• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.596-601
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• 2020

Silicon carbide is considered a potentially useful material for high-temperature electronic devices because of its large band gap energy and p-type or n-type conduction that can be controlled by impurity doping. Accordingly, the thermoelectric properties of -SiC powder prepared by refined diatomite were investigated for high value-added applications of natural diatomite. -SiC powder was synthesized by a carbothermal reduction of the SiO₂ in refined diatomite using carbon black. An acid-treatment process was then performed to eliminate the remaining impurities (Fe, Ca, etc.). n-Type semiconductors were fabricated by sintering the pressed powder at 2000℃ for 1~5h in an N2 atmosphere. The electrical conductivity increased with increasing sintering time, which might be due to an increase in carrier concentration and improvement in grain-to-grain connectivity. The carrier compensation effect caused by the remaining acceptor impurities (Al, etc.) in the obtained -SiC had a deleterious influence on the electrical conductivity. The absolute value of the Seebeck coefficient increased with increasing sintering time, which might be due to a decrease in the stacking fault density accompanied by grain or crystallite growth. On the other hand, the power factor, which reflects the thermoelectric conversion efficiency of the present work, was slightly lower than that of the porous SiC semiconductors fabricated by conventional high-purity -SiC powder, it can be stated that the thermoelectric properties could be improved further by precise control of an acid-treatment process.

• The Journal of Korean Medicine
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• v.31 no.5
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• pp.1-11
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• 2010

Objectives: This study aimed to evaluate any clinical studies regarding rhinitis published by the Korean Oriental Medical Society and its sub-societies for future rigorous clinical research. Methods: Every article relevant to rhinitis was initially obtained from journals of the Korean Oriental Medical Society and its sub-societies by electronic search at journal web sites or manual searches. Journals were limited to those registered with the Korea Research Foundation. From initial findings, two independent reviewers selected clinical articles and these articles were further analyzed separately by predefined criteria according to prospective and retrospective studies. For prospective studies, quality assessment was also conducted. Results: From 36 initially obtained articles, 17 were finally analyzed. 2 articles were randomized controlled studies, 6 articles were prospective whereas 9 were retrospective. In the prospective articles, there were no randomized controlled trials and the other non-randomized studies had no control group with several problems of quality regarding pre-calculated study size and unbiased assessment. None of the retrospective studies described rhinitis diagnosis objectively and outcome measures were either non-relevant to rhinitis or non-validated. Conclusions: Further well-designed randomized controlled studies for rhinitis are mandatory and more rigorous non-randomized controlled studies should be conducted.

• Journal of Hospice and Palliative Care
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• v.21 no.3
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• pp.84-91
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• 2018

Purpose: This study aims to investigate treatment of cancer patients at a secondary hospital. Methods: A retrospective analysis was performed with electronic medical records of cancer patients admitted to a secondary hospital from January 1, 2009 through September 31, 2017. Results: A total of 223 patients were studied. Sixty-nine patients were hospitalized for supportive care after receiving a surgery, chemotherapy, and radiotherapy at a tertiary hospital, 58 patients for other supportive care, 53 patients for symptom control, 16 patients with a decision not to take active cancer treatment, and 27 patients for treatment of cancer that was diagnosed during their hospital stay. Among 75 patients who were discharged to other institutions, 50 were transferred to tertiary hospitals, 10 to long-term care hospitals, eight to hospice hospitals, four to nursing homes and two to secondary hospitals. Comorbidities were found in 120 patients (53.8%). For patients who consulted with more than one department, more consultations were for non-cancer diseases than cancer. Seventy-three patients had a do-not-resuscitate order. Conclusion: For treatment of cancer patients, it is needed to establish a cooperation system among medical institutions and provide comprehensive management including treatment of comorbidities.

• Biomolecules & Therapeutics
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• v.20 no.2
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• pp.226-233
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• 2012

Ethanol exposure during gestational period is related to growth retardation, morphological abnormality, and even in neurological abnormalities including attention deficit/hyperactivity disorder (ADHD)-like behaviors on offspring. However, relatively little is known about the effects of maternal ethanol consumption prior to conception on their offspring. In this study, we investigated whether maternal ethanol administration during preconceptional phase produces ADHD-like behaviors in the rat offspring. Sprague-Dawley (SD) female rats were administrated ethanol via intragastric intubation with dosing regimen of 6 g/kg daily for 10 consecutive days and treated female rats then mated with non-treated male SD rats after 8 weeks. Another group subjected to the same procedure as those conducted on ethanol treated group except the saline administration instead of ethanol. Offspring was tested for their ADHD-like behaviors using open field test, Y maze test and impulsivity test that is performed in the aversive electronic foot shock paradigm. Offspring of preconceptional ethanol treated (EtOH) group showed hyperlocomotive activity, attention deficit and impulsivity. And reduction of striatal dopamine transporter (DAT) level was observed by Western blot in the EtOH group, compared to control (Con) group, while the immunohistochemical analysis exhibited increased expression of norepinephrine transporter (NET) in the frontal cortex. These results suggest that maternal ethanol consumption in the preconceptional phase induces ADHD-like behaviors in offspring that might be related to the abnormal expression of DAT and NET in rat.

• Horticultural Science & Technology
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• v.30 no.4
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• pp.371-377
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• 2012

This study was conducted to investigate the physiological and structural damages to cadmium (Cd) in Acorus calamus var. angustatus as a native aquatic species in Korea. In addition to the physiological responses such as plant growth, photosynthesis, and root activity, the structural damages in leaf and root tissues were observed through light and scanning electronic microscopy. The five-leaf plants were treated with different Cd concentrations 0, 10, 25, and 50 ${\mu}M$ for 15 days. The plant damages to Cd were significant at 10-25 ${\mu}M$ Cd physiologically and at 25-50 ${\mu}M$ Cd structurally. The physiological damages in the shoot part (photosynthesis) started at 10 ${\mu}M$ Cd whereas those in root part (root activity) were serious above 25 ${\mu}M$ Cd. On the other hand, the structural damages began at 25 ${\mu}M$ Cd in the leaf and root tissues similarly, but the plant tissue destruction was more serious in the roots than in leaves. Based on the plant physiological and structural damages, 10 ${\mu}M$ was assumed to be the limited concentration for sustainable growth and landscaping ability in Acorus calamus var. angustatus to Cd.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.527-531
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• 2006

We have prepared organophilic inorganic particles and polyimide (PI) nanocomposite having excellent thermal stability and high dielectric constant that can be used for electronic application such as capacitor. We have chosen barium titanate (BT), a high dielectric constantmaterial and its surface was coated with nylon 6 to improve the affinity with PI. The FT-IR and TEM studies showed that the organophilic inorganic particle (BTN) has a polymer shell with thickness of 5 nm. We have suggested that it is possible to control the thickness of coating surface and also indicated the relationship between the ratio of inside and outside radius of BTN and the weight fraction of BT. The PI nanocomposite films based on poly(amic acid) and BTN were prepared by cyclodehydration reaction. The homogeneous dispersion of BTN in PI matrix was identified by using SEM. We have investigated the effect of BTN content on the coefficient of thermal stability, integral procedural decomposition temperature (IPDT), and dielectric constant of PI nanocomposite films.

• Journal of Digital Contents Society
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• v.17 no.2
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• pp.71-79
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• 2016

This study is intended to compare the performances of sound source localization methods used for stable automobile control by improving voice recognition rate in automobile environment and suggest how to improve their performances. Generally, sound source location estimation methods employ the TDOA algorithm, and there are two ways for it; one is to use a cross correlation function in the time domain, and the other is GCC-PHAT calculated in the frequency domain. Among these ways, GCC-PHAT is known to have stronger characteristics against echo and noise than the cross correlation function. This study compared the performances of the two methods above in automobile environment full of echo and vibration noise and suggested the use of a median filter additionally. We found that median filter helps both estimation methods have good performances and variance values to be decreased. According to the experimental results, there is almost no difference in the two methods' performances in the experiment using voice; however, using the signal of a song, GCC-PHAT is 10% more excellent than the cross correlation function in terms of the recognition rate. Also, when the median filter was added, the cross correlation function's recognition rate could be improved up to 11%. And in regarding to variance values, both methods showed stable performances.

• Journal of Service Research and Studies
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• v.6 no.1
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• pp.1-15
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• 2016

The purpose of this study is to suggest strategic approach to expand Korean e-government export. Korean e-government was evaluated as a top level by UN electronic government survey 2014. However its export is very limited. This study reviews the literature related to e-government, and analyze existing Korean e-government export. The results of this analysis are as follows: lack of a law related e-government export, decentralized organizations, insufficient export process, lack of e-government solution for sale, limited funds, deficiency of cooperation between large and small enterprises. This study suggests a strategic approach such as to clarify the purpose of e-government export, to decide government or civilian-oriented export, to establish driving strategy, to improve and develop e-government export related areas. There are many ways for improvement and development of e-government export as follows: to enact a basic law or to revise the e-government law, to integrate functions of separated organizations and establish control tower, to improve export process, to build information sharing system, to develop standardized solution module, and to expand fund to support. The author expects that this paper will contribute to enhance Korean e-government export.

• Food Science and Preservation
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• v.23 no.6
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• pp.848-858
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• 2016

This study was conducted to determine the $F_0$-values of a retort machine at different locations and to evaluate the effects of these $F_0$-values on various quality characteristics of retorted Samgyetang samples. Samples were divided into three groups based on $F_0$-values-T1, 10~20; T2, 20~30; T3, >30. Mineral content in Samgyetang broth and breast meat mostly increased with increasing $F_0$-values. In general, the free amino acid values, hardness, and springiness, except for bone springiness, of Samgyetang decreased significantly at higher $F_0$-values. Protein content of meat and broth of the treated samples were significantly lower than that of the control. An increase in the digestion rate of meat and porridge, as well as the turbidity of the broth was observed in most of the treated samples with increasing $F_0$-values. With increasing $F_0$-values, the $L^*$ and $b^*$ values of meat and the $b^*$ values of broth tended to increase, while the $a^*$ value of broth increased significantly. Electronic nose analysis revealed different flavor patterns for samples treated at different $F_0$-values. For sensory traits, samples treated with higher $F_0$-values tended to receive lower evaluations. Particularly, the color and texture of T3 samples were lower than those of T1 and T2 samples. In conclusion, to improve the quality of Samgyetang, the efficiency and optimization of retort machines as well as the standardization of sterilization techniques are needed.

• Korean Journal of Optics and Photonics
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• v.17 no.3
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• pp.278-284
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• 2006

We have fabricated and measured electrooptic modulator using coupled stack InAs/InGaAs quantum dots. The height of the quantum dot is 16 nm and quantum dots are stacked including an InGaAs capping layer. The peak wavelength of photoluminescence is 1260 nm at room temperature and 1158 nm at 12 K. The operation characteristics of the quantum dots show high modulation efficiency of electrooptic modulator at 1550 nm compared to that of existing III-V bulk and MQW type semiconductor. The measured switching voltage ($V\pi$) is 540 and 600 mV, for TE mode and TM mode, respectively. From the results, the modulation efficiency can be determined as 333.3 and $300^{\circ}/V{\cdot}mm$ for TE and TM modes. The results reported here may lead to the design and fabrication of a novel electrooptic modulator with low switching voltage and high efficiency.