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全息声压外推是Patch近场声全息技术的关键步骤.本文提出了全息声压的加权范数外推方法,该方法首先通过实测声压数据的功率谱信息构造频域加权范数,然后通过极小化频域加权范数实现全息声压外推.由于外推过程中同时利用了声压信号的波数域带宽和波数谱形状信息,因此其外推结果优于传统带限外推方法.数值仿真结果表明,该方法无论在外推精度还是计算效率上都明显优于经典的全息声压波数域外推方法.刚性箱体上的声激励固支板声压外推实验进一步验证了该方法的有效性和实用性.
关键词:
近场声全息
全息声压外推
加权范数 相似文献
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Quantitative structure–activity relationship (QSAR) studies were conducted on an in-house database of cytochrome P450 enzyme 1A2 inhibitors using the comparative molecular field analysis (CoMFA), comparative molecular similarity analysis (CoMSIA) and hologram QSAR (HQSAR) approaches. The database consisted of 36 active molecules featuring varied core structures. The model based on the naphthalene substructure alignment incorporating 19 molecules yielded the best model with a CoMFA cross validation value q2 of 0.667 and a Pearson correlation coefficient r2 of 0.976; a CoMSIA q2 value of 0.616 and r2 value of 0.985; and a HQSAR q2 value of 0.652 and r2 value of 0.917. A second model incorporating 34 molecules aligned using the benzene substructure yielded an acceptable CoMFA model with q2 value of 0.5 and r2 value of 0.991. Depending on the core structure of the molecule under consideration, new CYP1A2 inhibitors will be designed based on the results from these models. 相似文献
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This paper is devoted to the study of the photochemical processes occurring during hologram formation in a biopolymer, agar doped by chromium(VI). The evolution of both the absorbing chromium species and the polymer allowed elucidating the reactions taking place during irradiation in conditions representative of hologram formation. As previously observed with dichromated poly(vinyl alcohol) (PVA), polymer containing hydroxyl groups as agar, irradiation of dichromated agar provoked a two step reduction of chromium species and the crosslinking of the host polymer. But agar has a rather complex chemical structure and the photoproducts formed along the polymeric chains throughout the photoredox process were different in agar and in PVA. The photostability of the matrix, that has been proven, coupled with the possibility to record good quality holograms, allowed us to propose dichromated agar as a new natural photosensitive biomaterial. 相似文献
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描述用单光束激光复活制银盐白光显示反射全息图的技术,本技术的关键:1)母全息图的颜色必须恢复到满足其布拉格条件;2)复制所用的光波与记录母全息图时的参考的相同;(3)复制所用的激光采用平行偏振,以减少界面反射;94)采用白糖溶液作为折射率匹配液,取得极佳效果。 相似文献
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A novel multiple information encryption by user-image-based gyrator transform hologram is proposed. In encryption process, each channel of the user image is phase encoded, modulated by random phase function and then gyrator transformed to get the gyrator spectrum of user image. Subsequently, each channel of the secret image is normalized, phase encoded, multiplied by modulated user image, and then gyrator transformed to obtain the gyrator spectrum of secret image. The encrypted digital hologram is recorded by the interference between the gyrator spectrum of user image and the spherical wave function. Similarly, the digital hologram for decryption is recorded by the interference between the gyrator spectrum of secret image and the spherical wave function. The multiple encrypted digital holograms are multiplexed into a final encoded hologram and the corresponding digital holograms for decryption are multiplexed into a final hologram for decryption. The wavelength and radius of the spherical wave function, and angle of gyrator transform are all essential keys for decryption. The proposed system has two main features. First, the encrypted hologram has no information about secret image. Second, the hologram for decryption used as identification key. Consequently the two marked security layers of information protection are achieved. The proposal can be realized by optoelectronic system. Numerical simulation results demonstrate the feasibility and security of the proposed technique. 相似文献
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余弦二值编码纯相位全息图的数字微镜器件显示 总被引:1,自引:0,他引:1
分析了采用错误减算法的迭代过程,在已知物波函数傅里叶谱的振幅和物波函数振幅的情况下恢复出纯相位的物波函数,最大限度地保留物波的振幅及相位信息.提出采用余弦二值编码生成二值全息图,即全息图的透射率函数取0或1.二值全息图通过数字微镜器件全息显示系统进行了重构显示,重构效果很好.理论分析了数字微镜器件的衍射效率,表明其最大衍射效率仅和微镜之间的间隔尺寸与微镜边长之比有关.余弦二值编码方法从理论上消除了零级衍射,可以制作像素较多的全息图. 相似文献