110 research outputs found

    Фізичний та психічний примус як обставина, що обтяжує покарання

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    Касьян, А. О. Фізичний та психічний примус як обставина, що обтяжує покарання / А. О. Касьян // Європейські перспективи. – 2014. – № 8. – С. 107-112.У статті на підставі аналізу правової природи фізичного та психічного примусу обґрунтовується доцільність його законодавчого закріплення як обставини, що обтяжує покарання.In the article on the basis of analysis of the legal nature of the physical and psychical coercion expediency its legislative recognition as a circumstance aggravating penalty.В статье на основании анализа правовой природы физического и психического принуждения обосновывается целесообразность его законодательного закрепления в качестве обстоятельства отягчающего наказание

    Correlating atom probe tomography with x-ray and electron spectroscopies to understand microstructure-activity relationships in electrocatalysts

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    The search for a new energy paradigm with net-zero carbon emissions requires new technologies for energy generation and storage that are at the crossroad between engineering, chemistry, physics, surface and materials sciences. To keep pushing the inherent boundaries of device performance and lifetime, we need to step away from a cook-and-look approach and aim to establish the scientific ground to guide the design of new materials. This requires strong efforts in establishing bridges between microscopy and spectroscopy techniques, across multiple scales. Here, we discuss how the complementarities of X-ray- and electron-based spectroscopies and atom probe tomography can be exploited in the study of surfaces and sub-surfaces to understand structure-property relationships in electrocatalysts

    Mechanistische Untersuchungen der elektrochemischen Sauerstoffentwicklung auf Modellelektroden; Stabilität der Elektroden, Natur der Oxide und Intermediate

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    Diagramme Sonstige Körperschaft, die mit dem Werk in Verbindung steht dem Förderkatalog entnommen Förderkennzeichen BMBF 03SF0507 Unterschiede zwischen dem gedruckten Dokument und der elektronischen Ressource können nicht ausgeschlossen werden Langzeitarchivierung durch Technische Informationsbibliothek (TIB) / Leibniz-Informationszentrum Technik und Naturwissenschaften und Universitätsbibliothe

    Chemical Partitioning at Crystalline Defects in PtAu as a Pathway to Stabilize Electrocatalysts

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    Dissolution of electrocatalysts during long-term and dynamic operation is a challenging problem in energy conversion and storage devices such as fuel cells and electrolyzers. To develop stable electrocatalysts, we adopt the design concept of segregation engineering, which uses solute segregation prone to electrochemical dissolution at internal defects, i.e., grain boundaries and dislocations. We showcase the feasibility of this approach by stabilizing a model Pt catalyst with an addition of more noble Au (approximately 5 atomic percent). We characterized the defects' nanoscale structure and chemistry, and monitored the electrochemical dissolution of Pt and PtAu alloys by online inductively coupled plasma mass spectrometry. Once segregated to defects, Au atoms can stabilize and hence passivate the most vulnerable sites against electrochemical dissolution and improve the stability and longevity of the Pt electrocatalysts by more than an order of magnitude. This opens pathways to use solute segregation to defects for the development of more stable nanoscale electrocatalysts, a concept applicable for a wide range of catalytic systems

    Controlled Doping of Electrocatalysts through Engineering Impurities

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    Fuel cells recombine water from H-2 and O-2 thereby can power, for example, cars or houses with no direct carbon emission. In anion-exchange membrane fuel cells (AEMFCs), to reach high power densities, operating at high pH is an alternative to using large volumes of noble metals catalysts at the cathode, where the oxygen-reduction reaction occurs. However, the sluggish kinetics of the hydrogen-oxidation reaction (HOR) hinders upscaling despite promising catalysts. Here, the authors observe an unexpected ingress of B into Pd nanocatalysts synthesized by wet-chemistry, gaining control over this B-doping, and report on its influence on the HOR activity in alkaline conditions. They rationalize their findings using ab initio calculations of both H- and OH-adsorption on B-doped Pd. Using this "impurity engineering" approach, they thus design Pt-free catalysts as required in electrochemical energy conversion devices, for example, next generations of AEMFCs, that satisfy the economic and environmental constraints, that is, reasonable operating costs and long-term stability, to enable the "hydrogen economy.

    Fused Filament Fabrication Based Additive Manufacturing of Commercially Pure Titanium

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    Fabrication of titanium components is very cost intensive, partly due to the complex machining and limited recyclability of waste material. For electrochemical applications, the excellent corrosion resistance of pure titanium is of high importance, whereas medium mechanical strength of fabricated parts is sufficient for such a use case. For smaller parts, metal fused filament fabrication MF3 enables the fabrication of complex metallic structures densified during a final sintering step. Pure titanium can be processed to near net shape geometries for electrochemical applications if the parameters and the atmosphere during sintering are carefully monitored. Herein, the influence of thermal debinding and sintering parameters on the fabrication of high density pure titanium using MF3 is investigated. Particular focus is placed on enhancing sintered density while limiting impurity uptake to conserve the high chemical purity of the initial powder material. Relative densities of 95 are repeatedly reached inside the bulk of the samples. An oxygen content of 0.56 amp; 8201;wt as a result of vacuum processing induces the formation of the retained amp; 945; Ti phase 925 amp; 8201;HV0.2 inside the amp; 945; matrix 295 amp; 8201;HV0.2 . Fabricated parts exhibit high mechanical strength, albeit reduced elongation due to remaining pores, and, in terms of electrochemistry, enhanced stability toward anodic dissolutio

    Probing catalytic surfaces by correlative scanning photoemission electron microscopy and atom probe tomography

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    The chemical composition and the electronic state of the surface of alloys or mixed oxides with enhanced electrocatalytic properties are usually heterogeneous at the nanoscale. The non-uniform distribution of the potential across their surface affects both activity and stability. Studying such heterogeneities at the relevant length scale is crucial for understanding the relationships between structure and catalytic behaviour. Here, we demonstrate an experimental approach combining scanning photoemission electron microscopy and atom probe tomography performed at identical locations to characterise the surface's structure and oxidation states, and the chemical composition of the surface and sub-surface regions. Showcased on an Ir-Ru thermally grown oxide, an efficient catalyst for the anodic oxygen evolution reaction, the complementary techniques yield consistent results in terms of the determined surface oxidation states and local oxide stoichiometry. Significant chemical heterogeneities in the sputter-deposited Ir-Ru alloy thin films govern the oxide's chemistry, observed after thermal oxidation both laterally and vertically. While the oxide grains have a composition of Ir0.94Ru0.06O2, the composition in the grain boundary region varies from Ir0.70Ru0.30O2 to Ir0.40Ru0.60O2 and eventually to Ir0.75Ru0.25O2 from the top surface into the depth. The influence of such compositional non-uniformities on the catalytic performance of the material is discussed, along with possible engineering levers for the synthesis of more stable and reactive mixed oxides. The proposed method provides a framework for investigating materials of interest in the field of electrocatalysis and beyond

    Intermolecular interactions of decamethoxinum and acetylsalicylic acid in systems of various complexity levels

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    Intermolecular interactions between decamethoxinum (DEC) and acetylsalicylic acid (ASА) have been studied in the phospholipid-containing systems of escalating complexity levels. The host media for these substances were solvents, L-α-dipalmitoylphosphatidylcholine (DPPC) membranes, and samples of human erythrocytes. Peculiar effects caused by DEC-ASА interaction have been observed in each system using appropriate techniques: (a) DEC-ASА non-covalent complexes formation in DPPC-containing systems were revealed by mass spectrometry with electrospray ionization; (b) joint DEC-ASА action on DPPC model membranes led to increasing of membrane melting temperature Tm, whereas individual drugs caused pronounced Tm decreasing, which was demonstrated by differential scanning calorimetry; (c) deceleration of DEC-induced haemolysis of erythrocytes under joint DEC-ASА application was observed by optical microscopy

    Operando Structure Activity Stability Relationship of Iridium Oxides during the Oxygen Evolution Reaction

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    Creating active and stable electrodes is an essential step toward efficient and durable electrolyzers. To achieve this goal, understanding what aspects of the electrode structure dictate activity and catalyst dissolution is key. Here, we investigate these aspects by studying trends in the activity, stability, and operando structure of iridium oxides during the oxygen evolution reaction. Using operando X-ray photoelectron and X-ray absorption spectroscopy, we determined the near-surface structure of oxides ranging from amorphous to crystalline during the reaction. We show that applying oxygen evolution potentials universally yields deprotonated μ2-O moieties and a μ1-O/μ1-OH mixture, with universal deprotonation energetics but in different amounts. This quantitative difference mainly results from variations in deprotonation depth: surface deprotonation for crystalline IrO2 versus near-surface deprotonation for semicrystalline and amorphous IrOx. We argue that both surface deprotonation and subsurface deprotonation modify the barrier for the oxygen evolution and Ir dissolution reactions, thus playing an important role in catalyst performance
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