磁性离子Fe和Ni替代YBCO体系的结构特征和载流子局域化

为阐明磁性离子在不同替代位置对YBCO体系超导电性的影响机制，利用正电子湮没及相关实验手段结合数值模拟，系统研究了Fe和Ni掺杂的YBa₂Cu₃O_7-δ体系. 结果表明，Fe和Ni离子在替代过程中均以离子团簇的形式进入晶格. 当离子进入CuO₂面时，由于团簇改变了周围的电子结构，造成电子的局域化，并直接影响了电子对的配对和输运，因而强烈抑制了体系的超导电性.而当掺杂离子进入Cu-O链区时，它们同样通过团簇的形式改变周围 关键词： YBCO超导体 磁性离子替代 正电子湮没 数值模拟     

Yb∶YAG晶体的晶胞参量及Yb~(3+)分凝系数的研究

应用提拉法生长出不同Yb3+ 浓度的Yb3xY3( 1-x) Al5O12 晶体 Yb3+ 离子的分凝系数 1是 1 .0 8±0 .0 1 ,与Yb3+ 离子掺杂浓度无关 研究了Yb3xY3( 1-x) Al5O12 晶体的晶胞参量 ,推导出联系晶胞参量、密度与Yb3+ 离子掺杂浓度的关系方程式     

Condorcet Winners for Public Goods

In this work, we consider a public facility allocation problem decided through a voting process under the majority rule. A location of the public facility is a majority rule winner if there is no other location in the network where more than half of the voters would have been closer to than the majority rule winner. We develop fast algorithms for interesting cases with nice combinatorial structures. We show that the computing problem and the decision problem in the general case, where the number of public facilities is more than one and is considered part of the input size, are all NP-hard. Finally, we discuss majority rule decision making for related models.     

Low-Threshold Random Laser with One Mirror and Feedbacks in PMMA Nano-Composite Films

A low-threshold random laser with one mirror and feedback is investigated in the PMMA film containing rhodamine 590 and TiO2 nano-particles. Incoherent and coherent laser emission is observed. Effect of particle concentration on light emission is explored, and the optimum particle concentration is obtained. Optical microscopy and scanning probe microscopy are used to investigate the film structure, and the principle of incoherent and coherent laser is analysed.     

含O=P—N基环膦二肽的结构研究

分离出环膦二肽的几何异构体。用高分辩~H NMR结合其它光谱确定了异构体的数目,用X射线确定了它们的立体结构,发现磷上苯环与其α-碳上取代基互为顺式,六元环采用扭船式构象。     

一种新的高聚物酶联免疫印迹法的建立及其在乙肝表面抗原检测中的应用

聚(N—异丙基丙烯酰胺)(PNIP)于室温下是一种水溶性聚合物。这个聚合物的水溶液在32℃左右,在一个宽的浓度范围内(可高达5％)具有下部临界会溶温度(LCST)。在研究中我们发现,PNIP和PNIP与酶标抗体的复合物可以快速紧密地吸附到醋酸、硝酸纤维素膜上。利用PNIP在纤维素膜上的高保留率的特性,我们建立了一种新的免疫分析方法:聚合物酶联免疫印迹法。该法简单、快速、特异性高,能检测到人血清中10ng/ml的乙肝表面抗原。     

趋磁细菌研究Ⅲ．琥珀酸脱氢酶、呼吸抑制剂、解偶联剂对WD－1生长与磁小体合成的影响

报道了趋磁细菌ＷＤ－１琥珀酸脱氢酶、呼吸抑制剂ＮａＮ３、解偶联剂ＤＮＰ对磁小体合成的影响．琥珀酸脱氢酶活性高，磁小体合成能力强，每个细胞所含磁小体数量多；１ｍｍｏｌＬ－１ＮａＮ３或１ｍｍｏｌＬ－１ＤＮＰ能抑制ＷＤ－１的好氧生长，１０ｍｍｏｌＬ－１ＮａＮ３不抑制ＷＤ－１的微好氧生长，但１ｍｍｏｌＬ－１ＤＮＰ明显地影响微好氧生长，即生长缓慢．ＷＤ－１在微好氧、好氧、好氧与０．０１～０．１０ｍｍｏｌＬ－１ＮａＮ３（或ＤＮＰ）的培养条件下生长时，磁小体合成能力依次下降     

Approximate methods for analyzing the growth of large cracks in fatigue damaged aircraft sheet material and lap joints

Several levels of approximation are investigated to account for the effect of small fatigue cracks on the residual strength of aircraft sheet materials and fuselage lap joints containing major cracks. A version of the Dugdale model is proposed which accounts for strain hardening of the sheet in an approximate way and which incorporates a criterion for crack advance leading to crack growth resistance. This model builds upon the model proposed by Nilsson and Hutchinson [1] and accounts for the detailed interaction between the major crack and the small damage cracks. A simpler version of the model uses the damage-reduced local strength of the sheet or joint in assessing the effect of the major crack on residual strength. The simpler approach thus bypasses the necessity of a direct determination of the highly complicated details of the interaction of the small cracks in a lap joint with a major crack.     

表示张量积与量子对称

利用量子对称群的概念，我们给出Ｕ＿ｑ（ｓｌ＿ｎ）－多项式、Ｕ＿ｑ（ｓｌ＿ｎ）－外积的定义，说明Ｕ＿ｑ（ｓｌ＿ｎ）的ｑ－振子、ｑ－旋量表示不过是Ｕ＿ｑ（ｓｌ＿ｎ）标准表示的量子对称、量子反称张量积，这和经典情形是一致的。     

Co（Ⅱ）,Ni（Ⅱ）非有机溶剂液—液萃取行为的研究

In PEG-Eriochrome cyanine R-(NH4)2SO4 system the liquid-liquid extraction behaviour of Co(II) and Ni(II) without organic solvents was investigated. We found that Ni(II) was almost extracted by PEG phase while Co(II) was not extracted in the water solutions of NaAc-HAc (pH=5) and (NH4)2SO4. Thus Co(II) was quantitatively separated from mixed solutions of Ni(II) and Co(II) ions.