硅烷改性纳米ZrO2对镁锂合金表面环氧树脂涂层耐蚀性能的影响

采用涂覆法在镁锂合金表面制备了含双-[3-(三乙氧基硅)丙基]四硫化物(KH-69硅烷)改性纳米ZrO₂的环氧树脂涂层. 通过傅里叶变换红外光谱(FTIR)、 扫描电子显微镜(SEM)和电化学阻抗谱(EIS)等手段表征了该涂层. 考察了KH-69硅烷改性纳米ZrO₂浓度对环氧树脂涂层耐蚀性能的影响. 结果表明, KH-69硅烷改性纳米ZrO₂能显著提高镁锂合金表面环氧树脂涂层的耐腐蚀性能, 其中1.0%(质量分数) KH-69硅烷改性纳米ZrO₂环氧树脂涂层具有较好的耐蚀性能. 在NaCl溶液中浸渍528 h后的低频阻抗值为1.6×10⁹ Ω·cm², 相比在NaCl溶液中浸渍240 h的纯环氧树脂涂层提高约5个数量级.     

Cu2O/ZnO的形貌可控制备及光催化性能

以CuSO₄和ZnCl₂为原料, 采用温和的液相还原法制备得到Cu₂O/ZnO微米结构高效光催化剂. 研究了不同[Cu²⁺]/[Zn²⁺]比条件下所得Cu₂O/ZnO复合物的形貌和光催化活性. 通过5.5 h的光照, Cu₂O/ZnO光催化剂对甲基橙染料的降解率为(77.5±0.1)%. 将多形貌Cu₂O/ZnO复合物作为阳极, 铂片作为对电极, 中间注入甲基橙溶液, 组装“三明治”结构拟电池, 研究了复合物的光降解机制.     

冰晶石型氟化物(NH_4)_3FeF_6的水热合成及其磁学性质

首次采用水热法合成了冰晶石型氟化合物(NH_4)_3FeF_6,其结构和性质经X-射线粉末衍射、扫描电子显微镜和差热-热重分析表征。(NH_4)_3FeF_6属立方晶系,空间群Fm-3m,晶胞参数a=b=c=0.913 0 nm。对磁化率进行了表征。结果表明:随着温度降低,磁有序与晶体特征和孤立的磁单元有关。     

and Au6 clusters: Superatomic molecules bearing an SP3‐hybrid Au6 core

The octahedral Au₆ core is explored for the formation of novel SP³‐hybrid superatomic molecules by considering and Au₆ clusters (X= F, Cl, Br, I). The bonding between the four capping atoms and the Au₆ core requires a combination of 1S and 1P shells of the core leading to a set of four equivalent hybrid orbitals. Thus, combining the superatom concept with both the Lewis structure model and VSEPR theory contributes to the rationalization of structure and bonding in metal clusters. For example, our results consider the Au₆ clusters as analogues of the simplest perhalogenated hydrocarbon, CX₄.     

Syntheses,Structures, Electrochemistry,and Electrocatalysis of Three Copper(II) Coordination Polymers constructed from 5‐[4‐(1H‐Imidazol‐1‐yl)phenyl]‐1H‐tetrazole

Three coordination polymers (CPs) based on the 5‐[4‐(1H‐imidazol‐1‐yl)phenyl]‐1H‐tetrazole ( HL ) ligand, namely, [Cu(μ₂‐ L )(μ₄‐pbda)(H₂O)] ( 1 ), [Cu₂(μ‐Hbtc)(H₂btc)(μ₃‐OH)(μ₄‐ HL )] ( 2 ) and [Cu₅(μ₃‐ L )(μ₄‐ L )(μ₃‐ip)(μ₃‐OH)(H₂O)₂] · 2H₂O ( 3 ) (H₂pbda = 1,4‐benzenedicarboxylic acid, H₃btc = 1,3,5‐benzenetricarboxylic acid, H₂ip = isophthalic acid) were hydrothermally synthesized and structurally characterized. Complex 1 represents “weave”‐type 2D layers consisting of wave‐like 1D chains and 1D straight chains, which are further connected by hydrogen bonds to form a 3D supramolecular structure. Complex 2 exhibits a uninodal (4)‐connected 2D layer with a point symbol of {4⁴ · 6²}, in which the L ligand can be described as μ₅‐bridging and the H₂btc^– ions display multiple kinds of coordination modes to connect Cu^II ions into 1D “H”‐type Cu‐H₂btc chains. In complex 3 , 2D Cu‐ L layers with two kinds of grids and 1D “stair”‐type Cu‐ip chains link each other to construct a 3D {4¹² · 6³} framework, which contains the pentanuclear subunits. Deprotonated degree and coordination modes of carboxylate ligands may consequentially influence the coordination patterns of main ligands and the final structures of complexes 1 – 3 . Furthermore, electrochemical behaviors and electrocatalytic activities of the title complexes were analyzed at room temperature, suggesting practical applications in areas of electrocatalytic reduction toward nitrite and hydrogen dioxide in aqueous solutions, respectively.     

Geographic Characterization of Leccinum rugosiceps by Ultraviolet and Infrared Spectral Fusion

Leccinum rugosiceps is an edible mushroom belonging to genus Leccinum of Boletaceae. Its fruiting bodies are richer in nutrients than many vegetables and fruit. The model of support vector machine was established for the discrimination of L. rugosiceps from regions based on rapid and low-cost ultraviolet and infrared spectroscopies. The mid-level data fusion was performed by support vector machine. Compared to a single spectroscopic technique, mid-level data fusion provided higher accuracy by selecting the most significant variance from data matrixes based on partial least squares discriminant analysis. The accuracy of the classification of samples in the calibration and test sets were 85.00 and 94.74%, higher than separate measurements by ultraviolet or infrared spectroscopy. This approach has applications for authentication and quality assessment of L. rugosiceps.     

非原位拉曼光谱区分富锂层状氧化物的集成结构:一种预测Li2MnO3活化程度的有效方法

采用5种方法,即溶胶-凝胶法、高温固相法、共沉淀法、水热法和溶剂热法合成了富锂材料Li_(1.2)Mn_(0.6)Ni_(0.2)O_2。拉曼光谱研究发现共沉淀法制备的样品是固溶体结构,而其他4个样品是以不同尺度共生形成的复合物结构。电化学性能测试结果表明这5个富锂材料性能存在明显差异,尤其是在首次充电过程中5个样品位于4.5 V以上由Li_2MnO_3组分活化所贡献的容量明显不同,共沉淀法制备的具有固溶体结构的样品中由Li_2MnO_3组分活化贡献的容量最多。由此我们建立起电化学性能与两相集成方式的联系,不同的集成方式使得Li_2MnO_3组分活化所贡献的容量不同,进而影响了最终的电化学性能。     

超高效液相色谱-串联质谱法同时测定蔬菜水果中的40种农药残留

采用超高效液相色谱-串联质谱技术建立了蔬菜水果中40种农药残留的快速测定方法。蔬菜水果利用乙腈提取后直接进样分析,采用优化后的正离子多反应监测模式,外标法定量。40种农药含量在0.1~100μg/L范围内线性关系良好,检出限为0.10~5.0μg/kg,平均回收率为60.3%~134.8%,相对标准偏差为2.6%~17%。     

ETA对核电厂凝结水净化系统性能的影响

为抑制核电厂二回路汽水系统管路的流动加速腐蚀(FAC),AP1000核电机组推荐采用乙醇胺(ETA)作为二回路碱化剂。本文以我国在役核电厂凝结水净化系统的3种阳离子交换树脂作为研究对象,通过浸渍试验、运行周期试验及再生试验,分别考察ETA对凝结水净化系统离子交换树脂的性能、运行周期和再生特性等的影响,并与现用碱化剂——氨(NH3)进行了比较。试验结果表明,ETA作为二回路碱化剂与凝结水净化系统具有良好的相容性。     

Supramolecular Luminescent Lanthanide Dimers for Fluoride Sequestering and Sensing

Lanthanide complexes (Ln=Eu, Tb, and Yb) that are based on a C₂‐symmetric cyclen scaffold were prepared and characterized. The addition of fluoride anions to aqueous solutions of the complexes resulted in the formation of dinuclear supramolecular compounds in which the anion is confined into the cavity that is formed by the two complexes. The supramolecular assembly process was monitored by UV/Vis absorption, luminescence, and NMR spectroscopy and high‐resolution mass spectrometry. The X‐ray crystal structure of the europium dimer revealed that the architecture of the scaffold is stabilized by synergistic effects of the Eu? F? Eu bridging motive, π stacking interactions, and a four‐component hydrogen‐bonding network, which control the assembly of the two [EuL] entities around the fluoride ion. The strong association in water allowed for the luminescence sensing of fluoride down to a detection limit of 24 nM .