• Convergence Security Journal
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• v.21 no.1
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• pp.177-189
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• 2021

Defense R&D is a key process for securing weapons systems determined by mid- and long-term needs to cope with changing future battlefield environments. In particular, the test and evaluation provides information necessary to determine whether or not to switch to mass production as the last gateway to research and development of weapons systems and plays an important role in ensuring performance linked to the life cycle of weapons systems. Meanwhile, if you look at the recent changes in the operational environment of the Korean Peninsula and the defense acquisition environment, you can see three main characteristics. First of all, continuous safety accidents occurred during the operation of the weapon system, which increased social interest in the safety of combatants, and the efficient execution of the limited defense budget is required as acquisition costs increase. In addition, strategic approaches are needed to respond to future battlefield environments such as robots, autonomous weapons systems (RAS), and cyber security test and evaluation. Therefore, in this study, we would like to present strategies for improving the testing and evaluation of weapons systems by considering the characteristics of the security environment that has changed recently. To this end, the improvement strategy was derived by analyzing the complementary elements of the current weapon system operational test and evaluation system in a multi-dimensional model and prioritized through the hierarchical analysis method (AHP).

• Journal of Adhesion and Interface
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• v.22 no.2
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• pp.63-68
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• 2021

Unsaturated Polyester Resin (UPR) is in general used as a resin to prepare for composite materials with reinforcing materials such as glass fibers. UPR, a thermosetting resin, is used in industry to prepare for sheet molding compound (SMC) molding prepreg that has excellent productivity and is advantageous for mass production among various molding methods of composite materials. The fiber-reinforced composite material using UPR as a matrix material is light and has the advantage of excellent physical properties, but it is weak against impact and is fragile. Four types of polyurethane were synthesized and added to UPR resin to overcome the shortcomings.

• Journal of Korea Foundry Society
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• v.41 no.3
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• pp.252-259
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• 2021

The magnesium is one of the important alloying elements in the conventional aluminum alloys. The addition of magnesium to aluminum is well known to increase the mechanical strength of the aluminum without the trade-off of the decreased elongation. However, the content of magnesium in aluminum alloys has been limited to be lower than about 5wt.% because of the high oxidation tendency of magnesium element during the manufacturing processes such as casting, hot-forming and post heat-treatments, which can deteriorate the quality and properties of the final products. In this study, new 'ECO-Almag6~9' (containing 6~9wt%Mg) alloys were investigated to be made of the ECO-Mg master alloy, which has been invented to reduce the oxidation tendency of itself. It was successfully demonstrated that ECO-Almag6~9 alloys can be fabricated through the mass-production facilities of DC casting and extrusion routes without the problems of magnesium oxidation. In addition, it was confirmed that the strength and ductility were simultaneously improved due to the addition of high magnesium contents.

• Korean Journal of Plant Resources
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• v.32 no.4
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• pp.290-295
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• 2019

This study was carried out to select the optimal condition for prothallus propagation and sporophyte formation of Leptogramma pozoi (Lag.) Ching subsp. mollissima (Fisch. ex Kunze) Nakaike and to provide basic data for mass production system. In the propagation, 300 mg of prothallus were inoculated in different kinds of medium [1/4, 1/2, Murashige and Skoog (MS), Knop], sucrose (0, 1, 2, 3, 4%), and cultured for 8 weeks. Sporophyte formation studies were carried out by inoculating blended prothallus into artificial soils. The soils were mixed with horticultural substrate, peatmoss, perlite, and decomposed granite at different ratios or only with the horticultural substrate. Then the prothallus was cultivated for 12 weeks to figure out the formation and growth of the sporophytes. The growth and development of prothalli were excellent on MS medium. According to medium components, prothallus growth was favorable in all treatments except 0% sucrose treatment and the highest in 2% sucrose. In the experiment of soil mixtures, sporophyte formation was the highest in the horticultural substrate:perlite 2:1 (v:v) and horticultural substrate:decomposed granite 2:1 (v:v) treatment, and the overall growth was good in the horticultural substrate:decomposed granite 2:1 (v:v) mixed soil.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.25-32
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• 2019

The purpose of this study is to investigate how to make a proper investment in ICO in the market. Previously, companies used to borrow money from banks or to obtain investments from venture capital (VC) and angel investors, but now ICOs are used as a new type of funding and financing model. The ICO sells the tokens or coins created on the blockchain openly online to raise the necessary funds, and provides the market value by paying the tokens or coins as much as the investment amount. According to this study, the limitations of the ICO market are (1) difficulties in evaluating the company, (2) uncertainties in investments, (3) lack of legal safeguards, and (4) measures to secure corporate stability after recruitment. At present, there is no way to cope with this systematically since the ICO is not protected in the legal framework. Nevertheless, we investigated the ways to make proper investment in the existing ICO market. In investing in ICO, investors should (1) consider investment methods and profitability, and (2) verify and judge investment fraud through various channels (ex. Homepage, composition team profile, etc.) and make investments based on this. This study will contribute to the formation of a healthy ICO market by understanding the newly emerged ICO market and studying the considerations when investing in it, thereby contributing to the right investor training and reducing the mass production of consumer damages caused by fraud. The limitation of this study is that the domestic ICO has not yet been examined in the legal framework, so further research is needed when policy changes occur in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.372-378
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• 2021

A body armor vest is a form of munition related directly to the safety and life of combatants. Therefore, it must meet the requirements for ballistic resistance. The ROK demands the performance of body armor vest meet the Level IIIA specified by the NIJ STD-0101.06 published by the US National Institute of Justice. This study performed acceptance tests on body armor vests. The factors for evaluating the ballistic resistance evaluated were not only whether it penetrates when shooting but also whether the BFS (Backface Signature) depth does not exceed 44 mm when it does not penetrate. The factors were assessed to determine if they were consistent or not. The BFS depth is affected by various test factors, such as the physical properties of the backing material and the changes in the amount of impact with the bullet velocity. In this study, an analysis of the bulletproof performance was performed by extracting the data with the same conditions using ANOVA to remove the influence of these external factors. The analysis revealed a correlation between the BFS depth, bullet velocity, vest conditions, and protection area. The mass production process was analyzed by estimating the Interval of BFS on each lot. Through this, a new methodology for ballistic resistance evaluation and paradigm for future quality assurance is suggested.

• Composites Research
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• v.33 no.6
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• pp.360-364
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• 2020

Although research and development of existing steel-made Cowl Cross Member(CCM) was carried out with magnesium and plastic to make vehicles lighter, it is difficult to apply them to performance problems in the vehicle's mounting condition. Recently, the company is conducting research on the injection CCM of the composite insert as a lightweight component that is most suitable for mass-production of automotive parts. This is a manufacturing process that inserts composite injection bracket parts into aluminum bar, and the adhesion of the two parts is one of the important factors considering the vehicle's mounting conditions. In this study, the joint strength of Aluminum bar is one of the important factors as a study for the injection of aluminum bar into PA6-GF60 composite material. For the analysis of these research, the method of spraying adhesive to the aluminum bar and the case of knurling treatment have been analyzed and the bonding strength of the direction of rotation and lateral direction has been analyzed for each part between the aluminum bar of the cowl cross member and the shape of the injection component of composite materials.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.97-105
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• 2020

Recently, as the data speed and operating frequencies of Ethernet keeps increasing, electro magnetic interference (EMI) also becomes increasing. The generation of such EMI will cause malfunction of near electronic devices. In this study, EMI filters were applied to reduce the EMI generated by DC-DC SMPS (switching mode power supply), which is the main cause of EMI generation of Ethernet switch. As the EMI filter, MLCCs with excellent withstanding voltage characteristics were used, which had advantages in miniaturization and mass production. Two types of EMI MLCC filters were used, which are X-capacitor and X, Y-capacitor. X-capacitor was composed of 2 MLCCs with 10 nF and 100 nF capacity and 1 Mylar capacitor. Y-capacitor was consisted of 6 MLCCs with a capacity of 27 nF. When only X-capacitor was applied as EMI filter, the conductive EMI field strength exceeded the allowable limit in frequency range of 150 kHz ~ 30 MHz. The radiative EMI also showed high EMI strength and very small allowable margin at the specific frequencies. When the X and Y-capacitors were applied, the conductive EMI was greatly reduced, and the radiation EMI was also found to have sufficient margin. In addition, X, Y-capacitors showed very high insulation resistance and withstanding resistance performances. In conclusion, EMI X, Y-capacitors using MLCCs reduced the EMI noise effectively and showed excellent electrical reliability.

• Resources Recycling
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• v.30 no.3
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• pp.3-17
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• 2021

Currently, there is a drain of natural resources, environmental contamination, generation of waste, and problems of the earth's climate by CO₂ emissions according to mass production and overconsumption of mankind. It is effectuated by a linear economy that involves manufacturing products, use, and waste repeatedly; there is no guarantee in the lives of humans and the future of the globe if we do not find alternative proposals. For a sustainable developing society and to overcome the present global problems, we must successively change to a circular economy from a linear economy. The circular economy has the concept of an extended value chain in recovery, reuse, remanufacturing, and recycling, instead of discarding after the use of manufactured goods. New business models of circular economy have been realized to save the earth ecology and sustainable developing society in serious recognition of the linear economy system. New business models are established by creating a vision and developing a program, and by renovating technology, law, and financial support through a worldwide government policy.

• Clean Technology
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• v.27 no.2
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• pp.132-138
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• 2021

Research is being conducted on graphene to provide graphene having both excellent physical as well as electrical properties in addition to unique physical properties. In this study, Hummer's method, which is a representative method for chemical exfoliation, was applied in order to investigate the possibility of the mass production of high-quality graphene oxide. Three types of graphite (graphite, crystalline graphite, and expanded graphite) were used in the preparation of graphene oxide with variations in the amount of potassium permanganate added, reaction temperature, and reaction time. Then a Fourier transform infrared spectroscopy (FT-IR), a Raman spectrometer, and a transmission electron microscope (TEM) were used to measure the quality of the prepared graphene oxide. Of the three types of graphite used in this experiment, crystalline graphite showed the highest quality. The prepared graphene oxide was then purified with an organic solvent, and an analysis conducted using energy dispersive X-ray spectroscopy (EDS). From the results of the residual values, we were able to confirm that both acid wastewater and wastewater were best purified using cyclohexane. The method for manufacturing graphene oxide as well as the method of purification using organic solvents that are presented in this study are expected to have less of an environmental impact, making them environmentally friendly. This makes them suitable for use in various industrial fields such as the film industry and for heat dissipation and as coating agents.