목재 및 목질재료용 난연성 폴리우레탄수지 도막의 난연성능

김종인,박종영,이병후,김현중,노정관,공영토 한국목재공학회 2002 목재공학 Vol.30 No.2

본 연구에서는 MDF와 잣나무 판재에 대한 난연처리 및 난연도장 처리 시험편에 대한 난연 효과에 대해 고찰하였다. 무처리 MDF와 잣나무판재에 대한 tdθ은 각각 279.5, 182.5로 나타났으나 난연침지 처리된 무늬단판을 오버레이한 MDF를 난연도장 처리 한 경우 높은 난연성능을 나타냈다. 난연처리한 잣나무판재에 난연도장처리를 할 경우 tdθ가 90으로 나타났고, 난연침지 처리 된 무늬단판이 오버레이 된 MDF에 난연도장처리 한 경우에는 tdθ가 0으로 나타난 가장 뛰어난 난연성능을 나타냈다. 전체적으로 난연처리 및 난연도장처리를 한 경우 tdθ가 감소하는 것으로 나타나 난연성능이 개선되는 것으로 나타났다. 또한 연소도 시험결과 시험편의 중량감소율은 난연처리와 난연도장처리에 의해 감소함으로써 난연성능이 개선되는 것으로 나타났다. 또한 착화시간과 잔염시간의 측정결과도 유사하게 나타났으며 난연침지 처리 된 무늬단판이 오퍼레이 된 MDF 및 난연처리된 잣나무판재에 난연도장 처리한 경우 무처리된 경우에 비해 착화시간은 증가되고, 잔염시간은 감소하는 것으로 나타났다. In this study, two materials treated with a flame retardant were examined for their fire resistance. The first, MDF(medium density fiberboard) was overlaid by an oak sliced veneer, which was either treated by soaking in a 6wt.% solution of flame retardant chemicals (pentabromine-chlorinated paraffin) or non-treated and then was coated with either a flame retardant polyurethane coating or with a common polyurethane coating. The second material, Pinus koraiensis penal was either treated by a spray treatment using a flame retardant solution or non-treated and then was coated with either a flame retardant polyurethane coating or with a common polyurethane coating. Pentabromine-chorinated paraffin chemicals were added (6 part of urethane resin) as the flame retardant chemicals in the polyurethane coatings. In the fire resistance test, the tdθ(℃·min.) decreased with the flame retardant treatment or/and the flame retardant coatings, compared to the untreated sample. Weight loss (%) decreased with the flame retardant treatment or/and the flame retardant coatings. The ignition time (sec.) increased and the residual flame time (sec.) decreased with the flame retardant treatment or/and flame retardant coatings. Therefore, the flame retardant treatment or/and flame retardant polyurethane coatings have excellent incombustibility.

Meckel 게실의 합병증으로 수술 받은 환아의 임상양상

김현아,최금자,한후재 이화여자대학교 2003 EMJ (Ewha medical journal) Vol.26 No.2

Objectives : The purpose of study is to assess the clinical characteristics of complicated Meckel's diverticulum in children. Methods : A retrospective review of pediatric cases of complicated Meckel's diverticulae that were surgically treated at Ewha Womans University Hospital from 1985 was performed. The charts were reviewed for the age and sex of the patients, operation finding, treatment, and outcome. Results : A total 13 patients with a complicated Meckel's diverticulum were identified. There were 8 boys(61.5%) and 5 girls (38.5%) with a mean age of 5.3 years (range, 1month to 14years). Presenting signs and symptoms included digestive hemorrhage (6), intestinal obstruction(4), perfora-tion (1), intussusception due to inverted Meckel's diverticulum (1) and diverticulitis (1). A ^(99m) technetium pertechnetate scintiscan was positive in 3 of 4 patients. Barium contrast studies and colonoscopys were not diagnostic. The mean distance from the ileocecal valve to the diverticulum was 47.0±15.7cm. Average length of the diverticulum was approximately 4.7±3.0cm. Segmen-tal small bowel resection including Meckel's diverticulum (84.6%) or wedge excision(15.4%) was done for treatment. In the bleeding group, ectopic gastric mucosa was present in 5 of 6 patients. Postoperative morbidity and mortality was each 0%. Conclusion : The results of this study draw attention to the fact that the complicated Meckel's diverticulum must be suspected in children with acute abdomen or gastrointestinal bleeding. 목적: Meckel 게실의 합병증의 원인이 되어 수술적 치료를 받은 소아 환자들의 임상적 증상과 수술소견, 병리학적 소견을 분석하여 이들의 특징을 알아보고자 하였다. 방법 : 1985년 이후 이화대학교의료원에서 Meckel 게실의 합병증으로 수술을 받은 15세 이하의 소아들 대상으로 하여 의무기록과 조직병리 검사 결과를 조사하였다. 결과: 총 13명의 환아가 Meckel 게실의 합병증으로 수술을 받았으며 남녀의 비는 1.6:1로 남아에서 호발하는 경향을 보였으며, 수술 시 평균 연령은 5.3세였다. 수술의 원인이 된 Meckel 게실의 진단은 장출혈 6예, 장폐색 4예,Meckel 게실의 천공 1예, 장중첩 1예, 게실염 1예였다. 회맹판에서 게실까지의 평균길이는 47.0±15.7cm이었으며, 소장부분절제술과 쐐기절제술이 각각 84.6%와 15.4%에서 시행되었다. 장출혈을 나타내었던 환아 6명 중 5예에서 병리조직에서 이소성 위 점막이 관찰되었다. 술 후 합병증과 사망예는 없었다. 결론 : 소아에서 외과적 급성 복증이나 장출혈의 증상이 나타날 경우, Meckel 게실의 합병증의 가능성에 대한 외과의의 인식이 필요하다.

굴절 토모그래피를 이용한 터널부지 지반조사

김진후,김현도 동아대학교 해양자원연구소 2000 硏究論文集 Vol.13 No.1

Determining the depth and geometry of a sub-surface structure is a difficult task, especially in the steep and rugged mountain where even a drilling machine cannot be carried and installed on it. Potential field methods generally lack the necessary depth resolution, and seismic reflection data are much influenced by complex geometry of the structure. To address this problem, we have applied a surface 2-D tomographic refraction scheme that is based on an inversion method that incorporates appropriate damping and smoothing constraints. This scheme has been applied to a first-arrival traveltime data set collected over a tunnel route. Seismic data were collected along 10 profiles, and each profile consists of 5 shots and 24 receivers. Reliability of the resultant velocity tomograms were estimated on the basis of (1) plots of the difference between synthetic and observed traveltime (traveltime residual analysis), and (2) RMS errors with diverse input models. The sub-surface structure can be grouped in 2 layers, i.e. soil/weathered rock and basement. The thickness of the near-surface natural soil/weathered rock layer varied between 0 and 10 m, with occasional thickening to 30m. The depth to the basement could be traced to 9~11 m. Several low velocity zones which are developed in vertically have been found along the profiles. The low velocity zones are considered as weak and fracture zones, so that appropriate supporting methods must be considered when planning and great attentions must be paid during tunneling.

합성 탄성파 자료에 대한 디콘볼류션 적용에 관한 연구

김진후,김현도 東亞大學校 海洋資源硏究所 2003 硏究論文集 Vol.15 No.-

One of the main techniques for data processing of a high resolution shallow seismic survey is the deconvolution. By using deconvolution technique, compression of the basic wavelet and removal of multiples can be achieved. In this study it can be concluded that the details of the formation structure can be obtained through applying predict error deconvolution to a synthetic seismogram. In applying deconvolution determination of the operator length and predict lag is critical, and the output resolution relies on them. It is also concluded that when the predict lag is short, compression of the basic wavelet is anticipated, and when the predict lag is long, multiples can be decayed,

스파커 음원을 이용한 고해상 다중채널 해양 탄성파탐사

김진후,김현도 東亞大學校 海洋資源硏究所 2006 硏究論文集 Vol.18 No.-

A sparker source with the center frequency of 1㎑ or higher can not be easily applied for the multi-channel marine seismic survey because of stacking difficulties. Thus, it has been applied mainly to the single channel marine seismic survey. For examining the applicability of sparker source to multi-channel marine seismic survey, 8-channel seismic data were obtained from the field and processed, and a 2-D seismic section was drawn up. From this study it can be concluded that, a sparker source with the center frequency of 1㎑ or higher can be applied to the multi-channel marine seismic survey, and the seismic section with high vertical resolution can be generated. The high-resolution seismic section would be very useful for subsurface geological structure analysis in the shallow sea.

탄성파 속도를 이용한 암종분류에 관한 연구

김진후,김현도 東亞大學校 海洋資源硏究所 1999 硏究論文集 Vol.12 No.1

Down-hole seismic surveys and cross-hole seismic surveys have been used for rock type classification. For rock type classification, such as soft rock, medium rock, hard rock, and very hard rock, the moisture content effect on wave velocities in in-situ rock mass is considered and a new classification criterion is proposed. With an appropriate rock type classification the volume of each rock type can be obtained by trapezoidal rule of integration. The volume of each rock type can be used for estimating amount of work for ripping and blasting when a construction site is being prepared.

5성분 지오폰의 다운홀 탄성파탐사 적용 가능성 연구

김진후,김현도 東亞大學校 海洋資源硏究所 2002 硏究論文集 Vol.14 No.1

A new 5-component borehole geophone is proposed and tested for down-hole seismic surveys. Since the traditional borehole geophone is designed to measure 3 components of movement, i.e., 2 horizontal components(x and y directions) and one vertical component(z direction), it is difficult to identify S-wave arrivals when one of the horizontal geophone is not in the same plane with the direction of the strike on the surface. In order to overcome those difficulties and to measure incoming of S- wave in many directions the proposed 5-component borehole geophone consists of one vertical geophone and 4 horizontal geophones which are oriented 45 degrees apart. Also, the 5-component borehole geophone has air packer at the lower part of the borehole in order to stick the geophone to the borehole wall when measuring. A field test was conducted at Eulsookdo test site, and the results show that using a 5-component geophone for down-dole seismic survey is superior to conventional 3-component geophone in identifying S-wave arrivals, and it can be applied to develop a seismic cone, one of the in-situ soil instruments measuring rigidity modulus of soil without a borehole.

해양 탄성파탐사 자료취득을 위한 PC기반 아날로그 신호처리기의 활용 가능성 연구

김진후,김현도 東亞大學校 海洋資源硏究所 2005 硏究論文集 Vol.17 No.-

This paper examines the availability of analog processor for PC to implement the data acquisition system of multi-channel marine seismic survey on a PC base. The analog processor has analog gain and the low cut filtering functions. In this study the data have been acquired by using only the analog gain function. With applying gain function it is observed that the analog signal has the enough energy level and allowable S/N ratio for digitalization. A 2-D seismic section was created using the acquired data and it could be fully utilized for the seismic interpretation. It can be concluded that the analog processor for PC used in data acquisition system for PC based multi-channel marine seismic survey provides the highly economic and effective survey system.

이미지 색상 추출법에 의한 정밀 심도 추출

김진후,김현도 東亞大學校海洋資源硏究所 2004 硏究論文集 Vol.16 No.-

Digitally acquired maine seismic data contain a variety of noises. Among these swell effect, which has occurred according to weather condition, must be removed because the noises affect seismic section in a various ways. Moving average method and high cut filtering method have been used for compressing swell effects as a data processing technique in a marine seismic survey. In order to apply swell effects removal techniques effectively, an accurate bottom detection method must be provided first. Recently, maximum amplitude method and cross-correlation method have been developed for bottom detection, but the accuracy of the bottom detection is largely affected by inherent noises. The proposed image color reduction method with 16 colors, when compared with respect to number of colors, gives simplified color section and very accurate bottom detection. It is concluded that we can remove swell effects more accurately by applying sea bottom data obtained by image color reduction method in the filtering process.

해양탄성파탐사를 이용한 천해저 지층 분석

김진후,박경원,김현도 동아대학교 해양자원연구소 2000 硏究論文集 Vol.13 No.1

A marine seismic exploration with the 400Hz bubble pulser 1200 system was carried out The seismic survey was conducted along the 5 survey lines(total length of 4km), and the aim of this survey was to profile depth of sediment layer and bedrock with SINCDAS(Single Channel Data Acquisition System) developed by this study. The field data is displayed with variabel-density method and compared with borehole log to confirm accuracy of seismic data interpretation. The subsurface structure consists of the upper clay layer and the lower silt-clay layer. But the bedrock depth is not found because of extremely shallow survey depth and multiple reflections.