基于荧光熄灭的硫阴离子选择性光化学敏感膜

基于Ｓ＾２－对固定于增塑的聚氯乙烯膜上的荧光素汞的荧光熄灭，研制了Ｓ＾２－选择性光化学敏感膜。该膜测定Ｓ＾２－的浓度范围为１０＾－９ｍｏｌ／Ｌ～１０＾－６ｍｏｌ／Ｌ，其荧光信号具有选择性强、重现性高且可逆的特点，适用于水相中硫化物的测定。     

Signal Level Simulation Modeling for Antenna Array of Aperture Synthesis Radiometer Based on the Equivalent Complex Baseband Representations

This paper presents a signal-level simulation model for simulating the process that antenna array of Aperture Synthesis Radiometer (ASR) collecting thermal radiation and transforming thermal radiation signal into radio frequency (RF) signal. By using the equivalent complex baseband signals to represent the practical thermal radiation and RF signals, simulation efficiency is improved significantly. The statistic characteristics of simulation results are found to match the corresponding theoretical analysis well. Results of an imaging simulation experiment show that this model can be employed in ASR system-level simulator design.     

遥感技术在孝丰-三门湾活动断裂调查中的应用——以杭州地区为例

遥感技术可以在宏观上对活动断裂及其构造特征进行全面的解译和识别．在区域遥感影像图制作和地质解译的基础上，采用增强和融合等图像处理方法，提高了遥感影像清晰度和解译精度，同时结合野外调查、测量以及断裂活动年代样品的采集和测定，对孝丰-三门湾断裂进行了详细的研究，查明了它的空间展布，并鉴定了活动时代和运动性质．研究结果表明，孝丰-三门湾断裂在杭州地区以挤压逆冲运动为主，兼有左旋走滑运动，并在各个地段和各个时期表现形式截然不同，影响了杭州南部地区地层沉积和构造演化．该断裂对杭州地区历史地震和现代地震具备一定的控制作用，可能在晚更新世以来有过活动．     

Optical technique for classification, recognition and identification of obscured objects

The capability to classify, recognize and to identify objects from spatially low resolution images has high significance in security related applications especially in a case that recognition of camouflaged object is required.In this paper we present a novel approach in which the scenery containing obscured objects which we wish to classify, recognize or identify is illuminated by spatially coherent beam (e.g. laser) and therefore secondary speckles pattern is reflected from the objects. By special image processing algorithm developed for this research and which is basically based upon temporal tracking of the random speckle pattern one may extract the temporal signature of the object. And right after, to use it for its classification (e.g. its separation from the other objects in the scenery), its recognition and identification even in a case that the imager provides poor spatial resolution that by itself does not allow doing the specified detection related operations.     

Fast Response Oxygen Micro-Optodes Based on Novel Soluble Ormosil Glasses

 A new type of phenyl substituted ormosils as a matrix for oxygen-sensitive micro-optodes is described. The new ormosils combine features of classical polymers such as solubility in organic solvents and those of sol–gel glasses such as mechanical stability and a porous structure. They make possible a simple and fast fabrication of microsensors with reproducible properties. The influence of the conditions during the polymerisation process (precursor composition and thermal treatment) on the sensing properties has been studied in detail. Oxygen-sensitive films with ruthenium(II)–tris-(4,7-diphenyl-1,10-phenanthroline) and platinum(II)–octaethylporphyrin as indicators were characterised with respect to their mechanical and photophysical properties. Photostability, oxygen sensitivity, response behaviour and signal intensities of the sensing films and the micro-optodes were examined. Micro-optodes based on the new sensing materials are fast responding, photostable and can be produced with a sufficient batch to batch reproducibility. Compared to previously described oxygen micro-optodes, where polystyrene was used as immobilisation matrix, the new sensors can be autoclaved and show favourable properties such as a faster response and a higher sensitivity. They possess many potential applications in medical and biological research. Received June 12, 1998. Revision December 10, 1998.     

Point-diffraction interferometer for atmospheric adaptive optics in strong scintillation

This paper evaluates the performance of a point-diffraction interferometer for closed-loop adaptive optics. A point-diffraction interferometer was built using a modified Mach-Zehnder set-up. The system was used in closed-loop using a SLM to implement a square, 12 × 12, piston-only segmented corrector with a stroke of ±π. Its performance was tested for the case of atmospheric turbulence aberrations. The investigation showed, through simulation and experiment, that the point-diffraction interferometer worked in closed-loop operation in both uniform intensity and scintillated aberrations. Its robustness in the presence of phase discontinuities makes it a promising option for wavefront sensing in strong scintillation.     

Image Encryption Scheme with Compressed Sensing Based on a New Six-Dimensional Non-Degenerate Discrete Hyperchaotic System and Plaintext-Related Scrambling

Digital images can be large in size and contain sensitive information that needs protection. Compression using compressed sensing performs well, but the measurement matrix directly affects the signal compression and reconstruction performance. The good cryptographic characteristics of chaotic systems mean that using one to construct the measurement matrix has obvious advantages. However, existing low-dimensional chaotic systems have low complexity and generate sequences with poor randomness. Hence, a new six-dimensional non-degenerate discrete hyperchaotic system with six positive Lyapunov exponents is proposed in this paper. Using this chaotic system to design the measurement matrix can improve the performance of image compression and reconstruction. Because image encryption using compressed sensing cannot resist known- and chosen-plaintext attacks, the chaotic system proposed in this paper is introduced into the compressed sensing encryption framework. A scrambling algorithm and two-way diffusion algorithm for the plaintext are used to encrypt the measured value matrix. The security of the encryption system is further improved by generating the SHA-256 value of the original image to calculate the initial conditions of the chaotic map. A simulation and performance analysis shows that the proposed image compression-encryption scheme has high compression and reconstruction performance and the ability to resist known- and chosen-plaintext attacks.     

Voltammetric Anion Sensors based on Redox‐active Ferrocene‐bearing Macrocyclic Amides

Reactions between 5‐ferrocenylisophthalic dichloride and 1,2‐bis(o‐aminophenoxy)ethane yield 1:1‐ and 2:2‐cyclization products with amide linkages, which are marked as L1 and L2 , respectively. The crystal structure of the 2:2‐macrocycle L2 is determined by X‐ray single crystal structure analysis. Interestingly, L2 affords a folded conformation due to the intermolecular π–π interaction between two isophthaloyl groups, so as to stabilize the marcocylic conformation. The electrochemical anion sensing studies of L1 and L2 show that they have a good ability to recognize H₂PO₄^–, and the 2:2‐cyclization products ( L2 ) with two ferrocene groups, more anion binding sites, and larger cavities, give better electrochemical anion recognition results than L1 .     

Coumarin-based urea-amide scaffold in ratiometric fluorescence sensing of CN−

Coumarin-based urea and urea–amide scaffolds 1–3 have been designed and synthesized for the selective and naked eye detection of cyanide ion. Of the three, compound 3 exhibits ratiometric fluorescence change selectively in the presence of CN^? and validates the rationality in designing anion receptor. Upon interaction with CN^?, the color of the solution of 3 in CH₃CN under UV exposure becomes bright yellow, which is beneficial for its naked eye detection. Addition of CN^? of ～10^?4 M brings nice color change from colourless to yellow in ordinary light. The sensing event is supposed to be due to nucleophilic addition of CN^? to the coumarin unit enabling intramolecular charge transfer (ICT) mechanism.