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正畸治疗需要客观评价指标指数的研究进展 被引量:2
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作者 康云龙 郭骏 +2 位作者 吴碧蓉 白丁 乔鞠 《国际口腔医学杂志》 CAS 2008年第S1期314-317,共4页
错畸形包括从个别正常到严重影响口腔功能的错,要评价一个个体是否需要正畸治疗是非常困难的,它不仅取决于个体错畸形严重程度,还受到个体主观愿望的影响。本文对正畸治疗需要的客观评价指标指数的研究进展进行了综述。
关键词 指数 客观评价 正畸治疗需要
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正畸治疗难度、结果、需要指数的有效性研究 被引量:6
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作者 马盛男 邵玶 张苗苗 《中国美容医学》 CAS 2010年第3期392-394,共3页
目的:检验ICON指数在评价治疗难度、结果和改善程度部分的有效性。方法:哈尔滨医科大学口腔医院10位不同职称的正畸医师对100对按条件选取的治疗前后的模型进行治疗难度、结果和改善程度的评价,测量者再用ICON指数计分这100对模型。在... 目的:检验ICON指数在评价治疗难度、结果和改善程度部分的有效性。方法:哈尔滨医科大学口腔医院10位不同职称的正畸医师对100对按条件选取的治疗前后的模型进行治疗难度、结果和改善程度的评价,测量者再用ICON指数计分这100对模型。在一个月后,专家和测量者再重新测量随机选取的其中的40对模型,运用相关性分析,简单kappa检验和加权kappa检验方法来评价各组内和组间的一致性。结果:专家之间在治疗难度方面的一致性较好(k=0.61),结果方面一致性一般(k=0.32),改善程度方面的一致性较差(k=0.18);ICON测量者对治疗前、后模型测量的的可信度分别为k=0.87,k=0.82。专家组与ICON测量者间难度部分(k=0.67)的一致性为较好,结果部分(k=0.23)的一致性为一般,改善程度部分的一致性为中度(k=0.48)。结论:ICON指数的难度和治疗结果部分是有效的,而在改善程度部分由于专家组间的一致性不好,需进一步被检验。 展开更多
关键词 正畸治疗难度、结果、需要指数 指数 有效性 错畸形
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正畸指数应用研究进展 被引量:4
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作者 黄敏 张晓蓉 《中国实用口腔科杂志》 CAS 2008年第9期558-560,共3页
错畸形会给患者带来诸多不良影响,如牙颌颜面不美观、牙周状况受损、咀嚼功能障碍以及心理社会压力等。随着人们生活水平的提高及口腔知识的普及,越来越多的错畸形患者开始选择正畸治疗来改善自身错状况,以期提高生活质量。
关键词 正畸指数 错畸形
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山西省植被指数时空变化特征及其对气候变化的响应 被引量:6
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作者 李丽红 贾琇明 刘珺 《湖北农业科学》 2015年第17期4143-4147,共5页
基于2001-2013年山西省中分辨率成像光谱仪(MODIS)植被指数产品(MOD 13Q1)和气象数据(气温、降水量),利用斜率分析法、相关系数分析法等方法 ,研究近13年来植被指数(增强型植被指数EVI、归一化植被指数NDVI)的时空变化特征,以及植被覆... 基于2001-2013年山西省中分辨率成像光谱仪(MODIS)植被指数产品(MOD 13Q1)和气象数据(气温、降水量),利用斜率分析法、相关系数分析法等方法 ,研究近13年来植被指数(增强型植被指数EVI、归一化植被指数NDVI)的时空变化特征,以及植被覆盖变化对气候变化的响应。结果表明,年际变化方面,整体EVI和NDVI年均值显著增加,每个月均值也呈递增趋势,其中7月份的年际增长变化最为显著(EVI、NDVI的线性增长率分别为0.003 8和0.005 7);空间分布上,植被覆盖较茂密的地区主要分布在山区一带,植被稀疏区主要位于盆地附近;植被指数与年均降水量呈显著正相关,与年均气温整体上呈负相关,显著性并不明显,表明植被覆盖受降水变化影响较大,对其变化响应较强,受温度变化影响较小,呈弱响应关系。 展开更多
关键词 山西省 气温 降水量
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Ecological environmental quality evaluation and driving factor analysis of the Lijiang River Basin,based on Google Earth Engine
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作者 WEI Xi YANG Dazhi +2 位作者 CAI Xiangwen SHAO Ya TANG Xiangling 《中国生态农业学报(中英文)》 CAS CSCD 北大核心 2024年第9期1592-1608,共17页
For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological... For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological index(RSEI)was calculated for the Lijiang River Basin in Guangxi Zhuang Autonomous Region for 1991,2001,2011,and 2021.Spatial autocorrelation analysis was employed to investigate spatiotemporal variations in the ecological environmental quality of the Lijiang River Basin.Furthermore,geographic detectors were used to quantitatively analyze influencing factors and their interaction effects on ecological environmental quality.The results verified that:1)From 1991 to 2021,the ecological environmental quality of the Lijiang River Basin demonstrated significant improvement.The area with good and excellent ecological environmental quality in proportion increased by 19.69%(3406.57 km^(2)),while the area with fair and poor ecological environmental quality in proportion decreased by 10.76%(1860.36 km^(2)).2)Spatially,the ecological environmental quality of the Lijiang River Basin exhibited a pattern of low quality in the central region and high quality in the periphery.Specifically,poor ecological environmental quality characterized the Guilin urban area,Pingle County,and Lingchuan County.3)From 1991 to 2021,a significant positive spatial correlation was observed in ecological environmental quality of the Lijiang River Basin.Areas with high-high agglomeration were predominantly forests and grasslands,indicating good ecological environmental quality,whereas areas with low-low agglomeration were dominated by cultivated land and construction land,indicating poor ecological environmental quality.4)Annual average precipitation and temperature exerted the most significant influence on the ecological environmental quality of the basin,and their interactions with other factors had the great influence.This study aimed to enhance understanding of the evolution of the ecological environment in the Lijiang River Basin of Guangxi Zhuang Autonomous Region and provide scientific guidance for decision-making and management related to ecology in the region. 展开更多
关键词 Ecological environmental quality Remote sensing ecological index Driving factor Google Earth Engine Lijiang River Basin
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The influences of canopy temperature measuring on the derived crop water stress index
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作者 WANG Hongxi LI Fei +4 位作者 SHEN Hongtao LI Mengyu YIN Gongchao FANG Qin SHAO Liwei 《中国生态农业学报(中英文)》 CAS CSCD 北大核心 2024年第9期1503-1519,共17页
Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the... Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management. 展开更多
关键词 Canopy temperature Measuring time Measuring height and direction Crop water stress index
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医患双方对错畸形认识的一致性研究
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作者 杨斌 范永斌 《口腔医学》 CAS 2011年第9期570-571,共2页
目的分析医患双方对错畸形程度认识的差异。方法选择162例患者,按照主动就诊和被动就诊分组,采用正畸治疗需要指数,医患双方同时对模型进行评分,并对结果的一致性进行分析。结果医患双方对畸形程度的认识存在明显差异,主动就诊组两部... 目的分析医患双方对错畸形程度认识的差异。方法选择162例患者,按照主动就诊和被动就诊分组,采用正畸治疗需要指数,医患双方同时对模型进行评分,并对结果的一致性进行分析。结果医患双方对畸形程度的认识存在明显差异,主动就诊组两部分都有明显差异,被动就诊组主要表现在功能方面。结论医患双方对畸形程度的认识存在一定差距。 展开更多
关键词 指数 错畸形
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FINITE RANGE SET WITH TRUNCATED MULTIPLICITY FOR MEROMORPHIC FUNCTIONS ON SOME COMPLEX DISC
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作者 WANG Yu-ting CAO Hong-zhe 《数学杂志》 2024年第5期383-396,共14页
In this paper,we consider the truncated multiplicity finite range set problem of meromorphic functions on some complex disc.By using the value distribution theory of meromorphic functions,we establish a second main th... In this paper,we consider the truncated multiplicity finite range set problem of meromorphic functions on some complex disc.By using the value distribution theory of meromorphic functions,we establish a second main theorem for meromorphic functions with finite growth index which share meromorphic functions(may not be small functions).As its application,we also extend the result of a finite range set with truncated multiplicity. 展开更多
关键词 meromorphic functions finite growth index complex disc finite range set trun-cated multiplicity
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Research on Thermodynamic Properties of Polybrominated Diphenylamine by Neural Network 被引量:19
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作者 堵锡华 庄文昌 +1 位作者 史小琴 冯长君 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2015年第1期59-64,I0001,I0002,共8页
Based on the location of bromine substituents and conjugation matrix, a new substituent po- sition index ~X not only was defined, but also molecular shape indexes Km and electronega- tivity distance vectors Mm of diph... Based on the location of bromine substituents and conjugation matrix, a new substituent po- sition index ~X not only was defined, but also molecular shape indexes Km and electronega- tivity distance vectors Mm of diphenylamine and 209 kinds of polybrominated diphenylamine (PBDPA) molecules were calculated. Then the quantitative structure-property relationships (QSPR) among the thermodynamic properties of 210 organic pollutants and 0X, K3, M29, M36 were founded by Leaps-and-Bounds regression. Using the four structural parameters as input neurons of the artificial neural network, three satisfactory QSPR models with network structures of 4:21:1, 4:24:1, and 4:24:1 respectively, were achieved by the back-propagation algorithm. The total correlation coefficients R were 0.9999, 0.9997, and 0.9995 respectively and the standard errors S were 1.036, 1.469, and 1.510 respectively. The relative mean deviation between the predicted value and the experimental value of Sθ, AfHe and △fGθ- were 0.11%, 0.34% and 0.24% respectively, which indicated that the QSPR models had good stability and superior predictive ability. The results showed that there were good nonlinear correlations between the thermodynamic properties of PBDPAs and the four structural pa- rameters. Thus, it was concluded that the ANN models established by the new substituent position index were fully applicable to predict properties of PBDPAs. 展开更多
关键词 Polybrominated diphenylamine Neural networks Molecular shape index Elec-tronegativity distance vector Substituent position index Thermodynamic properties
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Ecological risk assessment of heavy metals in sediments of Xiawan Port based on modified potential ecological risk index 被引量:40
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作者 祝慧娜 袁兴中 +7 位作者 曾光明 蒋敏 梁婕 张长 尹娟 黄华军 刘智峰 江洪炜 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第6期1470-1477,共8页
Modified potential ecological risk index (MRI) was proposed based on the potential ecological risk index (RI) and risk assessment code (RAC) by modifying an index. The modified index was relevant to the chemical... Modified potential ecological risk index (MRI) was proposed based on the potential ecological risk index (RI) and risk assessment code (RAC) by modifying an index. The modified index was relevant to the chemical speciation of heavy metals. Xiawan Port, a typical region contaminated by industrial production, was selected as a case study area. The total concentrations and chemical speciation of heavy metals in sediments of Xiawan Port were analyzed. The experimental data indicate that Xiawan Port is seriously polluted by heavy metals, especially by Cd. The risks of heavy metals are evaluated by RI, RAC and MRI, respectively. The resluts of MRI show that the risks of heavy metals are in the decreasing order of Cd〉Pb〉Cu〉Zn. Comparison of results by different methods reveals that MRI integrates the characters of RI and RAC. MRI is recognized to be useful for risk managemnt of heavy metals in sediments. 展开更多
关键词 heavy metals chemical speciation modified potential ecological risk index SEDIMENTS Xiawan Port
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Environmental availability and ecological risk assessment of heavy metals in zinc leaching residue 被引量:26
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作者 闵小波 谢先德 +3 位作者 柴立元 梁彦杰 李密 柯勇 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期208-218,共11页
Four different methods,namely mineralogical analysis,three-stage BCR sequential extraction procedure,dynamic leaching test and Hakanson Potential Ecological Risk Index Method were used to access the environmental acti... Four different methods,namely mineralogical analysis,three-stage BCR sequential extraction procedure,dynamic leaching test and Hakanson Potential Ecological Risk Index Method were used to access the environmental activity and potential ecological risks of heavy metals in zinc leaching residue.The results demonstrate that the environmental activity of heavy metals declines in the following order:CdZnCuAsPb.Potential ecological risk indices for single heavy metal are CdZnCuAsPb.Cd has serious potential ecological risk to the ecological environment and contributes most to the potential toxicity response indices for various heavy metals in the residue. 展开更多
关键词 heavy metals BCR sequential extraction environmental availability leaching toxicity dynamic leaching potential ecological risk index method zinc leaching residue
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Genetic Diversity in Cultivated Groundnut Based on SSR Markers 被引量:6
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作者 唐荣华 高国庆 +7 位作者 贺梁琼 韩柱强 单世华 钟瑞春 周翠球 蒋菁 李杨瑞 庄伟建 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2007年第5期449-459,共11页
Peanut (Arachis hypogaea L.) is an important source crop for edible oil and protein. It is important to identify the genetic diversity of peanut genetic resources for cultivar development and evaluation of peanut ac... Peanut (Arachis hypogaea L.) is an important source crop for edible oil and protein. It is important to identify the genetic diversity of peanut genetic resources for cultivar development and evaluation of peanut accessions. Thirty-four SSR markers were used to assess the genetic variation of four sets of twenty-four accessions each from the four botanical varieties of the cultivated peanut. Among the tested accessions, ten to sixteen pairs of SSR primers showed polymorphisms. The maximum differentiation index, which was defined as the degree of genetic differentiation, was as high as 0.992 in the tested accessions. Each accession could be discriminated by a specific set of polymorphic SSR primers, and the intra-variety genetic distance was determined among accessions, with an average of 0.59 in var. fastigiata, 0.46 in var. hypogaea, 0.38 in var. vulgaris, and 0.17 in var. hirsuta. Dendrogrames based on genetic distances were constructed for the four botanical varieties, which revealed the existence of different clusters. It was concluded that there was abundant intra-variety SSR polymorphism, and with more and more SSR markers being developed, the intrinsic genetic diversity would be detected and the development of genetic map and marker-assisted selection for cultivated peanut would be feasible. 展开更多
关键词 Arachis hypogaea SSR genetic diversity differentiation index
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Anisotropy rock physics model for the Longmaxi shale gas reservoir,Sichuan Basin,China 被引量:9
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作者 刘喜武 郭智奇 +1 位作者 刘财 刘宇巍 《Applied Geophysics》 SCIE CSCD 2017年第1期21-30,188,共11页
The preferred orientation of clay minerals dominates the intrinsic anisotropy of shale. We introduce the clay lamination (CL) parameter to the Backus averaging method to describe the intrinsic shale anisotropy induc... The preferred orientation of clay minerals dominates the intrinsic anisotropy of shale. We introduce the clay lamination (CL) parameter to the Backus averaging method to describe the intrinsic shale anisotropy induced by the alignment of clay minerals. Then, we perform the inversion of CL and the Thomsen anisotropy parameters. The direct measurement of anisotropy is difficult because of the inability to measure the acoustic velocity in the vertical direction in boreholes and instrument limitations. By introducing the parameter CL, the inversion method provides reasonable estimates of the elastic anisotropy in the Longmaxi shale. The clay content is weakly correlated with the CL parameter. Moreover, the parameter CL is abnormally high at the bottom of the Longmaxi and Wufeng Formations, which are the target reservoirs. Finally, we construct rock physics templates to interpret well logging and reservoir properties. 展开更多
关键词 Longmaxi SHALE ANISOTROPY rock physics clay lamination
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Numerical simulation of rock electrical properties based on digital cores 被引量:11
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作者 刘学锋 孙建孟 王海涛 《Applied Geophysics》 SCIE CSCD 2009年第1期1-7,102,共8页
In this paper, we obtained three dimensional digital cores using X-ray CT to describe the rock microstructure and applied the open morphology algorithm to simulate oil and formation water distribution in the pore spac... In this paper, we obtained three dimensional digital cores using X-ray CT to describe the rock microstructure and applied the open morphology algorithm to simulate oil and formation water distribution in the pore space at different water saturations during the oil-displacing water flood process. The resistivity, formation factor, and resistivity index of rocks were calculated using the finite element method (FEM) and we studied the effect of rock wettability on electrical properties. The numerical simulation results indicate that the simulated formation factor and resistivity index of the water wet rock agrees well with experiments over the whole range of water saturation and extends the traditional resistivity experiment. The rock wettablilty has a large influence on the rock resistivity index. The resistivity and saturation exponent of oil wet rock are obviously larger than three of water wet rock. 展开更多
关键词 digital core MORPHOLOGY WETTABILITY resistivity index
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Microstructure evolution and grain growth behavior of Ti14 alloy during semi-solid isothermal process 被引量:6
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作者 陈永楠 魏建锋 +1 位作者 赵永庆 郑晶 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第5期1018-1022,共5页
Microstructure evolution of Ti14 (α+Ti2Cu) alloy during semi-solid isothermal process at different temperatures was investigated. The results reveal that both the temperature and holding time have effect on the gr... Microstructure evolution of Ti14 (α+Ti2Cu) alloy during semi-solid isothermal process at different temperatures was investigated. The results reveal that both the temperature and holding time have effect on the grain growth behavior. The grains grow obviously and the degree of globularity increases with the increase of holding time. According to the statistic analysis of experimental data, the grain growth indices are 0.88 and 0.97 at 1 000 ℃ and 1 050 ℃, respectively, which indicates that increasing isothermal temperature would accelerate microstructural evolution. 展开更多
关键词 titanium alloy Ti14 alloy SEMI-SOLID microstructure grain growth index
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FLIGHT CONFLICT FO RECASTING BASED ON CHAOTIC TIME SERIES 被引量:13
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作者 李善梅 徐肖豪 孟令航 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第4期388-394,共7页
In order to grasp the evolution of flight conflict amount accurately and to forecast the amount, chaos in flight conflicts is studied. Firstly, a fault tree of flight conflicts is established based on the man-machine-... In order to grasp the evolution of flight conflict amount accurately and to forecast the amount, chaos in flight conflicts is studied. Firstly, a fault tree of flight conflicts is established based on the man-machine-environ- ment system engineering theory. The chaotic characteristics of flight conflict are analyzed from the qualitative point of view. Secondly, an improved chaotic algorithm for the largest Lyapunov exponent is proposed based on the small-data method and the wavelet de-noising theory. Chaos in flight conflict time series is identified by the improved chaotic algorithm from the quantitative point of view. Finally, a case study by the chaos forecasting al- gorithm is performed and the results are evaluated by the gray error checking : Correlative value of posterior error is 0. 220 9〈0. 35, and micro-error probability is 0. 985 3〉0.95. Such results show the chaos forecasting algo- rithm is effective, thus it is feasible to analyze and forecast flight conflict by chaotic theory. 展开更多
关键词 flight conflict system engineering theory chaos theory fault tree Lyapunov exponent
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Numerical simulation of LWD resistivity response of carbonate formation using self-adaptive hp-FEM 被引量:4
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作者 刘得军 马中华 +2 位作者 邢晓楠 李辉 郭智勇 《Applied Geophysics》 SCIE CSCD 2013年第1期97-108,119,120,共14页
Most of the carbonate formation are highly heterogeneous with cavities of different sizes, which makes the prediction of cavity-filled reservoir in carbonate rocks difficult. Large cavities in carbonate formations pos... Most of the carbonate formation are highly heterogeneous with cavities of different sizes, which makes the prediction of cavity-filled reservoir in carbonate rocks difficult. Large cavities in carbonate formations pose serious threat to drilling operations. Logging-whiledrilling (LWD) is currently used to accurately identify and evaluate cavities in reservoirs during drilling. In this study, we use the self-adaptive hp-FEM algorithm simulate and calculate the LWD resistivity responses of fracture-cavity reservoir cavities. Compared with the traditional h-FEM method, the self-adaptive hp-FEM algorithm has the characteristics of the self-adaptive mesh refinement and the calculations exponentially converge to highly accurate solutions. Using numerical simulations, we investigated the effect of the cavity size, distance between cavity and borehole, and transmitted frequency on the LWD resistivity response. Based on the results, a method for recognizing cavities is proposed. This research can provide the theoretical basis for the accurate identification and quantitative evaluation of various carbonate reservoirs with cavities encountered in practice. 展开更多
关键词 LWD resistivity HP-FEM SELF-ADAPTIVE exponential convergence numerical simulation cavity RESERVOIRS
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Intra-annual Vegetation Change Characteristics in the NDVI-Ts Space:Application to Farming-Pastoral Zone in North China 被引量:6
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作者 陈云浩 李晓兵 +2 位作者 史培军 窦闻 李霞 《Acta Botanica Sinica》 CSCD 2003年第10期1139-1145,共7页
Land use/land cover change (LUCC) mapping and analysis using multi-temporal normalize difference vegetation index (NDVI) data have been well documented. Recent empirical studies have documented that many new methods w... Land use/land cover change (LUCC) mapping and analysis using multi-temporal normalize difference vegetation index (NDVI) data have been well documented. Recent empirical studies have documented that many new methods with high accuracy of retrieved land surface temperature ( Ts) have been developed. Thus, the combination of land surface temperature and NDVI has the greatest potential to improve the surface vegetation dynamic monitoring. In this study, the following objectives are pursued to: (1) introduce the practical method to produce the Ts, NDVI and Ts/NDVI based on remotely sensed data; (2) investigate the different retrieved result of vegetation cover information from NDVI, Ts and Ts/NDVI data sets, and analyze the intra-annual time trajectories of different vegetation cover categories in the NDVI- Ts space for farming-pastoral zone in North China, and (3) quantitative analysis the difference in using NDVI, Ts and Ts/NDVI data sets to express information based on the indices (information entropy and averaged information grads), and evaluate the relative role of Ts/NDVI data set in the discrimination of different vegetation cover categories through comparison to traditional NDVI data set. 展开更多
关键词 vegetation index land surface temperature NDVI-Ts space information entropy
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High temperature tensile deformation behavior of AZ80 magnesium alloy 被引量:4
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作者 乔军 边福勃 +1 位作者 何敏 王瑜 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第10期2857-2862,共6页
Tensile behaviors of an AZS0 alloy were investigated by elongation-to-failure tensile tests at 300, 350, 400 and 450 ℃, and strain rates of 10-2 and 10-3 s 1. Strain-rate-change tests from 5×10-5 s-1 to 2x10-2 s... Tensile behaviors of an AZS0 alloy were investigated by elongation-to-failure tensile tests at 300, 350, 400 and 450 ℃, and strain rates of 10-2 and 10-3 s 1. Strain-rate-change tests from 5×10-5 s-1 to 2x10-2 s-1 were applied to study deformation mechanisms. The experimental data show that the material exhibits enhanced tensile ductilities of over 100% at 400 and 450 ℃ with stress exponent of 4.29 and activation energy of 149.60 kJ/mol, and initial fine grains preserve in evenly deformed gauge based on microstructure studies. The enhanced tensile ductilities are rate controlled by a competitive mechanism of grain boundary sliding and dislocation climb creep, based on which a model can successfully simulate the deformation behavior. 展开更多
关键词 AZ80 magnesium alloy tensile behavior SUPERPLASTICITY CREEP stress exponent
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RITSD Analysis of the Agronomic Traits of Somaclonal in Rice 被引量:6
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作者 谢戎 杨正林 +3 位作者 刘成元 李永洪 桑贤春 何光华 《Agricultural Science & Technology》 CAS 2010年第1期36-41,共6页
[Objective]The aim was to study the sensitive response characteristics of the main agronomic traits of somaclonal and the variation of sensitive response of the lines of somaclonal to sowing date. [Method]The RITSD ch... [Objective]The aim was to study the sensitive response characteristics of the main agronomic traits of somaclonal and the variation of sensitive response of the lines of somaclonal to sowing date. [Method]The RITSD changing of agronomic traits was studied by using 24 rice somaclonal and its donor parent under two sowing dates. [Result]The average values of RITSD were higher (over one) for the traits of pant height (PH),density of spikelets (DS),filled spikelets per panicle (FSP),spikelets per panicle (SP) and grain weight per plant (GWP),but lower for days of sowing to heading (DSH),effective panicles (EP),panicle length (PL),seed setting rate (SS) and 1 000-grain weight (1 000-GW). These showed that PH,DS,FSP,SP and GWP were easily affected by sowing date and tended to higher with the later sowing; the RITSD of somaclonal changed with the agronomic traits. The frequency of RITSD' variation of DSH and PH was higher than that of PL. The RITSD' value of EP,PL,DS,FSP,SP and SS became higher,and higher or lower for DSH and GWP in different somaclonal; compared with the donor,20 of 24 was significantly different,and the frequency of RITSD variation was over 83. 3%,however,RITSD of the most lines (75%) changed only for 1-2 characters; cluster analysis showed that the RITSD of agronomic traits belonged to different combinations of somaclonal in rice. [Conclusion]the study had provided a theoretical basis for the screening and using of the somaclonal. 展开更多
关键词 Rice (Oryza sativa L.) Somaclonal Respondence Index of Trait to Sowing Date (RITSD) Agronomic traits VARIATION
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