• Journal of the Korean Chemical Society
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• v.29 no.3
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• pp.239-246
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• 1985

The equilibria of chemical reaction between [Cu(dl-trans-[14]-diene)]$^{2+}$ and L$^{n-}$(S$_2$O$_3^{2-}$, SCN$^-$, I$^-$, NO$_2^-$) ions were studied by the spectrophotometric method in the range of 15 to 35$^{\circ}C$ and 1 to 1500bar. The equilibrium constants(K) for L$^{n-}$ = S$_2$O$_3^{2-}$, SCN$^-$, I$^-$ and NO$_2^-$ ions at 25$^{\circ}C$ and 1500bar were 3.0, 1.9, 0.6 and 0.5, respectively. The values of K decreased with increasing pressure and temperature. From the temperature effect on equlibrium constant, the thermodynamic parameters(${\Delta}G^{\circ}$, ${\Delta}H^{\circ}$, ${\Delta}S^{\circ}$) of reaction were evaluated and the reactions of [Cu(dl-trans-[14]-diene)]2+ ion with S$_2$O$_3^{2-}$, SCN$^-$ and I$^-$ except NO$_2^-$ ion were exothermic. The volume changes of reaction(${\Delta}$V) had positive values for all the used anions. The values of ${\Delta}$V in cm$^3$/mole for S$_2$O$_3^{2-}$ ion at 1,500, 1,000 and 1,500bar were 26, 22, 19 and 16, and those for S$_2$O$_3^{2-}$, SCN$^-$, I$^-$ and NO$_2^-$ ions at atmospheric pressure 26, 30, 64 and 45, respectively. Bonding character between Cu(Ⅱ)-complex ion and L$^{n-}$ was discussed by comparing both the equlibrium constants experimentally determined and those calculated according to Fuoss's ion-pair equation in case of S$_2$O$_3^{2-}$ ion.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.169-181
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• 2007

Statement of problem: Titanium is well known as a proper metal for the dental restorations, because it has an excellent biocompatibility, resistance to corrosion, and mechanical property. However, adhesion between titanium and dental porcelains is related to the diffusion of oxygen to the reaction layers formed on cast-titanium surfaces during porcelain firing and those oxidized layers make the adhesion difficult to be formed. Many studies using mechanical, chemical and physical methods to enhance the titanium-ceramic adhesion have been actively performed. Purpose: This study meant to comparatively analyse the adhesion characteristics depending on different titanium surface coatings after coating the casts and wrought titanium surfaces with Au and TiN. Material and method: In this study, the titanium specimens (CP-Ti, Grade 2, Kobe still Co. Japan) were categorized into cast and wrought titanium. The wrought titanium was cast by using the MgO-based investment(Selevest CB, Selec). The cast and wrought titanium were treated with Au coating($ParaOne^{(R)}$., Gold Ion Sputter, Model PS-1200) and TiN coating(ATEC system, Korea) and the ultra low fusing dental porcelain was fused and fired onto the samples. Biaxial flection test was done on the fired samples and the porcelain was separated. The adhesion characteristics of porcelain and titanium after firing and the specimen surfaces before and after the porcelain fracture test were observed with SEM. The atomic percent of Si on all sample surfaces was comparatively analysed by EDS. In addition, the constituents of specimen surface layers after the porcelain fracture and the formed compound were evaluated by X-ray diffraction diagnosis. Result: The results of this study were obtained as follows : 1. The surface characteristics of cast and wrought titanium after surface treatment(Au, TiN, $Al_2O_3$ sandblasting) were similar and each cast and wrought titanium showed similar bonding characteristics. 2. Before and after the biaxial flection test, the highest atomic weight change of Si component was found in $Al_2O_3$ sandblasted wrought titanium(28.6at.% $\rightarrow$ 8.3at.%). On the other hand, the least change was seen in Au-Pd-In alloy(24.5at.% $\rightarrow$ 9.1at.%). 3. Much amount of Si components was uniformly distributed in Au and TiN coated titanium, but less amount of Si's was unevenly dispersed on Al2O3 sandblasting surfaces. 4. In X-ray diffraction diagnosis after porcelain debonding, we could see $Au_2Ti$ compound and TiN coating layers on Au and TiN coated surfaces and $TiO_2$, typical oxide of titanium, on all titanium surfaces. 5. Debonding of porcelain on cast and wrought titanium surface after the biaxial flection is considered as a result of adhesion deterioration between coating layers and titanium surfaces. We found that there are both adhesive failure and cohesive failure at the same time. Conclusion: These results showed that the titanium-ceramic adhesion could be improved by coating cast and wrought titanium surfaces with Au and TiN when making porcelain fused to metal crowns. In order to use porcelain fused to titanium clinically, it is considered that coating technique to enhance the bonding strength between coating kKlayers and titanium surfaces should be developed first.

• Journal of Adhesion and Interface
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• v.13 no.3
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• pp.137-144
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• 2012

Chemical functionalization of carbon nanomaterials (CNMs) is generally carried out for increasing interfacial adhesion between filler and polymer matrix for CNM-polymer nanocomposites. The chemically functionalized CNTs can produce strong interfacial bonds with many polymers, allowing CNT based nanocomposites to possess high mechanical and functional properties. Hence, increased surface adhesion can be measured indirectly by observing increased mechanical properties. However, there is a more direct way to observe interfacial bonds between polymer and CNM by measuring piezoresistivity behavior so that we can imagine the behavior of CNM particles in polymer matrix under deflection. Fuctionalization of MWCNT and rGO was carried out by oxidization reaction of MWCNT and rGO with $H_2SO_4/HNO_3$ solution. Electrical resistivities of MWCNT-PMMA and rGO-PMMA composites were decreased after functionalization because of the destructive fuctionalization process. Meanwhile, piezoresistivities of functionalized CNM-PMMA composites showed more sensitive behavior under the same deflection as compared to pristine CNM-PMMA composites. Therefore, mobility of CNM in polymer matrix was found to be improved with chemical functionalization.

• Clean Technology
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• v.19 no.2
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• pp.165-172
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• 2013

In this study, the hydrogen chloride removal using K-based dry sorbents ($K_2CO_3/Al_2O_3$, KEPRI, Korea) was studied with varying the pressure in a fixed bed reactor (15 cm tall bed with 0.5 cm I.d.). Working temperature was $400^{\circ}C$ and feed gas concentration was 750 ppm (HCl vol%, $N_2$ balance). The chloride sorption capacity of sorbent increases with increasing pressure (1, 5, 10, 15 and 20 bar). Also, after forming KCl crystal by reaction with $K_2CO_3$ and HCl, owing to the strong bonding energy, sorbent regeneration was practically impossible. Its optical, physical and chemical characterizations were evaluated by SEM, EDAX, BET, TGA and XRD. At $400^{\circ}C$ and 20 bar condition, working condition for the dehalogenation process after gasification, K-based dry sorbent showed high HCl sorption capacity and HCl/$N_2$ separation performances comparing with Ca-based and Mg-based dry sorbents.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.3
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• pp.171-180
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• 2015

This study was performed on the removal of Cs, one of the main high- radioactive nuclides contained in the high-radioactive seawater waste (HSW), by adsorption with IE911 (crystalline silicotitanate type). For the effective removal of Cs and the minimization of secondary solid waste generation, adsorption of Cs by IE911 (hereafter denoted as IE911-Cs) was effective to carry out in the m/V (ratio of absorbent weight to solution volume) ratio of 2.5 g/L, and the adsorption time of 1 hour. In these conditions, Cs and Sr were adsorbed about 99% and less than 5%, respectively. IE911-Cs could be also expressed as a Langmuir isotherm and a pseudo-second order rate equation. The adsorption rate constants (k₂) were decreased with increasing initial Cs concentrations and particle sizes, and increased with increasing ratios of m/V, solution temperatures and agitation speeds. The activation energy of IE911-Cs was about 79.9 kJ/mol. It was suggested that IE911-Cs was dominated by a chemical adsorption having a strong bonding form. From the negative values of Gibbs free energy and enthalpy, it was indicated that the reaction of IE911-Cs was a forward, exothermic and relatively active at lower temperatures. Additionally, the negative entropy values were seen that the adsorbed Cs was evenly distributed on the IE911.

• Journal of the Korean Chemical Society
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• v.47 no.4
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• pp.391-400
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• 2003

This study was performed the analysis of seven kinds of the hight school chemistry II textbooks based on the 6th curriculum. Particularly, inquiry activity part was analyzed by the three dimension framework which consists of inquiry content dimension, inquiry process dimension and inquiry context dimension. In the analysis of the inquiry content dimension of inquiry activities, the total number of themes in seven kinds of textbook was 212. And the number of inquiry activities in seven kinds of textbook was diverse: A textbook had 28, B textbook 25, C textbook 31, D textbook 35, E textbook 31, F textbook 29 and G textbook 33. As for the avaerage number of inquiry activities of each chapter, chapter I "Material Science" is 3.00(9.91${\%}$), chapter II "Atomic Structure and Periodic Table" 4.57(15.1${\%}$), chapter III "Chemical Bonding and Compound" 6.86(22.6${\%}$), chapter IV "State of Matter and Solution" 7.00(23.1${\%}$), chapter V "Chemical Reaction" 8.86(29.2${\%}$). For the analysis of inquiry process dimension, it follows in the order of 'observation and measuring (66.7${\%}$)', 'Interpreting data and formulating generalizations (26.5${\%}$)', 'seeing a problem and seeking ways to solve it (4.1%)', and 'building, testing and revising the theoretical model (2.7${\%}$)'. As for the analysis of the inquiry context dimension, the scientific context occupied 90.5${\%}$, the individual context 4.3${\%}$, the social context 0.9${\%}$, and the technical context 4.3${\%}$. It shows that the proportion of STS(Science-Technology-Society) related contents in inquiry activities was only 9.5${\%}$.

• Bulletin of the Korean Chemical Society
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• v.26 no.12
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• pp.1946-1952
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• 2005

New group 15 organometallic compounds, M$(phenanthrenyl)_3$ (M = P (1), Sb (2), Bi (3)) have been prepared from the reactions of 9-phenanthrenyllithium with $MCl_3$. A reaction of 9-(diphenylphosphino)phenanthrene with 2,6-diisopropylphenyl azide led to the formation of (phenanthrenyl)${(Ph)}_2P$=N-(2,6-$^iPr_2C_6H_3$) (4). The crystal structures of 2 and 4 have been determined by single-crystal X-ray diffractions, both of which crystallize with two independent molecules in the asymmetric unit. Compound 2 shows a trigonal pyramidal geometry around the Sb atom with three phenanthrenyl groups being located in a screw-like fashion with an approximately $C_3$ symmetry. A significant amount of CH- -$\pi$ interaction exists between two independent molecules of 4. The phosphorus center possesses a distorted tetrahedral environment with P-N bond lengths of 1.557(3)$\AA$ (P(1) N) and 1.532(3)$\AA$ (P(2)-N), respectively, which are short enough to support a double bond character. One of the most intriguing structural features of 4 is an unusually diminished bond angle of C-N-P, attributable to the hydrogen bonding of N(1)-H(5A) [ca. 2.49$\AA$ between two adjacent molecules in crystal packing. The compounds 1-3 show purple emission both in solution and as films at room temperature with emission maxima ($\lambda_{max}$) at 349, 366, and 386 nm, respectively, attributable to the ligand centered $\pi$ $\rightarrow$ $\pi^\ast$ transition in phenanthrene contributed by the lone pair electrons of the Gp 15 elements. Yet the nature of luminescence observed with 4 differs in that it originates from $\pi$ (diisopropylbenzene)-$\pi^\ast$ (phenanthrene) transitions with the $\rho\pi$contribution from the nitrogen atom. The emission maximum of 4 is red-shifted ranging 350-450 nm due to the internal charge transfer from the phenanthrenyl ring to the N-arylamine group as deduced from the ab initio calculations.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.24.1-24.1
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• 2009

Tantalum carbo-nitride($T_aC_xN_y$) films were deposited with chemical vapor deposition(CVD) using tert-butylimido tris-diethylamido tantalum (TBTDET, $^tBu-N=Ta-(NEt_2)_3$, $Et=C_2H_5$, $^tBu=C(CH_3)_3$) between $350^{\circ}C$ and $600^{\circ}C$ with argon as a carrier gas. Fourier transform infrared (FT-IR)spectroscopy was used to study the thermal decomposition behavior of TBTDET in the gas phase. When the temperature was increased, C-H and C-N bonding of TBTDET disappeared and the peaks of ethylene appeared above $450^{\circ}C$ in the gas phase. The growth rate and film density of $T_aC_xN_y$ film were in the range of 0.1nm/min to 1.30nm/min and of $8.92g/cm^3$ to $10.6g/cm^3$ depending on the deposition temperature. $T_aC_xN_y$ films deposited below $400^{\circ}C$ were amorphous and became polycrystal line above $500^{\circ}C$. It was confirmed that the $T_aC_xN_y$ film was a mixture of TaC, graphite, $Ta_3N_5$, TaN, and $Ta_2O_5$ phases and the oxide phase was formed from the post deposition oxygen uptake. With the increase of the deposition temperature, the TaN phase was increased over TaC and $Ta_3N_5$ and crystallinity, work function, conductivity and density of the film were increased. Also the oxygen uptake was decreased due to the increase of the film density. With the increase of the TaC phase in $T_aC_xN_y$ film, the work function was decreased to 4.25eV and with the increase of the TaN phase in $T_aC_xN_y$ film,it was increased to 4.48eV.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.451-463
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• 2009

The purpose of this research is to develop thin film materials and fabrication process for efficient $TiO_2$/CdTe solar cells. In this work photocatalyst titanium dioxide was prepared by sol-gel procedure according to reaction condition, the mole ratio of $H_2O$/TTIP, pH of solution and aging condition of powder. The prepared titanium dioxide was thermally treated from 300 to $750^{\circ}C$. Maximum intensity of anatase phase of titanium dioxide was achieved by calcination at $600^{\circ}C$ for 2 hr. And it was mixture of anatase and rutile phase when temperature of calcination was $750^{\circ}C$. It has been known that the properties of synthesized titanium dioxide according to aging time and calcination temperature was converted to anatase phase crystal on increasing of aging time. Also the current density has been increased with aging time and temperature, the efficiency has been increased with because of reason on above results. The formation of chemical bonding on oxygen and cadmium telluride under oxygen circumstances had been observed, and oxygen of thin film surface on cadmium telluride had been decreased with the treatment of chromate and hydrazine. As results had been shown that the energy conversion efficiency of cadmium telluride use by rapidly treatmented heat at the condition of $550^{\circ}C$ under air circumstance got 12.0%, 6.0% values according to $0.07cm^2$, $1.0cm^2$ surface area, respectively.

• Journal of Adhesion and Interface
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• v.8 no.1
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• pp.15-27
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• 2007

Polyimide (PI) surface modification was carried out by ion-beam treatment and silane-imidazole coupling agent to improve the adhesion between polyimide film and copper. Silane-imidazole coupling agent contains imidazole functional groups for the formation of a complex with copper metal through a coordination bonding and methoxy silane groups for the formation of siloxane polymers. The PI film surface was first treated by argon (Ar)/oxygen ($O_2$) ion-beam, followed by dipping it into a modified silane-imidazole coupling agent solution. The results of X-ray photoelectron spectroscopy (XPS) spectra revealed that the $Ar/O_2$ plasma treatment formed oxygen functional groups such as hydroxyl and carbonyl groups on the polyimide film surface and confirmed that the PI surface was modified by a coupling reaction with imidazole-silane coupling agent. Adhesion between copper and the treated PI film by ion-beam and coupling agent was superior to that with untreated PI film. In addition, adhesion of PI film treated by an $Ar/O_2$ plasma to copper was better than that of PI film treated by a coupling agent. The peeled-off layers from the copper-PI film joint were completely different in chemical composition each other. The layer of PI film side showed similar C1s, N1s, O1s spectra to the original Upilex-S and no Si and Cu atoms appeared. On the other hand the layer of copper side showed different C1s and N1s spectra from the original PI film and many Si and Cu atoms appeared. This indicates that the failure occurs at an interface between the imidazole-silane and PI film layers rather than within the PI layers.