Cr/MCM-41催化剂上的乙烯聚合行为

以纯硅ＭＣＭ４１为载体，负载Ｐｈｉｌｉｐｓ烯烃聚合催化剂活性组分Ｃｒ．ＸＲＤ及ＴＥＭ表征结果表明，所得到的Ｃｒ／ＭＣＭ４１催化剂具有良好的晶体结构和较理想的长程有序一维孔道．ＦＴＩＲ和Ｒａｍａｎ光谱表征结果表明，Ｃｒ／ＭＣＭ４１上不仅可发生乙烯聚合过程，而且形成的聚乙烯以结晶和无定形两种形态存在．乙烯聚合活性不仅与反应参数有关，而且与Ｃｒ的负载量密切相关．用于乙烯聚合后，Ｃｒ／ＭＣＭ４１催化剂仍保持其特征的晶体结构和一维孔道结构．     

连续一级反应的热动力学研究

本文把时间比法引入热动力学研究,建立了连续一级反应的热动力学研究法,并用来研究了一个连续反应体系的热动力学,验证了该方法的正确性.     

单柱离子色谱法测定茶叶中草酸根和硫酸根的研究

本文研究单柱离子色谱分离测定茶叶中微量草酸根和硫酸根的方法。样品水浸泡，酸化液。上ＳｈｉｍＰａｒｓｋＩＣ－Ａ＿２柱分离，用２．０ｍｍｏｌ·Ｌ￣（－１）Ｈ－２Ｃ＿８Ｏ＿４／１．９ｍｍｏｌ·Ｌ￣（－１）Ｔｒｉ淋洗液洗脱，电导检测器检测，检测灵敏度为１．６Ｓ／ｃｍ，最低检出限０．０５μｇ／ｍＬ；线性范围Ｌ；相对标准偏差１．０６％；平均回收车９８．７２％９７．８８／。该法简便、快速、准确、灵敏、选择性好。     

catena‐Poly­[[tetra­aqua­iron(II)]‐μ‐succinato‐κ2O:O′]

The title complex, {[Fe(C₄H₄O₄)(H₂O)₄]}_n, is an infinite poly­meric compound bridged by the succinate dianion. Two carboxyl­ate groups coordinate in a monodentate manner to the Fe^II atom, in a trans fashion, with an O—Fe—O bond angle of 175.72 (6)° and Fe—O distances of 2.0886 (14) and 2.1008 (15) Å. One of the uncoordinated carboxyl­ate O atom forms an intramolecular hydrogen bond with a coordinated water mol­ecule. Extensive hydrogen bonding between parallel poly­meric complex chains results in a three‐dimensional supramolecular structure.     

Single electron emission from the closed-tips of single-walled carbon nanotubes

The single electron emission behaviors and characteristics from the well-defined quantized energy levels, corresponding to localized electronic states at the dome-structure tips, in single-walled carbon nanotubes (SWNTs) are investigated and illuminated by use of the energy level emission model in combination with the first-principles calculations on the electronic structures. Under the external electric field, the confined electrons are emitted simultaneously from each quantized energy level by virtue of the resonant tunneling effects. With increasing applied voltage, the emission current increases monotonically and exponentially up to the first peak value, and then steps into the increasing and decreasing "sawtoothlike" variations in sequence. The negative differential resistance or conductivity and the maximum current for SWNTs are simulated. The influences of localized electronic states and curvatures of the different closed tips on the single electron emission behaviors of SWNTs are evaluated and discussed. Also a few issues and applications relevant to electron emission of carbon nanotubes are addressed.     

去溶温度对微波诱导等离子体原子吸收光谱法分析性能影响的研究

本文研究了超声雾化微波诱导等离子体原子吸收光谱法(UN-MIP-AAS)中,去溶温度对选择载气流量、微波前向功率等因素的影响,并定量考察了去溶效果。通过改善去溶条件,提高了UN-MIP-AAS的分析性能。     

Crystal structure and strong antiferromagnetic interaction of a terephthalate-bridged binuclear copper(II) Complex, [{Cu(dipn)}2(μ-TPHA)](ClO4)2 (dipn = N-(3-aminopropyl)-1,3-propanediamine)

Three binuclear copper(II) complexes bridged by three different bridging ligands: μ-TPHA (terephthalato), μ-PHTA (phthalato) and μ-TCB (tetracarboxylatobenzene) have been synthesized. The crystal structure of [{Cu(dipn)}₂(μ-TPHA)](ClO₄)₂ where dipn = N-(3-aminopropyl)-1,3-propanediamine was solved at room temperature. The [{Cudipn}₂(μ-TPHA)](ClO₄)₂ complex consists of a μ-terephthalato bridging binuclear copper(II) cationic unit and two non-coordinated perchlorate anions. The TPHA ligand bridges in a bismonodentate fashion. The environment of the copper(II) ion is a distorted plane-square-planar coordination sphere. The magnetic properties of the three complexes have been investigated in the 75–300 K range, and show that the geometry of the Cu^II atom is the important factor for magnetic interactions in the terephthalato bridging binuclear copper(II) complexes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synthesis and crystal structure of an imidazolate-bridged dicopper tris(2-aminoethyl)amine complex

The [Cu(tren)(Im)Cu(tren)](ClO4)3·MeCN complex [tren=tris(2-aminoethyl)amine; Im=imidazolate anion] has been synthesized and characterized spectrally. The X-ray crystal structure analysis reveals that the imidazolate anion serves as a bridge to form a noncentrosymmetric dimeric structure in the complex. The co-ordination geometry about each copper(II) ion is a distorted trigonal bipyramid with three primary amine groups of the tren ligand forming the equatorial plane. The tertiary amine group and the imidazolate anion are in the axial positions. This revised version was published online in June 2006 with corrections to the Cover Date.     

Four New Nortriterpenoids from Phlomis umbrosa

Four new 28‐noroleanane‐derived spirocyclic triterpenoids, compounds 1 – 4 , were isolated from the rhizomes of Phlomis umbrosa. Their structures were elucidated on the basis of 1D‐ and 2D‐NMR analyses, in combination with high‐resolution MS experiments.