Research of mechanical stresses in irradiated tin-doped silicon crystals

An optical method of registration of mechanical stresses in undoped and tin-doped silicon samples is offered. Influence of electron irradiation on energy 5 MeV and high-temperature treatment at a 723 K on residual stresses in a silicon lattice was analyzed in the paper. The proposed method is based on а modulation of polarization of laser radiation transmitted through the anisotropic area and the definition of its anisotropy parameters by means of this modulation. The modulation polarimetry technique is an express method with high detection and resolution. The method allows identifying residual stresses in samples in absolute units with a resolution of 1·10⁻⁴ MPa.     

基于一般散射模型的Hybrid Freeman/Eigenvalue分解算法

提出了一种新的基于一般散射模型的hybrid Freeman/eigenvalue分解算法,用于分析极化合成孔径雷达(PolSAR)数据.文中,单位矩阵作为体散射模型,相干矩阵的两个较大特征值对应的特征向量作为表面散射模型和二次散射模型,并且不需要反射对称条件.新算法有三个优点:第一,表面散射和二次散射不需要反射对称条件,更符合一般散射体的建模;第二,因为散射能量是相干矩阵特征值的线性组合,所以散射能量具有旋转不变性;第三,表面散射能量和二次散射能量避免了负值现象.在San Francisco地区的AIRSAR数据上进行了实验,证明了新算法的有效性.     

SAR imaging using multidimensional continuous wavelet transform and applications to polarimetry and interferometry

Usual SAR imaging process makes the assumption that the reflectors are isotropic and white (i.e., they behave in the same way regardless the angle from which they are viewed and the emitted frequency within the bandwidth). The multidimensional continuous wavelet transform (CWT) in radar imaging was initially developed to highlight the image degradations due to these assumptions. In this article the wavelet transform method is widened to polarimetry and interferometry fields. The wavelet tool is first used for polarimetric image enhancement, then for coherence optimization in interferometry. This optimization by wavelets, compared with the polarimetric one, gives better results on the coherence level. Finally, a combination of both methods is proposed. © 2005 Wiley Periodicals Inc. Int J Imaging Syst Technol, 14, 206–212, 2004; Published online in Wiley Inter‐Science (www.interscience.wiley.com). DOI 10.1002/ima.20025     

化学拆分法制备D-2-氨基丁醇

以酒石酸为拆分剂,从外消旋2-氨基丁醇中拆分出（ D）-2-氨基丁醇和（ L）-2-氨基丁醇。考察了不同的溶剂对2-氨基丁醇拆分的影响,最终选取了正丁醇作为拆分溶剂。并对反应时间,反应温度,溶剂体积对拆分的影响进行了考察。在最优条件下, D-2-氨基丁醇的总收率达到83.69％,旋光达到9.9°。     

Enhancement of confocal microscopy images using Mueller-matrix polarimetry

A simplified procedure based on Mueller-matrix polarimetry has recently been reported as a method of retinal image improvement in a confocal ophthalmoscope [J. M. Bueno et al ., J. Opt. Soc. Am. A 24, 1337 (2007)]. Here, we have applied the technique to imaging static samples providing well-defined reflection properties. The method uses a generator of polarization states in the illumination pathway of a confocal scanning laser system. From the calculated four elements of the Mueller matrix of any sample and instrument combination, the best images defined by different metrics were constructed. For samples with specular, diffuse and mixed reflections, the best-constructed images showed an enhancement in both objective and subjective image quality compared to the original images and those obtained from frame averaging. This technique could improve microscopic imaging in many diverse fields, particularly in biomedical imaging.     

Polarimetric Borehole Radar System for Fracture Measurement

Radar polarimetry is a technology that overcomes the limitation between the radar resolution and the penetration depth of borehole radar. We have developed a stepped-frequency polarimetric borehole radar system. This is a polarimetric borehole radar system which measures the full-radar polarimetry in a borehole by changing the antenna arrangements. By using a network analyzer and an optical analog signal link, this system has a frequency bandwidth of 2–500MHz, which is suitable for two different antennas for radar polarimetry. We also propose a technique for polarimetric antenna calibration. In order to understand the potential of polarimetric borehole radar, field measurement were carried out at the Mirror Lake fractured-rock research site (NH, USA). The radar penetration depth from the borehole in the reflection measurement was over 10m, at the frequency range of 2–402MHz. We observed many clear reflections from fractures in each polarization status. Even in the raw data, we found the differences in the radar profile for different polarization status. We believe the polarimetric feature is closely related to the roughness of each fracture, and it is also related to the physical properties of the fracture such as water permeability.     

近红外旋光法检测食糖的蔗糖分

目的 建立一种近红外旋光法测定食糖的蔗糖分。方法 通过配制纯蔗糖溶液,确定在589.44 nm（589 nm）和880.00 nm（880 nm）波长下蔗糖溶液酸水解前后旋光度差值的比值,基于普通旋光法（国家标准）推导出近红外旋光法计算蔗糖分公式,并将测定结果进行比对。结果 在589 nm和880 nm波长下蔗糖溶液酸水解前后旋光度差值的比值为2.333,在蔗糖分为50%~100%时,近红外旋光法线性关系良好,回收率为98.9%~100.1%,相对标准偏差为0.043%~0.064%,与普通旋光法比对结果一致。结论 该方法灵敏、准确,具有良好的重复性和稳定性,应用范围广,可用于食糖的蔗糖分检测。     

葡萄糖酸钠检测方法研究

本文介绍了四种常用的葡萄糖酸钠检测方法：HPLC法、分光光度法、非水滴定法和旋光法。其中HPLC法和非水滴定法较方便且有较好的实用性，可以用于葡萄糖酸钠的工业生产中。     

葡萄糖酸钠检测方法研究

介绍了4种常用的葡萄糖酸钠检测方法：HPLC法、分光光度法、非水滴定法和旋光法。其中HPLC法和非水滴定法简便且具有较好的实用性，可用于检测工业生产的葡萄糖酸钠。