Multivalent ions in natural aqueous solutions—such as seawater, brackish water, and freshwater—can negatively affect the performance of ion exchange membranes (IEMs) used in electrochemical energy and environmental devices. In this study, a pore-filling cation exchange membrane (CEM) permeable to multivalent ions was fabricated to minimize performance degradation caused by such ions. To achieve this, multilayer pore-filling CEMs were prepared by performing two impregnation processes using monomer electrolyte solutions of different compositions (varying deionized water content and monomerto- crosslinker ratios). As a result, a highly crosslinked electrolyte polymer formed on the internal side of the CEM, while a low-crosslinked polymer formed on the external side. Due to the presence of the low-crosslinked outer polymer layer, the multilayer pore-filling CEM exhibited a smaller increase in resistance caused by Mg2+ ions. Furthermore, based on the correlation between permselectivity and resistance measured in a 0.45 M NaCl + 0.05 M MgCl2 solution, which simulated the Mg2+ concentration in seawater, an optimal structure of multilayer pore-filling CEM was identified, and it exhibited a minimized increase in resistance and a permselectivity of over 90 %.

본 연구는 여성요양보호사의 직무스트레스와 노인학대인식의 관계에서 직 무환경의 매개효과를 검증하는 데 그 목적이 있다. 이를 위해 2025년 1월 2 일부터 2025년 1월 31일까지 k시의 노인요양 시설에 근무하는 여성요양보호 사를 대상으로 설문조사를 실시하였으며, 총 357명의 응답을 분석에 활용하 였다. 자료분석은 자료분석을 SPSS 25.0과 AMOS 25.0 프로그램을 사용하 여 기술통계, 상관관계 분석, 구조방정식 모형분석을 하였으며, 직무환경의 매개효과 분석을 위해 헤이즈(Hayes 2012)가 고안한 Process Macro Mode l 4를 활용했다. 본 연구결과, 첫째, 요양보호사의 직무스트레스는 노인학대 인식에 정적 영향을 미치는 것으로 나타났다. 둘째, 요양보호사의 직무환경 은 노인학대인식에 정적 영향을 미치는 것으로 나타났다. 셋째, 요양보호사 의 직무스트레스와 노인학대인식의 관계에서 직무환경이 부분 매개효과를 가지는 것으로 나타났다. 이러한 결과는 여성요양보호사의 노인학대인식의 중요성을 시사하고 있으며 이를 증진하기 위해 다각적인 노력에 실증적인 자료로 활용될 것으로 사료된다.

최근 동해 연안(≤300m)의 도루묵(Arctoscopus japonicus) 자원량의 급격한 변동 원인을 구명하기 위해, 현장 및 해색 위성 자료를 활용하여 겨울철 표층 수온, 산란 적합 서식지(Suitable Spawning Habitat, SSH) 및 지속 면적(Consistently formed Suitable Spawning Habitat, CSSH), 봄철 chlorophyll-a (chl-a) 농도의 장기 변동성(2000-2024년)을 분석하였다. 연구 결과, Period B (2005-2009년), C (2010-2016년)에는 모두 CSSH 중심과 높은 chl-a 농도가 공간적으로 일치하여 초기 좋은 먹이 환경이 형성되었으며, 특히 Period C에는 SSH 면적의 급격한 증가가 어획량 상승에 주요하게 작용하였다. Period D (2017-2024년)에는 겨울철 수온이 평년 대비 0.6 ºC 높게 나타났으며, CSSH의 중심부가 북상 하고 SSH는 Period C 대비 면적이 약 34% 감소하였다. 동시에, 봄철 chl-a의 고농도 지역과 CSSH의 중심부와 공간적인 불일치(mismatch)가 발생하였다. 종합적으로, 도루묵 자원량의 급격한 변동은 산란장 면적과 위치, 지속성, 먹이원의 공간적 일치 여부 등 복합적 환경요인에 의해 결정되는 것으로 확인되었다. 특히 최근의 급격한 자원량 감소는 수온 상승으로 인한 산란장 축소와 산란장 중심부에서의 먹이원 부족으로 인한 초기 생존율 저하가 주요 원인으로 판단된다. 본 연구 결과는 도루묵 자원의 지속가능한 이용과 효율적인 관리를 위한 과 학적 기초자료로 활용될 것으로 기대된다.

According to the recently revised seismic design standards, seismic design of underground structures is required. Concrete underground outer walls are installed separately from temporary earth retaining walls as permanent underground outer walls. This raises issues of constructability, economy, and space narrowness. Therefore, a steel underground continuous wall is developed to promote construction efficiency, safety, and economy by introducing the off-site construction (OSC) method of underground structures. The steel underground continuous wall will be used as a permanent underground continuous wall along with the temporary earth retaining wall. To this end, it must satisfy structural performance equivalent to or higher than the concrete underground outer wall. The integrity and in-plane shear resistance performance between single panel members must be satisfied to be used as a permanent wall. The interlocking effect through geometric bonding is intended to enhance the bonding effect between these members. Therefore, trapezoidal members were developed, and bending performance tests and analyses of each member were performed to confirm the structural bending performance of these members. The bending performance improvement effect of the combined multiple members was confirmed. As a result, it was confirmed that the integration of members and structural performance was improved due to the interlocking effect of the absence of joints. The seismic design analysis of the demonstration site was performed with these developed members, and it was confirmed that the structural performance was equivalent to or higher than that of the existing RC underground continuous wall. As a result, it was confirmed that the steel underground continuous wall can be used as a permanent underground wall together with the temporary earth retaining wall.

PURPOSES : The aim of this study is to investigate the enhancement of performance and the mix design method for asphalt mixtures utilizing ferronickel slag, an industrial by-product METHODS : To enhance the performance of FNS asphalt, waste tire powder (CR) was incorporated, and the characteristics of FNS asphalt aggregate, along with the impact of CR, were evaluated through the mix design process. RESULTS : CR is found to be suitable with a size of 30 mesh, and the optimal usage amount is determined to be 1±0.1% of the mixture weight, considering dense grade asphalt mixture. Volumetric design considering the swelling characteristics of CR is necessary, and a mixing design with a consistent tendency can be achieved only when an appropriate VMA is secured. CONCLUSIONS : The mix design for FNS-R asphalt mixture requires an increase of approximately 1% in VMA compared to conventional dense-graded asphalt mixtures to accommodate the swelling of CR. Additionally, FNS-R asphalt exhibits improved resistance to rutting comparable to modified asphalt and meets quality standards, including stripping resistance.

PURPOSES : Derive a road pavement design method using Geocells, aim to derive a road pavement design and construction method suitable for the characteristics of the Bangladesh region METHODS : To assess long-term performance during road construction in Southeast Asia using Geocells, field tests and numerical analysis are conducted to verify stability. RESULTS : A total of 12 displacement measurements were conducted during the field tests, confirming an average load of 15.75 kN and an average displacement of 0.542mm. Inverse analysis was performed to obtain the properties of Geocell combined with compacted soil. The numerical analysis results confirmed that the insertion of Geocell provides better stability compared to the case with only compacted soil. CONCLUSIONS : Based on field tests and numerical analysis, a road design plan suitable for the Southeast Asian environment was proposed. A preliminary test section was selected in the Comilla region of Bangladesh, and test construction has been completed. Subsequent evaluations of the structural performance by soil layer in the test construction area will be conducted to develop a Geocell road pavement method, taking into consideration the characteristics of the Bangladesh region.