In order to synthesize ZnO nanoparticles economically, industrial-grade zinc sulfate and urea were utilized to synthesize ZnO precursors in a stirred-tank reactor or a Teflon-lined autoclave at 100–180 °C under complete sealing condition. The ZnO precursors were calcined at 450 °C for 3 h to synthesize ZnO nanoparticles. The composition of the precursors and the formation mechanism of ZnO were studied by thermogravimetric analysis and Fourier transform infrared spectroscopy. The results of X-ray diffraction, transmission electron microscopy and scanning electron microscopy of the ZnO powders demonstrate that high-purity zincite ZnO nanoparticles are synthesized. Orthogonal experiments were performed to find out the optimal conditions for the maximum yield and the minimum size. The effect of temperature on the size of ZnO nanoparticles was investigated. The results show that a higher temperature is propitious to obtain smaller nanoparticles.

Effect of element cerium (Ce) on microstructure and mechanical properties of Al-Zn-Mg-Cu alloys has been investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and hardness test. The results show that addition of Ce can remarkably refine the as-cast grains and eutectic microstructure. A transformation from Mg(Zn,Cu,Al)₂ phase to Al₂CuMg phase is observed during homogenization. Furthermore, the Ce addition introduces changes in the precipitation process and consequently in the age-hardening behavior of the alloy. Microstructural measurements reveal that the addition of Ce promotes the precipitation of η′ phase, but it also partly retards the precipitation of GP zones. The density of precipitates decreases in a certain degree and rod-like η′ precipitates increase when Ce content is from 0.2% to 0.4% (mass fraction).

Numerical simulation combined with experimental test was carried out to analyze the pre-stretching process of the 7075 aluminum alloy sheet, from which the stress variation curves and residual stress of aluminum alloy sheet in different stretch rates were obtained. The results show that the residual stress in length direction is released after unloading the stretch force, while the residual stress in width direction is released during the stretching process. The study of residual stress elimination is beneficial for optimizing stretch rate on the basis of residual stress distribution law. By comparing the variation principle of residual stress in length direction, the size range of three deformation areas and elimination percentage of residual stress were obtained. The residual stresses of clamping area and transition area are not eliminated effectively, so sawing quantity should be the sum of both the areas. The elimination rate of residual stress in even deformation area could reach 90% after choosing a proper stretch rate, which is verified by both simulation and experiment.

Casting-cold extrusion technology was presented to fabricate aluminum/copper clad composite, and copper tubes with different sketch sections were designed. The technology of aluminum/copper clad composite fabricated by casting-cold extrusion was simulated by DEFORM software using tubes with four arc grooves. The stress and strain in different deformation zones were analyzed. The groove size reduces gradually and the groove shape drives to triangle during the extrusion procedure. The maximum values of equivalent effective stress and radial stress appear in groove zones, and the maximum equivalent effective strain firstly is obtained also in groove zones. The grain size in groove zones is less than that in other zones. The experimental results are consistent with simulation results, which prove that the copper tubes with sketch section are favorable to the metallurgy bond of boundary interface between aluminum and copper.

Two hafnium diboride based ceramic matrix composites containing 20% (volume fraction) SiC particle and with or without AlN as sintering additives were fabricated by hot-pressed sintering. The mechanical properties and microstructures of these two composites were tested and the thermal shock resistances were evaluated by plasma arc heater. The results indicate that the composite with AlN as sintering additive has a denser and finer microstructure than composite without sintering additive, and the mechanical properties, thermal shock resistance of the composite with AlN as sintering additive are also higher than those of the composite without AlN. Microstructure analysis on the cross-section of two composites after thermal shock tests indicates that a compact oxidation scale contains HfO₂ and Al₂O₃ liquid phase is found on the surface of composite with AlN, which could fill the voids and cracks of surface and improve the thermal shock resistance of composite.

A simulation calculation model for the solubility of insoluble compound M_mA_a in complex system was established. According to coordination equilibrium principle, relevant dissociation reaction, complexation reaction, self-complexation reaction and protonation reaction during insoluble compound dissolving were considered and then the mass balance equations about solubility calculation were obtained. In the case analysis, the solubility of silver chloride in ammonia system was obtained by simulation calculation, and curved surface charts of thermodynamic equilibrium about the total concentration of silver ions, pH and concentration of ammonia ions were drawn correspondingly. The results show that under the conditions of room temperature and 6 mol/L ammonia concentration, the calculated solubility value of silver chloride (34 g/L) is close to the actual value (31 g/L), demonstrating that this model is suitable for solubility calculation of insoluble compound M_mA_a in the complex system.

Determination of dissolution rate of alumina is one of the classical problems in aluminum electrolysis. A novel method which can measure the dissolution rate of alumina was presented. Effect of factors on dissolution rate of alumina was studied intuitively and roundly using transparent quartz electrobath and image analysis techniques. Images about dissolution process of alumina were taken at an interval of fixed time from transparent quartz electrobath of double rooms. Gabor wavelet transforms were used for extracting and describing the texture features of each image. After subsampling several times, the dissolution rate of alumina was computed using these texture features in local neighborhood of samples. Regression equation of the dissolution rate of alumina was obtained using these dissolution rates. Experiments show that the regression equation of the dissolution rate of alumina is y=−0.000 5x³+0.024 0x²−0.287 3x+ 1.276 7 for Na₃AlF₆-AlF₃-Al₂O₃-CaF₂-LiF-MgF₂ system at 920 °C.

The dissolution kinetics of malachite was investigated in ammonia/ammonium sulphate solution. The effects of ammonia and ammonium sulphate concentration, pH, leaching time, reaction temperature, and particle size were determined. The results show that the optimum leaching conditions for malachite ore with a copper extraction more than 96.8% are ammonia/ammonium concentration 3.0 mol/L NH₄OH + 1.5 mol/L (NH₄)₂SO₄, liquid-to-solid ratio 25:1 mL/g, leaching time 120 min, stirring speed 500 r/min, reaction temperature 25 °C and particle size finer than 0.045 mm. The dissolution process of malachite with an activation energy of 26.75 kJ/mol is controlled by the interface transfer and diffusion across the product layer. A semi-empirical rate equation is obtained to describe the leaching process and the reaction orders with respect to concentration of ammonia and ammonium sulphate are 2.983 0 and 0.941 1, respectively.

Two kinds of UV curable polyurethane acrylate oligomers (PUPA and PUCA) were synthesized via the addition reaction between isophorone diisocyanate (IPDI) and polyethylene glycol monoacrylate (PEA₆) or polycaprolactone modified hydroxyethyl acrylate (PCLA₂). The structures of PUPA and PUCA were characterized by Fourier transform infrared spectroscopy (FT-IR), ¹H nuclear magnetic resonance (¹H NMR), gel permeation chromatography (GPC) and differential scanning calorimeter (DSC), and the thermal stability and dynamic mechanical thermal properties of their cured films were measured by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA), respectively. The viscosity of the oligomers and mechanical properties of the cured films were also studied. The results show that both oligomers have narrow molecular weight distribution. The viscosity of PUPA is 2.310 Pa·s at 25 °C, while that of PUCA is up to 3.980 Pa·s. The UV cured PUPA and PUCA films have homogeneous phase structure, and the PUCA film shows higher glass transition temperature and storage modulus. Furthermore, the PUCA film possesses better mechanical properties than PUPA, while the latter shows better alkali resistance.

A series of Ag, Cu and Co-doped manganese oxide octahedral molecular sieves (OMS-2) were synthesized and evaluated to remove nitrogen oxides (NO_x) from cigarette mainstream smoke. The three kinds of catalysts were added to cigarettes for studying the capabilities of reducing NO_x from cigarette mainstream smoke. The catalysis and reduction of NO in laboratory were studied. A mechanism for NO_x catalytic reduction from burning cigarettes with the catalysts adding to cigarettes was described. The catalysts show excellent catalytic activity for NO_x removal, especially the Ag-doped OMS-2 catalyst. 0.5% (mass fraction) Ag-doped OMS-2 catalyst has the best ability to remove NO_x from cigarette mainstream smoke. The use of Ag-doped OMS-2 as catalyst for removing carcinogenic compounds from cigarette smoke will be an effective strategy to protect the environment and public health.

A newly developed heuristic global optimization algorithm, called gravitational search algorithm (GSA), was introduced and applied for simultaneously coordinated designing of power system stabilizer (PSS) and thyristor controlled series capacitor (TCSC) as a damping controller in the multi-machine power system. The coordinated design problem of PSS and TCSC controllers over a wide range of loading conditions is formulated as a multi-objective optimization problem which is the aggregation of two objectives related to damping ratio and damping factor. By minimizing the objective function with oscillation, the characteristics between areas are contained and hence the interactions among the PSS and TCSC controller under transient conditions are modified. For evaluation of effectiveness and robustness of proposed controllers, the performance was tested on a weakly connected power system subjected to different disturbances, loading conditions and system parameter variations. The eigenvalues analysis and nonlinear simulation results demonstrate the high performance of proposed controllers which is able to provide efficient damping of low frequency oscillations.

Due to the intense vibration during launching and rigorous orbital temperature environment, the kinematic parameters of space robot may be largely deviated from their nominal parameters. The disparity will cause the real pose (including position and orientation) of the end effector not to match the desired one, and further hinder the space robot from performing the scheduled mission. To improve pose accuracy of space robot, a new self-calibration method using the distance measurement provided by a laser-ranger fixed on the end-effector is proposed. A distance-measurement model of the space robot is built according to the distance from the starting point of the laser beam to the intersection point at the declining plane. Based on the model, the cost function about the pose error is derived. The kinematic calibration is transferred to a non-linear system optimization problem, which is solved by the improved differential evolution (DE) algorithm. A six-degree of freedom (6-DOF) robot is used as a practical simulation example, and the simulation results show: 1) A significant improvement of pose accuracy of space robot can be obtained by distance measurement only; 2) Search efficiency is increased by improved DE; 3) More calibration configurations may make calibration results better.

The flexible transmission shaft and wheel propeller are combined as the kinetic source equipment, which realizes the multi-motion modes of the autonomous underwater vehicle (AUV) such as vectored thruster and wheeled movement. In order to study the interactional principle between the hull and the wheel propellers while the AUV navigating in water, the computational fluid dynamics (CFD) method is used to simulate numerically the unsteady viscous flow around AUV with propellers by using the Reynolds-averaged Navier-Stokes (RANS) equations, shear-stress transport (SST) k-w model and pressure with splitting of operators (PISO) algorithm based on sliding mesh. The hydrodynamic parameters of AUV with propellers such as resistance, pressure and velocity are got, which reflect well the real ambient flow field of AUV with propellers. Then, the semi-implicit method for pressure-linked equations (SIMPLE) algorithm is used to compute the steady viscous flow field of AUV hull and propellers, respectively. The computational results agree well with the experimental data, which shows that the numerical method has good accuracy in the prediction of hydrodynamic performance. The interaction between AUV hull and wheel propellers is predicted qualitatively and quantitatively by comparing the hydrodynamic parameters such as resistance, pressure and velocity with those from integral computation and partial computation of the viscous flow around AUV with propellers, which provides an effective reference to the study on noise and vibration of AUV hull and propellers in real environment. It also provides technical support for the design of new AUVs.

Multistage centrifugal impellers with four different skew angles were investigated by using computational fluid dynamics. The purpose of this work is to investigate the influences of lean angle at the blade tip of the impeller inlet. Four variations of lean angles, that is, 8°, 10°, 15° and 20°, were made at first stage impeller. Reynolds Average Navier Stokes equation was used in simulation together with a shear-stress transport (SST) k-w turbulence model and mixing-plane approach, respectively. Three dimensional fluid flows were simplified using periodic model to reduce the computational cost and time required. A good performance was expected that the secondary flow can be effectively reduced in the flow passage of the impeller without excessive increase in manufacturing cost caused by the secondary flow. The results show that secondary flow affects the main flow intricately to form vortices or having non-uniform velocity in the flow passage, which in turn results in substantial fluid energy loss not only in the impeller but also in the guide vane downstream of impeller. The numerical solutions were performed and allowed the optimum design and operating conditions to be obtained.

In order to achieve the improvement of the driving comfort and energy efficiency, an new e-CVT flexible full hybrid electric system (E2FHS) is proposed, which uses an integrated main drive motor and generator to take the place of the original automatic or manual transmission to realize the functions of continuously variable transmission (e-CVT). The design and prototype realization of the E2FHS system for a plug-in hybrid vehicle (PHEV) is performed. In order to analyze and optimize the parameters and the power flux between different parts of the E2FHS, simulation software is developed. Especially, in order to optimize the performance of the energy economy improvement of the E2FHS, the effect of the different energy management controllers is investigated, and an adaptive online-optimal energy management controller for the E2FHS is built and validated by the prototype PHEV.

A novel active steering system with force and displacement coupled control (the novel AFS system) was introduced, which has functions of both the active steering and electric power steering. Based on the model of the novel AFS system and the vehicle three-degree of freedom system, the concept and quantitative formulas of the novel AFS system steering performance were proposed. The steering road feel and steering portability were set as the optimizing targets with the steering stability and steering portability as the constraint conditions. According to the features of constrained optimization of multi-variable function, a multi-variable genetic algorithm for the system parameter optimization was designed. The simulation results show that based on parametric optimization of the multi-objective genetic algorithm, the novel AFS system can improve the steering road feel, steering portability and steering stability, thus the optimization method can provide a theoretical basis for the design and optimization of the novel AFS system.

In operation, risk arising from power transformer faults is of much uncertainty and complicacy. To timely and objectively control the risks, a transformer risk assessment method based on fuzzy analytic hierarchy process (FAHP) and artificial neural network (ANN) from the perspective of accuracy and quickness is proposed. An analytic hierarchy process model for the transformer risk assessment is built by analysis of the risk factors affecting the transformer risk level and the weight relation of each risk factor in transformer risk calculation is analyzed by application of fuzzy consistency judgment matrix; with utilization of adaptive ability and nonlinear mapping ability of the ANN, the risk factors with large weights are used as input of neutral network, and thus intelligent quantitative assessment of transformer risk is realized. The simulation result shows that the proposed method increases the speed and accuracy of the risk assessment and can provide feasible decision basis for the transformer risk management and maintenance decisions.

Mobile WiMAX (worldwide interoperability for microwave access) air interface adopts orthogonal frequency division multiple access (OFDMA) as multiple access technique for its uplink (UL) and downlink (DL) to improve the multipath performance. All OFDMA based networks, like mobile WiMAX, experience the problem of high peak-to-average power ratio (PAPR). The high PAPR increases the complexity of analog-to-digital (A/D) and digital-to-analog (D/A) convertors, and also reduces the efficiency of RF high-power-amplifier (HPA). In this work, a new zadoff-chu matrix transform (ZCMT) precoding based random interleaved orthogonal frequency division multiple access (OFDMA) system was proposed for PAPR reduction in mobile WiMAX system. The system is based on precoding the constellation symbols with the ZCMT precoder before subcarrier mapping. The PAPR of proposed system is analyzed with the root-raised-cosine (RRC) pulse shaping to keep out of band radiation low and meet the transmission spectrum mask requirement. Simulation results show that the proposed system has better PAPR gain than the hadamard transform (WHT) precoded random interleaved OFDMA systems and the conventional random interleaved OFDMA systems. Symbol-errorrate (SER) performance of the system is also better than the conventional random interleaved OFDMA systems and the random interleaved OFDMA systems with WHT. The good improvement in PAPR significantly reduces the cost and the complexity of the transmitter.

A high-precision shape detecting system of cold rolling strip is developed to meet industrial application, which mainly consists of the shape detecting roller, the collecting ring, the digital signal processing (DSP) shape signal processing board and the shape control model. Based on the shape detecting principle, the shape detecting roller is designed with a new integral structure for improving the precision of shape detecting and avoiding scratching strip surface. Based on the DSP technology, the DSP shape signal processing circuit board is designed and embedded in the shape detecting system for the reliability and stability of shape signal processing. The shape detecting system was successfully used in Angang 1 250 mm HC 6-high reversible cold rolling mill. The precision of shape detecting is 0.2 I and the shape deviation is controlled within 6 I after the close loop shape control is input.

In order to accurately estimate the anti-penetration capacity of yaw-inducing bursting layer with irregular barriers on surface impacted by projectile, the theoretical model of attack angle and angular velocity for projectile impacting on irregular barrier was achieved according to the macroscopic relation of contact force versus contact time, in which the main factors such as the relative geometrical characteristics of projectile and irregular barrier, material property and impact velocity of projectile influencing on yaw-inducing effectiveness were considered. On the basis of considering synthetically the influences of attack angle, impact velocity, impact angle of projectile and uncontrolled free surface of target, the theoretical formulation of penetration depth for bursting layer with irregular barriers on surface impacted by projectile was presented by expressing the stress of an optional point on the nose of projectile according to the relation of stress versus velocity. The theoretical results indicate that in the case of oblique impact embodying effect of attack angle, the penetration depth is reduced with the increase of impact angle, attack angle or angular velocity, and penetration trajectory is also deflected obviously. The effectiveness of angular velocity influencing on penetration depth is increased with impact velocity increasing. The theoretical results are in good agreement with test data for low impact velocity.

New sigma point filtering algorithms, including the unscented Kalman filter (UKF) and the divided difference filter (DDF), are designed to solve the nonlinear filtering problem under the condition of correlated noises. Based on the minimum mean square error estimation theory, the nonlinear optimal predictive and correction recursive formulas under the hypothesis that the input noise is correlated with the measurement noise are derived and can be described in a unified framework. Then, UKF and DDF with correlated noises are proposed on the basis of approximation of the posterior mean and covariance in the unified framework by using unscented transformation and second order Stirling’s interpolation. The proposed UKF and DDF with correlated noises break through the limitation that input noise and measurement noise must be assumed to be uncorrelated in standard UKF and DDF. Two simulation examples show the effectiveness and feasibility of new algorithms for dealing with nonlinear filtering issue with correlated noises.

A self-adaptive learning based immune algorithm (SALIA) is proposed to tackle diverse optimization problems, such as complex multi-modal and ill-conditioned problems with the high robustness. The SALIA algorithm adopted a mutation strategy pool which consists of four effective mutation strategies to generate new antibodies. A self-adaptive learning framework is implemented to select the mutation strategies by learning from their previous performances in generating promising solutions. Twenty-six state-of-the-art optimization problems with different characteristics, such as uni-modality, multi-modality, rotation, ill-condition, mis-scale and noise, are used to verify the validity of SALIA. Experimental results show that the novel algorithm SALIA achieves a higher universality and robustness than clonal selection algorithms (CLONALG), and the mean error index of each test function in SALIA decreases by a factor of at least 1.0×10⁷ in average.

Similarity measure construction has been proposed as fault detection of flight test method in order to obtain the primary control surface stuck and the combination stuck of primary control. Similarity measures were obtained through analyzing the certainty and uncertainty of fuzzy membership functions, which were designed based on well-known Hamming distance. It was applied to the fault detection of primary control surface stuck of uninhabited aerial vehicle (UAV). At post-failure control surface, if the UAV is controllable and trimmable using other control surfaces, the UAV is able to fly or return to the safety region through reconfiguration of flight control system. To detect the fault, similarity measure computations were carried out. This result could be applicable with the real-time parameter estimation method. By monitoring the value of coefficients due to the control surface deviation, it becomes aware that the control surface fault occurs or not. The control surface stuck position and value were separated by comparing the trim value with the reference value. This is the advantage of increasing in reliability without adding sensors or with additional low cost.

To improve the segmentation quality and efficiency of color image, a novel approach which combines the advantages of the mean shift (MS) segmentation and improved ant clustering method is proposed. The regions which can preserve the discontinuity characteristics of an image are segmented by MS algorithm, and then they are represented by a graph in which every region is represented by a node. In order to solve the graph partition problem, an improved ant clustering algorithm, called similarity carrying ant model (SCAM-ant), is proposed, in which a new similarity calculation method is given. Using SCAM-ant, the maximum number of items that each ant can carry will increase, the clustering time will be effectively reduced, and globally optimized clustering can also be realized. Because the graph is not based on the pixels of original image but on the segmentation result of MS algorithm, the computational complexity is greatly reduced. Experiments show that the proposed method can realize color image segmentation efficiently, and compared with the conventional methods based on the image pixels, it improves the image segmentation quality and the anti-interference ability.

Role mining and setup affect the usage of role-based access control (RBAC). Traditionally, user’s role and permission assigning are manipulated by security administrator of system. However, the cost is expensive and the operating process is complex. A new role analyzing method was proposed by generating mappings and using them to provide recommendation for systems. The relation among sets of permissions, roles and users was explored by generating mappings, and the relation between sets of users and attributes was analyzed by means of the concept lattice model, generating a critical mapping between the attribute and permission sets, and making the meaning of the role natural and operational. Thus, a role is determined by permission set and user’s attributes. The generated mappings were used to automatically assign permissions and roles to new users. Experimental results show that the proposed algorithm is effective and efficient.

Category-based statistic language model is an important method to solve the problem of sparse data. But there are two bottlenecks: 1) The problem of word clustering. It is hard to find a suitable clustering method with good performance and less computation. 2) Class-based method always loses the prediction ability to adapt the text in different domains. In order to solve above problems, a definition of word similarity by utilizing mutual information was presented. Based on word similarity, the definition of word set similarity was given. Experiments show that word clustering algorithm based on similarity is better than conventional greedy clustering method in speed and performance, and the perplexity is reduced from 283 to 218. At the same time, an absolute weighted difference method was presented and was used to construct vari-gram language model which has good prediction ability. The perplexity of vari-gram model is reduced from 234.65 to 219.14 on Chinese corpora, and is reduced from 195.56 to 184.25 on English corpora compared with category-based model.

A joint solution model of variable-mass flow in two-phase region and fluid-solid coupling heat transfer, concerned about the charge process of variable-mass thermodynamic system, is built up and calculated by the finite element method (FEM). The results are basically consistent with relative experimental data. The calculated average heat transfer coefficient reaches 1.7×10⁵ W/(m² · K). When the equal percentage valve is used, the system needs the minimum requirements of valve control, but brings the highest construction cost. With the decrease of initial steam pressure, the heat transfer intensity also weakens but the steam flow increases. With the initial water filling coefficient increasing or the temperature of steam supply decreasing, the amount of accumulative steam flow increases with the growth of steam pressure. When the pressure of steam supply drops, the steam flow gradient increases during the maximum opening period of control valve, and causes the maximum steam flow to increase.

The effect of rhamnolipids (RL) on Cd²⁺ adsorption by Penicillium simplicissimum (P. simplicissimum) was studied. The maximum adsorption capacities of Cd²⁺ were obtained at pH 6.0 for the intact P. simplicissimum and at pH 5.0 for the RL-pretreated P. simplicissimum, respectively. The adsorption equilibrium was reached after about 4 h. The experimental adsorption isotherms were in good agreement with the Langmuir model. The maximum adsorption capacities (q_max) for the intact P. simplicissimum and for the RL-pretreated P. simplicissimum were 51.6 and 70.4 mg/g, respectively. The interactions between Cd²⁺ and functional groups on the cell wall surface of the P. simplicissimum were identified by SEM, EDAX and FTIR analysis. It is indicated that carboxyl, amino and hydroxyl groups play major roles in the Cd²⁺ adsorption. The results suggest that the RL-pretreated P. simplicissimum is a promising candidate for the removal of Cd ²⁺ from aqueous solutions.

Iron and steel industry is an important sector of Iran’s economy. Choghart iron ore mine is an important iron ore producer of Iran steel industry. Phosphorous contained in the iron ore concentrates of Choghart mine has a detrimental effect on the steel making process, whereby this causes cracks to form in the refractory lining of blast furnaces. In the past, about 1.43 Mt of low-grade and 4.53 Mt of high-phosphorous materials had been transported to low grade and high phosphorous stockpiles, respectively, for future beneficiation. As a result of the progressive depletion of high-grade ore and establishment of beneficiation plant in Choghart, exploitation of these two stockpiles in this mine became an important issue. In this work, a linear goal programming (GP) model was developed in order to determine the optimum iron ore blend in terms of quality from low grade and high phosphorous stockpiles of Choghart mine. The model was solved by the SOLVER V.9 program. Results show that feeding with acceptable quality (w(Fe)≥50% and w(P)≤1.2%, mass fraction) materials can be blended from stockpiles that satisfy the needs of the Choghart processing line.

Based on the research on rock burst phenomenon induced by the breakage of thick and hard roof around roadways and working faces in coal mines, a criterion of rock burst induced by roof breakage (RBRB) was proposed and the model was built. Through the model. a method calculating the varied stresses induced by roof breakage in support objects and coal body was proposed and a unified formula was derived for the calculation of stress increment on support objects and coal body under different breaking forms of roof. Whilst the formula for calculating dynamic load was derived by introducing dynamic index K_d. The formula was verified in Huating Mine by stress measurement. According to the formula for stress increment calculating, the sensitivities of dynamic load parameters were further studied. The results show that the thickness and breaking depth of roof, width of support object are the sensitive factors. Based on the discussion of the model, six associated effective methods for rock burst prevention are obtained.

Grate process is an important step in grate-kiln pellet production. However, as a relatively closed system, the process on grate is inaccessible to direct detection, therefore, it is hard to control. As a result, mathematical models of temperature distribution, moisture distribution and oxidation degree distribution in pellet bed, with good universality, computation speed and calculation accuracy, are presented based on analysis of heat transfer and physical-chemical reactions during grate process. And real-time visualization of temperature, moisture and oxidation degree distribution in pellet bed during grate process is realized. Model validation is displayed, and the similarity of 91% is proved. The results can reveal real time status on grate, and provide a solid foundation for the subsequent study of artificial intelligence control system of pellet production.

The predictive capacity of numerical analyses in geotechnical engineering depends strongly on the efficiency of constitutive models used for modeling of interfaces behavior. Interfaces are considered as thin layers of the soil adjacent to structures boundary whose major role is transferring loads from structures to soil masses. An interface model within the bounding surface plasticity framework and the critical state soil mechanics is presented. To this aim, general formulation of the interface model according to the bounding surface plasticity theory is described first. Similar to granular soils, it has been shown that the mechanical behavior of sand-structure interfaces is highly affected by the interface state that is the combined influences of density and applied normal stress. Therefore, several ingredients of the model are directly related to the interface state. As a result of this feature, the model is enabled to distinguish interfaces in dense state from those in loose state and to provide realistic predictions over wide ranges of density and normal stress values. In evaluation of the model, a reasonable correspondence between the model predictions and the experimental data of various research teams is found.

The method in which a source is set on the surface and electric potential is received in the borehole is called surface-borehole electric potential technique. Technique of surface-borehole electric potential was employed to study electric response of layered formation. The electric potential was obtained by solving Poisson equation with finite difference method. In the course of calculation, forward modeling with finite difference method was realized by adopting bandwidth non-zero storage technique and the incomplete Cholesky conjugate gradient method. The results show that method of surface-borehole can acquire anomalous electric potential corresponding to geo-electric layers. In addition, application of appropriate mathematical operator can improve the resolution. Moreover, overburden low resistivity layers have severe influence on measuring results of surface-borehole electric potential. However, bottom low resistivity layers play a positive role in the measurement.

The effect of geosynthetic reinforcing on bearing capacity of a strip footing resting on georeinforced clayey slopes was investigated. The results of a series of numerical study using finite element analyses on strip footing upon both reinforced and unreinforced clayey slopes were presented. The objectives of this work are to: 1) determine the influence of reinforcement on the bearing-capacity of the strip footings adjacent slopes, 2) suggest an optimum number of reinforcement and 3) survey the effect of friction angle in clayey soils reinforced by geogrids. The investigations were carried out by varying the edge distance of the footing from slope. Also different numbers of geosynthetic layers were applied to obtaining the maximum bearing capacity and minimum settlement. To achieve the third objective, two different friction angles were used. The results show that the load-settlement behavior and ultimate bearing capacity of footing can be considerably improved by the inclusion of reinforcing layer. But using more than one layer reinforcement, the ultimate bearing capacity does not change considerably. It is also shown that for both reinforced and unreinforced slopes, the bearing capacity increases with an increase in edge distance. In addition, as the soil friction angle is increased, the efficiency of reinforcing reduces.

The mechanical behavior of plastic concrete used in the cut-off walls of earth dams has been studied. Triaxial compression tests on the specimens in various ages and mix designs under different confining pressures have been done and the stress-strain behavior of such materials and their strength parameter changes have been experimentally investigated. It has been observed that increasing the confining pressures applied on the specimens causes the material behavior to be alike the more ductile materials and the compressive strength increases considerably as well. Moreover, a parametric study has been carried out to investigate the influence of essential parameters on the shear strength parameters of these materials. According to the research, increasing the coarse to fine aggregates ratio leads to the increase of compressive strength of the specimens as well as the increase of the cohesion and internal friction angle of the materials. Furthermore, the bentonite content decrease and the cement factor increase result in an increase of the cohesion parameter of plastic concretes and decrease of the internal friction angle of such materials.

Based on Mohr-Coulomb (M-C) criterion, the parameters of Druker-Prager (D-P) criterion for geomaterial were determined under non-associated flow rule, and thus a new D-P type criterion was presented. Two assumptions were employed during the derivation: 1) principal strains by M-C model and D-P model are equal, and 2) the material is under plane strain condition. Based on the analysis of the surface on π plane, it is found that the proposed D-P type criterion is better than the D-P criterion with M-C circumscribed circle or M-C inscribed circle, and is applicable for stress Lode angle less than zero. By comparing the predicted results with the test data of sand under plane strain condition and other D-P criteria, the proposed criterion is verified and agrees well with the test data, which is further proved to be better than other D-P type criteria in certain range of Lode angle. The criterion was compiled into a finite difference package FLAC3D by user-subroutine, and was used to analyze the stability of a slope by strength reduction method. The predicted slope safety factor from the proposed criterion agrees well with that by Spencer method, and it is more accurate than that from classic D-P criteria.

The models of stress corrosion, pressure solution and free-face dissolution/precipitation were introduced. Taking a hypothetical nuclear waste repository in an unsaturated dual-porosity rock mass as the calculation objective, four cases were designed: 1) the fracture aperture is a function of stress corrosion, pressure solution and free-face dissolution/precipitation; 2) the fracture aperture changes with stress corrosion and pressure solution; 3) the fracture aperture changes with pressure solution and free-face dissolution/precipitation; 4) the fracture aperture is only a function of pressure solution, and the matrix porosity is also a function of stress in these four cases. Then, the corresponding two-dimensional FEM analyses for the coupled thermo-hydro-mechanical processes were carried out. The results show that the effects of stress corrosion are more prominent than those of pressure solution and free-face dissolution/precipitation, and the fracture aperture and relevant permeability caused by the stress corrosion are only about 1/5 and 1/1000 of the corresponding values created by the pressure solution and free-face dissolution/precipitation, respectively. Under the action of temperature field from released heat, the negative pore and fracture pressures in the computation domain rise continuously, and are inversely proportional to the sealing of fracture aperture. The vector fields of flow velocity of fracture water in the cases with and without considering stress corrosion are obviously different. The differences between the magnitudes and distributions of stresses within the rock mass are very small in all cases.

The response surface method (RSM) is one of the main approaches for analyzing reliability problems with implicit performance functions. An improved adaptive RSM based on uniform design (UD) and double weighted regression (DWR) was presented. In the proposed method, the basic principle of the iteratively adaptive response surface method is applied. Uniform design is used to sample the fitting points. And a double weighted regression system considering the distances from the fitting points to the limit state surface and to the estimated design points is set to determine the coefficients of the response surface model. Compared with the conventional approaches, the fitting points selected by UD are more representative, and a better approximation in the key region is also observed with DWR. Numerical examples show that the proposed method has good convergent capability and computational accuracy.

Steam-cured condition is found to cause larger porosity and worse properties of concrete compared with normal curing condition. For the sake of seeking effective measurements to eliminate this bad effect of steam-cured condition on concrete, the water sorptivity and pore structure of steam-cured concretes exposed to different subsequent curing conditions were investigated after steam-curing treatment. The capillary absorption coefficient and porosity of the corresponding concretes were analyzed, and their mechanisms were also discussed. The results indicate that water sorptivity and pore structure of steam-cured concrete are greatly influenced by the curing condition used in subsequent ages. Exposure steam-cured concrete to air condition has an obviously bad effect on its properties and microstructures. Adopting subsequent curing of immersing steam-cured concrete into about 20 °C water after steam curing period can significantly decrease its capillary absorption coefficient and porosity. Steam-cured concrete with 7 d water curing has minimum capillary absorption coefficient and total porosity. Its water sorptivity is decreased by 23% compared with standard curing concrete and the porosity is 9.6% lower. Moreover, the corresponding gradient of water sorptivity and porosity of steam-cured concrete both decrease, thus microstructure of concrete becomes more homogeneous.

In order to research the mechanical characteristics of intact Middle Pleistocene Epoch loess, triaxial shear tests and isotonic compression test of intact Middle Pleistocene Epoch loess were conducted by improved SJ-1A triaxial shear equipment. According to test results, it can be found that the intact Middle Pleistocene Epoch loess has the properties of shear dilatancy and shear shrinkage. With the increase of confining pressure, stress-strain curve develops from softening to hardening. The failure mode of intact Middle Pleistocene Epoch loess is shear failure with the rupture angle between 55° and 61°. And it is better to determine the yield stress (p_y, q_y) of the intact loess under different confining pressures by using the ɛ_v-q/p curve. Along with the increase of confining pressure, yield deviatoric stress q_y and yield spherical stress p_y present logarithmic relationship. Besides, the strength parameters, elastic modulus K and G of intact loess, are obtained, which are benefit for loess projects design.