共查询到20条相似文献,搜索用时 906 毫秒
1.
利用磁光传感器获取紧密对接微间隙(0~0.1 mm)焊缝磁光图像.针对传统形态学图像处理方法检测微间隙焊缝时容易出现边缘细节丢失的问题和存在检测精度不高的缺点,在四个不同方向上各选取三种不同尺度的结构元素,应用多尺度多结构元素形态学方法提取微间隙焊缝边缘信息,并与小波边缘检测和Sobel边缘检测结果相比较.在激励磁场变化情况下进行三组试验,分别采用多尺度形态学算法和传统形态学算法提取焊缝中心位置.结果表明,多尺度多结构元素形态学算法能更有效地检测出微间隙焊缝中心位置,为紧密对接焊缝的识别与跟踪控制提供试验依据. 相似文献
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针对微间隙(小于0.1 mm)对接焊缝,通过对焊件施加感应磁场,并利用法拉第旋光原理构成的磁光传感器,获取焊缝磁光图像.为了获取焊缝的准确位置,研究一种焊缝磁光图像的小波多尺度信息融合边缘检测方法.对焊缝磁光图像进行3层小波分解,获得包含焊缝边缘信息的小波高频图像.根据各尺度高频信息包含的细节丰富度,融合各尺度高频图像,然后用小波模局部极大值对融合图像进行边缘检测,得到抗噪性和连续性好、定位精度高的焊缝边缘,最后进行焊缝跟踪试验.结果表明,磁光图像小波多尺度信息融合是一种有效的焊缝边缘提取方法,适用于磁光成像传感的微间隙焊缝跟踪图像处理过程. 相似文献
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针对大功率(10 kW)光纤激光焊接304不锈钢紧密对接微间隙焊缝(焊缝间隙小于0.1 mm),通过高速像机摄取熔池近红外热像并分析其特征,分析和处理熔池热像特征,提取激光束偏离焊缝位置的信息,探索激光束与焊缝偏差的信息表征.利用激光深熔焊的匙孔效应,研究焊缝在固态与液态交界处不稳定边缘特征点,提出一种角点检测法实现微间隙焊缝偏差的检测.结果表明,熔池红外热像角点密集分布中心与焊缝偏差有密切的关系,通过角点分布密度可以有效判断焊缝偏差状态. 相似文献
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针对激光焊接平板对接微间隙焊缝(间隙小于0.1 mm),研究彩色图像信息的磁光成像焊缝检测算法,为微间隙焊缝的精确跟踪提供一种新方法. 采用磁光传感器采集焊接过程的焊缝区域图像,对焊缝磁光图像在RGB(red, green, blue)和HSV(hue, saturation, value)彩色空间的灰度分布进行分析,提取RGB图各分量的灰度图,根据各分量灰度分布曲线确定阈值提取焊缝边缘,合成3个分量的焊缝边缘得到焊缝过渡带轮廓;对HSV图的每个分量图灰度直方图进行分析确定阈值,然后综合形成单一的焊缝过渡带分割图像. 结果表明,该方法能有效检测肉眼难以分辨的微间隙焊缝. 相似文献
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针对激光焊接微间隙焊缝(间隙小于0.1 mm),研究提高磁光传感检测焊缝精度的BP神经网络修正方法.以碳钢平板对接激光焊为试验对象,利用磁光传感器检测焊缝区域磁场分布并成像.通过分析焊缝处磁场成像并应用BP神经网络修正磁光传感器得到焊缝中心数据,有效避免焊缝磁光图像低对比度和强噪声干扰问题.经过在不同焊接速度试验下的测试,四组神经网络试验的焊缝位置误差的绝对平均值都在0.015 mm左右,BP神经网络测量误差比磁光成像直接测量平均减少约28%.BP神经网络修正磁光成像测量技术可有效识别微间隙焊缝,为解决激光焊接微间隙焊缝过程自动识别和跟踪焊缝的难题提供了一种新方法. 相似文献
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基于视觉传感的焊缝中心检测技术研究 总被引:1,自引:0,他引:1
通过视觉传感器获取焊缝图像,采用多种去噪技术对焊缝图像中的噪声进行滤波试验。针对焯缝图像中的干扰噪声特性,对各种滤波方法进行了分析和比较,并对滤波效果较好的焊缝图像进行边缘检测计算。提出3种识别焊缝特征的组合图像处理方法,并研究提取焊缝中心特征信息的效果和精度。试验结果表明,对焊缝图像采用Wiener滤波与Robert边缘检测算法能较好地提取焊缝中心位置的特征信息。 相似文献
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Deng-Kui Zhang Guo-Qing Wang Ai-Ping Wu Ji-Guo Shan Yue Zhao Tian-Yi Zhao Dan-Yang Meng Jian-Ling Song Zhong-Ping Zhang 《金属学报(英文版)》2019,32(6):684-694
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone. 相似文献
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After nearly two years'tense construction the first phase of industrialized base of Shenyang Research Institute of Foundry 《中国铸造》2008,5(1):63-64
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation. 相似文献
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Z. Sun S.L. Zheng Y. Zhang 《金属学报(英文版)》2007,20(3):187-192
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process. 相似文献
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R. González-Martínez 《金属学报(英文版)》2007,20(4):235-240
The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke. 相似文献
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目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。 相似文献
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The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C). 相似文献
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Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems. 相似文献
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This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before. 相似文献
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Chao Yang He-Fei Huang Massey de los Reyes Long Yan Xing-Tai Zhou Tian Xia De-Liang Zhang 《金属学报(英文版)》2015,28(7):809
Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties. 相似文献
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Lei Li Bo Xu Wei-Ping Tong Hui Zhang Chun-Yan Ban Li-Zi He Zhi-Hao Zhao Yu-Bo Zuo Qing-Feng Zhu Jian-Zhong Cui 《金属学报(英文版)》2015,28(6):725
A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed. 相似文献