小额支付系统的开发设计

该文参考中国移动的有关协议规范,从工程设计的角度阐述了小额支付系统(通过手机进行较小金额的支付)的业务功能、体系结构和通信流程的实现,提出了具有实时性、扩展性、安全性、开放性的小额支付系统的内部架构和各功能模块的概要设计方案,为手机支付业务提供了系统的解决方案。     

阶段波动差分进化算法及函数优化

差分进化算法被认为是一种简单高效的全局优化算法,但其在解决高维复杂优化问题收敛精度过低,为此提出了阶段波动差分进化算法.新算法利用柯西分布随机数设计用于生成变异率的算子,并对变异率进行上下波动.进化过程中引入分段思想,每个阶段分别根据不同的配置利用算子生成变异率并选择对应的交叉比率改善算法性能.同时为了加快收敛速度,设计了一种新的变异处理策略.通过对一组经典Benchmark函数的测试,实验结果显示了本文算法在解决复杂高维问题时具有优于或相当于其他DE算法的性能.     

基于Annotation的Spring AOP系统设计

简要介绍AOP(Aspect Oriented Programming)技术和Annotation技术,讨论了Spring中的AOP的两种实现.通过同一个案例阐述了在Spring中通过XML配置来实现AOP和使用了Annotation在Spring中实现AOP,比较了两种实现方式的优缺点.对在Spring使用Annotation实现AOP作了总结,从而体现了Annotation在设计系统时其简洁性和良好的扩展性.     

基于Annotation的Spring事务应用设计

本文简要介绍Spring的事务实现技术,讨论了Spring中的事务的两种实现方式。通过同一个案例阐述了在Spring中通过xml配置来实现事务和使用了Annotation实现事务,比较了两种实现方式的优缺点。     

Spectral variations of Ca3Sc2Si3O12:Ce phosphors via substitution and energy transfer

The luminescence intensity of emission peak at around 525 nm decreased in the Ce3+ and Er3+ co-doped Ca3Sc2Si3O12 phosphors. Mg2+ ion, which was likely incorporated into the Sc3+ position of the host crystal, was co-doped to adjust the crystal field and compensate for the excess positive charge due to the doping of Ce3+. The green emission belonged to the 5d→4f transition of Ce3+ moved toward longer wavelength by addition of Mg2+ in Ce3+ and Er3+ co-doped Ca3Sc2Si3O12 phosphor, which could increase the brightness of the phosphor. However, the position of weakening of luminescence intensity at around 525 nm remained basically unchanged by increasing the amount of Mg2+. The results showed that the weakening of luminescence intensity at around 525 nm caused by the absorption of Er3+, which had little influence on the environment of the crystal field.     

白光LED用高效荧光转化材料钪硅酸盐的研究进展

由于目前LED用绿色荧光粉体系分别存在热稳定性差、显色指数低、制备复杂苛刻等问题,因此日本三菱化学开发出了一种新型LED用绿色Ca3Sc2Si3O12∶Ce3+钪硅酸盐荧光粉。在综述Ca3Sc2Si3O12∶Ce3+荧光性能的基础上,总结分析了Ca3Sc2Si3O12∶Ce3+荧光发光材料的晶体结构和发光机制,表明这种荧光粉兼备了硅酸盐和YAG∶Ce荧光粉的石榴石结构,使得晶体场能够与Ce3+配合展现出良好的匹配性,可以很好的与现行蓝光芯片匹配得到高品质的白光,并且类似YAG晶体的石榴石结构有着良好的发光性能和热稳定性;讨论了在电荷补偿作用和这种作用下基质改变后荧光粉的性能变化,以及激活剂改变、能量传递的影响,表明荧光粉光色可调幅度较大,能够根据不同变化产生不同的发光;然后分固相法和液相法总结了该荧光粉的制备方法,证明该荧光粉烧结温度低、合成工艺适应性广泛,并且高温固相法是工业化生产该系列荧光粉的最佳方法;最后展望了Ca3Sc2Si3O12∶Ce3+荧光转换材料的发展趋势和在白光LED中的应用前景,作为一种新型高效的白光LED用绿色荧光粉,需要进一步的研究和探索。     

Synthesis and luminescence properties of Sr3-z（AlxSi1-x）O5-xFx：zCe^3＋phosphors

Sr3-z(Alx,Si1-x)O -5-xFx:zCe3+ phosphors were synthesized by high-temperature solid-state reaction.The structure and luminescence properties of phosphors with various Al/Si ratios and Ce3+ concentrations were characterized using various methods such as X-ray diffraction,photoluminescence excitation and photoluminescence spectra.XRD result displayed that a complete solid solution between Sr3AlO4F and Sr3SiO5 was formed.With the increasing of x value,a broader excitation band and stronger absorption appeared in the blue light region.Moreover,the emission band shifted to a shorter wavelength and the emission intensity reached a maximum at x=0.6.By adjusting the concentration of Ce3+,a widely tunable range of emission wavelength under the excitation of 460 nm was obtained from the green to yellow regions.In addition,the concentration and thermal quenching were also discussed.     

Effect of SiN substituting for AI-O bonds on luminescence properties of Sr3AIO4F：Ce3＋ phosphor

Cerium-doped Sr3（A11-x,Six）O4-xNxF oxynitride phosphors with different x values were synthesized by solid-state reaction. The structure and optical properties of these phosphors were investigated by X-ray diffraction （XRD）, energy dispersive spectroscopy （EDS） and photoluminescence （PL） spectra. The XRD results showed that SiN substitution for Al-O） did not change the structure of Sr3A104F host and there was no impurity for x〈0.6. With the increasing ofx values, the absorption of phosphors at the blue region was enhanced and the emitting band varied from 519 to 529 nm under the 460 nm blue light excitation. The red shift of the emission band was associated with an increase in the crystal-field splitting and the covalence, which arose from the incorporation of N. More- over, the incorporation of N also improved the thermal quenching properties and the external quantum efficiency with a maximum value up to 43.3%, indicating that this phosphor is a promising candidate for white LEDs application.     

地方院校数学专业课双语教学分层递进式模式探析

由于各种条件的限制,地方院校在开展双语教学的模式上和重点大学有一定区别.本文针对地方院校数学专业课课堂教学、布置作业、考核、专业术语与常用结构的掌握等方面对双语教学分层递进式模式进行了有益的探索.     

基于Scopus和Scival的稀土材料研究分析

稀土是镧系元素和钪、钇共17种金属元素的总称,具有独特的性质.稀土材料是我国材料领域重点发展的方向,广泛应用于国民经济和国防工业各领域,同时也是国际范围内的研究重点和前沿方向.为全面分析稀土材料领域研究现状及热点主题,本文基于Scopus数据库和Scival科研管理分析平台,针对2015-2020年稀土材料领域的科技文...