Coating Carbon Nanotubes with Europium Oxide

Carbon nanotubes (CNTS) coating with europium oxide by a simple method is reported in this letter for the first time. The CNTS were refluxed in a solution of nitric acid containing europium nitrate, and the pH value was subsequently ajusted with ammonia solution. At last, the mixture was filtered and annealed. The TEM micrograph showed that the CNTS were covered with a uniform thin layer with thickness of about 15 nm. The XRD results revealed that the CNTS were coated with europium oxide.     

A multireference configuration interaction method based on the separated electron pair wave functions

A multireference configurational interaction method based on the separated electron pair (SEP) wave functions, SEP‐CI approach, has been developed as an approximation to the traditional CASSCF method. It differs from the CASSCF method in that active orbitals are obtained from the SEP wave function without further optimization in the subsequent CI calculations, and the active space is automatically constructed according to the occupation coefficients of SEP natural orbitals. These features make the present SEP‐CI method computationally much less demanding than the CASSCF method. The applicability of the SEP‐CI method is illustrated with sample calculations on the insertion reaction of BeH₂ and dissociation energies of LiH, BH, FH, H₂O, and N₂. © 2005 Wiley Periodicals, Inc. J Comput Chem 27: 39–47, 2006     

Cloud Point Extraction Preconcentration of Trace Cadmium as 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone Complex and Determination by Flame Atomic Absorption Spectrometry

A new method for the determination of trace cadmium in water samples by flame atomic absorption spectrometry (FAAS) after cloud point extraction (CPE) is proposed. The method is based on the complexation of Cd with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) in the presence of non-ionic micelles of Triton X-100. The effect of experimental conditions such as pH, concentration of chelating agent and surfactant, equilibration temperature and time on cloud point extraction was studied. Under the optimum conditions, the detection limits are 0.64 ng mL^±1 with relative standard deviations (RSDs) of 2.1% (n = 10). The proposed method was applied to the determination of trace cadmium in water samples with satisfactory results.     

Selective bonding of pyrazine to silicon(100)-2x1 surfaces: the role of nitrogen atoms

The covalent binding of pyrazine on Si(100) have been investigated using high-resolution electron energy loss spectroscopy (HREELS) and x-ray photoelectron spectroscopy. Experimental results clearly suggest that the attachment occurs exclusively through the bonding of the two para-nitrogen atoms with the surface without the involvement of the carbon atoms, as evidenced from the retention of the (sp2) C-H stretching mode in HREELS and a significant down shift of 1.6 eV in the binding energy of N 1s. The binding mechanism for pyrazine on Si(100) demonstrates that reaction channels for heteroatomic aromatic molecules are strongly dependent on the electronic properties of the constituent atoms.     

全硅MCM-41担载的加氢脱硫催化剂的TPR研究

用TRP技术研究了以全硅MCM-41(Si-MCM-41)和HNO3交换的全硅MCM-41(H-MCM-41)为载体制备的Ni-Mo、Co-Mo和Ni-W加氢脱硫(HDS)催化剂的还原性能，并以0．8(wt)％二苯并噻吩(DBT)的十氢萘溶液为模型化合物，在高压固定床反应器上考察了上述催化剂的加氢脱硫(HDS)反应性能。结果表明，Si-MCM-41经稀HNO3交换后，所担载的Ni-Mo和Ni-W催化剂还原性能、HDS活性和加氢活性有显著变化，但对Co-Mo催化剂影响不大。这说明在Ni-Mo／H-MCM-41和Ni-W／H-MCM-41中可能存在氢溢流现象，DBT的HDS活性与载体表面酸性和氢溢流有关。     

超离子导体CaF2中的Ca2+亚晶格和F-亚晶格

CaF_2在熔化以前为超离子导体相。一些实验和理论的研究表明,在超离子导体相中,Ca~(2+)仍维持原有的面心立方骨架,而F~-则在Ca~(2+)骨架中运动。早期的分子动力学模拟结果表明Ca~(2+)的均方根位移仅约0.3A,而F~-的扩散系数可达2.6×10~(-5)cm·s~(-1),已是熔盐扩散系数量级。近年来的中子散射实验表明在扩散离子和近邻离子间存在着某种动力学相关。为解释这些事实,新近Gillan的分子动力学模拟表明扩散离子伴随着F~-亚晶格变形,而Kaneko和Ueda的分子动力学模拟则表明扩散离子伴随着近邻离子在同一运动方向的相关运动。进一步的研究尚待进行。八十年代初,Nelson等人提出了描述晶体、非晶和液态中键取向的键球谐函数方法。     

蜜蜂外激素9－ODA和9－HDA的合成

６－溴－２－己酮在Ｌｉ２ｃｕＣｌ４催化下与γ－溴代巴豆酸甲酯进行格氏偶联，合成了蜂王物质９－羰基－（Ｅ）－２－癸烯酸（９－ＯＤＡ），将其还原得到另一蜂王物质９－羟基－（Ｅ）－２－癸烯酸（９－ＨＤＡ）。该法是合成９－ＯＤＡ和９－ＨＤＡ的新路线。     

Microfluidic synthesis of high-valence programmable atom-like nanoparticles for reliable sensing

Synthesis of programmable atom-like nanoparticles (PANs) with high valences and high yields remains a grand challenge. Here, a novel synthetic strategy of microfluidic galvanic displacement (μ-GD) coupled with microfluidic DNA nanoassembly is advanced for synthesis of single-stranded DNA encoder (SSE)-encoded PANs for reliable surface-enhanced Raman scattering (SERS) sensing. Notably, PANs with high valences (e.g., n-valence, n = 12) are synthesized with high yields (e.g., >80%) owing to the effective control of interfacial reactions sequentially occurring in the microfluidic system. On the basis of this, we present the first demonstration of a PAN-based automatic analytical platform, in which sensor construction, sample loading and on-line monitoring are carried out in the microfluidic system, thus guaranteeing reliable quantitative measurement. In the proof-of-concept demonstration, accurate determination of tetracycline (TET) in serum and milk samples with a high recovery close to 100% and a low relative standard deviation (RSD) less than 5.0% is achieved by using this integrated analytical platform.

A novel synthetic strategy is presented for microfluidic preparation of programmable atom-like nanoparticles with high valences and high yields.     

一类新的毛细管气相色谱固定液—侧链液晶冠醚聚硅氧烷的研究

合成了一种新的毛细管气相色谱用固定液——侧链含冠醚液晶的聚硅氧烷,这种固定液易于涂渍在弹性石英毛细管柱上,柱效高,热稳定性好,极性中等,它具有高分子液晶和高分子冠醚固定液的双重保留性能,适于分离多种异构体。