Distributed entanglement induced by dissipative bosonic media

We describe a scheme with analytic result that allows to generate steady-state entanglement for two atoms over a dissipative bosonic medium. The resonant coupling between the mediating bosonic mode and cavity modes produces three collective atomic decay channels. This dissipative dynamics, together with the unitary process induced by classical microwave fields, drives the two atoms to the symmetric or asymmetric entangled steady state conditional upon the choice of the phases of the microwave fields. The effects on the steady-state entanglement of off-resonance mediating bosonic modes are analyzed. The entanglement can be obtained with high fidelity regardless of the initial state and there is a linear relation in the scaling of the fidelity with the cooperativity parameter. The fidelity is insensitive to the fluctuation of the Rabi frequencies of the classical driving fields.Comment: to appear in Europhysics Letter

Tunable-Focus Liquid Lens through Charge Injection

Liquid lenses are the simplest and cheapest optical lenses, and various studies have been conducted to develop tunable-focus liquid lenses. In this study, a simple and easily implemented method for achieving tunable-focus liquid lenses was proposed and experimentally validated. In this method, charges induced by a corona discharge in the air were injected into dielectric liquid, resulting in “electropressure” at the interface between the air and the liquid. Through a 3D-printed U-tube structure, a tunable-focus liquid lens was fabricated and tested. Depending on the voltage, the focus of the liquid lens can be adjusted in large ranges (−∞ to −9 mm and 13.11 mm to ∞). The results will inspire various new liquid-lens applications

Plasma-induced unconventional shock waves on oil surfaces

Electric corona discharge in a multi-phase system results in complex electro-hydrodynamic phenomena. We observed unconventional shock wave propagation on an oil thin film sprayed over a polymer-coated conductor. A hair-thin single shock wave arose when the high voltage bias of an overhung steel needle was abruptly removed. However, such solitary waves possess neither interference nor reflection properties commonly known for ordinary waves, and also differ from the solitons in a canal or an optical fiber. We also observed time-retarded movement for dispersed oil droplets at various distances from the epicenter which have no physical contact, as if a wave propagating on a continuous medium. Such a causality phenomenon for noncontact droplets to move resembling wave propagation could not be possibly described by the conventional surface wave equation. Our systematic studies reveal a mechanism involving oil surface charges driven by reminiscent electric fields in the air when the needle bias is suddenly removed

Resistência a Corrosão dos Aços Inoxidáveis em Soluções Contendo Íons Cloreto e Piridina Ou Benzimidazol Como Inibidores de Corrosão

A corrosão dos aços inoxidáveis AISI 304 e AISI 430 foi investigada em uma solução de NaCl 3% em massa na ausência e presença dos inibidores piridina ou benzimidazol. O estudo eletroquímico foi realizado utilizando a técnica de polarização potenciodinâmica e Espectroscopia de Impedância Eletroquímica (EIE), a morfologia da superfície dos eletrodos foi caracterizada utilizando as técnicas: Microscopia de Força Atômica (MFA), Microscopia Eletrônica de Varredura (MEV) e, as composições foram investigadas pela análise de EDX (Energia Dispersiva de Raios-X) e Espectrometria de Emissão de Plasma Induzido por Laser (LIBS). Os resultados obtidos pelas curvas de polarização mostraram que o aço inoxidável AISI 304 é mais resistente a corrosão que o aço inoxidável AISI 430. A eficiência de inibição foi avaliada em seis concentrações diferentes (5 ppm , 25 ppm , 50 ppm , 100 ppm , 500 ppm e 1000 ppm) para cada um dos inibidores, e em todas as concentrações foram observados um aumento do potencial de corrosão. As medidas de MFA mostraram que os valores de profundidade dos pites foram pelo menos 4 vezes menor do que os valores obtidos na ausência da piridina como inibidor para ambas as ligas. No caso do benzimidazol como inibidor, os valores obtidos de profundidade dos pites foram, pelo menos, 8 vezes inferior

Directional motion of dielectric droplets on polymer-coated conductor driven by electric corona discharge

Achieving better control of liquid droplet movement is an important subject for academic research and industrial applications. In this study, we investigate the use of electric corona discharge to drive and control oil droplet movement. For a fully covered polymer-coated copper plate, all droplets on the surface were found to move outward in the same direction. Interestingly, for a polymer coating a hole directly beneath a needle biased with a high DC voltage, we observed the existence of a zone boundary at which all of the droplets within the boundary move inward, whereas droplets outside the boundary move outward. The boundary appeared to depend on the hole size and the voltage bias. Our model simulations reasonably agree well with the experimental measurements of these peculiar phenomena