CO2对油田地下水环境中Q235钢和X70钢腐蚀行为的影响

为了探明辽河油田地下水环境中CO₂对Q235钢和X70管线钢的腐蚀规律,采用动电位极化技术及交流阻抗技术研究了不同CO₂浓度对该环境下两种钢腐蚀行为的影响,并利用光学显微镜对试样腐蚀界面进行表征。结果表明:随着CO₂浓度的增加,Q235和X70钢的交流阻抗图谱的半径均减小,腐蚀电流密度增大,腐蚀坑数量、深度和面积都增加,腐蚀敏感性增大。在低浓度CO₂环境下(CO₂含量为10%时),Q235钢的腐蚀敏感性比X70钢更高;而在高浓度CO₂环境下(CO₂含量为20%、40%、60%时),Q235钢的腐蚀速率反而较小,耐腐蚀性更好。     

多相流管输体系中水合物沉积机理研究进展

国内外对多相流管输体系中水合物沉积的研究虽然很多，但水合物沉积机理仍有待进一步研究。本文根据水合物沉积实验开展条件的不同，将多相流管输体系分为气体主导体系、油基体系、部分分散体系、水主导体系，总结了各体系的水合物沉积的主要机理，并提出了未来的发展方向。管输体系中水合物沉积机理包括水润湿沉积表面、水合物颗粒聚并、水合物的管壁膜生长、水合物颗粒的管壁粘附和水合物的颗粒着床沉积等。大多数学者认为：水合物的管壁膜生长是气体主导体系水合物沉积的主要机理；油基体系水合物沉积的主要机理是水合物颗粒的着床沉积；而部分分散体系和水主导体系的水合物沉积机理尚无统一定论，需进一步研究。多相流管输体系中水合物沉积研究未来的发展方向如下。①搭建全透明的流动环路，观测水合物在管路内实际的形成过程及沉积过程，对水合物沉积机理进行深入研究。②量化研究油水分层、油包水(或水包油)乳状液、自由水层对水合物沉积、堵塞的影响。③对于气体主导体系，除环状流和分层流外，有必要对段塞流、气泡流等其他常见的流型下沉积机理进行研究，重点在于开发一个综合模型来描述水合物沉积过程。④对于水主导体系，水合物形成过程出现的油水破乳的具体机理应是未来水合物沉积过程进行定量研究的方向。⑤国内外对垂直管、弯管及管阀件处水合物沉积堵塞理论研究较少，未来应着重这方面。     

汽车用非调质钢C38+N的研究

汽车用非调质钢C38+N既可以用作制造曲轴材料,亦可以用来生产发动机胀断连杆,采取优化化学成分（/%:0.36～0.40C,0.50～0. 65Si,1.40～1.55Mn,0.10～0.20Cr,0.015～0.020N,0.020～0.035S,≤0.025P,0.003～0.015Al）、喂S线控制硫化物含量等手段,生产的C38+N钢机械性能为Rp0.2506～544 MPa,Rm 854～879 MPa,A 12%～23.5%,Z 26%～30%,满足标准要求。     

C6H11NO/2TsOH型低共熔溶剂的制备及其催化氧化脱硫性能

通过加热溶解己内酰胺和对甲苯磺酸的混合物制备CC₆H₁₁NO/2TsOH型低共熔溶剂(DESs)，并对 C₆H₁₁NO/2TsOH进行红外和氢谱分析。以C₆H₁₁NO/2TsOH为萃取剂和催化剂，H₂O₂为氧化剂，催化氧化脱除模拟油中的硫化物。考察了反应温度、n(H₂O₂)/n(S)、C₆H₁₁NO/2TsOH用量和不同硫化物类型对脱硫效果的影响。结果表明：在低共熔溶剂加入量为1.0 g、温度为60 ℃、n(H₂O₂)/n(S)=4、模拟油体积为5 mL的反应条件下，C₆H₁₁NO/2TsOH对二苯并噻吩(DBT)、4，6-二甲基二苯并噻吩(4,6-DMDBT)和苯并噻吩(BT)的脱除率分别为97.32%、86.60%、77.80%；C₆H₁₁NO/2TsOH循环使用5次，催化活性无明显下降；动力学分析表明，作用下的氧化脱硫过程符合一级反应动力学。     

Li ion conduction of perovskite Li0.375Sr0.4375Ti0.25Ta0.75O3 and related compounds

In this work, perovskite-structured Li_0.375Sr_0.4375M_0.25N_0.75O₃ (M=Ti, Sn, N=Nb, Ta) solid electrolytes were synthesized by conventional solid state reaction method. Phase compositions, fractured morphologies and conductivities of these compounds were investigated by X-ray diffraction, scanning electron microscope and AC-impedance spectroscopy, respectively. X-ray diffraction analysis confirms that all of Li_0.375Sr_0.4375M_0.25N_0.75O₃ (M=Ti, Sn, N=Nb, Ta) ceramics present perovskite structure. Pure Li_0.375Sr_0.4375Ti_0.25Ta_0.75O₃ and Li_0.375Sr_0.4375Sn_0.25Ta_0.75O₃ perovskite ceramics were obtained. But impurities were detected in Li_0.375Sr_0.4375Ti_0.25Nb_0.75O₃ and Li_0.375Sr_0.4375Sn_0.25Nb_0.75O₃. Among all investigated compounds, Li_0.375Sr_0.4375Ti_0.25Ta_0.75O₃ shows the highest total ionic conductivity of 2.60 × 10^?4 S cm^?1 at room temperature and the lowest activation energy of 0.347 eV. Conductivities of Li_0.375Sr_0.4375Sn_0.25Ta_0.75O₃ and Li_0.375Sr_0.4375Sn_0.25Nb_0.75O₃ were 4.4 × 10^?5 S cm^?1 and 1.82 × 10^?6 S cm^?1, respectively. Their conductivities were much lower than Li_0.375Sr_0.4375Ti_0.25Ta_0.75O₃ and Li_0.375Sr_0.4375Ti_0.25Nb_0.75O₃.     

Zinc-Deficiency Induced g-C3N4 Nanosheets: Photocatalytic Nitrogen Fixation Study and Carrier Dynamics

Catalysis Letters - g-C3N4 has great application prospect in the field of photocatalytic nitrogen fixation owing to the advantages of abundant raw materials, low toxicity, low consumption, high...     

傲牛铁矿三采区充填体稳定性及间柱回采顺序研究

随着傲牛铁矿三采区矿柱的回采，矿房充填体失去矿柱的侧压限制且暴露面积越来越大，充填体的受力条件发生改变，影响其稳定性，为此需要进行充填体的稳定性及回采顺序优化研究。结合傲牛铁矿的矿岩物理力学性质和矿柱回采方法，对矿房充填体建立力学模型，分析充填体在开采时受力的稳定性，计算充填体的极限自立高度；同时根据现场情况，提出了2种间柱整体开采顺序方案和2种中段间柱回采顺序方案，并对其进行了数值计算分析。计算结果表明：在整体开采间柱顺序上，从下至上开采最优，应力集中程度低，安全性高；在265 m中段间柱开采顺序上，先开采①、③、⑤间柱，再回采②、④间柱，位移变化较小。研究成果为现场的间柱回采提供了理论依据。     

Carbon vacancies improved photocatalytic hydrogen generation of g-C3N4 photocatalyst via magnesium vapor etching

Vacancies engineering was widely reported as the promising strategy for the improvement of the photocatalytic performance of semiconductor photocatalysts. In current work, carbon vacancies are constructed successfully in graphitic carbon nitride (g-C₃N₄) photocatalyst via magnesium vapor etching. Experimental results show that the formed carbon vacancies in g-C₃N₄ photocatalyst can significantly improve the photocatalytic H₂ generation performance. XRD, FTIR, SEM/TEM, XPS and PL characterization data are employed to evidence the construction of carbon vacancies, which are revealed to be the reason for the enhancement of photocatalytic H₂ evolution. This work develops an alternative route to construct carbon vacancies in g-C₃N₄ materials and gives an insight into the influence of vacancies on the photocatalytic performance of photocatalysts.     

Performance enhancement of energy extraction capability for fuel cell implementations with improved Cuckoo search algorithm

This paper addresses an improved optimization method to enhance the energy extraction capability of fuel cell implementations. In this study, the proposed method called Dynamic Cuckoo Search Algorithm (DCSA) is tested in a stand-alone fuel cell in order to control the system power under dynamic temperature response. In the operational process, a fuel cell is connected to a load through a dc-dc boost converter, and DCSA is utilized to adjust the switching duration in dc-dc converter by using voltage, current and temperature parameters. In this way, it controls the output voltage to maximize power delivery capability at the demand-side and eliminates the drawback of conventional cuckoo search algorithm (CSA) which cannot change duty cycle under operating temperature variations. In this regard, DCSA shows a significant improvement in terms of system response and achieves a more efficient power extraction than the conventional CSA method. In order to demonstrate the system performance, the stand-alone fuel cell system is constructed in Simulink environment via a processor-in the-loop (PIL) based digital implementation and analyzed by using different optimization methods. In the analysis section, the results of the proposed method are compared with conventional methods (perturb&observe mppt, incremental conductance mppt, and particle swarm optimization). In this context, convergence speed and efficiency analysis for both methods verify that the DCSA gives original results compared to conventional methods.