Two-dimensional Ones Research Articles

Physics of Core-Collapse Supernovae in Three Dimensions: A Sneak Preview

Nonspherical mass motions are a generic feature of core-collapse supernovae, and hydrodynamic instabilities play a crucial role in the explosion mechanism. The first successful neutrino-driven explosions could be obtained with self-consistent, first-principles simulations in three spatial dimensions. But three-dimensional (3D) models tend to be less prone to explosion than the corresponding axisymmetric two-dimensional (2D) ones. The reason is that 3D turbulence leads to energy cascading from large to small spatial scales, the inverse of the 2D case, thus disfavoring the growth of buoyant plumes on the largest scales. Unless the inertia to explode simply reflects a lack of sufficient resolution in relevant regions, some important component of robust and sufficiently energetic neutrino-powered explosions may still be missing. Such a deficit could be associated with progenitor properties such as rotation, magnetic fields, or precollapse perturbations, or with microphysics that could cause enhancement of neutrino heating behind the shock. 3D simulations have also revealed new phenomena that are not present in 2D ones, such as spiral modes of the standing accretion shock instability (SASI) and a stunning dipolar lepton-number emission self-sustained asymmetry (LESA). Both impose time- and direction-dependent variations on the detectable neutrino signal. The understanding of these effects and of their consequences is still in its infancy.

Reliable Equation of State for Composite Bosons in the 2D BCS-BEC Crossover

We briefly discuss recent experiments on the BCS-BEC crossover with ultracold alkali-metal atoms both in three-dimensional configurations and two-dimensional ones. Then we analyze the quantum-field-theory formalism used to describe an attractive D-dimensional Fermi gas taking into account Gaussian fluctuations. Finally, we apply this formalism to obtain a reliable equation of state of the 2D system at low temperaratures in the BEC regime of the crossover by performing a meaningful dimensional regularization of the divergent zero-point energy of collective bosonic excitations.

3D holographic head mounted display using holographic optical elements with astigmatism aberration compensation.

We propose a bar-type three-dimensional holographic head mounted display using two holographic optical elements. Conventional stereoscopic head mounted displays may suffer from eye fatigue because the images presented to each eye are two-dimensional ones, which causes mismatch between the accommodation and vergence responses of the eye. The proposed holographic head mounted display delivers three-dimensional holographic images to each eye, removing the eye fatigue problem. In this paper, we discuss the configuration of the bar-type waveguide head mounted displays and analyze the aberration caused by the non-symmetric diffraction angle of the holographic optical elements which are used as input and output couplers. Pre-distortion of the hologram is also proposed in the paper to compensate the aberration. The experimental results show that proposed head mounted display can present three-dimensional see-through holographic images to each eye with correct focus cues.

Efficient Reversible Data Hiding Based on Multiple Histograms Modification

Prediction-error expansion (PEE) is the most successful reversible data hiding (RDH) technique, and existing PEE-based RDH methods are mainly based on the modification of one- or two-dimensional prediction-error histogram (PEH). The two-dimensional PEH-based methods perform generally better than those based on one-dimensional PEH; however, their performance is still unsatisfactory since the PEH modification manner is fixed and independent of image content. In this paper, we propose a new RDH method based on PEE for multiple histograms. Unlike the previous methods, we consider in this paper a sequence of histograms and devise a new embedding mechanism based on multiple histograms modification (MHM). A complexity measurement is computed for each pixel according to its context, and the pixels with a given complexity are collected together to generate a PEH. By varying the complexity to cover the whole image, a sequence of histograms can be generated. Then, two expansion bins are selected in each generated histogram and data embedding is realized based on MHM. Here, the expansion bins are adaptively selected considering the image content such that the embedding distortion is minimized. With such selected expansion bins, the proposed MHM-based RDH method works well. Experimental results show that the proposed method outperforms the conventional PEE and its miscellaneous extensions including both one- or two-dimensional PEH-based ones.

Environmental noise control during its transmission phase to protect buildings. Design model for acoustic barriers based on arrays of isolated scatterers

A new generation of acoustic barriers is being introduced into the noise control market. These barriers, based on arrays of isolated scatterers, present interesting properties to be used in cities to reduce the transmitted transport noise affecting buildings. Among them, both aesthetic and continuity factors of the urban landscape may be mentioned. This new kind of barrier is technologically advanced and acoustically competitive with respect to the current ones formed by continuous rigid materials. To design these barriers whilst taking into account their inherent acoustic complexity, we present an overlapping numerical model here that enables us to split the real three-dimensional problem into two two-dimensional ones, allowing both the reduction of the computational cost and the separate analysis of each one of the noise control mechanisms involved. We analyse different cases, checking the numerical simulations with accurate experimental results.

Edge states of periodically kicked quantum rotors.

We present a quantum localization phenomenon that exists in periodically kicked three-dimensional rotors, but is absent in the commonly studied two-dimensional ones: edge localization. We show that under the condition of a fractional quantum resonance there are states of the kicked rotor that are strongly localized near the edge of the angular momentum space at J=0. These states are analogs of surface states in crystalline solids, and they significantly affect resonant excitation of molecular rotation by laser pulse trains.

Investigation of Rotational Diffusion of a Carbon Nanotube by Molecular Dynamics.

The rotational diffusion coefficient of a single carbon nanotube in fluid is calculated by equilibrium and nonequilibrium molecular dynamics (MD). The validity and accuracy of the MD simulations are checked on plenty of data points by varying the length and diameter of the nanotube. The three-dimensional (3D) coefficients are larger than the two-dimensional (2D) ones, both having non- negligible deviations from the theoretical predictions [J. Chem. Phys. 1984, 81, 2047-2052]. By changing the parameter εC-Ar of Lennard-Jones potential, the interaction strength between carbon and argon atoms is also taken into account. A monotonic decrease of the coefficients for both 2D and 3D cases with the increase of εC-Ar can be observed. Our present work suggests that we must be cautious when using the literature theory in practical situations.

Two-dimensional Continuous Attractors of Recurrent Neural Networks

In order to facilitate periodic membrane oscillations in brain, continuous attractors with periodic shape has been studied in the CANN. This paper will extend one-dimensional continuous attractors with periodic shape to two-dimensional ones in Recurrent Neural Networks (RNN). Under a certain condition, the RNN can possess the stable and unstable two-dimensional (2D) continuous attractors. Finally, a example is used to illustrate the 2D periodic continuous attractors.

Nonlocality distillation for high-dimensional correlated boxes

Most of the existing distillation protocols only work for binary-input binary-output nonlocal boxes (two-dimensional boxes), and they cannot be generalized to the binary-input multi-output nonlocal boxes (high-dimensional boxes) in a trivial way. We will design some comparator-based protocols to distill high-dimensional nonlocal boxes. Our protocols are more powerful and universal than the previous ones in the sense that they can distill the arbitrary-dimensional boxes rather than the limited two-dimensional ones. The initial nonlocalities and the wiring manners between the boxes are two main factors deciding the distillation efficiency.

HYDRODYNAMIC INSTABILITIES OF TWO VISCOELASTIC LIQUID SHEET MODELS IN AN INVISCID GAS MEDIUM

The instabilities of two viscoelastic liquid sheet models (of Walters B' and Rivlin-Ericksen types) issued in an inviscid gas medium have been separetely invistigated. The dispersion relations between the growth rate and wave number of both symmetric and antisymmetric disturbances are derived for both models, and solved numerically using a new technique. The effects of the Weber number, Ohnesorge number, gas-to-liquid density ratio, and viscoelasticity parameter on the growth rates of two-and three-dimensional disturbances in both models are studied. We conclude, at low values of the Weber number, that two-dimensional disturbances dominate the instability process for both symmetric and antisymmetric disturbances, whereas if the Weber number is high, symmetric three-dimensional disturbances become more unstable than two-dimensional ones only when the x-direction wave number is small. In the antisymmetric disturbances case for all various parameters, the two-dimensional instability disturbances are found to be more unstable than the three-dimensional ones. It is found, in both models, that the gas-to-liquid density ratio, Ohnesorge number and the viscoelasticity parameter have stabilizing effects on the considered system, while the Weber number has a destabilizing effect. It found also that the instabilities in the Walters B' liquid sheet occur faster than those in the Rivlin-Ericksen liquid sheet.

Efecto Talbot Unidimensional y Bidimensional

En este trabajo se muestran los resultados de los experimentos realizados en el verano del 2014 en el IPICYT, para corroborar la existencia del efecto Talbot el cual consiste en la reaparición de una imagen nítida de un objeto periódico iluminado por una fuente de luz cada cierta distancia después del objeto. Esta distancia se le conoce como distancia de Talbot y da la escala espacial de este fenómeno. Se utilizaron rejillas unidimensionales periódicas, aperiódicas y bidimensionales con estructura hexagonal, todas fueron creadas previamente con el programa grafico Adobe Illustrator con las frecuencias espaciales que se calcularon que darían una distancia de Talbot que permite la observación del efecto en el laboratorio. Las rejillas se iluminaron con un láser de He-Ne de longitud de onda de 633 nm (rojo) y posteriormente se localizó a que distancia se volvía a formar la auto-imagen de la rejilla.

3D buckling analysis of FGM sandwich plates under bi-axial compressive loads

Based on the Reissner mixed variational theorem (RMVT), finite rectangular layer methods (FRLMs) are developed for the three-dimensional (3D) linear buckling analysis of simply-supported, fiber-reinforced composite material (FRCM) and functionally graded material (FGM) sandwich plates subjected to bi-axial compressive loads. In this work, the material properties of the FGM layers are assumed to obey the power-law distributions of the volume fractions of the constituents through the thickness, and the plate is divided into a number of finite rectangular layers, in which the trigonometric functions and Lagrange polynomials are used to interpolate the in- and out-of-plane variations of the field variables of each individual layer, respectively, and an h-refinement process is adopted to yield the convergent solutions. The accuracy and convergence of the RMVT-based FRLMs with various orders used for expansions of each field variables through the thickness are assessed by comparing their solutions with the exact 3D and accurate two-dimensional ones available in the literature.

J0570204 運動量と熱輸送の非相似性の最大化([J057-02]乱流における運動量,熱,物質の輸送現象(2))

Using a variational method, two- and three-dimensional incompressible steady velocity fields are numerically determined so that they can maximize the dissimilarity between heat transfer and momentum transfer in plane Couette flow. The Prandtl number is set to be unity, and the same boundary conditions are imposed on the velocity and temperature fields. The Stanton number (heat transfer) and friction coefficient (momentum transfer) for the two-dimensional (streamwise-independent or spanwise-independent) optimal states and the three-dimensional optimal state are compared with those for a corresponding turbulent state. In spite of the similar configuration of the velocity and the temperature, not only the three-dimensional optimal but the two-dimensional ones are found to achieve the much larger Stanton number and the less friction coefficient than the turbulent state.

A Mathematical Design of Genetic Operators onGLn(ℤ2)

We study the space that consists of all nonsingular binary matrices, that is,GLn(ℤ2). The space is quite important in that it is used for the change of basis in binary representation, which is the encoding typically adopted in genetic algorithms. We analyze the properties ofGLn(ℤ2)and theoretically design possible encodings and their corresponding recombination operators for evolutionary algorithms. We present approaches based on elementary matrices of linear algebra as well as typical two-dimensional ones.

Two-dimensional zymography in detection of proteolytic enzymes in wheat leaves

Proteolytic enzymes in wheat leaves were studied using zymographic detection of enzyme activities on one-way (1D) SDS-polyacrylamide gels and two-dimensional (2D) ones, on which protein samples were isoelectrofocused prior to PAGE separation. Gelatin of concentration 0.1 %, copolymerized into SDS-PAGE gels, digested by active proteinases enabled detection of those enzymes. On 1D gels, seven bands were seen and assigned to particular families through the use of specific inhibitors. Metalloproteinases inhibited by 20 mM EDTA were detected as 150 kDa band; aspartic proteinases were assigned to 115–118 kDa double band by using 25 mM pepstatin; 10 mM phenylmethylsulfonyl fluoride used for detection of serine proteinases pointed to band of 70 kDa and finally due to 10 μM E-64 inhibitor, cysteine proteinases of 37 and 40 kDa were detected. On 2D gels, additional separation according to protein isoelectric points enabled detection of proteinase isoforms. In the range of 4.5–6 pI, six metalloproteinases as well as ten aspartic proteinases were visible, ten serine- isoforms of pI 4.5–6.8 and four cysteine proteinases of 4.5–5.0 pI were found. Presented results were detected as reproducible results observed at least in four independent biological replications.

Three-dimensional Detection Method for Bridge Surface Defects Based on Line-shaped Lasers

AbstractThe measurement and description of the three-dimensional (3D) parameters of bridge surface defects are common technical problems in the field of bridge defect detection. These problems are difficult to solve through conventional methods. However, with the assistance of line-shaped lasers, 3D structure measurements can be converted to two-dimensional ones. Based on an analysis of the applications of 3D measurement techniques in other industries, a 3D measurement method for bridge surface defects is proposed. In this method, the parameters of line deformation are measured using digital imaging and pattern recognition techniques, and then the 3D parameters of bridge surface defects are calculated. The computational formula is also deduced. Subsequently, the feasibility of the method is verified by experiments.

Quantitative evaluation of the fetal cerebellar vermis using the median view on three‐dimensional ultrasound

The purpose of this study was to investigate the effectiveness for quantitative evaluation of cerebellar vermis using three-dimensional (3D) ultrasound and to establish a nomogram for Chinese fetal vermis measurements during gestation. Sonographic examinations were performed in normal fetuses and in cases suspected of the diagnosis of vermian rotation. 3D median planes were obtained with both OMNIVIEW and tomographic ultrasound imaging. Measurements of the cerebellar vermis were highly correlated between two-dimensional and 3D median planes. The diameter of the cerebellar vermis follows growth approximately predicted by the quadratic regression equation. The normal vermis was almost parallel to the brain stem, with the average angle degree to be <2° in normal fetuses. The average angle degree of the 9 cases of vermian rotation was >5°. Three-dimensional median planes are obtained more easily than two-dimensional ones, and allow accurate measurements of the cerebellar vermis. The 3D approach may enable rapid assessment of fetal cerebral anatomy in standard examination. Measurements of cerebellar vermis may provide a quantitative index for prenatal diagnosis of posterior fossa malformations.

Positional isomeric effect on structural diversity of Zn(II) coordination polymers based on positional isomers and tetrahedral linker and pyridine-2,6-dicarboxylic acid

To systematically investigate the influence of the positional isomeric effect on the structures of their complexes, we prepared two Zn(II) complexes [Zn4(L1)(PDC)4]·5H2O and [Zn2(L2)2(PDC)2]·3H2O based on a couple of tetrahedral linkers (L1=tetrakis(4-pyridyloxymethylene)methane; L2=tetrakis(3-pyridyloxymethylene)methane) in the presence of the carboxylate linkers (PDC=pyridine-2,6-dicarboxylic acid). Their structures and properties can be tuned by variable N-donor positions of the tetrahedral isomers. The X-ray crystallographic analysis demonstrate three-dimensional ones of complex 1 and two-dimensional ones of complex 2. This work indicates that isomeric effect of the couple of isomers play an important role in the construction of the Zn(II) complexes. In addition, their thermostability and photoluminescence are also reported in detail.

Geometrical properties of multilayer nano-imprint-lithography molds for optical applications

The functionality of micro- and nano-optical devices can be increased by using three-dimensional structures instead of two-dimensional ones. This paper reports on a fabrication method for nano-imprint lithography molds for planar optical applications which exhibit two different height levels with large pattern diversity as various lithographic technologies can be applied. To ensure a proper operation of optical elements as waveguides, a precise control of the feature dimensions is essential. The lateral and depth resolution as well as the alignment of two structure height levels have been investigated. The results show the feasibility of the process to obtain single-mode operating waveguides and micro-ring resonator structures for sensor applications. The replication of these structures has been performed in a UV-curable polymer. A residual layer could be avoided using non-wetting perfluoropolyether polymer molds cast from the original ones used in a reverse nano-imprint setup.

Spectral Properties of Superlattices with Anisotropic Inhomogeneities. The Transition from 3D to 2D Disorder

Waves in superlattice (SL) contained inhomogeneities with anisotropic correlation properties are considered. The anisotropy of the correlation during the transition from 3D to 2D disorder is characterized by the parameter , where and are the correlation wave numbers along the axis of the SL and in the plane of the its layers, respectively ( and are the correlation radii). Dependencies of both the dynamic susceptibility and density of states at the continuous transition from the isotropic three-dimensional inhomogeneities () to the two-dimensional ones () have been obtained.