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Genome-wide Characterization of cis-acting Elements in the Promoters of Key Carotenoid Pathway Genes from the Main Species of Genus Citrus 被引量:13
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作者 Kaijie Zhu Qingjiang Wu +3 位作者 Yue Huang Junli Ye Qiang Xu Xiuxin Deng 《Horticultural Plant Journal》 SCIE 2020年第6期385-395,共11页
Carotenoids are indispensable for both human health and plant survival.Citrus,is one of the fruit crops richest in carotenoid compounds,with approximately 115 kinds of carotenoids;tremendous diversity in carotenoids c... Carotenoids are indispensable for both human health and plant survival.Citrus,is one of the fruit crops richest in carotenoid compounds,with approximately 115 kinds of carotenoids;tremendous diversity in carotenoids composition and concentration exists among various species,showing different colors from nearly white to crimson.The carotenoid biosynthetic pathway and the key carotenogenic genes have been identified in citrus;however,the underlying regulatory mechanisms remain unclear.In this study,among the main species of genus Citrus(primitive,wild,and cultivated),we detected carotenoids in flavedo using High-Performance Liquid Chromatography,and analyzed variations in cis-acting elements in the promoters of key carotenoid pathway genes.Intriguingly,both carotenoid composition and content were generally increased during the evolution of citrus,and the corresponding variations in the promoters were identified,including the gain or loss of critical environmental stress-responsive elements and hormone-responsive elements,which are closely associated with carotenoid enhancement.In addition,pummelo has the most heat-responsive elements,but the Mangshan mandarin does not have this element in the promoters of PSY,which is highly related to their geographical origin and indicate that temperature is a critical environmental signal influencing carotenoid accumulation.Moreover,the abscisic acid-responsive motif was rich in almost all the seven species,but the ethylene-responsive motif was deficient,which demystified the unique phytohormone regulation mechanism of carotenoid accumulation in citrus.Overall,our study provides new insights into the molecular regulatory mechanism of carotenoid enhancement in the evolution of citrus,which can facilitate breeding and cultivation efforts to improve the nutritional quality and esthetic value in citrus and hopefully other fruit crops. 展开更多
关键词 CITRUS CAROTENOID PROMOTER Evolution cis-acting element
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Genomic Analysis of MicroRNA Promoters and Their Cis-Acting Elements in Soybean 被引量:5
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作者 LIU Yong-xin HAN Ying-peng +3 位作者 CHANG Wei ZOU Quan GUO Mao-zu LI Wen-bin 《Agricultural Sciences in China》 CSCD 2010年第11期1561-1570,共10页
MicroRNAs (miRNAs) are derived from distinct loci in the genome and play crucial roles in RNA-mediated gene silencing mechanisms that regulate cellular processes during development and stress responses of plants. Th... MicroRNAs (miRNAs) are derived from distinct loci in the genome and play crucial roles in RNA-mediated gene silencing mechanisms that regulate cellular processes during development and stress responses of plants. The miRNAs are approximately 21 nucleotides long and code for the complementary strand to a larger genic mRNA. They are often found within the complementary primary transcript (pri-miRNAs). In the past few years, a growing number of soybean miRNAs have been discovered, however, little is known about the transcriptional regulation of these miRNAs. In this study, promoters and cis-acting elements of soybean miRNAs were analyzed using the genomic data for the first time. A total of 82 miRNAs were located among 122 loci in genome, some were present as double or multiple copies. Five clusters that included ten miRNAs were found in genome, and only one cluster share the same promoter. A total of 191 promoters from 122 loci of the soybean miRNA sequences were found and further analyzed. The results indicated that the conserved soybean miRNA genes had a greater proportion of promoters than that of non-conserved ones, and the distribution of the transcript start sites (TSSs) and TATA-boxes found had different motif styles between conserved and non-conserved miRNA genes. Furthermore, the cis-acting elements 5' of the TSSs were analyzed to obtain potential function and spatiotemporal expression pattern of miRNAs. The data obtained here may lead to the identification of specific sequences upstream of pre-miRNAs and the functional annotation of miRNAs in soybean. 展开更多
关键词 MIRNAS SOYBEAN PROMOTER cis-acting elements miRNA clusters
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Three-dimensional finite element analysis of critical pre-twist strain angle for torsional axis
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作者 周国锋 李晓延 +1 位作者 史耀武 徐滨士 《Journal of Central South University》 SCIE EI CAS 2005年第S2期254-256,共3页
A three-dimensional elasto-plastic finite element analysis of pre-twist process for a torsional axis made of 45GrNiMoVA steel, was carried out using a commercial finite element analysis code, MSC MARC 2001. The result... A three-dimensional elasto-plastic finite element analysis of pre-twist process for a torsional axis made of 45GrNiMoVA steel, was carried out using a commercial finite element analysis code, MSC MARC 2001. The results show that the critical pre-twist strain angle is 0.027 rad and the maximum elastic shear stress after pre-twist is 1694MPa for the torsional axis. 展开更多
关键词 torsional AXIS critical STRAIN ANGLE FINITE element analysis
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Distribution of Selected Critical Elements in the Carboniferous Coal-bearing Series of the Upper Silesian and Lublin Coal Basins(Poland)
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作者 Ewa KRZESZOWSKA Magdalena KOKOWSKA-PAWLOWSKA Swiatoslaw KRZESZOWSKI 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2022年第1期273-292,共20页
The distribution of selected critical elements in the sedimentary rocks of the Carboniferous coal-bearing series within the Polish Coal Basins is presented.Critical elements such as Be,Mg,Si,P,Sc,V,Co,Y,Nb,In,Sb,La,Ce... The distribution of selected critical elements in the sedimentary rocks of the Carboniferous coal-bearing series within the Polish Coal Basins is presented.Critical elements such as Be,Mg,Si,P,Sc,V,Co,Y,Nb,In,Sb,La,Ce,Hf,Ta,W,Bi were analysed using inductively-coupled plasma mass spectrometry(ICP/MS).Concentrations of elements such as Sb,Bi,In and,to a slightly lesser extent,Nb,as well as Sc,show average concentrations higher than those from the upper continental crust.The average concentrations of elements like Hf,Mg,P,Y,La,and Ce are slightly lower than in the upper continental crust.Other elements,such as Be,Co,Si,Ta,W and V have average concentrations that are similar,but slightly enriched or slightly depleted,relative to the upper continental crust.The research showed enrichment of some critical elements in the analysed samples,but not high enough that extraction would be economically viable.Statistical methods,which include correlation coefficients between elements and cluster analysis,reveal a strong positive correlation between elements like Be,Bi,Nb,Sc,Ta,W and V.Very high,almost total,positive correlation is also noted between La and Ce. 展开更多
关键词 geochemistry critical elements coal-bearing series Upper Silesian Coal Basin Lublin Coal Basin
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Comparing mineral weathering and elemental transport between earth's critical zone with different parent rocks in Yanshan Mountain,Hebei province,China
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作者 Zijian Sun Zhen Liao +7 位作者 Wei Shen Daqing Fu Xiaofeng Wei Huiqiong Zhang Ziran Chen Lianghui Xiong Tianhao An Hao Wei 《Acta Geochimica》 EI CAS CSCD 2022年第6期982-999,共18页
Bedrock weathering performs a significant influence on the evolution of Earth’s critical zone.Carbonate rock(dolostone),metamorphic rock(gneiss),and sedimentary rock(sandstone)geological formations in Yanshan Mountai... Bedrock weathering performs a significant influence on the evolution of Earth’s critical zone.Carbonate rock(dolostone),metamorphic rock(gneiss),and sedimentary rock(sandstone)geological formations in Yanshan Mountain,Hebei Province,are taken as objects to probe the controlling of geological formations on weathering characteristics,migration,and enrichment of elements as well as structure of Earth’s critical zone under the identical climate conditions through geological field survey,analysis on minerals component,element distribution in the weathering profile.The dolostone geological formation(DGF)is lithologically dominated by dolostone,characterized by the strongest and predominant chemical weathering.During bedrock weathering and pedogenesis,DGF is marked by significant depletion of CaO,Mg O,S,Mn,Mo and enrichment of N,K,Fe_(2)O_(3),and Zn with concentrations of P,Cu,and B keeping stable.Shortage of soil-forming materials and significant loss are driven by soil erosion,which results in thin regolith and soil.The soil thickness is less than 10 cm,and the regolith thickness is less than 30 cm.The vegetation community is predominantly rock arbor or brush,which is calcivorous and tolerant of barrenness.Plagiogneiss is a dominant rock type of gneiss geological formation(GGF),characterized by the weakest weathering and fast chemical and physical weathering rate.GGF is masked by significant depletion of P,K,CaO,MgO,Fe_(2)O_(3),Mn,Cu and enrichment of N,S,Mo,and B,with contents of Zn keeping stable.Both soil and regolith developed in GGF are relatively thick for one of the reasons that biotite expands during weathering.The soil thickness is more than 50 cm,and the regolith thickness ranges from 100 to 200 cm.The vegetation community is predominantly high-quality economic forests and various arbors because of the enrichment of nutrients in GGF.Sandstone is primarily a rock type of sandstone geological formation(SGF),characterized by moderate weathering degree and slow chemical weathering rate.SGF is marked by significant depletion of P,K,CaO,MgO,Fe_(2)O_(3),and enrichment of N,S,Mn,Cu,Zn,and Mo,with fluctuant changes of Zn and B.The thickness of soil developed in SGF varies between that of DGF and GGF.The soil thickness ranges from 30 to 50 cm,and the regolith thickness ranges from 50 to 100 cm.Chinese pines are widely spread on the shady slopes of SGF.Research provides theoretical support for screening dominant ecological resource areas,ecological industry development and ecological protection and restoration for Yanshan Mountain,Hebei Province. 展开更多
关键词 Yanshan Mountain Earth’s critical zone Rock weathering PEDOGENESIS Migration and enrichment of element
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基于AHP-CRITIC综合权重的改进物元可拓模型在地下水水质评价中的应用
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作者 刘刚 徐斌 +3 位作者 陈璐璐 黄星 陈子方 张文俊 《中国环境监测》 CAS CSCD 北大核心 2024年第3期125-133,共9页
权重的确定在地下水水质评价中具有重要作用。利用CRITIC方法对地下水指标进行权重修正,探究该方法对地下水质量评价的适用性。笔者选取代表性指标后,按照一般化学指标、毒理学指标2个层次构建地下水污染评价综合指标体系,建立基于AHP-C... 权重的确定在地下水水质评价中具有重要作用。利用CRITIC方法对地下水指标进行权重修正,探究该方法对地下水质量评价的适用性。笔者选取代表性指标后,按照一般化学指标、毒理学指标2个层次构建地下水污染评价综合指标体系,建立基于AHP-CRITIC综合权重的改进物元可拓模型对研究区地下水开展质量评价。将开发的评价方法应用于工业园区地下水质量评价发现,该方法能够反映地下水质量状况。结果表明:该评价方法在地下水质量评价过程中,能够兼顾不同指标重要程度差异和水质等级的模糊性,研究区5#点位和10#点位有毒有害重金属超标,应进一步查明原因,提出地下水污染阻断措施。 展开更多
关键词 层次分析法 critic 物元可拓模型 地下水质量评价
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Critical load position for cavities beneath CRCP slab under vehicle loading 被引量:2
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作者 陈小兵 赵蓉龙 +2 位作者 童金虎 黄晓明 罗瑞林 《Journal of Southeast University(English Edition)》 EI CAS 2016年第1期78-84,共7页
In order to study the critical load position that causes cavities beneath the continuously reinforced concrete pavement( CRCP) slab under vehicle loading, the elliptical load is translated into the square load based... In order to study the critical load position that causes cavities beneath the continuously reinforced concrete pavement( CRCP) slab under vehicle loading, the elliptical load is translated into the square load based on the equivalence principle.The CRCP slab is analyzed to determine the cavity position beneath the slab under vehicle loading. The influences of cavity size on the CRCP slab's stress and vertical displacement are investigated. The study results showthat the formation of the cavity is unavoidable under traffic loading, and the cavity is located at the edge of the longitudinal crack and the slab corner.The cavity size exerts an obvious influence on the largest horizontal tensile stress and vertical displacement. The slab corner is the critical load position of the CRCP slab. The results can be used to assist the design of CRCP in avoiding cavities beneath slabs subject to vehicle loading. 展开更多
关键词 vehicle loading CAVITY continuously reinforced concrete pavement(CRCP) critical load position finite element method(FEM)
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Effects of temperature and strain rate on critical damage value of AZ80 magnesium alloy 被引量:4
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作者 夏玉峰 权国政 周杰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第B07期580-583,共4页
A series of AZ80 billets were compressed with 60%height reduction on hot process simulator at 250,300,350,400℃ under strain rates of 0.01,0.1,1 and 10 s- 1.In order to predict the occurrence of surface fracture,the v... A series of AZ80 billets were compressed with 60%height reduction on hot process simulator at 250,300,350,400℃ under strain rates of 0.01,0.1,1 and 10 s- 1.In order to predict the occurrence of surface fracture,the values of the Cockcroft-Latham equation were calculated by the corresponding finite element numerical algorithm developed.A concept about damage incremental ratio in plastic deformation was defined as the ratio of damage increment at one step to the accumulated value.A method of finding the intersection of incremental ratio varying curve and simulation step axis was brought forward to make the fracture step certain. Then,the effects of temperature and strain rate on critical damage value were achieved.The results show that the critical damage value is not a constant but changes in a range of 0.021 8-0.378 0.It decreases significantly with the increase of strain rate at a certain temperature.While under a certain strain rate,the critical damage value has little change with the increase of temperature. 展开更多
关键词 AZ80 magnesium alloy critical damage value COMPACTION finite element analysis
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Critical Top Tension for Static Equilibrium Configuration of A Steel Catenary Riser 被引量:3
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作者 Chainarong ATHISAKUL Karun KLAYCHAM Somchai CHUCHEEPSAKUL 《China Ocean Engineering》 SCIE EI CSCD 2014年第6期829-842,共14页
This paper aims to present the critical top tension for static equilibrium configurations of a steel catenary riser(SCR) by using the finite element method. The critical top tension is the minimum top tension that c... This paper aims to present the critical top tension for static equilibrium configurations of a steel catenary riser(SCR) by using the finite element method. The critical top tension is the minimum top tension that can maintain the equilibrium of the SCR. If the top tension is smaller than the critical value, the equilibrium of the SCR does not exist. If the top tension is larger than the critical value, there are two possible equilibrium configurations. These two configurations exhibit the nonlinear large displacement. The configuration with the smaller displacement is stable, while the one with larger displacement is unstable. The numerical results show that the increases in the riser's vertical distances, horizontal offsets, riser's weights, internal flow velocities, and current velocities increase the critical top tensions of the SCR. In addition, the parametric studies are also performed in order to investigate the limit states for the analysis and design of the SCR. 展开更多
关键词 critical top tension finite element method large displacement steel catenary riser static equilibrium
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On a New Equation for Critical Current Density Directly in Terms of the BCS Interaction Parameter, Debye Temperature and the Fermi Energy of the Superconductor 被引量:2
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作者 G. P. Malik 《World Journal of Condensed Matter Physics》 2013年第2期103-110,共8页
Recasting the BCS theory in the larger framework of the Bethe-Salpeter equation, a new equation is derived for the temperature-dependent critical current density jc(T) of an elemental superconductor (SC) directly in t... Recasting the BCS theory in the larger framework of the Bethe-Salpeter equation, a new equation is derived for the temperature-dependent critical current density jc(T) of an elemental superconductor (SC) directly in terms of the basic parameters of the theory, namely the dimensionless coupling constant [N(0)V], the Debye temperature θD and, additionally, the Fermi energy EF—unlike earlier such equations based on diverse, indirect criteria. Our approach provides an ab initio theoretical justification for one of the latter, text book equations invoked at T = 0 which involves Fermi momentum;additionally, it relates jc with the relevant parameters of the problem at T ≠ 0. Noting that the numerical value of EF of a high-Tc SC is a necessary input for the construction of its Fermi surface—which sheds light on its gap-structure, we also briefly discuss extension of our approach for such SCs. 展开更多
关键词 critical Current Density BCS Parameters FERMI Energy elemental/Non-elemental SUPERCONDUCTORS
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Geochemical characteristics and growth suitability assessment of Scutellaria baicalensis Georgi in the Earth's critical zone of North China 被引量:1
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作者 LI Xia WEI Xiao-feng +4 位作者 WU Jin YIN Zhi-qiang WAN Li-qin SUN Hou-yun AN Yong-long 《Journal of Mountain Science》 SCIE CSCD 2022年第5期1245-1262,共18页
Geochemical differentiation of soils has a series of consequences on plant and places pressure on the ecological environment.The quantitative evaluation of element migration in the Earth’s critical zone is a challeng... Geochemical differentiation of soils has a series of consequences on plant and places pressure on the ecological environment.The quantitative evaluation of element migration in the Earth’s critical zone is a challenging task.In this study,two demonstration study areas of Scutellaria baicalensis Georgi were selected,and multiple chemical weathering indexes,chemical loss fraction,mass migration coefficients and biological enrichment coefficient method were used to assess the ecological and geochemical suitability.The results show that for the element of Fe,Zn,Se,Cu,Co,Ni,Mo and Ge,the degree of weathering and soil maturation,were greater in the rhyolitic tuff area than in the Plagioclase gneiss area.In both research sites,the heavy metal level of samples in Scutellaria baicalensis Georgi did not exceed the standard limits.The plagioclase gneiss region’s surface soil environment was more alkaline,and the content of soil organic matter was lower,resulting in a higher bioenrichment intensity of Ge,Co,Cu,and Se elements in Scutellaria baicalensis Georgi than in the rhyolite-tuff area.The elements of Cd,Nb,Mo,Pb and As are considerably enriched in the soil of the plagioclase gneiss area but lost by leaching in the soil of the rhyolite tuff area,which is connected to the interplay of elemental abundance and human impact in the parent materials.This study provides a good example of how to assess growth suitability of Chinese medicinal materials in the Earth’s critical zone. 展开更多
关键词 Earth’s critical zone Biogeochemistry characteristics Weathering mechanism element migration Chinese medicinal materials Chengde
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Critical velocity and dynamic respondency of pipe conveying fluid
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作者 王世忠 于石声 王东海 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2001年第1期87-89,共3页
Presents the calculation of critical velocity, natural frequency and dynamic respondency of fluid conveying pipe are calculated under different boundary conditions using finite element method, and the use of calculati... Presents the calculation of critical velocity, natural frequency and dynamic respondency of fluid conveying pipe are calculated under different boundary conditions using finite element method, and the use of calculation results to design and research rocket pipes feeding fuel and watery turbine pipes conveying water etc. 展开更多
关键词 PIPE finite element method critical velocity natural frequency dynamic respondency
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火电厂燃煤产物中关键微量元素富集特征研究 被引量:1
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作者 朱士飞 毛礼鑫 +1 位作者 张静 曹磊 《中国煤炭地质》 2024年第3期21-26,共6页
煤系共伴生战略性关键元素可在燃煤产物中富集,研究燃煤产物中关键元素的富集特点可为元素的预富集和提取利用提供依据。以我国东西部不同火电厂燃煤产物为例,采用波长色散荧光光谱仪(AxiosmAX)、电感耦合等离子体质谱仪(iCAP-Qc)测试... 煤系共伴生战略性关键元素可在燃煤产物中富集,研究燃煤产物中关键元素的富集特点可为元素的预富集和提取利用提供依据。以我国东西部不同火电厂燃煤产物为例,采用波长色散荧光光谱仪(AxiosmAX)、电感耦合等离子体质谱仪(iCAP-Qc)测试了燃煤产物中常量元素和关键微量元素的含量,分析了燃煤产物中关键微量元素分布富集的一般性规律。结果表明:①粉煤灰中主要常量元素为Si、Al、Fe,三者氧化物占比达87.79%;微量元素中稀土元素、锂、镓、铀、锗的含量分别为456.95μg/g、163.58μg/g、49.07μg/g、8.67μg/g、4.59μg/g,除铀、锗外均高于世界煤灰平均值。②常量元素中P趋向富集于细灰中,Fe、Ca更易富集于粗灰中;稀土元素分布模式保持一致,且在细灰中的含量高于粗灰,锂、镓、铀、锗均在细粒燃煤产物中更为富集,分异系数分别为1.17、2.45、1.53、2.14。③数理统计分析表明,煤中稀土元素与无机矿物相关,且富集于燃煤产物的非磁性组分中;锂主要与黏土矿物有关,燃烧后主要以LiAlO2的形式存在;镓、铀赋存形式不单一,与黏土矿物有一定的关系;锗与无机相相关性弱,表明其主要与有机质结合。 展开更多
关键词 燃煤产物 稀土元素 关键元素富集
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中国舞蹈艺术的审美文化观——内外部相融的舞蹈研究方法论探讨 被引量:1
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作者 慕羽 《南京艺术学院学报(音乐与表演版)》 北大核心 2024年第1期146-161,I0005,共17页
舞蹈创作和批评研究既包括“生命体”身体意识和时空关系的内部规律探讨,也要阐释舞蹈与人类其他社会实践的外部规律联系,内外部结合的方法论很有意义。舞蹈分析与动作分析并非相同概念。舞蹈创作和研究从业者除了提升动作分析理论,还... 舞蹈创作和批评研究既包括“生命体”身体意识和时空关系的内部规律探讨,也要阐释舞蹈与人类其他社会实践的外部规律联系,内外部结合的方法论很有意义。舞蹈分析与动作分析并非相同概念。舞蹈创作和研究从业者除了提升动作分析理论,还应密切关注新的编舞走向和跨学科的舞蹈研究趋势。20世纪八九十年代以来,西方舞蹈学者的舞蹈分析框架,融入了文化研究,揭示出仅作动作分析或内部研究的局限性;中国舞蹈学者的元素分析、形态分析也与舞蹈文化密切相关。在全球在地化和全媒体时代,作为一种方法论,舞蹈艺术的“审美文化观”将舞蹈创作到批评视为审美文化活动,承袭了古今中西文化汇通的中国美学、文学、理论界和舞蹈学的相关研究,自律论、他律论与通律论相辅相成,重视具体的真实的人本体,一方面强调侧重内部研究的“跨媒介性”视角,另一方面也倡导将内外部打通的“跨文化”观,尝试既在审美中看舞蹈文化,也在文化中看舞蹈审美,是一种具有“中国式现代化”路径的文艺观和方法论。“点线面体”充分融合的审美文化四面体图式,基于艾布拉姆斯“四要素”三角和格里斯沃尔德“文化菱形”理论基础,融入拉班动作分析四面体思路,并与中国人文社科学术界倡导多年的“审美文化”研究相通。 展开更多
关键词 中国舞蹈创作 中国舞蹈批评 方法论 审美文化 四要素 四面体
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基于AHP-CRITIC-云物元法的市政园林项目 绩效评价模型
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作者 彭志远 白叶然 《中国市政工程》 2023年第3期106-109,122,共5页
为科学合理评价市政园林建设项目绩效水平,构建了经济、社会、环境、管理4个维度共19项指标的评价指标体系,采用AHP法确定指标主观权重、CRITIC法确定指标客观权重,并运用最小鉴别信息原理与拉格朗日乘子确定指标组合权重。基于云物元... 为科学合理评价市政园林建设项目绩效水平,构建了经济、社会、环境、管理4个维度共19项指标的评价指标体系,采用AHP法确定指标主观权重、CRITIC法确定指标客观权重,并运用最小鉴别信息原理与拉格朗日乘子确定指标组合权重。基于云物元法构建评价模型,并将模型应用到天津轨道交通L4某车辆段周边市政园林配套工程进行评价验证,得出项目绩效水平为二级,属于“良好”状态。结果表明采用AHP-CRITIC-云物元模型评价市政园林建设项目是科学可行的,能够较好地反映实际项目绩效水平状况。 展开更多
关键词 层次分析法 critic 云物元 市政园林 绩效评价
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深厚软土区桩柱式桥墩临界荷载简化计算方法
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作者 刘晓明 李曦 +3 位作者 刘齐建 刘涛 殷悦 曾磊 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第3期92-98,共7页
现有桩柱式桥墩临界荷载简化计算方法在大多数情况下计算误差较大,适用性有限.在利用软土区现场桩基屈曲实验结果标定的基础上,采用基于特征值屈曲分析的有限元方法对有典型桩柱式桥墩的临界荷载进行了计算并与现有简化计算方法结果进... 现有桩柱式桥墩临界荷载简化计算方法在大多数情况下计算误差较大,适用性有限.在利用软土区现场桩基屈曲实验结果标定的基础上,采用基于特征值屈曲分析的有限元方法对有典型桩柱式桥墩的临界荷载进行了计算并与现有简化计算方法结果进行了对比,指出了现有简化计算方法的适用范围,发现现有简化方法不适用于软土区桩柱式桥墩计算.在大量桩柱式桥墩有限元特征值屈曲分析数据的基础上,采用随机森林算法对计算结果进行分析,得到可以计算桩柱式桥墩计算长度的随机森林模型以及各影响参数重要性指数分析结果.最后以现常用简化公式为基本形式,纳入随机森林算法给出的重要参数,通过回归分析,提出了深厚软土区桩柱式桥墩临界荷载的简化计算方法. 展开更多
关键词 桩柱式桥墩 临界荷载 有限元 随机森林
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更高速下轮轨瞬态“滚-滑-跳”接触行为及中/短波不平顺临界限值研究
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作者 赵鑫 黄双超 +2 位作者 杨吉忠 Zhen YANG 温泽峰 《铁道学报》 EI CAS CSCD 北大核心 2024年第10期21-32,共12页
简述轮轨滚动接触行为预测方法现状的基础上,选择最适于400 km/h及以上更高速和中/短波不平顺激励下轮轨“滚-滑-跳”接触行为分析的瞬态滚动接触显式有限元建模方法,建立更高速轮轨三维瞬态滚动接触时域分析模型,数值模拟了轮对在典型... 简述轮轨滚动接触行为预测方法现状的基础上,选择最适于400 km/h及以上更高速和中/短波不平顺激励下轮轨“滚-滑-跳”接触行为分析的瞬态滚动接触显式有限元建模方法,建立更高速轮轨三维瞬态滚动接触时域分析模型,数值模拟了轮对在典型曲线轨道上的瞬态曲线通过行为。根据现营高速轮轨的中/短波不平顺调研,以波长30~210 mm钢轨波磨为典型不平顺,考虑波磨激励下左右两侧轮轨动力作用相互影响,分析波磨几何等因素对速度500 km/h及以下轮轨瞬态“滚-滑-跳”接触行为的影响。考虑低、中频动力减载等因素的前提下,仅从轮轨接触脱离角度,提出轮轨中/短波不平顺的临界管理限值建议,讨论其重要性、合理性和应用局限,并与《高速铁路钢轨打磨管理办法》规定的波磨整治限度进行对比。 展开更多
关键词 更高速铁路 轮轨滚动接触 中/短波不平顺 轮轨脱离 临界限值 显式有限元
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大学英语教学中人文素养教育的关键要素和实现理路
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作者 吴天慧 《武汉工程职业技术学院学报》 2024年第3期71-76,共6页
通过深入分析环境、教师和课程等关键要素,从宏观统筹、中观着力和微观实践三个维度,探求数字化视野下加强大学英语教学中人文素养教育的实现理路。
关键词 大学英语 人文素养教育 关键要素 实现理路
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呼吸与危重症学课程思政设计与实施策略
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作者 康小文 李璐 +2 位作者 陈美 迟雨欣 孔亚娟 《中国继续医学教育》 2024年第8期171-174,共4页
医学教育在高等教育领域里占有重要的地位,肩负着培养医学人才,维护和促进人民健康的重要使命。这一使命在公共卫生事件救治过程中得到很好的诠释,涌现出一批舍小家顾大家、不顾及个人利益、勇挑重担、无私奉献、生命至上的光辉事迹。... 医学教育在高等教育领域里占有重要的地位,肩负着培养医学人才,维护和促进人民健康的重要使命。这一使命在公共卫生事件救治过程中得到很好的诠释,涌现出一批舍小家顾大家、不顾及个人利益、勇挑重担、无私奉献、生命至上的光辉事迹。如何将这些精神持续的传承值得思考。习近平总书记强调把思想政治工作贯穿教育教学全过程。用科学理论培养人,重视思政课的实践性。明确与挖掘每门课程都内在的思政元素,是推进课程思政的认识基础。呼吸与危重症学是临床医学中重要组成部分之一,呼吸道疾病也是我国的常见病与高发病之一,也是医学生踏入临床的必修课之一。为此,笔者根据课程特点探索呼吸与危重症学思政元素以及思政与专业知识融入方式,全面认识和把握课程中的思政元素,以促进学生全面发展。 展开更多
关键词 医学教育 课程思政 呼吸与危重症学 思政元素 高等教学 医学生
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稀土元素的生物毒害性研究进展 被引量:1
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作者 王园园 傅浩洋 +2 位作者 朱建喜 何宏平 梁晓亮 《地球化学》 CAS CSCD 北大核心 2024年第1期3-16,共14页
稀土由于具有独特的物理化学性质,被广泛地应用于电子、冶金、机械、石油化工等多个领域。随着其应用范围的不断扩大,稀土元素不可避免地进入环境,并可能通过食物链、呼吸、皮肤接触等多种途径对人类健康产生威胁。因此,研究稀土元素的... 稀土由于具有独特的物理化学性质,被广泛地应用于电子、冶金、机械、石油化工等多个领域。随着其应用范围的不断扩大,稀土元素不可避免地进入环境,并可能通过食物链、呼吸、皮肤接触等多种途径对人类健康产生威胁。因此,研究稀土元素的生物毒害性有利于增强对稀土元素的全面认识,对评估稀土环境风险具有重要意义。本文综述了近年来稀土元素的生物毒害性研究进展,主要包括:稀土元素对植物、动物和人体的生物毒害效应及其机制;稀土元素的不同暴露方式及其健康影响;稀土元素的安全临界剂量研究进展。当前由于人们对稀土元素的生物毒害效应认识不足,因此,未来应加强对稀土不同暴露方式下的人体健康效应的关注。尤其需要注意在离子吸附型稀土矿大面积出露的华南地区,自然区的暴露作用不容忽视,特别要警惕人群的摄食量和与稀土元素可能有关的病症;基于现有对稀土暴露方式的认识,优化作业流程并加强管理,减少甚至切断相关稀土暴露源;加快建立并推行稀土安全临界剂量标准,为稀土污染评价和环境治理提供参考。 展开更多
关键词 稀土元素 生物毒害性 暴露作用 安全临界剂量
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