NiY分子筛的合成及在微生物电解池阴极的析氢性能研究

在Na₂O-Al₂O₃-SiO₂-H₂O体系中添加硝酸镍,采用导向剂法合成了NiY分子筛。利用XRD、SEM、TEM、N₂吸附-脱附等手段对合成的NiY分子筛进行了表征。结果表明,随着镍添加量的增加,结晶度和zeta电位呈先增大后减小的趋势。当Si/Ni （mol ratio）大于5时,硝酸镍对分子筛的形成具有促进作用,当Si/Ni （mol ratio）小于5时,则具有抑制作用。晶粒粒径为1.5-3 μm,形貌为凹槽结构的六方或四方柱型,且具有微孔-介孔多级孔道结构特征。通过循环伏安曲线和极化曲线测试,在Si/Ni （mol ratio）=5时,样品的氧化还原性能最强,过电势最小,电催化活性最高。在12 h内,每4 mg的Si/Ni （mol ratio）=5样品,产气总量为10.1 mL,氢气纯度达81.69%,与Pt电极相比其氢气产量提高了28%。NiY分子筛表现出良好的析氢催化活性,有望取代Pt成为MEC新型阴极材料。     

Preparation of bovine hemoglobin-imprinted polymer beads via the photografting surface-modified method

Molecularly imprinted polymers (MIPs), based on photografting surface-modified polystyrene beads as matrices, were prepared with acrylamide as the functional monomer, bovine hemoglobin as the template molecule and N, N′-methylene bisacrylamide as the crosslinker in a phosphate buffer. The results of IR, scanning electron microscope (SEM) and elemental analyses demonstrated the formation of a grafting polymer layer on the polystyrene-bead surface. Subsequent removal of the template left behind cavities on the surface of the polymer matrix with a shape and an arrangement of functional groups having complementary binding sites with the original template molecule. The adsorption studies showed that the imprinted polymers have a good adsorption capacity and specific recognition for bovine hemoglobin as the template molecule. Our results demonstrated that the polymer prepared via the photografting surface-modified method exhibited better selectivity for the template. Attempts to employ the new method in molecular imprinting techniques may introduce new applications for MIPs and facilitate probable protein separation and purification. __________ Translated from Chemical Journal of Chinese Universities, 2008, 29(1): 64–70     

An inexpensive, portable and microcontrolled near infrared LED-photometer for screening analysis of gasoline

A microcontrolled, portable and inexpensive photometer is proposed. It uses a near infrared light emitting diode (NIR LED) as radiation source, a PbSe photoresistor as infrared detector and a programmable interrupt controller (PIC) microcontroller as control unit. The detector system presents a thermoresistor and a thermoelectric cooling to control the detector temperature and keep the noise at low levels. The microcontroller incorporated total autonomy on the proposed photometer. As its components are inexpensive and of easy acquisition, the proposed NIR LED-photometer is an economical alternative for chemical analyses in small routine, research and/or teaching laboratories. By being portable and microcontrolled, it also allows carrying out field chemical analyses. The instrument was successfully applied on the screening analysis to verify adulteration in gasoline samples.     

Novel Strong Cation‐exchange Monolithic Column Using Poly(vinyl ester resin) as Stationary Phase Materials for Lysozyme Separation by HPLC

本实验合成了一种以聚乙烯基酯树脂为原料的聚合物整体柱。在聚合反应中,聚乙烯基酯树脂在聚合中既作为单体同时也作为交联剂,偶氮二异丁腈作为引发剂,十六醇为致孔剂。聚合物制得后以扫描电镜考察了该聚合物的内部形态。同时联合高效液相色谱分别考察了该整体柱的分离能力和载样量。在分离实验中,考察了流动相的浓度及pH值对分离效果的影响。结果表明,溶菌酶可成功的从鸡卵清中分离出,并在较短的时间内取得了较好的分离效果。     

利用傅立叶变换红外光谱法检测一氧化氮纯气中的氧化亚氮杂质

利用傅立叶变换红外光谱法对一氧化氮纯气中的氧化亚氮进行了定性和定量分析。实验结果显示,在恒定条件下进样,分辨率为0.5cm^-1,扫描512次,选择2270～2130cm^-1范围内的特征吸收进行定量分析时可以得到良好的分析结果。利用双点法对氧化亚氮杂质进行定量计算;并对分析结果进行了严格的不确定度评定,为一氧化氮纯气中氧化亚氮的检测提供了一个全新的方法。     

Folding kinetics of a naturally occurring helical peptide: implication of the folding speed limit of helical proteins

The folding mechanism and dynamics of a helical protein may strongly depend on how quickly its constituent alpha-helices can fold independently. Thus, our understanding of the protein folding problem may be greatly enhanced by a systematic survey of the folding rates of individual alpha-helical segments derived from their parent proteins. As a first step, we have studied the relaxation kinetics of the central helix (L9:41-74) of the ribosomal protein L9 from the bacterium Bacillus stearothermophilus , in response to a temperature-jump ( T-jump) using infrared spectroscopy. L9:41-74 has been shown to exhibit unusually high helicity in aqueous solution due to a series of side chain-side chain interactions, most of which are electrostatic in nature, while still remaining monomeric over a wide concentration range. Thus, this peptide represents an excellent model system not only for examining how the folding rate of naturally occurring helices differs from that of the widely studied alanine-based peptides, but also for estimating the folding speed limit of (small) helical proteins. Our results show that the T-jump induced relaxation rate of L9:41-74 is significantly slower than that of alanine-based peptides. For example, at 11 degrees C its relaxation time constant is about 2 micros, roughly seven times slower than that of SPE(5), an alanine-rich peptide of similar chain length. In addition, our results show that the folding rate of a truncated version of L9:41-74 is even slower. Taken together, these results suggest that individual alpha-helical segments in proteins may fold on a time scale that is significantly slower than the folding time of alanine-based peptides. Furthermore, we argue that the relaxation rate of L9:41-74 measured between 8 and 45 degrees C provides a realistic estimate of the ultimate folding rate of (small) helical proteins over this temperature range.     

Thiol-functionalized Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/SiO<Subscript>2</Subscript> microspheres with superparamagnetism and their adsorption properties for Au(III) ion separation

Thiol-functionalized Fe₃O₄/SiO₂ microspheres (Fe₃O₄/SiO₂-SH) with high saturation magnetization (69.3 emu g^–1), superparamagnetism, and good dispersibility have been prepared by an ethylene glycol reduction method in combination with a modified Stöber method. The as-prepared composite magnetic spheres are characterized with fourier transform infrared spectroscopy (FT-IR), zeta potential, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and superconducting quantum interference magnetometer, and tested in separation of Au(III) ions from aqueous solutions. The data for Au(III) adsorption on Fe₃O₄/SiO₂-SH are analyzed with the Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherm models, and the pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetics models. The adsorption behaviors of Au(III) on Fe₃O₄/SiO₂-SH follow the Langmuir isotherm model, and the adsorption process conforms to the pseudo-second-order kinetic model. The maximum adsorption capacity of Au(III) on Fe₃O₄/SiO₂-SH is 43.7 mg g^–1. Acetate anions play an important role yet Cu(II) ions have little interference in the adsorption of Au(III) on the adsorbent. A satisfactory recovery percentage of 89.5% is acquired by using an eluent with 1 M thiourea and 5% HCl, although thiols have a high affinity to Au(III) ions based on the hard-soft acid-base (HSAB) theory by Pearson.     

两亲分子聚集相的扫描隧道显微镜研究

用最近发展起来的局域探测手段－扫描隧道显微镜（ＳＴＭ）及其相伴的方法如局域功函数等，对具有十分丰富局域结构的两亲分子和水的两系统的聚集相作了初步研究，以期为两亲分子研究及局域化学的发展添砖加瓦，结果表明由ＳＴＭ可以真实对反映出各种聚集相的不同形貌，而且加上局域功函数像还可以揭示两亲分子的头尾取向，这对有机分子系统的局域结构的研究有普遍意义。