• Nuclear Engineering and Technology
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• 제55권3호
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• pp.902-907
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• 2023

To understand the eutectic reaction mechanism and the relocation behavior of the core debris is indispensable for the safety assessment of core disruptive accidents (CDAs) in sodium-cooled fast reactors (SFRs). This paper addresses reaction products and their distribution of the eutectic melting/solidifying reaction of boron carbide (B₄C) and stainless-steel (SS). The influence of the existence of carbon on the B₄C-SS eutectic reaction was investigated by comparing the iron boride (FeB)-SS reaction by Raman spectroscopy with Multivariate Curve Resolution (MCR) analysis. The scanning electron microscopy with dispersive X-ray spectrometer was also used to investigate the elemental information of the pure metals such as Cr, Ni, and Fe. In the B₄C-SS samples, a new layer was formed between B₄C/SS interface, and the layer was confirmed that the formed layer corresponded to amorphous carbon (graphite) or FeB or Fe₂B. In contrast, a new layer was not clearly formed between FeB and SS interface in the FeB-SS samples. All samples observed the Cr-rich domain and Fe and Ni-rich domain after the reaction. These domains might be formed during the solidifying process.

• Radiation Oncology Journal
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• 제23권1호
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• pp.51-60
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• 2005

목적 : 분자 표적의 선택적 억제가 방사선 세포 살상 효과를 증진시키는 것으로 알려져 있으므로 선택적 COX-2 억제제와 EGF 수용체 차단제를 HeLa 세포주에 처리한 후 방사선 효과의 상승작용을 알아보고자 하였다. 대상 및 방법 : 자궁경부암 세포주인 HeLa세포에서 EGF 수용체 차단제 AG 1478, 선택적 COX-2 억제제 NS 398과 방사선을 복합 투여하여 세포성장 억제 분석(cell graph inhibition assay)과 세포사멸 분석(apoptosis assay)을 시행하였고, 방사선 감수성 변화를 살펴보기 위해 세포생존 분석(clonogenic survival assay)을 시행하였다. 방사선 감수성 인자로는 2 Gy에서의 세포생존분획($SF_2$)과 linear-quadratic model을 이용한 dose enhancement ratio (DER)를 사용하였다. 방사선 감수성에 대한 작용기전 분석을 위해 flow cytometry로 세포주기 분석(cell cycle analysls)을 시행하였고, western blot 분석을 통하여 bcl-2와 bax 단백질의 발현 변화를 살펴보았다. 결과 : HeLa세포에 NS 398과 AG 1478을 방사선과 함께 복합 투여한 실험 군에서 세포사멸 정도가 가장 높게 나타났다($8.49\%$ vs. $22.70\%$). 세포주기 분석 결과, 방사선과 복합 약물 처리군에서 $G_0/G_l$ 세포주기 정체와 5 세포 분획 소실이 나타났으며 이러한 변화는 72시간 이후까지 지속되었다 세포생존 분석 결과로는 방사선과 AG 1478군에서 $SF_{2}0.68{\pm}0.07$, DER 1.12를 보인 반면, 방사선과 복합약물처리군에서는 $SF_{2}0.12{\pm}0.01,\;DER\;3.00$으로 나타났다. Western blot분석에서는 방사선과 복합약물처리군에서 bcl-2와 bax 단백질 발현이 모두 감소하는 양상을 보였다. 결론 : 신호전달 체계를 억제하는 분자 표적 약제인 선택적 COX-2 억제제와 EGF 수용체 차단제를 방사선과 복합투여함으로써 HeLa세포의 방사선 감수성이 증가됨을 확인하였다.

• 한국주조공학회지
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• 제42권5호
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• pp.273-281
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• 2022

Al-Cu-Si 3원계 공정합금의 응고거동과 미세조직 변화를 이해하기 위해서, 금형 예열온도를 달리하여 Al-Cu-Si 3원계 공정합금의 미세조직 변화를 관찰하였다. 금형 예열온도가 500℃일 때, 초정 Si과 덴드라이트 형상의 Al2Cu상이 관찰되며, 이후 (α-Al+Al2Cu)의 2원계 공정상이 관찰된다. 금형 예열온도가 300℃일 때 미제조직은 금형 예열온도가 500℃일 때와 유사하나 (α-Al+Al2Cu+Si)의 3원계 공정상이 관찰되는 영역과 관찰되지 않는 영역이 나타난다. 금형 예열온도가 150℃인 경우에는 미세조직이 (α-Al+Al2Cu)의 2원계 공정상과 (α-Al+Al2Cu+Si)의 3원계 공정상이 관찰되는 Bimodal 구조를 나타낸다. 금형 예열온도를 달리 하였을 때 가장 큰 변화를 나타내는 상은 Si상이며, 임계냉각속도를 지나면 (α-Al+Al2Cu+Si)의 3원계 공정상이 형성되는 순간에 빠른 냉각에 의한 Si의 성장이 억제되면 Cooperative 성장을 하기 때문에 Al, Cu의 성장도 함께 억제된다. 서로 다른 합금설계 전산모사 프로그램을 통해 Al-27wt%Cu-5wt%Si의 3원계 공정 합금을 분석한 결과, 합금설계 전산모사 프로그램에 따라 결과의 차이가 발생하며, 전산모사의 신뢰성을 높이기 위해서는 실제 주조를 통한 미세조직 분석이 수반되어야 한다.

• 폴리머
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• 제25권5호
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• pp.736-743
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• 2001

N,N-Methylenebisacrylamide (MBAA)로 가교 결합된 electro-active 고분자(EAP) (poly(2-acrylamido-2-methylpropane sulfonic acid), PAMPS) 겔을 수용액 상에서 potassium persulfate를 개시제로 하여 라디칼 중합시켜 제조하였다. PAMPS 겔의 구동성을 부여하기 위하여 계면활성제로 팽윤하며 치환하였다. 계면활성제가 치환된 PAMPS 겔은 용액내의 인가된 전압하에서, 그 전기장 변화에 의해 큰 변위를 나타내는 구동특성을 보였다. PAMPS 겔은 빠른 응답속도와 가역적인 bending을 나타내었다. 겔의 구동원리는 양극과 PAMPS 겔 음이온간의 정전기 인력, 겔의 swelling-deswelling 효과 그리고 계면활성제의 소수성 반응의 협동적 과정으로 나타난다. PAMPS 겔의 응답속도는 인가된 전압 및 가교도가 증가할수록 증가하였으며, 구동이 반복적으로 진행됨에 따라 응답속도는 증가하였다. 겔의 두께가 증가하면 응답속도는 감소하였다.

• 펄프종이기술
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• 제31권5호
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• pp.1-11
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• 1999

Wood components, cellulose and lignin, are degraded simultaneously and the general outline for the complementary character of carbohydrates and lignin decomposition as well as the existence of enzymatic systems combining these processes is still valid. The degradatiion of free cellulose or hemicellulose into monosaccharides has long been known to be relatively simple, but the mechanism of lignin degradatiion wasn ot solved very clearly yet. Anyway the biodegradation of woold constituents is understood at present as an enzymatic process. Kigninolytic activity has been correlated with lignin and manganese peroxidases. At present the attention is paid to laccase. Laccase oxidizes lignin molecule to phenoxy radicals and quinones . This oxidation can lead to the cleavageo f C-C or C-O bonds in the lignin phenyl-propane subunits, resulting either in degradation of both side chains and aromatic rings, or in demethylation processes. The role of laccase lies in the "activation" of some low molecular weight mediators and radicals produced by fungal cultures. Such activated factors produced also in cooperation with other enzymes are probably exported to the wood environment where they work in degradation processes as the ' enzyme messengers." It is worth mentioning that only fungi possessing laccase show demethylating activity. Thus demethylation, the process important for ligninolysis, is probably caused exclusively by laccase. Under natural conditions laccase seems to work with other fungal enzymes , mediators and mediating radicals. It has shown the possibility of direct Bjrkman lignin depolymerization by cooperative activity of laccase and glucose oxidase.

• 대한한의학방제학회지
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• 제13권1호
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• pp.9-33
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• 2005

Acetaminophen, which causes acute liver min in humans and animals, has made useful inducer of hepatoxicity for studying hepatopreventive drugs. Injinhotang is known as one of the hepatopreventive drugs. However, its mechanism of recovery of hepatoxicity treated with acetaminophen is poorly understood. this study was performed to observe the antioxidative effect of injinhotang extract and its several combination groups. The results were obtained as follows:1. In the study on free radical scavenging effect in vitro(the suppressing effect on peroxidation of linoleic acid on concentration, the scavenging effect of DPPH radical, inhibitory effect of superoxide in xanthine-xanthine oxidase system and the inhibitory effect on lipid peroxidation reaction by hydroxy radical in H2O2-Fe2+system, injinhotang have more effect than its components groups relatively. 2. In the study on antioxidants system in vivo(the level of serum LPO, the level of hepatic LPO, catalase, GSH, GST), only injnhotang has a significant effect. 3. In the study on hepatotoxicity(GOT, GPT, $\gamma$-GTP, ALP, LDH, b ilirubin), only injinhotang has a significant effect. These results suggest that injinhotang has the protective effect on acetaminophen-induced hepatoxicity. The mechanisms of these are supposed to be involved in antioxidant and three drugs' cooperative synergy effect.

• 한국중재학회지:중재연구
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• 제16권2호
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• pp.3-49
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• 2006

The purpose of this paper is to make research on the settlement mechanism of the commercial disputes between the South and the North of Korea. Also, this paper is to make research on the south-north Korea's cooperative tasks to promote the disputes settlement, including the operation and management of the South-North Arbitration Commission as well as the enactment of the South-North Arbitration Rules. To realize the spirit of the South-North Joint Declaration of June 15, 2000, the Authorities concerned of the South and the North of Korea have reached an agreement titled 'Agreement on Settlement Procedure of Commercial Disputes' on December of the same year. As the follow-up measures of the said Agreement, the South-North Authorities have signed an another agreement called 'Agreement on Organization and Administration of the South-North Arbitration Commission' on October, 2003, which is becoming vital importance for settlement of the commercial disputes between south and north Korea including the Gaeseong Industrial Complex. Gaeseong, a city surrounded by the North Korean military and a symbol of inter-Korean tensions, is now turning into a peace zone where thousands of North and South Koreans are working side by side. The Gaeseong Industrial Complex project, driven by the logic and economic necessity of cooperation, has been steadily moving forward since the North designated it as a special economic zone and has enacted related laws and regulations for its development. Under the situation, the matter of primary concern is how to organize and conduct the Arbitration Commission for the prompt and effective settlement of the south-north commercial disputes. First of all, the South-North Authorities should recognize that the availability of prompt, effective and economical means of dispute resolution such as arbitration and mediation to be made by the Arbitration Commission would promote the orderly growth and encouragement of the south-north trade and investment. In this connection, the Korean Commercial Arbitration Board(KCAB) should be designated as the arbitral institution of the south Korean side under the Agreement on Organization and Administration of the South-North Arbitration Commission. The KCAB is the only authorized arbitral organization in South Korea to settle all kinds of commercial disputes at home and abroad.

• 한국지반환경공학회 논문집
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• 제19권9호
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• pp.29-36
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• 2018

국내 외에서는 사면붕괴를 사전에 예방할 수 있는 모니터링 및 자동계측기에 관한 다수의 연구가 수행되어져 오고 있으나, 이러한 연구들은 다소 복잡한 구조로 이루어져 있고, 계측시스템의 대부분은 사면표층에 설치되어 있으며, 사면파괴 전 붕괴징후를 사전에 감지하고 경보를 울려주는 계측시스템에 관한 연구는 미진한 실정이다. 본 연구에서는 강우 조건에서의 사면 붕괴 메카니즘을 파악하기 위하여 사면 붕괴 실험을 수행하고 지중 변위와 체적 함수비 계측을 통해 사면 모델의 붕괴 초기에 발생되는 함수비와 변위 거동 특성을 분석하였다. 본 연구를 통해 고찰된 내용은 지방자치단체에서 집중호우로 인해 급경사지 붕괴위험지역 등 사면붕괴나 산사태가 예측될 때 사전에 주민을 대피시키는 사면붕괴 예 경보시스템 구축 시 기초자료로 활용될 수 있을 것으로 기대된다.

• Korean Journal of Acupuncture
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• 제34권2호
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• pp.88-99
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• 2017

Objectives : Saam acupuncture initiated by Saamdoin in $17^{th}$ century is one of the most widely adopted acupuncture techniques used by Korean medical doctors in clinic. Our study aimed to analyze the application of the Saam acupuncture method to pain diseases based on the literature data. Methods : Based on the contents described in "(Do Hae Kyo Kam) Saam's acupuncture method", the texts related to pain condition were analyzed. The frequency of prescription of Saam acupuncture method was analyzed, and then the relationships between each acupoint were visualized by network analysis and hierarchical cluster analysis for the quantitative aspect. Results and conclusions: In our study, Lung tonifying and Liver tonifying acupuncture were the most frequently used method for the treatment of pain disease. As the acupoints, BL66 and SI5 were used the most frequently. It was found that visceral pattern identification was considered as the most important factor in the selection of the Saam acupuncture method. Network analysis and hierarchical clustering analysis showed that each acupoint was closely related to other acupoints, and most of them were connected more closely according to the method of Saam acupuncture operation. The experiential prescriptions of Saam acupuncture were classified as an independent group. In the future, fundamental research on the principle of Saam acupuncture method is needed for the various diseases, and research for the clinical efficacy and the mechanism of Saam acupuncture method should be preceded.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 춘계학술대회
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• pp.78-78
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• 1995

Increasing evidence indicates that the production of nitric oxide (NO) by inducible NO synthase (NOS) is tightely regulated. Transforming growth factor-${\beta}$ (TGF-${\beta}$) is a homodimeric protein secreted during macrophage activation, but several lines of evidence suggest that TGF-${\beta}$ is selectively suppressive for macrophage NO production. We therefore reasoned that a strategy employing oligodeoxynucleotides(ODNs) complemently to TGF-${\beta}$ mRNA (antisense ODNs) might increase NO production in IFN-${\gamma}$-treated murine peritoneal macrophages. To evaluate this concept, we tested the effects of antisense ODNs targeted to TGF-${\beta}$ mRNA (25-mer ODNs complemently to TGF-${\beta}$mRNA sequences) by introducing it into the medium of cultured macrophages. Phosphorothiolation of ODNs were employed to retard their degradation. Antisense ODNs had no effect on NO production by itself, whereas IFN-${\gamma}$ alone had modest effect. When antisense ODNs were used in combination with IFN-${\gamma}$, there was a marked cooperative induction of NO production, These effects of antisense ODNs were associated with decreased TGF-${\beta}$ expression in activated macrophages. ODNs with the same nucleotides but a scrambled sequence had no effect. Adding anti-TGF-${\beta}$ antibodies to the IFN-${\gamma}$-treated macrophages mimicked the positive effect of antisense ODNs on NO production. In addition, the effects of either antisense ODNs or anti-TGF-${\beta}$ antibodies were blocked by adding TGF-${\beta}$ in cultured macrophages. These results indicate that the generation of TGF-${\beta}$ by activated macrophages provides a self-regulating mechanism by which the temporal and perhaps spatial production of NO, a reactive and potentially toxic mediator, can be finely regulated.