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Yuan X.-D.,Shandong Jianzhu University | Yang X.-J.,Shandong Supervision and Inspection Institute for Product Quality
Wear | Year: 2010

The friction and wear properties of polytetrafluoroethylene (PTFE) coatings were studied in detail on a ball-on-disk wear tester under vacuum conditions. Experimental results showed that the friction coefficients of the PTFE coatings first increased with the increase of sliding velocity and then decreased with the increase of sliding velocity when the sliding velocity was higher than 1.2. m/s. The wear of the PTFE coating first decreased with the increase of sliding speed and then increased as the sliding speed increased. The friction coefficient decreased with the increase of load. The wear of PTFE coating first decreased with the increase of load and then increased with the increase of load when the load was higher than 6. N. The environmental pressure has insignificant effect on the friction coefficient of PTFE coating, and the friction coefficient of PTFE coating under air condition is slightly higher than that under vacuum condition. The wear first decreased with the increase of environmental pressure and then increased rapidly with the increase of environmental pressure when the pressure was higher than10. Pa. Scanning electron microscope (SEM) was utilized to investigate the worn surfaces, the self-lubricating films and debris. © 2010 Elsevier B.V.


Dong G.Y.,Shandong Jianzhu University | Yang X.L.,Shandong University | Cai L.Z.,Shandong University
Optics Express | Year: 2010

We have investigated for the first time the anomalous refractive effects of a photonic crystal (PhC) formed by holographic lithography (HL) with triangular rods arranged in a honeycomb lattice in air. Possibilities of left-handed negative refraction and superlens are discussed for the case of TM2 band with the index contrast n = 3.4:1. In contrast to the conventional honeycomb PhC made of regular rods in air, the HL PhCs show left-handed negative refraction over a wider and higher frequency range with high transmissivity (>90%), and the effective indices quite close to-1 for a wide range of incident angles with a larger all-angle left-handed negative refraction (AALNR) frequency range (Δω/ω ≈14.8%). Calculations and FDTD simulations demonstrate the high-performance negative refraction properties can happen in the holographic structures for a wide filling ratio and can be modulated by changing the filling ratio easily. © 2010 Optical Society of America.


Xue S.,Shandong Jianzhu University
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2012

The difference between shear stress and frictional force on shear failure plane and potential failure plane is defined as net shear stress, and the shear strain energy generated by the stress is defined as net shear strain energy. Based on shear failure assumption, the net shear strain energy density strength theory for geomaterials is proposed for material failures when the net shear stain energy density reaches certain value. The failure curve on the π plane of the theory is a slick curved triangle. The new theory was verified tentatively using true triaxial test data from the literature, and comparison between this theory, twin shear strength theory and Mohr-Coulomb strength theory was conducted. The results show that the error from the net shear stain energy density theory is relatively smaller. In addition, the net shear stain energy density theory degrades into the Mises strength theory when the uniaxial compressive strength is equal to the uniaxial tensile strength.


Zhang X.,Shandong Jianzhu University | Baron L.,Ecole Polytechnique de Montréal | Liu Q.,Shandong University of Finance and Economics | Boukas E.-K.,Ecole Polytechnique de Montréal
IEEE Transactions on Automatic Control | Year: 2011

In this technical note, constructive control techniques have been proposed for controlling feedforward nonlinear time-delay systems. The nonlinear terms admit an incremental rate depending on the input or delayed input. Based on the Lyapunov-Razumikhin theorem and Lyapunov-Krasovskii theorem, the delay-independent feedback controllers are explicitly constructed such that the closed-loop systems are globally asymptotically stable. An example is given to demonstrate the effectiveness of the proposed design procedure. © 2006 IEEE.


Li J.,Shandong Jianzhu University | Yu D.-H.,Chinese Academy of Sciences
CMES - Computer Modeling in Engineering and Sciences | Year: 2011

The composite rectangle (midpoint) rule for the computation of multidimensional singular integrals is discussed, and the superconvergence results is obtained. When the local coordinate is coincided with certain priori known coordinates, we get the convergence rate one order higher than the global one. At last, numerical examples are presented to illustrate our theoretical analysis which agree with it very well. © 2011 Tech Science Press.


Zhang X.,Shandong Jianzhu University | Liu Q.,Shandong University of Finance and Economics | Baron L.,Ecole Polytechnique de Montréal | Boukas E.-K.,Ecole Polytechnique de Montréal
Automatica | Year: 2011

This paper investigates the problem of global strong stabilization by state feedback, for a family of high order feedforward nonlinear time-delay systems. The uncertain nonlinearities are assumed to satisfy a polynomial growth assumption with an input or delayed input dependent rate. With the help of the appropriate LyapunovKrasovskii functionals, and a rescaling transformation with a gain to be tuned online by a dynamic equation, we propose a dynamic low gain state feedback control scheme. A simulation example is given to demonstrate the effectiveness of the proposed design procedure. © 2011 Elsevier Ltd. All rights reserved.


Zhou X.-J.,Shandong Jianzhu University
Gongcheng Lixue/Engineering Mechanics | Year: 2010

Jinan Olympic sports center is the primary venue for the 2009 National Sports Games. The design characteristics and structure health monitoring and monitoring results of Jinan Olympic sports center steel structure are introduced. The sports center includes a Stadium and three Gymnasiums, namely Stadium, Gymnasium, Swimming Gymnasium and Tennis Gymnasium. The stadium adopts a suspended lattice shell, and the others are folding space steel truss structure. Engineering practice shows that the assembled total model analysis of large spatial reticulated structures is important, the simplified calculation model of node is controlled by rigidly and hinged connection; the finite element analysis must be performed for the nodes of a complex space structure also. For a suspended lattice shell, the key is the establishment of the prestress system and the choice of the prestress size, the prestress value from the matrix equilibrium theory is proved to be feasible and effective. The key bar strain was monitored using Fiber Bragg Grating (FBG) sensor, and also achieved higher accuracy and better stability, and it can be applied to other similar structure monitoring.


Observation data sets from three different periods and 23 International GNSS Service (IGS) stations spread over the world were processed in static mode using four online free precise point positioning (PPP) services: Automatic Precise Positioning Service (APPS), GPS Analysis and Positioning Software, Canadian Spatial Reference System precise point positioning service, and Magic-PPP. The estimated positions of the 23 IGS stations were compared with the published values. The estimated zenith tropospheric delays (ZTDs) at these stations were compared with the corresponding IGS troposphere products published on the IGS Web site. Furthermore, in order to analyze PPP precision for short observation periods, GPS observation data sets with a sampling rate of 1 s collected by one CORS station were also processed by the four online PPP services. Calculation shows that the precision of daily solutions for north and east (N/E) components estimated by the four online PPP services can reach millimeter level, the precision of ellipsoid elevation (H) can reach 1–2 cm, and precision of ZTDs estimation results is approximately 1–2 cm. Compared with the corresponding values published on the IGS Web site, the precision of ZTDs estimated by APPS is higher than those estimated by the other three PPP online services; the differences between ZTDs by APPS and IGS values are mostly within ±1 cm. For PPP with short observation periods, the precision of N/E components within 2, 1, and 0.5 h observation periods can reach about 2–3, 2–7, and 3–8 cm, respectively, while the precision of H components is about 3–5, 5–12, and 10–18 cm, respectively. © 2014, Springer-Verlag Berlin Heidelberg.


Sha K.,Shandong Jianzhu University
Construction Management and Economics | Year: 2011

A research framework is developed to analyse the vertical governance, or transaction relationships between the client and its first-tier suppliers of construction projects in terms of project procurement route and payment terms. Starting from the particularity of the construction industry, reduced treatments that Williamson used in governance structure analysis are revised, and an assumption of 'second-order transformation' is proposed: as the information gap reaches a given level, and the proportion of specialized knowledge to deal with uncertainty exceeds a certain degree, the approach of selecting the governance structure of construction projects might deviate from the path anticipated by canonical theories. Both uncertainty and information cost are included in the analysis framework, and a principal-agent model is developed to analyse the procurement route and payment terms of construction projects. It is concluded that the information gap and the relative cost coefficient of information are decisive factors that determine the vertical governance structure of construction projects. They determine not only the time when 'second-order transformation' occurs, but also the distribution of 'weak incentive regions'. © 2011 Copyright Taylor and Francis Group, LLC.


Yang H.,Hong Kong Polytechnic University | Cui P.,Hong Kong Polytechnic University | Fang Z.,Shandong Jianzhu University
Applied Energy | Year: 2010

A large number of ground-coupled heat pump (GCHP) systems have been used in residential and commercial buildings throughout the world due to the attractive advantages of high efficiency and environmental friendliness. This paper gives a detailed literature review of the research and developments of the vertical-borehole GCHP technology for applications in air-conditioning. A general introduction on the ground source heat pump system and its development is briefly presented first. Then, the most typical simulation models of the vertical ground heat exchangers currently available are summarized in detail including the heat transfer processes outside and inside the boreholes. The various design/simulation programs for vertical GCHP systems primarily based on the typical simulation models are also reviewed in this paper. Finally, the various hybrid GCHP systems for cooling or heating-dominated buildings are well described. It is found that the GCHP technology can be used both in cold and hot weather areas and the energy saving potential is significant. © 2009 Elsevier Ltd. All rights reserved.

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