Effect of Nb2O5 content and sintering temperature on the microstructure and bending strength of porous Ni-YSZ cermets

Porous Ni-YSZ cermets are prepared by reducing NiO-YSZ composites upon exposure to (Ar+6% H₂) gas. The porous cermets are prepared by the addition of carbon black (0.123 mol) to mixed NiO-YSZ powders and the conversion of NiO to Ni in the NiO-YSZ composites. The microstructure and bending strength of porous Ni-YSZ cermets as functions of sintering temperature and Nb₂O₅ content are discussed. The Ni-YSZ cermets consist of uniformly distributed Ni and YSZ grains as well as pores. Both higher sintering temperature and higher Nb₂O₅ content yield lower porosity, thus increasing the bending strength. The bending strength of 0.00470 mol% Nb₂O₅–containing Ni-YSZ cermets sintered at 1400 °C (111 MPa) is about two times higher than that of Nb₂O₅–free Ni-YSZ cermets sintered at 1400 °C (59 MPa).     

A simple non-destructive method to indicate the spallation and damage degree of the double-ceramic-layer thermal barrier coating of La2(Zr0.7Ce0.3)2O7 and 8YSZ:Eu

Double-ceramic-layer (DCL) thermal barrier coatings (TBCs) of La₂(Zr_0.7Ce_0.3)₂O₇ (LZ7C3) and Eu³⁺-doped zirconia, which was partially stabilised by 8 wt% yttria (8YSZ:Eu), were prepared by atmospheric plasma spraying. A thermal cycling test was carried out. The 8YSZ:Eu sublayer exposed during thermal cycling could produce visible luminescence under ultraviolet (UV) illumination, providing an indication of the spallation and damage degree of the coating. The result shows that the application of a Eu³⁺-doped luminescence sublayer can be a very simple and useful non-destructive technique to indicate the spallation and damage degree of DCL coatings.     

Study on the gaseous and electrochemical hydrogen storage properties of as-milled CeMgNi-based alloys

For gaining further insight into the involvement of the gaseous and electrochemical hydrogen storage properties of CeMg₁₂-type alloys, partial substitution and ball milling were both used to synthesize the nanocrystalline and amorphous CeMg₁₁Ni + x wt.% Ni (x = 100, 200) samples. This research aims at elucidating the functional roles of Ni content and milling time on samples' structure and hydrogen storage performance. X-Ray diffraction and high-resolution transmission electron microscope were used to reveal the micro constructions of alloys. To determine the gaseous hydrogen storage property, Sievert's apparatus and a thermal gravity analysis bonded with a H₂ probe were adopted. The dehydrogenation activation energy was computed in the Kissinger method. The electrochemical performances of the as-milled samples were measured through a constant current system. Further researches showed that the electrochemical performance of as-milled samples had been dramatically improved by increasing Ni content. With milling duration lengthens, the gaseous hydrogen absorption capacity, gaseous hydriding rate and high rate discharge capability of samples reached the maximal values, but electrochemical discharge capacity and gaseous dehydriding rate always increased. The dehydrogenation activation energy decrease resulted by improving Ni percent and milling duration was deemed as the cause of the excellent gaseous kinetics of samples.     

Poly(N-vinyl-2-pyrrolidone)-stabilized ruthenium supported on bamboo leaf-derived porous carbon for NH3BH3 hydrolysis

In this work, poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium nanoparticles (NPs) supported on bamboo leaf-derived porous carbon (Ru/BC) has been synthesized via a one-step procedure. The structure and morphology of the as-synthesized samples were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectrometry (XPS), scanning electron microscope (SEM) and transmission electron microscope (TEM). As a catalyst for hydrogen generation from the hydrolysis of ammonia-borane (AB, NH₃BH₃) at room temperature, Ru/BC stabilized with 1 mg of PVP exhibited high activity (TOF = 718 mol_H2·mol_Ru⁻¹·min⁻¹) and low activation energy (E_a = 22.8 kJ mol⁻¹). In addition, the catalyst could be easily recovered and showed fairly good recyclability with 55.6% of the initial catalytic activity retained after ten experimental cycles, which confirmed that PVP could stabilize the Ru NPs and prevent their agglomeration on BC surface. Our results suggest that PVP-stabilized Ru/BC is a highly efficient catalyst for the hydrolysis of AB.     

1,3,5-苯三甲酸衍生物类新型成核剂的合成及应用研究

合成了新型成核剂1,3,5-苯三甲酸三（环己胺）（BTCA-TCHA）,研究了该成核剂对等规聚丙烯力学性能、结晶行为和熔融行为的影响。结果表明,成核剂BTCA-TCHA可明显改善等规聚丙烯的力学性能和光学性能,并可以大幅度提高结晶峰温度。当BTCA-TCHA添加量为0.2 %时,等规聚丙烯的拉伸强度和弯曲模量可分别提高9.72 %和12.4 %,雾度降低53.5 %。当降温速率为20 ℃/min时,添加BTCA-TCHA的等规聚丙烯的结晶峰温度可从空白样的114.6 ℃提高到126.8 ℃。BTCA-TCHA的性能与传统的山梨醇类成核剂Millad 3988基本接近。     

无麸质大米面包研究进展

开发大米面包不但可以丰富中国大米类产品的花色品种,还能解决麸质过敏人群对饮食多样化的需求。由于无麸质大米面包中不含面筋蛋白,在制作过程中存在面团难以形成有效的网络结构、不易成型、品质差(持水性、持气性、弹性和内聚性)、老化速率快等缺点。近年来,研究人员通过改进工艺条件、添加品质改良剂等方法,对无麸质大米面包品质进行改善,文章简述了无麸质食品的相关标准和大米面包使用的原料,并介绍了其工艺和品质改良研究进展,以期为无麸质大米面包的产业化开发提供参考。     

淀粉基膜的制备及应用研究进展

淀粉是除纤维素外的第二大可再生原料,淀粉基膜绿色环保、安全无毒、可生物降解,缓解了合成材料的不可降解对生存环境的污染和原料日益枯竭的压力,实现资源的可持续发展,是当今最具有发展前景的新型材料之一。文章对淀粉基膜的制备方法进行了综述,介绍了湿法、干法制备淀粉基膜及其物理化学性质,阐述了淀粉基膜在食品保鲜、包装等领域的应用,并对淀粉基膜的应用前景进行展望。     

不同热处理对籼米及其半干粉品质的影响

为考察不同热处理对籼米籽粒及其半干粉品质的影响,采用不同条件热处理籼米籽粒,分析米粒表观裂缝增加程度与其内部水分的关系,并进行半干法制粉(含水率为30%),测定不同热处理对大米粉微生物、破损淀粉及白度的影响。结果表明,热处理后的米粒,表观裂缝开始明显增加时米粒内部水分均小于8%;3种热处理(60℃90 min,120℃15min及180℃1min)后的大米调制粉微生物被有效抑制,且超高温短时(120℃15min,180℃1min)抑菌效果优于低温长时(60℃90min),破损淀粉、白度及糊化特性与干磨粉差异显著(P0.05),更接近湿磨粉。通过测定米粒内部水分可判断米粒表观裂缝增加的程度,且热处理大米籽粒进行半干法制粉其粉质特性与湿磨粉相当。     

大豆分离蛋白、木薯淀粉与转谷氨酰胺酶组合对鲢鱼鱼糜凝胶品质的影响

探究了大豆分离蛋白、木薯淀粉及转谷氨酰胺酶对鲢鱼鱼糜制品的影响并确定最适添加量。结果表明,当大豆分离蛋白添加量6%,木薯淀粉添加量9%以及转谷氨酰胺酶添加量4U/g·蛋白时,能有效增加鱼糜的持水性,降低其蒸煮损失,且不会使鱼糜带有大豆分离蛋白的淡黄色,同时提高了鱼糜的凝胶强度,鲢鱼鱼糜制品各项指标较好。通过低场核磁共振和扫描电镜检测发现,未添加的对照组在6次冻融后凝胶结构完全被破坏,不易移动水峰面积(A_(23))下降了25%,试验组凝胶结构比较致密,A_(23)下降了11%,进一步验证了此配方组合对鱼糜在冻融循环过程中凝胶结构的稳定性具有保护作用。