Natural widths and Coster–Kronig transitions of L X-ray spectra in elements between Pd and Sb

The Lα and Lβ X-ray emission spectra in the elements between Pd (Z=46) and Sb (Z=51) were measured using a high-resolution double-crystal vacuum spectrometer. The relative intensities of satellite structures, which originate in L₁L₃M_4,5 Coster–Kronig transitions, were estimated to that of each diagram line, and compared with calculated values. According to the work of Chen et al. [1977a. Theoretical L-shell Coster–Kronig energies 11⩽Z⩽103. At. Data Nucl. Data Tables 19, 97–151], Salgueiro et al. [1987. J. Phys. (Paris) 48 Colloq. C9, 609] and Vlaicu et al. [1998. Investigation of the 74W L emission spectra and satellites. Phys. Rev. A 58, 3544] L₁L₃M₄ Coster–Kronig transition is forbidden for 50⩽Z⩽77, and L₁L₃M₅ Coster–Kronig transition is forbidden for 50⩽Z⩽73. The results suggest that L₁L₃M_4,5 Coster–Kronig transitions may be allowed even for Sn (Z=50) and Sb (Z=51).     

Simulation of boron nitride sputtering process and its comparisonwith experimental data

In the paper, TRIM and TRIDYN simulation codes were used to simulate the sputtering processes of boron nitride (BN) films during bombardment of ions. The TRIM and TRIDYN codes are applicable to the simulation of sputtering processes of different target materials with amorphous and polycrystalline structure. The results of the simulations are compared with experimental data. The sputtering experiments of polycrystalline hexagonal BN (h-BN) and cubic BN (c-BN) films were performed in a Commonwealth Scientific Corporation (CSC) 38-cm ion beam source device. The comparison of calculated and experimental results indicated that a) the experimental sputtering yields of h-BN and c-BN films bombarded with Ar⁺ ions versus the angle of incidence are in reasonable agreement with the calculated results; b) the sputtering yields of h-BN and c-BN bombarded with Ar⁺ are nearly of the same values versus the angle of incidence-preferential sputtering of h-BN was not found; c) the calculated sputtering. Yields of BN as a function of Ar⁺ ion energy are very sensitive to values of the surface binding energy (SEE); and d) surface binding energy between 2 and 3 eV for BN appears to be reasonable for the simulation of sputtering process of h-BN and c-BN films     

Electrochemical impedance spectroscopic study of the rate-determining step of Li ion intercalation and deintercalation in LixNiO2 cathodes

The rate-determining step of the intercalation and deintercalation process of lithium ions in Li_xNiO₂ cathodes was studied by electrochemical impedance spectroscopic (EIS) analysis. EISs of the electrode process are composed of two semicircles. The higher frequency semicircle is related to the charge transfer resistance (R_ct) and the double layer capacitance (C_dl), while the lower frequency semicircle results from ion incorporation impedance (R_lattice) and space charge capacitance (C_sc). The assignment of the latter capacitance is discussed. It is found that R_lattice is 1000 times larger than R_ct. Accordingly, in most cases the ion incorporation into the lattice dominates the kinetic behavior. But for the ideal hexagonal phase, in the deintercalated state the Warburg impedance becomes important. As a result, the ion diffusion in the lattice is the rate-determining step. Paper presented at the 3rd Euroconference on Solid State Ionics, Teulada, Sardinia, Italy, Sept. 15–22, 1996     

关于(0,1)的对称和规范矩阵

给出更多的对于给定行和向量存在（０，１）对称矩阵的等价条件，同时也讨论了（０，１）规范矩阵的情形．     

Tunable diode laser spectroscopy of copper,cadmium, and indium at 325 nm

A tunable frequency-doubled external-cavity diode laser has been recently developed for atomic absorption spectroscopy in the wavelength range from 320 to 327 nm. The line width of the laser is 0.003 pm. In this work the light source has been applied to the laser absorption spectroscopy of copper at 324.754 nm, cadmium at 326.106 nm, and indium at 325.609 nm and 325.856 nm. The Cu transition was measured in three different environments: in a direct current plasma, a diffusion flame, and in a low-pressure hollow-cathode discharge. Both the plasma and the flame were at atmospheric pressure. The Cd and In transitions were measured in the diffusion flame. A Voigt profile was fit to the measured spectra taking into account the hyperfine structure. From the measured absorption lines spectral reference data for Cu is extracted.     

稀土(III)-冠醚配位反应的热力学性质: II. 镧系(III)高氯酸 盐与二苯并18- 冠-6在无水乙腈中配位反应的量热滴定研究

用滴定量热计于298.15K测定了除钷、镥以外的全部十三种镧系(III)高氯酸盐与二苯并-18-冠-6在无水乙腈中的配位作用。借助计算机用自编程序算出了配位反应的生成常数和焓变,进而算出了配位反应的自由能变化和熵变化。探讨了镧系(III)阳离子对配位反应的影响。此外,还比较了几种不同冠醚与高氯酸镧在无水乙腈中配位反应的热力学性质。     

Sound fields radiated from a linear phased array based on analytical solutions of transient elastic waves

Beam characteristics of a linear phased array transducer are critical to its engineering applications as well as to its design. This paper proposes a method for the theoretical calculation of ultrasound field radiated by a linear phased array coupled to an elastic solid by a longitudinal wave couplant. In this case, the ultrasound field can be determined by superposition of the exact and analytical solutions of transient elastic waves induced by a number of discrete line sources normally acting on an elastic half-space. Based on the theoretical calculation, this work investigated the influences of several important parameters in a linear array transducer, such as wave length, array size, ratio of element width to inter-element spacing, to the ultrasound field characteristics. Interesting phenomena and useful results are obtained, which provide fast and accurate guidance for linear phased array transducer design. It also satisfies diverse and specific demands for actual engineering testing using arrayed transducers.     

Interactions between model inclusions on closed lipid bilayer membranes

Protein inclusions in the membranes of living cells interact via the deformations they impose on that membrane. Such membrane-mediated interactions lead to sorting and self-assembly of the inclusions, as well as to membrane remodelling, crucial for many biological processes. For the past decades, theory, numerical calculations and experiments have been using simplified models for proteins to gain quantitative insights into their behaviour. Despite challenges arising from nonlinearities in the equations, the multiple length scales involved and the nonadditive nature of the interactions, recent progress now enables for the first time a direct comparison between theoretical and numerical predictions and experiments. We review the current knowledge on the biologically most relevant case, inclusions on lipid membranes with a closed surface and discuss challenges and opportunities for further progress.     

全概率公式的推广与应用

认为全概率公式成立的条件＂事件组须为样本空间的划分＂可以减弱,给出全概率公式在有限事件组情形和无限可列事件组情形下的两种推广形式,由此对贝叶斯公式进行两种相应推广,并通过实例展示全概率公式在敏感性调查中的应用.     

Impact of landuse change on the molecular composition of soil organic matter

The conversion of grassland into cultivated land is a common agricultural practice, generally leading to the decrease of the soil organic matter (SOM) content. In this study, we analysed quantitative changes in carbon content. Additionally qualitative changes occurring in the soil organic matter composition on a molecular basis were assessed using Curiepoint pyrolysis coupled to gas chromatography and mass spectrometry (pyrolysis GC/MS). The aim of the study was to follow the development of SOM in grassland soil, after conversion into arable soil.Soil was sampled before the conversion (0 month) as well as 3 months, and 1 year after the conversion. The samples were treated with 10% HF to remove mineral material before being subjected to analysis of the bulk chemical composition by pyrolysis GC/MS. The relative contributions of single molecules were obtained by the integration of the total ion chromatogram.Pyrolysis products derived from lignins, proteins and polysaccharides were identified in all samples. SOM under grassland, arable land and converted grassland released similar pyrolysis products. Three months after the conversion, lignin-derived pyrolysis products were found at lower concentrations in the converted grassland soil. Principal component analysis showed that arable land, grassland and the converted grassland could be distinguished using the score plot of the 2nd and 3rd principal components. The differences induced by grassland conversion are only transitory and 1 year after the conversion, SOM has a similar composition as SOM of the initial grassland soil.