查看更多>>摘要：A novel chemiluminescence system for the determination of bismerthiazol is first described in this paper. It is based on the chemiluminescence reaction of bismerthiazol and Ce(Ⅳ) in nitric acid solution. The emis-sion intensity could be enhanced greatly by Rhodamine B. The chemiluminescence intensity was proportional to bis-merthiazol concentration over the range 30-1000 μg/L. The detection limit was 12 μg/L (3σ) and the relative standard deviation is 2.4% for 500 μg/L of bismerthiazol (n = 11). The proposed method was successfully applied to the determination of bismerthiazol in water and in rice. The recovery was 96.4%-104.1%.
查看更多>>摘要：Chlorosulfonyl-containing naphthol azo com-pounds were prepared by reaction of the corresponding sulfonate-containing naphthol azo dyes with thionyl chloride in the presence of a catalytic quantity of N,N-dimethylformamide and various solvents. The yields and reaction selectivity of chlorosulfonyl-containing naphthol azo compounds were discussed according to the prop-erties of solvents. It was demonstrated that high chemical selectivity and high yield were achieved by using benzene, toluene or thionyl chloride as solvent. Additionally, on account of unstable properties of sulfonyl chloride com-pounds in MS and 1H-NMR analyses, a new analytical method using stable sulfonamide is put forward to verify the chemical structures of the corresponding sulfonyl chloride compounds indirectly.
查看更多>>摘要：Amphiphilic comb-like polysiloxane (ACPS) containing polyether side chains was used as the modifica-tion reagent in the preparation of hydrophilic porous poly (vinylidene fluoride) (PVDF) membranes via a phase inversion process. The effects of ACPS on morphology, crystallinity, mechanical properties, reservation of ACPS in the phase inversion process, chemical structure, hydro-philicity and filterability performance of porous PVDF membranes were discussed. It was found that the addition of ACPS would result in the delayed demixing which yields "sponge-like" sublayers and longer crystallization time during the membrane formation process. It was revealed that O/F ratios of the bulk membrane were almost the same as those of the corresponding casting solutions which obviously indicated the high reservation of ACPS in the membrane formation process. The fact that the O/F ratios in the membrane surface layers were much higher than those in the bulk membrane proved the enrichment of ACPS on the surface. The filterability experiments and water contact angle testing proved the hydrophilicity of the blend membranes. Through a schem-atic model, the mechanism relating the membrane struc-ture and performance was interpreted. From the observed results, it can be concluded that ACPS acts as a potential candidate material for preparing PVDF membranes with extraordinary hydrophilicity and filterability.
查看更多>>摘要：A two-step swelling procedure was adopted to synthesize mono-dispersed and highly cross-linked poly (St-divinylbenzene) particles with PSt micro-spheres (1.80 μmin diameter). The PSt micro-spheres were prepared by a dispersion polymerization method and used as seeds. The effects of monomer concentration, ratio of ethanol to water, swelling reagents, crosslinking reagents, swelling temper-ature and agitation speed on particle size were investigated in detail. The morphologies and size distributions of these micro-spheres were examined by SEM and particle size analysis (PSA). The Tg of the micro-spheres was measured by DSC. The results indicate that the particles (6.20 μm in diameter) exhibit excellent mono dispersed property and high crosslinking degree when the concentration of the swelling reagent was 25%, the concentration of the cross-linking reagents was 23%, the swelling temperature was 30℃ and the stirring speed was 150 r/min.
查看更多>>摘要：In this paper, the crystallization behavior, ther-mal degradation properties, rheological behavior and the spinnability of poly(β-hydroxybutyrate-co-hydroxyvale-rate) (PHBV) fiber were studied. Experimental results indicated that the spherulite growth rate of PHBV was very slow and its size was very large. PHBV began to degrade above 170℃. The flowing curve indicated that the processing temperature and the residential time had important effects on PHBV melts. When the equipment of melting spinning was improved and processing conditions were strictly controlled, the mechanical properties of the PHBV filament can comply with the requirements of the American Pharmacopoeia.
查看更多>>摘要：β-tricalcium phosphate (β-TCP) is a key com-ponent of natural bone like hydroxyapatite. Pure and uni-formly nanosized β-tricalcium phosphate powders were synthesized using a sol-gel self-propagating combustion method by using citric acid as a reductant and using fuel and nitrate as the oxidant. The thermal decomposition of nitrate-citrate xero-gel was studied by thermogravimetric-differential thermal analysis (TG/DTA) and the process mechanism of self-propagating combustion were discussed. The resulting powders calcined at 1023, 1173 and 1273 K were characterized by Ca/P ratio analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmis-sion electron microscopy (TEM). It was found that the as-prepared powders were pure β-tricalcium phosphate having regular porous surface very similar to coral.
查看更多>>摘要：Magnetic polymer microspheres have been considered as a kind of new biopolymer materials with great advantages in bioseparation engineering and biome-dicine engineering because they have not only polymer functional groups but also magnetic characteristics. Styrene-acrylic acid copolymer (p(S-AA)) magnetic microspheres were synthesized by dispersion polymeriza-tion with Fe3O4 as core and p(S-AA) as shell. The micro-spheres were characterized by SEM, size analysis, molecular weight and solid content measurement. All of them indicate that the microspheres are small in size, nar-row in distribution, stable in chemistry and rich in func-tional groups on their surface.
查看更多>>摘要：ZnO nanorings were synthesized on a large scale by an easy solution-based method at 70℃ for 5 h using hexamethylenetramine (C6H12N4, HMT) and Zn ant poly(acrylamide-co-diallyldimethylammonium chlor-ide) (PAM-CTAC). The structure and morphology of the products were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The influence of experimental conditions such as concentra-tion of surfactant and reactants, reaction temperature on the structure and morphology of the products were inves-tigated. A probable formation mechanism of ZnO nanor-ings in the presence of surfactant PAM-CTAC was discussed. The results show that the products are wurtzite hexagonal ZnO nanorings with an inner diameter of 220 nm and a wall thickness of 70 nm. Reaction temper-ature and concentration of reactants influence the shape and size ofZnO nanorings but PAM-CTAC plays the key role in the formation of ZnO nanorings. Through adjust-ing the concentration of PAM-CTAC, controlled-syn-thesis of ZnO nanorings can be realized. A room temperature photoluminescence (PL) spectrum of ZnO obtained shows that the full width at half maximum (FWHM) of the UV emission (～7 nm) is much narrower than that of commercial ZnO bulk crystals (～18 nm). The narrow FWHM confirms the uniformity and narrow size distribution of the synthesized ZnO crystals.
查看更多>>摘要：Using 3-O-methyl-D-chiro-inositol as starting material, the title compound 5 was synthesized by con-densation of adenine and methanesulfonate 3. Additionally, compounds 8 and 9 were prepared through the opening of the epoxide ring in 7 by adenine. The key intermediate 7 was obtained in good yield via an epoxida-tion from mono-mesylate 6. The process of opening of epoxide ring appeared to be regioselective in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).
查看更多>>摘要：β-Mn2V2O7 microtubes with a length of 15-25 μm, 2.5-3.5μm external diameter, and～0.4μm wall thickness, as well as β-Mn2V2O7 hollow microsphereswith an average outer diameter of 2 μm, were successfully synthesized in a suitable molar ratio of NH4VO3 and MnCO3 powders via a hydrothermal process. X-ray pow-der diffraction (XRD) and field emission scanning elec-tron microscopy (FESEM) were used to characterize the products, and the magnetic susceptibility curve was also measured. In the whole process, the concentration of Mn2+ cations derived from MnCO3 dissolution plays a crucial role in the formation of β-Mn2V2O7 microtubes and hollow microspheres.
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