共查询到20条相似文献,搜索用时 31 毫秒
1.
ZHANGYun-chuan WANGBing-zhong 《中国电子科技》2005,3(1):40-44
Advances in developing transitions in microwave integrated circuits during the last ten years are reviewed. Some typical structures of transition are introduced, Transition structures can be classified into two basic types: one is transition between the same ]rind of transmission lines on different planes of a common substrate, the other transition between different types of transmission lines.Furthermore, future development of transition structures is discussed. 相似文献
2.
A band type inhomogeneity with 1.2-2.0 mm width in GaAs single crystal grown in space was revealed by using electrical plate technique. The striations have not been found in this area by anodic etching. 相似文献
3.
4.
5.
In this paper,the dependencies of Young's modulus and attenuation decrement on samarium sulfide polycrystals(SmS)under various annealing temperatures are studied by the piezoelectric ultrasonic composite oscillator technique at a frequency of 100 kHz in the temperature range of 80-300 K.A decrease in Young's modulus with an increase of the annealing temperature due to the texturing of the material was revealed.At the same time,attenuation peaks were observed at temperatures about 90 and 125 K,presumably due to Niblett-Wilks and Bordoni relaxations. 相似文献
6.
7.
Pankaj Kumar 《中兴通讯技术(英文版)》2004,(2)
India is emerging as one of the most competitive telecom markets.Thispaper first introduces key wireless operators in India,and then focuses onthe subscriber growth,ARPU,value-add services and service quality of thismarket.It concludes that both equipment vendors and foreign operators haveshown great interest in the market. 相似文献
8.
Jean-Pierre Timmermans Dirk Adriaensen 《电子显微学报》2001,20(1):1-10
1.IntroductionOverthelastfourdecades,fluorescencemicroscopyhasexperiencedatremendousinnovat-ingevolutionandisnowadaysawellestablishedtechniqueinmanyareasofbiomedicalre-search.Inaddition,fluorescencemicroscopicalimaginghasprovenanessentialtoolforstudy-ingbothcellstructureanddynamicprocessestakingplacewithinonecellorbetweenneigh-bouringcells.Thepresentshortreviewwillfocusonthemostrecentdevelopmentsinthisfieldofmicroscopy.2.ConventionalfluorescencemicroscopyTheterm“fluorescence”denotestheprope… 相似文献
9.
Terry von Bibra 《e & i Elektrotechnik und Informationstechnik》2002,119(12):a4-a5
AktuellAktuelle Studie
Mobilfunktrends in ?sterreich 相似文献10.
《液晶与显示》1994,(4)
The frequency shift in the-optieal-field-induced Freedericksz matisition in a nematic Iiquid crystal film is in-
vestigated theoretically and experirnentally. We obtain the temporal evolution of the frequency shift, and find
that the maximum frequency shift is proportional to the square of the light beam intensity. The experimental results are in agreement with the theoretical prediction. 相似文献
11.
12.
1 Introduction To realize high intensification of communi-cation networks means that the minimum input and the most rational resource allocation not only provide high quality services but also obtain the best economic benefit and the biggest development s… 相似文献
13.
Altukhov I. V. Kagan M. S. Paprotskii S. K. Khvalkovskii N. A. Rodionov N. B. Bolshakov A. P. Ralchenko V. G. Khmelnitskii R. A. 《Journal of Communications Technology and Electronics》2020,65(11):1336-1338
Journal of Communications Technology and Electronics - The conductivity of epitaxial diamond films lightly doped with boron has been studied at strong electric fields up to ~5 × 105 V/ cm. It... 相似文献
14.
15.
Opticalsolitonsinfibersarepulsesthatpropagatepreservingtheirshapeorintensityundercertainconditions,becausetheeffectsofintensity--dependentrefractiveindexofthefiberexactlycompensateforthepulse--spreadingeffectsofgroup--velocitydispersion(GVD)[lj.Intheanomalous--dispersionregimeofthefiber,brightsolitonscanbeobtainedandhavebeenstudiedextensively.Inthenormal--dispersionregion,darksolitonscanbeobtained.Theexistenceofdark--pulsesolitonshasbeenverifiedinexperiments.Thepropertiesofdarksolitonshavebe… 相似文献
16.
ZHANG Shi-bing~ 《中国邮电高校学报(英文版)》2005,12(4)
1IntroductionUltra-WideBand (UWB) communicationis a promis-ingtechnique for short rang,high speed wireless appli-cations due to its high robustness to multipath fading,high rate , low in cost and small power consump-tion[1 ~3]. This novel technique has the advantages ofproviding single ,integrated,homogeneous and seamlessaccess for a wide variety of wireless services ,and ini m-itable and potential wide applications in the fields ofpublic service , military affairs , medical treatment andcon… 相似文献
17.
HigherOrderModesinRTHOCTLiuYuanan;TangBihuaANDGaoYougang(DepartmentofTelecommunicationsEngineering,BeijingUniversityofPostsan... 相似文献
18.
LI Liang-chuan ZHANG Yan-gan LI Ling XU Da-xiong Optical Communications Center Beijing University of Posts Telecommunications Beijing P.R. China. 《中国邮电高校学报(英文版)》2004,11(2)
1 Introduction ThePONtechnologythatispacket orientediswidelyacceptedasanopticalaccesssolution ,butitstillneedstobetechnicallysuperiorforthefuturerequirement[1 ] .Wewillintroducethenewlyap provedGPONstandardsthatcarryatwo foldpromiseofbothhigherbit ratesandhigherefficien cywhenaccessingmultipleservicesoverthePONtopology . BurstmodetransmissionisinherenttoPONbe causeofTimeDivisionMultipleAccess (TDMA) .Upstreamtrafficismorecomplicatedthandown streamtrafficowingtothesharedmedianatureo… 相似文献
19.
20.
《中兴通讯技术(英文版)》2007,(2):34-37
The convergence of telecom networks requires an improved Quality of Service (QoS) solution. The introduction of the QoS resource control architecture based on the IP Multimedia Subsystem (IMS) framework is a way to solve QoS problems in the converged networks. Services,QoS guarantee,resource control and accounting functions are integrated into this IMS-based QoS control architecture. It is a solution to the problems currently facing the fixed network operators,helping them offer more QoS-guaranteed multimedia services such as 3D games,and make a transition from bandwidth providers to genuine telecom services providers. 相似文献