• 대한조선학회논문집
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• 제29권1호
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• pp.71-80
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• 1992

국제수조회의(ITTC) 내항성분과에서 회귀현상(rare event)레 대한 시험기법 확립 및 계측기간 결정을 목적으로 19차 ITTC 내항성분과의 공동사업으로 갑판침수 계측시험을 수행한 바 있다. 본 논문에는 공동연구에 참여한 수조시험연구회(KTTC)의 두 회원인 해사기술연구소(KRISO)와 현대선박해양연구소(HMRI)의 실험방법 및 결과를 비교 검토하였다. 선수상대운동과 갑판침수 사이의 상관관계 및 Poisson process에 근거한 계측시간의 추정에 촛점을 두어 결과를 고찰하였다. 동일한 특성을 갖는 입사파에 대해 계측된 갑판침수 빈도수는 두 기관 모두 계측시마다 큰 차이를 보였으며 이는 일반적인 선체운동 계측 보다 더 많은 계측시간이 필요한 것을 의미한다. 선수상대운동과 갑판침수사이의 상관관계는 선수형상, 선속 및 해상상태에 따라 달라지며 본 공동연구의 실험 조건하에서는 (유의파고 7.88m, 선속 22.15노트) 둘 사이의 상관관계가 매우 높은 것으로 나타났다. 또한 갑판침수 현상의 통계적 특성은 Poisson process로 해석될 수 있음을 보였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.243-244
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• 2013

Over the past 15 years, several groups have incorporated radio-frequency quadrupole (RFQ) based instruments before the accelerator in accelerator mass spectrometry (AMS) systems for ion-gas interactions at low kinetic energy (＜40 eV). Most AMS systems arebased on a tandem accelerator, which requires negative ions at injection. Typically, AMS sensitivity abundance ratios for radioactive-to-stable isotope are limited to Xr/Xs ＞10^-15, and the range of isotopes that can be analyzed is limited because of theneed to produce rather large negative ion beams and the presence of atomic isobaric interferences after stripping. The potential of using low-kinetic energy ion-gas interactions for isobar suppression before the accelerator has been demonstrated for several negative ion isobar systems with a prototype RFQ system incorporated into the AMS system at IsoTrace Laboratory, Canada (Ontario, Toronto). Requisite for any such RFQ system applied to very rare isotope analysis is large transmission of the analyte ion. This requires proper phase-space matching between the RFQ acceptance and the ion beam phase space (e.g. 35 keV, ${\varphi}3mm$, +-35 mrad), and the ability to control the average ion energy during interactions with the gas. A segmented RFQ instrument is currently being designed at Korea Institute for Science and Technology (한국과학기술연구원, KIST). It will consist of: a) an initial static voltage electrode deceleration region, to lower the ion energy from 35 keV down to ＜40 eV at injection into the first RFQ segment; b) the segmented quadrupole ion-gas interaction region; c) a static voltage electrode re-acceleration region for ion injection into a tandem accelerator. Design considerations and modeling will be discussed. This system should greatly lower the detection limits of the 6 MV AMS system currently being commissioned at KIST. As an example, current detection sensitivity of 41Ca/Ca is limited to the order of 10^-15 while the 41Ca/Ca abundance in modern samples is typically 41Ca/Ca~10^-14 - 10^-15. The major atomic isobaric interference in AMS is 41K. Proof-of-principal work at IsoTrace Lab. has demonstrated that a properly designed system can achieve a relative suppression of KF3-/41CaF3- ＞4 orders of magnitude while maintaining very high transmission of the 41CaF3- ion. This would lower the 41Ca detection limits of the KIST AMS system to at least 41Ca/Ca~10^-19. As Ca is found in bones and shells, this would potentially allow direct dating of valuable anthropological archives and archives relevant to our understanding of the most pronounced climate change events over the past million years that cannot be directly dated with the presently accessible isotopes.

• 한국환경생태학회지
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• 제32권3호
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• pp.256-260
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• 2018

카니발리즘은 동물계에 널리 알려져 있다. 그러나 조류의 경우 둥지 조사가 아닌 야생에서 관찰되는 경우는 드물다. 이러한 행동은 불규칙적으로 발생할 뿐만 아니라 지속적 관찰이 거의 불가능하기 때문이다. 독수리의 카니발리즘은 2017년 1월 17일 월동지인 해남군 금호호 농경지 주변($34^{\circ}35^{\prime}58.25^{{\prime}{\prime}}N$, $126^{\circ}26^{\prime}57.64^{{\prime}{\prime}}E$) 한 무리의 독수리에서 관찰되었다. 관찰은 현장으로부터 20m 또는 60m 정도 떨어진 곳의 승용차 내에서 쌍안경을 통하여 이루어 졌고, 사진 촬영을 위해 망원렌즈가 장착된 카메라도 함께 사용되었다. 현장에서 취식을 하던 마지막 독수리가 떠난 후 먹이의 잔존물을 확인하였다. 독수리가 취식했던 장소에는 독수리의 몸깃, 두개골, 흉골, 양쪽 다리 등 독수리의 잔존물들이 발견되었다. 그리고 그 외에는 그들의 먹이가 되는 다른 동물의 어떠한 흔적도 발견되지 않았다. 본 연구는 독수리의 카니발리즘에 관한 최초 보고로 카니발리즘에 대한 세부적인 설명 및 그 행동에 영향을 미친 환경적 요인에 대하여 알아보고자 하였다.

• 한국수자원학회논문집
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• 제36권4호
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• pp.691-703
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• 2003

본 논문에서는 유역과 강우특성을 통합하여 오염물질 부하량을 계산할 수 있는 접근방법을 제시하였다. 이 기법의 기본적인 개념은 특정유역에서 강우시 발생하는 오염물질의 유량 가중평균 농도, 즉 EMC 변화는 오로지 강우패턴에 의해 결정된다는 가정에 기초하고 있다. 이러한 가정은 적어도 유역의 토지이용에 급격한 변화가 없고(적어도 강우가 집중되는 경작기간동안) 점 오염원이 적은 농촌유역에서는 타당하다. 따라서, 다양한 농촌유역과 강우 패턴 조건에서 조사된 많은 EMC 자료가 있다면 EMC와 토지이용, 그리고 강우특성 사이의 유용한 경험적인 관계식을 도출할 수 있을 것이다. 이러한 목적을 달성하기 위하여 9개의 서로 다른 유역에서 51개의 독립적인 강우사상에서 조사된 EMC 자료를 이용하여 강우시 발생하는 EMC 값을 예측할 수 있는 도구를 개발하였다. 통계학적인 검토결과 개발된 경험식은 실제 측정한 EMC 값을 양호한 수준에서 예측할 수 있는 것으로 판명되었을 뿐만 아니라 EMC 자료와 유효 강우량에 기초하여 강우일, 주, 월, 년 단위의 부하량을 산출이 가능하였다. 또한, EMC 값과 유효 강우량에 의해 계산된 부하량으로부터 산출한 원 단위를 기존의 잘 알려진 경험적 원 단위와 비교 평가하였다.

• 대한두경부종양학회지
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• 제24권1호
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• pp.33-42
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• 2008

Head and neck squamous cell carcinoma(HNSCC) is notorious for its poor outcome and increasing incidence. But, the studies of cytogenetic analysis in HNSCC are relatively rare, because of difficulties in culturing solid tumor cells and complexity in chromosomal DNA abberations associated with the lesions. The purpose of this study is to evaluate the location of chromosomal aberrations in Korean HNSCC cell lines (SNU-1041, 1066, and 1076) with comparative genomic hybridization(CGH) and array based CGH(array-CGH). Chromosomal gains of 3q23-q27, 5p13-p15.3, 7p21-pter, 8q11.2-q12, 8q21.1-qter, 9q22-q34, 16q22-q24, and 20q11.2-qter, as well as chromosomal losses on 3p10-p14 were found in all 3 SNU cell lines. Losses on 3p15- p23, 4q22-q27, 4q31.3-qter, 6q14-q15, 7q31-q34, 8p12-pter, 18q21-q23, and 21q11.2-q12 were observed in 2 of 3 cell lines. In array-CGH, many genes were altered including gains of PIK3CA, MYC, EVI1, MAD1L1 genes and losses of SERPIN genes. These aberrations of gene and chromosome coincide with other results of study, generally. These data about the patterns of chromosomal aberrations could be a basic step for understanding more detailed genetic events in the carcinogenesis and also provide information for diagosis and treatment in HNSCC.

• The Korean journal of internal medicine
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• 제33권6호
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• pp.1111-1118
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• 2018

Background/Aims: Chest pain is an essential symptom in the diagnosis of acute coronary syndrome (ACS). One-third of patients with ACS present atypically, which can influence their receiving timely lifesaving therapy. Methods: A total of 617 NSTEMI patients from the Korea Acute MI Registry (KAMIR) and the Korea Working Group on MI (KorMI) databases were analyzed. The study population was divided into two groups by symptoms at presentation (typical symptoms group, 128; atypical symptoms groups, 128). Results: In this study population, 23% of patients presented without chest pain. After propensity score matching, the contact-to-device time ($2,618{\pm}381minutes$ vs. $1,739{\pm}241minutes$, p = 0.050), the symptoms-to-balloon time ($3,426{\pm}389minutes$ vs. $2,366{\pm}255minutes$, p = 0.024), and the door-to-balloon time ($2,339{\pm}380minutes$ vs. $1,544{\pm}244minutes$, p = 0.002) were significantly higher in the patients with atypical symptoms than in those with typical symptoms, respectively. Atypical symptoms were an independent predictor for 1-year mortality (hazard ratio, 2.820; 95% confidence interval, 1.058 to 7.515; p = 0.038). The Kaplan-Meier estimates showed higher risk for 12-month mortality in patients with atypical symptoms (p = 0.048) and no significant difference for 12-month major adverse cardiac events (p = 0.487). Conclusions: Acute myocardial infarction patients with atypical symptoms were not rare in clinical practice and showed a high risk of delayed reperfusion therapy. After imbalance between the groups was minimized by use of propensity score matching, patients who presented atypically had a high mortality rate.

• Journal of Korean Neurosurgical Society
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• 제62권4호
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• pp.450-457
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• 2019

Objective : Anterior cervical discectomy and fusion (ACDF) is commonly used surgical procedure for cervical degenerative disease. Among the various intervertebral spacers, the use of allografts is increasing due to its advantages such as no harvest site complications and low rate of subsidence. Although subsidence is a rare complication, graft collapse is often observed in the follow-up period. Graft collapse is defined as a significant graft height loss without subsidence, which can lead to clinical deterioration due to foraminal re-stenosis or segmental kyphosis. However, studies about the collapse of allografts are very limited. In this study, we evaluated risk factors associated with graft collapse. Methods : We retrospectively reviewed 33 patients who underwent two level ACDF with anterior plating using allogenous bone graft from January 2013 to June 2017. Various factors related to cervical sagittal alignment were measured preoperatively (PRE), postoperatively (POST), and last follow-up. The collapse was defined as the ratio of decrement from POST disc height to follow-up disc height. We also defined significant collapses as disc heights that were decreased by 30% or more after surgery. The intraoperative distraction was defined as the ratio of increment from PRE disc height to POST disc height. Results : The subsidence rate was 4.5% and graft collapse rate was 28.8%. The pseudarthrosis rate was 16.7% and there was no association between pseudarthrosis and graft collapse. Among the collapse-related risk factors, pre-operative segmental angle (p=0.047) and intra-operative distraction (p=0.003) were significantly related to allograft collapse. The cut-off value of intraoperative distraction ${\geq}37.3%$ was significantly associated with collapse (p=0.009; odds ratio, 4.622; 95% confidence interval, 1.470-14.531). The average time of events were as follows: collapse, $5.8{\pm}5.7months$; subsidence, $0.99{\pm}0.50months$; and instrument failure, $9.13{\pm}0.50months$. Conclusion : We experienced a higher frequency rate of collapse than subsidence in ACDF using an allograft. Of the various preoperative factors, intra-operative distraction was the most predictable factor of the allograft collapse. This was especially true when the intraoperative distraction was more than 37%, in which case the occurrence of graft collapse increased 4.6 times. We also found that instrument failure occurs only after the allograft collapse.

• 대한토목학회논문집
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• 제28권4B호
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• pp.393-403
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• 2008

양양 산불 피해 지역 당해년도의 극심한 지표 변화에 따른 지표유출 및 토양침식을 분석하기 위해 산불 산지사면에 10개의 소규모 조사구를 설치하여, 지형, 토양, 식생, 강우사상별 유출 및 토양침식량을 측정하였다. 조사는 총 15개 단일강우사상을 기준하여 이루어졌다. 산불이후 식생회복이 빠른 지역과 그렇지 않은 사면의 유출 및 토양침식량은 매우 큰 차이를 보였다. 식생회복이 빠른 조사구들은 대조구보다 약 2배 많은 평균 유출량 및 토양침식량을 나타냈으나, 나지상태 조사구들에서는 대조구의 약 10배 이내의 유출 및 토양침식이 발생되었다. 지표유출 및 토양침식에 대한 주요 인자들과의 상관분석에 의하면 강우인자 및 식생인자는 유출과 토양침식에 상당한 영향을 미쳤다. 유출 및 토양침식 민감도는 식생지수들과 높은 상관성을 보였다. 산불에 의해 교란된 지표식생이 시간이 경과함에 따라 회복되고, 산불초기에 다량의 토사유출이 발생된 이후 사면 토양의 안정화에 따라 전반적으로 유출 및 토양침식량이 감소하였다. 그러나 식생회복이 안되거나, 식생회복이 더딘 지역은 지속적으로 유출 및 토양침식이 발생하기 때문에 산불 지역별로 차별화된 대응전략 수립이 필요하다.

• 대한환경공학회지
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• 제34권11호
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• pp.720-728
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• 2012

강우시 상당 부분의 비점오염물질은 입자성물질에 흡착된 형태로 유출되기 때문에 비점오염물질의 유출 거동을 보다 정확하게 이해하기 위해서는 입자성물질과의 상관성을 정량적으로 파악하는 것이 중요하다. 그러나 강우시 오염물질별 유출특성과 입도분포와의 상관성에 대한 연구사례는 매우 부족한 실정으로, 특히 도시화가 진전되지 않은 비시가화지역을 대상으로 한 국내 연구는 보고된 예가 거의 없다. 본 연구에서는 논, 밭 및 임야 등으로 구성된 소규모 비시가화지역(유역면적 52.8 ha)을 선정하여 다양한 규모의 강우사상별 유출특성을 조사하고, 오염물질의 유출특성과 입자성물질의 거동 사이의 상관관계를 분석하였다. 또한, 비점오염물질의 유출에 미치는 입자성물질의 영향에 대하여 정량적인 분석을 실시하였다. 연구결과, 중소규모 강우에서도 초기유출현상이 관찰되었으며, 입자성물질이 영양염류 및 중금속의 유출과정에 큰 기여를 하고 있는 것으로 나타났다. 특히, $BOD_5$와 TOC의 유기물항목, TN과 TP의 영양염류, Al, Cr, Cu, Fe, Hg 및 Zn의 중금속항목 등이 SS (total), VSS, SS (d < $20{\mu}m$) 및 SS ($20{\mu}m$ $$\leq_-$$ d < $80{\mu}m$)와 높은 상관성을 보여 입자성물질과 유사한 유출거동을 갖는 것으로 나타났다. 한편, $COD_{cr}$, Cd, Mn 및 Pb는 입자성물질의 유출거동과 뚜렷한 상관성을 보이지 않았다. 비시가화지역에서 비점오염물질의 유출과정은 입자성물질의 거동과 상관성이 높을 뿐만 아니라 처리대상물질에 따라서도 상이한 특성을 갖는다는 점을 고려한 비점오염 저감시설의 도입이 이루어져야 할 것으로 판단된다.

• 복식문화연구
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• 제3권2호
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• pp.241-260
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• 1995

The Maori's traditional clothing materials, basic forms of dress, and the pattern and technique of tatoo were examined in the present study in order to deepen the appreciation of the cultural heritage of the Maori. The research method employed was the analysis of written materials. And a fild-trip was also made for the study. The study was limitted to the traditional culture of body adornment of the Maori including the clothing which is preserved and practicing by them at the present day, and the origin and the process of the historical development of those are not included in the scope of the present study. Followings are the results of the study: (1) By far the most widely used fiber for Maori clothing is abtained from what is commonly called New Zealand Flax. The fiber of kiekie(Freycinetia baueriana) and cabbage trees(Cordyline spp.) may also be used. The strong, long-lasting fiber of toi(cordyline indivisa) is used for a prestige warrior's cloak. Flat strips of ti kauka(Cordyline australi) are also used as thatch on rain cloaks. (2) Regardless of technique used, Maori weaving is always worked horizontally from left to right. Traditionally the work was suspended between two upright turuturu or weaving sticks. As the work progressed a second pair of uprights was used to keep the work off the ground. These uprights were moved forward as required. Because the weaver sat on the ground, the working edge was kept at a height that was comfortable to reach. No weaving tools are used, the wefts(aho) being manipulated by the fingers. The two main Maori weaving techniques are whatu aho patahi(single-pair twining) and whatu aho rua(double-pair twining). (3) The Maori wore two basic garments - a waist met and a cloak. The cloth of commoners were of plain manufacture, while those of people of rank were superior, sometimes being decorated with feather or dyed tags and decorated borders. Children ran more-or-less naked until puberty, being dressed only for special events. Some working dress consisted of nothing more than belts with leaves thrust under them. Chiefs and commoners usually went barefoot, using rough sandals on journeys over rough country (4) The adornment of men and women of rank was an important matter of tribal concern as it was in chiefly persons that prestige of the group was centred, The durable items of Maori persons adornment were either worn or carried. Ornaments of various kinds were draped about the neck or suspended from pierced earlobes. Combs decorated the head. Personal decorations not only enhanced the appearance of men and women, but many had protective magical function. The most evident personal ornament was the hei-tiki made of jade or other material. Maori weapons were treasured by their owners. They served on bottle and were also personal regalia. A man of rank was not fully dressed without a weapon in hand. Also weapons were essential to effective oratory. (5) No man or woman of rank went without some tattoo adornment except in extremely rare instances when a person was too sacred to have any blood shed. The untattooed were marked as beeing commoners of no social standing. This indelible mark of rank was begun, with appropriate rite and ritual, at puberty. And tattoo marked the person as being of a marriageable age. Maori tattoo was unlike most traditional tattoo in that its main line were 'engraved' on the face with deep cuts made by miniature bone chisels. The fill-in areas were not tattooed with cuts but with the multiple pricks of small bone 'combs' that only lightly penetrated the skin surface. The instrument of tattoo consisted of small pots of pumice or wood into which was placed a wetted black pigment made from burnt kauri gum, burnt vegetable caterpillars or other sooty materials. A bird bone chisel or comb set at right angles on a short wooden handle was dipped into the gigment, that a rod or stick was used to tap head of this miniature adze, causing penetration of the skin surface. Black pigment lodged under the skin took on a bluish tinge. A full made facial tattoo consisted of major spirals with smaller spirals on each side of the nose and sweeping curved lines radiating out from between the brows over the forehead and from the nose to the chin. The major patterns were cut deep, while the secondary koru patterns were lightly pricked into the skin.