Dense and core-rim structured B4C-TiB2 ceramics with Mo-Co-WC additive

B₄C-TiB₂ ceramics (TiB₂ ranging 5~70 vol%) with Mo-Co-WC as the sintering additive were prepared by spark plasma sintering. In comparison with B₄C-TiB₂ without additive, the enhanced densification was evident in the sintered specimen with Mo-Co-WC additive. Core-rim structured grain was observed around TiB₂ grains. The interface of the rim between TiB₂ and B₄C phases demonstrated different feature: the inner borderline of the rim exhibited a smooth feature, whereas a sharp curved grain boundary was observed between the rim and the B₄C grain. The formation mechanism is discussed: the epitaxial growth of (Ti,Mo,W)B₂ rim around the TiB₂ core may occur as a result of the solid solution and dissolution-precipitation between TiB₂ phase and the sintering additive. It was revealed that the fracture toughness increased as the content of TiB₂ content increased, alongside the decreased hardness. B₄C-30 vol% TiB₂ specimen demonstrated the optimal combination of mechanical properties, reaching Vickers hardness of 24.3 GPa and fracture toughness of 3.33 MPa·m^1/2.     

SDC-SCFZ dual-phase ceramics: Structure,electrical conductivity,thermal expansion,and O2 permeability

New CO₂-resistant dual-phase Sm_0.2Ce_0.8O_1.925–SrCo_0.4Fe_0.55Zr_0.05O_3-δ (SDC-SCFZ) ceramics present a promising outlook for potential future applications in membrane reactors and solid oxide fuel cells. Their high oxygen permeation flux and stability in CO₂ sweep gas also allow their integration in oxyfuel combustion. Here the structural characteristics, electrical conductivities, thermal expansion behaviors, and oxygen permeabilities of four different SDC-SCFZ membranes with weight ratios of 10:90, 25:75, 50:50, and 75:25 (SDC:SCFZ) are systematically studied. Among these four SDC-SCFZ compositions, 0.6 mm-thick 25 wt% SDC-75 wt% SCFZ displayed the highest oxygen permeation fluxes that reach 1.26 mL min⁻¹ cm⁻² at 950°C and retained its phase integrity under alternating He and CO₂ sweep gas over 72 hours of operation. This composite also showed a moderate thermal expansion coefficient of 1.90 × 10⁻⁵ K⁻¹ between 30°C and 1000°C and an electrical conductivity of at least 16 S cm⁻¹ at 550°C and above. Modeling studies revealed that the oxygen permeation fluxes through 25SDC-75SCFZ are limited by surface exchange reactions from 700°C to 800°C and mixed bulk diffusion and surface exchange reactions above 800°C.     

Dry Fractionation Approach in Concentrating Tocopherols and Tocotrienols from Palm Fatty Acid Distillate: A Green Pretreatment Process for Vitamin E Extraction

Palm fatty acid distillate (PFAD) is a rich source of vitamin E. As compared to other vegetable oil, PFAD has higher tocotrienol (70–80%) over tocopherol content, which makes it a valuable source for vitamin E extraction. Current vitamin E extraction methods are not sustainable due to the intensive usage of chemical and high operational cost. Hence, the present study investigated for the first time using dry fractionation process as a green and economical pretreatment method for separating solid fraction (stearin) and liquid fraction (olein) in order to concentrate vitamin E from PFAD in olein fraction. We examined the dry fractionation conditions: crystallization ending temperature (36–44 °C), cooling rate (0.3 and 1.5°C min⁻¹), stirring speed (20–125 rpm), and holding time (0–60 min) on the composition of unsaturated and saturated fatty acids as well as vitamin E content in liquid fraction (olein) and solid fraction (stearin) using gas chromatography and high performance liquid chromatography, respectively. In most of these conditions, vitamin E was ultimately higher in olein fraction as compared to stearin fraction, which is correlated with the high degree of unsaturation. Under a cooling rate of 0.3°C min⁻¹, 90 rpm stirring speed, and ending crystallization of 38 °C, the highest vitamin E rich olein fraction was attained with 1479 ± 10.51 ppm in 50 g olein fraction as compared to 1366 ± 7.94 ppm in 500 g of unfractionated PFAD.     

稀土对ZA27合金阻尼性能的影响

研究了稀土对ZA27合金阻尼性能的影响规律。结果表明：稀土变质可提高ZA27合金的阻尼性能，经稀土变质后的试样，其内耗是未变质的试样的1．4倍。ZA27合金为发挥其阻尼作用，在频率高于70Hz时，效果明显，且经稀土变质后的试样强迫振动衰减效果比未变质的试样强。     

船舶柴油机主控装置

本文详细介绍了一种船舶柴油机主控装置的功能，结构、工作原理以及软件设计等，经现场调试和海上实验，主控装置完全满足设计和应用的要求。     

SIEMENS FM357多轴驱动模块在铸咀布流控制系统中的应用研究

本文介绍了SIEMENS FM357多轴驱动模块的特点及在超薄快速铸钇铸咀布流控制系统中的应用，并对FM357的参数调协、各功能模块及数据模块的应用做了阐述。     

T形接头细丝埋弧自动焊工艺的研究及应用

针对整体节点钢桥桁梁对T形对接接头的焊接质量的高要求，研究推荐了一种细丝埋弧自动焊的工艺方法。与常用的手工电弧焊工艺相比，其焊缝成形美观、质量优良，焊接生产效率高，已成功地应用于钢梁焊接制造中。     

Studying the formation process of chromate conversion coatings on aluminium using continuous electrochemical noise resistance measurements

A unique electrochemical technique, namely continuous noise resistance calculation (CNRC), was used to obtain electrochemical kinetic information from the formation process of chromate conversion coatings (CCC) on aluminium electrodes. It was found that the noise resistance (R_n) of aluminium electrodes remained almost unchanged during electrodes' immersion in a chromate containing acidic solution where the CCC films were supposed to form rapidly. This result indicates that the formation of CCC was associated with continuous corrosion of the aluminium electrodes and that the CCC films formed on aluminium surface were not intact barrier films, but most likely porous layers. The CCCs became protective only after they were aged in the environment. Based on these findings, the formation and inhibition mechanisms of CCC have been discussed.