Raman Analysis of Polymerization of APST Molecule

In this work we investigated the solidification of aminopropylsilanetriol dissolved in water (∼25%) under different conditions by Raman spectroscopy. The solidification was carried out at three different temperatures 8 °C, 23 °C and 60 °C. The influence of electromagnetic radiation on the polymerization process was also studied. Samples were held to solidify in dark and at UV (254 nm and 356nm) spectral range. In order to investigate the influence of the substrate on the resulting polymer structure, teflon, PVC, glass, brass and silica were used. Best ordered polymerized structure was achieved for samples deposited on plastics and solidified in dark, at room temperature.     

Design of a reentrant double staggered ladder circuit for V-band coupled-cavity traveling-wave tube

The reentrant double staggered ladder slow-wave structure is employed in a high-power V-band coupled-cavity traveling-wave tube. This structure has a wide bandwidth, a moderate interaction impedance, and excellent thermal dissipation properties, besides the easy fabrication. A well-matched waveguide coupler is proposed for the structure. Combining the design of attenuators, a full-scale three-dimensional circuit model for the V-band coupled-cavity traveling-wave tube is constructed. The electromagnetic characteristics and the beam--wave interaction of this structure are investigated. The beam current is set to be 100 mA, and the cathode voltage is tuned from 16.8 kV to 15.8 kV. The calculation results show that this tube can produce a saturated average output power over 100 W with an instantaneous bandwidth greater than 1.25 GHz in the frequency ranging from 58 GHz to 62 GHz. The corresponding gain and electronic efficiency can reach over 32 dB and 6.5%, respectively.     

飞秒激光脉宽对三态阶跃型分子波包运动的影响研究

用含时波包法研究了三态阶跃型K2分子在强飞秒泵浦-探测激光场中脉宽对波包动力学过程的影响.研究表明激光场强较弱或者脉宽较短都可能不出现Autler-Townes分裂.波包的振荡周期随脉宽增长而增大,而振荡幅度随脉宽增长而减小. 脉宽影响Rabi振荡,而Rabi振荡的变化又导致了基态和激发态布居数周期性变化．首次量化了脉宽对激发态布居数的影响,表明变化频率随着泵浦场强的增强而增大．研究表明调节激光脉宽可实现对态布居数的选择性分布,可以为实验上实现分子的光控制提供重要参考．     

Dynamics of a three-level V-type atom driven by a cavity photon and microwave field

We discuss the dynamics of a three-level V-type atom driven simultaneously by a cavity photon and microwave field by examining the atomic population evolution. Owing to the coupling effect of the cavity photon, periodical oscillation of the population between the two upper states and the ground state takes place, which is the well-known vacuum Rabi oscillation. Meanwhile, the population exchange between the upmost level and the middle level can occur due to the driving action of the external microwave field. The general dynamic behavior is the superposition of a fast and a slow periodical oscillation under the cooperative and competitive effect of the cavity photon and the microwave field. Numerical results demonstrate that the time evolution of the population is strongly dependent on the atom–cavity coupling coefficient g and Rabi frequency ?_e that reflects the intensity of the external microwave field. By modulating the two parameters g and ?_e, a large number of population transfer behaviors can be achieved.     

Kerr介质中光场与V型三能级原子依赖强度耦合相互作用系统的原子偶极压缩

利用全量子理论,研究了Kerr介质中单模光场与V型三能级原子依赖强度耦合的相互作用系统中原子偶极压缩效应,采用数值计算的方法讨论了Kerr介质常数χ和失谐量Ω对原子偶极压缩的影响.结果表明:Kerr效应对原子偶极压缩效应起着不同程度的减弱作用,适当大小的失谐量Ω有利于原子偶极压缩.     

Photochemical synthesis of a ladder diborole: a new boron-containing conjugate material

Climbing the ladder: Reductive cyclization of alkynyl haloboranes lead to the bis-benzocycloborabutylidene rather than the expected ladder diborole, despite the former being much less thermodynamically favored. Photochemical conversion to the ladder diborole was, however, quite facile upon irradiation at 254?nm.     

“右旋糖酐-磁性层状复合氢氧化物-氟尿嘧啶”给药系统的超分子组装表征与急毒性水平

用"前体共沉淀-离子交换插层-原位复合-溶剂转换"技术合成"右旋糖酐-磁性层状复合氢氧化物-氟尿嘧啶"(DET-MLDH-FU,DMF)运载系统,通过XRD,IR,TEM,TG表征及体外释放实验研究了DMF的物相特征与缓释性能,通过对小鼠灌胃和腹腔注射给药考察了DMF与载体MLDH的急毒性水平.结果表明,DMF等超分子的XRD与R-六方LDH衍射特征相符,是Fe3.6Fe0.9(O,OH,Cl)9型LDH及微量Fe3O4的复合晶相,DMF具有DET,MLDH与FU分级组装形成的核壳式构造.体外pH 7.35 PBS溶出介质中,DMF的药物释放遵守零级模型C-1.162×10-5=4.566×10-7t,速率常数4.566×10-7 mol-1?L?m-1.DMF,MLDH-FU及MLDH可经正常代谢排出体外,口服毒性小;腹腔注射DMF的LD50为2542.8 mg?kg-1,MLDH的LD50为1951.0 mg?kg-1,均属低毒性物质.DET的复合组装对Fe(II,III)LDH构架有抗氧化保护作用,对不同MLDH-FU粒子进行选择、分离与包封,提高MLDH-FU的缓释效果、强化MLDH的控释性能,降低给药系统DMF的急毒性水平.     

Λ型和V型三能级原子与耦合腔相互作用系统中场的量子特性

研究了能级结构分别为Λ型三能级和V型三能级结构的两个原子和通过光纤耦合的由双模腔构成的复合系统中光场的压缩效应、二阶相干度和亚泊松分布等量子特性。利用数值计算方法讨论了光纤模与腔场间的耦合强度对量子特性的影响。研究结果表明:双模光场不呈现压缩效应,但呈现出反关联和亚泊松分布的量子特性;随着光纤模与腔场间耦合强度的增强,亚泊松分布减弱。     

Modeling nonlinear optics of nanosystems with sum-over-states model

Three-stage strategies (ladder rule, few state model (FSM), and parallelization) were proposed to improve the computational efficiency of the sum-over-states (SOS) model in nonlinear optics (NLO) modeling. Ladder rule decomposes NLO coefficients of the nth state into the (n-1)th term and the contribution from the (n-1)th to the nth state without loss of rigor in theory. FSM singles out the states with substantial contribution to NLO. Those strategies are universal to all (including revised and simplified) SOS models. The computing cost reduces roughly to C/(n(i-1)) (C is a constant and i is the rank (order) of the NLO coefficients).     

Demonstration of the approximation of eliminating atomic excited populations in an atom-cavity system

Using the master equation approach to a V-type three-level atom inside a high-finesse single-mode cavity in the strong coupling condition,we demonstrate the approximation of eliminating populations of atomic excited states,which is widely used in the field of the atom-cavity systems [Hechenblaikner G,Gangl M,Horak P and Ritsch H 1998 Phys.Rev.A 58 3030];Liu L W,Tan T and Xu Y 2008 J.Mod.Opt.56 968;Cho J,Angelakis D G and Bose S 2008 Phys.Rev.A 78 062338.This is reflected in the deviation of the population δ,of which the value is 10～(-3)～10～(-2).We further find the deviation of the dipole force and demonstrate that the deviation of atomic population will not notably affect the dipole force of the atom in the strong coupling condition.A relevant experimental case is also presented.