• Journal of the Korean Chemical Society
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• v.57 no.3
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• pp.352-356
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• 2013

In this work, a new cadmium complex $[Cd(L)(CH_3COO)_2].2H_2O$ (1) with the ligand L, N,N'-bis(2-pyridinecarboxalidene)-1,2-cyclohexanediamine was prepared and identified by elemental analysis, FT-IR, Raman, $^1H$ NMR spectroscopy and single-crystal X-ray diffraction. The cadmium atom in the crystal structure of 1 has distorted triangular dodecahedral geometry by coordination of the four nitrogen atoms of L and four oxygen atoms of the two acetate ions. Two water molecules are also incorporated in the crystal network. The $O-H{\cdots}O$ hydrogen bonds present in the crystal structure of 1. In this work, three structural surveys including coordination numbers of the cadmium atom, coordination modes of L and resonance in pyridine-2-ylmethanimine-based compounds are presented.

• Journal of the Korean Magnetic Resonance Society
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• v.8 no.1
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• pp.19-27
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• 2004

C-terminal fragments of APP (APP-CTs), that contain complete Abeta sequence, are found in neuritic plaques, neurofibrillary tangles and the cytosol of lymphoblastoid cells obtained from AD patients. CT16, Lys649-Asp664 (KKQYTSIHHGVVEVD) has been known as the most toxic part in the C-terminal fragment of amyloid precursor protein (APP). The solution structure of CT16 was investigated using NMR spectroscopy in various membrane-mimicking environments. According to Circular Dichroim (CD) spectra, CT16 has a random structure in aqueous solution, while conformational change was induced by addition of TFE and SDS micelle. Tertiary structure as determined by NMR spectroscopy shows that CT16 has a ${\beta}$-turn conformation in trifluoroethanol-containing aqueous solution.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.341-350
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• 1996

The CdS thin films are grown on quartz plate by hot wall epitaxy. The source and substrate temperature is $590^{\circ}C$ and $400^{\circ}C$ respectively, and thickness of the film is $2.5\;\mu\textrm{m}$. Using extrapolation method of X-ray diffraction patterns for the CdS thin film, it was found hexagonal structure whose lattice constant a and c were $4.137\;{\AA}$ and $6.713\;{\AA}$, respectively. Hall effect on this sample was measured by the method of van der Pauw and studied on cattirer density and mobility depending on temperature. From hall data, the mobility was likely to be decreased by piezoelectric scattering in the temperature range 30 K to 200 K and by polar optical scattering in the temperature range 200 K to 293 K. In order to explore the applicability as a photoconductive cell we measured the sensitivity ($\gamma$), the ratio of photocurrent to darkcurrent (pc/dc), maximum allowable power dissipation (MAPD), spectral response and response time. The results indicated that for the samples annealed in Cu vapor the photoconductive characteristics are the best. Then we obtained the sensitivity of 0.99, the value of pc/dc of $9.42{\times}10^{6}$, the MAPD of 318 mW, and the rise and decay time of 10 ms and 9 ms, respectively.

• Journal of the Korean Magnetics Society
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• v.15 no.3
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• pp.167-171
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• 2005

Detailed aspects of the charge disproportionation (CD) transition for a polycrystalline $La_{1/3}Sr_{2/3}FeO_{2.96}$ were studied with the X-ray diffraction, $M\ddot{o}ssbauer$ spectroscopy, and SQUID magnetometer. The crystal structure was found to be rhombohedral with a space group R/3c. The lattice parameters were $a_R=5.4874\;\AA,\;and\;a_R=60.07^{\circ}$, respectively. $M\ddot{o}ssbauer$ spectra were taken within a wide range of temperature from 4.2 K up to room temperature. In the low temperature region, the spectra were comprised of two superimposed sextets which originated from $Fe^{3+}\;and\;Fe^{5+}$, respectively. This was the antiferromagnetic mixed valence state produced by the charges disproportionated into two different species. In the high temperature region, however, only a singlet from $Fe^{3.6+}$ was observed, indicating that it was a paramagnetic averaged valence state. The CD transition occurred in the temperature range from 175 K to 200 K, in which the two phases coexisted. The origin for the CD transition was explained by the thermally generated fast hopping of electrons. Hysteresis loop showed that there existed a strong antiferromagnetic interaction among magnetic ions. As the temperature increased thru the CD transition temperature, it was very likely that the interaction between $Fe^{3+}\;and\;Fe^{5+}$ was replaced by a more stronger one.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.2
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• pp.127-131
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• 2004

A low-cost, simple strip reader system using a linear movement mechanism of CD-ROM deck has been developed to characterize a lateral flow membrane-based immunochromatographic assay. The test strip reader was assembled by a CD-ROM deck and home-made optical head especially designed for immunoassays. The optical head for detecting reflected light from the test strip surface consists of green light-emitting diode, large area silicon photodiode, and anodized aluminum mounting block providing a slit structure for cutting light from the LED. The stepping motor of the deck was operated in the full step mode, whose distance of each reading point is about 0.15mm. The performance of the strip reader was tested by analysis of HBV(hepatitis B virus) antigen test kit. This strip reader can be useful for inexpensive, disposable, and membrane-based assays that provide visual evidence of the presence of an analyte in a liquid sample.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.2138-2142
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• 2013

Two new 3D coordination complexes [Cd(3-bpcd)(pht)] (1) and [Zn(3-bpcd)(pht)] (2) [3-bpcd = N,N'-bis(pyridin-3-yl)cyclohexane-1,4-dicarboxamide, $H_2pht$ = phthalic acid] have been hydrothermally synthesized. X-ray diffraction analysis reveals that the complexes 1 and 2 represent a 4-connected diamondoid topology with a 3-fold interpenetrating feature. Moreover, the fluorescent properties of complexes 1 and 2 are studied.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.620-622
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• 2004

In this study, a mono-chelated compound as novel blue light emitting material, $BPh_2$(pbi) (pbi = 2-(2-Pyridyl)benzimidazole) was synthesized Organic light emitting Diodes (OLEDs), which has a ITO/NPB(40 nm)/Boron(30 nm)/$Alq_3$(1 nm)/Liq(3 nm)/Al(150 nm) structure, has been fabricated. The maximum brightness of the device is up to about 900 cd/$m^2$ and 0.54 cd/A at 11.5 V. The EL peaks and CIE coordinates of our OLEDs is 457 nm and (0.26, 0.29), respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.579-581
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• 2004

A new DCM derivative containing the phenoxazine moiety (DCPXZ) has been synthesized for use as a red fluorescent dye molecule in organic light-emitting diodes (OLEDs). The photoluminescence and electroluminescence properties of DCPXZ were examined. The maximum photoluminescence of DCPXZ in chloroform solution ($10^{-5}$ mol) was observed at 616 nm. EL devices were fabricated with the structure ITO/PEDOT-PSS/Cu-PC(15nm)/${\alpha}$-NPD(45nm)/$Alq_3$:DCPXZ(30nm)/$Alq_3$(30nm)/LiF(0.5nm)/Al. The maximum EL emission for the 2.0% DCPXZ-doped device was at 608 nm with CIE coordinates (0.57, 0.42). The EL device exhibited a maximum brightness of 15,000 cd/$m^2$ at 19.4 V and a power efficiency of 1.04 lm/W at a luminance of 100 cd/$m^2$.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1018-1023
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• 2006

The metal chelate complex of aluminum 8-hydroxyquinolines $(Alq_3)$ is an important electro-luminescent (EL) material used in fabricating organic light emitting (OLEDs). In this work, diodes / displays using in house synthesized $Alq_3$ and simple structure have been fabricated. It is demonstrated that luminance of $12460\;cd/m^2$ and efficiency of 3.1 cd/A are achievable in these fluorescent devices. Possible degradation effects are analyzed.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1577-1582
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• 2006

Tandem OLED structures formed by connecting two or more low-voltage electroluminescent units (stacks) are effective for achieving high efficiency at low current density as well as long operational lifetime. We have fabricated white emitting tandem structures with two or three low-voltage white-emitting stacks using transparent organic "PN"-type connectors. Three- stack white tandem structures with efficiency greater than 24 cd/A at D65 and operational stability of about 110,000 h. (extrapolated) at $1000\;cd/m^2$ have been demonstrated. With a stacked structure, the power consumption for displays using an RGBW format can be reduced by 25% compared to previously described formulations. We have also fabricated advanced white tandem structures where the color gamut (NTSC x,y ratio) has been improved to greater than 70% using standard color filters. The white OLEDs can also be used to increase the colorrendering index CRI (>80%), an important consideration for solid-state lighting.