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分布式基站是一种在现代通信中用于完成网络覆盖、实现网络连接的现代化产品。通过基站分布式的设计能够构建起稳定的无线网络,为信息传输提供相应的物理支持。随着通信技术的快速发展,基站产品也越来越丰富,分布式基站成本较低、环境适应性较强,并且施工便利,应用也较为稳定,因此得到广泛的应用。本文首先介绍分布式基站的概念和特点,再阐述分布式基站的应用优势,最后针对分布式基站的5G无线网络设计做简要分析。 相似文献
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克拉霉素(Clarithromycin)是第二代十四元大环内酯抗生素, 其合成是保护技术应用和区域选择性研究的一次集中体现[1,2].目前, 美国雅培实验室和日本大正公司是以2′,4″-O-双(三甲基硅)红霉素A 9-O-(1-异丙氧环己基)肟(1)作为区域选择性前体制备的[1,3]; 而中国和印度制药企业多采用2′,4″-O-双(三甲基硅)红霉素A 9-O-(1-甲氧基-1-甲基乙基)肟(2)作为关键中间体[4,5].后者的主要杂质为6,11-O-双甲基红霉素A[6].对大环内酯的区域选择性进行了大量的研究后, 发现2′,4″-O-双(三甲基硅)红霉素A 9-O-(1-甲氧基环己基)肟(3)的区域选择性远低于空间结构差异不大的化合物1[7], 却与空间结构差异较大的化合物2一样, 易生成大量的6,11-O-双甲基化产物. 相似文献
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Zirconium(Zr) thin films deposited on Si(100) by pulsed laser deposition(PLD) at different pulse repetition rates are investigated. The deposited Zr films exhibit a polycrystalline structure, and the X-ray diffraction(XRD) patterns of the films show the α Zr phase. Due to the morphology variation of the target and the laser–plasma interaction, the deposition rate significantly decreases from 0.0431 /pulse at 2 Hz to 0.0189 /pulse at 20 Hz. The presence of droplets on the surface of the deposited film, which is one of the main disadvantages of the PLD, is observed at various pulse repetition rates. Statistical results show that the dimension and the density of the droplets increase with an increasing pulse repetition rate. We find that the source of droplets is the liquid layer formed under the target surface. The dense nanoparticles covered on the film surface are observed through atomic force microscopy(AFM). The root mean square(RMS) roughness caused by valleys and islands on the film surface initially increases and then decreases with the increasing pulse repetition rate.The results of our investigation will be useful to optimize the synthesis conditions of the Zr films. 相似文献
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We report a detailed ab initio study of the trapping behavior of interstitial helium atoms (IHAs) in hcp Ti. The tetrahedral interstitial site for one He is confirmed to be the most stable IHA configuration, but the most favorable interstitial site comprises two adjacent octahedral sites for two helium atoms. The octahedral IHA can trap another IHA regardless of the site where it is initially located, whereas the tetrahedral IHA cannot. Hybridization among the different states is responsible for the stable order, which has significant implications for He clustering and bubble nucleation that can affect material performance in future fusion reactors. These results provide the basis for the development of improved atomistic models. 相似文献
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采用碱性去活(BDS)C18柱分离测定了红霉素肟及相关化合物。以0.02 mol/L 磷酸氢二钾(用磷酸调pH 7.2)-乙腈-甲醇(体积比为50∶40∶10)为流动相,检测波长为210 nm,柱温为35 ℃。红霉素肟E、Z异构体及相关化合物红霉素A、红霉素A 8,9-脱水-6,9-半缩酮和红霉素A 6,9-9,12-螺缩酮五种组分分离完全,检测限(S/N=3)为6.0~24.0 ng,线性关系良好,方法准确可靠,用于实际样品分析时取得较好的效果。 相似文献
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采用反相高效液相色谱法对克拉霉素合成工艺中关键中间体E-2′,4″-双(三甲基硅)-红霉素A-9-(1-异丙氧环己基)肟、Z-2′,4″-双(三甲基硅)-红霉素A-9-(1-异丙氧环己基)肟和E-2′,4″-双(三甲基硅)-6-甲基红霉素A-9-(1-异丙氧环己基)肟、Z-2′,4″-双(三甲基硅)- 6-甲基红霉素A-9-(1-异丙氧环己基)肟及其相关的6种工艺杂质进行了分离、定性和定量分析。色谱柱为DIKMA公司的Inertsil ODS-3(150 mm×4.6 mm i.d., 5 μm);流动相 相似文献