In this study,the authors focus on the cut-off low pressure systems（COLs）lingering over East Asia in late spring and early summer and quantify the two-way stratosphere–troposphere exchange（STE）by 3D trajectory in...In this study,the authors focus on the cut-off low pressure systems（COLs）lingering over East Asia in late spring and early summer and quantify the two-way stratosphere–troposphere exchange（STE）by 3D trajectory integrations,achieved using a revised version of the UK Universities Global Atmospheric Modelling Programme Offline Trajectory Code（Version 3）.By selecting 10 typical COLs and calculating the cross-tropopause air mass fluxes,it is found that stratosphere-to-troposphere transport（STT）fluxes exist in the center of COLs;and in the periphery of the COL center,troposphereto-stratosphere transport（TST）fluxes and STT fluxes are distributed alternately.Net transport fluxes in COLs are from stratosphere to troposphere,and the magnitude is about 10-4 kg m-2 s-1.The ratio between the area-averaged STT and TST fluxes increases with increasing strength of the COLs.By adopting appropriate residence time,the spurious transports are effectively excluded.Finally,the authors compare the results with previous studies,and find that the cross-tropopause fluxes（CTFs）induced by COLs are about one to two orders of magnitude larger than global CTFs.COLs play a significant role in local,rapid air mass exchanges,although they may only be responsible for a fraction of the total STE.展开更多
Organic thin film transistors(OTFTs)are normally sensitive to ambient conditions and show performance degradation in air.On the contrary,the performance of flexible 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene(C8...Organic thin film transistors(OTFTs)are normally sensitive to ambient conditions and show performance degradation in air.On the contrary,the performance of flexible 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene(C8-BTBT)OTFTs using cross-linked polymer layer,poly(4-vinyl-phenol)-4,4’-(hexafluoroisopropylidene)diphthalic anhydride(PVP-HDA),as the dielectric layer can be improved in air conditions with 40%relative humidity.Under soaking in air with 40%relative humidity,the electrical behavior,surface morphology,and contact angle of the flexible C8-BTBT OTFTs using PVP-HAD as dielectric layer with three different thicknesses were investigated.It is found that,when the devices with 375 nm-thick PVP-HDA films are placed in 40%relative humidity air conditions for 6 h,the corrected average mobility(μ)can increase from 3.2 to 5.1 cm^2 V^-1 s^-1.Furthermore,the average threshold voltage(Vth)changes from-12.4 to-9.3 V while keeping a constant ratio of I on/Ioff=10^4.These results indicate that the flexible C8-BTBT OTFTs with PVP-HDA dielectric layer exhibit interesting application prospects.展开更多
基金supported by the Special Fund for Strategic Pilot Technology,Chinese Academy of Sciences[grant number XDA05040300]
文摘In this study,the authors focus on the cut-off low pressure systems（COLs）lingering over East Asia in late spring and early summer and quantify the two-way stratosphere–troposphere exchange（STE）by 3D trajectory integrations,achieved using a revised version of the UK Universities Global Atmospheric Modelling Programme Offline Trajectory Code（Version 3）.By selecting 10 typical COLs and calculating the cross-tropopause air mass fluxes,it is found that stratosphere-to-troposphere transport（STT）fluxes exist in the center of COLs;and in the periphery of the COL center,troposphereto-stratosphere transport（TST）fluxes and STT fluxes are distributed alternately.Net transport fluxes in COLs are from stratosphere to troposphere,and the magnitude is about 10-4 kg m-2 s-1.The ratio between the area-averaged STT and TST fluxes increases with increasing strength of the COLs.By adopting appropriate residence time,the spurious transports are effectively excluded.Finally,the authors compare the results with previous studies,and find that the cross-tropopause fluxes（CTFs）induced by COLs are about one to two orders of magnitude larger than global CTFs.COLs play a significant role in local,rapid air mass exchanges,although they may only be responsible for a fraction of the total STE.
基金supported by the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51673214)。
文摘Organic thin film transistors(OTFTs)are normally sensitive to ambient conditions and show performance degradation in air.On the contrary,the performance of flexible 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene(C8-BTBT)OTFTs using cross-linked polymer layer,poly(4-vinyl-phenol)-4,4’-(hexafluoroisopropylidene)diphthalic anhydride(PVP-HDA),as the dielectric layer can be improved in air conditions with 40%relative humidity.Under soaking in air with 40%relative humidity,the electrical behavior,surface morphology,and contact angle of the flexible C8-BTBT OTFTs using PVP-HAD as dielectric layer with three different thicknesses were investigated.It is found that,when the devices with 375 nm-thick PVP-HDA films are placed in 40%relative humidity air conditions for 6 h,the corrected average mobility(μ)can increase from 3.2 to 5.1 cm^2 V^-1 s^-1.Furthermore,the average threshold voltage(Vth)changes from-12.4 to-9.3 V while keeping a constant ratio of I on/Ioff=10^4.These results indicate that the flexible C8-BTBT OTFTs with PVP-HDA dielectric layer exhibit interesting application prospects.
