非晶态NdxT1-x(T=Fe,Co,Ni)薄膜的低温磁性

本文讨论了非晶态Nd_xT_1-x(T=Fe,Co,Ni)薄膜为滋结构,以及在低温下磁化强度随温度变化的反常特性,在20K附近观测到磁化强度有陡降现象,并且在较大的成份范围内所对应的温度基本不变,我们认为,在这类非晶态合金中,当Nd含量超过一定值后,其磁中性态(通称基态)可能同时是散反铁磁性和散铁磁性的共存态,在20K附近的磁化强度发生陡降,是散反铁磁性←→顺磁性相转变的反映,这两种磁结构共存的临界成份相应约为:Nd-Fe情况x≥0.45;Nd-Co,x≥0.20;Nd-Ni,x≥0.08。 关键词：     

THE STUDY OF SERS EFFECT AND ADSORPTION PROPERTY ON Cu SURFACE FOR PNBA

With different amounts of KCl added in the PNBA(p- nitro benzoic acid) aqueous solution, the factors affecting the SERS (Surface Enhanced Raman Scattering) are studied systematically on the surface of Copper. The results show that in PNBA aqueous solution the occurrence of SERS effect stongly depends on the existence of Cl^-. The amount of KCl added affects not only the emergence and the intensity of SERS effect, but also the adsorption properties such as the adsorption manner,etc.     

Y_3Fe_(5-x)Mn_xO_(12)的磁结构和磁性能

对多晶Y_3Fe_(5-x)Mn_xO_(12)(x=0.05和0.09),得到300K下的中子衍射曲线。发现当x=0.05时,Mn~(3+)离子占据16a和24d位置的几率分别为0.72和0.28;当x=0.09时,Mn~(3+)离子全部占据16a位置;还得到两种组分16a和24d位置各自的磁矩值。 在外磁场(800—10KOe)下测量Y_3Fe_(5-x)Mn_xO_(12)(x=0—0.11)的磁化曲线,温度范围是1.5—300K。得到饱和磁矩值;并利用趋近饱和定律确定1.5K下的磁晶各向异性常数k_1值,发现|K_1|值随含锰量增加而减小。     

New Spinor Field Realizations of the Non-Critical W3 String

We investigate the new spinor field realizations of the W3 algebra, making use of the fact that the W3 algebra can be linearized by the addition of a spin-1 current. We then use these new realizations to build the nilpotent Becchi-Rouet-Stora-Tyutin charges of the spinor non-critical W3 string.     

Tb1-xGdxFe2的磁矩和矫顽力

测量了赝二元立方Laves相化合物TbGdFe₂(0≤x≤1)的磁化曲线、居里温度和矫顽力随温度的变化。发现化合物由TbFe₂向GdFe₂过渡时,样品的饱和磁化强度几乎直线下降。在所有成分下,Fe原子的磁矩都是常数(μ_Fe=1.60±0.04μ_B),但Tb原子的磁矩,由于受晶场影响,却小于自由离子的值(gJ=9.Oμ_B)。矫顽力由两部分组成:一为畴壁受Peierls势垒和稀土 关键词：     

布里渊散射研究In-BCVIG单晶的体磁振子和偶极——交换磁振子

布里渊散射研究Ｉｎ－ＢＣＶＩＧ单晶的体磁振子和偶极——交换磁振子刘玉龙张昊朱恪（中国科学院物理研究所北京１０００８０）萧季驹李泽民（香港城市大学物理及材料科学系香港九龙）ＭａｇｎｏｎＬｉｇｈｔＳｃａｔｅｒｉｎｇｆｒｏｍＩｎ－ＢＣＶＩＧＳｉｎｇｌｅＣｒ...     

用同位素替代方法识别化合物ABPO_5(A=Ca,Sr,Ba)的内振动模

用同位素替代方法识别化合物ＡＢＰＯ５（Ａ＝Ｃａ，Ｓｒ，Ｂａ）的内振动模张昊施颖朱恪刘玉龙刘竟青赵铁男梁敬魁（中国科学院物理研究所北京１０００８０）ＶｉｂｒａｔｉｏｎａｌＳｐｅｃｔｒｏｓｃｏｐｙＳｔｕｄｉｅｓｏｆＩｎｔｅｒｎａｌＭｏｄｅｓｏｆＳｔｉｌｗ...     

Determination of elastic, piezoelectric, and dielectric constants of an R:BaTiO3 single crystal by Brillouin scattering

From the sound velocity measured using the Brillouin scattering technique, the elastic, piezoelectric, and dielectric constants of a high-quality monodomain tetragonal Rh：BaTiO3 single crystal are determined at room temperature. The elastic constants are in fairly good agreement with those of the BaTiO3 single crystal, measured previously by Brillouin scattering and the low-frequency equivalent circuit methods. However, their electromeehanical properties are significantly different. Based on the sound propagation equations and these results, the directional dependence of the compressional modulus and the shear modulus of Rh：BaTiO3 in the （010） plane is investigated. Some properties of sound propagation and electromechanical coupling in the crystal are discussed.     

神龙一号直线感应加速器X光转换靶破坏诊断北大核心CSCD

利用能量约450 keV、焦斑直径1~4 mm的低能X光对神龙一号直线感应加速器束靶作用后钽靶的破坏进行诊断,利用增强型电荷耦合器件（ICCD）对诊断过程记录,得到束靶作用后数μs时间内钽靶材料密度的变化。结果表明：在束靶作用后约1μs内靶材料密度基本没有变化,且该时间段内ICCD相机没有观察到有靶前钽靶材料的微粒喷射。     

大面积投影式太阳模拟器的光学设计EI北大核心CSCD

为模拟大面积空间太阳光辐照环境,提出一种新型投影式太阳模拟系统设计方法。根据光学扩展量理论分析系统的能量传递过程,采用4个短弧氙灯阵列作为光源,设计物方远心投影系统以实现大面积均匀照明。通过Zemax软件模拟仿真及实际系统测量来验证系统设计的合理性。实验结果表明:太阳模拟器的有效辐照面尺寸为1000mm×1000mm,辐照度可达1263W/m^2,且辐照面不均匀度优于±4.82%。该研究可为卫星载荷的空间环境实验提供准确可靠的太阳光辐照,弥补传统大型太阳模拟器体积大、造价高的局限。