• 공업화학
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• 제9권6호
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• pp.884-888
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• 1998

고온 분위기하의 가열시간이 방사성물질의 수송용기 등에 사용하기 위하여 개발한 개질(KNS(Kaeri Neutron Shield)-102) 및 수소 첨가된 (KNS-106) 비스페놀-A형 에폭시수지계와 페놀-노블락형(KNS-611) 에폭시수지계 중성자 차폐재들의 열분해온도, 열전도도, 열팽창 등의 열적 성질 및 인장강도, 압축강도, 굴곡강도, 비중, 무게변화, 수소함량변화 등의 역학적 성질에 미치는 영향을 검토하였다. 고온 분위기하에서 가열시간이 증가함에 따라 초기단계에서 중성자 차폐재, KNS-102, KNS-106 및 KNS-611의 열분해온도는 증가하는 것으로 나타났으나, 초기단계 이후에는 거의 영향을 받지 않는 것으로 나타났다. 또한 가열시간의 증가에 따라 KNS-102와 KNS-106 차폐재의 열전도도는 감소하는 경향을 나타내었으나, KNS-611의 경우에는 증가하는 경향을 나타내었다. 반면 가열시간의 증가에 따라 중성자 차폐재들의 열팽창계수값은 모두 감소하였다. 고온 분위기하에서 가열시간의 증가에 따라 KNS-102와 KNS-611 차폐재의 인장강도 및 굴곡강도는 증가하는 경향을 나타내었으나, KNS-106은 감소하는 경향을 나타내었다. 그리고 고온 분위기하에서 가열시간은 중성자 차폐재들의 무게변화 및 수소함량의 변화에는 큰 영향을 미치지 않는 것으로 나타났다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.64-64
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• 2015

Control of plasma processing methodologies can only occur by obtaining a thorough understanding of the physical and chemical properties of plasmas. However, all plasma processes are currently used in the industry with an incomplete understanding of the coupled chemical and physical properties of the plasma involved. Thus, they are often 'non-predictive' and hence it is not possible to alter the manufacturing process without the risk of considerable product loss. Only a more comprehensive understanding of such processes will allow models of such plasmas to be constructed that in turn can be used to design the next generation of plasma reactors. Developing such models and gaining a detailed understanding of the physical and chemical mechanisms within plasma systems is intricately linked to our knowledge of the key interactions within the plasma and thus the status of the database for characterizing electron, ion and photon interactions with those atomic and molecular species within the plasma and knowledge of both the cross-sections and reaction rates for such collisions, both in the gaseous phase and on the surfaces of the plasma reactor. The compilation of databases required for understanding most plasmas remains inadequate. The spectroscopic database required for monitoring both technological and fusion plasmas and thence deriving fundamental quantities such as chemical composition, neutral, electron and ion temperatures is incomplete with several gaps in our knowledge of many molecular spectra, particularly for radicals and excited (vibrational and electronic) species. However, the compilation of fundamental atomic and molecular data required for such plasma databases is rarely a coherent, planned research program, instead it is a parasitic process. The plasma community is a rapacious user of atomic and molecular data but is increasingly faced with a deficit of data necessary to both interpret observations and build models that can be used to develop the next-generation plasma tools that will continue the scientific and technological progress of the late 20th and early 21st century. It is therefore necessary to both compile and curate the A&M data we do have and thence identify missing data needed by the plasma community (and other user communities). Such data may then be acquired using a mixture of benchmarking experiments and theoretical formalisms. However, equally important is the need for the scientific/technological community to recognize the need to support the value of such databases and the underlying fundamental A&M that populates them. This must be conveyed to funders who are currently attracted to more apparent high-profile projects.

• 대한전자공학회논문지SD
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• 제38권5호
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• pp.329-337
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• 2001

고유전 (Ba, Sr)TiO/sub 3/ (BST) 박막을 이용한 DRAM storage capacitor의 저전계 영역에서의 전하손실을 발생시키는 커패시터의 누설전류는 유전완화전류와 진성 누설전류로 이루진다고 알려져 있다. 특히, 기가급 DRAM의 동작 전압(~IV)에서 유전완화전류가 진성 누설전류에 비해 훨씬 크기 때문에 이에 대한 심도 있는 연구가 필요하다. 본 연구에서는 thermally stimulated current (TSC) 측정법을 BST 박막에 처음으로 적용하여 트랩의 에너지 level 및 공정변화에 따른 트랩 밀도의 상대적 평가를 하였다. 그리고, 기존에 사용되던 전류-전압(I-V) 측정이나 전류-시간(I-t) 측정과 비교 및 분석함으로써 유전완화 전류의 원인을 규명하고 TSC 측정법의 신뢰성을 살펴보았다. 먼저 안정적인 TSC 측정을 위해 전계, 시간, 온도 및 승온속도에 따른 polarization condition을 알아보았다 이 조건을 이용한 TSC 측정으로부터 BST 박막에서의 트랩의 energy level이 0.20(±0.01) eV와 0.45(±0.02) eV임을 알 수 있었다. Rapid thermal annealing (RTA)을 이용한 후속 열처리에 따른 TSC 측정을 통하여 이 트랩들이 산소결핍(oxygen vacancy)에 기인함을 확인할 수 있었다. MIM BST 커패시터의 열처리에 대한 TSC 특성은 전류-전압(I-V) 및 전류-시간(I-t) 특성과 같은 경향성을 보인다. 이것은 TSC 측정이 BST 박막내의 트랩을 평가하는데 있어서 매우 효과적인 방법이라는 것을 보여준다.

• 한국임상약학회지
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• 제23권4호
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• pp.307-315
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• 2013

Objective: Colistimethate was first became available in 1950s and used until the early 1980s to treat infections caused by gram-negative bacteria and was abandoned due to its nephrotoxicity and neurotoxicity. However, it was recently reintroduced into the clinical practices due to emergence of multidrug-resistance gram-negative bacteria, particularly Pseudomonas aeruginosa and Acinetobacter baumanii. Therefore, it is increasingly used in the intensive care unit settings as a salvage therapy. This study was designed to investigate the incidence rates and risk factors of acute kidney injury associated with colistimethate by using the standardized definition in critically ill patients. Methods: This study retrospectively reviewed the electronic medical records of 71 adult patients above 18 years old receiving intravenous colistimethate at least 48 hours at intensive care unit, university-affiliated hospital from Nov 2012 to Aug 2013 and excluded patients with end-stage renal disease (ESRD) and required renal replacement therapy before initiation of the colistimethate therapy. Acute kidney injury (AKI) was determined by using the standardized RIFLE criteria, classified with risk, injury, failure, loss and ESRD according to serum creatinine (Scr) levels. Results: Among the 71 patients included in the analysis, AKI developed in 40 patients (56.3%) and 6 patients (8.4%) had irreversible kidney injury. AKI occurred within 5 days in 20 patients (50.0%). Maximum Scr level showed a significant increase in the patients with AKI ($1.92{\pm}0.86mg/dL$ vs. $1.12{\pm}0.46mg/dL$ p=0.001), maximum BUN also increased ($64.2{\pm}28.7mg/dL$ vs. $48.4{\pm}24.9mg/dL$ p=0.017) and minimum creatinine clearance (CLcr) was significantly decreased in the patients with AKI than non-AKI ($34.5{\pm}18.6ml/min$ vs. $64.4{\pm}33.7ml/min$ p=0.185). The patients with AKI had significantly longer duration of colistimethate therapy ($21.1{\pm}17.0$ days vs. $13.0{\pm}11.5$ days, p=0.020) and larger cumulative doses of colistimethate ($6465.9{\pm}4717.0mg$ vs. $4438.1{\pm}3426.7mg$, p=0.040). Conclusion: The incidence and severity of AKI associated with colistimethate in critically ill patients was high and serious. Drug monitoring program should be performed to shorten duration of therapy and reduce cumulative dose from initiation of colistimethate therapy for minimizing AKI of colistimethate.

• Journal of Gastric Cancer
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• 제17권1호
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• pp.33-42
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• 2017

Purpose: Endoscopic submucosal dissection (ESD) in early gastric cancer causes an artificial gastric ulcer and local inflammation that has a negative intraprocedural impact on additional laparoscopic gastrectomy in patients with noncurative ESD. In this study, we analyzed the effect of ESD on short-term surgical outcomes and evaluated the risk factors. Materials and Methods: From January 2003 to January 2013, 1,704 patients of the National Cancer Center underwent laparoscopic gastrectomy with lymph node dissection because of preoperative stage Ia or Ib gastric cancer. They were divided into 2 groups: (1) with preoperative ESD or (2) without preoperative ESD. Clinicopathologic factors and short-term surgical outcomes were retrospectively evaluated along with risk factors such as preoperative ESD. Results: Several characteristics differed between patients who underwent ESD-surgery (n=199) or surgery alone (n=1,505). The mean interval from the ESD procedure to the operation was 43.03 days. Estimated blood loss, open conversion rate, mean operation time, and length of hospital stay were not different between the 2 groups. Postoperative complications occurred in 23 patients (11.56%) in the ESD-surgery group and in 189 patients (12.56%) in the surgery-only group, and 3 deaths occurred among patients with complications (1 patient [ESD-surgery group] vs. 2 patients [surgery-only group]; P=0.688). A history of ESD was not significantly associated with postoperative complications (P=0.688). Multivariate analysis showed that male sex (P=0.008) and laparoscopic total or proximal gastrectomy (P=0.000) were independently associated with postoperative complications. Conclusions: ESD did not affect short-term surgical outcomes during and after an additional laparoscopic gastrectomy.

• 한국건설순환자원학회논문집
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• 제7권4호
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• pp.95-103
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• 2012

프리캐스트 콘크리트 공법은 건식공법으로서 현장에서의 작업량을 최소화할 수 있으며 품질관리가 쉽고, 조립으로 공기단축이 가능하지만, 공기상 조기에 콘크리트 강도를 확보하기 위하여 콘크리트의 강도발현속도를 촉진시키는 증기양생법에 의존하여 왔다. 그러나 최근에 나타나고 있는 중동에서의 정치적 불안이나 국제 경제의 불안정으로 인해 지속적으로 유류비는 상승되고 있다. 따라서 본 연구에서는 프리스트레스트용 프리캐스트 콘크리트 제품 생산을 위해 저온의 조건에서 증기양생을 사용하지 않고 1일 압축강도 14MPa 이상, 설계기준압축강도 40MPa를 확보하는 콘크리트 개발을 목표로 하였다. 1종 포틀랜드시멘트와 3종 조강포틀랜드시멘트, 특수목적의 조강혼합시멘트 등 3종류의 시멘트에 대해 굳지 않은 콘크리트의 물성과 압축강도를 실험을 통해 평가하였다. 실험결과, 조강용 시멘트들은 슬럼프와 슬럼프경시변화, 공기량 확보 측면에서 불리하였지만 강도 측면에서는 목표값 이상을 확보하였으며 특히, 조강혼합시멘트가 가장 우수한 것으로 나타났다.

• 한국건설순환자원학회논문집
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• 제8권1호
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• pp.33-40
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• 2013

최근 시멘트 생산 시에 발생하는 다량의 $CO_2$로 인한 환경문제가 심각한 실정이며, 이러한 환경문제를 해결하기 위해 고로슬래그 미분말과 같은 산업부산물을 시멘트 대체 재료로 사용한 알칼리 활성 슬래그 콘크리트에 대한 연구가 활발히 진행되고 있다. AAS 콘크리트는 상온에서 고강도 발현이 가능하지만 알칼리 반응으로 인한 빠른 응결시간과 유동성 손실로 인해 작업시간 확보에 어려움이 있는 것으로 알려져 있다. 본 연구에서는 알칼리 활성 콘크리트의 구조 부재 적용을 위한 기초 자료 확보를 위해 AAS 모르타르의 압축강도 및 유동 특성에 시멘트용 유동화제가 미치는 영향을 분석하였다. 물-결합재비(W/B)는 0.35로 고정하고 알칼리 활성화제로 수산화나트륨과 물유리를 사용하여 AAS 모르타르를 제조하였으며, 유동성 확보를 위해 4종의 유동화제인 나프탈렌(N), 리그닌(L), 멜라민(M), PC(P) 계를 각각 슬래그 질량대비 최대 2%까지 첨가하여 압축강도, 플로우, 초음파 속도를 측정하였다. 실험결과, 멜라민계 유동화제를 첨가한 경우 AAS 모르타르의 압축 강도 저하 현상 없이 유동성이 증진되는 것으로 나타났으며, 나프탈렌계와 PC계의 경우에는 유동성 개선효과가 미미한 것으로 나타났다.

• Molecules and Cells
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• 제43권10호
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• pp.889-897
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• 2020

K-RAS is frequently mutated in human lung adenocarcinomas (ADCs), and the p53 pathway plays a central role in cellular defense against oncogenic K-RAS mutation. However, in mouse lung cancer models, oncogenic K-Ras mutation alone can induce ADCs without p53 mutation, and loss of p53 does not have a significant impact on early K-Ras-induced lung tumorigenesis. These results raise the question of how K-Ras-activated cells evade oncogene surveillance mechanisms and develop into lung ADCs. RUNX3 plays a key role at the restriction (R)-point, which governs multiple tumor suppressor pathways including the p14^ARF-p53 pathway. In this study, we found that K-Ras activation in a very limited number of cells, alone or in combination with p53 inactivation, failed to induce any pathologic lesions for up to 1 year. By contrast, when Runx3 was inactivated and K-Ras was activated by the same targeting method, lung ADCs and other tumors were rapidly induced. In a urethane-induced mouse lung tumor model that recapitulates the features of K-RAS-driven human lung tumors, Runx3 was inactivated in both adenomas (ADs) and ADCs, whereas K-Ras was activated only in ADCs. Together, these results demonstrate that the R-point-associated oncogene surveillance mechanism is abrogated by Runx3 inactivation in AD cells and these cells cannot defend against K-Ras activation, resulting in the transition from AD to ADC. Therefore, K-Ras-activated lung epithelial cells do not evade oncogene surveillance mechanisms; instead, they are selected if they occur in AD cells in which Runx3 has been inactivated.

• 한국식품과학회지
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• 제2권1호
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• pp.81-87
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• 1970

사과 국광(國光)에 $5{\sim}100$ krad의 ${\gamma}$선(線)을 조사(照射)하고 저장중( 貯藏中) 품질(品質)과 화학성분(化學性分)에 미치는 ${\gamma}$선(線)의 영향(影響)과 polyethylene film 포장(包裝)의 병용효과(倂用效果)를 검토(檢討)하고 다음과 같이 그 결과(結果)를 보고(報告)한다.1. 사과 국광(國光)에 대(對)한 $50{\sim}100krad$의 ${\gamma}$선(線) 처리(處理)는 저장중 부패(貯藏中 腐敗) 및 생리장해(生理障害)의 발생(發生)을 억제(抑制)할 수 있었다. 2. 사과 국광(國光)에 대(對)한 ${\gamma}$선(線) 처리(處理)는 저장초기(貯藏初期)에 위축현상(萎縮現象)을 증가(增加)시켰다. 3. 그러나 ${\gamma}$선(線) 조사(照射)에 의(依)한 위축현상(萎縮現象)의 증가(增加)는 Polyethylene film 포장(包裝)을 병용(倂用)함으로써 억제(抑制)가 가능하였다. 4. ${\gamma}$선(線)조사구(照射區)와 Polyethylene film 포장구(包裝區)에서 중량감소률(重量減少率)이 낮았다. 5. 저장중 당함량(貯藏中 糖含量)의 포장(包裝)에 미치는 ${\gamma}$선조사(線照射) 및 polyethylene film 변화(變化)의 영향은 근소하였다.

• 대한후두음성언어의학회지
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• 제15권2호
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• pp.128-132
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• 2004

Objectives : The total laryngectomy for laryngeal cancer has made patients be afraid of voice loss. Early staged glottic or supraglottic cancer can be treated with conservative laryngeal surgery which preserve voice, though which was not normal voice comparing before. Voice analysis is used to evaluates objectively the quality of the voice in pre- and postoperation, 4 different types of conservative laryngeal surgery : laser cordectomy, supracticoid partial laryngectomy, vertical partial laryngectomy, and supralottic laryngectomy. Materials and Methods : The patients who received conservative laryngeal surgery(laser cordectomy : 23 cases, vertical partial laryngecotmy : 9cases, supracriocoid partial laryngectomy : 6cases, supraglottic laryngectomy : 8cases) from 1995 to 2001 in the Asan medical center. Fundamental frequency(F0), shimmer, jitter, noise to harmony ratio(NHR), maximum comfortable phonation time and subglottic pressure were used as parameters for voice analysis. Results : The patients who received laser cordectomy(shimmer : 5.26${\pm}$1.12%, jitter : 3.33${\pm}$0.42%, NHR : 0.47${\pm}$0.02, MPT : 9.32${\pm}$3.59sec) and supraglottic laryngectomy(shimmer : 4.39${\pm}$1.03%, jitter : 1.49${\pm}$0.14%, NHR : 0.51${\pm}$0.06, MPT : 8.9${\pm}$0.59sec) showed better results than other two procedures, but differed from normal value. Especially the patients who received supracricoid partial laryngectomy(shimmer : 9.23${\pm}$1.56%, jitter : 5.81${\pm}$1.23%, NHR : 5.89${\pm}$1.13, MPT : 6.3${\pm}$1.18sec, MFR : 632${\pm}$89ml/sec) had poorer quality of voice but presented fast functional recovery time, and the subjective symptom was improved as time goes by slowly. Conclusion : The appropriate conservative laryngeal surgery for each cancers and stage can preserve the acceptable voice for patients. Supracricoid partial laryngectomy for T1b glottic cancer can be used for acceptable voice despite its poor voice analysis.