• Journal of Magnetics
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• 제20권3호
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• pp.252-257
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• 2015

This paper investigates the concept and implementation of an energy harvesting device using a ferrofluid sloshing movement to generate an electromotive force (EMF). Ferrofluids are often applied to energy harvesting devices because they have both magnetic properties and fluidity, and they behave similarly to a soft ferromagnetic substance. In addition, a ferrofluid can change its shape freely and generate an EMF from small vibrations. The existing energy harvesting techniques, for example those using piezoelectric and thermoelectric devices, generate minimal electric power, as low as a few micro-watts. Through flow analysis of ferrofluids and examination of the magnetic circuit characteristics of the resultant electromagnetic system, an energy harvester model based on an electromagnetic field generated by a ferrofluid is developed and proposed. The feasibility of the proposed scheme is demonstrated and its EMF characteristics are discussed based on experimental data.

• 한국정밀공학회지
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• 제30권12호
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• pp.1341-1347
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• 2013

Energy harvesting is a clean technology to obtain energy from the surrounding environment such as wind, sun, vibration and so on. In particular, the current TPMS (Tire Pressure Monitoring Device) is very small and attached to the outside of a vehicle and power supply of the TPMS is limited. Therefore, energy harvesting using vibration energy of piezoelectric materials is important to the TPMS. In this paper, we analyzed several models using ANSYS which is one of the FEA (Finite Element Analysis) package and compared corresponding strain frequency response functions of the TPMS. In addition, we confirmed that dynamic characteristics variations according to geometry changes have effects on the performance of the TPMS.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 추계학술발표대회
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• pp.199-201
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• 2016

Wireless sensor networks offer an attractive solution to several environments, security, and process monitoring problems. However, one barrier for their full adoption is the need to provide electrical power over extended periods of time without the need of dedicated wiring. Energy harvesting offers good solutions to this problem in several applications. This paper surveys the energy requirements of typical sensor network nodes and summarizes the future research work in the field of energy harvesting resource allocation in wireless sensor networks.

• Journal of Biosystems Engineering
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• 제13권2호
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• pp.9-17
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• 1988

This study was carried out to develop an agricultural robot for fruit harvesting. As the first step an experimental manipulator and its control system were constructed. The articulated manipulator driven by DC motors has 3 degrees-of-freedom. The manipulator has a gripper adequate for fruit harvesting and an upper arm which forms a kind of guiding channel so thai harvested fruit can pass through. Point-to-point control of joints are accomplished by a digital control system with a PID controller which consists of optical shaft encoders, power amplifiers using PWM, a microcomputer and a software. The microcomputer also computes the positions of manipulator and sequence of motions. The motion of the manipulator was to slow and rough that it would need further improvement.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 추계학술대회
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• pp.425-428
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• 2017

본 논문에서는 진동 에너지를 이용하여 에너지를 수확하는 전파 정류 하베스팅 회로를 설계하였다. 설계된 회로는 저전압에서도 전력효율이 우수하도록 Beta-Multiplier를 이용하여 Body-Bias technique을 Negative Voltage Converter에 적용하였으며, Comparator를 Bulk-Driven type으로 설계하였다. 제안된 회로는 $0.35{\mu}m$ CMOS 공정으로 설계하였으며, 설계된 회로의 칩 면적은 $931{\mu}m{\times}785{\mu}m$이다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.453-454
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• 2007

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.380-381
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• 2012

Bioinspired sea urchin-like structures were fabricated on silicon by inductively coupled plasma (ICP) etching using lens-like shape hexagonally patterned photoresist (PR) patterns and subsequent metal-assisted chemical etching (MaCE) [1]. The lens-like shape PR patterns with a diameter of 2 ${\mu}m$ were formed by conventional lithography method followed by thermal reflow process of PR patterns on a hotplate at $170^{\circ}C$ for 40 s. ICP etching process was carried out in an SF6 plasma ambient using an optimum etching conditions such as radio-frequency power of 50 W, ICP power of 25 W, SF6 flow rate of 30 sccm, process pressure of 10 mTorr, and etching time of 150 s in order to produce micron structure with tapered etch profile. 15 nm thick Ag film was evaporated on the samples using e-beam evaporator with a deposition rate of 0.05 nm/s. To form Ag nanoparticles (NPs), the samples were thermally treated (thermally dewetted) in a rapid thermal annealing system at $500^{\circ}C$ for 1 min in a nitrogen environment. The Ag thickness and thermal dewetting conditions were carefully chosen to obtain isolated Ag NPs. To fabricate needle-like nanostructures on both the micron structure (i.e., sea urchin-like structures) and flat surface of silicon, MaCE process, which is based on the strong catalytic activity of metal, was performed in a chemical etchant (HNO3: HF: H2O = 4: 1: 20) using Ag NPs at room temperature for 1 min. Finally, the residual Ag NPs were removed by immersion in a HNO3 solution. The fabricated structures after each process steps are shown in figure 1. It is well-known that the hierarchical micro- and nanostructures have efficient light harvesting properties [2-3]. Therefore, this fabrication technique for production of sea urchin-like structures is applicable to improve the performance of light harvesting devices.

• 한국전기전자재료학회논문지
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• 제25권12호
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• pp.943-948
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• 2012

A new water energy harvester module, which is composed of piezoelectric bimorph cantilevers, harvesting circuit and a shaft with 16 impellers at a center axis, was fabricated for energy harvesting application. High energy density $Pb(Zr_{0.54}Ti_{0.46})O_3$ + 0.2 wt% $Cr_2O_3$ + 1.0 wt% $Nb_2O_5$ (PZT-CN) thick film obtained by tape casting method was used for the bimorph cantilever. The PZT-CN bimorph cantilever with a proof mass of 49 g exhibited extremely high output power of 22.5 mW (24 $mW//cm^3$) at resonance frequency of 11 Hz. In addition, the fabricated water energy harvester has a cylindrical structure with 48 bimorph cantilevers clamped at inner surface. A significantly high output power of 433 mW was obtained at a rotation speed of 120 rpm with a resistive load of $500{\Omega}$ for the water energy harvester.

• 한국정보전자통신기술학회논문지
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• 제11권1호
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• pp.89-94
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• 2018

본 논문에서는 IoT (Internet of Things) 서비스 구현을 위한 스마트센서의 설계 방안을 연구하였다. 지속적인 데이터 수집을 위한 센서의 전원 공급부는 에너지 하베스팅 (Energy Harvesting) 기술을 적용하였으며, 주변 환경으로부터 영향을 줄일 수 있는 압전소자 (piezoelectric transducer)를 선택하여 전원 공급부를 설계하였다. 데이터 전송을 위한 무선통신 인터페이스는 BLE (Bluetooth Low Energy) 기술을 적용하여 설계하였다. BLE는 저전력 단거리 무선 통신에 적합하며, 주요 응용분야인 BLE 비콘 (beacon)은 O2O (Online to Offline) 서비스, 실내 측위 기반의 내비게이터, 도난/미아 방지 서비스에서 모바일 게임 등으로 활용 범위가 확대되고 있다. BLE 무선통신의 짧은 전송 거리를 보완하기 위해 무선 커버리지를 확대할 수 있는 방안을 연구하였으며, 네트워크 구축이 용이하고 무선 커버리지 확대할 수 있는 CATV 망을 활용한 BLE 센서 네트워크 구축 방안을 제안하였다.

• 한국도로학회논문집
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• 제13권1호
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• pp.87-96
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• 2011

대량의 화석연료 소비로 인한 지구 생태계의 부작용에 따라 전 세계적으로 저탄소와 지속가능한 신재생에너지의 활용이 요구되고 있다. 본 논문에서는 여름철 아스팔트 포장도로에서 발생하는 열에너지를 열전현상을 이용하여 전기에너지로 변환하여 에너지 위기를 새로운 성장의 기회로 전환하려 하였다. 이를 위해 열발전소자의 전기적 특성실험과 아스팔트 포장도로 시험체에 열발전소자 매입 및 열 회수 파이프 매입 실험을 통해 에너지 하베스팅 전력을 측정하여 가장 효과적인 아스팔트 포장도로의 열에너지 하베스팅을 위한 시스템 구축방안을 검토하였으며, 결국 아스팔트 포장도로에서 발생하는 지속가능한 열 에너지원을 활용함과 동시에 환경보존과 경제성장을 도모할 수 있는 신개념의 녹색도로 사회기반시설을 제안하였다.