Because of the International Maritime Organization(IMO)'s regulation to regulate emissions of ships, a change is taking place to replace ship fuels from Heavy Fule Oil(HFO) to Liquefied Natural Gas(LNG). In the case of LNG, it is a material obtained by liquefying Natural Gas(NG), and it is -163 degrees below zero, and the volume is reduced to 1/600 level. The material of the tank that can store LNG must be a material that can safely store LNG in a cryogenic environment, and the materials of the tank that can store LNG are limited in the International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk(IGC Code). Among the materials listed in the IGC Code, 9% nickel steel is used as a material for LNG fuel propulsion tanks that are recently ordered because of relatively high mechanical properties under cryogenic environments. In this study, the mechanical properties of butt welds were measured following the weld reliability evaluation of Flux Cored Arc Welding(FCAW) butt welds made of 9% nickel steel by PARTI. The measured mechanical properties are tensile strength, bending strength, hardness, and cryogenic impact test required by the classification for Welding Procedure Specification(WPS) approval.

When performing finite element analysis using materials with porosity the porosity shows different mechanical properties from the existing mechanical properties of the existing base materials. In this study the equivalent properties were calculated and verified by applying the representative volume element (RVE) method and assuming that the material with porosity is a 2D orthotropic material. In case of finite element analysis using porous material or composite material, it is inefficient to perform the analysis through material modeling. Based on the element volume and element stress values ​​derived using the finite element analysis program, the representative stress values ​​and elastic modulus matrix were calculated using Python. In addition, equivalent properties were derived using the calculated elastic modulus matrix. The pores were simulated by etching a thin plate specimen made of STS304 material in a certain pattern, and the elastic modulus and Poisson's ratio were measured through a UTM and compared with simulation results. It was confirmed that an error of 7.028% for elastic modulus and 10% for Poisson's ratio occurred, and through this, the validity of this simulation was verified.

육상풍력의 보급이 지연되는 가장 큰 원인인 입지애로 문제를 해결하기 위해 육상풍력 사업성 사전 검토 단계에서 입지적 합성을 검토할 수 있도록 육상풍력 입지지도가 개발되었다. 본 연구에서는 육상풍력 입지지도 고도화의 일환으로 산업부, 환경부, 산 림청의 부처간 협의에 따라 풍력자원, 생태·환경 입지요인 24종, 산림 입지요인 21종을 통합하여 육상풍력 입지 적합성을 종합적으로 평가할 수 있는 고려대상 지역 지도를 개발하였다. 고려대상 지역 지도를 분석한 결과 환경·산림 입지 적합성이 모두 상(high)이고 경제성이 확보되는 지역은 조사대상 면적의 4%인 4,032km2로 산정되었으며, 고려대상 지역의 민감도 분석에 의하면 생태·자연도 1등급 및 2등급과 겨울철 조류동시센서스 조사지역의 민감도가 가장 큰 것으로 확인하였다. 이를 통해 육상풍력 입지의 사전 검토를 위한 고려대상 지역 지도의 실효성을 확인하였다.

이 연구는 노화된 흰쥐를 대상으로 규칙적인 저항성 운동에 유산소 운동을 병행하는 훈련을 실시하여 골격근에서 나타나는 혈관신생 관련 단백질 발현의 반응을 관찰하기 위해 수행되었다. 연구의 목적을 위해 자연적으로 노화된 SD계열 흰쥐(20-24개월령, N=18)를 사용하여 통제(CON, n=6), 저항성 운동 (RE, n=6), 저항성+유산소 운동(RE+AE, n=6) 집단으로 구분하였다. 저항성 운동 집단은 실험동물용 사다리를 이용하여 매회 3세트×4회의 운동을 실시하였고 저항성 운동+유산소 운동 집단은 매회 2세트×3회의 사다리 오르기와 추가적인 30분간의 트레드밀 달리기를 수행하였다. 총 8주간의 운동 훈련 종료 후 가자미 근과 장지신근을 적출하여 분석에 사용하였다. 골격근에서 혈관신생 관련 단백질들(HIF-1α, VEGF, FLK-1, Ang-1, Ang-2)의 발현 수준을 분석하기 위해 western blot을 실시하였다. 연구결과, 저항성+유산소 운동 집단에서 가자미근(type I 근육)의 HIF-1α, VEGF, FLK-1, Ang-1, Ang-2 단백질 발현이 통제 집단에 비해 높았으며 저항성 운동만 수행할 경우 HIF-1α, VEGF, Ang-1, Ang-2 단백질 발현이 통제 집단에 비해 높았다. 또한 가자미근에서 저항성+유산소 운동훈련 집단의 Ang-2 to Ang-1 ratio가 저항성 운동 집단에 비해 높아 운동훈련 유형별 차이를 보였다. 한편, 장지신근(type II 근육)에서 HIF-1α는 저항성 운동 훈련에 의해서만 증가된 반면 VEGF와 FLK-1 단백질 발현은 두 훈련 유형 모두에서 증가되었고 운동 훈련 유형별 차이는 관찰되지 않았다. 또한 장지신근의 angiopoieitin 단백질들의 발현은 운동 훈련에 의한 차이가 없었다. 그러므로 노화에서 규칙적인 운동 훈련은 운동 유형에 관계없이 골격근 혈관신생 반응을 유도하며, 특히 저항성 운동에 유산소 운동의 병행은 type I 근조직 유형에서 혈관신생에 대한 추가적인 긍정적 효과를 가질 수 있다.

Nitrogen-doped carbon dots (CDts) with tunable fluorescence properties in aqueous media were synthesized hydrothermally. The excitation wavelength variation to obtain the maximum emission produced a blue shift in the emission peaks upon dilution in an aqueous solution. The shift can be explained by a re-absorption phenomenon in a concentrated solution. The interparticle interaction within was responsible to show dilution-dependent optical behavior. The as-synthesized solution of CDts did not show any prominent absorption peak over a wide range. However, upon dilution, two peaks became predominant. The concentration-dependent behavior was observed during the interaction with metal cations. Cationic salts of Co(II) and Hg(II) caused quenching at different dilutions of CDts. This might be explained by the exposure of different surface functional groups during dilution and metal-ion–CDts charge transfer. The quenched fluorescence of CDts was rescued using ascorbic acid. Therefore, the one-pot detection of Co(II)/Hg(II) and ascorbic acid was designed through a ‘Turn Off/On’ phenomenon.

The purpose of this study was to remove lead and arsenic ions from aqueous solutions using the activated carbon prepared from Citrus limon tree leaves. Characteristics of the prepared adsorbent were studied thoroughly using BET, SEM, EDS and mapping, XRD, and RAMAN analyses. The results of experiments showed that the highest adsorption efficiencies were 97.67% and 95.89% for Pb (II) and As (III), respectively. Additionally, the adsorbent was successfully regenerated four times and therefore it was able to perform the adsorption and desorption processes well. Moreover, the results of adsorption kinetics showed that the pseudo second-order kinetic model was more effective for the description of adsorption mechanism of both metals. Furthermore, the equilibrium studies indicated that Langmuir and Freundlich isotherm models were desirable for lead and arsenic ions, respectively.

In this study, the combustion characteristics of low calorific gas (LCG) fuels are investigated by numerical simulation. PREMIXED code is used to predict the flame structure and NO emission with two mechanisms, which are GRI 3.0 and USC II chemical reaction mechanisms for CH4 and LCG 8000 and LCG 6000, respectively. Also, elementary reactions related with production and destruction for OH radical are studied because OH radical is dominant for burning velocity and NO emission. As results, the production and the destruction of OH radical for CH4 and LCG 8000 using GRI 3.0 are dominated by reactions of No. 4, No. 2 and No. 3 and by No. 5, No. 3 and No. 7, respectively. For LCG 6000 using USC II, reactions of No. 3, No. 4 and No. 11 and of No. 7, No. 8 and No. 12 dominates to the production and the destruction, respectively. In addition, NO emissions for LCG gas fuel are generated by thermal NO because the flame temperatures are over 1800 K.

Aluminium metal matrix composites (AMMCs) are the fastest developing materials for structural applications due to their high specific weight, modulus, resistance to corrosion and wear, and high temperature strength. Carbon nanotubes (CNTs) is known as the material of the twenty-first century for its various applications in structural components for their high specific strength as well as functional materials for their exciting thermal and electrical characteristics. The present study comprise a systematic literature review of Al/CNT nanocomposites fabricated through a solid state friction stir processing. The present review is primarily focussed on the dispersion and survivability of CNTs in the Al matrix because these are the key factors in deciding the mechanical properties of the fabricated composite. Additionally, the formability, weldability and machinability of the FSPed fabricated composites reinforced with CNTs are also summarised here. Based on the detailed literature review, following research gaps are identified which require a critical and more focussed attention of the scientific community working in this research area: (i) the presence of agglomeration or clustering of CNTs in the composite, (ii) survivability and shortening of CNTs during FSP, (iii) interfacial reactions or the formation of reaction products (such as Al4C3) between Al matrix and CNTs, and (iv) the unidirectional alignment of CNTs in the fabricated composite. Important suggestions for further research in effective dispersion of CNTs with its preserved structure by FSP are also provided.

본 연구는 강원도 영월군에 위치하는 한반도습지에 분포하는 관속식물상을 파악하여 내륙습지 생태계의 식물 자원 관리보전을 위한 기초자료로 활용하고자 하였다. 조사는 2019년 4월부터 2020년 5월까지 총 9회에 걸쳐 수행하였다. 조사결과 분포가 확인된 관속식물은 93과 309 속 456종 10아종 37변종 5품종 등 총 508분류군이었다. 이 중 멸종위기 야생식물은 II급에 해당하는 2분류군이 확인 되었으며, 희귀식물은 8분류군이었다. 특산식물은 8분류 군이었으며, 식물구계학적 특정식물은 V등급에 3분류군, IV등급에 10분류군, III등급에 15분류군, II등급에 17분류군 그리고 I등급에 26분류군으로 총 71분류군이었다. 귀 화식물은 57분류군이 확인되었으며, 이에 의한 귀화율은 11.2%, 도시화지수는 17.8%로 산출되었고, 생태계교란 야생식물은 5분류군이 분포하는 것으로 조사되었다. 본 연구결과는 람사르습지에 등재되어 있어 보전가치가 매우 높은 한반도 습지의 효율적인 관리를 위한 유용한 기초자료로 활용될 것으로 판단된다.

Spirodelae Herba (SH) and Perilla Frutescens (PF) extracts have been widely used in clinical practice with various disorders for thousands of years. There are some reports regarding the anticancer effects of SH and PF each by each, but their mixture have not been investigated and their mechanisms also have not been clear. The purpose of the present study was to investigate the anticancer mechanisms and their effects of the mixture of SH and PF extracts on head and neck cancer cell line. Head and neck carcinoma KB cells were treated with SH, PF and their mixture. Anticancer effects were investigated by searching cancer cell death pathway; apoptosis and autophagy, which have been regarded to be effective and safe methods. Apoptosis, which is termed a programmed cell death, was observed by TUNNEL assay. Autophagy, which is termed a type II programmed cell death, was observed by acridine orange red staining. Additionally, the protein expressions associated with apoptosis and autophagy were detected for their mechanism by western blots. The mixture of SH and PF extracts induced autophagic and apoptotic cell death simultaneously in cancer cells. And 0.4 mg/ml of the mixture with SH and PF extracts down-regulated the expression of mTOR, however, the expressions of ATG5 and LC3-II, which induced autophagy, up-regulated. The mixture of SH and PF extracts also down-regulated the expressions of Bcl-2, but up-regulate the expressions of PARP-1 cleavage, Caspase-9 cleavage, Caspase-3 cleavage and BAX, which induced apoptosis. Taken together, these results suggested that the mixture of SH and PF extracts induce autophagic and apoptotic cell death simultaneously in head and neck cancer cells and it could be used as an alternative for anti-cancer drugs.

The April 3 victim records are a collective history of victims, including the background of the incident, the history of the victims in the process of investigating the truth and restoring honor, the process of establishing the April 3 Special Act and resolving civil-private cooperation. The Jeju 4.3 Incident occurred on Jeju Island, a small South Korean island ruled by U.S. Government amid the global Cold War and the division of the Korean Peninsula after World War II was the second most serious casualty in modern Korean history. Of the island's total population of 280,000, between 25,000 and 30,000 were found to have been killed. Nevertheless, 50 years after the incident, no specific and comprehensive fact-finding has been made, and the truth and justice have been concealed. Since the late 1980s, the damage has gradually begun to be revealed as a fierce campaign to reveal the truth of Jeju civil society, including bereaved families, students, civic groups, media, cultural circles, and academic circles. On January 12, 2000, the Jeju April 3 Incident Truth and Victim Honor Recovery Committee was launched with the enactment of the "Special Act on the Truth and Restoration of Victims". The findings were announced at the time Roh Moo-hyun, the Korean President to visit Jeju Island at a “In the past power of the state of sympathy and heartfelt apology to family and the Jeju for a mistake to say.” and came to a formal apology. In addition, the government has taken steps to overcome past tragedies and move toward the future, including the creation of Jeju April·3 Peace Park in 2003, the establishment of Jeju April ·3 Peace Foundation in 2008, the designation of national anniversaries by the government in 2012, and the declaration of formalization between the bereaved families. The April 3 victim records are a collective history of victims, including the background of the incident, the history of the victims in the process of investigating the truth and restoring honor, the process of establishing the April 3 Special Act and resolving civil-private cooperation.

Mesenchymal stem cells (MSCs) are multipotent cells capable of replicating as undifferentiated cells, and thus hold therapeutic implications in field of regenerative medicine and reproductive biotechnology. In the present study, we compared the stem cell properties of bovine ear skin tissue (ESK)- and nasal mucosa (NM)-derived MSCs. Bovine ESK-MSCs and NM-MSCs were successfully isolated by collagenase digestion and maintained proliferative capacity during the 20 consecutive passages. Both ESK-MSCs and NM-MSCs showed similar morphology and expressed common cell surface markers (CD29, CD44, CD90, and CD105). Also, we compared differentiation potentials of bovine ESK-MSCs and NM-MSCs into osteogenic, adipogenic, and chondrogenic lineages through specific staining and quantitative real-time RT-PCR. As results, bovine ESK-MSCs and NM-MSCs could differentiate into mesodermal cell lineages. However, bovine ESK-MSCs and NM-MSCs exhibited difference in expression of differentiation-related specific markers. Specifically, NM-MSCs exhibited increased expression levels of osteocalcin, peroxisome proliferator-activated receptor gamma, and aggrecan compared to ESK-MSCs. Also, ESK-MSCs exhibited increased expression levels of collagen type I, II, and lipoprotein lipase compared to NM-MSCs. We suggest that the nasal mucosa of bovine could be used as a source of bovine MSCs.

배추 재배시기에 따른 품질특성을 비교하기 위해 월별 배추의 생육특성과 이화학특성, 미생물 특성을 분석하고 군집분석을 수행하였다. 군집특성은 5-6월(I), 7월과 10월 (II), 8-9월(III), 11-12월과 1월(IV), 2-4월(V) 총 5그룹으로 분류되는데 이는 배추 작형과도 대부분 일치되었다. 주성분 분석을 통한 그룹별 특성의 경우 I 그룹은 미생물 수, II와 III 그룹은 수분함량, IV, V 그룹은 구중과 유리당 함량이 높은 것으로 분석되었다. 배추 품질특성에서 높은 상관관계를 보이는 항목은 구중과 결구율, 고형분 함량과 유리당 함량이었고, 고형분 함량과 유리당 함량을 회귀식으로 나타내면 Y(유리당) = 0.8195X(고형분 함량) - 1.2451로 나타낼 수 있는데 이를 활용해 배추의 고형분 함량으로 유리당 함량을 추정할 수 있을 것으로 판단된다. 본 연구를 통한 월별 배추의 품질특성은 해당 시기에 김치를 제조할 때 기초자료로 활용할 수 있을 것으로 기대된다.

Criticism has erupted around the world over the paper “Contracting for sex in the Pacific War” written by Mark Ramseyer, a Mitsubishi professor at Harvard University Law School. Ramseyer insists tha “comfort women” by Japanese imperial military made “credible contracts” with recruiters regardless of the Japanese government or the Japanese military. Ramseyer further insists that the “comfort women” were certified prostitutes. However, the Japanese government selected recruiters secretly and provided them with convenience in mobilizing women. Recruiters have deceived women, mainly by job fraud, into kidnapping them to military brothels. The recruiters signed with Japanese women as barmaids (shakuhu), meaning women who served drinks. However, the Japanese military brothels were prohibited from drinking. Almost Korean women were illiterate in 1940’s, so recruiters did not make contract papers with them. It was very easy to deceive Korean women to make sexual slaves of Japanese military. The surviving Japanese military’s surgeon or soldiers testified that Korean “comfort women” had been sexual slaves.

In this study, a welding heat source model was presented and verified during fiber laser welding. The multi-layered heat source model is a model that can cover most of existing studies and can be defined with a simple formula. It consists of a total of 12 parameters, and an optimization algorithm was used to find them. As optimization algorithms, adaptive simulated annealing, multi island genetic algorithm, and Hooke-Jeeves technique were applied for comparative analysis. The parameters were found by comparing the temperature distribution when the STS304L was bead on plate welding and the temperature distribution derived through finite element analysis, and all three models were able to derive a model with similar trends. However, there was a deviation between parameters, which was attributed to the many variables. It is expected that a more clear welding heat source model can be derived in subsequent studies by giving a guide to the relational expression and range between variables and increasing the temperature measurement point, which is the target value.

오스트리아와 한국은 제2차 세계대전 후 강대국들에 의해 분단되었다 는 과정상의 유사점에도 불구하고, 통일과 분단이라는 상반된 상황으로 진행되어 왔기에, 오스트리아식 영세중립화 통일방안은 국내 통일 연구 의 중요한 주제 중 하나로 고려되어 왔다. 그러나, 최근 국내 연구들이 제시하는 오스트리아식 영세중립화 통일방안의 한반도 적용 가능성은 어 떻게 오스트리아가 영세중립국으로 통일을 이뤘는지 과정을 중심적으로 다루지만, 왜 영세중립화 정책을 택하게 됐는지에 대한 논의는 이뤄지지 않는다. 이에 본고는 1955년 냉전 시기 오스트리아가 영세중립화 통일방 안을 정책으로 택하게 된 이유를 미 국무부 외교문서와 미 중앙정보부 문서에 기초하여 조사하였다. 이를 통해 오스트리아식 방안은 단순한 영 세중립화 정책이 아니라, 냉전 시기 오스트리아에 국한되어 강대국들에 의해 적용된 정책이기에, 동일한 방안을 한반도에 적용하는 것에 대한 연구는 심층적인 재고가 요구되어짐을 논하고자 한다.

환경과 식물, 식물과 식물 간의 관계에 초점을 맞추어 식물사회를 이해하기 위해 식물사회학적 방법과 사회연결망 분석을 결합한 식물사회네트워크 분석이 연구되고 있다. 식물사회네트워크는 다양한 환경에서의 식물사회 분석과 기존의 종간결합분석 방법과 비교가 필요하다. 본 연구는 무등산국립공원을 대상으로 식생구조분석을 실시하고 기존의 종간결합분석과 식물사회 네트워크를 비교 하였다. 식생조사를 위해 옛길 2구간을 대상으로 60개 조사구를 설치하여 매목조사를 실시하였다. TWINSPAN과 DCA 분석결과 60개 조사구는 해발고 800m를 기준으로 졸참나무-소나무군락(군락Ⅰ), 신갈나무군락(군락 Ⅱ)으로 나누어졌다. 출현빈도 30%이상인 수종 간 상관관계분석과 DCA분석을 실시한 후 각 군락별 주요수종을 중심으로 결과를 비교하였는데, 졸참나무와 소나무, 신갈나무는 각각 –0.450**, -0.375**로 높은 부(-)의 상관관계를 가지고 있었으며, DCA에서도 1축을 따라 졸참나무와 소나무는 가까이, 신갈나무와는 멀리 배치된 것을 확인할 수 있었다. 식물사회네트워크 분석을 위해 40개 조사구를 추가하여 100개 조사구에 출현수종을 조사하였다. 네트워크 구조 분석결과, 378개의 연결선이 나타났고, 한 수종 당 평균 6종과 결합을 가졌다. 밀도는 0.097, 지름은 7, 평균 경로거리는 2.788로 나타났다. 식물사회네트워크 분석은 기존 종간결합분석과 비교하였을 때 결과가 유사하게 나타났으며, 기존의 분석법보다 많은 양의 데이터 분석이 가능하고 식물사회 구조 관찰에 용이했다.