废水生物脱氮工艺中N2O排放数学模型研究进展

N_2O是一种重要的温室气体,而污水生物脱氮处理过程是N_2O的潜在产生源之一。随着污水处理量和处理程度的不断提高,N_2O的排放量也将不断增大。建立N_2O排放数学模型对污水生物脱氮系统中N_2O生成机制的深入研究和污水处理行业N_2O削减工艺技术的开发具有重大的理论及实践意义。本文归纳了生物脱氮工艺的原理,系统阐述了生物脱氮工艺中N_2O的生成机理和排放数学模型的类型、建立方法及应用情况。在此基础上,对生物脱氮工艺中N_2O排放数学模型的研究现状和研究方向进行了总结和展望,以期为N_2O排放数学模型的完善、N_2O排放量的削减、污水生物脱氮工艺的优化及污水处理行业的可持续发展提供理论基础和科学依据。     

Fluorene-containing tetraphenylethylene molecules as lasing materials

A series of star-shaped oligofluorene molecules, each containing a TPE core, have been specifically designed and produced to show effective aggregation-induced emission (AIE). Each molecule differs either in the number of fluorene units within the arms (e.g., 1 or 4, compounds 4 and 5 ), or the terminal group positioned at the end of each arm (e.g., H, TMS, or TPA, compounds 4 , 6 , and 7 ). Although they are all poor emitters in solution phase they become efficient yellow-green luminogens in the condensed state. Their AIE properties were investigated in THF/H₂O mixtures, with each molecule exhibiting a clear emission enhancement at specific water contents. An all-organic distributed feedback (DFB) laser was fabricated using compound 4 as the gain material and exhibited an average threshold energy fluence of 60 ± 6 μJ/cm² and emission in the green region. Furthermore, piezofluorochromism studies on a thin film of this material displayed a linear dependence of the amplified spontaneous emission (ASE) peak position on applied pressure, indicating potential applications as lasing-based pressure sensors. © 2016 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 734–746     

悬浮液直接进样ICP–OES法测定高纯氧化铝中的铁、钛、硅、铬

采用悬浮液直接进样电感耦合等离子体发射光谱法(ICP–OES)测定高纯氢氧化铝中铁、钛、硅、铬的含量。悬浮液用电磁搅拌器搅拌,均匀地分散在溶液中,通过仪器蠕动泵进入雾化室,均匀无阻地导入ICP光源。Fe,Ti,Si,Cr的分析谱线分别为259.940,336.112,251.611,205.552 nm;RF功率为1 300W,等离子体气流量为13.0 L/min,雾化器气体流量为0.60 L/min,辅助气流量为1.00 L/min。Fe,Ti,Si,Cr的质量浓度分别在0.0~30.0,0.0~15.0,0.0~90.0,0.0~15.0μg/m L范围内与信号强度呈良好的线性,线性相关系数均大于0.999,方法的检出限为0.027 6~0.993 9μg/m L,测量结果的相对标准偏差为0.65%~6.84%(n=11),回收率为95.0%~104.8%。该法抗干扰能力强、线性范围宽,适用于高纯氢氧化铝中铁、钛、硅、铬含量的分析。     

Influence of the Oxide Content in the Catalytic Power of Raney Nickel in Hydrogen Generation

The influence of oxides in the hydrogen evolution on Raney nickel electrocatalysts was characterized by electrochemical impedance measurements. In addition, these materials show competitive overpotentials for hydrogen evolution with a modified Watts bath as a binder for the Raney nickel. The optimum result was ?190?mV of overpotential at 100?mA?cm^?2. Oxygen in the Raney Ni catalyst affects its electroactivity toward hydrogen evolution. The source of oxygen is related to the presence of chloride ions in the modified Watts bath. A Watts bath binds Raney Ni particles to the surface of the catalysts and chloride regulates the oxygen content in the nickel binder during electrodeposition. High oxygen content increases the hydrogen evolution overpotential of the electrode. The electroactivity of the synthesized porous coatings was evaluated by polarization curves and impedance plots. In addition, surface characterization by X-ray diffraction, field emission–scanning electron microscopy equipped with energy-dispersive analysis, and X-ray photoelectron spectroscopy is reported.     

Coumarin-based urea-amide scaffold in ratiometric fluorescence sensing of CN−

Coumarin-based urea and urea–amide scaffolds 1–3 have been designed and synthesized for the selective and naked eye detection of cyanide ion. Of the three, compound 3 exhibits ratiometric fluorescence change selectively in the presence of CN^? and validates the rationality in designing anion receptor. Upon interaction with CN^?, the color of the solution of 3 in CH₃CN under UV exposure becomes bright yellow, which is beneficial for its naked eye detection. Addition of CN^? of ～10^?4 M brings nice color change from colourless to yellow in ordinary light. The sensing event is supposed to be due to nucleophilic addition of CN^? to the coumarin unit enabling intramolecular charge transfer (ICT) mechanism.     

A novel water-soluble AIE-based fluorescence probe with red emission for the sensitive detection of heparin in aqueous solution and human serum samples

Heparin is widely used to anticoagulation treatment in clinic, while the overdoses of heparin can cause potentially catastrophic complications. Thus, the selective and sensitive detection of heparin is of great importance. Herein, a novel water-soluble AIE-based fluorescent probe (TIBI) with red emission (650 nm) has been rationally developed to detect heparin by the electrostatic-interaction and ion replacing strategy. TIBI exhibited excellent selectivity and low detection limit (0.08 μM) for detection of heparin. Moreover, TIBI was successfully applied to detect heparin in complicated serum samples with satisfactory results. This study holds great promise for real time monitoring heparin in clinical application.     

3D Laser Micro‐ and Nanoprinting: Challenges for Chemistry

3D printing is a powerful emerging technology for the tailored fabrication of advanced functional materials. This Review summarizes the state‐of‐the art with regard to 3D laser micro‐ and nanoprinting and explores the chemical challenges limiting its full exploitation: from the development of advanced functional materials for applications in cell biology and electronics to the chemical barriers that need to be overcome to enable fast writing velocities with resolution below the diffraction limit. We further explore chemical means to enable direct laser writing of multiple materials in one resist by highly wavelength selective (λ‐orthogonal) photochemical processes. Finally, chemical processes to construct adaptive 3D written structures that are able to respond to external stimuli, such as light, heat, pH value, or specific molecules, are highlighted, and advanced concepts for degradable scaffolds are explored.     

Trichalcogenasumanene ortho‐Quinones: Synthesis,Properties, and Transformation into Various Heteropolycycles

The regioselective transformation of heterobuckybowl trichalcogenasumanenes 1 a , b at peripheral butoxy groups afforded trichalcogenasumanene ortho ‐quinones 2 a , b . Compounds 2 a , b are distinct from 1 a , b in terms of their molecular geometry and electronic state; that is, they have a shallower bowl depth and show absorbance in the NIR region. The reaction of 2 a , b with diamines resulted in a variety of heteropolycycles, including molecular spoon 3 a – 6 a , planar π‐systems 3 b – 6 b , and highly twisted [7‐6‐6]‐fused systems 7 a , b . These new heteropolycycles had different optical/electrical properties: 4 a,b showed hole mobility of approximately 0.002 cm² V⁻¹ s⁻¹, 6 a displayed red emission in both solution and the solid state, and 7 a , b formed tight stacks of the curved π‐surface.     

Non‐Doped Sky‐Blue OLEDs Based on Simple Structured AIE Emitters with High Efficiencies at Low Driven Voltages

Blue organic light‐emitting diodes (OLEDs) are necessary for flat‐panel display technologies and lighting applications. To make more energy‐saving, low‐cost and long‐lasting OLEDs, efficient materials as well as simple structured devices are in high demand. However, a very limited number of blue OLEDs achieving high stability and color purity have been reported. Herein, three new sky‐blue emitters, 1,4,5‐triphenyl‐2‐(4‐(1,2,2‐triphenylvinyl)phenyl)‐1H‐imidazole (TPEI), 1‐(4‐methoxyphenyl)‐4,5‐diphenyl‐2‐(4‐(1,2,2‐triphenylvinyl)phenyl)‐1H‐imidazole (TPEMeOPhI) and 1‐phenyl‐2,4,5‐tris(4‐(1,2,2‐triphenylvinyl)phenyl)‐1H‐imidazole (3TPEI), with a combination of imidazole and tetraphenylethene groups, have been developed. High photoluminescence quantum yields are obtained for these materials. All derivatives have demonstrated aggregation‐induced emission (AIE) behavior, excellent thermal stability with high decomposition and glass transition temperatures. Non‐doped sky‐blue OLEDs with simple structure have been fabricated employing these materials as emitters and realized high efficiencies of 2.41 % (4.92 cd A⁻¹, 2.70 lm W⁻¹), 2.16 (4.33 cd A⁻¹, 2.59 lm W⁻¹) and 3.13 % (6.97 cd A⁻¹, 4.74 lm W⁻¹) for TPEI, TPEMeOPhI and 3TPEI, with small efficiency roll‐off. These are among excellent results for molecules constructed from the combination of imidazole and TPE reported so far. The high performance of a 3TPEI‐based device shows the promising potential of the combination of imidazole and AIEgen for synthesizing efficient electroluminescent materials for OLED devices.