In the course of the development of high school , the nea organized some committees on the function , curriculum and school system of high school . these committees made fruitful efforts and put forward a lot of constructive suggestions 在美国中学发展的过程中，全国教育协会曾就中学的功能、课程以及学制等问题成立一些专门委员会，并进行了卓有成效的工作，对中学的发展提出了许多富有建设性的意见，从而极大地推动了美国中学的发展。
The combination of negative electron affinity ( nea ) photocathode and micro channel plate ( mcp ) brings the iii image intensifier . because of its high performance , the iii image intensifier has been developed rapidly and used widely in the short several decades after it had been found 负电子亲和势( nea )光电阴极和微通道板( mcp )的结合产生了三代像增强器，由于这类像增强器具有优良性能，在发现后的短短数十年中获得了迅猛发展和广泛应用。
In view of the problems existing in the research and producing of the iii image tube in our country , a study of the iii image intensifier have been carried on , the work introduced in this dissertation is as following : ( 1 ) the way to evaluate the properties of nea photocathodes has been proposed . that is using the spectral response and xps measurement results to determine the property parameters of nea photocathodes 本文针对国内在三代管研制方面存在的问题，围绕“三代像增强器研究”作了以下工作： ( 1 )研究nea光电阴极的性能评估，提出通过光谱响应和变角xps测试确定阴极特性参量，从而有效地解决nea光电阴极的性能表征问题。
( 3 ) the spectral matching factor of nea phothocathodes for reflecting spectrum of objects under night sky radiation has been studied . the spectral matching factors of typical phothocathodes , such as gaas nea photocathode , s _ ( 251 ) and s _ ( 252 ) photocathode , are calculated and compared . the factors give the explanation of high detection performance of the low - light - level night vision equipments ( 3 )研究了nea光电阴极和夜天光照射下景物反射辐射的光谱匹配系数，计算了gaasnea光电阴极的光谱匹配系数，并将之与s _ ( 251 ) 、 s _ ( 252 )光电阴极的计算结果作了比较，揭示了三代微光夜视仪具有优良探测性能的原因。
( 2 ) on - line spectral response measurement is used to make a research on the activation process . the on - line measurement results have been analyzed and the influence excised by cs , o activation on the photoemission property of gaas wafers has been revealed . the properties of domestic and foreign nea phocathodes are compared , and the reasons causing the gap between domestic and foreign phocathodes are discussed ( 2 )利用光谱响应在线测试技术研究nea光电阴极的激活工艺，通过对在线测试的光谱响应曲线进行分析、比较和计算，剖析了激活工艺给阴极光电发射性能带来的影响，并从性能评估的角度，比较了国内外nea光电阴极的性能，分析了它们之间存在差距的原因。
In its 150 years " history , the association has brought far - reaching influence on american education . american high school and teaching profession being two cases , this dissertion analyzes the function of nea in the development of american education so as to provide our educational reform and development with useful experience 本文试以美国中学和美国教师专业化的发展为个案，对全国教育协会在美国教育发展进程中的作用进行具体的分析与探讨，从而揭示出该协会在美国教育发展进程中的历史功能，以及对我国教育改革和发展的借鉴意义。
Thus the number of targets in the same approximate cluster is not so large , which reduce the computational cost for the plot - track association . to compute the position estimation amsjpda takes into consideration all the measurements in the validation gate . added all the measurements multiplied by their power , which is taken as the coefficient in computation , the nea r optimal estimation can be achieved 基于近似聚，利用完全联合概率关联算法中的关联计算方法，考虑目标相关门内所有的回波，根据相关程度不同赋给每个回波不同的权值，通过加权计算得到近似最优的目标状态估计。
Many international organizations including the international atomic energy agency iaea , the united nations scientific committee on the effects of atomic radiation unscear , and the organization for economic co - operation and development nuclear energy agency oecd nea have published reports on the event , death toll , radiation dose and impact on health and environment 多个国际组织例如国际原子能机构iaea联合国原子辐射效应科学委员会unscear及经济合作与发展组织核能机构oecd nea都对事故过程，伤亡情况，辐射剂量和健康及环境影响作出报告。本文参考多个报告的内容，就切尔诺贝尔核事故作一概要介绍。
