Advanced Materials Research Vols. 217-218

Abstract: Fracture toughness is one of the important parameters to characterize the general mechanical properties of materials, Tests for determining are usually performed on a fatigue test machine. However, for some large structure parts, such as hydropower generator rotor, weighing several tons or even one hundred tons, it requires large samples for testing, which results in the large loss of the materials.. In the present work, we use a small sample to measure its , and the consistency of and on characterizing fracture toughness of small size samples was analyzed. Both the experimental results and theoretical calculations show that, under certain experimental conditions, can replace to characterize the fracture toughness.

Abstract: The effect of draw ratio and take-up velocity on the structure and property of the ultra-fine denier PET full drawing yarn (PET-FDY) with monofilament linear density equal to 0.38dTex was studied in this paper. The crystalline structure and crystalline size were determined by XRD method and size was reduced with increase of draw ratio. The orientation of whole molecular chain was determined using sonic velocity method. The mechanical properties and boiling water shrinkage were also examined. Draw ratio had greater influence on the boiling water shrinkage than take-up velocity did.

Abstract: The probability that the starting points or ending points of time intervals of two random events are equal is zero. Hence, in order to improve the efficiency of temporal reasoning, We introduced Heisenberg’s uncertainty principle to delete the fifteen basic temporal relations that the probabilities they happen were zero from INDU temporal system. The other ten basic temporal relations that the probabilities they happen were greater than zero were reserved. We used the characteristic sets to represent the ten basic temporal relations and got a fuzzy temporal system--UINDU. We gave the composition table of UINDU. It simplified INDU greatly. The experiments showed that the efficiency of UINDU was better than INDU.

Abstract: The finite element calculation model of the cement-soil pile composite foundation based on asymptotic homogenization theory has been built, under the state of three-dimensional stress, the equivalent elastic parameter of the composite elastic foundation model has been calculated, and depending on which, the settlement quantity has been calculated. Analysis through comparison with the testing result shows that it is feasible to use the homogenization method for calculating the settlement quantity of the composite elastic foundation, which sets up a theoretical basis for further analysis of homogenization method about composite foundation.

Abstract: As the precondition of fingerprint identification, the effective image segmentation plays the significant role in the following image processing. Unlike other images, the fingerprint images are obviously directional. Aiming at this feature, in this paper, an image segmentation method based on the directional information of fingerprint image is introduced, which sufficiently utilizes the directional information of fingerprint image and succeeds in separating the background information. However, owing to the absence of directional information in some local areas of fingerprint image, this method will produce large segmentation errors, even fail. Therefore, for these local regions without directional information, it is proposed to apply Bayesian decision-making theory based on minimum error probability to realize image segmentation. On the assumption that the gray values accord with the probability distribution of Gaussian finite mixture model in image feature space, EM algorithm is used to estimate the parameters of mixture model. The mixture application of two methods can effectively separate the background information from fingerprint image while saving the preprocessing time and ensuring the following identification accuracy of fingerprint. The experiments illustrate the feasibility of the hybrid approach.

Abstract: This document explains and demonstrates a new means of dynamic and static bending evaluation of modulus of elasticity for small samples of thin wood composites. This means is based on the principle of cantilever-beam bending and free vibration, and a cantilever beam testing apparatus has been developed according to this principle. Three kinds of thin particleboard obtained from market were processed and tested. The testing results show that there are significant linear correlations between the cantilever dynamic modulus and the static bending modulus. Through this method, it is feasible to measure the modulus of elasticity for thin wood composites, and compared with traditional method, the static bending test; it can save more time and reduce damage.

Abstract: During maintenance of ancient timber architectures, it is important to determine mechanical properties of the wood component materials non-destructively and effectively, so that degraded members may be replaced or repaired to avoid structural failure. Experimental materials are four larch (Larix principis-rupprechtii Mayr.) components, which were taken down from the drum-tower of Zhengjue Temple of Yuanmingyuan (Old Summer Palace), Beijing, China. The larch components were cut into standard specimens first, and then stress wave transmission times, resistograph and densities were tested. Product of resitograph and stress wave speed squared is defined as modulus of stress-resistograph. Comparing with the modulus of elasticity (MOE) of the specimens tested by the traditional bending test method, it is found that there is a linear relationships between the modulus of stress-resistograph and modulus of elasticity (MOE), and the correlation coefficients are 0.7111. In order to better evaluate the modulus of elasticity (MOE) with the modulus of stress-resistograph, 95% confidence regression lines are suggested to be used for the future calculation.

Abstract: Considering the actuality of current speech recognition and the characteristic of RBF neural network, a noise-robust speech recognition system based on RBF neural network is proposed with the entire-supervised algorithm. If the traditional clustering algorithm is employed, there is a flaw that the node center of hidden layer is always sensitive to the initial value, but if the entire-supervised algorithm is used, the flaw will not turn up, and the classification ability of RBF network will be enhanced. Experimental results show that, compared with the traditional clustering algorithm, the entire-supervised algorithm is of higher recognition rate in different SNRs than that of clustering algorithm.

Abstract: In this paper, the nonlinearity parameter B/A of ethanol has been measured under different emitted voltages, temperatures, multiple frequencies and stop-band attenuations. The experimental apparatus and technique used to measure B/A in ethanol was the finite amplitude insert-substitution method. This method was applied within the emitted voltages from 30.0 to 150.0V and at temperatures of between 22 and 45°C, and different frequencies at 1.0MHz, 2.25MHz, 3.5MHz, 5.0MHz and in attenuations from 30.0 to 120dB. Experimental results (Fig.4, Fig.5, Fig.6, Fig.7) show that: (1) The value of B/A has almost a linear increase with temperature and a linear decrease with frequency. (2) Parameter B/A is independent of the stop-band attenuations and has a little decrease with different emitted voltage.

Abstract: Modeled nonlinearity, time-varying, dynamic coupling finite element model of scraper conveyor according to its actual working condition in the mining, studied the transmission mechanism of bulk material power and its parameters test methods，constructed the shape function of scraper conveyor circuitry, realized the computer automatic modeling, by the example carried on digital simulation of all of working condition such as starting, freely stoppage, abnormal load, chains blocked, the difference of chain’s pitch and the chain wheel polygon effect, and so on.