A deep convolutional neural network is employed to simultaneously measure the beam-pointing and phase difference of sub-beams from a single far-field interference fringe for coherent beam combining systems.The amplitu...A deep convolutional neural network is employed to simultaneously measure the beam-pointing and phase difference of sub-beams from a single far-field interference fringe for coherent beam combining systems.The amplitudes of sub-beams in the measurement path are modulated in order to prevent measuring mistakes caused by the symmetry of beam-pointing.This method is able to measure beam-pointing and phase difference with an RMS accuracy of about 0.2μrad andλ/250,respectively,in a two-beam coherent beam combining system.展开更多
在干扰信号相干的情况下,一般波束形成方法不能准确地对相干信号和期望信号进行到达角(DOA)估计,干扰抑制效果较差。通过对相干信号和加权矢量二次型性能函数的分析,提出了一种相干干扰抑制方法,即基于多约束最小均方(multiple constrai...在干扰信号相干的情况下,一般波束形成方法不能准确地对相干信号和期望信号进行到达角(DOA)估计,干扰抑制效果较差。通过对相干信号和加权矢量二次型性能函数的分析,提出了一种相干干扰抑制方法,即基于多约束最小均方(multiple constrained least mean square,MC-LMS)算法的空域调零抗干扰技术。该方法利用MC-LMS算法迭代计算权值,并对阵列信号自适应加权输出,通过频谱分析可以得到抑制干扰的效果。计算机仿真和工程实现表明该方法在复杂的电磁环境下能对相干干扰进行抑制,并通过抗干扰的数量和抗干扰性能验证了该方法的有效性。展开更多
Objective:To investigate the relationship between growth patterns and mandibular posterior tooth-alveolar bone complex morphology in a Chinese population with normal occlusion.Methods:Forty-five patients with normal o...Objective:To investigate the relationship between growth patterns and mandibular posterior tooth-alveolar bone complex morphology in a Chinese population with normal occlusion.Methods:Forty-five patients with normal occlusion(23 males,22 females) were included in this study.Among these patients,20 displayed the vertical growth pattern,and 20 had the horizontal growth pattern,while the remaining patients displayed the average growth pattern.All of the patients underwent dental cone beam computed tomography(CBCT),which included the region of the mandibular posterior teeth and the alveolar.A linear regression analysis and a correlation analysis between the facial height index(FHI) and the alveolar bone morphology were performed.Results:The inclination of the molars,the thickness of the cortical bone,and the height of the mandibular bone differed significantly between patients with the horizontal growth pattern and those with the vertical growth pattern(P<0.05).Significant positive correlations were found between:the FHI and the inclination of the molars;the FHI and the thickness of the cortical bone;and the FHI and the height of the mandibular bone.Conclusions:The mandibular posterior tooth-alveolar bone complex morphology may be affected by growth patterns.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.61775223 and11974367)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB1603)。
文摘A deep convolutional neural network is employed to simultaneously measure the beam-pointing and phase difference of sub-beams from a single far-field interference fringe for coherent beam combining systems.The amplitudes of sub-beams in the measurement path are modulated in order to prevent measuring mistakes caused by the symmetry of beam-pointing.This method is able to measure beam-pointing and phase difference with an RMS accuracy of about 0.2μrad andλ/250,respectively,in a two-beam coherent beam combining system.
文摘在干扰信号相干的情况下,一般波束形成方法不能准确地对相干信号和期望信号进行到达角(DOA)估计,干扰抑制效果较差。通过对相干信号和加权矢量二次型性能函数的分析,提出了一种相干干扰抑制方法,即基于多约束最小均方(multiple constrained least mean square,MC-LMS)算法的空域调零抗干扰技术。该方法利用MC-LMS算法迭代计算权值,并对阵列信号自适应加权输出,通过频谱分析可以得到抑制干扰的效果。计算机仿真和工程实现表明该方法在复杂的电磁环境下能对相干干扰进行抑制,并通过抗干扰的数量和抗干扰性能验证了该方法的有效性。
基金Project supported by the Shandong Science and Technology Planning Project (Nos.2010G0020232,2010HM053,and 2010GSF10269)the Shandong Provincial Natural Science Foundation (No.ZR2012HM087)+1 种基金the Jinan Science and Technology Planning Project(No.JN201202042)the Shandong University Project(Nos.2011JC009 and 2012JC031),China
文摘Objective:To investigate the relationship between growth patterns and mandibular posterior tooth-alveolar bone complex morphology in a Chinese population with normal occlusion.Methods:Forty-five patients with normal occlusion(23 males,22 females) were included in this study.Among these patients,20 displayed the vertical growth pattern,and 20 had the horizontal growth pattern,while the remaining patients displayed the average growth pattern.All of the patients underwent dental cone beam computed tomography(CBCT),which included the region of the mandibular posterior teeth and the alveolar.A linear regression analysis and a correlation analysis between the facial height index(FHI) and the alveolar bone morphology were performed.Results:The inclination of the molars,the thickness of the cortical bone,and the height of the mandibular bone differed significantly between patients with the horizontal growth pattern and those with the vertical growth pattern(P<0.05).Significant positive correlations were found between:the FHI and the inclination of the molars;the FHI and the thickness of the cortical bone;and the FHI and the height of the mandibular bone.Conclusions:The mandibular posterior tooth-alveolar bone complex morphology may be affected by growth patterns.
