最新刊期
卷 41 ， 期 4 ， 2009
- 摘要：Abstract:Cascade project of Three Gorges and Gezhouba is an important project for downstream Yangtze river basin, and operation jointly of cascade project of Three Gorges and Gezhouba is not only the basic and example of sustainable water resources utilization of downstream Yangtze river basin, but is the necessary condition to realize overall hydrology compensation, storage compensation, power compensation and improve reliability of systems and synthesized benefits, thus, it is necessary to learn the status and progress for discussing the problem of hydrology, operation, and so on which the operation techniques integration on cascade project of Three Gorges and Gezhouba involves. On the basis of discussing on significance of operation techniques integration on cascade project of Three Gorges and Gezhouba, relative research of automatic measure and report system of meteorological water information, cascade operation of river basin, dynamical control of water limited level during flood season, ecological operation for huge reservoir and examination of special huge hydropower are analyzed and the problem need to solve quickly are pointed within this task which give the guidance for this task and the same study and practice.关键词：project of Three Gorges and Gezhouba;cascade operation;dynamic control of water limited level during flood season;ecological operation;hydropower examination
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发布时间：2023-11-28 - 摘要：Abstract:With the construction of large water-power engineering projects in alpine and canyon area, the stability of surrounding rock and stress deformation of lining under outer and inner water pressure becomes important. The excavation and supporting of surrounding rock, interaction between surrounding rock and lining, behavior of reinforced concrete were modeled. Then the stress and deformation of surrounding rock, reinforcement of lining material, stress and crack in reinforced concrete bifurcation structure were analyzed in the project of Pushihe pumped-storage power station. Calculation result of surrounding rock show that: tension stress zone mainly exist in connection region of main tunnel and bifurcation tunnel, plastic zone developed in connection region and region of main tunnel that adjacent to the bifurcation tunnel, bifurcation tunnel also has plastic zone. Calculation result of bifurcation structure show that: during error-free running work condition most region of the bifurcation structure exist tension stress, crack width is large; during overhaul work condition tension stress only exist in connection region of main tunnel and bifurcation tunnel, crack width is small.关键词：reinforced concrete bifurcation structure;Surrounding rock;stress;crack width;finite element analysis
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发布时间：2023-11-28 - 摘要：Abstract:Hydrodynamic pressure will be produced from interaction and intercoupling between dam and reservoir during earthquake.Arch dam will subjected to impact action from hydrodynamic pressure.Air isolation technique has been applied to decrease hydrodynamic pressure and to improve shock resistant capability of arch dam. Based on the theory of fluid solid interaction, tridimensional FEM model of dam air water is introduced. Research of seismic isolation mechanism on air cushion has been formulated.Tridimensional dynamic FEM simulation for gravity dam and arch dam was accomplished respectively.It is demonstrated that air isolation obviously influences hydrodynamic pressure and acceleration response.The hydrodynamic pressure is reduced for 65% with air cushion isolation. In addition,more model tests are needed to be verify air isolation mechanism.关键词：air isolation;dynamic FEM;hydrodynamic pressure;arch dam
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发布时间：2023-11-28 - 摘要：Abstract:Many buildings suffered severe damage during the Mw8.0 512 Wenchuan earthquake, especially the Masonry structure buildings. Field reconnaissance was carried out in the epicentral region after the Earthquake. The damage styles of multi-story masonry structure buildings were presented and the reasons of all kinds of damage were analyzed in this paper. According to the performance of multi-story masonry structure buildings, it was observed that collapses of multi-story masonry school buildings were mainly due to insufficient bearing capability of walls between windows. If the multi-story masonry structure buildings were designed seriously following the codes and had satisfactory quality construction, the buildings (school and resident) have good performance. The shear resistance and compression resistance of masonry walls with tie-columns were much higher than those of masonry walls without tie-columns. This indicates that RC tie-columns not only can improve the ductility of masonry structures, but also can increase the shear and compression resistance. Crack orientation in the masonry walls varied widely due to effects of earthquake. Buildings with satisfactory seismic concept design generally performed well.关键词：Wenchuan earthquake;Multi-story masonry building;Damage;seismic design
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发布时间：2023-11-28 - 摘要：Abstract:The calculation of thermal stress and thermal crack propagation remains a tough problem for hydraulic structure engineering. Due to its node discretization and no-remeshing property, the EFGM (Element free Galerkin Method) is very suitable for simulating cracking problems. Based on the EFGM, the approach for calculating the thermal stress and thermal crack propagation is studied, and a diffraction method is presented to simulate the multi-line discontinuity as well as the contour integral method for SIFs (Stress Intensity Factors) calculation. Then a VC++ program is developed. Samples including a surface thermal shock problem, a straight side cracking plane problem and a slope side cracking plane problem are computed to validate the program. All results show good accuracy and reliability. Then taking a bottom-restrained concrete block suffering thermal stress as an example, the crack propagation is simulated by the proposed approach. Finally some key problems for crack propagation simulation are discussed.关键词：element-free Galerkin method;thermal stress;diffraction method;contour integral method;mixed-mode crack;crack propagation;stress intensity factor (SIF)
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发布时间：2023-11-28 - 摘要：Abstract:To study the influence of rainfall infiltration on suction, water content and deformation of loess subgrade slopes, artificial rainfall simulation tests were conducted for four times on a 9 m high loess filled subgrade slope of Pingliang-Dingxi Expressway in Gansu Province, China, and the total in-situ monitoring continued for a month. Monitored results show that rainfall infiltration leads to obvious increase in soil moisture and decrease in soil suction within the top 1m soil layer, which results in a reduction of effective stress and shear strength. Meanwhile, the development of gullies on slope surface results in larger infiltration of rainfall and as a result a further decrease in shear strength. The maximum rain-induced collapse deformation occurred at the toe of the slope where the compaction degree is the lowest, which may lead to a local subsidence and trigger a slide slope failure in the condition of continuance rainfall. In consideration of controlling collapse deformation, reducing rainfall infiltration and the loss of shear strength of soil, it seems quite important to increase compaction degree of loess subgrade slopes.关键词：loess subgrade slope;artificial rainfall;field monitoring;suction;deformation
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发布时间：2023-11-28 - 摘要：Abstract:To determine the relationship between power loss and crack width theoretically in distributed optic-fiber crack detection technology. The classical theoretical model of bend loss was modified by correcting curvature radius in this paper. The application range of classical theoretical model was extended and mechanics-optics coupling theory of distributed optic-fiber crack detection technology was completed. Numerical experiments and model experiments were carried out for 4 cases which involve two fiber types and two angles between fiber and crack. The results show that the thinner the fiber sheath and the smaller the angle between fiber and crack, the higher the sensitivity is. The numerical results are consistent well with experimental results, demonstrating that this modified model is effective and can be used as a theoretical tool for developing the distributed optic-fiber crack detection technology.关键词：optic-fiber sensing;crack detection;bend loss;mechanics-optics coupling
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发布时间：2023-11-28 - 摘要：Abstract:For the geotechnical engineering, rock is usually subjected to spatial stress state, so it is rather meaningful to study the mechanism of rock damage and fracture under triaxial stress contidion.The rock is heterogeneous material and its meso-mechanical property satisfies the Weibull random distribution. Based on random distribution of interior defect in rock, a statistical damage constitutive model for rock was developed by using the statistical theory subjected to confining pressure and external force. The statistical parameters in the constitutive model were solved by using triaxial compression of sandstone, and qualitativly analyzed the influence of confining pressure to critical damage. The results show: （1）The model can reflect the confining pressure effect and the variation law of the rock strength with the confining pressure; The way of determining the parameters indicated the physical meaning of the parameters of model;（2）The statistical parameters in the constitutive model were solved by using the characteristics of the full stress-strain curve of sandstone acting on the specific confining pressure. Different parameters were corresponding to different confining pressure;（3）The crical damge changed with the confining pressure and depended on the state of stress due to the loads acting on rock; (4) According to physical meaning for the distributed parameters m, m can judge the brittleness and 1/m can judge the ductileness for sandstone.关键词：confining pressure;external force;constitutive model;Weibull random distribution;critical damge;distributed parameters
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发布时间：2023-11-28 - 摘要：Abstract:An element initial stress method to calculate stress intensity factor of three-dimensional mixed-mode crack was introduced, which adopted the degradation of the 1 / 4 node singular element to get the stress intensity factor from calculating the stress of the prime point stress about the crack tip When a cylinder buried inside the circular ramp crack under far-field equal tensile force was calculated by this method, compared with exact solutions, the relative error of the stress intensity factor numerical solution, the maximum relative error of KI was 1.44 percent. the maximum relative error of KⅡ was -2.30 percent. the maximum relative error of KⅢ was -1.22 percent. This method was worth promoting, because it was more exact, simple and propitious to calculate the stress intensity factor of mixed-mode three-dimensional crack problems.关键词：mixed-mode three-dimensional crack, stress intensity factor, 1/4 singular element, the best stress points, element initial stress method
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发布时间：2023-11-28 - 摘要：Abstract:It is convenient to separate the apartment in any way in this new residential system, which named unbonded prestressed slab—special-shaped columns or shear walls residential structural system. In order to study the seismic behaviors, using SAP2000 to make Pushover analysis in a series of numerical models, which are designed based on Chinese code. Some important parameters are considered in these models, such as prestressed effect, seismic fortification intensity, horizontal force distribution and stories. Some important behaviors are discussed, such as performance points, force-displacement curves and the distribution and development of plastic hinges in structures. The research results show that the regular residential structures with not more than 12 stories can work well in the region with seismic fortification intensity of 8 degree and below.关键词：Structural analysis;Residential structural system;Unbonded prestressed slab;Pushover analysis;Special-shaped columns;seismic behavior
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发布时间：2023-11-28 - 摘要：Abstract:Traditional method of determining the maintenance time of a structure system was to consider it as a non-deteriorating system. Actually, the whole life-cycle of structures fits the characteristics of deteriorating system, so establishing the maintenance strategy of deteriorating system has a significant engineering meaning. Based on characteristics of the deteriorating system, the differences between deteriorating structural systems and non-deteriorating structural systems were discussed in the paper, and the mathematical availability model and optimal maintenance strategy model has been deduced for deteriorating systems. Based on reliability theory, a mechanical model of the deteriorating structure’s failure mode was established, which adopts the minimum life-cycle cost strategy as the objective function. The optimal interval check time of deteriorating structural systems was obtained. A dam in Shandong province as an example was studied, a cost-check time curve was obtained. Some useful conclusions were given through analyzing.关键词：deterioration system;dam;availability;reliability;decision;optimal inspection interval
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发布时间：2023-11-28 - 摘要：Abstract:Large model tests were conducted on reinforced gabion walls filled with red sandstone under horizontal seismic loading to investigate the seismic response of walls. A series of tests were performed with different input seismic wave kinds and amplitudes. The dynamic characteristics and dynamic responses of model wall under horizontal seismic loading were discussed. Results show that reinforced gabion structure is excellent anti-seismic structure. There is significant amplification effect of input acceleration in reinforced gabion walls. The increment slope of horizontal acceleration magnification times is flatter with the wall height. With the high wall increased, there is an augmentation trend to horizontal acceleration. The magnification of lateral acceleration for each particle in wall is 1~1.88 under HACHI＿EW loading, and 1～2.78 under HACHI＿EW loading. The magnification times of lateral acceleration tend less obviously with the increase of amplitude, and the whole change shows a mainly linear stage. Vertical acceleration peaks both in the wall face and at the top of the wall increase greatly, reaching about the 44% to 56% of lateral acceleration peak of table. The vibration equation of vertical dynamic earth pressure of reinforced gabion wall under horizontal seismic loading is also derived.关键词：reinforced gabion walls;dynamic response;double twisted hexagonal wire mesh;red sandstone
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发布时间：2023-11-28 - 摘要：Abstract:Based on the equilibrium matrix theory and optimization theory, the design method of the prestress force of suspen-dome structure was presented. Then dynamic properties of the suspen-dome structure were investigated by the modal analysis with different prestress force values and different section of the upper single-layer dome. At last, the earthquake response analysis was carried out to discuss the basic behavior of the suspend-dome under earthquake loading and the dynamic responses between the single-layer dome structure and suspen-dome structure were compared. The results show that the natural frequencies of the suspen-dome will increase when the prestress forces of the cables increase. And the effect of the prestress force on the natural frequencies of the suspen-dome structure becomes smaller while the stiffness of the upper single-layer dome increases. The tensegric system (cable-strut system) of suspen-dome structure decreases the maximum stresses in most of elements by comparing the results of the seismic analysis of the suspen-dome structure and single-layer structure.关键词：suspen-dome structure;prestress force;dynamic analysis;modal analysis;seismic analysis
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发布时间：2023-11-28 - 摘要：Abstract: In order to study the mechanical behavior of soil-structure interface under the constant stress increment ratio stress paths, the simple shear tests of interface between high plasticity clay and concrete face were carried out, from the tests, the stress-strain relation curves under different stress paths were obtained. Five main phenomena were found, firstly, the high plasticity clay could well suitable to large deformation, and had strain-hardening behavior obviously, as well as, the little dilatancy; secondly, there was no correlation between stress paths and shear strength but the stress-strain relations were influenced by stress paths; thirdly, the little stress increment ratio, the higher increase speeding of shear stress and breaking strength under the condition of same initial normal stress; the fourth, the relations between normal strain and normal stress in simple shear test was consistent with which in the single-direction compression test, if there was no dilatancy; the last, the curve of relation between stress ratio and shear strain could be well simulated by hyperbola. Based on the test result and generalized potential theory, a bi-potential surface elasto-plastic model for soil-structure interface was created, in which the soil-structure interface problem was regard as a two-dimensional mathematical question in stress field, and plastic state equations were used to replace the traditional field surface. Studying shown that the proposed model which could reflect the infection of stress paths and initial normal stress on mechanical behavior of interface had a universal character and could be used in FEM, so it was good to be promoted and applied in the interface studying field.关键词：interface;simple shear test;stress path;shear strength;high plasticity clay;constitutive model
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发布时间：2023-11-28 - 摘要：Abstract:In order to understand PHC pile profoundly and extend its application, based on optimized fitting of actual measurement data of 11 field testing piles in 3 sites, some uplift characteristics of PHC pile were studied.. Aiming at the bearing characteristics of PHC pile, Weibull mathematical model was selected and optimized fitting analysis of uplift load versus uplift displacement curves was carried out. The fitting results of 11 field testing piles with the model showed that the fitting precision was high, the correlativity coefficients R was 0.98877~0.99963, the average value was 0.99861.The fitting effect with the model was better than the hyperbolic model and exponential model. The error between calculation value and field measure value of uplifting load of PHC piles based on fitting equations was ; the uplift displacement of PHC piles was 5mm~17mm in certain two engineering when uplift reach ultimate state based on fitting curves; comparison between uplift load and compression load of PHC pile, between PHC pile and steel pipe pile was carried out based on fitting results. The following conclusions can be drawn that the Weibull mathematical model is accurate and credible for fitting of uplift load versus uplift displacement curves of PHC piles and PHC pile is a excellent pile.关键词：Weibull mathematical model;uplifting load versus uplifting displacement curve;PHC pile;field loading test data
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发布时间：2023-11-28 - 摘要：Abstract:GLUE(Generalized Likelihood uncertainty Estimation) is a very wide-used methodology for uncertainty analysis of hydrological model. How to select an appropriate likelihood measure is still an open question so far. Usually the Nash-Sutcliffe coefficient is a traditional likelihood measure, but this measure focuses on the global performance without a special assessment in point condition especially for flood peak. A multi-criteria likelihood measure is presented within GLUE methodology, which consists of peak forecast error, runoff error, peak time error, and Nash-Sutcliffe coefficient. Based on the DHF(Da Huofang)model, it was applied to Biliuhe catchment. Forecasting error analysis was deduced. The results show the multi-criteria likelihood measure has improved compared with the original measure in describing the real uncertainty of model, which is very valuable for model calibration and uncertainty study.关键词：flood forecasting;uncertainty analysis;GLUE;multi-criteria likelihood measure;DHF(Da Huofang) model
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发布时间：2023-11-28 - 摘要：Abstract:A new TOPSIS model which based on the gray correlation coefficient matrix was presented in order to overcome the deficiency in more indicator of decision-making process. The method took the gray correlation coefficient matrix between primitive data sample and ideal scheme as new decision-making matrix，and then TOPSIS was used to evaluate and arrange all schemes. This method overcame the traditional TOPSIS shortcoming of excavating the inherent law of the data difficultly. Meanwhile, AHP and entropy methods were used to decide the weight of every decision-making index. This overcame the subjectivity or objectivity of traditional entropy decision methods. The new evaluation model was used in water quality in this paper. The result of application adapt to the evaluation of water quality.关键词：gray correlation coefficient matrix, TOPSIS, combinatorial entropy weight,water quality evaluation
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发布时间：2023-11-28 - 摘要：Abstract:When sediment-laden flow met clear water, it would dive into the bottom and kept on moving forward under particular condition because of its high density. Such Flow was a special form of sediment movement and named as density current. Based on the water-sediment two phase flow theory, this study Treated the turbid water as one phase homogeneous pore fluid. By sloving the ASM（Algebraic Slip Mixture）model , which included momentum, continuity equations for the mixture, the volume frraction eauations for the secondary phase and algebraic expressions for the relative velocities, the water-sediment two phases flow could be solved by such ASM model coupled with standard k-ε equations. This paper also introduced the relative verification test and multiphase experiment flume. By the analysis of the test result and applicability of the model, the conclusion had been made. Such coupling model can effective simulate the flow diving, head morphology and advance speed and more accurate for the situation of Re number above 2000 and sediment concentration above 1kg/m3. This study would provide a new method for the density current research relative to reservoir, lake and river entrance.
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发布时间：2023-11-28 - 摘要：Abstract:In this paper six carbazole oxime ester derivatives were synthesized through Friedel-Crafts acylation, oximation and esterification from N-alkyl-carbazole. The optimal operation condition of Friedel-Crafts acylation for product Ⅰ was determined by orthogonal experiment: 0.02mol N-ethyl- carbazol, n Benzoyl chloride/n N-ethyl- carbazol=1.2, n AlCl3/n N-ethyl- carbazol=1.2 , at 25 oC for 3.5h. The yield was 94.6%. The structure of the target compounds was characterized by 1HNMR, IR ,UV and elemental analysis. Photoinitiativity of the products was studied .
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发布时间：2023-11-28 - 摘要：Abstract:Porous nanosized CHA/β-TCP biphasic bioceramics were prepared by microwave plasma sintering in a wet carbon dioxide atmosphere to improve its biological and mechanical performance. Through the optimization of sintering parameters including the sintering temperature and the holding time, porous bioceramics with average crystal size of 92nm, porosity of 55.9%, CO32- content of 4wt% and compressive strength of 13.7MPa were obtained. The comparison between conventional sintered specimens and microwave plasma sintered specimens showed that the latter exhibit smaller crystal size and higher carbonate content and compressive strength. Microwave plasma sintering is a promising method of preparing nanosized bioceramics.关键词：carbonated hydroxyapatite;β-TCP;bioceramics;microwave plasma sintering
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发布时间：2023-11-28 - 摘要：Abstract:The interactions of collagen, with polyphenol and aldehyde, have been investigated using a number of analytical techniques such as DSC and size distribution. The collagen was simulated with hide powder. The stable Matrices can be obtained by polyphenol and aldehyde materials, and high resistance to thermal stability of Matrices can build high thermal stability to collagen. The results also showed that amino groups had more important influence to thermal stability of collagen than that of carboxyl groups. And the size distribution of Matrix formed by poly catechin-oxazolidine is 30 to 50 nm, which can supply high thermal stability for collagen.关键词：collagen;hydrothermal stability;polyphenol;aldehyde
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发布时间：2023-11-28 - 摘要：Abstract:A general method to separate and quantify simultaneously 6 active ingredients (arteannuin, rutin, isoquercitrin, salicylic acid, quercitrin, quercetin) in traditional Chinese medicine: Artemisia annua L. was established by high performance liquid chromatography (HPLC), this method has a wide linear range, low relative standard deviation, high precision and perfect reproducibility. Optimized apparatus condition was explored: An Tiahhe Kromasil C18 100 A (5μm，250 mm×4.6 mm) reversed-phase column was applied under 30℃; the wavelength of ultraviolet detector was set at 279nm; mobile phase was double-distilled water contained 50% (V/V) methanol and 0.02% trifluoroacetic acid (TFA) with a flow rate of 0.5ml/min in the performance. Compared with evaporative light scattering detector, ultraviolet detector had a high sensitivity to all ingredients except arteannuin in the experiment.
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发布时间：2023-11-28 - 摘要：Abstract:Wool-Fe (III) complex (Wool-Fe) was prepared by a reaction between a wool fiber and ferric chloride at room temperature and characterized using SEM and FT-IR, and then used as a heterogeneous catalyst for the degradation of azo dyes in water. Some factors affecting the degradation of azo dyes such as catalyst dosage, catalyst loading (CFe-wool), irradiation intensity, solution pH and dye structure was investigated with respect to the decoloration percentage and rate constant. Additionally, the photocatalytic degradation of azo dyes was examined by UV-Vis spectrum. The results indicated that wool fibers were able to coordinate with ferric ions in solution, and elevation of temperature and increasing ferric ion concentration led to the high CFe-wool catalysts. Moreover, increasing catalyst dosage and CFe-wool significantly accelerated the dye degradation. Wool-Fe catalyst showed high photocatalytic activity at pH≤6.0 solution, however, its activity was reduced at alkaline medium. Photocatalytic degradation of azo dyes in the presence of Wool-Fe catalyst followed the pseudo-first order kinetic model, and increasing catalyst dosage and CFe-PAN also enhanced the degradation rate constants. Reactive dyes were decomposed more easily than acid dyes in the presence of Wool-Fe catalyst and H2O2 at the same conditions.关键词：Wool fiber;Ferric ion;Heterogeneous photocatalyst;azo dye;degradation
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发布时间：2023-11-28 - 摘要：Abstract: The ternary hybrid systems of PVA/APP/LDH were prepared through addition of flame retardant, ammonium polyphosphate (APP), and flame-retardant synergist, layered double hydroxide (LDH) so as to improve flame retardancy of PVA. The rheological behaviors of flame-retardant PVA/APP/LDH hybrid systems were investigated using parallel-plate rheometer. The shear-thinning phenomenon occurred in the hybrid systems within the whole frequency range studied. When the concentration of PVA in aqueous solution was 9% and its proportion was 85wt% in the PVA/APP/LDH system, the complex viscosity of the hybrid systems increased first and then decreased as the proportion of LDH increased from 1wt% to 3wt%. According to the analysis of the rheological parameters and plots including the storage(G’) and loss modulus(G”), dynamic loss tangent (tan δ), Cole-Cole plot, relaxing time, etc, it can be concluded that the viscous rather than elastic rheological behavior is dominant, namely G”> G’ and tan δ>1. Thereby, the rheological behaviors of PVA/APP/LDH system were more complicated than PVA and PVA/APP systems.关键词：poly(vinyl alcohol);layered double hydroxide;hybrid systems;rheological behaviors
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发布时间：2023-11-28 - 摘要：Abstract:In order to discuss the applicability of weak-link scaling to predicting tensile strength a methodology based upon progressive damage mechanism coupling Monte-Carlo simulation technique, by considering statistical particularity of fiber strength, was developed to analyze the tensile strength distribution of fiber-reinforced composites under thermo-mechanical loading. The results indicated that weak-link scaling worked very well with β =10 when the composite size was more than 25 fibers. When the composite strength get to be convergent, the strength distributions for bigger specimen can be predicted through weak-link scaling. It is concluded that materials must, for sufficiently large sizes, have strength distributions that obey weak-link scaling. This investigation can provide the theoretical basis for fatigue life modeling of composites under cyclic loads based upon micromechanical analysis of damage.关键词：fiber-reinforced composite;tensile strength;Weak-Link scaling
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发布时间：2023-11-28 - 摘要：Abstract:The regression accuracy of the support vector regression (SVR) models depends on a proper setting of its parameters to a great extent. An optimal selection approach of v-SVR parameters was put forward based on chaos particle swarm optimization (CPSO) algorithm. Then a model based on v-SVR to predict the silicon content in hot metal was established, and the optimal parameters of the model was searched by CPSO. The data of the model were collected from No.3 BF in Panzhihua Iron and Steel Group Co.. The results showed that the proposed prediction model has better prediction results than neural network trained by particle swarm optimization and v-SVR, the percentage of samples whose absolute prediction error is less than 0.03 when predicting silicon content by v-SVR model is higher than 90%, it indicated that the prediction precision can meet the requirement of practical production.关键词：support vector regression;particle swarm optimization;chaos;silicon content in hot metal;prediction
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发布时间：2023-11-28 - 摘要：Abstract:ZnO:Eu3+,Li+ nanopowder was prepared by mechanochemical process and thermal decomposition. The obtained samples were characterized using TG-DSC, XRD, SEM, TEM. Results showed that Eu3+ and Li+ ions were successfully doped into the crystal lattice of ZnO matrix.The obtained powders exhibited normal size distribution, whose size were about 50nm. The main emission peak in ZnO:Eu3+,Li+ nanocrystals was 611 nm.The photoluminescence intensity of samples were interrelated with thermal decomposition temperature, ratio of Li and Eu.
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发布时间：2023-11-28 - 摘要：Abstract: In this paper, firstly, changes the systems of time-hopping BPSK in UWB into a virtually linear model, secondly， writes least square criterion , one of the optimal criterion of adaptive filtering algorithm, into matrix form, and proposes a new adaptive multi-user detection algorithm by using recursion of Moore-Penrose Inverse Matrix to the code matrix for each user which can be defined based on its unique TH sequence. After following LS recursion of Moore-Penrose Inverse Matrix optimization procedures, the desired signal can be detected from the adaptive multi-user detection algorithm. Numerical examples illustrate the performance of the LS detector versus that of the conventional single-user UWB detector and the performance of LS adaptive filtering algorithm is better than the RLS algorithm.关键词：UWB;Least Square Criterion;TH-BPSK;MUD;Recursion of Moore-Penrose Inverse Matrix
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发布时间：2023-11-28 - 摘要：Abstract:A robust method for 2.5D facial shape and texture reconstruction based-on the model of polyhedron and the technology of photometric stereo was presented. Using the continuity restrictions and error-reduced operator, the presented method can overcome the influence of shadow, highlight and hair. The 2.5D shape and texture of human face was reconstruction firstly by solving a linear equations system, which was established by the corresponding relationships between faces of polyhedron and pixels of human facial images under three independent illuminations. Then, three virtual photometric stereo images were synthesized from reconstructed results using computer graphics. The local shadow analysis and specular reflection are used to make the synthesized images approach to the real images. Facial shape and texture were reconstructed again from synthesized virtual photometric stereo images. Finally, these two reconstruction results are combined to reduce the reconstruction error and produce a superior result. A fragment shader based-on GPU was presented to accelerate computation process. Experimental results on YaleB database show that this method can reconstruct the 2.5D shape and texture of human face rapidly and robustly.关键词：2.5d face reconstruction;model of polyhedron;GPU acceleration;error reduction;photometric stereo
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发布时间：2023-11-28 - 摘要：Abstract:Using the P2P model to scheduling the grid job among the multi-cluster, it not only enhances the grid system scalability and fault-tolerant, but also turns each cluster into an autonomous scheduling unit and completes their job cooperatively. The system integrates the Globus grid middleware system and the OpenPBS, and increases assisted scheduling services, which makes grid job migrate among the multi-cluster and eases effectively the load of job in a single cluster.关键词：mulit-cluster;P2P scheduling;Grid;Globus
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发布时间：2023-11-28 - 摘要：Abstract:In order to overcome the flaw in the Xiao scheme on conic curve over Zn, of which the published parameter Nn could make it possible that the modulus n could be factorized, an improved scheme was proposed here. In our proposed scheme, the parameter Nn was kept secretly, and the verifying algorithm was presented. Moreover, generalized conic curve was chosen to replace conic curve. The security analysis showed that the improved scheme is easy to accomplish for convenient embedding plaintext, computing element order and points in the generalized conic curve. In addition, this scheme is a digital signature scheme based on computing discrete logarithm and factorizing great integer, and has more curves for choice than it on conic curve.关键词：digital signature;integer factorization;discrete logarithm;generalized conic curve
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发布时间：2023-11-28 - 摘要：Abstract: The Medium-Field multivariate public key encryption scheme given by Wang et al in the 2006 RSA conference was defeated by the SOLE (second order linearization equation) attack presented by Ding et al. An improved scheme was proposed. The central map of the original scheme was redesigned and the related linear equations can not be calculated by the attacker, and then the new variant can avoid the SOLE attack. Analyses show that the enhanced variant can resist the SOLE attack, Rank attacks, and Gr bner-based method. Therefore it is a more security multivariate public key encryption scheme.关键词：cryptanalysis;public key cryptography;multivariate;linear equation;Medium-Field
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- 494
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发布时间：2023-11-28 - 摘要：Abstract:To date, some identity based strong designated verifier signature schemes have been proposed, but there are some drawbacks on these schemes. To overcome the problem above, in this paper, a novel identity based strong designated verifier signature scheme is proposed from bilinear map. The proposed scheme is secure in the random oracle model under the bilinear Diffie-Hellman assumption. From the performance comparison with the existing schemes, it can be concluded that the proposed scheme has lower computational cost and shorter size of signature.关键词：Strong designated verifier signature;identity based;bilinear map;BDH problem
- 2660
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- 358
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- 3
发布时间：2023-11-28 - 摘要：Abstract:Traditional Digital watermark is robust against compression, but can barely remain the stability to resist geometric attack. In this paper, we advance a watermarking method based on wavelet domain data block which may make up the defection of the traditional methods. It is based on the transformation, rotation and scale invariant of the local linear embedding, embedding the watermark sequence into wavelet domain data block’s locally liner embedding reconstruction weight factor, rather than pixel value or transformation factor. Therefore, the algorithm can remain robust against cropping. As the result of the experiment, the algorithm will not increase the information volume of the watermark sequence, but can improve the robustness against the transformation, scale, rotation attack and can reduce the demand of the original image.关键词：wavelet domain data block, locally linear embedding, embedding information volume, affine transformation invariability
- 3239
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- 380
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发布时间：2023-11-28 - 摘要：Abstract: To take the use of natural language part of speech tagging in text information hiding research, the order relation and its transforming property were studied. A proper partial relation was defined in the collection of part of speech tagging firstly，and then a tagging string could be reflected as 0 and 1 by calculating the odd and even characteristic of the inverse order of it. Research shows that the corresponding binary sequence of the casually selected tagging strings had a better self-relation and co-relation property whose normalized relation coefficients were round 0.55, it sounds reasonable to distinguish various templates, so a new method by using the odd and even characteristic of the inverse order to hide information was proposed. And the inverse order has also been proved to have an odd and even characteristic under the condition of being exchanged, added and deleted. This method is robust against the attacking of synonyms replacement.
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- 244
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发布时间：2023-11-28 - 摘要：Abstract:In order to improve the recovery efficiency of archives, a method of reverse differential archive is proposed． The archiving task is achieved by calculating the reverse difference set and reconstructing the latest files with differential files. In the process of file recovery, the reverse differential files are used to recover the file needed based on the time of the reverse. The experiment results indicate that this method can decrease recovery time remarkably，and improve efficiency of file recovery evidently over traditional file archive．关键词：file archive;reverse difference calculation;file reconstruction;file recovery;rsync
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- 314
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- 3
发布时间：2023-11-28 - 摘要：Abstract: To research the formation law of network public opinion, from the angle of theory of Complex Adaptive System (CAS) and started from the constitution of public opinion, this article introduced the concept of Incline Degree of Opinion of Agent for the first time, and analyzed the related factors influencing the changes of incline degree of opinion of agent and set up the rules for the changes. The authors then established a model with the influence of Agent, debating efficiency, self-supporting capability, active flag and the influences of mainstream media and law as the independent variables to explain the formation of network public opinion. Finally simulation experiments were carried out after simplifying this model and the experiment results were analyzed.关键词：incline degree of opinion, network public opinion, formation of network public opinion, mathematical model, CAS
- 2423
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- 318
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- 2
发布时间：2023-11-28 - 摘要：Abstract: One novel slicing triangulation algorithm was proposed, which dose not need manual intervention and can triangulate both overlapping and non-overlapping points cloud highly efficiently. The algorithm contains two main stages: points cloud preprocessing and triangulation. In preprocessing phase, the information of KNN、vector and shape index are extracted from points’ location information; In triangulation stage, if one new basis point is picked out, one new patch will be created based on the orientation angle between the basis point and each other unprocessed point, then the patch is projected onto the basis point’s tangent plane and triangulated, after verifying triangles in 3D space, the triangulation results of the patch are saved. Final triangulation results are output until there is no new basis point available. The experiment results confirm the proposed algorithm is effective and highly-efficient.关键词：surface reconstruction, normal vector, k-nearest neighbors, triangulation, orientation angle
- 2633
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- 332
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- 2
发布时间：2023-11-28 - 摘要：Abstract:To better apply FEA technologies in rapid product development, viewing on the design process knowledge reusing, a knowledge fusion based method is worked out to analyze and optimize product structure. The dynamic analyzing process template is brought into design activity, which can be used to optimize product solution for more developers, and to parameterize the product modeling, meshing and analyzing. Therefore, the product developing knowledge and optimizing method of enterprises can be accumulated constantly by themselves. This method is applied to develop some kind of straight bevel gear in differential case. First, the stress concentration area is found, and the unreasonable expanding mechanism is corrected. Second, the design of bevel gear is optimized to improve the carrying capacity of base. Then the fracture failure rate would be cut down. From experiments, the results show that this method makes for popularizing application of FEA technologies at the higher lever among in all developers.
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- 382
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- 1
发布时间：2023-11-28 - 摘要：Abstract:Aiming at the key technology problem which the hydraulic pulse produced by hydraulic impulse testing equipment reliably and be controlled, according to pipe-cubage model, ramp model was established and the response express of ramp input was deduced for the first time. The computation results reveal that the maximal excess is 63.7% in ramp model. Based on step and ramp model, ramp input can be treated as step input when the time of ramp input no more than tenth of system oscillation periods. Digital simulations of step and ramp model were carried out through Matlab software and electro-hydraulic assimilation method, and the simulation results show that standard pulse can be produced by means of adjusting system parameters, such as cubage, length of pipe and diameter of pipe and etc.关键词：Hydraulic impulse testing equipment;pipe-cubage model;Step input;Ramp input;electrohydraulic assimilation method
- 2518
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- 692
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发布时间：2023-11-28 - 摘要：Abstract:An attitude determination system consists of monocular computer vision, triaxial fiber optic gyroscope and two-axis inclinometer is presented. It aims to meet the demand of the five degrees of freedom air-bearing testbed according to actual situation. Ground computer captures images and recognizes pixel coordinates of indicating lamps on the air-bearing testbed, and then the yaw angle can be calculated by formula which derived in this paper. Tracking differentiator is used to reduce calculation region and can improve processing frequency from 7Hz to 12Hz. Based on Multiplicative Extended Kalman Filtering technique, an attitude determination algorithm is designed by using quaternion. The experiment result proves that attitude of the air-bearing testbed can be esti-mated and corrected accurately by this system.关键词：Spacecraft ground experiment;The 5-DoF air-bearing testbed;Image recognition;Tracking differentiator;MEKF
- 2868
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- 698
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发布时间：2023-11-28 - 摘要：Abstract:In this paper, on the basis of simulation model of standard mannequin, measuring the particual dimensions in a new measurement system for human body, the form changement character of each feature section is determined by comparing the ratios of some measurements. The coordinates of certain points on the contour of each feature section are calculated according to the construction character and the particual dimensions. The contour curves of feature sections are fitted by cubic splines, and other curves are determined based on the model of standard mannequin. The foundation of the individual mannequin with different shapes of are realized by VC++ and OpenGL. This approach is very usful in 3D garment design and demonstration.关键词：mannequin, feature section, cubic spline
- 2619
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- 154
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- 0
发布时间：2023-11-28 - 摘要：Abstract:The accurate evaluation and decision-making to product project is very importance in the design process. In this paper through contrasting the characteristics of current evaluation methods, incorporating least square method and Extenics theory, an extension evaluation model for multi-attribute product project is put forward. First the indexes weight are determined with F-AHP evaluation methods. Then the eigenvalue of evaluation index system are calculated with the multi-attribute correlation function of Extenics theory according to the corresponding attributes. A perfect performance function is established after balancing all indexes weight and the evaluation to product performances is done with iterative calculation. Finally, an evaluation process about a geneva mechanism was carried out to verify the validity of this evaluation model.关键词：Project evaluation;Multi-attribute correlation function;Performance goodness;Iterative calculation
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- 360
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发布时间：2023-11-28 - 摘要：Abstract:The H∞ filtering is introduced because KALMAN filtering accuracy is not high or even divergent issues when system model is uncertain or noise statistics characteristics are not accurate. H∞ filtering basic theory and recursive formulas are introduced and compared with KALMAN filtering in essence. The initial alignment model of 12-dimensional states is established and is simulated compared with KALMAN filtering under the conditions of white noise and color noise. Three representative parameters γ were selected for compared simulation in order to illustrate the impact of the selection of γ at the speed and accuracy of initial alignment. The simulation results show that in the circumstances of white noise the accuracy of two filter almost the same but KALMAN filter is slightly better. In the circumstances of color noise the anti-interference of H∞ filter is obviously stronger than KALMAN filter. At the same time, the average performance (accuracy) and robust performance of the system are balanced by selecting the parameter γ properly.关键词：SINS;Initial alignment;filtering;KALMAN filtering
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- 330
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- 1
发布时间：2023-11-28 - 摘要：Abstract:In order to decrease the hardware complexity of DWT further, an efficient hardware structure for DWT derived from flipping scheme was proposed. The precision of hardware structure had been analyzed, moreover, dynamic range and number of binary factional bit had been obtained. The structure merged the lifting step and adopted the pipelined design to combine predictor step and updater step into one single lifting step, and adjust the primitive data path effectively. The structure introduced 2 to 1 multiplexers into scaling step. Experimental results shown that the proposed structure, under the tight critical path, could effectively reduce the quantity of multipliers, adders and internal registers, and make full use of the arithmetic resources.关键词：DWT;flipping structure;lifting step
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- 166
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发布时间：2023-11-28
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