Nanjing University of Aeronautics and Astronautics

About: Nanjing University of Aeronautics and Astronautics is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Computer science & Microstructure. The organization has 33704 authors who have published 37321 publications receiving 438855 citations. The organization is also known as: Nanjing College of Aviation Industry & Nanjing Aeronautical Institute.

Investigation on the Selection of Electric Power System Architecture for Future More Electric Aircraft

Abstract: This paper identifies the most promising electric power system (EPS) architecture for a future more electric aircraft based on reviews and evaluations of both system weight and stability feature of the existing EPS architectures. When comparing the overall system weight of different architectures, various aspects, including voltage generation, wiring system, ground operation, power conversion, and complexity of integrating alternative energy sources, are considered. After choosing the possible candidates among all the possible architectures by using weight-saving criterion, stability features for the initially selected candidates are further evaluated. Necessary simulation studies are carried out in MATLAB/Simulink to prove the correctness of stability study. Finally, the one both good at weight saving and with the highest stability region is deemed as the most promising EPS architecture for future MEAs.

An Ultrasensitive Silicon Photonic Ion Sensor Enabled by 2D Plasmonic Molybdenum Oxide

Abstract: Silicon photonics has demonstrated great potential in ultrasensitive biochemical sensing. However, it is challenging for such sensors to detect small ions which are also of great importance in many biochemical processes. A silicon photonic ion sensor enabled by an ionic dopant-driven plasmonic material is introduced here. The sensor consists of a microring resonator (MRR) coupled with a 2D restacked layer of near-infrared plasmonic molybdenum oxide. When the 2D plasmonic layer interacts with ions from the environment, a strong change in the refractive index results in a shift in the MRR resonance wavelength and simultaneously the alteration of plasmonic absorption leads to the modulation of MRR transmission power, hence generating dual sensing outputs which is unique to other optical ion sensors. Proof-of-concept via a pH sensing model is demonstrated, showing up to 7 orders improvement in sensitivity per unit area across the range from 1 to 13 compared to those of other optical pH sensors. This platform offers the unique potential for ultrasensitive and robust measurement of changes in ionic environment, generating new modalities for on-chip chemical sensors in the micro/nanoscale.

Trilemma assessment of energy intensity, efficiency, and environmental index: evidence from BRICS countries

Abstract: This paper provides an assessment of energy density and energy efficiency and creates an important indicator of environmental performance. This article applied two mathematical models and econometric techniques to obtain detailed and specific results. The DEA and the non-normative account aggregation mean a collective aggregation to form a mathematical aggregation tool to create an environmental index for the BRICS countries (Brazil, Russia, India, China, and South Africa) based on available data from 2011 to 2016. The advantage of the proposed approach is to manage the irregularities of the data and follow the desired properties of the index number. The current paper is relevant for the broad scope of construction, the environmental index, and the evolution of the rankings of countries based on multiple indicators. Our results indicate that Brazil and Russia have the highest values of the Environmental Performance Index, which range between 67.44 and 60.70, respectively. India has a minimum value of 30.57 of the environmental index. The analysis shows that Brazil, Russia, and South Africa have the best scores and that these countries have the best results, while China and India also have the best results. This study can help form a valuable political tool for the development and development of the country's politics.

An Optimal Control Method for Photovoltaic Grid-Tied-Interleaved Flyback Microinverters to Achieve High Efficiency in Wide Load Range

Abstract: Boundary conduction mode (BCM) and discontinuous conduction mode (DCM) control strategies are widely used for the flyback microinverter. The BCM and DCM control strategies are investigated for the interleaved flyback microinverter concentrating on the loss analysis under different load conditions. These two control strategies have different impact on the loss distribution and thus the efficiency of the flyback microinverter. For the interleaved flyback microinverter, the dominant losses with heavy load include the conduction loss of the power MOSFETs and diodes, and the loss of the transformer; while the dominant losses with light load include the gate driving loss, the turn-off loss of the power MOSFETs and the transformer core loss. Based on the loss analysis, a new hybrid control strategy combing the two-phase DCM and one-phase DCM control is proposed to improve the efficiency in wide load range by reducing the dominant losses depending on the load current. The optimal design method based on the boundary condition of the hybrid control is also presented. The experimental results verify the benefits of the proposed control.

An Ultra-wideband and Polarization-independent Metasurface for RCS Reduction.

Abstract: In this paper, an ultra-wideband and polarization-independent metasurface for radar cross section (RCS) reduction is proposed. The unit cell of the metasurface operates in a linear cross-polarization scheme in a broad band. The phase and amplitude of cross-polarized reflection can be separately controlled by its geometry and rotation angle. Based on the diffuse reflection theory, a 3-bit coding metasurface is designed to reduce the RCS in an ultra-wide band. The wideband property of the metasurface benefits from the wideband cross polarization conversion and flexible phase modulation. In addition, the polarization-independent feature of the metasurface is achieved by tailoring the rotation angle of each element. Both the simulated and measured results demonstrate that the proposed metasurface can reduce the RCS significantly in an ultra-wide frequency band for both normal and oblique incidences, which makes it promising in the applications such as electromagnetic cloaking.