Single crystal ZnIn2S4 layers were grown on thoroughly etched semi-insulating GaAs(100) substrateat 450oC with hot wall epitaxy (HWE) system by evaporating ZnIn2S4 source at 610oC. The crystalline structureof the single crystal thin films was investigated by the photoluminescence (PL) and double crystal X-ray rockingcurve (DCRC). The temperature dependence of the energy band gap of the ZnIn2S4 obtained from theabsorption spectra was well described by the Varshni’s relation, Eg(T)=2.9514eV-(7.24×10−4eV/K)T2/(T＋489K). After the as-grown ZnIn2S4 single crystal thin films were annealed in Zn-, S-, and In-atmospheres, theorigin of point defects of ZnIn2S4 single crystal thin films has been investigated by the photoluminescence (PL)at 10K. The native defects of VZn, VS, Znint, and Sint obtained by PL measurements were classified as a donorsor acceptors type. And we concluded that the heat-treatment in the S-atmosphere converted ZnIn2S4 singlecrystal thin films to an optical p-type. Also, we confirmed that In in ZnIn2S4/GaAs did not form the nativedefects because In in ZnIn2S4 single crystal thin films existed in the form of stable bonds.

The wetting behavior of molten Fe on α-Al2O3 single crystals with three different crystallographic orientations, R(01ar12), A(11ar20), and C(0001), was investigated using the sessile drop method under a 10%H2-Ar atmosphere at 1873 K. It was found that the differences in the contact angle of the three differently oriented α-Al2O3 single crystals were not significant (within 5˚, which corresponded to the changes in the work of adhesion of 157mJ/m2) due to the surface reconstruction.

The crystal structures and morphologies of precipitates in L10-ordered TiAl intermetallics containing nitrogen were investigated by transmission electron microscopy (TEM). Under aging at an approximate temperature of 1073 K after quenching from 1423 K, TiAl hardens appreciably due to the nitride precipitation. TEM observations revealed that needle-like precipitates, which lie only in one direction parallel to the [001] axis of the L10-TiAl matrix, appear in the matrix preferentially at the dislocations. Selected area electron diffraction (SAED) pattern analyses showed that the needle-shaped precipitate is perovskite-type Ti3AlN (P-phase). The orientation relationship between the P-phase and the L10-TiAl matrix was found to be (001)p//(001)TiAl and [010]p//[010]TiAl. By aging at higher temperatures or for longer periods at 1073 K, plate-like precipitates of Ti2AlN (H-phase) with a hexagonal structure formed on the 111 planes of the L10-TiAl matrix. The orientation relationship between the Ti2AlN and the L10-TiAl matrix is (0001)H//(111)TiAl and H//TiAl.

Thiol-ene 중합이 가능한 새로운 반응성 액정 단량체로서 2,5-bis[4'-(5-hexenyloxy) benzoyloxy]toluene를 합성하였다. 반응성 액정 단량체는 ethyl 4-hydroxybenzoate와 6-bromo-1-hexene을 반응하여 얻은 중간체인 4'-(5-hexenyloxy)benzoic acid와 methyl hydroquinone를 축합하여 79%의 수율로 합성하였다. 얻어진 반응성 액정 단량체의 구조는 1H-NMR과 FT-IR을 이용하여 확인하였으며, DSC와 온도 조절기가 부착된 편광현미경을 이용하여 관찰한 결과 65℃와 157℃ 사이에서 네마틱 액정상을 보임을 확인하였다. 반응성 액정 단량체는 1,6-hexanethiol, 광개시제와 함께 혼합하여 thiol-ene 중합을 위한 광중합 조성물을 제조하였다. 러빙 처리된 폴리이미드 기판 상에서 이와 같은 조성물을 코팅한 후 광조사에 의해 중합한 결과 λ/4의 위상차를 갖는 광학보상 필름을 제조할 수 있었다.

Poly(imide p-alkoxycinnamate)s of various alkyl chain lengths were synthesized by esterifying chloromethylated polyimide (CMPI), a synthetic platform for functionalized polyimides. Soluble CMPI, obtained by chloromethylation of soluble polyimide from diaminodiphenylether and 4,4’-(hexafluoroisopropylidene) diphthalic anhydride, was esterified with various p-alkoxycinnamic acids in the presence of base and phase transfer catalyst. The reaction underwent almost quantitatively. The structure of resulting polymer was characterized by 1H-NMR and FT-IR spectroscopic methods. Thin polymer film on a glass substrate was irradiated with polarized UV light, inducing a homogeneous liquid crystal alignment.

Core loss of soft magnetic powder cores have been focused on to achieve high efficiency of power supplies. In this study the effects of crystal grain size on core loss were investigated by changing heat treatment conditions. It was found that core loss is influenced by crystal grain size because eddy current loss decreased and hysteresis loss increased by making crystal grain size smaller, and it is also influenced by particle size.

We newly designed and manufactured a new arranging system for a three-dimensional artificial crystal of monosized micro particles. In this system, a robotic micro-manipulator accurately locates the spherical particle onto the lattice point, and subsequently fiber lasers micro-weld the contact points between the neighboring particles. Actually, one- and two-dimensional arrays were constructed using monosized tin particles with the diameter of 400 m. Moreover, due to optimization of the process parameters, we successfully constructed the artificial crystals of simple cubic and diamond structures. In particular, the diamond structure which can represent a large photonic band gap is expected to progress toward a practical photonic crystal device.

The effects of reaction temperature and precursor concentration on the microstructure and magnetic properties of nanoparticles synthesized as final products of iron acetylacetonate in chemical vapor condensation (CVC) were investigated. Pure phase was obtained at temperature above and crystallite size of nanoparticles decreased with lowering precursor concentration. Also, the coercivity decreases with decreasing crystallite size of nanopowder. The lowest coercivity was 7.8 Oe, which was obtained from the nanopowder sample synthesized at precursor concentration of 0.3M. Then, the crystallite size of nanoparticles was 8.8 nm.

Three-dimensional artificial crystals with periodicity corresponding to terahertz wave lengths were fabricated by self-assembling monosized metal spherical particles. The metal crystals were weakly sintered to utilize them as templates. The metal templates were inverted to air spheres crystal embedded in dielectric resin though infiltration and etching. The resulting resin inverted crystals clearly presented the photonic stop gaps within terahertz wave region and the frequencies of the gaps were confirmed to agree well with calculation by plane wave expansion method.

[ ](R=Pr, Nd, and Sm) was synthesized and their magnetic properties and charge ordering(CO) transition related with lattice dynamics and oxygen vacancy were systematically investigated. The charge disproportion ation(CD) in (R=Pr,Nd) was in which two kins of iron with valence state and were found with ratio of 2:1. In this charge ordering state a sequence of exists aligned along the [111] direction of the pseudocubic perovskite structure. The charge ordering exist in distorted structure involving hybridization. The disordering phases coexist in distorted structure as temprature in creases that is controlled amount of oxygen vacancy. The magnetic hyperfine fields indicate charge tranfering temperature as it dissapeared drastically.

The structure of nitrogen adsorption complex of fully dehydrated Cd2+ ion exchanged zeolite-X, |Cd46(N)18|[Si100Al92O384], was determined in the cubic space group Fd3 at 21(1) ℃ [a = 24.863(4) ] by single crystal X-ray diffraction analysis. The crystal was prepared by ion exchange in a flowing steam of 0.05 M aqueous solution Cd(NO3)2 : Cd(O2CCH3)2 = 1:1 for five days, followed by dehydration at 500℃ and 2×10-6 Tor. for two days, and exposured to 100 Tor. zeolitically dry nitrogen gas at 21(1) ℃. The structure was determined in atmosphere, and was refined within F0 〉 4Σ(F0) using reflection for which the final error can appear in indices R1 = 0.097 and wR2 = 0.150. In this structure, Cd2+ ions occupied four crystallographic sites. Nine Cd2+ ions filled the octahedral site I at the centers of hexagonal prisms (Cd-O = 2.452(16) a). Eight Cd2+ ions filled site I' (Cd-O = 2.324(19) a). The remaining 29 Cd2+ ions are found at two nonequivalent sites II (in the supercages) with occupancy of 11 and 18 ions. Each of these Cd2+ ions coordinated to three framework oxygens, either at 2.159(15) or 2.147(14) a, respectively. Eighteen nitrogen molecules were adsorbed per unit cell and three per supercage.

Aluminum matrix composites strengthened by the quasi-crystalline (QC) phase were developed in the present study. The icosahedral phase was produced by gravity casting and subsequent heat treatment. The mechanical milling process was utilized in order to produce the Al/QC composite powders. The microstructures of the composite powders were examined by optical microscopy (OM) and scanning electron microscopy (SEM). The composite powders were subsequently canned, degassed and extruded in order to produce the bulk composite extrusions with various volume fractions of QC. The microstructure and mechanical properties of the extrusions were examined by OM, SEM, Vickers hardness tests and compression tests. It was found that the microstructures of the Al/QC composites were uniform and the mechanical properties could be significantly improved by the addition of the QC phase.

The structure of a carbon monoxide sorption complex of dehydrated fully Ca2+-exchanged zeolite X, |Ca46(CO)27|[Si100Al92O384]-FAU, has been determined in the cubic space group Fd 3 at 21℃ (a = 24.970(4) ) by single-crystal X-ray diffraction techniques. The crystal was prepared by ion exchange in a flowing stream of 0.05 M aqueous Ca(NO3)2 for three days, followed by dehydration at 400℃ and 2×10-6 Torr for two days, and exposure to 100 Torr of zeolitically dry carbon monoxide gas at 21℃. The structure was determined in this atmosphere and was refined, using the 356 reflections for which Fo 〉 4Σ(Fo), to the final error indices R1 = 0.059 and wR2 = 0.087. In this structure, Ca2+ ions occupy three crystallographic sites. Sixteen Ca2+ ions fill the octahedral site I at the centers of hexagonal prisms (Ca-O = 2.415(7) a). The remaining 30 Ca2+ ions are found at two nonequivalent sites II (in the supercages) with occupancies of 3 and 27 ions. Each of these Ca2+ ions coordinates to three framework oxygens, either at 2.276(10) or 2.298(8) a, respectively. Twenty-seven carbon monoxide molecules have been sorbed per unit cell, three per supercage. Each coordinates to one of the latter 16 site-II Ca2+ ions: C-Ca = 2.72(8) a. The imprecisely determined N-C bond length, 1.26(14) a, differs insignificantly from that in carbon monoxide(g), 1.13 a.

Liquid crystal (LC) system was introduced into W/O emulsion in order to enhance the stability and moisturizing effect. The LC system, composed of beeswax, surfactant, and water was formed on the surface of emulsion droplet, which was investigated through a polarized microscope. The phenomenon that the viscosity in W/O emulsion system is decreased with time, was reduced by the formation of LC with the addition of beeswax. Centrifugal separation test showed that the stability of emulsion system was increased with the addition of beeswax to 3%. The color change of vitamin C was delayed in LC emulsion systems, which indicates stabilization effect against the oxidation of vitamin C. Evaporation rate in W/O emulsion was retarded by LC, so that high moisturizing effect is expected in W/O LC system.