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Search Results: 1 - 10 of 129836 matches for " 杜凤华 "
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NaLa1-xEux(WO4)2的燃烧法制备及发光性能
Combustion Synthesis and Luminescence Properties of NaLa1-xEux(WO4)2 Phosphors
 [PDF]

钱先, 张大, 明霞, 高岩岩, 蒲锡鹏, 张秀兰, 马婧
Material Sciences (MS) , 2012, DOI: 10.12677/ms.2012.21003
Abstract: 采用燃烧法制备了系列NaLa1–xEux(WO4)2红色荧光粉,探索了煅烧温度及Eu3+掺杂量对样品结构与发光性能的影响。分别利用X射线粉末衍射仪(XRD)、紫外/可见/近红外分光光度计(UV-vis)以及荧光分光光度计(PL)对样品进行了表征。结果表明:得到的样品具有四方晶系的白钨矿结构;荧光粉在紫外–近紫外波段均有较强的吸收,在394 nm近紫外光激发下得到发射谱图的主要发射峰为Eu3+的5D0→7F1橙光和5D0→7F2红光特征跃迁发射,红光发射的强度是橙光发射的~6.2倍,有利于得到色纯度较高的荧光粉。
NaLa1–xEux(WO4)2 red phosphors were successfully synthesized by the combustion method. The influences of calcination temperature and Eu3+ doping amount on the structure and luminescence properties of as-synthesized sam-ples were explored. The phase composition and optical properties of as-synthesized samples were studied by X-ray powder diffraction and photoluminescence spectra. UV-vis spectra were used to measure the light absorption spectrum of the phosphors. The results show that the samples have the similar scheelite phase structure belonging to tetragonal system and have strong absorption in the region of UV and near-UV. The luminescence results show that the emission spectra under 394 nm excitation consist of the orange region 5D0?7F1 (594 nm) and the red region 5D0?7F2 (617 nm). The high ratio of the red emission to the orange emission is advantageous to obtain a phosphor with good CIE chroma-ticity coordinates.
Advances in Research on Xanthoceras sorbifolia
文冠果(Xanthoceras sorbifolia)研究进展

高述民,马凯,,
植物学报 , 2002,
Abstract: 综述了文冠果(Xanthoceras sorbifolia Bunge.)的落花落果、雄性不育、遗传变异、快繁及药用等方面的研究进展。认为造成文冠果“千花一果”的生理原因可能在于树体营养不足;导致雄性不育的主要原因可能在于花药难以开裂散粉,其次才是花粉败育;文冠果花瓣等突变体的发现及体细胞胚培养成功,为优选、快繁新品种及研究木本植物的各个器官的形态建成分子机理等提供了条件,但文冠果的资源在逐年减少,有待尽快加以保护和利用;文冠果的药用价值尚有待国内深入系统地研究。
辽宁西部低山丘陵区植被恢复研究:基于演替理论和生态系统退化程度
晓军,,焦志
应用生态学报 , 2004,
Abstract: 在对辽宁西部地区植被演替分析的基础上,选用不同演替阶段的生境指标,应用聚类分析方法,定量确定了辽宁西部低山丘陵区退化生态系统的退化程度.在辽宁西部地区,南刘杖子林场的天然栎林、天然油松林、杨栎林、牛河梁和欺天林场坡地的人工油松林与天然松栎林的平均相异系数分别为0.655、0.665、2.029、3.919,综合反映了其在生态系统演替/退化中的相对位置.研究表明,辽宁西部低山丘陵区现有油松林(阴坡)立地大多已退化到灌木林和先锋乔木林之间的演替阶段,并且接近于先锋乔木林阶段;建议在现有人工林经营改造或营造混交林时,应适当增大灌木树种和先锋乔木树种的比重.
文冠果(Xanthocerassorbifolia)研究进展
高述民,马凯,,
植物学报 , 2002,
Abstract: ?综述了文冠果(XanthocerassorbifoliaBunge.)的落花落果、雄性不育、遗传变异、快繁及药用等方面的研究进展。认为造成文冠果“千花一果”的生理原因可能在于树体营养不足;导致雄性不育的主要原因可能在于花药难以开裂散粉,其次才是花粉败育;文冠果花瓣等突变体的发现及体细胞胚培养成功,为优选、快繁新品种及研究木本植物的各个器官的形态建成分子机理等提供了条件,但文冠果的资源在逐年减少,有待尽快加以保护和利用;文冠果的药用价值尚有待国内深入系统地研究。
用23na和27al固体核磁共振研究na+在γ-al2o3上的吸附状态
,有如,叶朝辉,孔渝
物理化学学报 , 1994,
Abstract:
基于WorldView-2高分辨率卫星影像的信息提取技术
Information Extraction Technology of WorldView-2 High-Resolution Satellite Image
 [PDF]


Geomatics Science and Technology (GST) , 2014, DOI: 10.12677/GST.2014.22004
Abstract:
WorldView-2是世界上首颗能够提供8个波段多光谱数据的高分辨率商业卫星。在对WorldView-2影像8个波段的光谱特征充分分析的基础上,运用WorldView-2影像的地物样本库,并利用面向对象的信息提取技术,分析典型地物的光谱、纹理、几何等特征,提取耕地、林地、园地、水域、道路、居民地及工矿用地等典型地类,验证WorldView-2卫星8波段数据的信息提取效应与精度。这对于WorldView-2影像在测绘、国土、环境等行业,以及国家大型项目(如地理国情监测)的深入应用具有积极的推动意义。
WorldView-2 is the first commercial high-resolution satellite to provide 8 spectral sensors in the visible to near-infrared range. Based on analyzing the 8 Spectral features of WorldView-2 and researching on the sample feature libraries of WorldView-2 image, this experiment tried to extract the data on land, woodland, garden plot, water, road, residential area and industrial land etc., and applied the object-oriented information extraction technology, in order to check the information extraction ability and the precision validation of WorldView-2 data. WorldView-2 image has a positive influence on in-depth application in mapping, land, environment industries, etc. and national project (such as geographical condition monitoring).
Vegetation restoration in western Liaoning hilly region:A study based on succession theory and degradation degree of ecosystem
辽宁西部低山丘陵区植被恢复研究:基于演替理论和生态系统退化程度

DU Xiaojun,JIANG Fengqi,JIAO Zhihua,
晓军
,,焦志

应用生态学报 , 2004,
Abstract: Based on the analysis of vegetation succession in western Liaoning hilly region,and by the method of Cluster Analysis with some habitat indexes of different succession stage,this paper quantitatively measured the degradation degree of degraded ecosystems in this region.The results showed that the average dissimilarities between natural Quercus forest,natural Chinese pine (Pinus tabulaeformis) forest and Populus-Quercus forest in Nanliuzhangzi forestry centre and Chinese pine plantations in Niuheliang region and Qitian forestry centre were 0.655,0.665,2.029 and 3.919,respectively,and as a whole,the dissimilarities represented the places of the forests in the process of ecosystem succession /degradation.It was also showed that most habitats were degraded to the stage between shrubbery and pioneer arbor forest,and closer to the succession stage of pioneer arbor forest.Some suggestions were made for the management of the existing plantation and the construction of mixed forest,e.g.,to increase the proportion of shrubbery and pioneer arbor species,especially that of nitrogen fixation tree species.The plant species list of several main vegetation types in western Liaoning we offered could provide scientific reference for the vegetation restoration and the management of pure Chinese pine plantation in this region.
水分对克氏针茅和冷蒿生殖生长的影响
张昊,李鑫,,林国辉,
草地学报 , 2005, DOI: 10.11733/j.issn.1007-0435.2005.02.005
Abstract: 研究克氏针茅(Stipakrylovii)和冷蒿(Artemisiafrigida)的生殖枝数量、重量以及水分对繁殖分配与种群密度、地上生物量之间的关系。结果表明增加水分有利于克氏针茅的生殖生长,而不利于冷蒿;增加水分时,克氏针茅繁殖分配比例随着密度和生物量的增加而呈增加趋势,但冷蒿则呈降低趋势,但随着生物量的增加二者变化不大;水分、密度和生物量的变化对克氏针茅和冷蒿繁殖分配比例均产生影响,表明两者的繁殖分配是与表型可塑性的变化密切相关,而不受遗传控制。
温度胁迫对二化螟滞育幼虫生理指标的影响
强承魁,予州**,于玲雅,秦越,舞剑
应用生态学报 , 2012,
Abstract: 为从生理生化水平上探讨二化螟滞育幼虫应对温度胁迫的生理机制,分别对系列温度胁迫(sts)和梯度温度胁迫(gts)处理后的幼虫水、脂质、总糖、小分子碳水化合物含量及超氧化物歧化酶(sod)、过氧化物酶(pod)、过氧化氢酶(cat)活性进行了测定.结果表明:随着温度的降低,两种处理二化螟滞育幼虫虫体含水量趋于减少,且0℃以下时gts处理下降幅度较sts处理显著;两种处理脂质含量均逐步下降且二者间无显著差异;两种处理总糖含量分别先减后增和持续下降,均检测出4种小分子碳水化合物,其中sts处理葡萄糖、甘油和果糖含量先增后减,海藻糖含量变化与此相反,而gts处理海藻糖含量先减后增,葡萄糖和甘油含量呈相反变化,果糖含量无变化;14~-14℃范围内sts处理sod和pod活性较gts处理低,cat活性相反.二化螟滞育幼虫生理指标的变化反映了其应对不同温度胁迫的生理响应.
半边莲化学成分的研究
韩景兰,,李志宏,,秦海林
中国中药杂志 , 2009,
Abstract: 目的:研究半边莲LobeliachinensisLour.全草的化学成分。方法:用溶剂提取、萃取、硅胶正相柱色谱及结晶法进行化学成分的分离纯化,通过理化性质和波谱分析鉴定结构。结果:从半边莲全草中分离鉴定了7个化合物,结构分别为:5-羟基-4′-甲氧基黄酮-7-O-芸香糖苷(1),正丁基-O-β-D-吡喃果糖苷(2),5,7-二甲氧基香豆精(3),cirsiumaldehyde(4),香叶木素(5),5-hydroxymethyl-2-furancarboxaldehyde(6)和6-羟基-7-甲氧基香豆精(7)。结论:化合物2~4,6,7为首次从该植物中分离得到。
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