Rayleigh-Ritz법에 의한 단순지지된 타원형판의 고유진동수

강재훈,이은택,장경호 중앙대학교 건설산업기술연구소 2000 건설산업기술연구소 논문집 Vol.1 No.-

The problem of free vibration of a simply-supported elliptical plate has no published results in the literature. The present work uses the Rayleigh-Ritz technique with a three-term deflection function to obtain accurate fundamental frequencies. Tabulated results are given for the complete spectrum of Poisson's ratios and aspect ratios.

유사성 계수에 관한 연구

강경식,오영수,나승훈,김태호 명지대학교 공학기술연구소 1992 공학기술연구소 논문집 Vol.7 No.-

본 논문은 재공품 재고를 줄이기 위한 방법으로서 유사성 계수법의 도입에 관하여 서술하였다. 특히 J.R.King의 이론과 Nakornchai의 ROC-2 이론을 비교 하였다. 그 결과로서 ROC-2의 이론은 적은 기계 혹은 부품에서와 같은 시스템에 사용하는 것이 유리하며 또한 기계나 부품의 그룹화가 서로 독립적으로 수렴되지 않아도 된다는 장점이 있다. This paper reprented that work-in-process inventory has been decreased with the application of the similarity coefficient algorithm. Especially, J.R.King's ROC and Nakornchal's ROC-2 algorithm is studied. The analyzed resuits in this paper are as ROC and ROC-2 algorithm have an adventage that it can be used in production system which has many machinary and component and an arbitrary threshold value should be define and many grouping are being performed independently.

직무분석을 이용한 스포츠 시설업 경영관리자 교육과정 개발

강호정,김경식 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.4

Entry into the information era is bringing many changes in the field of sport that the era just pushed sport in to the market driven area, As a result, there has been a rapid increase in interest and investment in the sport industry, The sport facility industry as one sub-industry of sport industry occupied 37.2% of total of sport industry in 2001. The increase in sport participation, increase of national income, reduction of labor time, pursuit of quality of life have increased the number of sport facilities and personnel related to sport facilities. In order to come up with the change of enviornment, it is necessary to educate new theories and practices about management of sport facility for personnel related to sport facilities. The purpose of this study was to develop of educational program for sport facility manager on the basis of job analysis and survey on employees who were educated, There are two educational programs(practice, strategy) for sport facility manager. Through this educational program, it is possible to secure excellent human resource which is a drive of growth for sport facility.

전자빔으로 전처리한 제지폐수의 처리특성

신경숙,박재규,강호 忠南大學校 環境問題硏究所 1998 環境硏究 Vol.16 No.-

Treatability test for paper-mill wastewater pretreated with electron beam irradiation was investigated using the activated sludge simulation. The dose of electron beam irradiation exposed to paper-mill wastewater was relatively low(1kGy). The results showed that the BOD/CODCr of irradiated paper-mill wastewater increased up to 0.45 from 0.36 of unirradiated one. This was due to the conversion of nonbiodegradable organics to biodegradable ones by electron beam exposure. For the activated sludge systems operated at the various HRTs, BOD removal efficiency and COD removal efficiency of both reactors were similar. As a tool of sludge bulking measurement, sludge volume index(SVI) of activated sludge system operated with irradiated paper-mill wastewater was found to be lower (about 210∼ 241㎖/g)than that with unirradiated paper-mill wastewater(about 249∼298㎖/g). Biokinetic constants derived from Ekenfelder's modified model appeared 8.72/day for the irradiated paper-mill wastewater and 4.95/day for the unirradiated paper-mill wastewater, respectively. From the above results, it concluded that the pretreatment of paper mill wastewater with electron beam irradiation could improve the biodegradability as well as sludge activity even with the relatively low dose of electron beam irradiation.

폴리피롤이 함유된 PVdF-HFP/PVP를 이용한 Supercapacitor용 복합전극의 전기화학적 특성

오호성,김경민,강안수 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.6

전도성 고분자인 폴리피롤을 5-8 wt% 첨가한 활성탄(BP-20 및 YP-17)에 Poly (vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP)/pelyvinylpyrrolidone(PVP)의 혼합결합제를 n-methyl-2-pyrrolidinone(NMP)에 용해시켜 복합전극을 제조하였다. 단위셀의 충·방전 특성, 비정전용량, AC-ESR, 에너지밀도, CV 및 impedance 특성 등의 전기화학적 특성을 측정하였다. 혼합결합제를 5 wt%로 고정하였을 때 전극의 유연성, 높은 기계적 강도 및 우수한 전기화학적 특성을 갖는 전극을 제조하기 위하여 폴리피롤의 무게합량이 8 wt% 이내로 첨가하는 것이 적당하였다. 특히, BP-20의 전극에 첨가된 폴리피롤의 무게함량이 7 wt%일 때 전극의 비정전용량 34.77 F/g, AC-ESR 0.65 Ω, 에너지밀도 8.16 Wh/kg 및 동력밀도 1,830 W/kg으로 상용화된 제품보다 우수하였고 Ragone plot 상에서 볼 때 전기자동차에 적용할 가능성을 볼 수 있었다. Composite electrodes were fabricated based on activated carbons such as YP-17 and BP-20, and conducting polymer of polypyrrole (pPy) prepared by chemical polymerization in our laboratory. Mixed binders of Poly (vinylidene-fluoride-co- hexafluoropropylene) (PVdF-HFP) and polyvinylpyrrolidone (PVP) in n-methyl- 2-pyrrolidinone (NMP) were added to the activated carbons. Electrochemical characteristics of unit cells such as charge-discharge, specific capacitance, ESR, specific energy, cyclic voltammetry (CV) and impedance were measured. It was noted that a pPy content within 8 wt. % greatly increased the electrochemical characteristics, mechanical strength and flexibility with the fixed 5 wt. % of mixed binder. Especially, the BP-20 electrode with 7 wt% of pPy exhibited better electrochemical characteristics than commercialized products, with 34.77 F/g of specific capacitance, 0.65Ω of AC-ESR, 8.16 Wh/㎏ of specific energy, and specific power of 1,830 W㎏. Power outputs were compatible with electric vehicle applications, in due consideration of Ragone relations.

일부농촌지역의 농약사용실태 및 농약중독 요인 조사

이경민,송주희,장재혁,심수정,강양화,안재경,이숭호,박미영,정문호 대한보건협회 2002 대한보건연구 Vol.28 No.4

Object The usage of agricultural chemical is on the increasing. Use of pesticides has increased agricultural production. However, negative externalities from such use have increased too. Pesticide poisoning is a major public problem. The purpose if this study is to find out the relationship between keeping the safety rules or protective equipments or attending safety education or dose of pesticides use , and poisoning experience. Methods For Gu, H.M. and Pack, S.G. study , we obtained questionnaire data concerning pesticides poisoming. A person interviews on 203 were conducted in two villages in Sinmeari and woulbonri Chunchun , Kangwon province, July 2002. Result 1. 144 people(70.9%) have sprayed pesticides and the rata of experiences of pesticide poisoning was 26% among 144. Spraying time of pesticides was 1-2 hours in 63.9% of farmers. Rate of using the protective equipment was 25.7% (protective clothes), 49.3% (Mask), 48.6 (Gloves), 7.0 (Protective glasses), 64.6% (boots) respectively. 2. Chi-square and multiple logistic regression analysis showed that Duration of spraying per day (<2hr) and using of mask(protective equipment)are significantly association with poisoning experience.(x^2=5.2684 p=0.0217, CI=0.140-0.5853 OR=0.346 p=0.0211 respectively). But no association between poisoning experience and keeping safety rule, attending of safety education. 3. Spraying pesticides. Duration of spraying pesticides, reading manuals and no spraying at fatigue (keeping safety rule) are significantly association with symptom experience(x^2=14.0621 p=0.0002, x^2=7.0639 p=0.0079, CI01.395-10.950 OR=3.908 p=0.0095, CI=0.101-0.726 OR=0.271 0.0094 respectively). But no association between symptom experience and protective equipments, attending of safety education.

전자빔조사가 염색폐수의 처리에 미치는 영향평가

신경숙,강호 忠南大學校 環境問題硏究所 1999 環境硏究 Vol.17 No.-

Treatability test for dyeing wastewater pretreated with electron beam irradiation was investigated using the activated sludge simulation and chemical coagulation. The does of electron beam irradiation exposed to dyeing wastewater was relatively low(lkGy). The results showed that the BOD/COD?? of irradiated dyeing wastewater increased up to 0.83 from 0.71 of unirradiated one. This was due to the conversion of nonbiodegradable organics to biodegradable ones by electron beam exposure. For the activated sludge systems operated at the various HRTs, BOD removal efficiency with the irradiated dyeing wastewater is appoximately 10% higher than that with the unirradiated dyeing wastewater at an HRTs of 16hrs. COD removal efficiency of the reactor operated with the irradiated dyeing wastewater is also about 20% higher than that of the reactor operated with the unirradiated wastewater at an HRTs 16hrs. Biokinetic constants derived from Ekenfelder's modified model appeared 3.28/day for the irradiated dyeing wastewater and 1.45/day for the unirradiated dyeing wastewater, respectively. The optimum connditons for coagulating dyeing wastewater with FeCl₃was found to be at pH 4.0 and its dose of 1500㎎/ℓ, while with Al₂(SO₄)₃at pH 4.6 and 1200㎎/ℓ. The coagulation efficiency with irradiated dyeing wastewater resulted in 15% higher than that with unirradiated dyeing wastewater. From the above results, it concluded that the pretreatment of dyeing wastewater with electron beam irradiation could improve the biodegradability as well as the overall treatment efficiency even with the relatively low dose of electron beam irradiation.

Regulatory Roles of Chrysanthemum zawadskii Roots in Nuclear Factor E2-related Factor 2/Antioxidant Response Element Pathway

Hye-Sook Kang,Min-Ji Park,Kyong-Suk Jin,Young-Hun Kim,Mira Jun,Ho-Jin Lim,Wan-Kuen Jo,Jong-Sang Kim,Woo-Sik Jeong 한국식품과학회 2008 Food Science and Biotechnology Vol.17 No.2

Cellular protection against carcinogens could be achieved by the induction of phase 2 detoxifying and antioxidant enzymes such as glutathione S-transferase (GST), NAD(P)H:quinone oxidoreductase 1 (NQO1) and heme oxygenase 1 (HO-1). Nuclear transcription factor E2-related factor 2 (Nrf2) binds to antioxidant response element (ARE) in the promoter region of these genes and the resulting transactivation occurs. In the present study the effect of gujeolcho (Chrysanthemum zawadskii) roots on the Nrf2-ARE pathway were investigated. C. zawadskii root extract was fractionated with a series of organic solvents and their ability to induce Nrf2-ARE pathway was examined. We separated the most potent dichloromethane (DCM) fraction into 12 sub-fractions and found several sub-fractions with strong effects on the Nrf2-ARE pathway. Fraction 4 strongly induced the ARE-reporter gene activity as well as Nrf2 expression. Sitosterol was isolated as a major compound in fraction 4 although its activity was not as potent as its mother fraction. These results indicate that C. zawadskii roots might be used as a potential natural chemopreventive source.

AISC-LRFD 규준을 이용한 기둥설계에서의 강성감소계수

이은택,강재훈,장경호 중앙대학교 건설산업기술연구소 2000 건설산업기술연구소 논문집 Vol.1 No.-

The design of columns in ordinary construction involves slenderness ratios KL/r in the inelastic bucking range. When the alignment chart is used to evaluate K there is an important that elastic buckling controls. When the column is inelastic and the beam is elastic, and adjustment may be made in the restraint factor G used in the alignment chart. It is well known that when using the standard alignment charts to determine the effective length factor K of a column, the restraint factors G should reflect the inelastic behavior of the column. The stiffness reduction factor (SRF's) given in Table A of the AISC-LRFD manual has an error that needs to be corrected. The error occurs in adopting the technique originally proposed by Yura in the context of AISC-ASD to AISC-LRFD. In estimating the SRF in a design problem, Yura assumed that the column is designed very close to its capacity. In this study, the stiffness reduction factor for AISC-LRFD specification of columns are evaluated and corrected. The procedure of calculating the siffness reduction factor is also introduced.

Implication of necrosis-linked p53 aggregation in acquired apoptotic resistance to 5-FU in MCF-7 multicellular tumour spheroids

Lee, Su Yeon,Jeong, Eui-Kyong,Jeon, Hyun Min,Kim, Cho Hee,Kang, Ho Sung Spandidos Publications 2010 Oncology reports Vol.24 No.1

<P>Three-dimensional (3D) multicellular tumour spheroids (MTS) have been used as an in vitro model of solid tumours for drug resistance studies because they mimic the growth characteristics of in vivo tumours more closely than in vitro two-dimensional (2D) culture of cancer cell lines. As observed in solid tumours, MTS exhibits a proliferation gradient with outer regions consisting of proliferating cells that surround inner quiescent cells. The innermost cells in core regions undergo cell death mostly by necrosis to form necrotic core due to insufficient supply of oxygen and nutrient such as glucose with increasing size of spheroids. Tumour necrosis is thought to indicate a poor prognosis and to contribute to acquisition of chemoresistance in solid tumours; however, the mechanism underlying necrosis-mediated chemoresistance remains unclear. In this study, we examined the chemoresistance to 5-Fluorouracil (5-FU) using MCF-7 breast cancer MTS. 5-FU (400 microM) induced apoptosis in MCF-7 cell monolayer as determined by HO/PI staining, PARP cleavage, p53 induction, Bax induction, and Bcl-2 down-regulation. When MCF-7 breast tumour spheroids were cultured on agarose for 8 days, they reached approximately 700 microm in diameter, with a necrotic core. We found that 5-FU-induced apoptosis is markedly reduced in spheroids that were cultured for 9 days and had necrotic core, compared with MCF-7 monolayer cells and spheroids that were cultured for 6 days and had no necrotic core, indicating that the formation of necrotic core may be linked to acquisition of chemoresistance to 5-FU. We also found that a specific set of cellular proteins including p53 was aggregated into a RIPA-insoluble form during MTS culture. Furthermore, most of p53 induced by 5-FU was aggregated in MTS with necrotic core. Our results suggest that necrosis-linked p53 aggregation may contribute to acquired apoptotic resistance to 5-FU in MTS model system.</P>