P-congruence-free Epigroups

Let P denote the equivalence relation on an epigroup in which any of its classes consists precisely of those elements owning the same pseudo-inverse. The purpose of the paper is to characterize epigroups on which any congruence either contains P or its join with P is the identity relation on epigroups. As a special subclass of epigroups, completely 0-simple semigroups having the same property are also described.     

季冻区公路路基砂类土冻胀分类研究

针对季冻区公路路基用土未按照土的分类标准进行冻胀分类的现状,本文对不同含泥量的砂类土在不同含水量、饱和度和密实度状态下进行了一系列闭式冻胀模拟试验。用数理统计方法分别研究了不同含泥量砂类土的冻胀率随含水量的变化规律,并且依据现行公路土的分类标准进行了冻胀分类,为公路勘察、设计、施工和维护提供重要的参考,并为季冻区公路设计规范的编制提供可靠的资料。     

白水峪水电站右岸坝下游边坡岩体的RMR-SMR分类及稳定性评价

本文简要介绍了边坡岩体分类的RMR-SMR系统。结合白水峪边坡, 通过自然历史分析和稳定性计算, 讨论了运用SMR系统进行边坡岩体分类的改进意见。     

澜沧江某电站岩体质量分类中的力学参数选取探讨

本文以澜沧江上游某大型拟建水电站坝区岩体质量分类中的力学参数选取为研究实例, 对岩体质量分类的本质含义, 尤其是如何选取岩体力学参数以及建立它们之间的关系作了探讨。     

Water Redistribution in Irrigated Soil Profiles: Invariant Solutions of the Governing Equation

Exact solutions for a class of nonlinear partial differential equations modelling soil water infiltration and redistribution in irrigation systems are studied. These solutions are invariant under two-parameter symmetry groups obtained by the group classification of the governing equation. A general procedure for constructing invariant solutions is presented in a way convenient for investigating numerous new exact solutions.     

风干含水量W65用作膨胀土判别分类指标的可行性研究

本文针对膨胀土的判别分类指标存在的一些问题,提出一种新指标--风干含水量W65.文中详细研究了它的测试方法,它与膨胀土的物理化学活性,物性指标及自由膨胀率δef等的关系。结果表明,W65能很好反映膨胀土的矿物组成或物理化学活性特征,而δef或WL则更能反映土的粒度组成或分散性特征。最后,在继承δef的判别分类成果基础上,考虑到塑性图的优点,建议采用W65-WL判别分类图。该图能区分膨胀土与典型红粘土,较单一指标判分膨胀土更合理适用。     

岩体可爆性等级判别的遗传程序设计方法

运用遗传程序设计方法，对岩体的可爆性等级判别作了初步探讨，提出相应的计算机智能专家系统，结果表明该方法是可行的。     

The role of elongational viscosity in the mechanism of drag reduction by polymer additives

The role of elongational viscosity in the mechanism of drag reduction by polymer additives is investigated qualitatively by means of direct numerical simulations of a turbulent pipe flow. For the polymer solution, a generalised Newtonian constitutive model is utilised in which the viscosity depends on the second and third invariant of the rate-of-strain tensor via an elongation parameter. This elongation parameter is capable of identifying elongational type of regions within the flow. The simulations show that complementary to stretching of the polymers, also compression must be incorporated to have drag reduction, contrary to many suggestions done in the literature on the mechanism which assume that stretching of the polymers is most important.     

基于加涅学习结果分类理论的化学新教材习题比较研究——以“物质结构基础及化学反应规律”为例

基于加涅的学习结果分类理论,将人教版、鲁科版和苏教版化学必修教材中涉及新课标主题3--“物质结构基础及化学反应规律”的习题从言语信息、智慧技能、认知策略、动作技能、态度维度进行对比分析,结果表明:3者在学习结果的5个维度总体分布趋势相同,智慧技能维度习题占比最大,言语信息维度次之,其余3个维度习题占比均较小;进一步将属于智慧技能维度的教材习题划分为辨别、具体概念、定义概念、规则和高级规则5个由低到高的水平,统计3个版本习题在5个水平中的分布,结果表明:人教版和苏教版具体概念水平的习题占比最大,鲁科版中规则水平习题占比最大,且总体上鲁科版习题智慧技能水平最高,苏教版略高于人教版。并由此获得对教材习题编写和使用的几点启示。     

Identification of Bioactive Compounds of Asparagus officinalis L.: Permutation Test Allows Differentiation among “Triguero” and Hybrid Green Varieties

In this study, we determined the phytochemical profile of the Spanish “triguero” asparagus landrace “verde-morado” (Asparagus officinalis L.), a wild traditional landrace, and the improved “triguero” HT-801, together with two commercial green asparagus varieties. For comparison, we used reverse-phase high-performance liquid chromatography coupled with diode array electrospray time-of-flight mass spectrometry (RP-HPLC-DAD-ESI-TOF/MS) followed by a permutation test applied using a resampling methodology valid under a relaxed set of assumptions, such as i.i.d. errors (not necessarily normal) that are exchangeable under the null hypothesis. As a result, we postulate that “triguero” varieties (the improved HT-801 followed by its parent “verde-morado”) have a significantly different phytochemical profile from that of the other two commercial hybrid green varieties. In particular, we found compounds specific to the “triguero” varieties, such as feruloylhexosylhexose isomers, or isorhamnetin-3-O-glucoside, which was found only in the “triguero” variety HT-801. Although studies relating the phytochemical content of “triguero” asparagus varieties to its health-promoting effects are required, this characteristic phytochemical profile can be used for differentiating and revalorizating these asparagus cultivars.