탄화수소에 의한 NO의 선택적 촉매 환원 반응에서 Pt/MCM-48 촉매의 반응 메커니즘에 관한 연구

양재승,이성철,장재훈,이병용,정석진 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.4

기본형의 Si-MCM-48에 알루미늄 치환량과 귀금속 담지량의 변화에 따라 다양한 촉매를 제조하였고, 이를 탄화수소에 의한 선택적 촉매 환원(HC-SCR)반응에 적용하여 각각의 NO 환원반응 특성을 비교 고찰하였다. Pt/MCM-48 촉매의 NO 환원 활성을 고찰한 결과, 문헌상 보고 되고 있는 Pt/ZSM-5 촉매를 이용한 NO의 제거 활성과 비교하여 매우 우수한 결과를 보였다. 또한 5 vol% 이하의 산소 조건에서 그 활성이 현저하였으며, 특이하게 최고 활성에 도달한 후에 반응온도가 600℃까지 증가하여도 계속하여 그 활성을 유지하였다. XRD, TPD, TGA, XPS 등의 특성화를 통해 촉매의 표면 특성 및 반응 mechanism에 관한 연구를 수행하였으며, 이러한 결과로부터 Pt/MCM-48 촉매가 기존 촉매보다 일정 산소 조건에서 우수한 성능을 보이는 것은 담체의 표면 산특성과 촉매 고유의 redox mechanism에 기인한 것으로 해석하였다. Pt supported on MCM-48 was tested as a new catalyst for hydrocarbon-SCR process. MCM-48 is a new support material of the catalyst for SCR. Characterization and de-NO, activity test were performed for the newly synthesized MCM-48-supported catalysts. Pt(l wt%)/MCM-48 showed 90% of NO reduction at 250-500℃. It should be concluded, from what has been said above, that Pt/MCM-48 catalysts showed higher NO reduction conversion than zeolite based catalyst, and it was not affected by 5 vol% O₂ concentration and water vapor addition. It would be supposed that sustention of activity in that oxygen condition might be caused by surface acidic characteristic and its characteristic redox mechanism.

The Effect of Traditional Market Aid Program on Trust and Support of Marketeer

Yong‐,Ki Lee,Jung Suk Seo,Jae Jang Yang 한국유통과학회 2012 KODISA ICBE (International Conference on Business Vol.2012 No.-

무인계산 게이트용 UHF대역의 RFID 라벨태그 안테나에 관한 연구

이재용,심용석,양진모 대구대학교 정보통신연구소 2010 情報通信硏究 Vol.7 No.1

In this paper, we presented a specific UHF RFID label-type tag antenna for unattended payment gateway system to avoid null point by improving radiation patterns and directivity. The proposed antenna was constructed with form of microstrip line on a thin PET substrate for low-cost fabrication. We built some sample antennas and measured the antenna characteristics such as return loss, radiation patterns, and read range. The operating frequency of the tag antenna is 0.7-1.06GHz under -3dB(VSWR<2) return loss. The average readable range of the tag with a conventional RFID reader is 3.75m and the maximum readable range at an echoic chamber is about 5.68 to 6 m. 본 논문에서는 방사 패턴과 방향성을 향상시켜 널 구역을 제거한 무인 계산 게이트 시스템용 UHF RFID 라벨형 태그 안테나를 제안하였다. 제안된 안테나는 PET 기판에 쉽게 인쇄할 수 있어 제조 단가 절감을 통해 대량 생산이 용이하다. 최적화된 RFID 태그 안테나의 표본 안테나를 제작하고 반사손실, 방사패턴, 인식거리 등을 측정하였다. 태그 안테나의 동작 주파수는 반사손실 -3dB(VSWR<2) 기준으로 0.7-1.06 GHz이며, 고정용 리더시스템을 이용한 태그의 평균 인식거리는 3.75m, 무반사실에서의 최대 인식거리는 5.68-6m였다.

흰쥐에서 말초신경 손상후 뒤뿌리신경절세포의 신경영양인자와 그 수용체의 발현 양상

백선용,양만석,문총석,김봉선,김재봉,김진정 대한해부학회 1999 Anatomy & Cell Biology Vol.32 No.2

RF-MOSFET의 개선된 BSIM3 소신호 모델과 측정기반 파라미터 추출

심용석,김정보,양진모 대구대학교 정보통신연구소 2004 情報通信硏究 Vol.3 No.1

RF 영역에서 동작하는 초미세 MOSFET를 위한 새로운 소신호 모델과 파라미터 추출방법을 제안하였다. 이 모델은 BSIM3v3 코어에 기판 회로망 모델과 기생소자들이 추가된 매크로 모델로 구현되었다. 모델 파라미터들은 공통-소오스로 구성된 다양한 크기와 바이어스 조건하에서 nMOS 트랜지스터의 측정된 S-파라미터로부터 직접 추출되었다. 직접 파라미터 추출은 활성영역에서 동작하는 등가회로에서 Z와 Y 파라미터를 이용하여 임베이딩 기법으로 이루어 졌다. 0.5 GHz에서 20 GHz 범위까지 측정된 S-파라미터와 소신호 모델의 시뮬레이션 결과는 우수하게 일치하였다. A new small-signal model for deep submicrometre MOSFET for radio frequency operation and its parameter extraction method are proposed. The model is implemented as macromodel with substrate network model and parasitic elements added to the BSIM3v3 core. Model parameters are directly extracted from S-parameter data measured from common-source structured and various sized and biased MOS transistors . Direct parameter extraction is performed by embedding technique using Z and Y parameter analysis on the equivalent circuit in the saturation region of operation. Excellent agreement between the simulation results of the small-signal model and measured S-parameters at virious-sized MOS transistor in the range from 0.5 GHz to 20 GHz has been obtained.

흰쥐에서 Cumambrin A의 대동맥 이완작용

홍용근,양민석,박윤배 Plant molecular biology and biotechnology research 2005 Plant molecular biology and biotechnology research Vol.2005 No.

We previously reported that the exogenous administration of cumambrin A, a sesquiterpene lactone from the dried flowers of Chrysanthemum boreale Makino has a pharmacological effect on normalization of blood pressure in the spontaneously hypertensive rats (SHR). In the present study, we further investigated the effect of cumambrin A on the relaxation of phenylephrine-induced precontracted rat aortic artery rings. The potency of cumambrin A was then compared to verapamil, a well known Ca^(2+)-channel blocker. The results demonstrate that the isolated rat aortic arteries are relaxed to basal tension at a concentration of 5X10^(-5)M cumambrin A treatment. The results also show that the phenylephrine-induced contraction is inhibited by a pretreatment of cumambrin A. Co-treatment of cumambrin A and verapamil showed a strong synergetic effect on the relaxation of rat aortic artery rings. Thus, these data demonstrate that cumambrin A is a potent relaxant of rat aortic smooth muscle and suggest that cumambrin A modulates intracellular or extracellular Ca^(2+) mobilization.

생물막여과공정에 의한 고도정수처리시스템 구성에 관한 연구

강용태,양희천,김화석,김경동 동아대학교 환경문제연구소 1999 硏究報告 Vol.22 No.2

This study is to evaluate the characteristics of submerged biofilter process as pretreatment of raw water and alternative advanced water treatment system(AAWTS) composed with bioflitration, post-ozonation and GAC for Nakdong River by comparison of existing advanced water treatment system(EAWS), composed with pre-ozonation, flocculation, sedimentation, sand filtration, post-ozonation and GAC. In the biofiltration process, the removal of turbidity, color, KMnO₄consumption, NH₃-N and UV254 reached 98%, 95%, 70%, 72%, 79% respectively. The stable removal efficiency was obtained by the direct biofiltration after coagulant injection thought the influent was a muddy and highly polluted. The removal efficiency of the alternative advanced water treatment(AAWTS) using biofiltration process for turbidity, color, KMnO₄consumption, NH₃-N and UV254 was reached 98.5%, 98%, 82%, 90%, 92% respectively. It is equivalent to the removal efficiency of existing advanced water treatment system(EAWTS) though the demanded area and coagulant of the alternative advanced water treatment system using biofiltration process was decreased about 60% and 70% respectively.

구강에서 분리한 E.durans의 S.mutans와 S.oralis에 대한 작용

김용남,양규호,오종석,정진 대한소아치과학회 2000 大韓小兒齒科學會誌 Vol.27 No.2

장구균은 사람의 구강, 질, 장내 등에 정상적으로 존재하는 세균이다. 본 연구에서는 구강에서 분리된 장구균중 Enterococcus durans로 동정된 분리균주 4주의 특성과 구강내 주요 세균인 Streptococcus mutans와 Streptococcus oralis와의 관계를 연구하여 다음과 같은 결과를 얻었다. 1.분리균주에 대한 당 발효 검사와 생화학적 검사 결과, 비슷한 양상을 보였다. 2.분리균주 모두 erythromycin, penicillin, tobramycin, ampicillin, teicoplanin, ciprofloxacin, vancomycin, gentamicin, kanamycin 및 streptomycin에 대해 감수성을 보였다. 3.S.mutans를 일회용 큐벧에서 단독 배양시 550 nm에서의 흡광도가 1.405이었으나, S.mutans와 4주의 분리균주 혼합 배양시에는 각각의 흡광도가 0.855, 0.867, 0.797, 1.083으로 감소되었다. 4.비커 와이어 검사 결과, S.mutans 단독 배양시 형성된 인공치태의 평균 무게는 1566 ±103 mg이었다. S.mutans와 4주의 분리균주 혼합 배양시에는 각각 44 ±5 mg, 41 ±12mg, 34 ±7mg, 38 ±12mg으로 현저히 감소되었다. 배양후 생균수는 S.mutans 단독 배양시 ml당 2.0 ×10□이었으나, S.mutans와 4주의 분리균주 혼합 배양시 S.mutans는 2.0 ×10□내지 6.0 ×10□으로 감소되었다. 5.S.oralis 단독 배양시 ml당 2.1 ×10□이었으나, S.oralis와 4주의 분리균주 혼합 배양시 S.oralis는 1.4 ×10□내지 7.0 ×10□으로 감소되었다. 6.3주의 분리균주로 부터 약 60 kb의 plasmid를 분리할 수 있었다. 이상의 결과를 종합하면 구강에서 분리된 E.durans는 S.mutans의 증식을 억제하여 인공치태 형성을 저지하였고, S.oralis의 증식은 약간 억제하였다. 주요어 : Enterococcus durans, Streptococcus mutans, Streptococcus oralis

이동통신 멀티미디어 데이터서비스의 트래픽 특성 모델링 및 성능분석

정용주,백천현,김후곤,최택진,양원석,황흥석 한국경영과학회 2003 한국경영과학회지 Vol.28 No.2

The aim of this study is to identify the data traffic capacity of 3G mobile communication networks, especially of cdma2000-1X networks. Three-layered ON/OFF traffic model is used to describe the dynamics of data traffics and the process of data transmission such as packet scheduling. We construct a simulator fully incorporating packet handling process of cdma2000-1X data network as well as three-layered ON/OFF traffic model describing the behavior of source data traffics. To get influence of traffic parameters on performance measures, the extensive simulations were performed for several data sets which are obtained from real trace data or previous studies. The experimental results show that the engineered throughput satisfying QoS criteria is approximately 20% of total capacity. Finally, some proposals to improve the system capacity are followed.

생체분해성 망막압정을 이용한 망막고정에 대한 실험적 연구

김용백,민병무,김창식,박근성,김승영,길숙종,조항진,이성복,노승무,송규상,강대영,조준식,양준묵,정경수,최선웅,이진호,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

Biodegradable retinal fixation devices obtain mechnical fixation of the retina with desirable chorioretinal scarring and with the potential for local, sustained release of antimetabolites and steroids to inhibit proliferative vitreoretinopathy. We manufactured a biodegradable retinal tack with barb that was designed in order to prevent intrusion from implantation of retinal tacks. This study was carried to evaluate the efficacy for retinal fixation and the capability for sustained release of drugs with a newly designed biodegradable retinal tack Biodegradable retinal tacks were made of polymers of glycolic acids and were designed with barbs in a shape to prevent the disinsertion. Biodegradale retinal tacks are divided into 3 parts, a conical portion that is inserted into the sclera, a cylinder portion that remains in the vitreous, and a neck portion between the pin and the cylinder. The tapered conical end was manufactured to allow easy insertion through the retina and choroid into the sclera. A cylinder portion was manufactured with a tapered angle that fixes firmly into the orifice of 19 gauge spinal needle. A neck portion, 0.4 mm in diameter, was designed to prevent disinsertion from following implantation of retinal tack. The applicator was a 19 gauge spinal needle and its orifice was prepared to 15°angle to accept the tapered cylinder portion of the retinal tack. The retinal tacks, secured in the needles, were passed through the formed vitreous and inserted into the retina, choroid, and sclera and were released by pushing the internal needle, usually within 2-3mm of the medullary ray of the posterior rabbit retina A retinal tack was placed in each of 8 pigmented rabbit eyes. Slit-lamp biomicroscopy, indirect ophthalmoscopy and fundus photography were performed periodically from 1 day to 8 weeks after surgery. Eight eyes were enucleated and studied by light microscopy at 8 weeks. Biomicroscopic evaluation of the animals revealed edemas adjacent to the retinal surfaces immediately after insertion of the biodegradable retinal tacks in all the animals. These edemas disappeared after 1 week. The first noticeable change in the size of retinal tacks was shown after 2weeks. The size of the retinal tacks gradually got smaller, decreasing to about one-half at 4 weeks and about one-third at 8 weeks. All retinal tacks remained in inserted places without any movement for an 8 week period. On light microscopy, epiretinal proliferations were seen to extend into the vitreous cavity. Cellular capsules that lined the inner aspect of the scleral defect caused by tack insertion were found. However the adjacent retina had a normal cytologic appearance and architecture in all specimens. We manufactured a biodegradable retinal tack that is designed to prevent intrusion from implantation of retinal tacks. All biodegradable retinal tacks reduce in size with time, but no retinal tacks extruded from the inserted place. The newly designed biodegradable retinal tack can be used for retinal fixation and may be used as a vehicle for the introduction of pharmacologic agents to prevent the cellular events that promote proliferative vitreoretinopathy.