1550nm有线电视传输系统在农村网络中的应用

详细阐述利用1550nm有线电视传输系统＂密集广播分配＂的特点,采用FTTLA组网技术建设农村有线电视网络的具体应用,尤其对二级光链路网络指标分配、设计要求做了具体说明,为农村有线电视网络＂村村通＂工程提出一个科学、安全、经济、可靠的设计方案。     

石家庄市有线电视市县网络建设

石家庄市有线电视市县网络采用1550nm模数混合光传输设备,分主、备两路向十八个县广电前端传送市区有线电视网络的50套模拟和20个频点的数字电视信号,用SDH系统传送1550nm光传输设备的网管信息和县（市）数字电视用户管理信息,很好地实现了光传输网络的安全性、可管理性、高性能指标三项设计原则。     

宜昌广电网络“十一五”建设发展设想

宜昌有线电视网络始建1988年，是根据宜昌地理结构、经济发展状况及网络用户需求而建的光纤电缆传输网。1989年采用邻频传输技术建立550M电缆分配系统；1991年采用基带传输技术建立光传输系统；1994年采用调频光传输技术建立星型1310nm光传输体系；2001年采用数据交换技术建成千兆以太网，城区三个机房采用自愈环网结构建立数据传输平台，实现了用光缆、以太、Cahle Modem同轴电缆等多种接入方式进行宽带接入；2002年采用1550nm光传输技术实现宜昌市县有线电视信号联网。经过十几年的不断发展，宜昌广电网络现已成为全国有线电视数字宽带传输网的中继站房，担负国家宽带数字广播电视信息向大西南传输的重要任务；采用SDH传输系统上接湖北省有线网络和国家广电光缆骨干网；采用1550nm传输系统下联当阳、长阳、枝江、秭归、宜都、兴山、五峰、远安等各市、县有线电视网络，县市有线电视用户二十多万户；城区总用户数为二十多万户，城区有线电视用户达到十二万户（不含葛洲坝集团有线电视用户四万多户）。     

WDM技术在有线电视模拟传输中的应用

在有线电视网络的建设中,随着1550nm模拟传输技术日趋成熟,1550nm设备价格不断下浮,在市—镇联网和城市环网建设中被大量采用。我市在97年就采用了1550nm模拟传输技术,实现市—镇联网。既提高了传输质量,又降低了成本。在镇—村有线电视联网中同样可使用1550nm模拟传输技术,主要涉及两方面的问题:一是在市—镇利用     

1550nm改造的经验之谈

自2008年,番禺有线已经率先启动有线电视信号光传输技术1550nm改造项目。经过2年多的改造工作,全区20多个分机房的有线电视信号光传输部分,基本上已经顺利完成从旧有的1310nm光传输技术改造成1550nm光传输技术。1310nm光传输技术与1550nm光传输技术的比较:     

未来的电缆网络

美国的有线电视网已从全部同轴电缆设备发展到今天光纤/同轴电缆混合网(HFC)。这些网络还在继续发展,新的光学纤维、光电子学和1550nm最佳的传输结构,使今天的网络设计人员有了更宽阔的选择范围。这些先进的网络色散较低而传输距离较长,为高级的交互服务传输提供理想的媒体。本文对有线电视传输中光纤技术的应用作一鸟瞰,并探讨未来型的、双向的、现代化网络的前沿技术。     

广播＋窄播传输方案在福州HFC网的应用及系统指标

本文介绍了1550mm广播＋窄播传输方案在福州广电有线电视网双向整合过程中的应用,通过对系统建设方案的分析。以及系统指标的测试对比．指出1550nm广播＋窄播传输方案是广电运营商在城市有线电视网建设和整改中非常有效的一种技术方案,可以达到快速部署、节省成本、便于扩展等目标,从而提高广电网络的竞争力。     

构建面向综合业务的有线电视网

有线电视运营商以互联网业务需求采用的CableModem技术作为数据回传手段，已不能满足宽带数据应用和内容对带宽的需求，没有高性能的双向网络是一直制约有线电视网的信息化发展进程的要素。随着数字电视的发展与推广，有线电视网的数字化和信息化再一次得到关注，新的业务、技术和设备不断涌现，有线电视网发展面临着新的机遇，如何构建面向综合业务的有线电视网将是实现重大突破的基础与方向。从综合业务需求、网络演进、双向接入技术发展以及网络架构设计的角度出发，全面分析了有线电视网的发展趋势，提出了基于有线电视网现状的发展演进的网络架构，这对有线电视运营商的业务发展和网络长远规划具有很强的实践指导意义。     

有线电视网络的发展现状与趋势

双向化改造后的有线电视网络,既是广播电视信号的传输网络,也是宽带业务的承载网络,是有线电视运营商实现业务发展与转型的基础网络.其中有线接入网络是有线电视网络发展的关键,与用户带宽需求和有线接入技术的发展密切相关.通过调研当前国内外有线电视网络的发展现状、有线接入技术及标准的研究进展,分析了有线接入网络的发展趋势,最后对一种自主创新的吉比特同轴接入技术(HINOC)进行了介绍.     

试析有线电视网络双向改造的技术选择

随着科学技术的快速发展和网络信息化时代的进步,人们对于有线电视网络的要求逐渐提高。因此,有线电视网络双向改造将成为网络电视发展的方向。本文通过阐述有线电视双向改造技术的必要性,分析有线电视网络的发展方向,提出有线电视网络双向改造的技术选择,以供参考。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.