最新刊期
卷 42 ， 期 4 ， 2010
- 摘要：Abstract:The ventilation of Xiangjiaba underground powerhouse is very difficult, and the traditional ventilation design maybe result in poor effect and resource waste. In order to resolve these problems, the optimization model of ventilation scheme was proposed based on dynamic simulation and numerical simulation. By this model, the variability and the dynamic characteristic of needed wind quantity can be considered and the flow field can be simulated. The results showed that this method can provide the theoretic proof and technical support for the ventilation design.关键词：Xiangjiaba Hydropower Station;underground tunnel-chamber group;construction ventilation;dynamic simulation;numerical simulation
- 2880
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发布时间：2023-11-14 - 摘要：Abstract:Two kinds of test-blocks on concrete joints of trapezoid and arc were made by the method in which one half of test block was cast firstly, and the other half was cast a month later. Concrete joints impermeability test was carried out using existing test instrument, and impermeability grade of the test blocks was determined. Test result showed that both impermeability grades of concrete joints for trapezoid and arc can arrive at S2, have impermeability effect in some degree; the trapezoid-joint impermeability is slightly better than the arc-joint. The method can be a reference to amendment of correlative criterion.关键词：concrete construction-joint;mechanical permeability;testing;waterproofing
- 2776
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- 4
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发布时间：2023-11-14 - 摘要：Abstract:According to the characteristics of hydraulic fracturing of rock mass and concrete fracture under natural power, the water infusion model and iteration procedure of rock or concrete fracture under constant water head were built based on the cube law of water moving in fracture. The different infusion processes were calculated by changing opening width, inner surface off set and shape of fracture. The results showed that the water moving in fracture is fast in initial infusion stage, and slow in final. The water pressure along the fracture is gradually developed to full pressure as lapse. When the opening width of fracture is larger than 0.02 mm, there is shorter time to arrive tip and the pressure along the fracture is a whole head. When the opening width of fracture is micrometer, it is difficulty to fill fracture, which is an impermeable fracture. The influence of fracture water pressure on relative smaller opening width fracture due to inner surface off-set is more significant than that with wider opening width of fracture.关键词：rock;concrete;fracture;water infusion process;pressure distribution
- 2825
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- 16
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发布时间：2023-11-14 - 摘要：Abstract:Based on theoretical analysis and on-the-spot monitoring methods, a prediction system for rockburst consisting of long-term and short-term predicting models was proposed. The long-term predicting model adopted a wavelet neural network predicting model by using the rockburst materials of underground projects at home and abroad, so as to forcast the trend of rockburst. In the short term prediction model, a wavelet neural network model based on the Acoustic Emission(AE) monitored was established to forecast the future AE firstly, and then a catastrophe prediction model for rockburst was founded based on AE forecasted in order to forcast the rockburst near the monitoring site accurately. The two models both used wavelet neural network theory, and can enhance the rate of convergence and fault tolerant capability, and assure the effects of prediction. A practical example showed that the prediction system has high accuracy，and the prediction results accord with the field performances.关键词：rockburst;prediction system;long-term predicting models;short-term predicting models;Acoustic Emission(AE);wavelet neural network;catastrophe theory
- 3281
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- 16
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发布时间：2023-11-14 - 摘要：Abstract:An experimental system for the simulation of total dissolved gas (TDG) supersaturated water was developed, which created the supersaturated water by increasing pressure of equilibrated water. Multiple levels of gas saturation can be obtained simultaneously by mixing supersaturated water and equilibrated water. Testing results of the system indicated that the system is capable of operating under designated temperature and providing TDG supersaturated water with stable levels ranging from 100% to 145%. It exists significant linear relationship between the level of TDG supersaturation and pressure. Testing results also showed that the system can be controlled and repeated,and used to study the theory and mechanism of the supersaturated water generation and the effects of high dams on downstream aquatic ecosystem.关键词：dams;total dissolved gas;supersaturation;water;experiments
- 4240
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- 4
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发布时间：2023-11-14 - 摘要：Abstract: In order to overcome the problem that the physical model is difficult to measure flow forms and scouring characteristics in great unit discharge diversion channel, the turbulence model was used to calculate diversion channel flows and natural river flows. The results showed that the calculated values were in accordance with the experimental data. By comparing three types of velocity distribution characteristics under diversion channel, the flow field details was obtained.关键词：numerical simulation;VOF method;hydraulic characteristics;diversion channel;scheme optimization
- 2996
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- 2
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发布时间：2023-11-14 - 摘要：Abstract:The method of water free surface adapting grid system with 2D structured grids was extended to 3D unstructured grids to simulate phreatic surface in seepage flow. In this approach, the grid system does not need to be modified or regenerated during nonlinear iterations, whereas free surface is mapped to grid nodes to determinate the final phreatic surface without handling seepage face specifically. The good agreement of computations and experimental results indicated that this method can capture the phreatic surface in 3D unstructured grids with well precision. This study extended the application range of adapting grid method in unconfined seepage flow.关键词：seepage flow;phreatic surface;free surface adaping grid system;3D unstructured grids
- 3378
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发布时间：2023-11-14 - 摘要：Abstract:Regarding to the desorption of the soluble matter erosion in rivers, the currently used steady-state models including Herry model, Langmuir model, Freundlich model and Surface Complexation model for predicting the desorption quantity of soluble matters were summarized. Taking Ca2+ as the representative index of soluble matters and based on the static state experimental results, the validity of the above four models were checked. The comparison indicated that because the initial occurrence of soluble matters in desorption was greatly different from it in sorption, the diffusion process in desorption was not considered in any of the above models. Then by the analysis of the desorption mode of soluble matters, it was found that the desorption was an integrated process of diffusion and ion exchange. At last, the above models were improved in which the total desorption quantity of soluble matters was devided into diffusion quantity and ion exchange quantity.关键词：soluble matters;desorption;desorption model;comparison;improved model
- 2679
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- 6
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发布时间：2023-11-14 - 摘要：Abstract:A three-dimensional numerical model for solving JONSWAP waves and jets in σ-coordinate was developed using large eddy simulation technology, in which the dynamic coherent eddy model was used. The operator splitting method was used to solve the Navier-Stokes equations. After the model was verified with the experimental results of the jet in regular waves, the model was used to simulate the vertical turbulent jet in JONSWAP wave environments. Investigation was done for the distribution of the enstophy of the core of vorticity in the backzone. The mixing process was found to be governed by entrainment and jet-wave interaction. The mechanism of jet instantaneous characteristic in JONSWAP wave was also investigated. The numerical results are of great theoretical importance for the understanding of jet turbulent behaviors in JONSWAP wave.关键词：large eddy simulation;JONSWAP waves;turbulent jets;dynamic coherent eddy model
- 3372
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发布时间：2023-11-14 - 摘要：Abstract:In order to study the time-dependence of damage and degradation effect for soft rock under water corrosion, subcritical crack growth of soft rock was studied by double torsion test using Instron1342 type electro hydraulic servo test machine and the mechanics parameters test using RYL-600 rock test machine after marinated soft rock in water for different time. Based on testing results, the rate of water content(ω), the mechanics parameters, the subcritical crack growth velocity(V), the stress intensity factor(KI), and the fracture toughness (KIC) were obtained, respectively. The results showed that the rate of water content(ω) VS the time of water-rock interaction relations accord with good linear rule and could be used to establish the function relationship of damage and degradation velocity(D~) for soft rock by means of the rate of water content(ω)and elasticity modulus(E). The relationship of subcritical crack growth velocity(V)and stress intensity factor(KI) of soft rock in different time were studied by double logarithm coordinate, and the results showed that lgKI-lgV relations accord with good linear rule and the fracture mechanics effect of water corrosion action of swelling soft rock is evident and time dependent, and the water corrosion damage can accelerate subcritical crack growth velocity(V) and can weaken fracture mechanical characteristic of swelling soft rock.关键词：soft rock;water-rock interaction;damage;degradation;time-dependent;swelling
- 3090
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- 10
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发布时间：2023-11-14 - 摘要：Abstract:In order to study hydraulic environment required by the spawning grounds of four major Chinese carps in the middle reach of the Yangtze River, numerical simulation method was used to quantitatively analyze the morphological feature and flow characteristics of the spawning reaches. Hydraulic characteristics such as energy slope, flow regime, kenitic energy gradient, energy losses and Froude number were studied, and distributions of hydraulic elements in typical sections were analyzed using statistical method. The results showed that the four major Chinese carps spawning grounds have special characteristics, with special river morphology, obvious two-dimensional energy slope, complicated water flow regime, much energy loss, and small kinetic energy gradient and Froude number values in cross-section. This study could provide references for protecting the hydraulic environment required by the spawning ground of four major Chinese carps.关键词：river morphology;flow characteristics;spawning ground;four major Chinese carps
- 3191
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- 4
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- 12
发布时间：2023-11-14 - 摘要：Abstract:In order to accurately measure the internal deformation in geo-mechanical model test, Based on surrounding rock failure model test of deep roadway, fiber Bragg grating strain sensors and grating ruler displacement sensors were laid in the model to monitor the internal strain and displacement .At the same time, in order to analyze the deformation law comparatively, resistance strain bricks were laid in the model too. The results indicated thatthe internal deformation laws obtained by resistance strain bricks, fiber Bragg grating strain sensors and grating ruler displacement sensors are consistent, so the fiber Bragg grating strain sensor and grating ruler displacement sensor can be used to measure the internal deformation in the model test. The precision of the grating ruler displacement sensor can achieve 0.001mm, with the characteristics of simple making, strong stability and not easy to damage, therefore it can be widely used in the model test.The deformation laws obtained by the three measuring means which change between peak and trough coincide with phenomena of alternative appearance between failure zone and un-failure zone in the model.关键词：model test;roadway failure;internal deformation measurement;fiber grating;grating ruler
- 3399
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- 0
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- 3
发布时间：2023-11-14 - 摘要：Abstract:To decrease the numerical error in the engineering turbulence problem, which comes from the uncertainty of turbulence model, a Bayesian method was developed to identify the parameters for widely used k-ε turbulence model based on the back step flow. The method combines direct computation with finite element method and inverse computation with Metropolis-Hastings sampling algorithm, which can give the posterior distribution of standard k-ε model parameters once the velocity on some observation sites are known. Case computation indicated that after parameter identification the computation has a lower numerical error than that without parameter identification.关键词：k-ε turbulence model;parameter identification;Metropolis-Hastings algorithm;Bayesian inference;inverse problems
- 3875
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- 2
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- 2
发布时间：2023-11-14 - 摘要：Abstract:By analyzing the first generalized threshold signcryption scheme (WCL scheme) and its improved schemes (TJC scheme, etc.), it was found that they can’t resist several attacks such as equation attack and can’t realize threshold designcryption. In order to remedy their security flaws, a novel security enhanced generalized threshold signcryption scheme was presented. In the new scheme, the random factor was added to the secret parameter R so as to completely realize the function of generalized threshold signcryption, i.e.(t,n)threshold signcryption and(k,l)threshold designcryption, and by means of Chaum-Pedersen discrete logarithm equation knowledge protocol, malicious members’deceitful behaviors could also be detected. Security analysis and efficiency evaluation showed that this new scheme could resist all the attacks proposed in previous literatures and was more efficient than WCL scheme with respect to computation and communication costs.关键词：generalized threshold;threthold signcryption;threshold designcryption;discrete logarithm equation
- 2927
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- 0
发布时间：2023-11-14 - 摘要：Abstract:The Gene Expression Programming(GEP) usually exists some un-expressed introns,the performance may be lower than GA in simple function optimization and the speed is un-satisfied to complicated optimization task. To improve the expression efficiency of gene space and the performance for function optimization, an evolutionary algorithm EGEP (Embedded Gene Expression Programming) was proposed based on a new decoding method. A new coding method for individual was designed which was suited for function optimization. And the expression space of individual was analyzed. Experiments showed that EGEP is superior to GA in simple function optimization. Even if the run generation reduced by 200 times, the performance of EGEP still surpasses GEP and GA in complex function optimization.关键词：function optimization;Genetic Algorithm(GA);Gene Expression Programming(GEP);intron
- 3041
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- 0
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发布时间：2023-11-14 - 摘要：Abstract:The component-based model of dynamic evaluation was used to give a dynamic re-evaluation model.This model abstracts the information system to topological and combinational construction,reduces the connection between components into independent and collaborative relations, and the combinational relation of components into serial and parallel connection types. When the system changed, by only discussing the changed components and determining its change manner and impact scope, the rest of the components can be evaluated and the impact on the entire system can be assessed. Examples showed that the model breaks through the limitations of a traditional static one-time assessment and realizes the dynamic re-evaluation based on change.关键词：information security;risk evaluation;components;reevaluation;dynamic evaluation model
- 2284
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- 6
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发布时间：2023-11-14 - 摘要：Abstract:To improve the efficiency of resource locating in Peer-to-Peer (P2P) networks, and isolate malicious peers, a topology construction method for unstructured P2P networks called DPT was proposed.In DPT, each neighbor of a peer had a changeable TTL (time-to-live), the reliable TTL of each neighbor was changed by its transmitting condition after each interaction,and the transmitting condition of direct forwarding peers of query paths was also recorded.The method designed some structures to store peers’ transmitting information, and proposed algorithms to adjust the topology of P2P networks. Simulations demonstrated that the topology construction method of DPT can isolate malicious peers to the fringe of the network, and improve the efficiency of resource locating, enhancing the quality of service in P2P networks effectively.关键词：Peer-to-Peer;unstructured;topology;resource locating
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发布时间：2023-11-14 - 摘要：Abstract:In order to overcome several disadvantages of traditional RANSAC,a parallel improved RANSAC based on CUDA was presented. With guaranteeing the same confidence of the solution as traditional RANSAC，the proposed method parallelly dosed sampling， computed and verified model, and found out the most suitable parameters. Meanwhile，NVIDIA’s CUDA was chosen as parallel computation environment，and by exploiting the GPU’s hardware feature for general-purpose computing，GPU computational model of RANSAC was designed and implemented. Experiments showed that parallel improved RANSAC based on CUDA can overcome disadvantages of traditional RANSAC，and retain its simplicity and easy-to-use.关键词：parallel computing;robust estimation;RANSAC;CUDA
- 3298
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- 2
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- 2
发布时间：2023-11-14 - 摘要：Abstract:In order to solve the problem that the present integrity measurement scheme of TCG did not reflect runtime behaviors accurately, a noninterference integrity measurement model based on actions of system processes was proposed. By using the basic idea of noninterference theory as reference, the process operation integrity and the interprocess integrity transmission were analyzed, hence the runtime integrity of system can be measured from the dynamic point of view. Formal description and analysis showed that the model is intuitionistic, well understandable and can be realized by any method which meets the requirements of the model.关键词：information flow;noninterference;trusted computing;remote attestation;integrity measurement
- 2905
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- 0
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- 2
发布时间：2023-11-14 - 摘要：Abstract:In order to solve the session key agreement problem between a mobile user and a network control center, an authenticated key exchange protocol for mobile satellite communication systems which was proved universally composable secure at present was carefully analyzed. It was found that there was some mistake in the proof and the protocol was easy to suffer the data synchronization attack and the key compromise impersonation attack. Furthermore, improvements to overcome the security vulnerabilities of the protocol were proposed. The improved protocol was universally composable secure.关键词：mobile satellite communication systems;security;protocol;key exchange;universal composition
- 2906
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- 0
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- 0
发布时间：2023-11-14 - 摘要：Abstract:To simulate the visual search result of human, a new bottom-up visual attention model was proposed based on the graph theory. In textual model, the procession of getting salience map consisted of two steps. The first step constracted the markovian marix.The second one accounted the degree of every vertex in graph, which highlighted the salient area of maps on certain feature channel including colors, intensity and orientations. Experimental results showed that this model is more effective for target detection and has less calculating works than some others visual attention models.关键词：graph;visual attention;bottom-up;degree
- 3082
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- 0
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- 1
发布时间：2023-11-14 - 摘要：Abstract:To overcome the drawback that the diffusion tensor magnetic resonance imaging (DTI) is vulnerable to noise and the current method deals with the DWI separately in different directions which ignores the correlation of the structure information and characteristics of the DTI, a novel anistropic filtering method synthetically considering the structure information and characteristics of the DTI was proposed based on the correlation of DWI in different directions. The smoothing structure tensor with unified eigenvalue and eigenvector was reconstructed and the iteration process was constrained by the preserving parameter. By this method, denoising simulations using a synthetic DTI dataset and experiments using an in vivo brain DTI dataset were done. The results of the simulations and experiments demonstrated that this method could remove the noise significantly and is more effective compared with the traditional methods.关键词：diffusion tensor magnetic resonance imaging;anisotropic filtering;preserving parameter
- 3054
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- 4
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发布时间：2023-11-14 - 摘要：Abstract:To eliminate the adverse impact on filter precision which was brought about by the maneuvering multi-target tracking system's strong nonlinear and motion model switching in clutters environment, a novel maneuvering multi-target tracking algorithm based on multiple model particle filter was presented. The dynamic combination of multiple model particle filter and generalized probabilistic data association method was realized in the new algorithm. The rapid expansion of computational complexity, caused by the simple combination of the interacting multiple model and particle filter, was solved by introducing model information into the sampling process of particle state. And the effective validation and utilization of echo was accomplished by generalized probabilistic data association algorithm. The concrete steps of algorithm were given, and the theory analysis and simulation results showed its validity.关键词：maneuvering multiple target tracking;multiple model particle filter;interacting multiple model;generalized probabilistic data association
- 2843
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- 0
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- 4
发布时间：2023-11-14 - 摘要：Abstract:In order to solve the optimal coordination problem of directional relays in a complicated multi-loop power networks,a new model for directly obtaining MBPS（Minimum Break Point Set ）was established through the primary/backup relay’s coordination dependency relationships. Based on the ACO (Ant Colony Optimization) algorithm, a new algorithm was presented to solve the model. The formula of calculating the heuristic information was constructed to suit the MBPS problem.Compared to the available methods, the determination of the all directed loops of networks was completely avoided. More optimal solutions could be achieved at the same time after once algorithm calculation, and a smaller number of the iteration was required. The method was validated by the example.关键词：coordination and setting of relays;node adjacent matrix;ant colony optimization;minimum break point set
- 2891
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- 0
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- 2
发布时间：2023-11-14 - 摘要：Abstract:In V-BLAST systems, when channel estimation errors exist, the performance of conventional successive interference cancellation (SIC) detector based on minimum mean square error (MMSE) degrades obviously, meanwhile, computational complexity of these algorithms is still high. In order to overcome these problem, a novel adaptive hybrid SIC detector and the correspondingly optimal detection order were proposed based on the subspace tracking algorithm and Hermitian matrix perturbation theorem. The simulation results showed that the proposed algorithm is effective and has perfect immunity to the accuracy of channel estimation errors.关键词：signal detection;multiple-input multiple-output;successive interference cancellation;channel estimation;subspace tracking
- 3509
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- 8
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发布时间：2023-11-14 - 摘要：Abstract:Aiming at the problem that the optimum spatial temporal adaptive processing (STAP) took a great deal of sampling data and had very high computation complexity, a bi-iterative spatial-temporal adaptive processing (BI-STAP) for clutter suppression and moving target detection based on correlation matrix in airborne radar system was proposed. Firstly, each succeeding column and row of the received spatial temporal data matrix was stacked one beneath the other respectively, and the high-dimensional weight vector was written as the Kronecker product of the two low-dimensional weight vectors. Then by utilizing a bi-iterative algorithm two low-dimensional weight vectors can be solved on the basis of correlation matrix．Experimental results by using the measured data demonstrated the effectiveness of the proposed method. Theoretical analysis and computer simulation results illustrated that the proposed method can converge rapidly and decrease the computation complexity and sample requirement. In the presence of large random amplitude and phase errors in the array elements, the proposed method can achieve robust performance without large loss.关键词：airborne radar;STAP;clutter suppression;bi-iteration;complexity
- 2589
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- 10
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发布时间：2023-11-14 - 摘要：Abstract:In order to improve the performance of symbol detection in single-carrier frequency domain equalization (SC-FDE) system, a list-based detection method used in SC-FDE was proposed, and its performance was analyzed. The algorithm firstly extracted bit reliabilities of conventional SC-FDE symbols, then listed the symbols whose reliability were lower than the threshold, and compared all the likelihood of listed symbols. The symbol with maximum likelihood was set to be the final detection values. According to the choice of threshold, as well as the choice of window size, the algorithm could offer a flexible configuration between implementation complexity and performance. Simulation results showed that this method can achieve significantly improved performance in frequency selective fading channel.关键词：single carrier frequency domain equalization (SC-FDE);reliability;list-based detection
- 2401
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- 2
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发布时间：2023-11-14 - 摘要：Abstract:An optimal restoration sequence of generating sets based on fuzzy vector projection was presented to determine the thermal power generating units′starting-up sequence during early stages of power system restoration. The internal and external factors which influence the restoration sequence of the generator were discussed based on existing results. Taking into account the fact that many constraints in the language have greater fuzziness and the trapezoidal fuzzy numbers in L-R forms have good compose operation properties, the fuzzy mathematics method was used to deal with a variety of factors that affect the boot sequence units. The optimal restoration sequence of generator was obtained by fuzzy vector projection between decision-making index vector, ideal solution and negative ideal solution with normalized trapezoidal fuzzy numbers in L-R forms. The correctness and effectiveness were proven through the example of the calculation results.关键词：restoration;sequence of generator start-up;power system restoration;unit optimization;fuzzy decision
- 2374
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- 0
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发布时间：2023-11-14 - 摘要：Abstract:The physicochemical properties and mineral separation of a phosphate rock with siliceous and carbonates gangues were investigated. The results showed that this ore mainly contains flour-apatite, calcite and quartz. The partial substitution of (CO3)2- for (PO4)3-exists. There are Ca,P,O,Si and C elements on the rock surface,and their amounts are different from those in the bulk, especially the Si and C elements. The P2O5 content tends to firstly increase and then decrease with the reduction of ore particle size. However the contents of A.I and L.O.I show a trend of first decrease and then increase. This indicated that the phosphate and gangue minerals are upgraded in different size particles. For fine ore particles with low P2O5 content, a reverse flotation with cationic collector was employed to separate quartz. The P2O5 grade is increased by 4% and high P2O5 recovery with 80% are obtained. Owing to the existence of carbonates gangues, the acid or weak acid conditions are suitable for flotation.关键词：fluorapatite;physicochemical properties;mineral separation;Flotation
- 3342
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- 4
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发布时间：2023-11-14 - 摘要：Abstract: Fluidization experiment was carried out in a 368 mm×368 mm square fluidized bed with FCC particles to investigate the regime transition from bubbling to turbulent fluidization. The differential pressures at different axial locations were measured and the s standard deviation of pressure gradient fluctuations was used to determine the transition velocity, Uc, defined as the superficial gas velocity at which the standard deviation reaches its maximum. It was shown that, during the transition, the average behaviors of gas-solids fluidization in square fluidized bed are symmetric about the bed cross-section and non-uniformly distributed along the bed height, always with a dense particle-phase at the bed bottom. The Uc was found to be different at different axial locations. From the upper section of bed downwards to the lower, Uc increases linearly, indicating that the regime transition takes place first at the upper section of bed and then spreads downwards with increasing superficial gas velocity. Also, the static bed height has a noticeable effect on Uc and, corresponding to an increased static bed height, Uc becomes increased at all axial locations, simultaneously. The experimental results showed that the most predictive correlations reported in literatures obviously need to be improved.关键词：square fluidized bed;bubbling fluidization;turbulent fluidization;transition velocity;flow regime
- 2914
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- 2
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- 1
发布时间：2023-11-14 - 摘要：Abstract:The improvement of polycrystal diffraction structure of 7-ADCA was realized tby obtaining the X ray powder diffraction pattern within shorter time after carrying out improvement in probe, searching peaks automatically and indexing the pattern by Dicvol91, establishing the molecular model as a zwitterionic form, and refining the cell with more parameters. The results showed that compared to the previous work, the system, space group and unit cell parameters are nearly invariable, while the Rwp decreases from 14.95% to 7.78% because the fraction coordinate of each atom in the unit cell changes significantly. Finally, a better crystal structural model of 7-ADCA was obtained which can explain its growth characteristics reasonably.关键词：7-ADCA;crystal structure;X-ray powder;improvement
- 3756
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- 6
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发布时间：2023-11-14 - 摘要：Abstract:The calcium base bentonite was modified by aluminum and silver salts. By means of optimizing the Al or Ag loading, calcination temperature and calcination time, the modified bentonite with high performance of treating dye wastewater was obtained. The modified bentonite was characterized by XRD, SEM. FT-IR and N2 adsorption techniques. The results showed that polyhydroxy-aluminum entered into the interlayer of the modified bentonite and Si—O—Al bond was formed between the framework of bentonite ([Si4O10]n) and [Al3O4(OH)24(H2O)12]7+ in the modified bentonite. The interlayer spacing, surface area and pore volume were evidently improved by the modification. The modified bentonite was used to treat three types of dye wastewater with a concentration of 500 mg/L. The decolorization ratio for the dye wastewater was 90%-96 % and the ratio of COD elimination was 75%-90%.关键词：Bentonite;modification;characterization;dye wastewater;performance evaluation
- 3539
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- 0
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- 2
发布时间：2023-11-14 - 摘要：Abstract:Thermo-sensitive materials with different phase transition temperature were synthesized with methyl cellulose(MC), N-Isopropyl acrylamide(NIPAM), methacrylic acid(MAA) and Acrylic amide(AM). The kinetics of moisture absorption/release was studied using batch adsorption/desorption experiment. The thermal decomposition temperature and the structures of the samples were characterized using TG-DT and FTIR, respectively. And the effects of low critical solution temperature (LCST) of thermo-sensitive materials on the moisture absorption/release of humidity-controlling composite material were discussed. Results showed thatthe desorption rate of materials increased with the decrease of LCST of thermo-sensitive materials. The composition material with NIPAM and MC had the fastest rate of release moisture, more than 95% of adsorpted amounts desorpted in 10 minutes at 80 ℃.The organic-inorganic thermo-sensitive phase change material was prepared by MC and CaCl2, and it had a high capacity of moisture absorption of 1.45 g/g at RH（reletive humidity）= 100%, and all materials had good thermal stability under 300 ℃.关键词：thermo-sensitive material;humidity control;composite materials;water absorption
- 3283
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- 2
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发布时间：2023-11-14 - 摘要：Abstract:The developmental trend of EHV transmission tower is high strength tube tower. However, present research has been mainly focused on angle tower and domestic design codes do not contain design parameters of steel whose strength is higher than Q420. For this issue, pin-ended experiment of 20 different axially loaded high strength steel tubes was conducted, and the stability analysis of the tubes was done by means of FEA and related codes. The experiment and analysisshowed that Q420, GR65 and Q460 steel tubes have higher strength than corresponding values in domestic codes, and the trend becomes more and more obviousalong with the increase of steel yield strength. The propositional strength reduction formula covered the lower limit of FEA calculation and experimental values, and could be used as a reference for the corresponding designs.关键词：high strength steel tube;stability;experimental investigation;strength reduction;EHV transmission tower
- 3527
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- 3
发布时间：2023-11-14 - 摘要：Abstract:Hydroxyapatite/Chitosan (HAp/CS) bio-coatings were prepared by a novel hydrothermal electrophoretic deposition on CS modified carbon/carbon (C/C) composites in isopropyl alcohol, using sonochemical process resulted HAp nanoparticles as raw material. The influences of hydrothermal temperature on the phase, microstructures and the deposition kinetics of the coatings were investigated. The HAp/CS coatings were characterized by X-ray diffraction (XRD), transmission election microscopy (TEM), Fourier transform infrared (FTIR) spectrum and scanning electron microscope (SEM) analyses. Results showed that with the increase of hydrothermal temperature, the porous structure of the coatings changed from loose combination to close combination, and the cohesive force was enhanced. Kinetics investigations showed that the deposition rate also increased with the increase of hydrothermal temperature. The deposition activation energy of HAp/CS coatings by the hydrothermal electrophoresis deposition process was calculated to be 43.58 kJ/mol.关键词：hydrothermal electrophoresis deposition;hydrothermal temperature;hydroxyapatite;chitosan;carbon/carbon composites
- 2942
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发布时间：2023-11-14 - 摘要：Abstract:According to the manipulation space and kinematic characteristic requirements of surgery robot, a new hybrid robot structure with redundant 8-DOF was introduced. It was composed of SCARA(PRR) serial part and a 2-DOF parallel rotation mechanism. Mathematical models of forward and inverse solutions were established to resolve the anti-kinematic analytical solution problem and the kinematic equations was obtained. Meanwhile, the workspace cloud regional distribution was worked out by the Monte Carlo Method to derive its surgical operation workspace enveloped by random points. Theoretical analysis and simulation results proved that the robot possesses an better kinematic characteristics and can meet the request of practical operation workspace.关键词：surgical robot;hybrid structure;workspace;kinematic analysis
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- 5
发布时间：2023-11-14 - 摘要：Abstract:Based on the unified partition of all modules in product chain, the method of planning and implement of reconfiguration module was proposed. The property attribute of customer demand was reduced and the weight of property attribute was calculated based on rough set theory, by similarity degree was calculed, the similar module of products chain are clustered to common module and family module to accomplish reconfigurable module planning.common module,family module and their parts was parameterized,so these module can be used different products by reconfiguration. This method applies in the enterprise packaging machinery product design, has realized the product modules reconfigurable.关键词：rough set theory;modularized design;module cluster plan;reconfigurable;roll paper package machine
- 2565
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- 2
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- 0
发布时间：2023-11-14 - 摘要：Abstract:Aiming to the problems that design data is huge, the range of rational blast furnace profile is wide, and the limit is fuzzy, the method to generate the design primal scheme for blast furnace profile is proposed based on case-based reasoning approach. The character attributes of blast furnace profile and its hiberarchy are analyzed, and aiming to the problem that the right weigh is small and the searching efficiency is low relatively when the number of character attributes is big, the Nearest-Neighbor approach is improved by introducing a multilayer dynamic index tactic. The result shows that design scheme of blast furnace profile can be produced intelligently, the veracity and validity of the similar case retrieval can be enhanced, and the design scheme with high comparability and reference for latter design can be provided.关键词：Blast furnace profile design;Case-based reasoning;Nearest-Neighbor Approach;multilayer dynamic index
- 2642
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- 0
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- 3
发布时间：2023-11-14 - 摘要：Abstract: A new type of SM carbon coated optical fiber was tested using the concrete models of optical fiber crack sensing to get its mechanic optic constitutive relation and performance characteristics of concrete structural crack monitoring. The results indicated that the carbon coated optical fiber is able to monitor the development of the crack with high sensitivityof 0.02 mm and its dynamic range of 1～4.5 mm is larger significantly than the common SM optical fiber. Thereby it could offset the disadvantages of common SM optic-fibers for crack monitoring and be used in severe conditions.关键词：distributed optic-fiber crack monitoring;carbon coated optical fiber;optical fiber sensing model test;sensing sensitivity;dynamic range
- 2822
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- 0
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- 1
发布时间：2023-11-14 - 摘要：Abstract:The impact issues during dual-arm or multi-arm space manipulator capturing object was studied by extending the concept of "Generalized Straight-Arm Capture(GSAC)" to a dual-arm system. The configuration satisfied "GSAC" can reduce the effect of impact force, and guarantee the stability of system, then avoids the limit of joint velocity when control the compound. Finally, one unique strategy of capturing object was proposed, which accomplishes the capture and controls the attitude of base effectively.关键词：space manipulator;momentum conservation;manipulator configuration;base attitude
- 2661
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- 2
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- 1
发布时间：2023-11-14 - 摘要：Abstract:Based on the analysis of the transmission character and detecting principle of the ultrasonic wave, a ultrasonic test method of biomechanical equivalent artificial soft materials was put forward, and a measurement and analysis system of ultrasonic test for the mechanical properties of the artfical soft materials was designed. The wave speed, elastic modulus, attenuation of three types of biomechanical equivalent artificial soft materials with different density were tested and calculated. Based on the platform of Labwindows/CVI and MATLAB, the ultrasonic echo signalwas decomposed and analyzed in details with many methods. At last, the relationship between the mechanical properties of equivalent artificial soft materials and the ultrasonic echo signal was analyzed. The results indicated that the proposed method is correct and validated.关键词：artificial soft materials;ultrasonic test;mechanical and physical parameters;echo signal
- 2894
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- 4
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- 2
发布时间：2023-11-14
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