Three-dimensional Lattice Structure Research Articles

Stochastic growth dynamics and composite defects in quenched immiscible binary condensates

We study the topological configurations of the two-component condensates of bosons with the $3$D $\vec{\sigma}\cdot \vec{p}$ Weyl-type spin-orbit coupling subject to a harmonic trapping potential. The topology of the condensate wavefunctions manifests in the quaternionic representation. In comparison to the $U(1)$ complex phase, the quaternionic phase manifold is $S^3$ and the spin orientations form the $S^2$ Bloch sphere through the 1st Hopf mapping. The spatial distributions of the quaternionic phases exhibit the 3D skyrmion configurations, and the spin distributions possess non-trivial Hopf invariants. Spin textures evolve from the concentric distributions at the weak spin-orbit coupling regime to the rotation symmetry breaking patterns at the intermediate spin-orbit coupling regime. In the strong spin-orbit coupling regime, the single-particle spectra exhibit the Landau-level type quantization. In this regime, the three-dimensional skyrmion lattice structures are formed when interactions are below the energy scale of Landau level mixings. Sufficiently strong interactions can change condensates into spin-polarized plane-wave states, or, superpositions of two plane-waves exhibiting helical spin spirals.

Synthesis of Polymetallic Oxides with High Organized Structure

Abstract The synthesis and characterization of high organized and nanostructured polymetallic oxides were studied. The samples were synthesized by sol-gel autocombustion method, using glycine as chelating/fuel agent and polyacrylamide-based hydrogel as template agent. This polymer has a porous microstructure with well-individualized and regularly-dispersed pores. The asobtained samples were characterized by IR spectroscopy, XRD, SEM. The magnetic properties were studied. As-synthesized polymetallic oxides have the morphological structure given by the three-dimensional lattice structure of hydrogel used as template agent

Enhancing Optical Up-Conversion Through Electrodynamic Coupling with Ancillary Chromophores

In lanthanide-based optical materials, control over the relevant operating characteristics–for example transmission wavelength, phase and quantum efficiency–is generally achieved through the modification of parameters such as dopant/host combination, chromophore concentration and lattice structure. An alternative avenue for the control of optical response is through the introduction of secondary, codoped chromophores. Here, such secondary centers act as mediators, commonly bridging the transfer of energy between primary absorbers of externally sourced optical input and other sites of frequency-converted emission. Utilizing theoretical models based on experimentally feasible, three-dimensional crystal lattice structures; a fully quantized theoretical framework provides insights into the locally modified mechanisms that can be implemented within such systems. This leads to a discussion of how such effects might be deployed to either enhance, or potentially diminish, the efficiency of frequency up-conversion.

Quantum spin liquid with a Majorana Fermi surface on the three-dimensional hyperoctagon lattice

Motivated by the recent synthesis of $\ensuremath{\beta}$-Li${}_{2}$IrO${}_{3}$---a spin-orbit entangled $j=1/2$ Mott insulator with a three-dimensional lattice structure of the Ir${}^{4+}$ ions---we consider generalizations of the Kitaev model believed to capture some of the microscopic interactions between the iridium moments on various trivalent lattice structures in three spatial dimensions. Of particular interest is the so-called hyperoctagon lattice---the premedial lattice of the hyperkagome lattice, for which the ground state is a gapless quantum spin liquid where the gapless Majorana modes form an extended two-dimensional Majorana Fermi surface. We demonstrate that this Majorana Fermi surface is inherently protected by lattice symmetries and discuss possible instabilities. We thus provide the first example of an analytically tractable microscopic model of interacting SU(2) spin-$\frac{1}{2}$ degrees of freedom in three spatial dimensions that harbors a spin liquid with a two-dimensional spinon Fermi surface.

Di-μ-acetato-κ4O:O′-bis[(1,10-phenanthroline-κ2N,N′)(trifluoromethanesulfonato-κO)copper(II)

The complete molecule of the title compound, [Cu2(C2H3O2)2(CF3O3S)2(C12H8N2)2], is completed by the application of a twofold rotation and comprises two CuII ions, each of which is penta­coordinated by two N atoms from a bidentate 1,10-phenanthroline (phen) ligand, two O atoms from acetate ligands and an O atom from a tri­fluoro­methane­sulfonate anion, forming a (4 + 1) distorted square-pyramidal coordination geometry. The CuII ions are connected by two acetate bridges in a syn–syn configuration. The F atoms of the tri­fluoro­methane­sulfonate ligands are disordered, with site-occupation factors of 70 and 30. The molecular structure is stabilized by intra­molecular face-to-face π–π inter­actions with centroid–centroid distances in the range 3.5654 (12)–3.8775(12) Å. The crystal structure is stabilized by C—H⋯O interactions, leading to a three-dimensional lattice structure.

Three-dimensional Composite Lattice Structures Fabricated by Electrical Discharge Machining

We present a novel method for fabricating carbon fiber composite sandwich panels with lattice core construction by means of electrical discharge machining (EDM). First, flat-top corrugated carbon fiber composite cores were fabricated by a hot press molding method. Then, two composite face sheets were bonded to each corrugated core to create precursor sandwich panels. These panels were transformed into sandwich panels with near-pyramidal truss cores by EDM plunge-cutting the corrugated core between the face sheets with a shaped cuprite electrode. The flat top corrugation permits adhesive to be applied consistently, and the selected dimensions leave a substantial bond area after cutting, resulting in a strong core-to-sheet bond. The crushing behavior of this novel construction was investigated in flatwise compression, and the results were compared to analytical expressions for strength and stiffness.

Optical induction of 3D rotational symmetry refractive lattices by combined interferometric-mask method in doped LiNbO3 crystals

A novel combined interferometric–mask method for the formation of micro- and nanometric scale three-dimensional (3D) rotational symmetry quasi-crystalline refractive lattice structures in photorefractive materials is demonstrated experimentally. The method is based on micrometric scale spatial modulation of the light by amplitude mask in the radial directions and along the azimuthal angle and the use of counter-propagating beam geometry building up Gaussian standing wave, which defines the light modulation in the axial direction with half-wavelength periodicity. 3D intensity pattern can be represented as numerous mask-generated 2D quasi-periodic structures located in each anti-node of the standing wave. The formed 3D intensity distributions of the optical beams can be imparted into the photorefractive medium thus creating the micro- and sub-micrometric scale 3D refractive index volume lattices. The used optical scheme allows also the formation of 2D lattices by removing the back-reflecting mirror. 2D and 3D refractive lattices were recorded with the use of 532 nm laser beam and rotational symmetry mask in doped lithium niobate crystals and were tested by the probe beam far-field diffraction pattern imaging and direct observation by phase microscope. The formed rotational symmetry 3D refractive structures have the periods of 20–60 μm in the radial directions, 60 μm along the azimuthal angle and half-wavelength 266 nm in the axial direction.

A novel slow-release urea fertiliser: Physical and chemical analysis of its structure and study of its release mechanism

Reducing the release rate of urea can increase its efficiency of use and reduce nitrogen pollution. A slow-release urea (S-urea) was produced using a new method; a bentonite and organic polymer (OP) were used to form a three-dimensional lattice structure by melting urea directly. The structure affected the recrystallisation of urea and increased its stacking density. The specific surface area of S-urea was 0.046 m2 g−1, much lower than that of common urea (1.698 m2 g−1). The static release experiment showed that 75% of 12 g sample of S-urea was released in 1 l water for about 14 h, much longer than that of common urea (<0.5 h). The kinetic simulation results showed that the release of S-urea was not based on Fickian diffusion but underwent anomalous diffusion with its release rate was mainly affected by the dissolving-eroding process of the medium which was controlled by the compactness of the lattice structure. This process may be strengthened by increasing the amount of bentonite.

Unusually stable ~100-fold reversible and instantaneous swelling of inorganic layered materials

Cells can swell or shrink in certain solutions; however, no equivalent activity has been observed in inorganic materials. Although lamellar materials exhibit increased volume with increase in the lamellar period, the interlamellar expansion is usually limited to a few nanometres, with a simultaneous partial or complete exfoliation into individual atomic layers. Here we demonstrate a large monolithic crystalline swelling of layered materials. The gallery spacing can be instantly increased ~100-fold in one direction to ~90 nm, with the neighbouring layers separated primarily by H2O. The layers remain strongly held without peeling or translational shifts, maintaining a nearly perfect three-dimensional lattice structure of >3,000 layers. First-principle calculations yield a long-range directional structuring of the H2O molecules that may help to stabilize the highly swollen structure. The crystals can also instantaneously shrink back to their original sizes. These findings provide a benchmark for understanding the exfoliating layered materials.

Effect of Antibodies to Myosin Head Reveals Definite Difference between In Vitro Actin-Myosin Sliding and Muscle Contraction

Mechanism of myosin head power stroke, responsible for muscle contraction, still remains to be a matter of debate and speculation. Despite considerable progress in studying actin filament sliding over myosin fixed on a glass surface, it is not clear whether the in vitro actin-myosin sliding takes place by a mechanism similar to contraction in muscle, consisting of three-dimensional myofilament lattice structures. To make this point clear, we prepared two different monoclonal antibodies, one directed to reactive lysine residue close to the myosin head converter region (anti-RLR antibody) while the other directed to two peptides of regulatory light chain in the myosin head lever arm region (anti-LD antibody). We compared the effect of these antibodies on in vitro actin- myosin sliding and contraction of skinned rabbit psoas muscle fibers with the following results: (1) anti-RLR antibody completely inhibited in vitro actin-myosin sliding without changing actin-activated myosin head ATPase activity, while it showed no effect on Ca2+-activated contraction of muscle fibers; (2) anti-LD antibody had no effect on in vitro actin-myosin sliding, but suppressed Ca2+-activated muscle fiber contraction without changing Mg-ATPase activity. These results indicate definite difference between in vitro actin-myosin sliding and muscle contraction.

Interaction of cell culture with composition effects on the mechanical properties of polycaprolactone-hydroxyapatite scaffolds fabricated via selective laser sintering (SLS)

In the current study PCL/HA composites were fabricated using SLS as two- and three-dimensional lattice structures and exposed to a cellular component (MC 3T3 osteoblast-like cells). The main aims were to determine the mechanical differences due to powder composition and to observe the physical and mechanical changes pertaining to cell presence. These structures were characterized by compressive mechanical testing, and the effects of cell culturing and degradation on mechanical properties of the scaffolds with different PCL/HA compositions were determined. Moreover, changes in the scaffold morphology due to the cell culture conditions were determined by μ-CT analysis.Cells steadily grew on the scaffolds for 21days with preferential distribution around the macropores and initially PCL/HA(15%) composites had higher cell numbers. Removal of loosely sintered parts was observable during the culturing period. Cell culture conditions did not change the compressive moduli significantly but had a distinct effect on compressive strength. For PCL/HA(15%) composites, an initial loss in strength caused by cell culture was reversed by longer cell exposure, with compressive strength of the structures restored to the initial properties (p≤0.05). μ-CT measurements showed widespread morphological changes in the scaffolds, such as a decrease in the roughness of the struts. In general, in the initial period composites with lower HA content (15wt.%) showed better metabolic activity compared to the higher HA content, however by day 14 the performance of the two compositions was equal. These results suggest that changes in sintering due to the differences in powder composition can have profound effects on the short and long term mechanical properties of the scaffold particularly under cell culture conditions, and this should be closely considered for SLS processing of scaffolds.

Ethylene glycol-assisted nanocrystallization of LiFePO4 for a rechargeable lithium-ion battery cathode

Hydro- and/or solvo-thermal nanocrystallization of lithium iron phosphate (LiFePO4) has been well recognized as an effective pathway to improve its electrochemical performances. Herein, it is reported that high-performance LiFePO4 single-crystalline nanoparticles have been successfully prepared by the additive-free solvothermal reaction and subsequent glucose-assisted calcination. In comparison with the similar hydrothermal reaction, the presence of ethylene glycol can unexpectedly induce the formation of gel-like intermediates at the time interval of 0.5 h, resulting in LiFePO4 nanoparticles with a three-dimensional (3D) lattice structure and an amorphous nanocoating for a reaction time of 2 h. Interestingly, the lattice structure of growing LiFePO4 crystals can be thoroughly damaged under the irradiation of an electron beam. Furthermore, after the continuous crystal growth and subsequent heat-treatment, nanocrystalline LiFePO4 can achieve a discharge capacity of ∼165 mAh g−1 at 0.1 C in assembled LiFePO4/Li half-cells, proving a successful nanocrystal-forming engineering of LiFePO4 for a lithium-ion battery cathode.

Reconfigurable 3D photonic lattices by optical induction for optical control of beam propagation

We report on our recent theoretical and experimental studies of three-dimensional (3D) photonic lattice structures which are established in a bulk nonlinear crystal by employing different optical induction techniques. These 3D photonic lattices bring about new opportunities for controlling the flow of light via coupling engineering originated from the lattice modulation along the beam propagation direction. By fine tuning the lattice parameters, we observe a host of unusual behaviors of beam propagation in such reconfigurable 3D lattices, including enhanced discrete diffraction, light tunneling inhibition—better known as coherent destruction of tunneling (CDT), anomalous diffraction, negative refraction, as well as CDT-based image transmission. In addition, we propose and demonstrate a new way of creating 3D ionic-type photonic lattices by controlled Talbot effect.

Zero-temperature phases for chiral magnets in three dimensions

We calculate the energies of various multiple-spiral spin configurations for the three-dimensional model of chiral magnets. The ground-state phase diagram is obtained in the space of anisotropy, magnetic field, and interaction parameters. Regimes with multiple-spiral, or spin crystal ground states of two- and three-dimensional nature are identified. The Skyrmion number responsible for anomalous Hall effect is examined for each spin crystal configuration. A geometric interpretation is given for the three-dimensional spin crystal lattice structures as the periodic arrangement of hedgehog and anti-hedgehog singularities.

Model updating of lattice structures: A substructure energy approach

Model updating is an inverse problem to identify and correct uncertain modeling parameters, which leads to better predictions of the dynamic behavior of a target structure. This study presents a direct physical property adjustment method and the substructure energy approach, which can accurately update the stiffness and mass matrices of lattice structures using incomplete eigenvectors measured from critical substructures. For validation, the proposed method is applied to update models of a mass-spring system, a two-dimensional, and a three-dimensional lattice structure.

Shear Deformation Response for Three-Dimensional Lattice Structures(2nd Report, Effects of Unit Cell Geometry in a Lattice Structure)

In this paper, the shear response of three-dimensional lattice structure was investigated based on numerical stress analysis, FEM. In particular, effects of number of unit cells in three directions on the mechanical properties (shear modulus G* and collapse strength τ*) of lattice structures were discussed based on theoretical analysis and FEM. It is found that the mechanical properties strongly depend on the number of unit cell in three directions x,y,z, and for a flat structure(Ny=1), the deformation pattern in the structure can be classified into two types. The shear modulus G* for a flat structure obtained by FEM can be estimated by the elementary beam theory with a good accuracy. Also, for a flat structure with slender struts, the collapse is occurred by elastic buckling, and that with relatively thicker struts, the collapse strength agrees well with the theoretical result. Moreover, the cubic structure having the same number of unit cell in x and z directions(Nx=Nz=N) shows a unit curve for the shear modulus G*, so that the modulus can be estimated by the curve for various cubic structures.

Reconfigurable Optically Induced Quasicrystallographic Three‐Dimensional Complex Nonlinear Photonic Lattice Structures

Complex reconfigurable 3D photonic quasicrystals (PQCs) are fabricated in nonlinear photorefractive strontium barium niobate by an optical phase engineering-based single-step optical induction approach (see image). The approach demonstrates the embedded potential to use these structures as a reconfigurable platform for the investigation of advanced nonlinear light-matter interaction, or as templates fabricated in various photosensitive materials for photonic bandgap structures.

3次元ラティス構造のせん断変形特性 : 第1報,ラティス構造全体の幾何形状の影響

3次元ラティス構造のせん断変形特性 : 第1報,ラティス構造全体の幾何形状の影響

Five beam holographic lithography for simultaneous fabrication of three dimensional photonic crystal templates and line defects using phase tunable diffractive optical element

This paper demonstrates an approach for laser holographic patterning of three-dimensional photonic lattice structures using a single diffractive optical element. The diffractive optical element is fabricated by recording gratings in a photosensitive polymer using a two-beam interference method and has four diffraction gratings oriented with four-fold symmetry around a central opening. Four first-order diffracted beams from the gratings and one non-diffracted central beam overlap and form a three-dimensional interference pattern. The phase of one side beam is delayed by inserting a thin piece of microscope glass slide into the beam. By rotating the glass slide, thus tuning the phase of the side beam, the five beam interference pattern changes from face-center tetragonal symmetry into diamond-like lattice symmetry with an optimal bandgap. Three-dimensional photonic crystal templates are produced in a photoresist and show the phase tuning effect for bandgap optimization. Furthermore, by integrating an amplitude mask in the central opening, line defects are produced within the photonic crystal template. This paper presents the first experimental demonstration on the holographic fabrication approach of three-dimensional photonic crystal templates with functional defects by a single laser exposure using a single optical element.

Phase tunable holographic fabrication for three-dimensional photonic crystal templates by using a single optical element

This paper demonstrates a phase tunable holographic fabrication of three-dimensional photonic lattice structures using a single optical element. A top-cut four-side prism is employed to generate five-beam three-dimensional interference patterns. A silica glass slide is inserted into the optical path to adjust the phase of one interfering beam relative to other four beams. The phase control of the interfering laser beam renders the lattice of the interference pattern from a face-center tetragonal symmetry into a high contrast, interconnecting diamondlike symmetry. This method provides a flexible approach to fabricating three-dimensional photonic lattices with improved photonic band structures.