Effect of cooling rate on solidification structure and linear contraction of a duplex stainless steel

Cooling rate is a key factor that can drastically affect the phase transformation and thermal stress of duplex stainless steels. Therefore, in this research, different sand moulds were used to explore the influence of cooling rate on the solidification of the 2304 duplex stainless steel (DSS). The macro and micro structures of the 2304 DSS were investigated. Small equiaxed grains are obtained in chromite sand mould sample with a lower pouring temperature and a higher cooling rate, whereas coarse columnar and equiaxed grains are found in silica sand and refractory powder mould samples. The size of austenite phase is significantly increased with decreasing cooling rate, while the ferrite phase content ranging from 51.6% to 53.9% does not change obviously. In addition, the linear contraction of the 2304 DSS decreases from 2.34% to 1.09% when the mean cooling rate above 1,173 K increases from 0.99 K·s-1 to 3.66 K·s-1.

Common Fixed Points for Two Mappings with Implicit-linear Contractions on Partially Ordered 2-metric Spaces

In this paper, we introduce a new class U of 3-dimensional real functions, use U and a 2-dimensional real function ? to construct a new implicit-linear contractive condition and obtain some existence theorems of common fixed points for two mappings on partially ordered 2-metric spaces and give a sufficient condition under which there exists a unique common fixed point. The obtained results goodly generalize and improve the corresponding conclusions in references.

THE CONTRACTION LINEAR METRIC PROJECTIONS IN L_p SPACES

In this paper, we study the contraction linearity for metric projection in L p spaces. A geometrical property of a subspace Y of L p is given on which P Y is a contraction projection.

Dissipative Properties of ω-Order Preserving Partial Contraction Mapping in Semigroup of Linear Operator

This paper consists of dissipative properties and results of dissipation on infinitesimal generator of a C0-semigroup of ω-order preserving partial contraction mapping (ω-OCPn) in semigroup of linear operator. The purpose of this paper is to establish some dissipative properties on ω-OCPn which have been obtained in the various theorems (research results) and were proved.

Linear-contract Mechanisms Based on the Risk Preference of an Agent in a Supply Chain

With respect to different risk preference of an agent in a supply chain, linear-contract models are designed according to the principal-agent theory. The study shows that the risk preference of an agent directly correlates with the incentive compensation coefficient of principal, order quantity of principal and production capability level of the agent. The principal should offer an appropriate incentive contract according to the risk preference of the agent, or choose an agent holding a different risk preference to establish the supply chain.

线性化严格收缩的Peaceman-Reachford分裂方法

考虑具有线性约束的三块可分凸优化问题,在改进的严格收缩可分离的凸最小化模型分裂法(MSC-PRSM)的基础上,将原始问题的y-子问题和z-子问题的目标函数分别在y^(k)和z^(k)处进行线性化,并增加一个邻近项,使线性化的MSC-PRSM子问题更容易求解,降低了计算量,从计算时间角度比MSC-PRSM更有优势,并证明了新算法的收敛性.

计及源荷相关度类线性紧缩法的配电网有功无功协同优化

随着分布式电源的高比例渗透,主动配电网的稳定性受到很大影响,因此主动配电网有功-无功协同优化至关重要。对此,提出一种计及源荷相关度类线性紧缩法(Quasi-Linear Contraction,QLC)的配电网有功无功协同优化方法。首先,基于相关性分析方法分析新能源出力以及负荷的相关度,给出源荷相关度概率约束,完善系统优化模型。然后,针对优化模型非凸非线性容易导致局部最优解问题,采用泰勒展开式求解分支电流的上下界并代入节点电压和功率流方程,完成主动配电网模型的类线性紧缩,再采用罚函数方法校正,当得出的解在缩小后的约束范围内时该解为实际最优解,当得出的解在紧缩的约束边界上时,在满足原有约束范围的前提下向外寻优,得到实际最优解。最后,通过Yalmip等仿真计算软件验证所提方法的稳定性、准确性以及有效性。

Leaderless and leader-following consensus of linear multi-agent systems

This paper studies the consensus problems for multi-agent systems with general linear and nonlinear dynamics. The leaderless and leader-following consensus problems are investigated respectively. Contraction theory is employed to gen- erate some sufficient conditions for testing the agents reaching consensus. Under these conditions and certain assumptions, the trajectories of multi-agent systems in directed topology will converge to each other. Finally, two numerical examples are given to illustrate the effectiveness of the proposed results,

STABILITY RESULTS FOR GENERALIZED CONTRACTIVE MAPPINGS

Using a more general contractive definition, this paper continues the study on T stable Ishikawa iteration procedure and generalizes most of the results of Harder and Hicks [1] , Osilike [5] and Rhoades [6-8] . A note on [6][8] is also presented. [WT5,5”HZ]

More Properties of Semi-Linear Uniform Spaces

In this paper we shall generalize the definition given in [1] for Lipschitz condition and contractions for functions on a non-metrizable space, besides we shall give more properties of semi-linear uniform spaces.

带线性记忆的Berger方程时间依赖全局吸引子的存在性

研究了带线性记忆的Berger方程时间依赖全局吸引子的存在性。先用渐近先验估计的方法证明存在时间依赖吸收集,再用收缩函数的方法证明了Berger方程解过程的渐近紧性,从而得到时间依赖全局吸引子的存在性。

乡村振兴背景下茂名市农村土地经营权流转的制约因素及优化路径

为了推动茂名市农村土地经营权流转,盘活农村土地资源,为农村经济建设提供更强的内生动力,推进乡村振兴,本研究以茂名市3个县级市、2个区共计28个典型村庄为样本,运用多元线性回归模型,探究茂名市农村土地经营权流转的制约因素,并针对性地提出优化路径。结果表明,土地细碎程度、租金设定、土地经营权确权、土地情结等因素对茂名市农村土地经营权流转的影响较为显著。因此,在推行土地经营权流转时,当地政府应加强土地整治力度,建设高标准农田;设立合理的定价标准,规范租金浮动价格;建立明确的土地产权制度,加快土地确权颁证工作;转变农民对土地经营权流转的观念。

小湾拱坝模拟实际横缝间距的非线性地震反应分析

本文采用Fenves接触单元模型对小湾拱坝在地震作用下的横缝非线性特性进行了细致深入的研究 ,内容包括有限元网格收敛性、横缝模拟间距和模拟条数收敛性、横缝灌浆强度的影响、不同水位的影响等 ,文章首次采用实际横缝间距和最多达到 2 5条的横缝模拟条数对小湾拱坝进行非线性地震分析 ,揭示出了许多重要工程规律 .Fenves关于“拱坝横缝非线性分析中只模拟 3条横缝就足够了”的研究结论 ,对于应力分析结果尚可成立 ,但要得到符合实际的横缝张开度 ,必须在拱坝关键部位以真实间距模拟横缝 ,并保证一定的模拟条数。此外 ,不同库水位对非线性响应影响显著 。

沥青混凝土低温线收缩系数试验研究

本文结合实际工程,对沥青混凝土进行低温段线收缩系数的试验研究。试验内容主要包括沥青品种、沥青含量、以及不同温度段中沥青混凝土线收缩系数的测试。试验结果表明:沥青品种对沥青混凝土的线收缩系数的影响较大,沥青混凝土在不同温度段的线收缩系数相差很大,而沥青含量(变化范围±0.3%)、升温或降温过程对其的影响较小。

稀土La和Ce对ZL201合金铸造性能的影响

研究了稀土La和Ce的加入对ZL201合金流动性、自由线收缩、合金热裂倾向的影响。试验表明:稀土元素的加入提高了合金的流动性,使其非平衡液相线和固相线温度均略有提高;温度相对降低的过程中,收缩量激增,液固两相温度区间略有缩小,合金线收缩率减小。稀土元素的存在,在一定程度上降低了合金断裂温度并提高了断裂应力。

改良铸造铝硅合金铸造性能的研究

在铸造铝硅合金基础上,添加Cu、Ni、Mn、V和RE等合金元素研制了改良铸造铝硅合金,并检测了该合金的铸造性能。结果表明,改良铸造铝硅合金不但改善了合金的高温力学性能,提高了其服役温度,而且保留了铸造铝硅合金优良的铸造性能。

异质产品供应链定价控制权与零售商横向兼并效应分析

针对一部线性合约与供应商是否具有绝对定价控制权,比较分析零售商横向兼并集中度提高对消费者福利的影响。结果表明,(1)当供应商具有绝对定价控制权时,零售商横向兼并对消费者产生的影响取决于产品替代性程度大小:若替代性程度较高,则将产生有利影响,反之,将产生不利影响;(2)当供应商没有绝对定价控制权时,零售商横向兼并对消费者产生的影响取决于零售商兼并前的相对定价控制权强弱与兼并后的相对定价控制权增幅大小:若零售商在供应链中处于相对弱势地位,且零售商横向兼并使零售商的定价控制权增幅较大,则兼并将对消费者产生有利影响,否则,将对消费者产生不利影响。

基于纳什谈判的合作研发利益分配模型

运用纳什谈判模型,考察了双边道德风险下合作研发的两部线性分成问题,分析了研发效率、协同创造能力和谈判能力对利益分配的影响.研究发现,谈判能力确定双方最终从合作中能分享多少利益,而研发效率和协同创造能力确定最优线性分配比例.考察了协同创造能力和研发效率对研发投入和研发收益的影响,指出协同能力的增强将增大双方的研发投入和合作研发的总收益,而合作一方研发效率的下降将减少自身的研发投入并减少合作研发实现的总收益.最后,提供了一个案例来阐释理论模型在现实中的应用.

一类零售商驱动型供应链契约问题

研究了不同信息结构下零售商驱动型供应链契约问题.对于由1个供应商和1个零售商构成的供应链,考察了线性契约以及2部线性契约.在完全信息及非对称信息两种条件下分别给出了供应商和零售商的最优契约,就批发价格、零售价格及利润进行了比较,并对由供应商、零售商驱动的两种供应链中信息的价值进行了对比研究.理论分析以及数值算例表明,供应商选择2部线性契约优于线性契约,对于完全信息条件,2部线性契约下零售商的期望利润大于线性契约下的期望利润.本文的研究结论对于零售商驱动型供应链的契约设计以及协调问题具有重要意义.

不对称信息下供应链线性激励契约委托代理分析

在由1个供应商和1个零售商组成的供应链中,零售商的促销努力对市场需求有重大影响。但因信息不对称的存在,供应商无法观测到零售商的行为,这样就会产生败德行为,影响供应链的协调。对此,利用委托代理分析框架,研究了供应链中供应商和零售商之间的利益博弈;通过比较在信息对称与信息不对称情况下的线性契约,分析了不同因素对于佣金率、供应商期望收益以及代理成本的影响;最后,考察了新的观测变量对契约设计的影响。