平和双语学校展开分析。文章认为,校园建筑作为孩童长期生活的空间,往往潜移默化地通过空间的媒介性作用折射出不同时期的教育理念。两... 文章以传统校园建筑的组织模式为切入点,对OPEN建筑事务所近年来完成的北京四中房山校区和上海青浦平和双语学校展开分析。文章认为,校园建筑作为孩童长期生活的空间,往往潜移默化地通过空间的媒介性作用折射出不同时期的教育理念。两座校园中虽然面临快速城市化所导致的相似挑战,但在规划组织与单体布局层面上显露出截然不同的策略,并共同试图超越校园建筑的传统范式。 展开更多
关键词 校园建筑 城市性 走廊-教室 open建筑事务所
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WORLD NEWS IN BRIEF(August 1-15, 1989)
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《国际展望》 北大核心 1989年第16期32-32,共1页
The international conference on Kampuchea declded on August 1 in Paris to send a UN fact-finding mission to the country to arrange a peace settlement. The Fatah Movement, the mainstream group in the Palestine Liberati... The international conference on Kampuchea declded on August 1 in Paris to send a UN fact-finding mission to the country to arrange a peace settlement. The Fatah Movement, the mainstream group in the Palestine Liberation Organization (PLO), opened its fifth general congress on August 3 in Tunis. PLO Chairman and President of the State of Palestine Yasser Arafat and Tunisian President Zine E1 Abidine Ben All addressed the opening ceremony. 展开更多
关键词 MAINSTREAM CEREMONY ARRANGE addressed CONGRESS Chairman finding AUGUST 1-15 peace FIFTH
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Weak Elliptical Distortion of the Milky Way Potential traced by Open Clusters
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作者 Zi Zhu 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2008年第1期96-102,共7页
From photometric observations and star counts, the existence of a bar in the central few kpc of the Galaxy is suggested. It is generally thought that our Galaxy is surrounded by a massive invisible halo. The gravitati... From photometric observations and star counts, the existence of a bar in the central few kpc of the Galaxy is suggested. It is generally thought that our Galaxy is surrounded by a massive invisible halo. The gravitational potential of the Galaxy is therefore made nonaxisymmetric generated by the central triaxial bar, by the outer triaxial halo, and/or by the spiral structures. Selecting nearly 300 open clusters with complete spatial velocity measurements and ages, we were able to construct the rotation curve of the Milky Way within a range of 3 kpc of the Sun. Using a dynamic model for an assumed elliptical disk, a clear weak elliptical potential of the disk with ellipticity of ε(R0) = 0.060 4± 0.012 is detected, the Sun is found to be near the minor axis, displaced by 30°±3°. The motion of the clusters is suggested to be on an oval orbit rather than on a circular one. 展开更多
关键词 GALAXY disk - Galaxy kinematics and dynamics - Galaxy open clusters and associations general - Galaxy structure
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WORLD NEWS IN BRIEF (March 16-31, 1989)
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《国际展望》 北大核心 1989年第7期32-32,共1页
The U.S. Senate unanimously confirmed, by a.92 to 0 vote, Representative Dick Cheney as defence secretary on March 17. On March 18, the US space shuttle "Discovery" landed in California, completing a flight ... The U.S. Senate unanimously confirmed, by a.92 to 0 vote, Representative Dick Cheney as defence secretary on March 17. On March 18, the US space shuttle "Discovery" landed in California, completing a flight of nearly five days that covered about three million kilometres. The Second Session of the Seventh National People’s Congress opened on March 20 in Beijing. Chinese Premier Li 展开更多
关键词 Premier NEWS MARCH 16-31 SHUTTLE California opened COVERED PEACE AMBASSADOR party
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Investigation of Galactic open cluster remnants: the case of NGC 7193
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作者 Mateus de Souza Angelo Joao Francisco Coelho dos Santos Jr +2 位作者 Wagner Jose Barbosa Corradi Francisco Ferreira de Souza Maia Andres Eduardo Piatti 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2017年第1期31-54,共24页
Galactic open clusters (OCs) that survive the early gas-expulsion phase are gradually de- stroyed over time by the action of disruptive dynamical processes. Their final evolutionary stages are characterized by a poo... Galactic open clusters (OCs) that survive the early gas-expulsion phase are gradually de- stroyed over time by the action of disruptive dynamical processes. Their final evolutionary stages are characterized by a poorly populated concentration of stars called an open cluster remnant (OCR). This study is devoted to assessing the real physical nature of the OCR candidate NGC 7193. GMOS/Gemini spectroscopy of 53 stars in the inner target region were obtained to derive radial velocities and at- mospheric parameters. We also employed photometric and proper motion data. The analysis method consists of the following steps: (i) analysis of the statistical resemblance between the cluster and a set of field samples with respect to the sequences defined in color-magnitude diagrams (CMDs); (ii) a 5-dimensional iterative exclusion routine was employed to identify outliers from kinematical and posi- tional data; (iii) isochrone fitting to thes× (J - Ks) CMD of the remaining stars and the dispersion of spectral types along empirical sequences in the (J - H) × (H - Ks) diagram were checked. A group of stars was identified for which the mean heliocentric distance is compatible with that obtained via isochrone fitting and whose metallicities are compatible with each other. Fifteen of the member stars observed spectroscopically were identified together with another 19 probable members. Our results indi- cate that NGC 7193 is a genuine OCR, of a once very populous OC, for which the following parameters were derived: d = 501±46 pc, t = 2.5±1.2 Gyr, ([Fe/H]) = -0.17±0.23 and E(B-V) = 0.05±0.05. Its luminosity and mass functions show depletion of low mass stars, confirming the OCR is in a dynam- ically evolved state. 展开更多
关键词 open cluster remnants - Galactic open clusters
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