국산규조토여과조제가 Cake Filtration 의 특성에 미치는 영향

윤석호,나종복,조원선 한국화학공학회 1989 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.27 No.4

국산규조토여과조제를 사용하여 cake filtration에서 filter cake의 공극률과 국소여과비저항이 filter cake에 가해지는 압력에 따라 변화하는 특성을 filter cell에서 실험적으로 고찰하였다. 실험에 사용된 시료는 탄산칼슘, Talc(I) 및 Talc(II) 슬러리와 규조토여과조제였으며 여과조제는 body feeding및 precoating하여 사용하였다. 실험결과 압력이 증가함에 따라 filter cake의 공극률은 감소하였고 국소여과비저항은 증가하였다. 여과조제를 첨가하면 filter cake의 공극률이 증가되어 국소여과비저항을 줄일 수 있다. Variations of porosity and specific local filtration resistance in cake filtration were studied in a filter cell. Samples used were slurries of CaCO₃, Talc(I) and Talc(II) and diatomite filter aids, which were used by body feeding and precoating. From the experimental result, the porosity of filter cake decreased and the specific local filtration resistance increased with increasing pressure. The addition of filteraids increased the porosity of filter cake and it resulted in decreasing the specific local filtration resistance.

하지에 발생한 피부 지방종성 신경섬유종의 치험례

윤석호,정성노,권호 대한성형외과학회 2009 Archives of Plastic Surgery Vol.36 No.4

Purpose: Cutaneous lipomatous neurofibroma is a rare variant of neurofibroma. Histologically, it includes adipose tissue. As far as we aware, only 11 cases of this variant were reported which was predominantly on head, neck and trunk. Hence we present a case of left pretibial area with literature review. Methods: The patient was a 17-year-old female who showed a non-tender, protruding 4×4×2cm sized mass on the left pretibial area for several months. We totally excised the mass including skin and the subcutaneous fat layer. Results: Pathologic report showed cutaneous lipomatous neurofibroma which was well circumscribed and noncapsulated neoplasm present with focal fatty change. Adipose cells were entrapped in the whirls of spindle cells. There were no lipoblasts or atypical adipocytes. Conclusion: A cutaneous lipomatous neurofibroma on the lower extremity is very rare. In our patient, there were no trauma-related histopathologic changes. Therefore, focal fatty change can be a consequence of metaplasia from multipotential neural cells after migration.

Vascularized Bipedicled Pericranial Flaps for Reconstruction of Chronic Scalp Ulcer Occurring after Cranioplasty

윤석호,범진식,양원용,강상윤 대한성형외과학회 2013 Archives of Plastic Surgery Vol.40 No.4

Background Intractable chronic scalp ulcers with cranial bone exposure can occur along the incision after cranioplasty, posing challenges for clinicians. They occur as a result of severe scarring, poor blood circulation of the scalp, and focal osteomyelitis. We successfully repaired these scalp ulcers using a vascularized bipedicled pericranial flap after complete debridement. Methods Six patients who underwent cranioplasty had chronic ulcers where the cranial bone, with or without the metal plate, was exposed along the incision line. After completely excising the ulcer and the adjacent scar tissue, subgaleal dissection was performed. We removed the osteomyelitic calvarial bone, the exposed metal plate, and granulation tissue. A bipedicled pericranial flap was elevated to cover the defect between the bone graft or prosthesis and the normal cranial bone. It was transposed to the defect site and fixed using an absorbable suture. Scalp flaps were bilaterally advanced after relaxation incisions on the galea, and were closed without tension. Results All the surgical wounds were completely healed with an improved aesthetic outcome,and there were no notable complications during a mean follow-up period of seven months. Conclusions A bipedicled pericranial flap is vascularized, prompting wound healing without donor site morbidity. This may be an effective modality for treating chronic scalp ulcer accompanied by the exposure of the cranial bone after cranioplasty.

아치형 비닐하우스 구조의 해석정밀도에 따른 좌굴특성 연구

윤석호,Yoon, Seok-Ho 한국공간구조학회 2015 한국공간구조학회지 Vol.15 No.4

The construction of vinyl greenhouses are increasing because of economic feasibility, construction period, and construction regulations. However, the vinyl greenhouses are apt to collapse by snow load since they have a small member as a temporary structure. The 3 types of buckling such as global, member and nodal buckling could be occurred to arched structures according to characteristics of cross section. To examine the member buckling, the precision of analysis need to be enhanced. In that case, we can examine the characteristics of the those buckling. The purposes of this study are to verify buckling characteristics of structures using the method of high precision analysis with a center node of member. The results of high precision analysis bring member buckling, and in the analysis method having the center node of member, the value of strength is getting lower than a previous study.

OFDM 시스템에서 PAR을 줄이는 SMOPT 기법

윤석호,유승수,김선용,송익호 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.4

논문 데이터베이스를 위한 텍스트 기반 유사도 계산 방안

윤석호,김상욱,Yoon, Seok-Ho,Kim, Sang-Wook 한국정보처리학회 2011 정보처리학회논문지D Vol.18 No.5

This paper addresses computing of similarity among papers using text-based measures. First, we analyze the accuracy of the similarities computed using different parts of a paper, and propose a method of Keyword-Extension, which is very useful when text information is incomplete. Via a series of experiments, we verify the effectiveness of Keyword-Extension. 본 논문에서는 기존 텍스트 기반 유사도 계산 방안을 이용해서 논문들 간의 유사도를 계산하는 방안에 대해서 논의한다. 먼저, 실험을 통해서 논문의 제목, 요약, 그리고 본문 중에서 어떤 부분이 유사도를 계산하는데 더 유용한지 확인하고 적절한 가중치를 부여한다. 두 번째로 논문의 텍스트 정보가 불완전한 상황에서 논문들 간의 유사도를 보다 정확하게 계산할 수 있는 키워드 확장 방안을 제안한다. 실제 논문 데이터베이스를 이용해서 제안하는 방안의 우수성을 검증한다.

액티브클램프 포워드 컨버터 제어기 특성에 관한 연구

윤석호 김천대학교 2008 김천대학교 논문집 Vol.29 No.-

This paper compared to the operation performance and efficiency of an inter-leaved active clamp ZVS forward converter and an interleaved ZVS half-bridge converter in distributed power system. The design for the current-mode control circuit of an interleaved active clamp ZVS forward converter is presented. To simplify the gate drive circuits, N-P MOSFETS coupled active clamp method is proposed. An efficiency about 90% for the 50-100% load range is achieved

제1회 SICHEM '88 SYMPOSIUM 을 마치고

윤석호 한국화학공학회 1989 NICE Vol.7 No.1

정보통신 / 유비쿼터스 컴퓨팅 ; 닷넷스마트클라이언트의 TPC-H 벤치마크

윤석호,이정훈,이병수,이우기 한국경영정보학회 2005 한국경영정보학회 학술대회논문집 Vol.2005 No.-

스팬 300m 구형래티스 돔의 형상과 하중조건에 따른 안정성 검토

윤석호,이동우,정환목 한국복합신소재구조학회 2017 복합신소재구조학회논문집 Vol.8 No.4

In recent years, single layer latticed domes have attracted many designers and researchers’s attention all over the world, because single layer latticed domes as space structure are of great advantage in not only mechanical rationality but also function, fabrication, construction and economic aspect. Yamada developed the shape factor S which represents the shape of spherical latticed dome from a structural perspective as well as a geometric perspective. According to a prior study, the structural behavior and the buckling characteristics of the latticed dome were mostly noticeable when the shape factor of latticed dome was in the range of 1.5 to 5. That is, S, in the range of 1.5 to 5, are able to estimate not only overall buckling, but also member buckling and nodal buckling. In this study, we developed shape models using various size of members with the fixed rise-span ratio. One particular characteristic of the latticed dome is that it is not only light in weight but also high in strength. But the aiming at the use of light-weight materials and at the minimized section of members may result in buckling to cause an unstable state of the overall structure when the external force reaches a limitation. Especially, the structural strength is disadvantageous to the snow loads than the earthquake loads because of light-weight, and is greatly affected by the conditions of loading. This paper is to develop the structural stability according to the shapes and load conditions for single-layer latticed spherical dome with 300m span.