Kink plateau dynamics in finite-size lubricant chains

We extend the study of velocity quantization phenomena recently found in the classical motion of an idealized 1D model solid lubricant -- consisting of a harmonic chain interposed between two periodic sliding potentials [Phys. Rev. Lett. 97, 056101 (2006)]. This quantization is due to one slider rigidly dragging the commensurate lattice of kinks that the chain forms with the other slider. In this follow-up work we consider finite-size chains rather than infinite chains. The finite size (i) permits the development of robust velocity plateaus as a function of the lubricant stiffness, and (ii) allows an overall chain-length re-adjustment which spontaneously promotes single-particle periodic oscillations. These periodic oscillations replace the quasi-periodic motion produced by general incommensurate periods of the sliders and the lubricant in the infinite-size model. Possible consequences of these results for some real systems are discussed.Comment: 12 pages, 5 figures, ECOSS 200

Stability of Periodic, Traveling-Wave Solutions to the Capillary-Whitham Equation

Recently, the Whitham and capillary-Whitham equations were shown to accurately model the evolution of surface waves on shallow water. In order to gain a deeper understanding of these equations, we compute periodic, traveling-wave solutions to both and study their stability. We present plots of a representative sampling of solutions for a range of wavelengths, wave speeds, wave heights, and surface tension values. Finally, we discuss the role these parameters play in the stability of the solutions

Channel characterisation of cooperative relaying power line communication systems

© 2016 IEEE. Power line communication (PLC) technology offers a promising platform for numerous communication applications. The power lines however can significantly attenuate communication signals operating in high frequency band. For this reason, multi-hop PLC systems become desirable. In this paper, we investigates the effect of multi-hop relaying on the power line channel transfer function. Measured results are compared with results obtained from sumulations in Matlab. Results show that the presence of relays between a transmitting and a receiving PLC nodes can intensify the attenuation and frequency selectivity. Measurements show that maximum attenuation increases with number of relays

Turning the six-party talks into a multilateral security framework for Northeast Asia

행사명 : Academic Symposiu

Quantum Frenkel-Kontorova Model

This paper gives a review of our recent work on the quantum Frenkel-Kontorova model. Using the squeezed state theory and the quantum Monte Carlo method, we have studied the effects of quantum fluctuations on the Aubry transition and the behavior of the ground state wave function. We found that quantum fluctuations renormalize the sinusoidal standard map to a sawtooth map. Although quantum fluctuations have smeared the Aubry transition, the remnants of this transition are still discernible. The ground state wave function also changes from an extended state to a localized state. The squeezed state results agree very well with those from the Monte Carlo and mean field studies.Comment: 20 pages in elsart.sty, 11 eps figure

Present state of investment casting technology - application in practice

Tato bakalářská práce si klade za cíl shromáždit základní informace o současném uplatnění odlitků vyrobených metodou vytavitelného modelu. Je zaměřena na využití těchto odlitků v různých odvětvích průmyslu a na mate-riálu používaném při jejich výrobě. Dále se tato práce zaobírá množstvím těchto odlitků a procentuelním rozpoložením ve světovém i domácím prodeji.This bachelor thesis proposes to collect basic information regarding existing usage of castings produced by smelting model method. The work is focused on usage of these castings at different industrial branches and ma-terial used at manufacturing of these castings. The work is also engaged in quantity of these castings and percentage share in worldwide and domestic market.

Strategic Triangles Reshaping International Relations in East Asia

Rozman shows how East Asia’s international relations over three decades can be best understood through the lens of triangles, analyzing relations between the key nations through a series of trilateral relationships. He argues that triangles present a convincing answer to the question of whether we had entered a new era of bipolarity like the Cold War or an age of multipolarity. Triangulation emerged as a dynamic in East Asia in the aftermath of the Cold War and was accelerated in the course of the Xi and Trump administrations. Even as Sino-US competition and confrontation deepened, triangles had a substantial presence. East Asian triangles share an unusual mixture of three distinct elements: deep-seated security distrust, extraordinary economic interdependence, and a combustible composition of historical resentments and civilizational confidence. The combination of the three makes the case for triangularity more compelling, Rozman argues. The legacy of communism, the pursuit of reunification on the Korean Peninsula, and moves to expand beyond the US-Japan alliance have all driven the way triangles have evolved. Only as bipolarity intensified in the 2020s was triangularity losing ground. The degree of turnabout is analyzed for all of the cases considered. Rozman evaluates each key triangle of states in turn and assesses how the relationship impacts the region more widely. This book provides an essential framework for understanding the current state and trajectory of East Asian international relations, for students and policymakers