神经网络智能诊断技术在混凝土结构中的理论实现与展望

混凝土结构诊断技术是现代建筑工业中的一个重要课题。基于人工神经网络的智能诊断,其融合了计算机技术与神经网络技术,并结合了工程设备的特征,它具有非线性、快速、精确等优点,更接近工程实际;同时,具有美好的发展前景。     

控制爆破技术在井下煤仓工程中的综合应用

义马煤业集团义络煤业公司在水平延深中,根据煤仓工程的特点,综合应用控制爆破技术解决三水平施工与二水平生产的矛盾,取得了较好的施工效果。     

采用起重机吊装桥梁工程的施工方法

采用起重机吊装预制梁,具有施工机具简单、易于操作、成本低、工期短、质量安全易于保证等优点。对于施工操作场地开阔、道路交通方便的中小桥梁工程,采用起重机吊装是一种较好的施工方法。     

水利工程模型试验计算机测量与控制系统

采用计算机测量与控制系统应用于水利工程模型试验,设计应用先进的水流循环系统、电磁流量计、电子式电动调节阀、控制接口和软件组成计算机流量闭环自动控制系统;计算机测量与控制系统通过实际使用运行,证明达到了设计指标的要求,大大提高了模型试验测量与控制的精度和工作效率,缩短了模型试验周期,有利于水利工程研究成果质量和科研水平的提高.     

轿车悬架弹性橡胶衬套弯曲刚度的工程算法

在线性前提下,根据橡胶衬套径向刚度在线性范围内,找出了求解橡胶衬套弯曲刚度的工程算法,经过试验验证,具有工程使用价值.     

煤矿采矿工程中的采矿工艺与技术

阐述了煤矿采矿工程的特点,分析了目前常用的采矿工艺与技术,主要包括充填采矿工艺、空场采矿工艺、煤与瓦斯联合开采技术,并对智能化采矿技术的发展做了简要分析.     

IGC synthesis of tin nanophase particles Part I: Study on convection gas currents in IGC chamber

Abstract

In order to optimise process variables during the synthesis of tin nanophase particles in an inert gas condensation (IGC) chamber, a two-dimensional finite difference method (FDM) simulation on convection gas currents is proposed and calculated for various boundary conditions. The convection gas velocity and temperature for the 95×105 positions in the chamber were calculated by simulation and compared with experimental results. In the FDM simulation, the governing equations consisted of continuity, momentum, and energy equations. The effects of convection gas pressure, evaporation temperature, position of the evaporation source, and chamber size on the formation of convection currents were investigated by the FDM simulation and experiments. It turned out that among various process variables, the convection gas pressure played the most important role in the formation of the convection gas current that gave rise to an impact on the shape and size of synthesised tin nanophase particles.     

Lunar Habitat Micrometeoroid and Radiation Shielding: Options, Applications, and Assessments

Various shielding approaches to protect lunar habitats from micrometeoroid and radiation hazards present major trade-off considerations. Popular scenarios that envision covering modules with in situ regolith will necessitate means to excavate and move large amounts of material; will complicate evolutionary outpost growth; and may require long tunnels between connecting pressurized elements. Strategies that incorporate shielding materials into module structures or internal shelters add very substantial launch mass penalties. Utilization of water bladders can make efficient use of consumable/recyclable supplies, but may impose excess capacity deliveries at early development stages. This paper addresses these different shielding approaches from a top-level application perspective, highlighting pros and cons of each. Examples draw upon research and design investigations undertaken by the Sasakawa International Center for Space Architecture in support of separate National Aeronautics and Space Administration (NASA) contracts awarded to teams headed by Boeing and ILC-Dover for a “Minimum Functionality Habitation Systems Concept Study.” Comprehensive team study results were presented to NASA in February 2009, and have been released as public information.     

Nanoclays: Two-dimensional shuttles for rare earth complexes in aqueous solution

Nanoclays are shown to be attractive substrates in at least two major respects. Firstly, Hectorite analogous commercial clays (“Laponite”) can facilitate the usage of luminescent rare earth ions in aqueous solution, as their adherence to the clay surface strongly reduces water coordination and thus enables dramatically improved emission intensities. This also holds true for complexes of Tb³⁺, which coordinate water in their native crystalline state, as demonstrated for tris(bipyiridine) complexes. For these, the laponite interaction affords a 16-fold gain in emission intensity in aqueous solution over the dissolved complex. Secondly, the two-dimensional, disk-like morphology of the clays enables a sufficient proximity of Ce³⁺ and Tb³⁺ to allow an energy transfer even at comparably low solution concentrations. In partially laminated, solid powders the efficiencies of the corresponding interlayer species decrease due to intimate interactions with the surrounding silicate and interlayer water, which can, however be counteracted by keeping the disks apart with long-chain, alkylammonium cations as spacers between the disks.     

Structure inhibited pit initiation in a Ni-Nb metallic glass

A model metallic glass Ni₅₀Nb₅₀, which would undergo a polymorphous transformation during devitrification, was selected to clarify the correlation of amorphous structure with corrosion. The electrochemical polarization behaviour, film breakdown and composition of surface film have been studied in detail by comparing the amorphous alloy with its crystalline counterparts. Interestingly, it was found that the pit initiation is inhibited greatly on amorphous sample relative to the crystallized one. The origin is thought to be related to the defective interface beneath passive film that inhibits the formation of pitting precursors in corrosion.