• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.336-336
• /
• 2012

유기물/무기물 하이브리드 나노 복합체를 사용하여 제작한 비휘발성 유기 메모리 소자는 공정의 간편성과 휘어짐이 가능한 장점을 가지고 있어 많은 연구가 활발히 진행되고 있으나 대부분의 좋은 전기적 성능을 갖는 소자에 포함되는 나노 입자는 독성을 가지거나 가격이 비싸다는 단점을 갖고 있다. 인체진화적이며 가격이 저렴한 나노입자를 이용한 비휘발성 메모리 소자에 대한 전기적 성능의 안정성에 대한 연구는 미미한 상황이다. 이에 본 연구에서는 인체친화적 $CuInS_2(CIS)$-ZnS 코어-쉘 나노 입자가 분산되어 있는 poly (methylmethacrylate) (PMMA) 박막을 사용하여 비휘발성 메모리 소자를 제작하여 전기적 성능과 안정성에 대한 연구를 하였다. 인체친화적 CIS-ZnS 나노입자를 포함한 PMMA 용액을 Al 하부전극을 가진 p-Si (100) 기판 위에 스핀코팅 방법으로 균일하게 도포 하였다. 남아 있는 용매를 완전히 제거하기 위해 열을 가해 CIS-ZnS 나노입자가 분산되어 있는 PMMA 나노 복합체를 형성하였다. CIS-ZnS 나노입자를 포함한 PMMA 박막 위에 금속 마스크를 사용하여 Al 상부전극을 열 증착 방법으로 형성하여 비휘발성 메모리 소자를 완성하였다. 정전용량-전압 (C-V) 측정을 하여 평탄 전압 이동을 관찰하였고, CIS-ZnS 나노입자의 역할을 알아보기 위해 나노입자가 없는 PMMA 박막을 갖는 소자를 제작하여 동일한 조건에서 C-V 측정을 하였다. 소자의 안정성을 알아보기 위해 평탄 전압-유지 시간 (Vth-t) 측정을 수행하였다. Vth-t 측정은 CIS-ZnS 나노입자가 전하 포획 장소로 사용할 수 있는 것과 전기적 안정성을 갖고 있는 것을 확인하였다. C-V와 Vth-t 측정결과 및 에너지 대역도를 사용하여 CIS-ZnS 나노입자가 분산되어 있는 PMMA 박막을 포함한 나노 복합체를 사용하여 제작한 이용한 비휘발성 메모리 소자에서 전하수송 메커니즘을 설명하였다.

• Applied Biological Chemistry
• /
• v.38 no.5
• /
• pp.414-421
• /
• 1995

In order to establish informations important to the measurement of lipoxygenase (LOX) activity, providing conditions most favorable for its action and determining factors that inhibit activity, the influence of extraction buffer, substrate, pH, storage, temperature, NaCl, $CaCl_2$, other cations and antioxidants on LOX activity, and localization of LOX in cucumber tissues were carried out. The most favored substrate for LOX was linolenic acid followed by linoleic and arachidonic acids. LOX activity in both peel and mesocarp tissue extracts was maximum at pH 5.5 and relatively stable at $40^{\circ}C\;and\;50^{\circ}C$ temperature. The condition of 0.2 M NaCl with pH 5.0 was observed to provide optimum LOX stability. The enzyme activity was reduced by addition of cations, $Mn^{2+},\;Cu^{2+}\;or\; Al^{3+}$, except $Ca^{2+}$ which stimulated activity of LOX. Butylated hydroxy anisole (BHA) and propyl gallate decreased LOX activity with increasing concentration. Cucumber peel had higher activity than other tissues, locule or mesocarp, of cucumber.

• Advances in materials Research
• /
• v.5 no.1
• /
• pp.55-66
• /
• 2016

This paper describes a study on the effects of $Mg_2Si_{(p)}$ addition on the microstructure, porosity, and mechanical properties namely hardness and tensile properties of AA332 composite. Each composite respectively contains 5, 10, 15, and 20 wt% reinforcement particles developed by a stir-casting. The molten composite was stirred at 600 rpm and melted at $900^{\circ}C{\pm}5^{\circ}C$. The $Mg_2Si$ particles were wrapped in an aluminum foil to keep them from burning when melting. The findings revealed that the microstructure of $Mg_2Si_{(p)}/AA332$ consists of ${\alpha}$-Al, binary eutectic ($Al+Mg_2Si$), $Mg_2Si$ particles, and intermetallic compound. The intermetallic compound was identified as Fe-rich and Cu-rich, formed as polygonal or blocky, Chinese script, needle-like, and polyhendrons or "skeleton like". The porosity of $Mg_2Si_{(p)}/AA332$ composite increased from 8-10% and the density decreased from 9-12% from as-cast. Mechanical properties such as hardness increased for over 42% from as-cast and the highest UTS, elongation, and maximum Q.I were achieved in the sample of 10% $Mg_2Si$. The study concludes that combined with AA332, the amount of 10 wt% of$Mg_2Si$ is a suitable reinforcement quantity with the combination ofAA332.

• Journal of Korea Foundry Society
• /
• v.10 no.1
• /
• pp.31-42
• /
• 1990

The full mould casting process in one of the newly developed techniques which has many advantages. Unbonded sand mould has been prepared for the major mould and $CO^2$ gas mould has been used occasionally for comparison. Patterns were built up with expanded polystyrene and coated with three different materials. Silica, graphite and zircon were used for the coating layer. The effects on fluidity and temperature loss of molten metals were investigated. The molten metals were Al-5% Si alloy, Cu-30% Zn alloy and gray iron of approximately 4.0% of carbon equivalent. Experimental variables were runner section area, superheat, sprue height, coating materials, coating thickness and apparent density of EPS pattern. The effects of coating materials on fluidity and temperature loss of the molten metals during transient pouring are summarized as follows : As runner section area, superheat and sprue height increased, fluidity increased. Temperature loss decreased as runner section area and sprue height increased. However, reversed effects were observed in the case of superheat increment. The coating materials decreased the fluidity of each alloy in the order of silica, graphite and zircon. Zircon brought to the highest temperature loss among the coating materials used. The fluidity increased in the order gray iron, Cu-30% Zn and Al-5% Si alloy while temperature loss in the reverse order. Especially in case of reduced pressure process, the fluidity was increased apparently. Al-5% Si alloy showed the lowest temperature loss among the alloys. The increment of the apparent density of EPS pattern resulted in the fluidity decrease and temperature loss increase. The relation between fluidity and temperature loss of each alloy can be expressed by the following equation within the coating thickness limit of 0.5-1.5㎜. F^*={\frac{a}{T^*-b}}-c$ where, $F^*$ : fluidity in the Full mould, $T^*$ : temperature loss in the mould. a : parameter for full mould. b, c : constants.

• Journal of Korea Foundry Society
• /
• v.14 no.3
• /
• pp.240-247
• /
• 1994

TiC particulate reinforced magnesium matrix composites were fabricated by melt stirring method. The effect of alloying elements on TiC particulate dispersion into molten magnesium and mechanical properties were investigated. The incorporation time is defined as the time required for dispersion of solid particles into molten metal. The incorporation time of TiC particles into molten pure magnesium was remarkably shorter and the particulated dispersion was more uniform than that of pure aluminum which was reported previously. The incorporation time was, prolonged by the addition of Al, Bi, Ca, Ce, Pb, Sn or Zn. The tensile strength increased and elongation decreased by the addition of Cu or Sn into the matrices and composites. Although, the tensile strength of the matrices and composites increased by alloying with Ca or Ce, the maximum elongation was observed at a content of about 1% for the matrices. By alloying with Zn, the tensile strength increased for the matrices and composites, but the elongation of the matrices increased. The pure magnesium and its alloy matrix composites reinforced with 20vol% TiC have the tensile strength of about 400MPa. This value is compared with the tensile strength of SiC whisker reinforced magnesium matrix composites fabricated by liquid infiltration method at the same volume fraction. There fore, the melt strirring method which has the advantages of simple process is considered to be efficient in fabricating magnesium matrix composites.

• Journal of the Korean Magnetics Society
• /
• v.17 no.1
• /
• pp.22-25
• /
• 2007

In this research, magnetic properties of spin valve structures using IrMn layers as antiferromagnetic were studied depending on the thickness of the pinned layer. The spin valve structure was Si substrate/$SiO_2(2,000\;{\AA})/Mo(17\;{\AA})NiFe(21\;{\AA})/CoFe(28\;{\AA})/Cu(22\;{\AA})/CoFe(18\;{\AA})/IrMn(t\;{\AA})/Ta(25\;{\AA})$. Also, Mo film was deposited on Si substrates and the thermal annealing effect was analyzed. The resistivity of the Mo film was increased as an annealing temperature was increased up to $600^{\circ}C$. The variations of MR ratio were related with magnetic exchange coupling field of the spin valve structures for various IrMn pinned layer thickness up to 130 ${\AA}$. MR ratio and $H_{ex}$ of spin valves was about 9.05% and 277.5 Oe when the thickness of the IrMn pinned layer was $32.5\;{\AA}(t=32.5\;{\AA})$. It was increased to 9.65% and 337.5 Oe for $t=65\;{\AA}$. For $t=97.5\;{\AA}$, the MR ratio and Hex decreased to 8.2% and 285 Oe, and further decrease was observed up to $t=130\;{\AA}$.

• Korean Journal of Environmental Agriculture
• /
• v.4 no.2
• /
• pp.78-87
• /
• 1985

To investigate the effects of paper sludge, by-products of paper manufactory, on the chemical properties of paddy soil and growth of paddy rice, paper sludges were applied to the pots at the rates of 300, 600, 900 and 1,200㎏/l0a which were either pread-justed C/N ratio to 30 : 1 or not adjusted. The effects were compared with those of control. Seasonal variations of various forms of soil organic nitrogen, the mineralization of organic nitrogen and the contents of soil minerals were analyzed. The results were summarized as follows: 1) The contents of soil organic nitrogen, especially amino sugar-N and amino acid-N, organic matter, CEC and available $SiO_2$ were increased by application of paper sludge compared with that of control. 2) The mineralizations of organic nitrogen after 6 weeks of incubation at $30^{\circ}C$ were 12. 2, 12.6, 15.1, 9.7 and $15.2^{\circ}C$ in the control, 300㎏/l0a sludge treatment, 300㎏/l0a sludge treatment(C/N ratio adjusted), 600㎏/l0a sludge treatment and 600㎏/l0a sludge treatment(C/N ratio adjusted), respectively. 3) Cu and Pb contents in the soil were in the range of $0{\sim}0.2100$ and $0{\sim}0.0013$ ppm, respectively. Cr and Cu in the soil were not detected at all. There were no differences in the contents of all the heavy metals among all the treatments in the soil.

• Journal of the Korean Vacuum Society
• /
• v.12 no.3
• /
• pp.174-181
• /
• 2003

Ta diffusion barriers have been deposited on Si (100) substrate by applying a negative substrate bias voltage. The effect of the substrate bias voltage on the properties of the Ta films was investigated. In the case of the Ta films deposited without the substrate bias voltage, a columnar structure and small grains were observed distinctly, and the electrical resistivity of the deposited Ta films was very high (250 $\mu\Omega$cm). By applying the substrate bias voltage, no clear columnar structure and grain boundary were observed. The resistivity of the Ta films decreased remarkably and at a bias voltage of -125 V, reaching a minimum value of 40 $\mu\Omega$cm, which is close to that of Ta bulk (13 $\mu\Omega$cm). The thermal stability of Cu(100 mm)/Ta(50 mm)/Si structures was evaluated after annealing in H2 atmosphere for 60 min at various temperatures. The Ta films deposited by applying the substrate bias voltage were found to be stable up to $600^{\circ}C$, while the Ta films deposited without the substrate bias voltage degraded at $400^{\circ}C$.

• Journal of the Korean Chemical Society
• /
• v.30 no.6
• /
• pp.526-531
• /
• 1986

The stability constants of 1,15-diaza-3,4:12,13-dibenzo-5,8,11-trioxacycloheptadecane (NenOdien H$_4$, L) with transition metal ions such as $Co^{2+},\;Ni^{2+},\;Cu^{2+},\;and\;Zn^{2+}$ have been determined by potentiometry in 95% methanol solution at 25$^{\circ}$C. The complex formation of the NenOdien $_4$ with the transition metal ions depends on the basicity of the donor atoms. The order of complex stability was Co(II) < Ni(II) < Cu(II) > Zn(II). The geometries of the complexes in solid state were discussed by visible-near infrared and infrared spectrophotometry, elemental analysis and electro-conductivity. The results suggest that the geometries of the solid complexes are octahedral for $[CoL_2(OH_2)Cl]Cl{\cdot}2H_2O$, $[NiL_2(OH_2)Cl]Cl{\cdot}2H_2O$, and $[ZnLCl_2]{\cdot}\frac{1}{2}H_2O$ and square pyramidal for [CuLCl]Cl, respectively.

• The Korea Journal of Herbology
• /
• v.20 no.2
• /
• pp.17-26
• /
• 2005

Objectives : The study has been undertaken to scrutinize the results of Halloysitum Rubrum before and after physical and chemical manipulation. Methods : I used X-rays diffracted analysis system(Phillips X'Pert - MPD System) on condition of 40Kv, Anode of Cu Ka to grasp the compositions of crude Halloysitum Rubrums which have been from here and there after pulverization them below 200 mesh. X-rays fluorescence analysis system have been used to check the chief elements content of the ore on condition of 40Kv, 95mA. ICP-MS analysis system(Perkin Elmer, Elan 6100)have been used after a micro-elements and a heavy metals take advantage of mixed acid were dissolved completely. Results : The compositions of the ore Halloysitum Rubrum are composed of large amount of Halloysite and Kaolinite, and small amount of Hematite, Alum, quartzite. The chief elements content of the ore Halloysitum Rubrum are composed of Al and Si. A heavy metals in Halloysitum Rubrum are As, Cd, Cr, Cu, Pb, Zn, etc. As and Zn's amounts was lessen after physical and chemical manipulation Halloysitum Rubrum are decreased at $400^{\circ}C\;and\;450-500^{\circ}C$ each by heat analysis system. Conclusion : Results of this study show that Halloysitum Rubrum can be used in a diverse ways to treat many kinds of disease.