毫米波分支线定向耦合器的设计与优化

本文先介绍了分支线正交定向耦合器的概念与工作原理;然后根据该原理在ADS2009软件下设计仿真了工作在Ka波段的微带线定向耦合器,并对Ka波段的耦合器模型进行了改良,使之实际面积缩小的同时能达到原有的性能。     

The activation of fluorgypsum with slag activator and the fluorine solidification mechanics

The mechanism of activator to fluorgypsum and the fluorine solidification were investigated by the performances of composite binding material. Through the setting time testing of fluorgypsum with NaOH, Na₂SO₄ and NaF, the least activator dosage were all 1%. And the cementitious material over 80% of fluorgypsum was processed to improve its quality with slag, fly ash and clinker. The maximum compressive strength of composite binding material was over 12.90 MPa in 28 days, and the concentration of fluroride reduced 64.7% which compared with the pure fluorgypsum binding material. Analysis of X-ray diffraction and scanning electron microscopy images showed that ettringite crystals, dihydrate gypsum crystals and C-S-H gel were filled with each other. The unreacted CaF₂ crystals were embedded by a great deal of network and filamentous C-S-H gel. It was the main reason that the composite binding material strength improved, water resistance increased and leaching toxicity reduced.     

Ku波段宽带平行耦合微带线带通滤波器的设计

阐述了平行耦合微带线滤波器的原理,利用Matlab编程计算,结合ADS2009的原理图与Momentum进行联合优化仿真,同时给出了中心频率在16.1 GHz、宽带为1.6 GHz的滤波器设计实例与步骤。仿真结果显示,该设计满足工程需求,并计划投入生产。     

在建高层建筑火灾及处置

通过对近年来在建高层建筑火灾案例的总结与分析,归纳出在建高层建筑的火灾特点,提出了在建高层建筑火灾预防措施和扑救对策。     

碱改性米糠炭对水中四环素的吸附性能研究

为探索高效利用生物质资源制备生物炭去除水体中的抗生素,以米糠为原料,采用600℃限氧热裂解法制备成米糠炭,并通过NaOH浸渍改性制备成碱改性米糠炭(NRB),探讨其吸附四环素的效果和机理。结果表明,NRB相对改性前有部分孔隙结构发生坍塌,拥有更大的比表面积和总孔隙容积。NRB吸附四环素的优化条件为:生物炭剂量为2 g/L,初始四环素质量浓度20 mg/L,溶液pH在7～11,环境温度25℃,吸附时间12 h。在40℃,Langmuir模型中NRB的理论最大吸附容量达到了159.8 mg/g,相比米糠炭提高了2.54倍。NRB吸附过程的动力学特征更符合准2级动力学模型,整个吸附过程主要受控于化学吸附,且比改性前对温度表现出更好的适应性。     

固相微萃取在分析化学中的应用

综述了９０４上代以来在分析化学领域兴起的一门样品前处理新技术－－固相微萃取。对基本理论、实验装置及使用条件、以及在分析化学中的应用作了较全面的介绍。