有效数字在环境监测中的应用

对实验中常用的玻璃量具如单标线吸管、容量瓶、比色管、刻度吸管等进行分析,确定了直读式数据的读数规则及有效位数。如10mL单标线吸管有效数字位数为5位,而10mL刻度吸管随移取溶液体积不同其有效数字位数可能为2,3或4位。分析了环境监测中间接式数据的来源,如标准溶液的浓度、标准曲线的截距、斜率、样品最终浓度等,这些数据应当遵守一定的修约及运算规则,由此确定了间接式数据应当保留合理的有效位数。研究结果可以为环境监测人员开展实验及数据处理提供依据。     

Chemical composition and nutritional properties of Terminalia catappa L. oil and kernels from Benin

This work focuses on the physico-chemical characterization of kernels and oil of Terminalia catappa L. from Benin. The detailed physico-chemical properties are given including the nutritional composition and fatty acid profile, but also the phenolic content, phytochemical screening and antioxidant capacity which were determined for the first time. The kernel (100 g) contained 5.5 g of moisture, a high level of lipids (64.7–140.4 of Recommended Daily Intake (RDI)), proteins (36.0% RDI), sugars (6.0% RDI), and tannins (0.6%). The defatted kernels (100 g) contained high levels of manganese (184.8–236.1% RDI), magnesium (173.6–235.2% RDI), iron (89.7–201.9% RDI), zinc (87.9–120.9% RDI) and calcium (41.5% RDI), and contributed for 98.6% of RDI proteins. The kernel oil showed a high level of unsaturated fatty acids including oleic (27.1%) and linoleic acids (26.6%) and saturated fatty acids such as palmitic acid (40.0%) as well as several phytosterols and triterpenes. These kernels and their unsaturated oil are of interesting nutritional value but could also be used as a biofuel or lubricant. The presence of phenolic and terpenic derivatives may also explain at least in part their use in traditional medicine.     

色度学实验研究

本文通过实验验证了颜色相加、相减的规律及任意复色光与汞灯的色坐标、色调、色饱和度的测量及三原色滤色片的透过滤测定等各项实验内容。并对复色光的研究分别用精确算法与粗略算法进行了分析研究。     

Poisson convergence in the restricted k‐partitioning problem

The randomized k‐number partitioning problem is the task to distribute N i.i.d. random variables into k groups in such a way that the sums of the variables in each group are as similar as possible. The restricted k‐partitioning problem refers to the case where the number of elements in each group is fixed to N/k. In the case k = 2 it has been shown that the properly rescaled differences of the two sums in the close to optimal partitions converge to a Poisson point process, as if they were independent random variables. We generalize this result to the case k > 2 in the restricted problem and show that the vector of differences between the k sums converges to a k ‐ 1‐dimensional Poisson point process. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2007     

Stationary values of the ratio of quadratic forms subject to linear constraints

Sommario SiaA una matrice reale simmetrica di ordinen, B una matrice reale simmetrica di ordinen per cuix ^T B x>0 eC una matricen×p di rangor conrp. Si vogliono deteminare i vettorix per cui, JIMELè stazionaria eC ^T x= è il vettore nullo. È dato un algoritmo per generare un autosistema simmetrico i cui autovalori sono i valori stazionarì e per determinare i vettorix. Sono altresì presentate parecchie applicazioni dell'algoritmo.

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Dedicated to Professor L. Collatz on his sixtieth birthday

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This author was in part supported by the Atomic Energy Commission.     

<Emphasis Type="Italic">L</Emphasis><Subscript>1</Subscript> linear interpolator for missing values in time series

We propose a minimum mean absolute error linear interpolator (MMAELI), based on theL ₁ approach. A linear functional of the observed time series due to non-normal innovations is derived. The solution equation for the coefficients of this linear functional is established in terms of the innovation series. It is found that information implied in the innovation series is useful for the interpolation of missing values. The MMAELIs of the AR(1) model with innovations following mixed normal andt distributions are studied in detail. The MMAELI also approximates the minimum mean squared error linear interpolator (MMSELI) well in mean squared error but outperforms the MMSELI in mean absolute error. An application to a real series is presented. Extensions to the general ARMA model and other time series models are discussed. This research was supported by a CityU Research Grant and Natural Science Foundation of China.     

Linear prediction of record values for the two parameter exponential distribution

This paper deals with the problem of predicting thesth record value based on the firstm record values (s>m) when the observations are from the exponential distribution. Various estimates for thesth record value are obtained and their mean square errors are compared.     

Back-bending in182,184,186osmium

The high spin yrast states uptoJ=22⁺ in^182,184,186Os are studied in a microscopic variational approach with number-conserved projected states. The energy spectra, quadrupole, moments andB (E2) values are calculated by employing the Hamiltonian with quadrupole plus pairing interactions. The results of the calculations are in fair agreement with the available experimental data.