高可靠性远程数据传输系统设计

针对飞行器系统测试设备研制的要求,设计了一种基于LVDS串行/解串器架构的远程数据传输系统;系统包括远程数据传输模块和电流/电压信号转换模块,采用双绞线传输与普通并行线传输相结合的方式,实现远程数据传输的功能;系统采用FPGA作为主控芯片,使用电缆驱动芯片和自适应电缆均衡器来增强双绞线驱动能力,使用电流环信号传输方式代替电压信号传输方式来增加低速信号的抗干扰能力,同时对PCB布板和系统软件做可靠性优化设计,大大提高了该系统在恶劣使用环境下远距离数据传输的可靠性;目前该系统可以在恶劣电磁环境下以176Mbps的单线波特率在47米实验双绞电缆上实现无误码数据传输。     

Independent spanning trees vs. edge-disjoint spanning trees in locally twisted cubes

Fault-tolerant broadcasting and secure message distribution are important issues for numerous applications in networks. It is a common idea to design multiple spanning trees with a specific property in the underlying graph of a network to serve as a broadcasting scheme or a distribution protocol for receiving high levels of fault-tolerance and of security. A set of spanning trees in a graph is said to be edge-disjoint if these trees are rooted at the same node without sharing any common edge. Hsieh and Tu [S.-Y. Hsieh, C.-J. Tu, Constructing edge-disjoint spanning trees in locally twisted cubes, Theoretical Computer Science 410 (2009) 926-932] recently presented an algorithm for constructing n edge-disjoint spanning trees in an n-dimensional locally twisted cube. In this paper, we prove that indeed all spanning trees constructed by their algorithm are independent, i.e., any two spanning trees are rooted at the same node, say r, and for any other node v≠r, the two different paths from v to r, one path in each tree, are internally node-disjoint.     

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.     

Cold Modelling of Slag Splashing in LD Furnace by Oxygen Lance with Twisted Nozzle Tip

The effects of a conventional lance tip with 4 normal nozzles and a lance tip with 4 twisted nozzles on slag splashing were investigated. A cold model for LD converters, Jiuquan Iron & Steel Co., was established and the amount of slag splashed onto the model walls was measured in the cold modelling experiments. The results from the experiments show that at low top gas flow rate the amount of slag splashing for the tip with twisted nozzles is less than that for the conventional tip, whereas at high top gas flow rate the amount of slag splashing for the nozzle twisted lance is greater than that for the conventional lance. For the nozzle twisted lance tip, slag splashing rates increase with increase in slag amount, lance height and top gas flow rate and the maximum amount of slag splashing for the tip with twisted nozzles can be obtained under the process parameters of 47.6 Nm³/h gas flow rate, 12% slag amount and 247 mm lance height. More slag droplets can be directed onto the cone with a nozzle twisted lance tip than with a normal lance tip at high top gas flow rate.     

扭余模代数的一些性质

主要研究了右H-余模代数上的扭的卷积性质，对τ能够作成Hopf代数的扭的充分必要条件，以及扭作用对左H-模代数和右H-余模代数A的结构产生的影响进行了深入探讨。通过严密的推理验证，得出了扭作用的卷积仍旧是扭作用；给出了τ作成Hopf代数(H，△)的扭作用的充分必要条件；证明了(A^H)^τ=(A^τ)^H，(A^coH)^τ=(A^τ)^coH；主要证明了扭的卷积仍是扭，并进一步研究了Hopf代数以及作为左H-模代数和右H-余模代数A的扭性质。     

Accurate low complexity modeling of twisted pairs suitable for G.fast frequencies

As the higher and higher frequency bands of existing metallic cables in access networks are being continuously exploited by modern transmission technologies, such as the G.fast, the necessity of providing accurate and suitable modeling of their transmission characteristics is evident. Therefore, this paper is focused on modeling of a propagation constant of twisted pairs and metallic cables at high frequencies up to 250 MHz, and an innovative arsinh model is proposed and described. This new model is based on an idea of adopting inverse hyperbolic sine function for modeling of both secondary line coefficients, attenuation constant and phase constant, and its main motivation is to provide their accurate estimations for G.fast frequencies up to 250 MHz for various types of metallic cables while maintaining a low computational complexity. The proposed model was compared with numerous characteristics measured for various real metallic cables as well as with several existing models in order to illustrate its potential. The results, which are presented within this paper, clearly illustrate that the proposed arsinh model generally outperforms existing standard models based on the equal number of required parameters. Copyright © 2015 John Wiley & Sons, Ltd.     

捻系数和毛羽值与棉纱强力的相关性分析

通过测试得到环锭纺棉纱的捻度、毛羽值和断裂强力的数据。对数据进行回归分析，结果显示：棉纱的捻系数和毛羽值对断裂强力的影响显著；而且毛羽值与断裂强力之间的关系可以用三次项模型描述。     

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.     

Model of a polymer chain twisted inside a statistical segment. Poly(3‐hexylthiophene) in chloroform solutions

A set of hydrodynamic methods in extremely dilute solutions (determination of intrinsic viscosity [η ], translational diffusion D and flotation in a centrifugal field s ) was used in the studies of conformational properties, dimensions and equilibrium rigidity of individual molecules of a series of samples of poly(3‐hexylthiophene). Absolute molecular masses M _sD were determined. The Mark–Kuhn–Houwink equations for the range of M _sD from 2240 to 15 300 g mol^?1 are given. For the first time, an analysis of conformational properties and equilibrium flexibility of poly(3‐hexylthiophene) molecules was carried out using the model of a statistical segment containing a twisted polymer chain. © 2017 Society of Chemical Industry     

冷轧螺纹钢筋的力学性能研究

介绍了冷轧螺纹钢筋的轧制原理,从屈服强度、抗拉强度、延伸率、冷弯条件等方面说明了冷轧螺纹钢筋力学性能标准(新技术的生产工艺),研究了冷轧螺纹钢筋的力学性能及其影响因素。