Nitrogen(N)present in drinking water as dissolved nitrates can directly affect people’s health,making it important to control N pollution in water source areas.N pollution caused by agricultural fertilizers can be co...Nitrogen(N)present in drinking water as dissolved nitrates can directly affect people’s health,making it important to control N pollution in water source areas.N pollution caused by agricultural fertilizers can be controlled by reducing the amount of fertilizer applied,but pollution caused by soil and water erosion in hilly areas can only be controlled by conservation forests.The catchment area around Fushi Reservoir was selected as a test site and mechanisms of N loss from a vertical spatial perspective through field observations were determined.The main N losses occurred from June to September,accounting for 85.9-95.9%of the annual loss,with the losses in June and July accounting for 46.0%of the total,and in August and September for 41.9%.The N leakage from the water source area was effectively reduced by 38.2%through the optimization of the stand structure of the conservation forests.Establishing well-structured forests for water conservation is crucial to ensure the security of drinking water.This preliminary research lays the foundation for revealing then loss mechanisms in water source areas and improving the control of non-point source pollution in these areas.展开更多
Perovskite lasers,due to their superiority in feasible production and wavelength tunability,find application in optical communication[1].Since the discovery of stimulated emission from CsPbCl3 microcrystalline at liqu...Perovskite lasers,due to their superiority in feasible production and wavelength tunability,find application in optical communication[1].Since the discovery of stimulated emission from CsPbCl3 microcrystalline at liquid-nitrogen temperature[2],successive breakthroughs in perovskite lasers have been made.展开更多
With the purpose of cultivating students' "STS" quality,multiple teaching methods were discussed,including the students-oriented teaching,group discussion,case teaching,interactive teaching,little teache...With the purpose of cultivating students' "STS" quality,multiple teaching methods were discussed,including the students-oriented teaching,group discussion,case teaching,interactive teaching,little teacher teaching,practical teaching and flexible assessment,etc.,thus the students learning initiative could be greatly stimulated,their comprehensive ability can be improved,and more excellent talents can be cultivated.展开更多
Recently,an effective exciton diffusion length L exceeding 100μm has been reported for organic–inorganic halide perovskites owing to both the high mobility and ultra-long lifetime of the excitons;however,the origin ...Recently,an effective exciton diffusion length L exceeding 100μm has been reported for organic–inorganic halide perovskites owing to both the high mobility and ultra-long lifetime of the excitons;however,the origin of ultra-long L is still unclear in nature.In some photoelectric materials,reverse intersystem crossing(RISC)from the triplet to the singlet state can enhance the quantum yield of photoluminescence greatly.In this study,our theoretical investigation indicated that the energy difference E_(st )between the singlet state and the triplet state of CH_3NH_3PbI_3was less than 0.1 e V,which represents one crucial prerequisite for the occurrence of RISC.Meanwhile,the experimental results showed that the photoluminescence lifetime increased with the increasing temperature,a typical feature of RISC.Based on this study,we put forward the hypothesis that the ultra-long lifetime of excitons in organic–inorganic halide perovskite might be caused by the RISC process.This may provide a new insight into the important photophysical properties of such novel photovoltaic materials.展开更多
Charge carrier dynamics essentially determines the performance of various optoelectronic applications of colloidal semiconductor nanocrystals.Among them,two-dimensional nanoplatelets provide new adjustment freedom for...Charge carrier dynamics essentially determines the performance of various optoelectronic applications of colloidal semiconductor nanocrystals.Among them,two-dimensional nanoplatelets provide new adjustment freedom for their unique core/crown heterostructures.Herein,we demonstrate that by fine-tuning the core size and the lateral quantum confinement,the charge carrier transfer rate from the crown to the core can be varied by one order of magnitude in CdSe/CdSeS core/alloy-crown nanoplatelets.In addition,the transfer can be affected by a carrier blocking mechanism,i.e.,the filled carriers hinder further possible transfer.Furthermore,we found that the biexciton interaction is oppositely affected by quantum confinement and electron delocalization,resulting in a non-monotonic variation of the biexciton binding energy with the emission wavelength.This work provides new observations and insights into the charge carrier transfer dynamics and exciton interactions in colloidal nanoplatelets and will promote their further applications in lasing,display,sensing,etc.展开更多
Screening potential plant species is a crucial consideration in phytoremediation technology.Our previous study demonstrated that Rhus chinensis Mill. seedlings had potentials for phytoremediation of Pb contaminated so...Screening potential plant species is a crucial consideration in phytoremediation technology.Our previous study demonstrated that Rhus chinensis Mill. seedlings had potentials for phytoremediation of Pb contaminated soil. However, its bioaccumulation and tolerance characteristics remain unclear. Seedling growth, LMWOAs secreted by roots, Pb subcellular distribution and chemical forms, and mineral elements in R. chinensis tissues were evaluated under different Pb concentrations(0, 25, 50, 100, 200 and 400 mg/L) in culture solution at14 days after planting. R. chinensis did not show visual symptoms of Pb toxicity under lower Pb treatments; however, Pb significantly declined the growth of seedlings under higher Pb treatments. Higher Pb stress also decreased the concentrations of nitrogen in leaves, but increased the concentrations of P and K in roots. Pb stress also decreased Mn concentrations in leaves. A great quantity of Pb was uptake and mostly retained in R. chinensis roots.Nonetheless, R. chinensis can still concentrate 459.3 and 1102.7 mg/kg Pb in leaves and stems,respectively. Most of Pb in R. chinensis tissues was stored in the cell wall with HAc-, HCl-, and NaC l-extractable form. LMWOAs secreted by R. chinensis roots showed a strong positive correlation with Pb concentrations in all plant tissues and with P in roots. Our results suggested that Pb deposited in the cell wall and integration with phosphate or oxalate might be responsible for the tolerance of R. chinensis under Pb stress in short period.展开更多
Large and complex construction projects face risk from various sources and the successful completion of such projects depends on effective risk management.This study investigates the risk faced by Chinese firms partic...Large and complex construction projects face risk from various sources and the successful completion of such projects depends on effective risk management.This study investigates the risk faced by Chinese firms participating in constructing AP1000 nuclear power plants in China.AP1000 nuclear reactors are new,Generation III+ reactors designed by Westinghouse and to be built first in China.The semi-structured interview approach is used to elicit information from experts involved in the AP1000 projects in China.Based on the interviews,various sources of risk are identified.In addition to general risks that megaprojects normally face,there are unique risks that arise from various sources such as technological,political,organizational,and individual personnel risks.Risk management strategies are proposed to manage general and unique risks identified in the study.The findings of this study would be helpful for Chinese companies involved in the construction of AP1000 nuclear power plants to mitigate the risks associated with the projects.展开更多
For the first time in 2009,the inorganic-organic hybrid perovskite materials were applied in liquid dye-sensitized solar cells.In 2013,the power conversion efficiency successfully reached 15%,followed by great amount ...For the first time in 2009,the inorganic-organic hybrid perovskite materials were applied in liquid dye-sensitized solar cells.In 2013,the power conversion efficiency successfully reached 15%,followed by great amount of research papers bursting out.Till August 2014,the highest efficiency is certified to 17.9%,and the reported efficiency is even up to 19.3%.They quickly go beyond dye-sensitized solar cells and organic solar cells.It is expected the perovskite has its efficiency same to the single-crystal silicon cells.The“game changer”of solar cells is coming.The perovskite solar cells are cheap and easily to be made,which will benefit both science and industry.This review summarized recent development of both perovskite materials and solar cell devices,not only including new material developments of perovskite compositions,structures,and fabrication methods,but also focusing on device structures,charge transfer mechanism and stability properties of perovskite solar cells.Their perspective is also estimated.展开更多
Autoreactive CD8^(+)T cells,which play an indispensable role inβcell destruction,represent an emerging target for the prevention of type 1 diabetes(T1D).Altered peptide ligands(APLs)can efficiently induce antigen-spe...Autoreactive CD8^(+)T cells,which play an indispensable role inβcell destruction,represent an emerging target for the prevention of type 1 diabetes(T1D).Altered peptide ligands(APLs)can efficiently induce antigen-specific T cells anergy,apoptosis or shifts in the immune response.Here,we found that HLA-A*0201-restricted CD8^(+)T cell responses against a primaryβ-cell autoantigen insulin epitope InsB15–14 were present in both NOD.β2m null.HHD NOD mice and T1D patients.We generated several APL candidates for InsB15–14 by residue substitution at the p6 position.Only H6F exhibited an inhibitory effect on mInsB1_(5–14)-specific CD8^(+)T cell responses in vitro.H6F treatment significantly reduced the T1D incidence,which was accompanied by diminished autoreactive CD8^(+)T cell responses to mInsB15-14,inhibited infiltration of CD8^(+)and CD4^(+)T cells in the pancreas and reduced pro-inflammatory cytokine production in pancreatic and splenic T cells in NOD.β2m^(null).HHD mice.Mechanistically,H6F treatment significantly augmented a tiny portion of CD8^(+)CD25^(+)Foxp3^(+)T cells in the spleen and especially in the pancreas.This subset exhibited typical Treg phenotypes and required peptide-specific restimulation to exert immunosuppressive activity.Therefore,this APL H6F may be a promising candidate with potential clinical application value for antigen-specific prevention of T1D.展开更多
The steady-state absorption and fluorescence emission positions of diprotonated meso-tetrakis(4-sulfonatophenyl)porphyrin(H4TPPS2-)are dependent on the polarity of the selected two solid ionic liquids(ILs)and are red-...The steady-state absorption and fluorescence emission positions of diprotonated meso-tetrakis(4-sulfonatophenyl)porphyrin(H4TPPS2-)are dependent on the polarity of the selected two solid ionic liquids(ILs)and are red-shifted with the increase of cation size.The solvation dynamics process of H4TPPS2-in these ILs occurs on two well-separated time scales.The short components with121.2–128.6 ps arise from the local motion of the ion-pairs in close proximity to the porphine core,and the long components with 1056.6–1261.8 ps are due to the collective translation motions of the ion-pairs.The dynamic Stokes shifts and the relaxation times increase with the increasing cation size of the ILs.展开更多
The quantum Toffoli gate is one of the most important three-qubit gates,but it is challenging to construct a chip according to the complicated traditional circuit.Using the optimized 3D configuration with an overpass ...The quantum Toffoli gate is one of the most important three-qubit gates,but it is challenging to construct a chip according to the complicated traditional circuit.Using the optimized 3D configuration with an overpass waveguide to reduce the circuit complexity,we successfully fabricate an on-chip path encoded photonic quantum Toffoli gate enabled by the 3D capability of the femtosecond laser direct writing(FLDW)for the first time to our knowledge,whose truth-table fidelity is higher than 85.5%.Furthermore,a path encoded four-qubit controlled-controlled-controlled NOT gate is written to confirm the scalability of this resource-saving technique.This work paves the way for the FLDW of more complex and powerful photonic quantum computation chips.展开更多
基金supported by Zhejiang A&F University(2022LFR083)Key R&D Program of Zhejiang Province(2021C02038)the International Centre for Bamboo and Rattan(1632021006)。
文摘Nitrogen(N)present in drinking water as dissolved nitrates can directly affect people’s health,making it important to control N pollution in water source areas.N pollution caused by agricultural fertilizers can be controlled by reducing the amount of fertilizer applied,but pollution caused by soil and water erosion in hilly areas can only be controlled by conservation forests.The catchment area around Fushi Reservoir was selected as a test site and mechanisms of N loss from a vertical spatial perspective through field observations were determined.The main N losses occurred from June to September,accounting for 85.9-95.9%of the annual loss,with the losses in June and July accounting for 46.0%of the total,and in August and September for 41.9%.The N leakage from the water source area was effectively reduced by 38.2%through the optimization of the stand structure of the conservation forests.Establishing well-structured forests for water conservation is crucial to ensure the security of drinking water.This preliminary research lays the foundation for revealing then loss mechanisms in water source areas and improving the control of non-point source pollution in these areas.
基金supported by the National Natural Science Foundation of China(11874074 and 11527901)the National Natural Science Foundation of China(51773045,21772030,51922032,and 21961160720)for financial support+2 种基金the National Key Research and Development Program of China(2018YFA0704400)the National Key Research and Development Program of China(2017YFA0206600)Guangdong Major Project of Basic and Applied Basic Research(2020B0301030009)。
文摘Perovskite lasers,due to their superiority in feasible production and wavelength tunability,find application in optical communication[1].Since the discovery of stimulated emission from CsPbCl3 microcrystalline at liquid-nitrogen temperature[2],successive breakthroughs in perovskite lasers have been made.
基金Supported by Education Teaching Program of Southwest University(2010JY094)
文摘With the purpose of cultivating students' "STS" quality,multiple teaching methods were discussed,including the students-oriented teaching,group discussion,case teaching,interactive teaching,little teacher teaching,practical teaching and flexible assessment,etc.,thus the students learning initiative could be greatly stimulated,their comprehensive ability can be improved,and more excellent talents can be cultivated.
基金The financial supports of the National Natural Science Foundation of China (grant nos. 21373042, 21677029 and 51402036)the Fundamental Research Funds for the Central Universities (grant no. DUT15YQ109)
文摘Recently,an effective exciton diffusion length L exceeding 100μm has been reported for organic–inorganic halide perovskites owing to both the high mobility and ultra-long lifetime of the excitons;however,the origin of ultra-long L is still unclear in nature.In some photoelectric materials,reverse intersystem crossing(RISC)from the triplet to the singlet state can enhance the quantum yield of photoluminescence greatly.In this study,our theoretical investigation indicated that the energy difference E_(st )between the singlet state and the triplet state of CH_3NH_3PbI_3was less than 0.1 e V,which represents one crucial prerequisite for the occurrence of RISC.Meanwhile,the experimental results showed that the photoluminescence lifetime increased with the increasing temperature,a typical feature of RISC.Based on this study,we put forward the hypothesis that the ultra-long lifetime of excitons in organic–inorganic halide perovskite might be caused by the RISC process.This may provide a new insight into the important photophysical properties of such novel photovoltaic materials.
基金This work was supported by the National Natural Science Foundation of China(No.61875002)the National Key R&D Program of China(No.2018YFA0306302)+4 种基金the Beijing Natural Science Foundation(No.Z190005)the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices(No.KF202208)The author acknowledges the support of the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000)the National Natural Science Foundation of China(Nos.11874130 and 22073022)the support from the DNL Cooperation Fund,CAS(No.DNL202016)of Dalian National Laboratory for Clean Energy。
文摘Charge carrier dynamics essentially determines the performance of various optoelectronic applications of colloidal semiconductor nanocrystals.Among them,two-dimensional nanoplatelets provide new adjustment freedom for their unique core/crown heterostructures.Herein,we demonstrate that by fine-tuning the core size and the lateral quantum confinement,the charge carrier transfer rate from the crown to the core can be varied by one order of magnitude in CdSe/CdSeS core/alloy-crown nanoplatelets.In addition,the transfer can be affected by a carrier blocking mechanism,i.e.,the filled carriers hinder further possible transfer.Furthermore,we found that the biexciton interaction is oppositely affected by quantum confinement and electron delocalization,resulting in a non-monotonic variation of the biexciton binding energy with the emission wavelength.This work provides new observations and insights into the charge carrier transfer dynamics and exciton interactions in colloidal nanoplatelets and will promote their further applications in lasing,display,sensing,etc.
基金The authors gratefully acknowledge the financial support from the National Basic Research Program （2011CB933303 and 2013CB921904） and the National Natural Science Foundation of China （NSFC） （21321001, 21371012 and 11134001）.
基金supported by the National Natural Science Funds of China (No. 31300509)the special funds from the Central Scientific Research Institute of Public Welfare (No.CAFYBB2014QB016)the Natural Science Funds of Beijing (No. 8152032)
文摘Screening potential plant species is a crucial consideration in phytoremediation technology.Our previous study demonstrated that Rhus chinensis Mill. seedlings had potentials for phytoremediation of Pb contaminated soil. However, its bioaccumulation and tolerance characteristics remain unclear. Seedling growth, LMWOAs secreted by roots, Pb subcellular distribution and chemical forms, and mineral elements in R. chinensis tissues were evaluated under different Pb concentrations(0, 25, 50, 100, 200 and 400 mg/L) in culture solution at14 days after planting. R. chinensis did not show visual symptoms of Pb toxicity under lower Pb treatments; however, Pb significantly declined the growth of seedlings under higher Pb treatments. Higher Pb stress also decreased the concentrations of nitrogen in leaves, but increased the concentrations of P and K in roots. Pb stress also decreased Mn concentrations in leaves. A great quantity of Pb was uptake and mostly retained in R. chinensis roots.Nonetheless, R. chinensis can still concentrate 459.3 and 1102.7 mg/kg Pb in leaves and stems,respectively. Most of Pb in R. chinensis tissues was stored in the cell wall with HAc-, HCl-, and NaC l-extractable form. LMWOAs secreted by R. chinensis roots showed a strong positive correlation with Pb concentrations in all plant tissues and with P in roots. Our results suggested that Pb deposited in the cell wall and integration with phosphate or oxalate might be responsible for the tolerance of R. chinensis under Pb stress in short period.
文摘Large and complex construction projects face risk from various sources and the successful completion of such projects depends on effective risk management.This study investigates the risk faced by Chinese firms participating in constructing AP1000 nuclear power plants in China.AP1000 nuclear reactors are new,Generation III+ reactors designed by Westinghouse and to be built first in China.The semi-structured interview approach is used to elicit information from experts involved in the AP1000 projects in China.Based on the interviews,various sources of risk are identified.In addition to general risks that megaprojects normally face,there are unique risks that arise from various sources such as technological,political,organizational,and individual personnel risks.Risk management strategies are proposed to manage general and unique risks identified in the study.The findings of this study would be helpful for Chinese companies involved in the construction of AP1000 nuclear power plants to mitigate the risks associated with the projects.
基金the National Natural Science Foundation of China(Nos.61177020,11121091)the National Basic Research Program of China(No.2013CB921904).
文摘For the first time in 2009,the inorganic-organic hybrid perovskite materials were applied in liquid dye-sensitized solar cells.In 2013,the power conversion efficiency successfully reached 15%,followed by great amount of research papers bursting out.Till August 2014,the highest efficiency is certified to 17.9%,and the reported efficiency is even up to 19.3%.They quickly go beyond dye-sensitized solar cells and organic solar cells.It is expected the perovskite has its efficiency same to the single-crystal silicon cells.The“game changer”of solar cells is coming.The perovskite solar cells are cheap and easily to be made,which will benefit both science and industry.This review summarized recent development of both perovskite materials and solar cell devices,not only including new material developments of perovskite compositions,structures,and fabrication methods,but also focusing on device structures,charge transfer mechanism and stability properties of perovskite solar cells.Their perspective is also estimated.
基金supported by the National Natural Science Foundation of China(No.31570931 and No.31771002)the National Key Project for Research&Development of China(Grant no.2016YFA0502204).
文摘Autoreactive CD8^(+)T cells,which play an indispensable role inβcell destruction,represent an emerging target for the prevention of type 1 diabetes(T1D).Altered peptide ligands(APLs)can efficiently induce antigen-specific T cells anergy,apoptosis or shifts in the immune response.Here,we found that HLA-A*0201-restricted CD8^(+)T cell responses against a primaryβ-cell autoantigen insulin epitope InsB15–14 were present in both NOD.β2m null.HHD NOD mice and T1D patients.We generated several APL candidates for InsB15–14 by residue substitution at the p6 position.Only H6F exhibited an inhibitory effect on mInsB1_(5–14)-specific CD8^(+)T cell responses in vitro.H6F treatment significantly reduced the T1D incidence,which was accompanied by diminished autoreactive CD8^(+)T cell responses to mInsB15-14,inhibited infiltration of CD8^(+)and CD4^(+)T cells in the pancreas and reduced pro-inflammatory cytokine production in pancreatic and splenic T cells in NOD.β2m^(null).HHD mice.Mechanistically,H6F treatment significantly augmented a tiny portion of CD8^(+)CD25^(+)Foxp3^(+)T cells in the spleen and especially in the pancreas.This subset exhibited typical Treg phenotypes and required peptide-specific restimulation to exert immunosuppressive activity.Therefore,this APL H6F may be a promising candidate with potential clinical application value for antigen-specific prevention of T1D.
基金supported by the National Natural Science Foundation of China(20875010)
文摘The steady-state absorption and fluorescence emission positions of diprotonated meso-tetrakis(4-sulfonatophenyl)porphyrin(H4TPPS2-)are dependent on the polarity of the selected two solid ionic liquids(ILs)and are red-shifted with the increase of cation size.The solvation dynamics process of H4TPPS2-in these ILs occurs on two well-separated time scales.The short components with121.2–128.6 ps arise from the local motion of the ion-pairs in close proximity to the porphine core,and the long components with 1056.6–1261.8 ps are due to the collective translation motions of the ion-pairs.The dynamic Stokes shifts and the relaxation times increase with the increasing cation size of the ILs.
基金National Key Research and Development Program of China(2018YFB1107205,2016YFA0301302)National Natural Science Foundation of China(12134001,61590933,61590932,11527901,11774333,62061160487)+2 种基金Joint Fund for Equipment Pre-research Space Science and Technology(6141B06140601)Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB24030601)Fundamental Research Funds for the Central Universities。
文摘The quantum Toffoli gate is one of the most important three-qubit gates,but it is challenging to construct a chip according to the complicated traditional circuit.Using the optimized 3D configuration with an overpass waveguide to reduce the circuit complexity,we successfully fabricate an on-chip path encoded photonic quantum Toffoli gate enabled by the 3D capability of the femtosecond laser direct writing(FLDW)for the first time to our knowledge,whose truth-table fidelity is higher than 85.5%.Furthermore,a path encoded four-qubit controlled-controlled-controlled NOT gate is written to confirm the scalability of this resource-saving technique.This work paves the way for the FLDW of more complex and powerful photonic quantum computation chips.
