基于中国医用体域网频段的物理层方案设计及干扰分析

该文基于中国医疗体域网的专用频段提出了采用扩频的OQPSK调制方案,并在多种干扰的背景下进行分析,仿真结果表明该方案对宽带干扰具有较好的抑制性能,但是由于接收端帧检测算法虚警率较高而对窄带干扰较为敏感。为此提出基于两次延迟自相关的帧检测算法,并验证该算法对宽带和窄带干扰都有较好的抑制性能。该文的研究成果可以为我国无线体域网标准制定提供技术参考,目前该调制方案已被IEEE802.15.4n采纳。     

认知无线电中干扰规避方案的研究

虽然新技术的研发可以提升频谱利用率,但是很多授权频段的频谱利用率却非常低,尤其是信号传播特性好的低频段。认知无线电技术是一种智能的频谱共享技术,可以有效地提高授权频段利用率。文章介绍了认知无线电的关键技术和IEEE 802.22 WRAN标准,通过具体分析无线区域网(WRAN)对数字电视(DTV)接收机造成的干扰,建立了相应的场景模型,提出了有效的干扰规避方案。     

无线体域网技术与节能方案

在无线传感器网络研究中,体域网是当今发展的一大趋势,无论是在远程医疗还是健康监护等领域,都有着非常广阔的市场前景。无线体域网的应用,能够有效缓解看病贵、看病难的问题,对医学的发展有着至关重要的意义。本文主要以无线体域网技术分析作为出发点,进而探讨其节能方案,希望给我国医学领域带来一定帮助。     

无线体域网(1)

无线体域网是个人健康信息采集与传输的重要技术手段之一,具有重要现实意义和产业化前景,受到工业界、学术界和标准化组织的广泛关注。另外,IEEE 802.15.6协议标准是目前国际上公认的一款适用于健康信息采集的未来超短距无线体域网协议标准。讲座将分3期对该技术进行介绍:第1期讲述无线体域网的背景、研究动态和技术特征;第2期对无线体域网的频段选取、信道建模、MAC层协议、通信技术和数据处理技术特征进行介绍;第3期介绍无线体域网的节点设计、数据采集和应用场景的相关问题。     

无线体域网

无线体域网是个人健康信息采集与传输的重要技术手段之一,具有重要现实意义和产业化前景,受到工业界、学术界和标准化组织的广泛关注。另外,IEEE 802.15.6协议标准是目前国际上公认的一款适用于健康信息采集的未来超短距无线体域网协议标准。讲座将分3期对该技术进行介绍:第1期讲述无线体域网的背景、研究动态和技术特征;第2期对无线体域网的频段选取、信道建模、MAC层协议、通信技术和数据处理技术特征进行介绍;第3期介绍无线体域网的节点设计、数据采集和应用场景问题。     

无线体域网(3)

无线体域网是个人健康信息采集与传输的重要技术手段之一,具有重要现实意义和产业化前景,受到工业界、学术界和标准化组织的广泛关注。另外,IEEE 802.15.6协议标准是目前国际上公认的一款适用于健康信息采集的未来超短距无线体域网协议标准。讲座将分3期对该技术进行介绍:第1期讲述无线体域网的背景、研究动态和技术特征;第2期对无线体域网的频段选取、信道建模、MAC层协议、通信技术和数据处理技术特征进行介绍;第3期介绍无线体域网的节点设计、数据采集和应用场景问题。     

移动数字多媒体广播的研究进展

传统广播电视存在业务质量较差．业务单一等缺点．数字化已经成为传统模拟音视频广播发展趋势和出路。本文简要回顾了数字无线广播的发展历程，给出适用于30MHz-3000MHz频段的数字音频广播DAB系统结构。基本参数和复用机制。在介绍目前已有的地面与卫星移动多媒体广播系统的基础上．分析和比较了不同地面移动多媒体广播系统多个方面的性能．并展望了移动多媒体广播技术的下一步发展。     

L频段天地一体数字多媒体广播技术在交通综合信息服务领域的应用

本文根据国内道路交通发展状况,在卫星数字多媒体广播技术与地面移动数字多媒体技术基础上,提出应用L频段天地一体数字多媒体广播技术,可在我国的交通综合信息服务领域发挥重要的作用     

CMMB运营未来发展探讨

1CMMB天地一体覆盖全国CMMB的行业标准规定了在广播业务频率范围内,移动多媒体广播系统广播信号传输信号的祯结构、信道编码和调制,该标准使用于在30MHz和3000MHz频率范围内的广播业务频率,通过卫星和地面无线发射电视、广播、数据信息等多媒体信号的广播系统,可以实现全国漫游,传输技术采用STiMi技术。     

民航雷达频段干扰查找

随着通信技术的不断发展,生活周边的无线信号变得越来越多样化,并且也越来越复杂化。而在这种情况下,民航的雷达频段信号将受到这些无线信号的干扰,继而无法为飞机的正常飞行提供应有的保障。所以,只有采用一些雷达频段干扰查找技术进行这些干扰源的查找,才能排除民航运行的安全隐患。基于这种认识,文章对雷达频段干扰查找技术进行了分析,以便对民航雷达频段干扰查找问题进行研究,继而为关注这一话题的人们提供参考。     

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.