Characteristics of the quasi-16-day wave in the mesosphere and lower thermosphere region as revealed by meteor radar,Aura satellite,and MERRA2 reanalysis data from 2008 to 2017

This study presents an analysis of the quasi-16-day wave(Q16DW)at three stations in the middle latitudes by using a meteor radar chain in conjunction with Aura Microwave Limb Sounder temperature data and MERRA2(Modern-Era Retrospective Analysis for Research and Applications,Version 2)reanalysis data from 2008 to 2017.The radar chain consists of three meteor radar stations located at Mohe(MH,53.5°N,122.3°E),Beijing(BJ,40.3°N,116.2°E),and Wuhan(WH,30.5°N,114.6°E).The Q16DW wave exhibits similar seasonal variation in the neutral wind and temperature,and the Q16DW amplitude is generally strong during winter and weak around summer.The Q16DW at BJ was found to have secondary enhancement around September in the zonal wind,which is rarely reported at similar latitudes.The latitudinal variations of the Q16DW in the neutral wind and temperature are quite different.The Q16DW at BJ is the most prominent in both neutral wind components among the three stations and the Q16DW amplitudes at MH and WH are comparable,whereas the wave amplitude in temperature decreases with decreasing latitude.The quasi-geostrophic refractive index squared at the three stations in the period from 2008 to 2017 was revealed.The results indicate that the Q16DW in the mesosphere and lower thermosphere(MLT)at MH has a limited contribution from the lower atmosphere.Around March and October,the Q16DW in the troposphere at BJ can propagate upward into the MLT region,whereas at WH,the contribution to the Q16DW in the MLT region is largely from the mesosphere.

Role of Ni species in ZnO supported on Silicalite-1 for efficient propane dehydrogenation

Propane dehydrogenation(PDH)is one of the most effective technologies to produce propene.Non-noble zinc-based catalysts have paid increasing attention because of low cost and nontoxic,compared with industrial Pt and Cr-based catalysts.However,they often suffer from limited catalytic activity and poor stability.Here,we introduced moderate Ni into ZnO supported Silicalite-1 zeolite to increase catalytic activity and stability simultaneously.Zn^(2+) was the definite active site and NiZn alloy facilitated the sluggish H recombination into H_(2)via reverse spillover.Furthermore,the introduction of Ni increased Lewis acid strength caused by electron transfer from ZnO to NiZn alloy,contributing to improved stability.For resulted 0.5 NiZn/S-1,propene formation rate was 0.18 mol C_(3)H_(6)·(g Zn)^(-1)·h^(-1) at 550℃,which was above 1.5 times higher than that over Zn/S-1 without Ni.Under stability test,the deactivation of0.5 NiZn/S-1 was 0.019 h^(-1),which was only 1/10 of that over Zn/S-1.

Insight into the adsorption behavior and mechanism of trace impurities from H_(2)O_(2)solution on functionalized zirconia by tuning the structure of amino groups

Primary,secondary and tertiary amino-functionalized zirconia(ZrO_(2)-NH_(2),ZrO_(2)-NH and ZrO_(2)-N)was synthesized by the postgrafting method for the adsorption removal of typical metallic ions,phosphate and total oxidizable carbon from a real H_(2)O_(2)solution.ZrO_(2)-NH_(2),ZrO_(2)-NH and ZrO_(2)-N exhibited similar pore sizes and sequentially increased zeta potentials.The adsorption results of single and binary simulated solutions showed that the removal efficiency increased in the order of Fe^(3+)>Al^(3+)>Ca^(2+)>Na^(+).There is competitive adsorption between metallic ions,and Fe^(3+)has an advantage over the other metals,with a removal efficiency of 90.7%.The coexisting phosphate could promote the adsorption of metallic ions,while total oxidizable carbon had no effect on adsorption.The adsorption results of the real H_(2)O_(2)solution showed that ZrO_(2)-NH_(2)exhibited the best adsorption affinity for metallic ions,as did phosphate and total oxidizable carbon,with a total adsorption capacity of 120.9 mg·g_(-1).Density functional theory calculations revealed that the adsorption process of metallic ions involves electron transfer from N atoms to metals and the formation of N-metal bonds.

Observations of equatorial plasma bubbles during the geomagnetic storm of October 2016

We investigated the variations of equatorial plasma bubbles(EPBs)in the East-Asian sector during a strong geomagnetic storm in October 2016,based on observations from the Beidou geostationary(GEO)satellites,Swarm satellite and ground-based ionosonde.Significant nighttime depletions of F region in situ electron density from Swarm and obvious nighttime EPBs in the Beidou GEO observations were observed on 13 October 2016 during the main phase.Moreover,one interesting feature is that the rare and unique sunrise EPBs were triggered on 14 October 2016 in the main phase rather than during the recovery phase as reported by previous studies.In addition,the nighttime EPBs were suppressed during the whole recovery phase,and absent from 14 to 19 October 2016.Meanwhile,the minimum virtual height of F trace(h’F)at Sanya(18.3°N,109.6°E,MLAT 11.1°N)displayed obvious changes during these intervals.The h’F was enhanced in the main phase and declined during the recovery phase,compared with the values at pre-and post-storm.These results indicate that the enhanced nighttime EPBs and sunrise EPBs during the main phase and the absence nighttime EPBs for many days during the recovery phase could be associated with storm-time electric field changes.

Study on Alkaloids in Fructus Hordei Germinatus

[Objectives]To isolate and analyze alkaloids in Fructus Hordei Germinatus.[Methods]The alkaloids in the Fructus Hordei Germinatus were extracted by ultrasonic technology,and analyzed by the ultra-performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS) technique.[Results] According to the mass spectrometry information,compared with the literature reports,the possible structures of seven alkaloids in the Fructus Hordei Germinatus could be inferred.Compounds 1,2 and 3 were organic amine alkaloids,respectively tyramine and N-methyltyramine,hordenine,compounds 4,5,6 and 7 were indole alkaloids,respectively,tryptamine,gramine,harmine,and bufotenidine.The alkaloids in the Fructus Hordei Germinatus were separated by preparative high performance liquid chromatography(p HPLC) technique,a compound was obtained and identified by UPLC-MS/MS and nuclear magnetic resonance(NMR) technique as hordenine.[Conclusions]This experiment is expected to lay a foundation for the development of alkaloids in the Fructus Hordei Germinatus.

First results of optical meteor and meteor trail irregularity from simultaneous Sanya radar and video observations

Meteoroids entering the Earth's atmosphere can create meteor trail irregularity seriously disturbing the background ionosphere. Although numerous observations of meteor trail irregularities were performed with VHF/UHF coherent scatter radars in the past, no simultaneous radar and optical instruments were employed to investigate the characteristics of meteor trail irregularity and its corresponding meteoroid. By installing multiple video cameras near the Sanya VHF radar site, an observational campaign was conducted during the period from November 2016 to February 2017. A total of 242 optical meteors with simultaneous non-specular echoes backscattered from the plasma irregularities generated in the corresponding meteor trails were identified. A good agreement between the angular positions of non-specular echoes derived from the Sanya radar interferometer and those of optical meteors was found,validating that the radar system phase offsets have been properly calibrated. The results also verify the interferometry capability of Sanya radar for meteor trail irregularity observation. The non-specular echoes with simultaneous optical meteors were detected at magnetic aspect angles greater than ~78°. Based on the meteor visual magnitude estimated from the optical data, it was found that the radar nonspecular echoes corresponding to brighter meteors survived for longer duration. This could provide observational evidence for the significance of meteoroid mass on the duration of meteor trail irregularity. On the other hand, the simultaneous radar and video common-volume observations showed that there were some cases with optical meteors but without radar non-specular echoes. One possibility could be that some of the optical meteors appeared at extremely low altitudes where meteor trail irregularities rarely occur.

Multi-instrument study of longitudinal wave structures for plasma bubble seeding in the equatorial ionosphere

Large Scale Wave Structures(LSWS)in the equatorial ionospheric F-region were observed by measuring spatial and temporal variations within detrended total electron content(dTEC)data obtained by ground-based GNSS receivers over the South American continent.By using dTEC-maps,we have been able to produce,for the first-time,two-dimensional representations of LSWS.During the period from September to December,the LSWS frequently occurred starting a few hours prior to Equatorial Plasma Bubble(EPB)development.From 17 events of LSWS observed in 2014 and 2015,wave characteristics were obtained:the observed wavelengths,periods,and the phase speeds are respectively,~900 km,~41 min and~399 m/s;the waves propagated from the northeast to southeast.In some cases the front of the oscillation was meridionally aligned,extending to more than 1600 km,the first time such large extension of the wavefront has been reported.From F-layer bottom height oscillation data,measured by ionosonde,LSWS exhibit two different vertical phase propagation modes,in-phase and downward phase.The former mode indicates the presence of a polarization electric field in the F-layer bottom side;the latter suggests propagation of atmospheric gravity waves.The presence of LSWS near the solar terminator,followed by the development of EPBs,suggests that the upwelling of the F-layer bottom height produces a condition favorable to the development of Rayleigh–Taylor instability.

On the solar activity dependence of midnight equatorial plasma bubbles during June solstice periods

The occurrence of midnight Equatorial Plasma Bubbles(EPBs)during the June solstice period of the ascending phase of solar cycle 24,from 2010 to 2014,was studied using data from the 47 MHz Equatorial Atmosphere Radar(EAR)at Kototabang,Indonesia.The analysis shows that the occurrence of midnight hour EPBs was at its maximum during the low solar activity year 2010 and monotonically decreased thereafter with increasing solar activity.Details of the dependence of midnight hour EPB occurrence on solar activity were investigated using SAMI2 model simulation with a realistic input of E×B drift velocity data obtained from the CINDI-IVM onboard the C/NOFS satellite.Results obtained from term-by-term analysis of the flux tube integrated linear growth rate of RT instability indicate that the formation of a high flux tube electron content height gradient(steep vertical gradient)region at higher altitudes,due to the elevated F layer,is the key factor enhancing the growth rate of RT instability during low solar activity June solstices.Other factors are discussed in light of the relatively weak westward zonal electric field in the presence of the equatorward neutral wind and north-to-south transequatorial wind around the midnight hours of low solar activity June solstices.Also discussed are the initial seeding of RT instability by MSTIDs and how the threshold height required for EPB development varies with solar activity.

Preface to the Special Issue on recent advances in the study of Equatorial Plasma Bubbles and Ionospheric Scintillation

The 2 nd Equatorial Plasma Bubble(EPB)workshop,funded by the Institute of Geology and Geophysics,Chinese Academy of Sciences,and the National Natural Science Foundation of China,took place in Beijing,China during September 13–15,2019.The EPB workshop belongs to a conference series that began in 2016 in Nagoya,Japan at the Institute for Space-Earth Environmental Research,Nagoya University,resulting in a special issue of Progress in Earth and Planetary Science that focused on EPBs.The main goal of the series is to organize in-depth discussion by scientists working on ionospheric irregularities,and solve the scientific challenges in EPB and ionospheric scintillation forecasting.The 2 nd EPB workshop gathered almost 60 scientists from seven countries.A total of 20 invited and contributing papers focusing on ionospheric irregularities and scintillations were presented.Here we briefly comment on 10 papers included in this special issue.

Contribution of the Chinese Meridian Project to space environment research:Highlights and perspectives

The Chinese Meridian Project(CMP)is devoted to establishing a comprehensive ground-based monitoring network for China’s space weather research.CMP is a major national science and technology infrastructure project with the participation of more than 10 research institutions and universities led by the National Space Science Center of the Chinese Academy of Sciences.CMP is planned to be constructed in two phases:CMP phasesⅠandⅡ.The first phase(CMP-Ⅰ)started construction in2008 and completed in 2012,after which it entered the operation stage.The 10-year observation of CMP-Ⅰhas made significant scientific discoveries and achievements in the research fields of the middle and upper atmospheric fluctuations,metal layers in the mesosphere and lower thermosphere,ionospheric disturbances and irregularities,geomagnetic disturbances,and influences of solar activity.The review summarizes the main observations and research achievements,space weather forecast modeling and methods based on CMP-Ⅰover the past 10 years,and presents a future extension perspective along with the construction of CMP-Ⅱ.

Current sensor based on an atomic magnetometer for DC application

A DC current sensor based on an optically pumped atomic magnetometer is proposed.It has a high linearity in a wide operation range,since the magnetometer measures the absolute magnitude of the magnetic field produced by the current to be measured.The current sensor exhibits a high accuracy with a non-moment solenoid and magnetic shielding to suppress the influence from the environment.The absolute error of the measured current is below 0.08 m A when the range is from 7.5 m A to 750 m A.The relative error is 5.54×10^-5 at 750 m A.

Engineering oxygen vacancies on Tb-doped ceria supported Pt catalyst for hydrogen production through steam reforming of long-chain hydrocarbon fuels

Steam reforming of long-chain hydrocarbon fuels for hydrogen production has received great attention for thermal management of the hypersonic vehicle and fuel-cell application.In this work,Pt catalysts supported on CeO_(2)and Tb-doped CeO_(2)were prepared by a precipitation method.The physical structure and chemical properties of the as-prepared catalysts were characterized by powder X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Raman spectroscopy,H_(2)temperature programmed reduction,and X-ray photoelectron spectroscopy.The results show that Tb-doped CeO_(2)supported Pt possesses abundant surface oxygen vacancies,good inhibition of ceria sintering,and strong metal-support interaction compared with CeO_(2)supported Pt.The catalytic performance of hydrogen production via steam reforming of long-chain hydrocarbon fuels(n-dodecane)was tested.Compared with 2Pt/CeO_(2),2Pt/Ce_(0.9)Tb_(0.1)O_(2),and 2Pt/Ce_(0.5)Tb_(0.5)O_(2),the 2Pt/Ce_(0.7)Tb_(0.3)O_(2)has higher activity and stability for hydrogen production,on which the conversion of n-dodecane was maintained at about 53.2%after 600 min reaction under 700℃at liquid space velocity of 9 ml·g^(-1)·h^(-1).2Pt/CeO_(2)rapidly deactivated,the conversion of n-dodecane was reduced to only 41.6%after 600 min.

我国健康建筑发展的现状与展望

中国《健康建筑评价标准》(T/ASC 02-2016)将健康建筑定义为"在满足建筑功能的基础上,为建筑使用者提供更加健康的环境、设施和服务,促进建筑使用者身心健康、实现健康性能提升的建筑".发展健康建筑是建筑领域落实"健康中国"战略部署的重要途径,促进健康建筑发展意义重大.本文首先回顾了健康建筑的发展历程,介绍了我国健康建筑的发展背景.其次,梳理了我国健康建筑在2017~2019年间在标准、科研、组织机构、项目、交流等方面的重点工作和主要成果.最后,对我国健康建筑未来在影响因素、跨学科融合、设计方法、健康改造升级及标准等方面的发展趋势进行了展望.