Previously we derived equations determining line broadening in ax-ray diffraction profile due to stacking faults. Here, we will consider line broadening due to particle size and strain which are the other factors affe...Previously we derived equations determining line broadening in ax-ray diffraction profile due to stacking faults. Here, we will consider line broadening due to particle size and strain which are the other factors affecting line broadening in a diffraction profile. When line broadening in a diffraction profile is due to particle size and strain, the theoretical model of the sample under study is either a Gaussian or a Cauchy function or a combination of these functions, e.g. Voigt and Pseudovoigt functions. Although the overall nature of these functions can be determined by Mitra’s R(x) test and the Pearson and Hartley x?test, details of a predicted model will be lacking. Development of a mathematical model to predict various parameters before embarking upon the actual experiment would enable correction of significant sources of error prior to calculations. Therefore, in this study, predictors of integral width, Fourier Transform, Second and Fourth Moment and Fourth Cumulant of samples represented by Gauss, Cauchy, Voigt and Pseudovoigt functions have been worked out. An additional parameter, the coefficient of excess, which is the ratio of the Fourth Moment to three times the square of the Second Moment, has been proposed. For a Gaussian profile the coefficient of excess is one, whereas for Cauchy distributions, it is a function of the lattice variable. This parameter can also be used for determining the type of distribution present in aggregates of distorted crystallites. Programs used to define the crystal structure of materials need to take this parameter into consideration.展开更多
该文设计了一款可用于第四代（4G）移动通信的宽带偶极子天线。利用寄生微带线的阻抗加载,实现不平衡-平衡转换的巴伦;设计天线臂与巴伦之间的传输线,使其在阻抗匹配的同时能延展天线臂中辐射电流径程,产生新的谐振点,实现带宽扩展。2-3...该文设计了一款可用于第四代（4G）移动通信的宽带偶极子天线。利用寄生微带线的阻抗加载,实现不平衡-平衡转换的巴伦;设计天线臂与巴伦之间的传输线,使其在阻抗匹配的同时能延展天线臂中辐射电流径程,产生新的谐振点,实现带宽扩展。2-3 GHz频带内仿真和实测回波损耗（S11）吻合较好,小于-10 d B频带覆盖4G的6个业务频段,频带内仿真和实测方向图也显著体现了偶极子天线良好的辐射特性。展开更多
文摘Previously we derived equations determining line broadening in ax-ray diffraction profile due to stacking faults. Here, we will consider line broadening due to particle size and strain which are the other factors affecting line broadening in a diffraction profile. When line broadening in a diffraction profile is due to particle size and strain, the theoretical model of the sample under study is either a Gaussian or a Cauchy function or a combination of these functions, e.g. Voigt and Pseudovoigt functions. Although the overall nature of these functions can be determined by Mitra’s R(x) test and the Pearson and Hartley x?test, details of a predicted model will be lacking. Development of a mathematical model to predict various parameters before embarking upon the actual experiment would enable correction of significant sources of error prior to calculations. Therefore, in this study, predictors of integral width, Fourier Transform, Second and Fourth Moment and Fourth Cumulant of samples represented by Gauss, Cauchy, Voigt and Pseudovoigt functions have been worked out. An additional parameter, the coefficient of excess, which is the ratio of the Fourth Moment to three times the square of the Second Moment, has been proposed. For a Gaussian profile the coefficient of excess is one, whereas for Cauchy distributions, it is a function of the lattice variable. This parameter can also be used for determining the type of distribution present in aggregates of distorted crystallites. Programs used to define the crystal structure of materials need to take this parameter into consideration.
文摘该文设计了一款可用于第四代（4G）移动通信的宽带偶极子天线。利用寄生微带线的阻抗加载,实现不平衡-平衡转换的巴伦;设计天线臂与巴伦之间的传输线,使其在阻抗匹配的同时能延展天线臂中辐射电流径程,产生新的谐振点,实现带宽扩展。2-3 GHz频带内仿真和实测回波损耗（S11）吻合较好,小于-10 d B频带覆盖4G的6个业务频段,频带内仿真和实测方向图也显著体现了偶极子天线良好的辐射特性。
