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유치원, 초등, 중등 학생들의 고체, 액체, 기체의 압력개념 유형분석
김효남,조부경,백성혜 한국교원대학교 과학교육연구소 2003 청람과학교육연구논총 Vol.13 No.1
유치원에서 고등학생들 까지의 고체, 액체, 기체의 압력에 대한 개념 유형이 분석되었다. 28명의 학생들이 압력에 대한 활동을 하였고, 활동 전후에 압력에 대하여 면담하였다. 면담 내용이 비디오로 녹화되었고 전사되었다. 면담 내용은 지각적, 비과학적, 준과학적, 과학적 유형으로 나누어 보았다. 학생들이 학년이 올라갈수록 압력에 대한 과학적 유형의 응답이 많았는데, 이는 학생들의 인지수준의 발달과 학습의 결과로 보인다. 고체의 압력 크기는 대체로 초등학교 6학년에서, 고체의압력 방향에 대하여는 중학교 2학년에서 형성된 것으로 분석되었다. 액체의 압력 크기 개념은 고등학교 2학년에서, 액체의 압력 방향 개념은 초등학교 6학년에서 대체로 형성된 것으로 나타났다. 기체의 압력 크기와 기체의 압력 방향 개념은 고등학교 2학년에서 형성된 것으로 나타났다. 물질의 압력 개념은 대기압, 수압, 건물과 다리의 압력 등의 자연현상 이나 인공물에 나타나는 기본 개념이다. 이러한 압력 개념은 유치원에서 부터 고등학교 까지 체계적으로 나타나는 기본 개념이다.이러한 압력 개념은 유치원에서 부터 고등학교 까지 체계적으로 다루어져야 할 개념이다. 고체의 압력 크기와 방향, 액체의 압력 방향 개념은 초등학교 6학년에서 그리고 액체의 압력 크기와 기체의 압력크기와 방향 개념은 중학교 3학년에서 다루는 것이 학생들이 인지발달과 현재의 과학과 수학 교육과정을 고려할 때에 바람직하다고 본다. The K-12 students' conceptual patterns of the pressure of solid, liquid and gas are analyzed. Twenty eight students are interviewed after doing six activities about pressure. The interviews are video recorded and transcribed. The transcription is analyzed to find conceptual patterns about pressure. Students showed sensual, non-scientific, partial-scientific, and scientific patterns about pressure. The result showed that students understand pressure more scientifically according to increasing grades. The magnitude of pressure of solid is understood by the 6th grade; the direction of pressure of solid, by the 8th graders. The magnitude of pressure of liquid is understood by the 11th graders; the direction of pressure of liquid, by the 6th graders. The magnitude and the direction of pressure of gas is understood by the 11th graders. The pressure concept of matter is a basic concept about matter and natural phenomena such as atmosphere, water pressure, gas pressure and solid pressure in the buildings or bridges. The pressure concept should be taught in the K-12 science. It will be recomended that the pressure concept of solid is taught in the 6th grade, of liquid and gas, in the 9th grade.
Inkjet Printing of Polymeric Resistance Humidity Sensor Using UV-Curable Electrolyte Inks
Cho, Nam-Bu,Lim, Tai-Ho,Jeon, Young-Min,Gong, Myoung-Seon The Polymer Society of Korea 2008 Macromolecular Research Vol.16 No.2
UV-curable electrolytes inks were prepared by dissolving [2-[(methacryloyloxy)ethyl]dimethyl]propylaminium bromide (MEPAB), 1,5-[bis(2-methacryloxyethyl)dimethyl ammono]penthane dibromide (MDAPD), hexafunctional reactive oligomer (SP1013), trimethylolpropane triacrylate (TMPTA) and a photoinitiator in methanol/2-methoxyethanol. The compositions of the electrolyte inks were MEPAB/MDAPD/SP1013/TMPTA=6/24/17.2/12.8, 15/15/17.2/12.8 and 24/6/17.2/12.8. Humid-membranes were deposited on a gold electrode/alumina electrode using an ink-jet printer equipped with a UV lamp followed by immediate UV curing. The humidity-sensing characteristics including hysteresis, frequency and temperature dependence, response time and water durability were estimated.
Conduction mechanism change with transport oxide layer thickness in oxide hetero-interface diode
Nam, Bu-il,Park, Jong Seo,Lim, Keon-Hee,Ahn, Yong-keon,Lee, Jinwon,Park, Jun-woo,Cho, Nam-Kwang,Lee, Donggun,Lee, Han-Bo-Ram,Kim, Youn Sang American Institute of Physics 2017 APPLIED PHYSICS LETTERS Vol.111 No.5
Nam, Hyo-Jin,Kim, Young-Sik,Cho, Seong-Moon,Lee, Caroline-Sunyong,Bu, Jong-Uk,Hong, Jae-Wan The Institute of Electronics and Information Engin 2002 Journal of semiconductor technology and science Vol.2 No.4
Two kinds of PZT cantilevers integrated with a piezoresistor have been newly designed, fabricated, and characterized for high speed AFM. In first cantilever, a piezoresistor is used to sense atomic force acting on tip, while in second cantilever, a piezoresistor is integrated to calibrate hysteresis and creep phenomena of the PZT cantilever. The fabricated PZT cantilevers provide high tip displacement of $0.55\mu\textrm{m}/V$ and high resonant frequency of 73 KHz. A new cantilever structure has been designed to prevent electrical coupling between sensor and PZT actuator and the proposed cantilever shows 5 times lower coupling voltage than that of the previous cantilever. The fabricated PZT cantilever shows a crisp scanned image at 1mm/sec, while the conventional piezo-tube scanner shows blurred image even at $180\mu\textrm{m}/sec$. The non-linear properties of the PZT actuator are also well calibrated using the piezoresistive sensor for calibration.
Nam Hyo-Jin,Kim Young-Sik,Lee Caroline Sunyong,Jin Won-Hyeog,Jang Seong-Soo,Cho Il-Joo,Bu Jong-Uk The Society of Information Storage Systems 2005 정보저장시스템학회논문집 Vol.1 No.1
In this paper, a new silicon nitride cantilever integrated with silicon heater and piezoelectric sensor has been firstly developed to improve the uniformity of the initial bending and the mechanical stability of the cantilever array for thermo-piezoelectric SPM(scanning probe microscopy) -based data storages. This nitride cantilever shows thickness uniformity less than $2\%$. Data bits of 40 nm in diameter were recorded on PMMA film. The sensitivity of the piezoelectric sensor was 0.615 fC/nm after poling the PZT layer. For high speed operation, 128${\times}$128 probe array was developed.
Nam, Hyo-Jin,Jang, Seong-Soo,Kim, Young-Sik,Lee, Caroline-Sunyong,Jin, Won-Hyeog,Cho, Il-Joo,Bu, Jong-Uk The Institute of Electronics and Information Engin 2005 Journal of semiconductor technology and science Vol.5 No.1
Silicon nitride cantilevers integrated with silicon heaters and piezoelectric sensors were developed for the scanning probe microscope (SPM) based data storage application. These nitride cantilevers are expected to have better mechanical stability and uniformity of initial bending than the previously developed silicon cantilevers. Data bits of 40 nm in diameter were recorded on PMMA film and the sensitivity of the piezoelectric sensor was 0.615 fC/nm, meaning that indentations less than 20 nm in depth can be detected. For high speed operation, $128{\times}128$ cantilever array was developed.
Thermo-Piezoelectric Read/Write Mechanisms for Probe-Based Data Storage
Nam, Hyo-Jin,Kim, Young-Sik,Lee, Sun-Yong,Jin, Won-Hyeog,Jang, Seong-Soo,Cho, Il-Joo,Bu, Jong-Uk The Society of Information Storage Systems 2007 정보저장시스템학회논문집 Vol.3 No.1
In this paper, a thermo-piezoelectric mechanism with integrated heaters and piezoelectric sensors has been studied for low power probe-based data storage. Silicon nitride cantilever integrated with silicon heater and piezoelectric sensor has been developed to improve the uniformity of cantilevers. Data bits of 40 nm in diameter were recorded on PMMA film. The sensitivity of the piezoelectric sensor was 0.615 fC/nm after poling the PZT layer. And, the $34\times34$ probe array integrated with CMOS circuits has been successfully developed by simple one-step bonding process. The process can simplify the process step and reduce tip wear using silicon nitride tip.
Synergistic interaction of perovskite oxides and N-doped graphene in versatile electrocatalyst
Bu, Yunfei,Jang, Haeseong,Gwon, Ohhun,Kim, Su Hwan,Joo, Se Hun,Nam, Gyutae,Kim, Seona,Qin, Yong,Zhong, Qin,Kwak, Sang Kyu,Cho, Jaephil,Kim, Guntae The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.5
<P>Multifunctional electrocatalysts with high catalytic activity and durability are needed for environmentally clean energy technologies such as water-splitting devices and metal-air batteries. Herein, we investigate a new catalyst, P-3G, consisting of a cation-ordered perovskite (PrBa0.5Sr0.5)0.95Co1.5Fe0.5O5+δ (PBSCF) and 3D porous N-doped graphene (3DNG). This new type of composite electrocatalyst simultaneously exhibited outstanding multifunctional catalytic activities and excellent stabilities for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). A possible mechanism for the synergistic effects between perovskite oxides and 3DNG on ORR, OER and HER was firstly proposed by DFT calculations. The electrocatalytic activity of P-3G appeared to have great potential for a rechargeable Zn-air battery system. The operating voltage differences between the charge and discharge (Δ<I>η</I>) of P-3G and Pt/C-IrO2 after 110 cycles were 0.63 V and 0.87 V, respectively, indicating the substantial durability of P-3G. Moreover, a water-splitting device using P-3G efficiently produced H2 and O2 gases at rates of 0.859 μL s<SUP>−1</SUP> and 0.417 μL s<SUP>−1</SUP>, respectively. This study highlights extended applications of coupled perovskite oxides/carbon materials as versatile electrocatalysts for ORR, OER, and HER and unveils the cause of synergistic interactions between oxide and carbon by DFT calculation.</P>
Bu, Yunfei,Gwon, Ohhun,Nam, Gyutae,Jang, Haeseong,Kim, Seona,Zhong, Qin,Cho, Jaephil,Kim, Guntae American Chemical Society 2017 ACS NANO Vol.11 No.11
<P>Of the various catalysts that have been developed to date for high performance and low cost, perovskite oxides have attracted attention due to their inherent catalytic activity as well as structural flexibility. In particular, high amounts of Pr substitution of the cation ordered perovskite oxide originating from the state-of-the-art Ba<SUB>0.5</SUB>Sr<SUB>0.5</SUB>Co<SUB>0.8</SUB>Fe<SUB>0.2</SUB>O<SUB>3−δ</SUB> (BSCF) electrode could be a good electrode or catalyst because of its high oxygen kinetics, electrical conductivity, oxygen capacity, and structural stability. However, even though it has many favorable intrinsic properties, the conventional high-temperature treatment for perovskite synthesis, such as solid-state reaction and combustion process, leads to the particle size increase which gives rise to the decrease in surface area and the mass activity. Therefore, we prepared mesoporous nanofibers of various cation-ordered PrBa<SUB>0.5</SUB>Sr<SUB>0.5</SUB>Co<SUB>2–<I>x</I></SUB>Fe<SUB><I>x</I></SUB>O<SUB>5+δ</SUB> (<I>x</I> = 0, 0.5, 1, 1.5, and 2) perovskites <I>via</I> electrospinning. The well-controlled B-site metal ratio and large surface area (∼20 m<SUP>2</SUP> g<SUP>–1</SUP>) of mesoporous nanofiber result in high performance of the oxygen reduction reaction and oxygen evolution reaction and stability in zinc-air battery.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2017/ancac3.2017.11.issue-11/acsnano.7b06595/production/images/medium/nn-2017-06595y_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn7b06595'>ACS Electronic Supporting Info</A></P>