In-situ electrochemical quantification of active sites in Fe-N/C non-precious metal catalysts

The economic viability of low temperature fuel cells as clean energy devices is enhanced by the development of inexpensive oxygen reduction reaction catalysts. Heat treated iron and nitrogen containing carbon based materials (Fe–N/C) have shown potential to replace expensive precious metals. Although significant improvements have recently been made, their activity and durability is still unsatisfactory. The further development and a rational design of these materials has stalled due to the lack of an in situ methodology to easily probe and quantify the active site. Here we demonstrate a protocol that allows the quantification of active centres, which operate under acidic conditions, by means of nitrite adsorption followed by reductive stripping, and show direct correlation to the catalytic activity. The method is demonstrated for two differently prepared materials. This approach may allow researchers to easily assess the active site density and turnover frequency of Fe–N/C catalysts

A catalyst layer optimisation approach using electrochemical impedance spectroscopy for PEM fuel cells operated with pyrolysed transition metal-N-C catalysts

AbstractThe effect of the ionomer to carbon (I/C) ratio on the performance of single cell polymer electrolyte fuel cells is investigated for three different types of non-precious metal cathodic catalysts. Polarisation curves as well as impedance spectra are recorded at different potentials in the presence of argon or oxygen at the cathode and hydrogen at the anode. It is found that a optimised ionomer content is a key factor for improving the performance of the catalyst. Non-optimal ionomer loading can be assessed by two different factors from the impedance spectra. Hence this observation could be used as a diagnostic element to determine the ideal ionomer content and distribution in newly developed catalyst-electrodes. An electrode morphology based on the presence of inhomogeneous resistance distribution within the porous structure is suggested to explain the observed phenomena. The back-pressure and relative humidity effect on this feature is also investigated and supports the above hypothesis. We give a simple flowchart to aid optimisation of electrodes with the minimum number of trials

Kinetic isotope effect in the oxygen reduction reaction (ORR) over Fe-N/C catalysts under acidic and alkaline conditions.

Heat treated Fe-N/C materials which are highly effective oxygen reduction catalysts in alkaline and acid, show a significant kinetic isotope effect (KIE). The values in acid (~3.4) and alkaline (~2.5) are much larger than the value for the metal free catalyst in acid (~1.8) suggesting that the rate determining step (RDS) is a proton coupled electron transfer in acid with a significant pathway involving a proton independent step under an alkaline environmen

Competition for Graphene: Graphynes with Direction-Dependent Dirac Cones

The existence of Dirac cones in the band structure of two-dimensional materials accompanied by unprecedented electronic properties is considered to be a unique feature of graphene related to its hexagonal symmetry. Here, we present other two-dimensional carbon materials, graphynes, that also possess Dirac cones according to first-principles electronic structure calculations. One of these materials, 6,6,12-graphyne, does not have hexagonal symmetry and features two self-doped nonequivalent distorted Dirac cones suggesting electronic properties even more amazing than that of graphene

Enhanced relativistic-electron beam collimation using two consecutive laser pulses

The double laser pulse approach to relativistic electron beam (REB) collimation has been investigated at the LULI-ELFIE facility. In this scheme, the magnetic field generated by the first laser-driven REB is used to guide a second delayed REB. We show how electron beam collimation can be controlled by properly adjusting laser parameters. By changing the ratio of focus size and the delay time between the two pulses we found a maximum of electron beam collimation clearly dependent on the focal spot size ratio of the two laser pulses and related to the magnetic field dynamics. Cu-K alpha and CTR imaging diagnostics were implemented to evaluate the collimation effects on the respectively low energy ( MeV) components of the REB

Роль юридической ответственности в реализации принципа единства публичной власти в Российской Федерации

The subject. The article presents a comprehensive general theoretical analysis of the institution of legal responsibility and its role, taking into account the consolidation of the new constitutional and legal principle of the unity of the system of public power.The purpose of the research is to confirm or disprove hypothesis that it is necessary to legislate a full-fledged mechanism of legal responsibility of state bodies and local self-government bodies in order to implement the constitutional principle of the unity of public power.Methodology. The formal legal method, the method of comparative legal analysis, dialectical method and systemic approach were used.The main results, scope of application. The authors found the manifestation of dualism in the work of the institution of legal responsibility. It consists in the ability to bear responsibility both to the state, in connection with various offenses, and to the population itself. A brief description of the loss of trust as a basis for the responsibility of officials is given, taking into account contemporary legislation. Directions for the further development of this legal institution are highlighted. The article examines the opinion of the Russian Constitutional Court on the legitimacy of using the loss of trust as a basis for the responsibility of public authorities. The article examines the normative legal acts, which fix the mechanism for the implementation of the principle of maintaining trust in the activities of the authorities on the part of society. For example, in relation to state civil and municipal employees, a prohibition has been established on statements about the activities of authorities and their assessment, if such actions are not included in the list of their official duties. Such a mechanism for maintaining public confidence in the work of government bodies should contribute to strengthening the unity of the public power system. At the same time we can talk about the existing trend towards a decrease in the level of public confidence in the work of authorized bodies exercising public authority. The corruption and bureaucratization of the activities of officials, the expansion of the powers of law enforcement agencies, a decrease in the independence of the political opposition are pointed to among the possible reasons most often. In this regard, the paper proposes expanding the grounds for responsibility when implementing the procedure for recalling an official.Conclusions. It is necessary to consolidate a full-fledged legislative mechanism of legal responsibility of state bodies and local self-government bodies, which will contribute to the implementation and strengthening of the new principle of the unity of public authority.Проводится комплексный общетеоретический анализ института юридической ответственности и его роли с учетом закрепления нового конституционно-правового принципа единства системы публичной власти. По результатам изучения характерных признаков органов публичной власти делается вывод о проявлении дуализма в работе института юридической ответственности. Дается краткая характеристика утраты доверия в качестве основания реализации мер ответственности в отношении должностных лиц и выделяются направления дальнейшего развития этого правового института. Делается вывод о необходимости законодательного закрепления полноценного механизма юридической ответственности государственных органов и органов местного самоуправления, что будет свидетельством реализации и дальнейшего укрепления нового конституционного принципа единства публичной власти

Реализация юридической ответственности в правосознании и правовой культуре

The subject of the study of the article is the legal foundations of the institution of legal responsibility and the features of its interaction with legal consciousness and legal culture. The goal is to substantiate the need for effective legal regulation of legal liability, taking into account the existing forms of interaction with legal consciousness. The work carried out a comprehensive general theoretical analysis of the institution of legal responsibility and its role in the process of formation and development of the legal consciousness of citizens. The team of authors in the process of studying the place and role of legal liability in the legal system came to the conclusion that there is a relationship between the category under consideration and legal consciousness in the process of implementing legal acts that provide for measures of legal liability. The problem of a low level of legal culture can manifest itself not only in legislative and law enforcement activities. Shortcomings in the implementation of the official interpretation of legal norms and execution of the relevant act in some cases can also cause unlawful consequences, among which are: unlawful prosecution, exemption from liability in violation of established procedures, etc. In the course of the study, a whole set of methods of scientific knowledge was used, among which one can single out: the formal-legal method, the method of comparative legal analysis, systemic, dialectical and others. As a result of the research, it was found that there is a direct connection between the signs of positive responsibility and legal consciousness. In the absence of a high level of legal awareness, which would include both intellectual (views, ideas) and psychological (emotions, feelings) aspects, the implementation of the positive aspect of legal responsibility becomes impossible. It has been proven that positive responsibility, together with legal consciousness, contains volitional and intellectual aspects. The team of authors put forward an opinion according to which the positive responsibility of the individual can be represented as a mental attitude in the form of a sense of duty and the need to fulfill the existing duties to the required extent. Such a sense of duty will be available to the subject only in the absence of a struggle of motives, which is excluded in the developed general legal culture of the individual and society as a whole. Assimilation of the requirements of the law is a prerequisite for the presence of responsible behavior and legal awareness. Based on the results of the study of legal responsibility and legal culture, a conclusion is made about the close interaction of these categories and the need for the legislator to take into account such a connection when exercising his law-making powers. A brief description of positive legal liability with the establishment of its characteristic features is also given. Thanks to the study of the relationship between legal responsibility and legal consciousness, it was revealed that the level of culture will grow if the ideas of social justice, democracy and the rule of law are reflected in law.С целью обоснования необходимости эффективного правового регулирования юридической ответственности с учетом имеющихся форм взаимодействия с правосознанием исследуются правовые основы института юридической ответственности и особенности его взаимодействия с правосознанием и правовой культурой. Проводится комплексный общетеоретический анализ института юридической ответственности и его роли в процессе формирования и развития правосознания граждан. В ходе исследования применялись такие методы научного познания, как формально-юридический, сравнительно-правовой, системный, диалектический и иные. По результатам исследования юридической ответственности и правовой культуры делается вывод о тесном взаимодействии этих категорий и необходимости для законодателя учитывать подобную связь при реализации своих правотворческих полномочий. Также дана краткая характеристика позитивной юридической ответственности во взаимосвязи с правосознанием

Юридическая аномия в правовой системе: теоретико-методологические основы исследования

A comprehensive general theoretical analysis of legal anomie in the legal system of modern Russian society is carried out. It is said that the theory of state and law currently lacks even the foundations of a holistic concept of legal anomie, but it is precisely this that acts as one of the causes of corruption, terrorism, extremism, legal irresponsibility, a high level of delinquency, massive non-compliance with prohibitions, distancing a significant number of citizens from state power and its rejection. The authors note that anomie to one degree or another always exists. At the same time, the state of social anomie inevitably increases when significant changes occur that affect the social structure and norms. Anomie is an interdisciplinary category that requires appropriate approaches to itself. Social anomie is based on the general interdisciplinary concept of "social deviations", which is studied by a variety of sciences: philosophy, sociology, psychology and many others. A brief description of the theoretical and methodological foundations of the study of social deviations, social anomie and its specific variety - legal anomie is given. For the most complete analysis of legal anomie, it is proposed to use not only systemic (within the category "legal system"), but also comprehensive (within the category "social and legal life") approaches, as well as a number of other methods (in particular, historical, structural and functional and statistical). Legal anomie manifests itself in the form of a decline in the value of law and order, a discrepancy between the goals of society and the means to achieve them offered by the state, the lack of trust between society and public authorities, sustainable legal nihilism. And if in sociology (and some other sciences) there are different directions and concepts for understanding anomie, then in the theory of state and law, a system of scientific knowledge about legal anomie has not yet been formed. Legal anomie in the legal system should be considered comprehensively, in development and comparison, revealing the contradictions and mutual conditionality of its various characteristics, possible pairing, as well as the positive and negative aspects of the existing contradictions between legal anomie and individual elements of the legal system of society. Due to the fact that legal anomie in modern society (following the social and legal life) develops and becomes more complicated, it is concluded that it is necessary to further study it, which will provide: firstly, its more complete knowledge and prediction of consequences, and secondly, the development of effective preventive measures, and, thirdly, the strengthening of counteraction to it.Проводится комплексный общетеоретический анализ юридической аномии в правовой системе современного российского общества. Дается краткая характеристика теоретико-методологических основ исследования социальных отклонений, социальной аномии и ее специфической разновидности – аномии юридической. Для наиболее полного анализа юридической аномии предлагается использовать не только системный (в рамках категории «правовая система»), но и комплексный (в рамках категории «социально-правовая жизнь») подходы, а также ряд иных методов (в частности, исторический, структурно-функциональный, статистический и др.). Делается вывод о необходимости исследования аномии, что обеспечит: во-первых, ее более полное познание и прогнозирование последствий, во-вторых, выработку действенных профилактических мер и, в-третьих, усиление противодействия ей

Measurements of Extended Magnetic Fields in Laser-Solid Interaction

Magnetic fields generated from a laser-foil interaction are measured with high fidelity using a proton radiography scheme with in situ x-ray fiducials. In contrast to prior findings under similar experimental conditions, this technique reveals the self-generated, Biermann-battery fields extend beyond the edge of the expanding plasma plume to a radius of over 3.5 mm by t=+1.4 ns, a result not captured in state-of-the-art magneto-hydrodynamics simulations. An analysis of two mono-energetic proton populations confirms that proton deflection is dominated by magnetic fields far from the interaction (>2 mm) and electric fields are insignificant. Comparisons to prior work suggest a new physics mechanism for the magnetic field generation and transport in laser-solid interactions.Comment: 9 pages, 8 figure