Experimental investigation of varying composition of HCNG on performance and combustion characteristics of a SI engine

With rapid depletion of petroleum resources, researchers are investigating alternate fuels to meet global transportation energy demand. Gaseous fuels such as compressed natural gas (CNG) and hydrogen are of special interest because of their cleaner combustion characteristics compared to liquid petroleum based fossil fuels. However both these gaseous fuels have some technical issues when they are used as stand-alone alternate fuel in conventional spark ignition (SI) engines. CNG suffers from lower energy density and narrow flammability range whereas backfiring tendency is highly pronounced in hydrogen fueled engines. Hydrogen enriched compressed natural gas (HCNG) mixtures are observed to be good alternative to these individual fuels since these mixtures do not pose the issues experienced by the constituent fuels i.e. CNG and hydrogen. In this study, experiments were conducted in a spark ignited gas engine using various compositions of HCNG mixtures having 0, 10, 20, 30, 50, 70 and 100% (v/v) hydrogen fraction. The performance and combustion characteristics of these test fuels were compared with that of baseline CNG, in order to find an optimum HCNG mixture composition for a single cylinder gas engine. Results obtained showed that 30HCNG mixture delivered superior engine performance compared to other HCNG mixtures and baseline CNG, which is in sharp contrast to 15HCNG being advocated globally.     

七号信令网IP化的演进分析

本文首先介绍了七号信令网的发展方向,并对3G网络中的信令进行了分析,由此引出IP信令网的概念.之后对IP信令网的协议及目标网结构进行了阐述,并结合中国移动现有信令网的情况,提出了IP信令网的引入方案.     

STP协议实验测试与仿真测试的比较和研究

为确保计算机网络在网络故障发生时具有生存及恢复能力,需要选择并且测试相关处理故障的正确协议.这些测试如果采用现实的网络设备以及环境,所得出的结果无疑是很可靠的.但受设备和时间所限,这样的测试并不总是可行的.因此本文用仿真环境来模拟实验环境进行测试,然而仿真环境也不是总能模拟真正的网络行为.本文分别采用两种测试方法对STP协议和RSTP协议中的收敛时间进行测试比较,测试从简单的拓扑开始,并最终在仿真环境中实现在实验环境中很难实现的大型拓扑的测试.     

屏蔽双绞线在电力机车上的应用研究

针对电力机车上不同设备和子系统之间的电磁兼容问题,分析屏蔽双绞线的抗电磁干扰机理;对屏蔽层不同端接方式进行了测量,并对测试数据进行分析,得出屏蔽层合理端接方式。最后给出了一个应用于机车车辆的实例。     

以太网上实时业务服务质量保证策略的研究

首先分析了以太网上相关技术的进展,并指出了以太网上保证实时业务服务质量的迫切性,然后提出了以太网上保证实时业务服务质量的策略,并给出了该策略的实现结构。仿真验证了我们提出的策略对实时业务服务质量的保证是有效的。     

S12No.7信令转接点

信令转接点作为七号信令网的关键设备，在我国信令网的建设中起着至关重要的作用。本文着重介绍了大量运用于国家网的Ｓ１２独立令令转接点的结构、性能特点和应用。     

Stability of Nonlinear Feedback Shift Registers with Periodic Input

The stability of Non-Linear Feedback Shift Registers (NFSRs) plays an important role in the cryptographic security. Due to the complexity of nonlinear systems and the lack of efficient algebraic tools, the theorems related to the stability of NFSRs are still not well-developed. In this paper, we view the NFSR with periodic inputs as a Boolean control network. Based on the mathematical tool of semi-tensor product (STP), the Boolean network can be mapped into an algebraic form. Through these basic theories, we analyze the state space of non-autonomous NFSRs, and discuss the stability of an NFSR with periodic inputs of limited length or unlimited length. The simulation results are provided to prove the efficiency of the model. Based on these works, we can provide a method to analyze the stability of the NFSR with periodic input, including limited length and unlimited length. By this, we can efficiently reduce the computational complexity, and its efficiency is demonstrated by applying the theorem in simulations dealing with the stability of a non-autonomous NFSR.     

基于STP模型的“超级网银”产品策略探析

在介绍STP模型和＂超级网银＂的基础上,运用STP模型对＂超级网银＂在市场细分、目标市场和市场定位三个方面进行分析,并在此基础上分别从业务、操作、设置、安全、页面、协议六个纬度重点阐述＂超级网银＂的产品策略。     

基于VaIgrind中间语言的测试用例动态生成

软件漏洞是软件在设计实现时由于软件功能自身的复杂性和抽象性,导致在具体实现时所引起的缺陷。测试用例在检测软件缺陷时能够起到指导作用,在研究VaIgrind中间语言的基础上,针对STP求解器的语言特点,设计实现了一个测试用例动态生成的系统,对其中的主要设计思想进行了阐述,并对该系统进行了程序测试,对最终的测试性能给出了结果。     

一种新型工业以太网拓扑结构发现方法*

在分析网络层和数据链路层拓扑发现的区别的基础上,提出了一种基于SNMP和STP的分层工业以太网网络拓扑结构图发现算法。实验结果表明：与传统的算法相比,该算法对网络流量的影响更小,具有较低的复杂度和良好的可扩展性。