Theory study of shapes in <Superscript>187,189</Superscript>Tl nuclei

The nuclear shapes of ^187,189Tl were investigated theoretically in this work. The total routhian surface (TRS) calculations were performed for N=106 and 108 isotopes of thallium (Z=81). The single-particle energies were obtained from the deformed Woods-Saxon potential, with the Lipkin-Nogami (LN) treatment of pairing. It is found that the collective oblate rotation coexists with the high-K prolate rotation. Superdeformed prolate rotation is included in this calculation. Supported by the National Natural Science Foundation of China (Grant Nos. 10575036 and 10675046) and the Natural Science Foundation of Zhejiang Province of China (Grant Nos. Y605476 and Y604027)     

Top-hat cw laser induced thermal mirror: a complete model for material characterization

A complete theoretical model is presented for the thermal mirror technique under top-hat laser excitation. Considering the attenuation of the top-hat excitation laser intensity along the thickness of a sample due to its optical absorption coefficient, we calculate the laser-induced temperature and surface deformation profiles. A simplified theoretical model for a high absorption sample is also developed. The center intensity of a probe beam reflected from the thermal mirror at a detector plane is derived. Numerical simulation shows that the thermal mirror under the top-hat laser excitation is as sensitive as that under Gaussian laser excitation. With top-hat laser excitation, the experimental results of thermo-physical properties of opaque samples are found to be well consistent with literature values, validating the theory.     

A new method to preserve the c-axis growth of thick YBa2Cu3O7–δ films grown by pulsed laser deposition

YBa₂Cu₃O_7–δ (YBCO) films were prepared on (1 0 0) MgO substrates by pulsed laser deposition (PLD) method. In order to eliminate the a-axis growth, which is commonly observed in the YBCO film thicker than a critical value, we developed a new PLD target that was sintered at a temperature far below YBCO 123 phase formation. The surface analysis made by AFM technique confirmed that very fine particles of around 20 nm size could be ejected from the new target to the substrate. The fine oxide clusters could be easily moved and incorporated into the YBCO phase thus benefited the c-axis growth even in the thick films. For instance, only the c-axis growth in the new film with a thickness of about 650 nm was larger than a critical thickness of the a-axis growth. However, in the standard film of the same thickness, there is 24.5% of the a-axis growth accompanying the main c-axis growth. Therefore, the c-axis growth could be preserved in the very thick YBCO film by a non-superconducting target.     

具连续变量的二阶中立型差分方程的振动性

研究一类具有连续变量的二阶中立型时滞差分方程△r^2[x（t）-cx（t-τ）=p（t）x（t-σ）的解的振动性，给出了其有界振动的几个充分条件．     

Low resistance dye-sensitized solar cells based on all-titanium substrates using wires and sheets

Low resistance dye-sensitized solar cells (DSSCs) based on all-titanium substrates were proposed in this paper. To minimize the internal resistance of DSSCs, the titanium wires and titanium sheets were used as the substrates of the photoanode and the counter electrode, respectively. Compared with the FTO substrate, titanium wires could absorb much diffused light by back reflection since the reflectivity in the titanium sheet was highly increased up to 53.12%. Furthermore, the transmittance of the front cover was increased by 13.2% using the super white glass instead of FTO substrate. The thickness of TiO₂ thin film coated on titanium wire was optimized to achieve a high cell performance. The efficiency of 5.6% for the cell was obtained with a J_sc of 15.41 mA cm⁻², V_oc of 0.59 V, and FF of 0.62. The results showed that the titanium-based DSSCs had superiority for producing the large-scale DSSCs without metal grid line.     

双面金属包覆介质波导模序数的判别方法

在双面金属包覆介质波导中 ,随着介质层厚度的变化 ,会出现TM0 模与TM1 模的分离和简并两种状态 ,从而影响衰减全反射 (ATR)谱中模序数的确认。通过对金属波导的理论分析和实验研究 ,提出了三种模序数确认方法 :本征角计算法、吸收峰全峰半宽比较法和吸收峰峰间距比较法 ,实现了两种状态下对模序数的准确判断     

二元扩散偶界面的元素扩散和金属间相的形成

根据元素扩散数据、相形成热和它们的稳定性, 分析了二元扩散偶界面元素扩散和中间相的形成.并实验研究了Ti-Ni, Nb-Sn 和Ta-Pt 三个系统. 关键词：     

广义严格对角占优矩阵新的判定准则

In this paper we provide the new criteria for a strictly generalized diagonally dominant matrix, and it proves by an example that the results of this paper extend the results in[6]. In addition, we obtain the criteria of the nonsingular M-matrix.     

一种非连续纳米氧化层自旋阀的显微结构研究

利用高分辨电子显微学方法(HREM)研究了纳米氧化层镜面反射自旋阀多层结构Ta(35nm)Ni80Fe20(2nm)Ir17Mn83(6nm)Co90Fe10(15nm)NOL1Co90Fe10(2nm)Cu(22nm)Co90Fe10(15nm)NOL2Ta(3nm).该自旋阀的巨磁电阻(GMR)效应高达15%,较无此镜面反射纳米氧化层(NOL)的自旋阀提高近1倍,同时交换偏置场亦有所增强.高分辨显微结构分析表明,介于钉扎层与被钉扎层之间的氧化层(NOL1)并未完全氧化,即除氧化过程生成的CoFe氧化物 关键词： 自旋阀 纳米氧化层 高分辨电子显微学 巨磁电阻效应     

氧气氛低温退火Pt/Ba0.8Sr0.2TiO3Pt引起的低频介电弛豫效应

研究了在不同温度区间氧气氛和氮气氛退火后处理对PtBa0.8Sr0.2TiO3Pt介电特性的影响.经过高温550℃氮气退火处理后,再放入350℃的氧气中退火,发现样品的介电特性出现了非常明显的低频弛豫现象,并且这种低频弛豫现象在350℃的氮气中退火后将会消失.通过在出现低频弛豫现象的样品的上下电极加一偏压,可以发现低频弛豫现象更加明显,并且在撤消偏压后这种增强将会逐渐减弱,直至最终恢复到偏压前的弛豫状态 关键词： 脉冲激光沉积 介电弛豫 动态随机存储器