Hydrogenation process in multiphase alloys of Ti-Zr-Mn-V system on the example of Ti42.75Zr27Mn20.25V10 alloy

The influence of phase composition and microstructure of Ti_42.75Zr₂₇Mn_20.25V₁₀ alloy on its hydrogenation kinetic and phase composition of hydrogenated product was studied. It is established that the process of dissociation of hydrogen molecules begins on the surface of Laves phase crystallites. The dissolution of atomic hydrogen in the material volume leads to the formation of cracks in the intermetallic crystallites, which further appear as additional centers of dissociation of hydrogen molecules and noticeably accelerate the diffusion of hydrogen into the bulk material. It was shown that the Laves phase acts as a donor of atomic hydrogen for the BCC solid solution during hydrogenation of two-phase structure, initiating intensive hydrogenation of the BCC phase at room temperature.     

Computation of concentrations of characteristic atoms of alloys in BCC structure

In this paper,taking Nb-Mo alloy system as an example,the equations of concentration of characteristic atoms of alloys in BCC structure were obtained on the basis of the idea of systematic science of alloys and the number of coordination atoms.The concentrations of characteristic atoms in B2-NbMo type ordered alloys were calculated as functions of ordering degree(s) and composition xMo.When s=smax,the concentrations of characteristic atoms of stoichiometric B2-NbMo intermetallic compound are equal to that o...     

（V30Ti35Cr25Fe10）97．5Si2．5合金的结构与吸放氢性能

采用XRD，SEM和PCT测试研究了（V30Ti35Cr25Fe10）97.5Si2.5（at％）合金的组织结构与吸放氢性能。结果表明：合金由BCC相和C14 Laves相组成，BCC相含量为75％，晶胞参数为α=0．3021nm，Laves相含量为25％，晶胞参数为α=0．4920nm和c=0．7996nm。由于含有大量的Laves相，合金具有良好的活化性能，室温下不需孕育期就可以快速吸氢，5min内达到吸氢饱和状态，饱和吸氢量达到2．98％（质量分数，下同）。在一定氢压下，合金的容量可由合金中BCC相和Laves相的容量按组分的含量进行线性组合而成。     

非有效决策单元的效率研究

首先研究了决策单元的规模效率,然后用传统的DEA模型和超效率DEA模型研究了非有效决策单元,对非CCR有效决策单元,模型（1）和模型（3）等价,对非BCC有效决策单元,模型（2）和模型（4）等价．     

基于DEA的部队海训绩效分析

为提高我军的海上战斗能力,采用数据包络分析法（Date Envelopment Analysis,DEA）对部队海训绩效进行有效评价。根据某团海训的各要素建立评估指标体系,采用DEA的C2R和BCC模型相结合的方法,选取了实用性和操作性很强的指标体系,对该团的整体训练情况做了分析,为＂评先评优＂工作提供了理论依据。结果表明,该方法克服了传统方法中的主观因素的影响,使得评价结果更加客观,更能反映该团训练的真实情况。但还需考虑其他随机因素,以确保实例分析的可行性和科学性。     

Ti1.0Mn0.9V1.1基合金的微观结构和电化学性能

“与Laves相相关的BCC固溶体”是一个新概念,由此发展起来的新型钛基BCC合金贮氢能力已经达到了2.2%(质量分数)。Akiba等用TEM(透射电子显微镜)方法观测TiMnV合金的BCC相和C14相的交界面,发现存在一个厚度为10 nm的薄层。通过EDX(电子探针X射线显微分析)方法观测,这个薄层物质的组成为Ti1.0Mn0.9V1.1,但是Ti1.0Mn0.9V1.1却不具备电化学活性。在此基础上,从Ti1.0Mn0.9V1.1出发,通过组成元素的部分取代,使储氢性能优良的Ti1.0Mn0.9V1.1具有电催化活性,对Ti1.0Mn0.9V1.1系合金的结构和电化学性能进行研究,Ti1.0Mn0.9V1.1系合金有可能成为MH-Ni蓄电池潜在的高温负极材料。     

Effects of V content on hydrogen storage properties of V–Ti–Cr alloys with high desorption pressure

Hydrogen storage is one of the most important issues to realize hydrogen society especially for on-board usage. Recently, high-pressure metal hydride (MH) tank attracts many attentions due to its high volumetric hydrogen storage density and relatively easy heat management. To emphasize its merits, further improvements of properties of MH, such as capacity, hydrogen desorption capability at low temperature and durability, are required. In this paper, V–Ti–Cr alloys of V-rich compositions were investigated with perspective of increasing of hydrogen desorption pressure and durability. In both of 60at%V–Ti–Cr and 80at%V–Ti–Cr alloys, good relationship between hydrogen desorption pressure and Ti content was observed. In comparing with 60at%V–Ti–Cr alloys, 80at%V–Ti–Cr alloys showed good durability. It is quite notable that relationship between limitation line (upper substitution limit of Ti by Cr without degradation of hydrogen capacity) and desorption pressure for V–Ti–Cr ternary system with V-rich composition is clarified. And also, it is revealed that in the case of V–Ti–Cr ternary system, not only Ti/Cr ratio but also V content is important factor to obtain alloys with high hydrogen desorption pressure. 75at%V–5at%Ti–Cr as-cast sample showed good durability, hydrogen desorption capability at low temperature and relatively high effective hydrogen capacity simultaneously.     

考虑需求响应虚拟机组和碳交易的含风电电力系统优化调度

在智能电网和低碳电力的背景下,提出一种考虑需求响应虚拟机组和碳交易的含风电电力系统优化调度模型。首先,将需求侧资源分为可调度资源和不可调度资源,在可调度资源中分别建立了价格需求响应虚拟机组和激励需求响应虚拟机组模型,并分析了两种虚拟机组的运行特点;其次,在优化调度模型中引入碳交易,并提出系统碳减排目标的概念及阶梯型碳排放权价格,分析其对碳排放量的制约情况。在此基础上,引入功率平衡约束、机组出力及爬坡约束、虚拟机组运行约束等,建立了以碳交易成本、火电机组发电成本和虚拟机组运行成本为目标的新型低碳经济调度模型,采用细菌群体趋药性(BCC)算法对模型进行求解。通过仿真算例对不同场景下系统的风电消纳情况和系统的综合运行成本进行了分析。算例结果验证了模型及求解方法的可行性及优越性。     

基于改进细菌群体趋药性算法的电力系统无功优化

建立了无惩罚因子策略的数学模型,并应用改进细菌群体优化(bacterial colony chemotaxis,BCC)算法进行无功优化。该模型利用可行细菌的占比指导细菌向可行空间搜索或最小网损空间搜索,快速搜索到可行的最优值。在基本BCC算法中引入速度、感知范围的动态调整以及高斯变异机制以提高寻优精度;同时引入映射因子以改善BCC算法解决离散域问题的性能。算例结果表明,改进BCC算法具有较好寻优性能,结合无惩罚因子策略的数学模型能快速得出合理的无功优化策略。     

Structure and hydrogen permeability of V–15Ni alloy

The structure of the V–15Ni at.% alloy before and after hydrogen permeability tests was investigated by means of XRD and SEM with EDS analysis. We have found that decomposition of supersaturated V-based solid solution with variable Ni content occurred during testing. The volume fraction of the solid solution decreased and the fraction of V₃Ni phase increased during permeability testing, thus bringing the alloy to nearly equilibrium. The membrane without Pd coating showed satisfactory hydrogen fluxes with a significant impact of the surface dissociation rate of hydrogen. The shape of hydrogen permeation curves at the downstream side of the membrane at various temperatures was unusual. We attribute it to the high concentration of dissolved hydrogen in the metal lattice and its effect on the hydrogen diffusivity and solubility. In addition, the multiphase structure with non-uniform distribution of nickel both between the phases and within the BCC solid solution (and, consequently, different hydrogen concentrations) may cause dilatation or compressing effect on neighbouring micro-volumes of the alloy.