Luminescence characteristics of LiCaBO_3:Tb~(3+) phosphor for white LEDs

A novel green phosphor,LiCaBO3:Tb3+,was synthesized by solid state reaction method,its luminescence characteristics were investigated,and the formation of phosphors were confirmed by X-ray powder diffraction(XRD).Its excitation band extended from 220 to 400 nm,which was coupled well with the emission of UV LED(350-410 nm).It exhibited a strong green emission located at 544 nm with chromatic coordination(0.25,0.58).The emission intensities of LiCaBO3:Tb3+ phosphor were influenced by varying Tb3+ concentratio...     

水工隧洞施工贯通测量的实践

本文结合实践,就水工隧洞贯通的洞外控制测量和洞内监理测量的方法、要点作了介绍,并对一些难点及细节问题     

白光发光二极管用LiBaBO3:Eu3+材料的发光特性

采用固相法制备了LiBaBO3:Eu3+材料,并研究它的发光特性。LiBaBO3:Eu3+材料的主发射峰位于594、613、651nm和686nm,分别对应Eu3+的5D0→7F1、5D0→7F2、5D0→7F3和5D0→7F4跃迁;监测613nm发射峰,对应的激发光谱主峰为260、329、368、400nm和470nm。研究了Eu3+含量对LiBaBO3:Eu3+材料发射强度的影响,结果表明:随Eu3+含量的增大,发射强度先增大后减小,Eu3+摩尔分数为3%时,发射强度最大,依据Dexter理论知浓度猝灭机理为偶极-偶极相互作用。掺入电荷补偿剂Li+、Na+和K+均提高了LiBaBO3:Eu3+材料的发射强度。     

Luminescent properties of Eu³⁺-doped BaZrO₃ phosphor for UV white light emitting diode

A novel orange phosphor Eu3+ doped barium zirconate(BaZrO3) was synthesized by conventional solid state reaction method and its crystal structure and luminescent properties were investigated in this paper.The X-ray diffraction patterns(XRD) showed that simple BaZrO3 phase was obtained.Monitoring at 596 nm,the excitation spectrum consisted of a broad band and a series of narrow bands and the stronger excitation peaks located at 275 and 393 nm,respectively.The emission spectrum excited by 393 nm UV light was composed of four narrow bands.The strongest emission was located at 596 nm.The appropriate concentration of Eu3+ was 0.025(molar fraction) for the highest emission intensity at 596 nm.The H3BO3 and ammonium were added as flux and the results showed that 2 wt.% NH4F ions was the optimal flux for BaZrO3:Eu3+.     

蒸发器循环泵的改造

我厂蒸发工段采用三效顺流蒸发工艺,将电解液蒸发成30％浓度的液碱。由于蒸发器上的强制循环泵机封经常泄漏,造成消耗高、产量低、污染作业环境,生产十分被动。泄漏严重时,生产被迫停车。原蒸发器采用SPZ—450型轴流泵,泵体与蒸发器效体连接方式用联轴器刚性连接,泵轴与效体密封为机械密封。自     

三层C／S的机理及在宾馆管理中的应用

本文主要分析了三层C／S结构的机理、特点和表现形式,并和传统的集中式、文件服务器式结构作了比较详细的比较,最后以C Builder3和MSSQLServer6.5为例说明了三层C／S结构的建立过程及在宾馆管理中的应用。     

加强创新体系建设 推进采矿增长方式转变

企业是创新的主体,创新是长久的稳定和风险的克星。近几年来,梅山矿业公司采矿场走出了一条依靠创新求发展之路。采矿场是矿业公司的主体生产单位,主要承担采矿生产和二期采矿扩建,采用竖井与斜坡道联合开拓、竖井提升矿石、阶段有轨运输、无底柱分段崩落法采矿,一期采矿于１９７５年投产,１９８７年原矿产量突破１５０万ｔ。为保证矿山持续发展,在组织生产的同时,矿山从１９８６年开始,先期进行了一期采矿延伸,历时６年,完成了３６万ｍ３的开拓工程量,实现了阶段运输水平由一期采矿的－１９８ｍ向二期采矿的－３３０ｍ的转换,１９９４年着手二期采矿工程建设,１９９９年９月２号主井峻工投产,２０００年３月主斜坡道顺利贯通。至此,梅山将在今后逐年提高采矿综合生产能力,逐步形成４００万ｔ／ａ的采矿生产规模。回顾矿山采矿的发展史,是一部创新的历史,特别是近几年来,以观念创新为前提,以科技创新为根本,以机制创新为动力,以管理创新为手段,以文化创新为灵魂,以形成规模效益为目标,不断加强创新体系建设,形成了采矿低成本经营态势,稳步推进了采矿增长方式的转变。１９９８年原矿产量突破２５０万ｔ,实现了梅山一期采矿设计规模达产,创世界单竖井提升先进水平。１９９９...     

光子晶体光纤在飞秒激光技术中的应用

简要介绍了光子晶体光纤的基本结构、导光机制和主要特性,系统综述了光子晶体光纤在锁模光纤激光器的色散补偿和偏振控制、飞秒激光脉冲的压缩、飞秒激光脉冲的光谱变换,以及飞秒激光器的频率转换等激光技术中的应用研究进展.     

Ca2B5O9Cl:Eu2+蓝色荧光粉的发光特性

采用高温固相法合成了Ca2B5O9Cl:Eu2 蓝色荧光粉,并对其发光性质进行了研究.该荧光粉在近紫外370 nm激发下的发射光谱为峰值位于453 nm的宽带发射,对应了Eu2 的4f65d→4f78S7/2特征跃迁发射.监测453nm的发射峰,得到其激发光谱为250～450nm的宽带,与产生350～410nm辐射的紫外发光二极管(ultraviolet light-emitting diode,UV-LED)管芯匹配很好.当CaCl2用量为理论用量的1.1倍,H3BO3用量为理论用量的1.3倍,Eu2 掺杂浓度为6%时,蓝光发射最强.Ca2B5O9Cl:Eu2 是适合UV-LED管芯激发的白光发光二极管用高亮度蓝色荧光粉.     

醋酸改性钢渣与沥青粘附性图像评价方法

钢渣具有过高的膨胀性限制其使用,醋酸改性可解决钢渣膨胀率过高的问题,但醋酸酸性环境会降低钢渣表面的碱性,势必会改变改性钢渣与沥青的粘附性.为了准确评价改性钢渣与沥青的粘附性能,选用像素法评价改性钢渣与沥青的粘附性,这种方法避免了传统目测法只能定性评价钢渣骨料粘附性带来的问题.结果表明:目测法在10％、30％剥落面积界限...