基于激光诱导荧光的常见机油快速识别方法

基于激光诱导荧光光谱原理,提出一种常见机油的快速识别方法。利用激光器发射波长为355 nm的紫外激光,诱导九种常见机油样品发射荧光,共采集450组荧光光谱数据,其中360组数据用于分类训练,90组数据用于识别。分析发现不同机油的荧光光谱特征有明显差异,利用主成分分析结合聚类分析法实现了对90组待识别光谱数据的快速识别,识别率可达97.8%。实验证明,激光诱导荧光光谱结合多元分析可以实现不同机油的快速识别与检测。     

数码相机与计算机在物理教学中的应用

 科学技术的不断更新,造就了教育的现代化,“课本、粉笔加黑板”的传统教学模式必将被丰富多彩的现代化教学手段所代替。数码摄影不但丰富了课堂教学手段,而且提高了多媒体教学软件的质量。本文针对数码相机与计算机的特点,就其在物理教学领域的应用进行了初步探讨。一、数码相机的特点数码相机携带灵活方便、操作直观简便,不需特别的学习和训练,可通过亮度补偿或调整CCD芯片灵敏度等方法,在不同光线强度下拍出理想的照片。目前,一般数码相机的分辨率都在百万像素以上,500万像素的数码相机已经很常见,有的分辨率可达1600万像素,再加上数码相机本身采用的处理技术,其拍摄效果已不亚于传统相机。     

化学气相沉积(CVD)工艺对ZnS力学性能影响的研究

介绍了化学气相沉积法(CVD)制备ZnS过程中,CVD工艺对材料相关力学性能的影响和控制方法.通过X射线衍射分析、扫描电镜和金相显微镜等手段研究了不同工艺下制备的ZnS样品材料的内部结构和缺陷,提出了ZnS生长过程中晶粒尺寸和材料缺陷的控制方法.研究结果表明,设计合理的喷嘴结构,营造稳定的CVD生长环境,提高CVD ZnS毛坯一致性,抑制材料缺陷形成,有助于提升ZnS材料力学相关性能.     

Astrophysical ~(22)Mg(p,γ)~(23)Al reaction rates from asymptotic normalization coefficient of ~(23)Ne→~(22)Ne+n

The radionuclide ~(22)Na generates the emission of a characteristic 1.275 MeV γ-ray. This is a potential astronomical observable, whose occurrence is suspected in classical novae. The ~(22)Mg(p, γ)~(23)Al reaction is relevant to the nucleosynthesis of ~(22)Na in Ne-rich novae. In this study, employing the adiabatic distorted wave approximation and continuum discretized coupled channel methods, the squared neutron asymptotic normalization coefficients(ANCs)231 for the virtual decay of Ne → ~(22)Ne + n were extracted, and determined as(0.483 ± 0.060) fm~(-1) and(9.7 ± 2.3) fm~(-1) for the ground state and the first excited state from the experimental angular distributions of ~(22)Ne(d, p)~(23)Ne populating the ground state and the first excited state of ~(23)Ne, respectively. Then, the squared proton ANC of ~(23)Al_(g.s.) was obtained as C_(d5/2)~(2)(~(23)Al)(2.65 ± 0.33) × 10~3 fm~(-1) according to the charge symmetry of the strong interaction. The astrophysical S-factors and reaction rates for the direct capture contribution in ~(22)Mg(p, γ)~(23)Al were also presented. Furthermore, the proton width of the first excited state of ~(23)Al was derived to be(57 ± 14) eV from the neutron ANC of its mirror state in ~(23)Ne and used to compute the contribution from the first resonance of ~(23)Al. This result demonstrates that the direct capture dominates the ~(22)Mg(p, γ)~(23)Al reaction at most temperatures of astrophysical relevance for 0.33 T_9 0.64.     

基于动态BP网络误差修正的广义预测控制

针对建模误差对非线性系统预测控制鲁棒性的影响 ,提出了一种基于动态 BP网络的广义预测控制算法 .该算法运用动态 BP网络对模型预测误差进行在线补偿 ,以提高预测精度 .仿真结果证明了本文提出的广义预测控制算法对于非线性系统是有效的