记录光强变化对光折变晶体多重存储衍射效率均匀性的影响

光折变晶体多重存储中,为获得均匀的衍射效率,要根据记录晶体的时间常数计算相继写入全息图的曝光时间,而晶体的时间常数是记录光强的幂函数.本文分析了光强变化对衍射效率的影响.结果表明,对曝光时间加以适当修正,可补偿光强变化对衍射效率均匀性的影响.     

厚度对光聚物高密度全息存储记录参量的影响

本文用实验方法研究了光致聚合物的曝光时间常量、曝光能量常量、动态范围、曝光灵敏度和折射率调制度等高密度全息存储参量随样品厚度的变化规律,结果表明随着样品厚度的增加,曝光能量常量、曝光时间常量及材料的动态范围也增加,但材料的曝光灵敏度却减小,而折射率调制度却没有明显的变化规律.     

Interaction of water with poly(vinyl methyl ether) in aqueous solution

Near-infrared, viscometric, and calorimetric measurements were made on aqueous poly(vinyl methyl ether) (PVME) solutions at temperatures between 15 and 43°C. We found a hydrogen-bonded structure of water around the polymer chain (a polymer-water complex), which is characterized by two distinct hydration numbers (i.e., 2.7 and 5.0 water molecules on each monomer unit of the chain) by analyzing the concentration dependence of endothermic enthalpies at a cloud point temperature, ca. 35°C. In particular, the 2.7 water-polymer complex has been suggested to be cooperatively formed by using data of the near-infrared (nir) absorption spectrum around 1930 nm. Furthermore, the peak-wavelength of the nir spectrum has been observed to change drastically at the cloud point when the temperature is raised. This can be interpreted as a cooperative collapse of the hydrogen-bonded water structure to free water, resulting in the aggregation of the polymer chains due to the exposure of their hydrophobic groups at the cloud point. © 1994 John Wiley & Sons, Inc.     

Progress of super-resolution near-field structure in near-field optical storage technology

Super-resolution near-field structure (Super-RENS) is one of the most promising near-field optical recording schemes with significant application prospects. The development of Super-RENS from the basic type to the third-generation is introduced. The development of mask material and the application of Super-RENS in different recording systems are summarized.     

萃取色层梯度淋洗和柱后反应光度法连续检测装置

用普通材料自制和组装一套能梯度淋洗和柱后反应光度法连续检测萃取色层柱的流出曲线的设备。详细叙述了淋洗液切换阀、六通样样阀、四通混合器、盘管反应器的制作和将国产原子吸分光光度计改装流动光度计。     

用近红外无损肌氧及运动心率检测技术评定100m极量强度运动对心脏冲击影响

利用连续双波长近红外光技术测量肌肉中血红蛋白含氧量的变化情况,同时应用运动心率无线实时采集设备,设计了检测实时肌肉组织血氧含量和瞬时心率实验方案,对6名健康男性进行了100 m跑同步实测实验。实验表明,肌肉组织氧合血红蛋白浓度在100 m跑结束后继续降低,达到最低值的时刻滞后于运动结束时刻的时间为(6.65±1.10)s;心率则在运动结束后继续上升,达到最高值的时刻滞后于运动结束时刻的时间为(8.00±1.57)s。这些结果显示了双波长近红外光组织氧测试技术和运动心率无线实时采集系统能够正确检测极量强度运动时的血氧参数和心率,揭示了极量强度运动过程中肌肉中氧运输与消耗的过程及其与心率之间的动力学特征。     

Symmetry properties of three-dimensional magnetization distributions induced by focused circularly polarized lights

We analyze symmetry properties of the three-dimensional magnetization distribution in the optic-magneto film induced by focused circularly polarized lights. The magnetization distributions are derived and evaluated based on the vector diffraction theory and the inverse Faraday effect of the isotropic and nonmagnetically ordered material. It is shown that for any radial symmetrical amplitude, phase, or hybrid amplitude-phase pupil filter, the magnetization distribution of the axial component is circular symmetric but those of the radial and azimuthal components are annular symmetric with regard to the optical axis. All of the three components have a symmetric distribution with regard to the focal plane. The direction of both axial and radial components can be inversed with the helicity of incident circularly polarized light but the direction of azimuthal component is independent of helicity. The axial component has a decisive effect to all-optical magnetic recording, and within the effective axial range, the size of its magnetization domain hardly expands in the transverse direction.     

关于混合拾音制式通项公式的探究

对混合拾音制式传声器摆放中所遵循的规律进行了深入探讨。运用心理声学手段,得到了听觉定位与声音物理参数间的定量关系,进而推导出了混合拾音制式的通项公式,并证明了现行的各种制式只是同一心理声学规律的一组特解,找到了设置拾音器摆放的通用方法,对提高录音作品的质量有一定的指导意义。     

基于可见-近红外光谱技术与BP-ANN算法的污水类型鉴定

提出了一种基于可见-近红外光谱技术与BP人工神经网络(BP-ANN)算法快速进行污水类型鉴定的新方法.以FieldSpec(R)3地物光谱仪采集了4种污水样品的光谱数据,共168份,随机将其分成校正集(132份)和检验集(36份).分别采取全波段(400～2450 nm)与择取波段(400～1800 nm)两种方法建立模型进行分析.光谱经S.Golay平滑和标准归一化(SNV)处理后,以主成分分析法(PCA)降维.将降维所得的前9个主成分数据作为BP-ANN的输入变量,污水类型作为输出变量,建立3层BP-ANN鉴别模型.利用36个未知样对模型进行检验.结果表明:两类模型预测准确率均高达100%,且择取波段模型比全波段模型具有更高的预测精度.说明利用可见-近红外技术结合BP-ANN算法进行污水类型的快速、无污染鉴定是可行的,且波段筛选是优化模型的有效方法之一.