An estimation of surface vibration excitation cross sections of CO,O and H adsorbed on tungsten

A simple model is described for the evaluation of adatom loss spectra of dipole vibrations perpendicular to the substrate. It considers the inelastic electron scattering before and after specular reflection on the substrate. By comparing the loss to elastic peak area the total cross section σ of the inelastic electron scattering can be estimated. The model was used for evaluating experimental results published in the literature by Ibach, Froitzheim, Adnot, Backx and Barnes on the systems WCO, WO and WH. The main results are: for the CO 258 meV loss peak, σ = (11.6?18.3)×10^?18cm²; for the O 78 meV loss peak, σ = (8.4?16.2) × 10^?18cm²; and for the H 130 and 155 meV loss peaks, σ =(0.73?2.2) × 10^?18cm². They are close to the theoretical values. A reasonable agreement was found between σ values determined on WO and WβCO (dissociated) systems.     

Die Erscheinung der Fraktionierung von Kristallgemischen bei der Kataphorese

Zusammenfassung Wir haben eine bei der kataphoretischen Herstellung von Oxydkathoden aufgetretene Erscheinung untersucht und mit Hilfe von Modellversuchen festgestellt, da? bei der Kataphorese von Suspensionen mit K?rnchen von inhomogener Zusammensetzung eine Fraktionierung der einzelnen Kristallsorten eintritt. Bei den Karbonaten des Bariums, Strontiums und Kalziums besteht diese Fraktionierung darin, da? die kataphoretische Abscheidung der K?rnchen mit Ca-Gehalt langsamer ist als die Abscheidung der K?rnchen mit Ba- und Sr- Gehalt.     

Quantum criticality in a double-quantum-dot system

We discuss the realization of the quantum-critical non-Fermi-liquid state, originally discovered within the two-impurity Kondo model, in double-quantum-dot systems. Contrary to common belief, the corresponding fixed point is robust against particle-hole and various other asymmetries and is unstable only to charge transfer between the two dots. We propose an experimental setup where such charge transfer processes are suppressed, allowing a controlled approach to the quantum-critical state. We also discuss transport and scaling properties in the vicinity of the critical point.     

Typical faces of extremal polytopes with respect to a thin three-dimensional shell

Summary Given <InlineEquation ID=IE"1"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"2"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"3"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"4"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"5"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"6"><EquationSource Format="TEX"><![CDATA[$]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>r>1$, we search for the convex body of minimal volume in $\mathbb{E}^3$ that contains a unit ball, and whose extreme points are of distance at least $r$ from the centre of the unit ball. It is known that the extremal body is the regular octahedron and icosahedron for suitable values of $r$. In this paper we prove that if $r$ is close to one then the typical faces of the extremal body are asymptotically regular triangles. In addition we prove the analogous statement for the extremal bodies with respect to the surface area and the mean width.     

Covering the crosspolytope by equal balls

Summary We determine the minimal radius of <InlineEquation ID=IE"1"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"2"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"3"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"4"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"5"><EquationSource Format="TEX"><![CDATA[$]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>n=2$, $d$ or $2d$ congruent balls, which cover the $d$-dimensional crosspolytope.     

Cosmology with Gravitational Waves: A Review

Standard sirens have been the central paradigm in gravitational-wave cosmology so far. From the gravitational wave signature of compact star binaries, it is possible to measure the luminosity distance of the source directly, and if additional information on the source redshift is provided, a measurement of the cosmological expansion can be performed. This review article discusses several methodologies that have been proposed to use gravitational waves for cosmological studies. Methods that use only gravitational-wave signals and methods that use gravitational waves in conjunction with additional observations such as electromagnetic counterparts and galaxy catalogs will be discussed. The review also discusses the most recent results on gravitational-wave cosmology, starting from the binary neutron star merger GW170817 and its electromagnetic counterpart and finishing with the population of binary black holes, observed with the third Gravitational-wave Transient Catalog GWTC–3.     

Overlapping Modularity at the Critical Point of k-Clique Percolation

One of the most remarkable social phenomena is the formation of communities in social networks corresponding to families, friendship circles, work teams, etc. Since people usually belong to several different communities at the same time, the induced overlaps result in an extremely complicated web of the communities themselves. Thus, uncovering the intricate community structure of social networks is a non-trivial task with great potential for practical applications, gaining a notable interest in the recent years. The Clique Percolation Method (CPM) is one of the earliest overlapping community finding methods, which was already used in the analysis of several different social networks. In this approach the communities correspond to k-clique percolation clusters, and the general heuristic for setting the parameters of the method is to tune the system just below the critical point of k-clique percolation. However, this rule is based on simple physical principles and its validity was never subject to quantitative analysis. Here we examine the quality of the partitioning in the vicinity of the critical point using recently introduced overlapping modularity measures. According to our results on real social and other networks, the overlapping modularities show a maximum close to the critical point, justifying the original criteria for the optimal parameter settings.     

The sequenced structure of amino-alcohol-based random poly(ester amide)s

Journal of Thermal Analysis and Calorimetry - Random amino-alcohol-based poly(ester amide)s were synthesized using adipic acid and differently substituted amino-alcohols, namely 2-amino-ethan-1-ol,...