Impact of the Vertical Velocity Field on Charging Processes and Charge Separation in a Simulated Thunderstorm

A three-dimensional（3D） charging-discharging cloud resolution model was used to investigate the impact of the vertical velocity field on the charging processes and the formation of charge structure in a strong thunderstorm. The distribution and evolution of ice particle content and charges on ice particles were analyzed in different vertical velocity fields. The results show that the ice particles in the vertical velocity range from 1 to 5 m s-1obtained the most charge through charging processes during the lifetime of the thunderstorm. The magnitude of the charges could reach 1014 n C. Before the beginning of lightning activity,the charges produced in updraft region 2（updraft speed 13 m s-1） and updraft region 1（updraft speed between 5 and 13 m s-1） were relatively significant. The magnitudes of charge reached 1013 n C, which clearly impacted upon the early lightning activity. The vertical velocity conditions in the quasi-steady region（updraft speed between -1 and 1 m s-1） were the most conducive for charge separation on ice particles on different scales. Accordingly, a net charge structure always appeared in the quasi-steady and adjacent regions. Based on the results, a conceptual model of ice particle charging, charge separation, and charge structure formation in the flow field was constructed. The model helps to explain observations of the＂lightning hole＂ phenomenon.

Defining an open access resource strategy for research libraries:Part Ⅱ——Challenges and responses

Purpose: This paper aims to provide a systematic analysis of challenges and responses of the imminent open access-based environment so as to enable sound development of open access(OA) resource strategies.Design/methodology/approach: A systematic and evidence-based analysis is used to discover, identify, and contextualize the factors that relate or interact. A challenge metric for the overall context and additional frameworks or alternative lists is used for the detailed analysis.Findings: Research libraries are facing a reality conflict between the traditional library solution and the OA solution. New resource strategies are needed but have to be based on an open knowledge infrastructure and a systematic analysis of factors and alternatives. Support for OA publishing is becoming a major task and complicated capabilities involved call for libraries to play a central role. Hybrid collection development should be in place to take full advantages of the open world while ensuring reliable and trusted retrieval, reuse, and preservation.Research limitations: The research covers main developments in US and European countries mostly in scientific fields and for scholarly papers.Practical implications: There are already evidences for sound OA resource policies. With the imminent dominance of OA resources, research libraries should and can set up their OA resource strategies.Originality/value: The paper suggests a factor metric as an analysis framework, presents rationale lists and policies to support OA publishing, and proposes a hybrid collection strategy to plan for collection development, retrieval, and preservation.

Nonylphenol photodegradation by novel ternary MIL-100(Fe)/ZnFe_(2)O_(4)/PCN composite under visible light irradiation via double charge transfer process

Nonylphenol(NP)residues,as a typical endocrine disrupting chemical(EDC),frequently exist in sewage,surface water,groundwater and even drinking water,which poses a serious threat to human health due to its bioaccumulation.In order to remove NP,a series of MIL-100(Fe)/Zn Fe_(2)O_(4)/flake-like porous carbon nitride(MIL/ZC)was synthesized through in-situ synthesis at room temperature.High performance of ternary MIL/ZC is used to degrade NP under visible light irradiation.The results show that 30MIL/ZC2(20 wt.%Zn Fe_(2)O_(4))ternary composite had the best photocatalytic activity(99.84%)when the dosage was 30 mg.Further mechanism analysis shows that the excellent photocatalytic activity of 30MIL/ZC2could be ascribed to the double charge transfer process between flake-like porous carbon nitride(PCN)and other catalysts in the ternary heterojunction,and the separation of photogenerated electron-hole pairs was more effective.In addition,the 30MIL/ZC2 also showed high stability after five cycles of the photodegradation reaction.Furthermore,the active substance(·O_(2)^(-))was considered to be the main active substance in the NP degradation process.Based on the research results,the possible photocatalytic reaction mechanism of 30MIL/ZC2ternary composite was proposed and discussed in detail.

Co-doping method used to improve the charge transport balance in solution processed OLEDs

In this paper, co-doping method is used to improve the current efficiency of solution-processed organic light-emitting diodes(OLEDs). By changing the ratio of two thermally activated delayed fluorescent(TADF) emitters, we studied the performance of device and its mechanism. A solution processed OLED with a structure of indium tin oxide(ITO, 150 nm)/PEDOT:PSS(30 nm)/CBP:4 Cz IPN-x%:4 Cz PN-y%(30 nm)/TPBi(40 nm)/Li F(1 nm)/Al(100 nm) was fabricated. The current efficiencies of 26.6 cd/A and 26.4 cd/A were achieved by the devices with dopant ratio of 6% 4 Cz IPN:2% 4 Cz PN and 2% 4 Cz IPN:6% 4 Cz PN in emitting material layer(EML), respectively. By investigating the tendency of current density change in devices with different doping ratio, we suggested that the enhancement of the current efficiency should be due to the charge transport balance improvement induced by assist dopant in EML.

MODELING CHARGE RELAXATION ON SURFACES OF PARTICLES SUSPENDED IN LIQUID

A general theory on charges relaxation process in particle-fluid systems is introduced in this article. The method to derive analytical solutions for the charge relaxation equation is illustrated, and some respects for this theory are discussed in detail.