Asymmetric polymerization using C1 resources

Two examples of asymmetric alternating copolymerization, (1) the alternating copolymerization of α‐olefins (monosubstituted ethenes) with carbon monoxide and (2) the alternating copolymerization of meso‐epoxide with carbon dioxide, are described, and the meaning of chirality in polymer synthesis is emphasized. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 215–221, 2004     

二氧化碳和氧气的快速电化学方法联合测定

根据Ｏ２和ＣＯ２在二甲亚砜（ＤＭＳＯ）介质中Ｐｔ电极上的伏安特性，采用微电极并结构计算机控制的电位调制技术，建立了快速联合测定ＣＯ２和Ｏ２的调制电位脉冲库仑法和调制电位脉冲电流法，取得了满意的结果。一次测量时间快达４０ｍｓ。ＣＯ２检测范围０￣１０％（体积百分比）；Ｏ２检测范围不受限制。通过编程设计特定的调制电位－时间波形，可保持连续检测的长期稳定性。     

负载型TiO2-聚酰亚胺亲水复合膜的制备与分离性能

采用溶解－流涎法，湿相转换法和干湿相转换法制轩了负载型ＴｉＯ２－聚酰亚胺亲水复合膜，采用扫描电镜，红外光谱，压汞和透气性实验等手段对该膜的孔径分布，表面结构及扩散性能进行了表征，并讨论了制备亲水对膜孔结构的影响，实验结果表明，三种膜均具有很好的亲水性能，而干湿相转换膜具有良好的孔径分布和分离性能。     

Kinetic and computational studies on aminolysis of bicyclic carbonates bearing alicyclic structure giving alicyclic hydroxyurethanes

Aminolysis of bicyclic carbonates, which consist of five-membered cyclic carbonate and five- or six-membered alicyclic groups, was examined. Kinetic studies revealed that the aminolysis of the bicyclic carbonate with cyclohexane ring proceeded more smoothly than that of the bicyclic carbonate with cyclopentane ring. Computational calculation suggested that the different reaction rates originate from the distinct ring-strain of the cyclic carbonate groups affected by the conformation of the alicyclic groups.     

SciFinder-guided rational design of fluorescent carbon dots for ratiometric monitoring intracellular pH fluctuations under heat shock

Intracellular pH plays a significant role in various biological processes, including cell proliferation, apoptosis, metabolism, enzyme activity and homeostasis. In this work, a novel design strategy for the preparation of pH responsive carbon dots (CDs-pH) for ratiometric intracellular imaging was reported. By using SciFinder database, fluorescent CDs-pH with the required pK_a value of 6.84 were rationally designed, which is vital important for precise sensing of intracellular pH. As a result, the synthesized CDs-pH demonstrated robust ability to test pH fluctuations within the physiological range of 5.4-7.4. The CDs-pH was further utilized for fluorescent ratiometric imaging of pH in living HeLa cells, effectively avoided the influence of autofluorescence from native cellular species. Moreover, real-time monitoring of intracellular pH fluctuation under heat shock was successfully realized. This SciFinder-guided design strategy is simple and flexible, which has a great potential to be used for the development of other types of CDs for various applications.     

Preparation of Fluorine‐Doped Lead Dioxide Modified Electrodes for Electroanalytical Applications

The effect of F^? on the modified films of lead dioxide in morphology and structure was studied. The results obtained by cyclic voltammetry (CV), X‐diffractometer (XRD) and scanning electron microscope (SEM) techniques indicated that F^? could change the magnitude of lead dioxide crystal grain and the preferred crystallizing orientation on the substrate surface, even though it didn't change the basic structure of PbO₂. When the modified electrode was applied as an analytical sensor to determine phenolic compounds, the linearity was in the range of 2×10^?5 – 1×10^?3 mol/L and the detection limit was 2.5×10^?6 mol/L. It was all found that the stability and reproducibility of the oxide‐modified electrodes were improved by additional F^?.     

二氧化铈还原表面上水煤气变换反应机理

采用原位红外，程序升温脱附，脉冲表面反应技术研究了ＣｅＯ２还原表面在中温变换反应条件下表面物种的生成及脱附，并根据研究结果归纳出水煤气变换反应机理。     

四硫富瓦烯为介体的碳纤维束葡萄糖氧化酶微电极的研究

本文研究了一种将电子介体四硫富瓦烯(TTF,Tetrathiafulalene)引入葡萄糖氧化酶微电极的新方法,制成了TTF为介体的碳纤维束葡萄糖氧化酶微电极。该电极制作简单,响应迅速、灵敏,电极寿命可达15天。葡萄糖浓度在1。0×10~(-4)～1.5×10~(-3)mol/L范围内有线性关系。检出限为7×10~(-5)mol/L。用于人体血样中葡萄糖测定获得满意结果。     

Tertiary amine-mediated synthesis of microporous carbon membranes

Microporous carbon membranes were prepared on an -alumina support by a pyrolysis of cationic tertiary amine/anionic polymer composites. The precursor solutions contain a thermosetting resorcinol/formaldehyde (RF) polymer and a cationic tertiary amine. Three types of cationic tertiary amines with different chain lengths were used, such as tetramethlammonium bromide (TMAB), tetrapropylammonium bromide (TPAB) and cetyltrimethylammonium bromide (CTAB). A porous structure was produced by a decomposition of the amine and the resulting pores assisted the further gasification of the RF polymer at high temperature. The carbon/alumina membranes have thin and continuous carbon top layers with a thickness of 1 μm. Gas permeation tests were performed using single gases of CO₂, O₂, N₂, CF₄, n-C₄H₁₀ and i-C₄H₁₀, as well as binary mixtures of CH₄/n-C₄H₁₀ and N₂/CF₄ at different temperatures between 23 and 150 °C. The carbon membrane prepared using TMAB showed separation factors higher than 650 for the CH₄/n-C₄H₁₀ mixtures and higher than 8100 for the N₂/CF₄ mixture. From the permeation of pure gases with different molecular sizes, the pore sizes of the carbon membrane prepared using TMAB, TPAB and CTAB are estimated to be 4.0, 5.0 and larger than 5.5 Å, respectively, indicating that the micropore size of the carbon membranes is controllable by using different amines.     

Analysis to obtain precise density fluctuation of supercritical fluids by small-angle X-ray scattering

A procedure of analysis for small-angle X-ray scattering (SAXS) data has been established to obtain density fluctuation of supercritical fluids near the critical point. It is indispensable for the certain analysis to utilize both of high-quality SAXS data measured under stable thermodynamic condition and accurate P–ρ–T data in supercritical region. As a standard example, SAXS measurements have been performed for supercritical CO₂, which is a suitable sample satisfying the condition for both experiment and analysis. The measurements were carried out along four isothermal conditions at reduced temperature of T_r = T/T_c = 1.020, 1.022, 1.043 and 1.064. Comparing the experimental density fluctuation with calculated one from the most reliable equation of state, the differences are within 8% at most.