In order to study on chaotic characteristic of mine blasting seismic wave propagation,and based on phase-space reconstruction with different distance from blasting seismic wave, this paper calculated the time delay and correlation dimension of blasting seismic wave in different distance. The results show that with the increasing of propagation distance, blasting seismic wave correlative dimension of time series decreases linearly and tends to be stable and saturated,and the bigger the correlation dimension, the more obvious the chaos characteristics. Chaotic is the substantive characteristics of blasting seismic wave in time series. The research results will beneficial for further understanding the nonlinear characteristics of seismic wave.
To accurately forecast the climate conditions of the heading face with high temperature and take proper cooling measures, the calculation of the temperature field of surrounding rock is necessary. According to the moving boundary, the mathematical model of the temperature field of surrounding rock was established in moving coordinate. The model was nondimensionalized by introducing dimensionless parameters. The dimensionless model was dispersed with finite volume method, and then a computation program was developed. Taking the heading face which dimensionless length is 25 for example, the dimensionless temperature distribution of the surrounding rock is obtained by assuming both the Biot coefficient and Peclet coefficient to be unity. The unstable heat transfer criterion distribution of the surrounding rock under different conditions is obtained as well. The variation curves of the unstable heat transfer criterion with increasing Peclet coefficient are obtained with different values of the Biot coefficient, which reveal that the unstable heat transfer criterion increases with the increase of Biot coefficient and Peclet coefficient. The unstable heat transfer criterion can be determined by consulting graphs, and this method provides critical parameters for air temperature forecasting and chilling requirement calculation in heading face.
In order to study the displacement directions of the both sides of fault tectonic after strong rock bursts, the paper established tectonophysical model of rock burst, and analyzed the dependent phenomenon of fault displacement from the view of the tectonic stress field, which does not belong to the mining technogenic. Through the study of Ural mining area and Beipiao mining area, this paper found out the correlationship between displacement vectors along faults and mining technology during tectonic rock bursts caused by mining. The displacement along major faults is consistent with the existence of tectonic stress field. The analysis of the relationship between the displacement of fault plane and the direction of tectonic stress field, as well as, the ratio between inoculating rock bursts R and source size, shows that the fault tectonic rock burst with wing sliding is the result of regional modern tectonic movement, and mining engineering activity is just the cause.
Based on drill hole data, 2D coal seam boundary line and fault lines, techniques for automatic modeling of 3D coal seam with faults and no-coal area were studied. Point set containing intersection points of drill and seam roof or floor and interpolated points of no-coal drill was utilized to generate a Voronoi diagram,which was used to determine the no-coal area boundary line according to the affected region of no-coal drill. Elevation values of points belonged to coal seam boundary line, fault lines, no-coal area boundary lines and grid points of coal seam roof and floor were interpolated. Inverse distance weighting method used for elevation values interpolating was improved from two aspects. One was optimizing the neighbor sample points by quadrant search and amount constrained of drill,the other was excluding the sample points on the different side of the fault by calculating the number of intersection points between fault line and the line connecting interpolated point to sample point. Then, coal seam roof and floor surface model were built by constrained Delaunay triangulation of interpolated lines and grid points. The overlapping region of reverse fault was deal with individually, interpolating the elevation values twice of fault lines and grid points as hanging wall and foot wall separately and modeling the surface. Finally, the 3D model of coal seam was constructed by combining the surface model built previously.
For calculation method about wind vibration coefficient of cup type transmission tower widely used, this paper presented different calculation methods, and simulated the fluctuating wind based on random vibration theory using Davenport spectrum. Wind vibration coefficient of simulation results were obtained through analyzing the finite element models. The results was compared with standardize operation results in order to find the change rule of cup type towers wind vibration coefficient. The results show that the wind vibration coefficient of tower body calculated according to the specification is close to the simulation results. But standard formula appears obviously deficiencies on crank arm and cross arm, so the stiffness mutations should be taken into account to calculate the wind vibration coefficient of crank arm and cross arm.
To predict coal spontaneous combustion in caving zone, 8 relevant factors were selected from three aspects of temperature and indicator gases and drilling parameters. Logistic regression analysis wai\s used to extract 5 important parameters to be input. To improve generalization ability and prediction accuracy of extreme learning machine, particle swarm optimization algorithm was applied to optimize the input connection weights and hidden layer threshold of ELM,and PSO-ELM forecasting model was built. Experiment was performed on 28 groups of training data and 12 groups of testing data. The result shows that PSO-ELM forecasting model based on logistic regression analysis has high prediction accuracy, and it is an effective method for completing the prediction of coal spontaneous combustion.
To know status of the transformation of scientific and technological achievements in universities, research institutes and enterprises in Anhui Province, by means of interviews, telephone calls and face to face talks, the main problems in transformation of scientific and technological achievements in Anhui Province are analyzed. Countermeasures are put forward to promote transformation of scientific and technological achievements, accelerate innovation of science and technology in Anhui Province and narrow the gap of innovation of science and technology with Yangze River Delta.
In order to research the global exponential stabilization problem memristive neural networks with time delays, and overcome the difficulties caused by the abruptly jumping of memristive synaptic connection weight matrices, non-smooth analysis and differential inclusions are employed to present the definition of a solution in Filippov sense. By utilizing Lyapunov stability theory, delay-dependent feedback control laws are derived to achieve the exponential stabilization for the concerned network model. The proposed feedback control law can be applied to most of the existing memristive neural network models. The proposed stabilization methods are simple and can be easily realized. The obtained results characterize fundamental electrical properties of memristor devices and provide convenience for its applications.
In order to research friction loss of cured bridge, experimental and theoretical analysis methods were used based on the formula for prestress friction loss in the specifications. Actual simulation of engineering was analyzed by using highway bridge structural analysis software DR. Bridge, and the simulation was based on the experiments of restressed friction and the deformation anchor prestress losses of practical Engineering. The results show that some deviations are existing of K values between specifications and calculated value by testing data, and construction factor has great influence on the bias factor of pipleline. Actual value is close to the simulation value by reckoned through testing data μ value and k value, which further illustrates the reliability of the actual value. Pipe friction and bias conditions are well reflected by the value μ and K. The results of analysis provide a positive role for the curved bridge design, monitoring, construction, maintenance and so on.
In order to reveal the development of commercial banks, this paper uses the DEA model to estimate the technical efficiency, pure technical efficiency and scale efficiency of Chinese commercial banks in 2008-2012. The results show that the overall efficiency of Chinese commercial banks shows a steady upward trend, and the improvement of technical efficiency is mainly derived from scale efficiency; In addition, five state-owned commercial banks, technical efficiency, pure technical efficiency and scale efficiency are lower than the level of joint-stock commercial banks; the trend of the efficiency of state-owned commercial banks and joint-stock commercial banks remains the same with the trend of the overall efficiency of Chinese commercial banks.
In view of the problem that the robustness of feature is poor and the complex function fitting ability is weak in classification, a pedestrian detection method based on texture feature and deep learning is proposed. Firstly, Put forward an improve GSRLBP texture feature extraction algorithm for extract the local texture feature of pedestrian images, through obtain gradient information of the pixel and combine the GSRLBP elimination of ill effects about small perturbation; in addition, set up deep learning pedestrians sample classifier based on deep belief network, make use of the input and middle layer RBM structure, which achieve data transfer between the hidden layer structure, realize the self-learning of the feature data. And, the BP neural network is used for output of classifier, which can optimize the classification structure. Experimental results show that the propose method is workable and effective, which performs better than the classic shallow machine learning pedestrian detection algorithms.
The bearing mechanism and failure pattern of reinforced slope pile anchor with rotary jet mixing were discussed. And a mechanical model was established to calculate the bearing capacity of this new type of anchor. Based on the Mohr-Coulomb earth pressure theory, a calculation formula of ultimate bearing capacity was derived out for the slope pile anchor with rotary jet mixing. Finally, the rationality of the calculation theory and formula was verified by the practical engineering examples. The researching results indicates that the reinforced slope pile anchor with rotary jet mixing can effectively improve the bearing capacity of pre-stressed anchor cable in the soft soil stratum. This study has very important significance for optimizing the design parameters of pile anchor retaining structure and improving the overall efficiency of retaining structure.
There are many faults often occurring currently in the mine hoist brake,and the coupling signal may cause a relatively complex troubleshooting. The method of GA-BP neural network has been developed to diagnose the fault of mine hoist brake. The fault types and many dates of the mine hoist brake were collected by investigating and researching related literature,then the input and output vector of network was confirmed based on the GA-BP neural network. GA-BP neural network fault diagnosis was simulated by writing in Matlab programs. The results show that the diagnosis error is small and the output is consistent with fault of diagnosis,so it is effective and feasible in applying GA-BP neural network in fault diagnosis of mine hoist brake.
为研究深基坑支护结构变形特性,以新景世纪城基坑工程为例,采用数值模拟手段对该工程变形特性进行了仿真分析,运用现场监测数据验证了数值模型计算的准确性,深入分析了深基坑支护结构变形的影响因素.结果表明:抗剪强度指标越大,基坑位移越小,但不是特别明显;增加灌注桩的桩径、嵌固深度和锚杆长度,可以有效的抑制基坑位移,但是增加到一定程度时,这种抑制基坑变形的效果不但十分有限,还会大大增加成本消耗;锚杆倾角在15°左右时,支护结构变形较小.
In order to analyze the assembly of the shear performance of three reinforced concrete shear capacity, this paper conducted charpy test to study the different beam interface assembly location of shear carrying capacity, oblique crack development patterns, shear pressure destruction process impact of changes in member displacement curve, longitudinal reinforcement and stirrups strain development law, shear properties of the ultimate bearing capacity and connectivity of old concrete interface, and with the whole cast beam test performance were compared. The results show that in the loading process, the assembly beam interface areas, cracks extend rapidly with weakening in section stiffness, but shear strength properties and deformation capacity and overall cast beams similar cracking load and ultimate load with the whole pouring contrast beam are basically the same.
According to the existing problems for fatigue life estimation method of enclosed storage bunker, this paper took a circular storage bunker of a power plant in Zhangzhou Houshi as the engineering case study, based on the Miner accumulated damage theory, analyzed the fatigue damage problem of double-layer reticulated shell structure caused by the vibration of the coal-transportation trestle, and calculated the fatigue life of components by means of the numerical analysis of finite element analysis software(ANSYS Fe-safe). Research results show that the fatigue failure of structure occurs after more than 4 million times of cyclic loading, and the damage region mainly appears the welds of joints. This study provides the theoretical basis for the fatigue safety design of circular storage bunker double shell structure and laid the foundation for the development prospect of the suspension structure.
为仿真描述有源风网上外源气体涌入运移过程,创新引入事件步长法,把风网中外源气体组分运动到达某一节点作为一个事件,同时取同期其他分支事件所经历的最短时间作为下一个时间步长,考察记录网络分支中外源气体到达的位置.为减小截断误差,对过大的事件时间步长作出限定,形成所谓“时间-事件混合步长”法.使每个迭代时间步长都能至少有外源气体到达某一个节点,采用节点分支汇流法计算节点浓度,使网络节点上气体浓度得到及时更新.结合矿井瓦斯突出流在网络中的扩散给出了算例,展示了不同时刻瓦斯达到网络各个节点的过程.研究结果表明:新方法能够自动截取网络中组分气体流动的微小事件变化,防止因过大的时间步长导致的截断误差;与单纯的时间步长法相比,计算精度高,模拟仿真更准确.
