基于SDH传输网的同步时钟系统在电网中的应用

同步网是通信网络运行的支撑系统之一,它为各类通信设备的时钟提供同步控制信号,使网内设备时钟工作在共同的频率上,从而消除或减少误码、滑码。文章结合河北南网实际情况,以现有SDH传输网作为载体,提出混合同步方式组织同步时钟网络及其地面定时链路的设计方案,并在实际工程中得到应用。     

浙江电力通信骨干同步网改造探讨

针对国网浙江电力通信骨干同步网现状中存在的定时基准链路组织不完善、备用时钟链路不可靠、过度依赖GPS卫星信号作为定时基准以及网管功能不全面等方面的问题,从同步网络组织优化和统一网络管理上提出一套切实可行的改造方案,并提出省级频率同步网建设中应遵循的组网原则和策略.     

同步支撑网系统的建设--运营商网络优化和服务质量快速提高之道

同步网是电信三大支撑网之一,由节点时钟和传递同步定时信号的同步链路构成。其作用是准确地将同步定时信号从基准时钟传送到同步网的各节点,调整网中的各时钟并保持信号同步,满足通信网传输性能和交换性能的需要。     

电信网同步质量评估

数字传输继续向更高的比特率发展，网络的基本拓扑结构正的从点到点向环路和链路发展，网络的可靠性是最根本的，没有可靠的网络基础。通信网就不能发展，同步网时钟漂移会引起误码、滑码、数据丢失干扰，从而严重降低ＳＤＨ传输质量。指示器分析法、漂移分析法、同步漂移传真３种测试可以判断是否存在时钟同步问题，评估时钟的同步质量以及网元对相位漂移的随力，把握测试时间寺点和方法是测量同步质量的关键。     

动态搜索

大唐电信中标上海电信 同步网工程 近日,大唐电信和上海电信公司签署协议,由大唐电信为上海电信通信网提供优良的网络同步支撑服务。数字同步网是现代通信网的一个必不可少的重要组成部分,能准确地将同步信息从基准时钟向同步网内各同步节点传递,从而调节网中的时钟以建立并保持同步,满足电信网传递业务信息所需的传输和交换性能要求,是保证网络定时     

运营商网络优化和服务质量快速提高之道：同步支撑网系统建设

同步支撑网概述 1.同步支撑网的概念 同步网是电信三大支撑网之一，由节点时钟和传递同步定时信号的同步链路构成。其作用是准确地将同步定时信号从基准时钟传送到同步网的各节点，调整网中的各时钟并保持信号同步，满足通信网传输性能和交换性能的需要。随着电信业务日益丰富多彩，用户需求的宽带化和个性化，越来越复杂的通信系统对同步支撑网提出了更高的要求。     

通信系统同步网的发展及应用

时钟同步网是通信网络的关键基础设施，为移动、语音、客户组网型专线等各类业务提供频率和时间地面同步服务，起着重要的支撑作用。介绍了同步网技术及网络发展演进，阐述了通信系统同步网演进的必要性，结合现有同步网的现状详细分析同步网的应用，主要是研究网络结构的组建、设备部署、设备连接方案、同步源选择方案等。     

5G高精度时间同步组网方案研究

5G网络部署和垂直行业应用对时间同步提出了新的需求。为了满足高精度的同步需求,需要采用高精度同步源技术、高精度同步传送技术、同步监测技术、智能时钟部署及运维技术。针对OTN系统和SPN系统同步网部署分别提出了典型的方案,为5G同步网的规划建设提供了参考。     

同步网在数字化油田建设中的应用

数字同步网是现代通信网的一个重要的组成部分,能准确地将同步信息从基准时钟向同步网各同步节点传递,从而调节网中的时钟以建立并保持同步,它是保证网络定时性能的关键。因节点时钟是通信设备（主要是交换设备）的一部分,当进行涉及时钟的操作时,有可能影响同步网的运行,因此,有必要在同步节点或通信设备较多的情况下,在通信网的重要枢纽上单独设置时钟系统,承上启下,沟通整个同步网,     

福建省数字同步网定时传送方案的探讨

福建省现有数字同步网(见图1)采用3级结构的主从同步方式,定时链路组织主要基于准同步数字系列(PDH)传送方式。第一级是福州枢纽的区域基准时钟(LPR),第二级是各地市中心局的二级节点从时钟(SSU-T)和各地市重要汇接局的二级节点从时钟(SSU-L),第三级是各地市汇接局和端局的三级节点从时钟。其中,福州枢纽作为省数字同步网的LPR,既能与全球定位系统(GPS)同步,又能与北京和武汉的全国基准主时钟(PRC)同步。该省数字同步网中的其他所有同步供给单元(SSU)都能直接或间接地同步于福州枢纽的LPR。本文主要讨论地市中心局的二级从时钟…     

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.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.