含扭带管内液压油流动与传热实验研究

针对几种常见液压油在不同扭率的含扭带管内的流动与传热特性进行了实验研究,得出了液压油在含扭带管中层流的摩擦系数及对流放热系数的准则关系式,并将实验结果与光管时的摩擦系数及对流放热系数对比,结果表明,扭带在扭率１．９２～２１．０５范围内均可强化液压油的层流对流换热过程．     

转向管柱扭转形变检测的实现

本文针对转向管柱的形变特征,设计了一套机电一体化系统。系统用高精度蜗轮蜗杆实现力矩加载,通过力传感器、角度编码器和PCL-818数据采集卡,获取力及其对应的形变量,实验数据经误差处理后分析保存,从而达到监测管柱扭转形变的主要目的。该装置测量精准度高,实时性好,且机械的设计较为灵活,可广泛用于各种相类似产品和装置的质检过程。     

螺旋扁管在油冷却器中的污垢特性实验研究

对螺旋扁管与普通直管在油冷却器中的污垢特性进行了对比实验研究。实验采用φ19×2的普通直管和由同种直管制成的螺旋扁管,螺旋扁管导程分别为130mm、180mm和230mm。通过实验,研究了Re和螺旋扁管导程对污垢特性的影响。结果表明,随着导程减小,螺旋扁管污垢热阻减小。在Re≤1500情况下试验用螺旋扁管的污垢特性与光管相近。随着Re增大,污垢热阻都减小,但螺旋扁管的减小速度更大。当Re≥10000时,螺旋扁管污垢热阻约为光管的1/2～1/4。     

内置偏心多螺旋扭带换热管的传热特性研究

通过数值模拟对内置偏心多螺旋扭带换热管的传热特性进行了计算与分析,结果表明:换热管的对流传热强度随着扭带数量的增加而提高,随着扭带扭率的减小而提高。流动阻力损失相对于空管有很大程度的提高。传热性能评价指标在湍流时普遍较低,故多螺旋扭带换热管的使用应考虑流动阻力损失的影响。     

内插松弛扭带波节管的流动与传热特性的数值模拟

采用RNG k-ε数值模拟方法研究一种新型内插松弛扭带波节管（CLT）的流动与传热特性。将数值模拟结果与自建实验台的实验结果进行了对比验证;比较了CLT和内插松弛扭带光管（SLT）的传热性能差异;考察了CLT中扭率和余隙比对流动和传热特性的影响规律。研究结果表明CLT相比于传统的SLT,传热性能最多提高1.17倍,综合传热性能的绝对数值最多增加0.15。CLT的综合传热性能随着扭率的增加而增加,而增加的幅度却逐渐减小,高Reynolds数时减小的程度更加显著。同时,综合传热性能随着余隙比的增大而降低并且降低的幅度也逐渐减小,在低Reynolds数时明显降低,而在高Reynolds数时略微降低。综合考虑,低Reynolds数时应该选择余隙比低的扭带,而高Reynolds数时则应选择余隙比高的扭带。     

THE PHASE WEB PARADIGM

We describe an information-oriented, computational physical theory based on expressing knowledge of the world via patterns of synchronization. The systems this theory describes are self-organizing, display emergent phenomena, and can be expressed in terms both of Clifford algebras and algebraic topology, and practical running programs.     

Vertex-pancyclicity of twisted cubes with maximal faulty edges

The n-dimensional twisted cube, denoted by TQ _n , a variation of the hypercube, possesses some properties superior to the hypercube. In this paper, we show that every vertex in TQ _n lies on a fault-free cycle of every length from 6 to 2 ⁿ , even if there are up to n?2 link faults. We also show that our result is optimal.     

甚高速数字用户线VDSL技术

VDSL是正在发展中的利用现有铜双绞电话线传输宽带数据的新技术。本文对其容量、结构、支撑技术、标准化现状、与ADSL的关系等进行了介绍。     

Force control of twisted and coiled polymer actuators via active control of electrical heating and forced convective liquid cooling

For decades, numerous artificial muscles have been proposed in order to implement beneficial features of biological muscles into robotics. Unfortunately, traditional artificial muscles experienced difficulties in imitating properties of the biological muscles due to mechanical and control issues. Recently, twisted and coiled polymer actuators (TCP) have been shown to produce large mechanical power via thermal stimulations and strong linearity. In this paper, a high-performance TCP thermally cycled by electrical heating and forced convective liquid cooling is designed and associated control algorithms are presented. We elaborate the model of the TCP that is simple, yet provides insight into how the electrical heating and the forced convective liquid cooling contribute to the TCP actuation. The proposed model is verified by experimental studies. Based on the proposed model, we design a feedforward–feedback controller and switching laws, which actively control the TCP in both the heating and cooling cycles. Furthermore, we extend our control methodology to agonist–antagonist TCPs. From the experimental studies, the proposed method is shown to be effective in both single TCP and antagonistic TCPs.     

Node-pancyclicity and edge-pancyclicity of hypercube variants

Twisted cubes, crossed cubes, Möbius cubes, and locally twisted cubes are some of the widely studied hypercube variants. The 4-pancyclicity of twisted cubes, crossed cubes, Möbius cubes, locally twisted cubes and the 4-edge-pancyclicity of twisted cubes, crossed cubes, Möbius cubes are proven in [C.P. Chang, J.N. Wang, L.H. Hsu, Topological properties of twisted cube, Inform. Sci. 113 (1999) 147-167; C.P. Chang, T.Y. Sung, L.H. Hsu, Edge congestion and topological properties of crossed cubes, IEEE Trans. Parall. Distr. 11 (1) (2000) 64-80; J. Fan, Hamilton-connectivity and cycle embedding of the Möbius cubes, Inform. Process. Lett. 82 (2002) 113-117; X. Yang, G.M. Megson, D.J. Evans, Locally twisted cubes are 4-pancyclic, Appl. Math. Lett. 17 (2004) 919-925; J. Fan, N. Yu, X. Jia, X. Lin, Embedding of cycles in twisted cubes with edge-pancyclic, Algorithmica, submitted for publication; J. Fan, X. Lin, X. Jia, Node-pancyclic and edge-pancyclic of crossed cubes, Inform. Process. Lett. 93 (2005) 133-138; M. Xu, J.M. Xu, Edge-pancyclicity of Möbius cubes, Inform. Process. Lett. 96 (2005) 136-140], respectively. It should be noted that 4-edge-pancyclicity implies 4-node-pancyclicity which further implies 4-pancyclicity. In this paper, we outline an approach to prove the 4-edge-pancyclicity of some hypercube variants and we prove in particular that Möbius cubes and locally twisted cubes are 4-edge-pancyclic.