• Communications of Mathematical Education
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• v.37 no.3
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• pp.419-442
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• 2023

This study investigated fifth graders' understanding of variables from a generalized arithmetic and a functional perspectives of early algebra. Specifically, regarding a generalized perspective, we included the property of 1, the commutative property of addition, the associative property of multiplication, and a problem context with indeterminate quantities. Regarding the functional perspective, we covered additive, multiplicative, squaring, and linear relationships. A total of 246 students from 11 schools participated in this study. The results showed that most students could find specific values for variables and understood that equations involving variables could be rewritten using different symbols. However, they struggled to generalize problem situations involving indeterminate quantities to equations with variables. They also tended to think that variables used in representing the property of 1 and the commutative property of addition could only be natural numbers, and about 25% of the students thought that variables were fixed to a single number. Based on these findings, this paper suggests implications for elementary school students' understanding and teaching of variables.

• Journal of the Korean Vacuum Society
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• v.21 no.6
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• pp.328-332
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• 2012

The work function of Ag (silver) is too low (~4.3 eV) to be used as an electrode of T-OLED (Top Emission Organic Light Emitting Diode). To solve this weakness, researches used plasma-, UV-, or thermal treatment on Ag films in order to increase the work function (~5.0 eV). So, most of studies have focused only on the work function of various treated Ag films, but studies focusing on nanomechanical properties were very important to investigate the efficiency and life time of T-OLED etc. In this paper, we focused on the mechanical properties of the Ag and $AgO_x$ film. The Ag was deposited on a glass substrate with the thickness of 150 nm by using rf-magnetron sputter with the power was fixed at 100 W and working pressure was 3 mTorr. The deposited Ag film was UV treated by UV lamp for several minutes (0~9 min). We measured the sheet resistance and mechanical property of the deposited film. From the experimental result, there were some differences of the sheet resistance and surface hardness of Ag thin film between short time (0~3 min) and long time UV treatment. These result presumed that the induced stress was taken place by the surface oxidation after UV treatment.

• Carbon letters
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• v.9 no.4
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• pp.283-288
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• 2008

The composites of temperature-sensitive hydrogel and activated carbons were prepared in order to improve both the mechanical strength of hydrogel matrix and the loading capacity of drug in a hydrogel drug delivery system. The swelling of composite hydrogel was varied depending on the temperature. Both the swelling and the release behavior of the composite hydrogel were varied depending on the kind of activated carbon. The release behavior showed the high efficiency which is important for practical applications.

• Journal of Korea Game Society
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• v.16 no.5
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• pp.159-168
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• 2016

$Pok{\acute{e}}mon$ Go is an augmented reality (AR) game developed jointly by Niantic and Nintendo. It's a new type of augmented reality role-playing game (RPG) where AR elements like location information, visual recognition technology and GPS navigation technology are integrated with the intellectual property of the popular $Pok{\acute{e}}mon$ anime. The global success of $Pok{\acute{e}}mon$ Go can be attributed to the innovative incorporation of AR technologies into the game but also to the utilization of the Pokemon story which had been developed for 20 years. In summary, Pokemon Go is the fruitful result of a successful storytelling that combines the humanistic imagination of a popular, cultural archetype and the engineering imagination of AR game technologies.

• 한국정보컨버전스학회:학술대회논문집
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• 2008.06a
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• pp.205-208
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• 2008

Contents application from contents development of web technical base and with the operation different environment information of the educational resources integration the importance and necessity of the management central chain e-Learning system will be able to operate are raising its head with base. Is the actual condition which develops the development process where but, the education application currently is not standardized in base. Approaches with an educational domain from the present paper consequently, and defines MDA(Model Driven Architecture) coats e-Learning System. Also uses a studying contents standard metadata and about the contents storage space analyzes and plans the core property which uses MDA automatic tools leads and under developing boil e-Learning System will be able to provide the contents which does in actual professor own necessity.

• Natural Product Sciences
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• v.4 no.2
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• pp.58-61
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• 1998

Eurycoma longifolia Jack was evaluated for aphrodisiac property on sexually naive male mice using the electrical copulation cage. Optimum condition was provided for this study and the male mice were treated with 500 mg/kg of either chloroform, methanol, water or n-butanol fractions from E. longifolia Jack. However, the mice in the yohimbine and control groups received 30 mg/kg and 3 ml/kg of yohimbine and normal saline respectively. The male mice were then conditioned to seek either an estrous female, sexually vigorous male or no mouse, a measurement of right, wrong or no choice respectively. Besides this, hesitation time which was the time spent before the sexually naive male mice crossed the electrical grid (maintained at 0.12 mA) was also determined. Results showed that E. longifolia Jack possesses aphrodisiac property on the sexually naive male mice as shown by the slow and transient reduction in hesitation time and also a similar manner in the increase in the % of sexually naive male mice scoring right choice throughout the investigation period. Hence, this further supports the folkuse of this plant as aphrodisiac.

• Progress in Superconductivity and Cryogenics
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• v.25 no.3
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• pp.34-37
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• 2023

The practical application of REBCO coated conductor (CC) tapes, vital for energy transmission (e.g., cable application) and high-field magnets (e.g., coil application), necessitates efficient and simple quality assessment procedures. This study introduces a systematic approach to assess the electromechanical properties of REBCO CC tapes under 77 K and self-field conditions. The approach involves customized tensile and bending tests that clarify the critical current (I_c) response of the CC tapes under mechanical loads induced by tension and bending. This study measures the retained Ic values of commercially available GdBCO CC tapes under 250 MPa tensile stress and 40 mm bending diameter. Through experimentation, the study demonstrates the resilience of these tapes and their suitability for applications. By presenting a simplified stress-based analysis and a bending test of the tapes, the study contributes to effective quality assessment methods for the development of practical superconducting products.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.607-608
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• 2008

• Honam Mathematical Journal
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• v.36 no.1
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• pp.157-165
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• 2014

In this paper, we obtain some common fixed point theorems of single and multivalued maps under hybrid contractive conditions satisfying weakly commuting in IFMS. Our results extend previous ones in IFMS.

• Korean Journal of Mathematics
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• v.12 no.1
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• pp.55-65
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• 2004

Let $h_e(y)$, $h_o(y)$ denote the limits of the sequences {$^{2n}x$}, {$^{2n+1}x$}, respectively. From these two functions, we obtain a function $y=p(x)$ as an inverse function of them. Several differential properties of $y=p(x)$ are induced.