PSⅡ photochemistry and xanthophyll cycle during photoinhibition (exposed to strong light of 2 000 μmol photons·m -2 ·s -1 ) and the subsequent restoration were compared between two superhigh_yi...PSⅡ photochemistry and xanthophyll cycle during photoinhibition (exposed to strong light of 2 000 μmol photons·m -2 ·s -1 ) and the subsequent restoration were compared between two superhigh_yield rice hybrids (Liangyoupeijiu and Hua_an 3, the newly developed rice hybrids from two parental lines) and the traditional rice hybrid Shanyou 63 developed from three parental lines. The results showed that the maximal efficiency of PSⅡ photochemistry ( Fv/Fm ), the efficiency of excitation energy capture by open PSⅡ centers ( Fv′/Fm′ ), and the yield of PSⅡ electron transport ( Φ PSⅡ ) of the three rice hybrids decreased during photoinhibition. However, a greater decrease in Fv/Fm , Fv′/Fm′ , and Φ PSⅡ was observed in Shanyou 63 than in Liangyoupeijiu and Hua_an 3. At the same time, the components of xanthophyll cycle, antherxanthin (A) and zeathanxin (Z) increased rapidly while violaxanthin (V) decreased considerably. Both the rate of accumulation and the amount of A and Z in the two superhigh_yield rice hybrids were higher than that in Shanyou 63. The de_epoxidation state (DES) of xanthophyll cycle increased rapidly with the fast accumulation of A and Z, and reached the maximal level after first 30 min during photoinhibition. Of the three hybrids, the increasing rate of DES in Liangyoupeijiu and Hua_an 3 was higher than that in Shanyou 63. After photoinhibition treatment, the plant materials were transferred to a dim light (70 μmol photons·m -2 ·s -1 ) for restoration. During restoration, both chlorophyll fluorescence parameters and xanthophyll cycle relaxed gradually, but the rate and level of restoration in the two superhigh_yield rice hybrids were higher than those in Shanyou 63. Our results suggest that Liangyoupeijiu and Hua_an 3 had higher resistance to photoinhibition and higher capacity of non_radiative energy dissipation associated with xanthophyll cycle, as well as higher rate of restoration after photoinhibition, than Shanyou 63 when subjected to strong light.展开更多
Solar energy is the primary driving force behind a planet’s climate system,and surface albedo plays a key role in determining the energy budget of the planet.Coupling the Snow,Ice,and Aerosol Radiation(SNICAR)with th...Solar energy is the primary driving force behind a planet’s climate system,and surface albedo plays a key role in determining the energy budget of the planet.Coupling the Snow,Ice,and Aerosol Radiation(SNICAR)with the Laboratoire de Météorologie Dynamique(LMD)Mars General Circulation Model(MGCM)to create a new coupled model leads to an approximately 4%drop in the net CO2 ice deposition on Mars.Newly simulated surface albedo affects the concentration of gaseous species in the Martian atmosphere(condensation-sublimation cycle).The new set-up also impacts the solar energy available in the atmosphere.These two effects together lead to subsequent and significant changes in other chemical species in the Martian atmosphere.Compared with results of the MGCM model alone,in the new coupled model CO2(gas)and O3 show a drop of about 1.17%and 8.59%in their respective concentrations,while H2O(vapor)and CO show an increase of about 13.63%and 0.56%in their respective concentrations.Among trace species,OH shows a maximum increase of about 29.44%,while the maximum drop of 11.5%is observed in the O concentration.Photochemically neutral species such as Ar and N2 remain unaffected by the albedo changes.展开更多
We have presented the synthesis and characterization of three new bromo substituted stilbene derivatives, p-3,4,5-trimethoxy-p′- 2,3,4,5,6-pentabromostilbene （C1）, p-N,N-dimethylamino-p′-2,3,4,5,6-pentabromostilbe...We have presented the synthesis and characterization of three new bromo substituted stilbene derivatives, p-3,4,5-trimethoxy-p′- 2,3,4,5,6-pentabromostilbene （C1）, p-N,N-dimethylamino-p′-2,3,4,5,6-pentabromostilbene （C2） and p-N,N-diphenylamino-p′- 2,3,4,5,6-pentabromostilbene （C3） in this letter. The UV/vis absorption and photoluminescence were investigated in various solvents. The maximal absorption wavelength of C1 exhibited blue-shift to those of C2 and C3 in different solvents. No florescence emission could be detected for these compounds at room temperature. Singlet oxygen could be efficiently produced with these sensitizers under near-ultraviolet and visible light irradiation.展开更多
Diphenylchlorin (DPC) and diphenylbacteriochlorin (DPBC) were synthesized for the first time from reduction of 5,10-diphenylporphyrin (DPP). As photosensitizers they have sizable absorption in the red region of the vi...Diphenylchlorin (DPC) and diphenylbacteriochlorin (DPBC) were synthesized for the first time from reduction of 5,10-diphenylporphyrin (DPP). As photosensitizers they have sizable absorption in the red region of the visible spectrum. The high yield of DPC.-photosensitized generation Of O-1(2), and the EPR studies in homogenerous solution showed that the photodynamic action of DPP-based photosensitizers may proceed via type I and type II machanisms.展开更多
Marine inorganic photochemistry, as one of the important branches of marine chemistry, is significantly connected with marine biology, marine ecology, marine geochemistry and marine environment, and plays an important...Marine inorganic photochemistry, as one of the important branches of marine chemistry, is significantly connected with marine biology, marine ecology, marine geochemistry and marine environment, and plays an important role in the development of marine sciences. To date, lots of investigations in the field have been conducted home and abroad. As for the following development of marine inorganic photochemistry, it is greatly of significance to summarize these research works. This paper detailedly summarizes the present research progress in the photochemistry of Fe, Mn and Cu, with an emphasis on investigations on photochemical processes which could affect existing forms of these metal elements in seawater. The problems and shortcomings in the study field are pointed out and some suggestions for the future study are put forward.展开更多
Direct photolysis and quenching experiments with styrene oxide support the existence of an efficient triplet photochemical pathway to benzyl radical formation. Similar photolytic behavior for styrene glycol carbonate ...Direct photolysis and quenching experiments with styrene oxide support the existence of an efficient triplet photochemical pathway to benzyl radical formation. Similar photolytic behavior for styrene glycol carbonate strongly supports the 1,3-diradical, resulting from the scission of the benzylic C-O bond, as the geometric source of the triplet pathway. Primary photoproducts were determined by both NMR and HPLC analysis and we observed that toluene and bibenzyl were both primary photoproducts, not secondary photoproducts.展开更多
High-energy-density fuels are important for volume-limited aerospace vehicles,but the increase in fuel energy density always leads to poor cryogenic performance.Herein,we investigated the transposed Paternò-B...High-energy-density fuels are important for volume-limited aerospace vehicles,but the increase in fuel energy density always leads to poor cryogenic performance.Herein,we investigated the transposed Paternò-Büchi reaction of biomass cyclic ketone and cyclic alkene to synthesize a new kind of alkyl-substituted polycyclic hydrocarbon fuel with high energy density and good cryogenic performance.The triplet-energy-quenching results and phosphorescent emission spectra reveal the sensitization mechanism of the reaction,including photosensitizer excitation,triplettriplet energy transfer,cyclization,and relaxation,and the possible reaction path was revealed by the density functional theory(DFT)calculations.The reaction conditions of photosensitizer type and addition,molar ratio of substrates,reaction temperature,and incident light intensity were optimized,with the target product yield achieving 65.5%.Moreover,the reaction dynamics of the reaction rate versus the light intensity are established.After the hydrogenation-deoxygenation reaction,three fuels with a high density of 0.864-0.938 g·ml^(-1) and a low freezing point of<-55℃ are obtained.This work provides a benign and effective approach to synthesize high-performance fuels.展开更多
文摘PSⅡ photochemistry and xanthophyll cycle during photoinhibition (exposed to strong light of 2 000 μmol photons·m -2 ·s -1 ) and the subsequent restoration were compared between two superhigh_yield rice hybrids (Liangyoupeijiu and Hua_an 3, the newly developed rice hybrids from two parental lines) and the traditional rice hybrid Shanyou 63 developed from three parental lines. The results showed that the maximal efficiency of PSⅡ photochemistry ( Fv/Fm ), the efficiency of excitation energy capture by open PSⅡ centers ( Fv′/Fm′ ), and the yield of PSⅡ electron transport ( Φ PSⅡ ) of the three rice hybrids decreased during photoinhibition. However, a greater decrease in Fv/Fm , Fv′/Fm′ , and Φ PSⅡ was observed in Shanyou 63 than in Liangyoupeijiu and Hua_an 3. At the same time, the components of xanthophyll cycle, antherxanthin (A) and zeathanxin (Z) increased rapidly while violaxanthin (V) decreased considerably. Both the rate of accumulation and the amount of A and Z in the two superhigh_yield rice hybrids were higher than that in Shanyou 63. The de_epoxidation state (DES) of xanthophyll cycle increased rapidly with the fast accumulation of A and Z, and reached the maximal level after first 30 min during photoinhibition. Of the three hybrids, the increasing rate of DES in Liangyoupeijiu and Hua_an 3 was higher than that in Shanyou 63. After photoinhibition treatment, the plant materials were transferred to a dim light (70 μmol photons·m -2 ·s -1 ) for restoration. During restoration, both chlorophyll fluorescence parameters and xanthophyll cycle relaxed gradually, but the rate and level of restoration in the two superhigh_yield rice hybrids were higher than those in Shanyou 63. Our results suggest that Liangyoupeijiu and Hua_an 3 had higher resistance to photoinhibition and higher capacity of non_radiative energy dissipation associated with xanthophyll cycle, as well as higher rate of restoration after photoinhibition, than Shanyou 63 when subjected to strong light.
基金partially supported by DST-INSPIRE Faculty Award。
文摘Solar energy is the primary driving force behind a planet’s climate system,and surface albedo plays a key role in determining the energy budget of the planet.Coupling the Snow,Ice,and Aerosol Radiation(SNICAR)with the Laboratoire de Météorologie Dynamique(LMD)Mars General Circulation Model(MGCM)to create a new coupled model leads to an approximately 4%drop in the net CO2 ice deposition on Mars.Newly simulated surface albedo affects the concentration of gaseous species in the Martian atmosphere(condensation-sublimation cycle).The new set-up also impacts the solar energy available in the atmosphere.These two effects together lead to subsequent and significant changes in other chemical species in the Martian atmosphere.Compared with results of the MGCM model alone,in the new coupled model CO2(gas)and O3 show a drop of about 1.17%and 8.59%in their respective concentrations,while H2O(vapor)and CO show an increase of about 13.63%and 0.56%in their respective concentrations.Among trace species,OH shows a maximum increase of about 29.44%,while the maximum drop of 11.5%is observed in the O concentration.Photochemically neutral species such as Ar and N2 remain unaffected by the albedo changes.
基金support from National Natural Science Foundation of China(Nos. 20776165,20702065,20872184)Key Foundation of Chongqing Science and Technology Commission"(No.CSTC 2008BA4020)+1 种基金"A Foundation for the Author of National Excellent Doctoral Dissertation of PR China(200735)"for financial supportsponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry as well(Nos.20071108-1, 20071108-5).
文摘We have presented the synthesis and characterization of three new bromo substituted stilbene derivatives, p-3,4,5-trimethoxy-p′- 2,3,4,5,6-pentabromostilbene （C1）, p-N,N-dimethylamino-p′-2,3,4,5,6-pentabromostilbene （C2） and p-N,N-diphenylamino-p′- 2,3,4,5,6-pentabromostilbene （C3） in this letter. The UV/vis absorption and photoluminescence were investigated in various solvents. The maximal absorption wavelength of C1 exhibited blue-shift to those of C2 and C3 in different solvents. No florescence emission could be detected for these compounds at room temperature. Singlet oxygen could be efficiently produced with these sensitizers under near-ultraviolet and visible light irradiation.
文摘Diphenylchlorin (DPC) and diphenylbacteriochlorin (DPBC) were synthesized for the first time from reduction of 5,10-diphenylporphyrin (DPP). As photosensitizers they have sizable absorption in the red region of the visible spectrum. The high yield of DPC.-photosensitized generation Of O-1(2), and the EPR studies in homogenerous solution showed that the photodynamic action of DPP-based photosensitizers may proceed via type I and type II machanisms.
基金supported by the National Natural Science Foundation of China(No.40176023).
文摘Marine inorganic photochemistry, as one of the important branches of marine chemistry, is significantly connected with marine biology, marine ecology, marine geochemistry and marine environment, and plays an important role in the development of marine sciences. To date, lots of investigations in the field have been conducted home and abroad. As for the following development of marine inorganic photochemistry, it is greatly of significance to summarize these research works. This paper detailedly summarizes the present research progress in the photochemistry of Fe, Mn and Cu, with an emphasis on investigations on photochemical processes which could affect existing forms of these metal elements in seawater. The problems and shortcomings in the study field are pointed out and some suggestions for the future study are put forward.
文摘Direct photolysis and quenching experiments with styrene oxide support the existence of an efficient triplet photochemical pathway to benzyl radical formation. Similar photolytic behavior for styrene glycol carbonate strongly supports the 1,3-diradical, resulting from the scission of the benzylic C-O bond, as the geometric source of the triplet pathway. Primary photoproducts were determined by both NMR and HPLC analysis and we observed that toluene and bibenzyl were both primary photoproducts, not secondary photoproducts.
基金support from National Key Research and Development Program of China(2021YFC2103704)the National Natural Science Foundation of China(22222808,21978200)the Haihe Laboratory of Sustainable Chemical Transformations.
文摘High-energy-density fuels are important for volume-limited aerospace vehicles,but the increase in fuel energy density always leads to poor cryogenic performance.Herein,we investigated the transposed Paternò-Büchi reaction of biomass cyclic ketone and cyclic alkene to synthesize a new kind of alkyl-substituted polycyclic hydrocarbon fuel with high energy density and good cryogenic performance.The triplet-energy-quenching results and phosphorescent emission spectra reveal the sensitization mechanism of the reaction,including photosensitizer excitation,triplettriplet energy transfer,cyclization,and relaxation,and the possible reaction path was revealed by the density functional theory(DFT)calculations.The reaction conditions of photosensitizer type and addition,molar ratio of substrates,reaction temperature,and incident light intensity were optimized,with the target product yield achieving 65.5%.Moreover,the reaction dynamics of the reaction rate versus the light intensity are established.After the hydrogenation-deoxygenation reaction,three fuels with a high density of 0.864-0.938 g·ml^(-1) and a low freezing point of<-55℃ are obtained.This work provides a benign and effective approach to synthesize high-performance fuels.
