The scarcity,high cost and susceptibility to CO of Platinum severely restrict its application in alkaline hydrogen oxidation reaction(HOR).Hybridizing Pt with other transition metals provides an effective strategy to ...The scarcity,high cost and susceptibility to CO of Platinum severely restrict its application in alkaline hydrogen oxidation reaction(HOR).Hybridizing Pt with other transition metals provides an effective strategy to modulate its catalytic HOR performance,but at the cost of mass activity due to the coverage of modifiers on Pt surface.Herein,we constructed dual junctions'Pt/nitrogen-doped carbon(Pt/NC)andδ-MoC/NC to modify electronic structure of Pt via interfacial electron transfer to acquire Pt-MoC@NC catalyst with electron-deficient Pt nanoparticles,simultaneously endowing it with high mass activity and durability of alkaline HOR.Moreover,the unique structure of Pt-MoC@NC endows Pt with a high COtolerance at 1,000 ppm CO/H_(2),a quality that commercial Pt-C catalyst lacks.The theoretical calculations not only confirm the diffusion of electrons from Pt/NC to Mo C/NC could occur,but also demonstrate the negative shift of Pt d-band center for the optimized binding energies of*H,*OH and CO.展开更多
Emerging evidence shows that dietary oligosaccharides are important prebiotics that can improve intestinal flora,while dietary polyphenols can act directly on intestinal cells.However,information about their synergist...Emerging evidence shows that dietary oligosaccharides are important prebiotics that can improve intestinal flora,while dietary polyphenols can act directly on intestinal cells.However,information about their synergistic effects on gut health is still limited.In this study,alginate oligosaccharide(AOS)and cyanidin-3-O-glucoside(C3G)were selected as a common marine plant oligosaccharide and terrestrial plant polyphenol,respectively,to study their effects on intestinal health.The results show that,in comparison to their individual applications,the combination of AOS and C3G(mass ratio,3:1)displayed a stronger ability to up-regulate the expression of tight junction proteins,while enhanced intestinal epithelial barrier was also observed and levels of mucin-2 andβ-defensins were simultaneously increased in the intestinal mucus.Interestingly,the secretion of immunoglobulin A and immune-related cytokines were approximately doubled by the AOS+C3G mixture.In addition,the AOS+C3G mixture was found to be more conducive to the positive transformation of intestinal flora,which stimulated the growth of beneficial bacteria Akkermansia,Lachnospiraceae and Feacalibaculum while inhibiting the growth of harmful bacteria Helicobacter and Turicibacter.The data generated herein thus suggests that dietary oligosaccharides and dietary polyphenols may be more beneficial to intestinal health when applied in combination than their individual effects alone.展开更多
The stabilization problem of distributed proportional-integral-derivative(PID)controllers for general first-order multi-agent systems with time delay is investigated in the paper.The closed-loop multi-input multi-outp...The stabilization problem of distributed proportional-integral-derivative(PID)controllers for general first-order multi-agent systems with time delay is investigated in the paper.The closed-loop multi-input multi-output(MIMO)framework in frequency domain is firstly introduced for the multi-agent system.Based on the matrix theory,the whole system is decoupled into several subsystems with respect to the eigenvalues of the Laplacian matrix.Considering that the eigenvalues may be complex numbers,the consensus problem of the multi-agent system is transformed into the stabilizing problem of all the subsystems with complex coefficients.For each subsystem with complex coefficients,the range of admissible proportional gains is analytically determined.Then,the stabilizing region in the space of integral gain and derivative gain for a given proportional gain value is also obtained in an analytical form.The entire stabilizing set can be determined by sweeping proportional gain in the allowable range.The proposed method is conducted for general first-order multi-agent systems under arbitrary topology including undirected and directed graph topology.Besides,the results in the paper provide the basis for the design of distributed PID controllers satisfying different performance criteria.The simulation examples are presented to check the validity of the proposed control strategy.展开更多
Fluorescent carbon dots(CDs)have recently become a research hotspot in multidisciplinary fields owing to their distinctive advantages,including outstanding photoluminescence properties,high biocompatibility,low toxici...Fluorescent carbon dots(CDs)have recently become a research hotspot in multidisciplinary fields owing to their distinctive advantages,including outstanding photoluminescence properties,high biocompatibility,low toxicity,and abundant raw materials.Among the promising CDs,narrow‐bandwidth emissive CDs with high color purity have emerged as a rising star in recent years because of their significant potential applications in bioimaging,information sensing,and photoelectric displays.In this review,the state-of-the-art advances of narrow-bandwidth emissive CDs are systematically summarized,and the factors influencing the emission bandwidth,preparation methods,and applications of narrow-bandwidth emissive CDs are described in detail.Besides,existing challenges and future perspectives for achieving high-performance narrow-bandwidth emissive CDs are also discussed.This overview paper is expected to generate more interest and promote the rapid development of this significant research area.展开更多
125 μm-breath sensor with high sensitivity and rapid response was prepared by using n-type Si: Au material. Its sensitivity coefficient and time constant were 4 V.sec / L and 38 msec, respec-tively. Its working princ...125 μm-breath sensor with high sensitivity and rapid response was prepared by using n-type Si: Au material. Its sensitivity coefficient and time constant were 4 V.sec / L and 38 msec, respec-tively. Its working principle was based on ano- malous resistance effect, which not only increa- sed the sensitivity, but also reduced its time con-stant greatly. Its signal processing system can select the breath signals and work stably. Therefore, the small changes of breath system can be measured and, especially, patient’s breath rate can be monitored at a distance.展开更多
In-plane symmetry is an important contributor to the physical properties of two-dimensional layered materials, as well as atomically thin heterojunctions. Here, we demonstrate anisotropic/isotropic van der Waals （vdW...In-plane symmetry is an important contributor to the physical properties of two-dimensional layered materials, as well as atomically thin heterojunctions. Here, we demonstrate anisotropic/isotropic van der Waals （vdW） heterostructures of ReS2 and MoS2 monolayers, where interlayer coupling interactions and charge separation were observed by in situ Raman-photoluminescence spectroscopy, electrical, and photoelectrical measurements. We believe that these results could be helpful for understanding the fundamental physics of atomically thin vdW heterostructures and creating novel electronic and optoelectronic devices.展开更多
AgNO3 is often used in the preparation of Au nanostructures since Ag-based substances （AgBS） can selectively be adsorbed on Au（100） and significantly modulate the growth of Au nanocrystals. High-index-faceted Au n...AgNO3 is often used in the preparation of Au nanostructures since Ag-based substances （AgBS） can selectively be adsorbed on Au（100） and significantly modulate the growth of Au nanocrystals. High-index-faceted Au nanostructures have demonstrated excellent performance in catalysis and surface enhanced Raman scattering （SERS）, thus attracting the interest of many researchers in the past several decades. Herein, high-index-faceted Pd@Au concave nanocubes （CNCs） were prepared using AgBS as growth-directing agents in the heterogeneous growth of Au on Pd nanocubes （NCs）. During the growth of Pd@Au CNCs, Au atoms are initially deposited on the Pd{100} facets leading to the formation of thin Au shells, and then AgBS are quickly adsorbed on the formed Au（100）, favoring the growth along 〈111〉 and the formation of Pd@Au CNCs. Transmission electron microscopy （TEM）, high resolution transmission electron microscopy （HRTEM）, energy dispersive spectroscopy （EDS）, high angle annular dark field （HAADF）, and scanning transmission electron microscopy EDS （STEM- EDS） were used to systematically investigate the growth of Pd@Au CNCs. We also demonstrated that the high-index-faceted Pd@Au CNCs exhibited excellent SERS performances.展开更多
Two-dimensional(2D)WS2 offers great prospects for assembling next-generation optoelectronic and electronic devices due to its thickness-dependent optical and electronic properties.However,layer-number-controlled growt...Two-dimensional(2D)WS2 offers great prospects for assembling next-generation optoelectronic and electronic devices due to its thickness-dependent optical and electronic properties.However,layer-number-controlled growth of WS2 is still a challenge up to now.This work presents controlled growth of bilayer WS2 triangular flakes by carbon-nanoparticle-assisted chemical vapor deposition(CVD)process.The growth mechanism is also proposed.In addition,the field effect transistors(FETs)based on monolayer and bilayer WS2 are also fabricated and investigated.The bilayer FET displays a mobility of 34 cm2·V^-1·s^-1,much higher than that of the monolayer FET.The high figures of merit make bilayer WS2 a promising candidate in high-performance electronics and optoelectronics.展开更多
Organic-inorganic metal-halide perovskite solar cells(PerSCs)have achieved significant progresses due to their outstanding optoelectronic charac-teristics,and the power conversion efficiency(PCE)of single-junction Per...Organic-inorganic metal-halide perovskite solar cells(PerSCs)have achieved significant progresses due to their outstanding optoelectronic charac-teristics,and the power conversion efficiency(PCE)of single-junction PerSCs has been boosted from 3.8%to a certified 25.2%.However,the efficien-cy of single-junction cells is governed by the Shockley-Queisser(S-Q)radiative limit,and fabricating all-perovskite tandem solar cells is a particularly attractive method to break the S-Q limit.Since the bandgap of lead(Pb)-based mixed halide perovskite can be tuned from 1.55 eV to 2.3 eV,and the mixed tin(Sn)-Pb perovskites have bandgap of~1.2 eV,these perovskites become the best candidates for the front and rear subcells of all-perovskite tandem device,respectively.In this review,we firstly summarize the current development progresses of two-terminal(2-T)all-perovskite tandem so-lar cells.For further optimizing the device performance,the wide bandgap mixed halide perovskites for front subcell,mixed Sn-Pb narrow bandgap perovskites for rear subcell,and the interconnection layer(ICL)of 2-T tandem device are then discussed.This review aims to open a pathway to real-ize highly efficient all-perovskite tandem solar cells.展开更多
Three zwitterionic and one cationic N-heterocyclic allenylidene(NHA)platinum(Ⅱ)complexes were prepared and characterized via NMR,HR-MS;and FT-IR,etc.Single crystal structure analyses revealed the various intermolecul...Three zwitterionic and one cationic N-heterocyclic allenylidene(NHA)platinum(Ⅱ)complexes were prepared and characterized via NMR,HR-MS;and FT-IR,etc.Single crystal structure analyses revealed the various intermolecular packing modes vio multiple noncovalent interactions(short Pt…Pt contacts,π-π interactions).The spectroscopic data demonstrated stability of the allenylidene metal complexes is largely ascribed to the resonance structures of zwitterionic acetylide.The zwitterionic and analogue cationic NHA Pt(Ⅱ)monomers showed similar steady-state photoluminescent properties in dilute fluid solution.Highly efficient solid-state phosphorescent emissions(quantum yield up to 20%)of these NHA Pt(Ⅱ)complexes are correlated with their dispersive metallophilic Pt…Pt interactions.HR-MS spectrum indicated zwitterionic monomers can self-assemble into oligomers,such as dimer,trimer and even hexamer in a mixed H_(2)0/Me0H solvent.Meanwhile,molecular aggregates showed variable red-shifted phosphorescence by manipulating the concentration,temperature,time and solvent in the self-assembly of zwitterionic NHA platinum(Ⅱ)complex.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.52072272,52171145 and 22109120)the Zhejiang Provincial Natural Science Foundation of China (LQ21B030002)+1 种基金the Zhejiang Provincial Special Support Program for High-level Talents (2019R52042)the Key programs for Science and Technology Innovation of Wenzhou (ZG2022037)。
文摘The scarcity,high cost and susceptibility to CO of Platinum severely restrict its application in alkaline hydrogen oxidation reaction(HOR).Hybridizing Pt with other transition metals provides an effective strategy to modulate its catalytic HOR performance,but at the cost of mass activity due to the coverage of modifiers on Pt surface.Herein,we constructed dual junctions'Pt/nitrogen-doped carbon(Pt/NC)andδ-MoC/NC to modify electronic structure of Pt via interfacial electron transfer to acquire Pt-MoC@NC catalyst with electron-deficient Pt nanoparticles,simultaneously endowing it with high mass activity and durability of alkaline HOR.Moreover,the unique structure of Pt-MoC@NC endows Pt with a high COtolerance at 1,000 ppm CO/H_(2),a quality that commercial Pt-C catalyst lacks.The theoretical calculations not only confirm the diffusion of electrons from Pt/NC to Mo C/NC could occur,but also demonstrate the negative shift of Pt d-band center for the optimized binding energies of*H,*OH and CO.
基金supported by National Key Research and Development Program of China(2019YFC1605003-3)Fujian Science Foundation for Distinguished Young Scholars(2020J06024).
文摘Emerging evidence shows that dietary oligosaccharides are important prebiotics that can improve intestinal flora,while dietary polyphenols can act directly on intestinal cells.However,information about their synergistic effects on gut health is still limited.In this study,alginate oligosaccharide(AOS)and cyanidin-3-O-glucoside(C3G)were selected as a common marine plant oligosaccharide and terrestrial plant polyphenol,respectively,to study their effects on intestinal health.The results show that,in comparison to their individual applications,the combination of AOS and C3G(mass ratio,3:1)displayed a stronger ability to up-regulate the expression of tight junction proteins,while enhanced intestinal epithelial barrier was also observed and levels of mucin-2 andβ-defensins were simultaneously increased in the intestinal mucus.Interestingly,the secretion of immunoglobulin A and immune-related cytokines were approximately doubled by the AOS+C3G mixture.In addition,the AOS+C3G mixture was found to be more conducive to the positive transformation of intestinal flora,which stimulated the growth of beneficial bacteria Akkermansia,Lachnospiraceae and Feacalibaculum while inhibiting the growth of harmful bacteria Helicobacter and Turicibacter.The data generated herein thus suggests that dietary oligosaccharides and dietary polyphenols may be more beneficial to intestinal health when applied in combination than their individual effects alone.
基金partly supported by the National Key Research and Development Plan Intelligent Robot Key Project(2018YFB1308000)the Key Research and Development Program of Zhejiang Province(2020C01109)。
文摘The stabilization problem of distributed proportional-integral-derivative(PID)controllers for general first-order multi-agent systems with time delay is investigated in the paper.The closed-loop multi-input multi-output(MIMO)framework in frequency domain is firstly introduced for the multi-agent system.Based on the matrix theory,the whole system is decoupled into several subsystems with respect to the eigenvalues of the Laplacian matrix.Considering that the eigenvalues may be complex numbers,the consensus problem of the multi-agent system is transformed into the stabilizing problem of all the subsystems with complex coefficients.For each subsystem with complex coefficients,the range of admissible proportional gains is analytically determined.Then,the stabilizing region in the space of integral gain and derivative gain for a given proportional gain value is also obtained in an analytical form.The entire stabilizing set can be determined by sweeping proportional gain in the allowable range.The proposed method is conducted for general first-order multi-agent systems under arbitrary topology including undirected and directed graph topology.Besides,the results in the paper provide the basis for the design of distributed PID controllers satisfying different performance criteria.The simulation examples are presented to check the validity of the proposed control strategy.
基金This study was supported by the National Key Research and Development Program of China(2019YFE0112200)the Science and Technology Development Fund of Macao SAR,China(0073/2019/AMJ)+2 种基金the National Natural Science Foundation of China(51873007,21835006,51961165102,and 52003022)the Fundamental Research Funds for the Central Universities of China(PT2021-02,buctrc202009)the high-performance computing platform of BUCT.
文摘Fluorescent carbon dots(CDs)have recently become a research hotspot in multidisciplinary fields owing to their distinctive advantages,including outstanding photoluminescence properties,high biocompatibility,low toxicity,and abundant raw materials.Among the promising CDs,narrow‐bandwidth emissive CDs with high color purity have emerged as a rising star in recent years because of their significant potential applications in bioimaging,information sensing,and photoelectric displays.In this review,the state-of-the-art advances of narrow-bandwidth emissive CDs are systematically summarized,and the factors influencing the emission bandwidth,preparation methods,and applications of narrow-bandwidth emissive CDs are described in detail.Besides,existing challenges and future perspectives for achieving high-performance narrow-bandwidth emissive CDs are also discussed.This overview paper is expected to generate more interest and promote the rapid development of this significant research area.
文摘125 μm-breath sensor with high sensitivity and rapid response was prepared by using n-type Si: Au material. Its sensitivity coefficient and time constant were 4 V.sec / L and 38 msec, respec-tively. Its working principle was based on ano- malous resistance effect, which not only increa- sed the sensitivity, but also reduced its time con-stant greatly. Its signal processing system can select the breath signals and work stably. Therefore, the small changes of breath system can be measured and, especially, patient’s breath rate can be monitored at a distance.
基金This work was supported by the National Natural Science Foundation of China （Nos. 61471270, 51420105002, and 51572199）.
文摘In-plane symmetry is an important contributor to the physical properties of two-dimensional layered materials, as well as atomically thin heterojunctions. Here, we demonstrate anisotropic/isotropic van der Waals （vdW） heterostructures of ReS2 and MoS2 monolayers, where interlayer coupling interactions and charge separation were observed by in situ Raman-photoluminescence spectroscopy, electrical, and photoelectrical measurements. We believe that these results could be helpful for understanding the fundamental physics of atomically thin vdW heterostructures and creating novel electronic and optoelectronic devices.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Nos. 21471117, 21173159, 21563009, and 51420105002）.
文摘AgNO3 is often used in the preparation of Au nanostructures since Ag-based substances （AgBS） can selectively be adsorbed on Au（100） and significantly modulate the growth of Au nanocrystals. High-index-faceted Au nanostructures have demonstrated excellent performance in catalysis and surface enhanced Raman scattering （SERS）, thus attracting the interest of many researchers in the past several decades. Herein, high-index-faceted Pd@Au concave nanocubes （CNCs） were prepared using AgBS as growth-directing agents in the heterogeneous growth of Au on Pd nanocubes （NCs）. During the growth of Pd@Au CNCs, Au atoms are initially deposited on the Pd{100} facets leading to the formation of thin Au shells, and then AgBS are quickly adsorbed on the formed Au（100）, favoring the growth along 〈111〉 and the formation of Pd@Au CNCs. Transmission electron microscopy （TEM）, high resolution transmission electron microscopy （HRTEM）, energy dispersive spectroscopy （EDS）, high angle annular dark field （HAADF）, and scanning transmission electron microscopy EDS （STEM- EDS） were used to systematically investigate the growth of Pd@Au CNCs. We also demonstrated that the high-index-faceted Pd@Au CNCs exhibited excellent SERS performances.
基金The authors are grateful for financial support from the National Natural Science Foundation of China(Nos.51920105004,51420105002,and 51572199)the Zhejiang Provincial Natural Science Foundation of China(No.LY19E030008).J.L.would like to thank Yaqi Huang for drawing the schematic.
文摘Two-dimensional(2D)WS2 offers great prospects for assembling next-generation optoelectronic and electronic devices due to its thickness-dependent optical and electronic properties.However,layer-number-controlled growth of WS2 is still a challenge up to now.This work presents controlled growth of bilayer WS2 triangular flakes by carbon-nanoparticle-assisted chemical vapor deposition(CVD)process.The growth mechanism is also proposed.In addition,the field effect transistors(FETs)based on monolayer and bilayer WS2 are also fabricated and investigated.The bilayer FET displays a mobility of 34 cm2·V^-1·s^-1,much higher than that of the monolayer FET.The high figures of merit make bilayer WS2 a promising candidate in high-performance electronics and optoelectronics.
基金supported by the National Natural Science Foundation of China(Nos.51873007,21835006,51961165102,51772218)the Open Project of Key Laboratory of Solar Energy Utilization&Energy Saving Technology of Zhejiang Province(ZJS-OP-2020-04)the State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(Grant No.LAPS20003).
文摘Organic-inorganic metal-halide perovskite solar cells(PerSCs)have achieved significant progresses due to their outstanding optoelectronic charac-teristics,and the power conversion efficiency(PCE)of single-junction PerSCs has been boosted from 3.8%to a certified 25.2%.However,the efficien-cy of single-junction cells is governed by the Shockley-Queisser(S-Q)radiative limit,and fabricating all-perovskite tandem solar cells is a particularly attractive method to break the S-Q limit.Since the bandgap of lead(Pb)-based mixed halide perovskite can be tuned from 1.55 eV to 2.3 eV,and the mixed tin(Sn)-Pb perovskites have bandgap of~1.2 eV,these perovskites become the best candidates for the front and rear subcells of all-perovskite tandem device,respectively.In this review,we firstly summarize the current development progresses of two-terminal(2-T)all-perovskite tandem so-lar cells.For further optimizing the device performance,the wide bandgap mixed halide perovskites for front subcell,mixed Sn-Pb narrow bandgap perovskites for rear subcell,and the interconnection layer(ICL)of 2-T tandem device are then discussed.This review aims to open a pathway to real-ize highly efficient all-perovskite tandem solar cells.
基金the National Natural Science Foundation of China(Nos.21873044 and 21901109)Science and Technology Innovation Commission of Shenzhen Municipality(No.JCYJ 20170817104715174)the Guangdong Major Project of Basic and Applied Basic Research(No.2019B030302009).
文摘Three zwitterionic and one cationic N-heterocyclic allenylidene(NHA)platinum(Ⅱ)complexes were prepared and characterized via NMR,HR-MS;and FT-IR,etc.Single crystal structure analyses revealed the various intermolecular packing modes vio multiple noncovalent interactions(short Pt…Pt contacts,π-π interactions).The spectroscopic data demonstrated stability of the allenylidene metal complexes is largely ascribed to the resonance structures of zwitterionic acetylide.The zwitterionic and analogue cationic NHA Pt(Ⅱ)monomers showed similar steady-state photoluminescent properties in dilute fluid solution.Highly efficient solid-state phosphorescent emissions(quantum yield up to 20%)of these NHA Pt(Ⅱ)complexes are correlated with their dispersive metallophilic Pt…Pt interactions.HR-MS spectrum indicated zwitterionic monomers can self-assemble into oligomers,such as dimer,trimer and even hexamer in a mixed H_(2)0/Me0H solvent.Meanwhile,molecular aggregates showed variable red-shifted phosphorescence by manipulating the concentration,temperature,time and solvent in the self-assembly of zwitterionic NHA platinum(Ⅱ)complex.
