查看更多>>摘要：Freeze concentration has great potential in treating wastewaters containing soluble pollutions. It is important for freeze concentration process to produce ice crystals with large size and high purity. In this work raw urines of 4660 - 7914 mg/L in COD, 512. 71 - 872. 41 mg/L in NH_3 - N and 22600 - 28800 μs/cm in e-lectric conductivity were studied. Urines were frozen by a digital refrigerated circulator bath. Ice crystals were purified by ice-water steep and vacuum filtration. The COD, NH_3 - N, and electric conductivity levels of the melted ices were measured to reflect ice crystal purity. Effects of coolant temperature, ice crystal shape, initial solution temperature, solution concentration, ice seeding, re-crystallization process and crystallization time on ice crystal purity were analyzed. The results show that an appropriate coolant temperature, suspended ice crystals, an initial solution temperature of about 6 ℃ , introduction of seed ice, addition of re-crystallization process, and crystallization time of less than 30 min are in favor of producing ice crystals with high purity. Under such conditions, more than 99 percent of inorganic salts, COD and NH_3 - N sources in raw urine could be removed.
查看更多>>摘要：In the past several years, support vector machines ( SVM) have achieved a huge success in many fields, especially in pattern recognition. But the standard SVM cannot deal with length-variable vectors, which is one severe obstacle for its applications to some important areas, such as speech recognition and part-of-speech tagging. The paper proposed a novel SVM with discriminative dynamic time alignment ( DDTA - SVM) to solve this problem. When training DDTA - SVM classifier, according to the category information of the training samples , different time alignment strategies were adopted to manipulate them in the kernel functions, which contributed to great improvement for training speed and generalization capability of the classifier. Since the alignment operator was embedded in kernel functions, the training algorithms of standard SVM were still compatible in DDTA -SVM. In order to increase the reliability of the classification, a new classification algorithm was suggested. The preliminary experimental results on Chinese confusable syllables speech classification task show that DDTA - SVM obtains faster convergence speed and better classification performance than dynamic time alignment kernel SVM ( DTAK - SVM). Moreover, DDTA - SVM also gives higher classification precision compared to the conventional HMM. This proves that the proposed method is effective, especially for confusable length - variable pattern classification tasks.
查看更多>>摘要：This paper presented a hybrid control scheme to vibration reduction of flexible spacecraft during rotational maneuver by using variable structure output feedback control (VSOFC) and piezoelectric materials. The control configuration included the attitude controller based on VSOFC method and vibration attenuator designed by constant-gain negative velocity feedback control. The attitude controller consisted of a linear feedback term and a discontinuous feedback term. With the presence of this attitude controller, an additional flexible control system acting on the flexible parts can be designed for vibration control. Compared with conventional proportional-derivative (PD) control, the developed control scheme guarantees not only the stability of the closed-loop system, but also yields better performance and robustness in the presence of parametric uncertainties and external disturbance. Simulation results are presented for the spacecraft model to show the effectiveness of the proposed control techniques.
查看更多>>摘要：Controlling the thermal deformation is a crucial index for the design of the satellite antenna. To calculate and measure the satellite antenna' s thermal deformation is also an important step for the design of satellite antenna. Based on the foundation of equivalent assumption, the thermal deformation of the parabolic satellite antenna was analyzed by the finite element method for different design project. The best design project that had the minimum of the thermal deformation could be obtained through changing the lay-angle, lay-layers and lay-thickness of each layer. Results show the asymmetry structure has the minimum of thermal deformation. This paper may provide useful information for the further investigation on the coupling of thermal-stress structure.
查看更多>>摘要：In anti-seismic calculation, the mode truncation is a significant problem to engineers if the mode-superposition response spectrum method is used, which has not been completely solved yet in some large and complex structures such as reticulated domes. In this case, some useful advices, concentrating on the problem a-bove, are expected through a careful and comprehensive investigation of this paper. During the investigation, the authors first point out shortcomings of former researches. Then frequency-spectrum characteristics of single-layered reticulated domes were studied from the perspective of structural responses. During this process, some important results such as the existence of the main resonant section, and the fact that the relative sensitivity of these domes under horizontal and vertical impulse varies with the different R/S ratios were achieved. Furthermore , based on the study of frequency-spectrum characteristics, as well as that of earthquake input, reasonable numbers of mode truncation in single layered reticulated domes with different R/S ratio were presented. Results of case studies prove the mode truncation number proposed is valid.
查看更多>>摘要：For ceramic filtering materials, their adsorption capacities, purification efficiencies to remove organic compounds from drinking water, and correlation between adsorption capacities and pore structures were tested and analyzed. The results show that correlation coefficient between the specific surface area and the adsorptive amount of iodine molecule is 0. 99; correlation coefficient between the pore volume and the adsorptive value of tannin molecule is 0. 92, and correlation coefficient between the most probable diameter and the adsorption parameter is 1. 0. A new method of morphology characterization for ceramic filtering materials was developed, which offered a sort of standard for the evaluation on water purification efficiencies and selection of ceramic filtering materials.
TAI Li-gangGUO Hai-yingZHONG Ting-xiuLI Dian-qi...
623-628页
查看更多>>摘要：Knowledge acquisition has always been the bottleneck of artificial intelligence. It is the critical point in product family design. Here a knowledge acquisition method was introduced based on scenario model and repository grid and attribute ordering table technology. This method acquired knowledge through providing product design cases to expert, and recording the means and knowledge used by the expert to describe and resolve problems. It used object to express design entity, used scenario to describe the design process, used Event-Condition-Action(ECA) rule to drive design process, and with the help of repository grid and attribute ordering table technology to acquire design knowledge. It' s a good way to capture explicit and implicit knowledge. And its validity is proved with respective examples.
查看更多>>摘要：Decentralized and unstructured peer-to-peer applications such as Gnutella are attractive because they require no centralized directories and no precise control over network topology or data placement. Search algorithm is the major component of the distributed system and its efficiency also does influence the systems performance. However the flooding-based query algorithm used in Gnutella produces huge traffic and does not scale well. Gnutella-like P2P topology has power-law characteristic, so a search algorithm was proposed based on high degree nodes of power-law network, High Degree Nodes-Based Search ( HDNBS). Extensive simulation results show that this algorithm performs on power-law networks very well, achieves almost 100% success rates, produces O(logN) messages per query and can locate target file within O(logN) hops.
查看更多>>摘要：Based on the microscopic elasticity theory and microscopic diffusion equation, the precipitation progress of the binary alloys including coherent strain energy was studied. The results show that coherent strain has obvious effect on the coherent two-phase morphology and precipitation mechanism. With the increase of coherent strain energy, the particles shape changes from the randomly distributed equiaxed particels to elliptical precipitate shapes, their arrangement orientation increases; in the late stage of precipitation, the particle arrangement presents obvious directionality along the [10] and [01] directions, and the precipitation mechanism of alloy changes from typical spinodal decomposition mechanism to the mixture process which possesses the characteristics of both non-classical nucleation growth and spinodal decomposition mechanisms.
查看更多>>摘要：The tire mark is the important legacy information left at the accident scene. Based on the vehicle collision dynamics model, this study provided an optimized algorithm with vehicle final location and other related information for the tire marks. When the tire marks simulation results fit the real one well, the state of vehicle can be understood as the real state in the accident. Based on above, the vehicle velocity and direction are decided. According to the velocity and direction of the vehicle, the complete accident process can be simulated. With the help of the Pc-Crash software, the method has been applied in typical collision accident cases analysis. The reconstruction results will provide the scientific and numerical references for vehicle collision accidents analyzing and appraising.
NETL
NSTL