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Search Results: 1 - 10 of 101959 matches for " 郝延明 "
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A CALCULATION OF THE EXCHANGE INTERACTION CONSTANT BETWEEN THE R-SUBLATTICE AND THE 3d-SUBLATTICE IN R2Fe17-xAlx COMPOUNDS
R2Fe17-xAlx化合物中R-T交换耦合常量的计算

HAO YAN-MING,

物理学报 , 2000,
Abstract: A calculation of the exchange interaction constant between the R moment and the T moment in rare-earth (R) transition-metal (T) compounds of the type R2Fe17 has been discussed using molecular field theory combining with the results of neutron diffraction or X-ray diffraction. The calculated values for R2Fe17-xAlx (R=Tb,Dy,Ho,Er and Gd,x=7,8) have been given and they are in agreement with the experimental results .
Y_2Fe_(15)Al_2化合物的反常热膨胀及本征磁致伸缩(英文)
,安力群,郭娟,吕昆
硅酸盐学报 , 2009,
Abstract: 通过X射线衍射及磁测量手段研究了Y2Fe15Al2化合物的结构及磁学性质。结果表明Y2Fe15Al2化合物具有六角相的Th2Ni17型结构。X射线热膨胀测量表明在363~466K的温度范围内,Y2Fe15Al2化合物出现负热膨胀现象,其平均热膨胀系数为α=-2.45×10-5/K。通过比较实际测量得到的晶格参数和外延计算得到的顺磁态的晶格参数之间的差别,在282~466K的温度区间内计算了化合物的本征磁致伸缩系数。结果表明化合物的本征体磁致伸缩随着温度的升高从282K时的11.3×10-3下降到466K时的接近于零;化合物沿c轴方向和基面内的本征线磁致伸缩都随着温度的升高而下降,并且在400K以下沿c轴方向的本征线磁致伸缩比基面内的本征线磁致伸缩大,这表明沿c轴方向的磁弹耦合强度高于基面内的磁弹耦合强度。
y2al3fe11mn3化合物的负热膨胀
,王博文,高艳
材料研究学报 , 2002,
Abstract: ?利用x射线衍射及磁测量手段研究了y2al3fe14-xmnx系列化合物的结构。结果表明,该系列化合物具有th2ni17型结构;随着x的增加,化合物的单胞体积呈现非线性的变化,这表明在化合物的磁相变点附近存在较大的正的本征磁致伸缩。对y2al3fe11mn3化合物进行的变温x射线衍射研究表明,该化合物在其居里点附近(185k-200k)具有负热膨胀性质,其热膨胀系数为-7.5?10-5/k。
nd2co17-xmnx化合物的结构与磁性
,崔春翔,孟凡彬
材料研究学报 , 2002,
Abstract: ?研究了nd2co17-xmnx(x=0,1,3,5,7,9,11)化合物的结构和磁性。nd2co17-xmnx化合物具有菱方相th2zn17型结构;在x比较小时,随着x的增加,化合物的单胞体积缓慢增大,而在x比较大时,随着x的增加,化合物的单胞体积迅速增大,这表明nd2co17-xmnx化合物在磁性状态下存在着正的自发体磁致伸缩;随着x的增加,化合物的居里点及4.2k下的饱和磁化强度都快速下降,这表明在x比较小时,3d次晶格的co-co之间的铁磁交换作用起主导作用,而在x比较大时,3d次晶格中反铁磁交换作用起主要作用;在约234k观察到了nd2co14mn3化合物的自旋重取向现象。
Structure and Curie temperature of Y2(Fe1-x-y,Coy,Crx)17 compounds
Y2(Fe1-x-y,Coy,Crx)17化合 物的结构及居里温度

Hao Yan-Ming,Zhao Wei,Gao Yan,
,赵 伟,高 艳

物理学报 , 2003,
Abstract: The structure and Curie temperature of Y2(Fe1-x-y,Coy ,Crx)17 c ompounds have been investigated by means of x_ray diffraction and magnetization measurement. The Y2(Fe1-x-y,Coy,Crx) 17 compounds have a hexago nal Th2Ni17_type structure. With increasing x, the unit_ce ll volumes of Y2Fe17-xCrx and Y2CoFe16-xCrx compounds have a small decreas e initially, followed by a greater decrease. It is proved that the magnetic inte raction of Fe atoms at 4f sites of Y2Fe17 compound is anti ferromagnetic by studying the variation of Curie temperature of Y2(Fe1-x-y,Coy,Crx )17 compounds. The result also shows that a few Co and Cr atoms subst ituti ng for Fe atoms can enhance Curie temperature of Y2(Fe1-x-y,Coy,Crx)17 obviously.
Spontaneous magnetostriction of Tb2Fe15.5Cr1.5 compound
Tb2Fe15.5Cr1.5化合物的本征磁致伸缩

Hao Yan-Ming,Zhou Yan,Zhao Miao,
,周 严,赵 淼

物理学报 , 2005,
Abstract: 通过x射线衍射及磁测量手段研究了Tb2Fe15.5Cr1.5化 合物的热膨胀性质及本征磁致伸缩性质.研究结果表明Tb2Fe15.5Cr 1.5化合物在293—672K的温度范围内具有六角相的Th2Ni17型结构.在432—522K的温度范围内具有负热膨胀 性质,其平均热膨胀系数=-157×10-5/K.对本征磁致伸缩的研究结果表明Tb2Fe15.5Cr1.5化合物中存在着较强的各向异性的本 征磁致伸缩,293K时其本征体磁致伸缩约为84×10-3,晶格畸变主要发生在c 轴方向上.磁测量研究结果表明Tb2Fe15.5Cr1.5化合物的居里温度约为494K,比其母 合金Tb2Fe17高约80K.
Spontaneous magnetostriction of Y2Fe16Al compound
Hao Yan-Ming,Zhao Miao,Zhou Yan,
,赵淼,周严

中国物理 B , 2005,
Abstract: The structure and magnetic properties of Y2Fe16Al compound have been investigated by means of x-ray diffraction and magnetization measurements. The Y2Fe Fe16Al compound has a hexagonal Th$_{2}$Ni$_{17}$-type structure. Negative thermal expansion was found in Y2Fe16Al compound in the temperature range from 332 to 438K by x-ray dilatometry. The coefficient of the average thermal expansion is \alpha =-3.4\times 10-5K-1. The spontaneous magnetostrictive deformations from 293 to 427K have been calculated based on the differences between the experimental values of the lattice parameters and the corresponding values extrapolated from the paramagnetic range. The result shows that the spontaneous volume magnetostrictive deformation \textit{$\omega $}$_{\rm S}$ decreases from 5.4$\times $10-3to near zero with temperature increasing from 293 to 427K, the spontaneous linear magnetostrictive deformation \textit{$\lambda $}$_{\rm c}$ along the $c$ axis is much larger than the spontaneous linear magnetostrictive deformation \textit{$\lambda $}$_{\rm a}$ in basal-plane in the same temperature range except near 427K.
Spontaneous magnetostriction of Dy2 AlFe13 Mn3 compound
Dy2 AlFe13 Mn3 化合物的本征磁致伸缩

Hao Yan-Ming,Zhou Yan,Zhao Miao,
,周严,赵淼

中国物理 B , 2005,
Abstract: The structural and magnetic properties of Dy$_{2}$AlFe$_{13}$Mn$_{3}$compound have been investigated by means of x-ray diffraction and magnetization measurements. The Dy$_{2}$AlFe$_{13}$Mn$_{3}$ compound has a hexagonal Th$_{2}$Ni$_{17}$-type structure. Negative thermal expansion is found in the Dy$_{2}$AlFe$_{13}$Mn$_{3}$ compound at the temperatures ranging from 245 to 344K by x-ray dilatometry. The coefficient of the average thermal expansion is $\overline \alpha =-1.1\times 10^{-4}$K$^{-1}$. The spontaneous magnetostrictive deformations in the 105--360K temperature range have been calculated by means of the differences between the experimental values of the lattice parameters and the corresponding values extrapolated from the paramagnetic range. The result shows that the spontaneous volume magnetostrictive deformation \textit{$\omega $}$_{\rm s}$ increases from 7.0$\times $10$^{-3}$ at 105K to 9.1$\times $10$^{-3}$ at 245K, and then decreases with the temperature increasing. The spontaneous linear magnetostrictive deformation $\la_{c}$ along the $c$ axis decreases as temperature increases. The spontaneous linear magnetostrictive deformation $\la_{a}$ in basal-plane increases from 0.8$\times $10$^{-3}$ at 105K to 3.4$\times $10$^{-3}$ at 270K, and then decreases with the temperature increasing further.
固相微萃取-脉冲火焰光度法测定大气及水中的路易氏剂
王红英,,王秀凤,
分析化学 , 2005,
Abstract: 建立了固相微萃取(SPME)与气相色谱/脉冲火焰光度检测器(GC/PFPD)联用测定大气和水中路易氏剂及其水解产物的方法。探讨了影响SPME萃取效率的萃取头类型、萃取时间、解吸时间等因素。优化了PFPD的条件参数、衍生化试剂及衍生条件。在优化的条件下,路易氏剂衍生产物的响应值与浓度有良好的线性关系。本方法对水中路易氏剂及其水解产物的检出限为0.1μg/L;气体中路易氏剂的检出限为10ng/m3;水样的加标回收率为96.7%~102.1%;气体样品的加标回收率为94.9%~103.0%;RSD为2.06%。
低渗气藏气体渗流滑脱效应影响研究
朱光亚,刘先贵,李树铁,,
天然气工业 , 2007,
Abstract: ?低渗透气藏储层致密、渗透率极低、以微孔道为主,当气体在低渗孔隙介质中低速渗流时,气体渗流的主要物理特征是具有“滑脱效应”。为此,研究了具有滑脱效应的储层渗透率界限以及孔隙压力条件。通过对苏里格气田32块低渗岩心样品所进行的实验,探讨了低渗气藏天然气渗流规律。研究表明,当努森数介于0.1~1时,气体渗流不遵从克氏方程。实验结果还表明:克氏系数随储层渗透率的增大而减小,当储层渗透率大于0.1×10-3μm2时,气体滑脱效应可以忽略不计;克氏系数随平均孔隙压力的增大而减小,当孔隙压力大于1.5mpa时,气体滑脱效应也可以忽略不计。
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