厚度诱导的YBa2Cu3O7-δ超导薄膜剩余应力及临界电流变化

本文通过脉冲激光沉积法制备了不同厚度(80nm、320nm、1000nm和2000nm)的YBa2Cu3O7-δ(YBCO)超导薄膜,对它们的剩余应力和临界电流特性进行了对比研究.通过系列的激光显微Raman光谱和磁化曲线测量分别获得了薄膜剩余应力和磁化临界电流密度(Jc)对薄膜厚度的依赖关系.结果显示超导薄膜内剩余应力越小,Jc越高.对于中等厚度的薄膜样品(320nm和1000nm),其膜内剩余应力较小,同时由其特征的磁通匹配场大小推知在该厚度范围内的样品具有较高的线性缺陷密度,从而显示出较高的Jc值.     

Nonisothermal crystallization and morphology of poly(butylene succinate)/layered double hydroxide nanocomposites

Biodegradable poly(butylene succinate) (PBS) and layered double hydroxide (LDH) nanocomposites were prepared via melt blending in a twin-screw extruder. The morphology and dispersion of LDH nanoparticles within PBS matrix were characterized by transmission electron microscopy (TEM), which showed that LDH nanoparticles were found to be well distributed at the nanometer level. The nonisothermal crystallization behavior of nanocomposites was extensively studied using differential scanning calorimetry (DSC) technique at various cooling rates. The crystallization rate of PBS was accelerated by the addition of LDH due to its heterogeneous nucleation effect; however, the crystallization mechanism and crystal structure of PBS remained almost unchanged. In kinetics analysis of nonisothermal crystallization, the Ozawa approach failed to describe the crystallization behavior of PBS/LDH nanocomposites, whereas both the modified Avrami model and the Mo method well represented the crystallization behavior of nanocomposites. The effective activation energy was estimated as a function of the relative degree of crystallinity using the isoconversional analysis. The subsequent melting behavior of PBS and PBS/LDH nanocomposites was observed to be dependent on the cooling rate. The POM showed that the small and less perfect crystals were formed in nanocomposites.     

3-取代-12-氧代-N,N-双(2-氯乙基)脱氧胆酰胺的合成及其抑制癌细胞活性

以7-脱氧胆酸(1)为原料,由Jones试剂氧化得到3,12-二氧代-7-脱氧胆酸(2),然后与双(2-氯乙基)胺反应,得到3,12-二氧代-N,N-双(2-氯乙基)-7-脱氧胆酰胺(4),进一步通过对化合物4中的3-位羰基进行官能团转换,得到2个3-位分别被肟基、缩胺硫腙基取代的12-氧代-N,N-双(2-氯乙基)-7-脱氧胆酰胺类型化合物。同时,初步测试了合成物对肿瘤细胞增殖抑制活性,结果表明,化合物对宫颈癌细胞的生长有显著的抑制活性。     

基于适体竞争机理的溶菌酶电化学传感器

制备了基于溶菌酶适体竞争机理的信号减弱型电化学传感器,在玻碳电极上修饰羧基化的多壁碳纳米管,将带有氨基的互补适体DNA连接到多壁碳纳米管上。由于道诺霉素崁入电极上的互补DNA,而产生电化学信号,当有目标物时,适体与结合力更高的溶菌酶结合,原本的互补链解链,导致插入双链的道诺霉素脱落,电化学信号减弱。以微分脉冲伏安法测定溶菌酶,响应的范围为1～500 nmol/L,相关系数0.999,检测下限为0.5 nmol/L(S/N=3)。     

硫代多联吡啶铂(Ⅱ)配合物的合成、性质及在光催化制氢中的应用

合成了2个新配体4-(4-硫代乙酸)甲苯基-6-苯基-2,2’-联吡啶HC^N^N(PhCH2SCOCH3)(L3)和6-(4-硫代乙酸)甲苯基-2,2’-联吡啶HC^N^N(CH2SCOCH3)(L5)及其发光的铂(Ⅱ)配合物ClPtC^N^N(PhCH2SCOCH3)(C3)和ClPtC^N^N(CH2SCOCH3)(C5).通过1H NMR谱和质谱对它们的结构进行了表征,采用X射线单晶衍射分析确定了C3的晶体结构.利用紫外-可见吸收光谱、发射光谱及激发态寿命测定研究了它们的光物理性质和电化学性质,以及配合物作为光敏剂在光催化制氢中的应用.通过系列配合物产氢效率的比较,揭示了它们的产氢效率和激发态寿命的关系.     

顺式六氢-1H-呋喃并[3,4-C]吡咯的合成

以N-（甲氧甲基）-N-（三甲基硅甲基）苄胺和马来酸二甲酯为原料通过环加成、氢化铝锂还原、T_SOH催化脱水、氢氧化钯/碳催化氢化脱苄基四步反应,设计并合成了一种含氮、氧的杂环化合物--顺式六氢-1H-呋喃并[3,4-C]吡咯,其结构经¹H NMR, ¹³ C NMR和MS（ESI）表征。      

Highly Efficient Oxygen Reduction Reaction Fe-N-C Cathode in Long-durable Direct Glycol Fuel Cells

The oxygen reduction reaction in direct glycol fuel cells heavily relies on noble metal-based electrocatalysts. In this work, novel Pt group metal-free catalysts based on porous Fe-N-C materials are successfully synthesized as catalysts with high activity and durability for the cathode oxygen reduction reaction (ORR). Through the encapsulation of NH₄SCN salt, the surface elements and pore structure of the catalyst are effectively changed, and the active sites of Fe effectively are increased. The half-wave potential of the best Fe-N-C catalyst was –0.02 V vs. Hg/HgO in an alkaline environment. The porous Fe-N-C catalyst possesses a large specific surface area(1158 m²/g) and shows good activity and tolerance to glycol. The direct glycol fuel cell with the Fe-N-C cathode achieved a maximum power density of 62.2 mW/cm² with 4 mol/L KOH and 4 mol/L glycol solution at 25 °C and maintained discharge for more than 250 h at a 50 A/cm² current density.     

纳米金刚石掺混纳米氧化锌的场发射特性

利用水热法制备了菊花状的氧化锌纳米棒,并进行表征,将纳米氧化锌掺入纳米金刚石中配制成电泳液,超声分散后电泳沉积到钛衬底上,再经热处理后进行场发射特性的测试.结果表明:未掺混的金刚石阴极样品的开启电场为7.3V/μm,在20V/μm的电场下,场发射电流密度为81μA/cm2;掺混后阴极样品的场发射开启电场降低到4.7~6.0V/μm,在20V/μm电场下,场发射电流密度提高到140~158μA/cm2.原因是纳米ZnO掺入后,增强了涂层的电子输运能力、增加了有效发射体数目,提高了场增强因子β,而金刚石保证了热处理后涂层与衬底的良好键合,形成了欧姆接触,降低了场发射电流的热效应.场发射电流的稳定性随掺混ZnO量的增加而下降,要兼顾场发射电流密度及其稳定性,适量掺入ZnO可有效提高纳米金刚石的场发射性能.     

邻二氮杂菲分光光度法测定高铁酸钡

基于邻二氮杂菲分光光度法建立了Ba Fe O4的定量分析方法,并探讨了Ba Fe O4测定的适宜条件。经预处理的Ba Fe O4被硝酸酸化、盐酸羟胺还原后在HAc-Na Ac缓冲溶液中与邻二氮杂菲快速显色,生成橙红色络离子[(C12H8N2)3Fe]2+,该体系在510 nm波长处有最大吸收峰。利用分光光度计测定该体系510 nm处吸光度即可换算Ba Fe O4纯度。方法可应用于定量检测其他难溶性高铁酸盐。     

有机锡4-(4-吡啶基甲基硫代)苯甲酸酯的合成、结构与生物活性研究(英文)

通过4-(4-吡啶基甲基硫代)苯甲酸与三苯基氧化锡以及三环己基氢氧化锡反应,合成了三苯基锡4-(4-吡啶基甲基硫代)苯甲酸酯(1)及三环己基锡4-(4-吡啶基甲基硫代)苯甲酸酯(2)。它们的结构通过红外,核磁以及X-射线单晶衍射分析得到确证。化合物1表现为一维链状结构,而化合物2通过分子间的O-H…O和O-H…N氢键形成二维网状结构。生物活性测试表明,这2个化合物具有较高的抗肿瘤活性。