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A non-suction controlled method of wetting-drying cycles for unsaturated compacted loess material has been studied in this paper. The specimen was wetted by a sprayer and dried by air and the moisture content was controlled by measuring the specimen mass. Calculated moisture content was investigated and compared with measurement data. It can be indicated from the results that the method is effective, accurate and time-saving for controlling moisture content of compacted loess.

Forecasting and evaluating the safety of mine main ventilator are helpful to prevent mine ventilation safety accidents from happening. First, on the basis of collecting and analyzing a large quantity of fault information of main ventilator in the nationwide coal mine, the index system was established for safety evaluation of coal mine ventilator. Second, the remark set was set up. Then, weights of safety estimation index of mine main ventilator was determined by using Analytic Hierarchy Process(AHP). With the experts grading method, single-factor matrix of fuzzy evaluation was established. Last, mathematical model of fuzzy comprehensive evaluation was settled for mine main ventilator based on fuzzy theory and used to evaluate the safety of the coal mine main ventilator. The current safety assessment level of coal mine ventilator is “basically safe” and the result can be used to make decisions.

In view of the LLC series resonant converter topology, it is well known as suitable for small and medium power application, the stabilization of output voltage and the environment of step-dowm. The scheme is proposed for a kind of the step-up DC/DC transformer based on LLC resonant full bridge. The detailed design method is given. The 3KW prototype is built. The experimental results show it has the characteristics of the constant current discharge, wide working frequency and high power desity, as well, the feasibility is verified.

Catalyst by different carriers prepared of carbon dioxide conversion sequence is: Ni/TiO2> Ni/γ-Al2O3> Ni/MgO > Ni/SiO2. Second metal, Co, Mn, Cu, La and Ce, was significantly enhanced the activity of methanation nickel-based catalysts in the carbon dioxide methanation reaction, but second metal of Cu was bad for the activity of methanation. The 10%Ni/Al2O3 and 2.5%Ce-10%Ni/Al2O3 catalysts were characterized by TG and H2-TPR，it was revealed to Ce which is benefit for reduce NiO reduction temperature and the optimal reduction temperature of the catalysts in between 400°C and 500 °C

Phosphogypsum is a by-product of industrial phosphoric acid producing with wet method, a simple and efficient way to produce high quality CaCO3by phosphogysum is presented in this work. Calcium in the phosphogypsum converts into Ca (OH)2with the addition of NaOH, acid insoluble substances and metal ion which was also separated from calcium in phosphogypsum by HCl and NH3·H2O respectively. The purity and whiteness of CaCO3produced by the carbonization of purified CaCl2solution are 98% and 96%. The optimum mass ratio of phosphogypsum, NaOH and HCl was 25:12:35. Chemical characterization of the resultant CaCO3was performed by XRD, SEM, TG and chemical titration method, which indicate that this method is effective in producing spherical CaCO3at room temperature, moreover, the purity, whiteness and thermostability of calcium carbonate can meet most of application requirements for industrial CaCO3.

The purpose of particles impact drilling is to increase the rate of penetration when drilling extra-hard and strong-abrasive rocks, where supposed to be time-consuming and costly. Now the technology becomes the world’s most potential drilling technology for deep wells and ultra-deep well. The most important part of the drilling technology is the nozzle which accelerate the particles. The paper introduces the basic four types of the nozzles, and researches the acceleration effect of nozzles based on FLUENT. By concluding the simulation, put up a new structure of nozzle, and simulates the acceleration of the particle of different drilling fluid and particles inlet velocities, discusses how the length of accelerating cavity affect the acceleration.

In this paper, a multi-band chiral metamaterials (CMMs) based on complementary cross-wire structure is proposed and studied numerically. The finite element method (FEM) method was used to simulate the EM properties of the designed structure. Numerical results indicate that the giant optical activity and multiband negative refractive index can be realized in terahertz region. The proposed CMMs may have some potential applications in novel terahertz device.Particle size of bayerite (d50) was about 24 μm. Al2O3was obtained after calcination at 1050 °C for 1.5 h.

The real-timely estimation of the SOC (state of charge) is the key technology in Li-ion battery management system. In this paper, to overcome the error of the SOC estimation of Extended Kalman filter (EKF), a new estimation method based on modified-strong tracking filter (MSTF) is applied to SOC estimation of Li-ion battery, based on the second-order RC equivalent circuit model. Experiments are made to compare the new filter with the EKF and Coulomb counting approach (Ah). The simulation results demonstrate that the new filter algorithm MSTF used in this paper has higher filtering accuracy under the same conditions.

The traditional quality testing method does not apply for the new electronic device which have characters that high-value and small-count, take advantage of the small sampling theory, we can reduce the number of test sample significantly by using the Bayes method. In the processing of the experimental data, we can improve the accuracy of the quality assessment of electronic devices by using of the Bayes method and make full use the prior information.

The logical choice of stator voltage vector is the key for induction motor direct torque control. This paper proposes a stator voltage vector selection rule based on wiring, according to analyzing the affection caused by the electrical wiring on motor stator voltage amplitude and phase. The rules are tested in direct torque control system. Experimental results show the correctness of the theoretical analysis.

The paper analyses the error factors of every part of the new pv fault diagnosis system which may affect the final diagnostic result and the fault positioning result. According to the different characteristics of each factor, we present the effective methods from the aspect of hardware or software to eliminate or reduce the errors, so the precision of the whole system can be improved.

RE nanophase composite material between the grain size 30nm and 100nm are prepared by the method of mechano-chemistry，in which the material’s adsorptive capacity to metal base is checked，and the nature of anti-friction as well as self-repairing effectiveness to the surface of abrasion is tested by four-ball friction wear testing machine. The results show that RE nanophase composite material prepared by the method of mechano-chemistry has a good adsorptive capacity to metal base，and the wear surface can be covered and repaired under dynamic condition；RE nanophase composite material used as anti-friction material is test and verified.

Incremental method, as one of the practical calculation methods in retaining structure design of foundation pit, has been widely used. When incremental method is applied, the earth pressure, acting on the retaining structure on each incremental step, is considered as static earth pressure. Actually, the state of earth pressure changes constantly with the increase of soil displacement in the process of excavation. This paper introduces the relation of displacement and earth pressure based on the soil stress-strain state, and makes corrections for the earth pressure of the incremental method. By comparing with the measured data of the engineering, the calculation results, which consider earth pressure modification, are in good line with the practical engineering condition. The method in this paper can provide certain reference for related engineering design.

Based on the newly introduced d-decisional Diffie-Hellman (d-DDH) intractable problem, a signature scheme and a multi-signature scheme are proposed. The main method in the constructions is a transformation of a knowledge proof on the equality of two discrete logarithms. The two schemes are proved secure in the random oracle model and the security reductions to the d-DDH problem are tight. Moreover, one can select different d for different security demand of applications. Thus the schemes are secure, efficient and practical.

An improved chaos particle swarm optimization (CPSO) algorithm is proposed on path planning for unmanned aerial vehicle (UAV) to overcome the inadequacy of particle swarm optimization (PSO) algorithm, which falls into local optimum easily and converges slowly in process with poor precision. Through the in-depth analysis of PSO algorithm, the chaos optimization (CO) algorithm principle is introduced into it based on the traditional update operations on the particles’ velocity and position; as a result, the diversity of particles is increased, the suboptimal search on path planning is avoided and the quickness accompanied with accuracy of convergence is improved. Combined with digital map for modeling the UAV’s flight environment, the 3-D path planning is achieved. As the simulation results demonstrated, this hybrid algorithm is superior to the traditional PSO algorithm on path searching, especially in the 3-D environment.

In electric vehicle management system, the key technology is to estimate the SOC (state of charge) of battery in dynamic process. This paper builds the state space equation of lithium battery based on improved Randle’s model, realizes the tracking estimation of SOC using modified STF(strong tracking filter) algorithm. The simulation result proves that compared with the original algorithm, modified algorithm can greatly improve the system’s tracking ability as well as the estimation accuracy of SOC.

In this paper, a method of detecting adult images based on AdaBoost was proposed. We focused on the detection of the adult images that have naked breasts or naked genitalia. By using basic and rotated Haar-like features extracted from the samples in the training set, we trained a cascade detector. The detector would classify the image whether to be a pornographic one or not. The results showed that this method achieved a high detection rate and a low false alarm rate.

This paper describes a nonlinear adaptive dynamic inversion controller for a flexible air-breathing hypersonic vehicle model. The complete characterization of the nonlinear internal dynamic of the Bolender and Doman model with respect to velocity，altitude and angle as the regulated outputs is considered in this paper. The derivation of the internal dynamics presented in this work is comprehensive of the flexible dynamics. For the purpose of control design，we decompose the equations of motion into functional subsystems，namely，the velocity subsystem，the altitude and flight-path angle subsystem，and the angle of attack and pitch rate subsystem. Each subsystem is controlled separately using available inputs and intermediate virtual control commands. The adaptive fuzzy system is then developed to identify the uncertain in the model parameters. Simulation results are provided to demonstrate the robustness and the efficacy of the proposed controller

In this paper, an Improved Nonsingular Terminal Sliding-mode (INTSM) observer is proposed to estimate the speed of the permanent magnet synchronous motor (PMSM). The Nonsingular Terminal Sliding-mode (NTSM) not only inherits the good performance to track the state error, but also has the characteristic of limited time convergence. However, the conventional NTSM control law is too complex to apply in practice. The INTSM takes the thoughts of the fast Terminal Sliding-mode and uses a new nonlinear term to replace the conventional term. As a result, the new observer owns the characteristics of global fast convergence and simple control law. At last, the proposed method proves to be effective through the theoretical analysis and simulation test.

Electricity transformer is an important, widely used electrical equipment. Current the iron beam sectional of the electricity transformer is based on experienced standards which can not achieve the best economic benefits. According to practical technology, we build a basic optimization model about multistep iron beam section. And we also give a reasonable design on the tolerance zone between the diameter of iron beam sectional circumcircle and the diameter of the winding steel-flue, as well as the arrangement about the oil path in the iron beam, which has a big realistic significance and application value. We come up with five reasonable model assumptions to simplified the problem, turning the tolerance zone design problem into the function extreme one. We adopt "Ideal assumption first, specific modification second" method on designing the oil path, considering all kinds of situations to obtain optimization. The core algorithm is dynamic programming which is much faster, much more stable than using Lingo. All the solving and analyzing on math models are based on C++ programming language.

An adaptive model reference parameter identification method without sensors for PMSM is presented in this paper and this method is based on double manifold sliding mode. The real model of PMSM is selected as the reference model and the d/q frame observer which is constructed using current model of the motor is selected as the adjustable model. The manifold sliding mode surface is constructed using the output (current in d/q frame) errors of the two models. Proper parameters are selected to guarantee the stability of the observer. The adjustable model converges to the reference model and the running state of motor can be identified. Theoretical analysis and simulation results show that the proposed strategy has high static and dynamic performance，high tracking precision as well as stronger robustness.

In Section 1, we describe process of ball-bat collision using kinetic model, and derive the post-collision ball speed as a function of the hitting location. Then we differentiate the function and find out where the sweet spot is. The result successfully explains the best location is not at the end of the bat in consistent with our practical experience. In Section 2, based on the model in Section 1, we add two assumptions, supposing corking only influences mass and moment of inertia of bat. Then the maximum outgoing ball speed is only depended on mass of bat. The result shows properly corking will enhance the bat performance. In Section 3, we explain “trampoline effect” in dynamic model and throw light on energy transformation in collision process. We conclude that COR is related to materials, and aluminum bats perform better than wood bats.