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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
YUAN Jing HE ZhengJia ZI YanYang & LIU Han State Key Laboratory for Manufacturing Systems Engineering School of Mechanical Engineering Xi’an Jiaotong University Xi’an China Shanghai Baosteel Industry Inspection Corporation Baosteel Group Corporation Shanghai 《中国科学E辑(英文版)》2009,52(10):2801-2809
Fault diagnosis of rolling mills, especially the main drive gearbox, is of great importance to the high quality products and long-term safe operation. However, the useful fault information is usually submerged in heavy background noise under the severe condition. Thereby, a novel method based on multiwavelet sliding window neighboring coefficient denoising and optimal blind deconvolution is proposed for gearbox fault diagnosis in rolling mills. The emerging multiwavelets can seize the important signal proce... 相似文献
992.
ZhenXia Wang XinNian Li CuiLan Ren ZhenZhong Yong JianKang Zhu WenYun Luo XiaoMing Fang 《中国科学E辑(英文版)》2009,52(11):3215-3218
The experimental investigations on the interaction between Ag-nanocrystal particles (Ag-NCPs) and carbon nanotubes (CNTs)
in Ag-nanocrystal particles/carbon nanotubes (Ag-NCPs/CNTs) hybrid structures were reported. The growth of Ag-NCPs on multiwalled
carbon nanotubes (MWCNTs) was carried out by thermal evaporation deposition. High-resolution transmission electron microscopy
and X-ray diffraction analyses revealed that Ag-NCPs had the crystal lattice feature of face-centered cube (fcc). The growth
of Ag-NCPs on MWCNTs induced the cross-section deformation of MWCNT. The experimental results also showed that the synthesized
Ag-NCPs/CNTs hybrid structure appeared as quasi-one dimensional nanowires containing the Ag-NCP/CNT hetero-junction. There
was local cross-section deformation on MWCNTs at the interface of hetero-junction. These results involve the important topic
about fundamental and practical studies for structure of MNCPs on CNTs and also find clues to further research of Ag nanocrystal
growing on MWCNTs and related Ag-CNT interaction. 相似文献
993.
JuYing Wu ChengXi Zhou QingWen Zhu EnRong Li Ge Dai Long Ba YuHong Huang Jun Mei 《中国科学E辑(英文版)》2009,52(12):3497-3503
The ruthenium oxide nanoparticles with size less than 20 nm were fabricated by annealing the metallic ruthenium nanoparticles
in air, which were synthesized by using the thermal reduction in the polyol solution. The rutile structure of the ruthenium
oxide was proved by using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The oxide has
good electron conductivity. The surface of the ruthenium oxide was modified by a vinyl silane coupling agent. The assembling
of the silane to the oxide surface was proved by Infrared (IR) absorption spectroscopy. By mixing the nanoparticles with poly(methylvinylsiloxane)
(PMVS) silicone rubber, a composite filled with dispersive conducting phase was fabricated. The temperature dependent conductivity
shows that the electron transportation through composite is mainly dominated by tunneling. The measurement of piezoresistance
shows that the composite at low strain has high piezoresistance repeatability. The 3D reconstruction images of the composite
filled with carbon black or ruthenium oxide show that the aggregation of the nanoparticles differs much for two composites.
The narrow distribution range of the particle size was thought to be the main factor for the high piezoresistance recurrence. 相似文献
994.
This paper presents a physically-based integrated hydrologic model that can simulate the rainfall-induced 2D surface water
flow, 3D variably saturated subsurface flow, upland soil erosion and transport, and contaminant transport in the surface-subsurface
system of a watershed. The model couples surface and subsurface flows based on the assumption of continuity conditions of
pressure head and exchange flux at the ground, considering infiltration and evapotranspiration. The upland rill/interrill
soil erosion and transport are simulated using a non-equilibrium transport model. Contaminant transport in the integrated
surface and subsurface domains is simulated using advection-diffusion equations with mass changes due to sediment sorption
and desorption and exchanges between two domains due to infiltration, diffusion, and bed change. The model requires no special
treatments at the interface of upland areas and streams and is suitable for wetland areas and agricultural watersheds with
shallow streams. 相似文献
995.
Irrigation practices greatly affect sustainable agriculture development. In this study, we investigated the effects of irrigation
efficiency on water flow and chemical transport in soils, which had significant impact on the environment. Field dye staining
experiments were conducted at different soils with various irrigation amount. Image analysis was conducted to study the heterogeneous
flow patterns and their relationships with the irrigation efficiency. Irrigation efficiency and its environmental effects
were evaluated using various indictors, including application efficiency, deep percolation ratio, storage efficiency, and
uniformity. Under the same irrigation condition, soil chemical distributions were more heterogeneous than soil water distributions.
The distributions were mainly affected by soil texture, initial soil water content, and irrigation amount. Storage efficiency,
irrigation uniformity, and deep percolation ratio increased with irrigation amount. Since the chemical distribution uniformity
was lower than the water uniformity, the amount of chemical leaching increased sharply with decrease of irrigation uniformity,
which resulted in high environmental risks of groundwater pollution. 相似文献
996.
Earth pressure balance control for EPB shield 总被引:1,自引:0,他引:1
This paper mainly deals with the critical technology of earth pressure balance (EPB) control in shield tunneling. On the assumption that the conditioned soil in the working chamber of the shield is plasticized, a theoretical principle for EPB control is proposed. Dynamic equilibrium of intake volume and discharge volume generated by thrust and discharge is modeled theoretically to simulate the earth pressure variation during excavating. The thrust system and the screw conveyor system for earth pressure cont... 相似文献
997.
The viscoelastic multi-dimensional earthquake isolation and mitigation device is a new kind of passive control device, which can perform its "name-giving" task of earthquake isolation and earthquake mitigation simultaneously. In order to quantify its vertical earthquake isolation and mitigation effect on structures, firstly, shaking table tests on steel frame structures with and without the devices were carried out; secondly, analysis on dynamic characteristics and dynamic responses of the structures was al... 相似文献
998.
The spherical gear is a gear-driven mechanism with two degrees of freedom (DOF), which can transfer spatial motion and power. Grinding machining of the spherical gear is performed with a plate grinding wheel by using generating method, and based on mathematical model of the plate grinding wheel, the mathematical model of the spherical gear is set up. And then, the meshing model of a spherical gear pair is developed and the tooth contact analysis (TCA) of the spherical gear pairs is performed. After that, th... 相似文献
999.
The ablation in solid-propellant rocket nozzle is a coupling process resulted by chemistry, heat and mass transfer. Based on the heat and mass transfer theory, the aero-thermo-dynamic, and thermo-chemical kinetics, the thermal-chemical ablation model is established. Simulations are completed on the heat flow field and chemical ablation in the nozzle with different concentrations, frequency factors and activation energy of H2. The calculation results show that the concentration and the activation energy of H... 相似文献
1000.
Summary Polypyrrole (PPy) composite films with different contents of Fe3O4 were prepared by in-situ polymerization of pyrrole in aqueous solutions. The dependence of dc current changes on the response
of the samples exposure to NH3 vapor has been investigated. The results shows the composite films are more stable than the pristine ones after being exposed
to NH3 vapor. Meanwhile, the response time was reduced with increasing the Fe3O4 content in the films. The results might be originated from the structural changes in the PPy films caused by the addition
of Fe3O4. 相似文献