两个具有Sn_4O_4梯状结构二丁基锡羧酸酯的微波溶剂热合成、结构和体外抗癌活性

在甲醇微波溶剂热中,二丁基氧化锡分别与4-甲基苯甲酸、4-二甲氨基苯甲酸反应,合成了2个具有梯形结构的二丁基锡羧酸酯[(μ3-O)(μ2-OMe)(n-Bu2Sn)2(O2CR)]2(R=4-Me-C6H4(1),4-Me2N-C6H4(2)),并对其进行了元素分析、IR和(1H,13C和119Sn)NMR光谱表征。X射线晶体衍射分析表明,化合物1、2具有Sn4O4构筑的3个四元环梯形骨架平面结构,μ3-O桥联2个环内梯锡和1个环梯端锡原子,此外,甲醇氧还以μ2-O桥联1个环内梯锡和1个环梯端锡原子,锡与配基原子构成畸形三角双锥六面体。化合物对人结肠癌(HT-29)、肝癌细胞(Hep G2)、乳腺癌(MCF-7)、鼻咽癌(KB)和肺癌细胞(A549)均显示出比临床使用的顺铂还强的抗癌活性。     

APPLICATION OF VARIABLE-FIDELITY MODELS TO AERODYNAMIC OPTIMIZATION

For aerodynamic shape optimization, the approximation management framework (AMF) method is used to organize and manage the variable-fidelity models. The method can take full advantage of the low-fidelity, cheaper models to concentrate the main workload on the low-fidelity models in optimization iterative procedure. Furthermore, it can take high-fidelity, more expensive models to monitor the procedure to make the method globally convergent to a solution of high-fidelity problem. Finally, zero order variable-fidelity aerodynamic optimization management framework and search algorithm are demonstrated on an airfoil optimization of UAV with a flying wing. Compared to the original shape, the aerodynamic performance of the optimal shape is improved. The results show the method has good feasibility and applicability.     

基于金属有机骨架材料Tb-BTC显现潜指印的研究

为探究金属有机骨架材料在指印显现领域的应用,本研究采用预混合迅速滴显的方法,使金属有机骨架材料Tb-BTC直接络合在指印纹线上.使用该材料对渗透性客体中A4纸、黑色卡纸、牛皮纸;非渗透性客体中透明玻璃片、瓷砖上的皮脂指印进行显现,探究了不同配比、不同滴加顺序、不同显现时间的预混合溶液对不同类型、不同遗留时间、不同遗留物...     

Boron-doped Covalent Triazine Framework for Efficient CO2 Electroreduction

Converting CO₂ into chemicals with electricity generated by renewable energy is a promising way to achieve the goal of carbon neutrality. Carbon-based materials have the advantages of low cost, wide sources and environmental friendliness. In this work, we prepared a series of boron-doped covalent triazine frameworks and found that boron doping can significantly improve the CO selectivity up to 91.2% in the CO₂ electroreduction reactions(CO₂RR). The effect of different doping ratios on the activity by adjusting the proportion of doped atoms was systematically investigated. This work proves that the doping modification of non-metallic materials is a very effective way to improve their activity, and also lays a foundation for the study of other element doping in the coming future.     

Observation of ZnO nanoparticles outside pores of nano Zn4O(C8H4O4)3 metal-organic framework

It was recognized that ZnO can be formed during synthesizing nano Zn₄O(C₈H₄O₄)₃ metal-organic framework (nano MOF-5). Furthermore, it is generally accepted that the ZnO is dispersed inside the pores of MOF-5. However, herein, the measurements of X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) showed that the crystal particle sizes of ZnO in MOF-5 are in the range of 5-18 nm, which are larger than the pore size of MOF-5 (1.3 nm). This clearly demonstrates that those ZnO nanoparticles are located outside the pores of MOF-5.     

A hybrid of adjustable trust-region and nonmonotone algorithms for unconstrained optimization

This study devotes to incorporating a nonmonotone strategy with an automatically adjusted trust-region radius to propose a more efficient hybrid of trust-region approaches for unconstrained optimization. The primary objective of the paper is to introduce a more relaxed trust-region approach based on a novel extension in trust-region ratio and radius. The next aim is to employ stronger nonmonotone strategies, i.e. bigger trust-region ratios, far from the optimizer and weaker nonmonotone strategies, i.e. smaller trust-region ratios, close to the optimizer. The global convergence to first-order stationary points as well as the local superlinear and quadratic convergence rates are also proved under some reasonable conditions. Some preliminary numerical results and comparisons are also reported.     

A stabilized formulation for the advection–diffusion equation using the Generalized Finite Element Method

This paper presents a stable formulation for the advection–diffusion equation based on the Generalized (or eXtended) Finite Element Method, GFEM (or X‐FEM). Using enrichment functions that represent the exponential character of the exact solution, smooth numerical solutions are obtained for problems with steep gradients and high Péclet numbers in one‐ and two‐dimensions. In contrast with traditional stabilized methods that require the construction of stability parameters and stabilization terms, the present work avoids numerical instabilities by improving the classical Galerkin solution with enrichment functions (that need not be polynomials) using GFEM, which is an instance of the partition of unity framework. This work also presents a strategy for constructing enrichment functions for problems involving complex geometries by employing a global–local‐type approach. Representative numerical results are presented to illustrate the performance of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd.     

Hydrothermal Synthesis of Two 3D Lanthanide(Ⅲ) Organometallic Polymers in the 3,5-Pyridinedicarboxylate System with Different Coordination Architecture

Two coordination polymers of lanthanide complexes [(Dy)2(3,5-PDA)3(H2O)2]n 1 and [(Pr)2(3,5-PDA)3(H2O)3]n 2 (3,5-PDA = pyridine-3,5-dicarboxylate) have been synthesized under hydrothermal conditions. The prepared compounds were characterized by elemental analysis, IR and TG analyses and single-crystal X-ray structure determination. Complex 1 crystallizes in monoclinic, space group C2/c with a = 14.104(2), b = 11.1129(16), c = 15.086(2) , β =92.138(2)o, V = 2362.8(6) 3, Z = 4, C21H13Dy2N3O14, Mr = 856.34, Dc = 2.407 g·cm-3, F(000) = 1616, μ(MoKα) = 6.359 mm-1, the final R = 0.0422 and wR = 0.1016 for 2000 observed reflections with I 2σ(I). Complex 2 crystallizes in triclinic, space group P1 with a = 8.9441(13), b = 9.3959(14), c = 14.625(2), α = 98.065(2), β = 95.481(2), γ = 104.9130(10)o, V = 1164.7(3) 3, Z = 2, C21H15Pr2N3O15, Mr = 831.18, Dc = 2.370 g·cm-3, F(000) = 800, μ(MoKα) = 4.224 mm-1, the final R = 0.0355 and wR = 0.0731 for 4092 observed reflections with I 2σ(I). These polymers are constructed from the 3,5-PDA ligand but they exhibit different kinds of metal-organic framework structures. Complexes 1 and 2 are constructed from M-C-O zigzag corner-linked chains (M = Dy and Pr). In 1, the chains are composed of 8-coordinated DyIII centers, while the chains are made up of 8- and 9-coordinated PrIII centers in complex 2. These chains are cross-linked to each other by the pyridine rings of 3,5-PDA ligands, generating three-dimensional architectures. The magnetic behavior of compound 1 has been investigated, showing it exhibits antiferromagnetic interactions among the DyIII ions.a (Tianjin Key Laboratory of Structure and Performance for Functional Molecule, College of Chemistry and Life Science, Tianjin Normal University, Tianjin 300387, China) b (State Key Laboratory of Element-organic Chemistry, Nankai University, Tianjin 300071, China)     

Incremental unknowns in three-dimensional stationary problem

The main purpose of this work is to set up the explicit matrix framework appropriate to three-dimensional partial differential equations by means of the incremental unknowns method. Multilevel schemes of the incremental unknowns are presented in the three space dimensions, and through numerical experiments, we confirm that the incremental unknowns method is efficient and the hierarchical preconditioning based on the incremental unknowns can be applied in a more general form.      

Perovskites with the Framework‐Forming Xenon

The Group 18 elements (noble gases) were the last ones in the periodic system to have not been encountered in perovskite structures. We herein report the synthesis of a new group of double perovskites KM(XeNaO₆) (M=Ca, Sr, Ba) containing framework‐forming xenon. The structures of the new compounds, like other double perovskites, are built up of the alternating sequence of corner‐sharing (XeO₆) and (NaO₆) octahedra arranged in a three‐dimensional rocksalt order. The fact that xenon can be incorporated into the perovskite structure provides new insights into the problem of Xe depletion in the atmosphere. Since octahedrally coordinated Xe^VIII and Si^IV exhibit close values of ionic radii (0.48 and 0.40 Å, respectively), one could assume that Xe^VIII can be incorporated into hyperbaric frameworks such as MgSiO₃ perovskite. The ability of Xe to form stable inorganic frameworks can further extend the rich and still enigmatic chemistry of this noble gas.