• Applied Chemistry for Engineering
• /
• v.22 no.6
• /
• pp.648-652
• /
• 2011

Passive autocatalytic recombiner (PAR) is considered as an explosive gas control system in operating NPP plants. This work investigates and evaluates hydrogen recombination performance over manufactured $Pt/TiO_2$ catalysts. When the space velocity increases, the hydrogen conversion decreased, while hydrogen depletion rate (g/sec) increases highly in $35000{\sim}100000hr^{-1}$ Gas Hourly Space Velocity (GHSV). Hydrogen conversion and depletion rate with Pt loading is investigated. As a result, there were no differences in the hydrogen conversion, but exothermic heating rate (K/sec) is increases as Pt loading increases. The catalyst showes a high hydrogen conversion efficiency of 80% under atmospheric conditions.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.10
• /
• pp.1298-1304
• /
• 2019

Since the 9·11 terror attack in 2001, the Maritime Logistics Security System has been strengthened and required X-ray image for every imported cargos from manufacturing countries to United States. For scanning cargos, the container inspection systems use high energy X-rays for examination of contents of a container to check the nuclear, explosive, dangerous and illegal materials. Nowadays, the X-ray cargo scanners are established and used by global technologies for inspection of suspected cargos in the customs agency but these technologies have not been localized and developed sufficiently. In this paper, we propose the X-ray array detector system which is a core component of the container scanning system. For implementation of X-ray array detector, the analog and digital signal processing units are fabricated with integrated hardware, FPGA logics and GUI software for real-time X-ray images. The implemented system is superior in terms of resolution and power consumption compared to the existing products currently used in ports.

• Transactions of the Korean hydrogen and new energy society
• /
• v.34 no.5
• /
• pp.535-548
• /
• 2023

The intermittent nature of renewable energy is a challenge to overcome for safety and stable performance in water electrolysis systems linked to renewable energy. Oxygen removal using the catalyst is suitable for maintaining the oxygen concentration in hydrogen below the explosive level (4%) even in intermittent power supply. Metals such as Pd, Pt, and Ni are expected to be effective materials due to their hydrogen affinity. The oxygen removal performance was compared under high hydrogen concentration conditions by loading on γ-Al₂O₃ with high reactivity and large surface area. The characteristics of the catalyst before and after the reaction were analyzed through X-ray diffraction, transmission electron microscope, H₂-temperature programmed reduction, X-ray photoelectron spectroscope, etc. The Pd catalyst that showed the best performance was able to lower 2% oxygen to less than 5 ppm. Changes in catalyst characteristics after the reaction indicate that oxygen vacancies are related to oxygen removal performance and catalyst deactivation.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.12
• /
• pp.55-63
• /
• 2015

Recently, terroristic threats using a radio controlled improvised explosive device (RCIED) that is remotely controlled and exploded have been increased around the world. In order to prevent the explosion of an RCIED, jamming techniques that interrupt an RCIED receiver can be used, so that the receiver can not demodulate the trigger code. Conventional jamming technique is a type of active barrage jamming that always emits the noise jamming signal for all the frequency band. However, it needs large power consumption and thus is limited in operation time for a vehicle. In order to overcome the shortage of the active barrage jamming, reactive jamming technique has drawn attention. In reactive jamming, all the frequency band is firstly scanned, and then if any trigger signal exists, one emits the jamming signal to the corresponding frequency band. Therefore, the reactive jamming is superior to the active barrage jamming in terms of power efficiency. However, a reactive jammer emits a jamming signal only after the trigger signal is intercepted, which means that the jamming signal may be late for interrupting an RCIED receiver. In this sense, it is needed to evaluate a delay in an RCIED receiver. To achieve this, we analyze the reaction time and present the simulation result for jamming performance of reactive jamming against an RCIED using mobile devices.

• Strategy21
• /
• s.31
• /
• pp.190-219
• /
• 2013

Since Korea and Japan established diplomatic relationship, Relationship between Korea and Japan has not been easygoing. There are two most explosive, and noticeable ones among topics which have affected the relationship ; Dokdo and Historical Distortion. Without these issues, relationship between two countries will take a turn for the better. However, unfortunately, it seems that it is almost never going to happen. There is the Japanese conservative right-wing who has an influence on those two issues. The right-wing takes regard getting negative view or finding out dark past as an action from Self-torture view of history, and tries to dilute the Japanese sense of guilt on past invasions to neighbor countries. Moreover, to become a "normal country", they are trying to revise Constitution of the Japan so that Japan can possess the military and re-arm, dispatch troops abroad, and get the right to break the war. In other words, they expect Japan to become a powerful nation with great influence on Asia and world, as the period in which Japan conquered Korean peninsula, China, and South-Eastern nations. Japan still harbours secret romanticism for bygone days of imperialist glory. That is why neighbors want to never make the painful history happen again. In order to deal with this effort, most of all, it is required to assert better argument with a careful, thorough analysis on Japanese opinion about Dokdo. There might be a hidden card which can be accepted in the international society considering Japanese persistent effort to make Dokdo disputed area, and that is why we have to know that it is. In addition, it is needed to secure a high-quality professional manpower because the issues of Dokdo and Historical Distortion are primarily the matter of logic and references. The professional manpower should have open-minded to break down walls of their own majors. We have to introduce our achievements and stances to the international society vigorously. As a definite way to solve these problems, we have to develop national power. We have to possess naval forces and coast guard to protect our territory and Koreans overseas. There are not many options Korea can do to Japan, except protesting denunciation, and pressing a joint efforts. Most of the suggestions stated before are what have to be conducted domestically. It is a miserable condition, because two problems are Japanese domestic issues, but they become international issues and we have to seek a solution for ourselves.

• Explosives and Blasting
• /
• v.28 no.2
• /
• pp.1-16
• /
• 2010

This study focuses on the phenomenon that the blast damaged zone developed on rock slope surfaces can be affected by joint characteristics rather than by explosive power when the pre-splitting is applied to excavate a jointed rock slope. The characteristics of rock joints on a slope were investigated and categorized them into 4 cases. Also an image processing system has been used for comparing the distribution pattern of rock blocks. From this investigation, it was found that the rock blocks bigger than 2,000 mm occupied 42% in the case of single joint set and it showed the well efficiency of pre-splitting blast. In cases of 2~3 parallel joint sets and 2~3 intersecting joint sets are developed on rock surfaces, the rock blocks in the range of 1,000~2,000 mm occupied 43.6% and 35.8%, respectively, and it showed that the efficiency of pre-splitting was decreased. When more than 3 joint sets are randomly developed, however, the rock blocks in the range of 250~500 mm occupied 35% and there was no block bigger than 1,000 mm. This denotes that the blasting with pre-splitting was not effective. The numerical analysis using PFC2D showed that the blast damaged zone in a rock mass could be directly influenced by the pre-splitting. It is, therefore, required to investigate the discontinuity pattern on rock surfaces in advance, when the pre-splitting method is applied to excavate jointed rock slopes and to apply a flexible blating design with a consideration of the joint characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.5
• /
• pp.557-562
• /
• 2018

Unlike live ammunition which has killing power due to the use of high explosives, training ammunition has only the limited explosive effect needed for training purposes, so the risk of accidents is lowered. Because training ammunition is used in large quantities during military drills, the problem of environmental pollution occurs. As most of the waste is left out in the training field, using bio-degradable polymers such as Polylactic Acid (PLA) can provide a solution to these environmental issues. However, bio-degradable polymers such as PLA usually have poor thermal and mechanical properties compared with other general purpose polymers, so they need to be improved before they can be used for military purposes. In this study, Talc is added to the PLA used for the parts of Training Grenades to improve some of their properties and the changes of their thermal and mechanical properties were verified. In the case of the 1 wt.% ~ 5 wt.% PLA/Talc blends, the thermal properties were improved in proportion to the content of Talc, but the best mechanical properties were observed for the 1 wt.% and 3 wt.% PLA/Talc blends.

• Korean Journal of Optics and Photonics
• /
• v.28 no.4
• /
• pp.166-171
• /
• 2017

Hydrogen gas is a green energy sources because it features no emission of pollutants during combustion. But hydrogen gas is very dangerous, being flammable and very explosive. Hydrogen gas detection is very important for the safety of a nuclear power plant. Hydrogen gas is generated by oxidation of nuclear fuel cladding during a critical accident, and leads to serious secondary damage in the containment building. This paper discusses the development of a Raman lidar system for remote detection and measurement of hydrogen gas. A small, portable Raman lidar system was designed, and a measurement algorithm was developed to quantitatively measure hydrogen gas concentration. To verify the capability of measuring hydrogen gas with the developed Raman lidar system, experiments were carried out under daytime outdoor conditions by using a gas chamber that can adjust the hydrogen gas density. As results, our Raman lidar system is able to measure a minimum density of 0.67 vol. % hydrogen gas at a distance of 20 m.

• Korean Journal of Optics and Photonics
• /
• v.29 no.3
• /
• pp.119-125
• /
• 2018

Hydrogen gas is an important and promising energy resource that has no emissions of pollutants during power generation. However, hydrogen gas is very dangerous because it is colorless, odorless, highly flammable, and explosive at low concentration. Conventional techniques for hydrogen gas detection are very difficult for measuring the hydrogen gas distribution at long distances, because they sample the gas to measure its concentration. Raman lidar is one of the techniques for remotely detecting hydrogen gas and measuring the range of the hydrogen gas distribution. A Raman lidar system with an on-axis optical receiver was developed to improve the range of hydrogen gas detection at long distance. To verify the accuracy and improvement in the range of detecting the hydrogen gas, experiments measuring the hydrogen gas concentration are carried out using the developed on-axis Raman lidar system and a gas chamber, to prevent explosion of the hydrogen gas. As a result, our developed on-axis Raman lidar system can measure a minimum hydrogen gas concentration of 0.66 volume percent at a distance of 50 m.

• 한국보건간호학회:학술대회논문집
• /
• 2002.10a
• /
• pp.224-227
• /
• 2002

Alcoholism affects not only the individuals who depend on it, but also their families. Children who have an alcohol dependent parent have various problems and need help, but little attention has been given to them. Many references report only negative characteristics of these children. In order to help the children of alcohol dependent parents, health professionals need more information. A wholistic understanding and analysis of these children is needed as a basis for the development of suitable programs of help them. A phenomenological methodology was used to identify the experience of children whose fathers were addicted to alcohol. The findings portray the essence of the lived experience of children of alcohol dependent fathers. Nine adolescents participated in in-depth inverviews and observation with the researcher, done between October and December 2001. The data were recorded on audio tape and transcribed. Sampling was continued until the data were theorectically saturated. The Colaizzi's method was used for data analysis. The results of this study are as follows. Three themes and twenty six meanings were identified. The first theme is Living Alone: living abusively as partner to an alcohol dependent father, living dangerously like an explosive fury, living as an object that ha no self, living with rejection of fatherly being, living with felt responsibility but having no power to help mother who suffers patiently with pain and abuse, living along with no shoulder to lean on, and living with the prejudice of sex discrimination. The second theme is Paradoxical Coping in Life. The meanings are obsessive behavior as a way to control father's behavior, always on the defensive due to anxiety and tension, being afraid of life alone due to paranoid thoughts, contradictory expectation about father's drinking behavior due to life with chronic tension, stress becoming familiar and life being boring and tendious without stimulation, life that is fake and filled with misinterpretations about reality, affection sought from others due to loneliness, compensatory life within peer group, negative expectation about the future due to negative experiences, controling others to protect ego, denial of real emotion to protect self from hurt, life of regretting self, and strong need for approval from others. The third theme is sustaining life. The meanings are ambivalence between revenge on father and pity, struggle for desirable self against fear of gather-like image, understanding father through self reflection, hope to find fatherly being through father's recovery, being able to stand through emotional control and cognitive restructuring, nurturing the seed of hope for the future while in a situation of desperation. The contribution of this study is to give a wholistic understanding of the empirical reality of children of alcohol dependent parents and to develop substantive theory in nursing knowledge. In nursing practice, the results of this study can provide a foundation for the development of programs for children of alcohol dependent parents.