高分辨率X射线显微成像及其进展

介绍了高分辨率X射线显微成像产生背景和发展过程，着重分析了基于光学元件波带片的放大成像的基本原理，并简述了高分辨率三维成像的有关理论。同时给出国内外高分辨率X射线显微成像研究的最新进展，展望了高分辨率X射线显微成像的应用前景。     

Standard molar enthalpy of formation of [(C12H8N2)2Bi(O2NO)3] and its biological activity on Schizosaccharomyces pombe

The title complex [(C₁₂H₈N₂)₂Bi(O₂NO)₃] was synthesized by reaction of 1,10-phenanthroline (phen) and Bi(NO₃)₃·5H₂O. The structure of the complex was characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analysis. An advanced solution-reaction isoperibol microcalorimeter was applied to determine the standard molar enthalpies of formation at 298.15 K of the complex and Bi(NO₃)₃·5H₂O, giving –(798.92 ± 5.99) and –(1986.87 ± 0.20) kJ mol⁻¹, respectively. The biological effect of the complex was evaluated by microcalorimetry on the growth of Schizosaccharomyces pombe (S. pombe). According to thermogenic curves, the corresponding thermokinetics and thermodynamic parameters were derived. The complex had good bioactivity on the growth metabolism of S. pombe, with the value of IC₅₀ being 2.8 × 10⁻⁵ mol L⁻¹.

     

量子相空间分布函数与压缩相干态表示间的变换关系

基于Husimi算符具有压缩相干态投影子形式, 首先介绍了一个新的量子算符表示, 即压缩相干态表示.当高斯展宽参数κ = 1时, 该函数约化为通常的P函数. 作为例子, 研究了热态的压缩相干态表示, 通过图示说明了压缩相干态表示与P函数的区别. 为更好地在量子光学问题中使用该表示, 我们揭示了压缩相干态表示与Wigner函数、Q函数以及Husimi函数间的积分变换关系.     

Yb5Ni4Sn10 and Yb7Ni4Sn13: New polar intermetallics with 3D framework structures

The title compounds have been obtained by solid state reactions of the corresponding pure elements at high temperature, and structurally characterized by single-crystal X-ray diffraction studies. Yb₅Ni₄Sn₁₀ adopts the Sc₅Co₄Si₁₀ structure type and crystallizes in the tetragonal space group P4/mbm (No. 127) with cell parameters of a=13.785(4) Å, c=4.492 (2) Å, V=853.7(5) Å³, and Z=2. Yb₇Ni₄Sn₁₃ is isostructural with Yb₇Co₄InGe₁₂ and crystallizes in the tetragonal space group P4/m (No. 83) with cell parameters of a=11.1429(6) Å, c=4.5318(4) Å, V=562.69(7) Å³, and Z=1. Both structures feature three-dimensional (3D) frameworks based on three different types of one-dimensional (1D) channels, which are occupied by the Yb atoms. Electronic structure calculations based on density functional theory (DFT) indicate that both compounds are metallic. These results are in agreement with those from temperature-dependent resistivity and magnetic susceptibility measurements.     

Observational Study of Annual Variations of the Surface Energy Balance Components at Zhongshan Station of Antarctica in 1990

From February 1990 to January 1991, the measurement experiment was carried out at Zhongshan station, East Antarctica. In the experiment, measurements of the surface radiative fluxes and wind, temperature and humidity profiles in the lowest 32 m in the atmosphere boundary layer were made throughout the year. The regime of the surface energy balance was analysed based on the observed data. The conclusion was derived that in warm season (from Nov. to Feb.), large amounts of energy are absorbed by the surface and then transported to the atmosphere in the form of sensible and latent heat, while in cold season (from Mar. to Oct.) continually radiative cooling of the surface occurs.     

Structures and physical properties of rare-earth zinc antimonides Pr6Zn(1+x)Sb(14+y) and RE6Zn(1+x)Sb14 (RE = Sm, Gd-Ho)

A new series of isostructural ternary rare-earth zinc antimonides RE(6)Zn(1+x)Sb(14+y) (RE = Pr, Sm, Gd-Ho) has been obtained by direct reaction of the elements at 1050-1100 degrees C. Single-crystal X-ray diffraction studies revealed that these compounds adopt an orthorhombic structure type (space group Immm (no. 71), Z = 2, a = 4.28-4.11 A, b = 15.15-14.73 A, c = 19.13-18.56 A in the progression from RE = Pr to Ho) that may be regarded as stuffed variants of a (U(0.5)Ho(0.5))(3)Sb(7)-type host structure. Columns of face-sharing RE(6) trigonal prisms, centered by Sb atoms, occupy channels defined by an extensive polyanionic Sb network. This network is constructed from three-atom-wide and four-atom-wide Sb strips, the latter being linked together by single Sb atoms in RE(6)Zn(1+x)Sb(14) (RE = Sm, Gd-Ho; y = 0), but also by additional Sb-Sb pairs in a disordered fashion in Pr(6)Zn(1+x)Sb(14+y) (y = approximately 0.6). Interstitial Zn atoms then partially fill tetrahedral sites (occupancy of 0.5-0.7) and, to a lesser extent, square pyramidal sites (occupancy of 0.04-0.12), accounting for the observed nonstoichiometry with variable x. Except for the Gd member, these compounds undergo antiferromagnetic ordering below T(N) < 9 K, with the magnetic susceptibilities of the Tb, Dy, and Ho members following the Curie-Weiss law above T(N). For the Ho member, the thermal conductivities are low and the Seebeck coefficients are small and positive, implying p-type character consistent with the occurrence of partial Zn occupancies. At low temperatures (down to 5 K), electrical resistivity measurements for the Tb, Dy, and Ho members indicated metallic behavior, which persists at high temperatures (up to 560 K) for the Ho member. Band structure calculations on an idealized "Gd(6)Zn(2)Sb(14)" model revealed the existence of a pseudogap near the Fermi level.     

原子吸收光谱法测定皖景天吸收镉和锌的研究

通过原子吸收光谱法研究了皖景天对镉和锌的吸收特性,结果表明:皖景天对镉和锌的吸收量随时间的延长而增加,皖景天对镉吸收速率随时间的延长而降低,皖景天对锌吸收速率随时间的延长呈现先下降后上升的趋势。     

In-phase alignments of asymmetric building units in Ln4GaSbS9 (Ln = Pr, Nd, Sm, Gd-Ho) and their strong nonlinear optical responses in middle IR

New noncentrosymmetric rare-earth metal gallium thioantimonates, Ln(4)GaSbS(9) were synthesized from stoichiometric element mixtures at 950 °C by high-temperature solid-state reactions. These compounds crystallize in orthorhombic space group Aba2 (no.41) with a = 13.799(3)-13.427(5) ?, b = 14.187(3)-13.756(5) ?, c = 14.323(3)-13.954(5) ?, V = 2804(2)-2577 (2) ?(3), and Z = 8 on going from Ln = Pr to Ho. The asymmetric building units, bimetallic polar (Sb(2)S(5)) units, and dimeric (GaS(4))(2) tetrahedra are in-phase aligned as an infinite single anionic chain of {[(Ga(2)S(6))(Sb(2)S(5))](10-)}(∞) that is further packed in a noncentrosymmetric pseudolayer motif perpendicular to the c axis. Three of the title compounds show large powder second harmonic generation (SHG) effects at 2.05 μm, and two of them also exhibit large transparency ranges (1.75 or 0.75 to 25 μm) in the middle-IR region. Significantly, the Sm-member exhibits the strongest SHG response among sulfides to date with intensity approximately 3.8 times that of the benchmark AgGaS(2). The band structures, indirect band gap nature, bonding strengths, and lone pair effects around Sb have also been studied by Vienna ab initio simulation package calculations.     

Structure change induced by terminal sulfur in noncentrosymmetric La2Ga2GeS8 and Eu2Ga2GeS7 and nonlinear-optical responses in middle infrared

Two new noncentrosymmetric quaternary sulfides, La(2)Ga(2)GeS(8) (1) and Eu(2)Ga(2)GeS(7) (2), have been synthesized by high-temperature solid-state reactions. The structure change on going from 1 to 2 to the known Li(2)Ga(2)GeS(6) (3) nicely shows that the reduced cation charge-compensation requirement causes a decrease in the number of terminal S atoms per formula, which is a key to determining the connectivity of the GaS(4) and GeS(4) building units. Powder sample 2 exhibits a strong second-harmonic-generation (SHG) response of about 1.6 times the benchmark AgGaS(2) at 2.05 μm laser radiation, a non type I phase-matchable behavior, and a comparable transparency region. The SHG intensities of these compounds originate from the electronic transitions from S 3p states to La/Eu/Li-S, Ga-S, and Ge-S antibonding states according to Vienna ab initio simulation package studies.