废脱硫剂在铁矿烧结中的应用

钢厂煤气脱硫工序排放的废脱硫剂是一种难以利用的有害固体废弃物，含一定量的铁及较高的钙和硫等元素。对废脱硫剂配入铁矿粉中进行了烧结杯的试验研究，结果表明，当废脱硫剂配比超过01%后，随着废脱硫剂配比的升高，烧结矿转鼓强度下降，利用系数下降，烧结烟气中SO2与NOx浓度增加，烧结矿的还原度有所下降，但烧结矿的低温还原粉化性能有所改善。烧结矿的矿相研究发现，废脱硫剂配比偏大时，磁铁矿体积分数增大，铁酸钙体积分数减少，并由针状结构向柱状、板状演变，烧结矿的气孔率上升。主要原因在于其粒度偏粗，含硫高，不利于成矿。当废脱硫剂粒度为-63mm及其配比控制在01%时，烧结矿的产量和质量有所改善，烟气中SO2、NOx较基准试验变化不大。工业试验表明，在烧结混匀矿中配入废脱硫剂配比小于012%时，烧结矿产量和质量没有明显变化，烧结烟气脱硫脱硝效果也没有受到影响。废脱硫剂掺入铁矿中进行烧结是一种资源化利用的有效方法，不仅解决了有害固体废弃物对环境的影响，而且使二次资源得到综合利用。     

车辆自组织网络中新型NP-CSMA随机多址协议研究分析

智能交通的出现使得车辆自组织网络受到越来越多的关注。车辆自组织网络的动态拓扑结构变化非常剧烈,这对网络的吞吐率、传输速率等性能提出了很高的要求。提出1种具有握手机制协议的自适应多通道双时钟NP-CSMA随机多址接入协议。该协议首先区分2种P-CSMA协议,握手机制成功解决了隐藏的终端问题,双时钟机制减少了平均空闲时间,多通道机制增加通道数量和划分用户优先级的同时提高了系统吞吐率,自适应机制能够使系统在高负载下保持稳定吞吐率。还对该协议的传输速率进行了分析,得出该协议的传输速率相对较高的结论。通过平均周期方法推导吞吐率和传输速率的计算公式,仿真结果与理论推导一致。     

基于改进雷达图的配电系统电能质量评估方法

本文针对配电系统电能质量综合评估存在的评估指标权重分配过于主观或客观的问题,提出一种基于改进雷达图法的配电系统电能质量评估方法。该方法利用最小偏差组合权重法计算各评估指标的最优组合权重。并在传统雷达图的基础上对各指标轴间夹角值的确定和特征向量的选取两方面做了进一步的改进。首先采用扇形区域取代原始的三角形区域,并利用最小偏差组合权重法计算各指标轴间夹角值。其次选择新的特征向量构造评估函数对配电系统电能质量进行综合评估。最后通过对某钢铁厂棒材变电站10kV配电系统电能质量进行综合评估,验证了该方法的可行性和合理性。较传统雷达图而言,改进雷达图法解决了传统雷达图法中各指标间信息共用以及评估结果不唯一的问题,使评估结果更加准确合理。     

Effects of temperature on creepage discharge characteristics in oil-impregnated pressboard insulation under combined AC–DC voltage

Due to the complexity of the valve side winding voltage of the converter transformer, the insulation characteristics of the oil-impregnated pressboard (OIP) of the converter transformer are different from those of the traditional AC transformer. The study on effect of temperature on the creeping discharge characteristics of OIP under combined AC–DC voltage is seriously inadequate. Therefore, this paper investigates the characteristics of OIP creepage discharge under combined AC–DC voltage and discusses the influence of temperature on creepage discharge characteristics under different temperatures from 70°C to 110 °C. The experimental results show that the partial discharge inception voltage and flashover voltage decrease with increasing temperature. The times of low amplitude discharge (LAD) decrease and amplitude of LAD increases. Simultaneously, the times of high amplitude discharge (HAD) gradually increase at each stage of creepage discharge with higher temperature. The analysis indicates that the charge carriers easily accumulate and quickly migrate directional movement along the electric field ahead of discharging. The residual charge carriers are more easily dissipated after discharging. The ‘hump’ region of LAD moves to the direction of higher discharge magnitude. The interval time between two continuous discharges is shortened obviously. The concentration of HAD accelerates the development of OIP insulation creepage discharge. The temperature had an accelerating effect on the development of discharge in the OIP under applying voltage.     

板栗壳黄酮结构分析及其对胰脂肪酶活力的抑制作用

在分析板栗壳黄酮结构的基础上，研究其对胰脂肪酶的抑制作用及类型。采用醇提法提取板栗壳中的黄酮，并用AB-8大孔吸附树脂进行纯化，冻干后得到的黄酮含量为（107.50±1.00）mg/g，提取得率为（5.66±0.05）%。利用超高效液相色谱-四极杆/静电场轨道阱质谱联用技术对板栗壳黄酮进行结构分析，鉴定出8 种黄酮类化合物。采用对硝基苯酚法测定胰脂肪酶活力，分别考察板栗壳黄酮对胰脂肪酶的抑制效果及不同反应条件下板栗壳黄酮对胰脂肪酶活性的影响，结果表明，板栗壳黄酮对胰脂肪酶有较好的抑制作用，半抑制浓度（half maximal inhibitory concentration，IC50）为0.074 mg/mL，且使胰脂肪酶最适pH值向碱性偏移。通过Lineweaver-Burk双倒数作图法确定其抑制类型为非竞争性抑制，抑制常数Ki＝53.19 mg/mL。由此可见，板栗壳黄酮是一种效果良好的胰脂肪酶抑制剂。     

Syngas Methanation over Spray‐Granulated Ni/Al2O3 Catalyst in a Laboratory Transport‐Bed Reactor

Syngas methanation in a laboratory transport‐bed reactor has been performed. It was found that the CO conversion over the granular Ni/Al₂O₃ catalyst only slightly increased with the rise of aeration gas velocity for the recycling valve but severely decreased due to decreased gas residence time in the reactor. The effect of increasing the temperature of the recycled catalyst on the CO conversion at atmospheric pressure was also studied. Both the experimental temperature rise along the transport‐bed reactor and the estimated heat balance involving reactions verified the high heat‐transfer efficiency and its technical superiority for syngas methanation.     

Ontology-based approach for the provision of simulation knowledge acquired by Data and Text Mining processes

Numerical simulation techniques such as Finite Element Analyses are essential in today's engineering design practices. However, comprehensive knowledge is required for the setup of reliable simulations to verify strength and further product properties. Due to limited capacities, design-accompanying simulations are performed too rarely by experienced simulation engineers. Therefore, product models are not sufficiently verified or the simulations lead to wrong design decisions, if they are applied by less experienced users. This results in belated redesigns of already detailed product models and to highly cost- and time-intensive iterations in product development.Thus, in order to support less experienced simulation users in setting up reliable Finite Element Analyses, a novel ontology-based approach is presented. The knowledge management tools developed on the basis of this approach allow an automated acquisition and target-oriented provision of necessary simulation knowledge. This knowledge is acquired from existing simulation models and text-based documentations from previous product developments by Text and Data Mining. By offering support to less experienced simulation users, the presented approach may finally lead to a more efficient and extensive application of reliable FEA in product development.     

基于Kӧtter方程的盾构掘进面上被切削土体受力研究

为了计算不同土体性质与不同掘进参数下盾构刮刀与土体之间的作用力以及由此带来的切削扭矩,引入了修正后的Kӧtter方程作为补充方程,求解出开挖面上土体在被动切削至破坏时滑动面上的应力分布,建立了被切削土体受力模型,求解出刮刀刃面与土体之间的正压力p、摩擦力Q与侧向土体间抗剪阻力U,进而推导出刀盘切削扭矩T的计算公式。分析得到特定刀盘上刮刀的p,Q,U值随土体c,φ值增大而增大,通过适当提高刮刀刃面粗糙度来增大摩擦可使土体更易被切至破坏;p,Q,U值随刀盘转速ω增大而减小,p,Q随支护荷载p线性增大且p对于被切削土体受力的影响在砂性土中较大,最终给出特定刀盘掘进至部分种类土体中的切削扭矩值作为工程参考。     

一种改进的最小二乘回归子空间分割方法

最小二乘回归(LSR)算法是一种常见的子空间分割方法，由于LSR具有解析解，因此它的聚类性能较高。然而LSR算法是应用谱聚类方法聚类数据，谱聚类方法初始化聚类中心是随机的，会影响后面的聚类效果。针对这一问题，提出一种基于聚类中心局部密度和距离这2个特点的改进的LSR算法（LSR-DC）。在Extended Yale B数据集上进行实验，结果表明，该算法有较高的聚类精度，具有一定的鲁棒性，优于现有LSR等子空间分割方法。