浅谈英语长句的翻译

着重分析了英语长句难译的原因,在进行实例分析的基础上提出了解决问题的步骤、方法,以及对英语学习者的要求。     

重金属稀土元素污染在水生物体内的生物富集

对铅、镉、汞以及镧、铈在鲤鱼体内的生物富集作用进行了室内试验和讨论。结果表明,重金属及稀土元素在鱼体各部位均有较强的富集作用,其中肌肉部分富集能力较弱,内脏富集能力最强;鱼体各部位对重金属及稀土元素的富集作用随时间的增加而增加,在一定的时间后趋于平衡;并且,鱼体中各部位对重金属及稀土元素的生物富集作用存在较大差异。     

全反射X-射线荧光法分析茶叶中的矿质元素

用全反射X -射线荧光法 (TXRF)分析了江西婺绿和宁红茶的矿质元素含量。结果表明 ,所测茶叶中P、S、K、Ca的含量在 2 4 70～ 30 70 0 μg/g ;Mn、Fe在 2 0 6～ 10 70 μg/g ;Ti、Ni、Cu、Zn、Rb、Sr、Ba在 5 5～ 12 2 μg/g ;Pb含量均小于 4 0 μg/g (干基 )。宁红还表现出 ,品质越好 ,P、Ni、Zn含量越高 ,而K、Ca、Mn、Sr、Ba含量则相反。茶汤中K、Rb、Ni的浸出率为 30 5%～ 86 4% ;P、S、Mn、Cu、Zn、Sr为 11 6 %～ 4 2 4% ;Ca为 7 2 %～ 12 6 % ;Fe为 1 1% -2 6 %。茶汤中Ti、Ba、Pb的含量均低于TXRF法的检测限。宁红茶汤还表现出 ,品质越好 ,K、Ca、Mn、Zn、Rb、Sr的浸出率越高。但红茶汤中的K、Zn、Rb、Ni浸出率明显低于绿茶     

Flow analysis of profile extrusion by a modified cross-sectional numerical method

Flow analysis of profile extrusion is essential for design and production of a profile extrusion die. Velocity, pressure, and temperature distribution in an extrusion die are predicted and compared with the experimental results. A two dimensional numerical method is proposed for three dimensional analysis of the flow field within the profile extrusion die by applying a modified cross-sectional numerical method. Since the cross-sectional shape of the die is varied gradually, it is assumed that the pressure is constant within a cross-sectional plane that is perpendicular to the flow direction. With this assumption, the velocity component in the cross-sectional direction is neglected. The exact cross-sectional shape at any position is calculated based on the geometry of standard cross-sections. The momentum and energy equations are solved with proper boundary conditions at a cross-section and then the same calculation is carried out for the next cross-section using the current calculated values. An L-shaped profile extrusion die is produced and employed for experimental investigation using a commercially available polypropylene. Numerical prediction for the varying cross-sectional shape provides better results than the previous studies and is in good agreement with the experimental results.     

油缸未焊接部位的应力强度因子分析

应力强度因子K是断裂力学分析的一个重要内容,本文将油缸底盖与缸体间的未焊接部位视为内含圆筒形裂纹,在裂纹处采用了“1／4”弯曲奇异单元进行三维有限元分析,由裂纹面上的位移外推应力强度因子计算式,计算了油缸受内压和轴向载荷的K值。此研究为三维裂纹体的进一步分析打下了基础,是油缸优化设计关键的一步。其计算方法也可运用于类似结构的压力容器。     

济南近郊侧柏林内降水组成、降水再分配和悬浮颗粒沉积作用初报( 英文)

该文利用离子交换色谱 (HPIC)、ICP -MS和ICP -AES等方法 ,对济南近郊侧柏林内雨水和雪水样品的阳离子组成、阳离子含量、元素组成、元素含量、pH、电导率以及氮氧化物含量进行了测定 .对比分析发现 ,干径流、冠径流和空旷地雨水的电导率、元素组成、元素含量以及离子组成和离子含量呈现明显差异 .比如 ,干径流中钙离子的含量为 150 7mg·L- 1,而空旷地和冠径流的钙离子含量分别为 6 6 4mg·L- 1和 119mg·L- 1.干径流的电导率为 96 2 μs·cm- 1,空旷地的电导率则为 56 0 μs·cm- 1.雪水和雨水的结果比较表明 ,雪水的电导率、pH值、离子含量和元素含量都明显低于雨水 .比如 ,雪水的平均pH值为 4 8,而雨水的平均 pH值为 6 9.针叶叶面冲洗液的分析测定发现 ,有大量悬浮颗粒沉积于叶片表面 .钙、镁、钾、钠 4种阳离子的叶面沉积量达到 35 87kg·hm- 2 ,显示了侧柏林对悬浮颗粒的沉淀池作用     

Similar Boundary Element Method in Elastodynamics

For the boundary element method of elastodynamics, some properties of matrices are discussed in case of similar boundary elements and the similar boundary element method is presented. In a series of similar boundary elements, when the corresponding matrices of a boundary element are obtained, the ones of other boundary elements in the series can be obtained by proportion. Then the coefficient matrix of the last system of linear algebraic equations can be obtained by the method of superposition. Compared with the general boundary element method, the computing speed can be raised by the similar boundary element method given in this paper.     

Boundary Element Methods with Non-overlapping Doma in Decomposition for Elastodynamics

This paper presents the numerical implementation of boundary element method incorporated into a non overlapping domain decomposition method for solving the Navier equations of linear elastodynamics problems by Fourier transformation. Several examples are presented.     

Some Notes on the Variational Principles of Mechanics and Their Applications

This paper discusses the limitations of extension of classical Hamiltonian Principle to continuous systems, then reviews the new developments of operational theory in functional analysis and variational principles in non equilibrium thermodynamics based on field variation. Complementary dual variational principles including adjoined variational methods and generalized Green function method are bases of finite element analysis and boundary element analysis as well. From the point of view of physics, variational principles of macroscopic non equilibrium thermodynamic can be applied to all continuous mechanical systems. However, they have some limitations in application scope and remain to be developed.     

树仔菜嫩梢和叶片中多种元素含量变化的生理分析

分别测定了树仔菜嫩梢和叶片样品中钾、钙、镁、铜、锰、锌、铁、镍、铅、铬、镉等元素的含量,探讨各个元素含量变化的生理规律,以及对植物生长和产品质量的影响。结果表明：钾元素含量的分布规律表现为嫩梢＞嫩叶片＞老叶片,钙、镁、锰、铁、镉元素含量分布规律表现为嫩梢＜嫩叶片＜老叶片,铜、锌、铅、铬、镍元素含量则变化不大。在产品质量安全方面,所测试的铅、镉、铬、镍重金属元素的含量均未超过相关的国家标准或文献报告值。此外,研究发现,树仔菜嫩梢样品中元素含量的测定结果较为稳定,随机抽样可以体现出良好的样品代表性,因此建议将