Broadband dielectric spectroscopy on benzophenone: alpha relaxation, beta relaxation, and mode coupling theory

We have performed a detailed dielectric investigation of the relaxational dynamics of glass-forming benzophenone. Our measurements cover a broad frequency range of 0.1 Hz to 120 GHz and temperatures from far below the glass temperature well up into the region of the small-viscosity liquid. With respect to the alpha relaxation this material can be characterized as a typical molecular glass former with rather high fragility. A good agreement of the alpha relaxation behavior with the predictions of the mode coupling theory of the glass transition is stated. In addition, at temperatures below and in the vicinity of Tg we detect a well-pronounced beta relaxation of Johari-Goldstein type, which with increasing temperature develops into an excess wing. We compare our results to literature data from optical Kerr effect and depolarized light scattering experiments, where an excess-wing like feature was observed in the 1 - 100 GHz region. We address the question if the Cole-Cole peak, which was invoked to describe the optical Kerr effect data within the framework of the mode coupling theory, has any relation to the canonical beta relaxation detected by dielectric spectroscopy.Comment: 11 pages, 7 figures; revised version with new Fig. 5 and some smaller changes according to referees' demand

Dielectric spectroscopy in benzophenone: The beta relaxation and its relation to the mode-coupling Cole-Cole peak

We report a thorough characterization of the glassy dynamics of benzophenone by broadband dielectric spectroscopy. We detect a well pronounced beta relaxation peak developing into an excess wing with increasing temperature. A previous analysis of results from Optical-Kerr-effect measurements on this material within the mode coupling theory revealed a high-frequency Cole-Cole peak. We address the question if this phenomenon also may explain the Johari-Goldstein beta relaxation, a so far unexplained spectral feature inherent to glass-forming matter, mainly observed in dielectric spectra. Our results demonstrate that according to the present status of theory, both spectral features seem not to be directly related.Comment: 4 pages, 3 figures; second version as published; small changes of text according to referee suggestions; title changed according to editor's demand

Cleaning graphene : a first quantum/classical molecular dynamics approach

Graphene outstanding properties created a huge interest in the condensed matter community and unprecedented fundings at the international scale in the hope of application developments. Recently, there have been several reports of incomplete removal of the polymer resists used to transfer as-grown graphene from one substrate to another, resulting in altered graphene transport properties. Finding a large-scale solution to clean graphene from adsorbed residues is highly desirable and one promising possibility would be to use hydrogen plasmas. In this spirit, we couple here quantum and classical molecular dynamics simulations to explore the kinetic energy ranges required by atomic hydrogen to selectively etch a simple residue, a CH3 group, without irreversibly damaging the graphene. For incident energies in the 2-15 eV range, the CH3 radical can be etched by forming a volatile CH4 compound which leaves the surface, either in the CH4 form or breaking into CH3+H fragments, without further defect formation. At this energy, adsorption of H atoms on graphene is possible and further annealing will be required to recover pristine graphene.Comment: 9 figures, 27 page

Oral agreement juridical technique at the stage of contract signing: features and composition

Objective: to analyze the oral contractual legal technique and its component tools, to identify the features of technical and legal tools used at the stage of negotiating a contract.Methods: the dialectical approach to cognition of the legal phenomenon, allowing to analyze it from the point of view of the general theory of law, knowledge of individual branches of law and humanities; formal legal method (analysis of doctrinal provisions and practice of contractual law application), analysis, synthesis, comparison, classification, and other general scientific methods of cognition.Results: based on the analysis of theoretical and legal structures, legislation and practice of its application, conclusions are drawn about the existence of oral contractual legal technology and the criteria for distinguishing its legal tools from those of a non-legal nature. The legal tools of oral contractual legal techniques are expressed in the presence of specific rules for performing certain legally significant actions. These rules are characterized by: a) relative stability; b) direct focus on generating the main legal result: the emergence of rights and obligations in order to meet certain needs of the parties; c) dependence of the tools on the content of the contractual process stage. By the example of negotiating a contract as an important stage of the contractual process, one may regard good faith as the most significant rule in negotiations. The general model of signing a contract is also stable (sending a proposal to sign a contract, agreeing/disagreeing with the offer/agreeing to change the terms of the offer, sending a response to the offer, and signing the contract as a result). Negotiations can be organized in two ways: a) directly (based on the general provisions of Chapter 28 of the Russian Civil Code) and b) step-by-step (by signing an agreement on the procedure for conducting negotiations).Scientific novelty: oral contractual legal techniques rarely become the subject of scientific research. The proposed approach to the analysis of its tools is new for the Russian theory of legal technique.Practical significance: the main provisions and conclusions of the article contribute to the development of the legal technique theory aimed at improving the methods of professional legal activity, including in the field of contract signing

Eddy-current testing of fatigue degradation upon contact fatigue loading of gas powder laser clad NiCrBSi-Cr 3 C 2 composite coating

The possibilities of the eddy-current method for testing the fatigue degradation under contact loading of gas powder laser clad NiCrBSi-Cr 3 C 2 composite coating with 15 wt.% of Cr 3 C 2 additive have been investigated. It is shown that the eddy-current testing of the fatigue degradation under contact loading of the NiCrBSi-15%Cr 3 C 2 composite coating can be performed at high excitation frequencies 72-120 kHz of the eddy-current transducer. At that, the dependences of the eddy-current instrument readings on the number of loading cycles have both downward and upward branches, with the boundary between the branches being 3×10 5 cycles in the given loading conditions. This is caused, on the one hand, by cracking, and, on the other hand, by cohesive spalling and compaction of the composite coating, which affect oppositely the material resistivity and, correspondingly, the eddy-current instrument readings. The downward branch can be used to monitor the processes of crack formation and growth, the upward branch - to monitor the degree of cohesive spalling, while taking into account in the testing methodology an ambiguous character of the dependences of the eddy-current instrument readings on the number of loading cycles. © 2017 Author(s)

Effect of antibodies to glutamate on age-related memory changes in C57Bl/6 mice

Chronic intranasal administration of antibodies to glutamate to aging C57Bl/6 mice improved passive avoidance conditioning, had no effect on horizontal and vertical locomotor activity, but slowed locomotion in the open-field test. Administration of antibodies to glutamate increased the content of dopamine and its metabolites in mouse hippocampus, but had no effect on the metabolism of neurotransmitter amino acids. In the frontal cortex, antibodies to glutamate did not affect neurotransmitter metabolism, but increased the level of both excitatory and inhibitory amino acids without changing their ratio

Процедурная седация и/или анальгезия: обзор литературы

АКТУАЛЬНОСТЬ: За последние десятилетия процедурная седация и/или анальгезия (ПС/ПСА) стала широко применяться с целью проведения диагностических исследований и малоинвазивных хирургических вмешательств во внеоперационных условиях. Представленные данные в литературе по ПС/ПСА содержат противоречивую информацию в отношении показаний, противопоказаний, рисков осложнений, базового уровня мониторинга и целевого уровня седации (ЦУС). ЦЕЛЬ ИССЛЕДОВАНИЯ: Провести анализ существующих практических рекомендаций, рандомизированных клинических исследований (РКИ), обзор данных литературы и систематизировать данные о возможностях использования седативных препаратов и наркотических анальгетиков в рамках процедурной седации. МАТЕРИАЛЫ И МЕТОДЫ: Проведен поиск в электронных базах PubMed, Medline, Embase, eLibrary рекомендаций по ПС/ПСА, РКИ и статей. РЕЗУЛЬТАТЫ: В обзоре литературы описаны уровни седации в порядке возрастания сложности и потенциального риска развития осложнений. Представлена сравнительная характеристика препаратов первой и второй линии для седации и обезболивания. Сформулированы минимальные требования к периоперационному мониторингу жизненно важных показателей, уровня седации и боли. ВЫВОДЫ: ПС/ПСА в плановом или неотложном порядке обеспечивает безопасное, комфортное и успешное выполнение диагностических исследований и малоинвазивных хирургических вмешательств. Принципы взаимодействия и введения седативных препаратов с наркотическими анальгетиками лежат в основе применения схем седации. Использование шкал имеет важное практическое значение для мониторинга динамики уровня седации и более тонкого управления дозами седативных препаратов. Абсолютных противопоказаний для ПС/ПСА нет. ПС/ПСА является востребованным направлением в современной практике анестезиолога-реаниматолога. Отсутствие в Российской Федерации регламентирующих документов по ПС/ПСА диктует необходимость разработки методических рекомендаций

The influence of a combined strain-heat treatment on the features of electromagnetic testing of fatigue degradation of quenched constructional steel

The possibilities of the magnetic and eddy-current methods for testing fatigue degradation during low-cycle loading of quenched steel 50 (0.51% C) that was subjected to a combined strain-heat treatment according to an optimal regime that included friction treatment with subsequent tempering at T = 350 C, were investigated. It is shown that for steel that was subjected to a combined nanostructuring treatment, the accumulation of a plastic strain under "hard" cyclic loading can be tested using the coercimetric method and values of the residual magnetic induction on the major and minor magnetic-hysteresis loops, values of the maximum and initial magnetic permeabilities, and readings of an eddy-current instrument at a low excitation frequency of the eddy-current transducer. The appearance of surface fatigue cracks can be tested via eddy-current measurements at high frequencies, when the contribution of the crack formation in the hardened layer to the eddy-current characteristics is considerable. © 2013 Pleiades Publishing, Ltd

Thermochemical characteristics of the formation of aqueous solutions of imino acids

The calorimetry methods are an important source of thermodynamic information in the physicochemistry of solutions of biologically active substances, including amino acids. The goal of the work was to prepare a thermodynamic description of the formation of an aqueous solution of heterocyclic imino acids, proline and hydroxyproline, that have different structures and sizes of the side radical, in a wide range of concentrations, which can be used for a qualitative analysis of changes occurring in their solutions. Thermochemical measurements of the formation of an aqueous solution of imino acids in the concentration range 1.0·10-3 – 40.0·10-3 mol/kg was performed on a MID-200 differential heat-conducting microcalorimeter at 293 K. The equilibrium moment in the solution formation was determined by the output of the thermokinetic curve to the zero line. The enthalpy of the formation of an aqueous solution of imino acids was calculated by the integration of the time dependence of thermal power. It is shown that the increase in the equilibrium time, the increase in the maximum heat flow, and the decrease in the rate of change of the heat flow during the dissolution of hydroxyproline is due to the formation of intra and intermolecular bonds in the Hypro structure with the participation of the OH group. The difference in the structure of imino acids is reflected in the sign of the thermal effect and the form of the concentration dependence of the enthalpy of formation of aqueous solutions. The exoeffect of proline dissolution is due to the stabilisation of the water structure influenced by imino acid