铁基形状记忆合金防松螺母重复使用性能研究

为了降低铁基形状记忆合金防松螺母的使用成本,探索了该新型螺母重复使用的可行性。使用M10螺母进行试验测试,螺母在不同回复退火温度间隔条件下的自锁摩擦力矩均有所增大,温度低于573K时,自锁摩擦力矩增加量均小于25%,当回复退火温度间隔为50K时,自锁摩擦力矩增加量有4次在25%以上,该新型螺母重复使用性能较好。     

输电塔横担螺栓铝合金防松垫片的防松性能研究与改进设计

轴向拉压载荷以及横向剪切载荷是输电塔横担螺栓连接结构的主要受力形式.针对输电塔横担螺栓连接结构在风载作用下发生松动的现象,提出一种使用铝合金两面凹凸垫圈自锁双螺母的组合防松螺栓.对不同的防松螺栓垫圈进行风动激励研究,研究工况分别为使用不同形状垫圈和自锁双螺母的组合防松螺栓,分析不同组合防松螺栓的防松性能,提出组合载荷作...     

航空发动机转子螺栓连接预紧力散差分析

螺栓连接预紧力的一致性对于保障航空发动机转子的安全运行有重要作用.该文针对航空发动机转子零部件的法兰止口典型连接结构的螺栓紧固控制问题,提出了含收口自锁力矩的扭拉关系修正模型,分析了收口自锁力矩衰减引入的偏差项的影响;并设计了工艺差异条件,搭建模拟试验环境开展了试验研究.结果 表明:收口自锁力矩会因收口螺母的重复使用而...     

预应力碳板楔紧式锚具数值模拟和试验

设计了用于工程结构加固的预应力碳纤维增强复合材料(CFRP)板(碳板)楔紧式锚具,该锚具由锚杯、夹片组成,通过自锚夹持碳板。基于ANSYS软件建立了锚具的精细化有限元模型,该模型同时考虑了夹片与碳板及夹片与锚杯之间的接触。基于有限元的计算结果,进行了预应力碳板楔紧式锚具的制作和试验,试验结果表明该锚具能够可靠地锚固碳板。通过将有限元结果和试验结果进行对比,发现有限元模型能够较好地预测楔紧式锚具的受力性能,能够为预应力碳板楔紧式锚具的设计提供参考。     

工装设计上的涨紧典型结构简析

本文介绍了应用在工装设计领域的典型涨紧结构以及对一些涨紧结构的涨紧原理的简单分析。对涨紧的技术条件,自锁性做了比较详细的推算。在涨紧力方面,侧重对螺纹的校核,并进行了必要的计算。     

提高双螺母并紧效果的方法分析

双螺母也在人类的生活中不断繁衍壮大,就是这么一个小小的东西,如果不处理好,可能会导致火车出轨,煞车失灵等等一系列严重问题。因此,提高双螺母并紧效果是非常重要的,研究提高双螺母并紧效果这一原理也是非常有必要的。     

螺母锁丝孔加工结构性改进刍议

螺母类零件为机械行业中最常见的紧固件类零件之一,六角形螺母零件由于装配要求,外六方结构常带有锁丝孔,这种孔的加工通常在夹具上直接加工或在六方面上先划窝后钻孔,但是容易造成毛刺大、效率低、尺寸控制困难等问题,本文从六角零件保险孔的技术标准入手,改变以往的加工方法,对锁丝孔的加工进行了结构性的改进,设计了结构简单又便捷的钻工艺孔夹具,锁丝孔的加工准确、快捷,相关尺寸均有理论依据,锁丝孔毛刺小、加工效率高、合格率高,零件总体质量得到大幅度提高,也为锁丝孔的加工开辟一条新的思路。     

摩擦接触约束下的非刚性装配动态卡阻楔紧分析

在装配系统的整体运动规律及弹性接触变形条件下,对装配系统进行了近刚性接触分析.在库仑摩擦模型及单面接触约束模型的基础上建立装配系统的柔顺动力学模型,根据方程系统中系数矩阵的奇异性来分析相应的卡阻、楔紧现象,得出顺利装配的无卡阻运行空间以及随着设备承载能力的增大和材料弹性的增强,楔紧的发生几率减小的规律.     

一种材料和结构设计的新概念

根据拓扑自锁原理介绍了一种新的复合材料和结构设计的概念，无须使用粘结材料，来形成一种具有设计所要求性能的材料或结构。研究证明：按照这样的概念，利用不同几何形状的小“构件”(包括以平面形成的四面体，以及以曲面形成的立体)均能形成具有良好性能的层状自锁结构。主要以四面体形成的自锁结构为例，讨论了这种自锁结构的力学性能和自锁机理。     

基于QFD和TRIZ的产品创新设计理论模型及应用

采用QFD技术解决顾客需求,结合TRIZ理论解决顾客需求与设计要求之间的冲突.将两种理论有机的结合起来,提出以QFD、TRIZ理论及市场评价为基础建立产品创新设计的模型.运用该模型可实现结构化的产品创新设计过程,克服制约因素的阻碍作用,使产品能迅速投入市场,并提高产品创新的成功率.通过自锁螺母收口机床设计的工程实例,说明以QFD的质量屋为基础、以TRIZ理论为解决工具,对产品创新设计的支持.     

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