Characterisation of tribocorrosion behaviour of multilayer PVD coatings

The effect of repassivation on tribocorrosion behaviour of two multilayer coatings of different structures is studied experimentally by measuring the variation of instantaneous open-circuit potential during friction. One coating consists of alternating Cr and CrN layers, while another consists of alternated layers of CrN and ZrN. Analysis of the results showed that friction force, i.e. the rate of the mechanical energy supplied to the material in the contact zone, has no direct influence on the tribocorrosion behaviour; however, the wear rate does strongly influence the tribocorrosion. A simple phenomenological model of repassivation of the multilayer coating is developed assuming “surface coverage” approach. This model establishes the relationship between the rate of mechanical activation of material by friction and the behaviour of the open-circuit potential.     

Initial guess of the solution of dynamic optimization of chemical processes

Numerical methods and software packages for solving dynamic optimization or optimal control problems require a suitable initial estimation of the solution. This paper focuses on problems that arise in chemical processes described by complex dynamics. We present a very simple method, based on Pontryagin’s Minimum Principle, to obtain an initial guess for the solution. Our method presents numerous advantages: it is very easy to programme, it allows a wide range of problems to be addressed, the computation time is very short, the initial guess is very close to the solution and is attracted to a global minimum.     

Observation of B+ --> Lambda c+ Lambda c- K+ and B0 --> Lambda c+ Lambda c- K0 decays

We report the first measurements of the doubly charmed baryonic B decays B --> Lambda c+ Lambda c- K. The B+ --> Lambda c+ Lambda c- K+ decay is observed with a branching fraction of (6.5(-0.9)(+1.0)+/-1.1+/-3.4)x10(-4) and a statistical significance of 15.4sigma. The B0 --> Lambda c+ Lambda c- K0 decay is observed with a branching fraction of (7.9(-2.3)(+2.9)+/-1.2+/-4.1)x10(-4) and a statistical significance of 6.6sigma. The branching fraction errors are statistical, systematic, and the error resulting from the uncertainty of the Lambda c+ --> pK- pi+ decay branching fraction. The analysis is based on 357 fb(-1) of data accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider.     

Observation of new states decaying into Lambda(c)(+)Kappa(-)pi(+) and Lambda(c)(+)Kappa(0)/(s)pi(-)

We report the first observation of two charmed strange baryons that decay into Lambda(c)(+)Kappa(-)pi(+). The broader of the two states is measured to have a mass of 2978.5+/-2.1+/-2.0 MeV/c2 and a width of 43.5+/-7.5+/-7.0 MeV/c2. The mass and width of the narrow state are measured to be 3076.7+/-0.9+/-0.5 MeV/c;{2} and 6.2+/-1.2+/-0.8 MeV/c2, respectively. We also perform a search for the isospin partner states that decay into Lambda(c)(+)Kappa(0)/(s)pi(-) and observe a significant signal at the mass of 3082.8+/-1.8+/-1.5 MeV/c2. The data used for this analysis were accumulated at or near the Upsilon(4S) resonance, using the Belle detector at the e+ e- asymmetric-energy collider KEKB. The integrated luminosity of the data sample used is 461.5 fb(-1).     

Prospecting Quantum Correlations and Examining Teleportation Fidelity in a Pair of Coupled Double Quantum Dots System

The topic of improving the ability of quantum systems to retain non-local features and enhance the efficiency of quantum protocols continues. This study delves into the thermal investigation of quantum correlations and teleportation fidelity of a two-qubit teleported state using excess electrons in a coupled double quantum dots system as a quantum channel. The study employs three reliable quantum quantifiers to prospect the resourcefulness and non-classicality of the system. The findings suggest that preserving quantum correlations and optimizing teleportation fidelity require minimizing tunneling coupling and maximizing Coulomb interaction. The study has significant implications for quantum physics and its practical applications in quantum information processing.     

Electrochemical,In Situ Spectroelectrochemical,In Situ Electrocolorimetric and Electrocatalytic Characterization of Metallophthalocyanines Bearing Four Dioctylaminocarbonyl Biphenyloxy Substituents

This study describes the electrochemical, in situ spectroelectrochemical, in situ electrocolorimetric and electrocatalytic characterization of metallophthalocyanines bearing four dioctylaminocarbonyl biphenyloxy groups (MPc's). While CoPc gives both metal‐based and ring‐based redox processes, ZnPc and CuPc show only ring‐based reduction and oxidation processes. In‐situ electrocolorimetric method was applied to investigate color of the electrogenerated anionic and cationic forms of the complexes. Perchloric acid titrations monitored by cyclic voltammetry and spectrophotometry represent possible electrocatalytic activities of the complexes for hydrogen evolution reaction. CuPc having inactive metal center incorporated into a Nafion film on GCE decreases overpotential of the electrode for H⁺ reduction in aqueous solution.     

Die Berechnung der Schubspannungen in der Bogenscheibe

Ohne Zusammenfassung     

The microwave spectrum of 2,4-dioxabicyclo[3.1.0]hexan-3-one

The R band (26.5–40 GHz) microwave spectrum of 2,4-dioxabicyclo[3.1.0]hexan-3-one is reported. Rotational constants for the ground vibrational state of the common ¹²C₄¹H₄¹⁶O₃ and ¹³C₁, ¹³C₆ isotopically substituted species (the latter observed in natural abundance) have been evaluated. In addition rotational constants of the V_B = 1 to V_B = 5 quanta associated with the bending vibration of the five membered ring have been determined. A partial r_s structure has been calculated:

$\text{r(}\text{C}{}_1\text{?}\text{C}{}_5\text{) = 1.497± 0.016}\text{A}\text{?}\text{, r(}\text{C}{}_1\text{?}\text{C}{}_6\text{) = r(}\text{C}{}_6\text{?}\text{C}{}_5\text{) = 1.522 ± 0.015}\text{A}\text{?}$

,

$\text{∠}\text{C}{}_6\text{C}{}_1\text{C}{}_5\text{= ∠}\text{C}{}_1\text{C}{}_5\text{C}{}_6\text{= 60°32′ ± 1°36′, ∠}\text{C}{}_1\text{C}{}_6\text{C}{}_5\text{= 58°′ ± 1°47′}$

. With certain assumed molecular information a least squares fit yields the following parameters:

$\text{β = 68.5 ± 0.02°, r(}\text{C}{}_1\text{O}{}_2\text{= 1.408 ± 0.004}\text{A}\text{?}$

,

$\text{∠}\text{C}{}_5\text{C}{}_1\text{O}{}_2\text{= 105.8 ± 0.02°, ∠}\text{C}{}_1\text{O}{}_2\text{C}{}_3\text{= 108.10 ± 0.03°}$

,

$\text{∠}\text{O}{}_2\text{C}{}_3\text{O}{}_4\text{= 112.8 ± 0.02°}$

.     

Effect of copper ions on the radiostability of protein-polyelectrolyte mixtures

Aqueous solution of polyacrylic acid (PAA), poly-N-isopropylacrylamide (PNIPAAm), bovine serum albumin (BSA), superoxide dismutase (SOD) and their mixtures (PAA-BSA, PAA-Cu-BSA, PNIPAAm-BSA, PAA-SOD) were irradiated in the presence of oxygen in neutral media (pH 7.0) with ⁶⁰Co γ-rays. In addition, aliquots of aqueous solutions of PAA, PAA-Cu²⁺, BSA and PAA-Cu²⁺-BSA saturated with N₂ and N₂O were also irradiated. The decomposition rate of irradiated solutions were measured by UV-visible spectrophotometry, fluorescence spectroscopy, and high performance liquid chromatography (HPLC). Protective effect of copper ions on radiolysis of aqueous solution of PAA-Cu-BSA and conversion of Cu(II) to Cu(I) was observed. The possible mechanism of this phenomenon is discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Conformational investigations of 6-EXO and 6-ENDO- methylbicyclo[3.1.0] hexan-3-one

R band (26.5–40 GHz) microwave spectra have been recorded for the common isotopic species of 6-endo-methylbicyclo[3.1.0]hexan-3-one and 6-exo-methylbicyclo[3.1.0]hexan-3-one. These spectra are shown to be consistent with a ground vibrational state boat conformation having five membered ring dihedral angles of 7.2 ± 0.3° and 20.5 ± 1.4° respectively. This information is correlated with product quantum yields obtained on photolysis of these molecules.