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
,
null
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null
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null
Physica Status Solidi a-Applications and Materials Science
In MnAs(1-x)P(x) compounds (x = 0.006 and 0.01), prepared by mechanical alloying, the thermal hysteresis is greatly reduced from about 10-30K in MnAs-based compounds, prepared by conventional melting, to 2K for x = 0.01 (or 4K for x = 0.006). Such obvious hysteretic reduction is ascribed to the grain-size effect, largely due to the preparation method of mechanical alloying. Meanwhile, a maximum value of the magnetic-entropy change Delta S(M) of 11.3 J/kgK for a field change of 2 T is obtained at 294.5K for MnAs(0.994)P(0.006). The study on the MnAs(1-x)P(x) system and also the effect of the preparation technology may be beneficial for the realization of magnetic refrigerants for application at room temperature. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
关键词:
magnetocaloric effect;mechanical alloying;thermal hysteresis;gd-5(si2ge2);transition;mnas
朱佳庆
,
何俊伟
,
李云德
原子核物理评论
计算了pp和p碰撞中J/ψ的领头阶光生过程的产额。运用非相对论量子色动力学回顾了重夸克偶素产生的色单态机制与色八重态机制,并将它们分别用于处理直接光子过程和分解光子过程。通过与J/ψ产生的领头阶结果的对比可以看出,光生过程对J/ψ产额的修正在大横动量区域变得明显。
关键词:
光生过程
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大横动量区域
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重夸克偶素
Doris Smith
,
Ken Lynam
环境化学
本文中使用安捷伦SPEC C18AR固相萃取膜盘成功萃取了水中的有机氯农药残留和除草剂.使用双柱配置的GC/μECD系统进行检测,安捷伦J&W DB-35ms UI超高惰性色谱柱作为分析柱,DB-XLB色谱柱为确认柱.该方法为浓度接近或低于最大污染限值的含氯有机物提供了高度灵敏的分析方法.根据预估的分析物萃取浓度,方法使用的校准范围为1-100 ng· mL-1.分别对0.01 μg·L-1的加标水样和一个自来水水样进行了萃取和分析,结果证明可满足水中的有机氯农药残留和除草剂的测定.
关键词:
有机氯农药
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除草剂
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色谱柱
L.L.Wang
,
L.H.Zhao
,
W.Y.Hu
,
X.L.Shu
,
X.J.Yuan
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B.W.Zhang and X.Sheng Department of Applied Physics
,
Hunan University
,
Changsha 410082
,
China
金属学报(英文版)
Manuscript received 24 June 1999 The Fe Al P alloy deposits were plated on copper sheets by electroless plating. The change law of the deposition rate, composition, surface appearance and structure for the deposits was studied by changing the metallic salt ratios (AlCl 3/AlCl 3+FeSO 4), the concentration of metallic salt AlCl 3 and reductant NaH 2PO 2. The optimum plating bath was obtained. It was found that the choices of ligand and reductant were the key of increasing Al content for the deposits.
关键词:
electroless Fe Al P plating
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null
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null
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null
Min ZHAO
材料科学技术（英文）
TiB2P/Al composite was successfully fabricated by squeeze casting technology. Its mechanical and tribological properties were evaluated. The elimination of Ti-Al intermetallic compound was confirmed by X-ray diffraction (XRD) studies. At 45% volume fraction, the bending strength at ambient temperature was 934 MPa. And the fracture modes included ductile failure of Al matrix and brittle fracture of TiB2 particles. In dry sliding wear mode, severe plastic deformation and adhesive wear were found on the worn surfaces of the SiCP/Al composite. But no obvious characteristics of adhesion or abrasion wear were observed on that of the TiB2P/Al composites. At the steady stage, the friction coefficient of the SiC2P/Al composite was about 0.6. While that of TiB 2P/Al composite was only about 0.16~0.17.
关键词:
TiB2
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null
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null
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null
汪山山
,
毛昌辉
,
杨剑
,
梁秋实
,
孙波
稀有金属
doi:10.3969/j.issn.0258-7076.2012.01.029
搅拌摩擦焊的旋转速度对接头焊缝形貌、微观组织和力学性能均有较大的影响.采用搅拌摩擦焊方法对5 mm厚的(WC+ B4C)p/6063Al复合材料进行焊接试验,固定焊接速度为100 mm·min -1,旋转速度分别为900,1100,1300和1500 r·min -1,焊后观察焊缝宏观形貌和各种缺陷,并对接头的微观组织和力学性能进行了分析.焊缝宏观缺陷研究结果表明,随着旋转速度的升高,焊接热输入量增大,金属流动性得到改善,飞边、沟槽等宏观缺陷显著增多,焊缝形貌越来越粗糙；接头微观组织研究表明,由于搅拌头的搅拌作用,相比于母材,在焊核区增强相颗粒分布更加均匀,更多增强相颗粒发生破碎,且随着旋转速度的增加,这种趋势增强.对接头的抗拉强度研究表明,在1300 r·min-1以内时,随着旋转速度增加,接头抗拉强度随之增加,最大值为166 MPa,进一步增加到1500 r·min -1时,强度又有所降低,为154 MPa.
关键词:
搅拌摩擦焊
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铝基复合材料
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旋转速度
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接头组织
Journal of Materials Processing Technology
This paper has studied systematically the preparation technology and its effects on the structure and amorphous forming region (AFR), and theoretical description of the AFR for electroless Ni-P alloys. It has been found that the deposition rates increase and approach a maximum value and then decrease with the increase in the concentration of nickel chloride, sodium hypophosphite and pH value, respectively. However, the deposition rates decrease with the increase in sodium citrate. The AFR is P > 9-10 at.% in the range of concentration of nickel chloride studied. In the ran-e of concentration of sodium hypophosphite studied, there was no crystalline structure observed. The AFR calculated theoretically using the Miedema model was in good agreement with the experimental results. (C) 2002 Elsevier Science B.V. All rights reserved.
关键词:
electroless Ni-P alloys;preparation technology;structure;amorphous;forming region;Miedema model;formation enthalpies;nickel deposition;mechanism
尔延徽
,
毛昌辉
,
杨志民
,
杜军
稀有金属
doi:10.3969/j.issn.0258-7076.2007.06.008
采用8232型B-H交流回线仪对受力前后的1J79软磁合金在不同场强和频率下磁导率的变化进行了研究, 通过XRD对材料受力前后微观结构变化进行了分析. 研究表明: 场强在1～10 A·m-1范围内, 直流条件下受应力1J79合金的相对磁导率远低于不受应力1J79合金的相对磁导率; 交流条件(5～30 kHz)下受应力1J79合金的相对磁导率低于不受应力1J79合金的相对磁导率, 但低于直流条件下的降低幅度. 1J79合金受力后, 使有利于磁性能(111)晶面取向大大减少, 是合金受力后相对磁导率下降的主要原因.
关键词:
应力
,
强场
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1J79软磁合金
,
相对磁导率
