A.Y. Deng
,
G.L. Jia
,
J.C. He
金属学报(英文版)
The three-dimensional electromagnetic characteristics and non-uniform distribution of electromagnetic field in soft-contact mold have been analyzed by numerical simulation. The results show that the maximum electromagnetic flux density is found in front of slit; the electromagnetic flux density becomes large as coil current and slit number increase. In a certain frequency range, the electromagnetic flux density increases with increasing frequency; and the frequency range is different with changing of azimuthal position along inner wall of mold. The uniformity of electromagnetic field is effected mainly by frequency and mold structure parameters. Increasing slit number and adjusting slit arrangement position can improve the electromagnetic flux density and the uniformity of electromagnetic field. For a soft-contact mold with 16 slits, when frequency is 20kHz, the optimal slit arrangement parameter is a: b = 1: 2.c＝0.
关键词:
continuous casting
,
null
,
null
X.Q. Bai
,
J.C. He
金属学报(英文版)
The coagulation time and position of micro-sized non-metallic inclusions in molten metal during ultrasonic separation process were investigated, and the motion course of micro-sized non-metallic inclusions in an ultrasonic standing wave field was numerically simulated. The results of theoretical analysis and numerical simulation show that the movement of inclusions depends on the balance between the acoustic radiation force, effective buoyancy force and viscous drag force. It is presented that micro-sized inclusions, agglomerated at antinode-planes may be removed further with horizon tal ultrasound.
关键词:
ultrasound
,
null
,
null
,
null
,
null
A.Y. Deng
,
J.C. He
金属学报(英文版)
A coupled model including electromagnetic field, fluid dynamic, heat transfer and so-lidification, is developed and applied to the numerical simulation of steel flow andsolidification in a 100mm× 100mm soft-contact mold. In this study, the 3D finite dif-ference method and n, on-staggered grid system for fluid flow with body fitted coordinatewere employed. Numerical results show that the electromagnetic force mainly affectsthe steel flow at upper part of mold, especially in the vicinity of meniscus. There existupward flows covering the surfaces of the billet due to the concentration of electro-magnetic force on the upper part of the billet. This flows join together and form adownward flow near the SEN, so a distinct circulating flow zone is formed at upperpart of mold. After applying electromagnetic force, the steel velocity is improved andthe temperature is raised. The strong stirring of electromagnetic force on liquid steelmakes the kinetic energy on free surface increase. It is clearly seen that the solidifi-cation start point shifts downward in soft contact mold. As a result, the initial shellthickness gets thin and the initial solidification shell length is shortened.
关键词:
continuous casting
,
null
,
null
,
null
,
null
G.J. Xu
,
D.H. Li
,
J.C. He
金属学报(英文版)
In order to know the distribution of magnetic field in a novel flow control of mold(NFC Mold) and to provide the experimental data for the electromagnetic structuredesign and the analysis of flow control in continuous casting mold, the magnetic fieldin a NFC Mold were measured by Tesla meter of Model CT-3. The method of vectorsynthesis was adopted in the measurement of magnetic fields. The results showed thatthe magnetic field in the NFC Mold was composed of two main magnetic areas thatwere symmetrical. Although there was leaking magnetic flux between the lower surfaceof the upper pole and the upper surface of the lower pole on the sides, it was restrainedby the main magnetic fields effectively. Therefore the NFC Mold was more preferablysatisfied to be used in controlling the molten steel flow in continuous casting mold.
关键词:
continuous casting
,
null
,
null
,
null
S.C. Fan
,
B.K. Li
,
J.C. He
金属学报(英文版)
A mathematical model has been developed to analyze the flow patterns and subsurface trajectories of spherical shaped particles (alloy additions) in gas stirring ladles. First,a numerical method to solve fluid flow problems in conjunction with a curvilinear coordinate system is proposed. The internal boundary in flow field, which must be designated in the cylindrical polar coordinate system, can be avoided by using bodyfitted coordinate system (BFC). Consequently, computed flow of molten steel and paths of alloying additions are able to cross smoothly the geometric centerline of cylindrical vessel. Second, motion of particles is calculated in the three-dimensional coordinate system, the modification of parameters, such as the drag coefficient and density in the gas plume region, is examined. When the density of sphere is closer and closer to that of fluid, the path of motion is longer and longer. If the plug is moved off-centered to the half of radius, the path of sphere is prolonged, and the sphere may go through the geometric centerline of vessel, reach the deeper region. The immersed depths increase with increasing entry velocities.
关键词:
alloying addition
,
null
,
null
向鑫陈长安刘柯钊罗丽珠刘婷婷王小英
金属学报
doi:DOI:10.3724/SP.J.1037.2009.00590
用离子注入技术实现了Al表面C元素的掺杂, 并利用XPS, XRD, TEM和SEM研究了C掺杂对Al中离子
注入He行为的影响. 结果表明, 掺杂的C在Al表面形成了Al4C3, 随着C掺杂量的增加, Al表面组织的择优取向
和晶胞体积发生改变, 从而影响了Al中的He离子注入行为. 预先掺杂的C对He离子注入Al表面的鼓泡行为有重
要影响, 其影响程度与掺杂剂量有关. 小剂量C掺杂后, 能有效抑制鼓泡的长大, 并使Al表面鼓泡均匀分布; 更高
剂量C掺杂后, C对表面鼓泡的抑制作用减弱, 甚至加剧He离子的辐照损伤, Al表面出现孔洞和剥落现象. 掺杂的
C对Al基体的微观结构也有很大影响.
关键词:
Al
,
C doping
,
He behavior
,
blistering
,
microstructure
向鑫
,
陈长安
,
刘柯钊
,
罗丽珠
,
刘婷婷
,
王小英
金属学报
doi:10.3724/SP.J.1037.2009.00590
用离子注入技术实现了Al表面C元素的掺杂,并利用XPS,XRD,TEM和SEM研究了C掺杂对Al中离子注入He行为的影响.结果表明,掺杂的C在Al表面形成了Al_4C_3,随着C掺杂量的增加,Al表面组织的择优取向和晶胞体积发生改变,从而影响了Al中的He离子注入行为,预先掺杂的C对He离子注入Al表面的鼓泡行为有重要影响,其影响程度与掺杂剂量有关,小剂量C掺杂后,能有效抑制鼓泡的长大,并使Al表面鼓泡均匀分布;更高剂量C掺杂后,C对表面鼓泡的抑制作用减弱,甚至加剧He离子的辐照损伤,Al表面出现孔洞和剥落现象,掺杂的C对Al基体的微观结构也有很大影响,
关键词:
Al
,
C掺杂
,
He行为
,
鼓泡
,
微观结构
向鑫
,
陈长安
,
蒋春丽
稀有金属材料与工程
用离子注入技术实现了Al表面Fe、C元素的掺杂,并用XRD研究Fe、C掺杂对He离子注入Al表面晶格畸变的影响.结果发现,预先掺杂的Fe、C在Al表面的晶格畸变中扮演重要角色,且影响程度与掺杂剂量有关.随着预先掺杂Fe剂量的增大,Al表面晶格畸变量先减小后增加,表明小剂量的Fe掺杂有助于降低He离子注入引起的晶格畸变.C掺杂后能进一步降低预先掺杂Fe引起的晶格畸变,降低程度随C剂量的增加而增加.可见,小剂量的Fe和高剂量的C共掺杂能有效降低He离子注入后Al表面的品格畸变.
关键词:
Al
,
XRD
,
Fe、C掺杂
,
晶格畸变
姜志进
原子核物理评论
在核吸收与随动者吸收理论的基础上,给出了在有QGP相变情况下高能重离子碰撞中的J/Ψ微分产生截面,并用其讨论了CERN的NA50合作组给出的入射动量为158 AGeV/c的Pb-Pb碰撞中的J/Ψ反常抑制现象。理论较好地解释了实验结果。
关键词:
J/Ψ反常抑制
,
核吸收
,
随动者
吉日木图
原子核物理评论
研究自旋和轨道量子数不同的介子之间的质量劈裂对检验夸克势模型非常重要.在以往的夸克势模型计算中,η_c-J/ψ的质量劈裂都很难达到实验的值.用正规化形状因μ~2/(q~2+μ~2),在对完整的动量空间中的Breit夸克势实施一次正规化下研究了η_c-J/ψ和新介子ηb与Υ(1s)之间的质量劈裂.结果表明,正规化形状因子中的屏蔽质量μ应与介子折合质量有关,当将其展开为介子折合质量的三阶多项式时,上述介子质量劈裂可以精确重现实验的结果.另外,由于完整的Breit 势包含有自旋一轨道耦合相互作用的项,因而还可以研究χ_(c0),χ_(c1)和χ_(c2)之间的质量劈裂.
关键词:
夸克势模型
,
矩阵元
,
介子束缚态
,
正规化
,
质量劈裂
