接入网技术在兖矿宽带社区中的应用

随着互联网技术的迅猛发展和人们对网络的依赖,传统的拨号上网已远远不能满足用户需求,宽带走入百姓家庭已是大势所趋,兖矿电信为满足矿区用户需求,结合社区实际,大力构建兖矿宽带社区,取得了显著成效。     

HFC接入Internet的技术分析

本文介绍了HFC的基本概念,分析了HFC网络,阐述了HFC接入的方式。     

Analysis based on EU Regulation No 517/2014 of new HFC/HFO mixtures as alternatives of high GWP refrigerants in refrigeration and HVAC systems

The EU Regulation No 517/2014 is going to phase-out most of the refrigerants commonly used in refrigeration and air conditioning systems (R134a, R404A and R410A) because of their extended use and their high GWP values. There are very different options to replace them; however, no refrigerant has yet imposed. In this paper we review and analyze the different mixtures proposed by the AHRI as alternative refrigerants to those employed currently. These mixtures are composed by HFC refrigerants: R32, R125, R152a and R134a; and HFO refrigerants: R1234yf and R1234ze(E). It is concluded, from the theoretical analysis, that most of the new HFO/HFC mixtures perform under the HFC analyzed (although some experimental studies show the contrary) and, in most cases, do not meet the GWP restrictions approved by the European normative. Furthermore, some of the mixtures proposed would have problems due to their flammability.     

三网融合技术值得注意的几个问题

三网融合正在积极推进,其技术选择受到各方关注,为此而探讨几个主要问题：借助三网融合,展开适度竞争,有利于改善我国的网络环境,有线电视业参与三网融合竞争的基本条件;非对称DOC-SIS/HFC网络结构更有利于三网融合增值业务开发,Cable Modem和ADSL是当前宽带接入的主流技术,Cable Modem接入技术将在宽带市场竞争中胜出,而EPON＋EoC并非网络双向改造的最佳方案。针对有关的指导性文件,阐述相对固定的信道带宽更有利于有线电视联网和用户接入,提出两种技术与经济效益更好的方法,以增加传输容量,较8n（MHz）方式变更信道带宽更先进更合理。     

CMTS+CM接入方式同时实现VPN与非VPN业务的方案

广西广电数据网是全省统一的多业务数据平台.接入方式以CMTS+CM为主.基于CMTS+CM接入方式,利用HFC网络实现VPN和非VPN的业务,从而实现了对专网业务的支持.本文简单描述了网络架构、设备性能,详细说明实现方案,对路由器、CMTS和支撑系统进行配置,实现了VPN和非VPN业务,并完成测试.测试结果表明通过CMTS+CM的接入方式可以实现VPN和非VPN业务;实现VPN与非VPN之间、VPN与VPN之间的隔离,实现非VPN内互通及同一VPN内互通;并可以与以太网接入方式灵活组网.     

C-DOCSIS系统中CMC设计与实现

针对我国"三网融合"的不断推进,广电运营商提供数据接入的需求,介绍了在HFC中应用前景广泛的C-DOCSIS技术。阐述了C-DOCSIS系统中CMC（Cable media converter）设备的硬件设计思路与方法。经验证此设计方案具有高度的可靠性和稳定性,在HFC网络中得到了良好的应用。     

HFC回传通道的统计评估方法及实际应用

介绍如何对HFC网络回传通道的监测数据进行统计、分析,从而进一步评估网络状况,对运营商的宽带建设、维护和运营有非常实际的意义。     

有源 EoC 系统分析与测试方法研究

EoC 技术是目前基于广电 HFC 网络实现三网融合的最佳接入技术之一,如何来评估及检测 EoC 产品的性能是本文主要解决的问题.本文以主芯片为 SPC -200C 的 HomePLUG BPL 方案 EoC 产品为测试基础,着重阐述了 EoC 产品的全方位性能测试新方法,以便能够为广电运营商提供一种 EoC 产品的测试及检测新手段.     

Use of nanoparticles to make mineral oil lubricants feasible for use in a residential air conditioner employing hydro-fluorocarbons refrigerants

The application of nano-fluids in refrigerating systems is considered to be a potential way to improve the energy efficiency and reliability of HVAC&R facilities and to make economic the use of environment-friendly refrigerants. In this paper, we report a method that uses nanoparticles to enhance the energy efficiency of retrofitted residential air conditioners (RAC) employing HFCs as alternative refrigerants. The reliability and performance of RAC with nanoparticles in the working fluid have been investigated experimentally. A new mineral-based nano-refrigeration oil (MNRO), formed by blending some nanoparticles (NiFe₂O₄) into naphthene based oil B32, was employed in the RAC using R410a as refrigerant. A method showing how to disperse the NiFe₂O₄ nanoparticles in the mineral oil refrigeration lubricants is presented together with an investigation of their stability. The solubilities of the new MNRO in R134a, R407C, R410a and R425a were measured. The performances of the RAC, such as the cooling/heating capacity, the power input and the energy efficiency ratio, were determined. The results indicate that the mixture of R410a/MNRO works normally in the RAC. The cooling/heating EER of the RAC increased about 6% by replacing the Polyol-Easter oil VG 32 lubricant with MNRO.     

多媒体宽带接入网分析

本文分析了多媒体宽带接入网现有的几种入网络各自的特点，并比较了它们的优缺点，提出了相应的实现方案。