Raman spectra for the Bi₄Ge_3-xTi_xO₁₂ ceramic system in the wavenumber range 10-1000 cm^-1 are reported, indicating an order-disorder phase transition at x = 0.4. Pressure- and temperature-dependent Raman spectra for Bi₄Ge_2.8Ti_O.2O₁₂ provide evidence for order-disorder behavior of this phase transition. A pressure-induced amorphization of crystalline of Bi₄Ge_2.8Ti_0.2O₁₂ occurs at 10.4 GPa. The two lowest phonon modes at 27 and 44 cm^-1 of Bi₄Ti₃O₁₂ are assigned to vibrations of a Bi - Bi weak metal bond and effects of Ge ion content, pressure and temperature on the phonon modes are discussed.

J. F. Meng;P. S. Dobal;R. S. Katiyar;广田 邹

Journal of Raman Spectroscopy

1998-12

An investigation on the structural stabilities and electronic properties of SrX (X = S, Se and Te) under high pressure is conducted using the first-principles calculation based on density functional theory (DFT) with the plane wave basis set as implemented in the CASTEP code. Our results demonstrate that the sequence of the pressure-induced phase transition of the three compounds is the NaCl-type (B1) structure (Fm3m) to the CsCl-type (B2) structure (Pm3m). The phase transition and the metallization pressures are determined theoretically. The pressure effect on the optical properties is discussed. The results are compared with the previous calculations and experimental data.

Xiao Cui Yang;Ai Min Hao;Jie Yang;Yong Hao Han;Gang Peng;Chun Xiao Gao;广田 邹

Chinese Physics Letters

2008-5-1

High-density, vertically aligned CrO₂ nanowire arrays were obtained via atmospheric-pressure CVD assisted by AAO templates. The CrO ₂ nanowire arrays show remarkably enhanced coercivity compared with CrO₂ films or bulk. It was found that the length of the nanowires is greatly influenced by the pore diameter of the AAO template used. The growth mechanism and the pore size dependence of the CrO₂ nanowire arrays are discussed. The present method provides a useful approach for the synthesis of CrO₂ nanowire arrays. Such highly ordered nanowire arrays within an AAO template may have important applications in ultrahigh-density perpendicular magnetic recording devices and the mass production of spintronic nanodevices.

Qiang Zhao;Gehui Wen;Zhigang Liu;Yinbo Fan;广田 邹;Li Li;Rongkun Zheng;Simon P. Ringer;Ho Kwang Mao

Nanotechnology

2011-3-25

The film-fabricating technology has been used to prepare the microcircuit on diamond anvil for resistivity measurement under extreme conditions. We chose molybdenum as the electrode material and alumina as the insulator and protective material. The sample thickness measurement was conducted and then the resistivity correction was performed under different thickness. The experimental error was proved to be less than 10%. By mounting alumina film between diamond anvil and microcircuit, high-temperature performance of a laser heating diamond anvil cell was improved obviously, which is available for in situ resistivity measurement under high pressure and high temperature. Meanwhile, the impedance spectroscopy of a powdered semiconductor sample was detected. Through the impedance arcs obtained, the grain boundary contribution to the resistivity can be well distinguished.

Chunxiao Gao;Chunyuan He;Ming Li;Yonghao Han;Yanzhang Ma;广田 邹

Journal of Physics and Chemistry of Solids

2008-9

In situ electrical resistivity measurement of powdered CdTe has been performed under high pressure using a diamond anvil cell equipped with a microcircuit. With the pressure increasing from 2.7 to 3.8GPa, a sharp decrease in resistivity of over three orders of magnitude is observed. This is due to the appearance of rock-salt CdTe. At about 6.5GPa a resistivity inflexion appears which has not been reported before. It is caused by the obvious decrease of band gap in certain symmetry directions of the Brillouin zone of rock-salt CdTe. From 6.5 to 10GPa, the descending trend of the resistivity turns gently. At about 10GPa, a cusp corresponding to the transition to the Cmcm phase is distinguished. Between 10 and 38GPa, three leap points have been detected at 15.5GPa, 22.2GPa and 30GPa, which imply abundant electronic phase transitions of CdTe. Resistivity measurements were also performed in a wide temperature range from liquid nitrogen temperature (77K) to 450K. It is proved that rock-salt CdTe does not show a typical metallic transport character. In the pressure range of 6.0-7.0GPa, CdTe has a band gap of about 445meV. The relationship of lnρ to 1/T is also fitted linearly to yield the ionization energy of impurities at different pressures.

Chunyuan He;C. X. Gao;B. G. Liu;M. Li;X. W. Huang;A. M. Hao;C. L. Yu;D. M. Zhang;Y. Wang;洪武 刘;Y. Z. Ma;广田 邹

Journal of Physics Condensed Matter

2007-10-24

On the basis of extension architectonics, this paper researches the extension data mining and its knowledge discovery for extension interior color design. Facing the extension interior color design, with regard to the extended design data, the paper, based on the design data, through the extended mining method finds dynamic process of useful color design knowledge which can be expanded and innovated, and through flexible method adapts to multiple design application which is under different mining targets. Through data acquisition, extension analysis and extension classification to the color design data of mixed structure, the paper designs categorical extension sets according to problem model, conducts extension transformation flexibly within limited domain range, finds meaningful categorical design rules, discovers knowledge rules and then carries flexible application. The purpose of this paper is to explore a datamation designing road which can solve contradictory issues and innovation issues of color design.

Hui Ma;广田 邹

Boletin Tecnico/Technical Bulletin

2017-7-24

The composite of hollow glass microspheres coated by SnO₂ nanoparticles has been successfully fabricated via sol-gel method. The phase structures, morphologies, particle size, shell thickness, chemical compositions of the composite have been characterized by XRD, FESEM, and EDX. The results show that SnO₂ coating on hollow glass microspheres can be achieved, and the coating layers are constituted by SnO₂ nanoparticles of mean size ca. 15 nm. The SnO₂ coating layers grow thicker with the increased concentration of SnCl₄. The effects of parameters (reaction temperature, concentration of NaOH and SnCl₄, and time) were investigated to yield SnO₂ coating on hollow glass microspheres, and the UV-vis absorption spectra of the composites were studied.

Jing Xu;Haibin Yang;Qingjiang Yu;Lianxia Chang;Xiaofen Pang;Xiang Li;Hongyang Zhu;Minghui Li;广田 邹

Materials Letters

2007-3

FT-IR spectroscopy have been used for identifying both the structure of BN and the intensity of the compressive stress in cubic boron nitride (c-BN) film prepared by a unbalanced rf (13.56 MHz) magnetron sputtering of a hexagonal boron nitride target in a mixture argon and nitride discharge. A T(temperature) - V(negative bias) phase diagram was obtained using the phase structure identify by IR spectra. Comparing the reflection infrared spectra (RIR) with the transmission infrared spectra (TIR) measured from same c-BN film, it is firstly found that RIR peak position of c-BN is lower than TIR peak position of c-BN, this means that the compressive stress on the surface layer of c-BN film is smaller than that inside c-BN film, may be this is the reason why thicker c-BN film can not be synthesized. A higher IR peak position of 1064 cm^-1 and a lower peak position 1004.7 cm^-1 were detected from a broken and partly peeled off c-BN film. The peak position of 1064 cm^-1 agrees with that of bulk c-BN at 1065 cm^-1 which was synthesized at high temperature and high pressure, while the peak position of 1004.7 cm^-1 accords well with the result calculated (1004 cm^-1) by Wentzcovith and it may be closes to that of the stress free value of c-BN. Using the result measured by Ulrich, the shift rate of IR peak position of c-BN in the films is about 3.8 cm^-1/Gpa to be obtained.

Yongnian Zhao;Bing Zhao;Zhi He;Yanchun Tao;广田 邹

Spectroscopy Letters

1998

p-Type nano-ZnFe ₂O ₄ semiconductors were gained by high-prssure treatment. Surface photovoltaic spectrum(SPS) and transient photovoltaic technology(TPV) were used for studying the photogenerated charge of nano-ZnFe ₂O ₄. Results show that the photovoltaic behavior of nano-ZnFe ₂O ₄ changed as the processing pressure increased. When the processing pressure was higher than 2 GPa, both SPS response interval and peak changed significantly. XPS results show that the non-lattice oxygen entered into the lattice and the content of lattice oxygen increased with the increase of processing pressure. The material changed from oxygen vacancy type to oxygen excess type and the photoelectric properties changed from n-type to p-type when the processing pressure is higher than 2 GPa.

Zi Heng Li;Xu Zou;Gen Li;广田 邹

Chemical Research in Chinese Universities

2012-7

In order to avoid aim blinding and thoughts unclear in the innovation practicing, and to improve the efficiency and stability of innovation, The paper bring forwards innovation stratagems and innovation thoughts of Architectural Design Innovation base on Extenics. From the view points of innovation stratagem, the paper put forwards the stratagem called after blue sea which achieving innovation through digging out new factors and relations, and the stratagem called after red sea which achieving innovation through reconstruction inhere factors and relations. From the view points of innovation thoughts, the paper put forwards the thoughts of four basic approaches which are borrow, syncretize, transform and establish.

Keqi Wang;广田 邹

2011