Co-doping effects of (Al,Ti, Mg) on the microstructure and electrical behavior of ZnO-based ceramics

Co-doped ZnO-based ceramics using Al, Ti, and Mg ions in different ratios were synthesized with the objective to investigate the doping effects on the crystalline features, microstructure and the electrical behavior. For Al and Ti doping, a coexistence of crystalline phases was shown with a major wurtzite ZnO structure and secondary spinel phases (ZnAl₂O₄, Zn₂TiO₄, or Zn_aTi_bAl_cO_d), while Mg doping did not alter significantly the structural features of the wurtzite ZnO phase. The electrical behavior induced by Al, Ti, and Mg co-doping in different ratios was investigated using Raman, electron paramagnetic resonance (EPR) and ²⁷Al and ⁶⁷Zn solid-state nuclear magnetic resonance (NMR). Al doping induces a high electrical conductivity compared to other doping elements. In particular, shallow donors from Zn_i-Al_Zn defect structures are inferred from the characteristic NMR signal at about 185 ppm; that is, quite far from the usual oxygen coordinated Al. The Knight shift effect emanating from a highly conducting Al-doped ZnO ceramics was considered as the origin of this observation. Oppositely, as Ti doping leads to the formation of secondary spinel phases, EPR analysis shows a high concentration of Ti³⁺ ions which limit the electrical conductivity. The correlation between the structural features at the local order, the involved defects and the electrical behavior as function of the doping process are discussed.     

Combustion synthesis of InSe,In2Se3, and GaSe

InSe, In₂Se₃, and GaSe are important III‐VI semiconductors and are attractive for electronic, optical, and optoelectronic applications. This paper reports a fast and cheap way called combustion synthesis to prepare InSe, In₂Se₃, and GaSe. Bulk samples with relative densities up to 98% are directly produced in a few seconds. The samples show a high phase purity, correct stoichiometry, and lamellar crystals larger than 100 μm. By optical absorption, the bandgaps of InSe, In₂Se₃, and GaSe are determined to be 1.08, 1.24 and 1.75 eV, respectively.     

火力发电厂循环排污水处理回用技术的比较分析

根据实际工程案例对目前国内火力发电厂循环水排污水处理回用的3种技术方案进行了分析比较,包括处理工艺、效果及技术特点等,并对循环排污水技术的发展提出了建议。     

Fast preparation of Cu(In,Ga)Se2 and CuIn(S,Se)2 bulk materials by combustion synthesis

CuIn_1‐xGa_xSe₂ and CuIn(S_ySe_1‐y)₂ bulk materials with relative densities of 93.4%‐96.2% have been prepared by combustion synthesis, from elementary reactants and in a reaction time of a few seconds. The samples have a chalcopyrite lattice structure, and the lattice parameters decrease with increasing x and y. The substitution of In with Ga and Se with S in CuInSe₂ causes an increase in the bandgap. In combustion synthesis, the high temperature accelerates the reaction and results in fast densification, the high heating rate simplifies the reaction path and avoids the formation of intermediate compounds, and the gas pressure depresses the evaporation of reactants. As a fast, furnace‐free, and scalable technique, combustion synthesis may offer a low‐cost way to produce CuInSe₂‐based materials and bring new possibilities to their commercial applications.     

聚苯胺/活性炭复合材料的共价键构筑及电容性能

导电聚苯胺(PANI)与活性炭(AC)构筑复合电极材料是当前制备高性能超级电容器电极材料的热点研究方向。其关键点之一是制备出炭与PANI两种材料均匀分散、且具有相当牢固强度连接界面的复合材料。为此,以AC为基材,对其进行功能化处理后,将苯胺在其表面原位聚合,获得具有界面共价键连接的PANI/AC复合材料(PANI–c–AC)复合材料。通过扫描电子显微镜、元素分析、傅里叶变换红外光谱、X射线衍射仪及电化学工作站等测试并研究其结构与电容性能。结果表明,具有界面共价键连接的PANI–c–AC复合材料比电容值(393.3 F/g)最高,既优于单一AC(111.8 F/g)与PANI(296.2 F/g),也优于无共价键连接的PANI–AC复合材料(360.5 F/g)。     

水性触感油在烟用接装纸上的应用研究

以水性聚氨酯乳液为主树脂,水性苯丙乳液为辅助树脂,搭配滑爽助剂、消泡剂、 pH调节剂和溶剂,制备出具有特殊功能的水性触感油,并将其应用于烟用接装纸。通过考察不同组分及含量对触感层的外观效果、附着力、耐磨性、手感舒适度、抗返黏性、动/静摩擦系数、接触角等参数的影响,结合实际上机打样验证,筛选出具有良好印刷适应性的水性触感油配方及其印刷工艺,进一步制备出消光效果好、耐磨性好、抗返黏性优良、环保、手感舒适的触感型烟用接装纸产品。     

Theoretical investigation on nanoparticle concentrations in optoelectrofluidic chip based on diffusion,convection, and migration

A numerical model and simulation relative to an optoelectrofluidic chip has been presented in this article. Both dielectrophoretic and electroosmotic force attracting the nano-sized particles could be studied by the diffusion, convection, and migration equations. For the nano-sized particles, the protein with radius 3.6?nm is considered as the objective particle. The electroosmosis dependent upon applied frequency is calculated, which range 10²?Hz from 10⁸?Hz, and provides the much stronger force to enrich proteins than dielectrophoresis (DEP). Meanwhile, the induced light pattern size significantly affecting the concentration distribution is simulated. In this end, the concentration curve has verified that the optoelectrofluidic chip can be capable of manipulating and assembling the suspended submicron particles.     

Friction welding of TiAI intermetallics and structural steel by applying Inconel 718 as interlayer

Inconel 718 with thickness ranged from 0. 1 - 1.7 mm was chosen as interlayer to promote weldability in friction welding of TiAl intermetallics and structural steel such as AIS14140, in which the welded joint presents single fin showing less welding deformation on TiAl side. The correlations between tensile strength and the interlayer thickness were analyzed and fitted to a model. It indicates an optimum interlayer thickness ranged from 0.9 - 1.1 mm where the tensile strength reaches as high as 360 MPa. Otherwise, while the interlayer thickness decreases to 0. 1 mm, brittle compounds of TiC, Al2Ti4C2 and MTC3 are formed in the welded zone so that the tensile strength decays. Thicker interlayer should be also avoided as double joints may occur at TiAl -lnconel 718 and lnconel 718 -AISI 4140, respectively, which lowers the tensile strength to some extent.     

大规格钛-钢复合板的制备及性能

采用爆炸焊接技术制备尺寸为4260 mm×4260 mm×(6.5+32) mm的钛-钢复合板。采用超声波无损检测、相控阵波形显微镜、金相显微镜和扫描电子显微镜对复合材料板材的力学性能和界面形态进行分析。结果表明,当爆速、密度、炸药高度和间隔距离分别为2200~2270 m/s、0.80~0.82 g/cm³、45.0~46.0 mm和8.0~11.0 mm时,制备出的板材各项力学性能满足技术指标ASTM B898-2020。界面的波形为典型波纹状结合,界面清晰均匀,波形在漩涡区存在少量熔化,波幅和波长的比值为0.15~0.25,且在比值为0.2左右时,产品的剪切强度最高。本研究为大规格钛-钢复合板的制备提供工艺方法,并发现大规格钛-钢复合板的界面特点,为后续优化复合板爆炸焊接工艺提供理论指导。     

激光改性对YSZ涂层结构与性能的影响

本文采用电子束物理气相沉积技术在Ni基单晶基体表面制备双层结构的热障涂层后,采用脉冲Nd:YAG激光对其进行激光表面改性处理,获得具有复合陶瓷层结构的热障涂层。然后,对改性前后试样进行了1100℃高温氧化处理,并采用SEM和XRD分析了激光改性对涂层微观形貌和组织结构,以及抗氧化性能和耐腐蚀性能的影响。结果发现：激光改性处理后,试样表面形成致密平整的重熔层组织,该组织与原柱状晶组织共同构成了复合结构的陶瓷层,复合结构的陶瓷层减缓了有害元素向基体的扩散行为,提高了涂层的抗氧化性能和耐腐蚀性能。