期刊文献+
共找到11篇文章
< 1 >
每页显示 20 50 100
中国传统大菊叶片形态的数量化定义与分类 被引量:5
1
作者 宋雪彬 高康 +3 位作者 黄河 刘芷兰 戴思兰 嵇彧 《植物学报》 CAS CSCD 北大核心 2021年第1期10-24,共15页
中国传统大菊品种叶片形态变异丰富,然而至今仍未对其进行科学的定义和分类,无法有效利用这些形态性状进行品种鉴定和叶形遗传解析。利用数量化分析方法对植物形态进行定义和分类,是植物性状遗传解析的前提。对436个中国传统大菊品种的2... 中国传统大菊品种叶片形态变异丰富,然而至今仍未对其进行科学的定义和分类,无法有效利用这些形态性状进行品种鉴定和叶形遗传解析。利用数量化分析方法对植物形态进行定义和分类,是植物性状遗传解析的前提。对436个中国传统大菊品种的24个叶形性状进行重新定义及观测,通过相关性分析确定了8个相对独立的性状,用变异系数及主成分分析等数量化分析方法筛选出叶长/叶宽、叶片最宽处所在位置/叶长、右下裂片长/右下叶脉长、右下裂片长/右下裂片宽及叶柄长/全叶长5个相对独立且关键的叶部性状。利用这5个性状,通过Q聚类分析,最终将菊花(Chrysanthemum×morifolium)叶片分为16种叶型。研究结果为菊花品种鉴定提供了有效的叶部评价标准,并建立了中国传统菊花品种叶片数量化定义和分类体系,也为观赏植物复杂性状的解析提供了新方法。 展开更多
关键词 中国传统大菊 叶片形态 形态特征 量化定义 分类
原文传递
地质绘图符号矢量化标准研究与应用 被引量:1
2
作者 张全 陈可为 《信息系统工程》 2015年第9期80-81,共2页
本文在对《SY/T 6931石油地质绘图软件符号规范》石油行业标准深入研究的基础上,讲述了该标准制定的目的、意义、与已有标准的关系及标准所包含的符号矢量化定义。并详细介绍了基于该标准的符号制定、编辑、共享系统的设计与实现。
关键词 绘图符号标准 符号矢量化定义 符号编辑器 XML
下载PDF
关于极限“ε-”定义的教学
3
作者 谢效训 《枣庄师专学报》 2000年第5期99-100,共2页
论述了函数“ε-”定义的重要性及其教学困难 ,研究了“ε-”
关键词 函数 极限 定义 数学分析 教学方法 量化定义 分析定义
下载PDF
在JPEG压缩算法中选择量化表的尝试
4
作者 智艾娣 智西湖 《小型微型计算机系统》 CSCD 北大核心 1997年第9期73-76,共4页
数字化后的图像包含着巨大的数据量,在多媒体技术中数据压缩便显得尤为重要。本文对JPEG压缩算法进行探讨,通过自定义的量化表进行数据压缩,取得了优于JPEG推荐的量化表的效果。
关键词 JPEG 压缩算法 定义量化 多媒体
下载PDF
cs*-regular Families and Metrization Theorems
5
作者 LI Ke-dian XU Hua-wei 《Chinese Quarterly Journal of Mathematics》 CSCD 2009年第4期609-613,共5页
In this paper, we proved that a sequential space has a cs*-regular cs*-network (or a cs*-regular weak base) is metrizable, which generalized related results in [6], [12] and [14].
关键词 cs*-regular families NETWORK weak base metrizable spaces
下载PDF
Expression of ABCG2 in human gastric carcinoma
6
作者 NingWang Lin Chen Bo Wei Wei Zheng 《The Chinese-German Journal of Clinical Oncology》 CAS 2010年第3期145-148,共4页
Objective:The aim of this study was to investigate the expression of ABCG2 in human gastric carcinoma and its clinical significance.Methods:Expression of ABCG2 was examined with immunohistochemical technique in the sp... Objective:The aim of this study was to investigate the expression of ABCG2 in human gastric carcinoma and its clinical significance.Methods:Expression of ABCG2 was examined with immunohistochemical technique in the specimens from 45 gastric carcinoma tissues and 30 surrounding normal tissues.The mRNA expression of ABCG2 was measured by RT-PCR and real-time quantitative PCR in 30 cases of gastric carcinoma and normal gastric mucosa, respectively.Results:ABCG2 expression was observed in 28 of 45(62.2%) cases by immunohistochemical analysis.In ABCG2-positive tumors, adjacent non-neoplastic tissue was similarly analyzed, revealed that ABCG2 was up-regulated in gastric carcinoma.ABCG2 expression in poorly differentiated/undifferentiated carcinoma was significantly higher than that in well/moderately-differentiated carcinoma(P < 0.05).The mRNA expression of ABCG2 was significantly higher than that in normal gastric mucosa(P < 0.05).Conclusion:ABCG2 plays an important role in the multi-drug resistance of gastric carcinoma.ABCG2 might be an important factor in the research of gastric cancer stem cell. 展开更多
关键词 gastric carcinoma ABCG2 multi-drug resistance side population cancer stem cell
下载PDF
Mexican Identity on YouTube: A Youngsters' User Approach
7
作者 Jacob Banuelos 《Journalism and Mass Communication》 2013年第3期141-153,共13页
The work at hand analyzes the visibility of cultural identity of"Mexico" on the YouTube platform (Retrieved from http://www.youtube.com). It is focused on qualitative and quantitative analyses of a sampling of 80... The work at hand analyzes the visibility of cultural identity of"Mexico" on the YouTube platform (Retrieved from http://www.youtube.com). It is focused on qualitative and quantitative analyses of a sampling of 80 videos that appear when the word "Mexico" is applied in various search formats within the site itself. User profile is also analyzed, along with video title, labels, date of upload, length, view count, thematic category, and commentaries. From this sampling of videos, an analysis is made upon the cultural identity of "Mexico" within a postmodernist framework of multicultural, fragmented, and decentralized identities (Friedman, 1994), parting from the theory of cultural hybridization (Pieterse, 2004), and under the logic of a media convergent culture (Jenkins, 2004a). 展开更多
关键词 YOUTUBE Mexico cultural identity postmodemism HYBRIDIZATION social network
下载PDF
A generalized L_2-discrepancy for cubature and uncertainty quantification of nonlinear structures 被引量:2
8
作者 CHEN Jian Bing SONG Peng Yan 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第6期941-952,共12页
The numerical method for multi-dimensional integrals is of great importance, particularly in the uncertainty quantification of engineering structures. The key is to generate representative points as few as possible bu... The numerical method for multi-dimensional integrals is of great importance, particularly in the uncertainty quantification of engineering structures. The key is to generate representative points as few as possible but of acceptable accuracy. A generalized L2(GL2)-discrepancy is studied by taking unequal weights for the point set. The extended Koksma-Hlawka inequality is discussed. Thereby, a worst-case error estimate is provided by such defined GL2-discrepancy, whose dosed-form expression is available. The characteristic values of GL2-discrepancy are investigated. An optimal strategy for the selection of the representative point sets with a prescribed cardinal number is proposed by minimizing the GL2-discrepancy. The three typical examples of the multi-dimensional integrals are investigated. The stochastic dynamic response analysis of a nonlinear structure is then studied by incorporating the proposed method into the probability density evolution method. It is shown that the proposed method is advantageous in achieving tradeoffs between the efficiency and accuracy of the exemplified problems. Problems to be further studied are discussed. 展开更多
关键词 Koksma-Hlawka inequality CUBATURE L2-discrepancy nonlinear structure stochastic dynamics
原文传递
A note on finite abelian covers
9
作者 GAO Yun 《Science China Mathematics》 SCIE 2011年第7期1333-1342,共10页
We prove that any abelian cover over a smooth variety is defined by some cyclic equations. From the defining equations, we compute explicitly the normalization, branch locus, ramification indices, global invariants, a... We prove that any abelian cover over a smooth variety is defined by some cyclic equations. From the defining equations, we compute explicitly the normalization, branch locus, ramification indices, global invariants, and the resolution of singularities. As an application, we construct a new algebraic surface which is the quotient of ball. 展开更多
关键词 abelian cover NORMALIZATION IRREGULARITY the quotient of ball
原文传递
The Well-Posedness for Generalized Fuzzy Games
10
作者 WANG Nengfa YANG Zhe 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2017年第4期921-931,共11页
This paper establishes the stable results for generalized fuzzy games by using a nonlinear scalarization technique. The authors introduce some concepts of well-posedness for generalized fuzzy games. Moreover, the auth... This paper establishes the stable results for generalized fuzzy games by using a nonlinear scalarization technique. The authors introduce some concepts of well-posedness for generalized fuzzy games. Moreover, the authors identify a class of generalized fuzzy games such that every element of the collection is generalized well-posed, and there exists a dense residual subset of the collection, where every generalized fuzzy game is robust well-posed. 展开更多
关键词 Generalized fuzzy game nonlinear scalarization function well-posedness.
原文传递
Quantization of Space in the Presence of a Minimal Length
11
作者 王伦舟 龙超云 隆正文 《Communications in Theoretical Physics》 SCIE CAS CSCD 2015年第6期709-714,共6页
In this article, we apply the Generalized Uncertainty Principle (GUP), which is consistent with quantum gravity theories to an elementary particle in a finite potential well, and study the quantum behavior in this s... In this article, we apply the Generalized Uncertainty Principle (GUP), which is consistent with quantum gravity theories to an elementary particle in a finite potential well, and study the quantum behavior in this system. The generalized Hamiltonian contains two additional terms, which are proportional to ap3 (the result of the maximum momentum assumption) and a2p4 (the result of the minimum length assumption), where a - 1/MpIc is the GUP parameter. On the basis of the work by Ali et al., we solve the generaiized Schrodinger equation which is extended to include the a2 correction term, and find that the length L of the finite potentiai well must be quantized. Then a generalization to the double-square-well potential is discussed. The result shows that all the measurable lengths especially the distance between the two potential wells are quantized in units of aolp1 in GUP scenario. 展开更多
关键词 finite potential well minimal length generalized uncertainty principle
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部