• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.12
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• pp.803-808
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• 2014

$Bi_{0.5+x}(Na_{0.78}K_{0.22})_{0.5-3x}TiO_3$ ceramics with an excess $Bi^{3+}$ and a deficiency of $Na^+$ and $K^+$ were synthesized by a conventional solid state reaction method. The structure and morphology of $Bi_{0.5+x}(Na_{0.78}K_{0.22})_{0.5-3x}TiO_3$ ceramics were characterized by X-ray diffraction and field emission scanning electron microscopy. The electric polarization and mechanical strain induced by external electric field, and the temperature dependence of dielectric constant were investigated. These results demonstrated that an ergodic relaxor phase can be induced by controls of the mole ratio of $Bi^{3+}$, $Na^+$ and $K^+$. A phase boundary between non-ergodic and ergodic relaxor phases can be observed at ambient temperature. The ergodic relaxor phase can be transferred to the ferroelectric phase by application of the electric field. The stability of the induced ferroelectric phases strongly depends on the mole ratio of $Bi^{3+}$, $Na^+$ and $K^+$. The maximum strain of 0.31% was observed in $Bi_{0.51}(Na_{0.78}K_{0.22})_{0.47}TiO_3$ ceramics sintered at $1,150^{\circ}C$ for 2 h.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.14-15
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• 2010

Recently there has been growing interest in topological insulators or the quantum spin Hall (QSH) phase, which are insulating materials with bulk band gaps but have metallic edge states that are formed topologically and robust against any non-magnetic impurity [1]. In a three-dimensional material, the two-dimensional surface states correspond to the edge states (topological metal) and their intriguing nature in terms of electronic and spin structures have been experimentally observed in bulk Bi1-xSbx single crystals [2,3,4]. However, if we want to know the transport properties of these topological metals, high purity samples as well as very low temperature will be needed because of the contribution from bulk states or impurity effects. In a recent report, it was also shown that an intriguing coupling between the surface and bulk states will occur [5]. A simple solution to this bothersome problem is to prepare a topological metal on an ultrathin film, in which the surface-to-bulk ratio is drastically increased. Therefore in the present study, we have investigated if there is a method to make an ultrathin Bi1-xSbx film on a semiconductor substrate. From reflection high-energy electron diffraction observation, it was found that single crystal Bi1-xSbx films (0${\sim}30\;{\AA}A$ can be prepared on Si(111)-$7{\times}7$. The transport properties of such films were characterized by in situ monolithic micro four-point probes [6]. The temperature dependence of the resistivity for the x=0.1 samples was insulating when the film thickness was $240\;{\AA}A$. However, it became metallic as the thickness was reduced down to $30\;{\AA}A$, indicating surface-state dominant electrical conduction. Figure 1 shows the Fermi surface of $40\;{\AA}A$ thick Bi0.92Sb0.08 (a) and Bi0.84Sb0.16 (b) films mapped by angle-resolved photoemission spectroscopy. The basic features of the electronic structure of these surface states were shown to be the same as those found on bulk surfaces, meaning that topological metals can be prepared at the surface of an ultrathin film. The details will be given in the presentation.

• Nuclear Engineering and Technology
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• v.1 no.2
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• pp.91-101
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• 1969

Resistivity changes of n-type float-zone silicon crystals with 6.4$\times$10$^{14}$ to 1.25$\times$10$^{17}$ phosphorus atoms/㎤ due to irradiation by (1) 1 MeV electrons, (2) two types of research reactors, and (3) $Co^{60}$ ${\gamma}$-ray sources were investigated. The results were analyzed on the basis of a simple exponential formula derived by Buehler. While the formula gave a fair fit in the low fluence range in most cases, the deviation was quite appreciable in the case of 1 MeV electron irradiation, and a linear change gave better fit in some cases. The large change in the carrier removal rate in electron-irradiated samples in the high fluence range was analyzed in detail in terms of the Fermi level cross-over of the defect levels. Based on the damage constants evaluated from the initial portion of data where the formula was applicable, the relative effectiveness of various radiation sources in causing the resistivity change in n-type silicon was compared. The TRIGA Mark II reactor neutrons, for example, were found to be about 40 times more effective than 1 MeV electrons. The dependence of the damage constant on the initial carrier concentration was also examined. The physical basis of the exponential law and the effect of the Fermi level cross-over of the defect levels on the resistivity change in the high fluence ranges are discussed.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.3
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• pp.219-226
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• 2021

Gastrodia elata has a very low pollination rate in natural state, and even in artificial cultivation, there are very few individuals that bloom due to the degeneration, so little studies have been conducted. This study confirmed that the potential as a cosmetic ingredient by evaluating the antioxidant activity through the evaluation of DPPH radical scavenging activity, anti-inflammatory activity through the inhibitory effect on nitric oxide production, and the moisturizing activity through the effect on promoting hyaluronic acid production by artificially flowering G. elata flower. It was also confirmed that the appearance rate and flowering rate of G. elata harvested in spring were high, and the content of gastrodin was 0.36%. The IC50 value of G. elata flower extract was 0.045% and it was confirmed that G. elata flower extract had higher radical scavenging activity than G. elata root extract. The NO production inhibitory activity against the flower extract showed a significant inhibitory effect from 1% to 83.2%. Hyaluronic acid production promotion efficacy was not confirmed in the G. elata root extract, but the production rate increased with concentration dependence in the flower extract, and it was the highest at 46.9% when 0.02% treatment was performed. Based on the above research results, it is judged that G. elata flower extract has high potential for use as an antioxidant, anti-inflammatory, and skin moisturizing cosmetic ingredient.

• The Journal of Korean Philosophical History
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• no.36
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• pp.259-291
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• 2013

This article is to study the purpose and significance of Chongyoulun of Peiwei, and it is composed of the two parts of philosophy and critical mind. The critical mind on Chongyoulun is as follows: first, it is mis-interpretative to define the main thought of Laozi as Xuwu. Next, the old philosophers did not criticize Xuwuism properly; as a result, they failed to stop spreading Xuwuism. Last, Guiwulun brought about the disorder of the way of life and the collapse of the public order. Based on this critical mind, Peiwei built up the following philosophy based on You as the fundamental principle of the existence and the movement of universal nature. First, Tao is the combined Wanyou, not abstract substance which is outside of Wanyou. Second, Wu is the state of being without You, and You only comes from You. Third, You can survive depending on external You because You is not the independent substance. Therefore, understanding the external You is the main factor of its existence. Fourth, Wanyou do not harm each other as they get together since Wanyous are interdependent. People are the being who can live through the mutual dependent relationships; hence, social system and morals (ethics) are key factors of the world in the oncological point of view. Wanyou had tried to rebuild the corrupted way of life and public order by recovering the justification of moral orders based on the mutual dependence of Wanyou which is the substance character.

• International Journal of Computer Science & Network Security
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• v.21 no.5
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• pp.183-191
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• 2021

The advanced development of the world's economies requires a detailed study of the impact of factors on the level of digitalization, to ensure economic growth and promote the use of information and communication technologies in the digital economy. Digitalization of the world's economies is ensured through the implementation of relevant regulations and policy decisions to implement public policy and strategy of the digital economy. The purpose of the study is to establish the pattern of the impact of factors on the level of digitalization of world economies by conducting a regression analysis to reflect the dependence of the impact of factors on the level of digitalization in 25 economies (by IMD digital competitiveness), to check the level of digitalization of the world's economies. It is necessary to analyze the ranking of countries in the world according to the DiGiX Index, IMD, and DESI Digital Competitiveness Rating. Research methods: information synthesis method; regression analysis; systematization, and generalization. Results. It was found that because of regression analysis, the value of the coefficient of determination indicates that the regression model by 78% explains the relationship between future readiness of countries to implement digital technologies and information and communication technologies, but there are still a small number of other factors not included in the regression model. It is determined that the greatest progress among EU member states for the period 2015-2020 according to the DESI index belongs to Ireland, the Netherlands, Malta, and Spain. It is established that Estonia, Spain, and Denmark are in the lead in the DESI rating, in terms of e-government implementation. The study found that the impact of factors on the level of digitalization of world economies contributes to solving current economic problems through further implementation of information and communication technologies and improving legislation in the digital economy, which will ensure the implementation of effective digital policy. It is established that ensuring the appropriate level of digitalization of the world's economies should solve the problems in the digital economy sector faced by governments and businesses, which requires the implementation of measures to regulate and ensure the continued operation of the digital economy.

• 한국노년학
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• v.41 no.3
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• pp.327-351
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• 2021

This study was motivated by the awareness that little attention has been paid to this issue both theoretically and empirically, despite the fact that financial abuse causes serious problems which are difficult for the elderly to recover from. This study intends to explore what the patterns of financial abuse targeting the elderly are, what causes and sustains these abuses, and what makes it difficult to counter such financial abuses. Data analysis was based on individual and group interviews of ten professionals expected to encounter the most financially abused elderly in social welfare institutions. The thematic analysis shows that financial abuse is often caused and maintained in a trusting relationship through care and protection. Because financial abuse was inflicted on the vulnerable elderly in a state of reinforced psychological dependence based on a long and trusting relationship, it appears that it has been made with tacit acknowledgement and consent. Despite those complex dynamics, it is noted that financial abuse can be judged as such only when the elderly claim to suffer from harm. Rather, intervention without victims' acknowledgement tends to be perceived as violating their right to self-determination. This reality naturally leads to the termination of the necessary interventions with the victims in an abusive situation. Based on these results, discussion focused on more realistic and diverse approaches to the issue of financial abuse of older adults.

• Journal of Intelligence and Information Systems
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• v.29 no.1
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• pp.107-119
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• 2023

The technology that recognizes a soldier's motion and movement status has recently attracted large attention as a combination of wearable technology and artificial intelligence, which is expected to upend the paradigm of troop management. The accuracy of state determination should be maintained at a high-end level to make sure of the expected vital functions both in a training situation; an evaluation and solution provision for each individual's motion, and in a combat situation; overall enhancement in managing troops. However, when input data is given as a timer series or sequence, existing feedforward networks would show overt limitations in maximizing classification performance. Since human behavior data (3-axis accelerations and 3-axis angular velocities) handled for military motion recognition requires the process of analyzing its time-dependent characteristics, this study proposes a high-performance data-driven classifier which utilizes the long-short term memory to identify the order dependence of acquired data, learning to classify eight representative military operations (Sitting, Standing, Walking, Running, Ascending, Descending, Low Crawl, and High Crawl). Since the accuracy is highly dependent on a network's learning conditions and variables, manual adjustment may neither be cost-effective nor guarantee optimal results during learning. Therefore, in this study, we optimized hyperparameters using Bayesian optimization for maximized generalization performance. As a result, the final architecture could reduce the error rate by 62.56% compared to the existing network with a similar number of learnable parameters, with the final accuracy of 98.39% for various military operations.

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.620-626
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• 2015

$Ho^{3+}$ doped $SrAl_2O_4$ upconversion phosphor powders were synthesized by spray pyrolysis, and the crystallographic properties and luminescence characteristics were examined by varying activator concentrations and heattreatment temperatures. The effect of organic additives on the crystal structure and luminescent properties was also investigated. $SrAl_2O_4:Ho^{3+}$ powders showed intensive green emission due to the $^5F_4/^5S_2{\rightarrow}^5I_8$ transition of $Ho^{3+}$. The optimal $Ho^{3+}$ concentration in order to achieve the highest luminescence was 0.1%. Over this concentration, emission intensities were largely diminished via a concentration quenching due to dipole-dipole interaction between activator ions. According to the dependence of emission intensity on the pumping power of a laser diode, it was clear that the upconversion of $SrAl_2O_4:Ho^{3+}$ occurred via the ground state absorption-excited state absorption processes involving two near-IR photons. Synthesized powders were monoclinic as a major phase, having some hexagonal phase. The increase of heat-treatment temperatures from $1000^{\circ}C$ to $1350^{\circ}C$ led to crystallinity enhancement of monoclinic phase, reducing hexagonal phase. The hexagonal phase, however, did not disappear even at $1350^{\circ}C$. When both citric acid (CA) and ethylene glycol (EG) were added to the spray solution, the resulting powders had pure monoclinic phase without forming hexagonal phase, and led to largely enhancement of crystallinity. Also, N,N-Dimethylformamide (DMF) addition to the spray solution containing both CA and EG made it possible to effectively reduce the surface area of $SrAl_2O_4:Ho^{3+}$ powders. Consequently, the $SrAl_2O_4:Ho^{3+}$ powders prepared by using the spray solution containing CA/EG/DMF mixture as the organic additives showed about 168% improved luminescence compared to the phosphor prepared without organic additives. It was concluded that both the increased crystallinity of high-purity monoclinic phase and the decrease of surface area were attributed to the large enhancement of upconversion luminescence.

• Journal of Korean Academy of Nursing
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• v.23 no.1
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• pp.118-129
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• 1993

In order to approach the nursing care of clients who are using oriental medicine and to understand the perception of the client who uses oriental medicine practices and the need to develop a model of nursing related to oriental medicine it is important to examine the major nursing concepts as they are found in oriental medicine and as they are differently defined according to the basic thought, theory and philosophical perspectives between East and West. Oriental medicine developed based on Sung Confucianism the teachings of Chut-zu, especially Tai-Chi-Tu Shuo and energy thought which are similar to traditional Korean Sasang Constitutional medicine. The basic theory on which oriental medicine is build is the theory of the five elements of Yin / Eum-Yang Theory(cosmic dual forces) and Meridian Theory. The most important attribute of Yin Yang is the concept of duality, confrontation and dependence, within Yin Yang but which do not exist separately. That is, the universe is a vast, indivisible entity within which all things exist in harmonious interdependence and balance. Harmony is achieved only when the two primorial forces, Yin and Yang, are brought into perfect balance. Each is contained within the other and there is a continuing interchange between the two. This also applies to the human body including human health which is defined as balanced harmony. The most universal connection of Yin and Yang is found in the universe where the five elements of life, fire, water, earth, wood and metal can be explained as having either Yin or Yang and therefore being in a state of connectedness but systematically circulating between the two, that is essentalilly one (the control of the unified ) or as coexistant poles of individual wholes (the pluralism of Yin Yang Theory) so that it is all unified(balanced) in the Great Absoulte. Human beings also maintain a balance of Yin and Yang in the five elements and this relationship is very important in approaching ·oriental medicine, The meridians are the channels in the body through which the life force flow throughout the body. In oriental medicine the meridians are seen as the railroad, the acupuncture points on the meridians as the stations and energy as the train. In the normal healthy organism, all are maintained in balance and in a contiuous circulation of energy. illness is the result of the energy flow becoming disarranged. Although practitioners of oriental medicine approach the client differently than do practitioners of Western medicine and their method of examining the patient is different, the basic objectives of the examination are the same for practitioners of both types of medicine. Therefore if each could be used to supplement the defiencies in the other and achieve a harmonious cooperation between the two, a higher level of care which is culturally appropriate to korean culture could be achieved. The traditional korean concept of health is a naturalistic view which emphasizes being in harmony with nature. Any manifestation of disease is considered a sign that the body is in a state of disequilibrium and is thus no longer in harmony with the universe. The wholistic view of the world held by practitioners of oriental medicine can be used by nursing in the development of a world view of nursing in which the human being is seen within the macrocosm as part of the natural phenomenon of the universe and but also as a microcosm of the universe, a universe which is a vast and indivisible entity within which all things exist in harmonious interdependence and balance. Interaction between human beings and their environment and the relationship of this interaction to health are concepts that are also found in nursing. Nursing views human brings, not as an accumulation of separate cells and organs but, as unified wholes interacted in very close relationship nth their environment. Nursing also maintains a view of human beings in which emphasis is placed on the role of the mind in explaining the concepts of harmony and balance in health. Although there are differences between oriental medicine and nursing in approaches to clients, the basic point of view and philosophy have many fundamental similarites. An understanding of the basic thought and philosophy of oriental medicine if applied to nursing, would allow for the development, not only of nursing related to oriental medicine, but of a nursing theory appropriate to the korean context.