卡塞格伦镜头的猫眼效应激光反射特性

卡塞格伦(Cassegrain)及类卡塞格伦式光学镜头在光电装备中应用广泛.为了研究具备卡塞格伦式光学镜头的光电装备所特有的猫眼效应特性,采用ZEMAX光学设计分析软件建立了卡塞格伦镜头反射模型,利用物理光学传输方法仿真分析了其猫眼效应反射特性,并得出了猫眼效应可探测入射角范围.对一特定卡塞格伦镜头进行了激光辐照实验,得到了猫眼效应反射光斑图像,测试了猫眼效应绝对反射率以及反射光发散角.结果表明,当发射系统位于该卡塞格伦镜头的视场内时,可以探测到猫眼效应反射光,中心遮挡造成原路返回处光强分布中心能量降低,猫眼效应绝对反射率为11.48%,反射光发散角为3.3 mrad,按照假设条件可以满足30 km内激光主动探测的需要.     

A Novel Color Image Segmentation Approach Based on Neutrosophic Set and Modified Fuzzy c-Means

Color image segmentation is an important technique in image processing, pattern recognition and computer vision. Many segmentation algorithms have been proposed. However, it is still a complex task especially when there are noises in the images, which have not been studied in much detail. Neutrosophic set (NS) studies the origin, nature, and scope of neutralities. In this paper, we apply NS in the color image and define some new concepts. A directional α-mean operation is proposed to reduce the set indeterminacy. The fuzzy c-means clustering method is improved by integrating with NS and employed for the color image segmentation. The computation of membership and the clustering termination criterion are redefined accordingly. Moreover, a validity criterion is employed to determine the optimal clustering number. Numerical experiments serve to illustrate the effectiveness and reliability of the proposed approach. Experimental results demonstrate that our approach can segment color images automatically and effectively, produce good results as favorably compared to some existing algorithms. The optimal clustering number is determined automatically and no prior knowledge is required. Especially, it can segment both images with the simple and distinct objects and the images with complex and noisy objects, which is the most difficult task for color image segmentation.     

一种电信级手机令牌动态口令系统的架构设计及其实现

对动态口令技术和手机令牌业务进行了概述,重点对电信级手机令牌动态口令系统架构、关键技术实现以及主要业务流程进行了分析和探讨,最后对其应用前景进行了展望.     

集成电路光刻镜扫描控制系统

用同步辐射光源进行大规模集成电路和微器件光刻是现阶段的一项高新技术。本文介绍同步辐射光刻的镜扫描控制系统。它的设计思想,所采用的方法以及最优控制等都具有科技应用和经济价值。     

中国低空大气波导出现概率和波导特征量的统计分析

本文简要说明了我们对大气波导的统计方法，并对统计结果作了讨论和分析。文中详细讨论了中国低空大气波导在不同地区的出现情况，说明了它们在各地出现概率随季节月份的变化情况及日变化情况，还说明了悬空波导和贴地波导基本分布状况；对于波导顶高、强度、厚度、高度等特征量，主要给出了它们的平均值和波导在不同数值上的分布。结果表明，我国低空大气波导出现的高概率区是南部沿海、东南沿海、东部沿海和西北地区中部；我国的四大高原、天山以北和东北平原是无波导区；我国低空大气波导的顶高一般在地面上２０００ｍ以内，强度在０～２０Ｍ单位之间，厚度一般是１００～５００ｍ，高度是西北地区绝大部分为０米，沿海地区大多数超过３００ｍ。同时文中也讨论了我国低空大气波导的分布和我国各地的具体地理位置、气候条件的相关情况。     

激光扫描转镜扫描轨迹的分析计算

扫描转镜是激光扫描探测系统的重要组成部分。从几何光学原理出发,以旋转六面转镜扫描为例,推导出扫描轨迹的表达式,分析了入射光线位置与扫描轨迹的关系,并给出了扫描角度与扫描轨迹的关系曲线。系统本身的结构特点是产生扫描非线性和非对称性的根源。为了减小扫描轨迹的非线性,提出了一种使用曲面反射镜的扫描系统,并对其扫描轨迹进行了求解和计算。由计算结果可知,该系统能有效克服平面转镜扫描系统的非线性特性。     

Rolling Friction Enhanced Free‐Standing Triboelectric Nanogenerators and their Applications in Self‐Powered Electrochemical Recovery Systems

Heavy metals contained in wastewater are one of the most serious pollutions in natural resources. A self‐powered electrochemical recovery system for collecting Cu ions in wastewater by incorporating a rolling friction enhanced freestanding triboelectric nanogenerator (RF‐TENG) is developed here. The RF‐TENG utilizes integrated cylindrical surfaces using the conjunction of rolling electrification and freestanding electrostatic induction, which shows outstanding output performance and ultrarobust stability. By using the kinetic energy of flowing water, a collection efficiency of up to 80% for Cu²⁺ ions in wastewater has been achieved. Self‐powered electrochemical systems are one of the most promising applications of TENGs for independent and sustainable driving of electrochemical reactions without the need for any additional power supply. This research is a substantial advancement towards the practical applications of triboelectric nanogenerators and self‐powered electrochemical systems.     

Practical asymmetric amine nucleophilic approach for the modular construction of protected α-quaternary amino acids

We report the first amine nucleophilic approach for the modular construction of enantioenriched protected α-quaternary amino acids. The key to success is the use of an alcohol solvent, which makes a rationally designed COOMe-bonded Cu-allenylidene electrophilic intermediate stable enough to couple with amine nucleophiles before its decomposition. The reaction features wide functional group tolerance with high enantioselectivity, typically >90% ee, and is amenable to the modification of commercially available bioactive molecules. The resultant protected α-amino acids could be readily converted into a number of precious enantioenriched amines featuring α-hindered tertiary carbon centers, which are otherwise synthetically quite challenging, including those of α-amino aldehyde, peptides or α-vinyl amino ester with >92% ee in excellent yields. This protocol could be utilized for the synthesis of the protected bioactive α-ethylnorvaline in 3 steps, a significant advancement in comparison to an 11-step sequence reported previously.

We report the first amine nucleophilic approach for the modular construction of enantioenriched protected α-quaternary amino acids.     

Oxygen-supplied mesoporous carbon nanoparticles for enhanced photothermal/photodynamic synergetic therapy against antibiotic-resistant bacterial infections

Pandemic and epidemic spread of antibiotic-resistant bacterial infections would result in a huge number of fatalities globally. To combat antibiotic-resistant pathogens, new antimicrobial strategies should be explored and developed to confront bacteria without acquiring or increasing drug-resistance. Here, oxygen saturated perfluorohexane (PFH)-loaded mesoporous carbon nanoparticles (CIL@ICG/PFH@O₂) with photothermal therapy (PTT) and enhanced photodynamic therapy (PDT) utility are developed for antibacterial applications. Ionic liquid groups are grafted onto the surface of mesoporous carbon nanoparticles, followed by anion-exchange with the anionic photosensitizer indocyanine green (ICG) and loading oxygen saturated PFH to prepare CIL@ICG/PFH@O₂. These CIL@ICG/PFH@O₂ nanoparticles exhibit effective PTT and enhanced PDT properties simultaneously upon 808 nm light irradiation. In vitro assays demonstrate that CIL@ICG/PFH@O₂ shows a synergistic antibacterial action against antibiotic-resistant pathogens (methicillin-resistant Staphylococcus aureus and kanamycin-resistant Escherichia coli). Moreover, CIL@ICG/PFH@O₂ could effectively kill drug-resistant bacteria in vivo to relieve inflammation and eliminate methicillin-resistant Staphylococcus aureus-wound infection under NIR irradiation, and the released oxygen can increase collagen deposition, epithelial tissue formation and blood vessel formation to promote wound healing while enhancing the PDT effect. This study proposes a platform with enhanced PTT/PDT effects for effective, controlled, and precise treatment of topical drug-resistant bacterial infections.

We report oxygen saturated perfluorohexane (PFH)-loaded mesoporous carbon nanoparticles (CIL@ICG/PFH@O₂) with photothermal therapy (PTT) and enhanced photodynamic therapy (PDT) utility for antibacterial applications.     

Structural Investigation of the Interaction Mechanism between Chlorogenic Acid and AMPA Receptor via In Silico Approaches

Chlorogenic acid (CGA), an important metabolite in natural plant medicines such as honeysuckle and eucommia, has been shown to have potent antinociceptive effects. Nevertheless, the mechanism by which CGA relieves chronic pain remains unclear. α-amino-3-hydroxy-5-methyl-4-isooxazolpropionic acid receptor (AMPAR) is a major ionotropic glutamate receptor that mediates rapid excitatory synaptic transmission and its glutamate ionotropic receptor AMPA type subunit 1 (GluA1) plays a key role in nociceptive transmission. In this study, we used Western blot, surface plasmon resonance (SPR) assay, and the molecular simulation technologies to investigate the mechanism of interaction between CGA and AMPAR to relieve chronic pain. Our results indicate that the protein expression level of GluA1 showed a dependent decrease as the concentration of CGA increased (0, 50, 100, and 200 μM). The SPR assay demonstrates that CGA can directly bind to GluA1 (K_D = 496 μM). Furthermore, CGA forms a stable binding interaction with GluA1, which is validated by molecular dynamics (MD) simulation. The binding free energy between CGA and GluA1 is −39.803 ± 14.772 kJ/mol, where van der Waals interaction and electrostatic interaction are the major contributors to the GluA1–CGA binding, and the key residues are identified (Val-32, Glu-33, Ala-36, Glu-37, Leu-48), which play a crucial role in the binding interaction. This study first reveals the structural basis of the stable interaction between CGA and GluA1 to form a binding complex for the relief of chronic pain. The research provides the structural basis to understand the treatment of chronic pain and is valuable to the design of novel drug molecules in the future.