摘要：Electrochemical water splitting is regarded as the most promising approach to produce ***,the sluggish electrochemical reactions occurring at the anode and cathode,namely,the oxygen evolution reaction(OER)and the hydrogen evolution reaction(HER),respectively,consume a tremendous amount of energy,seriously hampering its wide ***,single-atom catalysts(SACs)have been proposed to effectively enhance the kinetics of these two *** this minireview,we focus on the recent progress in SACs for OER and HER *** classes of SACs have been reviewed,i.e.,alloy-based SACs,carbon-based SACs and SACs supported on other *** factors affecting the activities of SACs are also highlighted,including the inherent element property,the coordination environment,the geometric structure and the loading amount of metal ***,we summarize the current problems and directions for future development in SACs.

摘要：Semiconductor photocatalysts are extensively applied in environmental treatment and energy ***,one of their major disadvantages is their relatively low photocatalytic performance owing to the recombination of generated electron-hole *** presence of the phase junction is an effective way to promote the photocatalytic activity by increasing the separation efficiency of the electron-hole ***,extensive research has been conducted on the design of phase junctions of photocatalysts to improve their charge transfer properties and ***,for the design of an appropriate phase junction and the understanding of the mechanism of electron-hole separation,the development of the photocatalytic phase junction,including the preparation methods of the heterogeneous materials,is tremendously important and ***,the commonly used,externally induced phase transformation fabrication techniques and the primary components of the semiconductors are *** directions will still focus on the design and optimization of the phase junction of photocatalytic materials according to the phase transition with higher efficiencies for broadband responses and solar energy ***,the most popular phase transformation fabrication techniques of phase junctions are briefly reviewed from the application viewpoint.

摘要：这个问题赶出为线性变化时间的不明确的周期的描述符系统的稳定被重游。为线性变化时间的不明确的周期的描述符系统基于柔韧的稳定性的概念，为柔韧的稳定性的一个必要、足够的条件被提出。柔韧的稳定问题也被学习，相应必要、足够的条件用双系统的符号被给。获得的矩阵不平等条件能被转变到与一些免费矩阵的介绍的线性矩阵不平等一，它使分析和设计过程简单、可靠。

摘要：通过分子动力学模拟研究了纳米多晶316L奥氏体不锈钢在不同峰值应力下的高温蠕变变形行为和蠕变机制.数值模拟结果表明纳米多晶316L奥氏体不锈钢的高温蠕变变形是由位错、晶粒内部和晶界扩散以及晶界滑移之间的交互作用引起.在初始蠕变和稳态蠕变阶段,纳米多晶316L奥氏体不锈钢高温蠕变的主导性机制是晶粒内部和晶界的扩散以及晶界的滑移.在加速蠕变阶段,一些晶界被摧毁后,位错滑移成为纳米多晶316L奥氏体不锈钢的主要蠕变机制.这项工作旨在揭示纳米多晶316L奥氏体不锈钢的高温蠕变机理,为增强型抗蠕变316L奥氏体不锈钢的设计和制造提供指导.

摘要：The conversion of biomass-derived products to fine chemicals and fuels is extremely important for the utilization of renewable energy *** is not only a by-product formed during the hydrogenation of biomass-derived oxygenated chemicals,but also an inexpensive and nontoxic *** instability of solid catalysts for aqueous-phase reactions caused by metal leaching and the collapse of a catalyst support represents a significant *** this work,various catalyst stabilization strategies including the nanospace and interfacial confinements that prevent sintering and leaching of metal nanoparticles as well as modification methods for increasing the support stability are summarized and systemically *** addition,feasible approaches to designing stable and efficient heterogeneous catalysts for aqueous-phase reactions are proposed.

摘要：目的:Q345R是中国应用最多、最广泛的压力容器钢板材料,其低温韧性在国际上被严重低估。本文旨在通过大量试验研究,探明Q345R在低温下的实际韧性表征,得到其特有的冲击试验豁免曲线,并确定其合适的使用温度范围。创新点:1.基于大量低温试验数据,并考虑应变率的影响,得到了Q345R特有的冲击试验豁免曲线;2.采用主曲线方法代替纯冲击试验方法评价Q345R低温韧性,得到了基于主曲线方法的Q345R豁免曲线;3.通过比较两类韧性评价方法所得的豁免曲线,最终确定合适的Q345R使用温度范围。方法:1.利用试验获得大量的冲击试验数据(图3),通过计算K1(min)–t关系(图5)和Kc–T关系(图9),并考虑应变率的影响(公式(18)),得到Q345R特有的冲击试验豁免曲线(图10);2.利用试验方法获得Q345R的主曲线(图4),并用其代替原来的Kc–T关系,得到基于主曲线方法的Q345R豁免曲线(图14);3.比较两类方法的K1d–T关系(图13)和豁免曲线(图14)。结论:1.Q345R的低温韧性在国际上被严重低估;2.得到了Q345R特有的冲击试验豁免曲线及其合适的使用温度范围;3.主曲线方法的引入能进一步拓展Q345R的使用温度范围。

摘要：目的:设计制造低温的催化氢气燃烧器,并对其进行相关功能性测试。创新点:成功设计并制造出一个集成流量分配器的催化低温氢气燃烧器。方法:1.基于树状分叉方法,设计燃烧器的流量分配器,均匀分配气体到催化表面,并利用熔融沉积成型技术制备原型样机。2.基于测试结果,利用选择性激光熔化技术对燃烧器进行最优化设计。3.对设计的催化燃烧器的相关功能进行验证。结论:1.设计的低温催化燃烧器与传统的非催化燃烧器相比具有很多优势,尤其是实现了无焰均匀低温(约200°C)的产热;这一技术有望运用于化工领域的增材制造。2.本文不但用选择性激光熔融技术制备了最终产品,而且利用了熔融沉积成型技术进行快速的样机制备。3.催化剂多孔载体的调控和催化剂的负载方式研究有望进一步提升燃烧器的综合性能。

摘要：目的:固化变形问题是纤维增强复合材料结构件固化成形及应用过程中的一大阻碍。本文旨在综述引起固化变形的原因和机理,归纳和评价固化变形的控制方法,以及指出目前存在的问题与不足。方法:1.通过对国内外文献的大量阅读与分析,得到固化变形问题的产生机理及近年来的研究进展;2.通过对该领域论文的分类和归纳,总结出固化变形的主要控制策略,并分类讨论每项策略的控制措施。结论:1.固化变形的产生机理主要有热变形、化学收缩变形和模具作用3种。2.本文归纳了固化变形的五类控制方法:模具补偿、固化工艺优化、结构件优化设计、模具接触面优化以及开发新方法。3.针对各控制策略的优点,本文分析和总结了它们的适用场合以及控制效果。4.在固化变形的研究方面,目前仍然存在许多问题与不足。

摘要：目的:先导式截止阀可通过一个先导阀,利用流体在阀门前后自身的压差控制主阀的启闭,是一种新型节能型截止阀。本文探讨该阀在开启和关闭状态下、不同入口速度情况下和不同阀芯位置下的流动和汽蚀特性,为后期结构优化提供设计建议。创新点:1.分析先导式截止阀的阀芯上下表面压差的变化情况,验证其可行性和模型准确性;2.建立数值模型,对先导式截止阀在不同启闭状态和不同阀芯位移情况下进行流动和汽蚀分析。方法:1.通过数值模拟,分析阀芯上下表面的压差,并与现有文献进行比较,验证模型的准确性(图3);2.建立开启和关闭条件下的阀门模型,比较两种状态下该阀的流动和汽蚀特性(图4和5);3.建立不同入口速度条件下的阀门模型,比较分析速度对该阀的汽蚀情况的影响(图6);4.建立不同阀芯位置的阀门模型,比较分析不同阀芯位置下的速度和压力情况,进一步验证该阀的可行性,并分析阀芯位置对阀门汽蚀的影响(图7)。结论:1.在开启和关闭状态下,流速和汽含率在阀座底部靠近出口处达到峰值;2.入口速度更高的情况下,阀的开启速度更快,但汽含率并不一定同步上升;3.当阀芯处于低位置时,虽然对阀门出口处影响位置较小,但其压力梯度较大、汽含率较高,选取合适的弹簧刚度非常重要。

摘要：As the kinetically sluggish oxygen evolution reaction(OER)is considered to be a bottleneck in overall water splitting,it is necessary to develop a highly active and stable electrocatalyst to overcome this ***,we successfully fabricated a three-dimensional iron-dysprosium oxide co-regulated in-situ formed MOF-Ni arrays on carbon cloth(FeDy@MOF-Ni/CC)through a facile two-step hydrothermal *** studies demonstrate that the designed FeDy@MOF-Ni/CC catalyst requires an overpotential of only 251 mV to reach 10 mA cm-2 with a small Tafel slope of 52.1 mV ***,the stability declined by only 5.5%after 80 h of continuous testing in 1.0 M ***,a cell voltage of only 1.57 V in the overall water splitting system is sufficient to achieve 10 mA cm-2;this value is far better than that of most previously reported *** excellent catalytic performance originates from the unique 3D rhombus-like structure,as well as coupling synergies of Fe-Dy-Ni *** combination of lanthanide and transition metal species in the synthesis strategy may open entirely new possibilities with promising potential in the design of highly active OER electrocatalysts.