Combustion synthesis and photocatalytic properties of magnetically separable Zn_1-xCd_xS/γ-Fe₂O₃ composites

Liu, J.,Zhang, D.,Pu, X.,Dong, D.,Cai, P.,Seo, H.J. North-Holland 2014 Materials letters Vol.130 No.-

Magnetically separable Zn<SUB>1-x</SUB>Cd<SUB>x</SUB>S/γ-Fe<SUB>2</SUB>O<SUB>3</SUB> (x=0-1) photocatalysts were synthesized by a one-step combustion method. The structures, morphologies, absorbance, optical and photocatalytic properties of the samples were studied by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible spectrophotometry and photoluminescence. The experimental results show that the formation of hexagonal Zn<SUB>1-x</SUB>Cd<SUB>x</SUB>S and γ-Fe<SUB>2</SUB>O<SUB>3</SUB> and the combination of them were one-pot achieved. The Cd<SUP>2+</SUP> content has a significant influence on the absorbance of visible light and fluorescence properties. The magnetic properties of samples ensure the magnetic separation by using a magnet. CdS/γ-Fe<SUB>2</SUB>O<SUB>3</SUB> shows the best photocatalytic performance compared with other samples, ascribed to its small energy band gap and matching energy band structure between CdS and γ-Fe<SUB>2</SUB>O<SUB>3</SUB>. Moreover, no obvious deterioration was observed in the stability tests.

Boron adsorption mechanism of a hybrid gel derived from tetraethoxysilane and bis(trimethoxysilylpropyl)amine

Liu, H.,Qing, B.,Ye, X.,Guo, M.,Li, Q.,Wu, Z.,Lee, K.,Lee, D.,Lee, K. 한국물리학회 2009 Current Applied Physics Vol.9 No.4_SUP

An organic/inorganic hybrid gel was prepared with tetraethoxysilane (TEOS) and bis(trimethoxysilylpropyl)amine (TSPA) as precursors. The adsorption of boron on the hybrid gel in aqueous solutions was investigated comprehensively by varying the initial boron concentration, pH, ionic strength, and temperature. The equilibrium adsorption amount of boron increases with the increase in initial boron concentration and ionic strength, but decreases with the increase in temperature. The adsorption amount exhibits a maximum at initial pH of 4-10. Boron appears to be adsorbed in both H<SUB>3</SUB>BO<SUB>3</SUB> and B(OH)<SUB>4</SUB><SUP>-</SUP> forms through the hydrogen bonding, electrostatic and hydrophobic attractions.

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.

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.

Surface segregation and oxidation of Pt₃Ni(111) alloys under oxygen environment

Lee, H.C.,Kim, B.M.,Jeong, C.K.,Toyoshima, R.,Kondoh, H.,Shimada, T.,Mase, K.,Mao, B.,Liu, Z.,Lee, H.,Huang, C.Q.,Li, W.X.,Ross, P.N.,Mun, B.S. Elsevier Science Publishers 2016 CATALYSIS TODAY - Vol.260 No.-

<P>Utilizing ambient pressure X-ray photoelectron spectroscopy (AP-XPS), the surface segregation and oxidation of Pt3Ni(1 1 1) alloys are investigated as a function of temperature and oxygen pressure. The in situ AP-XPS measurements of oxygen oxidation process show that the Pt 'skin' surface is not stable under the exposure of oxygen pressure of 100 mTorr at room temperature. As the temperature and pressure are elevated, the formations of Ni2O3, NiOx, and NiO are observed on surface while Pt atom starts to reduce its adsorbed oxygen, which is a clear sign of surface segregation of Ni to surface. Upon the evacuation of oxygen gas, i.e. ultrahigh vacuum condition, both of NiOx and NiO oxide get reduced and Ni2O3 remains on the surface. The DFT calculation is employed to explain the formation of surface oxides under oxidation condition. (C) 2015 Elsevier B.V. All rights reserved.</P>

Microstructural Stability and Creep Performance of a Novel Low-Cost Single Crystal Superalloy

Z. H. Tan,X. G. Wang,Y. L. Du,Y. M. Li,Y. H. Yang,J. L. Liu,J. D. Liu,J. G. Li,Y. Z. Zhou,X. F. Sun 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The increasing pursuit of advanced aero-engines with lower ratio between the cost and performance has greatly promotedthe demanding of single crystal superalloys characterized by low cost and outstanding temperature capability. In this study,a novel low-cost single crystal superalloy was designed and the creep tests as well as micro-characterization were carried outon the experimental alloy. The results illustrated that the novel single crystal alloy exhibited an ideal microstructural stabilitywithout precipitating TCP phases, after long-term thermal exposure at the ultimate service temperature of third generationsingle crystal superalloys. Moreover, the experimental alloy with only 3 wt% Re addition demonstrated remarkable creepresistance and maintained a very low minimum creep rate at 1100 °C/137 MPa and 1120 °C/137 MPa, while the accumulationand coalescence of micro-pores had eventually led to the alloy fracture. Apart from that, the compact interfacial dislocationnetworks the 2nd γ′ phase were observed after high-temperature creep rupture, and the typical a < 010 > superdislocationswith relatively poor mobility was found at 1120 °C. At 760 °C/800 MPa, both the minimum creep velocity and entire creepstain was increased evidently, however, the ultimate creep rupture life of the alloy had still reached 200 h. The correspondingdeformation mechanism was identified as the combination of superdislocation pairs shearing and a/3 < 121 > partial dislocationcutting the γ′ phase with a SISF being generated. In general, the novel single crystal alloy characterized by remarkablemechanical properties and cost reduction possesses a great potential for future application in the advanced aircraft engines.

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>

A novel high-performance H-gate U-channel junctionless FET

Jin, X.,Yang, G.,Liu, X.,Lee, J. H.,Lee, J. H. Springer Science + Business Media 2017 Journal of Computational Electronics Vol.16 No.2

<P>A novel high-performance H-shape-gate U-shape-channel junctionless FET (HGUC JL FET) is proposed. Compared with the saddle junctionless FET, the proposed HGUC JL FET shows better subthreshold characteristics and higher on-current. Its electrical properties were extensively investigated by studying the influence of variation of design parameters such as the H-gate thickness, the source/drain extension region height, and the gate oxide thickness and material. Compared with conventional structures, the proposed HGUC JL FET shows better performance, especially on scaling down to several nanometers. The reverse leakage current is also effectively restrained and the I-on/I-off ratio greatly improved through design optimization.</P>

Complex Multicolor Tilings and Critical Phenomena in Tetraphilic Liquid Crystals

Zeng, X.,Kieffer, R.,Glettner, B.,Nurnberger, C.,Liu, F.,Pelz, K.,Prehm, M.,Baumeister, U.,Hahn, H.,Lang, H.,Gehring, G. A.,Weber, C. H. M.,Hobbs, J. K.,Tschierske, C.,Ungar, G. American Association for the Advancement of Scienc 2011 Science Vol.331 No.6022

<P>T-shaped molecules with a rod-like aromatic core and a flexible side chain form liquid crystal honeycombs with aromatic cell walls and a cell interior filled with the side chains. Here, we show how the addition of a second chain, incompatible with the first (X-shaped molecules), can form honeycombs with highly complex tiling patterns, with cells of up to five different compositions ('colors') and polygonal shapes. The complexity is caused by the inability of the side chains to separate cleanly because of geometric frustration. Furthermore, a thermoreversible transition was observed between a multicolor (phase-separated) and a single-color (mixed) honeycomb phase. This is analogous to the Curie transition in simple and frustrated ferro- and antiferromagnets; here spin flips are replaced by 180° reorientations of the molecules.</P>

In-situ high-energy synchrotron X-ray diffraction study of micromechanical behavior of multiple phases in Ni₄₇Ti₄₄Nb₉ shape memory alloy

Sun, G.A.,Wang, X.L.,Wang, Y.D.,Woo, W.C.,Wang, H.,Liu, X.P.,Chen, B.,Fu, Y.Q.,Sheng, L.S.,Ren, Y. Elsevier Sequoia 2013 Materials science & engineering. properties, micro Vol.560 No.-

High-energy synchrotron X-ray diffraction technique was used to in-situ characterize microstructure, lattice strain, and phase transition behavior of a Ni<SUB>47</SUB>Ti<SUB>44</SUB>Nb<SUB>9</SUB> shape memory alloy. Phase transformation kinetics and deformation mechanisms were studied under a uniaxial tension at three testing temperatures, i.e., -70<SUP>o</SUP>C, 25<SUP>o</SUP>C, and 150<SUP>o</SUP>C. At a testing temperature of -70<SUP>o</SUP>C, a complicated phase transformation with four stages of micromechanical deformation was identified which is associated with changes of martensite substructures. At room temperature of 25<SUP>o</SUP>C, there was no stress-induced selection process of variants of B19' phases observed. Whereas at a testing temperature of 150<SUP>o</SUP>C, there was no any phase transformation observed. It is verified that β-Nb phase, an effective stabilizer for the austenite, delays the process of martensitic transformation and relaxes the strain energy without strengthening the matrix. This new finding is important to understand the relationship between the micromechanical deformation behavior and phase transformations in the Ni<SUB>47</SUB>Ti<SUB>44</SUB>Nb<SUB>9</SUB> SMA.