期刊文献+
共找到249篇文章
< 1 2 13 >
每页显示 20 50 100
基于多重变换组合的动态地图符号设计 被引量:12
1
作者 祝国瑞 徐智勇 吴小芳 《武汉大学学报(信息科学版)》 EI CSCD 北大核心 2006年第6期548-551,共4页
采用面向对象的设计方法,将符号的状态描述(参量)与过程操作(对不同参量实施不同变换)封装,采用关键帧-层-图元-几何/非几何属性结构进行符号组织,从而将地图符号的时间维信息纳入到符号设计之中,建立了不同的变化速率模型,实现属性的... 采用面向对象的设计方法,将符号的状态描述(参量)与过程操作(对不同参量实施不同变换)封装,采用关键帧-层-图元-几何/非几何属性结构进行符号组织,从而将地图符号的时间维信息纳入到符号设计之中,建立了不同的变化速率模型,实现属性的动态变化;通过图元与图元之间的二维Morph函数变换矩阵,结合仿射变换,对符号的几何信息进行快速提取,从而实现了符号的动态显示。 展开更多
关键词 动态符号 符号设计 morph 可视化
下载PDF
Comparison of the potential rate of population increase of brown and green color morphs of Sitobion avenae (Homoptera: Aphididae) on barley infected and uninfected with Barley yellow dwarf virus 被引量:6
2
作者 Zu-Qing Hu Hui-Yan Zhao Thomas Thieme 《Insect Science》 SCIE CAS CSCD 2014年第3期326-333,共8页
Life tables of brown and green color morphs of the English grain aphid, Sitobion avenae (Fabricius) reared on barley under laboratory conditions at 20 + 1℃,65% ± 5% relative humidity and a photoperiod of 16 ... Life tables of brown and green color morphs of the English grain aphid, Sitobion avenae (Fabricius) reared on barley under laboratory conditions at 20 + 1℃,65% ± 5% relative humidity and a photoperiod of 16 : 8 h (L : D) were compared. The plants were either: (i) infected with the Barley yellow dwarf virus (BYDV); (ii) not infectedwith virus but previously infested with aphids; or (iii) healthy barley plants, which were not previously infested with aphids. Generally, both color morphs of S. avenae performedsignificantly better when fed on BYDV-infected plants than on plants that were virus free but had either not been or had been previously infested with aphids. Furthermore,when fed on BYDV-infected plants, green S. avenae developed significantly faster and had a significantly shorter reproductive period than the brown color morph. There wereno significant differences in this respect between the two color morphs ofS. avenae when they were reared on virus-free plants that either had been or not been previously infestedwith aphids. These results indicate that barley infected with BYDV is a more favorable host plant than uninfected barley for both the color morphs ofS. avenae tested, particularly the green color morph. 展开更多
关键词 Barley yellow dwarf virus color morph life table Sitobion avenae
原文传递
异尾华枝虫生物学特性及防治 被引量:8
3
作者 包其敏 金觉远 +3 位作者 包文斌 蔡胡敏 何潘淼 林青兰 《森林病虫通讯》 北大核心 2000年第3期15-17,共3页
异尾华枝 虫 Sinophasma mirabile Günther在华东地区是一种新发现的危害壳斗科树木的重要食叶害虫。在浙江泰顺 1年发生 1代 ,以卵越冬 ,若虫和成虫大量取食寄主树叶造成树木生长衰弱甚至枯死。该文介绍了该虫的年生活史、发育... 异尾华枝 虫 Sinophasma mirabile Günther在华东地区是一种新发现的危害壳斗科树木的重要食叶害虫。在浙江泰顺 1年发生 1代 ,以卵越冬 ,若虫和成虫大量取食寄主树叶造成树木生长衰弱甚至枯死。该文介绍了该虫的年生活史、发育过程、生活习性、取食量、天敌种类和防治方法 ,采用燃放烟剂、树干注药、地面喷药等措施 。 展开更多
关键词 异尾华枝Xiu 生物学特性 防治 森林害虫 壳斗科
下载PDF
某轿车车身正面碰撞安全性能优化 被引量:4
4
作者 乔鑫 邢如飞 +1 位作者 孔繁华 杨越凯 《沈阳理工大学学报》 CAS 2012年第2期54-57,61,共5页
针对"汽车车身安全性能指标改进"的项目要求,利用有限元碰撞仿真技术,通过田口方法(DOE)和自动型面优化方法(morph)分析正面碰撞中车身结构存在的问题,完成结构优化,达到改进车身安全性能的目的。通过此方法可为解决车身的碰... 针对"汽车车身安全性能指标改进"的项目要求,利用有限元碰撞仿真技术,通过田口方法(DOE)和自动型面优化方法(morph)分析正面碰撞中车身结构存在的问题,完成结构优化,达到改进车身安全性能的目的。通过此方法可为解决车身的碰撞安全性能提供参考,提高工作效率。 展开更多
关键词 正面碰撞 结构优化 DOE morph
下载PDF
Morphological plasticity and adaptation level of distylous Primula nivalis in a heterogeneous alpine environment 被引量:5
5
作者 Aysajan Abdusalam Qingjun Li 《Plant Diversity》 SCIE CAS CSCD 2018年第6期284-291,共8页
Plant populations at high elevation face extreme climatic conditions and resource limitations. The existence of distylous species at different elevations can help us investigate their adaptation to high altitudes, the... Plant populations at high elevation face extreme climatic conditions and resource limitations. The existence of distylous species at different elevations can help us investigate their adaptation to high altitudes, the evolution of their morphological characteristics, as well as their responses to limited resources. Here, 17 populations of Primula nivalis at different elevations were evaluated regarding variations in plant morphological characteristics, biomass allocation, and morphological plasticity in a heterogeneous environment. Our results demonstrate that heterogeneous environments can affect plant morphological characteristics and resource allocation in each sexual morph of these plants. Moreover,environmental variations reduced morphological plasticity in the two plant morphs, and the plasticity of long style(LS) plants was greater than that of short style(SS) plants. There were significant negative correlations between morphological characteristics and elevation, rainfall, temperature, and sunshine,and these are the main variables that affect morphological characteristics and resource allocation of both morphs of P. nivalis plants in heterogeneous environments. The morphological characteristics of P. nivalis plants transplanted from high to lower elevations were not significantly different in either population.LS plants had greater morphological plasticity and adaptability in heterogeneous environments than SS plants. Elevational gradients and heterogeneous environments differentiated both morphs of P. nivalis plants with regards to morphology as well as adaptations. LS plants showed a higher level of adaptability than SS plants. 展开更多
关键词 Biomass ALLOCATION Plant sexual morph morphOLOGICAL characteristics Adaptation
下载PDF
基于多参数优化的某后扭力梁设计 被引量:2
6
作者 杨发富 赵云 《中国汽车》 2022年第3期48-54,共7页
首先构建了某后扭力梁有限元模型,并对其进行强度、扭转刚度、模态分析,结果表明,初始结构的后扭力梁U字形截面横梁有一个强度工况不达标,扭转刚度及弯曲模态均不满足目标要求。然后以5个料厚参数为设计变量,以扭转刚度及模态为响应,进... 首先构建了某后扭力梁有限元模型,并对其进行强度、扭转刚度、模态分析,结果表明,初始结构的后扭力梁U字形截面横梁有一个强度工况不达标,扭转刚度及弯曲模态均不满足目标要求。然后以5个料厚参数为设计变量,以扭转刚度及模态为响应,进行灵敏度分析,发现U字形截面横梁料厚为扭转刚度及弯曲模态的主要影响因素。即识别出U字截面横梁为强度、扭转刚度及模态的薄弱及敏感区域。针对U字形截面横梁采用Morph方法进行参数化建模,构建4个截面形状参数、1个截面位置参数及1个料厚参数,以不达标的强度工况及扭转刚度及模态为约束,以质量最小为目标,应用Optimus采用差分进化优化算法对后扭力梁进行优化,得到了最优设计方案。经验证,其强度、模态及扭转刚度均满足目标要求,最终达到了重量与性能的平衡。 展开更多
关键词 后扭力梁 参数化建模 morph 多参数优化
原文传递
Association of aphid life stages using DNA sequences: A case study of tribe Eriosomatini (Hemiptera: Aphididae Pemphiginae) 被引量:1
7
作者 He-Cai Zhang Dong Zhang Ge-Xia Qiao 《Insect Science》 SCIE CAS CSCD 2008年第6期545-551,共7页
Association of aphid life stages based on a portion of COI sequence was applied in Eriosomatini. Three aphid specimens, nos. 17496, 19265a, and 19265b collected on Gramineae roots all clustered with Tetraneura chinens... Association of aphid life stages based on a portion of COI sequence was applied in Eriosomatini. Three aphid specimens, nos. 17496, 19265a, and 19265b collected on Gramineae roots all clustered with Tetraneura chinensis Mordvilko with strong support. The average pairwise p-distance among the four taxa was 0.001 (range, 0.000-0.002), and that among all the ingroup taxa was 0.065 (range, 0.000-0.141). This indicated that nos. 17496 and 19265 b were the secondary-host morphs of T. chinensis. In this paper the secondary host morph of T. chinensis is described for the first time. With the identification of more species' secondary-host morphs, aphids identification based on this morph will be made easily. 展开更多
关键词 COI sequence Eriosomatini primary host morph secondary host morph Tetraneura chinensis
原文传递
Microstructure of phases in a Cu–Zr alloy 被引量:2
8
作者 Li-Jun Peng Xu-Jun Mi +2 位作者 Bai-Qing Xiong Hao-Feng Xie Guo-Jie Huang 《Rare Metals》 SCIE EI CAS CSCD 2015年第10期706-709,共4页
The morphology and crystallography of phases in the Cu-0.12% Zr alloy were investigated by scanning electron microscope(SEM), transmission electron microscope(TEM), and high-resolution transmission electron microscope... The morphology and crystallography of phases in the Cu-0.12% Zr alloy were investigated by scanning electron microscope(SEM), transmission electron microscope(TEM), and high-resolution transmission electron microscope(HRTEM). The results show that the as-cast microstructure of Cu–Zr alloy is mainly Cu matrix and eutectic structure which consist of Cu and Cu5Zr phases with a fine lamellar structure. The disk-shaped and plateliked Cu5Zr phases with fcc structure are found in the matrix, in which habit plane is parallel to {111}a plane of the matrix.Between the copper matrix and Cu5Zr phase,there exists an orientation relationship of [112]a|| [011]Cu5Zr;(111)a||(111)Cu5Zr. The space structure model of Cu5Zr phase can be established. 展开更多
关键词 Cu–Zr alloy MICROSTRUCTURE Crystal structure morph
原文传递
Freshwater fungi from karst landscapes in China and Thailand 被引量:1
9
作者 Jing Yang Ling-Ling Liu +8 位作者 EBGareth Jones Kevin D.Hyde Zuo-Yi Liu Dan-Feng Bao Ning-Guo Liu Wen-Li Li Hong-Wei Shen Xian-Dong Yu Jian-Kui Liu 《Fungal Diversity》 SCIE 2023年第2期1-212,共212页
Freshwater fungi comprises a highly diverse group of organisms occurring in freshwater habitats throughout the world.Dur-ing a survey of freshwater fungi on submerged wood in streams and lakes,a wide range of sexual a... Freshwater fungi comprises a highly diverse group of organisms occurring in freshwater habitats throughout the world.Dur-ing a survey of freshwater fungi on submerged wood in streams and lakes,a wide range of sexual and asexual species were collected mainly from karst regions in China and Thailand.Phylogenetic inferences using partial gene regions of LSU,ITS,SSU,TEF1α,and RPB2 sequences revealed that most of these fungi belonged to Dothideomycetes and Sordariomycetes and a few were related to Eurotiomycetes.Based on the morphology and multi-gene phylogeny,we introduce four new genera,viz.Aquabispora,Neocirrenalia,Ocellisimilis and Uvarisporella,and 47 new species,viz.Acrodictys chishuiensis,A.effusa,A.pyriformis,Actinocladium aquaticum,Annulatascus tratensis,Aquabispora setosa,Aqualignicola setosa,Aquimassario-sphaeria vermiformis,Ceratosphaeria flava,Chaetosphaeria polygonalis,Conlarium muriforme,Digitodesmium chishuiense,Ellisembia aquirostrata,Fuscosporella atrobrunnea,Halobyssothecium aquifusiforme,H.caohaiense,Hongkongmyces aquisetosus,Kirschsteiniothelia dushanensis,Monilochaetes alsophilae,Mycoenterolobium macrosporum,Myrmecridium splendidum,Neohelicascus griseoflavus,Neohelicomyces denticulatus,Neohelicosporium fluviatile,Neokalmusia aquib-runnea,Neomassariosphaeria aquimucosa,Neomyrmecridium naviculare,Neospadicoides biseptata,Ocellisimilis clavata,Ophioceras thailandense,Paragaeumannomyces aquaticus,Phialoturbella aquilunata,Pleurohelicosporium hyalinum,Pseudodactylaria denticulata,P.longidenticulata,P.uniseptata,Pseudohalonectria aurantiaca,Rhamphoriopsis aquimi-crospora,Setoseptoria bambusae,Shrungabeeja fluviatilis,Sporidesmium tratense,S.versicolor,Sporoschisma atroviride,Stanjehughesia aquatica,Thysanorea amniculi,Uvarisporella aquatica and Xylolentia aseptata,with an illustrated account,discussion of their taxonomic placement and comparison with morphological similar taxa.Seven new combinations are introduced,viz.Aquabispora grandispora(≡Boerlagiomyces grandisporus),A.websteri(≡Boerlagiomyces 展开更多
关键词 58 new taxa Asexual morph Multi-gene PHYLOGENY Sexual morph TAXONOMY
原文传递
Towards a natural classification of Astrosphaeriella-like species;introducing Astrosphaeriellaceae and Pseudoastrosphaeriellaceae fam.nov.and Astrosphaeriellopsis,gen.nov. 被引量:4
10
作者 Rungtiwa Phookamsak Chada Norphanphoun +9 位作者 Kazuaki Tanaka Dong-Qin Dai Zong-Long Luo Jian-Kui Liu Hong-Yan Su Darbhe J.Bhat Ali H.Bahkali Peter E.Mortimer Jian-Chu Xu Kevin D.Hyde 《Fungal Diversity》 SCIE 2015年第5期143-197,共55页
Astrosphaeriella sensu lato is a common genus occurring on bamboo,palms and stout grasses.Species of Astrosphaeriella have been collected from various countries in tropical,subtropical or temperate regions.In Asia,spe... Astrosphaeriella sensu lato is a common genus occurring on bamboo,palms and stout grasses.Species of Astrosphaeriella have been collected from various countries in tropical,subtropical or temperate regions.In Asia,species have been collected in Brunei,China,Indonesia,Japan,Philippines and Vietnam.There have been several morphological studies on Astrosphaeriella,but molecular work and phylogenetic analyses are generally lacking.Taxa included in Astrosphaeriella were characterized in three main groups 1)typical Astrosphaeriella species(sensu stricto)having carbonaceous,erumpent,conical ascostromata 2)atypical Astrosphaeriella species(sensu lato)having immersed,coriaceous ascostromata with short to long papilla and 3)lophiostoma-like species having immersed ascostromata with slit-like openings.Some of the latter Astrosphaeriella species,having slit-like openings,have been transferred to Fissuroma and Rimora in Aigialaceae.In this study five type specimens of Astrosphaeriella were loaned from herbaria worldwide and re-examined and are re-described and illustrated.Collections of Astrosphaeriella were also made in Thailand and morphologically examined.Pure cultures were obtained from single spores and used in molecular studies.The asexual morph was induced on sterile bamboo pieces placed on water agar.Phylogenetic analyses of combined LSU,SSU and TEF1 sequence data of astrosphaeriella-like species using Bayesian,Maximum parsimony(MP)and Randomized Accelerated Maximum Likelihood(RAxML)analyses were carried out.Phylogenetic analyses show that species of Astrosphaeriella can be distinguished in at least three families.Species of Astrosphaeriella sensu stricto with erumpent,carbonaceous ascostromata,form a strongly supported clade with Pteridiospora species and a new family,Astrosphaeriellaceae,is introduced to accommodate these taxa.The genera are revised and Astrosphaeriella bambusae,A.neofusispora,A.neostellata,A.thailandica,A.thysanolaenae and Pteridiospora chiangraiensis are introduced as new species.Astrosphaeriella 展开更多
关键词 Asexual morph BAMBOO Palm Pseudoastrosphaeriella Phylogeny PLEOSPORALES Taxonomy
原文传递
个性化人脸图像模拟研究 被引量:4
11
作者 胡伟平 邓辉文 《西南大学学报(自然科学版)》 CAS CSCD 北大核心 2014年第2期178-185,共8页
对于任意给定的人脸图像,提出了一个推演任意年龄段人脸图像的个性化模拟方法.利用人脸左右对称的特点设计了一个光照补偿算法;通过几何预处理和灰度预处理,建立归一化的人脸数据库和人脸轮廓库;给定的输入图像经过预处理、特征提取、... 对于任意给定的人脸图像,提出了一个推演任意年龄段人脸图像的个性化模拟方法.利用人脸左右对称的特点设计了一个光照补偿算法;通过几何预处理和灰度预处理,建立归一化的人脸数据库和人脸轮廓库;给定的输入图像经过预处理、特征提取、轮廓变换和纹理合成4个步骤之后得到模拟图像.该方法实现了对任一年龄段、不同生活状况不同胖瘦情况下目标人脸的定制.实验结果表明,该方法对于正面人像有较好的模拟效果. 展开更多
关键词 光照补偿 个性化人脸图像 图形变换 纹理合成
下载PDF
Morphing the Rules:Advanced Adaptations of Mud in Nigerian Buildings
12
作者 Stephen Babatunde Ajadi 《Journal of Civil Engineering and Architecture》 2024年第8期373-383,共11页
Mud is a ubiquitous building material in Nigeria,perhaps this is the reason why it is hardly seen as the outright building material that it is.The most popular contribution of mud to Nigerian architecture can only be ... Mud is a ubiquitous building material in Nigeria,perhaps this is the reason why it is hardly seen as the outright building material that it is.The most popular contribution of mud to Nigerian architecture can only be seen in the ancient traditional huts all over the country.Although still a building material in the suburbs of the country,mud is seen as a relic of the past,a symbol of a primitive tale of Nigerian building construction.The primary effort here is to redefine mud as a“skin”with infinite possibilities of imagery and texture,rather than its typical application as a wall in Nigerian architecture.Mud is attempted to be expressed via a new geometric vocabulary by re-evaluating its surreptitious properties including its ability to behave like a formally defined NURBS(non-uniform rational basis spline)surface.The properties of mud and clay are unconventionally simulated in computer modelling and analysis software to understand the ways in which it can be optimized for advanced building applications.Streamlined calculations and algorithmic calculations serve as tools to discover the NURBS-propensity of mud.This provides a whole new low-cost construction opportunity for the building of irregularly flowing structures. 展开更多
关键词 Comganisms generate morph MUD skin SPLINE texture.
下载PDF
柔性物体变形及动画的实现 被引量:3
13
作者 刘文予 潘晓明 +1 位作者 朱光喜 黄志凌 《华中理工大学学报》 CSCD 北大核心 1996年第8期13-16,共4页
提出了一种任意两个多面体间内插变形的实现方法,并对算法中的具体实现作了较为详细的阐述,其关键是建立两个多面体间的映射关系,给出凹多面体到凸多面体的变换方法,并对球面展开成平面的具体特殊内插问题建立了数学模型。
关键词 变形 内插 三角化 计算机图形学 计算机动画
下载PDF
基于字词联合的变体词规范化研究 被引量:1
14
作者 施振辉 沙灜 +3 位作者 梁棋 李锐 邱泳钦 王斌 《计算机系统应用》 2017年第10期29-35,共7页
社交网络中的文本具有随意性和非正规性等特点,一种常见现象是社交网络文本中存在大量变体词.人们往往为了避免审查、表达情感等将原来的词用变体词替代,原来的词成为目标词.本文研究变体词的规范化任务,即找到变体词所对应的初始目标词... 社交网络中的文本具有随意性和非正规性等特点,一种常见现象是社交网络文本中存在大量变体词.人们往往为了避免审查、表达情感等将原来的词用变体词替代,原来的词成为目标词.本文研究变体词的规范化任务,即找到变体词所对应的初始目标词.本文利用变体词所在文本的时间和语义,结合变体词词性,提出了一种时间和语义结合的方法获取候选目标词,然后提出基于字词联合的词向量方法对候选目标词排序.我们的方法不需要额外的标注数据,实验结果表明,相比于当前最好的方法在准确性上具有一定的提升,针对与目标词存在相同的字的变体词其性能更好. 展开更多
关键词 变体词 变体词规范化 社交网络 词向量 字词联合训练
下载PDF
Hawk mimicry and the evolution of polymorphic cuckoos 被引量:3
15
作者 Rose THOROGOOD Nicholas B.DAVIES 《Chinese Birds》 CSCD 2013年第1期39-50,共12页
The resemblance of some parasitic cuckoos to Accipiter hawks has been known since ancient times. Recent experiments show that the hawk-like features of Common Cuckoos (Cuculus canorus) facilitate access to Reed Warble... The resemblance of some parasitic cuckoos to Accipiter hawks has been known since ancient times. Recent experiments show that the hawk-like features of Common Cuckoos (Cuculus canorus) facilitate access to Reed Warbler (Acrocephalus scirpaceus) host nests. However, social information alerts hosts to see through the cuckoo’s mimetic disguise. In turn, this has promoted the evolution of a cuckoo polymorphism to thwart host recognition. Here we show by comparative analyses that parasitic cuckoos with hawk-like features (yellow eyes, barred underparts, yellow legs) are more likely to be polymorphic (29% of species) than those without (8% of species). Phylogenetic analyses confirm correlated evolution of hawk-like features and cuckoo polymorphism. We suggest that mimicry dynamics are particularly likely to promote the evolution of various guises in parasitic cuckoos to beat host defences. 展开更多
关键词 Batesian mimicry brood parasitism phylogenetic analysis plumage morph POLYmorphISM
下载PDF
Anthostomella is polyphyletic comprising several genera in Xylariaceae 被引量:3
16
作者 Dinushani A.Daranagama Erio Camporesi +4 位作者 Qing Tian Xingzhong Liu Sunita Chamyuang Marc Stadler Kevin D.Hyde 《Fungal Diversity》 SCIE 2015年第4期203-238,共36页
Anthostomella has long been regarded as a large,but polyphyletic genus in the family Xylariaceae,but species in this group generally lack phylogenetic data.In this study,14 anthostomella-like taxa collected from Italy... Anthostomella has long been regarded as a large,but polyphyletic genus in the family Xylariaceae,but species in this group generally lack phylogenetic data.In this study,14 anthostomella-like taxa collected from Italy,were studied using both morphology and molecular data.Single ascospore isolates were obtained and the asexual morphs of five taxa established.The phylogenetic relationships of the xylariaceous taxa were inferred using combined ITS,RPB2,βtubulin and LSU gene regions.We introduce new sequence data for 24 with included the 14 new anthostomella-like taxa.The subfamilies Hypoxyloideae and Xylarioideae within Xylariaceae were recognized as the two major clades with high bootstrap support.Within the two clades 21 subclades were resolved and the anthostomella-like taxa clustered in five of these subclades indicating that the genus is polyphyletic.Anthostomella sensu stricto comprised A.forlicesenica,A.formosa,A.helicofissa,A.rubicola and A.obesa.The A.formosa and A.rubicola collections morphologically closely resemble the type specimens and therefore we designate reference specimens.Three new species Anthostomella helicofissa,A.forlicesenica and A.obesa are also introduced.Four distinct lineages of anthostomella-like taxa correspondent to four new genera,Anthocanalis,Brunneiperidium,Lunatiannulus and Pyriformiascoma,which are also introduced,while one clustered in Astrocystis and is introduced as a new species.Keys to the new anthostomella-like genera and species examined in this study are provided. 展开更多
关键词 Asexual morph Multigene phylogeny Taxonomy Xylariaceous taxa XYLARIALES
原文传递
基于支持向量机(SVM)的汽车车型识别 被引量:3
17
作者 尹玉梅 胡中华 湛金辉 《电子测量技术》 2008年第7期22-25,共4页
本文研究了一种基于支持向量机(SVM)的车型图像识别算法。采用图像边缘检测方法,该方法首先基于邻域灰度极值提取边界候选图像,然后以边界候选像素及其邻域像素的二值模式作为样本集,进行运动目标分割并提取具有RST不变性的轮廓特征向量... 本文研究了一种基于支持向量机(SVM)的车型图像识别算法。采用图像边缘检测方法,该方法首先基于邻域灰度极值提取边界候选图像,然后以边界候选像素及其邻域像素的二值模式作为样本集,进行运动目标分割并提取具有RST不变性的轮廓特征向量,输入支持向量机进行训练和识别。此外,该算法与传统的算法比较,使用核函数少,计算量小,能较好地解决小样本、非线性和局部极小点等问题。实验表明,基于支持向量机(SVM)的车型图像识别算法具有更好的性能。 展开更多
关键词 支持向量机 车型识别 预测
下载PDF
基于Morph功能的改款车模态刚度分析
18
作者 温立志 魏健 郑明锋 《天津职业技术师范大学学报》 2013年第2期13-15,共3页
基于ANSA中的Morph功能,在某改款车型的概念设计阶段,对标杆车的有限元模型进行快速的结构调整,通过仿真手段,对改款车的模态刚度进行分析;然后,对原型车白车身结构进行模态实验,获取其模态频率及对应振型,进而与改款车进行对比,提前对... 基于ANSA中的Morph功能,在某改款车型的概念设计阶段,对标杆车的有限元模型进行快速的结构调整,通过仿真手段,对改款车的模态刚度进行分析;然后,对原型车白车身结构进行模态实验,获取其模态频率及对应振型,进而与改款车进行对比,提前对改款车结构的合理性做出评价。 展开更多
关键词 morph 概念设计 模态 刚度
下载PDF
Development and Characterization of Microsatellite Markers for Three Pollination Morphs of <i>Cimicifuga simplex</i>(Ranunculaceae)
19
作者 Tsubasa Toji Yoshiaki Kameyama +1 位作者 Akira S. Hirao Takao Itino 《American Journal of Plant Sciences》 2018年第4期599-605,共7页
Cimicifuga simplex Wormsk. (Ranunculaceae) is a perennial herb distributed in eastern and northeastern Asia for which at least three different pollination morphs have been reported. It is classified as endangered or n... Cimicifuga simplex Wormsk. (Ranunculaceae) is a perennial herb distributed in eastern and northeastern Asia for which at least three different pollination morphs have been reported. It is classified as endangered or near threatened in some Japanese regions, and its rhizome is commercially used as a crude drug. To examine genetic differentiation and gene flow among the three morphs, we developed eight microsatellite markers by using next-generation sequencing and estimated the genetic structure of C. simplex. We tested eight primer pairs on 93 individuals from six populations of C. simplex in Nagano, central Japan, and found that heterozygosity in morphs I and III was low compared to expected heterozygosity. Bayesian clustering performed with the STRUCTURE program clearly distinguished the three morphs of C. simplex, and only a little gene flow was detected among the morphs. These eight microsatellite markers are expected to be useful in conservation genetic studies of this species and for future conservation planning. 展开更多
关键词 CIMICIFUGA SIMPLEX Genetic Structure Microsatellite Marker Next-Generation Sequencing POLLINATION morph
下载PDF
Adaptive associations between total body color dimorphism and climatic stress-related traits in a stenothermal circumtropical Drosophila species
20
作者 Ravi Parkash Jyoti Chahal +1 位作者 Vineeta Sharma Kapil Dev 《Insect Science》 CAS CSCD 2012年第2期247-262,共16页
Low desiccation resistance of Drosophila ananassae reflects its rarity outside the humid tropics. However, the ability of this sensitive species to evolve under seasonally varying subtropical areas is largely unknown.... Low desiccation resistance of Drosophila ananassae reflects its rarity outside the humid tropics. However, the ability of this sensitive species to evolve under seasonally varying subtropical areas is largely unknown. D. ananassae flies are mostly lighter during the rainy season but darker and lighter flies occur in the autumn season in northern India. We tested the hypothesis whether seasonally varying alternative body color phenotypes of D. ananassae vary in their levels of environmental stress tolerances and mating behavior. Thus, we investigated D. ananassae flies collected during rainy and autumn seasons for changes in body melanization and their genetic basis, desiccation-related traits, cold tolerance and mating propensity. On the basis of genetic crosses, we found total body color dimorphism consistent with a single gene model in both sexes olD. ananassae. A significant increase in the frequency of the dark morph was observed during the drier autumn season, and body color phenotypes showed significant deviations from Hardy-Weinberg equilibrium, which suggests climatic selection plays a role. Resistance to desiccation as well as cold stress were two- to three-fold higher in the dark body color strain as compared with the light strain. On the basis of no-choice mating experiments, we observed significantly higher assortative matings between dark morphs under desiccation or cold stress, and between light morphs under hot or higher humidity conditions. To the best of our knowledge, this is the first report on the ecological significance of seasonally varying total body color dimorphism in a tropical species, D. ananassae. 展开更多
关键词 assortative matings cold tolerance dark and the light morph desiccation resistance Drosophila ananassae seasonal adaptations
原文传递
上一页 1 2 13 下一页 到第
使用帮助 返回顶部