摘要：The influence of oxygen supply mode on the KIVCET (a Russian acronym for flash?cyclone?oxygen?electric?smelting) process was investigated using numerical simulation. The mass rate ratio (MRR) of central oxygen to lateral oxygen of the central jet distributor (CJD) burner was defined to express the oxygen supply mode, and the KIVCET process with an MRR ranging from 0.09 to 0.39 was simulated. The results show that there are four efficient reaction regions that correspond to four CJD burners. A higher central oxygen flow improves the mixing between particles and oxygen, thus enhancing reactions and shortening the reaction regions. However, a higher dust rate is induced due to the spread of the particle columns. The optimal MRR for a KIVCET furnace with a smelting capacity of 50000 kg/h is suggested to be 0.31. In this case, the chemical reactions associated with the feed are completed with an acceptable dust rate.

摘要：水导激光加工技术中,高质量光束对耦合效率起着关键性的作用。为了解决水-光耦合技术的难题,使水导激光加工技术更好地应用在具有高熔点和高硬脆性的材料的高精密度和低损伤等加工场合,提出自聚焦-球透镜组合聚焦模式和正-负轴棱锥镜组合聚焦模式,并与传统凸透镜聚焦模式进行对比分析。根据三种可适用性聚焦模式,推导相应的ABCD传输矩阵,仿真聚焦模式下的光束特性,并讨论不同聚焦模式下的工业化应用特点。仿真结果表明,正-负轴棱锥镜组合聚焦后的光束束腰半径最小,传统凸透镜聚焦模式聚焦后的光束发散角最小,且三种模式结构不同,都存在各自的优劣性。

摘要：增材制造技术解除了传统制造方法对零件结构的限制,使越来越多复杂结构的“自由制造”成为可能。超材料的出现打破了自然界传统结构在性能上的限制,实现了许多自然结构无法实现的功能。随着增材制造技术的日益成熟,对于高性能、轻量化构件的需求愈来愈强烈,而超材料在具有自然结构所不具备的超常物理性质前提下,进一步实现了超强超轻的机械目标。增材制造的技术特点消除了超材料的制造约束,提高了超材料的潜力,为结构复杂的机械超材料的成型提供了一种有效的方法。零泊松比结构是一种特殊的机械超材料,它优异的性能引起人们的广泛关注。总结了目前国内外增材制造技术成型机械超材料的相关研究进展和激光选区熔化成型具有零泊松比特性的板壳晶格结构的设计难点,并对其发展进行了展望。

摘要：针对航空、常规生产加工等工件的焊接环节,设计了一套新型激光对焊装置。介绍了该装置的基本结构和工作方法,并进行了三维建模及制作。该装置具有操作简单、维护方便等优点,可应用于批量生产中,提高了生产效率。该项目的实施对后续产品的研究、改进及自动化生产具有较高的参考价值。

摘要：贝叶斯动态线性模型(DLM)是一种状态空间模型,在时间序列分析和建模中有大量应用。传统DLM模型的参数确定是由人工分析时间序列的平稳性和季节、趋势、回归特征得到模型参数的,比较依赖专家经验。本文提出用期望最大化(EM)算法从交通流数据中学习出DLM的关键参数,然后用学习出的模型对下一时刻的车流量进行预测。实验表明该模型和方法应用在车流量的预测中取得了较好的效果。相对于自回归求和移动平均(ARIMA)模型和传统季节-趋势-回归组合DLM,所提方法在平均绝对误差和平均相对百分比误差两个指标上均有较大提高。

摘要：Induction heating of steel in continuous casting/rolling process is an important means to reduce energy consumption, decrease cost and improve efficiency, thus becoming an attractive research direction. A mathematical model with Finite Difference Method （FDM） was developed to describe the electromagnetic field and predict the temperature distribution in the steel slab for the whole induction heating process. To validate feasibility of the model, computational results were compared with the ANSYS simulation results. According to the comparing results, the temperature distributions of the slab cast under different technical parameters were investigated, which may provide useful information to optimize the parameters of technology in heating process.

摘要：以穿越厚砂土层的某煤矿主斜井为工程背景,设计了物理模型试验,建立了斜井井壁三维光弹性应力冻结试验方法。实现了考虑斜向倾角作用下穿越厚砂土层斜井井壁应力状态的三维试验模拟,并结合应力冻结后模型横、纵向切片光弹测试得到的全场最大剪应力等值线图对井壁应力随埋深、环向角度变化规律进行了分析。研究结果表明,井壁横向切片内应力水平和应力分布不均匀性均远大于纵向切片,最大剪应力的应力集中区域出现在井壁两帮内缘水平面±25°范围内,斜井井壁顶部最大剪应力大于底部;随斜井井壁埋深增加,纵向应力近似线性增加,但不同环向角度对应的应力增加速度差异较大,从而导致不同埋深位置,井壁内部应力的量值和分布规律均有差异。

摘要：为了研究反共振纤芯壁对空芯光子晶体光纤限制损耗和散射损耗的影响,利用全矢量有限元法对所设计的具有不同纤芯壁和纤芯半径的空芯光子晶体光纤进行仿真,得到了3种纤芯壁在不同纤芯半径时的有效折射率、限制损耗和芯内功率分数随波长变化的曲线。由数值模拟结果可知,纤芯壁采用T=3的环形反共振层和椭圆反共振层设计时,限制损耗降低了约两个数量级,芯内功率分数在通信波段提高了13%。结果表明,这两种设计可以有效降低空芯光子晶体光纤的限制损耗和散射损耗。

摘要：为了消除光纤通信系统中色散,采用各向异性完全匹配层和全矢量有限元方法,进行了理论分析和实验验证,设计了一种基于八角格子晶体的同轴双芯色散补偿光子晶体光纤;得到了该色散补偿光纤的传输特性如基模有效折射率、色散、损耗和非线性系数方面的数据,并分析了光纤波导色散与色散补偿光纤结构参量之间的关系。结果表明,所设计的光纤在200nm的负色散范围内,拥有负色散值(在波长为1.55μm处有最低负色散值-1500 ps/(***)),同时在E+S+C波段有较低的限制损耗(小于3.3dB/km);非线性效应也得到显著抑制。

摘要：Air entrapped in liquid metal during the mold filling process seriously affects the casting quality, thus it is important to track its behavior in the mold cavity. A liquid-gas two-phase flow model is developed to describe the mold filling process and predict the air entrapment defect. The model is based on the combination of SOLA and Level Set Method. The pressure and velocity fields are calculated by SOLA,and the interface movement is simulated by Level Set method as the most common interface tracking method in recent *** order to validate the feasibility of the model,the liquid-gas two-phase simulation results were tested by the broken dam problem and the S-shaped experiment. Comparison between the experiments and simulation results show that Level Set method might be a very promising tool in two-phase flow simulation during the mold filling process.