氮杂冠醚研究Ⅶ、双仲胺型氮杂冠醚对过渡金属离子的选择性萃取作用

合成了五种新型双仲胺型氦杂冠醚，研究了它们对过渡金属离子进行液—液萃取，并用原子吸收法测定其浓度。实验结果表明：这类冠醚对Ａｇ￣＋、Ｐｄ￣（２＋）、和Ｐｔ￣（４＋）等贵金属离子有较强的选择配位性能，对选择性分离这些金属离子有重要的意义。     

双马来酰亚胺增韧研究Ⅱ.链扩展双马来酰亚胺及其树脂的合成及表征

合成了一系列结构不同和链长短不一的双马来酰亚胺，并对其结构和性能作了表征，同时研究了它们的固化反应和固化产物的性能。用双马来酰亚胺和二烯丙基化合物反应制造了增韧树脂，研究了该树脂的固化和热稳定性。     

几种杂多阴离子柱撑水滑石的合成与吸附行为

柱撑水滑石类层柱状阴离子粘土是一类新型层柱材料，由于其二维孔道结构的可调变性及潜在的择形催化性能，已引起人们的重视[1-3]．迄今，人们已合成了包括无机和有机阴离子，同多和杂多阴离子（Polyoxometalates，简称POMs）以及配合物阴离子在内的多种柱撑水滑石，其中同多和     

肿瘤患者放疗前后血清八种微量元素含量的研究

对临床、病理、放射线或CT检查确诊的82名癌肿患者，在放疗前后和对42名健康人进行了微量元素铁、锌、铜、锰、硒，铬、钴、镍的分析。研究结果显示：1．癌肿患者血清铜、镍、锰、铬、钴的含量比健康人高，而血清锌、铁、硒的含量却比健康人低；2．血清Cu／Zn、Cr／Zn、Co／Zn、Ni／Zn的比值癌肿患者均比健康人高，而Fe、Zn、Se／Zn的比值却相反。因此，可根据血清铜升高、血清锌降低，血清铜／锌比值升高的特点。用于癌肿的早期诊断；3．癌肿患者放疔后血清铁、锌含量进一步下降，铜、锰、铬的含量也出现降低，唯有硒的含量有所上升。因此，放疗时应注意补充铁、锌、铜元素。     

New perylene polyimides containing p‐n diblocks for sensitization in TiO2 solar cells

Three novel perylene polyimides (PPIs) containing p‐n diblock units were designed and synthesized for use in dye‐sensitized mesoporous TiO₂ solar cells. They all dissolve in m‐cresol and N‐methyl‐2‐pyrrolidone (NMP). Their visible light absorption, electrochemical and photoelectrochemical properties were systematically studied. The polyimides have band gap energies of 2.16, 2.19 and 2.25 eV deduced from ultraviolet–visible absorption spectra, and electron affinity (E_a) and ionization potential (IP) of ?3.93 and 6.10 eV for PPI1, ?3.94 and 6.13 eV for PPI2, ?3.93 and 6.59 eV for PPI3, respectively, deduced from cyclic voltammogram. Experimental data show that introduction of 4,4′‐bisaminetriphenylamine cannot only greatly enhance optic‐electro conversion efficiency, but also enhance the dissolubility which in favorable for making the devices. The relationship of structure and properties of PPI is discussed and the mechanism of photocurrent generation is explained. Copyright © 2004 John Wiley & Sons, Ltd.     

Which electron count rules are needed for four-center three-dimensional aromaticity?

A series of charged and neutral four-center n-electron (4c-ne, n = 1-4) molecules based on the adamantane framework, but which include combinations of boron, nitrogen, and phosphorus atoms at bridgehead positions, were studied computationally at the B3LYP/6-31G* level of density functional theory (DFT). The three-dimensional aromaticity, observed earlier for the 1,3,5,7-bisdehydroadamantane dication (1), is found to be general for 4c-2e electron systems. The degree of electron delocalization, evaluated by energetic, geometric, and various magnetic criteria, is quite independent of the molecular symmetry (point groups vary from Td to Cs), the degeneracy of the orbitals, the molecular charges, and the nature of the atoms participating in the delocalized bonding. Although the multiple positive (e.g., in 1 and some of the heteroatom systems) and multiple negative charges are strongly repulsive, the rigid adamantane frameworks help hold the bridgehead atoms within bonding distances with the fewer available electrons. The corresponding 4c-1e doublets are approximately half as aromatic as the 4c-2e singlets based on the same criteria. However, the three-electron systems may either adopt distorted but still four-center delocalized structures, or alternative 3c-2e two-dimensional arrangements in which the fourth bridgehead atom is more distant. There is no need to derive special rules for each point group for 4c-ne systems. Although the three-dimensional stabilization is computed to be quite appreciable, ranging between 10 and 50 kcalmol(-1), this delocalization energy is generally not sufficient to overcome distortion due to strain in higher homologues of 1 and in analogous noncage systems. Among the various 4c-2e homoadamantanedehydro dications studied, only the 1,8-dehydrohomoadamandiyl-3,6-dication forms a three-dimensional aromatic system.     

Identification of ochratoxin A in food samples by chemical derivatization and gas chromatography-mass spectrometry.

The contamination of foods with ochratoxin A can be determined very sensitively by high-performance liquid chromatography (HPLC) with fluorescence detection. A novel procedure is described to confirm OA-positive results quantitatively down to the HPLC detection limit of 0.1 ppb. For this, ochratoxin A in the sample extract is converted into its O-methylochratoxin A methyl ester derivative, which is identified subsequently by gas chromatography-mass spectrometry negative-ion chemical ionization and multiple ion detection modes using the hexadeuterated O-methyl-d3-ochratoxin A methyl-d3 ester derivative as internal standard for quantification. In the analysis of more than 60 contaminated samples, the procedure was found to be very accurate.     

熔融织构生长强磁浮YBCO超导块材的取向和结构

采用熔融织构生长法结合顶部Ｓｍ１２３籽晶技术，成功地制备了直径为２０ｍｍ的ＹＢＣＯ超导块材。该块材具有极强的磁性能。用Ｘ射线θ／２θ扫描和Φ扫描分析其结构表明，样品在三维方向上具有很强的择优取向，其ｃ、ａ、ｂ轴方向分别与Ｓｍ１２３籽晶的ｃ、ａ、ｂ轴方向一致，并具有类似单晶的结构特点。