量热器阵列探测器

本工作研制出 5×25=125量热器阵列探测器。每个量热器单元是由石墨块与镍铬——镍铝热电偶构成。解决了热电偶丝与石墨块的粘接问题和上百条热电丝从真空室引出问题。创立了以液氮沸点温度为温度基点的新“0”点装置,它既具有温度稳定性能好又能解决各路之间的绝缘问题。为多路量热器mV级小讯号的物理测量奠定了基础。 采用Fy-1微机数据采集系统测量探测器的讯号。它性能稳定、采集速度快。测量了大面积二极管产生的电子束的均匀性,数据经过模拟处理,给出电子束空间分布的立体图像,从图可以清楚地看出电子束能量空间分布的非均匀性和轴向箍缩效应。     

Inhibitive detection of benzoic acid using a novel phenols biosensor based on polyaniline–polyacrylonitrile composite matrix

A novel sensitive and stable phenols amperometric biosensor, based on polyaniline–polyacrylonitrile composite matrix, was applied for determination of benzoic acid. The electrochemical biosensor functioning was based on the inhibition effect of benzoic acid on the biocatalytic activity of the polyphenol oxidase (PPO) to its substrate (catechol) in 0.1 M phosphate buffer solution (pH 6.5). A potential value of −50 mV versus SCE, and a constant catechol concentration of 20 μM were selective to carry out the amperometric inhibition measurement. The kinetic parameters Michaelis-Menten constant and maximum current (I_max) in the absence and in the presence of benzoic acid were also evaluated and the possible inhibition mechanism was deduced. The inhibiting action of benzoic acid on the polyphenol oxidase electrode was reversible and of the typical competitive type, with an apparent inhibition constant of 38 μM. This proposed biosensor detected levels of benzoic acid as low as 2 × 10⁻⁷ M in solution. In addition, the effects of temperature, pH value of solution on the inhibition and the interferences were investigated and discussed herein. Inhibition studies revealed that the proposed electrochemical biosensor was applicable for monitoring benzoic acid in real sample such as milk, yoghurt, sprite and cola.     

苯基取代的环戊二烯基锆化合物的合成及催化乙烯聚合

一系列苯基取代的环戊二烯配体在甲苯中相继与丁基锂及ZrCl4作用，生成相 应的苯基取代的茂金属化合物，通过^1H NMR，MS和元素分析表征了化合物的分子 结构，并研究了在MAO（甲基铝氧烷的助催化下，化合物对乙烯聚合的催化性能， 结果发现单苯基取代茂金属化合物的催化活性和产物聚乙聚的分子量都随聚合温度 的升高而增大。     

Asymmetric synthesis and antiviral activity of novel chiral amino-pyrimidine derivatives

By using a chiral cinchona alkaloid-squaramide catalyst, a series of both enantiomers of novel amino-pyrimidine derivatives can be obtained in an enantioselective three-component one-pot Mannich reaction with high yields and excellent enantioselectivities. In addition, these chiral derivatives were found to exhibit higher antiviral activities against tobacco mosaic virus (TMV) in vivo than the commercial agent ningnanmycin. In particular, chiral compounds (R)-4b and (R)-4e showed excellent antiviral activity against TMV at a concentration of 500?μg/mL, with a curative activity of 56.8% and 55.2%, respectively, a protection activity of 69.1% and 67.1%, respectively, and an inactivation activity of 91.5% and 94.3%, respectively. These values are superior to those of the agent ningnanmycin (which has curative, protective, and inactivation activities of 52.9%, 62.8%, and 90.4%, respectively). The antiviral mechanisms and enhanced antiviral activities of these chiral derivatives are interesting subjects for future investigation.     

Bi<Subscript>2</Subscript>O<Subscript>3</Subscript>/BiFeO<Subscript>3</Subscript> heterostructure: preparation,characterization, and photocatalytic activity

Bi₂O₃/BiFeO₃ composite was successfully fabricated by a conventional sol–gel method and structural properties were characterized based on X-ray diffractometer, scanning electron microscope, transmission electron microscope, energy-dispersive X-ray analyzer, nitrogen adsorption–desorption measurement, and UV–visible diffuse reflectance spectroscopy. Bi₂O₃/BiFeO₃ had a good absorption for visible light, which was benefit to photocatalytic activity. The highest degradation efficiency was obtained when the content of Bi₂O₃ in Bi₂O₃/BiFeO₃ was 63.9%. Effect of experimental conditions was investigated, and the highest photocatalytic activity of Bi₂O₃/BiFeO₃ was observed at photocatalyst dosage of 0.5 g/L, initial BPA concentration of 10 mg/L, and solution pH of 6.3. Bi₂O₃/BiFeO₃ photocatalyst exhibited enhanced photocatalytic activity for BPA, and the reaction rate constant over Bi₂O₃/BiFeO₃ composite was 2.23, 3.65, and 8.71 times higher than that of BiFeO₃, Bi₂O₃ and commercial TiO₂ (P25), respectively. Bi₂O₃/BiFeO₃ showed high photocatalytic activity after three cycles, suggesting that it was a stable photocatalyst. The possible photocatalytic mechanism has been discussed on the basis of the theoretical calculation and the experimental results. The hydroxyl and superoxide radicals together with photogenerated holes played significant roles in the photocatalytic reaction.     

新型抗菌高分子及其抗菌策略的研究进展

抗菌高分子具有丰富的分子结构和独特的抗菌机制。同时,对微生物具有低耐药性的倾向。这些特点使新型高分子材料在抗菌领域受到人们越来越多的关注。本文首先分析了细菌产生耐药性的原因及由其带来的严峻医学和社会问题;然后系统梳理并探讨了新型抗菌高分子材料（如树状大分子、嵌段共聚物、壳聚糖及其衍生物和抗菌高分子/纳米复合材料等）的结构特点和抗菌机理;最后展望了未来新型功能高分子在抗菌领域的重点延伸及探索方向。     

Promotional effect of Ce on the SCR of NO with NH<Subscript>3</Subscript> at low temperature over MnO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> supported by nitric acid-modified activated carbon

Different amounts of Mn and Ce oxides were loaded onto nitric acid-modified activated carbon (ACN) by wet impregnation. The series of catalysts were employed for the selective catalytic reduction of NO _x by NH₃ at temperatures between 100 and 250 °C. Cerium-modified catalysts exhibited higher de-NO _x performance than those modified with Mn/ACN, even with the same total loadings. The precursor solution with a molar ratio for Ce/(Mn + Ce) of 0.4 exhibited the highest catalytic activity. Enhanced resistance to SO₂ and H₂O and better stability were observed for 10%Mn–Ce(0.4)/ACN relative to 10%Mn/ACN. The catalysts were further characterized by N₂ physisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H₂-TPR), and temperature-programmed desorption of ammonia (NH₃-TPD). The N₂ physisorption and XRD results suggested that co-doping Ce with Mn increased the surface area and promoted the dispersion of Mn–Ce binary metal oxides. H₂-TPR the NH₃-TPD results demonstrated that the interaction between manganese oxide and cerium oxide species enhanced the redox and surface acidity of 10%Mn–Ce(0.4)/ACN.     

Boron and nitrogen dual-doped carbon as a novel cathode for high performance hybrid ion capacitors

A high performance hybrid ion capacitors has been developed by using B, N dual-doped 3D superstructure carbon cathode and prelithiated graphite anode.     

Preparation and characterization of antibacterial microporous membranes fabricated by poly(AMS-co-DMAEMA) grafted polypropylene via melt-stretching method

Functional polypropylene (PP) is prepared by graft poly(AMS-co-DMAEMA) onto PP chains through melt blending, and then microporous membranes of functional PP are made by casting and stretching, and finally the polycation microporous membranes are obtained via quaternization. The obtained microporous membranes show good hydrophilicity and antibacterial properties.     

吊片法测试液体表面张力的实验设计

表面张力是液体的重要物性数据,在科学研究、工业生产和日常生活中皆有广泛应用。介绍了采用吊片法测量液体表面张力的实验设计,该实验过程简单,准确度高,实验内容和时间易于调节,对于培养学生认真细致的科研作风有很大帮助。