The demand and pursuit of chemical entities with UV filtration and antioxidant properties for enhanced photoprotection have been driven in recent times by acute exposure of humans to solar ultraviolet radiations. The ...The demand and pursuit of chemical entities with UV filtration and antioxidant properties for enhanced photoprotection have been driven in recent times by acute exposure of humans to solar ultraviolet radiations. The structural, electronic, antioxidant and UV absorption properties of drometrizole (PBT) and designed ortho-substituted derivatives are reported via DFT and TD-DFT in the gas and aqueous phases. DFT and TD-DFT computations were performed at the M062x-D3Zero/6-311++G(d,p)//B97-3c and PBE0-D3(BJ)/def2-TZVP levels of theory respectively. Reaction enthalpies related to hydrogen atom transfer (HAT), single-electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET) mechanisms were computed and compared with those of phenol. Results show that the presence of -NH2 substituent reduces the O-H bond dissociation enthalpy and ionization potential, while that of -CN increases the proton affinity. The HAT and SPLET mechanisms are the most plausible in the gas and aqueous phases respectively. The molecule with the -NH2 substituent (PBT1) was identified to be the compound with the highest antioxidant activity. The UV spectra of the studied compounds are characterized by two bands in the 280 - 400 nm regions. Results from this study provide a better comprehension antioxidant mechanism of drometrizole and present a new perspective for the design of electron-donor antioxidant molecules with enhanced antioxidant-photoprotective efficiencies for applications in commercial sunscreens.展开更多
Electrochemical cell can overcome the inherent intermittence of the renewable energy sources,thus showing great potentials in applications ranging from elec-trical energy storage to future smart grid.However,the curre...Electrochemical cell can overcome the inherent intermittence of the renewable energy sources,thus showing great potentials in applications ranging from elec-trical energy storage to future smart grid.However,the current electrochemical cells could not achieve the“total green”feature by fully utilizing the clean and abundant O_(2)/H_(2)O redox couples due to the enormous overpotentials for both oxygen reduction reaction(ORR)and oxygen release reaction(OER).Herein,we report a“total green”electrochemical composite film cell based on carbon dots(CDots),which can realize both ORR and OER in the acid environment.The in-air voltage generation(0.95 V,with a maximum power of 5.3μW)relies on the multiple-electron-transfer redox chemical reaction between the two active components inside the composite film,that is,ORR/OER of CDots and the redox reaction of polyaniline(PANI)on the electrode and the resulting proton concentration gradient.Interestingly,the cell can be self-recovered at low load,recharged by adding H_(2)O_(2),or electrocharged at high load.We anticipate that current study may open up new opportunities for designing and developing total-green energy storage and conversion systems for diverse applications.展开更多
We analyze the line data from solar flares to present evidence for the emission spectrum of the recently discussed electron-proton pairs at high temperatures. We also point out that since the pairing phenomenon provid...We analyze the line data from solar flares to present evidence for the emission spectrum of the recently discussed electron-proton pairs at high temperatures. We also point out that since the pairing phenomenon provides an additional source for these lines—the conventional source being the highly ionized high-Z atoms already existing in the solar atmosphere, we have a plausible explanation of the FIP effect.展开更多
The results of two-boson-exchange effects in the parity-violating elastic electron-proton scattering are reported based on a simple hadronic model. The corrections are calculated including the nucleon and △（1232） i...The results of two-boson-exchange effects in the parity-violating elastic electron-proton scattering are reported based on a simple hadronic model. The corrections are calculated including the nucleon and △（1232） intermediate states. And the numerical results are also compared with the recent results reported by other group and other methods.展开更多
Background The electromagnetic calorimeter(ECAL)of the Alpha Magnetic Spectrometer(AMS-02)measures the energy of electrons/positrons and separates them from protons.Currently,there are five dead cells in the ECAL whic...Background The electromagnetic calorimeter(ECAL)of the Alpha Magnetic Spectrometer(AMS-02)measures the energy of electrons/positrons and separates them from protons.Currently,there are five dead cells in the ECAL which affect the reconstructed energy of particles.The particle identification power of the ECAL decreases when particles pass through these dead cells or close to the ECAL border.Purpose To improve the ECAL particle identification for particles pass through these dead cells or close to the ECAL border.Methods An improved ECAL particle identification estimator using the electromagnetic shower shape is developed with dead cell and side leakage corrections.Results For events passing through dead cells,with this new estimator,the proton rejection power is improved by a factor of 2.2 and positron purity is improved from 31 to 50%in the energy range of 500–800 GeV.Conclusion The new estimator works well for event passing through dead cells or close to the ECAL border.展开更多
Electro-production of several pentaquark states is investigated in this study.The eSTARlight package is adapted to study the electro-production of J/ψand γ(1S)via pentaquark P_(c)and P_(b)resonance channels in ep→...Electro-production of several pentaquark states is investigated in this study.The eSTARlight package is adapted to study the electro-production of J/ψand γ(1S)via pentaquark P_(c)and P_(b)resonance channels in ep→eJ/ψp and ep→eγ(1S)p scattering processes at the proposed electron-ion colliders(EICs).The results obtained in this study are compared to those of non-resonance t-channels,which are described in the pomeron exchange model developed in our studies.Some pseudo-rapidity and rapidity distributions of J/ψand γ(1S)are presented for the proposed EICs,including EicC and EIC-US.It is found that EicC is a good platform to identify P_(b) states in the future.展开更多
文摘The demand and pursuit of chemical entities with UV filtration and antioxidant properties for enhanced photoprotection have been driven in recent times by acute exposure of humans to solar ultraviolet radiations. The structural, electronic, antioxidant and UV absorption properties of drometrizole (PBT) and designed ortho-substituted derivatives are reported via DFT and TD-DFT in the gas and aqueous phases. DFT and TD-DFT computations were performed at the M062x-D3Zero/6-311++G(d,p)//B97-3c and PBE0-D3(BJ)/def2-TZVP levels of theory respectively. Reaction enthalpies related to hydrogen atom transfer (HAT), single-electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET) mechanisms were computed and compared with those of phenol. Results show that the presence of -NH2 substituent reduces the O-H bond dissociation enthalpy and ionization potential, while that of -CN increases the proton affinity. The HAT and SPLET mechanisms are the most plausible in the gas and aqueous phases respectively. The molecule with the -NH2 substituent (PBT1) was identified to be the compound with the highest antioxidant activity. The UV spectra of the studied compounds are characterized by two bands in the 280 - 400 nm regions. Results from this study provide a better comprehension antioxidant mechanism of drometrizole and present a new perspective for the design of electron-donor antioxidant molecules with enhanced antioxidant-photoprotective efficiencies for applications in commercial sunscreens.
基金National Key Research and Development Program of China,Grant/Award Num-bers:2018YFE0306105,2020YFA0406104,2020YFA0406101National Natural Sci-ence Foundation of China,Grant/Award Numbers:21574094,51821002,51725204,21771132,51972216,52041202+4 种基金Natural Sci-ence Foundation of Jiangsu Province,Grant/Award Number:BK20190041Col-laborative Innovation Center of Suzhou Nano Science&Technology111 Project,Joint International Research Laboratory of Carbon-Based Functional Materials and Devicesthe Fund for Excellent Creative Research Teams of Jiangsu Higher Educa-tion InstitutionsJiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Soochow University。
文摘Electrochemical cell can overcome the inherent intermittence of the renewable energy sources,thus showing great potentials in applications ranging from elec-trical energy storage to future smart grid.However,the current electrochemical cells could not achieve the“total green”feature by fully utilizing the clean and abundant O_(2)/H_(2)O redox couples due to the enormous overpotentials for both oxygen reduction reaction(ORR)and oxygen release reaction(OER).Herein,we report a“total green”electrochemical composite film cell based on carbon dots(CDots),which can realize both ORR and OER in the acid environment.The in-air voltage generation(0.95 V,with a maximum power of 5.3μW)relies on the multiple-electron-transfer redox chemical reaction between the two active components inside the composite film,that is,ORR/OER of CDots and the redox reaction of polyaniline(PANI)on the electrode and the resulting proton concentration gradient.Interestingly,the cell can be self-recovered at low load,recharged by adding H_(2)O_(2),or electrocharged at high load.We anticipate that current study may open up new opportunities for designing and developing total-green energy storage and conversion systems for diverse applications.
文摘We analyze the line data from solar flares to present evidence for the emission spectrum of the recently discussed electron-proton pairs at high temperatures. We also point out that since the pairing phenomenon provides an additional source for these lines—the conventional source being the highly ionized high-Z atoms already existing in the solar atmosphere, we have a plausible explanation of the FIP effect.
基金Supported by National Natural Science Foundation of China (10805009)
文摘The results of two-boson-exchange effects in the parity-violating elastic electron-proton scattering are reported based on a simple hadronic model. The corrections are calculated including the nucleon and △（1232） intermediate states. And the numerical results are also compared with the recent results reported by other group and other methods.
文摘Background The electromagnetic calorimeter(ECAL)of the Alpha Magnetic Spectrometer(AMS-02)measures the energy of electrons/positrons and separates them from protons.Currently,there are five dead cells in the ECAL which affect the reconstructed energy of particles.The particle identification power of the ECAL decreases when particles pass through these dead cells or close to the ECAL border.Purpose To improve the ECAL particle identification for particles pass through these dead cells or close to the ECAL border.Methods An improved ECAL particle identification estimator using the electromagnetic shower shape is developed with dead cell and side leakage corrections.Results For events passing through dead cells,with this new estimator,the proton rejection power is improved by a factor of 2.2 and positron purity is improved from 31 to 50%in the energy range of 500–800 GeV.Conclusion The new estimator works well for event passing through dead cells or close to the ECAL border.
基金National Natural Science Foundation of China(11975278,11405222)Key Research Program of the Chinese Academy of Sciences(XDPB09)。
文摘Electro-production of several pentaquark states is investigated in this study.The eSTARlight package is adapted to study the electro-production of J/ψand γ(1S)via pentaquark P_(c)and P_(b)resonance channels in ep→eJ/ψp and ep→eγ(1S)p scattering processes at the proposed electron-ion colliders(EICs).The results obtained in this study are compared to those of non-resonance t-channels,which are described in the pomeron exchange model developed in our studies.Some pseudo-rapidity and rapidity distributions of J/ψand γ(1S)are presented for the proposed EICs,including EicC and EIC-US.It is found that EicC is a good platform to identify P_(b) states in the future.
