Enhanced photoluminescence and electrical properties of 0-3 type ZnO/Bi3.6Eu0.4Ti3O12 nanocomposite thin films

0-3 type ZnO/Bi_3.6Eu_0.4Ti₃O₁₂ (BEuT) nanocomposite films with ZnO nanopowders in BEuT host were prepared by chemical solution deposition. The effects of ZnO content on the structure, photoluminescence, and electrical properties of the films were investigated. The ZnO/BEuT molar ratio strongly affected the grain size and growth orientation of BEuT, dielectric and ferroelectric properties, as well as emission intensity. The nanocomposite films showed strong red emission peaks due to ⁵D₀ → ⁷F₁ and ⁵D₀ → ⁷F₂ transitions of Eu³⁺ ions. Good electrical properties with high dielectric constant of 480 (at 1 kHz) and large remanent polarization (2P_r) of 32 μC/cm² were obtained for the nanocomposite films having a ZnO/BEuT molar ratio of 1:2. The mechanisms for enhanced photoluminescence and electric properties were discussed. The results suggest that the nanocomposite thin films are promising candidate materials for multifunctional optoelectronic devices.     

加压过滤机在铜钼分离工艺中的应用

通过利用加压过滤机新设备,运用新的过滤技术,使铜钼分离工艺流程畅通,有效解决了分离工艺中高碱度、微细粒级物料脱水及确保产品水分双重问题。实现铜钼混合精矿中铜与钼资源的综合回收,提高企业核心技术竞争力,促进企业科学发展,经济效益和社会效益明显。     

High Temperature Rapid Tempering Process of SS400 Steel With Thermomechanical Simulation Tester

 The effect of refined precipitations and dispersed phases on the toughness of SS400 steel was investigated by rapid tempering with thermomechanical simulation tester, and the electromagnetic induction rapid tempering process was simulated. The conventional tempering and rapid tempering process were proceeded respectively, and both samples were quenched in 10% of agitated iced brine. The tempering temperatures were designed as 560, 620 and 680 ℃, respectively. Rapid tempering specimens were heated at a heating rate of 20 ℃/s, and all samples of these three tempering temperatures were maintained 30, 40 and 50 s with the Gleeble1500-D tester, respectively. The impact test at -40 ℃ were carried out on a Charpy impact machine (CBD-300) with a maximum measurement range of 300 J and the microstructures were analyzed in detail using optical microscope (OM) and scanning electron microscope (SEM). The experiment results show that the upper bainite, martensite and small amount of austenite were obtained in the rapidly quenched samples. In comparison to the conventional process, the matrix microstructure was changed from the larger size and bulk ferrite to the refined banding structure, and the cementites were obviously refined and precipitated inside the grains and along the grain boundaries. The cryogenic impact test implies that the maximum values of impact toughness with holding time of 30 or 50 s are achieved at tempering temperature of 620 ℃. Furthermore, a favorite value of impact toughness with holding time of 40 s is available.     

Investigations on Al/BaTiO3/GaN MFS structures

A metal–insulator–semiconductor (MIS) device structure has been established on GaN by using BaTiO₃, a ferroelectric material, as an insulating layer. The composition of the deposited ferroelectric layers was studied using X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray (EDX) analysis. Fabricated Al/BaTiO₃/GaN metal–ferroelectric–semiconductor (MFS) structures have been characterised through capacitance–voltage (C–V) measurements. Improved C–V characteristics have been observed in comparison to other traditional oxide insulators. An inversion of GaN MFS structures has been attained just for the applied voltage of 5 V due to the high dielectric constant and large polarisation field of the gate ferroelectric layer. The bias stress measurements indicate a high stability of the ferroelectric material over a period of 10⁴ s.     

退火处理对B4C-CeB6/Al复合材料相组成及其力学性能的影响

首次向B4C中添加CeO2,原位合成制备了B4C-CeB6多孔增强体。然后采用无压浸渗法,将金属铝渗入B4C-CeB6增强体中,制备出B4C-CeB6/Al复合材料,对其进行了相组成的分析和力学性能的测试。对无压浸渗法制备的B4C-CeB6/Al复合材料进行不同温度下的退火处理后,对其也进行了相组成的分析和力学性能的测试。结果表明,在本试验的退火温度下,退火后的B4C-CeB6/Al复合材料的抗弯强度相比未退火的有显著提高;而退火后的B4C-CeB6/Al复合材料的断裂韧性略有提高;退火处理对复合材料硬度几乎没有影响。将未退火的B4C-CeB6/Al复合材料和退火处理后的B4C-CeB6/Al复合材料都用XRD检测其中的相组成,发现其中相组成无变化,但是复合材料中各相的含量变化却各不相同。     

Microwave heating synthesis of spindle-like LiMnPO4/C in a deep eutectic solvent

Orthorhombic structure LiMnPO₄/C with space group Pnmb was synthesized using a microwave heating process in a chloride/ethylene glycol-based deep eutectic solvent (DES) at 130 °C for 30 min under atmospheric pressure. The prepared sample was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and electrochemical tests. LiMnPO₄/C prepared in a DES has a nano-spindle form coated with a carbon layer (approximately 3 nm thick). This spindle-like LiMnPO₄/C material delivers a discharge capacity of 129 mA h g^–1 with a capacity retention ratio of approximately 96.1% after 100 cycles at 1 C. Even at 5 C, it still gives a discharge capacity of 106 mA h g^–1, exhibiting good rate performance and cycle stability. The results of this work show that the chloride/ethylene glycol-based DES can act as a crystal-face inhibitor to adjust the oriented growth and morphology of LiMnPO₄. Furthermore, deep eutectic solvents could find a wide application in the synthesis of electrode materials with special morphologies for lithium ion batteries.     

Tribological properties of NiCr–ZrO2(Y2O3)–SrSO4 composites at elevated temperatures

The effect of SrSO₄ content on the tribological properties of NiCr–30wt%ZrO₂(Y₂O₃) (NC30Z) cermet was evaluated over a wide temperature range from room temperature to 1000 °C. The results indicated that the inclusion of SrSO₄ effectively improved the friction coefficients and wear rates of NC30Z cermet above 400 °C. NC30Z–5SrSO₄ composite against alumina ball exhibited satisfactory tribological performance, which was attributed to synergistic lubrication of pseudocubic-SrZrO₃ and NiCr₂O₄ between 400 °C and 800 °C and cubic-SrZrO₃, NiCr₂O₄, NiO and Cr₂O₃ at 1000 °C.     

新型复合电解质PEO-LiClO4-Cex Ti（1-x）O2的制备与性能研究

以PEO-LiC lO4为基质材料,以CeO2和TiO2作为无机填料,采用原位复合法与溶液浇铸法相结合的方法制备了PEO-LiC lO4-CexTi1-xO2全固态复合聚合物电解质薄膜（CPE）.利用交流阻抗方法和差示扫描量热法对CPE的电导率、玻璃化转变温度和结晶度进行了研究.结果表明,添加不同粒径的纳米氧化物可在不同尺度上更加有效地破坏聚合物基体的结晶行为,增大离子传输所需的无定形区域,同时,降低了聚合物PEO的玻璃化转变温度和结晶度,并使其结晶度在较长时间内维持在较低水平,最终使离子电导率得到了明显提升.     

导电塑料表面电化学镀镍和镀层表征

为了提高导电塑料的表面硬度、强化表面导电行为,采用电沉积的方法在导电塑料上镀镍,研究了镀液温度、电镀时间和阴极电流密度对镀层厚度增长速度的影响,利用扫描电镜和金相显微镜对镀层进行了表征,采用粘结拉脱法测量了镀层与基体之间的结合力,采用电化学方法研究了镍镀层在NaCl水溶液中的腐蚀行为.结果表明:阴极电流密度为2.0A/dm2、镀液温度为60℃时,可以得到0.68μm/min的平均镀层增长速率;镍镀层可以保留导电塑料基体的表面特征,镍镀层与基体之间结合力可以达到2.3MPa以上;光亮镍镀层在NaCl水溶液中的腐蚀电位高于哑镍镀层的腐蚀电位,且在相同的极化电位下,光亮镍镀层阳极溶解速率也较低.