壳聚糖交联酸改性粉煤灰的制备及对Mn~(2+)的吸附性能研究

以壳聚糖和酸改性粉煤灰为原料,制备壳聚糖交联酸改性粉煤灰吸附剂.利用SEM、XRD、FTIR对其结构进行表征,考察其制备及吸附条件对Mn2+去除率的影响.结果表明:制备时,当壳聚糖与酸改性粉煤灰的质量比为1∶10,交联剂用量为2 mL/g;吸附时,废水pH为9,吸附时间为90 min,吸附剂用量为10 g/L时,Mn2+去除率为98.7%.     

Effect of crystallization temperature and propylene sequence length on the crystalline structure of propylene-ethylene random copolymers

Crystallization behavior and resultant crystalline structure of a series of temperature-rising elution-fractionated specimen of a Ziegler-Natta catalyst-synthesized propylene-ethylene random copolymer were studied by DSC, WAXD and AFM. The experimental results indicate that both crystallization temperature and propylene sequence length exhibit great influence on the crystallization behavior and crystalline structure of the copolymer. It was found that the ethylene co-monomers acting as point defects inserted into the polypropylene chains play an important role in the formation of y-iPP. As the co-monomer content increases, the crystallizable sequence length of iPP decreases, which produces an appropriate condition for its y crystallization. At the same time, the existence of chain defects leads to a lower crystallinity of the copolymer and imperfection of the resultant crystals. For each individual sample with certain propylene sequence length or ethylene content, the increment of y-iPP crystal content with increasing crystallization temperature demonstrates that higher crystallization temperature is in favor of the y-iPP crystallization. Pure y-iPP crystals have been got in samples with propylene sequence length lower than 21 under suitable crystallization conditions.     

屈曲约束支撑铰接钢框架结构体系抗震性能

基于利于结构安装和抗震修复以及屈曲约束支撑的特点,采用梁柱铰接钢框架承受竖向荷载、屈曲约束支撑抵抗水平荷载的结构体系,并推导了这种结构体系的楼层弹性和弹塑性抗侧刚度.采用双线性模型模拟屈曲约束支撑的滞回性能,采用时程分析方法分析了屈曲约束支撑铰接钢框架结构体系的抗震性能、弹性及弹塑性地震反应特征.结果表明:多遇地震下,结构楼层位移反应基本呈线性关系,层间位移角分布比较均匀;罕遇地震下会出现薄弱层现象,但各层支撑都会屈服耗能.除底层以外,楼层剪力主要由支撑承担,而底层框架柱承担的楼层剪力比例会增大;框架梁和柱在各级地震下都处于弹性状态;屈曲约束支撑铰接钢框架结构体系具有较好的抗震性能.     

Structure Optimization of Air Filter Based on Parametric Sensitivity

As the supporting supplier of the main engine plant, the general air filter manufacturers have insufficient technical reserves. The structural optimization of air filter is often based on the bench experiment, which has high implementation cost and poor performance. In view of this, taking computational fluid dynamics(CFD) as the basic technical means, an optimization design method based on parametric sensitivity combined with equidistant search was proposed. Specifically, the sensitivity of local structure parameters to pressure loss was analyzed by taking local structure of air filter as the object. According to the sensitivity, the method of equidistant search was used to optimize the parameters in order, so as to achieve the goal of overall optimization. After optimization, the pressure loss decreased by 45.13% and the effect was remarkable.     

液相色谱法测定洋甘菊中芹菜苷质量浓度研究

探讨了用高效液相色谱仪检测洋甘菊中芹菜苷质量浓度的方法,并测定了样品中芹菜苷的质量浓度.采用依利特Sinochrom ODS-BP柱(4.6mm×250 mm,5μm),流动相为甲醇-1％乙酸(体积比为60∶40),流速1.0 mL/min,柱温25℃,检测波长333 nm,作为测定样品中芹菜苷质量浓度的条件.结果表明,芹菜苷在0.999 9～99.99 μg/mL质量浓度线性范围内线性关系良好,R2=0.999 9,平均回收率为1.04％,RSD=1.87％,测得芹菜苷在洋甘菊中的质量浓度为83.205 mg/L.此方法快速、简便、准确,可用于洋甘菊中芹菜苷的HPLC测定.     

基于相关性分析的下肢假肢步行模式预识别方法

为了减小假肢执行器延迟以及判断程序延迟对动力型假肢协调控制带来的影响,采用步行模式预识别的方法,提前控制动力型下肢假肢的运动,以达到最佳的协调控制效果.利用假肢接受腔装配的陀螺仪传感器、加速度传感器以及安装在假肢足底的压力传感器来进行数据采集,通过分析传感器采集数据与模版数据之间的相关性信息来实现步行模式的预识别.实验结果表明利用分析多传感器数据的相关性预识别步行模式的方法是有效的,可使假肢及时调节、及时动作,增强了假肢的智能性,该技术对智能假肢的发展具有重要的实用价值.     

有限生成模自同态环的一种刻画

定义了矩阵环的零化子,对有限生成模的自同态环进行了刻画.证明了有限生成左R-模的自同态环是环R上矩阵环的一个子环的同态像,并利用此结果给出了代数学中一些经典结论的新的证明.     

论文学教育的现状与价值实现

文学教育作为公共课目前已走入教育的边缘地带,学生对文学的兴趣不高,教学仍然止步于文本解读,文学对人生的深广关照并未凸显。文学教育应帮助学生在“我的”经典的阅读中满足审美需要,获得洞见人生的力量,涵养自由之精神,构架健全之人格,使文学教育真正成为“人”的教育。     

喷油提前角对双燃料柴油机燃烧和排放的影响

为研究喷油提前角对双燃料发动机燃烧和排放特性的影响,以4190ZLC-2型船用中速柴油机为研究对象,运用AVL_FIRE软件构建柴油-甲醇双燃料燃烧室模型。通过仿真实验的方法,研究当甲醇掺混比为20%,喷油提前角分别为 16.6°、18.6°、20.6°、22.6°时,对柴油机燃烧、排放、动力特性的影响。研究结果表明:随着喷油提前角的逐渐增大,缸内混合气质量得到改善,从而优化混合燃料在缸内燃烧的质量,同时还可观察到放热率曲线逐渐前移且峰值增加。分析数据可知,在甲醇掺混比为20%,喷油提前角20.6°时,NO排放较原机排放增加29.83%,Soot排放量降低30.5%,CO排放量降低5.6%,指示功率增为58.75 kW。     

不同施工方法下浅埋偏压小净距隧道的围岩稳定性

采用MIDAS/NX有限元模拟软件,模拟了浅埋偏压小净距隧道的开挖施工过程,研究了不同施工方法下浅埋偏压小净距隧道的洞周围岩位移、仰拱位移、地表沉降及岩质边坡位移的变化规律。结果表明:开挖方法对围岩位移、地表沉降、边坡位移的影响较大;在岩质边坡的存在下,左洞与右洞的位移有较大的差别;中隔壁法对位移的控制最好。在岩质边坡下开挖隧道,边坡各个方向的位移都较大,因此,在隧道开挖过程中应充分做好边坡的防护工作。