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The ability to establish significant phase modulation at low applied field provides a promising route toward polarization control and wavefront shaping for liquid-crystal-based devices. Owing to the polarization-selective reflectivity of chiral liquid crystals (CLCs), reflective wavefront shaping via geometric phase is demonstrated when a circularly polarized light is Bragg reflected by a spatially orientated chiral layer. Nowadays, photoresponsive CLCs have attracted extensive attention due to their exotic feature that endows the CLC devices with the capability of electric-free remote control. Despite the mature photoresponsive CLC materials and the sophisticated reflective geometric phase devices, a light-induced topological optical phase modulation for a transmissive wave exiting a CLC cell remains elusive. Here, with the employment of a photosensitive chiral dopant, a hybrid aligned photoresponsive CLC system, demonstrating the simultaneous light modulation of topological geometric phase and dynamic phase via helical pitch manipulation is established. The continuous dual-phase modulation engenders a smooth optically controllable diffraction efficiency (i.e., from 90%) of the proposed light-reconfigurable CLC geometric phase optical element prototypes with multistable diffractive behavior, thus launching a paradigm shift for the application of novel liquid-crystal photonic devices in the field of all-optical polarization and spin processing.

Future HIV-1 curative therapies require a thorough understanding of the distribution of genetically-intact HIV-1 within T-cell subsets during antiretroviral therapy (ART) and the cellular mechanisms that maintain this reservoir. Therefore, we sequenced near-full-length HIV-1 genomes and identified genetically-intact and genetically-defective genomes from resting naive, stem-cell memory, central memory, transitional memory, effector memory, and terminally-differentiated CD4+ T-cells with known cellular half-lives from 11 participants on ART. We find that a higher infection frequency with any HIV-1 genome was significantly associated with a shorter cellular half-life, such as transitional and effector memory cells. A similar enrichment of genetically-intact provirus was observed in these cells with relatively shorter half-lives. We found that effector memory and terminally-differentiated cells also had significantly higher levels of expansions of genetically-identical sequences, while only transitional and effector memory cells contained genetically-intact proviruses that were part of a cluster of identical sequences. Expansions of identical sequences were used to infer cellular proliferation from clonal expansion. Altogether, this indicates that specific cellular mechanisms such as short half-life and proliferative potential contribute to the persistence of genetically-intact HIV-1. IMPORTANCE The design of future HIV-1 curative therapies requires a more thorough understanding of the distribution of genetically-intact HIV-1 within T-cell subsets as well as the cellular mechanisms that maintain this reservoir. These genetically-intact and presumably replication-competent proviruses make up the latent HIV-1 reservoir. Our investigations into the possible cellular mechanisms maintaining the HIV-1 reservoir in different T-cell subsets have revealed a link between the half-lives of T-cells and the level of proviruses they contain. Taken together, we believe our study show

Future HIV-1 curative therapies require a thorough understanding of the distribution of genetically-intact HIV-1 within T-cell subsets during antiretroviral therapy (ART) and the cellular mechanisms that maintain this reservoir. Therefore, we sequenced near-full-length HIV-1 genomes and identified genetically-intact and genetically-defective genomes from resting naive, stem-cell memory, central memory, transitional memory, effector memory, and terminally-differentiated CD4+ T-cells with known cellular half-lives from 11 participants on ART. We find that a higher infection frequency with any HIV-1 genome was significantly associated with a shorter cellular half-life, such as transitional and effector memory cells. A similar enrichment of genetically-intact provirus was observed in these cells with relatively shorter half-lives. We found that effector memory and terminally-differentiated cells also had significantly higher levels of expansions of genetically-identical sequences, while only transitional and effector memory cells contained genetically-intact proviruses that were part of a cluster of identical sequences. Expansions of identical sequences were used to infer cellular proliferation from clonal expansion. Altogether, this indicates that specific cellular mechanisms such as short half-life and proliferative potential contribute to the persistence of genetically-intact HIV-1. IMPORTANCE The design of future HIV-1 curative therapies requires a more thorough understanding of the distribution of genetically-intact HIV-1 within T-cell subsets as well as the cellular mechanisms that maintain this reservoir. These genetically-intact and presumably replication-competent proviruses make up the latent HIV-1 reservoir. Our investigations into the possible cellular mechanisms maintaining the HIV-1 reservoir in different T-cell subsets have revealed a link between the half-lives of T-cells and the level of proviruses they contain. Taken together, we believe our study show

Cheng-Zong Li,1–3,* Xiao-Jie Jiang,1,2,* Bin Lin,1,2 Hai-Jie Hong,1,2 Si-Yuan Zhu,1,2 Lei Jiang,1,2 Xiao-Qian Wang,1 Nan-Hong Tang,1 Fei-Fei She,2 Yan-Ling Chen1,2 1Department of Hepatobiliary Surgery and Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou, People’s Republic of China; 2Key Laboratory of the Ministry of Education for Gastrointestinal Cancer and Key Laboratory of Tumour Microbiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, People’s Republic of China; 3Department of General Surgery, The Second Affiliated Hospital Of Fujian Medical University, Quanzhou, People’s Republic of China *These authors contributed equally to this work Background: Tumor necrosis factor alpha (TNF-α) enhances lymphangiogenesis in gallbladder carcinoma (GBC) via activation of nuclear factor (NF-κB)-dependent vascular endothelial growth factor-C (VEGF-C). Receptor-interacting protein 1 (RIP1) is a multifunctional protein in the TNF-α signaling pathway and is highly expressed in GBC. However, whether RIP1 participates in the signaling pathway of TNF-α-mediated VEGF-C expression that enhances lymphangiogenesis in GBC remains unclear. Methods: The RIP1 protein levels in the GBC-SD and NOZ cells upon stimulation with increasing concentrations of TNF-α as indicated was examined using Western blot. Lentiviral RIP1 shRNA and siIκBα were constructed and transduced respectively them into NOZ and GBC-SD cells, and then PcDNA3.1-RIP1 vectors was transduced into siRIP1 cell lines to reverse RIP1 expression. The protein expression of RIP1, inhibitor of NF-κB alpha (IκBα), p-IκBα, TAK1, NF-κB essential modulator were examined through immunoblotting or immunoprecipitation. Moreover, VEGF-C mRNA levels were measured by quantitative real-time polymerase chain reac

PT-symmetric quantum mechanics, the extension of conventional quantum mechanics to the non-Hermitian Hamiltonian invariant under the combined parity (P) and time reversal (T) symmetry, has been successfully applied to a variety of fields such as solid state physics, mathematical physics, optics, quantum field theory. Recently, the extension of PT-symmetrical theory to entangled quantum systems was challenged in that PT formulation within the conventional Hilbert space violates the no-signaling principle. Here, we revisit the derivation of non-signaling principle in the framework of PT inner product prescription. Our results preserve the no-signaling principle for a two-qubit system, reaffirm the invariance of the entanglement, and reproduce the Clauser-Horne-Shimony-Holt (CHSH) inequality. We conclude that PT-symmetric quantum mechanics satisfies the requirements for a fundamental theory and provides a consistent description of quantum systems., Comment: 13 pages, will appear in Journal of Physics A: Mathematical and Theoretical

PT-symmetric quantum mechanics, the extension of conventional quantum mechanics to the non-Hermitian Hamiltonian invariant under the combined parity (P) and time reversal (T) symmetry, has been successfully applied to a variety of fields such as solid state physics, mathematical physics, optics, quantum field theory. Recently, the extension of PT-symmetrical theory to entangled quantum systems was challenged in that PT formulation within the conventional Hilbert space violates the no-signaling principle. Here, we revisit the derivation of non-signaling principle in the framework of PT inner product prescription. Our results preserve the no-signaling principle for a two-qubit system, reaffirm the invariance of the entanglement, and reproduce the Clauser-Horne-Shimony-Holt (CHSH) inequality. We conclude that PT-symmetric quantum mechanics satisfies the requirements for a fundamental theory and provides a consistent description of quantum systems., Comment: 13 pages, will appear in Journal of Physics A: Mathematical and Theoretical

Isolation of single-walled carbon nanotubes (SWNTs) remains to be a key step for realization of the true potential of SWNTs, since the physical properties of SWNTs are dependent on the tube s chirality index (n, m). Polymers with enhanced helical conformation are found to be an efficient sorting mechanism for SWNTs, as the cavity of polymer s helical conformation can be tailored to facilitate an intimate interaction between polymer and SWNTs. Poly[(m-phenylenevinylene) (PmPV) demonstrates that the polymer helical conformation can be controlled to sort the SWNTs by their diameters. Poly[(m-phenyleneethynylene)-alt-(p-phenyleneethynylene)] (PPE) reveals the intriguing selectivity toward tube (6,5), illustrating the impact of carbon-carbon triple bonds on the SWNTs selectivity. In another approach, polyethyleneimine (PEI) is found to exhibit selective interaction with semiconducting SWNTs. By using this property, cellulose impregnated with PEI is found to be a column packing materials for separation of metallic SWNTs from a raw HiPco sample. Analysis by AFM, 2D fluorescence and UV-vis-NIR absorption spectra suggests that the metallic SWNTs (13,4) can be separated from the armchair SWNTs (10,10) and (9,9)., The original document contains color images. Prepared in collaboration with the Department of Physics, Clark Atlanta University, Atlanta, GA and the University of Tennessee, Knoxville.

The fast switchable Fresnel zone lens with relatively high efficiency and easy fabrication procedure was studied in this article. As compared with ordinary Fresnel zone plate (FZP), our proposed Fresnel zone lens (see FIG. 1) had double light intensity at the focal point, thus possessed double efficiency of ordinary FZP.

The fast switchable Fresnel zone lens with relatively high efficiency and easy fabrication procedure was studied in this article. As compared with ordinary Fresnel zone plate (FZP), our proposed Fresnel zone lens (see FIG. 1) had double light intensity at the focal point, thus possessed double efficiency of ordinary FZP.

The fast switchable Fresnel zone lens with relatively high efficiency and easy fabrication procedure was studied in this article. As compared with ordinary Fresnel zone plate (FZP), our proposed Fresnel zone lens (see FIG. 1) had double light intensity at the focal point, thus possessed double efficiency of ordinary FZP.

In an effort to develop efficient O(N) first-principles calculation algorithms, we devised the approach using wavelets as basis functions of electronic structure calculation. The theory of wavelets allows one to apply a multi-scale (multiresolution) analysis to problems that exhibit widely varying length scales. Furthermore, the dual localization property of the wavelet basis is useful for improving the existing (N) methods that are yet based solely on the real-space locality. Our application O this idea to the density-functional molecular dynamics method leads to a robust algorithm, which holds potential to extend the applicability of the current first-principles methods to systems an order of magnitude large. On the other hand, we have developed an approach to the development of reliable "pair-functional" interatomic potentials for monoatomic metals based on fitting to a large set of experimental and ab initio data. In connection with the construction of improved and accurate semi-empirical models, we have investigated the simulation tools such as hyper-Molecular Dynamics, generalized simulated annealing for global optimization, finite-difference method for calculating non-linear static third-order polarizabilities.

The researchers have developed parallel and distributed algorithms for classical molecular dynamics and first-principles molecular dynamics methods for electronic structure calculations. An effective multivariable optimization scheme is employed for the construction of semi-empircal models. An innovative approach to apply the wavelet theory to electronic structure calculations is devised and implemented. A new iterative approach for solving quantum chemistry problems is discovered and tested for prototype atomic and molecular systems. In addition, a finite field method for calculating non-linear optical properties of molecules is developed and applied to the study of third-order polarizability of carbon-cage fullerenes. These developments in parallel and distributive algorithms have greatly enhanced the efficiency of simulating material properties. Moreover, under the support of the grant, three graduate students have completed their thesis, one for Ph.D, and two others for M.S.

In this report we summarize the progress to date, including the implementation of Message Passing Interface (MPI) standard on local supercomputers (Cray and powerful workstations); the development of an integrated simulation environment based on distributive computing; the application of a parallel meolecular dynamics algorithm; the formation of the research team; and finally, a brief list of research performed in this four-month period.

Tight-binding molecular dynamics is a semi-empirical method that has been used successfully in describing the properites of covalent-bonded semiconductor materials. This approach is based on the semi-empirical tight-binding model for electronic effects (quantum mechanical) and classical molecular dynamics for atoms (classical). This work focuses on a system- aticalreview and a specific implementation of the tight-binding molecular dynamics method, using recently developed molecular dynamic simulated annealing (Car-Parrinello) and density-matrix renormalization algorithm. The above methods scales as N2 and N, respectively, in comparison with the standard diagonalization method that scales as N3, where N is the numbers of atoms in the system. These algorithms are tested on silicon clusters. Silicon is an important material widely used in electronic technology. The study of the electronic properties of the silicon clusters provides useful test of the tight-binding algo-rithms, specifically the calculation of the forces from tight-binding quantum mechanics.

Numerical solutions of quantum mechanical problems have witnessed tremendous advances over the past years. In this thesis, we develop an iterative approach to problems of double-well potentials and their variants with parity-time-reversal symmetry- breaking perturbations. We show that the method provides an efficient scheme for obtaining accurate energies and wave functions. We discuss in this thesis potential applications to a variety of related topics such as phase transitions, symmetry breaking, and external field-induced effects. KEY TERMS: Quantum Mechanics, Energy, Symmetry, Physical Sciences and Mathematics, Physics, Quantum Physics

This thesis includes work done on graphene-based materials, examining their unique electronic properties using first-principles density-functional calculations. Abinitio methods such as density functional theory (DFT) are widely accepted as computational methods in condensed matter and materials physics. We begin by studying the electronics properties of graphene intercalation compounds (GICs). In order for bilayer graphene to be used for field effect transistors, the GIC must decouple the adajent graphene layers and decrease interlayer interaction. We conducted a theoretical study in order to elucidate the electronic characteristics of methane intercepted bilayer graphene under a perpendicularly applied electric field. We show that methane intercalated graphene can make a promising material for implimentations of graphene based field effect transistors since it has a controllable band gap. Finally, we show the evolution of band structure of graphene treated with fluorinated olefins through covalent functionalization. The bonding of fluorine to the graphene surface results in the transformation of orbital hybridization from sp2 to sp3. We find that the modification of graphene's electronic properties by such a drastic change in hybridization can lead to the elimination of the bands near the Fermi level and the opening of a band gap. We hope this work will help bring to light the promising electronic properties of graphene based materials for future device applications.

The binding of radical groups such as hydrogen, hydroxyl, epoxide, or fluorine to the graphene surface, forms covalent bonds and transforms the trigonal sp2 orbital to the tetragonal sp3 orbital. Such a transformation drastically modifies electronic properties, which leads to the opening of a bandgap through the removal of the bands near the Fermi level of the pristine graphene. We have investigated the structural, electronic, magnetic, and vibrational properties of functionalized graphene based on first-principles densityfunctional calculations. A twist-boat conformation is identified as the energetically most favorable nonmetallic configuration for fully oxidized graphene. The calculated Raman G-band blue shift is in very good agreement with experimental observations. A detailed analysis of fluorographene membranes indicates that there exist prominent chair and stirrup conformations, which correlate with the experimentally observed in-plane lattice expansion contrary to a contraction in graphane. The optical response of fluorographene is investigated using the GW-Bethe-Salpeter equation approach. The results are in good conformity with the experimentally observed optical gap and reveal predominant chargetransfer excitations arising from strong electron-hole interactions. The appearance of bounded excitons in the ultraviolet region can result in an excitonic Bose-Einstein condensate in fluorographene. Hydrogenated epitaxial graphene has distinctive electronic properties compared to the two-sided hydrogenated graphene. The stability of a given hydrogenation pattern is strongly influenced by the amount of sp2-hybridized bonding in the structure. A trigonal planar networked hydrogenation pattern is identified as an intrinsic ferromagnetic semiconductor, which is in good conformity with experimental observations. The electronic structure of graphite and rotational-stacked multilayer epitaxial graphene as a function of the applied electric bias is investigated using dis

Tumor protein p53 is a tumor suppressor that binds to a specific DNA sequence and trans-activates target genes leading to cell cycle arrest and/or apoptosis. p53, encoded by the human gene TP53, is a stress response protein that functions primarily as a tetrameric transcription factor, that regulates a large number of genes in response to a variety of cellular insults, including oncogene activation and DNA damage. Mutations in p53 are common in human cancer types. In order to study mutations in p53, 1TSR a wild type is selected along with four mutated proteins. The minimized conformation energy for the wild type and mutated proteins are calculated by simulated annealing using molecular dynamics simulations. The results show significant differences between hotspot mutations and the wild type in the minimized conformation energies using simulated annealing method. Based on the molecular dynamics, we have defined a correlation between molar masses of the target residue along with its two nearest neighbors to predict energy of a mutated protein respect to the wild type. Our results are in conformity with observations in the rate of mutation in biology.

We have revisited the general constructing schemes for a large family of stable hollowboron fullerenes with 80 + 8n (n = 0,2,3,...) atoms. In contrast to the hollow pentagon boron fullerenes with 12 hollow pentagons, the stable boron fullerenes constitute 12 filled pentagons and 12 additional hollow hexagons, which are more stable than the empty pentagon boron fullerenes including the magic B80 buckyball. Based on results from first-principles density-functional calculations, an empirical rule for filled pentagons is proposed along with a revised electron counting scheme to account for the improved stability and the associated electronic bonding feature. We have also studied the relative stability of various boron fullerene structures and structural and electronic properties of B80 bucky ball and boron nanotubes via dispersion-corrected density-functional calculations. Our results reveal that the energy order of fullerenes strongly depends on the exchange-correlation functional employed in the calculation and the vibrational stability for the icosahedral B80 with the inclusion of dispersion corrections, in contrast to the instability to a tetrahedral B80 with puckered capping atoms from preceding density functional theory calculations. Similarly, the dispersion-corrected density-functional calculations yield non-puckered boron nanotube conformations and an associated metallic state for zigzag tubes. A systematic study elucidates the importance of incorporating dispersion forces to account for the intricate interplay of two and three centered bonding in boron nanostructures.

Bender and Boettcher explored a quantum theory based on a non-Hermitian PT symmetric Hamiltonian , where PT is the operator of the space-time reflection and demonstrated that the PT-symmetric Hamiltonian can possess entirely real spectra. In this thesis, we point out that in the framework of PT-symmetric quantum mechanics; the calculation of matrix elements in the Hilbert space is ill-defined. We point out the importance of using CPT inner product in PT-symmetric systems. We manifested our assessment using the CPT inner product prescription for the entangled wave function of the composite system. We show that for a composite system with a local PT-symmetry, it preserves the no-signaling condition and the orthogonality of the states.The reduced density matrix is diagonal and independent of the non-Hermitian parameter . We reaffirm the consistency of PT-symmetric quantum mechanics as a candidate for a fundamental theory .

The structural and electronic properties of covalently and non-covalently functionalized graphene are investigated by means of first-principles density-functional-theory. The electronic characteristics of non-covalently functionalized graphene by a planar covalent organic framework (COF) are investigated. The aromatic central molecule of the COF acts as an electron donor while the linker of the COF acts as an electron acceptor. The concerted interaction of donor acceptor promotes the formation of planar COF networks on graphene. The distinctive electronic properties of covalently functionalized fluorinated epitaxial graphene are attributed to the polar covalent CF bond. The partial ionic character of the CF bond results in the hyperconjugation of CF ?-bonds with an sp2 network of graphene. The implications of resonant-orbital-induced doping for the electronic and magnetic properties of fluorinated epitaxial graphene are discussed. Isolation of single-walled carbon nanotubes (SWNTs) with specific chirality and diameters is critical. Water-soluble poly [(m- phenyleneethynylene)- alt- (p- phenyleneethynylene)], 3, is found to exhibit high selectivity in dispersing SWNT (6,5). The polymers ability to sort out SWNT (6,5) appears to be related to the carboncarbon triple bond, whose free rotation allows a unique assembly. We have also demonstrated the important role of dispersion forces on the structural and electronic stability of parallel displaced and Y-shaped benzene dimer conformations. Long-range dispersive forces play a significant role in determining the relative stability of benzene dimer. The effective dispersion of SWNT depends on the helical pitch length associated with the conformations of linkages as well as ?-? stacking configurations. We have revisited the constructing schemes for a large family of stable hollow boron fullerenes with 80 + 8n (n = 0,2,3,...) atoms. In contrast to the hollow pentagon boron fullerenes the stable structures constitute 12 filled

Bulk phonon spectra for several noble metals have been investigated, and the results are being reported in this thesis. The parameters appearing in the semi empirical glue model, are fitted to several physical properties of the noble metals. The calculation of the surface structure and dynamics of (100), (110), and (111) surfaces of aluminum using molecular dynamics and an empirical many body interatomic potential is presented. The multilayer relaxation of these surfaces was calculated by use of simulated annealing. Surface phonon spectra at finite, low temperatures was calculated by means of time-dependent correlation functions. Results are compared with experimental measurements and other calculations.

Game theory is the study of strategic competition used in many branches of science. In general, a game is a match between two or more players and each wants to maximize his or her score. In a game, the players score depends on their strategies. The goal is to find the optimized decision, with regard to the payoff, in conformity with the rules of the game. This thesis considers the games with two players who know both their own and their rivals payoff. However, they do not know the strategy chosen by the opponent In a classical game, the options of players are referred to as cooperation and defect. Quantum game theory is a generalization of classical game theory. In quantum games a linear combination of two options specify the strategy based on qubit. The quantum domain is characterized by entanglement. The quantum entanglement coefficient (y) varies from 0 to . The game is in the classical regime when y is smaller than a threshold. Quantum entanglement is intrinsically non-local. In an iterated game tournament, 63 different strategies contest with four known strategies. Depending on the result, they are divided to a number of groups. The competition specifies which group of strategies can obtain a higher score. Other types of games are discussed in the thesis. They are known as incomplete information games. In these games one player has two payoff matrixes, and the rival does not know which of them is used. We discuss the advantage of using quantum strategy over the classical game, particular in avoiding the dilemma in classical games.

In this thesis, energy levels, lifetimes, oscillator strengths and transition probabilities of Mg VII have been calculated. The Hartree-Fock (HF) and Multiconfiguration Hartree-Fock (MCHF) methods were used in the calculations of these atomic properties. We have included relativistic operators mass correction, spin-orbit interaction, one body Darwin term and spin-other-orbit interaction in the Breit-Pauli Hamiltonian. The configurations, (1s2)2s22p2, 2s2p3,2p4, 2s22p3s, 2s22p3p,2s2p2(4P)3s and 2s22p3d which correspond to 52 fine-structure levels, were included in the atomic model for the Mg VII ions. The present results have been compared with NIST compilation and other theoretical results, and generally a good agreement was found. KEY TERMS: Atomic Structure, Atomic Physics, Atomic, Molecular and Optical Physics, Physics, Quantum Physics

In this dissertation we discuss the electronic properties, structural configurations, and reaction mechanisms of chemically functionalized graphene and charged atomic metals. In general, we analyze fundamental atomic scale and nanoscale systems with density functional theory in order to investigate chemical reaction energetics for peroxide synthesis as well as methanol production without carbon emission. These systems were found to be tunable via the addition of cationic and anionic charges, change in transition metal type, and modification through chemical functionalization. Furthermore, transition state theory was used to predict an optimal configuration for chemically functionalized graphene, efficient use of anionic atomic gold and palladium for synthesis of water to peroxide, and clean conversion of methane to methanol without carbon dioxide emission utilizing anionic gold. KEY TERMS: graphene, tunable, catalysis, density functional theory, gold, palladium, Biological and Chemical Physics

Poly(ethylene oxide)-poly(styrene)-poly(ethylene oxide) triblock copolymer with di-hydroxyl terminated groups (HO-PEO-PS-PEO-OH) was conjugated with nitrilotriacetic acid (NTA) via esterification reaction using N,N'-Dicyclohexylcarbodiimide (DCC), 4-Dimethylaminopyridine (DMAP) and Dimethylformamide (DMF) as a solvent at 80 ?C. The poly(ethylene oxide)-poly(styrene)-poly(ethylene oxide) with NTA end groups (NTA-PEO-PS-PEO-NTA) was characterized and structure confirmed by 1H NMR, 13C NMR, and FT-IR spectroscopies. Thermogravimetric analysis (TGA) was carried out to investigate the thermal stability of the starting triblock copolymer poly(ethylene oxide)-poly(styrene)-poly(ethylene oxide) with di-hydroxyl terminated groups (HO-PEO-PS-PEO-OH) and the conjugated poly(ethylene oxide)-poly(styrene)-poly(ethylene oxide) functional polymer (NTA-PEO-PS-PEO-NTA). Surface morphologies of the (HO-PEO-PS-PEO-OH) and (NTA-PEO-PS-PEO-NTA) were studied by atomic force microscopy. In addition, the size distributions were determined using dynamic light scattering. The thermal behavior of the (HO-PEO-PS-PEO-OH) and (NTA-PEO-PS-PEO-NTA) were examined by differential scanning calorimetry (DSC). DSC thermograms indicate the formation of a two phase polymer matrix. The poly(ethylene oxide)-poly(styrene)-poly(ethylene oxide) with NTA functionalized end groups (NTA-PEO-PS-PEO-NTA) was bound or chelated with Ni(II) metal ion. The binding studies were carried out by ultraviolet-visible (UV-Vis) spectroscopy. The electronic behaviors of PEO-b-PS-b-PEO/ PS/ NTA-PEO-b-PS-b-PEO-NTA with ratio (1/5/1) and PEO-b-PS-b-PEO/ PS/ NTA-PEO-b-PS-b-PEO-NTA-Ni containing 1% of oxidized single-walled carbon nanotubes (SWCNTs) were investigated by IV plots from Kelvin sensing. The IV plots before sensitizing with protein varied from the IV plots after binding with protein indicating that the composites may be used as active components in biosensors. KEYWORDS: Materials Chemistry, Polymer Chemistry

Recent experimental work reported the synthesis, isolation and characterization of a Russian-doll-style endohedral fullerene, encompassing a carbon dimer within a scandium tetrahedron, all encased by a C80 cage. We have first investigated the equilibrium conformations and the associated charge transfer of the endohedral fullerene Sc4C2C80 based on first-principles density functional calculations; and secondly its electronic properties based on first-principles density functional calculations coupled with many-body GW correction. In the first part our results show that a distorted tetrahedron Sc4 cluster enfolding around the C2 dimer has the desired electronic structure that leads to efficient charge transfer to the open-shell icosahedral C80. A detailed analysis of the charge transfer between the Sc4C2 configurations and the icosahedral C80 cage indicate that the structural stability of the Russian-doll structured Sc4C2@C80 can be attributed to the donor-acceptor effects. In the second part, the calculation results yield a GW rectified gap of 1.8 eV for the Russian-doll structured Sc4C2@C80, in very good conformity with experimental observed value of 1.6 eV. The calculated electronic characteristics of the Russian-doll fullerene reveal distinct shell structures which are embellished in the GW approach. The analysis of vibrational frequency demonstrates profound hybridizations associated with the interactions between the Sc4C2 core and the C80 shell.

We have studied the electronic characteristics of covalently functionalized graphene by nitrophenol groups using first-principles density-functional theory calculations. The nitrophenyl functionalization leads to a band gap opening in graphene and transition from a semi-metallic to semiconducting state. The induced gap is shown to be attributed to the modification of the ?-conjugation that depends on the configuration for a pair of monovalent adsorption. A detailed analysis reveals that this intriguing magnetism modulation by strain stems from the redistribution of spin-polarized electrons induced by local lattice distortions. A detailed analysis suggests a sensitive and effective way to tailor properties of graphene for future applications in nanoscale devices. The quest for low-dimensional boron structures has been motivated by the potential applications of light-weight materials. Recently, a semi-metallic two-dimensional boron allotrope was predicted via ab initio evolutionary structure search, which is markedly lower in energy than the planar structures composed of triangular motifs and hexagonal holes. The emergence of a Dirac cone in the band structure demonstrates an intriguing perspective for quasiplanar counterpart of graphene. We studied the corresponding single walled boron nanotubes derived from the quasiplanar boron structure. In particular, our results are identified to have a Dirac cone, as well. The buckling and coupling between the two sublattices not only enhance the stability, but also are key factors to the emergence of the Dirac cone.

Graphene is a two-dimensional system consisting of a single planar layer of carbon atoms with hexagonal arrangement. Various approaches have been proposed to control its physical and electronic properties. When appropriately cut, rolled, and bonded, graphene generates single-walled carbon nanotubes of varying diameters. Graphite intercalation compounds are materials formed by inserting molecular layers of compounds between stacked sheets of graphene. We have studied the physical and electronic responses of two graphene layers intercalated with FeCl3 and of metallic, semi-metallic and semiconducting nanotubes when normally biased using electric fields of various magnitudes. By means of first-principles density functional calculations, our results indicate that the band structures of the aforementioned graphene structures are modified upon application of a bias voltage. In the case of nanotubes, electric biasing allows tuning of the band gap leading to a transition from semiconducting to metallic state, or vice versa. In the case of the FeCl3 intercalant compounds, electric biasing results in shifting of the Dirac point.

Theoretical study of energy levels, oscillator strengths, transition probabilities, and lifetimes of Si III lines has been reported in this thesis. These atomic parameters are required for the interpretation of emission and absorption lines of Si III and for the modeling of astrophysical plasmas including Galactic High Velocity Clouds (HVCs), the Sun, and white dwarf stars. We used Hartree-Fock (HF) and Multiconfiguration Hartree-Fock (MCHF) methods in our calculations. We have considered 58 levels of the 3s2, 3s3p, 3p2, 3s3d, 3s4s, 3s4p, 3s4d, 3s4f, 3s5s, 3s5p, 3s5d, 3s6s, and 3s5f configurations. The relativistic corrections are included in Breit-Pauli approximation by using one-body Darwin, mass correction, spin-orbit operators, and two-body spin-other-orbit and spin-spin operators. The results have been compared with previous theoretical results and available experimental data, and generally a good agreement is found. KEY TERMS: Si III, Breit-Pauli, Atomic Structure, Si, Hartree-Fock, MCHF, Atomic, Molecular and Optical Physics, Physics

We present an investigation of quantum confinement effects in nanowire heterostructures through the use of an effective-mass model with a band-offset induced potential barrier. The characteristic size of microelectronics is rapidly approaching the nanometer scale and because of this, nanostructure based devices in the field of nanomaterial research is continually being emphasized. The quantum confinement effect exhibited by the nanowire is the most interesting in one-dimensional nanostructures. Potential applications for the nanowire include its use in the fabrication of high performance devices such as the p n junction diode, the p-channel or n-channel coaxial gated field effect transistor, and the complimentary field effect transistors, to name a few. In the fabrication of such devices, a doping process is used in order to supply free carriers. This process involves introducing doped impurities which unfortunately causes difficulties. These difficulties are characterized by a marked decrease in the mobility of the aforementioned carriers and include the scattering of the free carriers. To remedy these problems a novel doping mechanism has been proposed. It involves the use of a radial heterojunction in a core-shell nanowire where it has been suggested that one can dope impurities in the shell and inject free carriers to the core or vice versa. This separation of free carriers reduces their scattering rate and improves their mobility, both preferred properties for high-speed devices. A better understanding of the heterojunction under strong cylindrical confinement is important to guide the future fabrication of nanowire-based high-speed devices. In order to achieve this, the question as to whether the band offset evolves with the size of the nanowire needs to be addressed. The inquiry into the relationship between band offset evolution and nanowire size led us to employ an effective-mass model with a band-offset induced potential barrier to study the band structure

The energy levels, lifetimes, oscillator strengths, and transition probabilities of N II lines have been reported in this thesis. We have used the Hartree-Fock (HF) and Multiconfiguration Hartree-Fock (MCHF) methods in our calculations. The relativistic operators mass correction, one-body Darwin term, spin-orbit interaction, and spin-other-orbit have been included in the Breit-Pauli Hamiltonian in our calculations of atomic parameters of singly-ionized nitrogen. We considered 70 levels of the 2s2 2p2, 2s2 2p3, 2s2 2p 3p, 2s2 2p 3s, 2s2 2p 4p, 2s2 2p 3d, 2s2 2p 4s, and 2s2 2p 4d configurations of N II. Our results have been compared with other available calculations and measurements, and generally a good agreement is found. KEY TERMS: Energy Level, Lifetimes, Oscillator strengths, Transition probabilities, N II, Physics

In this thesis we discuss the molecular dynamics simulation study of two conjugated polymers wrapping around single-walled carbon nanotubes (SWNTs). One is the widely used PmPV and the other is a PPE-PPV co-polymer. The molecular dynamics study shows that both polymers can wrap helically around SWNTs. The binding energy for each wrapped species is extracted, and is found to be sensitive to the contact area between the polymers benzene ring and the underlying parallel carbon nanotube. Our results indicate that the larger the diameters of SWNTs, the greater the binding energy due to the reduction in the misalignment and the increase of ?- ? interactions. This provides useful information for experimental studies.

Ultraviolet photoemission spectroscopy measurements reveal that there is notable variation of the electron density of states in valence bands near the Fermi level. Evolution of the electronic structure of fluorinated graphene as a function ofthe applied electric bias is investigated. The experimental results demonstrate that the tailoring of electronic band structure correlates with the interlayer coupling tuned by the applied bias. The change in the work function of fluorinated graphene demonstrates the ability of fluorination to modify electron emissions characteristics of graphene.