• Journal of the Korean Chemical Society
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• v.43 no.6
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• pp.636-643
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• 1999

Green-emission intensity of a $Zn_{2-x}Mn_xSiO_4$ phosphor, which is a potential candidate as a green component in PDP device, significantly increases provided that the compound is additionally heat treated at 900$^{\circ}C$ after solid state reaction at 1300$^{\circ}C$. In order to verify origin of such an intensity enhancement after the additional heat treatment in association with the electronic and local structural change at around Mn ions, the Mn K-edge X-ray absorption spectra were recorded. From the analyses of the preedge peak corresponding to $1s{\rightarrow}3d$ bound state transition and XANES spectrum, it is known that most Mn ions are in +2 oxidation state and substitute Zn ion site regardless of the thermal treatment. In addition, EXAFS analyses revealed that Mn ions formed $MnO_4$ tetrahedra with the Mn-O bond length shortened by 0.01${\AA}$ and with reduced Debye-Waller factor in the thermally treated sample.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.1
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• pp.61-70
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• 2016

This paper describes a new PMU(parametric measurement unit) design technique for automatic test equipment(ATE). Only one DDA(differential difference amplifier) is used to force the test signals to DUT(device under test), while conventional design uses two or more amplifiers to force test signals. Since the proposed technique does not need extra amplifiers in feedback path, the proposed PMU inherently guarantees stable operation. Moreover, to measure the response signals from DUT, proposed technique also adopted only one DDA amplifier as an IA(instrument amplifier), while conventional IA uses 3 amplifiers and several resistors. The DDA adopted two rail-to-rail differential input stages to handle full-range differential signals. Gain enhancement technique is used in folded-cascode type DDA to get open loop gain of 100 dB. Proposed PMU design enables accurate and stable operation with smaller hardware and lower power consumption. This PMU is implemented with 0.18 um CMOS process and supply voltage is 1.8 V. Input ranges for each force mode are 0.25~1.55 V at voltage force and 0.9~0.935 V at current force mode.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.9
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• pp.613-622
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• 2012

A chrome absorbent that is useful in rapid magnetic recovery and recycling was developed though a synthesis of Multi-Terminalized Magnetic-core Dendrimer (MTMD). Divergence through coprecipitation and rotation growth was used for synthesis. The dendrimer was multi-terminilized through methyl propionate and glutaric acid. The property analysis of the synthesized sample was performed through XRD, FT-IR, TEM, EDS, TGA and zeta potential analyzer. A magnetic-core of MTMD had a magnetite crystal and the size of 4th generation dendrimer was identified to be from 15 nm to 20 nm. Through the analysis of the TGA, the rate of the dendrimer branch for the first generation dendrimer was about 7% and 3% of diminished weight occurred as the generation grows. Also, the potential of the dendrimer when multi-terminalized, had variation from 25.26 mV to -6.53 mV. As a result of MTMD adsorption experiment, it absorbed more than 80% within 5 minutes and indicated absorptivity of 6.308 mg/g. When it was compared with COOH Dendrimer (COOH-D) after magnetic recovery, the recovery time was rapidly reduced by more than half and it could recover 100% within 30 minutes. In case of the regeneration experiment that used chrome, it was identified to maintain the same adsorptivity for four runs.

• Proceedings of the Korean Society of Toxicology Conference
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• 2000.11a
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• pp.45-67
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• 2000

2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) is a mutagenic and carcinogenic heterocyclic amino found in cooked meat. The in vivo mutagenicity and hepatocarcinogenicity of MeIQx were examined in mice harboring the lacZ mutation reporter gene ($Muta^{TM}$ Mice) and bitransgenic mice over-expressing the c-myc oncogene. C57B1/$\lambda$lacZ and bitransgenic c-myc (albumin promoter)/$\lambda$lacZ mice were bred and weaned onto an AIN-76 based diet containing $0.06\%$ (w/w) MeIQx or onto control diet. After 30 weeks on diet, only male bitransgenic mice on MeIQx developed hepatocellular carcinoma ($100\%$ incidence) indicating that there was synergism between c-myc over-expression and MeIQx. By 40 weeks, hepatic tumor incidence was $100\%$ ($17\%$) and $44\%$ ($0\%$) in male c-myc/$\lambda$lacZ and C57B1/$\lambda$lacZ mice given MeIQx (or control) diet, respectively, indicating that either MeIQx or c-myc over-expression alone eventually induced hepatic tumors. At either time point, mutant frequency in the lacZ gene was at least 40-fold higher in MeIQx-treated mice than in control mice of either strain. These findings suggest that MeIQx-induced hepatocarcinogenesis is associated with MeIQx-induced mutations. Elevated mutant frequency in MeIQx-treated mice also occurred concomitant with the formation of MeIQx-guanine adducts as detected by the $^{32}P$-postlabeling assay. Irrespective of strain or diet, sequence analysis of the lacZ mutants from male mouse liver showed that the principal sequence alteration was a single guanine-base substitution. Adenine mutations, however, were detected only in animals on control diet. MeIQx-fed mice harboring the c-myc oncogene showed a l.4-2.6-fold higher mutant frequency in the lacZ gene than mice not carrying the transgene. Although there was a trend toward higher adduct levels in c-myc mice, MeIQx-DNA adduct levels were not significantly different between c-myc/$\lambda$lacZ and C57B1/$\lambda$lacZ mice after 30 weeks on diet. Thus, it appeared that factors in addition to MeIQx-DNA adduct levels, such as the enhance rate of proliferation associated with c-myc over-expression, may have accounted for a higher mutant frequency in c-myc mice. In the control diet groups, the lacZ mutant frequency was significantly higher in c-myc/$\lambda$lacZ mice than in 057B1/$\lambda$1acZ mice. The findings are consistent with the notion that c-myc over-expression is associated with an increase in mutagenesis. The mechanism for the synergistic effects of c-myc over-expression on MeIQx hepatocarcinogenicity appears to involve an enhancement of MeIQx-induced mutations.

• Korean Journal of Construction Engineering and Management
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• v.24 no.6
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• pp.63-65
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• 2023

BIM and AR technologies have been assessed as a means of enhancing productivity within the construction industry, through the provision of effortless access to critical data on site, achieved via the projection of 3D models and associated information onto actual structures. However, most of the previous researches for applying AR technology in construction quality management has been performed for construction projects in general, resulting in only overall on-site management solutions. Also, a few previous researches for the application of AR in the quality management of specific elements like reinforcements focused only on simple projection, so conducting specific quality inspection was impossible. Hence, this study aimed to develop a practically applicable BIM-based AR quality management system targeted for reinforcements. For the development of this system, the reinforcement inspection items on the quality checklist used at railway construction sites were analyzed, and four types of AR functions that can effectively address these items were developed and installed. The validation result of the system for the actual railway bridge showed a degradation of projection stability. This problem was solved through model simplification and enhancement of the AR device's hardware performance, and then the normal operation of the system was validated. Subsequently, the final developed reinforcement quality inspection system was evaluated for practical applicability by on-site quality experts, and the efficiency of inspection would significantly increase when using the AR system compared to the current inspection method for reinforcements.

• The Journal of the Convergence on Culture Technology
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• v.10 no.2
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• pp.357-363
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• 2024

As AR display virtual technology enters public learning life extensively, the way in which reality and virtual connection are connected is also changing. The purpose of this paper is to study the expression between the 3D connection sensory information visualization experience and virtual reality enhancement through the visual direction sensory information visualization experience of the plane. It is analyzed by examining the basic setting method compared to the current application of AR display and flat visualization cases. The scope of this paper is to enable users to have a better experience through the relationship with sensory visualization, centering on eye tracking technology in the four categories of AR display connection design: gesture connection, eye tracking, voice connection, and sensor. Focusing on eye tracking technology through AR display interaction and current application and comparative analysis of flat visualization cases, the geometric consistency of visual figures, light and color consistency, combination of multi-sensory interaction methods, rational content display, and smart push presented sensory visualization in virtual reality more realistically and conveniently, providing a simple and convenient sensory visualization experience to the audience.

• Journal of Ginseng Research
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• v.39 no.3
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• pp.265-273
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• 2015

Background: Cancer has emerged as a major health problem globally as a consequence to the increased longevity of the population, changing the environment and life style. Chemoprevention is a new and promising strategy for reducing cancer burden. Recently, some natural products have been identified for their chemopreventive activity to reduce the cancer incidence. Ginseng is known for its potential to treat various ailments in human beings. The present study was designed to explore the anticancer and antioxidative potential of Panax ginseng against chemical-induced skin carcinogenesis in mammals. Methods: Skin tumors were induced in Swiss albino mice by a single topical application of 7,12-dimethylbenz(a)anthracene ($100{\mu}g/100{\mu}L$ acetone) and, 2 wks later, promoted by repeated applications of croton oil (thrice in a wk in 1% acetone) till the end of the experiment (i.e., 16 wk). Hydroalcoholic ginseng root extract at a dose of 25 mg/kg body weight/d was orally administered at the periinitiation, postinitiation, and peri-post-initiation stages. Results: Ginseng root extract treatment caused a significant reduction in tumor incidence, cumulative number of tumors, tumor yield, and tumor burden, as compared to the 7,12-dimethylbenz(a)anthracene-croton oil-treated control group. Further, biochemical assays revealed a significant enhancement in the levels of reduced glutathione, superoxide dismutase, catalase, vitamin C, and total proteins but a significant reduction in lipid peroxidation levels in both the liver and skin with ginseng root extract treatment, as compared to carcinogen-treated control group. Conclusion: These results suggest that P. ginseng has the potential to become a pivotal chemopreventive agent that can reduce cancer in mammals.

• The Korean Journal of Air & Space Law and Policy
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• v.6
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• pp.267-283
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• 1994

Application of space technology in the field of communication and remote sensing becomes increasingly important in human life. Advancement of communications means shinks the size of our globe and that of remote sensing techniques improves the quality of human well-being. It is a world trent for each country to make its best effort in advancing its capabilities in these fields sometimes independently and other times jointly with other nations. Korea being no exception to this world trend is planning various starategies in application and development of space technologies. However, unfortunately, Korea is a new commer in this field. Statellite Technology Research Center (SaTReC) of Korea Advanced Institute of Science and Technology (KAIST) initiated to aquire satellite technology by sending its graduates abroad in 1989. As a result KITSAT-1 was launched in 1992 and KITSAT- 2 was launched in 1993 and they became Korea's first two satellites in orbits. Academic program including On-the Job-Training for Korean students at the University of Surrey, UK, is also an innovative scheme of mixing education and practical know-how for successful technology transfer, which resulted in a small but very capable and effective satellite experts group in Korea for self-propelled research and development in space activities. In this context, space development strategy should be considered in terms of the following factors; (1). Participation in international space activities as an active member to utilize international organization and to contribute to the peaceful use of space, (2). Development of national defence structure for independent activities in space, (3). Enhancement of manpower utilization for space development and promotion of national pride and (4). Education of youngsters for the extension of intellectual activities into the limitless space. In order to make very costly space development project most efficient, governmental level space development organization directed by the head of nation should be established and should manage all space development programs making full use of its all available resources including the advantage of the university based R&D capability.

• Solar Energy
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• v.13 no.2_3
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• pp.91-106
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• 1993

The purpose of this study was to investigate the enhancement of heat transfer coefficient in double pipe fluidized bed heat exchangers. The inner tube used a smooth tube and a finned tube equipped with longitudinal fins. The heat transfer coefficients between the heated tube and fluidized bed of alumina beads were calculated as a function of fluidized velocity in various particle sizes($d_p$=0.41, 0.54, 0.65, 0.77mm) and static bed heights($H_o$=50, 100, 150, 200, 250mm). The coefficient for finned tube is higher than for smooth tube. And the maximum increasing rate is 7.8 times in smooth tube and 12.9 times in finned tube.

• Archives of design research
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• v.6 no.1
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• pp.11-22
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• 1993

The purpose of this study was to provide basic information for establishment of a desirable design promotion policy drive by research and analysis of recognition to design by consumers (including students) and designers and their level, merchandise evaluation evaluation and obstructing factors in revitalization of designs. To implement such purpose as referred to hereinabove, research was made by introduction of questionaires which were distributed to 500 persons of consumers group and 350 individuals of registered designers in Seoul, and for analysis of the data, density and percentage (%) were obtained by use of SAS Package and the dispersed analysis and correlationship were added for necessary parts. The result of study is summarized as follows; (l)The consumers remind the design as costume (21%) and molding (20%), and the designers remind it as creativity (27%) & molding (14%) respectively and the reminding of design by the two groups was indicated very simi lar. (p < 0.001) (2)As per the recogni tion of roles by the designers the research has highly indicated as contribution to improving living standards or development of economy & industry, and also indicated that it creates excessive consumption with sti$$\mu$ative manner. (3)The design reacts as an important parameter in selecting cri teria of merchandises and deciding factors for purchasing and also, in enhancement of competitive power of merchandise impact of design (2.36) was regarded very high. (4)The Korean-made home appliances in image is assessed as vulnerable than that of Japanese products, and the product designing level is also shown difference from advanced countries (1.36), but has indicated as somewhat better than those competitive nations (0.51) (5)The satisfaction to design policy of the Gov't is very low (1.69) and they recommended for new establishment of Policy undertaking department within the Gov't and indicated reasearch & development of design as the major issue. In regard to the above I'd like to emphasize the design industry $$\mu$t be dealt with the national level as a whole in order to promote thereof.