F-P腔内自旋轨道耦合玻色-爱因斯坦凝聚体的色散研究

计算分析了处于单模Fabry-Pérot腔内的无相互作用玻色-爱因斯坦凝聚体在引入自旋轨道耦合作用下的色散关系. F-P腔为冷原子系统提供了量子化的光晶格,利用紧束缚近似和平均场近似进行二次量子化,选取合适的腔参数得到单原子缀饰态能级的具体表达式.两束弱的Raman激光和外加磁场作用于玻色-爱因斯坦凝聚体,实现了有效的自旋轨道耦合,提供了一个人工规范势,使玻色-爱因斯坦凝聚体中产生了沿腔轴方向一维的高度可控的狄拉克点.     

Electrohydrodynamic behaviors of droplet under a uniform direct current electric field

The electrohydrodynamic behaviors and evolution processes of silicone oil droplet in castor oil under uniform direct current(DC)electric field are visually observed based on a high-speed microscopic platform.Subsequently,the effects of different working conditions,such as electric field strength,droplet size,etc.,on droplet behaviors are roundly discussed.It can be found that there are four droplet behavior modes,including Taylor deformation,typical oblique rotation,periodic oscillation,and fracture,which change with the increase of electric field strength.It is also demonstrated that the degree of flat ellipse deformation gets larger under a stronger electric field.Moreover,both of the stronger electric field and smaller droplet size lead to an increase in the rotation angle of the droplet.     

Highly chemoselective lipase from Candida sp. 99-125 catalyzed ring-opening polymerization for direct synthesis of thiol-terminated poly(ε-caprolactone)

Lipase from Candida sp. 99-125 catalyzed ring-opening polymerization of ε-caprolactone in the presence of 6-mercapto-1-hexanol was presented as a new metal-free approach for direct synthesis of welldefined thiol-terminated poly(ε-caprolactone). Remarkably, high chemoselectivity of lipase from Candida sp. 99-125 toward hydroxyl and thiol was exhibited and quantitative thiol fidelity over 90% was achieved. The tedious protecting/deprotecting steps for thiol and metal residue were avoided. The polymerizations with around 70% monomer conversion were conducted in bulk and toluene at relative low temperature of 40 ℃. Number-average molecular weight of resulted polymers ranged from 3000 to 4700 Da by changing the feed ratio between monomer and initiator. The structures of obtained thiolterminated poly(ε-caprolactone) were demonstrated by combining NMR and SEC analyses.     

Theoretical design study on photophysical property of the B–N derivatives for OLED applications

The photophysical properties of a series of multifunctional compounds applied in organic light-emitting diode (OLED) materials have been studied by quantum chemistry. These compounds have been integrated by an electron and hole transporting component as well as an emitting component into the donor–π–acceptor (D–π–A) structures. To reveal the relationship between the structures and properties of these multifunctional electroluminescent materials, the ground- and excited-state geometries were optimized at the B3LYP/6-31G(d), HF/6-31G(d), and CIS/6-31G(d) levels, respectively. The ionization potentials and electron affinities were computed. The mobilities of hole and electron in these compounds were studied computationally based on the Marcus electron transfer theory. The maximum absorption and emission wavelengths of compounds 1–4 were calculated by time-dependent density functional theory method. As a result of these calculations, it was concluded that the electron injections of compounds 2–6 are much easier than Mes₂B[p-4,4′-biphenyl-NPh(1-naphthyl)] (BNPB) due to the introduction of the thiophene group, anthracene group, and N=N as a part of the π-conjugated bridge, compounds 5 and 6 can act as electron transport and hole transport materials, respectively. Compounds 1 and 2 have higher electron mobility and light-emitting efficiency as compared to compounds 3 and 4. Compounds 3 and 4 have quite longer fluorescence lifetimes than compounds 1 and 2 due to the larger Stoke’s shifts.     

微细矩形磁性薄膜体系中一致转动磁化模式

针对经过刻蚀的微细矩形磁性体系，将样品的形状及其磁晶易磁化轴的偏转两个因素引入经典的Stoner-Wohlfarth一致转动磁化模型中，发现磁性样品的微细化将使其特征星形线发生膨胀，而样品形状的缺陷及磁晶易磁化轴的偏转都将导致样品非对称特征星形线的产生.这些结果说明在诸如磁性随机存储器等基于微细磁性薄膜的工作中，薄膜形状及其磁晶易磁轴的角度不容忽略. 关键词： 磁性薄膜 Stoner-Wohlfarth模型 特征星形线 各向异性     

ZnGa2O4∶Cr3+红色荧光粉的光致及电致发光性能

采用柠檬酸络合溶胶-凝胶法合成ZnGa2O4∶Cr3 红色荧光粉,在空气气氛中1000℃煅烧得到ZnGa2O4单相.对粉体进行X射线光电子能谱(XPS)和电子顺磁共振(EPR)测试,结果显示,在空气气氛中煅烧,铬离子以三价形式存在(Cr3 ),未出现高价铬离子(Cr5 ,Cr6 ).Cr3 取代Ga3 占据八面体格位,位于695nm的红光发射带属于Cr3 的2E-4A2跃迁.Cr3 的激发带与基质发射带间有大面积重叠,两者间存在有效的能量传递.利用丝网印刷方法制成电致发光器件,与硫化物电致发光器件相似,ZnGa2O4∶Cr3 电致发光器件的亮度与电压满足L=L0exp(-bV-1/2)关系,且亮度与频率成正比.器件的Q-V曲线为闭合回路,发光效率η约为13lm·W-1.     

Entanglement and non-Markovianity of a spin-S system in a dephasing environment

We study the entanglement （measured by negativity） evolution and the non-Markovianity for the dynamical process of a spin-S system embedded in dephasing environments. The exact analytical solution is presented, which shows that the decoherence function governs the evolutions of coherence, entanglement, and the non-Markovianity of the correspond- ing dynamical processes. For Ohmic and sub-Ohmic reservoirs, the negativity decreases monotonically in time and the corresponding dynamics is Markovian. While for super-Ohmic reservoirs with non-monotonic decoherence function, the negativity appears as the phenomenon of revival and the corresponding dynamics is non-Markovian. The relation between non-Markovianity and the system dimension is studied.     

T型微通道中液滴半阻塞不对称分裂行为研究

液滴不对称分裂是获得不同尺寸微液滴的优选方法,研究液滴不对称分裂行为对于生物医学、能源化工及食品工程等领域具有重要意义.本文研制T型微通道芯片并设计搭建T型微通道液滴半阻塞不对称分裂行为可视化实验平台,研究流量调控对微液滴分裂比的影响规律,并建立理论模型对分裂比进行预测,得到以下结论:液滴不对称挤压分裂过程分为挤压前期、挤压后期和快速夹断阶段,在挤压前期,液滴颈部宽度随时间呈线性变化,在挤压后期,颈部宽度随时间呈指数关系,而在快速夹断阶段,液滴颈部向心收缩的界面附加压力占主导,液滴颈部宽度剧烈收缩,呈断崖式减小;调控分支通道流量可对液滴不对称分裂比进行调控,且调控作用受毛细数影响较大;基于液液流动压降模型的液滴分裂比预测模型能够有效预测液滴分裂比.