青海省黑泉水库混凝土面板坝的工程地质问题与工程处理措施

黑泉混凝土面板坝高 1 2 3.5 0m ,位居中国已建成的混凝土面板坝第四。坝址地形破碎 ,构造发育 ,工程地质条件复杂 ,河床第四纪砂卵砾石层存在不利于坝体稳定和变形的夹层 ,大坝设计采取了一些独具特色的结构措施 ,较好地适应了特殊的地质条件。本文重点分析了大坝的工程地质条件及相应的工程处理措施。     

Spread of jet from an annular slit around an air intake

The results of an experimental investigation of the flow created by a conical jet spreading from a narrow slit around the periphery of a suction intake are described. The reorganization of the jet flow associated with the resulting three-dimensional flow structure is investigated. A flow scheme is proposed.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 187–190, March–April, 1991.     

纸质包装材料中甲醛、乙醛向食品模拟物改性聚苯醚的迁移行为

为了解纸质包装材料中甲醛、乙醛向食品模拟物改性聚苯醚( Tenax)中的迁移行为,建立了一步提取衍生化、超高效液相色谱测定纸质包装材料和Tenax中的甲醛和乙醛的方法。本方法在甲醛和乙醛的测定范围内,线性相关系数R2>0.9999,甲醛检出限为0.03 mg/m2,乙醛检出限为0.04 mg/m2,测定纸样和Tenax的加标回收率为90.1%~108.6%。采用本方法研究不同温度和时间下两种纸质包装材料中甲醛、乙醛向Tenax中的迁移规律。研究表明,甲醛、乙醛迁移行为随时间变化趋势大致相同,均呈现迁移率随迁移时间延长先迅速增大,后又减小达到一个常数;甲醛和乙醛迁移率受温度的影响不同,达到平衡后,甲醛在30℃下迁移率最高,乙醛在70℃和50℃下迁移率高;甲醛和乙醛向Tenax中的迁移率差异较大,达到平衡后,乙醛的迁移率远高于甲醛。     

紫外荧光光谱法测定焦炉气中的痕量总硫

采用紫外荧光光谱法测定焦炉气制取液化天然气的原料气中痕量总硫,考察了样品引入速率、进样量、气体流量、燃烧温度、取样方式和进样方式等条件对分析结果的影响。总硫检出限为15μL·m-3,测定结果与气相色谱法和微库仑法的结果相吻合,测定值的相对标准偏差(n=7)小于10%。     

Green chemistry of polyurethanes: The catalytic <Emphasis Type="Italic">n</Emphasis>-butylaminolysis of ethylene carbonate as a model chain-growth reaction in the formation of nonisocyanate polyurethanes

The kinetic regularities and the mechanism of the catalytic action of 1,5,7-triazabicyclo[4.4.0]dec-5-ene, which is the most active of the known catalysts for the formation of hydroxyurethanes from cyclocarbonates and amines, were studied using the example of the n-butylaminolysis of ethylene carbonate. In contrast with the noncatalytic reaction, which proceeds via two parallel pathways that involve one and two molecules of amine, the catalytic reaction follows a single pathway: the second molecule of amine is replaced by a molecule of the catalyst that accelerates the process in accordance with the mechanism of bifunctional catalysis. Different reaction pathways were studied by quantum chemical calculations based on the density functional method. It was shown that the high activity of 1,5,7-triazabicyclo[4.4.0]dec-5-ene results from the formation of a planar cation-like form of the catalyst. Moreover, the low-energy transition between the cation and the initial 1,5,7-triazabicyclo[4.4.0]dec-5-ene enables the catalyst to simultaneously be a good donor and acceptor of protons. This study presents a new way for finding among bifunctional organic compounds the catalysts that are even more active in the reaction of cyclocarbonates with amines.     

Calculation of three-dimensional weakly expanding flow in jets and channels

The results are given of a calculation of laminar flow in a channel of square section and the motion of a turbulent jet from a cruciform nozzle in an ambient flow. To calculate the secondary flows, the field of the transverse velocity is decomposed into irrotational and solenoidal components. The results of the calculation of the flow in the channel are compared with the calculations of other authors and experimental data. To calculate the flow in the turbulent jet, a one-parameter turbulence model is used, and the influence of the inhomogeneity of the distribution of the longitudinal component of the velocity on the components of the Reynolds stress tensor is taken into account. The results of calculation of the flow in the jet behind a cruciform nozzle are compared with experimental data.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 36–44, July–August, 1984.     

Effect of the chemical grafting of epoxy resin onto organomodified montmorillonite on the structure and heat resistance of an epoxy nanocomposite

It is shown that the noncatalyzed chemical grafting of an epoxy oligomer onto the surface of montmorillonite platelets may proceed via the reaction between the epoxy groups and the hydroxyl groups of the organic modifying agent of the layered aluminosilicate. The effect of grafting on the structure and heat resistance of the cured epoxy nanocomposite is studied. Complete exfoliation of montmorillonite particles into individual platelets is shown to be a necessary but insufficient condition for increasing the glass-transition temperature of the nanocomposite relative to that of the initial matrix. A much higher contribution to the increase in the glass-transition temperature is ensured by grafting of epoxy molecular chains onto the surface of aluminosilicate platelets; i.e., strong covalent matrix-aluminosilicate bonds form in addition to physical bonds, a process that entails development of a thicker three-dimensional network.     

流动肥皂膜气体界面及其在柱状汇聚激波作用下演化的实验研究

在Richtmyer-Meshkov(RM)不稳定性实验研究中,形成两种不同密度流体的初始扰动界面是前提和关健.本文提出了一种流动肥皂膜气体界面生成方法,其工作原理是由细丝构成的导流框从激波管实验段穿过,肥皂液从导流框的上端注入并在重力作用下在导流框中形成流动肥皂膜,膜的两测可以分别充入不同密度的气体从而形成稳定的气体...     

互叶白千层不同部位油细胞分布及显微拉曼光谱研究

为避免复杂的制样提取过程,在天然状态下获得植物样品油细胞中精油的成分,用显微拉曼光谱仪,得到互叶白千层同一植株不同部位的油细胞的分布及油细胞中的主成分。对各部位的显微镜观察发现在软枝干中不存在油细胞或者很少,老叶中的油细胞没有新叶中的多。在老叶油细胞上获得的谱峰中,1 675和726 cm-1为4-萜烯醇的特征峰, 归属为C═C伸缩振动和环的变形振动;1 700和754 cm-1为γ-松油烯的特征峰,归属为C═C伸缩振动和环的变形振动;1 609 cm-1为α-松油烯的特征峰,归属为C═C伸缩振动;1 522,1 156和1 011 cm-1为β-胡萝卜素的的特征峰,分别归属为C═C伸缩振动、C-C伸缩振动和C-C面内摇摆振动。在新叶油细胞上获得的谱峰中,745 cm-1为顺香桧烯水合物的特征峰,归属为环变形振动;1 609 cm-1为α-松油烯的特征峰;1 525,1 160和1 008 cm-1为β-胡萝卜素的的特征峰;老叶与新叶油细胞中的主成分不完全相同,老叶中油细胞精油为γ-松油烯-4-萜烯醇-α-松油烯型,而新叶中油细胞中的精油为顺香桧烯水合物-α-松油烯型。老叶、新叶的共有物为：α-松油烯、β-胡萝卜素。β-胡萝卜素及顺香桧烯水合物为首次在互叶白千层中发现。利用该方法可迅速的确定植株油细胞的主成分,为互叶白千层精油提取提供有益参考。