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21.
高碱度渣精炼对轴承钢夹杂物的影响 总被引:4,自引:2,他引:4
对国内外几家特钢厂生产的GCr15轴承钢中夹杂物进行了试验分析 ,结果表明 ,在炉渣碱度较高 (CaO SiO2 =3~ 4 5 )的精炼条件下 ,低氧含量 (≤ 7× 10 - 6 )的轴承钢中夹杂物主要为 :含Cr、Fe的复合MnS夹杂 ,TiN型夹杂 ,具有不同MgO含量的镁铝尖晶石 (MgO·Al2 O3)夹杂 ;未发现单独存在的铝酸钙型 (CaO·Al2 O3)球状夹杂物。随渣碱度提高和钢中氧含量降低 ,镁铝尖晶石夹杂物中的MgO含量增加 ;当渣系碱度CaO SiO2 达 4 5时 ,镁铝尖晶石夹杂物中含有CaO。 相似文献
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对不同硫含量的16MnR(HIC)中厚板进行HIC试验及夹杂物分析,结果表明,16MnR(HIC) 氢致裂纹敏感性随S含量增加而增强,硫化物夹杂达到2.0级仅出现氢鼓泡,大于2.0开始出现氢致裂纹以及氢鼓泡,小于0.5级抗氢致裂纹性能优良。 相似文献
26.
《Drug development and industrial pharmacy》2013,39(6):533-540
Ofloxacin (OFX) is a fluorquinolone characterized by photochemical instability. With the goal to improve its photostability in aqueous solutions, the complexation of ofloxacin with β-cyclodextrin was investigated. The complexes showed a water solubility enhancement of approximately 2.6 times; nevertheless, the photodegradation of ofloxacin was not reduced. The complexes obtained were characterized by thermal and 1H nuclear magnetic resonance (NMR) analysis, which revealed an interaction between ofloxacin and β-cyclodextrin. The last analysis indicated that only partial inclusion of the N-methylpiperazinyl moiety occurred, which can explain the fact that photostabilization was not improved. This partial inclusion phenomenon could be explained also by computer-aided molecular modeling. 相似文献
27.
《国际计算机数学杂志》2012,89(1-4):247-258
The problem of minimizing the number of zero elements that become non-zero during the computation when a sparse symmetric matrix is reduced to a triple diagonal form, either by Givens' or Householder's method, is discussed. Algorithms for minimizing the growth of such non-zero elements are given. 相似文献
28.
Eshelby’s inclusion problem is implemented by boundary integral equation method (BIEM) and parametric dislocation dynamics (PDD), which are surface- and line-discretization approaches based on Green’s function method. In BIEM calculations, unknown constraint displacements at the inclusion boundary are deduced from surface integration associated with eigenstrain, and then unknown tractions are solved by a linear system of equations. Field quantities and strain energy are readily calculated by using the boundary tractions and displacements. In the meantime, inclusion stress by PDD is directly calculated by line integration over the dislocation elements, where the burgers vector satisfies geometrical argument of eigenstrain of inclusion. In particular, double line integral formula associated with dislocation interaction is utilized for elastic energy calculation. Computation efficiency of BIEM and PDD is mutually compared as a function of the number of Gauss integration points. Accuracy of field quantities and strain-energy of inclusion are verified by comparison of numerical results to analytical solutions. 相似文献
29.
With the advance in composite mechanics and micromechanics, there are increasing demands for analytical solutions of inclusion problems in a bounded domain. To echo this need, this study is focused on establishing explicit expressions of elastic fields for a 2D elastic domain containing a circular inclusion at center. Unlike the configuration in the classical Eshelby formulation, the elastic domain in this study is bounded and has shapes other than a circle. To circumvent the mathematical difficulty in solving Green’s function in a finite domain, an approach powered by complex potential method, which has been successfully employed to formulate the elastic fields for inclusion problems where matrix is unbounded or bounded by a circle, is extended to finite domains displaying complicated shapes, particularly, a Pascal’s limaçon and a curved square (an approximation of perfect square) in this study. In order to take advantage of the mathematical simplicity inherent in expressing a circular geometry, conformal mapping is used to transform the complex geometry of the finite domain of interest to a unit circle. The governing complex potentials, which capture the discontinuity on the inclusion–matrix interface due to the uniform eigenstrain within the inclusion, are formulated with the aid of Cauchy integral and then explicitly identified by satisfying the prescribed boundary conditions. In this study, the displacement fields for finite domains bounded by a Pascal’s limaçon and a curved square are obtained based on Dirichlet (displacement) boundary conditions imposed by the far field strain. In addition to asymptotical behaviors, firm agreement is also achieved when the analytical solutions based on complex potentials are compared with the FEM results. Furthermore, inverse of the conformal mapping is discussed here in order to get the explicit expression for elastic fields. 相似文献
30.
对超重力场条件下Cu熔体中的氧化夹杂进行受力分析,建立夹杂颗粒沿超重力方向上的运动速度与运动距离方程,并通过理论计算分析重力系数、夹杂物特性(尺寸、种类、含量)以及熔体温度对夹杂物在超重力场中运动行为的影响。计算结果表明,超重力场能强化Cu熔体中氧化夹杂的定向分离过程,其中重力系数、夹杂物尺寸、夹杂与熔体之间密度差(固液密度差)对夹杂颗粒运动行为影响较大。较大的重力系数、夹杂物尺寸以及固液密度差均有利于夹杂物的上浮去除。 相似文献