알루미늄 샌드위치 판넬의 전자파 차폐효과

한길영,김진석,안동규 朝鮮大學校 機械技術硏究所 2006 機械技術硏究 Vol.9 No.1

The objective of this research is to investigate the electromagnetic interference(EMl) shielding characteristics of aluminium sandwich panel. We fabricated aluminium sandwich panel with core material Ni-Cu fabrics. The measurements of shielding effectiveness(SE) were carried out frequency range 300MHz -1 GHz for commercial purposes such as electric or telecommunication devices. The return loss and loss due to absorption were also measured as a function of frequency in the microwave(300MHz-1GHz) region. It is observed that the SE of the composites is the frequency dependent, increases with the increases in filler loading. The Ni-Cu fabrics core material showed higher SE compared to that of AI. The aluminium sandwich panel was shown to exhibit up to 40dB of SE.The results indicate that the composite having higher filler loading can be used for the purpose of EMI shielding as well as for some microwave applications.

시멘트 제조사 및 W/C 변화에 따른 콘크리트의 초기 강도발현 특성

金光華,裵正烈,김규도,이승훈,한천구 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)

This study is to investigate the influence of cement manufacturing company and W/C on the properties of fresh concrete, strength of hardened concrete and rebound value of P type Schmidt hammer. According to the result, setting time of concrete is shortened with and increase of W/C, and when cement made in A and B corporation is used in concrete, the final setting time is measured at about 10 hours and 13 hours. Compressive strength increases with elapse of time and decrease of W/C, and concrete using cement made in A corporation shows higher compressive strength and rebound value until 24 hours, but from 3rd day, the contrary tendency is shown. As for the properties of early strength, the strength develop fast with decrease of W/C, and the time when compressive strength of 5MPa is gained and the form can be removed, is about 15, 18, 21 hours and 20, 22, 27 hours at the W/C 40, 45, 50% in concrete using cement made in A and B Co. respectively. The correlativity between compressive strength and the rebound value, which a coefficient of correlation is over 0.97, is very favorable. Therefore this method is effective to estimate the strength of removing the form.

차량관제시스템을 위한 Inverted DGPS 시스템

한승재,홍진석,지규인 건국대학교 1997 學術誌 Vol.41 No.2

Vehicle Monitoring System which can efficiently control and manage the resources like vehicles, cargos and services is required in many transportation related areas like ITS /IVHS. GPS or DGPS is widely used in determining the vehicle location in service. DGPS can glove more accurate position than GPS, but it needs an additional wireless communication link for DGPS correction reception from the DGPS reference station. But, in some applications lire tall or truck monitoring system, the user doesn't need to know the his accurate position. The DGPS correction can be performed in the monitoring station based on the informations from the GPS receiver in the user vehicle and then the monitor station can locate vehicle position accurately like conventional DGPS. For this case an additional communication link for DGPS RTCM is not necessary. This method is called inverted DGPS. In this paper we develop an IDGPS system algorithm and implement it using wireless data modem network and digital map. Test results show its effectiveness. Key Words : GPS, DGPS, Inverted DGPS, vehicle Monitoring System, RTCM

쌀의 수침시간 및 증자시간에 따른 가래떡이 품질 특성

유진현,한규홍 한국조리과학회 2004 한국식품조리과학회지 Vol.20 No.6

The effects of soaking and steaming time on the quality characteristics of Korean rice cake (karedduk) were investigated. As the soaking time increased, the water-binding capacity and rice floor solid content also increased. After 8 to 10 hr soaking, 75.2 to 76.8% of particles were smaller than 40 gm, and 23.2 to 24.8% within the range of 40 to 100 ㎛. Therefore, an extended soaking time reduced the particle size. Texture is an important characteristic used to differentiate karedduk varieties, and is considered by the consumer as a determinant of the overall quality and preference. The hardness, cohesiveness, gumminess and chewiness of the karedduk structure decreased with increasing steaming time, but the springiness was highest after a 40 min steaming time. The overall texture properties were also more acceptable with 8 and 10 hrs soaking times. The L value of the karedduk decreased with increasing steaming time, but the b value increased. Also, the results of the sensory evaluation showed that an 8 hr soaking time and 40 min steaming time produced more acceptable karedduk in terms of whiteness, texture, springiness, chewiness and overall acceptability.

Parthenogenetic Activity of Porcine Sperm Factor to In Vìtro Matured tured Porcine Oocyte

Park, Chun_Gyu,Jin-Ki Parκ,Sung-Woo Kim,Ju-Young Lee,Joo-hee Han,Seung-Eun Lee,Kyung-Nye Baek,Won-Chung Chang 한국동물생명공학회(구 한국동물번식학회) 2004 Reproductive & Developmental Biology(Supplement) Vol.28 No.2s

교육용 소프트웨어 개발에 적합한 하이퍼미디어 시스템에 관한 연구

박성한,정혜윤,한민규,심진석 한양대학교 공학기술연구소 1993 공학기술논문집 Vol.2 No.1

This paper presents a back-end system of hypermedia authoring system for courseware development. For the design, repersentative hypertext reference models, the Dexter model and the HAM(Hypertext Abstract Machine) which belongs to Campbell & Goodman model were analyzed. Based on those models, data objects, attributes, and operations of back-end system were designed and implemented. Because the application area of this system is on computer based education, the path mechanism is enforced for the various educational strategies. In order to reduce the user disorientation and cognitive overheads in navigating hypernetwork, filtering, backtracking and history mechanism were implemented.

트리에탄올아민의 혼입률 변화에 따른 콘크리트의 초기 강도발현 특성

황인성,金光華,김규동,이승훈,한천구 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)

In this study, the influence of TEA on early strength development of concrete is discussed in order to reduce a construction period in RC structure by early removal of forms. According to the results, as for the properties of fresh concrete, fluidity of concrete shows no difference, and air content increases with an increase of the mixing ratio of TEA. Setting time is shortened upto mixing ratio of 0.025%, but is retarded above the mixing ratio of 0.025%. The time when compressive strength gains 5MPa is fast in about 2 hours in the case of the mixing ratio of 0.05%, but it is retarded above the mixing ratio of 0.05%. The relativity between compressive strength and the rebound value of P-type Schmidt hammer is also favorable at early age, and compressive strength of 5MPa, which the side forms can be removed, is estimated at the rebound value of 23.

경사진 입구를 갖는 급확대관내의 난류유동과 열전달특성에 관한 실험적 연구

권기린,한진규 濟州大學校 工科大學 産業技術硏究所 1994 産業技術硏究報告 Vol.5 No.-

Experiments were carried out for the turbulent flow and heat transfer downstream of an 10^(2) -inclined concentric expansion in a circular pipe with a constant wall heat flux. The uniform heat flux condition was imposed to the downstream of an inclined expansion by using an electrically heated pipe and the folw upstream of the expansion was unheated and fully developed. Runs were made with small diameter to large diameter ratio of 0.33 and over the Reynolds numbers range of 60,000, 90.000 and 120,000 (based on upstream diameter). Experiments were tested with air as working fluid. The results ovtained are summarized as follows; 1) Fully development region showed from x/d=22 to downstream in an 10^(2) - inclined concentric expansion turbulent flow through the test tube. 2) Friction factors of the test tube showed a maximum value at x/d=15. 3) For all Reynolds number, the wall temperature showed a curve of parabolic variation at 16<x/d<48, and the bulk temperature showed a linear distribution of increse at 9<x/d<48. 4) The location of the maximum Nu/NuDB showed at the point of 16 step-heights for Re= 60,000, 90,000 and 120,000 of an 10^(2) - inclined concentric expansion.

교육대학생의 학습량 조사 분석 연구 : 과제물의 양과 해결을 중심으로

고대혁,허 숙,한안진,김규환 仁川敎育大學校 1994 論文集 Vol.28 No.2

University education is not enough with only lectures in order to achieve its educational goals. University is, by definition, a place where inividual academic researches and studies of professors and students are to take place. For this purpose, university students are required to do various kinds of home work, individual study, and report writing. This study tries to investigate the types and amount of individual learning tasks which is provided to the students of Inchon National Teachers University. There are various kinds of individual learning tasks : reading books, finding material, observation and experimentation, skill practice, and report writing. As the results of the study, we can find that : (1) Students are required to take more or less than 10 courses in a semester and every course require 2 or 3 reports. (2) Many students feel that the amount of individual tasks are too heavy to solve within the given time. Especially, the most heavy amount of tasks are given during the third year of university curriculum. (3) Most of the students think that individual study tasks are necessary for university education. But they hope the tasks should be inquiry-oriented rather than memory or mechanical work-oriented. (4) Students want to have a space like Curriculum Material Preparation Area(CMPA) in order to make individual learning tasks.

순차적 크리깅기법을 이용한 미소혼합기의 최적화

박재용,유진식,황승민,임민규,오영규,김용대,한석영,맹주성 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-

An active micro-mixer, which is composed of an oscillating micro-stirrer in the micro-channel to provide effective mixing was optimized. The effects of molecular diffusion and disturbance by the stirrer were considered with regard to two types of mixer models: the simple straight micro-channel and micro-channel with an oscillating stirrer. Two types of mixer models were studied by analyzing mixing behaviors such as their interaction after the stirrer. The mixing was calculated by Lattice Boltzmann methods using the D2Q9 model. In this study, the time-averaged mixing index formula was used to estimate the mixing performance of time-dependent flow. The mixing indices of the two models were compared. From the results, it was found that the mixer with an oscillating stirrer was much more enhanced' and stabilized. Therefore, an approximate optimization of an active micro-mixer with an oscillating stirrer was performed using Kriging method with OLHD (Optimal Latin Hypercube Design) in order to determine the optimal design variables. The design parameters were established as the frequency, the length and the angle of the stirrer. The optimal values were obtained as 1.5754, 0.803D and ±45°, respectively. It was found that the mixing index of the optimal design increased by 83.36% compared with that of the original design.