Acoustic detection has many applications across science and technology from medicine to imaging and communications.However,most acoustic sensors have a common limitation in that the detection must be near the acoustic...Acoustic detection has many applications across science and technology from medicine to imaging and communications.However,most acoustic sensors have a common limitation in that the detection must be near the acoustic source.Alternatively,laser interferometry with picometer-scale motional displacement detection can rapidly and precisely measure sound-induced minute vibrations on remote surfaces.Here,we demonstrate the feasibility of sound detection up to 100 kHz at remote sites with≈60 m optical path length via laser homodyne interferometry.Based on our ultrastable hertz linewidth laser with 10-15 fractional stability,our laser interferometer achieves 0.5 pm/Hz1/2 displacement sensitivity near 10 kHz,bounded only by laser frequency noise over 10 kHz.Between 140 Hz and 15 kHz,we achieve a homodyne acoustic sensing sensitivity of subnanometer/Pascal across our conversational frequency overtones.The minimal sound pressure detectable over 60 m optical path length is≈2 mPa,with dynamic ranges over 100 dB.With the demonstrated standoff picometric distance metrology,we successfully detected and reconstructed musical scores of normal conversational volumes with high fidelity.The acoustic detection via this precision laser interferometer could be applied to selective area sound sensing for remote acoustic metrology,optomechanical vibrational motion sensing,and ultrasensitive optical microphones at the laser frequency noise limits.展开更多
Ultrastable metallic glasses(SMGs)exhibit enhanced stability comparable to those of conventional glasses aged for thousands of years.The ability to understand why certain alloy compositions and processing conditions g...Ultrastable metallic glasses(SMGs)exhibit enhanced stability comparable to those of conventional glasses aged for thousands of years.The ability to understand why certain alloy compositions and processing conditions generate an SMG is an emerging challenge.Herein,amplitude-modulation dynamic atomic force microscopy was utilized for tracking the structure of Zr_(50)Cu_(50),Zr_(50)Cu_(44.5)Al_(5.5)and Zr_(50)Cu_(41.5)Al_(5.5)Mo_(3) thin film metallic glasses(TFMGs)that were produced by direct current magnetron sputtering at room temperature with the rate of deposition being the only variable.The transition in stability from bulkto SMG-like behavior resides in the change of relaxation mechanism as the deposition rate is decreased.The formation of SMGs is directly linked with the degree of structural heterogeneity,whereby MGs with greater heterogeneity have a higher potential to form SMGs with more significant enhancement in stability.Slower deposition rates,however,are required to yield the more homogenous structure and lower energy state underlying the ultrastability.Ultrastability is closely linked with the geometric shape and distribution of loosely packed phases,whereby SMGs containing more slender loosely packed phases with a more skewed distribution achieve more significant improvements in stability.This work not only provides direct evidence of the structure of SMGs,but also opens new horizons for the design of SMGs.展开更多
Lithium-sulfur batteries(LSBs)can work at high temperatures,but they suffer from poor cycle life stability due to the“shuttle effect”of polysulfides.In this study,pollen-derived porous carbon/cuprous phosphide(PC/Cu...Lithium-sulfur batteries(LSBs)can work at high temperatures,but they suffer from poor cycle life stability due to the“shuttle effect”of polysulfides.In this study,pollen-derived porous carbon/cuprous phosphide(PC/Cu_(3)P)hybrids were rationally synthesized using a one-step carbonization method using pollen as the source material,acting as the sulfur host for LSBs.In the hybrid,polar Cu_(3)P can markedly inhibit the“shuttle effect”by regulating the adsorption ability toward polysulfides,as confirmed by theoretical calculations and experimental tests.As an example,the camellia pollen porous carbon(CPC)/Cu_(3)P/S electrode shows a high capacity of 1205.6 mAh g^(−1) at 0.1 C,an ultralow capacity decay rate of 0.038%per cycle after 1000 cycles at 1 C,and a rather high initial Coulombic efficiency of 98.5%.The CPC/Cu_(3)P LSBs can work well at high temperatures,having a high capacity of 545.9 mAh g^(−1) at 1 C even at 150℃.The strategy of the PC/Cu_(3)P hybrid proposed in this study is expected to be an ideal cathode for ultrastable high-temperature LSBs.We believe that this strategy is universal and worthy of in-depth development for the next generation energy storage devices.展开更多
Background:Ocular therapy administrated by ophthalmic drops is advantageous thanks to its simplicity.However,efficiency of active molecules is limited when administered by this method.Indeed,more than 99.9%is discarde...Background:Ocular therapy administrated by ophthalmic drops is advantageous thanks to its simplicity.However,efficiency of active molecules is limited when administered by this method.Indeed,more than 99.9%is discarded due to multiple factors including lacrimal drainage.Low retention time of drugs at the cornea leads to their poor penetration.Our hypothesis is that a drug delivery system based on gold nanoparticles should enhance the efficiency of the drugs.The main objective is to develop new methods to improve active molecules biodisponibility in ocular therapy thanks to a new drug delivery system implying gold nanoparticles.The specific objectives are:(I)to synthesize and characterize ultrastable gold nanoparticles,(II)to establish the drug encapsulation protocol,(III)to develop a separation method of free and encapsulated drugs to allow their quantification,(IV)to study the cytotoxicity of our gold nanoparticles.Methods:Ultrastable gold nanoparticles were synthesized by a new method and their ultrastability toward several harsh conditions was characterized.An encapsulation protocol was settled for several drugs.The separation of free and encapsulated drugs was performed with magnetic beads.The quantification of the encapsulated drugs was performed by HPLC.A MTS assay was performed on 3 corneal epithelial cell populations,exposed or unexposed to gold nanoparticles.Reconstructed corneas were prepared using the self-assembly method.A wound healing experience was performed on those corneas with or without nanoparticles.Results:Gold nanoparticles were synthesized and purified according to our new experimental conditions.They support harsh conditions as several cycles of freeze-drying,heating,salt exposition and ultracentrifugation.For the first time in literature,gold nanoparticle support autoclave sterilisation.The separation method involving magnetic beads was optimized to get rid of non-specific interactions.The encapsulation efficiency varies according to the active molecule.The MTS assay did not show diminution of the cellular viability when in presence of gold nanoparticles.Furthermore,gold nanoparticle exposition did not slow the wound healing of reconstructed corneas.Conclusions:Our new ultrastable gold nanoparticles can have a major impact in nanomedicine.They can support harsh conditions,as autoclave treatment,allowing their sterilisation for in vivo use.We showed that active molecules can be encapsulated in gold nanoparticles.In addition,they do not seem to cause any diminution of cellular viability.These data suggest the possible improvements in ocular therapy thanks to gold nanoparticles.展开更多
Sodium-ion batteries hold significant potential for large-scale energy storage applications,primarily because of their impressive energy density.Massive researches on anode materials mainly focus on carbon materials b...Sodium-ion batteries hold significant potential for large-scale energy storage applications,primarily because of their impressive energy density.Massive researches on anode materials mainly focus on carbon materials because of their high theoretical capacity and affordability.Nevertheless,the large volume change of carbon materials during the sodium ion intercalation/de-intercalation processes seriously influences their electrochemical properties and limits their practical applications.Finding stable and high performance materials remains a significant challenge in the progress of NIBs development.Herein,a pyrochlore-type oxide(A_(2)B_(2)O_(7))for sodium storage is successfully synthesized in this work,which adopts a“zigzag”structure of AO_(6) octahedra and BO_(4) tetrahedra.Density functional theory calculations and structural characterizations indicate that the material is able to host Na ions in the structure properly and maintains excellent structural stability during the intercalation and deintercalation of Na^(+),making the pyrochlore-type oxide an excellent Na storage material.Electrochemical measurements indicate that the pyrochlore-type oxide exhibits excellent electrochemical performances and extremely stable sodium storage ability(high capacity of~250 mAh g^(-1)at 30 mA g^(-1),~85% capacity retention after 25000 cycles at 5 A g^(-1)).In addition,the full cell shows excellent electrochemical performances in all climatic operation temperature ranges from-30℃ to 40℃(117 mAh g^(-1)at 40℃ and 103 mAh g^(-1)at-30℃).The high reversible capacity,impressive rate capability and outstanding cycling stability demonstrated by pyrochlore-type oxides make them a competitive choice among Na-ion anode materials.This study introduces a new type of pyrochlore-type transition metal oxide for stable Na storage,which shows high capacity,excellent rate performances and extremely long cycling life.This study is expected to significantly advance the development of anode for NIBs.展开更多
Photoelectrochemical(PEC)photodetectors(PDs)enabling high sensitivity/stability and self-powered operation in undersea weak-light environments is significant to the development of underwater optical communication(UOC)...Photoelectrochemical(PEC)photodetectors(PDs)enabling high sensitivity/stability and self-powered operation in undersea weak-light environments is significant to the development of underwater optical communication(UOC)application.However,to date,the UOC system based on weak light-driven PEC PDs has rarely been investigated,primarily due to the lack of functional material and relevant heterojunction photoelectrodes with efficient weak light harvesting,fast response time and high stability.Herein,we introduced the Al doping in colloidal CuInS2(CIS)quantum dots(QDs)to suppress the non-radiative recombination and induce the self-oxidation Al2O3 protective layer for largely enhanced photo-/chemical stability.The prepared Al-doped CIS QDs were used to decorate BiVO4(BVO)as photoelectrodes for the fabrication of PEC PD devices,which delivered a maximum responsivity of 1 A·W^(−1),a detectivity of 1.02×10^(12)Jones,fast response time(26/25 ms)and ultrastable long-term stability(performance nearly unchanged after 36-hour stability test),thus demonstrating the UOC application even under a weak-light intensity of 0.14 mW·cm^(−2).The results manifest the potential of rationally designed QDs/metal oxide photoelectrode to achieve highly efficient and stable PEC PDs for next-generation weak-light UOC applications.展开更多
Metal sulfides are emerging highly active electrocatalysts for the oxygen evolution reaction(OER),but still suffer from the instability caused by their inevitable reconstruction,especially at industrial-level current ...Metal sulfides are emerging highly active electrocatalysts for the oxygen evolution reaction(OER),but still suffer from the instability caused by their inevitable reconstruction,especially at industrial-level current density.Here,it is discovered that Fe-incorporated Ni3S2 nanowires can deliver extraordinary durability with an ultralow potential degradation rate of 0.006 mV/h in alkaline electrolytes made with fresh water and seawater at a benchmark of 500 mA cm^(-2) while meeting the industrial activity requirement for overpotential less than 300 mV(290 mV).Systematic experiments and theoretical simulations suggest that after forming the S-doped NiFeOOH shell to boost intrinsic activity,Fe incorporation effectivelymitigates the reconstruction of the Ni_(3)S_(2) nanowire core by restraining Ni oxidation and S dissolution,justifying the performance.This work highlights the significance of circumventing reconstruction and provides a strategy to explore practical chalcogenides-based OER electrocatalysts.展开更多
We demonstrate an ultrastable miniaturized transportable laser system at 1550 nm by locking it to an optical fiber delay line[FDL].To achieve optimized long-term frequency stability,the FDL was placed into a vacuum ch...We demonstrate an ultrastable miniaturized transportable laser system at 1550 nm by locking it to an optical fiber delay line[FDL].To achieve optimized long-term frequency stability,the FDL was placed into a vacuum chamber with a five-layer thermal shield,and a delicate two-stage active temperature stabilization,an optical power stabilization,and an RF power stabilization were applied in the system.A fractional frequency stability of better than 3.2×10^[-15]at 1 s averaging time and1.1×10^[-14]at 1000 s averaging time was achieved,which is the best long-term frequency stability of an all-fiber-based ultrastable laser observed to date.展开更多
Lead halide perovskite materials exhibit excellent scintillation performance,which,however,suffer from serious stability and toxicity problems.In contrast,the heavy metal-free anti-perovskite materials[MX_(4)]XA_(3)(A...Lead halide perovskite materials exhibit excellent scintillation performance,which,however,suffer from serious stability and toxicity problems.In contrast,the heavy metal-free anti-perovskite materials[MX_(4)]XA_(3)(A=alkali metal;M=transition metal;X=Cl,Br,I),a class of electron-inverted perovskite derivatives,exhibit robust structural and photophysical stability.Here,we design and prepare a lead-free[MnBr_(4)]BrCs_(3) anti-perovskite nanocrystal(NC)-embedded glass for efficient X-ray-excited luminescence with high-resolution X-ray imaging with a spatial resolution of 19.1 Ip mm^(-1).Due to the unique crystal structure and the protection of the glass matrix,the Cs_(3)MnBr_(5) NC-embedded glass exhibits excellent X-ray irradiation stability,thermal stability,and water resistance.These merits enable the demonstration of real-time and durable X-ray radiography based on the developed glassy composite.This work could stimulate the research and development of novel metal halide anti-perovskite materials and open a new path for future development in the field of high-resolution and ultrastable X-ray imaging.展开更多
The crystalline sponge method is a pragmatic and promising strategy for molecular structure determination.However,the dominant metal-organic framework crystal sponge platforms always face poor chemical stability,espec...The crystalline sponge method is a pragmatic and promising strategy for molecular structure determination.However,the dominant metal-organic framework crystal sponge platforms always face poor chemical stability,especially solvent instability,hampering their application in a vaster domain.Herein,we report an ultrastable π-π stacked porous organic molecular framework which exhibits permanent porosity,high thermal stability,and good chemical resistance.It can efficiently implement an approach to molecular structure determination via a single-crystal-to-single-crystal transformation.This is the first example utilizing π-π stacked porous organic molecular framework as“crystalline sponge”to determine a wide variety of vips,ranging from hydrophilic to hydrophobic,and from aliphatic to aromatic,which complements the crystalline sponges based on the famous metal-organic frameworks.More importantly,it can achieve rapid structure determination of small molecules within 3 h.展开更多
We demonstrate a proposal for making an ultrastable laser referenced to a multi-cavity, enabling a lower thermal noise limit due to the averaging effect. In comparison with a single-cavity system, relative frequency i...We demonstrate a proposal for making an ultrastable laser referenced to a multi-cavity, enabling a lower thermal noise limit due to the averaging effect. In comparison with a single-cavity system, relative frequency instability of the synthesized laser can be improved by a factor of the square root of the cavity number. We perform an experiment to simulate a two-cavity system with two independent ultrastable lasers. Experimental results show that the relative frequency instability(Allan deviation) of the synthesized laser is 5 × 10^(-16), improved by a factor of √2 from a single-cavity-stabilized laser.展开更多
Metal-organic frameworks(MOFs)are attractive for promising applications but plagued by difficult recovery and deployment due to their intrinsic nano/micro powder nature.Although significant efforts have been made to d...Metal-organic frameworks(MOFs)are attractive for promising applications but plagued by difficult recovery and deployment due to their intrinsic nano/micro powder nature.Although significant efforts have been made to develop separable solid matrixes for MOF supporting,the poor loading stability and durability of MOFs still challenge their engineering applications.Here,we present a facile and effective approach to fabricate MOF-based melamine foams(MFs)(denoted as MOFiths)with ultrahigh loading stability and operation stability,easy separation,and high-efficient performance for versatile robust applications.By adopting our approach,numbers of typical fragile MOFs characterized with wide ranges of particle size(from~nm to~μm)can be precisely incorporated into MFs with controllable loading ratios(up to~1,600%).Particularly,the produced MOFiths show excellent capacities for the highly effective and durable water purifications and acetalization reactions.100%of organic pollutants can be rapidly destructed within 10 min by MOFiths initiated Fenton or catalytic ozonation processes under five successive cycles while the maximum adsorption capacity of MOFiths toward Pb(II),Cd(II),and Cu(II)reaches to 422,222,and 105 mg·g^(-1),respectively.This study provides a critical solution to substantially facilitate the engineering applications of MOFs for long-term use in practice.展开更多
A single-Rh-site catalyst(Rh-TPISP)that was ionically-embedded on a P(V)quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation.The[Rh(CO)I_(3)]^(2-)unit was proposed to be the acti...A single-Rh-site catalyst(Rh-TPISP)that was ionically-embedded on a P(V)quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation.The[Rh(CO)I_(3)]^(2-)unit was proposed to be the active center of Rh-TPISP for the carbonylation reaction based on detailed Rh L3-edge X-ray absorption near edge structure(XANES),X-ray photoelectron spectroscopy(XPS),and Rh extended X-ray absorption fine structure(EXAFS)analyses.As the highlight of this study,Rh-TPISP displayed distinctly higher activity for heterogeneous ethanol carbonylation than the reported catalytic systems in which[Rh(CO)_(2)I_(2)]^(-)is the traditional active center.A TOF of 350 h^(-1)was obtained for the reaction over[Rh(CO)I_(3)]^(2-),with>95%propionyl selectivity at 3.5 MPa and 468 K.No deactivation was detected during a near 1000 h running test.The more electron-rich Rh center was thought to be crucial for explaining the superior activity and selectivity of Rh-TPISP,and the formation of two ionic bonds between[Rh(CO)I_(3)]^(2-)and the cationic P(V)framework([P]^(+))of the polymer was suggested to play a key role in firmly immobilizing the active species to prevent Rh leaching.展开更多
The asymmetric photocatalytic organic synthesis(APOS)process is a sustainable and environmentally benign method for the production of optically active chemicals with sunlight as an energy source.However,it still lacks...The asymmetric photocatalytic organic synthesis(APOS)process is a sustainable and environmentally benign method for the production of optically active chemicals with sunlight as an energy source.However,it still lacks efficient semiconductors with tunable band structures and has a low recycling stability.Herein,we report the synthesis of tetrahydroquinoline-linked covalent organic frameworks(QH-COFs)with irreversible tetrahydroquinoline linkage as efficient semiconductors for the visible-light-driven asymmetricα-alkylation of aldehydes by merging with a chiral secondary amine.Up to 94%ee was obtained over QH-COFs,and the activity of QH-COFs was significantly higher than those of inorganic semiconductors(e.g.,Ti O2,Bi VO4,and WO3)under similar conditions,which is mainly attributed to their narrow band gap and suitable band edge.As far as we know,QH-COFs are the most active semiconductors for asymmetricα-alkylation of aldehydes ever reported.The QH-COFs were prepared via a one-pot Povarov cascade imine formation and cycloaddition reaction using Sc(OTf)3/Yb(OTf)3 as Lewis acid catalysts.Attributed to the tetrahydroquinoline linkage,QH-COFs showed extremely high recycling stability,which made practicals application possible.This work not only opens up a new avenue for asymmetric photocatalysis but also provides an efficient and general method for the construction of robust COFs.展开更多
基金supported by the Office of Naval Research(Grant Nos.N00014-16-1-2094 and N00014-24-1-2547)the Lawrence Livermore National Laboratory(Grant No.B622827)the National Science Foundation.Y.-S.J.acknowledges support from KRISS(Grant Nos.25011026 and 25011211).
文摘Acoustic detection has many applications across science and technology from medicine to imaging and communications.However,most acoustic sensors have a common limitation in that the detection must be near the acoustic source.Alternatively,laser interferometry with picometer-scale motional displacement detection can rapidly and precisely measure sound-induced minute vibrations on remote surfaces.Here,we demonstrate the feasibility of sound detection up to 100 kHz at remote sites with≈60 m optical path length via laser homodyne interferometry.Based on our ultrastable hertz linewidth laser with 10-15 fractional stability,our laser interferometer achieves 0.5 pm/Hz1/2 displacement sensitivity near 10 kHz,bounded only by laser frequency noise over 10 kHz.Between 140 Hz and 15 kHz,we achieve a homodyne acoustic sensing sensitivity of subnanometer/Pascal across our conversational frequency overtones.The minimal sound pressure detectable over 60 m optical path length is≈2 mPa,with dynamic ranges over 100 dB.With the demonstrated standoff picometric distance metrology,we successfully detected and reconstructed musical scores of normal conversational volumes with high fidelity.The acoustic detection via this precision laser interferometer could be applied to selective area sound sensing for remote acoustic metrology,optomechanical vibrational motion sensing,and ultrasensitive optical microphones at the laser frequency noise limits.
文摘Ultrastable metallic glasses(SMGs)exhibit enhanced stability comparable to those of conventional glasses aged for thousands of years.The ability to understand why certain alloy compositions and processing conditions generate an SMG is an emerging challenge.Herein,amplitude-modulation dynamic atomic force microscopy was utilized for tracking the structure of Zr_(50)Cu_(50),Zr_(50)Cu_(44.5)Al_(5.5)and Zr_(50)Cu_(41.5)Al_(5.5)Mo_(3) thin film metallic glasses(TFMGs)that were produced by direct current magnetron sputtering at room temperature with the rate of deposition being the only variable.The transition in stability from bulkto SMG-like behavior resides in the change of relaxation mechanism as the deposition rate is decreased.The formation of SMGs is directly linked with the degree of structural heterogeneity,whereby MGs with greater heterogeneity have a higher potential to form SMGs with more significant enhancement in stability.Slower deposition rates,however,are required to yield the more homogenous structure and lower energy state underlying the ultrastability.Ultrastability is closely linked with the geometric shape and distribution of loosely packed phases,whereby SMGs containing more slender loosely packed phases with a more skewed distribution achieve more significant improvements in stability.This work not only provides direct evidence of the structure of SMGs,but also opens new horizons for the design of SMGs.
基金supported by the Innovation Platform of Energy Storage Engineering and New Material in Zhejiang University(No.K19-534202-002)the National Natural Science Foundation of China(No.21978261)the Zhejiang Provincial Key Research and Development Program of China(No.2021C01030).
文摘Lithium-sulfur batteries(LSBs)can work at high temperatures,but they suffer from poor cycle life stability due to the“shuttle effect”of polysulfides.In this study,pollen-derived porous carbon/cuprous phosphide(PC/Cu_(3)P)hybrids were rationally synthesized using a one-step carbonization method using pollen as the source material,acting as the sulfur host for LSBs.In the hybrid,polar Cu_(3)P can markedly inhibit the“shuttle effect”by regulating the adsorption ability toward polysulfides,as confirmed by theoretical calculations and experimental tests.As an example,the camellia pollen porous carbon(CPC)/Cu_(3)P/S electrode shows a high capacity of 1205.6 mAh g^(−1) at 0.1 C,an ultralow capacity decay rate of 0.038%per cycle after 1000 cycles at 1 C,and a rather high initial Coulombic efficiency of 98.5%.The CPC/Cu_(3)P LSBs can work well at high temperatures,having a high capacity of 545.9 mAh g^(−1) at 1 C even at 150℃.The strategy of the PC/Cu_(3)P hybrid proposed in this study is expected to be an ideal cathode for ultrastable high-temperature LSBs.We believe that this strategy is universal and worthy of in-depth development for the next generation energy storage devices.
文摘Background:Ocular therapy administrated by ophthalmic drops is advantageous thanks to its simplicity.However,efficiency of active molecules is limited when administered by this method.Indeed,more than 99.9%is discarded due to multiple factors including lacrimal drainage.Low retention time of drugs at the cornea leads to their poor penetration.Our hypothesis is that a drug delivery system based on gold nanoparticles should enhance the efficiency of the drugs.The main objective is to develop new methods to improve active molecules biodisponibility in ocular therapy thanks to a new drug delivery system implying gold nanoparticles.The specific objectives are:(I)to synthesize and characterize ultrastable gold nanoparticles,(II)to establish the drug encapsulation protocol,(III)to develop a separation method of free and encapsulated drugs to allow their quantification,(IV)to study the cytotoxicity of our gold nanoparticles.Methods:Ultrastable gold nanoparticles were synthesized by a new method and their ultrastability toward several harsh conditions was characterized.An encapsulation protocol was settled for several drugs.The separation of free and encapsulated drugs was performed with magnetic beads.The quantification of the encapsulated drugs was performed by HPLC.A MTS assay was performed on 3 corneal epithelial cell populations,exposed or unexposed to gold nanoparticles.Reconstructed corneas were prepared using the self-assembly method.A wound healing experience was performed on those corneas with or without nanoparticles.Results:Gold nanoparticles were synthesized and purified according to our new experimental conditions.They support harsh conditions as several cycles of freeze-drying,heating,salt exposition and ultracentrifugation.For the first time in literature,gold nanoparticle support autoclave sterilisation.The separation method involving magnetic beads was optimized to get rid of non-specific interactions.The encapsulation efficiency varies according to the active molecule.The MTS assay did not show diminution of the cellular viability when in presence of gold nanoparticles.Furthermore,gold nanoparticle exposition did not slow the wound healing of reconstructed corneas.Conclusions:Our new ultrastable gold nanoparticles can have a major impact in nanomedicine.They can support harsh conditions,as autoclave treatment,allowing their sterilisation for in vivo use.We showed that active molecules can be encapsulated in gold nanoparticles.In addition,they do not seem to cause any diminution of cellular viability.These data suggest the possible improvements in ocular therapy thanks to gold nanoparticles.
文摘Sodium-ion batteries hold significant potential for large-scale energy storage applications,primarily because of their impressive energy density.Massive researches on anode materials mainly focus on carbon materials because of their high theoretical capacity and affordability.Nevertheless,the large volume change of carbon materials during the sodium ion intercalation/de-intercalation processes seriously influences their electrochemical properties and limits their practical applications.Finding stable and high performance materials remains a significant challenge in the progress of NIBs development.Herein,a pyrochlore-type oxide(A_(2)B_(2)O_(7))for sodium storage is successfully synthesized in this work,which adopts a“zigzag”structure of AO_(6) octahedra and BO_(4) tetrahedra.Density functional theory calculations and structural characterizations indicate that the material is able to host Na ions in the structure properly and maintains excellent structural stability during the intercalation and deintercalation of Na^(+),making the pyrochlore-type oxide an excellent Na storage material.Electrochemical measurements indicate that the pyrochlore-type oxide exhibits excellent electrochemical performances and extremely stable sodium storage ability(high capacity of~250 mAh g^(-1)at 30 mA g^(-1),~85% capacity retention after 25000 cycles at 5 A g^(-1)).In addition,the full cell shows excellent electrochemical performances in all climatic operation temperature ranges from-30℃ to 40℃(117 mAh g^(-1)at 40℃ and 103 mAh g^(-1)at-30℃).The high reversible capacity,impressive rate capability and outstanding cycling stability demonstrated by pyrochlore-type oxides make them a competitive choice among Na-ion anode materials.This study introduces a new type of pyrochlore-type transition metal oxide for stable Na storage,which shows high capacity,excellent rate performances and extremely long cycling life.This study is expected to significantly advance the development of anode for NIBs.
基金support from the Sichuan Science and Technology Program(No.2024JDRC0057)the Yunnan Key Laboratory of Electromagnetic Materials and Devices,Yunnan University(No.ZZ2024001)+1 种基金the support from the Sichuan Science and Technology Program(No.2023NSFSC0461)A.I.C.acknowledges the support from the National Natural Science Foundation of China(No.W2433035).
文摘Photoelectrochemical(PEC)photodetectors(PDs)enabling high sensitivity/stability and self-powered operation in undersea weak-light environments is significant to the development of underwater optical communication(UOC)application.However,to date,the UOC system based on weak light-driven PEC PDs has rarely been investigated,primarily due to the lack of functional material and relevant heterojunction photoelectrodes with efficient weak light harvesting,fast response time and high stability.Herein,we introduced the Al doping in colloidal CuInS2(CIS)quantum dots(QDs)to suppress the non-radiative recombination and induce the self-oxidation Al2O3 protective layer for largely enhanced photo-/chemical stability.The prepared Al-doped CIS QDs were used to decorate BiVO4(BVO)as photoelectrodes for the fabrication of PEC PD devices,which delivered a maximum responsivity of 1 A·W^(−1),a detectivity of 1.02×10^(12)Jones,fast response time(26/25 ms)and ultrastable long-term stability(performance nearly unchanged after 36-hour stability test),thus demonstrating the UOC application even under a weak-light intensity of 0.14 mW·cm^(−2).The results manifest the potential of rationally designed QDs/metal oxide photoelectrode to achieve highly efficient and stable PEC PDs for next-generation weak-light UOC applications.
基金the National Key Research and Development Program of China(grant no.2021YFA1501002)National Natural Science Foundation of China(grant nos.22025208,22075300,and 21902162)+1 种基金DNL Cooperation Fund,CAS(grant no.DNL202008)Chinese Academy of Sciences,and Australian Research Council(grant no.DE220100746).
文摘Metal sulfides are emerging highly active electrocatalysts for the oxygen evolution reaction(OER),but still suffer from the instability caused by their inevitable reconstruction,especially at industrial-level current density.Here,it is discovered that Fe-incorporated Ni3S2 nanowires can deliver extraordinary durability with an ultralow potential degradation rate of 0.006 mV/h in alkaline electrolytes made with fresh water and seawater at a benchmark of 500 mA cm^(-2) while meeting the industrial activity requirement for overpotential less than 300 mV(290 mV).Systematic experiments and theoretical simulations suggest that after forming the S-doped NiFeOOH shell to boost intrinsic activity,Fe incorporation effectivelymitigates the reconstruction of the Ni_(3)S_(2) nanowire core by restraining Ni oxidation and S dissolution,justifying the performance.This work highlights the significance of circumventing reconstruction and provides a strategy to explore practical chalcogenides-based OER electrocatalysts.
基金supported by the Special Foundation for State Major Basic Research Program of China(Nos.2021YFC2201803 and 2021YFC2201904)。
文摘We demonstrate an ultrastable miniaturized transportable laser system at 1550 nm by locking it to an optical fiber delay line[FDL].To achieve optimized long-term frequency stability,the FDL was placed into a vacuum chamber with a five-layer thermal shield,and a delicate two-stage active temperature stabilization,an optical power stabilization,and an RF power stabilization were applied in the system.A fractional frequency stability of better than 3.2×10^[-15]at 1 s averaging time and1.1×10^[-14]at 1000 s averaging time was achieved,which is the best long-term frequency stability of an all-fiber-based ultrastable laser observed to date.
基金financially supported by the National Natural Science Foundation of China (62122027, 52002128, 62075063, 62205109, 12204179, 52202004)Key R&D Program of Guangzhou (202007020003)+6 种基金fellowship of the China Postdoctoral Science Foundation (2022M711185, 2021M691054)National Postdoctoral Program for Innovative Talents of China (BX20220113)Guangdong Basic and Applied Basic Research Foundation (2021A1515110911, 2021A1515110475, 2022A1515011289, 2023A1515012666)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01X137)Fundamental Research Funds for the Central Universities (2022ZYGXZR030)Guangzhou Basic and Applied Basic Research Foundation (202201010428)State Key Laboratory of Luminescent Materials and Devices, South China University of Technology
文摘Lead halide perovskite materials exhibit excellent scintillation performance,which,however,suffer from serious stability and toxicity problems.In contrast,the heavy metal-free anti-perovskite materials[MX_(4)]XA_(3)(A=alkali metal;M=transition metal;X=Cl,Br,I),a class of electron-inverted perovskite derivatives,exhibit robust structural and photophysical stability.Here,we design and prepare a lead-free[MnBr_(4)]BrCs_(3) anti-perovskite nanocrystal(NC)-embedded glass for efficient X-ray-excited luminescence with high-resolution X-ray imaging with a spatial resolution of 19.1 Ip mm^(-1).Due to the unique crystal structure and the protection of the glass matrix,the Cs_(3)MnBr_(5) NC-embedded glass exhibits excellent X-ray irradiation stability,thermal stability,and water resistance.These merits enable the demonstration of real-time and durable X-ray radiography based on the developed glassy composite.This work could stimulate the research and development of novel metal halide anti-perovskite materials and open a new path for future development in the field of high-resolution and ultrastable X-ray imaging.
基金supported by the National Nature Science Foundation of China(grant nos.21871266,21731006,and 21403241)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDB20000000)+1 种基金Key Research Program of Frontier Science CAS(grant no.QYZDY-SSW-SLH025)Youth Innovation Promotion Association CAS.
文摘The crystalline sponge method is a pragmatic and promising strategy for molecular structure determination.However,the dominant metal-organic framework crystal sponge platforms always face poor chemical stability,especially solvent instability,hampering their application in a vaster domain.Herein,we report an ultrastable π-π stacked porous organic molecular framework which exhibits permanent porosity,high thermal stability,and good chemical resistance.It can efficiently implement an approach to molecular structure determination via a single-crystal-to-single-crystal transformation.This is the first example utilizing π-π stacked porous organic molecular framework as“crystalline sponge”to determine a wide variety of vips,ranging from hydrophilic to hydrophobic,and from aliphatic to aromatic,which complements the crystalline sponges based on the famous metal-organic frameworks.More importantly,it can achieve rapid structure determination of small molecules within 3 h.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.91536217and 91336101)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2015334)the Special Funds for Scientific Equipment Development(No.YZ201518) from the Chinese Academy of Sciences for the use of the developed equipment
文摘We demonstrate a proposal for making an ultrastable laser referenced to a multi-cavity, enabling a lower thermal noise limit due to the averaging effect. In comparison with a single-cavity system, relative frequency instability of the synthesized laser can be improved by a factor of the square root of the cavity number. We perform an experiment to simulate a two-cavity system with two independent ultrastable lasers. Experimental results show that the relative frequency instability(Allan deviation) of the synthesized laser is 5 × 10^(-16), improved by a factor of √2 from a single-cavity-stabilized laser.
基金This work was supported by the National Natural Science Foundation of China(No.22106141)the Key Research and Development Program of Zhejiang Province(No.2018C03004)+1 种基金the Scientific Launching Funding of Zhejiang Sci-Tech University and the Postdoctoral Program(No.TYY202103)of Zhejiang Sci-Tech University Tongxiang Research InstituteThe authors also acknowledge the support by the Brook Byers Institute for Sustainable Systems,Hightower Chair and the Georgia Research Alliance at the Georgia Institute of Technology.The views and ideas expressed herein are solely those of the authors’and do not represent the ideas of the funding agencies in any form。
文摘Metal-organic frameworks(MOFs)are attractive for promising applications but plagued by difficult recovery and deployment due to their intrinsic nano/micro powder nature.Although significant efforts have been made to develop separable solid matrixes for MOF supporting,the poor loading stability and durability of MOFs still challenge their engineering applications.Here,we present a facile and effective approach to fabricate MOF-based melamine foams(MFs)(denoted as MOFiths)with ultrahigh loading stability and operation stability,easy separation,and high-efficient performance for versatile robust applications.By adopting our approach,numbers of typical fragile MOFs characterized with wide ranges of particle size(from~nm to~μm)can be precisely incorporated into MFs with controllable loading ratios(up to~1,600%).Particularly,the produced MOFiths show excellent capacities for the highly effective and durable water purifications and acetalization reactions.100%of organic pollutants can be rapidly destructed within 10 min by MOFiths initiated Fenton or catalytic ozonation processes under five successive cycles while the maximum adsorption capacity of MOFiths toward Pb(II),Cd(II),and Cu(II)reaches to 422,222,and 105 mg·g^(-1),respectively.This study provides a critical solution to substantially facilitate the engineering applications of MOFs for long-term use in practice.
文摘A single-Rh-site catalyst(Rh-TPISP)that was ionically-embedded on a P(V)quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation.The[Rh(CO)I_(3)]^(2-)unit was proposed to be the active center of Rh-TPISP for the carbonylation reaction based on detailed Rh L3-edge X-ray absorption near edge structure(XANES),X-ray photoelectron spectroscopy(XPS),and Rh extended X-ray absorption fine structure(EXAFS)analyses.As the highlight of this study,Rh-TPISP displayed distinctly higher activity for heterogeneous ethanol carbonylation than the reported catalytic systems in which[Rh(CO)_(2)I_(2)]^(-)is the traditional active center.A TOF of 350 h^(-1)was obtained for the reaction over[Rh(CO)I_(3)]^(2-),with>95%propionyl selectivity at 3.5 MPa and 468 K.No deactivation was detected during a near 1000 h running test.The more electron-rich Rh center was thought to be crucial for explaining the superior activity and selectivity of Rh-TPISP,and the formation of two ionic bonds between[Rh(CO)I_(3)]^(2-)and the cationic P(V)framework([P]^(+))of the polymer was suggested to play a key role in firmly immobilizing the active species to prevent Rh leaching.
文摘The asymmetric photocatalytic organic synthesis(APOS)process is a sustainable and environmentally benign method for the production of optically active chemicals with sunlight as an energy source.However,it still lacks efficient semiconductors with tunable band structures and has a low recycling stability.Herein,we report the synthesis of tetrahydroquinoline-linked covalent organic frameworks(QH-COFs)with irreversible tetrahydroquinoline linkage as efficient semiconductors for the visible-light-driven asymmetricα-alkylation of aldehydes by merging with a chiral secondary amine.Up to 94%ee was obtained over QH-COFs,and the activity of QH-COFs was significantly higher than those of inorganic semiconductors(e.g.,Ti O2,Bi VO4,and WO3)under similar conditions,which is mainly attributed to their narrow band gap and suitable band edge.As far as we know,QH-COFs are the most active semiconductors for asymmetricα-alkylation of aldehydes ever reported.The QH-COFs were prepared via a one-pot Povarov cascade imine formation and cycloaddition reaction using Sc(OTf)3/Yb(OTf)3 as Lewis acid catalysts.Attributed to the tetrahydroquinoline linkage,QH-COFs showed extremely high recycling stability,which made practicals application possible.This work not only opens up a new avenue for asymmetric photocatalysis but also provides an efficient and general method for the construction of robust COFs.
