Seoung-Hey Paik

K‐8th grade Korean students' conceptions of ‘changes of state’ and ‘conditions for changes of state’

This study investigates the various conceptions held by K‐8th Korean grade students regarding the ‘changes of state’ and the ‘conditions for changes of state’. The study used a sample of five kindergarteners, five secondgrade students, five fourth‐grade students, five sixth‐grade students, and five eighth‐grade students. The 25 students attend schools in a rural district of South Korea. Some activities that involved a change in the state of water, including condensation, solidification, and melting, were chosen from K‐8th grade science textbooks and attempted by the students. Subsequently, we conducted interviews with the students. While most kindergarteners and second‐grade students were able to perceive the phenomena involving changes of state, they were unable to express conceptions related to the changes of state and the conditions under which the state the changes. The upper‐grade students, on the other hand, had some conception of the invisible gas state. Most of these students held conceptions about the boiling waters change of state from liquid to gas, but few of them held conceptions about the changes of state involving condensation. Most students understood heat and temperature as conditions of the changes of state, but only applied the heat concept to situations involving rising temperatures. In situations involving cooling, students applied the temperature concept. The younger students understood the concept of heat without understanding the concept of temperature.

IRIDIUM COMPLEXES WITH 3-METHYL-2,4-PENTANEDIONE LIGAND FOR ORGANIC ELECTROLUMINESCENT DEVICE

Phosphorescent materials, IR-FPPA1, IR-PPA1 and IR-TPA1 as emission dopants for electroluminescent (EL) devices were synthesized. Three types of devices such as ITO/ NPD/IR-FPPA1 (6%), IR-PPA1 (6%) and IR-TPA1 (6%) in CBP/BCP/Alq/LiF/Al were fabricated. IR-FPPA1, IR-PPA1 and IR-TPA1 exhibited 540 Cd/m2, 6600 Cd/m2 and 590 Cd/m2 with their external quantum efficiency of 1.2%, 8.9% and 3.0% in current densities of 20 mA/cm2, respectively. EL spectra of the IR-FPPA1, IR-PPA1, and IR-TPA1 devices had the band maxima at 490 nm, 535 nm and 615 nm, respectively.

Novel Green Phosphorescent Materials with Various Substituted Acetylacetonate Ligands for Organic Electroluminescent Device

Novel green phosphorescent materials, IR-PPA1, IR-PPA2 and IR-PPA3 were synthesized as emission dopants for electroluminescent(EL)devices. Four kinds of devices were fabricated and the structures of devices were ITO/NPD/IR-PPA1(6%), IR-PPA2(6%), IR-PPA3(6%)or IR-PPY(6%)in CBP/BCP/Alq/LiF/Al, where IR-PPY was used as a reference material for comparison. Novel phosphorescent materials, IR-PPA1, IR-PPA2 and IR-PPA3 represented the luminances of 3930 cd/m2, 3220 cd/m2and 2620 cd/m2, and their external quantum efficiencies, about 9.4%, 7.8%and 6.4%in 11 mA/cm2of current density in the EL devices, respectively. The maximum of EL spectra of novel emission dopants were detected at 532 nm in the IR-PPA1 device, and 525 nm in the IR-PPA2 device and 530 nm in the IR-PPA3 device.

Changes in Collaborative Discussion and Engagement with “Smart Technology” in Science Classroom

Smart mobile devices (mostly smartphones and tablets—mobile devices with higher computing power and Internet access) are now a familiar part of the everyday lives of most students and teachers in South Korea. 49.2 % of elementary, 85.4 % of middle, and 83.7 % of high school students in South Korea have a smartphone (Ministry of Education Science and Technology, 2013). They use their smartphones for text messages, social network services (SNS), Internet surfing, and entertainment (e.g., games). For educational purposes, students state that they use smartphones to search information using search engines or web 2.0 knowledge communities and to watch educational videos. Most of them indicate that they upload and share their own pictures and movies via a UCC service such as YouTube or a popular SNS service. Thus, today’s young students search, collect, and consume information and knowledge, but also produce and create knowledge and artifacts (Seol & Son, 2012).

Novel Red Phosphorescent Iridium- Phenylisoquinoline Complex for Organic Electroluminescent Device

Novel Red phosphorescent iridium complex with phenyl-isoquinoline ligands and 2-acetyl-cyclohexanone ligand (IR-PIQACH) was synthesized. The three types of EL devices, IR-PIQACH (5%)device, IR-PIQACH (10%)device and IR-BTPAC device were fabricated to measure electroluminescent (EL) characteristics. The layer-structures of the devices was following; IR-PIQACH (5%) device: ITO/ NPD/ IR-PIQACH (5%) in CBP/ Balq/ Alq/ LiF/ Al, IR-PIQACH (10%) device: ITO/ NPD/ IR-PIQACH (10%) in CBP/ Balq/ Alq/ LiF/ Al and IR-BTPAC (10%) device: ITO/ NPD/ IR-BTPAC (10%) in CBP/ Balq/ Alq/ LiF/ Al. Emission characteristics of the IR-PIQACH (5%) and IR-PIQACH (10%) devices were about 3830 cd/m2 and 3960 cd/m2 at 100 mA/cm2 at the same current density respectively. The EL spectra of the IR-PIQACH (5%) and IR-PIQACH (10%) devices were detected at about 635 nm and 637 nm with the maximum intensities at 11 mA/cm2.

Synthesis and Electroluminescent Properties of Novel Emissive Iridium Complex with Phenyl-isoquinoline Ligand

ABSTRACT Novel red phosphorescent iridium complex with two phenyl-isoquinoline ligands and one 2-acetyl-cyclopentanone ligand (IR-PIQCP) was designed and synthesized. The electroluminescent (EL) characteristics of IR-PIQCP were evaluated in the EL device. The three kinds of EL devices were fabricated by the vacuum deposition method, and the layer-structures of the devices were ITO/NPD/IR-PIQCP (5%), IR-PIQCP (10%) or IR-BTPAC (10%) in CBP/Balq/Alq/LiF/Al. Emission characteristics of the IR-PIQCP (5%) and IR-PIQCP (10%) devices were about 570 cd/m2 and 550 cd/m2 at 11 mA/cm2 at the same current density respectively. The EL spectra of the IR-PIQCP (5%) and IR-PIQCP (10%) devices were detected at about 627 nm and 629 nm as the maximum peak with red phosphorescence.