1,276 research outputs found
Magnetic hyperbolic metamaterial of high-index nanowires
No full textWe show that the axial component of the magnetic permeability tensor is resonant for a wire medium consisting of high-index epsilon-positive nanowires, and its real part changes the sign at a certain frequency. At this frequency the medium experiences the topological phase transition between the elliptic and hyperbolic type of dispersion. We show that the transition regime is characterized by an extremely strong dependence of the permeability on the wave vector. This implies very high density of electromagnetic states that results in the filamentary pattern and noticeable Purcell factor for a transversely oriented magnetic dipole.Peer reviewe
THz Multiple-Beam Manipulation by Reconfigurable Intelligent Surface with Independent Phase/Amplitude Control
No full text| openaire: EC/H2020/956256/EU//META WIRELESStOur paper presents a real-time design using a digital metasurface that can control both the amplitude and phase of reflected waves. Our suggested based metasurface effectively manipulates both transverse electric (TE) and transverse magnetic (TM) reflected waves independently with angular stability up to 40° in the range (1.45-1.55) THz. We anticipate that such metasurfaces may be a good candidate for indoor wireless communication.Peer reviewe
Binary Reconfigurable Intelligent Surfaces with Angle-Independent Reflection Phase
No full textIn this presentation we investigate the use of physical optics (PO) approximation in the design of binary reconfigurable intelligent surfaces (RISs). We show that PO may be used to design and study RIS operating in a wide sheer of incidence and deviation angles if the reflection phase is angularly stable for uniform settings of the RIS array realizing both required phase shifts of reflected plane waves.Peer reviewe
La politica della legalità : il ruolo del giurista nell'età contemporanea
No full textAs the author of this book shows as he tests his theses, impartiality and justice require specific and scrupulous forms of civil engagement which render obsolete the traditional call for neutrality. At the same time, citizens must be made to understand how formal features of law that usually evoke their hostility actually guarantee their rights. The legal professional must learn to be a "relativist", obliged - through his choices - to establish priorities among distinct and often irreconcilable value domains
Effective-medium model of wire metamaterials in the problems of radiative heat transfer
No full textPeer reviewe
Cercando di dimenticare Savigny
No full textIl presente scritto è un contributo alla discussione del libro di Aurelio Gentili, Il
diritto come discorso del 2013. Del predetto volume si approvano senza riserve
a) la critica alla concezione del vecchio positivismo, secondo il quale il giurista
non farebbe altro che esplorare un misterioso oggetto denominato “realtà
giuridica”, e b) l’interesse per le tecniche argomentative quali strumenti di
controllo interno dei discorsi. Sul piano propositivo, l’autore della recensione
ammette che la conoscenza dei significati normativi letterali, quando la si
ritiene rilevante, comporta a livello collettivo (ma assai meno al livello dei
singoli) un giudizio partecipante. Tali significati, del resto, lungi dall’essere
entità fisse, sono sempre in movimento. Ciò stabilito e con questi limiti,
occorre ammettere che non c’è solo un ordo ordinans imposto dai giuristi sui
confusi materiali estratti dalle fonti, ma si può scorgere, e si deve ritrovare,
anche un ordo ordinatus, frutto tanto dell’attività legislativa quanto delle precedenti interpretazioni, che il singolo interprete non può far a meno di
riconoscere. Insomma: tra i due ordini, fra le attività dei giuristi e i prodotti di
tali attività, si stabilisce un rapporto dialettico.This article is a contribution to the discussion regarding Aurelio Gentili’s 2013
book Il diritto come discorso. From the said volume, the author fully approves:
a) the criticism of the old positivism’s conception that a lawyer does nothing
but explore the misterious object that is “legal reality”, and b) the interest in
argumentative techniques as instruments for internal control of discourses. The
author of this article proposes admitting that the knowledge of literal normative
meanings, when believed to be relevant, requires at the level of the collective
(much less so at the individual level) a judgment, which demonstrates
participation. These meanings are, moreover, far from being fixed entities,
always changing. Within these limits, it should be admitted that there is not
only an ordo ordinans, made by the jurists, using the confused materials
extracted from the sources, but that we may also observe, and must rediscover,
an ordo ordinatus, which results from both legislative activity and previous
interpretations – that an individual interpreter cannot but recognize. In short, a
dialectic relationship between the two orders, between the activity of lawyers
and the products of these activities, is thus established
Exact two-dimensionalization of low-magnetic-Reynolds-number flows subject to a strong magnetic field
No full textWe investigate the behavior of flows, including turbulent flows, driven by a horizontal body-force and subject to a vertical magnetic field, with the following question in mind: for very strong applied magnetic field, is the flow mostly two-dimensional, with remaining weak three-dimensional fluctuations, or does it become exactly 2D, with no dependence along the vertical? We restrict attention to low-magnetic-Reynolds number (Rm) flow. Because liquid metals have low magnetic Prandtl number, such low- flows can have a kinetic Reynolds number as large as one million and therefore be strongly turbulent. We first focus on the quasi-static approximation, i.e. the asymptotic limit of vanishing magnetic Reynolds number Rm << 1: we prove that the flow becomes exactly 2D asymptotically in time, regardless of the initial condition and provided the interaction parameter N is larger than a threshold value. We call this property absolute two-dimensionalization: the attractor of the system is necessarily a (possibly turbulent) 2D flow. We then consider the full-magnetohydrodynamic equations and we prove that, for low enough Rm and large enough N, the flow becomes exactly two-dimensional in the long-time limit provided the initial vertically-dependent perturbations are infinitesimal. We call this phenomenon linear two-dimensionalization: the (possibly turbulent) 2D flow is an attractor of the dynamics, but it is not necessarily the only attractor of the system. Some 3D attractors may also exist and be attained for strong enough initial 3D perturbations. These results shed some light on the existence of a dissipative anomaly for magnetohydrodynamic flows subject to a strong external magnetic field
Perfect magnetic mirror and simple perfect absorber in the visible spectrum
No full textKnown experimental artificial magnetic conductors for terahertz and optical frequencies are formed by arrays of nanoparticles of various shapes. In this paper, we show that artificial magnetic conductors for the visible spectrum can be realized as simple, effectively quasistatic resonating structures, where the effective inductance is due to the magnetic flux inside a uniform metal substrate, and the effective capacitance is due to electric polarization of a thin uniform dielectric cover. To illustrate the main potential application of artificial magnetic conductors, we concentrate on the perfect-absorption regime, achieved by adjusting the loss factor of the artificial magnetic conductor to match its real input impedance to free space. We provide approximate analytical design formulas and introduce a simple equivalent circuit to explain the physical mechanism of emulation of magnetic response and perfect absorption of light. A prototype of a nearly perfect absorber for optical (from green to ultraviolet) frequencies is designed and experimentally tested. The results confirm the theoretical predictions and show polarization insensitivity and angular independence of response in a wide range of incidence angles.Peer reviewe
Letter from Lee C.R. Baker, Reference Assistant to Michi Weglyn, September 25, 1974
No full textThis letter refers to a thesis written by Warren Page Rucker in 1970 entitled, "United States--Peruvian Policy Toward Peruvian-Japanese Persons During World War II." Baker explains that Weglyn can purchase a copy of the thesis if she so desires.Collection of notes, articles, correspondence, photographs, and term papers collected by Yukio Mochizuki, a student at CSU Dominguez Hills, while researching Japanese American incarceration and Japanese Peruvian internment during World War II
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