为提高石墨/CaF2/TiC/镍基合金(GCTN)复合涂层的力学性能和摩擦学性能,运用等离子喷涂技术在45钢表面制备了Y2 O3改性GCTN复合涂层,研究了Y2 O3对复合涂层的微观组织、显微硬度、断裂韧性和摩擦磨损性能的影响。结果表明：Y2 O3改性 GCTN 复合涂层主要由γ-Ni、CrB、Cr7 C3、TiC、CaF2和石墨等物相组成。Y2 O3在等离子火焰加热作用下与 C 元素反应生成活性元素 Y,Y 净化了复合涂层的微观组织,并细化了 CrB、Cr3 C7等硬质相晶粒,提高了其致密性。当 Y2 O3质量分数为0.5％时,复合涂层的显微硬度和断裂韧性分别为593.3 MPa和6.82 MPa·m1/2,比不含 Y2 O3的复合涂层分别增大了8％和22％,其机理主要是Y2 O3细化了 CrB、Cr3 C7等硬质相晶粒,起到了细化强化作用。由于GCTN-0.5Y2 O3复合涂层的显微硬度和断裂韧性显著提高,减少了其黏着磨损和微观断裂磨损,因而GCTN-0.5Y2 O3复合涂层的摩擦因数和磨损率最小,分别为0.085和0.39×10-3 mm3/m。

In order to improve the friction and wear properties,the graphite/CaF2/TiC/Ni-base al-loy(GCTN)composite coatings were modified Y2 O3 and prepared by plasma spray on the surface of 45 carbon steel.The microstructure,microhardness,fracture toughness and tribological properties of the composite coatings were researched.The results show that the Y2 O3 modified GCTN composite coatings are mainly composed ofγ-Ni,CrB,Cr7 C3 ,TiC,CaF2 and graphite.Y2 O3 reacts with C and produces active element Y by the heat of plasma flame.Y can purify theγ-Ni structure,refine the grain size of CrB and Cr3 C7 ,and improve the density of the composite coating.When Y2 O3 is 0.5wt%,the microhardness and fracture toughness of the composite coating are 593.3 MPa and 6.82 MPa·m1/2 respectively,which are increased by 8% and 22% than those of the composite coating without Y2 O3 ,because of the refining strengthening effort of CrB and Cr3 C7 .The improvement of microhardness and fracture toughness of the

采用高温熔融法制备了中温固体氧化物燃料电池用系列硼硅酸盐玻璃,玻璃摩尔组成为40SrO-5La2O3-xAl2O3-(25-x)B2O3-30SiO2(x=0,2.5,5.0,10.0)。结果表明:随着Al2O3含量的逐渐增多,玻璃转变温度和析晶峰温度逐渐升高,而热膨胀系数(CTE)均在9.8×10-6/K左右,这与电极材料8%(摩尔分数)Y2O3稳定ZrO2(8YSZ)在相同温度范围内的CTE相接近。Al2O3摩尔含量为5%的硼硅酸盐玻璃在700℃热处理100h后未能检测到明显的析晶和CTE变化,同时与8YSZ电极材料在700℃保温100h没有观测到明显的界面反应,表明该玻璃具有良好的化学相容性。

A series of glasses with the molar compositions of 40SrO-5La2 O3-xAl2 O3-(25-x)B2 O3-30SiO2 (x=0,2.5,5.0, 10.0)were fabricated by a melt-quenching method as intermediate temperature solid oxide fuel cells (ITSOFC).The results show that glass transition temperature (Tg )and peak temperature of crystallization (Tp )increase gradually and the coefficients of thermal expansion (CTE)is 9.8×10-6/K,which is similar to the CTE of 8%(in mole)Y2 O3-stabilized ZrO2 (8YSZ)electro-lyte in the same temperature range.After heat treatment at 700℃ for 100 h,no evident X-ray diffraction (XRD)peaks appear, and little change of the CTE occurs for the glass sample with 5% Al2 O3 .After reaction with 8YSZ at 700 ℃ for 100 h,no in-terfacial reaction occurs,indicating that the glass sample is chemically compatible with 8YSZ electrolyte.

采用溶胶-凝胶法制备了AlO1.5掺杂浓度为0.5%,1.0%,2.0%的AlO1.5/Ce0.8Gd0.15Y0.05O2-δ固体电解质材料,利用X射线衍射(XRD)、扫描电子显微镜(SEM)和交流阻抗谱研究了Al2O3掺杂对Ce0.8Gd0.15Y0.05O2-δ微观结构及电性能的影响,结果表明:800℃焙烧的所有粉末样品均为单相立方萤石结构,在所有样品中,AlO1.5掺杂量为0.5%的样品晶粒均匀,较致密,交流阻抗谱测试表明掺杂AlO1.5(x=0.5%)使Ce0.8Gd0.15Y0.05O2-δ晶界电阻减小,晶界电导率增高;当AlO1.5掺杂量x≥1%时,Al2O3对晶界的阻塞作用使晶界电导率降低,在所有样品中Ce0.8Gd0.15Y0.05O2-δ/0.5%AlO1.5晶界电导率最高(σ700℃=8.12×10-3S/cm),说明在Ce0.8Gd0.15Y0.05O2-δ少量掺杂AlO1.5(x=0.5%)具有烧结助剂和晶界清除剂的作用.

AlO1.5/Ce0.8Gd0.15Y0.05O2-δ solid electrolytes,with AlO1.5 concentrations ranging from 0. 5% to 2%were prepared by sol-gel method. The effects of AlO1. 5 doping on the microstructure and conductivity were discussed by means of X-ray diffraction ( XRD ) , scanning electron microscopy ( SEM ) and AC impedance spectroscopy. The results show that all powders calcined at 800℃ are crystallized in a single cubic fluorite structure. The sample doping with 0. 5% AlO1. 5 is more uniform and relative dense. AC impedance spectra analysis suggests that AlO1.5(x=0. 5%)make the grain boundary resistance of Ce0.8Gd0.15Y0.05O2-δdecrease and the grain boundary conductivity increase. When AlO1. 5 dopant concentration is over 1%, the grain boundary conductivity begins to reduce because of blocking effect of AlO1. 5 particles at grain boundaries in all samples. The grain boundary conductivity of AlO1. 5/ Ce0. 8 Gd0. 15 Y0. 05 O2-δ reaches the maximum,σ700℃ =8. 12 × 10-3 S/cm, which suggest

以H2O2诱导SH-SY5Y细胞氧化损伤为模型,探讨没食子酸(gallic acid,GA)对H2O2诱导SHSY5Y细胞氧化损伤的保护作用及其机制。方法:CCK-8法筛选没食子酸对SH-SY5Y细胞无毒剂量范围,在此剂量范围研究没食子酸对H2O2诱导SH-SY5Y细胞氧化损伤的影响。将细胞分为5组:正常对照组(Control),H2O2模型组(Model),GA 5μmol·L-1组(GA1)、GA 10μmol·L-1组(GA2)和GA 25μmol·L-1组(GA3)。GA组先加入GA预处理1 h后再加入终浓度为200μmol·L-1的H2O2。Hoechst 33258染色观察凋亡细胞的形态学特征;碘化丙啶染色流式细胞仪检测细胞周期构成比;Diaphorase催化的INT显色反应检测乳酸脱氢酶(lactate dehydrogenase,LDH)释放量;DCFH-DA检测细胞内活性氧(reactive oxygen species,ROS)含量;利用天冬氨酸蛋白水解酶-3(caspase-3)可以催化底物Ac-DEVD-pNA的反应检测caspase-3活性。结果:与正常对照组相比,终浓度为200μmol·L-1的H2O2作用于SH-SY5Y细胞24 h后,细胞活力下降至65%(P0.01),细胞凋亡率显著上升(P0.01);出现了明显的细胞凋亡形态学特征;增殖指数(proliferation index,PI)明显降低(P0.05);LDH释放量和细胞内ROS含量显著增加(P0.01),caspase-3活性明显增强(P0.01)。与H2O2组相比,终浓度为5~25μmol·L-1GA能显著改善上述指标的变化(P0.05)。结论:GA在一定剂量范围内对H2O2诱导的SH-SYSY细胞损伤具有明显的保护作用,其保护效应可能与清除ROS,减轻DNA氧化损伤,抑制线粒体介导的细胞凋亡有关。

Objective:This study examined the neuroprotective effects of GA on SH-SY5Y cells injured by H2O2 and the molecular mechanisms underlying these neuroprotective effects. Methods:CCK-8 assay was performed to determine the non-toxic dose range of gallic acid in SH-SY5Y cells. Cultured human neuroblastoma SH-SY5Y cells were subjected to oxidative damage with H2O2 in the presence and absence of non-toxic doses of GA. The growth of the cells was analyzed by plotting the cell growth curves and by CCK-8 assay. The cell morphological changes were observed by inverted optical microscope. Typical morphological features of apoptotic cells were detected using Hoechst 33258 staining. FCM was used to analyze cell cycle alteration using propidium iodide staining;the release rate of LDH was determined by diaphorase-INT reaction. ROS production was determined by DCFH-DA fluorescence. Caspase-3 activity was determined by its capacity to catalyze the substrate Ac-DEVD-pNA. Results:H2O2 treatment produced d

以硫酸铝为铝源、碳酸氢铵为沉淀剂,采用分步老化法,使用L9(34)正交实验考察了碳酸氢铵物质的量浓度、反应温度、pH和n(HCO-3)/n(Al 3+)等因素对制备γ-Al2O3的影响,并对所得Al2O3进行了N2物理吸附表征和堆积密度测量,对Y5样品进行了X射线衍射和电镜扫描,由正交实验结果分析得出温度和pH对γ-Al2O3的结构影响很大。大孔容氧化铝的制备最佳条件为:反应温度为75℃,pH为8.5,碳酸氢铵物质的量浓度为2mol/L,n(HCO-3)/n(Al 3+)为0.75。其中,样品Y5孔容达2.02mL/g,具有双峰孔分布,粒子呈纤维状,大小均匀,粒径为1μm左右。

Alumina were prepared with aluminium sulfate as aluminium source,ammonium bicarbonate as precipitant,using substep aging method and L9 (34 ) orthogonal table.Factors inculding ammonium bicarbonate concentration, reaction temperature,pH and n(HCO-3 )/n(Al3+)were studied.The alumina were characterized by the N2 physisorption and bulk density measurement,XRD and SEM as well.After orthogonal analysis,reaction temperature and pH have significant effect on textile properties ofγ-Al2 O3 .Optimum preparation conditions were determined by macropore formation,and they were as follows:reaction temperature 75 ℃,pH 8.5,the concentration of ammonium bicarbonate 2 mol/L,n(HCO-3 )/n(Al3+)ratio 0.75.Besides that,Y5 has big pore volume up to 2.02 mL/g,bimodal pore distribution and fibrous particles which have uniform size around 1μm.