一种新的自动调焦方法—离轴探测法

本文提出了的种新的自动调焦方法——离轴探测法,此法没用任何附加元件,结构简单、装调容易、线性度好、灵敏度高、调焦范围大、实用性强;介绍了此法的原理、理论计算结果及实验结果;给出了应用实例.     

C_0复杂度的改进及其在证券市场中的应用

系统地分析了Lemple-Ziv复杂性度量方法的应用过程中,将实际信号(时间序列)转变成符号序列的诸多方法中存在的一些问题,提出了更合理兼容法.该方法可以有效地刻划各种时间序列的复杂度.文章最后动态地分析了中国证券市场的复杂性.     

The structure of dehydrated zeolite 3A (Si/Al = 1.01) by neutron profile refinement

A neutron powder diffraction study of a dehydrated commercially available potassium exchanged zeolite A (Linde 3A) has shown that the diffraction pattern can be indexed in cubic space group $\text{Fm}\text{3}\text{c}$. For this sample there is 63% exchange of potassium for sodium (K⁺/Na⁺ = 1.69). Data collected at a neutron wavelength of 2.98 Å shows no evidence of rhombohedral distortion and suggests that the assignment of space group $\text{Fm}\text{3}\text{c}$ is correct. The final structural model is closely analogous to that found for dehydrated sodium zeolite A (J. M. Adams, D. A. Haselden, and A. W. Hewat, J. Solid State Chem.44, 245 (1982); J. J. Pluth and J. V. Smith, J. Amer. Chem. Soc.102, 4074 (1980). Unusual features of previous refinements of potassium containing zeolite A samples, i.e., “zero coordinate” cations (P. C. W. Leung, M. B. Kunz, K. Seff, and I. E. Maxwell, J. Phys. Chem.83, 741 (1979)) or potassium inside the β-cage (J. J. Pluth and J. V. Smith, J. Phys. Chem.83, 741 (1979)) have not been found. Refinements using the same 1.9 Å neutron powder diffraction data were also obtained with the models of Leung et al. and Pluth and Smith (1979) as starting points (denoted LKSM and PS, respectively) and comparison is made with these. The final R factors for the three refinements were R_pw (A. K. Cheetham and J. C. Taylor, J. Solid State Chem.21, 253 (1977)) = 10.24% for the model presented here, R_pw = 10.38% (PS model), and R_pw = 10.61% (LKSM model).     

Peak alignment of urine NMR spectra using fuzzy warping

Proton nuclear magnetic resonance (1H NMR) spectroscopic analysis of mixtures has been used extensively for a variety of applications ranging from the analysis of plant extracts, wine, and food to the evaluation of toxicity in animals. For example, NMR analysis of urine samples has been used extensively for biomarker discovery and, more simply, for the construction of classification models of toxicity, disease, and biochemical phenotype. However, NMR spectra of complex mixtures typically show unwanted local peak shifts caused by matrix and instrument variability, which must be compensated for prior to statistical analysis and interpretation of the data. One approach is to align the spectral peaks across the data set. An efficient and fast warping algorithm is required as the signals typically contain ca. 32,000-64,000 data points and there can be several thousand spectra in a data set. As demonstrated in our study, the iterative fuzzy warping algorithm fulfills these requirements and can be used on-line for an alignment of the NMR spectra. Correlation coefficients between the aligned and target spectra are used as the evaluation function for the algorithm, and its performance is compared with those of other published warping methods.     

Estimating rate constants in a convection-diffusion system with a boundary reaction

While performing biomolecular interaction analysis (BIA), scientistsoften use surface plasmon resonance (SPR) to measure rate constantsof the associated reactions. A mathematical model of a BIAcore^TM,a common SPR device, consists of a convection-diffusion equationin a channel with a reacting surface at the channel ceiling.Asymptotic and singular perturbation techniques are used toanalyse the concentration of the reacting species in two cases:when the reaction occurs much more slowly than diffusion, andwhen the reaction occurs on the same time-scale as diffusion.Linear and nonlinear integral equations result from the analysis;explicit and asymptotic solutions are constructed for physicallyrealizable cases. These expressions provide a direct way toestimate the rate constants from raw data.     

交通流非参数回归模型

交通流宏观参数流量、速度和占有率在交通工程和管理中具有非常重要的作用 ,对这三者关系的刻划反映了道路本身特性和交通流的规律。到目前为止 ,基本上采用线性或非线性的参数模型来描述 ,此类模型在应用中具有一定的局限性 ,并交通变量时间序列进行预测 ,数据拟合表明 ,选择适当的核函数或邻近数以及窗宽 ,可以达到比较满意的效果     

离子交换色谱法分离测定磷霉素的研究

分别采用全多孔型硅胶基键合强阴离子交换柱与氨丙基键合硅胶柱,在低波长 ２００ ｎｍ 处检测,分离测定了磷霉素 探讨了流动相条件,如ｐ Ｈ 值、离子强度等对磷霉素保留及分离选择性的影响,优化分离条件,建立了一种测定磷霉素的高效液相色谱新方法方法简便、快速     

对-叔丁基杯[8]芳烃键合硅胶制备及其毛细管电色谱性能研究

以γ-(环氧丙氧)丙基键合硅胶为前体,于硅胶表面键合环氧基,在催化剂存在下以杯芳烃钠盐开环制备杯芳烃键合硅胶固定相.该方法反应条件温和,适用性强.将这个新方法首次用于制备对-叔丁基杯[8]芳烃电色谱键合固定相(C8BS),采用加压电色谱初步评价其电色谱性能.研究结果表明,C8BS电渗流(Electrosmoticflow,EOF)较小,但通过控制键合反应及使用压力辅助电色谱可部分弥补上述不足.该固定相的EOF受流动相pH影响小(pH=3-8),同时大环配体屏蔽效应能有效地克服硅羟基引起的碱性化合物拖尾现象,这对电色谱分离具有重要意义.通过分步封尾研究EOF的来源发现,杯芳烃酚羟基对EOF有弱的贡献,这与报道的杯芳烃涂层具有径向电渗流调控能力相一致.     

蒙药新-Ⅱ中微量硒的测定

采用硒 -硫氰酸钾 -罗丹明 B-明胶 - OP体系分光光度法测定蒙药新 - 中微量硒。其含量为 6 .6—7.3μg· g-1 ,回收率为 94 %— 95 %。