最新刊期
卷 40 ， 期 6 ， 2008
- 摘要：Abstract:Confluence River is a common occurrence in natural rivers, and the sediment transportation and pollutant dispersion strongly depend on the characteristics of flow structure in the confluence zone. Prior studies mainly focused on two dimensional properties of the separation zone, in which the variation of separation zone size from water surface to the bottom is often neglected. The experiments were performed in a flume, and the characteristics of separation zone were analyzed by the commonly used streamline and velocity isoline firstly proposed in this study. The velocity isoline method was conducted by the longitudinal velocity contour line for its big impact on flow structure. Based on the analysis of the selected data from prior experiments, the geometry and tendency of the separation zone may be changed with the variation of the different distance to the bottom and the discharge ratio between main and tributary rivers.关键词：confluence river;separation zone;streamline;isoline
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发布时间：2023-11-28 - 摘要：Abstract:It was very important that during cast in place cantilever segment construction of a concrete girder bridge the elevation of the traveling form had to be adjusted considering the deflection changes induced by solar temperature effects. In this paper, a practical computation method is presented to simulate instantaneous temperature effects of box girder bridges. Formula of instantaneous temperature and instantaneous relative humidity were proposed according to the observation results of Guanyinsha Bridge and the information of local weather condition. The instantaneous maximum temperature of the deck surface at daytime was determined using boundary conditions of heat flow equations. According to the observation, temperature of the deck surface varies along transverse direction with parabolic distribution, and vertical temperature gradients for the left web region and right web region were different. Therefore, for analysis of thermal stresses using the space beam model, the nodal forces were described separately by a double moment. The errors of deflection were about 6% using this method indicating that it may be applied to predict solar temperature effects of concrete bridges during construction.关键词：bridge engineering;single-cell box girder;solar radiation;temperature effect
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发布时间：2023-11-28 - 摘要：Abstract:According to two units with hydraulic coupling in hydropower plants, the effect of expanded unit connection to low frequency oscillation’s damping was studied in detail. With the mathematical model of hydraulic system which accurately reflectes each vibration mode of water flow, and the established mathematical model of expanded unit connection deduced from the five order integrative stability model of generator and the interface model between generator and electric power network, the whole state equations to describe the hydraulic、 mechanical and electrical system were derved, furthermore, the effect of expanded unit connection to low frequency oscillation’s damping and stability was analyzed with a given case. The results indicated that, for a system with two units having hydraulic coupling, low frequency oscillation’s damping was increased by the effect of expanded unit connection, and the effect to low frequency oscillation suppression was identical for larger increased damping on one unit and smaller increased damping on two units, while the hydraulic coupling had less effect to the distribution of damping.关键词：hydropower plant;low frequency oscillation;expanded unit connection;stability analysis
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发布时间：2023-11-28 - 摘要：Abstract:In order to explore mix design method of porous ecological concrete, the paper analyzed the strength and porosity of porous ecological concrete on the basic of orthogonal test method, through experimental study. The result showed that the observed porosity was on the rage of 13.8% to 31.5%, the average was about 25.24%, which was near to the target value. However, the observed compression strength was about 3.49 to 18.2MPa, the average was about 9.75MPa, which was just the theoretical values 9.21%to 48.02%.According to the test, when the porosity was over 20 percent, strength would be rapidly decreased .When the porosity was 31.5%, the strength was just 3.49MPa, which was far lower than the target value. The test also showed that the strength and porosity were also affected by ash set ratio. The bigger the ash set ratio, the higher compression strength, but the porosity would low. This could explain that the existed strength theory was not fit to the mix design of porous ecological concrete. According to the experimental results, it has established the empirical formula（4）and formula（5） about compressive strength and porosity design through regression analysis. The empirical formula can guide mix design of porous ecological concrete.关键词：Keywords: ecological concrete;porosity;compressive strength;mix design
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发布时间：2023-11-28 - 摘要：Abstract:In view of the uncertainty of indexes for evaluating water quality, in order to test the rationality of the criteria in evaluating water quality, resolve the incompatibility of the results of evaluating water quality indexes，and raise the distinguishment of the model of evaluating water quality，an effective and general model Projection Pursuit Classification model was proposed.The density window breadth R of the model was improved throretically, making the model more scientific and stable. Real Coding based on Accelerating Genetic was used Algorithm to find the best projective direction，and the datum of the best projective direction was used to research the level of the influence of each factor to water quality of the Yellow River.The classification results which accord with the fact were gained, providing the decision proof for protecting the water of the Yellow River reasonably.关键词：evaluating water quality;projection pursuit;Real Coding based on Accelerating Genetic Algorithm
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发布时间：2023-11-28 - 摘要：Abstract:The value of discrepancy coefficient i playes an important role in set pair analysis. The concept of fuzzy connection degree was applied to determine the value of discrepancy coefficient. As a result, more information can be utilized, and the results become more accurate and reasonable. This method was applied in comprehensive evaluation of regional groundwater resources carrying capacity. The evaluation results are in accordance with the results of other methods basically. This method is simply, feasible and reasonable, so it can be applied in different evaluation systems.关键词：carrying capacity of groundwater resources;comprehensive evaluation;set pair analysis;discrepancy coefficient;fuzzy connection degree
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发布时间：2023-11-28 - 摘要：Abstract:Variations of water and sediment of Jinsha River have important impact on incoming water and sediment condition of Three Gorges Reservoir. This paper analyzed the water and sediment characteristics upstream Ertan Reservoir. The method of multiple regression analysis was used to evaluate the sediment trap of the Ertan Reservoir. The siginficant analysis result showed that the regression models were all significant. The calculated results showed that during year 1998 to 2004, the annual sediment trap of Ertan Reservoir is about 5000～6500×104 t, and the Reservoir deposition rate is larger than 0.66％.From year 2001 to 2004, the sediment trap of Ertan Reservoir diminished to about 4000～5000×104 t due to the decrease of the incoming sediment upstream Ertan Reservoir. It is about 95%of the sediment coming from the upstream deposited in the Reservoir. Compared to year 1991 to 2000, the sediment trap in 2001 to 2004 is added about 0.238×108 t. It is contributed about 21.25% to the total sediment decrease of the Jinsha River basin. According to the way of Ertan Reservoir deposition and the current water and sediment condition, after the construction of the cascading reservoirs of Jinsha River and Yalong River, these reservoirs could trap about 90% of the incoming sediment, and the incoming sediment of Three Gorges Reservoir may decrease more than 60%.关键词：reservoir sedimentation;sediment trap;suspended sediment;Ertan Reservoir
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发布时间：2023-11-28 - 摘要：Abstract:Based on RNG model, the 3-D water and sediment model simulating the scouring funnel and water-sediment mixture flow in front of a reservoir dam was developed. Based on the flow characteristics in front of bottom orifice, the approach of water-depth and Zhang Ruijin formula were adopted to simulate the sediment carrying capacity near the riverbed. The results of model tests of movement of suspended sediment and of bed load were adopted to verify the developed model. Finally the model was applied to analyze the effect of water diversion and sand prevention of Shweli reservoir, Yunnan province and the results can assist in the decision of layout projection and reservoir management for the water diversion and sand prevention.关键词：scouring funnel;3-D water and sediment model;the approach of water-depth;bed load;longitudinal profile
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发布时间：2023-11-28 - 摘要：Abstract:n a small watershed of mountainous areas, it is difficult to calibrate roughness of slope surface, gully and stream, due to laking measured data of natural flow movement. As a result, when flash flood occurs, the flow pridiciton of slope surface, gully and streams disagrees with the acutal case. Based on the fractal theory and the projective covering method, this paper develped a method for measureing directly roughness coefficeint of overland flow, gully and stream flows. In order to verify the method, the bed roughness of mountain rivers was measured by means of 3-D Laser Scanner. Applying the measured data, the roughness of the river was determined using the method proposed in the paper.. It is shown that there is a good agreement with the computed and acutal values.关键词：overland flow;roughness degree;fractal;projective covering method;roughness measurement
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发布时间：2023-11-28 - 摘要：Abstract:The digital stream network and spatial information were extracted from raster based DEM data. The grid based hydrological and silty model was developed on the basis of excess infiltration mechanism, considering the impact of structural measures for soil conservation on runoff routing. The model was implemented for 11 floods from 1970 to 1989 in the Chabagou watershed of the Wuding River that is a tributary of the Yellow River. The “Nash%” of 10 floods were beyond 0.7 and all the relative errors of the simulated silt content were under 15%. The results show that the developed distributed model is suitable for the small watershed in the loess area.关键词：distributed model;hydrological and silty;Digital Elevation Model;Chabagou watershed
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发布时间：2023-11-28 - 摘要：Abstract:A FEM simulation model for twisting cold bend forming of boiler pipe was established. The three processes of pipe bend forming were simulated by the numbers in the round, including prepressing for deformation compensantion, twisting bending and deformation spring back of pipe after releasing mould. Many significant aspects for boiler pipe bending were analyzed, comprising the distributing characteristics of stress and plastic strain of pipe after bending; the effects of different forming parameters such as boost force and prepressing value on the cross section ellipticity and the ratio of wall thickness reduction of pipe after forming; the bending results comprising of several load cases in which the relative wall thickness of pipe model were different and the spring back law of pipe bending. It showes that: the bending stress of pipe mainly concentrated on initial portion of bending before spring back; there was an optimum value of the boost force that makes the bending quality of pipe optimal; the bigger the value of the relative wall thickness of pipe was, the better the bending forming of the pipe was; the spring back angle of pipe bending approximated 0.05rad, which was independent of the relative wall thickness of pipe.关键词：boiler pipe;bend forming;spring-back;FEM;numerical simulation
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发布时间：2023-11-28 - 摘要：Abstract:In vitro, a new method was used to measure corneal elastic modulus of an integrity rabbit cornea, and keratectomy protrusive displacement and stress changes were contrasted . In ex vivo to research biomechanical changes in the cornea of rabbits, excimer laser incision was performed in laser in situ keratomileusis. In the condition of hydrostatic pressure on the corneal inner surface, three corneas such as integrity, 1/3 ablation and 1/2 ablation in thickness and 6 mm diameter in central regions were scanned, and the protusive displacement in different corneal centers was calculated. Using Abaqus finite element software to establish the corresponding models, the rabbit corneal elastic modulus with accessed protrusive displacement were calculated. Calculated rabbit corneal elastic modulus increases with increased keratectomy volume. The tendency of the elastic modulus is consistent with the clinical detection. The more stress and the more displacement is in the model of the thinner central region.The displacement and stress are not rapidly changing in ablation border.关键词：corneal thinkness;protrusion;finite element analysis;elastic modulus
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发布时间：2023-11-28 - 摘要：Abstract: In this study a solution culture experiment was conducted to investigate the response of phytochelatins (PCs) in a floating aquatic plant Pistia stratiotes L. and a submerged one Elodea nuttallii exposed to a range of lower concentrations of cadmium (Cd) (0.01~0.64µmol/L). It was observed that two macrophytes showed obvious cumulative effects to lower concentrations of Cd exposure. PCs were significantly induced in P. stratiotes L. in a dose-dependent manner and increased with the increase of exogenous Cd concentrations. Cd concentrations at 0.08~0.64µmol/L were highly toxic to P. stratiotes L., accompanied by the dramatic production of PCs of plant tissues, especially in roots. Regressive analysis showed that there were linearly positive relationships between PC contents and Cd toxicity in E. nuttallii and P. stratiotes L.. It was indicated that PCs could be a promising biomarker for estimating Cd toxicity. Compared with E. nuttallii, PCs in roots of P. stratiotes L. was sensitive to Cd contamination and may be a sensitive indicator to reflect Cd toxicity in the aquatic ecosystem.关键词：Phytochelatins (PCs);Cadmium;Macrophytes;Pistia stratiotes L.;Elodea nuttallii
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发布时间：2023-11-28 - 摘要：Abstract:Abstract：The effect of the intumescent flame retardant system on ABS/PA6(80/20)alloys was studied．The system was compounded with APP for acid sources and PA6 in ABS/PA6 alloys for carbon sources. The effect of different synergistic charring agents on the flame retardancy of the ABS／PA6 alloys was investigated, including pentaerythritol caged phosphate (PEPA), thermoplastic phenolic resin (TPPFR), epoxy resin (E-44) and Zeolite 4A. The results show that PA6 has the good effect of charring, When the wt% of APP is 25% , the limiting oxygen index (LOI) value was found to be 30 and the UL-94 measure be class V-1. When the wt% of APP is 35% , the UL-94 measure were found to be class V-0. The ABS/PA6/APP has the better flame retardancy when a little of synergistic charring agents (PEPA, E-44 or Zeolite 4A) were be added to the compound . The expansion, uniform, dense carbon layer formed on the surface of the complex after burning was observed by scanning electron microscopy (SEM).
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发布时间：2023-11-28 - 摘要：Abstract:Abstract：Single-phase ZnGeP2 polycrystals were successfully synthesized by modified two-zone vapor-transporting method（MTVM）and mechanic oscillations technique, directly from high pure(6N) Zn, Ge, and red P elements according to the ZnGeP2 stoichiometry and 0.1~0.3% P-rich. The synthesis reaction was carried in a special quartz ampoule to prevent the ampoule exploding by controlling the temperature. With the presynthesized polycrystalline, the integral and gray-black ZnGeP2 single crystals with size of Φ15mm×25mm were obtained by modified Vertical Bridgman Method (VBM). As-grown crystals were characterized by X-ray diffraction and IR spectrophotometer. It was found that there were two spontaneous cleavage faces which were (112) and (101) orientations respectively. After annealed at 550~600℃ surrounded by the ZnGeP2 powder in vacuum, the infrared transmission of a ZGP wafer with size of 10×10×2mm3 is above 55% in the region of 2~12μm .关键词：ZnGeP2;single crystal growth;VBM;X-ray diffraction;infrared transmission
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发布时间：2023-11-28 - 摘要：Abstract:In order to further improve shape memory effect(SME) and process efficiency of a FeMnSiCrNiNbC alloy , the effects of different electropulsing treatment on microstructure and SME of the alloy were investigated in the paper. The results showed that the shape recovery ratio of specimen subjected to 10% tensile pre-deformation following electropulsing treatment at 300V and 1Hz for 11 times reached maximum 86.5%, 8.1% greater than that subjected to ageing at 800℃ for 15 minutes after 10% tensile pre-deformation. In addition, it was found by SEM and TEM analysis that NbC carbides induced by electropulsing treatment precipitated more quickly, and the amount of NbC was much more and the size of NbC particle was smaller. Therefore, its SME can be further improved and the process efficiency is higher.
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发布时间：2023-11-28 - 摘要：Abstract:The size of text and weight of elements in feature vectors may affect text classification rule. In order to improve the classification accuracy,new concepts of the weighted frequent items and a weighted frequent item set mining algorithm to highlight great weight items were proposed. A pre-processing method for feature vectors was proposed to eliminate ill effects of the size of text on generating classification rules. Experiments demonstrated utility and feasibility of the method.关键词：association rule;text classification;weighted frequent itemsets
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发布时间：2023-11-28 - 摘要：Abstract:In order to mining the first-order predicate logic rule effectivly, this paper proposes a novel first-order predicate logic rule mining algorithm PHVB algorithm based on Gene Expression Programming(GEP). The main contributions includes: Proposes a new formal concept of the first-order predicate logic rule; proposes two strategies, quantifier-free strategy and Variables Bounding strategy, which make it is easy to deal with the first-order predicate logic rule mining with GEP; proposes a novel first-order predicate rule mining algorithm PHVB algorithm. Extensive experiments demonstrate that the feasibility and the efficiency of PHVB is high.关键词：First Order Predicate Rule, Gene Expression Programming, Data Mining
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发布时间：2023-11-28 - 摘要：Abstract:For complex function mining, traditional gene expression programming (GEP) needs large number of evolutionary generations and may plunge into local optimum. To solve this problem, this paper presents a novel evolutionary algorithm based on multiple expression genes programming (MEGP). The main contributions include: (a) provide a novel gene hierarchical representation model to encode solutions of complex function finding; (b) propose a chromosome architecture that allows of a genome with multiple candidate expressions; (c) theoretically analyze and compare the expression space of MEGP algorithm with traditional GEP; (d) implement the MEGP algorithm and the chromosome fitness evaluation algorithm. Extensive experiments show that the success rate of MEPG is 2-4 times of traditional GEP.关键词：gene expression programming;Multi Expression;Function Finding;Genetic Algorithm
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发布时间：2023-11-28 - 摘要：Abstract: In view of such drawbacks of current bionics optimization algorithms as poor local search ability and premature convergence , a competition model of forest dynamical evolution was established by using two principles . One was the contradictory unity of growth and whiting based on natural trees, and another was the competitive exclusion in forest ecosystem . Furthermore , a forest competition algorithm was proposed. To verify the algorithm , we applied it to solve transcendental equations . Compared with the Standard Genetic Algorithm , it ran faster . Compared with the Standard Particle Swarm Optimization , it had higher success rate in searching all solutions. This algorithm may provide a novel method for design and calculation of optimization.关键词：natural tree;forest;growth;competition;transcendental equation
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发布时间：2023-11-28 - 摘要：Abstract:The necessary and sufficient condition for a class of inequalities with radical functions like g=m1u1+m2u2+…+mnun was discussed based on the rationalization of radical functions. This condition successfully transformed the inequality with radical functions into a set of rational inequalities. Furthermore, the condition was applied to symbolic algorithm of global optimization of the class of radical functions. Thus, the former universal algorithm was improved so that the new algorithm is much more efficient.关键词：global optimization;symbolic algorithm;radical functions;sds
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发布时间：2023-11-28 - 摘要：Abstract:To detect forward obstacles for intelligent vehicle in complex taffic scenes, a novel obstacle detection method based on wavelet transform module maximum (WTMM) and support vector machine (SVM) was presented, considering obvious rear visual features of forward obstacles. Firstly, the candidate regions of obstacle (ROIs) were detected based on multi-scale singularity analysis with WTMM and multi-features combination of obstacle knowledge. Then, these ROIs were recognised based on a compatible binary tree support vector machine (BT-SVM) classifier for obstacle pattern of traffic scenes. Applied the proposed method to different traffic scenes (e.g., simply structured highway, complex urban street), the online experiment results show the efficient, real-time and universale ability.关键词：Intelligent vehicle;Obstacle detection;Wavelet transform module maximum;SVM;Complex traffic scenes
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发布时间：2023-11-28 - 摘要：Abstract:In order to enrich further the integrity verification mechanism in trusted computing,a model of integrity measurement was presented based on the idea of transitive trust in the TCG’s criterion.In the model, the execute right of an object was defined and specified strictly, and the integrity of the object was measured before execution.The model can prohibit malicious code from compromising the integrity of system and transit trust form one entity to next one, so that the chain of trust can be extended form the BIOS all the way to application layer .The model extended the security attribute of the present security model.关键词：trusted computing;transitive trust;integrity measurement
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发布时间：2023-11-28 - 摘要：Abstract:To solve Multiple Depot Vehicle Routing Problem (MDVRP) directly, ant’s transfer policy and method to construct valid solution were designed. When an ant began transfer, a temporary depot was prearranged to the ant, then the permanent depot was rooted when a depot was met with. After paths were constructed, several ants’ paths were selected randomly with the restriction of vehicles satisfied, and iterative depots were deleted and absent depots were inserted based on the regulars of “least decrease”，“least increase” and “nearest insertion”.Thus a solution of MDVRP was constructed. In order to improved algorithm’s performance, K neighbor was used to confine ants’ transfer objects, and ants’ paths and solutions were optimized by 2 Opt,and pheromone update policy was designed. The algorithm was tested on two standard data sets, and the results showed that the algorithm is an efficient one to solve MDVRP.关键词：Multiple Depot Vehicle Routing Problem(MDVRP);hybrid ant colony algorithm;2-Opt;valid solution construction
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发布时间：2023-11-28 - 摘要：Abstract:In order to economize the energy and reduce the loss of the oil field power network, based on the characteristics of oil field power distribution network，the power loss value was calculated. By adding compensation capacitor and adjusting tap position of on load tap changer, mathematical models for reactive power optimization were given,and by the method of dispersed compensation and centralized compensation, the optical position, capacity of compensation and the tap position of on load tap changer were studied.The reactive power optimization software of oil field power distribution network was programmed. Calculation examples of TAHE oil field power distribution network showed that the genetic algorithm can be used to determine the tap position and is more suitable to the compensation capacity and the energy loss than the dispersed compensation method.The dispersed compensation method can be used to calculate the compensation capacitor position.关键词：oil field power system;economy energy and low losses;Genetic algorithm;dispersed compensation
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发布时间：2023-11-28 - 摘要：Abstract:he existing machine vision systems sample images at a fixed resolution and a presetting speed in an inspection. In detection of small defects in a large background, there is usually a large amount of redundancy in the image data. Based on the development of low cost CMOS cameras and IEEE1394 data transmission technology, a machine vision system with an irregular imaging function is presented in the paper, including the irregular images’ data format, its mosaicing algorithm and memory distribution method of the image data. The system can irregularly sample images with a high resolution in the defect area and a low resolution in the background area, which reduces the total data in image processing and increases the precision and speed of the inspection significantly.关键词：machine vision system;irregular image;multi-resolution;visual attention
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发布时间：2023-11-28 - 摘要：Abstract:Due to the objective restrictions and impact, the reliability test data for heavy engineering machinery and equipment are in small samples and poor information. Therefore, there are differences between the results of reliability analysis and actual ones. To make the differences less, we put forward the possibilistic reliability method based on unascertained theory. The method were consisted of three phages which the critical elements selected by the optimality criteria method, limit state equations of main failure modes made by using incremental load method and the mathematical value of load distribution characteristics acquired by unascertained theory. The possibility of a bridge crane was calculated by the possibilistic reliability method. The results showed that the reliability of the structure can be increased by the method.
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发布时间：2023-11-28 - 摘要：Abstract:Based on the process of cooperation product design, the representation form of knowledge has characters of complexity,diversity and uncertainty. Analyzing the concept of pattern language, applying of information theory and fuzzy comprehensive evaluation method,a saved table structure is proposed for design knowledge description method and knowledge description based on pattern language, a model is founded for knowledge discovery and knowledge fuzzy comprehensive evaluation based on pattern language. Examples of the design of blanking die, the feasible and practical of basing on pattern language design knowledge description and save method is validated.
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发布时间：2023-11-28 - 摘要：Abstract: evolvement of plate in ifteen_roller combination leveler are studied in this paper using both analytic geometry and FEM . The results show that the bending deformation and curvature evolvement are different from those obtained by general leveler. The technologies of parallel leveling and tension leveling are adaptive to the roll system of combination leveler, which not only can improve leveling precision, but also can erase the influence of negative torque on leveling roll, thus improving the leveling strength capacity of leveling materials. Meanwhile, a new calculating method of leveling process was pointed out, whose results were basically consistent to those of experimental results.关键词：plate steel;Leveling model;combination
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发布时间：2023-11-28 - 摘要：Abstract: A new airborne pattern mass flowmeter is presented, It’s theoretical model and practical system structure are given. The mass flowmeter consists of a driver and inductive wheels of mass. The driver provides energy for running of component in the interior of flowmeter, and flux of oil is measured by the inductive wheel of mass,this is difference between the mass flowmeter and other mass flowmeter. The Two signals from the mass flowmeter is filtered by no change of phase, and the phase difference is given by zero passage arithmetic. The relation between mass flowmeter and phase difference is validated. the experiment demonstrates that the mass flowmeter is higher Accuracy, is good at anti-vibration, anti-tilt, bearing greater acceleration and less power consumption.关键词：mass flowmeter;driver;inductive wheel of mass;zero passage arithmetic;phase difference measurement
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发布时间：2023-11-28 - 摘要：Abstract:The aviation igniter spark energy is an important parameter to the reliable firing, conveying and combustion. This system use “oscillograph test method” to measure the discharge current and voltage simultaneously and efficiency without affecting the system’s working condition. In the course of practical test, the value is distorted resulting from the EMI (the transient voltage 3～4KV,current 13KA) which generated by the ignition system. Through the research from the source of interference, the interference path, the interfered equipment three aspects and practice of the EMC of the system, proposed a series of effective measures to improve the EMC ability of the system. The research is worthwhile to resolve the system’s EMC ability which is under powerfull electromagnetic interference.关键词：aviation igniter;ignition energy;automatic measurement system;EMC;grounding;shielding;research and practice
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发布时间：2023-11-28 - 摘要：Abstract: A mathematical model was established to study the brake characteristic of pneumatic disc brake based on the quality-alterable air’s thermodynamics and dynamic law. Based on the model, the braking were processes simulated by AMESim and learnt by experimentations. The result indicated that the model was accurate to reflect the braking pressure. After the braking pressure passing the flex point at the end of abruptly jump, it will increase slowly to goal. The responding time of pressure stroke and exhaust stroke are about 0.5s and 0.3s respectively. The pneumatic disc brake could meet the requirements of drill speed and bit weight fine regulation by rational control strategy. The model can also provide a valid theoretical basis for design and technical transformation of the pneumatic disc brake.关键词：pneumatic disc brake（PDB）;brake characteristic;mathematical model;AMESim;oil rig
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发布时间：2023-11-28
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