工频市电直接驱动的白光交流发光二极管

韩国某半导体公司发明的交流发光二极管（ACLED），利用220V（或110V）的交流电直接驱动。台湾地区某研究院研发的ACLED立体导热可插拨封装，使ACLED光源更换像白炽灯泡一样便利。尽管目前ACLED功率仅为5W，发光效率还不及DCLED高，但因其不需要变压器和恒流源驱动电路，具有应用简便、效率高、成本低等优势，其发展前景诱人。     

白光LED的天敌-有机EL（1）

白光LED媒体宣称是电灯问世之后的最大发明。LED也公认是未来薄型电视的主要背光源模块接棒人，同时也是绿建筑新照明的今日之星。然而，却有匹黑马如潜水艇般宁静地在水面下匍匐前进，即将浮出台面与LED对峙。那就是顶顶有名的有机EL。乃是照明业超级大黑马，有机电子学的时代悄悄来临!     

白光LED用Ce∶YAG微晶玻璃的研究进展

Ce∶YAG微晶玻璃是一种可替代荧光粉用于白光LED的新型高性能荧光材料。综述了YAG微晶玻璃的制备方法、性能影响因素、发光机理,指出了Ce∶YAG微晶玻璃应用于白光LED的优势,并展望了白光LED用YAG微晶玻璃的发展趋势。     

多种粒子成核的声空化核效应研究

0引言自2002年以来,Taleyarkhan等[1-3]采用不同的成核方法进行了声致核聚变(acoustic cavitation fusion,ACF)研究。有关ACF的实验报道,得到了国际科学界的高度重视,也引发了一场至今尚无定论的有关ACF效应的争辩[4-5]。本文回顾本课题组近年来利用快中子、裂变中子、以及α粒子作为成核粒子进行声空化核效应(Nuclear Effect of Acoustic Cavitation,NEAC)的实验研究,阐述不同载能粒子对声核效应的影响。     

基于嵌入式IOC的CSNS真空控制系统样机研制

在EPICS软件框架下搭建了一套中国散裂中子源(CSNS)真空控制系统样机.使用MOXA嵌入式工控机运行嵌入式Linux系统,并建立相应的EPICS系统,实现EPICS与真空设备(真空计和离子泵电源控制器)的接口.真空连锁保护系统则用横河PLC实现,并在该PLC的嵌入式Linux控制器模块上建立EPICS系统,使PLC中的数据直接纳入EPICS系统中.通过测试表明,该样机实时性较高且稳定可靠.     

混合压片型241AmO2-Be中子源物理特性研究

Am-Be中子源是应用广泛的同位素中子源,国际上为其建立了ISO 8529-1推荐标准。为检验该标准的普适性和各种应用的需求,本文以德国PTB实验室ISO源和北京大学核物理与核技术国家重点实验室的国产同类源为例,对源中子从产生到出射的物理过程进行蒙特卡罗模拟和理论计算。综合评述了源的制作和结构差异等因素对源中子能谱、平均能量、1.5 MeV以下中子的份额、源强、源发射4.438 MeVγ射线与中子的强度比和出射中子的各向异性等源自身物理特性的细致影响。     

CSNS束流损失监测系统前端模拟电路设计

中国散裂中子源(CSNS)束流损失监测系统利用气体电离室来探测束流损失,电离室输出信号需在前端模拟电路中进行信号处理。本工作自主设计开发了束流损失测量系统前端模拟电路,采用跨导放大的方式实现了低重复频率、低占空比、弱电离室信号的电流 电压（I-V）变换测量。同时,电路还实现了对较大束流损失的快速响应,保障加速器设备的安全运行。联机测试结果表明,该电路满足系统要求。     

先进裂变核能的关键核数据测量和CSNS白光中子源

在设计加速器驱动的次临界系统（ADS）、核废料嬗变装置及钍基熔盐堆时亟需一些关键核数据,当前核数据库受实验条件或中子能区的限制,存在核数据精度不高甚至少部分核素数据缺失的情况。本文综述了国内外相关的核数据研究和相应的白光中子源情况。基于中国散裂中子源(CSNS)的反角通道白光中子源实验终端的中子束流具有非常宽的能谱（0.01 eV~200 MeV）和很好的时间特性。模拟得到距靶80 m处的实验终端的中子注量率为9.3×10⁶cm^-2•s^-1,1 eV ~ 1 MeV能量间隔内的中子数占总中子数的53%;同时,加速器运行在双束团模式或单束团模式,时间分辨率均在0.3%～0.9%之间,适合开展核数据测量。     

Synthesis and photoluminescence properties of a red emitting phosphor NaSr2（NbO3）5：RE3＋（RE=Sm,Pr） for white LEDs

Rare earth Sm3＋, Pr3＋doped NaSr2（NbO3）5 red phosphors were successfully synthesized. X-ray diffraction analysis indi-cated that all the samples were single phased. The luminescence property was investigated in detail by diffuse-reflectance spectra and photoluminescence spectra measurement. Both NaSr2（NbO3）5：Sm3＋and NaSr2（NbO3）5：Pr3＋phosphors showed strong absorption in near ultraviolet region, which was suitable for application in LEDs. When excited by UV light, they both emitted bright red emission with CIE chromaticity coordinates （0.603, 0.397） and （0.669, 0.330）, respectively. The optimal doping concentration of Sm3＋doped NaSr2（NbO3）5 was measured to be 0.04 and that for Pr3＋doped NaSr2（NbO3）5 was 0.01. The integral emission intensity was also measured and compared with the commercial red phosphor Y2O3：Eu3＋. The results indicated that NaSr2（NbO3）5：RE3＋（RE=Sm, Pr） have potential to serve as a red phosphor for UV pumped white LEDs.     

Enhanced photoluminescence of CaTiO3：Eu3＋ red phosphors prepared by H3BO3 assisted solid state synthesis

CaTiO₃:Eu³⁺ red phosphors were prepared using H₃BO₃ assisted solid state synthesis. The structure and morphology of the obtained sample were observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). And the luminescence property was measured using photoluminescence excitation (PLE) and photoluminescence (PL) spectra, respectively. In the excitation spectra, main excitation peaks of the prepared samples were centered at 397 and 465 nm, revealing that these phosphors could be excited by commercial GaN- and InGaN-typed light emitting diodes (LEDs). Dominant emission peaks of the phosphors were located at 616 nm, owing to the transition of ⁵D₀→⁷F₂ of Eu³⁺. In the optimum condition, CaTiO₃:3%Eu³⁺ phosphor was obtained at a sintering temperature of 1200 °C in air with a content of 20 mol.% H₃BO₃ addition. When excited by 397 nm irradiation, the PL intensity of as-prepared red phosphor was 2.2 times higher than that of samples obtained by traditional solid state synthesis, while the PL intensity was 3 times higher than that excited by 465 nm irradiation. The added H₃BO₃ improved the crystallinity, and increased the color purity, implying the potential to be a promising red phosphor in white light emitting diodes (WLEDs).