Table of Content

15 September 2017, Volume 46 Issue 9

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Growth, Spectral Properties and LD Pumped Laser Performances of Cr,Nd:GSAG Crystal

XU Jin-rui;ZHANG Qing-li;PENG Fang;WANG Xiao-fei;DOU Ren-qin;LUO Jian-qiao;SUN Gui-hua;DING Shou-jun;SUN Dun-lu

2017, 46(9):  1653-1659. 

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Cr,Nd:GSAG is one type of laser crystal with high performances , but there are few research on its lasing properties by LD pumping .In this work, a Cr,Nd:GSAG crystal was grown by Czochralaki method , its chemical composition , structure and lasing performances were investigated .By measuring the X-ray rocking curve of (111) crystallographic plane of Cr ,Nd:GSAG crystal, the full at half maximum ( FWHM) of the diffraction peak is 0.055°.Its atomic structural parameters and temperature factors were obtained by Rietveld refinement to X-ray diffraction data .The strongest absorption peak of Cr ,Nd:GSAG crystal locates at 808.6 nm and the absorption cross section is 3.38 ×10 -20 cm2 .The strongest emission peak of Cr ,Nd:GSAG crystal under 808 nm excitation locates at 1060 nm and the stimulated emission cross section is 6.04 ×10 -20 cm2 .The fluorescence lifetime of laser upper level 4 F3/2 was measured to be 274 μs.A 1060 nm laser output was achieved by 808 nm LD pumping in the continuous-wave mode .The maximum output power of 0.513 W is obtained with an incident pump power of 8.88 W, corresponding to a slope efficiency of 6.73; and an optical-to-optical conversion efficiency of 5.78;.Besides, energy transfer mechanism between Cr 3+and Nd3+in Cr,Nd:GSAG crystal was discussed .

Growth and Spectral Properties of Nd3+Dopedα-NaYF4 Single Crystal

ZHANG Jian;XIA Hai-ping;JIANG Dong-sheng;WANG Cheng;FENG Zhi-gang;JIANG Hao-chuan;CHEN Bao-jiu

2017, 46(9):  1660-1664. 

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The bulk single crystal of Nd 3+doped α~NaYF4 was in a molar ratio of starting material NaF:KF:YF3:NdF3 =30:18:47:5 grown by an improved flux-Bridgman method using KF as flux .XRD pattern shows that the incorporation of a small amount of Nd 3+ ions did not change the cubic phase structure of the single crystal .The actual doping concentration of Nd 3+ ions in the single crystal was determined to be 3.15mol;, which was smaller than the incorporation concentration .The results show that rare earth ions have segregation phenomenon in the crystal .According to the absorption spectrum , it can be seen that the strongest absorption peak at 800 nm.The maximum absorption coefficient αand the maximum absorption cross section σabs are respectively 0.91 cm -1 and 0.138 ×10 -20 cm2 .The emission spectrum has three peaks ranging from 800 nm to 1500 nm under 800 nm excitation .The strongest peak at 1052 nm produced by the 4 F3/2 level to the 4 I11/2 level transition .The fluorescence lifetime was measured to be 35 μs.The optical properties of Nd 3+doped NaYF4 crystal show that it has potential applications in the field of mid infrared laser .

Effect of O, Se and Te Doping on the Electronic Band Structure and Optical Properties of Single Layer MoS2

ZHANG Yao-yu;XIAO Gang;WANG He;LIN Yi-xin

2017, 46(9):  1665-1671. 

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Based on the first principles method of density-functional theory , structural parameters , band structures , redox potentials , density of states , light absorption properties and photocatalysis potential of both pure and O, Se and Te doping single-layer MoS2 were calculated.The results indicate that the lattice parameter and bond length of pure and doped single-layer MoS2 increase with the increase of atomic radius , and the bond angle decrease with atomic radius increasing .The band gap becomes smaller and electrical conductivity become stronger after doping .Pure and doped single-layer MoS2 both have potential as photocatalyst in water splitting .Because the bottom edge of the conduction band is higher than the reduction potential of H 2 O/H2 , and the top edge of the valence band is lower than the oxidation potential of O2/H2 O.However, pure and O-doping single-layer MoS2 have low photocatalytic efficiency due to a extreme imbalance of redox potentials with electron-hole demand .After Se and Te doping , dopped single-layer MoS2 have higher photocatalytic capacity by equilibrating redox potentials and electron-hole demands. Meanwhile, the dopped single-layer MoS2 have better optical absorption , especially for visible light absorption .This research give a helpful support to screen the suitable doping for single-layer MoS2 , and to improve the performance of photocatalytic water splitting .

Growth and Fluorescence Temperature Characteristics of Cr3+Doped MgAl2 O4 Single Crystal Optical Fiber

YU Lu;YE Lin-hua;BAO Ren-jie;ZHANG Xian-wei;WANG Li-Gang

2017, 46(9):  1672-1677. 

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MgAl2 O4 single crystal optical fiber with 0.5at;Cr3+ ions doped has been grown by laser heated pedestal growth method .The crystal structure and fluorescence temperature characteristics were tested by the X-ray diffraction ( XRD), fluorescence emission spectra and fluorescent decay detection . The results indicate that the main phase of MgAl2O4:Cr3 +single crystal fiber was MgAl2O4 crystal phase, and the spinel crystal structure unchanged with the Cr 3+ions doped .With the increase of temperature , the fluorescence intensity of MgAl 2 O4:Cr3+single crystal fiber decreases under a 405 nm LED excitation. Especially, the intensity of 2 E→4 A2 transition decreases apparently .The fluorescence lifetime of the MgAl2 O4:Cr3+single crystal fiber decreases monotonously from 7.74 ms to 0.5 ms in the temperature range from 293 K to 723 K.The MgAl2 O4:Cr3+single crystal fiber is suitable well for fluorescence sensitized material of optical fiber temperature sensors based on fluorescence lifetime due to the relatively long fluorescence lifetime .

Process Research for Growth of CdSe Crystal by Unconstrained Quadratic Physical Gas Phase Method

XIONG Zhu-yun;ZENG Ti-xian;ZHANG Min;CHEN Tai-hong;HUANG Fei;YANG Hui

2017, 46(9):  1678-1682. 

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On the basis of the physics gas phase method , the CdSe crystal with natural appearances was grown by the unconstrained quadratic phase vapor transport method , the size of which is about 6 mm ×7 mm ×2 mm.The microstructure , composition and morphology of the crystal were characterized by XRD , ICP-MS and SEM .The peak intensity of XRD diffraction is high without impurity peaks .The three natural appearances of CdSe crystal are (100), (002) and (110) planes, respectively, and the full width at half maximum ( FWHM ) of the rocking curves are small .The CdSe crystal grown by the unconstrained quadratic phase vapor transport method has less impurity content and higher infrared transmission .SEM observation demonstrates that the cleavage planes is stair-stepping and the stretching direction of the steps are uniform .All the results show that the CdSe crystal grown by the unconstrained quadratic phase vapor transport method has high purity ,crystalline quality and infrared transmission ,and the reason of natural appearances of CdSe crystal was analyzed by BFDH model .

Research Progress on Doping Process and Properties of β-Ga2 O3 Thin Film

ZHANG Hao;DENG Jin-xiang;BAI Zhi-ying;PAN Zhi-wei;KONG Le

2017, 46(9):  1683-1690. 

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β-Ga2 O3 thin film has been considered as one of the most promising materials in the field of photoelectric detector and light emitting devices because of its wide band gap , high stability and low production cost .However , the low conductivity of β-Ga2 O3 has limited its application in some fields . And improving the optical and electrical properties of β-Ga2 O3 thin films by doping method has attracted many researchers'attention.This paper introduces several common doping methods and the effect of doping on the structure and photoelectric properties of β-Ga2 O3 thin film, and the future research work is also prospected .

Synthesis and Photoluminescence of Na3 ZrF7:Er/Yb Nanoparticles

YU Ming-huai;WANG Guang-sheng;YE Shuai;SONG Jun;QU Jun-le

2017, 46(9):  1691-1696. 

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In this paper, Na3ZrF7:Er/Yb nanoparticles (NPs) with core-shell structures were prepared by pyrolytic process , the morphologies , phase and emission spectra of all samples were analyzed .The emission intensity of the Na 3 ZrF7:Er3+2;, Yb3 +20;@CaF2 NPs was enhanced 5 times compared with that of Na3 ZrF7:Er3 +2;, Yb3 +20; under excitation of 980 nm.By coating the tetragonal Yb/Nd codoped NaYF4 on Na3 ZrF7:Er3 +2;, Yb3 +20;@CaF2 NPs, strongly upconverted red emissions of Na3 ZrF7@CaF2@NaYF4 NPs excited by an 808 nm laser were achieved , the red/green emission ratio approached a value of 10, the luminescence mechanism were elucidated .

Luminescent Properties of Sm3+Doped Natural Soda Feldspar ( NaAlSi3 O8 ) Phosphors

Hairegu· tuxun;Tushagu· abuduwufu;Meiheriguli· maimaiti;Aierken· Sidike

2017, 46(9):  1697-1702. 

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through solid state reaction , use the natural soda feldspar host material and Sm 3+as activator. The structure of Sm3+doped soda feldspar samples were characterized with X-ray diffraction(XRD) .we have investigated the emission spectra at room temperature , And find out the optimal doping concentration of rare earth ions.The excitation spectra of NaAlSi 3 O8:Sm3+phosphors reveal intensive excitation bands at 402 nm, which match with near-UV LED chips.The emission spectra of the phosphors exhibit four peaks composed of emission peak at 569 nm, 601 nm, 648 nm, and 713 nm, The luminescence intensity firstly increases and then decreases with increasing Sm 3+ doped amount .The emission reaches the maximum intensity at Sm 3 +doped amount of 0 .06 mol , and the concentration quenching mechanism is the electric dipoleelectric dipole interaction .CIE color coordinates of NaAlSi 3 O8:Sm3+ locate in the orangered region ,and are not influenced by Sm 3+concentration .

Effect of L-Aspartic Acid on the Crystallization of Magnesium Sulfate

YAN Ping-ke;BAI Yang;SUN De-zhi;WEI Hao-ran;GAO Yu-juan;ZHANG Xu

2017, 46(9):  1703-1708. 

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Based on the principle of biomimetic synthesis , anhydrous MgCl 2 and anhydrous Na 2 CO3 were selected as the reaction materials .The growth of crystals was controlled by L-aspartic acid and five inorganic surfactants respectively . XRD、SEM were used to analyze the phase Composition and morphology of the structure .The results show that when the surfactant is L-aspartic acid , the crystal growth is the best .The results show that when the mass fraction of L-aspartic acid is 0 .15;and the pH is 9.5, crystallization of magnesium sulfate with millimeter is formated .The formation mechanism of L-aspartic acid crystals in the process of bionic synthesis of magnesium carbonate was discussed .

Preparation of Polycrystalline Silicon Thin Film by AIC on Graphite Substrate

WEI Li-shuai;CHEN Nuo-fu;ZHANG Hang;WANG Cong-jie;HE Kai;BAI Yi-ming;CHEN Ji-kun

2017, 46(9):  1709-1713. 

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In this paper , graphite/a-Si/Al and graphite/Al/a-Si laminated structures were prepared on graphite substrate by magnetron sputtering , and systematically studied the effects of the samples annealed by conventional annealing ( CTA) and rapid annealing ( RTA) .The poly-Si thin films were characterized by means of X-ray diffraction (XRD), Raman spectroscopy (Raman), and the grain size was calculated by the Scherrer formula , which show that the samples with strong preferred ( 111 ) orientation and high crystallization quality are ideal for epitaxial growth poly-Si thick film cells.At the same time, we established the AIC model to explain the mechanism in the inverted AIC process .

Effect of Substrate Temperature on the Properties of Ta-doped ZnO Thin Films Deposited by Radio Frequency Magnetron Sputtering Method

YANG Tian-qi;LI Cui-ping;CAO Fei-fei

2017, 46(9):  1714-1719. 

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Ta-doped ZnO films were deposited under different substrate temperatures using radio frequency magnetron sputtering . The effects of the substrate temperature on the component , microstructure , morphology , and the optical properties of the films were investigated by energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), scanning electron microscope (SEM), ultraviolet-visible (UV-vis) spectrophotometer, photoluminescence (PL) spectrometer.EDS results verify that Ta elements have been doped into the ZnO films successfully .XRD patterns results show that the structures of the prepared films maintain the hexagonal wurtzite of ZnO and are not influenced by the Ta element as the substitutional impurities .The (002) diffraction peak intensity of Ta-doped ZnO film first increases and then decreases with the increase of substrate temperature .It reaches the maximum value at the substrate temperature of 400 ℃.SEM results show the grain size of the Ta-doped ZnO film becomes bigger when the substrate temperature is increased to 400 ℃ and 500 ℃.UV-vis spectra indicate that the average transmittance of the Ta-doped ZnO film is higher than 80;and the Ta-doped ZnO film deposited without heating the substrate possesses the highest transmittance in visible light range .The band gap energy of Ta-doped ZnO film extracted from the absorption edge of transmission spectra is in the range of 3.34~3. 37 eV.The minimum band gap energy of 3.34 eV is obtained for the Ta-doped ZnO films deposited at the substrate temperature of 500 ℃.PL spectra verified that the Ta-doped ZnO film deposited at 500 ℃have more defects , which can also explain the reduction of the band gap energy .

Effect of Sulfurization Temperature-time Curves on Properties of CZTS Thin Films

LI Qi;JIANG Zhi;YANG Jian;YANG Min;LU Yi-lei;LIU Si-jia;XU Xin;WANG Shu-rong

2017, 46(9):  1720-1727. 

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The prepared sulfur-contained precursors based on sputtering method were sulfurized by different time-temperature profiles during the sulfurization process , and the effect of different time-temperature profiles on CZTS films were investigated by charactering roughness , compactness and homogenous of the CZTS surface .From the SEM results , the grain size of the CZTS gradually increase with slowing the heating rate .Although the large grain size can reduce the grain boundaries , the large grains deteriorate flatness of the CZTS surface .The phases of the film were determined by measuring the composition , crystallization and phase composition , it is indicate that the film is belong to Cu-poor and Zn-rich kesterite phase .The optical and electrical properties of the CZTS films were characterized by measuring the corresponding CZTS film samples without Mo layer .Finally, the CZTS cells with the SLG/Mo/CZTS/CdS/i-ZnO/AZO/Ni/Al-grid structure were fabricated .And the best cell with the efficiency of 3.60;is obtained.

Synthesis of Bi2 WO6 Hierarchical Microsphere Modified by Cu2 O Sphere and Its Photocatalytic Production of Hydrogen and Alkanes

ZHENG Xian-jun;ZHAO Meng;LI Cui-ling;CHEN Ping-ping;WEI Li-fang;WANG Huan-xin

2017, 46(9):  1728-1734. 

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Hierarchical microsphere was prepared by a hydrothermal method , then modified with Cu 2 O sphere by a reduction-precipitation method to obtain Cu 2 O/Bi2 WO6 composites. Phase structure, morphology and optical response property were characterized by XRD , FESEM, TEM, UV-vis DRS and PL.In Cu2 O/Bi2 WO6 composite, 100 nm Cu2 O spheres were nonuniformly adhered to nanoplates of 1.5μm hierarchical microsphere .Modification with Cu 2 O could considerably enhance absorbing ability of ultraviolet-visible light , separation efficiency of photogenerated electron-hole pairs and photocatalytic activity.Using propionic acid as electron donor , performances for production of hydrogen and alkanes via water-splitting process over Cu 2 O/Bi2 WO6 composites have been investigated .Results showed that 5wt;Cu2 O/Bi2 WO6 exhibited better performance for photocatalytic production of hydrogen and alkanes .

Effect of La3 +Doping on the Microstructures and Dielectric Properties of Ca1 -xLaxCu3Ti4O12 Ceramics

LI Wang;LUO Zhe;TANG Lu;XUE Fei;GUO Peng

2017, 46(9):  1735-1739. 

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CaCu3 Ti4 O12 ( CCTO ) ceramics doped by La 3+ were prepared by the solid state reaction method.The phase structures , microstructures, and dielectric properties of the Ca 1-x Lax Cu3 Ti4 O12 ( x=0;, 1;, 3;, 5;, 7;) ceramics were investigated .The mechanism of influence of La 3+doping on the dielectric properties of CCTO ceramics was analyzed .The results show when x is 3;, secondary phases appear , when x is higher than 5;, the ceramic grains become smaller , La3+doping remarkably increases the dielectric constant of CaCu 3 Ti4 O12 ceramics, and the dielectric loss also becomes lower than undoped CaCu 3 Ti4 O12 ceramics over the high frequency range , which improved the general dielectric properties of CCTO ceramics .

Progress on Synthesis and Application of Hydroxyapatite

CHENG Hong-fei;SUN Yi-gao;AN Shuai;QIAO Jun-jie

2017, 46(9):  1740-1747. 

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Hydroxyapatite is ideal bone repair and substitute materials for its novel properties such as good compatibility , stability , bioactivity , bone conduction and biodegradable . However , it has not been widely used so far due to its low strength , poor toughness , not easy to shape and other mechanical properties .The preparation of excellent hydroxyapatite as well as its compounds has become the key point of the present research .This paper domonstrated the origin , development , preparation , application and development prospect of hydroxyapatite based on its research status .Many different synthetic methods like hydrothermal and biomimetic method as well as their advantages and disadvantages were emphasized .The application development process from dense to porous , single to composite even to multiphase as well as accurate control of microstructure of hydroxyapatite was summarized .Besides , the paper researched the clinical application of bionic bone .

Photocatalytic Property Analysis of Ultra Small TiO2 Synthesied by Detonation Method

ZHAO Tie-jun;LI Xiao-jie;WANG Yang;YAN Hong-hao

2017, 46(9):  1748-1754. 

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The particle size is a very important factors for photocatalytic activity of TiO 2 , and the smaller TiO2 has a higher photocatalytic property .A slurry explosive mixed by Ti-contained precursor , ammonium nitrate, hexogen and some polystyrene beads was exploded in a pressure-tight reaction kettle to prepare ultra small TiO2 nanoparticle.The influence of explosive formulation on morphology , dispersivity and particle size was studied .Furthermore, the photocatalytic property of ultra small TiO 2 was tested by degradation of methyl orange solution .It is found that the TiO2 nanoparticles are consisted of rutile and anatase;most of them are spherical or irregular quadrangular; the particle size is about 10 nm; a small amount of particles'size is greater than 20 nm.The crystallinity of TiO2 is good.The explosive formulation has great influence on crystallinity , particle size and dispersivity of TiO 2 .The band gap of TiO2 is about 2.8 eV, which is less than that of anatase and rutile , and it indicates that the ultra small TiO2 can increase the utilization of sunlight .The degradation rate of methyl orange is 30;when the ultra small TiO2 was used to degrade methyl orange solution for 50 min, which is much higher than the TiO 2 and Cu-doped nano TiO 2 prepared by detonation method with larger particle size .The photocatalytic property is improved obviously .

Rapid Crystallized Preparation of Tungsten Based Ceramic Glaze and Its Photocatalytic Performance Research

HUANG Jian-feng;WANG Qing-gang;LIU Yi-jun;PAN Li-min;TONG Ji-feng;LI Jia-yin;HUANG Ling-yan

2017, 46(9):  1755-1758. 

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Tungsten base ceramic crystalline glaze materials was prepared in this article and the WOP 2 O7 phases structure was obtained .By scanning electron microscopy (SEM) analysis found that its surface is characterized by significantly crystallization morphology , further EDS spectrum analysis found that the surface topography is tungsten crystalline glaze and the bottom is glaze phase .In the photocatalytic performance research found that the glaze layer material under ultraviolet visible light irradiation show certain catalytic degradation of rhodamine B solution , which provides the reference for ability of a functional value for ceramic crystalline glaze materials .

Preparation and Photoluminescence Investigation of Sr3 Lu( PO4 ) 3:Pr3+Phosphors

WANG Li-juan;YANG Xiao-zhan;MA Shi-zhang;WU Jia-ping

2017, 46(9):  1759-1761. 

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Sr3 Lu( PO4 ) 3:Pr3+phosphor was successfully synthesized by the high-temperature solid-phase method.The crystal structure , surface morphology and photoluminescence spectra of Sr 3 Lu( PO4 ) 3:Pr3+phosphor were investigated by X-ray diffraction ( XRD ) , scanning electron microscopy ( SEM ) and spectroscopic techniques , respectively .The research results show that the synthesis of Sr 3 Lu ( PO4 ) 3:Pr3+has a cubic I43d space group structure , and the surface of particles is irregular .The strongest photoluminescent wavelength is 444 nm, and the strongest emission wavelength is 610 nm.The emission light is red .When the doping concentration is 1 mol;, the sample has the best luminous effect .

Effect of Temperature on Output Characteristics of CIGS Solar Cells

LIU Fang-fang;WANG He;ZHANG Yi;ZHOU Zhi-qiang

2017, 46(9):  1762-1766. 

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The temperature characteristic is an important feature of the solar cell , in this paper we report on the output characteristics of Cu ( In, Ga) Se2 ( CIGS) thin film solar cell changing with temperature (120-260 K).The study reveals that with the increasing temperature , the open circuit voltage of Voc lowers obviously with the temperature coefficient of -1.08 mV/K, while the short circuit current Isc rises slightly with the temperature coefficient of 0.01401 mA/K.This is mainly because with temperature rising, the band gap decreases and dark current increases , resulting in drop of Voc , more photogenerated carriers are stimulated and series resistance drops , resulting in the increase of Isc .With combined effects of these two aspects , the conversion efficiency decreases .

Piezoelectrical and Dielectrical Properties of CeO2 Doped KNN-LiNbO3 Based Lead-free Piezoceramics

LI Zhen-yu;GAN Guo-you;XU Teng-wei;GUO Gen-sheng;DU Jing-hong;ZHANG Jia-min;YAN Ji-kang;YI Jian-hong

2017, 46(9):  1767-1772. 

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Ternary system piezoelectric ceramic materiais 0.98K0.5 Na0.5 NbO3-0.02LiNbO3 -xCeO2 (0. 98KNN-0.02LN+xCeO2 ) were fabricated using solid state sintered technology .The effects of additive contents ranging from 0.00 to 4mol; on structural characteristics and electrical properties of 0.98K0.5 Na0.5 NbO3-0.02LiNbO3 lead-free piezoelectric ceramics doped with CeO 2 were investigated.The crystal structure of the ceramics changes from orthorhombic phase to tetragonal phase when content of CeO 2 change from x =0.00 to x =0.01 and x =0.02 to x =0.04, and the coexistence of orthorhombic-tetragonal phases are observed when x=0.00 and x=0.02.The results show that when adding a small amount of CeO 2 , it show the characteristics of the acceptor doping and when adding amount of CeO 2 , results show the characteristics of the sintering additives .The optimization comprehensive property was at the addition of 2mol;CeO2 sinter temperature 1080℃.The main parameters for the composition of x=0.02 are:d33 =104 pC/N, Qm =2201, kp =0.24423,εr =804.2, tanδ=8.748;.

Electronic Structure of Monolayer MoS2 with Yttrium, Zirconium and Niobium Doping

LIU Yuan-quan

2017, 46(9):  1773-1777. 

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Band structure and density of states of yttrium ,zirconium and niobium doped single-layer MoS 2 are studied by first principles method .It is found that the bond length of impurity atoms is distorted by yttrium, zirconium and niobium doped monolayer MoS 2 in the Molybdenum position , but the distortion rate of yttrium doped system is the largest .Through the study of yttrium , zirconium and niobium co-doped system, that we can get the conductive property of monolayer MoS 2 was improved by yttrium ,zirconium co-doping;the yttrium and niobium co-doped sites are easy to be the electron trapping centers the reason for the Fermi energy passes through the impurity levels and the energy level is half full .There are many impurity levels in the band gap in zirconium and niobium co-doped system , as well as conduction band energy move to high energy region .Electronic structure of monolayer MoS 2 were changed in the co-doped systems.

First-principles Study on Electronic Structure and Optical Properties of Zn-doped Wurtzite CdSe

WANG Fei-yu;ZENG Ti-xian;AN Xin-You;YANG Hui;ZHANG Min;CHEN Tai-hong;SONG Ting-ting

2017, 46(9):  1778-1785. 

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Band structures , density of states and optical properties of different concentration of Zn atom dopping wurtzite Cd 1 -x Zn x Se are calculated and studied with plane-wave ultrasoft pseudopotential method based on first-principles density functional theory .After full relaxation , the calculations show that the volume of Cd1-xZnxSe increases, the formation energy of Cd1-xZnxSe reduces and the stability of Cd1 -x Znx Se become stronger with the increasing Zn impurity concentration .The Zn doping leads to the conduction band shift from low-energy area to high-energy area , and also band gaps of doped systems become wider .Zn-Se bond shows strong interaction , the Mulliken overpopulation is bigger , more covalent bonding character .The changing of gap induced blue shift of the optical transition peak .In the ultraviolet area around 9.75 eV, the absorption of doping system strength achieve its greatest and least energy loss .

Structure and Magnetic Properties of Ba(NiMg)0.2AlxFe11.4-xO19 Prepared by Sol-gel Auto-combustion Method

CHANG Jing-yu;KONG Di;MA Zhen-zhen;LIU Xian-song;LI Ming-ling

2017, 46(9):  1786-1790. 

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The Ni, Mg, Al co-doped M-type barium ferrite powders (Ba(NiMg)0.2AlxFe11.4-xO19, x=0-0.4 ) were prepared via a sol-gel auto-combustion method using citric acid as complexing agent .The structure and room-temperature magnetic properties of the as-samples were studied by X-ray diffraction ( XRD) , transmission electron microscope ( TEM) and physical property measurement system ( PPMS) . The results show that the phase constitutent of the samples is closely related to the amount of Al doping . When the x value exceeds 0.2, the impurity alpha-Fe2O3 appears in the products, and the content of alpha-Fe2 O3 increases with the increase of the amount of Al substitution .The saturation magnetization (10 kOe) decreases with the increase of x value, while the coercivity (Hc) value increases first and then decreases with the increase of x value, and the coercivity reaches the maximum value of 5644 Oe at x=0.2, corresponding to the saturation magnetization of 46 emu/g.

Effect of Mg Doping on Electronic Structure and Electrical Properties of CaMnO3 Thermoelectric Oxide

CHEN Xiang;REN Yi-xin;ZHANG Fei-peng;YANG Huan;ZHANG Jiu-xing;ZHANG Xin

2017, 46(9):  1791-1797. 

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The electronic structure , density of states and charge populations of the Mg doped CaMnO 3 oxide for Ca site has been studied by the psudo-potential density funtional theory calculation method , the electrical properties of the doped oxide have been analyzed thereafter .The calculational results show that the Mg doped CaMnO3 oxide has indirect band gap yet , the band gap has been slightly decreased from 0. 756 eV to 0.734 eV.The peak value of density of states curves locates at -0.8 eV for the pure CaMnO3 oxide and the Mg doped CaMnO 3 oxide .The Mn contributes less to density of states at Fermi level , however the O atom and the Ca atom contribute more to density of states at Fermi level .The Mg has stronger capability of releasing electrons into the system than that of the Ca , it should belong to electron carrier doping type for the Mg doping for Ca for the CaMnO 3 oxide system .The Mg doping for Ca should enhance the electrical conduction capablity for the CaMnO 3 oxide , the electrical property should be strengthed .

Solverthermal Preparation of C3N4-CaTi2O4(OH)2 Powder and Its Photocatalytic Properties

DONG Wei-xia;BAO Qi-fu;YAN Chang-qing;QIU Bo-xin;ZHANG Si-si

2017, 46(9):  1798-1802. 

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C3 N4-CaTi2 O4 ( OH) 2 composite powders were prepared by the addition of a certain molar ratio of C3 N4 powder using anhydrous calcium chloride-TBOT-anhydrous ethanol system by solvothermal method.The microstructure of the samples were characterized by X-ray diffraction ( XRD ) , specific surface area ( BET ) and scanning electron microscopy ( SEM ) .And the absorption properties of the samples were analyzed by ultraviolet-visible absorption spectrophotometer .Effects of different C 3 N4 composite on phase , microstructure and photocatalytic properties of CaTi 2 O4 ( OH ) 2 samples were studied.The experimental results show that: the introduction of C 3 N4 powder significantly enhance the photocatalytic activity of CaTi 2 O4 ( OH ) 2 samples and the sample has the highest photocatalytic performance(K=0.02338 min-1) in 250 nm when CaTi2O4(OH)2:C3N4 composite molar ratio is 1:0.75.

Electromagnetic Properties of Mn-doped Half-metallic Ferromagnet Fe2 Si Calculated by First-principles

LI Rui-jie;YANG Yin-ye;CEN Wei-fu;LYU Lin;XIE Quan

2017, 46(9):  1803-1808. 

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The electronic structure and magnetic properties of Mn-doped Fe2-x Mnx Si systems have been calculated by the first-principles pseudo-potential method based on density functional theory ( DFT) .The results show that the Mn-doped Fe2-x Mnx Si system is a ferromagnet with different ratios of Mn , the half-metallic gap of undoped Fe2Si is 0.164 eV.When the doping ratio is 8.3;, the spin-down part is transformed into the direct bandgap semiconductors of L .The Fe2-x MnxSi (x=0.17) system exhibits half-metallic properties .When the doping ratio is 12 .5;, the spin-down part is transformed into the direct bandgap semiconductor of A, and the Fe2-x MnxSi (x =0.25) system exhibits half-metallic properties .The system is transformed into metal when the doping ratio is 25;.Mn-doped makes the band structure and electron density of Fe 2-x Mnx Si systems move in the low energy direction , and the Fermi level falls into the spin-down band gap , which makes the spin polarization rate reach 100;.The half-metallic and magnetic properties of Fe 2-x Mn x Si systems are mainly derived from the d-d exchange between Fe-3d and Mn-3d electrons, p-d hybridization between Si-3p and Fe-3d electrons.The results provide effective theoretical guidance for the electromagnetic control of half-metallic ferromagnet Fe 2 Si.

Corrosion Resistance of Al2O3/Ni Composite Coating Prepared on Mg Alloy Surface

FAN Ye-li;WANG Wei

2017, 46(9):  1809-1813. 

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Al2 O3/Ni composite coating was deposited on AZ 91D Mg alloy in two different proportions by electrophoretic deposition technique in order to improve the corrosion resistance of Mg alloy , and after dried for 12 h in a dry container , vacuum sintering densification process at 300 ℃ for 4 h is following. Surface morphology , compositions and microstructures of the coating were investigated using scanning electron microscopy(SEM), energy dispersive spectrometer (EDS) and X-ray diffraction(XRD) as well. Corrosion resistances of the coating were evaluated in 3.5wt; NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS).The result showed that compared to the pure Al2O3 coating, the porosity of Al2O3/Ni composite coating decreases due to the addition of Ni , and the mismatch of thermal expansion coefficient of the coating and Mg alloy is reduced , and the bonding strength is enhanced .In the coatings of four different ratios , the composite coating with a mass ratio of Al2 O3 and Ni is 1:3.The surface of the composite coating more smooth and compact , and the corrosion resistance properties of the coating is better .

Research on Photocatalytic Process Mechanism of Polyacrylonitrile Modified Titanium Dioxide

ZHANG Jie

2017, 46(9):  1814-1817. 

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The mechanism of photocatalytic degradation of TiO 2 was explored by adding hole inhibitors ( EDTA) , free radical inhibitors ( t-BuOH ) in the process of degradation of methyl orange .From our experiment can be found that the main oxidative species is holes in the photocatalytic process could be detected through the trapping experiments of radicals and holes .Because conductive polymer PAN will be able to separate electron-hole timely, reducing the chance of electron-hole recombination , the photocatalytic activity of the composite particle is significantly higher than that of pure TiO 2 .

Study of Antioxidants Variation of Gradient SiC Coating on SiCf/SiC Composites

HUO Yan-li;CUI Yan-ling;LIU Hai-lin;HU Chuan-qi;HUANG Xiao-ting;CHEN Yu-feng;TANG Jie

2017, 46(9):  1818-1822. 

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SiC f/SiC composite material with low density , stability at elevated temperature , oxidation resistance , high corrosion resistance and other characteristics , has huge potential in use of the space and structure of aero engine components and nuclear fusion reactor first wall structure .At present , limited by process conditions , the atom ratio of C to Si is more than 1.3, and there are pore and defects in the SiC f/SiC composite .So that it can't meet the service requirements of high temperature oxidation environment . In this paper, a graded coating with a high purity , low defect, high temperature resistant , anti-oxidation, low hypoxia diffusion coefficient and good matching with substrate , had been prepared by chemical vapor deposition ( CVD) on the surface of SiC/SiC composite material .And SEM was used to observe the microstructure of coating and the binding properties on coating and SiC /SiC substrate .XRD was used to characterize the component of the gradient coating and the changes of component when the coating was oxidized.And then the gradient coating anti-oxidant mechanism was discussed .

Study on Influence Factors of Hardness of Electroformed Gold

ZHENG Li-shan;YUAN Xin-qiang;LEI Ting;WANG Cheng-bo

2017, 46(9):  1823-1827. 

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Gold electrodeposits were studied by X-ray spectrometer , scanning electron microscope and microhardness tester .Results show that different samples have different Vickers hardness .By comparing grain size , the texture coefficient of the same crystal face , and Vickers hardness , it is found that abnormal hardness appeared when grain size of plating was in the nanocrystalline region , and the Hall-Petch rule wasn't suitable to analyze realationship between grain size and hardness .Gold plating has higher Vickers hardness when has stronger ( 111 ) preferred orientation .The highest Vickers hardness of eight plating samples can reach to 117 HV0.2.The maximum texture coefficient can be reached to 70. 59;.Stronger (111) preferred orientation may weaken surface roughness .By means of adding additives in electrodeposition technique , preferred orientation of plating could be controlled , and electrodeposits with higher hardness and smooth surface would be got .

In-situ Synthesis and Properties of Mullite by Different Silicon-source

HU Qi-guo;GU Xing-yong;DONG Wei-xia;LUO Ting

2017, 46(9):  1828-1832. 

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Mullite samples were in-situ synthesized by solid state reaction using coal gangue , fly ash, yellow sand, Suzhou clay as a silicon-source, industrial aluminum hydroxide as aluminum-source and AlF3 with V2 O5 as additives.The phase structure and microstructure of the samples were analyzed by X-ray diffraction and scanning electron microscopy .The characteristics of the samples prepared under different silicon-source and their structural changes were studied .The results show that mullite crystal phase with acicular morphology is synthesized by using Suzhou clay as a silicon-source , and a columnar morphology of mullite and flaky morphology of alumina crystal phase can be obtained by using coal gangue and yellow sand as a silicon-source respectively , and the main crystal phase with fly ash as the silicon-source was columnar mullite .The bulk density , porosity and flexural strength of the samples prepared from different silicon-source were studied respectively , and the formation mechanism of mullite was discussed .

Synthesis of LDHs Magnetic Composites and Visible-Light Photocatalytic Activity

WANG Wei-wei;YU Huan;YAO Jia-liang;ZHANG Ai-juan

2017, 46(9):  1833-1837. 

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The interaction among units favors the separation of the photogenerated electron /hole pairs, which is an effect method to improve its photocatalytic performance .Layered double hydroxides ( LDHs) sheets grew vertically on the surface of Fe 3 O4 introducing Cu , which exhibited good visible-light photocalytic property .The morphology , particle size , crystallinity , magnetic property and compositions were characterized by X-ray diffraction, scanning electron microscopic analysis , X-ray photoelectron spectroscopy , infrared spectrum and alternating gradient magnetometer .The photocalytic property of the single materials, the mixture of Fe3 O4 and Cu-Mg-Al-LDHs powders, and Fe3 O4/Cu-Mg-Al-LDHs were investigated.The experimental results show that Fe 3 O4/Cu-Mg-Al-LDHs composites exhibited better visible-light photocalytic property in the degradation of methyl orange .In addition , Fe3 O4/Cu-Mg-Al-LDHs composites can be separated by applying an appropriate magnetic field .

Effect of PVA on the Structure and Optical Properties of ZnO Nanorods

WU Ke-yue;CAI Sheng-wen

2017, 46(9):  1838-1841. 

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ZnO nanorods were prepared from zinc nitrate hexahydrate and PVA by hydrothermal method . The characterizations of ZnO nanorods were carried out by X-ray diffraction ( XRD ) and scan electron microscope (SEM).Absorption of nanorods was measured by UV-Vis spectra.The results show that the ZnO nanostructures are rod-like crystal of hexagonal wurtzite structure .The length of ZnO nanorods increase from 400 nm to 2 μm with increasing the PVA concentrations .The absorption spectra show that the optical band gap red shift with increase PVA concentration .

Preparation of Ag3 PO4/ZnO Composite Powder and Its Visible-light Photocatalytic Performances

GAO Ya;WEN Yu-ting;LU Xue-quan;SI Sheng-yu;HAN Cheng-liang

2017, 46(9):  1842-1845. 

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Using ZnO powders , Na2 HPO4 , AgNO3 and polyvinylpyrrolidone as raw materials , Ag3 PO4/ZnO composite powders were successfully prepared at room temperature .The phase structure , morphology and adsorption of visible-light of composites with various ratios of ZnO and Ag 3 PO4 were characterized by X ray diffraction, scanning electron microscopy and UV spectrometer .The photocatalytic activity of corresponding Ag 3 PO4/ZnO composite powders was also investigated . The results show that the performance of photocatalytic degradation of rhodamine B is excellent ( the degradation rate is 99;or so ) when the molar ratio of ZnO and Ag 3 PO4 is about 1:1.

High Stoichiometric-ratio SnS2 Thin Films Rapid Prepared by Spin Coating-pyrolysis Method in Air

ZHANG Zheng-guo;WANG Kai;WU Shan-shan;SUN Zhi-an;GONG Bo-lin

2017, 46(9):  1846-1850. 

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To prepare high stoichiometric-ratio SnS2 thin films rapidly, a facial spin coating-pyrolysis method was introduced and a serials SnS 2 thin films were prepared at 200 ℃, 260 ℃and 320 ℃in air using SnCl4 · 5H2 O and thiourea.To the best of our knowledge , the spin coating-pyrolysis method was the first time using to prepare SnS 2 thin films.Energy spectrum analysis ( EDS ) , X-ray diffraction ( XRD) , Raman scattering analysis , scanning electron microscopy ( SEM) and ultraviolet-visible spectro photometer ( UV-Vis ) were used to investigate the elementary compositions , crystalline phases , morphology and optical absorption of SnS 2 thin films. The SnS2 thin film with the high Sn/S stoichiometric-ratio of 1/1.98 and a direct corresponding ban gap of 2.50 eV was prepared at 260℃just for 2 min, which was very suitable for the window layer in thin film solar cells .

Property Characterization of Ionic Liquid Modifying Silica

WANG Bing-hui;XIONG Yu-zhu;WU Sheng-xue;JIANG Meng;WANG Qian;ZHANG Qing-po

2017, 46(9):  1851-1857. 

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Ionic liquid 1-allgl-3-methylimidazolium chloride ( AMI ) was employed to modify silica .The microstructure and property of silica of modification before and after were characterized with Fourier transform infrared spectroscopy ( FT-IR ) , X-ray diffraction ( XRD ) , X-ray photoelectron spectroscopy ( XPS ) , Thermal gravimetric analysis ( TGA ) , Scanning electron microscope ( SEM ) , contact goniometer, BET specific surface area and pore diameter analysis .The result shows that , through AMI modification, interaction of silica particle decrease obviously , agglomeration between the particles weak , dispersion property improve evidently in rubber composite matrix , hydrophobic property of modified silica enhance, the range of contact angle increase from 12.7°to 80.5°.Specific surface area aggrandize from 67.84 cm2/g to 124.28 cm2/g.Modification before and after, the crytalline structure of silica change little, yet amorphous structure .

Research on Preparation of Light-weight and High-intensity Ceramsites with Shangluo Vanadium Tailings

ZHAO Wei;WANG Bin-yu;ZHOU Chun-sheng;ZHANG Guo-chun;HAN Xi

2017, 46(9):  1858-1863. 

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The lightweight high-intensity ceramsites were prepared with 80wt; Shangluo vanadium tailings as main raw materials, adding potassium feldspar and clay .SiC powders are used as foaming agent .The influence of vanadium tailings content , SiC content , sintering temperature and holding time on structure and properties of ceramsites was studied , respectively .The results show that the bulk density and compressive strength of ceramsites are reduced with SiC content increasing , sintering temperature enhancing and holding time extending .The light-weight and high-intensity ceramsites are sintered at 1125℃for 30 min with SiC content of 2wt;.The bulk density of the ceramsites is 631 kg/m3 .The compressive strength is 9.1 MPa, and the water absorption is 3.1;.

Research on the Mechanical Properties and Thermal Conductivity of 96 Alumina Ceramics

WU Hai-dong;LIU Wei;CHENG Li-xia;LIU Jian;TAN Yi-cheng;XIANG Qi-jun;WU Shang-hua

2017, 46(9):  1864-1868. 

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The effect of sintering temperature on mechanical property and thermal property of alumina ceramics consolidated by pressureless sintering were investigated .The density , mechanical properties , thermal conductivity , microstructure , and phase composition were analyzed by Archimedes , three point bending , laser pulse method , scanning electron microscope and X-ray diffraction , respectively .The results showed that better thermal property and higher mechanical properties can be obtained at 1600 ℃and the value of thermal conductivity , density, hardness, bending strength are 24.9 W/(m· K), 3.82 g/cm3,(13.8 ±0.2) GPa, (362.9 ±26.9) MPa, respectively.

Effect of Different Forms of Aluminum on SiAlCO Ceramic Coating Prepared by Laser Pyrolisis Polysiloxane

ZHAO Ji-xin;QIAO Yu-lin;XUE Yin-chang;LIANG Xiu-bing

2017, 46(9):  1869-1874. 

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The ceramic coatings were prepared by laser pyrolysis of aluminium-containing polysiloxane . The formation and structure of the product were characterized by scanning electron microscopy (SEM), X-ray diffraction ( XRD) and X-ray photoelectron spectroscopy ( XPS).The results show that the chemical valence of Al has a great influence on the morphology of the ceramic coating prepared by laser pyrolysis of polysiloxane.During the laser pyrolysis process, Al react with the C, O and Si of polysiloxane and generate new ceramic phase .Crystalline Al0.2 Si0.8 O2.2 and amorphous Al2 O3 ceramic phase are generated with the addition of Al particles , while amorphous Al2O3 and AlOx ceramic phase are generated by adding aluminum isopropoxide into the polysiloxane .The new ceramic phase leads to the less porosity of the ceramic coating and makes the coating surface uniform and densified via filling the pores .

Hydrothermal Synthesis ofγ-Bi2 Sn2 O7 and Its Photoelectric Response Research in Visible Light Zone

JIAO Yue-chao;LIU Xian-sheng;QU Bo-yang;ZHANG Peng;YAN Li;ZHU Yong-sheng;FU Kai

2017, 46(9):  1875-1878. 

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Gamma phase (γ) Bi2 Sn2 O7 was synthesized by hydrothermal method and its photoelectric response in visible light was investigated .The structure and photoelectric response properties were characterized by X-ray diffraction and surface photovoltage spectroscopy . The results show the as-prepared Bi2 Sn2 O7 presents a presents a gamma (γ) phase cubic structure and has an optical band gap (2.67 eV) measured by absorption spectrum , which is narrower than that of α-Bi2O3 (2.85 eV).The photoelectric response of Bi 2 Sn2 O7 in visible light area displays its advantage compared with α-Bi2 O3 . Meanwhile , it has strong response under the applied voltage .