• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.591-596
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• 2006

Topology and molecular ordering of NPD(4,4'-bis-[N-(1-naphthyl)-N-phenyl-amino]biphenyl) thin films deposited under magnetic field with post-deposition annealing were investigated. NPD was deposited onto ITO glass substrates via thermal evaporation process in vacuum. It is of great importance for highly oriented organic/metal films to have improved device performances such as higher current density and luminance efficiency. AFM (Atomic Force Microscope) and XRD (X-Ray Diffraction) analyses were used to characterize the topology and structure of oriented NPD films. The multi-source meter was used to observe the current-voltage characteristics of the ITO (Indium-Tin Oxide) / NPD (4,4'bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl) / Al (Aluminum) device. While NPD thin films deposited under magnetic field were not molecularly well aligned according to the XRD results, the films after post-deposition annealing at $130^{\circ}C$ were well-oriented. AFM images show that NPD thin films deposited under magnetic field had a smoother surface than those deposited without magnetic field. The current-voltage performance of NPD thin films was improved due to the enhanced electron mobility in the well-aligned NPD films.

• Clean Technology
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• v.23 no.2
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• pp.196-204
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• 2017

CdZnS/ZnO composite was prepared through low-temperature precipitation and drying method. The property of CdZnS/ZnO as a recyclable photocatalyst for the degradation of rhodamine B (RhB) under visible light irradiation was examined. The sample was characterized by XRD, FE-SEM, XPS, UV-vis DRS and photoluminescence techniques before and after repeated reaction to investigate the change of properties during the photocatalytic reaction. During repeated reaction, the CdZnS/ZnO showed an improved photocatalytic activity and recycle stability. Among two feasible reaction pathways for photocatalytic degradation of RhB, the cleavage of conjugated chromophore was found to predominate over N-dealkylation of chromophore skeleton in the present work. The results indicate that the CdZnS/ZnO, prepared by a simple precipitation method, can be used as a visible-light driven photocatalyst with enhanced cycle stability and activity.

• Journal of the Korean Magnetics Society
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• v.13 no.4
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• pp.165-170
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• 2003

M-type hexagonal BaFe$\sub$12/O$\sub$19/ ferrite powder was prepared by sol-gel process. The M-type hexagonal structure with ${\alpha}$ = 5.882 and c = 23.215 ${\AA}$ and its Curie temperature T$\sub$C/ was determined 780${\pm}$3 K. The isomer shifts of ,4f$_2$, 2a. 4f$_1$, 12k, and 2b were indicated 0.26, 0.24, 0.15, 0.25, and 0.24 mm/s, therefore, the valence states of the Fe ions were ferric (Fe$\^$3+/). By the law of approach to saturation (LAS), the effective anisotropy field H$\sub$A/ and crystalline anisotropy constant K$_1$ were estimated. The value of K$_1$ and H$\sub$A/ were K$_1$ = 2.5${\times}$10$\^6/erg/cm^3$ and H$\sub$A/ = 14 kOe, respectively.

• Korean Journal of Materials Research
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• v.8 no.4
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• pp.312-316
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• 1998

ZnO- TiO$_2$, and Sn0$_2$ - Ti0$_2$ ceramic composites doped with TiO$_2$ were prepared and their electrical and 1000ppm CO gas sensing properties were investigated. The phases of samples were analyzed by XRD, and the microsturctures of the fractured surface of samples were observed by SEM. A carbon monoxide gas sensitivity was de¬fined as the ratio of the resistance in dry air atmosphere(R$drt air$) to the resistance in 1000ppm CO gas atmosphere(R$_co$) The CO gas sensitivity of Smol% Ti0$_2$-added ZnO decreased about 1.7 times compared to that of pure ZnO. On the other hand, the maximum CO gas sensitivity of Ti0$_2$-added SnO$_2$ increased about 2.5 times compared to that of pure SnO$_2$. Therefore, the CO gas sensitivies of SnO$_2$-TiO$_2$ composite were better than those of ZnO- Ti0$_2$ and the temper¬ature range showing the maximum sensitivity for Sn0$_2$-TiO$_2$ composite was lower than that for ZnO- Ti0$_2$.

• Journal of the Mineralogical Society of Korea
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• v.15 no.2
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• pp.85-94
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• 2002

XRF, XRD, EPMA have been used to investigate microstructures and mineralogical changes caused by the faulting and fluids associated with faulting in the Quaternary fault gouge zones at the Sangchon, Ipsil and Wangsan faults located at the southeastern part of the Korean Peninsula. The chemical compositions of faulted rocks and protoliths analyzed by XRF show that the fault gouges are relatively enriched in TiO$_2$, P$_2$O$_{5}$, MgO, and Fe$_2$O$_3$) compared with protoliths, indicating that the fluids associated with faulting were highly activated. XRD results show that the fault gouges predominantly consist of quartz, feldspar, calcite and clay minerals. Clay minerals formed in the gouge zones are mainly composed of smectite characterized by a dioctahedral sheet. Based on EPMA analyses various kinds of sulfide, carbonate, phosphate minerals were identified in the gouge zones and protoliths. Xenotime of grey fault gouge of the Sangchon fault and sulfide minerals of contact andesitic rock of Ipsil fault and contact grey andesitic rock of Wangsan fault were probably formed by inflow of hydrothermal solution associated with faulting prior to the Quaternary. Carbonate minerals of contact andesitic rock and gouge zone of the Ipsil fault were formed by inflow of fluid associated with faulting prior to the Quaternary. They are heavily fractured and have reaction rim on their edge, indicating that faultings and inflow of fluids were highly activated after carbonate minerals were formed. Calcites of Wangsan fault seemed to be formed in syntectonic or posttectonic Quaternary faulting.g.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.200-211
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• 2022

The celadon stools with an openwork ring design which consist of four items as one collection were excavated from Gaeseong, Gyeonggi-do Province. The celadon stools were designated and managed as treasures due to their high arthistorical value in the form of demonstrating the excellence of celadon manufacturing techniques and the fanciful lifestyles during the Goryeo Dynasty. However, one of the items, which appeared to have been repaired and restored in the past, suffered a decline in aesthetic value due to the aging of the treatment materials and the lack of skill on the part of the conservator, raising the need for re-treatment as a result of structural instability. An examination of the conservation condition prior to conservation treatment found structural vulnerabilities because physical damage had been artificially inflicted throughout the area that was rendered defective at the time of manufacturing. The bonded surfaces for the cracked areas and detached fragments did not fit, and these areas and fragments had deteriorated because the adhesive trickled down onto the celadon surface or secondary contaminants, such as dust, were on the adhesive surface. The study identified the position, scope, and conditions of the bonded areas at the cracks UV rays and microscopy in order to investigate the condition of repair and restoration. By conducting Fourier-transform infrared spectroscopy(FT-IR) and portable x-ray fluorescence spectroscopy on the materials used for the former conservation treatment, the study confirmed the use of cellulose resins and epoxy resins as adhesives. Furthermore, the analysis revealed the addition of gypsum(CaSO₄·2H₂O) and bone meal(Ca₁₀ (PO₄)₆(OH)₂) to the adhesive to increase the bonding strength of some of the bonded areas that sustained force. Based on the results of the investigation, the conservation treatment for the artifact would focus on completely dismantling the existing bonded areas and then consolidating vulnerable areas through bonding and restoration. After removing and dismantling the prior adhesive used, the celadon stool was separated into 6 large fragments including the top and bottom, the curved legs, and some of the ring design. After dismantling, the remaining adhesive and contaminants were chemically and physically removed, and a steam cleaner was used to clean the fractured surfaces to increase the bonding efficacy of the re-bonding. The bonding of the artifact involved applying the adhesive differently depending on the bonding area and size. The cyanoacrylate resin Loctite 401 was used on the bonding area that held the positions of the fragments, while the acrylic resin Paraloid B-72 20%(in xylene) was treated on cross sections for reversibility in the areas that provided structural stability before bonding the fragments using the epoxy resin Epo-tek 301-2. For areas that would sustain force, as in the top and bottom, kaolin was added to Epo-tek 301-2 in order to reinforce the bonding strength. For the missing parts of the ring design where a continuous pattern could be assumed, a frame was made using SN-sheets, and the ring design was then modeled and restored by connecting the damaged cross section with Wood epos. Other restoration areas that occurred during bonding were treated by being filled with Wood epos for aesthetic and structural stabilization. Restored and filled areas were color-matched to avoid the feeling of disharmony from differences of texture in case of exhibitions in the future. The investigation and treatment process involving a variety of scientific technology was systematically documented so as to be utilized as basic data for the conservation and maintenance.

• Journal of the Korean Chemical Society
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• v.40 no.1
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• pp.28-36
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• 1996

The pentanuclear complexes have been obtained by the reactions of molybdenum(VI) and tungsten(VI) polynuclear complexes with molybdenum(O) and tungsten(O) dinitrosyl mononuclear complexes, and methylthioamidoxime. The prepared complexes (n-Bu4N)2[Mo4O12Mo(NO)2{CH3SCH2C(NH2)NHO}2{CH3SCH2C(NH)NO}2](1), (n-Bu4N)2[W4O12Mo(NO)2{CH3SCH2C(NH2)NHO}2{CH3SCH2C(NH)NO}2](2), (n-Bu4N)2[Mo4O12W (NO)2{CH3SCH2C(NH2)NHO}2{CH3SCH2C(NH)NO}2] (3) have been characterized by elemental analysis, infrared, UV-visible and 1H NMR spectra. The complexes are elucidated the cis-{M(NO)2}2+(M = Mo, W) unit and a slight delocalization by spectroscopy. The structure of (n-Bu4N)2[W4O12Mo(NO) 2{CH3SCH2C(NH2)NHO}2{CH3SCH2C(NH)NO}2] was determined by X-ray single crystal diffraction. Crystal data are follows: Monoclinic, $P21}a$, a = 22.14(2) $\AA$, b = 14.93(1) $\AA$, c = 23.20(1) $\AA$, $\beta$ = 111.08(6) $\AA$, V = 7155(9) $\AA$, Z = 4, final R = 0.072 for 6191(I > $3\sigma(I)).$ The structure of complex forms two dinuclear [W2O5{CH3SCH2C(NH2)NHO}{CH3SCH2C(NH)NO}] and a central {Mo(NO)2} 2+ core. The geometric structure of the {Mo(NO)2} 2+unit is the formally cistype and C2v symmetry.

• Applied Chemistry for Engineering
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• v.22 no.1
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• pp.21-25
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• 2011

In this study, anatase/brookite hybrid $TiO_2$ was prepared using different acid catalysts and microwave to improve photodegradation of organic pollutants. The methylene blue photodegradation properties of the prepared photocatalysts with different particle/crystal size and brookite fractions were investigated. Surface characteristics and particle sizes of anatase/brookite hybrid $TiO_2$ were evaluated using scanning electron microscopy (SEM) and laser diffraction particle size analyzer, respectively and crystal structures were investigated with X-ray diffraction (XRD). Methylene blue photodegradation properties were evaluated with UV-vis spectrophotometer. Anatase and anatase/brookite hybrid $TiO_2$ had less than 500 nm size of clusters and the average particle size of $6.66{\sim}6.85{\mu}m$, suggesting that types of acid catalysts did not affect the size. XRD of the prepared $TiO_2$ showed that the photocatalysts had anatase/brookite hybrid crystal structure and applying microwave did not change their crystal structure. Photodegradation of methylene blue with the prepared photocatalyst did not increased proportionally to the fraction of brookite and the crystal size and decreased when brookite fraction and the crystal size increased further. Anatase/brookite hybrid $TiO_2$ with brookite fraction of 9.4% and crystal size of 4.53 nm shows the best photodegradation activity of methylene blue.

• Journal of the Mineralogical Society of Korea
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• v.7 no.1
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• pp.62-79
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• 1994

The quanttative and structural analysis of the binary standard mixtures of albite and quartz, and microcline and albite were carried out using the Rietveld refinement method in order to investigate the accuracy and precision of the method. The quantitative analysis using the Rietveld method results in a standard deviation of 4 wt % for the albite-quartz standard mixtures and 1 wt % for the microcline-albite standard mixtures, suggesting that its accuracy is far better than that of the conventional XRD method in which only a few selected peaks are utilized. Furthermore, the unit-cell parameters of component minerals in mixtures were also estimated accurately during the analysis. It was observed that the refined weight fractions deviate systematically from their measured values when the method is applied to the mixtures that contain minerals with different degrees of preferred orientation, such as albite-quartz mixtures. The preferred orientation parameters and R-values suggest that the systematic deviation is caused as a result of the preferred orientation effect of feldspar crystallites. It is evident that the preferred orientation corrections are of help for the accurate determination of unit-cell parameters, although they may not improve the result of quantitative analysis significantly. The refined weight fraction of the mineral with higher degree of preferred orientation in mixture is greater than the measured one. This is apparently caused by the effect of geometry of feldspar crystallites in the surface of the mounted sample. The Rietveld refinement method minimizes the problems inherent in the traditional XRD methods, such as the line overlap, primary extinction, and preferred orientation effect, by fitting every data point in a whole pattern explicitly. Furthermore, accurate unit-cell parameters as well as scale factors that can be obtained from the Rietveld refinement are used for the quqantification. The present stdudy demonstrates that the Rietveld method yields far more accurate analytical result than the conventional XRD quantitative analysis method does.

• Korean Journal of Heritage: History & Science
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• v.51 no.2
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• pp.78-91
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• 2018

Sangjogam, located in Goseong, Gyeongsangnam-do, was designated as Natural Monument #411, because of its diverse geological heritage, such as fossils, ripple marks, dykes, and columnar joints. In the area, Byeongpungbawi, with its beautiful columnar joints vertical to the bedding plane of the underlying sedimentary rocks and spectacular coastal view, was named after its overall shape reminiscent of a huge folding screen. The purpose of this study was to investigate the formation process of the columnar joints using the anisotropy of magnetic susceptibility (AMS) method. AMS measurements showed that the k1 and k3 values representative of directions of the long and short axes of a magnetic particle at each point strongly clustered, and the oblate magnetic foliation structure in Byeongpungbawi developed during sill-type intrusion rather than lava flow. In summary, Byeongpungbawi was produced by sill-type intrusion along the bedding plane of the underlying sedimentary layer, and the subsequent formation of columnar joints was accompanied by the cooling and contraction of intruding rhyolite magma. This study potentially provides a basic research tool in understanding the formation mechanism of columnar joints which are widely distributed in southern Korea.