Environmental pollution has led to global warming, which threatens human life. In response, hydrogen is gaining attention as a next-generation energy source that does not emit carbon. Due to its explosive nature, special care must be taken in the safe storage and transportation of hydrogen. Among various storage methods, liquefied storage, which can reduce its volume to 1/800, is considered efficient. However, since its boiling point reaches -253°C, the design of an insulation system is essential. For the design of insulation systems applied to large containers, a membrane-type design is required, which necessitates the use of cryogenic adhesives. To evaluate whether the cryogenic adhesive is properly implemented, assessments such as tensile and shear tests are necessary. This study presents a methodology for shear evaluation. Conventional methods for shear evaluation of adhesives result in slippage, preventing proper assessment. Therefore, a method involving drilling holes in the gripper and pulling from the holes must be applied. Optimal design concerning the size and location of the holes is required, and this study derives optimal values based on finite element analysis. By conducting experiments based on the results of this study, it is expected that the risk of gripper damage will be minimized, allowing for accurate evaluation of the adhesive’s performance.

In this study, the relationship between the color of the pigment added to the plastic resin and the size of the fractured part of the specimen was confirmed when processing ABS plastic tensile specimens using a sealed 3D printer. Through the test, it was confirmed that the fracture dimension existed in the range of 13.104 to 13.138 ㎜ and there was no significant difference in dimension according to the color of the additive, and the null hypothesis was adopted. In addition, it was confirmed that a significant difference occurred in the order of red, black, white, and green colors.

PURPOSES : Pavement surface friction depends significantly on pavement surface texture characteristics. The mean texture depth (MTD), which is an index representing pavement surface texture characteristics, is typically used to predict pavement surface friction. However, the MTD may not be sufficient to represent the texture characteristics to predict friction. To enhance the prediction of pavement surface friction, one must select additional variables that can explain complex pavement surface textures. METHODS : In this study, pavement surface texture characteristics that affect pavement surface friction were analyzed based on the friction mechanism. The wavelength, pavement surface texture shape, and pavement texture depth were hypothesized to significantly affect the surface friction of pavement. To verify this, the effects of the three abovementioned pavement surface texture characteristics on pavement surface friction must be investigated. However, because the surface texture of actual pavements is irregular, examining the individual effects of these characteristics is difficult. To achieve this goal, the selected pavement surface texture characteristics were formed quantitatively, and the irregularities of the actual pavement surface texture were improved by artificially forming the pavement surface texture using threedimensionally printed specimens. To reflect the pavement surface texture characteristics in the specimen, the MTD was set as the pavement surface texture depth, and the exposed aggregate number (EAN) was set as a variable. Additionally, the aggregate shape was controlled to reflect the characteristics of the pavement surface texture of the specimen. Subsequently, a shape index was proposed and implemented in a statistical analysis to investigate its effect on pavement friction. The pavement surface friction was measured via the British pendulum test, which enables measurement to be performed in narrow areas, considering the limited size of the three-dimensionally printed specimens. On wet pavement surfaces, the pavement surface friction reduced significantly because of the water film, which intensified the effect of the pavement surface texture. Therefore, the pavement surface friction was measured under wet conditions. Accordingly, a BPN (wet) prediction model was proposed by statistically analyzing the relationship among the MTD, EAN, aggregate shape, and BPN (wet). RESULTS : Pavement surface friction is affected by adhesion and hysteresis, with hysteresis being the predominant factor under wet conditions. Because hysteresis is caused by the deformation of rubber, pavement surface friction can be secured through the formation of a pavement surface texture that causes rubber deformation. Hysteresis occurs through the function of macro-textures among pavement surface textures, and the effects of macro-texture factors such as the EAN, MTD, and aggregate shape on the BPN (wet) are as follows: 1) The MTD ranges set in this study are 0.8, 1.0, and 1.2, and under the experimental conditions, the BPN (wet) increases linearly with the MTD. 2) An optimum EAN is indicated when the BPN (wet) is the maximum, and the BPN decreases after its maximum value is attained. This may be because when the EAN increases excessively, the space for the rubber to penetrate decreases, thereby reducing the hysteresis. 3) The shape of the aggregate is closely related to the EAN; meanwhile, the maximum value of the pavement surface friction and the optimum EAN change depending on the aggregate shape. This is believed to be due to changes in the rubber penetration volume based on the aggregate shape. Based on the results above, a statistical prediction model for the BPN (wet) is proposed using the MTD, EAN, and shape index as variables. CONCLUSIONS : The EAN, MTD, and aggregate shape are crucial factors in predicting skid resistance. Notably, the EAN and aggregate shape, which are not incorporated into existing pavement surface friction prediction models, affect the pavement surface friction. However, the texture of the specimen created via three-dimensional printing differs significantly from the actual pavement surface texture. Therefore, the pavement surface friction prediction model proposed in this study should be supplemented with comparisons with actual pavement surface data in the future.

Scanning probe microscopy (SPM) has become an indispensable tool in efforts to develop the next generation of nanoelectronic devices, given its achievable nanometer spatial resolution and highly versatile ability to measure a variety of properties. Recently a new scanning probe microscope was developed to overcome the tip degradation problem of the classic SPM. The main advantage of this new method, called Reverse tip sample (RTS) SPM, is that a single tip can be replaced by a chip containing hundreds to thousands of tips. Generally for use in RTS SPM, pyramid-shaped diamond tips are made by molding on a silicon substrate. Combining RTS SPM with Scanning spreading resistance microscopy (SSRM) using the diamond tip offers the potential to perform 3D profiling of semiconductor materials. However, damage frequently occurs to the completed tips because of the complex manufacturing process. In this work, we design, fabricate, and evaluate an RTS tip chip prototype to simplify the complex manufacturing process, prevent tip damage, and shorten manufacturing time.

이 논문은 결정론적인 역사적 순환에서 인간이 개입하고 참여할 수 있는 여러 방식을 세 편의 수태고지 시를 중심으로 다시 읽는다. 예이츠의 역사 체계에서 역사 순환은 단순히 인간의 외부에서 부과되는 것뿐만 아니라 인간의 여러 잠재력과의 상호작용을 통해 진행한다. ｢레다와 백조｣는 그리스 문명의 탄생이 레다라는 인간의 실존과 몸을 통해 매개됨을 보여준다. ｢한 희곡 작품에서 발췌한 두 편의 노래｣는 인간의 자유가 실패에도 불구하고 압도적인 역사 순환의 힘에 저항하는 것에서 표출됨을 드러낸다. ｢재림｣은 역사 순환이 역사에 대한 사실 그 자체가 역사의 사실이 되는 것이 아니라 인간의 관점과 문제의식에 따라 해석하여 재구성된다는 예이츠의 확신에 맞닿아 있다. 세 편의 수태고지 시에서 예이츠는 역사의 순환과 인간의 잠재력—몸, 실존, 자유의지, 해석 등—사이의 대립을 화해로 전환하는데, 이는 역사의 순환을 재배열하고 의미를 부여하려는 인간의 투쟁으로 매개된다.

The influence of specimen geometry and notch on the hydrogen embrittlement of an SA372 steel for pressure vessels was investigated in this study. A slow strain-rate tensile (SSRT) test after the electrochemical hydrogen charging method was conducted on four types of tensile specimens with different directions, shapes (plate, round), and notches. The plate-type specimen showed a significant decrease in hydrogen embrittlement resistance owing to its large surface-to-volume ratio, compared to the round-type specimen. It is well established that most of the hydrogen distributes over the specimen surface when it is electrochemically charged. For the round-type specimens, the notched specimen showed increased hydrogen susceptibility compared with the unnotched one. A notch causes stress concentration and thus generates lots of dislocations in the locally deformed regions during the SSRT test. The solute hydrogen weakens the interactions between these dislocations by promoting the shielding effect of stress fields, which is called hydrogen-enhanced localized plasticity mechanisms. These results provide crucial insights into the relationship between specimen geometry and hydrogen embrittlement resistance.

This study aims to examine the correlation between microstructures and the mechanical properties of two highstrength API X70 linepipe steels with different specimen directions and Moaddition. The microstructure of the Mo-added steel has an irregularly shaped AF, GB matrix with pearlite because of the relatively large deformation in the non-recrystallization temperature region, while that of the Mo-free steel shows a PF matrix with bainitic microstructure. In the Mo-added steel, the M/A (martensite-austenite) in granular bainite (GB) and pearlite act as crack initiation sites with decreased upper shelf energy and an increased ductile to brittle transition temperature (DBTT). Regardless of Mo addition, all of the steels demonstrate higher strength and lower elongation in the T direction than in the L direction because of the short dislocation glide path and ease of pile-up at grain boundaries. In addition, the impact test specimens with T-L direction had a lower impact absorbed energy and higher DBTT than those with the L-T direction because the former exhibit shorter unit crack path compared to the latter.

In this study, measurement errors of the X and Y axes were verified by using an 80-100 mm gauge block, an NPL type angle measuring device, and a spelling on a contact-type 3D measuring device surface plate. In addition, the measurement specimen was repeatedly measured 10 times at 10° intervals from 0° to 40° to confirm the average value and standard deviation. After confirming the statistical test value (P) through ANOVA analysis of the statistical program, the correlation between angle change and error was confirmed.

Recently 3d printer industry has two demands. first is color 3d printing. second is mass production using 3d printer that has large bed. According to previous studies, 3D printed objects have different weights depending on filament colors. 3D printed tensile specimens with filaments of various colors were checked to see they had the same weight. If so, we wanted to see it was statistically significant. As a result, we found that the weight of 3D printed objects was statistically significantly different depending on the filament color. The average weight of 3d printed objects is: Black(8.63g), Blue(8.58g), Yellow(8.53g), White(8.48g), Natural(8.46g), Green (8.45g), Red(8.42g).

선박에 부착된 수중생물은 선체에서 성장하면서 선박의 저항을 크게 증가시킬 뿐만 아니라 부착생물이 배와 함께 이동하면서 지역의 해양 생태계 교란을 야기시키기도 한다. 이에 따라 국제해사기구에서는 선체부착생물의 이동을 막기 위해 선체부착생물 제거 및 청소성능 평가 논의를 시작해 오고 있다. 본 연구에서는 소형선박에 사용되는 FRP(Fiber Reinforced Plastic), HDPE((High Density Polyethylene), CFRP(Carbon Fiber Reinforced Plastic) 재료의 시편을 격포항(전락북도)에 약 80일간 양생시킨 후 물 제트 노즐을 이용하여 부착생물 제거실 험을 수행하였다. 그 결과 김과 같은 해조류는 노즐과 시편과의 거리가 1.8cm, 100bar 일 때 제거되었지만, 따개비의 경우 200 bar 이상은 되어야 청소가 되는 것을 확인하였다.

본고는 오랫동안 비평적 무관심을 받아 온 존 밀턴의 가장 초기 시들, 즉 시편 114편과 136편의 운문 번역을 새롭게 조명하고자 한다. 이 운문 번역 시편들은 밀턴이 15세에 쓴 것으로 일반적으로 학자들은 이 작품들을 밀턴의 습작(習作) 이상으로 취급하지 않았다. 그러나 이 운문 번역이 쓰여진 1620년 초기의 역사적 상황을 고려한다면 밀턴의 시편 114편과 136편 번역은 지금까지보다 섬세한 독해를 요구한다. 본고는 밀턴의 초기 시편 번역이 단순한 습작이 아니라 모국어 운문 시편 번역 전통 안에서 밀턴 특유의 시적 자유와 시편의 전례(典禮) 전통을 개혁하고자 하는 의지가 담긴 시도라고 주장한다.

3D 프린팅은 다수의 레이어(layer)를 적층하여 물체를 제작하는 기법으로, 복잡한 형상을 가지는 물체를 비교적 쉽게 제작할 수 있 다. 이를 건설 산업에 접목한 3D 콘크리트 프린팅(3D concrete printing)은 콘크리트 타설 시 거푸집을 사용하지 않으며, 비교적 적은 작업량과 인력이 요구되므로 경제적인 시공이 가능하나, 출력된 3D 프린팅 콘크리트는 일반 콘크리트 대비 다소 낮은 강도가 예상된 다. 따라서, 본 연구에서는 3D 프린팅 콘크리트 시편의 물성을 분석하였다. 3D 프린팅 콘크리트 시편 출력을 위해 Ultimaker Cura 소 프트웨어로 형상 및 출력 경로를 설계하고, 이를 바탕으로 3D 프린터를 제어하는 G-code를 생성하였다. 연구에서 사용된 3D 프린터 의 출력 성능과 콘크리트의 적층성, 유동성 등을 고려하여 최적의 배합비를 선정하였고, 시편 출력에 활용하였다. 시편 출력 시 동일 한 치수를 가지는 몰드 시편을 함께 제작하여 비교･분석에 사용하였다. 각 시편의 물성은 휨강도 시험과 압축강도 시험을 통해 각각 의 강도를 측정하였고, 비교･분석하여 3D 프린팅 콘크리트 시편의 물성을 확인하였다.

In this study, using a 100mm gauge block in a contact-type three-dimensional measuring machine surface plate, an NPL-type angle measurement, and a steel ruler, the specimen was measured at 0°, 5°, 10°, 20°, 30°, and 40° along the X and Y axes. After setting the measurement conditions, the average value and standard deviation were confirmed by repeating measurements for each yield 10 times. After checking the statistical test value (P) through ANOVA, the correlation between the angle change and the error was checked.

예이츠에게 비잔티움은 충격 그 자체였다. 아폴로니아 성당의 모자이크 벽에서 만난 황금새는 금세공사가 만든 인공적인 예술작품이지만, 시간과 이미지를 초 월한 영원한 이상세계의 아름다움을 간직하고 있고 동시에 생성과 변화를 반복하는 현 실세계의 정화되지 않은 이미지들과 충돌하여 파괴하는 것으로 보았다. 예이츠는 비잔 티움으로의 항해 와 비잔티움 의 두 시를 통하여 현실세계와 이상세계와의 충돌을 넘 어 조화와 일치를 이루고자 무던히도 노력했음을 알 수 있다.

Fused Deposition Modeling (FDM), also known as Fused Deposition Modeling (FFF), is the most widely used type of 3D printing at the consumer level. The FDM 3D printer extracts thermoplastic filaments such as ABS (Acrylonitrile Butadiene Styrene) and Polyactive Acid (PLA) through heated nozzles to dissolve the material. It works by applying layers of plastic to build platforms. Various demands for 3D printers increased, and among these demands, there was also a demand for various filament colors. ABS, one of the main filamentous materials for 3D printers, is easy to color in a variety of colors and has been studied to meet the needs of these users. Through quantitative measurements in this work, we confirm that color differences remain depending on the difference in placement on the 3D printer bad. In addition, the temperature of the specimen was measured at the start of 3D printing, during manufacturing, and at the completion of manufacturing, and the inner and central sides remained similar, but the outer sides were 5 degrees lower. These temperature differences accumulate as layers pile up, resulting in differences in weight or color, which in turn meet consumer and producer needs in the 3D printer industry.

Additive manufacturing technology, 3D printing, has been applied to various industrial fields. This production method is a production method with less material, cost and time savings, and less restrictions in shape, and is also making a leap forward in the field of eco-friendly product production. In particular, FDM (fused depositon modeling) method of extrusion lamination manufacturing is widely applied in products and medical fields. And as an alternative to mold manufacturing, it is widely used in manufacturing plastic products and parts. Therefore, this paper quantitatively and qualitatively analyzes the mechanical properties according to the processing factors of the specimen through the processing of the ABS tensile specimen printed by the FDM type 3D printer and derives the optimum value.

본 연구는 아일랜드의 부활절봉기를 소재로 한 예이츠의 시 작품들을 신역사주의 비평을 적용하여 읽기를 목표로 한다. 연구자는 부활절 시편에 대한 기존 연구를 토대로 하여 당시 아일랜드의 정치 현실에 대한 시인의 복합적, 다층적인 입장 에 대한 분석을 모색한다. 예이츠의 부활절봉기 시편에 대한 기존의 선행연구는 대체적으로 문화 민족주의 운동, 사회적 이슈에 대한 계층 간의 갈등, 영국의 지배로부터 독립을 꾀하는 탈식민주의 등 세 가지 방향으로 전개되었다고 볼 수 있다. 이러한 세 가지 경향을 적극 수용하면서도 이들 연구들에서 당시 특정한 상황에 대한 구체적인 논의가 다소 부족한 점을 맥락 연구를 통해 보충하고자 한다. 이러한 보충을 위해 신 역사주의 이론을 적극적으로 참조하여, 당대의 문화 상황을 통해 예이츠의 문화민족주의의 방향성을 이해하고 시의 감상을 확장하고자 한다. 그리고 당대의 역사적 문화적 상황이 예이츠의 부활절 시들과 연관되고 수용되는 방식을 상세히 연구하고자 한다.

FDM 3D Printer is used in maker space for mass production by the maker. Makers desire to manufacture products in a variety of colors using ABS Filaments. The purpose of this study is to identify the relation between the color of resin and each position on the bed. So, when printed using the 3D Printer, we found out the difference in the colors that it appears depending on the position of the bed. To see the difference in color, basic, blue, yellow, white, and black were selected and the bed plate was divided into three sections. Specimens were measured to obtain delta E values between each sections by the chromatic differential system. Obtained delta values were analyzed by the NBS system. As a result, the delta E value of black was found to correspond to “Appreciable”. In most cases, delta E values between the middle and the outer or the inner and the outer was greater than values between the middle and the inner. Using Infrared Thermal Camera, We found that the color difference relates 3D printing positions and temperatures. As a result, the 3D printing bed positions should be considered when 3D printing mass production.

In this paper, the experimental study and finite elements analysis were conducted on homogeneous and dissimilar metals single lap-shear bonded joints to investigate the factor that affect the joint failure load. It was found that factors which have the significant effects on the failure load of the joint was stiffness of the adherends. And from experimental results, it can be confirmed that the failure load increases linearly with overlap length increases. And the failure load of dissimilar metal joints is approximately 1KN(10 ～17%) larger than homogeneous metal joints. In order to confirm this phenomenon, the stress distribution and strain distribution of the specimens were analyzed through the finite element analysis. The difference between homogeneous metals joints and dissimilar metals joints is that stress and strain in adhesive are concentrated at the end of the overlap zone close to aluminium which has lower rigidity than aluminium in case of dissimilar metals joints. From high rigidity of steel, the stress concentration in bonds are decreased and it cause increase of the failure strength at dissimilar metal joints.

박두진은 기독교 세계관의 관점에서 인간의 원죄의식과 타락한 본성, 이를 대속하는 예수의 죽음과 부활을 시로써 노래하였다. 그에게 예수는 하나님의 공의와 사랑을 실현한 인물이자 죽음을 이기고 인류를 구원한 하나님의 아들이었다. 특별히 사도행전 연작에서는 그리스도의 군사된 소명의식으로 시대와 민족을 향한 사도적 의지를 강하게 표출하였고, 이를 실현하기 위해 주어지는 고독과 고통을 기꺼이 감내하려는 정신주의자의 면모를 보여주었다. 김춘수는 역사가 주는 폭력을 체험한 후 역사의 실체에 대한 탐구의 결과로서 예수를 소재화하였다. 그에게 예수는 가장 무력한 자의 본보기로서 역사의 희생양이었다. 실체를 드러내지 않는 역사라는 괴물 앞에 예수는 사랑의 화신으로 삶을 마감한 인물이었다. 또한 예수는 부활이라는 알레고리를 통해 인류에게 하나의 심리적 진실로 자리한 신화적 인물이기도 했다. 박두진이 자신의 실존의 의미를 그리스도를 향한 열망으로 시화하였다면 김춘수 시인은 역사의 이율배반성에 대한 인간 존재의 슬픔과 그의 고통 콤플렉스를 시 쓰기 작업으로써 극복하였다.