Chemical composition and antioxidant activity of essential oil from Magnolia grandiflora L. seed

The chemical composition and antioxidant activity of Magnolia grandiflora L.seed essential oil were examined.By combining gas chromatography and mass spectrometry (GC-MS),16 types of compounds were identified,including 40.91% oxygen-containing terpene derivatives,19.51% terpenes,13.97% esters,13.05% nitrogenous compounds,and 3.64% acids.Its capability of removing hydroxyl free radical was lower than that of V c,but it was closer to V c with increasing concentration.In cell experiment,all essential oil concentration (6.9,13.8,27.7,55.5,111.0,and 222.0 g/mL) groups increased cell proliferation by 26% or more (26.0%,38.8%,44.8%,40.2%,35.8%,and 30.4%,respectively).In rat experiment,the SD rats group showed an at least 38% rise (38.62%,61.68%,and 62.86%,respectively) in glutathione-peroxisome (GSH-Px)activity,which is more than 24% reduction (29.56%,24.30%,and 36.93%) in malondialdehyde (MDA) content,and no significant difference in SOD activity was found.The results show that the essential oil had strong antioxidant activity,without dose effect within the concentration range.     

前概念对学习力的合成与分解的负面影响及转变策略

物理前概念对学习物理既有积极正面的影响，也有消极负面的影响．正确的前概念可为学习物理垫定一定的基础，促进学生对科学概念的理解和掌握．错误的前概念将是学习物理的绊脚石，在学习中起消极负面影响的作用．文章基于物理前概念对学习力的合成与分解的负面影响的成因，提出了转变前概念对学习力的合成与分解的负面影响的教学策略，以便帮助学生突破学习难点．     

贵阳乌当古生代腕足动物化石壳质成份的初步研究

通过对乌当古生代五组腕足动物化石壳和围岩的光谱半定量及红外光谱测试扫描,发现化石壳的化学成份、矿物成份和围岩关系密切,说明石化过程中,置换、交代作用进行得比较完全,这种研究有明显意义。     

The egg-lipid composition of the ‘living fossil’ reptile tuatara (Sphenodon punctatus)

Summary The lipid composition of two tuatara eggs was examined. The eggs contained triacylglycerol (80%) and phospholipid (12%) as their major lipid fractions. Fatty acid analyses of the individual lipid classes indicated the presence of essential fatty acids, linoleic and arachidonic acids. The quantity of such acids in the egg yolk lipids would suggest they are factors for survival as illustrated in other species.     

有机蒸气在金属氧化物上的催化燃烧(Ⅱ) 甲苯蒸气的催化燃烧

本文研究了甲苯在贱金属氧化物上的催化燃烧，获得了活性顺序。若对同系物苯 催比燃烧时的活性比较，得到了近似直线关系。测定了甲苯在若干催化剂上的反应动 力学参数。并就若干双组分催化剂组成与活性间的关系进行了探索。     

福建沿海丁香鱼的生化成份及能值分析

福建沿海丁香鱼的生化成份及能值分析①王军１苏永全１庄向生２梁军荣１罗宁１（１厦门大学海洋学系亚热带海洋研究所厦门３６１００５２福建省农科院畜牧研究所福州３５０００３）丁香鱼又名海蜒、鱼尧仔，是由多种鱼类的稚、幼鱼组成．因其营养丰富，味道鲜美，除鲜食外...     

语境驱动的仿真模型测试方法论

组合模型的有效性验证是利用模型组合实现仿真系统快速开发的迫切需求,也是组合仿真理论和方法研究的一个重要问题.在分析组合模型抽象层次的基础上讨论了不同层次组合有效性的研究内容,并针对组合模型的行为从测试的角度提出了语境驱动的仿真模型测试方法论,重点讨论了方法论中语境的概念、语境驱动的测试框架生成以及测试框架的嵌入和运行时刻检验等内容,目的是判断仿真模型及其组合行为是否忠实反映了设计信息,实现了行为无错的演化.     

一类二阶线性方程的合成解法

给出一类二阶线性方程的求解公式和解的渐近展开式.     

Characterization of Titanium-Containing Compounds in Gray Iron

Titanium produces different compounds in gray iron. In order to determine their characteristics, a scanning electron microscope, an energy dispersive X-ray spectroscopy, and an optical microscopy were used to analyze the morphology, distribution, and composition of titanium-containing compounds in metal- Iographic specimens and machined surfaces in four gray irons. The results show that the titanium-containing compounds in the gray irons are complex compounds containing V, Nb, Mn, S, and other metals, depending on the concentration of these elements in the iron. The number of titanium-containing compounds increases with increasing Ti content in the gray iron. Most of the titanium-containing compounds are located in the pearlite matrix, with some in the steadite and carbides. The results suggest that titanium-containing compounds reduce tool lifetime.