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玩具材料中某些元素转移测试条件的选择 被引量:1
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作者 江丽媛 李宣 +1 位作者 刘斌斌 贺一训 《现代商检科技》 1998年第5期19-21,共3页
一、前言欧洲共同体是全球最大的玩具销售市场之一,也是中国制造的玩具的最大输入地之一。只有符合欧共体玩具安全标准EN71的玩具产品,才允许在欧共体市场内销售,因此EN71是我们日常检验工作中最常使用的检验标准。EN71... 一、前言欧洲共同体是全球最大的玩具销售市场之一,也是中国制造的玩具的最大输入地之一。只有符合欧共体玩具安全标准EN71的玩具产品,才允许在欧共体市场内销售,因此EN71是我们日常检验工作中最常使用的检验标准。EN71第三部分规定了玩具材料中八种元素转... 展开更多
关键词 玩具材料 元素转移 测试
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南沙珊瑚礁生态系中元素的垂直转移途径 被引量:7
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作者 宋金明 《海洋与湖沼》 CAS CSCD 北大核心 1999年第1期1-5,共5页
于1993年和1994年用沉积物捕捉器采集南沙永暑礁和诸碧礁内的沉降颗粒物,用中干活化法分析兀素的含量并计算通量,通过对生源要素的统计相关分析、垂直沉降颗粒物中的元素比、非生源要素在泻湖中的停留时间的探讨,研究了南沙珊瑚礁生... 于1993年和1994年用沉积物捕捉器采集南沙永暑礁和诸碧礁内的沉降颗粒物,用中干活化法分析兀素的含量并计算通量,通过对生源要素的统计相关分析、垂直沉降颗粒物中的元素比、非生源要素在泻湖中的停留时间的探讨,研究了南沙珊瑚礁生态系中元素的垂直转移途径。结果表明,在南沙珊瑚礁泻湖中元素的停留时间较海水中短,元素的循环速率高,且尤以与生物作用有关的元素为甚;颗粒物中非生源要素的垂直转移主要是通过生物过程完成的,其转移量可达80%以上,表明珊瑚礁生态系中非生源元素与生源元素有相似的垂直转移机制。 展开更多
关键词 非生源元素 南沙 珊瑚礁 生态系 元素转移
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中国土壤中元素经膳食向人体转移的研究 被引量:1
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作者 诸洪达 樊体强 +2 位作者 武权 刘庆芬 张维 《中国辐射卫生》 北大核心 2007年第4期385-388,共4页
目的计算元素从我国土壤经膳食向成年男子全身的转移系数和碱土元素、碱金属元素DF值。方法依据本系列研究所获我国成年男子膳食元素摄入量更新值和68例尸体全身负荷量,并引用我国土壤背景值,按照UNSCEAR环境转移模式和观察比法分别计... 目的计算元素从我国土壤经膳食向成年男子全身的转移系数和碱土元素、碱金属元素DF值。方法依据本系列研究所获我国成年男子膳食元素摄入量更新值和68例尸体全身负荷量,并引用我国土壤背景值,按照UNSCEAR环境转移模式和观察比法分别计算了元素在土壤、膳食和全身三环节间转移系数和DF值。结果获得了50种元素由土壤经膳食向全身的转移系数,碱土元素(包括Pb)和碱金属元素在这三环节间DF值。结论这些元素的P23或P234都比P34小得多;P23、P34和P234分别以Hg、Ca和Se最高,而以Ce、In和Y最低;稀土元素的P23和P234都小于碱金属或碱土元素。碱土元素从土壤-膳食-全身的DF都小于1,自钙随原子序的增大或减小,DF值都呈递减趋势,铅DF值在锶和钡之间。碱金属元素铷或铯从土壤向膳食转移DF小于1,而由膳食向全身转移DF大于1。 展开更多
关键词 元素转移 土壤 膳食摄入量 全身负荷量
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瑞典富营养和贫营养湖泊中金属元素的转移
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作者 Gran Lithner Hans Borg +7 位作者 Jrgen Ek Elisabeth Frberg Karin Holm Ann-Marie Johansson Pia Krrhage GranRosén Maria Sderstrm 李康民 《AMBIO-人类环境杂志》 2000年第4期216-228,291,共13页
我们对湖泊中的微量金属元素进行了动力学研究,以期说明湖泊富营养化对金属元素的转移有无直接和间接影响。在确定了年代的沉积物柱状样品中,铅的纵向分布图很好地反映了大气中铅负荷正逐渐下降的情况。不过,这种趋势受重悬浮作用的影响... 我们对湖泊中的微量金属元素进行了动力学研究,以期说明湖泊富营养化对金属元素的转移有无直接和间接影响。在确定了年代的沉积物柱状样品中,铅的纵向分布图很好地反映了大气中铅负荷正逐渐下降的情况。不过,这种趋势受重悬浮作用的影响,有时这种作用控制了颗粒成为沉积物的通量。由于硫化物对沉积物中金属元素束缚过程起重要作用,重悬浮作用和水循环有利于污染物的扩散而金属硫化物则由于硫化物的氧化而使溶解更为便利。在富营养化湖泊沉积物中铅和汞水平的下降表明"悬浮稀释"的作用十分明显。不过,不同于镉和铊,鱼对那些金属元素的生物可得性并未下降。在富营养化湖泊,鱼肌肉中汞的高浓度随着冷水层中甲基汞净生成量的不断增加也不断提高。在富营养化湖泊中金属元素的高通量,部分可以用较高的生物量来解释,部分可以用不同的地质学和pH来解释。湖泊的富营养化减少了铜、镍、铊的存留时间,也许部分是由于硫化物的固定作用。水中镉、钼浓度的下降是由于巨大的生物量和金属元素的有效清除所造成的。 展开更多
关键词 富营养 贫营养 湖泊 金属元素转移 瑞典
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树木叶片衰老过程中养分元素内吸收研究 被引量:21
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作者 王文卿 林鹏 《武汉植物学研究》 CSCD 1999年第A09期117-122,共6页
关键词 叶片衰老 元素转移 养分吸收 植物 内吸收
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虎纹捕鸟蛛体内矿质元素变化与越冬关系的研究 被引量:1
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作者 郑文升 王智 《常德师范学院学报(自然科学版)》 2001年第2期93-94,共2页
安全越冬的蜘蛛 ,体内Ca2 + 、Mg2 + 含量以腹部和头胸部为多 (38%~ 44 % ) ;附肢最少 ,分别占 11%和 3%。越冬死亡的蜘蛛体内上述二种元素的分布状况发生异常 ,集中表现在头胸部和腹部含量减少 ,附肢内大量增加。首次发现了矿质元素... 安全越冬的蜘蛛 ,体内Ca2 + 、Mg2 + 含量以腹部和头胸部为多 (38%~ 44 % ) ;附肢最少 ,分别占 11%和 3%。越冬死亡的蜘蛛体内上述二种元素的分布状况发生异常 ,集中表现在头胸部和腹部含量减少 ,附肢内大量增加。首次发现了矿质元素在该蛛体内具有转移现象 。 展开更多
关键词 虎纹捕鸟蛛 越冬机理 矿质元素 元素转移 含量分布
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Nutrient characteristics in rhizosphere of pure and mixed plantations of Manchur ian walnut and Dahurian larch 被引量:8
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作者 陈永亮 韩士杰 史向民 《Journal of Forestry Research》 SCIE CAS CSCD 2001年第1期18-20,共4页
A comparison study was made for the characteristics of pH value, orga nic matter content, nutrient element N, P and K contents in rhizosphere soils of pure and mixed plantations of Manchurian walnut and Dahurian larc... A comparison study was made for the characteristics of pH value, orga nic matter content, nutrient element N, P and K contents in rhizosphere soils of pure and mixed plantations of Manchurian walnut and Dahurian larch and in bulk soils. The results show that the pH values of rhizosphere soil for all the plant ations except the pure walnut stand, which was slightly higher, were lower than those of bulk soils, while the organic matter contents in the rhizosphere soil f or all the plantations except the mixed plantation, which was slightly lower, we re higher than that in bulk soil. There exists a relative nitrogen accumulation in the rhizosphere and the extent to which the nitrogen accumulates is closely r elated to tree species and mixed pattern. As far as the total P and K contents a re considered, there exists a deficient tendency in rhizosphere in comparison wi th bulk soil. The element N, P and K are all mobilized in the rhizosphere of the pure or mixed plantation, characterized by the higher contents of the available N, P and K in the rhizosphere. The available N content in the rhizosphere of th e larch in mixed plantation was obviously higher than that of its pure plantatio n, whereas the available P and K contents in the rhizosphere of walnut in the mi xed plantation, on the other hand, were significantly higher than those of its p ure plantation. 展开更多
关键词 Rhizosphere soil Bulk soil Nutrient mobilization Pure and mixed plantations
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Lead anthropogenic transfer and transformation in China 被引量:1
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作者 梁静 毛建素 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第4期1262-1270,共9页
Information on lead redistribution and speciation changes in anthrosphere can help to analyze the whole lead cycle on the earth. Lead life cycle was traced based on the concepts of anthropogenic transfer and transform... Information on lead redistribution and speciation changes in anthrosphere can help to analyze the whole lead cycle on the earth. Lead life cycle was traced based on the concepts of anthropogenic transfer and transformation. Lead transfer and the distribution of chemical species throughout the anthropogenic flow were identified in 2010 in China. The results show that 1.85 Mt lead ore was consumed(besides 1.287 Mt imported concentrated ore and 1.39 Mt lead scraps. After undergoing transformations, 3.53 Mt lead entered end services in chemical species of Pb, Pb O2 and PbSO4, altogether accounting for over 80% of the total lead products. Finally, 2.10 Mt ore was emitted into the environment in such species as PbSO4(26%), PbO(19%) and Pb(15%). Lead transfer begins in primary raw material sectors, and then transfers to manufacturing sectors. Lead provides services mainly in such industrial sectors as transportation, electrical power and buildings or construction. 展开更多
关键词 lead element TRANSFER TRANSFORMATION anthrosphere REDISTRIBUTION industrial sectors chemical species life cycle
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一类Markov模型及预测问题
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作者 彭小宁 《怀化学院学报》 1995年第2期27-33,共7页
本文讨论一类推广的Markov模型,考虑一个由K类组成的系统,结出这一模型的基本方程.同时讨论在迁入率有上界时确定控制序列,使系统从初始结构尽快达到或趋于期望结构的方法.
关键词 MARKOV模型 系统结构 基本方程 控制序列 初始结构 转移概率 稳态结构 元素转移 有上限 迁入率
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All Set and Intelligent Bargaining Control Model
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作者 Liu Yang Zhangjiang Xing Lin Lai Zhibiao 《工程科学(英文版)》 2005年第3期75-80,共6页
As the rapid development of electronic commerce in our country in recent years it is becoming focus how to use electronic commerce to realize non-distant communication of E2C and E2E which is called the second generat... As the rapid development of electronic commerce in our country in recent years it is becoming focus how to use electronic commerce to realize non-distant communication of E2C and E2E which is called the second generation of electronic commerce. This paper combines the All Set theory with Matter Element transform into bargaining theory to build All Set bargaining model. In this model, the bargaining conditions of both sides are viewed as Matter Element which is the basic cell of extension theory. By using All Set theory, shell theory, fuzzy control and extension theory, the process of Matter Element transform from original Matter Element to final Matter Element which can be satisfied by both sides in bargaining is discussed. There are four axioms are distracted based on the All Set bargaining model. At last we extend our bi-persons bargaining model to multi-persons bargaining model by using soft matching system, and make it possible for intelligent bargaining on the supporting of electronic commerce. 展开更多
关键词 智能交易控制 交易定理 物质元素转移 电子商务 互联网
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关系质量对企业知识创造绩效的作用机理:一个被调节的中介模型 被引量:3
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作者 李丹 杨建君 邓程 《科技进步与对策》 CSSCI 北大核心 2021年第21期108-117,共10页
基于嵌入性视角,分别引入知识转移、合作模式作为中介变量和调节变量,深入探究关系质量影响企业知识创造绩效的内在机理。利用277份来自全国多地的制造业及高新技术企业调查问卷,采用多元回归方法进行实证研究。结果表明:经济型和社会... 基于嵌入性视角,分别引入知识转移、合作模式作为中介变量和调节变量,深入探究关系质量影响企业知识创造绩效的内在机理。利用277份来自全国多地的制造业及高新技术企业调查问卷,采用多元回归方法进行实证研究。结果表明:经济型和社会型关系质量均正向影响企业知识创造绩效;社会型关系质量通过元素知识和架构知识转移正向影响企业知识创造绩效。在契约治理模式下,经济型关系质量更倾向于通过元素知识转移正向影响企业知识创造绩效;在股权治理模式下,社会型关系质量更倾向于通过架构知识转移正向影响企业知识创造绩效。 展开更多
关键词 双边关系质量 元素知识转移 架构知识转移 企业知识创造绩效 合作模式
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Preventing Hg Transference from Soil to Terrestrial Food Chain 被引量:3
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作者 QINGCHANG-LE MOUSHU-SEN 《Pedosphere》 SCIE CAS CSCD 1993年第1期67-73,共7页
Hg in acid soil could be activited by liming and become available to plant, if excessive or insufficient amount of lime was applied. The changes of Hg activity in acid soil with different rates of CaCO3 amendment Were... Hg in acid soil could be activited by liming and become available to plant, if excessive or insufficient amount of lime was applied. The changes of Hg activity in acid soil with different rates of CaCO3 amendment Were studied by a pot experiment. To predict the adequate amount of lime application, a simple method using the pH (EDTA) as an indicator was suggested. The suitable range of lime application was the amount of lime addition when the pH of soil-EDTA system was.raised to 4.0-4.3. 展开更多
关键词 food chain MERCURY TERRESTRIAL TRANSFERENCE
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Calcium signaling and T-type calcium channels in cancer cell cycling 被引量:13
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作者 James T Taylor Xiang-Bin Zeng +6 位作者 Jonathan E Pottle Kevin Lee Alun R Wang Stephenie G Yi lennifer A S Scruggs Suresh S Sikka Ming Li 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第32期4984-4991,共8页
Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells, free calcium concentration is essential for cells to enter... Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells, free calcium concentration is essential for cells to enter and accomplish the S phase and the M phase of the cell cycle. In contrast, cancerous cells can pass these phases of the cell cycle with much lower cytoplasmic free calcium concentrations, indicating an alternative mechanism has developed for fulfilling the intracellular calcium requirement for an increased rate of DNA synthesis and mitosis of fast replicating cancerous cells. The detailed mechanism underlying the altered calcium loading pathway remains unclear; however, there is a growing body of evidence that suggests the T-type Ca2+ channel is abnormally expressed in cancerous cells and that blockade of these channels may reduce cell proliferation in addition to inducing apoptosis. Recent studies also show that the expression of T-type Ca2+ channels in breast cancer cells is proliferation state dependent, i.e. the channels are expressed at higher levels during the fast-replication period, and once the cells are in a non-proliferation state, expression of this channel isminimal. Therefore, selectively blocking calcium entry into cancerous cells may be a valuable approach for preventing tumor growth. Since T-type Ca2+ channels are not expressed in epithelial cells, selective T-type Ca2+ channel blockers may be useful in the treatment of certain types of cancers. 展开更多
关键词 T-type calcium channels CANCER CELLCYCLE CALCIUM
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企业间知识兼容性对企业知识创造绩效的影响:关系质量的调节作用
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作者 李丹 杨建君 邓程 《科技管理研究》 CSSCI 北大核心 2021年第17期126-135,共10页
整合知识基础、知识结构、知识转移和嵌入性视角,探究企业间知识兼容性对企业知识创造绩效的作用机理,利用239份来自我国制造及高新技术企业的调查问卷检验研究假设。结果表明,(1)企业间知识兼容性正向影响企业知识创造绩效。(2)元素和... 整合知识基础、知识结构、知识转移和嵌入性视角,探究企业间知识兼容性对企业知识创造绩效的作用机理,利用239份来自我国制造及高新技术企业的调查问卷检验研究假设。结果表明,(1)企业间知识兼容性正向影响企业知识创造绩效。(2)元素和架构知识转移完全中介于企业间知识兼容性与企业知识创造绩效之间。(3)经济型关系质量正向调节企业间知识兼容性与元素知识转移之间的关系,且经济型关系质量越强,企业间知识兼容性越通过元素知识转移促进企业知识创造绩效。指导合作创新参与企业发挥企业间知识和关系对自身知识创造的促发作用,借助企业间不同结构的知识转移,加速自身向知识创造型企业的转变。 展开更多
关键词 企业间知识兼容性 元素和架构知识转移 企业知识创造绩效 双边关系质量
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Direct Osmosis
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作者 Terpugov Daniil Terpugov Grigory 《Journal of Chemistry and Chemical Engineering》 2013年第9期897-900,共4页
Method of direct osmosis (also known as nonequivalent ion transfer through semipermeable membrane) was developed in 1971 and patented in 1974 by one of authors. There were no publications because the patent was secr... Method of direct osmosis (also known as nonequivalent ion transfer through semipermeable membrane) was developed in 1971 and patented in 1974 by one of authors. There were no publications because the patent was secreted. Moreover, necessary quality of membranes--high negative selectivity and apparatus for this process was provided only in 2000s (patented in 2008). Technology of direct osmosis is able to solve a number of problems of industry, such as extracting of rare elements (Re, Ge, U, etc.) from natural and manufacturing water. The authors need to mention that direct osmosis makes possible to create rentable technology of greenhouse gases trapping and burying. It will be shown in the next article. And this article is about the basic idea--nonequivalent ion transfer through semipermeable membrane or direct osmosis. 展开更多
关键词 Climate change direct osmosis oxidation-reduction potential reverse osmosis.
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Expatriation as an Element of Diversity Management
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作者 Daniel H. Scheible 《Sociology Study》 2015年第5期347-353,共7页
The ongoing internationalization of companies goes hand in hand with an increase of international assignments. With it, knowledge is transferred and diverse teams emerge in the subsidiaries abroad. However, expatriati... The ongoing internationalization of companies goes hand in hand with an increase of international assignments. With it, knowledge is transferred and diverse teams emerge in the subsidiaries abroad. However, expatriation management and diversity management have been separated areas so far. Thus, the readiness to use expatriation as an integral element of an overall diversity strategy has been evaluated in an exploratory empirical study. For this purpose, semi-structured interviews have been conducted with both expatriates and HR (human resources) managers in six subsidiaries and the headquarters of an international mechanical engineering company. It was found that operative aspects of the expatriate management dominate the viewpoint of those involved. However, the findings also suggest that an implicit recognition of advantages that stem from the variety of individual employees exists. Willingness to systematically strengthen the exchange and learning process was detected. Based on these results, a new approach could be conceptualized and implemented. This provides various foci for further research. 展开更多
关键词 EXPATRIATION diversity management human resource management organizational learning
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应急响应人员在核辐射突发事件应急救援中的辐射防护 被引量:6
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作者 吴自香 刘彦兵 +2 位作者 杨宇华 黄伟旭 吴劲松 《中国辐射卫生》 2009年第3期336-339,共4页
目的有效保护核辐射突发事件应急救援人员的身体安全,实施对应的应急救治措施。方法介绍了核辐射突发事件相关的放射防护知识。结果从辐射效应、应急工作类型、剂量控制和防护要点指导应急救援人员,采取相应的防护措施。结论应急救援人... 目的有效保护核辐射突发事件应急救援人员的身体安全,实施对应的应急救治措施。方法介绍了核辐射突发事件相关的放射防护知识。结果从辐射效应、应急工作类型、剂量控制和防护要点指导应急救援人员,采取相应的防护措施。结论应急救援人员应具备相应的放射防护知识,有效防护可降低辐射伤害。 展开更多
关键词 元素转移 土壤 膳食摄人量 全身负荷量
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Effects of Co doping on electronic structure and electric/magnetic properties of La_(0.1)Bi_(0.9)FeO_3 ceramics
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作者 WANG ShouYu FENG Yu +2 位作者 LIU WeiFang YU DaShu LI DeJun 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第10期1861-1865,共5页
In this work,we report the influence of Co-doping on the electronic band structure,dielectric and magnetic properties of La0.1Bi0.9Fe1-xCoxO3 ceramics.X-ray photoelectron spectroscopy investigation shows that Co dopan... In this work,we report the influence of Co-doping on the electronic band structure,dielectric and magnetic properties of La0.1Bi0.9Fe1-xCoxO3 ceramics.X-ray photoelectron spectroscopy investigation shows that Co dopant can shift the valence band spectrum and core-level lines of constituent elements towards higher bind energy regions simultaneously increase the concentration of oxygen vacancies in ceramics.The effects of dopant are discussed with focus given to the Co-doping induced enhancement of electrical conductivity and resistive switching phenomena. 展开更多
关键词 BIFEO3 Co doping electronic structure XPS
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Performance of Copper Calorimeter for Heat Transfer Measurement in High Enthalpy Shock Tunnel
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作者 WANG Qiu LI Jiwei +2 位作者 LI Jinping ZHAO Wei JIANG Zonglin 《Journal of Thermal Science》 SCIE EI CAS CSCD 2018年第4期373-381,共9页
Copper calorimeter, based on a calorimetric principle, offers a solution for heat transfer measurement in high enthalpy situation, especially in the erosive flow of high enthalpy shock tunnels. In this study, we numer... Copper calorimeter, based on a calorimetric principle, offers a solution for heat transfer measurement in high enthalpy situation, especially in the erosive flow of high enthalpy shock tunnels. In this study, we numerically investigated the measuring performance of copper calorimeters. Non-ideal effects, such as heat loss to the insulator around and replacement of the average temperature of the copper element by the junction temperature, were discussed in detail. The influences of copper element thickness, copper/constantan wires thickness and sensor diameter were also estimated, with the aim to provide theoretical guidance for the design of copper calorimeter. In addition, corresponding experiments in JF10 high enthalpy shock tunnel were carried out against the data of coaxial thermocouples for verification. Results showed that the non-ideal thermal environment of a copper calorimeter(heat exchange with its surroundings) would result in a smaller measuring heat flux comparing to the one actually loaded; proper thickness of copper element matching the effective test time of shock tunnel was suggested. Besides, preliminary experimental results with corrections showed reasonable agreement with the heat flux of thermocouples, with an average deviation of 8%. Over all, this gauge developed extends and supplements the high enthalpy shock tunnel heat transfer measurements made by other techniques. 展开更多
关键词 copper calorimeter high enthalpy shock tunnel heat transfer hypersonic
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