Melting of crystalline material is a common physical phenomenon,yet it remains elusive owing to the diversity in physical pictures.In this work,we proposed a deep learning architecture to learn the physical states(sol...Melting of crystalline material is a common physical phenomenon,yet it remains elusive owing to the diversity in physical pictures.In this work,we proposed a deep learning architecture to learn the physical states(solid-or liquidphase)from the atomic trajectories of the bulk crystalline materials with four typical lattice types.The method has ultrahigh accuracy(higher than 95%)for the classification of solid-liquid atoms during the phase transition process and is almost insensitive to temperature.The atomic physical states are identified from atomic behaviors without considering any characteristic threshold parameter,which yet is necessary for the classical methods.The phase transition of bulk crystalline materials can be correctly predicted by learning from the atomic behaviors of different materials,which confirms the close correlation between atomic behaviors and atomic physical states.These evidences forecast that there should be a more general undiscovered physical quantity implicated in the atomic behaviors and elucidate the nature of bulk crystalline melting.展开更多
Cementitious capillary crystalline waterproof materials(CCCW for short)offer durability and excellent waterproofing properties,making them a popular option for building waterproofing.Some scholars have studied the pro...Cementitious capillary crystalline waterproof materials(CCCW for short)offer durability and excellent waterproofing properties,making them a popular option for building waterproofing.Some scholars have studied the proportioning of such materials.However,these studies lack the relationship between the impermeability pressure of mortar and the components,and the mechanism of action is somewhat debatable.Therefore,we adopted a two-step method in our experiments.Firstly,we screened out the components that significantly impact impermeability from a variety of active components by orthogonal test.We then optimized the design of the active group ratio using the simplex lattice method.Lastly,we conducted a performance test of the optimal ratio and explored the waterproofing mechanism of homemade CCCW.展开更多
Metal-containing crystalline porous materials(CPMs)are gaining popularity in heterogeneous catalysis because of their highly crystalline and porous systems,and their excellent chemical tunability.Modification of the m...Metal-containing crystalline porous materials(CPMs)are gaining popularity in heterogeneous catalysis because of their highly crystalline and porous systems,and their excellent chemical tunability.Modification of the metal species and framework structure permits them to have greater activity,selectivity,and stability over other materials.An in-depth understanding of the complex nature of metal active sites in CPMs is essential for revealing the structure-performance relationships and directing the rational design of such catalysts.Compared to conventional characterization techniques,the rapid development of X-ray absorption spectroscopy(XAS)has provided element-and site-specific deep insights into the electronic and structural information of metal species in CPMs.As such,this review begins by summarizing novel XAS techniques and analysis methods in accurately obtaining such data.Next,the combination of XAS with other high-level characterization methods into disclosing the configuration of active sites in metalcontaining CPMs is presented.Then,the utilization of theory-assisted XAS data analysis in examining complex metal-containing CPM catalysts is discussed.Afterwards,advanced in-situ/operando XAS studies into revealing the working sites in metal-containing CPMs under catalytic conditions are highlighted.We conclude by outlining the future challenges and prospects of XAS measurements,data analyses,and in-situ/operando setups in advancing the study of metal-in-CPM catalysts.展开更多
Theoretical and experimental research has been performed on the interaction curves and stress paths of crystalline polymeric materials PE and POM under tensile-torsional stress with a linearly intensifying model and i...Theoretical and experimental research has been performed on the interaction curves and stress paths of crystalline polymeric materials PE and POM under tensile-torsional stress with a linearly intensifying model and in terms of the yield points undergoing Von Mises criterion.展开更多
The Ginzbury-Landau theory for bainitic transformation was devised, which contains two first-order phase transformations, one being reconstructive represented by the diffusional proeutectoidal precipitation of ferrite...The Ginzbury-Landau theory for bainitic transformation was devised, which contains two first-order phase transformations, one being reconstructive represented by the diffusional proeutectoidal precipitation of ferrite, and the other the displacive transformation. It provides a coupled mechanism for the formation of bainite. With the numerical simulation results, a diffusion-induced nucleation and a diffusion-accompanied growth of displacive transformation were suggested. This theory can be helpful to over- throw the thermodynamic difficulty of displacive transformation above the Ms temperature, and also helpful to understand the Bs temperature, the partial supersaturation, the single variation of bainitic carbides, and the incomplete-reaction phenomenon of bainitic transformation, etc..展开更多
The nuclear fuel cycle inevitably generates a large amount of radioactive waste liquid,which will pose a serious threat to the ecological environment and human health.Ion exchange method has received wide attention fo...The nuclear fuel cycle inevitably generates a large amount of radioactive waste liquid,which will pose a serious threat to the ecological environment and human health.Ion exchange method has received wide attention for its easy operation,low cost and no secondary pollution.However,the effective removal of radioactive ions from complex solutions still remains a serious challenge due to their environmental mobility and radiotoxicity.We have developed an efficient strategy to construct crystalline ion-exchange materials by inducing layered or three-dimensional microporous anionic frameworks by organic cations that can be effectively exchanged by radioactive metal ions.This type of materials can be applied effectively to the removal of radioactive ions from complex solutions and the removal mechanism has been deeply clarified by means of single crystal structure analyses,theoretical calculations,etc.This review summarizes our recent progress in the study of synthesis,structures and properties of radioactive ion removals for such type of crystalline ion-exchange materials.展开更多
Recently,C568 has emerged as a new carbon allotrope,which shows semiconducting properties with a band gap around 1 eV and has attracted much attention.In this work,the external strain effects on the electronic propert...Recently,C568 has emerged as a new carbon allotrope,which shows semiconducting properties with a band gap around 1 eV and has attracted much attention.In this work,the external strain effects on the electronic properties of C568 have been studied theoretically through first-principle calculations.The numerical results show that while in-plane uniaxial and biaxial strains both reduces the band gap of C568 in case of tensile strain,their effects are quite different in the case of compressive strain.With increasing compressive uniaxial strain,the band gap of C568 first increases,and then dramatically decreases.In contrast,the application of compressive biaxial strain up to -10% only leads to a slight increase of band gap.Moreover,an indirect-todirect gap transition can be realized under both types of compressive strain.The results also show that the optical anisotropy of C568 can be induced under uniaxial strain,while biaxial strain does not cause such an effect.These results indicate good strain tunability of the band structure of C568,which could be helpful for the design and optimization of C568-based nanodevices.展开更多
Polyhedral shapes can be found in crystalline materials ranging from macroscopic natural mineral solids to microscopic or nanoscopic particles. These shapes originate from the crystallographic properties of the consti...Polyhedral shapes can be found in crystalline materials ranging from macroscopic natural mineral solids to microscopic or nanoscopic particles. These shapes originate from the crystallographic properties of the constituting material, and the outer shape depends on several unique habit planes. In this study, polyhedral crystal growth was simulated considering the surface energy and crystallographic characteristics. A series of polyhedrons, including cube, truncated hexahedron, cuboctahedron, truncated octahedron, and regular octahedron, was targeted. First, the polyhedron’s static surface energy and dynamic energy variation during crystal growth were computed. Then, the crystal-growth process was simulated based on the energy minimization policy. Interestingly, when the simulation began with truncated hexahedral nucleus, the shape changed to a cuboctahedron;however, a certain type of truncated octahedron was obtained when starting with different types of truncated octahedrons. In addition, once converged cuboctahedron abruptly changed the shape to a truncated octahedron as the crystal became larger. These results were supported by the static and dynamic energy curves. Furthermore, the method was applied to different materials by assuming virtual parameters, yielding various morphologies.展开更多
The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of ce...The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of cement） and CCCW（cementitious capillary crystalline waterproofing materials,4% by the weight of cement） were studied.The experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation phenomena.The percolation threshold was about 20%.A clear piezoresistive effect was observed in CFGCC with 1wt% of carbon fibers,20wt% or 30wt% of graphite powders under uniaxial compressive tests,indicating that this type of smart composites was a promising candidate for strain sensing.The measured gage factor （defined as the fractional change in resistance per unit strain） of CFGCC with graphite content of 20wt% and 30wt% were 37 and 22,respectively.With the addition of CCCW,the mechanical properties of CFGCC were improved,which benefited CFGCC piezoresistivity of stability.展开更多
Aggregation-induced emission-based luminogens(AIEgens)have aroused enormous interest due to their unique high fluorescence in a condensed state.To further explore their potential applications,such as chemical monitori...Aggregation-induced emission-based luminogens(AIEgens)have aroused enormous interest due to their unique high fluorescence in a condensed state.To further explore their potential applications,such as chemical monitoring,immobilization of AIE molecules has been widely studied with a variety of supports.Crystalline porous materials,such as metal-organic frameworks,covalent organic frameworks,hydrogen-bonded organic framework,and organic cages,demonstrate well-controlled structures,large surface areas,and promising stabilities,thus providing a perfect platform for AIE agents loading.Outstanding chemical sensing performances are achieved based on these AIE-active crystalline porous materials,such as high sensitivity,short response time,selective identification,and high recyclability,which provide a new alternative to readily detect various hazardous molecules.Furthermore,precise structures of AIEgen-based crystalline porous materials offer an easy way to investigate detection mechanisms.This mini-review will provide a brief overview of AIEgen-based crystalline porous materials for detection and then address how to improve sensing performances remarkably.展开更多
The surfaces and refractive index of crystalline lens play an important role in the optical performance of human eye. On the basis of two eye models, which are widely applied at present, the effect of lens surfaces an...The surfaces and refractive index of crystalline lens play an important role in the optical performance of human eye. On the basis of two eye models, which are widely applied at present, the effect of lens surfaces and its refractive index distribution on optical imaging is analyzed with the optical design software ZEMAX （Zemax Development Co., San Diego, USA）. The result shows that good image quality can be provided by the aspheric lens surfaces or （and） the gradient-index （GRIN） distribution. It has great potential in the design of intraocular lens （IOL）. The eye models with an intraocular implantation are presented.展开更多
In the past two decades, organic solar cells （OSCs） have at- tracted significant attention owing to their merits of achieving light-weight, flexible, low-cost devices [1,2]. Ternary OSC as an efficient way to improv...In the past two decades, organic solar cells （OSCs） have at- tracted significant attention owing to their merits of achieving light-weight, flexible, low-cost devices [1,2]. Ternary OSC as an efficient way to improve the power conversion efficiencies （PCEs） of OSCs has inspired great interest from researchers to investigate ternary OSCs and result in many efficient de- vices. Ternary OSCs allow collecting high- and low-energy photons by separated semiconductors in a single active layer to minimize the thermalization loss and broaden absorption range to improve the performance of OSCs. However, most reported ternary OSCs only have active layer of about 100 nm in thickness.展开更多
Self-assembly of predesigned chiral molecules to form structurally diverse functional materials has been one of the most exciting recent developments in materials science and nanotechnology over the past decade.Partic...Self-assembly of predesigned chiral molecules to form structurally diverse functional materials has been one of the most exciting recent developments in materials science and nanotechnology over the past decade.Particularly,the rationally designed chiral supermolecules and their hierarchical assemblies result in superior microenvironments,in which they interact distinctly with molecularly asymmetric guests for enantiospecific recognition.The chemistry of chiral supermolecule-based materials(CSMs)has become a lively research topic,and thus this review seeks to shed light on a range of synthetic CSMs at differing length scales developed in the past 5 years,with emphasis on the representative work from China.This review includes cavity-containing chiral supermolecules,chiral polymers,and chiral crystalline materials,aiming to tackle important issues from their design,synthesis,and structure to cutting-edge applications.This,in turn,allows for fundamental understanding of the transfer,amplification,and functional expression of chirality from the molecular to the supramolecular to the macroscopic scale.Finally,we provide perspectives on the promises,opportunities,and key challenges for the future development of useful chiral functional materials.展开更多
Developing new low-cost and efficient proton-conducting materials remains an attractive and challenging task.Herein,sodium molybdate dihydrate is used as the source of molybdenum,mixed with transition metal chloride a...Developing new low-cost and efficient proton-conducting materials remains an attractive and challenging task.Herein,sodium molybdate dihydrate is used as the source of molybdenum,mixed with transition metal chloride and 2-methylimidazole(2-MI),using the "one-pot method" to synthesize two crystalline proton conducting materials based on {P4Mo6} units:H14[C4H6N2]2[M(H_(2)O)5][M(H_(2)O)_(2)]_(2){M[(PO_(3))_(3)(PO_(4))Mo_(6)O_(15)]_(2)}·4H_(2)O(M=Co and Fe)(1-2).Different from the common{P4Mo_(6)},we use H3PO3to adjust the pH value,resulting in two different coordination modes of P atoms in the crystal structure.The structure is expanded into three-dimensional network by metal ions.At 75℃ and 98% relative humidity,the proton conductivity of compounds 1 and 2 are 1.33 ×10^(-2)S·cm^(-1)and 1.03×10^(-2)S·cm^(-1),respectively.The high proton conductivity is mainly attributed to the free state of 2-methylimidazole as the proton carrier,which has a fast migration rate.At the same time,2-methylimidazole,coordination water,and {P4Mo6} anion form a hydrogen bond network to provide multiple pathways for the transmission of protons.展开更多
An active area of MGI(Materials Genome Initiative)/MGE(Materials Genome Engineering)is to accelerate the development of new materials by means of active learning and“digital trial-error”using a prediction model of m...An active area of MGI(Materials Genome Initiative)/MGE(Materials Genome Engineering)is to accelerate the development of new materials by means of active learning and“digital trial-error”using a prediction model of material property.Machine learning methods have widely been employed for predicting crystalline materials properties with crystal graph neural networks(CGNN).The prediction accuracy of the state-of-the-art(SOTA)CGNN models based on big models and big data is generally higher.However,for the development of some classes of materials,the datasets obtained by experiments are usually lacking due to costly experiments and measurement costs.The lack of datasets will impact the accuracy of CGNN models and may result in overfitting during training models.This paper proposes a simplified crystal graph convolutional neural network(S-CGCNN)which possesses higher prediction accuracy while reducing the vast amount of train datasets and computation costs.The S-CGCNN model has successfully predicted properties of crystalline materials,such as piezoelectric materials and dielectric materials,and increased the prediction accuracy up to 12%-20%than existing SOTA CGNN models.Furthermore,the distribution map between properties and compositions of materials has been built to screen the latent space of candidate materials efficiently by principal component analysis.展开更多
In this Letter, new concepts of fluorescence phase-change materials and fluorescence phase-change multilevel recording are proposed. High-contrast fluorescence between the amorphous and crystalline states is achieved ...In this Letter, new concepts of fluorescence phase-change materials and fluorescence phase-change multilevel recording are proposed. High-contrast fluorescence between the amorphous and crystalline states is achieved in nickel- or bismuth-doped Ge;Sb;Te;phase-change memory thin films. Opposite phase-selective fluorescence effects are observed when different doping ions are used. The fluorescence intensity is sensitive to the crystallization degree of the films. This characteristic can be applied in reconfigurable multi-state memory and other logic devices. It also has likely applications in display and data visualization.展开更多
Photoluminescence （PL） conversion of Si nanoparticles by absorbing ultraviolet （UV） lights and emitting visible ones has been used to improve the efficiency of crystalline Si solar cells. Si nanoparticle thin film...Photoluminescence （PL） conversion of Si nanoparticles by absorbing ultraviolet （UV） lights and emitting visible ones has been used to improve the efficiency of crystalline Si solar cells. Si nanoparticle thin films are prepared by pulverizing porous Si in ethanol and then mixing the suspension with a SiO2 sol-gel （SOG）. This SOG is spin-deposited onto the surface of the Si solar cells and dries in air. The short-circuit current as a function of Si nanoparticle concentration is investigated under UV illumination. The maximal increase is found at a Si concentration of 0.1 mg/mL. At such concentration and under the irradiation of an AM0 solar simulator, the photoelectric conversion efficiency of the crystalline Si solar cell is relatively increased by 2.16% because of the PL conversion.展开更多
The Zn1-xMgxO thin films were deposited on sapphire substrates by reactive electron beam evaporation deposition （REBED）. The X-ray diffraction （XRD） measurement demonstrates that these films undergo phase transiti...The Zn1-xMgxO thin films were deposited on sapphire substrates by reactive electron beam evaporation deposition （REBED）. The X-ray diffraction （XRD） measurement demonstrates that these films undergo phase transition from hexagonal to cubic with increasing the Mg concentration. Absorption coefficients at 532 nm of the samples were obtained from the absorption spectra. Using optical Kerr effect, the thirdorder susceptibilities of the ternary films over a wide range of Mg concentrations were determined. The magnitude of X^（3） of the ternary Zn1-xMgxO films is order of 10^-11 esu at λ = 532 nm. The sample with phase mixture of both hexagonal and cubic structures shows the largest third-order susceptibility. The difference observed in the magnitude of X^（3） of Zn1-xMgxO films is attributed to the different microstructures of the ternary films, such as crystalline phase separation and crystal grains that enhance stimulated scattering.展开更多
Photofunctional materials with room-temperature phosphorescence（RTP）commonly appeared in expensive metal-coordination complexes and rare-earth-based compounds.Recently,the metal-free organic RTP materials have been ...Photofunctional materials with room-temperature phosphorescence（RTP）commonly appeared in expensive metal-coordination complexes and rare-earth-based compounds.Recently,the metal-free organic RTP materials have been paid growing attention from scientific community because of the ease of molecular design,low cost as well as potential applications in molecular switches,chemical sensors and biological imaging.To date,efficient RTP materials with high quantum yield are still very limited due to the T_1-S_0 spinforbidden process and weak spin-orbital coupling.Current mechanism based on crystallization-induced or aggregationinduced phosphorescence may serve as an effective way to enhance the RTP[1,2];展开更多
基金Project supported by the China Postdoctoral Science Foundation(Grant No.2019M663935XB)the Natural Science Foundation of Shaanxi Province,China(Grant No.2019JQ-261)the National Natural Science Foundation of China(Grant Nos.11802225 and 51878548)
文摘Melting of crystalline material is a common physical phenomenon,yet it remains elusive owing to the diversity in physical pictures.In this work,we proposed a deep learning architecture to learn the physical states(solid-or liquidphase)from the atomic trajectories of the bulk crystalline materials with four typical lattice types.The method has ultrahigh accuracy(higher than 95%)for the classification of solid-liquid atoms during the phase transition process and is almost insensitive to temperature.The atomic physical states are identified from atomic behaviors without considering any characteristic threshold parameter,which yet is necessary for the classical methods.The phase transition of bulk crystalline materials can be correctly predicted by learning from the atomic behaviors of different materials,which confirms the close correlation between atomic behaviors and atomic physical states.These evidences forecast that there should be a more general undiscovered physical quantity implicated in the atomic behaviors and elucidate the nature of bulk crystalline melting.
文摘Cementitious capillary crystalline waterproof materials(CCCW for short)offer durability and excellent waterproofing properties,making them a popular option for building waterproofing.Some scholars have studied the proportioning of such materials.However,these studies lack the relationship between the impermeability pressure of mortar and the components,and the mechanism of action is somewhat debatable.Therefore,we adopted a two-step method in our experiments.Firstly,we screened out the components that significantly impact impermeability from a variety of active components by orthogonal test.We then optimized the design of the active group ratio using the simplex lattice method.Lastly,we conducted a performance test of the optimal ratio and explored the waterproofing mechanism of homemade CCCW.
基金the National Natural Science Foundation of China(grant no.22301057)the financial support by the Natural Science Foundation of Hebei Province(grant no.B2023201065)+4 种基金Hebei University High-level Talent Research Program(grant no.521100223025)Y.L.thanks the funding from the National Natural Science Foundation of China(grant no.22305060)Hebei University High-level Talent Research Program(grant no.521100222060)P.Z.acknowledges the financial support from an Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery GrantA.G.W.thanks financial support from an NSERC Canada Graduate Scholarships-Doctoral Program(CGS-D)scholarship.
文摘Metal-containing crystalline porous materials(CPMs)are gaining popularity in heterogeneous catalysis because of their highly crystalline and porous systems,and their excellent chemical tunability.Modification of the metal species and framework structure permits them to have greater activity,selectivity,and stability over other materials.An in-depth understanding of the complex nature of metal active sites in CPMs is essential for revealing the structure-performance relationships and directing the rational design of such catalysts.Compared to conventional characterization techniques,the rapid development of X-ray absorption spectroscopy(XAS)has provided element-and site-specific deep insights into the electronic and structural information of metal species in CPMs.As such,this review begins by summarizing novel XAS techniques and analysis methods in accurately obtaining such data.Next,the combination of XAS with other high-level characterization methods into disclosing the configuration of active sites in metalcontaining CPMs is presented.Then,the utilization of theory-assisted XAS data analysis in examining complex metal-containing CPM catalysts is discussed.Afterwards,advanced in-situ/operando XAS studies into revealing the working sites in metal-containing CPMs under catalytic conditions are highlighted.We conclude by outlining the future challenges and prospects of XAS measurements,data analyses,and in-situ/operando setups in advancing the study of metal-in-CPM catalysts.
文摘Theoretical and experimental research has been performed on the interaction curves and stress paths of crystalline polymeric materials PE and POM under tensile-torsional stress with a linearly intensifying model and in terms of the yield points undergoing Von Mises criterion.
文摘The Ginzbury-Landau theory for bainitic transformation was devised, which contains two first-order phase transformations, one being reconstructive represented by the diffusional proeutectoidal precipitation of ferrite, and the other the displacive transformation. It provides a coupled mechanism for the formation of bainite. With the numerical simulation results, a diffusion-induced nucleation and a diffusion-accompanied growth of displacive transformation were suggested. This theory can be helpful to over- throw the thermodynamic difficulty of displacive transformation above the Ms temperature, and also helpful to understand the Bs temperature, the partial supersaturation, the single variation of bainitic carbides, and the incomplete-reaction phenomenon of bainitic transformation, etc..
基金supported by the National Natural Science Foundation of China(Nos.22076185,21771183,21373223,21221001,21171164,20873149 and 20771102)the 973 programs(Nos.2014CB845603,2012CB821702 and 2006CB932904)+3 种基金the Natural Science Foundation of Fujian Province(Nos.2020J06033,2018J01027,2010J01056)FJIRSM&IUE Joint Research Fund(No.RHZX-2018-005)Chunmiao project of Haixi institute of Chinese Academy of Sciences(CMZX-2014-001)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2011220)。
文摘The nuclear fuel cycle inevitably generates a large amount of radioactive waste liquid,which will pose a serious threat to the ecological environment and human health.Ion exchange method has received wide attention for its easy operation,low cost and no secondary pollution.However,the effective removal of radioactive ions from complex solutions still remains a serious challenge due to their environmental mobility and radiotoxicity.We have developed an efficient strategy to construct crystalline ion-exchange materials by inducing layered or three-dimensional microporous anionic frameworks by organic cations that can be effectively exchanged by radioactive metal ions.This type of materials can be applied effectively to the removal of radioactive ions from complex solutions and the removal mechanism has been deeply clarified by means of single crystal structure analyses,theoretical calculations,etc.This review summarizes our recent progress in the study of synthesis,structures and properties of radioactive ion removals for such type of crystalline ion-exchange materials.
文摘Recently,C568 has emerged as a new carbon allotrope,which shows semiconducting properties with a band gap around 1 eV and has attracted much attention.In this work,the external strain effects on the electronic properties of C568 have been studied theoretically through first-principle calculations.The numerical results show that while in-plane uniaxial and biaxial strains both reduces the band gap of C568 in case of tensile strain,their effects are quite different in the case of compressive strain.With increasing compressive uniaxial strain,the band gap of C568 first increases,and then dramatically decreases.In contrast,the application of compressive biaxial strain up to -10% only leads to a slight increase of band gap.Moreover,an indirect-todirect gap transition can be realized under both types of compressive strain.The results also show that the optical anisotropy of C568 can be induced under uniaxial strain,while biaxial strain does not cause such an effect.These results indicate good strain tunability of the band structure of C568,which could be helpful for the design and optimization of C568-based nanodevices.
文摘Polyhedral shapes can be found in crystalline materials ranging from macroscopic natural mineral solids to microscopic or nanoscopic particles. These shapes originate from the crystallographic properties of the constituting material, and the outer shape depends on several unique habit planes. In this study, polyhedral crystal growth was simulated considering the surface energy and crystallographic characteristics. A series of polyhedrons, including cube, truncated hexahedron, cuboctahedron, truncated octahedron, and regular octahedron, was targeted. First, the polyhedron’s static surface energy and dynamic energy variation during crystal growth were computed. Then, the crystal-growth process was simulated based on the energy minimization policy. Interestingly, when the simulation began with truncated hexahedral nucleus, the shape changed to a cuboctahedron;however, a certain type of truncated octahedron was obtained when starting with different types of truncated octahedrons. In addition, once converged cuboctahedron abruptly changed the shape to a truncated octahedron as the crystal became larger. These results were supported by the static and dynamic energy curves. Furthermore, the method was applied to different materials by assuming virtual parameters, yielding various morphologies.
基金Funded by the National Natural Science Foundation of China(No.50878170 and No. 10672128)
文摘The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of cement） and CCCW（cementitious capillary crystalline waterproofing materials,4% by the weight of cement） were studied.The experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation phenomena.The percolation threshold was about 20%.A clear piezoresistive effect was observed in CFGCC with 1wt% of carbon fibers,20wt% or 30wt% of graphite powders under uniaxial compressive tests,indicating that this type of smart composites was a promising candidate for strain sensing.The measured gage factor （defined as the fractional change in resistance per unit strain） of CFGCC with graphite content of 20wt% and 30wt% were 37 and 22,respectively.With the addition of CCCW,the mechanical properties of CFGCC were improved,which benefited CFGCC piezoresistivity of stability.
基金National Natural Science Foundation of China,Grant/Award Numbers:21571079,21621001,21390394,21571076,21571078″111″project,Grant/Award Numbers:B07016,B17020JLU Science and Technology Innovative Research Team。
文摘Aggregation-induced emission-based luminogens(AIEgens)have aroused enormous interest due to their unique high fluorescence in a condensed state.To further explore their potential applications,such as chemical monitoring,immobilization of AIE molecules has been widely studied with a variety of supports.Crystalline porous materials,such as metal-organic frameworks,covalent organic frameworks,hydrogen-bonded organic framework,and organic cages,demonstrate well-controlled structures,large surface areas,and promising stabilities,thus providing a perfect platform for AIE agents loading.Outstanding chemical sensing performances are achieved based on these AIE-active crystalline porous materials,such as high sensitivity,short response time,selective identification,and high recyclability,which provide a new alternative to readily detect various hazardous molecules.Furthermore,precise structures of AIEgen-based crystalline porous materials offer an easy way to investigate detection mechanisms.This mini-review will provide a brief overview of AIEgen-based crystalline porous materials for detection and then address how to improve sensing performances remarkably.
基金the National Na-ture Science Foundation of China (No.60678048)the Nature Science Foundations of Jiangsu Province (No.BK2007207 and BS2007061).
文摘The surfaces and refractive index of crystalline lens play an important role in the optical performance of human eye. On the basis of two eye models, which are widely applied at present, the effect of lens surfaces and its refractive index distribution on optical imaging is analyzed with the optical design software ZEMAX （Zemax Development Co., San Diego, USA）. The result shows that good image quality can be provided by the aspheric lens surfaces or （and） the gradient-index （GRIN） distribution. It has great potential in the design of intraocular lens （IOL）. The eye models with an intraocular implantation are presented.
文摘In the past two decades, organic solar cells （OSCs） have at- tracted significant attention owing to their merits of achieving light-weight, flexible, low-cost devices [1,2]. Ternary OSC as an efficient way to improve the power conversion efficiencies （PCEs） of OSCs has inspired great interest from researchers to investigate ternary OSCs and result in many efficient de- vices. Ternary OSCs allow collecting high- and low-energy photons by separated semiconductors in a single active layer to minimize the thermalization loss and broaden absorption range to improve the performance of OSCs. However, most reported ternary OSCs only have active layer of about 100 nm in thickness.
基金financially supported by the major research plan“Precise Construction of Multilevel Chiral Substances”of the National Natural Science Foundation of China(grant nos.9195600 and 92256303).
文摘Self-assembly of predesigned chiral molecules to form structurally diverse functional materials has been one of the most exciting recent developments in materials science and nanotechnology over the past decade.Particularly,the rationally designed chiral supermolecules and their hierarchical assemblies result in superior microenvironments,in which they interact distinctly with molecularly asymmetric guests for enantiospecific recognition.The chemistry of chiral supermolecule-based materials(CSMs)has become a lively research topic,and thus this review seeks to shed light on a range of synthetic CSMs at differing length scales developed in the past 5 years,with emphasis on the representative work from China.This review includes cavity-containing chiral supermolecules,chiral polymers,and chiral crystalline materials,aiming to tackle important issues from their design,synthesis,and structure to cutting-edge applications.This,in turn,allows for fundamental understanding of the transfer,amplification,and functional expression of chirality from the molecular to the supramolecular to the macroscopic scale.Finally,we provide perspectives on the promises,opportunities,and key challenges for the future development of useful chiral functional materials.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 21871042, 21471028, 21673098, and 21671036)Natural Science Foundation of Jilin Province (Grant No. 20200201083JC)+2 种基金Jilin Provincial Education Department (Grant No. JJKH20201169KJ)the Fundamental Research Funds for the Central Universities (Grant Nos. 2412015KJ012, 2412017BJ004)the support of the Jilin Provincial Department of Education。
文摘Developing new low-cost and efficient proton-conducting materials remains an attractive and challenging task.Herein,sodium molybdate dihydrate is used as the source of molybdenum,mixed with transition metal chloride and 2-methylimidazole(2-MI),using the "one-pot method" to synthesize two crystalline proton conducting materials based on {P4Mo6} units:H14[C4H6N2]2[M(H_(2)O)5][M(H_(2)O)_(2)]_(2){M[(PO_(3))_(3)(PO_(4))Mo_(6)O_(15)]_(2)}·4H_(2)O(M=Co and Fe)(1-2).Different from the common{P4Mo_(6)},we use H3PO3to adjust the pH value,resulting in two different coordination modes of P atoms in the crystal structure.The structure is expanded into three-dimensional network by metal ions.At 75℃ and 98% relative humidity,the proton conductivity of compounds 1 and 2 are 1.33 ×10^(-2)S·cm^(-1)and 1.03×10^(-2)S·cm^(-1),respectively.The high proton conductivity is mainly attributed to the free state of 2-methylimidazole as the proton carrier,which has a fast migration rate.At the same time,2-methylimidazole,coordination water,and {P4Mo6} anion form a hydrogen bond network to provide multiple pathways for the transmission of protons.
基金supported by the National Natural Science Foundation of China(No.52175284)the State Key Lab of Advanced Metals and Materials in University of Science and Technology Beijing(No.2021-ZD08).
文摘An active area of MGI(Materials Genome Initiative)/MGE(Materials Genome Engineering)is to accelerate the development of new materials by means of active learning and“digital trial-error”using a prediction model of material property.Machine learning methods have widely been employed for predicting crystalline materials properties with crystal graph neural networks(CGNN).The prediction accuracy of the state-of-the-art(SOTA)CGNN models based on big models and big data is generally higher.However,for the development of some classes of materials,the datasets obtained by experiments are usually lacking due to costly experiments and measurement costs.The lack of datasets will impact the accuracy of CGNN models and may result in overfitting during training models.This paper proposes a simplified crystal graph convolutional neural network(S-CGCNN)which possesses higher prediction accuracy while reducing the vast amount of train datasets and computation costs.The S-CGCNN model has successfully predicted properties of crystalline materials,such as piezoelectric materials and dielectric materials,and increased the prediction accuracy up to 12%-20%than existing SOTA CGNN models.Furthermore,the distribution map between properties and compositions of materials has been built to screen the latent space of candidate materials efficiently by principal component analysis.
基金partially supported by the National Natural Science Foundation of China(Nos.61178059,51472258,and 61137002)the National Basic Research Program of China(No.2013CBA01900)
文摘In this Letter, new concepts of fluorescence phase-change materials and fluorescence phase-change multilevel recording are proposed. High-contrast fluorescence between the amorphous and crystalline states is achieved in nickel- or bismuth-doped Ge;Sb;Te;phase-change memory thin films. Opposite phase-selective fluorescence effects are observed when different doping ions are used. The fluorescence intensity is sensitive to the crystallization degree of the films. This characteristic can be applied in reconfigurable multi-state memory and other logic devices. It also has likely applications in display and data visualization.
基金supported by the National Basic Research Program of China (No. 2010CB933703)the National Natural Science Foundation of China (No.60878044)
文摘Photoluminescence （PL） conversion of Si nanoparticles by absorbing ultraviolet （UV） lights and emitting visible ones has been used to improve the efficiency of crystalline Si solar cells. Si nanoparticle thin films are prepared by pulverizing porous Si in ethanol and then mixing the suspension with a SiO2 sol-gel （SOG）. This SOG is spin-deposited onto the surface of the Si solar cells and dries in air. The short-circuit current as a function of Si nanoparticle concentration is investigated under UV illumination. The maximal increase is found at a Si concentration of 0.1 mg/mL. At such concentration and under the irradiation of an AM0 solar simulator, the photoelectric conversion efficiency of the crystalline Si solar cell is relatively increased by 2.16% because of the PL conversion.
基金This work was supported by the National Natural Sci-ence Foundation of China under Grant No. 10174064and 50472058.
文摘The Zn1-xMgxO thin films were deposited on sapphire substrates by reactive electron beam evaporation deposition （REBED）. The X-ray diffraction （XRD） measurement demonstrates that these films undergo phase transition from hexagonal to cubic with increasing the Mg concentration. Absorption coefficients at 532 nm of the samples were obtained from the absorption spectra. Using optical Kerr effect, the thirdorder susceptibilities of the ternary films over a wide range of Mg concentrations were determined. The magnitude of X^（3） of the ternary Zn1-xMgxO films is order of 10^-11 esu at λ = 532 nm. The sample with phase mixture of both hexagonal and cubic structures shows the largest third-order susceptibility. The difference observed in the magnitude of X^（3） of Zn1-xMgxO films is attributed to the different microstructures of the ternary films, such as crystalline phase separation and crystal grains that enhance stimulated scattering.
文摘Photofunctional materials with room-temperature phosphorescence（RTP）commonly appeared in expensive metal-coordination complexes and rare-earth-based compounds.Recently,the metal-free organic RTP materials have been paid growing attention from scientific community because of the ease of molecular design,low cost as well as potential applications in molecular switches,chemical sensors and biological imaging.To date,efficient RTP materials with high quantum yield are still very limited due to the T_1-S_0 spinforbidden process and weak spin-orbital coupling.Current mechanism based on crystallization-induced or aggregationinduced phosphorescence may serve as an effective way to enhance the RTP[1,2];
