• 대한화학회지
• /
• 제55권2호
• /
• pp.189-198
• /
• 2011

두 가지 새로운 thiosemicarbazone으로, 예를 들면, 4[N-(4'-ethylbenzalidene)amino]antipyrine thiosemicarbazone(EBAAPTS) 및 4[N-(2',4'-dimethylbenzalidene)amino]antipyrine thiosemicarbazone(DMBAAPTS)를 합성하여 그 특성을 규명하였다. 이들 thiosemicarbazone(EBAAPTS 및 DMBAAPTS)의 코발트(II) 및 니켈(II)에 대한 착물화 특성을 조사하였다. EBAAPTS 및 DMBAAPTS와 코발트(II) 및 니켈(II) 염과의 반응을 뜨거운 에탄올 용액에서 수행한 결과, 일반적 조성으로 [$MX_2(L)H_2O$] (M=$Co^{2+}$ 또는 $Ni^{2+}$; X=$Cl^-$, $Br^-$, $NO_3^-$, $NCS^-$ 또는 $CH_3COO^-$; L=EBAAPTS 또는 DMBAAPTS)을 갖는 새로운 착물의 형성을 확인하였다. 새롭게 합성한 이들 착물에 대해 원소분석, 분자량, 몰전도도, 자기수자율, 적외선 및 자외선 분광학 등의 방법으로 특성을 규명하였다. 니트로벤젠 용액에서 이들 착물의 몰전도도를 측정한 결과, 비전해질 성질을 가짐을 알았다. 또한, 모든 착물은 높은-스핀 형태였다. 분광학적 연구로부터 [$MX_2(L)H_2O$] 형의 코발트(II) 및 니켈(II) 착물은 팔면체의 기하구조를 갖는 것으로 확인되었다. 이들 착물을 이용하여 항박테리아 및 항균 활성을 여러 종류의 병원균, 세균 및 박테리아에 대해 조사하여 생물학적 활성을 고찰하였다.

• EDISON SW 활용 경진대회 논문집
• /
• 제4회(2015년)
• /
• pp.392-395
• /
• 2015

Metal Mono Chalcogenides(MMC)는 각각의 III족 metal 원자당한개의 chalchogen 원자를 갖고 있는(MX, M=Ga and In, X=S, Se, and Te)층상구조 화합물이다. MMC가 주목받는 가장 큰 이유는 single tetralayer MMC(SL-MMC)라는 2차원 구조를 갖기 때문이다. 2차원 물질은 다양한 물리적 현상을 증명하기 용이하다는 특징을 갖는다. 이 논문에서 우리는 SL-MMC중 Ga-MMC에서 chalchogen 원자가 변화함에 따라 바뀌는 실험 lattice constant를 조사하여 band gap과 formation energy를 Density Function Theory(DFT)로 계산했다.

• 한국자기학회지
• /
• 제5권5호
• /
• pp.874-879
• /
• 1995

고 포화자속밀도를 갖는 Fe미세결정 박막의 자기특성 및 미세구조에 미치는 첨가원소의 영향을 조사하였다. Mo 첨가 박막의 경우, $Fe_{2}Mo$, $Fe_{4}N$, $Fe_{3-2}N$상의 생성으로 연자기 특성이 발현되지 않았다. Ta첨가 박막의 경우, 미세한 TaN, TaC 상이 석출하여 $\alpha$-Fe 결정립을 효과적으로 미세화 시켰으며 Fe 질화물의 생성도 억제되었다. 이에 따라 우수한 연자기 특성이 발현되었으며 FeTaN계 박막은 4000, FeTaC 박막은 2700의 높은 투자율을 나타내었다.

• Bulletin of the Korean Chemical Society
• /
• 제23권10호
• /
• pp.1463-1482
• /
• 2002

Partially doped Aurivillius phases SrBi2N$b_{2-x}M_xO_9$ (M=Cr and Mo) were successfully synthesized and characterized. The extent of the substitution was limited at ~20 mole % because of the size differences between $Nb^{5+}$ and $Cr^{6+}$, and between $Nb^{5+}$ and $Mo^{6+}$. When the amount of substitution exceeded ~20 mole%, the phases began to collapse and the second phases were made. The dielectric constants of substituted compounds were enlarged nevertheless Cr or Mo is substituted. The increment is bigger in the Mo substituted compound than in the Cr doped one although the Nb(Cr)$O_6$ octahedra could be more strongly distorted than the Nb(Mo)$O_6$ octahedra since the ionic size difference between $Nb^{5+}$ and of $Cr^{6+}$ is much bigger than that between $Nb^{5+}$ and $Mo^{6+}$. Consequently, the dielectric constant of the substituted Aurivillius phase $Bi_2$A_{n-1}B_{n-x}M_xO_{3n+1}$$ depends on the extent of distortion of the B$O_6$ octahedra and more strongly on the polarizability of the metal.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.375-375
• /
• 2014

Layered semiconductor materials can be a promising candidate for large-area thin film transistors (TFTs) due to their relatively high mobility, low-power switching, mechanically flexibility, optically transparency, and amenability to a low-cost, large-area growth technique like thermal chemical vapor deposition (CVD). Unlike 2D graphene, series of transition metal dichalcogenides (TMDCs), $MX_2$ (M=Ta, Mo, W, X=S, Se, Te), have a finite bandgap (1~2 eV), which makes them highly attractive for electronics switching devices. Recently, 2D $MoS_2$ materials can be expected as next generation high-mobility thin-film transistors for OLED and LCD backplane. In this paper, we investigate in detail the electrical characteristics of 2D layered $MoS_2$ local bottom-gated transistor with the same device structure of the conventional thin film transistor, and expect the feasibility of display application.

• Nutrition Research and Practice
• /
• 제10권5호
• /
• pp.555-562
• /
• 2016

BACKGROUND/OBJECTIVES: Childhood obesity has become a global epidemic. Development of effective and sustainable programs to promote healthy behaviors from a young age is important. This study developed and tested an intervention program designed to promote healthy eating and physical activity among young children in South Korea by adaptation of the US National Aeronautics and Space Administration (NASA) Mission X (MX) Program. SUBJECTS/METHODS: The intervention program consisted of 4 weeks of fitness and 2 weeks of nutrition education. A sample of 104 subjects completed pre- and post- surveys on the Children's Nutrition Acknowledgement Test (NAT). Parents were asked for their children's characteristics and two 24-hour dietary records, the Nutrition Quotient (NQ) at baseline and a 6-week follow-up. Child weight status was assessed using Korean body mass index (BMI) percentiles. RESULTS: At baseline, 16.4% (boy: 15.4%; girl: 19.2%) of subjects were overweight or obese (based on $BMI{\geq}85%tile$). Fat consumption significantly decreased in normal BMI children ($48.6{\pm}16.8g$ at baseline to $41.9{\pm}18.1g$ after intervention, P < 0.05); total NQ score significantly increased from 66.4 to 67.9 (P < 0.05); total NAT score significantly improved in normal BMI children (74.3 at baseline to 81.9 after the program), children being underweight (from 71.0 to 77.0), and overweight children (77.1 at baseline vs. 88.2 after intervention, P < 0.001). CONCLUSIONS: The 6-week South Korean NASA MX project is feasible and shows favorable changes in eating behaviors and nutritional knowledge among young children.

• 한국재료학회지
• /
• 제23권3호
• /
• pp.155-160
• /
• 2013

ZnO thin films co-doped with Mg and Ga (MxGyZzO, x + y + z = 1, x = 0.05, y = 0.02 and z = 0.93) were prepared on glass substrates by RF magnetron sputtering with different sputtering powers ranging from 100W to 200W at a substrate temperature of $350^{\circ}C$. The effects of the sputtering power on the structural, morphological, electrical, and optical properties of MGZO thin films were investigated. The X-ray diffraction patterns showed that all the MGZO thin films were grown as a hexagonal wurtzite phase with the preferred orientation on the c-axis without secondary phases such as MgO, $Ga_2O_3$, or $ZnGa_2O_4$. The intensity of the diffraction peak from the (0002) plane of the MGZO thin films was enhanced as the sputtering power increased. The (0002) peak positions of the MGZO thin films was shifted toward, a high diffraction angle as the sputtering power increased. Cross-sectional field emission scanning electron microscopy images of the MGZO thin films showed that all of these films had a columnar structure and their thickness increased with an increase in the sputtering power. MGZO thin film deposited at the sputtering power of 200W showed the best electrical characteristics in terms of the carrier concentration ($4.71{\times}10^{20}cm^{-3}$), charge carrier mobility ($10.2cm^2V^{-1}s^{-1}$) and a minimum resistivity ($1.3{\times}10^{-3}{\Omega}cm$). A UV-visible spectroscopy assessment showed that the MGZO thin films had high transmittance of more than 80 % in the visible region and that the absorption edges of MGZO thin films were very sharp and shifted toward the higher wavelength side, from 270 nm to 340 nm, with an increase in the sputtering power. The band-gap energy of MGZO thin films was widened from 3.74 eV to 3.92 eV with the change in the sputtering power.