파랑에 의한 연안 해수유동의 수치해석 연구

김재중,이정만 東亞大學校 海洋資源硏究所 1996 硏究論文集 Vol.9 No.1

A finite difference model for predicting time-dependent, wave-induced nearshore circuration is discussed. The model includes wave refraction, wave-current iteraction, bottom friction, wind effect and lateral mixing. This model iteratively solved the linear set of conservation of both mass and momentum, which were time averaged (over one wave period) and depth integrated, for mean velocities and free surface displacement. Numerical simulations of nearshore circulation under oblique wave attack on a longshore periodic beach are carried out. Longshore velocities tend to zero in some distance outside of the breaker line. And the peak velocity shifted shoreward at the breaker line. Nearshore circulation is shown by unit cell formation which is due to wave and wave induced current. The results represent the general characteristics of the nearshore circulation induced by wave.

불규칙파의 굴절에 관한 연구

김재중,김철현,김영의 동아대학교 건설기술연구소 1996 硏究報告 Vol.20 No.1

The concept of wave spectrum which represents the random characteristics of waves is introduced and analyzed in this study. Also time series analyses are done by using numerical model that computes the random wave transformation in the nearshore region. The characteristics of shoaling and refraction of random waves which is incident on the straight shorelines with parellel bottom contours are studied using the stecturm analysis. JONSWAP spectum in the deep water depth was converted into TMA specturn in the shallow water detph. TMA spectrum computes the spectrum of wind waves in finite water depth as a funtion of frectrum. This study way be helpful to determining the representative wave height and period for the random deseign waves of coastal structures in the shallow water.

중합효소연쇄반응법을 이용한 급성 치수 및 치근단 질환의 병원성 세균의 동정

김지훈,유소영,임선아,국중기,임상수,박슬희,황호길 大韓齒科保存學會 2003 Restorative Dentistry & Endodontics Vol.28 No.2

The purpose of this study was to investigate the frequency of 7 putative pathogens in endodontic infections. The specimens were collected from infected pulpal tissue of patients who were referred for root canal treatment to the department of conservative dentisty, Chosun University. Samples were collected aseptically using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing 500 ml of 1 X PBS. DNAs were extracted from the samples by direct DNA extraction method using lysis buffer (0.5% EDTA, 1% Triton X-100). Identification of 7 putative pathogens was performed by PCR based on 16S rDNA. The target species were as follows: Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Bacteroides forsythus, Actinobacillus actinomycetemcomitans, and Treponema denticola. Our data revealed that the prevalence of P.endodontalis was found in 88.6% (39 / 54), P.gingivalis 52.3% (23 / 44), P.nigrescens 18.2%(8 / 44), P.intermedia 15.9% (7 / 44), B.forsythus 18.2% (8 / 44), A.actinomycetemcomitans 2.3% (1 / 44), T.denticola 25% (11 / 44) of the samples. The high prevalence of P. endodontalis and P.gingivalis suggests that they may play an important role in the etiology of endodontic infections.

초등학교 과학 수업에서 팀 게임 토너먼트(TGT) 협동학습의 효과

고한중,양수경,한재영,노태희 한국초등과학교육학회 2003 초등과학교육 Vol.22 No.3

The purpose of this study was to develop a way of using Teams Games Tournaments that fits in elementary school science instruction, and to find out its effects on student's learning. Three classes (103 sixth graders) were divided into three groups; a traditional learning group, a cooperative learning group, and a teams games tournaments cooperative learning group. Students were taught about 'several kinds of gas' for nine class periods. The instructional effects upon student's achievement, science learning motivation and self-esteem toward science instruction were examined. The result of this study indicated that there was a significant interaction effect between the treatment and achievement level in the achievement test scores. The achievement test scores of the low level students were significantly higher in the teams games tournaments cooperative learning group than those in the traditional learning groups.

심첨부 비후 심근증에서 심근 내 미세 관상동맥의 혈류 예비력 평가 : 경흉부 도플러 심초음파를 이용한 연구 Study Using Transthoracic Doppler Echocardiography

윤호중,박철수,신재원,임상현,조은주,정해억,전희경,오용석,정욱성,김재형,최규보,홍순조 대한순환기학회 2004 Korean Circulation Journal Vol.34 No.3

알루미늄 연속주조 용탕의 탈 가스 일체화 장치 개발

이용중,김태원,김기대,류재엽,이형우 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-

It is necessary for managing a perfect process for degasing aluminum molten metal according to the increase of a grade of aluminum and its alloy products. There are some methods that have been used to manage a degasing process in recent years, such as an injection method that uses aluminum molten metal powder and chemicals supplier and input method that supplies argon and nitrogen, or chlorine gas by using a gas blow-tube. However, these methods show some problems, and it shows that it is a difficult process to handle, pollution due to the producing a lot of toxic gases like chlorine and fluoride gas, irregular effects, and lowering work efficiency due to the excessive processing time. The problems that are the most fatal are the producing a lot of sludge due to the reaction of aluminum molten metal with chemicals, loss of metals, and decreasing the life of refractory materials. In order to solve these problems, this paper develops a technology that is related to aluminum continuous casting molten metal and monolithic degasing apparatus. A degasing apparatus developed in this study improved the existing methods and prevented environmental pollution with smokeless, odorless, and harmlessness by using a new method that applies argon and nitrogen gas in which the methods used in the West and Japan are eliminated. The developed method can significantly reduce product faults that are caused by the production of gas and oxidation because it uses a preprocessed molten metal with chemicals. In addition, the amount of the produced sludge can also be reduced by 60~80% maximum compared with the existing methods. Then, it makes it possible to minimize the loss of metals. Moreover, the molten metal processing and settling time is also shortened by comparing it with the existing methods that are applied by using chemicals. In addition, it does much to improve the workers' health, safety and environment because there is no pollution. The improvement of productivity and prevention effects of disaster from the results of the development can be summarized as follows. It will contribute to the process rationalization because it does not have any unnecessary processes that the molten metal will be moved to an agitator by using a ladle and returned to process for degasing like the existing process due to the monolithic configuration. There are no floating impurities due to the oxidation caused by the contact with the air as same as the existing process. In addition, it can protect the blending of precipitation impurities. Because it has a monolithic configuration, it can avoid the use of additional energy to compensate the temperature decreasing about 60? that is caused by the moving of molten metal. It is not necessary to invest an extra facilities in order to discharge the gas generated from a degasing process by using an agitator. The working environment can be improved by the hospitable air in the factory because the molten metal is almost not exposed in the interior of the area.

혼합입경을 가진 규조토 하상에서의 한계소류력에 관한 실험적 연구

김재중 동아대학교 공과대학 부설 한국자원개발연구소 1988 硏究報告 Vol.12 No.1

Sedimentation problems have been studied by many scientists and engineers. In general, the critical tractive force of mixed bed can be decided on Shields diagram in case that the representative diameter of bed materials can be determined. The purpose of this study is analyzing the results obtained by using the representative diameter(d_(R)), and comparing them to those obtained by using the conventional methods such as the median diameter(d_(50)) and the characteristics of the Diatomaceous soil. Experiments are performed for the rectangular two-dimensional slope changeable open channel with 12m long, 0.5m wide and the depth of 0.5m.

명지·녹산해역에서의 설계파 추정에 관한 연구

김재중,김인철,박정철 東亞大學校 海洋資源硏究所 1990 硏究論文集 Vol.3 No.1

Wave transformation in the shallow water region is a very important in the coastal process and is affected by wave refraction, diffraction and reflection. Berkhoff(1972) derived mild slope equation considering the coupled procedure of refraction and diffraction effect. This mild slope equation is elliptic partial differential equation type. Despite of elliptic nature of mild slope equation, shoreward marching finite difference scheme is employed under the assumption of negligibility of reflected wave field. Numerical experiments of combined refraction-diffraction at the submerged elliptic shoal of Berkhoff et al(1982) was performed. The experimental results was compared with this model. The model applied in the Myungji-Nocksan region and the wave height at the designed seawall boundary is calculated.

심음간격의 분석을 이용한 부정맥 및 자율신경계통의 변화에 대한 연구

임재중 인제대학교 1993 仁濟論叢 Vol.9 No.1

Both left ventricular function and central nervous function assessments require the electrocardiogram which requires electrodes. If RSA can be obtained using heart sounds and a relationship can be established it would be a powerful diagnostic tool. The data were obtained from ten healthy males(age span20-35 years old). The subjects were seated in a chair against a wall where a red light was positioned in the subject's field of vision. Each subjects were asked to perform controlled breathing for 20 trials : 5 trials at each of four breathing rates (6,9,12, and 15 breaths per minute). During each trial three signnals were acquired from all subjects, i.e., the ECG, the heart valve sounds at the trachea, and a pneumogram. The TMS32010 high speed digital signal processing chip, TMS9900 controller, and 4K of on board memory were used to collect and process the data. Once a trial was complete and all of the data was in memory, all 200 files were processed and saved the various heart valve sound time interval parameters TBB, T11, T22, T12 for further statistical analysis(regression analysis and t-statistics). The R2 values for TBB, T11, and T22 are high as expected. Also, the estimates for β1 are close to 1 as expected. The results strongly suggest the existance of heart sound RSA. Further, they show a high correlation between the mean estimated heart periods from T11 and T22 are the mean estimated heart period from TBB. The peak to peak interval of the experimental heart sounds is close to the clinically useful LVET. This system would be capable of obtaining the individuals heart and respiratory rates, the condition of his central nervous system and the condition of his heart, however, a better recording system must be developed to insure reliable operation.

중학교 과학교육을 위한 멀티미디어 학습자료 개발 연구 : 화학분야를 중심으로 with a focus on chemistry

김일중,김재현 공주대학교 사범대학 과학교육연구소 1998 과학교육연구 Vol.29 No.1

인터넷을 이용하여 학습할 수 있는 자료로서 인터넷 홈페이지 제작 언어인 HTML과 JAVA로 제작되었다. 현행 중학교 3학년 과학 Ⅲ 단원인 "물질의 반응"을 내용으로 학습자가 학습내용의 이해를 증진토록 하였다. 본 연구는 학습자가 컴퓨터로 인터넷에 접속하여 학습자가 개별 학습을 가능케 하였고, 내용을 그래픽과 애니메이션으로 표현하여 학습자가 과학 학습에 대한 흥미를 갖도록 하였다. This research is produced as a homepage of learning materials with which students can study through the internet, and is made with the internet languages, HTML and JAVA. It contains "Reactions of Matter," which is the third chapter of the current middle school science textbook for third graders, so that the learners can adapt to the information-oriented society. The keynote of this research is that the students can study individually through logging into the internet on their own computers; the program is made using graphics and animation in order to develop the learners' interest in science.