Evaluation of the factors affecting extraction of organic compounds based on the acid-induced phase cloud point approach

On the basis of a better analytical exploitation of acid-induced cloud point approach, a systematic study on the phase behaviour of acid aqueous solutions of anionic surfactants and factors affecting anionic surfactant-mediated extractions was performed. The anionic surfactants investigated were alkylsulphonates (ASS) with alkylchain lengths comprised between 8 and 16 carbon atoms. The critical hydrochloric acid concentration (minimal acid concentration required to separation in two liquid phases) was found to increase as alkylchain length of the anionic surfactant increased from 10 to 14. Non-acid-induced liquid-liquid phase separation was observed for sodium octanesulphonate (SOS) or sodium hexadecyl sulphonate (SHS) in the hydrochloric concentration range 0-10 M. Acid aqueous solutions of sodium decylsulphonate (SDeS) and sodium dodecylsulphonate (SDoS) separated into two liquid phases at temperatures ranging between 10 and 80 °C, while temperatures >35 °C were required for sodium tetradecylsulphonate. The influence on extraction efficiency and concentrating ability of experimental variables such as hydrophobicity and concentration of surfactant, nature and concentration of analyte, hydrochloric acid concentration, time and temperature of extraction and time of equilibration and centrifugation was examined. Advantages provided by anionic surfactant-mediated extractions over the use of non-ionic surfactants (cloud point extractions) are discussed.     

Multiscale simulation of pollution gases adsorption in porous organic cage CC3

A general multiscale simulation procedure is proposed to accurately predict the uptakes of pollution gases such as CO₂, SO₂, H₂S, and CO in one of the most investigated porous organic cages CC3 by using a sophisticated force field vdW3 fitted by double hybrid functional (B2PLYP) with a dispersion correction (D3) separately for gas–gas and CC3‐gas interactions. The fitted vdW3 was used in grand canonical Monte Carlo simulations. Good comparison with the coupled cluster single and double excitation and the perturbative triples (CCSD(T))/complete basis set (CBS) limit interaction energies make the B2PLYP‐D3 results reliable for our purpose. The good agreement of simulated CO₂ loading with experimental one and the low deviation in the fitting procedure for H₂S and CO make our approach available in predicting gases in novel porous materials. © 2013 Wiley Periodicals, Inc.     

Gas chromatography-mass spectrometry as a tool for estimating odour concentrations of biofilter effluents at aerobic composting and rendering plants

The relationship between chemical concentrations (gas chromatography–mass spectrometry analysis) and odour concentrations (olfactometry) was studied for biofilter emissions from four aerobic vegetable, fruit and garden waste (VFG) composting plants and one animal rendering plant. For the VFG composting plants, the study revealed a good linear relationship of the odour concentration with the total volatile organic compounds (VOC) concentration (R²=0.97, n=16) as well as with the concentration of esters and ketones (R²=0.9, n=19). For biofilter emissions of the animal rendering plant, the total VOC concentration was a poor estimator for odour concentration. However, for this type of odour, concentrations of organic sulphur containing compounds correlated well with odour concentrations (R²=0.94, n=8). The results of the study also showed that the relationship between chemical and odour concentrations is specific for each type of odour and cannot be generalized.     

Solid-State 17O NMR studies of organic and biological molecules: Recent advances and future directions

This Trends article highlights the recent advances published between 2012 and 2015 in solid-state ¹⁷O NMR for organic and biological molecules. New developments in the following areas are described: (1) new oxygen-containing functional groups, (2) metal organic frameworks, (3) pharmaceuticals, (4) probing molecular motion in organic solids, (5) dynamic nuclear polarization, and (6) paramagnetic coordination compounds. For each of these areas, the author offers his personal views on important problems to be solved and possible future directions.     

非晶CS/RB纳米薄膜的荧光性质

采用低真空物理气相沉积法制备单组份氰基对称二苯代乙烯(CS)纳米薄膜和罗丹明B(RB)纳米薄膜以及CS/RB叠层纳米薄膜。使用荧光分光光度计、X射线衍射仪(XRD)和扫描电子显微镜(SEM)表征薄膜样品的荧光性质、结构和表面形貌。与粉末晶态样品相比,薄膜样品的荧光发射峰数量变多,发射波长范围拓宽到120 nm。有机小分子的非晶聚集态和纳米叠层结构的的纳米效应导致了样品的荧光性质的变化。     

Unconventional Coding Technique Applied to Multi-Level Polarization Modulation

A new technique is proposed to improve information confidentiality in optical-fiber communications without bandwidth consumption. A pseudorandom vectorial sequence was generated by a dynamic system algorithm and used to codify a multi-level polarization modulation based on the Stokes vector. Optical-fiber birefringence, usually considered as a disturbance, was exploited to obfuscate the signal transmission. At the receiver end, the same pseudorandom sequence was generated and used to decode the multi-level polarization modulated signal. The proposed scheme, working at the physical layer, provides strong information security without introducing complex processing and thus latency.     

Enhanced luminance of white organic light-emitting diode with yellow nanophosphors-embedded blue polymer emitting layer

White organic light-emitting device was achieved through an incorporation of yellow YAG nanophosphors into blue polyfluorene emitting layer: electrode/YAG@polyfluorene/hole-transport/injection layers/ITO glass. The brightness of the proposed device (230 cd/m² at 30 V) was enhanced by a factor of about two in comparison with that of phosphor-free reference device. It is attributed to the increased local electric field caused by bumps of nanophophors on the emitting layer. With increase of voltage, the blue-green emission decreased whereas the yellow emission increased. It is due to the effective energy transfer from the blue-green to the yellow bands.     

激子位置不同微腔有机电致发光器件性能模拟

微腔有机电致发光器件(MOLED)的发光特性直接与微腔的结构相关,可以根据微腔器件的相关计算公式,运用传输矩阵法对MOLED进行模拟设计。本文对微腔总长度L=λ/2(λ:中心波长)不变情况下,激子在微腔内不同位置复合发光的电致发光(EL)光谱性能进行模拟并比较。结果表明:发光谱的峰值都在所设计的中心波长520nm处,半峰全宽(FWHM)都是17nm,激子处在微腔的中心区域时,峰值强度和积分强度都是最大,这是因为激子此时位于腔内电场的最大值处,偏离此处的两侧逐渐变小。以上结果表明:要制作出高效率的MOLED,必须使激子处于微腔内的最佳位置处。