熔融还原炉内二次燃烧和传热

总结了熔融还原炉内二次燃烧和传热的研究成果，对于转炉采用二次燃烧提高废钢比也有借鉴作用。     

SURFACE TENSION AND BUOYANCY DRIVEN INSTABILITIES IN A LAYER OF LIQUID TIN HEATED FROM BELOW

The linear theory of Pearson (1958) and Nield (1964) is modified here to study liquid tin and include the finite thermal resistances of the bounding layers of boron nitride, copper and air (∼10^-2 torr) in the experiments of Ginde et al. (1989). The magnitude of the ΔT_c across the layer of liquid tin required for the onset of convection depends on the ratios of the thermal conductivities and thicknesses of the supporting layers of boron nitride and copper to those of the tin.

According to our theory surface tension contributes more than buoyancy to the instability observed experimentally. The critical ΔT_c observed required for the onset of convection in the layer of tin, is up to 25% lower than that predicted, which shows the layer is less stable than the theory indicates. Thus the surface of the tin was uncontaminated, or a significantly larger observed critical ΔT_c would be expected.

The boundary condition on the thermal fluctuations at the base of the supporting layer of copper does not appear to be important in these experiments. However, the thermal resistance of the boron nitride would have to be assumed to be unrealistically large to obtain agreement within experimental error with the theory.     

Interfacial tension between coexisting polymer solutions in mixed solvents and its correlation with bulk thermodynamics: phase equilibria (liquid/gas and liquid/liquid) for the system toluene/ethanol/PDMS

Vapor pressures, phase equilibria and interfacial tensions σ were measured for solutions of poly(dimethylsiloxane) (PDMS, M_w[equals]75 kg/mol and M_n[equals]50 kg/mol) in mixed solvents of toluene (TL) and ethanol (EtOH) at 30, 40, 50 and 60 °C. The experimental ternary phase diagrams can be modeled quantitatively from the determined concentration and temperature dependent binary interaction parameters χ_ij if the experimentally inaccessible composition dependence of χ_EtOH/PDMS is adjusted. The relations between σ and the equation of state of the system differ from that applying to single solvents. The exponents as well as the amplitude prefactors of the corresponding scaling laws (e.g. the dependencies of σ on the length of the tie lines or on the hump energy, i.e. on the intrusion into the two phase regime quantified in terms of Gibbs energies) change considerably with temperature. However, this variation can be reduced significantly by normalizing the independent variables. Dividing the length of the tie lines by the length for the corresponding binary subsystem proves more efficient than the distance of these tie lines from the critical point of the ternary system relative to the maximum distance of the binary subsystem. A combined normalization does not improve the situation.     

Complex frequency technique for linear and second harmonic optical properties of metallic surfaces

We describe a complex frequency technique for evaluating the linear and quadratic dielectric responses of metal surfaces, illustrated by application to the surface of jellium. The electric susceptibilities are shorter-range functions of the spatial coordinates at complex frequency, whereas their general behaviour is complicated, long-range and highly oscillatory at real frequency. As a result the linear and the second harmonic electric charges induced by an optical perturbation are then numerically easier to calculate at complex frequency. As the functions which characterize the optical behaviour of the metal surface are analytic in the upper complex frequency half-plane, the dielectric response at real frequency can be deduced by analytic continuation from the results at complex frequency. We illustrate and discuss this approach, which should be useful for studying more realistic models of a surface in which the crystal potential is included, and where a direct calculation of the dielectric response is difficult to obtain at real frequency.     

预应力混凝土箱梁主要裂缝成因和防治措施的探讨

预应力混凝土连续箱梁的裂缝问题一直以来倍受桥梁界专家及技术人员的关注。本文通过对预应力混凝土连续箱梁主要裂缝产生的原因进行了浅析，并提出了相应的防治的措施。     

提速列车作用下上承式钢板梁受迫振动实验研究

本文通过对京哈线下行大清河桥第9孔33.6m上承式钢板梁桥的现场实验结果的分析，以测试孔跨中实测横、竖向振幅为依据，较为详尽地研究了在提速列车作用下桥梁的自身的动力特性及其在提速列车作用下的动力响应，给出了在不同列车运行速度、不同列车编组情况下桥梁横、竖向振幅以及一阶受迫振动频率的变化关系，并对桥梁在列车通过时的桥梁的振动形态、结构的薄弱点及其加固方向进行了初步的探讨。     

速度密度 10m/s住宅

本文通过一次参加日本《新建筑》国际住宅竞赛的经历，就未来高密度城市环境中住宅的生存状态进行了探讨。并试图用以速度来定义密度的方式探索当私密性与公共交往之间出现不可调和的矛盾时一种新的解决之道。     

Studies on nucleation kinetics of InxGa1−xN/GaN heterostructures

Nucleation kinetics during the growth of In_xGa_1−xN on a GaN substrate have been studied. The behavior of nonequilibrium between the In_xGa_1−xN and the GaN substrate has been analyzed, and hence, the expression derived for the stress-induced supercooling/superheating has been numerically evaluated. The maximum amount of stress-induced supercooling is found to be 1.017 K at x=0.12. These values are incorporated in the classical heterogeneous nucleation theory. Using the regular solution model, the interfacial tension between the nucleus and substrate and, hence, the interfacial tension between nucleus and mother phase and thermodynamical potential of the compounds have been calculated. The amount of driving force available for the nucleation has been determined for different compositions and degrees of supercooling. It has been shown that the value of the interaction parameter of InN-GaN plays a dominant role in nucleation and growth kinetics of In_xGa_1−xN on a GaN substrate. These values have been used to evaluate the nucleation parameters. It is shown that the nucleation barrier for the formation of a In_xGa_1−xN nucleus on a GaN substrate is minimum in the range of x=0.12 to x=0.17, and it has been qualitatively proved that good quality In_xGa_1−xN on GaN can be grown only in the range 0<x≤0.2.     

表达式句法分析及求值算法在优化设计中的应用

针对优化设计技术在机械工程领域的使用特点提出了一种应用表达式分析与求值原理以避免对每个优化模型或实例均需编程求解的解决方法,论述了该方法的要求、原理、实现过程及应用程序框架。     

钢纤维混凝土轴拉应力-应变特性的试验研究

本文采用环氧粘接法对4种纤维混凝土材料进行了轴向拉伸试验，成功地获得了材料的应力-应变全曲线。根据其试验曲线是否出现第二峰值，把纤维分为增强与增韧两大类。通过分析表明：不同的纤维形式对混凝土材料的作用机理有较大的差异。在工程应用中，应根据纤维混凝土材料的用途来选择纤维类型。