湿法聚氨酯树脂浆料配方的改进

通过对湿法PU合成革用聚氨酯(PU)树脂浆料配方的改进，降低了浆料的生产成本，浆料的后期加工性能提高，并且PU膜的性能也有所改善。     

残余应力对TiC_p－AIN复合材料的影响

本工作采用热压工艺，以Ｙ＿２Ｏ＿３为烧结添加剂，在１８５０℃下制备ＴｉＣ＿ｐ－ＡＩＮ复合材料。结果表明：复合材料的密度、抗折强度、断裂韧性受第二相ＴｉＣ＿ｐ的影响，通过合理工艺因素选择，可以使复合材料的抗折强度和断裂韧性比基体ＡＩＮ材料分别提高４０％，８０％，达到４３８ＭＰａ，５．５９ＭＰａ·ｍ￣（１／２）。由ＸＲＤ内应力分析和ＴＥＭ显微结构测试结果可知，复合材料性能改善原因在于高弹性用量的ＴｉＣ引入以及ＡＩＮ和ＴｉＣ热膨胀系数不匹配导致的残余内应力。     

A STUDY ON THE SEPARATION OF DIFFUSION AND SURFACE EMISSION COEFFICIENTS IN WOOD

For a more accurate simulation of the moisture sorption process in wood, the precise separation of surface emission and diffusion coefficients is essential. In this paper, a non-linear simplex technique that was developed to obtain the optimum pair of the surface emission coefficient he, and the diffusion coefficient D from a single sorption curve is presented and tested with experimental data. An easy to use computer program was employed to carry out the evaluation. Data analysis showed that the new method resulted in a more statistically accurate calculation of b_c and D than currently existing methods.     

干法/半干法高效脱硫吸附剂的制备研究

干法／半干法脱硫因占地小、投资小、费用低，能达到中等程度的脱硫效率而受到关注。脱硫剂影响脱硫效率的重要因素，Ca(OH)2作为一种优良的脱硫吸附剂，早已受到人们的重视。本文以比表面积为参数评价脱硫剂性能的优劣，研究选择制备高效脱硫剂的工艺方法。     

烟气轮机运行中动平衡破坏的原因分析及维护措施

对引发烟气轮机动平衡破坏的原因进行分析 ,并举例加以说明 ,进而提出了烟气轮机平稳运行的维护措施     

Phase evolution and thermophysical properties of high-entropy RE2(Y0.2Yb0.2Nb0.2Ta0.2Ce0.2)2O7 oxides

Pursuing novel thermal barrier–coating materials with lower thermal conductivity and high-temperature stability can simultaneously improve the working efficiency and service temperature of a gas turbine. In this study, a series of high-entropy RE₂(Y_0.2Yb_0.2Nb_0.2Ta_0.2Ce_0.2)₂O₇ (RE = La, Nd, Sm, Gd, Dy, and Er) oxides were prepared though solid-state reaction. Through tuning the rare-earth cations, an order–disorder transition occurs from certain partially ordered weberite structure (C222₁) to disordered defective fluorite structure (Fm$\overline{3}$m). All the high-entropy RE₂(Y_0.2Yb_0.2Nb_0.2Ta_0.2Ce_0.2)₂O₇ oxides possess low thermal conductivity in the range of 0.91–1.34 W m⁻¹ K⁻¹ at room temperature, which can be attributed to increased lattice anharmonicity and disorder, resulting in additional phonon scattering. Herein, we proved that the incorporation of heterovalent cations at B-sites in high-entropy A₂B₂O₇ crystals is an effective strategy to reduce the thermal conductivity without compromising the decrease of oxygen vacancy. Moreover, the high-entropy RE₂(Y_0.2Yb_0.2Nb_0.2Ta_0.2Ce_0.2)₂O₇ oxides show the relatively higher thermal expansion coefficients of 10.3–10.7 × 10⁻⁶°C⁻¹ and excellent phase stability at elevated temperatures.     

A hybrid recommendation algorithm adapted in e-learning environments

With the rapid development of online learning technology, a huge amount of e-learning materials have been generated which are highly heterogeneous and in various media formats. Besides, e-learning environments are highly dynamic with the ever increasing number of learning resources that are naturally distributed over the network. On the other hand, in the online learning scenario, it is very difficult for users without sufficient background knowledge to choose suitable resources for their learning. In this paper, a hybrid recommender system is proposed to recommend learning items in users’ learning processes. The proposed method consists of two steps: (1) discovering content-related item sets using item-based collaborative filtering (CF), and (2) applying the item sets to sequential pattern mining (SPM) algorithm to filter items according to common learning sequences. The two approaches are combined to recommend potentially useful learning items to guide users in their current learning processes. We also apply the proposed approach to a peer-to-peer learning environment for resource pre-fetching where a central directory of learning items is not available. Experiments are conducted in a centralized and a P2P online learning systems for the evaluation of the proposed method and the results show good performance of it.