等离子喷涂-物理气相沉积涡轮叶片7YSZ热障涂层

以纳米团聚的氧化钇稳定氧化锆(7YSZ)粉末为原料,通过等离子喷涂-物理气相沉积(PS-PVD)技术在涂覆有NiCoCrAlY粘结层涡轮叶片表面制备了羽毛柱状热障涂层,对不同部位涂层的微观结构进行表征.结果表明:PS-PVD技术在涡轮叶片上不同部位制备的热障涂层结构相同,能够在非视线沉积区域的叶缘板表面获得典型的PS-PVD热障涂层结构.涂层沉积过程中,涡轮叶片构型对涂层沉积效率有明显影响,当喷枪垂直叶片旋转轴时,涂层在远离叶片旋转轴区域的厚度较低,原因在于凹型曲面对反射粒子具有汇聚作用而凸型曲面对粒子具有分散作用,两种因素结合可预测复杂构型叶片表面的涂层厚度分布规律.PS-PVD技术制备的热障涂层具有良好的抗热震性能,采用涂层表面镀铝改性工艺能减缓循环热应力造成的涂层失效.     

六盘水市煤炭行业竞争战略分析

我国是富煤贫油少气的国家,煤炭是我国最重要的一次能源。但从能源激烈的竞争市场环境而言,当前我国煤炭行业发展出现了困境。为了更好地发展六盘水地区的煤炭行业,结合竞争战略理论和六盘水市的煤炭行业发展状况,运用PEST分析法和波特五力模型对六盘水市煤炭行业进行分析,得出整合资源,结合自身优势大力吸引人才,最终达到产业转型的生态化煤炭发展战略模型。分析结果可为提高六盘水煤炭行业竞争力提供理论支持。     

Oxygen concentration measurement and control of lead-bismuth eutectic in a small,static experimental facility

ABSTRACT

Oxygen measurement and control system is critical for minimizing corrosion in nuclear systems. Oxygen measurement and control tools use lead-bismuth eutectic (LBE) and pure lead as a coolant or as a spallation target. Oxygen can be supplied by either gas phase (H₂O or O₂) or solid phase (PbO dissolution); thus, oxygen control includes both gas phase and solid phase methods. This article focuses on oxygen concentration measurement and control of lead-bismuth eutectic in a small, static experimental facility. This facility was developed for oxygen sensor calibration and gas/solid phase control systems test programs. The oxygen sensor with Nano Cu/Cu₂O closely the Nernstian behavior down to 195°C; the oxygen sensor measurement accuracy satisfied the requirements of subsequent experiments. The gas phase control system (verified according to different type of mass transfer, such as air, H₂O, gas injection, and coverage) and the solid phase control system were very successful in small experimental devices. Accurate oxygen concentration control was achieved with both the gas and solid phase control systems.     

国内在役核电厂首例电气贯穿件更换改造

核电厂电气贯穿件作为安全壳上的关键设备,承担着核岛内外各种电力和信号传输以及保证安全壳压力边界完整性的重要功能。通过秦山核电厂一期工程30万千瓦机组第18次大修期间国产在役DDG-1型电气贯穿件更换改造项目的实施,分析了秦山核电厂一期工程在役电气贯穿件设备现状和改造的必要性;针对在役核电厂更换改造工期短和贯穿件密封性能验证难等问题,通过优化检验工序、制作专用检漏工装的方法,缩短了贯穿件改造的工期并验证了贯穿件密封性能。      

Flame Retardancy and Mechanical Properties of Bio‐Based Furan Epoxy Resins with High Crosslink Density

This work outlines an interesting approach to bioepoxy resins from sustainable 2,5‐bis((oxiran‐2‐ylmethoxy)methyl)furan (BOF). The 3,3′‐diamino diphenyl‐sulfone (33DDS) and 4,4′‐diamino diphenyl‐sulfone (44DDS) are employed as hardeners. For comparison, petro‐based networks from diglycidyl ether of bisphenol A (DGEBA) are developed as well. The systematic analyses suggest that the BOF/DDS networks show higher crosslink densities and mechanical properties than DGEBA/DDS thermosets. Remarkably, an attractive multilayer tubular microstructure is fabricated in the BOF/44DDS thermosets, and it greatly enhances the mechanical performance. Apart from that, BOF/DDS composites exhibit excellent flame retardancy. Especially, for BOF/44DDS, the self‐extinguishment happens in 7 s. The fire retardant mechanism confirms that a low heat release rate and heat release capacity as well as a compact char layer occur in the pyrolysis of BOF/DDS. Thus, the BOF/DDS exhibits superior performance over its DGEBA counterparts and meets a wide variety of requirements in engineering.     

Catalytic oxidative desulfurization of gasoline using phosphotungstic acid supported on MWW zeolite

Catalysts for the desulfurization of gasoline samples were synthesized via the immobilization of well-dispersed phosphotungstic acid (HPW) on Mobil composition of matter-twenty-two (MWW) zeolite. Characterization results indicated that these catalysts possess a mesoporous structure with the retention of the Keggin structure of immobilized HPW. Relevant reaction parameters influencing sulfur removal were systematically investigated, including HPW loading, catalyst dosage, temperature, initial S-concentration, molar ratio of oxidant to sulfide (O/S), volume ratio of MeCN to model oil (Ext./oil), and sulfide species. The 40 wt-% HPW/MWW catalyst exhibited the highest catalytic activity with 99.6% dibenzothiophene sulfur removal from prepared samples. The 40 wt-% HPW/MWW catalyst was recycled four times and could be easily regenerated. Finally, as an exploratory study, straight-run-gasoline and fluid catalytic cracking gasoline were employed to accurately evaluate the desulfurization performance of 40 wt-% HPW/MWW. Our research provides new insights into the development and application of catalysts for desulfurization of gasoline.     

The effects of thermoresponsive microgel density on cell adhesion,proliferation, and detachment

In recent years, poly(N-isopropylacrylamide)-based microgels have been emerged as a new thermoresponsive coating for cell/cell sheet harvesting, yet few work reports their effect on cell attachment, morphology, activity, and proliferation in details. In this work, poly(N-isopropylacrylamide-co-styrene) (pNIPAAmSt) microgel was selected as the model to study its density on NIH3T3 cell adhesion, morphology, activity, and detachment. Results showed that 0.5 wt % pNIPAAmSt microgel density leads to more cells adhesion, higher cell activity yet lower cell proliferation. Moreover, cell adhesion location can be well controlled either by manipulating the sub-cellular scale distances between microgels or by fabricating large scale surface patterns of the microgels on higher microgel density. By temperature stimuli, similar ratio cells detached from the microgel density surface from 0.5 to 1.5 wt %. The results in this article are worthy for the application of thermoresponsive microgels in cell regulation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48773.     

Morphology and properties of HDPE/zinc-neutralized sulfonated EPDM blends

The compatibility of zinc-neutralized sulfonated EPDM (Zn-SEPDM) and its effect on crystallizing behavior of high-density polyethylene (HDPE) as well as the morphology of the blend were studied through wide-angle X-ray diffractomer (WAXD), differential scannign calorimetry (DSC), transition electron micrography.(TEM), scanning electron micrography (SEM), a capillary rheometer, and mechanical property test. The results show that addition of Zn-SEPDM decreases both the melting point and the crystallizing temperature of HDPE. The apparent viscosity of the blend decreases with increasing of shear rate and stress. As Zn-SEPDM content exceeds 20%, Zn-SEPDM in the blend becomes continuous and an abrupt change in impact strength occurs. Owing to the incorporation of ionic groups into EPDM, the strong interaction between the chains make the impact strength of HDPE incredibly increased without sacrificing much of its tensile strength.     

塑料基TiO2电致变色薄膜制备及性能研究

采用溶胶-凝胶法分别在镀有ITO透明电极的玻璃和塑料基体上制备了TiO2电致变色薄膜,对比研究了不同基体上溶胶的成膜性及薄膜的电致变色性能.结果表明:在相对湿度低于15%的环境中,采用0.4mol/L的溶胶可以通过多次提拉制得表面光洁的较厚透明TiO2薄膜;随热处理温度的升高,薄膜的电色可逆性变好,循环寿命变大,但离子储存能力下降;塑料基TiO2薄膜与相同条件下制备的玻璃基薄膜具有相似的性能,呈现出较弱的阴极电致变色效应和较强的Li 储存能力,有望用作柔性电致变色器件的对电极.     

芳纶Ⅲ纤维拉伸性能的实验研究

测试了芳纶Ⅲ纤维的拉伸性能等,并与F-12和Kevlar-49纤维进行了对比.对由芳纶Ⅲ纤维与环氧树脂基体复合成型的单向纤维增强环形试样,测试了其拉伸强度、弹性模量和层间剪切强度,结果表明:芳纶Ⅲ纤维单向纤维复合材料的拉伸强度和弹性模量与F-12纤维相当,分别比Kevlar-49纤维要高出约25.7%和24.7%;但早期的芳纶Ⅲ纤维与环氧树脂基体的界面结合性较差,层间剪切强度仅为32.0～35.2MPa.