美罗培南及其保护体的核磁共振波谱研究

美罗培南（Meropenem）为第二代碳青霉烯类抗生素，具有非常广泛的抗菌活性，用于治疗多种感染，为一线治疗药物. 该文运用一维和二维核磁共振(NMR)波谱对美罗培南及其保护体(protected meropenem)的¹H和¹³C NMR信号进行了全归属和解释，纠正了文献\[5\]中对美罗培南的C-6和C-7的归属错误，并探讨了美罗培南保护体中由于对硝基苄基的引入使得酰胺键旋转更加困难而产生的旋转异构现象.     

Study of coals by high resolution solid state nuclear magnetic resonance

By using high resolution solid state nuclear magnetic resonance method, six coal samples coming from four countries were investigated. Twelve structural parameters of these samples were measured and compared withthose of Chinese coals. Spectral editing experiment was carried out and¹⁵N NMR spectrum was obtained. Project supported by the National Natural Science Foundation of China (Grant No. 19774068)and the NEDO’s International Joint Research Program of Japan.     

Hyperfine structure of Li like bismuth

The hyperfine structure of lithium-like ²⁰⁹Bi⁸⁰⁺ was calculated in the dynamic-correlation model and compared with other theoretical results. The values obtained within this model are considerably smaller than those obtained in perturbation calculations. This revised version was published online in August 2006 with corrections to the Cover Date.     

Electronic and magnetic studies of materials to megabar pressures

Numerous recent developments in diamond-cell techniques are making possible a growing range of studies of the electronic and magnetic properties of materials to megabar pressures. We review recent advances in this area, including magnetic susceptibility, electrical conductivity, and synchrotron-based spectroscopic techniques. Highly sensitive magnetic susceptibility techniques have allowed the first observations of superconductivity at megabar pressures, including the observation of a T_c of 17 K in sulfur at 160 GPa, and a nearly pressure-independent T_c to above 230 GPa. The technique has recently been extended to allow measurements of the magnetic properties of ferromagnetic substances. Advances in the direct measurement of electrical conductivity using miniaturized leads have permitted measurements on H₂O and Xe to above 100 GPa. Pressure-induced high-spin to low-spin transitions have been examined in FeS and FeO using new high-resolution X-ray emission techniques. New high-pressure inelastic scattering methods, including nuclear inelastic scattering techniques, have been used to determine the phonon density of states of Fe to above 150 GPa. This revised version was published online in July 2006 with corrections to the Cover Date.     

绿豆(Vigna Radiata)代谢物组成的核磁共振定量分析

绿豆(Vigna radiata)是重要的经济作物之一,具有抗氧化、抗炎和抗菌作用.然而迄今为止,绿豆代谢物组成信息仍不完善.为了系统地定量研究绿豆代谢物组成,该研究利用DOSY,J-RES,COSY,TOCSY,HSQC,HMBC和1D 1H NMR谱图在鄂绿4号(ElüNo.4)绿豆水相提取物中鉴定和归属了48种代谢物,确定了绿豆中棉籽糖家族寡糖的构成,并且利用全弛豫谱对其中44种代谢物进行了定量分析.     

Thallium hyperfine anomaly

Measurements of the hyperfine structure in the highly charged hydrogen like systems ²⁰³Tl⁸⁰⁺ and ²⁰⁵Tl⁸⁰⁺ are underway at the Super EBIT at LLNL. This work considers the effects of the nuclear magnetization distribution on the hyperfine structure. The difference in energy splitting due to hyperfine structure for ²⁰³Tl and ²⁰⁵Tl, respectively, is found to be 0.031 04(1) eV, which corresponds to a transition wavelength difference of 3.640(1) nm. This revised version was published online in August 2006 with corrections to the Cover Date.     

Matter-induced ω→ππ decay

We calculate the width for the ω→ππ decay in nuclear matter in a hadronic model including mesons, nucleons and Δ isobars. We find a substantial width of the longitudinally polarized ω modes, reaching ∼100 MeV for mesons moving suitably fast with respect to the nuclear medium. Received: 7 June 1999 / Revised version: 14 October 1999     

Sodium-23 MAS NMR study on nuclear quadrupole interaction in Na1−xAgxNO2

Ag-impurity effects on the first- and second-order quadrupole interaction (QI) at ²³Na site in an isomorphic mixed system, Na_1−xAg_xNO₂ (x=0, 0.0084, 0.026, 0.079, 0.094, 0.16), have been investigated by employing ²³Na (I=3/2) magic angle spinning nuclear magnetic resonance (MAS NMR) technique. The central transition (CT) and satellite transition (ST) are simultaneously observed with this system. From the spectral analysis, the quadrupole parameter and its distribution width are obtained as a function of Ag concentration. From the intensity loss of CT MAS centerband and of the envelope function of ST MAS sidebands due to impurities, the range of their influence on the second- and first-order QI is estimated. The estimated ranges contain the second and first neighbouring Na sites from the resonating ²³Na nucleus for the first- and second-order QI, respectively.     

Selectivity assessment of an arsenic sequential extraction procedure for evaluating mobility in mine wastes

An optimized sequential extraction (SE) scheme for mine waste materials has been developed and tested for As partitioning over a range of pure As-bearing mineral phases, their model mixtures, and natural mine waste materials. This optimized SE procedure employs five extraction steps: (1) nitrogen-purged deionized water, 10 h; (2) 0.01 M NH₄H₂PO₄, 16 h; (3) 0.2 M NH₄-oxalate in the dark, pH3, 2 h; (4) 0.2 M NH₄-oxalate, pH3/80 °C, 4 h; (5) KClO₃/HCl/HNO₃ digestion. Selectivity and specificity tests on natural mine wastes and major pure As-bearing mineral phases showed that these As fractions appear to be primarily associated with: (1) readily soluble; (2) adsorbed; (3) amorphous and poorly-crystalline arsenates, oxides and hydroxosulfates of Fe; (4) well-crystalline arsenates, oxides, and hydroxosulfates of Fe; as well as (5) sulfides and arsenides. The specificity and selectivity of extractants, and the reproducibility of the optimized SE procedure were further verified by artificial model mineral mixtures and different natural mine waste materials. Partitioning data for extraction steps 3, 4, and 5 showed good agreement with those calculated in the model mineral mixtures (<15% difference), as well as that expected in different natural mine waste materials. The sum of the As recovered in the different extractant pools was not significantly different (89–112%) than the results for acid digestion. This suggests that the optimized SE scheme can reliably be employed for As partitioning in mine waste materials.