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关键词： 信息物理系统   有限值逻辑系统   矩阵半张量积   当前状态不透明性   有限自动机  

摘要： 状态不透明性作为一种重要的机密属性,能够表征入侵者窃取系统隐私信息的能力。针对带有不可观测事件的信息物理融合系统(CPSs),该文提出一种基于矩阵半张量积(STP)的代数状态空间方法,并且分析与验证CPSs的状态不透明性。首先利用矩阵STP理论对CPSs的状态演化进行建模,得到系统的动态代数表达式,然后利用STP运算的特性,给出验证系统当前状态不透明性的充分必要代数条件。最后,通过数值仿真算例验证了方法的有效性。该文提出的基于矩阵STP方法为CPSs相关隐私分析与安全控制研究提供了一个新的思路和框架。

关键词： 三维裂缝/软孔隙网络模型   三维裂缝-孔隙网络模型   波动方程   频散衰减  

摘要： 波场在含流体的孔隙介质中传播时会产生频散和衰减现象.波场的频散和衰减与孔隙介质的岩石物理属性有关,包括孔隙度、渗透率、流体属性等.现有的三维裂缝/软孔隙网络模型利用椭圆截面纵横比的变化模拟从扁裂缝、软孔隙到硬孔隙的多种情况,而未考虑同时包含孔隙和裂缝的全局性网络空间.为了更好地描述裂缝-孔隙空间,本文提出同时包含裂缝和孔隙的三维裂缝孔隙网络模型,并给出渗透率的计算方法.通过体积平均法推导了三维裂缝/软孔隙网络模型和三维裂缝-孔隙网络模型的波动方程,利用平面波分析方法得到纵波频散/衰减曲线的表达式,同时应用数值模拟研究了总孔隙度、裂缝孔隙度、裂缝纵横比、裂缝数密度、孔隙流体黏度对纵波衰减和速度频散特征的影响.结果表明,在三维裂缝-孔隙网络模型下,总孔隙度、裂缝参数等对纵波频散衰减特征的影响与三维裂缝/软孔隙网络模型相似.具体表现为:纵波在高频段内出现频散和衰减现象.孔隙度的变化主要影响逆品质因子曲线峰值的大小;裂缝数密度主要控制速度显著变化的范围;裂缝纵横比对纵波速度和特征频率有显著影响.

关键词： 回音壁模式   封装微腔   受激布里渊散射  

摘要： 回音壁模式光学微腔是一种研究非线性光学现象的理想平台。在1 550 nm波段下成功实现了在CaF_(2)晶体微腔中产生五阶级联的受激布里渊散射激光。所用的CaF_(2)晶体微腔直径为12.6 mm,同时有着超高的品质因子,最高可以达到1.16×10^(8)。实验中发现,当大尺寸晶体腔与绝热的锥形光纤进行耦合时,能够激发出多个谐振模式,保证了能够方便地选择不同的谐振波长来匹配受激布里渊散射频移。可以消除在匹配微腔的自由频谱范围和布里渊频移时对微腔尺寸精准控制的需要。为了解决在微腔和波导耦合时的环境震动影响,还设计了一个可以精密耦合调节的封装平台,可以保证谐振腔和波导稳定的在氮气保护气体氛围中被耦合密封起来。产生的级联布里渊激光和设计出的稳定封装平台可以用于后续的应用开发,例如多波长布里渊激光器产生和基于布里渊激光的陀螺仪研发等。

关键词： 三维动脉自选标记   弥散张量成像   胶质瘤  

摘要： 目的分析三维动脉自选标记(3D-ASL)和弥散张量成像(DTI)定量参数在胶质瘤分级评估中价值。方法77例脑胶质瘤(BG)患者术前行3D-ASL、DTI扫描,根据术后病理结果分为高级组(46例)和低级组(31例),比较两组3D-ASL和DTI定量参数水平,并采用受试者工作曲线(ROC)分析其在BG分级中评估价值。结果高级组各项rCBFmax值高于低级组(P<0.01),而FA、ADC值低于低级组(P<0.01)。ROC曲线分析显示,rCBFmax、FA、ADC值及联合评估BG分级的AUC分别为0.930、0.798、0.771、0.991,其中联合及rCBFmax的AUC显著高于FA和ADC(P<0.05)。结论3D-ASL定量参数在BG分级评估中价值优于DTI,联合应用可提高评估价值。

关键词： 大学物理实验   光的双缝干涉   远程控制  

摘要： 为适应信息化技术发展的需要,突破传统物理实验对时空的限制,以光的双缝干涉实验为研究对象,依托物联网技术,创新性地设计和开发了的远程控制双缝干涉实验仪器。从光路模块、驱动模块和远程控制模块介绍了仪器的设计过程。远程控制实验仪器的开发为开放式远程实验教学平台建设提供了保障和新思路。

关键词： 矢量迭代优化算法   空间光调制器   飞秒激光   多焦点   光栅  

摘要： 本文提出了一种多焦点并行加工光栅的方法,主要利用矢量迭代优化算法,设计生成了多焦点的纯相位分布图。利用空间光调制器和纯相位分布图,可以将入射光调制成为所需的多焦点阵列。以1×11个点阵结构为例,利用飞秒激光加工系统结合空间光调制器实现了11路激光的并行加工,可以同时制备11条纳米级宽度的光栅结构,验证了矢量迭代优化算法可以产生高均匀度的多焦点,为提高飞秒激光加工效率提供了一种方法,在制备大规模光栅及微纳光学器件方面具有很高的应用价值。

关键词： semiconductor laser diode   high power   narrow line-width   high order Bragg gratings  

摘要： In order to obtain high power, narrow line width and near diffraction limit output semiconductor laser diodes, the high order Bragg gratings (HOBGs) and master oscillator power-amplifier (MOPA) have been fabricated in the waveguide of HOBGs-MOPA laser diodes with an emission wavelength of 980 nm. The longitudinal mode of HOBGs-MOPA was selected by the HOBGs with a period of 11. 37 mu m. The single-mode optical power is amplified by a tapered waveguide with an angle of 6 degrees. In this paper. we present a single mode laser diode with continuous wave power 2. 8 W at a 3 dB line-width of 31 pm. The laser diode operates in a close to diffraction-limited optical mode (M-2 =2. 51, laterally).

关键词： bisphosphonates   crystal structure   etidronate   physical properties   X-ray absorption near-edge structure spectroscopy  

摘要： Purpose Disodium etidronate is a bisphosphonate, compounds that are widely used in the treatment of bone disorders such as osteoporosis and Paget's disease. We investigated the physical properties of disodium etidronate tetrahydrate crystal, form I. Methods We used X-ray powder diffraction (XRPD), thermal analysis, dynamic vapor sorption (DVS), X-ray single crystal structure analysis, and phosphorus K-edge X-ray absorption near-edge structure (XANES) spectroscopy for the first time. Results XRPD and thermal analyses demonstrated that form I was dehydrated and transformed to an amorphous form, to a crystalline form II, and finally to a form III by heating. DVS measurements revealed that the amorphous form, form II, and form III were rehydrated to form I by humidification, and form I was stable even at 0% relative humidity. These results indicate that form I is the most stable solid-state under ambient conditions and is suitable as an API for manufacture in solid formulations. The phosphorus K-edge XANES spectra differed among form I, the amorphous form, and form II, which may be ascribed to the difference in the coordinate bond schemes between the phosphate moieties and sodium ions. The results demonstrated that the phosphorus K-edge XANES spectroscopy could be applied to the identification or the discrimination of crystal forms of the APIs containing phosphate moieties. Conclusions Acquired information about physical properties are crucial for manufacturing of solid formulations of disodium etidronate. XANES spectroscopy is a promising alternative method for evaluating the solid-state forms of APIs.

关键词： Graphene   Polymers interactions   Modeling   Quantum dots   Optoelectronics   Sensors  

摘要： Density functional theory as well as molecular mechanics force field (MMFF94) techniques are used to study intermolecular/intramolecular interactions, band offsets, physicochemical correlations, and nonlinear optical properties for 12 designed homo- and hetero-pyrrole-graphene quantum dots (PGQDs). Also, force field energy, minimum and maximum projection area, Van der Waals volume and 3D surface area, and total polar surface area for homo- and hetero-PGQDs are calculated. In addition, UV-Vis absorption spectra for homo- and hetero-PGQDs are computed. The interfacial electrons carry through functionalized GQDs with pyrroles bearings will help in screening the desired applications for proposed PGQDs as optoelectronic and memory switches devices.

关键词： chloride   concrete   corrosion resistance   polymer   rebar   steel  

摘要： Polymer coatings can be used to mitigate the corrosion of steel in high-chloride environments. Obtaining speciation information from thin corrosion layers can be important for understanding corrosion mechanisms, including polymer coating failure. This study outlines the effectiveness of collecting glancing angle x-ray absorption near edge spectroscopy (GA-XANES) spectra at the Fe K-edge to obtain chemical speciation information at the polymer/steel interface without removal of the polymer film. The depth of penetration of the incident x rays can be altered by changing the incidence angle, allowing for more fluorescence signal from corrosion products to be detected relative to the Fe metal fluorescence signal in GA-XANES spectra. This study demonstrates the use of GA-XANES to study thin layers of steel corrosion and obtain depth profile information of steel corrosion products beneath a polymethyl methacrylate polymer coating.