Bi^(3+)、Eu^(3+)共掺杂La_(4)GeO_(8)荧光粉的制备及可调发光

为了开发出高效稳定的单一基质白光发射荧光材料,本工作通过高温固相法成功合成了一系列La_(4)GeO_(8)∶Bi^(3+),Eu^(3+)荧光粉样品,并通过X射线衍射、室温光谱、变温光谱等手段研究了实验样品的结构与发光性能。研究发现,Bi^(3+)离子在该结构中占据两种不同的格位(Bi^(3+)(Ⅰ)和Bi^(3+)(Ⅱ)),且在紫外光激发下呈现两个峰值分别在475 nm和620 nm的宽带发射。对于Bi^(3+)、Eu^(3+)共掺样品,由于Bi^(3+)(Ⅰ)与Eu^(3+)之间的竞争吸收、Bi^(3+)(Ⅰ)至Bi^(3+)(Ⅱ)以及Bi^(3+)(Ⅱ)至Eu^(3+)的能量传递作用,可实现蓝色至红色、橙红色至红色的可调发光。特别地,样品La_(4)GeO_(8)∶0.07Bi^(3+),0.06Eu^(3+)在313 nm光激发下可获得CIE值为(0.335,0.319)的优异白色发光。此外,该白光发射材料具有较佳的发光热稳定性,当温度升高至380 K时,发光积分强度仍然为室温的59%,表明其在白光二极管上具有潜在的应用价值。

基于易班平台的思政微课的推广与应用

易班平台异常流行与火爆,主因源于易班平台的思政微课充分彰显了新科技、新媒体、创新教学的魅力,契合了教学相长的教育规律。易班平台思政微课是高校思政教育形式的创新,对培养大学生的思想素质、政治觉悟有着不可或缺的重要作用。基于易班平台的思政微课对涵养天之骄子素质能力的巨大功能。本文将就易班平台的思政微课的推广与应用等问题展开探讨,希望为广大从事思政工作的同行,提供一点理论上的参考。

Exciting rogue waves, breathers, and solitons in coherent atomic media

We propose a scheme that excites rogue waves via electromagnetically induced transparency(EIT),which can also excite breathers and solitons.The system is a resonantΛ-type atomic ensemble.Under EIT conditions,the envelope equation of the probe field can be reduced to several different models,such as the saturable nonlinear Schr?dinger equation(SNLSE),and SNLSE with the trapping potential provided by a far-detuned laser field or a magnetic field.In this scheme,rogue waves can be generated by different initial pulses,such as the Gaussian wave with(or without)the uniform background.The scheme can be used to obtain rogue waves,breathers and solitons.We show the existence regions of rogue waves,breathers,and solitons as the function of the amplitude and width of the initial pulse.The novelty of our paper is that,we not only show rogue waves in the integrable system numerically,but also present the method to generate and control rogue waves in the non-integrable system.