Hangzhou Vocational and Technical College

Hangzhou, China

Hangzhou Vocational and Technical College

Hangzhou, China

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Tong Y.,Hangzhou Vocational and Technical College | Cho H.,Chosun University
International Journal of Air-Conditioning and Refrigeration | Year: 2015

Evacuated solar collectors with U-tubes (ESCU) and heat pipes (ESCHP) were designed and constructed to allow heat from solar radiation to be collected at a relatively high efficiency. A theoretical investigation of the overall performance of solar collectors under local weather conditions in Korea was carried out for two kinds of solar collectors: those with U-tubes and those with heat pipes. The results of the two models were then compared to those of the collector model to investigate their performance differences, which were affected by radiation, ambient temperature absorber areas, and structures. The comparisons showed high accordance between the simulation and experimental results for both types of solar collectors. The results obtained from the simplified model show that each type of collector had advantages. They had great efficiency disparities when the heat pipe-type had an 8% higher efficiency than the U-tube-type during the sunny day, while the U-tube-type showed steadier and better thermal performance when it was cloudy. © 2015 World Scientific Publishing Company.

Lou X.,Hangzhou Vocational and Technical College | Wu G.,Nantong University
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2012

The active magnetic bearing system is a complex nonlinear system and the system parameters often change with time. In this paper, the adaptive control and sliding mode control are combined to establish an adaptive sliding mode controller (ASMC) which is applied to a single degree of freedom magnetic bearing controlling system. With the system parameters changing the real-time control system can change the corresponding control parameters to make the system performance always maintain the optimal or nearly optimal. The simulation model of the single degree of freedom magnetic bearing based on ASMC and an experimental platform using PC as upper computer and TMS320F2812 as hypogyny are established. The simulation and experimental results show that the ASMS not only weaken the inherent chattering in the sliding mode control, but also has better robustness and rapidity. It can meet the real-time control requirements of the magnetic bearing system.

Tong Y.,Hangzhou Vocational and Technical College | Kim J.,Chosun University | Cho H.,Chosun University
Renewable Energy | Year: 2015

An enclosed-type evacuated U-tube solar collector (EEUSC) with high efficiency and low cost was designed and constructed. A copper fin was employed in the U-tube to assume a constant heat flux. The thermal performance of the EEUSC was evaluated under a wide range of operating conditions. Moreover, to increase the heat transfer efficiency in the U-tube over the thermal resistance of the air gap, a novel method was developed, which entailed filling the gap with high-thermal-conductivity liquid. Multi-walled carbon nanotube (MWCNT) nanofluid was used as the working fluid. Evaluation results showed that the efficiency of the EEUSC is influenced primarily by the air gap and that it increases by 4% with the use of the MWCNT nanoliquid. Calculations based on this improvement revealed that the annual CO2 and SO2 emissions will reduce by 1600kg and 5.3kg, respectively, when 50 solar collectors are employed. © 2015 Elsevier Ltd.

Chen X.,Hangzhou Vocational and Technical College
Communications in Computer and Information Science | Year: 2012

With the rapid development of e-commerce and the explosive growth of the information on Internet, the demands of recommendation system is being more and more urgent. In the past decades years, the research and application of recommendation system has been made considerable progress both in academia and industry. However, there are still a number of same problems that need to be improved constantly, such as sparse problems, cold-start problem etc. In this article, we design a multi-mode e-commerce recommendation system. By means of collecting a wide range of user's information, combined with a variety of recommendation algorithms which can learn from each other and finally comprehensively integrate all information into an overall result to provide users goods of service recommendations more accurately and comprehensively. © 2012 Springer-Verlag Berlin Heidelberg.

Wang Y.,Hangzhou Vocational and Technical College
Energy Education Science and Technology Part A: Energy Science and Research | Year: 2014

With the rapid popularity of the Internet for digital media bringing the rising of network literature, the new born network literature, text messaging literary through mobile phones and other new media had become the new art Chinese literary works in the new century. They were not only to be an unstoppable momentum of development with the traditional printing literature and writing, and changed the overall pattern of Chinese literature development, but also with the sharp idea of the media, constantly impacted traditional literary concept and production system, led to a historic transformation of Chinese literature. While facing such situation of literary development, how to regulate and lead the sound and rapid development could be significant to our society. Digital media literature on Chinese literature in the new century construction and prosperity would absorb the particularly important and urgent. Does the exist contemporary Chinese Literature creative? The solution working out awakened us to be confidence keen care, and sticked on the core principle, and made the peaceful transformation. © Sila Science. All Rights Reserved.

Jiang P.,Hangzhou Vocational and Technical College
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2014

The apoptotic responses induced by low dose nodularin on isolated macrophages from Carassius auratus were explored. Flow cytometric results showed that nodularin-treated macrophages had sub-G1 DNA peaks. Nodularin could block cells in G0/G1 and S phase and disturb cell cycle. The percentages of apoptotic cells incubated with 1, 10 and 100 μg·L-1 nodularin for 12 h reached 17.37%, 27.59% and 61.64%, respectively, while controls showed low rates of apoptosis (3.72%). The concentrations of intracellular Ca2+ for 100 μg·L-1 exposure group increased by 76.9% in comparison with the control group, while the mitochondrial transmembrane potential (MMP) decreased by 35.8%. The doses of reactive oxygen species (ROS) and malondialdehyde (MDA) for 100 μg·L-1 exposure group were 1.86 and 2.94 times that of the control group. After 100 μg·L-1 nodularin exposed for 12 h, the activity of Caspase-3 and Caspase-9 were 2.89 and 3.73 times that of the control group, respectively. The activity of Caspase-8 in 100 μg·L-1 nodularin induced group increased by 33.3%, compared to the control group. All the biochemical apoptosis indicators analyzed in this study clearly showed dose-dependent manners. In summary, all the results suggested that nodularin could induce macrophages apoptosis via the mitochondrial apoptotic pathway and destroy the immune response of fish.

Li Y.,Hangzhou Vocational and Technical College
Applied Mechanics and Materials | Year: 2013

The gyroscopes have been used as a suitable inertial instrument for the navigation guidance and attitude controls. The accuracy as very sensitive sensor is limited by the lock-in region (dead band) due to the frequency coupling between two counter-propagating waves at low rotation rates. This frequency coupling gives no phase difference, and an angular increment is not detected. This problem can be overcome by mechanically dithering the gyroscope. This paper presents the design method of mechanical dither by the theoretical considerations and the verification of the theoretical equations through FEM applications. As a result, comparing to the past result, the maximum prediction error of resonant frequency was within 3 percent and peak dither rate was within 5 percent. It was found that the theoretical equations can be feasible for the mechanical performance of dither. © (2013) Trans Tech Publications, Switzerland.

Li Y.,Hangzhou Vocational and Technical College
Applied Mechanics and Materials | Year: 2013

The throughput of a mail piece sorting machine is limited by the mechanical capabilities of the machine, and also by the performance of the address reading device. In order to avoid unprocessed mail items leaving the machine, sophisticated throughput control is required. An appropriate control structure is presented here, which is applicable to a general class of transport processes. The approach is based on the classical ideas of time-optimal control and disturbance measurement and feedback. © (2013) Trans Tech Publications, Switzerland.

Zhao C.R.,Hangzhou Vocational and Technical College
Applied Mechanics and Materials | Year: 2013

There is a deep connection between machinery manufacturing theories and automated manufacturing modes. In a sense, automation technologies aim to meet the needs of mechanical manufacturing, and automated manufacturing modes have a broader range of applications. However, with the development of economy and technology, the mechanical devices themselves are more complex and sophisticated, and the traditional machinery manufacturing theories and automated manufacturing modes are difficult to meet the demands of production. In order to find a better solution, based on the concept of machinery manufacturing theories and automated manufacturing modes, this study analyzed the generated characteristics after the combination of the above two objects, such as integrated, market-oriented and intelligent, etc. © (2013) Trans Tech Publications, Switzerland.

Lou X.,Hangzhou Vocational and Technical College
Applied Mechanics and Materials | Year: 2012

In this paper, we have discussed the adaptive controller problem for a class of nonlinear discrete systems. Firstly, the general nonlinear discrete-time system is transformed into a new form which is more suitable for adaptive controller design. Based on the new model, the observer is proposed to estimate the unavailable states. The adaptive controller is designed to track the desired trajectory. © (2012) Trans Tech Publications, Switzerland.

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