离子电解质电化学还原CO_2行为研究

本文通过简单的亲核加成制备出一种新型的离子电解质—1-二乙二醇甲醚基-3-甲基咪唑甘氨酸盐,并对其电化学CO2转化为CO行为进行了研究。研究结果表明,样品可以在较低过电位下实现CO2到CO的转化,并且样品可以重复使用,电化学还原性能不会明显降低。     

卵磷脂对甲烷水合物形成的影响

建立了用于测定卵磷脂(lecithin)对钻井液中水合物形成影响的实验装置及方法,以理解化学添加剂卵磷脂对北极Cascade地区钻井过程中水合物层的稳定作用。本研究旨在理解卵磷脂对纯水中甲烷水合物形成热力学和动力学的影响。结果表明,卵磷脂基本上不影响甲烷水合物生成的热力学条件,但当卵磷脂在水中的浓度超过0.003 g·g^-1时,它会影响甲烷水合物的生成速度和数量,是很好的水合物生成动力学促进剂。     

含水量对硅胶柱层析同时分离纯化卵磷脂和脑磷脂的影响

研究了固定相初始含水量和流动相含水量对硅胶柱层析同时分离纯化卵磷脂和脑磷脂的影响。结果表明：含水量对硅胶柱层析同时分离纯化卵磷脂和脑磷脂有显著的影响。硅胶初始含水量在10％、12％(wt)和流动相含水量在0．5％0．9％(vol)范围内,卵磷脂(PC)和脑磷脂(PE)可实现基线分离,PC的回收率可达85％以上,PE的回收率可达70％以上。本研究结果对高纯度卵磷脂和脑磷脂的制备有一定的指导作用。     

维生素E和卵磷脂自配复合物对油脂的抗氧化作用

通过测定油脂在加速氧化过程中过氧化值的变化,发现维生素E和卵磷脂复合物对油脂具有良好协同抗氧化作用。     

含水量对氧化铝柱色谱法同时分离纯化卵磷脂和脑磷脂的影响

系统地研究了固定相初始含水量和流动相含水量对氧化铝柱色谱法同时分离纯化卵磷脂和脑磷脂的影响.结果表明：在实验范围内,氧化铝的初始含水量对氧化铝柱色谱法同时分离纯化卵磷脂和脑磷脂有很大的影响,而流动相含水量则影响不大.氧化铝初始含水量在8%(质量分数)和流动相含水量在0.1%～1.1%(体积分数)范围内,卵磷脂和脑磷脂可实现基线分离,PC的回收率可达90%以上,PE的回收率可达40%以上.并对实验结果的重现性进行了考察.研究结果除了对卵磷脂和脑磷脂的精制有一定的指导作用外,对其他天然产物分离纯化的研究和生产也有一定的借鉴意义.     

溶剂对荧光分子发光行为的影响

本文通过测试一系列含吡啶三苯胺多枝化合物在不同条件下的光学性能的研究,通过对溶剂的特定配比对荧光分子发光性能的研究,探索了能量的转移以及所涉及的对Stern-volmer方程内容的部分修正。初步研究结果表明,在光照下该体系内发生电荷转移而非电子或能量转移,并在双光子聚合条件下由该体系获得一幅光子晶体微结构图。     

锂含量与烧结时间对固体电解质Li7La3Zr2O12电导率的影响

具有石榴石结构的固体电解质Li7La3Zr2O12在室温下即可呈现出较高的离子电导率。采用固相反应法,通过在原料中调控不同的锂源含量,以及经历不同的烧结时间,探索了上述制备工艺条件对样品室温离子电导率的影响规律。结果表明：采用不同的锂含量均可获得立方石榴石结构;当混合原料中的锂源采用–3%Li含量时,可以获得最高电导率(2.11×10–4 S/cm);对于不含锂过量的原料,当烧结时间为30 h时,可以获得最高电导率2.03×10–4 S/cm。这些结果表明Li7La3Zr2O12在全固态锂离子电池中具有广阔的应用前景。     

原位聚合二胺盐液晶单体及其聚合物电化学性能的研究

以苯甲酸联苯酯为基元,制备二胺盐液晶单体。对液晶单体紫外光致原位聚合制备出具有离子传导功能的聚合物。通过FT IR和~1H NMR对其结构进行了表征。通过电化学工作站测试其电阻并计算出不同温度下的离子传导率。结果表明,由于液晶态下分子结构的有序排列,二胺盐液晶单体在液晶态的传导率高于固态的传导率,并且传导率随着温度的升高而上升,在170℃达到最大值,为1.30×10~(-5)S/cm。二胺盐聚合物在95℃下传导率达到1.02×10~(-5) S/cm。通过原位聚合使聚合物保留单体在液晶态时的分子有序排列,获得在中低温条件下传导率接近液晶相下传导率的聚合物材料。     

DDBA改性纤维对PEO聚合物电解质性能的影响

针对聚环氧乙烷(PEO)基聚合物电解质室温易结晶的问题,将4-4-二羟基-α,α’-二甲基卞联氮(DDBA)改性芳纶纤维(DF)掺杂在基体中,抑制PEO结晶,提高其离子电导率。通过交流阻抗、差式扫描量热等方法进行表征。结果表明：制备的聚合物电解质在少量DF掺杂时离子电导率有所改善,其中掺杂质量分数2.0%DF的电解质电化学性能最好,在25℃下电导率达到1.5×10^-5 S/cm,离子迁移数提高至0.30。     

Orientation of the OmpF Porin in Planar Lipid Bilayers

The outer‐membrane protein OmpF is an abundant trimeric general diffusion porin that plays a central role in the transport of antibiotics and colicins across the outer membrane of E. coli. Individual OmpF trimers in planar lipid bilayers (PLBs) show one of two current–voltage asymmetries, thus implying that insertion occurs with either the periplasmic or the extracellular end first. A method for establishing the orientation of OmpF in PLB was developed, based on targeted covalent modification with membrane‐impermeant reagents of peripheral cysteine residues introduced near the periplasmic or the extracellular entrance. By correlating the results of the modification experiments with measurements of current asymmetry or the sidedness of binding of the antibiotic enrofloxacin, OmpF orientation could be quickly determined in subsequent experiments under a variety of conditions. Our work will allow the precise interpretation of past and future studies of antibiotic permeation and protein translocation through OmpF and related porins.     

Orientation of the Monomeric Porin OmpG in Planar Lipid Bilayers

Outer membrane protein G (OmpG) is a non‐selective porin from Escherichia coli. OmpG is a monomer, which makes it unusual among porins, and suggests that it may be useful in biotechnology. In planar lipid bilayers, individual OmpG pores reconstituted by insertion from detergent exhibit pronounced asymmetry in current‐voltage relationships and voltage‐dependent gating. Here, this asymmetry is used to deduce the orientation of OmpG in the bilayers. We introduced two cysteines into the extracellular loops of OmpG. Cleavage of the disulfide bond formed by these residues significantly increases spontaneous gating of the pore. By adding DTT to one side of the bilayer or the other, we demonstrated that pores showing a quiet trace at negative potentials have a “trans” conformation (extracellular loops on the trans side of the bilayer), while pores showing a quiet trace at positive potentials have a “cis” conformation (extracellular loops on the cis side). With this knowledge, we examined the binding of a cyclodextrin to OmpG. When the cyclodextrin was presented to the extracellular face of the pore, transient multisite interactions were observed. In contrast, when the cyclodextrin was presented to the periplasmic face, a more stable single‐site interaction occurred. Because the cyclodextrin can act as a molecular adapter by binding analytes, this information serves to advance the use of OmpG as a biosensor.     

多孔硅支撑磷脂双层膜的制备与表征

制备了一种以多孔硅为基底的新型支撑磷脂双层膜,多孔硅具有良好的光反射干涉性能,在多孔硅表面构筑磷脂双分子层膜有望形成一类新型的生物传感器.通过电化学刻蚀法制备了孔径为35～45 nm,孔道深度约为15μm的多孔硅,并用电子显微镜观测了其孔道结构,经原子力显微镜检测,其表面均方根粗糙度(RMSR)仅为0.64nm.用挤出...     

传热表面对电解质溶液中CaSO4结垢过程的影响

引　言本研究是在前人研究[1～ 4 ] 的基础上 ,考察经现代表面处理技术处理后即经过离子注入或磁控溅射技术对加热器表面处理后该表面的抗垢性能 ,并通过对污垢层的显微拍照进一步阐述了加热器表面状况对污垢形成过程的影响 ,并将所得结果与未处理的加热器表面所获得的结果进行比较 ,以决定离子注入和磁控溅射的表面处理技术抗垢程度的适用性 .研究表明 ,经离子注入和磁控溅射后的表面具有良好的抗垢性能 .1　实验装置与研究方法1.1　实验装置和数据采集系统实验装置参见文献 [1].数据采集系统使用ＯＭＥＧＡＤＡＳ - 8通道 ,12个节点 ,模拟…     

溶剂及TiO2纳米粒子对血红蛋白电子传递的影响

系统考察了血红蛋白分子(Hb)在石墨电极上的直接电子传递性质,结果表明有机溶剂二甲亚砜(DMSO)、表面活性物质双十二烷基二甲基溴化铵(DDAB)及纳米粒子(TiO2)均可改善血红蛋白与电极之间的直接电子传递。在0.1 mol.L-1pH=7.0的PBS缓冲溶液中,固定化Hb显示了一对稳定的峰形对称的氧化还原峰,在扫速为100 mV/s时其电子传递速率常数为3.4 s-1,在20到500 mV/s的扫速范围内,电极响应是一个表面控制过程,其式量电位为Hb/TiO2/DMSO/PG的-(296±8)mV和Hb/TiO2/DDAB/PG的-(172±6)mV(vs.Ag/AgCl)。     

工艺条件对镁合金微弧氧化陶瓷层孔隙率的影响

利用微弧氧化技术在AZ91D镁合金表面原位生长陶瓷膜,通过调节电解液浓度、控制起弧电压,以探索减少陶瓷层中孔洞及孔径的工艺方法.结果表明:选择合适的电解液的浓度可以减少陶瓷层中孔隙,控制微弧氧化过程中的起弧电压也可以减少陶瓷层中的孔隙和孔径.     

The Effect of the Osmotically Active Compound Concentration Difference on the Passive Water and Proton Fluxes across a Lipid Bilayer

The molecular details of the passive water flux across the hydrophobic membrane interior are still a matter of debate. One of the postulated mechanisms is the spontaneous, water-filled pore opening, which facilitates the hydrophilic connection between aqueous phases separated by the membrane. In the paper, we provide experimental evidence showing that the spontaneous lipid pore formation correlates with the membrane mechanics; hence, it depends on the composition of the lipid bilayer and the concentration of the osmotically active compound. Using liposomes as an experimental membrane model, osmotically induced water efflux was measured with the stopped-flow technique. Shapes of kinetic curves obtained at low osmotic pressure differences are interpreted in terms of two events: the lipid pore opening and water flow across the aqueous channel. The biological significance of the dependence of the lipid pore formation on the concentration difference of an osmotically active compound was illustrated by the demonstration that osmotically driven water flow can be accompanied by the dissipation of the pH gradient. The application of the Helfrich model to describe the probability of lipid pore opening was validated by demonstrating that the probability of pore opening correlates with the membrane bending rigidity. The correlation was determined by experimentally derived bending rigidity coefficients and probabilities of lipid pores opening.     

Ni-SiC纳米复合电镀工艺与镀液均镀能力

文章主要研究了Ni-SiC纳米复合电镀工艺条件对镀液均镀能力的影响。研究表明:要获得好的分散能力和均镀能力,镀液的搅拌强度既不能太大,也不能太小,应保持适中;镀液中纳米SiC微粒浓度和镀液pH对均镀能力影响不显著,但pH不能过高;温度则应控制在40～50℃。此外,整平能力试验表明在镀液中加入纳米微粒,出现负整平作用。电化学极化曲线表明镀液中存在少量纳米微粒,可增大阴极极化,有利于得到结晶细致、光亮平整的镀层。     

高浓度锂盐电解质的研究进展

电解质作为锂电池离子传导的重要介质,对于提升锂电池循环稳定性能、安全性能等方面起着至关重要的作用,而锂盐作为其电解质(电解液)的关键组分,当锂盐浓度较低时,存在易燃性高、热稳定性差、电极反应动力学缓慢等缺点,而高浓度锂盐电解质具有热力学稳定性良好,Li+在电极上可进行可逆嵌入/脱出反应,离子载体密度较高,溶剂挥发性降低,提高SEI膜的热稳定性和抑制Al集流体腐蚀等优点,但也存在离子电导率低、润湿性差和材料成本高等问题,限制了商业化应用.概述了新型锂盐、高浓度锂盐电解质研究历程、溶剂化结构对界面性质的影响及高浓度电解质在锂电池体系中的应用,为解决高浓度锂盐电解质的局限性和加快商业化应用提供一些思路.