高兼容性分形阵列仿生天线设计

本文针对移动通信系统、射频识别系统、超宽带系统、移动数字电视系统对天线的性能要求,创造性的将蝶形仿生天线与希尔伯特分形阵列相结合,设计了一款高兼容性分形阵列仿生天线,制作了天线样品并测试了天线的辐射特性。测试结果表明,该款天线完全覆盖了第二代至第五代移动通信所有工作频段、射频识别系统频段、超宽带系统频段和移动数字电视系统频段。使用该天线的智能终端将兼具手机通信、射频卡读写、超宽带传输和移动数字电视等多种功能,该天线有较大的应用潜力。

用于移动数字电视的多层渐变分形缝隙石墨烯天线

本文针对移动数字电视系统对天线的性能要求,创造性地将多层天线结构、分形缝隙天线、石墨烯导电墨水相结合,设计了一款用于移动数字电视的多层渐变分形缝隙石墨烯天线,制作了天线样品并测试了天线辐射特性。该款天线的中心频率为12.000 GHz,工作频带为10.026~14.938 GHz,绝对带宽为4.912GHz,相对带宽为39.35%,回波损耗最小值为?39.14 dB。该款天线完全覆盖了移动数字电视系统工作频段,是一款小尺寸、宽频带、集成化的移动数字电视天线,能够满足移动数字电视系统信号稳定、覆盖广泛、接收迅速、画面清晰、移动性强等要求。

Retro-labyrinthine Lesion Site Detected by Galvanic Vestibular Stimulation Elicited Vestibular-evoked Myogenic Potentials in Patients with Auditory Neuropathy

Objective Auditory neuropathy(AN)is a unique pattern of hearing loss with preservation of hair cell function.The condition is characterized by the presence of otoacoustic emissions(OAE)or cochlear microphonic(CM)responses with severe abnormalities of the auditory brainstem response(ABR).The vestibular branches of the VIII cranial nerve and the structures innervated by it can also be affected.However,the precise lesion sites in the vestibular system are not well characterized in patients with AN.Methods The air-conducted sound(ACS)vestibular-evoked myogenic potentials(VEMPs)and galvanic vestibular stimuli(GVS)-VEMPs were examined in 14 patients with AN.Results On examination of VEMPs(n=14,28 ears),the absent rates of ACS-cervical VEMP(cVEMP),ACS-ocular VEMP(oVEMP),GVS-cVEMP,GVS-oVEMP and caloric test were 92.9%(26/28),85.7%(24/28),67.9%(19/28),53.6%(15/28),and 61.5%(8/13),respectively.Impaired functions of the saccule,inferior vestibular nerve,utricle,superior vestibular nerve,and horizontal semicircular canal were found in 25.0%(7/28),67.9%(19/28),32.1%(9/28),53.6%(15/28)and 61.5%(8/13)patients,respectively.On comparing the elicited VEMPs parameters of AN patients with those of normal controls,both ACS-VEMPs and GVS-VEMPs showed abnormal results in AN patients(such as,lower presence rates,elevated thresholds,prolonged latencies,and decreased amplitudes).Conclusion The study suggested that patients with AN often have concomitant vestibular disorders.Retro-labyrinthine lesions were more frequently observed in this study.GVS-VEMPs combined with ACS-VEMPs may help identify the lesion sites and facilitate detection of areas of vestibular dysfunction in these patients.

Axial uniformity diagnosis of coaxial surface wave linear plasma by optical emission spectroscopy

The coaxial surface wave linear plasma with preeminent axial uniformity is developed with the 2.45 GHz microwave generator.By optical emission spectroscopy,parameters of the argon linear plasma with a length over 600 mm are diagnosed under gas pressure of 30 and 50 Pa and different microwave powers.The spectral lines of argon and Hβ(486.1 nm)atoms in excited state are observed for estimating electron excitation temperature and electron density.Spectrum bands in305–310 nm of diatomic OH(Σ-Π+A X22 i)radicals are used to determine the molecule rotational temperature.Finally,the axial uniformity of electron density and electron excitation temperature are analyzed emphatically under various conditions.The results prove the distinct optimization of compensation from dual powers input,which can narrow the uniform coefficient of electron density and electron excitation temperature by around 40%and 22%respectively.With the microwave power increasing,the axial uniformity of both electron density and electron excitation temperature performs better.Nevertheless,the fluctuation of electron density along the axial direction appeared with higher gas pressure.The axial uniformity of coaxial surface wave linear plasma could be controlled by pressure and power for a better utilization in material processing.

绿色技术创新对企业价值的影响效应研究——基于ESG评级中介作用的视角

基于2017~2021年中国A股上市制造业企业数据,实证分析绿色技术创新对企业价值的影响,以及在这一影响过程中ESG评级的中介作用,并进一步检验了企业价值水平、政策环境、产权性质对绿色技术创新与企业价值关系的影响效应。研究结果表明:绿色技术创新对企业价值和企业ESG评级具有正向促进作用,且ESG评级在其中发挥中介传导作用;同时,企业价值水平越高,绿色技术创新对企业价值的促进作用越明显;低碳城市试点政策能够增强绿色技术创新对企业价值的影响效应;对于非国有企业,绿色技术创新对企业价值的提升作用更大。

Changes in soil faunal density and microbial community under altered litter input in forests and grasslands

Root and foliar litter inputs are the primary sources of carbon and nutrients for soil fauna and microorganisms,yet we still lack a quantitative assessment to evaluate the effects of root and foliar litter on various groups of soil organisms across terrestrial ecosystems.Here,we compiled 978 paired observations from 68 experimental sites to assess the directions and magnitudes of adding and removing foliar and root litter on the soil faunal density and microbial biomass that was evaluated by phospholipid fatty acids(PLFAs)across forests and grasslands worldwide.We found that litter addition had only a marginal effect on soil faunal density but significantly increased the soil total microbial-,fungal-and bacterial-PLFAs by 13%,14%,and 10%,respectively,across ecosystems,suggesting that the soil microbial community is more sensitive to carbon source addition than soil fauna,particularly in soils with low carbon to nitrogen ratios.In contrast,removing litter significantly decreased the soil faunal density by 17%but had few effects on soil microorganisms.Compared with foliar litter,root litter input had a more positive effect on the development of soil fungal taxa.The effect of both litter addition and removal on soil faunal density and microbial biomass did not differ between humid and arid regions,but a greater influence was observed in grasslands than in forests for soil microbial community.Our results highlight that the increasing litter production under a global greening scenario would stimulate microbial activity in grasslands more than in forests,and this stimulation would be greater for soil microbes than soil fauna.

Inducing the SnO2-based electron transport layer into NiFe LDH/NF as efficient catalyst for OER and methanol oxidation reaction

In an electrocatalyst with a heterointerface structure,the different interfaces can efficiently adjust the catalyst’s conductivity and electron arrangement,thereby enhancing the activity of the electrocatalyst.Ultrathin and smaller Ni Fe LDH was successfully constructed on the surface of SnOnanosheet supported NF by layer by layer assembly,and exhibits lower overpotential of 234 mV at a current density of 10 m A cm,which only increases by 6.4%even at a high current density of 100 mA cm.The excellent OER activity of catalyst is attributed to the contribution of the semiconductor SnOelectron transport layer.Through experiments and characterization,3d structure SnOnanosheets control the growth of ultra-thin nickel-iron,the hierarchical interface between SnOand Ni Fe LDH can change the electron arrangement around the iron and nickel active centers at the interface,resulting the valence states of iron slightly increased and Nicontent increased.The result will promote the oxidation of water.Meanwhile,the SnOsemiconductor as electron transport layer is conducive to trapping electrons generated in oxidation reaction,promoting electrons transferring from the Ni Fe LDH active center to the Ni substrate more quickly,and enhance the activity of Ni Fe LDH.It also shows excellent activity in an electrolyte solution containing 0.5 M methanol and 1 M KOH,and only 1.396 V(vs.RHE)is required to drive a current density of 10 mA cm.

Analytical model for the transient permittivity of uncured TiO_(2) whisker/liquid silicone rubber composites under an AC electric field

The electric field grading of dielectric permittivity gradient devices is an effective way of enhancing their insulation properties.The in situ electric field‐driven as-sembly is an advanced method for the fabrication of insulation devices with adaptive permittivity gradients;however,there is no theoretical guidance for design.In this study,an analytical model with a time constant is developed to determine the transient permittivity of uncured composites under an applied AC electric field.This model is based on optical image and dielectric permittivity monitoring,which avoids the direct processing of complex electrodynamics.For a composite with given components,the increased filler content and electric field strength can accelerate the transient process.Compared with the finite element method based on differential equations,this statistical model is simple but efficient,and can be applied to any low‐viscosity uncured composites,which may contain multiple fillers.More importantly,when a voltage is applied to an uncured composite insulating device,the proposed model can be used to analyse the spatiotemporal permittivity characteristics of this device and optimise its permittivity gradient for electric field grading.

Warming and altered precipitation rarely alter N addition effects on soil greenhouse gas fluxes:a meta-analysis

Background Changes in soil greenhouse gas(GHG)fluxes caused by nitrogen(N)addition are considered as the key factors contributing to global climate change(global warming and altered precipitation regimes),which in turn alters the feedback between N addition and soil GHG fluxes.However,the effects of N addition on soil GHG emissions under climate change are highly variable and context-dependent,so that further syntheses are required.Here,a meta-analysis of the interactive effects of N addition and climate change(warming and altered precipitation)on the fluxes of three main soil GHGs[carbon dioxide(CO_(2)),methane(CH_(4)),and nitrous oxide(N_(2)O)]was conducted by synthesizing 2103 observations retrieved from 57 peer-reviewed articles on multiple terrestrial ecosystems globally.Results The interactive effects of N addition and climate change on GHG fluxes were generally additive.The combination of N addition and warming or altered precipitation increased N_(2)O emissions significantly while it had minimal effects on CO_(2)emissions and CH_(4)uptake,and the effects on CH_(4)emissions could not be evaluated.Moreover,the magnitude of the combined effects did not differ significantly from the effects of N addition alone.Apparently,the combined effects on CO_(2)and CH_(4)varied among ecosystem types due to differences in soil moisture,which was in contrast to the soil N_(2)O emission responses.The soil GHG flux responses to combined N addition and climate change also varied among different climatic conditions and experimental methods.Conclusion Overall,our findings indicate that the effects of N addition and climate change on soil GHG fluxes were relatively independent,i.e.combined effects of N addition and climate change were equal to or not significantly different from the sum of their respective individual effects.The effects of N addition on soil GHG fluxes influence the feedbacks between climate change and soil GHG fluxes.