The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportio...The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportion remains one challenge for the catalyst design.Herein,a Ni2+-loaded porous poly(ionic liquids)(PIL)precursor synthesized through the free radical self-polymerization of the ionic liquid monomer,1-allyl-3-vinylimidazolium chloride,was pyrolyzed to prepare the Ni,N co-doped carbon materials,in which the proportion of Ni SAs and NPs could be facilely modulated by controlling the annealing temperature.The catalyst Ni-NC-1000 with a moderate proportion of Ni SAs and NPs exhibited high efficiency in the electrocatalytic conversion of CO_(2)into CO.Operando Ni K-edge X-ray absorption near-edge structure(XANES)spectra and theoretical calculations were conducted to gain insight into the synergy of Ni SAs and NPs.The charge transfer from Ni NPs to the surrounding carbon layer and then to the Ni SAs resulted in the electron-enriched Ni SAs active sites.In the electroreduction of CO_(2),the coexistence of Ni SAs and NPs strengthened the CO_(2)activation and the affinity towards the key intermediate of*COOH,lowering the free energy for the potential-determining*CO_(2)→*COOH step,and therefore promoted the catalysis efficiency.展开更多
A nine-year-old girl with Staphylococcus epidermidis meningitis combined with acute disseminated encephalomyelitis （ADEM） was enrolled in the present study, and exhibited sustained fever and headache for 5 days and ...A nine-year-old girl with Staphylococcus epidermidis meningitis combined with acute disseminated encephalomyelitis （ADEM） was enrolled in the present study, and exhibited sustained fever and headache for 5 days and a single seizure episode. Meningeal irritation and disturbance of consciousness were apparent. Cerebrospinal fluid examination revealed increased protein level and pleocytosis. Cerebrospinal fluid culture demonstrated Staphylococcus epidermidis growth. The patient was treated with intravenous cefotaxime, intravenous dexamethasone, and decreasing intracranial pressure for 3 weeks. Seizures and fever symptoms improved, but disturbance of consciousness, muscle weakness, and bilateral limb paresis were significant. IgG index was elevated and oligoclonal bands were positive in the cerebrospinal fluid. Magnetic resonance imaging demonstrated high T2-weighted signals in subcortical white matter, which were consistent with ADEM. High-dose methylprednisolone for 3 days and a 6-day pulse therapy with immunoglobulins resulted in improved clinical symptoms and cerebrospinal fluid examination. The patient＇s temperature dropped to normal, and the headache disappeared. A Staphylococcus epidermidis infection associated with ADEM is uncommon in children. Results suggested that Staphylococcus epidermidis infection could be a pathogenic factor for ADEM, and ADEM is a complication of Staphylococcus epidermidis meningitis.展开更多
Recent submillimeter dust thermal emission observations have unveiled a significant number of inter-arm massive molecular clouds in M31.However,the effectiveness of this technique is limited to its sensitivity,making ...Recent submillimeter dust thermal emission observations have unveiled a significant number of inter-arm massive molecular clouds in M31.However,the effectiveness of this technique is limited to its sensitivity,making it challenging to study more distant galaxies.This study introduces an alternative approach,utilizing optical extinctions derived from space-based telescopes,with a focus on the forthcoming China Space Station Telescope(CSST).We first demonstrate the capability of this method by constructing dust extinction maps for 17 inter-arm massive molecular clouds in M31 using the Panchromatic Hubble Andromeda Treasury data.Our analysis reveals that inter-arm massive molecular clouds with an optical extinction(A_(V)) greater than 1.6 mag exhibit a notable A_(V) excess,facilitating their identification.The majority of these inter-arm massive molecular clouds show an A_(V) around 1 mag,aligning with measurements from our JCMT data.Further validation using a mock CSST RGB star catalog confirms the method's effectiveness.We show that the derived A_(V)values using CSST z and y photometries align more closely with the input values.Molecular clouds with A_(V)> 1.6 mag can also be identified using the CSST mock data.We thus claim that future CSST observation clouds provide an effective way for the detection of inter-arm massive molecular clouds with significant optical extinction in nearby galaxies.展开更多
Polyoxometalates(POMs)are molecular metal-oxide clusters with precise chemical composition and architecture.Besides their bioactivities,electron-rich POMs have shown potential for enhancing synergistic therapy,such as...Polyoxometalates(POMs)are molecular metal-oxide clusters with precise chemical composition and architecture.Besides their bioactivities,electron-rich POMs have shown potential for enhancing synergistic therapy,such as photothermal therapy(PTT),photodynamic therapy(PDT),and chemo-dynamic therapy(CDT),through near-infrared region(NIR)absorption and redox reactions.展开更多
N-alkylation of amines with alcohols is a promising green route for the synthesis of N-alkylamines, but the designation of highly active and stable heterogeneous catalysts remains one challenge. In this work, we initi...N-alkylation of amines with alcohols is a promising green route for the synthesis of N-alkylamines, but the designation of highly active and stable heterogeneous catalysts remains one challenge. In this work, we initiated the application of zeolite-encapsulated noble metal nanoparticles(NPs) in the N-alkylation of amines with aromatic alcohols. Platinum(Pt) NPs were directly confined into the framework of BEA zeolite with tunable Si/Al molar ratios and Na^(+) contents. The champion catalyst afforded the extremely high turnover number(TON) of 6,176 and turnover frequency(TOF) of 3,390 h^(-1) plus stable recyclability and broad substrate compatibility. The Na ions modulated the electronic state of Pt NPs to reach a moderate Pt–H strength, which wellbalanced the two crucial steps of dehydrogenation and H-transfer and accounted for the high catalytic performance. The encapsulation of zeolites provided spatial satisfaction for the synergy effect above and enhanced the stabilization of Pt NPs.展开更多
The authors investigate the effects of nanofillers with varying band‐gap energies on the space charge properties,breakdown field strength,and bulk resistivity of epoxy(EP)‐based composites.Additionally,the molecular...The authors investigate the effects of nanofillers with varying band‐gap energies on the space charge properties,breakdown field strength,and bulk resistivity of epoxy(EP)‐based composites.Additionally,the molecular orbital distribution of both the epoxy resin and nanofillers were examined through density functional theory.Experimental results indicate that the space charge accumulation within silicon dioxide/EP and germanium oxide/EP is reduced,leading to a more uniformly distributed electric field intensity within the specimen when compared to epoxy.As a result,both materials exhibit improved AC breakdown field strength and volume resistivity.Conversely,the amount of charge accumulated within tin dioxide/EP is higher,resulting in lower breakdown field strength than epoxy.The lowest unoccupied molecular orbital and the highest occupied molecular orbital energy level differences between epoxy and nanofillers introduce electron traps and hole traps at the interface,forming interfacial traps that affect the space charge distribution within the specimen,as well as the trap energy levels within the material.From the experimental results,shallow traps promote space charge accumulation and reduce the breakdown field strength,while deep traps have the opposite effect.展开更多
Although cesium lead halide perovskite(CsPbX3,X=Cl,Br,or I)nanocrystals(PNCs)have been rapidly developed for multiple optoelectronic applications due to their outstanding optical and transport properties,their device ...Although cesium lead halide perovskite(CsPbX3,X=Cl,Br,or I)nanocrystals(PNCs)have been rapidly developed for multiple optoelectronic applications due to their outstanding optical and transport properties,their device fabrication and commercialization have been limited by their low structural stability,especially under environmental conditions.In this work,a new approach has been developed to protect the surface of these nanocrystals,which results in enhanced chemical stability and optical properties.This method is based on the encapsulation of CsPbX3 NCs into a polyimide with intrinsic microporosity(PIM-PI),4,4′-(hexafluoroisopropylidene)diphthalic anhydride reacted with 2,4,6-trimethyl-m-phenylenediamine(6FDATrMPD).The presence of 6FDA-TrMPD as a protective layer can efficiently isolate NCs from an air environment and subsequently enhance their optical and photoluminescence stability.More specifically,comparing NCs treated with a polymer to as-synthesized nanocrystals after 168 h,we observe that the PL intensity decreased by 70%and 20%for the NCs before and after polymer treatment.In addition,the PNC film with a polymer shows a much longer excited-state lifetime than the as-synthesized nanocrystals,indicating that the surface trap states are significantly reduced in the treated PNCs.The enhancement in chemical and air stability,as well as optical behavior,will further improve the performance of CsPbBr3 PNCs yielding promising optical devices and paving the way for their production and implementation at a large scale.展开更多
基金National Natural Science Foundation of China(grants 22072065,22178162,and 22222806)Distinguished Youth Foundation of Jiangsu Province(grant BK20220053)Six talent peaks project in Jiangsu Province(grant JNHB-035)。
文摘The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportion remains one challenge for the catalyst design.Herein,a Ni2+-loaded porous poly(ionic liquids)(PIL)precursor synthesized through the free radical self-polymerization of the ionic liquid monomer,1-allyl-3-vinylimidazolium chloride,was pyrolyzed to prepare the Ni,N co-doped carbon materials,in which the proportion of Ni SAs and NPs could be facilely modulated by controlling the annealing temperature.The catalyst Ni-NC-1000 with a moderate proportion of Ni SAs and NPs exhibited high efficiency in the electrocatalytic conversion of CO_(2)into CO.Operando Ni K-edge X-ray absorption near-edge structure(XANES)spectra and theoretical calculations were conducted to gain insight into the synergy of Ni SAs and NPs.The charge transfer from Ni NPs to the surrounding carbon layer and then to the Ni SAs resulted in the electron-enriched Ni SAs active sites.In the electroreduction of CO_(2),the coexistence of Ni SAs and NPs strengthened the CO_(2)activation and the affinity towards the key intermediate of*COOH,lowering the free energy for the potential-determining*CO_(2)→*COOH step,and therefore promoted the catalysis efficiency.
文摘A nine-year-old girl with Staphylococcus epidermidis meningitis combined with acute disseminated encephalomyelitis （ADEM） was enrolled in the present study, and exhibited sustained fever and headache for 5 days and a single seizure episode. Meningeal irritation and disturbance of consciousness were apparent. Cerebrospinal fluid examination revealed increased protein level and pleocytosis. Cerebrospinal fluid culture demonstrated Staphylococcus epidermidis growth. The patient was treated with intravenous cefotaxime, intravenous dexamethasone, and decreasing intracranial pressure for 3 weeks. Seizures and fever symptoms improved, but disturbance of consciousness, muscle weakness, and bilateral limb paresis were significant. IgG index was elevated and oligoclonal bands were positive in the cerebrospinal fluid. Magnetic resonance imaging demonstrated high T2-weighted signals in subcortical white matter, which were consistent with ADEM. High-dose methylprednisolone for 3 days and a 6-day pulse therapy with immunoglobulins resulted in improved clinical symptoms and cerebrospinal fluid examination. The patient＇s temperature dropped to normal, and the headache disappeared. A Staphylococcus epidermidis infection associated with ADEM is uncommon in children. Results suggested that Staphylococcus epidermidis infection could be a pathogenic factor for ADEM, and ADEM is a complication of Staphylococcus epidermidis meningitis.
基金supported by the National Natural Science Foundation of China Nos.11988101,12373012,and 12041302supported by CMS-CSST-2021A08 and CMS-CSST-2021-B02support from NSFC with grant No.12203064。
文摘Recent submillimeter dust thermal emission observations have unveiled a significant number of inter-arm massive molecular clouds in M31.However,the effectiveness of this technique is limited to its sensitivity,making it challenging to study more distant galaxies.This study introduces an alternative approach,utilizing optical extinctions derived from space-based telescopes,with a focus on the forthcoming China Space Station Telescope(CSST).We first demonstrate the capability of this method by constructing dust extinction maps for 17 inter-arm massive molecular clouds in M31 using the Panchromatic Hubble Andromeda Treasury data.Our analysis reveals that inter-arm massive molecular clouds with an optical extinction(A_(V)) greater than 1.6 mag exhibit a notable A_(V) excess,facilitating their identification.The majority of these inter-arm massive molecular clouds show an A_(V) around 1 mag,aligning with measurements from our JCMT data.Further validation using a mock CSST RGB star catalog confirms the method's effectiveness.We show that the derived A_(V)values using CSST z and y photometries align more closely with the input values.Molecular clouds with A_(V)> 1.6 mag can also be identified using the CSST mock data.We thus claim that future CSST observation clouds provide an effective way for the detection of inter-arm massive molecular clouds with significant optical extinction in nearby galaxies.
基金supported by the National Natural Science Foundation of China(Grant Nos.:92261203,21971106,22171073,22101118,and 22201123)the Central Guided Science and Technology Development Foundation of Liaoning Province,China(Grant No.:2022 JH6/100100036)+1 种基金the Start-up Fund from Southern University of Science and Technology(SUSTech),China,the Stable Support Plan Program of Shenzhen Natural Science Fund,China(Program Contract No.:20200925161141006)the Shenzhen Nobel Prize Scientists Laboratory Project(Shenzhen Grubbs Institute),China(Project No.:C17783101).
文摘Polyoxometalates(POMs)are molecular metal-oxide clusters with precise chemical composition and architecture.Besides their bioactivities,electron-rich POMs have shown potential for enhancing synergistic therapy,such as photothermal therapy(PTT),photodynamic therapy(PDT),and chemo-dynamic therapy(CDT),through near-infrared region(NIR)absorption and redox reactions.
基金supported by the National Natural Science Foundation of China (22178162, 22108116, 22072065, and 22222806)the Distinguished Youth Foundation of Jiangsu Province (BK20220053)+2 种基金the Six talent peaks project in Jiangsu Province (JNHB035)Natural Science Foundation of Jiangsu Province (BK20200688)State Key Laboratory of Materials-Oriented Chemical Engineering-Open Fund (KL20-07)。
文摘N-alkylation of amines with alcohols is a promising green route for the synthesis of N-alkylamines, but the designation of highly active and stable heterogeneous catalysts remains one challenge. In this work, we initiated the application of zeolite-encapsulated noble metal nanoparticles(NPs) in the N-alkylation of amines with aromatic alcohols. Platinum(Pt) NPs were directly confined into the framework of BEA zeolite with tunable Si/Al molar ratios and Na^(+) contents. The champion catalyst afforded the extremely high turnover number(TON) of 6,176 and turnover frequency(TOF) of 3,390 h^(-1) plus stable recyclability and broad substrate compatibility. The Na ions modulated the electronic state of Pt NPs to reach a moderate Pt–H strength, which wellbalanced the two crucial steps of dehydrogenation and H-transfer and accounted for the high catalytic performance. The encapsulation of zeolites provided spatial satisfaction for the synergy effect above and enhanced the stabilization of Pt NPs.
基金National Natural Science Foundation of China,Grant/Award Number:51577045。
文摘The authors investigate the effects of nanofillers with varying band‐gap energies on the space charge properties,breakdown field strength,and bulk resistivity of epoxy(EP)‐based composites.Additionally,the molecular orbital distribution of both the epoxy resin and nanofillers were examined through density functional theory.Experimental results indicate that the space charge accumulation within silicon dioxide/EP and germanium oxide/EP is reduced,leading to a more uniformly distributed electric field intensity within the specimen when compared to epoxy.As a result,both materials exhibit improved AC breakdown field strength and volume resistivity.Conversely,the amount of charge accumulated within tin dioxide/EP is higher,resulting in lower breakdown field strength than epoxy.The lowest unoccupied molecular orbital and the highest occupied molecular orbital energy level differences between epoxy and nanofillers introduce electron traps and hole traps at the interface,forming interfacial traps that affect the space charge distribution within the specimen,as well as the trap energy levels within the material.From the experimental results,shallow traps promote space charge accumulation and reduce the breakdown field strength,while deep traps have the opposite effect.
文摘Although cesium lead halide perovskite(CsPbX3,X=Cl,Br,or I)nanocrystals(PNCs)have been rapidly developed for multiple optoelectronic applications due to their outstanding optical and transport properties,their device fabrication and commercialization have been limited by their low structural stability,especially under environmental conditions.In this work,a new approach has been developed to protect the surface of these nanocrystals,which results in enhanced chemical stability and optical properties.This method is based on the encapsulation of CsPbX3 NCs into a polyimide with intrinsic microporosity(PIM-PI),4,4′-(hexafluoroisopropylidene)diphthalic anhydride reacted with 2,4,6-trimethyl-m-phenylenediamine(6FDATrMPD).The presence of 6FDA-TrMPD as a protective layer can efficiently isolate NCs from an air environment and subsequently enhance their optical and photoluminescence stability.More specifically,comparing NCs treated with a polymer to as-synthesized nanocrystals after 168 h,we observe that the PL intensity decreased by 70%and 20%for the NCs before and after polymer treatment.In addition,the PNC film with a polymer shows a much longer excited-state lifetime than the as-synthesized nanocrystals,indicating that the surface trap states are significantly reduced in the treated PNCs.The enhancement in chemical and air stability,as well as optical behavior,will further improve the performance of CsPbBr3 PNCs yielding promising optical devices and paving the way for their production and implementation at a large scale.
