Applied Mechanics and Materials Vols. 333-335

Abstract: Cluster methods can be used for fault diagnosis of marine diesel engine. We propose a cluster method by assigning a class label to each sample and updating it according to the class label probability. Due to the random walk process in cluster process, multiple results are obtained, and some classes can be found more easily. Fault diagnosis simulation experiment is executed on a self-manufactured marine engine room simulator to verify the method performance, and we obtain the correct graphical and number results. Both fault patterns in fault history and new fault pattern can be recognized.

Abstract: The key system which requiring very high levels of reliability often use redundancy to enhance reliability index, e.g. tolerant system. During system operation, tolerant system monitors system state and reconfigures it to realize continuous working with system drawback. Considering the inevitable errors in system online test and the performance degradation, an estimation method for both system reliability and performance is proposed in this paper. Through analyzing the important fault mode in tolerant system, establishing the system reliability model based on k-out-n:G system description, and then considering the imperfect tests and corresponding performance degradation in these process, the reliability and performance evaluation method is given, moreover, the engineering operation flow of this method was established for it. An aircrafts rudder system is taken as an example for engineering application, which shows that this approach is feasible and effective.

Abstract: In order to realize fast measurement of fabric defect dimensions, an image measuring method is presented for the fabric defect detection system. Based on the image measuring theory, a suitable structure of the system hardware is constructed by using common device used in the fabric defect detection system. A new CCD calibration method based on grid targets is applied to the system. The experimental results show that the method is effective, high accuracy and easy to implement.

Abstract: The system monitors seismic responses of isolated structure and non-isolated structure in WenChuan with earthquake, and compared with them. The system of seismic sensors collected seismic signals to the FPGA chip, and FPGA transmits the signal to the real-time controller through the internal bus after filtering. The real-time controller monitors signals and triggers the storage, at the same time the controller will transmit data to the host computer through the Ethernet, and the PC as the local server, which can be accessed real-time by remote computers. A plurality of acquisition station support multiple acquisition station synchronization acquisition using the GPS trigger synchronization.

Abstract: On the basis of a transmission error-testing laboratory bench which is designed in advance, the research and design of a transmission error-testing system of harmonic drive are carried on. The structural composition and test principle of this testing system are introduced. Based on the software, LabView2009, the design of the transmission error-testing system of harmonic drive is finished. With the help of this testing system, the following purposes can be realized. The input and output angle data of the harmonic drive can be acquired, its transmission error is capable of being analyzed and the data will be able to be stored.

Abstract: Lattice Discrete Particle Model (LDPM) provides accurate representation of concrete behavior under cycling loading both in tension and unconfined, confined, and hydrostatic compression. In this paper, LDPM is used to simulate tensile fracturing as demonstrated by the successful simulation of three points bending tests on notched specimens, the result show that it is able to reproduce pre-peak nonlinearity as well as softening post-peak behavior. It reproduces realistically the development of crack pattern due to tensile stresses and also could predict correctly size effect on specimen load carrying capacity.

Abstract: In this paper, a novel method fog determination of chemiluminescence (CL) spectra utilizing LS55 luminescence spectrophotometer was proposed. By this means, the CL spectra generated from the oxidation of cephalosporins with potassium permanganate was investigated. The result indicated that acid potassium permanganate CL system has more then three emitting species, excited state Mn(Ⅱ), Mn(Ⅲ) and singlet oxygen all could be assigned as the possible emitting species of this CL system. Base on above investigation results, sodium cefoperazone in pharmaceutical samples was determined by a CL analysis process combining with flow-injection technique. The detection limits estimated by a conservative model (3σ) of cefoperazone was 0.1µg dm^-3, and the maximum relative standard deviation (RSD) was not more than 0.8 % (n=11, ρ=20µg dm^-3).

Abstract: Electromagnetic microwave absorbing composite material containing magnetic Mn-Zn ferrite/conductive polyaniline nanocomposites introducing into epoxy resin were fabricated. The conductivity of the Mn-Zn ferrite/polyaniline nanocomposites were investigated by a four point probe method. Complex permeability and reflection loss of the Mn-Zn ferrite/conductive polyaniline/epoxy resin composites have been studied in the frequency of 30 MHz to 1 GHz. It has been found that the conductivity of the nanocomposites can be tailored by controlling the weight percentage of polyaniline. The complex permeability increased with the decreasing weight percent of polyaniline. The composite with the polyaniline weight percent of above 60.89 % can effectively broaden the absorbing band with minimum absorption of 5 dB about 500 MHz. It has also been found that the composite with the polyaniline weight percent of 28.12 % has a maximum absorption of 23 dB at about 700 MHz for a coating thickness of 2 mm. Therefore, the prepared composites can be potentially applied in electromagnetic absorbing field in the low frequency.

Abstract: Polystyrene microspheres were prepared by the emulsifier-free polymerization method. Using the polystyrene microspheres as seeds, 2,4-dichlorophenoxyacetic acid as template molecules, the monodispersed molecularly imprinted polymer microspheres (MIPMs) were prepared by a single-step swelling and polymerization method. The monodispersed molecular imprinted polymers with porous structure were characterized by SEM, and UV-visible spectrophotometry. The adsorption performance of MIPMs for 2,4-dichlorophenoxyacetic acid was investigated.

Abstract: This paper discussed the effect of Suizhong 36-1 oilfield reinjection sewage on core permeability in different suspending particle sizes, different concentration of suspended substances and different injection volume of water. The experimental results showed that: The larger the suspended particles diameter, the greater the concentration, the higher the injury rate; The lower the formation permeability, the greater the damage; The core permeability was markedly decreased with the increase of the volume of injected water; The formation damage degree was D11 > mixed injection > well water.