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11.
A passive optical network (PON) scheme based on optical code division multiplexing (OCDM) for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM technology to guarantee the security, while the upstream traffics pass through the same optical fiber by the common time division multiple access (TDMA) technology to decrease the cost. This schemes are denoted as OCDM/TDMA-PON, which can be applied to an optical access network (OAN) with full services on demand, such as Internet protocol, video on demand, tele-presence and high quality audio. The proposed OCDM/TDMA-PON scheme combines advantages of PON, TDMA, and OCDM technology. Simulation results indicate that the designed scheme improves the OAN performance, and enhances flexibility and scalability of the system. 相似文献
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去年深圳高交会期间,暨南大学的站位被围得水泄不通,前来咨询的、索取资料的、交换名片的、购买展品的令人应接不暇,成为展区一道亮丽的风景线,连任仲夷、朱森林、王岐山、卢钟鹤等省市领导也兴致勃勃地前来观看。 是什么原因吸引了如此众多的热切目光? 相似文献
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陈Kun 《江西科技师范学院学报》2000,(4):111-113
超级市场的卖场设计已越来越被经营者所重视。传统的设计正逐步被淘汰。现在的设计开始更多地考虑顾客的需求。卖场的出入口、通道、卖点、商品陈列和卖场气氛等方面的设计正趋于人性化、煽动性。本文拟从这几个方面对超级市场的卖场设计进行探讨。 相似文献
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ZHANG Kai HAN Kun ZHANG Xuehai YANG Bai 《科学通报(英文版)》2005,50(14):1526-1528
In recent years, the semiconductor nanocrystals (NCs) have attracted great interest due to their potentials in photonics, electronics, magnetics and catalysis, and the monodispersed organic or inorganic microspheres doped NCs display predominant characteristics in the fabrication and study for photonic crystals, and considerable effor thas been devoted to the design and synthesis of CdTe NCs doped colloid with well fluorescencet. 相似文献
16.
LI Haiyan TANG Beisha* XIA Kun CAO Guifang SHEN Lu JIANG Hong PAN Qian SONG Yanmin CAI Fang 《自然科学进展(英文版)》2005,15(8)
Benignfamilialneonatalconvulsions(BFNC)is arareautosomaldominantinheritedepilepsysyn dromecharacterizedbyunprovokedpartialorgeneral izedseizures.Theseizuresusuallyoccurfromthesec onddayofbirthtothesixthmonthandremitsponta neouslyafterseveralweekstomonths.Mostindivid ualsareseizure freebytheageofsixmonths.The serumchemistryandneuroradiologicalexaminations,interictalelectroencephalogram(EEG),andpsy chomotordevelopmentareusuallynormal.However,10%to15%ofpatientshavetheriskofseizurere currencela… 相似文献
17.
Yan Kun Huang Zi-xiang Liu Si-min Liang Feng Wu Cheng-tai . College of Chemistry Molecular Sciences Wuhan University Wuhan Hubei China . Fujian Institute of Research on the Structure of Matter CAS Fuzhou Fujian China 《武汉大学学报:自然科学英文版》2004,(1)
0 IntroductionCucurbit [n]urils (Qn ,Fig .1.)arecyclicoligomersofnunitsofglycolurillinkedby 2nmethylenebridgesderivedfromformaldehyde.Theypossessacharacteristicannularshape,withtwoidenticalcarbonyl fringedportals[1 ,2 ] .Themostcom moncucurbituril,Q6 ,wasreportedtoaccommodatedifferentguestssuchaswater[3] ,THF[4 6] ,xenon[7] ,pyridium[8] andp xylyenediammonium[3] ionsandsoon .ThealkyldiaminesthreadthroughtheQ6 ,andformtherotaxanestructures[9 1 3] .Metalions[1 ,3 6 ,1 4 ,1 5] andclusters[8,… 相似文献
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Based on the first unde rwater railway shield tunnel, the Shiziyang shield tunnel of Guangzhou Zhu- jiang River, the prototype test was carried out against its segmental lining structure by using "multi-function shield tunnel structure test system". And the mechanical characteristics of segmental lining structure using straight assembling and staggered assembling were studied deeply. The results showed that, the mechanical characteristics of segmental lining structure varied with the water pressures; especially after cracking, the high water pressure played a significant role in slowing down the growing inner force and deformation. It also testi- fied that the failure characteristics varied with straight assembling structure and staggered assembling structure. Shear thilurc often occurred near longitudinal seam when using straight assembling. 相似文献
20.
YU Xianglin QU Hao HU Qihui HOU Kun YAN Yushi WU Dan ZHANG Pian LI Junbo 《武汉大学学报:自然科学英文版》2014,19(2):129-136
A rhodamine-benzimidazole conjugate(RB) as a probe was investigated.UV-Vis analysis showed that a strong absorption band at 552 nm was formed with the addition of Cu~(2+),while other transition metal ions induced a little more absorption.The absorption value of RB solution at 552 nm has a linear correlation with Cu~(2+) concentration between 35-70 μmol/L;the detection limit reached 6.82×10~(-2) μmol/L,which is lower than the settled limitation for copper in the drinking water(~30 μmol/L) standardized by World Health Organization(WHO).Moreover,FL analysis showed that only Fe~(3+) could induce large fluorescence intensity enhancement at 582 nm;other common metal ions including Cu~(2+) cannot induce the enhancement.There was a good linear correlation between relative fluorescence intensity and Fe~(3+) concentration ranging from 2 μmol/L to 20 μmol/L,and the detection limit reached1.70×10~(-2) μmol/L.The results showed that RB could detect Cu~(2+)and Fe~(3+) simultaneously,with the UV-Vis and fluorescence spectroscopy,respectively. 相似文献