Productivity Change and Growth in Posts and Telecommunications Sector

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NGN and Softswitch

he International Telecommunication Union (ITU) kicked off the study of Next Generation Network (NGN) from its 2001-2004 study period. In 2003, it issued the draft Recommendations of NGN framework, and held global NGN workshops. In 2004, it held the meeting of Joint Rapporteur Group on NGN, and set up the Focus Group on Next Generation Networks (FGNGN). World Telecommunication Standardization Assembly (WTSA-04) declared the setting up of the Study Group of ITU Telecommunicati…     

MPEG-Past and Future

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Status and Trends in Advanced SOI Devices and Materials

提供了一种用于安德鲁反射测量样品制备新方法.该方法采用聚焦粒子束刻蚀和磁控溅射,可以获得可控的、干净的、无应力的纳米接触用于自旋极化探测.所制备的样品中,磁性和非磁性材料样品的反射谱都表现出复杂的峰和谷结构,这些结构可能源于与界面相关的零偏压反常以及与激发态相关的准离子相互作用.对另一个Co40Fe40B20合金样品采用简单的钕针尖压针方法进行了对比性测量,反射谱中没有观察到谷结构,但谱结构出现较明显的热扩展,这种热扩展可能来源于界面处的非弹性输运.所有的反射谱目前还不能由现有的理论给出令人满意的解释.利用点接触反射方法获得可靠的自旋极化信息还有赖于接触界面特征的进一步分析.而一个更切合实际的、更完善的理论成为迫切的需要.     

Millimeter Wave and Terahertz Communications： Feasibility and Challenges

In this paper, the challenges with and motivations for developing millimeter wave and terahertz communications are described. A high-level candidate architecture is presented, and use cases highlighting the potential applicability of high-frequency links are discussed. Mobility challenges at these higher frequencies are also discussed. Difficulties that arise as a result of high carrier frequencies and higher path loss can be overcome by practical, higher-gain antennas that have the added benefit of reducing intercell interference. Simulation methodology and results are given. The results show that millimeter wave coverage is possible in large, outdoor spaces, and only a reasonable number of base stations are needed. Network throughput can exceed 25 Gbit/s, and cell-edge user throughput can reach approximately 100 Mbit/s.     

High Purity and Large-scale Preparation of β-Ga2O3 Nanowires and Nanosheets by CVD and Their Raman and Photoluminescence Characteristics

Ga2O3 nano-structures, nanowires and nanosheets are produced on Au pre coated（111） silicon substrates with chemical vapor deposition（CVD） technique. By evaporating pure Ga powder in the H2O atmosphere under ambient pressure the large-scale preparation of β-Ga2O3 with monoclinic crystalline structure is achieved. The crystalline structures and morphologies of produced Ga2O3 nano-structures are characterized by means of scanning electron microscope（SEM）, X-ray diffraction（XRD）, selected area electron diffraction （SAED） and transmission electron microscope（TEM）. Raman spectrum reveals the typical vibration modes of Ga2O3 The vibration mode shifts corresponding to Ga2O3 nano-structures are not found. Two distinguish photoluminescence（PL） emissions are found at about 399 nm and 469 nm owing to the VO-VGa excitation and VO-VGaO excitation, respectively. The growth mechanisms of Ga2O3 nanowires and nanosheets are discussed with vapor liquid-solid（VLS） and vapor-solid（VS） mechanisms.     

AFM and XPS Study on the Surface and Interface States of CuPc and SiO2 Films

利用热生长工艺和热蒸发方法分别获得CuPc和SiO2薄膜层,通过原子力显微镜和X射线光电子能谱对其表面界面电子状态进行了研究,并采用高斯拟合方法对各谱进行了详细分析.结果表明,在氧原子的作用下,N1s,C1s,O1s 和Cu2p都经受了一定的化学位移,从而使得各原子间的相互作用强度有所改变,这是导致OFET性能劣化的重要原因之一.对OFET而言,采用溅射工艺制备的SiO2层应比热氧化生长的SiO2层更合适.     

Growth and Optical Properties of ZnO Films and Quantum Wells

研究了用MOCVD法在蓝宝石(Al2O3)(0001)和(1120)衬底上制备ZnO薄膜时的生长特性.详细研究了采用Al2O3(0001)衬底时生长温度与压力的影响.由于存在比较大的晶格失配,一般容易得到ZnO纳米结晶,不容易获得既平坦且质量又好的ZnO薄膜.生长温度对薄膜-衬底界面的生长模式有很大的影响;而生长压力对ZnO纳米结晶的形状有决定性作用.通过适当控制生长温度及压力,可以得到ZnO薄膜或不同形状的纳米结构.当采用Al2O3(1120)衬底时,由于晶格失配较小,能保持平坦层状生长,临界膜厚远远大于采用Al2O3(0001)衬底的结果.在Al2O3(1120)衬底上制作了ZnO/MgZnO量子阱并研究了其光学特性.观察到了量子化能级间以及在载流子间的跃迁引起的发光.由压电效应引起的内建电场约为3×105V/cm.同时发现采用低温低压生长可以增大ZnO中受主杂质浓度,有利于获得p型ZnO.     

Laser Technology and Equipment

Beijing JCZ Technology CO., LTDProduct:Laser Marking Software Model: Ezcad2.0 Features:Low cost, high quality, intuitive, easy to learn and easy to use;internationalized interface will display any language; extended- axis motor control used for rotary axis, x - y tables, etc. Control external equipment with built- in I/0 objects;import files such as PLT,DXF,AI,DST,BMP,JPG,GIF,TGA,PNG,TIF, TIFF, etc;add Barcode 2 of 39, 128, 93, DataMa- trix, CodaBar, UPC, EAN, PDF417; …     

Optical Instruments and Components

Beijing Optical Instrument PlantProduct:High- precision Motorized Rotating Stage Model: MRS211 Specifications:Accuracy:2″, grating index dial, liquid crystal display. Product:High- precision Motorized Translation Stage Model: MTS317 Specifications:Stroke 400, linear slide block+ball guide screw(precision). Product:High- accuracy Motorized Translation Stage Model: MTS603 Specifications:Stroke 150, linear slide block (high- ac- curacy).Product:Precision Motorized Tilting Stage M…     

Current Status and Trend of Internet and E-Commerce Market in Korea

After the remarkable increase of Internet users and broadband Internet subscribers at the end of the 20th century, the size of Korean Internet and e-commerce market steadily increased but the growth rate has been either stagnant or decreased. Trends of Korean Internet and e-commerce market are summarized in this paper the trends on Internet usage are introduced. Trends of online games, blogs and wireless Internet are introduced. The trends of Korean Internet market may have implications for China and Japan.     

Laser Technology and Equipment

GK Laser Technology Co.,Ltd. Product:5W CW Diode-Pumped Solid-State Green Laser Model: AmberGreen-5000 Specifications:Wavelength:532nm,Output power: >5W, Beam quality: M2 <3,Beam diameter: 1.5mm,Divergence: <3mrad,Power stability: <2% over 8h,Power supply: 220V 50Hz AC,Cooling: Air cooling (TEC). Product: QCW Diode-Pumped Solid-State Green Laser     

Laser Technology and Equipment

Laser Technology and EquipmentBeijing JCZ Technology CO., LTD.Product:Laser Marking Software Model: Ezcad2.0 Features:Low cost, high quality; Intuitive, easy to learn and easy to use; Internationailzed interface will display any languages; Extended- axis motor control used for rotary axis, x- y tables, etc.; Control external equipment with built in I/0 objects import files, such as PLT, DXF, AI, DST, BMP, JPG, GIF, TGA, PNG, TIF, TIFF, etc; Add 1D and 2D barcodes like E…     

Optical Instruments and Components

Beijing Optical Instrument Plant Product:High- Precision Motorized Rotating Stage Model: MRS211 Specifications:Accuracy:2″,grating index dial ,liquid crystal display. Product:High- Precision Motorized Translation Stage Model: MTS317 Specifications:Stroke 400,linear slide block +ball guide screw(precision). Product:High- Accuracy Motorized Translation Stage Model: MTS603 Specifications:Stroke 150,linear slide block (high- accu- racy). Product:Precision Motorized Tilting Stage …     

WiMAX and Its Applications

As a new comer of thebroadband wirelessaccess technology,WiMAX is attracting moreand more attention.Afterthe introduction of WiMAXand IEEE 802.16standards,this paperanalyzes characteristicsof WiMAX technologiesand their systemarchitecture,and thendiscusses WiMAXapplication solutions.Itconcludes that WiMAXtechnologies are hopefulto replace Wi-Fitechnologies to becomethe final mobile solutionof “Last Mile BroadbandAccess”.     

MUSE and ABE Concept

1　IntroductionAccordingtoancientGreekmythologythereareninemuses ,eachofwhompresidedoveradifferentartorscience .Musehasbeencreditedasbeingthesourceofinspirationforartists ,writers ,poetsandmusicians.Inthispaper,theword“MUSE”isassociatedwithMobileUbiquitousServiceEnvironment ,avisionforfu tureworldofwireless ,whichalsosummonsinspira tionalinnovations .TheaimofMUSEistoenableuserstogetalwaysbestexperienceaccordingtotheirrequire mentsandpreferences ,wherevertheyareandwhenevertheyneed ,thro…     

Analogue v Digital：the pros and cons and some facts

There are a number of important issues that need to be discussed when potential CADAC users are contemplating the digital arena of mixers. We are facing some competition form this area and it is important that customers understand the advantages and disadvantages of digital belore making any purchasing decisions.     

New CCII and ICCII Based Realizations of L-C and L-R Mutators

New realizations of Chua L-C and L-R mutators using current conveyors (CCII) and inverting current conveyors (CCII) are introduced. Two realizations are available in the literature using CCII for each of the types of L-C and L-R mutators. For the type 1a L-R mutator three new realizations using CCII and ICCII are introduced to complete a family of four realizations. For the type 1b L-R mutator three new realizations using CCII and ICCII are introduced to complete a family of four realizations. For the type 2a L-C mutator fifteen new realizations using CCII and ICCII are introduced to complete a family of sixteen realizations. For the type 2b L-C mutator fifteen new realizations using CCII and ICCII are introduced to complete a family of sixteen realizations. For the type 2c L-C mutator eight new realizations using CCII and ICCII are introduced to complete a family of sixteen realizations. Finally for the types 2a and 2b L-R mutator fifteen new realizations using CCII and ICCII are given for each type to complete a family of sixteen realizations. Although this is a review paper and is partially tutorial it includes many new realizations of L-C and L-R mutators.     

Accurate and Simple Time Synchronization and Frequency Offset Correction in OFDM System

1　Introduction　OFDMisaneffectivetransmissionschemetocopewithmultipathfading[1] .Byinsertingaguardintervalbetweensymbolsblockscalledcyclicprefix ,theInterSymbolInterference (ISI)canbemitigated .OFDMwasadoptedasthemodulationschemeforaDigitalAu dioBroadcasting (DAB)system[2 ] andisalsoproposedastheterrestrialHDTVtransportinEurope[3] .　SymboltimingoffsetsinOFDMreceiversnotonlyin troduceISIbutalsocauselinearphaserotationsofthesignalconstellationofthereceiverFastFourierTrans form (F…