• 한국재료학회지
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• 제10권3호
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• pp.179-183
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• 2000

$BCI_3/H_2/Ar$ ICP(Inductively Coupled Plasma)를 이용한 GaN이 건식식각에 있어서 공정변수들이 식각 특성에 미치는 영향을 분석하고 적정조건을 도출하였다. 연구 결과 식각속도와 측벽수직도 공히 ICP 전력, bias 전압과 $BCI_3$ 조성의 증가, 공정압력의 감소에 의해 현저히 증가하며, 온도의 증가에 따라 다소간 증가하였고, 온도의 증가에 따라 다소간 증가하였고, $BCI_3$조성이 가장 큰 영향을 미쳤다. 표면거칠기는 bias 전압 증가에 의해 크게 향상, $BCI_3$ 조성의 감소에 따라 향상되었으며 다른 변수는 큰 영향을 미치지 않았다. 결과적으로 ICP 전력 900W, bias 전압 400V, $BCI_3$ 조성 60%, 공정압력 4mTorr의 조건에서 175nm/min 정도의 $CI_2$ 사용 시와 유사한 높은 식각속도와 평탄한 표면이 얻어졌다. Bias 전압이 낮은 경우 식각 후 시료 표면에 $GaC_x$로 추정되는 식각부산물이 관찰되었다.

• Journal of Chest Surgery
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• 제30권2호
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• pp.236-240
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• 1997

긴 간격(longgap)의 A형 식도 폐쇄증을 가진 신생아의 치료는 복잡하고 아직까지 이견이 많아, 본래의 식도나 위, 소장, 대장 등을 이용한 치환술로 다양한 식도 재건술이 시행되고 있다. 저자는 long gap의 A형 식도 폐쇄증을 가진 재태기간 28주, 체중 1.2kg의 미숙아에서 식도 단단문합술을 시행하여 좋은 결과를 얻었기에 문헌고찰과 함께 보고하는 바이다. 1차 처치로 위루술를 하고 2차로 식도 단단문합을 시행하였다. 술후 제한된 문함부유출과 종격동염이 발생하였으나 흉관을 통한 적절한 배액(drainage)과 동시에 위루술을 통하여 문합부유출부위에 음압 (negative pressure)을 걸어 지속적 인 흘인(suction)으로 치료하여 호전되었다. 환아는 건강하게 퇴원하였으며 술후 4개월이 지난후 5.4kg으로 체중의 증가가 있었다.

• 한국농공학회지
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• 제34권4호
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• pp.48-58
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• 1992

This study was conducted to investigate the consolidation characteristics of the marine clay, treated with predetermined ratios of lime and briquette ash. The standard consolidation test was performed for the sample of mixture remoulded under the condition of optimum moisture content. The results obtained were as follows ; 1.The increase of the consolidation coefficient due to load increament was larger in the lime treated soil and briquette ash treated soil than in the untreated soil. The decrease of the compression index due to admixing ratio of additives was smaller in the former than in the latter. 2.The increase of the secondary consolidation coefficient of the untreated soil due to load increment was minimal, while that of lime treated soil and the lime-briquette ash treated soil was conspicuous and that of briquette ash treated soil was slight. 3.The $C\alpha$/Cc relationship of untreated soil was represented by colsely distributed points. That of briquette ash treated soil, lime treated soil and the lime-briquette ash treated soil was represented by linear distribution. The $C\alpha$/Cc values of untreated soil, briquette ash treated soil and lime treated soil were approximately 0.049, 0.044 and 0.031, respectively. 4.The maximum consolidation coefficient was obtained with lime and briquette ash (lime : briquette .h 2 :1) mixture ratio of 15%. And the minimum secondary consolidation coefficient, compression index was obtained with same mixture ratio. The required quantity of lime could be reduced and the consolidation was accelerated by applying the above mixture ratio.

• 대기
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• 제29권4호
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• pp.439-450
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• 2019

Present weather plays an important role not only for atmospheric sciences but also for public welfare and road safety. While the widely used state-of-the-art visibility and present weather sensor yields present weather, a single type of measurement is far from perfect to replace long history of human-eye based observation. Truly automatic present weather observation enables us to increase spatial resolution by an order of magnitude with existing facilities in Korea. 8 years of human-eyed present weather records in 19 sites over Korea are compared with visibility sensors and auxiliary measurements, such as humidity of AWS. As clear condition agrees with high probability, next best categories follow fog, rain, snow, mist, haze and drizzle in comparison with human-eyed observation. Fog, mist and haze are often confused due to nature of machine sensing visibility. Such ambiguous weather conditions are improved with empirically induced criteria in combination with visibility and humidity. Differences between instrument manufacturers are also found indicating nonstandard present weather decision. Analysis shows manufacturer dependent present weather differences are induced by manufacturer's own algorithms, not by visibility measurement. Accuracies of present weather for haze, mist, and fog are all improved by 61.5%, 44.9%, and 26.9% respectively. The result shows that automatic present weather sensing is feasible for operational purpose with minimal human interactions if appropriate algorithm is applied. Further study is ongoing for impact of different sensing types between manufacturers for both visibility and present weather data.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1890-1896
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• 2006

Lumostatic operation for cultivation of Haematococcus pluvialis was assessed to test the scale-up strategy of photobioreactors. Lumostatic operation is a method of maintaining a proper light condition based on the specific light uptake rate ($q_e$), by cells. Lumostatic operations were performed in 0.4-, 2-, 10-, and 30-1 scale bubble column photobioreactors and the results were compared with cultures illuminated with constant light intensity. Significant differences were observed in the maximal cell concentrations obtained from 0.4-, 2-, 10-, and 30-1 scale photobioreactors under constant light intensity, yielding the maximal cell concentrations of $2.8{\times}10^5$, $2.2\times10^5$, $1.5\times10^5$, and $1.1\times10^5$ cells/ml, respectively. The maximal cell concentration in a 0.4-1 photobioreactor under lumostatic operation was $4.3\times10^5$ cells/ml. Furthermore, those in 2-, 10-, and 30-1 scale photobioreactors were about the same as that in the 0.4-1 photobioreactor. The results suggest that lumostatic operation with proper $q_e$ is a good strategy for increasing the cell growth of Haematococcus pluvialis compared with a constant supply of light energy. Therefore, lumostatic operation is not only an efficient way to achieve high cell density cultures with minimal power consumption in microalgal cultures but it is also a perfect parameter for the scale-up of photobioreactors.

• Journal of Microbiology and Biotechnology
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• 제8권6호
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• pp.650-655
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• 1998

The chromosomal DNA fragment from Phaffia rhodozyma CBS 6938 which is able to autonomously replicate in the yeast Saccharomyces cerevisiae was cloned on an integrative URA3 plasmid. Its minimal fragment exhibiting autonomously replicating activiy in the S. cerevisiae gave a higher frequency transformation efficiency than that found for centromere-based plasmid, and enabled extrachromosoma1ly stable transmission of the plasmids in one copy per yeast cell under non-selective culture condition. The 836-bp DNA element lacked an ORF and did not contain any acceptable match to an ARS core consensus. Sequence analysis, however, displayed a cluster of three hairpin-Ioop-sequences with individual $\triangle {G_{25}}^{\circ}C$ free energy value of -10.0, -17.5, and -17.0 kcal. $mor^{-l}$as well as a 9-bp sequence with two base pair mismatches to the S. cerevisiae/E. coli gyrase-binding site. This 836-bp sequence also included one 7-bp sequence analogous to the core consensus of centromeric DNA element III (CDEIII) of S. cerevisiae, but CDEIII-like 7 bp sequence alone did not give a replicative function in this yeast.

• 디자인학연구
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• 제15권4호
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• pp.369-378
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• 2002

가전제품 가운데 세탁기만큼 일손을 덜어주는 기계는 없다. 텔레비젼이나 식기세척기가 없어도 가정생활이 그렇게 불편하진 않겠지만 세탁기 없이 손빨래로 버틴다는 것은 상상하기 힘든 일이다. 그만큼 가전제품으로서 중요한 역할을 하는 세탁기의 형성과 디자인 발전을 살펴봄으로써 오늘날 가전제품의 발전과 진화를 이해하고자 하는 것이 이 연구의 배경이다. 먼저 세탁기는 노동절감기구들 중 대표적인 제품이란 점에 주목하여 그 기본형의 형성과 디자인 발전을 살펴보고 있다. 역사적 사례로서 세탁기가 앞서 개발되고 사용되어온 유럽과 미국을 중심으로 BO세기 세탁기의 형태 변화와 현재 정착된 세탁기를 분류하고, 거기서 발견되는 특성을 정리해보았다. 그리고 세탁기를 가사노동절약을 위한 하나의 인공물로써, 그것이 발전하는 가운데 디자인과 형태가 어떻게 진화되어왔으며, 그 과정에서는 어떠한 요소들의 영향이 있었는지 또한 분석하였다. 그리고 세탁기가 하나의 인공물로서 형성되고 진화되어 가는 과정을 한눈에 파악할 수 있는 자료를 제시하고 이를 통하여 이와 유사한 또 다른 인공물을 비교 연구하는데 있어 기준이 될만한 잣대를 제공하고자 하였다.

• 한국환경농학회지
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• 제29권2호
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• pp.176-183
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• 2010

Endosulfan degrading ability of Klebsiella oxytoca KE-8 immobilized by entrapment with activated carbon was examined. Endosulfan degradation by the immobilized bacterial strains on several different activated carbon based support materials was investigated. Based on results, activated carbon ($8\times30$ mesh) was chosen as a support material. The immobilized Klebsiella oxytoca KE-8 with the cell density of 4 mg $g^{-1}$ (dry weight) degraded 22.18 ug $ml^{-1}$ endosulfan within 5 days at pH 7.0, $30^{\circ}C$ in batch shake flask cultures. Also, we an experimented recycle packed bed column mode and continuous packed bed column mode for endosulfan degradation. Under optimum operation condition, the immobilized cells in a laboratory scale pack bed column with support beads were able to degrade endosulfan completely in defined minimal salt medium at a maximum rate of 129.6 ug $ml^{-1}$ per day. Moreover, the endosulfan degradation activity could be demonstrated at $4^{\circ}C$ for one month without significant decrease in activity. Results of this study suggest that immobilized cells of Klebsiella oxytoca KE-8 might be applicable to endosulfan contaminated site.

• Journal of Yeungnam Medical Science
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• 제30권2호
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• pp.136-140
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• 2013

Diabetic nephropathy (DN) is a common complication and the leading cause of end-stage renal disease (ESRD) in diabetic patients. The occurrence of non-diabetic renal disease (NDRD) in diabetic patients has been increasingly recognized in recent years. Generally, renal injuries in DN are deemed difficult to reverse, whereas some NDRDs are often treatable and even remittable. Thus, the diagnosis of NDRD in patients with diabetes mellitus (DM) via a kidney biopsy would be significant for its prognosis and therapeutic strategy. According to recent studies, the most common NDRD is IgA nephropathy in type 2 diabetic patients, and some cases of minimal change disease and membranous glomerulonephritis have been reported in Korea. However, membranoproliferative glomerulonephritis (MPGN) is an uncommon condition in diabetic patients. To our knowledge, there has been no case yet of MPGN, except in a child with type 1 DM. We present an unusual case of a 27-year-old woman who had type 2 DM with MPGN, as confirmed via a kidney biopsy.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.123-132
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• 2002

A numerical study was conducted to investigate the combustion phenomena of normal start and unstart processes based on ISL's RAMAC 30 experiments with different diluent amounts and fill pressures in a ram accelerator. The initial projectile launching speed was 1.8 km/s which corresponded to the superdetonative speed of the stoichiometric $H_2/O_2$ mixture diluted with 5 $CO_2$ or 4 $CO_2$. Experiments with same condition except for projectile surface material demonstrated that ignition was successful with an aluminum projectile, but no combustion was observed in case of a steel projectile. In this study, it was found that neither shock nor viscous heating was sufficient to ignite the mixture at a low speed of 1.8 km/s, as was found in the experiments using a steel projectile. However, we could succeed in igniting the mixtures by imposing a minimal amount of additional heat to the combustor section and simulate the normal start and unstart processes found in the experiments with an aluminum projectile. For the numerical simulation of supersonic combustion, multi-species Navier-Stokes equations coupled with a Baldwin-Lomax turbulence model and detailed chemistry reaction equations of $H_2/O_2/CO_2$ suitable for high-pressure gaseous combustion were considered. The governing equations were discretized by a high order accurate upwind scheme and solved in a fully coupled manner with a fully implicit, time accurate integration method. The numerical results matched almost exactly to the experimental results. As a result, it was found that the normal start and unstart processes depended on the strength of gas mixture, development of shock-induced combustion wave stabilized by the first separation bubble, and its size and location.