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With increasing demand for energy, the penetration of alternative sources such as renewable energy in power grids has increased. Solar energy is one of the most common and well-known sources of energy in existing networks. But because of its non-stationary and non-linear characteristics, it needs to predict solar irradiance to provide more reliable Photovoltaic (PV) plants and manage the power of supply and demand. Although there are various methods to predict the solar irradiance. This paper gives the overview of recent studies with focus on solar irradiance forecasting with ensemble methods which are divided into two main categories: competitive and cooperative ensemble forecasting. In addition, parameter diversity and data diversity are considered as competitive ensemble forecasting and also preprocessing and post-processing are as cooperative ensemble forecasting. All these ensemble forecasting methods are investigated in this study. In the end, the conclusion has been drawn and the recommendations for future studies have been discussed.
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We investigated the localized surface plasmon resonances of individual AgAuAg nanorods (NRs) using the dark-field spectro-microscopy technique. We find that the scattering spectra of such hetero-NRs show longitudinal resonance wavelengths that are nearly insensitive to the relative composition of Ag and Au. Instead, the resonance is mostly governed by the overall length of the nanorod. This shows that the plasmons oscillate along the entire length of the NR without the significant perturbation at the Ag-Au interfaces. The results demonstrate that the overall geometry as well as the composition determine the tunability of the hetero-metallic nanostructures, and provide an important design rule for the composition-tunable bimetallic plasmon structures.
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We demonstrate that a single-pulse characterization of electronic optical activity-free induction decay, which carries information on both circular dichroism and optical rotatory dispersion, is experimentally feasible. Employing a self-referencing scheme, we show that a highly reliable interferometric chiroptical measurement free from power and phase fluctuations is achievable on a shot-by-shot basis.
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Intrinsic handedness encountered in molecular sciences plays an essential role in diverse physical, chemical and biological processes. Optical activity spectroscopy has enabled one to characterize such molecular handedness (chirality) and demonstrated its unique ability to provide stereo-specific structural insight into chiral molecular systems including biopolymers, chiral drugs, and superchiral materials. However, more extended applications including time-resolved studies have often been hindered by inherent limitations of conventional differential methods utilizing both left- and right-handed radiations. The latest methodological advance is heterodyned detection methods measuring wave interferences between signal and reference fields, which allowed direct characterizations of coherent chiroptical signals in a flash. With its ultimate sensitivity, the heterodyned chiroptical method promises to open new possibilities of transient electronic or vibrational optical activity measurements in the ultrafast time domain.
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We demonstrate that broadband electronic optical activity can be measured with supercontinuum light pulse generated by a femtosecond pump (800 nm). It is the self-heterodyned detection technique that enables us to selectively measure the real (optical rotatory dispersion, ORD) or imaginary (circular dichroism, CD) part of the chiroptical susceptibility by controlling the incident polarization state. The single-shot-based measurement that is capable of correcting power fluctuations of the continuum light is realized by using a fast CCD detector and a polarizing beam splitter. Particularly, non-differential scheme used does not rely on any polarization-switching components. We anticipate that this broadband CD/ORD spectrometry with intrinsically ultrafast time-resolution will be applied to a variety of ultrafast chiroptical dynamics studies.
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We carried out the near-field optical imaging of isolated and dimerized gold nanocubes to directly investigate the strong coupling between two adjacent nanoparticles. The high-resolution (approximately 10 nm) local field maps (intensities and phases) of self-assembled nanocube dimers reveal antisymmetric plasmon modes that are starkly different from a simple superposition of two monomeric dipole plasmons, which is fully reproduced by the electrodynamics simulations. The result decisively proves that, for the closely spaced pair of nanoparticles (interparticle distance/particle size approximately 0.04), the strong Coulombic attraction between the charges at the interparticle gap dominates over the intraparticle charge oscillations, resulting in a hybridized dimer plasmon mode that is qualitatively different from those expected from a simple dipole-dipole coupling model.
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Scattering-type apertureless near-field microscopy (ANSOM) provides high-resolution dielectric maps of indium gallium nitride (InGaN) semiconductor nanoparticles at visible (633 nm) wavelengths. A specific size-dependent contrast reversal is observed in the ANSOM images of InGaN nanoparticles grown on a layer of gallium nitride (GaN). Model calculations demonstrate that the observed contrast reversal is the result of the competition between the tip-particle versus tip-substrate dipolar coupling.
Asunto(s)
Cristalización/métodos , Microscopía de Fuerza Atómica/métodos , Nanoestructuras/química , Nanoestructuras/ultraestructura , Nanotecnología/métodos , Semiconductores , Impedancia Eléctrica , Sustancias Macromoleculares/química , Ensayo de Materiales/métodos , Conformación Molecular , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
Capillary RPLC/ESI-MS (cRPLC/ESI-MS) is one of the most powerful analytical tools for current proteomic research. The development of cRPLC techniques coupled online to a mass spectrometer has focused on increasing the separation efficiency, detection sensitivity, and throughput. Recently, the use of high-pressure (over 10,000 psi) LC systems that utilize long, small inner diameter capillary columns has gained much attention for proteomic analyses. In this study, we developed an ultrahigh-pressure dual online SPE/capillary RPLC (DO-SPE/cRPLC) system. This LC system employs two online SPE columns and two capillary columns (75 microm inner diameter x 1 m length) in a single separation system, and has a maximum operating pressure of 10,000 psi. This DO-SPE/cRPLC system is capable of providing high-resolution separation in addition to several other advantageous features, such as high reproducibility in terms of the LC retention time, rapid sample injection, online desalting, online sample enrichment of dilute samples, and increased throughput as a result of essentially removing the column equilibration time between successive experiments. We coupled the DO-SPE/cRPLC system online to a tandem mass spectrometer to allow high-throughput proteomic analyses. In this paper, we demonstrate the efficiency of this DO-SPE/cRPLC/MS/MS system by its use in the analyses of proteomic samples exhibiting different levels of complexity.