移动宽带无线接入技术IEEE 802.16e综述

介绍了实现移动宽带无线接入的关键技术、IEEE802．16e移动无线宽带接入标准及其物理层与MAC层技术，并与IEEE802．20移动无线宽带接入标准进行了简单比较。     

创智专栏宽带接入—缔造未来生活

本介绍了目前几种流行的宽带接入网技术，包括以太网接入技术、光纤入户、XDSL、Cable Modem（电缆调制解调器）技术、宽带无线接入、宽带卫星接入，并对其进行了简单的比较。     

WiMAX及其相关技术

首先介绍了WiMAX技术,然后以IEEE802.16标准为主介绍了其体系结构及关键技术,并且对其它相关的无线宽带接入技术如IEEE802.20,Flash-OFDM技术进行了简单分析和比较.     

基于VDSL及以太网宽带接入的研究

互联网技术不断发展的今天,上网速度的提高以及成为了大多数宽带用户的需求.VDSL和以太网宽带接入技术的相结合,满足了用户对高速宽带接入方式的需求.首先,本文描写了VDSL的特征.其次,简单的对以太网宽带接入做出介绍.最后,提出了基于VDSL及以太网宽带接入的具体研究.     

宽带接入的发展现状及前景

随着网络的发展,宽带日益成为人们工作社交不可或缺的重要工具,而宽带接入技术的不断发展,也直接促进着人类文明的进步。通过对全球宽带接入市场发展情况的分析入手,指出宽带接入的扩展是大势所趋。本文简单概括了目前主流的宽带接入技术,简要分析主流的宽带接入主流技术xDSL,并重点分析介绍了更先进的光纤接入技术将成为主流的原因与遇到的阻力。     

浅谈宽带接入的发展现状及前景

本文通过对全球宽带接入市场发展情况的分析入手，指出宽带接入的扩展是大势所趋。然后进一步阐述了目前世界上比较流行的宽带接入技术概况、技术特点及其目标客户群，说明FTTH是宽带接入的终极技术，是技术发展的必然。接着通过对各种宽带接入技术所占的市场份额及增量的分析得出：xDSL在宽带接入市场的主导地位在短期内不会改变，但FTTH迅速发展是宽带接入的另一热点。最后具体分析了FTTH这一新技术发展的诸多因素和产业链中各个环节，并介绍了FTTH发展的相关政策环境，最后对FTTH的市场前景进行了预测。     

宽带接入网技术及发展

宽带接入网因其所具有的高带宽而成为通信发展的“热点”。当整个通信网向Ｂ－ＩＳＤＮ过渡时，现有通信网的“瓶颈”限制因它的出现而得以解决。本文简单介绍了几种宽带接入网技术（基于铜缆和基于光纤的宽带接入网）的特点，并简单分析了宽带业务的市场前景及宽带接入网的应用前景。     

几种宽带接入技术比较及其应用分析

文章介绍了ADSL、以太网、光纤、无线和Cable Modem等当前主流宽带接入技术，分析了每种技术的特点和具体应用场合，最后对宽带接入技术发展进行了展望。     

浅谈ADSL宽带接入技术及故障处理

本文主要对现今人们上网采用的主流方式:ADSL宽带接入技术,进行简单的介绍,着重对日常生活中我们遇到的常见ADSL宽带故障及解决方法进行了剖析。     

全球宽带接入技术发展分析

本文首先介绍了宽带接入市场的发展现状，然后阐述了宽带接入技术的演进历程，分析了下一代光纤接入技术WDM—PON的发展趋势，最后对金融危机背景下的各国宽带战略进行了探讨。     

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.     

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.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Call for Papers

正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its