CO₂ 무 배출 침탄 열처리된 SCM415H 소재의 기계적 성질

변재혁,노승훈,이종형,이창헌,양성현,Byun, Jae-Hyuk,Ro, Seung-Hoon,Lee, Jong-Hyung,Lee, Chang-Hun,Yang, Seong-Hyeon 대한기계학회 2012 大韓機械學會論文集A Vol.36 No.9

Vacuum carburizing is supposed to be the superior process to the gas carburizing. However, the vacuum carburizing has the stage in which hydrocarbon gas is supplied into the furnace to be pyrolysis, and consequently the stable heat treatment is hard to achieve due to the soot from the hydrocarbon pyrolysis. Recently, many studies have been made which utilize acetylene gas to overcome this defects. In this paper, the carburizing and the diffusion periods have been selected based on the Harris experimental formula, and the mechanical properties of the vacuum carburized specimen have been compared with those of the gas carburized SCM415H specimen to identify the feasibility of the $CO_2$ free vacuum carburizing process. The result showed that the vacuum carburized materials used have no oxidization of the grain boundaries, and show the 29.8% higher effective hardness depth and the acceptable tensile strength. 진공침탄법은 이산화탄소의 발생이 없는 친환경적인 열처리 방식으로 알려져 있다. 그러나 진공침탄법은 탄화수소 가스(메탄, 프로판)를 노내에 직접 공급하여 열분해하는 과정을 거침으로써 노내에 그을음이 발생하여 안정적인 조업이 불가능한 단점이 있다. 최근에는 이러한 단점을 극복하기위한 불포화 탄화수소인 아세틸렌가스를 이용한 진공침탄법이 활발히 연구되고 있다. 본 논문에서는 아세틸렌가스를 이용한 진공침탄방식의 침탄 및 확산 시간을 변수로 하여 여러 가지 조건에서 열처리를 진행한 후 가스침탄 열처리된 소재와 기계적 성질을 비교 분석하여 이산화탄소 무 배출 진공침탄 열처리 방법의 활용가능성을 확인하였다. 연구결과 본 연구에서 시도된 진공침탄법은 가스침탄에서 나타나는 입계산화층이 발생하지 않았으며 경도 값은 진공침탄 시험편의 유효경화 깊이가 29.8% 크게 나타났으며 인장강도는 가스침탄보다 10%낮게 나왔으나 허용치를 충분히 만족하는 수준이었다.

CO₂ 무 배출 침탄 열처리된 SCM415H 소재의 기계적 성질

변재혁(Jae Hyuk Byun),노승훈(Seung Hoon Ro),이종형(Jong Hyung Lee),이창헌(Chang Hun Lee),양성현(Seong Hyeon Yang) 대한기계학회 2012 大韓機械學會論文集A Vol.36 No.9

진공침탄법은 이산화탄소의 발생이 없는 친환경적인 열처리 방식으로 알려져 있다. 그러나 진공침탄법은 탄화수소 가스(메탄, 프로판)를 노내에 직접 공급하여 열분해하는 과정을 거침으로써 노내에 그을음이 발생하여 안정적인 조업이 불가능한 단점이 있다. 최근에는 이러한 단점을 극복하기위한 불포화 탄화수소인 아세틸렌가스를 이용한 진공침탄법이 활발히 연구되고 있다. 본 논문에서는 아세틸렌가스를 이용한 진공침탄방식의 침탄 및 확산 시간을 변수로 하여 여러 가지 조건에서 열처리를 진행한 후 가스침탄 열처리된 소재와 기계적 성질을 비교 분석하여 이산화탄소 무 배출 진공침탄 열처리 방법의 활용가능성을 확인하였다. 연구결과 본 연구에서 시도된 진공침탄법은 가스침탄에서 나타나는 입계산화층이 발생하지 않았으며 경도 값은 진공침탄 시험편의 유효경화 깊이가 29.8% 크게 나타났으며 인장강도는 가스침탄보다 10%낮게 나왔으나 허용치를 충분히 만족하는 수준이었다. Vacuum carburizing is supposed to be the superior process to the gas carburizing. However, the vacuum carburizing has the stage in which hydrocarbon gas is supplied into the furnace to be pyrolysis, and consequently the stable heat treatment is hard to achieve due to the soot from the hydrocarbon pyrolysis. Recently, many studies have been made which utilize acetylene gas to overcome this defects. In this paper, the carburizing and the diffusion periods have been selected based on the Harris experimental formula, and the mechanical properties of the vacuum carburized specimen have been compared with those of the gas carburized SCM415H specimen to identify the feasibility of the CO₂ free vacuum carburizing process. The result showed that the vacuum carburized materials used have no oxidization of the grain boundaries, and show the 29.8% higher effective hardness depth and the acceptable tensile strength.

고령쥐를 이용한 비수리 추출물의 남성갱년기 증상 개선 및 테스토스테론 대사에 미치는 영향

변재혁(Jae-Hyuk Byun),정세영(Se-Young Choung) 대한약학회 2019 약학회지 Vol.63 No.6

This study focused on the effects of Lespedeza cuneata extract (LCE) to andropause symptoms in aged male Sprague-Dawley (SD) rats. SD rats were randomly divided into control or LCE treatment groups (125 or 250 mg/kg/day) and LCE was orally administered for 4 weeks. The body fat weight was decreased, and muscle weight was increased by LCE treatment. Also, the amount of semen and the number of sperm were increased. Serum levels of lipids (TG and TC) were decreased and total and free testosterone levels were increased. On the contrary, sex-hormone-binding-goblin (SHBG) and prostate specific antigen (PSA) levels were significantly decreased by LCE treatment. We examined the gene expressions involved in the synthesis or degradation of testosterone. The gene expression levels of CYP11A1, 17, 20- desmolase, 3β-HSD2 and 17β-HSD3 which are involved in testosterone synthesis were increased by LCE treatment. Furthermore, aromatase and 5α-reductase which are involved in testosterone degradation were decreased by LCE treatment. In conclusion, LCE suppressed andropause symptoms in aged SD rats via improving testosterone metabolic pathway.

SMEDDS를 이용한 naproxen의 용출률 개선 및 in vivo 효능 평가

변재혁(Jae-Hyuk Byun),조성완(Seong-Wan Cho) 한국산업기술융합학회(구. 산업기술교육훈련학회) 2024 산업기술연구논문지 (JITR) Vol.29 No.1

Naproxen은 비스테로이드성 진통소염제로, 통증, 염증, 해열제로서 사용되고 있다. 반감기가 길어서 효능이 오래 지속되어 환자들의 만족도가 높지만 용해도가 매우 낮다(in water 15.9mg/L). 용해도와 용출률을 높이기 위해 self-microemulsifying delivery system (SMEDDS)을 이용하여 가용화 시켰다. 주로 사용된 oil은 Labrasol ® 이고, 계면활성제로는 Labrafil ® M1944, Cremophor ® RH-40을 사용하였다. 선택한 oil과 계면활성제의 비율을 상평형도로 용해도가 좋은 영역을 도출하였다. 그 다음 적용 가능한 범위 내에서 효능을 확인하였다. 본 실험에서 만든 SMEDDS 로 naproxen을 가용화한 제제는, naproxen에 염을 붙인 정제 제품보다 용출률이 높았고, naproxen emulsion이 봉입된 연질캅셀 제품보다 위염 동물모델에서 위염 개선 능력 또한 뛰어난 것을 확인하였다. 본 연구 에서 naproxen의 SMEDDS의 적절한 oil과 비율을 제시하고, 효능, 용출률 및 안정성을 확인함으로써, 앞으로 naproxen 연구 및 제조의 방향성에 도움을 줄 것이다. Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) administered to reduce pain, inflammation, and fever. The extended half-life of naproxen enables prolonged efficacy, leading to symptom relief and high patient satisfaction. However, naproxen has notably low solubility in water (15.9 mg/L). The present study aimed to enhance the solubility and dissolution rate of naproxen by using a self-microemulsifying delivery system (SMEDDS). Labrasol® was used as the primary oil and Labrafil® M1944 and Cremophor® RH-40 as the surfactants in the SMEDDS. The ratio of the selected oil to the surfactant was determined to identify the equilibrium range with good solubility. Subsequently, the efficacy was confirmed to be within the applicable range. The results indicated that the SMEDDS formulation showed higher dissolution rates than the salt-formulated purified naproxen product. Furthermore, the efficacy was compared with that of commercially available naproxen emulsion-filled soft gel capsules in an animal model of gastric ulcers, showing the excellent gastro-protective abilities of the naproxen SMEDDS. This study provides an appropriate oil and ratio for a naproxen SMEDDS, confirming it sefficacy, dissolution rate, and stability. These results will guide future directions in naproxen research and manufacturing.

FPCB 열압착 프레스 개발에 관한 연구

안재우(Jae-Woo An),이창헌(Chang-Heon Lee),변재혁(Jae-Hyuk Byun),이종형(Jong-Hyung Lee) 한국산업융합학회 2008 한국산업융합학회 논문집 Vol.11 No.4

The bigger size of the wafer to the meet the need of higher productivity and the smaller digital products for convene are examples of the main trends of the market among others. The higher integrity of chips is also an important task in semiconductor industry. In this thesis the COF(chop on film) technology has reviewed to investigate the best combinations of required functions and to develop a new system to save the installation area and to adapt to the variation of layout with flexibility. The new system shows the better and provides the improved safety with smaller size.

정류자를 이용한 절삭기계 개발에 관한 연구

최재혁(Jae-Hyok Choi),이종형(Jong-Hyung Lee),이창헌(Chang-Heon Lee),변재혁(Jae-Hyuk Byun),이재열(Jae-Yul Lee),노승훈(Seung-Hoon Ro) 한국산업융합학회 2008 한국산업융합학회 논문집 Vol.11 No.3

Commutator which plays the major role in switching electric currents from AC to DC is composed of copper and molding compound. The longevity of the DC motors are mostly hampered by the improper machining of the parts. Smooth surface will be mandatory to create the proper air gap of the commutator. In this thesis the selection of the proper materials and tools, the design and analysis of machine structure and the final test procedures have been investigated to achieve the smooth cut surface of the commutators. The performance and the product of the newly manufactured machine has been compared with those of the existing one. And the test result shows the new sawing machine has better overall efficiency and durability.

클러치 마스터 실린더의 성능최적화에 관한 연구

이춘곤(Chun-Kon Lee),이창헌(Chang-Heon Lee),변재혁(Jae-Hyuk Byun),이재열(Jae-Yul Lee),노승훈(Seung-Hoon Ro),이종형(Jong-Hyung Lee) 한국산업융합학회 2008 한국산업융합학회 논문집 Vol.11 No.4

The demand for the lighter parts compels new composite materials composed of nylon66 and glass fiber to be used for the clutch control hydraulic system to achieve the low cost, light weight and the simple production process. In this paper the feasibility of using those composite materials for the clutch system has been investigated. And the efforts have been concentrated to enhance the durability and the credibility of the system. The procedure has been developed to design the clutch system to satisfy the categories mentioned above and to analyze the durability of the system and to setup a simulation program for the realistic driving situations.

복합소재를 이용한 자동차 클러치 커넥터 안정성에 관한 연구

이창헌(Chang-Heon Yi),이종형(Jong-Hyung Lee),변재혁(Jae-Hyuk Byun) 한국기계가공학회 2013 한국기계가공학회지 Vol.12 No.3

Recently, energy-saving technology is rapidly becoming a crucial issue for mankind due to the depletion of natural resources. From this perspective, every automobile manufactures are trying to develop light materials and to validate safety with environmental consideration. In this study, we developed clutch connector tube which is the parts of power transferring clutch with light materials to substitude for existing general steel materials. We also verified that the general steel materials can be replaced with nylon, fiberglass, stainless and plastic materials or not. As a result, we verified that the mixture of glass and nylon composite material can substitude the general steel.