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Superhydrophobic and corrosion-resistant siloxane-modified MgAl-LDHs coatings on magnesium alloy prepared under mild conditions

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 450-463页

作者： Wenxi Zhang Zhangzelong Zhuo Dan Xu Liang Wu Zhihui Xie Chemical Synthesis and Pollution Control Key laboratory of sichuan province College of Chemistry and Chemical EngineeringChina West Normal UniversityNanchong 637002China College of Materials Science and Engineering/National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China

We have developed a superhydrophobic and corrosion-resistant LDH-W/PFDTMS composite coating on the surface of Mg *** composite comprised a tungstate-intercalated(LDH-W)underlayer that was grown at low temperature(relative to hydrothermal reaction conditions)under atmospheric pressure and an outer polysiloxane layer created from a solution containing perfluorodecyltrimethoxysilane(PFDTMS)using a simple immersion *** successful intercalation of tungstate into the LDH phase and the following formation of the polysiloxane layer were confirmed through X-ray diffraction(XRD),Fourier transform infrared(FTIR)spectroscopy,and X-ray photoelectron spectroscopy(XPS).The corrosion resistance of the LDH-W film,both before and after the PFDTMS modification,was evaluated using electrochemical impedance spectroscopy(EIS),Tafel curves,and immersion *** results showed that Mg coated with LDH-W/PFDTMS exhibited significantly enhanced corrosion protection compared to the unmodified LDHW film,with no apparent signs of corrosion after exposure to 3.5wt%NaCl solution for 15 ***,the LDH-W/PFDTMS coating demonstrated superior superhydrophobicity and self-cleaning properties against water and several common beverages,as confirmed by static contact angle and water-repellency *** results offer valuable insights into preparing superhydrophobic and corrosion-resistant LDH-based composite coatings on Mg alloy surfaces under relatively mild reaction conditions.

关键词： Mg alloy corrosion coating layered double hydroxide

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Main Detrainment Height of Deep Convection Systems over the Tibetan plateau and Its Southern Slope

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Advances in atmospheric Sciences 2019年第10期36卷 1078-1088页

作者： Quanliang CHEN Guolu GAO Yang LI Hongke CAI Xin ZHOU Zhenglin WANG School of atmospheric Sciences Chengdu University of Information Technology and Plateau Atmosphere and Environment Key Laboratory of Sichuan Province

Deep convection systems (DCSs) can rapidly lift water vapor and other pollutants from the lower troposphere to the upper troposphere and lower stratosphere. The main detrainment height determines the level to which the air parcel is lifted. We analyzed the main detrainment height over the Tibetan plateau and its southern slope based on the CloudSat Cloud Profiling Radar 2B_GEOPROF dataset and the Aura Microwave Limb Sounder Level 2 cloud ice product onboard the Atrain constellation of Earth-observing satellites. It was found that the DCSs over the Tibetan plateau and its southern slope have a higher main detrainment height (about 10-16 km) than other regions in the same latitude. The mean main detrainment heights are 12.9 and 13.3 km over the Tibetan plateau and its southern slope, respectively. The cloud ice water path decreases by 16.8% after excluding the influences of DCSs, and the height with the maximum increase in cloud ice water content is located at 178 hPa (about 13 km). The main detrainment height and outflow horizontal range are higher and larger over the central and eastern Tibetan plateau, the west of the southern slope, and the southeastern edge of the Tibetan plateau than that over the northwestern Tibetan plateau. The main detrainment height and outflow horizontal range are lower and broader at nighttime than during daytime.

关键词： main detrainment height deep convection systems Tibetan plateau and its southern slope A-train

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Analysis of the variations in the strength and position of stratospheric sudden warming in the past three decades

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atmospheric and Oceanic Science Letters 2019年第3期12卷 147-154页

作者： ZHANG Ludan CHEN Quanliang College of atmospheric Science Chengdu University of Information Technology and Plateau Atmospheric and Environment Laboratory of Sichuan Province

The authors investigate the statistical features of variations in the strength and position of stratospheric sudden warming (SSW) in the Northern Hemisphere based on ERA-Interim data from 1979 to 2016. It is found that there are 55 SSW events in the past 38 years (average: 1.4 times per year), including 33 major SSW events and 22 minor SSW events. The events mainly occur in February. The variations of the maximum meridional gradient of the zonal mean temperature of the SSW events show increasing trends from 1979 to 1983 and from 1998 to 2011, and decreasing trends from 1984 to 1997 and from 2012 to 2016. However, the linear trend of the variations in the past three decades shows a negative trend. Meanwhile, the strength and duration of major SSW events show similar features. Some SSW events occur at nearly the same time at different levels from 100 hPa to 10 hPa, while others first occur at 10 hPa and then the signal propagates downwards to lower levels. A very interesting phenomenon is that the maximum temperature centers of these 55 SSW events are mainly located over the Eurasian continent between 30°E and 120°E. This may be related to a polar vortex shifting to the Eurasian continent in the past three decades.

关键词： Stratospheric sudden warming meridional gradient zonal mean temperature maximum temperature center

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Factors Influencing Diurnal Variations of Cloud and Precipitation in the Yushu Area of the Tibetan plateau

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Journal of Meteorological Research 2022年第2期36卷 311-325页

作者： Bangjun CAO Shihua LYU Yu ZHANG Xianyu YANG Boliang LI Liang YUAN Meilin LI plateau Atmosphere and environment Key laboratory of sichuan province School of Atmospheric SciencesChengdu University of Information TechnologyChengdu 610225

Using the cloud radar,ground observations,and ECMWF Reanalysis v5(ERA5)data,we investigate the factors influencing nighttime precipitation during summer in the Yushu area of the Tibetan plateau(TP).The cloud top height(CTH),cloud base height(CBH),and liquid water content(LWC)are compared between non-precipitation and precipitation *** results show that the average CTH on precipitation days in Yushu is below 10 km above ground level(AGL)in the daytime,whereas it exceeds 10 km AGL at night,with the maximum at 2300 BT(Beijing Time).The CBH is in-phase with the dewpoint *** precipitation intensity and CTH are in-phase with the *** hourly averaged precipitation intensity and convective available potential energy in ERA5 reach their maximums at2100 BT,which is 3 h ahead of their observed *** is descending motion in the mid day on non-precipitation days,whereas there is ascending motion at night on precipitation *** addition,the horizontal wind direction in the lower level(below 5000 m)shows clockwise rotation from morning to *** shear occurs in the mid level of the atmosphere,accompanied by a subtropical westerly jet in the upper *** difference in horizontal wind speed between 200 and 500 hPa is positively related to the LWC,thereby contributing to the formation of upper-level cloud.

关键词： diurnal variation cloud precipitation Tibetan plateau

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Dynamic and Numerical Study of Waves in the Tibetan plateau Vortex

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Advances in atmospheric Sciences 2014年第1期31卷 131-138页

作者： CHEN Gong LI Guoping Institute of plateau Meteorology China Meteorological Administration College of atmospheric Sciences Chengdu University of Information Technology and The Key Laboratory of Plateau Atmosphere and Environment of Sichuan Province

In terms of its dynamics, The Tibetan plateau Vortex （TPV） is assumed to be a vortex in the botmdary layer forced by diabatic heating and friction. In order to analyze the basic characteristics of waves in the vortex, the governing equations for the vortex were established in column coordinates with the balance of gradient wind. Based on this, the type of mixed waves and their dispersion characteristics were deduced by solving the linear model. Two numerical simulations with triple-nested domains--one idealized large-eddy simulation and one of a TPV that took place on 14 August 2006---were also carried out. The aim of the simulations was to validate the mixed wave deduced from the governing equations. The high-resolution model output data were analyzed and the results showed that the tangential flow field of the TPV in the form of center heating was cyclonic and convergent in the lower levels and anticyclonic and divergent in the upper levels. The simulations also showed that the vorticity of the vortex is uneven and might have shear flow along the radial direction. The changing vorticity causes the formation and spreading of vortex Rossby （VR） waves, and divergence will cause changes to the n^otion of the excitation and evolution of inertial gravity （IG） waves. Therefore, the vortex may contain what we call mixed ：inertial gravity-vortex Rossby （IG-VR） waves. It is suggested that some strongly developed TPVs should be studied in the future, because of their effects on weather in downstream areas.

关键词： Tibetan plateau Vortex thermal forcing tangential flow field mixed inertial gravity-vortex Rossby waves

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Relationship between atmospheric Heat Source over the Tibetan plateau and Precipitation in the sichuan–Chongqing Region during Summer

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Journal of Meteorological Research 2017年第3期31卷 555-566页

作者： Xin LAI Yuanfa GONG College of atmospheric Sciences Chengdu University of Information Technology (CUIT)/Plateau Atmosphere and Environment Key Laboratory of Sichuan Provinceand Joint Laboratory of Climate and Environment Change of CUIT

NCEP-NCAR reanalysis data and a 47-yr daily precipitation dataset from a network of 42 rain gauges are used to analyze the atmospheric heat source （〈Q1〉） anomaly over the Tibetan plateau （TP） and its influence on the summer precipitation anomaly in the sichuan-Chongqing region. Results show that the vertical advection of 〈Ql〉 over the central TP is a major factor affecting summer precipitation in the sichuan-Chongqing region. When the vertical ad- vection of〈Q1〉 over the central TP is strengthened, the South Asian high shifts further than normal to the south and east, the western Pacific subtropical high shifts further than normal to the south and west, and the Indian low weak- ens. This benefits the transport of warm moist air from the low latitude oceans to the sichuan-Chongqing region. Correspondingly, in the high latitudes, two ridges and one trough form, which lead to cool air moving southward. These two air masses converge over the Sicbuan -chongqing region, leading to significant precipitation. In contrast, when the vertical advection of 〈Q1〉 over the central TP is weakened, the South Asian high moves to the north and west, the subtropical high moves eastward and northward, and the Indian low strengthens. This circulation pattern is unfavorable for warm air advection from the south to the sichuan-Chongqing region, and the cool air further north cannot move southward because of the presence of two troughs and one ridge at high latitude. Thus, ascent over the sichuan-Chongqing region is weakened, resulting in less precipitation.

关键词： Tibetan plateau atmospheric heating source/sink sichuan-Chongqing region precipitation variability

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Optical Properties of Cirrus Transition Zones over China Detected by CALIOP

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Journal of Meteorological Research 2017年第3期31卷 576-585页

作者： Hongke CAI Yunfei FU Quanliang CHEN Xiao FENG Xin TIE Ranting TAO Kepiao XU School of atmospheric Science Chengdu University of Information Technology/Plateau Atmospheric and Environment Laboratory of Sichuan Province School of Earth and Space Sciences University of Science and Technology of China

A transition zone near cirrus lateral boundaries can be detected by CALIOP （cloud-aerosol lidar with orthogonal polarization）. In the present study, for such transition zones over China, a number of optical properties, such as the backscatter coefficient and depolarization ratio, showed transitional characteristics between cirrus and clear sky. The stepped horizontal profile showed sharp changes in particle number and morphology between cirrus clouds and clear sky. The color ratio, however, was unable to show cirrus transition features because of the low signal-to-noise ratio. Typical ice particles presented a color ratio of 0.55-1.25 and a depolarization ratio of greater than 0.12, which were significantly higher than those of clear sky. Therefore, optical properties in transition took the form of stepwise hori- zontal profiles. The proportion of typical-featured particles also demonstrated a stepped horizontal profile similar to the optical characteristics, but the relationship between the proportion and the optical characteristics was not uniform in the cirrus clouds, transition zone, and clear sky. Therefore, the optical changes in the transition zone were caused by not only the change in particle concentration, but also the change in the particles themselves. The probability dens- ity distribution of the transition-zone widths showed a positive skewness distribution, and transition zones with widths of 3-5 km occurred most frequently. Overall, transition-zone width decreased with increasing temperature and increased with increasing vertical and horizontal wind speeds. This trend demonstrated independence with the direc- tion of the vertical and horizontal winds. These observations implied that the transitional features were caused by ma- terial exchange, such as entrainment and turbulent transport, near the cirrus lateral boundaries, and by the phase trans- formation of particles, such as sublimation.

关键词： cirrus transition zone lidar temperature wind speed

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Impact of the Urban Heat Island Effect on Ozone Pollution in Chengdu City,China

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Chinese Geographical Science 2023年第6期33卷 1017-1032页

作者： SHI Haoyuan SONG Xingtao ZENG Shenglan plateau Atmosphere and environment Key laboratory of sichuan province Chengdu Plain Urban Meteorology and Environment Observation and Research Station of Sichuan ProvinceSchool of Atmospheric SciencesChengdu University of Information TechnologyChengdu610225China

With the advancement of urbanization,the urban heat island effect and ozone pollution have become hot issues in urban *** urban heat island effect can impact ozone conversion,but its mechanism of action is *** this study,the effects of the urban heat island effect on ozone concentration in Chengdu City,China,were investigated by comparing the ozone concentration under different heat island levels with ozone data from March 2020 to February 2021 and the temperature and wind field data of ERA5-Land during the same *** results showed that:1)regarding the distribution characteristics,the ozone concentration in Chengdu presented a‘high in summer and low in winter’*** ozone concentration in summer(189.54µg/m^(3))was nearly twice that in winter(91.99µg/m^(3)),and the ozone diurnal variation presented a‘single peak and single valley’distribution,with a peak at 16:00.2)For the characteristics of the heat island effect,the heat island intensity in Chengdu was obviously higher in spring than in other seasons,and the diurnal variation showed a‘single peak and single valley’distribution,with the peak and trough values appearing at 9:00 and 17:00,***,the eastern part of Chengdu was a heat island,while the western and northwestern parts were mostly cold island.3)The correlation analysis between heat island intensity and ozone concentration showed a significant positive correlation but with a 7–8 h time *** air temperature was not the main factor affecting ozone *** heat island effect impacts the ozone concentration in two ways:changing the local heat budget to promote ozone generation and forming local urban wind,which promotes ozone diffusion or accumulation and forms different areas of low and high ozone values.

关键词： ozone pollution urban heat island effect heat island intensity lag correlation Chengdu,China

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Indications of stratospheric anomalies in the freezing rain and snow disaster in South China,2008

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Science China Earth Sciences 2011年第8期54卷 1248-1256页

作者： CHEN QuanLiang LI Zhan FAN GuangZhou ZHU KeYun ZHANG Wen ZHU HongQin plateau atmospheric and environment Key laboratory of sichuan province College of Atmospheric Sciences Chengdu University of Information Technology Chengdu 610225 China Institute of Mountain Hazards and environment CAS Chengdu 610041 China

NCEP/NCAR reanalysis data were used to characterize stratospheric temperature and water-vapor anomalies before and after the freezing rain and snow disaster of South China in 2008,and the influence of stratospheric circulation anomalies on the *** temperature and water-vapor anomalies provided good leading indicators of this weather *** period from December 1st 2007 to February 28th 2008 was divided into 18 *** the 6th pentad,temperature decreased significantly at 10 hPa in the near-polar stratospheric region,and the decreasing trend strengthened and extended downward and southward to middle and lower *** the 14th-18th pentads,the temperature decrease reached its maximum and extended to 30°*** coincided with the widespread freezing rain and snow *** the end of January 2008,the temperature decrease ended in the near-polar stratospheric region,but continued in the mid-latitude area of the troposphere as the freezing rain and snow weather *** to the temperature variations,positive anomalies of relative humidity in the stratospheric near-polar region also strengthened and extended downward and southward,coinciding with the freezing rain and snow *** with the significant relationship between the freezing rain and snow disaster and stratospheric circulation anomalies,the stratospheric polar vortex changed its shape in late December,intensifying and spreading downward from the top of the stratosphere and southward to the Asian continent,resulting in a deepening of the East Asian Trough and a strengthening of meridional *** the occurrence of the freezing rain and snow event,temperature and vapor increases in the stratosphere transferred downward to the troposphere,along with a stratospheric flow in the near-polar region southward to lower latitudes.

关键词： freezing rain and snow disasters stratosphere air temperature moisture circulation anomaly

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Seasonal evolution of the effects of the El Nino–Southern Oscillation on lower stratospheric water vapor:Delayed effects in late winter and early spring

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Earth and Planetary Physics 2019年第6期3卷 489-500页

作者： YuJing Liao QuanLiang Chen Xin Zhou School of atmospheric Sciences Chengdu University of Information Technology and Plateau Atmosphere and Environment Key Laboratory of Sichuan Province

Water vapor in the stratosphere makes a significant contribution to global climate change by altering the radiative energy budget of the Earth’s climate *** many previous studies have shown that the El Ni?o–Southern Oscillation(ENSO)has significant effects on the water vapor content of the stratosphere in terms of the annual or seasonal mean,a comprehensive analysis of the seasonal evolution of these effects is still *** reanalysis data and satellite observations,we carried out a composite analysis of the seasonal evolution of stratospheric water vapor during El Ni?o/La Ni?a peaks in winter and decays in *** ENSO has a distinct hysteresis effect on water vapor in the tropical lower *** El Ni?o/La Ni?a events moisten/dry out the tropical lower stratosphere in both winter and spring,whereas this wetting/dehydration effect is more significant in *** pattern is due to a warmer temperature in the upper troposphere and lower stratosphere during the El Ni?o spring phase,which causes more water vapor to enter the stratosphere,and vice versa for La Ni?*** delayed warming/cooling in the lower stratosphere during the El Ni?o/La Ni?a decay in spring leads to the seasonal evolution of ENSO effects on water vapor in the lower stratosphere.

关键词： El Nino-Southern Oscillation stratospheric water vapor seasonal evolution

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