Adsorption of thorium(IV) on magnetic multi-walled carbon nanotubes

The influences of pH, contact time, solid-liquid ratio, temperature and C60(C(COOH)2)n on Th(IV) adsorption onto the magnetic multi-walled carbon nanotubes(MMWCNTs) were studied by batch technique. The dynamic process showed that the adsorption of Th(IV) onto MMWCNTs could reach equilibrium in 40 h and matched the pseudo-second-order kinetics model. The adsorption of Th(IV) onto MMWCNTs was significantly dependent on pH values, the adsorption ratio increased markedly at pH 3.0–5.0, and then maintained a steady state as pH values increased. At low pH, different C60(C(COOH)2)n content could enhance the adsorption content of Th(IV) onto MMWCNTs, but restrained it at higher pH. Through simulating the adsorption isotherms by Langmuir, Freundlich and Dubini-Radushkevich models, it could be seen respectively that the adsorption pattern of Th(IV) onto MMWCNTs was mainly surface complexation, and that the adsorption process was endothermic and irreversible.     

长玻纤母料增强聚丙烯研究

长玻纤增强聚丙烯复合材料被称为热塑性玻璃钢,由于具有较好的力学性能、成型工艺容易控制、易回收利用等特点,已经成为传统玻璃钢的替代产品。本文以聚丙烯作为基体,长玻纤母料作为增强相,加入相容剂以及其它助剂,制备可回收利用、满足环保要求的绿色复合材料,并对其拉伸、弯曲性能进行测试,进而得出长玻纤母料对聚丙烯的增强作用。研究结果表明:长玻纤母料与聚丙烯具有很好的相容性,能够错落有致地分布于聚丙烯基体中,达到很好的增强效果。     

Addendum to: Fabrication and characterization of graphene derived from SiC

<正>Addendum to:Science China:Physics,MechanicsAstronomy,2013,56(12):2386–2394doi:10.1007/s11433-013-5348-2The legends of the following Figures should be as follows:Figure 3 AFM morphologies and Raman spectra of a EG on a 2 inch SiC(0001)measured at five representative regions.(a)AFM Morphology reproduced from ref.[14]with permission from Science China Press and Springer publishing,(b)Raman spectra.Figure 6 SEM images of the VAGS.(a)Cross-section image of the VAGS;(b)and(c)are the top view images of the as-grown VAGS and the VAGS after top graphene layer removed reproduced from ref.[16]with permission from Wiley-VCH publishing.     

哈佛大学有效提升物理教学质量的举措分析

深入探讨了哈佛大学提升物理课程教学质量的举措,诸如卓越的教学方法、全面的教师培养、科学的教学指导、高效的教学评价等.哈佛大学的这些全面、细致、具体、实用的举措对我国大学物理教学质量的提升具有一定的借鉴意义.     

Phase-field modeling of void evolution and swelling in materials under irradiation

Void swelling is an important phenomenon observed in both nuclear fuels and cladding materials in operating nuclear reactors. In this work we develop a phase-field model to simulate void evolution and void volume change in irradiated materials. Important material processes, including the generation of defects such as vacancies and self-interstitials, their diffusion and annihilation, and void nucleation and evolution, have been taken into account in this model. The thermodynamic and kinetic properties, such...     

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采用球形托卡马克(ST)等离子体位形,对氦冷嬗变包层、钠冷嬗变包层、氟锂铍(FLiBe)熔盐冷嬗变包层三种嬗变包层中子学方案进行了初步计算分析,并就各自的中子学特性进行了比较.结果表明,从嬗变长寿命放射性锕系核素237Np的角度考量,FLiBe冷却嬗变包层的嬗变性能最优.对氦冷嬗变包层的计算结果表明,通过改变初装料时237Np在次锕系元素中的成分比例,可使包层在比较长的运行时间(9.62年)内,保持稳定有效增殖系数、稳定功率、稳定产氚率.     

火焰原子吸收光谱法测定饲料级硫酸盐中的铜

建立了火焰原子吸收光谱法测定饲料级硫酸盐中铜的方法,讨论了共存离子的干扰情况.在最佳实验条件下,该方法测定铜的特征浓度为0.019μg/mL,相对标准偏差为0.24％,样品加标回收率为99.2％-105.6％.被分析的饲料级硫酸盐中的共存离子对铜的测定基本无干扰.方法简便、快速,具有较高的准确度和精密度,适合用于饲料级硫酸盐中微量铜的测定.     

Two-dimensional coupled vibration and equivalent circuit of longitudinal-longitudinal orthogonal composite vibration direction converter

With the advantages of transmitting energy from multiple directions to one direction and transforming vibration from one source to multiple directions, the two-dimensional vibra?tion direction converter has important applications in power ultrasonic technology. However, for the complexity of using the wave equation to design and analysis the two-dimensional vibration direction converter, a concise equivalent circuit for the converter is investigated. By introducing the two-dimensional mechanical coupling coefficient and the longitudinal force transform coef?ficient, and using the electromechanical analogy principle, the equivalent circuit and resonance frequency equation of the two-dimensional vibration direction converter vibrating in anti-phase and in-phase two-dimensional coupled vibration are deduced. The resonance frequencies of the vibration direction converters of two different materials are calculated by using the proposed frequency equation, which are in agreement with the results from the finite element method and the experimental test. It provides a concise method for the design and applications of such ultrasonic vibration system.     

基于咔唑-靛红双-硫代碳酰腙衍生物的NMR研究

采用多种核磁共振（NMR）技术（包括¹H NMR、¹³C NMR、¹H-¹H COSY、¹H-¹³C HSQC、¹H-¹³C HMBC），对基于咔唑-靛红双-硫代碳酰腙新型衍生物2，即1-[（3Z）-2-氧代吲哚-3-亚基]-5-[（9-己基-3-咔唑基）亚基]硫代碳酰腙的¹H和¹³C NMR信号进行了全归属，确定了其结构．     

Photolyses of mammalian carboxy-hemoglobin studied by photoacoustic calorimetry

The enthalpy and conformational volume changes in the photolyses of carboxy-hemoglobin (HbCO) of human, bovine, pig, horse and rabbit are investigated by photoacoustic calorimetry. Considering the time scales of the exciting laser pulse and the receiving ultrasound transducers (PVDF films and PZT ceramics), as well as the reaction lifetimes in the photolysis processes of HbCO, the measured results are related to the geminate recombination and tertiary relaxation in photolyses of HbCO. Moreover, the quantum yields of the five mammals are also measured by laser pump-probe technique. The results show that the dynamic parameters, such as enthalpy and conformational volume changes, differ between the processes of the geminate recombination and tertiary relaxation. Also, the dynamic parameters differ among the five mammals although some of them may be consistent with each other.