• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.1
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• pp.59-66
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• 1998

The combustion instability analysis of solid propellants is generally done by the simplified governing equations for chemically inert condensed phase region with QSHOD assumption. Since the gas phase and surface reaction layer can be more rapidly relaxed to the external perturbations than the condensed phase, these regions are treated as quasi-steady manner in the analysis. In this paper, the classical ZN(Zeldovic-Novozhilov)approach was re-examined with the presence of radiation augmented burning enhancement in the combustion. Also, the surface reaction was assumed to partially absorb the incident radiant heat fluxes and pass the remaining to the chemically inert condensed phase. As a result of the analysis, the burning rate response function was obtained which consists of a pressure response function and a radiation response function. The response function was shown to be able to predict the results of T-burner tests.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.769-775
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• 2021

The objective of this research was to analyze the factors influencing the farm-gate shrimp prices in Thailand using monthly time series from January 2001 to December 2019. The econometric methodology was employed to satisfy the purpose, consisting of the cointegration test for revealing the long-run relationship and equilibrium elasticity between the variables as well as the error correction model for detecting speed adjustment to shock responses. The empirical results revealed that (1) the export shrimp prices, shrimp production in the country, and shrimp export volume indicated a long-run relationship running to the farm-gate shrimp prices in Thailand with the size of equilibrium elasticity equal to 1.083%, -0.256%, and 0.123, respectively, and (2) the farm-gate shrimp prices in Thailand would adjust to the equilibrium line with a speed equal to 20.147% if there was any kind of incident or shock which caused the relationship to deviate from the equilibrium point. There was no relationship in terms of global shrimp prices and the exchange rate for farm-gate shrimp prices in Thailand. The recommendations should emphasize the varieties of shrimp products for export to other countries beyond the main trading markets nowadays to reduce risks and fluctuations in the export prices of shrimp products.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.2
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• pp.16-25
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• 2019

While various efforts are being made to ensure aviation safety, air accident rate induced by pilot human factors is still high worldwide. In particular, among pilot human factors, it would be the most important issue for pilots to anticipate and recognize flight environmental factors beyond their control and to make a positive decision making(ADM). In the Republic of Korea Air Force(ROKAF), there were many dizzying experiences induced by bird strike incidents and developed into dangerous moments such as damage to the aircraft and pilots' increased mental stress. It is a matter of serious concern in terms of safety management and human factors to dismiss bird strike incidents as inevitable misfortune due to environmental factors. In 2018, the ROKAF Aviation Safety Agency(ASA) conducted an experimental study to enhance pilots' ADM competence that can anticipate and avoid a bird strike. As the way of the study, 'Bird Strike Preventing Information' had been written and distributed every week by the ASA to flight units in the ROKAF during the period of the study. Through enhanced pilots' perceptual ADM competence, there was a noticeable number of reduction in bird strike incident compared to previous years of the experimental study.

• Journal of Preventive Medicine and Public Health
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• v.52 no.1
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• pp.66-70
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• 2019

Objectives: In the Republic of Korea (ROK), the notified incidence of tuberculosis in foreign-born individuals (NITFBI) has increased recently, as has the rate of multidrug-resistant (MDR) and rifampicin-resistant (RR) tuberculosis in foreigners staying in the ROK. As Jeju Province in ROK has a no-visa entry policy, control programs for NITFBI should be consolidated. The aim was to evaluate the status of NITFBI, with a focus on the distribution of MDR/RR tuberculosis by nationality. Methods: Data on tuberculosis incidence in individuals born in Jeju Province and in foreign-born individuals were extracted from the Korean Statistical Information Service of Statistics Korea, and the Infectious Disease Surveillance Web Statistics of the Korea Centers for Disease Control and Prevention, respectively. Results: Among all notified incident cases of tuberculosis, the proportion of NITFBI increased from 1.46% in 2011 to 6.84% in 2017. China- and Vietnam-born individuals accounted for the greatest proportion of the 95 cases of NITFBI. Seven cases of MDR/RR tuberculosis were found, all involving patients born in China. Conclusions: In Jeju Province, ROK, NITFBI might become more common in the near future. Countermeasures for controlling active tuberculosis in immigrants born in high-risk nations for tuberculosis should be prepared in Jeju Province, since it is a popular tourist destination.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.2
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• pp.133-140
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• 2019

In this paper, the penetration process of Shaped charge jet(SCJ) was simulated through finite element analysis to obtain physical quantities such as jet incidence velocity, penetration rate, and penetration increment. As a result of applying these physical quantities to the hydrodynamic theory, it was confirmed that the penetration efficiency of the jet with a high incident velocity is higher than that of the following slow jet. This efficiency decreased sharply when the jet was slower than the hydrodynamic limit(HL). On the other hand, the comparison of penetration increment and jet consumption over time showed that the length extension effect should be considered for SCJ's theoretical penetration analysis.

• Journal of Surface Science and Engineering
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• v.56 no.4
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• pp.265-272
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• 2023

Photoelectrochemical (PEC) water splitting is one of the promising methods for hydrogen production by solar energy. Iron oxide has been effectively investigated as a photoelectrode material for PEC water splitting due to its intrinsic property such as short minority carrier diffusion length. However, iron oxide has a low PEC efficiency owing to a high recombination rate between photoexcited electrons and holes. In this study, we synthesized nanoporous structured iron oxide by anodization to overcome the drawbacks and to increase surface area. The anodized iron oxide was annealed in Ar atmosphere with different purging times. In conclusion, the highest current density of 0.032 mA/cm² at 1.23 V vs. RHE was obtained with 60 s of pursing for iron oxide(Fe-60), which was 3 times higher in photocurrent density compared to iron oxide annealed with 600 s of pursing(Fe-600). The resistances and donor densities were also evaluated for all the anodized iron oxide by electrochemical impedance spectra and Mott-Schottky plot analysis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.632-634
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• 2021

In proportion to the development of the Internet and the increase in users, the rate of cyber-incident using it is increasing. As a countermeasure, there is a network separation method that separates the system accessible to users and the system containing key information from each other. However, in the case of tasks that require the use of the Internet network, it is exposed to cyber attacks, and there are many loopholes in the method of data transmission between networks and the management and operation of the system, resulting in infection of the closed network. In this paper, we aim to enhance the safety of the networking system by investigating the types and cases of infringement accidents in these network separation environments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.2
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• pp.202-207
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• 2024

This study examines a manufacturing process for the photoelectrode material of dye-sensitized solar cell (DSSC) intending to increase efficiency through the surface plasmon resonance phenomenon of nanoparticles with a composite structure made of Ag and TiO₂. This invention involves the use of Ag and TiO₂ nanoparticles in the solar cell. These nanoparticles cause surface plasmon resonance, which amplifies and scatters incident solar energy, enhancing the dye's rate of light absorption. It also makes it possible to absorb energy in wavelength ranges that were previously difficult to do, which increases efficiency. Centrifugal separation and heat synthesis are used to create the composite metal structures, and certain combinations are used to decide the particle morphologies. To increase the efficiency of organic solar cells and DSSC, the Ag/TiO₂ composite structure is therefore quite likely to be used.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2333-2336
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• 2013

Background: The aim of this paper was to present the incidence rates of leukemia and multiple myeloma (MM) in Golestan province located in northeastern Iran during 2004-2009. Materials and Methods: This was a descriptive cross-sectional study. Data on newly diagnosed (incident) leukemia and MM cases were obtained from collected from Golestan population-based cancer registry. Data was entered into CanReg-4 software. Age standardized incidence rates (ASR) (per 100000 person-years) for leukemia and MM were calculated. Data on Golestan population was obtained from the data of Iranian national census in 2006. Results: Totally, 11036 new cancer cases were registered in GPRC from 2004-2009. Leukemia and MM accounted for 693 and 124 of cases, respectively. The mean age in patients with leukemia and MM was 43.8 and 62.4 years, respectively. The ASRs for leukemia among men and women were 10.4 and 7.8, respectively (p<0.001). The ASRs for MM were 2.1 and 2 in men and women, respectively (p=0.93). The rate of leukemia was significantly higher in rural areas (p=0.02) whereas the incidence of MM was higher in urban areas (p<0.001). Conclusions: Our results showed a high incidence rate of leukemia in Golestan province of Iran. The incidence of leukemia was significantly higher in males and residents of rural areas. High exposure to pesticides and other agricultural related products may be a possible explanation for epidemiological pattern of leukemia in this area. Determining and controlling important risk factors, especially environmental factors, of leukemia may lead to decrease in its burden in Golestan province of Iran.

• Journal of Oriental Neuropsychiatry
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• v.10 no.1
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• pp.53-78
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• 1999

As the average life span have been lengthened and the rate of senile population have been raised, chronic degenerative diseases incident to aging has been increased rapidly and become a social problem. With this social background, recently, the facts that oxygen radicals(OR) have toxic effects on Central Nervous System and Peripheral Nervous System and cause neuropathy such as Parkinson's Disease, Alzheimer Disease have been turned out, and accordingly lots of studies on the mechanism of the toxic effects of OR on nerves, the diseases caused by OR and the approaches to curing the diseases have been made. The purpose of this study is to examine the toxic effects caused by Glucose Oxidase(GO) and the effects of herbal extracts such as Chilbokyeum(CBY), Chilbokyeumga Acori Rhizoma(CAR), Acori Rhizoma(AR) on the treatment of the toxic effects. For this purpose, experiments with the cultured cell from the cerebrums of new born mice were done. The results of these experiments were as follows. 1. GO, a oxygen radical, decreased the survival rate of the cultured cells on NR assay, MTT assay and amount of neurofilaments and increased the amount of total protein, lipid peroxidation and the amount of LDH. 2. CBY have efficacy of increasing the amount of neurofilaments and total protein and decreasing lipid peroxidation and the amount of LDH. 3. CAR have efficacy of increasing the amount of neurofilaments and total protein and decreasing lipid peroxidation and the amount of LDH. 4. AR have efficacy of increasing the amount of neurofilaments and total protein. From the above results, It is concluded that Chilbokyeumgamibang has marked efficacy as a treatment for the damages caused in the GO-mediated oxidative process. And Chilbokyeumgamibang is thought to have certain pharmacological effects on controlling over aging and treating Dementia. Further clinical study of this pharmacological effects of Chilbokyeumgamibang should be complemented.