Fatigue Crack Growth Behavior in Ultrafine Grained Low Carbon Steel

Ho,Kyung Kim,Myung-Il Choi,Chin-Sung Chung Dong-Hyuk Shin 대한기계학회 2002 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.16 No.10

Ultrafine grained (UFG) low carbon (0.15 wt.% C) steel produced by equal channel angular pressing (ECAP) was tested for investigating the effect of load ratio on the fatigue crack growth rate. Fatigue crack growth resistance and threshold of UFG steel were lower than that of as-received coarse grained steel. It was attributed to the less tortuous crack path. The UFG steel exhibited slightly higher crack growth rates and a lower △K_th with an increase of R ratio. The R ratio effect on crack growth rates and △K_th was basically indistinguishable at lower load ratio (R>0.3), compared to other alloys, which indicates that contribution of the crack closure vanishes. The crack growth rate curve for UFG steel exhibited a longer linear extension to the lower growth rate regime than that for the coarse grained as-received steel.<br/>

컴퓨터 법에 있어서의 책임에 관한 연구

鄭鎭世,鄭在晃,方碩皓,河泰勳,李成德,崔鳳哲 홍익대학교 1995 弘大論叢 Vol.27 No.-

This paper, coauthored by Chin-Se Chung, as well as other 5 faculty members at Hong-Ik University Department of Law (Jea-Hwang Jeong, Suk-Ho Bang, Tae-Hoon Ha, Seong-Deog Yi and Bong-Chul Choi), deals with liability issuses surrounding constitutional law, administrative law, civil law (contracts, torts), commercial law, criminal law, international law and philosophy & law. Professor of Law Jea-Hwang Jeong makes a comparative analysis of privacy protection and disclosure of information legal issues, appeared at current Korean law and draft of law in case of the latter one. He suggestes some desirable ways of legislation through revision process and operation of legal rules at his paper. Professor of Law Suk-Ho Bang makes a brief survey of civil liability issues arising out of contracts and torts in English and American law, first. He tries to show that many Parts of arguments in such legal world are attributed to Statute of Frauds tradition, unique to such legal world. New developments in the area of torts, including computer malpractice and computer virus, are shown and analysed in terms of application possibility under our current law. But, as even the Anglo-American courts are found very reluctant to accept those arguments as new grounds for torts liability, it seems more plausible and practicable to refer to contractual approach, basically, rather than to torts approach even under English American law. Professor of Law Chin-Se Chung suggests in his paper on EFT that the allocation of liability under EFT be made under the new and most relevant principle, working for useful transmission way of fund, not solely under traditional legal principles. If such new principle works with high return of risk to users, it makes imminent problems against the goats of consumer protection, and eventually will be hardly refered to. Conversely, if it requires too much sacrifice from the side of banks, then the convenience in such system will not be utilized. So, it may be natural that EFT be discarded even without proper functioning under market system. In conclusion, Professor Chung points out that, only when banks fond that the economy out of cost-saving at tasks outweighs the risk undertaken by the banks, the banks will operate the system. But, if this system makes more return of benefits to the banks with the burden of users, it is against the idea of equity. Consequently, the banks should bear the aggeviated risks in return for the cost saved under this system Professor of Law Tae-Hoon Ha focuses his research paper on criminal liability under EFT. He draws his conclusion out of current criminal statutes that illegal fund transfer under automatic teller machines, cash cards and information system can not be penalized due to lack of proper statutory provision. So, the criminal provision on computer crime, newly made on December of 1995, can be positively appreciated. But, he anticipates that the question whether such new provision will be successful in regulating all illegal activites at fund transfor system without any operation defects in criminal code, or will cause new problem in interpretation of criminal code remains unsolved. Professor of Law Seong-Deog Yi examines the international legal issues which may be given rise to by direct satellite broadcasting. In his paper, the issue of national jurisdiction in relation to direct satellite broadcasting is firstly dealt with. Secondly, the possible ways in which direct satellite broadcasting is regulated by international law are examined with special emphasis of two different approaches, that is, freedom of information approach and state sovereignty approach. In this context, many international conventions concerning direct satellite broadcasting in Particular, and international regulatory regime of outer space in general are broadly reviewed. Thirdly, the types of activities which may be a violation of international legal regime of direct satellite broadcasting are suggested and the possible lethal remedies for these violations are proposed with the traditional international state responsibility law in mind. Professor of Law Bong-Chul Choi explores the relations of computerized society to its laws throughout his paper as a kind of conclusion of this whole paper. Computerized society is one that the technical, scientific, informational knowledge prevails. With correspondence to the structural change in knowledge, the law of such a society has suffered transformation, and the knowledge and techniques distributing and computing legal responsibility has also changed. However, he does not insist that the diffusion of technical knowledge is the sole factor of the transformation of legal responsibility. It is only one of the various factors. Moreover, he does not deny the continuation between the classical techniques distributing legal responsibility and the contemporary ones. In this era, the law realizes fairness and community values at the expense of singularities. In addition, he proposes that legal scholars take the diagnosis of law from the perspective of the technology/knowledge shifts seriously.

Effects of 17β-estradiol on colorectal cancer development after azoxymethane/dextran sulfate sodium treatment of ovariectomized mice

Song, Chin-Hee,Kim, Nayoung,Lee, Sun Min,Nam, Ryoung Hee,Choi, Soo In,Kang, So Ra,Shin, Eun,Lee, Dong Ho,Lee, Ha-Na,Surh, Young-Joon Elsevier 2019 Biochemical pharmacology Vol.164 No.-

<P><B>Abstract</B></P> <P>Estrogen is known to have a protective effect in colorectal cancer (CRC) development. Previously, we reported the anti-inflammatory and antitumorigenic effects of 17β-estradiol (E2) in azoxymethane (AOM)/dextran sulfate sodium (DSS)-treated male mice. The aim of this study was to investigate whether ovariectomy in a female AOM/DSS mouse model increases colorectal tumorigenesis and whether tumorigenesis is reduced by estrogen supplementation after ovariectomy. Clinical symptoms and histological severity of colitis and the levels of inflammatory mediators were evaluated in the colon of AOM/DSS-treated ovariectomized (OVX) mice. The levels of E2, myeloperoxidase (MPO), and NF-κB-dependent cytokines (interleukin (IL)-1β and IL-6) were measured by ELISA. Furthermore, quantitative real-time (qRT) PCR and Western blot analysis were performed. Ovariectomy did not aggravate AOM/DSS-induced colitis at 2 weeks. At weeks 10 and 16, ovariectomy significantly increased tumor number and incidence rate in only the proximal colon after AOM/DSS treatment (F_AOM/DSS vs OVX_AOM/DSS), and these increases were significantly reduced by E2 supplementation (OVX_AOM/DSS vs OVX_AOM/DSS/E2). However, ovariectomy did not affect CRC development in the distal colon (F_AOM/DSS vs OVX_AOM/DSS). At week 2, E2 administration to AOM/DSS-treated OVX mice attenuated the histological severity of colitis by decreasing the protein and/or mRNA levels of estrogen receptor alpha (ERα) and NF-κB-related mediators (i.e., COX-2, TNF-α, and IL-6) and by enhancing estrogen receptor beta (ERβ) and nuclear Nrf2 protein expression and the mRNA expression of related antioxidant enzyme genes (i.e., HO-1, GCLC, GCLM, and NQO1). Endogenous estrogen in females protects against the development of proximal colon cancer, and exogenous E2 replacement in OVX female mice showed protective effects against AOM/DSS-induced colitis and carcinogenesis. The mechanism could involve modulating ERs-, NF-κB- and Nrf2-mediated pathways.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

초과포지션과 스프레드

김희호(Hee Ho Kim),김석진(Seok Chin Kim) 한국경영학회 2006 經營學硏究 Vol.35 No.1

Spread is defined as a difference between ask and bid rates for a specific currency in the foreign exchange (FX) market. The spread reflects the transaction costs as well as the exchange risk. Its change is interpreted as signal of the information changes on the efficient market. Even though its growing importance in the market, many studies have not focused on the spread either because the spread is believed to be a kind of transaction cost or because it practically determined in the market.Inventory holding cost of spread was studied by many researchers such as Demsetz(1968),Ho?Stoll(1981), Stoll(1978), and Bollen?Smith?Whaley(2004). As exchange volatilities increase, the spread tends to increase and the expected loss gets greater by exchange risk against holding a foreign exchange inventory. According to Demsetz(1968), the inventory holding cost is a compensation for guaranteeing immediacy of transaction to the customers. A dealer would take the position asked by a seller if that position was not completely traded. The dealer takes exchange risk with that position in return for spread. The immediacy depends on the time interval taken in a transaction during which a position is completely offset.The shorter time interval will not cause much exchange risk and, thus, the less inventory holding cost. Th spread is stochastic, as such is the time interval of transaction. The previous studies are based on two important assumptions; a risk neutral dealer and non-trivial time interval. The development in internet and information technology, however, eliminates the time interval of transaction and result in the immediacy of transaction in the FX market. Spread does not reflect the inventory holding cost anymore and is not a compensation for the immediacy of transaction. Taking this recent market development into account, this paper proposes two different assumptions from the previous ones; no time interval of transaction and a risk averse dealer.Under these two assumptions, spread does not count on the uncertainty of time interval, but on the uncertainty of excessive position brought about by immediate transaction. An important emphasis shifts over from time dimension to volume dimension in determining spread. A main channel through which the undesired inventory affects spread depends on the risk aversion degree of dealer and variance of the undesired inventory in the FX market. The undesired position tends to deviate a dealer’s portfolio balance from his optimal balance and thus decreases his expected utility, otherwise maximized. Spread would compensate for a dealer’sexpected loss of utility caused by the undesired position.This study develops a theoretical model to examine the effect of undesired excessive position on the spread. We provide the simulation results by exploring how differently the probability of undesired excessive position influence the spread in the market. We test spread as dependant of undesired excessive position and its volatilities.Using GARCH(1,1) method and the daily data of the Korean Won/U.S. Dollar exchange rate from a market leading dealer during January 2-June 29, 2004, evidence provides a strong support for our theory. It is shown that the undesired excessive position and its volatilities have an significant impact on the spread in the Korea FX market. Actually realized volume of transaction does not seem to affect the spread, though. Taking data of futures trading as a proxy for undesired excessive position, the evidence was not statistically significant in explaining spread changes.This empirical result seems to be in sharp contrast to those of the previous studies. The relationship between trading volume and spread seems to vary across the markets. We skip over the effect of dealer’s pricing strategy on spread because it goes beyond the scope of our study. A study on the effect of dealer’s pricing strategy is remained for a future research.

테라조 타일 제조시 발생되는 슬러지의 기본특성과 활용방안 연구

진호일 강원대학교 부설 석재복합신소재 제품연구센터 2002 석재연 논문집 Vol.7 No.-

테라조 타일 제조시 발생되는 슬러지는 주로 방해석과 백운석, 석영 등의 광물로 이루어져 있으며, 참비중은 2.7, pH는 11.6으로 강알카리성을 보였으며, 대부분 미사질의 입도로 이루어져 있다. 테라조 슬러지는 토양환경보전법에서 설정한 Cu, Pb, Cd, Cr, As, Hg 등 6가지의 중금속 원소들이 모두 기준값 이하의 낮은 용출 함량값을 보여 토양오염 수준에 훨씬 못 미치고 있는 것으로 나타났다. 테라조 슬러지에 대한 물리적·화학적 특성을 고려할 때 연구대상 테라조 슬러지는 산성토양을 중화시키는 토질개량제나 복토제 및 석회질 비료, 산성광산배수(AMD)를 중화시키는 중화제로도 이용 가능할 것으로 판단되며, 석산에서 발생되는 석분슬러지와 9:1∼8:2의 무게비로 배합·성형하여 600℃로 열처리한 성형체를 폐광산의 갱도에 충진시킬 경우에는 지반침하 방지뿐만 아니라 폐갱도로부터 유출되는 산성배수를 중화시킬 수 있는 효과가 충분히 있을 것으로 생각된다. The sludges from manufacture of terazzo tiles were mainly composed of calcite, dolomite and quartz, and their true specific gravities and pH's were 2.7 and 11.6, respectively, and mostly consisted of silt size grains. The terazzo sludges have less leaching contents than standard levels established in Soil Environment Conservation Regulation on six heavy metal elements (Cu, Pb, Cd, Cr, AS and Hg), which suggest that such heavy metals be not contaminated. With their physical and chemical properties. the terazzo sludges could be utilized as modifier of soil nature, overburdening soil, calcareous fertilizer and neutralizer of AMD. Some specimens after heat treatment at 600℃ for two hours with mixing ratio (stone powder sludges : terazzo sludges = 9 : 1 ∼ 8 : 2, by weight ratio) showed their potential utilization as filler of waste pit to prevent ground subsidence.

저에너지 전자 회절실험에서의 전자선 입사각계산

진원배,이두일,류호창 東亞大學校 1996 東亞論叢 Vol.33 No.-

A computer program for determining the angles of incidence in a low energy electron diffraction (LEED) experiment is written which uses the angles between the diffraction spots on a photograph of LEED pattern measured by Stephen L. Cunningham and W. Henry Weinberg. The results determined by using our program are in good agreement with those of Stephen L. Cunningham and W. Henry Weinberg within the extent of 0.1" in the polar angle and 0.01" in the azimuthal angle.

악교정 수술후 발생한 감염 4증례

진병로,김종섭,박진호,이창곤,박희대,이희경 大韓顎顔面成形再建外科學會 1995 Maxillofacial Plastic Reconstructive Surgery Vol.17 No.1

Postoperative infection following orthognatic surgery is rare. When postoperative infections occur, the initial treatment consists of incision and drainage of the affected area, culturing to identify bacterial stains and verify antibiotic sensitivity, and the institution of the appropriate antibiotic regimen. Some plates and screws may eventually require removal, the initial therapy should be attempted to retain the plates and screws until adequete healing has taken place. In orthoganthic surgery, intra-operative complications as a lesion of inferior alveolar nerve, fracture of osteomised segments, incomplete sectioning, malposittion of segments, haemirrhage may occur. The surgeon should be familiar with possible complications to be caused and how to manage them. Prevention of postoperative infection following the orthognathic surgery consists of minimal periosteal reflection, aseptic management of operation field, proper surgical technique, rigid fixation, prophylactic antibiotics.

석분 슬러지를 이용한 중금속 흡착제 개발에 관한 연구

진호일 강원대학교 부설 석재복합신소재 제품연구센터 2000 석재연 논문집 Vol.5 No.-

이 연구는 석산 및 석가공업체 주변의 석폐기물로 발생되는 석분슬러지를 각종 산업 폐수중에 함유되어 있는 Pb, Cu, Zn 등의 중금속을 제거하기 위한 흡착제로 활용할 수 있는 지의 가능성을 모색하였다. 석산에서 발생하는 석분슬러지(IS-01)는 Pb의 경우 15분, Cu는 2시간, Zn은 48시간의 흡착 반응시간과 폐수의 초기 pH는 3이상, 흡착제와 폐수와의 비가 0.02인 조건에서 가장 흡착능력이 좋은 것으로 나타났다. 석가공장에서 발생하는 석분슬러지(CW-01)는 Pb만이 12시간의 흡착반응시간과 폐수의 초기 pH는 3이상, 흡착제와 폐수와의 비가 0.02인 조건에서 비교적 적은 흡착능력을 보였고, Cu와 Zn는 오히려 탈착되는 경향을 나타내었다. 석산에서 발생하는 석분슬러지가 석가공장에서 발생되는 석분슬러지보다 전반적으로 우수한 흡착능력을 보여 주었으며, 중금속 흡착제로서의 활용 가능성이 충분히 있을 것으로 판단된다. This study has been performed to evaluate the possibility of utilizing stoone powder sludges from stone quarry and manufacturing plant as adsorbents for heavy metals in industrial wastewater. The stone powder sludges from stone quarry(IS-01) have the most excellent adsorption capacity under the given experimental conditions of reaction times(Pb:15min, Cu:2hr, Zn:48hr), initial acidity of solution(pH>3) and dosage(sludge/liquid ratio:0.02). The stone powder sludges from manufacturing plant(CW-01) show relatively high adsorption capacity only for Pb with a reaction times of 12hours but reversely desorption characteristics for Cu and Zn. The stone powder sludges from stone quarry of relatively high absorption capacity show their potential utilization as heavy metal adsorbents.

금속광산 주변 광미의 활용을 위한 중금속 원소의 제거 및 고정화

진호일 강원대학교 부설 석재복합신소재 제품연구센터 2002 석재연 논문집 Vol.7 No.-

이 연구는 금속광산의 광미를 활용하기 위해 광미의 제반특성과 광미중 중금속의 제거와 고정화 방안을 모색하였다. 은치와 석담광산의 광미는 각각 참비중이 3.3, 2.7, pH는 모두 3.0의 강산성을 나타내었으며, Cu, Pb, Zn, As 등이 심하게 오염되어 있다. 이러한 광미를 대상으로 중금속의 제거 및 고정화 실험을 수행한 결과 900℃에서 1시간동안 열처리했을 때 Cu, Pb 등 중금속 원소들의 용출함량이 유해함량 기준값보다 훨씬 낮아 중금속의 제거효과가 우수하였다. 또한 은치광산의 광미는 광미와 탄산칼슘의 무게비를 1:1로 하고 이들에 대한 수지의 양을 22 wt%로 하였을 때, 석담광산의 광미는 광미와 탄산칼슘의 무게비를 9:1로 하고 이들에 대한 수지의 양을 20wt%로 할 경우에 Cu, Pb, Cd, Zn, Mn, Fe, Al 등의 중금속을 고정화시키는 효과가 우수하였을 뿐만 아니라 건설소재로서의 물리적·역학적 특성을 가지고 있어 건설재료용 폴리머 복합소재로 사용될 수 있는 가능성이 충분히 있을 것으로 생각된다. For utilizing tailings which were distributed widely in the metal mines, their general properties and devices for removal and fixation of heavy metals were grouped. The tailings from the Eunchi and the Sukdam mines showed true specific gravities of 3.3 and 2.7, respectively, and strong acidic pH's of 3.0, all together, and higher abundances of Cu, Pb, Zn and Cd. Sintering of tailings at 900℃ for one hour showed their leaching contents of heavy metals(Cu and Pb, especially) far less than standard noxious levels. Fixation effect of heavy metals (Cu, Pb, Cd, Zn, Mn, Fe and Al) was most excellent in case the weight ratio of tailing versus calcium carbonates was 1:1 with 22 wt% resin amount for the tailings from the Eunchi mine and 9:1 with 20wt% resin for the Sukdam mine respectively. Also utilization of tailings from metal mines as polymer composite materials is expected in various usage, because of their excellent physical and mechanical properties in those mixing types.

신경회로망과 Classifier를 이용한 부분방전패턴의 인식

李峻昊,李鎭雨 湖西大學校工業技術硏究所 1999 工業技術硏究所論文集 Vol.18 No.-

In this work, two approaches were proposed for the recognition of partial discharge patterns. The first approach was neural network with backpropagation algorithm, and the second approach was angle calculation between two operator vectors. PD signals were detected using three electrode system: IEC(b), needle-plane and CIGRE method Ⅱ electrode system. Both of neural network and angle comparison method showed good recognition performance for the pattern similar to the trained patterns. And the number of operators to be used had a great influence on the recognition performance to the untrained patterns.