矩形管双焦点不对称翻领成型器曲面研究

研究了矩形管双焦点不对称翻领成型器领口交接曲线和曲面的形成,建立了矩形管双焦点不对称翻领成型器的肩曲面及其边界曲线的数学模型,给出了其高度与其它参数的关系式,为矩形管双焦点不对称翻领成型器的CAD/CAM提供了数学理论依据.     

圆形管截面全锥面翻领成型器及其数学模型研究

提出了全锥面翻领成型器的基本思想,分析了其优缺点,并对其数学模型进行了详细研究,包括领口交接曲线、肩曲面、边界曲线。在计算机上对所建模型进行了Pro/E三维仿真验证。为正确设计圆形管全锥面翻领成型器提供理论依据。     

翻领成型器计算机辅助设计

介绍了根据翻领成型器的数学模型,在计算机上进行三维模型设计的方法.主要介绍了如何用Pro/ENGINGEERING软件,根据翻领成型器的参数来生成曲线、曲面最后到三维实体模型的技术过程.     

圆形料管翻领成型器曲面的成形过程研究

从一个新的视角研究了圆形料管翻领成型器的曲面的成型.由平张薄膜在翻领成型器外表面的运动特性,给出了流线的定义并建立了圆形料管翻领成型器的流线数学模型,以及在此基础上提出了影响翻领成型器曲面成形过程中的两个重要参数:和.然后运用Pro/Engineer软件,建立了圆形料管翻领成型器的曲面在成形过程中的任意状态下的三维曲面数字模型.     

正八边形立管截面翻领成型器设计方法

研究了正八边形翻领成型器的领口交接折线和边界折线的形成,从理论上建立了以直线代替曲线,使翻领曲面转化为平面的以直代曲的设计方法,并推导了正八边形翻领成型器的数学模型,给正八边形翻领成型器的CAD/CAM制造及手工制作提供了理论依据。     

基于逆向工程的翻领成型器设计

:利用逆向工程技术对具有复杂曲面的翻领成型器进行了设计,采用三维激光扫描设备和逆向工程软件,经过数据预处理、曲面重构等过程,得到翻领成型器产品的初步结构模型,然后把得到的三维模型导入三维造型软件中,进行相关的结构再设计,为翻领成型器提供了一种新的设计思路.     

圆形偏置翻领成型器的研究

研究了用于立式制袋-充填-封口机的圆形偏置翻领成型器.提出了用两个传统圆形截面翻领成型器进行组合的制作方法,并给出了圆形偏置翻领成型器的交接曲线及边界曲线方程,建立了数学模型.为圆形偏置翻领成型器的加工制作提供了理论依据.     

翻领制袋成型器交接曲线的偏移及制作

根据翻领制袋成型器三维数学模型,进一步推导建立了立管和肩曲面组合时的偏移交线的三维和二维的数学模型.对于现在制袋充填包装机生产企业中广泛采用的成型器制造工艺,提供了下料的理论依据.提出了使用定位套管来对焊接前的肩曲面进行定位和检测的方法.     

基于MATLAB的翻领成型器领口曲线的展开及可视化

为使翻领成型器领口曲线的设计更精确、简便,并直观地反映出设计参数之间、设计参数与结果之间的关系及设计效果.根据翻领成型器领口曲线的数学模型,介绍利用MATLAB编程作展开的方法,并对中间待选参数的数据关系、展开曲线的平面图形及领口曲线的立体图形作可视化处理并予以直接显示.结果表明,MATLAB为翻领成型器领口曲线的展开设计及加工提供了快捷有效的途径,同时也为MATLAB用于包装机械的设计提供了一个很好的范例.     

无领翼式翻领制袋成型器的研究

研究了包装机械中最新使用的新型无领翼式翻领制袋成型器的数学模型,推导出其空间领口交接曲线以及平面展开领口交接曲线的数学模型,并得出了新型无领翼式翻领制袋成型器数学模型参数间的关系,为新型无领翼式翻领制袋成型器的生产制造研究提供了数学依据.     

Dual Critical Points and Related Phenomena in Simple Fluids from the Perspective of (Approximate) Renormalization Theory

It is known that some single component fluids can have coexisting low-density and high-density liquid phases with two, separate, gas–liquid and liquid–liquid, critical points. Such behavior is found both by experiments and in recent molecular-dynamics simulations performed for certain simple isotropic attractive pair potentials with softened repulsive cores. In the present investigation, a global renormalization group theory that was employed previously to make predictions for simple Lennard–Jones and square-well fluids over wide ranges of density and temperature, including the critical point, in reasonably good agreement with molecular dynamics and Monte Carlo simulations, is applied to simple shoulder potentials and to square-well potentials with softened repulsive cores. Results using this renormalization approach are compared with some previously reported results for a shoulder potential and expectations regarding dual critical points for water.     

Closed trajectories in planar relay feedback systems

A planar system of piecewise linear differential equations with a line of discontinuity, ?₂–symmetry and a linear part having negative determinant is investigated. Using the theory of differential inclusions and an appropriate Poincaré map a complete analysis is provided. This analysis applies to uniqueness and non-uniqueness for the initial value problem, stability of stationary points, sliding motion solutions, number and stability of periodic trajectories and existence of pairs of heteroclinic trajectories connecting two saddle points forming heteroclinic cycles. A complete bifurcation diagram is given.     

产品设计中的形态相关性研究

为解决产品设计中形态的相关与协调问题,采用几何变换的方法,提出处理此类问题的一种观点.并从量化和可控性的角度入手,提供了解决形态协调性的有效途径.     

Three-dimensional symmetric shapes are discriminated more efficiently than asymmetric ones

Objects with bilateral symmetry, such as faces, animal shapes, and many man-made objects, play an important role in everyday vision. Because they occur frequently, it is reasonable to conjecture that the brain may be specialized for symmetric objects. We investigated whether the human visual system processes three-dimensional (3D) symmetric objects more efficiently than asymmetric ones. Human subjects, having learned a symmetric wire object, discriminated which of two distorted copies of the learned object was more similar to the learned one. The distortion was achieved by adding 3D Gaussian positional perturbations at the vertices of the wire object. In the asymmetric condition, the perturbation was independent from one vertex to the next. In the symmetric condition, independent perturbations were added to only half of the object; perturbations on the other half retained the symmetry of the object. We found that subjects' thresholds were higher in the symmetric condition. However, since the perturbation in the symmetric condition was correlated, a stimulus image provided less information in the symmetric condition. Taking this in to consideration, an ideal-observer analysis revealed that subjects were actually more efficient at discriminating symmetric objects. This reversal in interpretation underscores the importance of ideal-observer analysis. A completely opposite, and wrong, conclusion would have been drawn from analyzing only human discrimination thresholds. Given the same amount of information, the visual system is actually better able to discriminate symmetric objects than asymmetric ones.     

基于纵向对称面重合的机身位姿求解方法

研究了一种基于机身纵向对称面重合的机身对接位姿求解方法。该方法结合机身结构和装配工艺,提取对接交点孔和沿对称面对称的关键特征,进行机身对称面拟合,求取第一次位姿调整向量。在对称面重合的基础上,借鉴“极大-极小”原则,为各对接交点孔分配权值,建立机身位姿求解鞍点规划模型并进行求解。通过中后机身对接的实测数据分析验证了该方法的可行性。     

四次有理Bézier曲线的形状调整

给出了一种基于权因子调整的四次Bézier 曲线形状控制的有效方法。推导出了曲线肩点的两种新的表达式。这两个表达式对曲线权因子的意义进行了较好的解释,很好地反应出权因子变化对曲线肩点位置的影响。基于这两个表达式,推导出了曲线肩点插值某固定点时各权因子的具体取值公式。最后,实例表明此方法能给曲线形状调整带来实用性指导。     

Imaging with two spiral diffracting elements intermediated by a pinhole

A pseudoscopic (inverted depth) image made with spiral diffracting elements intermediated by a pinhole is explained by its symmetry properties. The whole process is made under common white light illumination and allows the projection of images. The analysis of this projection demonstrates that the images of two objects pointing away longitudinally have the main features of standard pseudoscopic image points. An orthoscopic (normal depth) image has also been obtained with the breaking of the symmetry conditions.