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Zhao P.,Tianjin University of Technology | Shen J.,Tianjin University of Technology | Zhang H.,Tianjin Entry Exit Inspection and Quarantine Bureau
Materials Science Forum | Year: 2016

P91 heat-resistant steel is widely used in the high temperature of piping components of thermal power plants and nuclear power plants. In these conditions, the typical failure of P91 is mainly caused by creep at low stress. In this investigation the short-term creep behavior in P91 at low stress was investigated by helicoid spring creep test due to its high strain-sensitivity. The helicoid spring creep was based on the assumption of pure torsion. The mechanics field was firstly studied by ANSYS finite-element simulation to find the establishing conditions of pure torsion. Secondly, the creep properties of P91 were studied under the conditions of the temperatures of 0.38Tm

Fan M.,Jiangnan University | Zhang P.,Jiangnan University | Zhang Y.,Tianjin Entry Exit Inspection and Quarantine Bureau
Chemical Engineering Communications | Year: 2011

The catalytic synthesis of dipropyl carbonate (DPC) from transesterification of dimethyl carbonate and propyl alcohol over NaY zeolite-supported potassium salt catalysts was investigated at atmospheric pressure. K2CO3/NaY and KOH/NaY catalysts exhibited better catalytic activity than other potassium salt catalysts. From infrared resonance (IR), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), it could be concluded that K2CO3/NaY and KOH/NaY catalysts showed preferable order degree of zeolite structure, which was associated with higher dispersal of the active species K2O and extraction for part of the non-framework silicon and aluminum of the system after alkali treatment. And the partial extraction of the non-framework silicon and aluminum allowed the reactants and the products to pass through the pore of the catalysts easily and facilitated catalytic performance for DPC synthesis. © Taylor & Francis Group, LLC.

Wang G.-X.,Hunan Institute of Science and Technology | Lu M.,Jingdezhen Ceramic Institute | Li J.,Tianjin Entry Exit Inspection and Quarantine Bureau | Liu L.-C.,Hunan Institute of Science and Technology | And 3 more authors.
Iranian Polymer Journal (English Edition) | Year: 2013

Random copolymers of P(MMA-co-styrene) were synthesized via single electron transfer-living radical polymerization (SET LRP) at 25 C in N,N-dimethylformamide (DMF) and benzene using CCl4 as initiator and Fe(0) wire/N,N,N′,N′-tetramethyl-1,2-ethanediamine (TMEDA)/hydrazine (NH2NH2) complexes as catalyst in the presence of air. Fe(0) wire-mediated single electron transfer-living radical copolymerization of MMA and styrene represented a robust and versatile technique to synthesize the well-defined copolymers. The copolymerization rate was faster in DMF than in benzene, as determined by the apparent rate constants. The results showed that the copolymerization followed first-order kinetics model in the presence of polar DMF and non-polar benzene. The molecular weights increased linearly with the increase of monomer conversion with a narrow polydispersity index when the conversion was beyond 25 %. The polarity and the quantity of solvent had significant effects on the polymerization, and the apparent rate constants were 1.28 × 10-4, 1.21 × 10-4, and 9.23 × 10-5 s-1 in the order of DMF amount, 5, 10, and 15 mL. The conversion increased from 29.3 to 48.5 % and the polydispersity index (PDI) changed from 1.24 to 1.21 with [CCl4]0/[TMEDA]0 molar ratio changing from 1:0.5 to 1:5. The chain extension experiment demonstrated that the copolymerization exhibited a living characteristic. © 2012 The Author(s).

Wang G.-X.,Hunan Institute of Science and Technology | Lu M.,Jingdezhen Ceramic Institute | Hou Z.-H.,Hunan Institute of Science and Technology | Li J.,Tianjin Entry Exit Inspection and Quarantine Bureau | And 2 more authors.
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2013

In this work, Fe(0)-mediated single electron-living radical copolymerization of styrene (St) and acrylamide (AM) was investigated at ambient temperature in N,N-dimethylformamide using carbon tetrachloride as initiator and tetramethylethylenediamine as ligand. Kinetic studies showed that the copolymerization followed the first-order kinetics model. The resulting copolymers of St and AM possessed predetermined molecular weights and narrow molecular weight distribution, which agreed with the character of controlled/living polymerization. On the basis of Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (NMR), the monomer reactivity ratios were calculated. The amount of ligand played an important role in copolymerization. The obtained polymer was characterized by FTIR, 1H NMR, 13C NMR, and gel permeation chromatography. The living characteristics were demonstrated by chain extension experiment. © 2013 Wiley Periodicals, Inc.

Cui J.,Tianjin University | Xiao Y.-B.,Tianjin Entry Exit Inspection and Quarantine Bureau | Dai L.,Tianjin University | Zhao X.-H.,Tianjin University | Wang Y.,Tianjin University
Food Analytical Methods | Year: 2013

Concerning the residual organoarsenical feed additives, an effective method has been developed for the separation and determination of organoarsenic species including p-arsanilic acid (ASA), nitarsone (NIT) and roxarsone (ROX) in the food of animal tissue origin by high-performance liquid chromatography coupled to ultraviolet oxidation hydride generation atomic fluorescence spectrometry using a C18 column with 50 mM KH2PO4, 0.1 % v/v trifluoroacetic acid at pH 2.43 as the mobile phase. Accelerated solvent extraction (ASE) as an effective sample preparation method was used to deal with animal meat to extract organoarsenic species. The ASE conditions, including extraction solvent, temperature, static extraction time, flush volume and cycle time, were investigated in terms of extraction yield and species stability. In this paper, aimed to separate these species efficiently, the conditions of the mobile phase and HG system were also investigated. The methodology developed allows us limits of detection and quantification of 0.24, 0.74, 0.41 and 0.72, 2.24, 1.24 ng mL-1 for ASA, NIT and ROX, respectively. This method was used to separate and determine three organoarsenic species in porcine and chicken liver samples that were purchased at a supermarket in China. At the optimized conditions, the ranges of concentrations of the three arsenic species were found to be varied from 3 to 9 ng mL-1. The results of recovery rates and RSDs, which were higher than 94 % and lower than 5 %, respectively, approved it to be a convenient, fast and efficient method for the determination of organoarsenic species in animal tissue. © 2012 Springer Science+Business Media New York.

Liao F.,Nankai University | Wang L.,Beijing Entry Exit Inspection and Quarantine Bureau | Wu S.,ShenYang Agricultural University | Li Y.-P.,ShenYang Agricultural University | And 5 more authors.
International Journal of Biological Sciences | Year: 2010

The complete mitochondrial genome (mitogenome) of the fall webworm, Hyphantria cunea (Lepidoptera: Arctiidae) was determined. The genome is a circular molecule 15 481 bp long. It presents a typical gene organization and order for completely sequenced lepidopteran mitogenomes, but differs from the insect ancestral type for the placement of tRNAMet. The nucleotide composition of the genome is also highly A + T biased, accounting for 80.38%, with a slightly positive AT skewness (0.010), indicating the occurrence of more As than Ts, as found in the Noctuoidea species. All protein-coding genes (PCGs) are initiated by ATN codons, except for COI, which is tentatively designated by the CGA codon as observed in other lepidopterans. Four of 13 PCGs harbor the incomplete termination codon, T or TA. All tRNAs have a typical clover-leaf structure of mitochondrial tRNAs, except for tRNASer(AGN), the DHU arm of which could not form a stable stem-loop structure. The intergenic spacer sequence between tRNASer(AGN) and ND1 also contains the ATACTAA motif, which is conserved across the Lepidoptera order. The H. cunea A+T-rich region of 357 bp is comprised of non-repetitive sequences, but harbors several features common to the Lepidoptera insects, including the motif ATAGA followed by an 18 bp poly-T stretch, a microsatellite-like (AT)8 element preceded by the ATTTA motif, an 11 bp poly-A present immediately upstream tRNAMet. The phylogenetic analyses support the view that the H. cunea is closerly related to the Lymantria dispar than Ochrogaster lunifer, and support the hypothesis that Noctuoidea (H. cunea, L. dispar, and O. lunifer) and Geometroidea (Phthonandria atrilineata) are monophyletic. However, in the phylogenetic trees based on mitogenome sequences among the lepidopteran superfamilies, Papillonoidea (Artogeia melete, Acraea issoria, and Coreana raphaelis) joined basally within the monophyly of Lepidoptera, which is different to the traditional classification. © Ivyspring International Publisher.

Li X.,Tianjin Entry Exit Inspection and Quarantine Bureau | Jia X.,Tianjin Entry Exit Inspection and Quarantine Bureau | Li J.,Tianjin Entry Exit Inspection and Quarantine Bureau
Acta Crystallographica Section E: Structure Reports Online | Year: 2013

The title compound, C12H12BrNO4S 2, was obtained by the Sandmeyer reaction from ethyl 3-amino-4-cyano-5-[(2-ethoxy-2-oxoethyl)sulfanyl]thiophene-2-carboxylate. The dihedral angle between the thiophene ring and linked CO2 ester group is 2.0 (5)°. © Li et al. 2013.

Xiao Y.-B.,Tianjin Entry Exit Inspection and Quarantine Bureau | Zhang M.,Tianjin Entry Exit Inspection and Quarantine Bureau | Wen H.-W.,Tianjin Entry Exit Inspection and Quarantine Bureau
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2014

A method for simultaneous determination of arsanilic, nitarsone and roxarsone (ROX) residues in foods of animal origin was developed by accelerated solvent extraction-liquid chromatography-atomic fluorescence spectrometry (ASE-LC-AFS). The ultrasound centrifugation extraction and accelerated solvent extraction were compared, and the accelerated solvent extraction conditions, namely the proportion of the extraction solvent, the extraction temperature, extraction time and extraction times, were optimized. The operating conditions of LC-AFS and the mobile phase were optimized. Under the optimal conditions, the calibration curves for ASA, NIT and ROX were linear over the concentration range of 0~2.0 mg·L-1 and their correlation coefficients were 0.9992~0.9998. The detection limits of ASA, NIT and ROX were 2.4, 7.4 and 4.1 μg·L-1 respectively. The average recoveries of ASA, NIT and ROX from two samples spiked at three levels of 0.5, 2, 5 mg·kg-1 were in the ranges of 87.1%~93.2%, 85.2%~93.9%, and 84.2%~93.7% with RSDs of 1.4%~4.6%, 1.2%~4.2%, and 1.1%~4.5%, respectively. This method possesses the merits of convenience and good repeatability, and is a feasible method for analysis of ASA, NIT and ROX in foods of animal origin.

Yulong Z.,Nankai University | Xia Z.,Tianjin Entry Exit Inspection and Quarantine Bureau | Hongwei Z.,Tianjin Entry Exit Inspection and Quarantine Bureau | Wei L.,Tianjin Entry Exit Inspection and Quarantine Bureau | And 2 more authors.
Molecular and Cellular Probes | Year: 2010

Enterobacter sakazakii is a widespread and life-threatening bacterium especially in polluted powdered infant milk formula. Several methods have been developed for detection of E. sakazakii such as physiological and biochemical methods, PCR and loop-mediated isothermal amplification. However, these procedures were disadvantages due to a long assay time, low sensitivity or the use of toxic reagents. Our method of cross-priming amplification (CPA) under isothermal conditions combined with immuno-blotting analysis made the whole detection procedure more sensitivity and lower time-consuming. A set of specific displacement primers, cross primers and testing primers were designed based on six specific sequences in E. sakazakii 16S-23S rDNA internal transcribed spacer. Under isothermal condition at 63 °C for 60 min, the specific amplification and hybridization steps were processed simultaneously. The specificity of the CPA was tested in panel of 54 different bacterial strains and 236 milk powder products. Two red signal lines were developed on the BioHelix Express strip in all of positive E. sakazakii strains, and only one signal line was demonstrated by non- E. sakazakii bacterial strains. The limit of decetion of CPA was 6.3 ± 2.7277 fg for the genomic DNA, 88 ± 8.7892 cfu/ml for pure bacterial culture, and 3.2 ± 2.0569 cfu per 100 g milk powder with pre-enrichment. The current study demonstrated that the assay method of CPA combined with immuno-blotting analysis was a specific and sensitive detection for the rapid detection of E. sakazakii. © 2010 Elsevier Ltd.

Wang S.,Tianjin University of Science and Technology | Shi J.,Tianjin University of Science and Technology | Zheng L.,Tianjin Entry Exit Inspection and Quarantine Bureau
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2012

CNTs/PLA composites were prepared by solution blending method in the presence of pristine carbon nanotubes(MWCNTs)and carboxylated carbon nanotubes(MWCNTCOOH). The dispersity of CNTs, crystallization morphology, electric conductivity and degradation were studied. The results show that MWCNTCOOH are dispersed more homogeneously in PLA than the pristine MWCNTs by SEM. POM(Polarizing Optical Microscope) results shows that the MWCNTs act as effective nucleating agents and decrease the crystal size. With the addition of a little MWCNTCOOH, the volume resistivity of the nanocomposite decreases by 7 orders of magnitude, and the degradation also increases by MWCNTCOOH.

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