By using ABAQUS/Explicit, the dynamic process of an offshore wind turbine(OWT) stricken by a ship of 5000DWT in the front direction is simulated. The OWT is located on a large-scale prestressing bucket foundation constructed by an integrated installation technique. According to the simulation results, under the ship collision, a certain range of plastic zone appears within a local area of arc transition structure of the bucket foundation, and the concrete plastic zone is seriously damaged. As the stress level of OWT tower is relatively low, the OWT tower is less affected. A great inertial force is generated at the top of the OWT tower as the mass of nacelle and blades is up to 400 t. The displacement of the tower is in the opposite direction of the ship collision at the end of 1 s under the action of inertial force. There is only a minor damage in the ship bow. Most of the kinetic energy is transformed into the plastic dissipation and absorbed by the arc transition structure of bucket foundation.

Due to the complex nature of multi-source geological data, it is difficult to rebuild every geological structure through a single 3D modeling method. The multi-source data interpretation method put forward in this analysis is based on a database-driven pattern and focuses on the discrete and irregular features of geological data. The geological data from a variety of sources covering a range of accuracy, resolution, quantity and quality are classified and integrated according to their reliability and consistency for 3D modeling. The new interpolation-approximation fitting construction algorithm of geological surfaces with the non-uniform rational B-spline (NURBS) technique is then presented. The NURBS technique can retain the balance among the requirements for accuracy, surface continuity and data storage of geological structures. Finally, four alternative 3D modeling approaches are demonstrated with reference to some examples, which are selected according to the data quantity and accuracy specification. The proposed approaches offer flexible modeling patterns for different practical engineering demands.

An improved test rig providing both the heat and cold source was used to perform thermal response test (TRT), and the line source model was used for data analysis. The principle of determining the temperature difference between the inlet and outlet of test well can keep the heating or cooling rate constant, along with a reduced size of test rig. Among the influencial factors of the line source model, the temperature difference was determined as the most important, which agreed with the test results. When the gravel was taken as the backfill material, the soil thermal conductivities of heating and cooling at the test place were 1.883 W/(m·K) and 1.754 W/(m·K), respectively, and the deviation of TRT between heating and cooling soil was 6.8%. In the case of fine sand, the thermal conductivities of heating and cooling were 1.541 W/(m·K) and 1.486 W/(m·K), respectively, and the corresponding deviation was 6%. It was also concluded that different velocities of water had less influence on TRT than the temperature difference.

A micro-sized tube heat exchanger (MTHE) was fabricated, and its performance in heat transfer and pressure drop was experimentally studied. The single-phase forced convection heat transfer correlation on the sides of the MTHE tubes was proposed and compared with previous experimental data in the Reynolds number range of 500–1 800. The average deviation of the correlation in calculating the Nusselt number was about 6.59%. The entrance effect in the thermal entrance region was discussed. In the same range of Reynolds number, the pressure drop and friction coefficient were found to be considerably higher than those predicted by the conventional correlations. The product of friction factor and Reynolds number was also a constant, but much higher than the conventional.

In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the unified reference coordinate system. A flexible planar calibration pattern was introduced to the calibration process, which can be arbitrarily placed and from which the known feature points can be extracted to construct other unknown feature points. With the known intrinsic parameters, the laser projector plane equation was fitted by the multi-noncollinear points, which were acquired through the principle of triangulation and the projective invariance of cross ratio. With this method, the strict alignment and multiple times of coordinate transformation can be avoided. Experimental results showed that the arithmetic mean of the root mean square (RMS) error of distance was 0.000 7 mm.

Irradiated by infrared laser, the surface reducibility and adsorbability of Cu-Cr complex could be improved, owing to the interaction of photo-fragmentation and laser texturing. Analyzed by the binding energy spectra and the auger spectra, the valence states of chromium ion and copper ion were +3 and +1 after radiation respectively, which still had the reducibility to release electrons. In contrast with the near-infrared (NIR)1 064 nm and mid-infrared (MIR) 10 600 nm laser at the same average output power of 15 W, the reduced metal percentage in the Cu-Cr complex was obviously distinguished at the depth from nanometer to micron. After chemical plating, the average coating thickness and mean-square deviation of the NIR sample were 11.61 μm and 0.30 for copper layer, and 2.69 μm and 0.08 for nickel layer. The results were much better than those of the MIR sample.

The combined use of dry cooling (DC) system and dedicated ventilation (DV) system to decouple cooling and dehumidification process for energy efficiency was proposed for subtropical climates like Hong Kong. In this study, the energy performance and condensation risk of the use of DCDV system were examined by analyzing its application in a typical office building in Hong Kong. Through hour-by-hour simulation using actual equipment performance data and realistic building and system characteristics, it was found that with the use of DCDV system, the annual energy consumption could be reduced by 54% in comparison with the conventional system (constant air volume with reheat system). In respect of condensation risk, it was found that the annual frequency of occurrence of condensation on DC coil was 35 h. Additional simulations were conducted to examine the influence of different parameters on the condensation risk of DCDV system. Measures to ensure condensate-free on DC coil were also discussed.

The copolymerization of CO and styrene catalyzed by Pd/C toward the formation of polyketones (PK)was studied in the N-valeronitrile-N′-methylimidazolium hexafluorophosphate ([C₄CNmim]⁺PF₆ ^-) medium. The synthesized PK was characterized by Fourier transform infrared(FTIR), elemental analysis, ¹³C-nuclear magnetic resonance (¹³C-NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and gel permeation chromatography (GPC). The supported ionic liquid film on the surface of Pd/C catalyst can prevent the products from covering the hole of active carbon due to its chemical stability and weak coordination ability with metal ions, and thus efficiently improve the catalytic activity. The effects of different amounts of ionic liquid on the catalytic activity and reusability of the catalyst and the molecular weight of PK were discussed. When the usage of ionic liquid is 10wt% (0.1 g ionic liquid / 1 g active carbon carrier) and the theoretical content of Pd²⁺ is 5wt% (0.05 g Pd²⁺/ 1 g active carbon carrier), the highest catalytic activity 2 963.64 gSTCO/(gPd · h) is achieved with the molecular weight and polydispersity index of PK as M _n = 9 684, M _w = 13 452 and M _w/M _n = 1.389.

The evolution of the surface oxide film along the depth direction of typical aluminum alloy under medium-temperature brazing was investigated by means of X-ray photoelectron spectroscopy (XPS). For the alloy with Mg content below 2.0wt%, whether under cold rolling condition or during medium-temperature brazing process, the enrichment of Mg element on the surface was not detected and the oxide film was pure Al₂O₃. However, the oxide film grew obviously during medium-temperature brazing process, and the thickness was about 80 nm. For the alloy with Mg content above 2.0wt%, under cold rolling condition, the original surface oxide film was pure Al₂O₃. However, the Mg element was significantly enriched on the outermost surface during medium-temperature brazing process, and MgO-based oxide film mixed with small amount of MgAl₂O₄ was formed with a thickness of about 130 nm. The alloying elements of Mn and Si were not enriched on the surface neither under cold rolling condition nor during mediumtemperature brazing process for all the selected aluminum alloy, and the surface oxide film was similar to that of pure aluminum, which was almost entire Al₂O₃.

In order to reduce noise effectively in the welding defect image and preserve the minutiae information, a noise reduction method of welding defect image based on nonsubsampled contourlet transform (NSCT) and anisotropic diffusion is proposed. Firstly, an X-ray welding defect image is decomposed by NSCT. Then total variation (TV) model and Catte_PM model are used for the obtained low-pass component and band-pass components, respectively. Finally, the denoised image is synthesized by inverse NSCT. Experimental results show that, compared with the hybrid method of wavelet threshold shrinkage with TV diffusion, the method combining NSCT with P_Laplace diffusion, and the method combining contourlet with TV model and adaptive contrast diffusion, the proposed method has a great improvement in the aspects of subjective visual effect, peak signal-to-noise ratio (PSNR) and mean-square error (MSE). Noise is suppressed more effectively and the minutiae information is preserved better in the image.

A modified Lindstedt-Poincaré (LP) method for obtaining the resonance periodic solutions of nonlinear non-autonomous vibration systems is proposed in this paper. In the modified method, nonlinear non-autonomous equations are converted into a group of linear ordinary differential equations by introducing a set of simple transformations. An approximate resonance solution for the original equation can then be obtained. The periodic solutions of primary, super-harmonic, sub-harmonic, zero-frequency and combination resonances can be solved effectively using the modified method. Some examples, such as damped cubic nonlinear systems under single and double frequency excitation, and damped quadratic nonlinear systems under double frequency excitation, are given to illustrate its convenience and effectiveness. Using the modified LP method, the first-order approximate solutions for each equation are obtained. By comparison, the modified method proposed in this paper produces the same results as the method of multiple scales.

The existing oil import dependence index cannot exactly measure the economic cost or scales, and it is difficult to describe the economical aspect of oil security. To measure the foreign dependence of one country’s economy and reflect its oil economic security, this paper defines the net oil import intensity as the ratio of net oil import cost to GDP. By using Divisia Index Decomposition, the change of net oil import intensity in five industrialized countries and five newly industrialized countries during 1971–2010 is decomposed into five factors: oil price, oil intensity, oil self-sufficiency, domestic price level and exchange rate. The result shows that the dominating factors are oil price and oil intensity; moreover, the newly industrialized countries have higher net oil import intensity than industrialized countries.