Pressure drop in a packed bed with sintered ore particles as applied to sinter coolers with a novel vertically arranged design for waste heat recovery

The pressure drop over a packed bed with sintered ore particles was studied experimentally. The sintered ore particles were characterized to determine their equivalent particle diameter, bed voidage, and sphericity. The pressure drop experiments were performed on unsorted and sieved particles with various size distributions for a superficial velocity up to 2.4 m/s, covering flow regimes from laminar to turbulent. It was shown that the Ergun equation underestimates the pressure drop for such highly irregular-shaped particles by about 40%. The measured modified friction factor was well correlated to a scaled Ergun equation, which was verified to be valid for the modified particle Reynolds number up to 12 000 toward design and optimization of vertically arranged sinter coolers for waste heat recovery.     

大中小学德育课程合理性建构的研究现状与对策分析——兼谈“习惯课“的重要性

使用高二的哲学试题测验大三学生引发出许多困惑,这与德育课程研究存在“四多四少”问题有直接关系。适应市场经济体制,我国德育课程从三个层面进行了改革探索,目的是让学生养成良好的道德行为习惯。“习惯课”是一种较好的德育课实践模式。     

抗日战争时期的国民党正面战场

抗日战争时期,中国共产党在全面抗战路线思想的指导下,领导中国人民在敌后开辟一系列抗日根据地,对打败日本侵略者起了决定性作用。国民党政府作为正面战场也为抗战的胜利作出了一定的贡献。     

迎接学习社会的到来

1996年,以雅克·德洛尔任主席的“国际21世纪教育委员会”向联合国教科文组织提交了一份报告(简称“德洛尔报告”),这份报告在我国出版时曾翻译为《教育——财富蕴藏其中》。对照英文名称可以发现,该报告的题目并非“Education”(教育),而是“Learning”(学习)。 学习,财富蕴藏其中,可以理解为,知识经济时代是教育的时代,知识经济将与学习社会伴生伴长。由此看来,21世纪的教育必须围绕着基奉学习能力重新设计和     

光电催化降解有机废水的研究进展

有机废水的光电催化降解是集光、电、化学氧化于一体的处理有机废水的新方法、新工艺。它具有高能电子、紫外线和臭氧等多种综合因素的物理化学效应;特别对难以降解的废水有机物具有强大的催化功效,并且有无毒、无二次污染的特点;是21世纪研究有机废水降解的发展方向之一,具有广阔的前景。     

论毛泽东在抗战时期的民主政治思想

本文从民主政治在抗战中的地住和作用，我们所争取的民主政治的性质、重要内容以及实现民主政治的途径和方法等方面对毛泽东在抗战时期的民主政治思想进行了全面的阐述。     

医学人文教育的危机与重塑

近年来,我国医学人文教育虽有了一定程度的发展,但从总体上看还十分薄弱,存在着政策内涵模糊、课程规划失范、研究碎片化等突出问题,发展水平与其应承担的责任之间相距甚远。破解医学人文教育危机,需改革医学人文教育体系,建立一个包括制度支持、课程规划、教学实践与医疗慈善在内的整体系统,以促进医学技术与医学人文的深度融合,培育医学生高尚的医德修养和丰富的人文情怀。     

论中国农村土地产权制度

农村土地是农业生产、农村发展和农民生活的物质资料基础。农村土地权利体系的科学构建对于解决相关问题具有基础性意义。遵循正确的指导原则，明确农村土地权利的人格化代表，合理界定农地产权制度的基本内容，规范农地资源的流转机制，建立解决农地纠纷的法律机制是我们改革和完善农地产权制度的基本思路。     

Large eddy simulation of the gas-particle turbulent wake flow

To find out the detailed characteristics of the coherent structures and associated particle dispersion in free shear flow, large eddy simulation method was adopted to investigate a two-dimensional particle-laden wake flow. The well-known Sub-grid Scale mode introduced by Smagorinsky was employed to simulate the gas flow field and Lagrangian approach was used to trace the particles. The results showed that the typical large-scale vortex structures exhibit a stable counter rotating arrangement of opposite sign, and alternately form from the near wall region, shed and move towards the downstream positions of the wake with the development of the flow. For particle dispersion, the Stokes number of particles is a key parameter. At the Stokes numbers of 1.4 and 3.8 the particles concentrate highly in the outer boundary regions. While the particles congregate densely in the vortex core regions at the Stokes number of 0.15, and the particles at Stokes number of 15 assemble in the vortex braid regions and the rib regions between the adjoining vortex structures.     

Preparation of Vitamin E Intermediate from an Inexpensive Substrate by Selective Oxidation of Pseudocumene in HCOOH–H_2O_2 System

In this paper, 2,3,5-trimethyl-1,4-benzoquinone(TMBQ) was synthesized through the direct oxidation of1,2,4-trimethylbenzene(pseudocumene, TMB) in the HCOOH–H_2O_2 system. The influence ofthree active species was studied, including performic acid(PFA) generated in formic acid, peracetic acid(PAA) generated in acetic acid, and trifluoroperacetic(TFPA) acid generated in trifluoroacetic acid. The effects ofsulfuric acid and sodium formate addition were investigated, the overoxidation ofTMB was discussed, and the main reason for the decreasing selectivity was revealed. The oxidation ofTMB can be controlled and improved through adjusting the reaction temperature, mole ratio ofoxidant to substrate, and reactant concentration. The TMBQ yield of28% was achieved with a TMB concentration of0.2 mol/L, H_2O_2/TMB mole ratio of6:1, and reaction temperature 37 °C. The selectivity of72% was obtained with a TMB concentration of0.2 mol/L, H_2O_2/TMB mole ratio of5:1, and reaction temperature of27 °C. The reaction mechanisms were proposed and discussed based on the gas chromatography–flame ionization detection(GC–FID) and gas chromatography–mass spectrometer(GC–MS) results.