Algorithm of Cutter Machining Position during Numerical Controlled Last Carving

Numerical control last making machine is a machine that is used to process shoe last. A new principle of numerical control machining shoe last is put forward aiming at the deficiency of current carving last system. On the basis of the principle, the algorithm of cutter machining position during numerical controlled carving last is analyzed in detail. The complex problem of the calculation of cutter machining positiion is resolved by applying spherical milling cutter that is often used in machining free_curve surface today and taking account of practical situation of the shoe last_making machine. At the same time, the calculation of cutter machining position is realized by program using Visual C++6.0. As a result, the calculation time of cutter machining position is reduced greatly and the efficiency of design is improved. Moreover, the process of carving last is agile and precision of carving last is ensured.     

Analysis on Three -Dimensional Numerical Controlled Last Machining Algorithm

On the basis of applying three dimensional discrete formative technology to describing last surface, working principle of numerical controlled last carving machine is briefly introduced. Then the algorithm of ascertaining milling cutter machining position during the machining process is analyzed in detail. We establish a three dimensional reference frame with spatial analytic geometry and obtain the spatial equation of milling cutter rotary surface. According to last machining character, we put forward a machining algorithm named Minimal Distance Method and is used to calculate the milling cutter machining position. Finally, the glabrous degree of last made by us has reached the conventional demand.     

Research on Machining Last by Numerical Controlled Last Carving Machine

System structure of last CAD/CAM is described. Then machining principle of system output device named numerical controlled Last Carving machine is introduced. Furthermore, we lay stress on analyzing machining programming method making use of direct numeric definition. Special disposal is taken on step error and working frequency of step motors so that not only error accumulation is avoided but also step motors always work in the best frequency range. As a result, machining precision and speed of last are both enhanced as well as step motors' working safety is guaranteed.     

A new determination method of tool step for 5 axis NC machining

The peculiar non linear error in the 5 axis NC machining is studied. An improved tool step determination method for the 5 axis NC machining is proposed, in which the non linear error is compensated. Both the arc chord error and the non linear error are considered when computing the tool step, and the comprehensive error is taken as the function of the tool path parameter. Due to the difficulty of gaining the derivative of this function and the tool step according to the prescribed tolerance, the secant method is improved to guarantee the real solution locating in the converging range which is adopted to compute the tool step. The implementing example shows that the proposed method can compensate the non linear error effectively with meeting the prescribed tolerance. The exact tool step can be gotten efficiently with the improved secant method.     

Worm wheel grinding method of convex pitch line non-circular gear

To overcome the precision machining difficulty of non-circular gear, a convex pitch curve of non-circular gear and worm grinding method is presented. Firstly, worm wheel is reduced to rack cutter and a rack machining convex pitch curves of non-circular gears sport model is set up. Then based on the structure of CNC worm wheel grinding machine tools and machining principle, electronic gear box of machine tools is designed and active and following axes are planned. At the mean time, the synchronous coefficient of machine tools between synchronization is deduced by machining principle of equal arc-length, and interaction models of grinding are established. At last, the worm wheel manual presetting cutter methods with non-circular gear are given and worm grinding wheel mounting angle, axial position and axial location parameter can be adjusted along the gear.     

New Method of Machining Internal Spiral Groove of a Big Lift Angle

There exists muchinterference in machining internal spiral groove with big lift angle and small size, whichis a difficult problem. The design and calculation of tool section is analyzed in this paper while differentcutters are utilized to machine the groove when the tool axis is parallel or skew to that of the work piece. The approximating method of using circular-arc cutter is put forward, which is proved by the calculation and analysis to be a feasible method within range of the permissible error. The digital simulation of machining internal spiral groove which is finished by different methods, such as simulation of tool path, error analysis, verification of the cutter design and so on, has been done through typical software such as the Program files function of I-DEAS and the Manufacturing Module of UG.     

基于RS与GIS技术的安徽省林火监测研究

森林火灾是当今世界发生面广、危害性大、时效性强、处置救助困难的自然灾害之一。安徽省森林资源丰富,由于自然或人为原因导致的火灾经常发生。本文基于RS和GIS技术对安徽省林火监测进行研究,设计和开发相应的安徽省林火监测系统进行分析、处理并结合基础地理信息数据确定火点及其周边环境信息,根据土地利用数据判定火点中心点所在的土地利用类型,利用GIS空间分析功能快速定位,通过互联网或其它通讯设施实时发布林火信息给相关部门,从而可以较少的人力、物力和可行的成本,实现安徽省林火的监测。集成的监测系统对安徽省2008和2009年监测到的火点信息建立数据库,根据土地利用数据判定火点中心点所在的土地利用类型,结合时间分析着火的原因。研究成果已为安徽省林火监测业务服务。     

Site tools distribution method for machining job shop and its implementation

Aiming at site management problems of machining job shop, a site tools management method based on dynamic distribution for machining job shop is proposed. According to the method, the site dynamic distribution plan of machining tools is generated. A site tools distribution management information system is developed. The function and information models of the system are presented. With the system, dynamic distribution and recycling of machining tools and materials is realized. As a result, the inventory of machining tools is reduced, and the productivity is improved. The system has been applied in a machining job shop with satisfied result.     

Application of liquid crystal display in the field of dynamic wave display

It is a very important task that using a liquid crystal display module to replace the computer monitor and realizing the dynamic display of wave and data without dithering. The paper describes the way to process sampling data using synchronous technology, to transform data and to find unknowable coordinate. The transforming of address and the drawing of wave and the scrolling of wave are introduced. The dots link up with each other and the wave has no dithering. The dynamic wave and static parameter can coexist. The engineering application shows that the method is effective and economical.     

Untersuchungen zur Leitbündelstruktur der Ackerbohne (Vicia faba L.)

Investigations on the vessel structures of broad beans ( Vicia faba L.)
The number of vessels was observed in the fruit bearing axes of some varieties from Vicia faba Minor, Equina and Major during flowering. These investigations were also made on some F₂- progenies of crosses from minor × equina and Paucijuga × Eufaba and on some topflower plants.
The varieties of Minor and Equina had about 12 vessels on the base of the axis, these diminished to the top of the axis 3 or 4 vessels just before the last flower. The varieties of Major had 12 vessels on the base of the axis too, but these diminished faster because of the smaller number of flowers on the axis. In Paucijuga the number of vessels on the base of the axis was only 3 to 4. Plants of Paucijuga had only 2 or 3 flowers per axis.
Progenies from crosses between Minor × Equina had more vessels on the base of the axis, probably due to a heterotical inheritance. In progenies from crosses between Paucijuga × Eufaba an intermediate inheritance was found in the number of flowers per axis and in the number of vessels.
Due to the investigations on a comprehensive material it is probable that the described vessel structure exists in most broad beans. This structure is complex arranged and modifyable. With this organization it is quite unprobable that the vessel structure will be a yield reducing factor.     

Parameter Design for Machining Quenched Internal Helical Gears by EDM

Aiming at the problem of machining quenched internal helical gears, a method and its equipment are discussed and designed, which is used for machining quenched internal helical gears by EDM. Its characteristic and principle are proposed. The modifying design of the electrode gear and the calculating method of its modification coefficients is presented. Analyzing for the error of the machining equipment is done. The results show that this problem can be solved by EDM, the electrode gear is the modification gear of machined gear and the machining accuracy can be improved by controlling errors.     

The Geometric precision and Performance Analysis for machining Surface based on Fractals

A new analysis method for machining surface profile error is presented in this paper.The linear regression and nonlinear regression are first applied respectively,and then the Weierstrass Mandebrot fractal function is used to obtain the fractal parameters of machining profiles.A minimal parameter set which depicts the machining surface geometric precision is set up,and the surface profile can be reconstructed using these parameters,and an analysis method for part performance and its tolerance structure is proposed.Examples are provided to illustrate the method is feasible and effective.     

The importance analysis of tool magazine fault and its reliability improved design

The reliability level of tool magazine is an important indicator to show how advanced a horizontal machining center is. To more effectively promote the reliability level of tool magazine,a new method combining importance and structure optimization is introduced. Taking tool magazine of a horizontal machinging as object, the fault tree of a tool magazine is established based on 35 failure data obtained from a horizontal machining center. Important levels of elementary events are calculated by fault tree analysis,and the order of importance is determined based on importance values. An improved design of structural reliability for elementary events with great importance is made according to failure principles and tool changing process. The feasibility of the improved design is verified by the designer of the tool magazine.     

量子点荧光探针在食品安全检测中的应用

量子点荧光探针是近几年发展起来的一种新型荧光标记物,量子点在生命科学的应用已成为人们研究的热点。但将量子点荧光探针用于食品安全检测的研究还处于起步阶段。简要综述量子点的光学特性、制备方法及其在食品安全检测方面的研究进展和应用前景。     

On line tool breakage monitoring method based on power information and cross-correlation algorithm

In order to reliably monitor unexpected tool failure and prevent workpiece or machine tool from possible damages in batch machining, a tool breakage on-line monitoring method based on power information and cross-correlation algorithm is proposed. In this method, wavelet coefficients of spindle-power signal are used as the characteristic vector of machining information, and then the vector sequence extracted from a normal machining process via Mallat wavelet is defined as the reference template for monitoring cutting tool condition. In batch machining, real-time characteristic vector of the workpiece in machining process is extracted via an improved real-time wavelet algorithm. The correlation of two vector sub-sequences within a sampling time window, which is described by generalized cross-correlation coefficient, decreases apparently when the tool is broken. The generalized cross-correlation coefficient is defined as tool condition index (TCI), and tool breakage can be detected by monitoring the TCI with a threshold value. Experiments show that the method can accurately identify tool breakage failures in normal machining condition, and thus it is practical.     

山西中条山十八河铜尾矿库自然定居草本植物群落与环境的关系

为揭示铜尾矿库自然定居草本植物群落与环境的关系,本文在中条山矿区十八河铜尾矿库进行植物样方的基础上,采用TWINSPAN分类、DCA和CCA排序相结合的方法,对该尾矿库自然定居草本植物群落进行数量分类与排序研究。结果表明：1)TWINSPAN分类方法将51个自然定居草本植物样方划分为两大类10个群丛,一类主要是以湿生草本植物芦苇(Phragmites communis)为主的群丛,另一类主要是以中生草本植物垂柳(Salix babylonica)幼苗为主的群丛；2)DCA排序第一轴反映了草本植物群落分布与土壤水分的关系,沿第一轴从左到右,土壤水分含量逐渐降低,草本植物种类由湿生植物向中生、旱中生植物逐渐过渡；DCA排序第二轴反映了植被生活型的变化,沿第二轴由下到上,自然定居草本植物种类由一年生向多年生演替；3) CCA排序第一轴与土壤湿度和土壤电导率有关,反映了是群落由湿生植物→中生植物和耐盐性植物；第二轴与物种丰富度等指数有关。     

山西省终霜冻变化及其与春季北太平洋海温的SVD分析

摘 要：利用山西省35个代表站1971-2008年逐年终霜冻资料和美国NCEP/NCAR再分析资料的全球逐月海温格点(2°×2°)资料,采用小波分析、EOF和SVD分解等方法讨论了山西省终霜冻的时空变化特征以及与北太平洋海温的关系。结果表明：山西省终霜冻时空分布不均匀,存在显著的年际和年代际变化特征。山西省终霜冻有提前的趋势。山西省终霜冻异常存在3年、5年、15年的周期;影响终霜冻的春季海温关键区是（20°S~35°N,110~160°E ）,山西省春霜冻与该关键区春季海温是显著的负相关关系,即春季海温关键区海温异常偏高（低）,山西省终霜冻偏早（晚）。     

Constant Scallop-height tool-path Planning for Surface Interpolation and the Evaluation of Errors

The calculative precision of the cutting breadth has a significant effect on the machining precision and the machining efficiency for free-form surface machining. For traditional arithmetic, there are two oppositional approaches to calculate the path interval. One approach is very simple, but its veracity is not enough for complex surface. The other approach is very complicated, so its calculative efficiency is low. A new approach is presented to calculate the path interval. A spline of circle is adopted to approach the transversal of surface. Then the arithmetic based on the spline is proposed to calculate the path interval. In the proposed methodology, the calculative efficiency is fully improved on the condition of meeting the need of machining precision. Furthermore, the algorithm''s time needed by calculating path interval is steady. So it is suitable for periodic interpolation. Two study cases verify the applicability of this new approach of Constant Scallop-height tool-path planning.     

Parallel Computing in NC Machining Program

This paper presents a method which is based on MPI and uses idle distributed computation resource to speed up NC machining program. The experimental results of cutter-location data parallel computation algorithm based on projection method and adaptive projection method show that it scores satisfying speedup.     

OPTIMUM ARC APPROXIMATION OF COMPLEX PLANE CURVES

Arc approximation method is widely used in machining those parts contoured by various complex plane curves. In this paper, several arc approximation methods are reviewed, and the algorithm of the optimum arc approximation, which ensures the continuity of derivatives, is established. The algorithm presented can be used to precisely machine the parts with complex plane curves and the revolving body with a curved surace. In addition, it can also be used in part-programming of CNC machining.