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。     

Co_2O_3掺杂Ba(Ti_(0.91)Zr_(0.09))O_3陶瓷介电性能研究

采用固相反应法制备了Co2O3掺杂的Ba(Ti0.91Zr0.09)O3陶瓷,研究了Co2O3掺杂对Ba(Ti0.91Zr0.09)O3陶瓷相结构与介电性能的影响。结果表明,掺杂Co2O3后Ba(Ti0.91Zr0.09)O3陶瓷产生了第二相,随着Co2O3施主掺杂量的增加,抑制了第二相的产生,掺杂后的Ba(Ti0.91Zr0.09)O3陶瓷是具有弥散相变的铁电体,弥散程度随掺杂量的增加而增加,x=0.01时,矫顽场最大。     

Co_(0.5)Zn_(0.5)Fe_2O_4/C复合物的制备及电磁性能研究

采用水热法制备出不同比的Co0.5Zn0.5Fe2O4/C复合物,通过X射线衍射分析仪(XRD)、扫描电镜(SEM)、能谱仪(EDS)、振动样品磁强计(VSM)、网络分析仪对该复合物的形貌、电磁性能进行表征与分析。结果表明:Co0.5Zn0.5Fe2O4被碳包裹程度随碳相对含量的增加而增加;在频率为3~18 GHz范围内,Co0.5Zn0.5Fe2O4/C复合物的介电常数虚部和介电损耗随Co0.5Zn0.5Fe2O4的相对含量增加而增加;与Co0.5Zn0.5Fe2O4相比,Co0.5Zn0.5Fe2O4/C复合物的最大吸收峰有明显提高,且当0.5 g Co0.5Zn0.5Fe2O4与2 g葡萄糖混合时,制备的样品最大吸收峰在频率16 GHz左右可达到7 d B。     

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.     

Optical and Magnetic Properties of Fe_2O_3/SiO_2 Nano-composite Films

Fe2O3/SiO2 nano-composite films were prepared by sol-gel technique combining heat treatment in the range of 100-900 ℃. The particle size was observed by FE-SEM. Optical properties of the films were investigated by UV-visible spectra. Structural and magnetic characteristics were investigated through FT-IR and VSM. The transparency of the Fe2O3/SiO2 nano-composite films decreased with the content of the Fe2O3. Water and organic solvent in the films were evaporated with heat treatment, so the transparency of the films was enhanced under high temperature. It is also found that the saturation magnetization (Ms) of the films increases with the temperature. As the content of the Fe2O3 increases, when the content of the Fe2O3 is around 30wt%, the Ms of the films has a maximum value.     

Dielectric and Magnetic Properties of (1-x)CaTiO_3-xNi_(0.5)Zn_(0.5)Fe_2O_4 Composite Ceramics

(1-x)CaTiO_3-xNi_(0.5)Zn_(0.5)Fe_2O_4(0 x 1.0) composite ceramics were synthesized by a conventional solid state reaction method.The phase formation,microstructure,and dielectric and magnetic properties were investigated by X-ray diffraction,scanning electron microscopy,precision impedance analysis,and vibrating sample magnetometry,respectively.The results indicate that the composite ceramics are composed of both perovskite phase Ca TiO_3 and spinel phase Ni_(0.5)Zn_(0.5)Fe_2O_4.The maximal relative density for 0.5CaTiO_3-xNi_(0.5)Zn_(0.5)Fe_2O_4 composite ceramics reaches 97.8%,as it has been sintered at the temperature of 1260 ℃ for 3 h.Dielectric constant and loss tangent of(1-x)CaTiO_3-xNi_(0.5)Zn_(0.5)Fe_2O_4 composite ceramics show dispersion in the low frequency range.Their phase transition temperature of the dielectric constant shifts to lower temperatures with the increase of Ni_(0.5)Zn_(0.5)Fe_2O_4 content.This phenomenon is attributed to that the phase transition temperature of CaTiO_3 is higher than that of Ni_(0.5)Zn_(0.5)Fe_2O_4.The saturation magnetization of (1-x)CaTiO_3-xNi_(0.5)Zn_(0.5)Fe_2O_4 composite ceramics increases with the Ni_(0.5)Zn_(0.5)Fe_2O_4 ferrite content.     

溶胶-凝胶法制备纳米Fe3O4/SiO2复合粒子

采用溶胶-凝胶法,以正硅酸四乙酯作为表面修饰剂,对Fe3O4纳米粒子的表面进行包覆,制备出了磁性Fe3O4/S iO2纳米复合粒子.通过TEM,XRD,IR表征,复合粒子的粒径在15 nm~20 nm左右,呈球形且分散较均匀.     

用(NH_4)_3PO_4辅助还原的Sr_3Al_2O_6:Eu的发光特性

用(NH4)3PO4作辅助还原剂,在炭热还原气氛中制备的Sr3Al2O6:Eu,在360nm左右的紫外光激发下,仅有二价铕离子发出黄绿色荧光,与二价铕离子激活的其它发光材料不同,用250nm左右的紫外光激发时,能同时观察到二价铕离子和三价铕离子的特征发射光谱.     

Fe_3O_4/SiO_2复合粒子的制备及对Cd~(2+)的吸附性能研究

采用共沉淀法制备出粒径为10nm左右、具有超顺磁性的Fe3O4纳米粒子,在Fe3O4纳米粒子外包覆SiO2合成了磁性Fe3O4/SiO2复合粒子,研究了该复合粒子对水溶液中Cd2+离子的吸附性能.利用透射电子显微镜(TEM)、X射线衍射仪(XRD)、红外光谱(FTIR)、振动样品磁强计(VSM)和原子吸收分光光度计(AAS)对样品进行表征,考察了SiO2不同包覆量对吸附剂吸附性能的影响.结果表明:随着SiO2包覆量的增大,SiO2壳层厚度增大,内核中包埋的Fe3O4粒子数量增多,Fe3O4/SiO2复合粒子尺寸随着增大,由50nm左右增大到300 nm左右;Fe3O4纳米粒子表现出了良好的磁性能,比饱和磁化强度达73.6A·m2·kg-1,Fe3O4/SiO2复合粒子的比饱和磁化强度随SiO2包覆量的增大而逐渐减小;Fe3O4/SiO2复合粒子的吸附率随着SiO2包覆量的增多而逐渐增大,最大吸附率为91.0%.     

掺Bi2O3,B2O3,V2O5和B2CuO4对Sm(Mg1/2Ti1/2)O3性质及显微结构的影响

实验添加多种助烧结剂于以固态反应法制备的钐镁钛微波介电陶瓷Sm(Mg1/2Ti1/2)O3,并研究对烧结体的相对密度、相变化、介电常数、频率温度系数(TCF)、品质因子及微观结构性质的影响。尝试分别加入10 mol%的Bi2O3、B2O3、V2O5及B2CuO4可有效降低陶瓷孔隙率使其致密化,更可大幅下降块材烧结温度,使之可以顺利导入低温共烧陶瓷制程(Low-Temperature Co-fired Ceramics;LTCC),但会破坏钙钛矿晶体结构,引起材料微波特性降低。在实验中原料混合粉末以1 100℃煅烧2 h后研磨,再成型后以1 300℃烧结6 h。结果显示以添加Bi2O3具有最高的密度及Q×f与介电常数,达6.47 g/cm3和26 000 GHz及30.19。     

静电纺丝技术制备Eu(BA)3phen/PVP复合纳米带及发光性质研究

采用静电纺丝技术合成了Eu(BA)3phen/PVP复合纳米带,用扫描电镜,红外光谱,紫外-可见吸收光谱和荧光光谱对样品进行了表征。扫描电镜分析表明,纳米带表面光滑,宽度为1-6μm,平均厚度为230 nm。红外光谱分析表明,Eu3+与配体发生键合,在430 cm-1出现了Eu3+-O2-特征振动峰。紫外-可见吸收光谱分析表明,Eu(BA)3phen/PVP复合纳米带的吸收带与纯Eu(BA)3phen配合物相比,发生了红移。激发光谱分析表明,Eu(BA)3phen/PVP复合纳米带在210-360nm之间有较宽的吸收带,最大吸收波长位于275 nm。发射光谱分析表明,在275 nm紫外光激发下,Eu(BA)3phen/PVP复合纳米带的发射主峰为位于617 nm的红光,属于Eu3+的5D0→7F2跃迁。电偶极跃迁与磁偶极跃迁强度的比值约为2.8,表明配合物中Eu3+位置的对称性较低,不存在反演中心。     

两种芬顿及UV/草酸铁/H2O2法去除间甲酚的研究

研究了UV／草酸铁／H2O2，UV／芬顿和暗芬顿系统中K2C2O4，H2O2，FeSO4浓度，pH值，反应温度，反应时间以及光照条件对间甲酚去除的影响，得出VU／草酸铁／H2O2系统比其他两种系统对间甲酚具有更高的去除率，且使去除反应进行pH范围更宽，并可缩短反应时间。同时证明，自然光照条件下UV／草酸铁／H2O2和UV／芬顿工艺对间甲酚仍有较高的去除率。     

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％。     

Fe3O4/黄腐酸复合材料的制备及其对Cu2+吸附性能研究

采用化学共沉淀法合成了一种黄腐酸(Fulvic acid,FA)包覆型磁性复合材料(Fe3O4/FA)。扫描电镜(SEM),粉末X射线衍射(XRD)和傅里叶变换红外光谱(FT-IR)测试表明合成产物颗粒大小约2μm,具有典型的反尖晶石结构,黄腐酸成功包覆在Fe3O4颗粒表面。Fe3O4/FA在外界低磁场作用下两分钟内便可从水溶液分离。Fe3O4/FA对Cu2+的吸附是一个假二级动力学过程,在1h左右达到平衡,较好的符合Langmuir吸附模型.在pH=7时最大吸附量可以达到9.38mg/g,和Fe3O4相比其对Cu2+的吸附能力显著增强。Fe3O4/FA可以作为一种有效去除重金属污染废水中Cu2+的吸附材料。     

Influence of annealing time on the microstructure and properties of Pb(Zr0.53Ti0.47)O3 thin films

The PZT thin films were prepared on (111)- Pt/Ti/SiO2/Si substrates by sol-gel method, and lead acetate [Pb(CH3COO)2], zirconium nitrate [Zr(NO3)4] were used as raw materials. The X-ray diffractometer (XRD) and scanning electron microscopy (SEM) were used to characterize the phase structure and surface morphology of the films annealed at 650 ℃ but with different holding time. Ferroelectric and dielectric properties of the films were measured by the ferroelectric tester and the precision impedance analyzer, respectively. The PZT thin films were constructed with epoxy resin as a composite structure, and the damping properties of the composite were tested by dynamic mechanical analyzer (DMA). The results show that the films annealed for 90 minutes present a dense and compact crystal arrangement on the surface; moreover, the films also achieve their best electric quality. At the same time, the largest damping loss factor of the composite constructed with the 90 mins-annealed film shows peak value of 0.9, higher than the pure epoxy resin.     

水溶液中Fe_2(SO_4)_3与KI反应的研究

研究了不同温度下水溶液中Fe2（SO4）3与KI（Na2S2O3,淀粉）的反应速率．在15－29℃范围内,Fe2（SO4）3与KI（Na2S2O3,淀粉）的反应速率比相同条件下的Fe（NO3）3反应体系慢3-4倍．使用721-分光光度计测定了水溶液中Fe（Ⅲ）与SO42-离子形成配合物的配位比．结果表明,在PH=1．5及21℃时,存在Fe2（SO4）3的二聚体Fe4（SO4）6。     

KF/Al2O3催化下2-甲基-3-(3,4-亚甲二氧基苯基)丙烯醛的合成研究

对KF／Al2O3催化洋茉莉醛和丙醛进行Claisen-Schmidt缩合反应2－甲基－3－（3，4－亚甲二氧基苯基）丙烯醛进行了研究，结果表明KF／Al2O3是较好的催化剂，通过正交实验确定了适宜的工艺条件：洋茉莉醛：丙醛为0．3：0．42（摩尔比），14g催化剂，丙醛滴加时间2h，反应温度60－70℃，反应时间2h，平均摩尔收率为80．2％。     

Fabrication and characterization of SiO2（f）/Si3N4 composites

A silicon dioxide fiber-reinforced silicon nitride matrix (SiO2/Si3N4) composite used for radomes was prepared by chemi- cal vapor infiltration (CVI) process using the SiCl4-NH3-H2 system. The effects of the process conditions, including infiltration tem- perature, infiltration time, and gas flux were investigated. The energy dispersion spectra (EDS) result showed that the main elements of this composite contained Si, N, and O. The X-ray diffraction (XRD) results indicated that phases of the composite before and after treatment at 1350°C were all amorphous. A little fiber pull-out was observed on the cross section of the composite by scan electron microscope (SEM). As a result, the composite exhibited good thermal stability, but an appropriate interface was necessary between the fiber and the matrix.     

Co(Hdpa)3(ClO4)2的合成及其在不同溶剂中的光谱性质

研究合成配合物Co（Hdpa）3（ClO4）：（Hdpa=2,2’-二吡啶胺）,并测定配合物在甲醇、甲苯、乙醇、乙腈、N,N-二甲基甲酰胺和二甲亚砜等6种溶剂中的紫外光谱和荧光光谱性质．结果表明,配合物的电子吸收光谱和发射光谱的最大峰位置与强度在不同溶剂中有很大差异,主要是由各种溶剂的极性（介电常数）和施主性质（施主数）不同引起的．     

Fe2(SO4)3对活性污泥微生物活性的影响

为了解Fe₂(SO₄)₃作为絮凝剂对活性污泥中微生物活性的影响,向活性污泥系统中投加质量浓度为20、40、60、80,100 mg·L-1的Fe₂(SO₄)₃,反应4 h后测定活性污泥的脱氢酶活性、比耗氧速率(R_SOU)、胞外聚合物(EPS)及各组分含量,同时测定系统出水的COD等各项指标．结果表明:Fe₂(SO₄)₃质量浓度在20～60 mg·L-1时对活性污泥的脱氢酶活性、R_SOUEPS及各组分含量影响均不大,此时污水中COD、TP、UV₂₅₄等污染物随Fe₂(SO₄)₃质量浓度增加而有较大幅度去除．Fe₂(SO₄)₃质量浓度为80 mg·L-1时,污泥的脱氢酶活性、R_SOU、总EPS含量均明显下降．当Fe₂(SO₄)₃质量浓度增加到100 mg·L-1时,污泥的脱氢酶活性、R_SOU进一步受到抑制,而总EPS含量则大幅度提升．此时污水中COD、TP、UV₂₅₄等污染物去除率增加幅度变缓,SCOD及NH₃-N去除作用有所下降．