Zhang Y.-L.,Quzhou College
Reneng Dongli Gongcheng/Journal of Engineering for Thermal Energy and Power | Year: 2016
To reveal in-depth the transient response characteristics of a centrifugal pump when it has a drastic fluctuation of the rotating speed, set up was a circulating pipeline system, including a set of low specific speed centrifugal pump. According to the function defined by users themselves, sliding mesh method and RNG k-ε turbulent flow model, an unsteady flow self-coupling numerical calculation was performed of the whole system. It has been found that the flow rate response lags behind the rotating speed variation course while the head response features a relatively good nature to follow up the rotating speed variation. The interference between the rotor and stator inside the turbomachinery exercises a most notable influence on the pressure at the outlet of the pump in the stage of the rotating speed acceleration and the pressure at the inlet of the pump in the stage of the rotating speed deceleration, however, exerts a relatively small influence on the flow rate and the power needed by the impeller. The evolution of the transient flow field in the process of the fluctuation in the rotating speed totally lags behind the quasi-steady state calculation results. The forgoing can offer important reference for revealing the transient response characteristics of a centrifugal pump. © 2016, Harbin Research Institute. All right reserved.
Lv C.-Z.,Quzhou College
2011 International Conference on Electrical and Control Engineering, ICECE 2011 - Proceedings | Year: 2011
Ancient building protection conducted in different place was an effective method for the ancient building protection. There were abundant ancient buildings in Longyou city. The ancient building structures in Longyou city were surveyed by using the traditional method. Their level control points were surveyed by using fourth-order leveling. Their distances and angles were surveyed by using ordinary leveling survey. Their wall painting, texture and bedding plane construction technology were surveyed by using close photography. Their brick carving, stone carving and wood carving were surveyed by using 3-D laser scanning. All of these measures realized the ancient buildings protection in different place. A lot of real data were gained by the leveling surveying, control surveying and detail surveying applied to the ancient building in Longyou city. The data were deal with error analysis and the ancient building construction drawings were restored with computer aided design. The project could provide an engineering reference for other ancient building protection which conducted in different place. © 2011 IEEE.
Xie X.S.,Quzhou College
Advanced Materials Research | Year: 2011
Early shrinkage of concrete includes plastic shrinkage before the final setting, drying shrinkage during hardening process and autogenous shrinkage. Concrete drying shrinkage which is caused by evaporation is a major factor for the concrete volume change. By ring constrained test and free shrinkage CONCEN test, this paper studies the impact of polypropylene fibers on the shrinkage properties of concrete at the early age. The test shows that the polypropylene fibers can significantly reduce the early shrinkage of concrete, the best content of C30 concrete should be 0.9kg/m3. © (2011) Trans Tech Publications.
Yan C.,Quzhou College
World Transactions on Engineering and Technology Education | Year: 2014
Regional Chinese engineering colleges face a serious challenge in regard to English teaching, including teaching modes, faculty preparation, teaching resources, curriculum design and methods. This challenge needs to be urgently addressed and steps-mode classroom teaching is one of the possible solutions. Steps-mode research-oriented classroom teaching is focused on the student with the teacher acting as a guide in problem-based tasks. In order to enhance students' learning enthusiasm, initiative and creativity, this teaching mode puts great emphasis on the research process of questions and answers, which cultivates students' divergent thinking, and assists in self-regulated learning and passionate exploration. Due to a more meaningful and deeper involvement of teachers and students, and the application of new methods and tools, this mode has been helpful in improving English learning and teaching quality in engineering majors at local engineering colleges. © 2014 WIETE.
Junlong S.,Ludong University |
Changxia L.,Ludong University |
Jin T.,Quzhou College |
Baofu F.,Ludong University
Ceramics International | Year: 2012
TiC and Mo were introduced into B 4C-based ceramic nozzles, which were obtained by hot-press sintering. The effect of TiC content on mechanical properties and erosion behavior of B 4C-based ceramic nozzles were analyzed. XRD analysis showed that chemical reactions took place during the sintering process, which resulted in B 4C/Mo/TiB 2 ceramic nozzle with high density and improved mechanical properties compared with B 4C/Mo ceramic nozzle. The sintering temperature was decreased from 2150 °C for B 4C/Mo ceramic nozzle to 1950 °C for B 4C/Mo/TiB 2 ceramic nozzle. Results of erosion wear tests indicated that the hardness and toughness were the key factors influencing the erosion rate of B 4C/Mo/TiB 2 ceramic nozzle. Analysis of the eroded bore surfaces of B 4C/Mo/TiB 2 ceramic nozzle showed that the entry bore section exhibited a brittle fracture induced material removal process, and the center bore section showed plowing and polishing of material removal. Fracture and plowing of material removal occurred at the exit bore section. © 2012 Elsevier Ltd and Techna Group S.r.l.
Lv M.-L.,Quzhou College |
Lu Z.-M.,Zhejiang University
Information Technology Journal | Year: 2011
Perceptual hashing has been proved to be an effective solution for multimedia indexing, authentication or watermarking. Traditional perceptual hashing schemes are typical designed only for one purpose. This study presents a multipurpose image-hashing scheme based on Mean-Removed Vector Quantization (MRVQ) for both copyright protection and content authentication. The main idea is to perform MRVQ on the original image to yield two index tables, one for copyright protection and the other for content authentication. The original gray-level image is first divided into non-overlapping small blocks. The mean value for each block is calculated and quantized by the scalar quantizer to get a mean index and the quantized mean is removed from the image block to obtain the residual vector that is further quantized by the vector quantizer to obtain the residual index. All obtained mean indices constructed the mean index table and all obtained residual indices construct the residual index table. The obtained two index tables are then transformed into two intermediate binary images based on two different mapping functions, respectively. One mapping function is based on the variance of indices in a 3 ×3 neighborhood and the other mapping function is based on the number of indices larger than the mean of indices in a 3 ×3 neighborhood. Finally, the authentication mark and permuted copyright logo are respectively XOR-ed with the two intermediate binary images to obtain final authentication and protection fingerprints. Experimental results demonstrate the effectiveness of the proposed scheme. © 2011 Asian Network for Scientific Information..
Lv M.L.,Quzhou College |
Lu Z.-M.,Zhejiang University
Information Technology Journal | Year: 2011
This study presents a new multipurpose image hashing scheme based on Block Truncation Coding (BTC). Vector Quantization (VQ) and BTC are both block-based lossy image compression techniques for gray-level images, but BTC can maintain the mean and standard deviation after compression. In our scheme, the original gray-level image is first partitioned into non-overlapping small blocks. BTC is then performed on each block to yield two mean values, i.e., a lower mean and a higher mean, as well as a bit plane. The relationship between two mean values are utilized to generate the intermediate binary image for copyright protection, while the number of '1' s in the bit plane is compared with a threshold to generate the intermediate binary image for content authentication. Finally, the authentication mark and permuted copyright logo are respectively XOR-ed with the two intermediate binary images to obtain final authentication and protection fingerprints. Because BTC is a fast encoding scheme, our proposed method is therefore with lower complexity compared to VQ-based multipurpose image hashing schemes. Experimental results demonstrate the effectiveness and efficiency of the proposed scheme. © 2011 Asian Network for Scientific Information.
Feng L.,Quzhou College
Advanced Materials Research | Year: 2012
The Non-uniform rational B-spline (NURBS) is widely used in CAD/CAM/CNC. The NURBS interpolation is crucial for an advanced CNC system compatible with NURBS. Classic NURBS interpolation algorithms always do not well consider both the contour precision and feedrate smoothness. This paper proposes a NURBS interpolation algorithm based on the feedrate sensitive points identification. The feedrate sensitive points is found out according to the chord error which is relative to the feedrate passing this point. Furthermore, the feedrate profile is adaptively planned between two adjacent sensitive points according to the distance between them. The feedrate profile of the whole NURBS can be connected with these feedrate sections. A cubic NURBS curve is adopted to evaluate the interpolation algorithm. Simulation results show that the proposed interpolation algorithm is available with reference value for industrial application.
Hu W.,Quzhou College
Advanced Materials Research | Year: 2011
A new environment-friendly wall material- the unfired brick is produced by using clay, carbide slag, fly ash and cement as the main raw materials, and certain amount of chemical excitator. The primary mixing ratio is designed on the basis of its mechanical properties and durability. When adopting water curing under normal temperature and atmosphere pressure, the compressive strength, flexural strength and frost resistance of the unfired brick are measured. The results reveal that the optimum mixing ratio for unfired brick is: Carbide slag 30%, fly ash 30%, cement 25% and clay 15%. For the unfired brick formed by vibration with the optimum mixing ratio,the min. compressive strength of each brick is more than 10 MPa, the overall properties meet the requirement as specified in standard JC 239-2001"Fly Ash Brick". © (2011) Trans Tech Publications, Switzerland.
Chen X.-Y.,Quzhou College
2010 International Conference on Computer Design and Applications, ICCDA 2010 | Year: 2010
Conceptual design is an early stage of the whole mechatronics product development process, which involves the generation of solutions to satisfy the design requirements. Conceptual design includes three stages: functional design, principle conceptual design and structure conceptual design. And Functional design is the important part of product's conceptual design. It is a crucial issue how to help designers to find proper functions and their function structure to meet design requirements. This paper proposes a functional design methodology based on functional ontology in mechatronics product design, which can be used to design innovative mechatronics products. The design of a separator machine is given as an example, which demonstrates that the methodology is obviously useful. © 2010 IEEE.