检索结果-南通市图书馆

Singularity detection of the rabbit electrocardiogram:An evolutionary spectral method

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2009年第10期19卷 1317-1326页

作者： Xinyuan Liua,Dingwu He a,Liuqing Pei b,Suming Zhanga a school of Electronics Engineering and Computer Science,Peking university,Beijing 100871,{2. b College of Information Science and Engineering,Beijing Normal university,Beijing 100875,{2. [a]school of Electronics Engineering and Computer Science Peking University Beijing 100871 China [b]College of Information Science and Engineering Beijing Normal University Beijing 100875 China

The time-frequency characteristics of the spectral density of non-stationary signals(NSS) in the neighborhood of an instant time point can be determined using the evolutionary spectral *** experimental rabbit model involving ligation of the left anterior descending coronary artery to simulate the physiology of early phase myocardial ischemia(EPMI) has been previously ***,EPMI derived from left coronary artery stenosis is the main symptom of coronary heart diseases including acute myocardial ***,we propose a new algorithm for estimating the evolutionary spectral density functions,which is an effective approach to determine the instantaneous frequency spectra(IFS) of NSS under the uncertainty principle in the time-frequency *** localization singularity information in the data recorded from a living system could be detected by means of the ***(ECG) data recorded from experimental rabbits were analyzed with the new *** showed that the Q’s value of the evolutionary spectral quality number of the QRS-complex data was the characteristic parameter of ECG,and there was a matched connection between the time-frequency characteristics of QRS-complex data and the myocardial ischemia symptoms of the *** results provide valuable information regarding features of the EPMI for use in clinical diagnoses.

关键词： Non-stationary signals Electrocardiogram(ECG) Evolutionary spectrum Instantaneous frequency spectrum(IFS) Myocardial ischemia

Spatial Variability of Soil Saturated Hydraulic Conductivity in a Small Watershed of Loess Hilly Region,china

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Forestry Science and technology 2008年第2期7卷 41-48页

作者： SHI Hui1 WANG Feng2.1. school of Environmental and Municipal Engineering, Xi’an university of Architecture and {2. Xi’an 710055, P. R. china 2. Sichuan Forestry Institute of Surveying and Planning, Chengdu 610081, P. R. china

Saturated hydraulic conductivity (Ks) is an important soil hydraulic parameter for charactering the rate of water flow across the soils and is mainly related to its high spatial variability. In a small watershed with the area of 0.2. km2.in the Loess Plateau, Ks of 197 soil samples under different vegetations and landforms were measured. Ks had a moderate variability for total samples. The forestland had high Ks with low coefficient of variation (CV), but the grassland in the watershed bottom had low Ks with big CV. Ks had moderate correlation in space distribution and combined both structural and random factors. At the N-S and E-W directions of watershed being parallel and normal to the stream valley, Ks had relatively weak correlation, indicating that the random factor was the dominate reason causing spatial variance. At the NE-SW and SE-NW directions, Ks had relatively strong correlation due to structural factors such as geomorphology and vegetation distribution patterns. Kriging optimal estimation method was used to produce Ks contour map. The Kriging standard deviation (SD) was the lowest near the sampling points, and increased along with the distance to sampling points. In the Loess Plateau region, soil texture is relatively even, and the vegetation distribution pattern was the key factor affecting spatial variability of Ks.

关键词： saturated hydraulic conductivity (Ks) spatial variability vegetation distribution pattern

Inhibitory effect of Ca2. on in vivo gene transfer by electroporation

在线全文

学校读者我要写书评

暂无评论

Acta Pharmacologica Sinica 2006年第3期27卷 307-310页

作者： Yong-gang ZHAO~2.Hui-li LU~2.Jin-liang PENG~2.Yu-hong XU~(2.3,4) ~2.0} of Life Science and Biotechnology and ~3school of Pharmacy,Shanghai Jiaotong university,Shanghai 2.02.0,china schoolofLifeScienceandBiotechnologyandShanghai2.02.0 China schoolofPharmacy ShanghaiJiaotongUniversityShanghai200240China

Aim:To investigate the specific effects of Ca2.on transgene expression duringelectroporation-mediated gene transfer in ***:Skeletal muscle andskin were subjected to in vivo electroporation with a luciferase reporter plasmid,with or without Ca2.and various other ***:For in vivo electroporation,the presence of just 10 mmol/L Ca2.in the DNA solution drastically reduced theresulting transgene expression,to less than 5% of control *** Ca2.,notother ions,caused inhibition,and the effect was not tissue ***,even when Ca2.ions were delivered by electroporation before orafter DNA administration,similar effects were still ***:Theinhibitory effect of Ca2.on in vivo gene transfer by electroporation is specific,ie,the inhibitory effect may be related to the cell membrane properties afterelectroporation and the subsequent resealing event.

关键词： gene therapy electroporation gene transfer calcium ion

The Development and Application of Modern Logistic Information technology

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The Development and Application of Modern Logistic Informati...

Statistical analysis on adaptive evolution of SQUA genes in angiosperms

工程和商业管理国际学术会议

作者： Mu Jing 1 Wan Zhicheng 2.school of Economics and Management Tianjin university of Science & {2. TUST Tianjin china

Logistics informatization is the footstone and core in the development of modern logistics, and it’s a potential trend to combine the high-technology, which takes information technology as the representative, with traditional logistics enterprises. Therefore, in the development of the logistics industry today, we should be fully aware of the enormous influence that the important logistics information technologies exerted.

关键词： Modern Logistic Information technology Logistic Label technology Logistic Location technology EDI ITS

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第1期 94-97页

作者： CHEN Yongyan 1,2. ZHONG Yang 3*, TIAN Bo 1, YANG Ji 4 and LI Dezhu 1*(1. Laboratory of Plant Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of sciences, Kunming 6502.4, china 2. College of Bioengineering, Dalian {2., Dalian 11662., china 3. Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering, school of Life Science, Fudan {2., Shanghai 2.0433, china 4. College of Life sciences, Peking {2., Beijing 100871, china) Laboratory of Plant Biodiversity and Biogeography，Kunming Institute of Botany，Chinese Academy of sciences，Kunming 6502.4 China College of Bioengineering，Dalian university，Dalian 11662.，china Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering，school of Life Science，Fudan university，Shanghai 2.0433，{2. Laboratory of Plant Biodiversity and Biogeography，Kunming Institute of Botany，Chinese Academy of sciences，Kunming 6502.4 China College of Life sciences，Peking university，Beijing 100871，{2.

SQUAMOSA (SQUA) subfamily includes important perianth identity genes of MADS-box gene family. SQUA genes of Dendrocalamus latiflorus were sequenced, and phylogenetic form on SQUA genes in angiosperms was analyzed. Relative rate and adaptive evolution after SQUA gene duplication in recent common ancestor of monocots and eudicots were analyzed using the methods of relative rate test, statistic on synonymous and non-synonymous coden substitution sites and likelihood rate test. The results show that both of relative rate and synonymous and non-synonymous coden substitution in eudicot clade are significantly higher than those in monocot clade, and the value of d N/d S uncovered possible positive selective pressure in eudicot clade.

关键词： angiosperms Dendrocalamus latiflorus SQUA gene relative rate test likelihood rate test adaptive evolution.

基于误比特率计算的Ad Hoc传感器网络连接性分析

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

铁道学报 2005年第1期27卷 75-78页

作者：朱西平方旭明靳蕃西南交通大学计算机与通信工程学院

目前对于AdHoc网的研究主要集中在仿真与分析上,而缺乏理论上的计算与分析。本文在基于网络节点均匀分布的情况下,对AdHoc传感器网络的连接性进行了理论计算,在无干扰和有干扰环境下分别得出了通信路由中端到端平均误比特率(BER)和平均... 详细信息

目前对于AdHoc网的研究主要集中在仿真与分析上,而缺乏理论上的计算与分析。本文在基于网络节点均匀分布的情况下,对AdHoc传感器网络的连接性进行了理论计算,在无干扰和有干扰环境下分别得出了通信路由中端到端平均误比特率(BER)和平均连接跳数(Hop)的精确表达式。结果表明:网络中节点分布密度存在门限值;如果低于此门限值,则网络中节点之间不能进行通信。

关键词：移动通信 ad hoc网络传感器网络连接性误比特率

BATE curve in assessment of clinical utility of predictive biomarkers

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2012年第8期55卷 1529-1552页

作者： ZHOU XiaoHua 1,2.3,& MA YunBei 4,5 1 Northwest HSR&D Center of Excellence,VA Puget Sound Health Care System,Seattle,WA 98198,USA 2.Department of Biostatistics,university of Washington,Seattle,WA 98198,USA 3 Beijing International Center for Mathematical Research,Peking university,Beijing 100871,{2. 4 Department of Operations Research and Financial Engineering,Princeton university,Princeton,NJ 08540,USA 5 school of Statisitcs,Southwest university of Finance and Economics,Chengdu 611130,{2. 1. Northwest HSR&D Center of Excellence VA Puget Sound Health Care System Seattle WA 98198 USA2. Department of Biostatistics University of Washington Seattle WA 98198 USA3. Beijing International Center for Mathematical Research Peking University Beijing 100871 China4. Department of Operations Research and Financial Engineering Princeton University Princeton NJ 08540 USA5. School of Statisitcs Southwest University of Finance and Economics Chengdu 611130 China

In this paper, for time-to-event data, we propose a new statistical framework for casual inference in evaluating clinical utility of predictive biomarkers and in selecting an optimal treatment for a particular patient. This new casual framework is based on a new concept, called Biomarker Adjusted Treatment Effect （BATE） curve. The BATE curve can be used for assessing clinical utility of a predictive biomarker, for designing a subsequent confirmation trial, and for guiding clinical practice. We then propose semi-p^rametric methods for estimating the BATE curves of biomarkers and establish asymptotic results of the proposed estimators for the BATE curves. We also conduct extensive simulation studies to evaluate finite-sample properties of the proposed estimation methods. Finally, we illustrate the application of the proposed method in a real-world data set.

关键词： predictive biomarker cutoff points interaction BATE curve time-to-event outcome

Experimental Investigation and Numerical Simulation of the Grain Size Evolution during Isothermal Forging of a TC6 Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 2005年第2期21卷 155-160页

作者： Miaoquan LI, Shankun XUE, Aiming XIONG and Shenghui CHEN State Key Laboratory of Solidification Processing, school of Materials Science and Engineering, Northwestern Polytechnical university, Xi’an 710072.{2. State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern PolytechnicalUniversity Xi'an 710072 China

Hot compression was conducted at a Thermecmaster-Z simulator, at deformation temperatures of 800-1040℃, with strain rates of 0.001-50 s-1 and height reduction of 50%. Grain size of the prior α phase was measured with a Leica LABOR-LUX12.FS/ST microscope to which QUANTIMET 500 software for image analysis for quantitative metallography was linked. According to the present experimental data, a constitutive relationship for a TC6 alloy and a model for grain size of the prior a phase were established based on the Arrhenius' equation and the Yada's equation, respectively. By finite element (FE) simulation, deformation distribution was determined for isothermal forging of a TC6 aerofoil blade at temperatures of 860-940℃ and hammer velocities of 9-3000.0 mm/min. Meanwhile, the grain size of the prior α phase is simulated during isothermal forging of the TC6 aerofoil blade, by combining FE outputs with the present grain size model. The present results illustrate the grain size and its distribution in the prior α phase during the isothermal forging of the TC6 aerofoil blade. The simulated results show that the height reduction, deformation temperature, and hammer velocity have significant effects on distribution of the equivalent strain and the grain size of the prior α phase.

关键词： Titanium alloy Isothermal forging Grain size Model Finite element (FE) simulation

晶格各向同性应变对闪锌矿结构CrS和CrSe的半金属性和磁性的影响

在线全文

学校读者我要写书评

暂无评论

物理学报 2011年第12期60卷 460-467页

作者：姚仲瑜傅军龚少华张月胜姚凯伦海南师范大学物理与电子工程学院海口571158 华中科技大学物理学院武汉430047

采用基于密度泛函理论的全势能线性缀加平面波方法,对闪锌矿结构CrS和CrSe的电子结构进行自旋极化计算.闪锌矿相CrS和CrSe处于平衡晶格常数时为半金属性,它们的分子自旋磁矩都为4.00μB.使晶体相对于平衡晶格在±10%的范围内发生各向同... 详细信息

采用基于密度泛函理论的全势能线性缀加平面波方法,对闪锌矿结构CrS和CrSe的电子结构进行自旋极化计算.闪锌矿相CrS和CrSe处于平衡晶格常数时为半金属性,它们的分子自旋磁矩都为4.00μB.使晶体相对于平衡晶格在±10%的范围内发生各向同性应变,并计算闪锌矿相CrS和CrSe的电子结构.计算结果表明,闪锌矿相CrS和CrSe相对于平衡晶格的各向同性应变分别为-1%—10%和-4%—10%时仍然保持半金属铁磁性,并且分子总磁矩都稳定于4.00μB.

关键词：各向同性应变电子结构半金属性磁性