Ka波段双平衡星型混频器的设计与仿真

采用0.15μm GaAs PHEMT工艺,设计了一个26-38 GHz单片双平衡星型混频器,本设计改变了星型混频器一贯的混合微波集成电路结构,设计了版图实现单片集成,最后得出电磁仿真结果。此混频器能在中频为DC-12 GHz时,电磁仿真结果达到7-10 dB的变频损耗和15 dB以上的端口隔离。     

花朵图像自动提取方法研究

采用改进的主动轮廓模型算法,实现从蝴蝶兰花簇图像中提取单个花朵图像,为自动识别蝴蝶兰的生长状态奠定基础。首先利用改进的骨架算法和轮廓重生算法,生成蝴蝶兰花簇的初始轮廓;然后利用含有形状能量的主动轮廓模型进行轮廓的演化,使其更接近真实的蝴蝶兰花簇边缘,最后根据蝴蝶兰花蕊位置获得相应的蝴蝶兰花朵。实例验证和比对实验结果表明,该模型能够较好的分割和提取蝴蝶兰花簇中单个花朵,并具有较强的抗噪能力。利用该方法,可以较好的提取蝴蝶兰花簇中的单个花朵,与人工提取效果进行比对,正确率达到了91.5%。     

生物芯片扫描仪研究进展

简要介绍生物芯片的基本概念以及生物芯片检测装置的国内外发展动态;分别介绍了本文设计的CCD系统生物芯片检测仪和激光共聚焦生物芯片扫描仪的原理、结构、工作状况以及设备的技术参数。最后指出更高分辨率(小于1μm)的生物芯片扫描仪是该设备今后的发展趋势。     

喷墨印刷沉积的PEDOT/PSS薄膜导电性能

利用压电喷墨印刷技术沉积了PEDOT/PSS有机导电薄膜,研究了退火温度和乙二醇掺杂对薄膜导电性能的影响。实验结果表明:未退火和退火温度为120,140,160℃时,薄膜表面平均粗糙度分别为8.15,4.10,3.36,2.66nm;乙二醇掺杂使导电激活能由未掺杂时的0.096eV减小为0.046eV;电导激活能减小表明PEDOT分子链从低电导率的卷曲构象向高电导率的伸展构象转变;此外,乙二醇掺杂促使PSS与PE-DOT/PSS分离,使团聚的PEDOT/PSS颗粒变小从而分散更均匀,降低了表面粗糙度。     

光无源器件在WDM网络中的应用

本文详细介绍光无源器件在ＷＤＭ网络中的主要作用及其基本现状,以ＷＤＭ网络为光导,对网络中应用的光无源器件作逐一介绍。     

用户移动性建模及其应用

在移动通信中，移动性建模技术可以广泛用于移动性管理、无线资源管理、移动切换、话务分析等不同方面。文中首先提出移动性建模的基本假设，并建立一般的移动性模型；在此基础上，详细介绍几类不同的移动性模型，并给出移动性建模的具体应用。     

广电网络业务发展的分析

以促进广电网络发展为纲,分析广电主要的3项增值业务:付费频道,高清互动,宽带业务。从实际出发,分析现状并为其正确定位,对其发展方向及业务增长方式题出建议,指出广电未来以电视业务宽带业务为主线的盈利格局。     

激光-感应复合熔覆Ni基WC复合层的工艺研究

为了提高熔覆效率与消除熔覆层的裂纹,采用激光-感应复合熔覆的方法在A3表面获得了无气孔与裂纹的Ni基WC复合层。研究了不同的加工参量对复合层质量的影响,结果表明,随着激光比能的增加,粉末面密度增加;在相同的激光比能条件下,随着粉末面密度增加,熔覆层的高度增加,稀释率减小;在相同的粉末面密度条件下,随着激光比能的增加,熔覆层的宽度略有增加。此外,相对于单纯的激光熔覆技术,激光-感应复合熔覆的效率约可以提高5倍。在激光-感应复合熔覆过程中,熔覆层与基材间的温度梯度大大降低,这是Ni基WC复合层无裂纹的关键原因。     

“Click handle”-modified 2′-deoxy-2′-fluoroarabino nucleic acid as a synthetic genetic polymer capable of post-polymerization functionalization

The functions of natural nucleic acids such as DNA and RNA have transcended genetic information carriers and now encompass affinity reagents, molecular catalysts, nanostructures, data storage, and many others. However, the vulnerability of natural nucleic acids to nuclease degradation and the lack of chemical functionality have imposed a significant constraint on their ever-expanding applications. Herein, we report the synthesis and polymerase recognition of a 5-(octa-1,7-diynyl)uracil 2′-deoxy-2′-fluoroarabinonucleic acid (FANA) triphosphate. The DNA-templated, polymerase-mediated primer extension using this “click handle”-modified FANA (cmFANA) triphosphate and other FANA nucleotide triphosphates consisting of canonical nucleobases efficiently generated full-length products. The resulting cmFANA polymers exhibited excellent nuclease resistance and the ability to undergo efficient click conjugation with azide-functionalized molecules, thereby becoming a promising platform for serving as a programmable and evolvable synthetic genetic polymer capable of post-polymerization functionalization.

Polymerase-mediated incorporation of a “click handle”-modified fluoroarabinonucleic acid (cmFANA) triphosphate produces a new class of nuclease-resistant, evolvable genetic polymers that can be functionalized with azide-containing molecules.     

Synthesis and Anti-Neuroinflammatory Activity of 1,7-diphenyl-1,4-heptadien-3-ones in LPS-Stimulated BV2 Microglia Via Inhibiting NF-κB/MAPK Signaling Pathways

A series of 1,7-diphenyl-1,4-heptadien-3-ones with various substituents (HO-, CH₃O-, CH₃-, Cl-) on the phenyl rings were synthesized and evaluated for anti-neuroinflammatory effects in LPS-stimulated BV2 microglia. The pharmacological results showed that the target compounds bearing methoxy groups greatly inhibited LPS-induced NO release, and that the active compounds CU-19 and CU-21 reduced the level of NO, TNF-α, IL-6 and PGE-2, downregulated the expression of COX-2 and iNOS in LPS-stimulated BV2 cells. A study of the mechanism of action revealed that CU-19 and CU-21 inhibited the nuclear translocation of NF-κB and phosphorylation of MAPKs (ERK, JNK, and p38). A preliminary pharmacokinetic study in rats revealed that the pharmacokinetic properties of CU-19 and CU-21 were dramatically ameliorated in comparison with the pharmacokinetic properties of curcumin.