TMS320F2812系统中的软件复位方法

控制系统中大多采用电压监控或者看门狗电路,以保证系统的稳定运行。采用硬件复位的方式,可以通过按键开关在任意时刻进行系统复位,系统复位后程序重新开始运行。但有些系统中有人机界面显示,主机在机箱内部,人工复位很不方便,所以采用界面方式的软件复位。     

一个新的基于权限的委托模型CPPBDM

基于权限的委托模型PBDM实现了权限的委托,其实现方法是将角色进行划分,使组织的角色继承关系变得复杂,模型的实现和管理变得烦琐.为此,提出对PBDM进行改进的基于权限划分的新模型CPPBDM,模型引入新的角色间关系:委托继承、激活指派;新模型能够实现基于权限的委托与角色代理,简化了模型的实现与管理.     

HClO对贻贝粘附单元DOPA氧化的理论研究

采用量子化学密度泛函理论(DFT)研究贻贝粘附单元DOPA(3,4-二羟基苯丙氨酸)的结构与性质,得分子的几何构型、原子电荷分布、反应活性及热力学等参数,表明:DOPA苯环易与HClO(次氯酸)发生亲电取代反应(1),生成3-氯4,5-二羟基苯丙氨酸,阻碍生成贻贝内超强粘附单元DOPA二联体,降低粘附蛋白间粘性;DOPA侧链易与HClO发生亲电亲核反应(2),促使DOPA侧链的断裂,降低粘附蛋白内粘性;在相同温度下,反应(1)和反应(2)的△G<0,且△G(1)<△G(2),反应(1)较易发生.     

Vibration analysis of cable-driven parallel manipulators

A cable-driven parallel manipulator is a manipulator whose end-effector is driven by a number of parallel cables instead of rigid links. Since cables always have more flexibility than rigid links, a cable manipulator bears a concern of possible vibration. Thus, investigation of vibration of cable manipulators caused by cable flexibility is important for applications requiring high system stiffness or bandwidth. This paper provides a vibration analysis of general 6-DOF cable-driven parallel manipulators. Based on the analysis of the natural frequencies of the multibody system, the study demonstrates that a cable manipulator can be designed stiff enough for special applications like the cable-manipulator based hardware-in-the-loop simulation of contact dynamics. Moreover, under an excitation, a cable may vibrate not only in its axial direction, but also in its transversal direction. The paper also analyzes the vibration of cable manipulators caused by cable flexibilities in both axial and transversal directions. It is shown that the vibration of a cable manipulator due to the transversal vibration of cables can be ignored comparing to that due to the axial flexibility of cables.     

浅谈《周易》中蕴含的设计思维

随着时代的发展,设计日益以一种文化的形式影响和改变着社会生活方式,文化的内涵是设计中不可忽视的要素,尤其在全球文化一体化危机中,人们更青睐于设计作品表达的精神内涵,通过造型形象所传达的内在文化性、思想性,以及浓厚的深远意境和文化品味。于是,越来越多的设计师把关注的目光投向了中国传统文化的发掘上。《周易》是我国古代重要的认识世界的首部经书,考察我国古代的艺术思维观念必然对今天的设计文化内涵的形成具有借鉴意义。     

基础位移激励下椭圆抛物面碳纤维索网的振动

在考虑温度变化的基础上,研究椭圆平面双曲抛物面碳纤维索网在基础激励下的非线性振动问题,建立了椭圆平面双曲抛物面碳纤维索网在基础位移激励下的非线性振动方程,采用Galerkin原理及KBM法求得了椭圆平面双曲抛物面碳纤维索网非线性振动的近似解．在把碳纤维索网与钢丝索网比较的基础上,讨论分析了位移激励、温度、振幅、外阻尼等因素对椭圆平面双曲抛物面碳纤维索网非线性振动的影响,得到了碳纤维索网对温度变化不敏感,而钢丝索网受温度的影响却很大,且碳纤维索网振动特性优于钢丝索网振动特性的结论．     

UPS电源的选择与使用

随着计算机和网络的快速发展和广泛应用,UPS市场已进入了一个成熟阶段。如何选择与使用UPS已经成为用户最关心的问题。本文主要介绍了UPS的种类和作用,指出了用户选用、维护UPS应注意的一些问题。     

Two-dimensional wavelet transform and application to holographic particle velocimetry

The goal of holographic particle velocimetry is to infer fluid velocity patterns from images reconstructed from doubly exposed holograms of fluid volumes seeded with small particles. The advantages offered by in-line holography in this context usually make it the method of choice, but seeding densities sufficient to achieve high spatial resolution in the sampling of the velocity fields cause serious degradation, through speckle, of the signal-to-noise ratio in the reconstructed images. The in-line method also leads to a great depth of field in paraxial viewing of reconstructed images, making it essentially impossible to estimate particle depth with useful accuracy. We present here an analysis showing that these limitations can be circumvented by variably scaled correlation, or wavelet transformation. The shift variables of the wavelet transform are provided automatically by the optical correlation methodology. The variable scaling of the wavelet transform derives, in this case, directly from the need to accommodate varying particle depths. To provide such scaling, we use a special optical system incorporating prescribed variability in spacings and focal length of lenses to scan through the range of particle depths.

Calculation shows, among other benefits, improvement by approximately two orders of magnitude in depth resolution. A much higher signal-to-noise ratio together with faster data extraction and processing should be attainable.

     

An Efficient One-Arrow-Two-Hawks Strategy Achieves High Efficiency and Stable Batch Variance for Benzodifuran-based Polymer Solar Cells

With the development of organic solar cells (OSCs), the high-performance and stable batch variance are becoming a new challenge for designing polymer donors. To obtain high photovoltaic performance, adopting polymers with high molecular weight as donors is an ordinary strategy. However, the high molecular weight need to subtly control the reaction time and state, inevitably caused batch-to-batch variations. Herein, a strategy of steric effect is applied to benzodifuran (BDF)-based polymer by introducing different positions of Cl atom, producing two polymers PBDFCl-1 and PBDFCl-2. The more twisted side chains conformation not only achieve the control of moderate molecular weight for PBDFCl-2, but also easily form molecular stacking through adopting BDF unit and maintain sufficient polymeric crystallinity. Due to the optimized stacking mode and good blend miscibility, PBDFCl-2-based device exhibitsa more elegant power conversion efficiency (PCE) of 17.00% compared to PBDFCl-1-based device. This is the highest efficiency record for BDF-based binary OSCs. Meanwhile, the PCE device variation of the different molecular weights for PBDFCl-2 is little, indicating the reduction of the batch variation. Therefore, smartly using steric effect of Cl atom in strong crystalline BDF unit can form efficient molecular stacking regulations and realize the coordination of high-performance and stable batch variance.     

身份保持约束下的面部图像超分辨率重建方法

低分辨率是影响人脸识别精度的重要因素。一种有效方法是使用图像超分辨率技术对低分辨率图像重建,生成超分辨率图像后再对其作人脸识别,从而克服低分辨率面部图像对人脸识别的限制。但是,现有超分辨率方法在重建过程中往往忽略了保持其原始身份信息,这直接影响生成图像的人脸识别结果。针对上述问题,提出了一种身份保持约束下的面部超分辨率重建方法IPNet,在提高低分辨率面部图像质量的同时,能保持重建后的面部图像身份。IPNet方法将语义分割网络和面部生成器相结合,通过语义分割网络提取低维隐码和多分辨率空间特征,进而指导面部生成器输出接近于原图的真实面部图像。在此基础上引入人脸识别网络,将身份信息整合到超分辨率方法中,从而约束重建前后的面部图像身份保持一致。实验结果表明,IPNet方法在超分辨率图像质量和身份保持上均优于其他对比方法。