Zinc Ion Doped Solid-Phase Extraction of Eicosapentaenoic Acid and Docosahexaenoic Acid from Antarctic Krill

Antarctic krill crude extracts contain high levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Accordingly, the solid phase extraction of EPA and DHA from Antarctic krill crude extracts has attracted significant research interest. This study compared the extraction of EPA and DHA from Antarctic krill crude extracts using an aminopropyl, zinc ion-doped silica, and C₁₈ and zinc ion-doped C₁₈ solid-phase column. The best extraction effect was obtained using the zinc ion-doped C₁₈ SPE with water containing methanol as the eluant. The efficiency increased gradually with increasing methanol concentration from 12.5 to 25% in the washing stage, and when pure methanol (5.0 mL) or acetonitrile (3.0 mL) was used as the eluant. To detect EPA and DHA, the acids were first converted to their methyl esters and detected by gas chromatography with flame ionization detection (GC–FID). In the zinc ion-doped C₁₈ elution fractions, EPA and DHA were isolated from the crude extracts in high yield (85–91% (r² = 4.8–6.3%)).     

Watching Nanoparticles Form: An In Situ (Small‐/Wide‐Angle X‐ray Scattering/Total Scattering) Study of the Growth of Yttria‐Stabilised Zirconia in Supercritical Fluids

Understanding nanoparticle‐formation reactions requires multi‐technique in situ characterisation, since no single characterisation technique provides adequate information. Here, the first combined small‐angle X‐ray scattering (SAXS)/wide‐angle X‐ray scattering (WAXS)/total‐scattering study of nanoparticle formation is presented. We report on the formation and growth of yttria‐stabilised zirconia (YSZ) under the extreme conditions of supercritical methanol for particles with Y₂O₃ equivalent molar fractions of 0, 4, 8, 12 and 25 %. Simultaneous in situ SAXS and WAXS reveals a quick formation (seconds) of sub‐nanometre amorphous material forming larger agglomerates with subsequent slow crystallisation (minutes) into nanocrystallites. The amount of yttria dopant is shown to strongly affect the crystallite size and unit‐cell dimensions. At yttria‐doping levels larger than 8 %, which is known to be the stoichiometry with maximum ionic conductivity, the strain on the crystal lattice is significantly increased. Time‐resolved nanoparticle size distributions are calculated based on whole‐powder‐pattern modelling of the WAXS data, which reveals that concurrent with increasing average particle sizes, a broadening of the particle‐size distributions occur. In situ total scattering provides structural insight into the sub‐nanometre amorphous phase prior to crystallite growth, and the data reveal an atomic rearrangement from six‐coordinated zirconium atoms in the initial amorphous clusters to eight‐coordinated zirconia atoms in stable crystallites. Representative samples prepared ex situ and investigated by transmission electron microscopy confirm a transformation from an amorphous material to crystalline nanoparticles upon increased synthesis duration.     

氮掺杂石墨烯的制备及其超级电容性能

以氧化石墨烯(GO)为原料, 尿素为还原剂和氮掺杂剂, 采用水热法合成了氮掺杂石墨烯. 利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶变换红外(FTIR)光谱、X 射线衍射(XRD)、X 射线光电子能谱(XPS)、氮气吸脱附分析、电导率和电化学测试对样品的形貌、结构、组成以及电化学性质进行表征. 结果表明:水热条件下尿素能有效地化学还原GO并对其进行氮掺杂; 通过调节原料与掺杂剂的质量比, 可以得到不同氮掺杂含量的石墨烯, 氮元素含量范围为5.47%-7.56% (原子分数); 在6 mol·L^-1的KOH电解液中, 氮元素含量为7.50%的掺杂石墨烯的超级电容性能最优, 即在3 A·g^-1电流密度下首次恒流充放电比电容可达184.5 F·g^-1, 经1200次循环后的比电容为161.7 F·g^-1, 电容保持率为87.6%.     

Synthesis of Cobalt Doped Mesoporous Silica with high Cyclohexanone Selectivity for Catalytic Oxidation of Cyclohexane by the wild Sugarcane-grass Stems Bio-template Route

以野生滇蔗茅为生物模板剂合成Co掺杂的介孔SiO2催化氧化环己烷.并用X射线衍射、N2-物理吸附和解吸附、紫外-可见光光度计、傅里叶红外光谱仪和扫描电镜对材料进行了表征.X射线衍射、N2-物理吸附和解吸附研究结果表明该材料为介孔材料且氧化钴高分散于介孔材料的表面.紫外-可见光光谱表明钴离子以Co2＋和Co3＋的形态存在.环己烷的催化氧化结果表明催化剂能高效催化环己烷（环己烷的转化率为71.0%）转化为环己酮（选择性高达76.7%）.催化剂的重复性试验表明该催化剂具有较高的稳定性,循环使用3次后,催化活性仅有微小的改变.     

Nano-sulfated zirconia as an efficient, recyclable and environmentally benign catalyst for one-pot three component synthesis of amidoalkyl naphthols

One pot synthesis of amidoalkyl naphthols by reaction of aromatic aldehydes,2-naphthol and amide/urea using nano-sulfated zirconia as a catalyst is reported.The reaction was carried out under solvent-free conditions.The method gave good yields of amidoalkyl naphthols in short reaction time.The catalyst is recycled for five consecutive times without loss of activity.     

Solid‐State Electrochemiluminescence of F‐doped SnO2 Nanocrystals and Its Sensing Application

Electrochemiluminescence (ECL) behaviors and mechanisms of fluorine‐doped tin oxide (F‐SnO₂) semiconductor nanocrystals (NCs) were firstly investigated in both of nonaqueous and aqueous solutions via potential scanning or pulsing. Furthermore, the ECL of F‐SnO₂ was applied successfully to detect dopamine based on the quenching effect.     

Mesoporous Silica Sputter‐Coated onto ITO: Electrochemical Processes,Ion Permeability,and Gold Deposition Through NanoPores

“Simple” silica films of 50 nm and 100 nm thickness are sputter‐coated onto ITO substrates and shown to be structured with in‐planed features of ca. 15 nm and pores <5 nm (based on GISAXS). In electrochemical measurements membrane pore effects are observed. The oxidation current for Fe(CN)₆^4? in aqueous KNO₃ strongly depends on the electrolyte concentration. Poly‐cationic poly(diallyl‐dimethylammonium) (PDDA) cannot enter these pores, but is adsorbed onto the outer surface of the silica film. During gold electrodeposition, PDDA causes growth of “discs”. Gold deposits adhere well and a comparison of glucose electrooxidation activity reveals significant improvements.     

High efficiency event-counting thermal neutron imaging using a Gd-doped micro-channel plate

An event-counting thermal neutron imaging detector based on 3 mol % nattGd2O3-doped micro-channel plate （MCP） has been developed and tested. A thermal neutron imaging experiment was carried out with a low flux neutron beam. Detection efficiency of 33% was achieved with only one doped MCP. The spatial resolution of 72μ m RMS is currently limited by the readout anode. A detector with larger area and improved readout method is now being developed.     

Heterodoped nanoflakes: synthesis and characterization of sulfur‐doped NbSe2 nanoflakes

Doping of NbSe₂ with heteroatoms is an effective way to tailor its properties. Here, solid phase synthesis process has been utilized for growing uniform and excellent crystalline nano‐NbSe₂ by sulfur dopant during the growing process. The sulfur‐doped mechanism of nano‐NbS_2xSe_2(1‐x)(x = 0.03∼0.2) has been investigated: the sulfur atoms not only replace the Se position but also intercalate in layer gap by one‐step reaction. In the structure of NbSe₂, the sulfur atoms replace the positions of Se atoms and then are located in the empty octahedral positions of van der waals gap between the NbSe₂ layers with the increase of sulfur content. The lubrication properties of the as‐prepared NbSe₂ and sulfur‐doped NbSe₂ powders as additives in HVI1500 base oil were discussed. The lubrication properties of base oil was improved by both NbSe₂ and sulfur‐doped NbSe₂. Furthermore, the lubrication properties of sulfur‐doped (0.1at%) NbSe₂ are better than those of pure NbSe₂ in HVI1500 base oil, which could be attributed to their thin laminated structure and the sulfur dopant.     

以UV胶为纤芯本底的CdSe/ZnS量子点光纤光致荧光光谱的传光特性

制备了一种以紫外（UV）固化胶为纤芯本底的CdSe/ZnS量子点掺杂光纤.通过测量不同掺杂浓度和光纤长度下的量子点光致荧光光谱,得到了荧光峰值强度与量子点掺杂光纤浓度和长度的关系,确定了UV胶纤芯本底下的量子点的吸收系数、合适的掺杂浓度和光纤长度.结果表明|UV胶在光纤中具有吸收小、收缩率低、与石英光纤包层折射率匹配、性能稳定等特点,是一种比较理想的实验室制备量子点光纤纤芯本底的材料.