Категории симметрии и асимметрии в науке о языке

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The practical importance of accounting education for future managers

There is an opinion that accounting is a work on the chronological processing of the data of business transactions that have already occurred at the enterprise. Many applicants are not interested in the accounting profession, considering it narrowly focused, boring, and unprestigious. Although, graduates of accounting specialties have applied knowledge and the ability to implement them in their specialty, as accounting is required by all business entities, without exception, from an individual entrepreneur to transnational corporations. Knowledge and skills in accounting disciplines allow graduates to choose a large number of specialties from an accountant to a financial director or an auditor. Thus, the subject of the research is a set of theoretical and methodological issues regarding the importance of accounting knowledge for managers of various levels of enterprise administration. The purpose of the article is a theoretical justification of the methodological aspects of the importance of acquiring accounting competencies by managers of enterprises

Lithium Manganese Sulfates as a New Class of Supercapattery Materials at Elevated Temperatures

To make supercapattery devices feasible, there is an urgent need to find electrode materials that exhibit a hybrid mechanism of energy storage. Herein, we provide a first report on the capability of lithium manganese sulfates to be used as supercapattery materials at elevated temperatures. Two compositions are studied: monoclinic Li$_2$Mn(SO$_4$)$_2$ and orthorhombic Li$_2$Mn$_2$(SO$_4$)$_3$, which are prepared by a freeze-drying method followed by heat treatment at 500 °C. The electrochemical performance of sulfate electrodes is evaluated in lithium-ion cells using two types of electrolytes: conventional carbonate-based electrolytes and ionic liquid IL ones. The electrochemical measurements are carried out in the temperature range of 20–60 °C. The stability of sulfate electrodes after cycling is monitored by in-situ Raman spectroscopy and ex-situ XRD and TEM analysis. It is found that sulfate salts store Li+ by a hybrid mechanism that depends on the kind of electrolyte used and the recording temperature. Li$_2$Mn(SO$_4$)$_2$ outperforms Li$_2$Mn$_2$(SO$_4$)$_3$ and displays excellent electrochemical properties at elevated temperatures: at 60 °C, the energy density reaches 280 Wh/kg at a power density of 11,000 W/kg. During cell cycling, there is a transformation of the Li-rich salt, Li$_2$Mn(SO$_4$)$_2$, into a defective Li-poor one, Li$_2$Mn$_2$(SO$_4$)$_3$, which appears to be responsible for the improved storage properties. The data reveals that Li$_2$Mn(SO$_4$)$_2$ is a prospective candidate for supercapacitor electrode materials at elevated temperatures

Review and new perspectives on non-layered manganese compounds as electrode material for Sodium-Ion batteries

After more than 30 years of delay compared to lithium-ion batteries, sodium analogs are now emerging in the market. This is a result of the concerns regarding sustainability and production costs of the former, as well as issues related to safety and toxicity. Electrode materials for the new sodium-ion batteries may contain available and sustainable elements such as sodium itself, as well as iron or manganese, while eliminating the common cobalt cathode compounds and copper anode current collectors for lithium-ion batteries. The multiple oxidation states, abundance, and availability of manganese favor its use, as it was shown early on for primary batteries. Regarding structural considerations, an extraordinarily successful group of cathode materials are layered oxides of sodium, and transition metals, with manganese being the major component. However, other technologies point towards Prussian blue analogs, NASICON-related phosphates, and fluorophosphates. The role of manganese in these structural families and other oxide or halide compounds has until now not been fully explored. In this direction, the present review paper deals with the different Mn-containing solids with a non-layered structure already evaluated. The study aims to systematize the current knowledge on this topic and highlight new possibilities for further study, such as the concept of entatic state applied to electrodes

Redox Hyperactive MOF for Li+, Na+ and Mg2+ Storage

To create both greener and high-power metal-ion batteries, it is of prime importance to invent an unprecedented electrode material that will be able to store a colossal amount of charge carriers by a redox mechanism. Employing periodic DFT calculations, we modeled a new metal-organic framework, which displays energy density exceeding that of conventional inorganic and organic electrodes, such as Li- and Na-rich oxides and anthraquinones. The designed MOF has a rhombohedral unit cell in which an Ni(II) node is coordinated by 2,5-dicyano-p-benzoquinone linkers in such a way that all components participate in the redox reaction upon lithiation, sodiation and magnesiation. The spatial and electronic changes occurring in the MOF after the interaction with Li, Na and Mg are discussed on the basis of calculated electrode potentials versus Li0/Li+, Na0/Na+ and Mg0/Mg2+, respectively. In addition, the specific capacities and energy densities are calculated and used as a measure for the electrode applicability of the designed material. Although the highest capacity and energy density are predicted for Li storage, the greater structural robustness toward Na and Mg uptake suggests a higher cycling stability in addition to lower cost. The theoretical results indicate that the MOF is a promising choice for a green electrode material (with <10% heavy metal content) and is well worth experimental testing

Metal Substitution versus Oxygen-Storage Modifier to Regulate the Oxygen Redox Reactions in Sodium-Deficient Three-Layered Oxides

Sodium-deficient nickel-manganese oxides with three-layered stacking exhibit the unique property of dual nickel-oxygen redox activity, which allows them to achieve enormous specific capacity. The challenge is how to stabilize the oxygen redox activity during cycling. This study demonstrates that oxygen redox activity of P3-Na2/3Ni1/2Mn1/2O2 during both Na+ and Li+ intercalation can be regulated by the design of oxide architecture that includes target metal substituents (such as Mg2+ and Ti4+) and oxygen storage modifiers (such as CeO2). Although the substitution for nickel with Ti4+ amplifies the oxygen redox activity and intensifies the interaction of oxides with NaPF6- and LiPF6-based electrolytes, the Mg2+ substituents influence mainly the nickel redox activity and suppress the deposition of electrolyte decomposed products (such as MnF2). The CeO2-modifier has a much stronger effect on the oxygen redox activity than that of metal substituents; thus, the highest specific capacity is attained. In addition, the CeO2-modifier tunes the electrode–electrode interaction by eliminating the deposition of MnF2. As a result, the Mg-substituted oxide modified with CeO2 displays high capacity, excellent cycling stability and exceptional rate capability when used as cathode in Na-ion cell, while in Li-ion cell, the best performance is achieved for Ti-substituted oxide modified by CeO2