Search results

The primary mission of this design is the air conditioning design of a hotel in Guangzhou city. The calculation of cooling load & heat load, division of the air conditioning system and the determination of the scheme, the design of the duct and water system, and the design of the smoke prevention and extraction system are all included. According to the related standard and considering the energy saving and comfort requirements, the air conditioning system are determined through the economic and technological comparison. Primary return air system is used for open office area and dining hall; fan-coil units with fresh air system is adopted for the guest rooms of the hotel; and the VRV system is adopted for the large conference room. The new air in restaurant rooms and the large conference room is handled by full-heat type fresh air exchanger; new air in guest room is handled by air conditioning units.

After the Japan nuclear power crisis in 2011, main nuclear power countries and international organizations reactions to nuclear emergency and security problem had become a hot topic. The global concern on power emergency problem after the Japan Fukushima nuclear crisis was reviewed comprehensively. The International Atomic Energy Agency (IAEA) investigation, the U. S. NRC Security Check, EU stress test, and France ASN complementary safety assessment results were stated in detail. As an important source of power, China’s altitude toward the sustainable nuclear power development and safety was also surveyed. The main nuclear power countries all claimed their position to insist on the development of nuclear power while taking lessons from Japan Fukushima nuclear crisis. Finally some comments and suggestions to improve China’s power industry emergency response and drills system to support the sustainable development of nuclear energy were proposed.

A novel image segmentation algorithm based on fuzzy C-means (FCM) clustering and improved particle swarm optimization (PSO) is proposed. The algorithm takes global search results of improved PSO as the initialized values of the FCM, effectively avoiding easily trapping into local optimum of the traditional FCM and the premature convergence of PSO. Meanwhile, the algorithm takes the clustering centers as the reference to search scope of improved PSO algorithm for global searching that are obtained through hard C-means (HCM) algorithm for improving the velocity of the algorithm. The experimental results show the proposed algorithm can converge more quickly and segment the image more effectively than the traditional FCM algorithm.

We introduce the differential evolution (DE) algorithm in the geophysical nonlinear inversion field. We set up a nonlinear inversion model of DC electrical sounding data using the DE algorithm. A comparison between the model and actual data suggests that the DE algorithm is more accurate and faster than existing algorithms. The study results presumably open new vistas in geophysical nonlinear inversion, and the DE algorithm may find application in two-dimensional or three-dimensional electrical sounding inversion. In the end, we applied the DE algorithm to the polymetallic ore exploration successfully in Inner Mongolia.

In recent years, the rapid growth of the air conditioning load has become the most important reason of the seasonal power shortage. It has great significance to adjust the air conditioning load for changing the load curve of commercial users and realizing the power grid load shifting. In order to achieve the optimal allocation of resources and improve efficiency of using electricity that make the central air conditioning run efficiently, it needs to study the key technologies of load regulation and management of energy efficiency about the central air-conditioning.

The response surface method (RSM) is widely used to alleviate the computational burden of engineering analyses. For reliability analysis, the common approach in the RSM is to use a linear interpolation technique. However, the experimental points are all arranged using the classical RSM in each process of interpolation. Therefore, the number of experimental points is large that resulting in the efficiency is lower. In this study, an improvement of the RSM for structural reliability analysis has been proposed based on the technique of successive linear interpolation. As seen from the example, the proposed method yields better results than those of the classical RSM, and the number of experimental points using the proposed method is less than that of classical RSM. It seems that the proposed method improves the convergence speed and reduces the computational effort.

The material constants calculation models for hyperbolic-sine creep model were proposed. The material constants used in hyperbolic-sine creep model for 316 stainless steel were calculated due to the models proposed and experimental data in the temperature range from 873K to 1023K. The relationships between material constants of 316 stainless steel creep model and temperature were obtained by curve fitting. The creep rate predict model of 316 stainless steel with only stress and temperature was also developed, the creep rates predicted were in good agreement with experimental data.

A 7-DOF half-car dynamic model which includes the cab mounting system and seat suspension system was established to study the performance of active seat suspension. The optimal control method was applied to design the active control system. Two dynamic simulation models of the passive seat suspension and the active seat suspension were set up by Matlab/Simulink, and the performance of the passive and active seat system was simulated in the time and frequency domain. The simulation results show that the active seat suspension can greatly improve the vehicle seat performance and the study has supplied the academic reference in the applications of the active seat suspension.

Hard and brittle materials such as WC, SiC, and single crystal silicon or germanium are widely used in die/moulds for very high accuracy glass products, medical devices, and sensors for MEMS. Mechanical ductile-mode micro/nano milling is an effective method to create three dimensional geometries on these materials. One of the key factors affecting successfully ductile-mode machining is micro tooling. Due to limitations of commercially available micro tools, custom micro tooling is brought forward to give an active solution to this issue. This paper is a further study on custom micro tooling by the author, and several aspects associated with custom micro tooling have been discussed. Experimental results show the feasibility and effectiveness of the successful ductile-mode machining of hard and brittle materials by custom micro tooling. At last, this paper summarizes the techniques associated with custom micro tooling and point out the key aspects for further research on custom micro tooling.

To get an effective way of monitoring the diesel engine vibration signal, the author puts forward an optimized method based on rough set attribute dependency. Decision table formed by different data collection form, their decision attribute dependence of condition is different, by comparing the different points of attribute dependence and take it as the quality criteria of measuring points, we can realize the optimization of measuring points. Take a high power diesel engine as an example, the site of rough set theory are used to calculate the typical attribute dependence, the results show that the method can effectively distinguish between different measuring point position and the sensitive degree of different fault types, the vibration signal monitoring position, with better effect is obtained at the same time reducing the effects of noise on fault diagnosis, to improve the accuracy and efficiency of fault diagnosis.