Determination of Salidroside in Medicinal Plants Belonging to the Rhodiola L. Genus Originating from the Qinghai–Tibet Plateau

The Rhodiola L. genus (Crassulaceae) is one of the most important medicinal plant products used by Tibetans in Chinese phytotherapy. Fourteen species were examined for their content of salidroside. A considerable quantitative variation was observed using high-performance liquid chromatography and this depended on species and regional factors. It was found that all samples contained salidroside at concentrations ranging between 0.02 mg g^?1 (R. sinuate) and 15.95 mg g^?1 (R. sacra), respectively. The content of salidroside in R. sacra was significantly higher than in other popular medicinal plants of this genus. This finding indicated that there may be more Rhodiola species present in the Qinghai–Tibet Plateau which may be used as a potential source of salidroside.     

相对论重离子反应的热化过程

本文从相对论BUU理论出发研究了1GeV/n能区重离子反应全局(global)和局域(local)平衡性质,计算表明在该能区平均场对反应动力学过程仍有相当的作用;对有限核系统的反应动力学过程的时间演化的研究表明,有限核系统无论全局的还是局域的平衡均未能达到完全平衡,因而对有限核系统重离子反应基于完全热平衡概念的适用性值得怀疑.     

Study of uranium isotope separation using CO2 laser and CO laser

First, the kinetic investigation of UF₆ + HCl reaction and the isotopic selectivity under CO laser irradiation is performed. On this investigation, the kinetics of UF₆ + HCl reaction by using an intracativity CO laser and CO₂ laser irradiation system, and the isotopic selectivity for this process are studied theoretically. It is found that under the resonant CO laser and CO₂ laser irradiations, the laser-catalyzed reaction rate can increase, and a good selectivity can be achieved. The uranium isotope separation factors β calculated are about 2.44 ∼ 4.05 at laser intensity 50 ∼ 100 W cm⁻² and temperature 235 K.     

Swelling Properties and Environmental Responsiveness of Superabsorbent Composite Based on Starch-G-Poly Acrylic Acid/Organo-Zeolite

Star-g-poly (acrylic acid)/organo-zeolite 4A (S-g-PAA/OZ) superabsorbent composite was prepared by grafting partially neutralized acrylic acid onto starch in the presence of organo-zeolite 4A (OZ) as an inorganic component. The morphology was characterized with scanning electron microscopy (SEM). Energy dispersive spectrometer (EDS) analysis revealed the fine distribution of OZ in superabsorbent composite. The swelling kinetics of the composites were characterized by means of a Schott's second-order model. The effect of OZ concentration in the composite on the water absorbency and swelling behavior were tested. The swelling properties of the composites were evaluated in various environments; pH, salinity, temperature, urea solution, and solvent-water mixtures. The activation energy (ΔE) for water during the swelling process was also determined through Arrhenius plots. The results showed that the proper amount of OZ was beneficial for improvement of the water absorbent capacity and the initial swelling rate in distilled water. The optimum prepared composite with 10 wt % OZ, possessed the maximum water absorption (511g/g) in distilled water and (521 g/g) in 0.1 wt % urea solution. The results inferred that S-g-PAA/OZ superabsorbent composite can be exploited for agriculture and medical applications.     

Convenient synthesis of highly functionalized pyrazolines via mild, photoactivated 1,3-dipolar cycloaddition

A mild, photoactivated 1,3-dipolar cycloaddition procedure was successfully developed for the synthesis of polysubstituted pyrazolines. This procedure involved the in situ generation of the reactive nitrile imine dipoles using a hand-held UV lamp at 302 nm, followed by spontaneous cycloaddition with a broad range of 1,3-dipolarophiles with excellent solvent compatibility, functional group tolerance, regioselectivity, and yield.     

离心压缩机叶轮三维有限元强度分析系统

根据离心压缩机叶轮形状的特点,通过有效的网格自动划分和边界条件的处理,采用三维有限元方法进行了强度计算与分析,从而建立了离心叶轮三维有限元强度分析系统。对于叶轮与主轴之间的过盈配合,求出配合处由于变形而产生的弹性支力,以载荷形式施加于配合之处,由于计算时不加入主轴,从而减少了一,通过等厚度圆尖力的计算验证了有限元程序的可靠性,最二,对一个实际的三元流叶轮进行了计算,通过编制的后处理软件,对影响叶轮     

Temperature-Dependent Imaginary Part of the Off-Shell Nucleon Self-Energy and the Second Order Correction of Real Part of the Nucleon Self-Energy

The imaginary part of the off-shell nucleon self-energy at finite temperature in nuclear matter, where the polarization and correlation contributions of exchanges of the meson are taken into account, is investigated based on Walecka's meson-nucleon model and thermofield dynamics. The second order correction of temperature-dependent real part of the nucleon self-energy is calculated in terms of the dispersion relation. The Schrodinger equivalent potential of relativistic microscopic optical potential of a nucleon at finite temperature in nuclear medium is also studied.     

Raman and IR spectroscopy study of corrosion products on the surface of the hot‐dip galvanized steel with alkaline mud adhesion

The corrosion products formed on hot‐dip galvanized steel sheets for the automobile application with adhesion of alkaline mud containing different Cl⁻ ion contents are investigated by means of Raman and infrared (IR) spectroscopy. Results show that the Cl⁻ ion content in alkaline mud has great influence on the corrosion behavior of the galvanized steel. The Cl⁻ ions are responsible for the formation of the Zn₅Cl₂(OH)₈· H₂O layer on the surface of the steel at the early stage of corrosion. The rest of the Cl⁻ ions then penetrate and interrupt corrosion product layer resulting in pitting corrosion. Subsequently, the red corrosion product of α‐FeOOH (shaped as needle‐like structure) is formed, which then transforms into black rust of Fe₃O₄ (having a shape of slim needle). It is interesting to find out that pitting depth is inversely proportional to the Cl⁻ ion content. However, corrosion rate decreases with the increase of the Cl⁻ ions in mud. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of gas pressure on ionization of ambient gas

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One-step solvothermal synthesis of single-crystalline TiOF2 nanotubes with high lithium-ion battery performance

Single-crystalline TiOF(2) nanotubes were prepared by a one-step solvothermal method. The nanotubes are rectangular in shape with a length of 2-3?μm, width of 200-300?nm, and wall thickness of 40-60?nm. The formation of TiOF(2) nanotubes is directly driven by the interaction between TiF(4) and oleic acid in octadecane to form the 1D nanorods, and this is followed by a mass diffusion process to form the hollow structures. The synthesis approach can be extended to grow TiOF(2) nanoparticles and nanorods. Compared with TiO(2), which is the more commonly considered anode material in lithium-ion batteries, TiOF(2) has the advantages of a lower Li-intercalation voltage (e.g., to help increase the total voltage of the battery cell) and higher specific capacities. The TiOF(2) nanotubes showed good Li-storage properties with high specific capacities, stable cyclabilities, and good rate capabilities.