• Journal of Korean Society of Forest Science
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• v.85 no.1
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• pp.24-33
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• 1996

The theory of reasoned action was examined as a theoretical model which explains the relationships among belief, attitude, and intention regarding the policy of limiting the total number of visitors per day in the national parks during the high-demand season. Also, effects of persuasive messages developed to change users' attitude toward the policy positively were examined. Among the visitors in Kyeryongsan National Park, 563 visitors participated in on-site and mail survey. The number of visitors who had positive and negative attitudes toward the policy was in the ratio of 43 to 49. A significantly positive relationship was found between the sum of belief and outcome evaluation crossproducts and attitude(r=0.42). Intention could be explained with attitude in an acceptable power ($R^2=0.32$). The visitors who had negative attitude and intention regarding the policy before the treatment were changed positively by the two types of persuasive messages. Among the visitors receiving the persuasive messages, 74% answered that carrying out the policy is good and 66% intended to agree to carrying out the policy. It was indicated that the persuasive messages were an effective communication method between park managers and users.

• Composites Research
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• v.29 no.1
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• pp.40-44
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• 2016

Nuclear fuel cladding used in a nuclear power plant must possess superior oxidation resistance in the coolant atmosphere of high temperature/high pressure. However, as was the case for the critical LOCA (loss-of-coolant accident) accident that took place in the Fukushima disaster, there is a risk of hydrogen explosion when the nuclear fuel cladding and steam reacts dramatically to cause a rapid high-temperature oxidation accompanied by generation of a huge amount of hydrogen. Hence, an active search is ongoing for an alternative material to be used for manufacturing of nuclear fuel cladding. Studies are currently aimed at improving the safety of this cladding. In particular, ceramic-based nuclear fuel cladding, such as SiC, is receiving much attention due to the excellent radiation resistance, high strength, chemical durability against oxidation and corrosion, and excellent thermal conduction of ceramics. In the present study, cladding with $SiC_f/SiC$ protective films was fabricated using a process that forms a matrix phase by polymer impregnation of polycarbosilane (PCS) after filament-winding the SiC fiber onto an existing Zry-4 cladding tube. It is analyzed the oxidation and microstructure of the metal cladding with $SiC_f/SiC$ composite protective films using a drop tube furnace for thermal shock test.

• Food Science and Preservation
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• v.14 no.3
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• pp.239-246
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• 2007

The effects of gamma irradiation on the physiochemical and physical characteristics of apples were investigated during post-irradiation storage at $4^{\circ}C\;and\;25^{\circ}C$. The contents of total and reducing sugars were analyzed and the results indicated that apples receiving 1 kGy of gamma irradiation did not show significant differences in sugar contents compared to non-irradiated controls. Important physiological characteristics were evaluated by measurement of total phenolic content and total flavonoid content, reducing power, and radical scavenging ability, and the results indicated that gamma irradiation at a dose of 1 kGy did not affect physiological activities. Changes in physical parameters such as weight loss, strength, cohesiveness and hardness, during post-irradiation storage, were temperature-dependent, whether the apples were irradiated or not The color and sensory acceptance of the apples were not affected by irradiation during cold storage. However, minor deterioration in color quality and sensory acceptance of irradiated apples was noted under ambient temperature storage. We conclude that gamma irradiation(1 kGy) does not affect apple nutritional content stability, functional properties, or physical characteristics, especially upon cold storage after radiation treatment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2511-2517
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• 2009

Recently, a FMCW radar is used for the various purposes in the short range detection and tracking of targets. The main advantages of a FMCWradar are the comparative simplicity of implementation and the low peak power transmission characterizing the very low probability of signal interception. Since it uses the frequency modulated continuous wave for transmission and demodulation, the received beat frequency represents the range and Doppler information of targets. Detection and extraction of useful information from targets are performed in this beat frequency domain. Therefore, the resolution and accuracy in the estimation of a beat spectrum are very important. However, using the conventional FFT estimation method, the high resolution spectrum estimation with a low sidelobe level is not possible if the acquisition time is very short in receiving target echoes. This kind of problems deteriorates the detection performance of adjacent targets having the large magnitude differences in return echoes and also degrades the reliability of the extracted information. Therefore, in this paper, the model parameter estimation methods such as autoregressive and eigenvector spectrum estimation are applied to mitigate these problems. Also, simulation results are compared and analyzed for further improvement.

• The Korean Journal of Archival Studies
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• no.66
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• pp.203-227
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• 2020

This article explores the influence of the king in the Joseon dynasty's document transmission system, focusing on some exceptional cases. According to the Joseon's law, the form of official documents depended on rank differences between receiver and sender. However, there were cases of not following the general principles such as Byungjo(兵曹), Seungjeongwon(承政院) and Kyujanggak(奎章閣). Byungjo was a ministry in charge of military administration. Seungjeongwon was a royal secretary institution which assisted the king and delivered king's orders that existed from the early Joseon. Kyujanggak was a royal library and an assistant institution of the king that was established in the JeongJo(正祖) era. Byungjo was regarded as a relatively high-ranking institution when it sent and received military-related documents. Seungjeongwon and Kyujanggak could use Kwanmoon(關文) to upper rank institution. Kwanmoon was the document form used for institutions of the same or lower rank than itself. Conversely, higher rank institutions used Cheobjeong(牒呈) which was stipulated as a document form to using upper rank institution in law to send them. The reason that they could have privileges in transmission document system was that Joseon had an administrative system centered on the king. Byungjo was an institution entrusted with military power from King. Seungjeonwon and Kyujanggak took charge of the assistance and the delivery of King's order. so they could have a different system of receiving and sending document than the others. In conclusion, the Joseon Dynasty operated exceptions in document administration based on the existence of the king, it means Joseon's transmission document system was basically operated under the Confucian bureaucracy with the king as its peak.

• Resources Recycling
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• v.19 no.6
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• pp.43-50
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• 2010

The crisis of energy gives rise to the growing concerns over continuing uncertainty in the energy market. Under these circumstances, there are also increasing interests on coals. In particular, Low Rank Coal (LRC) is receiving gradual attentions from green industry. But due to is high moisture content range from 30 - 60%, drying process has to be preceded before being utilized as power plant. In this study drying kinetics of LRC is induced by using a fixed-bed reactor. The drying kinetics was evaluated in from of the particle size, the inlet gas temperature, the drying time, the gas velocity, and the LID ratio. The consideration of the reynold's number was taken for correction of gas velocity, particle size and LID was taken for correction of reactor diameter, packing height of coal. As being seen as characteristic of drying coal, it can be found that fixed-bed reactor can contributed to active drying of free water. In this sense, it could be considered that phase boundary reaction is appropriate mechanism.

• Journal of agricultural medicine and community health
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• v.46 no.4
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• pp.230-241
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• 2021

Objectives: The purpose of this study was to identify the level of quality of life and related factors in the elderly with dementia living in their houses of rural area who are receiving dementia partners' supporting activities. Methods: The study participants were 55 elderly people with dementia living in their houses who were participating in the dementia partner pilot project among those registered in the public health center in one area and 55 dementia partners. Data were analyzed by independent t-test, ANOVA, Pearson correlation analysis and multiple regression analysis. Results: The factors that had a significant effect on quality of life included depression to predict the quality of life in the elderly with dementia. And its explanatory power was 46.8%. Conclusions: Based on these results, it is crucial not only to maintain physical functions but also to decrease depression by emotional support activities so as to enhance their quality of life, therefore, it is required to develop and apply the integrative supporting programs in rural area. From the result that dementia partner's self-compassion would lower the depression in the elderly with dementia significantly, it is considered to develop the programs to enhance dementia partners' self-compassion.

• Journal of Adhesion and Interface
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• v.22 no.1
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• pp.1-7
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• 2021

The importance of high capacity energy storage devices has recently emerged for stable power supply through renewable energy generation. From this point of view, the Na-air battery (NAB), which is a next-generation secondary battery, is receiving huge attention because it can realize a high capacity through abundant and inexpensive raw materials. In this study, activated carbon-based catalysts for hybrid type Na-air batteries were prepared and their characteristics were compared and analysed. In particular, from the viewpoint of resource recycling, activated carbon (Orange-C) was prepared using discarded orange peel, and performance was compared with Vulcan carbon, which is widely used. In addition, a Pt/C catalyst (homemade-Pt/C, HM-Pt/C) was synthesized using a modified polyol method to check whether the prepared activated carbon can be used as a supported catalyst, and a commercial Pt/C catalyst (Commercial Pt/C) and electrochemical performance were compared. The prepared Orange-C exhibited a typical H3 type BET isotherm, which is evidence that micropore and mesopore exist. In addition, in the case of HM-Pt/C, it was confirmed through TEM analysis that Pt particles were evenly distributed on the activated carbon supported catalyst. In particular, the HM-Pt/C-based NAB showed the smallest voltage gap (0.224V) and good voltage efficiency (92.34%) in the 1st galvanostatic charge-discharge test. In addition, the cycle performance test conducted for 20 cycles showed the most stable performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.472-482
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• 2019

This paper describes the stabilization of underwater TAS winch system Deploy/Recover operation performance. TAS winch installed on the stern of submarine performs to deploy/recover sensor, towing cable and rope tail which is deployed from the stern and separated from submarine itself. Also TAS winch provides transmission path of power to the sensor and data transmitting/receiving path which data are acquired from underwater environment like sound, depth and temperature. At the step of TAS winch evaluation test, sporadic standstill and rotating speed oscillation phenomenon were occurred. Winch motor provides the available torque to deploy/recover TAS and root cause analysis to the winch motor was done to find exact reason to sporadic malfunction. When winch motor was disassembled, eccentricity of rotor, slip-ring and the other composition part for winch motor were found. These might cause magnetic field distortion. To make TAS winch system more stable and block magnetic field distortion, this paper suggests methods to enhance fixing status installed in winch motor. For reliable data acquisition for TAS winch operation, the deploy/recover function of the improved type of TAS winch was verified in LBTS making similar condition with sea status. At the end of stage, improved type of TAS winch was tested on some functions not only deploy/recover function, but sustainability of TAS operation on specific velocity, steering angle of submarine in the sea trial. Improved type of TAS winch was verified in accordance with design requirement. Also, validity of suggested methods were verified by the sea trial.

• Journal of Advanced Navigation Technology
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• v.23 no.2
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• pp.151-157
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• 2019

In geostationary satellite communications, which are widely used for broadcasting and communication, there is a path loss where the signal power on the path is largely reduced. It is important to consider rain attenuation when calculating link budget because the Ka band frequency is vulnerable to rain attenuation. In this study, rainfall trends were analyzed by using rainfall data from the year 2000 in four regions of Korea (Seoul, Incheon, Busan, Jeju) and the rainfall attenuation was calculated. This was used to analyse the satellite link budget and receiving performance for the down-link of the korea satellite COMS. In this study, the calculated G/T for the rainfall intensity of 0.5% per year using the rainfall data for 18 years increased by approximately $8.5dBK^{-1}$ compared to the ITU's zone-K rain model, and decreased by approximately $1dBK^{-1}$ compared to the precipitation data for 13 years from the TTA(Korea Telecommunications Technology Association). The results of this study can be used for the design of G/T in domestic-installed satellite ground station.