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张艺 《内江师范学院学报》2014,(12):27-29
用溶剂热法、150℃反应12h成功合成了分散性良好的LaP04：Ce^3＋/Tb^3＋荧光晶体.XRD数据表明,合成了六方晶系的LaP04：Ce^3＋/Tb^3＋晶体（PDF 84-0600）.pH为9.0时,合成晶体的离子最佳摩尔比为nLa^3＋∶nCe^3＋∶nTb^3＋=6∶3∶1.根据荧光光谱可知,LaP04：Ce^3＋/Tb^3＋在270nm处有最强激发峰,在545nm处有最强发射峰,对应于Tb^3＋的5 D4→7F5跃迁. 相似文献
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合成了一系列Eu^3 (Tb^3 )和phen共掺杂的杂化材料，并对其发光性能进行了考察。在所有样品中除了掺杂浓度为1％的样品外，其余材料均为透明块状且无裂纹。所有材料在紫外灯照射下，发出明亮的红光（Eu^3 掺杂）和绿光（Tb^3＋掺杂）。 相似文献
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测量了1．62at％-Er^3＋ Y0.5Gd0．5，VO4晶体的吸收光谱和荧光发射谱，光谱显示该晶体在382、525、1536nm有很强的偏振光吸收峰，且偏振光（E∥C）吸收远强于σ偏振光（E⊥C）吸收；通过计算可得，吸收截面分别为2．95013×10^-20cm^2、2．57757×10^20cm^2和1．15504×10^-20cm^2；其荧光发射（^4I15／2→^4I11／2跃迁）峰值波长在1524nm，半高宽度为72nm；415/2^I→^4I11/2跃迁的荧光寿命为3．1ms,光谱特性表明Er3^＋：Y0．5，Gd0．5，VO4晶体是潜在的高效率激光晶体材料． 相似文献
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采用水热法,结合后续的热处理,制备了Eu^3＋掺杂的ZnF2-ZnO纳米结构材料,利用X-射线衍射仪（XRD）、扫描电子显微镜（SEM）和荧光光谱仪对样品结构、形貌及发光性能进行表征．结果表明,以NaF为原料得到的样品为正方体状,长为220-400nm;以NH4F为原料得到的样品呈棒状,长约为1．2μm,直径为110nm左右．紫外光激发下,棒状样品发光性能强于立方体状的样品,表现为掺杂Eu^3＋的特征发射．光催化脱色实验表明,两种形貌样品的光催化活性差别不大,150min对甲基橙的脱色率达70％左右． 相似文献
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将功率为30W．波长为1064nm的YAG激光束（束斑直径0．045mm）照射在硅样品表面打出小孔，在孔内的侧壁上有很特殊的网孔状结构，其中的网孔壁厚为纳米尺度，解释孔侧壁网孔状结构的机理．孔侧壁上的网孔状结构有很强的受激荧光发光效应，发光峰中心约在700nm处．当样品在加工和检查过程中保持脱氧状态时，其样品几乎没有发光，证实了氧在PL发光增强上起着重要作用．我们用量子受限及其纳晶与氧化硅界面态复合的综合模型来解释其光致发光的增强机理 相似文献
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采用荧光光度法测定了鸡肉和鱼肉肌肉中洛美沙星药物的残留量．样品用酸性乙腈提取,正己烷脱脂,水相在B—R（pH3．0）缓冲溶液中,激发波长λex=275nm,荧光波长λem=450nm下用荧光光度法测定其中的洛美沙星含量,洛美沙星线性范围是10~120μg／mL,相关系数r=0．9958,检出限为0．005μg／mL．样品回收率为76．0％-94．5％,日内变异系数为2．14％~6．50％,日间变异系数为3．02％～9．78％． 相似文献
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以聚乙烯基吡咯烷酮（PVP）为表面包覆剂，在室温大气条件下的水溶液中制备了ZnS：Mn^2＋和ZnS：Mn^2＋、Pb^2＋纳来晶．XRD分析表明纳米尺寸的平均直径为2-4nm，TEM分析表明纳米尺寸均一，用荧光光谱检测到其激发波长（λexc≈410nm）和发射波长（λem≈510～560nm）都在可见光范围以内，显示出一种新颖的光致发光性质，并对这一性质作出了适当的解释．这些结果表明共掺杂的纳米晶代表了一种新型的发光材料． 相似文献
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采用X射线衍射、红外光谱和荧光光谱研究了Ca1-xCdxTiO3：Pr^3＋的物相组成及发光性质。X射线衍射和红外光谱研究表明掺入适量的Cd^2＋物相组成为CaTiO2。激发光谱是峰值位于330nm附近的宽带谱，发射光谱是峰值在625nm半宽度为20nm的带谱。对应Pr^3＋的ID2-3H4跃迁发射。发光强度随基质组分Cd／Ca摩尔比和合成温度而变化。Cd^2＋的最佳含量在15％～20％. 相似文献
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在77K测定了标题配合的激发光谱和荧光光谱，在配合物的^7F→^D0激发光谱里，580．14nm和580．68nm处呈现两个锐锋，说明在该配合物中存在两种Eu^3 格位，选择激发配合物的^5D0能级，得到两组完全不同的^5D→^7FJ(J=1,2）荧光光谱，表明配合物中Eu^3＋离子具有不同的化学环境，两种格位的可能点群是C1，C2或Cs，可能具有与Y2（P－CH3C6H4COO）6（C12H8N2）2类似的晶体结构。 相似文献
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对钝顶螺旋藻藻胆体在解离过程中77K荧光发射光谱与光能传递途径进行了研究．在77K荧光发射光谱中，完整藻胆体只有一个峰，位于682nm，这是藻胆体核心一类囊体膜连接多肽的荧光峰；随着藻胆体逐渐解离，首先在649nm出现一个小峰，之后，在661nm又出现一个荧光发射肩，前者是C-藻蓝蛋白的荧光，后者是别藻蓝蛋白的荧光；随着藻胆体解离程度的加重，C-藻蓝蛋白的荧光逐渐加强并成为主峰，别藻蓝蛋白的荧光也逐渐加强，但随后又逐渐减弱，直至消失；682nm主峰逐渐减弱并消失，但在679nm却出现另一个荧光峰，这是别藻蓝蛋白-B的荧光，当别藻蓝蛋白的荧光消失后，679nm荧光峰减弱为荧光发射肩，但仍然有很强的荧光。这表明：C-藻蓝蛋白不但与别藻蓝蛋白相连接，而且还与别藻蓝蛋白-B相连，在钝顶螺旋藻藻胆体中，光能是沿着两条途径传递给光系统Ⅱ的。 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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《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
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献