泽蛙(Rana limnocharis)不同生活周期的生理生态研究

本文报道了泽蛙不同生活周期的生理生态特征:①繁殖期(5月)的耗氧量最大;繁殖期(8月)次之;冬眠期(1月)最小、只占5月的39.38%、8月的54.20%。②肾上腺皮质细胞直径和核直径繁殖期较长,冬眠时显著缩短。③觅食期(10月)肝含水量最多,冬眠时肝含水最少。④与耗氧量降低相适应,冬眠时RBC数目、Hb含量,RBC直径明显低于繁殖期,觅食期。⑤冬眠时,主要能量供给为活动季节里积累在肝脏与脂肪体中的营养物质。     

A novel bimetallic RuFe nanocluster to enable highly efficient oxygen reduction in zinc-air batteries

Zinc-air batteries (ZABs) have the advantages of high energy density and safety but their large-scale application is hindered by sluggish kinetics of four-electron aqueous O₂ redox reactions. Widely used Ruthenium (Ru)-based catalysts possess intrinsic oxygen evolution catalytic activity but suffer from insufficient oxygen reduction reaction (ORR) performance. Herein, to optimize the ORR activity of Ru-based catalyst, an iron (Fe)-coordinated, bimetallic RuFe cluster is constructed and homogeneously dispersed within nitrogen (N)-doped carbon layers (denoted as RuFe@NC). Benefitting from the optimized ORR activity and more active site exposure, the RuFe@NC exhibits superior ORR activity with a half wave potential (E_1/2) of 0.88 ?V higher than that of Pt/C (0.82 ?V). Accordingly, the RuFe@NC-based ZAB outperforms the Pt/C ?+ ?IrO₂-based device, presenting a reduced polarization of 0.7 ?V and an enhanced cycling lifetime of 50 ?h at 10 ?mA ?cm^?2. Moreover, the optimized structural design ultralow Ru loading (0.013 mg_Ru cm^?2) overcomes the cost barriers and demonstrates its high practicality. This bimetallic RuFe nanocluster opens a new way for future design of more efficient and stable catalytic systems.     

Electrolyte materials for intermediate-temperature solid oxide fuel cells

Solid oxide fuel cells (SOFCs) directly convert chemical energy that is stored in a wide range of fuels into direct current electricity, with high efficiency and low emissions, via a series of electrochemical reactions at elevated operating temperatures (generally 400–1000 °C). During such an energy conversion process, the properties of electrolyte materials determine the working principle and operating temperature of the SOFC. When considering the cost and stability, lowering the operating temperature is critical, and this has become one of the developing trends in SOFC research. The key point for realizing a reduction in operating temperature is to maintain low ohmic resistance of the electrolyte and low polarization resistance of the electrodes. In practice, the mechanical and chemical stability of the electrolyte is also a big concern. According to their differences in ion conduction mechanisms, there are three main types of electrolyte material available, namely, oxygen ion-conducting, proton-conducting, and dual ion-conducting electrolytes. In this review, we give a comprehensive summary of the recent advances in the development of these three types of electrolyte material for intermediate-temperature SOFCs. Both conductivity and stability are emphasized. In conclusion, the current challenges and future development prospects are discussed.     

Low-dimensional catalysts for oxygen reduction reaction

Developing highly efficient electrocatalysts to facilitate the sluggish cathodic oxygen reduction reaction (ORR) is a key challenge for high-performance fuel cells. Low-dimensional materials have attracted great attention recently because of their unique structure and properties. In this review, the application of zero-dimensional (0D), one‐dimensional (1D), and two‐dimensional (2D) materials in ORR are discussed and particular attention is given to the relationship between their structure and the ORR activity. Graphene-based materials, transition metal dichalcogenides, transition metal oxide, nanotubes, nanoribbons, nanowires, and single-atom ORR catalysts are introduced and classified by their geometric dimension.     

YBa_2Cu_3O_(7-δ)超导体在不同气氛中的高温相变

本文给出了在空气、真空和流动氮气的环境中,利用X-光跟踪监测YBa_2Cu_3O_(7-δ)高T_c超导体的X-光衍射峰的两个主要峰(130)/(101)和(031)峰的相对强度随温度的变化关系。结果表明,环境对高温相变温度及相变方式有很大的影响。并提出了“可动氧”模型。     

硫酸溶液中铂电极表面氧吸附过程的光电子能谱研究

硫酸溶液中铂电极表面氧吸附过程的光电子能谱研究徐富春，陈声培，薛国庆，孙世刚（分析测试中心，化学系，物化所，固体表面物理化学国家重点实验室，甘肃张掖师专化生系）电催化反应包含一系列表面吸附与脱附过程［１］．这些过程与电极表面结构密切相关。因此，深入研...     

O2在Cu-Al-MCM-41上NO选择性还原反应中的作用

考察了O2对Cu-Al-MCM-41催化剂上NO选择性还原反应和吸附性能的影响. 结果表明,O2在反应中有相反两方面的作用一方面为NO氧化及催化剂活性中心的氧化还原循环提供氧物种;另一方面,直接完全氧化C3H6,引起还原剂的耗尽.     

金属氧化物对软质PVC阻燃性能的影响

作为五大树脂之一的PVC，其阻燃的意义是十分重要的。为了进一步扩大聚氯乙烯的应用领域，提高软质聚氯乙烯的阻燃及抑烟性能，选择金属氧化物对软质聚氯乙烯的阻燃性能的影响作为研究内容，利用这些金属氧化物的物理性质和热分析数据，对其阻燃机理进行了初步探讨。研究发现在软质聚氯乙烯中阻燃效果较好的金属氧化物大都为过渡金属的氧化物，一般熔点较低；其阻燃机理主要是通过对含卤阻燃剂的协同阻燃表现出来的，阻燃效果随添加量的增加而提高，但在添加至一定分量后，氧指数变化出现平台。     

用线算图分析富氧燃烧锅炉的热力状态

本文提出用线标图的方法分析应用富氧燃烧技术后锅炉的空气量、烟气量、排烟热损失及由此可达到的节煤率;同时还利用线算图对不同参数锅炉的辐射换热及其与工质各吸热量之间的关系进行了热力分析?     

广东省异常血红蛋白研究X:一例HbG Taipei的一级结构与功能研究

1986年在暨南大学新生普查中,发现一例电泳迁移率属HbG组的异常血红蛋白。先证者无临床症状。我们用快原子轰击(FAB)质谱枝术测定其变异肽段的氨基酸顺序,确证它是HbG Taipei(α_2β_2~(22)Glu→Gly)。仿Benesch法测定它的氧平衡曲线,发现其氧亲和力与HbA相同,2,3—DPG对它的效应亦正常。