One-dimensional ferromagnetic array compound [Co3(SBA)2(OH)2(H2O)2]n, (SBA = 4-sulfobenzoate)

We report on the syntheses, crystal structure, and magnetic properties of the transition metal coordination polymer [Co₃(SBA)₂(OH)₂(H₂O)₂]_n, (SBA = 4-sulfobenzoate) in which CoO₆ octahedra are linked through their edges, forming one-dimensional (1D) Co(II) arrays running along the crystal a-axis. These arrays are further perpendicularly bridged by SBA ligand to construct a three-dimensional framework. Its magnetic properties have been investigated, and ferromagnetic interactions within the arrays have been found. From heat capacity measurements, we have found that this compound exhibits a three-dimensional ferromagnetic phase transition at T_C = 1.54 K, and the specific heat just above T_C shows a Schottky anomaly which originates from an energy gap caused by uniaxial magnetic anisotropy. These results suggest that [Co₃(SBA)₂(OH)₂(H₂O)₂]_n consists of weakly coupled 1D ferromagnetic Ising arrays.     

Highly electroactive nanosized α-LiFeO2

We obtained pure nanosized α-LiFeO₂ by a simple and quick method involving the reaction between goethite, lithium hydroxide and lithium nitrate at temperatures as low as 523 K. Unlike the known limited electrochemical activity of this polymorph, cells based on our nanosized electrode provided a remarkable high capacity in the first cycles and showed a good cycling life, due to its nanosized character and adequate morphology to enhance lithium insertion/deinsertion. Capacity values when cycling in the 1.5–4.5 V range are up to 150 mAh g⁻¹ in the 50th cycle. To our knowledge, the capacity values and its retention upon cycling are the best reported for this polymorph in an un-doped state.     

Determination of morpholinium ionic liquid cations in environmental water samples: development of solid-phase extraction method and ion chromatography

An ion chromatography and solid-phase extraction method has been applied for the separation and detection of morpholinium cations in environmental water samples. The water samples were purified and enriched by a UF-SCX sulfonic acid extraction column and eluted with 0.5 mol L⁻¹ phosphoric acid/sodium dihydrogen phosphate buffer solution/55% methanol. The target compounds were separated on a carboxylic acid cation exchange column with 5.0 mmol L⁻¹ methane sulfonic acid/2% acetonitrile as the mobile phase and direct conductivity detection. The method has been successfully applied to extract morpholinium cations from spiked water samples of Songhua River, Hulan River, East Lake, and Mopanshan Reservoir in China with the recoveries ranging from 75.0% to 98.3%. The relative standard deviations of intraday precision and interday precision are 2.1% and 5.9% or less, respectively. Using this method it is possible to preconcentrate water samples to 0.01–0.04 mg L⁻¹. The results show that the method is applicable to detection of morpholinium ionic liquid cations in environmental water samples and provides a new approach for monitoring ionic liquids in environmental water.

The analysis procedure of morpholinium ionic liquids in environmental water samples.

     

Single-atom rhodium anchored on S-doped black phosphorene as a promising bifunctional electrocatalyst for overall water splitting

Superior bifunctional electrocatalysts with ultra-high stability and excellent efficiency are crucial to boost the oxygen evolution reaction (OER) and the hydrogen evolution reduction (HER) in the overall water splitting (OWS) for the sustainable production of clean fuels. Herein, comprehensive density functional theory (DFT) computations were performed to explore the potential of several single transition metal (TM) atoms anchored on various S-doped black phosphorenes (TM/S_nx-BP) for bifunctional OWS electrocatalysis. The results revealed that these candidates display good stability, excellent electrical conductivity, and diverse spin moments. Furthermore, the Rh/S₁₂-BP catalyst was identified as an eligible bifunctional catalyst for OWS process due to the low overpotentials for OER (0.43 V) and HER (0.02 V), in which Rh and its adjacent P atoms were identified as the active sites. Based on the computed Gibbs free energies of OH*, O*, OOH* and H*, the corresponding volcano plots for OER and HER were established. Interestingly, the spin moments and the charge distribution of the active sites determine the catalytic trends of OER and HER. Our findings not only propose a promising bifunctional catalyst for OWS, but also widen the potential application of BP in electrocatalysis.     

A Ag-La heterometallic 2D layer based on mono-lacunary Keggin polyoxometalate: Synthesis,structure, and photocatalytic property

A new two-dimensional (2D) purely inorganic 4d-4f heterometallic compound [La(H₂O)₈][Ag{La(H₂O)₆}₂{SiW₁₁La(H₂O)₄O₃₉}₂]·13H₂O (1), based on mono-lacunary Keggin-type {α-SiW₁₁O₃₉} cluster (abbreviated to SiW₁₁), was conventional synthesized and characterized by elemental analysis, IR, TG, and single crystal X-ray diffraction. In compound 1, two mono-substituted {SiW₁₁La(H₂O)₄O₃₉}₂ clusters (abbreviated to SiW₁₁La) polymerize together to form a dimer. And the dimers are linked by Ag⁺ and La³⁺ heterometallic cations displaying a 2D network. Furthermore, the photocatalytic experiment indicates that the title compound presents excellent photocatalytic activity towards degradation of rhodamine B (RhB) dye.     

二元液体中动力学不均匀性与脆性的关系(英文)

过冷液体和玻璃有着复杂的结构和动力学性质.目前我们对他的研究是很不够的.当液体的温度远低于它的熔点时,它呈现非指数的驰豫行为.大量的实验和分子动力学模拟的研究表明这种非指数的驰豫行为是由动力学不均匀性引起的.计算机模拟已经提供了一些过冷液体的动力学不均匀性的相关信息.而Agell认为,液体可以粘度随温度的变化分为强,弱液体两种.脆性表示的是随着玻璃态的接近液体性质(如黏度)的改变速度.在这篇文章中我们通过模拟了三种不同二元Lennard-Jones液体,计算了它们的非高斯参数,脆性系数等一些参数,研究动了力学不均匀性和脆性的关系.得出了系统的脆性系数越小他的结构就越稳定,动力学不均匀性就越强的结论.     

五加生化胶囊的高效液相色谱指纹图谱研究

应用高效液相色谱(HPLC)法建立五加生化胶囊的指纹图谱。采用ANGLAVenusil XBP-C18色谱柱(250×4.6mm,5μm),以甲醇-0.1%磷酸溶液为流动相,梯度洗脱,检测波长为327nm,五加生化胶囊多数峰达到基线分离。采用2004A中药色谱指纹图谱相似度评价系统对11批样品的指纹图谱进行峰匹配,确定12个共有峰,11批五加生化胶囊指纹图谱的相似度均在0.90以上。结果表明:五加生化胶囊的HPLC指纹图谱特征性和专属性强,可较系统地用于五加生化胶囊的质量控制。     

二阶带时标的非线性奇异动力方程的m点边值问题的正解

研究二阶带时标的非线性奇异动力方程m点边值问题的正解,利用锥上的混合单调不动点定理,得到了正解的存在性和唯一性.本文中方程的非线性项可能是奇异的.并举例说明相应的结果.     

Multiple solutions for a class of semilinear elliptic problems with Robin boundary condition

In this paper, we show the existence of at least four nontrivial solutions for a class of semilinear elliptic problems with Robin boundary condition and jumping nonlinearities. Solvability of oscillating equations with Robin boundary condition is also investigated. We prove the conclusions by using sub-super-solution method, Fu?ík spectrum theory, mountain pass theorem in order intervals and Morse theory.     

一步水热法在Al掺杂ZnO纳米盘上可控自组装合成ZnO纳米棒阵列

通过简单的水热合成路线,在没有模板、表面活性剂的作用和未处理的基底上合成出铝掺杂ZnO 纳米盘,并以纳米盘为基底自组装合成了ZnO纳米棒阵列.扫描电镜(SEM)观察到铝掺杂ZnO纳米盘的厚度为 200 nm,纳米盘的尺寸约为2 μm;纳米棒的直径约为150 nm,长约1.5 μm.通过不同生长阶段的形貌变化探讨了ZnO纳米结构的形成机理,表明自组装过程存在两个成核阶段.另外, 研究了铝离子掺杂对样品光致发光性质的影响.