束变换环孔激光谐振腔的环束场传输差分计算

 通过使用新的坐标变量和光场的表达形式，推导了新坐标系下环束场传输的偏微分方程，给出了相应差分方程的截断误差和稳定性条件，使得环束场传输计算速度大幅提高；使用二阶精度的Crank-Nicolso差分方法对束变换环孔激光谐振腔的环束场传输进行了计算，并与W.D.Murphy和M.L.Bernabe所给M-B积分近似方法的计算结果进行了比较，证实了该方法无论计算速度和精度都优于M-B积分近似方法。     

简谐势阱中非理想气体玻色-爱因斯坦凝聚转变温度的数值研究

用数值计算的方法研究了简谐势阱中非理想气体的玻色 爱因斯坦凝聚情况.通过计算能级的分布，用图形的方式给出了考虑相互作用时，简谐势阱中体系转变温度相对无相互作用体系转变温度的变化趋势 对于存在排斥作用的体系，转变温度升高；对于存在吸引作用的体系，转变温度降低. 关键词： 玻色－爱因斯坦凝聚 相互作用 能级 转变温度     

免跟踪透射式太阳聚光器的设计

针对目前太阳聚光器中因为自动跟踪系统故障率高导致使用成本大幅度增加的主要制约因素,在多年来探讨有效提高太阳能密度的基础上,提出了免跟踪线性菲涅尔透射式太阳聚光器设计的新思路,并对其结构形式和工作原理进行了阐述.     

掺杂DCJTB聚乙烯咔唑的发光性质

研究了PVK∶DCJTB体系的发光特性。实验结果表明,PVK∶DCJTB薄膜光激发时,PVK和DCJTB之间存在能量传递,DCJTB的浓度从1%增加到2%,能量传递效率明显增强,但仍然不充分。引入Alq3层后的PVK∶DCJTB/Alq3双层薄膜,PVK的发光被有效地抑制了,Alq3明显促进了PVK向DCJTB的能量传递效率,说明Alq3起到了能量传递的"桥梁"作用。而结构为ITO/PVK∶DCJTB/Alq3/LiF(1nm)/Al的器件的电致发光光谱与光致发光光谱明显不同。电致发光时,Alq3层的发光的相对强度比光致发光时大许多,而且发光强度随着驱动电压的增加而增强,说明随电压的增加,有更多的空穴注入到Alq3层,致使载流子在Alq3层的复合几率随电场的增强而增大。     

Deriving Energy-Gap of Some Nonlinear Hamiltonians by Invariant Eigen-operator Method

By virtue of the invariant eigen-operator method we search for the invariant eigen-operators for some Hamiltonians describing nonlinear processes in particle physics. In this way the energy-gap of the Hamiltonians can be naturally obtained. The characteristic polynomial theory has been fully employed in our derivation.     

Molecular depth profiling of polymers with very low energy ions

The need for a molecular depth profiling technique to study organic layers has become a strong incentive in the SIMS community in the last few years, especially with the recent successes obtained with cluster ion beam depth profiling. In this work, we have investigated a thoroughly different approach by using very low energy (down to 200 eV) monoatomic or diatomic ions to sputter organic matter. Quite surprisingly, we were able to retain specific molecular information on various polymers even at very high fluence.Polymethylmethacrylate (PMMA) and polyethylene terephthalate (PET) films were depth-profiled with 200 eV Cs⁺ and 500 eV O₂⁺ ions. With 200 eV Cs ions, the best profiles were obtained in the negative mode, due to a strong negative ionisation yield enhancement related to Cs retention in the polymer. A relatively high and stable signal from the most characteristic ions was measured all over the layer.With 500 eV O₂⁺, real molecular depth-profiles were also obtained in both the positive and the negative modes. Once again, the main characteristic fragments of PET or PMMA remain detectable with stable yields all over the profile.     

Fast and flexible gpu accelerated binding free energy calculations within the amber molecular dynamics package

Alchemical free energy (AFE) calculations based on molecular dynamics (MD) simulations are key tools in both improving our understanding of a wide variety of biological processes and accelerating the design and optimization of therapeutics for numerous diseases. Computing power and theory have, however, long been insufficient to enable AFE calculations to be routinely applied in early stage drug discovery. One of the major difficulties in performing AFE calculations is the length of time required for calculations to converge to an ensemble average. CPU implementations of MD‐based free energy algorithms can effectively only reach tens of nanoseconds per day for systems on the order of 50,000 atoms, even running on massively parallel supercomputers. Therefore, converged free energy calculations on large numbers of potential lead compounds are often untenable, preventing researchers from gaining crucial insight into molecular recognition, potential druggability and other crucial areas of interest. Graphics Processing Units (GPUs) can help address this. We present here a seamless GPU implementation, within the PMEMD module of the AMBER molecular dynamics package, of thermodynamic integration (TI) capable of reaching speeds of >140 ns/day for a 44,907‐atom system, with accuracy equivalent to the existing CPU implementation in AMBER. The implementation described here is currently part of the AMBER 18 beta code and will be an integral part of the upcoming version 18 release of AMBER. © 2018 Wiley Periodicals, Inc.     

Semi-empirical calculations for the ranges of fast ions in silicon

A semi-empirical method is proposed to calculate the ion ranges in energy region E?=?0.025–10?MeV/nucleon. The dependence of ion ranges on the projectile nuclear charge, mass and velocity is analysed. The calculations presented for ranges of ions with nuclear charges Z?=?2–10 in silicon are compared with SRIM results and experimental data.     

Sulfur-Containing Bent N-Heteroacenes

A series of novel sulfur-containing bent N-heteroacenes were constructed and characterized by NMR and UV/Vis spectroscopy, cyclic voltammetry, and single-crystal X-ray diffraction. By introducing sulfur-containing groups (thio, sulfinyl, and sulfonyl) into bent azaacenes, their electronic delocalization was improved and frontier energy levels were modulated. The target products displayed tunable optical and electronic properties through altering the valence of sulfur and fused length of the azaacenes. For the first time, typical products were utilized as organic field effect transistor materials, affording promising results.