掺杂剂与基质材料能量匹配的红色有机发光二极管

1　Introduction　Organiclight emittingdiodes(OLEDs)haveattract edconsiderableattentionduetoitsgreatpotentialinefficiency ,low voltage ,large area ,lightweight ,andfull colorflat paneldisplays[1,2 ] .Forfull colordis plays ,itisnecessarytohaveefficientred ,green ,andblueemitterswithappropriatechromaticity .Bycom parisonwiththehighperformanceofblueandgreenOLEDs ,theperformanceandpurechromaticityofredOLEDsarestillrelativelypoor .UsuallyredOLEDsareimprovedbydopingreddyesintohostmaterialswit…     

《论语》语句疏解

因《论语》为语录体，其编纂“不为义例”，转换灵活，一些语句的注疏、理解存有歧见。本文辑录“学而时习之，不亦说乎？有朋自远方来，不亦乐乎？人不知而不愠，不亦君子乎”等四个语段，着眼于整体，从话题、语意的一致性和内在逻辑联系等方面加以疏解，以求通惬，追近原意。     

"熵"的科学定义

“熵”是热学中一个极其重要的基本概念，追溯它的起源，从物理定义的“完备性”要求，对“熵”从宏观到微观，从“定性”到“定量”分别进行了定义。     

如何正确理解和分析摩擦力

就高中学生在学习摩擦力概念易出现的三方面误区谈一谈高中物理教学过程中应如何引导学生正确理解摩擦力的方向、大小以及做功引起能的转化.     

能源动力仿真实验教学系统设计与应用

简要介绍了清华大学热能工程系建立的能源动力仿真实验教学系统，以及该系统在学生实践教学环节的作用。以仿真实验系统为媒介的教学实践环节，不仅帮助学生了解了实际工程知识和动手操作能力，而且还极大地促进了学生对专业的了解和热爱，培养了团队协作精神，对学生综合素质的培养和学习理论课知识起到了重要作用。     

结合专业进行毕业实习的改革

对现有的集中、统一实习方式进行改革,改过去的统一组织、统一实习的实习模式,鼓励学生在大四寒假期间,到即将分配的单位或与自己将来工作单位工作内容相近的单位实习,并在实施时建立严格的考核制度,确保实习效果,探索毕业实习方式。     

点源电流场中导电球体的电势分布

推证了点源电流场中导电球体内、外的电势分布规律。     

大国油气需求的地缘争夺及中国的应对

冷战结束以来,列强的角逐已经逐渐从不正常的意识形态竞争回归到传统的地缘政治和资源争夺。全球的油气资源在西方跨国石油巨头苦心经营了上百年后已成定局,作为后来者的中国,面对经济飞速增长所产生的巨大的能源需求,如何在既有的利益格局中谋取一席之地,成为中国目前必须应对的困境。     

镍小团簇的基态结构和能量

采用Gupta势来描述Nin团簇中原子之间的相互作用，用模拟自然界生物进化的遗传算法优化计算了Nin团簇（n=2-23）的基态结构和能量，给出了结构和能量随原子数目的变化规律，并讨论了其相对稳定性。     

A new approach to increase the attainable rice yield in intensive irrigated rice systems of Zhejiang province, China

A new site-specific nutrient management approach was developed to break the apparent attainable yield barrier of 6 t·ha⁻¹ in the double rice cropping system of Zhejiang. On-farm experiments involving 21 rice-growing farmer families and NPK long-term experiments commenced in 1997 in the central part of Zhejiang Province to assess the status of soil fertility and productivity under intensive rice-rice cropping. A new site-specific nutrient management (SSNM) approach has been developed for this studied area. Field-specific fertilizer recommendations are calculated considering indigenous nutrient supply, reasonable grain yield targets and corresponding nutrient demand, nutrient balance and nutrient use efficiency, as well as socio-economic factors. The agronomic performance of SSNM was tested against the farmer's fertilizer practice (FFP) in four 1998–1999 cropping seasons. Across seasons and years, SSNM consistently increased plant nutrient uptake, grain yield and profit by about 10%–15% compared to the FFP. Yield levels of 7.5 t·ha⁻¹ or more seem achievable and sustainable through introduction of SSNM and improved extension services in Zhejiang Province. Project supported by the International Fertilizer Industry Association(IFA), the Potash and Phosphate Institute, Canada (PPIC), and International Potash Institute(IPI).