高相对分子质量环氧树脂的合成

合成了一种高相对分子质量环氧树脂，并用红外光谱表征了各步产物的结构．研究表明：在第一步反应过程中，随着反应的进行酸值先迅速下降．在40～50min达到稳定，生成了链端带有羧基的线性树脂；第二步反应过程中环氧值快速下降．50～60min时达到稳定，生成链中含有活性基团的环氧树脂b；第三步是环氧树脂b经双酚A扩链，经2h左右的反应后达到稳定，生成相对分子量在10000～20000的高相对分子量的具有高度柔顺性和一定亲水性的环氧树脂．     

TiAl自蔓延高温合成反应的机理

用燃烧波淬熄法研究了大颗粒Ti粉和A1粉制备TiAl金属间化合物的自蔓延高温合成反应机理．通过电镜观察和能谱分析发现：反应过程可用毛细铺展-界面反应机制解释．熔融的A1在整个反应过程中起着主要作用，首先熔融的A1液通过Ti粉间的毛细管作用以薄膜的形式铺展在Ti粉表面，并在接触面生成TiAl3．反应放出的热量有利于加速反应的进行，促使TiAl3与Ti进一步反应生成TiAl,但是生成的TiAl3层阻碍了A1液与Ti粉的接触，制约了反应的进行．最后，在试样中可以同时看到完全反应的Ti粉和未完全反应的Ti粉．     

高相对分子质量环氧树脂的合成

合成了一种高相对分子质量环氧树脂,并用红外光谱表征了各步产物的结构.研究表明:在第一步反应过程中,随着反应的进行酸值先迅速下降,在40～50 min达到稳定,生成了链端带有羧基的线性树脂;第二步反应过程中环氧值快速下降,50～60 min时达到稳定,生成链中含有活性基团的环氧树脂b;第三步是环氧树脂b经双酚A扩链,经2 h左右的反应后达到稳定,生成相对分子量在10 000～20 000的高相对分子量的具有高度柔顺性和一定亲水性的环氧树脂.     

PX氧化过程中Mn催化剂沉淀机理研究

对二甲苯(PX)高温液相催化氧化过程采用Co—Mn—Br三元催化体系，在一定条件下，反应过程中催化剂Mn会形成氧化物沉淀析出，从而影响反应过程及产品质量，对反应产物中灰黑色沉淀固体用X射线衍射法(XRD)进行了表征，验证该沉淀主要成分是MnO1.88的晶体；用原子吸光光度法(ASS)测定了母液中钴、锰离子浓度，从而定量反应过程中Mn的沉淀量，对水浓度、原料PX浓度、Br浓度和锰浓度4种影响Mn沉淀因素进行了系统的实验考察，并结合PX氧化反应机理认识到Mn的沉淀机理为在有水条件下Mn(Ⅲ)发生歧化反应生成MnO2。     

容错控制在香料反应中的研究

针对化学反应器中一类典型反应过程一庚烷生成甲苯，提出了一种关于传感器故障的非线性集成故障诊断与容错控制方策略。经过分析过程的故障类型，建立反应的数学模型，提出了故障的诊断与容错控制算法，并对香料反应过程进行了仿真，实验结果表明该方法是可行。     

甲基丙烯酸十二酯的合成

采用直接酯化法合成了甲基丙烯酸十二酯,反应过程采用全封闭装置,不断移走反应过程中生成的水,使反应化学平衡不断向右移动,产率在９９．０％以上,反应中过量的甲基丙烯酸可以回收利用,基本上实现了工艺无废化。     

石蜡催化氧化反应热效应分析

将石蜡与微晶蜡按质量比为4∶1进行混合共100 g,添加催化剂、助剂,在反应温度、空气流量、反应时间一定的条件下进行氧化反应。反应热效应的分析表明,空气流量和反应温度对反应过程中生成自由基所需的最高能量以及活化能的影响较大。空气流量在4 L/min,温度在170℃时,反应过程中生成自由基所需的最高能量较小,活化能较小,反应容易进行。添加的催化剂和助剂质量对自由基生成的难易程度影响较大,催化剂质量为0.016g,助剂质量为1.6 g时,较易生成自由基。反应时间为6 h较好。     

氯苄双羰基化反应动力学模型

氯苄双羰基化反应生成苯丙酮酸钙的过程是一个多相催化反应过程。通过对反应机理的研究,推导出实际操作的等温等压条件下反应动力学方程并用实验数据驾验证。     

Fabrication and Magnetic Properties of Composite Ni_(0.5)Zn_(0.5)Fe_2O_4/Pb(Zr_(0.52)Ti_(0.48))O_3 Nanofibers by Electrospinning

One-dimensional and quasi-one-dimensional nanostructure materials are promising building blocks for electromagnetic devices and nanosystems.In this work,the composite Ni0.5Zn0.5Fe2O4(NZFO)/ Pb(Zr0.52Ti0.48)O3(PZT) nanofibers with average diameters about 65 nm are prepared by electrospinning from poly(vinyl pyrrolidone) (PVP) and metal salts.The precursor composite NZFO/PZT/PVP nanofibers and the subsequent calcined NZFO/PZT nanofibers are investigated by Fourier transform infrared spectroscopy (FT- IR) ,X-ray diffraction (XRD),scanning electron microscopy (SEM).The magnetic properties for nanofibers are measured by vibrating sample magnetometer(VSM).The NZFO/PZT nanofibers obtained at calcination temperature of 900 °C for 2 h consist of the ferromagnetic spinel NZFO and ferroelectric perovskite PZT phases,which are constructed from about 37 nm NZFO and 17 nm PZT grains.The saturation magnetization of these NZFO/PZT nanofibers increases with increasing calcination temperature and contents of NZFO in the composite.     

多相态反应条件下十氢萘催化脱氢反应过程的研究

对以Raney-Ni为催化剂的十氢萘在多相态反应模式下的脱氢反应过程进行了研究.考察了反应温度(573～673 K)、催化剂用量(2～14 g)和反应液用量(0.5～2.0 mL)对十氢萘脱氢转化率的影响.实验发现催化剂表面形成的多相态条件与反应温度、反应液用量和催化剂用量紧密相连,通过对实验过程的分析,认为多相态反应模式的关键是对系统动态能量平衡的控制,当系统达到能量平衡时,十氢萘的脱氢转化率应该最高.实验结果表明,在653 K、12 g Raney-Ni和1.5 mL十氢萘条件下,十氢萘脱氢反应转化率最高,生成氢气的纯度达到99%,不含任何小分子杂质气体.     

用于模拟声发射信号的PZT柱状相位调制器设计

为了便于在实验室进行管道泄漏实验,通过PZT柱状相位调制器的逆压电效应模拟泄漏声发射信号,结合压电方程和机电等效原理推导了PZT柱状相位调制器的传递函数,并设计了PZT柱状相位调制器,同时进行了数值模拟．结果表明,设计的相位调制器可有效模拟低于25kHz的泄漏声发射信号．     

相变的序参量及对称性的研究

给出了一个三阶全对称的电学量作为　 相变的序参量,并且分别计算出了PZT、SrTiO3晶体 　 相 的各个分量．将计算出的这两种晶体 　 相的 矩阵与三阶全对称张量 的矩阵表相比较,得出PZT、SrTiO3晶体 　 相 所属对称群分别为D3、D2d．按照居里原理,这一序参量能很好的说明相变前后对称性的变化．     

表面效应对铁电纳米线性能的影响

在Jandau-Ginsburg-Devonshire(LGD)理论的基础上,建立了铁电纳米线的理论模型,并通过与第一原理计算结果的对比,建立了一种获取外延长度的新方法.对于Pb(Zr0 5 Ti0.5)0,(PZT)纳米线,其外延长度为20 nm.计算结果表明,在PZT纳米线中存在O.8 nm的临界直径,同时揭示了纳米线的表面效应对其铁电性能的抑制作用.     

STRUCTURE AND PROPERTY OF PIEZOELECTRIC CERAMICS OF QUATERNARY SYSTEM

Composite perovskite piezoelectric ceramicsof PMMN quaternary system were prepared by cold-pressingand solid-phase sintering.Piezoelectric modulus and densityof the samples were measured after polarization.X-raydiffraction analysis and SEM were used to prove the resultthat the major phase of the piezoelectric ceramic spectimenbased on PZT is PZT phase,which is tetragonal system andP_(4mm) space group.     

Characterization of PZT/PVC Composites Added with Carbon Black

1Introduction Piezoelectricceramicshavebeenusedastheconven tionalintelligentmaterialsforalongtime.Theirinterest ingpropertiesusedintransducersarehighpiezoelectric straincoefficient(d33),highelectromechanicalcoupling coefficient(Kp)[15].However,therelative…     

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.     

PZT压电陶瓷液相低温烧结技术的研究进展

阐述了PZF压电陶瓷烧结过程中的液相传质机理及实现液相烧结的主要途径.综述了PZY压电陶瓷材料的液相低温烧结研究方向与进展.     

Structure of Pb(Zr,Ti)O<Subscript>3</Subscript>(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.     

Preparation of Ni/PZT core-shell nanoparticles and their electromagnetic properties

The Ni nanoparticles coated with Pb(Zr,Ti)O_3(PZT) were synthesized by a sol-gel method and in situ reaction. And their structure, oxidation resistance, and electromagnetic properties were investigated. The X-ray diffraction patterns(XRD) exhibited that a small amount of impure phase characterized to Ni(OH)_2 was detected from the ammonia-treated Ni nanoparticles and the ammonia-treated Ni nanoparticles coated with PZT. After being pre-treated with aqueous ammonia, the PZT coating layer was more uniform and about 10 nm in thickness. The oxidation resistance of the ammonia-treated Ni nanoparticles coated with PZT, compared with that of the non-treated ones, was improved by about 66 ℃. The PZT shell layer prepared by in-situ reaction can greatly reduce the dielectric constant and improve the natural resonance loss at high frequency, so as to obtain the optimal impedance matching performance of the electromagnetic wave transmission.