800 publications from this institution
Through analyzing the mechanism of lubricating oil film on the rotating components,the new requirements of oil film structure was presented,on the basis of these requirements the structure of closed oil tank were presented,which difference from the traditional forms.The tooling process of the closed was designed through analyzing its processing,and then the full-closed oil tank was processed by the tooling process.Practice shows that these can improve the characteristics of lubricating in the rotary parts,reduce the wear and heat in the rotary parts,and improve transmission efficiency and simplify the way of lubrication.
Frequent occurrences of meteorological disasters (MD) in recent years have revealed the deficiencies of traditional transmission network planning (TNP) methods, which fail to establish mathematical relationship between the MD and the transmission line outage rate (TLOR) when calculating the vulnerability index of transmission network. As a result, the planning schemes are usually unable to determine the critical lines that should be guaranteed in the event of MDs, which is against the basic principles of economy and reliability. In this paper, a differentiation based method to TNP is proposed to optimize the fortification standard levels of different transmission lines for improving the anti-disaster ability. A three-state meteorological model is firstly developed to evaluate the effect of MD on TLOR; then a multi-objective TNP model is built considering economy and vulnerability objectives. Results show the TNP method can determine the fortification standard level of each transmission line for improving the anti-disaster ability while minimize the construction cost as much as possible, which is of significant reference value to the TNP under the meteorological disaster-prone environment.
By analyzing thermal energy utilization and evaluating waste heat resource in fiber board production process,this paper explored the prospect and the approach of reusing waste heat and searched new way for upgrading energy using in fiber board industry.
Compared with NPC converters, Active NPC (ANPC) converters improve the loss distribution among semiconductor devices and thus increase the converter output power rating and switching frequency. However, since more switches with their gate drivers are used in ANPC converters, the impact on the converter reliability is one of the main concerns for drives application. In this paper, the analysis on fault tolerant operation of 3L-ANPC converters under single and multiple device failure conditions is presented. Furthermore, the methodology for reliability function calculation and the reliability comparison of 3L-ANPC and 3L-NPC converters are investigated for drives application. Finally, the results and conclusions are presented.
The prevention and treatment of water hammer should be paid special attention to in long-distance water pipes with pressure.In this paper,it is introduced the successful study and applications on preventive measures for water hammer in ore pulp pipes and water pipes projects of Baiyunebo West Mine,which provide the direction for prevention and treatment of water hammer in other long-distance water pipes in future.
Concept and basic principle of static process contro(lSPC)and their application in etching process in the microcircuit fabrication are introduced.The difference between hidden exponents of the processing ability and actual exponents of the processing ability and the normal calculation method of the bilateral specification are all presented in detail.Meanwhile,the judgment regulations of exponents of the processing ability during the actual processing are given.Usage of SPC in monitoring the machine working status during etching process and its application of the content and the style in the main process are all studied.How to establish SPC controlgraph,how to collect the parameters,how to choose the graph and how to evaluate the process capability are all discussed here.Furthermore,the analysis methods of abnormity points which appeared during etching process are illustrated by showing an example.
Cable is one of the importantpartsin the cable-stayed bridges. It' s the spring-bearing of the continuous girder,the place of which strongly influences the state of the girder,therefore,its construction control of the cable anchortube(CAT) isvery important.Forthe construction control of CAT of Xiantao Hanjiang River Highway Bridge,its technological process—— the making,the setting,the checking of CAT is introduced and positive suggestions are made,which can push the construction of the cable-stayed bridge forward.
Vehicles equipped with various types of sensors have the great potentials to effectively evaluate the health conditions of a population of bridges at a low cost. However, existing drive-by structural health monitoring (SHM) methods acquire vehicle vibration responses offline and export them to a computer for postprocessing. Furthermore, the vehicle trajectory information on the bridge is important for scaling up the drive-by SHM for in situ applications, which is not synchronously measured by existing systems. Therefore, a single-board computer-based IoT sensing system for continuous and real-time drive-by bridge health monitoring is developed in this study. The developed IoT sensing system integrates a triaxial microelectromechanical system (MEMS) accelerometer, temperature sensor, GPS and 4G module on Raspberry Pi 4 Model B. The sensor node can be mounted on a moving vehicle to collect the triaxial acceleration responses, temperature and GPS information. A graphical user interface (GUI) is developed based on the Python Tkinter package to remotely control the sensor node and visualise the collected data in real time. The fast Fourier transform of the measured acceleration responses is performed on the sensor node inboard processor. The raw data are sent to both the cloud server and remote terminal computer through a 4G module. The goal is to provide a low-cost, accurate and scalable sensing system for easy implementation of drive-by bridge health monitoring. The system architecture and workflow of the developed IoT sensing system are presented in detail. A series of experimental tests are conducted to validate the accuracy of the measured acceleration responses and feasibility of using the developed IoT sensing system for drive-by SHM applications.
According to request of test pattern for flameproof electrical equipment shell,for more and more flameproof rectangular tank,by simplified analysis of the tank,made a design and calculation method of strength of wall,flange and bolts in tank.
Cable anchorages are among the most important elements in a cable-stayed bridge, which are complex in structure and bear heavy load. There are three main forms in anchorage zone between girder and cable in modern long-span cable-stayed bridge with steel box girder, which are ear-plate form, anchor-box form and anchor-plate form. Combining theoretical analysis with the static test, static behavior and stress transfer pathway of three typical cable-to-girder anchorages were analyzed, and the differences of stress distribution and stress concentration among anchorage zones were pointed out. Based on the Von.Mises strength criterion, bearing safety of three typical cable-to-girder anchorages was evaluated. Finally, the measures to reform stress distribution and reduce stress concentration are discussed. Some useful conclusions were obtained, which would benefit the design of cable-to-girder anchorages.
This paper introduces a new concept for offshore wind turbine electrical architectures for wind farms with MVDC collection grids. With the proposed pre-transformer wind turbine drivetrain arrangement, the AC output of the wind turbine generator is transformed to a higher voltage by a step-up transformer and then rectified to a corresponding DC voltage by an active ac-dc converter. A modular multilevel converter (MMC) is used for the rectifier to achieve the variable frequency AC to DC power conversion. The MMC has been shown to have burdensome design constraints at low frequency. This paper demonstrates that these design constraints are not applicable for the wind turbine application and that the MMC is a good candidate for the wind turbine rectifier.
