In this study, we examined dimensional changes in processing carbon fiber composites using a cost-competitive domestic high-speed router. Lacking temperature compensation features found in typical machines, it faces increased defect rates due to temperature fluctuations during processing. To mitigate this, we defined specific processing temperature conditions, established hole positions as distance references for various temperatures, and measured dimensional changes. This enabled us to calculate necessary dimensional corrections, minimizing thermal deformation.

In Korea, borated stainless steel (BSS) is used as a storage rack in spent fuel pools (SFP) to maintain the nuclear criticality of spent fuels. As the number of nuclear power plants and the corresponding amount of spent fuels increased, the density in SFP storage rack also increased. In this regard, maintaining subcriticality of spent nuclear fuels became an issue and BSS was selected as the structural material and neutron absorber for high density storage rack. Since it is difficult to replace the storage rack, corrosion resistance and neutron absorbency are required for long period. BSS is based on stainless steel 304 and is specified in the ASTM A887-89 standard depending on the boron concentration from 304B (0.20-0.29% B) to 304B7 (1.75-2.25% B). Due to the low solubility of boron in austenitic stainless steel, metallic borides such as (Fe, Cr) 2B are formed as a secondary phase. Metallic borides could cause Cr depletion near it, which could decrease the corrosion resistance of the material. In this paper, the long-term corrosion behavior of BSS and its oxide microstructures are investigated through accelerated corrosion experiment in simulated SFP conditions. Because the corrosion rate of austenitic stainless steel is known to be dependent on the Arrhenius equation, a function of temperature, the corrosion experiment is conducted by increasing the experimental temperature. Detail microstructural analysis is conducted using a scanning electron microscope, transmission electron microscope and energy dispersive spectrometer. After oxidation, a hematite structure oxide film is formed, and pitting corrosion occurs on the surface of specimens. Most of the pitting corrosion is found at the substrate surface because the corrosion resistance of the substrate, which has low Cr content, is relatively low. Also, the oxidation reaction of B in the secondary phase has the lowest Gibbs free energy compared to other elements. Furthermore, oxidation of Cr has low Gibbs free energy, which means that oxidation of B and Cr could be faster than other elements. Thus, the long-term corrosion might affect the boron content and the neutron absorption ability of the material. Using boron’s high cross-section for neutrons, the neutron absorption performance of BSS was evaluated through neutron transmission tests. The effect of the corrosion behavior of BSS on its neutron absorption performance was investigated. Samples simulated to undergo up to 60 years of degradation before corrosion through accelerated corrosion testing did not show significant changes in the neutron shielding ability before and after corrosion. This can be explained in relation to the corrosion behavior of BSS. Boron was only leached out from the secondary phase exposed on the surface, and this oxidized secondary phase corresponds to about 0.17% of the volume of the total secondary phase. This can be seen as a very small proportion compared to the total boron content and is not expected to have a significant impact on neutron absorption performance.

본 연구의 목적은 디지털 트랜스포메이션의 도입이 가속화 된 경영 환경 속에서 조직 내 인적자원개발(human resource development: HRD) 담당자들이 경험하는 업무 변화에 대해 알아보고, 그에 따른 필요역량 및 업무 수행 시 겪는 어려움을 탐색하는데 있다. 이러한 목적을 달성하기 위해 HRD 업무를 담당하는 현직 종사자 10명을 대상으로 하여 일대일 심층 인터뷰를 실시하였다. 그 결과 디지털 트랜스포메이션시대에 HRD 담당자의 업무는 NCS 기반의 능력단위를 기준으로 하여 전통적인 업무와 비교했을 때 강화, 감소 또는 새롭게 추가된 업무가 있는 것으로 나타났다. 또한 필요 역량은 지식, 기술, 태도, 능력이라는 범주로 나누어 도출하였는데, 테크놀로지 활용 기술 및 변화에 적극적이고 긍정적으로 대응하려는 태도 및 능력이 중요한 것으로 나타났다. 전체적으로 디지털 트렌드 및 스킬에 대한 지속적인 학습으로 인해 업무량은 증가한 것으로 나타났다. 이상의 결과를 바탕으로 본 연구에서는 조직원들의 변화를 이끌어가야 하는 HRD 담당자들에게 실천적 시사점을 제시하고, 연구의 제한점 및 향후 연구 방향에 대하여 제언하였다.

It can take hundreds of thousands of years for decreasing radiological effects of high-level radioactive wastes to those of natural background radiation. Therefore, long-term time scale should be considered in order to demonstrate performance and safety of deep geological disposal of the radioactive wastes. The changes of surface environment for these long-term time scale can have influence on safety analysis by changing transport path of radionuclides from the radioactive wastes. Changes in climate is considered as one of main factors causing the long-term changes of the surface environment. The own effects and interactions of climate with other components of the geological disposal system are organized in features, events, and processes (FEPs). In this study, some natural processes occurred by changes of climate were suggested and the connectivity between each process is proposed based on the relation of the FEPs concerned with the changes of climate and surface environment. The processes were classified into global and regional/local scales and was analyzed, respectively. Then, the influences of the processes on shallow groundwater and surface water body environment, which might be transport path of radioactive nuclides in local/site scales, were expected. As the proposed connection demonstrate the order or hierarchical relations of the natural processes, it can shows that some output by a certain process may be input of other process connected the former process in numerical simulations for interpreting the processes. If the connection may be considered to be suitable to represent longterm changes of the surface environment, it can be evaluated that the expected scenarios based on the connection is also proper. In addition, it can be helpful in selecting factors to be studied more detailed in terms of climate change for expecting long-term changes in the surface environment by analysis on the input and output data. The results of this study can be used as basic approaches to represent the long-term changes in the surface environment caused by specific natural processes from changes of climate. It will be also helpful for formulating scenarios related to long-term evolution in the surface environment required for performance and safety assessments of the deep geological disposal.

본 연구는 학원강사가 지각하는 직무환경, 직업정체성, 직업변경의도에 대한 인식을 알아보고, 직업정체성 및 직업변 경의도에 영향을 미치는 요인을 분석하였다. 학원강사의 직무환경을 개선하고 직업정체성을 높임으로써 직업변경의도를 낮출 수 있는 방안을 모색해 보고자 하였다. 이러한 연구목적을 달성하기 위하여 학원강사(입시·보습학원)를 대상으로 설문조사를 통하여 자료를 수집하였다. 자료 분석은 391명의 응답을 바탕으로 IBM SPSS Statistics 26.0 프로그램을 이 용하여 수행하였다. 주요 연구결과는 다음과 같다. 첫째, 학원강사가 지각하는 직무환경 및 직업정체성은 보통 수준으로, 직업변경의도는 보통 이하 수준으로 나타났다. 직무환경에서 복리후생 및 안정감은 입시학원이 보습학원보다 높았고, 인간관계는 비율제 강사가 월급제 강사보다 높았으며, 직업변경의도는 교육청에 등록한 월급제 강사가 교육청에 등록하지 않은 비율제 강사 보다 높은 것으로 나타났다. 둘째, 학원강사의 직업정체성은 학원의 복리후생, 안정감, 직업평판, 인간관계가 좋을수록 증가하며, 사회보험에 가입 안되어있는 강사가 가입되어 있는 강사보다 높은 것으로 나타났다. 직업변경의도는 학원의 안정감이 높고, 시설·설비, 자 부심, 헌신의 수준이 낮을수록 높은 것으로 나타났다. 셋째, 학원강사의 직무환경이 직업변경의도에 영향을 미치는 관계 에서 직업정체성은 완전매개효과가 있는 것으로 나타났다. 결론적으로 학원경영자는 학원강사의 직무환경을 개선함으로 써 학원강사의 직업정체성을 높일수 있는 방안을 모색하고, 학원강사의 직무환경, 직업정체성, 직업변경의도 간의 관계 와 영향력을 고려해서 인사관리를 하여야 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.

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.

In this article, firstly, we talk about why we respond to “climate change impacts in nature and society” educationally. Secondly, we try to find ways that Jeju also has the ability to halt biodiversity loss and apply nature-based solutions to conserve biodiversity, enhance resilience, and so improve the well-being of the people on the island and in turn to improve the well-being of the people on the planet at the grass roots level of UNESCO internationally protected areas. Thirdly, we try to develop World Environment University Online School Leads Establishment of World Environment University so called “Lead WEU.” We will announce “World Environment University Online School Leads Establishment of World Environment University” at Private Meeting of the 2020 World Conservation Congress on September 9, 2021 in Marseille of France. We propose ”Jeju Global Governance of World Heritage; Climate Change Impacts and Integrated Management of UNESCO internationally Protected Area, at the graduate class of Jeju National University from September 2 to December 9, 2021. The core program centered at the University itself would be developed initially on the basis of the comparative advantage offered by its location in Jeju and the quality of faculty, full and part time, that could be recruited to the University.

굴 패각을 입경(0 ~ 1, 1 ~ 2, 2 ~ 5 mm) 및 소성온도(400(P400), 500(P500), 600(P600), 800(P800)℃)별로 전처리 한 후, 퇴적물과 혼합 된 실내실험을 통해 퇴적물의 성상변화를 조사하였다. 굴 패각의 주요 성분인 CaCO3는 700℃ 이상의 소성 온도에서 열분해 되어 CaO로 변화하는 것으로 나타났다. P800의 Ca2+ 농도는 약 790 mg/L로 대조구 및 다른 실험구들에 비해 약 2 ~ 3배 높게 나타나 고온 소성 된 굴 패각일수록 용출되는 Ca2+는 높은 것으로 확인되었다. 600℃ 이상의 온도에서 소성된 굴 패각에서는 CaCO3의 열분해로 형성된 CaO의 가수분해를 통해 간극수 내의 pH가 0.1 ~ 0.5 증가한 것으로 나타났다. 간극수 내의 NH3-N은 대조구보다 약 2.2 ~ 7.6 mg/L의 범위로 증가하였으며, 이는 가수분해 과정에서 발생한 열, Ca2+에 의한 미생물 활동 억제, 소성 과정에서 증가한 굴 패각 공극을 통한 산소 공급 등이 복합적으로 작용한 결과로 판단된다. P600 및 P800의 직상수 및 간극수 내의 PO4-P 농도는 대조구보다 약 0.1 ~ 0.2 mg/L 낮게 나타났으며 이는 소성 굴 패각으로 인한 pH 증가 및 PO4-P와의 화학적 반응으로 판단된다. 이상의 결과를 통해 소성 온도에 따라 굴 패각은 퇴적물 내의 NH3-N 및 PO4-P의 농도변화에 영향을 미치는 것으로 확인되었으나, 입경에 의한 영향은 크지 않은 것으로 확인되었다. 본 연구의 결과는 향후 소성 굴 패각을 낮은 오염도의 연안 저서환경을 개선시키기 위한 기초자료로 활용 될 수 있을 것을 판단된다.

Statistical modeling to predict community change for large geographical scale is difficult when community responses to similar climate changes differ among regions. This study attempted to present a solution for this problem by predicting species responses to local environment. Our model for predicting community change consisted of species response models to local environmet parameters, in which the estimated abundance of each species was used to reconstruct the community composition. Our method was verified by data from continuous surveys at Hyangrobong, Odaessan and Taebaeksan in Gangwon-do, in which environmental factors and ground beetle community at each site were continuously recorded. We show our method performes better than an ordinary model that predicts directly a change in the community.

When weapon system is designed and developed, a reliability is one of important factors to determine the development goal. The reliability analysis of the weapon system and equipment is based on MIL Specification, MIL-HDBK-217F and MIL-HDBK-338B. And the weapon system is operated on various environments by operating concept of the military using the weapon system. This study, at first, present failure rate by PSA comparing with failure rates by PCM, the different reliability analysis method, for same CCA(Circuit Card Assembly). And the study present change of reliability analysis results for CCA on various operation environment condition..

In constructing the cast-in-place concrete track system, the installation of reinforcing bars to a TCL is one of the main causes of consuming construction time. In this study, to eliminate the reinforcing bar installation process, the applicability of the fiber reinforced concrete to the TCL is studied using the numerical analysis. The analysis is performed using the commercial finite element program, ABAQUS, and, in the analysis, the effect of the variations in fiber content rate and the surrounding temperature is considered. From the analysis, it is found that the fiber reinforced concrete has better applicability than the existing reinforced concrete with steel bar.

본고는 사료의 重層性을 전제로 실직국의 복속 과정과 이에 대한 신라의 지배 형태 변화를 파악하는 데 목적을 두었다. 실직국의 복속을 전하는 󰡔삼국사기󰡕 신라본기 파사이사금 23년조는 󰡔삼국유사󰡕 왕력 지마이질금조와 저본을 달리해 작성되었다. 그 저본의 찬자는 실직국과 음즙 벌국 사이의 분쟁, 그리고 사로국의 중재에 대한 자료를 소재로 실직국의 항복 과정까지 하나의 사건으로 합쳐 정리했다. 파사대의 정복기사는 탈해대·지마대의 대외확장을 강조한 기사와 저본을 달리해 重層的으로 봉합되었다. 파사 23년조는 대외확장에서 파사이사금의 업적을 중시한 저본에 토대를 두었다. 왕력 지마이질금조는 신라본기 파사23년조보다 상대적 신뢰도가 높지만, 절대적 신뢰도를 담보하지 않는다. 실직국은 옥계, 하장, 원덕 일대를 지배했다고 전하는데, 실제 지배 범위는 변화했을 가능성이 있다. 특히 동해시 송정동 일대에도 大邑落이 존재했을 것이다. 실직국은 동해안 교통로와 영서 방향 교통로의 결절지라는 입지조건, 동예와 진한의 중간적 위치 등을 기반으로 주변 邑落을 통제했고, 음즙벌국과 동해안의 교역로를 두고서 경쟁했다. 3세기 후반∼말경 동해안의 교역 에서 사로국이 금관국에 대해 우위를 보이면서 실직국은 사로국이 주도하는 교역에 협조하기 시작했다. 4세기 초중엽부터 사로국과 고구려의 교섭이 본격화하면서 실직국은 사로국에 복속했다. 실직국 干層은 공납을 바치고 기항지 이용권을 제공하는 대신, 읍락 간층에 대한 통제권을 유지했다. 실직국의 반란이 진압된 뒤에도 일부 간층은 자치권의 일부를 유지했다. 실직 지역은 何瑟羅城에 비해 방어기능이 약한 편이었다. 그런데 5세기 중엽부터 고구려가 남한강 상류 방면으로부터 압박해 오면서 悉直城의 據點城 기능은 강화되었고, 간층의 자치권은 약화되었다. 실직성 주변의 읍락들은 5 세기 후반경 村으로 편성되었다. 5세기 말 이후 신라는 거점성별로 전략적 기능과 옛 소국에 대한 지배기능을 조정했다. 이 과정에서 실직성이 다수 거점성에 대한 관리 기능을 부여받아 505년에 悉直州가 설치되었다. 6세기 초까지 유력 간층을 대상으로 복수의 干群 外位와 非干 외위가 편성되었다. 간군 외위자는 비간 외위 자의 보위와 非외위자의 협조로 道使의 통치에 협조했다. 그런데 512년 何瑟羅州 설치, 524년 이전 실직주 재설치 등에 따라 외위의 운영은 변화했을 것이다.