Structure and Stacking Faults in Sr₂Be₂B₂O7 Crystal

X. Y. Meng,X. H. Wen,G. L. Liu 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.4

Inspired by the successful study on the structure instability of Na₂Al₂B₂O7 (NABO), we extend our interest to a theoretical study, by using density functional theory, on the crystal structures of Sr₂Be₂B₂O7 (SBBO), which possess pretty much the same [M₂B₂O7]∞ (M = Be, Al) double layers as those of the NABO crystal. The energy differences of the SBBO structural variants are found to be so slight that stacking faults could readily occur in the crystal. We propose that different phases may coexist in the same SBBO crystallite, forming domain structure similar to those of NABO which were found by using single-crystal X-ray diffraction. The structural stability of SBBO is closely related to the cohesion forces between [Be₂B₂O7 ∞ layers. A similar structure analysis can be extended to the SBBO isomorphism. Inspired by the successful study on the structure instability of Na₂Al₂B₂O7 (NABO), we extend our interest to a theoretical study, by using density functional theory, on the crystal structures of Sr₂Be₂B₂O7 (SBBO), which possess pretty much the same [M₂B₂O7]∞ (M = Be, Al) double layers as those of the NABO crystal. The energy differences of the SBBO structural variants are found to be so slight that stacking faults could readily occur in the crystal. We propose that different phases may coexist in the same SBBO crystallite, forming domain structure similar to those of NABO which were found by using single-crystal X-ray diffraction. The structural stability of SBBO is closely related to the cohesion forces between [Be₂B₂O7 ∞ layers. A similar structure analysis can be extended to the SBBO isomorphism.

Hardness Prediction and First Principle Study of Re-123(Re = Y, Eu, Pr, Gd) Superconductors

Liu, Weiwei,Zhou, Y.P.,Feng, X.L. Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.12

The chemical bond parameters of Y-123, Eu-123, Pr-123 and Gd-123 compounds have calculated using the chemical bond theory of complex crystals. Their hardness have been predicted by the chemical bond definition of hardness. The calculated results indicate that the Ba-O and RE-O types of bond have a lower covalent character and the Cu-O types of bond have greater covalency. The hardness values increase as the unit cell volume of the rare earth superconductor structures decrease.

Annealing Dependence of Solution-Processed Ultra-Thin ZrOx Films for Gate Dielectric Applications.

Liu, G X,Liu, A,Meng, Y,Shan, F K,Shin, B C,Lee, W J,Cho, C R American Scientific Publishers 2015 Journal of nanoscience and nanotechnology Vol.15 No.3

<P>Ultra-thin ZrOx thin films on Si substrates were prepared by sol-gel technique and processed with different methods (baked on hot plate at 150 °C, annealed at 500 °C in furnace, and photo-annealed under UV light). The decomposition of the organic groups and the formation of Zr-O bonding in the ZrOx thin films were confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. It is found that the ZrOx thin film annealed under UV light shows decent characteristics, including an ultra-small surface roughness, a low leakage current density of 10(-9) A/cm2 at 1 MV/cm, a large breakdown electric field of 9.5 MV/cm, and a large areal capacitance of 775 nF/cm2.</P>

XRD studies on phase formation and the crystallite structure of BaTiO3 synthesized by HBM: the effect of calcination temperature

X.M. Chen,Y. Zhang,W.W. Kong,X.B. Bian,J.P. Zhou,P. Liu 한양대학교 세라믹연구소 2010 Journal of Ceramic Processing Research Vol.11 No.4

Barium titanate (BaTiO3, or BT) powders were synthesized via a solid state reaction of BaCO3-TiO2 by combining a highenergy ball milling (HBM) technique and a calcination method. Using X-ray diffraction (XRD) methods with a Rietveld refinement, the effects of calcination temperature on the phase formation and crystallite structure of BT powders were studied. It is found that by means of HBM the synthesis temperature for obtaining BT single phase is decreased to 960 oC, which is much lower than that required by the conventional solid-state reaction process, and the crystallite structure of BT is in the (pseudo)cubic form. As the calcination temperature is increased to 980 oC, the structure of BT crystallites transforms from the (pseudo)cubic to the tetragonal form. With an increase in the calcination temperature, both the tetragonality (c/a-1) and crystallite size are increased.

Bioefficacy of Lysine from L-lysine Sulfate and L-lysine⋅HCl for 10 to 20 kg Pigs

Liu, M.,Qiao, S.Y.,Wang, X.,You, J.M.,Piao, X.S. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.10

The objective of this study was to compare the bioefficacy of L-lysine sulfate relative to L-lysine${\cdot}$HCl for 10 to 20 kg pigs. Two experiments were conducted to determine the bioefficacy of the two sources of lysine using daily gain, feed conversion, plasma urea nitrogen and nitrogen retention as the response criteria. In experiment 1, 168 crossbred barrows ($Landrace{\times}Large$ White), weaned at $28{\pm}3$ d ($9.07{\pm}0.78$kg body weight), were allotted to one of seven dietary treatments in a $2{\times}3$ (two lysine $sources{\times}three $ lysine levels) factorial arrangement of treatments with an added negative control treatment group. The basal diet was based on corn, peanut meal and soybean meal and provided 0.67% lysine. The basal diet was supplemented with 0.1, 0.2 or 0.3% lysine equivalents supplied from either L-lysine sulfate or L-lysine${\cdot}$HCl. Each treatment was fed to six pens of pigs with four pigs per pen. The trial lasted 21 days. The relative bioefficacy value of lysine in L-lysine sulfate using daily gain, feed conversion and plasma urea nitrogen as response criteria was 1.01, 1.05 and 1.04 of the lysine in L-lysine${\cdot}$HCl, respectively. In experiment 2, 42 crossbred ($Landrace{\times}Large$ White) pigs ($16.03{\pm}1.58$ kg body weight) were housed in stainless steel metabolism cages for 10 d and fed the seven diets used in the nitrogen-balance trial. The relative bioefficacy value of L-lysine sulfate was estimated to be 0.95 as effective as L-lysine${\cdot}$HCl for nitrogen retention on an equimolar basis. The t-test analysis revealed that bioefficacy of lysine in L-lysine sulfate was not significantly different from lysine in L-lysine${\cdot}$HCl, which was set at 1.00. In conclusion, L-lysine sulfate can be used instead of L-lysine${\cdot}$HCl to fortify lysine-deficient diets fed to 10 to 20 kg pigs.

Room-temperature ferromagnetism in highly Cr-doped II-Mn-VI magnetic semiconductor Cd1−x−yMnxCryTe

Hwang, Y. H.,Shen, S.,Liu, X.,Furdyna, J. K.,Dobrowolska, M.,Um, Y. H. American Physical Society 2013 Physical review. B, Condensed matter and materials Vol.88 No.7

Thermoelectric properties of Gd, Y co-doped Ca3Co4O9+δ

H.Q. Liu,X.B. Zhao,T.J. Zhu,Y. Song,F.P. Wang 한국물리학회 2009 Current Applied Physics Vol.9 No.3

The Ca3-x-yGdxYyCo4O9+δ precursor powders were synthesized by the polyacrylamide gel method. The powders were sintered by the spark plasma sintering (SPS). The DTA analysis showed that the synthesis temperature of Ca3Co4O9+δ was about 933 K, which is lower than that of the conventional citric acid method. The resistivities, the Seebeck coefficients and the thermal conductivities of the samples were measured from room temperature to 973 K. The Seebeck coefficients and the resistivities of the doped samples were remarkably enhanced due to the decrease of the carrier concentration, whereas the thermal conductivities of them were decreased due to the impurity scattering effect. The maximal ZT value of 0.26 was obtained at 973 K for Ca2.7 Gd0.15 Y0.15Co4O9+δ. The Ca3-x-yGdxYyCo4O9+δ precursor powders were synthesized by the polyacrylamide gel method. The powders were sintered by the spark plasma sintering (SPS). The DTA analysis showed that the synthesis temperature of Ca3Co4O9+δ was about 933 K, which is lower than that of the conventional citric acid method. The resistivities, the Seebeck coefficients and the thermal conductivities of the samples were measured from room temperature to 973 K. The Seebeck coefficients and the resistivities of the doped samples were remarkably enhanced due to the decrease of the carrier concentration, whereas the thermal conductivities of them were decreased due to the impurity scattering effect. The maximal ZT value of 0.26 was obtained at 973 K for Ca2.7 Gd0.15 Y0.15Co4O9+δ.

Laser Raman detection of platelet as a non‐invasive approach for early and differential diagnosis of Alzheimer's disease

Chen, P.,Tian, Q.,Baek, S.J.,Shang, X.L.,Park, A.,Liu, Z.C.,Yao, X.Q.,Wang, J.Z.,Wang, X.H.,Cheng, Y.,Peng, J.,Shen, A.G.,Hu, J.M. WILEY‐VCH Verlag 2011 Laser physics letters Vol.8 No.7

<P><B>Abstract</B></P><P>Early and differential diagnosis of Alzheimer's disease (AD) is a problem that puzzled many doctors. Reliable markers in easy‐assembling samples are of considerable clinical diagnostic value. In this work, laser Raman spectroscopy (LRS) was developed a new method that potentially allows early and differential diagnosis of AD from the platelet sample. Raman spectra of platelets isolated from different ages of AD transgenic mice and non‐transgenic controls were collected and analyzed. Multilayer perceptron networks (MLP) classification method was used to classify spectra and establish the diagnostic models. For differential diagnosis, spectra of platelets isolated from AD, Parkinson’s disease (PD) and vascular dementia (VD) mice were also discriminated. Two notable spectral differences at 740 and 1654 cm<SUP>–1</SUP> were revealed in the mean spectrum of platelets isolated from AD transgenic mice and the controls. MLP displayed a powerful ability in the classifying of early, advanced AD and the control group, and in differential diagnosis of PD and advanced AD, as well as VD and advanced AD. The results suggest that platelet detecting by LRS coupled with MLP analysis appears to be an easy and accurate method for early and differential diagnosis of AD. This technique could be rapidly promoted from laboratory to the hospital. (© 2011 by Astro Ltd., Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA)</P>

Variation of magnetic properties with different annealed temperatures in the Ni_3[Fe(CN)_6]_2ㆍXH_2O

M. Liu,X.F. Bian,Y.F. Xia,Z. Bao,H.S. Wu,M.X. Xu 한국물리학회 2011 Current Applied Physics Vol.11 No.3

Molecular magnet nickel(II) hexacyanoferrate(III) powder Ni_3[Fe(CN)_6]_2ㆍXH_2O was prepared by coprecipitation method. The coprecipitated powder was annealed in vacuum at different temperatures of 140,and 160 ℃. Water molecules contained in Prussian blue analogues were removed by heating. The annealing of Ni^II ferricyanide induced an inner charge transfer from Ni^II towards Fe^III to form the mixed valence system Ni(II) Ni(III) ferri-ferro-cyanide. Variation of magnetic properties with different annealed temperatures was studied by elemental analysis, powder X-ray diffraction, transmission electron microscopy, Fourier transform infrared, and Mössbauer and magnetization measurements. The differences in magnetic phase transition temperature, coercivity, remanence and effective magnetization are studied. Differences in magnetic properties may be attributed to a partial charge transfer from Ni^II to Fe^III.

Hardness Prediction and First Principle Study of Re-123(Re = Y, Eu, Pr, Gd) Superconductors

Weiwei Liu,Y. P. Zhou,X. L. Feng 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.12

The chemical bond parameters of Y-123, Eu-123, Pr-123 and Gd-123 compounds have calculated using the chemical bond theory of complex crystals. Their hardness have been predicted by the chemical bond definition of hardness. The calculated results indicate that the Ba-O and RE-O types of bond have a lower covalent character and the Cu-O types of bond have greater covalency. The hardness values increase as the unit cell volume of the rare earth superconductor structures decrease.