Studies on lignan constituents from Schisandra chinensis (Turcz.) Baill. fruits using high-performance liquid chromatography/electrospray ionization multiple-stage tandem mass spectrometry

A reversed-phase high-performance liquid chromatography-diode array detector-electrospray ionization multiple-stage tandem mass spectrometry (RP-HPLC-DAD-ESl-MSn) method has been developed for the detection and analysis of lignan constituents in the methanol extract from the fruits of Schisandra chinensis (Turcz.) Baill. RP-HPLC-DAD-ESI-MSn and electrospray ionization Fourier transform ion cyclotron resonance multiple-stage tandem mass spectrometry (ESI-FT-TCR-MSn) have been applied to investigate the characteristic product ions of four lignan reference compounds. Then, the logical fragmentation pathways of the lignans have been proposed. By comparing the retention time (t(R)) of HPLC, the ESI-MSn data and the structures of analyzed compounds with the data of reference compounds and in the literature, 11 peaks in HPLC have been unambiguously identified and another 5 peaks have been tentatively identified or deduced. Also, in the present paper, the extracted ion chromatograms (EIC) have been used to analyze the lignan isomers. The experimental results demonstrate that RP-HPLC-DAD-ESI-MSn is a specific and useful method for the identification of the lignan constituents and their isomers.

Thickness-dependent molecular chain and lamellar crystal orientation in ultrathin poly(di-n-hexylsilane) films

The molecular chain and lamellar crystal orientation in ultrathin films (thickness < 100 nm) of poly(di-n-hexylsilane) (PDHS) on silicon wafer substrates have been investigated by using transmission electronic microscopy, wide-angle X-ray diffraction, atomic force microscopy, and UV absorption spectroscopy. PDHS showed a film thickness-dependent molecular chain and lamellar crystal orientation. Lamellar crystals grew preferentially in flat-on orientation in the monolayer ultrathin films of PDHS, i.e., the silicon backbones were oriented along the surface-normal direction. By contrast, the orientation of lamellar crystals was preferentially edge-on in ultrathin films thicker than ca. 13 nm, i.e., the silicon backbones were oriented parallel to the substrate surface. We interpret the different orientations of molecular chain and lamellar crystal as due to the reduction of the entropy of the polymer chain near the substrate surface and the particularity of the crystallographic (001) plane of flat-on lamellae, respectively. A remarkable influence of the orientations of the silicon backbone on the UV absorption of these PDHS ultrathin films was observed due to the one-dimensional nature of sigma-electrons delocalized along the silicon backbone.

4-(2-fluorobenzylideneamino)-3-(1,2,4-triazol-4-ylmethyl)-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C12H10FN7S, the dihedral angles made by the plane of the thione-substituted triazole ring with the planes of the other triazole ring and the benzene ring are 74.55 (2) and 11.50 (3)degrees, respectively. The structure shows a number of N - H center dot center dot center dot N intermolecular hydrogen-bonding interactions, and weak C - H center dot center dot center dot S intra- and intermolecular interactions.

4-[3-(1,2,4-Triazol-1-yl)propionyl]phenyl 4-fluorobenzoate

In the title compound, C-18(14)3(3)H(FN)O, the dihedral angles made by the triazole ring with the plane of the central benzene ring and the p-fluorophenylcarbonyl group are 82.09 ( 2) and 82.05 (2), respectively. There are weak C-H...O intra- and intermolecular interactions in the crystal structure, which contribute to the stability.

2-(Benzotriazol-1-yl)-2-(alpha-hydroxybenzyl)-N-phenylthioacrylamide

In the title compound, C21H16N4OS, the dihedral angles between the planes of the benzotriazole and N-phenyl rings and the plane of the atoms that link these two rings are 79.56 (6) and 59.02 (5) degrees, respectively, while that between the two benzene rings is 64.12 (6) degrees. There are some inter- and intramolecular interactions in the crystal structure.

4-(4-chlorobenzylideneamino)-3-(1H-1,2,4-triazol-1-ylmethyl)-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C12H10ClN7S, the dihedral angles made by the plane of the thione-substituted triazole ring with the planes of the other triazole ring and the benzene ring are 73.57 (3) and 46.65 (2)degrees, respectively. Inter-and intramolcular hydrogen bonds and pi-pi stacking interactions stabilize the structure.

5-[(1H-1,2,4-yriazol-1-yl)methyl]-4-(4-fluorobenzylideneamino)-2H-1,2,4-triazole-3(4H)-thione

In the title compound, C12H10FN7S, the dihedral angles made by the plane of the thione-substituted triazole ring with the planes of the other triazole ring and the benzene ring are 71.94 (3) and 40.10 (2)degrees, respectively. Inter- and intramolecular hydrogen-bond and pi-pi stacking interactions stabilize the structure.

智能化工程机械发展战略研究

The intelligent level of construction machinery abroad is described in the article. In association with automation level of domestic construction machinery, developing targets are pointed out. Some plans and schemes in national technical 863 projects are introduced, which may be of reference to domestic enterprises when making developing schedule for organization.