• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.495-500
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• 2007

The inside wall of a coal gasifier is lined with refractory, and the corrosion of the refractory is an important factor affecting the refractory lifetime and the replacement period. This paper examines the changes in microstructure of a chromia refractory due to chemical reactions with slag having varying amounts of $Fe_2O_3$. Slag samples were prepared by adding $Fe_2O_3$ to KIDECO slag, and static corrosion experiments were carried out at $1550^{\circ}C$. The layer of $(Fe,Cr)_3O_4$ formation and the depth of Fe depletion in the infiltrating slag were determined. In addition, FactSage equilibrium calculations were carried out in order to determine the conditions of formation, and to compare with the experimental observations. In the sample exposed to KIDECO slag, which has about 10 wt% $Fe_2O_3$, the formation of $(Fe,Cr)_3O_4$ was not observed. As the $Fe_2O_3$ concentration in slag increased, $(Fe,Cr)_3O_4$ formation and Fe depletion depth increased. Increasing $Fe_2O_3$ concentration also made the slag/refractory interface indistinguishable. Equilibrium calculations predicted that higher $Fe_2O_3$ concentrations favor chromite formation at gasification temperatures. The chromite formation was most favorable when the amount of $Cr_2O_3$ was limited, as in the case of dissolved $Cr_2O_3$ in slag. When the concentration of $Fe_2O_3$ in slag was less than 20%, the formation of chromite was least favorable in the system with equal amounts of slag and refractory.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.1 s.38
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• pp.7-15
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• 2006

In-situ observation of electromigration in thin film pattern of 63Sn-37Pb solder was performed using a scanning electron microscope system. The 63Sn-37Pb solder had the incubation stage of electromigration for edge movement when the current density of $6.0{\times}10^{4}A/cm^2$ was applied the temperature between $90^{\circ}C\;and\;110^{\circ}C$. The major diffusion elements due to electromigration were Pb and Sn at temperatures of $90-110^{\circ}C\;and\;25-50^{\circ}C$, respectively, while no major diffusion of any element due to electromigration was detected when the test temperature was $70^{\circ}C$. The reason was that both the elements of Sn and Pb were migrated simultaneously under such a stress condition. The existence of the incubation stage was observed due to Pb migration before Sn migration at $90-110^{\circ}C$. Electromigration behavior of 63Sn-37Pb solder had an incubation time in common for edge drift and void nucleation, which seemed to be related the lifetime of flip chip solder bump. Diffusivity with $Z^*$(effective charges number) of Pb and Sn were strongly affect the electromigration-induced major diffusion element in SnPb solder by temperature, respectively.

• (The)Study of the Eastern Classic
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• no.69
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• pp.509-530
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• 2017

The purpose f this thesis is to examine the reality of Min Sha-pyeong, which led to life in the end of the Koryo Dynasty. Min Sha-pyeong was able to conduct academic exchanges through active negotiations with various scholars at the time. After passing the civil service exam at the age of 21, Min Sha-pyeong acted in various positions and remained loyal to the government. Min Sha-pyeong, who frequently met with Lee Je-hyun, Baek Mun-bo and Lee-saek, exchanged opinions. Sometimes Baek Mun-bo gathered together and always joined him when drinking. Lee-saek was convinced that his poetry would continue to inspire. The time when Min Sha-pyeong was active very confusing at home and abroad. In the end of the Koryo Dynasty, the national operating system was unstable due to the poor land and the suffering of the afflicted people, who suffered from frequent in vasions of Japan. At the time, the corruption and the suffering of the people were serious. Min Sha-pyeong refers to the reality of the people who love the people, reflecting the lives of the people living in poverty. Min Sha-pyeong thinks life without loyality is not a normal life. If I had a desire, I realized that the riches of wealth would wane someday. Min Sha-pyeong hoped that he would be relieved of his sympathy and would be relieved of their position in sympathy ith the people. Here, youy can see the reality of the people in Min Sha-pyeong is clearly revealed.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1085-1092
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• 2001

The high efficient AC powder EL devices classified by low cost and low power consumption type fabricated using screen printing method with film thickness and organic binder. Brightness and current density were measured at frequency range of 400Hz∼1kHz and voltage range of 50∼300V$\_$rms/ to estimate optoelectrical properties of AC powder EL devices, respectively. Frequency generator was used as system producing frequency and voltage of a sine wave. Also brightness and current density were measured by luminometer and multimeter. In the case of low cost type AC powder EL device, brightness and current density were about 43 cd/m$^2$and 20$\mu$A/cm$^2$when the thickness of phosphor and dielectric layer was 45∼50$\mu$m under no addition of plasticizer respectively. In the case of low power consumption type AC powder EL device, brightness and current density were about 74 cd/m$^2$and 30∼40$\mu$A/cm$^2$when the thickness of phosphor and dielectric layer was 45∼50$\mu$m and 15∼20$\mu$m under addition of 15wt% plasticizer respectively. Also, AC powder EL device fabricated in this study showed absolutely excellent characteristics as the lifetime was longer than products of other company.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3472-3480
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• 2010

The Clustering technology of Energy efficiency wireless sensor network gets the energy efficiency by reducing the number of communication between sensor nodes and sink node. In this paper, First analyzed on the clustering technique of the distributed clustering protocol routing scheme LEACH (Low Energy Adaptive Clustering Hierarchy) and HEED (Hybrid, Energy-Efficient Distributed Clustering Approach), and based on this, new energy-efficient clustering technique is proposed for the cause the maximum delay of dead nodes and to increase the lifetime of the network. In the proposed method, the cluster head is elect the optimal efficiency node based on the residual energy information of each member node and located information between sink node and cluster node, and elected a node in the cluster head since the data transfer process from the data been sent to the sink node to form a network by sending the energy consumption of individual nodes evenly to increase the network's entire life is the purpose of this study. To verify the performance of the proposed method through simulation and compared with existing clustering techniques. As a result, compared to the existing method of the network life cycle is approximately 5-10% improvement could be confirmed.

• Journal of the Daesoon Academy of Sciences
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• v.49
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• pp.127-156
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• 2024

The purpose of this study is to examine the influence of the village gut (shamanic ritual) Dangsanje and Nong-ak (agricultural musical ritual) in the Jeong-eup Province on the formation of the ideology of the Jeungsan (甑山), Kang Il-sun (姜一淳 1871~1909), a thinker from Jeong-eup. As a result, this article has reached the following conclusions: first, the ideas of a certain thinker are influenced by the local culture in which they were born and raised. Second, the central area where Kang Jeungsan was born, grew up, and later developed his system of philosophical thought was the Jeong-eup Province. Third, in Jeong-eup, Nong-ak is traditionally accompanied as a necessary requirement. Fourth, the Nong-ak that Kang Jeungsan witnessed in his hometown during his lifetime had those qualities. Fifth, Kang Jeungsan empirically identified the close interrelationship between Village Gut Dangsanje, Nong-ak, and Mudanggut from an early age. Sixth, this aspect of influence is tangibly reflected in the words and actions he left behind. Seventh, Kang Jeungsan's experience of Jeong-eup Nong-ak was recreated in the religious music of Bocheonism, where his ideas were formulated into an organized religion for the first time. Eighth, this process of religionizing Nong-ak in Bocheonism greatly influenced later Jeong-eup Nong-ak and also Honam Nong-ak more generally.

• Journal of dental hygiene science
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• v.11 no.3
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• pp.189-197
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• 2011

Objectives : The systematic health education to form the basic healthy lifestyle should be realized from elementary school, so oral health education at elementary school can determine the whole lifetime oral health. The elementary school health teacher's recognition and behavior who in charge of health promotion of students is important. Therefore, the study was conducted to enhance oral health education. Methods : Total 114 people among of 131 from health teacher Gwangju elementary school. Survey system is configured by referring to PRECEDE model. Results : In behavioral diagnosis the proportion of oral Health Education is less than 10%(58.8%), mostly educated in activity time (86.0%), the health teachers educate when it is needed(53.5%). In predisposing diagnosis in the eight areas of health education, the oral health education is ranked as fourth, fifth. Even in the next year project, the oral health education ratio was 21.9 percent. In enabling diagnosing every year the Oral health education training experienced rate is 13.2%, satisfaction rate is 33.3%. In reinforcing diagnosing disability element in the regular education course are the lack of oral health-related information (46.7%), lack of materials needed for education (30.6%), lack of training opportunities (21.4%). Conclusion : In further research, oral health education textbooks, materials and methods should be developed. At the foundation of there developments, the elementary oral health education program should be more fully developed and conducted and also the evaluation of its effectiveness will need.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.7
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• pp.754-759
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• 2015

Nowadays, short distance communication systems with low power energy (LPE) are developed for identification and monitoring of site identification of vessel crews and passengers (SIVCP). LPE communication modules, such as Bluetooth low energy (BLE) and Zigbee, are used for short distance communications with LPE. These modules enable 1:N communications and their popularity is growing since the modules can be mounted on movable objects, such as mobile devices and human body. When these modules are used, the important factor that affects their operation time and design are the capacity and size of battery. Therefore, they must be made as small as possible, and the battery should be selected to be slightly smaller than the module. In this study, we calculate the theoretical life of batteries used in SIVCP BLE modules using data sheet and discharge characteristic graph under the condition of a 1/250 transmission-ratio (TR). We thus calculate experimental life by measuring transmission current for the same TR, and low speed mode current for a 1/5000 TR and measure long-term experimental life using 1/25 TR for days. Through these experiments, we verify experimental methods for the prediction and extension of battery life that would enable us to select appropriate sizes of batteries based on vessel usage and passenger types. The selections of the module TR and battery size are important factors affecting the cost reduction of module design, the battery maintenance, and passenger convenience.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.535-545
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• 2019

The PBA of ship weapon system should be installed and operated under harsh environmental conditions and so it should be highly reliable to endure the mission profiles during its entire lifetime. In the case of PBA failure during operation, rapid maintenance is highly likely to be difficult due to problems such as supply of parts, which can have a devastating effect on the mission. In order to validate the reliability of PBA, a series of tests are performed with PBA samples, but they require time, testing facilities, samples, expenses and failure analysis if failed. The reliability of PBA is predicted on the basis of specifications such as MIL-HDBK-217F, but this specification does not take into account failure mechanisms for specific design details, environment and usage, interconnects and its characteristics that drive many failures of PBA in the field. Therefore, this study predicts the reliability of PBA using an RPA tool and proposes the RPA methodology as a validation process at the design stage. With RPA, it is now possible to achieve design validation including inherent failure mechanism, identification of weakest link, alternative design options, and test plan development.

• Korean Journal of Optics and Photonics
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• v.9 no.4
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• pp.221-226
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• 1998

Ternary heavy metal oxide glasses in the $PbO-Bi_2O_3-Ga_2O_3$ system doped with $Er_2O_3$ were prepared and their spectroscopic properties, such as radiative transition probability, calculated and measured radiative lifetimes and cross-sections of 1.5 $\mu\textrm{m}$ and 2.7 $\mu\textrm{m}$ emissions were analyzed. Enhanced quantum efficiencies of some electronic transitions were evident mainly because of the low vibrational phonon energy ($~500cm^{-1}$) inherent in the host glasses. This seems to be the main reason for obtaining the 2.7 $\mu\textrm{m}$ luminescence which is normally quenched in the conventional oxide glasses. In addition, green and red fluorescence emissions were observed through the frequency upconversion processes of the 798 nm excitation. Non-radiative transition due to the multiphonon relaxation is a dominant lifetime-shortening mechanism in the 4f-4f transitions in $Er^{3+}$ ion except for the $^4S_{3/2}{\rightarrow}^4I_{15/2}$ transition where a non-radiative transfer to band-gap excitation of the host glasses is dominant. Melting of glasses under an inert gas atmosphere and (or) addition of the typical glass-network former into glasses is necessary in order to enhance the quantum efficiency of the transition.