Table of Content

15 July 2017, Volume 46 Issue 7

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Synthesis, Structure Characterization and Optical Property of Nonlinear Optical Crystal δ-LiZnPO4

JIAO Zhi-wei;WANG Hai-jun;ZHU Guang-wei;SUN Tong-qing;CUI Yan;LIU Feng-bin;QU Min

2017, 46(7):  1197-1202. 

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Crystalline characteristic of δ-LiZnPO4 was studied under using LiF as flux system.Transparent eutectic crystallization of δ-LiZnPO4 and Li4Zn(PO4)2 with size of 1-3 mm was obtained by spontaneous crystallization method.Eutectic phase composition was determined via X-ray diffraction and element analysis, and structure of δ-LiZnPO4 crystal separated from the eutectic crystal was analyzed.The results show that the δ-LiZnPO4 crystals have a non-centerosymmetrical structure, belong to the orthogonal crystal system, space group Pna21 with lattice parameter a=1.00085 nm, b=0.93900 nm, c=0.66545 nm, Z=4.Structure analysis confirms that the crystal consists of PO4, ZnO4 and LiO4 tetrahedron to form a zeolite structure type of ABW.The transparent pure phase δ-LiZnPO4 single crystal with size of about 10 μm was also synthesized by hydrothermal method.Powder second harmonic generation (SHG) tests show that the powder SHG effect of δ-LiZnPO4 crystal is about 1.7 times of KDP and the ultraviolet(UV) cut-off wavelength of δ-LiZnPO4 crystal is 218 nm, which indicate that δ-LiZnPO4 crystal is a promising nonlinear optical crystal in the UV region.

Study on the Polycrystalline Synthesis Method for High Purity CdSe Compound

NI You-bao;CHEN Shi-jing;WU Hai-xin;ZHANG Chun-li;HUANG Chang-bao;WANG Zhen-you

2017, 46(7):  1203-1208. 

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CdSe is one of the most important Ⅱ-Ⅵ group semiconductors, it is widely used in the nuclear radiation detection, nonlinear frequency conversion and so on.As the foundation for achieving these applications, the polycrystals act as the base for the growth of high quality CdSe single crystals.However, the traditional synthesis methods have shortcomings of one kind or another, for instance the lower yield or purity.Hence, a modified synthesis method was introduced, with the aid of numerical simulation, by lowering the pressure difference on the inner and outer crucible, about 200 g CdSe polycrystals could be obtained in one run.The XRD, TG/DTA, ICP methods were used to characterize the synthetic materials, the test results show the prepared materials are high purity and suitable for single crystals growth.The effects on the purity of polycrystals probably exist in the synthesis process are also discussed in the paper.

Fabrication and Properties of Porous Mullite Ceramics from Directly Sintering Ceramic Microspheres

LAN Tian;ZHANG Xiao-yan;LI Na;YANG Jin-long;HUANG Yong;WANG Xiu-hui

2017, 46(7):  1209-1214. 

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SiO2-Al2O3 ceramic microspheres were fabricated by particle-stabilized foams method combining with centrifugal spray drying process, where high purified quartz powder, alumina powder and glass powder were chosen as raw materials.Then, SiO2-Al2O3 ceramic microspheres were closely packed in the crucible, followed by directly sintering at 1500 ℃ for 1 h and porous mullite ceramics with well distributed pores were prepared through self-foaming process at elevated temperature.The effect of raw materials compositions on the properties of porous mullite ceramics has been studied.This novel method is simple, convenient, and controllable.Porous mullite ceramics with high porosity of 85.4;, compressive strength of (3.69±0.86) MPa, and low dielectric constant of 1.70 was obtained by this method which could be applied to the wave-transparent materials field.

Measurement of γ Sensitivity and Time Response of the Large Area LaBr3∶Ce Scintillation Detector

HU Meng-chun;LI Zhong-bao;LIU Jian;FU Yue-cheng;ZHANG Fa-qiang;WANG Wen-chuan;ZHANG Jian-hua;TANG Deng-pan;LI Ru-rong;CHEN Li-xiong;HUANG Yan

2017, 46(7):  1215-1219. 

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The γ sensitivity of a large area LaBr3∶Ce scintillation detector was measured in a 60Co standard source field, and was compared with the sensitivities of scintillation detectors which were made up of GD100 photoelectric tube and LYSO∶Ce or ST401 scintillator, the time response waveform of this LaBr3∶Ce scintillator was measured with a nanosecond pulse radiation source.As is shown in the measuring results, the ratio of volume normalized sensitivity of the LaBr3∶Ce scintillator to those of LYSO∶Ce scintillator and ST401 scintillator is bigger than 5 and 200, respectively.The front edge, full width at half maximum (FWHM), back edge and decay time evaluated from the measured time response waveform of the LaBr3∶Ce scintillator are 2.56 ns, 56 ns, 23.56 ns and 25.45 ns, respectively.

Preparation and Thermal Stability of Magnesium Doped Hydroxyapatite Whiskers

ZHANG Hong-quan;LI Xiao-yan;WEN Jin

2017, 46(7):  1220-1226. 

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Hydroxyapatite (HA) is an excellent bone substitute materials.Magnesium doped HA (Mg-HA) whiskers can not noly enhance the biological properties of HA, also be used as reinforcement for biomedical materials.However, incorporation of Mg2+ into HA would change the crystal structure and affect their thermal stability.Thus, Mg-HA whiskers were prepared by a hydrothermal synthesis method, and their crystal structure, thermal stability and the influencing factors of the Mg-HA whiskers were studied by XRD, FTIR and SEM.The results show that the crystallinity of HA decrease with the increase of magnesium ion doping content when the magnesium ion doping content is less than 5;, and the cell parameters a is basically unchanged, and c is gradually reduced.When magnesium ion doping increase to 8;, a small amount of impurity peaks assign as Ca7Mg2P6O24 appear.Mg-HA would decompose at 800 ℃, forming HA/β-TCP bipasic calcium phosphate.Magnesium ion doping content, calcination temperature and bioglass addition are found significantly to enhance the decomposition of HA.

Synthesis and the Gas Sensing Performance of "Sandwich-like" PbS Nanocrystals/rGO Composites towards Ammonia at Room Temperature

ZHAO Yun-feng;WANG Hao-ran;LI Xin-hong;WANG Zi-wei;YANG Shuang;LIU Yue-li

2017, 46(7):  1227-1232. 

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Sandwich-like PbS nanocrystals(NCs)/rGO composites were prepared by one-step solution method.The crystal structure and surface morphology of the samples were characterized by X-ray diffraction and Field emission scanning electron microscopy.The gas sensor was fabricated with external heating to test its gas properties.The results show that PbS NCs are decorated uniformly on the rGO sheet with a 3-D sandwich-like structure in the composites.The composite has good gas sensing properties to NH3 at room temperature.PbS NCs/rGO composites possess a quite good gas response towards ammonia gas, the response of 1000 ppm NH3 is 3.45, which is obviously enhanced compared with pure PbS NCs and rGO.The composite has the detection limit of 1 ppm to NH3 gas with a good selectivity.The gas sensing mechanism shows the rGO in the composite acts as a carrier transport layer while the 3-D structure increases the gas diffusion rate and adsorption area.The composite is expected to be widely used in NH3 detection at room temperature due to its special structure and excellent gas sensing performance.

Effect of Calcining Temperature on Piezoelectric Properties of (Ba0.85Ca0.15)(Ti0.9Hf0.1)O3 Lead-Free Piezoelectric Ceramics

REN Xiang-yun;ZHOU Heng-wei;ZHANG Chao;HUANG Yi-neng;YIN Hong-mei

2017, 46(7):  1233-1238. 

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(Ba0.85Ca0.15)(Ti0.9Hf0.1)O3 (abbreviated as BCHT)lead-free piezoelectric ceramics were prepared successfully using a solid state reaction method.The effects of calcining temperature (1100~1250 ℃) on the microstructure and electrical properties of the BCHT ceramics were investigated.The results indicate that all the samples possess a pure perovskite phase structure.The phase structure of the sample change from tetragonal phase to rhombohedral phase around room temperature with increased calcining temperature, and the rhombohedral phase and tetragonal phase coexist in the composition range of 1150~1250 ℃.Meanwhile, the piezoelectric constant d33, remnant polarization Pr first decrease and then increase,and dielectric constant εr , diffusion coefficient γ first increase and then decrease,the coercive field Ec decreased with increasing the amount of calcining temperature.The comprehensive properties of (Ba0.85Ca0.15)(Ti0.9Hf0.1)O3 exhibits optimum value at 1250 ℃: d33=525 pC/N, Pr=10.2 μC /cm2, Ec=1.30 kV/cm, and εr =17699, γ=1.65, which indicates that the ceramic has a good application prospect.

Research on Wet-etching of AlN Single Crystals Grown by Spontaneous Nucleation

LIU Li-xiang;CAO Kai;WANG Jia;REN Zhong-ming;DENG Kang;WU Liang

2017, 46(7):  1239-1243. 

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AlN single crystals prepared by a novel spontaneous physical vapor transport (PVT) growth approach at 2100-2250 ℃ were etched in molten KOH/NaOH eutectic alloy.All samples were investigated by scanning electron microscope (SEM) after wet-etching, optimal parameters and morphologies for c-plane, r-planes and m-plane of AlN single crystals are obtained.The growth habits and etch pit densities (EPD) of crystals grown by proposed novel spontaneous approach are also revealed.

Preparation and Performance of the Hollow Bauxite Ceramic Proppant

MOU Jun;XUE Qi;DONG Peng-peng;LI Huan;XU Yong-chi

2017, 46(7):  1244-1249. 

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In the present study, the hollow bauxite proppant with controlled inner-hollow structure was prepared by templates method with the urea and MnO2 as well as the bauxite powder used as pore forming template, sintering additives and spherical shell coating material, respectively.The change of the mineral facies composition and chemical component of the raw material before and after vsintering were analysed by X-ray fluorescence, the TG-DSC, XRD and SEM.The SEM was used to observe the variation in microtopography of the ceramic proppant.The influence of pretreatment on the microstructure and properties of the as-received hollow bauxite proppant was investigated,and the influence mechanism is analyzed.The results show that the pretreatment of calcining the raw material powder contributed to improve the strength of proppant.After sinter at 1440 ℃, the main phase constitution of the as-prepared sample is mullite phase and corundum phase.Meanwhile, the volume density of the hollow proppant manufactured by lightly calcined bauxice is 1.35 g·cm-3, the apparent density is 2.47 g·cm-3, the breakage rate is 5.21; at the closure pressure of 25 MPa, and the average value of the compression resistance for single grain is 58 N.The sample quality is stable and the productive process is easily controlled.

Investigation on the Sound Insulation Properties of Non-uniform Local Resonant Phononic Crystals

WANG Yi;GUO Hui;LYU Jiang;WANG Yan-song;LIU Ning-ning

2017, 46(7):  1250-1257. 

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Unit structure model of local resonant phononic crystals is set up.The effects of array configuration, filling rate arrangement and the arrangement of scatterer thickness are studied on the sound insulation properties of non-uniform phononic crystals (NPCs) through the finite element method.So that the structure of NPCs in different frequency bands play a good sound insulation effect and reduce the local attenuation in acoustic band.When the scatterers are close to the incident direction of array configuration, the NPCs have more sound insulation.If the filling rate increases from the middle column to the both sides, the NPCs have less local attenuation.With the scatterer thickness decreasing from the middle column to both sides, the NPCs are suitable for suppressing the medium-high frequency vibration or noise.On the contrary, another arrangement structure, with the scatterer thickness decreasing from the middle column to both sides, is suitable for low frequency noise isolation.The NPCs with the aluminum vibrator, the steel vibrator or the lead vibrator have similar sound insulation properties at low frequency, and the sound frequency band at medium and high frequencies is moved to low frequency with the increase of vibrator density.The obtained results may be provided as a theoretical guidance for the NPCs playing good effect on noise reduction.

Preparation of g-C3N4/kaolinite Composite by Intercalation Method and Its Optical Performance

CHENG Hong-fei;DU Bei-bei;SUN Zhi-ming;LI Chun-quan

2017, 46(7):  1258-1262. 

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The surface and the interlayer of kaolinite has high activity and good normality which is so suitable for chemical modification, hence, the catalyst loading is worthy of in-depth study.Using methoxy-grafted kaolinite as precursor, the kaolinite-melamine composites were prepared by the displacement intercalation method.Then the kaolinite-melamine composite materials was calcined in the 550 ℃ to obtain the g-C3N4/kaolinite composite materials.The prepared composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry and differential scanning calorimetry (TG-DSC), and their photocatalytic performance were also studied.It is indicated that it is difficult to synthesize g-C3N4 when kaolinite-melamine ratios are 1∶1 and 1∶2;while the composites with different ratios of g-C3N4 will be get when the mass ratio of kaolinite and melamine is 1∶3, 1∶4 and 1∶5, respectively.Kaolinite can effectively prevent the reunion of g-C3N4, and improved dispersion condition can be obtained due to the addition of kaolinite.The prepared g-C3N4 /kaolinite composites have good photocatalytic performance which has great significance in the research of mineral based economic, efficient and green catalyst.

Optical Parametric Oscillator Pumped by Acoustic-optic Q-switched with Nd∶YVO4 Composite Crystal

LI Shi-xia;LI Xiao-min;LI Gui-qiu

2017, 46(7):  1263-1266. 

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Using a non-critically phase-matched KTiOPO4 crystal, an optical parametric oscillator was successfully achieved by acoustic-optic Q-switched with Nd∶YVO4/Nd∶YVO4/Nd∶YVO4 composite crystal.Under an incident pump power of 8.29 W and modulation frequency of 30 kHz, the maximum average output power at the signal wavelength of 1570 nm is 0.92 W,the shortest pulse duration is 1.04 ns for the signal wave, the maximal peak power of 29.5 kW.The conversion efficiency to the 1064 nm Q-switched pump beam is 54.4;, to the 808 nm diode pump beam is 11.1;.

Preparation of CMAS Glass-ceramics with Blast Furnace Slag by Sintering

HU Lan;HE Feng;ZHANG Wen-tao;SHI Jiang;PEI Ke-peng;PANG Huan-xin;WANG Li-ge;XIE Jun-lin

2017, 46(7):  1267-1273. 

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Blast furnace slag and other auxiliary chemical reagent were used for basic glasses making.The CaO-MgO-Al2O3-SiO2(CMAS) glass-ceramics were prepared by one-step sintering method.Differential scanning thermal spectrum, X-ray diffraction spectrum and field emission scanning electron microscopy were used to investigate the effect of Heat treatment system on crystallization and properties of CMAS glass-ceramics.The results show that with the increase of heat treatment temperature, the main crystal phases of the glass-ceramics are pyroxene, and the secondary crystal phases are feldspar, the precipitation of crystal phase increases, and the bulk density and flexural strength increase first and then decrease.With the increase of heat treatment time, the bulk density and flexural strength showed a decreasing trend.When the heat treatment temperature is 1020 ℃ and the crystallization time is 30 min, the mechanical properties of the sample are the best, the bulk density is 2.690 g·cm-3 and the flexural strength is 67.00 MPa.

Synthesis and Electrochemical Performance Research of SnO2/Nitrogen Doped Graphene Nanocomposites

ZUO Zhen-min;XIE Zhi-yong;WANG Qian;LIU Bei;LI Xiang-hui;HUANG Qi-zhong

2017, 46(7):  1274-1282. 

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The SnO2/rGO and SnO2/rGO nano-composite was successfully synthesized by in-situ growing SnO2 nano-particles on GO with a mild hydrothermal method, using ammonium hydroxide as pH modifier to realize N doping of graphene, and the cell as well as catalytic performance of the two composites were investigated.The XRD and SEM results show that SnO2 particles disperse homogeneously on the surface of nitrogen doped graphene(N-rGO) and graphene(rGO) layers with the size of 50 nm and 100 nm respectively.Further TEM results indicate that the SnO2 particles are composed of smaller ones whose size range from 5 nm to 7 nm.The main half-cell test results can be concluded as follows, when the current density is 100 mA/g, the reversible capacities of SnO2/N-rGO and SnO2/rGO are 901 mAh/g and 756 mAh/g, respectively, which are 6.0 and 4.9 times higher than those of the pure SnO2 nanoparticles.The discharge capacities of SnO2/N-rGO and SnO2/rGO at 2 A/g are 619 mAh/g and 511 mAh/g, respectively, exhibiting an excellent rate performance.The electrochemical test proves that the catalytic performance for oxygen reduction reaction (ORR) of SnO2/N-rGO is significantly better than that of the SnO2/rGO and both exhibits a nearly four electron transfer process, providing a new direction for the non-platinum catalyst research.

Effect of S Adsorption on Different Reconstructed Structures of SiC Surface

CHAO Miao-miao;YANG Ying

2017, 46(7):  1283-1287. 

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SiC surface reconstruction will cause the increase of surface state densities, which can greatly affect the performance of SiC power devices.This paper aims to investigate the (3×3) R30° and (3×3) reconstructed structures on 4H/6H-SiC (0001)-Si terminal and the (3×2) and (2×1) reconstructed structures on 3C-SiC (0001)-Si terminal after S atoms adsorption.The results show that S adsorption can open the reconstruction bonds and that the different reconstructed structures have a tendency to recover to the ideal models.The optimum adsorption rate of (3×3)R30° is 1/2ML and that of (3×3) is 1/3ML.The adsorbed S atoms have a greater impact on the recovery of the (3×3)R30° reconstructed structure than that of (3×3).Additionally,H3 site is the best initial position and 1/6ML is the optimum adsorption rate for (3×2) 3C-SiC reconstructed structures,while B site is the best initial position and 1/2ML is the optimum adsorption rate for (2×1) 3C-SiC reconstructed structures.The surface adsorption energy of 3C-SiC reconstructed structures is smaller and the surface is more stable than that of 4H/6H-SiC.The recovery of 3C-SiC reconstructed structures is more desirable.

Preparation Processes and Photovoltaic Performance of Perovskite Solar Cells

LI Cheng-hui;ZHENG Hai-song;LIU Jun;XIAO Zhi-ming;ZHAO Yu;WEI Ai-xiang

2017, 46(7):  1288-1293. 

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The perovskite solar cells with structure of glass/FTO/compact TiO2/mesoporous TiO2/CH3NH3PbI3 film/carbon electrode were prepared, and the photovoltaic performance of solar cells was studied.The perovskite CH3NH3PbI3 layers were prepared by two-step method.First, PbI2 thin films were deposited by spin coating method.Second, to grow perovskite layers, PbI2 films were dipped into 0.044 mol/L of MAI/IPA solution for 0.5 h, 2.5 h, 3.5 h and 4.0 h, respectively.The effect of dipping time on structure and morphology of perovskite layers, as well as photovoltaic performance of perovskite solar cells were studied.The results indicate that the full conversion of PbI2 to perovskite carry out and the average grain size of CH3NH3PbI3 is the largest when dipping time is 3.5 h.The perovskite solar cells prepared at dipping time of 3.5 h exhibited an optimal photovoltaic performance, which demonstrate the open circuit voltage of 0.881 V, short-circuit current density of 22.17 mA/cm2, power conversion efficiency of 6.79;, and the efficiently of incident photons converting to the electrons (IPCE) of close to 50; in visible range.

Preparation of Silicon Oxycarbide Porous Ceramics by Silicone Resin

ZHANG Hai-sheng;ZHANG Jun-zhan;ZHANG Ying;HE Hui;WANG Ning

2017, 46(7):  1294-1299. 

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Silicon oxycarbide(Si-O-C) porous ceramics with single component, controllable pore structure and high ceramic yield were prepared at 1200 ℃ in N2 atmosphere by using RSN-6018 silicone resin as preceramic polymer and introducing certain content pre-cured silicone resin.The effects of the contents of pre-cured silicone resin on the microstructure and properties of Si-O-C porous ceramics were studied.Results show that pre-cured silicone resin can adjust the pore morphology, pore diameter and porosity of Si-O-C porous ceramics.When the content of pre-cured silicone resin is lower than 90wt;, the pore structure of Si-O-C porous ceramics changes from the through-hole to the through-pore formed by the overlapping of particles and then to the open pore formed by the accumulation of particles with the increasing of the content of pre-cured silicone resin.At the meanwhile, the porosity increases.However, the shrinkage decreases, whereas ceramic yield increases.The compressive strength of Si-O-C porous ceramics is 27.9-17.5 MPa.

Effect of Composition on Electrochemical Performance of Ce0.8Sm0.2O1.9-BaCe0.8Sm0.2O2.9 Composite Electrolytes

ZHAO Xiao-hui;MOU Xue-ping;XIONG Yue-long;PENG Kai-ping

2017, 46(7):  1300-1306. 

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The composite electrolytes Ce0.8Sm0.2O1.9-BaCe0.8Sm0.2O2.9(SDC-BCS, molar ratio 9∶1, 7∶3, 5∶5 and 3∶7) were synthesized by one-step citric acid-nitrate gel combustion method.In this work, the effect of SDC-BCS composition on the conductivity and electrochemical performance were studied.The results indicate that grain size and electrical conductivity of SDC-BCS increase with increasing of SDC content in SDC-BCS.Compared to electrolyte SDC, the grain-boundary conductivity of composite electrolytes is much higher.The power density of the single cell NiO-SDC-BCS|SDC-BCS|LSCF-SDC-BCS which was prepared by composite electrolytes with different phase compositions increases with increasing SDC content.When the molar ratio of SDC∶ BCS gets 9∶1,the peak power density of the single cell is 550 mW/cm2 at temperature 700 ℃, which is 3 times higher than that of NiO-SDC|SDC|LSCF-SDC single cell.

Study on Sm, C and Sm/C Co-doped Nano-TiO2 and Its Visible Photocatalytic Properties

PENG Fu-chang;ZOU Jian-xin

2017, 46(7):  1307-1314. 

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The nano-TiO2 photocatalysts with element doping by Sm and C were prepared via a facile sol-gel procedure.Samples were characterized by XRD, SEM, TEM, XPS, UV-Vis-DRS, PL and Nano-sizer nano particle size analyzer,etc.The photocatalytic activity of different TiO2 samples were evaluated by photocatalytic degradation of methylene blue (MB) under the irradiation of fluorescent lamp.The results show that single Sm ion doping inhibited the phase transition from anatase to rutile and restrained the increase of grain size, but single C ion doping promote formation of rutile phase.Appropriate doping amount of Sm and/or C broadene the absorption region to visible light, refined grain and decrease the recombination of the photo-generated electrons and holes.Doping of Sm and C improve the photocatalytic activity of TiO2 and there existe synergistic effect in co-doping.The degradation rate of MB over the sample with molar ratio of n(Sm)∶n(C)∶n(Ti)=0.01∶0.3∶1 and sintered at 500 ℃ is the best under the irradiation of fluorescent light, the first-order apparent rate constants increased by about 4.3 times than that of pure TiO2 under the same experimental conditions.

Preparation and Oxygen Permeation Properties of Ce0.8Sm0.2O2-δ-Ca3Co2O6-δ Dual Phase Membrane

CHEN Ting;XIE Zhi-xiang;HU Xiao-bo;ZHANG Xiao-jun;JIANG Wei-hui;JIANG Wan

2017, 46(7):  1315-1321. 

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Ce0.8Sm0.2O2-δ and Ca3Co2O6-δ powders were synthesized via coprecipitation and citrate complex methods, respectively, followed by sintering in air to achieve the dense Ce0.8Sm0.2O2-δ-Ca3Co2O6-δ dual-phase membrane.The phase composition and the microstructure of the samples were studied by X-ray diffraction patterns (XRD) and field emission scanning electron microscopy (FESEM), respectively.The study was carried out on elucidating of the influences of dual phase ratio on the thermal expansion coefficient, electronic conductivity and oxygen permeability of the dual-phase membrane.The experiment results indicate that the two phases exhibit good chemical stability, and the dense membrane is achieved after sintering at 1150 ℃ for 6 h.The membrane shows low thermal expansion coefficient, as 13.47×10-6 ~14.23×10-6 K-1, which is closed to that of the solid electrolyte.Increasing the ionic phase from 40wt; to 80wt;, the electronic conductivity is decrease gradually, while the oxygen permeation flux of the dual-phase membrane is increase significantly.The Ce0.8Sm0.2O2-δ-Ca3Co2O6-δ membrane with the two phases weight ratio of 8∶2 exhibited excellent oxygen permeation performance, as 2.80×10-7 mol·cm-2·s-1 at 950 ℃, indicating it may be a promising candidate for oxygen separation.

Microstructure and Mechanical Properties of Al2O3 Ceramics Prepared by Gelcasting Method

HE Xiu-lan;GUO Xiao-jie;LI Yu-kun;YUE Ming-yue;HAO Yin;GUO Xiao-yu

2017, 46(7):  1322-1326. 

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Al2O3 ceramics were prepared by the gelcasting and pressure-less sintering method, with Al2O3 as starting powder, TiO2+MgO as sintering additives, agarose as the monomer, and ammonium polyacrylate as the dispersing agent.The solidification mechanism of agarose, sintering mechanism of sintering additive and the effect of the agarose content on the microstructure and mechanical properties of green body and sintered body were investigated.The experimental results show that the three-dimensional net structures form by means of abundant hydrogen bonds in the agarose.So the raw Al2O3 powders solidify.The TiO2+MgO sintering additive realize liquid sintering mechanism, so it is beneficial to reduce the sintering temperature and promote densification process.With increasing agarose content, both the flexure strength and relative density of green body and sintered body firstly increase and then decrease.The composite containing 0.5wt; agarose exhibits the highest flexure strength.

Effect of PEG-6000 on Sintering Properties of Mn-Zn Ferrite Nanopowders

SUO Qiang-qiang;HUA Fei;ZHANG Xue-lin;PENG Hui-fen;WANG Xin

2017, 46(7):  1327-1332. 

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In the research, some PEG-6000 was introduced during the preparation of Mn-Zn ferrite nanopowders by chemical co-precipitation and reflexing method, tried to form a protective layer around the Mn-Zn ferrite nanoparticles for the purpose of prohibiting their aggregation.The results proved that addition of PEG-6000 not only decreased size of the nanoparticles, but also effectively alleviated their aggregation.By using those Mn-Zn ferrite nanopowders as starting materials to mould and then sinter at suitable temperatures, it's found that initial permeability of the sintere samples parabolically varied with an increase in temperatures and reach the maximum at the sintering temperature of 1200 ℃.The PEG-6000 added samples presente the initial permeability about 20; higher than those without any PEG-6000.Those results should be attributable to improvement in stability of the nanopowders and homogeneity in microstructure of the sintered samples, together with decrease in their grain size, by PEG-6000.

Effect of Sintering Heating Rate on Barium Titanate Ceramic Piezoelectric Properties

ZHU Qiang;ZHOU Heng-wei;ZHANG Chao;YING Hong-mei

2017, 46(7):  1333-1337. 

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BaTiO3 ceramics were prepared by traditional solid state reaction method at different heating rates and the crystal structure, surface morphology, dielectric, piezoelectric and ferroelectric properties of ceramic samples were tested and analyzed.The results show that when the sintering temperature rate is 3 ℃/min and 5 ℃/min, the ceramic is tetrahedral perovskite lattice structure.With the increase of the heating rate, the tetragonal phase increases while the average grain size decreases, electrical coefficient and the ferroelectric properties decrease with it.However, the dielectric constant increases.When the sintering temperature rate is 5 ℃/min, dielectric constant is the largest with the value of 3144.When the sintering temperature rate is 1 ℃/min, the ceramic is orthorhombic perovskite lattice structure, of which the d33 and Pr is the maximum, its value is Pr =10 μC/cm2 while d33=193 pC/N.

Study on Soft Magnetic Properties of Fe80.8Si7.2B6Nb5Cu Amorphous-nanocrystalline Magnetic Powder Core

ZHANG Zong-yang;LIU Xian-song;ZHANG Cong;LI Hao-hao;MENG Xiang-yu;LIU Chao-cheng

2017, 46(7):  1338-1342. 

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First, Fe80.8Si7.2B6Nb5Cu amorphous strip was prepared by melt spinning method, then after annealing, grinding, molding, annealing and a series of processing, the Fe80.8Si7.2B6Nb5Cu amorphous-nanocrystalline magnetic powder core with compact microstructure was obtained.The basic properties of magnetic powder core, such as micro morphology, magnetic permeability, power loss, quality factor, and so on were studied.The results show that Fe80.8Si7.2B6Nb5Cu amorphous-nanocrystalline duplex magnetic core has high permeability (36-37), and relatively stable in different frequency and magnetic field, and at low frequency (less than 200 kHz), when the magnetic field is less than 50 mT, the maximum power loss is only 49.42 W/kg;futhermore, it has good quality factor.

Theoretical Study on Band Gap Modifying of Chiral BN Nanoribbon by the Stone-Wales Defects and C Doping

XU Xiang-fu;LAI Guo-xia;ZHU Wei-ling;CHEN Xing-yuan

2017, 46(7):  1343-1347. 

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Based on density functional theory, the band gap modulation of chiral BN nanoribbon by Stone-Wales defects and C doping was studied in this paper.The calculated results show that the Valence Band Maximum (VBM) and Conduction Band Minimum (CBM) of BN nanoribbon could be changed by appearance of Stone-Wales defects and the band gap decreases since the defect energy level is introduced, while the number of the Stone-Wales defects has little influence on band gap width.The electronic structure calculations show that the defect energy level of BN nanoribbon with Stone-Wales defect are decided by the N-N atoms π orbital nearby VBM and the B-B atoms σ bond nearby CBM.The impurity energy levels can be further introduced in the BN nanoribbon with Stone-Wales defect by C doping ,which generated by C-C atoms σ bond nearby VBM and C-B atoms σ bond nearby CBM to reduce the band gap of BN nanoribbon and expand its application.

Synthesis and Magnetic Properties of Two One-dimensional Lanthanide Complexes Bridged by Carboxylate Ions

YANG Yan;LEI Quan;SU Gang-ping;GONG Li;WANG Bo;SHE Shi-xiong

2017, 46(7):  1348-1354. 

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Two new carboxylate-bridged 1D chain complexes, e.g.[Ln2(PAA)6]n ((PAA-=4-aminobenzoic acid anion, Ln=Tb(1),Ho(2)), have been synthesized under solvothermal conditions and characterized by single crystal X-ray crystallography analysis, FT-IR,TG-DTA and elemental analysis.Results show that both complexes are isostructural 1D chains and bridged by carboxylate groups.Magnetic susceptibility of polycrystalline samples of complex 1 were carried out ousing a SQUID magnetometer.The magnetic studies indicate that complex 1 exhibits slow magnetic relaxation behavior.

Synthesis, Crystal Structure and UV Absorption of Four Coordination Compounds with 2-Methyl-Acrylic Acid 4-(Pyridin-4-ylazo)-Phenyl Ester as Ligand

XU Ling-yun

2017, 46(7):  1355-1360. 

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Four coordination compounds,[Zn(Maape)2(H2O)2(NO3)2] (1, mononuclear), [Cu(Maape)2(H2O)2(NO3)2] (2, mononuclear), [Zn(Maape)2Cl2] (3, mononuclear), [Zn(Maape)(H2O)4SO4] (4, mononuclear) were synthesized with transition metal salts and the ligand (2-Methyl-acrylic acid 4-(pyridin-4-ylazo)-phenyl ester, Maape).The structures of all these compounds were determined by single crystal X-ray diffraction and structural analysis reveals that compounds 1-4 are mononuclear complexes.They were characterized by FT-IR and elemental analysis.The structural construction of these compounds is affected not only by the metal centers but also by the different counteranions.The structure of compounds 1 and 2 is similar which is mononuclear composed of a metal center, two anions and two ligands.Compound 3 is a mononuclear compound which contain a metal ion Zn(II), two chloride coanions and two Maape ligands in the asymmetric units in 3.And the asymmetric unit of compound 4 consists of a discrete mononuclear [Zn(Maape)(H2O)4SO4] molecule with the zinc atom locating at the two-fold symmetric axle.The ligand and its four complexes have the same UV absorption peak at 323 nm.

Friction Properties of Carbon Nano Onions as Lubricating Oil Additives

JIA Jia;ZHANG Wei-ke;JIAO Chen;YANG Hong-yan

2017, 46(7):  1361-1366. 

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Carbon nano onions (CNOs) were prepared by chemical vapor deposition (CVD).The outer layer was graphite layer, which contained Fe-Ni catalyst particles, and the shape was similar to spherical and played the role of "micro-bearing" in mechanical lubrication.The friction performance of the lubricant additive was investigated by rotating oxygen bomb method, four-ball friction tester and lubricating oil anti-wear tester.The results show that carbon nano onions have good anti-wear performance.When the mass fraction of CNOs is 0.05;, the abrasion resistance of lubricating oil is improved obviously.At this time, the extreme pressure value is increased by 64;, the diameter of grinding spot is reduced by 78;, and the oxidation stability is better.

Mechanical Properties of Zirconia Coating Deposited by Solution Precursor Plasma Spraying

CHEN Li-jia;WANG Yi;HAO Shan-peng;SUO Hong-li;LI Huai-zhou;JIA Qiang;LU Dong-qi;HE Ding-yong

2017, 46(7):  1367-1371. 

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Thermal barrier coatings (TBCs) were produced by solution precursor plasma spraying(SPPS) that used aqueous solution of zirconium and yttrium salt as raw materials.The failure of thermal barrier coatings involves many factors.Furthermore, the mechanical properties of ceramics are related to these factors.The mechanical properties of the sprayed coatings were characterized by SEM, XRD and Hardness Tester.The Young's modulus and microhardness of the segmented coating were measured to be about 58 GPa and 7 GPa, relatively higher than 15; with those of the traditional coating respectively.The fracture toughness is 1.8-2 MPa·m1/2 and tensile strength is 25 MPa by an indentation technique.The lower porosity and better lamellar bonding of the segmented coating could be responsible for the improvement of the mechanical properties.

Hydrothermal Synthesis of Whitlockite

LI Guo-chang;LI Si-mao;HUANG Ying-zi

2017, 46(7):  1372-1374. 

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The whitlockite crystals were successfully deposited from the hydrothermal system with CaO, Mg(NO3)2 and H3PO4 at 180 ℃ within 2-4 h.According to the XRD analysis and SEM observation, it is showed that the sample consists mainly of monocrystal spherical aggregates of 5-15 μm in size, the XRD patterns and FTIR spectra were in agreement with the synthetic whitlockite (Ca19Mg2H2[PO4]14).

Synthesis and Formation Mechanism of SnSe2 Nanodisks by Hydrothermal Method

YANG Jun-song;MAO Shu-ling;ZHANG Sheng-yi

2017, 46(7):  1375-1378. 

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SnSe2 nanodisks were synthesized in a hydrothermal system at 180 ℃ using SeO2 as selenium source, SnCl2·2H2O as tin source, N2H4·H2O as reductant.A series of analytic instruments, such as X-ray powder diffraction (XRD) and scanning electron microscope (SEM) , were used to reveal the characterization of SnSe2 nanodisks.The formation mechanism of SnSe2 nanodisks was researched, and the influence of mole ratio and reaction temperature was discussed.

Fabrication of ZnO-SiO2 and Its Photocatalytic Degradation of Rhodamine B

HAO Yan-yan;ZHANG Ying;ZHAO Lin

2017, 46(7):  1379-1384. 

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ZnO-SiO2 composite photocatalysts were prepared by a facile sol-gel process.The effect of heating rate and deposition process on structure, morphology and photocatalytic activity of ZnO-SiO2 was studied.Products were characterized by X-ray diffraction, N2 adsorption-desorption techniques, scanning electron microscopy, UV-Vis diffuse reflectance spectra and photoluminescence.Rhodamine B was used as model dye to evaluate the photocatalytic activity of ZnO-SiO2 composite photocatalysts.The results show that the heating rate has greatly impact on photocatalytic activity of ZnO-SiO2.Scanning electron microscopy images show uniform deposition of zinc oxide nanoparticles on the surface of silica spheres.When the weight ratio of ZnO to SiO2 is 1∶1, the highest photodegradation rate is found.

Crystal Structure and Luminescence of Zinc Coordination Polymer Based on Pyrazinyl Pyridine Ligand

SONG Juan;YANG Shou-jie;REN Chuan-qing;SHI Juan;GE Hong-guang;JIANG Min

2017, 46(7):  1385-1388. 

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A zinc coordination polymer, [Zn(dpb)(p-bdc)]n·0.5n(dpb) has been hydrothermally synthesized by reaction of zinc chloride with 2,6-di(pyrazin-2-yl)-4,4'-bipyridine and p-H2bdc ligands.The coordination polymer was structurally characterized by elemental analyses, IR, and TGA.X-ray single crystal diffraction analysis shows that the coordination polymer is a one-dimension chain structure.Additionally, the fluorescence of free dpb ligand and zinc coordination polymer were also investigated.

Preparation of High Purity Zeolite ZSM-5 from Coal Fly Ash by Two-step Method

KANG Yu-hong;LI Jian;HAO Hua-rui;WANG Ai-min;YAN Long

2017, 46(7):  1389-1393. 

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High purity zeolite ZSM-5 was synthesized by two-step method with coal fly ash pretreated by alkaline fusion and centrifugal extraction and hydrothermal method, the effects of alkali/ash and roasting temperature on the quantity of silicon aluminium dissolution were discussed, the influences of alkalinity, crystallization time, crystallization temperature and the Si/Al ratio on synthesis of zeolites were investigated.The results show that the highest silicon aluminium dissolution quantity obtained at 680 ℃, alkali/ash=2.3 and the high purity ZSM-5 zeolite synthesized at SiO2/Na2O=7, SiO2/Al2O3=45, crystallization time of 68 h and crystallization temperature of 180 ℃.

F-127 as Template for the Synthesis of Micro-Mesoporous SAPO-11 Zeolite and Its Application in Long-chain Alkane Isomerization

WANG Shi-wen;WEI Min;SUN Na;WANG Hai-yan;SHI Yan;WANG Tong

2017, 46(7):  1394-1399. 

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On the basis of the normal hydrothermal synthesis of SAPO-11,an appropriate amount of F-127 was introduced as the soft template to construct the mesoporous structure.The SAPO-11 molecular sieve with meso-microporous composite structure was successfully synthesized.The effects of F-127 addition on the inner pore structure of molecular sieves were investigated.And the catalysts were characterized by X-ray diffraction (XRD),N2 adsorption-desorption curves,scanning electron microscopy(SEM) and pyridine adsorption infrared spectroscopy (Py-FTIR).The results show that along with the increasing addition of F-127, the mesoporous pores of the molecular sieve increase first and then decreaseand the mesoporous structure is produced in the molecular sieve.The isomerization reaction shows that the catalyst activity is related to the mesoporous capacity of the zeolite The conversion rate of alkane rises with the increase of temperature, and the yield of isomer is decreasing.The isomerization conversion rate of the catalyst decreases with the addition of F-127, and the increase of F-127 content in a certain range could lead to the improvement the yield of isomerization.When the addition amount of F-127 is 10;, the yield of isoparaffin reache 57.62;.

Fabrication of Hydroxyapatite/Activated Carbon Composites Adsorbents and Its Absorption Property for Fluoride

LIN Hao;HU Jia-peng;MU Ji-lin;RAO Rui-ye;LIU Rui-lai;WU Dai-she

2017, 46(7):  1400-1407. 

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Hydroxyapatite/activated carbon (HAP/AC) composites adsorbents were fabricated by blend with hydroxyapatite and activated carbon following activation and calcination.The effects of the HAP/AC mass ratio, polyvinyl acetate concentration, calcination time and temperature on adsorption efficiency were investigated.The results show that the optimal conditions were happened in HAP/AC (mass ratio) 4∶1, PVA concentration 3wt;, calcination temperature 350 ℃ and calcination time 3.5 h, producing fluoride adsorption efficiency to 70.69;.The adsorption property of HAP/AC adsorbents toward simulative fluoride waste water by static adsorption and dynamic column adsorption were investigated, moreover the mechanism of the adsorption process was determined.The results show that the fitness of adsorption data by Langmuir model is superior to Freundlich model.Surface monolayer adsorption are dominated in the adsorption of fluoride, and active center with ion-exchange capacity play a leading role in adsorption process.At last, field studies were carried out with the fluoride containing water sample collected from a fluoride-endemic area in order to test the suitability of the adsorbents at field conditions.

Preparation Process of Ni-TiN Composite Coating by Ultrasonic Assisted Pulsed Electrodeposition Method

YUE Wen-xi

2017, 46(7):  1408-1410. 

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Ni-TiN composite coatings were prepared by ultrasound-assisted electrodepositing method on 45# streel.The composite coating was detected by XRD diffraction.And the 3-dimensional surface topography of the composite coatings were observed and analyzed by using atomic force microscopy (AFM) and transmission electron microscopy (TEM).The result indicate that the diffraction peak intensity of Ni-TiN nano composite coating is the highest, and the Ni and TiN phases are significantly refined when the ultrasonic power is 300 W.The distribution of TiN nanoparticles is uniform, and there is no significant aggregation in the coating.

A Method to Measure Parallelism of CdTe Crystal Using Precision Goniometer

JIANG Li-xia;SHANG Ji-fang;LI Qing-lian

2017, 46(7):  1411-1414. 

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The CdTe crystals were processed optically and the parallelism was measured by using two precision goniometers with measurement accuracy of 1″ and a optical flat with parallelism better than 1″, the measured parallelism was compared with that of CaF2 crystal which was processed together with CdTe crystals.The parallelism of CaF2 crystal was measured by a laser plane interferometer.Additionally, the source and magnitude of error in this method were analyzed.The results show that the difference of the parallelism of CdTe and CaF2 is less than 3″.The error mainly come from the measurement error of precision goniometer and the parallelism error of optical flat, and the total error is no more than 5″,which can meet the precision require of parallelism measurement for CdTe crystal.

Effects of Yb3+ Concentration on the Thermal Stability and SpectroscopicProperties of Thulium Doped Tellurite Glasses

WU Teng-yan;ZHONG Hong-bin;PENG Hong-xia;HU Ji-lin

2017, 46(7):  1415-1420. 

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70.75TeO2-19ZnO-9.5La2O3-0.75Tm2O3-xYb2O3 was prepared by high temperature melt cooling method.Differential scanning calorimetry was used to analyze the stability of the glass samples, and all samples had good thermal stability according to the results.UV-Visible-Near infrared spectrophotometer was used to measure the absorption spectrum, Judd-Ofelt strength paranmeters, spontaneous emission probability A, fluorescence branching ratio β and radiative lifetimes τR spectral parameters were calculated by using Judd-Ofelt theory.Results show that when the Yb3+-doped concentration reaches to 0.625mol;, the Tm3+ ions has the longest lifetime of 3H4 which is 0.443 ms, and it is possible to be a promising matrix material for S-band broadband optical fiber amplifier.

Friction Properties of Water-based Cutting Fluid for Crystal Wafer Cutting

XIN Ling;YANG Hui;ZHANG Sheng-mao;YANG Zheng-hong;SUN Yi

2017, 46(7):  1421-1424. 

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Influence factors of the friction performance of the lubricating agent in the water-based cutting fluid for crystal wafer cutting were mainly studied.The low molecular weight polyethylene glycol (PEG) was used as the lubricant, and the tribological properties of PEG with different molecular weight were analysized.In the case of using PEG300 as a water-based cutting fluid lubricant, it is possible to reduce the roughness of the surface of the wafer by more than 86.51; compared with pure water;the wear volume can be reduced by 50; and the wear surface of the worn surface is reduced