锂离子电池负极材料Li4Ti5O12的半固相法制备及碳包覆改性

由半固相法制得锂离子电池负极材料Li4Ti5O12,并研究了Li4Ti5O12的碳包覆改性.采用XRD、SEM、TEM以及HRTEM观察和分析产物的相结构与形貌.采用恒流充放电、循环伏安法和交流阻抗技术测试了材料的电化学性质.结果表明,Li4Ti5O12因颗粒团聚电化学性能严重下降,该电极在0.1C和0.5C首周期放电容量分别为121.7和87.6 mAh·g-1;碳包覆Li4Ti5O12/C材料呈球形分布,能抑制颗粒团聚,该电极倍率<0.5C时的放电比容量大于180 mAh·g-1,超过Li4Ti5O12的理论放电比容量(175 mAh·g-1);在1C、5C和10C倍率下,其容量仍保持在136、79.9和58.3 mAh·g-1,碳包覆改性材料具有优异的循环寿命和高倍率性能.     

黑莓汁及其发酵制品中鞣花酸的高效液相色谱测定

建立了高效液相色谱(HPLC)法测定黑莓汁及其发酵制品中鞣花酸含量的方法。采用Waters symmetry C18色谱柱(250×4.6 mm,5μm),流动相为体积比44∶2∶54的甲醇-乙酸乙酯-KH2PO4/H3PO4(5%)溶液(磷酸调pH为2.7),流速0.6 mL/min,检测波长:0～6 min 400 nm,6～7.5 min 350 nm,7.5～30 min 254 nm。该方法检测黑莓汁中鞣花酸含量,平均回收率为99.08%,相对标准偏差(RSD)为0.077%。同时采用此方法跟踪检测了黑莓发酵液中鞣花酸的含量。结果表明,黑莓汁样品无需经过复杂的前处理,即可达到良好的分离。方法操作简单,准确度高,无杂质干扰,可用于黑莓原汁及黑莓汁发酵制品中鞣花酸含量的测定。     

小型高分辨电子轰击离子源反射式飞行时间质谱仪的研制

常用的气体分析质谱仪使用四极杆质谱作为分析器,分辨率一般低于300,无法解决同质量数离子带来的干扰问题.本实验自行研制了一种小型高分辨气体分析质谱仪,它采用电子轰击离子源反射式飞行时间质量分析器.仪器腔体总长45 cm,在m/z 28的位置,质量分辨率达到3000(Full width at half maximum,FWHM),实现了CO和N2的半峰谷分离;在m/z 69的位置,仪器分辨率达到5000(FWHM).在直接大气压进样条件下,可以检测到空气中136Xe(含量7.8 μ g/m3)和80Kr(含量2.8 μg/m3).使用ADC采集时,仪器的动态范围为1 06.该仪器将作为高端气体质谱仪,应用于过程监测在线分析、环境有机挥发物研究、热分析质谱及催化反应监测等领域.     

Crystal structures and thermal decomposition kinetics of lanthanide complexes with 3,4,5-trimethoxybenzoic acid and 1,10-phenanthroline

A series of lanthanide complexes with the 3,4,5-trimethoxybenzoic acid(3,4,5-tmoba) and 1,10-phenanthroline(phen),[Ln(3,4,5-tmoba) 3 phen] 2(Ln = Pr(1),Nd(2) and Ho(3)),have been synthesized and characterized by a series of techniques including elemental analysis,IR spectra,X-ray crystallography and TG/DSC-FTIR technology.The three complexes have two kinds of coordination modes,in which the Pr 3+ and Nd 3+ cations are nine-coordinated and the Ho 3+ cation is eight-coordinated.The three-dimensional IR accumulation spectra of gaseous products for complexes 1-3 were analyzed and the gaseous products were identified by the typical IR spectra obtained from the 3D surface graphs.Meanwhile,we obtained the activation energy E of the first steps of complexes 1-3 by the integral isoconversional non-linear(NL-INT) method and discussed the non-isothermal kinetics of complexes 1-3 using the Malek method.Finally,SB(m,n) was defined as the kinetic method of the first-step thermal decomposition.The thermodynamic parameters △G≠,△H≠ and △S≠ of activation at the peak temperature were also calculated.     

硅胶基质高效液相色谱填料研究进展

高效液相色谱(HPLC)不仅是一种有效的分析分离手段,也是一种重要的高效制备分离技术。色谱柱是HPLC系统的核心,不同性能的填料是HPLC广泛应用的基础。硅胶是开发最早、研究最为深入、应用最为广泛的HPLC固定相基质,其制备方法主要有喷雾干燥法、溶胶-凝胶法、聚合诱导胶体凝聚法及模板法等。近年来,亚2μm小粒径硅胶、核-壳型硅胶、双孔径硅胶、介孔性硅胶、有机杂化硅胶等新型硅胶应用于HPLC并取得了色谱分离技术的飞速发展,例如基于亚2μm填料的超高压液相色谱技术、基于核-壳型填料的快速分离技术、基于杂化硅胶填料的高温液相色谱技术等。硅胶经表面化学键合、聚合物包覆等有机改性可制得先进的大分子限进填料、温敏性填料、手性填料等,大大扩展了HPLC的应用范围。本文对液相色谱用硅胶的制备方法、改性与修饰方法以及硅胶基质固定相的评价方法加以系统综述,概述了新型硅胶在HPLC中的应用进展,并对硅胶基质填料的发展方向与应用前景进行了展望。     

LaGaO3基固体氧化物燃料电池阳极材料Ce1-xTmxO2-δ（Tm=Cu,Mn,Fe）研究

以研究与Sr,Mg掺杂LaGaO3(LSGM)电解质匹配的阳极材料为出发点,系统研究了Ce1-xTmxO2-δ(Tm=Cu,Mn,Fe)固溶体的晶体结构、热化学稳定性、电化学性能和单电池发电实验。柠檬酸法合成的Ce1-xTmxO2-δ化合物在x<0.2时均为单相材料,与LSGM电解质有良好的热化学相容性。采用交流阻抗法研究了阳极材料的电化学性能,金属元素掺杂可以显著地改善CeO2电化学性能,Fe元素掺杂阳极材料极化电阻最小,随着元素掺杂量的增加以及氢气增湿,极化电阻减小。采用电解质支撑结构单电池进行发电实验,在800℃时,以Ce0.8Fe0.2O2-δ作为阳极的单电池最高功率密度可达98 mW.cm-2,表明该材料作为IT-SOFC的阳极材料具有一定的可行性,有望成为适合LSGM电解质的阳极材料。     

新型多孔氮化硼材料

多孔氮化硼材料是一种新型多孔非氧化物材料,具有高比表面积、可调孔径、良好的化学惰性和热稳定性等特点,在催化、储氢、气体吸附和分离等领域具有巨大的应用潜力,是材料领域研究热点之一。依孔径的不同,多孔氮化硼材料被分为微孔氮化硼、介孔氮化硼、大孔氮化硼和多级孔氮化硼。本文综述了微孔、介孔、大孔及多级孔等类型氮化硼材料的研究进展。重点介绍了不同类型氮化硼材料的制备和性能,并分析了各种制备方法的优缺点,最后探讨了多孔氮化硼材料的发展前景。     

Systhesis of double-hydrophilic core-shell type multiarm star copolymer polyethylenimine-block-poly(2-hydroxyethyl methacrylate

Multiarm star block copolymers hyperbranched polyethylenimine-b-poly(2-hydroxyethyl methacrylate) (HPEI-b-PHEMA) with average 28 PHEMA arms have been prepared by atom transfer radical polymerization (ATRP) of HEMA in a mixed solvent of methanol and water using a core-first strategy. The hyperbranched macroinitiator employed was prepared on the basis of well-defined hyperbranched polyethylenimine with Mw/Mn of 1.04 by amidation with 2-bromo-isobutyryl bromide. The polymerization condition was optimized to prepare star copolymers with narrow dispersity, and the variables included the volume ratio of methanol to water, the molar ratio of initiating site to CuCl and the molar ratio of [CuCl]:[CuBr2]. Under the optimized polymerization condition, the lowest Mw/Mn value of the obtained star copolymers was around 1.3. Kinetic analysis showed that an induction period existed in the polymerization of HEMA. After this induction period, a linear dependence of ln([M]0/[M]t) on time was observed. The obtained HPEI-b-PHEMA could adsorb hydrophilic molecules. The comparison with the star copolymer with hydrophobic core and hydrophilic PHEMA shell verified that both the hydrophilic core and shell could host the hydrophilic guests, but the amidated HPEI core was more effective than the PHEMA shell.     

重金属的生物吸附机理及吸附平衡模式研究*

各种生物吸附剂包括海洋微生物、发酵工业的菌丝体废渣及活性污泥的提取物等对金属离子的吸附特性已被广泛研究,本文就生物体对金属离子的吸附机理及吸附平衡模式研究进行了综述,阐明了今后的研究方向。