Abstract:In view of the universal present situation where general rural buildings have low earthquake resistance ability，a new type of practical, economical, simple and reliable seismic technology called steel-asphalt composite isolation pier was put forward. Specimens were made according to the correlation theory, and experiments on a masonry model were also carried out. The tests have shown that the steel of the isolation pier works in the elastic range when the peak value of the acceleration is below 0.3 g. The acceleration reduction factor of the isolation pier is between 0.14-0.67 when different peak values of the loading condition are input, and good damping effect can be obtained because most of the energy has been absorbed by the isolation pier especially to high frequency loading wave. The details of the seismic design of rural masonry structure can be reduced, and the funds thus saved can be used for this new steel-asphalt composite isolation pier. In the end, the total cost of the houses does not increase.

Abstract:An experimental study on the impact resistance of concrete filled steel tube (CFT) after exposure to high temperatures (100 ℃, 300 ℃, 500 ℃ and 700 ℃) under multiple impact loadings was carried out by using a Split Hopkinson pressure bar (SHPB). The strain and stress versus time relation curves of CFT specimens were measured to experimentally analyze the dynamic behaviors of CFT under multiple impact loadings. The test results have shown that CFT after exposure to high temperature experiences no remarkable strength deterioration and has excellent impact-resistance to multiple impact loadings. Concrete filled steel tube is excellently suitable to resist the possible progressive collapse of structures on fire and the double actions of high temperature exposure and blasting or impact loading caused by military attacks.

Abstract:An experimental study has been performed on Steel-Concrete Composite Castellated Beam (SCCCB). The basic mechanical performances of SCCCB, such as stress and deformation, were the focus of this study. The test results have indicated that, due to the influence of secondary bending, the peak stress is achieved in porthole. Based on vierendeel truss theory, the formulas considering the effect of ribbed stiffener to calculate the stress of SCCCB were proposed, the theoretical results are consistent with the test results, and the results indicate that the maximum stress of perforated web appears at the angle of 150~165°. Also, a formula for the evaluation of the deflection of SCCCB was derived according to vierendeel truss theory. It is found that this method can satisfy engineering requirements by comparing theoretical results with both experimental and FEM ones. The analytical method can be used for the serviceability limit state design of SCCCB.

Abstract:A simplified approach was proposed to calculate the settlement of super-long pile subjected to vertical load. Firstly, a three-line model of load transferring was developed to simulate the transferring law of super-long pile considering the work hardening or work softening characteristics of the soil around the pile, and the theory of τ-z curve was also used to describe the nonlinear characteristics of the contact interface between pile and soil. Then, considering the relative slide, the pile and the soil were discret to establish units respectively, so the stiffness matrix equation and the method of iteration were also deduced according to the equilibrium conditions of the pile-soil system. Therefore, the method for the evaluation of the settlement of super-long pile considering the relative slide between pile and soil was proposed. Finally, the theoretical calculation was compared with the field test, and a good agreement has been obtained, which means that the calculation method can provide a reference to engineering practice.

Abstract:In order to solve the problem that it is hard to process the HVOF tungsten carbide coatings, super high speed grinding experiments were carried out. The grinding forces and the surface roughness were measured, and the surface microstructure was observed under different grinding conditions. The results have shown that, with the substantial increase in wheel speeds, the grinding forces and surface roughness can be significantly reduced. Under the conditions of super high speed grinding, the plastic gives priority to the coating material removal way. In a word, under the conditions of super high speed grinding, the surface quality and the grinding efficiency and service life of the grinding wheel in coating workpiece grinding have been obviously improved.

Abstract:Replacement purchase and dynamic market influence product diffusion, which limits the application of basic product diffusion model. In this paper, the dynamic market variables were constructed to reflect the changes of the market, and the extended product diffusion model was verified with influence coefficients considering replacement purchase and dynamic market factors. The mini cross-type passenger vehicle, which is one segment of China's automobile market, was empirically studied. The factors, including fuel price, product price, policies of the government and repeated purchase, were analysed in the extended diffusion model to analyse the target product diffusion rule. The results have indicated that the fitting degree of extended model is increased by 13% over the basic model, and the mean absolute percent error is decreased from 23.93 to 5.5. Therefore, the proposed extended model with perfect fitness and forecasting accuracy shows better performance in explaining the actual diffusion rule.

Abstract:Obstacle recognition is one of the key techniques for deicing robot on high voltage transmission line. According to the structure of 220 kV transmission line and the feature of special environment, the images photographed on line by the robot camera can be processed. Images have been binary converted on the basis of threshold optimization after some preprocesses of de-noising, expansion and erosion. Then, image edges were detected by using wavelet modulus maximum algorithm, and the wavelet moments of edge images that have invariance were calculated. The SVM begins to classify images after being put into eigenvectors that have been optimized into the neural network of SVM, which realizes the image classification of obstacle. Simulation experiments have indicated that eigenvectors of wavelet moments are stable and reliable and SVM classifier has a high accuracy of object recognition. It is a feasible method that combines both virtues.

Abstract:On the basis of tiles theory model and the existing self-assembly model, an algorithm based on DNA self-assembly model was presented for maximum clique problem, and the corresponding DAE blocks designed in particular for initial molecular, rules of molecular and the detection of molecular were given. Then, an algorithm for solving maximum clique problem was presented with the biologic operation of fluorescence labeling and gel electrophoresis. The proposed algorithm needs Θ(n2+|E|) types of tiles, and the complexity of experiment operation was Θ(1). This algorithm can reduce the complexity of the experiment, and ensure the ease of experiment and the accuracy of results.

Abstract:The transfer of harmonic between the AC and the DC system was investigated on the basis of the Fourier analysis of the voltages at both converter sides. Unbalanced AC voltages at AC side were represented by their positive and negative sequence components. The above method was used in the inductive filtering based HVDC system to analyze the voltage on the DC side of an HVDC converter bridge under unbalanced conditions. A comparison of the inductive filtering based HVDC system with the traditional DC transmission system in the same AC system fault conditions has shown that the former is superior to the latter for DC side harmonic amplitude suppression. In the end, referring to the parameters of the inductive filtering based HVDC system in the lab, a dynamic simulation was executed. The results obtained by switching the 2, 11 and 13 harmonics LC filters on the valve side of inductive filtering transformer have shown that the contents of non-characteristic harmonic voltage in DC voltage are suppressed significantly and the harmonic instability is suppressed effectively in the inductive filtering based HVDC system.

Abstract:The symmetry of three-phase output voltages is very important in the evaluation of the performance of AC power supply. In order to obtain high quality output voltage waveforms of three-phase UPS (uninterruptible power supply) under unbalanced loads and nonlinear loads, this paper analyzed the mechanism of the asymmetry of output voltages of UPS, and proposed a multiplex control scheme combining repetitive control with PI control based on DSP under synchronous positive/negative reference frame coordination. Power switch transistors were applied to Space Vector Pulse Width Modulation (SVPWM) model. Negative sequence components of voltages have almost been eliminated, and zero sequence components and harmonics of voltages have been weakened effectively. The prototypes of 30-500 kVA UPS have been developed, and the experiment results have verified the validity of the proposed control scheme.

Abstract:The MVDR beamformer has better spatial resolution and better interference rejection capability than the standard beamformer, provided that the signal steering vector is accurately known. However, in practical applications, the performance of MVDR beamformer degrades severely because of violation of underlying assumptions on the environment, sensor array and sample covariance matrix errors. To overcome the mismatches, a robust MVDR beamforming algorithm based on the diagonal loading was proposed. By considering the bad effect of steering vector errors on MVDR algorithm performance, and obtaining the optimal weight vector under the condition of the largest deviation, this algorithm can sufficiently reduce the effect of the mismatches and provide an improved robustness in the communication environment. Also, the algorithm uses a recursion process to avoid inversing matrix, which reduces the computational complexity and facilitates project implementation. The simulation results show that the proposed robust algorithm has better performance than the traditional MVDR algorithm.

Abstract:In this study, we have synthesized a series of new norlignan compounds ——2a~2g—— and evaluated their anticancer activities with MTT assay by using human hepaioma Bel-7402 cells, human breast adenocarcinoma MCF-7 cells, human lung carcinoma A549 cells and human cervical carcinoma HeLa cells. It has been shown that the products (——2a~2g——) exhibit higher cytotoxicity to cells, and especially, product ——2b—— treated with Bel-7402 cells shows a lower cytotoxicity (IC50: 18.9 μg/mL) than free paclitaxel.

Abstract:This study addresses the morphological changes of Trichoderma reesei HC-415 in the process for cellulase production in 30 L fermenter. It was found that the morphological changes of HC-415 could be divided into four periods in the process of fermentation. The hypha morphology during the first period showed that filamentous elongation with less branching and the enzyme production was almost at a stationary phase after vaccinations within 0~24 h. Next, the mycelial length and the number of branches increased, the stem became thick and the enzyme activity significantly increased after vaccination within 24~60 h. Then, mycelium with septa became short and thick, and this was accompanied by the appearance of many enlargement round nodules at the top of the branches after vaccination within 60~132 h. This was the period of rapid growth and peak stability of cellulase activity. Finally, the number of thick and short round mycelium with many enlargement nodules declined, accompanied by the gradual decline of enzyme activity after vaccination for 132 h. The results demonstrated that a tight correlation existed between the morphological characteristics and the cellulase production and the activity of Trichoderma reesei in liquid. Furthermore, the morphological characteristics can be used as an important indicator for the regulation of fermentation broth of maturity in the production of cellulase.

Abstract:Ramie fiber was treated with amino silicone oil. The properties of ramie fiber were investigated with IR, contact angle test, XRD, and TG. The results have shown that some silicone molecules were coated on the surface of the modified ramie fiber, and it reduced the number of hydroxyl groups on the ramie surface. The crystallinity of ramie fiber was increased by 15%, and the water absorption of the modified ramie fiber was decreased, inducing a better compatibility between ramie fiber and polypropylene. In addition, the weight of the unmodified fiber had a loss of 5% before 230 ℃, while the modified ramie fiber had no decomposition virtually, so that the heat resistance of the modified ramie fiber has been greatly improved.

Abstract:The thermal stabilization of PI / Al2O3 hybrid films was studied with TG. Meanwhile, the kinetics parameters (activation energy of thermal decomposition, collision coefficient and action progression) were calculated, and the upper limit temperature was predicted according to the relevant data. The experiment results showed that the order of reaction in air atmosphere was bigger than that in nitrogen atmosphere, and tended to second-order reaction. The value of E calculated by the method of Kissinger was lower than that in the method of Coats-Red fern. The collide coefficient (A) was calculated in the method of Coats-Red fern selected by contrast, and the upper limit temperatures of hybrid PI material was nearly 300 ℃ similar to those reported in previous literatures. The results have shown that Coats-Red fern method is one of the reliable methods to predict the long-term life upper limit temperature of hybrid PI materials.

Abstract:GIS sampling location technology and the atomic absorption spectrometry technology were applied to study the impact of the exposed environmental risks of river water, bottom sludge, waterfront animals and plants and inhabitants' health. The results show that, in the past 30 years, the total contribution of chromium (VI) pollution migrating along the Chang-Zhu-Tan section of the Xiangjiang River has been 13.21%, the amount of chromium (VI) in the river water has been 3~6 times compared with the background standard, and the species of plants in the river and waterfront has been sharply reduced by 23%. And the blood and muscle chemical checking of the animals show that the amount of chromium (VI) has been 1.5~4.5 times over the national standard, the inhabitants' average longevity in the villages along the polluted river section has been reduced by about 2 years, and the normal disease and cancer suffering rate has been increased by 25% and 3.05%, respectively. Moreover, some proposals were presented for the above environmental risks.

Abstract:The effects of water flow under different light intensity on the growth of Microcystis aeruginosa were studied to elucidate the mechanism of water bloom. The experiment was conducted at a light intensity of 2 500 lx and 3 500 lx in a small perspex ring groove，which generated water flow under axenic condition and constant temperature and light. The results showed that the adaptation growth time of Microcystis aeruginosa increased, the exponent growth time was extended and the growth ratio was improved by water flow, which directly influenced the density of algae, and that the effects of water flow on the growth of Microcystis aeruginosa were related to light intensity. The light intensity at 2 500 lx was more conducive to the growth of Microcystis aeruginosa than that at 3 500 lx, the optimal water flow was 35 cm/s both for the light intensity of 2 500 lx and 3 500 lx. There were no significant differences among different water flow at the intensity of 2 500 lx. Therefore, there are not significant differences at 3 500 lx. The light intensity requirement was decreased and the efficiency was increased by water flow.