In-situ preparation of WO_3/TiO_2 composite film with increased photo quantum efficiency on titanium substrate

J. He,Q.Z. Cai,D. Zhu,Q. Luo,D.Q. Zhang,X.W. Li,X. Zhao,W. Sun 한국물리학회 2011 Current Applied Physics Vol.11 No.1

A WO_3/TiO_2 composite film was in-situ prepared in tungstate electrolyte and characterized by Electron microscopy, X-ray diffraction, UV―Vis spectrophotometer and Photoluminescence. The oxide film consists of mixture phases of anatase and rutile, showing porous structures and metallurgical bond with substrate. With the incorporation of WO_3 into TiO_2, the optical absorption edge of TiO_2 filmwas shifted to longer wavelength slightly and the separation between electrons and holes was promoted effectively. WO_3/TiO_2 composite film with increased photo quantum efficiency will be promising in the treatment of environmental pollutants.

Microwave Absorption and Magnetic Properties of Cobalt Ferrites/Carbon Nanotubes Nanocomposites

B. B. Zhang,P. F. Wang,J. C. Xu,Y. B. Han,H. X. Jin,D. F. Jin,X. L. Peng,B. Hong,J. Li,J. Gong,H. L. Ge,Z. W. Zhu,X. Q. Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.5

Owing to the unique microstructure and the excellent dielectric properties, carbon nanotubes(CNTs) were decorated with CoFe2O4 nanoparticles to synthesize the CoFe2O4/CNTs nanocomposites by the solvothermal method. The phase structure, morphology, magnetic properties and microwave absorption performance of the as-prepared CoFe2O4/CNTs were characterized and discussed by X-ray diffraction (XRD), thermal gravity analysis (TGA), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA). All results indicated that the diameter of CoFe2O4 nanoparticles decorating on the surface of CNTs increased with the solvothermal temperature. CoFe2O4/CNTs prepared at 180℃, 200℃ and 220℃ exhibited superparamagnetism, while the other samples presented ferromagnetism at room temperature. And with the increasing solvothermal temperature, the saturation magnetization and coercivity increased up to 72 emu/g and 2000 Oe for the sample prepared at 260℃ (S-26). And the reflection loss of CoFe2O4/CNTs nanocomposites increased with the solvothermal temperature up to -15.7 dB for S-26 with the bandwidth of 2.5 GHz.

Synthesis, spectroscopic investigations, X-ray crystallographic studies and magnetic properties of heterobimetallic Fe(II)-Hg(II) polynuclear complexes

Jin, L. T.,Liu, X. T.,Wang, X. Q.,Wang, L. N.,Zhang, G. H.,Zhu, L. Y.,Xu, D. Informa UK (TaylorFrancis) 2014 Materials research innovations Vol.18 No.2

Structural and magnetic characterization of large area, free-standing thin films of magnetic ion intercalated dichalcogenides Mn_0.25TaS₂ and Fe_0.25TaS₂

Danz, Th,Liu, Q,Zhu, X D,Wang, L H,Cheong, S W,Radu, I,Ropers, C,Tobey, R I IOP 2016 Journal of Physics, Condensed Matter Vol.28 No.35

<P>Free-standing thin films of magnetic ion intercalated transition metal dichalcogenides are produced using ultramicrotoming techniques. Films of thicknesses ranging from 30 nm to 250 nm were achieved and characterized using transmission electron diffraction and x-ray magnetic circular dichroism. Diffraction measurements visualize the long range crystallographic ordering of the intercalated ions, while the dichroism measurements directly assess the orbital contributions to the total magnetic moment. We thus verify the unquenched orbital moment in Fe<SUB>0.25</SUB>TaS<SUB>2</SUB> and measure the fully quenched orbital contribution in Mn<SUB>0.25</SUB>TaS<SUB>2</SUB>. Such films can be used in a wide variety of ultrafast x-ray and electron techniques that benefit from transmission geometries, and allow measurements of ultrafast structural, electronic, and magnetization dynamics in space and time.</P>

Response of dynamic interlaminar stresses in laminated plates under free vibration and thermal load

Zhu, S.Q.,Chen, X.,Wang, X. Techno-Press 2007 Structural Engineering and Mechanics, An Int'l Jou Vol.25 No.6

The response histories and distribution of dynamic interlaminar stresses in composite laminated plates under free vibration and thermal load is studied based on a thermoelastodynamic differential equations. The stacking sequence of the laminated plates may be arbitrary. The temperature change is considered as a linear function of coordinates in planes of each layer. The dynamic mode of displacements is considered as triangle series. The in-plane stresses are calculated by using geometric equations and generalized Hooke's law. The interlaminar stresses are evaluated by integrating the 3-D equations of equilibrium, and utilizing given boundary conditions and continuity conditions of stresses between layers. The response histories and distribution of interlaminar stress under thermal load are presented for various vibration modes and stacking sequence. The theoretical analyses and results are of certain significance in practical engineering application.

Damage assessment of reinforced concrete beams including the load environment

X.Q. Zhu,S.S. Law,H. Hao 국제구조공학회 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.33 No.6

Quantitative condition assessment of structures has been traditionally using proof load test leading to an indication of the load-carrying capacity. Alternative approaches using ultrasonic, dynamics etc. are based on the unloaded state of the structure and anomalies may not be fully mobilized in the load resisting path and thus their effects are not fully included in the measured responses. This paper studies the effect of the load carried by a reinforced concrete beam on the assessment result of the crack damage. This assessment can only be performed with an approach based on static measurement. The crack damage is modelled as a crack zone over an area of high tensile stress of the member, and it is represented by a damage function for the simulation study. An existing nonlinear optimization algorithm is adopted. The identified damage extent from a selected high level load and a low load level are compared, and it is concluded that accurate assessment can only be obtained at a load level close to the one that creates the damage.

Damage assessment of reinforced concrete beams including the load environment

Zhu, X.Q.,Law, S.S.,Hao, H. Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.33 No.6

Quantitative condition assessment of structures has been traditionally using proof load test leading to an indication of the load-carrying capacity. Alternative approaches using ultrasonic, dynamics etc. are based on the unloaded state of the structure and anomalies may not be fully mobilized in the load resisting path and thus their effects are not fully included in the measured responses. This paper studies the effect of the load carried by a reinforced concrete beam on the assessment result of the crack damage. This assessment can only be performed with an approach based on static measurement. The crack damage is modelled as a crack zone over an area of high tensile stress of the member, and it is represented by a damage function for the simulation study. An existing nonlinear optimization algorithm is adopted. The identified damage extent from a selected high level load and a low load level are compared, and it is concluded that accurate assessment can only be obtained at a load level close to the one that creates the damage.

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.

Magnetic Annealing Effects on the Properties of Multilayer BaTiO3/CoFe2O4 Thin Films

Y. Q. Dai,J. M. Dai,X. W. Tang,X. B. Zhu,J. Yang,Q. C. Liu,Y. P. Sun 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12

Multilayer BaTiO3/CoFe2O4 thin films are prepared via a chemical solution deposition methodwith and without magnetic annealing, respectively. The microstructural, magnetic, dielectric andferroelectric properties of the films’ are investigated. The dielectric constant, polarization andmagnetization of the multilayer thin films are improved with magnetic annealing. Moreover, forthe magnetic annealing films, the saturation magnetization measured with the measuring magneticfield vertical to the film surface is much higher than that measured with the field parallel to thefilm surface. These novel phenomena may be caused by the decrease in the clamping of the BaTiO3layer and the arrangement of the induced easy axis in the CoFe2O4 layer caused by the appliedannealing field.

432-μm Laser’s Beam-waist Measurement for the Polarimeter/Interferometer on the EAST Tokamak

Z. X. Wang,H. Q. Liu,Y. X. Jie,M. Q. Wu,T. Lan,X. Zhu,Z. Y. Zou,Y. Yang,X. C. Wei,L. Zeng,G. S. Li,X. Gao 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.8

A far-infrared (FIR) polarimeter/interferometer (PI) system is under development for measurementsof the current-density and the electron-density profiles in the EAST tokamak. The systemwill utilize three identical 432-μm CHCOOH lasers pumped by a CO2 laser. Measurements of thelaser beam’s waist size and position are basic works. This paper will introduce three methods witha beam profiler and several focusing optical elements. The beam profiler can be used to show thespatial energy distribution of the laser beam. The active area of the profiler is 12.4 × 12.4 mm2. Some focusing optical elements are needed to focus the beam in order for the beam profiler toreceive the entire laser beam. Two principles and three methods are used in the measurement. Thefirst and the third methods are based on the same principle, and the second method adopts an otherprinciple. Due to the fast and convenient measurement, although the first method is a special formof the third and it can only give the size of beam waist, it is essential to the development of theexperiment and it can provide guidance for the choices of the sizes of the optical elements in the nextstep. A concave mirror, a high-density polyethylene (HDPE) lens and a polymethylpentene (TPX)lens are each used in the measurement process. The results of these methods are close enough forthe design of PI system’s optical path.