Using magnetic nanoparticles to manipulate biological objects

The use of magnetic nanoparticles （MNPs） for the manipulation of biological objects, including proteins, genes, cellular organelles, bacteria, cells, and organs, are reviewed. MNPs are popular candidates for controlling and probing biological objects with a magnetic force. In the past decade, progress in the synthesis and surface engineering of MNPs has further enhanced this popularity.     

Supramolecular Capsules from Bilayer Membrane Scission Driven by Corannulene

Self‐assembly of polyaromatic systems has proved to be a powerful technique to construct nanoscale optoelectronic materials. However, attempts to develop self‐assembled nanomaterials guided by pristine polyaromatic molecules have been limited. Here the construction of photoactive nanocapsules through the scission of an aromatic bilayer membrane driven by curved corannulene intercalation is reported. The framework of the capsule consists of the lateral array of corannulene, a buckyball fragment. The supramolecular capsules exhibit photocatalytic activity to degrade encapsulated fluorescein dye molecules under sunlight irradiation.     

Laser cleaning of 19th century Congo rattan mats

There is a growing interest by art conservators for laser cleaning of organic materials, such as wooden artworks, paper and textiles, since traditional cleaning with solvents can be a source of further decay and mechanical cleaning may be too abrasive for sensitive fibers. In this work we present a successful laser cleaning approach for 19th century rattan mats from the Brooklyn Museum collection of African Art, now part of the study collection at the Conservation Center in New York. Tests were carried out using the fundamental (1064 nm) and second harmonic (532 nm) wavelength of a Q-switched Nd:YAG laser to measure threshold values both for surface damage and color changes for different types of rattan samples. The irradiated substrates were investigated by optical microscopy, scanning electron microscopy and by UV-vis spectroscopy in order to determine the efficiency of laser cleaning and to assess possible deterioration effects that may have occurred as a result of laser irradiation. The study showed that by using the laser emission at 532 nm, a wavelength for which photon energy is below the bond dissociation level of the main cellulosic compounds and the water absorption is negligible, it is possible to select a range of laser fluences to remove the black dust layer without damaging the rattan material.     

基于大气中性点的地-气分离方法空基验证探究

偏振遥感是遥感领域的一个新兴对地观测手段,地物反射的偏振效应是偏振遥感进行观测的基础。然而,地物反射具有偏振效应,大气粒子的反射与散射也具有偏振效应,并且大气的偏振效应往往大大强于地物偏振效应。当用偏振遥感器对地表目标进行观测时,大气的强偏振效应会干扰甚至覆盖地物的偏振信息。因此,如何最大限度地消除大气的偏振效应对地物偏振效应的影响是偏振遥感的一个关键性问题。大气中性点是大气中偏振度趋近为零的区域。利用大气中性点进行地-气分离理论的核心思想是将探测器放置于中性点区域进行对地观测,以减弱大气偏振对地物偏振的影响。基于国内首次大气中性点偏振遥感航空飞行实验,通过处理和分析实验所得影像数据,分别得到了中性点位置和非中性点位置影像偏振度分布,发现中性点位置偏振度集中分布区域要明显小于非中性点位置,验证了利用大气中性点进行地-气分离理论的合理性和可行性,提出了利用中性点进行偏振遥感实验所需要的条件,并初步分析出,波长较长的波段更适合于偏振遥感观测。     

基于有限穿越可视图的时间序列网络模型

提出了一种改进的时间序列有限穿越可视图建网方法,并对三种可视图(可视图、水平可视图、有限穿越可视图)网络度分布进行了评价.结果表明:水平可视图网络均无法有效识别各类时间序列信号(周期、分形、混沌);对分形信号,可视图及有限穿越可视图网络均具有无标度幂律形式,但抗噪能力较差;对周期信号及混沌信号,有限穿越可视图网络比可视图具有更强的抗噪性.在此基础上,采用有限穿越可视图网络从油气水三相流电导波动信号中提取了度分布特征参数,通过其特征参数组合实现了对三种典型三相流流型(水包油泡状流、水包油泡状-段塞过渡流型及水包油段塞流)较好的辨识效果.     

Statistical properties of extragalactic radio sources

In this paper, a large sample of extragalactic radio sources is analysed to show their statistical properties. The core and total radio powers are used to determine the core-dominance parameter for galaxies, BL Lacertae objects and quasars; mutual correlations between core radio power, total radio power, redshift and core dominance parameter are examined for different subclasses. A statistically significant correlation between the total and core radio power is confirmed. There are no obvious correlations between core-dominance parameter and the total power for our whole sample and quasars, but there is a statistically significant anti-correlation for our galaxy sample. Some discussions and comparison of the correlations with those obtained by other authors are also given.     

Scaling behaviour in the truncated Zel'dovich approximation

Summary We analyse the scaling properties of the matter distribution generated by the truncated Zel'dovich approximation (TZA) for a universe dominated by a mixture of cold+hot non-baryonic dark matter. At the present epoch, the dark-matter distribution generated by TZA displays an intermediate scaling behaviour between about 4 and 60h ⁻¹ Mpc with a correlation dimensionD _q∼2 forq≥2. The possible implications of these results are considered.     

高分辨侧扫及合成孔径声纳图像与回波中类似水雷目标计算机检测与分类

计算机辅助目标识别与分类技术有可能可靠地在海底发现水雷及其它感兴趣的目标,高效省时,一致性强,不受操作员个体因素影响。自90年代以来,是多个研究部门的热点课题。近年来,合成孔径侧扫声纳技术日趋成熟,能提供更高分辨率的声图,更是促进了自动识别与分类的发展。 本文综合评述了高分辨侧扫及合成孔径声纳图像与回波中类似水雷目标- MLO (Mine Like Object)-计算机检测与分类-CAD/CAC（Computer Aided Detection/ Computer Aided Classification）-研究的发展,现状及趋向。     

I-factorial quantum torsors and Heisenberg algebras of quantized universal enveloping type

We introduce a notion of I-factorial quantum torsor, which consists of an integrable ergodic action of a locally compact quantum group on a type I-factor such that also the crossed product is a type I-factor. We show that any such I-factorial quantum torsor is at the same time a I-factorial quantum torsor for the dual locally compact quantum group, in such a way that the construction is involutive. As a motivating example, we show that quantized compact semisimple Lie groups, when amplified via a crossed product construction with the function algebra on the associated weight lattice, admit I-factorial quantum torsors, and give an explicit realization of the dual quantum torsor in terms of a deformed Heisenberg algebra for the Borel part of a quantized universal enveloping algebra.     

The inverse scattering problem for partially penetrable obstacles

We consider the direct and inverse problems for the scattering of a partially penetrable obstacle. Here ‘partially penetrable obstacle’ means that the waves transmit into the obstacle just from partial boundary of the obstacle with the rest of the boundary touching a known perfect and thin scatterer. The solvability of the direct scattering problem is presented using the classical boundary integral equation method. An interesting interior transmission problem is investigated for the purpose of solving the inverse obstacle scattering problem. Then the linear sampling method is proposed to reconstruct the shape and location of the obstacle from near field measurements. We note that the inversion algorithm can be implemented by avoiding the use of background Green function as a test function due to a mixed reciprocal principle.