A new hybrid target concept for multi-keV X-ray sources

A novel concept for using hybrid targets to create multi-keV X-ray sources was tested on the GEKKO XII facility of the OSAKA University and on the OMEGA facility of the University of Rochester. The sources were made via laser irradiation of a titanium foil placed at the end of a plastic cylinder, filled with a very low-density (2 and 5 mg/cm³) silicon-dioxide aerogel that was designed to control the longitudinal expansion of the titanium plasma. Preliminary calculations were used to determine optimal conditions for the aerogel density, cylinder diameter and length that maximize multi-keV X-ray emission. The X-ray emission power was measured on OMEGA using absolutely calibrated broad-band, diode-based CEA diagnostics, in addition to high resolution crystal spectrometers. On GEKKO XII, the heat wave propagation velocity in the aerogel was also measured with an X-ray framing camera. The advantage of using the thermal wave generated in the aerogel to heat a solid material to increase the conversion efficiency has not been fully demonstrated in these experiments. However, it was shown that a 5 mg/cm³ aerogel placed in front of a titanium foil can improve the x-ray conversion efficiency with respect to the case of 2 mg/cm³ for some target diameter and length.     

The absorption edge technique at the Super-EBIT

High temperature Mössbauer spectroscopy has been used for studying “in situ” the phase dynamics of the silicon rich part of the binary Fe-Si system. In particular the rate and mechanism of the transformation of the so-called zeta-alpha phase of iron disilicide to the zeta-beta phase is of special interest, since there still remains uncertainty about the stability and the structure of the phase in this system which influence material properties such as compressive strength and disintegration. In the present work the phase transition from the zeta-alpha phase to the zeta-beta phase is followed by a time sequence of Mössbauer spectra recorded every three hours at a fixed temperature around 800 K. The exponential precipitation rate is analysed and the exponent calculated. Samples with differing degree of impurities have been studied and the effect of aluminium impurities on the rate of the transition will be discussed. The Debye temperature of the two phases was determined from series of Mössbauer spectra recorded at temperatures between 300 and 800 K.     

Error Bounds for Hermite Interpolation by Quadratic Splines on an {alpha}-Triangulation

For l, an -triangulation F of a planar domain is such that,for every T F, there holds 1 R_T/2r_T , where R_T (resp. r_T)denotes the radius of the circumscribed (resp. inscribed) circleof the triangle T. When T is varying in F the centre of itsinscribed circle is varying in a compact interior to T and itsorthogonal projections on the sides are varying in compact intervalsinterior to these sides. Precise results are given about thesizes of these compacts and are used for the computation oferror constants in the problem of Hermite interpolation by Powell-Sabinquadratic finite elements, bringing to the fore their dependenceon the parameter .     

肉苁蓉精油化学成分的研究

肉苁蓉 Cistanche Salsa(C.A.Mey.)G.Beak 是列当科 Orobanchaceae 植物肉苁蓉的肉质茎;又名大芸,纵蓉。它分布在北疆地区荒漠戈壁地带,有益肾壮阳,延年益寿等功能,故有“沙漠人参”之称。肉苁蓉是一种常用的中药,新疆地区资源丰富,其精油化学成分在国内外未见报道。为了整理和发掘祖国医药学宝库,我们对其化学成分进行了研究。     

Calcium-selective electrode based on a calix[4]arene tetraphosphine oxide

A new ligand capable of producing calcium-selective electrodes with excellent characteristics is presented. The ligand (1) is a calix[4]arene bearing phosphine oxide ligating groups on the lower rim and this is the first report that such ligands can discriminate in favour of calcium ions against magnesium ions and the alkali metal ions. This calcium selectivity is in complete contrast to the behaviour of the well-known calix[4]arene tetraester derivatives (such as 2) which are selective for sodium against other alkali metal ions and group II ions. Electrodes based on PVC membranes incorporating ligand 1 display almost nernstian slopes and excellent selectivity against common interferants, including magnesium (log K(Ca,Mg)(pot)). The electrodes have demonstrated effective lifetimes of at least 7 weeks (duration of the study) and very fast response times.     

微波消解ICP-MS测定唐古特乌头中的多种微量元素

采用HNO3-H2O2混合酸体系微波消解及电感耦合等离子体-质谱法,消解唐古特乌头样品,测定其中Mn、Fe、Co、As、Ni、Se、Cu、Zn、V和Cr共10种微量元素。探讨了样品消解的条件,通过加标回收实验,回收率为94.08%—103.50%,验证了分析数据的可靠性。结果表明,该法具有快速、简便、准确度高、能同时分析多元素的优点,结果令人满意。