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本文针对生产低合金中厚钢板出现超声波探伤缺陷的现象,分析探讨缺陷的产生原因及形成机理。从而采取有效措施,防止钢板缺陷的产生,提高探伤合格率。 相似文献
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本文主要介绍了压煮器管座角焊缝的超声波探伤中,应选用的探伤工艺、探伤方法和步骤,通过对探伤波形的分析,来进行缺陷的判断,以保证压煮器管座角焊缝的质量。 相似文献
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用压力容器对接焊缝超声波探伤过程中。在一定条件下会产生变型干扰波,很容易被误判为缺陷波。通过分析变型波的产生机理和总结实际探伤经验,明确了这种假设缺陷回渡产生的原因及特点。对压力容器焊缝超声波探伤有参考意义。 相似文献
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阐述了无缝钢管在轧制过程中产生的表面和内部缺陷的两种探伤方法,即涡流探伤和漏磁探伤。介绍了两种方法的基本原理,分析比较它们在无缝钢管探伤中的应用特点。 相似文献
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本文介绍了SUJ2棒材近表面缺陷的探伤方法,探讨了横波探伤技术在棒材近表面缺陷探伤工艺中的有关入射角、探测范围、水层等技术参数的数学表达式,经验证采用横波探伤技术对棒材近表面缺陷的探伤是一项有效的探伤方法,满足了SUJ2棒材质量控制的要求. 相似文献
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本文主要分析了15MnNbR钢的探伤缺陷,找出了探伤合格率不高的原因。提高该钢种的探伤合格率,对提高钢种质量、增强重钢产品的市场竞争力有积极的意义。 相似文献
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改变传统使用加工中心加工宽曲面的加工方法,而是创新采用了一种新方法,较以前大大的提高了加工效率,降低了加工成本,是一种值得加工类似宽曲面推广的新方法. 相似文献
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介绍变压器故障诊断的改良三比值法。针对改良三比值法的不足,提出了基于改良三比值法的综合诊断,并且设计了与之相关的编程流程图。与改良三比值法相比较,此方法具有更好的故障识别效果。 相似文献
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利用观察法、岩相法和X射线衍射法定量分析了某钢厂高炉渣中非晶态含量,得到该高炉渣中非晶态含量大于95%的结论。三种方法中,观察法最简单,但易受人主观因素影响;岩相法需要一定的经验来判断;利用X射线衍射法可以较客观定量高炉渣中非晶态含量。 相似文献
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The authors describe a new simple noniterative, yet efficient method to estimate the risk ratio in studies using case-parental control design. The new method is compared with two other noniterative methods, Khoury's method and Flanders and Khoury's method, and with a maximum likelihood-based method of Schaid and Sommer. The authors found that the variance of the new estimation method is usually smaller than that of Khoury's method or Flanders and Khoury's method and that it is slightly larger than that of the maximum likelihood-based method of Schaid and Sommer. Despite the slightly large variance of the new estimator compared with that of the maximum likelihood-based method, the simplicity of the new estimator and its variance makes the new method appealing. When genotypic information for only one parent is available, the authors also describe a method to estimate the risk ratio without assuming Hardy-Weinberg equilibrium or random mating. A simple formula for the variance of the estimator is given. 相似文献
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Jinsong Huang 《Canadian Metallurgical Quarterly》2002,15(2):64-71
By adopting the energy method, a method of calculating the stability of the rotational composite shell is presented that takes into account the influence of nonlinear prebuckling deformations and stresses on the buckling of the shell. The relationships between the prebuckling deformations and strains are calculated by nonlinear Karman equations. The numerical method is used to calculate the energy of the whole system. The nonlinear equation is solved by combining the gradient method and the amended Newton iterative method. A computer program is also developed. Examples are given to demonstrate the accuracy of the method presented in this paper. 相似文献
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目前玲珑金矿采矿方法主要为浅孔留矿采矿法,但由于玲珑矿田内部分矿体的产状为缓倾斜且上下盘均不稳固,传统的浅孔留矿采矿法不适用于缓倾斜矿体的开采,为此,在回采矿房内留有处于静止不动状态的部分矿石,以支撑围岩,防止其破坏和脱落,保证安全回采.介绍了静态留矿采矿法的采场结构及回采工艺,应用实践表明,采矿损失率4.8%,矿石贫... 相似文献
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For simply finding local analytic solution, the time derivative in the traditional finite analytic (FA) method is generally replaced with a first-order finite difference approximation as a source term. However, this may induce excessive numerical diffusion, especially for advection-dominated transport problems. In this paper, a fractional steps scheme of the FA method without using the finite difference approximation to time derivative is proposed by applying the one-dimensional FA method whose local analytic solution is obtained from both spatial and time domains, together with the method of fractional steps. Four hypothetical examples, including two-dimensional and three-dimensional cases, are employed to investigate this newly proposed method as compared with the traditional FA method, the optimal unsteady FA method, and the alternating direction scheme of the hybrid FA method. The results show that the fractional steps scheme of the FA method can greatly diminish numerical diffusion and is superior to the other methods compared herein. 相似文献
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油中溶解气体组分含量的色谱分析法是监督变压器运行的重要测试手段,对已发生故障的严重程度及趋势也有明确的比值判定法。同时在故障发生后对绝缘系统完好程度的判定也要依靠色谱检测。实际运行经验表明色谱法是一项成熟的技术,在现场应用效果理想。 相似文献