膜结构设计与施工

对两个索膜工程的设计与施工过程进行了论述,并对两工程在施工过程及预应力的施加方法上的差别进行了横向比较:对于帐篷膜结构而言,设计对结构最终成功与否所起的作用更大,在该结构的设计中膜与柱相连节点的顶圈与环销相分离的做法是创新之处;对于活动铰支座形式的膜结构,施工所起的作用更大,施工方法是否正确、预应力施加与调整,对结构的最终成型有至关重要的影响。     

Influence of conical strip inserts in heat transfer enhancement under transition flow

ABSTRACT

The performance of the concentric tube heat exchangers can be increased due to the swirl flow generation caused by the inserts which exchange heat in an effective manner. Many researchers have studied the thermal behaviour of different types of inserts, such as twisted tape and wire coil, with different geometries. This work dealt with the heat transfer and friction factor behaviour of newly fabricated staggered and non-staggered conical strip insets. The conical strip insert produces much swirl flow corresponding to the twist ratios (Y?=?2, 3 and 5). The experimental results are in good agreement with the correlations developed for Nusselt number and friction factor with the help of regression analysis.     

折边锥体封头的一种精确展开法

对折边锥体封头展开成扇环的解析法作了探讨，总结出折边锥体封头展开的一组精确计算公式。     

伞喷燃烧系统的应用研究

本文绘出了伞喷燃烧方式在１３５型试验机上进行的试验研究，性能参数表明该燃烧方式具有热预混合燃烧的特点，且改善了经济性、工作粗暴性和排入指标。     

Discontinuity effects at cone-cone axisymmetric shell junctions

In this paper, the problem of a conical shell axisymmetrically intersecting another conical shell, such that the vertices of the cones lie on opposite sides of the plane of intersection, is considered, and associated discontinuity effects quantified for arbitrary loading and geometric parameters of the intersecting cones. The ensuing very practical closed-form results are based on the one-term asymptotic-series solution for the axisymmetric bending of a non-shallow conical shell, and are intended for use in the quick evaluation of stresses and deformations in double-cone pressure vessels, as well as liquid-retaining vessels with intersecting conical portions. As an example of the application of the developed formulation, the stress distribution in a large liquid-filled elevated rhombic tank is evaluated. The stresses obtained on the basis of the closed-form analytical approach developed in the paper are shown to be in good agreement with those obtained from a finite-element analysis, confirming the reliability of the presented formulation.     

A self-calibrating piezoelectric transducer with integral sensor for in situ energy calibration of acoustic emission

Piezoelectric transducers are used as both transmitters and sensors in acoustic emission (AE) testing applications. However, the transducer outputs are significantly affected by the coupling between the transducer and the structure. This means that the coupling must be very carefully controlled or assessed if reliable AE calibration sources are to be generated, and be considered in the AE system calibration if reliable AE measurements are to be made. The paper shows that by integrating a piezoelectric AE sensor to the backing of a conical piezoelectric transducer acting as the transmitter, a self-calibrating AE energy point source can be obtained. There is a negative linear relationship between the AE signal energy from the backing sensor and the coupling efficiency for a constant electrical input to the transmitter over the frequency range of interest in AE measurements (100 kHz to around 1 MHz). This should enable the strength of the simulated AE point source to be determined using the AE measurement from the backing sensor, and hence to facilitate in situ energy calibration of AEs in structures.     

A Draft-Tube Conical Spouted Bed for Drying Fine Particles

A study has been conducted on the performance of a draft tube conical spouted bed for drying fine particles. Batch operation has been performed with nonporous, porous, and open-sided draft tubes in order to ascertain the optimum configuration of this internal device. The nonporous draft tube requires the lowest minimum spouting velocity. Nevertheless, the solid circulation rate and the drying efficiency of the open-sided draft tube are superior to any other spouted bed configuration. Moreover, it allows for reducing the height of the fountain and, consequently, the height of the drying equipment.     

基于Pro/E的锥形双螺杆三维造型设计

借助Pro/E现有的功能进行锥形双螺杆的实体造型和动态装配设计,可使锥形螺杆三维实体造型过程简化,其结果可以为同类产品的三维造型提供参考。     

梯形螺槽双螺杆几何造型的研究

对梯形螺槽同向和异向旋转双螺杆三维实体造型进行了研究,并对其中双螺杆设计、双螺杆中物料流动分析中的应用进行了探讨。结果表明,双螺杆几何造型程序具有很强的适用性和可操作性,为各种双螺杆几何参数的合理选择以及科学设计提供了强有力的工具。     

Photophysical properties of arylcarbonitrile derivatives: Synthesis, absorption and emission spectra, and quantum chemical studies

A new series of aromatic cyanovinyl compounds were synthesized via one-pot reactions of tri- or tetracyanoethylenes with nucleophilic reagents. The ground-state geometries and UV-vis absorption spectra of the compounds were computationally analyzed by means of density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations, respectively. None of the compounds were fluorescent in solution, but some showed intense emission in the solid state. The first excited singlet states (S₁) potential energy surfaces (PESs) were explored using complete active space SCF (CASSCF) calculations for the compounds in order to elucidate nonradiative decay mechanism that takes into account the involvement of conical intersections (CI).