前景理论视角下PPP项目共享风险管理演化及仿真分析

PPP项目往往特许期较长,复杂和不确定因素较多,利益主体目标不同,能够明确分配的风险因素往往不会产生较大的争议,需要双方共享的风险便成为PPP管理成败的关键。本文将前景理论引入PPP共享风险管理的过程中,分析了公私双方均选择积极管理策略的均衡在实际中难以达成的原因,得出了影响演化稳定策略的因素有:公私方积极管理的额外感知成本,对风险发生概率的正确判断,损失分担系数和奖惩力度。为加强PPP项目共享风险的有效管理,本文提出了加强公私双方风险识别和评估能力和风险概率判断的准确性,落实责任分担机制,加强奖惩力度等措施。     

高温高压下NiTi2热力学性质的第一性原理研究

【目的】获得高温高压下NiTi2的热力学性质。【方法】结合准谐德拜模型采用基于密度泛函理论的平面波赝势方法。【结果】对NiTi2高压下的结构进行了几何结构优化,获得了其力学的弹性性能,表明NiTi2在高压下呈弹性各向异性,同时获得了高温高压下NiTi2的热力学性质。【结论】有助于构建 Ni-Ti合金体系的多项物态方程。
     

向量值约化子空间超仿射小波对偶框架的构造

利用Fourier变换和周期化技巧,给出Fourier域上L~2(R~d,C~L)中约化子空间上的超仿射小波对偶框架的一个充分条件,从而将L~2(R~d)中约化子空间上的结果推广到向量值空间L~2(R~d,C~L)的约化子空间上.     

Preparation and electrochemical performance of double perovskite La_2CoMnO_6 nanofibers

Through electrospinning,La_2Co Mn O_6 nanofibers were prepared from a polyvinylpyrrolidone/lanthanum nitrate–cobalt acetate–manganese acetate(PVP/LCM)precursor and were used as electrode materials.The morphologies and structures of the samples were characterized by field-emission scanning electron microscopy(FE-SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and Brunauer-Emmett-Teller(BET)specific surface area analysis.The results show that the prepared La_2Co Mn O_6 nanofibers are stable,one-dimensional structures formed from interconnected La_2Co Mn O_(6 )nanoparticles with a diamond-like crystal structure.The specific surface area of the fibers is 79.407 m~2·g~(-1).Electrochemical performance tests with a three-electrode system reveal the specific capacitance of the La_2Co Mn O_6 nanofibers as 109.7 F·g~(-1) at a current density of 0.5 A·g~(-1).After 1000 charge-discharge cycles at a current density of 1 A·g~(-1),the specific capacitance maintains 90.9%of its initial value,demonstrating a promising performance of the constraint capacitance and good cyclic stability.     

Effects of Fe_2O_3 on the properties of ceramics from steel slag

Ferric oxide is one of the key factors affecting both the microstructure and the properties of CaO-MgO-SiO_2-based ceramics. Research on this effect is significant in the utilization of iron-rich solid wastes in ceramics. Ceramic samples with various Fe_2O_3 contents(0 wt%, 5 wt%, and 10 wt%) were prepared and the corresponding physical properties and microstructure were studied. The results indicated that Fe_2O_3 not only played a fluxing role, but also promoted the formation of crystals. Ceramics with 5 wt% of Fe_2O_3 addition attained the best mechanical properties with a flexural strength of 132.9 MPa. Iron ions were dissolved into diopside, consequently causing phase transformation from diopside and protoenstatite to augite, thereby contributing to the enhancement of its properties. An excess amount of Fe_2O_3 addition(10 wt% or more) resulted in deteriorated properties due to the generation of an excess volume of liquid and the formation of high-porosity structures within ceramics.     

含重置条款的或有可转债路径分解式定价

为了解决或有可转债在长期没有进行债转股的情况下,可能会出现的由于发行方无力支付高额息票而被迫对债券进行赎回的问题,设计了一种包含重置条款的或有可转债。首先,通过对债券存续期内标的股票价格可能发生的路径进行分解,分析了此类条款下债券价值的路径依赖特征;在此基础上,进一步确定了回售边界以及债券价值。通过数值分析得出,本文设计的或有可转债的价值低于相同参数下的不含任何附加条款的或有可转债的价值,并且条款的可用性与目前市场上普遍存在的可赎回或有可转债相比存在一定的优势。敏感度分析结果显示,债券价值与股价年波动率之间呈负相关关系,与修正条款执行日之间呈正相关关系,因而宜根据对未来市场风险的预测来选取适当的条款执行日。     

通道裁剪下的多特征组合目标跟踪算法

针对深层特征存在冗余通道影响跟踪速度和精度以及单一特征难以适应复杂场景的问题,提出了一种通道裁剪下的多特征组合目标跟踪算法。首先,在相关滤波算法的框架上结合传统手工特征和深层特征进行跟踪。其次,通过对比深层特征通道上目标区域和搜索区域的特征均值设计通道裁剪策略,筛选出合适的特征通道。最后,通过隔帧更新的方式更新深度特征,通过平均峰值相关能量更新传统特征滤波模板,最终实现准确跟踪。与10种算法在OTB2013和OTB2015数据集上进行对比实验的结果表明,本文算法在跟踪准确度和成功率方面都取得了更为理想的结果。