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Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon 被引量:1
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作者 David Kenfack George B Chuyong +2 位作者 Richard Condit Sabrina E Russo Duncan W Thomas 《Forest Ecosystems》 SCIE CAS 2014年第4期201-213,共13页
Background: Many tree species in tropical forests have distributions tracking local ridge-slope-valley topography. Previous work in a 50-ha plot in Korup National Park, Cameroon, demonstrated that 272 species, or 63%... Background: Many tree species in tropical forests have distributions tracking local ridge-slope-valley topography. Previous work in a 50-ha plot in Korup National Park, Cameroon, demonstrated that 272 species, or 63% of those tested, were significantly associated with topography. Methods: We used two censuses of 329,000 trees ≥1 cm dbh to examine demographic variation at this site that would account for those observed habitat preferences. We tested two predictions. First, within a given topographic habitat, species specializing on that habitat ('residents') should outperform species that are specialists of other habitats ('foreigners'). Second, across different topographic habitats, species should perform best in the habitat on which they specialize ('home') compared to other habitats ('away'). Species' performance was estimated using growth and mortality rates. Results: In hierarchical models with species identity as a random effect, we found no evidence of a demographic advantage to resident species. Indeed, growth rates were most often higher for foreign species. Similarly, comparisons of species on their home vs. away habitats revealed no sign of a performance advantage on the home habitat. Conclusions" We reject the hypothesis that species distributions along a ridge-valley catena at Korup are caused by species differences in trees _〉1 cm dbh. Since there must be a demographic cause for habitat specialization, we offer three alternatives. First, the demographic advantage specialists have at home occurs at the reproductive or seedling stage, in sizes smaller than we census in the forest plot. Second, species may have higher performance on their preferred habitat when density is low, but when population builds up, there are negative density-dependent feedbacks that reduce performance. Third, demographic filtering may be produced by extreme environmental conditions that we did not observe during the census interval. 展开更多
关键词 TREE Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon FIGURE
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Changes of Word Meaning in English-Generalization/Specialization and Pejoration/Amelioration 被引量:1
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作者 范存英 庞峰 《海外英语》 2019年第11期254-256,共3页
Changes of word meanings in English are often achieved by the processes of generalization/specialization and pejoration/amelioration.By generalization or specialization,the literal meanings of a word are broadened or ... Changes of word meanings in English are often achieved by the processes of generalization/specialization and pejoration/amelioration.By generalization or specialization,the literal meanings of a word are broadened or narrowed.While by pejoration or amelioration,the associations of a word go downhill or rise.Trough supplying certain examples,a brief picture about meaning changes of words in English is drawn. 展开更多
关键词 word MEANING GENERALIZATION specialization pejoration AMELIORATION
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Comparison of respiratory mechanics measurement between pressure-controlled ventilation and volumecontrolled ventilation
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作者 Zhi’ang Li Peifang Li +4 位作者 Yiling Jiang Jianjun Zhu Jianliang Zhu Zhiping Xu Lijun Liu 《World Journal of Emergency Medicine》 2025年第1期78-81,共4页
Mechanical ventilation is a specialized oxygen therapy and life support technology with significant importance for critically ill patients. In fact, 40%–66% of patients in the intensive care unit(ICU) require mechani... Mechanical ventilation is a specialized oxygen therapy and life support technology with significant importance for critically ill patients. In fact, 40%–66% of patients in the intensive care unit(ICU) require mechanical ventilation.^([1,2]) However, the mechanical ventilation can lead to ventilatorassociated lung injury(VALI),^([3]) ultimately resulting in difficulties in weaning from mechanical ventilation,prolonged hospital stays, and even increased mortality. 展开更多
关键词 specialized ventilation ultimately
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Nondestructive and active interrogation system for special nuclear material:proof of principle and initial results 被引量:1
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作者 Mahmoud Bakr Kai Masuda +3 位作者 Yoshiyuki Takahashi Tsuyoshi Misawa Norio Yamakawa Tomas Scott 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第5期216-225,共10页
Herein,we employ the threshold energy neutron analysis(TENA)technique to introduce the world's first active interrogation system to detect special nuclear materials(SNMs),including U-235 and Pu-239.The system util... Herein,we employ the threshold energy neutron analysis(TENA)technique to introduce the world's first active interrogation system to detect special nuclear materials(SNMs),including U-235 and Pu-239.The system utilizes a DD neutron generator based on inertial electrostatic confinement(IEC)to interrogate suspicious objects.To detect secondary neutrons produced during fission reactions induced in SNMs,a tensioned metastable fluid detector(TMFD)is employed.The current status of the system's development is reported in this paper,accompanied by the results from experiments conducted to detect 10 g of highly enriched uranium(HEU).Notably,the experimental findings demonstrate a distinct difference in the count rates of measurements with and without HEU.This difference in count rates surpasses two times the standard deviation,indicating a confidence level of more than 96% for identifying the presence of HEU.The paper presents and extensively discusses the proof-of-principle experimental results,along with the system's planned trajectory. 展开更多
关键词 Special nuclear materials Uranium detection Inertial electrostatic confinement fusion TENA HEU CTMFD
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AGGREGATE SPECIAL FUNCTIONS TO APPROXIMATE PERMUTING TRI-HOMOMORPHISMS AND PERMUTING TRI-DERIVATIONS ASSOCIATED WITH A TRI-ADDITIVEψ-FUNCTIONAL INEQUALITY IN BANACH ALGEBRAS
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作者 Safoura Rezaei ADERYANI Azam AHADI +1 位作者 Reza SAADATI Hari M.SRIVASTAVA 《Acta Mathematica Scientia》 SCIE CSCD 2024年第1期311-338,共28页
In this paper,we define a new class of control functions through aggregate special functions.These class of control functions help us to stabilize and approximate a tri-additiveψ-functional inequality to get a better... In this paper,we define a new class of control functions through aggregate special functions.These class of control functions help us to stabilize and approximate a tri-additiveψ-functional inequality to get a better estimation for permuting tri-homomorphisms and permuting tri-derivations in unital C*-algebras and Banach algebras by the vector-valued alternative fixed point theorem. 展开更多
关键词 permuting tri-homomorphism in Banach algebra permuting tri-derivation on C*-algebra fixed point theorem Ulam-Hyers-Rassias stability aggregate special functions tri-additiveψ-functional inequality
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国外学科科研绩效评估指数的文献回顾 被引量:2
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作者 单承伟 王红 +1 位作者 张苏 杨毓丽 《现代情报》 CSSCI 北大核心 2015年第11期171-177,共7页
目前很多学者利用RSI,AI,RCR,Specialization Intensity Index等指数从论文数量,引用次数,篇均引文量等指标分析某一研究国家(机构)学科排名情况。本文通过对学科科研绩效评估指数的文献回顾,分析了RSI,AI,RCR,Specialization Intensity... 目前很多学者利用RSI,AI,RCR,Specialization Intensity Index等指数从论文数量,引用次数,篇均引文量等指标分析某一研究国家(机构)学科排名情况。本文通过对学科科研绩效评估指数的文献回顾,分析了RSI,AI,RCR,Specialization Intensity Index等学科绩效评价指数的适用性和不足。研究结果表明:在开展影响力评价时,学科绩效评估不应仅仅是单一指标的比较,还应该遵循坚持同类相比的原则。 展开更多
关键词 RSI AI RCR specialization INTENSITY Index 学科评估
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荷兰观赏苗木的生产 被引量:4
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作者 张少杰 吴泽民 《中国城市林业》 2003年第3期61-65,共5页
文章介绍了荷兰在观赏苗木生产与培育方面的基本经验,如专业化的生产模式,多样化的观赏树木种类,严格的质量控制与监督、检测体系,完善的生产、管理与服务系统,以及高度重视创新等。同时,针对我国观赏苗木生产的现状提出几点建议。
关键词 NURSERY STOCK specialization VARIETY Quality INNOVATION Netherlands
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上海地区水稻土氮素矿化及其模拟 被引量:27
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作者 李慧琳 韩勇 蔡祖聪 《土壤学报》 CAS CSCD 北大核心 2004年第4期503-510,共8页
采用改进的培养方法和分析手段研究了上海地区典型水稻土淹水条件下的氮素矿化过程。结果表明矿化量为全N的 4 0 %~ 9 4 % (N 6 0~ 2 4 1mgkg-1)。通过偏相关分析 ,矿化量只表现为与全N相关。矿化期间pH变化较大且与矿化量直线相关... 采用改进的培养方法和分析手段研究了上海地区典型水稻土淹水条件下的氮素矿化过程。结果表明矿化量为全N的 4 0 %~ 9 4 % (N 6 0~ 2 4 1mgkg-1)。通过偏相关分析 ,矿化量只表现为与全N相关。矿化期间pH变化较大且与矿化量直线相关。选择 (1)有效积温式 ;(2 )一级反应式 (One pool模型 ) ;(3)两部分一级反应式 (Two pool模型 ) ;(4 )带常数项的一级反应式 (Special模型 ) ,对实验结果进行了拟合。非线性拟合表明Two pool模型和Special模型最优 ,后者体现出温度效应。通过参数分析和实际应用可能性剖析 。 展开更多
关键词 上海 水稻土 氮素 淹水矿化 模拟 Special模型 氮肥
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新疆伊宁矿区特殊地质条件液压支架选型研究 被引量:7
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作者 刘光木 张京超 +1 位作者 续文峰 任艳芳 《中国煤炭》 北大核心 2014年第2期67-70,79,共5页
介绍了伊犁4#矿井的概况,针对新疆伊宁矿区伊北煤田巨厚Ⅲ级严重湿陷性表土层、浅埋深、无关键承载层以及"三软"地质条件下厚煤层的开采等特殊地质条件,采用现场地层资料实测和实验室模拟以及类似地质条件下开采情况调研后,... 介绍了伊犁4#矿井的概况,针对新疆伊宁矿区伊北煤田巨厚Ⅲ级严重湿陷性表土层、浅埋深、无关键承载层以及"三软"地质条件下厚煤层的开采等特殊地质条件,采用现场地层资料实测和实验室模拟以及类似地质条件下开采情况调研后,对液压支架选型进行了综合分析,并确定了液压支架选型结果,为矿井实现安全高效开采乃至整个矿区煤炭资源大规模开发提供了可靠保障。 展开更多
关键词 伊宁矿区 特殊地质条件 液压支架 选型研究 SPECIAL GEOLOGICAL conditions1
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DEVELOPMENT AND PRELIMINARY APPLICATION OF OBJECTIFYING SYSTEM FOR TCM COLOR INSPECTION 被引量:2
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作者 郑冬梅 戴振东 王鸿谟 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第4期395-403,共9页
An objectifying system for color inspections of traditional Chinese medicine (CITCM) is developed. The entire system includes two parts : The hardware and the software. The hardware is an image acquiring device und... An objectifying system for color inspections of traditional Chinese medicine (CITCM) is developed. The entire system includes two parts : The hardware and the software. The hardware is an image acquiring device under a standard lighting condition, and it mainly includes a xenon lamp with color temperature of 5 500 K as light source, an integrating sphere used for diffusing light and a high resolution CCD camera. The software is used for digital image processing, and the procedure is divided into three steps. Firstly the skin/non-skin classifi- cation is performed by utilizing the threshold in chrominance channels of the RGB color space. Secondly, the fa- cial features are localized by using the image segmentation and coordinates sorting. Finally, the facial special re- gion(SR) corresponding to five internal organs is achieved by utilizing masks designed to take advantage of mor- phology. Subsequently, the chromaticity is calculated. The system is tested by taking 83 samples of 30 young and 53 elderly people. The experiment shows that there is significant difference of all SRs between the young and the elderly, and the system has better performance for objectifying research of CITCM. 展开更多
关键词 color inspection special region integrating sphere image processing CHROMATICITY significant dif- ference
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异形励磁结构稀土永磁航空直流电动机
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作者 芦刚 李声晋 +1 位作者 马瑞卿 李钟明 《西北工业大学学报》 EI CAS CSCD 北大核心 1994年第2期342-344,共3页
异形励磁结构稀土永磁航空直流电动机芦刚,李声晋,马瑞卿,李钟明和普通电励磁电机相比,稀土电机具有高效率、高功率密度、工作特性好等优点,但能否广泛应用于航空航天领域,有一系列问题尚待解决,其中较关键的问题有励磁结构的可... 异形励磁结构稀土永磁航空直流电动机芦刚,李声晋,马瑞卿,李钟明和普通电励磁电机相比,稀土电机具有高效率、高功率密度、工作特性好等优点,但能否广泛应用于航空航天领域,有一系列问题尚待解决,其中较关键的问题有励磁结构的可靠性、稀土磁钢的性能稳定性及良好的... 展开更多
关键词 special excitation slructure REPM motor.
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Spatial niche segregation between bird species in the Białowieża primeval forest(NE Poland)
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作者 Oliwia Karpińska Katarzyna Kamionka-Kanclerska +2 位作者 Patryk Czortek Marcin K.Dyderski Dorota Czeszczewik 《Forest Ecosystems》 SCIE CSCD 2023年第4期483-493,共11页
Drivers of bird niche separation in temperate primeval forests have not yet been determined,due to the low number of intact forest sites.Here,we analyzed the general patterns of niche usage on trees by birds’assembla... Drivers of bird niche separation in temperate primeval forests have not yet been determined,due to the low number of intact forest sites.Here,we analyzed the general patterns of niche usage on trees by birds’assemblages.We tested how tree species affect the sharing of space in an assemblage of birds and their level of specialization.We conducted our study in the Białowieża primeval forest(NE Poland).During two breeding seasons,we observed bird positions on trees,divided into three vertical and six horizontal zones in 768 observation points.Based on the interaction networks framework we calculated the Kullback-Leibler distance d′as a metric of species specialization and the resource range RR index,which estimates the species’specificity based on the fraction of space utilized with a non-zero performance.The d′index was the highest in the lower understory for all parts of the tree on the basis of the position from the trunk.The RR index was the highest in the lower understory for all parts based on the position from the trunk.Regarding the tree species,the lowest d′index was observed in all tree species together,and hornbeam,whereas the highest in oak.At the tree species level,the RR index was the lowest for hornbeam.We show tree species importance in forest space sharing in the case of bird assemblages.Hornbeam,alder,and spruce are universal species that were used by birds almost entirely.In contrast,oak,lime,and maple were only partially used.Tree species with less complex structures could shape bird assemblages,as they could offer birds much fewer niches to realize.Therefore,we showed that high specialization and niche separation are drivers of high bird diversity.Consequently maintaining a diverse stand structure is crucial for biodiversity conservation. 展开更多
关键词 Tree use Niche partitioning Foraging guild specialization Habitat filtering Foundation species Tree species effect
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Designing an EGP+ESP merging Curriculum for Technical Vocational College Students
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作者 韦鸿发 《海外英语》 2012年第4X期101-102,104,共3页
The English curriculum in vocational colleges must stress the practical and professional characteristics.This concept should be conducted throughout the entire teaching process,but not just some of the teaching stages... The English curriculum in vocational colleges must stress the practical and professional characteristics.This concept should be conducted throughout the entire teaching process,but not just some of the teaching stages.By analysis of the curriculum goals and context of vocational colleges,based on theories of ESP,needs analysis,and experimental research,this article intends to prove the rationality and necessity of the curriculum pattern for non-English majors of vocational colleges by merging ESP into EGP which emphasizing communication as the basic and job orientation as the guidance. 展开更多
关键词 ESP(English for SPECIAL Purposes) EGP(English for
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ESPNeeds Analysisand Course Designin Application-Oriented Universities
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作者 王晓芳 《海外英语》 2018年第6期236-237,共2页
With demands for applied talents dramatically increasing motivated by economic transformation and China's "Going Out " Strategy, College English reform should deepen ESP teaching, stress application of l... With demands for applied talents dramatically increasing motivated by economic transformation and China's "Going Out " Strategy, College English reform should deepen ESP teaching, stress application of language skills to academic and professionallearning, and serve for students' future development. Therefore, it is vital to explore school-based course design in ESP based onneeds analysis. 展开更多
关键词 English for Special Purposes needs analysis school-based course design
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World Literature in Modern Times
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作者 谭昶 《海外英语》 2019年第2期204-205,共2页
The literary and cultural centre and the periphery seek the energy from its counterpart,which breaks the chain of fixing one knowledge in one special field studies.Thus,this paper will illustrate Auerbach’s statement... The literary and cultural centre and the periphery seek the energy from its counterpart,which breaks the chain of fixing one knowledge in one special field studies.Thus,this paper will illustrate Auerbach’s statement about the further potential development of world literature.Also the ways scholars are devoted to overcoming the knowledge of specialization from Auerbach’s aspect of Weltliteratur serve as an Ansatzpunkt will be discussed. 展开更多
关键词 MODERNISM specialization Auerbach world LITERATURE
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花园深圳 再创未来 深圳特区风景园林创新发展论坛 被引量:2
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作者 陈晓丽 孟兆祯 +16 位作者 蔡灜 宋建春 姚宝隆 刘榕 杨赉丽 唐学山 吴家骅 周远松 丁少江 李勇 梁正阳 朱伟华 王晓明 王定跃 何昉 李翠筠 陈永清 《风景园林》 2010年第6期18-25,共8页
深圳风景园林30年的发展历程,也是现代风景园林改革实践的过程。从继承和发扬近三千年传统的风景园林艺术,到率先尝试完善新时代的中国风景园林体系,深圳风景园林为深圳这座年轻的"设计之都"描就重彩。在上一期的杂志中,我们... 深圳风景园林30年的发展历程,也是现代风景园林改革实践的过程。从继承和发扬近三千年传统的风景园林艺术,到率先尝试完善新时代的中国风景园林体系,深圳风景园林为深圳这座年轻的"设计之都"描就重彩。在上一期的杂志中,我们推出了"深圳特区风景园林30年"专题,追忆了改革开放以来深圳风景园林建设的峥嵘岁月与卓越成就,同时也以前海开发和绿道建设为契机,展示深圳建设宜居城市的决心和信心。然而,随着经济社会发展进入了新阶段,深圳的城市建设及风景园林建设也面临诸多难题,面对未来发展,胡锦涛同志勉励深圳"要适应国内外形势新变化、按照国家发展新要求、顺应人民新期待","要努力当好推动科学发展、促进社会和谐的排头兵"。深圳任重道远,深圳城市与风景园林亦然。为此,11月27日,《风景园林》杂志社与深圳市城管局精心策划,共同举办"花园深圳、再创未来——深圳城乡风景园林创新发展论坛",诚邀内地、香港和澳门的知名专家学者齐聚一堂,畅怀交流,共同探索深圳未来创新发展之路。每位专家和嘉宾的发言都非常精彩,对深圳满含深情和期望,我们撷取其精华,以飨读者。 展开更多
关键词 花园 深圳特区 风景园林 创新发展 论坛 Special LANDSCAPE Development CREATIVE 世界大学生运动会 绿道建设 珠三角 深圳经济特区 改革开放 总书记 主持人 亚运会 三角和 国家级 陈晓丽
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Carbon-Based MOF Derivatives:Emerging Efficient Electromagnetic Wave Absorption Agents 被引量:21
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作者 Xue Zhang Jing Qiao +6 位作者 Yanyan Jiang Fenglong Wang Xuelei Tian Zhou Wang Lili Wu Wei Liu Jiurong Liu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2021年第9期105-135,共31页
To tackle the aggravating electromagnetic wave(EMW)pollution issues,high-efficiency EMW absorption materials are urgently explored.Metal-organic framework(MOF)derivatives have been intensively investigated for EMW abs... To tackle the aggravating electromagnetic wave(EMW)pollution issues,high-efficiency EMW absorption materials are urgently explored.Metal-organic framework(MOF)derivatives have been intensively investigated for EMW absorption due to the distinctive components and structures,which is expected to satisfy diverse application requirements.The extensive developments on MOF derivatives demonstrate its significantly important role in this research area.Particularly,MOF derivatives deliver huge performance superiorities in light weight,broad bandwidth,and robust loss capacity,which are attributed to the outstanding impedance matching,multiple attenuation mechanisms,and destructive interference effect.Herein,we summarized the relevant theories and evaluation methods,and categorized the state-of-the-art research progresses on MOF derivatives in EMW absorption field.In spite of lots of challenges to face,MOF derivatives have illuminated infinite potentials for further development as EMW absorption materials. 展开更多
关键词 Carbon-based MOF derivatives Special structures Multiple attenuation mechanisms Impedance matching EMW absorption
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Three Kinds of Special Relativity via Inverse Wick Rotation 被引量:4
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作者 郭汉英 黄超光 +1 位作者 徐湛 周彬 《Chinese Physics Letters》 SCIE CAS CSCD 2005年第10期2477-2480,共4页
Since the special relativity can be viewed as the physics in an inverse Wick rotation of four-dimensional (4D) Euclid space, which is at almost equal footing with the 4D Riemann/Lobachevski space, there should be im... Since the special relativity can be viewed as the physics in an inverse Wick rotation of four-dimensional (4D) Euclid space, which is at almost equal footing with the 4D Riemann/Lobachevski space, there should be important physics in the inverse Wick rotation of 4D Riemann/Lobachevski space. Thus, there are three kinds of special relativity in de Sitter(dS)/Minkowski/anti-de Sitter(AdS) space at almost equal footing, respectively. There is an instanton tunnelling scenario in the Riemann-de Sitter case that may explain why A be positive and link with the multiverse. 展开更多
关键词 INVARIANT SPECIAL RELATIVITY SITTER SPACETIME SUPERGRAVITY CONSTANT GRAVITY
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Theoretical Investigation on Vertical Additional Force on Shaft Lining in Special Stratum 被引量:3
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作者 杨维好 付厚利 《International Journal of Mining Science and Technology》 SCIE EI 1999年第2期129-135,共7页
The model of skaft lining under force is developed on the basis of the special stratum condition led to sbart cracking- The model is broken into 3 sub-questions to solve separately. According to the principle of super... The model of skaft lining under force is developed on the basis of the special stratum condition led to sbart cracking- The model is broken into 3 sub-questions to solve separately. According to the principle of superposition and strain compatibility, a second kind Fredholm integral equation is generated.A theoretical solution to vertical additional force on shaft lining is obtained by numerical method to the integral equation. 展开更多
关键词 SHAFT LINING VERTICAL additional force SPECIAL STRATA
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Filtration Structure of Finite-Dimensional Special Odd Hamiltonian Superalgebras in Prime Characteristic 被引量:5
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作者 何英华 刘文德 李彬 《Journal of Beijing Institute of Technology》 EI CAS 2009年第4期488-491,共4页
The filtration structure of finite-dimensional special odd Hamilton superalgebras over a field of prime characteristic was studied. By determining ad-nilpotent dements in the even part, the natural filtration of speci... The filtration structure of finite-dimensional special odd Hamilton superalgebras over a field of prime characteristic was studied. By determining ad-nilpotent dements in the even part, the natural filtration of special odd Hamiltonian superalgebras is proved to be invariant. Using this result, the special odd Hamilton superalgebras is classified. Finally, the automorphism group of the restricted special odd Hamilton superalgebras is determined. 展开更多
关键词 finite-dimensional special odd Hamilton superalgebras ad-nilpotent elements FILTRATION
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