Electrical characteristics of an isolated supercell storm observed on 13 June 2014 over Beijing were investigated using lightning data obtained from the Beijing Lightning Network,radar reflectivity,and hydrometeor ret...Electrical characteristics of an isolated supercell storm observed on 13 June 2014 over Beijing were investigated using lightning data obtained from the Beijing Lightning Network,radar reflectivity,and hydrometeor retrievals during the 6-h lifetime.Positive cloud-to-ground(+CG)lightning took a high percentage of CG lightning.Before and during a hail event,+CG lightning was more frequent than negative cloud-to-ground(-CG)lightning,except that+CG lightning took a high percentage at the beginning and in the dissipating stage.After the hail event ended,-CG lightning dominated and reached its maximum value.An analysis of hydrometeors retrieved by X-band polarimetric radar revealed that the discharge concentrated in the convective region with graupel particles and hailstones,whereas graupel,snow and ice crystals in the stratiform region.Lightning radiation sources were located mainly in the convective region,some of which were distributed along a gradient of radar reflectivity from the convective region to the stratiform region.The indication is that the supercell demonstrated an inverted tripole charge structure before the hail event,which converted to a normal tripole structure after the hail event.展开更多
A thunderstorm tracking algorithm is proposed to nowcast the possibility of lightning activity over an area of concern by using the total lightning data and neighborhood technique.The lightning radiation sources obser...A thunderstorm tracking algorithm is proposed to nowcast the possibility of lightning activity over an area of concern by using the total lightning data and neighborhood technique.The lightning radiation sources observed from the Beijing Lightning Network(BLNET)were used to obtain information about the thunderstorm cells,which are significantly valuable in real-time.The boundaries of thunderstorm cells were obtained through the neighborhood technique.After smoothing,these boundaries were used to track the movement of thunderstorms and then extrapolated to nowcast the lightning approaching in an area of concern.The algorithm can deliver creditable results prior to a thunderstorm arriving at the area of concern,with accuracies of 63%,80%,and 91%for lead times of 30,15,and 5 minutes,respectively.The real-time observations of total lightning appear to be significant for thunderstorm tracking and lightning nowcasting,as total lightning tracking could help to fill the observational gaps in radar reflectivity due to the attenuation by hills or other obstacles.The lightning data used in the algorithm performs well in tracking the active thunderstorm cells associated with lightning activities.展开更多
Atmospheric electricity is composed of a series of electric phenomena in the atmosphere.Significant advances in atmospheric electricity research conducted in China have been achieved in recent years.In this paper,the ...Atmospheric electricity is composed of a series of electric phenomena in the atmosphere.Significant advances in atmospheric electricity research conducted in China have been achieved in recent years.In this paper,the research progress on atmospheric electricity achieved in China during 2019-22 is reviewed focusing on the following aspects:(1)lightning detection and location techniques,(2)thunderstorm electricity,(3)lightning forecasting methods and techniques,(4)physical processes of lightning discharge,(5)high energy emissions and effects of thunderstorms on the upper atmosphere,and(6)the effect of aerosol on lightning.展开更多
Platinum and zinc containing LTA zeolite catalysts with tunable meso/microporosity were prepared by using ligand-metal precursors under hydrothermal condition. These materials were employed for oxidation of ethane to ...Platinum and zinc containing LTA zeolite catalysts with tunable meso/microporosity were prepared by using ligand-metal precursors under hydrothermal condition. These materials were employed for oxidation of ethane to oxygenates using hydrogen peroxides as oxidant under mild reaction condition. The results showed that platinum and zinc loaded LTA zeolites were effective for the partial oxidation of ethane with hydrogen peroxide giving the desired C_2 oxygenates. Moreover, the C_1 oxygenates were also obtained through subsequent C–C bond scission pathways. The over oxidation of ethanol/methanol to acetic acid/formic acid could be inhibited through the introduction of mesoporosity in LTA zeolites. Our findings for oxidation of ethane suggested that the selectivity to the oxidation products such as alcohols and acids could be tailored by tuning the metal species within the LTA zeolites and porosity of catalysts, indicating that a balance between the meso/microporosity and metal species in LTA zeolites can be realized for desirable catalysis by one-pot synthesis of zeolites. In addition, the selectivity to oxygenates can also be tuned by control of the reaction conditions, i.e. concentration of hydrogen peroxide or reaction time.展开更多
The Dynamical-microphysical-electrical Processes in Severe Thunderstorms and Lightning Hazards(STORM973)project conducted coordinated comprehensive field observations of thunderstorms in the Beijing metropolitan regio...The Dynamical-microphysical-electrical Processes in Severe Thunderstorms and Lightning Hazards(STORM973)project conducted coordinated comprehensive field observations of thunderstorms in the Beijing metropolitan region(BMR)during the warm season from 2014 to 2018.The aim of the project was to understand how dynamical,microphysical and electrical processes interact in severe thunderstorms in the BMR,and how to assimilate lightning data in numerical weather prediction models to improve severe thunderstorm forecasts.The platforms used in the field campaign included the Beijing Lightning Network(BLNET,consisting of 16 stations),2 X-band dual linear polarimetric Doppler radars,and 4 laser raindrop spectrometers.The collaboration also made use of the China Meteorological Administration’s mesoscale meteorological observation network in the Beijing-Tianjin-Hebei region.Although diverse thunderstorm types were documented,it was found that squall lines and multicell storms were the two major categories of severe thunderstorms with frequent lightning activity and extreme rainfall or unexpected local short-duration heavy rainfall resulting in inundations in the central urban area,influenced by the terrain and environmental conditions.The flash density maximums were found in eastern Changping District,central and eastern Shunyi District,and the central urban area of Beijing,suggesting that the urban heat island effect has a crucial role in the intensification of thunderstorms over Beijing.In addition,the flash rate associated with super thunderstorms can reach hundreds of flashes per minute in the central city regions.The super(5%of the total),strong(35%),and weak(60%)thunderstorms contributed about 37%,56%,and 7%to the total flashes in the BMR,respectively.Owing to the close connection between lightning activity and the thermodynamic and microphysical characteristics of the thunderstorms,the lightning flash rate can be used as an indicator of severe weather events,such as hail and short-duration heavy rainfall.Lightning data can also be assimilated into numerical weather prediction models to help improve the forecasting of severe convection and precipitation at the cloud-resolved scale,through adjusting or correcting the thermodynamic and microphysical parameters of the model.展开更多
Artificial photosynthesis uses a catalyst to convert CO2 into valuable hydrocarbon products by cleaving the C--O bond. However, this technology is strongly limited by two issues, namely insufficient catalytic efficien...Artificial photosynthesis uses a catalyst to convert CO2 into valuable hydrocarbon products by cleaving the C--O bond. However, this technology is strongly limited by two issues, namely insufficient catalytic efficiency and complicated catalyst-fabrication processes. Herein, we report the development of a novel spray-drying photocatalyst-engineering process that addresses these two issues. Through one-step spray drying, with a residence time of 1.5 s, nanocomposites composed of tin oxide （SnO2） nanoparticles and edge-oxidized graphene oxide （eo-GO） sheets were fabricated without post-treatment. These nanocomposites exhibited 28-fold and five-fold enhancements in photocatalytic efficiency during CO2 reduction compared to SnO2 and commercialized TiO2 （P25）, respectively, after irradiation with simulated sunlight for 4 h. This scalable approach, based on short residence times and facile equipment setup, promotes the practical application of artificial photosynthesis through the potential mass production of efficient photocatalysts.展开更多
OBJECTIVE:To explore factors influencing the curative effect of scraping therapies (at acupoints or along channels) and to determine the relationship of scraping site and strength to curative effect. METHODS: Two hund...OBJECTIVE:To explore factors influencing the curative effect of scraping therapies (at acupoints or along channels) and to determine the relationship of scraping site and strength to curative effect. METHODS: Two hundred and ten patients with lumbar muscle strain were divided into five groups with 42 patients each.The "scraping therapy at acupoint until appearance of skin eruptions" and "scraping therapy along channel until appearance of skin eruptions" groups were treated with a 4-daycourse. The "scraping therapy at acupoint without appearance of skin eruptions", "scraping therapy along channel without appearance of skin eruptions", and acupuncture groups were treated with a 2-day course.The five groups were treated with seven courses. The visual analog scale (VAS), oswestry disability index (ODI), and lumbago scores were recorded in the five groups before treatment, after each treatment, and in follow-up visits one month and three months after treatment. RESULTS: VAS, ODI, and lumbago scores after treatment improved in the five groups (P<0.01). There was a statistical difference (P<0.01) in the change of VAS scores by appearance of skin eruptions and scraping site. CONCLUSION: Scraping therapy can effectively alleviate lumbago symptoms. The appearance of skin eruptions and scraping therapy along channels can enhance the curative effect of scraping therapy.展开更多
Lyme disease(LD)is a tick-transmitted infection caused by Borrelia burgdorferi sensu lato species,which include B.burgdorferi,Borrelia afzelii and Borrelia garinii.The majority of patients with early LD can be cured b...Lyme disease(LD)is a tick-transmitted infection caused by Borrelia burgdorferi sensu lato species,which include B.burgdorferi,Borrelia afzelii and Borrelia garinii.The majority of patients with early LD can be cured by the standard treatment,yet some still suffer from posttreatment LD syndrome.The presence of Borrelia persisters has been proposed as a contributing factor,because they cannot be completely eradicated by the currently used antibiotics for LD.Finding new pharmaceuticals targeting Borrelia persisters is crucial for developing more effective treatments.Here,we first confirmed the existence of persisters in B.garinii and B.afzelii cultures and then conducted a high-throughput screening of a customdrug library against persister-rich stationary-phase B.garinii and B.afzelii cultures.Among 2427 compounds screened,hypocrellin A(HA),anthracycline class of drugs and topical antibiotics along with some other natural compounds were identified to have strong potential for killing persisters of B.garinii and B.afzelii.HA was the most active anti-Borrelia compound,capable of eradicating stationary-phase Borrelia persisters,in particular when combined with doxycycline and/or ceftriaxone.Liposoluble antioxidant vitamin E was found to antagonize the activity of HA,indicating HA’s target is the cell membrane where HA triggers the generation of reactive oxygen species in the presence of light.HA was found to have distinct bactericidal activity against Borrelia species but had poor or no activity against gram-positive and gram-negative bacteria.Identification of the abovementioned drug candidates may help develop more effective therapies for LD.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.41875007 and 41630425)the Special Fund for Meteorology-Scientific Research in the Public Interest(Grant No.GYHY201506004)the 2018 Open Research Program of the State Key Laboratory of Severe Weather(Grant No.2018LASWB06)。
文摘Electrical characteristics of an isolated supercell storm observed on 13 June 2014 over Beijing were investigated using lightning data obtained from the Beijing Lightning Network,radar reflectivity,and hydrometeor retrievals during the 6-h lifetime.Positive cloud-to-ground(+CG)lightning took a high percentage of CG lightning.Before and during a hail event,+CG lightning was more frequent than negative cloud-to-ground(-CG)lightning,except that+CG lightning took a high percentage at the beginning and in the dissipating stage.After the hail event ended,-CG lightning dominated and reached its maximum value.An analysis of hydrometeors retrieved by X-band polarimetric radar revealed that the discharge concentrated in the convective region with graupel particles and hailstones,whereas graupel,snow and ice crystals in the stratiform region.Lightning radiation sources were located mainly in the convective region,some of which were distributed along a gradient of radar reflectivity from the convective region to the stratiform region.The indication is that the supercell demonstrated an inverted tripole charge structure before the hail event,which converted to a normal tripole structure after the hail event.
基金The National Natural Science Foundation of China(Grant Nos.41630425,41761144074 and 41875007)supported the researchthe Chinese Academy of Sciences for the CAS-PIFI fellowship grant。
文摘A thunderstorm tracking algorithm is proposed to nowcast the possibility of lightning activity over an area of concern by using the total lightning data and neighborhood technique.The lightning radiation sources observed from the Beijing Lightning Network(BLNET)were used to obtain information about the thunderstorm cells,which are significantly valuable in real-time.The boundaries of thunderstorm cells were obtained through the neighborhood technique.After smoothing,these boundaries were used to track the movement of thunderstorms and then extrapolated to nowcast the lightning approaching in an area of concern.The algorithm can deliver creditable results prior to a thunderstorm arriving at the area of concern,with accuracies of 63%,80%,and 91%for lead times of 30,15,and 5 minutes,respectively.The real-time observations of total lightning appear to be significant for thunderstorm tracking and lightning nowcasting,as total lightning tracking could help to fill the observational gaps in radar reflectivity due to the attenuation by hills or other obstacles.The lightning data used in the algorithm performs well in tracking the active thunderstorm cells associated with lightning activities.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFC1501500).
文摘Atmospheric electricity is composed of a series of electric phenomena in the atmosphere.Significant advances in atmospheric electricity research conducted in China have been achieved in recent years.In this paper,the research progress on atmospheric electricity achieved in China during 2019-22 is reviewed focusing on the following aspects:(1)lightning detection and location techniques,(2)thunderstorm electricity,(3)lightning forecasting methods and techniques,(4)physical processes of lightning discharge,(5)high energy emissions and effects of thunderstorms on the upper atmosphere,and(6)the effect of aerosol on lightning.
基金support from the National Science Foundation(NSF-CBET-1264599 and 1351384)support of the Maryland NanoCenter and its NispLab+1 种基金supported in part by the NSF as a MRSEC Shared Experimental Facilitythe China Scholarship Council (CSC) (No. 201306150076) for a fellowship to support his study at the University of Maryland
文摘Platinum and zinc containing LTA zeolite catalysts with tunable meso/microporosity were prepared by using ligand-metal precursors under hydrothermal condition. These materials were employed for oxidation of ethane to oxygenates using hydrogen peroxides as oxidant under mild reaction condition. The results showed that platinum and zinc loaded LTA zeolites were effective for the partial oxidation of ethane with hydrogen peroxide giving the desired C_2 oxygenates. Moreover, the C_1 oxygenates were also obtained through subsequent C–C bond scission pathways. The over oxidation of ethanol/methanol to acetic acid/formic acid could be inhibited through the introduction of mesoporosity in LTA zeolites. Our findings for oxidation of ethane suggested that the selectivity to the oxidation products such as alcohols and acids could be tailored by tuning the metal species within the LTA zeolites and porosity of catalysts, indicating that a balance between the meso/microporosity and metal species in LTA zeolites can be realized for desirable catalysis by one-pot synthesis of zeolites. In addition, the selectivity to oxygenates can also be tuned by control of the reaction conditions, i.e. concentration of hydrogen peroxide or reaction time.
基金supported by the National Natural Science Foundation of China(Grant Nos.41630425,41671144074)the Key Research Program of Frontier Science,CAS(Grant No.QYZDJ-SSW-DQC007)the National Key Basic Research Program of China(Grant No.2014CB441401)。
文摘The Dynamical-microphysical-electrical Processes in Severe Thunderstorms and Lightning Hazards(STORM973)project conducted coordinated comprehensive field observations of thunderstorms in the Beijing metropolitan region(BMR)during the warm season from 2014 to 2018.The aim of the project was to understand how dynamical,microphysical and electrical processes interact in severe thunderstorms in the BMR,and how to assimilate lightning data in numerical weather prediction models to improve severe thunderstorm forecasts.The platforms used in the field campaign included the Beijing Lightning Network(BLNET,consisting of 16 stations),2 X-band dual linear polarimetric Doppler radars,and 4 laser raindrop spectrometers.The collaboration also made use of the China Meteorological Administration’s mesoscale meteorological observation network in the Beijing-Tianjin-Hebei region.Although diverse thunderstorm types were documented,it was found that squall lines and multicell storms were the two major categories of severe thunderstorms with frequent lightning activity and extreme rainfall or unexpected local short-duration heavy rainfall resulting in inundations in the central urban area,influenced by the terrain and environmental conditions.The flash density maximums were found in eastern Changping District,central and eastern Shunyi District,and the central urban area of Beijing,suggesting that the urban heat island effect has a crucial role in the intensification of thunderstorms over Beijing.In addition,the flash rate associated with super thunderstorms can reach hundreds of flashes per minute in the central city regions.The super(5%of the total),strong(35%),and weak(60%)thunderstorms contributed about 37%,56%,and 7%to the total flashes in the BMR,respectively.Owing to the close connection between lightning activity and the thermodynamic and microphysical characteristics of the thunderstorms,the lightning flash rate can be used as an indicator of severe weather events,such as hail and short-duration heavy rainfall.Lightning data can also be assimilated into numerical weather prediction models to help improve the forecasting of severe convection and precipitation at the cloud-resolved scale,through adjusting or correcting the thermodynamic and microphysical parameters of the model.
文摘Artificial photosynthesis uses a catalyst to convert CO2 into valuable hydrocarbon products by cleaving the C--O bond. However, this technology is strongly limited by two issues, namely insufficient catalytic efficiency and complicated catalyst-fabrication processes. Herein, we report the development of a novel spray-drying photocatalyst-engineering process that addresses these two issues. Through one-step spray drying, with a residence time of 1.5 s, nanocomposites composed of tin oxide （SnO2） nanoparticles and edge-oxidized graphene oxide （eo-GO） sheets were fabricated without post-treatment. These nanocomposites exhibited 28-fold and five-fold enhancements in photocatalytic efficiency during CO2 reduction compared to SnO2 and commercialized TiO2 （P25）, respectively, after irradiation with simulated sunlight for 4 h. This scalable approach, based on short residence times and facile equipment setup, promotes the practical application of artificial photosynthesis through the potential mass production of efficient photocatalysts.
基金Supported by National Sci-tech Project in "the 11th Five-year Plan": Standardized Research into Treatment of Lumbago with Reinforcing and Reducing Methods of Scraping Therapy(2008 BAI53B063)National Natural Science Foundation Project: Research into Biological Effect and Mechanism of Scraping Manipulations(81173346)
文摘OBJECTIVE:To explore factors influencing the curative effect of scraping therapies (at acupoints or along channels) and to determine the relationship of scraping site and strength to curative effect. METHODS: Two hundred and ten patients with lumbar muscle strain were divided into five groups with 42 patients each.The "scraping therapy at acupoint until appearance of skin eruptions" and "scraping therapy along channel until appearance of skin eruptions" groups were treated with a 4-daycourse. The "scraping therapy at acupoint without appearance of skin eruptions", "scraping therapy along channel without appearance of skin eruptions", and acupuncture groups were treated with a 2-day course.The five groups were treated with seven courses. The visual analog scale (VAS), oswestry disability index (ODI), and lumbago scores were recorded in the five groups before treatment, after each treatment, and in follow-up visits one month and three months after treatment. RESULTS: VAS, ODI, and lumbago scores after treatment improved in the five groups (P<0.01). There was a statistical difference (P<0.01) in the change of VAS scores by appearance of skin eruptions and scraping site. CONCLUSION: Scraping therapy can effectively alleviate lumbago symptoms. The appearance of skin eruptions and scraping therapy along channels can enhance the curative effect of scraping therapy.
基金the National Natural Science Foundation of China(no.81902099)the State Key Laboratory of Veterinary Etiological Biology,Lanzhou Veterinary Research Institute,Chinese Academy of Agricultural Sciences(no.SKLVEB2020KFKT005).
文摘Lyme disease(LD)is a tick-transmitted infection caused by Borrelia burgdorferi sensu lato species,which include B.burgdorferi,Borrelia afzelii and Borrelia garinii.The majority of patients with early LD can be cured by the standard treatment,yet some still suffer from posttreatment LD syndrome.The presence of Borrelia persisters has been proposed as a contributing factor,because they cannot be completely eradicated by the currently used antibiotics for LD.Finding new pharmaceuticals targeting Borrelia persisters is crucial for developing more effective treatments.Here,we first confirmed the existence of persisters in B.garinii and B.afzelii cultures and then conducted a high-throughput screening of a customdrug library against persister-rich stationary-phase B.garinii and B.afzelii cultures.Among 2427 compounds screened,hypocrellin A(HA),anthracycline class of drugs and topical antibiotics along with some other natural compounds were identified to have strong potential for killing persisters of B.garinii and B.afzelii.HA was the most active anti-Borrelia compound,capable of eradicating stationary-phase Borrelia persisters,in particular when combined with doxycycline and/or ceftriaxone.Liposoluble antioxidant vitamin E was found to antagonize the activity of HA,indicating HA’s target is the cell membrane where HA triggers the generation of reactive oxygen species in the presence of light.HA was found to have distinct bactericidal activity against Borrelia species but had poor or no activity against gram-positive and gram-negative bacteria.Identification of the abovementioned drug candidates may help develop more effective therapies for LD.
