Artificial graphites have been used in various applications, for example, as anode materials for Li-ion batteries, C/C composites, and electrodes for aluminum smelting, due to their unique mechanical strength and high thermal and electrical conductivity. Artificial graphites can be manufactured by a series of kneading, molding, carbonization and graphitization processes with an additional impregnation process. In this study, the influence of the process variables in the kneading and carbonization/graphitization process on the properties of the resulting carbon block was systemically investigated. During the kneading process, the optimum kneading temperature was 90 °C higher than the softening point of the binder pitch; thus, the binder pitch reached its maximum fluidity. On the other hand, during the carbonization and graphitization process, the structural properties of carbon blocks prepared at different heat treatment temperatures were examined and their structural change and evolution were closely described according to the temperature and divided into low-temperature carbonization and high-temperature carbonization/graphitization. Based on this study, we expect to provide a better understanding of setting the parameters for thermally conductive carbon block manufacturing.

This study attempted to interpret the meaning of the U.S.-China hegemony competition based on liberal theory, and predicted future U.S.-China relations by analyzing the hegemony confrontation between the U.S. and China. During the U.S.-China hegemony competition, countries around China, which are directly threatened by China, were divided into continental and maritime national groups, and the characteristics, concerns, and responses of those countries were considered. It proposed a new maritime-new continent global bridge economic block system, suggested strengthening economic cooperation, technical cooperation, cultural cooperation and liberal international order as its effectiveness, and suggested the need of a new international order during the Fourth Industrial Revolution.

A laser scabbling experiment was performed using a high-power fiber laser to investigate the removal rate of the concrete block and the scabbled depth. Concrete specimens with a 28-day compressive strength of 30 MPa were used in this study. Initially, we conducted the scabbling experiment under a stationary laser beam condition to determine the optimum scan speed. The laser interaction time with the concrete surface varied between 3 s and 40 s. The degree of spalling and vitrification on the surface was primarily dependent on the laser interaction time and beam power. Furthermore, thermal images were captured to investigate the spatial and temporal distribution of temperature during the scabbling process. Based on the experimental results, the scan speed at which the optical head moved over the concrete was set to be 300 mm∙min−1 or 600 mm∙min−1 for the 4.8-kW or 6.8-kW laser beam, respectively. The spalling rates and average depth on the concrete blocks were measured to be 87 cm3∙min−1 or 227 cm3∙min−1 and 6.9 mm or 9.8 mm with the 4.8-kW or 6.8-kW laser beams, respectively.

LNG makes cryogenic conditions, so metals without low-temperature brittleness must be used. The International Maritime Organization (IMO) defines 9% Nickel steel, STS304L, 36% Nickel steel and Al5083 as metals that can be used in cryogenic conditions through the IGC Code. In this study, Al5083-O was studied to minimize welding distortion, and verified through finite element analysis and experiments. The block dumping method, which is advantageous in terms of analysis time and cost, was used, not the continuous heat source method. The constraint models with the thickness direction and the tensile force model were compared with the reference model, it was confirmed that the tensile force model had no significant effect. After verifying through the experiment, it was confirmed that the trend of the finite element analysis model was consistent with the experiment. Through this study, a welding distortion minimization model could be found with the block dumping method. It is judged that simulation of many models through short time analysis will be of great help in the field.

The aim of this study is to define the new expressive techniques for multicolored clamp resist (hyuphill) dyeing, based on empirical verification on relics that are estimated to be dyed by the exchange of more than two wood blocks: a previously undiscovered technique. Clamp resist dyeing (assumed to be made by exchanging wood blocks) have uneven resist printing lines or cloudy gradation. These are reproduced as follows: first, they have uneven contour lines, particularly with the color blue. It is possible to exchange wood blocks separately on patterns with uneven resist printing lines, and it has been verified that the exchange of wood blocks makes these irregular resist printing lines. It has also been verified that exchanging the wood blocks according to the gradation (to emphasize the cubic effect on the patterns) yields clamp resist dyeing with no resist printing lines but with cloudy gradations that have accented borders. This study provides basic information that enables methods of multicolored clamp resist dyeing through wood block exchange to be deduced (something that has not been attempted for a long time). Thus, the revival of the modern Korean dyeing culture based on the conservation and perseverance of the traditional dyeing techniques can be achieved.

This study was conducted to compare the mechanical properties of NAB (Ni-Al-Bronze) material manufactured using WAAM (wire arc additive manufacturing) technology and cast NAB that has been used. Two types of mechanical property test pieces were collected from the deposited bulk NAB material according to the direction of deposition, and compared with each other. As a result of mechanical property evaluation, the deposited NAB exhibited anisotropy according to the direction of deposition, and showed high tensile strength, hardness, and shock absorption in the longitudinal direction of the welding line.

As the importance of three-dimensiona (3D) nano patterns and structures has recently emerged, interest in the study of 3D structures of block copolymers has increased. However, most existing studies on block copolymer 3D patterns on substrates are limited to simple 3D structures such as a multi-layered forms. In this study, we propose an experimental method for realizing free-standing 3D block copolymer patterns on substrates using an e-beam lithographic template and film transfer method. The block copolymer 3D structure formed in wide hole templates are similar to simple multi-layered structures; however, as the width of the hole template become narrower, more complex block copolymer 3D structures are formed in which the upper and lower layer structures are interconnected. Furthermore, we introduce a method to fabricate novel block copolymer structures in which the 2D planar structures are connected to 3D complex structures. Proposed 3D block copolymer fabrication method provides a framework for generation of unconventional 3D structures of block copolymer, which can be useful for next generation 3D devices.

Although mud shrimp (Upogebia Major) provides benefits on the tidal flat ecosystem, it is causing the mass mortality of Manila clam (Tapes philippinarum) and large economic loss to the aquaculture farmer due to spreading in the entire coastal clam farm area of the West Sea of Korea. In this study, a mud shrimp blocking box for cultivating clam was tested to prevent the mud shrimp from invading the habitat of the clam. To determine the effect of the blocking box, the growth characteristics of the clams under various culture conditions were investigated. The shell length, total weight, condition index, the presence of mud shrimp in the box, and the soil decay in the box were examined according to whether the clams were raised in the box or in natural state, whether the box is covered with a net or not and the gap size of the box. As a result, no significant differences in shell length, total weight, and condition index were found between the clam grown in the box and the natural state (P>0.05) without any evidence of invading of mud shrimp to the box. In addition, the soil inside the box was in good condition, not decayed. Therefore, using the mud shrimp blocking box, mud shrimp can be prevented from propagating to the habitat of the clam, thereby contributing to the normal production of the clam and thus to restoring the clam farming.

PURPOSES: The objective of this study is to evaluate and compare the stiffness characteristics and seasonal variation in surface deflections of block and asphalt pavements using the light weight deflectometer (LWD) and falling weight deflectometer (FWD). METHODS: LWD and FWD testing was conducted on block and asphalt pavement sections in a low-impact development facility, to evaluate the structural capacity and seasonal variation in asphalt pavements. To analyze the seasonal variation in stiffness characteristics, this testing was performed in October 2016, January 2017, and March 2017 in the same drop locations. RESULTS : It was found from that the average center deflections in the asphalt and block pavements were 218 ㎛ and 2974 ㎛, respectively. The center deflections measured using FWD testing in block pavement are 15 times those measured in asphalt pavement. It was also observed that LWD deflections in block pavements were decreased by approximately 65-90% as the air temperature dropped from 20 to 4℃. The degree of reduction in block pavement was significantly higher when compared with asphalt pavement, which showed a 25- 50% reduction in deflection. CONCLUSIONS: When using block pavements for roadways, the structural capacity of the pavement system should be considered during the design and construction stages. In block pavements, the use of low-quality material and insufficient compaction in the base and subgrade layers can induce a reduction in structural capacity, which would lead to the need for frequent repair work. A reinforcement underneath the block layer would be an appropriate measure for improving the structural support and extending the service life.

PURPOSES : The purpose of this study is to develop a solar powered block pavement system satisfying the road design criteria in Korea. The concrete block pavement system was chosen as the most suitable for development at the current level of technology. METHODS : A new solar block pavement system was conducted by seperating the solar module from the concrete block. The solar panel module is responsible for the solar powered system and the solar concrete block is responsible for the vehicle load support. Quality criteria for block pavements in Korea were collected to select the appropriate quality criteria for a solar block pavement system. The laboratory tests conducted were slip resistance test, compressive strength test and absorption rate test of the concrete blocks, flexural strength test of the acrylic protection panel, and UTM load test of the solar panel module. Solar power measurement was also conducted at the field test section for field performance evaluation. RESULTS : The acrylic protection panels were selected as 15mm thick panels with diagonal patterns of 45°, considering the power generation efficiency, appropriate thickness of the solar power modules, slip resistance and flexural strength. The results of the laboratory tests for evaluating the structural performance of concrete blocks demonstrated that the compressive strength and absorption rate were 22.7 MPa and 3.4% on average, respectively. From these results, it can be observed that the concrete blocks of the solar block pavement system satisfy the block pavement criteria in Korea. As a result of the UTM load test of the solar panel module, the maximum compressive load was found to be 26 tonf on average, and it was confirmed that damage does not occur under a passenger car load. CONCLUSIONS : A new solar block pavement system was developed by seperating the solar module and concrete block. As a results of the laboratory and field tests, both the solar module and concrete block satisfied the quality criteria for block pavement in Korea.