碘量法测定水中溶解氧

针对碘量法中反应试剂硫酸锰溶解缓慢、实验周期较长并伴有大量沉淀的现象,进行了氯化锰和硫酸锰对比实验,结果证明,采用氯化锰替代硫酸锰作反应试剂较好.对影响碘量法测定结果的因素进行了研究,控制适量的氯化锰和硫酸加入量.可提高碘量法的准确度.     

On Attractors for Multivalued Semigroups Defined by Generalized Semiflows

In this paper we extend results from Semigroup Theory on existence and characterization of attractors in order to include multivalued semigroups T(t) defined by generalized semiflows content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figa_HTML.gif" alt="MediaObjects/11228_2006_37_Figa_HTML.gif" align="middle">. In particular we show that, if content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figa_HTML.gif" alt="MediaObjects/11228_2006_37_Figa_HTML.gif" align="middle"> is continuous, possesses a Lyapunov function, and content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figa_HTML.gif" alt="MediaObjects/11228_2006_37_Figa_HTML.gif" align="middle"> has a global attractor content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figb_HTML.gif" alt="MediaObjects/11228_2006_37_Figb_HTML.gif" align="middle"> which is maximal compact invariant, then content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figb_HTML.gif" alt="MediaObjects/11228_2006_37_Figb_HTML.gif" align="middle"> =  W ^u (Z(content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figa_HTML.gif" alt="MediaObjects/11228_2006_37_Figa_HTML.gif" align="middle">)), where Z(content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figa_HTML.gif" alt="MediaObjects/11228_2006_37_Figa_HTML.gif" align="middle">) is the stationary solutions set and W ^u (Z(content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figa_HTML.gif" alt="MediaObjects/11228_2006_37_Figa_HTML.gif" align="middle">)) is the unstable set of Z(content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figa_HTML.gif" alt="MediaObjects/11228_2006_37_Figa_HTML.gif" align="middle">). We introduce the content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figc_HTML.gif" alt="MediaObjects/11228_2006_37_Figc_HTML.gif" align="middle">-attractor concept which does not enjoy any uniformity on time of attraction and we prove, under suitable conditions, that the global content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figc_HTML.gif" alt="MediaObjects/11228_2006_37_Figc_HTML.gif" align="middle">-attractor content/a8015133t651m4h8/11228_2006_37_Article_IEq10.gif" alt="$\widehat{N}$" align="middle" border="0"> is the set of asymptotic states described by Z(content/a8015133t651m4h8/MediaObjects/11228_2006_37_Figa_HTML.gif" alt="MediaObjects/11228_2006_37_Figa_HTML.gif" align="middle">). Jacson Simsen is supported by CAPES-Brazil.     

Approximately solving multiobjective linear programmes in objective space and an application in radiotherapy treatment planning

In this paper, we propose a modification of Benson’s algorithm for solving multiobjective linear programmes in objective space in order to approximate the true nondominated set. We first summarize Benson’s original algorithm and propose some small changes to improve computational performance. We then introduce our approximation version of the algorithm, which computes an inner and an outer approximation of the nondominated set. We prove that the inner approximation provides a set of content/6j13428826525320/186_2008_220_Article_IEq1.gif" alt="$${\varepsilon}$$" align="middle" border="0">-nondominated points. This work is motivated by an application, the beam intensity optimization problem of radiotherapy treatment planning. This problem can be formulated as a multiobjective linear programme with three objectives. The constraint matrix of the problem relies on the calculation of dose deposited in tissue. Since this calculation is always imprecise solving the MOLP exactly is not necessary in practice. With our algorithm we solve the problem approximately within a specified accuracy in objective space. We present results on four clinical cancer cases that clearly illustrate the advantages of our method.     

Some problems in metric fixed point theory

Three papers, published coincidentally and independently by Felix Browder, Dietrich G?hde, and W. A. Kirk in 1965, triggered a branch of mathematical research now called metric fixed point theory. This is a survey of some of the highlights of that theory, with a special emphasis on some of the problems that remain open. Dedicated to Felix Browder on the occasion of his 80th birthday     

Preparation of high performance nanocomposite elastomer: effect of reaction conditions on in situ silica generation of high content in natural rubber

Effect of amines on an in situ silica generation in natural rubber was investigated, and n-hexylamine, n-heptylamine and n-octylamine were found to increase the in situ silica content. The nanometer sized silica particles up to ca. 80 parts per hundred rubber by weight were generated in situ in the rubber matrix via a sol–gel reaction of tetraethoxysilane. Additionally, dispersion of the silica in the rubbery matrix was more homogeneous than that of commercial silica dispersed by a conventional mechanical mixing. In this in situ silica generation, the polarity and solubility in water of amine were influential factors for controlling the in situ silica content in the rubbery matrix. The obtained high in situ silica filled natural rubber was useful to prepare high performance nanocomposite elastomers.     

Prediction of soluble solids content, firmness and pH of pear by signals of electronic nose sensors

The objective of this study was to investigate the predictability of an electronic nose for fruit quality indices. Responses signal of sensor array in electronic nose were employed to establish quality indices model for “xueqing” pear. The relationships were established between signal of electronic nose and the quality indices of fruit (firmness, soluble solids content (SSC) and pH) by multiple linear regressions (MLR) and artificial neural network (ANN). The prediction models for firmness and soluble solids content indicated a good prediction performance. The SSC model by ANN had a standard error of prediction (SEP) of 0.41 and correlation coefficient 0.93 between predicted and measured values, the model by ANN for the penetrating force (CF) had a 3.12 SEP and 0.94 coefficient, respectively. The results imply that it is possible to predict “xueqing” pear quality characteristics from signal of E-nose.     

不同产地地黄中地黄苷D的测定

应用高效液相色谱的方法建立了地黄苷D的定量分析。色谱条件:采用Hypersil C18柱(4.6 mmi.d.×250 mm,5μm),流动相:V(乙腈)∶V(水)=10∶90,流速:1 mL/min,检测波长205 nm,地黄苷D在0.059~0.295 mg/mL范围内呈良好线性关系,r=0.9999,回收率较高RSD=0.63%,对不同产地地黄的地黄苷D进行了定量分析,不同产地和不同等级的地黄中地黄苷D含量有较大差异,在使用中应加以考虑。     

The H2+ molecular ion: Low-lying states

Matching for a wavefunction the WKB expansion at large distances and Taylor expansion at small distances leads to a compact, few-parametric uniform approximation found in Turbiner and Olivares-Pilon (2011). The ten low-lying eigenstates of H₂⁺ of the quantum numbers (n,m,Λ,±)$(n,m,\Lambda ,\pm )$  with n=m=0$n=m=0$ at Λ=0,1,2$\Lambda =0,1,2$, with n=1$n=1$, m=0$m=0$ and n=0$n=0$, m=1$m=1$ at Λ=0$\Lambda =0$ of both parities are explored for all interproton distances R$R$. For all these states this approximation provides the relative accuracy ?10⁻⁵$?10^{-5}$ (not less than 5 s.d.) locally, for any real coordinate x$x$ in eigenfunctions, when for total energy E(R)$E\left(R\right)$ it gives 10-11 s.d. for R∈[0,50]$R\in [0,50]$  a.u. Corrections to the approximation are evaluated in the specially-designed, convergent perturbation theory. Separation constants are found with not less than 8 s.d. The oscillator strength for the electric dipole transitions E1$E1$ is calculated with not less than 6 s.d. A dramatic dip in the E1$E1$ oscillator strength f_{1sσg−3pσu}$f_{1s{\sigma }_g-3p{\sigma }_u}$ at R∼R_eq$R\sim R_{eq}$ is observed. The magnetic dipole and electric quadrupole transitions are calculated for the first time with not less than 6 s.d. in oscillator strength. For two lowest states (0,0,0,±)$(0,0,0,\pm )$ (or, equivalently, 1sσ_g$1s{\sigma }_g$ and 2pσ_u$2p{\sigma }_u$ states) the potential curves are checked and confirmed in the Lagrange mesh method within 12 s.d. Based on them the Energy Gap between 1sσ_g$1s{\sigma }_g$ and 2pσ_u$2p{\sigma }_u$ potential curves is approximated with modified Pade Re^−R[Pade(8/7)](R)$R{e}^{-R}\left[Pade(8/7)\right]\left(R\right)$ with not less than 4-5 figures at R∈[0,40]$R\in [0,40]$ a.u. Sum of potential curves E_1sσg+E_2pσu$E_{1s{\sigma }_g}+E_{2p{\sigma }_u}$ is approximated by Pade 1/R[Pade(5/8)](R)$1/R\left[Pade(5/8)\right]\left(R\right)$ in R∈[0,40]$R\in [0,40]$ a.u. with not less than 3-4 figures.     

Assessment of bone calcium and phosphorus content using micro X‐ray fluorescence spectrometry (μ‐EDXRF): effects of long‐term cadmium poisoning

This study assesses whether the concentrations of biologically important elements in bones are altered by long‐term consumption of cadmium (Cd)‐contaminated water. Heavy metal poisoning has significant impact on humans, and pollutants such as Cd are often found at high concentrations in waterways. Twelve Sprague Dawley rats consumed water with 50 p.p.m. Cd (Cd group), and another 12 consumed normal water (control group). Six subjects from each group were sacrificed after 2 weeks and the others after 4 weeks. Spectra were acquired from the femur by using the EDAX Eagle III micro‐XRF setup, and quantitative calculations were performed by using the fundamental parameter method to determine the concentrations of elements. A bone calcium/phosphorus concentration ratio (Ca/P) of 2.07 ± 0.001 is observed in the spectra from control subjects after 2 weeks and 2.07 ± 0.001 after 4 weeks. In Cd subjects, Ca/P after 2 weeks is 2.04 ± 0.001 and after 4 weeks is 1.97 ± 0.003. Statistically significant differences are obtained when comparing controls with Cd subjects at both time points and when comparing Cd subjects at both time points. Cadmium poisoning significantly affects bone Ca and P concentrations, increasing the likelihood of osteoporosis and other bone diseases. Copyright © 2016 John Wiley & Sons, Ltd.