초음파 시험에 의한 자기유체의 탄성율 산정

김종희,김건우,김철기,이승구,구만회,Kim, Jong-Hee,Kim, Kun-Woo,Kim, Cheol-Gi,Lee, Seung-Goo,Koo, Man-Hoi 한국재료학회 2012 한국재료학회지 Vol.22 No.3

Magnetic nanoparticles for ferromagnetic fluids and magnetorheological fluids were prepared by chemical coprecipitation and mechanical milling, respectively. The surface-treated particles were dispersed at various weight ratios into a medium of polyethylene glycol. In order to evaluate the elastic modulus of the fluids, ultrasonic pulse velocities were measured with an ultrasonic test using transducers of 5MHz and 2.25MHz. The ultrasonic signals were only available with a transducer of 2.25 MHz at fluid concentrations of 5 mg/ml and lower. In the case of applying transducers over 2.25 MHz and concentrations over 5 mg/ml to the fluids, it was impossible to observe effective ultrasonic signals due to an excessive scattering of the pulses by the dispersed particles. Elastic moduli of the magnetorheological fluids were 5.44 GPa and 6.13 GPa with concentrations of 25 mg/ml and 50 mg/ml, respectively; these values were higher by 40% than the values of 4.04 GPa and 4.28 GPa of ferromagnetic fluids at the same concentrations. As for the effect of an external magnetic field on these dilute fluids, the ultrasonic signals were positioned in a very similar way, which was probably due to insufficient arrangement of the particles even though the reflection energy of the ultrasonic waves apparently increased.

회전 방지용 Post Screw 시스템의 임플랜트 지대나사풀림 방지효과에 관한 연구

김종희,임주환,조인호,이준석,Kim Jong-Hui,Lim Ju-Hwan,Cho In-Ho,Lee Joon-Seok 대한치과보철학회 2005 대한치과보철학회지 Vol.43 No.5

Statement of problem: The most commonly reported problem associated with dental implant restoration is the loosening of the screws. Purpose: This study compared the efficacy of an implant system incorporating an anti-rotational locking sleeve(Anti-Rotating Inner Post Screw System(ARIPS-system)) with other, traditional implant systems as a means of minimizing vibration loosening. Materials and methods: Three implant systems were examined; the conventional external hex type, the ARIPS-system, and the internal taper type implant system 30 specimens(10 samples per group)were fabricated and each abutment screw was secured to the implant future with 32Ncm of torque force and loosening torque was measured using a Torque Gauge. The procedure was repeated 3 times, recording initial loosening torque each time. The re-tightened abutment screw was subjected to a cyclic load having a maximum forte of 200N and minimum of 20N at 2Hz over a period of 12,600 cycles. after which the loosening torque was measured. Measured values were calaulated for statistical analysis. Analysis of measured value was performed by 3 methods: (i) as a percentage average of the initial 3 loosening-torque values(initial loosening value) to the tightening torque of 32Ncm, (ii) as a percentage of the loosening torque value after a load of 200N(experimental value) to the initial loosening value, and (iii) as a percentage of the experimental value to the 32Ncm of tightening torque. The analyses shows the amount of initial loosening at the screw, loosening by repetitive load and the the final loosening value. Results: The results of this study were as follows (1) Percentage of initial loosening value to tightening-torque was increased in order of external hex, ARIPS-system and internal taper and all values between each groups showed statistical significance (p<0.05). (2) Percentage of experimental value to initial loosening value was increased in order of external hex, ARIPS-system and internal taper. Value of internal taper showed significant difference with those of external hex and ARIPS-system (p<0.05). (3) Percentage of experimental value to tightening torque was increased in order of external hex, ARIPS-system and internal taper and all values between each groups showed statistical significance (p<0.05). Conclusion: The results of the analysis of the final loosening level value, which are closely correlated to clinical use, show that the ARIPS-system can be a useful means of minimizing abutment screw loosening when compared to the external hex type system. Although further clinical studies need to be made, the ARIPS-system should be considered to maximize the long-term success of the implant prosthesis.

연료극 지지체식 평관형 고체산화물 연료전지 특성 연구

김종희,송락현,Kim Jong-Hee,Song Rak-Hyun 한국전기화학회 2004 한국전기화학회지 Vol.7 No.2

Anode-supported flat tubular solid oxide fuel cell (SOFC) was investigated to increase the cell power density. The anode-supported flat tube was fabricated by extrusion process. The porosity and pore size of Ni/YSZ ($8mol\%$ yttria-stabilized zirconia) cermet anode were $50.6\%\;and\;0.23{\mu}m$, respectively. The Ni particles in the anode were distributed uniformly and connected well to each other particles in the cermet anode. YSZ electrolyte layer and multilayered cathode composed of $LSM(La_{0.85}Sr_{0.15})_{0.9}MnO_3)/YSZ$ composite, LSM, and $LSCF(La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.7}O_3)$ were coated onto the anode substrate by slurry dip coating, subsequently. The anode-supported flat tubular cell showed a performance of $300mW/cm^2 (0.6V,\; 500 mA/cm^2)\;at\;500^{\circ}C$. The electrochemical characteristics of the flat tubular cell were examined by ac impedance method and the humidified fuel enhanced the cell performance. Areal specific resistance of the LSM-coated SUS430 by slurry dipping process as metallic interconnect was $148m{\Omega}cm^2\;at\;750^{\circ}C$ and then decreased to $148m{\Omega}cm^2$ after 450hr. On the other hand, the LSM-coated Fecralloy by slurry dipping process showed a high area specific resistance. 연료극 지지체 평관형 고체산화물 연료전지(SOFC)의 셀 전력밀도를 증가시키기 위하여 압출법에 의하여 제조하고 그 특성을 연구하였다. 연료극 지지체로써 Ni/YSZ($8mol\%$ yttria stabilized zirconia) cermet는 기공율 $50.6\%,\;0.23{\mu}m$의 기공크기를 나타내었다. 지지체에서의 Ni의 분포는 균일하였으며 전자전도 경로로써의 Ni의 연결성은 양호하였다. 지지체에 YSZ전해질과 복합 공기극층인 $LSM((La_{0.85}Sr_{0.15})_{0.9}MnO_3)/YSZ$ 복합층, LSM, LSCF $(La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3)$층이 슬러리 디핑법에 의하여 코팅 및 소결된 연료극 지지체식 평관형 고체산화물 연료전지 단위전지의 성능은 $800^{\circ}C$에서 $300mW/cm^2(0.6V,\;500mA/cm^2)$의 성능을 나타내었다. 임피던스 분석에 의하여 평관형 셀의 전기화학적 분극저항을 평가하고 연료측의 가습에 따라 분극저항이 감소되어 성능이 향상됨을 알 수 있었다 슬러리 디핑법으로 LSM이 코팅된 SUS430 금속연결재를 $Ar+10\%\;H_2$에서 소결하였으며, $750^{\circ}C$에서 면저항의 측정할 결과, 초기에는 $148m{\Omega}cm^2$를 나타내었으며, 450시간 경과 후에 $43m{\Omega}cm^2$의 낮은 면저항을 유지하였다. 반면에 동일한 조건으로 LSM이 코팅된 Fecralloy는 높은 면저항을 나타내었다.

교육공무원법에 있어서의 사서교사의 자격기준의 문제점

김종희,Kim, Jong-Hui 한국도서관협회 1964 圖協月報 Vol.5 No.9

국내 정보산업 육성정책

김종희,Kim, Jong-Hui 한국전자정보통신산업진흥회 1987 電子振興 Vol.7 No.3

청소년기 척추 측만곡증 및 학교 집단검진

김종희,Kim, Jong-Hui 한국학교보건협회 1998 학교보건 Vol.21 No.-

국내 정보산업의 육성 방향

김종희,Kim, Jong-Hui 한국전자정보통신산업진흥회 1986 電子振興 Vol.6 No.3

직접 교수 모형에 기반한 체육과 ICT활용 교수 학습 과정안 개발 및 적용

김종희,이재무,Kim, Jong-Hee,Lee, Jae-Mu 한국정보교육학회 2005 정보교육학회논문지 Vol.9 No.3

The goal of this research is to prove the efficiency of direct instruction by developing and applying an ICT teaching and learning course for physical education based on a direct instruction model. The curriculum for physical education requires the instructors example and feedback, and sometimes classes may be difficult to conduct due to reasons such as weather conditions. Also, in actual learning, the application of a learning model is inadequate. In these cases, using an ICT teaching and learning course, experts can show examples instead. The learners are provided with individual and suitable feedback and can make it practical for them by slowing down motions, sectional motion learning, and repetitive learning. It can also enhance the sharing of the instructors teaching and learning methods. Therefore, this research recomposed the commonly used direct teaching and learning methods in physical education in order to make it suitable for ICT utilized lessons. It was recomposed in a procedural model and each level was explicated, and in order to materialize this, an ICT teaching and learning course was developed. This was then applied to a Fifth grade class, and its learning effects were analyzed.

자색고구마 스펀지케이크의 저장기간 변화에 따른 품질 특성

김종희,이근종,Kim, Jong-Hee,Lee, Kun Jong 한국식품영양학회 2014 韓國食品營養學會誌 Vol.27 No.4

The quality and characteristics of purple sweet potato sponge cake were studied with the addition of different proportions of purple sweet potato powder depending on storage period The pHs, heights, and weights of doughs were in the ranges of 6.3~6.5, 4.8~4.4 cm and 397~418 g, respectively. The sponge cake groups with the addition of different proportions of purple sweet potato powder showed significantly different characteristics in hardness, adhesiveness, cohesiveness, gumminess, and chewiness, according to texture profile analysis. The difference in colors of sponge cakes with addition with purple sweet potato revealed that L-value and b-value were significantly reduced but a-value especially increased according to the density. Using scanning electron microscopy (SEM), it was confirmed that the stoma size of purple sweet potato sponge cake become smaller and the stoma wall became thicker in proportion to the contents of purple sweet potato powder, which could result in an increased level of water content after a long period pf storage. According with the observations, water content remarkably increased after 4~6 days of storage and the ability to keep water content seemed to contribute to extention the shef-life of sponge cakes. In sensory evaluation, sponge cakes with high contents of purple sweet potato were preferred and cakes with the addition of 25% and 30% purple sweet potato powder was most preferred. It was expected that the shelf-life of purple sweet potato sponge cake was 4 days under the normal temperature.

토마토 MABC 육종에서 GBS(genotyping-by-sequencing)에 의한 RPG(recurrent parent genome) 회복률 분석

김종희,정유진,서훈교,김명권,노일섭,강권규,Kim, Jong Hee,Jung, Yu Jin,Seo, Hoon Kyo,Kim, Myong-Kwon,Nou, Ill-Sup,Kang, Kwon Kyoo The Korean Society of Plant Biotechnology 2019 식물생명공학회지 Vol.46 No.3

Marker-assisted backcrossing (MABC)은 marker-assisted selection (MAS)와 함께 다양한 작물에서 여교배 초기세대에서 반복친 게놈의 회복률이 높은 개체선발을 위한 분자육종 기술로 매우 유용하게 사용하고 있다. 본 연구에서는 토마토 MABC 육종 프로그램의 일환으로 저장성이 강한 rin유전자를 주)토마토연구소에서 육성한 핑크계 엘리트 토마토계통에 도입하고자 수행하였다. foreground 선발은 RIN SCAR 분자 마커를 이용하여 100개 $BC_1F_1$ 식물체에서 Rr 유전자형 가진 42개체를 선발하였다. 그리고 이를 이용하여 GBS 분석을 이용하여 background 선발을 하였다. 총 3,086개 SNP를 대상으로 반복친 HK13-1151과 게놈 회복률을 조사한 결과, 56.7%에서 84.5%를 보여 평균 70.5%로 나타났다. 이 중 87.2%을 보인 $BC_1F_1$개체를 이용하여 192개 $BC_2F_1$ 식물체를 육성하여 foreground 선발을 하였다. 선발된 102개 중 88개 식물체를 이용하여 GBS 분석을 수행한 결과 4,868개의 다형 SNP 마커를 얻었으며, 이를 이용하여 RPG 회복률을 조사하였다. $BC_2F_1$ 식물체들에서 HK13-1151 반복친 게놈과 87.8%에서 97.8% 유사하였다. 본 연구에서 $BC_2F_1$ 식물 중 RPG 회복률이 97.8%인 5-1 개체는 반복친인 HK13-1151과 과일특성에서 매우 유사하였다. 따라서 선발된 5-1 개체는 $BC_2F_2$ 세대를 육성하여 계통화 하고자 한다. 본 연구를 통해 MABC는 전통 여교배 육종에 비해 육종연한을 획기적으로 줄일 수 있으며, 원하는 육종모델을 완수할 수 있는 첨단육종 기술로 평가 할 수 있다. Marker-assisted backcrossing (MABC) is useful for selecting an offspring with a highly recovered genetic background for a recurrent parent at early generation to various crops. Moreover, marker-assisted backcrossing (MABC) along with marker-assisted selection (MAS) contributes immensely to overcome the main limitation of the conventional breeding and it accelerates recurrent parent genome (RPG) recovery. In this study, we were employed to incorporate rin gene(s) from the donor parent T13-1084, into the genetic background of HK13-1151, a popular high-yielding tomato elite inbred line that is a pink color fruit, in order to develop a rin HK13-1084 improved line. The recurrent parent genome recovery was analyzed in early generations of backcrossing using SNP markers obtained from genotyping-by-sequencing analysis. From the $BC_1F_1$ and $BC_2F_1$ plants, 3,086 and 4868 polymorphic SNP markers were obtained via GBS analysis, respectively. These markers were present in all twelve chromosomes. The background analysis revealed that the extent of RPG recovery ranged from 56.7% to 84.5% and from 87.8% to 97.8% in $BC_1F_1$ and $BC_2F_1$ generations, respectively. In this study, No 5-1 with 97.8% RPG recovery rate among $BC_2F_1$ plants was similar to HK13-1151 strain in the fruit shape. Therefore, the selected plants were fixed in $BC_2F_2$ generation through selfing. MAS allowed identification of the plants that are more similar to the recurrent parent for the loci evaluated in the backcross generations. MABC can greatly reduce breeding time as compared to the conventional backcross breeding. For instance, MABC approach greatly shortened breeding time in tomato.