关于钢筋混凝土蓄冰池保温厚度的测算

本文分三种情况测算了在冰蓄冷空调系统中经常用到的钢筋混凝土蓄冰池保温层的厚度,根据工程的设计施工经验,提出了合理的蓄冰池结构及置放方式,可以减少蓄冰池热量损失,达到节能、节省空间和节省费用的目的。     

微波法制备γ-Al2O3蜂窝陶瓷涂层的实验研究

采用微波加热法制得了γ-Al₂O₃蜂窝陶瓷涂层及相应的三效催化剂.比较并详细分析了微波涂层（TC-B）与传统涂层（TC-A）在晶型、比表面积及三效催化剂活性上的差别.结论是.微波涂层的主要特性参数均达到或超过了传统涂层.以微波法制备γ-Al₂O₃涂层的工艺过程能耗少、周期短、生产成本低.     

In situ study of the scale formation on γ-TiAl during isothermal oxidation at 700°C and on heating

Abstract

Time and temperature resolved X-ray diffraction as an in situ method and electron microprobe analysis for post oxidation studies were used for the investigation of the oxide scale formation on γ-TiAl at 700°C and during stepwise heating from room temperature to 950°C in air and in He with 19 vol% O₂.

The formation of alumina in the form of α-Al₂O₃ and of TiO₂ in the form of rutile was observed in both atmospheres and additionally, TiN was found during oxidation in air. Furthermore, diffraction peaks of two phases were detected, which do not exist in the data base for X-ray diffraction JCPDS-ICDD, and are different in air (X′- and X-phase) and in He with 19vol% O₂ (Z-phase).

In air, TiO₂ grows faster than the α-Al₂O₃ and the growth of TiO₂ is not parabolic in the first 50 hours. An oxide scale of 5 μm thickness consisting of a mixture of α-Al₂O₃ and TiO₂ is observed. In He with 19vol% O₂ the formation of TiO₂ is slower than of α-Al₂O₃ resulting in a thinner oxide scale.     

Study of microstructure degradation and rejuvenation evolution for F-class gas turbine blade

Service degradation of F-class gas turbine blade and its microstructure evolution during a simple rejuvenation process are investigated, and then microhardness of the rejuvenated blade is evaluated. The results show that the turbine blade suffers from significant service degradation such as spheroidising, coarsening and rafting of the γ′ phase. It is also verified that the γ′ precipitates microstructure could be recovered and even improved by a full solution followed by two-step aging. The proper solution temperature is necessary to dissolve the deformed γ′ precipitates and allows optimum reprecipitation during next aging. The microstructure of the rejuvenated blade all shows bimodal distribution with coarse and fine γ′ precipitates. The microhardness is higher and more uniformly distributed than that of the service-exposed blade.     

高性能镍基粉末高温合金中γ′相形态致锯齿晶界形成机理研究

采用光学显微镜、场发射扫描电子显微镜和透射电子显微镜,系统研究了低错配度的第三代高性能粉末高温合金(FGH98I)在热处理条件下由合金晶界上γ′相不同析出行为造成的锯齿晶界。结果表明:在晶界上析出γ′相形态不同是锯齿晶界形成的主导因素。热处理时固溶冷却速率不同,晶界上析出的γ′相数量、尺寸和形态不同,对晶界锯齿形状有强烈影响。当冷却速率由0.1℃/s增大至10.8℃/s时,晶界锯齿振幅由4.02μm变为0.63μm,锯齿的波长则随冷却速率增大而变大。γ′相形态失稳的不同形状和尺寸是造成晶界锯齿振幅大小的主要因素。晶界两侧分布着不同密度的γ′相颗粒,也可使晶界发生位移形成波浪式小振幅锯齿晶界。根据实验结果,提出了有关锯齿晶界的形成模式。     

单晶γ-TiAl合金微观滑移机制的研究

针对单晶γ-TiAl合金微观滑移机制方面研究的不足,建立了单晶γ-TiAl合金单轴拉伸时晶体滑移几何模型,根据几何模型中各夹角之间的几何关系和由Weiss晶带法则给出的滑移方向,计算出了单滑移系中各个滑移方向上的Schmid因子;通过对比计算结果发现在设定条件下晶体更易产生滑移的方向为(001)[01-1]和(11-1)[110];在由主滑移系和交滑移系组成的双滑移系同时开动时,计算出了临界外加拉伸应变为0.633;通过数值模拟验证了所给出的单晶γ-TiAl合金单轴拉伸时的微观滑移机制的正确性。     

热暴露对γ-TiAl合金表面缺陷损伤容限的影响

研究了热暴露(700℃,10 000 h)对高强度全片层γ-Ti Al合金Ti-44Al-4Nb-4Hf-0.2Si-1B表面缺陷损伤容限的影响,采用扫描电子显微镜研究了热暴露导致γ-Ti Al合金的显微组织变化,并将之与在交变载荷下的表面短裂纹行为和长裂纹扩展行为联系起来.研究发现,在热暴露后,该合金的疲劳强度提高,且长疲劳裂纹启裂门槛值改善,但热暴露导致该合金短裂纹效应的尺寸范围明显增大.采用Kitagawa-Takahashi线图的形式总结和分析了实验结果,分析了热暴露引起的疲劳强化、疲劳失效的非安全短裂纹的尺寸变化以及长裂纹的启裂门槛值的变化,定量确定了热暴露对表面缺陷的损伤容限.长期热暴露所导致的材料内部应力释放、偏聚缓解、缺陷钝化显著影响裂纹尖端的应力状态,更有利于增大长裂纹的启裂抗力并减缓长裂纹的扩展速率.     

Magnetic measurement of strain-induced martensite formation in Fe–30Ni steel

This investigation focuses on deformation-induced plasticity in Invar-type steel alloys. The effect is being studied in an austenitic model alloy, containing 30 wt-% of nickel. Its temperature dependent mechanical properties are being presented. Furthermore, the martensitic phase content has been determined by magnetic means in an alloy with two ferromagnetic phases for the first time. The results show that the α′-martensite formation within the austenitic phase with primarily wavy glide mechanism allows an increase in ductility of around 10% at the M_sσ temperature of ?5°C. This is the point of maximum uniform elongation. Near the M_s temperature, a microstructure of 70 vol.-% deformation-induced α′-martensite can be achieved.     

Anti Cervix Cancer Activity of Co-immobilized Tumor Necrosis Factor-α and Interferon-γ

Tumor necrosis factor α （TNF-α） and interferon-γ （IFN-γ） are cytokines with strong antitumor activities. They were reacted with a photoactive arylazide-4-azidobenzoic acid, resulting in photoactive TNF-α and IFN-γ. The infrared （IR） spectra of these products showed the characteristic absorption of an azido group at 2127 cm^-1. By photo-immobilization, this modified TNF-α and IFN-γ were immobilized on polystyrene membranes for cell culture to prepare biomaterials. The micro-morphology of photoactive cytokines was observed with a scanning electron microscope （SEM）. The inhibitory effect on growth of Hela cells and inducing apoptosis activity of these two cytokines were analyzed by growth curve, transmission electron microscope （TEM） and fluorescence active cell sorter （FACS）. The results showed that co-immobilization of IFN-γ and TNF-α had significant inhibitory effect on growth of Hela cells, inhibitory rate up to 82%, and IFN-γ had obviously synergistic action.     

常压法间位聚芳硫醚砜酰胺酰胺的合成及表征

通过合成一种新的含二酰胺键和砜基的单体,将其与硫化钠进行常压溶液缩聚,合成出了间位聚芳硫醚砜酰胺酰胺(m-PPSSAA),其黏度达0.46g/dL,并通过红外、核磁(NMR)、紫外(UV)证实了其化学结构。用差示扫描量热分析(DSC)、热重分析(TGA)等手段对m-PPSSAA的热性能进行了表征,结果表明聚合物具有优良的热性能,通过溶解性试验表明m-PPSSAA能溶解于N,N-二甲基甲酰胺(DMF)、二甲亚砜(DMSO)、N-甲基吡咯烷酮(NMP)等溶剂,比聚苯硫醚(PPS)的溶解性好。