A Novel Kind of Wideband Low-Profile Dielectric Resonator Antenna Suitable for Beam-scanning Applications

In this paper, a low-profile wideband dielectric resonator antenna(DRA) with a very compact planar size is investigated. The antenna consists of a high permittivity dielectric sheet on the top, a low permittivity substrate in the middle, and a probe feeding structure at the bottom. By digging an annular slot in the designated area of the square dielectric sheet, the resonant frequency of fundamental TE111 mode can be effectively increased to be close to the high-order TE131 mode. The two modes can be finally merged together, yielding a wide impedance bandwidth of16.6%. Most importantly, the combination of the two modes is done on the premise of a fixed antenna planar size, which can be very compact and suitable for beam-scanning applications. A probe feeding structure is used to excite the DRA, making the antenna simple and practical to be integrated with other RF circuits. For verification, antenna prototypes with singlefeed linear polarization and differential-feed dual polarization were fabricated and measured. Reasonable agreement between the measured and simulated results is observed.

2008-2017年湖北省荆州市手足口病时空特征分析

目的分析2008-2017年湖北省荆州市手足口病时空分布特征,为手足口病防控工作提供依据。方法在街道/乡镇尺度采用ArcGIS 10软件对手足口病发病数据空间聚集性进行全局和局部自相关分析,采用SaTScan 9.4软件对手足口病发病数据时空聚集性进行分析。结果荆州市累计报告发病53 159例,年平均发病率为91.59/10万。空间自相关分析显示,发病率存在空间正相关,主聚集区域位于荆州市中心城区及周边县(市)与其接壤的乡镇,发病率存在明显时空聚集性特征。结论在街道/乡镇尺度上掌握荆州市手足口病发病数据的空间分布、时空聚集等分布特征,对于合理配置公共卫生资源、有效预防和控制手足口病有重要公共卫生学意义。

Multi boron-doping effects in hard carbon toward enhanced sodium ion storage

Hard carbon (HC) has been considered as promising anode material for sodium-ion batteries (SIBs).The optimization of hard carbon’s microstructure and solid electrolyte interface (SEI) property are demonstrated effective in enhancing the Na+storage capability,however,a one-step regulation strategy to achieve simultaneous multi-scale structures optimization is highly desirable.Herein,we have systematically investigated the effects of boron doping on hard carbon’s microstructure and interface chemistry.A variety of structure characterizations show that appropriate amount of boron doping can increase the size of closed pores via rearrangement of carbon layers with improved graphitization degree,which provides more Na+storage sites.In-situ Fourier transform infrared spectroscopy/electrochemical impedance spectroscopy (FTIR/EIS) and X-ray photoelectron spectroscopy (XPS) analysis demonstrate the presence of more BC3and less B–C–O structures that result in enhanced ion diffusion kinetics and the formation of inorganic rich and robust SEI,which leads to facilitated charge transfer and excellent rate performance.As a result,the hard carbon anode with optimized boron doping content exhibits enhanced rate and cycling performance.In general,this work unravels the critical role of boron doping in optimizing the pore structure,interface chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced Na+storage performance.

Cyclometalated Ruthenium Complexes of 1,2,3-Triazole-containing Ligands： Synthesis, Structural Studies, and Electronic Properties

Six bis-tridentate and two tris-bidentate cyclometalated ruthenium complexes with a 1,2,3-triazole-containing ligand have been prepared and characterized. Single-crystal X-ray analyses of complexes [（MeOptpy）Ru（Budtab）]-（PF6） and [（Mebip）Ru（Budtab）]（PF6） are presented, where MeOptpy is 4′-p-methoxyphenyl-2,2′：6′,2＂-terpyridine, Budtab is the 2-deprotonated form of 1,3-di（N-n-butyl-l,2,3-triazol-4-yl）benzene, and Mebip is bis（N-methyl-ben-zimidazolyl）pyridine. The electronic properties of these complexes are probed by spectroscopic and electrochemical analyses. Time-dependent density functional theory calculations have been performed to assist the assignment of the absorption spectra.

Compact input-reflectionless balanced bandpass filter with flexible bandwidth using three-line coupled structure

A compact input-reflectionless balanced bandpass filter(BPF)with flexible bandwidth(BW)using a three-line coupled structure(TLCS)is presented in this paper.For the differential mode(DM),the TLCS is applied to achieve the bandpass response;meanwhile,the input coupled-feed line of the TLCS is reused in the input absorption network.This design shows a good fusion of the absorptive and BPF sections,effectively reducing the circuit size,and the BWs of the two sections that can be controlled separately result in a flexibly controllable DM response BW of the proposed input-reflectionless balanced BPF.Detailed analyses of the ratio of the two-part BWs have been given for the first time,which is vital for the passband flatness and reflectionless feature.In the codesign of this work,the input-reflectionless DM bandpass response can be optimized easily,while wideband common mode(CM)noise absorption is achieved by the input absorption network.To verify the design method,a prototype with a compact layout(0.52λ×0.36λ)is designed and measured in the 0-7.0 GHz range.The DM center frequency(f0)is 2.45 GHz with a measured 3 dB fractional bandwidth of 31.4%.The simulation and measurement results with good agreement are presented,showing good performance,e.g.,low insertion loss(0.43 dB),wide upper stopband for the DM bandpass response(over 20 dB rejection level up to 2.72f0),and wideband DM reflectionless and CM noise absorption(fractional absorption bandwidth of 285.7%).