最新刊期
卷 45 ， 期 1 ， 2013
- 摘要：Abstract:Based on soil samples from living debris flows in Jiangjia Gully and deposits of debris flows in various valleys and regions in China, a general form of grain size distribution,P(D) =CD^-μexp(-D/Dc),which fitted the soils of debris flows perfectly and universally was proposed.The values of μ and Dc were used to describe the nature of grain composition,where the power exponent represents some characteristic porosity of the soilin natural condition, and Dcdefines a characteristic scale for the range of grains.According to soil samples of debris flow from various sources,μ is less than 0.1,and for high density debris flow,μ is less than 0.05.The bulk density of debris flow increases with Dcin a power law. So the parameter Dc can depict the power of the transportation of debris flow. Finally, the parameters were used to evaluate the debris flows occurred in the Wenchuan earthquake area, which agrees well with the observations in Jiangjia Gully.关键词：debris flow;grain distribution curve;scaling distribution;distribution parameters;debris flow evaluation
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发布时间：2023-11-14 - 摘要：Abstract:For the prevention and control of engineering design, the magnitude of debris flow impact force is a very important parameter and is difficult to be estimated and measured in the field. To reduce the influence of model scale, debris flow impact force experiment was carried out by large flume and the wavelet analysis was used to de-noise the debris flow impact signal. The results showed that the de-noised debris flow impact signal could be impact pressure of liquid phase slurry by comparing the reconstructed signal with de-noised signal. The analysis of debris flow impact pressure experiment data showed that the coefficient approaches 0.5 in the debris flow impact pressure formula p=Kρfv^2.关键词：debris flow;impact pressure;wavelet analysis;signal de-noising
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发布时间：2023-11-14 - 摘要：Abstract:The Wenchuan earthquake has induced a great mass of collapse and landslide in the Longmen Mountain area,leading to the occurrence of extra-large scale debris flows.Through analyzing the failure reasons of two typical debris flow prevention engineerings,the main reason was that the stone masonry structure,which has been widely applied currently,has weak availability of resistance from debris flow.In order to resist the damaging of extra-large scale debris flows,new engineering structures were proposed for preventing debris flow,such as combination of check dam and drainage canal.The details of these new structures were check dam with the type of reinforced concrete frame + stone masonry dam body and prefabricated reinforced concrete cube boxes,drainage canal with the type of compound section and prefabricated reinforced concrete cube boxes.These new structures can improve the resistant abilities of check dams,decrease construction cycle,protect eco-environment of drainage area and make full use of existing materials in the gully without increasing investment.This new technology proposed can effectively control the extra-large scale debris flow in the Longmen Mountain area.关键词：Wenchuan earthquake;extra-large scale debris flow;control work
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发布时间：2023-11-14 - 摘要：Abstract:The rainfall forecast in mountainous region generally has high uncertainty,and the measurement and real-time transfer of actual rainfall data is difficult and expensive.Based on information technologies,including smartphones and cloud computing,the framework of an interactive flood warning system was proposed and tested for ungauged mountainous regions according to the mass prediction and prevention principle.Firstly,geographic coordinates and rainfall estimate inputs from local residents were collected via smartphone terminal.Then the parallel hydrological model on the cloud server was automatically executed to simulate the rainfall-runoff process. Finally,according to the allowed flood discharge at different locations,warning levels were derived from runoff simulation results and pushed to the rainfall information provider and potential flood sufferers via smartphones.Because of the high efficiency of data collection and hydrological simulation,residents can receive warning information before the flood arrives,and save time to escape.The application of this system would essentially improve the technical level of mass prediction and prevention.关键词：flood warning;smartphone;ungauged basin;digital watershed model;mass prediction and prevention
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发布时间：2023-11-14 - 摘要：Abstract:Debris flow is generally composed of a wide range of solid particles and viscous pore fluid. Interactions between solid particles and the resulted segregation in debris flows are affected by multiple parameters,and usually govern the rheological properties of debris flows and the flow mobility.Through the theoretical analysis,the effect of solids segregation on the flow mobility was demonstrated.Furthermore,granular debris flows with grains of mixed sizes were numerically modelled and the contact behaviour of solid particles was fundamentally studied using the Discrete Element Method (DEM).Compared to granular flows with uniform solid particles,the mechanisms of solids segregation and the effect on granular flow mobility were investigated.The results showed that that segregation can significantly increase the flow velocity of the front head and the length of the granular body on slopes.Due to the solids segregation,the shear rate developed in the granular body is greatly enhanced and no shearing-enhanced boundary layers near the sloping bed can be observed.关键词：debris flow;segregation;theoretical analysis;discrete element method
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发布时间：2023-11-14 - 摘要：Abstract:The bent-type aqueduct structure is prone to injury under strong earthquakes, and the structure’s overall anti-seismic performance changes. Based on the concrete plastic damage constitutive model, the equivalent spring model was applied to stimulate the SSI while a temperature drop process was applied to stimulate the effect of pre-stressed steel bars in the aqueduct. In addition, the overall anti-seismic performance of bent-type aqueduct structure was studied through analyzing the dynamic response law and damage development process of a large bent-type U-shaped aqueduct under strong earthquakes by applying time-domain analysis. The research results indicated that under strong earthquakes, the bent frame joints are the anti-seismic weak parts of aqueduct, while overall damage of groove body is less likely. For bent-type aqueduct structures which are located in areas with high seismic intensity, main attention should be paid to the anti-seismic safety of the lower part of the support structure.关键词：aqueduct;damage;concrete damaged plasticity model;failure model;bent
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发布时间：2023-11-14 - 摘要：Abstract:In order to improve the seismic capacity of the aerated concrete infill walls, the mechanical properties of aerated concrete block and low cyclic horizontal force experiment of aerated concrete infill walls were studied. The bearing capacity and deformation ability of aerated concrete filling wall were investigated through the vertical connection of steel bar between the frame beam and aerated concrete block. The results showed that the cracking load of the aerated concrete block is about 80% of its compression failure load, and the aerated concrete block can withstand a certain pressure and ductility after compression cracking. When the aerated concrete block is bended and tensile，its brittle fracture characteristic is showed. When aerated concrete infill walls and beams are connected by mortar, the mortar layer is failure by shear, filling the wall cracking along the horizontal mortar joint. When the filling walls and beams are connected with the vertical steel bar, the yield strength and ductility of the filling walls are obviously improved owing to steel bar and mortar, thus the aerated concrete is cracked by the bar pulling.关键词：aerated concrete;filling wall;frame structure;horizontal load
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发布时间：2023-11-14 - 摘要：Abstract:The cross section arrangement of shape steel in transfer columns of SRC-RC hybrid structure was analyzed based on low cyclic reversed loading test of 16 specimens. The results showed that area ratio of shape steel has serious effect on seismic behavior of transfer columns. Displacement ductility decreases along with the increment of shape steel arrangement, but carry capacity increases at the same time. Partially existed shape steel makes the aberrance of internal stress and hence leads serious shear effect to transfer columns, so deformation ability and postpeak behavior degenerate when area ratio of shape steel promotes. Shape steel not only makes the flexural stiffness of cross section advanced but also postpones the appearance of cracks, and hence increases elastic lateral stiffness of specimens, but lateral stiffness at yielding point has little effect by shape steel arrangement. Through test and theoretical calculation, maximum of bending capacity in rational range of shape steel arrangement was confirmed which can be used to prohibit serious shear effect and insure deformation ability against brittle failure. Test data and the analysis results could provide references to seismic design and construction of hybrid structure.关键词：steel reinforced concrete（SRC）;seismic performance;stiffness;ductility
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发布时间：2023-11-14 - 摘要：Abstract:In order to efficiently sample the suspended sediment with a low concentration,a three-dimensional simulation design was presented for a new suspended sediment sampler characteristic of a hydrocyclone.Using a Lagrangian approach with fluid multi-phase model,the pressure distribution,fluent flow,and particle trajectory in the inner sampler were three-dimensionally simulated.A laboratory experiment showed that its sediment separation efficiency is up to 85% for the sediment particles with individual grain size of 63 μm,which achieved the rapid in-situ collection of suspended sediment,and the predictions using the three-dimensional simulation are in good agreements with experimental results.关键词：suspended sediment;sediment sampler;hydrocyclone;three-dimensional numerical simulation
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发布时间：2023-11-14 - 摘要：Abstract:The local landform will be changed after reclamation through sea-dike building.It will affect the character of tide and tidal current,and the sediment transporting near the reclamation region.Taking the shore reclamation between Oujiang and Feiyunjiang Estuary as example,a tidal current mathematical model was used to study the effects of the hydro-dynamic environment due to the large-scale reclamation.Based on triangle grid and finite volume method,the flow model was examined by observed tidal level stations and synchronous vertical lines.Tthe comparison between computed result and measured solution showed very good agreement.After the project building,the high tide level reduced to some extent and the flow of front reclamation line reduced by a big margin.But it had a little influence on the core ports of Wenzhou.And the tidal influx through Feiyunjiang Estuary kept decreasing.The result can be used as a reference and inspiration for the effects of the large-scale reclamation projects on hydro-dynamic environment.关键词：tidal estuary;reclamation project;hydro-dynamic;mathematical model
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发布时间：2023-11-14 - 摘要：Abstract:By applying flow rule of micro compression rigid plastic material, a three dimensional calculation model based on radial basis points interpolation RPIM of skew extension rolling process was established.The radial basis function has Delta function properties so that the essential boundary conditions can be applied directly．The polynomial functions can be accurately reproduced and has higher precision through adding polynomial functions to the radical basics function(RBF), hence it is suitable for metal plastic forming process simulation．Singularities in velocity discontinuity are eliminated using the method of node encryption in biting place，and applying searching method to search field nodes so as to eliminate or ease the impact of uneven distribution nodes．Finally，volume locking phenomenon can be eliminated by reduced integral in rotary extension process. The comparison of calculation results with results of finite element method simulation and experiment verified the feasibility and effectiveness of skew extension rolling process simulation by RPIM．关键词：skew extension rolling;radial point interpolation method(RPIM);rigid plastic;volume locking;flow law;meshless
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发布时间：2023-11-14 - 摘要：Abstract:The axial compression member test was conducted to investigate the stability performance of these members, including nineteen Q420 L220×20 specimens which slenderness ratio(λ) ranged from 30～90. The test results showed that when slenderness is λ>45,flexural buckling was observed and when slenderness is λ≤45,local or flexural-torsion or torsion buckling was observed. The applicability of local buckling wide thickness ratio formula and flexural-torsional buckling conversion slenderness ratio formula was researched. By means of inverse calculation segment length method, the column curve of the large size equal angle was got. The comparison with common size angle and parameter analysis was made. Calculation method of bearing capacity of large size equal angle was given. Two ends eccentric compression column curve was also researched, and a suggestion formula of slenderness ratio correction coefficient was given.关键词：high strength large size equal angles steels;axially loaded compression tests;inverse calculation segment length method;column curves
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发布时间：2023-11-14 - 摘要：Abstract:Ecological base flow (EBF) is a minimum channel flow to maintain a healthy river system and to avoid deteriorating its functions. A case study was conducted in the Yuanhe River which belongs to the Ganjiang River,a branch river of the Yangtze River.In this study,a distributed hydrological model of SWAT was adopted to simulate runoffs and base flows based on daily precipitations and designed scenarios of rainfalls. According to the concept of EBF and the content of base flows,the EBF at the important ecological function zones of the middle to the upper stream of the Yuanhe River was analyzed. Results showed that the EBF at the Luxi and Maozhou hydrological stations is 1.25 m3/s and 17.0 m^3/s,respectively,accounting for 11.14% and 17.39% of their averaged annual flows, respectively.These results are close to the results calculated by other methods.In addition,EBFs based on a distributed hydrological model of SWAT have the mechanism of water cycle and should be more reasonable than the values determined by other methods.关键词：ecological base flow;ecological water demands;distributed hydrological model of SWAT;scenario design;Yuan River basin
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发布时间：2023-11-14 - 摘要：Abstract:The FAO-56 Penman-Monteith method was used to calculate the potential evapotranspiration (ET0) from 1960 to 2010 in 45 stations in Sichuan.Then the cloud model was firstly applied to analyze the temporal-spatial variation characteristics of ET0.Results showed that from 1960 to 2010,ET0has firstly decreased then increased after 2000.The temporal distribution of ET0 is dispersive in the four areas.The dispersion in Sichuan basin, mountainous areas around basin and southwestern mountain area is more stable than that in northwest plateau.The spatial distribution of ET0is more dispersive and unstable than the temporal distribution.The mean annual ET0in southwestern mountain area is highest, followed by northwest plateau,Sichuan basin and mountainous areas around basin.The spatial dispersion of ET0 has firstly enhanced,then weakened after 2000.The spatial dispersion of ET0from 1991 to 2010 is less stable than that from 1960 to 1990,but the stability has been enhanced after 2000.关键词：FAO-56 Penman-Monteith;Sichuan;ET0;cloud model;temporal-spatial distribution
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发布时间：2023-11-14 - 摘要：Abstract:By establishing the real-time dynamic mapping relationship between the set of the actual construction state and the set of the emulation mode of the three dimensional and full scale numerical model, with numerical simulation technology as the main means, and combining with parallel computing method, the function of coupling real-time simulation of structure safety and schedule during the full process of construction was realized. The bad geological conditions were mapped to the numerical model, then according to the real-time simulation results, the prediction and evaluation of the structure safety with bad geological conditions were made, treatment measures were put forward if the safety of construction state does not meet requirements, and the treatment effect was predicted by real-time numerical simulation. The determined treatment measures were converted to construction parameters to feedback to construction schedule control system, and the influence on the construction schedule caused by treatment measures was evaluated simultaneously. Finally, based on a mixed programming technology with Python and VB.net, a large-scale underground cavern group construction structure safety and schedule coupling real-time simulation system was developed. The system realized the field office integration of underground cavern group construction safety and schedule control, which provides great technical support to safety and schedule control of underground cavern group construction.关键词：underground cavern group;real-time simulation;structural safety;schedule control;dynamic mapping
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发布时间：2023-11-14 - 摘要：Abstract:The non-linearity of unsaturated flow requests small time step and fine grid in the corresponding simulation,and the simulation often suffers from some unfavorable boundary conditions.Therefore,it is time-consuming to simulate the regional unsaturated-saturated flow by traditional numerical methods.In view of this issue,a 1D unsaturated model based on improved integrated Richards’equation coupled with 3D saturated flow model was proposed for the simulation of regional groundwater flow.The soil moisture was taken as primary variable in vadose zone. By separating the effect on soil moisture variation from pressure head and soil parameters, an improved integrated Richards’ equation model was presented to calculate the unsaturated flow in heterogeneous soil.A 3D groundwater model was established with control volume finite element method.These two models were coupled by their mutual nodes.The comparisons between results from the proposed model and Hydrus showed good agreement. Moreover, the proposed model takes the advantage of integrated Richards’ equation,thus it is more efficient to simulate large-scale flow problem with atmospheric boundary.关键词：groundwater;soil moisture;coupled model;integrated Richards equation(IRE)
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发布时间：2023-11-14 - 摘要：Abstract:In order to update the attribute reduction of decision table dynamically, the definitions of the simplified decision table and attribute reduction based on simplified discernibility matrix were proposed. It was proved that attribute reduction acquired from the definition is equivalence to attribute reduction based on positive region. Then the different cases of added object were analyzed, and incremental attribute reduction was mapped to the simplifying decision table to achieve. Finally, the attribute reduction algorithm based on simplified discernibility matrix was designed and the algorithm was further improved. The example and experiment results showed that the algorithms are effective and effieient.关键词：rough set;attribute reduction;discernibility set;discernibility matrix;incremental algorithm
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发布时间：2023-11-14 - 摘要：Abstract:Based on Zhang’s security model, an improved pairing-free certificateless key agreement,CL-AKA random oracle model, was proposed. An ephemeral-secret query and three types of fresh oracles were further defined in the improved CL-AKA random oracle model to achieve the simulation of key-compromise impersonation, disclosure of ephemeral secrets and perfect forward secrecy. A CL-AKA protocol with strong security was proposed, costing only 9 scalar multiplications on the elliptic curve. The secure of the new protocol was proved in the improved model. The comparative analysis pointed out that the new protocol with strong security and low computing costs can be used to build secure mobile communication environment.关键词：certificateless cryptography;authenticated key agreement;computational diffie-hellman assumption;standard model;public key replacement
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发布时间：2023-11-14 - 摘要：Abstract:To solve the issue that it is difficult to monitor the content on the KAD network because of occult of KAD message, a novel monitoring approach was proposed to obtain the content by intercepting the interactive message for a specified node on the network. First of all, the HashID for a keyword in the message of a supervised node was extracted by using ID mapping method. Secondly, a lightweight method of reverse conversion algorithm was adopted to obtain the corresponding value for a specified HashID, which can further judge the threat level for the node. Finally, the experiment was deployed on the KAD network constructed by eMule system. When ten nodes in 0X10 zone were selected as targets, the above approach was adopted to intercept the quest and publish massages that send to supervised nodes, and the semantic content for messages is obtained successfully. The result of the experiment demonstrated the necessity for network supervision, as well as the feasibility of the approach.关键词：KAD;content supervision;keyword ID;reverse conversion
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发布时间：2023-11-14 - 摘要：Abstract:In order to promote the convergence of immune clonal algorithm,based on the coordination of the exploration and exploitation,a new coevoluationary immune memory clonal algorithm was proposed. The whole population was divided into two population named as immune clonal population, which has two sub-populations, and immune memory population.The competitive coevoluationary operation was incorporated in the sub-population of immune clonal population to dynamic update the scale of population, and the fitness sharing, dynamic mutation mechanism and concentration regulation mechanism based clonal reproduction were also incorporated in the sub-population of immune clonal population to increase the diversity of the population. The immune memory population was optimized using the chaotic accurate search and elitist crossover in order to enhance the exploitation ability. Simulation results of benchmark functions showed that the proposed algorithm performs well and can get better results.关键词：immune clonal;immune memory;exploration;exploitation;coevoluationary
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发布时间：2023-11-14 - 摘要：Abstract:To solve the particle weights degradation and sample impoverishment problems in particle filter which was used in non-Gaussian nonlinear systems, a new kind of particle filter was proposed. The sampling particles could move to high likelihood area by using particle swarm optimization idea, and the weights of degradation of the particles were reduced. Then through the variation operation of the artificial immune, the range of the optimal value was expanded when searching for the optimization, and the diversity of the particles was increased, Simulation results showed that the state estimation accuracy of new algorithm is improved nearly 40 times than standard particle filter. The filtering efficiency is 37.523%, 37 times of the standard particle filter. This algorithm has better real-time and state estimation precision, and could effectively relieve the particle of the weights of the exhaustion of sample degradation.关键词：particle swarm optimization;artificial immune;particle filter
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发布时间：2023-11-14 - 摘要：Abstract:In order to improve the detection performance of cooperative spectrum sensing for cognitive radio (CR), the weighed cooperative sensing algorithm was investigated, by optimizing two sensing parameters including weight and observed time.The minimal false alarm probability was obtained by choosing the optimal weight under the given detection probability, while the optimal observed time was obtained through the proposed half searching. Simulations showed that compared to the traditional un-weighed cooperative sensing, the proposed algorithm could achieve lower false alarm probability and higher spectrum utilization, while the half searching could achieve lower computational complexity than the exhaustive searching. The results indicated that the proposed algorithm might make CR achieve the maximal spectrum utilization within the interference limit of licensed user.关键词：cognitive radio;signal detection;weighing;convex optimization;statistics
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发布时间：2023-11-14 - 摘要：Abstract:The traditional binary frequency shift keying (2FSK) technology cannot adapt to the attenuation characteristic of low-voltage power line carrier (LPLC) channel.In order to solve this problem, by using discrete short time Fourier transform and high-order moments theory,a novel signal-to-noise estimation algorithm,which can be used in time-frequency analysis,was proposed. Based on it,a multi-carrier binary frequency shift keying technique based on time-frequency analysis was implemented.Simulation results showed that the precision of the SNR estimation could meet the need of the LPLC communication system in practice and the multi-carrier system gains lower error rate than the single-carrier system while they are interfered by the same noise.关键词：frequency shift keying;discrete short time Fourier transform;power line carrier communication;signal-to-noise ratio estimation;high-order moments
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发布时间：2023-11-14 - 摘要：Abstract:A fast calibration was proposed, in which two gauge blocks were used to replace the standard plane controlled by the mechanical shifting device in the traditional calibration, and fewer datum points were sampled from the surface of the gauge blocks to calibrate the system. With this method, both system calibration and phase measurement can be implemented simultaneously. The real height of the object relative to the supporting plane can be obtained when the supporting plane was not superposed on the reference. A cuboid block of normal height of 14.00 mm was successfully measured by this method. Its mean relative error was no more than 1.35% and the root-mean-square error was less than 0.15 mm. The calibration was simplified and became more flexible with the proposed method.关键词：phase measuring profilometry;phase-to-height mapping;system calibration;three-dimensional shape measurement;fast
- 2751
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- 3
发布时间：2023-11-14 - 摘要：Abstract:Based on false nearest neighbors and unscented kalman filter (FNN-UKF), a dynamic prediction method for alumina concentration was proposed. In the new KPCA feature subspace, it was inspired by FNN that interpretation of alumina concentration would be estimated by calculating the variables mapping distance in the KPCA space to select secondary variables. Selected variables were introduced into BP neural networks as input vector. UKF algorithm, in which estimated value and variance matrix of state were updated to improve the generalization capability of the networks, was used to train weight values and threshold values. By using 247 samples of 160KA operating aluminum cell from a factory, experimental results demonstrated that the forecast error of 228 samples was ±1%, the computation was decreased to 52.07%.The method in which the computation time was reduced effectively can surely accuracy of parameter estimation.关键词：false nearest neighbors;kernel principal components analysis;prediction;alumina concentration;neural networks
- 2314
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发布时间：2023-11-14 - 摘要：Abstract:Scaled boundary finite element method (SBFEM) was applied to solve the boundary value problems of the electrostatic field in coaxial-cable, i.e., ring-type domain. To avoid the singularity in eigenvalue method, Schur decomposition was employed to update the original method. With scaled boundary coordinate transformation, the governing Laplace equation was semi-discretized to set of a second-order ordinary differential equations (ODEs) by the weighted residual approach. Introducing auxiliary variables, the rank of ODEs was reduced to one, and the general solution of electric potential was obtained by Schur decomposition. Integral constants were determined by the boundary conditions. Numerical examples, including coaxial-cable with various types of cross-section, were calculated and the result showed that singularity is terminated by the proposed approach in respect to Schur decomposition.Wide adaptability, excellent results and less amount of computation consumption are reached beyond other methods.关键词：coaxial cables;electrostatics;boundary value problems;scaled boundary finite element method;Schur decomposition
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- 0
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- 0
发布时间：2023-11-14 - 摘要：Abstract:In a batch operated crystallizer,the cooling crystallization kinetics of rifapention was studied. From experimental population density data of rifapention and the method of the size-independent growth rate,the nucleation and growth rate equations of rifapention were determined by direct fitting of population density data got from a series of batch crystallization experiments. It was shown that lower supersaturation,lower magma density and appropriate temperature are three key factors to get rifapention with bigger mean particle size.关键词：rifapention;nucleation rate;growth rate;population density
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发布时间：2023-11-14 - 摘要：Abstract:Nickel catalysts supported on activated carbon were prepared by excessive impregnation.The catalysts were studied by BET,XPS and XRD. The result showed that the active carbon pretreated by HNO3 can increase specific surface area and pore volume,improve oxygen-containing functional groups propotion. The Ni/AC catalyst pretreated by acid exhibits high desulfurization activity at low tempreture. The desulfurizaiton activity is apparently influence by pretreatment of the support with acid and metal loading.Ni/AC desulfurization catalyst is to be used at suitible reaction conditions.关键词：acid pretreated;catalyst;desulfurization;active carbon
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发布时间：2023-11-14 - 摘要：Abstract:A method of dry-sweating was applied to purify phosphoric acid hemihydrate crystals to obtain high purity phosphoric acid. The effects of operating parameters, such as sweating temperature, cooling rate, phosphoric acid concentration and sweating time on the removal and purification efficiency of Mg and Sb were investigated. The experimental results showed that the content and purification efficiency of impurities decrease with the increase of sweating temperature, the content of impurities in the product obtained at higher sweating temperature are lower. The content of impurities in the crystals formed at higher cooling rate during crystallization are more, and the impurities can be removed easily during dry-sweating, moreover the purification efficiency of impurities are lower, however the content of impurities in the final product are more. The less the initial content of impurities in the crystals is, the higher the purity of product is. Therefore, dry-sweating can be used to fine phosphoric acid.关键词：phosphoric acid;purification;dry-sweating
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- 10
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发布时间：2023-11-14 - 摘要：Abstract:Near infrared spectroscopy (NIR) technology was used to set up the quantitative model and fast determination of the content of traditional Chinese medicine geniposide extracted with the permeability method and purified using the macroporous resin .With the partial least squares (PLS) method to establish the models,the correlation coefficient (R) ,the root mean square error of calibration (RMSEC) and the root mean square error of prediction (RMSEP) of extracting process mode were 0.997 48,0.588,and 0.536,respectively,and 0.996 40,0.308,and 0.298,respectively,for purification process quantitative model. It was concluded that NIR is a fast method to quantify the effective component content of traditional Chinese medicine gardenia during extracting and purification process.关键词：near infrared spectroscopy technology;geniposide;extraction;purification
- 2613
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发布时间：2023-11-14 - 摘要：Abstract:The lubrication condition between the meshing teeth of filtering reducer is complex due to multiteeth contact.In order to solve this problem,an elastohydrodynamic lubrication (EHL) model of filtering reducer was established.The un-uniformed load distribution,detailed realistic contact geometry gap,and the machined surface roughness were all considered in the model.A complete numerical solution was achieved with the Newton-Raphson method(FEM).The hydrodynamic pressure and film thickness of lubricant along the line of action were calculated and the effect of teeth surface roughness to the lubrication property was also obtained.The results showed that the hydrodynamic pressure and the film thickness vary with disturbance and mutation along the line of action,the film thickness decreases and the lubrication status becomes worse when the surface roughness is taken into account.Hydrodynamic pressure and film thickness exist little difference between the sine wave shape roughness surface and the realistic machined roughness surface,and sine wave shape roughness is acceptable to model the machined roughness to some extent.关键词：filtering reducer;lubrication;Newton-Raphson;load distribution;line of action;geometry gap
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发布时间：2023-11-14 - 摘要：Abstract:Oil system is an important part to ensure the normal operation of the unit.Oil turbine is the core components of oil system for large-capacity steam turbine group over 600 MW.It was made currently through introducing technical drawings,but its internal flow mechanism and design method were few studied.Based on basic structure and operating principle of oil turbine components,reference to the design theory of radial and impulse turbine,the fundamental principle model of oil turbine was established by using velocity triangles and the impulse theorem.Its characteristic equation and key effect factors were presented,and it was verified through hydraulic performance numerical test model.On this basis,the parametric design model of the oil turbine was established.The intrinsic properties of oil turbine were found.Relative design principles were offered to oil turbine design.关键词：oil system;oil turbine;principle model;numerical simulation
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发布时间：2023-11-14 - 摘要：Abstract:The composite solutions were prepared by mixing the titanium dioxide sol in N, N dimethyl formamide (DMF) with the polyacrylonitrile (PAN) solution of DMF. The well-mixed solutions were then casted in a polytetrafluoroethylene mould to form membranes. After pre-oxidation and carbonization processes the carbon/nano-TiO2 composite catalytic materials were obtained and characterized. The results showed that the anatase TiO2 particles in 10～30 nm diameter were dispersed and inlaid in the carbon matrix with turbostratic graphite structure. With the increase of TiO2 content in PAN basement the surface TiO2 content of the composite membrane increases and the particles scale also increases. But the surface TiO2 content of the composite membrane is lower than that in interior. The turbostratic graphite hinders the phase transition of anatase TiO2 to rutile.关键词：carbon;nano-titanium dioxide;composite catalytic material;preparation;structure
- 3105
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发布时间：2023-11-14
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