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谷物种子中蛋白质含量测定的核反应分析法 总被引:1,自引:0,他引:1
分析了在高蛋白质谷物育种中对筛选方法的要求, 对谷物中蛋白质测定的方法进行了综述评价, 重点介绍了用于谷物蛋白质测定的核反应分析法的原理及特点. The requirements of the screening method for high protein content in grain breeding are analysed. Methods for the determination of protein content in grain seed are reviewed.The principle and the advantages of the nuclear reaction method for the measurement of protein content in grain seed are discussed in detail. 相似文献
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Boundedness and convergence of perturbed corrections for helium-like ions in ground states 下载免费PDF全文
Applying the improved Rayleigh SchrSdinger perturbation theory based on an integral equation to helium-like ions in ground states and treating electron correlations as perturbations, we obtain the second-order corrections to wavefunctions consisting of a few terms and the third-order corrections to energicity. It is demonstrated that the corrected wavefunctions are bounded and quadratically integrable, and the corresponding perturbation series is convergent. The results clear off the previous distrust for the convergence in the quantum perturbation theory and show a reciprocal development on the quantum perturbation problem of the ground state helium-like systems. 相似文献
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研究和实践表明,反思问题是有效提高我们数学思维品质和能力的途径之一.因此,在教学中,我们应充分抓住教学的契机,如在考试刚结束--"兴奋甫定"的时候,在学生被一种好的解法所吸引--"拍案叫绝"的时候,在"避开云雾终见光"--"眼前一亮"的时候,在捶胸顿足、连呼上当--"懊恼不已"的时候……引导他们进行反思,让他们从现象到本质,从内容到形式,从特殊到一般,在"想通悟透"的基础上,逐步掌握规律性的结论,最终形成模式化的思维,养成良好的思维品质,这才是我们引导学生反思的最终目的.…… 相似文献
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如何降低荧光粉层的温度是白光激光二极管亟待解决的问题。六方晶体氮化硼(hexagonal boron nitride, hBN)是一种高导热材料。目前的研究集中于将hBN随机分布在荧光粉层,但对导热的增强十分有限。本文提出一种基于气泡模板的三维互连hBN导热网络构建方法。通过数值模拟探究了hBN体积分数等因素对模型导热性能的影响。结果表明导热系数随hBN体积分数和气泡体积分数增加而增加;几乎不随气泡粒径变化。最后制备了互连hBN网络的荧光粉层,通过光热测试验证了其优异的性能。 相似文献
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准确定量铀氧化物样品中238U的含量对于裂变产额测量等工作具有重要意义,其定量方法的研究对于涉及238U的绝对测量的诸多实验都具有参考价值。利用四川大学2.5 MeV质子静电加速器产生的准单能中子对八氧化三铀样品进行中子活化,用高纯锗探测器测量活化产物的β衰变子体239Np的277.6 keV特征γ射线,利用已知的活化截面,算出样品中238U的质量占比为79.1%,不确定度为6.2%。利用电感耦合等离子体质谱法对样品中238U的含量进行了测量,其质量占比为59.2%。此外,基于EA3000元素分析仪、卡尔费休电位滴定仪和TGA-DSC2同步热分析质谱联用仪,测知样品中不含N元素,含水量在2.2%以下。并利用PIXE方法排除了样品中含有Al元素以上杂质,利用EPBS方法测知样品中U/O原子数比为1:3.6,误差约2%,推知样品中238U质量占比为80%,验证了活化法测得的238U含量。最终测得样品中238U的质量占比为79.1%,不确定度6.2%。对照按U3O8分子式折算的84.5%,考虑到水分含量等,此结果合理。The accurate quantification of 238U in uranium oxides is of great importance for measurements of fission yield. The study for the method of 238U quantification has significance to lots of experiments involving absolute measurement of 238U. The reaction (n, γ) in the triuranium octoxide samples was induced by T(p,n)3He quasi-monoenergetic neutrons provided by the 2.5 MeV proton electrostatic accelerator in Sichuan University. The 277.6 keV characteristic γ ray of 239Np that comes from β-decay of the activation product 239U was detected by a HPGe detector. With the known (n, γ) cross section, the mass percentage of 238U in samples was determined to be 79.1%, with the uncertainty of 6.2%. ICP-MS was also used in the quantification of 238U in samples, its result was 59.2%. Meanwhile, the samples were analyzed by other several methods and the results showed that less than 2.2% H2O, no nitrogen, and no other impurity elements above Al were contained in the samples. EPBS was used to measure the atomic ratio of U and O and it was found that the mass percentage of 238U in samples was about 80%, verifying the result 79.1% of INAA. 相似文献
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