The growing development of interactive energy systems has motivated a regional energy service company (ESCO) to build energy hubs (EH) that play a substantial role in the coupling of various energy carriers. EH configuration optimization is critical to the economic operation of an ESCO. Therefore, this study proposes a configuration and sizing model that considers the integrated demand response (IDR) to optimize the size of the infrastructures in an EH, and hence minimize the total cost. The EH, which is composed of converters and storage units, is modelled in the matrix form, wherein the operation constraints are expressed in detail. Subsequently, an IDR program based on both responsive thermal and electrical loads is innovatively incorporated into the optimization model, and its effects on EH planning were investigated. By considering several cases: (i) we confirm the effectiveness of the IDR in terms of both cost and capacity reduction on components in the EH; (ii) we show the limited impact of the IDR on the investment cost and equipment configuration, primarily owing to constraints on the maximal total number of dispatching hours; (iii) we observe variations in the impact degree on infrastructure capacity, based on several factors including load characteristics and the electricity–gas price ratio. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

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Raman spectra of three bulk 4H-SiC wafers with different free carrier concentration were measured at temperature from 80 K to 873 K. As temperature increases, Raman peaks of most optical phonon modes show monotonous down shift. An anomalous non-monotonous variation with temperature, was observed in the A(1) longitudinal optical (LO) mode from doped samples. Two methods of theoretical fitting, one-mode (LO-plasma coupled (LOPC) mode) and two-mode (A(1)(LO) + LOPC) fitting, are employed to analyze this anomalous phenomenon. Theoretical simulations for temperature dependent Raman spectra by using two methods are critically examined. It turns out that one-mode method conforms well the experimental results, while two-mode method is untenable in physics. The non-monotonous variation of blue-red shifts with temperature for LOPC mode from doped 4H-SiC could be explained by the influence from ionization process of impurities on the process of Raman scattering. A quantitative description on temperature dependent Raman spectra for doped 4H-SiC is achieved, which matches well to experimental data.

Synchrotron radiation X-ray absorption and UV 325 nm excitation Raman scattering- photoluminescence (PL) have been employed to investigate a series of 4H-SiC wafers, including bulk, epitaxial single or multiple layer structures by chemical vapor deposition. Significant results on the atomic bonding and PL-Raman properties are obtained from these comparative studies.

Optical properties and carrier dynamics of InGaN/GaN asymmetric coupled quantum wells (ACQWs) are studied by excitation-power-dependent photoluminescence (PL), photoreflectance (PR) and time-resolved PL (TRPL) experiments. Under weak excitations, only the emission from the widest well is observed due to the tunneling from narrower to wider wells. Under strong excitations, the carrier distribution becomes more uniform and an enhanced emission from the mid well (2.5 nm well) is observed. Dependence of the PL intensity on excitation power is well explained by a rate equation model. The energy levels in the ACQW structure are clearly revealed by PR measurements and are in good agreement with calculations. Our results indicate that the enhanced emission from the mid well is ascribed to "reverse tunneling" from 3.0 to 2.5 nm well, which is confirmed by TRPL experiments.