2,568 research outputs found
Parametric polynomial minimal surfaces of arbitrary degree
Weierstrass representation is a classical parameterization of minimal
surfaces. However, two functions should be specified to construct the
parametric form in Weierestrass representation. In this paper, we propose an
explicit parametric form for a class of parametric polynomial minimal surfaces
of arbitrary degree. It includes the classical Enneper surface for cubic case.
The proposed minimal surfaces also have some interesting properties such as
symmetry, containing straight lines and self-intersections. According to the
shape properties, the proposed minimal surface can be classified into four
categories with respect to , and . The explicit
parametric form of corresponding conjugate minimal surfaces is given and the
isometric deformation is also implemented
Bi-quartic parametric polynomial minimal surfaces
Minimal surfaces with isothermal parameters admitting B\'{e}zier
representation were studied by Cosin and Monterde. They showed that, up to an
affine transformation, the Enneper surface is the only bi-cubic isothermal
minimal surface. Here we study bi-quartic isothermal minimal surfaces and
establish the general form of their generating functions in the Weierstrass
representation formula. We apply an approach proposed by Ganchev to compute the
normal curvature and show that, in contrast to the bi-cubic case, there is a
variety of bi-quartic isothermal minimal surfaces. Based on the Bezier
representation we establish some geometric properties of the bi-quartic
harmonic surfaces. Numerical experiments are visualized and presented to
illustrate and support our results.Comment: 14 page
Numerical Simulations of Directed Self-Assembly Methods in Di-block Copolymer Films for Efficient Manufacturing of Nanoscale Patterns with Long-Range Order
Directed self-assembly (DSA) of block copolymers (BCPs) has been shown as a viable method to achieve bulk fabrication of surface patterns with feature sizes smaller than those available through traditional photolithography. Under appropriate thermodynamic conditions, BCPs will self-assemble into ordered micro-domain morphologies, a desirable feature for many applications. One of the primary interests in this field of research is the application of thin-film BCPs to existing photolithography techniques. This âbottom-upâ approach utilizes the self-assembled BCP nanostructures as a sacrificial templating layer in the lithographic process.
While self-assembly occurs spontaneously, extending orientational uniformity over centimeter-length scales remains a critical challenge. A number of DSA techniques have been developed to enhance the long range order in an evolving BCP system during micro-phase separation. Of primary interest to this dissertation is the synergistic behavior between chemoepitaxial templating and cold-zone annealing. The first method involves pre-treating a substrate with chemical boundaries that will attract or repel one of the monomer blocks before application of the thin-film via spin-coating. The second method applies a mobile, thermal gradient to induce micro-phase separation in a narrow region within the homogeneous thin-film .
Parametric studies have been performed to characterize the extent of long range order and defect densities obtained by applying various thermal zone velocities and template patterns. These simulations are performed by utilizing a Time-Dependent Ginzburg-Landau (TDGL) model and an optimized phase field (OPF) model. Parallel processing is implemented to allow large-scale simulations to be performed within a reasonable time period
Complexity of Model Testing for Dynamical Systems with Toric Steady States
In this paper we investigate the complexity of model selection and model
testing for dynamical systems with toric steady states. Such systems frequently
arise in the study of chemical reaction networks. We do this by formulating
these tasks as a constrained optimization problem in Euclidean space. This
optimization problem is known as a Euclidean distance problem; the complexity
of solving this problem is measured by an invariant called the Euclidean
distance (ED) degree. We determine closed-form expressions for the ED degree of
the steady states of several families of chemical reaction networks with toric
steady states and arbitrarily many reactions. To illustrate the utility of this
work we show how the ED degree can be used as a tool for estimating the
computational cost of solving the model testing and model selection problems
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