• Journal of the Korean Chemical Society
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• v.47 no.3
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• pp.199-205
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• 2003

Complexes of uranyl ion $UO^{+2}_2$with Schiff-bases obtained by condensing glycylglycine with salicylaldehyde; 2-hydroxy-1-naphthaldehyde, 2,3-dihydroxybenzaldehyde, and 2,4-dihydroxybenzaldehyde have been synthesized and characterized through elemental analysis, conductivity measurements, magnetic susceptibility determinations, u.v., i.r. and $^1H$ nmr spectra as well as d.t.a., t.g. and d.s.c. techniques. Structures and mechanisms of thermal decomposition are proposed.

• Journal of Electrical Engineering and information Science
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• v.2 no.3
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• pp.82-87
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• 1997

Ion-Sensitive Field-Effect Transistors(ISFETs) with LPCVD silicon nitride as a sensitive gate were fabricated on the basis of a CMOS process. The silicon nitride was deposited directly on a poly silicon gate-electrode. Using a specially designed measuring cell, the hydrogen ions sensing properties of the ISFET in liquid could be investigated without any bonding or encapsulation. At first, th sensitivity was estimated by simualtions according to the site-binding theory and the experimental results were analysed and compared with simulated results. The measured dta were in good agreement with the simulated results. The silicon nitride based ISFET has good linearity evaluated from correlation factor ($\geq$0.9998) and a mean pH-sensitivity of 56.8mV/pH. The maximum hysteresis width between forward(pH=3\longrightarrowpH=11)- and backward(pH=11\longrightarrowpH=3) titration was 16.7mV at pH=6.54.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.3
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• pp.388-393
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• 2010

In recent years the research has been focused on the preparation of special glasses, i.e., chalcogenide and heavy metal oxide ones that can transmit optical radiation above 2 um and also other optical parameters exceed those of silica based glasses. The attention in this paper is focused on chalcogenide glasses, on preparation of high quality base glass, for an application in infrared optical product design and manufacture. The amorphous materials of As-Se and Ge-As-Se chalcogenides were prepared by a standard melt-quenching technique. The compositions were mesaured by ICP-AES and EPMA, and structural and thermal properties were studied through various annealing processes. Several anomalies of glass transition and crystallization were observed in the DSC/DTA/TG results of the chalcogenide glass.

• Journal of the Korean Ceramic Society
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• v.35 no.10
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• pp.1085-1093
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• 1998

Amorphous alumina powder prepared by the fast calcination of aluminum trihydroxide(Al(OH)3 gibbsite) for 0.5 second at 580$^{\circ}C$ was investigated rehydration propeties. Phase composition crystal size and mor-phology surface area pore volume and pore size distribution of pesudo-boehmite and bayerite crystals changed with temperature time water/alumina ratio and particle size when amorphous alumina rehydrated with water. Phase compositions were examined with XRD and DTA and crystal sized morphologies were investigaed with SEM and TEM. Also rehydration properties of amorphous alumina were in-vestigated by measuring the surface area pore volume and pore size distribution.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.64-66
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• 2004

$Pb(Zr_{0.3},Ti_{0.7})O_3$, $Pb(Zr_{0.3},Ti_{0.3})O_3$ powders were prepared by the sol-gel method and PZT heterolayered thick films were fabricated by the screen-printing method. The structural properties as a faction of the composition ration were studied. As a result of the differential thermal analysis (DTA), exothermic peak was observed at around $864^{\circ}C$ dne to the formation of the polycrystalline perovskite phase. The PZT heterolayered thick film sintered at $1050^{\circ}C$ for 10min showed the average grain size $1{\sim}1.4{\mu}m$. The average thickness of PZT heterolayered thick films, obained by $3{\sim}6times$ of screen-printing, was approximately $60{\sim}110{\mu}m$.

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.417-421
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• 1999

The complex, K3[La(TTHA)]5H,O, was prepared and its crystal structure was analyzed by single crystal X-ray diffraction method. In the complex, the La(Ⅲ) ion adopts a ten-coordinate geometry with four nitrogen atoms and six carboxyl oxygen atoms from the same TTHA ligand molecule. Its coordination polyhedron can be described as a distorted bicapped square antiprism. Each [La(TTHA)]3- anion is linked by K+ cations via carboxyl groups of TTHA ligand to form a three dimensional crystal structure. The thermal properties were investigated by TG and DTA techniques in argon atmosphere. The materials resulting from thermal treatment were La(OH)3 and K2O which were identified by powder X-ray diffraction technique.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1366-1370
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• 2001

Thin films of the SiO2-TiO2-PDMS composite material have been prepared by the sol-gel dip coating method. Acid catalyzed solutions of tetraethoxy silane (TEOS) and polydimethyl siloxane (PDMS) mixed with titanium isopropoxide Ti(OiPr) were used as precursors. The optical and structural properties of the organically modified 70SiO2-30TiO2 composite films have been investigated with Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible Spectroscopy (UV-Vis), Differential Thermal Analysis (DTA) and prism coupling technique. The films coated on the soda-lime-silicate glass exhibit 450-750 nm thickness, 1.56-1.68 refractive index and 88-94% transmittance depending on the experimental parameters such as amount of PDMS, thermal treatment and heating rate. The optical loss of prepared composite film was measured to be about 0.34 dB/cm.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.226-231
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• 2001

The purpose of this paper is to propose the experimental method of thermal properties of Phase Change Materials (PCMs) by using T-history method. As far, in order to measure the heat of fusion and specific heat of PCMs, conventional thermal analysis methods such as DSC and DTA have been used. Because these methods test very small samples, thermal properties of samples are usually different from those of materials consisting of several components. For these reasons, T-history method, the simple measurement method of the heat of fusion and specific heat of PCMs have been performed. In this paper, we investigated the thermal properties of low temperature PCMs(below $0^{\circ}C$) under the charging process by using T-history method. The results are compared to those of DSC method. The T-history method will be useful for selection of the best PCM from lots of candidates and development of new PCMs.

• Journal of Magnetics
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• v.14 no.4
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• pp.161-164
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• 2009

Iron-doped $Sn_{1-x}Fe_xO_2$ (x = 0.0, 0.05, 0.1, 0.2, 0.33) thin films on Si(100) substrates and powders were prepared by a chemical solution process. The x-ray diffraction (XRD) patterns of the $Sn_{1-x}Fe_xO_2$ thin films and powders showed a polycrystalline rutile tetragonal structure. Thermo gravimetric (TG) - differential thermal analysis (DTA) showed the final weight loss above $430{^{\circ}C}$ for all powder samples. According to XRD Rietveld refinement of the powders, the lattice parameters and unit cell volume decreased with increasing Fe content. The magnetic properties were characterized using a vibrating sample magnetometer (VSM) and M$\ddot{o}$ssbauer spectroscopy. The thin film samples with x = 0.1 and 0.2 showed paramagnetic properties but thin films with x = 0.33 exhibited ferromagnetic properties at room temperature. Mossbauer studies revealed the $Fe^{3+}$ valence state in the samples. The ferromagnetism in the samples can be interpreted in terms of the direct ferromagnetic coupling of ferric ions via an electron trapped in a bridging oxygen deficiency, which can be explained using the F-center exchange model.

• Clean Technology
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• v.24 no.1
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• pp.9-14
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• 2018

In this study, Material life cycle evaluation was performed to analyze the environmental impact characteristics of TiN-Zr membrane manufacturing process. The software of MLCA was Gabi. Through this, environmental impact assessment was performed for each process. Transition metal nitrides have been researched extensively because of their properties. Among these, TiN has the most attention. TiN is a ceramic materials which possess the good combination of physical and chemical properties, such as high melting point, high hardness, and relatively low specific gravity, high wear resistance and high corrosion resistance. With these properties, TiN plays an important role in functional materials for application in separation hydrogen from fossil fuel. Precursor TiN was synthesized by sol-gel method and zirconium was coated by ball mill method. The metallurgical, physical and thermodynamic characteristics of the membranes were analyzed by using Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDS), X-ray Diffraction (XRD), Thermo Gravimetry/Differential Thermal Analysis (TG/DTA), Brunauer, Emmett, Teller (BET) and Gas Chromatograph System (GP). As a result of characterization and normalization, environmental impacts were 94% in MAETP (Marine Aquatic Ecotoxicity), 2% FAETP (Freshwater Aquatic Ecotoxicity), 2% HTP (Human Toxicity Potential). TiN fabrication process appears to have a direct or indirect impact on the human body. It is believed that the greatest impact that HTP can have on human is the carcinogenic properties. This shows that electricity use has a great influence on ecosystem impact. TiN-Zr was analyzed in Eco-Indicator '99 (EI99) and CML 2001 methodology.