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31.
32.
Kazi Md. Shorowordi Md. Mohar Ali Bepari 《Journal of Materials Engineering and Performance》2002,11(6):625-630
Carbon (0.13%) steel samples containing about 0.48% molybdenum (Mo) singly and in combination with nickel (Ni) were carburized in a natural Titas gas atmosphere at a temperature of 1223 K (950 °C) and at a pressure of about 0.10 MPa (15 psia) for time periods ranging from 1–4 h followed by slow cooling in the furnace. Their microstructure was studied by optical microscopy. The austenite grain size of the case and the case depths were determined. It was found that Mo and Ni alone and in combination decrease the thickness of the cementite network near the surface of the carburized case of the steels. However, Ni is found to be more effective than Mo in decreasing the thickness of cementite network. Both Mo and Ni enhance the formation of Widmanstätten cementite plates at the grain boundary and within the grains near the surface of the carburized steels. However, Ni alone is more effective than Mo in the formation of Widmanstätten cementite plates. In the presence of Ni, Mo is much more effective in the formation of Widmanstätten cementite plates than Mo in absence of Ni. It was also revealed that both Mo and Ni increased the case depth. Ni is more effective than Mo in increasing the case depth. The combined effect of Mo and Ni is much greater than that of either Mo or Ni alone in increasing case depth. Mo as Mo carbide (Mo2C) particles refined the austenite grain size of the carburized case. Ni in solution was not found to have any effect in restricting grain growth of austenite, but the presence of Ni enhances the austenite grain size refining effect of Mo in the carburized case. 相似文献
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Xiaofeng Liao Xueming Li Jun Pen Guanrong Chen 《International Journal of Communication Systems》2004,17(5):437-445
In this paper, a simple image secure communication scheme based on the chaotic Chebyshev map and chaos synchronization is proposed. The scheme relies on the excellent correlation property of chaotic sequences, which is very desirable for secure image communication. The results obtained by computer simulation indicate that the transmitted source image can be correctly and reliably recovered using the proposed scheme, even through a noisy channel. Notably, the scheme possesses relatively high security and can be easily implemented. Moreover, the quality of the recovered image is satisfactory, quantified by such common criteria as the bit‐error rate performance. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
35.
论述了国内外金相测定球化退火钢脱碳层深度的标准方法和常用方法存在的不准确性和不适用性问题,提出了解决问题的途径——定量金相法。 相似文献
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对液压胀形轧辊(即国外的VC轧辊)辊套热装后的弹性变形进行了有限元分析,给出了确定油槽最小深度的计算公式。本文的有限元计算结果与实验结果吻合,某些结论可为液压胀形轧辊的结构设计提供理论依据。 相似文献
39.
A roll-coating experimental system is used to study the effect of pre-wetting on dynamic contact angles, the interfacial displacement depth, and the associated phenomenon of air entrainment. The system consists of a roll, which is horizontally rotating in a liquid pool. The dynamic contact angle is recorded by a macrophotography system. The test liquids are glycerol solutions with viscosities in the range 104 < μ < 748 mPa · s. The value of (μV/ρg)0.5 is taken as the characteristic length to be used in the dimensionless relationships which correlate experimental measurements. The effect of base layer entry angle into the liquid pool on the dynamic contact angles and other flow parameters is studied. Comparison is made with measurements in dry tape-coating and other pre-wet roll–coating systems. 相似文献
40.
高分辨率双侧向测井响应数值模拟分析 总被引:6,自引:0,他引:6
我国自行研制的新型的高分辨率双侧向测井仪已逐渐投入大规模的生产应用,可为解决油田薄层油气藏的勘探开发问题提供有力的支持。本文利用有限元方法对新型的高分辨率双侧向测井仪及国内目前大规模应用的常规双侧向测井仪的分层能力、探测深度、侵入影响和井眼影响等响应特征进行了数值模拟,并对其测井响应进行了对比分析。数值模拟表明:与常规双侧向测井相比,虽然高分辨率双侧向测井资料井眼的影响更复杂,但测量结果既能得到较高纵向分辨率,又具有较深的径向探测深度,基本上可以取代常规双侧向测井仪在测井中应用。文中数值模拟结果可以为测井作业人员和解释人员在资料验收及解释处理等方面提供参考和指导。 相似文献