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.     

竖直细圆管中超临界氮的对流换热研究

在内径为2mm的竖直细圆管内进行了向上流动的超临界对流换热实验。通过实验发现,质量流量、进口温度对壁面温度分布以及压降有很大影响;并讨论了换热发生增强和恶化的原因;用浮升力和热加速准则解释了其中的一些热流体现象。并基于FLUENT软件进行了数值计算,与实验结果进行比较,分析表明,数值计算预测壁面温度分布和压降有一定的适用性。     

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.     

Microstructures and properties of high Cr content coatings on inner surfaces of carbon steel tubular components prepared by a novel mechanical alloying method

In the present work, a novel mechanical alloying method was developed to prepare high Cr content coatings on the inner surface of carbon steel tubular components using a planetary ball mill. The microstructure and elemental and phase composition of mechanically alloyed coatings at different processing conditions were studied using SEM, XRD, and EDX. It showed that a proper increase in the applied milling time and the disc rotation speed favored the improvement in the thickness, surface smoothness, densification level, and microstructural homogeneity of the deposited coatings. With processing conditions optimized (rotation speed of 500 rpm and milling time of 10 h), a fully dense, 120 μm thick, high Cr content coating, consisting of metal Cr and Fe-20Cr solid solution alloy, was metallurgically bonded to the inner substrate. Comparative studies on the microhardness, corrosion resistance, and anti-oxidation capability of carbon steel substrates with and without coatings were performed. It was found that the maximum microhardness of the coating reached HV_0.1667, showing a threefold improvement upon the substrate. The coated surfaces exhibited favorable resistance against corrosion and thermal oxidation as compared with the bare substrate. Based on two important action mechanisms (i.e., friction effect and impact effect) associated with a planetary ball mill, a reasonable mechanism was presented for the formation of mechanically alloyed coatings on inner surfaces of tubular components.     

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.     

GaN/AlGaN双带红外探测及光子频率上转换研究

研究了GaN/AlGaN异质结构中的双带（中、远）红外探测及光子频率上转换特性.通过光致发光光谱确认GaN/AlGaN探测器结构中AlGaN本征层的Al组分,讨论了不同Al组分GaN/AlGaN异质结的导带带阶界面功函数差.在拟合单周期GaN/AlGaN探测器中红外和远红外波段响应谱的基础上,研究多周期GaN/AlGaN探测器与GaN/AlGaN发光二极管集成结构的中红外和远红外光子频率上转换效率与GaN发射层厚度、AlGaN本征层厚度、紫光光子出射效率、内量子效率、空间频率和发射层掺杂浓度间的关系,优化 关键词： 双带红外探测 光子频率上转换 响应谱 GaN/AlGaN     

2-(4-氟代苯甲酰基)苯甲酸-铕配合物的合成、结构表征及荧光性能的研究

以硝酸铕、2-(4-氟代苯甲酰基)苯甲酸(HL)、1,10-菲咯啉(Phen)和三苯基氧膦(TPPO)合成了EuL₃(H₂O)₆,EuL₃Phen(H₂O)₄和EuL₃(TPPO)(H₂O)₅三种固态配合物。用元素分析、红外光谱、核磁共振氢谱对配合物进行了组分确定和结构表征。IR表明,2-(4-氟代苯甲酰基)苯甲酸与Eu3+形成配合物后,位于1 692 cm-1处羧基的ν_CO峰消失,2 500～3 200 cm-1处羧基的ν_O—H峰也消失,出现了羧酸盐特有的反对称伸缩振动吸收峰(ν_as(CO-₂))和对称伸缩振动吸收峰(ν_s(CO-₂)),且Δν(ν_as(CO-₂)-ν_s(CO-₂))与钠盐的Δν相近,说明羧酸根与Eu3+以对称双齿桥式配位。在1H NMR中,形成配合物后第一配体苯环上的质子峰变为宽峰且移向高场,Phen和TPPO中质子化学位移移向低场。室温下测定了配合物的荧光激发光谱和发射光谱,激发光谱表明配合物EuL₃(H₂O)₆,EuL₃Phen(H₂O)₄和EuL₃(TPPO)(H₂O)₅的最佳激发波长分别为353.0,355.0和357.0 nm;发射光谱均显示Eu3+离子的特征发射光谱,且表明Phen对Eu3+离子的荧光发射有明显增强作用。     

物理实验课程考核、评估体系初探

对物理实验课程考核、评估方法进行了探讨，提出了物理实验课程考核、评估体系及实施细则．重点介绍了体系中的核心部分——正规的物理实验课程考试．     

双阱结构含时量子输运的微扰论及输运方程

利用Lewis-Riesenfeld不变量理论和与不变量有关的幺正变换方法研究了双阱结构含时量子 输运的微扰论.获得了双阱内含时薛定谔方程的精确解的完备集，在此基础上，把双阱与左 右热库的相互作用作为微挠，获得了双阱结构一阶近似下的输运方程，并在绝热近似下提供 了一种用于研究量子输运过程中几何相因子(Berry相因子)的方法. 关键词： 含时量子输运 输运方程 不变量 几何相因子