TiO_2/ZnO/Ni_(0.5)Zn_(0.5)Fe_2O_4磁载光催化剂的制备及其光催化性能

采用均匀沉淀法制备了镍锌铁氧体、纳米TiO2-ZnO复合粉体和镍锌铁氧体负载纳米TiO2-ZnO复合粉体,并用XRD对所制粉体进行了表征。发现所制得的纳米TiO2为锐钛矿型、镍锌铁氧体为尖晶石型。以甲基橙溶液为模拟废水,考察了纳米TiO2-ZnO复合粉体和镍锌铁氧体负载纳米TiO2-ZnO复合粉体的光催化活性。研究还发现镍锌铁氧体负载纳米TiO2-ZnO粉体后仍具有良好的磁性能,可通过增加外磁场进行分离。     

静电纺丝法制备微孔Mn2O3微/纳米纤维及纤维结构表征

以聚乙烯吡咯烷酮(PVP)为络合剂与醋酸锰Mn(CH3COO)2]反应制得前驱体溶液,用静电纺丝法制备了PVP/Mn(CH3COO)2纤维,经煅烧得到具有微孔结构的Mn2O3微/纳米纤维.对所制备纤维的结晶度、纯度和表面形貌,分别采用差热-热重分析(TGDTA)、红外光谱分析(IR)、X射线衍射(XRD)分析、扫描电镜(SEM)等手段进行了表征.结果表明:煅烧前后纤维的结晶度和形貌发生很大变化.     

PVP/(NH_4)_2Ce(NO_3)_6复合纳米纤维的制备与表征

用静电纺丝技术成功制备了纺丝液中铈浓度为0.1mol/L的有机-无机复合纳米纤维PVP/(NH4)2Ce(NO3)6,并优化了制备工艺。实验结果表明,复合纳米纤维随着铈含量的增大单位长度上的电压值升高,推进设备的推进速度降低;静电纺丝液中加入一定浓度的乙酸,将溶胶凝胶体系的pH控制在1.5～2.5可以明显提高纺丝液的可纺性。复合纤维的平均直径随着铈浓度的提高而增大:铈浓度为0.005mol/L时纤维平均直径为366nm,铈浓度为0.1mol/L时纤维平均直径为415nm;XRD结果表明复合纤维中铈盐为非结晶态。紫外可见分光光度仪检测结果显示,PVP/(NH4)2Ce(NO3)6静电纺丝制得的纳米纤维薄膜具有较好的可见光透过性与较强的紫外光吸收性能。     

(Na_(0.5)K_(0.5))NbO_3基无铅压电陶瓷压电常数的研究

针对目前无铅压电陶瓷的压电常数d33偏小的情况,采用传统的烧结方法制备了(Na0.5K0.5)NbO3基无铅压电陶瓷(Na0.5K0.45Li0.05)Nb0.95-xSbxTa0.05O3(x=0.03,0.06,0.09,0.12),研究了在Li和Ta含量固定的情况下,Sb元素的添加量和烧结温度对陶瓷的压电常数的影响.研究结果表明,适量Sb元素的掺杂可以大幅度提高陶瓷的压电常数d33,陶瓷样品的压电常数d33随着Sb含量的增加先增大后减小.烧结温度可以影响陶瓷的密度,进而影响其压电常数.在1130℃的最佳烧结温度下,Sb含量x=0.09时,陶瓷样品表现出最佳的压电性能,压电常数d33=328 pC/N.     

溶胶-凝胶法制备 Ni0.5Zn0.5Fe2O4纳米材料特性的研究

利用溶胶．凝聚法制备了Ni0.5Zn0.5Fe2O4粉末材料,烧结温度范围600℃-950℃。对材料的结构、红外、磁学和微波吸收特性进行了研究。材料的XRD图谱和原子力显微镜形貌观察表明,材料在纳米尺度范围之内。在500cm-1--600cm-1波数范围内,材料具有明显的红外吸收特性。材料的晶粒尺寸随着烧结温度的提高而增加,且较高温度烧结的材料具有相对低的矫顽力和饱和磁场。利用反射衰减实验研究材料在6GHz--10GHz波段范围的吸波特性,结果表明,0．33mm厚度的样品在常温下的反射衰减达到1．8dBm。     

Ferroelectric properties of Bi_4Zr_(0.5)Ti_(2.5)O_(12) thin films prepared on LaNiO_3 bottom electrode by sol-gel method

The Bi4Zr0.5Ti2.5O12 (BZT) thin films were fabricated on the LaNiO3 bottom electrode using sol-gel method. The structure and morphology of the films were character-ized using X-ray diffraction, AFM and SEM. The results show that the films have a perovskite phase and dense microstructure. The 2Pr and 2Vc of the Pt/BZT/LaNiO3 capacitor are 28.2 μC/cm2 and 14.7 V respectively at an applied voltage of 25 V. After the switching of 1×1010 cycles, the Pr value decreases to 87% of its pre-fatigue val-ues. The dielectric constant (ε) and the dissipation factor (tanδ) of the BZT thin films are about 204 and 0.029 at 1 kHz, respectively. The films show good insulating behavior according to the test of leakage current. The clockwise C-V hysteresis curve observed shows that the Pt/BZT/LaNiO3 structure has a memory effect be-cause of the BZT film’s ferroelectric polarization.     

Y3Al5O12：Ce^3＋发光纳米纤维的制备

采用静电纺丝技术制备了PVP/[Y（NO3）3＋Ce（NO3）3＋Al（NO3）3]复合纳米纤维,对其进行焙烧,得到了结构新颖的Y3Al5O12：Ce^3＋（简称为YAG：Ce^3＋）纳米纤维。XRD分析表明,PVP/[Y（NO3）3＋Ce（NO3）3＋Al（NO3）3]复合纳米纤维为非晶态,经900℃焙烧8h,获得单相石榴石型的YAG：Ce^3＋纳米纤维,属于立方晶系,空间群为Ia3d。SEM分析表明,PVP/[Y（NO3）3＋Ce（NO3）3＋Al（NO3）3]复合纳米纤维表面光滑,直径为210-300nm;YAG：Ce^3＋纳米纤维直径为90~125nm,长度大于100μm。荧光光谱分析表明,在460nm蓝光激发下,YAG：Ce^3＋纳米纤维发射出波长为525nm的黄光,属于Ce^3＋的5D0→7F1跃迁。     

(Li_(0.5)Fe_(0.5))_(0.7-y)Zn_(0.3)C_(oy)Fe_2O_4铁氧体磁性的研究

在Li－Zn铁氧体（Li0.5Fe0.5）0.7ZnFe2O4基础上,用Co2 离子代换其中的（Li Fe3 ）0.5离子,研究了（Li0.5Fe0．5）0.7－yZn0.3CoyFe2O4（y＝0．00;0．005;0．01;0．02;0．03）铁氧体磁性与Co2 离子代换换量y之间的关系,结果表明：随着Co2 离子代换量的增大,晶格常数增大,而气隙率及居里温度减小,当代换量y＜0．005时,饱和磁性极化强度增大。     

TiO_2/NiO复合纳米纤维制备及光催化性能研究

通过溶胶-凝胶过程,采用静电纺丝技术,以聚乙烯吡咯烷酮（PVP,Mn=900 000）和钛酸正丁酯为前驱物,制备了PVP/Ti（OPr）4/Ni（CH3COO）2复合一维纳米纤维材料。经控温缓慢氧化分解,在600℃的条件下成功制备了直径50～100 nmTiO2/NiO纳米纤维。采用扫描电镜、红外光谱、X射线粉末衍射、拉曼等分析手段对样品进行了表征,系统地介绍了TiO2光催化作用机理并在紫外灯下使用样品对罗丹明B溶液进行降解实验。结果显示,0.5%TiO/NiO复合纳米纤维具有良好的光催化活性。     

Synthesis and Piezoelectric Properties of Lead-free (Bi_(0.5)Na_ (0.5))_ 1-x(Ba_aSr_b)_xTiO_3 Ceramics

planarelectromechanicalcouplingfactor;piezoelectricchargeconstant1Introduction Leadoxide basedpiezoelectricceramics,suchasPb(Ti,Zr)O3(PZT),arenowwidelyusedinvariousappli cationssuchastransducers,filters,oscillatorsandactua torsbecauseoftheirsuperiorpiezoe…     

后处理对电纺氧化钛复合纤维表面形貌的影响

以聚乙烯吡咯烷酮的乙醇溶液与钛酸正丁酯为前驱体溶液,采用静电纺丝法制备氧化钛复合纤维,经空气中水解聚合、浸水和煅烧等后处理分别得到表面粗糙的氧化钛复合纤维和氧化钛无机纤维;采用扫描电子显微镜(SEM)、红外光谱仪(FTIR)、热重分析仪(TG)对所制得纤维的表面形貌、结构和组成进行表征.结果表明:初纺的氧化钛复合纤维经过与空气中水分进行水解聚合后,纤维内部形成了不溶于水的骨架结构,使其浸水后仍能保持纤维形貌;同时复合纤维中水溶性成分的去除,使纤维表面形成粗糙结构,这种纤维的表面粗糙结构可通过不同温度煅烧进行调节,同时煅烧后得到氧化钛无机纤维.     

Microstructures and Electrical Properties of Bi_(0.5)-(Na_(1-x-y)K_xLi_y)_(0.5)TiO_3 Lead-free Piezoelectric Ceramics

The microstructures and electrical properties of Bi0.5(Na1-x-yKxLiy)0.5TiO3 lead-free piezoelectric ceramics were studied.These ceramics were prepared by conventional ceramic technique.XRD analysis reveals that the ceramics possess almost pure perovskite phase when y≤0.2.The SEM results show that,with more amounts of Li+,the crystalline grain growing speed is accelerated,and the sintering temperature can effectively be decreased.The measurements of piezoelectric properties indicate that the ceramics with relatively low amount of Li+ and high amount of K+ have comparatively large piezoelectricity.The dielectric measurements show that the ceramics have properties like relaxor ferroelectrics and diffuse phase transition(DPT) at Td and Tc,respectively.The results of ferroelectric measurements reveal the system has relatively higher remanent polarization Pr(27.6 μC/cm2) and lower coercive field Ec(37.5 kV/cm).     

Synthesis and Piezoelectric Properties of Lead-free （ Bi0.5 Na0.5 ）1-x（BaaSrb）xTiO3 Ceramics

A new group of lead-free piezoelectric ceramics,（Bi0.5 Na0.5）1-x（BaaSrb）xTiO3（abbreviated as BNBST[100x-100a/100b],0〈x〈1,a＋b=1）,was synthesized.The ceramics were prepared by conventional ceramic sintering technique,and the ceramics with density of 95% of the theoretical one can be sintered without the atmosphere control during the sintering process.The results of the X-ray diffraction（XRD） data show that the ceramics possess a single perovskite phase.The measurements of dielectric and piezoelectric properties reveal that the ceramics provide relatively high piezoelectric charge constant d33 and high planar electromechanical coupling factor kp.For the BNBST6-95/5 ceramics,d33 is equal to 170pC/N,and kp is equal to 32.0%.The fabrication technique for these ceramics is conventional and stable.     

La0.5Sr0.5CoO3薄膜的制备及其湿敏性质的研究

利用脉冲激光沉积(PLD)的方法,在SiO2/Si衬底成功制备了钙钛矿结构的La0.5Sr0.5CoO3薄膜.对制备的薄膜生长的薄膜进行了XRD测量分析,并且对薄膜的表面形貌进行了测量分析.着重对薄膜的电阻进行了测量,发现环境气氛对电阻的影响,进而对薄膜湿敏电阻进行了测量.     

Oriented Growth of PZT thick film embedded with PZT nanoparticles

This paper reports that dense and crack-free(100)oriented lead zirconate titanate(Pb(Zr0.52Ti0.48)O3,PZT)thick film embedded with PZT nanoparticles has been successfully fabricated on Pt/Cr/SiO2/Si substrate by using PT transition layer and PVP additive.The thick film possesses single-phase perovskite structure and perfectly(100)oriented.The(100)orientation degree of the PZT films strongly depended on annealing time and for the 4 μm-thick PZT film which was annealed at 700 ℃ for 5 min is the largest.The(100)orientation degree of the PZT thick film gradually strengthen along with the thickness of film decreasing.The 3 μm-thick PZT thick film which was annealed at 700 ℃ for 5 min has the strongest(100)orientation degree,which is 82.3%.     

Na_(0.5)K_(0.5)NbO_3织构化陶瓷制备与表征

采用凝固法制备出各向异性的片状钛酸钡作为模板,利用模板晶粒生长(TGG)法制备出Na0.5K0.5NbO3(NKN)织构化陶瓷.研究了NKN织构化陶瓷的工艺、组织和性能.研究结果表明,钛酸钡可以作为NKN陶瓷的模板,在陶瓷烧结过程中诱导NKN晶粒的生长,模板的取向决定了NKN陶瓷晶粒取向,随着烧结温度的升高陶瓷的压电性能(d33)达到69 pC/N,在合理的烧结工艺下得到了取向比较明显的织构化陶瓷.     

Structure of Pb(Zr,Ti)O_3(PZT) for Power Ultrasonic Transducer

To improve the performance of ultrasonic transducer, the samples of PZT were improved by doping. The doped PZT was observed and analyzed from the following aspects: the crystal phase structures, the surface morphologies and the dielectric constant. According to the transducer parameter requirements for ultrasonic machining, there are also requirements for the parameters of piezoelectric ceramics. The high performance PZT was prepared by doping the elements of Ga, Ba, Nb, Sn, and Sr in PZT. The doped PZT is suitable for power ultrasonic machining at 20 kHz through analysis using X-ray diffraction(XPD), a scanning electron microscope(SEM) and LCR meter. Therefore, the excellent performance of transducer for power ultrasonic machining is guaranteed.     

SYNTHESIS AND X-RAY POWDER DIFFRACTION DATA OF A NEW COMPOUND:K_6FeNb_(15)O_(42)

A new compound K_6FeNb_(15)O_(42) was prepared for the first time by solid state reaction in K_2O Fe_2O_3-Nb_2O_5 ternary system. The X-ray powder diffraction data of the title compound was measured. K_6FeNb_(15) O_(42) crystallizes in the hexagonal system with unit cell parameters a=9.1320(4)(?),c=12.0670(9)(?), and space group P63/mcm(193), z=1. The calculated and mea sured densities are 4.489 g/cm~3 and 4.485 g.cm~3, respec tively.     

NiO-TiO2纳米纤维的制备及对模拟印染废水的太阳光催化降解

采用溶胶—凝胶法和静电纺丝法以钛酸四正丁酯（Ti（OC4H9）4）、硫酸镍和聚乙烯吡咯烷酮（PVP）等为主要原料制备了PVP/NiO-TiO2纤维和直径为100～300纳米的NiO-TiO2纳米纤维.以差热—热重分析（DSC-TGA）、傅里叶红外光谱（FT-IR）和扫描电镜（SEM）等对NiO-TiO2纳米纤维进行了表征,测定了其对模拟印染废水亚甲基蓝溶液的太阳光催化性能.结果表明,太阳光照射下,当NiO的掺杂摩尔分数为0.05％,制备NiO-TiO2纳米纤维的焙烧温度为500℃时,NiO-TiO2纳米纤维对亚甲基蓝的催化活性最高,6h降解率达到98.2％,重复使用13次后亚甲基蓝的降解率仍然在93％以上.     

SO4^2-／ZrO2／Al2O3催化剂的制备及其催化性能

用微波、红外、烘箱3种干燥方法制备了负载型纳米ZrO2／Al2O3复合载体,同时在复合载体表面负载SO4^2-制成SO4^2-／ZrO2／Al2O3催化剂,将此催化剂用于α-蒎烯催化异构化反应中。用XRD、FT—IR、TPD等对催化剂的表面积、孔径、晶相结构、酸强度等进行了表征。结果表明,微波干燥法制备的复合载体催化剂（SO4^2-／ZA-W）中ZrO2的粒度较小（平均6nm）,比表面积为156．1m^2／g,平均孔径为4．95nm,其表面酸性中心数和酸强度均高于红外干燥法和烘箱干燥法制备的催化剂。SO4^2-／ZA-W催化剂在α-蒎烯催化异化反应中具有较高的活性,α-蒎烯转化率为95．6％,α-松油烯、柠檬烯等单环萜烯的含量达到56．5％。