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1.
相对于max型表现外延,给出min型表现外延的定义,利用min型表现外延构造了概念关于因素的min型反馈外延.研究了min型反馈外延与概念外延以及复杂因素min型反馈外延与简单因素min型反馈外延之间的关系,得到了与min型反馈外延相关的一些重要性质.定义了min型反馈外延外包络,给出一种从概念外延"内部"对概念外延进行逼近的方法.  相似文献   

2.
边境型旅游地是区别于内地型旅游地的一种独特类型。通过实地考察、游客调查问卷数据和相关资料,研究人员分析了延边朝鲜族自治州旅游客源市场空间结构特征,并从国际、国内两种角度将边境型旅游地与内地的海滨型、山岳观光型、城市型、古村落型旅游地以及其他不同地域的边境型旅游地的客源市场空间结构进行了对比分析,揭示了边境型旅游地的客流特征,并就如何促进边境型旅游地旅游业的进一步发展提出了建议。  相似文献   

3.
通过对W型钢带的结构和材料的改进,设计出复合材料π型带,并与W型钢带进行了有限元分析比较,得出了复合材料π型带优于w型钢带的结论.  相似文献   

4.
Java泛型     
本文通过实例介绍了Java泛型编程方法.首先详细介绍Java泛型类的定义、使用,进而举例说明引入Java泛型的好处,也阐明了使用Java泛型一些常常被忽略的注意事项.最后简单介绍了泛型接口和泛型方法.  相似文献   

5.
回顾了二型模糊集合的基本概念与运算方法,重点介绍了二型模糊逻辑系统及区间二型模糊系统的相关知识,概述了二型模糊系统近几年的成功应用案例,最后总结了二型模糊系统的不足以及发展方向.  相似文献   

6.
本文介绍了阻燃剂及反应型阻燃剂的研究现状,并简述了几类反应型阻燃剂的性能特点和发展情况,展望了反应型型阻燃剂的发展前景和方向。  相似文献   

7.
研究D型隶属函数与O型隶属函数的关系,证明了确定X上一个D型隶属函数等价于确定X上一个O型隶属函数和X×X上一个O型隶属函数。并讨论了D型隶属函数与聚类的关系,对D型模糊集和O型模糊集分别定义了模糊度且研究了相应的性质。  相似文献   

8.
研究了采用"A"型架的车辆在振动过程中传动系统万向节安装角度的变化情况,及其引起的传动系统转速波动.传动系统的布置型式可以是Z型或W型,比较了不同的布置型式对传动系统转速波动的影响.后桥振动过程中传动轴转过的角度小于"A"型架转过的角度时,采用W型布置产生的速度波动要优于Z型布置.给出了Z型和W型布置的传动系统中后桥安装角度的求解方法,以及对于特定的采用"A"型架的车型传动系统采用Z型还是W型布置的判断方法.  相似文献   

9.
小野1A是由小粒野生稻(Oryza minuta Presl.)中天然不育株与Y58S/内香B杂种后代优秀单株经多代回交转育而成。由于该雄性不育细胞质来自小粒野生稻,称为XY型雄性不育细胞质。恢保关系鉴定结果表明,XY型细胞质雄性不育系与野败型(WA)、印尼水田谷型(ID)、K型和红莲型(HL)细胞质雄性不育系的恢保关系不同,WA型、ID型、K型和HL型的保持系和恢复系中部分可以作为XY型雄性不育细胞质的保持系,部分可以作为XY型雄性不育细胞质的恢复系。XY型雄性不育细胞质突破了WA型、ID型、K型和HL型等雄性不育细胞质的恢保关系,扩大了保持系育种范围,可以用品质优良的栽培品种培育出高标准优质米不育系。由此可见,XY型雄性不育细胞质的发掘,不仅丰富了杂交稻细胞质遗传多样性,而且为培育高标准优质米不育系、进而实质性提高杂交稻稻米品质开辟了一条崭新的育种途径。  相似文献   

10.
涡旋压缩机通用涡旋型线泛函集成研究   总被引:2,自引:0,他引:2  
研究了平面曲线固有弧微分方程理论,利用切向角和曲率半径的固有弧微分方程形式和广义泛函理论,推导出了弧微分方程和笛卡尔坐标之间的变换方法,提出了涡旋型线的渐开特性条件。根据Taylor级数对等思想,建立了涡旋型线的广义泛函集成型线的统一形式,发展并完善了现有涡旋型线通用方程理论,并具体分析推导了4种典型的涡旋型线。突破了涡旋型线数学模型固有特性的限制,提出的表征涡旋型线本质特征的根本因素——涡旋型线的形函数统一形式,为涡旋压缩机型线的设计理论与方法研究拓宽了思路。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

16.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

17.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

18.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

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