三峡直流换流站等值附盐密度取值的研究

针对宜昌市大气污染和三峡换流站站址附近污秽状况,结合短峡换流站附近交、直流设备盐密测量和运行经验以及宜昌气候特征,提出了三峡换流站适用的等值附盐密度值,并在此基础上提出了交、直流户外设备外绝缘的有关结构参数。     

Vanadium Doping Enhanced Electrochemical Performance of Molybdenum Oxide in Lithium‐Ion Batteries

Molybdenum trioxide (MoO₃) suffers from poor conductivity, a low rate capability, and unsatisfactory cycling stability in lithium‐ion batteries. The aliovalent ion doping may present an effective way to improve the electrochemical performances of MoO₃. Here, it is shown, by first‐principle calculations, that doping MoO₃ with V by 12.5% can modulate significantly electronic structure and provide a small diffusion barrier for enhancing the electrochemical performance of MoO₃. The ultralong Mo_0.88V_0.12O_2.94 nanostructures, which retain the h‐MoO₃ structure and present an exceptionally high conductivity and fast ionic diffusion due to the substitution of V, facilitating lithiation/delithiation behavior, and induce a fine nanosized structure with a reduced volume change are prepared. As a result, the stress and strain are alleviated during the Li‐ion intercalation/deintercalation processes, improving the cycling stability and rate capability. Such a large improvement in the electrochemical properties can be ascribed to the stabilizing effect of V, the small migration energy barrier, and short diffusion path, which arise from the introduction of V into MoO₃. The unique engineering strategy and facile synthesis route open up a new avenue in modifying and developing other species of electrode materials.     

High‐Yield Electrochemical Production of Large‐Sized and Thinly Layered NiPS3 Flakes for Overall Water Splitting

Achieving large‐sized and thinly layered 2D metal phosphorus trichalcogenides with high quality and yield has been an urgent quest due to extraordinary physical/chemical characteristics for multiple applications. Nevertheless, current preparation methodologies suffer from uncontrolled thicknesses, uneven morphologies and area distributions, long processing times, and inferior quality. Here, a sonication‐free and fast (in minutes) electrochemical cathodic exfoliation approach is reported that can prepare large‐sized (typically ≈150 µm²) and thinly layered (≈70% monolayer) NiPS₃ flakes with high crystallinity and pure phase structure with a yield ≈80%. During the electrochemical exfoliation process, the tetra‐n‐butylammonium salt with a large ionic diameter is decomposed into gaseous species after the intercalation and efficiently expands the tightly stratified bulk NiPS₃ crystals, as revealed by in situ and ex situ characterizations. Atomically thin NiPS₃ flakes can be obtained by slight manual shaking rather than sonication, which largely preserves in‐plane structural integrity with large size and minimum damage. The obtained high quality NiPS₃ offers a new and ideal model for overall water splitting due to its inherent fully exposed S and P atoms that are often the active sites for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Consequently, the bifunctional NiPS₃ exhibits outstanding performance for overall water splitting.     

FTO反应Fe基催化剂活化与活性相研究进展Q

综述了铁基催化剂对合成气一步法制备低碳烯烃反应（FTO）的研究进展，总结了活化过程、辨析了活性相对FTO反应性能的影响。铁基催化剂具有成本低、易得、操作温度范围宽等诸多优点而备受关注。然而，物相复杂、活性相不确定、反应性能有待提升等诸多缺点也是Fe基催化剂现今存在的主要问题。活化过程与气氛直接相关，且整体呈现由表相向体相递进反应的趋势。还原气中含CO时，催化剂表相会生成活性物相FeCx，且随着温度和反应的进行逐渐发生ε-Fe2C→ε′-Fe2.2C→χ-Fe2.5C→θ-Fe3C的反应，θ-Fe3C已被报道具有很好的FTO反应性能。本文对近10年关于Fe基FTO反应催化剂活化和活性相的研究发展进行了浅显的综述，力求寻求这些研究中的规律性知识，以期对未来FTO反应铁基催化剂的反应性能研究提供帮助。     

基于EtherCAT从站的风电机组扩展I/O系统设计

针对目前在风电机组中功能日益丰富,以及硬件I/O点的需求量也越来越大的问题,本文提出了基于EtherCAT从站模式的扩展I/O系统的设计方法。系统的I/O硬件接口采用了FSMC数据线复用方式的PDI接口;所开发的系统软件和XML文件配点在搭建的EtherCAT从站平台上进行了测试。测试结果表明,主控扩展I/O系统能够实现模拟量输入输出、数字量输入输出等功能,可以满足风电机组的功能需要。     

Effects of Dual-Phase Region Quenching Treatment on Microstructure and Mechanical Properties of 24CrNiMo Low-Alloy Steel Prepared by Selective Laser Melting

Herein, 24CrNiMo low-alloy steel is successfully prepared using selective laser melting (SLM) technology. Effects of dual-phase region quenching treatment on microstructure and mechanical properties of SLM 24CrNiMo low-alloy steel are analyzed. The results show that after three kinds of dual-phase region quenching treatment, different martensite–ferrite dual-phase microstructure of the as-quenched alloy steel is obtained. In the range of austenitizing temperature from 760 to 820 °C, the content and size of the ferrite decrease; on the contrary, the content and size of the martensite increase. Furthermore, with the austenitizing temperature increasing, the morphology of the ferrite gradually changes from acicular ferrite + polygonal ferrite to acicular ferrite, while the lath characteristics of the martensite become more and more obvious. For electron backscatter diffraction results, with increasing the quenching temperature, the crystallographic morphology gradually changes from columnar grains to equiaxed grains; meanwhile, the extreme value of texture strength and the average size of grains are both decreased. When the austenitizing temperature is 820 °C, the microhardness and tensile strength of the as-quenched alloy steel are much higher than that of the as-deposited alloy steel.     

316L不锈钢表面激光熔覆钴基合金组织及锌蚀机理

采用半导体激光器在316L不锈钢表面制备钴基合金熔覆层,对激光熔覆层的组织形貌、成分、结构及锌蚀机理进行了系统研究.结果表明,选择优化的激光辐照工艺参数,获得的钴基合金熔覆层表面平整、无裂纹、与基材呈良好的冶金结合.钴基合金熔覆层主要由γ-Co,M₂₃C₆及耐腐蚀性能优异的Laves相Co₃Mo₂Si和少量硬质耐磨相Co₆W₆C组成.在460℃熔融锌中腐蚀试验表明,钴基合金熔覆层的锌蚀机理为选择性腐蚀,熔覆层表层出现一层亮白色腐蚀过渡层,在过渡层内钴基固溶体基体优先发生腐蚀,导致Laves相剥落,从而形成了锌液对钴基合金熔覆层的进一步腐蚀.     

粘土矿物疏水改性研究现状及发展

黏土矿物可广泛用于有机高分子材料和复合材料,黏土矿物疏水改性是黏土矿物最重要的深加工技术之一,疏水改性后的黏土矿物有着更广泛的应用前景。介绍了黏土疏水改性的改性方法、工艺、改性药剂剂、改性设备、改性效果表征的研究现状及存在问题,提出了黏土矿物疏水改性技术发展方向,为黏土矿物的应用提供参考依据。     

聚苯并咪唑在高温质子交换膜燃料电池中的应用研究进展

简要介绍了一类高性能聚合物—聚苯并咪唑的制备方法及其在高温质子交换膜燃料电池中的应用研究进展;阐述了磷酸掺杂聚苯并咪唑膜的质子传导机理,探讨了磷酸掺杂率对聚苯并咪唑膜的力学强度和质子导电率等性能的影响规律;并对今后磷酸掺杂聚苯并咪唑质子交换膜研究领域需要解决的关键问题进行了讨论.     

氢抑制条件下的有机质热演化动力学模型——以三塘湖盆地芦草沟组为例

三塘湖盆地马朗凹陷芦草沟组烃源岩含有较多的富氢组分,有机质的热演化受到氢抑制。为了模拟氢抑制背景下的有机质热演化史,在经典的Sweeny和Burham Easy%R_o时-温双控化学动力学模型基础上,本文考虑氢抑制对有机质热演化的影响,根据氢指数调节反应活化能,建立了描述有机质热演化的时-温-氢抑制多控化学动力学模型。研究结果表明,芦草沟组氢抑制对R_o的贡献值为0.2%左右;由于氢抑制的影响,芦草沟组烃源岩进入生烃门限和开始大量生烃的时间均被延迟。文中新建立的化学动力学模型可以应用于各种类型干酪根的有机质热演化史模拟,其精度更高、应用范围更广。