不同掺杂的钇系-123薄膜磁通特性

我们在磁场中分别测量了最佳掺杂的YBa2Cu3O7-δ、钙0．2掺杂的Y1-xCaxBa2Cu3O7-δ及钙0．5掺杂的Pr1-xCaxBa2Cu3O7-δ薄膜的电阻温度关系．利用最近Zhang et al.[Phys．Rev．B71（2005），052502]提出的热激活能的分析方法对薄膜的磁通特性进行了分析、比较与讨论．     

氩-氮混合气电感耦合等离子体在元素和同位素分析中的应用进展

在传统Ar等离子体中引入其他活性气体(如氮气等)已经成为拓展其分析性能的一种重要手段。本文较系统的阐述了Ar-N₂混合气体电感耦合等离子体的基本物理化学性质,从N₂气引入引起传统Ar-ICP基本物理化学参数变化的层面出发探讨了Ar-N₂混合气等离子体特殊性质产生的机制,回顾了Ar-N₂混合气电感耦合等离子体在质谱分析中近40年的应用成果,并且展望了该技术在未来元素和同位素分析领域的应用前景。     

Observation of Optical Second Harmonic Generation in Wet-Spun Films of Na-DNA

The observation of optical second harmonic generation (SHG) from wetspun films of Na-DNA is reported. The SHG signal is stronger at a relative humidity of 92% (corresponding to the B conformation of Na-DNA) than at low humidity of -33% (corresponding to a disordered conformation of Na-DNA). The strength of the SHG signal is also dependent on the orientation of the incident laser beam polarization with respect to the DNA helical axes.     

(La1-xCex)2/3Ca1/3MnO3体系的输运性质和反常磁特性研究

本文报告了对Ce掺杂锰氧化物(La1-xCex)2/3Ca1/3MnO3 (x=0～1.0)系列样品的输运特性和反常磁特性的研究结果.实验表明,Ce掺杂对Tc有明显的抑制作用,整体上电阻率随Ce掺杂含量增加而上升,在外加磁场时表现出极大的磁电阻效应.磁化强度随温度变化的曲线出现了两个转变,高温处对应于Mn离子磁矩的铁磁金属转变,低温处的转变则对应于Ce离子磁矩自旋有序排列的形成.表明Ce掺杂引起样品中铁磁双交换作用和反铁磁超交换作用之间的竞争,Ce离子与Mn离子有很强的相互作用.随Ce掺杂含量的增加,铁磁有序转变温度下降,而反铁磁有序转变温度则向高温处移动,铁磁区域明显减小.     

A3Ln(Ⅲ)1-xTb(Ⅲ)x(A=邻氨基苯甲酸;Ln=La、Gd、Y; x=0-0.1)稀土配合物的荧光性能

采用共沉淀法合成了掺杂 L a、 Gd、 Y的 Tb-邻氨基苯甲酸配合物 ,研究其荧光性能 ,结果显示 ,掺杂L a、Gd、Y后 ,对 Tb配合物的发光有增敏作用 ,讨论了不同的掺杂离子 (L a、Gd、Y)及掺杂量对其荧光性能的影响。发现 ,当掺杂离子取代大部分 Tb3+时 ,其发光增强仍十分显著。     

Recoil distance half-life measurements of the excited states in 145Sm

A recoil distance method was used to measure half-lives of the excited states of ₁₄₅Sm. The reaction used was ₁₃₉La(₁₀B, 4n)₁₄₅Sm. A plunger system was used. Half-lives were determined for two excited states for the first time. The yrast 27/2₊ state was found to have a half-life of 1.1 ± 0.2 ns corresponding to the retardation of 3.1 × 10₋₄ comparing with the single particle estimate of M1. The excitation energy of this state was well reproduced by the shell model calculation having a mixed configuration of [π{h^11/2(g^7/2)₋₂ (d^5/2)₋₁}¹⁰⁻, νf^7/2] + [π{h^11/2(g^7/2)₋₁}⁹⁻,νh^9/2]. Another retarded E1 transition was also found in a decay of a 21/2₊ state. Its retardation was 1.6 × 10₋₄ comparing with the single particle value. Received: 9 September 1997 / Revised version: 12 June 1998     

Pseudo-spin as a relativistic symmetry

The existence of broken pseudo-spin symmetry in the Pb nucleus has been studied in the relativistic mean field approach using realistic Lagrangian parameters. Its relationship to spin orbit splitting and the vanishingly small surface delta character of the mean spin orbit potential are investigated. In the ²⁰⁸Pb nucleus the broken pseudo-spin doublets are found to exist above the neutron (proton) Fermi surfaces. Received: 16 April 1998 / Revised version: 26 June 1998     

半导体激光系统的特殊设计

根据半导体激光器远场光束呈椭圆斑,输出功率、光谱特性、寿命、温度以及输出具有偏振性等光学特性,本文讨论了半导体激光系统的特殊设计问题。着重研讨半导体激光器输出功率的稳定,椭圆光束的准直和整圆等。     

自组装硫化铜微米管的制备及可见光催化性能

以二水合氯化铜为铜源,硫代乙酰胺为硫源,通过共沉淀法成功合成了自组装CuS微米管,该合成方法简单、反应条件温和,是合成纳米材料的一种有效方法。通过扫描电子显微镜（SEM）考察反应时间对产物形貌的影响,并初步研究其形成过程。X射线衍射（XRD）表征产物是CuS。通过改变光催化实验的条件,如催化剂的量、溶液pH值、活性橙的浓度,研究了样品在可见光下对活性橙的光催化性能。     

Beta decay of 101Sn

The β decay of the very neutron-deficient isotope ¹⁰¹Sn was studied at the GSI on-line mass separator using silicon detectors for recording charged particles and germanium detectors for γ-ray spectroscopy. Based on the β-delayed proton data the production cross-section of ¹⁰¹Sn in the ⁵⁰Cr + ⁵⁸Ni fusion-evaporation reaction was determined to be about 60nb. The half-life of ¹⁰¹Sn was measured to be 1.9(3)s. For the first time β-delayed γ-rays of ¹⁰¹Sn were tentatively identified, yielding weak evidence for a cascade of 352 and 1065keV transitions in ¹⁰¹In. The results for the ¹⁰¹Sn decay as well as those from previous work on the ¹⁰³Sn decay are discussed by comparing them to predictions obtained from shell model calculations employing a new interaction in the ⁸⁸Sr to ¹³²Sn model space.