CO2在岩石孔隙介质内相态特征的超声波探测与分析

岩心孔隙介质内的流体相态特征研究是实施CO2埋存及驱油的重要基础。本实验建立了一套超声波测试岩心孔隙介质内流体相态特征的新方法。通过声波探头及夹持器堵头一体化、端面抛光等手段,将声波探头直接作用于孔隙介质,解决了传统测试方法中探头不能承压、声波沿钢体绕射、能量损失过大等诸多问题,同时,自行研制了孔隙介质内流体相态探测声波发射、接收及信号处理软件,提高了测试精度,推动了超声波技术与油气田开发技术的交叉结合与应用发展。以吉林油田某区块天然岩心为例,测试了孔隙介质内CO2的相态特征,分析了孔隙介质对流体相态的影响。结果表明：该方法灵敏度高,数据可靠,避免了常规PV T 方法中忽视孔隙介质影响的误差。     

冷喷涂辅助原位合成FeCoxCrAlCu高熵合金涂层组织性能研究

利用冷喷涂辅助原位合成高熵合金涂层的方法,在45_^#钢基体表面成功制备出不同Co含量的FeCo_xCrAlCu(x=0,0.5,1,1.5,2)高熵合金涂层。通过XRD、SEM、EDS、TEM、显微硬度计、磨料磨损试验机、电化学工作站等设备,检测分析了Co含量的变化对合金涂层相结构、显微组织,硬度、耐磨性及耐腐蚀性的影响。结果表明：合金涂层是由简单的FCC+BCC双相混合结构组成,Co含量的改变对涂层相组织的数量影响不大;随着Co含量的增加,合金涂层中显微组织的枝晶数目增加,并且得到明显粗化,通过面扫得显微组织中枝晶内富集Fe,Cr,Co元素,枝晶间富集Cu元素,Al均匀的分布在整个涂层中;随着Co含量的增加,硬度先增加后减小,在Co=1时合金涂层硬度达到最大为555.6HV;合金涂层中最小的摩擦系数为0.361;在3.5wt.%NaCl腐蚀介质中,合金涂层相比与45_^#钢基体具有较正的自腐蚀电位(E_corr=-0.325V),说明涂层耐腐蚀性比基体好。     

Thermogravimetric analysis of microalgae combustion under different oxygen supply concentrations

Recently, studies of microalgae in China have increased a lot because of their obvious advantages over other biological fuels. In this paper, the combustion behavior of Chlorella vulgaris (a genus of unicellular green microalgae) was investigated in a thermogravimetric analyzer (TGA) from room temperature to 800 °C in O₂/N₂ atmospheres. The effects of different oxygen concentrations (20, 50, 60, 80 vol.%) and different heating rates (10, 20 and 40 °C min⁻¹) on the combustion processes of C. vulgaris had been studied. The results indicated that the combustion processes of C. vulgaris could be divided into three stages. The oxygen concentrations and heating rates had important effects on the main combustion processes of C. vulgaris. The iso-conversional method involving Flynn–Wall–Ozawa (FWO) and the Kissinger–Akahira–Sunose (KAS) methods were used for the kinetic analysis of the main combustion process. The results indicated that, when the oxygen concentration varied from 20 to 80 vol.%, the value of activation energy increased respectively from 134.03 to 241.04 kJ mol⁻¹ by using FWO method and from 134.53 to 242.33 kJ mol⁻¹ by KAS method. Moreover, the optimal oxygen concentration for C. vulgaris combustion was 25–35 vol.%_.