J. T.Niu
,
L.J.Sun and P.Karjalainen 1) Harbin Institute of Technology
,
Harbin 150001
,
China 2) University of Oulu
,
FIN-90571
,
Oulu
,
Finland
金属学报(英文版)
For the great significance of the prediction of control parameters selected for hot-rolling and the evaluation of hot-rolling quality for the analysis of prod uction problems and production management, the selection of hot-rolling control parameters was studied for microalloy steel by following the neural network principle. An experimental scheme was first worked out for acquisition of sample data, in which a gleeble-1500 thermal simolator was used to obtain rolling temperature, strain, stain rate, and stress-strain curves. And consequently the aust enite grain sizes was obtained through microscopic observation. The experimental data was then processed through regression. By using the training network of BP algorithm, the mapping relationship between the hotrooling control parameters (rolling temperature, stain, and strain rate) and the microstructural paramete rs (austenite grain in size and flow stress) of microalloy steel was function appro ached for the establishment of a neural network-based model of the austeuite grain size and flow stress of microalloy steel. From the results of estimation made with the neural network based model, the hot-rolling control parameters can be effectively predicted.
关键词:
microalloy steel
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null
,
null
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null
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null
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null
周华杰
,
徐秋霞
功能材料与器件学报
doi:10.3969/j.issn.1007-4252.2008.06.002
利用三维模拟软件Davinci对体硅FinFET器件进行了详细的模拟.模拟结果显示体硅Fin-FET器件能够有效的抑止短沟道效应,具有驱动电流大、散热好、成本低等优点.为了获得好的亚阚值特性,Fin的厚度要比较薄,同时Fin的高度不能太低,以保持足够的高度来抑止短沟道效应.沟道可以采用低掺杂或未掺杂设计,从而减少沟道内杂质对载流子的散射作用和杂质涨落效应对器件性能的影响.另外,为了获得合适的器件阈值电压,体硅FinFET器件应当采用功函数在中间带隙附近的材料做栅电极,同时采用适当的功函数调节方法来获得合适的阈值电压.
关键词:
体硅
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FinFET
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新结构
王洪涛
,
王茺
,
李亮
,
胡伟达
,
周庆
,
杨宇
功能材料
利用三维器件模拟软件,研究了深亚微米三栅FinFET的短沟道效应,并模拟了阈值电压和亚阈值摆幅随硅鳍(fin)厚度和高度的变化情况.通过优化硅鳍厚度或高度,可以有效的控制短沟道效应.在进一步对深亚微米三栅FinFET的拐角效应进行二维数值模拟的过程中,并未观察到由拐角效应引起的泄漏电流.与传统的体硅CMOS结构有所不同,拐角效应并未使得深亚微米三栅FinFET性能变差,反而提高了其电学性能.
关键词:
三栅FinFET
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短沟道效应
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亚阈值摆幅
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拐角效应
余刘辉
,
黄维刚
,
赵旭
表面技术
doi:10.3969/j.issn.1001-3660.2009.05.007
为了提高AZ31镁合金的耐磨性能并扩大其在相关领域的应用,采用化学复合镀技术在AZ31镁合金基体上制备了Ni-P-TiN(纳米)复合镀层,同时制备Ni-P镀层进行比较.研究了复合镀层形貌、成分、硬度和耐磨性能与镀液中纳米"FiN颗粒含量的关系.结果表明,复合镀层和Ni-P镀层表面都是由胞状物排列而成;纳米TiN颗粒沉积于Ni-P-TiN(纳米)复合镀层中.当镀液中纳米TiN颗粒浓度为3g/L时,复合镀层硬度达最大值,为826HV,而Ni-P镀层只有508HV;同时复合镀层表现出优异的耐磨性能,在同等条件下其磨损失重只有Ni-P化学镀层的25%.
关键词:
AZ31镁合金
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化学复合镀
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纳米TiN颗粒
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耐磨性能
Journal of Materials Processing Technology
This paper mainly focuses on the folding which is the main defect on the inner surface of the inner grooved copper tube during ball spin forming. The material model and two-dimensional geometrical model of finite element simulation of multi-step ball spinning for forming inner grooved copper tubes have been built. The folding defects formed both on one side of the fin and on the bottom of inner grooves of the copper tubes had been analyzed according to the finite element results such as strain distribution, metal flow and contact state between the copper tube and the plug. Efficient measures have been proposed to prevent the folding defects. The SEM observation on the inner surface of the finished inner grooved copper tubes has been performed to illustrate the folding distribution and shape. Metallographic observation on the microstructure of cross-section of the copper tubes has been performed to analyze the forming process of folding. The results of the finite element simulation agree well with the experimental observation of the folding defects on the inner surface and the microstructure of cross-section of the inner grooved copper tubes. (c) 2006 Elsevier B.V. All rights reserved.
关键词:
inner grooved copper tube;ball spinning;finite element;folding
朱建锋
,
高积强
,
王芬
,
陈平
稀有金属材料与工程
研究了Ti,Al和TiO2混合粉体经无特殊气氛保护的高能球磨和真空热压烧结工艺原位合成了TiN/Al2O3复合材料,该材料的抗弯强度达到850 MPa,断裂韧性为5.5 MPa.m1/2.利用DTA,XRD及SEM等手段的分析测试结果,结合热力学计算,研究了该粉体的高能球磨过程和球磨粉体在后续热处理中的物相形成及转化规律.结果表明:在球磨过程中粉料吸附并溶解了空气中的N2和O2气,在后续热压烧结处理中首先原位反应形成了Ti2AIN,Al2O3以及TiAl,Ti3Al,TiAl3等金属间化合物相.随温度的升高Ti2AIN逐渐分解形成TiN相,当热压温度升高到1300℃时,其它物相基本消失,从而形成了FiN/Al2O3复合材料.
关键词:
高能球磨
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原位反应
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TiN/Al2O3
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力学性能
