模板法制备α-MoO3纳米棒和纳米矩形片及光谱表征

以(NH4)6Mo7O24.4H2O为钼源,十六烷基三甲基溴化铵(CTAB)为模板剂,通过强酸性离子交换树脂(R-H)进行静态交换制备出前驱物,前驱物在600℃经不同时间焙烧,制备了α-MoO3纳米棒和纳米矩形小片。用FTIR,XRD,TEM和SEM等测试手段对样品的相态、结构和形貌进行了光谱表征,结果表明:前驱物经过600℃焙烧4和8h后,分别得到长度约1～1.6μm,直径约0.10～0.20μm,长径比为8的α-MoO3纳米棒和长度约0.14～0.18μm,宽度约60～80nm,厚度约28～32nm的纳米矩形小片。该法制备工艺简单,不用人为地调节pH、省去过多洗涤等过程,树脂可再生重复使用,副产品氯化铵可回收利用,无环境污染。     

Assembly of a new circle connecting circle chain through exerting the template role of a Keggin polyoxometalate

By using the flexible bis(triazole) ligand 1,2-bis(1,2,4-triazol-1-yl)ethane (bte), a polyoxometalate-templated compound, [Zn₂(bte)₄(SiW₁₂O₄₀)]·2H₂O (1), was synthesized under hydrothermal conditions. The compound was characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, photoluminescence spectroscopy, and cyclic voltammetry. Compound 1 is constructed from two motifs: the [SiW₁₂O₄₀]^4? polyanion and a bi-nuclear metal-organic circle [Zn₂(bte)₂]⁴⁺. The polyanion exerts a template role, inducing the formation of the bi-nuclear circle. The circles build a 1-D circle connecting circle chain through sharing the same Zn ions. Adjacent circles in the chain are vertical with each other. The template polyanion is surrounded by four circles from four different 1-D chains, forming a 3-D supramolecular structure.     

Two Keggin Templated Supramolecular Compounds by Exerting the Chelate and Linking Dual Roles of the Ligand 2, 2′‐Biimidazole

Two new Keggin templated supramolecular compounds, [Zn₂(H₂biim)₅(SiM₁₂O₄₀)] · 4H₂O [M = W ( 1 ), Mo ( 2 )] (H₂biim = 2, 2′‐biimidazole), were synthesized under hydrothermal conditions by using the ligand 2, 2′‐biimidazole. They were characterized by single‐crystal X‐ray diffraction, elemental analyses, IR and photoluminescence spectroscopy as well as cyclic voltammetry. The two isostructural compounds are constructed by two discrete supramolecular moieties: the inorganic chains consist of Keggin anions and metal‐organic chains constructed by [Zn₂(H₂biim)₅]⁴⁺ subunits. In the dinuclear [Zn₂(H₂biim)₅]⁴⁺ subunit, the H₂biim ligands exhibit a dual role, chelating and linking. The metal‐organic chains further construct a 3D supramolecular framework with channels, in which the Keggin‐based inorganic chains are accommodated. The electrochemical behaviors of compounds 1 and 2 bulk‐modified carbon paste electrodes ( 1 ‐CPE, 2 ‐CPE) were studied.     

基于图象差距分割的快速目标匹配识别算法

本文在模板匹配的算法基础上,引入图象差距度量的思想,以最大图象距离差选取好的阈值,实现目标与背景的有效分离,以减少模板匹配的计算区域为手段,减少算法的计算量,并提高模板匹配算法的识别精度.实验证明,该算法实现简单且行之有效.     

DNA模板诱导针状CdS纳米粒子的形成

利用生物分子作为模板合成无机纳米粒子 ,可以精确地控制生成粒子的结构、大小、形状等 ,这方面的工作已经引起了研究者的广泛关注[1].目前 ,已经对许多生物分子作为无机纳米粒子合成模板剂的可行性进行了探索 .Ｍａｎｎ等[2 ]利用蛋白质作为模板合成ＣｄＳ纳米粒子 ;Ｗａｎｇ等[3]利用哺乳类眼睛晶状体管蛋白作为模板合成纳米尺寸的ＣｄＳ粒子 ;Ｂｒａｕｎ等[4 ]将寡聚核苷酸连接在两个金电极之间 ,用ＤＮＡ分子作为模板生长出长 1 2 μｍ、直径 1 0 0ｎｍ的银纳米线 ;Ｓｈｅｎｔｏｎ等[5 ]用烟草斑纹病毒的蛋白外壳作模板剂诱导生成无机 …     

基于神经网络的模板匹配方法求正常星系红移

星系通常分为正常星系(NG)与活动星系(AG)两类。文章提出了一种自动获取NG红移的快速有效方法: (1) 由NG模板根据红移范围Ⅰ: 0.0～0.3与Ⅱ: 0.3～0.5模拟得到两类星系样本, 进行PCA变换获得样本特征向量; (2) 利用概率神经网络设计两类样本特征向量的Bayes分类器; (3) 对于实际NG光谱数据, 利用Bayes分类器进行分类确定其红移的范围, 然后在此范围内进行模板匹配得到红移的准确值。与在整个红移范围内的模板匹配方法相比, 此方法不但节省了50%的模板匹配运算量, 而且还大大提高了红移值测量的精度。文章研究结果对于大型光谱巡天所产生的海量数据的自动处理具有重要意义。     

在表面活性剂溶液中制备不同形貌的芘纳米材料

利用水溶液中表面活性剂分子和有机小分子间的相互作用,成功地制备了具有不同形貌的芘纳米颗粒和纳米棒.对其进行吸收光谱和荧光光谱等光物理行为的研究发现,不同形貌的纳米材料展现出不同的光学性质.同时对纳米材料的形成机制做了初步的分析和讨论.     

无电沉积高密度钯金属纳米线阵列

利用介孔氧化硅薄膜作为模板,通过无电沉积路线在介孔薄膜孔道内合成了高密度钯金属纳米线阵列.利用介孔薄膜导向剂的疏水区作为载体,引进钯金属疏水化合物并经热解和还原,得到钯微粒,以此为催化中心引发无电沉积,避免了传统无电沉积复杂的工艺过程.结果表明,纳米线尺寸均一,长径比大于60,完全填充了介孔薄膜的孔道,并可通过介孔模板孔径的选择对纳米线直径加以调控.     

硫和银共掺杂介孔TiO2的制备、表征及其对染料的光催化降解活性

以P123为模板,以钛酸四正丁酯、硝酸银和硫脲为原料采用模板法制备了一系列硫和银共掺杂介孔TiO₂光催化材料．利用SEM、XRD、BET和紫外-可见光谱等技术对其形貌、晶体结构及表面结构、光吸收特性等进行了表征．以甲基橙溶液的光催化降解为模型反应,考察了不同掺杂量的样品在紫外和可见光下的光催化性能．结果表明,用模板法制备的共掺杂介孔TiO₂光催化材料在紫外和可见光条件下较纯介孔TiO₂和单掺杂介孔TiO₂对甲基橙溶液具有更好的光催化降解效果, 且硫和银的掺杂量及样品焙烧温度显著影响该材料的催化性能．当硫掺杂量为2mol%和银掺杂量为1mol%,在500 oC 焙烧2 h所得光催化材料的催化性能最佳,4 h即可使甲基橙的降解率达98.8%,重复使用4次仍可使甲基橙的降解率保持在87.5%以上     

Confined on-surface organic synthesis: Strategies and mechanisms

On-surface synthesis has been one of the hottest research fields in surface science in the last decade, owing to its great potential for bottom-up synthesis of functional molecules and covalent nanomaterials. Compared to classical in-solution chemistry, all of the on-surface reactions are done without solvent, thus very minimal byproducts and no limitation of solubility are involved. However, because of its typically required ultra-high vacuum conditions, where only limited catalysts can be used, a key challenge for on-surface synthesis is the precise control of the reaction pathway. Countless efforts have been made for controllable synthesis of target chemical structures on surfaces by distinct strategies. These strategies can be summarized under following aspects: 1) rational choice of surfaces; 2) template effects based on two-dimensional (2D) environments; 3) on-surface thermodynamic and kinetic controls; 4) the participation of chemisorbed nonmetal adatoms on surfaces. This report reviews the recent progress toward the control of on-surface synthesis and raises a series of questions at the end, which deserve further explorations in the future.