레일코팅재를 이용한 곡선부 레일마모저감에 관한 실험적 연구

하범용(Beom-Yong Ha),박용걸(Yong-Gul Park),이동욱(Dong-Wook Lee),최정열(Jung-Youl Choi),강윤석(Yun-Suk Kang) 한국철도학회 2011 한국철도학회 학술발표대회논문집 Vol.2011 No.10

The goal of this Paper is to reduce rail's wear in curved track by applying an additional surface layer material(High hardness and High resistance capacity of wear) on the top of the railhead. In order to evaluate appropriation of a coating material experimental tests such as the varieties of fundamental properties tests (hardening wear tensile and bending) and RCF(rolling contact fatigue)test were performed to establish fatigue wear and damage mechanism. As a result wear performance of coating rail is better than heated rail about 6times and normal rail about 8~9times.

서열 자질 및 발현 정보에 기반한 효모의 필수유전자 예측

하범용(Beom Yong Ha),김상수(Sangsoo Kim),황규백(Kyu-Baek Hwang) 한국정보과학회 2009 한국정보과학회 학술발표논문집 Vol.36 No.2A

전기분해에 의해 제조된 NaOCl을 이용한 염색폐수의 처리 특성(II)

윤용수,하범용,Yoon, Yong-Soo,Ha, Beom-Yong 한국섬유공학회 2006 한국섬유공학회지 Vol.43 No.4

This study was performed to determine the feasibility of electrolytically produced NaOCl solution for the treatment of dyeing wastewater discharged from textile industry. Industrial dyeing wastewater was pre-treated by PAC coagulant and the optimal pH and dosage for coagulation were 6.5 and 0.05 v/v%, respectively In this pre-treatment process $COD_{Mn}$, color and suspended solids removal efficiency were 66%, 91% and 85%, respectively. After pre-treatment by coagulation, NaOCl solution made by electrolysis was used for the treatment of industrial wastewater. The optimal mixing ratio with NaOCl solution and dyeing wastewater was determined to be 1:5 at pH 5.0 and in these conditions, color and removal efficiency were 99% and 88%, respectively. From these results, we can expect that NaOCl solution produced by electrolysis with salt of a lower price can be used for the treatment of industrial dyeing wastewater conveniently and effectively, and can overcome disadvantage of a commercial NaOCl solution with a bad storage and delivery properties to decreas oxidation ability.

전기분해에 의해 제조된 NaOCl을 이용한 염색폐수의 처리 특성(I)

윤용수,하범용,노방타잉후이,Yoon, Yong-Soo,Ha, Beom-Yong,Thanh Huy, Ngo Van 한국섬유공학회 2005 한국섬유공학회지 Vol.42 No.5

This study was carried out to investigate the feasibility of using electrolytically generated NaOCl solution for treatment of wastewater containing an acid dye(C.I. Acid Red 114). The NaOCl was produced by the electrolysis of aqueous NaCl solution. In order to asses the treatment characteristics, we evaluated the effect of pH and mixing ratio of the NaOCl solution to colored wastewater on the color and chemical oxygen demand$(COD_{Mn})$ removal. The optimum conditions for the dye and $COD_{Mn}$ removal were determined to be pH 5.0 and mixing ratio of 1 :9, at which more than $88\%$ color and $87\%$ $COD_{Mn}$ were removed within 10 min reaction time. Reaction rate constants for the 300 and 500mg/l of artificially prepared dyeing wastewater were estimated as 0.1764 and $0.1737 min^{-1}$ for color removal and 0.1197 and $0.1436 min^{-1}$ for $COD_{Mn}$ removal, respectively.

순도가 향상된 금속급 실리콘 제조를 위한 산침출 연구

엄명헌(Myeong-Heon Um),하범용(Beom-Yong Ha) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.11

다양한 산업에 사용되고 있는 금속급 실리콘(MG-Si, Metallurgical grade silicon)을 제조하기 위해 실리콘 원료 내 가장 많이 함유하고 있는 불순물인 알루미늄(Al) 및 철(Fe)을 제거하고자 산(Acid) 침출 실험을 수행하였다. 5가지 종류의 산(HCl, HF, H2SO4, HNO3, H3PO4)을 1, 2, 4, 6M로 조제하여 실리콘 원료에 반응시킨 결과, 1M 농도의 HF가 가장 우수한 Al 및 Fe 제거율을 나타내었으며 각각 97.9%와 95.2로 나타났다. 그러나 HF는 실리콘 부식 특성으로 인해 18% 가량의 수율 감소가 발생하였으며 이러한 수율감소를 최소화하기 위해 두 번째로 제거율이 우수하게 나타난 2M HCl과 혼합하여 실리콘 원료에 적용하였다. 혼합용액의 최적조건을 선정하기 위해 실험을 수행하여 80℃, 2시간의 침출 최적조건으로 결정되었으며 이 혼합용액의 적용 결과 Al 및 Fe 잔류농도가 각각 141 ppmw 및 93ppmw로 나타나 3N급의 순도를 갖는 금속급 실리콘을 제조하기에 매우 용이한 것으로 확인되었다. To manufacture MG-Si (Metallurgical grade silicon) for use in various industries, Acid leaching experiments were performed to remove aluminum (Al) and iron (Fe), which are the most common impurities found in the silicon raw material. The silicon raw material was reacted with five types of acids (HCl, HF, H2SO4, HNO3, H3PO4) at 1, 2, 4, and 6M; 1M HF showed the highest Al and Fe removal rates, 97.9% and 95.2%, respectively. HF, however, resulted in an 18% reduced yield due to the silicon corrosion properties. To minimize the yield reduction, 2M HCl, which has a second removal ratio result, was mixed with 1M HF and applied to the silicon raw material. The experiment was conducted to select the optimal conditions for the mixed solution, which were 80℃ and 2hr. Under the optimal conditions, the residual Al and Fe concentrations were 141 ppmw and 93 ppmw, respectively, and it very easy to produce MG-Si with 3N grade purity.

Sol-Gel법을 이용한 γ-Al₂O₃ 합성 시 EAcAc 첨가에 따른 구조적 특성 변화

엄명헌(Myeong-Heon Um),안성윤(Sung-Yun An),하범용(Beom-Yong Ha) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.11

본 연구에서는 다른 종류의 알루미나 필름 제조시 첨가하여 안정적이고 균열형성을 제어할 수 있으며 겔 입자의 밀도를 높여주는 것으로 알려진 EAcAc(Ethyl acetoacetate, CH₃COCH₂COOC₂H5)를 졸-겔법을 이용한 γ-알루미나(γ-Al₂O₃) 제조에 첨가하여 그 구조적 특성변화를 확인하고자 하였다. 이를 위해 졸-겔법에 의해 Aluminum isopropoxide(AIP)을 출발물질로 하여 가수분해로 boehmite 졸을 제조한 후 건조 및 하소시켜 γ-알루미나를 제조하였다. 이러한 제조과정 중, 가수분해 이전에 Ethyl acetoacetate(EAcAc, CH₃COCH₂COOC₂H5)를 첨가하였으며 다양한 EAcAc의 몰비율(1:10, 1:25, 1:60, 1:120), 반응시간(5, 10, 17, 24 시간) 그리고 하소온도(400, 500, 600, 800℃)를 적용시키며 γ-알루미나 파우더를 제조한 결과, 1:25의 EAcAc 몰비율, 24 시간의 반응시간, 그리고 500 ℃의 하소온도에서 가장 높은 순도와 가장 작은 입자크기를 갖는 안정적 γ-알루미나가 생성되었다. 이렇게 최적조건에서 제조된 γ-알루미나에 대해 에너지분산형분광분석법(EDS), X선회절분석(XRD), 고분해능전자주사현미경(FE-SEM), 열중량분석기(TG-DTA) 그리고 푸리에변환적외선분광법(FT-IR) 등의 기기분석을 수행한 결과, 졸-겔법을 이용한 γ-Al₂O₃를 제조과정에서 최적 조건의 EAcAc의 첨가는 안정적인 γ-Al₂O₃ 제조와 더불어 입자크기의 감소, 순도의 향상에 기여하는 것으로 확인되었다. In this study, we confirm the structural properties change due to the addition EAcAc in alumina production using the sol-gel method. EAcAc is known to be stable, controlling the crack formation, and increasing the density of gel particles when added in the manufacture of various alumina films. In this study, a boehmite sol prepared by hydrolysis using aluminum isopropoxide (AIP) was used as a starting material for the sol-gel method. The boehmite preparation was followed by drying and calcining to prepare γ-alumina (γ-Al₂O₃). During this sol-gel process, Ethyl acetoacetate (EAcAc, CH₃COCH₂COOC₂H5) was added before hydrolysis at various EAcAc molar ratios (1:10, 1:25, 1:60, and 1:120), reaction times (5, 10, 17, and 24 hrs), and calcination temperatures (400, 500, 600, and 800 ℃) to prepare γ-alumina powder. The results suggested that under the conditions of EAcAc molar ratio of 1:25, reaction time of 24 hours, and calcination temperature of 500 °C stable γ-alumina with the highest purity and smallest particle size was produced. EDS, XRD, FE-SEM, TG-DTA, and FT-IR analysis were performed on the alumina powder manufactured under the above optimal conditions. It was confirmed from these studies that the addition of EAcAc during the production of γ-Al₂O₃ using the sol-gel method contributes to the stable production of γ-Al₂O₃, reduction of particle size, and improvement of purity.

고밀도 자기기록용 Ba-Ferrite 분말의 자기적 특성에 미치는 첨가제 (Co, Ti, Co-Ti)의 효과

엄명헌(Myeong-Heon Um),연제욱(Je-Uk Yeon),하범용(Beom-Yong Ha) 한국산학기술학회 2022 한국산학기술학회논문지 Vol.23 No.10

본 연구에서는 고밀도 자기기록용 Ba-Ferrite(BaFe12O19) 분말의 자기적 특성에 미치는 첨가제(Co, Ti, Co-Ti)의 효과를 알아보기 위해 Sol-Gel 방법을 이용하여 분말을 합성하였다. 이때 선행연구로부터 얻은 최적의 열처리 온도와 Fe/Ba의 몰 비를 적용하였으며 고밀도 자기기록용 분말에 적합한 Ba-ferrite 미립자를 제조하였다. 형성된 Ba-ferrite 상은 X선회절분석(XRD), 에너지분산형분광분석법(EDS) 측정을 통해 결정구조 및 단일 상의 합성 여부를 확인하였고, 진동시료형자력계(VSM)을 통해 코발트(Co), 티타늄(Ti), 코발트-티타늄(Co-Ti)를 첨가제로 사용한 Ba-ferrite의 보자력과 포화 자화 값을 비교하였다. 결과적으로, Ba에 대한 Fe의 몰 비가 10이고 열처리 온도가 900 ℃의 조건에서 합성된 Barium ferrite는 첨가제를 Co만 사용 시 보자력이 급격히 감소하였고, Ti만 사용 시 보자력이 유지되지만 포화 자화값이 감소하는 문제점이 발생하였다. 이를 보완하기 위해 Co-Ti를 첨가제로 사용한 결과 더 넓은 조성에서 큰 변화없이 포화 자화값이 유지되었고, 고밀도 자기기록매체에 사용할 수 있는 보자력 값인 (2.5 ~ 5.5) kOe를 가지는 Barium ferrite가 합성되었다. This study investigates the effect of additives (Co, Ti, Co-Ti) on the magnetic properties of Ba-ferrite (BaFe<SUB>12</SUB>O<SUB>19</SUB>) powder for high-density magnetic recording. The powder was synthesized using the Sol-gel method. Optimum heat treatment temperature and Fe/Ba molar ratio obtained from previous studies were applied at tins time, and Ba-ferrite particles suitable for high-density magnetic recording powder were prepared. The prepared Ba-ferrite powder was analyzed for crystal structure and single-phase synthesis using an X-ray diffractometer (XRD) and energy dispersive X-ray spectrometer (EDS). The coercive force and saturation magnetization values of Ba-ferrite using cobalt (Co), titanium (Ti), and cobalt-titanium (Co-Ti) as additives were compared through a vibrating sample magnetometer (VSM). Results revealed that the barium ferrite synthesized under the conditions Ba/Fe molar ratio 10 and a heat treatment temperature of 900°C had a sharply decreased coercive force when only Co was used as an additive. However, although the coercive force was maintained when only Ti was the additive, the saturation magnetization value decreased. To compensate for this, Co-Ti was applied as an additive; the saturation magnetization value was maintained without significant change in the broader composition. The resultant barium ferrite synthesized had a coercive force value of (2.5 ~ 5.5) kOe that can be used for high-density magnetic recording media.

나노무기소재 수열합성법에 의한 BaTiO3의 합성 및 응용

엄명헌 ( Eom Myeong Heon ),강학철 ( Kang Hag Cheol ),하범용 ( Ha Beom Yong ) 한국공업화학회 2003 공업화학전망 Vol.6 No.6

졸-겔법을 이용한 γ-Al₂O₃ 합성 시 PVA와 HNO₃ 첨가에 따른 입자크기 제어

엄명헌(Myeong-Heon Um),김나은(Na-Eun Kim),하범용(Beom-Yong Ha) 한국산학기술학회 2019 한국산학기술학회논문지 Vol.20 No.11

세라믹 재료 중 알루미나(Al₂O₃)는 산업에서 널리 사용되는 세라믹 재료로서 최근의 기술발전에 따라 재료 크기가 작아지고 이에 따른 특성이 다양하여 그 중요성이 더해 가고 있다. 본 연구에서는 다양한 알루미늄 알콕사이드 중 Aluminum isopropoxide(AIP)를 출발 원료물질로 하여 졸-겔(Sol-Gel)법에 의해 가수분해 및 해교과정을 거쳐 boehmite 졸을 제조하고 이후 건조 및 하소시켜 γ-Al₂O₃를 제조하였다. 이러한 제조 과정 중 입자의 응집현상을 방지하기 위해 9,000 ~ 10,000, 31,000 ~ 50,000, 89,000 ~ 98,000, 130,000의 분자량을 갖는 4종류의 PVA(Polyvinyl alcohol)를 첨가하고 3종류 질산(0.1, 0.3, 0.5 몰비)을 첨가하여 입자에 미치는 영향을 확인하고자 하였다. 제조된 γ-Al₂O₃는 X선 회절분석기(XRD), X선 형광분석기(XRF), 입도분석기(PSA), 전계방사 주사전자현미경(FE-SEM) 등의 기기분석을 통하여 결정구조 및 조성, 입자크기, 그리고 입자형상을 확인하였다. 그 결과, 약 98.2 %의 순도를 갖는 γ-Al₂O₃가 합성되었으며 첨가되는 질산의 첨가비가 높을수록, 그리고 PVA 분자량이 클수록 입자크기가 감소하고 균일성이 높아지는 것을 확인할 수 있었다. 이러한 결과로부터, PVA와 질산의 첨가비 조절에 따라 γ-Al₂O₃의 제조공정 중 입자크기 제어가 가능할 것으로 사료된다. Alumina(Al₂O₃) is a ceramic material used in industry with a range of particle sizes and characteristics. In this study, a boehmite sol was prepared by a hydrolysis and peptizing process using the Sol-Gel method from aluminum isopropoxide (AIP). γ-Al₂O₃ was prepared by drying and calcining. To prevent particle agglomeration during the manufacturing process, four kinds of polyvinyl alcohol (PVA) with molecular weights of 9,000~10,000, 31,000~50,000, 89,000~98,000, and 130,000 were added and three concentrations of HNO₃ (0.1, 0.3, 0.5 molar ratio) were added to determine their effects on the particles. The crystal structure, composition, particle size and shape of the prepared γ-Al₂O₃ were confirmed through x-ray diffraction (XRD), x-ray fluorescence analyzer (XRF), particle size analyzer (PSA), and field emission scanning electron microscopy (FE-SEM). As a result, γ-Al₂O₃ with a purity of approximately 98.2% was synthesized, and the particle size decreased and the uniformity increased with increasing ratio of HNO₃ addition and PVA molecular weight. From these results, the particle size can be controlled during the manufacturing process of γ-Al₂O₃ by controlling the addition ratio of PVA and HNO₃.

태양광용 웨이퍼 실리콘 폐슬러지로부터 절삭유의 재생

엄명헌(Myeong-Heon Um),이종집(Jong-Jib Lee),하범용(Beom Yong Ha) 한국청정기술학회 2016 청정기술 Vol.22 No.4

본 연구에서는 태양광용 웨이퍼를 제조하는 과정에서 발생하는 실리콘 폐슬러지의 함유물질 중 공정원가의 25% 가량을 차지하고 있는 절삭유를 화학적으로 재생하기 위한 방법을 개발하고자 하였다. 이를 위해 아세톤, HCl, NaOH, KOH, Na2CO3, 불산, 염화메틸렌 등 7종류의 시약이 이용되었으며 다양한 농도로 폐슬러지와 반응을 실시하고 3000 rpm의 속도로 60분간 원심분리를 수행하였다. 그 결과, 실리콘분말 및 금속분말과 같은 고형물과 액상의 절삭유를 분리하기 위한 최적 시약 및 조건이 0.3 N NaOH로 확인되었다. 시판되는 절삭유의 약산성 특성에 맞게 pH 조절이 요구되어 금속분말 제거에 효과적인 0.1 N HCl과 폐슬러지를 먼저 반응시킨 후 0.3 N NaOH로 후처리 한 재생 절삭유의 pH가 6.05로 나타났으며 0.3 N NaOH 단독으로 폐슬러지에 적용하였을 때 보다 우수한 탁도를 나타내었다. 시판용 절삭유와의 특성을 비교하고자 FT-IR 분석을 실시한 결과, 재생유로서의 가능성이 확인되었으며 실험을 통하여 얻어진 절삭유 회수율은 86.9%로 나타났다. In this study, it was to develop a chemical method that can recycle the cutting oil which accounts for about 25% of the cost of the process among containing materials of silicon waste sludge generated in the process for producing a solar cell wafer. The 7 types of reagents have been used, including acetone, HCl, NaOH, KOH, Na₂CO₃, HF, CH₂Cl₂, etc. for this experiment. And It was carried out at a speed of 3000 rpm for 60 minutes centrifugation after performing a reaction with a waste sludge at various concentrations. As a result, the best reagents and conditions for separating the solid such as a silicon powder and a metal powder and liquid cutting oil were identified as 0.3 N NaOH. It is found to be pH 6.05 in a post-processing recycled cutting oil with 0.3 N NaOH after reaction of waste sludge and 0.1 N HCl which is effective to remove metal powder in order to adjust the pH to suit the properties of the weak acid is a commercially available cutting oil and it showed excellent turbidity than when applied to sludge with 0.3 N NaOH alone. The results of FT-IR analysis which can compare the properties of the commercially available cutting oil shows it has a possibility of recycling oil. The cutting oil recovery rate obtained through the experiment was found to be 86.9%.