Effect of Molding Temperature on Shape Memory Performance of SMPC

Abstract

Carbon fiber reinforced shape memory polymer composite (SMPC) is a kind of smart material with shape memory characteristics, which is widely used in aerospace, biomedicine, robotics and other fields. In this paper, SMPC was prepared by heating molding process at five different molding temperatures. The effect of molding temperature on the shape memory performance of SMPC was studied. The results show that the shape memory properties of SMPC are closely related to the infiltration effect during the preparation process. When the molding temperature is 70?°C, SMPC has an optimum penetration effect and the preparation defects are effectively controlled. The shape fixing rate is 84.3%, and the shape recovery rate is 94.7%, which lays a foundation for the better application of shape memory composite.     

三种提高褐煤锅炉中速磨煤机干燥出力方法的对比分析

介绍了三种提高褐煤锅炉中速磨煤机制粉系统干燥出力的方法,分析了其系统特征、运行情况及存在的问题,并对优缺点进行对比。结果表明:热一次风蒸汽加热系统布置简单、工程实施难度小、锅炉效率高、成本低、干燥出力提升效果明显。     

污泥样品中稀土元素的检测方法研究

取稀土工业园区的污水处理设施和受影响河流的的污泥样品,分别采用三种样品预处理方法(敞开式酸溶法、石墨加热消解和微波消解法)进行对比研究,结果表明:石墨消解法前处理污泥样品后,使用ICP-MS测定其中稀土元素(Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu),其方法简便快捷,检出限低,准确度好。     

NEXAFS study of electronic and atomic structure of active layer in Al/indium tin oxide/TiO2 stack during resistive switching

We have studied the stability of the resistive switching process in the Al/(In₂O₃)_0.9(SnO₂)_0.1/TiO₂ assembly grown by atomic layer deposition. Besides electrical characterization the effect of electric field on the atomic electronic structure of the TiO₂ layer was studied using near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The region of the current instability in the I-V characteristics was revealed. Presumably this current instability is supported by the amorphous structure of the TiO₂ film but is initiated by the surface morphology of the Al substrate. A formation of the O₂ molecules was established which occurs specifically in the region of the current instability that is a result of electrical Joule heating manifestation.     

High-Current-Density field emission from self-heating printed carbon nanotubes

High-current-density field emitters are considered as the potential and necessary components for compact high definition x-ray sources and high-power cold cathode microwave amplifiers. In this report, high-current-density field emission from self-heating printed carbon nanotubes is introduced. Large emission current causes large heat that increases the temperature of the emitters. The temperature is estimated to be more than ~1600 K. Localized surface field and high temperature both drive more electrons escaping from the emitters, and the maximum current density is larger than ~2.7 A/cm² that will satisfy the need of most vacuum electron devices including x-ray sources and microwave electron devices.     

ON STOCHASTIC CONVERGENCE THEOREMS FOR THE FUZZY C-MEANS CLUSTERING PROCEDURE∗

The fuzzy c-means clustering algorithm has been well studied for equal weight distributions on a finite set. Suppose that this situation is generalized to an arbitrary probability distribution on a finite dimensional Euclidean space, assuming that the second moment of the distribution is finite. Now choose ever larger finite random samples from this distribution and compute the standard optimal membership functions for a fuzzy partition into c clusters. Then the convergence of the cluster center points is established in the Hausdorff sense with probability one, provided that there is a unique optimal center point set. These optimal center points are the fixed point of a simple operator, and there is a corresponding iterative algorithm that generalizes the usual procedure.     

Multi-stage sequential uniform price auction mechanism for divisible goods

In this paper, we study the problem of auctioning a kind of continuous homogeneous divisible goods, and present a multi-stage sequential auction mechanism of divisible goods under uniform price. In this mechanism, the auction process is divided into multiple stages, all bidders satisfy the sequential rationality conditions, all bidders are asymmetric, every bidder is allowed to submit a nonincreasing continuous demand function in each round bidding, every bidder’s valuation to per unit of the goods is independent private information, and if a bidder does not obtain the quantity he wants in former stage auction, he still have another opportunity to obtain some quantity in the later stage auction. For this mechanism, we explore the formation process and composition of equilibrium points in each stage auction, and discuss the optimal strategy selection for bidders, then give the detail steps and an application example to show how to implement this multi-stage sequential auction mechanism. The conclusions can be drawn that our auction mechanism is an efficient incentive mechanism, and can effectively reduce many underpricing equilibrium and can yield higher expected income than a single uniform price auction for the auctioneer. It also can avoid the occurrence of failure auction (equilibrium does not exist), and effectively extend and improve the traditional single stage uniform price auction mechanism.     

均匀内水压力作用下圆形混凝土衬砌隧洞配筋设计探讨

基于对规范隧洞衬砌结构设计方法的分析探讨,考虑实际隧洞衬砌配筋应力状况,提出便于设计者进行均匀内水压力下圆形混凝土衬砌隧洞结构计算分析方法。按照此方法进行隧洞衬砌设计,计算过程简单清晰,设计分析结论明确,可以满足工程设计要求。     

立式连退炉加热段温度控制方法及应用

加热段温度控制是立式连续退火炉的核心和关键子系统,针对加热段温度控制大滞后、非线性、多扰动的特点,设计一种串级温度控制系统,它以炉区负荷控制为外环,助燃空气-燃气交叉控制为内环,配合带钢温度纠偏控制、过温控制、调节器参数自适应等辅助手段,提高连退炉温度控制的精度、响应速度以及燃气加热的效率。所述连退炉加热段温度控制方法已在某冷轧厂1850 mm连续退火炉工程上成功应用,并取得良好的控制效果。     

控制方向未知的时变不确定系统的重复控制

本文考虑一类具有未知时变参数并且控制方向未知的非线性系统的重复学习控制.针对重复学习控制的特点,所构造的李亚普诺夫函数不仅与当前参数估计误差有关,也与前一次参数估计误差有关.基于该李亚普诺夫函数,结合Nussbaum类型函数,提出了控制方向未知的系统的重复学习方法.该方法不采用饱和控制,但能保证在闭环系统中跟踪误差在重复区间上一致收敛于零.最后,一个仿真例子说明了该方法的可行性.