Studies on the Electrochemical Behavior of Bleomycin at a Co/GC Ion Implantation Modified Electrode and Its Application

In a 0. 10 mol/L HAc-NaAc buffer solution (pH = 4. 59), a sensitive reduction peak of bleomycin was observed by linear sweep voltammetry at a Co/GC ion implantation modified electrode. The peak potential was-0. 73 V(iw. SCE). The peak current was proportional to the concentration of bleomycin over the range of 5.0 × 10-8-1.0× 10-6 and 1.0× 10-6-1. 0 × 10-5 mol/L with a detection limit of 2.0 × 10-8 mol/L. The electrochemical behavior of the reduction peak of bleomycin at the Co/GC modified electrode was studied by linear sweep and cyclic voltammetry and applied to the determination of bleomycin in urine. This method is simple, rapid and reliable. The reduction process is quasi-reversible. The experiments of AES and XPS showed that Co was surely implanted into the surface of GCE and the depth distribution of Co was in good agreement with Gooses normal distribution; the implanted Co at GCE improved the electrocatalytic activity.     

聚合物-溶剂-超临界CO_2三元体系的相行为

研究了聚合物－超临界二氧化碳二元体系溶解性,并考查了添加共溶剂对溶解性的影响,结果表明,添加共溶剂会大大提高ＣＯ２的溶解度．此外,还研究了聚合物－溶剂－超临界二氧化碳三元体系在高压时的相行为,探讨了组分性质、含量等对温度 压力相图的影响．随着ＣＯ２含量的增加,压力－温度相图Ｌ－ＬＶ（单一液相向液气两相共存）边界线的斜率会出现突变点,发生由Ｌ－ＬＶ边界线向Ｌ－ＬＬ（单一液相向液液两相共存）边界线的过渡,而Ｌ－ＬＶ边界线对不同聚合物并不敏感．     

Al_(66)Mn_9Ti_(25) La金属间化合物的变形行为与机制

研究了微量稀土元素La对Al6 6 Mn9Ti2 5 金属间化合物显微组织、变形行为、裂纹生成的影响。在Al6 6 Mn9Ti2 5 金属间化合物中添加微量La ,保持L12 结构 ,晶格常数基本无变化 ,促进了晶粒枝晶化和第二相弥散化 ,起到一定的抑制微裂纹生成和扩展以及沿晶开裂的作用 ;同时 ,还可增强位错的可动性 ,使压缩塑性得到改善。探讨了La改善变形行为的机制。     

Side‐chain functionalized liquid‐crystalline polymers and blends. IX.* Phase behavior and structure of comb‐shaped liquid‐crystalline ionomers containing calcium ions

Liquid‐crystalline (LC) ionomers containing 2–15 mol % calcium ions were synthesized by the exchange reaction between the nematic LC copolymer, bearing oxycyanobiphenyl mesogenic groups, and the carboxyl groups of acrylic acid, with calcium acetate. The incorporation of 2–3 mol % Ca ions in the LC copolymer leads to some rise in the clearing point and glass‐transition temperature. A further increase in the concentration of metal ions (>5 mol %) is accompanied by induction of the smectic A phase where clearing point and glass‐transition temperatures keep constant values. Phase behavior of the LC ionomers may be understood on the basis of a structural model that considers the dual role of calcium ions in a polymer matrix. Metal ions act as points of noncovalent electrostatic binding of the polymer chains and are capable of forming larger ionic associates (multiplets). The comparison of the phase behavior of sodium and calcium containing LC ionomers shows that the formation of ionic links may lead to the growth of structure defects suppressing a positive influence of charged groups on the mesophase clearing temperature. The orientation behavior of the LC ionomers in the magnetic field was studied. It was shown that the incorporation of calcium ions (3 mol %) in the LC copolymer matrix leads to the growth of orientation order parameter S of the nematic phase. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3953–3959, 2001     

Polyurethanes containing sulfur. III. New thermoplastic HDI-based segmented polyurethanes with diphenylmethane unit in their structure

Three series of new thermoplastic, high molecular weight, segmented thiopolyurethanes were synthesized by a one-step melt polymerization from newly obtained thiodiols, including bis[4-(2-hydroxyethyl)thiomethylphenyl]methane, bis[4-(3-hydroxypropyl)thiomethylphenyl]methane, and bis[4-(6-hydroxyhexyl)thiomethylphenyl]methane (BHHM), as chain extenders; hexamethylene diisocyanate; and 20–80 mol % poly(oxytetramethylene) glycol (PTMG; number-average molecular weight = 1000) as the soft segment. Solution polymerization with the chain extender BHHM gave considerably lower molecular weight polymers. The structures of all the polyurethanes were determined with Fourier transform infrared and X-ray diffraction analysis. The thermal properties of the polyurethanes were examined with differential scanning calorimetry and thermogravimetric analysis. Shore A/D hardness and tensile properties were also determined. All the polyurethanes showed partially crystalline structures; those obtained with 40–80 mol % PTMG were elastomers. An increase in the PTMG content decreased hardness, modulus of elasticity, and tensile strength, whereas elongation at break increased. BHHM-based polyurethanes obtained in the melt showed the best tensile properties. The polyurethanes exhibited definite glass transitions (−70 to −59 °C) that were nearly independent of the hard-segment content up to about 50 wt % (40–80 mol % PTMG), indicating the existence of mainly microphase-separated soft and hard segments. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1733–1742, 2001     

介孔L材料CMK-3对甲基紫的吸附性能

合成了高度有序的具有二维六方(P6mm)结构的介孔碳材料CMK-3;利用X射线衍射分析了CMK-3的晶体结构,利用氮气吸脱附(BET)试验测定了孔体积;测定了CMK-3对水溶液中甲基紫的吸附行为,考察了不同pH、温度及浓度下水溶液中甲基紫的静态吸附行为,并分析了酸性、中性、碱性条件下吸附剂对甲基紫和罗丹明B混合溶液的竞...     

Peripheral Templation‐Modulated Interconversion between an A4L6 Tetrahedral Anion Cage and A2L3 Triple Helicate with Guest Capture/Release

An anion‐coordination‐based A₄L₆ (“A” denotes anion and “L” is ligand) tetrahedral cage was constructed by a C₂‐symmetric bis‐bis(urea) ligand and phosphate anion, which showed reversible interconversion with the A₂L₃ triple helicate as a response to the template, concentration, or solvent. Notably, an unusual “peripheral” templation was found to be critical to stabilize the tetrahedral structure. This peripheral effect was utilized to assemble an “empty” A₄L₆ cage that allows the multi‐stimuli‐controlled capture/release of biologically important species such as choline and acetylcholine.     

Oximato-bridged copper(II) compounds: syntheses,molecular structures,magnetic, thermal and spectroscopic properties

Reaction of the Schiff base, 1-(4-methylimidazol-5-yl) phenylhydrazonopropane-2-one oxime (LH), with copper(II) perchlorate hexahydrate and copper(II) nitrate trihydrate in a 1 : 1 M proportion in methanol affords [Cu₂L₂(H₂O)(ClO₄)](ClO₄) (1) and [Cu₂L₂(H₂O)₂](NO₃)₂] (2) in moderate yields. Both 1 and 2 have been characterized by elemental analysis, ESI-MS, FT-IR, UV–vis absorption spectroscopy, EPR, electric conductivity, and magnetic susceptibility measurements. The X-ray crystal structures of 1·CH₃COCH₃ and 2 have been determined. Both compounds are dinuclear copper(II) complexes, with each copper μ₂-bridged by two oxime ligands in a μ₂-η¹,η² fashion. Variable temperature magnetic studies on 1 and 2 show that both compounds are dominated by an antiferromagnetic coupling through the oxime bridges.     

Solvent crystallized syndiotactic polystyrene. Thermal and dynamic-mechanical behavior

The syndiotactic polystyrene can crystallize in different forms, depending on thermal and solvent treatments. The influence of the polymorphism on the dynamic-mechanical behavior has been analyzed. Thermogravimetric and calorimetric analysis were also carried out. The effects of phase transitions and solvent release on the relaxation phenomena were observed, and the correlations between structure and dynamic behavior allow to better understand some aspects of the polymorphism phenomena.     

SELECTIVE SEPARATION OF WATER-ETHANOL MIXTURES THROUGH COPOLYMERIC MEMBRANES: Ⅰ. ACRYLIC ACID AND ACRYLONITRILE COPOLYMER AND ITS IONIZED MEMBRANES

The copolymer of acrylic acid and acrylonitrile has been synthesized and pervaporation properties of the copolymeric membranes have been investigated. In order to elucidate the influence of membrane-permeate interaction on the pervaporation of water-ethanol mixtures and to prepare much improved membranes, the membranes have been treated with alkali metal, alkali earth metal and transition metal salt aqueous solutions. The treated membranes (ionized membranes) exhibited higher separation factors than the untreated membranes. The separation factors of various alkali metal cation membranes decreased in the following order : Li~+>Na~+>K~+, and the permeation rates showed an opposite tendency. The dependence of pervaporation behavior on the copolymer composition ,feed concentration and operating temperature have been studied with both ionized and non-ionized membranes. The apparent activation energies of water and ethanol permeation were calculated.