扩散层PTFE载量对被动式直接甲醇燃料电池性能的影响

在被动式直接甲醇燃料电池(DMFC)的扩散层中,处理好水、气、电子的通道对电池性能有着十分重要的作用.本研究分别用质量百分比浓度为10%、20%、30%、40%的PTFE乳液进行疏水处理的碳布组装成被动式DMFC以及测试系统.通过稳态电流-电压极化曲线法和交流阻抗法,研究了扩散层中的不同PTFE载量对被动式DMFC电化学性能的影响.研究结果表明,电池开路电压随着阳极扩散层中PTFE载量的增加而上升,电池内阻也随着扩散层中PTFE载量的增加而增加.在阳极,电池性能随着扩散层中PTFE载量的增加而下降,在阴极,用10%PTFE乳液处理的碳布对被动式DMFC性能表现最好.     

Representation learning: serial-autoencoder for personalized recommendation

Nowadays, the personalized recommendation has become a research hotspot for addressing information overload. Despite this, generating effective recommendations from sparse data remains a challenge. Recently, auxiliary information has been widely used to address data sparsity, but most models using auxiliary information are linear and have limited expressiveness. Due to the advantages of feature extraction and no-label requirements, autoencoder-based methods have become quite popular. However, most existing autoencoder-based methods discard the reconstruction of auxiliary information, which poses huge challenges for better representation learning and model scalability. To address these problems, we propose Serial-Autoencoder for Personalized Recommendation (SAPR), which aims to reduce the loss of critical information and enhance the learning of feature representations. Specifically, we first combine the original rating matrix and item attribute features and feed them into the first autoencoder for generating a higher-level representation of the input. Second, we use a second autoencoder to enhance the reconstruction of the data representation of the prediciton rating matrix. The output rating information is used for recommendation prediction. Extensive experiments on the MovieTweetings and MovieLens datasets have verified the effectiveness of SAPR compared to state-of-the-art models.     

多糖涂覆的氧化铁纳米粒子的合成及其药物递送应用研究进展

近年来,氧化铁纳米粒子(Iron Oxide Nanoparticles,IONPs)由于具有超顺磁性、生物相容性、比表面积大、易分离等特点而备受科学界关注.然而,裸露的IONPs容易聚集和氧化而失去其应有的特性,采用多糖进行涂覆不仅能提高IONPs的稳定性和生物相容性,还能通过多糖与其他生物活性物质结合,赋予INOPs新的功能.多糖涂覆的IONPs充分结合了多糖的生化特性与磁芯的理化特性,在药物递送中展现出巨大的应用潜力.本文综述了多糖涂覆IONPs的合成方法、合成过程的影响因素、多糖与IONPs的结合机理及其在药物递送中的应用,最后对多糖涂覆的IONPs的合成及其在药物递送方面的应用进行了总结和展望.     

磨溪气田气水同采井水气比变化特征及机理

底水气藏防止底水锥进时通常采用避射水层的生产方式，但四川部分气田的开发则采用射开气、水层且气水同采的生产方式。为进一步了解其生产动态特征与储层特征之间的关系，通过避射水层和气水同采2种模式特征之间的对比，总结出气水同采井的水气比曲线有平稳段、缓慢上升段、快速上升段、下降段和跳跃段5种类型，分析了每种类型对应的储层特征，绘制了水气比曲线变化图版；确定了研究区水气比线性分段函数斜率的取值范围。现场应用证明气水同采的生产动态特征与储层特征基本一致，表明该图版实用性强，有助于正确认识底水气藏地层水活动规律，而储层内部气、水两相渗流变化需要进一步研究。