氮气在100 eV以下的绝对振子强度密度

在入射电子能量为2500 eV、能量分辨为100 meV的条件下，得到了氮气在100 eV以下的绝对光学振子强度密度和广义振子强度密度；得到了23 eV和31.4 eV两个超激发态的绝对广义振子强度、并讨论了它们的动量转移依赖特性。     

氦原子光学振子强度的高分辨dipole(e,e)研究

利用高分辨快电子能量损失谱仪,采用高分辨的dipole(e,e)方法对氦原子的光学振子强度进行了研究.它避免了光学测量中的困难,提高了实验精度.在21～26 eV的能量损失范围内测量得到了氦的I¹S→n¹P中跃迁以及电离过程的光学振子强度谱,并在59～67eV和 69～74eV的能量损失范围内对氦的自电离共振过程的光学振子强度谱进行了研究,所得结果与前人的工作进行了比较.     

在时域实验研究扩散诱导的Ramsey压窄

基于Duan-Lukin-Cirac-Zoller(DLCZ)方案,在时域上研究了扩散诱导的Ramsey压窄.以87Rb热原子系综为研究对象,观测到缓冲气体,激光束尺寸和镀石蜡Rb池均可以导致Ramsey压窄现象.实验结果和文献中重复相互作用模型预期的一致.     

Numerical Analysis of Alternating-Current Small-Signal Response in Graphene Nanoribbons

Alternating-current small-signal admittances of armchair graphene nanoribbons are investigated using the method of non-equilibrium Green＇s function. The calculated ac admittances show an oscillatory response between inductive and capacitive behaviors, which is a result of the finite length of the graphene nanoribbon. The effects of hydrogen-passivated edges on ac response are demonstrated. At low frequency, the edge effects transform the inductive behavior in a metallic graphene nanoribbon into a capacitive one. Finally, the effects of variations in the width and bandgap of a graphene nanoribbon on its dynamic response are investigated.     

1D atom localization via probe absorption spectrum in a four-level cascade-type atomic system

We present a simple scheme of atom localization in a subwavelength domain via manipulation of probe absorption spectrum in a four-level atomic system. Due to the joint quantum interference induced by the standing-wave and radio-frequency driving fields, the localization peak position and number as well as the conditional position probability can be controlled by properly adjusting the system parameters. The proposed scheme may provide a promising way to achieve high-precision and high-resolution 1D atom localization.     

Selecting optimal selling format of a product in B2C online auctions with boundedly rational customers

The advancement of Internet technology has enabled new formats for selling products in the B2C online auctions. At present, on the major online auction sites, there exist three popular selling formats, namely, the posted price, pure auction and buy-price auction formats. It is an important decision problem for a firm to select the most profitable format to sell its products through the Internet. The customer behavior is of course a crucial element of the decision process. To the best of our knowledge, most models available today assume that customers are perfectly rational. To better understand the decision process, in this paper, we incorporate the concept of bounded rationality into consideration. We first present a “behavior choice function” to characterize the behavior of the customers with bounded rationality. Then corresponding to each selling format, we construct a revenue model based on the bounded rationality for analysis. Finally, we conduct some elaborate computational experiments to investigate the performance of each revenue model for developing new managerial insights. Our computational results clearly demonstrate how the bounded rationality of customer behavior affects the choice of a preferable selling format for a B2C firm in an online auction.     

Sr2SiO4∶Dy3+材料制备及发光特性

采用高温固相法制备了Sr2SiO4∶Dy3+发光材料. 在365 nm紫外光激发下, 测得Sr2SiO4∶Dy3+材料的发射光谱为一个多峰宽谱, 主峰分别为486, 575和665 nm; 监测575 nm的发射峰, 所得材料的激发光谱为一个多峰宽谱, 主峰分别为331, 361, 371, 397, 435, 461和478 nm. 研究了Dy3+掺杂浓度对Sr2SiO4∶Dy3+材料发射光谱强度的影响. 研究结果显示, 随着Dy3+浓度的增大, 黄、蓝发射峰比值(Y/B)也逐渐增大; 随着Dy3+浓度的增大, 575 nm发射峰强度先增大后减小. 加入电荷补偿剂Li+, Na+和K+均提高了Sr2SiO4∶Dy3+材料的发射光谱强度, 其中以Li+的情况最为明显.     

Synthesis and insecticidal evaluation of tetrahydroimidazo[1,2-a]pyridin-5(1H)-one derivatives

A series of novel tetrahydroimidazo[1,2-a]pyridine-5(1H)-one derivatives containing a electronegative pharmacophore(=CNO₂) were synthesized via practical aza-ene reaction and characterized by ¹H NMR, ¹³C NMR, ¹⁹F NMR and HRMS. Preliminary bioassays showed that some of the target compounds exhibited good insecticidal activity against brown planthopper(Nilaparvata lugens) and cowpea aphids(Aphis craccivora) at 500 mg L^-1. Among them, compound 11h was active against brown planthopper at 100 mg L^-1. The insecticidal activities varied significantly depending on the types and patterns of the substituents, which provided guidance for further investigation on structure modifications.     

新型层柱材料Zn2Al-SiW9M3的合成、表征及催化性能研究

杂多阴离子柱撑粘土是一类新型层柱催化材料.本文采用水热合成与离子交换方法首次将三取代Keggin结构杂多阴离子α-[SiW9O37M3(H2O)3]n-(简写为SiW9M3,M＝Mn2+,Cr3+,Ti3+,Fe3+)嵌入到Zn-Al型阴离子粘土层间,并通过XRD、IR、DTA和元素分析等手段对其结构进行了表征,考察了它们在顺丁烯二酸环氧化反应中的催化活性.     

十二烷基硫酸钠多相微乳液的研究

十二烷基硫酸钠(SDS)/正丁醇-异丙醇/庚烷/盐水体系可形成多相微乳液,研究了盐浓度、温度对相态的影响,并用小角X衍射、NMR和ESR技术对多相微乳液的结构进行了研究,比较了四相微乳液中两个富表活剂相的区别。结果认为该体系在合适条件下可形成三相及四相微乳液,微乳液中伴随有层状液晶存在。四相微乳液中的两个富表活剂相组成及结构均不同,表现为ESR中TEMPO探针所检测到的微环境不同,以及^2HNMR反映出其组成和H~2O分子所在位置处分子平均有序性也不同。