Effective optical path length investigation for cubic diffuse cavity as gas absorption cell

A simple cubic-shaped cavity with a high-diffuse-reflectivity inner coating as a novel gas detection cell was developed. The effective optical path length (EOPL) was evaluated by comparing the oxygen absorption signal in the cavity and in air based on tunable diode laser absorption spectroscopy. The law for a spherical cavity was applied and modified to a cubic cavity as a function of reflectivity ρ, port fraction f, and the side length. Single-pass average path length of the cubic cavity was 0.723(7) times the side length. EOPL can be modified conveniently by adjusting the parameters of the cavity.     

Hierarchical nanostructured composite cathode with carbon nanotubes as conductive scaffold for lithium-sulfur batteries

Carbon nanotubes (CNTs) are excellent scaffolds for advanced electrode materials, resulting from their intrinsic sp2 carbon hybridization, interconnected electron pathway, large aspect ratio, hierarchical porous structures, and low cost at a large-scale production. How to make full utilization of the mass produced CNTs as building blocks for nanocomposite electrodes is not well understood yet. Herein, a composite cathode containing commercial agglomerated multi-walled CNTs and S for Li-S battery was fabricated by a facile melt-diffusion strategy. The hierarchical CNT@S coaxial nanocables exhibited a discharging capacity of 1020 and 740 mAh g-1 at 0.5 and 2.0 C, respectively. A rapid capacity decay of 0.7% per cycle at the initial 10 cycles and a slow decay rate of 0.14% per cycle for the later 140 cycles were detected. Such hierarchical agglomerated CNT@S cathodes show advantages in easy fabrication, environmentally benign, low cost, excellent scalability, and good Li ion storage performance, which are extraordinary composites for high performance Li-S battery.     

一种CO2的矿化封存新方法

针对目前CO2矿化封存的研究现状,提出了一种新的CO2矿化封存方法:利用CO2和NH3反应生成三聚氰酸固体,并考察了温度、压力、反应物配比及有无催化剂对三聚氰酸收率的影响。当反应条件为在250℃,22MPa,NH3与CO2反应配比为1∶1.4,反应8h时,最高收率可达到68.3%。此项技术能够与现在工业成熟的富氧燃烧技术联用,实现对CO2的永久性封存,具有经济效益。     

Synthesis and characterization of fluorine-containing cholesteric liquid crystalline polysiloxanes bearing trifluoromethyl-substituted mesogens

A series of side-chain liquid crystal (LC) polysiloxanes were synthesised with Poly(methylhydrogeno)siloxane, 4?-(undec-10-enoyloxy) biphenyl – 4 – yl 4- (trifluoromethyl) benzoate (M_th) and a chiral nematic (N*) LC monomer 1-allyl 10-(cholesteryl)-decanedioate (M_ch). The chemical structures and LC properties of the monomers and polymers were characterised by FTIR, ¹H-NMR, differential scanning calorimetry, thermogravimetric analysis, POM and X-ray diffractometer. M_ch is monotropic N* LC. The homopolymer derived from monomer M_ch is enantiotropic N* LC. Monomer M_th is a smectic A liquid crystal. The copolymers derived from M_ch and M_th are N* LCs. The temperatures at which 5% weight loss occurred are greater than 300°C for all the fluoro-containing polymers, and the residue weights of the samples at 600°C increased slightly as the content of trifluoromethyl mesogens increased in the polymers. The glass transition temperatures of the polymers increased as trifluoromethyl mesogens increased, too. The N*–I phase transition temperatures show a negative deviate from ideal or linear behaviour. The values of the enthalpy changes for the cholesteryl containing polymers are rather low and this is attributed to the biaxiality of cholesteryl moiety which tends to reduce the change in the orientational order at the N*–I transition. Compared to the monomers, the polymers show wider mesophase region.     

Nano n‐propylsulfonated γ‐Al2O3: a new,efficient and reusable catalyst for synthesis of spiro[indoline‐3,4‐pyrazolo[3,4‐e][1,4]thiazepine]diones in aqueous media

Nano n‐propylsulfonated γ‐Al₂O₃ is easily prepared by the reaction of nano γ‐Al₂O₃ with 1,3‐propanesultone. This reagent can be used as an efficient catalyst for the synthesis of spiro [indoline‐3,4‐pyrazolo[3,4‐e][1,4]thiazepine]diones in aqueous media. This new method consistently has the advantages of excellent yields and short reaction times. Further, the catalyst can be reused and recovered several times. Copyright © 2013 John Wiley & Sons, Ltd.     

Profiling and identification of the absorbed constituents and metabolites of schisandra lignans by ultra‐performance liquid chromatography coupled to mass spectrometry

Schisandra chinensis Baill grows wild in Russia, China, Korea and Japan, and its fruit has been found to be effective in amnesia and insomnia. It is enriched in schisandra lignans (SL) that are major components responsible for therapeutic action. However, there are no reports on the biotransformation analysis of SL. An ultra‐performance liquid chromatography/electrospray‐ionization high‐definition mass spectrometry (UPLC‐Q‐TOF‐HDMS) method was developed to investigate the metabolism of SL in vivo. MS was performed on a Waters Micromass high‐definition system with an electrospray ionization source in positive ion mode and automated MetaboLynx software analysis with excellent MS accuracy and enhanced MS data acquisition. An improved mass defect filter (MDF) method employing both drug and core structure filter templates was applied to the processing of UPLC‐Q‐TOF‐HDMS data for the detection and structural characterization of metabolites. In this study, 30 metabolites were detected and identified in vivo, and demethylation and hydroxylation were confirmed as the primacy metabolic pathway for SL in rat plasma. In conclusion, the presently developed methodology was suitable for biotransformation research of SL and will find wide use in metabolic studies for other herbal medicines. Copyright © 2013 John Wiley & Sons, Ltd.