Design of Wideband Microwave Absorbers Using Reactive Salisbury Screens with Maximum Flat Reflection

This paper presents a design methodology for wideband single-layered microwave absorbers with arbitrary absorption at the design center frequency using reactive Salisbury screens. The bandwidth of the absorber increases when the flatness of the reflection response at the design center frequency is maximized. Based on this observation, closed-form design formulas for wideband absorbers are derived. As they are scalable to any design frequency, wideband reactive screens can be systematically realized using two-dimensional periodic crossed-dipole structures patterned on a resistive sheet. Based on this method, a single-layered absorber with a 90% bandwidth improved to 124% of the design center frequency is presented. For the purpose of physical demonstration, an absorber with a design center frequency of 10 GHz is designed and fabricated using a silver nanowire resistive film with a surface resistance of 30 Ω/square. The measured absorption shows a good agreement with both the calculation and the electromagnetic simulation

Electron Heat Flow Due to Magnetic Field Fluctuations

Radial heat transport induced by magnetic field line fluctuations is obtained from the integral parallel heat flow closure for arbitrary collisionality. The parallel heat flow and its radial component are computed for a single harmonic sinusoidal field line perturbation. In the collisional and collisionless limits, averaging the heat flow over an unperturbed surface yields Rechester-Rosenbluth like formulae with quantitative factors. The single harmonic result is generalized to multiple harmonics given a spectrum of small magnetic perturbations. In the collisionless limit, the heat and particle transport relations are also derived. © 2016 IOP Publishing Ltd

Tailoring ionic structures in Locally concentrated ionic liquid electrolytes for safe, stable cycling of high-voltage Li metal batteries

High voltage Li metal batteries, Locally concentrated ionic liquid electrolyte, Solvation structure, Solid electrolyte interphaseⅠ. Introduction 1.1 Basic principles of Li secondary batteries 1 1.2. Li-metal Battery 2 1.2.1 Merits of Li-metal anode 2 1.2.2 Challenges of Li-metal Anode 3 1.2.3 Evaluation of Li reversibility 4 1.2.4 Effects of cell parameters and operation conditions 6 1.3 Electrolyte System 7 1.3.1 Basic Concepts of Solvation Chemistry 7 1.3.2 Molecular Dynamics 8 1.3.3 Raman spectroscopy 9 1.4 Electrode-Electrolyte Interphase 10 1.4.1 Solid-Electrolyte Interphase (SEI) 10 1.4.2 Cathode-Electrolyte interphase (CEI) 11 1.5. Research Goals 12 Ⅱ. Experimental Method 2.1. Preparation of Electrode and Electrolytes 14 2.2. Electrochemical measurements 14 2.3. Characterizations 15 Ⅲ. Results and discussion 3.1 Designing LCIL (dilution effects of LCIL) 17 3.2 Ionic liquid’s cation effects in LCIL 29 3.3 Additives in LCIL 36 IV. Concluding Remark 39 References 40 Summary in Korean 46MasterdCollectio

ACTIVE DSRC APPLICATION FOR ITS AND ECONOMIC VALUATION IN KOREA

Providing real time traffic information is a key for effective implementation of Intelligent Transport Systems (ITS). The main purpose of this paper is to introduce the recent technological trends of Dedicated Short Range Communications (DSRC) applications for ITS and its economic evaluation, focusing on the City Bus Information System (CBIS) and Electronic Toll Collection System (ETC) in Korea. From a research perspective, it is necessary for the seamless development and maintenance of technical and competitive edges, and the proper budgetary allocation for research and development. Furthermore, the progressive participation of private companies that have the leading technologies on active DSRC is also required.

Control of Power Distribution for Multiple Receivers in SIMO Wireless Power Transfer System

A method to control the power distribution among receivers by the load values in a single-input, multiple-output (SIMO) wireless power transfer (WPT) system is investigated. We first derive the value of loads to maximize total efficiency. Next, a simple, but effective analytical formula of the load condition for the desired power distribution ratio is presented. The derived load solutions are simply given by system figure of merits and desired power ratios. The formula is validated with many numerical examples via electromagnetic simulations. We demonstrate that with the choice of loads from this simple formula, the power can be conveniently and accurately distributed among receivers for most practical requirements in SIMO WPT systems

Towards Personal Financial Sustainability Based on Human Capital Analysis in Korea

Financial sustainability for individuals has become more important due to the increase in life expectancy. In personalized lifetime financial planning, human capital is critical for incorporating the life-cycle of individuals. This study focuses on human capital modeling based on features such as education level and working industry, and presents how difference in human capital can affect the optimal asset allocation. By analyzing the Korean labor and income panel survey data, fixed effects regression was performed to model human capital and a portfolio model that maximizes utility of total wealth is solved to optimize the lifetime financial plan. The empirical results show that individuals with human capital that are more correlated with stocks are advised to reduce allocation in stocks

Towards Personal Financial Sustainability Based on Human Capital Analysis in Korea

Financial sustainability for individuals has become more important due to the increase in life expectancy. In personalized lifetime financial planning, human capital is critical for incorporating the life-cycle of individuals. This study focuses on human capital modeling based on features such as education level and working industry, and presents how difference in human capital can affect the optimal asset allocation. By analyzing the Korean labor and income panel survey data, fixed effects regression was performed to model human capital and a portfolio model that maximizes utility of total wealth is solved to optimize the lifetime financial plan. The empirical results show that individuals with human capital that are more correlated with stocks are advised to reduce allocation in stocks