• 한국광물학회지
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• 제9권1호
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• pp.26-34
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• 1996

The white leather-like playgorskite occurs as a vein in the Cretaceous sedimentary rocks in the Yeongsan area, Kyeongnam, Korea. It has been investigate by means of XRD, TEM, DTA-TG, IR and chemical analysis. The palygorskite vein is composed mostly of well-crystallized palygorskite. The wall rock of the vein is altered to smectite along both sides of the vein. According to TEM observation the palygorskite shows a fibrous habit. The sizes offibers are quite variable, ranging from 0.1 to 3.0 micron in length. From XRD data, the palygorskite has orthorhombic unit cell with a=12.726$\AA$, b=17.796$\AA$, c=5.1666$\AA$. The chemical formula of the palygorskite was calculated as [Si7.93Al0.07](Al1.91Fe+30.11Mg1.96)Ca0.01O20(OH)4(OH2)2.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.533-536
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• 2006

PC-type copolymers were synthesized using MPEG(Polyethylene glycol methyl ether methacrylate, Mn=2080) to different mole ratios of mono-carboxylic acid(AA : Acylic acid). The mole ratios of AA were 2, 3, 4. To investigate effects of PC-type co-polymers on the hydration of cement, experiments involving FT-IR, XRD, SEM have been analysed with cement paste specimens to 1, 3, 28 day. The hydration reaction rate of cement paste was slightly delayed at 1 day, due to increase in molar ratio of [AA] / [MPEG], it was recovered in the days after.

• 한국해양공학회지
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• 제11권1호
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• pp.44-48
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• 1997

During studies of the ripening reaction of titanium oxalate, a new crystalline phase has been found. The crystal system was determined to be orthormbic with space group $C222_1$. The unit cell parameters were refined to a=10.503(2)$\AA$ b=15.509(3)$\AA$ c=9.7000(1)$\AA$. The chemical formula of the crystal is Ti$_{2}$O$_{2}$(C$_{2}$O$_{4}$)(OH)$_{2}$. H$_{2}$O. When heated to temperatures between 31$0^{\circ}C$ and 38$0^{\circ}C$, the material became amorphous. Heated above 41$0^{\circ}C$ converted it into anatase-type titanium dioxide.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.154-156
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• 2005

In the device structure of ITO/tris (8-hydroxyquinoline) aluminum(Alq3)/Al, we investigated the Organic Light-Emitting Diodes (OLEDs) properties as a function of the deposition rate of the $Alq_3$. The deposition rate was from 0.5 to 2.0 $[{\AA}/s]$ in a base pressure of $5{\times}10^{-6}$ [Torr]. It was found that a $Alq_3$ deposition rate of around 1.5 $[{\AA}/s]$ is the optimum for the maximum luminous properties. The optimum deposition rate of $Alq_3$ is 1.5 $[{\AA}/s]$.

• 한국세라믹학회지
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• 제12권3호
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• pp.8-12
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• 1975

The crystal structure of synthetic magnesite has been studied by X-ray method. Magnesite is trigonal R3c, with a=4.637$\AA$, c=15.023$\AA$ and Z=6. Intensity data were collected with a Rigaku automated four-circle diffractometer and Mo-K$\alpha$ radiation. The structure was refined by the full-matrix least squares method using anisotropic thermal parameters. The final R index for 234 reflections is 0.037. The C-O and Mg-O bond lengths were 1.283 and 2.105$\AA$, respectively. The interatomic angles of three kinds of O-Mg-O were 88.25, 91.75 and 180.00$^{\circ}$, respectively. It is clarified that the distortion of the Mg-O6 octahedron in magnesite is smaller than that of Ca-O6 in calcite.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1295-1297
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• 1994

At 34 at% Co-Fe, the aluminum anodic oxidized (alumite) films of particle diameter $150{\AA}$ have large perpendicular anisotropy energy and high coercive force. However, for the samples of particle diameter larger than $450{\AA}$, the bottom of each particle forms abnormal part called branch-shaped different from that of particle diameter $150{\AA}$. In this case the magnetic anisotropy energy Ku was about zero at the compositions of 45 and 75 at% Co. Furthermore, at tile compositions from 50 to 70 at% Co, the values of Ku became negative value. We confirmed that Fe-C deposited the bottom of particle orients very strongly and it has a large influence upon the magnetic anisotropy energy.

• 전자공학회논문지A
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• 제28A권5호
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• pp.380-386
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• 1991

Hydrogen plasma-assisted epitaxial(PAE) growth of GaAs/Si and GaAs/Ge/Si with Ge buffer layer has been investigated. By means of photoluminescence, Nomarski microscopu, and $\alpha$-step, it could be known that GaAs on Si with Ge buffer layer has better crystalline quality than GaAs on Si without Ge buffer layer. The stoichiometry of GaAs layer on Si was confirmed by the depth profile of Auger electron spectroscope (AES). Also the native oxide(SiO$_2$) layer on Si substrate was plama-etched and the removal of the oxide layer was confirmed by AES. Photoluminescence peak wavelength of GaAs/Ge/Si with Ge buffer of 1\ulcorner thickness and GaAs growth rate of 160$\AA$/min was 8700$\AA$and FWHM was 12$\AA$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.421-422
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• 2008

The electrical properties of OLEDs was investigated by the various cathode layer. It was measured by IVL for electrical properties and optical properties by EL spectrum. The structure of OLEDs was ITO/TPD(400$\AA$)/$Alq_3$(600$\AA$)/LiF(5$\AA$)/various cathode layer. The threshold voltage was increased by the deposited Au layer. The luminance was decreased by deposited Au layer.

• 한국전기전자재료학회논문지
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• 제11권10호
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• pp.778-783
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• 1998

Film characteristics of thin ONO dielectric layers for MONOS(metal-oxide-nitride-oxide-semiconductor) EEPROM was investigated by TEM, AES and AFM. Seocnd derivative spectra of Auger Si LVV overlapping peak provide useful information fot chemical state analysis of superthin film. The ONO film with dimension of tunnel oxide 23$\AA$, nitride 33$\AA$, and blocking oxide 40$\AA$ was fabricated. During deposition of the LPCVD nitride film on tunnel oxide, this thin oxide was nitrized. When the blocking oxide was deposited on the nitride film, the oxygen not only oxidized the nitride surface, but diffused through the nitride. The results of ONO film analysis exhibits that it is made up of $SiO_2$ (blocking oxide)/O-rich SiON(interface)/N-rich SiON(nitride)/ O-rich SiON(tunnel oxide)

• Bulletin of the Korean Chemical Society
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• 제25권1호
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• pp.122-126
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• 2004

Biofunctional nanohybrids are synthesized from layered double hydroxide (LDH) and the vitamins such as ascorbic acid and topopherol acid succinate. Either ion exchange or copricipitaion leads to successful intercalation of the vitamins into gallery space of LDH that offers a new route to safe preservation of bioactivity as well as controlled release. Intercalations of vitamins are clearly reflected on the increase in the basal spacing of ZnAl-(Nitrate) LDH from 8.5 ${\AA}$ to 10.5 ${AA}$ for ascorbate, and 49.0 ${AA}$ for tocopherol acid succinate, respectively. No significant change in UV-Vis and IR absorption characteristics of the intercalated vitamins strongly supports the safe maintenance of their bioactivities without any deterioration of chemical and structural integrity. Furthermore, it is shown that the hybridized vitamins could be discharged in a controlled kinetics.