The Infrared Characterization and Mechanism of Oxygen Adsorption in Coal

The remarkable differences between the infrared spectra of oxygen adsorption and nitrogen desorption in coal have been experimentally and theoretically investigated. Density functional theory calculations were performed to better explain the mechanism of oxygen adsorption using six different molecular models of coal. In addition, the remarkable differences of infrared spectra between oxygen adsorption and nitrogen desorption was defined as the index V, which was used to classify the spontaneous combustion tendency of coal. The experimental data indicated that the spectra in the 4000–2000 cm^?1 and 1250–1050 cm^?1 regions exhibited significant changes. These results suggest that the mechanism of oxygen adsorption is the alteration and transfer of charge density around the activated sites, which leads to the observed changes of the infrared spectra. The V, which is related to the alteration of spectral intensity, is found to decrease with the increase of adiabatic oxidation time and the relative spontaneous combustion period of coal. This observation solidifies the connection between sample spectral intensity and oxygen chemisorption. These data suggest that the hydroxy in hydroxy and carboxyl groups on the surface of coal particles is the site of oxygen chemisorption, and the V can be used to rapidly and accurately categorize the spontaneous combustion tendency of coal.     

Far-field characteristics of coherently combined beams emitted from arrays on multiple polygons

By using Fourier Optics, the general analytical expression of intensity distribution for the coherently combined beams positioned on the X-Y plane, which is applicable to both Gaussian and non-Gaussian beams, can be derived. Considering the fact that in many cases the array configuration can be regarded as composed of several regular polygons with a common center, an explicit analytical expression of the far-field intensity distribution for these cases has been derived. As an example, the above expression has been applied to study a 19 emitter array. Studies have also been done on the dark fringes of the far-field pattern for the specific emitters, whose numbers are 2 and 4, respectively.     

Novel Annonaceous acetogenins from Graviola (Annona muricata) fruits with strong anti-proliferative activity

Five bioactive Annonaceous acetogenins, including three new compounds, annonamuricins A (1), B (2), and C (3), one registered but no spectral data reported compounds, annonamuricin D (4), and one known compound annonacin (5) were isolated from Graviola fruit (Annona muricata) and further determined through bioassay-guided fractionation. All five compounds are C35 Anonnonaceous acetogenins with a mono-tetrahydrofuran ring and four hydroxyls. Their structures were elucidated using spectral methods as well as chemical modification after isolation via chromatographic techniques and HPLC purification. These acetogenins demonstrated potent anti-proliferative activities against human prostate cancer PC-3 cells.     

Global existence of shock front solutions in 1-dimensional piston problem in the relativistic Euler equations

The paper studies the 1-D piston problem of the relativistic Euler equations when the speed of the piston is a perturbation of a constant. A sequence of approximate solutions constructed by a modified Glimm scheme is proved to be convergent to the weak solution (which includes a strong leading shock) to the piston problem. In particular, we give the precise estimates on the reflection of the perturbed waves on the piston and the leading shock. The paper is supported by the National Natural Science Foundation of China (Grant 10626034) and the Special Research Fund for Selecting Excellent Young Teachers of the Universities in Shanghai.     

Simultaneous analysis of polygala acid,senegenin and 3,6′‐disinapoylsucrose in rat plasma by liquid chromatography–tandem mass spectrometry: application to a pharmacokinetic study after oral administration

A rapid and specific LC‐MS/MS method has been developed for the simultaneous analysis of polygala acid, senegenin and 3,6′‐disinapoylsucrose (DSS) in rat plasma. The method was applied to the pharmacokinetics studies of polygala acid, senegenin and DSS. The analysis was carried out on an Agilent Eclipse plus C₁₈ reversed‐phase column (100 × 4.6 mm, 3.5 µm) by gradient elution with methanol and ammonia (0.01%, v/v). The flow rate was 0.4 mL/min. All analytes including internal standard (IS) were monitored by selected reaction monitoring with an electrospray ionization source. Linear responses were obtained for polygala acid and DSS ranging from 2.5 to 2000 ng/mL, and senegenin ranging from 5 to 2000 ng/mL. The intra‐ and inter‐day precisions (relative standard deviation) were <11.34 and 8.99%. The extraction recovery ranged from 70.89 ± 4.60 to 88.49 ± 3.26%, and that for the IS was 77.23 ± 3.68%. Stability studies showed that polygala acid, senegenin and DSS are stable during the preparation and analytical process. The validated method was successfully used to determine the concentration–time profiles of polygala acid, senegenin and DSS. Copyright © 2013 John Wiley & Sons, Ltd.     

Crystal and Molecular Structure of Copper(Ⅰ) Complex 〔Cu(PPh_3)_2(NO_3)〕

1　 INTRODUCTIONCopper( ) displays a wide diversity in its structural chemistry,the copper co-ordination number ranging from two to four.Procedures to synthesize copper( )complexes are of greatinterestbecause of the diversity of products resulting from al-mostthe same methodology.Ithaslong been accepted thatcopper( ) complexesarediamagnetic and provide no optical absorption bands( no d- d transition isencountered) for a copper( ) ion with a d10 configuration and no electron spin reso-n…     

Facile synthesis of magnetic microcapsules by synchronous formation of magnetite nanoparticles

Magnetite/poly (lactic acid) (PLA) composite microcapsules with controllable composition and magnetic property were synthesized by a facile interfacial coprecipitation joint double emulsion–solvent evaporation process. In this method, the interfacial coprecipitation was performed at the water-in-oil (W₁/O) interface and the generated Fe₃O₄ nanoparticles were incorporated into PLA microcapsules simultaneously. The magnetite content of the resultant composite microcapsules can be controlled as high as 38 wt.%. This novel method not only simplifies the fabrication process but also improves the magnetic property of composite microcapsules.     

A mixed‐valence complex of cobalt based on 3‐methoxysalicylaldoxime

A new tetranuclear mixed‐valence cobalt complex, namely di‐μ₂‐azido‐diazidodiethanolbis{μ₂‐2‐[(hydroxyimino)methyl]‐6‐methoxyphenolato}bis{μ₃‐6‐methoxy‐2‐[(oxidoimino)methyl]phenolato}dicobalt(II)dicobalt(III) ethanol disolvate, [Co^II₂Co^III₂(C₈H₇NO₃)₂(C₈H₈NO₃)₂(N₃)₄(C₂H₅OH)₂]·2C₂H₅OH, has been synthesized by the reaction of Co(OAc)₂·4H₂O (OAc is acetate) with 3‐methoxysalicylaldoxime (H₂mosao) in an ethanol solution. In the complex, the four Co cations all display distorted octahedral coordination environments and they are bridged by two κ²,κ¹,κ¹;μ₃‐mosao²⁻ ligands, two κ²,κ²;μ₂‐Hmosao⁻ ligands and two μ₂‐N₃⁻ anions to form a tetranuclear [Co₄N₄O₄] cluster. Adjacent clusters are connected through weak C—H...N and C—H...O interactions, resulting in a two‐dimensional supramolecular network parallel to the ac plane. The magnetic properties of the complex have also been studied.