带传动效率的研究

本文分析了带传动(主要是三角带传动)中引起功率损失的各个因素; 论述了影响工业上常用的几种三角带及该种三角带传动效率的主要因素; 指明了提高其传动效率的途经; 推荐了较佳应用条件。文末给出实例,它说明更高效率的带传动能节省很多的能源和开支。     

平板传动带节能

许多事例表明,由三角带传动改成平板传动带传动,可以达到显著的节能效果。与齿轮传动相比,平板带传动效率可高达98％,而三角带的平均效率为86％。某公司生产的60匹马力真空泵,由三角带改为平板带,据称单单电费一项,该泵一年则可节约近1200美元。     

三角带传动的计算机辅助设计

本文在分析传统的三角带传动设计方法的基础上,提出了一个计算机辅助设计的新方法及通用软件系统,文中采用了1980年ISO/TC_(41)颁布的三角带承载能力计算新标准ISO5292—1980的计算公式。并采用优化设计的方法,按照实际工作的要求,在使得三角带传动的性能指标获得最佳的条件下选取各参数。设计计算完毕后,即可自动进行带轮的结构设计并绘制出带轮的零件工作图。这样大大加快了设计速度,减少了设计人员的劳动强度,使得三角带传动的设计达到了一个新的水平。     

三角带传动的模糊可靠性优化设计

运用可靠性理论及模糊数学基本知识，建立了三角带传动的模糊可靠性优化设计的数学模型，并结合实例进行了优化设计。     

C语言在三角带传动中的应用

主要是利用C语言进行三角带传动程序的设计。     

三角带传动承载能力最大的模糊优化设计

在三角带传动设计中 ,带长、带轮直径、带速、带轮包角等参数的影响因素多具有模糊性 ,为了对其模糊性进行定量分析 ,将常规约束条件改造为模糊约束条件 ,将模糊优化原理与方法应用于三角带传动设计 ,建立了以承载能力最大为目标的模糊优化设计数学模型。对数学模型的求解采用迭代解法 ,其中常规优化方法采用复合形法。实例计算表明 ,该方法是一种更科学、更符合客观实际的设计方法。     

三角带传动承载能力最大的模糊优化设计

在三角带传动设计中,带长、带轮直径、带速、带轮包角等参数的影响因素多具有模糊性,为了对其模糊性进行定量分析,将常规约束条件改造为模糊约束条件,将模糊优化原理与方法应用于三角带传动设计,建立了以承载能力最大为目标的模糊优化设计数学模型。对数学模型的求解采用迭代解法,其中常规优化方法采用复合形法。实例计算表明,该方法是一种更科学、更符合客观实际的设计方法。     

三角带传动专家系统

本文论述了三角带传动专家系统的设计思想和功能,阐述了该系统在微型计算机上用Prolog语言实现的方法,并扼要介绍了对一些特殊问题的处理与编程技术。     

对ISO5292—1980(E)工业三角带传动额定功率计算公式的探讨

本文借助于幕函数展开成麦克劳林级数,再以近似计算的方法,对1962年ISO建议的普通三角带额定功率计算公式进行变换,取得与1980年ISO规定的工业三角带传动额定功率计算公式完全一致的形式。本文对两种方法进行分析和对比.我们认为ISO5292计算公式更合理,因此建议早日采用。     

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。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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