期刊文献+
共找到6,311篇文章
< 1 2 250 >
每页显示 20 50 100
Study on Chaotic Characteristics of the Friction Process between High Hardness Alloy Steel and Cemented Carbide under C60 Nanoparticle Fluid Lubrication
1
作者 Jingshan Huang Bin Yao +1 位作者 Qixin Lan Zhirong Pan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第1期525-550,共26页
Friction and wear phenomenon is a complex nonlinear system,and it is also a significant problem in the process of metal cutting.In order to systematically analyze the friction and wear process of tool material-workpie... Friction and wear phenomenon is a complex nonlinear system,and it is also a significant problem in the process of metal cutting.In order to systematically analyze the friction and wear process of tool material-workpiece material friction pair in the cutting process of high hardness alloy steel under different lubrication conditions,the chaotic characteristics of friction process between high hardness alloy steel and cemented carbide under the lubrication C60 nano-particles fluid are studied based on the chaos theory.Firstly,the friction and wear experiments of the friction pair between high hardness alloy steel and cemented carbide tool are carried out based on the ring-block friction and wear tester,and the results of friction force signal in time domain and wear width are obtained.Then,the friction signals in time domain are processed and transformed based on phase space reconstruction and recurrence plot theory,and the recurrence plots of different experimental groups under different lubrication conditions are generated.The evolution law of recurrence plot is further observed and studied,and the recursive quantitative index is analyzed.Finally,the cutting experiments of tool wear are carried out.The results show that the proposed method can intuitively and accurately reveal the wear evolution process and the wear feature identification law of the tool material-high hardness alloy steel pair under different lubrication conditions.Meanwhile,it is found that when the concentration of C60 nanoparticles is 200∼300 ppm,the stability of the friction pair system is best.The proposed method can provide a strategy for wear prediction in cutting process,and provide a theoretical basis and technical support for antifriction lubrication methods in practical cutting applications. 展开更多
关键词 C60 nanoparticles recurrence plot FRICTION STABILITY
下载PDF
Community Structure and Diversity Distributions of Small Mammals in Different Sample Plots in the Eastern Part of Wuling Mountains 被引量:13
2
作者 刘井元 杜红 +3 位作者 田耕百 余品红 王身文 彭红 《Zoological Research》 CAS CSCD 北大核心 2008年第6期637-645,共9页
Five years' (2000-2004) continuous study has been carried out on small mammals such as rodents in seven different sample plots, at three different altitudes and in six different ecological environment types in the ... Five years' (2000-2004) continuous study has been carried out on small mammals such as rodents in seven different sample plots, at three different altitudes and in six different ecological environment types in the eastern part of the Wuling Mountains, south bank of the Three Gorges of Yangtze River in Hubei. A total of 29 297 rat clamps/times were placed and 2271 small mammals such as rodents were captured, and 26 small mammals were captured by other means. All the small mammals captured belonged to 8 families 19 genera and 24 species, of which rodentia accounted for 70.83% and insectivora 29.17%. Through analysis of the data, the results showed that: 1 ) although the species richness had a trend of increasing along different sample plots as altitude increased from south to north, quite a few species showed a wide habitat range in a vertical distribution ( 15 species were dispersed over three zones and two species over two zones) , indicating a strong adaptability of small mammals such as rOdents at lower altitudes in most areas and comparatively less vertical span of entire mountains; 2) whether in seven different sample plots or six different ecological types, Apodemus agrarius and Rattus norvegicus were dominant species below 1200m, and Anourosorex squamipes, Niviventer confucianus and Apodemus draco were dominant above altitudes of 1300m, however, in quantity they were short of identical regularity, meaning they did not increase as the altitude did, or decrease as the ecological areas changed; 3)the density in winter was obviously greater than that in spring, and the distribution showed an increasing trend along with altitude, but the density in different sample plots was short of identical regularity, showing changes in different seasons and altitude grades had an important impact on small mammals such as rodents; 4) in species diversity and evenness index, there were obvious changes between the seven different sample plots, probably caused by frequent human interference in this area. Comparatively speaking, there was less human interference at high altitudes where vegetation was rich and had a high diversity and evenness index, and the boundary effect and community stability were obvious. Most ecological types have been seriously interfered with due to excessive assart at low altitudes with singular vegetation and low diversity and evenness index and poor community stability, showing an ecosystem with poor anti-reversion. If human interference can be reduced in those communities at high altitudes with low diversity and evenness index, the biological diversity in the communities will gradually recover to similar levels of other ecological areas. 展开更多
关键词 Small mammals Community structure Species diversity Sample plots Eastern part of Wuling Mountains
下载PDF
Excavating and Expressing the Individuality Culture in the Environmental Landscape Design of Residential Plot——Taking the Environmental Landscape Section of ‘Miaojiang·Yujinyuan’ Residential Plot in Taijiang County of Guizhou Province as an Example
3
作者 王志泰 包玉 张静 《Journal of Landscape Research》 2009年第6期1-4,共4页
Local culture resources were excavated and expressed in environmental landscape section of ‘Miaojiang ·Yujinyuan’ residential plot in Taijiang County of Guizhou Province, with lusheng, Bronze drum and national ... Local culture resources were excavated and expressed in environmental landscape section of ‘Miaojiang ·Yujinyuan’ residential plot in Taijiang County of Guizhou Province, with lusheng, Bronze drum and national architecture as design elements. Making environmental landscape of residential plot, where the minority nationality lived in, possess culture agreement and emotion arrangement. 展开更多
关键词 RESIDENTIAL plot Environmental LANDSCAPE INDIVIDUALITY CULTURE Expression
下载PDF
The Alienated Plot in The End of the Road
4
作者 王丽娜 《海外英语》 2014年第19期188-190,共3页
The End of the Road is John Barth's second novel, and it is the first novel that brought abortion to the focus of public attention, which proves to be a huge success. This paper intends to study the alienation in ... The End of the Road is John Barth's second novel, and it is the first novel that brought abortion to the focus of public attention, which proves to be a huge success. This paper intends to study the alienation in The End of the Road based on the alienation as a literary style and the alienation embodied in the literary context. Through the analysis of the alienated plot, the paper aims to emphasize the internal cause for the end of the different character's road. 展开更多
关键词 the END of the ROAD ALIENATION the alienated plot
下载PDF
“Free plot” Set in Katherine Mansfield’s Garden Party
5
作者 张小未 《科教文汇》 2006年第11期172-173,共2页
关键词 Katherine MANSFIELD GARDEN PARTY Free plot
下载PDF
Fischer Plots of Wumishan Cyclothems,Precambrian Records of Third-OrderSea-Level Changes 被引量:11
6
作者 Mei Mingxiang Faculty of Earth Sciences and Mineral Resources, China University of Geosciences, Beijing 100083 Ma Yongsheng China Petrochemical Corporation (SINOPEC), Beijing 100029 Zhou Hongrui Du Benming Luo Zhiqing Guo Qingyin Faculty of Earth Sc 《Journal of China University of Geosciences》 SCIE CSCD 2001年第1期1-10,共10页
The Mesoproterozoic Wumishan Formation ((1310 ± 20 ) Ma - (l 207 ± 10) Ma) in Jixian, Tianjin represents a succession of 3 300 meter thick carbonate strata where are the best developed stromatolite biostrom... The Mesoproterozoic Wumishan Formation ((1310 ± 20 ) Ma - (l 207 ± 10) Ma) in Jixian, Tianjin represents a succession of 3 300 meter thick carbonate strata where are the best developed stromatolite biostromes and thrombolite bioherms. These biostromes and bioherms, together with tidal-flat dolomites and muddy dolostones, form Wumishan cyclothems with approximately symmetrical faciessuccession fabrics, which belong to carbonate meter-scale cyclic sequences of peritidal type. These cyclothems are overlain by lagoon dolomitic mudstones and shales and by frequently developed paleosol layers, indicating that the boundary of Wumishan cyclothems is marked by an instantaneously-exposed punctuated surface. Viewed form the regularly vertical stacking patterns of Wumishan cyclothems in long-term sequences, 26 third-order sequences may be discerned in Wumishan Formation. These thirdorder sequences may also be incorporated into six second-order sequences. In order to study the variation range of third-order sea-level changes and the formation period of third-order sequence, 626 cyclothems are discerned in the middle and upper parts of Wumishan Formation where the outcrops are well developed. In terms of the total thickness and the formation period of Mesoproterozoic Wumishan Formation, the crust subsidence rate in the sedimentary period of Wumishan Formation is supposed to be 3 meters at each interval of 100 thousands years. Based on this assumption, Fischer plot might be designed to simulate the third-order sea-level changing pattern. 展开更多
关键词 Wumisban cyclothems Fischer plots MESOPROTEROZOIC Jixian of Tianjin.
下载PDF
Spatial and temporal analysis of beta diversity in the Barro Colorado Island forest dynamics plot, Panama 被引量:3
7
作者 Pierre Legendre Richard Condit 《Forest Ecosystems》 SCIE CSCD 2019年第1期76-86,共11页
Background: Ecologists are interested in assessing the spatial and temporal variation in ecological surveys repeated over time. This paper compares the 1985 and 2015 surveys of the Barro Colorado Forest Dynamics plot(... Background: Ecologists are interested in assessing the spatial and temporal variation in ecological surveys repeated over time. This paper compares the 1985 and 2015 surveys of the Barro Colorado Forest Dynamics plot(BCI), Panama,divided into 1250(20 m × 20 m) quadrats.Methods, spatial analysis: Total beta diversity was measured as the total variance of the Hellinger-transformed community data throughout the BCI plot. Total beta was partitioned into contributions of individual sites(LCBD indices), which were tested for significance and mapped.Results, spatial analysis: LCBD indices indicated the sites with exceptional community composition. In 1985,they were mostly found in the swamp habitat. In the 2015 survey, none of the swamp quadrats had significant LCBDs.What happened to the tree community in the interval?Methods, temporal analysis: The dissimilarity in community composition in each quadrat was measured between time 1(1985) and time 2(2015). Temporal Beta Indices(TBI) were computed from abundance and presence-absence data and tested for significance. TBI indices can be decomposed into B = species(or abundances-per-species) losses and C = species(or abundances-per-species) gains. B-C plots were produced; they display visually the relative importance of the loss and gain components, through time, across the sites.Results, temporal analysis: In BCI, quadrats with significant TBI indices were found in the swamp area, which is shrinking in importance due to changes to the local climate. A published habitat classification divided the BCI forest plot into six habitat zones. Graphs of the B and C components were produced for each habitat group. Group 4(the swamp) was dominated by species(and abundances-per-species) gains whereas the five other habitat groups were dominated by losses, some groups more than others.Conclusions: We identified the species that had changed the most in abundances in the swamp between T1 and T2.This analysis supported the hypothesis that the swamp is drying out and is invaded by species from the surrounding area. Analysis of the B and C components of temporal beta diversity bring us to the heart of the mechanisms of community change through time: losses(B) and gains(C) of species, losses and gains of individuals of various species. TBI analysis is especially interesting in species-rich communities where we cannot examine the changes in every species individually. 展开更多
关键词 BETA DIVERSITY B-C plotS BCI forest dynamics plot Space-time analysis Temporal BETA DIVERSITY
下载PDF
Comparison study of typical algorithms for reconstructing time series from the recurrence plot of dynamical systems 被引量:1
8
作者 刘杰 石书婷 赵军产 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第1期131-137,共7页
The three most widely used methods for reconstructing the underlying time series via the recurrence plots (RPs) of a dynamical system are compared with each other in this paper. We aim to reconstruct a toy series, a... The three most widely used methods for reconstructing the underlying time series via the recurrence plots (RPs) of a dynamical system are compared with each other in this paper. We aim to reconstruct a toy series, a periodical series, a random series, and a chaotic series to compare the effectiveness of the most widely used typical methods in terms of signal correlation analysis. The application of the most effective algorithm to the typical chaotic Lorenz system verifies the correctness of such an effective algorithm. It is verified that, based on the unthresholded RPs, one can reconstruct the original attractor by choosing different RP thresholds based on the Hirata algorithm. It is shown that, in real applications, it is possible to reconstruct the underlying dynamics by using quite little information from observations of real dynamical systems. Moreover, rules of the threshold chosen in the algorithm are also suggested. 展开更多
关键词 recurrence plot chaotic system time series analysis correlation analysis
下载PDF
Locating the cocktail and scaling-relation breaking effects of high-entropy alloy catalysts on the electrocatalytic volcano plot 被引量:4
9
作者 Junxiang Chen Yaxin Ji 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第11期2889-2897,共9页
High entropy alloys(HEAs)have been the star materials in electrocatalysis research in recent years.One of their key features is the greatly increased multiplicity of active sites compared to conventional catalytic mat... High entropy alloys(HEAs)have been the star materials in electrocatalysis research in recent years.One of their key features is the greatly increased multiplicity of active sites compared to conventional catalytic materials.This increased multiplicity stimulates a cocktail effect and a scaling-relation breaking effect,and results in improved activity.However,the multiplicity of active sites in HEAs also poses new problems for mechanistic studies.One apparent problem is the inapplicability to HEA catalysts of the currently most popular mechanistic study method,which uses the electrocatalytic theoretical framework(ETF)based on the computational hydrogen electrode(CHE).The ETF uses a single adsorption energy to represent the catalyst,i.e.,a catalyst is represented by a'point'in the volcanic relationship.It naturally does not involve the multiplicity of active sites of a catalyst,and hence loses brevity in expressing the cocktail effect and scaling-relation breaking effect in HEA catalysis.This paper attempts to solve this inapplicability.Based on the fact that the adsorption energy distribution of HEAs is close to a normal distribution,the mean and variance of the adsorption energy distribution are introduced as descriptors of the ETF,replacing the original single adsorption energy.A quantitative relationship between the variance and the cocktail and scaling-relation braking effects is established.We believe the method described in this work will make the ETF more effective in mechanistic studies of HEA electrocatalysis. 展开更多
关键词 High-entropy alloy Electrocatalysis Volcano plot Cocktail effect Scaling-relation breaking effect Adsorption energy distribution
下载PDF
Airborne Acoustic Transmission and Terrain Topography at SAINTGITS Amphitheatre:An Analysis of Outdoor Auditory Perception and Comparison of Contour Plots 被引量:1
10
作者 Jacob Thottathil Varghese Sajan Thomas +2 位作者 Joselin Herbert Chacko Preno Koshy Arjun Venugopal 《Sound & Vibration》 EI 2022年第3期255-274,共20页
The arrangement of natural and physical features on the earth’s surface are a few among the countless items that govern the airborne acoustic transmission at boundary layers.In particular,if the acoustic waves are at... The arrangement of natural and physical features on the earth’s surface are a few among the countless items that govern the airborne acoustic transmission at boundary layers.In particular,if the acoustic waves are attributes of live concerts at open-air theatres,without losing the sheen and quality,the audience should certainly receive the unbroken depth of the performance.Hence,at all times,it is advisable to analyse the auditory receptiveness,particularly in all intended recreational spaces.The current pandemic circumstances and the mandated COVID-19 prevention protocols encourage gatherings in naturally ventilated outdoor regions than confined indoors.This work predicts and quantifies the acoustic experience at the naturally carved amphitheatre at SAINTGITS,an autonomous institution at the down South-West of the Indian Subcontinent.The entire recreational space at SAINTGITS AMPHI was separately modelled as a Base case and Advanced case,and were analysed using the acoustic modelling module of EASE Focus,a renowned simulation freeware,which is in strict adherence with the International standards.The variation in loudness received at the nearest and farthest ends of the amphitheatre was between 67 to 80 dB.Though the Zero frequency SPL(Z-weighting)exhibited the loudness in the range of 81 to 85 dB and could maintain a safer auditory level for any human ear,it was confined to a hemispherical region near the sound source.A vertical beam angle of−4.0°was found to be effective throughout.The procedures and analyses will certainly help the future organizers and stakeholders to effectively plan the resources to reap rich acoustic experience at terrain-centric locales.The surface topography and contours were plotted with another set of freeware,the CADMAPPER and the QUIKGRID,to compare terrain gradient with the known data.Furthermore,this interdisciplinary research exhibits the extensive simulation capability of both EASE Focus and QUIKGRID and demonstrates the modelling versatility and deliverable potential of these freeware to benefit the budding architects and researchers. 展开更多
关键词 Acoustic airborne transmission Sound Pressure Level(SPL) Amphitheatre SAINTGITS contour plot terrain topology safe acoustics
下载PDF
A Plot Story:The Ransom of Red Chief
11
作者 王思宇 《海外英语》 2015年第2期187-188,共2页
The Ransom of Red Chief is a short story written by O·Henry. Some critics regard it as a plot story but some do not. A typical plot story should focus on the plot :using techniques such as flashback or foreshadow... The Ransom of Red Chief is a short story written by O·Henry. Some critics regard it as a plot story but some do not. A typical plot story should focus on the plot :using techniques such as flashback or foreshadowing to unfold the plot and containing exposition, complication, climax, resolution, conclusion to rich the plot. The main characters are presented with internal and external conflicts as well. In this thesis, a detailed analysis will be presented to prove that this story is really a plot story. 展开更多
关键词 the RANSOM of RED CHIEF ANALYSIS a plot STORY
下载PDF
An Analysis of the Plot and Language Style in The Unicorn in the Garden
12
作者 李霞 《海外英语》 2013年第2X期179-180,共2页
James Thurber was an American humorist and cartoonist. He was hailed as the greatest contributor to American humor writing since Mark Twain. Thurber wrote hundreds of essays and short stories, which often featured gen... James Thurber was an American humorist and cartoonist. He was hailed as the greatest contributor to American humor writing since Mark Twain. Thurber wrote hundreds of essays and short stories, which often featured gender battles between dominant women and little men. The Unicorn in the Garden, one of his short stories, is popular with the readers on the strength of the whirling plot and the unique language style, such as black humor, discontinuity and repetition. Meanwhile, the readers can draw inspiration from this short story. 展开更多
关键词 JAMES Thurber the UNICORN in the GARDEN plot langu
下载PDF
IMPROVEMENT OF THE PLOT METHOD OF FATIGUE LIFE PREDICTION FORMULA
13
作者 Liu Yilun Yao Wei(College of Mechanical and Electrical Engineering,Central South University of Technology, Changsha 410083, China) 《Journal of Central South University》 SCIE EI CAS 1998年第1期54-57,共4页
The fatigue life for components can be predicted by the plot method which is easy and convenient in engineering. Based on the usual fatigue life prediction formula, a new formula for estimating the low stress and hig... The fatigue life for components can be predicted by the plot method which is easy and convenient in engineering. Based on the usual fatigue life prediction formula, a new formula for estimating the low stress and high cycle fatigue life is proposed and deduced, which has adopted more accurate SN curve relationship——WeibullSN curve formula. The solution of the new formula is given, too. In addition, an example has been calculated and proved in practice. The results of the new formula and the old one are given and compared. 展开更多
关键词 FATIGUE LIFE PREDICTION the plot METHOD Weibull SN curve
下载PDF
Study of Quantitative Indices to Describe the Poincare Dispersed-dot Plot for Heart States 被引量:1
14
作者 XU Zheng, GE Ji guang, XU Qiu ping Department of Biological Science and Technology Zhejiang University, Hangzhou, 310027, China 《Chinese Journal of Biomedical Engineering(English Edition)》 2000年第4期180-189,共10页
Poincare dispersed dot plot was an important method in studying heart nonlinear state and rate variability(HRV). Based on the shape of Poincare dispersed dot plot, we proposed four quantitative parameters, introduced ... Poincare dispersed dot plot was an important method in studying heart nonlinear state and rate variability(HRV). Based on the shape of Poincare dispersed dot plot, we proposed four quantitative parameters, introduced the method and algorithm how to get them, and tested them with clinical and animal experiment data. The result showed that these four parameters have certain idiosyncrasy with different heart diseases, and the animal experiment result also showed that these parameters were changed remarkably after coronary artery ligation compared with before, which indicated these parameters might be useful for clinical diagnosis. Because the algorithm we used was based only on the shape of the graph, one can apply this algorithm on any other type of graphs like Poincare dispersed dot plot. 展开更多
关键词 HEART rate variability(HRV) POINCARE dispersed dot plot Nonlinear cardiokinetics
下载PDF
Size Determination of Ultramicropores and Small Mesopores Using a Calculation Procedure Based on the Tangents of Comparison Plot
15
作者 邱芹 刘世权 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第3期391-394,共4页
Pore size distribution(PSD) curves of synthesized hollow silica spheres with ultrmicropores and small mesopores were obtained from calculations based on the BJH,KJS,SF,MP,NLDFT models and Prof.Zhu's method.Comparis... Pore size distribution(PSD) curves of synthesized hollow silica spheres with ultrmicropores and small mesopores were obtained from calculations based on the BJH,KJS,SF,MP,NLDFT models and Prof.Zhu's method.Comparisons indicate that Zhu's method not only gives reasonable small mesopore size but also could be further extended to the ultramicropores region for the PSD evaluation. 展开更多
关键词 pore size distribution comparison plot ultramicropores MESOPORES
下载PDF
A Survey of Mycorrhizal Colonization in the 50-ha Korup Forest Dynamic Plot in Cameroon
16
作者 Eneke Esoeyang Tambe Bechem George Bindeh Chuyong Belinda Tengu Fon 《American Journal of Plant Sciences》 2014年第10期1403-1415,共13页
A study was carried out in the 50-ha Korup Forest Dynamic Plot in South West Cameroon, to evaluate the diversity of mycorrhizal associations as well as to determine the effect of habitat types on the type of mycorrhiz... A study was carried out in the 50-ha Korup Forest Dynamic Plot in South West Cameroon, to evaluate the diversity of mycorrhizal associations as well as to determine the effect of habitat types on the type of mycorrhizal association. A total of 781 individual trees belonging to 51 families, 165 genera and 252 tree species, were sampled from the four habitat types found in the plot: low drier, hill slope, ridge top and wetland complexes. In each habitat type, all stems ≤ 1 cm depth at breast height had already been tagged, measured, mapped and identified to the species level. Root samples were collected, cleared, stained and examined microscopically for mycorrhizal type. Of the total number of species sampled, 248 (98.41%) formed mycorrhizal associations with only 4 (1.59%) being non mycorrhizal. For mycorrhizal trees, 232 (93.55%) formed exclusively arbuscular mycorrhiza, 10 (4.03%) formed ectomycorrhiza, while 6 (2.42%) formed both ecto- and arbuscular mycorrhiza. The ridge top harbored the least number (152) of mycorrhizal trees while the low drier area harbored the most number (266) of mycorrhizal trees. Although habitat effect was not significant in influencing mycorrhizal colonization of tree species, some tree species did show aggregated patterns in particular habitats. 展开更多
关键词 Korup FOREST DYNAMIC plot ARBUSCULAR MYCORRHIZA ECTOMYCORRHIZA Cameroon
下载PDF
Sample Plot Change in the Seventh Review of Continuous National Forest Inventory in Zigui County
17
作者 Zhongmei DENG Jiaxuan XIANG +3 位作者 Jun SONG Xueyong QIN Dongwei WANG Lei ZHOU 《Asian Agricultural Research》 2016年第2期61-63,共3页
The following qualitative conclusions of forest resources in Zigui can be drawn by the research on 73 plots and 5 vegetation plots:forest area is increasing; forest growing stock is increasing; the adjustment of fores... The following qualitative conclusions of forest resources in Zigui can be drawn by the research on 73 plots and 5 vegetation plots:forest area is increasing; forest growing stock is increasing; the adjustment of forest category structure is constantly improved; forest quality has been improving; stand structure is optimized continuously; biodiversity has initially appeared. 展开更多
关键词 NATIONAL FOREST INVENTORY the seventh review in Zigui SAMPLE plot CHANGE
下载PDF
Two Probability Plots of the Three-Parameter Lognormal Distribution
18
作者 蒋仁言 《Journal of Donghua University(English Edition)》 EI CAS 2014年第6期757-759,共3页
The two-parameter lognormal distribution is a variant of the normal distribution and the three-parameter lognormal distribution is an extension of the two-parameter lognormal distribution by introducing a location par... The two-parameter lognormal distribution is a variant of the normal distribution and the three-parameter lognormal distribution is an extension of the two-parameter lognormal distribution by introducing a location parameter. The Q-Q plot of the three-parameter lognormal distribution is widely used. To obtain the Q-Q plot one needs to iteratively try different values of the shape parameter and subjectively judge the linearity of the Q-Q plot. In this paper,a mathematical method was proposed to determine the value of the shape parameter so as to simplify the generation of the Q-Q plot. Then a new probability plot was proposed,which was more easily obtained and provided more accurate parameter estimates than the Q-Q plot. These are illustrated by three realworld examples. 展开更多
关键词 three-parameter lognormal distribution probability plot correlation coefficient model selection parameter estimation
下载PDF
Integrated Assessment of Cardiac PET/MRI: Co-Registered PET and MRI Polar Plots by Mutual MR-Based Segmentation of the Left Ventricular Myocardium
19
作者 Felix Nensa Thorsten D. Poeppel +6 位作者 Ercan Tezgah Philipp Heusch Kai Nassenstein Michael Forsting Andreas Bockisch Raimund Erbel Thomas Schlosser 《World Journal of Cardiovascular Diseases》 2017年第4期91-104,共14页
Background: In the present study, we sought to describe a procedure for the creation of co-registered positron emission tomography (PET) and magnetic resonance imaging (MRI) polar plots of cardiac PET/MRI examinations... Background: In the present study, we sought to describe a procedure for the creation of co-registered positron emission tomography (PET) and magnetic resonance imaging (MRI) polar plots of cardiac PET/MRI examinations, validate the resulting plots against available standard methods in patients with myocardial infarction and provide examples that demonstrate the advantage of the novel approach over existing standards. Methods: Co-registered LGE and PET short-axis images were transformed into polar maps based on a radial sampling pattern. LGE was automatically detected using an automated thresholding algorithm (ATA). In 20 PET/MRI examinations in patients with acute myocardial infarction, agreement between manual LGE assessment and the ATA classification was calculated. Also agreement between MRI-segmentation based PET polar plots and standard PET polar plots (created with the Corridor4DM software package) was assessed. Results: No statistically significant difference in infarct sizes between manual and ATA segmentation was found (p = 0.12). Both methods were highly correlated (Pearson’s r = 0.96, p Conclusion: A straightforward software approach for the creation of co-registered PET and MRI polar plots was described and successfully demonstrated in PET/MRI studies of myocardial infarction and inflammation. 展开更多
关键词 CARDIAC PET/MRI Bull’s Eye POLAR plot POLAR Map
下载PDF
Test of Normality of Waist Measurement Data of Young Male and Female Adults based on the Quantile - Quantile Plot
20
作者 F. Z. Okwonu J. N. Igabari 《Journal of Statistical Science and Application》 2017年第3期118-126,共9页
This paper investigates the normality of some real data set obtained from waist measurements of a group of 49 young adults. The quantile - quantile (Q-Q) plot and the analysis of correlation coefficients for the Q-Q... This paper investigates the normality of some real data set obtained from waist measurements of a group of 49 young adults. The quantile - quantile (Q-Q) plot and the analysis of correlation coefficients for the Q-Q plot is used to determine the normality or otherwise of the data set. In this regards, the probabilities of the quantiles were computed, modified and plotted. Thereafter the correlation coefficients for the quantile - quantile plots were obtained. Results indicate that at 0.1 level of significance, the data for young adult males of the sample were not normally distributed, and had a mean value that is within the range of low risk, healthwise, whereas the distribution of the data for young female adults showed reasonable normality, but also with a mean value that is within the range of low risk in terms of health condition. 展开更多
关键词 Correlation coefficient probability plot quantile - quantile plot test of normality waist measurement young adults.
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部