중온 침출수 재순환 혐기성 소화 시스템을 이용한 음식물류 폐기물 처리

조찬휘ㆍ이병희ㆍ이용운(Chan Hui ChoㆍByong hi LeeㆍYong Woon Lee) 유기성자원학회 2016 유기물자원화 Vol.24 No.1

본 연구에서는 침출수 재순환 시스템을 적용한 중온 혐기성소화를 이용하여 음식물류 폐기물을 분해하여 메탄가스를 생산하였다. 실험은 36℃로 유지되는 항온수조 내에 생물반응조와 침출수 저장조로 구성된 2개의 동일한 시스템(System A, System B)을 사용하였고, 생물반응조 하단 30 mm위에는 스크린이 있어 고액분리를 하여 침출수 저장조로 침출수를 이송하였다. 침출수 재순환은 매일 수행하였으며, 침출수 재순환 시에는 생물반응조 하단에서 침출수 저장조로 2.5 L를 30분간 이송한 뒤 다시 침출수 저장조에서 생물반응조 상부로 2.5 L를 30분간 주입하였다. 주입된 음식물류 폐기물은 수집되기 전 한 번 세척하였으며 반응조에 주입되기 전에 36℃로 온도를 올렸다. System A에 49.1 g VS, System B에 54.0 g VS을 2주 간격으로 투입하였다. 저해인자로 측정된 항목은 NH₄⁺-N과 염도였으며, 두 가지 항목의 농도 모두 시스템에 끼친 영향은 없는 것으로 나타났다. System A는 112일간, System B는 140일 동안 운전하였는데, 각 시스템에서 인발된 슬러지는 없었다. 음식물류 폐기물의 혐기성 소화를 통한 평균 메탄 발생량은 System A의 경우 0.439 L CH4/g VS, System B의 경우 0.368 L CH4/g VS로 나타났다. In this study, mesophilic anaerobic digestion of source separated food waste was carried out by leachate recirculation system and methane gas was produced. Two systems - system A and B were fabricated and placed within water bath to maintain 36℃. Each system was comprised of an anaerobic bioreactor and a leachate tank. Leachate in bioreactor was separated through the screen located at 30 mm above the bottom and a pump was installed to transfer collected leachate to the leachate tank. Everyday, 2.5 L of the leachate was pumped from the bioreactor to the leachate tank for 30 min and transferred leachate was pumped back to the top of the bioreactor for 30min, sequentially. Source separated food waste used for this experiment was washed by water before transferring to the laboratory. Transferred food waste was warmed to 36℃ before being fed to bioreactors. System A was fed to 49.1 g VS (Volatile Solids) and System B was fed to 54.0 g VS at every two weeks, respectively. NH₄⁺-N and salinity were monitored to see the inhibition toward anaerobic bioreaction and it was found that concentrations of these materials were not high enough to affect the bioreaction. Although the food waste was fed biweekly for 112 days and 140 days at system A and B, respectively, there was no sludge withdrawal from each system. Average methane productions rates were 0.439 L CH4/g VS and 0.368 L CH4/g VS for system A and B, respectively.

Reference Map of Soluble Protenis from Salmonella enterica Serovar Enteritidis by Two-Dimensional Electrophoresis

김곤섭,Eung-goo Lee,Yong-hwan Kim,정태성,Yong-seung Shin,Gee-wook Shin,Hui-guen Cha,Mi-rim Park 대한수의학회 2003 Journal of Veterinary Science Vol.4 No.2

Map of Soluble Proteins from Salmonella enterica Serovar Enteritidis byTwo-Dimensional ElectrophoresisMi-rim Park, Eung-goo Lee, Yong-hwan Kim, Tae-sung Jung, Yong-seung Shin, Gee-wook Shin, Hui-guen Cha and Gon-sup Kim*Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, KoreaReceived May 17, 2003 / Accepted July 23, 2003J. Vet. Sci. (2003), 4(2), 143-149JOURNAL OFVeterinaryScience*Corresponding author: Gon-sup Kim Laboratory of Veterinary Biochemistry, Collage of Veterinary Medicine, Gyeongsang National University, 900 Gazwa, Jinju 660-701 Korea Tel: +82-55-751-5823, Fax: +82-55-751-5803 E-mail: gonskim@nongae.gsnu.ac.kr

실리콘 카바이드 쇼트키 다이오드에서 역방향 항복전압의 개선을 위한 구조 설계

이용재,정희종 동의대학교 산업기술개발연구소 2006 産業技術硏究誌 Vol.20 No.-

초고내압의 소자제작을 위해서 기존의 실리콘 재질 대신에 물질은 탄화규소(4H-SiC)이며, 기판은 에피층의 두께 12㎛, 농도 5×10^(15)cm^(-3)의 드리프트 층의 웨이퍼이다. 탄화규소( 4H-SiC) 기판에 접합 장벽 쇼트키 다이오드를 설계 제작하였다. 역방향 항복전압 특성을 개선시키기 위해서, 구조적으로 쇼트키 활성영역 내에 보호테의 폭 3㎛를 갖는 P^(+)형 영역을 설계하였으며, 공정은 이온주입 공정을 통해 알루미늄을 확산 형성하였다. 설계 및 제작한 소자의 온-상태 전압이 1.26V, 온-상태 저항은 45㏁/㎠이며, 개선된 역방향 항복전압은 1,260V의 최대값이며, 이 항복 전압의 역방향 누설전류 밀도는 2.26×10^(-5)A/㎠으로 비교적 낮은값으로 항복전압과 누설전류 밀도의 개선이 이루어졌다.

정전분무를 이용한 MOCVD에 의해 증착된 TiO_2 박막의 특성 연구

이영섭,박용균,이성재,조동율,천희곤 울산대학교 2002 공학연구논문집 Vol.33 No.1

정전분무(electrostatic spray)를 이용한 MOCVD방법은 원료를 함유하는 용액을 이용함으로써 이송관의 가열이 필요 없이 장치를 간단하게 할 수 있고, 용액의 유량과 전기장의 세기에 따라 초미세 입자제어도 가능하며, 출발 용액으로부터 박막의 조성을 조절할 수 있는 등의 여러 가지 특징을 가지고 있다. 온도가 증가함에 따라 입자성장과 반응가스에 의한 표면의 밀도가 감소하여 표면조도가 증가하였다. 증착 시간이 증가함에 따라 막의 두께는 증가하지만, 증착시간이 지날수록 +전하를 띤 액적들은 이미 생성된 막의 영향으로 -가 인가된 기판으로의 전하이동을 방해받으므로 island성장과 모세관현상의 표면형상은 거칠고, porous해졌다. 인가전압이 증가할수록 분무시 액적의 사이즈가 작아지므로 막의 표면은 치밀해졌으며, 표면에는 완전분무하지 못한 모액적에 의해 생긴 입자의 수도 적은 경향을 보였다. 산소 분말이 증가할수록 Ti와 O의 세기는 증가하나, C의 세기는 감소하는 경향을 보였다. The electrostatic spray assisted MOCVD has the advantages of simple apparatus without the gas lines, easy control of nano-sized droplets by applied voltage and solution rates and easy control of compositions of thin films by controlling the composition of starting solution. At lower deposition temperatures the morphology of the layers are less porous and rough. With increasing deposition time and thus increasing layer thickness the morphologies of the layers are shift to porous top layer with dense bottom layer and then porous top layer with big sized grain of bottom layer as the result of low growth rates. XPS can be seen that Ti and O intensity increases but C intensity decreses with increasing O_2 flow rates.

비선형시스템 제어를 위한 새로운 신경회로망 제어방식

이용구,김희곤,엄기환 동국대학교 산업기술환경대학원 1996 산업기술논총 Vol.3 No.-

In this paper, we designed a nonlinear controller using a new identification method of neural network. The method proposed in this paper performs, for a nonlinear plant with unknown parameters, identification with using a neural network, and then a stable nonlinear controller is designed with those identified informations. The advantage of the proposed control method is simple to design a controller because, for unknown nonlinear systems, we used the identified informations and design parameters are positioned within a negative real part of s-plane. In order to verify excellent control performances of the proposed method, we compared with a conventional neural network control method through a lot of simulations with one link manipulator.

우리나라 청정지역에서 측정한 PM_(2.5) 입자의 특성

이종훈,김용표,문길주,김희강,정용승,이종범 江原大學校 附設 環境硏究所 1998 環境硏究 Vol.15 No.-

Atmospheric fine particles (PM_(2.5)) were collected at the background sites, Kangwha, Taean, and Kosan and characterized to understand their behaviors at the sites. Daily samples of PM_(2.5) mass were measured and ionic species, carbonaceous species, and gaseous species were analyzed. Four-daγ backward trajectory analysis was also carried out. The mean concentrations of anthropogenic species were highest at Kangwha among three sites, while contributions from sea salts were highest at Taean during the measurement period due to higher wind speed at Taean. Major chemical components in fine particles were sulfates organic carbon, nitrate, and ammonium. Most of the non-sea-salt (nss) sulfates in PM_(2.5) might be present as ammonium sulfates at these sites. Most air parcels arriving at Kangwha and Taean were from northern China. Therefore, both sites were thought to be affected by the same air parcel. At Kosan, during the measurement period, air parcels were from either northern China or southern China. The nss sulfate concentration in the air parcels from southern China was higher, while the nss calcium nitrate, and ammonium concentrations were higher when the air parcels were from northern China.

Hanger로 보강된 스터드 접합부의 인장거동에 관한 실험적 연구

박휘규,김승훈,이리형,이용택,황홍순,이정희 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)

This paper presents the tensile behavior of the stud connection between reinforced concrete(RC) and steel members. Hanger reinforcements are placed around the studs to transfer the tensile loads to the opposite side of the concrete member. Six specimens, of which variables were arrangement details of hanger reinforcements and studs. Tensile test results show that hanger reinforcements are effective to increase tensile strength and ductility. Test tensile strengths of specimens are compared with the nominal strengths by ACI codes(ACI 318-02, ACI 349-99) and PCI 1999.

우리 나라 배경농도지역의 1996~1997년 미세입자상 탄소성분 측정 결과

김용표,이종훈,문길주,김희강,이종범 江原大學校 附設 環境硏究所 1999 環境硏究 Vol.16 No.-

The concentrations of organic carbon (OC) and elemental carbon (EC) in fine aerosols were determined from the samples collected at the two background sites of Kosan in Cheju Island and Kangwha. Samplings were carried out during the spring and winter of 1996 and the fall and winter of 1997. PM_(2.5) particles were collected on the pre-fired quartz filters for 24 hours and analyzed by the selective thermal oxidation method. The concentrations of OC at the sites were higher than those commonly observed from clean areas around the world, but those of EC at both sites were lower than, or comparable to, other clean areas in the world. Both the OC and EC levels at Kangwha were higher than those at Kosan. According to backward trajectory analysis, most air pollutants collected at thetwo sites were from China. It was found that the OC and EC concentrations in air masses from southern China were higher than those from northern China.

열린 국어교육의 이론과 그 적용

곽재용,이희규 晋州敎育大學校 初等敎育硏究所 1997 初等敎育硏究 Vol.7 No.-

실리콘 웨이퍼 공정용 알루미나 정전척의 제작과 특성에 관한 연구

천희곤,조동율,이영섭,박용균,최성호,정광진,Serguei Spoutai 울산대학교 기계부품 및 소재 특성평가연구센터 1999 연구보고서 Vol.1999 No.-

정전척의 유전체 물질로 열전도도와 유전특성 그리고 기계적 특성이 우수한 알루미나에 TiO₂첨가하여 유전체의 비저항을 변화시켜서 정전척(electrostatic chuck)에서 발생하는 정전력인 쿨롱힘(coulomb force)과 존슨-라벡힘(Johnsen-Fahbeck firce_의 영향을 규명하려 하였다. 그리고 비저항, 인가전압, 온도, 습도가 정전력에 어떠한 영향을 주는지 고찰하였으며, 인가전압에 따른 응답 특성에 관하여 고찰하였다. Alumina electrostatic chucks for silicon wafer process with wide range of electrical resistivity were fabricated by controlling the amount of TiO₂ addition (0 wt%, 1.3 wt%, 2 wt%, 2.8 wt%). The dependence of electrostatic force on applied voltage, temperature and humidity was investigated. In addition, response characteristics on applied voltage and relationship between electrical resistivity and electrostatic force characteristics such as Coulomb force and Johnsen-Rahbeck force were discussed