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°。     

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.     

基于商空间粒度的极化SAR图像分类

当前极化合成孔径雷达(SAR)图像的分类研究中,极化信息的不完全利用是影响极化SAR图像分类效果的重要原因之一。故将商空间粒度合成理论引入到极化SAR图像分类中,通过建立不同的支持向量机(SVM)分类器构建不同的商空间,从多个粒度层面实现对极化信息的综合利用。首先通过不同的极化分解方法得到不同的极化特征,分别对其建立不同的支持向量机分类器进行分类;再根据粒度合成理论对这些商空间进行融合,得到更细粒度上的改进的分类结果。最后,利用AIRSAR图像进行实验比较,算法改进后的结果在地物误分上有明显的抑制,各类别分类正确率都有所提高。     

Impact of edge localized mode on photo-elastic-modulator based motional Stark effect polarimetry

Intermittent increase in background light induced by edge localized mode (ELM) in high confinement mode (H-mode) plasma gives disturbances to polarization angle of incident light measured by motional Stark effect (MSE) polarimeter using photo-elastic modulator (PEM), even if the background light is not polarized. The error in the polarization angle γ_PEM determined by the light intensity at the frequency modulated by the PEM originates in a broadband frequency spectrum of the intermittent background light and applies to PEM based polarimeter in general. The impact of the background light induced by the ELM on the error in γ_PEM is numerically investigated in terms of the polarization angle of incident light γ, the peak intensity of background light normalized by the intensity of beam emission X_ELM, ELM frequency f_ELM, ELM decay time τ_ELM and the time constant of low-pass filter (LPF) per single stage τ_LPF. The error increases almost proportionally with γ between ±22.5° when inphase spectral amplitude is used in γ_PEM calculation. The error becomes quite large for γ approaching to the direction of PEM axis (±22.5°), when absolute spectral amplitude is used. The error increases with X_ELM but does not depend on τ_ELM. When the ELM frequency is sufficiently lower than a critical ELM frequency that is given by inverse of an effective LPF time constant (τ_LPF times the number of LPF stages), the error has its peak, the height of which is independent of f_ELM, soon after the ELM and vanishes between subsequent ELMs. However, when f_ELM is higher than the critical ELM frequency, errors induced by subsequent ELMs pile up and the error increases with f_ELM. In case of no pileup, the maximum error becomes larger for smaller τ_LPF, because impact of ELM temporally concentrates in a shorter period just after the ELM. The error induced by ELMs is roughly estimated to be ∼0.002° in a type-I ELMy H-mode JT-60U discharge, which is much smaller than other errors coming from calibrations (about 0.1-0.2°) and temporal fluctuation (less than about 0.05°), mainly since the background light induced by ELMs is weak compared to the beam emission X_ELM ∼0.07 in JT-60U. However, MSE diagnostics experiencing large background light (X_ELM) should take this kind of error into account.     

Hard X-ray polarimetry by means of Rayleigh scattering

A new linear polarimetry technique based on Rayleigh scattering is introduced. Its properties are compared to the Compton technique. Experimental verification was realized using a 5×5 segmented planar HPGe pixel detector. In the proof-of-principle experiment a measurement of Rayleigh scattering off lead atoms was performed for linearly polarized photons at two scattering angles.     

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。     

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。     

A sensitivity analysis of dual-polarization features to damage due to the 2016 Central-Italy earthquake

ABSTRACT

In this study, the sensitivity of dual-polarization features extracted from dual-polarimetric coherent synthetic aperture radar (SAR) imagery to urban damage due to the earthquake occurred in Central -Italy in 2016 is addressed. First, a conventional single-polarization feature, based on the coherence between pre- and post-event co-polarized imagery, is analysed using SAR scenes collected by the Copernicus Sentinel-1 mission over the area of Amatrice, an Italian city significantly damaged by the 2016 earthquake that affected Central Italy. Then, the same analysis is undertaken using the cross-polarized channel to point out that the joint use of co- and cross-polarized channels can help in better observing the damaged area. Finally, a coherent dual-polarimetric feature, based on the inter-channel coherence, is proposed. This feature results in a sensitivity to damaged areas comparable to the one provided by conventional single-polarization features. However, the interchannel coherence has the benefit to be based only on two SAR acquisitions, i.e. before and after the earthquake and it is less affected by false alarms. SAR, polarimetry, earthquake, losses     

基于去取向理论的全极化SAR图像模糊非监督聚类

由于复杂散射体的随机取向导致其回波具有一定的波动性,利用目标分解理论对全极化SAR图像进行分类时,分类结果会出现一定程度的错分现象。该文提出了一种新的非监督分类算法,该算法首先根据去取向理论,将目标向量旋转到最小交叉极化方向;然后,采用u/v/H参数描述散射机制,以模糊隶属函数代替参数平面的硬阈值划分;最后,以多元复Wishart分布描述相干矩阵,基于Bayes极大似然分类准则进行分类。以中国广东淡水附近的L波段NASA/JPL SIR-C全极化SAR图像作为实验数据进行了仿真试验,并进一步对聚类中心的迁移进行了讨论。试验和讨论结果表明：同基于H/和类k-mean的算法比较,该文的聚类算法对聚类效果有明显改善,类别对应的散射机制也更为准确,分类结果有利于地表类型的自动识别。     

一层非均匀随机取向非球形粒子的全极化散射

本文推导了非均匀随机取向非球形粒子散射矩阵的各个元素,得到了矢量辐射传输方程中非对角化的消光矩阵,以及相矩阵。用矢量辐射的积分方程和Mueller矩阵,计算一层非均匀随机取向非球形粒子的全极化散射,讨论了任一极化的同极化和去极化后向散射系数、极化度,VV和hh波之间的相位差,及其与各有关参数的定量的函数关系。