Magic Numbers in Boson 4He Clusters: The Auger Evaporation Mechanism

The absence of magic numbers in bosonic 4He clusters predicted by all theories since 1984 has been challenged by high-resolution matter-wave diffraction experiments. The observed magic numbers were explained in terms of enhanced growth rates of specific cluster sizes for which an additional excitation level calculated by diffusion Monte Carlo is stabilized. The present theoretical study provides an alternative explanation based on a simple independent particle model of the He clusters. Collisions between cluster atoms in excited states within the cluster lead to selective evaporation via an Auger process. The calculated magic numbers as well as the shape of the number distributions are in quite reasonable agreement with the experiments.

Anisotropic optical response of gold-silver alloys

Gold and silver alloys enable novel opportunities for engineering materials with distinct optical responses. Here we investigate the optical properties of gold and silver (Ag x Au 1−x) structures using First-Principle Density Functional Theory (DFT) for gold concentrations varying from 0% up to 100% with steps of 25%. Results of the optical permittivity are analyzed with the independent particle approximation and compared with previously reported theoretical and experimental works. The pure systems and the ones with unbalanced concentrations exhibit isotropic optical responses. The Ag 0.50 Au 0.50 shows an anisotropic response among the y-direction and the xz-direction, mainly in the intraband transition energy range. The anisotropy is elucidated in terms of the d-orbitals density of states and the charge distribution with the structure. The anisotropic optical response can be the origin of the discrepancies among reported experimental results for structures with the same stoichiometry.

Dirac 4x1 Wavefunction Recast into a 4x4 Type Wavefunction

As currently understood, the Dirac theory employs a 4 x1 type wavefunction. This 4x1 Dirac wavefunction is acted upon by a 4x4 Dirac Hamiltonian operator, in which process, four independent particle solutions result. Insofar as the real physical meaning and distinction of these four solutions, it is not clear what these solutions really mean. We demonstrate herein that these four independent particle solutions can be brought together under a single roof wherein the Dirac wavefunction takes a new form as a 4x4 wavefunction. In this new formation of the Dirac wavefunction, these four particle solutions precipitate into three distinct and mutuality dependent particles that are eternally bound in the same region of space. Given that Quarks are readily found in a mysterious threesome cohabitation-state eternally bound inside the Proton and Neutron, we make the suggestion that these Dirac particles might be Quarks. For the avoidance of speculation, we do not herein explore this idea further but merely present it as a very interesting idea worthy of further investigation. We however must say that, in the meantime, we are looking further into this very interesting idea, with the hope of making inroads in the immediate future.

Теория гетерогенного катализа. Теория хемосорбции

This monograph is a continuation of the monograph by V.V. Sadovnikov. Lateral interaction. Moscow 2006. Publishing house "Anta-Eco", 2006. ISBN 5-9730-0017-6. In this work, the foundations of the theory of heterogeneous catalysis and the theory of chemisorption are more easily formulated. The book consists of two parts, closely related to each other. These are the theoretical foundations of heterogeneous catalysis and chemisorption. In the theory of heterogeneous catalysis, an experiment is described in detail, which must be carried out in order to isolate the stages of a catalytic reaction, to find the stoichiometry of each of the stages. This experiment is based on the need to obtain the exact value of the specific surface area of the catalyst, the number of centers at which the reaction proceeds, and the output curves of each of the reaction products. The procedures for obtaining this data are described in detail. Equations are proposed and solved that allow calculating the kinetic parameters of the nonequilibrium stage and the thermodynamic parameters of the equilibrium stage. The description of the quantitative theory of chemisorption is based on the description of the motion of an atom along a crystal face. The axioms on which this mathematics should be based are formulated, the mathematical apparatus of the theory is written and the most detailed instructions on how to use it are presented. The first axiom: an atom, moving along the surface, is present only in places with minima of potential energy. The second axiom: the face of an atom is divided into cells, and the position of the atom on the surface of the face is set by one parameter: the cell number. The third axiom: the atom interacts with the surrounding material bodies only at the points of minimum potential energy. The fourth axiom: the solution of the equations is a map of the arrangement of atoms on the surface. The fifth axiom: quantitative equations are based on the concept of a statistically independent particle. The formation energies of these particles and their concentration are calculated by the developed program. The program based on these axioms allows you to simulate and calculate the interaction energies of atoms on any crystal face. The monograph is intended for students, post-graduate students and researchers studying work and working in petrochemistry and oil refining.

Photoelectron Angular Distributions of Nonresonant Two-Photon Atomic Ionization Near Nonlinear Cooper Minima

Photoelectron angular distributions of the two-photon ionization of neutral atoms are theoretically investigated. Numerical calculations of two-photon ionization cross sections and asymmetry parameters are carried out within the independent-particle approximation and relativistic second-order perturbation theory. The dependence of the asymmetry parameters on the polarization and energy of the incident light as well as on the angular momentum properties of the ionized electron are investigated. While dynamic variations of the angular distributions at photon energies near intermediate level resonances are expected, we demonstrate that equally strong variations occur near the nonlinear Cooper minimum. The described phenomena is demonstrated on the example of two-photon ionization of magnesium atom.

Angiopoietin-like protein 3 governs LDL-cholesterol levels through endothelial lipase-dependent VLDL clearance

Angiopoietin-like protein (ANGPTL)3 regulates plasma lipids by inhibiting LPL and endothelial lipase (EL). ANGPTL3 inactivation lowers LDL-C independently of the classical LDLR-mediated pathway and represents a promising therapeutic approach for individuals with homozygous familial hypercholesterolemia due to LDLR mutations. Yet, how ANGPTL3 regulates LDL-C levels is unknown. Here, we demonstrate in hyperlipidemic humans and mice that ANGPTL3 controls VLDL catabolism upstream of LDL. Using kinetic, lipidomic, and biophysical studies, we show that ANGPTL3 inhibition reduces VLDL-lipid content and size, generating remnant particles that are efficiently removed from the circulation. This suggests that ANGPTL3 inhibition lowers LDL-C by limiting LDL particle production. Mechanistically, we discovered that EL is a key mediator of ANGPTL3’s novel pathway. Our experiments revealed that, although dispensable in the presence of LDLR, EL-mediated processing of VLDL becomes critical for LDLR-independent particle clearance. In the absence of EL and LDLR, ANGPTL3 inhibition perturbed VLDL catabolism, promoted accumulation of atypical remnants, and failed to reduce LDL-C. Taken together, we uncover ANGPTL3 at the helm of a novel EL-dependent pathway that lowers LDL-C in the absence of LDLR.

Independent particle and lot selection of increment samples in the theory of sampling

Introduction. The theory of sampling developed by Pierre Gy does not prove the compatibility and consistency of discrete and continuous selection models. Discrete (independent particle) and continuous (lot) selection models are determined by incompatible properties of increment samples, which prevented from creating the consistent theory of sampling. Research methodology. The inconsistencies are removed at assuming the idea that there are differences in both separate ore lumps or mineral-dressing products and any locally selected parts of the rock mass under test called increment samples simultaneously available in any rock mass under test. The said differences are described by independent particle dispersion and increment samples dispersion. Composite sample permissible error formed in both discrete and continuous selection is attained by selection of the number of particles collected into the increment sample or their parts and the number of increment samples. Particle dispersion, increment sample dispersion, the number of particles in an increment sample and the number of increment samples combined in one formula make up the complete formula of the fundamental sampling error. The development of the theory of sampling. Based on the complete formula, the possibility of obtaining minimum masses of various sizes has been shown. Thus, for one and the same preset permissible error and from one and the same massif under test, it is possible to collect minimum mass of 17.55 kg (individual particle selection), minimum mass of 170.3 kg (collecting with the bucket sampler), and minimum mass of 10 g under the individual particle selection of particle parts (which is fulfilled under X-ray fluorescent on-stream analysis of material). Discrete selection of increment samples without particles destruction is an especial case of continuous selection method when it is possible to accept the condition that increment samples dispersion is equal to zero. It is possible under ideal mixing of the massif under test. Discussion. Minimum mass of a sample is not a constant. It is a function of increment sample mass. Minimum mass in individual particle selection can be accepted as a reference value of the minimum mass. In lot selection it can be significantly higher than the reference one, while in case of reducing particle size it can be significantly lower than the reference one.