阴离子型含氟两亲接枝共聚物的合成及其胶束化行为研究

以聚乙二醇甲醚甲基丙烯酸酯(MPEGMA)为大分子单体,甲基丙烯酸六氟丁酯(HFMA)、对苯乙烯磺酸钠(NaSS)为共聚单体,采用大分子单体接枝共聚法,制备了一种阴离子型含氟两亲接枝共聚物P( HFMA-co-NaSS) -g-PEG.利用FTIR、1H-NMR和19F-NMR对共聚物的分子结构进行了表征.表面张力法测...     

激光解吸电离质谱法分析富勒烯

论述了用激光解吸电离谱法分析富勒烯。因在电离过程中富勒分子不发生裂解，因此这种方法可直接用于富勒烯混合物的分析而勿需任何预分离。还给出了用本法分析较大、较稳定富勒烯分子的质谱图。     

A KIND OF FLUORESCENCE PROBE TO STUDY THE KINETICS OF POLYMERIZATION PROCESS

Fluorescence properties of 1-pheny1-3-(4'-nitrophenyl) pyrazoline (PNP) were studied inbulk polymerization process of methylmethacrylate (MMA). The fluorescence intensity of PNPwas enhanced and the emission maximum was blue shifted with the polymerization progress. Inthe period of auto-acceleration of the polymerization the enhancement of fluorescence intensityand blue shift of peak wavelength in spectra could be observed evidently. This means that thesolvatochromic properties of PNP are influenced not only by the solvent polarity but also by theviscosity of the medium (especially by the phase transitiott). In solid state PNP emits from thecharge transfer excited state without solvent relaxation. The transient emission spectra and theresults from Bakhshiev model of solvent relaxation coincide with that from the polymerizationexperiment.     

Hantzsch Ester as a Photosensitizer for the Visible‐Light‐Induced Debromination of Vicinal Dibromo Compounds

The debromination of vicinal dibromo compounds to generate alkenes usually requires harsh reaction conditions and the addition of catalysts. Just recently the visible‐light‐induced debromination of vicinal dibromo compounds emerged as a possible alternative to commonly used methods, but the substrate scope of this reaction is limited and a photocatalyst is necessary for the successful conversion of the starting compounds. A catalyst‐free visible‐light‐induced debromination of vicinal dibromo compounds with a base‐activated Hantzsch ester as photosensitizer is reported. The method has a wide substrate scope and a broad functional‐group compatibility.     

有机-无机杂多酸类离子液体催化汽油超声氧化脱硫

合成了一系列有机-无机杂多酸类离子液体, 并将其应用于超声作用下的催化模拟汽油氧化脱硫反应. 结果表明, 在超声波辅助下, 不仅反应时间大大缩短, 而且脱硫效率也大幅提高. 在合成的一系列催化剂中, Zr_0.25[BMIM]HPW₁₂O₄₀表现出最佳的催化活性. 考察了超声波功率、 超声/间隙时间、 催化剂用量、 H₂O₂用量、 反应温度及反应时间等因素对脱硫效果的影响. 以Zr_0.25[BMIM]HPW₁₂O₄₀为催化剂, 在优化的条件下[n(Cat.)=0.008 mmol, V(H₂O₂)=40 μL, V(模拟油)=10 mL, V(乙腈)=1 mL, 温度25 ℃, 时间10 min, 超声功率300 W, 超声时间2 s, 间隙时间1.5 s], 二苯并噻吩(DBT)的脱硫率达到97.8%; 该催化剂循环使用5次后, 脱硫率仍为81.9%; 其对不同硫化物的催化活性顺序为DBT>4,6-二甲基苯并噻吩(4,6-DMDBT)>乙硫醚>苯硫醚>正丁硫醇>甲基苯基硫醚>苯并噻吩(BT)>噻吩.     

实验室质量体系运行的关键控制点分析

通过对十几年来实验室计量认证的经验总结,对县级实验室质量体系运行情况进行了分析。指出了质量体系运行的关键控制点、存在的问题、解决问题的方法。经分析认为,基层实验室的生存和发展必然趋势是提高自身的检测能力。     

Direct observation of the intramolecular triplet-triplet energy transfer in poly(aryl ether) dendrimers

A series of benzophenone (BP) and naphthalene (NA) labeled poly(aryl ether) dendrimers (BP-Gn-NA), generations 1-4, were synthesized, and their photophysical properties were examined. Flash photolysis demonstrates that the triplet energy in BP-Gn-NA can be transferred from the peripheral BP chromophores to the core NA group with the efficiencies of ca. 0.97, 0.96, 0.88, and 0.54 and with the rate constants of 1.4x10(8), 1.2x10(8), 9.5x10(7), and 1.3x10(7) s-1 at room temperature for generations 1-4, respectively. The transient absorption spectra of BP-Gn-NA show clearly the formation of the triplet NA absorption along with the decay of the triplet BP one with an isosbestic point at 475 nm, which gives direct evidence of the triplet energy transfer from the periphery BP chromphores to the core NA group. The phosphorescence of the NA group attached to the focal point was observed when the periphery BP chromophores were selectively irradiated in BP-G1-NA at 77 K. The triplet energy transfer occurs at 77 K with the efficiencies of 1.0, 0.16, 0.17, and 0.21 for generations 1-4, respectively. The intramolecular triplet energy transfer is proposed to proceed mainly via a through space mechanism.     

液质联用中接口离子化新技术

液相色谱-质谱联用(简称液质联用,LC-MS)将色谱的高分离效能与质谱强大的结构测定功能结合,不仅实现了对复杂混合物更准确的定性定量分析,而且简化了样品的前处理过程,使样品分析更简便,在药物分析、食品与环境分析以及生物样品检测等众多领域得到了广泛的应用。作为LC-MS的核心组成部分,液质接口的作用是将LC的液体引入,发生电离,并将生成的离子传输进MS。因此,接口离子化技术的改进直接影响了LC-MS的发展和应用。为了获得更高的灵敏度和更广泛的适用性,研究人员一直致力于离子化技术的研究,以促进分析物的解吸,提高其电离和传输效率,减少基质效应的干扰。本文针对近年来LC-MS接口离子化技术的改进和发展,从离子化原理出发,对接口离子源的构造、影响电离的因素、以及相关的应用进行综述,探讨其优缺点,并对LC-MS接口离子化技术的发展趋势进行了展望。     

复合材料失效判据有效性验证方法研究

为系统地验证复合材料失效判据计算精度和有效性范围,给出了4种材料体系、6种铺层形式的层合板在单轴、双轴载荷下的失效试验数据,用以评估复合材料失效判据在单向层合板失效包线、多向层合板初始失效包线、多向层合板最终失效包线、层合板变形及层合板的破坏特性等五个方面的预测能力。并根据验证方法和有效性评估策略对失效判据计算精度进行量化考核,给出了失效判据在五个层面上的计算精度。