Enhancement of Coercivity in Sintered Nd-Fe-B Magnets by Grain-Boundary Diffusion of Electrodeposited Cu-Nd Alloys

Sangjun Lee,Jeehye Kwon,Hee-Ryoung Cha,Kyung Min Kim,Hae-Woong Kwon,Junggoo Lee,Dongyun Lee 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.2

We report an enhancement in the coercivity of sintered Dy free Nd-Fe-B magnets from 11.84 to 14.26 kOe by the grain-boundary diffusion of electrochemically deposited Cu-Nd. In the optimized electrochemical deposition and heat treatment conditions, a distinct Nd-rich grain-boundary phase was observed after the diffusion process; distributions of each element was carefully mapped by scanning electron microscopy equipped with backscattered electron detector. X-ray diffraction patterns indicated that Nd2Fe14B was oxidized by the inward diffusion of oxygen, which might be formed during the electrodeposition of Cu-Nd, forming antiferromagnetic Fe2O3 that might degrade the overall coercivity. A mechanism underlying the enhancement of coercivity is basically the same as the well-known proposed mechanism, distribution of a thin Nd-rich phase by grain-boundary diffusion process. In this study, electrochemical deposition process has been extensively investigated, and then the process was demonstrated to be successful and economically useful method to improve coercivity of the magnet.

A Study on the Steering Force Feedback Control of the Steer by Wire System Using HiLS

Sangjun Lee,Yongkwon Lee,Hyunjin Jeong,Minhyuk Lee 한국자동차공학회 2021 한국 자동차공학회논문집 Vol.29 No.1

호흡율 측정기를 이용한 제약폐수의 생물학적 활성 측정

이영락(Lee Youngrak),이기용(Lee Giyong),임지훈(Lim Jihun),이상훈(Lee Sanghun),문흥만(Moon Heungman),심상준(Sim Sangjun),이진원(Lee Jinwon) 한국생물공학회 2001 KSBB Journal Vol.16 No.2

Steer-by-Wire의 조향 반력 제어 유닛 개발에 대한 연구

이상준(Sangjun Lee),이용권(Yongkwon Lee),정현진(Hyunjin Jeong),이민혁(Minhyuk Lee) 한국자동차공학회 2019 한국자동차공학회 학술대회 및 전시회 Vol.2019 No.11

This paper is about Steer-by-Wire of the next generation steering system to be applied to autonomous driving vehicles. This paper covers a study of the Force Feedback Unit in the Steer-by-Wire system that affects the driver’s steering feel. To provide the driver with the same steering feel as the existing Electronic Power Steering system, we selected the target vehicle. And then, we measured and analyzed the results of the Electronic Power Steering system evaluation and applied them to the study before starting the study. To design the Force Feedback Unit, we analyzed the dynamic motion of the vehicle and related parameters and applied them to the vehicle dynamics simulation (dSPACE, ASM). In the Steer-by-Wire system, the column’s Force Feedback Unit control algorithm was model-based designed and the performance was validated at the Hardware in the Loop level.

전기레인지 스위치 오동작에 의한 화재 위험성에 대한 연구

이상준(Lee Sangjun) 한국방재학회 2018 한국방재학회논문집 Vol.18 No.6

As society becomes increasingly modernized and urbanized and as individualism grows stronger, “alone culture” is rapidly increasing and one-person families, or in other words, the culture of people living alone, is strongly establishing itself around us. Almost as a representation of this, products or spaces for those living alone are increasing, and the number of studio apartments offering high efficiency for low prices is increasing geometrically. In accordance with the living environments of those living alone, focus is being placed on simple living spaces that emphasize convenience and contain kitchen appliances that also aim for convenience rather than safety; to suit such living spaces, electric cookers, which can be used more easily than gas stoves, are rapidly becoming popular. Electric cookers, which are becoming popular owing to their high levels of efficiency and environment-friendliness, are manufactured to be flat, compared with gas stoves with their burner pots and trivets that allow objects to be placed on top, providing better space utilization and making them suitable for those living alone. However, such convenience is affecting safety. In particular, products that do not have a switch with a safety device can lead to fires owing to even the smallest of errors that occur in our daily lives, causing significant damage to human life and property. This study aims to discuss the safety of electric cookers with a focus on such cases and to devise measures to minimize such occurrences. 사회가 현대화 도시화되고 개인주의가 발달하면서 나 홀로 문화가 급증하고 1인 가정 즉 혼족 이라는 문화가 우리 주위에 깊게 자리 매김을 하고 있다. 이를 대변하듯 혼족들을 위한 제품이나 공간이 늘고, 낮은 가격으로 고 효율을 노린 원룸이 기하급수적으로 늘고 있는 추세이다. 혼족들의 생활환경에 따라 간단하면서 편의성을 강조한 주거 공간이 맞춰지면서 주방기기 또한 안전 보다는 편의성을 축구하게 되고, 이러한 주거공간에 맞게 가스레인지 보다는 간단하게 사용할 수 있는 전기레인지가 급속하고 보급되고 있다. 고효율과 친환경성을 내세워 보급되고 사용되고 있는 전기레인지는 염공과 삼발이가 장착된 가스레인지에 비해 물건을 올려놓기에도 용의하게 평면으로 설계되어 공간 활용도 또한 혼족에 걸맞은 기기라고 할 수 있다. 그러나 이러한 편의성이 우리의 안전에는 취약하게 작용하고 있다, 특히 안전장치가 없는 스위치의 경우 생활하면서 발생하는 약간의 실수에도 화재로 이어져 인명과 재산의 피해가 막대하게 발생하고 있다. 본 연구에서는 이와 같은 사례를 중심으로 전기레인지의 안전성에 대해 지적을 하고 대책을 강구하고자 한다.

IT학과와 비IT학과 졸업자간의 노동시장성과 비교분석연구

이상돈(Sangdon Lee),이상준(Sangjun Lee),이의규(Eekyu Lee),이중만(Jungmann Lee) 한국콘텐츠학회 2009 한국콘텐츠학회논문지 Vol.9 No.5

본 연구는 IT 졸업자들의 성과를 보기 위하여 IT전공자와 비전공자간의 고용, 임금, 근속기간 등 노동시장의 핵심적인 요인들을 Monte-Carlo와 Calibration 방법인 실증 모형을 통한 추정으로 분석하였다. 연구결과 중 취업에서 실업으로의 이동을 살펴보면, 4년제 IT 전공자는 반복적인 취업에 상관없이 안정적인 근속일수를 보여주고 있으나 비IT학과 전공자의 근속일수는 취업횟수가 반복됨에 따라 줄어들고 있다. IT 관련학과 졸업자들은 여섯 번째 취업까지 비 IT 학과 졸업자에 비해 상대적으로 임금을 더 받는 것을 알 수 있었다. 그리고 임금효과에 대한 실증 분석에서는 대학졸업자의 능력에 대해 통제한 후 대학에서 IT를 전공한 졸업생의 임금은 비 IT 학과 졸업자들에 비해 0.8% 정도의 임금프리미엄이 있었다. 연구의 시사점으로는 첫째 IT 노동시장은 전문대 수준의 기술을 가진 사람보다는 대학 이상의 수준의 인력에 대한 지속적인 수요가 존재하고 있으며 둘째 임금측면에서 볼 때 개인의 능력을 고려할 경우 임금차이는 비록 통계적으로 유의할 지라도 금액상에서 커다란 차이가 없어 IT 전공의 프리미엄은 임금과 같은 근로조건 보다는 취업, 즉 고용의 가능성과 안정성에 있다하겠다. 끝으로 분석을 IT 산업과 다른 산업과 비교하지 못한 점은 연구의 한계로 지적 하고 싶다. This study investigated the labor market outcomes between IT graduates and non-IT graduates in terms of employment, wage, and work period through Monte-Carlo and Calibration method. The empirical result of the movement from work to unemployment implied that IT major graduates have stable work period irrespective of continuous employment, and but the number of work period of non-IT graduates decreases. It also showed that IT related department graduates got relatively paid more than non-IT graduates and IT major graduates was 0.8% higher wage premium than non-IT graduates.

Simple and Versatile Non-Fullerene Acceptor Based on Benzothiadiazole and Rhodanine for Organic Solar Cells

Ahn, Jongho,Oh, Sora,Lee, HyunKyung,Lee, Sangjun,Song, Chang Eun,Lee, Hang Ken,Lee, Sang Kyu,So, Won-Wook,Moon, Sang-Jin,Lim, Eunhee,Shin, Won Suk,Lee, Jong-Cheol American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.33

<P>Most non-fullerene acceptors (NFAs) are designed in a complex planar molecular conformation containing fused aromatic rings in high-efficiency organic solar cells (OSCs). To obtain the final molecules, however, numerous synthetic steps are necessary. In this work, a novel simple-structured NFA containing alkoxy-substituted benzothiadiazole and a rhodanine end group (BTDT2R) is designed and synthesized. We also investigate the photovoltaic properties of BTDT2R-based OSCs employing representative polymer donors (wide band gap and high-crystalline P3HT, medium band gap and semicrystalline PPDT2FBT, and narrow band gap and low-crystalline PTB7-Th) to compare the performance capabilities of fullerene acceptor-based OSCs, which are well matched with various polymer donors. OSCs based on P3HT:BTDT2R, PPDT2FBT:BTDT2R, and PTB7-Th:BTDT2R achieved efficiency as high as 5.09, 6.90, and 8.19%, respectively. Importantly, photoactive films incorporating different forms of optical and molecular ordering characteristics exhibit favorable morphologies by means of solvent vapor annealing. This work suggests that the new n-type organic semiconductor developed here is highly promising as a universal NFA that can be paired with various polymer donors with different optical and crystalline properties.</P> [FIG OMISSION]</BR>

차량 주행성능 분석을 위한 자료 획득 장치 개발에 관한 연구

선우명호(Myoungho Sunwoo),이재인(Jaein Lee),이우택(Wootaik Lee),이상준(Sangjun Lee),주원철(Wonchul Ju),최시홍(Sihong Choi),이상태(Sangtae Lee),이현수(Hyunsoo Lee),이경민(Kyungmin Lee) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.5_1

To evaluate the powertrain performances and driving behavior of a vehicle, it is necessary to survey the driving patterns, which have influences on fuel economy and emissions.<br/> The driving patterns are depended on the driver's habit and the road and traffic conditions. An in-vehicle data acquisition system, which is called Mode Survey System(MOSS), is designed and developed to analyze the driving patterns of the actual driver. Furthermore MOSS would be able to make a common driving mode to be used in emission, fuel efficiency, shift survey, catalyst durability, and other tests using the analyzed driving patterns.<br/> MOSS is a stand-alone system based on the 68HC11 MCU. It mainly consists of an MCU-based Hardware and a PC-based software. MOSS logs various data relating to powertrain and vehicle driving such as vehicle speed, engine RPM, gear position, brake, clutch, fuel consumption, and others. For analysis of the driving data, MOSS software, which is easy to use, can be used to analyze the driving patterns. Both the real-time processing and the post processing function for driving data analysis are available.<br/>

Effect of inhomogeneous broadening on time-resolved photoluminescence in CaAlSiN3:Eu2+.

Lee, Sangjun,Sohn, Kee-Sun Optical Society of America 2010 Optics letters Vol.35 No.7

<P>The decay behavior of CaAlSiN(3):Eu(2+) was monitored as a function of the detection wavelength on the Eu(2+) emission band for various Eu(2+) concentrations from 0.0005 to 0.05. The decay at the higher-energy side was faster and less linear than the lower-energy side decay for all Eu(2+) concentrations. This was due to an inhomogeneous broadening induced by the random distribution of Al and Si ions at a crystallographic site in the CaAlSiN(3) structure and to the successive site-to-site energy transfer. This phenomenon caused a redshift of the Eu(2+) emission band as the Eu(2+) concentration increased.</P>

Design and Implementation of Depth Image Based Real-Time Human Detection

Lee, SangJun,Nguyen, Duc Dung,Jeon, Jae Wook The Institute of Electronics and Information Engin 2014 Journal of semiconductor technology and science Vol.14 No.2

This paper presents the design and implementation of a pipelined architecture and a method for real-time human detection using depth image from a Time-of-Flight (ToF) camera. In the proposed method, we use Euclidean Distance Transform (EDT) in order to extract human body location, and we then use the 1D, 2D scanning window in order to extract human joint location. The EDT-based human extraction method is robust against noise. In addition, the 1D, 2D scanning window helps extracting human joint locations easily from a distance image. The proposed method is designed using Verilog HDL (Hardware Description Language) as the dedicated hardware architecture based on pipeline architecture. We implement the dedicated hardware architecture on a Xilinx Virtex6 LX750 Field Programmable Gate Arrays (FPGA). The FPGA implementation can run 80 MHz of maximum operating frequency and show over 60fps of processing performance in the QVGA ($320{\times}240$) resolution depth image.