Based on the strong magnetic anisotropy along the symmetry of the crystal, we construct a U(2) non-Abelian gauge potential for the molecular nanomagnet Mn12 by varying the external magnetic field adiabatically. More...Based on the strong magnetic anisotropy along the symmetry of the crystal, we construct a U(2) non-Abelian gauge potential for the molecular nanomagnet Mn12 by varying the external magnetic field adiabatically. Moreover, the non-Abelian geometric phase and the unitary matrix operation, which are tile key steps to realize the universal holonomic quantum computing in the degenerate subspace, are also obtained by means of choosing an evolution path properly.展开更多
N-(2-hydroxy-l-naphthaldene)-4-aminoantipyrine has been synthesized. The structure is determined by X-ray diffraction method and elemental analysis. The crystal system belongs to orthorhombic space group P(2)2(1...N-(2-hydroxy-l-naphthaldene)-4-aminoantipyrine has been synthesized. The structure is determined by X-ray diffraction method and elemental analysis. The crystal system belongs to orthorhombic space group P(2)2(1)2(1). The geometry has been ob- tained from the density functional theory (DFT) method and the B3LYP method employing the 6-31G^* basis sets. The calculated results propose that the latter is close to the experimental data. The structural parameters from the theory are close to those of the crystal and the calculated total energy of coordination is -31677.172 eV. The energy of HOMO and LUMO and the energy gap are 5.179 eV, -1.603 eV and 3.577 eV, respectively.展开更多
Far from being equivalent to host the process, the vessels play an active role in the crystallization thanks to their differently shaped bottoms. It was clearly pointed out through a meticulous experimental research o...Far from being equivalent to host the process, the vessels play an active role in the crystallization thanks to their differently shaped bottoms. It was clearly pointed out through a meticulous experimental research on the batch crystallization of CAM (citric acid monohydrate) carried out in the years 1997-1998 by the author at the historic laboratories of"La Sapienza" University of Rome. Such pioneering M.Sc. thesis, supervised by Prof. Barbara Mazzarotta (Department of Chemical Engineering), was already summarized in an informative essay but, since the crystallization operating conditions to optimize were illustrated "collectively", it seemed necessary a further paper expounding uniquely the geometry effect. Our aim is to use all the data, collected and simulated, in order to show why the round-bottomed crystallizer performed better than the conical-bottomed one with the CAM from aqueous solutions, and why we should discard the flat-bottomed crystallizers.展开更多
The director in nematic liquid crystal cell with a weak anchoring grating substrate and a strong anchoring planar substrate is relative to the coordinates x and z.The influence of the surface geometry of the grating s...The director in nematic liquid crystal cell with a weak anchoring grating substrate and a strong anchoring planar substrate is relative to the coordinates x and z.The influence of the surface geometry of the grating substrate in the cell on the director profile is numerically simulated using the two-dimensional finite-difference iterative method under the condition of one elastic constant approximation and zero driven voltage.The deepness of groove and the cell gap affect the distribution of director.For the relatively shallow groove and the relatively thick cell gap,the director is only dependent on the coordinate z.For the relatively deep groove and the relatively thin cell gap,the director must be dependent on the two coordinates x and z because of the increased elastic strain energy induced by the grating surface.展开更多
The geometrical matching/mismatching of lattices overlapped in 1, 2 and 3 dimensions have been analyzed systematically by variation of lattice misfit in a large range, far beyond the limits for semicoherent interfaces...The geometrical matching/mismatching of lattices overlapped in 1, 2 and 3 dimensions have been analyzed systematically by variation of lattice misfit in a large range, far beyond the limits for semicoherent interfaces. In order to evaluate the degree of matching, the density of good matching site (GMS) between two lattices is calculated. The analysis shows that the GMS density remains approximately constant, irrespectively to the degree of lattice misfit. This constant, defined as the average GMS density, decreases exponentially with the increasing dimension of misfit. Typically, for 6 = 15%, the average GMS densities are approximately 30%, 7%, and 1.4% for 1D, 2D, and 3D lattice misfits, respectively. The GMS density deviates significantly if a CSL of small X can be defined. The relationship between the GMS distribution and O-lattice is investigated. It indicates that an abrupt increase in the GMS density in an interface parallel to a principal O-lattice plane is equivalent to a reduction of dimension of misfit. This shows the agreement between the selections of principal O-lattice planes as candidates of the preferred interfaces and the condition that interfaces with high GMS density are preferred.展开更多
We demonstrate a new kind of multi-core photonic liquid crystal fibers (PLCFs) which have six liquid crystal cores arrayed in the ring-type geometry and separated by the air holes. Through analyzing the structure of t...We demonstrate a new kind of multi-core photonic liquid crystal fibers (PLCFs) which have six liquid crystal cores arrayed in the ring-type geometry and separated by the air holes. Through analyzing the structure of this kind of PLCFs, it can be found that they have the ability to resist the structure deformation. Due to the effective index of the liquid crystal can be adjusted by temperature and wavelength, the energy in the six liquid crystal cores is increased with the temperature increasing and wavelength decreasing. The effective index of the PLCFs is decreased, the effective fundamental mode area is increased and the dispersion properties are gently affected with the wavelength increasing and temperature decreasing.展开更多
Understanding the evolution process and formation mechanism of nanoscale structures is crucial to controllable synthesis of inorganic nanomaterials with well-defined geometries and unique functionalities. In addition ...Understanding the evolution process and formation mechanism of nanoscale structures is crucial to controllable synthesis of inorganic nanomaterials with well-defined geometries and unique functionalities. In addition to the conventional Ostwald ripening process, oriented aggregation has been recently found to be prevalent in nanocrystal growth. In this new mechanism, primary small nanocrystals firstly spontaneously aggregate in the manner of oriented attachment, and then the large crystalline materials are formed via the process of interparticle recrystallization. Furthermore, controllable fabrication of the ordered nanocrystal solid materials that has shown specific collective properties will promote the application of inorganic nanocrystal in devices. Therefore, investigation of the mechanism of oriented aggregation is essential to controllable synthesis of nanocrystals and ordered nanocrystal solid materials. In this review, we summarize recent advances in the preparation of nanocrystal materials, which are mostly focused on our work about the role of self-assembly in construction of inorganic nanostructural materials.展开更多
A stretch-release strategy is proposed to analyze the problem of surface energy-induced stress fields in nanocrystals,which is resolved into a stretch sub-problem and a release sub-problem using the superposition prin...A stretch-release strategy is proposed to analyze the problem of surface energy-induced stress fields in nanocrystals,which is resolved into a stretch sub-problem and a release sub-problem using the superposition principle.The surface effect of silicon nanowires with hexagonal cross-sections is analyzed by the proposed method.The severe stress concentration near the triple junctions of the wire surfaces and the large shear stress on the plane{111}is quantified,which provides a solid mechanical explanation for the kink phenomena in growth transition from direction〈111〉to〈112〉observed in experiments.Different from the conventional view of negligible surface effect for bulk material,we found that there exists a size-independent part of the surface effect on the stress in the order of tens or hundreds of mega Pascal,which corresponds to the stretch-induced biaxial stress in the surface layer and the shape influence of the geometry of nanocrystals.This size-independent part could well explain the size-independent kinking phenomenon during the growth of silicon nanowires.展开更多
According to the Ringel-Green theorem,the generic composition algebra of the Hall algebra provides a realization of the positive part of the quantum group.Furthermore,its Drinfeld double can be identified with the who...According to the Ringel-Green theorem,the generic composition algebra of the Hall algebra provides a realization of the positive part of the quantum group.Furthermore,its Drinfeld double can be identified with the whole quantum group,in which the BGP-reflection functors coincide with Lusztig's symmetries.It is first asserted that the elements corresponding to exceptional modules lie in the integral generic composition algebra,hence in the integral form of the quantum group.Then it is proved that these elements lie in the crystal basis up to a sign.Eventually,it is shown that the sign can be removed by the geometric method.The results hold for any type of Cartan datum.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos. 11074154, 11074184, and 11075099the National Science Funding of Zhejiang Province under Grant No. Y6090001
文摘Based on the strong magnetic anisotropy along the symmetry of the crystal, we construct a U(2) non-Abelian gauge potential for the molecular nanomagnet Mn12 by varying the external magnetic field adiabatically. Moreover, the non-Abelian geometric phase and the unitary matrix operation, which are tile key steps to realize the universal holonomic quantum computing in the degenerate subspace, are also obtained by means of choosing an evolution path properly.
文摘N-(2-hydroxy-l-naphthaldene)-4-aminoantipyrine has been synthesized. The structure is determined by X-ray diffraction method and elemental analysis. The crystal system belongs to orthorhombic space group P(2)2(1)2(1). The geometry has been ob- tained from the density functional theory (DFT) method and the B3LYP method employing the 6-31G^* basis sets. The calculated results propose that the latter is close to the experimental data. The structural parameters from the theory are close to those of the crystal and the calculated total energy of coordination is -31677.172 eV. The energy of HOMO and LUMO and the energy gap are 5.179 eV, -1.603 eV and 3.577 eV, respectively.
文摘Far from being equivalent to host the process, the vessels play an active role in the crystallization thanks to their differently shaped bottoms. It was clearly pointed out through a meticulous experimental research on the batch crystallization of CAM (citric acid monohydrate) carried out in the years 1997-1998 by the author at the historic laboratories of"La Sapienza" University of Rome. Such pioneering M.Sc. thesis, supervised by Prof. Barbara Mazzarotta (Department of Chemical Engineering), was already summarized in an informative essay but, since the crystallization operating conditions to optimize were illustrated "collectively", it seemed necessary a further paper expounding uniquely the geometry effect. Our aim is to use all the data, collected and simulated, in order to show why the round-bottomed crystallizer performed better than the conical-bottomed one with the CAM from aqueous solutions, and why we should discard the flat-bottomed crystallizers.
基金Supported by Natural Science Foundation of Hebei Province under Grant No.A2010000004the National Natural Science Foundation of China under Grant Nos.10704022 and 60736042the Key Subject Construction Project of Hebei Province University
文摘The director in nematic liquid crystal cell with a weak anchoring grating substrate and a strong anchoring planar substrate is relative to the coordinates x and z.The influence of the surface geometry of the grating substrate in the cell on the director profile is numerically simulated using the two-dimensional finite-difference iterative method under the condition of one elastic constant approximation and zero driven voltage.The deepness of groove and the cell gap affect the distribution of director.For the relatively shallow groove and the relatively thick cell gap,the director is only dependent on the coordinate z.For the relatively deep groove and the relatively thin cell gap,the director must be dependent on the two coordinates x and z because of the increased elastic strain energy induced by the grating surface.
基金supported from the National Natural Science Foundation of China (Grant No. 1171088)the National Basic Research Program of China (Grant No. 12CB619403) from Chinese Ministry of Science and Technology
文摘The geometrical matching/mismatching of lattices overlapped in 1, 2 and 3 dimensions have been analyzed systematically by variation of lattice misfit in a large range, far beyond the limits for semicoherent interfaces. In order to evaluate the degree of matching, the density of good matching site (GMS) between two lattices is calculated. The analysis shows that the GMS density remains approximately constant, irrespectively to the degree of lattice misfit. This constant, defined as the average GMS density, decreases exponentially with the increasing dimension of misfit. Typically, for 6 = 15%, the average GMS densities are approximately 30%, 7%, and 1.4% for 1D, 2D, and 3D lattice misfits, respectively. The GMS density deviates significantly if a CSL of small X can be defined. The relationship between the GMS distribution and O-lattice is investigated. It indicates that an abrupt increase in the GMS density in an interface parallel to a principal O-lattice plane is equivalent to a reduction of dimension of misfit. This shows the agreement between the selections of principal O-lattice planes as candidates of the preferred interfaces and the condition that interfaces with high GMS density are preferred.
基金supported by the National Natural Science Foundation of China (Nos.61077047 and 61107059)the Natural Science Foundation of Heilongjiang Province (No.A200914)the Research Fund for the Doctoral Program of Higher Education of China (No.200802171034)
文摘We demonstrate a new kind of multi-core photonic liquid crystal fibers (PLCFs) which have six liquid crystal cores arrayed in the ring-type geometry and separated by the air holes. Through analyzing the structure of this kind of PLCFs, it can be found that they have the ability to resist the structure deformation. Due to the effective index of the liquid crystal can be adjusted by temperature and wavelength, the energy in the six liquid crystal cores is increased with the temperature increasing and wavelength decreasing. The effective index of the PLCFs is decreased, the effective fundamental mode area is increased and the dispersion properties are gently affected with the wavelength increasing and temperature decreasing.
基金supported by the National Natural Science Foundation for Distinguished Youth Scholars of China (21025310, Z.Y.T.)National Natural Science Foundation of China (91027011, Z.Y.T.)National Basic Research Program of China (973 Program) (2009CB930401,Z.Y.T.)
文摘Understanding the evolution process and formation mechanism of nanoscale structures is crucial to controllable synthesis of inorganic nanomaterials with well-defined geometries and unique functionalities. In addition to the conventional Ostwald ripening process, oriented aggregation has been recently found to be prevalent in nanocrystal growth. In this new mechanism, primary small nanocrystals firstly spontaneously aggregate in the manner of oriented attachment, and then the large crystalline materials are formed via the process of interparticle recrystallization. Furthermore, controllable fabrication of the ordered nanocrystal solid materials that has shown specific collective properties will promote the application of inorganic nanocrystal in devices. Therefore, investigation of the mechanism of oriented aggregation is essential to controllable synthesis of nanocrystals and ordered nanocrystal solid materials. In this review, we summarize recent advances in the preparation of nanocrystal materials, which are mostly focused on our work about the role of self-assembly in construction of inorganic nanostructural materials.
基金the National Natural Science Foundation of China(Grant No.11872237)the Natural Science Foundation of Shanghai(Grant No.18ZR1414600)the Challenging Project from China Academy of Engineering Physics.
文摘A stretch-release strategy is proposed to analyze the problem of surface energy-induced stress fields in nanocrystals,which is resolved into a stretch sub-problem and a release sub-problem using the superposition principle.The surface effect of silicon nanowires with hexagonal cross-sections is analyzed by the proposed method.The severe stress concentration near the triple junctions of the wire surfaces and the large shear stress on the plane{111}is quantified,which provides a solid mechanical explanation for the kink phenomena in growth transition from direction〈111〉to〈112〉observed in experiments.Different from the conventional view of negligible surface effect for bulk material,we found that there exists a size-independent part of the surface effect on the stress in the order of tens or hundreds of mega Pascal,which corresponds to the stretch-induced biaxial stress in the surface layer and the shape influence of the geometry of nanocrystals.This size-independent part could well explain the size-independent kinking phenomenon during the growth of silicon nanowires.
基金supported by the National Natural Science Foundation of China (No. 10631010) the NationalKey Basic Research Programme of China (No. 2006CB805905)
文摘According to the Ringel-Green theorem,the generic composition algebra of the Hall algebra provides a realization of the positive part of the quantum group.Furthermore,its Drinfeld double can be identified with the whole quantum group,in which the BGP-reflection functors coincide with Lusztig's symmetries.It is first asserted that the elements corresponding to exceptional modules lie in the integral generic composition algebra,hence in the integral form of the quantum group.Then it is proved that these elements lie in the crystal basis up to a sign.Eventually,it is shown that the sign can be removed by the geometric method.The results hold for any type of Cartan datum.