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基于光强传输方程与SLM的快速相位恢复(英文) 被引量:7
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作者 程鸿 吕倩倩 +2 位作者 韦穗 邓会龙 高要利 《红外与激光工程》 EI CSCD 北大核心 2018年第7期287-291,共5页
基于光强传输方程(TIE)的相位恢复技术,可以通过测量一系列垂直于光轴分布的散焦强度图,直接求解得到光场的相位信息。传统的基于TIE的强度图像采集系统在获得散焦图像时需要机械移动。通过在空间光调制器(SLM)上加载透镜相位图,使其实... 基于光强传输方程(TIE)的相位恢复技术,可以通过测量一系列垂直于光轴分布的散焦强度图,直接求解得到光场的相位信息。传统的基于TIE的强度图像采集系统在获得散焦图像时需要机械移动。通过在空间光调制器(SLM)上加载透镜相位图,使其实现可编程透镜的功能,任意改变此透镜的焦距值,可以实现不同的散焦距离,从而避免采集图像过程中CCD的移动。根据不同的算法理论,设计了两种光强图像采集系统。由于日常生活中使用相机拍照时,透镜的相位调制作用不可忽略,使用SLM代替含透镜的光传播模型中透镜的作用,设计了第一种实验装置。此外,通过在4f系统的频率域位置放置SLM,设计了第二种实验装置。真实实验的结果验证了这两种方法的有效性和正确性。 展开更多
关键词 相位恢复 光强传输方程 空间光调制器
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基于奇异值分解的可分离压缩成像方法 被引量:2
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作者 张成 汪东 +3 位作者 沈川 程鸿 陈岚 韦穗 《计算机研究与发展》 EI CSCD 北大核心 2016年第12期2816-2823,共8页
可分离压缩传感可以通过一定比例的额外测量有效地解决压缩成像问题中面临的测量矩阵维数过大的瓶颈.但是现有可分离压缩传感(separable compressive sensing,SCS)方法需要2个可分离的测量矩阵都必须是行归一化后的正交随机矩阵,其显著... 可分离压缩传感可以通过一定比例的额外测量有效地解决压缩成像问题中面临的测量矩阵维数过大的瓶颈.但是现有可分离压缩传感(separable compressive sensing,SCS)方法需要2个可分离的测量矩阵都必须是行归一化后的正交随机矩阵,其显著地限制了该方法的应用范围.将奇异值分解(singular value decomposition,SVD)方法引入可分离可压缩传感测量过程,可以有效地实现测量矩阵和重建矩阵的分离:在感知阶段可以更多地考虑测量矩阵物理易于实现的性质,如Toeplitz或Circulant等确定性结构的矩阵;在重建阶段,更多地考虑测量矩阵的优化.通过引入奇异值分解对重建阶段的测量矩阵进行优化,可以有效地改善重建性能,尤其是Toeplitz或Circulant矩阵在大尺度图像的压缩重建情形.数值实验结果验证了该方法的有效性. 展开更多
关键词 压缩成像 可分离压缩传感 可分离感知矩阵 奇异值分解 确定性矩阵
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Diagnosis and clinical manifestations of subacute combined degeneration of the spinal cord: Analysis of 21 cases 被引量:3
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作者 Yanhong Shou Caifeng Li +6 位作者 Dongsheng Fan Yang Shen Jun Zhang weizhong Xiao Shuqing Zhao Jinsheng Liu wei sui 《Neural Regeneration Research》 SCIE CAS CSCD 2007年第2期112-116,共5页
BACKGROUND: Subacute combined degeneration of the spinal cord is caused by vitamin B12 deficiency and is a kind of degenerative disease owing the characteristics of nervous system diseases. In addition, different pat... BACKGROUND: Subacute combined degeneration of the spinal cord is caused by vitamin B12 deficiency and is a kind of degenerative disease owing the characteristics of nervous system diseases. In addition, different patients have variously clinical manifestations and various prognoses after vitamin B12 therapy. OBJECTIVE: To investigate and analyze diagnosis, clinical manifestations and prognosis of subacute combined degeneration of the spinal cord. DESIGN: Case analysis. SETTING: Department of Neurology, the Third Hospital of Peking University. PARTICIPANTS: A total of 21 subacute combined degeneration of the spinal cord patients including 14 males and 7 females aged from 33 to 82 years were selected from Department of Neurology, the Third Hospital of Peking University from January 1999 to December 2005. Duration from onset to final diagnosis lasted for 1.5 - 108 months. All patients had typically clinical manifestations; meanwhile, level of serum vitamin B12 was decreased and/or vitamin B12 therapy was effective. All patients provided the confirmed consent. METHODS: Clinical data of 21 subacute combined degeneration of the spinal cord patients were retrospectively analyzed, while general data and clinical characteristics were recorded at the same time. Levels of blood routine, serum vitamin B12 and homocysteine were measured at the phase of hospitalization. Normal value of serum vitamin B12 was 187 - 1 059 ng/L and normal value of serum homocysteine was 5 - 15μ mol/L. All patients received neuroelectrophysiological examination and 15 patients received MRI examinations of spinal cord. After final diagnosis, patients were given vitamin B12 therapy. And follow-up was performed to investigate the prognosis. MAIN OUTCOME MEASURES: (1) Levels of blood routine, serum vitamin B12 and homocysteine; (2) results of neuroelectrophysiological examination; (3) results of MRI examination of spinal cord; (4) prognosis. RESULTS: Clinical data of 21 patients and follow-up data of 20 patients were involved in the final analysis and 1 patient was lost because of living in the other province. (1) Clinical manifestations: All 21 patients had typically clinical manifestations. The original symptoms included numbness of lower and/or upper limbs (5 cases), unstable gait (3 cases), limb asthenia (4 cases), limb numbness combined with light asthenia (5 cases), limb numbness combined with unskillful activity (3 cases), and limb numbness combined with unstable gait (1 case). (2) Experimental results: Eight subacute combined degeneration of the spinal cord patients accompanied with mild-severe anemia and mean corpuscular volume of 13 patients were increased. Among 13 subacute combined degeneration of the spinal cord patients not administrating vitamin B12 before hospitalization, the levels of serum vitamin B12 of 2 patients were not measured but those of other patients were decreased. After vitamin B12 therapy,the levels of serum vitamin B12 of 8 patients were normal or increased. In addition, the levels of serum homocysteine of 6 patients were not measured but those of 7 patients were increased. While, the levels of homocysteine of 5 following-up patients were normal. The levels of serum vitamin B12 of 8 patients who received with vitamin B12 therapy before hospitalization were normal or increased. Among them,the levels of bomocysteine were not measured in 4 patients, those of 3 patients were increased, and that of 1 patient was normal. (3) Results of neuroelectrophysiological examination: Among all patients, 95% (20/21) patients had abnormal sensory-evoked potential, 89% (8/9) patients had abnormal motor evoked potential, 67% (10/15) patients had abnormal nerve conduction, 13% (2/15) patients had neurogenic muscle injury showed by electromyography (EMG), 70% (7/10) patients had abnormal brain-stem auditory evoked potential, and 40% (4/10) patients had abnormal visual evoked potential. (4) Results of MRI examination of spinal cord: MRI examination demonstrated that 40% (6/15) patients had spinal cord lesion, but spinal cord lesion disappeared in 2 patients during follow up. In addition, clinical manifestations of patients were improved after standard vitamin B I2 therapy. CONCLUSION: Nervous system lesion caused by vitamin B 12 deficiency is not only involved in spinal cord, also in peripheral nerve, optic nerve, auditory pathway, etc. Diagnosis of the lesion depends on clinical characteristics and level of serum vitamin BI2. Especially, neuroelectrophysiological examination, measurement of homocysteine and MRI examination of spinal cord are beneficial for diagnosis and evaluation of therapeutic effects. 展开更多
关键词 vitamin B12 deficiency spinal cord diseases DIAGNOSIS PROGNOSIS
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Association between vascular endothelial growth factor gene promoter polymorphisms and sporadic amyotrophic lateral sclerosis in a Han Chinese population Case-control study
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作者 Na Liu Nan Zhang +7 位作者 Jun Zhang Liping Wang Xiaoyan Zhang wei sui Huagang Zhang Lingsong Li Dafang Chen Dongsheng Fan 《Neural Regeneration Research》 SCIE CAS CSCD 2009年第12期1110-1115,共6页
BACKGROUND: Studies have shown that vascular endothelial growth factor (VEGF) gene polymorphisms highly correlate with sporadic amyotrophic lateral sclerosis (ALS), although this remains controversial. To date, t... BACKGROUND: Studies have shown that vascular endothelial growth factor (VEGF) gene polymorphisms highly correlate with sporadic amyotrophic lateral sclerosis (ALS), although this remains controversial. To date, the relationship between VEGF gene polymorphism and sporadic ALS in a Han Chinese population remains unclear. OBJECTIVE: To explore the relationship between sporadic ALS and VEGF gene promoter 7 locus polymorphisms in a Hart Chinese population, and to investigate whether this relationship exhibits gender differences. DESIGN, TIME AND SETTING: A case-control study regarding genetic association was performed at the Central Laboratory of Peking University Third Hospital from 2002 to 2006. PARTICIPANTS: A total of 93 patients, who were diagnosed with definite or probable ALS according to E1 Escorial-revised diagnostic criteria, were selected from the Outpatient Department of Neurology, Peking University Third Hospital from 2002 to 2006. All patients were from Hart populations, with no family history of ALS. In addition, 103 gender- and age-matched healthy volunteers were selected as controls. METHODS: Peripheral venous blood was collected, and whole blood genomic DNA was extracted. VEGF gene promoter 7 locus polymorphisms were analyzed by PCR using the fluorescent Taqman system. The relationship between VEGF gene promoter single nucleotide polymorphisms and ALS was analyzed using Logistic regression model analysis and was stratified according to gender. MAIN OUTCOME MEASURES: 7 VEGF gene promoter polymorphisms genotype distribution and allele frequencies. RESULTS: There were no significant differences in VEGF gene promoter 7 locus genotype distribution and allele frequency between case and control groups (P 〉 0.05). Stratified analysis based on gender demonstrated that female Han subjects carrying the VEGF genotype -1154AA, -2549TT, -634CC genotype were more susceptible to ALS than those carrying -1154GG, -2549CC, -634GG (VEGF-1154AA: OR= 8.9, 95%CI= 1 .0-77.3, P= 0.047; VEGF-2549TT: OR= 3.1,95% CI= 1.0-9.6, P= 0.049, VEGF-634CC: OR = 0.2, 95%CI= 0.1-0.7, P= 0.012). Moreover, in female Han populations, people carrying allele -1154A, -2549T, -634C exhibited an increased risk of ALS (VEGF -1154A: OR = 2.3, 95%CI= 1.2 4.5, P= 0.018; VEGF-2549T: OR= 3.1,95%CI= 1.4 6.9, P= 0.005; VEGF-634C: OR= 0.5, 95%CI= 0.3 0.9, P= 0.015). CONCLUSION: Results showed that VEGF 7 gene promoter polymorphisms were associated with ALS in Han Chinese women. The VEGF gene -1154A, -2549T, -634C allele and -1154AA, -2549TT, -634CC genotype could function as susceptibility genes for ALS in Han Chinese women. 展开更多
关键词 amyotrophic lateral sclerosis genetic polymorphisms vascular endothelial growth factor
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Fractional Fourier digital holography
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作者 CAO Yu-ru wei sui 《通讯和计算机(中英文版)》 2007年第5期52-56,共5页
关键词 局部傅立叶数字全息术 局部傅立叶功率谱 魏格纳分布 模糊函数
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基于亚波长光栅结构的硅基液晶器件模型研究 被引量:5
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作者 沈川 韦穗 +1 位作者 虞海秀 陶波 《光学学报》 EI CAS CSCD 北大核心 2020年第3期14-21,共8页
金(Au)亚波长光栅被溅射到经典硅基液晶(LCoS)的ITO电极上,它与薄液晶盒和底层铝电极组成复合共振波导结构,简称GLCoS。与基于液晶传播效应的LCoS截然不同,在GLCoS中,上电极的表面等离激元与光栅槽中的TM-FP (TM-Fabry Pérot)共振... 金(Au)亚波长光栅被溅射到经典硅基液晶(LCoS)的ITO电极上,它与薄液晶盒和底层铝电极组成复合共振波导结构,简称GLCoS。与基于液晶传播效应的LCoS截然不同,在GLCoS中,上电极的表面等离激元与光栅槽中的TM-FP (TM-Fabry Pérot)共振耦合,诱导一个0阶反射的相位调制;铝(Al)电极既是反射背板又与Au光栅、薄液晶盒组成波导,使共振耦合得到增强。在操控光波阵面的同时,GLCoS也作为电控器件,施加电压改变液晶的折射率,进而控制开腔FP的边缘介质条件,达到有源0~2π相位调制。实验结果表明,本文结构可用于1μm量级像素的相位空间光调制器,在高空间带宽积的全息视频显示中具有广阔的应用前景。 展开更多
关键词 光栅 全息视频显示 亚波长金属光栅 法布里-珀罗共振 硅基液晶
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