退火对玻璃包覆Fe_(69)Co_(10)Si_8B_(13)非晶微丝磁性能及力学性能的影响

研究了退火对玻璃包覆Fe69Co10Si8B13非晶合金微丝磁性能和力学性能的影响。结果表明,退火温度为450℃时,矫顽力和剩磁比最小,轴向和径向矫顽力分别为1.8Oe和8.5Oe,比退火前降低了31%和36%,轴向和径向剩磁比分别为0.031和0.012,比退火前降低了74%和63%。当退火温度低于450℃时,芯丝抗拉强度基本保持不变,平均抗拉强度约2500MPa;当退火温度高于450℃时,芯丝抗拉强度迅速降低。未退火及退火温度低于450℃退火时,合金芯丝断口存在少量的脉状花样,且脉状花样及花样交叉的数量越多,所对应的芯丝抗拉强度越高;经500℃以上退火后,放射状撕裂区占芯丝断口大部分面积,芯丝表现出更大的脆性。在450℃20min条件下退火,微丝具有较低的矫顽力和较高的强度,综合性能优良。     

Sb_2O_3掺杂对(Na_(1-x)K_x)_(0.5)Bi_(0.5)TiO_3无铅压电陶瓷性能的影响

采用传统工艺制备了(Na0.84K0.16)0.5Bi0.5TiO3压电陶瓷,研究掺杂离子Sb3+对(Na0.84K0.16)0.5Bi0.5TiO3微观结构和电性能的影响。结果表明烧结温度在1160℃时,样品密度达到最大值5.85g/cm3;X射线衍射(XRD)分析所有陶瓷样品均为钙钛矿相,Sb2O3的掺杂只改变晶胞体积或产生铋离子空位或钠离子空位,不形成异相;掺杂量在0.4%~0.6%时介电常数先增加后减小,介电损耗呈现增大趋势;掺杂0.5%的Sb2O3时,d33最大为142pC/N。     

Synthesis,characterization and dielectric behavior of (ES)-form polyaniline/cerium(III)-nitrate-hexahydrate composites

In this study, morphological, thermal and dielectric properties of chemically synthesized polyaniline (PANI) and its cerium(III)-nitrate-hexahydrate (Ce(NO₃)₃·6H₂O) doped composites with various doping levels were investigated. Characteristic bands of emeraldine salt (ES)-form of PANI was clearly observed in UV–visible (UV–vis) and Fourier transform infrared (FTIR) spectroscopies. Thermal analyses carried out by Differential scanning calorimetry (DSC) indicated that there was a glass transition at about 70 °C and the doping process increased thermal stability of the polymer. In the surface morphologies examined by scanning electron microscopy (SEM), various microstructures depending on the doping level were observed. Real dielectric constant exhibited a significant decrease due to the increase in the doping level especially at higher frequencies. Conductivity mechanisms of PANI and its composites were investigated by universal power law as conventional models could not provide a complete picture for all the samples. Dramatic increases up to 45, 35 and 30 times in the conductivity of 10% doped PANI were observed for 300, 350 and 400 K, respectively.     

新型超微晶Fe_（81）P_（12）C_3Si_（2．5）Cu_1Mo_（0．5

在室温下，借助Ｍｏｓｓｂａｕｅｒ谱技术，研究非晶合金Ｆｅ_（８１）Ｐ_（１２）Ｃ_３Ｓｉ_（２．５）Ｃｕ_１Ｍｏ_（０．５）晶化过程中局域结构的变化。发现整个晶化由两个阶段组成：第一个阶段（３００－３６０℃之间退火）为α－Ｆｅ相的形核与长大阶段；第二个阶段主要为Ｆｅ_３Ｐ相的形核与长大阶段。同时该合金在３６０℃退火获得最佳软磁性能。还讨论了软磁性能与结构变化之间的关系。     

Facile preparation of poly(vinyl alcohol) nanocomposites with pristine layered double hydroxides

In this paper, nano-sized Mg–Al layered double hydroxide (LDH) was synthesized by a fast nucleation and slow aging method. The structures of LDH were characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM) and photon correlation spectroscopy (PCS). Poly(vinyl alcohol) (PVA) nanocomposites with different LDH loadings were prepared by water solution casting method. TEM observations show that the LDH nanoplatelets are uniformly dispersed in the PVA matrix. Tensile tests indicate that the elastic modulus and the tensile strength of PVA are improved by about 15% and 54%, respectively, when incorporating with 2 wt% LDH. The improvement of mechanical properties of PVA can be attributed to fine dispersion of LDH, good compatibility and strong interaction between PVA and LDH. In addition, the presence of LDH decreases the decomposition rates at the second stage and improves the amount of residues of PVA. Meanwhile, the transparency of the nanocomposite films is maintained compared with neat PVA.     

缺铁配方W型BaZn_xCo_(2-x)Fe_(15.5)O_(27)铁氧体复合物微波性能调控研究

本文采用缺铁配方BaZnxCo2-xFe15.5O27制备W型六角铁氧体,并深入研究了不同Zn离子和Co离子含量对铁氧体复合物微波性能的影响。结果表明,缺铁配方六角铁氧体复合物拥有较低的介电常数,控制Zn离子Co离子可以有效调控铁氧体复合物介电常数以及共振频率。同时通过在铁氧体复合物中添加纳米碳管调控复合物介电常数,证明纳米碳管添加量在一定范围内,铁氧体复合物可以获得优秀的微波吸收性能。     

Poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (3,4-ethylenedioxythiophene)-few walled carbon nanotube (PEDOT-FWCNT) nanocomposite based thin films for Schottky diode application

Transparent, conductive films of poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (3,4-ethylenedioxythiophene)-few walled carbon nanotube (PEDOT-FWCNT) nanocomposite were synthesized by in-situ oxidative polymerization and investigated for their Schottky diode property. The prepared films were characterized by UV–Vis spectroscopy, thermal gravimetric analysis (TGA), surface resistivity, cyclic voltametery, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). SEM reveals the formation of homogeneous and adhesive polymer films while HRTEM confirms the uniform wrapping of polymer chains around the nanotube walls for PEDOT-FWCNT film. Improved thermal stability, conductivity and charge storage property of PEDOT in the presence of FWCNT is observed. Among different compositions, 5 wt. % of FWCNT is found to be optimum with sheet resistance and transmittance of 500 Ω sq⁻¹ and 77%, respectively. Moreover, the electronic and junction properties of polymer films were studied and compared by fabricating sandwich type devices with a configuration of Al/PEDOT or PEDOT-FWCNT nanocomposite/indium tin oxide (ITO) coated glass. The measured current density-voltage characteristics show typical rectifying behavior for both configurations. However, enhanced rectification ratio and higher forward current density is observed in case of PEDOT-FWCNT based Schottky diode. Furthermore, reliability test depicts smaller hysteresis effect and better performance of PEDOT-FWCNT based diodes.     

Effects of poly(oxyethylene)-block structure in polyetheramines on the modified carbon nanotube/poly(lactic acid) composites

The hybrids of multi-walled carbon nanotube and poly(lactic acid) (MWCNT/PLA) were prepared by a melt-blending method. In order to enhance the compatibility between the PLA and MWCNTs, the surface of the MWCNTs was covalently modified by Jeffamine® polyetheramines by functionalizing MWCNTs with carboxylic groups. Different molecular weights and hydrophilicity of the polyethermaines were grafted onto MWCNTs with the assistance of a dehydrating agent. The results showed that low-molecular-weight Jeffamine® polyetheramine modified MWCNTs can effectively improve the thermal properties of PLA composites. On the other hand, high-molecular-weight and poly(oxyethylene)-segmented polyetheramine could render the modified MWCNTs of well dispersion in PLA, and consequently affecting the improvements of mechanical properties and conductivity of composite materials. With the addition of 3.0 wt% MWCNTs, the increment of E′ of the composite at 40 °C was 79%. For conductivity, the surface resistivity decreased from 1.27 × 10¹² Ω/sq for neat PLA to 8.30 × 10⁻³ Ω/sq for the composites.     

聚噻吩衍生物的性质及其应用

聚３－烷基噻吩是可溶可溶的共轭聚合物，又具有特殊的电学和光学特性，如热色现象，凝胶色变现象，溶剂色变，光催化性质等可在多方面得到应用，如电发光二极管等引起人们的极大兴趣。本文对其性质应用进行评述和介绍。     

Structural and dielectric properties of (001) and (111)-oriented BaZr0.2Ti0.8O3 epitaxial thin films

We have grown and characterized BaZr_0.2Ti_0.8O₃ (BZT) epitaxial thin films deposited on (001) and (111)-oriented SrRuO₃-buffered SrTiO₃ substrates by pulsed laser deposition. Structural and morphological characterizations were performed using X-ray diffractometry and atomic force microscopy, respectively. A cube-on-cube epitaxial relationship was ascertained from the θ-2θ and φ diffractograms in both (001) and (111)-oriented films. The (001)-oriented films showed a smooth granular morphology, whereas the faceted pyramid-like crystallites of the (111)-oriented films led to a rough surface. The dielectric response of BZT at room temperature was measured along the growth direction. The films were found to be ferroelectric, although a well-saturated hysteresis loop was obtained only for the (001)-oriented films. High leakage currents were observed for the (111) orientation, likely associated to charge transport along the boundaries of its crystallites. The remanent polarization, coercive field, dielectric constant, and relative change of dielectric permittivity (tunability) of (111)-oriented BZT were higher than those of (001)-oriented BZT.     

Synthesis and Characterization of Fe_(50)Cr_(14)Mo_(14)C_(14)B_6Gd_2 Bulk Amorphous Steel

Bulk amorphous steel having 7 mm thickness was synthesized to evaluate its thermal stability and mechanical properties.The steel was synthesized by Cu mold casting technique using 1-2N pure metals.Characterization of the material was done by X-ray diffraction,differential scanning calorimetry and scanning electron microscopy.The activation energies were calculated by Kissinger equation and it was found that the steel had better stability against crystallization.Mechanical properties like Vicker s hardness,n...     

Mn替代Ni对(La0.8Nd0.2)2Mg(Ni0.9-xCo0.1Mnx)9合金储氢及电化学性能的影响

在Ar保护下采用磁悬浮感应熔炼制备(La0.8Nd0.22)Mg(Ni0.9-xCo0.1Mnx)9(x=0,0.05,0.1,0.15)合金,系统研究了元素替代及退火处理对合金相结构、吸放氢性能及电化学性能的影响。结果表明,合金相主要由(La,Nd)Ni5相、LaMg2Ni9相和(La,Nd2)Ni7相组成,当x=0.15时,(La,Nd)2Ni7相消失。随着Mn取代量的增加,合金的储氢量、放电容量先增加后减小,Mn的添加提高了合金的充放电循环稳定性。经1073K退火处理后合金的放电容量得到提高,循环稳定性能得到明显改善。     

等温退火Fe_（73．5）Cu_（1．0）Mo_（3．0）Si_（13．5）B_（9．0）纳米软磁合金的磁性及其影响因素

研究了５２０℃下等温退火Ｆｅ_（７３．５）Ｃｕ_（１．０）Ｍｏ_（３．０）Ｓｉ_（１３．５）Ｂ_（９．０）纳米软磁合金的磁性，发现当退火时间ｔａ为４０ｍｉｎ时，合金的起始磁导率μｉ最高，约为５×１０~４，探讨了磁性的影响因素。     

Characterization of nanostructured photosensitive (NiS)x(CdS)(1−x) composite thin films grown by successive ionic layer adsorption and reaction (SILAR) route

Recently ternary semiconductor nanostructured composite materials have attracted the interest of researchers because of their photovoltaic applications. Thin films of (NiS)_x(CdS)_(1−x) with variable composition (x = 1-0) had been deposited onto glass substrates by the successive ionic layer adsorption and reaction (SILAR) method. As grown and annealed films were characterised by X-ray diffraction, scanning electron microscopy and EDAX to investigate structural and morphological properties. The (NiS)_x(CdS)_(1−x) films were polycrystalline in nature having mixed phase of rhombohedral and hexagonal crystal structure due to NiS and CdS respectively. The optical and electrical properties of (NiS)_x(CdS)_(1−x) thin films were studied to determine compsition dependent bandgap, activation energy and photconductivity. The bandgap and activation energy of annealed (NiS)_x(CdS)_(1−x) film decrease with improvement in photosensitive nature.     

丙烯腈-丙烯酰胺溶液共聚合及其产物热性能研究

通过改变原料中丙烯腈(AN)与丙烯酰胺(AM)的配比,获得不同共聚组成的聚丙烯腈。结合凝胶渗透色谱(GPC),X射线衍射(XRD),核磁共振(NMR),失重差热联用(DSC TG)等考察了AM对聚合反应的影响,剖析了聚合物的结构特征,评价了共聚产物在50℃～500℃氮气中的热性能。研究结果表明:反应物料中AN与AM的配比对产物分子量、转化率、共聚组成、共聚物的晶态结构和立体结构以及放热行为有着极大的影响。AM的加入对共聚产物分子量和聚合转化率的影响趋势相反。当AN与摩尔分数为0.75%的AM反应时,转化率最高,分子量最低。在AM的摩尔分数为0%～3.78%的条件下,随着AM加入量的增多,共聚组成中AM量也增多,聚合物的规整度增高,结晶度变大,晶粒尺寸增加。AM的引入能够使PAN/AM环化提前,降低放热速率。并且,环化机理受共聚组成影响。AM的引入使得共聚物存在两种环化增长方式(离子增长和自由基增长)。随着AM引入量的增多,氰基的自由基环化增长越来越少,离子环化增长越来越多,存在自由基机理向离子机理过渡的趋势。     

Different thallium(III) oxide nano-structures from direct thermal decomposition of two thallium(I) coordination polymers

Two thallium(I) coordination polymers, [Tl(3-np)] and [Tl(2,4-dnp)], 3-np⁻ = 3-nitrophenoxide and 2,4-dnp⁻ = 2,4-dinitrophenoxide, have been synthesized and characterized by elemental analyses and IR spectroscopy. Flower-like nano-structure and nano-powders thallium(III) oxide, Tl₂O₃, have been prepared by direct thermal decomposition of two different Tl(I) coordination polymers, [Tl(3-np)] and [Tl(2,4-dnp)]. The nano-materials were characterized by scanning electron microscopy, X-ray powder diffraction (XRD) and IR spectroscopy. The thermal stability of nano-structure Tl₂O₃ was studied by thermal gravimetric and differential thermal analyses and showed that there is no reportable loss of weight in the TGA curves that proves the existence of thallium(III) oxide. This study demonstrates that coordination polymers may be suitable precursors for the preparation of nanoscale materials with different and interesting morphologies.     

聚乳酸-聚丁二酸丁二醇酯嵌段共聚体系对聚乳酸熔体流变性能的影响

采用未封端的聚乳酸(PLA1)和聚丁二酸丁二醇酯(PBS)通过大分子链末端直接脱水酯化反应制备聚乳酸-聚丁二酸丁二醇酯嵌段共聚体系(LB),并对比研究LB体系及纯PBS两种改性剂对封端聚乳酸(PLA)熔体流变性能的影响。流变测试结果证明,LB或PBS的添加均使PLA的储能模量有较明显的提高。但当改性剂的含量相同时,LB对PLA熔体流变性能的提高幅度明显高于PBS,这可能是因为在LB共聚体系中除传统的"海岛"结构外还形成了新的PLA1-PBS"核壳"结构。     

热处理对Ba2Co0.6Zn1.0Cu0.4Fe12O22（Co2Y）铁氧体磁性能的影响

用化学共沉淀法制备均匀、细小、高活性的Y型平面六角铁氧体前躯体粉体,将前躯体在600-1050℃煅烧后在1000℃烧结,并对烧结样品进行表征,研究了热处理对Ba₂Co_0.6Zn_1.0Cu_0.4Fe₁₂O₂₂（Co₂Y）铁氧体性能的影响。结果表明,前躯体的颗粒粒度分布集中,粒径大小约为3μm。在较低温度（900℃）煅烧的样品能形成纯相Y型平面六角铁氧体;其比饱和磁化强度随着煅烧温度的升高而增大,对应磁环的起始磁导率先降低后增大;在900℃煅烧的样品σ_s≈17.262 A·m²·kg^-1、H_c≈5.146 kA·m^-1,频率为100 MHz,其μ_i≈3.7、Q≈13.4。     

Low-field magnetoresistance effect in core-shell structured La(0.7) Sr(0.3) CoO(3) nanoparticles

Core-shell structured La(0.7) Sr(0.3) CoO(3) nanoparticles are synthesized and their magnetic and magneto-transport properties are investigated. In these core-shell La(0.7) Sr(0.3) CoO(3) nanoparticles, the cores are single-crystalline and ferromagnetic, whereas the shells are noncrystalline and predominantly paramagnetic. Moreover, the insulating-like shells can serve as a good spin tunneling barrier. Therefore, in such a special core-shell structure, the spin-polarized interparticle tunneling is improved due to the existence of shells, which thus induces an enhanced low-field magnetoresistance effect.     

Dielectric anisotropy and electrical properties of the copper phthalocyanine (CuPc): 4–4′-n-Heptylcyanobiphenyl (7CB) composite liquid crystals

Dielectric anisotropy and electrical properties of the copper phthalocyanine (CuPc): 4–4′-n-heptylcyanobiphenyl (7CB) composite liquid crystals have been investigated. Liquid crystals exhibit dielectrically-controlled positive dielectric anisotropy (p-type Δɛ) and the dielectric anisotropy changes from positive to negative dielectric anisotropy (n-type Δɛ) behavior with frequency of applied electrical field. The critical frequency f_c values for the 7CB and CuPc doped 7CB liquid crystals were found to be 602 kHz and 518 kHz, respectively. This indicates that CuPc doping causes a decrease in the critical frequency. The splay elastic coefficients of the 7CB and CuPc doped 7CB liquid crystals were determined and CuPc doping increases the splay elastic coefficient of 7CB liquid crystal. The 7CB liquid crystal exhibits a voltage-controlled differential negative resistance (VCNR) behavior and CuPc doping affects significantly VCNR behavior of 7CB.