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Articles 1 - 10 of 10
Full-Text Articles in Engineering
Spontaneous Symmetry Breaking And Linear Electrooptic Response In The Achiral Ferronematic Compound, Neelam Yadav, Yuri Panarin, Wanhe Jiang, Georg H. Mehl, J.K. Vij
Spontaneous Symmetry Breaking And Linear Electrooptic Response In The Achiral Ferronematic Compound, Neelam Yadav, Yuri Panarin, Wanhe Jiang, Georg H. Mehl, J.K. Vij
Articles
A compound with the constituent non-chiral molecules, DIO, known to exhibit three nematic subphases namely N, Nx and NF, is studied by polarizing microscopy as function of the alignment layers on one of the substrates, no alignment on any of the substrates, alignment layer on both substrates with parallel and antiparallel rubbing, different cell spacings. The cell with one alignment layer is also studied by electro-optics. N is found to be a conventional nematic phase, but it shows two additional unusual features: chiral domains of opposite chirality and the linear EO response to the applied signal under certain experimental conditions. …
Mid-Infrared Chiral Metsurface Coupling With Molecular Vibration, Md Shamim Mahmud
Mid-Infrared Chiral Metsurface Coupling With Molecular Vibration, Md Shamim Mahmud
Masters Theses
“The mid-infrared design of chiral metamaterial shows a tremendous absorption capability of infrared rays, and it has the significant application of circular dichroism based device development. Plasmon-phonon coupling is one of the application of metamaterial that provides a new path for tailoring the surface in the nanoscale, which is also applicable in molecules detection. It is possible to change the Plasmon-Phonon coupling strength not only through the chemical change of molecules but also by changing the metamaterial light-matter interaction property. So far, linearly polarized light shows the strong coupling between metamaterial and molecules. However, it is possible to observe strong …
Epitaxial Growth Of Semiconductors And Chiral Metal Surfaces Using Spin Coating And Electrodeposition, Meagan V. Kelso
Epitaxial Growth Of Semiconductors And Chiral Metal Surfaces Using Spin Coating And Electrodeposition, Meagan V. Kelso
Doctoral Dissertations
"The current primary methods for epitaxial growth are energy intensive, requiring high temperature or high vacuum to obtain quality thin films. This dissertation explores the solution process methods of electrodeposition and spin coating for growth of epitaxial thin films. First, a method is developed to directly electrodeposit epitaxial CH3NH3PbI3 perovskite for solar cells on single crystal Au by electrochemically reducing I2 in organic solution. Perovskite is a newly explored material for solar cells, and its efficiency may be further improved by increasing the crystalline order. Second, a study on epitaxially electrodeposited chiral metal surfaces …
Chiral Metamaterial-Based Microwave Sensors, Nantakan Wongkasem, Amornthep Sonsilphong, Mario Gonzalez
Chiral Metamaterial-Based Microwave Sensors, Nantakan Wongkasem, Amornthep Sonsilphong, Mario Gonzalez
Electrical and Computer Engineering Faculty Publications and Presentations
A significant resonance shift is found in both reflection and transmission coefficients from both parallel and perpendicular excitations in a helical structure. The responses from the perpendicular excitation show better sensitivity than those from the parallel excitation at 480 MHz-560 MHz for 0.2 circumference difference. Additional electromagnetic properties of a helical structure, such as chirality, optical rotatory dispersion and circular dichroism can also further combine to enhance the sensing performance.
A Fast Linear Electro-Optical Effect In A Non-Chiral Bent-Core Liquid Crystal, Yuri Panarin, S.P. Sreenilayam, J.K. Vij, A. Lehmann, C. Tschierske
A Fast Linear Electro-Optical Effect In A Non-Chiral Bent-Core Liquid Crystal, Yuri Panarin, S.P. Sreenilayam, J.K. Vij, A. Lehmann, C. Tschierske
Articles
We report the observation of an electro-optical effect for a linear rotation of the optical axis as function of the electric field in an achiral tilted bent-core liquid crystalline compound, in which 4-cyanoresorcinol bisbenzoate core is symmetrically terminated by long linear alkyl chains (n =16) on both ends. The linear electro-optic effect observed in this material is similar to the deformed helical ferroelectric liquid crystal (DHFLC) effect reported previously in a FLC material except that dimensions of the helical pitch differ by two orders of magnitude. In the chiral systems, the helical pitch usually lies on the scale of sub-optical …
Chiral-Like Tunneling Of Electrons In Two-Dimensional Semiconductors With Rashba Spin-Orbit Coupling, Yee Sin Ang, Zhongshui Ma, C Zhang
Chiral-Like Tunneling Of Electrons In Two-Dimensional Semiconductors With Rashba Spin-Orbit Coupling, Yee Sin Ang, Zhongshui Ma, C Zhang
Yee Sin Ang
The unusual tunneling effects of massless chiral fermions (mCF) and massive chiral fermions (MCF) in a single layer graphene and bilayer graphene represent some of the most bizarre quantum transport phenomena in condensed matter system. Here we show that in a two-dimensional semiconductor with Rashba spin-orbit coupling (R2DEG), the real-spin chiral-like tunneling of electrons at normal incidence simultaneously exhibits features of mCF and MCF. The parabolic branch of opposite spin in R2DEG crosses at a Dirac-like point and has a band turning point. These features generate transport properties not found in usual two-dimensional electron gas. Albeit its p Berry phase, …
Fabrication And Assembly Of Patchy Particles With Uniform Patches, Zhenping He
Fabrication And Assembly Of Patchy Particles With Uniform Patches, Zhenping He
Dissertations, Theses, and Capstone Projects
Patchy colloidal particles have been widely studied as the self-assembly building blocks to illustrate their potential for forming complex structures. The parameters affecting the final assembly structures include (i) patch size, shape, and number per particle, (ii) their relative positions, and (iii) the surface properties of the patch material. Recent computational studies have highlighted the impact of patch shape on assembly structure; however, there are only a limited number of methods that can provide control over patch shape and size. In this thesis, a template is introduced to the Glancing Angle Vapor Deposition method (GLAD) to create surface anisotropy on …
Chiral-Like Tunneling Of Electrons In Two-Dimensional Semiconductors With Rashba Spin-Orbit Coupling, Yee Sin Ang, Zhongshui Ma, C Zhang
Chiral-Like Tunneling Of Electrons In Two-Dimensional Semiconductors With Rashba Spin-Orbit Coupling, Yee Sin Ang, Zhongshui Ma, C Zhang
Faculty of Engineering and Information Sciences - Papers: Part A
The unusual tunneling effects of massless chiral fermions (mCF) and massive chiral fermions (MCF) in a single layer graphene and bilayer graphene represent some of the most bizarre quantum transport phenomena in condensed matter system. Here we show that in a two-dimensional semiconductor with Rashba spin-orbit coupling (R2DEG), the real-spin chiral-like tunneling of electrons at normal incidence simultaneously exhibits features of mCF and MCF. The parabolic branch of opposite spin in R2DEG crosses at a Dirac-like point and has a band turning point. These features generate transport properties not found in usual two-dimensional electron gas. Albeit its p Berry phase, …
Helical Ordering In Chiral Block Copolymers, Wei Zhao
Helical Ordering In Chiral Block Copolymers, Wei Zhao
Open Access Dissertations
The phase behavior of chiral block copolymers (BCPs*), namely, BCPs with at least one of the constituent block is formed by chiral monomers, is studied both experimentally and theoretically. Specifically, the formation of a unique morphology with helical sense, the H* phase, where the chiral block forms nanohelices hexagonally embedded in the matrix of achiral block, is investigated. Such unique morphology was first observed in the cast film of polystyrene-b-poly(L-lactide) (PS-b-PLLA) from a neutral solvent dichloromethane at room temperature with all the nanohelices being left-handed, which would switch to right-handed if the PLLA block changes to …
Determination Of Ibuprofen Isotherm Using Supercritical Fluid Chromatography, Loi Ho
Determination Of Ibuprofen Isotherm Using Supercritical Fluid Chromatography, Loi Ho
USF Tampa Graduate Theses and Dissertations
Chromatography is widely used to determine physiochemical properties data including adsorption isotherm. In the separation of enantiomers through sorptive processes, supercritical fluids allow efficient and green alternatives to liquid solvent based systems. The isotherm information is vital in the development of operating policies and design of preparative chromatographic or moving bed separation schemes. Determination of sorption isotherms from experimental chromatographic elution data is automated and compared with different chromatogram model. Procedures were developed and validated for separation of R- and S- ibuprofen with supercritical 〖CO〗_2 and ethanol mixture as the mobile phase over a chiral stationary phase. The isotherms for …