类He离子的电子碰撞激发截面

利用扭曲波方法计算类He离子的电子碰撞激发截面。靶波函数采用HFS自洽场波函数,本文计算了若干元素从基态(1¹S)到2¹S,2¹P,2³S,2³P的跃迁。计算结果以碰撞强度的形式给出。入射电子能量从激发阈能开始到x=10,计算结果与已有的结果作了比较,分析表明,在大多数情况下,结果是满意的。     

Density versions of Schur's theorem for ideals generated by submeasures

We characterize ideals of subsets of natural numbers for which some versions of Schur's theorem hold. These are similar to generalizations shown by Bergelson (1986) in [1] and Frankl, Graham and Rödl (1990) in [7]. Additionally, we prove a generalization of an iterated version of Ramsey's theorem.     

INFLUENCE OF SHAMPOO ON THE MECHANICAL PROPERTIES OF HUMAN HAIRS1)

头发的弹性和抵抗意外拉断的能力是人们非常关注的指标。为了迎合这一需求,有些厂商推出了具有所谓“强韧”发质功效的洗发水,但其实并不清楚是否真能使头发变“强韧”。为此,针对市场上常见的一种标称具有“强韧”功效的洗发水,通过拉伸力学实验对头发洗护前后的力学性能进行了对比研究。结果表明,用洗发水处理后的头发,屈服应力下降,意味着头发更容易过早进入塑性变形;抗拉强度、最大应变减小,意味着头发抵抗外力拉断的能力下降;杨氏模量下降,说明头发抵抗弹性变形的能力变差。综上,所研究的洗发水对“强韧”发质没有帮助。 关键词: 头发,洗发水,力学性能,强度,韧性     

The role of the bubble–bubble interaction on radial pulsations of bubbles

Using a model that with or without considering the interaction between bubbles through the radiated pressure waves, numerical simulations of cavitation bubbles have been performed in order to study the effect of the bubble–bubble interaction on radial pulsations of bubbles. Comparing the results obtained by with or without considering the bubble–bubble interaction, it is suggested that the suppression or enlargement property of expansion ratios of bubbles due to the bubble–bubble interaction largely depends on the ultrasound parameters, the ambient bubble radii, the distances between bubbles and the number of bubbles (in multi-bubble environment, the last two aspects can be expressed using the coupling strength). The frequency response curve of expansion ratio decreases and shifts to left due to the bubble–bubble interaction and the larger the coupling strength is, the more the left-shifting is.     

Characterizations of Strongly Regular Rings

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简支矩形复合材料薄板压缩屈曲后的极限强度

本文通过283块简支矩形玻璃钢薄板的压缩屈曲后极限强度的试验,证明了复合材料薄板在屈曲失稳后仍能继续承载,以玻璃钢为例,可以超过临界载荷的十几倍。文中对薄板的极限强度进行了大挠度和小挠度理论分析,结合复合材料的能量强度理论,最后得出有关极限强度计算公式的C参数曲线,对于45°方向的薄板与试验结果较符合,对于经纬向薄板当β<0.11时比试验结果略大。文中给出的C参数可供产品设计时参考。     

Comparing and ranking fuzzy numbers using ideal solutions

This paper presents a new approach for comparing and ranking fuzzy numbers in a simple manner in decision making under uncertainty. The concept of ideal solutions is sensibly used, and a distance-based similarity measure between fuzzy numbers is appropriately adopted for effectively determining the overall performance of each fuzzy number in comparing and ranking fuzzy numbers. As a result, all the available information characterizing a fuzzy number is fully utilized, and both the absolute position and the relative position of fuzzy numbers are adequately considered, resulted in consistent rankings being produced in comparing and ranking fuzzy numbers. The approach is computationally simple and its underlying concepts are logically sound and comprehensible. A comparative study is conducted on the benchmark cases in the literature that shows the proposed approach compares favorably with other approaches examined.     

Optimizing gradient conditions in online comprehensive two‐dimensional reversed‐phase liquid chromatography by use of the linear solvent strength model

The linear solvent strength model was used to predict coverage in online comprehensive two‐dimensional reversed‐phase liquid chromatography. The prediction model uses a parallelogram to describe the separation space covered with peaks in a system with limited orthogonality. The corners of the parallelogram are assumed to behave like chromatographic peaks and the position of these pseudo‐compounds was predicted. A mix of 25 polycyclic aromatic compounds were used as a test. The precision of the prediction, span 0–25, was tested by varying input parameters, and was found to be acceptable with root mean square errors of 3. The accuracy of the prediction was assessed by comparing with the experimental coverages. Less than half of experimental coverages were outside prediction ± 1 × root mean square error and none outside prediction ± 2 × root mean square error. Accuracy was lower when retention factors were low, or when gradient conditions affected parameters not included in the model, e.g. second dimension gradient time affects the second dimension equilibration time. The concept shows promise as a tool for gradient optimization in online comprehensive two‐dimensional liquid chromatography, as it mitigates the tedious registration and modeling of all sample constituents, a circumstance that is particularly appealing when dealing with complex samples.     

Speciation of phytate ion in aqueous solution. Cadmium(II) interactions in aqueous NaCl at different ionic strengths

Interactions between myo-inositol 1,2,3,4,5,6-hexakis(dihydrogen phosphate) (phytic acid) and cadmium(II) were studied by using potentiometry (at 25 °C with the ISE-H⁺ glass electrode) in different metal to ligand (Phy) ratios (1:1≤Cd²⁺:Phy≤4:1) in NaCl_aq at different ionic strengths (0.1≤I/mol L⁻¹≤1). Nine Cd_iH_jPhy^{(12−2i−j)−} species are formed with i=1 and 2 and 4≤j≤7; and trinuclear Cd₃H₄Phy²⁻. Dependence of complex formation constants on ionic strength was modeled by using Specific ion Interaction Theory (SIT) equations. Phytate and cadmium speciation are also dependent on the metal to ligand ratio. Stability of Cd_iH_jPhy^{(12−2i−j)−} species was modeled as a function of both the ligand protonation step (j) and the number of metal cations bound to phytate (i), and relationships found were used for the prediction of species other than those experimentally determined (mainly di- and tri-protonated complexes), allowing the possibility of modeling Phy and Cd(II) behavior in natural waters and biological fluids. A critical evaluation of phytate sequestering ability toward cadmium(II) has been made under several experimental conditions, and the determination of an empirical parameter has been proposed for an objective “quantification” of this ability. A thorough analysis of literature data on phytate–cadmium(II) complexes has been performed. Previous contributions to this series: [1–8]     

Intramolecular hydrogen bonding in 3‐imino‐propenylamine: Theoretical investigations

Intramolecular H‐bonds existing for derivatives of 3‐imino‐propenylamine have been studied using the B3LYP/6‐311++G** level of theory. The nature of these interactions, known as resonance‐assisted hydrogen bonds, has been discussed. Vibrational frequencies for α‐derivatives were calculated at the same level of theory. The topological properties of the electron density distributions for N? H···N intramolecular bridges have been analyzed in terms of the Bader theory of atoms in molecules (AIM). Calculation for 3‐imino‐propenylamine derivatives in water solution were also carried out at B3LYP/6‐311++G** level of theory. Finally, the analysis of hydrogen bond in this molecule and their derivatives by quantum theory of natural bond orbital methods fairly support the ab initio results. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009