비결정질 실리콘 박막 상에서의 광열 유동을 이용한 액적 조작

이호림(Horim Lee),윤진성(Jin Sung Yoon),김동성(Dong Sung Kim),임근배(Geunbae Lim) Korean Society for Precision Engineering 2014 한국정밀공학회지 Vol.31 No.1

We present a droplet-manipulation method using opto-thermal flows in oils. The flows are originated from Marangoni and buoyancy effects due to temperature gradient, generated by the adsorption of light on an amorphous silicon thin film. Using this method, we can transport, merge and mix droplets in an extremely simple system. Since the temperature rise during the operation is small, this method can be used for biological applications without the damage on cell viability.

아두이노를 활용한 어린이 교통사고 예방 시스템 설계 및 구현에 관한 연구

이호림 ( Horim Lee ),김혜주 ( Hyeju Kim ),이희재 ( Heejae Lee ) 한국정보처리학회 2020 한국정보처리학회 학술대회논문집 Vol.27 No.2

최근 ‘민식이 법’으로 인해 교통사고에 대한 이슈가 대두되고 있다. 어린이는 안전한 횡단을 보장받을 수 있지만, 운전자들이 불편함을 감수해야 하는 단점도 존재한다. 본 논문에서는 어린이도 지금보다 더 안전하게 횡단할 수 있고, 운전자들도 스쿨존에서의 불안감 및 부담을 줄이기 위해 아두이노를 활용한 어린이 교통사고 예방 시스템을 설계하고 구현한다.

유체-구조 연성해석을 이용한 원심압축기 운전익단간극과 성능 예측

이호림(Horim Lee),김창희(Changhee Kim),양장식(Jangsik Yang),손창민(Changmin Son),황윤제(Yoonjei Hwang),정진희(Jinhee Jeong) 대한기계학회 2016 大韓機械學會論文集B Vol.40 No.6

본 연구에서는 날개 두께 분포가 다른 두 임펠러를 이용하여 유체-구조 연성해석을 통해 운전익 단간극을 예측하고 임펠러의 변형이 성능에 미치는 영향에 대해 연구하였다. 임펠러는 작동조건에서 작용하는 원심력, 압력, 열 하중의 영향으로 변형이 발생하게 된다. 이로 인해 초기 설계된 익단간극이 비균일하게 변화하는 것을 확인하였다. 특히 임펠러 날개의 선단과 후단에서 가장 큰 익단간극 감소가 발생하였으며, 이로인해 간극누설유동이 19.4% 감소하였다. 또한 운전조건에서 익단간극 감소로 간극누설 유량이 감소하면서 효율은 0.72% 증가하는 것을 확인하였다. 원심압축기 작동조건에서의 정확한 운전익단간극의 예측과 익단간극의 변화가 성능에 미치는 영향에 대해서 확인하였다. In this study, we perform a series of aero-thermo-mechanical analyses to predict the running-tip clearance and the effects of impeller deformation on the performance using a centrifugal compressor. During operation, the impeller deformation due to a combination of the centrifugal force, aerodynamic pressure and the thermal load results in a non-uniform tip clearance profile. For the prediction, we employ the one-way fluid-structure interaction (FSI) method using CFX 14.5 and ANSYS. The predicted running tip clearance shows a non-uniform profile over the entire flow passage. In particular, a significant reduction of the tip clearance height occurred at the leading and trailing edges of the impeller. Because of the reduction of the tip clearance, the tip leakage flow decreased by 19.4%. In addition, the polytrophic efficiency under operating conditions increased by 0.72%. These findings confirm that the prediction of the running tip clearance and its impact on compressor performance is an important area that requires further investigation.

전기 영동에서의 입자간의 전기력에 의한 상호 작용

이호림(Horim Lee),강관형(Kwan Hyoung Kang) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-

When two particles close to each other are in electrophoretic motion, each particle is under the influence of the non-uniform electric field generated by the other particle. Two particles may attract or repel each other due to the dielectric force depending on their positions in the non-uniform electric field. It is shown analytically that two adjusting rigid particles can form an aggregate due to the dielectric interaction. To verify the validity of the theoretical prediction, an experiment is carried out by using a microchannel. In the experiment, AC electric field is used to eliminate cumbersome electroosmotic flow. The experimental result shows that the particles form a chain-like structure, which is typically observed in electro-rheological fluid, due to the dielectric interaction.

AC 전기습윤 중 전기수력학 유동의 메카니즘

이호림(Horim Lee),고성희(Sung Hee Ko),윤성찬(SungchanYun),강관형(Kwan Hyoung Kang) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11

In AC electrowetting, it has been reported that there is a flow inside droplets. The flow characteristics such as flow rate, direction and the pattern of streamline are altered according to the frequency range of applied voltage. However, the mechanism of the flow has not been explained yet. This work is concentrated on investigation of the flow mechanism when high-frequency voltage is applied to droplets. We propose that this phenomenon arises from the electro-thermal flow. A numerical analysis is performed for the needle-electrodeplane geometry in which the Coulombic force term is included in the Navier-Stokes equation. According to our analysis, electrical charge is generated due to conductivity gradient which is originated from the nonuniform Joule heating of fluid medium. The result of the analysis is compared with experimental result.

전기영동에서 입자 응집체 형성의 특성

이호림(Horim Lee),강관형(Kwan Hyoung Kang) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

In the capillary electrophoresis of micro particles, an aggregate of particles was often observed. Such a phenomenon occurs for various particles such as the sperm cells, chromosomes, and DNAs. It is still unclear how the aggregation is produced. We carried out an experimental investigation to show the dielectric interaction plays a key role in the formation of aggregates. A low frequency(~1㎑) AC field was applied to polystyrene microspheres for elimination of the electroosmotic flow and other side effects, such as the hydrodynamic interaction. Immediately after applying AC field, randomly distributed particles begin to interact with nearest ones and form chain-like aggregates. The particle chains are aligned parallel to the direction of applied electric field. The motion of interacting particles is compared with the previous analytical prediction. We will show characteristics of particle aggregation in various conditions of field strength, frequency, particle size.

AC 전기삼투 유동에 관한 전기이중층 모형들의 타당성 검토

이호림(Horim Lee),강관형(Kwan Hyoung Kang) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10

In AC elctroosmotic flow (ACEOF), the Helmholtz and Smoluchowski’s slip condition has been used as a boundary condition which should have been more carefully considered. In this work, we explain why the condition should be corrected and propose a newly corrected slip condition.

롤투롤 제조 공정을 이용한 전자피부용 신축성 촉각센서 제작 및 절연층 두께 최적화

이호림(Horim Lee),신재학(Jaehak Shin),진신양(Chenyang Qin),이동진(Dongjin Lee) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.6

한국 트랜스젠더 의료접근성에 대한 시론

이호림 ( Yi Horim ),이혜민 ( Lee Hyemin ),윤정원 ( Yoon Jung Won ),박주영 ( Park Jooyoung ),김승섭 ( Kim Seung-sup ) 한국보건사회연구원 2015 保健社會硏究 Vol.35 No.4

한국에서 트랜스젠더의 의료접근성에 대한 논의는 전무하다. 본 연구는 한국 트랜스젠더의 의료접근성을 제도적 측면과 의료공급자 측면으로 나누어 살펴보고, 이와 관련한 외국의 현황과 그동안 진행된 논의를 소개하고자 한다. 트랜스젠더는 성별위화감 진단, 호르몬요법, 성전환수술 등의 성별 트랜지션(gender transition) 관련 의료적 조치와 더불어 성별정체성을 고려한 생애주기별 일반 건강관리 등과 같은 고유한 의료적 필요를 가지고 있다. 그러나 현재 한국에서는 트랜지션과 관련하여 의료적 조치에 대한 의료보장의 부재와 트랜스젠더에 대한 의료진의 편견 및 숙련된 의료진의 부족으로 인해 트랜스젠더의 의료접근성은 심각하게 제한되고 있다. 외국 연구들은 트랜지션 관련 의료보장의 부재는 호르몬 자가처방이나 자가거세 등을 증가시켜 건강을 해치며, 삶의 만족도를 떨어트린다는 점을 보여주고 있다. 이러한 결과에 기반하여 전 세계 118개국중 43개국에서는 호르몬요법 또는 성전환수술을 의료보장에 포함하고 있으며 트랜스젠더 친화적인 숙련된 의료진을 양성하기 위해 의학교육과 의료진 수련 과정에서 다양한 시도가 모색되고 있다. 트랜스젠더에게 의료접근성은 신체적·정신적 질병을 치료하거나 예방하기 위해 필요한 것 이상의 의미를 지니는 중요한 삶의 조건이다. 한국 트랜스 젠더의 의료접근성을 높이기 위한 적극적인 논의와 정책 수립이 필요한 시점이다. This research examined current barriers that prevent transgender people from accessing health care in Korea and reviewed what has been discussed and what efforts have been made in some other countries to improve health care access of transgender people. Transgender-specific medical necessities include not only medical transition but also general health care throughout life course. However, Korean transgender people`s access to health care is significantly limited due to the absence of health care coverage on medical transition, cultural prejudice and discrimination of medical personnels, and shortage of well-trained surgeons. Previous literatures reported that lack of health care coverage on medical transition may increase self-prescribed hormone use and self-castration, which can severly damage their health. Currently, 43 out of 118 nations cover transition-related care in national health insurance or public health system. Studies also address that transgender-specific cultural competency educations and training programs are necessary for medical personnels. Future research is required to find effective strategies to improve transgender people`s access to health care in Korea.

하소온도가 M형 페라이트 복합재의 전자파 흡수 특성에 미치는 영향

천성준,최재령,이상복,이제인,이호림,Seong Jun Cheon,Jae Ryung Choi,Sang Bok Lee,Je In Lee,Horim Lee 한국복합재료학회 2023 Composites research Vol.36 No.5

In this study, we investigated the electromagnetic properties and microwave absorption characteristics of M-type hexagonal ferrites, which are known as millimeter-wave absorbing materials, according to their calcination temperature. The M-type ferrites synthesized using a molten salt-based sol-gel method exhibited a single-phase M-type crystal structure at calcination temperatures above 850℃. The synthesized particle size increased as well with the calcination temperature. Saturation magnetization increased gradually with increasing calcination temperature, but coercivity reached a maximum at 1050℃ and then rapidly decreased. After preparing a thermoplastic polyurethane (TPU) composite containing 70 wt% of M-type ferrites, we measured the complex permittivity and permeability in the Q-band (33-50 GHz) and V-band (50-75 GHz) frequency ranges, where ferromagnetic resonance occurred. Strong magnetic loss from ferromagnetic resonance occurred in the 50 GHz band for all composite samples. Based on the measured results, we calculated the reflection loss of the TPU/M-type ferrite composite. By calculating the reflection loss of the M-type ferrite composite, the M-type ferrite calcined at 1250℃ showed excellent electromagnetic wave absorption performance of more than -20 dB at 52 GHz with a thickness of about 0.5 mm.