共查询到20条相似文献，搜索用时 31 毫秒
1.
以吐温80为分散剂,分别以丙烯酰胺和N,N’-亚甲基双丙烯酰胺为单体和交联剂,制备中间相碳微球/石墨（MCMB/G）浆料,采用凝胶注模工艺,制得直接醇类燃料电池管状阴极支撑体素坯,经液态干燥、滚动干燥和埋石墨粉烧结等过程处理制得其样品。所制备的直接醇类燃料电池管状阴极支撑体物理性能为：孔隙率42.7%,电阻率0.0276Ω·cm,抗折强度6.23 MPa,抗压强度16.29 MPa,具有收缩率低、变形量小、石墨化度高、电导率高、力学性能好等特点。 相似文献
2.
3.
采用MP-PIC (multi-phase particle in cell)方法模拟了三维多段气化炉（上部快速床,下部鼓泡床）多粒径煤粉的循环流化过程,研究了分布板不同进气方向对气化炉内颗粒分布的影响。结果表明:分布板开孔与水平方向夹角越大,物料进入快速床并形成流化状态越快,但对成形后的流化形态影响较小;分布板进气方向对分布板处的轴向颗粒浓度分布影响较大,对快速床内轴向颗粒浓度分布影响较小;随着分布板进气方向与水平夹角的减小,鼓泡床下部颗粒浓度增大,固相颗粒通量增大;分布板进气方向对旋风分离效率影响较小。因此,工程上可根据需要适当减小分布板进气方向与水平方向的夹角来增加分布板上部颗粒浓度分布。 相似文献
4.
A cold-model vertical multi-tube circulating fluidized bed evaporator was designed and built to conduct a visualization study on the pressure drop of a liquid-solid two-phase flow and the corresponding particle distribution.Water and polyformaldehyde particle (POM) were used as the liquid and solid phases,respectively.The effects of operating parameters such as the amount of added particles,circulating flow rate,and particle size were systematically investigated.The results showed that the addition of the particles increased the pressure drop in the vertical tube bundle.The maximum pressure drop ratios were18.65%,21.15%,18.00%,and 21.15%within the experimental range of the amount of added particles for POM1,POM2,POM3,and POM4,respectively.The pressure drop ratio basically decreased with the increase in the circulating flow rate but fluctuated with the increase in the amount of added particles and particle size.The difference in pressure drop ratio decreased with the increase in the circulating flow rate.As the amount of added particles increased,the difference in pressure drop ratio fluctuated at low circulating flow rate but basically decreased at high circulating flow rate.The pressure drop in the vertical tube bundle accounted for about 70%of the overall pressure drop in the up-flow heating chamber and was the main component of the overall pressure within the experimental range.Three-dimensional phase diagrams were established to display the variation ranges of the pressure drop and pressure drop ratio in the vertical tube bundle corresponding to the operating parameters.The research results can provide some reference for the application of the fluidized bed heat transfer technology in the industry. 相似文献
5.
论述了在常温下和在大气状态下,扫描隧道显微镜（STM）在石墨薄膜表面上的电场加工实验,并对作用机理进行了分析,认为表面结构现象生成是场蒸发效应作用的结果,其导电性受外电场力的大小和薄膜层数之间的束缚力的影响。 相似文献
6.
7.
毛文宫 《福建工程学院学报》2022,(6):527-531
基于机械力化学作用原理,采用高速球磨法提高花岗岩石粉的胶凝活性。研究活化石粉掺量对胶砂抗压强度、折压比和干燥收缩性能的影响规律,结合XRD、SEM、MIP 等微观试验,揭示活化石粉的作用机理。试验结果表明:花岗岩石粉活性指数可从0.55 提升至0.73,活化石粉替代20%~30%水泥用量的胶砂强度28 d 抗压强度达30 MPa 左右,折压比提高约30%,干燥收缩降低约60%。 相似文献
8.
刘昱 《武汉工程职业技术学院学报》2014,(4):25-29
采用了E-44环氧树脂与柔性固化剂邻苯二甲酸酐和粉末石墨混合且加热模压同时进行的成型工艺制备出复合材料双极板。该方法采用流体环氧树脂且加热模压同时进行一次性完成复合材料双极板的成形。本研究利用万能材料测试机采用三点弯曲法对不同混合比例样品做了力学性能分析;热重实验验证了该样品在工作条件下的稳定性;SEM扫描电镜分析观察了其微观组织情况。结果表明本文工艺方案所制备样品性能要优于采用聚酰胺固化剂制备所得样品。 相似文献
9.
为了测定耐碱玻璃纤维混凝土的抗折强度并分析其不确定度及纤维体积率对混凝土抗折强度的影响,选择耐碱玻璃纤维体积率为0%0,.6%,0.8%,1.0%的100 mm×100 mm×400 mm混凝土抗折试件进行试验。试验在MTS810材料试验机上进行,通过三分点加载测定其抗折强度,分析混凝土抗折强度试验中影响试验结果不确定的因素和来源,并按照JJF 1059-1999标准的要求,对合理玻璃纤维掺量试件的抗折强度的不确定度进行分析和评定。结果表明:耐碱玻璃纤维的掺入改变了混凝土抗折破坏形式,不同纤维体积率的混凝土抗折强度较普通混凝土依次提高了18.87%,21.64%,23.24%。综合考虑各方面因素确定耐碱玻璃纤维混凝土合理玻璃纤维掺量为0.6%;通过对试件抗折强度测定的不确定度评定,表明数学模型中自由度及测量的重复性是引入测量结果不确定度的主要因素;建议在进行同类试验时,试件尺寸应尽量大,从而可增大跨距,以减小剪力对测量结果的影响。 相似文献
10.
郑珂 《陕西教育学院学报》2009,25(4):79-83
利用薄板的弯曲振动理论推导出了不同边界条件下,改进弯振圆板在不同振动模式下的波节圆半径。利用瑞丽积分求解出了具有一个环带辐射区的弯振板的通用声压及指向性表达式,编制程序并绘出了弯振板轴对称弯曲振动时辐射声压的远场指向性图,同时对不同边界的声场指向性图作了对比。结果表明自由边界的改进弯振圆板辐射声场指向性最强。本文为此类弯振板的理论设计及实际应用提供了一定的理论依据。 相似文献
11.
Our research focused on the analysis of concrete deterioration mechanism under the coupling effects of flexural load, cyclic wetting and drying, and sulfate. The relative dynamic modulus of elasticity of a corroded concrete sample was tested, and scanning electron microscope was used to observe the microstructure of concrete under the coupling effects of flexural load, cyclic wetting and drying, and sulfate. Results manifested that flexural load and cyclic wetting and drying during the concrete service changed the corrosion process of the sulfate medium in concrete and enhanced the deterioration of concrete performance. Furthermore, the influencing patterns of strength grade of concrete, mass concentration of sulfate solution, and mineral admixtures on the degree of concrete deterioration were identified. 相似文献
12.
对薄圆盘的弯曲振动和辐射声场的特性进行了研究,推导出了三种边界条件下圆盘辐射声场指向性的数值表达式,编制程序并研究其声辐射特性。结果表明,相同尺寸不同边界条件下圆盘指向性的尖锐程度不同,固定边界条件下圆盘辐射声场指向性最佳,自由边界条件下较差,并且随着圆盘模式和几何尺寸的增加各边界条件下圆盘的指向性均逐渐变差。 相似文献
13.
This paper studies the effect of sample size on the stress-strain behavior and strength characteristics of geotextile reinforced sand using the finite element numerical analysis. The effect of sample size was investigated by studying the effects of varying the number of geotextile layers, the confining pressure and the type of geotextile. Modeling was performed on samples with five different diameters： 38, 100, 200, 500 and 600 mm. The elastic-plastic Mohr-Coulomb model was used to simulate sand behavior. Results showed that small-sized samples show higher values of peak strength and higher axial strain at failure in comparison with large-sized samples. The size effect on the behavior of samples became further apparent when the number of geotextile layers was increased or the confining pressure was decreased. In addition, the results indicated that the magnitude of the size effect on the mechanical behavior of reinforced sand decreases with an increase in the sample size. 相似文献
14.
Li Y Luo ZY Yu CJ Luo D Xu ZA Cen KF 《Journal of Zhejiang University. Science. B》2005,6(11):1124-1129
INTRODUCTION The solid oxide fuel cell (SOFC) has attracted much attention as a promising source of electrical power generation because of its high efficiency in converting chemical energy to electrical power. De- velopment of SOFC with operating temperature of less than 800 °C has been extensively studied. SOFC has the potential to have the cost of its materials, cell fabrication, and corrosion of its stack components dramatically reduced. Gadolinia-doped ceria with the chemical fo… 相似文献
15.
以超细钢铁渣粉(以下简称“超细钢渣”) 为主要掺合料制备胶凝材料,通过XRF、粒径分析、XRD分析和力学性能测试,探究超细钢渣对水泥基材料的力学性能影响。结果表明:通过机械研磨制备出的超细钢渣,其矿相成分硅酸三钙、硅酸二钙和莫来石特征峰强度最强,复掺的超细钢渣活性指数也满足国家标准。随着超细钢渣掺量增加,3 d 抗压和抗折强度均出现逐渐降低的趋势,但在外掺m (超细钢渣) ∶ m (超细矿渣)= 2:3、w复合粉=30%时,其28 d 抗压和抗折强度达到峰值,分别为8.9、53.8 MPa。超细钢渣在不同龄期水化反应程度不同,早期水化反应较低,强度较差;后期水化程度较高,且优于同标准水泥。 相似文献
16.
INTRODUCTION A number of experimental fatigue studies were conducted on plain concrete as well as on steel fibre reinforced concrete (SFRC) beams of different sizes under different loading conditions. Murdock and Kesler (1958) investigated the effect of stress ratio on the fatigue strength of plain concrete. Batson et al.(1972) reported fatigue strength of 74% and 83% of the first crack static flexural strength at 2 million cycles of complete reversed and not-reversed loads respectively… 相似文献
17.
Amorphous SiBCNAl powders were prepared via a mechanical alloying (MA) technique using crystalline silicon (Si), hexagonal boron nitride (h-BN), graphite (C), and aluminum (Al) as starting materials. SiBCNAl powders were consolidated by a hot pressing (HP) technique at 1800 °C under a pressure of 30 MPa in argon and nitrogen. The sintering atmosphere had a great influence on the microstructures and mechanical properties of the ceramics. The two ceramics had different phase compositions and fracture surface morphologies. For the ceramics sintered in argon, flexural strength, fracture toughness, elastic modulus and Vickers hardness were 421.90 MPa, 3.40 MPa·m1/2, 174.10 GPa, and 12.74 GPa, respectively. For the ceramics sintered in nitrogen, the mechanical properties increased, except for the Vickers hardness, and the values of the above properties were 526.80 MPa, 5.25 MPa·m1/2, 222.10 GPa, and 11.63 GPa, respectively. 相似文献
18.
19.
侯东彪 《邢台职业技术学院学报》2014,(3):92-95
本文指出了中子应用的安全性问题,介绍了中子防护的特点和防护材料的选择。分析了煤质分析仪的外部辐射特征,确定了设备外部中子及γ射线的强弱分布。通过研究中子的慢化吸收过程确定中子防护材料,并对γ射线吸收材料的厚度进行了研究,检验了防护效果。采用MCNP程序对不同防护材料厚度做了定量的模拟研究,确定了可达到相关国家标准的相应尺寸。结果显示采用聚乙烯水箱和加硼石墨板可有效吸收中子辐射;Pb板对γ射线的屏蔽效果很好。通过模拟方法比较了防护层排布顺序和不同能量中子源对防护效果的影响。 相似文献
20.
应用有限元方法,计算分析不同数量及不同的接头角板位置对相互垂直的不等宽空间三杆结构的承载性能影响,结果表明,角板平面与载荷力平行时,能有效提高结构的刚度和强度;与载荷力垂直方向时,对结构刚度与强度影响很小;接头角板位置不同,对结构刚度占强度影响也是不同. 相似文献