New Classification Theory for Topological Gapless Superconducting Nodes

2021 ◽  
Vol 1 ◽  
Keyword(s):  
Angular Momentum ◽  
Crystal Symmetry ◽  
Classification Theory ◽  
Superconducting Gap ◽  
New Classification

A new classification theory on topological superconducting gap nodes predicts two new gap structures emerging from a nonsymmorphic crystal symmetry and angular momentum.

scholarly journals Issues surrounding the classification of accounting information

2011 ◽  
Vol 12 (3) ◽  
pp. 353-369 ◽  
Author(s):  
Huibrecht Van der Poll ◽  
Daan Gouws
Keyword(s):  
Balance Sheet ◽  
Accounting Information ◽  
Financial Statements ◽  
Classification Theory ◽  
New Classification ◽  
Second Nature ◽  
Classification Framework ◽  
Income Statement ◽  
Current Classification

The act of classifying information created by accounting practices is ubiquitous in the accounting process; from recording to reporting, it has almost become second nature. The classification has to correspond to the requirements and demands of the changing environment in which it is practised. Evidence suggests that the current classification of items in financial statements is not keeping pace with the needs of users and the new financial constructs generated by the industry. This study addresses the issue of classification in two ways: by means of a critical analysis of classification theory and practices and by means of a questionnaire that was developed and sent to compilers and users of financial statements. A new classification framework for accounting information in the balance sheet and income statement is proposed.

scholarly journals BASIC CLASSIFIERS OF FORMAL CLASSIFICATION THEORY OF TECHNICAL SYSTEMS: HIERARCHIES, VECTORS AND MATRICES, BANDS

2021 ◽  
Vol 2021 (3) ◽  
pp. 28-40
Author(s):  
Natalia Fedorova
Keyword(s):  
Hierarchical Classification ◽  
Classification Theory ◽  
Unified Approach ◽  
Characteristic Parameters ◽  
New Classification ◽  
Discrete Band ◽  
Formal Classification ◽  
The Matrix ◽  
Technical Systems ◽  
Structure Dimension

The article considers the importance of a technical system among other technical systems in order to ensure its functioning and development, to classify objects, subjects, processes of the technical and related systems. Previously, the author presented the basics of the formal classification theory. This article describes the basic classifiers and operations with them. Three types of basic classifications are identified: discrete hierarchical, discrete matrix and continuous band classifications. For them the concept, structure, dimension, basic operations (addition, multiplication, equality) are defined. In the hierarchy, the classification attributes can be sorted by subordination, when the classification attributes of the lower levels of the hierarchy detail the features of higher levels. The dimension of the hierarchical classification is the number of levels of classification features. Matrix classifications (including vector and super-matrix) are used when the classification attributes are equal and their values are discrete. Band classifications are similar in structure to matrix classifications, but the value of the classification attribute is the interval of numbers, for which the lower and upper boundaries are determined. The dimension of the matrix and band classifications is equal to the number of non-subordinate classification attributes. For all classifications, multiplication is equivalent to the introduction of new classification attributes, addition is the introduction of new values of already existing classification attributes. A unified approach to various types of classifications makes it possible to plan the structure of classifications of specific technical systems, taking into account the properties of characteristic parameters

Microstructure and crystal symmetry of Pb2Sr2(Y/Ca)Cu3O9−δ

1990 ◽  
Vol 48 (4) ◽  
pp. 64-65
Author(s):  
Y. P. Lin ◽  
J. S. Xue ◽  
J. E. Greedan
Keyword(s):  
Electron Diffraction ◽  
High Temperature Superconductors ◽  
Carbon Film ◽  
Basic Structure ◽  
Crystal Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
New Family ◽  
Convergent Beam

A new family of high temperature superconductors based on Pb2Sr2YCu3O9−δ has recently been reported. One method of improving Tc has been to replace Y partially with Ca. Although the basic structure of this type of superconductors is known, the detailed structure is still unclear, and various space groups has been proposed. In our work, crystals of Pb2Sr2YCu3O9−δ with dimensions up to 1 × 1 × 0.25.mm and with Tc of 84 K have been grown and their superconducting properties described. The defects and crystal symmetry have been investigated using electron microscopy performed on crushed crystals supported on a holey carbon film.Electron diffraction confirmed x-ray diffraction results which showed that the crystals are primitive orthorhombic with a=0.5383, b=0.5423 and c=1.5765 nm. Convergent Beam Electron Diffraction (CBED) patterns for the and axes are shown in Figs. 1 and 2 respectively.

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