Time evolution of ionospheric D-region plasmas including the perturbations of electrons and charged aerosol particles is investigated under the conditions of polar mesosphere summer echoes （PMSE）. It is shown that t...Time evolution of ionospheric D-region plasmas including the perturbations of electrons and charged aerosol particles is investigated under the conditions of polar mesosphere summer echoes （PMSE）. It is shown that the time scale of decay of the electron density is in the order of an hour under typical PMSE conditions, in the majority of cases, the electron density is anticorrelated to the ion density, except that the radius of aerosol particles is greater than 50 nm. Also, the evolutions under varied parameters, such as the amplitude and width of perturbation, the aerosol particle radius, and the altitude of the PMSE occurrence are investigated. The obtained results are useful for interpreting the experimental observations.展开更多
Interactions between water and solid substrates are of fundamental importance to various processes in nature and industry.Electric control is widely used to modify interfacial water,where the influence of surface char...Interactions between water and solid substrates are of fundamental importance to various processes in nature and industry.Electric control is widely used to modify interfacial water,where the influence of surface charges is inevitable.Here we obtain positively and negatively charged surfaces using Li Ta O_(3) crystals and observe that a large net surface charge up to 0.1 C/m;can nominally change the contact angles of pure water droplets comparing to the same uncharged surface.However,even a small amount of surface charge can efficiently increase the water contact angle in the presence of aerosols.Our results indicate that such surface charges can hardly affect the structure of interfacial water molecular layers and the morphology of the macroscopic droplet,while adsorption of a small amount of organic contaminants from aerosols with the help of Coulomb attraction can notably decrease the wettability of solid surface.Our results not only provide a fundamental understanding of the interactions between charged surfaces and water,but also help to develop new techniques on electric control of wettability and microfluidics in real aerosol environments.展开更多
The corona discharges provide an efficient way to induce precipitation or eliminate fog by increasing ion density in the open air.In this paper,one bipolar corona discharge array(positive and negative high voltage cou...The corona discharges provide an efficient way to induce precipitation or eliminate fog by increasing ion density in the open air.In this paper,one bipolar corona discharge array(positive and negative high voltage coupled simultaneously)which can generate high densities of positive and negative ions is developed.The comparison between bipolar corona discharge array and unipolar corona discharge array(positive or negative coupled only)indicates that bipolar corona discharge array can generate~3 times higher ion density than unipolar corona discharge array.More charged aerosols are produced through collisions between ions and aerosols.The collision rate between aerosols is increased substantially by the attractive forces between positively and negatively charged aerosols.The deposition of aerosols induced by bipolar discharges is 25.7%higher than that of unipolar discharges at the humidity super-saturation condition.Therefore,the bipolar corona discharge system is a new option for the large scale ion sources used for artificial weather modification.展开更多
酸枣仁为鼠李科植物酸枣Ziziphus jujuba Mill.var.spinosa(Bunge)Hu ex H.F.Chou的干燥成熟种子,其分为种皮、种仁两个部位,比较研究酸枣仁不同部位化学成分组成及相对含量可为合理开发利用中药酸枣仁资源提供理论依据。基于超高效液...酸枣仁为鼠李科植物酸枣Ziziphus jujuba Mill.var.spinosa(Bunge)Hu ex H.F.Chou的干燥成熟种子,其分为种皮、种仁两个部位,比较研究酸枣仁不同部位化学成分组成及相对含量可为合理开发利用中药酸枣仁资源提供理论依据。基于超高效液相色谱-四极杆飞行时间质谱(UPLC-Q-TOF/MS)技术,从种皮、种仁中共鉴定出57个化学成分。结合主成分分析(PCA)和正交偏最小二乘法判别分析(OPLS-DA)对两者进行差异成分研究,以变量投影重要度(VIP)值>5为标准,筛选了差异成分17个,其中白桦脂酸、桦木酮酸、麦珠子酸和酸枣仁皂苷Ⅰ主要存在于种皮部位,斯皮诺素、酸枣仁皂苷A和6-阿魏酰斯皮诺素等13个化合物主要存在于种仁部位。通过超高效液相色谱-电雾式检测器(UPLC-CAD)结合反梯度补偿技术,建立半定量液相色谱指纹图谱,考察了6个不同结构类型的代表成分的响应一致性,其不同浓度下平均响应因子间的RSD值为7.04%,各化合物响应一致性良好,可用于酸枣仁的半定量表征分析;结果表明:种皮部位主要成分为白桦脂酸和油酸,其中白桦脂酸的含量约是种仁的7倍;种仁部位主要成分为斯皮诺素、酸枣仁皂苷A、亚油酸、白桦脂酸和油酸,其中斯皮诺素、酸枣仁皂苷A的含量分别是种皮的18倍和24倍。综上,本研究阐明了酸枣仁种皮、种仁的化学成分差异,明确了酸枣仁两个部位中各自的主要成分及其相对含量,为酸枣仁不同部位合理开发和利用奠定了基础。展开更多
基金supported by National Natural Science Foundation of China (Nos. 40831062, 10775134)partially supported by CAS Knowledge Innovation Program (No. kjcx2-yw-n28)National Basic Research Program of China (Nos. 2008CB717800, 2009GB105001)
文摘Time evolution of ionospheric D-region plasmas including the perturbations of electrons and charged aerosol particles is investigated under the conditions of polar mesosphere summer echoes （PMSE）. It is shown that the time scale of decay of the electron density is in the order of an hour under typical PMSE conditions, in the majority of cases, the electron density is anticorrelated to the ion density, except that the radius of aerosol particles is greater than 50 nm. Also, the evolutions under varied parameters, such as the amplitude and width of perturbation, the aerosol particle radius, and the altitude of the PMSE occurrence are investigated. The obtained results are useful for interpreting the experimental observations.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12025407,11934003,9185012011774328)+1 种基金the Key R&D Program of China(Grant No.2016YFA0300902)the Chinese Academy of Sciences。
文摘Interactions between water and solid substrates are of fundamental importance to various processes in nature and industry.Electric control is widely used to modify interfacial water,where the influence of surface charges is inevitable.Here we obtain positively and negatively charged surfaces using Li Ta O_(3) crystals and observe that a large net surface charge up to 0.1 C/m;can nominally change the contact angles of pure water droplets comparing to the same uncharged surface.However,even a small amount of surface charge can efficiently increase the water contact angle in the presence of aerosols.Our results indicate that such surface charges can hardly affect the structure of interfacial water molecular layers and the morphology of the macroscopic droplet,while adsorption of a small amount of organic contaminants from aerosols with the help of Coulomb attraction can notably decrease the wettability of solid surface.Our results not only provide a fundamental understanding of the interactions between charged surfaces and water,but also help to develop new techniques on electric control of wettability and microfluidics in real aerosol environments.
基金supported by National Key Research and Development Plan of China(No.2016YFC0401001)。
文摘The corona discharges provide an efficient way to induce precipitation or eliminate fog by increasing ion density in the open air.In this paper,one bipolar corona discharge array(positive and negative high voltage coupled simultaneously)which can generate high densities of positive and negative ions is developed.The comparison between bipolar corona discharge array and unipolar corona discharge array(positive or negative coupled only)indicates that bipolar corona discharge array can generate~3 times higher ion density than unipolar corona discharge array.More charged aerosols are produced through collisions between ions and aerosols.The collision rate between aerosols is increased substantially by the attractive forces between positively and negatively charged aerosols.The deposition of aerosols induced by bipolar discharges is 25.7%higher than that of unipolar discharges at the humidity super-saturation condition.Therefore,the bipolar corona discharge system is a new option for the large scale ion sources used for artificial weather modification.
文摘酸枣仁为鼠李科植物酸枣Ziziphus jujuba Mill.var.spinosa(Bunge)Hu ex H.F.Chou的干燥成熟种子,其分为种皮、种仁两个部位,比较研究酸枣仁不同部位化学成分组成及相对含量可为合理开发利用中药酸枣仁资源提供理论依据。基于超高效液相色谱-四极杆飞行时间质谱(UPLC-Q-TOF/MS)技术,从种皮、种仁中共鉴定出57个化学成分。结合主成分分析(PCA)和正交偏最小二乘法判别分析(OPLS-DA)对两者进行差异成分研究,以变量投影重要度(VIP)值>5为标准,筛选了差异成分17个,其中白桦脂酸、桦木酮酸、麦珠子酸和酸枣仁皂苷Ⅰ主要存在于种皮部位,斯皮诺素、酸枣仁皂苷A和6-阿魏酰斯皮诺素等13个化合物主要存在于种仁部位。通过超高效液相色谱-电雾式检测器(UPLC-CAD)结合反梯度补偿技术,建立半定量液相色谱指纹图谱,考察了6个不同结构类型的代表成分的响应一致性,其不同浓度下平均响应因子间的RSD值为7.04%,各化合物响应一致性良好,可用于酸枣仁的半定量表征分析;结果表明:种皮部位主要成分为白桦脂酸和油酸,其中白桦脂酸的含量约是种仁的7倍;种仁部位主要成分为斯皮诺素、酸枣仁皂苷A、亚油酸、白桦脂酸和油酸,其中斯皮诺素、酸枣仁皂苷A的含量分别是种皮的18倍和24倍。综上,本研究阐明了酸枣仁种皮、种仁的化学成分差异,明确了酸枣仁两个部位中各自的主要成分及其相对含量,为酸枣仁不同部位合理开发和利用奠定了基础。
