【摘 要】
：
Novel trivalent europium (Eu3+)-activated La7Ta3W4O30∶xEu3+ (x =0.5 mol％-40 mol％) red-emitting phosphors were synthesized by means of a high-temperature solid-st
【机 构】
：
College of Chemistry & Pharmacy,Northwest A&F University,Yangling 712100,China;College of Chemistry
论文部分内容阅读
Novel trivalent europium (Eu3+)-activated La7Ta3W4O30∶xEu3+ (x =0.5 mol％-40 mol％) red-emitting phosphors were synthesized by means of a high-temperature solid-state reaction.The structure,morphology,photoluminescence,thermal-stability properties,lifetime,and color-rendering of the pre-pared phosphors were investigated in detail.The La7Ta3W4O30∶Eu3+ phosphors show five emission peaks under near-ultraviolet (n-UV) at 397 nm,and these peaks are ascribed to the transitions of 5D0-7Fj (j =0,1,2,3 and 4) by Eu3+ ions.The optimal doping concentration of Eu3+ is 20 mol％,and the critical distance of the energy transfer between the Eu3+ ions was calculated to be 1.768 nm.The quenching temperature(T0.5) of La7Ta3W4O30:20 mol％Eu3+ is about 440 K.The quantum yield (QY) was measured to be 85.85％.The fabricated white-light-emitting diodes (w-LEDs) possess high color-rendering index (Ra) of 90,and high correlated color temperature (CCT) of 5810 K,respectively.The Commission Internationale de L'Eclairage (CIE) coordinates are (0.311,0.322).Therefore,the prepared phosphor has a promising appli-cation for w-LEDs.
其他文献
本试验采用贱金属促进王水溶解贵金属合金,采用磷酸三丁酯(TBP)逆流离心萃取实现金与铂的高效彻底分离,采用亚硫酸钠还原有机相,实现金的回收提纯。试验结果表明,金铂回收率高达98%,金纯度可达99.95%。
Langbeinite type compounds are a large kind of oxometallate with good flexibility structure.Herein,we synthesized a new langbeinite type compound K2Dy1.5Ta0.5(PO4)3,in which the Dy3+and Ta<
水文地质是煤矿床勘查的重要内容,它影响煤矿床后期的开采和利用。本文概述了煤矿床水文地质类型,详细地介绍了常用的水文地质勘查方法,并分析了各类煤矿床适合采用的水文地质勘查方法,为煤矿床水文地质勘查提供借鉴。
本次研究在开阳县采集耕地土壤样6836件、异常查证土壤样120件、土壤剖面3条和成土母岩样3件。耕地土壤重金属元素含量变化范围较大,Cu、Zn、As、Cd、Cr、Hg、Ni、Pb和Tl含量平均值比中位值和背景值高,存在明显的As-Hg、Pb和Cd高值异常区。根据实地采样情况分析,耕地土壤重金属含量异常由农业生产、交通运输和污水灌溉等人为因素引起的可能性较小。As-Hg异常区、Pb异常区和Cd异常区重金属异常主要由地层重金属元素含量高引起,As-Hg异常区也可能受矿业活动影响。
Particle size reduction of Y3Al5O12:Ce(YAG:Ce) phosphor is highly needed for micro-LED display applications.In this work,size control of YAG:Ce phosphor particles is achieved via carbon coating and further heat treatment.A
本文介绍了立磨机的工作原理,在实验室采用KLM-3型立磨机对石英砂进行磨矿试验研究,确定适用于该机的选型试验参数.其间对赤峰某铜炉渣进行了选型试验研究,根据试验结果,推荐
有机污泥无害化处理与处置已成为环境研究热点,也是清洁生产的发展方向之一。采用掺入固化剂的化学固结法可以使有机污泥具有一定的自硬能力,改善其强度或承载力,从而形成具有同等一般工程性质的土工材料,实现再生资源化,促进清洁生产。通过采用配方(每千克污泥掺加水泥、粉煤灰和煤渣分别为0.12、0.02、0.10 kg)对有机污泥进行固化处理,经6 d养护后,固化效果较好,满足填埋处理要求。本文对经6 d养护的纯污泥块及污泥固化块进行了X射线衍射(XRD)试验和扫描电子显微镜(SEM)试验,分析其微观结构。分析认为,
In this comparative study,Tb and Tm substituted Sr-hexaferrites (HFs) with the chemical compositions of SrTbxFe12-xO19 and SrTmxFe12-xO19 (x =0.00,0.02 and 0.04
本文基于生物监测技术原理和作用,结合水环境工程监测内容,分析了水环境工程中常见的几种生物监测技术,并阐述了生物监测技术目前存在的问题及处理措施,以期为我国生态环境保护做出贡献。
填埋作为一种技术成熟、成本较低的处理方式,被广泛应用在生活垃圾处理领域。但是,填埋后的生活垃圾在腐化及其他作用下会生成具有高污染性的渗滤液,其对生态环境的危害十分严重。现阶段并没有效果很好的渗滤液处理工艺,人们只能结合实际情况,采取针对性措施来减少渗滤液的危害。因此,加强对渗滤液处理技术的研究刻不容缓。基于此,本文全面研究了生活垃圾填埋场渗滤液的处理及利用方法。