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《实验室研究与探索》2017,(10)
飞秒孤子作为未来大容量、大数据光纤通信的载流已经成为了当前重要研究方向,建立了标准单模光纤存在噪声时的波解体和孤子形成模型。分析结果表明:对于长于200 ps的脉冲,即使是低噪声功率,波解体调制不稳定性机制会导致噪声放大;当脉冲短于20 ps,波解体实现大量孤子是由于脉冲崩溃和脉冲谱展宽,而在它们之间的脉冲时波解体实现大量孤子主要是由于脉冲崩溃。脉冲调制的结果对于克服光纤损耗及非线性有一定的理论和实际意义。 相似文献
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通过理论分析和仿真试验,研究了锥形光纤的几何形状对锥形光纤的传输损耗和耦合效率的影响。用几何光学的分析方法,说明了光信号在锥形光纤中的传输损耗远低于同类型的圆柱形光纤;仿真试验研究了光源与光纤的相对位置、锥形光纤的尖端半径、锥形光纤的锥角大小对锥形光纤耦合效率的影响。 相似文献
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通过利用用传输矩阵法从理论上计算分析了相移光纤光栅的反射谱特性,着重讨论了相移大小、单点和多点相移对光纤光栅反射谱的影响以及切趾函数对光纤光栅反射谱的影响。最后简述了相移光纤光栅的应用。 相似文献
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早在十九世纪六十年代初,B．C．Brodie在研究石墨的性质时发现,把天然石墨与硫酸或硝酸作用,在受热时石墨的体积会发生一定的膨胀。Berthelor在研究石墨的非均相反应时,也发现类似现象。这种利用物理或化学方法使非碳质反应物插入石墨层间,和碳素的六角网络平面结合的同时又保持了石墨形状结构的晶体化合物就是石墨层间化合物（Graphite Intercalation Compounds,简称GIC）。 相似文献
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贵金属纳米粒子因其特有的光学以及化学和催化性能,正引起科技界越来越浓厚的兴趣.通常这些特性决定于这些金属粒子的粒径和形态.由于非球形粒子比各向同性的球形粒子具有更优越的性能,它们已经成为研究的焦点,人们正在努力寻找粒子形状如何影响粒子理化性能的答案.贵金属纳米粒子的形状可控合成技术已经取得了明显进展.本文就贵金属纳米粒子的形状可控合成及其应用研究的当前进展进行综合评述. 相似文献
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利用virial理论和数值模拟对色散管理光通信系统中的孤子传输进行了研究.结果表明,在普通光纤与色散补偿光纤的交界处,孤子幅度不连续,其幅度有所降低,但其形状保持不变.在小损耗光纤中传输的孤子,通过放大器幅度得到放大的同时,形状将自动得到恢复,可以稳定地、长距离不变形地传输,具有理想信息载体的特性. 相似文献
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全光纤的Mach-Zehnder干涉仪是一种重要的干涉器件,因其具有干涉现象、体积小、重量轻、结构紧凑、灵敏度高等特点,可用于光纤通讯和光纤传感领域。本文利用干涉分析方法,通过计算机数值模拟,研究了Mach-Zehnder干涉仪的传输特性．得出了输出端的谱线与两个耦合器的分光比变化的关系。 相似文献
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本文报道了对Ce：KNSBN晶体光折变性能的研究。主要研究了两波耦合有效增益强度特性和四波混频相位共轭反射率的强度特性。同时测量了该晶体对e光的透过率。 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献