Hot forging process design of sprocket wheel and environmental effect analysis

최용진,이상곤,이인규,황선광,윤종천,최창영,이윤선,정명식 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.5

Manufacturing industries have become increasingly conscious of energy wastage and environmental emissions. The energy consumption and environmental effect of each manufacturing process is different. This study aims to compare the environmental effects of the hot forging process and machining process for manufacturing sprocket wheels. It is important to design a preform when forging a sprocket wheel. The sprocket wheel tooth section is the weak point in folding, and an unfilling defect may occur. Therefore, preform and flash stopper shapes are critical design factors in the hot forging process for manufacturing sprocket wheels. Finite element analysis was used to design the preform, and analyze the deformation and effect of flash stopper in the hot forging process. The energy consumption for an actual product and for a product based on the analysis were compared to analyze the environmental effects. The results showed that the material loss and energy consumption were reduced in the developed hot forging process; this process is a green process with comparatively higher energy saving than the machining process.

자외선 유도 그라프트 중합에 의해 재조된 bacterial cellulose-g-acrylic acid의 Pb 흡착거동

최용진,서봉국 한국막학회 2017 한국막학회 총회 및 학술발표회 Vol.2017 No.05

Pb를 흡착처리하기 위해 자외선 유도 그라프트 중합을 사용하여 박테리아 셀룰로스에 아크릴산을 모디피케이션한 흡착제를 제조하였다. 제조된 흡착제는 SEM, FTIRATR등의 기기분석에 의해 평가되었고, 흡착실험 결과를 흡착속도의 거동을 고찰하기 위한 방법으로 pseudo-first-order로 언급되어지는 Benaissa 모델과 pseudo- second-order로 언급되어 지는 Kurniawan 모델에 적용하였다. 제조된 흡착제는 Benaissa 모델에 보다 더 일치함을 보여주었다.

자외선 그라프트 중합법에 의해 제조된 bacterial cellulose-g-acrylic acid의 흡착특성

최용진,이광현 한국막학회 2016 한국막학회 총회 및 학술발표회 Vol.2016 No.11

본 연구에서는 환경 친화적 재료를 제조할 목적으로 자연계에 풍부한 bacteri al cellulose를 지지체로 하여 이온교환 특성이 있는 acrylic acid 단량체를 자외선 그라프트 중합법으로 고정시켰다. 이 중합체를 중금속 흡착제로서 막분리 hy brid시스템에 적용하기 위해 모델 용질로 Pb에 대한 흡착거동을 조사하였고 이에 대한 흡착 등온식 및 Benaissa model과 Kurniawan model 속도식을 적용하여 해석하였다.

미 DMSMS 컨퍼런스 및 국방부 부품단종관리 정책 추진방향 소개

최용진 한국방위산업진흥회 2020 國防과 技術 Vol.- No.499

신·재생에너지 의무할당제에 대한 소고 - 국내 신·재생에너지 보급현황 및 제도개선을 중심으로 -

최용진 아주대학교 법학연구소 2020 중소기업과 법 Vol.12 No.1

왕커핑 목조의 조형적 특성에 관한 연구

최용진 유럽문화예술학회 2015 유럽문화예술학논집 Vol.6 No.1

Wang Keping, a wood carver, was bom at a sma1l town of Hebei Sheng around Beijing with an artistic gift from his parents in 1949. But he had to waste his high school days in a period of Great Cultural Revolution. Then he endeavored to be a writer or film star that he had wanted to be, but he suffered from pang not to select such a job by dint of his rebellious character against Communist system owing to Great Cultural Revolution. As an altemative, he began to paint according to a suggestion by a painter friend, with which he could not be also satisfied, and finally determined to be a sculptor. But whereas painting has a long history in China, sculpture does not. Thus what he sculpts for himself is rather a rational truth more or less. For other sculptors at that time had to trod a road of self-education like him. Theme of his initial sculptures was of rebellion or ridicule against political system without exemption. That is, in the initial sculptures such as Silence, Chain, Idol, Fanatic, etc., he expressed the attack towards Mao Zedong or Chinese people’s appearance suffering from Communist regime metaphorically. By the way, it ostensibly seemed to live the artists freedom of creation since Great Cultural Revolution, but virtually rather strengthened control and surveillance. Artists revoltδd against such an artistic, political establishment of Chinese govemrnent. It was a crisis of Tiananmun. The group that guided them in this protest was very ‘Xing Xing Art Group'. In a demonstration by that group members that compared themselves to an endlessly glittering star, Wang Keping was one of leading persons. They were extremely regulated by the government in the freedom of creation. With three group exhibitions, they not only exploited a road to their own autonomous growth, but guided to a road enough to create and display avant-garde art to young artists. Since then, there was a wave of liberation for a moment, but the government’s suppression was more extreme. As a result, some artists and intellectuals was sent to prison, and he searched for a political asylum with intemational marriage along with other artists. After getting married with a French lady, and defected to France, Wang Keping' s art world reached a tuming point. That is a very transition from the representation of political satire to human body, in particular, to that of pure beauty in female body. And after his defection he concentrated much concem on a medium of tree. In fact, he had showed much concem on tree from the beginning of wood carving in China, it was hard to get timber for carving owing to deforestation since the foundation of China. But the abundant timbers in France served for blooming his artistic inspiration. He began to regard tree as organic body. Thus he did not treat carelessly any of trunk, twig, growth ring, knot, etc. that each tree has. He awakened that they harmonize one another in order to create a tree, and a beaut표버 woman’s body that he wants to represent is formed by their combination. That is, he, 파‘e a Neo-platonist, believed that an idea of a beautiful woman is incamated through a material of tree. It was a reason that he implants woman’s body and tree with life, energy, germination and growth simultaneously. Wang Keping' s philosophy of art started with philanthropy. With an eyewitness that Chinese leaders exerted suppression and surveillance over people in a period of Great Cultural Revolution, his philosophy of philanthropy was germinated. It was a result of far-reaching love towards China. He searched for love towards China from not only such love towards human-being, but 려so that towards tradition of culture and art. But that love was not wide-spread nor comprehensive, rather it was only selected in accordance with his artistic idea. What he preferred to Taoism or Zen Buddhism was not to believe therr~ but to incite only parts harmonized with his own among id않 or spirit contained within them...

전자빔 전조사를 이용한 Polyvinylidene Fluoride 다공막의 친수화 개질

최용진,이성원,서봉국,김민 한국막학회 2011 멤브레인 Vol.21 No.2

본 연구에서는 소수성 표면의 막을 친수화시키는 방법으로 기존의 방법(브렌딩, 화학적처리 및 post-irradiation에 의한 광조사법)의 단점을 극복하기 위해 주고분자에 전자빔을 전조사하는 방법을 제안하였다. 본 연구 제조공정은 4부분으로 구성되며 첫째로 주고분자를 전자빔을 이용하여 수증기 및 공기조건하에서 전조사함으로써 친수기를 도입하는 전구체의 제조공정, 이를 이용하여 도프을 제조하는 도프용액 제조공정, 도프용액을 부직포 위에 캐스팅 하는 캐스팅 공정, 마지막으로 비용매에 침적하여 응고시켜 분리막을 형성시키는 분리막 제조공정으로 이루어진다. 이렇게 제조된 분리막은 기존의 친수화 방법을 통하여 얻어진 다공 분리막에 비하여 보다 균일한 형태의 친수화가 가능하며, 제조공정의 단순화를 꾀할 수 있다는 장점을 가지고 있다. 이를 수행하기 위해 소수성 고분자인 polyvinylidene f1uoride (PVDF)를 75~125 K Gray 범위 선량의 전자빔 (electron beam, EB) 조사하여 전구체를 제조하였다. 제조된 전구체는 FTIR, EDS, DSC 등에 의해 친수기의 도입 및 도입경로를 확인한 결과, 하이드록실기가 친수성기로 도입되었고, 도입경로로는 주쇄의 탈수소화 반응경로에 의해 이루어진 것으로 추론 할 수 있었다. 제조막의 친수화는 접촉각 측정을 통하여 평가하였다.(pristine PVDF로 제조된 막의 접촉각은 약 62℃ 125 K Gray-PVDF로 제조된 막의 접촉각은 13℃). 또한 제조된 PVDF 다공막의 다공성도를 수은압입측정을 통하여 평가하였으며 SEM 이미지를 통하여 몰폴로지 및 표변 공경싸이즈를 관찰하였다. 그들의 결과는 전자빔의 선량이 높게 조사된 PVDF전구체를 사용한 막일수록 공경의 크기 및 다공도(pristine PVDF : 82%, 125 K Gray-PVDF : 63%)가 감소되고 있음을 나타내었다. 순수 투과실험에서도 동일한 경향을 나타내어 pristine PVDF의 경우는 892 LMH, 125 K Gray-PVDF의 경우는 355 LMH의 결과를 얻었다. A method of light pre-irradiation, one of methods modifying hydrophobic surface to hydrophilic surface in a membrane, was proposed to overcome the drawback of previous methods such as blending, chemical treatment and post-irradiation, Process of membrane preparation in the study was comprised of 4 parts as follows: firstly process of precursor preparation to introduce hydrophilic nature under atmosphere and aqueous vapor by irradiating electron beam (EB), secondly process of dope solution preparation to cast on non-woven fabrics, thirdly process of casting to prepare membrane and finally process of coagulation in non-solvent to form porous structure. The merit of this method might show simple process as well as homogenous modification compared to previous methods. To carry it out, precursor was prepared by irradiating EB to powder PVDF at 75~125 K Gray dose. Precursor prepared was analyzed by FTIR, EDS and DSC to confirm the introduction of hydrophilic function and its mechanism. From their results, it was inferred I conformed that hydrophilic function was hydroxy1 and it was introduced by dehydrozenation. Hydrophilicity of membranes prepared was evaluated by contact angle (pristine PVDF : 62℃, 125 K Gray-PVDF13℃). Porosity was evaluated by mercury intrusion method, simultaneously morpholoy and surface pore size were observed by SEM phothographs. The result showed the trend that more dose of EB led to smaller pore size and to lower porosity (pristine PVDF : 82%, 125 K Gray-PVDF : 63%). Trend of water permeability was similar to result above (pristine PVDF : 892 LMH, 125 K Gray-PVDF : 355 LMH).

음원 모델에 기초한 합성음의 피치 조절

최용진,여수진,김진영,성광모 한국음성과학회 1998 음성과학 Vol.3 No.-

Previously developed methods for pitch modification have not been based on the voice source model. Therefore, the synthesized speech often sounds unnatural although it may be highly intelligible. The purpose of this paper is to analyze the alteration of a voice source signal with pitch period and to establish the pitch-modification rule based on the result of this analysis. We examine the alteration of the interval of closing phase, closed phase and open phase using the excitation waveform as the pitch increases. In comparison to the previous methods which performed directly on the speech signal, the pitch modification method based on a voice source model shows high intelligibility and naturalness. This study might benefit the application to the speaker identification and the voice color conversion. Therefore the proposed method will provide high quality synthetic speech. Keywords: pitch modificaion, Laryngograph signal, voice source model

유기폐수로부터 고효율 발효 수소생산을 위한 막농축 반응기의 개발

최용진 한국환경기술학회 2017 한국환경기술학회지 Vol.18 No.6

Separation membrane concentration system was designed to increase the efficiency of hydrogen production from organic wastewater. The permeation characteristics and concentration behavior of the separation membrane were investigated in order to establish the concentration system. The PET support was used as a support and showed excellent interfacial adhesion as compared to PP, and it provided mechanical strength suitable for wastewater in membrane concentration reactor. PVP as a pore-forming agent was more compatible with PVDF than PEG, and it was possible to produce membranes with uniform pore size. Addition of TiO2 could reduce membrane fouling by hydrophilizing hydrophobic PVDF membranes. The permeability of TiO2-dispersed membranes was proportional to the pore size of the membrane whereas the turbidity was independent of the pore size. In the concentration system of the TiO2- dispersed membrane, the cake blocking mechanism was followed for 30 nm pore size, and 100 nm pore size was dominated by cake blocking and internal pore blocking. 유기폐수로부터 수소 생산의 효율성을 높이기 위해 분리막 농축시스템을 설계하였고 이에 대한 농축시스템을 구축하기 위하여 분리막의 제조 및 투과특성 및 농축거동을 조사하였다. 지지체로 PET 지지체를 사용하였고 PP에 비하여 계면접착력이 우수함을 나타내었으며, 하폐수 및 농축시스템에 적합한 기계적 강도를 제공하였다. 기공형성제로서 PVP는 PEG에 비하여 PVDF와 상용성이 높아 균일한 세공경의 막을 제조할 수 있었고, TiO2의 첨가는 소수성의 PVDF막을 친수화 시킴으로써 막오염을 최소화할 수 있었다. TiO2 분산 분리막은 순수투과 특성이 막의 세공경의 크기에 따라 비례하고 있었으나 탁도는 세공경의 크기와는 독립적이었다. TiO2 분산 분리막의 농축시스템에 있어서는 세공경 30 nm의 막의 경우는 cake blocking 메카니즘을 따랐고, 세공경 100 nm막은 cake blocking과 internal pore blocking에 의해 지배되고 있음을 시사하였다.

이온교환막 제조공정의 단순화 연구

최용진,김도형,강문성,서봉국 한국막학회 2016 한국막학회 총회 및 학술발표회 Vol.2016 No.05

상용화되고 있는 이온교환막의 경우 제조공정은 PVC를 분말을 paste로하여 PVC천에 함침시켜 제조하고 있다. 이러한 제조공정은 공정상의 어려움 및 제조 원가의 상승의 요인으로 지적되어 왔고, 이에 최근 PVC 비다공성 필름 지지체 가 특정 모노머에 팽윤하는 성질을 이용하여 함침 시키는 기술이 소개되고 있다. 그러나 이 또한 이온교환기를 도입하기 위해서는 슬폰화반응 및 4급 아민화 반응이 수반되어져야만 한다. 본 연구에서는 이런 이온교환기의 도입공정을 보다 단순화시키기 위한 방안의 제안 및 기초실험과정을 보고하고자 한다.