Glioblastoma(GBM) remains a formidable challenge in oncology.Chemodynamic therapy(CDT) that triggers tumor cell death by reactive oxygen species(ROS) could open up a new door for GBM treatment.Herein,we report a novel...Glioblastoma(GBM) remains a formidable challenge in oncology.Chemodynamic therapy(CDT) that triggers tumor cell death by reactive oxygen species(ROS) could open up a new door for GBM treatment.Herein,we report a novel CDT nanoagent.Hemoglobin(Hb)and glucose oxidase(GOx) were employed as powerful CDT catalysts.Instead of encapsulating the proteins in drug delivery nanocarriers,we formulate multimeric superstructures as self-delivery entities by crosslinking techniques.Red blood cell(RBC) membranes are camouflaged on the protein superstructures to promote the delivery across blood-brain barrier.The as-prepared RBC@Hb@GOx nanoparticles(NPs) offer superior biocompatibility,simplified structure,and high accumulation at the tumor site.We successfully demonstrated that the NPs could efficiently produce toxic ROS to kill U87 MG cancer cells in vitro and inhibit the growth of GBM tumor in vivo,suggesting that the new CDT nanoagent holds great promise for treating GBM.展开更多
Urchin-like Ni O superstructures have been prepared via a thermal decomposition reaction of Ni C_2O_4 at 400 for 1h. The morphology and structure of the synthesized urchin-like superstructures have been characterized ...Urchin-like Ni O superstructures have been prepared via a thermal decomposition reaction of Ni C_2O_4 at 400 for 1h. The morphology and structure of the synthesized urchin-like superstructures have been characterized by X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. The results show that urchin-like Ni O superstructures were a polycrystal with cubic structure and typical diameters of 200 to 500 nm and the self-assembly nanoparticles average diameter is 14 nm. The as-prepared Ni O superstructures have a high Brunauer-Emmett-Teller surface area of about 60.32 m^2/g. The UV-vis spectrum of urchin-like Ni O consists of one peak at 357 nm(3.47 e V).展开更多
Mitochondria, usually ovoid structures no larger than 0.5 microns can fuse into structures that are 5 microns and larger such as nebenkern, spheroidal or cup-shaped mitochondria, and even mega-mitochondria. In studyin...Mitochondria, usually ovoid structures no larger than 0.5 microns can fuse into structures that are 5 microns and larger such as nebenkern, spheroidal or cup-shaped mitochondria, and even mega-mitochondria. In studying differentiation of human endometrial epithelial cells, it became clear that formation of mitochondrial superstructures was an essential part of the process. In this paper, the origins, function, and demise of these superstructures called mitonucleons are described. In the course of reading papers about mitochondrial superstructures, it became obvious that there are important similarities, particularly with regard to function, between the mitonucleon and the nebenkern, a superstructure essential for dramatic tail elongation during spermatogenesis in grasshoppers, drosophila, and other insects. Close inspection of photomicrographs of differentiating mitonucleons during the first 12 hours suggests that gases build up in vacuoles within the mitochondrial superstructure creating pressure that elevates syncytial membranes and compresses nuclear aggregates contained within the mitonucleon.展开更多
The ultrathinβ-Sn(001)films have attracted tremendous attention owing to its topological superconductivity(TSC),which hosts Majorana bound state(MBSs)for quantum computation.Recently,β-Sn(001)thin films have been su...The ultrathinβ-Sn(001)films have attracted tremendous attention owing to its topological superconductivity(TSC),which hosts Majorana bound state(MBSs)for quantum computation.Recently,β-Sn(001)thin films have been successfully fabricated via phase transition engineering.However,the understanding of structural phase transition ofβ-Sn(001)thin films is still elusive.Here,we report the direct growth of ultrathinβ-Sn(001)films epitaxially on the highly oriented pyrolytic graphite(HOPG)substrate and the characterization of intricate structural-transition-induced superstructures.The morphology was obtained by using atomic force microscopy(AFM)and low-temperature scanning tunneling microscopy(STM),indicating a structure-related bilayer-by-bilayer growth mode.The ultrathinβ-Sn film was made of multiple domains with various superstructures.Both high-symmetric and distorted superstructures were observed in the atomic-resolution STM images of these domains.The formation mechanism of these superstructures was further discussed based on the structural phase transition ofβtoα-Sn at the atomic-scale thickness.Our work not only brings a deep understanding of the structural phase transition of Sn film at the two-dimensional limit,but also paves a way to investigate their structure-sensitive topological properties.展开更多
Using scanning tunneling microscopy we observe a stripe phase smoothly interfacing with a triangular 2 ×2 super- structure on the surface of 2H-NbSe2 single crystM. Proximity-induced superconductivity is demonstr...Using scanning tunneling microscopy we observe a stripe phase smoothly interfacing with a triangular 2 ×2 super- structure on the surface of 2H-NbSe2 single crystM. Proximity-induced superconductivity is demonstrated in these new ordered structures by measurements of low-temperature tunneling spectra. The modulation of superconduc- tivity by the reconstruction provides an opportunity to understand the interplay between superconductivity and charge orders.展开更多
The fabrication of well defined hierarchical structures of anatase TiO_(2) with a high percentage of reactive facets is of great importance and challenging.Hierarchically flower-like TiO_(2) superstructures(HFTS)self-...The fabrication of well defined hierarchical structures of anatase TiO_(2) with a high percentage of reactive facets is of great importance and challenging.Hierarchically flower-like TiO_(2) superstructures(HFTS)self-assembled from anatase TiO_(2) nanosheets with exposed{001}facets(up to 87%)were synthesized by a simple alcohothermal strategy in a HF-H_(2)O-C_(2)H_(5)OH mixed solution using titanate nanotubes as precursor.The samples were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,and N2 adsorption-desorption isotherms.The photocatalytic activity was evaluated by the photocatalytic oxidation decomposition of acetone in air and methyl orange in aqueous solution under UV illumination.The photocatalytic activity of HFTS was much higher than that of commercial Degussa P25 and tabular-shaped anatase TiO_(2) obtained using pure water as the synthesis medium.The enhancement in photocatalytic activity was related to several factors,including the hierarchically porous structure,exposed{001}facets,and increased light harvesting ability.The HFTS was also of interest for use in solar cells,photocatalytic H_(2) production,optoelectronic devices,sensors,and catalysis.展开更多
Since there may exist dark matter particles ν and δ with mass - 10^-1 e V in the universe, the superstructures with a scale of 10^19 solar masses (large number A - 10^19) appeared during the era near and before th...Since there may exist dark matter particles ν and δ with mass - 10^-1 e V in the universe, the superstructures with a scale of 10^19 solar masses (large number A - 10^19) appeared during the era near and before the hydrogen recombination. Since there are superstructures in the universe, there may be no necessity for the existence of dark energy. For checking the superstructure in the universe by CMB anisotropy, we need to measure CMB angular power spectrum especially around ten degrees across the sky- in more details, While neutrino u is related to electroweak unification, the fourth stable elementary particle 6 may be related to strong-gravity unification, which suggests p + p^- → n + δ^- and that some new baryons appeared in the TeV region.展开更多
Hydrogen evolution electrocatalysts derived from metal-organic crystalline frameworks can inherit the merits of ordered and adjustable structures with high surface area.In this paper,organic-octamolybdate crystalline ...Hydrogen evolution electrocatalysts derived from metal-organic crystalline frameworks can inherit the merits of ordered and adjustable structures with high surface area.In this paper,organic-octamolybdate crystalline superstructures(OOCS)with a fixed stoichiometric ratio of Mo_(8)(L)_(2) and high Mo content(>40 wt%)were synthesized using flexible ligands with controllable lengths(named as OOCS-1-3).Then,molybdenum carbides coated with carbon layers as electrocatalysts(Mo_(2)C@C-1-3)can be obtained directly from a one-step high-temperature carbonization process using OOCS-1-3 as precursors.As a typical example,Mo_(2)C@C-3 exhibits satisfactory hydrogen evolution activity with a low overpotential of 151 m V(1.0 mol/L KOH)at 10 m A/cm^(2) and stability for 24 h.The electrocatalytic activity is mainly from the synergistic interactions between the carbon layers and molybdenum carbide species.Furthermore,compared with the initial content of C,N,Mo in OOCS and Mo_(2)C@C,the catalytic activity increases with the N amount.This work makes organic-octamolybdate crystalline superstructures used as general precursors to product high Mo content electrocatalysts applied in energy storage and conversion fields.展开更多
Low-dimensional materials have attracted increasing attention due to their guiding significance for material preparation and potential wide-ranging applications.Through the controllable synthesis and suitably designed...Low-dimensional materials have attracted increasing attention due to their guiding significance for material preparation and potential wide-ranging applications.Through the controllable synthesis and suitably designed fusion of lowdimensional materials into ordered complex superstructures,it has become an effective way to explore new properties of materials and construct structures meeting new application needs.Based on low-dimensional materials such as metal oxides,copolymers,metal-organic complexes,and organic crystals,great efforts have been devoted to the design and construction of complex superstructures with regular repeatability.A series of unique cases including multi-block,core/multi-shell,hyperbranched and network structures have been reported,which has promoted the development of the field of material preparation.Herein,we summarize representative progress of low-dimensional complex superstructures in a reasonable structure classification manner.Ultimately,the existing challenges are discussed,and an outlook is given for future study of precise construction of superstructures as well as exploitation of potential applications.展开更多
Two-dimensional(2D)magnetic materials promise unconventional properties and quantum phases as well as advances in ultracompact spintronics.Miniaturization of 2D magnets often reaches a single monolayer but in general ...Two-dimensional(2D)magnetic materials promise unconventional properties and quantum phases as well as advances in ultracompact spintronics.Miniaturization of 2D magnets often reaches a single monolayer but in general can go beyond this limit,as demonstrated by 2D magnetism of submonolayer Eu superstructures coupled with Si.The question is whether the submonolayer magnetism constitutes a general phenomenon.Herein,we demonstrate that regular Eu lattices form a class of 2D magnets displaying various structures,stoichiometries,and chemical bonding.We synthesized and studied a set of Eu superstructures on Ge(001).Their magnetic properties are consistent with the emergence of a magnetic order such as ferro-or ferrimagnetism.In particular,control over the magnetic transition temperature by weak magnetic fields indicates the 2D nature of the magnetism.Taken together,Eu/Ge and Eu/Si superstructures seed a nucleus of the research area addressing the emergence of magnetism in submonolayer chemical species.展开更多
Controllable design of the catalytic electrodes with hierarchical superstructures is expected to improve their electrochemical performance.Herein,a self-supported integrated electrode(NiCo-ZLDH/NF)with a unique hierar...Controllable design of the catalytic electrodes with hierarchical superstructures is expected to improve their electrochemical performance.Herein,a self-supported integrated electrode(NiCo-ZLDH/NF)with a unique hierarchical quaternary superstructure was fabricated through a self-sacrificing template strategy from the metal–organic framework(Co-ZIF-67)nanoplate arrays,which features an intriguing well-defined hierarchy when taking the unit cells of the NiCo-based layered double hydroxide(NiCo-LDH)as the primary structure,the ultrathin LDH nanoneedles as the secondary structure,the mesoscale hollow plates of the LDH nanoneedle arrays as the tertiary structure,and the macroscale three-dimensional frames of the plate arrays as the quaternary structure.Notably,the distinctive structure of NiCo-ZLDH/NF can not only accelerate both mass and charge transfer,but also expose plentiful accessible active sites with high intrinsic activity,endowing it with an excellent electrochemical performance for urea oxidation reaction(UOR).Specially,it only required the low potentials of 1.335,1.368 and 1.388 V to deliver the current densities of 10,100 and 200 mA cm^(-2),respectively,much superior to those for typical NiCo-LDH.Employing NiCo-ZLDH/NF as the bifunctional electrode for both anodic UOR and cathodic HER,an energy-saving electrolysis system was further explored which can greatly reduce the needed voltage of 213 mV to deliver the current density of 100 mA cm^(-2),as compared to the conventional water electrolysis system composed of OER.This work manifests that it is prospective to explore the hierarchically nanostructured electrodes and the innovative electrolytic technologies for high-efficiency electrocatalysis.展开更多
In the realm of the synthesis of heat-integrated distillation configurations,the conventional approach for exploring more heat integration possibilities typically entails the splitting of a single column into a twocol...In the realm of the synthesis of heat-integrated distillation configurations,the conventional approach for exploring more heat integration possibilities typically entails the splitting of a single column into a twocolumn configuration.However,this approach frequently necessitates tedious enumeration procedures,resulting in a considerable computational burden.To surmount this formidable challenge,the present study introduces an innovative remedy:The proposition of a superstructure that encompasses both single-column and multiple two-column configurations.Additionally,a simultaneous optimization algorithm is applied to optimize both the process parameters and heat integration structures of the twocolumn configurations.The effectiveness of this approach is demonstrated through a case study focusing on industrial organosilicon separation.The results underscore that the superstructure methodology not only substantially mitigates computational time compared to exhaustive enumeration but also furnishes solutions that exhibit comparable performance.展开更多
The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of an...The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of anthraquinone-based COFs(i.e.,AAn-COF and OH-AAn-COF)with tunable 1D superstructures(e.g.,nanofibers(NF)and hollow tubes(HT))have been produced via Schiff-base condensation reaction.Interestingly,a rarely reported nanosheet-based self-template mechanism and a nanosheet-crimping mechanism have been demonstrated for the production of COF-based nanofibers and hollow tubes,respectively.Besides,the obtained COF-based superstructures can be post-modified with transition metals for efficient CO_(2)RR.Specifically,AAn-COF-Cu(NF)and OH-AAn-COF-Cu(HT)exhibit superior faradaic-efficiency with CH_(4)(FECH_(4))of 77%(-128.1 mA cm^(-2),-0.9 V)and 61%(-99.5 mA cm^(-2),-1.0 V)in a flow-cell,respectively.Noteworthy,the achieved FECH_(4) of AAn-COF-Cu(NF)(77%)is the highest one among reported crystalline COFs.This work provides a general methodology in exploring morphology-controlled COFs for electrocatalytic CO_(2)RR.展开更多
Mesocrystals, the non-classical crystals with highly ordered nanoparticle superstructures, have shown great potential in many applications because of their newly collective properties. However, there is still a lack o...Mesocrystals, the non-classical crystals with highly ordered nanoparticle superstructures, have shown great potential in many applications because of their newly collective properties. However, there is still a lack of a facile and general synthesis strategy to organize and integrate distinct components into complex mesocrystals, and of reported application for them in industrial catalytic reactions. Herein we report a general bottom-up synthesis of CuO-based trimetallic oxide mesocrystals (denoted as CuO-M1Ox-M2Oy, where M1 and M2 = Zn, In, Fe, Ni, Mn, and Co) using a simple precipitation method followed by a hydrothermal treatment and a topotactic transformation via calcination. When these mesocrystals were used as the catalyst to produce trichlorosilane (TCS) via Si hydrochlorination reaction, they exhibited excellent catalytic performance with much increased Si conversion and TCS selectivity. In particular, the TCS yield was increased 19-fold than that of the catalyst-free process. The latter is the current industrial process. The efficiently catalytic property of these mesocrystals is attributed to the formation of well-defined nanoscale heterointerfaces that can effectively facilitate the charge transfer, and the generation of the compressive and tensile strain on CuO near the interfaces among different metal oxides. The synthetic approach developed here could be applicable to fabricate versatile complicated metal oxide mesocrystals as novel catalysts for various industrial chemical reactions.展开更多
Fullerene assembling with specific donor molecules would yield multi-functional metamaterials via the collective behavior,wherein linear acenes are widely used as donor molecules to construct the charge‐transfer hete...Fullerene assembling with specific donor molecules would yield multi-functional metamaterials via the collective behavior,wherein linear acenes are widely used as donor molecules to construct the charge‐transfer heterojunction structure with fullerene.However,they are generally prepared by vacuum deposition due to the insoluble property of high‐performance linear acenes molecules in common solvents,which makes the construction of fullerene with insoluble donor molecules still be a big challenge in the solution‐processed method.To this end,chemical modification provides an effective solution‐processed strategy to construct donor and acceptor systems.Here,the C60‐pentacene is assembled into controllable flower‐like superstructures by the surface grafting method.It is found that the nanofeatures of the microflowers could be regulated by temperature,resulting in dense‐flakes morphology at room temperature and loose flakes at high temperatures.Furthermore,the dense‐flakes microflowers structures with less mass but better crystalline structure exhibit better optoelectronic properties.Our results reveal an effective control on the nanofeatures of the self‐assembled fullerenes complex super-structures and their role for the optoelectronic performance,which may promote the exploring of fullerene superstructures as photodetectors.展开更多
This paper investigates the impact of differential foundation settlement on the reliability of bridge superstructure based on loads and resistances statistical properties in Missouri State.Maximum deterministic differ...This paper investigates the impact of differential foundation settlement on the reliability of bridge superstructure based on loads and resistances statistical properties in Missouri State.Maximum deterministic differential settlement is often used in current AASHTO LRFD(load and resistance factored design)specification.However,the expected foundation settlement is quite different from the actual settlement due to the soil’s large variability.Therefore,it makes sense to consider settlement as a random variable.In this paper,a lognormal distribution with coefficient of variation of 0.25 of random settlement is considered in reliability analysis based on limited previous studies.Dead and live loads are modeled as random variables with normal and Gumbel Type I distributions,respectively.Considering the regional traffic condition on Missouri roadways,the live load effect on existing bridges based on weight-in-motion data is also investigated.The calibrated resistance statistical properties such as bias and COV(coefficient of variance)are used for reliability analysis.Total 14 existing bridges based on Strength I Limit State are analyzed.Since no differential settlement is considered in the past designed bridges in Missouri,small differential settlement can significantly reduce the reliability indices of the superstructure,depending upon the span length and rigidity of the girder.The analysis results also show that the reliability of existing steel-girder bridges is consistently higher than prestressed concrete and solid slab bridges;the shorter and stiffer the spans,the more significant the settlement’s effect on the reliability of bridge superstructures;As the span length ratio becomes less than 0.75,the girder and solid slab bridges’reliability drops significantly at small settlements.展开更多
As a distinct type of nanocapsules,hollow superstructures of inorganic nanoparticles have attracted increasing attention due to their controllable permeability,convenient functionalization,and efficient surface utiliz...As a distinct type of nanocapsules,hollow superstructures of inorganic nanoparticles have attracted increasing attention due to their controllable permeability,convenient functionalization,and efficient surface utilization.Conventionally,they are produced by assembling nanoparticles against expensive sacrificial templates.Herein,a general emulsion-based method is reported to assemble colloidal nanoparticles into submicron hollow superstructures,involving first co-assembly of colloidal nanoparticles with organic additives to form clusters,then overcoating the clusters with a polymer shell,and finally removing the organic additives and re-dispersing nanoparticles by exposing to a good solvent.The key to the success of this process is the re-assembly of nanoparticles against the polymer shells as driven by the capillary force during solvent evaporation,producing hollow superstructures.Such a space-confined assembly process can be well controlled by choice of solvents and their evaporation rates.This general technique provides an open and low-cost platform for creating hollow superstructures of various inorganic nanoparticles,offering many opportunities for exploring unique applications that can take advantage of the collective properties of the constituent nanoparticles and the permeable nanoshell structures.展开更多
Utilizing vacuum-tuned-atmosphere induced dip coating method,we achieve the cross-dimensional macroscopic diverse self-assemblies by using one building block with one chemical functionality.Coordinated modulating the ...Utilizing vacuum-tuned-atmosphere induced dip coating method,we achieve the cross-dimensional macroscopic diverse self-assemblies by using one building block with one chemical functionality.Coordinated modulating the vacuum degree,colloid concentration and evaporation atmosphere,Au@Ag core/shell nanocubes (NCs) can controllably assemble into diverse multi-dimensional superstructures.Under 0.08 MPa,we obtained the two-dimensional (2D) stepped superstructures with continuously tunable step width.In addition,we generated a series of tailorable nanoscale-roughened 2D Au@Ag NCs superstructures at 0.04 MPa,which exhibited the label-free ultrasensitive SERS detection for the different mutants of IAPP8-37 proteins.Under 0.01 MPa,we obtained the cross-dimensional tailorable Au@Ag NCs assemblies from random to macroscale 2D and three-dimensional (3D) densest superstructures by adjusting the capping ligand-environmental molecule interactions.This is a flexible method to generate as-prepared Au@Ag core/shell NCs into well-defined macroscopic diverse superstructures and to promote the exploitation into biological applications.展开更多
Hierarchical superstructures assembled by nanosheets can effectively prevent aggregation of nanosheets and improve performance in energy storage.Therefore,we proposed a facile hydrothermal method to obtain three-dimen...Hierarchical superstructures assembled by nanosheets can effectively prevent aggregation of nanosheets and improve performance in energy storage.Therefore,we proposed a facile hydrothermal method to obtain three-dimensional(3D)superstructure assembled by nanosheets.We found that the ratio of Co^(2+)/HMTA affected the morphology of the samples,and the 3D hierarchical structures of are obtained while the ratio of Co^(2+)/HMTA is 12:25.The hierarchical structures with sufficient interior space preserves the original sheet-like dimensional components and results in sufficient active sites and efficient mass diffusion.Hence,the 3D Co_(2)V_(2)O_(7)·nH_(2)O hierarchical structure exhibits good rate capability and high stability while as electrode materials.Meanwhile,when power density is 745.13 W/kg,the assembled CVO-2//AC shows an energy density of 47.7 Wh/kg.The work displays a facile method for fabrication of 3D superstructure assembled by 2D nanosheets that can be applied in energy storage.展开更多
基金supported by the Villum Fonden, Denmark, Project No. 13153the China Scholarship Council (CSC) for its generous support。
文摘Glioblastoma(GBM) remains a formidable challenge in oncology.Chemodynamic therapy(CDT) that triggers tumor cell death by reactive oxygen species(ROS) could open up a new door for GBM treatment.Herein,we report a novel CDT nanoagent.Hemoglobin(Hb)and glucose oxidase(GOx) were employed as powerful CDT catalysts.Instead of encapsulating the proteins in drug delivery nanocarriers,we formulate multimeric superstructures as self-delivery entities by crosslinking techniques.Red blood cell(RBC) membranes are camouflaged on the protein superstructures to promote the delivery across blood-brain barrier.The as-prepared RBC@Hb@GOx nanoparticles(NPs) offer superior biocompatibility,simplified structure,and high accumulation at the tumor site.We successfully demonstrated that the NPs could efficiently produce toxic ROS to kill U87 MG cancer cells in vitro and inhibit the growth of GBM tumor in vivo,suggesting that the new CDT nanoagent holds great promise for treating GBM.
基金supported by Fund of Weinan Teachers University(10YKF014)
文摘Urchin-like Ni O superstructures have been prepared via a thermal decomposition reaction of Ni C_2O_4 at 400 for 1h. The morphology and structure of the synthesized urchin-like superstructures have been characterized by X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. The results show that urchin-like Ni O superstructures were a polycrystal with cubic structure and typical diameters of 200 to 500 nm and the self-assembly nanoparticles average diameter is 14 nm. The as-prepared Ni O superstructures have a high Brunauer-Emmett-Teller surface area of about 60.32 m^2/g. The UV-vis spectrum of urchin-like Ni O consists of one peak at 357 nm(3.47 e V).
文摘Mitochondria, usually ovoid structures no larger than 0.5 microns can fuse into structures that are 5 microns and larger such as nebenkern, spheroidal or cup-shaped mitochondria, and even mega-mitochondria. In studying differentiation of human endometrial epithelial cells, it became clear that formation of mitochondrial superstructures was an essential part of the process. In this paper, the origins, function, and demise of these superstructures called mitonucleons are described. In the course of reading papers about mitochondrial superstructures, it became obvious that there are important similarities, particularly with regard to function, between the mitonucleon and the nebenkern, a superstructure essential for dramatic tail elongation during spermatogenesis in grasshoppers, drosophila, and other insects. Close inspection of photomicrographs of differentiating mitonucleons during the first 12 hours suggests that gases build up in vacuoles within the mitochondrial superstructure creating pressure that elevates syncytial membranes and compresses nuclear aggregates contained within the mitonucleon.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61674045,61911540074,and 21622304)the Fund from the Ministry of Science and Technology of China(Grant No.2016YFA0200700)+1 种基金the Strategic Priority Research Program and Key Research Program of Frontier Sciences(Chinese Academy of Sciences)(Grant Nos.XDB30000000 and QYZDB-SSW-SYS031)Zhihai Cheng was supported by the Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China(Grant No.21XNLG27).
文摘The ultrathinβ-Sn(001)films have attracted tremendous attention owing to its topological superconductivity(TSC),which hosts Majorana bound state(MBSs)for quantum computation.Recently,β-Sn(001)thin films have been successfully fabricated via phase transition engineering.However,the understanding of structural phase transition ofβ-Sn(001)thin films is still elusive.Here,we report the direct growth of ultrathinβ-Sn(001)films epitaxially on the highly oriented pyrolytic graphite(HOPG)substrate and the characterization of intricate structural-transition-induced superstructures.The morphology was obtained by using atomic force microscopy(AFM)and low-temperature scanning tunneling microscopy(STM),indicating a structure-related bilayer-by-bilayer growth mode.The ultrathinβ-Sn film was made of multiple domains with various superstructures.Both high-symmetric and distorted superstructures were observed in the atomic-resolution STM images of these domains.The formation mechanism of these superstructures was further discussed based on the structural phase transition ofβtoα-Sn at the atomic-scale thickness.Our work not only brings a deep understanding of the structural phase transition of Sn film at the two-dimensional limit,but also paves a way to investigate their structure-sensitive topological properties.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11574372 and 11322432the 'Strategic Priority Research Program(B)' of the Chinese Academy of Sciences under Grant No XDB07020300
文摘Using scanning tunneling microscopy we observe a stripe phase smoothly interfacing with a triangular 2 ×2 super- structure on the surface of 2H-NbSe2 single crystM. Proximity-induced superconductivity is demonstrated in these new ordered structures by measurements of low-temperature tunneling spectra. The modulation of superconduc- tivity by the reconstruction provides an opportunity to understand the interplay between superconductivity and charge orders.
基金supported by the National Natural Science Foundation of China(50625208,20773097,and 20877061)the National Basic Research Program of China(973Program,2007CB613302and2009CB939704)Fundamental Research Funds for the Central Universities(2010-YB-01)
文摘The fabrication of well defined hierarchical structures of anatase TiO_(2) with a high percentage of reactive facets is of great importance and challenging.Hierarchically flower-like TiO_(2) superstructures(HFTS)self-assembled from anatase TiO_(2) nanosheets with exposed{001}facets(up to 87%)were synthesized by a simple alcohothermal strategy in a HF-H_(2)O-C_(2)H_(5)OH mixed solution using titanate nanotubes as precursor.The samples were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,and N2 adsorption-desorption isotherms.The photocatalytic activity was evaluated by the photocatalytic oxidation decomposition of acetone in air and methyl orange in aqueous solution under UV illumination.The photocatalytic activity of HFTS was much higher than that of commercial Degussa P25 and tabular-shaped anatase TiO_(2) obtained using pure water as the synthesis medium.The enhancement in photocatalytic activity was related to several factors,including the hierarchically porous structure,exposed{001}facets,and increased light harvesting ability.The HFTS was also of interest for use in solar cells,photocatalytic H_(2) production,optoelectronic devices,sensors,and catalysis.
文摘Since there may exist dark matter particles ν and δ with mass - 10^-1 e V in the universe, the superstructures with a scale of 10^19 solar masses (large number A - 10^19) appeared during the era near and before the hydrogen recombination. Since there are superstructures in the universe, there may be no necessity for the existence of dark energy. For checking the superstructure in the universe by CMB anisotropy, we need to measure CMB angular power spectrum especially around ten degrees across the sky- in more details, While neutrino u is related to electroweak unification, the fourth stable elementary particle 6 may be related to strong-gravity unification, which suggests p + p^- → n + δ^- and that some new baryons appeared in the TeV region.
基金financially supported by Joint Fund Project of the Natural Science Foundation of Jilin Province(No.YDZJ202301ZYTS290)。
文摘Hydrogen evolution electrocatalysts derived from metal-organic crystalline frameworks can inherit the merits of ordered and adjustable structures with high surface area.In this paper,organic-octamolybdate crystalline superstructures(OOCS)with a fixed stoichiometric ratio of Mo_(8)(L)_(2) and high Mo content(>40 wt%)were synthesized using flexible ligands with controllable lengths(named as OOCS-1-3).Then,molybdenum carbides coated with carbon layers as electrocatalysts(Mo_(2)C@C-1-3)can be obtained directly from a one-step high-temperature carbonization process using OOCS-1-3 as precursors.As a typical example,Mo_(2)C@C-3 exhibits satisfactory hydrogen evolution activity with a low overpotential of 151 m V(1.0 mol/L KOH)at 10 m A/cm^(2) and stability for 24 h.The electrocatalytic activity is mainly from the synergistic interactions between the carbon layers and molybdenum carbide species.Furthermore,compared with the initial content of C,N,Mo in OOCS and Mo_(2)C@C,the catalytic activity increases with the N amount.This work makes organic-octamolybdate crystalline superstructures used as general precursors to product high Mo content electrocatalysts applied in energy storage and conversion fields.
基金supported by the National Natural Science Foundation of China(52173177,21971185 and 51821002)the Collaborative Innovation Center of Suzhou Nano Science and Technology(CIC-Nano)the“111”Project of the State Administration of Foreign Experts Affairs of China
文摘Low-dimensional materials have attracted increasing attention due to their guiding significance for material preparation and potential wide-ranging applications.Through the controllable synthesis and suitably designed fusion of lowdimensional materials into ordered complex superstructures,it has become an effective way to explore new properties of materials and construct structures meeting new application needs.Based on low-dimensional materials such as metal oxides,copolymers,metal-organic complexes,and organic crystals,great efforts have been devoted to the design and construction of complex superstructures with regular repeatability.A series of unique cases including multi-block,core/multi-shell,hyperbranched and network structures have been reported,which has promoted the development of the field of material preparation.Herein,we summarize representative progress of low-dimensional complex superstructures in a reasonable structure classification manner.Ultimately,the existing challenges are discussed,and an outlook is given for future study of precise construction of superstructures as well as exploitation of potential applications.
基金This work is supported by NRC“Kurchatov Institute”,the Ministry of Science and Higher Education of Russia(Agreement No.075-15-2021-1351)the Russian Science Foundation(grants No.22-13-00004(synthesis)+1 种基金20-79-10028(structural characterization)19-19-00009(studies on magnetism)).
文摘Two-dimensional(2D)magnetic materials promise unconventional properties and quantum phases as well as advances in ultracompact spintronics.Miniaturization of 2D magnets often reaches a single monolayer but in general can go beyond this limit,as demonstrated by 2D magnetism of submonolayer Eu superstructures coupled with Si.The question is whether the submonolayer magnetism constitutes a general phenomenon.Herein,we demonstrate that regular Eu lattices form a class of 2D magnets displaying various structures,stoichiometries,and chemical bonding.We synthesized and studied a set of Eu superstructures on Ge(001).Their magnetic properties are consistent with the emergence of a magnetic order such as ferro-or ferrimagnetism.In particular,control over the magnetic transition temperature by weak magnetic fields indicates the 2D nature of the magnetism.Taken together,Eu/Ge and Eu/Si superstructures seed a nucleus of the research area addressing the emergence of magnetism in submonolayer chemical species.
基金support of the National Natural Science Foundation of China(21901246,22105203 and 22175174)the Natural Science Foundation of Fujian Province(2020J01116 and 2021J06033)the China Postdoctoral Science Foundation(2021TQ0332 and 2021M703215).
文摘Controllable design of the catalytic electrodes with hierarchical superstructures is expected to improve their electrochemical performance.Herein,a self-supported integrated electrode(NiCo-ZLDH/NF)with a unique hierarchical quaternary superstructure was fabricated through a self-sacrificing template strategy from the metal–organic framework(Co-ZIF-67)nanoplate arrays,which features an intriguing well-defined hierarchy when taking the unit cells of the NiCo-based layered double hydroxide(NiCo-LDH)as the primary structure,the ultrathin LDH nanoneedles as the secondary structure,the mesoscale hollow plates of the LDH nanoneedle arrays as the tertiary structure,and the macroscale three-dimensional frames of the plate arrays as the quaternary structure.Notably,the distinctive structure of NiCo-ZLDH/NF can not only accelerate both mass and charge transfer,but also expose plentiful accessible active sites with high intrinsic activity,endowing it with an excellent electrochemical performance for urea oxidation reaction(UOR).Specially,it only required the low potentials of 1.335,1.368 and 1.388 V to deliver the current densities of 10,100 and 200 mA cm^(-2),respectively,much superior to those for typical NiCo-LDH.Employing NiCo-ZLDH/NF as the bifunctional electrode for both anodic UOR and cathodic HER,an energy-saving electrolysis system was further explored which can greatly reduce the needed voltage of 213 mV to deliver the current density of 100 mA cm^(-2),as compared to the conventional water electrolysis system composed of OER.This work manifests that it is prospective to explore the hierarchically nanostructured electrodes and the innovative electrolytic technologies for high-efficiency electrocatalysis.
文摘In the realm of the synthesis of heat-integrated distillation configurations,the conventional approach for exploring more heat integration possibilities typically entails the splitting of a single column into a twocolumn configuration.However,this approach frequently necessitates tedious enumeration procedures,resulting in a considerable computational burden.To surmount this formidable challenge,the present study introduces an innovative remedy:The proposition of a superstructure that encompasses both single-column and multiple two-column configurations.Additionally,a simultaneous optimization algorithm is applied to optimize both the process parameters and heat integration structures of the twocolumn configurations.The effectiveness of this approach is demonstrated through a case study focusing on industrial organosilicon separation.The results underscore that the superstructure methodology not only substantially mitigates computational time compared to exhaustive enumeration but also furnishes solutions that exhibit comparable performance.
基金supported by the National Natural Science Foundation of China(21871141,21871142,21901122,22071109 and 92061101)the Natural Science Research of Jiangsu Higher Education Institutions of China(19KJB150011)+3 种基金China Postdoctoral Science Foundation(2018M630572 and 2019M651873)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX201171)Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Foundation of Jiangsu Collaborative Innovation Center of Biomedical Functional Materials.
文摘The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of anthraquinone-based COFs(i.e.,AAn-COF and OH-AAn-COF)with tunable 1D superstructures(e.g.,nanofibers(NF)and hollow tubes(HT))have been produced via Schiff-base condensation reaction.Interestingly,a rarely reported nanosheet-based self-template mechanism and a nanosheet-crimping mechanism have been demonstrated for the production of COF-based nanofibers and hollow tubes,respectively.Besides,the obtained COF-based superstructures can be post-modified with transition metals for efficient CO_(2)RR.Specifically,AAn-COF-Cu(NF)and OH-AAn-COF-Cu(HT)exhibit superior faradaic-efficiency with CH_(4)(FECH_(4))of 77%(-128.1 mA cm^(-2),-0.9 V)and 61%(-99.5 mA cm^(-2),-1.0 V)in a flow-cell,respectively.Noteworthy,the achieved FECH_(4) of AAn-COF-Cu(NF)(77%)is the highest one among reported crystalline COFs.This work provides a general methodology in exploring morphology-controlled COFs for electrocatalytic CO_(2)RR.
基金the National Natural Science Foundation of China(Nos.21878301,21978299,and 21908224)Z.Z.thanks the kind support of Guangdong Technion Israel Institute of Technology(GTTIT)for the collaboration.
文摘Mesocrystals, the non-classical crystals with highly ordered nanoparticle superstructures, have shown great potential in many applications because of their newly collective properties. However, there is still a lack of a facile and general synthesis strategy to organize and integrate distinct components into complex mesocrystals, and of reported application for them in industrial catalytic reactions. Herein we report a general bottom-up synthesis of CuO-based trimetallic oxide mesocrystals (denoted as CuO-M1Ox-M2Oy, where M1 and M2 = Zn, In, Fe, Ni, Mn, and Co) using a simple precipitation method followed by a hydrothermal treatment and a topotactic transformation via calcination. When these mesocrystals were used as the catalyst to produce trichlorosilane (TCS) via Si hydrochlorination reaction, they exhibited excellent catalytic performance with much increased Si conversion and TCS selectivity. In particular, the TCS yield was increased 19-fold than that of the catalyst-free process. The latter is the current industrial process. The efficiently catalytic property of these mesocrystals is attributed to the formation of well-defined nanoscale heterointerfaces that can effectively facilitate the charge transfer, and the generation of the compressive and tensile strain on CuO near the interfaces among different metal oxides. The synthetic approach developed here could be applicable to fabricate versatile complicated metal oxide mesocrystals as novel catalysts for various industrial chemical reactions.
基金Beijing National Laboratory for Molecular Sciences,Grant/Award Number:BNLMS202006National Natural Science Foundation of China,Grant/Award Numbers:21875108,62004138+1 种基金Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20191289Instrument&Equipment Open Funding of Nanjing University of Science and Technology。
文摘Fullerene assembling with specific donor molecules would yield multi-functional metamaterials via the collective behavior,wherein linear acenes are widely used as donor molecules to construct the charge‐transfer heterojunction structure with fullerene.However,they are generally prepared by vacuum deposition due to the insoluble property of high‐performance linear acenes molecules in common solvents,which makes the construction of fullerene with insoluble donor molecules still be a big challenge in the solution‐processed method.To this end,chemical modification provides an effective solution‐processed strategy to construct donor and acceptor systems.Here,the C60‐pentacene is assembled into controllable flower‐like superstructures by the surface grafting method.It is found that the nanofeatures of the microflowers could be regulated by temperature,resulting in dense‐flakes morphology at room temperature and loose flakes at high temperatures.Furthermore,the dense‐flakes microflowers structures with less mass but better crystalline structure exhibit better optoelectronic properties.Our results reveal an effective control on the nanofeatures of the self‐assembled fullerenes complex super-structures and their role for the optoelectronic performance,which may promote the exploring of fullerene superstructures as photodetectors.
文摘This paper investigates the impact of differential foundation settlement on the reliability of bridge superstructure based on loads and resistances statistical properties in Missouri State.Maximum deterministic differential settlement is often used in current AASHTO LRFD(load and resistance factored design)specification.However,the expected foundation settlement is quite different from the actual settlement due to the soil’s large variability.Therefore,it makes sense to consider settlement as a random variable.In this paper,a lognormal distribution with coefficient of variation of 0.25 of random settlement is considered in reliability analysis based on limited previous studies.Dead and live loads are modeled as random variables with normal and Gumbel Type I distributions,respectively.Considering the regional traffic condition on Missouri roadways,the live load effect on existing bridges based on weight-in-motion data is also investigated.The calibrated resistance statistical properties such as bias and COV(coefficient of variance)are used for reliability analysis.Total 14 existing bridges based on Strength I Limit State are analyzed.Since no differential settlement is considered in the past designed bridges in Missouri,small differential settlement can significantly reduce the reliability indices of the superstructure,depending upon the span length and rigidity of the girder.The analysis results also show that the reliability of existing steel-girder bridges is consistently higher than prestressed concrete and solid slab bridges;the shorter and stiffer the spans,the more significant the settlement’s effect on the reliability of bridge superstructures;As the span length ratio becomes less than 0.75,the girder and solid slab bridges’reliability drops significantly at small settlements.
文摘As a distinct type of nanocapsules,hollow superstructures of inorganic nanoparticles have attracted increasing attention due to their controllable permeability,convenient functionalization,and efficient surface utilization.Conventionally,they are produced by assembling nanoparticles against expensive sacrificial templates.Herein,a general emulsion-based method is reported to assemble colloidal nanoparticles into submicron hollow superstructures,involving first co-assembly of colloidal nanoparticles with organic additives to form clusters,then overcoating the clusters with a polymer shell,and finally removing the organic additives and re-dispersing nanoparticles by exposing to a good solvent.The key to the success of this process is the re-assembly of nanoparticles against the polymer shells as driven by the capillary force during solvent evaporation,producing hollow superstructures.Such a space-confined assembly process can be well controlled by choice of solvents and their evaporation rates.This general technique provides an open and low-cost platform for creating hollow superstructures of various inorganic nanoparticles,offering many opportunities for exploring unique applications that can take advantage of the collective properties of the constituent nanoparticles and the permeable nanoshell structures.
基金the National Natural Science Foundation of China (Nos.51872030,51631001,21643003,51702016,and 51501010)Fundamental Research Funds for the Central Universities and Beijing Institute of Technology Research Fund Program for Young Scholars and ZDKT18-01 fund from State Key Laboratory of Explosion Science and Technology (Beijing Institute of Technology).We acknowledge critical and quantity of testing work supported by Beijing Zhongkebaice Technology Service Co., Ltd.
文摘Utilizing vacuum-tuned-atmosphere induced dip coating method,we achieve the cross-dimensional macroscopic diverse self-assemblies by using one building block with one chemical functionality.Coordinated modulating the vacuum degree,colloid concentration and evaporation atmosphere,Au@Ag core/shell nanocubes (NCs) can controllably assemble into diverse multi-dimensional superstructures.Under 0.08 MPa,we obtained the two-dimensional (2D) stepped superstructures with continuously tunable step width.In addition,we generated a series of tailorable nanoscale-roughened 2D Au@Ag NCs superstructures at 0.04 MPa,which exhibited the label-free ultrasensitive SERS detection for the different mutants of IAPP8-37 proteins.Under 0.01 MPa,we obtained the cross-dimensional tailorable Au@Ag NCs assemblies from random to macroscale 2D and three-dimensional (3D) densest superstructures by adjusting the capping ligand-environmental molecule interactions.This is a flexible method to generate as-prepared Au@Ag core/shell NCs into well-defined macroscopic diverse superstructures and to promote the exploitation into biological applications.
基金supported by the National Natural Science Foundation of China(Nos.NSFC-U1904215 and 21671170)the Topnotch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)+1 种基金Program for Young Changjiang Scholars of the Ministry of Education,China(No.Q2018270)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Hierarchical superstructures assembled by nanosheets can effectively prevent aggregation of nanosheets and improve performance in energy storage.Therefore,we proposed a facile hydrothermal method to obtain three-dimensional(3D)superstructure assembled by nanosheets.We found that the ratio of Co^(2+)/HMTA affected the morphology of the samples,and the 3D hierarchical structures of are obtained while the ratio of Co^(2+)/HMTA is 12:25.The hierarchical structures with sufficient interior space preserves the original sheet-like dimensional components and results in sufficient active sites and efficient mass diffusion.Hence,the 3D Co_(2)V_(2)O_(7)·nH_(2)O hierarchical structure exhibits good rate capability and high stability while as electrode materials.Meanwhile,when power density is 745.13 W/kg,the assembled CVO-2//AC shows an energy density of 47.7 Wh/kg.The work displays a facile method for fabrication of 3D superstructure assembled by 2D nanosheets that can be applied in energy storage.