添加Cl离子对V_2O_5-WO_3/TiO_2催化剂低温NO转化率的影响

考察添加不同含量Cl离子对浸渍法制备的Cl-V_2O_5-WO_3/TiO_2催化剂低温NO转化率的影响。随着Cl离子质量添加量从0增加到2.5%,Cl-V_2O_5-WO_3/TiO_2催化剂NO转化率先升高后降低,结合在含有SO_2和H2O的SCR实验结果,确定1.5%Cl-V_2O_5-WO_3/TiO_2为性能最优催化剂。在反应温度为149-362℃,NO转化率大于95%;在145-385℃,NO转化率大于90%。采用XRF、BET、XRD、TG、FT-IR和H2-TPR等方法表征了催化剂的物理化学性能和结构。结果表明,在反应气氛中加入SO_2和H2O后,催化剂比表面积和孔容均减小,副反应产物含有NH+4和SO_2-4。适量Cl离子可以抑制硫物种沉积,减少副反应产物生成,增强催化剂抗中毒能力。     

Applications of Modular Microfluidics Technology

Microfluidics has been widely used in the life science, analytical chemistry, environmental science and other fields in the recent years. Traditional microfluidics systems usually use a highly integrated system with multiple components for handling the fluid in the micro/nano scale. The design and fabrication of integrated microfluidics usually require highly sophisticated instruments and operation professionals. With the experience inherited from integrated circuit and micro electro mechanical system, the modular microfluidics system has been experienced a rapid development in recent years. Modular microfluidics system is a combination of a series of individual modules to achieve complicated liquid handling functions. Compared with conventional microfluidics approach, the modular microfluidics method has the potential in significantly reducing the fabrication cost by using the massive production of single chip, besides, it is easy to be operated, and the user can easily assembly the modules to obtain their customized microfluidics system. The concept of modular microfluidics also indicates the future development path for the standardization of microfluidics system and also provides a promising approach for the industrial massive production of microfluidics. However, the study of modular microfluidics is still in an early stage. Although lots of studies have been conducted with varies materials, fabrication methods and interface technologies, issues like modular interface still restricted the further development of microfluidics. In this paper, a comprehensive review for the latest research on the modular microfluidics and applications in biological and medical fields is provided, and the future research trends of modular microfluidics is also discussed.     

改性二氧化铅电极电氧化降解焦化废水

焦化废水中氨氮和COD(化学需氧量)无法通过生化处理达到排放和回用标准,采用改性二氧化铅电极(ESIXPb-I)对其进行电化学降解实现废水零排放,并考察了电流密度、初始pH值及氯离子浓度对降解的影响.研究结果表明,ESIXPb-I电极提高了Ti/PbO2电极的稳定性和析氧电位,显著降低了电荷转移电阻与膜电阻.ESIXPb-I电极降解焦化废水30 min后,氨氮与COD去除率均达到100;,该降解过程符合伪一级动力学.     

多层GaAlInP半导体发光材料的双晶衍射分析与拟合

应用双晶衍射仪对MOCVD外延生长所得到的一个GaAlInP双异质结(DH)的单晶多层结构进行测试与分析。应用双晶衍射的动力学理论模拟此样品的摇摆曲线，并结合界面的融合、晶格崎变与缺陷的散射来解释测试结果。对衍射谱的展宽提供了合理的解释，比较肯定地确定了此样品的结构与晶体质量。涉及缺陷对衍射FWHM的展宽的解释与关于缺陷的半动力学衍射理论相比，简单明了，实用于实际的生产检测。并根据分析结论对晶体质量的改进提供技术方案，改进了晶体质量。     

Synthesis and THF Accompanied Crystal Structure of 11H-Naphtho[1′,2′,:5,6]-pyrano[2,3-d]pyrimidin-11(10H)-one

8,9,12-Trihydro-9,9-pentamethylene-12-(3-nitrophenyl)-11H-naphtho[1′,25,6] pyrano[2,3-d]pyrimidin-11(10H)-one 1, another conversion product of Friedl(a)ndler reaction, has been synthesized by the reaction of 2-amino-4-(3-nitrophenyl)-4H benzo[f]chromene-3-carbo- nitrile 2 with cyclohexanone in the presence of Lewis acid catalysts. The crystal of the title compound 1 THF solvate, C60H62N6O10, was obtained and determined by X-ray diffraction me- thod. The crystal is of triclinic, space group P with a = 11.4633(11), b = 12.6247(12), c = 19.658(2)(A), α = 72.642(8), β = 89.045(9), γ = 68.340(5)°, V = 2509.6(4), Z = 2, Dc = 1.359 g/cm3, F(000) = 1088, Mr = 1027.16, the final R = 0.0674 and wR = 0.1869 with I > 2σ(I) and the goodness-of-fit S = 1.045 on F2. The pyrimidine ring has an envelope conformation, linked with a six-membered ring through a spiro C atom. The crystal packing of 1 THF solvate is stabilized by N-H…O hydrogen bonds, and π-π stacking interaction occurs between two adjacent nearly planar molecules of 1.     

Novel Flower‐Like Ag‐SiO2‐MgO‐Al2O3 Material: Preparation,Characterization and Catalytic Application in Methanol Dehydrogenation

Catalytic direct dehydrogenation of methanol to formaldehyde was carried out over Ag‐SiO₂‐MgO‐Al₂O₃ catalysts prepared by sol‐gel method. The optimal preparation mass fractions were determined as 8.3% MgO, 16.5% Al₂O₃ and 20% silver loading. Using this optimum catalyst, excellent activity and selectivity were obtained. The conversion of methanol and the selectivity to formaldehyde both reached 100%, which were much higher than other previously reported silver supported catalysts. Based on combined characterizations, such as X‐ray diffraction (XRD), scanning electronic microscopy (SEM), diffuse reflectance ultraviolet‐visible spectroscopy (UV‐Vis, DRS), nitrogen adsorption at low temperature, temperature programmed desorption of ammonia (NH₃‐TPD), desorption of CO₂ (CO₂‐TPD), etc., the correlation of the catalytic performance to the structural properties of the Ag‐SiO₂‐ MgO‐Al₂O₃ catalyst was discussed in detail. This perfect catalytic performance in the direct dehydrogenation of methanol to formaldehyde without any side‐products is attributed to its unique flower‐like structure with a surface area less than 1 m²/g, and the strong interactions between neutralized support and the nano‐sized Ag particles as active centers.     

水中微量芘和荧蒽的胶束增敏荧光分析法同时测定

建立了吐温-20(Tween-20,Tw-20)直接荧光法同时测定水中溶解态芘(pyrene,Py)和荧蒽(fluoranthene,FLuA)的方法.该法测定芘和荧蒽的线性范围分别为1.98×10-10 ～9.88×10-8 mol/L和2.00×10-9 ～7.99×10-7 mol/L,检出限分别为9.88×10-11 mol/L和5.99×10-10 mol/L.方法灵敏,用于自来水、江水样的分析,取得了良好的效果,芘的回收率分别为92%～102%和101%～102%,荧蒽的回收率分别为90%～100%和94%～111%.为预测和治理水污染提供了一种灵敏、快速且简便的测试手段.     

Photoluminescence and Electroluminescence of Organic Light Emitting Diodes Based on Tris‐(8‐quinolinolato) Aluminum Nanoparticles

利用共沉淀方法制备出平均粒径为20nm的有机物8-羟基喹啉铝纳米粒子,8-羟基喹啉铝纳米粒子呈球形且粒度不随老化时间的增加而改变。本文研究了8-羟基喹啉铝纳米粒子的光致发光及基于8-羟基喹啉铝纳米粒子制作的电致发光器件的电致发光特性。8-羟基喹啉铝形成纳米粒子后,其光致发光及电致发光发射光谱的谱峰均出现蓝移。随着驱动电压的增加,器件中8-羟基喹啉铝纳米粒子的发射峰逐渐红移。在驱动电压为16伏时,8-羟基喹啉铝纳米粒子器件的最大亮度达600cd/m²,电流密度为150mA/cm^-2时,器件的发光效率为0.19cd/A。基于8-羟基喹啉铝纳米粒子器件的发射光谱证实了AlQ₃纳米粒子具有量子尺寸效应的存在,这为有机纳米电致发光器件的研究开辟了一条新的研究路线,同时也为那些传统的有机材料如有机分子晶体的基础研究探索出新的研究方向。     

曙红B共振光散射法测定微量的盐酸异丙嗪

研究了染料曙红B与盐酸异丙嗪的结合反应.在pH=3.50的Walpole介质中,曙红B本身的共振光散射信号较弱,与盐酸异丙嗪结合形成离子缔合物后,体系的共振光散射明显增强,并且光散射增强强度与盐酸异丙嗪在一定浓度范围内成正比,据此建立了一种高灵敏测定盐酸异丙嗪的方法.在体系的最大散射波长363 nm处,测得盐酸异丙嗪的线性范围为7.5×10-8～4.5×10-6 g/mL,检测限为1.8×10-8 g/mL,用于盐酸异丙嗪片剂、针剂、人血清及尿样中盐酸异丙嗪的测定,结果令人满意.     

吡啶基团的对称性和离子化对分子双光子吸收截面的影响

采用超快速激光光谱方法研究了含吡啶基团的四个联苯乙烯衍生物及两个杂环分子(A: 4,4’-二(2-(4-吡啶基)乙烯)联苯; B: 4,4’-二(2-(2-吡啶基)乙烯)联苯; C: 1-甲基-4-(2-(4’-(2-(4-吡啶基)乙烯基)-4-联苯)乙烯基)吡啶碘盐; D: 1-甲基-2-(2-(4’-(2-(2-吡啶基)乙烯基)-4-联苯)乙烯基)吡啶碘盐; E: 4-(2-(9-丁基-9氢-3-咔唑)乙烯基)-1-甲基吡啶碘盐; F: 4-(2-(9-丁基-9氢-3-咔唑)乙烯基)-1-甲基喹啉碘盐)的结构-性能关系. 实验结果显示双光子吸收截面最大的是分子E, 高达617.3 GM; 最小的是分子B, 为19.3 GM(1 GM=10^-50 cm⁴·s·photon^-1). 实验研究结果表明, 分子中吡啶基团的对称性及其离子化对分子双光子吸收截面起很重要的作用; 进一步用理论计算证实了以上实验结论并对其机制进行了分析讨论.