Miniaturized microstrip branch-line coupler with good harmonic suppression performance

This paper presents a miniaturized microstrip branch-line coupler with good harmonic suppression performance. The proposed coupler consists of four branch-line sections, each of which is loaded by open-circuit stubs both at the center and the two ends. This type of loading can realize size reduction and harmonic suppression. As an example, a proposed branch-line coupler operating at 1.0 GHz is designed, fabricated and measured. The results show that the proposed branch-line coupler occupies 67% size of a conventional one and has better than 20 dB suppression from 1.9 to 5.8 GHz. Furthermore, the high slop of the transition band ensures good selectivity of the coupler.     

轮扣式钢管支模架节点连接性能试验研究

设计轮扣式钢管支模架节点半刚性水平力加载试验。选用3组试件,通过对试验现象和所得数据的分析及与扣件式钢管脚手架节点刚度的对比分析,得到结论:轮扣式钢管脚手架节点具有典型的半刚性连接特性,轮扣式钢管脚手架节点的半刚性受不同搭设间距的影响较小;当节点弯矩在控制弯矩的20%以下时,节点的初始连接刚度变化波动略大;当超过20%时,节点连接刚度曲线趋于稳定一致;得到的3组试件节点的连接刚度相当于扣件式钢管脚手架在扣件拧紧力矩40 N.m时的连接刚度。轮扣式钢管脚手架连接稳定性好,搭设质量优于传统的扣件式钢管脚手架。     

小份量,大用途——纳米纤维在非织造产业中的应用

在第十四届非织造展览会上,Elmarco公司展示了其专利Nanospider(纳米纺丝)技术与非织造材料复合的生产工艺和设计。通过分析Nanospider技术与传统静电纺的区别,分析介绍了纳米/非织造复合材料的生产工艺及产品性能,并探讨了Nanospider技术与非织造生产工艺结合的现状和发展前景。     

Effects of thermal processing and iron doping in co-sputtered barium strontium titanate thin films

The effects of the thermal processing and iron doping on RF magnetron co-sputtered barium strontium titanate thin film properties have been investigated. X-ray diffraction and Raman spectroscopy have been used to determine the structural evolution of the films as a function of the annealing temperature and the amount of iron dopant. X-ray photoelectron spectroscopy and electron paramagnetic resonance spectroscopy were employed to gain information about the chemical binding states and the defect structure. The enhancement of the quality factor Q, as well as the decreasing permittivity and tunability due to iron acceptor doping are demonstrated.     

Synthesis and properties of bromide‐ functionalized poly(isobutylene‐co‐p‐ methylstyrene) random copolymer

Poly(isobutylene‐co‐p‐methylstyrene) (IB/p‐MS) random copolymer is a new generation of polyisobutylene‐based elastomers. The cationic copolymerization of IB with p‐MS was thoroughly examined by using 2‐chloro‐2,4,4‐trimethylpentane/ethylaluminiumsesquichloride/electron donor as initiating system. IB/p‐MS random copolymers with high molecular weight were obtained at elevated temperature through the addition of ethyl acetate; the reaction proceeded in a mildly exothermic manner. Although the reactivity ratios of comonomer pairs differ by close to an order of magnitude, p‐MS was uniformly distributed in the chains. IB/p‐MS random copolymer can be brominated by adding molecular bromine into the copolymer solution, thereby yielding a completely saturated polymer backbone with a chemically reactive site. The types and selection of appropriate vulcanization systems for bromide‐functionalized IB/p‐MS random copolymers are also discussed. © 2016 Society of Chemical Industry     

高层建筑物室内装饰施工技术探讨

本文从时代发展的角度，对高层建筑的室内装饰施工技术及其要求进行分析。