最新刊期
卷 49 ， 期 Z2 ， 2017
- 摘要：Abstract:In order to solving the problem of low intelligence of arrival flights scheduling, arrival flights scheduling reinforcement learning model was proposed. First of all, the states, actions, agent, environment, rewards, constraint and Q learning of the model were defined. The state of arrival flights scheduling reinforcement learning was the arrival time of each arrival flight. The action of the model was the adjustment of the arrival time. The arrival time was adjusted by agent, the environment responded to the action, then a new arrival time and reward value were passed to the agent. The delay times, delay cost and impact on subsequent flights were chosen as the rewards. At the same time, the model considered the flight can not advance landing, the distributed arrival time was not earlier than the schedule arrival time and the arrival flow of the airport can not exceed the arrival capacity of the airport. The model was validated using of Shuangliu airport real flight data. First come first service model and reinforcement learning model were compared and analyzed from sequence, delay time, delay cost, delay cost of subsequent flights and rewards. The rewards value of first come first service model was 3164. The rewards value of reinforcement learning model was 2880. Reinforcement learning model was superior to first come first service model. The evaluation index, weight, constraint can be adjusted according to air traffic control actual working conditions. The model provided decision-making for air traffic controller.关键词：agent;air traffic;air traffic control;machine learning;reinforcement learning
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发布时间：2023-11-14 - 摘要：Abstract:The left abutment slope of Changheba Hydropower Station is high and steep of strong unloading effect in the developmental large fracture rock mass，which results in the complexity of rock mass structure and the diversity of deformation and failure mode of the slope. Therefore，it is indispensable for the review of slope stability to analyze the deformation and failure mechanism of slope. Based on the engineering geological survey，structural features of rock mass and monitoring data，statistics and partition of structural plane have been completed；the main reasons of the cracking are deduced；the deformation and failure modes are summarized. The fault fz-15 and its footwall rock produce compression deformation because of blasting excavation in the lower part of slope，and subsidence of its hanging wall rock causes the deformation of the slope. Immediately following，the shear deformation has happened along the joint set J6，then the upper rock mass has been dragged along joint set J3. And the slope tends to overturn along the joint set J2. Thus all directions of cracks are generated. The deformation and failure modes of the slope are sliding-tension and overturning-tension. After targeted support measures，the cracking have been controlled successfully and the slope is basically safe.关键词：high rock slope;deformation and failure mode;crack;structural plane statistics;Changheba Hydropower Station
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发布时间：2023-11-14 - 摘要：Abstract:Hydraulic vibrations generally exist in large units of hydropower stations. How to predict the hydraulic vibration before a hydropower station goes into operation is a significant research subject. Establishing a fluid-solid coupling mathematical model is an important step. This work focuses on interpolation methods used for fluid-solid coupling problems of hydropower stations. Advantages and disadvantages of typical interpolation methods in the world were discussed. The C2 compactly supported radial basis function is widely used in aeronautics, geomorphy, and medicine in recent years. The function was improved and optimized to develop a data transfer model for fluid-structure coupling interface. Turbine unsteady fluid grid and structural dynamics calculation grid were built. And a vibration analysis of hydropower plant was conducted. When the number of fluid mesh was much larger than the number of structural mesh, local interpolations were available to save time cost in construction project with large amount of grids. Errors were further reduced by improving C2 compactly supported radial basis function which was better for data transferring in large and complex coupling interface. Blade passing frequency was the main frequency of fluid in Hydraulic turbine runner. Pressure fluctuations caused by static and dynamic disturbance had significant impact on structural vibrations in hydropower station plant.关键词：Hydropower station plant;Fluid-structure interaction;Flow-induced vibration;Coupling interface;Data transfer;Radial basis function
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发布时间：2023-11-14 - 摘要：Abstract:Abstract: Accurate assessment of the temporal and spatial variation characteristics of the reference crop evapotranspiration in the main grain producing areas is of great significance to the optimal irrigation scheduling,irrigation system optimization,efficient use of farmland water and improvement of grain water productivity.Based on the daily meteorological data from 258 meteorological stations in main grain-production region,this paper calculated the Reference crop evapotranspiration from 1961 to 2013 by adopting Penman-Monteith formula,and analyzed the space-time variation during the 53 years by Sen’s+Mann-Kendall,Cumulative anomaly method and meteorological tendency rate.The results showed that:during the 53 years ET0 in main grain-production regions,Temperate humid and semi-humid area (I),Temperate arid and semi-arid area (II),Subtropical humid area (III) and Warm temperate semi-humid climate zone (IV) respectively were 901.90mm,741.89mm,1077.93mm,940.17mm (II>III>the whole region>IV>I);ET0 of the main crop growing season accounted for 87.58%,90.05%,85.11%,83.39% of the whole year,in the region and the various divisions;Except for IV(the tendency rate Y is 0.002mm/a ) ET0 in the whole region and I-III regions presented the decreasing trend during the 53years,the number of stations in downward was 171 accounting for 61.0％,the region slope decreased significantly and the trend variation was -0.288*mm/a（P<0.05）;The whole area and each district ET0 showed an increasing trend in 90s, the βwhole=4.993,Zwhole=1.978* (P<0.05) ,the trend of increase is significant,other decadal trend decreases; ET0 high value areas mainly concentrated in the northwest of Sichuan and Inner Mongolia,low value areas mainly concentrated in the Sichuan basin and the eastern part of the northeast plain to the north part of the region ;ET0 showed degression from northwest to southeast with apparent regional difference,the stations showed the high value,med-high value,median and low value respectively accounted for 3.5%,12.4%,58.5%,25.6% of the whole stations; During the recent 53 years,the variation in trend of ET0 was greater within the year,ET0 showed an increasing trend from north to south in spring, but it was opposite in summer, then in autumn,ET0 in the major grain producing areas showed the tendency of low in central and high in north and south,compared with the autumn,ET0 had significant decline in winner, and it presented an overall downward trend by “North-South,West-East”,on main crops growing season,the ET0 decreased in the North China plain(declined significantly) and the central Northeast plain, and it had an increasing trend around the North plain and the lower reaches of Yangtze River region.
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发布时间：2023-11-14 - 摘要：Abstract:The fishway entrance layout mode directly influences the hydraulic characteristics of fish luring flow. Whether the fish luring flow can be recognized by fish and suitable for migration determines the effect of fish luring, which is the key to the success of fishway project.This paper put forward two kinds of fishway entrance layout modes arranged on the pier and the fish luring channel respectively. To illustrate the influence of different layout modes on hydraulic characteristics of fish luring flow, this paper, have conducted three-dimensional numerical simulation on the two kinds of layout modes by using standard k-ε turbulence model and VOF model, then verified the rationality of simulation by physical model test results. Through comparing the flow pattern, velocity, the width of the suitable velocity and turbulent kinetic energy under the two kinds of layout modes, the results showed that the velocity of the fish luring flow under the layout mode arranged on the fish luring channel is smaller and the maximum velocity near the downstream shoreside decreases 1.0 m/s. The width of the suitable velocity（0.70 m/s~1.41 m/s）is wider and maximum width broadens 3.0 m. The kinetic energy is smaller and maximum kinetic energy near the fishway entrance decreases 0.60 m2/s2. Therefore the fish luring flow under the layout mode arranged on the fish luring channel is more suitable for fish luring and can guide the fish to migrate and find the fishway entrance more effectively. This layout mode provided a reference for fishway entrance layout design and study.关键词：fishway entrance;fish luring flow;hydraulic characteristics;k-ε turbulence model;VOF
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发布时间：2023-11-14 - 摘要：Abstract:Composite porous media embedded with impermeable spheres are widely used in the field of groundwater seepage, water flows through impermeable spheres in porous media due to the influence of impermeable spheres, and the closer the sphere is, the more obvious the phenomenon is. In order to get the seepage field and equivalent permeability coefficient, nonlinear Darcy Brinkman-extended equation was applied in spherical coordinates. With no slippage on sphere and the unidirectional uniformed flow at infinity as the boundary conditions, analytical solution of seepage velocity and pressure around the sphere was obtained .By analyzing the expression of the analytical solution, the results showed the velocity and pressure of the seepage field are related to the permeability of the porous media and the dynamic viscosity coefficient of the groundwater. On this basis, the Darcy averaged flow was obtained via integral of velocity to calculate the equation of equivalent permeability coefficient, the theory proves that the relative size of the sphere and the porous medium was the most important factor to affect the permeability coefficient of the composite. Finally, a certain graded sand was used as a porous medium, three kinds of organic glass spheres with diameters of 4cm, 6cm and 8cm were used as impervious spheres, the seepage test was carried out by self-made test equipment. In the experiment, the degree of compaction of the porous media was controlled to keep its permeability coefficient almost unchanged, and the seepage experiment was carried out by changing the impervious sphere filled in the porous medium. Three groups of experiments were performed on each impervious sphere, and the mean value was taken as the test result. The equivalent permeability coefficient deviations between test results and theoretical calculation were small, correctness of the calculation of porous medium seepage field embedded with impermeable sphere was verified.关键词：porous medium seepage;flow around sphere;Brinkman-extended Darcy equations;equivalent permeability coefficient
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发布时间：2023-11-14 - 摘要：Abstract:In order to investigate the spatiotemporal characteristics of soil failures on slope, artificial rainfall experiment was conducted. The movements of fine grains, slope failure sequences and pore-water pressure changes were observed; the samples of collapse mass, seepage water and soils after migration were obtained, grain-size analysis was conducted by sieving method and laser granular analyzer. The grain size distribution (GSD) parameters were used to compare the grain composition before and after the experiments, and the relationship between GSD parameters and soil strength was analyszed. The results show that: Fine grains migration leads to the soil fabric change, and the aggregation of fine grains causes increase of pore water pressure. Soil failures occur more frequently in the region of high hydraulic gradient. The observed irregular failure sequence can be ascribed to the spatial heterogeneity of grain composition and the fine grain migration. It is found that the shear strength and the internal friction angle decrease with the increase of fine content, and the GSD parameters are randomly distributed in the soil body, which leads to the random distribution of the soil strength, and finally to the random slope failures.关键词：laboratory tests;fine grain migration;scaling distribution;slope collapse;stochastic distribution
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发布时间：2023-11-14 - 摘要：Abstract:In order to study the deep anti-sliding stability of gravity dam foundation with different inclined structural planes, first, the three-dimensional (3D) geo-mechanical model test was used in C # dam section with double inclined structural planes of a water conservancy project, and a failure test was carried out based on overloading method. Through the test the failure mechanism of the gravity dam foundation was obtained and the overload safety factor K_p was found as 3.0. Then, the finite element method was used to analyze and calculate the sliding stability of the natural dam foundation with different inclined angles and the structural planes, Calculations proves that the overload safety factor with single inclined structural planes in gravity dam foundation K_c was equal to 2.6 and the overload safety factor with double inclined structural planes in gravity dam foundation K_c was equal to 2.4. The results indicate that the gravity dam failure process of modal test and finite element calculation were extremely similar for the gravity dam foundation with double inclined structural planes, Besides the overload safety factor obtained by the model test is slightly larger, The unstable sliding mode and failure mechanism of gravity dam foundations with different inclined structural planes are different. In this study, two different methods are used to compare and verify each other, and the failure mechanism of deep anti-sliding stability of gravity dam foundation with different inclined structural planes was revealed.关键词：gravity dam foundation;different inclined structural planes;deep anti-sliding stability;geomechanical model test;finite element calculation
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发布时间：2023-11-14 - 摘要：Abstract:When high dams discharge high velocity flows, large amount of air was taken into the water downstream of the dams, and the intense aeration between water and air leads to the generation of total dissolved gas (TDG) supersaturation. It gives threatens to the fishes’ survival especially those valuable and rare fishes. Experiments were conducted to measure the acute and chronic lethality on Leptobotia Elongata to TDG supersaturation. The fishes were placed in distinct tanks with different concentration of TDG-supersaturated water. The result shows that the median lethal times (LT50) of the Leptobotia Elongata were 152.81h, 64.02h, 14.89h when TDG supersaturation levels were 120%, 130% and 140% respectively. Throughout the trail, no fish died when exposed to 110% TDG. Furthermore, surviving fishes which had been pre-exposed to 110% and 120% TDG for 96h were sustaining re-exposed to two TDG supersaturation levels (130% and 140%). The resulting median lethal times were 8.72h and 7.14h which are 41.4% and 52.05% shorter than the former 140% level. And the median lethal times were 47.77h and 15.52h which were 25.56% and 75.81% shorter than the former 130% level as well. It appeals that the low TDG supersaturation level (110%) still has chronic lethality on Leptobotia Elongata.关键词：TDG supersaturation;Leptobotia Elongata;tolerance;Re-exposed;Chronic lethality
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发布时间：2023-11-14 - 摘要：Abstract:The drawback of Shields diagram is that the unknown variables appear in both ordinate and bscissa parameters. For the convenience of practical use, Vanoni build auxiliary lines using a third parameter X, the use of this auxiliary lines enables to determine its intersection with the Shields diagram and its corresponding values of shear stress. To build the auxiliary line, it is necessary to drawθ-X curve, firstly. Reanalysis the parameter X, it is found that X is a function of dimensionless diameter d*(X=0.316d*1.5). So θ-X relationship can be deduced with Yalin-Silva θ-d* equation. Using the Yalin-Silva θ-d* equation and experimental incipient data, auxiliary lines are developed in this note for finding the critical shear velocity. Then, the auxiliary lines equation is gotten, the slope of auxiliary lines is verified mathematically, also. Finally, a new set of auxiliary lines are built in the rang of 0.01≤Re*≤1000, unlike the original Vanoni auxiliary lines, they lie on the top of θ=0.1 line in Re*<1 region.关键词：Shields diagram;logarithmic coordinates;auxiliary line;sediment incipient motion
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发布时间：2023-11-14 - 摘要：Abstract:This paper based on the Shuangsheng section of Shiting River, a typical mountain river in Sichuan. The study mainly focused on those river construction distributed around this section.(This section contains the Culvert of the People’s Canal, the Shiting River Bridges of Chengdu-Lanzhou Railway and Chengdu-Mianyang Double-Track Highway,etc.) The bridge pile foundation in Shuangsheng section of Shiting River has been exposed up to 10m due to the flood during 2009-2013; the culvert increased the incision degree of riverbed and it declined 20.29m. Based on the HEC-RAS sediment calculation module, this paper studied changes of local base level of erosion on the riverbed and the impacts to evolution of riverbed under the condition of sediment refining and the clear water scouring. The numerical simulation showed that the changed local base level of erosion caused headward erosion and changed the gradient of a part of riverbed. The hardening projects of culvert intensified the fluvial process, and the junction with riverbed caused scour pit, in order to balance the erosion it is suggested to lower the evolution of the culvert. And the hardening project of bridges both intensified erosion and deposition, and accumulated the deposition between two bridges. According to the clear water scouring, the results were adequate as a prediction of fluvial process effected by river construction projects in mountain rivers. This project provided a reference for comprehensive development for river and the management. This analysis can be further develop to the study of the impacts of the destruction of armor layer under human factors such as sand mining, and it can be the reference for the design and protection of river construction. To reference the channel management after earthquake the study can combine the fluvial process both on cross section and profile to analysis the change of hydrodynamic and sediment after earthquake.
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发布时间：2023-11-14 - 摘要：Abstract:Significant channel degradation has occurred along the Upper Jingjiang Reach (UJR) because of the operation of the Three Gorges Project (TGP), leading to the corresponding adjustments in low-water channel geometry. The section-scale low-water channel dimensions at each section in the UJR were first calculated by a one-dimensional hydrodynamic model. Due to the remarkable longitudinal variability in cross-sectional geometry, a reach-averaged method is adopted to calculate the reach-scale low-water channel dimensions in this reach annually from 2002 to 2015. Calculated results indicate that (i) the reach-scale low-water width changed slightly owing to the restriction of various river regulation engineering, and the corresponding depth and cross-sectional area respectively increased by 0.68 m and 870 m2, which led to a continuous decrease in the width-depth ratio from 5.73 in 2002 to 5.17 in 2015. Therefore, the low-water channel gradually developed into a narrow and deep shape in the UJR, with the low-water navigation condition being generally improved; (ii) however, the width-depth ratio at low water significantly increased in some subreaches such as the site of Huojianzhou, as well as the Shashi and Gongan bends. It is further explained that the central-bar and convex point-bar in these regions underwent dramatic degradation, which finally contributed to deteriorating the navigation condition. In addition, empirical relationships were developed between the reach-scale low-water channel dimensions and the previous flow and sediment regime. The results show that (i) the degree of correlation between the reach-scale low-water width and the previous flow and sediment regime was only 0.37, so the developed relationship cannot be applied to predict the variation in the low-water width; (ii) the reach-scale low-water depth, cross-sectional area and width-depth ratio correlated closely with the magnitude of the previous flow and sediment regime, with high correlation degrees of 0.92, 0.95 and 0.85 being obtained respectively. Therefore, these low-water channel dimensions can respond well to the altered flow and sediment regime caused by the TGP operation.关键词：low-water channel geometry;flow and sediment regime;channel adjustments;navigation condition;Upper Jingjiang Reach;Three Gorges Project
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发布时间：2023-11-14 - 摘要：Abstract:Human activities are closely linked to the riverbed evolution and the hydraulic geometry of river, which make the mountains river a series of change in morphology and sediment movement. In recent years, with the rapid increase in the demand for building sand, people mined river sand on a large scale, which changed the original river bed boundary condition of rivers and had considerable impact on riverbed evolution. Studying the influence of sand mining on the riverbed evolution of rivers has important academic and practical significance. Based on the HEC-RAS sediment calculation module, in combination with the practical field investigation, the numerical simulation had several kinds of sandpits in order to study the influence of different longitudinal profile dimensions of sandpit on the riverbed evolution of rivers. According to the data and the practical field investigation, firstly the experiment protocoled HEC-RAS section distribution of numerical model and boundary condition. And then on the condition that the volume and width of sandpit was almost same, five kinds of sandpits with different depth-length ratio was set up. After simulation by HEC-RAS sediment calculation module, the data of the reach longitudinal profile and sediment erosion or deposition of every section were counted and analyzed. The results indicated that erosion of riverbed were promoted by artificial sand mining and negative related to depth-length ratio of sandpit. In addition, with the increase of depth-length ratio, that erosion of upstream declined, while erosion of downstream was different which declined at first and then grown. What’s more, Sandpit would change the channel local slope and the upstream local slope increased, while the downstream local slope decreased. The conclusions can provide certain reference to the protection and design of across river buildings and exploiting plan.关键词：sandpit;depth-length ratio;fluvial processes;numerical simulation
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发布时间：2023-11-14 - 摘要：Abstract:With the continuous development of the water treatment, many new request was put forward on the AOPs, more and more catalysts have been developed and used in the field of AOPs. In the experiment, catalytic performance of NiOx and the advantages of NiOx/PMS/US system on dye wastewater were investigated. NiOx catalyst was prepared by sol-gel method and the acid orange 7 (AO7) act as degradation substrate. The results indicated that compared to NiOx/H2O2/US and NiOx/PDS/US system, the effect of NiOx/PMS/US system was much better. The effect of calcination temperature, [oxidants]: [oxidation substrate], catalyst dosage, power of US were also investigated, and the results show that the degradation rate decreased while calcination temperature increased. In addition, the [oxidants]: [oxidation substrate] raised from 20:1 to 70:1, the degradation rate increased from 77% to 95%. However, while further increase of [oxidants]: [oxidation substrate] may suppress the degradation efficiency. With the catalyst dosage increase from 120mg/L to 280mg/L, the degradation speed increased, however, no obvious change in degradation rate occurred after further increases of catalyst dosage. Higher amount of US power can accelerate the reaction, however, it only showed a slight increase with further increases of US power from 400W to 500W. The reuse of the catalyst and degrade of methyl orange (HIn) and reactive brilliant blue (KN-R) proved the stability and universality of NiOx/PMS/US system. The XRD patterns of NiOx show that the catalyst at the best calcination temperature is mainly composed of NiO, Ni and amorphous carbon. Because of its excellent catalytic activity, stability and universality, NiOx can play an important role in AOPs, thus, NiOx is an efficient catalyst. Nowadays, the main factor which restricting the economic benefits of NiOx is the high cost of preparation and difficulty in mass production. Therefore the foremost research aim is to reduce the cost of preparation of the catalyst. When these defects are resolved, this catalyst will have a bright future in AOPs field.关键词：chemical reaction engineering,AOPs, NiOx, PMS, dye wastewater
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发布时间：2023-11-14 - 摘要：Abstract:At present, when processing the waste glass, people usually adopted the method of the landfill in our country, which causes environmental pollution and resource waste. In order to achieve the recycling of waste glass, the natural coarse aggregate, fine aggregate in concrete and some gel material made by cement powder waste was replace by broken waste glass to be made into standard specimens. Then the relationship between waste glass content and waste glass concrete performance and the compressive strength according to the standard test method under the condition of testing mechanics and performance of glass concrete specimen with different dosage of glass particles is discussed. At the same time, the effects of age on the strength of glass concrete are tested. According to the study, it is found that the incorporation of glass aggregates in concrete leads to a loss of mechanical performance, though this is not significant in optimal waste glass replacement of the natural aggregates. And when regarding the mechanical strength and waste glass substitution rate as the index, the optimal waste glass replacement ratio of recycled concrete which are as follows: 25% coarse aggregate of waste glass, 25% fine aggregate of waste glass, 0% glass powder. Under the condition of optimum replacement rate, the performance of waste glass concrete is better than the reference concrete. When using 75 um glass particle to replace concrete cement, the glass concrete properties is reduced. However, when the replacement amount is less than 10%, less influence would be exerted on the strength of the specimens. The experimental result shows that it is feasible to replace natural aggregate of the concrete with the waste glass particles in a certain proportion and it provides parameters for the glass concrete application in engineering.关键词：waste reinforced glass concrete;compressive strength;mechanical properties;the optimal replacement ratio
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发布时间：2023-11-14 - 摘要：Abstract:Abstract: The shear mechanical properties of steel-glass end face joints bonded with adhesives were tested with three adhesives and two kinds of testing methods - double face tensile-shear test (DFTST) and single face tensile-shear test (SFTST). The DFTST was used to test the shear mechanical properties of 3M DP190 and silicone 999, while the SFTST was used to test the shear mechanical properties of silicone 992 with three different bonding lengths. The results show that SFTST is more convenient than DFTST; silicone structure adhesive has lower shear strength and better deformation ability; putting the glass vertically during the bonding operations is an effective way to ensure the quality of the adhesive layer; with the increase of bonding length, the displacement at failure doesn’t have obvious change, the shear stiffness of the bonding joints increases in direct ratio. The research provides appropriate test methods and referable data for the engineering application.
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发布时间：2023-11-14 - 摘要：Abstract:Backfill mining was an effective way of realizing green mining, and the key part of its application was to do some research into the filling materials. The high-water material was a new kind of filling material, the physical and mechanical properties of high-water material that used for goaf filling directly affect the filling stability, solid particles and water are the main components of high-water material, the relative content of which directly affect its physical and mechanical properties. Based on a series of macroscopic and microscopic tests, the basic physical properties and uniaxial compressive strength characteristics of high-water material with different water cement ratio were studied. The results indicated that 1) Microstructure of high-water material stone exhibits a network structure and is very porous, so it can absorb quantities of water which was greater than its weight. The greater the water cement ratio is, the sparser the fissures in reticular formation will be and thus the larger the reticular formation will be. The phenomenon of dehydration became much more evident when the high-water material’s water cement ratio got larger and when it was under the action of uniaxial compression. 2) The stress-strain curve of high-water material is similar to that of rock material, however, the high-water material exhibits high plasticity and can maintain better integrity after reaching peak strength. 3) Under uniaxial compression, the high-water material often show "X" type shear failure when the water cement is relatively high; but it often shows splitting failure when the water cement is relatively low. The uniaxial peak strength and residual strength of high-water material reduced with the increase of its water cement ratio. With the decrease of water cement ratio, the stress-strain curve at the peak strength became much steeper and the strength after the peak stage reduced much faster while its residual strength remained a higher level. 4) The high-water material displays excellent plastic properties and high residual strength, which is suitable for filling material.
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发布时间：2023-11-14 - 摘要：Abstract:High-water-content material widely serves as the filling materials, its size and shape has a distinct impact on the mechanical properties. In order to studying the mechanical properties of different shape and size,using the analytic equipment of ETM mechanics system in SCU, testing the nature of the destruction progress, compressive strength and deformation characteristic in different size and shape of high-water-content material doped the fly ash. The results indicated that high-water-content material is elastic-plastic material, the deformation and failure progress can be divided into 4 stages, respectively, plastic stage, shaping stage, yield stage and destruction stage; Size only affects the stress - strain curve of the peak strength, however, the shape has greater impact to the peak strength and shape. In the certain ranges, with the increase in size of the material, elastic modulus, deformation modulus gradually decreases within a certain range, the compressive strength of cylinder specimen is greater than cube specimen. Under the same conditions, the elastic modulus and compressive strength of cylindrical specimens is greater than cubic specimens, but deformation modulus is more smaller.关键词：high-water-content material;mechanical properties;size effect;shape effect
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发布时间：2023-11-14 - 摘要：Abstract:Abstract: In order to study the scouring effect on particles in a loose granular slope with surface runoff，an analytical model was set up on the basis of the characteristics of slope runoff and seepage. A generalized equation known as the Brinkman-extended Darcy equation is solved inside the seepage zone, along with the incompressible Navier–Stokes equation in the upper runoff zone. We also use the continuity equation for both regions and a Neal–Nader boundary condition on the interface of the two regions. Combining Navier–Stokes equation and Brinkman-extended Darcy equation with the continuity equation can derive the flow velocity distributions of fluid in both regions, respectively. And the flow velocity is increase by the growing effecting factors. According to the flow velocity expressions, it is noted that the velocity mainly depends on slope gradient, runoff depth, porosity and permeability of the slope earth. In order to investigate the starting mechanism of particles on slope under the condition of runoff, Newton’s law of friction is introduced, and the shear stress at the interface of the two regions is obtained. The two cases of particle sliding and rolling are analyzed respectively, and the corresponding instability criterion of particle in sliding and rolling are presented in the two motion modes. Based on the analysis of the two criterions, it can be concluded that: (1) For the sliding case, the anti-sliding stability coefficient is mainly affected by the slope gradient, friction angle, particle radius, runoff depth and the porosity and permeability of the slope earth, and it increases with the rising of the internal friction angle, particle radius, porosity and permeability of the slope earth, and decreases with the drop of the slope gradient and runoff depth; (2) Whether the particle rolls or not depends mainly on the slope gradient, runoff depth, particle radius, and the porosity and permeability of the slope earth, and the larger the value, the easier the instability of the particles.关键词：Keywords: loose granular slope;coupling of runoff and seepage;shear stress;scouring mechanism;instability criterion
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发布时间：2023-11-14 - 摘要：Abstract:In order to understand salt rock damage recovery characteristics and the connection of damage and strength under the effect of confining pressure. Different test has been designed for salt rock with different confining pressure and different holding time of confining pressure. The results showed that at early loading, the salt rock elastic modulus increases gradually along with the increase of the pressure holding time, and with the increase of pressure holding time, the corresponding axial strain and lateral strain of salt rock peak stress will increase gradually. There is a negative correlation between salt rock damage and strength .With the increasing of holding time of confining pressure the intensity of salt rock gradually increasing, and finally tends to maintain a relatively stable state. The damage recovery of salt rock can be divided into rapid damage recovery phase and slow damage recovery phase under the effect of confining pressure, and there is a distinct time node for different salt rock damage recovery phase. Within a certain range, with the increasing of the strength of confining pressure in the stage of holding confining pressure, the duration of salt rock rapid damage recovery phase is gradually reduced. The duration of salt rock rapid damage recovery phase can be shorten with the increasing of the strength of confining pressure in the stage of holding confining pressure. However, with the increasing the strength of confining pressure, new damage may be caused in the salt rock.关键词：salt rock;holding time of confining pressure;keeping strength of confining pressure;damage recovery
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发布时间：2023-11-14 - 摘要：Abstract:Dynamic finite-difference scheme was widely used in dynamics simulations. However, there are few reports about the effect of integral paths and element types on the calculation accuracy of such algorithm. For such problem, A finite-difference scheme based on Lagrangian solver was developed by using arbitrary elements. The wave propagation in a thin rod model was simulated using a dynamics code developed by JAVA, and a comparison of several types of integration paths was carried out. And the wave propagation in infinite medium was also simulated. From the point of energy error, the weakness of quadrilateral meshes results from Hourglass mode was revealed. The results showed that the computational domain must be completely covered by the control volume, and the triangular meshes are more applicable as compared to quadrilateral meshes because they can avoid the energy error induced by Hourglass mode.关键词：dynamic finite-difference scheme;different integration path;hourglass mode;energy error;calculation accuracy
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发布时间：2023-11-14 - 摘要：Abstract:To study the basic characteristics of the energy and the acoustic emission angle in the process of rock salt deformation , the uniaxial loading and unloading tests were carried out with pure salt rocks from Pingdingshan and Huaian by using MTS815 Flex Test GT and acoustic emission monitoring system. The research show that the elastic deformation stage is very short, the yielding process produced large plastic deformation, the stress did not decrease sharply after peak, and the hysteresis loop area between loading and unloading curve is always very small under uniaxial loading and unloading conditions. In the whole experiment, the proportion of elastic strain energy is very small; in the process of rock salt deformation and failure, the dissipation energy increases with the increase of the strain, the rate of rise is incremental, the rate of rise tends to be constant when the stress is close to the peak value, and the dissipation energy curve begin to present linear growth; the elastic strain energy increases before the peak of stress, the rate of rise is diminishing, it reaches the peak value at the peak of stress, and it is decreased after the peak of stress. The AE count rate and energy rate emerged in large quantities in the initial stage of the test, then it downward into the stable development period in the yield stage, until the peak of stress, it appear an inflection point accumulative count and cumulative energy curve, it appear the ladder shape development at a higher rate after the peak of stress. This paper has some practical guiding significance in the process of water soluble excavation and the gas recovery of salt rock gas storage.关键词：rock salt;hysteresis ring;energy dissipation;elastic strain energy;counts
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发布时间：2023-11-14 - 摘要：Abstract:The surrounding rock of surge-shaft in proposed Hydropower Station contains mainly quartz mica schist, After exploration and laboratory tests, It found that the rock belongs to soft rock ,which has obvious schistosity structure and typical transverse isotropic rheological characteristics. The rheological behavior of surrounding rock during construction and operation may significantly affect the stability of rock mass and the characteristics of lining structure due to the high level of regional crustal stress. In this paper, Through comprehensively reflecting regional geological structure, structure of the surge shaft and stress fields, A three dimensional numerical calculation model is established with considering the construction sequence and supporting lining measures, according to Viscoelastic plastic damage constitutive model of transversely isotropic rock mass based on laboratory test and field monitoring data, Study on the stability of surrounding rock and lining structure safety of the surge-shaft group during construction and operation by using FLAC3D. The results show: Under the influence of rheological effect of the surrounding rock in the process of construction excavation, Deformation of the surrounding rock increases with time, The effect of anchor support on the deformation of surrounding rock is obvious. After 500d excavation, the displacement of surrounding rock tends to converge; the surrounding rock is in a state of compression after excavation, The two times lining is conducive to the distribution of the stress field of surrounding rock. The value of the growth rate of surge shaft lining deformation gradually decreased with time during operation, The deformation of the 2 year is about 54% of the deformation of the long term (50 years). The stress level of surge shaft lining structure and surrounding rock tends to be stable after 1 years of operation. During operating period, The variation range of stress level of surrounding rock of surge-shaft is very small.关键词：mica-quartz schist;surge-shaft group;damage rheology;finite element;aging stability
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发布时间：2023-11-14 - 摘要：Abstract:In order to study creep characteristics of salt rock with impurities, the triaxial loading tests about two salt rock with different impurity content were carried out on large-scale programmable rheometer of Sichuan university, The results showed that the failure pattern and mechanical parameters of salt rock are different as the change of confining pressure or content of impurities, The destructional form of salt rock change from shear to drum type when the confining pressure increase. The steady-state creep rate of each sample grows exponentially with the deviatoric stress when confining pressure and impurity content is the same. As increase of confining pressure, the creep rate is depressed, but the long-term strength is increased when deviatoric stress and impurity content is the same. The steady-state creep rate of low-impurity(ω=2.1%) is higher than high-impurity(ω=46.8%) when deviatoric stress and confining pressure is the same. Volume strain experienced three period:pressure dense-quiet-dilatation, the volume strain of salt rock with high impurities inferior to the low impurity.A fractional unsteady creep damage model is established by introducting the relationship between insolubles impurity content and stress sensitivity constant to constitutive equation of creep.The reasonability of this model was proved by comparing the theory model with experimental data.关键词：triaxial;creep;impurities;salt rock;volume deformation;fractional order constitutive model
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发布时间：2023-11-14 - 摘要：Abstract:In view of the most existing user attribute prediction methods based on application that is less considered actual use time of application in the foreground, put forward average use time of application in the foreground, At the same time, the Co-training framework based on sparse autoencoder and neural network is adopted, make full use of a large number of unlabeled data, predict user attribute from application category and average time used of application in the foreground. When the experiment is carried out, first the network is initialized with unlabeled data, then the gradient descent algorithm based on accuracy is used to update the parameters. Experimental results show that the proposed algorithm improves the accuracy of user attributes prediction.关键词：User attribute;Co-training;Sparse autoencoder;Gradient Descent Algorithms
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发布时间：2023-11-14 - 摘要：Abstract:An on-orbit reusable refueling policy and its mission scheduling for multiple geosynchronous satellites through a space fuel station is presented. In order to establish the scheduling model for the on-orbit refueling of multiple GEO satellites through a space fuel station, the relationship between the velocity change and the maneuver time for orbital transferring of service spacecraft is first obtained based on the analysis of the problem of two impulses orbital maneuver. A multi-objective optimization model for mission scheduling of on-orbit refueling for multiple GEO satellites is developed to optimize both the job sequence and job time distribution of the refueling mission, and a specifically design genetic algorithm is employed to search the solutions to this multi-objective optimization problem. To verify the effectiveness of the proposed scheduling algorithm, a computer simulation that aims at scheduling a mission of on-orbit refueling for 20 GEO satellites is conducted.关键词：On-orbit refueling;Mission scheduling;Genetic algorithm;multi-objective optimization
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发布时间：2023-11-14 - 摘要：Abstract:In order to analyze the impact of social networks on the spread of public opinion, the multi-source network community structure characteristics and its propagation characteristics was studied. Furthermore, the overlapping community was discussed using COPRA algorithm and LFM algorithm in social network and the improved algorithm of LFM based on filtering node degree——NF-LFM algorithm was proposed. In this algorithm, the node whose node degree is less than a certain threshold in the friend relation network was filtered, and then the rest of the network was divided into community structure. The results showed that: 1) The social networks such as Renren, Qzone and Microblog have obvious characteristics of the community structure, of which Renren and Qzone is stronger than Microblog. 2) Without taking into account the user activity, the diffusion range of public opinion information in Renren is larger than the others. The proposed method can not only solve the resolution problem of the existing algorithm in the community division results effectively, but also make up for the shortcomings of the LFM algorithm, which is caught in an infinite iterative process and leads to high time complexity. It is also in line with expected results when is applied to the classical data set. The results of this paper can help researchers to understand the impact on public opinion spread in community. It also has important significance for the discovery of network group incidents and guidance of public sentiment.关键词：social network;community detection;overlapping community;NF-LFM algorithm;node degree
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发布时间：2023-11-14 - 摘要：Abstract:Abstract: In trusted computing, the binary attestation scheme has some shortcomings that it reveals the information about the configuration of a platform which may lead to privacy issues such as discrimination services, anonymity violations and targeted attacks, etc. A property remote attestation based on attribute-based signature is proposed. The attribute signature’ policy (attribute tree) is mapped to security property in remote attestation. As anonymity of ABS, the verifier can’t know the specific configuration and the signature reveals no more than the fact that prover with some set of attributes satisfying the predicate(security property) has attested to the message. Multi authorities manage the platform configurations and generate attribute signature together without using property certificates. We prove the security of our scheme under standard model, that the scheme satisfies the correctness, unforgeability and configuration privacy.关键词：trusted computing;remote attestation;property based attestation;attribute based signature
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发布时间：2023-11-14 - 摘要：Abstract:For the problem that convolutional kernels of typical convolutional neural network set by experience and being difficult for fixed network architecture to realize subsequent re-learning, a new Convoutional neural network (CNN) model was proposed based on Sparse Autoencoder(SAE) and typical CNN. By SAE pre-training convolution kernels and increasing a branch based on typical CNN, only branch weights of the model were updated while doing subsequent re-learning, and new features were added while memorizing existing characteristics. On dataset MNIST, recognition rate of 97.65% was achieved by updating weights for 10 times. Recognition rates of more than 93% were achieved on dataset HCL2000. The recognition rate of similar Chinese characters reached 80.36% using 50 samples for training, 250 for testing. Compared with typical CNN and traditional methods, the proposed method was more generalized. Experiments show that the proposed method can be effectively applied to image recognition applications such as handwritten characters.关键词：convolutional neural network;sparse autoencoder;unsupervised pre-training;subsequent re-learning;handwritten characters recognition
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发布时间：2023-11-14 - 摘要：Abstract:In the distributed application scenario, as the shortcoming of resources and communication bandwidth wasting caused by a large number of chaotic sequences, which constructed the measurement matrix, a algorithm of structuring circulating measurement matrix was put forward based on Chebyshev spread spectrum sequence, in which Chebyshev chaotic function was used to generate the sequence and the spread spectrum sequence got by the symbol function, generated the measurement matrix by circulating the spread spectrum sequence. At last, the sequence by circulating was proved obeying the Bernoulli distribution. Simulation results show that Compared with Chebyshev Bernoulli matrix, Bernoulli matrix , Gaussian matrix and Logistics chaotic matrix, under the same compression ratio, a new matrix on one-dimensional signal had the same recovery effect as other matrix, but had the better recovery effect on the 2d infrared image and nature image.关键词：Compressed sensing;chaotic sequence;distributed circulate;measurement matrix
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发布时间：2023-11-14 - 摘要：Abstract:The image haze removal algorithm based on dark channel prior is simple and effective. However, this algorithm has high time complexity for high resolution images, low brightness for the results of restoration, color distortions for the images with large high-light area. To solve these problems, a modified adaptive algorithm based on dark channel prior was proposed for single image haze removal in this paper. In the proposed novel algorithm, the adaptive guided image filtering algorithm was adopted to instead of soft matting for increasing the computing efficiency and obtaining the optimized radius of filtering window at the same time. Moreover, adaptive transmission and brightness adaption were also applied to overcome color distortion problems and enhance the performances of the original algorithm. Both synthetic hazy images and real scene images were used for the validation of the proposed algorithm. The absolute different values (a full-reference way) and CNC (Contrast-naturalness- colorfulness) system (a no-reference way) were respectively used to assess the haze removal results for the synthetic hazy images and real scene images. The statistical results indicated that the proposed algorithm was more effective than the original algorithm according to the quantitative criteria as well as the human visual perception when the images have the same resolution and size.关键词：Haze removal algorithm;dark channel prior;adaptive;clearness effect assessment
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- 425
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发布时间：2023-11-14 - 摘要：Abstract:A semi-supervised feature learning method based on deep stacking network (DSN) is proposed aiming at resolving the waste of unlabeled samples in supervised learning and the information loss caused by artificial feature extraction. The unsupervised feature learning process is completed by the parallel training of multiple restricted Boltzmann machines (RBMs) and the trained parameters are utilized to initialize the input weights of the deep stacking network. Then the batch-mode gradient descent algorithm is utilized for supervised fine-tuning. The proposed method is applied to classify the motor imagery EEG signals. Experimental results demonstrate that the proposed method can take full advantage of the implicit information in unlabeled samples and efficiently extract EEG features. The average recognition accuracy is superior to other algorithms like common spatial pattern (CSP) and deep belief network (DBN). The proposed method can be applied to improve the recognition accuracy of EEG signals in a BCI system.关键词：deep stacking network;semi-supervised learning;restricted Boltzmann machine;feature extraction;EEG signal recognition
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发布时间：2023-11-14 - 摘要：Abstract:Due to high hardness, great wear resistance and good corrosion resistance, WC-based coatings are widely used in industry to increase the wear resistance and corrosion resistance of components. As the development of industry, the properties of WC-based coatings are demanding higher and higher. In thermal spraying processes, Atmospheric plasma spraying (APS) has unique advantages due to large range of temperature and highest tens of thousands of temperature, which can melt refractory materials. The high-velocity-oxy-fuel (HVOF) is widely used in thermal spraying with its high velocity of flame and kinetic energy of powders. With the cooling by N2 during spraying, the coatings sprayed by HVOF show better property. This paper focused on the microstructure and properties of WC-10Co-4Cr, WC-17Co coatings sprayed by HVOF/APS on AISI 1045 steel. The hardness, metallographic structure, adhesion with substrates, decarburization during spraying of two coatings was investigated separately. The results showed that the powders of HVOF coatings melted incompletely and had high kinetic energy, resulting in more smooth coating. The adhesion with substrates of HVOF coatings was higher than APS coatings according to metallographic structure. Furthermore, porosity of all coatings sprayed by HVOF was much higher than APS sprayed coatings and the WC-17Co coating sprayed by HVOF had lowest porosity (0.65%). Besides, the hardness of coatings sprayed by HVOF was higher than APS sprayed coatings. Due to lowest binder content, the WC-10Co-4Cr sprayed by HVOF had highest hardness. From XRD, the coatings sprayed by HVOF had very slight decarburization with the existence of little W2C. However, the decarburization of APS sprayed coatings was more serious. There existed a large amount of W2C and little Co3W3C, Co6W6C (η phase) due to its higher temperature and lower velocity of flame during spraying. Accordingly, HVOF was more suitable to spray WC-10Co-4Cr, WC-17Co coatings.关键词：APS;HVOF;WC-10Co-4Cr;WC-17Co;microstructure
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发布时间：2023-11-14 - 摘要：Abstract:In order to solve the shortcomings such as high sintering temperature, long sintering time and severe grain growth in the preparation of W-Cu alloy by traditional sintering technologies, W-Cu alloy was rapidly sintered by spark plasma sintering (SPS) and large current resistance sintering under an electric field which promoted the sintering process. With the help of Archimedes drainage method, metallographic microscope and scanning electron microscope etc., the densification degree and microstructure of W-20wt%Cu alloy prepared by two kinds of electric field rapid sintering methods at different sintering temperature (800℃, 900℃, and 1000℃) were studied.Through the calculation of the electric field density in two sintering methods and the appearance of the copper pool in the microstructure, the results showed that: large current resistance sintering was more likely to have a field emission effect compared with SPS, this was favorable for the microstructure and densification of W-Cu alloy. Samples sintered under large current resistance?possessed higher relative density and more?homogeneous microstructure, in?comparison to?samples from?SPS. In spark plasma sintering, the relative density of sintered samples increased and the uniformity of microstructure improved with the sintering temperature increased from 800℃ to 900℃; while concentration distribution of holes and aggregation of particles could be seen in sample sintered at 1000℃. However, the relative density of sintered samples obtained under large current resistance sintering increased and the uniformity of microstructure improved with the sintering temperature raising.关键词：electric field;rapid sintering;W-Cu alloy
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发布时间：2023-11-14 - 摘要：Abstract:Abstract: Aiming at the dynamic and static performance and lightweight design requirements of the fast reactor loader arm, the safety of the original structure was verified by finite element analysis. Solid isotropic microstructures with penalization (SIMP) of artificial materials method was proposed.Introducing the normalization coefficient,the dynamic and static multi-objective topology optimization mathematical model was established to combine the multi-condition stiffness and the dynamic key low-order frequencies into minimun combined compliance index,and the global Pareto solution was obtained. The results showed that the dynamic performance of the redesigned arm based on the topology optimization results increased greatly with a decreasing about 10% of maximum Tresca stress under SSE condition and a decreasing about 21.5% of weight,well meeting the structure optimization goal of improving performances and reducing weight .
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发布时间：2023-11-14 - 摘要：Abstract:Fibre reinforced concrete possesses more excellent properties of cracking resistance, reinforcing strength and toughness than plain concrete, hence can fulfill more requirements in the modern concrete constructions. In the current paper, the twisted ultra-high molecular weight polyethylene (UHMWPE) fibre of high strength, high elastic modulus as well as low density was employed as the reinforcement, the quasi-static mechanical properties of a new type of fibre concrete (FRC) were experimentally investigated. The C70 high strength concretes with four different fiber volume fractions (FVF) were developed by improving the process of preparation, then the splitting tensile tests, cubic uniaxial compression tests as well as the prism axial compression tests of the FRC were conducted, respectively, to investigate the effect of the FVF on quasi-static strengths and deformation behaviors of the FRC. The comparisons between the mechanical properties of current studied UHMWPE FRC and concrete reinforced by general UHMWPE fibre without treatment as well as the Polypropylene fibre have been performed. The results show that the fibre dispersed more evenly using this improved mixing method which promoted the workability of FRC. The integrity of concrete was maintained and fall-out of fragments was avoided due to the added UHMWPE fibre. The splitting tensile strength, increasing from 47.2% to 78.6% with the fiber content from 0.3% to 1.0% compared with the plain concrete, was significantly improved by the twisted UHMWPE fibre. However, the compressive strength of the concrete was not significantly enhanced by the UHMWPE fibre, while the improvement of the residual compressive strength was remarkable. Both the peak compressive strain and Poisson’s ratio increased with the increase of the FVF, whereas the elastic modulus had an opposite variation trend. The compressive toughness index ηc15.5 of FRC was 1.40~2.53 times of that of the plain concrete. Twisted UHMWPE fibre has improved the splitting tensile strength of concrete more significantly than the other two types of fibres, and enhanced the uniaxial compressive strength to a certain degree.
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发布时间：2023-11-14 - 摘要：Abstract:The cationic surfactant of fatty alcohol-polyoxyethylene ether is a multi-functional surfactant, which played an important role in the industry of detergent, textile and so on. Fatty alcohol-polyoxyethylene ether chloride（AEO3-Cl）is the intermediate to synthesize the cationic surfactant of fatty alcohol-polyoxyethylene ether. The traditional halogenating reactions are always used the volatile organic solvents, which have great pressure to the environments. In addition, the drawbacks of those catalysts in halogenating reactions, such as, long reaction time and many by-products, are need to be solved. However, as the introduction of cleaner technologies has become a major concern throughout both industry and academia, the search for alternatives to the most damaging solvents and excellent catalysts has become a high priority. AEO3-Cl was synthesized via halogenation reaction of reactants fatty alcohol-polyoxyethylene ether (AEO3) and thionyl chloride (SOCl2) which was catalyzed by ionic liquid 1-octyl-3-methylimdazolium bromide ([OMIM]Br). The effects of reaction temperature, reaction time, amount of SOCl2 and the amount of [OMIM]Br on conversion rate of AEO3 were investigated. The structure of the synthesized product was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and H Nuclear Magnetic Resonance (1HNMR). The results showed that [OMIM]Br is an effective catalyst for the reaction in room temperature and the conversion rate of AEO3 is reaching over 99%, with the following optimum reaction conditions of AEO3:SOCl2:[OMIM]Br=1:1.3:1 (molar ratio), the reaction temperature 25 ℃ and reaction time 30 minutes. The product was separated from the reaction mixture by extraction using n-hexane followed by the evaporation of n-hexane. The catalysts can be re-used for six times without obvious decreases of conversion, which showed that the catalysts have good recycling performances. In addition, it was suggested that the C2-H atom in [OMIM]Br could form hydrogen-bond with oxygen atom in hydroxyl group of AEO3, which reduces the reaction barrier, therefore led to high reaction rate and selectivity of the reaction. In summary, the [OMIM]Br has an excellent catalytic effect on the reaction. Notably, the [OMIM]Br is a nonvolatile compound, which have the advantages environmental friendly and nontoxicity.关键词：ionic liquid;catalysis;halogenation;fatty alcohol-polyoxyethylene ether chloride;fatty alcohol-polyoxyethylene ether
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发布时间：2023-11-14 - 摘要：Abstract:Abstract: In order to improve fatigue performance of asphalt rubber mixture, firstly, different ratio of CR-SBS modified asphalt was produced by compounding asphalt rubber with SBS. Then, powder composite modified asphalt mixture was prepared through mixing with basalt fiber in the form of ‘dry mixing’, and had fatigue test on it. Fatigue and stiffness modulus of 14 kinds of asphalt mixture were comprehensively analyzed to evaluate the ability of anti-fatigue cracking and self-healing by four-point bending fatigue life test. It turned out that the asphalt binder, adopting optimal proportion of 14% rubber powder and 2% SBS of matrix asphalt, has significantly better fatigue properties than other proportion of asphalt binder at different temperatures; Fatigue life of mixtures II is maximum, VII next, and both are much larger than the others; Fatigue recovery rates of mixture VII is maximum, AR andⅡnext; Stiffness modulus recovery rate of mixture VII is maximum, II next. Therefore, mixing right amount of SBS modifier and basalt fiber in rubber asphalt mixture can gain a strong sense of fatigue life and the most powerful self-healing compensation capacity, and the optimal quality proportion is masphalt：mCR：mSBS=100：14：2与mmineral aggregate：mBF=1000：3.关键词：road engineering;rubber powder composite modifier;asphalt mixture;fatigue performance;basalt fiber
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发布时间：2023-11-14
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