风电叶片复合材料在高温环境下的拉压力学性能研究

为了探究高温环境对风电叶片玻纤/环氧树脂复合材料拉压力学性能的影响，采用真空辅助RTM工艺制备叶片用单向玻纤/环氧树脂复合材料层合板，研究复合材料从常温到65℃高温下的拉伸、压缩力学性能，并利用扫描电子显微镜（SEM）对压缩试样断口的微观结构进行表征分析。结果显示：复合材料的纵向拉伸强度和压缩强度随温度升高均有不同程度的下降，纵向压缩强度在高温下的降幅更大，当环境温度高于50℃，纵向压缩强度将低于材料设计值；纵向拉伸模量和压缩模量随温度升高变化较小，横向拉伸强度和模量随温度升高均有明显下降。高温环境引起复合材料拉压力学性能下降主要是由于复合材料在高温下玻纤与树脂基体的界面黏结减弱以及树脂性能降低所致。     

陶瓷纤维增强铝基复合材料在发动机活塞上的应用

本报导了陶瓷纤维增强复合材料的性能、制备研究及其在内燃机活塞上的应用。氧化铝或硅酸铝短纤维增强铝基复合材料比基体材料有更优异的高温综合性能。挤压铸造工艺生产的局部增强铝基复合材料活塞，界面结合可靠、成品率高、工艺兼容性好，作为新型活塞材料，已在我国发动机行业应用并达到批量生产。     

复合材料输电线杆应力－应变关系研究

采用自制的复合材料动态变温拉伸实验装置,研究了玻璃布-环氧层板（GFRP）在0℃、-30℃低温环境下的冲击拉伸力学性能,获得了在0℃、-30℃时GFRP材料的动、静态拉伸力学性能参数。结果表明：在10％到1/s应变率范围和低温条件下GFRP材料具有明显的应变率效应和温度效应。在低温环境下,当应变速率提高时,拉伸强度明显增大;和室温情形相比,在低温环境下,GFRP材料的拉伸强度有所提高。实验还发现,在低温环境下GFRP材料具有动态韧性。     

高温叶片钢2Cr10MoVNbN的应用性能研究

为了实现高温叶片钢2Cr10MoVNbN的国产化应用,从叶片的高温、高应力、高转速等严苛工况条件的角度,通过试验研究2Cr10MoVNbN钢的高温瞬时拉伸性能、疲劳性能、高温持久性能和物理性能等应用性能,并介绍了各种应用性能的理论基础和钢的强化机理。试验结果显示:1)随温度升高2Cr10MoVNbN钢的强度逐渐降低,在低温阶段延伸率和断面收缩率缓慢下降,在中温阶段塑性最差,进入高温阶段后随温度升高塑性大幅升高;2)2Cr10MoVNbN钢在高温下仍保持高的疲劳强度,疲劳性能优良;3)2Cr10MoVNbN钢的高温持久性能优良,在高温、长时条件下仍保持高的强度。试验证明2Cr10MoVNbN钢是一种理想的超临界、超超临界汽轮机高温叶片材料。     

滑动轴承-铜合金——第一部分:整体和多层滑动轴承用铸造铜合金

1.适用范围 本部分规定了用于整体和多层轴承铸造铜合金的要求,作为选择通用铸造铜合金时参考。 2.参考标准 ISO/R400:铜和铜合金的拉伸试验。 ISO/ R401:铜和铜合金圆形管的拉伸试验。 ISO1338:铸造铜合金-成分和机械性能。 ISO4339:滑动轴承-整体铜合金轴套-尺寸与公差。 ISO4383:滑动轴承-薄壁滑动轴承用金属多层材料。 ISO4384:滑动轴承-轴承合金的硬度检验: 第一部分:复合材料 第二部分:整体材料     

KF-KCl/SiO_2复合材料的制备与储热性能表征

采用混合烧结工艺将相变材料KF-KCl和陶瓷材料Si O2进行复合,并添加聚乙烯醇作为黏结剂、B2O3作为烧结助剂,成功制备出一种陶瓷基复合结构储热材料。通过试验,确定了复合材料的烧结程序以及最佳的烧结温度。XRD分析表明,由KF-KCl/Si O2构成的复合结构储热材料各物质之间具有良好的化学相容性;TG-DSC分析表明,复合材料在591.7℃时出现吸热峰,相变潜热是157.4 J/g。该复合材料具有储热密度高、无需容器盛装等特点,可以实现高温储热。     

镍基合金C276高温拉伸力学性能的试验分析

在500～650℃高温条件下对镍基合金C276进行了拉伸力学试验.为了准确分析该材料的力学性能,采用真实应力、应变对试验数据进行了处理,分析了温度对弹性模量、屈服应力、断裂强度以及延伸率的影响,给出了该材料在真实应力、应变下各温度的应力-应变硬化系数,以及屈服强度和断裂应力随温度变化的关系曲线.结果表明:镍基合金C276在高温下具有屈服流变现象和良好的塑性.     

颗粒增强铸造铝合金内燃机活塞材料的研究

陶瓷颗粒增强铸造铝基复合材料，以其优异的性能和日益完善的成型工艺，在民用产品中具有广阔的应用前景。本文研究了ＳｉＣｐ颗粒增强ＺＬ１０８合金复合材料的熔剂法制备工艺和挤压铸造工艺，探讨了熔剂和挤压压力对颗粒复合度和均匀度的影响。结果表明，该材料具有卓越的机械性能和物理性能，是高负荷内燃机活塞的理想材料     

宽幅细晶TC4钛合金薄板的制备及其性能研究

研究了退火温度对成品板材组织、晶粒尺寸、室温力学性能的影响,并对板材进行了超塑拉伸试验研究。研究结果表明:在普通退火方式下,板材横纵向的抗拉强度和屈服强度随退火温度的升高而减小,延伸率呈现先增大后减小的趋势,在780℃时强度和塑性得到了良好的匹配;随退火温度的升高,初生α的晶粒尺寸略有增大。超塑拉伸试验结果表明:在温度为910℃,初始应变速率为4×10-4s-1,板材最大延伸率达到789%。     

颗粒增强铸造铝合金内燃机活塞材料的研究

陶瓷颗粒增强铸造铝基复合材料，以其优异的性能和日益完善的成型工艺，在民用产品中具有广阔的应用前景。本文研究了ＳｉＣｐ颗粒增强ＺＬ１０８合金复合材料的熔剂法制备工艺和挤压铸造工艺，探讨了熔剂和挤压压力对颗粒复合度和均匀度的影响。结果表明，该材料具有卓越的机械性能和物理性能，是高负荷内燃机活塞的理想材料。     

Evaluation of in-situ formed La2O3–TiO2–La2O2CO3 nanocomposite photocatalyst for H2 production

The photocatalytic evolution of H₂ over La₂O₃ decorated TiO₂ catalyst was examined under solar light. It was observed that during the course of the reaction, the transformation of La₂O₃/TiO₂ into La₂O₃–TiO₂–La₂O₂CO₃ occurred and these species effectively suppressed electron-hole pair recombination by forming electron trapping centres on the surface, resulting in an increased visible light absorption and improved H₂ yield. The 2 wt%La₂O₃/TiO₂ nanocomposite demonstrated better H₂ yield (～8.76 mmol (g_cat)^?1) than the bare TiO₂ (～1.1 mmol (g_cat)^?1). The catalyst was stable even after several consecutive recycles with no substantial loss of hydrogen production rate. The H₂ rates were correlated with the physicochemical characteristics of the catalysts examined by BET–SA, H₂-TPR, XRD, UV-DRS, Raman spectroscopy, FTIR, HRTEM, EPR and PL spectroscopy.     

Photocatalytic H2 production over RuO2@ZnS and RuO2@CuS nanostructures

Photocatalytic hydrogen production is a promising approach of sustainable economy, because a use of sunlight and water to produce a fuel will solve a problem of fossil fuels depletion. Metal sulfides are well known photocatalysts in water splitting process, but in absence of sacrificial electron donor they undergo a photocorrosion. In this paper we studied a possible strategy to protect the sulfide photocatalysts and to improve its photostability by a deposition of small amount of ruthenium oxide at surface of sulfides. Nanocrystalline zinc sulfide and copper sulfide were prepared in a hydrothermal way and have been functionalized by RuO₂. As prepared photocatalysts showed good activity towards hydrogen formation. Modification of sulfides with ruthenium oxide had a few positive effects: it expanded a light absorption range by photocatalysts, enhanced the photocatalytic activity towards H₂ formation, improved a photostability in comparison with neat ZnS and CuS as well as protected from the electronic and structural changes within semiconductors due to irradiation.     

Numerical study of the O2/CO2, O2/CO2/N2, and O2/N2-syngas MILD combustion: Effects of oxidant temperature,O2 mole fraction,and fuel blends

Moderate or Intense Low-oxygen Dilution (MILD) combustion of a syngas fuel under air-fuel, oxygen-enhanced, and oxy-fuel condition are numerically studied with using counterflow diffusion flame. Fuel composition, temperature of oxidant (T_ox), and oxygen mole fraction (X_O2) are selected as the main parameters. Fake species (FCO₂) with the same CO₂ physical properties is used for separation the physical and chemical effects of replacing CO₂ with N₂. According to the results, under the high preheating temperatures, the chemical effect of changing the oxidant composition from N₂ to CO₂ is the main reason of the changes in flame structure, ignition delay time (IDT) and heat release rate (HRR) while physical differences play a more prominent role in the low preheating temperature MILD combustion. In all X_O2, the physical and chemical effects of replacing CO₂ with N₂ have almost the same role on the maximum flame temperature. The results of IDT expressed that chemical discrepancies of CO₂ and N₂ play a key role on IDT enhancement by increasing CO₂ in the oxidant composition. The sensitivity analysis of CH₂O for variations of T_ox and X_O2 shows that reactions R54, R56, R58, and R101 are the main responsible of lower HRR and higher IDT by moving from air-syngas to oxy-fuel MILD combustion.     

Photocatalytic reduction of CO2 using TiO2 powders in supercritical fluid CO2

The photocatalytic reduction of CO₂ was investigated using TiO₂ powders in supercritical fluid CO₂. These were irradiated in a stainless steel vessel at 9.0 MPa and 35°C. After reducing the CO₂ pressure to the ordinary state, pure water was added to the vessel while avoiding air contamination. No gaseous reduction products were observed. Formic acid was obtained only in aqueous solution. The optimal irradiation time for the production of formic acid was 5 h. Addition of acidic solutions rather than pure water was preferable for formic acid formation. Formic acid seems to be produced through the protonation of reaction intermediates on TiO₂ powders in solutions. The CO₂-reduction system described here may be of practical value for efficient CO₂-conversion and fixation, storage of solar energy, and production of raw materials for the photochemical industry.     

保护气氛烧结炉

介绍了HIC封装管壳中玻璃绝缘子网带烧结炉的特殊机械结构、氮氢保护气氛系统和电气保护措施。确立了网带炉低速爬行力学模型及炉内合理的气氛流向。     

New gas chromatographic packing ZIF-67@NH2–SiO2 for separation of hydrogen isotope H2/D2

ZIF-67@NH₂–SiO₂ composites were prepared by loading the metal-organic frameworks ZIF-67 on amino modified SiO₂ gel particles (NH₂–SiO₂, 80–100 mesh) through layer-by-layer self-assembly method. Systematic investigation on the effects of ZIF-67 loading amounts on NH₂–SiO₂ packed stainless steel chromatographic column (specification 1.0 m×2.0 mm I.D.), the flow rate of He as carrier gas and the injection amount of mixed gas (H₂/D₂) on the hydrogen isotope H₂/D₂ separation performance at liquid nitrogen temperature, unraveled the optimal conditions for H₂/D₂ isotope separation. The results showed that the optimal stationary phase materials under the optimized conditions can effectively separate H₂ and D₂ with separation resolution R = 1.52 and the separation time t = 10.15 min. The superior performance of the ZIF-67 is tentatively thought to be due to kinetic quantum sieving (pore size 3.3 Å) effect and chemical affinity sieving effect of Co ion in ZIF-67.