Time filter

Source Type

Gao J.-Y.,Tianjin Vocational Institute | Zheng H.-X.,Tianjin University of Technology and Education
Progress in Electromagnetics Research Letters | Year: 2013

A one-step leapfrog alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method for lossy media is presented. Different from the method provided by others, the proposed method is originated from the conventional ADI-FDTD method instead of considering the leapfrog ADI-FDTD method as a perturbation of the conventional explicit FDTD method. Its unconditional stability is analytically proven through a method that combines the von Neumann method with the Jury criterion. In addition, its unconditional stability and computational efficiency are verified through numerical experiments.

Junhai M.,Tianjin University | Junling Z.,Tianjin University | Junling Z.,Tianjin Vocational Institute
Nonlinear Dynamics | Year: 2012

In the oligopoly insurance market, we assumed that some oligarchs make two-period delay decisions in bounded rationality and expectation, respectively, and others make decisions with bounded rationality without the condition of delay. There also exist two cases in which only one oligarch makes a delayed decision and two oligarchs make delayed decisions at the same time. Based on the analysis of these situations, we established the corresponding dynamic price game models.We then performed a numerical simulation to the complexity state of the system with different conditions such as stability, bifurcation, and chaos, and analyzed the profits of different oligarchs when the system is in different states. The results showed that when only one oligarch makes a delayed decision, with the decrease in the price weight of period t and increase in that of periods t - 1 and t - 2, the system's stable region in the direction of the price adjustment of the oligarch with a delayed decision gets smaller. However, when there are two oligarchs with a delayed decision in the system, in the case where the delay parameters of oligarch 1 remain unchanged and the price parameters of different periods of oligarch 2 change, the system's stable region in the direction of the price adjustment of oligarch 1 does not have the obvious change as that when only one oligarch makes a delayed decision. This showed that the sensibility of one oligarch in the direction of its own price adjustment is lower than other oligarchs. In addition, in the same system with delay and when the system is in chaos, the total profit of the oligarchs is obviously less than that when the system is in a stable state. However, the use of a delayed decision may not enhance the oligarch's competitive advantages. Finally, the variable feedback control method is used to effectively control the chaos in the system. © Springer Science+Business Media B.V. 2012.

Zong Q.,Tianjin University | Zhao Z.-S.,Tianjin University | Zhang J.,Tianjin Vocational Institute
IET Control Theory and Applications | Year: 2010

A higher order sliding mode control (SMC) with self-tuning law algorithm for uncertain non-linear systems is proposed. The method can be viewed as the finite time stabilisation based on geometric homogeneity and integral SMC. In order to reduce chattering and solve system uncertainties with unknown bound, a bipolar sigmoid function on-line adaptation and an adjustable control gain tuning approach without high-frequency switching are developed. Control system stability is ensured using the Lyapunov method. An example is given to show the effectiveness of the developed approach. © 2010 The Institution of Engineering and Technology.

Hong Z.,Tianjin Vocational Institute
Advanced Materials Research | Year: 2011

Anti-corrosion coating in desulphurization flue of one wet flue gas desulfurization equipment (FGD) (model 1 and model 2) was designed and studied according to environmental and technical parameters of a coal-fired power plant. And relevant design requirements were confirmed. Application results showed that polyureas has wear and high temperature physical properties, so that it can be used in flue desulfurization equipment for anticorrosion. When the construction of a thickness of 2.0 mm, the high-temperature polyureas protective coating appearance smooth, EDM(electric discharge machining) 100% pass rate, adhesion 10.8 MPa, at 160 °C environment still had outstanding performance, that make sure it could reach its design life of the flue based on estimating the corrosion margin.

He T.,Tianjin Vocational Institute
Advanced Materials Research | Year: 2014

SiO2 is a good performance of high temperature wave-transparent materials, but the impact of the material properties of the components of the wave through it there are some drawbacks. This study intended to determine the theoretical dielectric properties of this material. Based on Debye theory, describes the dielectric properties of the composite material at high temperature multi-scale model, discuss the impact of factors on the micro and mesoscopic dielectric properties. © (2014) Trans Tech Publications, Switzerland.

Li Z.,Tianjin Vocational Institute
Progress in Civil, Architectural and Hydraulic Engineering - Selected Papers of the 4th International Conference on Civil, Architectural and Hydraulic Engineering, ICCAHE 2015 | Year: 2016

Prestressed steel structure is an important measure of the construction level of a nation. For prestressed steel structure construction, both in the construction phase, or in the normal use stage, to monitor their health status is necessary. In order to make the monitoring more vivid, concrete, and humane, we developed the visual monitoring system by using three-dimensional (3D) technology. The system consists of real-time communication subsystem, 3D display subsystem and safety warning subsystem. By observing the 3D model, we can know the monitoring data of the real buildings. At last, the safety warning for the prestressed steel structure was implemented. © 2016 Taylor & Francis Group, London.

Yu Y.,Tianjin Vocational Institute
Applied Mechanics and Materials | Year: 2014

To construct low-carbon city, the development trend of green living is gradually clear, low-carbon has become the new trend of various fields' development, and green planning, green building and low-carbon consumption also have become the mainstream of society. From the green low-carbon and minimalistic design of the packaging field starting, first expounded the importance of packaging materials' green low-carbon and its superiority analysis, and then the use of random choice model makes science choice analysis of packaging materials, further using the deterministic model analyzes the layout and color of packaging design, to provide the theoretical basis and practical new model for green low-carbon packaging and minimalistic design. © (2014) Trans Tech Publications, Switzerland.

Hu X.,Tianjin Vocational Institute
TMS Light Metals | Year: 2015

The effects of LiOH, Na2MoO4, and BTA on the corrosion behaviors of copper and copper-nickel alloy in 60% LiBr solution was studied by AC impedance measurements. Results indicated that LiOH, BTA, and Na2MoO4 could inhibited the corrosion of copper and copper-nickel alloy in LiBr solution respectively. When they were used together, the inhibition efficiency was higher than that of used one of them. They behaved a synergistic effect on inhibiting the corrosion of copper and copper-nickel alloy in 60% LiBr solution. It presented that when the concentration of LiOH, Na2MoO4 and BTA was 0.10mol/L, 150mg/L and 150mg/L, respectively, they behaved the highest inhibition efficiency on the corrosion of copper and copper-nickel alloy in 60% LiBr solution.

Duan J.J.,Tianjin Vocational Institute
Proceedings of the International Conference on Management, Information and Educational Engineering, MIEE 2014 | Year: 2015

This paper takes innovation network theory as research basis, to explore the differentiated impact on network embeddedness to enterprise technological innovation performance in different network embeddness relationship. Analysis of network embeddedness how to influence “enterprises social capital” and “across organizational knowledge management”, thus effecting the performance of enterprise technological innovation, and studies the moderating effect of external environment variables in the process of network embeddedness and network competence influencing on enterprise’s technological innovation performance. It could help enterprise to understand the technological innovation performance enhancing path in a network environment, and could make enterprise to grasp the effect mechanism of network embeddedness, network competence and technological innovation performance, and could establish the theoretical foundation for enterprises to strengthen innovation network construction, to improve network competence and enhance competitive advantages. © 2015 Taylor & Francis Group, London.

Wang H.-Y.,Tianjin Vocational Institute
Zhonghua Shiyan Yanke Zazhi/Chinese Journal of Experimental Ophthalmology | Year: 2013

Background: Nomal binocular vision is achieved through accommodation and vergence. Anisometropia is associated with abnormal visual development, but its impact on accommodation and vergence is unknown. This study is helpful to make a reaonable correction plan for anisometropia. Objective: This clinical study was to examine the binocular vision function in myopic anisometropia and evaluate the influence of myopic anisometropia on binocular vision function. Methods: Seventy subjects with myopic anisometropia ≥ 1.0 D were recruited in Tianjin Eye Hospital and Tianjin Vocational Institute from 2006 to 2009. The subjects were assigned to the low anisometropia group with the 1.0 D ≤ spherical equivalent difference < 2.5 D and the moderate and high anisometropia group with spherical equivalent difference ≥ 2.5 D, and other 35 individuals with spherical equivalent difference < 1.0 D were enrolled as the without anisometropia group. Binocular vision function parameters were examined in all the individuals, including comprehensive refractometer to check the diopter, Worth 4 dot to examine the binocular vision function, different distance of vertical fusional amplitudes, accommodative convergence/accommodation (AC/A) and stereoscopic vision. Written informed consent was obtained from each subject prior to the study. Results: After anisometropia was completely corrected, the normal rate of Worth 4 dot examination was 94.3%, 80.0% and 60.0% in the without anisometropia group, low anisometropia group, moderate and high anisometropia group, respectively, showing a statistical difference among groups (χ2 = 12.137, P < 0.05), and the normal rate of 4 dot was less, and that of 5 dot was higher in the moderate and high anisometropia group compared with the without anisometropia group and low anisometropia group (P < 0.05). No significant difference was found in the normal rate for phoria of distance among the three groups (χ2 = 4.489, P = 0.344). The normal rate for near phoria of distance was 65.7%, 42.9% and 37.1% in the without anisometropia group, low anisometropia group, moderate and high anisometropia group, respectively, with significant difference among them (χ2 = 6.045, P < 0.05). The normal rate of stereopsis was 91.4%, 77.1% and 54.3% in the without anisometropia group, low anisometropia group, moderate and high anisometropia group, respectively, which was statistically different among groups (χ2 =12.863, P = 0.002), and that in the moderate and high anisometropia group was significant declined in comparison with the without anisometropia group (χ2 = 12.208, P < 0.05). The difference of distance phoria, AC/A, negative relative accommodation (NRA), positive relative accommodation (PRA), accommodation amplitude and binocular accommodative lag were statistically different among groups (P > 0.05). Conclusions: The normal rate of the stereopsis, Worth 4 dot and the phoria of near distance are decreased with the increase of anisometropia, but other ocular motor parameters are normal in anisometropic subject. Copyright © 2013 by the Chinese Medical Association.

Loading Tianjin Vocational Institute collaborators
Loading Tianjin Vocational Institute collaborators