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We provide the material synthesis method, crystal structure information, and characterization of a novel mixed-valent metal oxide KIn0.33IIITe0.67VITe2IVO7, closely related to zirconolite (CaZrTi2O7), a radioactive waste immobilized material, having a 3D framework. The reported metal oxide containing an alkali-metal cation (K+), main-group cation (In3+), tellurate, and tellurite has been synthesized as both single crystals and a pure polycrystalline phase through a hydrothermal synthesis method. Single-crystal X-ray diffraction indicates that KIn0.33Te2.67O7 crystallizing in the orthorhombic space group Cmcm (No. 63) reveals a 3D framework structure with a 1D channel consisting of Te/InO6 octahedra and TeO4 polyhedra. An interesting transition reaction from KIn0.33Te2.67O7 to KIn(TeO3)2 under hydrothermal conditions at 230 °C is discussed.

Fluorescent nanodiamonds (FNDs) contain nitrogen vacancy (NV) centers that emit photostable fluorescence in the wavelength range between 500 and 800 nm, which does not overlap with cellular autoflu...

For ensuring nuclear safeguards, we report the analytical signal-detection performance of thermal ionization mass spectrometry (TIMS) with continuous heating for the measurement of isotopic ratios in samples containing ultra-trace amounts of uranium. As methods for detecting uranium signals, peak-jumping mode using a single detector and static mode using multiple detectors were examined with U100 (10% 235U-enriched) uranium standard samples in the femtogram-to-picogram range. Uranium isotope ratios, n(235U)/n(238U), were measured down to levels of 1 fg and 3 fg in static and peak-jumping modes, respectively, while n(234U)/n(238U) and n(236U)/n(238U) values were measured down to levels of 100 fg in both modes. In addition, the dependency of the 238U signal intensity on sample quantity exhibited similar tendencies in both modes. The precisions of the isotope ratios obtained in the static mode over all sample ranges used in this study were overall slightly higher than those obtained in peak-jumping mode. These results indicate that isotope ratio measurements by TIMS with continuous heating are almost independent of the detection method, i.e., peak-jumping mode or static mode, which is characteristic of isotope-ratio measurements using the TIMS method with continuous heating. TIMS with continuous heating is advantageous as it exhibits the properties of multiple detectors within a single detector, and is expected to be used in various fields in addition to ensuring nuclear safeguards.

Crystallographic properties of Zr and ZIRLO™ in the temperature range of 30–1430 °C were investigated using in situ high-temperature X-ray diffraction (HT-XRD). Hexagonal Zr diffraction peaks observed at 30 °C started to vanish above 1110 °C for Zr and 1230 °C for ZIRLO™ owing to oxidation, resulting in a composition with monoclinic ZrO2, tetragonal ZrO2, and rhombohedral Zr3O. Furthermore, based on Pawley refinement of in situ HT-XRD spectra, we demonstrated that the lattice thermal expansion in ZIRLO™ occurred in a stable manner compared to that in Zr, which contribute to the enhancement of its mechanical properties via thermal treatment.

In this study, we report a new method for fabricating nanoporous thin films. In the first step, metal–carbon thin films were prepared by radio-frequency reactive magnetron sputtering, using Cu, Ni, and Ti targets as the metal sources and CH4 gas as the carbon source during the co-deposition process. In the second step, the metal–carbon films were then oxidized by an oxygen plasma generated with a flowing a gas mixture of Ar and O2, and nanoporous metal–oxide films were obtained by removing carbon atoms from the metal–carbon thin films. The pores in the films varied with the amount of carbon in the film surface, and mesopores grew to lager macropores as the flow rate of CH4 was increased. Depending on the film composition, the calculated porosity varied from 50% to 90%. With advantages such as a wide range of suitable raw materials and good reproducibility, this fabrication method is expected to offer a new approach to the commercial production of nanoporous materials.

In this study, a method of forming highly adhesive bioactive Ti–Mg alloy thin film on a polyether ether ketone (PEEK) was investigated. To increase the adhesion strength, a PEEK surface was sanded with SiC paper and Ti–Mg ions were implanted by plasma immersion ion implantation & deposition (PIII&D), prior to Ti–Mg alloy thin film deposition. Then, these samples were immersed in the simulated body fluid (SBF) solution for seven days to ensure that hydroxyapatite was formed. In a separate experimental procedure, the thin films were immersed in a physiological saline solution for seven days to check the morphology after magnesium was dissolved. The results show that the adhesion strength increased to 36.14 MPa, and crystallization of hydroxyapatite was most pronounced in the composition of Ti–Mg 85/15 at%. These findings demonstrate that PIII&D is a promising surface treatment tool for PEEK implants.

The coverage and temperature dependence of ZIRLO cladding with H2O adsorption are studied using synchrotron-based high-resolution photoemission spectroscopy (HRPES). Based on the analytical results of the Zr 3d, O 1 s, C 1 s, and Sn 3d HRPES profiles prior to H2O adsorption, we determine the surface compositions of O2−, hydroxyl OH−, chemisorbed H2O, zirconium carbide, adventitious carbon, Sn metal, and SnO2 in ZIRLO. When ZIRLO is exposed to H2O molecules, the relative proportion of zirconium metal decreases, whereas that of the total zirconium oxides increases, suggesting the reaction between H2O and the zirconium metal in ZIRLO. On annealing a sample with 1000 L H2O on ZIRLO at 300 °C, Zr2O3 and ZrO2 decompose, and oxygen diffuses into the bulk, thereby reducing the oxidation states of zirconium on the surface. Moreover, at this temperature, the excess H2O molecules on ZIRLO are thoroughly desorbed and tin element is diffused into the bulk in ZIRLO.

The mono- and di-chloroform solvates of [Au2 (μ-1,2-bis(diphenylarsino)ethane)2 ](AsF6 )2 undergo single-crystal-to-single-crystal transformations that result in gain (over 12 hours) or slow loss (over five years) of only one chloroform molecule. The change in solvation results in changes in the structure and luminescence of the digold cation. The cation consists of a pair of slightly bent As-Au-As units that are connected through the two bridging dpae ligands and by aurophilic interactions with Au⋅⋅⋅Au contacts of 3.05152(15) A in the disolvate or 2.9570(5) A in the monosolvate.

UO2 pellets doped with 1, 5 and 10 mol% Th before and after oxidation were analyzed by using Raman spectroscopy to investigate the Th doping effect on the structural changes during oxidation of UO2. While the Raman spectra of all sample pellets showed a close-to-perfect fluorite structure before oxidation, those of oxidized (U1−yTh y )O2+x (0.03 ≤ x ≤ 0.06) pellets showed distinct defect structures after oxidation at 1150 °C with CO/CO2 = 0.001. The increasing relative ratio of first-order longitudinal optical modes of (U1−yTh y )O2+x with increasing doping levels should represent the defect structure due to the Th doping effect.

Isobaric interference is a major limitation of secondary ion mass spectrometry. We developed a simple correction method for polyatomic mass interferences from lead in isotope ratio measurements of uranium. Lead-generated isobars were measured to determine their formation rates relative to lead isotopes. The rates were used to mathematically subtract the isobar contributions from the signal intensities in the uranium mass range. The correction method was successfully verified using mixed uranium-lead samples (oxide powder and solution-dried residue).

Isotopic analyses of plutonium and low-enriched uranium mixtures with particle sizes of 0.6–3.3 μm were performed using thermal ionization mass spectrometry with a continuous heating method to verify its effectiveness for the accurate analysis of minor isotopes without sample pretreatment. The mixed particles used in this study were prepared from a mixed solution of plutonium (SRM 947) and uranium (U010, 235U 1% enriched) reference materials. The isotope ratios for plutonium in the individual mixed particles, including 238Pu/239Pu, 241Pu/239Pu as well as 240Pu/239Pu, and 242Pu/239Pu, were in good agreement with the certified values despite the isobaric interference of 238U and 241Am. The isotope ratios for uranium in the mixed particles also agreed well with the certified values within the range of error. However, the isotope ratios for minor isotopes, such as 234U and 236U, in the particles with diameters of less than approximately 1.8 μm could not be measured because numbers of 234U and 236U atoms in analyzed particles are too low. These results indicate that thermal ionization mass spectrometry with a continuous heating method is applicable for the analysis of trace amounts of plutonium isotopes, including 238Pu and 241Pu, despite the presence of the respective isobars 238U and 241Am in the microsamples.

This study explored the crystallographic characterization of zirconium, zirconium-based samples containing minor alloying elements, simulated Zircaloy-4, and simulated ZIRLO at a temperature range of 30–870 °C using in situ high-temperature X-ray diffraction. The results from Pawley refinement demonstrated that the lattice thermal expansion along the a-axis direction is suppressed by the tin element, in contrast to the other minor alloying elements. Moreover, the simulated ZIRLO possesses the enhanced resistance for lattice thermal expansion compared to the simulated Zircaloy-4, indicating that a ZIRLO cladding has a better performance in suppressing the change in the lattice constants under a thermal environment.

Multi-channel inductively coupled plasma mass spectrometry and multi-collector ICPMS were used for effective bulk analysis techniques of environmental samples with high thorium contents. A desolvating nebulizer system was adopted to reduce the 232ThH/232Th formation rate, which was evaluated using U/Th mixture solution. A UTEVA-based chemical separation method, with adjustment of the separation parameters for uranium and thorium, allowed for effective separation of uranium. The separation yields for uranium and thorium were estimated from the elution profiles of various U/Th mixture solutions. Bulk analysis of uranium in simulated samples with high thorium contents was performed to validate the improved analytical procedures.

Novel mixed-valent titanium tellurium oxides, Ti1-xTexTe3O8+x (compound A, B, and C for x ​= ​0, 0.1, and 0.12) were synthesized from TiOSO4·xH2SO4·xH2O, TeO2, and H3BO3 using hydrothermal reaction conditions. The crystal structures of the materials were confirmed and refined using single-crystal X-ray diffraction. The compounds have three-dimensional framework structures consisting of TiO6 or Ti/TeO6 octahedra and asymmetric TeO4 polyhedral groups. The cell parameter of compound A, B, and C increased with the increase in the Ti – O bond distance in the TiO6 octahedron and is attributed to the increase in the Te6+ cation doping level. Detailed characterizations of the prepared materials, including Infrared, UV–visible diffuse reflectance, Raman spectra, thermogravimetric analyses, out-of-center distortion, and dipole moment calculations were performed.

We report a facile synthesis method for the preparation of transfer-free graphene on dielectric substrates from co-deposited nickel–carbon (Ni–C) films. To fabricate 75-nm-thick Ni–C layers on top of dielectric substrates, DC reactive magnetron sputtering was performed at a gas pressure of 2 mTorr by flowing a gas mixture of argon (Ar; flow rate: 5 sccm) and methane (CH 4 ; flow rate: 1 sccm), while 200 W DC input power was applied to a Ni target. Then, the sample was annealed at 1000 °C for 4 min at a pressure of 1 Torr and Ar flow rate of 200 sccm. The Ni–C layer was removed by a 0.5 M FeCl 3 aqueous solution, and graphene was directly obtained on the dielectric substrate without any additional transfer process. The graphene quality was significantly influenced by annealing conditions, CH 4 flow rate during co-deposition, and Ni–C thin film thickness. Furthermore, temperature modulation was conducted to decrease the graphene sheet defect coverage down to 7.2%. Sheet resistance and transmittance (550 nm) of the transfer-free graphene obtained under optimal conditions were 1.9 kΩ sq −1 and 93.9%, respectively. This facile non-transfer process will facilitate future research on graphene as well as its industrial applications.

This paper describes an alternative approach to nuclear forensic analysis by employing time-of-flight (TOF) SIMS and sector-field (SF) SIMS collaboratively. A set of synthetic samples consisting of UO2 and other metal (Gd, Mo or Zr) oxide was analyzed by the both instruments. With TOF–SIMS, qualitative elemental analysis was possible in U-dominant or low-U samples. TOF–SIMS was also useful for investigating potential isobars for U isotopes induced by the other metals. To avoid the isobaric interferences, particle search and major U isotope analysis using SF–SIMS were performed by measuring UO2 + instead of U+, and thus the effects of interference were reduced.

The perpendicular magnetic anisotropy (PMA) properties of Pt/Co/MgO trilayers are investigated as a function of the MgO sputtering power (PMgO) and its thickness (tMgO), both of which are important parameters affecting the degree of oxygen interpenetration into Co during sputtering. A strong PMA is achieved at small values of PMgO and tMgO, where the oxygen interpenetration into Co is expected to be small. The range of oxygen interpenetration is relatively extended in such a way that it affects both the Pt/Co and Co/MgO interfaces. The PMA properties of as-deposited samples are improved by post-annealing for temperatures up to 400 °C examined in this study, probably due to the diffusion of the interpenetrated oxygen atoms toward the Co/MgO interface. In a structure of Pt/Co (0.6 nm)/MgO (2 nm), which is fabricated at PMgO = 50 W and then annealed at 400 °C, a huge saturation field is achieved (over 40 kOe) indicating a very strong PMA. Between the two interfaces of Pt/Co and Co/MgO, the PMA is mainly due to the former in the as-deposited state, but the contribution of the latter increases with the increase in the annealing temperature.

Suitable analytical procedures for the bulk analysis of ultra-trace amounts of uranium and plutonium have been developed using multi-collector inductively coupled mass spectrometry (MC.ICP.MS). The quantification and determination of the isotopic ratios of uranium and plutonium in three simulated swipe samples, a swipe blank, and a process blank were performed to validate the analytical performance. The analytical results for the simulated swipe samples were in good agreement with the certified values, based on the measurement quality goals for the analysis of bulk environmental samples recommended by the International Atomic Energy Agency (IAEA)

Improved bulk analysis based on extraction chromatography and systematic evaluations of uncertainties of plutonium isotopes at ultra-trace levels in environmental swipe samples are presented. In the modified method based on a single column system using UTEVA resin for MC-ICP-MS, hydrogen peroxide was introduced to obtain pure plutonium isotopes from chemical separation by removing excess organic-based reducing reagents. We confirmed that hydrogen peroxide effectively decomposed the reducing reagents characterized by UV–Vis absorption spectroscopy and the peak fluctuations were significantly reduced. To examine the reliability of analytical performance, we systematically evaluated the combined uncertainties during the overall chemical procedures using simulated samples containing Pu reference materials.

The development of analytical methods for environmental samples in Korea Atomic Energy Research Institute (KAERI) is discussed. An analysis scheme for environmental samples has been established with an MC-ICP-MS based bulk analysis with adopting UTEVA resin for chemical separation and a particle analysis using FT-TIMS and SIMS. A clean laboratory facility called CLASS (class 100~ class 1000) was also established in order to prevent any cross contamination of the samples. The amount of U and Pu in the process blank sample prepared in the CLASS facility was estimated as 20 pg and less than 0.005 pg, respectively. The control chart of the analytical performance for the uranium standard sample of 100 ppt (NBL U030) indicated that the analytical performance of KAERI in CLASS is within 5 % of the certified values.

A series of isostructural cobalt hydroxychloride salts with the formula Co(OH)Cl were fabricated by using a precipitation method from aqueous solutions of CoCl and NaOH with different mixing ratios. The crystal structure was resolved from neutron powder diffraction data, including the location of H atoms of the hydroxide groups. The structure (space group R3m) consists of an open network of edge-sharing CoO and CoOCl octahedra, forming intercrossed 1D channels where the hydrogen atoms reside. Unusually high values of the magnetic entropy change were observed for all samples, probably due to the geometrically frustrated magnetic structure; for example, the magnetic entropy change was 8.3 J/kg K for the sample with Co/Cl > 2.5 at 10 K in a magnetic field change of 20 kOe., This work was supported by the Converging Research Center Program through the Ministry of Science, ICT and Future Planning, Korea (201505411), and the Basic Science Research Program through the National Research Foundation (NRF) funded by the Ministry of Education (2015063125). J. A. A. acknowledges the Spanish Ministry of Economy and Competitivity by funding the Project MAT2013‐41099‐R.

The individual strengths of perpendicular magnetic anisotropy (PMA) at the bottom and top interfaces in sputtered [Pt/Co/Pt] trilayers are determined. The PMA strength from the top Co/Pt interface is significantly weaker than that from the bottom Pt/Co interface, indicating a similar difference in the interface quality. The contribution to the total anisotropy strength from the top Co/Pt interface increases with decreasing top Pt layer thickness; for a stack of Co thickness 1 nm, the contribution is only 10% for a top Pt layer of thickness 3.0 nm, but it increases to 32% for a Pt layer of thickness 0.2 nm.

The solid state interconversions of four different crystalline compounds containing the Au2(dppe)2I2 unit (dppe is bis-(diphenylphosphino)ethane) have been observed and characterized through X-ray diffraction and emission spectroscopy. Treatment of AuI in acetone with solid dppe yields the crystalline polymorphs: α-Au2(μ-dppe)2I2·2OCMe2 (1) with orange emission and β-Au2(μ-dppe)2I2·2OCMe2 (2) with green emission. Both polymorphs contain dimeric molecules with three-coordinate gold(I) centers that are further apart in the orange emitting (1) (Au⋯Au distance, 3.6720(2) A) than in the green emitting (2) (Au⋯Au distance, 3.3955(2) A). The acetone molecules do not bond to the gold centers in either polymorph. Crystals of α-Au2(μ-dppe)2I2·2OCMe2 (1) and β-Au2(μ-dppe)2I2·2OCMe2 (2) undergo reversible, single-crystal to single-crystal transformations. Exposure of (2) to acetone vapor converts it into (1), while (1) is converted into (2) by exposure to air for a short time. Upon loss of acetone, α-Au2(μ-dppe)2I2·2OCMe2 (1) and β-Au2(μ-dppe)2I2·2OCMe2 (2) are converted into a microcrystalline powder (3) with a green emission. Remarkably, exposure of (3) to acetone vapor converts it into acetone-free Au2(μ-dppe)2(μ-I)2 (4), which displays orange emission. The X-ray crystal structure of Au2(μ-dppe)2(μ-I)2 (4) shows that each gold is in a highly distorted tetrahedral environment with bonds to two phosphorus and two iodine atoms. The transformations between these four types of crystals are notable because of the unusual role of vapors in promoting structural changes within solids that do not necessarily change composition. Thus, the reversible interconversion of α-Au2(μ-dppe)2I2·2OCMe2 (1) and β-Au2(μ-dppe)2I2·2OCMe2 (2) occurs as vapor-stimulated single-crystal-to-single-crystal transformation between polymorphs. Likewise, the irreversible transformation of microcrystalline (3) into Au2(μ-dppe)2(μ-I)2 (4) appears to be another case of a transformation of one polymorph into another.

The remarkable, vapor-induced transformation of the yellow polymorphs of [(C(6)H(11)NC)(2)Au(I)](AsF(6)) and [(C(6)H(11)NC)(2)Au(I)](PF(6)) into the colorless forms are reported along with related studies of the crystallization of these polymorphs. Although the interconversion of these polymorphs is produced by vapor exposure, molecules of the vapor are not incorporated into the crystals. Thus, our observations may have broad implications regarding the formation and persistence of other crystal polymorphs where issues of stability and reproducibility of formation exist. Crystallographic studies show that the colorless polymorphs, which display blue luminescence, are isostructural and consist of linear chains of gold(I) cations that self-associate through aurophilic interactions. Significantly, the yellow polymorph of [(C(6)H(11)NC)(2)Au(I)](AsF(6)) is not isostructural with the yellow polymorph of [(C(6)H(11)NC)(2)Au(I)](PF(6)). Both yellow polymorphs exhibit green emission and have the gold cations arranged into somewhat bent chains with significantly closer Au···Au separations than are seen in the colorless counterparts. Luminescence differences in these polymorphs clearly enhance the ability to detect and monitor their phase stability.

Background: Hydrogen sulfide (H2S) produces a protective effect against myocardial ischemia and reperfusion injury. Sevoflurane, which is used for anesthesia in cardiac problem patients, also has a protective effect. This study is designed to reveal the effects of H 2S under sevoflurane using rat hearts. Methods: The hearts were Langendorff-perfused, subjected to 30 minutes ischemia and 60 minutes reperfusion. Group I was a control group. The other groups were pretreated for 15 minutes before ischemia as follows: 1.6% sevoflurane for group S; 18.5 μM H 2S S for group H; and 1.6 % sevoflurane and 18.5 μM H 2S simultaneously for group HS. Hemodynamics and the infarct size were measured. Results: Group HS presented depressed hemodynamics during pretreatment. LV function in group HS achieved better recovery than group I after reperfusion. The infarct size of groups S, H and HS was smaller than group I, while there were no differences between groups S, H and HS. Conclusions: Exogenous H2S did not enhance the preconditioning effects of sevoflurane. Rather, the results suggest that H2S under sevoflurane might depress hemodynamics. (Korean J Anesthesiol 2012; 62: 461-467)

Solutions containing the components Au(+), dppe (dppe is bis(diphenylphosphino)ethane), and Br(-) in a 1:1:1 ratio can produce three different types of crystals: type A, orange luminescent solvates of the dimer Au(2)(dppe)(2)Br(2) (Au(2)(μ-dppe)(2)Br(2)·2(OSMe(2)), Au(2)(μ-dppe)(2)Br(2)·2(OCMe(2)), Au(2)(μ-dppe)(2)Br(2)·2(CH(2)Cl(2)), Au(2)(μ-dppe)(2)Br(2)·2(HC(O)NMe(2))); type B, green luminescent solvates of the same dimer (Au(2)(μ-dppe)(2)Br(2)·(NCMe) and Au(2)(μ-dppe)(2)Br(2)·0.5(C(4)H(10)O)); and type C, orange luminescent solvates of a polymer ({Au(μ-dppe)Br}(n)·0.5(C(4)H(10)O) and {Au(μ-dppe)Br}(n)·(CH(2)Cl(2))). Some crystals of types A are solvoluminescent. Exposure of type A crystals of Au(2)(μ-dppe)(2)Br(2)·2(OCMe(2)) or Au(2)(μ-dppe)(2)Br(2)·2(CH(2)Cl(2)) to air or vacuum results in the loss of the orange luminescence and the formation of new green luminescent crystals. Subsequent exposure of these crystals to acetone or dichloromethane vapor results in the reformation of crystals of type A. The dimeric complexes in crystals of types A and B are all centrosymmetric and share a common ring conformation. Within these dimers, the coordination geometry of each gold center is planar with a P(2)Br donor set. In other respects, the Au(2)(μ-dppe)(2)Br(2) molecule is remarkably flexible and behaves as a molecular accordion, whose dimensions depend upon the solvate content of a particular crystalline phase. In particular, the dimer Au(2)(μ-dppe)(2)Br(2) is able to accommodate Au···Au separations that range from 3.8479(3) to 3.0943(2) Å, and these variations along with alterations in the Au-Br distances and in the P-Au-P angles are the likely causes of the differences in the luminescence properties of these crystals.

The use of a cooling fan in an induction cooker raises a reliability issue due to the attraction of dust causing a malfunction of the cooling fan and also increases the noise level and power consumption of the device. The purpose of this study is to attempt to solve these problems by molding the Cu coil of an induction cooker with polymer composites that have a low electrical conductivity but a high thermal conductivity. Among the several polymer composites tested in this study, an aluminum nitride-based composite showed the best performance. The results show that the new induction cooker with the molded composite can operate for an extended period of time without the use of a cooling fan. A further advantage of this new type of induction cooker is that the temperature of the substance in the cooking pot increases more rapidly, indicating an increased efficiency of the induction cooker.

The TiN-coated metal-on-polymer hip prosthetic pair has the potential to reduce wear debris of UHMWPE (ultra-high molecular weight polyethylene) and to prevent metallic-ion-induced cytotoxicity. However, high quality and adherent film is a key to the clinical success of hip prostheses. In this study, titanium nitride (TiN) films were deposited on stainless steel using plasma immersion ion implantation & deposition (PIII&D) technique to create high-quality film and an adherent interface. The chemical state and composition were analyzed by X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and energy dispersive spectroscopy (EDS). The mechanical properties of the films were characterized using a micro-hardness tester and a pin-on-disk wear tester, and an x-ray diffractometer (XRD) was used for a crystallographic analysis. The PIII&D-treated TiN films showed a stoichiometric and (200) preferred orientation and micro-hardness up to 150 % higher than untreated film. A TiN-coated specimen using the PIII&D process also showed less UHMWPE wear compared to untreated specimens. The volumetric wear rate of UHMWPE could be reduced by as much as 42 % compared to when Co-Cr alloy was used. The results of this study show that advanced TiN-coating via the PIII&D process is a viable means of reducing UHMWPE wear in the metal-on-polymer bearing couple.

Coenzyme $Q_{10}$ 과 그 유도체 coenzyme $Q_n$ 6종을 합성하고, 이들 유도체에 대하여 상피세포(LLC-PK1 cell)를 이용한 항산화 효과와 NIH/3T3 세포를 이용한 세포독성 실험을 실시하였다. 그 결과, 합성한 coenzyme $Q_n$ 유도체들이 coenzyme $Q_{10}$ 에 비해 우수한 항산화 효과를 나타내었으며, 그 중 coenzyme $Q_3$ -C가 모든 농도에서 $107.7{\sim}135.9%$ 로 가장 우수한 효과를 나타내었다. 또한, 모든 coenzyme $Q_n$ 유도체들이 Coenzyme $Q_{10}$ 과 유사한 세포독성을 나타내었다. Coenzyme $Q_n$ 의 n수에 따른 항산화 효과 및 세포독성 실험에서 isoprene unit의 수가 적은 유도체들에서 우수한 효과를 나타내었다. 【Coenzyme $Q_{10}$ and six derivatives of coenzyme $Q_n$ were synthesized and tested for their antioxidative effects occurred in proximal tubular epithelial cell (LLC-PK1 cell) and cytotoxicities using in NIH/3T3 cell. As the result, synthetic coenzyme $Q_n$ derivatives showed a potent antioxidative effect compared to coenzyme $Q_{10}$ . Among these synthetic compounds, coenzyme $Q_3$ -C at ranged 0.04 to 0.4 mmol showed the $107.7{\sim}135.9%$ of cell viability in LLC-PK1 cell. In the test of NIH/3T3, all synthesized coenzyme $Q_n$ derivatives showed the similar effect compared with coenzyme $Q_{10}$ . A correlation between isoprene unit number of coenzyme $Q_n$ derivatives and its biological effects, we suggest reduction of isoprene unit number of $Q_n$ derivatives may be related to the increase of antioxidants effects and the reduction of cytotoxicities.】

The vaccum-ultra-violet (VUV)- and UV-excited luminescent properties of MgGa 2 O 4 :Mn 2+ phosphor with various co-dopants were investigated. Spinel-structured manganese-activated magnesium gallate exhibited intense green emission with the spectrum centered at 503 nm under 147 and 254 nm excitation induced by the transition from the lowest excited state to the ground state, 4 T 1 – 6 A 1 , of the tetrahedral-sited Mn 2+ . With optimized incorporation ranges, Eu 3+ , Ce 3+ and Al 3+ co-doping, enhanced the overall fluorescence efficiency under 147 nm and these could be tentatively interpreted in terms of optical properties of host compounds and co-doped ions.

Magnetic phases of a Ge48.2Fe51.8 (in atomic%) thin film, fabricated by thermal co-evaporation onto an oxidized Si substrate, are analyzed by Mossbauer spectroscopy as well as magnetometry. Magnetic measurements indicate a superparamagnetic behavior due to the formation of Fe precipitates in an amorphous matrix with an average blocking temperature of 160 K and a spin glass behavior with a spin freezing temperature of 30 K. The superparamagnetic behavior is confirmed from the Mossbauer spectra taken at room temperature. The isomer-shift values indicate that the Fe atom in the amorphous phase is in the high-spin Fe3+ charge state. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Polymer-bonded composites of an Fe–Co based alloy were developed and their magnetostrictive and mechanical properties were characterized. In this work, the static and dynamic magnetostrictive properties as a function of volume fraction of Fe36Co62Ge2 alloy and frequency are characterized. WC powders are especially added to the composites in order to provide increased mechanical properties and extend the high frequency application range. The experimental results for magnetostriction and Young's modulus are in good agreement with those estimated from a uniform strain model. A large Young's modulus of 93.6 GPa and compressive strength of 195 MPa are obtained for the composites with a WC content of 24.5 wt.%. The increase of resonance frequency (fr) as high as 45 kHz is expected from the results of E33. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The effects of the various parameters such as saturation magnetization, anisotropy field, film thickness and resistivity of soft magnetic thin films on the permeability spectra are investigated by using the Landau-Lifshitz-Gilbert equation. Both effects of eddy current loss and ferromagnetic resonance loss on the intrinsic permeability are taken into account to obtain the expression for the effective relative permeability. The calculated permeability spectra are in good agreement with experimental results for nano granular Co-Fe-Al-O thin films, even though only one fitting parameter, the damping constant, is used.

We measure the magnetic and magneto-mechanical properties of polymer-bonded Co ferrites to analyze their behavior as stress sensors in a wide temperature and compressive stress range. The composites, possessing a magnetostriction of 30 10 6 and a Young’s modulus of 50 GPa, are good candidates for a range of sensing applications, with good chemical stability and good high frequency characteristics. r 2002 Elsevier Science B.V. All rights reserved.

1,3,5-Tris(4-phosphonophenyl)benzene was synthesized via a microwave heating assisted route and was subsequently used for the preparation of a new zirconium phosphonate with honeycomb-like structure displaying remarkable thermal stability and hydrolysis resistance.

Polymer-bonded Terfenol-D composites are fabricated using powders with varying sizes and also under various production conditions, in an effort to produce Terfenol-D bulks with good magnetostrictive properties through the optimization of the many fabrication parameters. A large magnetostriction of 536 ppm at 1.1 kOe, combined with a high d max 33 (the maximum slope in the magnetostriction–applied magnetic field curve) of 1.3 ppm/Oe (16.3 nm/A) is obtained for the composite fabricated at the following conditions; the average particle size of 137.5 μm, a phenol content of 3.1 wt%, and a compaction pressure of 0.5 GPa. The magnetostrictive properties achieved in this work are much better than the previously reported results for similar Terfenol-D composites.

Polymer-bonded magnetostrictive composites of flake-type Fe-Co-Ge powder were fabricated and their complex permeability were characterized in the frequency range of 100-100 kHz using the modified ferrite core method. This alternating current (ac) permeability measurement method is firstly proposed in this study, and has some merits, such as easy handling and stress-free measuring. The WC powder, as a highly elastic material, with various amount of 0 wt%-30 wt% was added to form magnetostrictive composite to investigate high-frequency magnetic properties with measured permeability. The real part of permeability is almost constant with frequency varying. Also, the imaginary part of permeability increases exponentially with frequency increase. Both real and imaginary parts of permeability decrease with WC content increase to 20 wt%, but the composite of 30 wt% WC has larger permeability than that of 20 wt%.

An array of coordination-driven supramolecular metal-ligand clusters has been synthesized using polytopic phosphine ligands and coinage metals (Cu(+), Ag(+), Au(+)). Rigid 3-fold or 2-fold symmetric phosphine ligands have been prepared: 1,3,5-tris((4-(diphenylphosphino)ethynyl)phenyl)benzene) (tppepb, L(1)), 1,4-bis((diphenylphosphino)ethynyl)benzene (1,4-dppeb, L(2)), 1,3-bis((diphenylphosphino)ethynyl)benzene (1,3-dppeb, L(3)), 2,6-bis((diphenylphosphino)ethynyl)pyridine (2,6-dppep, L(4)), and 1,5-bis((diphenylphosphino)ethynyl)naphthalene (1,5-dppen, L(5)). Self-assembly of these ligands with coinage metals produces four different types of metal-ligand clusters, or in some cases coordination polymers, depending on number and relative geometry of the phosphine donor atoms. Supramolecular tetrahedral clusters of the formula M4(L(1))4I4 (M = Cu(+), Ag(+), Au(+)) were obtained with the tppepb ligand, encapsulating solvent molecules (either CH2Cl2 or DMF) as guests within the central cavity of the clusters. The ligands 1,3-dppeb (L(3)) and 2,6-dppep (L(4)) give achiral, triple-stranded, dinuclear mesocates with the formula M2(L)3I2 (M = Cu(+) or Au(+)). In contrast, the ligand 1,4-dppeb (L(2)) generates a triple-stranded, dinuclear helicate with Cu(+), but a coordination polymer with Au(+) (both with the empirical formula M2(L(2))3I2). Finally, coordination polymers were obtained from 1,5-dppen (L(5)) with Cu(+). The clusters have been fully characterized by single crystal X-ray crystallography, high-resolution mass spectrometry, (1)H NMR, and (31)P NMR.

Four crystalline dimers of the type, Au(I)(2)(μ-PnP)(2)I(2), where PnP is PPh(2)(CH(2))(n)PPh(2) with n = 3, 4, 5, and 6 have been prepared and characterized by single-crystal X-ray diffraction and by (31)P NMR and infrared spectroscopy. Au(I)(2)(μ-P3P)(2)I(2) and Au(I)(2)(μ-P6P)(2)I(2) are centrosymmetric dimers with the planar Au(I)P(2)I units oriented in antiparallel fashion. Remarkably, noncentrosymmetric Au(I)(2)(μ-P5P)(2)I(2) has its planar Au(I)P(2)I units oriented in parallel manner. Au(I)(2)(μ-P4P)(2)(μ-I)(2) is unique, since it contains four-coordinate gold centers that are bridged by both iodide and diphosphine ligands. All four compounds are luminescent as solids at room temperature. B3LYP, B2PLYP, and spectroscopically oriented configuration interaction (SORCI) calculations have been conducted to give insight into the electronic and geometric structures of the ground and first excited triplet states of the three trigonal-planar complexes. The emission energies for the trigonal planar complexes are more strongly correlated with changes in the Au-I bond length rather than changes in the P-Au-P angle.

Spherical, granular and flake-type powders are used to fabricate polymer-bonded composites of an Fe–Co based alloy and their magnetostrictive properties are compared. Magnetostrictive sensitivity at low applied fields is best for the composites fabricated with flake-type powders. Also, in the case of flake-type powders, a high magnetostriction of 200 ppm is obtained at an applied field of 4.3 kOe under a suitable compressive pre-stress.

Strong interlayer exchange coupling (IEC) and high post-annealing stability are demonstrated for perpendicular synthetic ferrimagnets (p-SyFs) with [Pt/Co]6/Ru/[Co/Pt]3 structures. The observed IEC strength was 2.55 ergs/cm2 for a Ru thickness of 0.35 nm, representing the highest value achieved up to date for similar structures. The IEC remained strong even after annealing at 450oC, for the practically important Ru layer thickness of 0.85 nm. The biquadratic IEC, a parameter quantifying the pinhole effects in SyFs, was confirmed by analyzing the experimental results by using the total energy functional, and its strength increased with decreasing the temperature and Ru layer thickness.

Polymer-bonded composites of a Fe–Co based alloy are fabricated and their magnetic and mechanical properties are characterized. The use of flake-type powders with a thickness of 3–5 μm, instead of conventional spherical powders, is the key to good magnetostrictive properties and this is made possible by suitable design of the alloy (Fe36Co62Ge2) and the development of a pulverization process. The composites exhibit high magnetostriction of 105 ppm measured at an applied field of 4.3 kOe (70 ppm at 1 kOe). Large compressive strength of 42 MPa is also obtained for the composites, indicating solid bonding of flake-type powders by the polymer.

Solutions containing the components Au(+), dpae (dpae is 1,2 bis-(diphenylarsino)ethane), and X(-) (X is Cl, Br, or I) can produce two different types of crystals with the composition Au(2)(μ-dpae)X(2): colorless blocks and colorless needles. Crystallographic studies of these crystals show that they are polymorphs with different structural motifs. In the α-polymorphs, which are isostructural, individual molecules of Au(2)(μ-dpae)X(2) form discrete dimers through two identical Au···Au contacts. In the β-polymorphs, which each have unique crystallographic parameters, the Au(2)(μ-dpae)X(2) molecules assemble into polymeric chains through aurophilic interactions. The Au···Au contacts in the α-polymorph (3.1163(2), 3.1064(3), and 3.0842(2) Å for Cl, Br, I, respectively) are somewhat shorter than those in the β-polymorph (3.1668(3), 3.1042(8), and 3.1046(2) for Cl, Br, I respectively). The systematic study we now report shows an increase in the strength of this aurophilic interaction for the α-form in the series X = ClBrI, which is in good agreement with theoretical studies by Pyykkö and his co-workers.

The free layer switching characteristics in magnetic tunnel junctions with the structure NiFe/AlO x /Co ( y nm)/Ru/Co (7– y nm)/FeMn/NiFe are investigated as functions of the relative Co layer thickness and the cell size by computer simulation. The bias field varies linearly with y , and the relative Co layer thickness dependence of the bias field is greater at smaller cell dimensions. At y =4, the bias field of the free layer remains nearly unchanged with the cell size, due to the balance of the stray field contribution from neighboring layers. The contribution from the lower permalloy layer (next to the FeMn) is found to be not small. The calculated hysteresis loops are in qualitative agreement with the experimental results.

Results are reported from a Monte Carlo study of the vacancy formation energy and the configurational vacancy formation entropy in monatomic crystals and in intermetallic compounds as a function of vacancy concentration. Simulations have been carried out for both square and bcc lattices. Although the results have been obtained for the case in which the lattice energy is determined by nearest-neighbour central pairwise interactions only, the results are of more general interest. Contrary to calculations based on the Bragg-Williams approximation, a very significant configurational contribution to the excess vacancy formation entropy may exist at vacancy concentrations often encountered in intermetallic compounds. The vacancy formation energy, often assumed constant in analytical treatments, may also change quite significantly with vacancy concentration.

Results are reported from Monte Carlo simulations of non-stoichiometric compounds with the B 2 structure and which contain a high concentration of vacancies. The model chosen is a rigid lattice with nearest-neighbour atom interactions only. The vacancy concentrations evaluated correspond with two-phase equilibrium and not those obtained by minimising the single phase free energy. The partial thermodynamic properties of the components are evaluated along the phase equilibrium boundary together with the concentrations of defects on the two sub-lattices. The triple-defect assumption, frequently used in analytical treatments for vacancies in these compounds, is shown to be of very limited value.

The relations between the thermodynamic properties of the unary lattice gas and the equivalent binary substitutional and interstitial alloys are discussed. New methods for the estimation of the partial particle energy in a lattice gas from Monte Carlo simulations in both the petit and grand canonical ensembles are presented and evaluated. Taken together with well established procedures for estimating the particle chemical potential and more recent procedures for estimating the lattice gas pressure, it becomes possible, for the first time, to obtain reliable determinations of both the partial and integral quantities for internal energy, entropy and free energy at a given temperature and composition in a rigid binary alloy from the one Monte Carlo experiment in either ensemble. Some illustrative results are given for the square lattice with nearest neighbour interactions.