MoO_3掺杂对高纯Zr_（0.84）Y_（0.16）O_（1.92）体系结构和电性能的影响

采用溶胶-凝胶法合成高纯（SiO2〈50 mg/kg）Zr0.84Y0.16O1.92＋x MoO3（0.00≤x≤0.07）固溶体,研究MoO3的掺杂量对Zr0.84Y0.16 O1.92体系结构和电性能的影响。通过X射线衍射（XRD）和场发射扫描电子显微镜（FE-SEM）对材料进行表征,交流阻抗谱（AC）测试材料的电性能。结果表明,掺入MoO3后,体系仍保持立方莹石型结构;MoO3掺杂于Zr0.84Y0.16O1.92固体电解质的最佳掺量为0.05%;MoO3具有降低体系烧结温度、促进晶粒生长和提高体系致密度的作用,掺入MoO3的Zr0.84Y0.16O1.92体系晶界电导率和总电导率提高。     

MoO3掺杂对高纯Zr0.84Y0.16O1.92体系结构和电性能的影响

采用溶胶-凝胶法合成高纯(SiO2<50 mg/kg)Zr0.84Y0.16O1.92+x MoO3(0.00≤x≤0.07)固溶体,研究MoO3的掺杂量对Zr0.84Y0.16 O1.92体系结构和电性能的影响。通过X射线衍射(XRD)和场发射扫描电子显微镜(FE-SEM)对材料进行表征,交流阻抗谱(AC)测试材料的电性能。结果表明,掺入MoO3后,体系仍保持立方莹石型结构;MoO3掺杂于Zr0.84Y0.16O1.92固体电解质的最佳掺量为0.05%;MoO3具有降低体系烧结温度、促进晶粒生长和提高体系致密度的作用,掺入MoO3的Zr0.84Y0.16O1.92体系晶界电导率和总电导率提高。     

YBaCo_2O_(5+δ)阴极材料的微观结构和热膨胀及电性能(英文)

研究了层状钙钛矿钴氧化物YBaCo2O5+δ阴极材料的微观结构和热膨胀及电性能.结果表明:YBaCo2O5+δ极材料具有与Ce0.8Gd0.2O2-δ固体电解质相匹配的热膨胀性能,显示出良好的化学和结构稳定性.YBaCo2O5+δ在高温下表现为金属导电特性,100~800℃温度范围内的电导率σ=153~35 S/cm.通过扫描电子显微镜和电子能谱手段,研究了YBaCo2O5+δ/Ce0.8Gd0.2O2-δ复合阴极中离子-电子混合导电相的微观结构.     

新型陶瓷连接材料(Pr0.5Nd0.5)0.7Ca0.3CrO3–δ–Sm0.1Gd0.1Ce0.8O1.9的制备与性能

采用络合燃烧法制备(Pr0.5Nd0.5)0.7Ca0.3CrO3–δ(PNCC)–Sm0.1Gd0.1Ce0.8O2–δ(SGDC)复合陶瓷连接材料。利用X射线衍射仪和扫描电子显微镜对烧结体的物相和微观结构进行了表征,采用四端探针法测量电导率。结果表明:PNCC和SGDC在高温烧结时具有稳定的物相和良好的化学相容性,SGDC掺杂量为5%(质量分数)的样品,在1400℃烧结5h,相对密度高达97.1%;700℃时,烧结陶瓷体在空气和氢气气氛中的电导率分别为47S/cm和4S/cm;室温至1000℃范围内,样品的热膨胀系数为10.4×10–6K–1,与中温电解质的热膨胀系数接近,说明SGDC掺杂的PNCC体系有望成为良好的中温固体氧化物燃料电池复合连接材料。     

Ce掺杂Na_(0.25)K_(0.25)Bi_(2.5)Nb_2O_9-0.4wt%Cr_2O_3高温无铅压电陶瓷的研究

采用固相法制备了Na0.25K0.25Bi2.5Nb2O9-0.4wt%Cr2O3-xwt%CeO2(x=0.00~1.00)高温无铅压电陶瓷,研究了Ce掺杂对该系列陶瓷微观结构及电性能的影响。结果表明所有样品均为单一的铋层状结构陶瓷,适量的Ce掺杂明显改善了陶瓷的压电与铁电性能,降低了陶瓷的电导率和介电损耗。当掺杂量x=0.50时,样品具有最佳性能:d33=27 pC/N,tanδ=0.09%,kp=7.97%,Qm=2637,Tc=656℃,Ec=46 kV/cm和Pr=4.4μC/cm2,表明该材料在高温领域内具有良好的应用前景。     

溶胶凝胶法制备Ce_(0.8)Y_(0.2-x)Ca_xO_(2-δ)电解质材料及其性能

采用溶胶-凝胶法制备出Ce0.8Y0.2-x Cax O2-δ(0.02≤x≤0.10)系列电解质材料。通过红外、热重、X射线衍射、扫描电子显微镜、透射电子显微镜、交流阻抗和热膨胀系数测试对试样进行分析。结果表明:采用溶胶-凝胶法经600℃煅烧所得粉体形成了单相立方萤石结构,平均晶粒尺寸在5~10nm之间;Ce0.8Y0.2-x Cax O2-δ超细粉体具有较高的烧结活性,在1 400℃烧结得到的Ce0.8Y0.2-x Cax O2-δ系列电解质陶瓷的相对密度均大于96%。在该系列材料中,Ce0.8Y0.1Ca0.1O1.85具有良好的离子导电率、较低的电导活化能和适中的热膨胀性能。它在800℃时的离子电导率为0.041S/cm,电导活化能为0.81eV,热膨胀系数为13.5×10-6 K-1(常温~800℃)。     

Preparation and Performance of Novel Ceramic Interconnect Materials （Pr0.5Nd0.5）0.7Cao.aCrO3-δ-Sm0.1Gd0.1Ce0.8O1.9

采用络合燃烧法制备（Pro5Ndo5）07Ca0.3CrO3-δ（PNCC）-Sm0.1 Gd 0.1Ce0.8O2-δ（SGDC）复合陶瓷连接材料。利用X射线衍射仪和扫描电子显微镜对烧结体的物相和微观结构进行了表征,采用四端探针法测量电导率。结果表明：PNCC和SGDC在高温烧结时具有稳定的物相和良好的化学相容性,SGDC掺杂量为5％（质量分数）的样品,在1400℃烧结5h,相对密度高达97．1％;700℃时,烧结陶瓷体在空气和氢气气氛中的电导率分别为47S／cm和4S／cm;室温至1000℃范围内,样品的热膨胀系数为10．4×10^-6 K^-1,与中温电解质的热膨胀系数接近,说明SGDC掺杂的PNCC体系有望成为良好的中温固体氧化物燃料电池复合连接材料。     

钨离子掺杂对Ca0.7La0.3Bi4(Ti1-xWx)4O15陶瓷性能的影响

用固相法研究了钨离子(W6 )掺杂对铋层状钛酸铋钙镧[Ca0.7La0.3Bi4(Ti1-xWx)4O15,CLBTWx]陶瓷的铁电性能、介电性能和压电性能的影响,得到了W6 掺量与铋层状CLBTWx陶瓷性能的关系.用X射线衍射和扫描电镜研究了W6 掺量对铋层状CLBTWx陶瓷微观结构和物相的影响,探讨了W6 掺杂改性的机理.结果表明:随着W6 掺量的增加,CLBTWx陶瓷的介电常数(ε)先增大后减小;介质损耗(tanδ)先减小后增大;压电应变常数(d33)先增大后减小;剩余极化强度(Pr)先增大后减小然后再增大再减小;矫顽场(Ec)变化规律与Pr的相同.当W6 掺量为0.025mol时,可得到综合性能好的无铅铋层状CLBTWx陶瓷,其烧结温度为1 120～1 140℃时,CLBTWx陶瓷的ε=183.15;tanδ=0.00446;d33=14×10-12C/N;2Pr=26.7μC/cm2;2Ec=220kV/cm.该类材料适合于制备铁电随机存取存储器和高温高频压电器件.W6 掺杂从生成钙空位或铋空位、形成焦绿石相、促进陶瓷致密化、偏析晶界影响陶瓷晶粒的均匀生长等方面来影响铋层状CLBTWx陶瓷性能和结构.     

固溶体Ce1-xEuxO2-δ的导电性能

利用溶胶-凝胶法,经800℃焙烧10h合成了Ce1-xEuxO2-δ(x=0.05～0.50)固溶体.用X射线衍射仪检测了样品的结构,测量了样品的阻抗谱和电子顺磁共振谱.结果表明:当掺杂量x≤0.40时,固溶体的结构为单相立方萤石结构,晶胞参数随x的增加而增大.样品中存在Ce3 ,掺杂Eu3 可以抑制Ce4 离子的还原.通过掺杂使固溶体Ce1-xEuxO2-δ(x=0.10～0.40)的电导率提高,随着掺杂量x增加,电导率增大,并在x=0.20时达到最大值(500℃的电导率σ500℃=1.07×103S/cm);电导活化能减小,x=0.20时,电导活化能Ea达到最小值,为0.72eV.     

中温固体氧化物燃料电池Gd1-xSrxCoO3-δ系阴极材料的制备及性能测试

采用甘氨酸-硝酸盐法(the glycine-niwate process,GNP)合成了新型中温固体氧化物燃料电池(intermediate temperature solid oxide fuel cell,IT-SOFC)阴极材料Gd1-xSrxCoO3-δ(x=0～0.5),所合成的初始粉体在800℃下煅烧12h后均形成了钙钛矿结构的单相固溶体.对该体系材料的电导率、界面阻抗进行了系统的研究后发现,Gd0.8Sr0.2CoO3-δ的电导率在600℃时达到了559 S/cm,CJd0.8Sr0.2CoO3-δ与Ce0.8Gd0.2O1.9(GDC)在600℃和700℃ 的界面阻抗分别为0.34 Ω·cm2和0.11 Ω·cm2,活化能为仪98.4 kJ/mol,预示其可以作为IT-SOFC较为理想的阴极备选材料.此外,通过调整Gd0.8Sr0.2CoO3-δ与GDC的比例可以制备出热膨胀系数与GDC电解质匹配、性能良好的Gd0.8Sr0.2CoO3-δ、GDC复合阴极材料.     

Ultrafast high-temperature sintering of Li7La3Zr1.75Nb0.25Al0.15O12 (LLZO)

Rapid sintering of Li₇La₃Zr_1.75Nb_0.25Al_0.15O₁₂ (LLZO) is reported. The selection of heating elements, the effect of powder preparation and MgO additions in rapid sintered LLZO are described. Annealing LLZO powder at 750 ºC for 2 h in argon immediately before pressing helped to minimize porosity. A 15–20 s hold at 1372 ºC was sufficient to achieve densities >97%. The total sintering schedule time for rapid sintering represents a 99.7% decrease in sintering time compared to conventional sintering. At 70 °C under a pressure of 4.12 MPa cells had a critical current density of 1020 µA/cm².     

Influence of an Electric Field on the Burning Behavior of Solid Fuels and Propellants

An experimental study on the effects of an applied external electric field on the combustion behavior of solid fuels and solid propellants has been conducted. In an opposed flow burning configuration, application of an electric field was shown to extinguish a paraffin fuel and gaseous oxygen flame over a broad range of operating conditions. When subjected to the electric field, burning paraffin fuel strands were found to extinguish at various axial locations relative to the exit of the oxidizer gas jet. Extinguishment location was found to be a function of field strength as well as electrode surface area, while changes in polarity did not significantly alter the results. In addition, the combustion behaviors of two composite solid rocket propellants were studied while subjected to an external electric field. Both propellants were based on HTPB/AP combinations, with one propellant containing aluminum and the other being non‐aluminized. Application of an electric field to the composite solid rocket propellant strands demonstrated decreases in propellant burning rate under all operating conditions for both propellants including changes in polarity. The flame structure of the aluminized propellant was examined closely as the luminosity, flame length, and flame width varied significantly with field strength and burning location of the strand relative to the electrodes.     

齿轮油泵参数化设计系统

通过对参数化所涉及的关键技术进行理论分析,构建了齿轮油泵参数化系统总体方案;提出产品参数化模型;对总装配体驱动尺寸与参数化系统驱动尺寸的对应关系进行分析;结合Solid Works和VB软件,以某型号齿轮油泵为基型,编制系统控制程序,开发出具体的齿轮油泵参数化设计系统,工程实用性强.     

Solid Edge在化工装备中管道设计的使用

Solid Edge是非常优秀的三维建模软件，它以卓越的性能。优异的造型功能，众口皆碑的易用性和专业化的设计环境赢得了业界广泛的赞誉。尤其Solid Edge与部分三维软件之间的无缝接口，使它在产品设计占有重大的地位。本文针对Solid Edge在管道设计功能．对其用户界面、常用命令作一分析研究。     

Characteristics of solid hold up and circulation rate in the CFB reactor with 3-loops

The effects of the U_o, PA/[PA+SA] ratio, total solid inventory and fluidizing velocity of loopseal on the axial solid holdup and the solid circulation rate have been determined with different particle sizes (174, 199, 281, 377 μm) and particle types (silica sand: narrow PSD, coal ash: wide PSD) in a CFB reactor with 3-loops. A simple model for solid hold-up based on the previous works was in agreement with the experimental data. With increasing U_o, G_s increased exponentially, and in the center-loop, G_s was 1.5 times larger than that found in the other side-loops. As the PA/[PA+SA] ratio increased, and as SA injection port was placed at a lower part in the riser, the axial solid holdup and G_s increased. With increasing fluidizing velocity of loopseal to about 1.5u_mf, G_s somewhat increased, but above the gas velocity of 1.5u_mf, the loopseal lost the ability of the control ofGs. The following correlation for the solid circulation rate in the CFB was developed with good accuracy; G, = ϕ,[PA/TA]²⁺[H _l /H _l ]^0.5[Ar]^-188[Fr]^2k+[KU₁/U _l ]^3-45     

Hydrodynamic characteristics of fine particles in the riser and standpipe of a circulating fluidized bed

The hydrodynamic properties in the riser and standpipe. and the cyclone efficiency have been determined in a circulating fluidized bed (CFB) unit consisting of a riser (0.05 m-IDX3.8 m high), a standpipe (0.068 m-IDX2.5 m high) as a primary cyclone/bubbling fluidized bed, and a secondary cyclone. Silica gel powder (mean diameter = 46 μm) was used as the bed material. The effects of gas velocity in the riser and initial solid loading on the solid circulation rate, and the solid holdups in the riser and standpipe have been determined. The effects of gas velocity in the standpipe on the efficiencies of primary and secondary cyclones have been also determined as functions of solid circulation rate and solid entrainment rate. The solid circulation rate increases with increases in the gas velocity in the riser and in the initial solid loading. The efficiencies of primary and secondary cyclones increase with an increase in the gas velocity in the riser. However, the efficiency of primary cyclone decreases and that of secondary cyclone increases slightly, with an increase in the gas velocity in the standpipe.     

Synthesis,sintering and characterization of ceria-based solid electrolytes codoped with samaria and gadolinium using the Pechini method

Studies on fuel cell components have attracted interest due to the growing demand for sustainable energy sources. In the present study, synthesis of nanometric powders of the Ce_0.8Sm_0.2−xGd_xO_1.9 system (x = 0; 0.05; 0.1) system was carried out using the polymeric precursor method (Pechini), followed by calcination at 600 °C for 1 h and pressureless sintering. Characterizations were carried out with differential thermal analysis (DTA), thermogravimetric analysis (TG), infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The grain and grain boundary contributions to the ionic conductivity of the ceramic disks obtained were assessed by complex impedance spectroscopy (CIS). Microstructural characterization was conducted by SEM. Electrical characterization showed greater grain conductivity for samples that were codoped with increasing levels of gadolinium, likely due to less deformation in the crystalline lattice with the addition of an element that contains an ionic radius closer to that of the host matrix of ceria (Ce < Gd < Sm). Grain boundary conductivity was lower than grain conductivity with a gradual rise in the same codoping element. This results from changes in microstructural characteristics due to increased codoping, including a reduction in relative density.     

固体醇燃料的制备

用硝化纤维素作凝胶剂合成了固体醇燃料,并研究了各组分的作用及影响。与传统固体醇燃料相比,用硝化纤维素作凝胶剂制成的固体醇燃料具有价廉易得、燃烧热值高、燃后残渣少、不产生黑烟、不需要加热或改性处理等优点。     

Fundamental study on the preparation of insulating ceramics via the phase reconstruction of phosphate tailings

Insulating ceramics with anorthite and diopside as the main crystal phases were manufactured using phosphate tailings, coal gangue, and quartz as raw materials, which were fired at 1160–1190 °C for 2 h. The structure and micromorphology of the samples were investigated using X-ray diffraction, field-emission scanning electron microscopy, and X-ray photoelectron spectroscopy. Dense ceramic samples exhibited an apparent porosity of less than 0.3%, densities of 2.64–2.86 g/cm³, bending strength of 127.71–172.73 MPa, dielectric constants of 6.98–7.79, and dielectric losses of 0.0086–0.0024 at 20 °C and frequency of 1 MHz. The effects of impurity elements on ceramic properties are determined. The excellent electrical properties can be attributed to the solid solution of iron in the crystalline phases, such as diopside, which reduce leakage conductance in ceramics and alleviate the influence of relaxation and space charge polarization on the electrical properties of ceramics. This study provides a new strategy for preparing high-value insulating ceramics from solid waste.     

新型催化剂上醇醛缩合的进展

综述了近几年来在醇醛缩合反应中,各种固体催化剂的研究进展,其中有固体酸碱催化剂及新型的固体手性催化剂,评论了各自的反应活性及影响因素。