• The Korean Journal of Physiology
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• v.26 no.2
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• pp.113-122
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• 1992

It is well known that chromaffin cells of adrenal medulla secrete catecholamine in response to sympathetic nerve activation and the influx of $Ca^{2+}$ through the voltage dependent $Ca^{2+}$ channels (VDCC) in the cell membrane do a major role in this secretory process. In this study, we explored the effect of divalent cations on VDCC of rat chromaffin cells. Rat (Sprague-Dawley rat, 150-250 gm) chromaffin cells were isolated and cultured. Standard giga seal, whole cell recording techniques were employed to study $Ca^{2+}$ current with external and internal solutions that could effectively isolate VDCC currents $(NMG\;in\;external\;and\;TEA\;and\;Cs^{2+}\;in\;internal\;solution)$. The voltage dependence and the inactivation time course of VDCC in our cells were identical to those of bovine chromaffin cells. A persistent inward current was first activated by depolarizing step pulse from the holding potential (H.P.) of -80 mV to -40 mV, increased to maximum amplitude at around +10 mV, and became smaller with progressively higher depolarizing pulses to reverse at around +60 mV. The inactivation time constant $(\tau)$, fitted from the long duration test potential (2 sec) was $1295.2{\pm}126.8$ msec $(n=20,\;1\;day\;of\;culture,\;mean\;{\pm}S.E.M.)$ and the kinetic parameters were not altered along the culture duration. Nicardipine $(10\;{\mu}M)$ blocked the current almost completely. Among treated divalent cations such as $Cd^{2+},\;Co^{2+},\;Ni^{2+},\;Zn^{2+}\;and\;,Mn^{2+},\;Cd^{2+}$ was the most potent blocker on VDCC. When the depolarizing step pulse from -80 mV to 10 mV was applied, the equilibrium dissociation constant $(K_d)$ of $Cd^{2+}\;was\;39\;{\mu}M,\;K_d\;of\;Co^{2+}\;was\;100\;{\mu}M\;and\;K_d\;of\;Ni^{2+}];was];780{\mu}M.$ The principal findings of this study are as follows. First, the majority of $Ca^{2+}$ channels in rat chromaffin cells are well classified to L-type $Ca^{2+}$ channel in the view of kinetics and pharmacology. Second, all divalent cations tested could block the $Ca^{2+}$ current and the most potent blocker among the tested was $Cd^{2+}$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.3
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• pp.275-284
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• 2006

In the measurement of gamma rays emitted from the nuclide in the radioactive waste drum, to analyze the nuclide concentration accurately, it is necessary to use the proper calibration standards and to correct for the attenuation of the gamma rays. Two drums having a different density were used to analyze the nuclide concentration inside the drum in this study. After carrying out the system calibration, we measured the gamma rays emitted from the standard source inside the model drum with changing the distance between the drum and the detector. The measured values were corrected with the three kinds of gamma attenuation correction methode, as a results, the error was less than 10 % in the low density drum and less than 25 % in the high density drum. The measured activity in the short distance was more accruable than in the long distance. The transmission correction for the mass attenuation showed good results(very Low error) compared to the mean density and the differential peak correction method.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.235-242
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• 2018

The interest about 4th Industrial Revolution was impressively increased from newspapers, iindustry, government and academic sectors. Especially AI what could be felt by the skin of many peoples, already overpassed the ability of the human's even in creative areas. Namely, now many people start fo feel that the effect of the revolution is just infront of themselves. There were several issues in this trend, the ability of deep learning by machine, the identity of the human, the change of job environment and the concern about the social change etc. Recently many studies have been made about the 4th industrial revolution in many fields like as AI(artificial intelligence), CRISPR, big data and driverless car etc. As many positive effects and pessimistic effects are existed at the same time and many preventing actions are being suggested recently, these opinions will be compared and analyzed and better solutions will be found eventually. Several educational, political, scientific, social and ethical effects and solutions were studied and suggested in this study. Clear implication from the study is that the world we will live from now on is changing faster than ever in the social, industrial, political and educational environment. If it will reform the social systems according to those changes, a society (nation or government) will grasp the chance of its development or take-off, otherwise, it will consume the resources ineffectively and lose the competition as a whole society. But the method of that reform is not that apparent in many aspects as the revolution is progressing currently and its definition should be made whether in industrial or scientific aspect. The person or nation who will define it will have the advantage of leading the future of that business or society.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.301-312
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• 2018

The purpose of this study is to propose strategies for enhancing competitiveness through the utilization of policy funds, especially in the start-up companies supported by the Korea Credit Guarantee Fund. And then, the Korea Credit Guarantee Fund should develop 'user-centered policy funding model' in order to increase start-up's utilization of policy fund and support start-ups that are supported in the long run. The competitiveness of domestic start-up companies has been strengthened by 'user-centered policy funding model' and new innovations have been introduced through 'Living Lab', an open innovation. But, in order to overcome the limitation of reaching the stage of commercialization, the 'user-centered policy funding model' proposed in this study enables start-ups to be the subject of actual policy funding, and also allows users to freely apply for necessary funding at any time. Therefore, the Korea Credit Guarantee Fund has a significance in suggesting 'user-centered policy funding model' as a support model to be customized. However, since SMEs recognize the actual situation and limit acceptance of all the difficulties, the systematic analysis of the actual situation of the policy funds of the start-up by the credit guarantee fund and the related support institutions for the scientific approach of the user-oriented policy funding model need.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.4
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• pp.231-239
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• 2012

Objectives: This study sought to provide guidelines in order to decrease the incidence of nerve injury during mandibular ramus bone harvesting, and to improve understanding of the anatomical structure of the inferior alveolar canal (IAC) to include its distance from the exterior buccal cortex. Materials and Methods: In January and February 2009, 20 patients who visited the Wonkwang University Department of Oral and Maxillofacial Surgery reporting various conditions underwent cone beam computed tomography and were included in this study. Patients with missing left or right mandibular first molars or incisors, or who had jaw fracture or bone pathologies, were excluded. The reference point (R point) was defined as the point where the occlusal plane reached the anterior ramus of the mandible. The position of the IAC in relation to the R point, the buccal bone width (BW), the alveolar crest distance (ACD), the distance from the alveolar crest to the occlusal plane (COD), and the distance from the IAC to the sagittal plane (CS) were determined using proprietary image analysis software which produced cross-sectional coronal and axial images. Results: The distance medially from the R point to the IAC along the axial plane was $6.19{\pm}1.21mm$. The HD from the R point, posteriorly to IAC, in the lateral view was $13.07{\pm}2.45mm$, the VD from the R point was $14.24{\pm}2.41mm$, and the ND from the R point was $10.12{\pm}1.76mm$. The pathway of the IAC was positioned almost in a straight line along a sagittal plane within $0.56{\pm}0.70mm$. The distance from the buccal bone surface to the IAC increased anteriorly from the R point. Conclusion: Marking osteotomy lines in the retromolar area in procedures involving bone harvesting should be discouraged due to the risk of damage to IAC structures. Our measurements indicated that the area from the R point in the ramus of the mandible to 10 mm anterior can be safely harvested for bone grafting purposes.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.619-625
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• 2008

The effects of thermal cycling on residual stresses in both inorganic passivation/insulating layer that is deposited by plasma enhanced chemical vapor deposition (PECVD) and organic thin film that is used as a bonding adhesive are evaluated by 4 point bending method and wafer curvature method. $SiO_2/SiN_x$ and BCB (Benzocyclobutene) are used as inorganic and organic layers, respectively. A model about the effect of thermal cycling on residual stress and bond strength (Strain energy release rate), $G_c$, at the interface between inorganic thin film and organic adhesive is developed. In thermal cycling experiments conducted between $25^{\circ}C$ and either $350^{\circ}C$ or $400^{\circ}C$, $G_c$ at the interface between BCB and PECVD $ SiN_x $ decreases after the first cycle. This trend in $G_c$ agreed well with the prediction based on our model that the increase in residual tensile stress within the $SiN_x$ layer after thermal cycling leads to the decrease in $G_c$. This result is compared with that obtained for the interface between BCB and PECVD $SiO_2$, where the relaxation in residual compressive stress within the $SiO_2$ induces an increase in $G_c$. These opposite trends in $G_cs$ of the structures including either PECVD $ SiN_x $ or PECVD $SiO_2$ are caused by reactions in the hydrogen-bonded chemical structure of the PECVD layers, followed by desorption of water.

• Journal of Convergence for Information Technology
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• v.10 no.5
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• pp.157-167
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• 2020

The purpose of this study was to identify the factors affecting job satisfaction in dental hygienists with and without schoolwork, who form professional manpower in dental clinics, and provide basic data that could help develop detailed plans for reducing the turnover intention and improving job satisfaction. For data collection, convenience sampling was performed among clinical dental hygienists at dental clinics in Daejeon and Chungcheong and Gyeongsang Provinces from July 20 to September 20, 2019, and a self-administered questionnaire was used and the data were analyzed by T-test, One-way Anova, Pearson correlation, Stepwise multiple regression analysis, etc. using IBM SPSS/WIN 20.0. For the dental hygienists with schoolwork, job stress was negatively correlated with professional self-concept and job satisfaction, and professional self-concept was positively correlated with job satisfaction; for the dental hygienists without schoolwork, job stress was negatively correlated with professional self-concept and job satisfaction, and professional self-concept was positively correlated with job satisfaction. The factors affecting job satisfaction were professional self-concept, job stress, and age of ≥30 for the dental hygienists with schoolwork and professional self-concept, job stress, and the position as a middle manager for those without schoolwork. To put these results together, professional self-concept and job stress were factors affecting job satisfaction for dental hygienists with and without schoolwork. It is necessary to focus on the formation of good dental organizational culture through positive institutional support as well as through systematic establishment of professional self-concept.

• Journal of Convergence for Information Technology
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• v.10 no.5
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• pp.206-215
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• 2020

This study sought to find out the need for NCS education, Education awareness, and class satisfaction among professors and learners of nail art classes based on NCS. From April 21, 2017, to May 31, 2017, the questionnaire of 70 professors and 290 learners using NCS education located in Seoul and Gyeonggi Province was finally analyzed using the SPSS WIN 20.0 program. Analysis result, Professionals have a sense of self-efficiency (r=.466, p<.01), and appropriateness (r=.474, p<.01) has been confirmed. The learners identified static (+) relationships in the necessity of education (r=.338, p<.01), recognition (r=.193, p<.01), and self-efficiency (r=.586, p<.01), and appropriateness (r=.609, p<.01). Through this study, it is believed that NCS education necessity, Education awareness, and class satisfaction of professors and learners can be utilized as basic data.

• Journal of Convergence for Information Technology
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• v.10 no.5
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• pp.92-100
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• 2020

The purpose of this study is to analyze the relationship between export weight, import weight, export amount, import amount, and trade balance of ICT industry. The data used were gathered from the Korea Customs Service trade statistics. The analysis period used annual data for 19 years from 2000 to 2018. The change rate analysis was shown in order of trade balance, export amount, import amount, import weight and export weight. The increase rate analysis showed that the trade balance was the highest at 919%.. In the correlation analysis, the trade balance and export amount were 0.95, showing the highest correlation coefficient. As a result of the regression analysis, the export amount for the trade balance, the dependent variable, was Coefficient 2.37, which was positive(+). Each variable is changing independently of one another. Since 2000, the trade balance of the Korean ICT industry has led 84% of Korea's total trade balance. In the future, Korea's ICT industry should be further developed for Korea's economic development, and exports should be further increased to increase the trade balance. In the next paper, we will try to find a field that can be specifically developed by subdividing the ICT industry.

• Journal of Convergence for Information Technology
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• v.10 no.6
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• pp.200-208
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• 2020

The purpose of this study was to investigate and compare health, medical and welfare service providers' and local residents' perception on community care. The participants were 68 service providers and 95 local residents. The data were analyzed using independent t-test and chi-square test. The results showed that the degree of agreement of service providers on the need for policy, and visiting services were higher. Service providers' ability to link local residents with a need for care to community resources was higher, but in the activation of self-help group in community, local residents agreed more. In add budget of policy to health insurance, local residents agreed less. In perception on priority for community care policy, high priorities were preparation of financial resources and care culture. To effectively operate community care policy, it is necessary to establish a care culture through active exchanges for reducing differences in policy and opinions of recipients.