In this paper, the changes of the uniaxial tensile mechanical properties of the ETFE film after the uniaxial pre-stretching stress exceeds the first yield stress and the second yield stress was investigated. The ETFE film is first pre-stretched uniaxially along the MD direction or TD direction. After the pre-stretching loading stress exceeds the first yield stress and the second yield stress to cause the ETFE film to undergo plastic deformation, rectangular uniaxial tensile specimens are cut from the pre-stretched film along the MD direction and the TD direction for subsequent uniaxial tensile tests, thereby determining the uniaxial tensile mechanical property parameters of the ETFE film after uniaxial pre-stretching, including yield stress, tensile strength and elongation at break, and discussing the changes in its uniaxial tensile mechanical properties.

This study investigated benthic macroinvertebrates and fish in the Yeongsangang River weir and analyzed stomach contents of Squalidus chankaensis tsuchigae. Length distribution of individuals varied by site, with 91.3% and 72.7% falling within the 70-90 mm range in SC-U (upstream location of Seungchon weir) and SJ (location between Seungchon and Juksan weirs), respectively, and 77.5% within 70-80 mm and 100 mm range in JS-D (downstream location of Juksan weir). Chironomidae spp. (nonred type) were the most abundant food sources, comprising 46.3%, 76.9%, and 88.3% of the diet at SC-U, SJ, and JS-D, respectively. The Electivity Index (EI) indicated a strong preference for Chironomidae spp. (non-red type) (0.927) and avoidance for the red type (-0.929) and Limnodrilus gotoi (-0.995). The proportion of burrowers (BU) increased downstream, while swimmers (SW) decreased. The condition factor (K) varied by site, decreasing in SC-U and increasing in SJ and JS-D, showing a significant positive influence on the number of food sources (p<0.05). Among food sources, Chironomidae spp. and Baetidae sp. were predicted to be utilized across a broad range of lengths and weights, with strong connectivity observed among Tanypodinae sp., Hymenoptera sp., and Baetiella tuberculata.

도로 분야에서 참고되는 기준은 국토교통부령에 따른 도로의 구조·시설 기준에 관한 규칙과 행정규칙의 위계를 갖는 건설 기준이 존 재한다. 앞서 언급한 규칙과 기준은 법적인 근거를 바탕으로 상위기술기준으로 구분되고, 이 외에 소관부서에서 사회 현안 해결 등으 로 필요에 따라 지침, 편람, 가이드 라인 등의 형태로 배포 또는 고시되는 간행물이 하위기술기준으로 구분된다. 일반적으로 상위기술 기준은 정해진 절차에 따라 유지·관리 및 개정 등이 이루어지지만, 하위기술기준은 소관부서에서 관리되고 있기 때문에 지속적인 관리 에 한계점이 존재한다. 도로 분야 하위기술기준에 대한 선행 연구에서는 현재까지 150여 개의 다양한 안건으로 하위기술기준이 배포 되었으며, 이 중 존치가 필요한 하위기술기준과 폐지가 되어야 할 하위기술기준을 검토하여 도로 분야 하위기술기준에 대한 관리의 필요성에 대하여 제시한 바 있다. 본 연구에서는 도로 분야 하위기술기준의 지속적인 유지 및 관리를 위한 방안을 마련하기 위하여 현행 건설 기준과 연계한 기술 지침(KDSG/KCSG)의 도입 필요성을 제안하고, 이를 바탕으로 존치가 필요한 하위기술기준을 기술 지침 으로 도입할 수 있는 연계 방안을 검토하였다.

In this paper, several types of torque distribution functions (TDFs) are presented for the instantaneous torque control of switched reluctance motor (SRM) drives. To verify the feasibility and effectiveness of the proposed TDFs, two different categories—parameter non-adaptive and parameter adaptive functions—are introduced and analyzed. These different types of TDFs are systematically implemented in instantaneous torque control schemes to enhance the performance of SRM drives. The proposed torque control method, incorporating these various TDFs, is modeled and simulated in PSIM software to validate the presented control schemes. Simulation results demonstrate the effectiveness of the proposed approach in achieving precise torque control and improving the dynamic performance of SRM drives.

As global greenhouse gas reduction regulations are strengthened and the demand for eco-friendly energy increases, renewable energies, including offshore wind power, are growing rapidly. Unlike onshore wind power generation, offshore wind power is located in the ocean. As a result, the offshore wind power substructure is exposed to low temperatures, corrosion, and continuous fatigue loads. Therefore, selecting appropriate materials and welding techniques is crucial for durability. In this study, FCAW welding was performed on S355ML steel (EN10025) for offshore wind power applications. After the welding process, the mechanical properties of the welded joint were evaluated through tensile, low-temperature impact, and hardness tests to assess the welding condition. The study revealed that the tensile and yield strength of the welded joint were superior to those of the base material. Additionally, the impact strength at low temperatures was confirmed to exceed the standard.

This study aimed to identify the selectivity of catches according to mesh size of gillnets, and to collect basic data for fisheries resource management plans for gillnets. The mesh selectivity test was conducted with five different mesh sizes (60, 66, 69, 75, and 96 mm) gillnet in coastal sea of Mukho port and the selectivity was analyzed using the Kitahara method. In results of the selectivity test, a total of 143 (36,249 g) of atka mackerel were caught and the 60 mm gillnet was the highest at 83 (18,596 g), which is about 58.0% of the total catch. The relative growth equation between body length and weight showed that weight tends to increase proportional to body length. The maximum length/mesh size value was showed 0.490 by the master curve of selectivity, and the 50% selection range was showed 0.138. Therefore, it was found that the size of the caught fish increased proportional to the mesh size. The results of this study were intended to be used as data for establishing a plan for efficient management of atka mackerel resources.

Being in a stable continental region (SCR) with a limited history of instrumentation, South Korea has not collected sufficient instrumental data for data-driven ground motion models. To address this limitation, we investigated the suitability of the hybrid ground motion simulation method that Graves and Pitarka (2010, 2015) proposed for simulating earthquake ground motions in South Korea. The hybrid ground motion simulation method used in this study relies on region-specific parameters to accurately model phenomena associated with the seismic source and the wave propagation. We initially employed relevant models and parameters available in the literature as a practical approach. We incorporated a three-dimensional velocity model developed by Kim et al. (2017) and a one-dimensional velocity model presented by Kim et al. (2011) to account for the crustal velocity structure of the Korean peninsula. To represent the earthquake source, we utilized Graves and Pitarka’s rupture generator algorithm along with a magnitude-area scaling relationship developed for SCR by Leonard (2014). Additionally, we assumed the stress and attenuation parameters based on studies of regional seismicity. Using the implemented platform, we simulated the 2016 Mw5.57 Gyeongju earthquake and the 2017 Mw5.4 Pohang earthquake. Subsequently, we compared results with recorded accelerations and an empirical ground motion prediction equation at strong motion stations. Our simulations had an overall satisfactory agreement with the recorded ground motions and demonstrated the potential of broadband hybrid ground motion simulation for engineering applications in South Korea. However, limitations remain, such as the underestimation of long-period ground motions during the 2017 Pohang earthquake and the lack of a model to predict the ground motion amplification associated with the near-surface site response accurately. These limitations underscore the importance of careful validation and refinement of region-specific models and parameters for practically implementing the simulation method.

In stable continental regions, selecting appropriate ground motions for seismic design and dynamic response analysis presents significant challenges. This study evaluates the liquefaction potential of the Nakdonggang delta region, South Korea, by generating synthetic ground motion scenarios and applying a scenario-based liquefaction assessment approach. We utilized a hybrid broadband ground motion simulation method proposed by Graves and Pitarka (2010, 2015) to create bedrock ground motions for three hypothetical earthquakes (Mw 6.2 and 6.0) occurring along the Dongrae and Miryang faults. The generated synthetic ground motions were used as input for onedimensional nonlinear site response analyses, incorporating shear wave velocity profiles derived from surface wave inversion. The simulated ground motions demonstrated higher responses at short periods and relatively weaker responses at long periods compared to the Korean design spectra. This amplification of long-period components was attributed to the dynamic response of deep sedimentary layers, while high-frequency components were generally deamplified due to damping effects in shallow silty layers. Liquefaction susceptibility was assessed using surface ground motions derived from the site response analyses, following the SPT-based simplified method proposed by Idriss and Boulanger (2008). Results indicated high liquefaction potential across most sites for the Dongrae earthquake scenario, while liquefaction was unlikely for all sites under the Miryang-1 scenario. For the Miryang-2 scenario, liquefaction was predicted at some sites. Overall, liquefaction is expected at PGA values of approximately 0.13 g or higher, with sites exhibiting lower shear wave velocities being more vulnerable to liquefaction

본 연구는 외국인 근로자의 심리사회적 근로환경이 심리적 웰빙과 직무열의에 미치는 영향을 파악하기 위해 수행되었다. 연구대상은 제6차 근로환경조사에 포함된 외국인 근로자 221명이다. 자료 분석 은 가중치가 적용된 복합표본분석 중 일반선형모형분석을 통해 이루어졌다. 연구결과 외국인 근로자의 심 리적 웰빙과 직무열의에 동료의 사회적 지지와 적절한 보상이 유의한 영향요인으로 확인되었다. 상사의 사 회적지지, 직업 불안정성, 합당한 업무인정, 업무에 의견반영 등의 심리사회적 근로환경요인은 유의하지 않 았다. 결론적으로 외국인 근로자들의 동료의 사회적 지지와 적절한 보상은 심리적 웰빙과 직무열의를 증진 하기 위한 심리사회적 근로환경 개선 대책에서 중요하게 다루어져야 할 것이다.

전 세계적으로 기후변화 등의 환경 문제와 자원고갈 문제가 심각해짐에 따라 화석연료의 의존 도를 낮추고 탄소중립을 실현할 수 있는 대체 에너지원 확보가 중요해졌다. 이에 따라 국내 발전분야에서 는 중유를 대체할 수 있는 폐자원 유래 바이오중유를 2014년부터 시범보급하여 2019년 상용화를 시작하였 다. 본 연구에서는 2014년 시범보급 시작부터 2023년까지 상용화 기간을 포함한 10년간 국내에서 발전용 연료로 사용된 바이오중유를 대상으로 원료 수급 데이터 및 연료 품질 모니터링 데이터를 연도별로 분석하 여 주요 품질 특성의 변화를 평가하였다. 시범보급 초기에는 저가 원료의 사용 및 연료 제조기술의 부족 등으로 인화점, 동점도, 황분, 회분, 전산가, 금속분, 질소분, 인함량 등 대부분 품질 항목의 변동성이 컸으 나, 2018년까지 시범보급 기간을 거치며 바이오중유 생산사들의 제조기술 및 발전소의 구매 연료 품질 관 리 체계의 발전 등으로 연료 품질이 빠르게 안정화되었다. 이후 상용화 기간을 포함한 2023년까지 인화점 과 황분 함량은 안정적으로 유지되었고, 동점도, 회분, 유동점, 전산가, 금속분, 인 함량 등은 감소 추세를 나타내었으며, 발열량은 증가 추세를 보이는 것으로 나타났다. 10년간 바이오중유의 품질은 시범보급 첫해 를 제외하고 모두 법적인 품질기준을 만족하였고 연료로서의 품질 특성은 안정화되며 개선되고 있는 것으 로 나타났다.

The International Maritime Organization (IMO) is promoting the transition to eco-friendly fuels such as hydrogen and ammonia, with the goal of achieving net-zero greenhouse gas emissions in the shipping sector by 2050. Hydrogen does not emit greenhouse gases, but it must be stored at an extremely low temperature of -253°C when stored as a liquid. 316L stainless steel is mainly used as a tank material to store liquid hydrogen. FCAW (Flux Cored Arc Welding) is known for its excellent weldability with 316L stainless steel, and it is particularly suited for welding thick metals efficiently, making it an ideal choice for storage tank welding. Finite Element Method (FEM) analysis can simulate the thermal and mechanical deformations occurring during welding with high precision, allowing for accurate prediction of deformation patterns and the derivation of optimal welding conditions. This ensures the stability and quality of the structure while reducing costs. In this study, FCAW butt welding was performed on 316L stainless steel, followed by cross-sectional observation and deformation measurement of the weld area. Based on the cross-sectional observation, a 3D FE model was designed, and heat transfer analysis was conducted. Subsequently, thermo-mechanical analysis was carried out to predict welding deformation.

전세계적으로 국제항공 부문의 탄소 감축에 대한 요구가 증가함에 따라 지속가능항공유 (Sustainable Aviation Fuel, SAF)의 사용 확대와 기술개발에 대한 투자가 촉진되고 있다. SAF는 기존 석유 계 항공유 연료와 유사하기 때문에 항공기의 엔진이나 연료 공급 시스템 및 공항의 연료공급 인프라의 구 조적 변경없이 그대로 사용 가능하며(drop-in fuel), 기존 항공유에 일정비율로 혼합하여 사용할 수 있는 장점이 있다. SAF는 전세계적으로 다양한 바이오매스 원료를 사용하여 제조된 바이오항공유(Bio-jet fuel) 와 포집 이산화탄소와 그린수를 사용하여 합성된 재생합성항공유(synthetic-SAF)로 구분할 수 있다. 또한 광합성을 하는 바이오매스를 기반으로 하는 바이오항공유는 전주기평가(life cycle assessment, LCA) 관점 에서 기존 석유계 항공유보다 이산화탄소를 약 80% 저감되며, 탄소중립연료로서 인정받고 있다. 본 논문 에서는 재생합성항공유의 생산을 위한 제조기술로 이산화탄소 포집기술, 역수성가스(Reverse Water-Gas Shift, RWGS) 전환기술, Fischer-Tropsch(F-T) 공정기술과 제조된 재생합성항공유의 연료특성과 제조규 격 및 제조기술 인증에 대한 연구사례를 분석하여 국내 기술개발 필요성과 방향을 제시하고자 한다.

Magnesium alloys, among various non-ferrous metals, are utilized in diverse fields from the automotive industry to aerospace due to their light weight and excellent specific strength. In the previous Part I study, fiber laser BOP experiments were conducted to derive basic welding characteristics and appropriate bu竹 welding conditions. Subsequently, in the Part II experiment, butt welding was performed, and through tensile tests, hardness tests, and cross-sectional observations, it was found that at laser power of 2.0 kW and welding speed of 50 mm/s, 93% of the base metafs tensile strength and 63.4% of its elongation could be achieved. In this Part III experiment, the microstructures of the base metal and the center of the weld were observed in butt-welded specimens. Through this, laser power and welding speed, on the mechanical behavior and microstructure of magnesium alloys were analyzed

In 2013, Imsil Pilbong Culture Village installed a dome-shaped membrane structure off a ceiling of an outdoor performance hall in order to support performances under bad climate condition. However, sound energy during the performance is collected under the dome structure and bounced back to the stage, which produces mixed acoustic which causes a serious acoustic defects. So, in this study, in order to improve the acoustical performance of the outdoor performance hall in Korea Soriter, two sound performance improvements were proposed using sound simulation according to the installation suspension absorbers after identifying acoustic defects through field measurement. The results of study, the comparison between sound performance improvement test, sound pressure level (SPL500Hz) was 64.7dB at 69.0dB, the weighted sound level (SPLdB(A)) was 68.8dB(A) at 78.7dB(A), reverberation time (RT500Hz) was 1.28sec at 2.19sec, early decay time (EDT500Hz) was 1.48sec at 2.41 sec, definition (D50,500Hz) was 52.9% at 29.8%, clarity (C80.500Hz) was 2.2dB at -l.OdB, and RASTI was 584.4%(“Fair”) at 51.1%(“Fair”) was evaluated.

The present study was undertaken to ascertain the temperature development characteristics of Phthorimaea operculella (Lepidoptera: Gelechiidae) across its various developmental stages. To this end, the insect was subjected to six constant temperature conditions (13, 17, 25, 27, 32, 34±1°C), relative humidity (RH) levels of 65±5%, and photoperiods of 16 : 8 h light/dark. The developmental time of larvae was longest at 13°C, and as the temperature increased up to 35°C, the developmental time tended to become shorter. At the pupal stage, all individuals developing at 13°C perished and were excluded from the calculation of the development period for the development model. To ascertain the relationship between temperature and development, a regression model was employed for analysis. The lower threshold temperature of the total immature stage was determined to be 9.4°C, and the thermal constant was found to be 454.5DD. In the analysis of the temperature-development experiment, the Lactin 2 model exhibited an optimal fit (R 2=0.90-0.98) for the total immature stage of P. operculella.

본 연구에서는 열유도상분리법으로 제조한 polyvinylidene fluoride (PVDF) 중공사막의 오염성과 화학적 세척에 대한 실험을 진행하였다. 오염수는 소 혈청 단백질(bovine serum albumin, BSA)과 카올린(kaolin)을 이용해 제조하였으며, 차아 염소산나트륨(NaOCl), 구연산(citric acid), 황산(H2SO4)으로 화학적 세척을 진행한 후 뒤 표면 전하 분석기, 주사전자현미경 (scanning electron microscope, SEM) 그리고 에너지 분산 X선 분광법(energy dispersive X-ray spectroscopy, EDX)을 통해 세 척 효율을 평가하였다. PVDF 분리막은 높은 내화학성과 열적 안정성을 가지는 분리막으로 화학적 세척을 진행한 결과 가장 좋은 효율은 차아염소산나트륨으로 세척한 것으로 그 결과 투과도는 793.2 L/(m2.h.bar)로 초기 투과량인 945.3 L/(m2.h.bar) 값과 비교하였을 때 약 84% 회복률을 보여주었다. 이는 수처리 공정에서의 막 오염 방지 및 세척의 중요성을 제시한다.

The focus of this study was on the preparation of a clinoptilolite-based adsorbent, utilizing natural zeolite, to adsorb and remove ammonia (NH3) emitted from various environmental facilities, and to evaluate its performance. To create an adsorbent suitable for humid environments, hydrophobicity was introduced through HCl acid treatment. The impact of acid concentration and treatment time was analyzed to optimize the preparation conditions. As a result, the adsorbent treated with 0.5 M HCl for 2 hours demonstrated the highest NH3 adsorption performance. These findings suggest that the developed adsorbent could serve as an effective solution for controlling NH3 emissions in humid environments, contributing to the mitigation of environmental pollution and odor issues.

This study proposes a steel plate retrofit method and a polyurea method to improve the structural stability and usability of a factory floor slab with a thickness of 120mm. To assess vibration changes, vibrations were measured before and after retrofit. A numerical analysis model was also developed to evaluate improvements in structural safety and usability. The natural frequency increased from 11.4Hz to 17Hz through steel plate reinforcement, confirming an increase in slab stiffness. The damping ratio increased from 2.3% to 3.2% with polyurea reinforcement, indicating improved vibration reduction. Additionally, numerical analysis modeling showed that the natural frequency increased from 13.9Hz to 16.2Hz due to the steel plate reinforcement, enhancing the dynamic characteristics of the floor slab and confirming the reliability of the analysis model.

이 연구에서는 교수요목기부터 7차 교육과정에 이르기까지 초등사회과 교육과정에 나타난 금융교육 내용 요소를 분석한다. 분석 결과를 요약하면 다음과 같다. 첫째, 우리나라 초기의 교육과정에서 금융교육 관련 내용은 대체로 은행이나 조합과 같은 금융기관에 대한 이해와 절약 및 저축에 대한 강조가 주를 이루었다. 둘째, 이후 교육과정이 개정을 거듭하는 과정에 서 금융기관에 대한 이해와 절약에 대한 강조는 점차 줄어들었으며, 가정의 수입과 지출에 대한 이해와 이에 바탕을 둔 현명한 소비와 같은 가계의 재무관리 측면이 부각되는 경향을 보였다. 셋째, 교육과정이 여러 변화를 거듭하는 과정에서도 저축에 대한 강조는 약화되지 않았다. 넷째, 보험, 예금, IMF 등과 같이 일회적으로 등장했다가 사라진 금융교육 내용 요소가 있다.