In this paper, we have studied several classes of planar piecewise Hamiltonian systems with three zones separated by two parallel straight lines. Firstly, we give the maximal number of limit cycles in these classes of...In this paper, we have studied several classes of planar piecewise Hamiltonian systems with three zones separated by two parallel straight lines. Firstly, we give the maximal number of limit cycles in these classes of systems with a center in two zones and without equilibrium points in the other zone (or with a center in one zone and without equilibrium points in the other zones). In addition, we also give examples to illustrate that it can reach the maximal number.展开更多
In this paper, we first give the concept of m-degree center-connecting line in n-dimensional Euclidean space Enand investigate its several properties, then we obtain the length of m-degree center-connecting line formu...In this paper, we first give the concept of m-degree center-connecting line in n-dimensional Euclidean space Enand investigate its several properties, then we obtain the length of m-degree center-connecting line formula in finite points set. As its application,we extend the Leibniz formula and length of medians formula in n-dimensional simplex to polytope.展开更多
It is illustrated that there exists an inflection circle on the linkage rigid body by the principle of relative motion. Confirmed methods of the inflection circle, curvature radius and curvature center of the point tr...It is illustrated that there exists an inflection circle on the linkage rigid body by the principle of relative motion. Confirmed methods of the inflection circle, curvature radius and curvature center of the point track on the linkage rigid body are given in the case of the different contact type of move instantaneous center line and static instantaneous center line. The regularity of distribution of curvature radius and curvature center of the point track is researched. The identification methods called determination parameters and auxiliary vertical line of the diameter and direction of the inflection circle in the four bar mechanism are pointed out. A design method of the crane hoisting mechanism is discussed in the end of this paper.展开更多
目的:探讨牙列缺失种植修复患者石膏模型中多植体空间位置信息的建立方法,为比较不同方法获取的植体空间位置信息奠定基础。方法:选取6名8个牙列缺失种植固定修复患者,通过开窗夹板式聚醚橡胶制取印模,灌制石膏模型。通过模型扫描仪扫...目的:探讨牙列缺失种植修复患者石膏模型中多植体空间位置信息的建立方法,为比较不同方法获取的植体空间位置信息奠定基础。方法:选取6名8个牙列缺失种植固定修复患者,通过开窗夹板式聚醚橡胶制取印模,灌制石膏模型。通过模型扫描仪扫描石膏模型,输出三角网格数据(stereolithography,STL)作为参考模型数据库。探讨在Geomagic Control X软件中,确定单个植体和多颗植体的空间位置信息的可行性。结果:在Geomagic Control X软件的同一坐标系下,建立了单个和多颗植体的修复基台平面、中心线、中心点,并用这3个参数完成了石膏扫描数据与牙列缺失患者术后CBCT多颗植体的空间位置比较。结论:在Geomagic Control X软件可以获取多植体的空间位置信息,实现比较植体三维空间的位置偏差和角度偏差,本研究为比较多颗植体空间位置信息比对奠定了一定基础。展开更多
文摘In this paper, we have studied several classes of planar piecewise Hamiltonian systems with three zones separated by two parallel straight lines. Firstly, we give the maximal number of limit cycles in these classes of systems with a center in two zones and without equilibrium points in the other zone (or with a center in one zone and without equilibrium points in the other zones). In addition, we also give examples to illustrate that it can reach the maximal number.
基金Supported by the Department of Education Science Research Project of Hunan Province(09C470)
文摘In this paper, we first give the concept of m-degree center-connecting line in n-dimensional Euclidean space Enand investigate its several properties, then we obtain the length of m-degree center-connecting line formula in finite points set. As its application,we extend the Leibniz formula and length of medians formula in n-dimensional simplex to polytope.
文摘It is illustrated that there exists an inflection circle on the linkage rigid body by the principle of relative motion. Confirmed methods of the inflection circle, curvature radius and curvature center of the point track on the linkage rigid body are given in the case of the different contact type of move instantaneous center line and static instantaneous center line. The regularity of distribution of curvature radius and curvature center of the point track is researched. The identification methods called determination parameters and auxiliary vertical line of the diameter and direction of the inflection circle in the four bar mechanism are pointed out. A design method of the crane hoisting mechanism is discussed in the end of this paper.
文摘目的:探讨牙列缺失种植修复患者石膏模型中多植体空间位置信息的建立方法,为比较不同方法获取的植体空间位置信息奠定基础。方法:选取6名8个牙列缺失种植固定修复患者,通过开窗夹板式聚醚橡胶制取印模,灌制石膏模型。通过模型扫描仪扫描石膏模型,输出三角网格数据(stereolithography,STL)作为参考模型数据库。探讨在Geomagic Control X软件中,确定单个植体和多颗植体的空间位置信息的可行性。结果:在Geomagic Control X软件的同一坐标系下,建立了单个和多颗植体的修复基台平面、中心线、中心点,并用这3个参数完成了石膏扫描数据与牙列缺失患者术后CBCT多颗植体的空间位置比较。结论:在Geomagic Control X软件可以获取多植体的空间位置信息,实现比较植体三维空间的位置偏差和角度偏差,本研究为比较多颗植体空间位置信息比对奠定了一定基础。
