Based on ecological niche theory, Microcystis Aeruginosa(MA) immobilized in the complex of polyvinyl alcohol(PVA)and sodium alginate(SA) crosslinked by CaCl2, was treated as a new kind of special species, and its prop...Based on ecological niche theory, Microcystis Aeruginosa(MA) immobilized in the complex of polyvinyl alcohol(PVA)and sodium alginate(SA) crosslinked by CaCl2, was treated as a new kind of special species, and its properties were investigated.Chlorophyll a was used to characterize the bioactivity of the immobilized MA. Results reveal that the gel beads have mechanical strength and chemical stability even under non-sterile harsh conditions, which may be attributed to the rarely seen structure(including three different layers: dense surface, tubular-shaped divergent structure and honeycomb crystal lattice layer) of the immobilized MA determined by scanning electron microscope(SEM). SEM also displays that more quantity of MA is attached to the inwall after cultivation, which demonstrates that the MA within beads maintains high bioactivity. Removal capacities on phosphorous(P) removal in wastewater in the presence and absence of the BG-11 medium were examined, and the removal ratios are 80.3% and76.7%, respectively, which indicates that the beads without providing ample nutrients still have high capacity of P removal. In addition, control experiment, utilizing polyvinyl alcohol and sodium alginate(PVA-SA) beads without immobilized MA,demonstrates that MA within beads plays the key role in absorbing P.展开更多
The morphological change of St/DVB crosslinked gels during chloromethylation wasstudied by fluorescence spectroscopy using St/DVB crosslinked and hypercrosslinked gels as controlsamples. It has been found that with in...The morphological change of St/DVB crosslinked gels during chloromethylation wasstudied by fluorescence spectroscopy using St/DVB crosslinked and hypercrosslinked gels as controlsamples. It has been found that with increase of chlorine content, the excimer emission band (~325nm)approaches to vanish, while the intensity of multi-ring aggregate emission band (~420nm) quicklyreaches a maximum, and then decreases sharply accompanied by appearance ofa new broad bandcentred at ca 488nm which roughly coincides with the typical emission band of hypercrossllinkedSt/DVB gels. Mearwhile, the result of IR measurement suggests that methylene bridge between phenylrings forms and increases with chloromethylation process. These results are explained in terms ofaside reaction of post-crosslinking, which densifies the loosely crosslinked networks and undoes thedensely entangled microgel nuclei. As a result, the morphology of the crosslinked gels becom es morehomogeneous with chloromethylation.展开更多
Due to the increasing demand of replacing large capacity overhead lines with underground cables in Korea, KEPCO （Korea Electric Power Corporation） and LS Cable （LS Cable ＆ System） have developed 345 kV optical fi...Due to the increasing demand of replacing large capacity overhead lines with underground cables in Korea, KEPCO （Korea Electric Power Corporation） and LS Cable （LS Cable ＆ System） have developed 345 kV optical fiber composite XLPE （cross-linked polyethylene） 2,500 mm2 cable system. This system has been installed in Cheongna district of Incheon city. KEPCO and LS Cable are also planning to build the cooling system in a tunnel in order to reduce the ambient temperature caused by currents. In this paper, the process of development, field installation, and final inspection test of the complete system will be described.展开更多
The oscillating voltage test is a nondestructive detection method for partial discharge of XLPE （cross linked polyethylene） cable and has been applied recently. This paper made three kinds of varying severity artifi...The oscillating voltage test is a nondestructive detection method for partial discharge of XLPE （cross linked polyethylene） cable and has been applied recently. This paper made three kinds of varying severity artificial defect models of cable joints in 10 kV XLPE cable. Oscillating voltage is applied to the model, by use of pulse current method to detect partial discharge signals. In order to study the statistical characteristics of partial discharge of cable joint under the oscillating voltage, three-dimensional statistical map has been made. The results show that for the same kind of defects, with the increases of the defect severity, the discharge interval extended, the magnitude and the number of partial discharge increase, for different kinds of defects, obvious differences exist among the maps, this may established a foundation for the further study of the partial discharge pattern recognition of XLPE cable under oscillating voltage.展开更多
Two kinds of St/DVB copolymer beeds containing (1 - pyrenyl) formyl and(1 -pyrenyl) methyl groups respectively have been synthesized by both functionalization and copolymerization. The fluorescence spectra of the swo...Two kinds of St/DVB copolymer beeds containing (1 - pyrenyl) formyl and(1 -pyrenyl) methyl groups respectively have been synthesized by both functionalization and copolymerization. The fluorescence spectra of the swollen polymers synthesized are similar in shape to those of the corresponding model compounds, whilethe intensity ratio of excimer to monomer shows clear dependence on the contents ofthe pyrene groups.展开更多
A series of 4,4＇-disubstituted-[2,2＇]-bipyridines, featuring electron withdrawing/donating functional groups such as amino, chloro, nitro, ethoxycarbonyl, carboxy, methyl, methoxy and hydroxymethyl, have been syn- t...A series of 4,4＇-disubstituted-[2,2＇]-bipyridines, featuring electron withdrawing/donating functional groups such as amino, chloro, nitro, ethoxycarbonyl, carboxy, methyl, methoxy and hydroxymethyl, have been syn- thesized and employed in the copolymerization of carbon monoxide （CO） and styrene. The available bipyridine and its derivatives were coordinated with palladium （ II ） acetate for catalyzing the copolymerization of CO and styrene, and the concomitant polyketone was characterized by means of t3C NMR, FTIR, differential scanning calo- rimetry （DSC） and element analysis techniques concerning its structure and thermal performance. The effect of dif- ferent electron-donating and electron-withdrawing groups on catalyst performance and molecular weight of co- polymer was studied under certain experimental condition. It has been proved that the enhancement of electron donating and conjugative effects on bipyridine ligand will not only improve the catalytic activity of the composi- tion, but also increase the molecular weight of the as-prepared polyketone. The catalytic activity is the highest in hydroxymethyl substituted 2,2＇-bipyridine ligand（l 356 gSTCO/（gPd · h））, when the molecular weight and polydispersity index of the polyketone are Mn = 8 502, Mw = 1 3440 and Mw/Mn = 1.581, respectively.展开更多
Preparation of thermoplastic elastomer of Polypropylene-SIR 10 rubber blends with addition of DCP （dicumil peroxide） as initiator and DVB （divinylbenzene） as a crosslinker has been done. Blends of Polypropylene-SI...Preparation of thermoplastic elastomer of Polypropylene-SIR 10 rubber blends with addition of DCP （dicumil peroxide） as initiator and DVB （divinylbenzene） as a crosslinker has been done. Blends of Polypropylene-SIR 10 rubber with variation of weight 60/40 （w/w）, 50/50 （w/w） and 40/60 （w/w） with variation concentration of DCP and DVB 1 phr, 2 phr and 3 phr were mixed into internal mixer at temperature 180 ℃. Then, the blends were pressed at 185 ℃ and specimen were molded according to the ASTM D638. The characterization were carried out based on tensile strength testing, crosslink percentage, morphology surface analysis with SEM and fungtional group analysis with FTIR （Fourier Transform Infra Red）. The result showed that the blends of Polypropilene-SIR 10 rubber 60/40 （w/w） with 2 phr DCP and 1 phr DVB posses a higher tensile strength with value 1.37 Kgf/mm2 and value of elongation at break 17.58%, and value of percentage crosslink 82.4%. The result of morphology test with SEM showed that the blend was well homogenous. Spectra analysis with FT-IR has shown physical interaction among components of the blends.展开更多
A silylated PNP ligand with asymmetric structure was synthesized using(γ-aminopropyl)triethoxysilane and chlorodiphenyl phosphine as raw materials.The optimal synthetic conditions of the PNP ligand were obtained by c...A silylated PNP ligand with asymmetric structure was synthesized using(γ-aminopropyl)triethoxysilane and chlorodiphenyl phosphine as raw materials.The optimal synthetic conditions of the PNP ligand were obtained by conditional experiments and were as follows:dichloromethane was solvent,triethylamine was acid acceptor,the mole ratio of chlorodiphenylphosphine and(γ-aminopropyl)triethoxysilane was 2.1∶1,the dropping temperature of chlorodiphenylphosphine was-5℃,the dropping time was 30 min,the reaction temperature was 25℃and the reaction time was 12 h.Under the conditions,the yield of the silylated PNP ligand was 91.20%.Based on grey correlation analysis,the dropping temperature was the main factor for the yield of the silylated PNP ligand.The single-active central chromium catalyst based on the silylated PNP ligand was synthesized by complexation reaction with the silylated PNP ligand and chromium chloride tetrahydrofuran complex as materials,and the yield was 95.25%.The chemical structures of the silylated PNP ligand and the corresponding chromium catalyst were confirmed by elemental analysis,FT-IR,^(1)H NMR,MS and ICP.The single-active central chromium catalyst based on the silylated PNP ligand had good catalytic activity for ethylene oligomerization,and the content of C_(8)olefin was 72.40%,which was superior to Si-Schiff-Cr based on intermolecular coordination.展开更多
基金Projects(51178172,51308076)supported by the National Natural Science Foundation of ChinaProject(13JJ4107)supported by Hunan Provincial Natural Science Foundation,ChinaProject(K1207026-31)supported by Changsha Planning Project of Science and Technology,China
文摘Based on ecological niche theory, Microcystis Aeruginosa(MA) immobilized in the complex of polyvinyl alcohol(PVA)and sodium alginate(SA) crosslinked by CaCl2, was treated as a new kind of special species, and its properties were investigated.Chlorophyll a was used to characterize the bioactivity of the immobilized MA. Results reveal that the gel beads have mechanical strength and chemical stability even under non-sterile harsh conditions, which may be attributed to the rarely seen structure(including three different layers: dense surface, tubular-shaped divergent structure and honeycomb crystal lattice layer) of the immobilized MA determined by scanning electron microscope(SEM). SEM also displays that more quantity of MA is attached to the inwall after cultivation, which demonstrates that the MA within beads maintains high bioactivity. Removal capacities on phosphorous(P) removal in wastewater in the presence and absence of the BG-11 medium were examined, and the removal ratios are 80.3% and76.7%, respectively, which indicates that the beads without providing ample nutrients still have high capacity of P removal. In addition, control experiment, utilizing polyvinyl alcohol and sodium alginate(PVA-SA) beads without immobilized MA,demonstrates that MA within beads plays the key role in absorbing P.
基金National Natural Scientific Foundation of China (Project grant No.29574165 29928003+1 种基金 29874019) National Natural Scientific Foundation of Tianjin (Project grant No.013604011)
文摘The morphological change of St/DVB crosslinked gels during chloromethylation wasstudied by fluorescence spectroscopy using St/DVB crosslinked and hypercrosslinked gels as controlsamples. It has been found that with increase of chlorine content, the excimer emission band (~325nm)approaches to vanish, while the intensity of multi-ring aggregate emission band (~420nm) quicklyreaches a maximum, and then decreases sharply accompanied by appearance ofa new broad bandcentred at ca 488nm which roughly coincides with the typical emission band of hypercrossllinkedSt/DVB gels. Mearwhile, the result of IR measurement suggests that methylene bridge between phenylrings forms and increases with chloromethylation process. These results are explained in terms ofaside reaction of post-crosslinking, which densifies the loosely crosslinked networks and undoes thedensely entangled microgel nuclei. As a result, the morphology of the crosslinked gels becom es morehomogeneous with chloromethylation.
文摘Due to the increasing demand of replacing large capacity overhead lines with underground cables in Korea, KEPCO （Korea Electric Power Corporation） and LS Cable （LS Cable ＆ System） have developed 345 kV optical fiber composite XLPE （cross-linked polyethylene） 2,500 mm2 cable system. This system has been installed in Cheongna district of Incheon city. KEPCO and LS Cable are also planning to build the cooling system in a tunnel in order to reduce the ambient temperature caused by currents. In this paper, the process of development, field installation, and final inspection test of the complete system will be described.
文摘The oscillating voltage test is a nondestructive detection method for partial discharge of XLPE （cross linked polyethylene） cable and has been applied recently. This paper made three kinds of varying severity artificial defect models of cable joints in 10 kV XLPE cable. Oscillating voltage is applied to the model, by use of pulse current method to detect partial discharge signals. In order to study the statistical characteristics of partial discharge of cable joint under the oscillating voltage, three-dimensional statistical map has been made. The results show that for the same kind of defects, with the increases of the defect severity, the discharge interval extended, the magnitude and the number of partial discharge increase, for different kinds of defects, obvious differences exist among the maps, this may established a foundation for the further study of the partial discharge pattern recognition of XLPE cable under oscillating voltage.
文摘Two kinds of St/DVB copolymer beeds containing (1 - pyrenyl) formyl and(1 -pyrenyl) methyl groups respectively have been synthesized by both functionalization and copolymerization. The fluorescence spectra of the swollen polymers synthesized are similar in shape to those of the corresponding model compounds, whilethe intensity ratio of excimer to monomer shows clear dependence on the contents ofthe pyrene groups.
基金Supported by Tianjin Natural Science Foundation(No.07JCYBJC00600)
文摘A series of 4,4＇-disubstituted-[2,2＇]-bipyridines, featuring electron withdrawing/donating functional groups such as amino, chloro, nitro, ethoxycarbonyl, carboxy, methyl, methoxy and hydroxymethyl, have been syn- thesized and employed in the copolymerization of carbon monoxide （CO） and styrene. The available bipyridine and its derivatives were coordinated with palladium （ II ） acetate for catalyzing the copolymerization of CO and styrene, and the concomitant polyketone was characterized by means of t3C NMR, FTIR, differential scanning calo- rimetry （DSC） and element analysis techniques concerning its structure and thermal performance. The effect of dif- ferent electron-donating and electron-withdrawing groups on catalyst performance and molecular weight of co- polymer was studied under certain experimental condition. It has been proved that the enhancement of electron donating and conjugative effects on bipyridine ligand will not only improve the catalytic activity of the composi- tion, but also increase the molecular weight of the as-prepared polyketone. The catalytic activity is the highest in hydroxymethyl substituted 2,2＇-bipyridine ligand（l 356 gSTCO/（gPd · h））, when the molecular weight and polydispersity index of the polyketone are Mn = 8 502, Mw = 1 3440 and Mw/Mn = 1.581, respectively.
文摘Preparation of thermoplastic elastomer of Polypropylene-SIR 10 rubber blends with addition of DCP （dicumil peroxide） as initiator and DVB （divinylbenzene） as a crosslinker has been done. Blends of Polypropylene-SIR 10 rubber with variation of weight 60/40 （w/w）, 50/50 （w/w） and 40/60 （w/w） with variation concentration of DCP and DVB 1 phr, 2 phr and 3 phr were mixed into internal mixer at temperature 180 ℃. Then, the blends were pressed at 185 ℃ and specimen were molded according to the ASTM D638. The characterization were carried out based on tensile strength testing, crosslink percentage, morphology surface analysis with SEM and fungtional group analysis with FTIR （Fourier Transform Infra Red）. The result showed that the blends of Polypropilene-SIR 10 rubber 60/40 （w/w） with 2 phr DCP and 1 phr DVB posses a higher tensile strength with value 1.37 Kgf/mm2 and value of elongation at break 17.58%, and value of percentage crosslink 82.4%. The result of morphology test with SEM showed that the blend was well homogenous. Spectra analysis with FT-IR has shown physical interaction among components of the blends.
基金supported by Key Research and Development Project of Heilongjiang Province(JD22A026)
文摘A silylated PNP ligand with asymmetric structure was synthesized using(γ-aminopropyl)triethoxysilane and chlorodiphenyl phosphine as raw materials.The optimal synthetic conditions of the PNP ligand were obtained by conditional experiments and were as follows:dichloromethane was solvent,triethylamine was acid acceptor,the mole ratio of chlorodiphenylphosphine and(γ-aminopropyl)triethoxysilane was 2.1∶1,the dropping temperature of chlorodiphenylphosphine was-5℃,the dropping time was 30 min,the reaction temperature was 25℃and the reaction time was 12 h.Under the conditions,the yield of the silylated PNP ligand was 91.20%.Based on grey correlation analysis,the dropping temperature was the main factor for the yield of the silylated PNP ligand.The single-active central chromium catalyst based on the silylated PNP ligand was synthesized by complexation reaction with the silylated PNP ligand and chromium chloride tetrahydrofuran complex as materials,and the yield was 95.25%.The chemical structures of the silylated PNP ligand and the corresponding chromium catalyst were confirmed by elemental analysis,FT-IR,^(1)H NMR,MS and ICP.The single-active central chromium catalyst based on the silylated PNP ligand had good catalytic activity for ethylene oligomerization,and the content of C_(8)olefin was 72.40%,which was superior to Si-Schiff-Cr based on intermolecular coordination.
