• Bulletin of the Korean Chemical Society
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• v.27 no.8
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• pp.1140-1144
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• 2006

A macrocyclic ligand, N,N',N'-tribenzyl-2,11,20-triaza[3,3,3](2,6)pyridinophane (BAPP), was used to prepare an iron(II) complex as a nonheme model complex, $[(BAPP)Fe]^{+2}$ (1). X-ray crystallography of a colorless crystal of 1 revealed that BAPP acted as a pentadentate ligand due to geometrical strain for the formation of a six-coordinate iron(II) complex by BAPP. As a result, the iron center revealed a significantly distorted square pyramidal geometry similar to that found in the active site of taurine dioxygenase (tauD). In the reaction of 1 with PhIO, no intermediate was observed in the UV-visible region of spectrometer at low temperatures. Catalytic oxidations of triphenyl phosphine with PhIO at ${-40^{\circ}C}$ revealed that 1 was able to convert triphenyl phosphine to triphenyl phosphine oxide.23; SSOCHKThioanisole was also oxidized to the corresponding methylphenyl sulfoxide under the same conditions.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.8
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• pp.74-86
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• 1994

In this paper a hierarchical stereo matching algorithm to obtain the disparity in wavelet transformed domain by using locally adaptive window and weights is proposed. The pyramidal structure obtained by wavelet transform is used to solve the loss of information which the conventional Gaussian or Laplacian pyramid have. The wavelet transformed images are decomposed into the blurred image the horizontal edges the vertical edges and the diagonal edges. The similarity between each wavelet channel of left and right image determines the relative importance of each primitive and make the algorithm perform the area-based and feature-based matching adaptively. The wavelet transform can extract the features that have the dense resolution as well as can avoid the duplication or loss of information. Meanwhile the variable window that needs to obtain precise and stable estimation of correspondense is decided adaptively from the disparities estimated in coarse resolution and LL(low-low) channel of wavelet transformed stereo image. Also a new relaxation algorithm that can reduce the false match without the blurring of the disparity edge is proposed. The experimental results for various images show that the proposed algorithm has good perfpormance even if the images used in experiments have the unfavorable conditions.

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1781-1786
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• 2007

Two copper(II) complexes, [CuL3](ClO4)2 bearing one N-CH2CH2CONH2 group as well as one N-CH2CH2CN group and [CuL4](ClO4)2 bearing two N-CH2CH2CONH2 groups, have been prepared by the selective hydrolysis of [CuL2](ClO4)2 (L2 = C-meso-1,8-bis(cyanoethyl)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). The complex [CuL5](ClO4)2 bearing one N-CH2CH2C(=NH)OCH3 and one N-CH2CH2CN groups has been prepared as the major product from the reaction of [CuL2](ClO4)2 with methanol in the presence of triethylamine. In acidic aqueous solution, the N-CH2CH2C(=NH)OCH3 group of [CuL5](ClO4)2 undergoes hydrolysis to yield [CuL6](ClO4)2 bearing both N-CH2CH2COOCH3 and N-CH2CH2CN groups. The crystal structure of [CuL5](ClO4)2 shows that the complex has a slightly distorted square-pyramidal coordination polyhedron with an apical Cu-N (N-CH2CH2C(=NH)OCH3 group) bond. The apical Cu-N bond distance (2.269(3) A) is ca. 0.06 A longer than the apical Cu-O (N-CH2CH2CONH2 group) bond of [CuL4](ClO4)2. The pendant amide group of [CuL3](ClO4)2 is involved in coordination. The carboxylic ester group of [CuL6](ClO4)2 is also coordinated to the metal ion in various solvents but is removed from the coordination sphere in the solid state.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.1
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• pp.59-65
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• 2012

A study on the electrical characteristic analysis of solar cell diodes under experimental conditions of varying temperature and frequency has been conducted. From the current-voltage (I-V) measurements, at the room temperature, we obtained the ideality factor (n) for Space Charge Region (SCR) and Quasi-Neutral Region (QNR) of 3.02 and 1.76, respectively. Characteristics showed that the value of n (at SCR) decreases with rising temperature and n (at QNR) increases with the same conditions. These are due to not only the sharply increased SCR current flow but the activated carrier recombination in the bulk region caused by defects such as contamination, dangling bonds. In addition, from the I-V measurements implemented to confirm the junction uniformity of cells, the average current dispersion was 40.87% and 10.59% at the region of SCR and QNR, respectively. These phenomena were caused by the pyramidal textured junction structure formed to improve the light absorption on the device's front surface, and these affect to the total diode current flow. These defect and textured junction structure will be causes that solar cell diodes have non-ideal electrical characteristics compared with general p-n junction diodes. Also, through the capacitance-voltage (C-V) measurements under the frequency of 180 kHz, we confirmed that the value of built-in potential is 0.63 V.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1038-1041
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• 2003

In the paper, we investigated silicon surface microstructures formed by reactive ion etching in hollow cathode system. Wet anisotropic chemical etching technique use to form random pyramidal structure on <100> silicon wafers usually is not effective in texturing of low-cost multicrystalline silicon wafers because of random orientation nature, but High density hollow cathode plasma system illustrates high deposition rate, better film crystal structure, improved etching characteristics. The etched silicon surface is covered by columnar microstructures with diameters form 50 to 100nm and depth of about 500nm. We used $SF_{6}$ and $O_{2}$ gases in HCP dry etch process. This paper demonstrates very high plasma density of $2{\times}10^{12}$ $cm^{-3}$ at a discharge current of 20 mA. Silicon etch rate of 1.3 ${\mu}s/min$. was achieved with $SF_{6}/O_{2}$ plasma conditions of total gas pressure=50 mTorr, gas flow rate=40 sccm, and rf power=200 W. Our experimental results can be used in various display systems such as thin film growth and etching for TFT-LCDs, emitter tip formations for FEDs, and bright plasma discharge for PDP applications. In this paper we directed our study to the silicon etching properties such as high etching rate, large area uniformity, low power with the high density plasma.

• Journal of Broadcast Engineering
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• v.4 no.2
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• pp.144-154
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• 1999

The binomial sequences are family of orthogonal sequences that can be generated with remarkable simplicity-no multiplications are necessary. This paper introduces a class of non-recursive multidimensional filters for frequency-selective image processing without multiplication operations. The magnitude responses are narrow-band. approximately gaussian-shaped with center frequencies which can be positioned to yield low-pass. band-pass. or high-pass filtering. Algorithms for the efficient implementation of these filters in software or in hardware are described. Also. we show that the binomial QMFs are the maximally flat magnitude square Perfect Reconstruction paraunitary filters with good compression capability and these are shown to be wavelet filters as well. In wavelet transform the original image is decomposed at different scales using a pyramidal algorithm architecture. The decomposition is along the vertical and horizontal direction and maintains constant the number of pixels required to describe the images. An efficient perfect reconstruction binomial QMF-Wavelet signal decomposition structure is proposed. The technique provides a set of filter solutions with very good amplitude responses and band split. The proposed binomial QMF-filter structure is efficient, simple to implement on VLSl. and suitable for multi-resolution signal decomposition and coding applications.

• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1747-1751
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• 2006

The dinuclear tetraazadiphenol macrocyclic nickel(II) complexes [$Ni_2$([20]-DCHDC)]$Cl_2$ (I), [$Ni_2$([20]-DCHDC)]$(ClO_4)_2{\cdot}2CH_3CN $ (II(b)) and [$Ni_2$([20]-DCHDC)$(NCS)_2$] (III) {$H_2$[20]-DCHDC = 14,29-dimethyl-3,10,18,25-tetraazapentacyclo-[25,3,1,$0^{4,9}$,$1^{12,16}$,$0^{19,24}$]ditriacontane-2,10,12,14,16(32),17,27(31), 28,30-decane-31,32-diol} have been synthesized by self-assembly and characterized by elemental analyses, conductances, FT-IR and FAB-MS spectra, and single crystal X-ray diffraction. The crystal structure of II(b) is determined. It crystallizes in the monoclinic space group P2(1)/c. The coordination geometries around Ni(II) ions in I and II(b) are identical and square planes. In complex III each Ni(II) ion is coordinated to $N_2O_2$ plane from the macrocycle and N atoms of NCS- ions occupying the axial positions, forming a square pyramidal geometry. The nonbonded Ni…Ni intermetallic separation in the complex II(b) is 2.8078(10) $\AA$. The FAB mass spectra of I, II and III display major fragments at m/z 635.1, 699.4 and 662.4 corresponding to [$Ni_2$([20]-DCHDC)(Cl + 2H)]$^+$, [$Ni_2$([20]-DCHDC)$(ClO_4\;+\;2H)]^+$ and [$Ni_2$([20]-DCHDC)(NCS) + 6H]$^+$, respectively.

• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.191-196
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• 1989

We obtained the new complexes, $Fe{\eta}^4-R,R'-TPSCp](CO)_3$(R,R'-TPSCp = 1,1-disubstituted 2,3,4,5-Tetraphenyl-1-Silacyclopenta-2,4-diene; R = Ph, R' = Cl, R = R' = Cl) from the reaction of the corresponding R,R'-TPSCp with ironpentacarbonyl under reflux in toluene. Also, the analogous complexes with R = R' = Me and R = Me, R' = Cl were obtained in an identical manner. We have determined the crystal structure of $Fe[Ph(Cl)-TPSCp](CO_)3$ by using Mo ka, ${\lambda}$ = 0.71069${\AA}$, where the unit cell was found to be monoclinic with a = 9.042 (6)${\AA}$, b = 19.870 (9)${\AA}$, c = 17.426 (9)${\AA}$ and ${\beta}$ = 96.28(4)$^{\circ}$. The butadiene moiety of TPSCp ring is planar and the dihedral angle of the butadiene plane and C4-Si-C25 plane was opened up to 41.8$^{\circ}$. The C-C distances in the butadiene moiety were found to be 1.4346, 1.462, and 1.440 ${\AA}$, respectively. It may be said that the four ${\pi}$-electrons are delocalized over the four carbons in five membered ring through coordination with ironcarbonyl. In this complex Fe is either in distorted tetrahedron environment with the centroid of the four C-atom butadiene moiety and three carbons of the three carbonyls or in distorted square-pyramidal environment with two midpoints of double bonds of the butadiene moiety and two carbons of carbonyl defining the base of the pyramid and the carbon of remaining carbonyl the apex.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.4
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• pp.347-353
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• 2002

A structure of a glass electrode-type pH sensor for measuring any concentration of $H^+$ in an aqueous solution was embodied with bulk micromachining technology. Two open well structures were formed, and a reference electrode was secured by the Ag/AgCl thin film in the sloped side of the etched structure. A sensitive membrane of an indicator electrode for generating a potential by an exchange reaction to $H^+$ was made with a glass containing Na 20% or more finely so that its thickness might be $100{\mu}m$ or so, and then it was bonded to one pyramidal structure. A liquid junction for a current path was formed by filling an agar in the anisotropically etched part of the Si wafer, which had a size of $50{\mu}m{\times}50{\mu}m$, and then bonded it to the other. After complete fabrication of each part, it was filled with a 2M KCl reference solution and encapsulated the sensor structure with a cold expoxy. The potential value of fabricated pH sensor was about 90mV/pH in the standard pH solutions.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.5
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• pp.168-173
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• 2020

To analyze and describe the behavior and mechanisms occurring in the thermal oxidation process of AlN, bulk AlN single crystals were thermally treated with different temperatures. As a result, it was confirmed that full-scale oxidation of bulk AlN and growth of Al-oxide occurred from the temperature of 800℃, which confirmed that the weight% of O elements tended to increase while the N elements decreased with increasing the temperature. In the case of thermal treatment at 900℃, the grown Al-oxides were merged with neighboring Al-oxides and began to form α-Al₂O₃ poly-crystals. During thermal treatment at the temperature of 1000℃, hexagonal pyramidal shaped poly-crystalline α-Al₂O₃ was clearly observed. Through the X-ray diffraction pattern analysis, the changes of surface crystal structure according to the temperature of bulk AlN were investigated in detail.