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Huang Y.,Tianjin University | Zhang J.,Tianjin Sino German Vocational Technical College | Li X.,Tianjin Polytechnic University | Tian L.,Tianjin University
International Journal of Advanced Manufacturing Technology | Year: 2014

Thermal error is one of primary reasons affecting the cutting accuracy of a machine tool. Especially, high-speed spindle's thermal error restricts the improvement of high-precision machine tool accuracy. In this paper, the traditional back propagation (BP) neural network modeling principle is firstly analyzed. Then, considering the BP network, which is simple and adaptive but converges slowly and is easy to reach local minima, a genetic algorithm (GA) is introduced to optimize BP network's initial weights and thresholds. Lastly, the network is trained using combined GA and BP technologies with practical thermal error sample data. In experiments of thermal error prediction of the high-speed spindle in a machine tool, the average compensation rate is increased from 89.03 % of BP model to 93.155 % of GABP model. Therefore, GABP model shows its effectiveness in quickly solving the global minimum searching problem. © 2014 Springer-Verlag London.

Jiang S.Z.,Tianjin Sino German Vocational Technical College | Yan W.B.,Tianjin University of Technology and Education
Advanced Materials Research | Year: 2014

Taking the block of a diesel engine as example, the entity's geometric model is constructed according to reasonable simplification of design. Research was made on the effects of the FEM modal analysis results with different meshing densities. The results provide reference for the choice of element in further engine modal analysis. The results also provide basis for further structure dynamic analysis and control of noise of the diesel engine. © (2014) Trans Tech Publications, Switzerland.

Zhang J.,Tianjin University of Technology and Education | Zhang X.,TianJin Sino German Vocational Technical College
Applied Mechanics and Materials | Year: 2013

The micro inertial sensor parts (gyroscope and accelerometer) measurement error is the main factors to influence the accuracy of the inertial navigation system, in order to improve the navigation precision of SINS (strap-down inertial navigation system), we must reduce inertial sensor measurement error. Based on the error analysis of the inertial measurement device, with accelerometer attitude computation information as gyro attitude computation information reference quantity, established the algorithm of the attitude angle. In the sensor output signal pretreatment technology, this paper mainly introduced the use of surface fitting technology, to establish the error compensation surface equation, and gives the mathematical derivation of calculation error model parameter, the experiment got a good compensation effect. © (2013) Trans Tech Publications, Switzerland.

Zhang L.,Tianjin University | Zhang L.,Tianjin Sino German Vocational Technical College | Zhang Y.-F.,Tianjin University
Energies | Year: 2014

Research results have identified the use of heat pipe heat exchangers (HPHXs) for heat recovery as a way to reduce the pre-cooling and re-heating energy. This paper suggests decoupling dehumidification from cooling to reduce energy consumption. The feasible usage and the energy saving potential of heat pipe heat exchanger at the air handler dedicated in accomplishing this objective is investigated. In this paper a dedicated ventilation system combined with a HPHX to reduce energy consumption is tested and investigated under varying conditions by laboratory experiments. The energy saving potential and heat pipe (HP) effectiveness are tested and calculated under various outdoor conditions. The simulation and experimental results demonstrate that for all cases examined, the average HP effectiveness and energy savings have the same trend at various outdoor temperatures and Relative Humidity (RH) values. It has been found that the heat pipe can be applied to save over 60% energy for the air-conditioning operating hours. The reduction in overall energy is from 1.8% to 2.8% for the whole system. Therefore, the results confirm that the proposed set-up is useful for buildings to achieve intended energy saving objectives in subtropical climates where air-conditioning demand is highly variable. © 2014 by the authors.

Zhang X.H.,Tianjin Sino German Vocational Technical College | Zhang J.X.,Tianjin Sino German Vocational Technical College
Advanced Materials Research | Year: 2014

Construction machinery hydraulic cylinder is usually discarded after service cycle. The residual value of discarded products can be recycled greatly by remanufacturing. Disassembly and assembly is the key process in hydraulic cylinder remanufacturing. The construction machinery hydraulic cylinder disassembly and assembly equipment is developed. Hydraulic power is adopted in this equipment. The clamping, positioning of cylinder tube is realized by hydraulic clamping mechanism automatically. The piston component pulling out or into cylinder tube is realized by hydraulic working mechanism automatically. This equipment has been applied successfully in the project of key technology and equipment for construction machinery parts remanufacturing in a research institute. The results indicate that the application of this equipment will not only increase the automaticity and efficiency remarkably, but also reduce the damage to hydraulic cylinder key part greatly. © (2014) Trans Tech Publications, Switzerland.

Wu J.,Tianjin Sino German Vocational Technical College
Applied Mechanics and Materials | Year: 2013

Dual phase (DP) steel is a high strength steel for auto-panel. In this paper, mechanical property, forming ability of high strength steel DP450 are studied by experiments and compared with those of steel MS6000. And theoretical research on predicting the forming limit of steel DP450 by the NADDRG model. The established mathematic model for relativity is of practical usefulness. Experimental results reveal that the yield strength of steel DP450 is about 7.2% lower than the MS6000, and the break strength increases by 18.9%, while the elongation increases by 19%. The results show that mechanical property of high strength steel DP450 is better than that of MS6000, while forming ability of DP450 is not lower than that of MS6000. © (2013) Trans Tech Publications, Switzerland.

Tian J.Y.,Tianjin Sino German Vocational Technical College | Ying Z.,China TianChen Engineering Corporation
Applied Mechanics and Materials | Year: 2014

In this paper, the pressure vessel of a project is mentioned, the key technique of multilayer-wrapped type cylinder system and inspection technology are discussed. This paper analyzed the main manufacturing difficulties, which can provide reference for similar products. © (2014) Trans Tech Publications, Switzerland. All Rights Reserved.

Du H.,Tianjin Sino German Vocational Technical College | Du D.,Tianjin Sino German Vocational Technical College
MATEC Web of Conferences | Year: 2016

Conventional gasoline engine with an umbrella valve control cylinder intake and exhaust, in order to achieve sealing effect, the valve is driven by the spring force; at the same time, when the cam opens the valve to overcome the spring force acting. Sealing the better, the more power consumed in the engine mechanical losses, the valve mechanism consumes about 30%, which is not a small loss! This article describes a new type of rotary valve is to significantly reduce mechanical losses, so as to achieve energy saving purposes. © 2016 The Authors, published by EDP Sciences.

Qiu M.Y.,Tianjin Sino German Vocational Technical College
Applied Mechanics and Materials | Year: 2014

Nanosized ZnO thin films were prepared both on Si(111) and alumina substrates by the method of DC magnetron sputtering. Annealing was carried out, at different temperature respectively. The structure of unannealed and annealed thin films were studied by XRD, the infection of annealing temperature on sensing properties of ZnO thin films was analysed. After 700°C annealing the sample showed excellent selectivity and highest sensitivity towards acetone, and the response and recover time were short, the best working temperature was 220°C. ZnO is an important sensitive semiconductor gas material, it belongs to surface-controlled gas sensors, which has been developed as early as in the 60s. Compare to another two series of metal oxide gas sensing materials SnO2 and Fe2O3, ZnO is more stable. But its sensitivity is lower and its working temperature is higher, moreover, its selectivity isn’t good[1]. Therefore, the improvement of ZnO gas sensitive materials mainly focuses on raising sensitivity, improving selectivity, lowering temperature and other aspects of the work. ZnO films have a certain potential market and good industrical prospect. At present, these methods that have been reported such as precious metals, rare earth doped oxide composite doped, surface modification have achieved good progress[2∼5]. Our laboratory prepared ZnO thin films by DC magnetron sputtering, and annealed at different temperatures. The result showed that ZnO thin films have excellent selectivity and high sensitivity to acetone after annealed of 700°C. Besides the response and recover time were very short, its best working temperature was 220°C. © (2014) Trans Tech Publications, Switzerland.

Xu Z.,Tianjin Sino German Vocational Technical College | Fuqiang Q.,Tianjin Sino German Vocational Technical College
Proceedings - 13th International Symposium on Distributed Computing and Applications to Business, Engineering and Science, DCABES 2014 | Year: 2014

Aiming at the long response time, inaccurate recommendation and cold-start problems that faced by present recommendation algorithm, this paper, taking movie recommendation system as an example, proposes a collaborative filtering recommendation model based on user's credibility clustering. This model divides recommendation process into offline and online phases. Offline, it uses the result of user's credibility for clustering and then writes the clustered information into a table in database. Online, finds the cluster that target user belongs to and then gives recommendation. As a whole, the model reduces the response time, improves the accuracy of the recommendation rate, and solves the new user's cold-start problem. © 2014 IEEE.

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