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1.
Aiming at the low efficiency and precision of hot rail steel surface faults detecting at present,a suit of surface defect detection system of hot heavy rail based on the machine vision is put forward. Multi-CCD cameras are used to collect pictures. According to the geometric characteristics of the heavy rail and its defect characteristics of high-frequency region,six angle shot is used for heavy rail,and then various image processing technology are adopted in workstation. The system adopts improved Hough transform to get surface faults and Kohonen network to make a classification for the characteristics of low SVM training algorithm. The above key machine vision technology for detection of hot heavy rail surface defects greatly improves the speed and accuracy of testing and the detecting correct rate arrives over 85%.  相似文献   

2.
Pearlitic steel is composed of numerous pearlitic colonies with randomly distributed orientations,and each colony is composed of many alternatively arranged parallel lamellas of ferrite and cementite.The pearlitic steel with fine interlamellar spacing possesses excellent mechanical properties,such as high strength,good resistance against wear,and high fatigue life,etc. Based on the inconsistency of the deformation between the two phases,a strain_equivalent and non_local constitutive model is proposed. Using this model,the effect of the interlamellar spacing of peailitic steel,a fundamental parmeter of the microstructure of pearlitic material, on its macroscopic mechanical behavior can be described without changing the local material parameters for each phase of the material.The asymmetrical cyclic plasticity of both the hot_rolled and the off_line full_length quenched pearlitic steel PD3 is analyzed.The comparison between the computational and the experimental results shows satisfactory agreement.  相似文献   

3.
According to the character of PD in GIS, the authors design four kinds of GIS defection models. The GIS gray intensity images are constructed based on mass specimens gathered by the ultra - high frequency and high speeds systems, Aiming at the PD characteristics and its defections, A PCA-FDA method is put forward based on PD images. The principal component analysis is employed to condense the dimension of PD images, then the optimal sets of statistically uncorrelated discriminant vectors are extracted, and the minimum distance classifier is constructed as classifier. The identified results show that this method can effectively elevated the discrimination of the four kinds of defects in GIS PD.  相似文献   

4.
拟巫山淫羊藿种子休眠特性的初步研究   总被引:2,自引:0,他引:2  
为全面掌握拟巫山淫羊藿种子的休眠特性并筛选有效的打破休眠的方法,通过设置不同的处理,观测不同处理条件下胚是否萌动、胚开始萌动所需时间、胚生长和发芽情况。结果表明:拟巫山淫羊藿种子休眠属形态生理休眠(MPD),先暖温(15℃左右)后低温(4℃)、赤霉素处理加低温这两种方法可有效打破其休眠,发芽率皆大于80%;且拟巫山淫羊藿种子休眠可能含形态休眠(MD)和2种类型的生理休眠(PD):暖温(15℃左右)处理有助于解除第1种PD,这样胚才能萌动(胚萌动率高)并生长,单独4℃、27℃处理,胚萌动率极低,分别为20%、6.7%;低温(4℃)能解除MD;而完成形态后熟的种子只有继续低温才能解除第2种PD而萌发,未经过低温的处理组发芽率皆为0%。GA3可以替代最初的暖温破除第一种类型的PD。  相似文献   

5.
Based on a thermomechanically consistent mechanical model, the constitutive law for a class of complex two-phase materials with locking-in inter-phase residual stress capability is proposed. The developed model contains the current plastic strain in its hereditary integral so that the main features of the above materials subjected to cyclic loading can be well described. The developed model can include both the endochronic constitutive equation and Bower' s empirical formula as special cases. The cyclic plasticity and ratcheting of OFHC copper (single-phase material) and rail steel BS1l(two-phase material)are analyzed and compared with experimental results  相似文献   

6.
The qualities of 55CrSiA oil tempered spring steel wire and not as good as that of JIS G3566-77. This conclusion resulted from the comparative tests which were for the valve springs of FM147 Engine being seperately made of the two kinds of spring steel wires mentioned above acording to the same processing and test methods.  相似文献   

7.
尿液嘌呤衍生物法作为一种估测瘤胃微生物蛋白质合成量的新方法,克服了原有方法的缺点,简单易行,通过欧洲牛羊的实验证明该方法与其它方法的测定结果有很好的一致性,但此方法亦有其不足。由于尿中嘌呤衍生物排出量受动物品种的影响很大,不同品种间无通用性,所以现有的研究成果不能用于中国品种牛,更难以使该方法应用于生产。而国内在此方面的报道很有限,所以急需建立各品种反刍动物的估测模型,扩大该方法的应用范围。试验采用3头月龄(22±0.2),体重为(641±26.889)kg,体况相近的中国荷斯坦成年公牛,设计3×3的拉丁方,通过调整日粮精粗比来考察可消化有机物进食量对中国荷斯坦成年公牛尿嘌呤衍生物(PD)排出的影响。结果发现,试验牛尿中嘌呤衍生物中尿囊素大约为73% ̄88%,黄嘌呤和次黄嘌呤的含量很小,可以忽略不计,与以往对成年反刍动物的研究结果相似,与同个体犊牛期的研究结果相反。PD的排出量随可消化有机物(DOMI)和可消化粗蛋白(DCP)进食量升高而上升,存在较强的相关性(R2=0.88,n=9),其排出水平为414.09 ̄975.59mmol/d。肌酐酸的排出较稳定,各处理间差异不显著(P>0.05)。PDC与DOM和DCP进食量存在正相关,这与以往成年反刍动物的研究结果是相似的,与同个体犊牛期的研究结果相反,但相关性较弱。  相似文献   

8.
This paper systematically presents the experiment about the adhesive and shearing strengthbetween the concrete member poured with two kinds of steel form and the cement mortar on the membersurface. By the comparison of three groups of experiments, this paper draws a conlusion tha the adhesive and shearing strentgh between concrete member and cement mortar could be considerably increased if the special-shaped steel form was applied.  相似文献   

9.
This paper first discusses the limited effect of steel fibre reinforcement on plain concrete and reinforced concrete. Then, making a comparison among the test results of three full-scale top corner joint assemblies of frame, in which only two of them are added with steel fibres in joint zone. The advantageous and disadvantageous influence in anti-seismic aspect is investigated after adding steel fibres in the joint zone. Finally, this paper gives an overall comment on the application future of using the steel fibres in every kinds of joint of anti-seismic reinforced concrete frame.  相似文献   

10.
The flexural performance of the beams reinforced with both non-prestressed bars and prestressed bonded FRP bars was theoretically analyzed. Both the CFRP bar and the AFRP bar were taken as the representatives in the study. Correlativity of two kinds of balanced relative depth of compressive area, respectively corresponding to the yield of steel bar and to the rupture of FRP bar, was investigated. Therefore the influence of performance parameters of FRP on the flexural failure modes was analyzed. The results indicate that failure modes and two kinds of balanced relative depth of compressive area are with direct correlation, and the latter is directly influenced by the performance of the FRP bars. Adopting the short-term performance parameters or the long-term performance parameters, which considers the environmental factor, creep fracture factor, relaxation factor and materials coefficiency, would have different results. Failure mode I is the ideal one, while the others should be avoided. Prestressed control stress of CFRP bars with low-ductility should not be too high, otherwise the rupture of CFRP bars will happen before the yield of steel bars.  相似文献   

11.
The problem of identification of partial discharge phenomena occurring in a transformer insulating system is addressed. Under the assumption that different PD sources can produce pulse of different PD distributions, five typical artificial defects have been designed to compare the PD distributions coming from different sources, such as internal voids, surface and corona discharges. In this aim, Weibull distribution has been introduced to estimate the parameters and the least square methods (LSM) have been used to estimate the parameters. The goodness of fit to a Weibull distribution is checked by the Cramer-von-Mises (CVM) test. It is shown that the probability function fits well the partial discharge height distribution. By this way,different discharge sources can be distinguished. by Weibull parameter. In addition, the recognition of two or more PD phenomena simultaneously active is approached by means of an additive Weibull distribution. It allows quantities related to each of the two or more superimposed PD phenomena to be estimated, according to the Weibull parameters and the standard mean quantities.  相似文献   

12.
尿液嘌呤衍生物法作为一种估测瘤胃微生物蛋白质合成量的新方法,克服了原有方法的缺点,简单易行,通过欧洲牛羊的实验证明该方法与其它方法的测定结果有很好的一致性,但此方法亦有其不足。由于尿中嘌呤衍生物排出量受动物品种的影响很大,不同品种间无通用性,所以现有的研究成果不能用于中国品种牛,更难以使该方法应用于生产。而国内在此方面的报道很有限,所以急需建立各品种反刍动物的估测模型,扩大该方法的应用范围。试验采用3头月龄(22±0.2),体重为(641±26.889)kg,体况相近的中国荷斯坦成年公牛,设计3×3的拉丁方,通过调整日粮精粗比来考察可消化有机物进食量对中国荷斯坦成年公牛尿嘌呤衍生物(PD)排出的影响。结果发现,试验牛尿中嘌呤衍生物中尿囊素大约为73%~88%,黄嘌呤和次黄嘌呤的含量很小,可以忽略不计,与以往对成年反刍动物的研究结果相似,与同个体犊牛期的研究结果相反。PD的排出量随可消化有机物(DOMI)和可消化粗蛋白(DCP)进食量升高而上升,存在较强的相关性(R2=0.88,n=9),其排出水平为414.09~975.59mmol/d。肌酐酸的排出较稳定,各处理间差异不显著(P>0.05)。PDC与DOM和DCP进食量存在正相关,这与以往成年反刍动物的研究结果是相似的,与同个体犊牛期的研究结果相反,但相关性较弱。  相似文献   

13.
Cement is a traditional tailings cementation material, which causing the high tailings backfill cost. However, the utilization rate of industrial waste residue, such as steel slag and fluorgypsum, is low. So the steel slag-blast furnace slag-fluorgypsum-based cementation materials preparation with industrial waste residue substitutes for cement. As a result, its cementation tailings performances must be studied. According to mortar fluidity and bleeding quantity of tailing cementation slurry at different time and compressive strength change trend at different hydration ages, the performance of steel slag-blast furnace slag-fluorgypsum-based cementation materials is significantly better than P·O42.5 grade cement and two kinds of commonly used cementation agents in China. After soaking for three days, the pH value of these tailings solidification bodies leaching liquid is less than 9.0, which is much lower than the pH values of three kinds of high alkaline tailings cementation materials mentioned before. Leaching liquid fluorine ion concentration is extremely low. With less impact on environment. SEM analysis also show that these tailings solidification bodies mixing with the steel slag-blast furnace slag-fluorgypsum-based cementation materials have relatively dense microstructure.  相似文献   

14.
A new feature extraction method is proposed to recognize different types of partial discharge (PD) signals. Firstly,four typical categories of PD artificial defect models are made and S transform (ST) is employed to obtain a time-frequency representation of the recorded UHF signals. Then,two-directional two-dimensional principal component analysis ((2D) 2PCA) is applied to compress the ST amplitude (STA) matrix to extract features. Finally,support vector machine (SVM) combined with particle swarm optimization (PSO) algorithm is introduced to accomplish the recognition of experimental samples. Classification results demonstrate that the average recognition rate of (10,5) combination is the highest while the one of (5,5) combination is the lowest among four kinds of feature dimension combinations. Moreover,PSO can obviously improve the classification performance of SVM. Specifically,all the average recognition rates of PSO-SVM are higher than 94.43%and the maximum value comes to 97.67%. Therefore,the feature sets extracted by ST and (2D) 2PCA can not only achieve dramatic dimension reduction,but also retain the major information of original data. It is proved that the proposed algorithm can obtain ideal results in PD pattern recognition.  相似文献   

15.
Three crosses of cowpea (Vigna unguiculata [L.] Walp) were used to assess the effectiveness of two selection procedures in cowpea. The selection procedures were pedigree selection (PD) and single seed descent selection (SSD). Lines developed through each procedure were yield tested and selected at F6 and F7 for PD and SSD, respectively. The selected lines for both procedures were compared at F8 for grain yield per plant (YLD), number of pods per plant (NPO), and pod development period (PDP), in two locations. Lines developed through both procedures differed more in their population means than in the performance of their top 10% or highest yielding lines. There was no consistent relationship between magnitude of genetic variability and percentage of superior lines obtained from each procedure. Both procedures have been effective in producing superior genotypes for yield and number of pods. The PD method produced superior transgressive segregants in two out of the three crosses for PDP. SSD allowed a more rapid generation than PD.  相似文献   

16.
A micro/macroscopic analysis of PD3 pearlitic steel with layered microstructure is carried on.Based on the compatibilit conditions of stress and strain at the interface between two layers as well as the mixed law of composites,constitutive equations of an effective homogeneous inclusion are obtained.combining these equations with the K B W self consistent model,the micro macroscopic transition has been estabilished.It turns out that the analysis is capable of determining the overall responses of materials as well as local stress evolution in microstructure under monotonic and cyclic loading.It is found that stress in the thin cementite layer is very high.This is caused by intersification of the local plastic flow of the soft ferrite layer in which more loading is transferred cycle by cycle to the hard phase.Furthermore,a strength dimension law that the strength is inversely proportional to the square root of the layer thickness is developed to explain the high strength of the cementite layer.  相似文献   

17.
In order to identify the affect of vanadium in pearlite transformation and the regularity of the precipitation, the effect of vanadium content on VC precipitation in PD3 steel has been studied by electrochemical extraction and TEM. The results show that the solid solubility limit of vanadium in the ferrite and Fe 3C is 0.09% and 0.23% respectively, that vanadium exist mainly as solid solution and a few VC particles are precipitated in disordered way in case of the vanadium content being below 0.21%, that VC particles are precipitated in excess of saturated solubility, and that a lot of VC particles are precipitated in disordered and "interphase precipitated" way in case of the vanadium content being above 0.21% and arrive at 0.33%.  相似文献   

18.
A fuel system evaluation method was introduced to select the proper high pressure injection system for diesel engines. Using this method, the second generation common rail system of BOSCH Company was selected for use in the 4JB1 diesel engine. Based on this common rail system, a fuel supplying model was built using AMESim. The model included a high pressure pump sub module, a pressure control valve sub module, an injectors sub module, and a connecting pipes sub module. Through model simulation, the influences of parameters (e.g., rail volume, high pressure pipe length and diameter) on pressure fluctuations and pressure building were studied. Rail pipe system parameters were selected based on simulation results. Experimental results show the rail pipe parameters could satisfy the needs of rapid pressure response and low pressure fluctuations for common rail diesel engines.  相似文献   

19.
The method to determine the crystallinity of solid slag film is established by analyzing the DSC curve of solid slag film and corresponding quenched slag. The accuracy of the method is investigated by measurements of prepared samples whose crystallinity is given. In addition, the solid slag films of mold slags used to cast medium carbon steel and low carbon steel are obtained by heat flux simulator in laboratory, and the crystallinity of the two kinds of slag film are also measured by DSC method. Experimental results indicates that the crystallinity of solid slag film can be determined by comparing the crystallization enthalpy of solid slag film and corresponding quenched slag during heating process, and the relative error is within 5.03%. For medium carbon steel, the crystalline fraction of solid slag film is 88.6%, while the crystalline fraction of solid slag film corresponding to low carbon steel is 55.0%. The results are consistent with actual structure of solid slag films.  相似文献   

20.
Pod dehiscence (PD) prior to harvest results in serious yield loss in soybean. Two linkage maps with simple sequence repeat (SSR) markers were independently constructed using recombinant inbred lines (RILs) developed from Keunolkong (pod-dehiscent) × Sinpaldalkong (pod-indehiscent) and Keunolkong × Iksan 10 (pod-indehiscent). These soybean RIL populations were used to identify quantitative trait loci (QTLs) conditioning resistance to PD. While a single major QTL on linkage group (LG) J explained 46% of phenotypic variation in PD in the Keunolkong × Sinpaldalkong population with four minor QTLs, three minor QTLs were identified in the Keunolkong × Iksan 10 population. Although these two populations share the pod dehiscent parent, no common QTL has been identified. In addition, epistatic interactions among three marker loci partially explained phenotypic variation in PD in both populations. The result of this study indicates that different breeding strategies will be required for PD depending on genetic background.  相似文献   

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