This study numerically compares optimum solutions generated by element- and node-wise topology optimization designs for free vibration structures, where element-and node-wise denote the use of element and nodal densities as design parameters, respectively. For static problems optimal solution comparisons of the two types for topology optimization designs have already been introduced by the author and many other researchers, and the static structural design is very common. In dynamic topology optimization problems the objective is in general related to maximum Eigenfrequency optimization subject to a given material limit since structures with a high fundamental frequency tend to be reasonable stiff for static loads. Numerical applications topologically maximizing the first natural Eigenfrequency verify the difference of solutions between element-and node-wise topology optimum designs.

Steel plate shear walls (SPSWs) have been recognized as an effective seismic-force resisting systems due to their excellent strength and stiffness characteristics. The infill steel plate in a SPSW is constrained by a boundary frame consisting of vertical and horizontal structural members. The main purpose of this study was to investigate deformation modes and hysteretic characteristics of steel plate shear walls (SPSWs) to consider the effects of their aspect ratios and width-to-thicness ratios. The finite element model (FEM) was establish in order to simulate cyclic responses of SPSWs which have the two-side clamped boundary condition and made of conventional steel grade. The stress distribution obtained from the FEA results demonstrated that the principal stresses on steel plate with large thickness-to-width ratio were more uniformly distributed along its horizontal cross section due to the formation of multiple struts.

본 연구에서는 공기역학적 형상변화의 풍하중 저감 측면에서의 효율성을 평가하기 위해 평면의 모서리 부분이 개선된 고층 건물에 대해 사례연구 기반의 비탄성 내풍설계를 수행하였다. 비선형 시간이력해석을 통해 다양한 설계풍속 및 항복 후 강성에 대한 구조물의 응답을 산정하였으며, 최근 국내 설계기준(KDS 41)에 도입된 성능기반내풍설계 개념을 토대로 구조물의 성능을 평가하였다. 해석 결과 공기역학적 형상변화를 갖는 구조물의 경우나 성능기반내풍설계를 적용했을 경우(또는 모두에 해당할 경우) 공진성분을 줄 여 구조물의 응답이 크게 감소함을 확인하였다.

Recently, the demand for shape memory alloys in the biomedical industry is increasing. Nitinol alloy, which accounts for most of the shape memory alloy market, occupies most of the biomedical field. Nitinol for biomaterials requires a clean surface without sub-micron surface integrity and surface defects in order to be used more safely in a living body. Among them, new technologies such as polishing using MR fluid are being studied, but there is a disadvantage in that it takes a long time for processing due to a low material removal rate. In this study, material removal studies were conducted for effective polishing, and excellent polishing properties of MR fluid were confirmed.

본 연구에서는 너클 라인이 다수 존재하면서 안팎 형상이 비대칭으로 설계된 특이점을 갖는 쌍동선의 자항성능을 예측하기 위 해 CFD 해석을 수행하였고, 해석 기법에 따른 차이를 파악하기 위해 MRF(Moving Reference Frame) 기법과 SDM(Sliding Mesh) 기법을 적용하 였다. MRF 기법을 적용한 경우에는 time step당 프로펠러를 1˚ 회전시켰고, SDM 기법의 경우 10˚, 5˚, 1˚씩 회전시키며 각 기법별 예측된 자 항성능을 비교하였다. 자항점 추정을 위한 몇 가지 프로펠러 회전수에서의 해석 결과 중 프로펠러의 토크는 기법에 따른 차이가 거의 없었 지만 추력 및 선체가 받는 저항은 MRF 기법보다는 SDM 기법을 적용했을 때 더 낮게, SDM 기법의 time step당 프로펠러 회전각이 작을수 록 높게 계산되었다. 선형 내삽을 통해 추정된 자항점의 프로펠러 회전수, 추력, 토크와 실선 확장법을 사용해 추정된 실선의 전달동력, 반 류 계수, 추력 감소 계수 및 프로펠러 회전수도 동일한 경향을 보였으며, 대부분의 자항효율은 반대의 경향을 보였다. 프로펠러 후류의 경 우 MRF 기법을 적용했을 때 정확도가 떨어졌고, SDM 기법의 time step당 프로펠러 회전각에 따라 표현되는 후류의 차이는 거의 없었다.

The seismic separation joint is an important device that absorbs vibration displacement from earthquake shock and protects fire extinguishing pipes and various utility pipes. In this study, the mechanical behavior occurring in U-typed and V-typed seismic separation joint was analyzed according to the length of the bellows, the length of the elbow straight pipe, and the open angle. As a result, as the length of the bellows increased, the stress and natural frequency decreased. In addition, as the length of the elbow straight pipe increased, the stress tended to decrease in the case of forced displacement in the vertical direction. As the open angle increased, the stress in the case of forced displacement in the left and right directions increased.

The overseas small ship market is witnessing a trend towards research aimed at substituting Fiber Reinforced Plastics (FRP), which poses environmental concerns, with High-Density Polyethylene (HDPE) in the shipbuilding process. Given the low melting point and high coefficient of thermal expansion of HDPE, research on joint areas is essential. This study focuses on preliminary investigations into ensuring the integrity of joints in shipbuilding processes using HDPE materials. Utilizing the Hot Gas Extrusion Welding method, which is conducive to joining large structures such as ships, HDPE joints were conducted. The material properties were evaluated based on the ASTM D638-14 international standards. This research aims to provide fundamental knowledge on the joining process of HDPE through Hot Gas Extrusion Welding and offers guidance on ensuring the integrity of joints in shipbuilding.

Friction stir spot welding (FSSW) is a solid-state joining process and a rapidly growing dissimilar material welding technology for joining metallic alloys in the automotive industry. Welding tool shape and process conditions must be appropriately controlled to obtain high bonding characteristics. In this study, FSSW is performed on dissimilar materials AA5052-H32 aluminum alloy sheet and SPRC440 steel sheet, and the influence of the shape of joining tool and tool insertion depth during joining is investigated. A new intermetallic compound is produced at the aluminum and steel sheets joint. When the insertion depth of the tool is insufficient, the intermetallic compound between the two sheets did not form uniformly. As the insertion depth increased, the intermetallic compound layer become uniform and continuous. The joint specimen shows higher values of tensile shear load as the diameter and insertion depth of the tool increase. This shows that the uniform formation of the intermetallic compound strengthens the bonding force between the joining specimens and increases the tensile shear load.

본 연구는 구약성경 안에서 하나님의 선교를 논할 때 제한적이며, 특히 창조신학과 원역사 안에서는 거의 다루어지지 않는다는 문제의식 에서 출발하였다. 하나님의 선교라는 렌즈로 성경 전체를 바라볼 수 있어야 하나님의 선교는 성경적인 뒷받침을 얻을 것이다. 본 연구는 하나님의 선교는 하나님의 형상을 통해 사명을 위임받아 보내심을 받은 선교적 인간에 의해 그분을 계시하고 세상에 구속과 샬롬을 이루는 인간의 선교로 나타난다는 것을 주장한다. 즉 하나님의 선교 관점에서, 하나님의 형상에는 창조된 인간이 그분을 계시하고, 세상에 구속과 샬롬을 이루도록 고안된 특별한 기능이 포함되어 있으며, 이 기능을 통해 인간은 공동체가 교회의 본질을 회복하는 데 중요한 역할을 담당할 수 있다는 것이다. 이를 통하여 하나님의 선교가 이루어져야 하는 방향과 선교가 보내심을 넘어서 하나님을 계시하는 모든 행하심이 선교이고 그것은 세상에 대한 보호와 보존, 발전임을 주장할 것이다. 그래서 보내심의 선교의 의미를 더 풍부하게 만드는 것이 또한 이 연구의 목적이 된다.

The current study investigates the seismic performance of shear-dominant RC columns retrofitted with iron-based shape memory alloy (Fe SMA). Three RC columns with insufficient transverse reinforcement were designed and fabricated for lateral cyclic loading tests. Before testing, two specimens were externally confined with carbon fiber-reinforced polymer (CFRP) sheets and self-prestressed Fe SMA strips. The test results showed that both CFRP and Fe SMA performed well in preventing severe shear failure exhibited by the unretrofitted control specimen. Furthermore, the two retrofitted specimens showed ductile flexural responses up to the drift ratios of ±8%. In terms of damage control, however, the Fe SMA confinement was superior to CFRP confinement in that the spalling of concrete was much less and that the rupture of confinement did not occur.

Decarbonization plays an important role in future energy systems for establishing a zero-carbon society. Hydrogen is believed to be a promising energy source that can be converted, stored, and utilized efficiently, leading to a broad range of possibilities for future applications. Hydrogen can be stored in various forms, including compressed gas, liquid hydrogen, hydrides, adsorbed hydrogen. Among these, liquid hydrogen has high gravimetric and volumetric hydrogen densities. There are a lot of previous studies on thermal behavior of MLI and VCS and optimization insulation system, but research on the insulation performance by varying the head shape of the tank has not been conducted. In this study, thermal-structural coupled analysis was conducted on the insulation system with VCS positioned between two layers of MLI for a liquid hydrogen storage tank. The analysis considered dome shapes (torispherical, circle, ellipses), and heat flux and temperature were derived from thermal analysis to predict insulation performance. Maximum equivalent stress and deformation were calculated from the structural analysis, and the optimal dome shape was proposed.

The theoretical capacity of silicon-based anode materials is more than 10 times higher than the capacity of graphite, so silicon can be used as an alternative to graphite anode materials. However, silicon has a much higher contraction and expansion rate due to lithiation of the anode material during the charge and discharge processes, compared to graphite anode materials, resulting in the pulverization of silicon particles during repeated charge and discharge. To compensate for the above issues, there is a growing interest in SiOx materials with a silica or carbon coating to minimize the expansion of the silicon. In this study, spherical silica (SiO2) was synthesized using TEOS as a starting material for the fabrication of such SiOx through heating in a reduction atmosphere. SiOx powder was produced by adding PVA as a carbon source and inducing the reduction of silica by the carbothermal reduction method. The ratio of TEOS to distilled water, the stirring time, and the amount of PVA added were adjusted to induce size and morphology, resulting in uniform nanosized spherical silica particles. For the reduction of the spherical monodisperse silica particles, a nitrogen gas atmosphere mixed with 5 % hydrogen was applied, and oxygen atoms in the silica were selectively removed by the carbothermal reduction method. The produced SiOx powder was characterized by FE-SEM to examine the morphology and size changes of the particles, and XPS and FT-IR were used to examine the x value (O/Si ratio) of the synthesized SiOx.

This study reports an experimental and analytical exploration of concrete columns laterally confined with Fe-based shape-memory alloy (Fe-SMA) spirals. For performing experiments, Fe-SMA rebars with a 4% prestrain and diameter of 10 mm were fabricated and concrete columns with internal Fe-SMA spiral reinforcement were constructed with a diameter of 200 mm and height of 600 mm. An acrylic bar with an attached strain gauge was embedded in the center of the specimen to measure local strains. Experimental variables encompassed the Fe-SMA spiral reinforcement, spacing, and activation temperature. Uniaxial compression tests were conducted after applying active confinement to the concrete columns through electrical-resistance heating. Notably, as the Fe-SMA spiral spacing decreased, the local failure zone length and compressive fracture energy of the prepared specimens increased. Additionally, a model incorporating compressive fracture energy was proposed to predict the stress–strain behavior of the. This model, accounting for active and passive confinement effects, demonstrated accurate predictions for the experimental results of this study as well as for previously reported results.

중국계 미국인 여성 작가 탕팅팅의 데뷔작인 『여용사』는 중국을 배경으로 하며 풍부한 상상력과 간결하고 직설적인 문 체를 통해 미국 중국계 소녀들의 어린 시절과 주변 여성들의 삶을 묘사하였다. 동시에 중국 본토의 유령을 자유와 싸우는 여성 영웅의 모습과 융합하여 미국에서 사는 중국계들이 받고 있는 차별, 억압, 불안함, 빈곤한 삶의 현실을 보여주었다. 이 연구는 비교문학 형상학(imagology)의 시각에서 『여용사』가 묘사한 용자의 이미지를 분석하였다. 이 연구는 작품 속 다섯 명의 여용사 이미지에 대한 분석을 통해 여용사가 어떻게 중국 의 봉건적 가부장제의 속박과 억압에서 벗어나 미국 서방 주류 사회에서 중국계 여성에 대한 고정관념을 뒤엎고 중국계 여성 의 주체성을 다시 세운 것에 대해 밝혔다.

명리학의 중요고전인 ｢적천수｣는 명리연구가들에 의하여 다수의 주석서가 지어졌다. 명사｢예문지｣에 그 서목이 등장하는 것으로 보아 명대 또는 그 이전에 지어진 것으로 보인다. 간결한 시결의 형태였던 원문에 최초의 주석(｢ 원주｣)이 나타났고, 청대이후에 일군의 명리학자들이 주석서를 지었으니, 임 철초의 주석을 담은 적천수천미가 그중의 하나이다. 풍부한 설명과 사주의 예시를 담았던 임철초의 주석은 근현대의 명리연구가들이 적천수를 이해하 는데 지대한 공헌을 했다. 그러나 임철초의 주석에서 일부의 용어의 개념이 혼란하여 사용된 정황이 있 었다. 본 논제인 적천수천미의 ｢형상｣장에서 주요하게 등장하는 용어가 ｢형 상｣장이외의 용례와는 다르게 활용되고 있음을 발견하였다. 논자는 여타의 곳에서 사용된 그 용어의 용례를 기반으로 하여 논란의 ｢형상｣장의 용어개념 을 새로이 정의하여 재해석하였다. 결과적으로 재해석한 내용을 기반으로 하 였을 때 임철초주석의 내용이 전체적으로 소통하여 일관성을 확보할 수 있었 으며, ｢형상｣장의 원문의 의미를 되살릴 수 있었다. 아울러 명리학자들이 주지하다시피 명리학의 고전을 연구하는데 고전과 고전 또는 이론과 이론 사이에 상호 교차하여 점검해보는 방식은 중요한 문 헌연구방법의 하나일 것이다. 이와 같은 연구방법으로 하여 재해석하였을 때 적천수내부의 이론적 맥락에서 일관성을 유지할 수 있었고 나아가 여타 명 리학고전과도 학론을 상통할 수 있었다. 본 연구 발표가 명리연구가들에게 고 전을 바라보는 안목과 해석하는 관점을 고양시키는데 보탬이 되었으면 한다. 주제어: 명리학, 적천수, 형상, 형상론, 화신, 화상, 화기, 양신성상.

In this study, a prefabricated buckling brace (PF-BRB) was proposed, and a test specimen was manufactured based on the design formula for the initial shape and structural performance tests were performed. As a result of the experiment, all standard performance requirements presented by KDS 41 17 00 and MOE 2021 were satisfied before and after replacement of the reinforcement module, and no fracture of the joint module occurred. As a result of the incremental load test, the physical properties showed a significant difference in the stiffness ratio after yielding under the compressive load of the envelope according to the experimental results. It is judged necessary to further analyze the physical properties according to the experimental results through finite element analysis in the future.

In this study, the seismic response characteristics of the three analysis model with or without TMD were investigated to find out the effective dome shape. The three analysis models are rib type, lattice type and geodesic type dome structure composed of space frame. The maximum vertical and horizontal displacements were evaluated at 1/4 point of the span by applying the resonance harmonic load and historical earthquake loads (El Centro, Kobe, Northridge earthquakes). The study of the effective TMD installation position for the dome structure shows that seismic response control was effective when eight TMDs were installed in all types of analysis model. The investigation of the efficiency of TMD according to dome shape presents that lattice dome and geodesic dome show excellent control performance, while rib dome shows different control performance depending on the historical seismic loads. Therefore, lattice and geodesic types are desirable for seismic response reduction using TMD compared to rib type.

The aging fishery training vessels from the past have mostly been decommissioned, and many universities are introducing state-of-the-art large fishery training vessels. The purpose of these training vessels is to train marine professionals and above all, safety to prevent marine accidents should be of utmost priority as many students embark on the vessel. This study estimated the impact of the hydrodynamic interaction forces acting on the model vessel (fishery training vessel) from the bank when the vessel pass near the semi-circle bank wall in various conditions through the numerical calculation, especially concerning maneuvering motions of the vessel. For estimation, variables were mainly set as the size of the semi-circle shape, the lateral distance between the bank and the model vessel, and the depth near the bank. As a result, it was estimated that, in order for the model vessel to safely pass the semi-circle bank wall at a speed of 4 knots, the water depth to the vessel draft ratio should be 1.5 or more (approximately 8 m of water depth), and the lateral distance from the semi-circle bank wall should be 0.4 times the model vessel’s length    or more (a distance of 34 m or more). Under these conditions, it was expected that the model vessel would pass without significantly being affected by the bank wall.