An efficient catalytic system was developed to remove various organic pollutants by simultaneously using low-level cobalt ions,calcium carbonate micro-particles and peroxymonosulfate(PMS).A simple base-induced precipi...An efficient catalytic system was developed to remove various organic pollutants by simultaneously using low-level cobalt ions,calcium carbonate micro-particles and peroxymonosulfate(PMS).A simple base-induced precipitation was used to successfully loaded Co-centered reactive sites onto the surface of CaCO_(3)microparticles.Under optimal conditions at 25°C,10 mg/L methylene blue(MB)could be completely degraded within 10 min with 480μg/L Co^(2+),0.4 g/L CaCO_(3)microparticles(or 0.4 g/L Co@CaCO_(3))and 0.1 g/L PMS.The MB degradation followed the pseudo first order kinetics with a rate constant of 0.583 min^(−1),being 8.3,11.5 and 53.0 times that by using Co-OH(0.07 min^(−1)),Co^(2+)(0.044 min^(−1))and CaCO_(3)(0.011 min^(−1))as the catalyst,respectively.It was confirmed that there was a synergistic effect in the catalytic activity between Co species and the CaCO_(3)particles but the major contributor was the highly dispersed Co species.When Co^(2+)-containing simulated electroplating wastewater was used as the Co^(2+)source,not only the added MB was also completely degraded within 5 min in this catalytic system,but also the coexisting heavy metal ions were substantially removed.The presently developed method was applied to simultaneously treat organic wastewater and heavy metals wastewater.The present method was also successfully used to efficiently degrade other organic pollutants including bisphenol A,sulfamethoxazole,rhodamine B,tetrabromobisphenol A,ofloxacin and benzoic acid.A catalytic mechanism was proposed for the PMS activation by Co@CaCO_(3).The surface of CaCO_(3)particles favors the adsorption of Co^(2+).More importantly,the surface of CaCO_(3)particles provides plentiful surface-OH and-CO_(3)^(2+),and these surface groups complex with Co^(2+)to producemore catalytically active species such as surface[CoOH]^(−),resulting in rapid Co^(2+)/Co^(3+)cycling and electron transfer.These interactions cause the observed synergistic effect between Co species and CaCO_(3)particles in PMS activation.Due to good cycle stability,strong anti-interference ability and wide universality,the new method will have broad application prospects.展开更多
We show that low-level jets(LLJs)occurred in 11 out of 22 radiosonde profiles in late austral summer over the coastal region of the Amundsen Sea Embayment,with ten of the LLJs directed offshore.The LLJs had core speed...We show that low-level jets(LLJs)occurred in 11 out of 22 radiosonde profiles in late austral summer over the coastal region of the Amundsen Sea Embayment,with ten of the LLJs directed offshore.The LLJs had core speeds from 9 to 32 m s^(-1),jet core heights from 80 to 800 m,and were associated with strong,low-level temperature inversions.Seven of the observed offshore LLJs were reasonably simulated by the polar-optimized Weather Research and Forecasting(Polar WRF)model,with output from the model subsequently used to elucidate their generation mechanisms.This study shows that one of the offshore LLJs simulated by the Polar WRF was caused by katabatic winds,while the remaining six were caused by the enhancement of katabatic winds by synoptic forcing in response to a low-pressure system over the Bellingshausen Sea,i.e.,the offshore wind component associated with this system plays a crucial role in the enhancement of the katabatic LLJ.Examination of the Polar WRF output further shows that the LLJs extended over large areas of the Amundsen Sea Embayment,resulting in substantially enhanced near-surface wind speeds over both the Thwaites and Pine Island ice shelves,as well as the open ocean over the continental shelf.The wind-driven forcing associated with the LLJs could perhaps have important impacts on the redistribution of snow over the ice shelves significantly,as well as to affecting sea-ice and ocean circulation variability,including the transport of relatively warm water over the continental shelf to the ice shelf cavities and extension basal melting.展开更多
Objective Evidence that long-term exposure to ambient air pollution increases mortality among older adults,particularly those residing in low-level air pollution locations,remains scarce.This study investigated the po...Objective Evidence that long-term exposure to ambient air pollution increases mortality among older adults,particularly those residing in low-level air pollution locations,remains scarce.This study investigated the potential links between long-term low-level air pollution exposure and mortality among Chinese older adults.Methods A population-based study with 317,464 individuals aged≥65 years was conducted in Shenzhen,China during 2018 and 2020.Logistic regression models were used to analyze the associations between long-term exposure to air pollution and all-cause mortality,as the primary outcome,as well as non-accidental,cancer and cardiovascular mortality.Results Significant associations of PM1,PM_(2.5),PM_(10),SO_(2),CO,and O3 exposures with a higher risk of all-cause mortality were found.Adjusted odds ratio(OR)for each 1μg/m^(3) increment was 1.49[95%confidence interval(CI):1.46,1.53]for PM1,1.30(1.27,1.32)for PM_(2.5),1.05(1.04,1.06)for PM_(10),5.84(5.39,6.32)for SO_(2),1.04(1.04,1.05)for CO,and 1.02(1.00,1.03)for O3,respectively.Long-term PM1,PM_(2.5),PM_(10),SO_(2),and CO exposures also elevated the risks of non-accidental,cancer and cardiovascular mortality.Conclusion Long-term low-level air pollution exposure was associated with an increased mortality risk among Chinese older adults.展开更多
This study examines low-level jets(LLJs)across Northeastern China during both warm(June-September)and cold seasons(December-March)from 1957 to 2021,using fifth generation of the European Centre for Medium-Range Weathe...This study examines low-level jets(LLJs)across Northeastern China during both warm(June-September)and cold seasons(December-March)from 1957 to 2021,using fifth generation of the European Centre for Medium-Range Weather Forecasts reanalysis data with 25-km resolution.LLJs manifest in two prominent regions,one along the leeward flank of the Da Hinggan Ling Mountains in the cold season and another at the center of Northeastern China in the warm season.The intricate interplay between ambient circulation and terrain shapes LLJ distribution,altitudes,wind directions,diurnal cycles,and seasonal diversities.During the warm season,prevailing southwesterly LLJs are found at 925 hPa,while the cold season features stronger and more frequent northwesterly LLJs at 875 hPa.Analysis of the diurnal patterns reveals distinctive behaviors of LLJs in the cold and warm seasons.During the warm season,the single peak in LLJ occurrence emerges around midnight;conversely,in the cold season,LLJs are most frequent shortly before midnight,with an additional sub-peak in the morning.A momentum budget analysis establishes mechanisms underlying these two distinct diurnal variations.In both seasons,the diurnal variation of LLJs is predominately driven by an inertial oscillation and mountain-valley circulations.However,the sub-peak observed in the cold-season morning arises from the thermodynamic and dynamic interaction between the low-level atmosphere and complex terrain.展开更多
In contrast to the Pacific and Atlantic Oceans,the Indian Ocean has lacked in-situ observations of wind profiles over open sea areas for decades.In 2021,a shipborne coherent Doppler lidar(CDL)was used to observe in-si...In contrast to the Pacific and Atlantic Oceans,the Indian Ocean has lacked in-situ observations of wind profiles over open sea areas for decades.In 2021,a shipborne coherent Doppler lidar(CDL)was used to observe in-situ wind profiles in the eastern tropical Indian Ocean.This equipment successfully captured low-level jets(LLJs)in the region,and their characteristics were thoroughly analyzed.Results reveal that the observed wind speed of LLJs in the eastern Indian Ocean ranges from 6 m s^(-1) to 10 m s^(-1) during the boreal winter and spring seasons,showing a height range of 0.6 to 1 km and two peak times at 0800 and 2000 UTC.This wind shear is weaker than that in land or offshore areas,ranging from 0 s^(-1) to 0.006 s^(-1).Moreover,the accuracy of the CDL data is compared to that of ERA5 data in the study area.The results indicate that the zonal wind from ERA5 data significantly deviated from the CDL measurement data,and the overall ERA5 data are substantially weaker than the in-situ observations.Notably,ERA5 underestimates northwestward LLJs.展开更多
Chronic diabetic wounds,a common and severe complication of diabetes,are characterized by their inability to heal due to impaired blood and oxygen supply.In addition to glycemic control,various clinical treatments suc...Chronic diabetic wounds,a common and severe complication of diabetes,are characterized by their inability to heal due to impaired blood and oxygen supply.In addition to glycemic control,various clinical treatments such as wound dressings,hyperbaric oxygen therapy,and phototherapy have been employed to manage these wounds.Low-level light therapy has emerged as an effective,noninvasive,and painless therapeutic approach for wound management.However,the bulkiness of traditional light sources and the need for frequent clinic visits have limited its widespread adoption.We have developed a wearable,flexible light-emitting bandage with cyanobacterial impregnation(LEB@Cyan).The bioactive bandage is designed to provide sustained oxygen generation and robust photobiomodulation,promoting keratinocyte migration,fibroblast proliferation,and angiogenesis.This addresses the hypoxic conditions and enhances bioenergetic supply to accelerate the healing process of diabetic wounds.In detail,the wound area of diabetic rats treated with LEB@Cyan showed significant reductions of 74.76%and 96.32%compared with that of LEB-treated diabetic rats and untreated diabetic rats,respectively.Such self-oxygenated wearable light-emitting fabric holds great promise for future clinical and commercial applications,potentially revolutionizing the management of chronic diabetic wounds.展开更多
In this study,the Betts-Miller-Janjic(BMJ)convective adjustment scheme in the Weather Research and Forecasting(WRF)model version 4.0 was used to investigate the effect of itsα-parameter,which influences the first-gue...In this study,the Betts-Miller-Janjic(BMJ)convective adjustment scheme in the Weather Research and Forecasting(WRF)model version 4.0 was used to investigate the effect of itsα-parameter,which influences the first-guess potential temperature reference profile on the Madden-Julian oscillation(MJO)propagation and structure.This study diagnosed the MJO active phase composites of the MJO-filtered outgoing longwave radiation(OLR)during the December-to-February(DJF)period of 2006-2016 over the Indian Ocean(IO),Maritime Continent(MC),and western Pacific(WP).The results show that the MJO-filtered OLR intensity,propagation pattern,and MJO classification(standing,jumping,and propagating clusters)are sensitive to theα-value,but the phase speeds of propagating MJOs are not.Overall,with an increasingα-value,the simulated MJO-filtered OLR intensity increases,and the simulated propagation pattern is improved.Results also show that the intensity and propagation pattern of an eastward-propagating MJO are associated with MJO circulation structures and thermodynamic structures.Asαincreases,the front Walker cell and the low-level easterly anomaly are enhanced,which premoistens the lower troposphere and triggers more active shallow and congestus clouds.The enhanced shallow and congestus convection preconditions the lower to middle troposphere,accelerating the transition from congestus to deep convection,thereby facilitating eastward propagation of the MJO.Therefore,the simulated MJO tends to transfer from standing to eastward propagating asαincreases.In summary,increasing theα-value is a possible way to improve the simulation of the structure and propagation of the MJO.展开更多
In August 2019,accompanied by an Arctic warming event,elevated thunderstorms crossed over the North Pole(NP)and produced lightning.The northernmost stroke occurred less than 50 km from the NP,marking the closest strok...In August 2019,accompanied by an Arctic warming event,elevated thunderstorms crossed over the North Pole(NP)and produced lightning.The northernmost stroke occurred less than 50 km from the NP,marking the closest stroke to the NP ever recorded.Using ERA5 reanalysis data and satellite observations,we investigated the background and development mechanism of this event.Warm and moist air from low latitudes was transported northward to the vicinity of the North Pole by the 850-h Pa jet,resulting in convergence.Through the combined effects of frontal lifting and the presence of underlying cold air,the warm and moist air was lifted to heights above the melting layer,triggering elevated thunderstorms above the frontal boundary.These findings describe a strong link between warming events and thunderstorms,revealing the formation mechanisms of elevated thunderstorms in the Arctic.In the context of rapid Arctic warming,this study provides preliminary insights into the meteorological conditions conducive to thunderstorm formation in the region.展开更多
The acid leaching residue(ALR)of ionic rare earth(IRE)concentrates containing radioactive elements such as thorium(Th)is classified as low-level radioactive waste.ALR holds valuable strategic resources such as rare ea...The acid leaching residue(ALR)of ionic rare earth(IRE)concentrates containing radioactive elements such as thorium(Th)is classified as low-level radioactive waste.ALR holds valuable strategic resources such as rare earth and Th,while improper long-term heaping storage of ALR poses a substantial environmental risk.This paper proposes a comprehensive process involving low-temperature roasting,hydrochloric acid leaching,single extractant enrichment,and stepwise stripping to recover rare earth elements and thorium from ALR.The achieved leaching efficiencies are 80.11%of LnY,99.43%of Sc(Ⅲ),and 98.67%of Th(Ⅳ)after the carbonization of the organic phase in the ALR through low-temperature roasting.Despite large amounts of acid and impurities present in the leachate,2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester(HEHEHP)still exhibits nearly 100%extraction efficiency for Sc(Ⅲ)and Th(Ⅳ).The effective separation of LnY,Th(Ⅳ),and Sc(Ⅲ)was achieved by implementing fractional extraction enrichment of Th(Ⅳ)and Sc(Ⅲ),followed by Th(Ⅳ)removal through H_(2)SO_(4)and Sc(Ⅲ)removal via NaOH from the loaded organic phase.This scheme successfully achieves a recovery of RE and Th and offers a viable solution for the safe disposal of ALR.展开更多
This study analyzed 10 years of sounding data from Yongxing Island to characterize temperature,humidity,and wind profiles in the atmospheric boundary layer(ABL).Our key findings are as follows.(1)Relative humidity inv...This study analyzed 10 years of sounding data from Yongxing Island to characterize temperature,humidity,and wind profiles in the atmospheric boundary layer(ABL).Our key findings are as follows.(1)Relative humidity inversions(RIs)were the most frequent events(99.8%),followed by surface-based temperature inversions(SBIs,63%),elevated temperature inversions(EIs,50%),and low-level jets(LLJs,41%).(2)Higher near-surface temperature leads to a decrease in EI height,thickness,and intensity.(3)When EIs occurred,RIs were consistently observed beneath the base of the EIs.(4)The intensity of the RIs correlated negatively with surface humidity,whereas the intensity of the LLJs correlated positively with surface winds except in summer.(5)The boundary layer heights(BLHs)are best estimated using the potential temperature gradient method when EIs occur,otherwise,the Richardson number method is the best method.In contrast,the relative humidity and temperature gradient methods exhibit high dispersion or uncertainty.(6)The BLHs showed seasonal variability,peaking in winter(350–1450 m).These findings advance our understanding of ABL dynamics and BLH estimation over tropical islands.展开更多
The Sichuan Basin(SCB),China has a high incidence of extremely persistent heavy rainfall(EPHR)events.The EPHR events from 2009 to 2019 in the SCB were mainly concentrated over the northern and northwestern windward sl...The Sichuan Basin(SCB),China has a high incidence of extremely persistent heavy rainfall(EPHR)events.The EPHR events from 2009 to 2019 in the SCB were mainly concentrated over the northern and northwestern windward slopes and the central basin.They occurred from June to September,but especially in July,and peaked at 0300 LST.ERA5 reanalysis data and objective classification were used to investigate the synoptic patterns and their effects.There were three synoptic patterns during EPHR events,all accompanied by a Southwest Vortex.The location and intensity of the Southwest Vortex,thermal forcing of the Tibetan Plateau(TP),and low-level winds can greatly affect the intensity and spatial distribution of EPHR.When the Southwest Vortex was located in the western SCB and there were southerly low-level jets(LLJs),convergence and upslope wind would lead to EPHR over the northwestern or northern windward slopes.If there was no LLJ and the whole SCB was under the center of the Southwest Vortex,nocturnal EPHR was controlled by the internal circulation of the Southwest Vortex and the updraft generated by the thermal forcing of the TP,and the rainfall was weaker.The southeastern entrance of the SCB was a key area where the low-level wind dominated the nocturnal peak of EPHR.The nocturnal strengthened southeasterly wind in the key area is attributable to inertial oscillation,and the topographic friction plays an essential role in transporting momentum and moisture into the basin by generating easterly and northeasterly ageostrophic winds.展开更多
Starting from the Bay of Bengal storm,based on conventional meteorological data,FY2G meteorological satellite data,EC fine grid data and ERA5 reanalysis data,the first rainstorm process in Dehong Prefecture in the ear...Starting from the Bay of Bengal storm,based on conventional meteorological data,FY2G meteorological satellite data,EC fine grid data and ERA5 reanalysis data,the first rainstorm process in Dehong Prefecture in the early summer of 2024 was analyzed.The results show that the strengthening and northeastward movement of the Bay of Bengal storm"Remal"was the main influencing system for the generation of continuous heavy precipitation in Dehong Prefecture from May 25 to 27,2024.The establishment and strengthening of the low-level southwest jet stream provided better dynamic,water vapor and energy conditions for the generation of this heavy precipitation.The generation and maintenance of rainstorm required the transportation of a steady stream of water vapor to the rainstorm area,and there was strong convergence of water vapor in the rainstorm area.Therefore,in the forecast of summer rainstorm,whether the low-level jet stream is generated or not is very important for the forecast of rainstorm.In addition,there was a good corresponding relationship between the falling area of heavy precipitation,precipitation intensity and duration,and low-level water vapor convergence area.The establishment of southwest monsoon is of great significance to the beginning date of rainy season in Dehong Prefecture.The beginning date of rainy season in Dehong Prefecture was closely related to the first rainstorm process in Dehong Prefecture in early summer.In the future prediction of the beginning date of rainy season in Dehong Prefecture,the first statewide rainstorm process in early summer should be the key point for the prediction.展开更多
Chronic hepatitis B virus(HBV)infection(CHB)is a public health concern worldwide.Current therapies utilizing nucleos(t)ide analogs(NA)have not resulted in a complete cure for CHB.Furthermore,patients on long-term NA t...Chronic hepatitis B virus(HBV)infection(CHB)is a public health concern worldwide.Current therapies utilizing nucleos(t)ide analogs(NA)have not resulted in a complete cure for CHB.Furthermore,patients on long-term NA treatment often develop low-level viremia(LLV).Persistent LLV,in addition to causing the progression of liver disease or hepatocellular carcinoma,may shed light on the current plight of NA therapy.Here,we review the literature on LLV,NA treatment,and various doses of entecavir to find a strategy for improving the efficacy of this antiviral agent.For LLV patients,three therapeutic options are available,switching to another antiviral monotherapy,interferon-αswitching therapy,and continuing monotherapy.In real-world clinical practice,entecavir overdose has been used in antiviral therapy for CHB patients with NA refractory and persistent LLV,which encouraged us to conduct further in-depth literature survey on dosage and duration related entecavir studies.The studies of pharmacodynamics and pharmacokinetics show that entecavir has the maximal selected index for safety,and has great potential in inhibiting HBV replication,in all of the NAs.In the particular section of the drug approval package published by the United States Food and Drug Administration,entecavir doses 2.5-20 mg/d do not increase adverse events,and entecavir doses higher than 1.0 mg/d might improve the antiviral efficacy.The literature survey led us to two suggestions:(1)Increasing entecavir dose to 1.0 mg/d for the treatment of NA naïve patients with HBV DNA>2×106 IU/mL is feasible and would provide better prognosis;and(2)Further research is needed to assess the long-term toxic effects of higher entecavir doses(2.5 and 5.0 mg/d),which may prove beneficial in treating patients with prior NA treatment,partial virological response,or LLV state.展开更多
Three-month wind profiles, 260 m PM_1 concentrations [i.e., particulate matter(PM) with an aerodynamic diameter ≤1μm], and carrier-to-noise ratio data at two Beijing sites 55 km apart(urban and suburban) were collec...Three-month wind profiles, 260 m PM_1 concentrations [i.e., particulate matter(PM) with an aerodynamic diameter ≤1μm], and carrier-to-noise ratio data at two Beijing sites 55 km apart(urban and suburban) were collected to analyze the characteristics of low-level nocturnal wind and PM in autumn and winter. Three mountain-plain wind events with wind shear were selected for analysis. The measurements indicated that the maximum wind speeds of the northerly weak low-level jet(LLJ) below 320 m at the suburban site were weaker than those at the urban site, and the LLJ heights and depths at the suburban site were lower than those at the urban site. The nocturnal 140 m mean vertical velocities and the variations in vertical velocity at the urban site were larger than those at the suburban site. A nocturnal breeze with a weak LLJ of ～3 m s^(-1) noticeably offset nocturnal PM transport due to southerly flow and convergence within the northern urban area of Beijing. Characteristics of the nocturnal LLJ, such as start-up time, structure, intensity, and duration, were important factors in determining the decrease in the nocturnal horizontal range and site-based low-level variations in PM.展开更多
The diurnal variation of precipitation over the Dabie Mountains(DBM) in eastern China during the 2013 mei-yu season is investigated with forecasts of a regional convection-permitting model. Simulated precipitation is ...The diurnal variation of precipitation over the Dabie Mountains(DBM) in eastern China during the 2013 mei-yu season is investigated with forecasts of a regional convection-permitting model. Simulated precipitation is verified against surface rain-gauge observations. The observed morning precipitation peak on the windward(relative to the prevailing synoptic-scale wind) side of the DBM is reproduced with good spatial and temporal accuracy. The interaction between the DBM and a nocturnal boundary layer low-level jet(BLJ) due to the inertial oscillation mechanism is shown to be responsible for this precipitation peak. The BLJ is aligned with the lower-level southwesterly synoptic-scale flow that carries abundant moisture.The BLJ core is established at around 0200 LST upwind of the mountains. It moves towards the DBM and reaches maximum intensity at about 70 km ahead of the mountains. When the BLJ impinges upon the windward side of the DBM in the early morning, mechanical lifting of moist air leads to condensation and subsequent precipitation.展开更多
An extremely heavy rainfall event lasting from 17 to 22 July 2021 occurred in Henan Province of China, with accumulated precipitation of more than 1000 mm over a 6-day period that exceeded its mean annual precipitatio...An extremely heavy rainfall event lasting from 17 to 22 July 2021 occurred in Henan Province of China, with accumulated precipitation of more than 1000 mm over a 6-day period that exceeded its mean annual precipitation. The present study examines the roles of persistent low-level jets(LLJs) in maintaining the precipitation using surface station observations and reanalysis datasets. The LLJs triggered strong ascending motions and carried moisture mainly from the outflow of Typhoon In-fa(2021). The varying directions of the LLJs well corresponded to the meridional shifts of the rainfall. The precipitation rate reached a maximum during 20-21 July as the LLJs strengthened and expanded vertically into double LLJs, including synoptic-weather-system-related LLJs(SLLJs) at 850–700 hPa and boundary-layer jets(BLJs)at ~950 hPa. The coupling of the SLLJ and BLJ provided strong mid-and low-level convergence on 20 July, whereas the SLLJ produced mid-level divergence at its entrance that coupled with low-level convergence at the terminus of the BLJ on21 July. The formation mechanisms of the two types of LLJs are further examined. The SLLJs and the low-pressure vortex(or inverted trough) varied synchronously as a whole and were affected by the southwestward movement of the WPSH in the rainiest period. The persistent large total pressure gradient force at low levels also maintained the strength of low-level geostrophic winds, thus sustaining the BLJs on the synoptic scale. The results based on a Du-Rotunno 1D model show that the Blackadar and Holton mechanisms jointly governed the BLJ dynamics on the diurnal scale.展开更多
Two novel thermal cycles based on Brayton cycle and Rankine cycle are proposed, respectively, which integrate the recovery of low-level waste heat and Liquefied Nature Gas （LNG） cold energy utilization for power gen...Two novel thermal cycles based on Brayton cycle and Rankine cycle are proposed, respectively, which integrate the recovery of low-level waste heat and Liquefied Nature Gas （LNG） cold energy utilization for power generation. Cascade utilization of energy is realized in the two thermal cycles, where low-level waste heat,low-temperature exergy and pressure exergy of LNG are utilized efficiently through the system synthesis. The simulations are carried out using the commercial Aspen Plus 10.2, and the results are analyzed. Compared with the conventional Brayton cycle and Rankine cycle, the two novel cycles bring 60.94% and 60% in exergy efficiency, respectively and 53.08% and 52.31% in thermal efficiency, respectively.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22076052 and 21976063)China Postdoctoral Science Foundation(No.2018M642850)the Research Funding of Wuhan Polytechnic University(No.2023RZ017).
文摘An efficient catalytic system was developed to remove various organic pollutants by simultaneously using low-level cobalt ions,calcium carbonate micro-particles and peroxymonosulfate(PMS).A simple base-induced precipitation was used to successfully loaded Co-centered reactive sites onto the surface of CaCO_(3)microparticles.Under optimal conditions at 25°C,10 mg/L methylene blue(MB)could be completely degraded within 10 min with 480μg/L Co^(2+),0.4 g/L CaCO_(3)microparticles(or 0.4 g/L Co@CaCO_(3))and 0.1 g/L PMS.The MB degradation followed the pseudo first order kinetics with a rate constant of 0.583 min^(−1),being 8.3,11.5 and 53.0 times that by using Co-OH(0.07 min^(−1)),Co^(2+)(0.044 min^(−1))and CaCO_(3)(0.011 min^(−1))as the catalyst,respectively.It was confirmed that there was a synergistic effect in the catalytic activity between Co species and the CaCO_(3)particles but the major contributor was the highly dispersed Co species.When Co^(2+)-containing simulated electroplating wastewater was used as the Co^(2+)source,not only the added MB was also completely degraded within 5 min in this catalytic system,but also the coexisting heavy metal ions were substantially removed.The presently developed method was applied to simultaneously treat organic wastewater and heavy metals wastewater.The present method was also successfully used to efficiently degrade other organic pollutants including bisphenol A,sulfamethoxazole,rhodamine B,tetrabromobisphenol A,ofloxacin and benzoic acid.A catalytic mechanism was proposed for the PMS activation by Co@CaCO_(3).The surface of CaCO_(3)particles favors the adsorption of Co^(2+).More importantly,the surface of CaCO_(3)particles provides plentiful surface-OH and-CO_(3)^(2+),and these surface groups complex with Co^(2+)to producemore catalytically active species such as surface[CoOH]^(−),resulting in rapid Co^(2+)/Co^(3+)cycling and electron transfer.These interactions cause the observed synergistic effect between Co species and CaCO_(3)particles in PMS activation.Due to good cycle stability,strong anti-interference ability and wide universality,the new method will have broad application prospects.
基金support from the European Union’s Horizon 2020 research and innovation framework program under Grant No.101003590(PolarRES)funding from the Indian Institute of Technology Kharagpur and the Ministry of Education,Government of India。
文摘We show that low-level jets(LLJs)occurred in 11 out of 22 radiosonde profiles in late austral summer over the coastal region of the Amundsen Sea Embayment,with ten of the LLJs directed offshore.The LLJs had core speeds from 9 to 32 m s^(-1),jet core heights from 80 to 800 m,and were associated with strong,low-level temperature inversions.Seven of the observed offshore LLJs were reasonably simulated by the polar-optimized Weather Research and Forecasting(Polar WRF)model,with output from the model subsequently used to elucidate their generation mechanisms.This study shows that one of the offshore LLJs simulated by the Polar WRF was caused by katabatic winds,while the remaining six were caused by the enhancement of katabatic winds by synoptic forcing in response to a low-pressure system over the Bellingshausen Sea,i.e.,the offshore wind component associated with this system plays a crucial role in the enhancement of the katabatic LLJ.Examination of the Polar WRF output further shows that the LLJs extended over large areas of the Amundsen Sea Embayment,resulting in substantially enhanced near-surface wind speeds over both the Thwaites and Pine Island ice shelves,as well as the open ocean over the continental shelf.The wind-driven forcing associated with the LLJs could perhaps have important impacts on the redistribution of snow over the ice shelves significantly,as well as to affecting sea-ice and ocean circulation variability,including the transport of relatively warm water over the continental shelf to the ice shelf cavities and extension basal melting.
基金supported by the National Natural Science Foundation of China(grant no.82273631)the Science and Technology Planning Project of Shenzhen City,Guangdong Province,China(grant no.JCYJ20220531094410024)the Shenzhen Medical Key Discipline Construction Fund,Guangdong Province,China(grant no.SZXK065).
文摘Objective Evidence that long-term exposure to ambient air pollution increases mortality among older adults,particularly those residing in low-level air pollution locations,remains scarce.This study investigated the potential links between long-term low-level air pollution exposure and mortality among Chinese older adults.Methods A population-based study with 317,464 individuals aged≥65 years was conducted in Shenzhen,China during 2018 and 2020.Logistic regression models were used to analyze the associations between long-term exposure to air pollution and all-cause mortality,as the primary outcome,as well as non-accidental,cancer and cardiovascular mortality.Results Significant associations of PM1,PM_(2.5),PM_(10),SO_(2),CO,and O3 exposures with a higher risk of all-cause mortality were found.Adjusted odds ratio(OR)for each 1μg/m^(3) increment was 1.49[95%confidence interval(CI):1.46,1.53]for PM1,1.30(1.27,1.32)for PM_(2.5),1.05(1.04,1.06)for PM_(10),5.84(5.39,6.32)for SO_(2),1.04(1.04,1.05)for CO,and 1.02(1.00,1.03)for O3,respectively.Long-term PM1,PM_(2.5),PM_(10),SO_(2),and CO exposures also elevated the risks of non-accidental,cancer and cardiovascular mortality.Conclusion Long-term low-level air pollution exposure was associated with an increased mortality risk among Chinese older adults.
基金supported by the National Natural Science Foundation of China(Grant Nos.42122033,42205005,42075006,and 42475002)the Basic Research and Operation Funding of the Chinese Academy of Meteorological Sciences(Grant No.2022Y009)+1 种基金the Key Innovation Team of China Meteorological Administration(CMA2023ZD08)the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.316323005).
文摘This study examines low-level jets(LLJs)across Northeastern China during both warm(June-September)and cold seasons(December-March)from 1957 to 2021,using fifth generation of the European Centre for Medium-Range Weather Forecasts reanalysis data with 25-km resolution.LLJs manifest in two prominent regions,one along the leeward flank of the Da Hinggan Ling Mountains in the cold season and another at the center of Northeastern China in the warm season.The intricate interplay between ambient circulation and terrain shapes LLJ distribution,altitudes,wind directions,diurnal cycles,and seasonal diversities.During the warm season,prevailing southwesterly LLJs are found at 925 hPa,while the cold season features stronger and more frequent northwesterly LLJs at 875 hPa.Analysis of the diurnal patterns reveals distinctive behaviors of LLJs in the cold and warm seasons.During the warm season,the single peak in LLJ occurrence emerges around midnight;conversely,in the cold season,LLJs are most frequent shortly before midnight,with an additional sub-peak in the morning.A momentum budget analysis establishes mechanisms underlying these two distinct diurnal variations.In both seasons,the diurnal variation of LLJs is predominately driven by an inertial oscillation and mountain-valley circulations.However,the sub-peak observed in the cold-season morning arises from the thermodynamic and dynamic interaction between the low-level atmosphere and complex terrain.
基金supported by the Taishan Scholars Programs of Shandong Province(No.tsqn201909165)the Global Change and Air-Sea Interaction Program(Nos.GASI-04-QYQH-03,GASI-01-WIND-STwin)the National Natural Science Foundation of China(Nos.41876028,42349910).
文摘In contrast to the Pacific and Atlantic Oceans,the Indian Ocean has lacked in-situ observations of wind profiles over open sea areas for decades.In 2021,a shipborne coherent Doppler lidar(CDL)was used to observe in-situ wind profiles in the eastern tropical Indian Ocean.This equipment successfully captured low-level jets(LLJs)in the region,and their characteristics were thoroughly analyzed.Results reveal that the observed wind speed of LLJs in the eastern Indian Ocean ranges from 6 m s^(-1) to 10 m s^(-1) during the boreal winter and spring seasons,showing a height range of 0.6 to 1 km and two peak times at 0800 and 2000 UTC.This wind shear is weaker than that in land or offshore areas,ranging from 0 s^(-1) to 0.006 s^(-1).Moreover,the accuracy of the CDL data is compared to that of ERA5 data in the study area.The results indicate that the zonal wind from ERA5 data significantly deviated from the CDL measurement data,and the overall ERA5 data are substantially weaker than the in-situ observations.Notably,ERA5 underestimates northwestward LLJs.
基金supported by the National Natural Science Foundation of China[Grant Nos.52375414(L.K.)and 82372121(M.H.)]the Shanghai Science&Technology Committee Innovation Grant[Grant No.23ZR1404200(L.K.)]the Yiwu Research Institute of Fudan University(L.K.),and the Shanghai Rising-Star Program[Grant No.23QA1409500 H.)].
文摘Chronic diabetic wounds,a common and severe complication of diabetes,are characterized by their inability to heal due to impaired blood and oxygen supply.In addition to glycemic control,various clinical treatments such as wound dressings,hyperbaric oxygen therapy,and phototherapy have been employed to manage these wounds.Low-level light therapy has emerged as an effective,noninvasive,and painless therapeutic approach for wound management.However,the bulkiness of traditional light sources and the need for frequent clinic visits have limited its widespread adoption.We have developed a wearable,flexible light-emitting bandage with cyanobacterial impregnation(LEB@Cyan).The bioactive bandage is designed to provide sustained oxygen generation and robust photobiomodulation,promoting keratinocyte migration,fibroblast proliferation,and angiogenesis.This addresses the hypoxic conditions and enhances bioenergetic supply to accelerate the healing process of diabetic wounds.In detail,the wound area of diabetic rats treated with LEB@Cyan showed significant reductions of 74.76%and 96.32%compared with that of LEB-treated diabetic rats and untreated diabetic rats,respectively.Such self-oxygenated wearable light-emitting fabric holds great promise for future clinical and commercial applications,potentially revolutionizing the management of chronic diabetic wounds.
基金supported by the National Natural Science Foundation of China(Grant Nos.41975090,U2242201,42075077)the Natural Science Foundation of Hunan Province,China(2022JJ20043)the Science and Technology Innovation Program of Hunan Province,China(2022RC1239)。
文摘In this study,the Betts-Miller-Janjic(BMJ)convective adjustment scheme in the Weather Research and Forecasting(WRF)model version 4.0 was used to investigate the effect of itsα-parameter,which influences the first-guess potential temperature reference profile on the Madden-Julian oscillation(MJO)propagation and structure.This study diagnosed the MJO active phase composites of the MJO-filtered outgoing longwave radiation(OLR)during the December-to-February(DJF)period of 2006-2016 over the Indian Ocean(IO),Maritime Continent(MC),and western Pacific(WP).The results show that the MJO-filtered OLR intensity,propagation pattern,and MJO classification(standing,jumping,and propagating clusters)are sensitive to theα-value,but the phase speeds of propagating MJOs are not.Overall,with an increasingα-value,the simulated MJO-filtered OLR intensity increases,and the simulated propagation pattern is improved.Results also show that the intensity and propagation pattern of an eastward-propagating MJO are associated with MJO circulation structures and thermodynamic structures.Asαincreases,the front Walker cell and the low-level easterly anomaly are enhanced,which premoistens the lower troposphere and triggers more active shallow and congestus clouds.The enhanced shallow and congestus convection preconditions the lower to middle troposphere,accelerating the transition from congestus to deep convection,thereby facilitating eastward propagation of the MJO.Therefore,the simulated MJO tends to transfer from standing to eastward propagating asαincreases.In summary,increasing theα-value is a possible way to improve the simulation of the structure and propagation of the MJO.
基金supported by the National Key Research and Development Program of China(2023YFC3007703)National Natural Science Foundation of China(Grant Nos.41675066,42394122)+1 种基金CAS Project of Stable Support for Youth Team in Basic Research Field(YSRR-018)the Chinese Meridian Project。
文摘In August 2019,accompanied by an Arctic warming event,elevated thunderstorms crossed over the North Pole(NP)and produced lightning.The northernmost stroke occurred less than 50 km from the NP,marking the closest stroke to the NP ever recorded.Using ERA5 reanalysis data and satellite observations,we investigated the background and development mechanism of this event.Warm and moist air from low latitudes was transported northward to the vicinity of the North Pole by the 850-h Pa jet,resulting in convergence.Through the combined effects of frontal lifting and the presence of underlying cold air,the warm and moist air was lifted to heights above the melting layer,triggering elevated thunderstorms above the frontal boundary.These findings describe a strong link between warming events and thunderstorms,revealing the formation mechanisms of elevated thunderstorms in the Arctic.In the context of rapid Arctic warming,this study provides preliminary insights into the meteorological conditions conducive to thunderstorm formation in the region.
基金supported by the National Key Research and Development Program of China(2020YFC1909001)the Natural Science Foundation of Jiangxi Province(20202BABL214024)。
文摘The acid leaching residue(ALR)of ionic rare earth(IRE)concentrates containing radioactive elements such as thorium(Th)is classified as low-level radioactive waste.ALR holds valuable strategic resources such as rare earth and Th,while improper long-term heaping storage of ALR poses a substantial environmental risk.This paper proposes a comprehensive process involving low-temperature roasting,hydrochloric acid leaching,single extractant enrichment,and stepwise stripping to recover rare earth elements and thorium from ALR.The achieved leaching efficiencies are 80.11%of LnY,99.43%of Sc(Ⅲ),and 98.67%of Th(Ⅳ)after the carbonization of the organic phase in the ALR through low-temperature roasting.Despite large amounts of acid and impurities present in the leachate,2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester(HEHEHP)still exhibits nearly 100%extraction efficiency for Sc(Ⅲ)and Th(Ⅳ).The effective separation of LnY,Th(Ⅳ),and Sc(Ⅲ)was achieved by implementing fractional extraction enrichment of Th(Ⅳ)and Sc(Ⅲ),followed by Th(Ⅳ)removal through H_(2)SO_(4)and Sc(Ⅲ)removal via NaOH from the loaded organic phase.This scheme successfully achieves a recovery of RE and Th and offers a viable solution for the safe disposal of ALR.
基金National Key Research and Development Program of China(2023YFC3008002)National Natural Science Foundation of China(U21A6001,42075059)Key Laboratory of Guangdong Province(2020B1212060025)。
文摘This study analyzed 10 years of sounding data from Yongxing Island to characterize temperature,humidity,and wind profiles in the atmospheric boundary layer(ABL).Our key findings are as follows.(1)Relative humidity inversions(RIs)were the most frequent events(99.8%),followed by surface-based temperature inversions(SBIs,63%),elevated temperature inversions(EIs,50%),and low-level jets(LLJs,41%).(2)Higher near-surface temperature leads to a decrease in EI height,thickness,and intensity.(3)When EIs occurred,RIs were consistently observed beneath the base of the EIs.(4)The intensity of the RIs correlated negatively with surface humidity,whereas the intensity of the LLJs correlated positively with surface winds except in summer.(5)The boundary layer heights(BLHs)are best estimated using the potential temperature gradient method when EIs occur,otherwise,the Richardson number method is the best method.In contrast,the relative humidity and temperature gradient methods exhibit high dispersion or uncertainty.(6)The BLHs showed seasonal variability,peaking in winter(350–1450 m).These findings advance our understanding of ABL dynamics and BLH estimation over tropical islands.
基金supported by the National Natural Science Foundation of China(Grant Nos.42330610 and 42075010)。
文摘The Sichuan Basin(SCB),China has a high incidence of extremely persistent heavy rainfall(EPHR)events.The EPHR events from 2009 to 2019 in the SCB were mainly concentrated over the northern and northwestern windward slopes and the central basin.They occurred from June to September,but especially in July,and peaked at 0300 LST.ERA5 reanalysis data and objective classification were used to investigate the synoptic patterns and their effects.There were three synoptic patterns during EPHR events,all accompanied by a Southwest Vortex.The location and intensity of the Southwest Vortex,thermal forcing of the Tibetan Plateau(TP),and low-level winds can greatly affect the intensity and spatial distribution of EPHR.When the Southwest Vortex was located in the western SCB and there were southerly low-level jets(LLJs),convergence and upslope wind would lead to EPHR over the northwestern or northern windward slopes.If there was no LLJ and the whole SCB was under the center of the Southwest Vortex,nocturnal EPHR was controlled by the internal circulation of the Southwest Vortex and the updraft generated by the thermal forcing of the TP,and the rainfall was weaker.The southeastern entrance of the SCB was a key area where the low-level wind dominated the nocturnal peak of EPHR.The nocturnal strengthened southeasterly wind in the key area is attributable to inertial oscillation,and the topographic friction plays an essential role in transporting momentum and moisture into the basin by generating easterly and northeasterly ageostrophic winds.
基金Supported by the"Short,Simple and Fast"Project of Meteorological Science and Technology of Dehong Prefecture(DPK2024-01).
文摘Starting from the Bay of Bengal storm,based on conventional meteorological data,FY2G meteorological satellite data,EC fine grid data and ERA5 reanalysis data,the first rainstorm process in Dehong Prefecture in the early summer of 2024 was analyzed.The results show that the strengthening and northeastward movement of the Bay of Bengal storm"Remal"was the main influencing system for the generation of continuous heavy precipitation in Dehong Prefecture from May 25 to 27,2024.The establishment and strengthening of the low-level southwest jet stream provided better dynamic,water vapor and energy conditions for the generation of this heavy precipitation.The generation and maintenance of rainstorm required the transportation of a steady stream of water vapor to the rainstorm area,and there was strong convergence of water vapor in the rainstorm area.Therefore,in the forecast of summer rainstorm,whether the low-level jet stream is generated or not is very important for the forecast of rainstorm.In addition,there was a good corresponding relationship between the falling area of heavy precipitation,precipitation intensity and duration,and low-level water vapor convergence area.The establishment of southwest monsoon is of great significance to the beginning date of rainy season in Dehong Prefecture.The beginning date of rainy season in Dehong Prefecture was closely related to the first rainstorm process in Dehong Prefecture in early summer.In the future prediction of the beginning date of rainy season in Dehong Prefecture,the first statewide rainstorm process in early summer should be the key point for the prediction.
文摘Chronic hepatitis B virus(HBV)infection(CHB)is a public health concern worldwide.Current therapies utilizing nucleos(t)ide analogs(NA)have not resulted in a complete cure for CHB.Furthermore,patients on long-term NA treatment often develop low-level viremia(LLV).Persistent LLV,in addition to causing the progression of liver disease or hepatocellular carcinoma,may shed light on the current plight of NA therapy.Here,we review the literature on LLV,NA treatment,and various doses of entecavir to find a strategy for improving the efficacy of this antiviral agent.For LLV patients,three therapeutic options are available,switching to another antiviral monotherapy,interferon-αswitching therapy,and continuing monotherapy.In real-world clinical practice,entecavir overdose has been used in antiviral therapy for CHB patients with NA refractory and persistent LLV,which encouraged us to conduct further in-depth literature survey on dosage and duration related entecavir studies.The studies of pharmacodynamics and pharmacokinetics show that entecavir has the maximal selected index for safety,and has great potential in inhibiting HBV replication,in all of the NAs.In the particular section of the drug approval package published by the United States Food and Drug Administration,entecavir doses 2.5-20 mg/d do not increase adverse events,and entecavir doses higher than 1.0 mg/d might improve the antiviral efficacy.The literature survey led us to two suggestions:(1)Increasing entecavir dose to 1.0 mg/d for the treatment of NA naïve patients with HBV DNA>2×106 IU/mL is feasible and would provide better prognosis;and(2)Further research is needed to assess the long-term toxic effects of higher entecavir doses(2.5 and 5.0 mg/d),which may prove beneficial in treating patients with prior NA treatment,partial virological response,or LLV state.
基金supported by the National Key R&D Program of China (Grant No.2017YFC0209801)the National Natural Science Foundation of China (Grant Nos.41505091,91544221,41675137,41575124 and 41505116)
文摘Three-month wind profiles, 260 m PM_1 concentrations [i.e., particulate matter(PM) with an aerodynamic diameter ≤1μm], and carrier-to-noise ratio data at two Beijing sites 55 km apart(urban and suburban) were collected to analyze the characteristics of low-level nocturnal wind and PM in autumn and winter. Three mountain-plain wind events with wind shear were selected for analysis. The measurements indicated that the maximum wind speeds of the northerly weak low-level jet(LLJ) below 320 m at the suburban site were weaker than those at the urban site, and the LLJ heights and depths at the suburban site were lower than those at the urban site. The nocturnal 140 m mean vertical velocities and the variations in vertical velocity at the urban site were larger than those at the suburban site. A nocturnal breeze with a weak LLJ of ～3 m s^(-1) noticeably offset nocturnal PM transport due to southerly flow and convergence within the northern urban area of Beijing. Characteristics of the nocturnal LLJ, such as start-up time, structure, intensity, and duration, were important factors in determining the decrease in the nocturnal horizontal range and site-based low-level variations in PM.
基金supported by the Special Foundation of the China Meteorological Administration (Grant No.GYHY201506006)supported by the National Science Foundation of China (Grant Nos.41405100,41322032 and 41275031)
文摘The diurnal variation of precipitation over the Dabie Mountains(DBM) in eastern China during the 2013 mei-yu season is investigated with forecasts of a regional convection-permitting model. Simulated precipitation is verified against surface rain-gauge observations. The observed morning precipitation peak on the windward(relative to the prevailing synoptic-scale wind) side of the DBM is reproduced with good spatial and temporal accuracy. The interaction between the DBM and a nocturnal boundary layer low-level jet(BLJ) due to the inertial oscillation mechanism is shown to be responsible for this precipitation peak. The BLJ is aligned with the lower-level southwesterly synoptic-scale flow that carries abundant moisture.The BLJ core is established at around 0200 LST upwind of the mountains. It moves towards the DBM and reaches maximum intensity at about 70 km ahead of the mountains. When the BLJ impinges upon the windward side of the DBM in the early morning, mechanical lifting of moist air leads to condensation and subsequent precipitation.
基金supported by Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)the National Natural Science Foundation of China(Grant Nos.42122033,41875055,and 42075006)Guangzhou Science and Technology Plan Projects(202002030346 and 202002030196).
文摘An extremely heavy rainfall event lasting from 17 to 22 July 2021 occurred in Henan Province of China, with accumulated precipitation of more than 1000 mm over a 6-day period that exceeded its mean annual precipitation. The present study examines the roles of persistent low-level jets(LLJs) in maintaining the precipitation using surface station observations and reanalysis datasets. The LLJs triggered strong ascending motions and carried moisture mainly from the outflow of Typhoon In-fa(2021). The varying directions of the LLJs well corresponded to the meridional shifts of the rainfall. The precipitation rate reached a maximum during 20-21 July as the LLJs strengthened and expanded vertically into double LLJs, including synoptic-weather-system-related LLJs(SLLJs) at 850–700 hPa and boundary-layer jets(BLJs)at ~950 hPa. The coupling of the SLLJ and BLJ provided strong mid-and low-level convergence on 20 July, whereas the SLLJ produced mid-level divergence at its entrance that coupled with low-level convergence at the terminus of the BLJ on21 July. The formation mechanisms of the two types of LLJs are further examined. The SLLJs and the low-pressure vortex(or inverted trough) varied synchronously as a whole and were affected by the southwestward movement of the WPSH in the rainiest period. The persistent large total pressure gradient force at low levels also maintained the strength of low-level geostrophic winds, thus sustaining the BLJs on the synoptic scale. The results based on a Du-Rotunno 1D model show that the Blackadar and Holton mechanisms jointly governed the BLJ dynamics on the diurnal scale.
基金the Science and Technology Foundation of Shaanxi Province (No.2002K08-G9).
文摘Two novel thermal cycles based on Brayton cycle and Rankine cycle are proposed, respectively, which integrate the recovery of low-level waste heat and Liquefied Nature Gas （LNG） cold energy utilization for power generation. Cascade utilization of energy is realized in the two thermal cycles, where low-level waste heat,low-temperature exergy and pressure exergy of LNG are utilized efficiently through the system synthesis. The simulations are carried out using the commercial Aspen Plus 10.2, and the results are analyzed. Compared with the conventional Brayton cycle and Rankine cycle, the two novel cycles bring 60.94% and 60% in exergy efficiency, respectively and 53.08% and 52.31% in thermal efficiency, respectively.
