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双语推荐：椭圆度

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提出结合主元变换与异方差变量含误差模型的椭圆识别与定位方法。根据椭圆长轴对应于椭圆主元方向的特点,利用主元变换法将目标边缘数据变换到主元坐标系,给出新的椭圆轮廓度误差评定方法,将变换后数据点集的椭圆轮廓度误差作为椭圆识别的依据,采用基于异方差变量含误差模型的拟合算法获取椭圆的中心坐标。该方法将任意椭圆转化为标准型椭圆,简化了识别过程,考虑到椭圆数据点的异方差特性,提高了椭圆的定位精度,在噪声方差为0.05情况下,定位精度小于0.04 pixel。
A method of ellipse detection and location based on Principal Components Analysis(PCA)and Heteroscedastic Errors-in-Variable(HEIV)is proposed. According to the fact that major axis of an ellipse is the direction of principal com-ponents, the data points are projected on the coordinate frame of principal axis using PCA. A new evaluation method for elliptical profile error is proposed, and the ellipse objects are recognized according to the elliptical profile error of the data points after translation. An ellipse fitting method based to the HEIV model is applied to realizing the precision locating of the ellipse objects. The method simplifies the process of ellipse detection by translating arbitrary ellipse to standard one, and improves the location precision in view of the heteroscedastic performance of data points. The location precision is less than 0.04 pixel when the noise variance is 0.05.

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目的椭圆管件是最常见的圆柱管件变形状态,通常采用缩径方式矫圆,研究矫圆过程中影响塑性变形的关键参数。方法建立了椭圆柱管件正圆模型,找到了影响截面最大应力值的关键参数,即椭圆度和厚度半径比,并进行了无因次化。采用控制变量法,运用非线性有限元软件ABAQUS,模拟了不同椭圆度和厚度半径比的椭圆管件,正圆过程中的截面最大应力值。结果通过对比大量数据,得出了椭圆管正圆椭圆度和半径厚度比影响曲线以及塑性临界曲线。结论为揭示缩径矫圆机理,完善矫圆的预测提供了参考。
Objective Oval tube is the most common deformation of cylindrical tube, which is usually set round by radi-us shrinkage. The aim of this paper is to investigate the key parameters influencing the plastic deformation during the round setting process. Methods This paper established round setting model for cylindrical tube, identified the key parameters that affected the value of the maximal stress, the ovality and the thickness to radius ratio, and the model was made dimension-less. Using the variable controlling method and the nonlinear finite element software ABAQUS, oval tubes with different ovality and thickness to radius ratios were simulated, achieving the maximal stress values during the round setting process. Results By comparing large amounts of data, influencing curve of perfect circle ovality and radius to thickness ratio of the oval tube and the plastic critical curve were obtained. Conclusion The study provided reference for revealing the radius shrinkage round setting mecha

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得到了强非局域非线性介质中的形变像散椭圆呼吸子的解析解，并基于解析解讨论了这类呼吸子的演化性质。在传输过程中光束在两个维度上仍保持高斯的形状，但束宽与等相位面曲率均做两个维度上不同步的等周期演化。当光束在两个维度上均为非束腰入射时，不管功率如何，光束的汇聚或发散惯性将继续保持一段距离，继而形成二维异步同周期呼吸效应。当光束在某方向上为束腰入射时则既可能形成二维异步呼吸，也可能只有一维呼吸。束宽的二维异步呼吸还导致了椭球等相位面曲率以及光斑椭圆率的周期性变化。在二维束腰重合情况下，椭圆率的最大值和最小值总是固定的且二者之积为1；入射位置的变化不影响椭圆率最值，但会影响椭圆率变化速度在一个周期内的分布均匀性和最大椭圆率出现的位置。
The analytical solution for the shape-variant astigmatic elliptical breathers in strongly nonlocal nonlinear medium is obtained, and the propagation properties of this type of breather is investigated according to the solution. During propagation, the beam in x-and y-direction keeps Gaussian, the beam width and the curvature of the cophasal line vary periodically but asynchronously. For the two-dimensional off-waist input case, the initial convergence (divergence) makes the width narrowed (broaden) first near the entrance plane, no matter what the input power is;then varies periodically but asynchronously in x-and y-direction. For the one-dimensional on-waist input case, the beam might breathe only in one direction. The breather of the beam width induces the periodical variation of the curvature for the elliptically cophasal surface and the ellipticity of the pattern. If the location of the waist in x-direction and that in y-direction are identical with each other, the product of the m

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对山形和槽形GCr15SiMn钢环体进行了同炉真空淬火和低温回火试验，并做了畸变统计。结果表明：两种钢环体硬度均匀，为58～62 HRC；但畸变趋势不同，其中山形钢环体内外径收缩畸变量大于椭圆度变化，最大收缩畸变量为-0．44 mm；而槽形钢环体内外径涨缩畸变和椭圆度均较明显，且内外径涨缩量为-0．34～＋0．43 mm，椭圆度为0．20～0．50 mm。
The GCr15SiMn steel rings with Yamagata and grooved shapes were vacuum quenched and tempered in the same furnace, the distortion was also statisticed.The results show that the both steel rings have uniform hardness of 58-62 HRC; but the distortion trend is different, which the Yamagata steel rings diameter contraction is larger than the ovality, the maxmum contraction distortion is -0.44 mm;the inner-outer diameter distortion and ovality of the grooved steel rings are all obvious, and the inner-outer diameter distortion is -0.34-+0.43 mm, the ovality is 0.20-0.50 mm.

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针对望远镜对高精度测角技术的要求，分析了机械安装偏心、加工椭圆度误差、轴系晃动等对新型拼接式钢带光栅编码器测角的影响，并制定了相位差为90°的4读数头软件细分测角方案。在机械安装偏心为10μm、加工椭圆度为2μm、轴系晃动为0.6″的实验平台上进行了逆时针和顺时针测角实验，两组实验测角误差RMS值分别为0.393″和0.488″。实验表明：该测角方案能消除机械安装偏心、加工椭圆度误差等对测角数据的影响，实现了亚角秒级测角。
To satisfy rigid performance specifications of goniometry for a telescope , this paper analyzes the im-pacts of the mechanical installation eccentric , roundness error and the shafting sloshing on angle measurements by an encoder with a scale tape grating , and develops a software subdivision angle measurement program based on 4 reading heads and 90°phase difference.The counterclockwise and clockwise angle measuring experi-ments are performed on a experimental platform with a mechanical installation eccentric of 10 μm, roundness error of 2 μm and shafting sloshing of 0.6″.The measuring angle error RMS values from two sets of experi-ments are 0.393″, 0.488″, respectively.The experiments prove that the program can eliminate the angular measurement errors caused by the mechanical installation eccentric , machining roundness error and the shaft-ing sloshing.It achieves arcsecond angle measurements .

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采用有限体积法建立椭圆形轴承流场的数值分析模型，并运用FLUENT求解椭圆形轴承流场，分析轴承椭圆度、偏心率等参数对轴承动特性的影响，并对不同转速下椭圆形轴承的Taylor涡进行研究。结果表明：随着椭圆度的增大，整个轴承－转子系统的稳定性提高；油膜压力随着偏心率近似线性增加；随着转速的增大，湍流Taylor涡开始出现，数目逐渐增加，涡流形状逐渐由规则变为不规则。
The numerical model of the flow field of elliptical bearings was built by finite volume method.The effects of the ellipticity and eccentricity on the dynamic characteristics of the bearing film were analyzed,and the Taylor flows of dif-ferent velocities were studied by FLUENT.The results show that,with the increase of ellipticity,the stability of the bearing rotor system is improved.Oil film pressure is increased approximately linearly with the increase of eccentricity.With the in-crease of speed,the turbulent Taylor vortex appears,and the number of vortex is increased gradually,vortex changes from regular shape to irregular shape.

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超椭圆柱设计表面能够减小线圈与目标的距离，提高空间利用率，扩大成像区域的有效范围。提出利用流函数法及柱面的可展性在超椭圆柱面上设计核磁共振成像系统中的梯度线圈。根据Biot-Savart定律建立磁场强度与流函数的表达式，采用最小二乘法和Tikhonov正则化方法构造了双目标设计函数。利用柱面的可展性提高了基于分片离散流函数计算电磁场的数值精度，通过L-曲线方法实现了正则参数的合理选取。通过引入适当的流函数边界约束条件，把梯度线圈的优化问题转化为适定线性方程组的直接求解问题。通过数值算例验证了超椭圆柱面展开求解方法的正确性。优化结果显示，在满足线性度误差小于5%的设计约束下，该方法在设计超椭圆柱面线圈驱动电流分布的同时有效控制了梯度线圈的能耗。
A super-elliptical cylinder surface can shorten the distance between coils and target, enhance the space utilization, and enlarge the homogeneous imaging volumes. This paper proposes a method to design magnetic resonance imaging (MRI) gradient coils using the stream function and the developable property of the super-elliptical cylindrical surface. Based on the Biot-Savart law, the relationship between the magnetic flux density and stream function is established firstly, and the objective is chosen in the least-square form with the additional Tikhonov regularization term. Numerical accuracy of the magnetic flux density in the region of interest is maintained through transforming the cylindrical surface to the corresponding flat surface, and the value of regularization coe?cient of the dissipated powers is chosen automatically by using the L-curve method. Via imposing specified boundary conditions to the stream function on the developed surface, the optimization of gradient coi

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针对传统锻造方法加工出的锻件尺寸散差、椭圆度、锥度大的情况，设计出整径工装及模具，提高了锻件尺寸精度和材料利用率，满足轴承市场需求。
Aiming at the big dispersion error, ellipticity and conicity of the forgings produced by traditional forging method, the tooling for finishing hole and outer circle shape and die is designed. By this new method, the dimensional accuracy and stock utilization is increased so as to meet the need of bearing market.

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研究了J55膨胀管的壁厚误差、椭圆度、残余应力对其抗挤强度的影响。并利用ANSYS有限元对J55膨胀管实际抗挤毁过程进行了仿真模拟,结果表明:壁厚的减小降低抗挤强度,壁厚的增加提高抗挤强度。随着椭圆度的增加,套管抗挤强度不断地减小。轴向残余拉应力使套管的抗挤强度明显降低,径向残余应力对套管抗挤强度的影响基本上呈线性规律。通过理论计算结果和模拟结果的比较,验证了模拟的合理性。
In this article, it studied the effect of J55 expansion casing wall thickness deviation, ovality and residual stress on its collapse-resistance strength. Furthermore, it utilized ANSYS FEM software to simulate the collapse-resistance process. The results showed reducing wall thickness can low collapse-resistance strength, and increasing wall thickness can enhance collapse-resistance strength. With ovality increasing, the collapse-resistance strength reduces continually. The axial residual tensile stress significantly reduces the collapse-resistance strength of expansion casing, and the influence of radial residual stress on collapse-resistance strength is basically linear. Through the comparison of theoretical calculation and simulation results, the rationality of the simulation was verified.

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连续油管在每次起下作业中经历多次弯曲—拉直塑性变形,低周疲劳失效事故时有发生。依据连续油管工作状态,设计了专用的连续油管疲劳寿命装置和试件。对60.325 mm连续油管进行了疲劳寿命实验,得到了不同循环次数下连续油管椭圆度、壁厚变化值,基于数学回归方法拟合出椭圆度及壁厚随循环次数计算公式,给出了低周疲劳寿命公式。研究结果表明,连续油管的疲劳寿命符合率达到90%,因此,采用新的计算方法能够为工程连续油管失效预测及控制提供理论依据。
The coiled tubing experiences 6 times of bend-straighten plastic deformation in each pipe lifting process, and the low-cycle fatigue failure accident occurs occasionally. Based on the work state of coiled tubing, a set of tailor-made experimental device and specimen on fatigue life was designed. The fatigue life test was carried out on the coiled tubing of ?60.325 mm. The values of ovality and wall thickness of different cycles were obtained in the experiment. The formulas of ovality and wall thickness were generated based on the mathematical regression method, and the formula of low cycle fatigue life was given. The experimental results show that the fa-tigue life calculation coincidence rate was over 90%. Therefore, the calculation method could be a theoretical basis for the coiled tubing failure prediction and control.

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