이종금속간 용접 계면에서의 미혼합역 형성

이창희,Lee, Chang-Hee 대한용접접합학회 2007 대한용접·접합학회지 Vol.25 No.4

Mie 산란 방법과 엔트로피 해석 방법을 이용한 혼합연료비에 따른 분무 균질도 특성에 관한 연구

이창희,이기형,이창식,배재일,Lee, Chang-Hee,Lee, Ki-Hyung,Lee, Chang-Sik,Bae, Jae-Il 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.1

In this study, his technique was applied to a GDI spray in order to investigate the mixture distribution. In addition, the homogeneity degree and diffusion effect according to ambient temperature in the high pressure chamber were analyzed by using an entropy analysis method. From this experiment, we could find that entropy analysis is very effective method for the analysis of mixture formation, and the entropy values increase with the progress of uniformity in diffusion Process. we tried to provide the fundamental data for parameter which effects on the spray macroscopic characteristics with mixture ratio of diesel and gasoline. In addition, the mixture formation was analyzed by using entropy analysis. The entropy analysis is based on the concept of statistical entropy, and it identifies the degree of homogeneity in the fuel concentration. From the entropy analysis results we could find that the direct diffusion phenomena is a dominant factor in the formation of a homogeneous mixture at downstream of GDI spray especially in vaporizing conditions. As to increasing ambient temperature and increasing gasoline rate, the entropy intensity using the statistic thermodynamics method is increased because evaporation rate is higher gasoline than diesel.

포스타 : 태아 초음파 검사상 장관의 이상과 출생후 소견과의 연관성

이창희,김영한,조재성,박용원 대한산부인과학회 2001 대한산부인과학회 학술대회 Vol.87 No.-

음향주파수 분석에 의한 엔드밀의 마모상태 추정에 관한 연구

이창희,조택동 대한기계학회 2003 大韓機械學會論文集A Vol.27 No.8

직분식 가솔린 인젝터의 흡입 행정 분사시의 연료 거동 및 혼합기 분포 특성에 관한 연구

이창희,이기형,배재일,백승국,Lee, Chang-Hui,Lee, Gi-Hyeong,Bae, Jae-Il,Baek, Seung-Guk 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.8

Recently GDI(Gasoline Direct Injection) engine is spot-lighted to achieve higher thermal efficiency under partial loads and better performance at full loads. To realize this system, it is essential to make both stratified combustion and homogeneous combustion. Spray pattern must be optimized according to injection timing because ambient pressure in combustion chamber is varied with crank angle. In this experimental study, two types of visualization system such as laser scattering method and schlieren method were developed to clarity the spray behavior during on intake stroke. As the ambient pressure increases, thepenetration length and spray angle show a tendancy to decrease due to rising resistance caused by the drag force of the ambient air. Distribution of injected fuel on intake stroke has a significant effect on homogeneous mixture in the cylinder. These results provide the information on macroscopic wall-wet growth in the cylinder and design factors for developing GDI injector.

Changes in Phenolic Compounds and Abscisic Acids in Liriope spicata Seeds accroding to Cold Stratification and Seed Harvesting Date and Their Relationships to Germination

이창희,김선기,Jiny Lee 한국원예학회 2006 Horticulture, Environment, and Biotechnology Vol.47 No.1

This study was conducted to investigate the changes in total phenolic compounds and abscisic acid (ABA) according to cold stratification and seed harvesting date, and to examine the relationship between germination and the two probable inhibitors in Liriope spicata (creeping lily-turf) seeds. Germination percentage increased in a stratification duration-dependent manner and further stratification beyond 30 days did not show significant difference. Although total phenolic compounds and ABA contents of stratified seeds ranged from 30 to 60 days after cold stratification were slightly reduced, those of the seeds ranged from 0 to 30 days after cold stratification markedly decreased in a duration-dependent manner. Especially, total phenolic compounds and ABA within the seeds greatly decreased during the first 30 days of cold stratification. Depulped L. spicata seeds collected on October 12 did not germinate at all until 40 days after sowing, while those on following harvesting dates ranged from October 22 to December 21 showed various germination percentages ranged from 11.5 to 93.2%. Maximum germination percentage (93%) was obtained from seeds harvested from November 22 and December 1. The lowest content of phenolic compounds within seeds were found on November 22, following December 1, December 11, November 12, sequentially. The increase and decrease pattern of ABA during seed development was very similar to those of phenolic compounds within seeds. In conclusion, enhancing germination by depulping and cold stratification could be attributed to the removal of phenolic compounds and ABA within the pulps and the seeds of L. spicata. In addition, reduction of phenolic compounds contents and ABA within seeds during seed development seemed to be positively correlated with their germination percentage according to seed harvesting dates.

초록보고 : 증례보고 ; 산과학 : 합병증 ; 제왕절개 수술시 발견된 비파열성 좌측 난관임신 1예

이창희,서수형,조태승,신영우,배동한 대한산부인과학회 1990 대한산부인과학회 학술대회 Vol.66 No.-

The Effects of Calcium Nutrition on the Activities of Lactate Dehydrogenase, Alcohol Dehydrogenase and Other Enzymes in Melon (Cucumis melo L.) Seedlings Subjected to Flooding

이창희,박만,강상재 한국토양비료학회 2016 한국토양비료학회지 Vol.50 No.4

With transient flooding followed by poor or slow drainage plant roots may become reduction conditions because the root zone was fully filled with water. This study was examined the effects of calcium treatment in the early growth stage on biochemical changes in leaves and roots of melon (Cucumis melo L.) seedlings kept under flooding condition for 72 h. The activities of lactate dehydrogenase more gradually enhanced in the roots than those of leaves of melon seedlings treated with calcium. The activities of alcohol dehydrogenase associated with alcohol fermentation under low oxygen conditions continuously increased in the leaves and roots of seedlings untreated with calcium under flooding at least 72 h but those was constant within at least 12 h in treated with calcium. These results showed that calcium supplying in the early growth stage mitigated alcohol fermentation of melon seedlings kept under flooding condition for 72 h. Activities of nitrate reductase and acid phosphatase in the leaves and roots of seedlings in treated with calcium somewhat higher than those of non-treated with calcium. The activities of sucrose phosphate synthase and fructose-1,6-bisphosphatase of leaves of seedlings in treated with calcium more higher than those of non-treated with calcium. These results indicated that calcium nutrition mitigate the reduction of activities of some enzymes of melon seedling kept under flooding condition for 72 h.

Solid Matrix Priming with Hydrogels on Heteropappus arenarius Seeds

이창희 한국원예학회 2013 원예과학기술지 Vol.31 No.6

This study was initiated to evaluate hydrophilic polymers (hydrogels) as a new solid matrix medium for seed-priming of Heteropappus arenarius Kitam. Solid matrix priming (SMP)-media were prepared with the combination of Na- and K-based hydrogels and hydrogels with three different dry levels (DC; 70%,80%, and 90%). Priming was performed in the dark at 15 or 20°C for 24 hours, and all primed seeds were incubated at 20°C in the dark for the germination test. Non-primed seeds and seeds primed with distilled water (DW) were also included. To reach the germination rate of 50% (T50), it took 4.0 days for non-primed seeds, and 3.6 and 3.9 days for DW-primed seeds at 15 and 20°C, respectively. Na-based hydrogel-primed seeds with 70% DC (Na 70%) showed the fastest germination, which respectively took and 1.9 and 1.8days at 15 and 20°C to T50. K-based hydrogel-primed seeds with 70% DC showed the fastest germination among K-based hydrogels with various DC levels, but it took 0.6 days more to T50 compared to Na 70%. The hydration rate (HR) of DW-primed seeds was 37% lower than that of Na 70%-primed seeds at 15°C priming temperature, which indicates that Na 70% priming is the best solid matrix priming condition for promoting the germination of H. arenarius seeds.

FPGA를 이용한 CDMA 디지털 트랜시버의 구현

이창희,이영훈 한국컴퓨터정보학회 2002 韓國컴퓨터情報學會論文誌 Vol.7 No.4