电磁搅拌对Fe—C共晶合金石墨片间距与过冷度的影响

Change in structure of oriented growth of Fe-C eutectic alloys with induction stirring is studied. It is found that eutectic structure coarsens obviously with rotated stirring and graphite lamellar spacing increases with increasing speed gradient of solid/liquid (s/l) interface along the radial direction. It is also found that supercooling at the eutectic front is depressed with increasing growth rate and rotation rate. Assuming a lamellar stationary flow parallel to the growth interface within the liquid boundary layer where the solidification takes place, a simple medel is proposed and compared with the experimental results. A good agreement between the experiment and the theoretical model is found     

线性电磁搅拌时金属运动规律的数学模型

依据行波磁场的特点,对自行设计的实验用线性搅拌器磁场力进行了较详细地分析和计算,进而建立了行波磁场作用下液态金属运动规律的二维数学模型,其结果与物理模拟的测试结果吻合较好。     

窦娥形象美感内质浅论

《窦娥冤》塑造了窦俄这一栩栩如生的艺术形象，奏响了一曲感人肺腑的悲歌。从人性美、悲壮美、雄奇美三个方面探讨窦娥形象的美感内质，不仅可以把握窦娥形象的本美，也可以认识其流变美。     

执着而及时的生命价值找寻--浅析电影《寻枪》和《可可西里》的生命价值找寻母题

本文立足于分析电影《寻枪》和《可可西里》的生命价值找寻母题的内涵及在影片中的表现。指出其当下意义主要在于两点：1．满足当代人内心积压的对形而上的追逐欲望。2．刺激当代人思考生命的价值及存在意义。     

吹气搅拌熔池内轴对称循环流速度场的计算——Ⅰ.流场的物理模型及数模边界条件的确定

本文介绍直筒型容器内的熔体,在轴对称浸入喷嘴吹气搅拌下所形成循环流场的基本特征。用统计学方法确定了气液两相区的结构,全浮力模型的观点得到证实。浮力作为基本驱动力的假设和流动参数的高斯分布规律被推荐作为速度场分布数学模化的基础。     

Analysis of cracking phenomena in continuous casting of 1Cr13 stainless steel billets with final electromagnetic stirring

Solidification cracking that occurs during continuous casting of 1Cr13 stainless steel was investigated with and without final electromagnetic stirring (F-EMS). The results show that cracks initiates and propagates along the grain boundaries where the elements of carbon and sulfur are enriched. The final stirrer should be appropriately placed at a location that is 7.5 m away from the meniscus, and the appropriate thickness of the liquid core in the stirring zone is 50 mm. As a stirring current of 250 A is imposed, it can promote columnar-equiaxed transition, decrease the secondary dendrite arm spacing, and reduce the segregation of both carbon and sulfur. F-EMS can effectively decrease the amount of cracks in 1Cr13 stainless steel.     

凝固末端电磁搅拌和轻压下复合技术对大方坯高碳钢偏析和中心缩孔的影响

基于ANSYS软件建立了310mm×360mm断面大方坯连铸过程二维凝固传热数学模型,并采用窄面射钉试验及铸坯表面测温试验对模型的准确性进行了验证.通过模型研究了过热度、拉速和二冷比水量对铸坯中心固相率以及凝固坯壳分布的影响,并结合高碳耐磨球钢BU的高温拉伸试验结果,确定了最佳的拉速以及最优轻压下压下区间要求.通过工业试验对理论模型进行了验证,并分析研究了拉速对采用凝固末端电磁搅拌(F-EMS)以及凝固末端17mm大压下量的轻压下技术生产310mm×360mm断面大方坯高碳耐磨球钢BU铸坯的偏析和中心缩孔的影响.结果表明:采用凝固末端电磁搅拌和轻压下复合技术,通过调整拉速优先满足轻压下压下区间要求,可显著降低中心偏析、V型偏析及中心缩孔,但如果仅达到凝固末端电磁搅拌位置要求时,则铸坯中心质量不会得到明显改善.拉速为0.52m·min-1且轻压下压下区间铸坯中心固相率为0.30~0.75时,偏析和中心缩孔有很大程度的改善,不合理的压下量分配会引起铸坯出现内裂纹以及中心负偏析.     

Effect of enzyme and mechanical stirring on the degradation of polyaspartic acid hydro-gel

As a biodegradable polymer, polyaspartic acid(PASP) hydro-gel has been applied in various fields. Although the degradation mechanism of PASP was well studied, to our knowledge, limited research has been done on the degradation of PASP hydro-gel, whose main chain was crosslinked. This work mainly focused on the effects of enzyme and mechanical stirring on the structure of the PASP hydro-gel during its degradation.The change of the molecular weight and swelling ratio indicates that the simple mechanical stirring caused a break at the crosslink point of the PASP hydro-gel's spatial reticular structure with IR and SEM characterization, but has no significant effect on the degradation of the main chain.Changing the PH value of the degradation system also has little effect on the degradation of the main chain. However, the additions of enzyme both resulted in the break at the crosslink point and the degradation of the main chain, the significant decreases of both the molecular weight and swelling ratio of the PASP hydro-gel were observed.     

干吃面好拌度与爽滑度的分析研究

通过改善酱料的乳化效果、流动特性等,对提升干吃面的好拌度、爽滑度进行了初步研究。采用感官评价、理化检验、安全性实验等方法,初步确定了不同酱料体系选用的乳化剂、胶体的种类和使用量,为今后的产品开发提供了参考依据。     

K型偏心支撑钢框架在循环荷载作用下的力学性能分析

根据偏心支撑钢框架结构在水平荷载作用下耗能梁段发生剪切破坏的特点，在耗能梁段上加了斜加劲肋，设计了5组长度不同的耗能梁段试件，应用分析软件ABAQUS分析了加与不加斜加劲肋的两种情况在循环荷载作用下的滞回性能．结果表明，耗能梁段的长度与Mp／Vp的比值较小时，加斜加劲肋后，框架的弹性位移增大，滞回曲线变得更饱满，耗能能力有所提高．但随着比值的增大，弹性位移减小，耗能能力变差．