分光光度法同时测定硅石中的铁和铝

在邻二氮菲(Phen)、铬天青S(CAS)和十四烷基二甲基苄基氯化铵(TDMBA)的共同存在下,于pH 5～6的酸性介质中,铁、铝分别生成Fe-Phen和Al-CAS-TDMBA络合物,用同一份试液,在波长510 nm测定铁,在625 nm测定铝,两种络合物互不干扰。用该法可同时测定硅石中的铁和铝。     

离子色谱法测定烟草种植用有机肥中4种阴离子

氮是影响烟草生长快慢、叶片大小以及产量的关键因素,氮还是烟碱的组成成分,对烟叶香气组成、吸味及刺激性均有重要作用;磷可以促进细胞分裂,提高烟株抗旱性能,施用磷肥过多,烟株暴长、叶片厚、组织粗糙,烤出的烟叶弹性较差、油分少、不利于回软;用量不足,烟株根系生长发育不好、成熟期推迟;硫不是叶绿素的成分,但影响叶绿素的合成;     

条件密度置信区间的覆盖精度

本文用经验似然方法讨论了条件密度的置信区间的构造. 通过对覆盖概率的Edgeworth展开得到了经验似然置信区间的覆盖精度, 同时证明了条件密度的经验似然置信区间的Bartlett可修正性     

The determination of the thickness and the optical dispersion property of gold film using spectroscopy of a surface plasmon in the frequency domain

We propose to use wavelength modulation approach,i.e.,the spectroscopy of a surface plasmon in the frequency domain,to characterize the optical dispersion property of gold film.Using this method,we determine the dispersion relationship of gold film in a wavelength range from 537.12 nm to 905.52 nm,and our results accord well with the reported results by other authors.This method is particularly suited for studying the optical dispersion properties of thin metal films,because a series of dielectric constants over a wide spectral range can be determined simultaneously via only a single scan of the incident angle,thereby avoiding the repeated measurements required when using the angular modulation approach.     

Continuous imaging space in three-dimensional integral imaging

We report an integral imaging method with continuous imaging space. This method simultaneously reconstructs real and virtual images in the virtual mode, with a minimum gap that separates the entire imaging space into real and virtual space. Experimental results show that the gap is reduced to 45% of that in a conventional integral imaging system with the same parameters.     

Equivalent theorems on simultaneous approximation by combinations of Bernstein operatores

In this paper we give equivalent theorems on simultaneous approximation for the combinations of Bernstein operators by r-th Ditzian-Totik modulus of smoothness ωτψλ (f, t)(0 ≤λ≤ 1). We also investigate the relation between the derivatives of the combinations of Bernstein operators and the smoothness of derivatives of functions.     

10—14 μm同时响应的双色量子阱红外探测器

实现截止波长为11.8和14.5 μm双色同时响应的量子阱红外探测器,可以同时工作在8—12 μm大气窗口和甚长波波段.在77 K下测量到很强的光电流谱.器件结构采取了较为简洁的设计,通过适当增大量子阱结构中势阱的宽度和选择合适的掺杂浓度,在同一偏压下实现了对两个波长的同时响应.两个光响应峰分别为基态到第五激发态和基态到第一激发态的跃迁吸收. 关键词： 量子阱红外探测器 双色 同时响应     

相对论问答

郭汉英教授生前曾为我刊撰写过多篇有关相对论的文章,引起了读者广泛的兴趣,他曾建议我们就读者来信中所提的问题开展有关的讨论。这次,我们趁选登赵峥教授所著《相对论百问》的机会,请赵教授帮助回答读者来信中所提的一些问题,来开展有关相对论的讨论,作为对郭汉英教授多年来支持我刊的感谢与怀念,以慰他的在天之灵。     

NA样本下基于递推型核估计的概率密度函数的经验似然推断(英文)

在NA样本下, 本文研究了基于递推型估计的概率密度函数的置信区间的构造, 证明了分块经验似然比统计量的极限分布为χ~2分布, 并利用此结果构造了概率密度函数的经验似然置信区间.     

基于混合Ⅱ型删失数据的Weibull模型精确推断和可接受抽样计划(英文)

本文考虑基于混合Ⅱ型删失数据的Weibull模型精确推断和可接受抽样计划.得到威布尔分布未知参数最大似然估计的精确分布以及基于精确分布的置信区间.由于精确分布函数较为复杂,给出未知参数的另外几种置信区间,基于近似方法的置信区间.为了评价本文的方法,给出一些数值模拟的结果.且讨论了可靠性中的可接受抽样计划问题.利用参数最大似然估计的精确分布,给出一个可接受抽样计划的执行程序和数值模拟结果.