Ultrafast sintering of La–Ca–Mn–O bulk ceramics by thermal plasma assisted heating

This paper reports a novel and low-cost thermal plasma assisted heating method for ultrafast sintering of rare-earth-based perovskite manganites. An indigenously designed DC thermal plasma reactor has been used to sinter La_0.67Ca_0.33MnO₃ (LCMO) colossal magnetoresistance (CMR) material. Highly dense (96% of theoretical density) crystalline bulk LCMO ceramics were prepared within 2.5 min of sintering time. Plasma-sintered LCMO bulk ceramics showed enhanced T_C (272 K), which is close to T_IM (275 K) as compared to the conventional sintered LCMO [J.M. De Teresa, M.R. Ibarra, J. Blasco, J. Garcia, C. Marquina, P.A. Algarabel, Z. Arnold, K. Kamenev, C. Ritter, R. von Helmolt, Phys. Rev. B 54 (1996) 1187] sample. We observe that the thermal plasma heating process offers a unique advantage for quick physical densification and hence sintering within a few minutes.     

太空育种射干的X射线荧光及X射线衍射分析和表征

联用X射线荧光光谱(XRF)和粉末X射线衍射(PXRD)方法,对我国独创的第4代太空诱变育种射干中多种元素种类和含量及晶态物质进行了研究。结果表明:太空组射干K元素含量比地面组、对照品分别提高了1.03和0.31倍,Mg元素分别提高了1.44和0.06倍,Ca,Mn和Fe元素含量比地面组分别提高了0.95,0.30和0.29倍,Al元素比地面组、对照组分别降低了38.5%和85.5%,并在射干中鉴别出一水草酸钙(CaC2O4.H2O)晶体,晶体含量是地面组<太空组<对照品。从而可得出结论:太空射干中人体必需的矿质元素比地面组都更接近或优于对照品。文章研究结果和方法对筛选品质优良的太空药材籽种和推广种植太空药材以及建立中药材质量评价标准,有积极的作用和重要意义。     

柔性有机电致发光器件导电基板的工艺性能

在聚对苯二甲酸乙二醇酯(PET)柔性衬底上采用直流磁控溅射技术制备了氧化铟锡(ITO)透明导电薄膜,研究了衬底温度、溅射功率和溅射压强等工艺条件对薄膜光电性能的影响,并利用原子力显微镜(AFM)表征了衬底及ITO薄膜的表面形貌。结果表明,在PET衬底温度50℃、溅射功率100W和溅射压强2.66×10-1Pa的条件下,可以得到低方阻(50Ω/□)和高透过率(>90%)的透明导电薄膜。以此柔性ITO衬底为阳极,制备了结构为PET/ITO/NPB/Alq3/Mg∶Ag的柔性有机电致发光器件,在驱动电压为13V时,器件的发光亮度达到了2834cd/m2。     

100kV直流高温超导电缆终端应力锥设计

本文提出了一种新的单直线应力锥设计方法,根据PPLP材料的绝缘特性,结合超导电缆的本体尺寸和设计电压,给出了增饶绝缘厚度和应力锥轴向长度的设计数据,其中增饶绝缘厚度为3.5 mm,应力锥轴向长度为38.5 mm,并对单直线应力锥进行电场数值分析,结果表明,所设计的单直线应力锥满足100 kV直流高温超导电缆运行要求。     

单斜ZnP2负极材料的锂化机理及性能

过渡金属磷化物电位低且比容量高, 是有发展前景的锂离子电池(LIBs)负极材料. 其中, ZnP₂属于双活性负极材料, Zn与P都能与Li⁺发生反应, 储Li⁺性能更具有竞争力. 但是, 对于ZnP₂的锂化机理及产物尚不明确. 采用第一性原理计算和电化学测试方法研究了ZnP₂的电子性质和电化学性能, 通过理论计算和实验测试相结合阐述了ZnP₂的锂化机制. 首先, 以密度泛函理论(DFT)计算揭示了ZnP₂的锂化机理、Li⁺扩散路径、势垒和理论比容量(1477 mAh/g). 其次, 通过直流电弧等离子体法及固相烧结法合成ZnP₂, 并测试其首圈放电曲线, 显示放电容量为1439 mAh/g, 与理论计算结果相近. 此外, 薄膜X射线衍射(XRD)检测最终产物成分为LiZn和Li₃P, 与DFT计算结果一致.     

Liquid crystal aligning capabilities on surface-reformed indium-doped zinc oxide films via ion-beam exposure

We investigated the characteristics of a solution-processed indium-doped zinc oxide (In:ZnO) film formed via ion-beam (IB) irradiation as a liquid crystal (LC) alignment layer. The In:ZnO film was deposited using solution processing and cured at various temperatures. Uniform LC alignment was observed at all curing temperatures in cross-polarised optical microscopy images. A regular pre-tilt angle supported these results and showed homogeneous LC alignment. Several surface analyses were conducted to evaluate the effect of IB irradiation on the In:ZnO film surface. X-ray diffraction analysis showed an amorphous structure both before and after IB irradiation, and physical surface reformation was observed using atomic force microscopy. Root mean square surface roughness was reduced and a smooth surface was achieved after IB irradiation. X-ray photoelectron spectroscopy was used to detect chemical surface reformation. It was found that the IB irradiation broke the metal-oxide bonds and increased the occurrence of oxygen vacancies, which affected the van der Waals forces between the LC molecules and the In:ZnO film surface. Electrical performance was observed to identify the possibility of using the In:ZnO film in LC applications. Enhanced electro-optical performance was measured and zero residual DC voltage which was verified using a capacitance-voltage curve was achieved.     

Jasmonic acid changes the composition of essential oil isolated from narrow-leaved lavender propagated in in vitro cultures

The aim of the present study was to determine the effect of jasmonic acid added to the culture medium on composition of Lavandula angustifolia essential oils. The chemical composition was determined by gas chromatography coupled to mass detector (GC/MS). The experiment was conducted with the use of MS medium supplemented with increasing concentration of JA (0.2, 0.5, 1, 1.5 mg?dm^?3). It was found that the analysed essential oils varied in terms of chemical composition depending on the content of JA in the medium. All obtained essential oils were characterised by a high content of σ-cadinene (17.06–29.64%), borneol (6.66–17.47%), caryophyllene oxide (8.30–14.01%), τ-cadinol (4.87–9.16%), beta-caryophyllene (3.54–6.57%), 1.8-cineole (1.94–5.87%), β-pinene (1.48–3.05%), geranyl acetate (0.56–2.14%) and myrtenal (0.65–2.14%).     

Magnetization and structural studies of Mn doped ZnO nanoparticles: Prepared by reverse micelle method

Single phase Mn (2.5 at%) doped ZnO nanocrystalline samples were synthesized by reverse micelle method as characterized by Rietveld refinement analysis of X-ray diffraction data, high resolution transmission electron microscopy and selected area electron diffraction analyses. The X-ray photoelectron spectroscopy and electron paramagnetic resonance (EPR) studies indicated that manganese exist as Mn²⁺ in ZnO lattice. DC magnetization measurements as a function of field and temperature, of 2.5 at% Mn doped ZnO nanoparticles annealed at 675 K, showed room temperature ferromagnetism (RTF). This observation is further confirmed by the EPR spectrum of the sample, which shows a distinct ferromagnetic resonance signal at room temperature. These results indicate that the observed RTF in Mn-doped ZnO may be attributed to the substitutional incorporation of Mn at Zn sites.     

绒面ZnO透明导电薄膜

采用孪生ZnO (Al2 O3 ∶2 % )对靶直流磁控溅射制备高透过率、高电导率的平面ZnO薄膜 (迁移率为 5 .5 6cm2 /V·s,载流子浓度为 4 .5 7× 10 2 0 cm-3 ,电阻率为 2 .4 6× 10 -3 Ω·cm ,可见光范围 (380～ 80 0nm)平均透过率大于 85 % )。用酸腐蚀的方法 ,可以获得绒面效果 ,而反应气压对绒面效果没有影响 ,薄膜的电学特性没有变化 ,绒面对光散射作用增强 ,导致相对于平面ZnO薄膜的透过率要低一些 (可见光范围平均透过率大于 80 % )。