PURPOSES : The surface distress of asphalt pavements is one of the major factors affecting the safety of road users. The aim of this study was to analyze the factors influencing the occurrence of surface distress and statistically predict its annual change to contribute to more reasonable asphalt pavement management using the data periodically collected by the national highway pavement data management system. METHODS : In this study, the factors that were expected to influence the surface distress were determined by reviewing the literature. The normality was secured by changing the forms of the variables to make the distribution of the variables got closer to normal distribution. In addition, min-max normalization was performed to minimize the effect of the unit and magnitude of the candidate independent variables on the dependent variable. The final candidate independent variables were determined by analyzing the correlation between the annual surface distress change and each candidate independent variable. In addition, a prediction model was developed by performing data grouping and multi-regression analysis. RESULTS : An annual surface distress change prediction model was developed using present surface distress, age, and below 0 ℃ days as the independent variables. As a result of sensitivity analysis, the surface distress affected the annual surface distress change the most. The positive correlation between the dependent variable and each independent variable demonstrated engineering and statistical meaningfulness of the prediction model. CONCLUSIONS : The surface distress in the future can be predicted by applying the annual surface distress prediction model to the national highway asphalt pavement sections with survey data. In addition, the prediction model can be applied to the national highway pavement condition index (NHPCI) evaluating the national highway asphalt pavement conditions to be used in the prediction of future NHPCI.

Abstract In this study, micro-defects on/in carbon fibers were modified by irradiation with an electron beam, which improved the mechanical strength of single carbon fibers. The electron beam irradiation was 10 kGy (using a 1.5 MeV accelerator in the air). The total doses ranged from 100 to 500 kGy. The tensile strength of the single carbon fiber was measured using a universal testing machine. The micro-defects on the fiber surface were observed with scanning electron microscopy and atomic force microscopy, and those in the fiber were evaluated by Raman spectroscopy. In conclusion, the electron beam treatment produced changes in the micro-defects on/in the carbon fibers, resulting in up to 14% improvement in the tensile strength of single carbon fiber.

13세기 몽골침략은 페르시아의 사상, 종교, 문화에 전반적인 영향을 주었다. 그 중 몽골지배 이 전과 대비하여 가장 극명한 차이를 보이는 것은 이슬람 신비 주의 종교철학인 수피즘에 대한 인식 변화이다. 이슬람 왕조의 세속주의와 향락 에 대한 반작용으로 태동한 수피즘은 12세기 페르시아에서 종단이 세워지면서 하나의 기득권층이 되었으며, 몽골침략 이 후 몽골지배층과 결탁하여 이민족의 정권을 선전하는 수단이 되었다. 이러한 과정에서 금욕과 청빈이 미덕인 수피들 은 부패하기 시작하였고, 14세기 몽골족 지배하에 활동했던 하페즈와 같은 시 인들은 자신들의 시에서 이러한 수피들을 비판하였다. 본 연구에서는 페르시아 의 시성인 하페즈의 작품에 나타난 수피 상징 연구를 통하여 몽골 침략 이 후 수피에 대한 인식 변화를 보여주고자 한다.

We conducted a field survey from 2018 to 2020 to analyze the spatial distribution of phytoplankton communities at 13 stations in the East Sea. The diatom Chaetoceros curvisetus appeared as the dominant species in winter, and small flagellates less than 20 μm prevailed in all seasons except winter. The seasonal average range of the micro (>20 μm), nano (20 μm≥Chl-a>3 μm), and picophytoplankton (≤3 μm) was 20.6-26.2%, 27.1-35.9%, and 40.8-49.0%, respectively. The composition ratio of nano and picophytoplankton was high at the surface mixed layer from spring to autumn when the water columns were strongly stratified. Especially, the stability of the water mass was increased when the summer surface water temperature was higher than that of the previous year. As a result, the nutrient inflow from the lower layer to the surface was reduced as the ocean stratification layer was strengthened. Therefore, the composition ratio of nano and picophytoplankton was the highest at 77.9% at the surface mixed layer. In conclusion, the structure of the phytoplankton community in the East Sea has been miniaturized, which is expected to form a complex microbial food web structure and lower the carbon transfer rate to the upper consumer stage.

This study analyzed the relationship between the community structure of benthic macroinvertebrates and habitat changes in open estuaries among the sites included in the national estuary monitoring program. The estuary survey was conducted under the “Guidelines for Investigation and Evaluation of Biometric Networks” and classified by sea area, 80 places in the East Sea, 102 places in the South Sea, and 19 places in the West Sea were investigated. In a total of 201 open estuaries, benthic macroinvertebrates were identified with 4 phyla, 9 classes, 41 orders, 139 families, 269 species and 196 species in the East Sea, 182 species in the South Sea, and 90 species in the West Sea. The highest population densities were Insecta in the East Sea, the Malacostraca in the South Sea, and the Annelida in the West Sea. Through SIMPER analysis, species contributing to the similarity of benthic macroinvertebrates communities in each sea area were identified. Some species greatly influenced the similarity of clusters. The benthic community in the East Sea was affected by the salinity, so the contribution rate of freshwater species was high. On the other hand, the benthic communities of the South and West Seas showed species compositions are influenced by the substrate composition. As results, the benthic macroinvertebrate community in Korean estuaries was impacted by salinity and substrate simultaneously, and the close relationship with geographical distance was not observed. The result of this study is expected to be used to respond to environmental changes by identifying and predicting changes in the diversity and distribution of benthic macroinvertebrates in Korea estuaries.

Currently, the construction trend of high-rise structures is changing from a cube-shaped box to a free-form. In the case of free-form structures, it is difficult to predict the behavior of the structure because it induces torsional deformation due to inclined columns and the eccentricity of the structure by the horizontal load. For this reason, it is essential to review the stability by considering the design variables at the design stage. In this paper, the position of the weak vertical member was analyzed by analyzing the behavior of the structure according to the change in the core position of the twisted high-rise structures. In the case of the shear wall, the shear force was found to be high in the order of proximity to the center of gravity of each floor of the structure. In the case of the column, the component force was generated by the axial force of the outermost beam, so the bending moment was concentrated on the inner column with no inclination.

본 연구의 목적은 예비 지구과학교사들이 학생에 의해 구성된 기후변화 모델을 평가하는 기준을 탐색하는 것이 다. 대도시 소재 대학 지구과학교육과 전공 수업에서 3주간 모델링 기반 과학 학습에 대한 강의를 수강한 예비 지구과 학교사 25명이 연구에 참여하였다. 예비 지구과학교사들이 작성한 고등학생들이 구성한 7개의 기후변화 모델을 평가하 는 보고서와 사후 인터뷰 자료를 수집하여 기후변화 모델 평가 기준을 귀납적으로 범주화하였다. 연구 결과 예비 지구 과학교사들이 기후변화 모델을 평가할 때 다양한 인식론적 기준과 의사소통 기준을 동원하였음을 확인하였다. 연구 결 과를 바탕으로 모델링 기반 기후변화 학습에 대한 시사점을 도출하였다.

When the CP voltage is disconnected, the measured voltage on the ICCB side is measured to be 12V, and the voltage on the OBC side is measured to be 0V. When the PD signal was disconnected, the ICCB-side measured voltage was 0V and the OBC-side measured voltage was 4.5V. From this, disconnected position be found with the voltage value measured. When CP was disconnected for a short time, the PD voltage did not change to 1.5V, and when the PD was disconnected, the CP signal and PD signal changed to 9V, and if the CP and PD voltages were normal, the charge control could be performed normally.

Demand for CFRP with new characteristics is increasing in various industrial fields, from parts materials to daily necessities, and research on this is also being actively conducted. CFRP is a material that realizes properties suitable for multiple functions that cannot be seen in a single material by physically combining two or more materials with different shapes and chemical compositions. When machining CFRP using a high-speed steel (HSS) drill or a TiAlN-coating drill with different rotation speed and feed speed, the cutting force was experimentally analyzed and the optimal tool material and cutting conditions were selected. The cutting force according to the change in rotation speed of the high-speed steel drill and the TiAlN-coating drill is compared.

Conversion to modern hydrogen energy is required, and research on liquefied hydrogen cargo containment systems is needed for large-capacity transport and storage. In this study, changes in the mechanical properties of the adhesive required for storage and transport in liquid hydrogen were confirmed. The lap shear test was performed by realizing cryogenic conditions in a small chamber using liquid nitrogen and liquid helium. There was an increase of 11.0% in the -180℃ condition compared to room temperature, and an increase of 1.8% in the -230℃ condition compared to the -180℃ condition was confirmed. In the case of shear strain, it is known that it decreases as the temperature goes down. As a result of the experiment, it was confirmed that the value at room temperature and the value at -180℃ reduced the shear strain by 5.0%, and -230˚ compared to the -180℃ condition. An increase of 1.5% was confirmed in the C condition. In the case of the specimen tested at -230℃, the deformation in the gripper part was larger than in other tests, and it is judged that the maximum shear strength and shear strain were affected. In addition, in this study, there is a limitation in the experiment at -230°C rather than 253°C, which is the boiling point of hydrogen

본 연구는 MRCP 검사에서 대부분 시간이 소요되는 T2 3D 검사 시 CS 기법을 적용해 시간을 단축하고 동시에, CS 계수와 De-noising 계수를 변화시켜 그에 따른 영상 변화에 관하여 연구하고자 하였다. 본 연구는 환자 대신에 3D 프린터를 사용하였으며, 지름 0.55cm인 실리콘 bile duct를 제작하여 실험하였다. 실험 조건은 CS 계수를 1.1, 5, 10, 15, 20, 25로 변화시켰으며, 각각 변화된 CS 계수마다 De-noising 계수를 1, 100, 250, 500, 750, 1000으로 변화시켜 설정된 조건으로 5번씩 검사를 시행하고, 나머지 매개변수는 같게 하여 영상을 획득하였다. 계수 설정 별로 획득된 영상을 SNR, CNR, SSIM 값 순으로 측정하여 비교, 평가하였으며 검사 소요 시간의 변화도 측정하였다. 실험 결과 CS 계수를 기준으로 De-noising을 변화시킨 그룹과 De-noising 계수를 기준으로 CS 계수를 변화시킨 그룹에서 SNR과 CNR 전체적으로 유의하게 감소하였다(p<0.05). 또한, 검사 소요 시간은 CS 계수의 변화에 따라 많이 감소하였다. 특징적으로는 모든 계수 를 변화시킨 그룹에서 De-noising 계수 10, De-noising 계수 100의 그룹이 SNR과 CNR이 가장 높았으며, 구조적인 유사도를 측정하는 SSIM 값도 가장 높은 것으로 나타났다(p<0.05). 결론적으로, 환자의 호흡정지 기법이 가능한 CS 계수 15 이상에서 De-noising 10 또는 De-noising 100의 조합이 영상의 질과 검사 소요 시간에 있어 가장 최선의 계수 설정이며, 특히 CS 계수 20, De-noising 계수 100의 영상이 기준 영상 SNR의 90%, CNR의 97.2%, 구조적 유사성 98.7%로 가장 우수한 설정값으로 나타났다. 본 연구의 CS 계수와 De-noising 계수의 설정은 영상의 질적 수준을 일정 수준 유지하며, MRCP 검사에서 많은 시간이 소요되는 T2 3D sequence의 검사소요 시간을 단축시켜 진단적인 능력은 유지하며 검사 소요 시간을 줄이는 기초자료로 사용 될 것이라고 사료된다.

프로펠러축은 프로펠러 하중 및 편심추력의 영향으로 인해 정적, 동적, 과도상태 각각 거동의 패턴이 달라져 선미관 후부베어 링의 국부하중 변화를 일으킴으로써 선박 축계의 안정성에 큰 영향을 미치며, 결과적으로 축 지지 베어링의 손상위험을 증가시킨다. 이를 방지하기 위한 일련의 축계정렬연구는 선급강선규칙과 조선소 지침을 기반으로 준정적 상태에서 축과 선미관 베어링간의 상대적 경사각 과 유막유지, 선체변형에 따른 영향평가를 최적화 하는데 중점을 두어 진행 되어왔다. 그러나 보다 진일보한 형태의 추진축계의 안정성을 보장하기 위해서는 조타장치의 전타시 발생하는 급격한 선미유동장 변화와 같은 과도동적상태변화 조건에서의 상세 연구가 필요하다. 이 러한 관점 하에 본 연구에서는 50,000 DWT 중형 유조선을 대상으로 스트레인 게이지법과 변위센서을 이용하여 선박운전 중 대표적 과도 상태인 좌현 전타시의 프로펠러 축 거동이 선미관 베어링에 미치는 영향을 교차검증한 결과, 프로펠러 편심추력변동이 선미관 베어링의 하중을 일시적으로 저감시켜 베어링 하중을 완화시키는 것을 확인하였다.

China-US relations have become the focus of world attention after the Biden administration took power. Some predict that Biden‘s strategy in the early days of his administration will be a combination of Obama’s and Trump‘s Policies toward China, which focus on competition rather than reconciliation and cooperation. Biden stated clearly that he has no intention to involve in a“new cold war”with China, he will not deliberately exclude engagement with China, he also has proposed that intensive cooperation with China will be put into effect on the theme related to climate change, global public health and nuclear non - proliferation. Meanwhile, the Biden administration continues to claim that China is the Unites States’ “most rigorous competitor”. The US government will carry out a series of strategic policy in the areas of economy, security, diplomacy, human rights, intellectual property, and global governance. the Biden administration continued to promote the Indo-Pacific strategy more actively in order to achieve the upgrading of the four-country dialogue mechanism with Japan, India and Australia and also make great effort to strengthened the relationship of traditional Allies, by which achieving the goal of containing China. With the framework of the “One China” policy, the Biden administration intend to strengthen unofficial relations and non-government contact with Taiwan to improve Taiwan‘s self-defense capability and international visibility aim to maintain the status quo of“no independence”and“no unification”between Taiwan and the mainland. For the foreseeable future, Biden will inherit the tone of the Trump administration‘s strategic competition toward China through some necessary political adjustment. the China-US relations will be imbued with challenge and opportunities.

The present study investigated the effect of global warming on germination and initial growth across six deciduous oak species (Quercus mongolica, Q. variabilis, Q. serrata, Q. dentata, Q. aliena, and Q. acutissima), which are the dominant tree species in Korea forest ecosystems. Seeds were sown in climate change treatments, with temperatures higher than those of the control (approximately 3.0°C higher), and CO2 concentrations higher than those of the control (approximately 2-fold higher). Initial growth in each species was measured every two weeks. Initial growth was more rapid in all oak species at the time of root and shoot emergence under high temperature and CO2 treatments than in the control group. Leaf emergence in Q. mongolica, Q. variabilis, and Q. serrata occurred earlier under the climate change treatments than under the control. Root length increased significantly in Q. mongolica, Q. variabilis, and Q. dentata under the climate change treatments when compared to under the control. However, Q. aliena and Q. serrata exhibited a contrasting trends, and no significant difference was observed between the species and Q. acutissima. Shoot length increased significantly in Q. aliena under climate change treatments when compared to under the control but decreased in Q. aliena. In addition, no significant difference was observed in shoot length among Q. mongolica, Q. dentata, and Q. acutissima. The results showed that climate change treatments facilitated early growth, rapid emergence from the ground, leaf development, and enhanced belowground growth in Q. mongolica. Conversely, Q. aliena exhibited the lowest aboveground and belowground growth under climate change treatments when compared to other oak species. Climate change treatments had the least impact on Q. acutissima considering the insignificant differences observed in initial growth rates under climate change treatment.

본 논문은 기후 부정의한 상황에 대한 정책 방향을 기후정의 관점에서 모색하기 위한 시론적 연구 이다. 전세계 곳곳에서 폭염, 호우, 가뭄 등 전례 없는 현상으로 나타나는 기후변화는 지구와 인류의 생존을 위협하게 되었고, 세계는 이에 대응하는 방법을 모색하고 있다. 그러나 2021년 11월에 개최된 26차 유엔기후변화협약 당사국총회(COP26)가 각국의 이익을 우선시하는 국가들에 의해 충분한 성과를 내지 못함에 따라, 국제적 기후변화 대응의 어려운 현실이 다시금 드러나게 되었다. 각국의 협의를 어렵게 만드는 요인 중의 하나는 기후변화가 내포하는 불평등에서 찾을 수 있다. 인류 모두에게 닥친 기후위기는 모든 사람들에게 동일한 정도의 피해를 주지 않으며, 기후변화를 초래한 대상과 피해자가 일치하지 않는 불평등의 문제를 갖고 있다. 탄소배출로 부를 축적하고 더 많은 탄소를 배출한 유발자와 그로 인한 피해자가 일치하지 않는 문제의 인식에서 ‘기후 부정의’와 ‘기후정의’가 논의되기 시작하였다. 기후위기의 부정의한 상황은 국가 간, 계층 간, 세대 간의 불평등을 악화시키고 기후위기 대응의 걸림돌이 된다. 본 연구는 기후위기의 부정의한 상황을 분석하고, 국제 사회와 한국사회의 대응 방향을 돌아보고자 한다. 기후정의 관점을 통해 기후위기의 불평등 문제가 드러나고 기후변화 대응책 마련에 유용한 분석틀을 제공할 수 있기를 기대한다.

목적: 본 연구는 연령증가에 따른 안경굴절검안에 있어서 조절반응과 조절지체 간의 변화량의 영향 관계를 검정하는데 있다. 방법 : 연령증가에 따른 원점과 근점의 자극에 대응하는 조절 반응점 (ARf, ARn)을 연구하기 위해서, 선조 검영기를 사용하여 정시 74개 (남: 37, 여: 37)의 단안을 대상으로 굴절검사를 진행하였다. MEM 0.4 시력카드의 스넬린 (Snellen chart) E 단일문자를 검영기헤드 (No 18235, WelchAllyn, USA) 전면에 부착한 선조 검영기를 사용하여 조절 반응을 확인하였다. 결과 : 연령증가에 따른 원점 조절반응의 경우Ⅰ>Ⅱ, Ⅲ, Ⅳ의 유의한 결과를 보였고, 나머지 근점 조절반응과 조절지체는 Ⅰ, Ⅱ, Ⅲ<Ⅳ의 결과를 보여주었다. 연령증가에 따른 원점 조절반응과 조절지체 간의 통계적 조절효 과는 Ⅰ·Ⅱ〉Ⅰ·Ⅲ〉Ⅰ·Ⅳ의 유의한 결과를 보였다. 결론 : 40대 이후 연령의 증가에 따른 시축상의 원점 조절반응의 절댓값과 조절지체는 각각 감소하고 증가함에 따라 원거리 안경굴절검사를 위한 안와 내 조절반응의 기준점을 달리 적용하여야 한다.

In modern times, where problems due to environmental pollution are continuously occurring, hydrogen is in the spotlight as the energy of the future. Hydrogen is an eco-friendly energy resource that does not even generate CO2, and is actively supporting research to utilize hydrogen energy at the national level. This study is a study on the cryogenic mechanical properties of the elements constituting the cargo hold during the transportation of liquid hydrogen. Among the various components, the evaluation of mechanical properties of the cryogenic adhesive under liquid helium conditions was confirmed. The related contents are summarized as follows. As a result of performing SSRT by curing the adhesive, it was confirmed that tensile strength and maximum strain were increased at cryogenic temperature (-230°C) compared to room temperature (25°C). It was confirmed that the adhesive-hardened specimen showed a brittle fracture mode at both room temperature and cryogenic temperature during tensile. Improvements in this study, such as pores occurring during adhesive curing, the use of standard specimens, and experiments at -253°C, the boiling point of hydrogen, exist, and are planned to be carried out in subsequent studies.

To increase the utilization of Centella asiatica (CA), enzymes such as cellulase and pectinase were added and the physicochemical properties of the treated CA were analyzed. In addition, apple-CA jam was prepared using the enzyme-treated CA, which had the best antioxidant properties, and the physicochemical and sensory qualities of the jam were measured. There was a high content of ascorbic acid, polyphenols, flavonoids, reducing sugar, amino acid, minerals and DPPH radical scavenging activity in the enzyme-treated group. The antioxidant component and activity in the jam prepared by adding enzyme-treated CA increased with an increase in the amount of enzyme-treated CA. In the soluble solids, the higher the amount of enzyme-treated CA, the higher the value, but there was no significant difference in pH. The sensory evaluation of the jam, in particular the taste, showed that the highest preference was observed when the enzyme-treated CA was added in the range of 5.0~6.7%, and the control group showed the lowest preference. There was no significant difference in flavor and spreadability among the treatment groups, however, the control group showed the highest color preference. In the overall acceptability, when 5.0% of enzyme-treated CA was added, the highest acceptability was shown.