Theoretical study on the lithium bond interaction of furan homologues C_4H_4Y (Y=O, S) with LiCH_3 via DFT and MP2

The optimizations geometries and interaction energy corrected by BSSE of the complexes between C4H4Y (Y=O, S) and CH3Li have been calculated at the B3LYP/6-311 G** and MP2/6-311 G** levels. Three complexes were obtained. Abnormally, the calculations showed that all the C10—Li14 bond lengths increased obviously but the blue-shift of C10—Li14 stretching frequency occurred after formed complexes. The calculated binding energy with basis set super-position error (BSSE) and zero-point vibrational energy corrections of complexes I―III is ?45.757, ?35.700 and ?39.107 kJ·mol?1, respectively. The analyses on the combining interaction with the atom-in-molecules theory (AIM) also showed that a relatively strong lithium bond interaction presented in furan homologues C4H4Y---LiCH3 systems. Natural bond orbital theory (NBO) analysis has been performed, and the results revealed that the com- plex I is formed with n-σ type lithium bond interaction between C4H4O and LiCH3, complex II is formed with π-s type lithium bond interaction between C4H4O and LiCH3, and complex III is formed with π-s and n-s type lithium bond interactions between C4H4S and LiCH3, respectively.     

基于决策树方法的银行客户信用评估

分析了传统银行客户信用评估方法存在的问题,针对ID3算法存在的不足,提出了一种改进的ID3算法.实验结果表明,改进后的ID3算法分类正确率有所提高,所生成的决策树较为健壮、简洁,可以减少计算代价,提高计算效率.     

3S技术在土地资源管理中的应用

"3S"技术作为当前信息管理的高新技术,在土地资源管理中具有广阔的应用前景。本文在介绍RS,GIS,GPS及"3S"集成的基础上,从土地利用调查、土地利用总体规划、土地利用动态监测、土地资源评价和土地整理五个方面简要阐述了"3S"技术在土地管理中的应用,并展望了"3S"技术在土地管理中的应用前景。     

欠驱动双足步行机器人运动控制与动力学仿真

以欠驱动双足步行机器人为对象,提出一种基于落脚位置控制的运动控制算法,并对其行走控制过程进行动力学仿真。首先基于三维线性倒摆模型(3D-LIPM)控制机器人的落脚位置,建立其行走姿态的虚拟约束,利用有限时间收敛反馈控制器对行走过程进行控制,实现了机器人的动态稳定行走。最后结合MATLAB的符号运算、SIMULINK和虚拟现实技术对其控制过程进行运动学和动力学仿真。实验结果表明控制算法是可行的。     

大运高速公路立体绿化模式探讨

论述了大运高速公路立体绿化的原则,探讨了大运高速公路立体绿化模式。     

The concentration quenching characteristics of ~5D_3-~7F_J and ~5D_4-~7F_J (J=0―6) transitions of Tb~(3 ) in YBO_3:Tb~(3 ) phosphor

The photoluminescence quenching behaviors of 5D3-7FJ and 5D4-7FJ (J = 0―6) transitions of Tb3 in YBO3:Tb under 130―290 nm excitation were systematically investigated. The results revealed that the quenching concentrations of both 5D3-7FJ and 5D4-7FJ transitions of Tb3 in YBO3:Tb were mainly de-pendent on excitation wavelength. Particularly,the quenching concentrations of 5D4-7FJ transitions of Tb3 under 130―290 nm excitation were correlated with excitation bands of YBO3:Tb. The quenching concentrations of 5D3-7FJ transitions remained at low concentration (2%) under 186―290 nm excitation and then increased gradually with energy of incoming excitation photon when excited at 130―186 nm. This dependence should be involved in their excitation mechanisms and quenching pathway in particular excitation region.     

日本人的“ラち”、“そと”意识与日语的时态转换

从日本人的“ラち”、“そと”意识角度出发，通过对川端康成、志贺直哉的几部小说进行分析统计，探讨日语在描写过去的事件中，插入“内时态‘る’形”的条件和原因。分析发现当作者为了使作品更生动，或是作者与作品中人物产生“同感”时，或是表达作者的主观思想、评论时，往往发生时态的转换。     

如何提高《数字信号处理》课程的教学质量

依据《数字信号处理》课程在电子信息类专业中的地位,从该课程的课堂教学和实验环节两方面入手,探索了提高教学质量的有效途径和方法。     

基于ASP.NET的毕业设计选题系统构建

介绍了ASP.NET技术,并对基于ASP.NET技术开发的B/S结构毕业设计选题系统的功能进行了详释。