基于非圆曲线的数控车削宏程序开发及应用

针对数控系统常规手工编程中难以加工非圆曲线的不足,以FANUC数控系统中椭圆曲线的车削加工为研究对象,采用分析归纳法开发出非圆曲线的通用宏程序,并给出该宏程序在椭圆和抛物线曲面零件加工中的编程应用。加工实践表明：该宏程序适用于所有非圆方程曲线的加工,灵活简便,通用性强,有效提高了编程的效率和质量。     

非圆车削中刀具运动实现方法

为了分析非圆车削过程中切削速度和刀具工作角度变化对工件加工质量和刀具使用寿命的影响,建立了非圆车削切削速度和刀具工作角度的数学模型。以椭圆截面活塞和盘形凸轮零件的车削为例,定量分析了刀具工作角度随零件非圆截面周向位置变化的规律。结果表明:非圆车削刀具运动形式取决于零件非圆截面径向尺寸变化范围。提出了非圆车削中的刀具复合运动及其实现方法,设计了一种具有径向往复移动和摆动的刀具驱动机构,适于车削凸轮等零件,可保证最佳的刀具工作状态。     

非圆车削高频响应进给系统的结构设计与分析

基于非圆切削对径向进给系统的要求,选用直线伺服电机直接驱动方式,进行非圆切削数控车床径向进给系统的结构设计,分析了刀架和工作平台两个关键结构件的力学性能,并通过活塞环、椭圆和正六边形3个特殊非圆截面零件车削时的速度和加速度特性试验,对设计的进给系统进行了切削性能分析.结果表明,设计的数控车床径向进给系统具有较高的频率响应特性,满足非圆截面零件高速车削加工的要求.     

FANUC Oi数控系统车削二次曲线零件宏程序的应用

在数控车削加工中,由于现代的数控系统中只有直线插补和圆弧插补指令,不适合二次曲线类零件的编程,因此二次类零件的加工是比较困难的,本文较全面总结了FANUC Oi数控系统车削加工二次类零件中宏程序的应用.采用切槽法使二次曲线的宏程序编程更加简便.     

利用自动编程实现抛物线曲面在数控车床上的加工

数控车床一般只能作直线插补和圆弧插补，遇到回转轮廓是抛物线等非圆曲线的零件时，数学处理的任务是用直线段或圆弧段去逼近非圆轮廓。解决的方法主要有宏指令编程及软件自动编程，针对GSK980T系统采用宏指令编程较难实现，本文则通过利用CAXA数控车自动编程软件及相关通讯软件实现了抛物线曲面在GSK980T系统数控车床上的车削加工，保证了工件的加工精度和生产效率。     

单片机机床数控系统设计

针对CH3240-MC液压伺服转塔车床,研制了一种单片机的数控系统.介绍了系统的硬件构成,G代码编程和LCD液晶显示条件下的系统软件设计.研究了G代码编程实现不同加工要求时,对机床工作台进给速度和定位控制.实际使用表明,该数控系统可实现加工程序,通用G代码编程;在工作台和液压伺服系统的配合下,能很好地满足零件加工工艺的要求.     

FANUC 0i数控系统车削二次曲线零件宏程序的应用

在数控车削加工中,由于现代的数控系统中只有直线插补和圆弧插补指令,不适合二次曲线类零件的编程,因此二次类零件的加工是比较困难的,本文较全面总结了FANUC 0i数控系统车削加工二次类零件中宏程序的应用。采用切槽法使二次曲线的宏程序编程更加简便。     

基于宏程序的非圆曲线轮廓数控车床加工

随着科学技术的发展和工业产品外观设计的不断提高,数控车削加工中经常有由一些复杂曲线构成的非圆曲线工件,而数控编程中没有相应的指令,需要采用拟合法与宏指令进行编程.该文介绍基于FANUC 0i Mate TC数控系统,用宏程序来实现非圆曲线工件加工的程序编写方法.     

B类宏程序在灯罩模具内曲面加工中的应用探讨

模具行业的发展从根本上说代表着某个国家在该领域的总体水平,它与数控机床的有机结合将是未来的必然趋势。机械加工中常有由复杂曲线所构成的非圆曲线零件的模具产品,此类零件在数控加工中属于轮廓形状较复杂之列。一般的数控系统只有直线和圆弧插补指令,而没有非圆曲线插补指令,为了提高此类产品的加工效率和质量,本论文中提出了一种使用宏程序编程的方法,探讨通过宏程序控制指令在加工灯罩模具内曲面中的具体应用,解决了实际应用问题。     

非圆柱体车削的进给运动分析

分析了车削非圆柱体径向进给运动的振动特性、速度特性、加速度特性。论述在满足这些特性的前提下如何提高工件转速和加工质量,以及非圆截面柱体零件的设计、加工工艺的制定、设备的选择等方面应注意的问题。     

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.     

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.     

A computer generator for randomly layered structures

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

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.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

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.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with