Earticle

Various optical devices are utilized to fire artillery in Korean Army. To transport and store the optical devices, some cases are made up for a set. The covers of cases are made of Glass Fiber Reinforced Plastic(GFRP) and resin. Because of materials of case, it has a disadvantage in productivity for manufacturing covers and assembling components. In this study, ABS resin is presented for alternative and verify possibility through FEM analysis. Comparing with GFRP, max stress-ratio of ABS is decreased 19.6% for bottom, 8.2% for side and 25.4% for edge. Also each strain is changed 17.3%, 180.3% and 17.7%. According to the research results, ABS resin is considered possible for alternative. And the number of components is decreased for around 73.8%.

In this study, we intend to develop a control valve with oxidation resistance for hydrogen fluoride that can be applied to the semiconductor production process. Operated Valves currently in use is a form of assembling an air cylinder to the valve body. These valves generally have a cylinder body made of aluminum (Al), so they may corrode depending on the external environment, and the solution leaks along the rod inside the cylinder, causing damage to parts due to corrosion. To solve this problem, the valve plug shape was developed by devising and applying a plug using a valve different from the existing method, and it is possible to block the inflow of hydrogen fluoride into the valve control unit, thereby preventing damage to parts as well as maintaining stable valve operation.

In this study, 3D design, vibration analysis and experiment, and feed rate performance test were performed to develop a vibratory bowl feeder for supplying ultra-thin plate parts of less than 50 microns. The natural frequency and resonant frequency of the vibratory bowl feeder were obtained through the vibration analysis and experiment, and it was confirmed that the results of the analysis and experiment agree well. Through the feed rate experiment, it was confirmed that up to 610 ultra-thin parts per minute were fed at 250Hz and a supply voltage of 220V, where the excitation frequency and the resonant frequency match. And through analysis and experimental research, it was confirmed that the development of a vibratory bowl feeder for supplying ultra-thin parts was successful.

This paper proposes a solution to the out-of band oscillation signal and in-band low transmitter power output that occurrs during the low-temperature operation test for the new mine detector GPR signal transmission and reception module. Tests were performed by applying the optimal values of capacitors and inductors through circuit analysis simulation under the limited space, as a result, it was confirmed that the gain and return loss were improved at all-band thereby preventing oscillation signal and low transmitter power output.

In order to manufacture a mask to prepare for infectious diseases such as COVID-19 and yellow dust, it is manufactured through the process of input, fusion, cutting, band attachment, defect inspection, and packaging. Domestic mask producers introduced Chinese facilities to keep up with explosive demand due to the rapid spread of COVID-19 in 2020, but serious problems arise in durability. Therefore, domestic processing and tooling companies have developed and supplied molds, but since supply is not smooth compared to demand, research on the development of mask molds with durability reliability is urgently needed to supply masks stably. This technology development aims to supply a mask with excellent quality to a market by applying dots capable of welding and re-painting to a mold for cutting applied to a mask manufacturing process and developing dots optimized for paper angles.

In this study, using the developed pilot device, an experiment was conducted with groundwater according to the calcium carbonate concentration and silica concentration for a certain period of time to determine the degree of RO membrane contamination according to water quality. In addition, using wastewater with severe fouling of raw water, the treatment efficiency is compared through an experiment with a pilot device, the operation progress is evaluated for the scale effect, and the stability and convenience of the developed product are considered.