圆齿行星传动运动特性

通过建立圆齿行星传动的运动学模型,根据齿轮啮合原理及瞬心推导出圆齿行星传动啮合的瞬时传动比计算公式,为精确分析研究圆齿的齿形替代、真实的运动情况提供理论依据,最后通过实例得出圆齿行星传动传动比的变化情况.     

圆齿行星传动运动特性

通过建立圆齿行星传动的运动学模型,根据齿轮啮合原理及瞬心推导出圆齿行星传动啮合的瞬时传动比计算公式,为精确分析研究圆齿的齿形替代、真实的运动情况提供理论依据,最后通过实例得出圆齿行星传动传动比的变化情况。     

钢/塑齿轮组合行星传动的振动特性研究

为了深入了解钢质行星齿轮传动系统引入塑料齿轮后的振动特性,文中建立了钢/塑齿轮组合行星传动的动力学分析模型和实验模型,对4种钢/塑齿轮组合行星传动的振动特性进行了理论分析与实验研究,分析了组合方式对行星传动振动特性的影响。数值仿真与实验研究结果表明：塑料齿轮的引入对行星齿轮传动的振动特性影响很大,显著地减小了太阳轮-行星轮和内齿圈-行星轮的啮合动载荷;有效地抑制了行星齿轮传动的齿轮啮合频带振动和高频带振动;组合方式对行星齿轮传动的振动特性影响显著,合理地采用钢/塑齿轮组合行星传动结构可以极大地降低啮合动载荷,从而显著地降低传动系统的振动和噪声。     

多级行星轮系结构与运动拓扑模型的图形符号描述方法及其运动学分析

由于多级行星轮系包含的构件多,结构复杂,使得对其传动系统的结构特征与运动学分析变得十分困难。本文提出了多级行星轮系结构与运动拓扑模型的图形符号描述新方法,该方法通过引入描述多级行星轮系统结构拓扑模型和运动拓扑模型的新图形符号,利用图形符号表示出多级行星轮系中各构件以及构件之间的联接特征;通过定义拓扑演变方式和转换规则,建立能够完整描述多级行星轮系结构特征与运动特性信息的图形符号拓扑模型,实现了多级行星齿轮机构与拓扑模型的一一对应关系。研究结果表明,该方法能够建立多级行星轮系结构-运动的图形符号拓扑模型,可以比较直观地反映出多级行星轮系的结构特征,简化了多级行星轮系的同构识别以及运动学分析。研究结果可为多级行星轮系的创新设计和分析提供一种简单可行的新途径。     

钢／塑齿轮组合行星传动系统的振动特性

为了解钢质行星齿轮传动系统引入塑料齿轮后的振动特性,建立了钢/塑齿轮组合行星传动的动力学分析模型和实验模型,对4种钢/塑齿轮组合行星传动系统的振动特性进行了理论分析与实验研究,分析了组合方式对行星传动振动特性的影响.数值仿真与实验研究结果表明:塑料齿轮的引入对行星齿轮传动的振动特性影响很大,显著减小了太阳轮-行星轮和内齿圈-行星轮的啮合动载荷,有效抑制了行星齿轮传动的齿轮啮合频带振动和高频带振动;组合方式对行星齿轮传动的振动特性影响显著,合理地采用钢/塑齿轮组合行星传动结构可以极大地降低啮合动载荷,从而显著地降低传动系统的振动和噪声.     

论二齿差变位内齿轮行星减速机构

二齿差变位内齿轮行星减速机构是我参加研制的一项实用新型专利。行星齿轮传动机构和少齿差行星减速机构被广泛应用于各领域,虽然传统的行星齿轮减速机构有很多优点,但仍然存在单级减速比较小的缺点,而少齿差行星减速机构单级减速比虽然大一些,但传动平稳性差,传动精度低,在需要大减速比的情况下,需要经过多级减速才能达到目的,这样会造成结构复杂,体积增大,制造成本增加,同时多级传动也降低了传动效率和传动精度。二齿差变位内齿轮行星减速机构采用对称双行星齿轮,既能平衡惯性力,又能提高机构的承载能力,具有结构简单,单级减速比大,制作成本低、传动平稳、传动精度高和传动效率高等优点。     

钢/塑齿轮组合行星传动系统的振动与噪声特性(英文)

为了深入了解钢质行星齿轮传动系统引入塑料齿轮后的振动和噪声特性,建立了钢/塑齿轮组合行星传动的动力学分析模型和实验模型,对4钢/塑齿轮组合行星传动系统的振动与噪声特性进行了理论分析与试验研究,分析了组合方式对行星传动振动特性的影响.数值仿真与实验研究结果表明:塑料齿轮的引入对行星齿轮传动的振动特性影响很大,显著地减小了太阳轮与行星轮和内齿圈与行星轮的啮合动载荷;有效地抑制了行星齿轮传动的齿轮啮合频带振动和高频带振动;组合方式对行星齿轮传动的振动特性影响显著,合理地采用钢/塑齿轮组合行星传动结构可以极大地降低啮合动载荷,从而有效地抑制了传动系统的振动和噪声.研究成果对降低工程机械中传动系统的振动和噪声具有一定的应用价值.     

丝绒织机行星式割刀机构原理分析

本文讨论了三种丝绒织机上割绒机构。用解析法,借助计算机对其中一种行星齿轮割刀传动机构进行了运动分析。并讨论了行星齿轮割刀传动机构在割刀过程一定的条件下最大的割绒门幅。     

引入塑料行星轮对行星齿轮传动动态特性的影响

为了深入了解钢质行星齿轮传动系统引入塑料行星轮后的动态特性,建立了钢/塑齿轮组合行星传动的动力学分析模型和实验模型,对含塑料行星轮行星齿轮传动系统的动态特性进行了理论分析与实验研究,分析了塑料行星轮的引入对行星齿轮传动动态特性的影响。数值仿真与实验研究结果表明:塑料行星轮的引入对轮齿动态特性影响很大,显著地减小了太阳轮—行星轮和内齿圈—行星轮的啮合动载荷;显著地降低了行星齿轮传动系统的转子不平衡工频及其谐波振动、齿轮啮合振动及其谐波振动和高频带振动;在很大程度上降低了行星齿轮传动系统的振动强度。     

行星齿轮机构传动的数学模型

通过对自动变速器行星齿轮变速机构的运动和转矩传递特性的研究,提出了一种传动分析新方法。该方法基于矩阵理论建立行星排之间联结、约束和转矩传动的数学模型,构建了一个能简便利用MATLAB进行求解的途径。通过实例分析,说明方法普遍适用于复杂行星齿轮变速机构的运动与转矩计算。     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

A computer generator for randomly layered structures

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

An Index mechanism for multi-scale view in spatial databases

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-