Search results for "SIP"
showing 10 items of 1280 documents
Imaging standing surface plasmons by photon tunneling
2005
We present a direct method for optically exciting and imaging delocalized standing surface plasmons in thin metal films. We show theoretically that when imaging the field of the plasmons with a photon scanning tunneling microscope, the presence of the dielectric probe has a negligible effect on the surface modes of the metal film. We demonstrate that plasmon interference can be sustained in arbitrarily large regions of the metal film in comparison to the excitation wavelength. This knowledge can be important when seeking the relative distance between two scattering centers such as the presence of micron or submicron structures.
Progress in the characterization of insulin-like peptides in aphids: Immunohistochemical mapping of ILP4.
2021
Aphids were the first animals described as photoperiodic due to their seasonal switch from viviparous parthenogenesis to sexual reproduction (cyclical parthenogenesis) caused by the shortening of the photoperiod in autumn. This switch produces a single sexual generation of oviparous females and males that mate and lay diapausing cold-resistant eggs that can overcome the unfavourable environmental conditions typical of winter in temperate regions. Previous studies have hinted at a possible implication of two insulin-like peptides (ILP1 and ILP4) in the aphid seasonal response, changing their expression levels between different photoperiodic conditions. Moreover, in situ localization of their…
Komposisi Kimia Cacing Kacang (Sipunculus nudus) di Kabupaten Raja Ampat dan Kabupaten Manokwari
2017
Filum Sipuncula adalah biota laut unik, dari penampilan luarnya. Hewan ini mirip dengan cacing, sehingga diistilahkan peanut worm. Masyarakat pesisir Papua khususnya di Papua Barat telah memanfaatkan organisme ini sebagai bahan pangan, tetapi komposisi gizi dari spesies inu belum banyak dibahas. Penelitian dilakukan Maret-April 2014, bertujuan untuk mengetahui komposisi kimia dari Sipuncula nudus yang diambil dari perairan Raja Ampat dan Manokwari. Hasil menunjukkan bahwa kadar air S. nudus dari Kelurahan Sowi 4 Manokwari) yaitu 8.06%, kadar lemak tertinggi terdapat pada Kampung Amdui Raja Ampat) yaitu 1.70%, kadar protein tertinggi berasal dari Kampung Amdui Raja Ampat) yaitu 82.46%, karbo…
Stochastic seismic analysis of hydrodynamic pressure in dam reservoir systems
2002
Hydrodynamic seismic-induced pressure requires careful consideration in the aseismic design of dams. Effects induced by earthquake excitation may cause many-fold increments of hydrostatic pressure. In this study earthquake excitation has been modelled by means of random process theory obtaining the response statistics of a dam-reservoir dynamical system. The analysis has been conducted assuming a rigid retaining wall of the reservoir and dissipative fluid. Copyright © 2002 John Wiley & Sons, Ltd.
Electrical excitation of surface plasmons
2011
We exploit a plasmon mediated two-step momentum down-conversion scheme to convert low-energy tunneling electrons into propagating photons. Surface plasmon polaritons (SPPs) propagating along an extended gold nanowire are excited on one end by low-energy electron tunneling and are then converted to free-propagating photons at the other end. The separation of excitation and outcoupling proves that tunneling electrons excite gap plasmons that subsequently couple to propagating plasmons. Our work shows that electron tunneling provides a nonoptical, voltage-controlled, and low-energy pathway for launching SPPs in nanostructures, such as plasmonic waveguides.
A 1D coupled Schrödinger drift-diffusion model including collisions
2005
We consider a one-dimensional coupled stationary Schroedinger drift-diffusion model for quantum semiconductor device simulations. The device domain is decomposed into a part with large quantum effects (quantum zone) and a part where quantum effects are negligible (classical zone). We give boundary conditions at the classic-quantum interface which are current preserving. Collisions within the quantum zone are introduced via a Pauli master equation. To illustrate the validity we apply the model to three resonant tunneling diodes.
Influence of dissipative tunneling on the photodielectric effect associated with the excitation of impurity complexes A+ + e in a quasi-zero-dimensio…
2022
Effect of tunneling decay for the quasi-stationary A+-state, in an impurity complex A+ + e (a hole, localized on a neutral acceptor, interacting with an electron, localized in the ground state of a quantum dot) on the photodielectric effect, associated with the excitation of impurity complexes A+ + e in a quasi-zero-dimensional structure, has been studied in the zero-radius potential model in the one-instanton approximation. Calculation of the binding energy of a hole in an impurity complex A+ + e was performed in the zero radius potential model in the adiabatic approximation. It is shown that as the probability of dissipative tunneling increases, the binding energy of a hole in a complex A…
Local Quench, Majorana Zero Modes, and Disturbance Propagation in the Ising chain
2016
We study the generation and propagation of local perturbations in a quantum many-body spin system. In particular, we study the Ising model in transverse field in the presence of a local field defect at one edge. This system possesses a rich phase diagram with different regions characterized by the presence of one or two Majorana zero modes. We show that their localized character {\it i}) enables a characterization of the Ising phase transition through a local-only measurement performed on the edge spin, and {\it ii}) strongly affects the propagation of quasiparticles emitted after the sudden removal of the defect, so that the dynamics of the local magnetization show clear deviations from a …
Composite quantum collision models
2017
A collision model (CM) is a framework to describe open quantum dynamics. In its {\it memoryless} version, it models the reservoir $\mathcal R$ as consisting of a large collection of elementary ancillas: the dynamics of the open system $\mathcal{S}$ results from successive "collisions" of $\mathcal{S}$ with the ancillas of $\mathcal R$. Here, we present a general formulation of memoryless {\it composite} CMs, where $\mathcal S$ is partitioned into the very open system under study $S$ coupled to one or more auxiliary systems $\{S_i\}$. Their composite dynamics occurs through internal $S$-$\{S_i\}$ collisions interspersed with external ones involving $\{S_i\}$ and the reservoir $\mathcal R$. W…
Stringlike Cooperative Motion in a Supercooled Liquid
1998
Extensive molecular dynamics simulations are performed on a glass-forming Lennard-Jones mixture to determine the nature of the cooperative motions occurring in this model fragile liquid. We observe stringlike cooperative molecular motion (``strings'') at temperatures well above the glass transition. The mean length of the strings increases upon cooling, and the string length distribution is found to be nearly exponential.