微型机在室内给水系统中的应用

根据建筑内给水系统水利计算的方法和步骤,介绍了计算程序的编制方法及实现特点,为工程设计提供了有力的依据。     

排水条件下饱和土中氮肥转化与运移模拟

在室内试验的基础上，对施于水层中的氮肥（碳铵：ＮＨ４ＨＣＯ３）在饱和土中的转化与运移过程进行了数值模拟，测定了ＮＨ４＾＋－Ｎ在饱和土中转化和运移的有关参数。结果表明，土壤溶液中ＮＨ４＾＋－Ｎ的计算值与实测值的吻合程度是满意的。     

电机饱和磁场的无内节点亚参有限单元计算

本文首次提出电机饱和磁场的无内节点亚参三角形有限元计算问题,并给出了构造其形状函数的有效方法。同时,结合电机电磁场计算实例,证实了这种新的有限单元能够满足工程计算的精度要求。     

一个Bernstein型插值算子的逼近阶

本文给出了一个以第一类Chebyshev多项式的零点为插值结点组Bernsten型插值算子的逼近阶,并给出了这个算子的饱和阶和饱和类。     

表面弹性能K13项对弱锚定液晶盒指向矢分布的影响

在向列相液晶的Fréedericksz转变(沿面校列状态到垂直排列)过程中,液晶体系的自由能中含有表面弹性能K13项.用数值计算的方法研究了表面弹性能K13项对弱锚定向列液晶盒指向矢分布的影响,且指出饱和点处K13项的存在会影响到外磁场作用下液晶盒的饱和场强值和转变的性质.此外给出了转变类型的判断条件.     

The 3-D non-axisymmetrical Lamb''''s problem in transversely isotropic saturated poroelastic media

The dynamic analysis of saturated poroelastic media is significant in many areas such as seismology, earthquake engineering, soil mechanics and geophysics. In 1956, Biot[1—3] first developed the dynamic equations for saturated poroelastic media. He also discussed systematically the propagation of waves in such two-phase media and further predicted the existence of the slow longitudinal wave. Biots work is consummate while the two formal parameters he introduced are difficult to measure. In t…     

Saturated Heat Capacities of Some Linear and Branched Alkyl-Benzenes Between 288 and 348 K

The saturated heat capacities of benzene and of some linear (toluene, ethylbenzene, propylbenzene, butylbenzene, hexylbenzene, 1-phenylheptane, and 1-phenylhexadecane) and branched (m-xylene, cumene, sec-butylbenzene, tert-butylbenzene, and isobutylbenzene) alkyl-benzenes have been measured. A Micro DSC II from Setaram (France) with batch cells designed in our laboratory, and the scanning or continuous method, have been used to perform the measurements. The estimated uncertainty of the saturated heat capacities was better than 0.3%. In the literature there exists c _sat(T) data for some of the liquids studied. Agreement with our measurements is better than 0.5%. For linear alkyl-benzenes and for each temperature, the variation in the saturated heat capacity with the alkyl length is nearly linear. The selected branched alkyl-benzenes are isomers of the linear alkyl-benzenes studied; accordingly, the influence of molecular structure on the saturated heat capacities has been analyzed.     

Phase behavior and structural properties for the triton X-100/<Emphasis Type="Italic">n</Emphasis>-C<Subscript>n</Subscript>H<Subscript>2n+1</Subscript>COOH/H<Subscript>2</Subscript>O system

In the Triton X-100/n-C_nH_2n+1COOH/H₂O system, n-C_nH_2n+1COOH can be used as a cosurfactant. As its chain length increases, the regions of the microemulsions showing oil-in-water (O/W), water-in-oil (W/O), and bicontinuous structures decrease and at the same time, the region of the lamellar liquid crystal increases. In the O/W region, the distribution coefficient K of n-C_nH_2n+1COOH between Triton X-100 micellar phase and water phase increases with the chain length of saturated unbranched monocarboxylic acid. The relationship between the standard solubilization Gibbs free energy of saturated unbranched monocarboxylic acid and the number of methylene groups in the saturated unbranched monocarboxylic acid is given by the equation: ΔG _m ⁰=−2.364−2.818 n(CH₂) kJ·mol⁻¹ in the Triton X-100 micellar system. In the lamellar liquid crystal region, small-angle X-ray diffraction shows that the thickness of the bilayer d ₀ is independent of the weight ratio of n-C_nH_2n+1COOH to Triton X-100, but the volume of the solvent penetrating from the solvent layer to the amphiphilic bilayer increases with the weight ratio of n-C_nH_2n+1COOH to Triton X-100. Furthermore, the d ₀ value increases with the chain length of saturated unbranched monocarboxylic acid, which will contribute to the formation and stabilization of the lamellar liquid crystal.     

Implementation and Field Testing of Characteristics-Based Intersection Queue Estimation Model

This paper proposes and implements a dynamic queue length estimation model at signalized intersections. Based on the continuum principle, this model describes the formation and dissipation of traffic queues at an intersection and the interactions with the signals. The use of a general speeddensity relationship in the model leads to the development of a general mathematical formulation for intersection queue length studies, which allows the model to adapt to changes in traffic and geometric conditions through parameter updating. Field testing of the model has demonstrated initial success. Experience suggests that use of headway and average speed data in density derivation lead to more stable and accurate results than using other traffic data.     

平面P1波入射下饱和度对深埋圆形衬砌动应力集中因子的影响

准饱和土是天然土体中比较常见的一种形式,与饱和土相同,其内可传播三种体波:剪切波、快压缩波(P1波)和慢压缩波(P2波)。忽略土颗粒的压缩性,考虑孔隙流体的压缩性以及孔隙流体与土骨架之间的粘性耦合作用,采用修正的B iot模型,运用波函数展开法研究了平面P1波入射时,准饱和土体内深埋圆形衬砌的散射问题,通过数值计算模拟并分析了衬砌的动应力集中问题,结果表明:不论入射频率为低频(100Hz)还是高频(500Hz),对于相同的衬砌,当土体为准饱和时,动应力集中因子沿周向分布曲线的形状和数值基本保持不变;但土体为完全饱和时,虽然饱和度发生了微小的变化(比99%只提高了1%),但动应力集中因子的值却大幅度地降低,其沿周向分布曲线的形状也发生了显著的变化,在工程设计中应重视饱和度对圆形衬砌动应力集中因子的影响。