A strategy for defects healing in 3D printed ceramic compact via cold isostatic pressing: Sintering kinetic window and microstructure evolution

In this study, we developed a unique defect healing method for 3D printed ceramic compact via cold isostatic pressing (CIP) after debinding, and typical features of interlayer interface defects of 3D-printed zirconia compact were characterized and found to be reduced significantly. The characteristic sintering kinetics window and microstructure evolution of the healed sintered bodies were systematically investigated, which was found to be quite different from conventional shaping methods. The three sintering stages are probed by their feature microstructure details such as the mechanically flattening surface at the early sintering stage, the heterogeneous microstructure and high porosity in the interlayer interface region at the middle stage, and the slightly ripple-like structural features combined with the healed interlayer defects at the final stage. The evolution of the pore structure of the healed 3D printed bodies were traced and the mechanical properties such as the Young's modulus, hardness, and fracture toughness were measured to understand the significance of the heal effect.     

Preparation and Applications of Soybean Residue CNF Films

In this study, soybean residues were treated with HCl and soybean residue cellulose was extracted, which was used to prepare cellulose nanofiber (CNF) using the high-pressure homogenization method. The maximum yield of CNF, the reaction temperature, reaction time, and HCl concentration were optimized. The optimum HCl concentration for acid treatment was 6%, the reaction time was 60 min, the reaction temperature was 80℃, and the maximum yield of soybean residue cellulose was 78.8%. The different CNF films were then prepared; the color, mechanical property, and light transmittance of the CNF films were studied. Compared to the properties of the CNF film prepared with the soybean residue cellulose by high-pressure homogenization 15 times (HGT-15 film), the mechanical properties of the CNF film with soybean residue cellulose by decolorizing treatment decreased, but the light transmittance increased. The film prepared by adding HGT-15 CNF to whey protein was investigated for its mechanical property, light transmittance, and solubility. Unlike the pure whey protein film, addition of 2.0% CNF to the whey protein enhanced the mechanical property and water vapor transmission rate (WVT) of the film. With the increase in CNF content, the solubility of the whey protein film decreased, and then stabilized.     

应用拓扑指数计算润滑油馏分正构烷烃熔点

在分子图的距离矩阵和邻接矩阵基础上对润滑油馏分正构烷烃分子的拓扑指数进行了计算，并以Balaban中心指数的计算为例进行说明。求得C20～C44正构烷烃的B指数和J指数，并以C20～C44正构烷烃的熔点与其相关的拓扑指数进行多元线性拟合为例说明其应用。     

ZF-内冷绝热轴径向氨合成塔内件应用总结

介绍了Φ1000mmZF-内冷绝热轴径向氨合成塔内件结构及特点、催化剂的装填、升温还原及投入使用后的情况。氨合成塔内件及催化剂更换后,系统运行稳定,塔阻力由0.8MPa(双塔并联)下降至0.5MPa(单塔),系统压力由28.4MPa降至25.9MPa,同时氨产量提高了10t/d。     

超级电容器电解质研究进展

电解质作为超级电容器的重要组成部分,对器件性能起着关键性作用。本文对近些年来超级电容器各种电解质,包括水系、有机液体、离子液体、固态/准固态聚合物电解质和氧化还原体系电解质的特点和最新研究成果进行了描述;重点介绍了固态/准固态聚合物电解质的分类及其性能研究概况。提出了发展电位窗口宽、离子电导率高、电化学性能稳定的离子液体和机械强度等综合性能优良的凝胶聚合物电解质是将来超级电容器电解质发展领域的趋势,最后对超级电容器电解质的发展前景进行了展望。     

电网频率特性及负荷反馈df／dt的实测分析

根据电网频率运行的要求，对表征电网频率特性的频率衰减时间常数Ｔｆ、静态负荷频率调节系数ＫＬ进行了试验研究和理论分析计算。对系统功率缺额频率滑差ｄｆ／ｄｔ和负荷频率反馈ｄｆ／ｄｔ进行了识别，为ＳＺＨ－２型数字周波继电器的ｄｆ／ｄｔ整定和低电压闭锁整定提供了可靠的参考。     

无风撑钢管混凝土中承拱桥非线性试验分析

通过大比例尺模型桥荷载试验结果与非线性计算结果比较，提出拱肋截面为三角形空间桁架结构的中、下承式钢管混凝土拱桥，可不考虑非线性问题。     

海洋平台结构环境激励的实验模态分析

介绍了对位于渤海湾的“埕岛二号”中心生活平台所进行的现场测试实验,该平台为直立式导管架钢结构平台。此次现场实验是在波浪力、风等环境载荷激励下测试结构动力响应的。利用频域的模态识别法峰值法(PP)和时域中的自然激励法(NExT)结合特征系统实现算法(ERA)分别对海洋平台结构现场测试的动力响应数据进行模态参数识别;利用ANSYS建立了该平台结构的三维有限元模型,并进行结构的模态分析。海洋平台结构的理论和实验模态分析结果吻合较好,分析结果表明该类模态参数识别方法能够为结构损伤诊断提供基准模型,可以运用于实际结构的健康监测以及维护维修。     

Assessing emergency regulation technology in the Middle Route of the South-to-North Water Diversion Project,China

Abstract

The Middle Route of the South-to-North Water Diversion Project is important for China. Any sudden water pollution accident along the route would threaten normal water supply. We studied four technologies (hydrodynamic and water quality simulation, source identification, emergency regulation, and evaluation of emergency measures) and developed and implemented a decision support system that provides technical support in managing pollution accidents. The achievements, which include four technologies and a system, have practical significance for emergency management in the Middle Route as they can help deal with accidents and policy formulation, and can be applied to other water transfer projects.     

梯级泵站输水系统日优化调度及经济运行研究

南水北调来水调入密云水库调蓄工程是北京南水北调配套工程的重要内容,前半段从团城湖通过6级泵站提升输水至怀柔水库。为实现工程高效经济运行,基于分时电价规则,建立大系统分解协调模型求解该工程日优化调度及经济运行问题。将大系统分解成3个子系统,先采用动态规划法实现各子系统的最优化,然后根据大系统的总体目标,依据各子系统之间的关联,实现大系统的全局优化。结果表明,模型实用性强,优化调度运行方案中低电价时段所分配流量较大,对于实现工程高效经济运行具有指导意义。