The photoluminescence(PL)peak of poly p-phenyl phenol(PPP)is at about 370-420nm excited by the light at 350nm.The absorption band edges and photon emitting peaks of the polymer are found the conjugated lengths depende...The photoluminescence(PL)peak of poly p-phenyl phenol(PPP)is at about 370-420nm excited by the light at 350nm.The absorption band edges and photon emitting peaks of the polymer are found the conjugated lengths dependent on molecular weight of polymer.In the transient luminescence measurement the lifetime of PL decay is determined to be 2.0ns which is supposed an evidence of polaron excitation recombination.The electroluminescence is observed with aluminum/PPP/indium-tinoxide cell.展开更多
The polymer electroluminescence (EL) device with PBD as carriers confinement layer yields bright blue emission having intensity of 300cd/m^(2),in same case the device without PBD layer have luminance only 44 cd/m^(2)....The polymer electroluminescence (EL) device with PBD as carriers confinement layer yields bright blue emission having intensity of 300cd/m^(2),in same case the device without PBD layer have luminance only 44 cd/m^(2).The effect of PBD layer on EL characteristic was studied.The results show that only in EL devices with PBD thick-ness over 30nm,the holes are completely confined in emitting layer.The luminance over 2000cd/m^(2) can be obtained by inserting an electron injecting layer between the negative electrode and PED to increase the electron injection.展开更多
By placing a hole blocking layer between the polymer and the metallic electrode,we have achieved improved efficiencies for blue electroluminescent devices fabricated with poly(N-vinylcarbazole)doped with 1,1,4,4,-tetr...By placing a hole blocking layer between the polymer and the metallic electrode,we have achieved improved efficiencies for blue electroluminescent devices fabricated with poly(N-vinylcarbazole)doped with 1,1,4,4,-tetraphenyl-1,3-butadiene as the emitter layer and with aluminum and indium/tin-oxide as the electron and hole injecting electrodes.This bilayer device yields bright blue emission having intensity of 300cd/m^(2),in same case the devices without hole blocking layer have luminance of only 44 cd/m^(2).展开更多
Blue-green electroluminescent diodes utilizing tris(8-Quinolino1ato)-aluminum doped poly(vinylcarbazole)have been demonstrated.A Schottky-type electroluminescent diode of the polymer film is driven at 20V and has a pe...Blue-green electroluminescent diodes utilizing tris(8-Quinolino1ato)-aluminum doped poly(vinylcarbazole)have been demonstrated.A Schottky-type electroluminescent diode of the polymer film is driven at 20V and has a peak emission wavelength of 490nm at room temperature with lifetime up to 4 h.展开更多
The synthesis of norvancomycin (NVan)-capped silver nanoparticles (Ag@NVan) and their notable in vitro antibacterial activities against E. coli, a Gram-negative bacterial strain (GNB), are reported here. Mercaptoaceti...The synthesis of norvancomycin (NVan)-capped silver nanoparticles (Ag@NVan) and their notable in vitro antibacterial activities against E. coli, a Gram-negative bacterial strain (GNB), are reported here. Mercaptoacetic acid-stabilized spherical silver nanoparticles with a diameter of 16±4 nm are prepared by a simple chemical reaction. The formation process of the silver nanoparticles is investigated by UV-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). NVan is then grafted to the terminal carboxyl of the mercaptoacetic acid in the presence of N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC). The TEM images of single bacteria treated with Ag@NVan show that plenty of Ag@NVan aggregate in the cell wall of E. coli. A possible antibacterial mechanism is proposed that silver nanoparticles may help destroy the stability of the outer membrane of E. coli, which makes NVan easier to bind to the nether part of the peptidoglycan structure. The antibacterial activities of silver nanoparticles on their own, together with the rigid polyvalent interaction between Ag@NVan and cell wall, enables Ag@NVan to be an effective inhibitor of GNB. This kind of bionanocomposites might be used as novel bactericidal materials and we also provide an effective synthesis method for preparing functional bioconjugated nanoparticles here.展开更多
Organic crystals constructed by pi-conjugated molecules have been paid great attention to in the field of organic optoelectronic materials. The superiorities of these organic crystal materials, such as high thermal st...Organic crystals constructed by pi-conjugated molecules have been paid great attention to in the field of organic optoelectronic materials. The superiorities of these organic crystal materials, such as high thermal stability, highly ordered structure, and high carrier mobility over the amorphous thin film ma-terials, make them attractive candidates for optoelectronic devices. Single crystal with definite struc-ture provides a model to investigate the basic interactions between the molecules (supramolecular interaction), and the relationship between molecular stacking modes and optoelectronic performance (luminescence and carrier mobility). Through modulating molecular arrangement in organic crystal, the luminescence efficiency of organic crystal has exceeded 80% and carrier mobility has been up to the level of 10 cm2·V?1·s?1. Amplified stimulated emission phenomena have been observed in many crys-tals. In this paper, we will emphatically introduce the progress in optoelectronic functional organic crystals and some correlative principle.展开更多
Glutathione peroxidase (GPx, EC1.11.1.9), an important anti-oxidative selenoenzyme, can catalyze the reduction of harmful hydroperoxides with concomitant glutathione, thereby protecting cells and other biological issu...Glutathione peroxidase (GPx, EC1.11.1.9), an important anti-oxidative selenoenzyme, can catalyze the reduction of harmful hydroperoxides with concomitant glutathione, thereby protecting cells and other biological issues against oxidative damage. It captures considerable interest in redesign of its function for either the mechanism study or the pharmacological development as an antioxidant. In order to de- velop a general strategy for specifically targeting and operating selenium in active sites of enzymes, the catalytically essential residue selenocysteine (Sec) was first successfully bioincorporated into the catalytic center of subtilisin by using an auxotrophic expression system. The studies of the catalytic activity and the steady-state kinetics demonstrated that selenosubtilisin is an excellent GPx-like bio- catalyst. In comparison with the chemically modified method, biosynthesis exhibits obvious advan- tages: Sec could be site-directly incorporated into active sites of enzymes to overcome the non-speci- ficity generated by chemical modification. This study provides an important strategy for specifically targeting and operating selenium in the active site of an enzyme.展开更多
The water-soluble Ag nanoparticles capped with novel zwitterionic thioalkylated phosphorylcholine were synthesized.The Ag nanoparticles showed remarkable stability in saline media with salt concen-trations as high as ...The water-soluble Ag nanoparticles capped with novel zwitterionic thioalkylated phosphorylcholine were synthesized.The Ag nanoparticles showed remarkable stability in saline media with salt concen-trations as high as 2.0 mol/L and plasma using UV-vis absorption spectroscopy.Similarly,compared with tiopronin and citrate-protected Ag nanoparticles,the zwitterionic phosphorylcholine Ag nanopar-ticles did not precipitate out of solution when charged polyelectrolytes or biopolymers were added.The zwitterionic phosphorylcholine might be a better ligand for stabilizing metal nanoparticles.展开更多
文摘The photoluminescence(PL)peak of poly p-phenyl phenol(PPP)is at about 370-420nm excited by the light at 350nm.The absorption band edges and photon emitting peaks of the polymer are found the conjugated lengths dependent on molecular weight of polymer.In the transient luminescence measurement the lifetime of PL decay is determined to be 2.0ns which is supposed an evidence of polaron excitation recombination.The electroluminescence is observed with aluminum/PPP/indium-tinoxide cell.
基金Supported by the National Natural Science Foundation of Chinaby Key Research Projection from the National Laboratory of Integrated Optical Electronics of Jilin University
文摘The polymer electroluminescence (EL) device with PBD as carriers confinement layer yields bright blue emission having intensity of 300cd/m^(2),in same case the device without PBD layer have luminance only 44 cd/m^(2).The effect of PBD layer on EL characteristic was studied.The results show that only in EL devices with PBD thick-ness over 30nm,the holes are completely confined in emitting layer.The luminance over 2000cd/m^(2) can be obtained by inserting an electron injecting layer between the negative electrode and PED to increase the electron injection.
文摘By placing a hole blocking layer between the polymer and the metallic electrode,we have achieved improved efficiencies for blue electroluminescent devices fabricated with poly(N-vinylcarbazole)doped with 1,1,4,4,-tetraphenyl-1,3-butadiene as the emitter layer and with aluminum and indium/tin-oxide as the electron and hole injecting electrodes.This bilayer device yields bright blue emission having intensity of 300cd/m^(2),in same case the devices without hole blocking layer have luminance of only 44 cd/m^(2).
文摘Blue-green electroluminescent diodes utilizing tris(8-Quinolino1ato)-aluminum doped poly(vinylcarbazole)have been demonstrated.A Schottky-type electroluminescent diode of the polymer film is driven at 20V and has a peak emission wavelength of 490nm at room temperature with lifetime up to 4 h.
基金Supported by the National Natural Science Foundation of China (Grant No. 50373036)Fok Ying Tung Education Foundation (Grant No. J20040212)
文摘The synthesis of norvancomycin (NVan)-capped silver nanoparticles (Ag@NVan) and their notable in vitro antibacterial activities against E. coli, a Gram-negative bacterial strain (GNB), are reported here. Mercaptoacetic acid-stabilized spherical silver nanoparticles with a diameter of 16±4 nm are prepared by a simple chemical reaction. The formation process of the silver nanoparticles is investigated by UV-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). NVan is then grafted to the terminal carboxyl of the mercaptoacetic acid in the presence of N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC). The TEM images of single bacteria treated with Ag@NVan show that plenty of Ag@NVan aggregate in the cell wall of E. coli. A possible antibacterial mechanism is proposed that silver nanoparticles may help destroy the stability of the outer membrane of E. coli, which makes NVan easier to bind to the nether part of the peptidoglycan structure. The antibacterial activities of silver nanoparticles on their own, together with the rigid polyvalent interaction between Ag@NVan and cell wall, enables Ag@NVan to be an effective inhibitor of GNB. This kind of bionanocomposites might be used as novel bactericidal materials and we also provide an effective synthesis method for preparing functional bioconjugated nanoparticles here.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20573040, 20474024, 90501001, 50303007)Ministry of Science and Technology of China (Grant No. 2002CB6134003), and PCSIRT.
文摘Organic crystals constructed by pi-conjugated molecules have been paid great attention to in the field of organic optoelectronic materials. The superiorities of these organic crystal materials, such as high thermal stability, highly ordered structure, and high carrier mobility over the amorphous thin film ma-terials, make them attractive candidates for optoelectronic devices. Single crystal with definite struc-ture provides a model to investigate the basic interactions between the molecules (supramolecular interaction), and the relationship between molecular stacking modes and optoelectronic performance (luminescence and carrier mobility). Through modulating molecular arrangement in organic crystal, the luminescence efficiency of organic crystal has exceeded 80% and carrier mobility has been up to the level of 10 cm2·V?1·s?1. Amplified stimulated emission phenomena have been observed in many crys-tals. In this paper, we will emphatically introduce the progress in optoelectronic functional organic crystals and some correlative principle.
基金the National Natural Science Foundation of China (Grant Nos 20534030 and 20725415)National Basic Research Program of China (Grant No. 2007CB808006) Innovative Research Team in University of China (Grant No. IRT0422)
文摘Glutathione peroxidase (GPx, EC1.11.1.9), an important anti-oxidative selenoenzyme, can catalyze the reduction of harmful hydroperoxides with concomitant glutathione, thereby protecting cells and other biological issues against oxidative damage. It captures considerable interest in redesign of its function for either the mechanism study or the pharmacological development as an antioxidant. In order to de- velop a general strategy for specifically targeting and operating selenium in active sites of enzymes, the catalytically essential residue selenocysteine (Sec) was first successfully bioincorporated into the catalytic center of subtilisin by using an auxotrophic expression system. The studies of the catalytic activity and the steady-state kinetics demonstrated that selenosubtilisin is an excellent GPx-like bio- catalyst. In comparison with the chemically modified method, biosynthesis exhibits obvious advan- tages: Sec could be site-directly incorporated into active sites of enzymes to overcome the non-speci- ficity generated by chemical modification. This study provides an important strategy for specifically targeting and operating selenium in the active site of an enzyme.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20774082 and 50703036)National High Technology Research and Development Program of China (Grant Nos. 2006AA03Z329 and 2006AA032444)Science and Technology Projects of Zhejiang Province (Grant No. 2007C24G2010020)
文摘The water-soluble Ag nanoparticles capped with novel zwitterionic thioalkylated phosphorylcholine were synthesized.The Ag nanoparticles showed remarkable stability in saline media with salt concen-trations as high as 2.0 mol/L and plasma using UV-vis absorption spectroscopy.Similarly,compared with tiopronin and citrate-protected Ag nanoparticles,the zwitterionic phosphorylcholine Ag nanopar-ticles did not precipitate out of solution when charged polyelectrolytes or biopolymers were added.The zwitterionic phosphorylcholine might be a better ligand for stabilizing metal nanoparticles.
