Noninteracting Parts Research Articles

Polymer Wrapping onto Nanoparticles Induces the Formation of Hybrid Colloids

Polymers stabilize the nanoparticles onto which they wrap, avoiding coagulation and undesired phase separation processes. Wrapping gives rise to hybrid colloids, and is useful in bio-intended applications. In non-covalent interaction modes, polymers physically adsorb onto the nanoparticles’ surface, NPs, and some of their portions protrude outside. Both their non-interacting parts and the free polymers are in contact with the solvent, and/or are dispersed in it. Wrapping/protruding ratios were forecast with a simple statistical thermodynamic model, and the related energy calculated. The wrapping efficiency is controlled by different contributions, which stabilize polymer/NP adducts. The most relevant ones are ascribed to the NP-polymer, polymer–polymer, and polymer–solvent interaction modes; the related energies are quite different from each other. Changes in the degrees of freedom for surface-bound polymer portions control the stability of adducts they form with the NPs. The links between wrapped, free, and protruding states also account for depletion, and control the system’s properties when the surface adsorption of hosts is undesired. Calculations based on the proposed approach were applied to PEO wrapping onto SiO2, silica, and nanoparticles. The interaction energy, W, and the changes in osmotic pressure associated with PEO binding onto the NPs have been evaluated according to the proposed model.

Composite wing vibration coupling control

The paper discusses the possibility to control coupled bending-twisting vibrations of composite wing by means of the monoclinic structures in the reinforcement of the plating. Decomposing the potential straining energy and kinetic energy of natural vibration modes into interacting and non-interacting parts, it became possible to introduce the two coefficients that integrally consider the effect of geometry and reinforcement structure upon the dynamic response parameters of the wing. The first of these coefficients describes the elastic coupling of the natural vibration modes, the second coefficient describes the inertial one. The paper describes the numerical studies showing how the orientation of considerably anisotropic CRP layers in the plating affects natural frequencies, loss factors, coefficients of elastic and inertial coupling for several lower tones of natural bending-twisting vibrations of the wing. Besides, for each vibration mode, partial values of the above mentioned dynamic response parameters were determined by means of the relationships for orthotropic structures where instead of “free” shearing modulus in the reinforcement plant, “pure” shearing modulus is used. Joint analysis of the obtained results has shown that each pair of bendingtwisting vibration modes has its orientation angle ranges of the reinforcing layers where the inertial coupling caused by asymmetry of the cross-section profile with respect to the main axes of inertia decreases, down to the complete extinction, due to the generation of the elastic coupling in the plating material. These ranges are characterized by the two main features: 1) the difference in the natural frequencies of the investigated pair of bendingtwisting vibration modes is the minimum and 2) natural frequencies of bending-twisting vibrations belong to a stretch restricted by corresponding partial natural frequencies of the investigated pair of vibration modes. This result is of practical importance because it enables approximate analysis of real composite wings with complex geometry in the existing commercial software packages.

Spectral Properties of Dissipation

Abstract The novel concept of spectral diffusivity is introduced to analyze the dissipative properties of continua. The dissipative components of a linear system of evolution equations are separated into noninteracting parts. This separation is similar to mode analysis in wave propagation. The new modal quantities characterize dissipation and are best interpreted as effective diffusivities, or, in case of the heat conduction, as effective heat conductivities of the material.

A Dirac-Fermions functional for Coulomb interaction on arbitrary (fractional) dimension: Energy and pressure

Dirac-Fermions with interaction are considered directly by means of a simple Density Functional being the main concern the background energy as a function of the spatial dimension (fractional or not). The background energy grows as the dimension continuously rises. Comparison between the interacting and the non-interacting parts suggests that, around dimension two, both contributions are important. On the contrary, for dimensions other than two, interacting effects seem partially eclipsed (screening). Further, thermodynamics aspects related to dimension uncertainties are considered. Additionally, a massive branch appears.

Vibrational Partition Function for the Multitemperature Theories of High-Temperature Flows of Gases and Plasmas.

The vibrational partition function is calculated using the classical method of integration over the whole phase space. The calculations were done for the ground electronic state of a carbon monoxide molecule. The main focus is on temperature in the range 5000-20 000 K, which is common in hypersonic flows of gases and plasmas. The method presented here, because of the exclusion of the noninteracting part of canonical partition function according to the ideas of T.L. Hill, is applicable at temperatures of tens of thousands of Kelvins, where the standard expression for the vibrational partition function fails. At lower temperatures (here 1000-6000 K), the correct quantum results can be obtained with the help of Wigner-Kirkwood expansion. The influence of vibrations on the rotational partition function by bond-length elongation is examined, and the results are compared with the exact ro-vibrational partition function.

Effect of the soft layer thickness on magnetization reversal process of exchange-spring nanomagnet patterns

A systematic study of the magnetization reversal behavior in the regular arrangement of L10-FePt based exchange-spring nanomagnets with different thicknesses of the Co soft magnetic layer is presented. The magnetic property of the hard magnet is compared to two tuned exchange-spring magnets: its systems of 20 nm L10-FePt/3 nm, and 7 nm Co. In particular, we focus on the switching field distribution. The exchange coupling showed narrower SFD, in spite of the decoupled part switches earlier. The magnetization switching mechanism of exchange-spring nanomagnets patterns has been revealed with a first-order reversal curves technique and the switching field distribution. Further, the microscopic results using magnetic force microscopy show that the spin rotation of the non-interacting part in the thicker soft layered exchange-spring magnet. The part influences the magnetization reversal process. According to the experimental results, exchange coupling strength can be tuned by the thickness of the soft magnetic layer.

Characterising glass transition temperatures and glass dynamics in mesoporous silica-based amorphous drugs.

In this study the glass transition temperatures (Tgα and Tgβ) in mesoporous silica-based amorphous drugs were characterized. For this purpose, mesoporous silica Parteck SLC (MPS) was loaded with the drugs ibuprofen and carvedilol, either below, at, or above the monomolecular drug loading capacities, i.e. the concentration at which the entire MPS surface is covered with a monolayer of drug molecules. The resulting amorphous forms were analysed using X-ray powder diffraction and the thermal behaviour was characterised with differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The drug monolayer did not contribute to the thermal signal in DSC. Using DMA however, it could be shown that the monolayer indeed exhibited a very weak Tgα, and that the temperature range of this transition did not differ from that of the quench cooled amorphous drugs. Theoretical ab initio molecular dynamics simulations revealed that the nature of hydrogen bonding geometry of the functional groups interacting with the MPS surface were similar to that of the respective crystalline drugs, which results in restricted molecular motions for those functional groups. On the other hand, the non-interacting parts of the molecules exhibited molecular motions similar to what is observed in pure amorphous drugs. As a result of the interactions of the monolayer with the MPS surface, the monomolecular drug layer did not reveal a Tgβ. However, a Tgβ was found at any drug-MPS ratios above the monomolecular drug loading capacity as a result of the excess drug which forms a "true" amorphous phase. Overall, this study demonstrated that drug molecules forming an amorphous monolayer on the surfaces of a mesoporous silica particle, even though they are restricted in their mobility, exhibit a Tgα, but lack a Tgβ, whereas any excess drug confined in the MPS pores showed similar properties as the pure amorphous drug. These findings will help to increase the overall understanding of drug loaded MS systems, including their physical stability as well as release properties.

Interacting hadron resonance gas model in the K -matrix formalism

An extension of Hadron Resonance Gas (HRG) model is constructed to include interactions using relativistic virial expansion of partition function. The non-interacting part of the expansion contains all the stable baryons and mesons and the interacting part contains all the higher mass resonances which decay into two stable hadrons. The virial coefficients are related to the phase shifts which are calculated using K-matrix formalism in the present work. We have calculated various thermodynamics quantities like pressure, energy density, and entropy density of the system. A comparison of thermodynamic quantities with non interacting HRG model, calculated using the same number of hadrons, shows that the results of above formalism are larger. A good agreement between equation of state calculated in K-matrix formalism and lattice QCD simulations is observed. Specifically the lattice QCD calculated interaction measure is well described in our formalism. We have also calculated second order fluctuations and correlations of conserved charges in K-matrix formalism. We observe a good agreement of second order fluctuations and baryon-strangeness correlation with lattice data below the cross-over temperature.

Revised Thomas-Fermi approximation for singular potentials

Approximations for the many-fermion free-energy density functional that include the Thomas-Fermi (TF) form for the noninteracting part lead to singular densities for singular external potentials (e.g., attractive Coulomb). This limitation of the TF approximation is addressed here by a formal map of the exact Euler equation for the density onto an equivalent TF form characterized by a modified Kohn-Sham potential. It is shown to be a ``regularized'' version of the Kohn-Sham potential, tempered by convolution with a finite-temperature response function. The resulting density is nonsingular, with the equilibrium properties obtained from the total free-energy functional evaluated at this density. This new representation is formally exact. Approximate expressions for the regularized potential are given to leading order in a nonlocality parameter, and the limiting behavior at high and low temperatures is described. The noninteracting part of the free energy in this approximation is the usual Thomas-Fermi functional. These results generalize and extend to finite temperatures the ground-state regularization by R. G. Parr and S. Ghosh [Proc. Natl. Acad. Sci. U.S.A. 83, 3577 (1986)] and by L. R. Pratt, G. G. Hoffman, and R. A. Harris [J. Chem. Phys. 88, 1818 (1988)] and formally systematize the finite-temperature regularization given by the latter authors.

Interactivity and memory: Information processing of interactive versus non-interactive content

Existing research on the effects of interactivity tends to treat it as a global characteristic of the interface. However, not all content on an interface is endowed with interactive features. Therefore, it is important to explore how interactivity affects the cognitive processing of those particular content that is presented with interactive features and the surrounding content without these features. With this objective, a between-subjects experiment was conducted to understand how levels of interactivity affect information processing among users of an e-commerce website. The major findings of the study are: 1) Higher interactivity enhances recognition as well as recall memory of interactive content, but diminishes recognition and recall memory of non-interactive content; 2) Individuals spend the least amount of time on the interface with high interactivity, while most of this time is spent on interactive part rather than non-interactive part of the interface; 3) A moderate level of interactivity attracts most user attention to product information. The findings about interactivity’s effect have implications for cue-summation theory and limited capacity theory. The experiment’s results also hold practical implications for e-tailers.

Spin dependent transport through triangular graphene quantum dot in the presence of Rashba type spin–orbit coupling

Electronic, magnetic and transport properties of a triangle graphene quantum dot have been studied in the presence of Rashba type spin–orbit coupling. The non-interacting part is written in the tight-binding model, and we use the Kene–Mele–Hubbard (KMH) Hamiltonian to describe the electron–electron and the Rashba spin–orbit interaction. While the Hubbard term split the spin up and down states, the Rashba term mixed these states. The competition between these two effects produces an interesting situation in a nano-device. Our results indicate that the magnetization of zigzag edge and spin coherence are decreased due to the Rashba spin–orbit interaction in the triangle graphene quantum dot. It is shown that the reduction of spin coherence is non-negligible even in the case of weak Rashba spin–orbit interaction.

Efficacy and safety of perindopril arginine + amlodipine in hypertension

Electronic, magnetic and transport properties of a triangle graphene quantum dot have been studied in the presence of Rashba type spin–orbit coupling. The non-interacting part is written in the tight-binding model, and we use the Kene–Mele–Hubbard (KMH) Hamiltonian to describe the electron–electron and the Rashba spin–orbit interaction. While the Hubbard term split the spin up and down states, the Rashba term mixed these states. The competition between these two effects produces an interesting situation in a nano-device. Our results indicate that the magnetization of zigzag edge and spin coherence are decreased due to the Rashba spin–orbit interaction in the triangle graphene quantum dot. It is shown that the reduction of spin coherence is non-negligible even in the case of weak Rashba spin–orbit interaction.

Statistical Properties of Molecular Clumps in the Galactic Center 50 km s-1 Molecular Cloud

Abstract We present the statistical properties of molecular clumps in the Galactic center 50 km s$ ^{-1}$ molecular cloud (GCM-0.02-0.07) based on observations of the CS $ J$$ =$ 1–0 emission line with the Nobeyama Millimeter Array. In the cloud, 37 molecular clumps with local thermodynamic equilibrium (LTE) masses of 2 $ \times$ 10$ ^{2}$ –6 $ \times$ 10$ ^{3}\ M_{\odot}$ were identified by using the clumpfind algorithm. The velocity widths of the molecular clumps are about five-fold those of Galactic disk molecular clouds with the same radius. The virial-theorem masses are three-fold the LTE masses. The mass and size spectra can be described by power laws of $ dN/dM$$ \propto$$ M^{-2.6\pm0.1}$ ($ M$$ \gtrsim$ 900 $ M_{\odot}$ ) and $ dN/dR$$ \propto$$ R^{-5.9\pm0.3}$ ($ R$$ \gtrsim$ 0.35 pc), respectively. The statistical properties of the region interacting with the Sgr A East shell and those of the non-interacting part of the cloud are significantly different. The interaction probably makes the mass function steeper, from $ dN/dM$$ \propto$$ M^{-2.0\pm0.1}$ in the non-interacting part to $ dN/dM$$ \propto$$ M^{-4.0\pm0.2}$ in the interacting region. On the other hand, the interaction presumably truncates the size spectrum on the larger side of $ R$$ \sim$ 0.4 pc.

Super-group field cosmology

In this paper, we construct a model for group field cosmology. The classical equations of motion for the non-interactive part of this model generate the Hamiltonian constraint of loop quantum gravity for a homogeneous isotropic universe filled with a scalar matter field. The interactions represent topology changing processes that occur due to joining and splitting of universes. These universes in the multiverse are assumed to obey both bosonic and fermionic statistics, and so a supersymmetric multiverse is constructed using superspace formalism. We also introduce gauge symmetry in this model. The supersymmetry and gauge symmetry are introduced at the level of third quantized fields, and not the second quantized ones. This is the first time that supersymmetry has been discussed at the level of third quantized fields.

Fractional topological phase in one-dimensional flat bands with nontrivial topology

We show the existence of the fractional topological phase (FTP) in a one-dimensional interacting fermion model using exact diagonalization, in which the non-interacting part has flatbands with nontrivial topology. In the presence of the nearest-neighbouring interaction $V_{1}$, the FTP at filling factor $\nu =1/3$ appears. It is characterized by the three-fold degeneracy and the quantized total Berry phase of the ground-states. The FTP is destroyed by a next-nearest-neighbouring interaction $V_{2}$ and the phase diagrams in the $(V_{1},V_{2})$ plane is determined. We also present a physical picture of the phase and discuss its existence in the nearly flatband. Within the picture, we argue that the FTP at other filling factors can be generated by introducing proper interactions. The present study contributes to a systematic understanding of the FTPs and can be realized in cold-atom experiments.

Quantum continuum mechanics made simple

In this paper we further explore and develop the quantum continuum mechanics (QCM) of Tao et al. [Phys. Rev. Lett. 103, 086401 (2009)] with the aim of making it simpler to use in practice. Our simplifications relate to the non-interacting part of the QCM equations, and primarily refer to practical implementations in which the groundstate stress tensor is approximated by its Kohn-Sham (KS) version. We use the simplified approach to directly prove the exactness of QCM for one-electron systems via an orthonormal formulation. This proof sheds light on certain physical considerations contained in the QCM theory and their implication on QCM-based approximations. The one-electron proof then motivates an approximation to the QCM (exact under certain conditions) expanded on the wavefunctions of the KS equations. Particular attention is paid to the relationships between transitions from occupied to unoccupied KS orbitals and their approximations under the QCM. We also demonstrate the simplified QCM semianalytically on an example system.

Fractional quantum Hall effect in the absence of Landau levels

It is well known that the topological phenomena with fractional excitations, the fractional quantum Hall effect, will emerge when electrons move in Landau levels. Here we show the theoretical discovery of the fractional quantum Hall effect in the absence of Landau levels in an interacting fermion model. The non-interacting part of our Hamiltonian is the recently proposed topologically non-trivial flat-band model on a checkerboard lattice. In the presence of nearest-neighbouring repulsion, we find that at 1/3 filling, the Fermi-liquid state is unstable towards the fractional quantum Hall effect. At 1/5 filling, however, a next-nearest-neighbouring repulsion is needed for the occurrence of the 1/5 fractional quantum Hall effect when nearest-neighbouring repulsion is not too strong. We demonstrate the characteristic features of these novel states and determine the corresponding phase diagram.

Virial theorem in the Kohn–Sham density-functional theory formalism: Accurate calculation of the atomic quantum theory of atoms in molecules energies

A new approach for computing the atom-in-molecule [quantum theory of atoms in molecule (QTAIM)] energies in Kohn-Sham density-functional theory is presented and tested by computing QTAIM energies for a set of representative molecules. In the new approach, the contribution for the correlation-kinetic energy (T(c)) is computed using the density-functional theory virial relation. Based on our calculations, it is shown that the conventional approach where atomic energies are computed using only the noninteracting part of the kinetic energy might be in error by hundreds of kJ/mol.

Spectral and entropic characterizations of Wigner functions: Applications to model vibrational systems

The Wigner function for the pure quantum states is used as an integral kernel of the non-Hermitian operator K, to which the standard singular value decomposition (SVD) is applied. It provides a set of the squared singular values treated as probabilities of the individual phase-space processes, the latter being described by eigenfunctions of KK(+) (for coordinate variables) and K(+)K (for momentum variables). Such a SVD representation is employed to obviate the well-known difficulties in the definition of the phase-space entropy measures in terms of the Wigner function that usually allows negative values. In particular, the new measures of nonclassicality are constructed in the form that automatically satisfies additivity for systems composed of noninteracting parts. Furthermore, the emphasis is given on the geometrical interpretation of the full entropy measure as the effective phase-space volume in the Wigner picture of quantum mechanics. The approach is exemplified by considering some generic vibrational systems. Specifically, for eigenstates of the harmonic oscillator and a superposition of coherent states, the singular value spectrum is evaluated analytically. Numerical computations are given for the nonlinear problems (the Morse and double well oscillators, and the Henon-Heiles system). We also discuss the difficulties in implementation of a similar technique for electronic problems.

A fast method of large-scale serial semiempirical calculations of docking complexes

A brief survey of the state of the art in methods of calculations of protein—ligand interaction energies in docking complexes is presented. A new computational technique is proposed that allows one to fundamentally improve the performance of large-scale serial calculations of docking complexes using the AM1/PM3 semiempirical methods. The technique explicitly allows for a specific feature of docking problems, viz., the need for calculating numerous ligand complexes with a specified protein whose noninteracting part remains “frozen” during computations. The interaction energies calculated using the new method differ only slightly from the results of complete AM1 calculations and the performance attained is high enough to solve practical drug design problems.