EFFECTS OF APERIODICITY AND FRUSTRATION ON THE MAGNETIC PROPERTIES OF ARTIFICIAL QUASICRYSTALS

Quasicrystals have been shown to exhibit physical properties that are dramatically different from their periodic counterparts. A limited number of magnetic quasicrystals have been fabricated and measured, and they do not exhibit long-range magnetic order, which is in direct conflict with simulations that indicate such a state should be accessible. This dissertation adopts a metamaterials approach in which artificial quasicrystals are fabricated and studied with the specific goal of identifying how aperiodicity affects magnetic long-range order. Electron beam lithography techniques were used to pattern magnetic thin films into two types of aperiodic tilings, the Penrose P2, and Ammann-Beenker tilings. SQUID magnetometer measurements were performed on sample artificial quasicrystals, and their low-temperature, ground-state magnetization textures were directly imaged using X-ray photoemmission electron microscopy (PEEM) and scanning electron microscopy with polarization analysis (SEMPA) techniques. Monte Carlo simulations of the ground state configurations for Penrose P2 and Ammann-Beenker tilings indicate the emergence of complex ordered sublattices that have not been previously observed in periodic systems. Magnetic imaging of artificial quasicrystals show regions of long-range order in an imperfectly equilibrated state. Defects are found between superdomain walls and between smaller, highly correlated vertex clusters. These results bear on the current lack of evidence for long-range magnetic order in three-dimensional atomic quasicrystals

The Moralization of Nietzsche

The inflammatory and elitist language Nietzsche uses in Beyond Good and Evil to describe the relationship between the ruling class and the underclass is often read as hyperbolic, and attempts are often made in the secondary literature to spare him the appearance of advocating gratuitous exploitation. This thesis challenges the assumption that Nietzsche is speaking hyperbolically in the passages in question. It argues in fact that the descriptive project Nietzsche undertakes in Beyond Good and Evil requires the prima facie radical exploitation it puts forward. The central aim of the thesis is to situate his description of human exploitation within the broader framework of a perfectionistic account the conditions of human advancement

Azomethine derivatives of some metals and metalloids

This thesis describes the preparation of some methyleneamino derivatives of beryllium, zinc, gallium and silicon. The structural, implications of their infra-red spectra and nuclear magnetic resonance spectra are discussed. As a background to the work, the characteristics of such compounds are discussed in the Introduction, and in greater detail in each chapter. Di-t-butylmethyleneaminolithium reacts with beryllium chloride giving dimeric di-t-butylmethyleneaminoberyllium chloride, (Bu(^t)(_2)C:NBeCl)(_2), and the lithium beryllates Li(_n)Be(N:CBu(^t)(_2))(_2+n) (n = 1,2). Bis(di-t-butylmethyl-eneamino)beryllium, [(Bu(^t)(_2)C:N)(_2)Be](_2) was inaccessible by this route but was prepared by reacting di-t-butylmethyleneamine with di-isobutylberyllium (2:1). The crystal structure of this compound shows that the terminal CNBe unit is nearly linear and that the Be-N bond is relatively short, appropriate for N →Be (p → p) π-bonding. The structure determination supports the postulate that a high azomethine stretching frequency, v(C=N) is indicative of a linear CNBe unit and Be-N multiple bonding. Attempts to prepare adducts with trimethylamine and tetramethylethylene-diamine were unsuccessful. Reaction between methyleneamines and dialkylberylliums afford the derivatives (R(^2)C:NBeR’)(_2) (R = Bu(^2), Ph; R' = Bu(^i) and R = Ph; R' = Bu(^t)). A new monomeric compound, di-t-butylmethyleneamino-bis(trimethylsilyl)-aminoberyllium, Bu(^t)(_2)C:NBeN(SiMe(_3))(_2) was prepared and characterised. Reactions of zinc chloride with one or two moles of di-t-butylmethyl-eneaminolithium give dimeric iminozinc compounds, (Bu(^t)(_2)C:NZnCl)(_2) and [(Bu(^t)(_2)C:N)(_2)Zn](_2). A high azomethine stretching frequency in the latter compound is attributed to significant pπpπ interaction between zinc and nitrogen. Dimethylzinc reacts with one or two moles of di-t-butylmethyl-eneamine giving [(Bu(^t)(_2)CN)(_n)ZnMe(_2-n)])_2) (n = 1,2). Reaction between di-t-butylmethyleneaminolithium and gallium trichloride affords the compounds Li(_n)Ga(N: CBu(^t)(_2))(_3+n) (n = 0,1,2). Bis(di-t-butylmethyleneamino)gallium chloride could not be isolated, presumably through disproportionation to the mono- and tris-derivatives. A high azomethine stretching frequency, v(C=N), for (Bu(^t)(_2)C:N)(_3)Ga, is taken as evidence for a linear C=N-Ga skeleton with appreciable N=Ga π-bonding. The phenyl analogue (Ph(_2)C:N)(_3)Ga was prepared by a similar method. Equimolar proportions of diphenylmethyleneaminolithium and chlorosilanes Me(_n)SiCl(_4-n), (n = 0,1,2) afford the diphenylmethy1eneamino-silanes (Ph(_2)C:N)(_2)-SiM(_n)Cl(_3-n), apparently through disproportionation of the mono-substituted compounds Ph(_2)C:NSiMe(_n)Cl(_3-n), which could only be isolated when n = 2. The spectra of these compounds show that these may have bent C:NSi skeletons. Preliminary investigations into transition metal systems (R(_2)C:N)(_3)M (M = Fe; R = Bu(^t),Ph and M = Cr; R = Bu(^t)) are discussed in an appendix

Globular Structure of a Human Immunodeficiency Virus-1 Protease (1DIFA dimer) in an Effective Solvent Medium by a Monte Carlo Simulation

A coarse-grained model is used to study the structure and dynamics of a human immunodeficiency virus-1 protease (1DIFA dimer) consisting of 198 residues in an effective solvent medium on a cubic lattice by Monte Carlo simulations for a range of interaction strengths. Energy and mobility profiles of residues are found to depend on the interaction strength and exhibit remarkable segmental symmetries in two monomers. Lowest energy residues such as Arg(41) and Arg(140) (most electrostatic and polar) are not the least mobile; despite the higher energy, the hydrophobic residues (Ile, Leu, and Val) are least mobile and form the core by pinning down the local segments for the globular structure. Variations in the gyration radius (R(g)) and energy (E(c)) of the protein show nonmonotonic dependence on the interaction strength with the smallest R(g) around the largest value of E(c). Pinning of the conformations by the hydrophobic residues at high interaction strength seems to provide seed for the protein chain to collapse

The Link between Scrambling Numbers and Derangements

The group equation abcdef = dabecf can be reduced to the equation xcde = dxec. In general, we are interested in how many variables are needed to represent group equations in which the right side is a permutation of the variables on the left side. Scrambling numbers capture this information about a permutation. In this paper we present several facts about scrambling numbers, and expose a striking relationship between permutations that cannot be reduced and derangements

Random Coil to Globular Thermal Response of a Protein (H3.1) with Three Knowledge-Based Coarse-Grained Potentials

The effect of temperature on the conformation of a histone (H3.1) is studied by a coarse-grained Monte Carlo simulation based on three knowledge-based contact potentials (MJ, BT, BFKV). Despite unique energy and mobility profiles of its residues, the histone H3.1 undergoes a systematic (possibly continuous) structural transition from a random coil to a globular conformation on reducing the temperature. The range over which such a systematic response in variation of the radius of gyration (Rg) with the temperature (T) occurs, however, depends on the potential, i.e. ΔTMJ ≈ 0.013–0.020, ΔTBT ≈ 0.018–0.026, and ΔTBFKV ≈ 0.006–0.013 (in reduced unit). Unlike MJ and BT potentials, results from the BFKV potential show an anomaly where the magnitude of Rg decreases on raising the temperature in a range ΔTA ≈ 0.015–0.018 before reaching its steady-state random coil configuration. Scaling of the structure factor, S(q) ∝ q−1/ν, with the wave vector, q = 2π/λ, and the wavelength, λ, reveals a systematic change in the effective dimension (De∼1/ν) of the histone with all potentials (MJ, BT, BFKV): De∼3 in the globular structure with De∼2 for the random coil. Reproducibility of the general yet unique (monotonic) structural transition of the protein H3.1 with the temperature (in contrast to non-monotonic structural response of a similar but different protein H2AX) with three interaction sets shows that the knowledge-based contact potential is viable tool to investigate structural response of proteins. Caution should be exercise with the quantitative comparisons due to differences in transition regimes with these interactions

Conformational Response to Solvent Interaction and Temperature of a Protein (Histone h3.1) by a Multi-Grained Monte Carlo Simulation

Interaction with the solvent plays a critical role in modulating the structure and dynamics of a protein. Because of the heterogeneity of the interaction strength, it is difficult to identify multi-scale structural response. Using a coarse-grained Monte Carlo approach, we study the structure and dynamics of a protein (H3.1) in effective solvent media. The structural response is examined as a function of the solvent-residue interaction strength (based on hydropathy index) in a range of temperatures (spanning low to high) involving a knowledge-based (Miyazawa-Jernigan(MJ)) residue-residue interaction. The protein relaxes rapidly from an initial random configuration into a quasi-static structure at low temperatures while it continues to diffuse at high temperatures with fluctuating conformation. The radius of gyration (Rg) of the protein responds non-monotonically to solvent interaction, i.e., on increasing the residue-solvent interaction strength (fs), the increase in Rg (fs≤fsc) is followed by decay (fs≥fsc) with a maximum at a characteristic value (fsc) of the interaction. Raising the temperature leads to wider spread of the distribution of the radius of gyration with higher magnitude of fsc. The effect of solvent on the multi-scale (λ: residue to Rg) structures of the protein is examined by analyzing the structure factor (S(q),|q| = 2π/λ is the wave vector of wavelength, λ) in detail. Random-coil to globular transition with temperature of unsolvated protein (H3.1) is dramatically altered by the solvent at low temperature while a systematic change in structure and scale is observed on increasing the temperature. The interaction energy profile of the residues is not sufficient to predict its mobility in the solvent. Fine-grain representation of protein with two-node and three-node residue enhances the structural resolution; results of the fine-grained simulations are consistent with the finding described above of the coarse-grained description with one-node residue

Perbandingan Kualitas Layanan Berdasarkan Kategori Restoran : Studi Kasus Di Badung Bali

In service industry, service quality is used as one factor in competition. Culinaryindustry, such as restaurant, bar, cafe, or eatery booth are one dynamic sector intourism world. As a tourist destination either domestic or International, Bali createsa competitive business environment either local or International as well.American restaurant in average shows a higher score in service quality comparewith others. But Indonesian restaurant gives a higher scores in empathy dimension inservice quality. Customer is expecting a good services, especially in culinary industryin sustaining their businesses. The company should look carefully into aspects ofservice quality, hence they can be a winner in the competitive industry

Preferential Binding Effects On Protein Structure and Dynamics Revealed by Coarse-Grained Monte Carlo Simulation

The effect of preferential binding of solute molecules within an aqueous solution on the structure and dynamics of the histone H3.1 protein is examined by a coarse-grained Monte Carlo simulation. The knowledge-based residue-residue and hydropathy-index-based residue-solvent interactions are used as input to analyze a number of local and global physical quantities as a function of the residue-solvent interaction strength (f). Results from simulations that treat the aqueous solution as a homogeneous effective solvent medium are compared to when positional fluctuations of the solute molecules are explicitly considered. While the radius of gyration (Rg) of the protein exhibits a non-monotonic dependence on solvent interaction over a wide range of f within an effective medium, an abrupt collapse in Rg occurs in a narrow range of f when solute molecules rapidly bind to a preferential set of sites on the protein. The structure factor S(q) of the protein with wave vector (q) becomes oscillatory in the collapsed state, which reflects segmental correlations caused by spatial fluctuations in solute-protein binding. Spatial fluctuations in solute binding also modify the effective dimension (D) of the protein in fibrous (D ∼ 1.3), random-coil (D ∼ 1.75), and globular (D ∼ 3) conformational ensembles as the interaction strength increases, which differ from an effective medium with respect to the magnitude of D and the length scale

Biofunctionalization and Immobilization of a Membrane via Peptide Binding (CR3-1, S2) by a Monte Carlo Simulation

A coarse-grained computer simulation model is used to study the immobilization of a dynamic tethered membrane (representation of a clay platelet) in a matrix of mobile peptide chains CR3-1:(1)Trp-(2)Pro-(3)Ser-(4)Ser-(5)Tyr-(6)Leu-(7)Ser-(8)Pro-(9)Ile-(10)Pro-(11)Tyr-(12)Ser and S2:(1)His-(2)Gly-(3)Ile-(4)Asn-(5)Thr-(6)Thr-(7)Lys-(8)Pro-(9)Phe-(10)Lys-(11)Ser-(12)Val on a cubic lattice. Each residue interacts with the membrane nodes with appropriate interaction and executes their stochastic motion with the Metropolis algorithm. Density profiles, binding energy of each residue, mobility, and targeted structural profile are analyzed as a function of peptide concentration. We find that the binding of peptides S2 is anchored by lysine residues ((7)Lys,(10)Lys) while peptides CR3-1 do not bind to membrane. The membrane slows down as peptides (S2) continues to bind leading to its eventual pinning. How fast the immobilization of the membrane occurs depends on peptide concentration. Binding of peptide (S2) modulates the morphology of the membrane. The immobilization of membrane occurs faster if peptides (S2) are replaced by the homopolymer of lysine ([Lys](12) of the same molecular weight), the strongest binding residue. The surface of membrane can be patterned with somewhat reduced roughness with the homopolymer of lysine than that with peptide (S2). (C) 2010 American Institute of Physics. [doi:10.1063/1.3484241