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X射线荧光粉是一种能够将X射线、γ射线、α粒子和中子等高能电离辐射转变成紫外-可见光的发光材料.作为辐射探测材料,X射线荧光粉被广泛的应用于高能物理、医学成像、安全监测、探矿和油井勘探等方面.本文重点分析了近几年来以卤化物、铝酸盐、硅酸盐、磷酸盐以及硅酸盐X射线荧光粉的研究进展,同时对当前和未来一段时间X射线荧光粉的研究趋势进行了分析. 相似文献
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以钛酸四丁酯和硝酸钙为原料,用改进的固相反应法成功合成了CaTiO3：Pr红色荧光粉.为了提高这种荧光粉的发光性能,加入铝离子作为电荷补偿剂,硼酸作为助熔剂,以及加入锌离子和镁离子替代一部分钙离子,并对其发光性能的影响进行了研究.采用X射线衍射、荧光分光光度计和扫描电镜研究了CaTiO3：Pr的物相组成,发光性质和颗粒形貌.结果表明一定量的硼酸、铝离子、镁离子、锌离子能够有效的提高CaTiO3：Pr红色荧光粉发光强度.余辉曲线和发光亮度表明当硼酸与硝酸钙的物质的量之比为0.3,铝离子与硝酸钙的物质的量之比为0.001时Ca0.8Zn0.2TiO3：Pr,Ca0.9Mg0.1TiO3：Pr样品具有最佳的发光性能. 相似文献
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《南阳师范学院学报》2018,(4):6-9
用硝酸钆、钨酸钠、聚乙二醇为基本原料,采用水热法合成了NaGd(WO_4)_2荧光粉,然后通过掺杂Yb(3+)、Er(3+)、Er(3+)、Tm(3+)、Tm(3+)稀土离子获得上转换发光性能.使用X射线衍射和高分辨扫描电镜对样品结构和形貌进行了表征,通过实验研究了稀土离子掺杂比和反应温度对样品发光性能的影响,获得了在980 nm近红外激光激发下,可以发出暖白光的稀土上转换纳米发光材料. 相似文献
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员玉娟 《中学物理教学参考》1995,(5)
提起X射线,大家都知道它也叫伦琴射线,是一种比紫外线波长更短的电磁波,具有很强的穿透能力,并能使荧光物质发光、照相底片感光、气体电离等。高速电子流射到任何固体上都会产生这种射线,如今它已在晶体结构研究、金属探伤、医学影像学诊断等方面取得了广泛的应用。 这种奇妙的、用途广泛的X射线是怎样发现的, 相似文献
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X射线实时成像检测系统具有实时、动态和连续地从各个角度对试件进行检测的优点,在各个领域焊接检验方面已有广泛的应用,本文通过对钛合金环焊缝上双壁透照的试验,验证了壁厚δ≤30mm的钛合金环焊缝在采取一定的屏蔽措施后,可以采用X射线双壁透照实时成像试验,壁厚δ>30mm的钛合金环焊缝不宜采用X射线双壁透照实时成像试验. 相似文献
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《实验技术与管理》2020,(2):54-58
围绕稀土掺杂Y_2W_3O_(12)(YWO)荧光粉的制备及性能表征,设计了一个综合性教学实验。采用水热法制备YWO:RE~(3+)(RE=Eu,Sm,Dy和Tb)荧光粉,利用X-射线衍射仪、扫描电镜、荧光光谱仪对样品的结构、形貌和发光性能进行表征。实验结果表明:YWO:Eu~(3+)、YWO:Sm~(3+)、YWO:Dy~(3+)和YWO:Tb~(3+)荧光粉均具有较好的发光性能,在紫外光激发下,分别发射明亮的红、橙、黄和绿光。该综合性实验现象明显,重现性好,简单易行,能激发学生探索科学问题的兴趣和主动性,强化学生的创新意识和综合素质。 相似文献
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伦琴,德国科学家,首届诺贝尔物理学奖的获得者.他第一个发现了X射线,并制造出了用于医学的X光透视机.
和历史上许多伟大的发明一样,X射线的发现也是一个偶然.1895年11月8日,物理学家伦琴在实验室观察雷钠管的发光现象.他在一间黑暗的房间里给密封在纸套里的雷钠管接通高压电源,让雷钠管放电,以便检查黑色纸套是否漏光.无意中,他发现了一个奇异的现象:附近小工作台上有一块涂了氰亚铂酸钡的纸板发出了一片明亮的荧光.当他切断电源,荧光也随之消失. 相似文献
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Sol-gel法制备Mg掺杂ZnO纳米薄膜晶体结构和发光特性的研究 总被引：3，自引：0，他引：3
采用溶胶-凝胶(Sol-gel)旋涂法在石英衬底上制备Mg掺杂ZnO纳米薄膜,室温下利用X射线衍射(XRD)、光致发光谱(PL)等手段分析所得ZnMgO合金薄膜的晶体结构和发光特性.结果表明:在0.1 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
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Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献