Blade Segment with a 3D Lattice of Diamond Grits Fabricated via an Additive Manufacturing Process

Diamond tools with orderly arrangements of diamond grits have drawn considerable attention in the machining field owing to their outstanding advantages of high sharpness and long service life.This diamond super tool,as well as the manufacturing equipment,has been unavailable to Chinese enterprises for a long time due to patents.In this paper,a diamond blade segment with a 3D lattice of diamond grits was additively manufactured using a new type of cold pressing equipment(AME100).The equipment,designed with a rotary working platform and 16 molding stations,can be used to additively manufacture segments with diamond grits arranged in an orderly fashion,layer by layer;under this additive manufacturing process,at least 216000 pcs of diamond green segments with five orderly arranged grit layers can be produced per month.The microstructure of the segment was observed via SEM and the diamond blade fabricated using these segments was compared to other commercial cutting tools.The experimental results showed that the 3D lattice of diamond grits was formed in the green segment.The filling rate of diamond grits in the lattice could be guaranteed to be above 95%;this is much higher than the 90%filling rate of the automatic array system(ARIX).When used to cut stone,the cutting amount of the blade with segments made by AME100 is two times that of ordinary tools,with the same diamond concentration.When used to dry cut reinforced concrete,its cutting speed is 10%faster than that of ARIX.Under wet cutting conditions,its service life is twice that of ARIX.By applying the machine vision online inspection system and a special needle jig with a negative pressure system,this study developed a piece of additive manufacturing equipment for efficiently fabricating blade segments with a 3D lattice of diamond grits.

Green’s Functions and DOS for Some 2D Lattices

In this presentation we present the Green’s functions and density of states for the most frequently encountered 2D lattices: square, triangular, honeycomb, kagome, and Lieb lattice. Though the results are well known, we hope that its derivation performed in a uniform way provides some pedagogical value.

A Hybrid Lattice Boltzmann Flux Solver for Simulation of Viscous Compressible Flows

In this paper,a hybrid lattice Boltzmann flux solver(LBFS)is proposed for simulation of viscous compressible flows.In the solver,the finite volume method is applied to solve the Navier-Stokes equations.Different from conventional Navier-Stokes solvers,in this work,the inviscid flux across the cell interface is evaluated by local reconstruction of solution using one-dimensional lattice Boltzmann model,while the viscous flux is still approximated by conventional smooth function approximation.The present work overcomes the two major drawbacks of existing LBFS[28–31],which is used for simulation of inviscid flows.The first one is its ability to simulate viscous flows by including evaluation of viscous flux.The second one is its ability to effectively capture both strong shock waves and thin boundary layers through introduction of a switch function for evaluation of inviscid flux,which takes a value close to zero in the boundary layer and one around the strong shock wave.Numerical experiments demonstrate that the present solver can accurately and effectively simulate hypersonic viscous flows.

Quench dynamics of ultracold atoms in one-dimensional optical lattices with artificial gauge fields

We study the quench dynamics of noninteracting ultracold atoms loaded in one-dimensional （1D） optical lattices with artificial gauge fields, which are modeled by lattices with complex hopping coefficients. After suddenly changing the hopping coefficient, time evolutions of the density distribution, momentum distribution, and mass current at the center are studied for both finite uniform systems and trapped systems. Effects of filling factor, system size, statistics, harmonic trap, and phase difference in hopping are identified, and some interesting phenomena show up. For example, for a finite uniform fermionic system shock and rarefaction wave plateaus are formed at two ends, whose wave fronts move linearly with speed equaling to the maximal absolute group velocity. While for a finite uniform bosonic system the whole density distribution moves linearly at the group velocity. Only in a finite uniform fermionic system there can be a constant quasi- steady-state current, whose amplitude is decided by the phase difference and filling factor. The quench dynamics can be tested in ultracold atoms with minimal modifications of available experimental techniques, and it is a very interesting and fundamental example of the transport phenomena and the nonequilibrium dynamics.

The 3D solitons and vortices in 3D discrete monatomic lattices with cubic and quartic nonlinearity

By virtue of the method of multiple-scale and the quasi-discreteness approach, we have discussed the nonlinear vibration equation of a 3D discrete monatomic lattice with its nearest-neighbours interaction. The 3D simple cubic lattices have the same localized modes as a 1D discrete monatomic chain with cubic and quartic nonlinearity. The nonlinear vibration in the 3D simple cubic lattice has 3D distorted solitons and 3D envelop solitons in the direction of kx = ky = kz = k and k = ±π/6α0 in the Brillouin zone, as well as has 3D vortices in the direction of kx = ky = kz = k and k = ±π/α0 in the Brillouin zone.

Transverse Localization of Light in 1D Self-Focusing Parity-Time-Symmetric Optical Lattices

Transverse localization of light is investigated numerically in a serf-focusing Kerr medium with a complex-valued optical lattice featuring parity-time symmetry. It is demonstrated that the light localization exists below the threshold of the spatial frequency of the lattices, and is further enhanced with the decrease of the spatial frequency. The influence of defects on the transverse localization is also discussed in detail. The results show that both positive and negative defects in such a medium would enhance the localization.

Glial scar size, inhibitor concentration, and growth of regenerating axons after spinal cord transection

A mathematical model has been formulated in accordance with cell chemotaxis and relevant experimental data. A three-dimensional lattice Boltzmann method was used for numerical simulation. The present study observed the effects of glial scar size and inhibitor concentration on regenerative axonal growth following spinal cord transection. The simulation test comprised two parts： （1） when release rates of growth inhibitor and promoter were constant, the effects of glial scar size on axonal growth rate were analyzed, and concentrations of inhibitor and promoters located at the moving growth cones were recorded. （2） When the glial scar size was constant, the effects of inhibitor and promoter release rates on axonal growth rate were analyzed, and inhibitor and promoter concentrations at the moving growth cones were recorded. Results demonstrated that （1） a larger glial scar and a higher release rate of inhibitor resulted in a reduced axonal growth rate. （2） The axonal growth rate depended on the ratio of inhibitor to promoter concentrations at the growth cones. When the average ratio was 〈 1.5, regenerating axons were able to grow and successfully contact target cells.

Perforation optimization of layer-penetration fracturing for commingling gas production in coal measure strata

Optimization of fracturing perforation is of great importance to the commingling gas production in coal measure strata.In this paper,a 3 D lattice algorithm hydraulic fracturing simulator was employed to study the effects of perforation position and length on hydraulic fracture propagation in coal measures of the Lin-Xing block,China.Based on field data,three lithologic combinations are simulated:1)a thick section of coal seam sandwiched by sandstones;2)a thin coal seam layer overlay by gas-bearing tight sandstone;3)two coal seams separated by a thin layer of sandstone.Our simulation shows that perforation position and length in multi-layer reservoirs play a major role in hydraulic fracture propagation.Achieving maximum stimulated volume requires consideration of lithologic sequence,coal seam thickness,stress states,and rock properties.To improve the combined gas production in coal measure strata,it is possible to simultaneously stimulate multiple coal seams or adjacent gas-bearing sandstones.In these cases,perforation location and length also significantly impact fracture propagation,and therefore should be carefully designed.Our simulation results using 3 D lattice algorithm are qualitatively consistent with laboratory physical simulation.3 D lattice models can be used to effectively simulate the fracture propagation through layers in coal measure strata.The numerical results provide guidance for perforation optimization in the hydraulic fracturing of coal measure strata.

Temperature dependence of heat conduction coefficient in nanotube/nanowire networks

Studies on heat conduction are so far mainly focused on regular systems such as the one-dimensional（1D） and twodimensional（2D） lattices where atoms are regularly connected and temperatures of atoms are homogeneously distributed.However, realistic systems such as the nanotube/nanowire networks are not regular but heterogeneously structured, and their heat conduction remains largely unknown. We present a model of quasi-physical networks to study heat conduction in such physical networks and focus on how the network structure influences the heat conduction coefficient κ. In this model,we for the first time consider each link as a 1D chain of atoms instead of a spring in the previous studies. We find that κ is different from link to link in the network, in contrast to the same constant in a regular 1D or 2D lattice. Moreover, for each specific link, we present a formula to show how κ depends on both its link length and the temperatures on its two ends.These findings show that the heat conduction in physical networks is not a straightforward extension of 1D and 2D lattices but seriously influenced by the network structure.

Self-trapping and oscillation of quadruple beams in high band gap of 2D photonic lattices

through single-site excitation. By changing the initial to the lattices, periodic oscillations of the localized quadruple state becomes a rotating doubly charged undergo charge-flipping when the rotating direction is orientation of the incident quadruple beam related quadruple mode may be obtained. The localized optical vortex （DCV） during rotation and should reversed.

Ferromagnetic coupling in a two-dimensional Cairo pentagonal Ni_(2)(TCNQ)_(2) lattice

Magnetism has revolutionized important technologies,and continues to bring forth new phenomena in emergent materials and reduced dimensions.Here,using first-principles calculations,we demonstrate that the already-synthesized two-dimensional(2D)Ni-tetracyanoquinodimethane(Ni_(2)(TCNQ)_(2))lattice is a stable ferromagnetism material with multiple spin-polarized Dirac cones.The conical bands in proximity of the Fermi level can be tuned by external tensile strain and show the fourfold degenerate electronic states at the critical tensile strain of~2.35%,whose energy dispersion is consistent with 2D Cairo pentagonal lattice.In addition,spin-orbital coupling can open a band gap at the Dirac point of A,leading to topologically nontrivial electronic states characterized by the non-zero Chern number and the edge states of nanoribbon.Our results offer versatile platforms for the realization of massless spintronics with full-spin polarization in 2D Cairo pentagonal Ni_(2)(TCNQ)_(2) Lattice.

A driven three-dimensional electric lattice for polar molecules

Three-dimensional(3D)driven optical lattices have attained great attention for their wide applications in the quest to engineer new and exotic quantum phases.Here we propose a 3D driven electric lattice(3D-DEL)for cold polar molecules as a natural extension.Our 3D electric lattice is composed of a series of thin metal plates in which two-dimensional square hole arrays are distributed.When suitable modulated voltages are applied to these metal plates,a 3D potential well array for polar molecules can be generated and can move smoothly back and forth in the lattice.Thus,it can drive cold polar molecules confined in the 3D electric lattice.Theoretical analyses and trajectory calculations using two types of molecules,ND3 and PbF,are performed to justify the possibility of our scheme.The 3D-DEL offers a platform for investigating cold molecules in periodic driven potentials,such as quantum computing science,quantum information processing,and some other possible applications amenable to the driven optical lattices.