辽河原油直馏柴油馏分中羧酸含量和结构的探讨

采用醇碱水溶液萃取方法分离出辽河油直馏柴油馏分中的石油羧酸(主要为环烷酸)，采用重量法测出的分离效率不低于90％；用色谱、色谱质谱联用、红外光仪器分析手段对石油羧酸的化学结构进行了较详细的研究，发现了该馏分中石油羧酸在组成和结构方面的一些特征。     

血竭总黄酮对小鼠三叉神经节细胞河豚毒素敏感型钠通道电流的抑制作用

目的:观察血竭总黄酮对小鼠三叉神经节(TG)细胞河豚毒素敏感型(TTX-S)钠通道电流的影响,确定血竭对TG细胞电压门控性钠通道电流产生抑制效应的有效部位.方法:酶解法急性分离昆明种小鼠(1月龄)三叉神经节细胞,应用全细胞膜片钳技术记录TG 细胞TTX-S钠通道电流,观察血竭总黄酮对其影响.结果:在钳制电位为-90 mV时,3种浓度(0.001 %,0.01 %,0.1 %)的血竭总黄酮对锋钠电流的抑制率分别为17.02±5.42 %,33.23±5.12 %,49.30±5.14 %(P值均小于0.05),抑制效应呈典型的浓度依赖性,血竭总黄酮对TG细胞TTX-S锋钠电流的半数抑制浓度(IC50)为0.101 3 %.结论:血竭总黄酮是血竭抑制TG细胞TTX-S钠通道电流的有效部位,该研究为血竭有效成分的提取缩小了研究范围.     

玄武岩织物增强水泥基复合材料拉伸力学性能

利用美特斯(MTS)万能试验机研究了掺入不同体积掺量(0、0.5%、1.0%、1.5%)短切碳纤维、玻璃纤维、钢纤维的2层和3层玄武岩纤维织物增强水泥基复合材料的拉伸力学性能.结果表明:短切碳纤维、玻璃纤维、钢纤维均可明显增加玄武岩纤维织物增强水泥基复合材料的开裂强度,并且存在最优体积掺量;在0~1.5%掺量范围内、2层织物时,开裂强度随着3种短纤维掺量的增加而增加,掺量1.5%时最大;3层织物时,开裂强度随着碳纤维、钢纤维掺量的增加先增加后减小,掺量1.0%时达到最大值,而随着玻璃纤维掺量的增加持续增加,掺量1.5%时最大.短切碳纤维、玻璃纤维不能增加其峰值荷载,而钢纤维则明显提高其峰值荷载,2层织物时最优掺量为1.5%,3层织物时最优掺量为0.5%.     

基于全卷积网络的左心室射血分数自动检测

提出了一种基于全卷积网络(fully convolutional networks, FCN)的左心室射血分数自动估测的方法.利用全卷积网络对心脏磁共振图像中的左心室进行内轮廓分割,计算心脏左心室在一个心动周期中各时间点的容积,提取左心室舒张末期与收缩末期的容积,最后推导出左心室的射血分数.使用700组图片对全卷积网络进行训练以及440组图片进行测试,并将最后计算结果与美国国立卫生研究院和儿童国家医疗中心提供的射血分数(ejection fraction, EF)金标准进行了对比,计算准确率为89.8%,结果处在合理的误差范围内.     

Modelling effects of subgrid-scale mixture fraction variance in LES of a piloted diffusion flame

A posteriori analysis of the statistics of two large-eddy simulation (LES) solutions describing a piloted methane–air (Sandia D) flame is performed on a series of grids with progressively increased resolution reaching about 10.5 million cells. Chemical compositions, density and temperature fields are modelled with a steady flamelet approach and parametrised by the mixture fraction. The difference between the LES solutions arises from a different numerical treatment of the subgrid scale (SGS) mixture fraction variance – an important quantity of interest in non-premixed combustion modelling. In the first case (model I), the variance transport equation is solved directly, while in the second (model II), an equation for the square of the mixture fraction is solved, and the variance is computed from its definition. The comparison of the LES solutions is based on the convergence properties of their statistics with respect to the turbulence resolution length scale. The dependence of the LES statistics is analysed for velocity and the mixture fraction fields, and tested for convergence. For the most part, the statistics converge for the finest grids, but the variance of the mixture fraction shows some residual grid dependence in the high-gradient regions of the jet near field. The SGS variance given by model I exhibits realisability everywhere, whereas in regions of the flame model II is non-realisable, predicting negative variances. Furthermore, the LES statistics of model I exhibit superior convergence behaviour.     

Closed-form solutions of general second order linear recurrences and applications

Two closed-form solutions of a general second order linear recurrence with variable coefficients are established. The first form is combinatorial in nature and is derived through the use of a set which counts the number of elements which are two units apart. The second form is closely related to continued fractions and is derived through the use of continued fraction-like relation. Several applications including a number of verifications of conjectures produced from the Ramanujan Machine are worked out, which illustrate its versatility in this respect.     

A mass‐fraction‐based interface‐capturing method for multi‐component flow

An interface‐capturing method based on mass fraction is developed to solve the Riemann problem in multi‐component compressible flow. Equations of mass fraction with modified form, which is derived from conservative equations of mass, are employed here to capture the interface. By introducing mass fraction into Euler equations system, as well as other conservative coefficients, a quasi‐conservative numerical model is created. Numerical examples show that the mass fraction model performs well not only in multi‐component fluids modeled by simple stiffened gas equation of state (EOS) but also in that modeled by complex Mie–Grüneisen EOS. Moreover, the mass fraction model is applied to Riemann problem with piecewise EOS; the expression of which depends on density. It is found that the mass fraction model can well adapt to the analytic change in piecewise EOS and produce accuracy solutions with fewer unknown quantities, and the model can be easily extended to m‐component fluid mixture by using only m + 4 equations with no additional conditions. Copyright © 2013 John Wiley & Sons, Ltd.     

INVESTIGATION OF A QUASI-STEADY LIQUID CRYSTAL TECHNIQUE FOR FILM COOLING HEAT TRANSFER MEASUREMENTS

A quasi-steady technique to simultaneously measure the local heat transfer coefficient and cooling effectiveness on surfaces involving film cooling situations is investigated. The method employs a composite slab consisting of a very thin laminate layer of low-thermal-conductivity material superposed upon a highly conductive metal substrate. The resulting heat transfer in the thin laminate is described by one-dimensional conduction. A very thin coating of thermochromic liquid crystals sprayed onto the surface of the laminate is used in conjunction with a computer image processing procedure to provide local surface temperature data. This information, combined with the substrate and mainstream gas temperatures, provides highly detailed (90 video pixels/cm²) local convection heat transfer distributions. The method is used to conduct flat-plate film cooling experiments consisting of a single row of discrete holes inclined at 35 to the mainstream flow. The local surface temperature is influenced by the combination of two interacting fluid streams at different temperatures. A numerical analysis was performed to assess the assumptions underlying the data reduction procedure. The experimental uncertainty of 7% in the heat transfer coefficient is comparable to prior studies. Furthermore, the uncertainty of 5% in the film cooling effectiveness, coupled with the negligible lateral conduction errors, indicates the present technique offers a unique capability for accurate measurement of the local film cooling effectiveness.     

Co/SBA-16:对柴油组分有高选择性的费托合成催化剂(英文)

使用浸渍法制备了一系列Co/SBA-16催化剂,并通过氮物理吸附、X射线衍射、氢程序升温还原、氢化学吸附和透射电镜技术对催化剂行了表征。研究表明,随着负载钴含量的增加,金属钴的分散度降低了,这是同Co3O4晶粒增长和比表面积降低相一致的。Co/SBA-16催化剂展示了高的一氧化碳转化率,低的C1选择性和高的C5+选择性,特别对柴油组分有高选择性。     

参数化连分式拟合方法研究及应用

通过倒差商-连分式算法,提出了一种保端点非线性有理参数化拟合算法,通过选取中间点的参数化,利用连分式插值法,得到的拟合函数具有保端点性,规律性和灵活性.实例表明,算法减少了连分式插值迭代次数,避免插值连分式的不存在性,所得到拟合值具有更好的精度,大大提高了计算效率,拟合的误差更具有平稳性,逼近效果更好,并具有较好的预测等方面的应用.