提出了一种基于梅尔频率倒谱系数(Mel frequency cepstrum coefficients,MFCC)的声音检测装置及算法实现。通过采集声音的波形,结合特征提取和分类算法,实现对不同声音的智能判断。从嵌入式系统硬件设计、声音波形特征提取、声音分类算...提出了一种基于梅尔频率倒谱系数(Mel frequency cepstrum coefficients,MFCC)的声音检测装置及算法实现。通过采集声音的波形,结合特征提取和分类算法,实现对不同声音的智能判断。从嵌入式系统硬件设计、声音波形特征提取、声音分类算法等方面进行了详细的研究,并对实验结果进行了分析。结果表明,该设计方案在声音检测方面具有较高的准确性和可行性。展开更多
Direct growth of GaN films on Si(001) substrate at low temperatures (620～720℃) by electron cyclotron resonance (ECR) microwave plasma enhanced metalorganic chemical vapor deposition (PEMOCVD).The crystalline phase s...Direct growth of GaN films on Si(001) substrate at low temperatures (620～720℃) by electron cyclotron resonance (ECR) microwave plasma enhanced metalorganic chemical vapor deposition (PEMOCVD).The crystalline phase structures of the films are investigated.The results of high resolution transmission electron microscopy (HRTEM) and X ray diffraction (XRD) indicate that high c axis oriented crystalline wurtzite GaN is grown on Si(001) but there is an amorphous layer formed naturally at GaN/Si interface.Both faces of the amorphous layer are flat and sharp,and the thickness of the layer is 2nm approximately cross the interface.The analysis supports that β GaN phase is not formed owing to the N x Si y amorphous layer induced by the reaction between N and Si during the initial nucleation stage.The results of XRD and atomic force microscopy (AFM) indicate that the conditions of substrate surface cleaned in situ by hydrogen plasma,GaN initial nucleation and subsequent growth are very important for the crystalline quality of GaN films.展开更多
文摘提出了一种基于梅尔频率倒谱系数(Mel frequency cepstrum coefficients,MFCC)的声音检测装置及算法实现。通过采集声音的波形,结合特征提取和分类算法,实现对不同声音的智能判断。从嵌入式系统硬件设计、声音波形特征提取、声音分类算法等方面进行了详细的研究,并对实验结果进行了分析。结果表明,该设计方案在声音检测方面具有较高的准确性和可行性。
文摘Direct growth of GaN films on Si(001) substrate at low temperatures (620～720℃) by electron cyclotron resonance (ECR) microwave plasma enhanced metalorganic chemical vapor deposition (PEMOCVD).The crystalline phase structures of the films are investigated.The results of high resolution transmission electron microscopy (HRTEM) and X ray diffraction (XRD) indicate that high c axis oriented crystalline wurtzite GaN is grown on Si(001) but there is an amorphous layer formed naturally at GaN/Si interface.Both faces of the amorphous layer are flat and sharp,and the thickness of the layer is 2nm approximately cross the interface.The analysis supports that β GaN phase is not formed owing to the N x Si y amorphous layer induced by the reaction between N and Si during the initial nucleation stage.The results of XRD and atomic force microscopy (AFM) indicate that the conditions of substrate surface cleaned in situ by hydrogen plasma,GaN initial nucleation and subsequent growth are very important for the crystalline quality of GaN films.
