波纹状银纳米线的制备及其SERS性能研究

首先通过传统的多元醇方法合成了表面光滑的银纳米线,然后利用Fe（NO₃）₃作为刻蚀剂在室温条件下对合成的银纳米线进行刻蚀得到了具有波纹状表面的银纳米线. 通过扫描电镜（SEM）分析表明：银纳米线的表面粗糙程度随着刻蚀剂量的增加而增加,但过量的刻蚀剂又会导致纳米线的断裂甚至形成球状颗粒;当刻蚀剂的量为100 μL时,获得了波纹状表面的银纳米线. 对结晶紫（CV）的表面增强拉曼光谱（SERS）结果表明,这种波纹状银纳米线的拉曼信号强度比表面光滑的银纳米线提高了约5倍,其检测限可低至10^-10 mol/L. 此外,这种优势还可以延伸到敏感性检测10^-9 mol/L的对巯基吡啶（4-Mpy）分子,可以作为一种普适、有效的SERS活性基底.     

树莓状粒子的制备及应用研究进展

树莓状粒子是指具有较大比表面积、表面粗糙度和较高光散射特性的形似树莓的微粒。因其具有特殊的表面形态且表面易于设计,在颗粒自组装、超疏水和超亲水涂层制备方面有广泛的应用。树莓状结构粒子从物质组成上主要分为无机/有机、无机/无机和有机/有机复合粒子三种类型。迄今已有多种制备树莓状复合粒子的方法,但由于其组分的千变万化,还没有一种通用的方法。本文总结了近几年树莓状粒子的制备方法及其应用研究进展。     

镧掺杂对大洋锰结核制备铁氧体磁性的影响

大洋锰结核又称铁锰结核、多金属结核,常见于4 000～6 000 m的海底沉积物表层,在世界各大洋底均有分布,预计总储量超过3×1012 t[1].天然锰结核含有Mn和Fe,以及Cu、Co、Ni、铂族和稀土等60多种金属元素,其中锰占20%～30%,铁约占3～20%[2].从化学成分而言,大洋锰结核与Mn-铁氧体(铁酸锰)十分接近.以锰结核为原料合成Mn-铁氧体可以为这种天然资源的开发利用提供新思路.     

含氮竹节状碳纳米管的催化合成

以二乙胺为原料，用催化方法合成出了含氮大管径竹节状碳纳米管，以含铁 SAPO-5分子筛为催化剂，二乙胺经过1073K高温裂解得到的碳纳米管材料，其内径 约60nm,壁厚为6nm，并且成竹节状。它有较高的表面和较高的氮碳比。     

磁场诱导合成一维金属镍线的形貌控制

以镍盐与水合肼为起始原料,采用外加磁场辅助的水热法合成了表面具有纳米级刺状结构的一维金属镍线.向体系中引入十六烷基三甲基溴化铵(CTAB)作为包裹剂,可以合成表面光滑的金属镍线.对比大块镍,金属镍线的矫顽力得到了显著的增强.研究结果表明,外加磁场是线状结构形成的关键,而在镍核表面的CTAB吸附是控制表面形貌的重要因素.以甲基异丁基甲酮加氢制备甲基异丁基甲醇为探针反应,考察了所合成材料的加氢催化性能.结果表明,金属镍材料的一维结构与表面的纳米级刺状结构均有助于提高镍基催化剂的加氢催化活性.     

神木煤灰自身固硫的微观特性分析

当管式炉温由800 ℃升高到1 200 ℃时，神木煤灰的自身固硫率由63.5%降低到6.4%。晶相组成、孔隙结构和表面形态分析表明，800 ℃煤灰自身固硫渣样中CaSO4的质量分数高达18%，CaCO3和CaO的质量分数高达22.4%。渣样表面呈蓬松的棉絮状结构，颗粒内部有许多均匀密布的细小孔隙。1 200 ℃渣样中的CaSO4已全部分解，并且不存在任何CaCO3或CaO晶相，渣样表面由许多结构密实、表面光滑的块状颗粒组成，带有明显的烧结胀大和高温熔融的痕迹。1 200 ℃渣样的比表面积、孔容积和平均孔径等比800 ℃时急剧减小。     

固体表面及表面自由焓的测算

与液体一样,固体表面上的分子或原子受不均衡力场作用,具有较高的表面Gibbs自由焓。对于凝聚体系,因Gibbs自由焓与Helmholtz自由能近似相等,故习惯上也称为表面自由能(有时还不严格地称为表面能)。因液体可以流动,形成新表面时分子瞬间即达平衡位置,形成均匀、光滑的表面?..     

锰、铁的分离、聚集和锰结核的形成

本文就1983年夏季太平洋测区锰结核调查中所取得的12个站计29个沉积物(包括分层),16个站计35个锰结核以及水体等样品资料,通过Mn和Fe的分布与分配特点,结合东海陆架近岸区的有关资料探讨了这些金属共生、分离和聚集的规律以及其和锰结核形成的关系。     

钢液凝固过程中稀土夹杂物的显微形貌及形成机制的研究

用透射电镜和扫描电镜研究了钢液凝固过程中形成的稀土夹杂物的结构类型及类型及形貌，并运用热力学理论分析其形成过程。研究结果表明，在钢液凝固过程中，随着硫氧比的提高，稀土与氧硫反应产物依次是ＲＥ２０３、Ｒ３２Ｏ３与ＲＥ２９２Ｓ的复合物，ＲＥ２Ｏ２Ｓ以及ＲＥ２Ｓ３，此外还少量ＲＥＯ３。ＲＥ２ＯＥ呈典型胞状，ＲＥ２９Ｏ２Ｓ则为表面光滑的团球状。     

电化学沉积金纳米线结构及其电学特性

用电化学沉积方法，在有机介孔模板上制备出直径为90 nm的金纳米线.透射电子显微镜（TEM）分析结果表明，纳米线表面光滑并呈单晶结构.去除有机模板的金纳米线阵列用扫描电子显微镜（SEM）测试，纳米线顶端呈平台状，直径分布均一.我们利用原子力显微镜（AFM）测量了金纳米线阵列的微观结构，得到与SEM相一致的结果.在大气和室温条件下，用导电AFM针尖在接触模式下测量了单根纳米线的轴向I－V特性曲线，其结果为金属性.     

Multi-element analysis of manganese nodules by atomic absorption spectrometry without chemical separation

Five manganese nodules, including the USGS reference nodules A-1 and P-1, were analyzed for Co, Cu, Fe, K, Mg, Mn, Na, Ni and Zn without prior chemical separation by using a simultaneous multi-element atomic absorption spectrometer with an air—cetylene flame. The nodules were prepared in three digestion matrices. One of these solutions was measured using sixteen different combinations of burner height and air/acetylene ratios. Results for A-1 and P-1 are compared to recommended values and results for all nodules are compared to those obtained with an inductively coupled plasma. The elements Co, Cu, Fe, K, Mg, Mn, Na, Ni, and Zn are simultaneously determined with a composite recovery for all elements of 100 ± 7%, independent of the digestion matrices, heights in the flame, or flame stoichiometries examined. Individual recoveries for Co, K, and Ni are considerably poorer in two digests than this composite figure, however. The optimum individual recoveries of 100 ± 5% and imprecisions of 1–4%, except for zinc, are obtained when Co, K, Mn, Na and Ni are determined simultaneously in a concentrated digest, and in another analytical sequence, when Cu, Fe, Mg, Mn and Zn are measured simultaneously after dilution. Determination of manganese is equally accurate in the two sequences; its measurement in both assures internal consistency between the two measurement sequences. This approach improves analytical efficiency over that for conventional atomic absorption methods, while minimizing loss of accuracy or precision for individual elements.     

Effect of heat treatment on the physico-chemical properties and catalytic activity of manganese nodules leached residue towards decomposition of hydrogen peroxide

The effect of calcination temperature on the physico-chemical characterization of manganese nodule leached residue (MNLR) and water-washed manganese nodule leached residue (WMNLR) has been investigated on the basis of chemical analysis, XRD, TG-DTA, FTIR, surface hydroxyl groups, surface oxygen, reducing and oxidizing sites, surface area. XRD and IR confirm the presence of amorphous iron oxyhydroxides, delta-MnO2, which are converted to alpha-Fe2O3 and gamma-Mn2O3 phases above 400 degrees C of calcination, respectively. A solid solution of Fe2O3 and Mn2O3 is formed above 700 degrees C. The surface area, surface hydroxyl group, surface oxygen, reducing and oxidizing sites increase with the increase in calcination temperature up to 400 degrees C and then decrease with further rise in calcination temperature up to 700 degrees C. The catalytic activity of the sample towards H2O2 decomposition shows the similar trend as surface properties. A suitable Mn(3+)Mn4+ couple favours H2O2 decomposition reaction. The activity has been correlated with various physico-chemical properties.     

Determination of rhenium in manganese nodules by inductively coupled plasma mass spectrometry

Understanding of rhenium behavior in seawater gives an idea of the possible behavior of ⁹⁹Tc, which is an important radionuclide in long-term dose assessment for humans. In this study, Re determinations in manganese nodules, which have high Mn content, were carried out. Since Mn, Tc and Re are the member of group 7A in the periodic table, accumulation of Tc and Re in the nodules was also expected. After alkaline fusions and chemical separations, Re concentrations in manganese nodules were measured by ICP-MS. Total chemical recovery of the method for Re was 95% and the detection limit was 4.5 ng/kg. Re concentrations in the manganese nodules were very low, <4.5–49 ng/kg. The results indicated that the nodules had been mineralized under oxic conditions. This type of nodule could not be an important geochemical reservoir of Re and ⁹⁹Tc in the sea.     

Study on distribution of elements in deep-sea Pacific polymetallic nodules via two-dimensional mapping laser ionization orthogonal time-of-flight mass spectrometry

A newly developed two-dimensional mapping high irradiance laser ionization orthogonal time-of-flight mass spectrometer (LI-O-TOFMS) has been applied for the elemental mapping of polymetallic nodules. Two polymetallic nodule standards were used to demonstrate the efficacy of LI-O-TOFMS for the standardless semiquantitative analysis and the spatial distribution of elements in a deep-sea Pacific polymetallic nodule was mapped. It was found that the two groups of elements, Mn–Ni–Cu–Fe and Co–Si–Al, show clear element-dependent spatial relationships. It is hypothesized that these spatial distributions reflect the environmental and physico-chemical conditions during the nodule formation. LI-O-TOFMS is shown to be a powerful tool in elemental analysis of polymetallic nodules, with the detection limits down to 10^− 7 g/g and a dynamic range of 7 orders of magnitude. Based on the images acquired, the contents of elements and their relationships can be revealed visually.     

Determination of rare-earth elements,yttrium and scandium in manganese nodules by inductively-coupled argon-plastma emission spectrometry

A sequential-scanning, inductively-coupled argon plasma emission spectrometer is used for the determination of the rare-earth elements, plus yttrium and scandium, in manganese nodules. Wavelength selection is optimized to minimize spectral interferences from manganese nodule components. Samples are decomposed with mixed acids in a sealed polycarbonate vessel, and elements are quantified without further treatment. Results for U.S. Geological Survey manganese nodule standards A-1 and P-1 had average relative standard deviations of 6.8% and 8.1%, respectively, and results were in good agreement with those obtained by other methods.     

Characterization of Polish rape and honeydew honey according to their mineral contents using ICP-MS and F-AAS/AES

In this work twelve elements (Al, B, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni and Zn) were determined in 30 honey samples from various locations within Poland and in two different types of honey--rape and honeydew. Trace elements (Al, B, Cr, Mn and Ni) were determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), however, major elements (Ca, K, Mg, Na) and Cu, Fe, Zn were determined by Flame Atomic Absorption Spectrometry (F-AAS). Cluster analysis of honey data revealed that the origin of honey samples correlated with their chemical composition. It was shown that rape honey includes lower amounts of manganese than honeydew honeys. Also honeydew honey includes much higher concentrations of Al, Cu, K, Fe and Ni in comparison with rape honey. Moreover honeydew honey was found to have a higher mineral content, which reflects sources from which the honey is composed. Trace element analysis showed that the differences in the values found in honey samples could be used as evidence of the quality of honey samples.     

Multielemental analysis of ferromanganese nodules from Central Indian Ocean Basin by PIXE

Ferromanganese nodules found on the Ocean bed are complex heterogenous mixtures of several components. Two nodules from Central Indian Ocean Basin (CIOB) were analysed by proton induced X-ray emission (PIXE) technique using 3UD Tandem pelletron. The precision and the accuracy of this technique for chemical analyses has been confimed by analysing USGS Geological Standards. Thick sample targets were bombarded by 3 MeV protons for the multielemental analysis. GUPIX-96 software was used for spectral data analysis. Quantative estimate of K, Ca, Tl, V, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Mo, Ba, Ce, Tl and Pb has been ascertained. The occurrence of Ga, Ge, Rb and Zr in nodules from this region is reported for the first time. The role of manganese and iron oxide phases in determining the uptake of various trace elements from ocean water and bottom sediment pore water has been discussed.     

synthesis and properties of β-brominated metal complexes of meso-triphenylcorrole

Spectral properties and chemical stability of Mn(III), Mn(IV), Fe(III), Fe(IV), and Cu(III) complexes of β-octabromotriphenylcorrole [(β-Br)₈(ms-Ph)₃Cor], synthesized from β-unsubstituted compounds by their reaction with molecular bromine, were studied. Cyclic voltammetry, electron microscopy, and X-ray spectral microanalysis were used to obtain electrochemical characteristics of metal corroles M(β-Br)₈(ms-Ph)₃Cor and gain insight into the surface texture of active catalysts on the basis of metal corroles. The electron-acceptor β-bromine substitution in the MCor macrocycle shifts the equilibrium in electron-donor solvents to lower oxidation states of the metals and also stabilizes manganese and destabilizes copper complexes in the protondonor medium HOAc-H₂SO₄. The electrocatalytic activity of the complexes in the reduction of molecular oxygen depends on the nature of the ligand and increases in the order Mn ≤ Cu ? Fe in the case of β-octabrominated macrocycles. The character of distribution of active centers on the surface of the catalysts was established for the first time.     

非育珠背角无齿蚌软组织微量元素含量的分析

采用高频电感耦合等离子体发射光谱(ICP—AES)法测定了非育珠背角无齿蚌软组织中锰(Mn)、铁(Fe)、锌(Zn)、铬(Cr)、铝(Aj)、铜(Cu)六种微量元素及钙(Ca)、镁(Mg)的含量，分析了各种元素在不同软组织中的分布特征。结果表明：(1)在软组织中，各元素平均含量由高到低依次为：Ca，Mn，Mg，Fe，Zn，Al，Cr，Cu；(2)背角无齿蚌不同软组织中微量元素的含量不同，其中瓣鳃和外套膜中所测元素含量高于其他器官，特别是Mn，Fe的含量最高；Mn的含量甚至超过了宏量元素Mg；Al是闭壳肌中含量最丰富的微量元素。     

X射线荧光光谱法测定超硬铝合金中成分

叙述了用SRS 300型X射线荧光光谱仪测定超硬铝合金中铜、镁、锌、铁、硅、锰、铬、镍、钛、锆的X射线荧光光谱分析方法。试样用车床加工至表面平整、光滑,采用强度校正模型,由计算机拟合回归曲线。此法测定结果与常规湿法化学法测定结果相符。