次线性不对称Duffing 方程的Aubry-Mather 集

本文通过引进合适的作用— 角变量变换并结合新的估计方法, 对次线性不对称Duffing 方程的Poincaré 映射应用推广的Aubry-Mather 定理, 获得了一类次线性不对称Duffing 方程的Aubry-Mather 集存在的充分性条件.     

In situ annealing effects on magnetic properties and variable-range hopping of iron-based ladder material BaFe2S3

正All iron-based superconductors,regardless of their detailed crystal structure,share the same conductive Fe_2X_2(X=As,P,Se,and S)layers as the crucial structural unit[1-8].In the Fe_2X_2 layers,edge-shared FeX_4 tetrahedra form a square lattice in quasi-two-dimensional(quasi-2D)planes.One may wonder what kind of properties will be manifested in the quasi-one-dimensional(quasi-1D)counterparts exhibiting an identical coordination as the above-mentioned quasi-2D     

Synthesis of OMeTAD and TAD

Hole transport materials are currently researching hot topic and are paid more and more attention to by a lot of scientists.     

Electron cooling experiments in CSR

The six species heavy ion beam was accumulated with the help of electron cooling in the main ring of Cooler Storage Ring of Heavy Ion Research Facility in Lanzhou (HIRFL-CSR). The ion beam accumulation dependence on the parameters of cooler was investigated experimentally. The 400 MeV/u ¹²C⁶⁺ and 200 MeV/u ¹²⁹Xe⁵⁴⁺ were stored and cooled in the experimental ring CSRe, and the cooling force was measured in different conditions.

     

同步辐射的医学应用

介绍了同步辐射心血管造影术,计算机断层扫描术,肺部支气管成像术,乳腺成像术,辐射治疗等医学活体诊断和治疗技术的原理,应用现状以及近年来国际上各同步辐射实验室医学应用的发展情况。     

Preface

As a kind of molecular materials that have infinite metalligand backbones connected by coordination bonds,owing to the diversity of organic bridging ligands and flexibility of metal ions and organic bridging ligands in coordination     

Thermal expansion behaviors of Mn(Ⅱ)-pyridylbenzoate frameworks based on metal-carboxylate chains

Solvothermal reactions of MnCl₂ with pyridylbenzoic acids gave three-dimensional metal-carboxylate frameworks (MCFs), named MCF-34, MCF-43, and MCF-44, based on one-dimensional Mn-carboxylate chains. The crystal structure, stability, porosity, and framework flexibility of the new compound MCF-44 were studied in detail and compared with its analogs. Depending on their shapes and the bridging angles of the ligands, these compounds possess different network connectivities and porosities. Considering the pyridylbenzote ligands and Mn(II) ions as, respectively, 3- and 6-connected nodes, they resemble either the anatase (ant) or rutile (rtl) polymorph of TiO₂. Variable-temperature single-crystal X-ray diffraction studies revealed large thermal expansion coefficients for these compounds, which are probably related to the relatively flexible edge-sharing polyhedral structure of their Mn-carboxylate chains. Interestingly, the new compound MCF-44, with its highly porous rtl structure exhibits the largest thermal expansion coefficienct among the coordination polymers reported so far.     

Helical nanostructure of tubular metal-organic complex synthesized by sonochemical process

Tubular metal-organic complex (C2H9N2)2(C2H10N2)0.5[MoO2(OC6H4O)2] has been synthesized. The title complex crystallizes in the tetragonal system, space group P4(2)/n with a = 25.214(8), c = 7.484(4) ?, and Z = 8. The X-ray structural analysis of the complex reveals tube-like framework which is stabilized by hydrogen bond. Chiral anions [Mo(V)O2(OC6H4O)2]3? of the complex have two types of isomers(λ /δ configuration). Helical nanostructure of this metal-organic complex was formed using a sonochemical method. Sonocation may lead to the transformation from the bulk tubular complex to the helical nanostructure. The as-synthesized nanohelices were all double-stranded and left- and right-handed nanohelices were both formed. The helical nanostructure is a new morphology of inorganic-organic hybrid materials on the nanoscale level and the exact formation mechanism of these helices still needs further investigation.     

Unusual one-way edge state in acoustic gyroscopic continuum

Unusual one-way edge states have been observed in composite structures composed of periodic lattices loaded with gyroscopes.Here, we provide a continuum-mechanics understanding to the one-way edge state by formulating surface state equations of acoustic gyroscopic mediums with Hermite mass density tensor. We discover that the unidirectional edge effect arises from nontrivial off-diagonal components of Hermite densities, which causes the symmetric breaking of surface wave propagation towards forward and backward directions. Theoretical predictions on the velocity and decay length of surface waves coincide excellently with numerical simulations. The unidirectional edge state in a two-interface gyroscopic medium is also analyzed.Due to the rotational symmetry in geometry, the unidirectional edge state on one interface is able to prevent itself from the coupling to surface waves on the other interface regardless of the slab thickness. With these anomalous effects, surface waves residing on gyroscopic mediums can flow around the edge defects without back-scatterings, or can be split into two beams of equal energy magnitudes. Our findings may make a bridge that would help to reach the design of non-reciprocal composite materials via an effective medium approach.     

Diversity-oriented synthesis of bicyclic ring systems via a conjugate addition/aldol/RCM process

Diversity-oriented synthesis(DOS) has been widely applied in the generation of a large collection of highly functionalized molecules with diverse chemical skeletons.Herein,we report the diversity-oriented synthesis of a series of structurally diverse bicyclic substrates via an efficient tandem conjugate addition/aldol process followed by ring-closing metathesis(RCM).This approach allows us to efficiently prepare a number of structurally complex molecules for the further chemical biology studies.