Dalian Jiaotong University is a university in Dalian, Liaoning, China under the provincial government. It has its larger campus near downtown Dalian and smaller campus in the High-Tech zone in Lüshun. Until 2004, it was known as Dalian Railway Institute . Wikipedia.
Wang H.T.,Dalian Jiaotong University |
Wang L.C.,Dalian University of Technology
Construction and Building Materials | Year: 2013
Since high strength of lightweight aggregate concrete leads to increased brittleness, fiber reinforcement should be considered for improving strength and ductility. Five groups of SFLWC specimens with different steel fiber volumes including 0.0%, 0.5%, 1.0%, 1.5% and 2.0% were tested to investigate the effect of steel fiber content on the static mechanical properties and the impact resistance of lightweight aggregate concrete. The static mechanical properties include the prismatic compressive strength, splitting tensile strength, first-crack flexural strength, flexural strength, and flexural toughness, etc. The impact resistance of SFLWC was obtained by a series of drop-weight tests, recommended by the ACI committee 544. The experimental results indicated that addition of steel fiber can greatly improve such mechanical properties as the splitting tensile strength, flexural strength, flexural toughness and impact resistance, but leads to a little effect on compressive strength. The test results also showed that a logarithmic relation exists between flexural toughness energy by means of the generated load-deflection curves from the flexural tests and the impact energy by means of drop-weight tests. Further more, the author suggests the feasible volume ratio of this kind of steel fiber is 1-1.5%. © 2012 Elsevier Ltd. All rights reserved.
Yan Y.,Dalian Jiaotong University |
Ji S.,Dalian University of Technology
International Journal for Numerical and Analytical Methods in Geomechanics | Year: 2010
A succinct 3D discrete element model, with clumps to resemble the real shapes of granular materials, is developed. The quaternion method is introduced to transform the motion and force of a clump between local and global coordinates. The Hertz-Mindlin elastic contact force model, incorporated with the nonlinear normal viscous force and the Mohr-Coulomb friction law, is used to describe the interactions between particles. The proposed discrete element model is used to simulate direct shear tests of the irregular limestone rubbles. The simulation results of vertical displacements and shear stresses with a mixture of clumps are compared well with that of laboratory tests. The bulk friction coefficients are calculated and discussed under different contact friction coefficients and normal stresses. © 2009 John Wiley & Sons, Ltd.
Tian R.,Dalian Jiaotong University |
Sun J.,Dalian Maritime University
International Journal of Hydrogen Energy | Year: 2011
TiN coating is successfully deposited on 316L by multi-arc ion plating. Corrosion behavior of TiN coated 316L is studied in 0.05 M H2SO 4 + 2 ppm F- simulating proton exchange membrane fuel cell (PEMFC) environments using electrochemical method, and interfacial contact resistance (ICR) is measured before and after potentiostatic polarization at operation potential for PEMFC. The TiN coated 316L exhibits promising ICR and improved corrosion resistance in simulated aggressive PEMFC environments. Only general overall corrosion is observed after potentiostatic polarization. Stable passive film has formed on the surface of the TiN coated 316L after potentiostatic polarization at the operation potential and results in a slight increase in the ICR. These results indicate that the TiN coated 316L is a candidate bipolar plate material for PEMFC stacks. Copyright © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Ma Y.,Dalian Jiaotong University
Nonlinear Analysis: Real World Applications | Year: 2012
In this paper, the LeslieGower predatorprey system with two delays is investigated. By choosing the delay as a bifurcation parameter, we show that Hopf bifurcations can occur as the delay crosses some critical values. In addition, special attention is paid to the global continuation of local Hopf bifurcations. Using a global Hopf bifurcation theorem for functional differential equations, we show the global existence of periodic solutions. © 2011 Elsevier Ltd. All rights reserved.
Liang B.,Dalian Jiaotong University
Nonlinear Analysis: Real World Applications | Year: 2011
This paper is devoted to studying a fourth-order parabolic equation ut+ε( uxxx)x-δ uxx=0 with Dirichlet boundary. By transforming the fourth order problem into an elliptic-parabolic system and applying a semidiscretization method, the existence, uniqueness and regularization of solutions are obtained. By introducing an energy functional through the semi-discrete problem, we use the iteration method to show that the solutions of the developing equation exponentially converge to a constant steady state solution as the time variable t→∞. Finally, we get the result of the asymptotic limit δ→0. © 2010 Elsevier Ltd. All rights reserved.
Wang Y.,Dalian Jiaotong University
High Performance Polymers | Year: 2015
Two novel thermally stable high-performance polymers, poly(arylene ether pyrimidine)s have been prepared with 2,4-dichloropyrimidine and 4,4-(hexafluoroisopropylidene)diphenol and bisphenol A by nucleophilic displacement reaction, respectively. Gel permeation chromatography results show that the obtained polymers exhibited 20,000 g mol-1 weight-average molecular weight. Thermal analysis studies indicate glass transition temperature values up to 156°C in differential scanning calorimetry and thermogravimetric analysis results revealed outstanding thermal stability up to 430 and 427°C for 5% weight loss under nitrogen and in air atmospheres, respectively. The polymers are soluble in a wide range of organic solvents, such as tetrahydrofuran, chloroform, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, and toluene at room temperature. The cutoff wavelengths of the resulting polymers were in the range of 278-283 nm. © 2014 The Author(s).
Liu F.,Dalian Jiaotong University |
Zhang Y.,Dalian Jiaotong University
Carbon | Year: 2010
Large area (∼cm2) multi-layer graphene film is synthesized in the substrate-free vapor phase. The scanning electron microscopy observation reveals that the graphene nanoflakes are either six- or five-sided, and the internal angles between adjacent sides are nearly 120° and 105°, respectively. The nucleation of hexagonal and pentagonal carbon rings leads to carbonaceous nuclei, which grow into six- or five-sided nanoflakes, respectively. A well-ordered and large-area graphene monolayer is formed by the interconnection of these flakes, and stacking of these monolayers results in the formation of a multi-layer graphene film. The creation of hexagonal and pentagonal carbon rings is considered to be important for the easy production of large area multi-layer graphene at large scale. © 2010 Elsevier Ltd. All rights reserved.
Liu Q.,Dalian Jiaotong University
Acta Mechanica | Year: 2013
There are two typical definitions for the macroscopic average couple stress tensor in the literature, which brings confusion and difficulty to the establishment of Hill's lemma for heterogeneous Cosserat continuum. Besides, some boundary conditions on the representative volume element (RVE) commonly used in the homogenization method cannot be properly determined by the existing version of Hill's lemma of Cosserat continuum. To deal with these issues, Hill's lemma for micro-macro homogenization modeling of Cosserat continuum is further investigated in the frame of the average-field theory in this paper. An intermediate form of Hill's lemma is constructed in which the micromechanically based definition of the average couple stress tensor is not specified. By substituting two existing definitions of the average couple stress tensor into the presented intermediate form, not only the previous version of Hill's lemma is derived, but also a new version of Hill's lemma is obtained. According to the new version of Hill's lemma, more versatile RVE boundary conditions in the strong form can be properly given, and the periodic RVE boundary conditions in the weak form are also constructed. © 2012 Springer-Verlag Wien.
Tian R.,Dalian Jiaotong University
Journal of Power Sources | Year: 2011
Chromium nitride/Cr coating has been deposited on surface of 316L stainless steel to improve conductivity and corrosion resistance by physical vapor deposition (PVD) technology. Electrochemical behaviors of the chromium nitride/Cr coated 316L stainless steel are investigated in 0.05 M H 2SO4 + 2 ppm F- simulating proton exchange membrane fuel cell (PEMFC) environments, and interfacial contact resistance (ICR) are measured before and after potentiostatic polarization at anodic and cathodic operation potentials for PEMFC. The chromium nitride/Cr coated 316L stainless steel exhibits improved corrosion resistance and better stability of passive film either in the simulated anodic or cathodic environment. In comparison to 316L stainless steel with air-formed oxide film, the ICR between the chromium nitride/Cr coated 316L stainless steel and carbon paper is about 30 mΩ cm2 that is about one-third of bare 316L stainless steel at the compaction force of 150 N cm-2. Even stable passive films are formed in the simulated PEMFC environments after potentiostatic polarization, the ICR of the chromium nitride/Cr coated 316L stainless steel increases slightly in the range of measured compaction force. The excellent performance of the chromium nitride/Cr coated 316L stainless steel is attributed to inherent characters. The chromium nitride/Cr coated 316L stainless steel is a promising material using as bipolar plate for PEMFC. © 2010 Elsevier B.V. All rights reserved.
Dalian Jiaotong University, Yingkou Yinhe Magnesium And Aluminum Alloy Co. and Beijing Wonderroad Magnesium Technology Co. | Date: 2011-02-16
The present invention relates to a magnesium alloy honeycomb board and a production process thereof. The magnesium alloy honeycomb board is formed through the glue-jointing of an upper panel, a lower panel and a honeycomb core structure, and is characterized in that: both the upper and lower panels are made of magnesium alloy sheets with a thickness of 0.6 to 3.5mm, and the honeycomb core structure is made of magnesium alloy foil with a thickness of 0.08 to 0.25mm; the thickness of the honeycomb board is within 8 to 45mm, the thickness of the honeycomb core structure is within 6 to 38mm, the height of the hexagonal honeycomb aperture is within 5 to 15mm, and the fillet radius is within 0.4 to 1.2mm. The honeycomb core structure is a regularly-hexagonal one formed through the rolling, cutting, plastic bending, accurate forming and positioned bonding of high-strength magnesium alloy, and is then glue-jointed with the high-strength magnesium alloy panels to form the magnesium alloy honeycomb board with high strength and ultra-light weight through pressurizing solidification. Being capable of realizing the weight reducing effect, the magnesium alloy honeycomb board not only can be used as components like wallboard, floor, partition board, etc. in such transportation equipment as spacecrafts, aircrafts, light-weight rapid trains, urban railway trains, etc., but also can be applied in other structures as panel or partition board.