이상적 속도 궤적을 이용한 드릴링 공정의 버 최소화에 관한 연구

박민석(Min-Suk Park),전도영(Do-Young Jeon) Korean Society for Precision Engineering 1999 한국정밀공학회지 Vol.16 No.4

티타늄 합금의 평엔드밀 가공 시 공구 방향에 따른 가공성 평가

박민석(Min-Suk Park),이훈희(Hoon-Hee Lee),윤왕호(Wang-Ho Yun),김미루(Mi-Ru Kim) 한국생산제조학회 2023 한국생산제조학회지 Vol.32 No.2

Titanium alloys are classified as difficult-to-cut materials with poor machinability, leading to a continuous demand for the development of machining methods. For machining titanium alloys, various tool orientations can be employed based on the shape of the workpiece, such as the presence of an inclination angle. In this study, machining tests considering tool orientation were performed using a solid carbide end mill tool. The tool orientation was classified into three categories with inclination angles of 90° (Reference), 45° (Upward), and 135° (Downward). The machining tests indicated that the Reference orientation exhibits the longest tool life and best surface roughness. Conversely, the Upward orientation exhibited the shortest tool life, while the Downward orientation exhibited the poorest surface roughness. When considering the Upward and Downward cases, the contact length between the cutting edge and the material becomes longer due to the inclination angle during machining, which in turn affects cutting performance.

고장력 인장봉으로 보강한 RC보의 변형률 예측에 관한 해석적 연구

박민석(Park Min-Suk),신경재(Shin Kyung-Jae) 대한건축학회 2009 大韓建築學會論文集 : 構造系 Vol.25 No.11

There are several methods for strengthened the reinforced concrete beam by using such as a steel plate, carbon fiber plate, tendon and steel bar. An advantage of strengthening by high-strength bars is that the procedure of strengthening construction is simple. The construction for strengthening RC beams with high-strength bars could be done while the building is being used. And the effect of reinforcing is excellent comparing to other strengthening methods. This is an analytical study for strain estimation for strengthened RC beams using high-strength bars. When the strengthened RC beam reaches the yield load globally, rebars embeded in concrete reach the yield strain, but external high-strength bars may not reach the yield strain. In general, the strain value of the externally reinforced bar is less than that of the internally reinforced bar. And the yield strain of high-strength bar is more than that of rebars embeded in concrete. This phenomenon must be considered in the design equation. If the external bar is yielded, the design equation becomes much simpler. If the pre-stress value is high, the external bar could be yielded by adding the stress due to the added load. The purpose of this study is to provide the basic data of the design equation considering the geometry of bars and value of pre-stress.

난삭재 플랜트 부품 가공을 위한 센서 기반 공구상태 모니터링 시스템 개발

박민석(Min Suk Park),김형익(Hyung Ick Kim),이훈희(Hoon Hee Lee),김미루(Mi Ru Kim) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.6

PZT센서를 이용한 철골보 손상계측

서혜원,박민석,이수헌,신경재,Seo, Hye-Won,Park, Min-Suk,Lee, Swoo-Heon,Shin, Kyung-Jae 한국강구조학회 2010 韓國鋼構造學會 論文集 Vol.22 No.5

다양한 모니터링 센서는 구조물의 손상측정과 예측에 많이 사용되고 있다. 광섬유센서, 압전소자(PZT) 센서, MEMS(Micro Electro Mechanical System)센서 등의 스마트 센서는 기존 센서를 대체하여 많은 분야에서 사용되고 있다. 본 논문에서는 PZT센서를 실험체에 부착한 후 충격하중을 가하여 PZT센서의 출력 전압의 특성을 이용하여 실험체의 손상을 예측하고자 하였다. PZT센서를 이용한 보 이음부의 손상실험에서는 $H-400{\times}200{\times}8{\times}13$ 철골을 이용하여 단순보를 제작하고 중앙에 볼트 이음을 하였으며, PZT센서의 민감도 측정을 위해 기존 가속도계의 가속도값과 PZT센서의 전압값의 FFT 결과를 비교하였다. 또한 이음부의 볼트풀림을 이용하여 단순보의 손상을 가정하고 손상계측실험도 병행하였다. 철골 플레이트 보의 손상계측 실험에서는 $PL600{\times}65{\times}5.8$로 단순보 실험체를 제작하여 세 곳에 손상을 주어 충격하중 실험을 하였다. 손상의 정도는 쇠톱을 이용하여 보 단면의 양쪽에 6~42 mm로 절단하였다. FFT를 사용하여 손상의 유무에 따른 고유진동수의 비(${\omega}_c/{\omega}$)를 구하여 손상을 파악하였고 모드에 따른 손상의 위치와 정도를 파악하였다. Various monitoring sensors are used to predict and detect structural damage. Smart sensors, such as glass-fiber sensors, PZT, and MEMS, among others, have replaced traditional sensors. They are now being used in many areas. This study aims to predict the damage by measuring the PZT voltage attached on the specimen by the applied impact load. In the experiment to detect damages in beam connection, simple $H-400{\times}200{\times}8{\times}13$ beams were spliced with bolts. The results of FFT between PZT sensor and accelrometer were compared to measure the sensitivity of the PZT sensor. The damage to the beam was presumed by loosening the bolt, and then the damage measurement was accompanied. Secondly, a steel $PL600{\times}65{\times}5.8$ plate beam was fabricated for the purpose of experimenting on damage measurement. Impact loading test on three different locations was carried out. Damage width varied between 6~42mm on both sides by cutting, using a steel saw. The ratio of frequencies before and after the damage was computed to quantify the damage level by using FFT, and the change in mode pattern with the increased damage was investigated to measure the damage.

한강 상류지역 토양유실에 의한 염류부하지수와 수질의 상관관계

김민희 ( Min Hee Kim ),박민석 ( Min Seok Park ),한준호 ( Jun Ho Han ),정명숙 ( Myeong Suk Jung ),현승훈 ( Seung Hun Hyun ) 한국물환경학회(구 한국수질보전학회) 2011 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2011 No.-

천연 제올라이트와 제올라이트 담체를 이용한 NH₄⁺-N 이온교환 특성 평가

이광현,박민석,주현종,Lee, Kwang Hyun,Park, Min Suk,Joo, Hyun Jong 한국물환경학회 2009 한국물환경학회지 Vol.25 No.5

The ammonium ion exchange characteristics of natural zeolite were investigated to remove ${NH_4}^+-N$. The effect of water temperature, particle size and competitive cation on the exchange capacity was examined. Ammonium ion exchange capacity tended to decrease when the temperature increased from $25^{\circ}C$ to $40^{\circ}C$. Exchange capacity was increased according to the particle size of natural zeolite comes to be small. Batch isotherm experiments were conducted for measuring ammonium ion exchange capacity. The ion exchange capacity was well described either by the Langmuir isotherm model or by the Freundlich isotherm model. The ammonium ion exchange capacity ($q_m$) of zeolite carrier can be calculated $11.744mg-{NH_4}^+/g$-carrier. The ion exchange capacity of manufactured zeolite carrier was showed a similar tendency as ion exchange capacity of powder-sized natural zeolite. Therefore, zeolite carrier can be used for increasing of nitrogen removal efficiency in the wastewater treatment plants.

Ulnar Neuropathy Caused by a Schwannoma in the Guyon’s Cannal

Sang-Min Lee(이상민),Sung-Yong Park(박성용),Min-Suk Park(박민석) 대한정형외과학회 2015 대한정형외과학회지 Vol.50 No.6

척골관 증후군은 수장부 소지구에 있는 척골관에서 척골신경 포착으로 발생하는 압박성 신경병증으로 척골관에서 포착되는 위치에 따라 운동신경증상, 감각신경증상, 또는 운동신경과 감각신경 증상이 함께 나타난다. 손목부위의 결절종이 척골신경을 압박하여 발생하는 것이 가장 흔한 원인이며 다른 원인으로는 척골관을 형성하는 부위의 해부학적 기형, 지방종, 척골동맥의 병변, 유두골의 골절 등이 있다. 신경초종은 수부에서는 드물며 저자들은 척골관에 발생한 신경초종으로 인한 척골 신경병증을 문헌 고찰과 함께 보고한다. Guyon’s canal syndrome is a compression neuropathy of the ulnar nerve entrapment at the wrist. Compression of the ulnar nerve at the wrist by a ganglion, lipomas, diseases of the ulnar artery, fractures of the hamate and trauma is a common etiological factor. We report on a rare case of ulnar neuropathy caused by a schwannoma at the level of Guyon’s canal.

논 토양에서 암모니아 배출 특성 모니터링을 위한 수동식 암모니아 확산형 포집기 이용 사례 연구

김민석,박민석,민현기,채은지,현승훈,김정규,구남인,Kim, Min-Suk,Park, Minseok,Min, Hyun-Gi,Chae, Eunji,Hyun, Seunghun,Kim, Jeong-Gyu,Koo, Namin 한국환경생물학회 2021 환경생물 : 환경생물학회지 Vol.39 No.1

Along with an increase in the frequency of high-concentration fine particulate matter in Korea, interest and research on ammonia (NH₃) are actively increasing. It is obvious that agriculture has contributed significantly to NH₃ emissions. However, studies on the long-term effect of fertilizer use on the ambient NH₃ concentration of agricultural land are insufficient. Therefore, in this study, NH₃ concentration in the atmosphere of agricultural land was monitored for 11 months using a passive sampler. The average ambient NH₃ concentration during the total study period was 2.02 ㎍ m^-3 and it was found that the effect of fertilizer application on the ambient NH₃ concentration was greatest in the month immediately following fertilizer application (highest ambient NH₃ concentration as 11.36㎍ m^-3). After that, it was expected that the NH₃ volatilization was promoted by increases in summer temperature and the concentration in the atmosphere was expected to increase. However, high NH₃ concentrations in the atmosphere were not observed due to strong rainfall that lasted for a long period. After that, the ambient NH₃ concentration gradually decreased through autumn and winter. In summary, when studying the contribution of fertilizer to the rate of domestic NH₃ emissions, it is necessary to look intensively for at least one month immediately after fertilizer application, and weather information such as precipitation and no-rain days should be considered in the field study. 국내 고농도의 초미세먼지 발생 빈도 증가와 함께 그 전구물질인 NH₃와 관련한 연구가 활발히 진행 중이다. NH₃ 배출에 있어 농업의 기여율이 높은 것은 자명한 사실이다. 그러나 비료 사용이 농경지 대기 중 NH₃ 농도에 장기간 미치는 영향에 관련한 연구는 미비한 실정이다. 따라서 본 연구에서는 수동식 NH₃ 확산형 포집기를 활용해 11개월간 농경지 대기 중 NH₃ 농도를 관측하였다. 그 결과 비료 살포 직후 한 달 동안 NH₃ 배출의 영향이 가장 큰 것으로 나타났다. 그 이후 여름철 기온 상승으로 NH₃ 휘발이 촉진되어 대기 중 농도가 증가할 것으로 예상하였으나, 54일간의 지속적인 강우로 인하여 대기 중 높은 암모니아 농도는 관측되지 않았다. 그 후 NH₃ 농도는 가을과 겨울을 거치면서 점차 감소하였다. 비료의 영향력이 감쇠한 시점 이후에는 기온이 감소할수록, 그리고 강수량이 증가할수록 NH₃ 농도는 감소하는 것을 상관분석을 통해 확인할 수 있었다. 종합해 보면, 국내 NH₃ 배출량에서 비료의 기여율을 연구하는 데 있어 비료 살포 직후 최소 한 달 동안은 집중적으로 살펴보아야 할 것이며, 현장 연구 시 강수량과 무강우 일수 등의 기상 정보도 함께 고려해야 할 것이다.

하이브리드 선형이온원에 의한 유압 기어펌프용 Cr-DLC코팅막의 특성과 효율성능

차순용,김왕렬,박민석,권세훈,정원섭,강명창,Cha, Sun-Yong,Kim, Wang-Ryeol,Park, Min-Suk,Kwon, Se-Hun,Chung, Won-Sub,Kang, Myung-Chang 한국분말야금학회 2010 한국분말재료학회지 (KPMI) Vol.17 No.6

This paper describes the results of the application of Cr-Diamond-like carbon (DLC) films for efficiency improvement through surface modification of spur gear parts in the hydraulic gear pump. Cr-DLC films were successfully deposited on SCM 415 substrates by a hybrid coating process using linear ion source (LIS) and magnetron sputtering method. The characteristics of the films were systematically investigated using FE-SEM, nano-indentation, sliding tester and AFM instrument. The microstructure of Cr-DLC films turned into the dense and fine grains with relatively preferred orientation. The thickness formed in our Cr buffer layer and DLC coating layer were obtained the 487 nm and $1.14\;{\mu}m$. The average friction coefficient of Cr-DLC films considerably decreased to 0.15 for 0.50 of uncoated SCM415 material. The hardness and surface roughness of Cr-DLC films were measured 20 GPa and 10.76 nm, respectively. And then, efficiency tests were performed on the hydraulic gear pump to investigate the efficiency performance of the Cr-DLC coated spur gear. The experimental results show that the volumetric and mechanical efficiency of hydraulic gear pump using the Cr-DLC spur gear were improved up to 2~5% and better efficiency improvement could be attributed to its excellent microstructure, higher hardness, and lower friction coefficient. This conclusion proves the feasibility in the efficiency improvement of hydraulic gear pump for industrial applications.