期刊文献+
共找到78篇文章
< 1 2 4 >
每页显示 20 50 100
Hilbert C*-模H中标准框架的刻画
1
作者 姚喜妍 《中北大学学报(自然科学版)》 EI CAS 2006年第2期168-170,共3页
应用A-值线性算子T:H→l2(A),刻画了H中标准框架、正规紧标准框架及两个互为对偶的标准框架,讨论了A-值线性、有界、可逆及正的框架算子S=T*T的等价性质,证明了模H的标准框架与它的典型对偶标准框架是正规紧标准框架的充分必要条件是框... 应用A-值线性算子T:H→l2(A),刻画了H中标准框架、正规紧标准框架及两个互为对偶的标准框架,讨论了A-值线性、有界、可逆及正的框架算子S=T*T的等价性质,证明了模H的标准框架与它的典型对偶标准框架是正规紧标准框架的充分必要条件是框架算子S=I. 展开更多
关键词 c*-代数 HILBERT c*-模框架 标准框架 框架算子
下载PDF
准HilbertC*-模上保正交映射的稳定性
2
作者 孔亮 《商洛学院学报》 2011年第4期6-9,共4页
对于准Hilbert C*-模之间的ε-近似保正交A-线性映射T,得到了‖〈T(x),T(y)〉-||T||2〈x,y〉‖的一个估计,研究了保正交A-线性映射在"ε-近似保正交"意义下的稳定性,给出了准Hilbert C*-模之间的A-线性映射是ε-近似保正交A-... 对于准Hilbert C*-模之间的ε-近似保正交A-线性映射T,得到了‖〈T(x),T(y)〉-||T||2〈x,y〉‖的一个估计,研究了保正交A-线性映射在"ε-近似保正交"意义下的稳定性,给出了准Hilbert C*-模之间的A-线性映射是ε-近似保正交A-线性映射的一些充分条件。 展开更多
关键词 准Hilbert c*-模 ε-近似保正交映射 稳定性
下载PDF
Hilbert C*-模上的算子值框架及分解
3
作者 徐盛馀 孟彬 李丹 《西安文理学院学报(自然科学版)》 2010年第4期1-4,共4页
已知A是含单位的C*-代数,在文中仅在标准模HA=l2(A),以及其子模H0上讨论,主要给出了判定某序列{Aj}j∈J B(HA,H0)是算子值框架的一个等价命题,以及利用算子理论中有关算子的分解,从而得到框架的相关分解的命题.
关键词 HILBERT c*-模 框架 分解
下载PDF
Hilbert C* -模中g^-框架的新的等式和不等式 被引量:4
4
作者 相中启 张慧慧 《上饶师范学院学报》 2016年第3期6-9,共4页
利用算子理论方法给出了Hilbert C*-模中g-框架的新的等式和不等式,所得结果包含了已知的一些结果。
关键词 HILBERT c*-模 G-框架 等式 不等式
下载PDF
Hilbert C*-模上的广义g-框架 被引量:1
5
作者 靳世华 孟彬 肖秀梅 《数学进展》 CSCD 北大核心 2011年第1期95-102,共8页
本文主要研究了Hilbert C*-模上广义g-框架.给出了Hilbert C*-模上的广义g-框架,广义g-框架算子,广义典则对偶g-框架及广义交错对偶g-框架的定义,并证明了有关广义g-框架的一些结果.
关键词 HILBERT c*-模 广义g-框架 广义g-框架算子 广义对偶g-框架
原文传递
多重C*-动力系统在HilbertC*-模上的膨胀 被引量:1
6
作者 王中华 张建华 《数学学报(中文版)》 CSCD 北大核心 2016年第6期859-864,共6页
研究了多重 C*-动力系统在Hilbert C*-模上表示的膨胀.设(A,α)是一个多重C*-动力系统,(π,T,E)是(A,α)的行压缩协变表示,证明了存在(π,T,E)的等距膨胀(ρ,V,F).
关键词 膨胀 协变表示 多重c*-动力系统 HILBERT c*-模
原文传递
Hilbert C*-模中g-框架的一些性质 被引量:1
7
作者 姚喜妍 《数学学报(中文版)》 SCIE CSCD 北大核心 2011年第1期1-8,共8页
本文运用算子理论方法,给出Hilbert C*-模中g-框架的一些性质并讨论g-框架的扰动性,得到g-框架的和的一些刻画,所得结果推广和改进了已有的结果.
关键词 HILBERT c*-模 G-框架 g-框架算子
原文传递
Hilbert C~*-模中g-Riesz基的新刻画 被引量:1
8
作者 相中启 《湖南师范大学自然科学学报》 CAS 北大核心 2017年第6期80-86,共7页
利用算子理论方法证明了Hilbert C~*-模上的可伴算子序列是g-Riesz基且有唯一对偶g-框架当且仅当相应的合成算子是一线性同胚,这修正了已有的一个结论.进一步,作为该结果的直接应用,给出了Hilbert C~*-模中的g-Riesz基具有唯一对偶g-框... 利用算子理论方法证明了Hilbert C~*-模上的可伴算子序列是g-Riesz基且有唯一对偶g-框架当且仅当相应的合成算子是一线性同胚,这修正了已有的一个结论.进一步,作为该结果的直接应用,给出了Hilbert C~*-模中的g-Riesz基具有唯一对偶g-框架的保界等价刻画. 展开更多
关键词 HILBERT c*-模 G-框架 g-Riesz基 对偶g-框架
下载PDF
Hilbert C*-模中融合框架的新定义及其系数的最小性
9
作者 相中启 李永明 《兰州大学学报(自然科学版)》 CAS CSCD 北大核心 2016年第2期258-261,265,共5页
观察到Hilbert C*-模中融合框架原定义的不合理性,通过权重集的选取将其改进,得到融合框架的新定义并给出了新定义的等价形式.得到了Hilbert C*-模中融合框架系数的一个最小性质,作为该性质的应用,给出了融合框架去掉某个框架元素后不... 观察到Hilbert C*-模中融合框架原定义的不合理性,通过权重集的选取将其改进,得到融合框架的新定义并给出了新定义的等价形式.得到了Hilbert C*-模中融合框架系数的一个最小性质,作为该性质的应用,给出了融合框架去掉某个框架元素后不再成为融合框架的条件. 展开更多
关键词 HILBERT c*-模 融合框架 新定义 等价定义 最小性
下载PDF
可伴算子保持Hilbert C~*-模中g-框架的充要条件
10
作者 相中启 喻晓 +1 位作者 袁邓彬 黄飞鸿 《上饶师范学院学报》 2017年第3期7-10,共4页
利用算子理论方法证明了可伴算子保持Hilbert C~*-模中的g-框架当且仅当它是单射且有闭的值域,这修正了已有的一个结果。
关键词 HILBERT c*-模 G-框架 可伴算子 闭值域
下载PDF
ALLIED FUZZY c-MEANS CLUSTERING MODEL 被引量:2
11
作者 武小红 周建江 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2006年第3期208-213,共6页
A novel model of fuzzy clustering, i.e. an allied fuzzy c means (AFCM) model is proposed based on the combination of advantages of fuzzy c means (FCM) and possibilistic c means (PCM) clustering. PCM is sensitive... A novel model of fuzzy clustering, i.e. an allied fuzzy c means (AFCM) model is proposed based on the combination of advantages of fuzzy c means (FCM) and possibilistic c means (PCM) clustering. PCM is sensitive to initializations and often generates coincident clusters. AFCM overcomes this shortcoming and it is an ex tension of PCM. Membership and typicality values can be simultaneously produced in AFCM. Experimental re- suits show that noise data can be well processed, coincident clusters are avoided and clustering accuracy is better. 展开更多
关键词 fuzzy c-means clustering possibilistic c means clustering allied fuzzy c-means clustering
下载PDF
Fuzzy c-means text clustering based on topic concept sub-space 被引量:3
12
作者 吉翔华 陈超 +1 位作者 邵正荣 俞能海 《Journal of Southeast University(English Edition)》 EI CAS 2007年第3期439-442,共4页
To improve the accuracy of text clustering, fuzzy c-means clustering based on topic concept sub-space (TCS2FCM) is introduced for classifying texts. Five evaluation functions are combined to extract key phrases. Con... To improve the accuracy of text clustering, fuzzy c-means clustering based on topic concept sub-space (TCS2FCM) is introduced for classifying texts. Five evaluation functions are combined to extract key phrases. Concept phrases, as well as the descriptions of final clusters, are presented using WordNet origin from key phrases. Initial centers and membership matrix are the most important factors affecting clustering performance. Orthogonal concept topic sub-spaces are built with the topic concept phrases representing topics of the texts and the initialization of centers and the membership matrix depend on the concept vectors in sub-spaces. The results show that, different from random initialization of traditional fuzzy c-means clustering, the initialization related to text content contributions can improve clustering precision. 展开更多
关键词 TcS2FcM topic concept space fuzzy c-means clustering text clustering
下载PDF
An Introduction to the Theory of C~*-modules
13
作者 邓宏钧 刘德权 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第2期72-77,共6页
This paper,combined algebraical structure with analytical system,has studied the part of theory of C~*-modules over A by using the homolgical methods, where A is a commutative C~*-algebra over complex number field C. ... This paper,combined algebraical structure with analytical system,has studied the part of theory of C~*-modules over A by using the homolgical methods, where A is a commutative C~*-algebra over complex number field C. That is to say we have not only defined some relevant new concept,but also obtained some results about them. 展开更多
关键词 commutative c~*-algebra c~*-module c~*-homomorphism
下载PDF
NEW SHADOWED C-MEANS CLUSTERING WITH FEATURE WEIGHTS 被引量:2
14
作者 王丽娜 王建东 姜坚 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第3期273-283,共11页
Partition-based clustering with weighted feature is developed in the framework of shadowed sets. The objects in the core and boundary regions, generated by shadowed sets-based clustering, have different impact on the ... Partition-based clustering with weighted feature is developed in the framework of shadowed sets. The objects in the core and boundary regions, generated by shadowed sets-based clustering, have different impact on the prototype of each cluster. By integrating feature weights, a formula for weight calculation is introduced to the clustering algorithm. The selection of weight exponent is crucial for good result and the weights are updated iteratively with each partition of clusters. The convergence of the weighted algorithms is given, and the feasible cluster validity indices of data mining application are utilized. Experimental results on both synthetic and real-life numerical data with different feature weights demonstrate that the weighted algorithm is better than the other unweighted algorithms. 展开更多
关键词 fuzzy c-means shadowed sets shadowed c-means feature weights cluster validity index
下载PDF
Helicobacter Pylori-induced Gastritis Model in BALB/c Mice Infected With Fresh Isolates from a Human Complex Ulcer Patient 被引量:1
15
作者 阮国瑞 史俊华 +5 位作者 张雪萍 陈平圣 尹克铮 葛培玲 许曼华 许祥熹 《Journal of Chinese Pharmaceutical Sciences》 CAS 2002年第2期43-47,共5页
A useful helicobacter pylori-induced gastritis model using BALB/c mice was established for mimicking of human gastritis induced by Helicobacter pylori (H. pylori). The H. pylori isolates were obtained freshly from a... A useful helicobacter pylori-induced gastritis model using BALB/c mice was established for mimicking of human gastritis induced by Helicobacter pylori (H. pylori). The H. pylori isolates were obtained freshly from a human complex ulcer patient. BALB/c mice were fasted for 24 h and then 0.25 mL of 0.2 mol·L -1 NaHCO 3 was administered after by gavage to each mouse and 0.5 mL of 10 9 colonies formation unit per milliliter (CFU/mL) of H. pylori was administered 15 min. On the 3 rd day and 5 th day, the H. pylori inoculations were repeated. The inoculated mice were sacrificed in batch on the 5 th day, in the 2 nd week, 3 rd week and 4 th week. The gastric mucous membrane near pyloric portion was removed, treated and then cultured under microaerobic condition for detection of H.pylori. The remainders of the gastric membrane were fixed by 10% formaldehyde solution for pathological detection. The results showed that the H. pylori could be separated from the gastric membranes of inoculated mice. Obvious invasion of inflammatory cells in the gastric membranes of inoculated mice could be observed from pathological sections. It can be concluded that the inoculating fresh human H. pylori isolates can produce mouse gastritis. This model of BALB/c mice can be used for evaluating the therapeutic agents for the treatment of gastritis induced by H. pylori. 展开更多
关键词 Helicobacter pylori GASTRITIS BALB/c mice
下载PDF
Information Entropy Squeezing for a Atom in Mode-Mode Competition System 被引量:2
16
作者 WU Qin FANG Mao-Fa +2 位作者 LI Shao-Xin LI Ying HU Yao-Hua 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第12期1411-1416,共6页
The entropy squeezing properties for a two-level atom interacting with a two-mode field via two differentcompeting transitions are investigated from a quantum information point of view.The influences of the initial st... The entropy squeezing properties for a two-level atom interacting with a two-mode field via two differentcompeting transitions are investigated from a quantum information point of view.The influences of the initial state of thesystem and the relative coupling strength between the atom and the field on the atomic information entropy squeezingare discussed.Our results show that the squeezed direction and the frequency of the information entropy squeezing canbe controlled by choosing the phase of the atom dipole and the relative competing strength of atom-field,respectively.We find that,under the same condition,no atomic variance squeezing is predicted from the HUR while optimal entropysqueezing is obtained from the EUR,so the quantum information entropy is a remarkable precision measure for theatomic squeezing in the considered system. 展开更多
关键词 mode-mode competition model information entropy squeezing variance squeezing information entropy uncertainty relation
下载PDF
Differentiation between malignant and benign nodules in the liver: Use of contrast C^3-MODE technology 被引量:7
17
作者 Bao-MingLuo Yan-LingWen Hai-YunYang HuiZhi BingOu Jian-HongMa Jing-ShengPan Xiao-NingDai 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第16期2402-2407,共6页
AIM: To investigate the value of contrast-enhanced C3-MODE technology in differentiating malignant nodules of liver from the benign ones. METHODS: Forty-six nodules in 36 patients (29 men and 7 women) were studied by ... AIM: To investigate the value of contrast-enhanced C3-MODE technology in differentiating malignant nodules of liver from the benign ones. METHODS: Forty-six nodules in 36 patients (29 men and 7 women) were studied by contrast-enhanced C3-MODE technology and contrast-enhanced CT in 1 wk before the biopsy or operation. A low MI monitor and a high MI flash imaging were intermittently performed. After the injection of contrast agent, the period from 10 to 30 s and the time later than 100 s were respectively defined as early arterial phase and the late phase. The vascularities of the liver nodules in the two phases were combined for differential diagnosis. Corresponding to the pathological diagnosis, the accuracy, sensitivity and specificity of contrast-enhanced C3-MODE technology were compared to those of contrast-enhanced CT. RESULTS: By C3-MODE technology, 33 of the 46 liver nodules were demonstrated as defected area in the late phase and were diagnosed as malignant tumors. Of them, 28 with hypervascularity in the early arterial phase were assessed as hepatocellular carcinoma, the other five nodules with rim-like enhancement in the early arterial phase were diagnosed as metastatic tumors. Thirteen nodules were shown as iso or hypervascularity in the late phase as well as centripetal filling in the early arterial phase and we made a diagnosis of hemangioma. Corresponding to the pathological results, the sensitivity, specificity and accuracy of contrast-enhanced C3-MODE technology in differentiating malignant and benign nodules in the liver were 97.0%, 92.3% and 95.7%, respectively. With comparison to those of contrast CT (sensitivity, 94.1%; specificity, 91.7%; accuracy, 93.5%), the difference was not significant. CONCLUSION: Contrast-enhanced C3-MODE technology can effectively differentiate malignant liver tumors from the benign nodules. It highly agrees diagnostically with the pathology. We suggest that it provides a new approach for differential diagnosis of liver nodules in addition to contrast-enhanced CT. 展开更多
关键词 contrast medium Harmonic imaging Hepatic nodule Ultrasound
下载PDF
Probe in college English teaching in Grade-C class
18
作者 赵堃 《Sino-US English Teaching》 2007年第8期23-26,共4页
College English is not only an essential curriculum of language, but also is an extremely important curriculum of cultural in college education. As a result of various factors, there are individual differences in coll... College English is not only an essential curriculum of language, but also is an extremely important curriculum of cultural in college education. As a result of various factors, there are individual differences in college students' English study. Therefore, to gradually improve all the students' English, graded teaching becomes the best choice. In this thesis, graded teaching will be studied from several respects. And I hope it can give some slight help to some of college teachers. 展开更多
关键词 graded teaching Grade-c class learning motive teaching mode
下载PDF
Watershed classification by remote sensing indices: A fuzzy c-means clustering approach 被引量:10
19
作者 Bahram CHOUBIN Karim SOLAIMANI +1 位作者 Mahmoud HABIBNEJAD ROSHAN Arash MALEKIAN 《Journal of Mountain Science》 SCIE CSCD 2017年第10期2053-2063,共11页
Determining the relatively similar hydrological properties of the watersheds is very crucial in order to readily classify them for management practices such as flood and soil erosion control. This study aimed to ident... Determining the relatively similar hydrological properties of the watersheds is very crucial in order to readily classify them for management practices such as flood and soil erosion control. This study aimed to identify homogeneous hydrological watersheds using remote sensing data in western Iran. To achieve this goal, remote sensing indices including SAVI, LAI, NDMI, NDVI and snow cover, were extracted from MODIS data over the period 2000 to 2015. Then, a fuzzy method was used to clustering the watersheds based on the extracted indices. A fuzzy c-mean(FCM) algorithm enabled to classify 38 watersheds in three homogeneous groups.The optimal number of clusters was determined through evaluation of partition coefficient, partition entropy function and trial and error. The results indicated three homogeneous regions identified by the fuzzy c-mean clustering and remote sensing product which are consistent with the variations of topography and climate of the study area. Inherently,the grouped watersheds have similar hydrological properties and are likely to need similar management considerations and measures. 展开更多
关键词 Karkheh watershed Fuzzy c-means clustering Watershed classification Homogeneous sub-watersheds
下载PDF
"Pseudo-invariant Eigen-operator" Method for Deriving Energy-Gap of an Atom-Cavity Jaynes-Cummings Hamiltonian with Atomic Centre-of-Mass Motion
20
作者 FAN Hong-Yi TANG Xu-Bing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第6期1003-1006,共4页
Using the "pseudo-invariant eigen-operator" method we find the energy-gap of the Jaynes-Cummings Hamiltonian model of an atom-cavity system. This model takes the atomic centre-of-mass motion into account. The supers... Using the "pseudo-invariant eigen-operator" method we find the energy-gap of the Jaynes-Cummings Hamiltonian model of an atom-cavity system. This model takes the atomic centre-of-mass motion into account. The supersymmetric structure is involved in the Hamiltonian of an atom-cavity system. By selecting suitable supersymmettic generators and using supersymmetrie transformation the Hamiltonian is diagonalized and energy eigenvectors are obtained. 展开更多
关键词 J-c model with atom motion supersymmetric transform pseudo-invariant eigen-operator
下载PDF
上一页 1 2 4 下一页 到第
使用帮助 返回顶部