水对室温熔盐[Bpy]BF_4结构与性质的影响

采用分子动力学模拟方法研究了298.15 K、0.1 MPa下摩尔分数为0.05~0.95的水对室温熔盐1-丁基吡啶四氟硼酸([Bpy]BF4)结构与性质的影响.获得了体系的径向分布函数、配位数和空间分布函数等微观结构及其密度、自扩散系数、电导率和粘度等物理化学性质.模拟密度与实验结果符合很好;体系中各组分间的径向分布函数和配位数均随水摩尔分数的增加有规律的变化;获得了各组分之间的三维空间分布情况;随水摩尔分数的增加,阴阳离子之间的相互作用被削弱,同时水与阴离子、阳离子及水分子之间的相互作用逐渐增强,水、阴离子和阳离子的自扩散系数增大,体系粘度降低,电导率升高.研究工作揭示了水对[Bpy]BF4中各组分的存在形式、相互作用及其对体系物理化学及输运性质的影响,为其在冶金与材料制备方面的应用提供理论依据和参考.     

赖氨酸生理功能的研究进展

赖氨酸具有促进机体生长发育、参与能量代谢、促进矿物质吸收和骨骼生长、增强免疫功能、治疗单纯疱疹病毒感染、减轻焦虑等功能,综述与赖氨酸生理功能有关的研究进展表明：赖氨酸不仅可作为营养强化剂促进身体健康,而且可作为某些药物的替代品用于疾病的预防和治疗,以减少药物的副作用。     

经济发展方式转变视域下政协职能发挥探析

人民政协作为我国政治生活中的重要方式,其特有的职能定位赋予了它在我国经济经济发展方式转变中不可或缺的重要作用。在经济发展方式转变过程中,它对于发展的顶层设计、具体过程的监督、行进中资源的整合等发挥着不可替代的作用。基于其现实中所存在的困境,充分发挥政协职能,其着力点在于优化环境、打造平台、完善制度和创新机制。     

基于多层次灰色评价理论的海洋输油管道安全评估方法

针对受多层次、多变量、多种非定量因素影响的海上输油管道系统缺乏有效定量评估手段,建立了输油管道体系的多层次安全评估指标,结合层次分析法,确定了各层指标对应的权重,应用多层次灰色理论,对输油管道体系进行了安全评估,对风险影响程度进行了定量化处理,给出了在役输油管道的可靠性量化结果。对少数据、小样本、信息不完全和经验缺乏的不确定性问题,多层次灰色评估方法具有计算简便、直接、科学和实用的特点,可为在役海上输油管道的可靠性综合评估提供一种量化方法。     

含模糊语言量词的 SQL查询技术研究 *

目前 SQL模糊扩展查询已经研究了带权重的模糊简单查询、复合查询、多表查询、子查询、全关系查询等,在一定程度上解决了查询中的模糊型问题 ,但对于带模糊语言量词的查询研究不多。基于 Zadeh的模糊理论将模糊理论与 SQL系统函数相结合 ,提出了一种解决含模糊语言量词的 SQL查询方法 ,进一步丰富了 SQL模糊查询体系 ,扩展了 SQL模糊查询的应用范围 ,提高了查询能力。     

Solving singular control problems using uniform trigonometrization method

This study investigates the application of a recently developed construct, the uniform trigonometrization method (UTM), to the singular control problems in chemical engineering. The UTM involves minimal modifications to the original problem, thereby generating near-singular control solutions that can be used for conceptual design and serve as an alternate to direct techniques like nested and simultaneous approaches. Eight classical singular control problems with known analytical solutions and three complex singular control problems from chemical engineering domain are solved in this study. The results obtained using the UTM for these problems are found to match well with the literature and are of higher resolution as compared to the results obtained using a direct pseudospectral-based solver. The ability of the UTM to handle complex chemical engineering problems with both singular controls and state path constraints has also been demonstrated in this study.     

路面不平度模拟及其可视化系统的研究

根据路面不平度、自相关函数及功率谱密度三者之问的关系，利用时域AR模型模拟了国标GB7031-86规定的各级路面不平度，并且在Visual C＋＋6．0环境下利用跨平台的虚拟现实集成开发包WTK9．0实现了各级路面不平度的可视化。     

离心铸造大口径球铁管用复合功能型脱硫剂的研制

为使硫量波动的高炉铁液能适应大型离心铸造球铁铸管生产,研制了一种成本较低廉、添加操作简单的复合功能型脱硫剂。其主要组分包括强脱[S]去[O]材料钝化镁粒、碳化钙,增加石墨核心元素Zn和膨胀集渣材料珍珠岩,以及能抑制反球化作用和净化铁液的材料等。采用冲入法进行球化处理,这种脱硫剂覆盖在球化剂和孕育剂上,使用方法简单,效果良好。     

Computer-aided thermodynamic study of solid Co---Pd alloys by Knudsen cell mass spectrometry, and calculation of the phase diagram

F.c.c. solid Co---Pd alloys have been investigated thermodynamically by means of computer-aided Knudsen cell mass spectrometry. Thermodynamic evaluation has been performed by applying the “digital intensity ratio” method. The thermodynamic excess properties can be described algebraically by means of thermodynamically adapted power series with two adjustable parameters, i.e. C₁^G (−20 810 + 9.608T) J mol⁻¹) and C₂^G (−30 720 + 6.78T) J mol⁻¹). At 1470 K, f.c.c. solid Co---Pd alloys are characterized by negative molar excess Gibbs energies G^E, exothermic molar heats of mixing (H^E) and small negative molar excess entropies S^E. At 1470 K, the minimum G^E value is −4600 J mol⁻¹ (61.9 at.% Pd), the minimum H^E value is −9400 J mol⁻¹ (59.5 at.% Pd) and the minimum S^E value is −3.3 J mol⁻¹ K⁻¹ (55.9 at.% Pd). The thermodynamic activities of Co show small positive deviations from the ideal case for the Co-rich alloys (x_Pd < 0.34), and negative deviations from Raoults' law for alloys with higher Pd contents. The Pd activities a_Pd show negative deviations from the ideal case for all compositions. The phase diagram has been computed by means of a generally applicable procedure for the calculation of the equilibrium compositions of coexisting phases. This was achieved using the results of this work, thermodynamic data from earlier mass spectrometric studies on the liquid phase, and literature data for the heat capacities and enthalpies of Co and Pd.     

A pseudo-spectral scheme for the approximate solution of a time-fractional diffusion equation

We consider an initial-boundary-value problem for a time-fractional diffusion equation with initial condition u₀(x) and homogeneous Dirichlet boundary conditions in a bounded interval [0, L]. We study a semidiscrete approximation scheme based on the pseudo-spectral method on Chebyshev–Gauss–Lobatto nodes. In order to preserve the high accuracy of the spectral approximation we use an approach based on the evaluation of the Mittag-Leffler function on matrix arguments for the integration along the time variable. Some examples are presented and numerical experiments illustrate the effectiveness of the proposed approach.