论绘画中的“视觉偏见”

当今,我们的视觉受到来自外在世界的各种影响,受到干扰后的视觉就变得不再纯粹,这使得作为视觉艺术的绘画失去了本应有的生命力。本文从视觉偏见出发来论述它产生的原因及打破视觉偏见的途径。     

Spark discharge generator as a stable and reliable nanoparticle synthesis device: Analysis of the impact of process and circuit variables on the characteristics of synthesized nanoparticles

Nanotechnology offers the promise of harnessing quantum properties not available in the bulk phase. These desirable properties are highly dependent on size and composition. Generators that control these variables are therefore essential for progress in the field. The spark discharge generator (SDG) is an outstanding aerosol route for nanoparticle synthesis, which stands out due to its fast kinetics, scalability, high purity, accuracy and reproducibility, with the added advantage of allowing the synthesis of nanoparticles of any conducting material. These advantages are a consequence of its vast heating and cooling rates, its intrinsic and easily controllable electronic variables at the reach of a click. However, the mechanistic impact of these variables on the actual aerosol generated is still not fully understood. In this work, we constructed an SDG and systematically studied its behavior with particular interest in the effect that resistance, capacitance, inductance, flow rate, gap separation and current have on the electrical behavior of the spark. Our model system produced primarily Fe and Cu nanoparticles with measured concentrations ranging 5*10⁵ – 2*10⁷ part/cm³, and mean agglomerate sizes of 5 – 80 nm. We discuss how the spark influences particle size and number concentration and provide useful correlations that link dependent with independent variables. Remarkably, a finite resistance produces a maximum in the output of the generated aerosols. This suggests a direct link between RLC properties of the circuit and cabling into the frequency of the spark, and nanoparticle number concentration, indicating potential for exploiting such behavior towards maximizing nanoparticle generation. Furthermore, we discuss a link between spark oscillations and energy release with its consequent aerosol generation.     

基于液体静力称量法的纯水密度测量

分析了液体静力称量法测量密度的原理和体积测量中纯水密度的特性公式,推导了由己知密度的固体标准来测量液体密度的计算公式。利用固体密度基准量传装置,通过静力称量法为固体密度标准硅球赋值,其相对测量不确定度3×10^-6(k=2)。在20℃时利用高精度液体密度测量装置,通过静力称量法将固体标准(硅球)密度传递至纯水密度,与Tanaka模型比对,E_n值为0.059,比对结果等效。实验结果不仅验证了高精度液体密度测量装置,还验证了20℃纯水密度模型的理论值。     

纯滞后环对数字电源环路影响的研究

研究了滞后环对数字电源的影响和滞后环的等效简化模型,给出了基于Matlab数字电源补偿器的设计步骤。仿真和实验表明,通过该方法设计的数字电源环路稳定性得到了有效保证。     

A low‐complexity design for distributed containment control of networked pure‐feedback systems and its application to fault‐tolerant control

This paper addresses a low‐complexity distributed containment control problem and its extension to fault‐tolerant control for networked nonlinear pure‐feedback systems under a directed graph. The multiple dynamic leaders are neighbors of only a subset of the followers described by completely non‐affine multi‐input multi‐output pure‐feedback dynamics. It is assumed that all followers' nonlinearities are heterogeneous and unknown. The proposed containment controller is implemented by using only error surfaces integrated by performance bounding functions and does not require any differential equations for compensating uncertainties and faults. Thus, compared with the previous containment control approaches for multi‐agent systems with unknown non‐affine nonlinearities, the distributed containment control structure is simplified. In addition, it is shown that the proposed control scheme can be applied to the fault‐tolerant containment control problem in the presence of unexpected system and actuator faults, without reconstructing any control structure. It is shown from Lyapunov stability theorem that all followers nearly converge to the dynamic convex hull spanned by the dynamic leaders and the containment control errors are preserved within certain given predefined bounds. Copyright © 2016 John Wiley & Sons, Ltd.     

纯电动轿车制动能量回收节能潜力仿真分析

从整车能量消耗入手,分析纯电动轿车能量流机理,建立整车耗电量与工况、整车参数、部件效率以及制动能量回收比例之间的函数关系,通过求解基于工况的特征权值,研究不同车型在各工况中的节能潜力,为纯电动轿车整车参数匹配提供理论依据。通过分析制动力分配策略,量化制动能量回收比例,进一步计算整车节能度,研究制动能量回收效果。通过在Matlab/Simulink中构建仿真模型,完成整车节能度的计算,并与AVL/Cruise仿真结果进行对比分析,结果表明本文方法能够很好地反映整车节能效果,完全满足整车节能潜力分析的要求。     

汉字读音判断时非文盲右脑活动特征的fMRI研究

利用功能性磁共振成像（fMRI）技术探讨汉字语音判断时非文盲的大脑活动特征。实验使用汉字语音和纯音比较了中国人文盲和非文盲语音加工过程脑机制的差异。结果表明文盲与非文盲汉字语音加工脑机制不同,且非文盲的脑活动强,尤其是右脑。     

纯电动汽车用永磁同步电机空间矢量控制系统建模与仿真

在分析小型纯电动汽车动力学方程和永磁同步电机PMSM数学模型的基础上,建立PMSM驱动汽车的数学模型,并利用空间矢量脉宽调制技术和模糊PID控制算法设计了车速-电流双闭环控制系统,以驱动汽车变速运行。在Matlab 7.6/Simulink环境下搭建了纯电动汽车车速-电流双闭环控制系统动态仿真模型,依据行驶需求对电动汽车在某档位的车速与转矩进行了仿真分析,并对控制策略进行了静、动态性能验证。仿真结果表明:该系统具有响应速度快、精度高、抗干扰能力强等优点,为实际纯电动汽车驱动控制系统的分析与设计提供了新的思路。     

间二硝基苯精制工艺的改进

对传统的精制间二硝基苯的方法进行了改进，即利用相转移催化磺化反应，对粗制间二硝基苯进行处理，将其中的邻、对位异构体转化为对应的硝基苯磺酸盐，从而达到提纯间二硝基苯的目的。     

低温烧成纯铝酸钙水泥的机理研究

在常压条件下水热合成水化铝酸钙，然后经过低温烧成制备了纯铝酸钙水泥。通过力学性能的测试，并采用XRD，DTA等分析方法，探讨了低温烧成纯铝酸钙水泥的机理。研究结果表明：采用水热合成处理方法制备纯铝酸钙水泥，烧成温度低（1250℃，制得熟料活性好，强度高，是替代传统烧结法制备纯铝酸钙水泥的新方法。