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Relationship between polyhedral structures formed by tangent planes of ellipsoidal particles and system sound velocity
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作者 Cheng-Bo Li Lin Bao Chuang Zhao 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第11期448-456,共9页
Internal polyhedral structures of a granular system can be investigated using the Voronoi tessellations.This technique has gained increasing recognition in research of kinetic properties of granular flows.For systems ... Internal polyhedral structures of a granular system can be investigated using the Voronoi tessellations.This technique has gained increasing recognition in research of kinetic properties of granular flows.For systems with mono-sized spherical particles,Voronoi tessellations can be utilized,while radial Voronoi tessellations are necessary for analyzing systems with multi-sized spherical particles.However,research about polyhedral structures of non-spherical particle systems is limited.We utilize the discrete element method to simulate a system of ellipsoidal particles,defined by the equation(x/a)^(2)+(y/1)^(2)+(z/1/a)^(2)=1,where a ranges from 1.1 to 2.0.The system is then dissected by using tangent planes at the contact points,and the geometric quantities of the resulting polyhedra in different shaped systems,such as surface area,volume,number of vertices,number of edges,and number of faces,are calculated.Meanwhile,the longitudinal and transverse wave velocities within the system are calculated with the time-of-flight method.The results demonstrate a strong correlation between the sound velocity of the system and the geometry of the dissected polyhedra.The sound velocity of the system increases with the increase in a,peaking at a=1.3,and then decreases as a continues to increase.The average volume,surface area,number of vertices,number of edges,and number of faces of the polyhedra decrease with the increase in sound velocity.That is,these quantities initially decrease with the increase in a,reaching minima at a=1.3,and then increase with further increase of a.The relationship between sound velocity and the geometric quantities of the dissected polyhedra can serve as a reference for acoustic material design. 展开更多
关键词 discrete element method Voronoi tessellation polyhedral structure sound velocity
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Utilizing a defective MgO layer for engineering multifunctional Co-MOF hybrid materials with tailored leaf-like and polyhedral structures for optimal electrochemical and photocatalytic activities
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作者 Mohammad Aadil Muhammad Ali Khan +1 位作者 Safira Ananda Repycha Mosab Kaseem 《Nano Materials Science》 EI CAS CSCD 2024年第5期548-564,共17页
The hybridization of metal-organic framework(MOF)with inorganic layers would lead to the discovery of novel hybrid materials that can provide a compelling strategy for enhancing its photocatalytic and electrochemical ... The hybridization of metal-organic framework(MOF)with inorganic layers would lead to the discovery of novel hybrid materials that can provide a compelling strategy for enhancing its photocatalytic and electrochemical response.In the present study,a highly efficient multifunctional hybrid material was developed by exploiting the defective layer formed on AZ31 Mg alloy through plasma electrolytic oxidation(PEO)as a nucleation and growth site for Co-MOF.The concentrations of the organic linker 2-Methylimidazole(2,MIm)and cobalt nitrate as a source of Co^(2+) ions were varied to control the growth of the obtained Co-MOF.Lower concentrations of the 2,MIm ligand favored the formation of leaf-like MOF structures through an anisotropic,two-dimensional growth,while higher concentrations led to rapid,isotropic nucleation and the creation of polyhedral Co-MOF structures.The sample characterized by polyhedral Co-MOF structures exhibited superior electrochemical stability,with the lowest corrosion current density(3.11×10^(-9) A/cm^(2))and the highest top layer resistance(2.34×10^(6)Ωcm^(2)),and demonstrated outstanding photocatalytic efficiency,achieving a remarkable 99.98%degradation of methylene blue,an organic pollutant,in model wastewater.To assess the active adsorption sites of the Co-MOF,density functional theory(DFT)was utilized.This study explores the changes in morphologies of the coatings of Co-MOF with the change of solution concentration to form coatings with enhanced properties on the metallic substrate,which could establish the groundwork for the development of next-generation multifunctional frameworks with diverse applications. 展开更多
关键词 Multifunctional layer MOF polyhedral structures Corrosion Photocatalytic activity
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Ratio of In-Sphere Volume to Polyhedron Volume of the Great Pyramid Compared to Selected Convex Polyhedral Solids 被引量:4
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作者 Hans Hermann Otto 《Journal of Applied Mathematics and Physics》 2021年第1期41-56,共16页
The architecture of the Great Pyramid at Giza is based on fascinating golden mean geometry. Recently the ratio of the in-sphere volume to the pyramid volume was calculated. One yields as result <em>R</em>&... The architecture of the Great Pyramid at Giza is based on fascinating golden mean geometry. Recently the ratio of the in-sphere volume to the pyramid volume was calculated. One yields as result <em>R</em><sub><em>V</em></sub> = π <span style="white-space:nowrap;"><span style="white-space:nowrap;">&#8901;</span></span> <em><em style="white-space:normal;">φ</em></em><sup>5</sup>, where <img src="Edit_83decbce-7252-44ed-a822-fef13e43fd2a.bmp" alt="" /> is the golden mean. It is important that the number <em>φ</em><sup>5</sup> is a fundamental constant of nature describing phase transition from microscopic to cosmic scale. In this contribution the relatively small volume ratio of the Great Pyramid was compared to that of selected convex polyhedral solids such as the <em>Platonic </em>solids respectively the face-rich truncated icosahedron (bucky ball) as one of <em>Archimedes</em>’ solids leading to effective filling of the polyhedron by its in-sphere and therefore the highest volume ratio of the selected examples. The smallest ratio was found for the Great Pyramid. A regression analysis delivers the highly reliable volume ratio relation <img src="Edit_79e766ce-5580-4ae0-a706-570e0f3f1bd8.bmp" alt="" />, where <em>nF</em> represents the number of polyhedron faces and b approximates the silver mean. For less-symmetrical solids with a unique axis (tetragonal pyramids) the in-sphere can be replaced by a biaxial ellipsoid of maximum volume to adjust the <em>R</em><sub><em>V</em></sub> relation more reliably. 展开更多
关键词 POLYHEDRON Great Pyramid Platonic Solids Volume-Area Ratio In-Sphere and In-Ellipsoid polyhedral Void Space Golden and Silver Mean
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Synthesis and Luminescent Property of Polycarbazole/Polyhedral Oligomeric Silsesquioxane Nanocomposites 被引量:1
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作者 ZHU Yu-fang ZHAO Jun-feng +1 位作者 WANG Xi LI Qi-fang 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2008年第5期570-574,共5页
Polyvinylcarbazole(PVK) composites containing organic-inorganic hybrid polyhedral oligomeric silse-squioxane(POSS) PVK-POSS were prepared by free radical polymerization. POSS monomers reacted with vinylcarbazole a... Polyvinylcarbazole(PVK) composites containing organic-inorganic hybrid polyhedral oligomeric silse-squioxane(POSS) PVK-POSS were prepared by free radical polymerization. POSS monomers reacted with vinylcarbazole and were completely dispersed at molecular level in PVK matrix and PVK-POSS nanocomposites display higher glass transition temperature(Tg) in comparison with neat PVK. Optical properties of PVK/POSS nanocomposites were investigated by UV-spectrum and PL-spectrum and the results show that the PVK-POSS nanoparticles have a good interface effect and improve color purity effectively. The maximum absorption wavelength bathochromically shifts gradually with the increasing of the content of POSS. The luminescent intensity becomes higher and higher with the increase of POSS content, and reaches its maximum luminescent intensity when the POSS content is 3% (mass fraction), while some POSS-rich nanoparticles are present in matrix when contents of POSS are beyond 5%. 展开更多
关键词 polyhedral oligomeric silsesquioxane LUMINESCENCE POLYVINYLCARBAZOLE NANOCOMPOSITE
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Delay-dependent robust H_∞control of convex polyhedral uncertain fuzzy systems 被引量:1
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作者 Gong Cheng Su Baoku 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第6期1191-1198,共8页
The robust H∞ control problem for a class of uncertain Takagi-Sugeno fuzzy systems with timevarying state delays is studied. The uncertain parameters are supposed to reside in a polytope. Based on the delay-dependent... The robust H∞ control problem for a class of uncertain Takagi-Sugeno fuzzy systems with timevarying state delays is studied. The uncertain parameters are supposed to reside in a polytope. Based on the delay-dependent Lyapunov functional method, a new delay-dependent robust H∞ fuzzy controller, which depends on the size of the delays and the derivative of the delays, is presented in term of linear matrix inequalities (LMIs). For all admissible uncertainties and delays, the controller guarantees not only the asymptotic stability of the system but also the prescribed H∞ attenuation level. In addition, the effectiveness of the proposed design method is demonstrated by a numerical example. 展开更多
关键词 robust H∞ control DELAY-DEPENDENT polyhedral uncertainty fuzzy systems
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Gregory Solid Construction for Polyhedral Volume Parameterization by Sparse Optimization
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作者 HU Chuan-feng LIN Hong-wei 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2019年第3期340-355,共16页
In isogeometric analysis,it is frequently required to handle the geometric models enclosed by four-sided or non-four-sided boundary patches,such as trimmed surfaces.In this paper,we develop a Gregory solid based metho... In isogeometric analysis,it is frequently required to handle the geometric models enclosed by four-sided or non-four-sided boundary patches,such as trimmed surfaces.In this paper,we develop a Gregory solid based method to parameterize those models.First,we extend the Gregory patch representation to the trivariate Gregory solid representation.Second,the trivariate Gregory solid representation is employed to interpolate the boundary patches of a geometric model,thus generating the polyhedral volume parametrization.To improve the regularity of the polyhedral volume parametrization,we formulate the construction of the trivariate Gregory solid as a sparse optimization problem,where the optimization objective function is a linear combination of some terms,including a sparse term aiming to reduce the negative Jacobian area of the Gregory solid.Then,the alternating direction method of multipliers(ADMM)is used to solve the sparse optimization problem.Lots of experimental examples illustrated in this paper demonstrate the effectiveness and efficiency of the developed method. 展开更多
关键词 Gregory solid polyhedral volume PARAMETRIZATION SPARSE OPTIMIZATION REGULARITY Isogeometric analysis
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Study of Flame Retardation of Polycarbonate Modified by Polyhedral Oligomeric Silsesquioxane and Caged Bicyclic Phosphate
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作者 蒋云芸 杨荣杰 《Journal of Beijing Institute of Technology》 EI CAS 2010年第4期480-486,共7页
The flame-retarded polycarbonate(PC) has been made with octaphenyl polyhedral silsesquioxane(OPS) and/or caged bicyclic phosphate(Trimer).Thermal gravimetric analysis(TGA),Fourier-transform infrared(FTIR),TG... The flame-retarded polycarbonate(PC) has been made with octaphenyl polyhedral silsesquioxane(OPS) and/or caged bicyclic phosphate(Trimer).Thermal gravimetric analysis(TGA),Fourier-transform infrared(FTIR),TGA-FTIR,limiting oxygen index(LOI),and mechanical tests have been employed to characterize the modified PC.The additives of OPS and Trimer in PC have been proved to be effective flame-retardants because of the synergistic interaction between the elements of P and Si.The role of OPS and Trimer in PC degradation are different:OPS participates in the charring of PC,while Trimer makes PC degrade in advance.In addition,OPS and Trimer induced obvious differences in the mechanical properties of PC. 展开更多
关键词 POLYCARBONATE flame retardancy polyhedral oligomeric silsesquioxane caged bicyclic phosphate
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Synthesis and characterization of poly(methyl methacrylate-co-polyhedral oligomeric silsesquioxane)hybrid nanocomposites
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作者 Ben Hong Yang Hong Yao Xu +1 位作者 Cun Li Shan Yi Guang 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第8期960-962,共3页
A novel poly(methyl methacrylate-co-polyhedral oligomeric silsesquioxane) hybrid nanocomposite was synthesized by free radical polymerization and characterized by 1H NMR, 29Si NMR, and TGA technologies. Compared wit... A novel poly(methyl methacrylate-co-polyhedral oligomeric silsesquioxane) hybrid nanocomposite was synthesized by free radical polymerization and characterized by 1H NMR, 29Si NMR, and TGA technologies. Compared with PMMA homopolymer, the nanocomposite has better thermal stability. 展开更多
关键词 Poly(methyl methacrylate) polyhedral silsesquioxane Nanoeomposite
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Modeling calving process of glacier with dilated polyhedral discrete element method
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作者 Lu Liu Ji Li +3 位作者 Qizhen Sun Chunhua Li Sue Cook Shunying Ji 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第7期159-169,共11页
Mass loss caused by glacier calving is one of the direct contributors to global sea level rise.Reliable calving laws are required for accurate modelling of ice sheet mass balance.Both continuous and discontinuous meth... Mass loss caused by glacier calving is one of the direct contributors to global sea level rise.Reliable calving laws are required for accurate modelling of ice sheet mass balance.Both continuous and discontinuous methods have been used for glacial calving simulations.In this study,the discrete element method(DEM)based on dilated polyhedral elements is introduced to simulate the calving process of a tidewater glacier.Dilated polyhedrons can be obtained from the Minkowski sum of a sphere and a core polyhedron.These elements can be utilized to generate a continuum ice material,where the interaction force between adjacent elements is modeled by constructing bonds at the joints of the common faces.A hybrid fracture model considering fracture energy is introduced.The viscous creep behavior of glaciers on long-term scales is not considered.By applying buoyancy and gravity to the modelled glacier,DEM results show that the calving process is caused by cracks which are initialized at the top of the glacier and spread to the bottom.The results demonstrate the feasibility of using the dilated polyhedral DEM method in glacier simulations,additionally allowing the fragment size of the breaking fragments to be counted.The relationship between crack propagation and internal stress in the glacier is analyzed during calving process.Through the analysis of the Mises stress and the normal stress between the elements,it is found that geometric changes caused by the glacier calving lead to the redistribution of the stress.The tensile stress between the elements is the main influencing factor of glacier ice failure.In addition,the element shape,glacier base friction and buoyancy are studied,the results show that the glacier model based on the dilated polyhedral DEM is sensitive to the above conditions. 展开更多
关键词 glacier calving discrete element method dilated polyhedral element bond and fracture model
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Synthesis and Characterization of a New Titanium-silicate Material Containing Cage-like Polyhedral Oligosilsesquioxane
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作者 DING Han-ming ZHANG Da-wei LI Jiang KONG Ai-guo SHAN Yong-kui 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2007年第4期388-390,共3页
A new titanium-silicate material was synthesized with cubic cage-like tetramethylammonium octasilicate and TiCl4 ethanol solution as precursors. The product was characterized by FTIR, ^29Si NMR, UV-Vis, and XRD. Struc... A new titanium-silicate material was synthesized with cubic cage-like tetramethylammonium octasilicate and TiCl4 ethanol solution as precursors. The product was characterized by FTIR, ^29Si NMR, UV-Vis, and XRD. Struc-tural and ingrediental analyses suggest that this material has a layered structure with cubic cage-like polyhedral oligo-silsesquioxane as building blocks and titanium as bridging atoms. 展开更多
关键词 polyhedral oligosilsesquioxane Synthesis Titanium-silicate material
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Fabrication of Layer-by-layer Films of Polyhedral Oligomeric Silsesquioxanes
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作者 XiaoMengWANG HanMingDING YongKuiSHAN MingYuanHE 《Chinese Chemical Letters》 SCIE CAS CSCD 2004年第10期1227-1229,共3页
Layer-by-layer (LBL) self-assembly method was used to fabricate siliceous ultrathin films by using polyhedral oligomeric silsesquioxanes as building blocks. Ammonium salt of octasilsesquioxane acid (OSi8) and poly(dia... Layer-by-layer (LBL) self-assembly method was used to fabricate siliceous ultrathin films by using polyhedral oligomeric silsesquioxanes as building blocks. Ammonium salt of octasilsesquioxane acid (OSi8) and poly(diallyldimethylammonium chloride) (PDDA) were alternately assembled onto CaF2 slide to form nanocomposite multilayers. Linear build-up of the LBL films was confirmed by UV-Vis spectroscopy. IR spectrum suggests existence of OSi8 and PDDA in the LBL films. Atomic force microscopic surface topography of the LBL films indicates the OSi8 covers the entire surface of the topmost layer and shows a granular morphology. 展开更多
关键词 polyhedral oligomeric silsesquioxanes layer-by-layer ultrathin films.
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Polyhedral symmetry and quantum mechanics
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作者 G. S. Anagnostatos 《Natural Science》 2014年第4期198-210,共13页
A thorough study of regular and quasi-regular polyhedra shows that the symmetries of these polyhedra identically describe the quantization of orbital angular momentum, of spin, and of total angular momentum, a fact wh... A thorough study of regular and quasi-regular polyhedra shows that the symmetries of these polyhedra identically describe the quantization of orbital angular momentum, of spin, and of total angular momentum, a fact which permits one to assign quantum states at the vertices of these polyhedra assumed as the average particle positions. Furthermore, if the particles are fermions, their wave function is anti-symmetric and its maxima are identically the same as those of repulsive particles, e.g., on a sphere like the spherical shape of closed shells, which implies equilibrium of these particles having average positions at the aforementioned maxima. Such equilibria on a sphere are solely satisfied at the vertices of regular and quasi-regular polyhedra which can be associated with the most probable forms of shells both in Nuclear Physics and in Atomic Cluster Physics when the constituent atoms possess half integer spins. If the average sizes of the constituent particles are known, then the average sizes of the resulting shells become known as well. This association of Symmetry with Quantum Mechanics leads to many applications and excellent results. 展开更多
关键词 SYMMETRY polyhedral SYMMETRY Angular Momentum and POLYHEDRA Nuclear Structure and SYMMETRY ISOMORPHIC SHELL Model SHELL Clustering in Nuclei Binding Energies RADII
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A Geometric Method for Generating Discrete Trace Transition System of a Polyhedral Invariant Hybrid Automaton
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作者 Sobhi Baniardalani Javad Askari 《Intelligent Control and Automation》 2012年第2期197-206,共10页
Supervisory control and fault diagnosis of hybrid systems need to have complete information about the discrete states transitions of the underling system. From this point of view, the hybrid system should be abstracte... Supervisory control and fault diagnosis of hybrid systems need to have complete information about the discrete states transitions of the underling system. From this point of view, the hybrid system should be abstracted to a Discrete Trace Transition System (DTTS) and represented by a discrete mode transition graph. In this paper an effective method is proposed for generating discrete mode transition graph of a hybrid system. This method can be used for a general class of industrial hybrid plants which are defined by Polyhedral Invariant Hybrid Automata (PIHA). In these automata there are no resetting maps, while invariant sets are defined by linear inequalities. Therefore, based on the continuity property of the state trajectories in a PIHA, the problem is reduced to finding possible transitions between all two adjacent discrete modes. In the presented method, the possibility and the direction of such transitions are detected only by computing the angle between the vector field and the normal vector of the switching surfaces. Thus, unlike the most other reachability methods, there is no need to solve differential equations and to do mapping computations. In addition, the proposed method, with some modifications can be applied for extracting Stochastic or Timed Discrete Trace Transition Systems. 展开更多
关键词 HYBRID System DISCRETE TRACE TRANSITION System polyhedral INVARIANT HYBRID Automata DISCRETE Mode TRANSITION Graph
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Discrete Element Modelling of Dynamic Behaviour of Rockfills forResisting High Speed Projectile Penetration 被引量:3
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作者 Tingting Zhao Y.T.Feng +2 位作者 Jie Zhang Zhihua Wang Zhiyong Wang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2021年第5期721-735,共15页
This paper presents a convex polyhedral based discrete element method for modelling the dynamic behaviour ofrockfills for resisting high speed projectile penetration. The contact between two convex polyhedra is define... This paper presents a convex polyhedral based discrete element method for modelling the dynamic behaviour ofrockfills for resisting high speed projectile penetration. The contact between two convex polyhedra is defined by theMinkowski overlap and determined by the GJK and EPA algorithm. The contact force is calculated by a Minkowskioverlap based normal model. The rotational motion of polyhedral particles is solved by employing a quaternionbased orientation representation scheme. The energy-conserving nature of the polyhedral DEM method ensures arobust and effective modelling of convex particle systems. The method is applied to simulate the dynamic behaviourof a rockfill system under impact of a high speed projectile. The rockfill sample is generated by a three-dimensionalVoronoi meso method with a specific particle size distribution. The penetrating process of the projectile strikingthe rockfill target is simulated. Some physical quantities associated with the projectile such as the residual velocity,penetration resistance, and deflection angle are monitored which can reflect the influence of the characteristics ofthe rockfill target on its anti-penetration performance. It can be concluded that the developed polyhedral DEMmethod is a very promising numerical approach in analysing the dynamic behaviour of rockfill systems subject tohigh speed projectile impact. 展开更多
关键词 Discrete element method minkowski overlap polyhedral particles rockfill protection system high speed projectile penetration
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Preparation and Flame Retardancy of Polyurethane/POSS Nanocomposites 被引量:3
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作者 薛萌 张献 +3 位作者 吴钊峰 王欢 丁欣 田兴友 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第4期445-450,J0002,共7页
Polyurethane/polyhedral oligomeric sisesquioxane (PU/POSS) nanocomposites were syn- thesized via polymerization utilizing the compatibility between POSS nanopartieles and 4J-diphenyl methylene diisocyanate. Scanning... Polyurethane/polyhedral oligomeric sisesquioxane (PU/POSS) nanocomposites were syn- thesized via polymerization utilizing the compatibility between POSS nanopartieles and 4J-diphenyl methylene diisocyanate. Scanning electron microscope images and Fourier transform infrared spectra revealed that POSS nanoparticles were dispersed in PU matrix. Thermal gravimetric analysis was employed to investigate the thermal decomposition be- havior of PU/POSS nanocomposites at elevated temperatures. Then fire performance was evaluated by limiting oxygen index, underwriters laboratories 94 testing and char residue morphology. These results showed that the addition of POSS promoted the formation of char residues which were covered on the surface of polymer composites, leading to the ira-provement of thermal stability and flame retardancy. 展开更多
关键词 POLYURETHANE polyhedral oligomeric sisesquioxane Flame retardant NANOCOMPOSITE POLYMERIZATION
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Forward Modeling of Gravity,Gravity Gradients,and Magnetic Anomalies due to Complex Bodies 被引量:6
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作者 骆遥 姚长利 《Journal of China University of Geosciences》 SCIE CSCD 2007年第3期280-286,共7页
On the basis of the results of improved analytical expression of computation of gravity anomalies due to a homogeneous polyhedral body composed of polygonal facets, and applying the forward theory with the coordinate ... On the basis of the results of improved analytical expression of computation of gravity anomalies due to a homogeneous polyhedral body composed of polygonal facets, and applying the forward theory with the coordinate transformation of vectors and tensors, we deduced both the analytical expressions for gravity gradient tensors and for magnetic anomalies of a polygon, and obtained new analytical expressions for computing vertical gradients of gravity anomalies and vertical component of magnetic anomalies caused by a polyhedral body. And also we developed explicitly the complete unified expressions for the calculation of gravity anomalies, gravity gradient, and magnetic anomalies due to the homogeneous polyhedron. Furthermore, we deduced new analytical expressions for computing vertical gradients of gravity anomalies due to a finite rectangular prism by applying the newly obtained expressions for gravity gradient tensors due to a polyhedral target body. Comparison with forward calculation of models shows the correctness of these new expressions. It will reduce forward calculation time of gravity-magnetic anomalies and improve computational efficiency by applying our unified expressions for joint forward modeling of gravity-magnetic anomalies due to homogeneous polyhedral bodies. 展开更多
关键词 polyhedral body gravitational field and magnetic field gravity gradient tensor forward calculation coordinate transformation
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Solidification structure of eutectic Al-Si alloy under a high magnetic field-aid-electromagnetic vibration 被引量:4
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作者 Jianbo YU Zhongming REN Weili REN Kang DENG Yunbo ZHONG 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2009年第3期191-196,共6页
An electromagnetic vibration was generated by simultaneously imposing a strong static magnetic field (up to 10 T) and an alternative electricity current to the metal. Its effects on the solidification structure of e... An electromagnetic vibration was generated by simultaneously imposing a strong static magnetic field (up to 10 T) and an alternative electricity current to the metal. Its effects on the solidification structure of eutectic Al-Si alloy have been investigated experimentally. It is found that the eutectic structure has been refined by solely imposing high magnetic field while it is coarsened under the electromagnetic vibration. Furthermore, polyhedral Si grains and non-dendritic α-Al appeared when the electromagnetic vibration strength was strong enough. The refining of eutectic structure is attributed to the decrease of diffusion coefficient caused by the strong magnetic field. The coarseness of eutectic structure may be attributed to the convection caused by electromagnetic vibration. Strong convection may break co-operative growth of eutectic phases to form polyhedral Si grains and non-dendritic α-Al. 展开更多
关键词 Strong magnetic field Electromagnetic vibration Eutectic solidification polyhedral Si Al-Si alloy
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Ultrasmall Nanoparticle ROS Scavengers Based on Polyhedral Oligomeric Silsesquioxanes 被引量:3
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作者 Zhan Li Haotian Li +3 位作者 Jianhua Zhang Xianhu Liu Zhipeng Gu Yiwen Li 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2020年第11期1149-1156,I0004,共9页
Although tremendous efforts have been devoted to the structural and functional tailoring of natural polyphenol-functionalized nan oparticles,preparing ultrasmall sized(<6 nm)particles with precisely-defined structu... Although tremendous efforts have been devoted to the structural and functional tailoring of natural polyphenol-functionalized nan oparticles,preparing ultrasmall sized(<6 nm)particles with precisely-defined structures has remained a grand challenge.In this work,we reported the preparation of ultra-small and precisely structured polyhedral oligomeric silsesquioxanes(POSS)-based polyphenol nanopartides(T8^-,T10^-,and T12^-GAPOSS)by accurately functionalizing the POSS surface with plant polyphenol gallic acid units via thiol-Michael"click"reactions.Those polyphenol nanoparticles exhibited strong free radical scavenging capacity,good biocompatibility and ability to resist cell oxidative damage,which dem on strated great potentials in inhibiting oxidative stress in duced pathologies. 展开更多
关键词 polyhedral oligomeric silsesquioxanes(POSS) POLYPHENOL Ultrasmall nanoparticles Free radical scavenging
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ON ALTERNATIVE OPTIMAL SOLUTIONS TO QUASIMONOTONIC PROGRAMMING WITH LINEAR CONSTRAINTS 被引量:3
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作者 Xue Shengjia 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2007年第1期119-125,共7页
In this paper, the nonlinear programming problem with quasimonotonic ( both quasiconvex and quasiconcave )objective function and linear constraints is considered. With the decomposition theorem of polyhedral sets, t... In this paper, the nonlinear programming problem with quasimonotonic ( both quasiconvex and quasiconcave )objective function and linear constraints is considered. With the decomposition theorem of polyhedral sets, the structure of optimal solution set for the programming problem is depicted. Based on a simplified version of the convex simplex method, the uniqueness condition of optimal solution and the computational procedures to determine all optimal solutions are given, if the uniqueness condition is not satisfied. An illustrative example is also presented. 展开更多
关键词 quasimonotonic programming problem polyhedral set decomposition theorem alternative optimal solution convex simplex method
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Synthesis and Characterization of Ferrocenyl Substituted Styryl Octasilsesquioxane 被引量:2
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作者 Xiao Yan SONG Hai Ping GENG Qi Fang LI 《Chinese Chemical Letters》 SCIE CAS CSCD 2006年第4期427-430,共4页
4-(2-Ferrocenylethenyl)-phenyl-POSS Fc-CH=CH-C6H6-(C5H9)7Si8O12 (FEPS, Fc: ferrocene), containing metal and C=C double bond, was firstly synthesized as a mixture of E/Z isomers by the Wittig reaction. The chemi... 4-(2-Ferrocenylethenyl)-phenyl-POSS Fc-CH=CH-C6H6-(C5H9)7Si8O12 (FEPS, Fc: ferrocene), containing metal and C=C double bond, was firstly synthesized as a mixture of E/Z isomers by the Wittig reaction. The chemical structure of FEPS was characterized by FTIR, ^1H-, ^13C and ^29Si- NMR. 展开更多
关键词 polyhedral silsesquioxane FERROCENE Wittig reaction synthesis.
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