微波消解-电感耦合等离子体质谱(ICP-MS)法测定板栗中的矿物元素及稀土元素

为了准确测定板栗中矿物元素和稀土元素的含量水平,采用冷冻干燥方式预处理样品,选用硝酸和过氧化氢体系微波消解样品,结合电感耦合等离子体质谱技术,建立了板栗中钠(Na)、钾(K)、镁(Mg)、锰(Mn)、铁(Fe)、钒(V)、钴(Co)等19种矿物元素及镧(La)、铈(Ce)、镨(Pr)、钕(Nd)、钐(Sm)、铕(Eu)、钆(Gd)、铽(Tb)、镝(Dy)、钬(Ho)、铒(Er)、铥(Tm)、镱(Yb)、镥(Lu)、钇(Y)等15种稀土元素的同时分析测定方法。方法检出限为0.0027~0.78μg/L,相对标准偏差为1.4%~6.3%。通过国家标准物质GBW10019苹果的准确度实验验证,测定结果均在标准证书值范围内。实验结果表明,方法适用于板栗中矿物元素及稀土元素的同时测定。     

An efficient method for solving the mixed direct-inverse problem of the transonic rotational flow in plane casades

The method in [1] has been extended to the case of rotational flow in this paper. A new method for dealing with the shock wave is presented. This method has the advantages of both the shock-fitting and the shock capturing methods. The direct problem and the mixed direct-inverse problem of the rotational flow in a transonic plane cascade at both design and off design conditions are solved, and the results show that the present method has rapid convergence rate and high accuracy even for the flow with moderately strong shocks. The calculations have been carried out on the DPS-8 computer, and for the direct problem, only 50–80 iterations are needed, and 50–80 seconds of CPU time are required.     

基于小波域马尔可夫随机场模型的压缩传感图像重构

目前在压缩传感重构算法中利用图像的可稀疏性表示先验知识,从比奈奎斯特采样少得多的观测值中恢复原始图像。除了稀疏性之外,邻域系数的相关性也可以作为先验知识加速重构算法收敛。为了克服目前算法中没有利用邻域系数相关性的缺点,提出了基于小波域马尔可夫随机场模型的压缩传感图像重构算法,根据显著性度量对变换系数进行分类得到具有马尔可夫性的初始掩模,利用ICM算法完成掩模优化,实现系数更新,并将算法与未考虑邻域相关性的算法进行了比较。实验结果证明了算法的有效性。     

多阶变截面杆的弹性稳定计算

本文研究单阶和多阶截面杆在集中和分布轴向荷载作用下的弹性稳定计算方法,首次给出了其整体稳定和局部稳定的解析解.     

多层流体的Marangoni对流

介绍微重力环境下矩形液池中多层不相混液体的Marangoni对流及其不稳定性.Marangoni对流流动的形成是由于在该系统施加一个与液体交界面相垂直的外加温度梯度.Marangoni对流的线性不稳定性分析是基于无限延长矩形液池内的两层流体系统.应用数值模拟研究了Marangoni对流的流体动力学和热传输特性,将多层流体的Marangoni对流同两层流体中外加温度梯度与流体交界面平行时引起的热毛细对流的主要特征进行了比较.     

扭转变形平面假设的讨论

在对圆轴扭转平面假设的内涵进行分析的基础上, 关联其在应力分析中 的应用, 并讨论了平面假设成立的条件以解释矩形截面翘曲现象, 可作为该部分课堂教学的 参考材料.     

抗震结构的模糊随机反应及模糊可靠性分析

本文研究抗震结构模糊随机反应的计算方法,合理地考虑了地震作用的随机性及地震烈度、场地土分类和破坏界限内可靠性分析方法。     

MH－Ni电池低温性能的研究

从合金组成及电解液组份研究了ＭＨ－Ｎｉ电池的低温性能,确定了适宜的合金组成和电解液组成。     

Emissions of polycyclic aromatic hydrocarbons from coking industries in China

This study set out to assess the characteristics of polycyclic aromatic hydrocarbon（PAH） emission from coking industries,with field samplings conducted at four typical coke plants.For each selected plant,stack flue gas samples were collected during processes that included charging coal into the ovens（CC）,pushing coke（PC） and the combustion of coke-oven gas（CG）.Sixteen individual PAHs on the US EPA priority list were analyzed by gas chromatography/mass spectrometry（GC/MS）.Results showed that the total PAH concentrations in the flue gas ranged from 45.776 to 414.874μg/m³,with the highest emission level for CC（359.545μg/m³）.The concentration of PAH emitted from the CC process in CP1（stamp charging） was lower than that from CP3 and CP4（top charging）.Low-molecular-weight PAHs（i.e.,two- to three-ring PAHs） were predominant contributors to the total PAH contents,and Nap,AcPy,Flu,PhA,and AnT were found to be the most abundant ones.Total BaP_eq concentrations for CC（2.248μg/m³） were higher than those for PC（1.838μg/m³） and CG（1.082μg/m³）,and DbA was an important contributor to carcinogenic risk as BaP in emissions from coking processes.Particulate PAH accounted for more than 20%of the total BaP_ec| concentrations,which were significantly higher than the corresponding contributions to the total PAH mass concentration（5%）.Both particulate and gaseous PAH should be taken into consideration when the potential toxicity risk of PAH pollution during coking processes is assessed.The mean total-PAH emission factors were 346.132 and 93.173μg/kg for CC and PC,respectively.     

Rayleigh-Marangoni-Benard instability in two-layer fluid system

Rayleigh-Marangoni-Bénard instability in a system of two-layer fluids is studied numerically. The convective instabilities in the system of Silicon Oil (10cSt) and Fluorinert (FC70) liquids have been analyzed. The critical parameters at onset of convection are presented in a large range of two-layer depth ratios from 0.2 to 5.0. Numerical results show that the instability of the two-layer system depends strongly on its depth ratio. When the depth ratio increases, the instability mode changes from mechanical coupling to thermal coupling. Between these two typical coupling modes, a time-dependent oscillation is detected. Nevertheless, traveling wave states are found in the case of oscillatory instability. The oscillation mode results from the competition between Rayleigh instability and Marangoni effect. The project supported by the National Natural Science Foundation of China (10372105) and the Knowledge Innovation Program of Chinese Academy of Sciences (KJCX2-SW-L05)