最新刊期
卷 44 ， 期 Z1 ， 2012
- 摘要：Abstract:Mechanical effect and softening effect are two typical effects on underground structures subjected to seepage flow at Karst region. For underground engineering at Karst region with rich groundwater, a finite element method coupling mechanical effect of seepage to simulate excavation and support construction is proposed. And a strength reduction methodology for softening effect analysis of seepage is also put forward based on the identification of the general softening safety factor of underground caverns. The distribution of deformation and damage around openings is calculated and analyzed subjected to different seepage conditions and different softening degrees of rockmass strength. The softening safety factors are identified to quantificationally assess the stability of the caverns related to different calculation conditions and to analyze the impact of softening effect of seepage on the stability of the surrounding rock. The calculation results illustrated with a practical excavation project at Karst region shows that, the displacements around the openings evidently increase when the mechanical effect of seepage is coupled to excavation simulation. It is indicated that the softening effect is of significance on the surrounding rock by comparison of softening safety factors under different seepage conditions. For the underground caverns, the growing of groundwater level would lead to unsteady seepage flow, which has significant impact on the stability of the rockmass. The softening safety factor is able to characterize the effect of seepage on the surrounding rock stability of underground caverns that would be helpful to well design, construction monitoring and safety assessment of underground engineering at Karst region.关键词：underground cavern;Karst region;seepage effect;safety factor;strength reduction;numerical simulation
- 2009
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发布时间：2023-11-14 - 摘要：Abstract:In the construction process of underground tunnels’ three-dimensional finite element simulation, the numerical results are effected by crustal stress and rock mass mechanical parameters. In the process of parameter back analysis, the effect of the crustal stress and rock mass mechanical parameters to the size of stress and deformation is complicated, and it is difficult to use the back analysis to analyze the two simultaneously. Therefore this paper based on the surge chamber of liuping hydropower station that under complicated geological condition, used the three-dimensional finite element back analysis way to analyze the crustal stress and rock mass mechanical parameters in two steps. Firstly, used the regularity of surrounding rock’s deformation to back analysis the crustal stress, selected the median value of the rock mechanical parameters’ reference ranges, obtained the crustal stress’s distribution rule of the calculating model. Secondly, used the back analysis way to analyze the rock’s mechanical parameters, obtained the deformation modulus of the rock’s mechanical parameters of recent fresh surrounding rock，fault，moderately weathered zone，tensely weathered zone were 19Gpa, 0.45Gpa, 4.5Gpa and 2.25Gpa，and the Poisson’s ratio were 0.21, 0.35, 0.25 and 0.30；by comparing the monitoring displacement and the back analysis displacement, it indicated that the average relative error is corresponding with the precision requirement, it can provide reference for similar engineering’s study and analysis.关键词：Complicated geological condition;surge chamber;finite element;back analysis;displacement monitor
- 2186
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发布时间：2023-11-14 - 摘要：Abstract:In order to reveal the creep properties of silty mudstone in Badong Formation strata in the Three Gorges area, the creep test of saturated silty mudstone under triaxial compression was carried out on the RLJW-2000 rock microcomputer-controlled rheology servo test system by step loading method. The confining pressure was 1MPa in the test. Based on the test results, the differences of the creep strain and the creep rate between the axial and radial direction of the specimen under different stress levels were quantitatively studied. The long-term strength of silty mudstone was determined by the test results. The results showed that: (1)The ratio of radial creep strain to radial total strain was always higher than that of axial creep strain to axial total strain under each stress level, so the radial creep characteristics were more significant than the axial creep characteristics for the specimen. (2)The accelerating stage in the radial creep course appeared earlier than that in the axial creep course, and the primary creep rate, steady-state creep rate and accelerating creep rate in the radial creep course was larger than that in the axial creep course respectively for the specimen under the fracture stress level. Therefore, it was more reasonable to determine whether the silty mudstone occurred creep rupture based on the radial creep characteristics of the specimen. The monitoring of radial creep characteristics of the rock should be strengthened in engineering practice, which would be more valuable for the prediction of the failure of rock engineering. (3)The long-term strength of silty mudstone was 74.4 percent of the triaxial compressive strength, so the long-term strength of the rock decreased remarkably. (4)The creep rupture first appeared in the radial direction of silty mudstone, so the long-term strength of silty mudstone obtained in the test was actually the radial long-term strength of the rock.关键词：silty mudstone;triaxial compression;creep test;creep strain;creep rate;long-term strength
- 2353
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发布时间：2023-11-14 - 摘要：Abstract:The slope, where Wangjiaping landslide was located in Longmenshan Town, Pengzhou City, was selected as a typical example of binary structure anti-dip slope with excavation failure in this study, and indoor physical model tests were carried out on deformation and failure under seismic loading. The results showed that the deformation and failure of slope under seismic loading were exacerbated by excavation. As viewed from failure mode, the deformation and failure of anti-dip slope was characterized by both integral sliding of superficial overburden and dump – collapse of anti-dip rocks, consistent with the results of field surveys. The entire process of deformation and failure could be divided into the following phases: the initial stage of earthquake (a gradual connecting process between superficial overburden and bedrock interface), superficial overburden sliding initiation stage, superficial overburden full sliding and bedrock traction - dumping stage. The deformation and failure process and laws of binary structure anti-dip slope were reproduced by the model test.
- 2123
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发布时间：2023-11-14 - 摘要：Abstract:By referring to a high dam project under construction in process, the experimental investigation and theoretical analysis on the variation of hydrodynamic pressure spreading in the base gap with uplift pressure, widths of the contraction joints between slabs and varied destructive degrees of water seal installation has been conducted by considered that any water seal installation between slabs and anchoring on them were all out of function. The study results showed that hydrodynamic pressure spreading in the base gap was larger than uplift pressure when water seal installation was normal. When water sealing was destroyed, hydrodynamic pressure spreading in the base gap increases, but the growth was higher with increase of the value of uplift pressure, and lower with increase of widths of the contraction joints between slabs and destructive degrees of water seal installation within the smaller uplift pressure. When water sealing was destroyed, hydrodynamic pressure spreading in the base gap decreased, but the reduction was higher with increase of the value of uplift pressure, and lower with increase of widths of the contraction joints between slabs and destructive degrees of water seal damaged within the larger uplift pressure. Unreasonable point of the slab safety factor calculated by hydraulic design specification has been analyzed, and uplift pressure was proposed to replace by hydrodynamic pressure spreading in the base gap through analyzing safety factor of slabs in the specification. Drainage measures should be done well in order to ensure normal operation of plunge pool’s drainage system.关键词：inverted-arch pool;hydrodynamic pressure spreading in the base gap;uplift pressure;widths of the contraction joints between slabs;varied destructive degrees of water seal installation
- 1774
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发布时间：2023-11-14 - 摘要：Abstract:Reservoirs have to lower their water level in many cases, such as dam overhaul. To quantitatively study the water quality during the process, the method of numerical simulation was taken in this paper. Firstly, a horizontal two-dimensional unsteady dynamic model and a water quality model for large-scale reservoir were developed, and verified by the field data from a typical reservoir. Then the models were used to predict the impact of water-level decline on the water quality during the dam repair period. The simulation results showed that the concentration of pollution factors increased with the lowering water-level, and decreased with the rising water-level. It was clear that the water quality of reservoir was negatively affected by lowered water-level operation. To reduce the negative impact, the quantity of pollutant entering into the reservoir should be controlled strictly. In addition, water-environmental management and monitoring should be strengthened. The simulation results in this paper have theoretical and practical significance for evaluating water quality impact of lowered water-level operation and water quality protection of reservoirs.
- 2080
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发布时间：2023-11-14 - 摘要：Abstract:Generalized Extreme Value (GEV) distribution model is fitted to the annual maximum rainfall intensity data for Dongguan city and is compared with Log-Pearson-Ⅲ and Gumbel model commonly used in china . The goodness-of-fit test is used to seek among GEV、Log-Pearson-Ⅲ and Gumbel distribution model which fits best. According to the result of test, the GEV distribution model is better than Log-Pearson-Ⅲ and Gumbel distribution model. Horner's equation is common used for deriving storm intensity formula. However, the method is uncertainty and complicated to estimate parameters. There are no explanation solutions for the parameters. So, a new method to derive storm intensity formula by the relationship of the GEV parameters with durations is proposed and compared with the method based on Horner's equation. The result shows that the method is better fit to the observed data. In addition, it is robust and convenient to estimate parameters.
- 3248
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发布时间：2023-11-14 - 摘要：Abstract:The construction of high rockfill dam has a rapid development especially in the last 20 years. These high dams with large storage capacity are located in a complex geological environment.All these projects whose slopes are precipitous are large-scale projects and would lead to serious consequences for accidents,the problem that how to effectively use its safety monitoring informations, and control its working state in-time and scientifically to ensure the safe operation of the dam is related to people's livelihood.Based on the prototype monitoring data series of Yele asphalt concrete core rockfill dam and 3-D finite element calculation results, the gray aging model of GM(1,1,t) was applied to displacement hybrid-model of high earth-rock dam for the first time.The displacement hybrid-model established was applied to Yele rockfill dam.The results shows that the displacement hybrid model has a high precision and an effective prediction，which can meet the engineering requirements.Moreover, the model factor of this kind of model has a definite physics meaning,and the convergence and divergence of aging displacement components may be judged easily,and the dam can be monitored highly contrapuntally. The model has some reference value for model research of same dam.关键词：high earth-rockfill dam;deterministic model;grey model;displacement hybrid-model
- 2119
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发布时间：2023-11-14 - 摘要：Abstract:Since it was difficult to observe the process of flocculation and settling for cohesive fine sediment, this paper presented a model for the flocculation and settling process of cohesive fine sediment in still water, and checked the model with previously published data. At last, temporal and spatial variation of volume distribution and average diameter of flocs were studied through a series of simulated experiments, as well as the impact of fractal dimension on this model. The results revealed that the volume of large flocs and average diameter of flocs appeared the trend from increasing to decreasing as time increased, but with the depth increasing, the range of floc volumes broadened, the ratio of large flocs increased, and the maximum of average diameters became larger with appearing early. The effect of sediment transport in vertical direction became stronger as the fractal dimension increased.关键词：cohesive fine sediment;simulation;flocculation;settling;temporal and spatial variation
- 2826
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发布时间：2023-11-14 - 摘要：Abstract:Regional debris flow risk assessment is an important part of debris flow prediction and mitigation. It is also an important tool to pre-assess potential hazards, which involves the natural characteritics of hazard. Therefore regional debris flow risk assessment is a complicated but important scientific problem. Traditional assessment methods, which contain empirical weight value for the influence factors, are difficult for calculation and application in regional debris flow risk assessment. In this paper, the Set Pair Analysis (SPA) has been introduced into the relation analysis of regional debris flow risk assessment variables because it doesn’t need the empirical weight value and the connection degree of SPA can display the detail related structure of debris flow risk assessment variables. Then, the basic ideals and steps of SPA are discussed. Finally, an application of the proposed SPA method to Beichuan county, provides high accuracy and reasonable risk estimates. The results also show that the present method is simple in concept, convenient to calculate and feasible for application.关键词：debris flow;set pair analysis;connection degree;risk assessment;assessment index
- 3179
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发布时间：2023-11-14 - 摘要：Abstract:A depth-averaged finite difference two-dimensional hydrodynamic-morphological and sediment transport model is presented in the orthogonal curvilinear grid system. Based on the previous work, the influence of selective sorting is taken into account in the sediment model by modifying the sediment transport capacity; the grain size distribution is simulated according to the sediment mass conversation equation for bed surface. The model is applied to the experiment on downstream fining by seal. The simulated bed profile and grain size distributions are in acceptable agreement with the field measurements. It illustrates the capability of the two dimensional models in predicting the river morphology and grain sorting processes for actual rivers.关键词：river topography;selective sorting;composition of bed material;2D numerical model
- 1990
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发布时间：2023-11-14 - 摘要：Abstract:Effect of the acute toxicity of total dissolved gas (TDG) supersaturation on crucian (carassius auratus) was investigated by rheobiotic testing in order to determine effect of TDG saturation on crucian, as well as effect of catalase (CAT) activity. The results showed that the value of LC50 of the first test group are 150.7, 139.2, 137.9 and 136.2% corresponding to exposure time in TDG supersaturated water of 8,10,11 and 14h respectively. And the value of LC50 of the second test group are 142.1%, 141.2%, 139.0% and 134.7% corresponding to exposure time in TDG supersaturated water of 9, 10, 11 and 15h respectively. The activity of catalase (CAT) in crucian’s gill and muscle increases first and then decreases when crucian were exposed to water with TDG saturation level was 145%. It was revealed that the activity of catalase in crucian’s muscle tissues is lower than in gill tissues.关键词：TDG Supersaturation Crucian(Carassius auratus) Toxic effect Catalase(CAT)
- 2211
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发布时间：2023-11-14 - 摘要：Abstract:Bolting support is widely used in the underground engineering due to its many advantages. In this paper, implicit bar elements and shell elements are used to simulate rockbolts and shotcrete layer respectively, the three-dimensional nonlinear finite element technique has been used to analyze the effect of bolting support in Rong-Ge underground powerhouse engineering. The influence of bolting support on the stress,deformation as well as plastic zones of surrounding rock have been recognized through calculation. The overall stability factor of Rong-Ge underground powerhouse is obtained by using the strength reduction method and the effect of bolting support on the overall stability can be recognized. The bolting support can effectively limit the development of deformation and the plastic zone of the surrounding rock, improve the stress state of surrounding rock, and avoid stress concentration in a certain extent, as well as make the stability safety coefficient raised from 1.8 to 2.5, improve the overall stability of underground powerhouse effectively.关键词：underground power-houses;bolting support;stability of surrounding rock mass;stress and deformation;plastic zones
- 2376
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发布时间：2023-11-14 - 摘要：Abstract:Two dimentional simplified (including kinematic wave and diffusion wave) and full hydrodynamic models have been widely applied to the study of flash floods. However, there are still few guidelines to help modelers to select an apropriate model for flash flood simulation on field scale. This paper, firstly, presented a comparative study of simplified and full hydrodynamic models in terms of physical basis. Then, the models were applied to unsteady flow with lateral inflow, experimental rainfall-runoff and a field study case in Sanjia village respectively to explore their stability and applicability. The results showed that differences in theoretical basis results in differences of limitations in applicability and accuracy in simulation: even under the calibration of Manning roughness, the simplified hydrodynamic models were invalid for simulating the rainfall-runoff on experimental scale and were unsuitable for modeling on field scale like Sanjia village study case. The full hydrodynamic model was needed for the accurate simulation of flash floods.
- 2369
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发布时间：2023-11-14 - 摘要：Abstract:There is widely distributed loose wide grading gravelly soil in triggering area of debris flow. It contains many materials, such as the clay, silt, sand, gravel and so on. Debris flow will be triggered by the effects of fine grain movement. On the basis of the above, 16 groups of artificial rainfall flume tests are designed using orthogonal theory, of which slope gradient, rainfall intensity and rainfall time are considered as influential factors. Taking the increment of fine grains as the evaluation criteria and analyzing the 3 factors by means of range，variance and regression, the characteristics of movement of fine grains and its effects can be obtained. The results show that artificial rainfall flume tests can be greatly reduced in terms of orthogonal principle design. Among 3 influential factors to the effect of fine grain movement, the rainfall time is the most important one, followed by the rainfall intensity and slope gradient. And the rainfall time and intensity play a decisive role. The statistical relationship of increment of fine grains (y) and controlling factors rainfall intensity (x1) and time (x2) can be described asy=[40.92-0.83x(1)-0.0045*x(1)^2-8.12* x(1)^3+81.26*x(2)]/[1-0.42*x(1)+619.8*x(2)]. It can provide a reference to the deep research for the effects of fine grain movement on the initiation of landslide and debris flow.
- 2184
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发布时间：2023-11-14 - 摘要：Abstract:Element stress of slope soil is derived from the stress equilibrium differential equations under the plane strain condition. The water-drop type yield surface function is modified in consideration of soil reinforcement by roots. Visco-plasticity model is used between velocity and the visco-plastic strain of the slope soil. The explicit expression of the deformation rate with the depth of slope soil is thus derived. Simulation accuracy is improved by modifying the viscosity with the depth of slope soil. Finally, numerical example is given in comparison with the field measured data and good agreement is achieved.关键词：Visco-plastic strain rate, soil reinforcement by roots, water-drop type yield surface, viscosity, analytical solution.
- 1826
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发布时间：2023-11-14 - 摘要：Abstract:In order to investigate the effect of the principal stress orientation on tunnel stability, the whole process from initial damage to complete failure of rock is investigated through the methods of experiment and numerical simulation. In the numerical study, the maximum tensile strain criterion is adopted, and accordingly a equivalent stress is defined. The equivalent stresses at the points around the tunnel are calculated, and the results are in good agreement with the experimental results. The results show that the initiation and propagation of cracks occur mainly along the direction of principal stress; the failure patterns vary as principal stress orientation changes. The maximum failure stress appears as the angle between the major principal stress and the tunnel is about 60°, and the minimum appears as the angle between the major principal stress and the tunnel is near 45° or near 90°.关键词：tunnel;principal stress orientation;model experiment;numerical simulation;stability
- 2220
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发布时间：2023-11-14 - 摘要：Abstract:Underground rock naturally contains pre-existing joints treated as cracks or flows in facture mechanics, which will directly weaken the strength of rock, and may induce mining accidents, such as rock burst. In the paper, a nondestructive, whole-field, graphic stress-analysis experimental technique, photoelasticity, is applied. The cracks investigated is situating inside the surrounding rock mass of a tunnel, and the effect of the position and orientation of cracks on stress intensity factor (SIF) is studied by using the information of principal stress difference and principal stress direction at every point in the domain. The results show that: (1) For the specimen under uniaxial compression, SIF increases as the crack angle with the horizontal axis increases from 0°to 60°and it decreases from 60°to 90°; (2) For the specimen under biaxial compression, when the crack orientation is 45°, the crack SIF is the maximum, which indicates 45°is the most unfavorable crack orientation.关键词：tunnel surrounding rock;crack;photoelasticity;stress intensity factor
- 2060
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发布时间：2023-11-14 - 摘要：Abstract:A series of falling head hydraulic conductivity tests were performed on natural Wenzhou clays consolidated at different stress levels using modified oedometric apparatus to investigate the change law of hydraulic conductivity of natural clays during compression. It is found that both the compression behavior and the hydraulic conductivity behavior are significantly affected by the yield stress caused by the soil structure formed during the depositional and post-depositional processes. When the consolidation pressure is less than yield stress, the compressibility is small and the variation of hydraulic conductivity is not obvious; when the consolidation pressure is larger than yield stress, the compressibility increases dramatically and the hydraulic conductivity varies clearly with the stress level. The change in hydraulic conductivity with the increase in stress level is discussed, and a method of predicting hydraulic conductivity during compression is proposed.关键词：natural clays;hydraulic conductivity;compression process;yield stress;stress level
- 2623
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发布时间：2023-11-14 - 摘要：Abstract:An element of anchor cable was developed in order to accurately simulate multi-anchorage effect. And the effect of anchor cables on slope stability was analyzed. Based on the topographic map of a hydropower dam site and the distribution of anchor cables, a 3D geology model with anchor cables was constructed (model I). The interaction of the anchoring segments and surrounding rock was treated with coupling. And the actual tension was applied on each anchor cable. Then another model without anchor cables was also constructed for comparison, named as model II. Both models were analyzed during construction process. The results showed that the node displacements of model I were consistent with the corresponding monitoring data of the multi-displacement meters. The displacements in most part of the slope in model I were lower than those in model II. On 1730m foundation platform, the displacements in model I reduced to 1/3 of those in model II. The element could effectively simulate anchor cables with high accuracy. The slope was more stable with anchor cables.关键词：anchor cables;multi-anchorage effect;high slope;finite element method;slope stability
- 1954
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发布时间：2023-11-14 - 摘要：Abstract:A large number of staircase damages in reinforced concrete frame structures had absorbed much concern during 2008 Wenchuan Earthquake. In order to fully investigate the interaction mechanism and failure modes between the staircase components and surrounding frame members, a static monotonic test on a one story two bay RC frame structure with staircase under the lateral loading was carried out. The experimental results indicated that the distribution of internal force in staircase components under the lateral loads was significantly different from the traditional design methodology in which only gravity loads are involved. The staircase can noticeably increase the lateral stiffness of overall structure but introduce the torsion effect as well. In general, the staircase experienced the damage earlier and much severe than the main structure. It is specifically concluded as follows: the flights were under the combined action termed the axial force, biaxial bending moment and biaxial shear force; the joint of flight and landing beam may become one of the most attacked parts by lateral force; the mid-span of landing beam was suffered the unexpected higher negative moment; the punching failure may occurred at the mid-span of platform and landing beam due to the K-braced effect from the flights.关键词：staircase;static monotonic test;failure mechanism;reinforced concrete frame;lateral stiffness
- 1989
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发布时间：2023-11-14 - 摘要：Abstract:The existence of cracks significantly affects the mechanical property of materials. In order to investigate the stress intensity factors of Y shape cracks, experimental and numerical studies are implemented in this paper. The calculation results show that the isochromatic fringe loops around the cracks of the two ends are basically symmetrical. As the branch angle of the Y shape cracks increases from 0o to 90o, the stress intensity factor of the major crack change slightly, however, the stress intensity factor KI of branch cracks continually decrease, and the KII first increase and then decrease gradually. The maximum value of KII occurs between 45o to 60o. This paper also analyzed the lateral confining stress effect on the branch cracks, and the result shows that KI of the branch cracks increases with the increase of the lateral confining stress, but KII continually decrease with it until to zero.关键词：branch crack;photoelastic experiment;crack angle;lateral confining stress;stress intensity factor
- 1725
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- 2
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发布时间：2023-11-14 - 摘要：Abstract:Abstract: The stress distributions of the temporomandibular joint(TMJ) under centric occlusion, anterior occlusion and unilateral occlusion were analyzed. A three-dimensional finite element model of the TMJ with mandible and teeth was developed according to CT images of a volunteer with asymptomatic joints. Contact elements were used to simulate the interaction between the articular discs and the mandibular condyles and between the articular discs and the articular fossas. The muscle forces and boundary conditions corresponding to the three occlusions were applied on the model. It was observed that the stresses of the TMJs in the models with anterior occlusion and unilateral occlusion were higher than those in the model with centric occlusion. In the three models, the maximum and minimum stresses of the discs occurred in the intermediate zones and the anterior bands, respectively. Moreover, the stresses on the ventral disc were higher than the dorsal disc. The high stresses of the discs were located at the intermediate zones under the three occlusions. The stress of the contralateral TMJ was much higher than the ipsilateral TMJ under the unilateral occlusion.关键词：temporomandibular joint(TMJ);finite element method;stress analysis;occlusal force;contacts
- 2055
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- 2
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发布时间：2023-11-14 - 摘要：Abstract:To gain an insight into the explosion behavior of coal dust-inertant mixtures, systematic experiments were carried out on explosion severity (the maximum explosion pressure, the maximum rate of pressure rise and the combustion duration), sensitivity (the higher and lower explosion limits) and inertant inerting effectiveness by using a Siwek 20 L spherical explosion test system. Influences of ignition energy, coal dust calorific value, inertant composition, dust concentration and mixing ratio of coal/inertant were taken into account. Results show that the addition of inertant into the coal dust can mitigate the explosion brisance effectively. The inerting effectiveness of inertant decreases with ignition energy and becomes stabilized when ignition energy exceeds to 5 kJ, which suggests that the ignition energy region of 5-10 kJ be appropriate for inerting testing. The inerting effectiveness of inertant is reversely related to coal dust calorific value. For the inerting of coal dust explosion, the moisture shows the best result, followed by the Monoammonium phosphate and calcium carbonate. The inertant amount required for fully inerting is related to the coal dust concentration and when the coal dust concentration reaches to the worst-case concentration (between 200-400 g/m3), the maximum amount of inertant will be required. It is also found that the addition of inertant reduces the higher explosion limit and raises the lower explosion limit of the coal dust, leading to a narrowed explosible concentration region.关键词：coal dust;dust explosion;inerting;ignition energy;the worst-case concentration
- 2267
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发布时间：2023-11-14 - 摘要：Abstract:Study used Green house gas CO2 to remove sodium from the aluminum solid waste Bayer red mud. Analysis of the particle size of red mud, reaction time, and stirring rate of the red mud slurry three dynamics factors’ effect to the sodium removal rate was given. The results were as follows. The particle size of red mud’s effect to the sodium removal rate was very significant, with other factors’ effects not. The optimal parameters for the sodium removal were red mud particle size 2000mesh, reaction time 90min, and stirring rate 600r/min; Under optimal parameter condition, the sodium removal rate was 77.39%, and the remaining Na2O content was 2.37%. The diffusion of compounds containing sodium was the restrictive factor for the sodium removal in the red mud slurry, and the smaller particle size of red mud was better for the diffusion of compounds containing sodium. The red mud particle size should be considered fine grinding to 2000mesh during the afterward sodium removal technique research.关键词：Bayer red mud1;carbon dioxide2;the sodium removal rate3;dynamics4
- 1585
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发布时间：2023-11-14 - 摘要：Abstract:Mean activity coefficients of NaBr in NaBr-Na2B4O7-H2O system had been determined in the ionic strength ranging from 0.01 to 0.50 mol/kg at 298.15K by the EMF method. The mean activity coefficients were compared with those ionic strength scores of Na2B4O7 in the mixture solution. The results show that the determination of the mean activity coefficients of NaBr is reliable and the mean activity coefficients of NaBr increase with increasing of the ionic strength scores of Na2B4O7 in the mixture solution in the ionic strength range from 0.01 to 0.50 mol/kg.Pitzer ion interaction parameters that were not reported were evaluated from present measurements of the mean activity coefficients of NaBr.关键词：EMF method;Activity coefficients;Ion selective electrode
- 2
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发布时间：2023-11-14 - 摘要：Abstract:Collagen fiber, cross-linked by glutaraldehyde, was used as adsorbent for the chromatographic separation of flavanone glycosides and aglycones from their mixture. Naringin and hesperidin were selected as the representative of glycosides, while naringenin and hesperetin were the representative of aglycones. It was found that the mixture of flavanone glycosides and aglycones could be well separated by stepwise elution of hexane-ethanol and ethanol-water solutions, and the recovery extent of all products was higher than 90%. In addition, the mixtures can be well separated only using ethanol and water as elution agents if the column length of collagen fiber adsorbent was long enough. The separation capability of collagen fiber adsorbent was not obviously reduced after 5 times of repeated applications with a purity higher than 96% and recovery higher than 90%, exhibiting great reusability. Therefore, the collagen fiber adsorbent can be used for the effective separation of flavanone glycosides and aglycones mixture.关键词：Collagen fiber;collagen adsorbent;flavanone glycosides;flavanone aglycones;chromatographic separation
- 1954
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发布时间：2023-11-14 - 摘要：Abstract:Coupling with the technology of photocatalysis and organic membrane separation, a new type of three-phase fluidized bed recycle reactor equipment of photocatalysis-organic membrane separation was designed, and the TiO2 distribution properties in the recycle reactor equipment, which the average diameter is 0.22 μm, were investigated. The results show that TiO2 suspension concentration in the membrane separator is much lower than that in the photocatalytic reactor. As the aeration flux in the bottom of the photocatalytic reactor and the TiO2 dosage are fixed, the equilibrium concentrations of TiO2 suspension remain constant, and the optimal values of the dosage and the flux are 82.50 g, 1.00 m3/h respectively. The water rinsing in the recycle pipe makes the TiO2 suspension concentrations invariable, and the best rinsing time intervals is 60 min. The TiO2 suspension concentration with the 6.50 mm of connecting pipe diameter is lower than that of the 20.00 mm in the membrane separator. The membrane effluent has very small influence on the TiO2 distribution properties.关键词：Photocatalytic oxidation;membrane separation;TiO2 distribution property;Recycle reactor equipment
- 1723
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发布时间：2023-11-14 - 摘要：Abstract:In order to make use of the recycled aggregate concrete from the collapsed structures in Sichuan earthquake on 12 May 2008, ten short steel tube columns filled with normal concrete and recycled aggregate concrete (RAC) were fabricated and tested to investigate the effects of the load carrying capacity, deformability and stiffness of the steel tube columns reinforced by carbon fibre reinforced polymer (CFRP) sheets. The main experimental parameters included the portion of the recycled aggregate concrete used, the cross section type of the columns, the reinforcement ratio of CFRP and the length to diameter ratio. The results show that the ultimate load carrying capacity and deformability of the short columns could be increased greatly by two reinforcing arrangement, i.e. full wrapping arrangement and partial wrapping arrangement. The results also show that the more of CFRP reinforcing ratio, the higher of ultimate load carrying capacity and deformability, but the enhancement ratio is not in proportion to the CFRP reinforcement ratio. In addition, the stiffness of the steel tube columns strengthened was enhanced more significantly in the columns with full wrapping arrangement than that of with partial wrapping one. Finally, the result indicated that the length to diameter ratio had a little influence on the load carrying capacity of the steel tube columns with CFRP reinforcement.关键词：CFRP;RAC filled steel tube columns;mechanical property;experimental research
- 1912
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发布时间：2023-11-14 - 摘要：Abstract: Thermal residual stresses in two models of TiC coating cemented carbide with and without a gradient layer were calculated using the finite element method. Effects of different thickness of coating and gradient on residual stress were investigated. The results show that: residual stress in TiC coating layer decreased more than10% , the reductions of residual stress in alloy are more than 30% when the composites have gradient layer, surface residual stress also declined significantly; The tensile stress in coating layer fell significantly with increasing coating thickness, the shear and Von Mises stress increased slightly (coated gradient cemented carbide’s Von Mises stress dropped); With the increasing thickness of gradient, the residual stress of the coating decreased, when the thickness of gradient is too large, stress didn’t change no longer. Therefore, by selecting appropriate thickness of coating and gradient layer (thickness of coating: 5 ~ 8μm, thickness of gradient about 20μm), can effectively ease residual stress and increase the bond strength of materials.关键词：finite element method,coatings,gradient cemented carbide, thermal residual stress
- 1822
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发布时间：2023-11-14 - 摘要：Abstract:To study the fractal evolution laws of particle breakage for gypsum granular materials under loading, three kinds of stress path tests were conducted with the triaxial apparatus. The stress path included the constant confining pressure, constant mean principal stress and isotropic consolidation pressure. The grain size distributions of gypsum granular materials after tests were analyzed by sieving. It was found that the degree of particle breakage for gypsum granular materials under loading increased with the increase in initial confining pressures. The grain size distributions after breakage present the fractal. The relationship between the fractal dimension of grain size distribution and the confining pressure/mean principal stress can be simulated by hyperbolic curves. The asymptotic value of the fractal dimension is about 2.5. The fractal dimension increases linearly with the increase in the relative particle breakage, and it can also be referred to as a parameter describing the degree of particle breakage for granular materials.关键词：gypsum;particle breakage;stress path;fractal
- 1826
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发布时间：2023-11-14 - 摘要：Abstract:The vacuum brazing of Ti(C,N)-based cermets and 3Cr13 stainless steel was conducted by using AgCuZnNi alloy as filler metal. The effects of brazing temperature and holding time on the shear strength of the Ti(C,N)-based cermet/3Cr13 stainless steel joints were investigated. The microstructure, areal distribution of elements and fracture morphology of the joints were examined by SEM and EDS. Results show that the shear strength increases firstly and then decreases with increasing of the bonding temperature or holding time. The maximum shear strength is achieved to be 154 MPa when the brazing temperature is 820℃and holding time is 10 min. The Ti(C,N)-based cermet/3Cr13 joint mainly consists of Ag (s.s.) and Cu (s.s.). Ag (s.s.) mostly exists in the middle of the brazed joint, while Cu (s.s.) is located in the two sides of the brazed joint and adjacent to parent metal. Fracture mainly happens at the side of Ti(C,N)-based cermets and the fracture mode is brittle fracture.关键词：Ti(C,N)-based cermets;brazing;shear strength;microstructure
- 1593
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发布时间：2023-11-14 - 摘要：Abstract: Evaluation on shear capacity of Corroded Reinforced Concrete Beam (CRCB) is the important part of reliability and durability assessment of existing buildings. The main factors related to shear capacity of the corroded reinforced concrete beams were investigated based on the deterioration mechanism of shear capacity. The barriers to evaluating the shear capacity of CRCB validly were discussed. Validation was conducted according to the existing testing data to assess the current shear capacity models. The corrosion degree of reinforcements cannot objectively reflect the nature of corrosion pit based on current mean expression of the corrosion ratio of reinforcements in which localized corrosion is not highlighted and stress concentration is not involved. The nominal stress or nominal strength cannot reveal the natural mechanical properties of corroded reinforcement. Localized corrosion and corrosion expansion need to be taken into account to investigate the bonding properties between corroded reinforcement and concrete. The existing shear capacity models of CRCB are applicable to some extent, however, all of them were proposed based on inadequate testing data or theoretical analysis.关键词：corroded reinforcement;mechanical properties;bond properties;shear capacity;reinforced concrete beam
- 1733
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发布时间：2023-11-14 - 摘要：Abstract:WC–8Co powders after different milling time were sintered by spark plasma sintering at the different temperature. The influence of the milled time and sintering temperature on the microstructure and mechanical properties of hard alloy were investigated. The results showed that when the milling time was prolonged, the powder particles became smaller, the lattice distortion of WC grain increased, and the diffraction peak intensity decreased. Meanwhile, the longer milling time was, the more the aggregated powders were; the sintered samples can be close to full density using spark plasma sintering at 1200 ℃, which was lower than the sintering temperature of traditional method; when the milling time was 2h, the density, hardness and fracture toughness of the sintered samples were best, and the grain was smaller and evenly distributed; when the milling time was 4h, the properties deteriorated rapidly, and the microstructure existed more coarse grains，pores，Co pools and other defects.关键词：hard alloy;WC-Co;spark plasma sintering;milling
- 1613
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发布时间：2023-11-14 - 摘要：Abstract:Abstract: In this article, the effects of extrusion ratio on the corrosion resistance of 6061 aluminum alloy in different condition, were studied. The anti-corrosion was evaluated with weight-loss method and potentiodynamic polarization curve, the micro-morphology was analysed with optical microscope and SEM. The results show that, grains of 6061 aluminum alloy become finer with extrusion ratio increasing(18，23，25), The ply of anodic oxidation film of 6061 aluminum alloy，produced by anodic oxidation，become thicker with extrusion ratio increasing. After immersion in 3% HCl solution, corrosion resistance of 6061 aluminum alloy, without anodic oxidation process, improve with extrusion ratio increasing. The anodic oxidation film of 6061aluminum alloy, produced by anodic oxidation, is much more likely to be damaged in higher extrusion ratio, so the corrosion resistance become worse. In 3.5% NaCl solution，the corrosion resistance of 6061 aluminum alloy, without anodic oxidation process, decreasing with extrusion ratio increasing. The higher extrusion ratio lead to thicker ply of anodic oxidation film of 6061 aluminum alloy, the Cl- can be protected more widely from corroding 6061 aluminum alloy, so the corrosion resistance will increase obviously.关键词：6061 aluminum alloy;extrusion ratio;corrosion resistance;grain refinement
- 1801
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发布时间：2023-11-14 - 摘要：Abstract:The present pilot study aims to construct a possible optimal angiogenesis model in vitro on fibrin gel for tissue engineering. We mixed fibrinogen and thrombin to form fibrin gel that contained no stimulatory factors as a culture substratum, and then endothelial cells (HUVEC) as the model cell line were seeding on the fibrin matrix to develop a test model. The development of tube-like structure (TLS) was examined in-situ with a phase-contrast and the length of it was calculated by software. Results showed that tubular structure formed within 24 h on proper concentration of fibrinogen, which was also sensitive to the other surrounding environment (i.e. concentration of thrombin, blood serum and HUVEC). Furthermore, the TLS were formed more favorable for the concentration of fibrinogen (0.5mg/mL), thrombin (0.1 U/mL), blood serum (10%) and HUVECs (1.5mg/ml). The simplicity, reproducibility of the fibrin-based model described here is a useful in vitro angiogenesis model for the further study of tissue-engineering vascularization.关键词：In vitro angiogenesis;Tubular structure;Fibrin;model construction
- 1532
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发布时间：2023-11-14 - 摘要：Abstract: In order to research the effects of different heat treatment processes on mechanical properties of 34CrNi3Mo cast steel, the mechanical properties were compared in the condition of four kinds of heat treatment technologies which were “water spraying quenching with high temperature tempering”, “oil quenching with high temperature tempering”,“dual fluid quenching (water-oil)with high temperature tempering” and “dual fluid quenching with two times high temperature tempering”. The results show that not only the casting processed by “water sprying quenching with high temperature tempering” has better strength and hardness than that processed by “oil quenching and high temperature tempering”, but also has greater plasticity and impact toughness. The characteristics of strong external part and toughness internal can be achieved with “dual fluid quenching with high temperature tempering”. Dual fluid quenching (water-oil) and then twice high temperature tempering make the strength and hardness of the casting higher, but the plasticity and toughness get decline.关键词：34CrNi3Mo;quenching;tempering;microstructure;mechanical properties
- 1722
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发布时间：2023-11-14 - 摘要：Abstract:One of the important decision-making tools is mid-term conflict detection (MTCD) in air traffic control system. The accelerating algorithm using CUDA technology on graphics processing units(GPU) was proposed to improve the accuracy and speed of Prandini MTCD approximate randomized algorithm. The algorithm was redesigned and optimized using multi-thread parallel processing capability of CUDA and computation capability of GPU. The experiments validated that the algorithm can obtain more than 50-fold speedup compared with an Intel core2 CPU by using NVIDIA Geforce 8800 GTS. This approach can satisfy with the real-time and high accuracy requirements of big air traffic Area Control Center system.关键词：air traffic control;flight conflict;mid-term conflict detection;GPU;CUDA
- 2
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- 1
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发布时间：2023-11-14 - 摘要：Abstract:With no prior knowledge of the cluster number in complex networks, the clustering for complex networks not only needs to determine the number of clusters, but also to correctly assign nodes into their clusters. However, most traditional methods cannot automatically resolve the number of clusters. To solve the problem, a novel algorithm: AutoCNC-GEP, is proposed for complex network clustering by cohesion superiority of GEP and the information-theoretic topology compression framework. Both of the chromosomal structure and special genetic operations are designed for complex network clustering, and a concept of partial clustering is proposed. By adopting either Map Equation or Modularity as fitness function, AutoCNC-GEP is tested on real network data. The experiment results show that AutoCNC-GEP not only self-adaptively resolves the number of clusters, but also accurately assigns nodes into their right clusters with no prior knowledge of the number of clusters in complex networks.关键词：complex network clustering;map equation;gene expression programming
- 2082
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发布时间：2023-11-14 - 摘要：Abstract: This paper presents a novel combination of Curvelet and Wavelet algorithm for SAR image speckle noise reduction. In this paper, Smooth areas and edges of SAR images are distinguished and labeled by 16 direction detection template. Respectively, using improved soft threshold curvelet and wavelet transform method to process Smooth areas and edges. Finally，a complete noise reduction image generated by the combination of two noise reduction result. Comparison with existing combination methods(CFA、ACM), new combination method have some improvement in various indicators, such as PM, ENL, etc. Experimental results show that the approach compared to existing methods that can not only effectively remove speckle noise, but also can better maintain the image edge information.
- 1784
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发布时间：2023-11-14 - 摘要：Abstract:The ratio of positive cells in histopathology image affects definitively diagnosis and classification of cancer. In allusion to complex color and texture, fuzzy boundary in histopathology image, this paper proposed a new algorithm of positive cells contour detection for cells counting, which combined RGB channel extracting and image binaryzation to separate positive cells, and have high efficiency in contour detection of these cells base on CV model. Experiment demonstrates that, the algorithm solves the problem of weak boundaries that can`t achieve in traditional way, and on the premise of maintaining the efficiency of algorithm, this method can separate the positive cells and detect its contour automatically.关键词：histopathology image;positive cells separation;contour detection;CV model
- 2136
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发布时间：2023-11-14 - 摘要：Abstract:To overcome the common difficulties emerging in video surveillance, a random sampling background modeling algorithm is presented. Unlike other background algorithm, the random sampling method denotes the background model by using a set of sampling pixels of different time located at a specific position. When deciding whether a new coming pixel belong to background or not, each pixel in the model is compare with the new pixel. If there are enough samples similar to the pixel, it is judged as background pixels. And then, this pixel is used to update the model samples selected out randomly. Thanks to the attributes of random sampling, this algorithm exhibits excellent ability in resisting gradual and sudden illumination changes, dynamic background, camouflage, shadows and video noise. The implementation is completely describes in this paper, and experiments indicate that the random sampling modeling method has higher computing efficiency and percentage of correct classification.
- 1520
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发布时间：2023-11-14 - 摘要：Abstract:Fire and other irregular objects is variability in space and time, this make the simulation of such objects become a difficulty problem of graphics. The traditional method of efficiency and authenticity is not satisfactory,this paper propose an interactive fire simunlation based on fabric model.First analyzed the principle which used the simplex noise to simulate,then used fabric model to drew low-frequency information of fire,through a GPU-based fast methods improve efficiency. Experiments show that, all these measures contribute to reach a desirable realtime simulation speed and acquire an improvement of performance,also can interact with different wind field.
- 1898
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发布时间：2023-11-14 - 摘要：Abstract:Considering of the distortion caused by the accumulative error in multiple core fluorescence image stitching, we proposed a global optimization methods based on L-M(Levenberg—Marquardt) algorithm. In order to achieve global registration, which can minimize the sum of error distance for all feature point after spherical transforming in all image, we based on the initial parameters of the spherical projection for each image and used L-M algorithm to do iterative calculation;during the iterative calculation,the damping parameter μ will be real-time adjusted due to the gain ratio δ so that we can continuously update the iteration direction and the size of step, find the optimal set of projection parameter. The algorithm is applied to the multiple core fluorescence images stitching ,solved the problem that the distortion of stitched image caused by the accumulative error, to obtain satisfactory results.关键词：core fluorescence image;global registration;Levenberg-Marquardt algorithm;accumulative error
- 2256
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发布时间：2023-11-14 - 摘要：Abstract:The determination of pore body and pore throat distributions is presently the most challenging task for predicting the transport and capillary properties of porous media. Silin present a robust approach to study the morphology of the pore space. One of the distinctive features of the algorithm is that no image thinning is applied. This paper analyzes the drawbacks of the maximal ball algorithm，more throats than intuitive judgment and geometrical approach cause inaccurate information, and modified them. The pore space is firstly partitioned into constituent pores, and then the information of pores and throats are calculated. Finally the methods of statistics and morphology are used to remove the over segmented throats. The algorithm has been tested on the images of computer-generated and natural sandstones. The results of improved algorithm are consistent with that by the visual apperception.关键词：pore structure;throat segmentation;maximal ball
- 1746
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发布时间：2023-11-14 - 摘要：Abstract:Ultrasound image retrieval will play an important role in routine diagnosis of breast lesions. A novel method for content-based retrieval of breast tumor ultrasound images was proposed. The image characters on shape, texture, and boundary were quantified by 3 interpretative features, namely lifting wave entropy, fitting ellipse overlap ratio and 2-dimensional polar coordinate boundary descriptor. Then similarities were calculated by the use of these 3 features and a graded retrieval scheme was carried out. Data from 126 patients with biopsy-proven benign and malignant masses were used to evaluate the retrieval performance of the proposed method. The pathological accuracy of the retrieval output was 90.79%. This satisfying result indicated that the functional graded retrieval scheme with only 3 features was capable of aiding diagnosis of breast diseases.关键词：content-based retrieval;breast ultrasound images;computer aided diagnosis
- 1884
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发布时间：2023-11-14 - 摘要：Abstract:The membership is used in the standard Fuzzy c-means algorithm for image soft segmentation, especially for the image with blur edges. FCM is not suitable for the low contrast and noisy infrared image. In order to achieve the correct segmentation, a new algorithm is proposed. First step is removing noise by the NSCT. The next step is clustering by the modified FCM. The data is mapped to non-linear space for easy clustering by kernel function. The neighborhood information is used for correcting the membership of every pixel. Experiments result has been show that the algorithm has higher accuracy and better segmentation quality than others.关键词：fuzzy clustering;segmentation;kernel
- 1970
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发布时间：2023-11-14 - 摘要：Abstract:In order to improve the performance of mobile positioning, enhance the Beidou navigation system application ability, reduce the investment cost of mobile network, an evaluation method of reference base station service range in assisted Beidou navigation mobile positioning was proposed in this paper. Beidou navigation system model was established by STK firstly, and actual application scenarios were simulated, and then the link data of observed the same satellite by reference base station and UE at the same time was calculated respectively. Finally, the service range of reference base station was analyzed through the time of observation the same satellites. The simulation results showed that the service range of reference base station had a strong influence for the visible time of observed the same satellite by base station and UE. The assisted performance of Beidou would be seriously affected when the service range of reference base station was more than 300km. The results could provide a priori information for assisted Beidou mobile positioning business development.关键词：assisted;navigation;base stations;positioning;range
- 1973
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发布时间：2023-11-14 - 摘要：Abstract:Interference alignment (IA) in the multi-user MIMO interference channel with constant channel coefficients was considered. An iterative algorithm for finding the interference alignment solutions was proposed for the case where all interference alignment multiplexing gains are one. Traditional IA algorithm which minimizes the interference leakage (MIL) was not sum rate optimal with finite SNR, so in this paper perfect alignment constraint was relaxed in order to obtain better sum rate performance. The problem was first converted to a convex quadratic program problem based on the small step size assumption then all the precoding and decoding matrices were updated iteratively. Simulation results showed that the proposed algorithm achieves better sum rate performance compared with MIL algorithm at lower SNR, and almost the same at higher SNR.关键词：interference alignment;quadratic programming;interference channel;MIMO
- 1763
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发布时间：2023-11-14 - 摘要：Abstract: The past through the picture collection of buildings in plane texture construction method in the scene, and most of them are semi-automatic completed. According to this problem, the authors put forward a kind of solution method--By correcting the input image, fusion perspective texture images, a new method to eliminate the perspective distortion, texture image correction was proposed, through compensation of illuminant color estimation texture color. By the simulation experiment, The results show that the method avoids 3D measurement process, can solve the shooting process related issues such as uniform source of light, high light and shade lamp.关键词：Image correction;Building Reconstruction;Texture;mapping method
- 1956
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发布时间：2023-11-14 - 摘要：Abstract: In order to reduce the effect of the dynamic weather on the performance of outdoor vision system in videos such as rain and snow, a novel algorithm of image restoration for rain and snow was proposed. Based on the properties of RGB, the proposed algorithm worked only on main characteristics by projection high dimensional data to low dimensional space. Rain and snow were identified accurately. Also, fewer frames of videos and non transformation from one color space to another was simple to use. The effectiveness of our algorithms was demonstrated by six classical scenes. Experimental results showed that it could effectively discriminate the rain pixels and non-rain pixels.
- 1837
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发布时间：2023-11-14 - 摘要：Abstract:There are structural textures in the intra and inter residual blocks in video coding. There is also such a causal relationship between the texture characteristic and orthogonal transforms: the energy concentration effect is poor when the textures are strong, and conversely the opposite. Therefore, an adaptive transform skip mode is proposed based on the horizontal and vertical texture characteristic of the residual blocks in this paper. Firstly, the sum of the absolutes values of horizontal and vertical gradients are counted by computing the horizontal and vertical gradients of the prediction residual blocks based on the texture characteristic of the prediction residual blocks. The experimental horizontal and vertical gradient thresholds, which decide whether horizontal or vertical transform should be skipped to achieve better coding gains, are designed based on lots of experiments. Then, an adaptive scan mode is presented based on the transform skip mode. The final simulation results show that, compared with the recent HEVC conference software HM4.0, our proposed algorithm achieves 0.82%-8.92% more Bitrates saving and a little PSNR enhancement with some running time increment.关键词：HEVC;video coding;transform skip mode
- 1918
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发布时间：2023-11-14 - 摘要：Abstract:For the purpose of improving the anti-tracing performance of traditional Trojan communication model, we propose a new Trojan communication model which is consisted of Internet Relay Chat system and Webmail system. Internet Relay Chat system was applied for transferring command and Webmail system was used as a transit point. Due to the data forwarding of IRC servers and Webmail servers, tracers cannot build a direct route between Trojan user and target so that this model has a better anti-tracing performance. The measuring data of NS2 proves the good real time control performance of this model.
- 1818
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发布时间：2023-11-14 - 摘要：Abstract: Considering that when choosing cluster heads, the LEACH protocol does not take the nodes’ trust values and remaining energy into account, an improved method for choosing cluster heads was proposed in this paper. In transmitting stage, nodes’ trust values were computed according to their behaviors. In the next round, cluster heads were selected according to the nodes’ trust values. Afterward, the network’s life was prolonged and its safety was strengthened. Since the remaining energy was also considered when computing the nodes’ trust values, it did not have to be considered additionally. Experiments showed that the improved algorithm not only survived longer than LEACH, but also safer than LEACH protocol. than LEACH, but safer than LEACH protocol.
- 1659
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发布时间：2023-11-14 - 摘要：Abstract:A complete set of efficient and robust vehicle detection and tracking algorithms for high definition video was proposed based on the deep analysis of the complex urban traffic intersections. The realized intelligent surveillance system achieved integrated traffic surveillance, including traffic flow acquisition, vehicle violation recording and license plate recognition. The efficient two-step vehicle detection method was proposed, which firstly uses the robust inter-frame edge map difference for motion detection, then recognizes passing vehicles by the prominent properties of both the projection of license plate texture and the color of taillights. Vehicle tracking was achieved during a long spatial span by pyramidal Lucas-Kanade method based on large scale FAST corners as robust feature points during daytime and by taillight areas tracking with Kalman filters at night. The system provided promising performance in practice with 96.5% traffic flow accuracy and 87.6% effective ratio of traffic violation recording.关键词：vehicle detection;vehicle tracking;traffic violation;ITS
- 1529
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发布时间：2023-11-14 - 摘要：Abstract:In this paper, the engineering approximate methods of maximum torque per ample control (MTPAC) in a kind of interior permanent magnet synchronous motor (IPMSM) with high saliency were studied to improve the real time performance and control precision.According to the mathematical model of IPMSM in d-q axises, the distribution of d/q axis current under MTPAC was derived via extremum principle. For the correspondence between the d /q axis components of stator current and the eletromagnetic torque,a new polynomial fitting arithmetic that could divide curves automatically was proposed. Several quadratic curves were connected to approximate the whole relation curves under MTPAC. Less amount of calculation and higher accuracy were leaded to by the arithmetic than that of using single high order polynomial.Both the flowchart and the simulation results in Matlab were given.The results showed that this method was simple and feasible. In some degree,it had an instructive and directive significance to actual object practice.
- 1447
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发布时间：2023-11-14 - 摘要：Abstract:A numerical model of steady partial EHL lubrication was established under the asperity contact condition based on two dimensional rolling contact theory and partial elasto hydrodynamic lubrication theory. The adhesion property of wheel/rail under oil condition was investigated in detail using the numerical model and multigrid method. The distribution of contact pressure of wheel/rail was analyzed using the numerical model. Furthermore, the effects of rolling speed, load and surface roughness on the adhesion property of wheel/rail were investigated in detail. The results indicated that the width of contact area of wheel/rail under oil condition is lager than that under dry condition (about 1.5 times). The adhesion coefficient of wheel/rail under oil condition is smaller than that under dry condition. The adhesion coefficient decreased as the rolling speed increasing. With the increases of contact pressure, the adhesion coefficient decreased. When the surface roughness of wheel/rail was increasing, the adhesion coefficient of wheel/rail would increase obviously.关键词：Wheel/rail;Partial elasto-hydrodynamic lubrication;Multigrid method;Adhesion coefficient
- 1521
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发布时间：2023-11-14
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