• 한국정밀공학회지
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• 제22권1호
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• pp.137-142
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• 2005

Gas-Assisted Injection Molding(GAIM) is an innovative technology for producing plastic parts and has been received extensive attention in the plastic manufacturing industries. But, due to gas-polymer interacting during the gas injection phase, the process has significantly different characteristics from conventional injection molding and, therefore, the control of the process requires much technical knowledge in processing and materials. The experiment was performed about variations of gas-penetration length that is affected by filling imbalance resulting from the structure of runner. The Taguchi method was used for the design of experiment. The most effective factors for the gas-penetration length were the shot size and mold temperature. The most effective factors for the difference of the gas-penetration length were the melt temperature and shot size. This study also discussed the filling imbalance phenomenon in a unary branch runner type mold that has geometrically balanced runner.

• 한국지진공학회논문집
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• 제17권3호
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• pp.133-141
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• 2013

This paper presents the seismic evaluation and prediction of a damaged piloti-type Reinforced Concrete (RC) building before and after post-retrofitting under successive earthquakes. For considering realistic successive earthquakes, the past records measured at the same station were combined. In this study, the damaged RC building due to the first earthquake was retrofitted with a buckling-restrained brace (BRB) before the second earthquake occurred. Nonlinear Time History Analysis (NTHA) was performed under the scaled intensity of the successive ground motions. Based on the extensive structural response data obtained form from the NTHA, the fragility relationships between the ground shaking intensity and the probability of reaching a pre-determined limit state was were derived. In addition, The the fragility curves of the pre-damaged building without and with the BRBs were employed to evaluate the effect of the successive earthquakes and the post-retrofit effect. Through the seismic assessment subjected to the successive records, it was observed that the seismic performance of the pre-damaged building was significantly affected by the severity of the damage from the first earthquake damages and the hysteresis behavior of the retrofit element.

• Journal of Advanced Marine Engineering and Technology
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• 제11권3호
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• pp.31-44
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• 1987

Nowadays, the problems of energy and environmental pollution become serious day by day and the diesel engine, which has been proved to be superior to gasoline engine with respect to fuel consumption and ecological problems of exhaust gas, has been adopted widely for various purposes from the marine diesel engine and the dynamo engine to all kinds of engine on land. Therefore, extensive parametric studies on combustion of diesel engine should be done for its desing and improvement. To predict the behavior of diesel engien according to variable operating conditions by means of cycle simulation, the reasonable pattern of heat release rate has to be asumed. But it is necessary to know the actual variation of heat release rate in order to assume the reasonable pattern of heat release rate according to the actual operating conditions. In this paper, on a high speed small bore diesel engine with pre-combustion chamber, experimental investigations were carried out to determine the relationship between the heat release pattern and parameters such as engine load and speed. And also, the theoretical investigations about the performance variations of the above diesel engine according to the predicted pattern of heat release rate variation were performed. From the above observations, it may be said that the Fanboro indicator, which was used to get the cylinder pressure, can be used to estimate a reasonable pattern of heat release rate and it is confirmed that the pattern of heat release rate for the pre-combustion type engine is different from that of the direct injection type engine.

• 한국수소및신에너지학회논문집
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• 제8권2호
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• pp.79-90
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• 1997

Extensive work has been done on investigating the inner cell pressure characteristics of sealed type Ni-MH battery in which Zr-Ti-Mn-V-Ni alloy is used as anode. The inner cell pressure of this type Ni-MH battery much more increases with the charge/discharge cycling than that of the other type Ni-MH battery where commercialized $AB_5$ type alloy is used as anode. The increase of inner cell pressure in the sealed type Ni/MH battery using Zr-Ti-Mn-V-Ni alloy system is mainly due to the accumulation of oxygen gas during charge/discharge cycling. The accumulation of oxygen gas arises mainly due to the low rate of oxygen recombination on the MH electrode surface during charge/discharge cycling. The difference of oxygen recombination rate between $AB_5$ type electrode and Zr-Ti-Mn-V-Ni electrode is caused by the difference of electrode reaction surface area resulting from different particle size after their activation and the difference of surface catalytic activity for oxygen recombination reaction, respectively. After EIS analysis, it is identified that the surface catalytic activity affects much more dominantly on the oxygen recombination reaction than the reaction surface area does. In order to suppress the inner cell pressure of Ni-MH battery where Zr-Ti-Mn-V-Ni is used as anode, it is suggested that the surface catalytic activity for oxygen recombination should be improved.

• 한국식물병리학회지
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• 제13권3호
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• pp.172-178
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• 1997

십자화과 작물에 발생하는 검은썩음병(Black rot or Black vein of crucifer)의 병원성 세균인 Xanthomonas campestris pv. crucifer)의 병원성 세균인 Xanthomonas campestris pv. campestris를 분리, 동정하고 병원성을 검정하였다. 이 X. c. pv. campestris 는 3가지 종의 Chinese cabbage에 병원성을 나타내었고, 병원성과 관련된 특성을 결정하기 위하여 Tn5 mutagenesis를 실시 cellulase negative mutant를 선발하여 병원성 검정하였다. 선발된 cellulase negative mutant를 배추에 분무 접종하여 광학 현미경과 전자현미경으로 관찰한 결과 cellulase negative mutant는 wild type와 함께 기공표면과 기공하부조직에서 정착하였지만 그 밀도는 낮았다. 반면 접종 24시간 이후 wild type은 기공표면과 기공하부조직이 lysis되기 시작하여 48시간 이후에는 병원성의 진전으로 보다 많이 lysis되었다. 6일 후, wild type은 cellulase활성에 의해 식물체 조직에서 높은 증식력을 보이며 조직을 lysis 시키고 또한 조직 깊숙이 침입, 정착하는 것을 관찰하였다. 이 결과로 X. c. pv.c campestris의 cellulase는 병원성에 관여하는 중요한 요인으로 생각된다.

• Archives of Plastic Surgery
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• 제35권5호
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• pp.581-588
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• 2008

Purpose: It is generally accepted that anatomical structures of the soft tissue in Asian faces are quite different from those in Caucasian. It is presumed that these differences are due to collagen rich thick dermis and durable superficial musculo-apponeurotic system (SMAS) in Asian. We classified the aging lower eyelids and reviewed the operative procedures according to the types of aging lower eyelids in Asian. Methods: We compared preoperative and postoperative photos of 117 patients over 30 years of age, who underwent lower blepharoplasty at the Kyunghee Medical Center from January 2001 to April 2006. We classified the patients based on the degree of skin laxity, presence of nasojugal groove and malar bag, the extent of aging process. We also reviewed the operative procedures according to each type of classification. Results: We classified our patients into four types as following. Type I patients showed minimal skin-muscle excess confined to lower eyelids regardless of the facial line. For these patients, we performed only transcutaneous or transconjunctival blepharoplasty. In type II patients, nasojugal grooves were shown and skin- muscle laxity was limited to the medial side of imaginary vertical line at lateral margin of pupil. In these cases, we performed free fat graft or fat repositioning on nasojugal groove or fat removal and septal duplication confined to medial side. Type III patients displayed more advanced medial bulging and remarkable laxity over the lateral side, the same operation methods as those of type II were applied at the lateral side of the line. Type IV patients demonstrated extensive midfacial aging changes including malar bags and underwent superficial subciliary cheek lift. Conclusion: The lower eyelid aging of Asian is different from those of Caucasian. We think that our classification is useful in selection of appropriate operative procedure to address specific problems for Asian patients.

• 대한두개안면성형외과학회지
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• 제10권1호
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• pp.1-6
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• 2009

Purpose: This study presents a classification of pure medial and inferior blow-out fracture, and confirms the relationship between the types of fractures, postoperative complications and operative methods. Methods: Sixty patients were treated by transnasal endoscopic reduction with $Medpor^{(R)}$ implantation through subciliary incision and foley catheter insertion into maxillary sinus was done if there was extensive orbital floor fracture. Fractures were classified by number of coronal sections from posterior margin of fossa for lacrimal sac to orbital apex in CT. Type I is defined when the medial wall fracture is over 50% and inferior wall fracture below 50%. Type II, when below 50% medial wall fracture and over 50% floor fracture were present. If there were both over 50%, it was classified as Type III and both below 50% for Type IV. Extreme fracture involving orbital buttress was Type V and postoperative findings in all patients were examined. Results: Type I and V were most common and preoperative findings were more likely to present according to extent of inferior fracture. Diplopia remained in 2 cases after additional insertion of foley catheter, but enophthalmos over 2 mm were presented in 3 cases and diplopia in 3 cases were observed who were not treated with foley catheter. Conclusion: Postoperative complications were increased according to extent of fracture, especially buttress involvement. Additional insertion of foley catheter proved its effectiveness in decreasing postoperative complications.

• 한국환경생태학회지
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• 제27권6호
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• pp.745-756
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• 2013

본 연구는 옥상녹화 시 식물유형별 수분요구도에 대한 사항을 사전에 고려하여 저관리, 최소한의 관리로 조성되는 옥상녹화의 지속가능성을 유지하고자 하는 데에 목적을 두고 있다. 따라서 옥상녹화의 대표적인 식물로 알려진 세덤류 중 애기기린초와 내건성이 강한 일반 초화류 중 상록패랭이가 동일 조건에서 건조에 견디는 저항력과 토양종류별 토양수분감소에 대한 생육변화를 살펴보고자 실험을 수행하였다. 무관수, 무강우 조건에서 30일 경과 후 상록패랭이가 식재된 펄라이트 10cm 토양이 토양 내 수분함량이 가장 적은 것으로 나타났고, 애기기린초가 식재된 인공배합토 20cm의 토양이 다른 토양에 비해 가장 많은 수분함량을 나타냈다. 또한 전반적으로 토양종류와 토심에 관계없이 애기기린초가 식재된 토양구보다 상록패랭이가 식재된 토양실험구의 수분함량이 낮은 것으로 나타났다. 이는 상록패랭이의 수분요구도가 애기기린초보다 더 크다는 사실을 증명하는 결과라 할 수 있다. 또한 식물의 생육상태는 펄라이트 토양중에서도 토심이 낮은 10cm, 인공배합토양에서도 20cm 실험구보다 10cm 실험구에서 더 양호한 결과가 도출되었다. 본 실험결과 무강우 무관수 조건에서 토양 종류에 따라 토양수분의 감소패턴에 큰 차이가 있음을 알 수 있었으며, 식물 종류에 따라서도 토양수분감소에 따른 수분스트레스 패턴의 차이가 있음을 알 수 있었다.

• 한국환경복원기술학회지
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• 제8권4호
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• pp.12-22
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• 2005

The purpose of this study is to select suitable planting base for the mat-type rooftop greening in order to popularize rooftop greening system easily. The experiment was conducted from 2004 June to 2005 May under several conditions; 4 soil depths under mats(2cm, 5cm, 10cm, 15cm), two soil mixtures(natural soil 80%+leaf mold 20%, artificial soil) and two light conditions(full sun place, 20% shaded place). In this experiment, 3 types of mats were used ; the herbaceous plants mat(11 plants inclusive of Lotus corniculatus L., Silene armeria L.), the lawn mat with Festica arundinacea and Sedum mat with Sedum kamtschaticum, Sedum sarmentosum, Sedum oryzifolium, Sedum middendorffianum. The result is as follows; in the mat-type rooftop greening, the herbaceous plants mat, lawn mat and sedum mat are the similar number of plant and effect of greening on soil depth 2cm, 5cm and 10cm, 15cm. So suitable soil depth of rooftop greening is 10cm for the load and economical factor. Thus the mat-type rooftop greening possible planting base depth of all 13cm as soil depth 10cm and mat depth 3cm. As soil mixtures, the number and growth of plants were better mat and 'natural soil 80% +leaf mold 20%' than mat and artificial soil. In herbaceous plants mat, Silene armeria L., Dianthus chinensis, Centaurea cyanus L., Lotus corniculatus L. are survival in full sun place and Silene armeria L., Dianthus chinensis, Centaurea cyanus L. are survival in 20% shaded place. In conclusion, selection of suitable soil mixtures and plants is possible extensive management rooftop greening with effect of continuous greening. The mat-type rooftop greening are lightweight and simple preparation without management and can popularize readily.

• Archives of Plastic Surgery
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• 제42권5호
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• pp.544-551
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• 2015

Background Changes in the composition of the extracellular matrix (ECM) occur between the proliferating and involuted phases of infantile hemangiomas (IH), and are associated with angiogenic growth. We examined the composition of the ECM in proliferating and involuted IHs and assessed correlations between the composition of the ECM and whether the IH was in the proliferating or the involuted phase. Methods We evaluated IH samples from a cohort of patients who had five proliferating IHs and five involuted IHs. The following ECM molecules were analyzed using enzyme-linked immunosorbent assays and immunohistochemistry: laminin, fibronectin, collagen type I, collagen type II, and collagen type III. Results The involuted IHs had higher levels of deposition of collagen type III than the proliferating IHs. The median values (interquartile ranges) were 1.135 (0.946-1.486) and 1.008 (0.780- 1.166) (P=0.019), respectively. The level of laminin was higher in involuted IHs than in proliferating IHs, with median values (interquartile ranges) of 3.191 (2.945-3.191) and 2.479 (1.699- 3.284) (P=0.047), respectively. Abundant collagen type III staining was found in involuted IHs. Laminin ${\alpha}4$ chain staining was clearly present within the basement membrane adjacent to the blood vessels, and was significantly more intense in involuted IHs than in proliferative IHs. Conclusions Involuted hemangiomas showed extensive deposition of collagen III and laminin, suggesting that differences in the composition of the ECM reflect stages of the development of IHs. This pattern may be due to the rapid senescence of IHs.