期刊文献+
共找到1,232篇文章
< 1 2 62 >
每页显示 20 50 100
Type Synthesis for 4-DOF Parallel Press Mechanism Using G_F Set Theory 被引量:21
1
作者 HE Jun GAO Feng +1 位作者 MENG Xiangdun GUO Weizhong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第4期851-859,共9页
Parallel mechanisms is used in the large capacity servo press to avoid the over-constraint of the traditional redundant actuation. Currently, the researches mainly focus on the performance analysis for some specific p... Parallel mechanisms is used in the large capacity servo press to avoid the over-constraint of the traditional redundant actuation. Currently, the researches mainly focus on the performance analysis for some specific parallel press mechanisms. However, the type synthesis and evaluation of parallel press mechanisms is seldom studied, especially for the four degrees of freedom(DOF) press mechanisms. The type synthesis of 4-DOF parallel press mechanisms is carried out based on the generalized function(GF) set theory. Five design criteria of 4-DOF parallel press mechanisms are firstly proposed. The general procedure of type synthesis of parallel press mechanisms is obtained, which includes number synthesis, symmetrical synthesis of constraint GF sets, decomposition of motion GF sets and design of limbs. Nine combinations of constraint GF sets of 4-DOF parallel press mechanisms, ten combinations of GF sets of active limbs, and eleven combinations of GF sets of passive limbs are synthesized. Thirty-eight kinds of press mechanisms are presented and then different structures of kinematic limbs are designed. Finally, the geometrical constraint complexity(GCC), kinematic pair complexity(KPC), and type complexity(TC) are proposed to evaluate the press types and the optimal press type is achieved. The general methodologies of type synthesis and evaluation for parallel press mechanism are suggested. 展开更多
关键词 parallel mechanism type synthesis GF set type evaluation press mechanism
在线阅读 下载PDF
Evaluation of sensory properties and their correlation coefficients with physico-chemical indices in Turkish set-type yoghurts 被引量:1
2
作者 Zehra Güler Young W. Park 《Open Journal of Animal Sciences》 2011年第1期9-15,共7页
Sensory properties and physico-chemical parameters of 10 most popular brands of commercial set-type Turkish yoghurts were evaluated and correlation coefficients between the two indices were investigated. The results i... Sensory properties and physico-chemical parameters of 10 most popular brands of commercial set-type Turkish yoghurts were evaluated and correlation coefficients between the two indices were investigated. The results indicated that increases in volatile compounds (acetaldehyde, 2-butanone, 2-nanonane, ethyl acetate), titratable acidity, ash and fat contents inversely correlated with the overall acceptability score of the yoghurt. However, diacetyl, C4 to C12 free fatty acids, pH, whiteness index and texture positively correlated with overall acceptability of the yoghurt products. It was concluded that the acceptability of the Turkish set-type yoghurts is mainly governed by the fifteen volatile compounds as well as the physico-chemical properties determined. Thus, the overall acceptability of the yoghurts was not influenced by a single characteristic, but rather by complex in nature. 展开更多
关键词 TURKISH set-type YOGHURT SENSORY properties PHYSICO-CHEMICAL parameters correlation coefficient
暂未订购
Entropy measures of type-2 intuitionistic fuzzy sets and type-2 triangular intuitionistic trapezodial fuzzy sets 被引量:2
3
作者 Zhensong Chen Shenghua Xiong +1 位作者 Yanlai Li Kwai-Sang Chin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第4期774-793,共20页
In order to measure the uncertain information of a type- 2 intuitionistic fuzzy set (T21FS), an entropy measure of T21FS is presented by using the constructive principles. The proposed entropy measure is also proved... In order to measure the uncertain information of a type- 2 intuitionistic fuzzy set (T21FS), an entropy measure of T21FS is presented by using the constructive principles. The proposed entropy measure is also proved to satisfy all of the constructive principles. Further, a novel concept of the type-2 triangular in- tuitionistic trapezoidal fuzzy set (T2TITrFS) is developed, and a geometric interpretation of the T2TITrFS is given to comprehend it completely or correctly in a more intuitive way. To deal with a more general uncertain complex system, the constructive principles of an entropy measure of T2TITrFS are therefore proposed on the basis of the axiomatic definition of the type-2 intuitionisic fuzzy entropy measure. This paper elicits a formula of type-2 triangular intuitionistic trapezoidal fuzzy entropy and verifies that it does sa- tisfy the constructive principles. Two examples are given to show the efficiency of the proposed entropy of T2TITrFS in describing the uncertainty of the type-2 intuitionistic fuzzy information and illustrate its application in type-2 triangular intuitionistic trapezodial fuzzy decision making problems. 展开更多
关键词 type-2 intuitionistic fuzzy set intuitionistic fuzzy en-tropy type-2 triangular intuitionistic trapezoidal fuzzy entropy.
在线阅读 下载PDF
Linguistic Dynamic Modeling and Analysis of Psychological Health State Using Interval Type-2 Fuzzy Sets 被引量:9
4
作者 Hong Mo Jie Wang +1 位作者 Xuan Li Zhanlin Wu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI 2015年第4期366-373,共8页
The study of psychological health state is helpful to build appropriate models and take effective intervention strategies, and the results benefit the intervened released from psychological distress within the shortes... The study of psychological health state is helpful to build appropriate models and take effective intervention strategies, and the results benefit the intervened released from psychological distress within the shortest possible time. In this paper, interval type-2 fuzzy sets and fuzzy comprehension evaluation are applied in the analysis of mental health status and crisis intervention. A closed-loop linguistic dynamic intervention model for psychological health state is built. Linguistic dynamic systems based on interval type-2 fuzzy sets are used to describe and analyze the evolutionary process of psychological health status. © 2014 Chinese Association of Automation. 展开更多
关键词 Computational linguistics Fuzzy sets LINGUISTICS
暂未订购
The Hausdorff Dimension and Hausdorff Measure of Full Parry Measure Subset of Finite Type
5
作者 尹建东 周作领 《Northeastern Mathematical Journal》 CSCD 2006年第1期114-118,共5页
All the full Parry measure subsets of a given subshift of finite type determined by an irreducible 0-1 matrix have the same Hausdorrf dimension and Hausdorff measure which coincide with those of the set of finite type.
关键词 chaotic set set of finite type Hausdorff dimension Hausdorff measure
在线阅读 下载PDF
Traffic Flow Data Forecasting Based on Interval Type-2 Fuzzy Sets Theory 被引量:5
6
作者 Runmei Li Chaoyang Jiang +1 位作者 Fenghua Zhu Xiaolong Chen 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI 2016年第2期141-148,共8页
This paper proposes a long-term forecasting scheme and implementation method based on the interval type-2 fuzzy sets theory for traffic flow data. The type-2 fuzzy sets have advantages in modeling uncertainties becaus... This paper proposes a long-term forecasting scheme and implementation method based on the interval type-2 fuzzy sets theory for traffic flow data. The type-2 fuzzy sets have advantages in modeling uncertainties because their membership functions are fuzzy. The scheme includes traffic flow data preprocessing module, type-2 fuzzification operation module and long-term traffic flow data forecasting output module, in which the Interval Approach acts as the core algorithm. The central limit theorem is adopted to convert point data of mass traffic flow in some time range into interval data of the same time range (also called confidence interval data) which is being used as the input of interval approach. The confidence interval data retain the uncertainty and randomness of traffic flow, meanwhile reduce the influence of noise from the detection data. The proposed scheme gets not only the traffic flow forecasting result but also can show the possible range of traffic flow variation with high precision using upper and lower limit forecasting result. The effectiveness of the proposed scheme is verified using the actual sample application. © 2014 Chinese Association of Automation. 展开更多
关键词 Data handling Forecasting Fuzzy sets Membership functions Uncertainty analysis
在线阅读 下载PDF
INTEGRABLE TYPES OF NONLINEAR ORDINARY DIFFERENTIAL EQUATION SETS OF HIGHER ORDERS
7
作者 汤光宋 原存德 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1995年第9期883-890,共8页
Because of the extensive applications of nonlinear ordinary differential equation in physics,mechanics and cybernetics,there have been many papers on the exact solution to differential equation in some major publicati... Because of the extensive applications of nonlinear ordinary differential equation in physics,mechanics and cybernetics,there have been many papers on the exact solution to differential equation in some major publications both at home and abroad in recent years Based on these papers and in virtue of Leibniz formula,and transformation set technique,this paper puts forth the solution to nonlinear ordinary differential equation set of higher-orders, moveover,its integrability is proven.The results obtained are the generalization of those in the references. 展开更多
关键词 nonlinear ordinary differential equation set.transformation set.integrable type
在线阅读 下载PDF
Mathematical Model and Geometrical Model of Double Pitch ZN-type Worm Gear Set Based on Generation Mechanism 被引量:2
8
作者 SHU Linsen CAO Huajun +2 位作者 LI Xianchong ZHANG Chenglong LI Yuxia 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第3期549-555,共7页
The current researches on the tooth surface mathematical equations and the theory of gearing mainly pay attention to the ordinary type worm gear set(e.g., ZN, ZA, or ZK). The research of forming mechanism and three-... The current researches on the tooth surface mathematical equations and the theory of gearing mainly pay attention to the ordinary type worm gear set(e.g., ZN, ZA, or ZK). The research of forming mechanism and three-dimensional modeling method for the double pitch worm gear set is not enough. So there are some difficulties in mathematical model deducing and geometry modeling of double pitch ZN-type worm gear set based on generation mechanism. In order to establish the mathematical model and the precise geometric model of double pitch ZN-type worm gear set, the structural characteristics and generation mechanism of the double pitch ZN-type worm gear set are investigated. Mathematical model of the ZN-type worm gear set is derived based on its generation mechanism and the theory of gearing. According to the mathematical model of the worm gear set which has been developed, a geometry modeling method of the double pitch ZN-type worm and worm gear is presented. Furthermore, a geometrical precision calculate method is proposed to evaluate the geometrical quality of the double pitch worm gear set. As a result, the maximum error is less than 6′10–4 mm in magnitude, thus the model of the double pitch ZN-type worm gear set is available to meet the requirements of finite element analysis and engineering application. The derived mathematical model and the proposed geometrical modeling method are helpful to guiding the design, manufacture and contact analysis of the worm gear set. 展开更多
关键词 double pitch ZN-type worm gear set generation mechanism mathematical model geometrical model
在线阅读 下载PDF
Long-term Traffic Volume Prediction Based on K-means Gaussian Interval Type-2 Fuzzy Sets 被引量:11
9
作者 Runmei Li Yinfeng Huang Jian Wang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2019年第6期1344-1351,共8页
This paper uses Gaussian interval type-2 fuzzy se theory on historical traffic volume data processing to obtain a 24-hour prediction of traffic volume with high precision. A K-means clustering method is used in this p... This paper uses Gaussian interval type-2 fuzzy se theory on historical traffic volume data processing to obtain a 24-hour prediction of traffic volume with high precision. A K-means clustering method is used in this paper to get 5 minutes traffic volume variation as input data for the Gaussian interval type-2 fuzzy sets which can reflect the distribution of historical traffic volume in one statistical period. Moreover, the cluster with the largest collection of data obtained by K-means clustering method is calculated to get the key parameters of type-2 fuzzy sets, mean and standard deviation of the Gaussian membership function.Using the range of data as the input of Gaussian interval type-2 fuzzy sets leads to the range of traffic volume forecasting output with the ability of describing the possible range of the traffic volume as well as the traffic volume prediction data with high accuracy. The simulation results show that the average relative error is reduced to 8% based on the combined K-means Gaussian interval type-2 fuzzy sets forecasting method. The fluctuation range in terms of an upper and a lower forecasting traffic volume completely envelopes the actual traffic volume and reproduces the fluctuation range of traffic flow. 展开更多
关键词 GAUSSIAN interval type-2 fuzzy sets K-MEANS clustering LONG-TERM PREDICTION TRAFFIC VOLUME TRAFFIC VOLUME fluctuation range
暂未订购
LEVEL SETS AND EQUIVALENCES OF MORAN-TYPE SETS
10
作者 杜亚丽 苗俊杰 吴敏 《Acta Mathematica Scientia》 SCIE CSCD 2016年第5期1343-1357,共15页
In the paper, we consider Moran-type sets E;given by sequences {a;};and{n;};. we prove that E;may be decompose into the disjoint union of level sets. Moreover,we define three type of equivalence between two dimension ... In the paper, we consider Moran-type sets E;given by sequences {a;};and{n;};. we prove that E;may be decompose into the disjoint union of level sets. Moreover,we define three type of equivalence between two dimension functions associated to two Morantype sets, respectively, and we classify Moran-type sets by these equivalent relations. 展开更多
关键词 Moran-type sets dimension function level set logarithmical equivalence
在线阅读 下载PDF
Geological Features,Mineralization Types and Metallogenic Setting of the Phlaythong Large Iron Deposit,Southern Laos
11
作者 LIU Shusheng FAN Wenyu +1 位作者 LUO Maojin YANG Yongfei 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第4期1423-1424,共2页
The Phlaythong large iron deposit in Shampasak of southern Laos,is located in the Kon Tum microblock (Fig.1A),central-southern part of the Indo-China block,and the geographic coordinate of the central mining area is... The Phlaythong large iron deposit in Shampasak of southern Laos,is located in the Kon Tum microblock (Fig.1A),central-southern part of the Indo-China block,and the geographic coordinate of the central mining area is 14°43′04″ N and 106°07′02″ E. 展开更多
关键词 Geological Features Mineralization types and Metallogenic setting of the Phlaythong Large Iron Deposit Southern Laos TFe
在线阅读 下载PDF
Geochemical Types of Granitoids of the Mongol-Okhotsk Belt and Their Geodynamic Settings 被引量:1
12
作者 MIKHAILI.KUZMIN VICTORS.ANTIPIN 《Chinese Journal Of Geochemistry》 EI CAS 1993年第2期110-117,共8页
The following geochemical types of granitoids have been investigated in the Mongol-Okhotsk belt:tholetitic,palingenic calc-alkaline,latitic,plumasitic and arpaitic rare-metal granites.Plagiogranites of the tholeiitic ... The following geochemical types of granitoids have been investigated in the Mongol-Okhotsk belt:tholetitic,palingenic calc-alkaline,latitic,plumasitic and arpaitic rare-metal granites.Plagiogranites of the tholeiitic series occur within the Mongol-Okhotsk suture,indicating a subduction environment.The calc-alkaline granitoids responsible for the batholith-like intrusions and their formation are related to collision environments.The latest granitoids of the latite series and rare-metal granites came into existence after the collision of continental masses,providing evidence of intraplate magmatism. 展开更多
关键词 地球化学 花岗岩 地球动力学 斑英安岩
在线阅读 下载PDF
基于混合核模糊熵的多类型数据属性约简算法
13
作者 贾润亮 张海玉 《计算机工程与设计》 北大核心 2025年第7期1864-1873,共10页
为解决模糊粗糙集属性约简中模糊相似关系运算的不合理性以及多类型数据的不适用性,提出一种基于混合核模糊熵的多类型数据属性约简算法。提出基于核函数的多类型属性模糊关系计算方法,称之为混合核函数度量,并构造出相应的模糊信息粒... 为解决模糊粗糙集属性约简中模糊相似关系运算的不合理性以及多类型数据的不适用性,提出一种基于混合核模糊熵的多类型数据属性约简算法。提出基于核函数的多类型属性模糊关系计算方法,称之为混合核函数度量,并构造出相应的模糊信息粒化模型;利用混合核函数度量进一步提出多类型数据的模糊互补信息熵模型和相关性质;利用模糊互补条件熵和模糊互补互信息熵,提出多类型数据信息系统的不确定性度量和属性约简。实验结果验证了所提出不确定性度量和属性约简方法在多类型数据上的有效性。 展开更多
关键词 模糊粗糙集 多类型属性 核函数 信息熵 条件熵 互信息熵 不确定性度量 属性约简
在线阅读 下载PDF
基于二型双极值模糊方法的空中目标威胁评估
14
作者 解维河 王学良 +1 位作者 李晓芳 刘琳 《指挥控制与仿真》 2025年第4期94-98,共5页
针对水面舰艇防空作战中空中目标复杂信息的快速决策处理问题,依据二型双极值模糊集的定义和基本运算,利用二型直觉模糊综合评价方法创新提出了二型双极值模糊综合评价方法,给出了七步具体操作步骤和二型双极值模糊集具体隶属函数构建方... 针对水面舰艇防空作战中空中目标复杂信息的快速决策处理问题,依据二型双极值模糊集的定义和基本运算,利用二型直觉模糊综合评价方法创新提出了二型双极值模糊综合评价方法,给出了七步具体操作步骤和二型双极值模糊集具体隶属函数构建方法,将其应用于水面舰艇抗击空中目标威胁评估,对此进行了分析和检验并得到了较好的效果,该评价方法能够很好地解决多属性因素目标威胁评估问题,为水面舰艇防空作战多目标复杂信息处理提供了一种有效方法。 展开更多
关键词 威胁评估 直觉模糊集 二型双极值模糊集 模糊综合评价
在线阅读 下载PDF
航空器机坪运行安全关键风险因素识别及作用机理研究
15
作者 李明捷 殷天策 冯思蓉 《安全与环境学报》 北大核心 2025年第6期2072-2079,共8页
为提高航空器在机坪区域运行过程的安全水平,提升机坪运行效率,引入扎根理论,通过对某地区管理局共计17起典型航空器机坪事件进行分析,识别出11个威胁航空器机坪运行安全的风险因素;然后,构建基于区间二型模糊数(Interval Type-2 Fuzzy ... 为提高航空器在机坪区域运行过程的安全水平,提升机坪运行效率,引入扎根理论,通过对某地区管理局共计17起典型航空器机坪事件进行分析,识别出11个威胁航空器机坪运行安全的风险因素;然后,构建基于区间二型模糊数(Interval Type-2 Fuzzy Set, IT2FS)及有序加权平均算子(Ordered Weighted Averaging operator, WOA)的改进决策试验与评估实验法(Decision-Making Trial and Evaluation Laboratory, DEMATEL)模型对航空器机坪运行风险因素两两之间的关系进行定量化分析。结果表明,人员素质S1(10.34)、监管S11(9.96)、操作行为S2(9.94)、培训管理S9(9.90)中心度最高,在指标体系中处于重要的位置,可为机场制定机坪运行安全策略提供理论参考。 展开更多
关键词 安全工程 扎根理论 区间二型模糊数 有序加权平均算子 决策试验与评估实验法
原文传递
基于结构元理论的正规Type-2模糊集的质心 被引量:1
16
作者 郭嗣琮 任燕 杨洋 《控制与决策》 EI CSCD 北大核心 2017年第4期734-740,共7页
定义正规Type-2模糊集,并利用结构元理论给出正规Type-2模糊集的结构元表示和正规Type-2模糊集质心计算的确切步骤,得出正规Type-2模糊集质心的精确解.在正规Type-2模糊集的次隶属函数可以通过结构元线性表示时,给出其质心计算的近似结... 定义正规Type-2模糊集,并利用结构元理论给出正规Type-2模糊集的结构元表示和正规Type-2模糊集质心计算的确切步骤,得出正规Type-2模糊集质心的精确解.在正规Type-2模糊集的次隶属函数可以通过结构元线性表示时,给出其质心计算的近似结果.实例比较结果表明,所提出的方法计算简便,适用范围广,且在一定条件下近似解与精确解的拟合较好. 展开更多
关键词 type-2模糊集 正规type-2模糊集 质心 解模糊
原文传递
基于Type-2 T-S的模糊脉冲控制 被引量:1
17
作者 李医民 孙源源 赵彤 《江苏大学学报(自然科学版)》 EI CAS 北大核心 2012年第4期491-496,共6页
利用Type-2模糊系统在描述复杂非线性系统诸多不确定性问题时的有效性,在Type-1模糊脉冲控制的基础上,提出了区间Type-2 T-S模糊脉冲控制方法.该方法利用Type-2模糊隶属函数的"宽带"效应,解决了Type-1模糊脉冲控制中数据噪声... 利用Type-2模糊系统在描述复杂非线性系统诸多不确定性问题时的有效性,在Type-1模糊脉冲控制的基础上,提出了区间Type-2 T-S模糊脉冲控制方法.该方法利用Type-2模糊隶属函数的"宽带"效应,解决了Type-1模糊脉冲控制中数据噪声和外界扰动问题;利用Lyapunov理论和Lipschitz条件,通过运用比较方法和线性矩阵不等式等综合方法,设计Type-2 T-S模糊脉冲控制器,给出系统的渐进稳定性分析;最后,在倒立摆系统的仿真中,较方便地确定了隶属函数并选取了较少的模糊规则,表明系统的有效性和优异性. 展开更多
关键词 T-S模糊系统 脉冲控制 区间type-2模糊集 稳定性 收敛性
在线阅读 下载PDF
九岭南缘宜丰—奉新锂矿田锂矿成岩成矿地质背景 被引量:1
18
作者 周建廷 罗微 +3 位作者 熊燃 肖业斌 张福神 邱文江 《地质科学》 北大核心 2025年第1期229-249,共21页
宜丰—奉新锂矿田是九岭南缘最新探明的世界级花岗岩型锂矿田。为了进一步研究九岭南缘成岩成矿地质背景和稀有金属成矿规律,笔者对与成矿有关的甘坊复式岩体进行了地质特征、地球化学和年代学研究,探讨了甘坊复式岩体侵入期次、构造环... 宜丰—奉新锂矿田是九岭南缘最新探明的世界级花岗岩型锂矿田。为了进一步研究九岭南缘成岩成矿地质背景和稀有金属成矿规律,笔者对与成矿有关的甘坊复式岩体进行了地质特征、地球化学和年代学研究,探讨了甘坊复式岩体侵入期次、构造环境和和岩浆源区。宜丰—奉新地区花岗岩型锂矿可划分为碱性长石花岗岩型和花岗细晶(斑)岩型两种类型。甘坊复式岩体(包括甘坊岩体、古阳寨岩体、武堂岩体和白水洞岩体)为一复式岩套,经历了燕山期早、晚两期4个阶段的岩浆作用。甘坊复式岩体出现4次成岩成矿高峰(期),早白垩世是该矿田锂矿主成矿期。甘坊复式岩体是九岭南缘地区同一岩浆源区经过多次重熔,不同阶段、不同期次侵位,高度分异演化,累积增长形成的。甘坊岩体、古阳寨岩体、武堂岩体和白水洞岩体是岩浆演化不同阶段的产物。成岩成矿作用是统一的热力学与地球化学成矿系统,时代越是往后,花岗岩演化程度越高越彻底,岩浆热液流体参与越明显,成矿作用也越强,成矿规模越大。花岗岩成因类型为S型花岗岩,其岩浆源区主要为成熟度较高的变质泥质岩和砂岩。成岩成矿处于陆内造山同碰撞后伸展构造环境。 展开更多
关键词 花岗岩型锂矿床 成岩成矿时代 伸展构造环境 S型花岗岩 宜丰—奉新锂矿田
在线阅读 下载PDF
内蒙古七家子早三叠世侵入岩成因及其地质意义
19
作者 任颖伟 王红 +2 位作者 董国臣 侯飞飞 梁景利 《现代地质》 北大核心 2025年第5期1232-1248,共17页
古亚洲洋的演化过程一直是地学研究的热点问题,特别是对其闭合时限及闭合后构造演化的研究。本文首次在内蒙古奈曼旗南部地区识别出一套由角闪辉长岩和花岗质岩石组成的基性-酸性杂岩体,通过开展锆石U-Pb定年和地球化学研究,限定其成岩... 古亚洲洋的演化过程一直是地学研究的热点问题,特别是对其闭合时限及闭合后构造演化的研究。本文首次在内蒙古奈曼旗南部地区识别出一套由角闪辉长岩和花岗质岩石组成的基性-酸性杂岩体,通过开展锆石U-Pb定年和地球化学研究,限定其成岩时代,同时探讨其成因联系、岩浆源区及构造背景。锆石U-Pb测年结果表明:角闪辉长岩、中粒二长花岗岩及细粒二长花岗岩的侵位年龄分别为(249.3±1.2)Ma、(247.4±2.8)Ma和(246.2±1.4)Ma,为早三叠世岩浆同时侵入的产物。地球化学数据显示,角闪辉长岩与花岗质岩体的SiO_(2)含量在50.78%~69.81%范围存在明显间断,表现出双峰式岩浆岩特征。角闪辉长岩属准铝质岩石,具有贫碱、高Ti、富Fe的特征,稀土元素总含量较高,Ce和Eu异常不明显(δCe=0.94~0.98,δEu=0.90~1.02);富集大离子亲石元素(Ba、Th、U),而亏损Nb、P、Ti等高场强元素。这些地球化学特征表明角闪辉长岩是由继承俯冲流体交代影响的岩石圈地幔部分熔融,并有部分壳源物质加入形成。花岗质岩体为一套高钾钙碱性,过铝质Ⅰ型花岗岩;具有相似的地球化学组成,均表现出富碱,贫Ca、Mg的特点,以及较高的微量元素含量,强烈Eu负异常和轻微Ce负异常;明显富集Rb、Th、K等大离子亲石元素,亏损Nb、Ta、Sr等高场强元素,均来源于地壳物质部分熔融,并表现出由细粒二长花岗岩向中粒二长花岗岩演化的趋势。结合岩体地球化学特征和区域已有研究资料,认为七家子杂岩体形成于碰撞后伸展环境,古亚洲洋闭合后俯冲板片断离,诱使具有俯冲组分特征的岩石圈地幔部分熔融,部分基性岩浆在上侵过程中受到壳源物质的混染形成角闪辉长岩;另一部分基性岩浆底侵烘烤下地壳,致使壳源物质部分熔融,而后同时侵位形成双峰式岩浆岩。 展开更多
关键词 古亚洲洋 早三叠世 双峰式岩浆岩 碰撞后伸展环境 Ⅰ型花岗岩 内蒙古 奈曼旗
在线阅读 下载PDF
红外图像的一种Type-Ⅱ模糊增强算法 被引量:1
20
作者 袁和金 张艳宁 +2 位作者 周涛 杨福增 赵文斌 《计算机工程与应用》 CSCD 北大核心 2007年第16期33-36,102,共5页
提出了一种基于Type-Ⅱ模糊集的红外图像增强算法,该算法首先根据像素的邻域相关性对图像进行预处理,然后以Ostu分割阈值为基础,构造了红外图像的Type-Ⅱ模糊特征平面;然后,采用不同的变换规则对图像进行模糊增强,并将结果进行融合;最后... 提出了一种基于Type-Ⅱ模糊集的红外图像增强算法,该算法首先根据像素的邻域相关性对图像进行预处理,然后以Ostu分割阈值为基础,构造了红外图像的Type-Ⅱ模糊特征平面;然后,采用不同的变换规则对图像进行模糊增强,并将结果进行融合;最后,通过Type reduction和去模糊化操作得到增强后的输出图像。对几幅典型的红外图像的增强实验表明,提出的方法能够有效地提高红外图像的对比度。 展开更多
关键词 type-Ⅱ模糊集 图像增强 红外图像
在线阅读 下载PDF
上一页 1 2 62 下一页 到第
使用帮助 返回顶部