Numerical Analysis of Heat Transport Behavior in the Ferromagnetic Metallic State of La0.80Ca0.20MnO3 Manganites

The lattice contribution to the thermal conductivity (κ_ph) in La_0.80Ca_0.20 MnO₃ manganites is discussed within the Debye-type relaxation rate approximation in terms of the acoustic phonon frequency and relaxation time. The theory is formulated when heat transfer is limited by the scattering of phonons from defects, grain boundaries, charge carriers, and phonons. The lattice thermal conductivity dominates in La–Ca–MnO manganites and is an artifact of strong phonon-impurity and -phonon scattering mechanisms in the ferromagnetic metallic state. The electronic contribution to the thermal conductivity (κ_e) is estimated following the Wiedemann–Franz law. This estimate sets an upper bound on κ_e, and in the vicinity of the Curie temperature (240 K) κ_e is about 1% of total heat transfer of manganites. Another important contribution in the metallic phase should come from spin waves (κ_m). It is noticed that κ_m increases with a T² dependence on the temperature. These channels for heat transfer are algebraically added and κ_tot develops a broad peak at about 55 K, before falling off at lower temperatures. The behavior of the thermal conductivity in manganites is determined by competition among the several operating scattering mechanisms for the heat carriers and a balance between electron, magnon, and phonon contributions. The numerical analysis of heat transfer in the ferromagnetic metallic phase of manganites shows similar results as those revealed from experiments.      

基于CVaR准则具有预算约束和损失约束的报童决策

为了探讨风险态度、现实约束对决策行为的影响, 建立了具有预算约束、损失约束、需求依赖于价格、基于条件风险价值(CVaR) 准则的价格-订单量决策模型, 并给出了模型最优解与约束条件有效阀值求解方法. 研究结果表明, 条件风险价值对损失约束比对预算约束的敏感程度高, 而不同约束的高敏感区域位置不同; 风险规避程度越高, CVaR 对约束值的弹性系数越低; 预算约束值的提高降低了边际贡献率, 风险规避程度越高, 降低幅度越大.

     

The influence of temperature on stacking fault energy in Fe-based alloys

Temperature has great influence on the stacking fault energy (SFE). Both SFE and dr0/ d T for Fe-based alloys containing substitutional or interstitial atoms increase with increasing tempera-ture. Based on the thermodynamic model of SFE, the equation dr0/dT=drcn/dT+drseg/dT+drMG/dT and thoseexpressions for three items involved are established. The calculated dr0/dT is generally consistent with the experimental. The influence of chemical free energy on the temperature dependence of SFE is almost constant, and is obviously stronger than that of magnetic and segregation contributions. The magnetic transition and the segregation of alloying elements at stacking faults cause a decrease in SFE of the alloys when temperature increases; that is, drMG/dT<0 and dyseg/dT<0. Meanwhile, such an influence decreases with increasing temperature, except for the drseg/d 7 of Fe-Mn-Si alloys. With these results, the experimenal phenomena that the SFE of Fe-based alloys is not zero at the thermo-dynamically equilibrated tem     

生物降解混源油混合比例估算方法

研究生物降解混源油的混合比例时的关键是根据研究对象的降解程度，选择既能抗该降解程度又能有效区分烃源岩贡献的生物标志化合物，作为估算原油生物降解前的混合比例的参数，并通过配比实验检验估算结果的可靠程度。在研究渤海PL19—3油田生物降解混源油的混合比例时，选用源自沙河街组三段和东营组下段烃源岩的典型油样，以三芳甾烷／三芳甲藻甾烷作为参数，用估算法计算了PL19—3—4井(最靠近渤中凹陷)生物降解原油混合比例，东营组下段烃源岩的贡献约占30％，该井以南的PLl9—3—2井、PL19—3-8井和PL19—3—5井东营组下段烃源岩的贡献逐步下降，最低约占10％。图4表3参15     

Partially linear model for harmonic contribution determination

Harmonic contribution determination is the premise on which the improvement of power system harmonic management is based. Calculating the harmonic impedance accurately is the key issue in harmonic contribution determination. The fluctuation method is a mature method for calculating the harmonic impedance in engineering applications. However, this method is ineffective when the background harmonic fluctuation is dominant. To make up the deficiency of the fluctuation method, the partial linear regression model for the harmonic impedance calculation is proposed in this paper, and then a two‐stage method is derived for the unbiased estimation of the model. The method proposed in the paper can calculate the harmonic impedance whether or not the background harmonic fluctuation is dominant, and then the harmonic contribution can be determined. The effectiveness of the proposed method is verified by the IEEE14‐bus system simulation and field test. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

一种基于KNMF的非线性故障诊断方法

将核非负矩阵分解方法引入到过程监控中,设计了K2和SPE统计量反映原始数据的能量波动情况,进而检测过程故障的发生。同时提出一种KNMF贡献图计算方法,根据变量和非线性数据的相关性,计算变量贡献值并绘制贡献图,用于故障辨识。在TE模型上的仿真结果验证了KNMF故障检测的良好性能,利用KNMF贡献图可以较好地辨识故障变量。     

丙二烯二氯化膦水解过程的热力学计算及分析

采用相对分子质量法、修正Joback法、Joback法、Lee-Kesler法、Riedel法、Rowlinson-Bondi对应状态法、Benson法估算了丙二烯二氯化瞵水解反应体系相关物质的基本物性参数如常沸点、临界参数和偏心因子,基本热化学性质参数如蒸发潜热、气体热容和液体热容、气体标准摩尔熵、相变熵。利用键能法计算了气体的标准反应热,计算了实际反应条件下的反应热、吉布斯自由能及相关反应的化学平衡常数,并对反应体系的特点进行了分析,估算数据可为理论研究、工程设计与放大及生产提供参考。     

泸州老窖对中国白酒发展的贡献

据考证,泸州老窖今天工艺的雏形始于宋代,泸州老窖拥有我国“老窖”最多,“窖龄”最老的老窖池群,泸州老窖酒以其“醇香浓郁,清冽甘爽,回味悠长,饮后尤香”的风格,驰名中外,成为珍贵的民族遗产,被誉为酒中泰斗,浓香型鼻祖,为了提高中国白酒质量,泸州老窖人将其研究所得科技成果向全国传播、推广,培训酿酒技术人才,为中国白酒香型的发展和质量的提高作不可磨灭的贡献。     

知乎网用户贡献影响因素实证分析

兼具社交性与媒体性的问答型网站知乎网,在近两年内迅速崛起并形成了强大的社会影响力,其核心要素在于成功地激励了知乎网用户进行内容贡献。本文基于TRA、TPB、社会资本理论等学说,以知乎网的实际运行生态为背景进行实证观察,具体分析共同愿景、存在感、知识共享意愿等激励知乎网用户贡献的构成要素。知乎社区中,"用户"的主要角色由信息接收终端转变为信息的生产者或信息的传播枢纽;极少数的意见领袖在生产内容、传播信息方面发挥着不可小觑的影响力。把握18~35岁的主体用户的需求,处理好大V用户和草根用户之间、用户数量和用户质量之间的矛盾,有助于激励知乎网用户进行持续性贡献。