机加零件中“假废品”现象探讨

结合轴类零件的加工过程,分析了零件加工过程中“假废品”产生的原因,提出了判定假废品的方法,对降低制造成本,保证零件加工精度具有一定的实用价值。     

假废品现象的研究

对假废品现象进行了定性和定理分析,提出了产生似废品现象的原因,如何通过现有的设备和正常加工方法获得较高加工精度要求的设计尺寸。     

零件加工过程中基于尺寸链计算的“假废品”分析

在零件加工过程中,当工艺基准与设计基准不重合时,必须经过尺寸链计算,按换算后的工序尺寸进行加工或测量时,就会产生"假废品"的现象.通过实例分析"假废品"现象及其产生的原因,给出"假废品"公差带的确定方法,并提出了如何判定与处理"假废品"的相应措施.     

机械加工过程中减少假废品的措施

对于机械零件加工过程中常出现的假废品现象进行了较为细致的分析,提出了判别和减少假废品的方和措施,对于保证加工精度、降低成本有一定实用价值。     

试论装配精度与切削加工经济性的关系

按照零件机械加工出现的废品期望损失最小 ,调整机床刀具位置 ,使加工零件尺寸分布既保证装配精度 ,又使加工成本最低     

五轴机床加工零件轮廓误差预测方法

研究了五轴机床进给轴实际位置预测方法和零件轮廓误差求解方法,在此基础上提出了五轴机床加工零件轮廓误差预测方法。机床进给轴实际位置的预测,通过辨识选定机床进给轴传递函数和读取待加工零件插补指令、将各轴指令输入各轴传递函数获得。零件轮廓误差的求解,通过正运动学变换求解工件坐标系下待加工零件的指令位置轨迹和实际位置轨迹、求解二者之间的轮廓误差来实现。以S形试件为加工零件,以科德KMC600SUMT五轴铣车立式复合加工中心为加工机床,预测了S缘条直纹面A的轮廓误差。刀尖位置误差和刀轴姿态误差引起的零件轮廓误差随着直纹面的位置变化,误差分别在0.04mm和±7×10-5 rad内。研究结果表明:建立的五轴机床加工零件轮廓误差预测方法,可以在加工前实现零件轮廓误差的精确预估,提前判断选定机床是否能够满足零件轮廓误差的要求,为优化加工参数、保证高速加工下的零件轮廓精度提供依据。     

薄壁零件加工装夹方法及加工技巧分析

薄壁零件是目前工业生产当中具有较多应用的零件类型,在实际加工当中具有较为复杂的特点,如果没有做好处理,即可能发生变形等问题而对零件的品质与精度产生影响。为了在不同切削力下也能够保障加工的稳定性,需要能够以最大切削用量的方式做好装夹力的确定。而为了对零件在精度方面的要去进行满足,当具有较大材料切除量、且零件在精度方面具有较高要求时,则可以对粗加工-精加工的路线进行使用。     

“假废品”的判别方法探讨

“假废品”现象在实际生产申经常出现，本文介绍“假废品”的判别方法。     

浅析普通机床加工薄壁零件的方法

普通机床加工高精度薄壁零件,在机械加工企业中历来是个技术难题,在生产中易产生疵品、废品。针对这一现象,本研究在分析普通机床加工薄壁零件的传统工艺的基础上,通过改进加工方法、设计专用夹具提高加工薄壁零件的生产效率和加工质量。     

试析机械加工对精度加工制造造成的影响

近年来我国社会经济不断地发展,这对我国的机械制造业带来许多有利的影响,尤其是在零件加工方面,众所周知,零件的加工是机械设备的重要部分,但是在实际的加工中,它会受到各种因素影响,从而导致其精度产生一定的误差或者是位置发生一些偏移等,这就导致零件的尺寸、形状都难以满足机械的实际需要。该文主要分析机械加工精度的影响因素,然后提出一些改进方法。     

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