Ce0.8Sm0.1Gd0.1O1.9电解质的制备及其性能研究

通过凝胶浇注法制备了Sm, Gd共同掺杂的CeO2(SGC)粉末, 将制得的粉末经1400 ℃高温烧结4 h得到相应的SGC电解质烧结体, 并对SGC粉末及相应的烧结体的性能进行了表征. 实验结果表明: 凝胶浇注法制备出了Sm, Gd共同掺杂的纳米CeO2粉末;所得粉末有良好的烧结活性, 1400 ℃下烧结所得电解质材料的相对密度大于94%. 电导率的测试表明, SGC电解质材料在中温范围有较高的电导率, 800 ℃时, 其电导率达到了0.082 S·cm-1, 有望成为中温固体氧化物燃料电池的电解质材料.     

稀土电解质Ce0.8Gd0.2O2-δ的制备与性能

采用共沉淀法制备了中温固体氧化物燃料电池（IT-SOFC）电解质材料Ce0．8Gd0．2O2-δ，并对其进行了性能测试。X射线测试表明，前驱体经1000℃煅烧后得到的粉末为单一的立方萤石结构。SEM测试表明煅烧温度对粉末形貌及烧结体致密度有重大影响，1350℃烧结后烧结体的相对密度能达到96．4％。同时高温阻抗谱表明，该电解质700℃时离子电导率为0．003 S／cm。     

用甘氨酸法合成Sm0.1Ca0.9MnO3粉体及热电性能表征

以Sm2O3、CaCO3、乙酸锰和硝酸为原料,采用改进的甘氨酸-硝酸盐法制备Sm0.1Ca0.9MnO3粉末,经过压制和烧结制备热电材料。用X射线衍射、扫描电镜和激光粒度仪等对粉末进行表征,并研究该热电材料的性能。结果表明,Sm0.1Ca0.9MnO3粉末为单一的钙钛矿相结构,粉末体为细小晶粒的团聚体,呈链状结构,粒度范围1.436~12.118μm。Sm0.1Ca0.9MnO3粉体的压形规律符合黄培云压制方程,压制模量M为1.124 7 MPa,非线性指数m为4.544 5;随着Sm3+的掺杂,Sm0.1Ca0.9MnO3材料的电阻率减小;随温度升高,发生半导体向金属的转变现象,在473 K时Sm0.1Ca0.9MnO3块体的功率因子达到6.0×10-4 W/(m-K2)。因此,Sm0.1Ca0.9MnO3是1种具有潜在应用前景的n型热电材料。     

自蔓延法制备Sm0.9Sr0.1CoO3粉体及其热电性能

本文采用自蔓延法制备了纯物相的Sm0.9Sr0.1CoO3(SSC)复合氧化物粉末,平均粒径为8.681 μm.对Sm0.9Sr0.1 CoO3粉末的模压数据进行处理,实验结果表明:Sm0.9 Sr0.1 CoO3陶瓷粉体的压形规律符合黄培云压制方程.同时,对Sm0.9Sr0.1CoO3烧结体的电导率和Seeback系数及热导率进行测量.结果表明,Sm0.9Sr0.1CoO3材料电导率和热导率随温度的升高而增加,而Seeback系数随温度的上升而降低;材料的电传输机理为小板子CoCo的跃迁;材料的无量纲优值ZT在300K时为0.026.     

Sm0.5-xGdxSr0.5CoO3-δ/30%Ce0.9Gd0.1O1.95复合阴极的制备及性能研究

采用固相反应法制备了中温固体氧化物燃料电池阴极材料Sm0.5-xGdxSr0.5CoO3-δ(SGSC),用溶胶-凝胶法制备了Ce0.9Gd0.1O1.95(GDC)电解质粉体。用X射线衍射仪、热膨胀仪及交流阻抗谱法分别对SGSC材料的结构、化学稳定性、热膨胀性质及SGSC/30%GDC阴极的电化学性能进行了研究。结果表明,经1100℃焙烧6 h的SGSC粉体均形成单相正交钙钛矿结构,SGSC与GDC电解质在高温下具有良好的化学相容性。随着Gd3+含量的增加,材料的热膨胀系数无规律性变化,极化电阻先减小后增加,在x=0.15时,以SGSC/30%GDC为复合阴极的极化电阻最小,750℃时,Rp=0.03Ω.cm2。     

中温直接碳氢化合物固体氧化物燃料电池Cu-CeO2-ScSZ阳极的研究

采用共沉淀法合成了氧化钪稳定氧化锆(9 mol%Sc2O3,ScSZ)粉末.应用热膨胀分析仪研究了ScSZ粉末的烧结特性,采用扫描电镜观察了烧结试样的微观组织,利用交流阻抗法测定了ScSZ电解质在500～900℃的电导率.制备了以ScSZ为电解质、Cu-CeO2一ScSZ为阳极、ScSZ-LSM为阴极的阳极支撑燃料电池.在700℃时,直接以氢气、丁烷和甲烷为燃料,测得的电池最大输出功率密度分别为280 mW/cm2、142 mW/cm2和120 mW/cm2.     

NASICON型固体电解质Li1.1Y0.1Zr1.9(PO4)3的SPS烧结及性能

采用溶胶-凝胶法合成NASICON型固体电解质Li_1.1Y_0.1Zr_1.9(PO₄)₃粉体.研究了不同烧结方式对Li_1.1Y_0.1Zr_1.9(PO₄)₃电解质的性能影响.通过差热分析仪分析前驱体的热性能,采用X射线衍射仪、扫描电子显微镜、交流阻抗仪对固体电解质的物相、结构及电化学性能进行表征.结果表明,溶胶-凝胶法成功制备出纯相的NASICON型Li_1.1Y_0.1Zr_1.9(PO₄)₃,并且颗粒均匀;相比传统的无压烧结,SPS烧结明显提高了样品致密度(致密度达94.38 %),室温离子电导率高达8.99×10-5 S/cm.      

草酸共沉淀制备超细Ce0.8Sm0.2O1.9工艺优化

掺杂铈基电解质由于具有高电导率用于中温固体氧化物电解质材料.实验采用草酸盐共沉淀法制备20%(摩尔分数)Sm2O3掺杂CeO2(Ce0.8Sm0.2O1.9)氧化物粉末,采用XRD、SEM分析粉末的相结构和颗粒形貌,500℃～1000℃煅烧草酸沉淀物,得到氧化物粉末.XRD分析结果表明,Ce0.8Sm0.2O1.9为立方萤石结构,表明在低温合成了纯相的Sm2O3掺杂CeO2固溶体.激光粒度分析仪分析沉淀反应过程中草酸盐沉淀物和氧化物粉末的粒度分布.通过优化沉淀反应pH值、溶液浓度、添加表面活化剂及沉淀物水洗和干燥处理等制备工艺条件,实现对沉淀反应过程中草酸沉淀物的团聚控制,得到分散良好的亚微米草酸共沉淀物,进一步选择合适煅烧温度,得到亚微米级超细Ce0.8Sm0.2O1.9粉末.     

ZrO_2－Y_2O_3超细粉末的研制

以ＺｒＯ２－Ｙ２Ｏ３超细粉末为研究对象，通过Ｘ射线衍射、差热分析（ＤＴＡ）、透射电镜和扫描电镜观察等方法，对共沉淀法制备的超细粉末进行了物相、粒度分析，并对该粉料压形烧结后进行了组成、密度、显微结构的测试分析。探讨了分散剂、盐溶液浓度、ｐＨ值、灼烧温度等条件对粉末烧结性能的影响，对用分散剂代替无水乙醇脱水工艺控制粉末团聚体做了研究尝试，得出了制备超细粉末的最佳工艺条件并制得了粒度为２０ｎｍ的ＺｒＯ２－Ｙ２Ｏ３超细粉。     

中温直接碳氢化合物固体氧化物燃料电池Cu—CeO2-ScSZ阳极的研究

采用共沉淀法合成了氧化钪稳定氧化锆（9mol％Sc2O3,ScSZ）末。应用热膨胀分析仪研究了ScSZ粉末的烧结特性,采用扫描电镜观察了烧结试样的微观组织,利用交流阻抗法测定了ScSZ电解质在500-900℃的电导率。制备了以ScSZ为电解质、Cu—CeO2-ScSZ为阳极、ScSZ—LSM为阴极的阳极支撑燃料电池。在700℃时,直接以氢气、丁烷和甲烷为燃料,测得的电池最大输出功率密度分别为280mW/cm^2、142mW／cm^2和120mW/cm^2。     

单晶型LiNi0.8Co0.1Mn0.1O2正极材料的制备及性能对比

基于高镍三元正极材料容量和成本等方面的优异性,通过熔盐法结合高温固相法进行梯度煅烧,成功制备出了具有大尺寸单晶颗粒状的高镍LiNi_0.8Co_0.1Mn_0.1O₂材料,并与传统固相反应煅烧制备的材料进行比对,通过XRD衍射分析其结构特征,反映阳离子混排程度。依托扫描电子显微镜和透射电子显微镜,表征其表面形貌和晶体特征,研究表明:在经过循环伏安测试后,在高倍率测试条件下,循环稳定性和容量保有量的优势明显,契合锂离子电池近些年在快速发展过程中所面临的安全稳定的条件。这种采用熔盐法制备的NCM-811材料为制备微米级单晶型的正极材料提供了新的思路。      

Redox behaviors and structural characteristics of Mn0.1Ce0.9Ox and Mn0.1Ce0.6Zr0.3Ox

Mn0.1Ce0.9Ox and Mn0.1Ce0.6Zr0.30x samples synthesized by sol-gel method were tested for redox properties through the dynamic oxygen storage measurement and characterized using X-ray diffraction, BET, electron paramagnetic resonance, and X-ray photoelectron spectroscopy. The results showed that redox performances of ceria-based materials could be enhanced by synergetic effects between Mn-O and Ce-O. Fresh and aged samples were characterized with the fluorite-type cubic structure similar to CeO2, and furthermore, the thermal stability of Mn0.1Ce0.9Ox materials was improved by the introduction of some Zr atoms. From XPS, it could be concluded that Mn^2＋/Mn^3＋ redox couples existed on the surface of Mn0.1Ce0.9Ox and Mn0.1Ce0.6Zr0.3Ox samples. Electron paramagnetic resonance researches revealed that there were three types of Mn^2＋ species： isolated Mn^2＋ substituting for Ce^4＋ ions in the lattice with a cubic symmetry, ones in defect with a noncubic symmetry, and at the surface of samples.     

Chemical synthesis and properties of La1.9Ba0.1MO1.9Mn0.1O9 as electrolyte for IT-SOFCs

The highly phase-pure electrolyte materials with compositionLa1.9Ba0.1MO1.9Mn0.1O9（LBMMO） was prepared by the sol-gel auto-combustion method for intermediate-temperature solid oxide fuel cells （IT-SOFCs）. The details ofgel＇s auto-combustion, phase evolution, sintering, thermal expansion and electrochemical performance of LBMMO were investigated by means of thermo-gravimetry （TG）, X-ray diffxaction （XRD）, scanning electron microscopy （SEM）, transmission electron spectroscopy （TEM）, thermal expansion curve （TEC） and complex impedance spectra. The results showed that the highly phase-pure electrolyte LBMMO could be obtained after calcining at 600 ℃. The sample sintered at 900 ℃ for 4 h in air exhibited a better sinterability, and the relative density of LBMMO was higher than 96%. The electrical conductivities of the sample were 6.7x 10-3 and 25.9× 10-3 S/cm at 700 and 800 ℃ in air, respectively. Results also showed that LBMMO had moderate thermal expansion （a=16.3×10-6 K-l, between room temperature and 800 ℃） and an electrical activation energy equal to 1.32 eV）.     

Airway occlusion pressure at 0.1 s (P0.1) after extubation: an early indicator of postextubation hypercapnic respiratory insufficiency

OBJECTIVE: To examine variables associated with postextubation respiratory distress in chronic obstructive pulmonary disease (COPD) patients. DESIGN: Prospective, clinical investigation. SETTING: Intensive care unit of a university hospital. PATIENTS: Forty COPD patients, considered ready for extubation. MEASUREMENTS AND MAIN RESULTS: We recorded, from the digital display of a standard ventilator, breathing frequency (f), tidal volume (VT) and f/VT for the respiratory pattern, airway occlusion pressure at 0.1 s (P0.1) for the respiratory drive and measured blood gases: i) before extubation, following 30 min of a 6 cm H2O pressure support (PS) ventilation trial, ii) 1 h after extubation, at the 30th min of a face mask 4 cm H2O PS ventilation trial. According to the weaning outcome, the patients were divided into two groups: respiratory distress, and non-respiratory distress within 72 h of the discontinuation of mechanical ventilation. The respiratory distress was defined as the combination of f more than 25 breaths/min, an increase in PaCO2 of at least 20% compared with the value measured after extubation, and pH lower than 7.35. We determined whether those patients who developed respiratory distress after extubation differed from those who did not. Respiratory pattern data and arterial blood gases recorded, either before or after extubation, and P0.1 recorded before extubation, were inadequate to differentiate the two groups. Only P0.1 recorded 1 h after the discontinuation of mechanical ventilation differentiated the patients who developed respiratory distress from those who did not (4.2+/-0.9 vs 1.8+/-0.8, p < 0.01). CONCLUSIONS: P0.1 recorded after extubation may be a good indicator of postextubation respiratory distress. Measuring P0.1 and/or the analysis of the evolution of this parameter could facilitate decisions during the period following extubation.     

Y2O3 modification on nickel-rich LiNi0.8Co0.1Mn0.1O2 with improved electrochemical performance in lithium-ion batteries

Doping and coating are frequently employed for the improvement of the properties of Ni-rich NCM materials.In this work,we prepared stable LiNi_0.8Co_0.1Mn_0.1O₂(NCM811)materials modified withY₂O₃via a wet chemical method.In order to investigate the action mechanism ofY₂O₃on NCM811,we analyzed the micro structures using X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).Also,to study the electrochemical performances,we conducted a charge/discharge test and cyclic voltammetry.Our results show thatY₂O₃modified NCM811 materials have good thermal stability,and proper content ofY₂O₃can effectively prevent the materials from damaging and significantly improve the electrochemical properties of the materials.Particularly,1%Y2 O3 modified NCM811 material show much better cycling performance than other samples.During cycling at 1.0 C the 1%Y2 O3 modified NCM811 shows capacity retention of 90.1%after 100 cycles,which is higher than 69.4%for pristine NMC811.We examined the microstructures of the materials before and after circulation.Using the SEM results,we conclude that structural changes are among the key factors that lead to the degradation of the electrochemical properties of materials.     

Study of humidifying oxygen with 0.1 copper sulfate solution

The 0.1/dL copper sulfate solution may be used to replace distilled water for humidifying oxygen. It can reduce the carrier rate and prolong the using time. There is little copper-ion in the oxygen while the 0.5/dL copper sulfate solution were used continuously for 9 days. The oxygen humidified by copper sulfate solution has no peculiar smell. The solution is cheap, easy to make, and has broad bacteriostatic spectrum.     

Cu-0.1%Ag 合金的晶粒显示和分析

The selection of etchant and the analysis of grain are the key to test method of grain of Cu Ag alloy. The results show that etchant composed of a mixture of 2g ferric nitrate and 50mL anhydrous ethanol is suitable for displaying the grains of Cu-0.1% Ag alloy.The grain boundary of metallographic structure is clear and the grains are complete. The microstructure of the alloy is mainly composed of single-phase Cu solid solution, and equiaxed grains, crystal twin, columnar grains and fibrous tissue appear, which is closely related to the properties of the alloy.