scholarly journals Measurement of Corner-Mode Coupling in Acoustic Higher-Order Topological Insulators

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiao Li ◽  
Shiqiao Wu ◽  
Guanqing Zhang ◽  
Wanzhu Cai ◽  
Jack Ng ◽  
...  
Keyword(s):  
Topological Insulators ◽  
Dipole Moments ◽  
Higher Order ◽  
Square Lattice ◽  
Topological Invariants ◽  
Different Types ◽  
Recent Developments ◽  
The Difference ◽  
Response Line ◽  
Topological Boundary

Recent developments of band topology have revealed a variety of higher-order topological insulators (HOTIs). These HOTIs are characterized by a variety of different topological invariants, making them different at a fundamental level. However, despite such differences, the fact that they all sustain higher-order topological boundary modes poses a challenge to phenomenologically tell them apart. This work presents experimental measurements of the coupling effects of topological corner modes (TCMs) existing in two different types of two-dimensional acoustic HOTIs. Although both HOTIs have a similar four-site square lattice, the difference in magnetic flux per unit cell dictates that they belong to different types of topologically nontrivial phases—one lattice possesses quantized dipole moments, but the other is characterized by quantized quadrupole moment. A link between the topological invariants and the response line shape of the coupled TCMs is theoretically established and experimentally confirmed. Our results offer a pathway to distinguish HOTIs experimentally.

Recent Developments in Hydraulic Couplings

1935 ◽  
Vol 130 (1) ◽  
pp. 75-190 ◽  
Author(s):  
Harold Sinclair
Keyword(s):  
Test Data ◽  
Good Deal ◽  
Hydraulic Coupling ◽  
Different Types ◽  
Recent Developments ◽  
History Of ◽  
Torque Converters ◽  
The Difference

The use of hydraulic couplings in practically all fields of engineering has increased rapidly during the last few years. The paper traces the history of the Vulcan-Sinclair hydraulic coupling, which is of the turbo or hydro-kinetic type, from the days of its inception up to the present time, and gives details of other designs of the displacement or hydro-static type that have been developed, and the principles upon which they operate. The main advantages of the turbo design are enumerated and considerable test data are given, with particular reference to the Vulcan coupling, which, in theory, is the forerunner of the Vulcan-Sinclair designs. Advantage is taken to explain the difference between fluid couplings and torque converters, concerning which a good deal of confusion exists. The differences between the various types of Vulcan-Sinclair hydraulic couplings and the improvements that have been effected in design during recent years are described in detail. The paper deals comprehensively with numerous applications of the different types of couplings covering both the industrial and automotive fields. The difficulties, and their cures, which have arisen in connexion with a number of applications are given prominence. A section deals with change-speed gearboxes arranged in conjunction with hydraulic couplings for use in Diesel traction.

scholarly journals Convex sequences of higher order

Filomat ◽  
2018 ◽  
Vol 32 (13) ◽  
pp. 4655-4663
Author(s):  
Daniel Sofonea ◽  
Ioan Ţincu ◽  
Ana Acu
Keyword(s):  
Real Number ◽  
Sufficient Conditions ◽  
Higher Order ◽  
Necessary And Sufficient Conditions ◽  
Difference Operators ◽  
Real Sequence ◽  
Convex Sequence ◽  
Different Types ◽  
The Difference ◽  
Necessary And Sufficient

In this paper we study the class of convex sequences of higher order defined using the difference operators and investigate their properties. The notion of the convex sequence of order r ? N will be extended for r a real number. Some necessary and sufficient conditions such that a real sequence belongs to the class of convex sequences of higher order r ? R are introduced. Using different types of means we will investigate the convexity of higher order for real sequences.

scholarly journals Classification of topological invariants related to corner states

2021 ◽  
Vol 111 (5) ◽  
Author(s):  
Shin Hayashi
Keyword(s):  
Periodic Table ◽  
Topological Insulators ◽  
Higher Order ◽  
Topological Invariants ◽  
Bulk Surface ◽  
Definition Of

AbstractWe discuss some bulk-surface gapped Hamiltonians on a lattice with corners and propose a periodic table for topological invariants related to corner states aimed at studies of higher-order topological insulators. Our table is based on four things: (1) the definition of topological invariants, (2) a proof of their relation with corner states, (3) computations of K-groups and (4) a construction of explicit examples.

scholarly journals A Concise Study on Shearing Operation in Metal Forming

2021 ◽  
Vol 309 ◽  
pp. 01004
Author(s):  
M. Ikumapayi Omolayo ◽  
A. Afolalu Sunday ◽  
S. Fatoba Olawale ◽  
A. Kazeem Rasaq ◽  
A. Adetunla Adedotun ◽  
...  
Keyword(s):  
Metal Forming ◽  
Improve Efficiency ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Recent Advancement ◽  
Recent Developments ◽  
The Difference ◽  
Over Time

This study outlines the recent developments in metal forming processes, focusing mainly on the shearing process. A summary of the background of the shearing process is given to give perspective on how such a process has changed over time. It explains what shearing operations are and how the shearing process is operated in metal forming. While also outlining the difference between shearing, slitting, punching, notching, and blanking processes, and the advantages and disadvantages of the shearing process are detailed. Different types of modern shearing machines are documented. The ways of ensuring the optimal functionality of the shearing machine and how the shearing operation has improved the manufacturing products were scripted. Three cases were given on the recent advancement in the use of shearing operation. Recommendations on how to improve efficiency in shearing metal forming are specified with relevance to the theory and a conclusion is drawn.

scholarly journals Russia’s Foreign Policy Evolution in the New Balkan Landscape

2020 ◽  
Vol 56 (3-4) ◽  
pp. 179-199
Author(s):  
Ekaterina Entina ◽  
Alexander Pivovarenko
Keyword(s):  
Foreign Policy ◽  
Soviet Union ◽  
Regional Security ◽  
Southeast Europe ◽  
The Balkans ◽  
Current Trends ◽  
The Soviet Union ◽  
Recent Developments ◽  
The Difference

The article reflects on the issue of the foreign policy strategy of modern Russia in the Balkans region. One of the most significant aspects of this problem is the difference in views between Russia and the West. Authors show how different interpretations of the events in former Yugoslavia in the 1990s and the beginning of the 2000s predetermined the sense of mutual suspicion and mistrust which spread to other regions such as the post-Soviet space. Exploring differences between the Russian and the Western (Euro-Atlantic) views on the current matters, authors draw attention to fundamental differences in terminology: while the Western narrative promotes more narrow geographical and political definitions (such as the Western Balkan Six), traditional Russian experts are more inclined to wider or integral definitions such as “the Balkans” and “Central and Southeast Europe”. Meanwhile none of these terms are applicable for analysis of the current trends such as the growing transit role of the Balkans region and its embedding in the European regional security architecture. Therefore, a new definition is needed to overcome the differences in vision and better understand significant recent developments in the region. Conceptualizing major foreign policy events in Central and Southeast Europe during the last three decades (the 1990s, 2000s and 2010s), authors demonstrate the significance of differences in tools and methods between the Soviet Union and the modern Russia. Permanent need for adaptation to changing political and security context led to inconsistence in Russian Balkan policy in the 1990s. Nevertheless, Russia was able to preserve an integral vision of the region and even to elaborate new transregional constructive projects, which in right political circumstances may promote stability and become beneficial for both Russia and the Euro-Atlantic community.

scholarly journals Cardiac Organoids to Model and Heal Heart Failure and Cardiomyopathies

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 563
Author(s):  
Magali Seguret ◽  
Eva Vermersch ◽  
Charlène Jouve ◽  
Jean-Sébastien Hulot
Keyword(s):  
Tissue Engineering ◽  
Drug Testing ◽  
Cardiac Tissue ◽  
Cardiac Tissue Engineering ◽  
Cardiac Cells ◽  
Cardiac Functions ◽  
Different Types ◽  
Recent Developments ◽  
Human Cardiac Tissue ◽  
Key Aspects

Cardiac tissue engineering aims at creating contractile structures that can optimally reproduce the features of human cardiac tissue. These constructs are becoming valuable tools to model some of the cardiac functions, to set preclinical platforms for drug testing, or to alternatively be used as therapies for cardiac repair approaches. Most of the recent developments in cardiac tissue engineering have been made possible by important advances regarding the efficient generation of cardiac cells from pluripotent stem cells and the use of novel biomaterials and microfabrication methods. Different combinations of cells, biomaterials, scaffolds, and geometries are however possible, which results in different types of structures with gradual complexities and abilities to mimic the native cardiac tissue. Here, we intend to cover key aspects of tissue engineering applied to cardiology and the consequent development of cardiac organoids. This review presents various facets of the construction of human cardiac 3D constructs, from the choice of the components to their patterning, the final geometry of generated tissues, and the subsequent readouts and applications to model and treat cardiac diseases.

scholarly journals Variational Problems with Time Delay and Higher-Order Distributed-Order Fractional Derivatives with Arbitrary Kernels

Mathematics ◽  
2021 ◽  
Vol 9 (14) ◽  
pp. 1665
Author(s):  
Fátima Cruz ◽  
Ricardo Almeida ◽  
Natália Martins
Keyword(s):  
Time Delay ◽  
Fractional Derivatives ◽  
Variational Problems ◽  
Higher Order ◽  
Sufficient Optimality Conditions ◽  
Fractional Operator ◽  
Different Types ◽  
Generalized Fractional Derivatives ◽  
Necessary And Sufficient ◽  
Distributed Order

In this work, we study variational problems with time delay and higher-order distributed-order fractional derivatives dealing with a new fractional operator. This fractional derivative combines two known operators: distributed-order derivatives and derivatives with respect to another function. The main results of this paper are necessary and sufficient optimality conditions for different types of variational problems. Since we are dealing with generalized fractional derivatives, from this work, some well-known results can be obtained as particular cases.

scholarly journals Introduction to the Special Issue “Radiative Transfer in the Earth Atmosphere”

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 479
Author(s):  
Irina Sokolik
Keyword(s):  
Radiative Transfer ◽  
Earth Atmosphere ◽  
Special Issue ◽  
The Earth ◽  
Radiative Impact ◽  
Different Types ◽  
Recent Developments

This Special Issue aims at addressing the recent developments towards improving our understanding of the diverse radiative impact of different types of aerosols and clouds [...]

scholarly journals Spin-ice physics in cadmium cyanide

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chloe S. Coates ◽  
Mia Baise ◽  
Adrian Schmutzler ◽  
Arkadiy Simonov ◽  
Joshua W. Makepeace ◽  
...  
Keyword(s):  
Dipole Moments ◽  
Interaction Strength ◽  
Magnetic Interaction ◽  
Energy Scale ◽  
Spin Ice ◽  
Structural Behaviour ◽  
Geometric Frustration ◽  
Cadmium Cyanide ◽  
The Difference ◽  
Increased Strength

AbstractSpin-ices are frustrated magnets that support a particularly rich variety of emergent physics. Typically, it is the interplay of magnetic dipole interactions, spin anisotropy, and geometric frustration on the pyrochlore lattice that drives spin-ice formation. The relevant physics occurs at temperatures commensurate with the magnetic interaction strength, which for most systems is 1–5 K. Here, we show that non-magnetic cadmium cyanide, Cd(CN)2, exhibits analogous behaviour to magnetic spin-ices, but does so on a temperature scale that is nearly two orders of magnitude greater. The electric dipole moments of cyanide ions in Cd(CN)2 assume the role of magnetic pseudospins, with the difference in energy scale reflecting the increased strength of electric vs magnetic dipolar interactions. As a result, spin-ice physics influences the structural behaviour of Cd(CN)2 even at room temperature.

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