检索结果-南通市图书馆

Ca^(2+) signals induced from calcium stores in pancreatic islet β cells

Chinese science Bulletin 2000年第1期45卷 51-56页

作者： ZENG Xuhui, QU Anlian, LOU Xuelin, XU Jianhua, WANG Junjian, WU Hongxiu & zhou zhuan.. Institute of Biochemistry and Biophysics, Huazhong university of {3. and technology, Wuhan 43.074, China 2. Pharmacology, Huazhong university of {3. and technology, Wuhan 43.074, China 3. school of life sciences, university of {3. and technology of China, hefei 2.002., China {13. should be addressed to zhou zhuan. Institute of Biochemistry and Biophysics Huazhong University of Science and Technology Wuhan China Pharmacology Huazhong University of Science and Technology Wuhan China school of life sciences University of Science and Technology of China Hefei China

In single rat pancreatic βcells, using fura-2 microfluorometry to measure [Ca2+] response upon different stimuli, the ways of calcium regulation have been studied. When the extracellular calcium concentration was 2.5 mmol/L, either 60 mmol/L KCI, 20 mmol/L D-glucose or 0.1 mmol/L tolbutamide induced increase in [Ca2+]. Such increase in [Ca2+] was absent when the same stimuli were applied under zero extracellular calcium. These results indicate that the increase of [Ca2+] is induced by the activation of voltage-dependent calcium channels in p celis. The manifold forms of [Ca2+] change induced by glucose imply that the effects of glucose are complex. 5 mmol/L caffeine or 5 mmol/L MCh increase the [Ca2+], which is independent of the external calcium, suggesting that [Ca2+] can be regulated by Ca2+ release from not only the IP3.sensitive but also the ryanodine sensitive calcium stores in p celis. The latency of Ca responses for IP3.pathway (5 s) is faster than that for ryanodine pathway (3. s), it is

关键词： pancreatic β cell [Ca2+]i calcium stores glucose fura-2.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Detection and parameter estimation of multicomponent LFM signal based on the fractional Fourier transform

引用

science in China(Series F) 2004年第2期47卷 184-198页

作者： QI Lin1, 2, TAO Ran1, zhou Siyong1 & WANG Yue1 1. Department of Electronic Engineering, Beijing Institute of technology, Beijing 100081, China 2. school of Information Engineering, Zhengzhou university, Zhengzhou 450052, China correspondence should be addressed to QI Lin (email: qilin@***) 1. Department of Electronic Engineering Beijing Institute of Technology 100081 Beijing China 2. school of Information Engineering Zhengzhou University 450052 Zhengzhou China

This paper presents a new method for the detection and parameter estimation of multicomponent LFM signals based on the fractional Fourier transform. For the optimization in the fractional Fourier domain, an algorithm based on Quasi-Newton method is proposed which consists of two steps of searching, leading to a reduction in computation without loss of accuracy. And for multicomponent signals, we further propose a signal separation technique in the fractional Fourier domain which can effectively suppress the interferences on the detection of the weak components brought by the stronger components. The statistical analysis of the estimate errors is also performed which perfects the method theoretically, and finally, simulation results are provided to show the validity of our method.

关键词： LFM signal parameter estimation fractional Fourier transform.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Non-Metric CCD Camera Calibration Algorithm in a Digital Photogrammetry System

引用

Journal of China university of Mining and technology 2006年第2期16卷 119-122页

作者： YANG Hua-chao DENG Ka-zhong ZHANG Shu-bi GUO Guang-li zhou Ming school of Environment and Spatial lnformatics China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3. information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation （DLT） and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3.pixels respectivelv, which can meet the requirements of close-range photogrammetry with high accuracy.

关键词： direct linear transformation collinearity equation bundle adjustment camera calibration Hough transformation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：