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暂态稳定视角下的强关联输电断面及其识别方法 被引量:6
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作者 方勇杰 崔晓丹 《电力系统自动化》 EI CSCD 北大核心 2019年第5期75-82,共8页
多个交流输电断面暂态稳定极限功率相互耦合,给电网安全稳定运行控制带来了极大挑战。文中深入挖掘受扰系统中暂态响应轨迹特征与稳定模式的对应关系,提出了暂态稳定视角下关键输电断面及关联断面的概念,并将关联输电断面分为模式共存... 多个交流输电断面暂态稳定极限功率相互耦合,给电网安全稳定运行控制带来了极大挑战。文中深入挖掘受扰系统中暂态响应轨迹特征与稳定模式的对应关系,提出了暂态稳定视角下关键输电断面及关联断面的概念,并将关联输电断面分为模式共存机理决定的关联断面和模式演化机理决定的关联断面两类。提出了基于电网电气量变化来反映系统稳定模式的支路同步力系数指标,并结合该指标、图论和暂态稳定模式识别方法,提出了关键断面及关联断面识别的实用算法,有利于克服人工经验方法中因机理分析不足而可能导致的识别不准和效率低下的缺陷,为基于输电断面准确识别的稳定分析或运行监控提供了基础。基于IEEE 10机39节点系统的算例阐明了所提方法的原理及有效性。 展开更多
关键词 暂态稳定 输电断面 关联断面 模式共存 模式演化 极限功率耦合
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九种维管植物水力性状的演化趋势 被引量:2
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作者 赵乐文 陈梓熠 +8 位作者 邹滢 付子钊 吴桂林 刘小容 罗琦 林忆雪 李雄炬 刘智通 刘慧 《植物生态学报》 CAS CSCD 北大核心 2018年第2期220-228,共9页
维管植物从蕨类植物、裸子植物到被子植物的演化过程中,生理结构和功能都被认为更趋向于适应干旱的环境。但是关于3类植物是否提升了水分传导和水分利用效率的研究目前多基于叶脉和气孔的形态结构推断,而对水分传导速率的直接测量则集... 维管植物从蕨类植物、裸子植物到被子植物的演化过程中,生理结构和功能都被认为更趋向于适应干旱的环境。但是关于3类植物是否提升了水分传导和水分利用效率的研究目前多基于叶脉和气孔的形态结构推断,而对水分传导速率的直接测量则集中于被子植物内部。因此,同时测定3类植物叶片和枝条尺度的水力性状,可以研究维管植物水力性状的演化趋势和协同演化关系。该研究测定了中国科学院华南植物园内的蕨类植物(芒萁(Dicranopteris pedata)、华南毛蕨(Cyclosorus parasiticus)、乌毛蕨(Blechnum orientale)),裸子植物(罗汉松(Podocarpus macrophyllus)、竹柏(Podocarpus nagi)、落羽杉(Taxodium distichum))和被子植物(海南木莲(Manglietia fordiana var.hainanensis)、东京油楠(Sindora tonkinensis)、羊蹄甲(Bauhinia purpurea))共9种植物的水力结构与功能的相关性状。发现9种植物从原始到更演化物种的枝条比导水率(K_S)、叶片比导水率(K_L)和叶片水力导度(K_(leaf))依次升高;叶片蒸腾速率(E)和潜在水分利用效率(WUEi)升高趋势不显著;气孔面积指数(SPI)和木材密度(WD)在3个类群间无明显变化趋势。水力功能性状在枝条(K_S)和叶片(K_L、K_(leaf)和E)尺度显著相关,但和两个结构性状并无显著相关性。对显著相关的性状进行系统发育独立差分析发现相关性依然存在,表明枝条导水和叶片导水、叶片失水的协同性独立于系统发育而存在。该文以9种维管植物为例,发现演化过程中水分传导相关的功能性状有显著提升,且导水和失水的性状存在着协同演化关系。上述维管植物水力性状演化趋势的结论需要对更多物种、更精细的水力结构性状的进行测定验证。 展开更多
关键词 功能性状 适应性 水分传导 系统发育独立差 协同演化
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采用关联进化策略的RWCE算法应用于换热网络优化 被引量:1
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作者 李万总 崔国民 +1 位作者 孙涛 赵兵涛 《热能动力工程》 CAS CSCD 北大核心 2020年第2期18-25,共8页
换热单元之间的耦合关系导致其在优化过程中相互制约,造成强制进化随机游走算法应用于换热网络时后期优化停滞。因此,提出一种关联进化策略实现换热单元间的联动进化。首先对换热网络中换热单元的关联关系进行了分析,评估了这种关联关... 换热单元之间的耦合关系导致其在优化过程中相互制约,造成强制进化随机游走算法应用于换热网络时后期优化停滞。因此,提出一种关联进化策略实现换热单元间的联动进化。首先对换热网络中换热单元的关联关系进行了分析,评估了这种关联关系对进化算法的制约及效率的影响;在此基础上,建立了关联换热单元的联动进化机制,克服了优化过程中的关联制约,提升了进化的效率。最后,将采用单元关联进化策略的算法应用于15SP、16SP2算例,分别得到了年综合费用(TAC)为1513253和6849252$/a的结果,其中15SP算例的TAC较文献最优结果下降了5715$/a,验证了改进后的算法能有效地提高搜索质量。 展开更多
关键词 换热网络优化 耦合 关联进化
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Divergence and correlated evolution of male wing spot and courtship display between Drosophila nepalensis and D.trilutea
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作者 Wen-Zhou Mo Zhuo-Miao Li +6 位作者 Xiang-Mei Deng Ai-Li Chen Michael G.Ritchie De-Jun Yang Zhuo-Bin He Masanori J.Toda Shuo-Yang Wen 《Insect Science》 SCIE CAS CSCD 2022年第5期1445-1460,共16页
Male-specific wing spots are usually associated with wing displays in the courtship behavior of Drosophila and may play important roles in sexual selection.Two closely related species,D.nepalensis and D.trilutea,diffe... Male-specific wing spots are usually associated with wing displays in the courtship behavior of Drosophila and may play important roles in sexual selection.Two closely related species,D.nepalensis and D.trilutea,differ in wing spots and scissoring behavior.Here,we compare male morphological characters,pigmentation intensity of male wing spots,wing-scissoring behavior,courtship songs,and reproductive isolation between 2 species.F1 fertile females and sterile males result from the cross between females of D.nepalensis and males of D.trilutea.The pigmentation of wing spots is significantly weaker in D.trilutea than in D.nepalensis and the F1 hybrid.Males scissor both wings in front of the female during courtship,with a posture spreading wings more widely,and at a faster frequency in D.nepalensis than in D.trilutea and the F1s.Males of D.trilutea vibrate wings to produce 2 types(A and B)of pulse songs,whereas D.nepalensis and the F1s sing only type B songs.The incidence of wing vibration and scissoring during courtship suggests that wing vibration is essential but scissoring is a facultative courtship element for successful mating in both species.The association between the darker wing spots with more elaborate scissoring might be the consequence of correlated evolution of these traits in D.nepalensis;however,D.trilutea retains wing scissoring during courtship despite having weaker pigmentation of wing spots.The genetic architecture of 2 traits differs in the F1s,consistent with maternal or sex-linked effects for spots but nonadditive effects for scissoring. 展开更多
关键词 correlated evolution courtship song Drosophila nepalensis Drosophila trilutea wing display wing spot
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一种低复杂度的基于进化策略的自适应运动估计方法
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作者 王辉 毛志刚 《中国图象图形学报》 CSCD 北大核心 2005年第7期878-883,共6页
为了进一步提高编码质量并能快速编码,提出了一种新的基于进化策略的自适应运动估计算法。鉴于在进化策略中变异操作与正态分布法则对应,是核心算子,为此将进化策略应用于运动估计,提出了一种新的自适应运动估计算法,并第1次将运动方向... 为了进一步提高编码质量并能快速编码,提出了一种新的基于进化策略的自适应运动估计算法。鉴于在进化策略中变异操作与正态分布法则对应,是核心算子,为此将进化策略应用于运动估计,提出了一种新的自适应运动估计算法,并第1次将运动方向信息作为变量引入运动估计算法,同时改进了步长自适应控制机制,以便进一步提高算法的收敛速率,同时采用种群规模的自适应控制,降低了算法的复杂度。试验结果表明,该算法的性能与全搜索算法相近,而复杂度略大于三步法。由于其具有低复杂度和进化算法的内在并行性的特点,故该算法适合硬件实现。 展开更多
关键词 运动估计 相关变异 进化策略 1/5规则
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酿酒酵母进级进化过程中的基因丢失现象初探
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作者 朱新宇 《生命科学研究》 CAS CSCD 2003年第2期139-143,共5页
酿酒酵母进级进化过程中的基因丢失问题很少被研究.利用现有的蛋白质数据库,通过设定判断标准,预期可以获得更多这方面的案例以便进行相关问题的研究.利用SMART蛋白质域家族数据库,根据在已完成测序的7种真核生物蛋白质域家族成员中存... 酿酒酵母进级进化过程中的基因丢失问题很少被研究.利用现有的蛋白质数据库,通过设定判断标准,预期可以获得更多这方面的案例以便进行相关问题的研究.利用SMART蛋白质域家族数据库,根据在已完成测序的7种真核生物蛋白质域家族成员中存在或不存在酿酒酵母蛋白质域信号,判断是否发生了基因丢失.通过这种方法,共有6个酿酒酵母基因判断为在进级进化过程中发生了丢失,还探讨了这些基因发生丢失的可能机制. 展开更多
关键词 酿酒酵母 进级进化 基因丢失 关联进化
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国外政府数据开放研究的主题关联结构与演化态势 被引量:4
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作者 朱晓峰 葛锐 蒋勋 《情报科学》 CSSCI 北大核心 2022年第1期109-120,共12页
【目的/意义】数字时代"开放政府数据"热潮产出了丰硕成果,对其研究主题结构和演化脉络进行全面、精准的可视化揭示,有助于进一步丰富和完善该领域研究,科学地指导我国实践开展。【方法/过程】以2000-2019年WOS数据库中"... 【目的/意义】数字时代"开放政府数据"热潮产出了丰硕成果,对其研究主题结构和演化脉络进行全面、精准的可视化揭示,有助于进一步丰富和完善该领域研究,科学地指导我国实践开展。【方法/过程】以2000-2019年WOS数据库中"开放政府数据"主题文献为基础,借助新型SLM算法探测主题社区,梳理研究主题分布;同时嵌入SNA方法,引入"传导率"指标定量评估主题社区成熟度和内外部关联,并利用Cortext平台构建时序演进过程。【结果/结论】国外开放政府数据研究已形成四类主题社区:健康社区、开放数据社区、管理社区以及安全社区,目前仍存在"主题遍布粒度不够细化、新兴主题社区亟需成长、演化脉络断续明显"等问题。【创新/局限】嵌入新型算法SLM划分主题社区,结合LDA模型对国外OGD研究主题关联与演化进行了完整阐释。但本文仅选取WOS核心库的相关主题文献作为数据源,存在进一步扩充的空间。 展开更多
关键词 开放政府数据 主题关联结构 社会网络分析(SNA) 演化态势 数据开放
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塔里木盆地东南缘安南坝地区镁铁质麻粒岩的成因--来自地球化学及Sr-Nd-Pb同位素的制约 被引量:2
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作者 辜平阳 徐学义 +5 位作者 何世平 陈锐明 庄玉军 赵慧博 查方勇 郭亚鹏 《岩石矿物学杂志》 CAS CSCD 北大核心 2018年第5期811-823,共13页
甘肃阿克塞县安南坝地区镁铁质麻粒岩呈脉状、透镜状赋存于新太古代米兰岩群和TTG片麻岩中。岩石主要由斜长石(Pl)+斜方辉石(Opx)+单斜辉石(Cpx)+角闪石(Amp)+磁铁矿(Mt)等组成。安南坝镁铁质麻粒岩中Ti、P、Nb、Ta、Th、Hf、Sr及REE等... 甘肃阿克塞县安南坝地区镁铁质麻粒岩呈脉状、透镜状赋存于新太古代米兰岩群和TTG片麻岩中。岩石主要由斜长石(Pl)+斜方辉石(Opx)+单斜辉石(Cpx)+角闪石(Amp)+磁铁矿(Mt)等组成。安南坝镁铁质麻粒岩中Ti、P、Nb、Ta、Th、Hf、Sr及REE等元素与Zr相关性较好,表明其在变质作用过程中保持基本稳定。地球化学数据显示其原岩属于拉斑玄武质岩系列,Si O_2、Ti O_2、Al_2O_3、P_2O_5含量相对较低,Ca O、Mg O含量相对较高。Mg~#值为41.52~43.09,低于原生玄武质岩石的Mg~#值,Fe_2O_3~T、Mg O、Ca O与Si O_2含量呈负相关性,指示原岩岩浆演化过程中可能发生了辉石、角闪石等镁铁质矿物的分异结晶作用。镁铁质麻粒岩∑REE较低,稀土元素配分模式为轻稀土元素弱富集、重稀土元素相对平坦的右倾型,Eu异常不明显(Eu/Eu~*=0.91~1.01)。岩石富集Rb、Ba、Sr等大离子亲石元素,亏损Nb、Ta、Zr、Ti等高场强元素,具有显生宙典型岛弧玄武质岩石的地球化学特征。Sr、Nd、Pb同位素组成显示镁铁质麻粒岩原岩源自富集地幔,并受到一定程度的地壳物质混染。构造环境分析表明安南坝镁铁质麻粒岩原岩形成于与俯冲有关的岛弧环境。在俯冲作用机制下,俯冲板片流体交代使地幔楔发生富集,形成富集地幔,随着(弧后)伸展作用的加强,进一步诱发富集地幔的部分熔融形成镁铁质岩浆,最终岩浆就位形成辉长岩或辉绿岩脉,后期在麻粒岩相变质作用条件下变质为镁铁质麻粒岩。 展开更多
关键词 镁铁质麻粒岩 地球化学 SR-ND-PB同位素 安南坝地区 塔里木东南缘
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Detrital zircon geochronology of the Lutzow-Holm Complex,East Antarctica:Implications for Antarctica-Sri Lanka correlation 被引量:6
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作者 Yusuke Takamura Toshiaki Tsunogae +1 位作者 M.Santosh Yukiyasu Tsutsumi 《Geoscience Frontiers》 SCIE CAS CSCD 2018年第2期355-375,共21页
The Lützow-Holm Complex(LHC) of East Antarctica has been regarded as a collage of Neoarchean(ca.2.5 Ga), Paleoproterozoic(ca. 1.8 Ga), and Neoproterozoic(ca. 1.0 Ga) magmatic arcs which were amalgamated through t... The Lützow-Holm Complex(LHC) of East Antarctica has been regarded as a collage of Neoarchean(ca.2.5 Ga), Paleoproterozoic(ca. 1.8 Ga), and Neoproterozoic(ca. 1.0 Ga) magmatic arcs which were amalgamated through the latest Neoproterozoic collisional events during the assembly of Gondwana supercontinent. Here, we report new geochronological data on detrital zircons in metasediments associated with the magmatic rocks from the LHC, and compare the age spectra with those in the adjacent terranes for evaluating the tectonic correlation of East Antarctica and Sri Lanka. Cores of detrital zircon grains with high Th/U ratio in eight metasediment samples can be subdivided into two dominant groups:(1) late Meso-to Neoproterozoic(1.1-0.63 Ga) zircons from the northeastern part of the LHC in Prince Olav Coast and northern Soya Coast areas, and(2) dominantly Neoarchean to Paleoproterozoic(2.8-2.4 Ga) zircons from the southwestern part of the LHC in southern Lutzow-Holm Bay area. The ca.1.0 Ga and ca. 2.5 Ga magmatic suites in the LHC could be proximal provenances of the detrital zircons in the northeastern and southwestern LHC, respectively. Subordinate middle to late Mesoproterozoic(1.3-1.2 Ga) detrital zircons obtained from Akarui Point and Langhovde could have been derived from adjacent Gondwana fragments(e.g., Rayner Complex, Eastern Ghats Belt). Meso-to Neoproterozoic domains such as Vijayan and Wanni Complexes of Sri Lanka, the southern Madurai Block of southern India, and the central-western Madagascar could be alternative distal sources of the late Meso-to Neoproterozoic zircons. Paleo-to Mesoarchean domains in India, Africa, and Antarctica might also be distal sources for the minor ~2.8 Ga detrital zircons from Skallevikshalsen. The detrital zircons from the Highland Complex of Sri Lanka show similar Neoarchean to Paleoproterozoic(ca. 2.5 Ga) and Neoproterozoic(ca. 1.0 Ga) ages, which are comparable with those of the LHC, suggesting that the two complexes might have formed under similar tectonic regimes. We consider 展开更多
关键词 The northern Lützow-Holm-Vijayan Complex Zircon U-Pb geochronology Crustal evolution Tectonic correlations Gondwana supercontinent
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Quantum nonlocality evolution for two entangled mesoscopic fields under decoherence
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作者 Zhao-Song Tan Shou-Bang Yang +1 位作者 Zhen-Biao Yang Shi-Biao Zheng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2024年第1期24-28,共5页
Investigation of the nonlocality evolution of entangled mesoscopic fields under decoherence not only is important for understanding the quantum–classical transition,but also has relevance to quantum communication and... Investigation of the nonlocality evolution of entangled mesoscopic fields under decoherence not only is important for understanding the quantum–classical transition,but also has relevance to quantum communication and quantum computation protocols based on continuous variables.According to previous formulations of Bell inequalities,the system loses nonlocal features far before the disappearance of entanglement.We here construct a new version of Bell signal based on rotated and displaced on–off correlations,with which the Bell inequality is violated as long as there remains entanglement and the field state components keep quasiorthogonal.Consequently,the nonlocal character revealed by our formulation decays much slower compared with those based on previous ones.More importantly,there exists a wide regime where the Bell inequality is restored with previous formulations but remains to be violated based on our correlation operators. 展开更多
关键词 entangled mesoscopic fields rotated and displaced on-off correlations Bell inequality nonlocality evolution
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旅游学分支学科相关性及其进展态势分析——《旅游研究纪事》30年 被引量:5
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作者 邢珏珏 李业锦 +1 位作者 吴必虎 齐莉娜 《人文地理》 CSSCI 北大核心 2006年第1期51-55,共5页
本文按照旅游学的十个分支学科,对1973-2003年国际旅游学界权威学术刊物《旅游研究纪事》(Annals of Tourism Research)的《主题词索引》(Sub-ject Index)进行了多元相关分析和聚类分析,阐述了这十个分支学科与整个旅游学以及相互之间... 本文按照旅游学的十个分支学科,对1973-2003年国际旅游学界权威学术刊物《旅游研究纪事》(Annals of Tourism Research)的《主题词索引》(Sub-ject Index)进行了多元相关分析和聚类分析,阐述了这十个分支学科与整个旅游学以及相互之间的相关性,并分别探讨了这十个分支学科各自的进展态势。 展开更多
关键词 ANNALS of Toudsm RESEARCH 主题词索 相关性分析 聚类分析 进展态势
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Redshift Independence of the Amati and Yonetoku Relations for Gamma-Ray Bursts 被引量:2
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作者 Walid J. Azzam Mohamed J. Alothman 《International Journal of Astronomy and Astrophysics》 2013年第4期372-375,共4页
The Amati and Yonetoku relations are two of the main energy and luminosity correlations that currently exist for gamma-ray bursts (GRBs). The Amati relation is a correlation between the intrinsic peak energy, Epeak, i... The Amati and Yonetoku relations are two of the main energy and luminosity correlations that currently exist for gamma-ray bursts (GRBs). The Amati relation is a correlation between the intrinsic peak energy, Epeak, in the vFv spectrum of a burst and its equivalent isotropic energy, Eiso. The Yonetoku relation is a correlation between Epeak and the isotropic peak luminosity, Liso. In this paper, we use a recent data sample of 65 GRBs to investigate whether these two relations evolve with redshift, z. The z-correction and the?k-correction are both taken into account. Our method consists of binning the data in redshift, z, then applying (for each bin) a fit of the form:?log(Eiso) = A + Blog(Epeak/Epeak>) for the Amati relation, and of the form:?log(Liso) = A + Blog(Epeak/Epeak>) for the Yonetoku relation, where Epeak> is the mean value of the peak energy for the entire sample. The objective is to see whether the two fitting parameters, A and B, evolve systematically with z. Good least-squares fits were obtained with reasonable values for the linear regression coefficient, r. Our results indicate that the normalization, A, and the slope, B, do not evolve with redshift, and hence the Amati and Yonetoku relations seem to be redshift independent. 展开更多
关键词 GAMMA-RAY BURSTS Energy correlations LUMINOSITY Indicators REDSHIFT evolution
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Pollinator-dependent evolution of floral trait combinations in an orchid herb 被引量:1
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作者 Yun Wu Xu-Yu Duan +4 位作者 Yong Xiang Shao-Bin Weng Jin-Yu Zhong Jing Li Qing-Jun Li 《Journal of Plant Ecology》 SCIE CSCD 2020年第4期450-459,共10页
Aims As one of the most important agents driving floral evolution,pollinators shape the diversity of flowers in angiosperms.However,most previous studies have only quantified pollinators driving the evolution of a sin... Aims As one of the most important agents driving floral evolution,pollinators shape the diversity of flowers in angiosperms.However,most previous studies have only quantified pollinators driving the evolution of a single floral trait,and experimental estimates of the potential role of pollinators in shaping the evolution of floral trait associations are relatively rare.Methods We experimentally identified and estimated the pollinator-mediated directional and correlational selection on single floral traits and trait combinations across 2 years in an orchid species,Spiranthes sinensis.Important Findings Pollinators mediated directional selection for an earlier flowering start date and larger corolla size.Pollinators mediated positive correlational selection on the combinations of floral display traits and negative correlational selection on the combinations of flowering phenology and floral display traits.In addition,the strength of selection differed over time.Our results highlight the potential role of pollinators in driving the evolution of floral trait combinations and suggest that it is necessary to consider floral character functional associations when seeking to understand and predict the evolutionary trajectory of flowers in angiosperms. 展开更多
关键词 directional and correlational selection floral evolution pollinator-mediated selection Spiranthes sinensis trait combinations
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Quantum Correlations Evolution Asymmetry in Quantum Channels
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作者 李萌 黄运锋 郭光灿 《Communications in Theoretical Physics》 SCIE CAS CSCD 2017年第3期267-272,共6页
It was demonstrated that the entanglement evolution of a specially designed quantum state in the bistochastic channel is asymmetric. In this work, we generalize the study of the quantum correlations, including entangl... It was demonstrated that the entanglement evolution of a specially designed quantum state in the bistochastic channel is asymmetric. In this work, we generalize the study of the quantum correlations, including entanglement and quantum discord, evolution asymmetry to various quantum channels. We found that the asymmetry of entanglement and quantum discord only occurs in some special quantum channels, and the behavior of the entanglement evolution may be quite different from the behavior of the quantum discord evolution. To quantum entanglement, in some channels it decreases monotonously with the increase of the quantum channel intensity. In some other channels, when we increase the intensity of the quantum channel, it decreases at first, then keeps zero for some time, and then rises up. To quantum discord, the evolution becomes more complex and you may find that it evolutes unsmoothly at some points. These results illustrate the strong dependence of the quantum correlations evolution on the property of the quantum channels. 展开更多
关键词 quantum information processing quantum correlations evolution asymmetry various quantum channels
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Correlations of the Evolution of a CCOPE Squall Line with Surface Thermodynamics and Kinematic Fields
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作者 徐玉貌 J.C.Fankhauser 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1989年第1期99-112,共14页
A midlatitude squall line passed over the array of the Cooperative Convective Precipitation Experiment (CCOPE) on 1 August 1981. The structure and evolution of the squall line, and the correlations of the storm with s... A midlatitude squall line passed over the array of the Cooperative Convective Precipitation Experiment (CCOPE) on 1 August 1981. The structure and evolution of the squall line, and the correlations of the storm with surface thermodynamics and kinematic fields are investigated, mainly by using radar and surface mesonet data in CCOPE. The storm-wide precipitation efficiency is also estimated.The squall line was of an obvious process of metabolism. Thirty-four cells formed successively in front of the primary storm and eventually merged into it during the period 1700-2010 MDT. The newest cells formed near surface equivalent potential temperature maxima, and near surface moisture flux convergence zones or / and the 'temperature break lines'. The thunderstorm rainfall, with the precipitation efficiency of 54%, lags 25-30 min behind the moisture flux convergence on the average. 展开更多
关键词 MDT correlations of the evolution of a CCOPE Squall Line with Surface Thermodynamics and Kinematic Fields
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基于系统论的农村居民点用地演变驱动机制研究——以北京市昌平区为例 被引量:21
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作者 苏高华 陈方正 郑新奇 《水土保持研究》 CSCD 北大核心 2009年第4期117-120,126,共5页
我国农村居民点扩张形势十分严峻,开展其驱动机制的研究进而对农村居民点用地进行调控显得至关重要,但目前有关研究较少。基于系统论思想,采用灰色关联分析模型对北京市昌平区2001-2006年期间农村居民点用地扩张演变的驱动机制进行分析... 我国农村居民点扩张形势十分严峻,开展其驱动机制的研究进而对农村居民点用地进行调控显得至关重要,但目前有关研究较少。基于系统论思想,采用灰色关联分析模型对北京市昌平区2001-2006年期间农村居民点用地扩张演变的驱动机制进行分析研究。结果表明:二、三产业以及农业人口因素是研究区农村居民点用地扩张的主要驱动力。研究认为农村居民点用地的适度集约化调整应考虑其演变与驱动影响因素之间的动态平衡。 展开更多
关键词 系统论 灰色关联分析 农村居民点用地 演变 驱动机制
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再生剂-废旧沥青界面铺展润湿与扩散融合性能评价 被引量:1
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作者 陈龙 陈宏斌 +2 位作者 李朋 赵瑜隆 黄智德 《公路》 北大核心 2021年第10期1-9,共9页
分别采用液滴形态分析仪(DSA)和旋转剪切流变仪(DSR),针对不同作用温度、作用时间施加下的再生剂-废旧沥青界面铺展润湿行为和界面扩散融合特征进行量化评价,并建立二者性能演化的相关方程。结果表明:随作用温度逐步升高,再生剂-废旧沥... 分别采用液滴形态分析仪(DSA)和旋转剪切流变仪(DSR),针对不同作用温度、作用时间施加下的再生剂-废旧沥青界面铺展润湿行为和界面扩散融合特征进行量化评价,并建立二者性能演化的相关方程。结果表明:随作用温度逐步升高,再生剂-废旧沥青界面作用形式呈浸湿状态并趋向铺展,界面接触角δ逐级递减;自由能Wb先增后降,峰值点对应的温度范围在55~65℃区间;润湿速度V和融合速率DS呈线性函数增长,融合程度DOB呈抛物线增长并最终趋于稳定;短期老化废旧沥青Wb值和V值分别是长期老化废旧沥青的1.0~1.6倍和1.0~1.2倍,DOB值和DS值分别是长期老化废旧沥青的1.4~1.8倍和1.7~1.9倍,并且前者可实现100%完全融合状态,后者融合程度仅能达到70%。而随作用时间增加,V值和DS值呈指数函数快速下降,Wb值和DOB值呈对数函数快速增加,各行为参数最终均趋于稳定。再生剂-废旧沥青界面铺展润湿行为和扩散融合特征线性相关性显著,通过测试前一阶段界面铺展润湿行为效应可精准预估后一阶段扩散融合性能结果,为科学评价RAP沥青界面扩散融合特征提供了新途径。 展开更多
关键词 废旧沥青路面材料 界面铺展润湿 界面扩散融合 界面接触角 相关性方程
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Pseudorapidity dependence of short-range correlations from a multi-phase transport model
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作者 王美娟 陈刚 +1 位作者 马国亮 吴元芳 《Chinese Physics C》 SCIE CAS CSCD 2016年第3期85-89,共5页
Using a multi-phase transport model(AMPT) that includes both initial partonic and hadronic interactions, we study neighboring bin multiplicity correlations as a function of pseudorapidity in Au+Au collisions at √s... Using a multi-phase transport model(AMPT) that includes both initial partonic and hadronic interactions, we study neighboring bin multiplicity correlations as a function of pseudorapidity in Au+Au collisions at √sNN= 7.7- 62.4 GeV.It is observed that for √sNN〈19.6 GeV Au+Au collisions, the short-range correlations of final particles have a trough at central pseudorapidity, while for √sNN 〉19.6 GeV AuAu collisions,the short-range correlations of final particles have a peak at central pseudorapidity. Our findings indicate that the pseudorapidity dependence of short-range correlations should contain some new physical information, and are not a simple result of the pseudorapidity distribution of final particles. The AMPT results with and without hadronic scattering are compared. It is found that hadron scattering can only increase the short-range correlations to some level, but is not responsible for the different correlation shapes for different energies. Further study shows that the different pseudorapidity dependence of short-range correlations are mainly due to partonic evolution and the following hadronization scheme. 展开更多
关键词 short-range correlations hadronic interaction partonic evolution hadronization scheme
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