The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of manufacture.However,to-date,laboratory testi...The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of manufacture.However,to-date,laboratory testing remains the internationally accepted practice for identifying and quantifying the taggants stipulated in the Convention.In this project,portable FTIR and Raman instruments were tested for their ability to detect 2,3-dimethyl-2,3-dinitrobutane(DMDNB),the chemical marker incorporated in plastic explosives that are manufactured within Australia.While both FTIR and Raman instruments detected solid DMDNB(98%purity),field analysis of plastic explosives at an Australian Defence establishment showed that both FTIR and Raman spectra were matched the relevant explosive(RDX or PETN),rather than the DMDNB taggant.For all three plastic explosives tested,the concentration of DMDNB was measured by SPME-GC-MS to be between 1.8 and 2%,greater than the minimum 1%concentration stipulated by the Marplex Convention.Additional testing with a plastic explosive analogue confirmed that the minor absorption peaks that would characterize low concentrations of DMDNB were masked by absorption bands from other compounds within the solid.Thus,while both FTIR and Raman spectroscopy are suitable for detection of plastic explosives,neither rely on the presence of DMDNB for detection.It is likely that similar results would be found for other taggants stipulated by the Marplex Convention,given they are also present in concentrations less than 1%.展开更多
A new biflavonoid, 2,3-dihydro-5,5″,7,7,4′-pentahydroxy-6,6＂-dimethyl-[3′-O-4″]-biflavone 1 and two known biflavonoids 2,3＂-dihydroochnaflavone 2 and 2″,3″-dihydro-3′,3-biapigenin 3 were isolated from the her...A new biflavonoid, 2,3-dihydro-5,5″,7,7,4′-pentahydroxy-6,6＂-dimethyl-[3′-O-4″]-biflavone 1 and two known biflavonoids 2,3＂-dihydroochnaflavone 2 and 2″,3″-dihydro-3′,3-biapigenin 3 were isolated from the herb of Selaginella labordei Hieron. ex Christ. Their structures were elucidated by spectroscopic methods. ？2009 Ke Li Chert. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
A series of narrow band-gap conjugated copolymers(PFO-DDQ)derived from 9,9-dioctylfluorene(DOF)and 2,3-dimethyl-5,8-dithien-2-yl-quinoxalines(DDQ)is prepared by the palladium-catalyzed Suzuki coupling reaction with th...A series of narrow band-gap conjugated copolymers(PFO-DDQ)derived from 9,9-dioctylfluorene(DOF)and 2,3-dimethyl-5,8-dithien-2-yl-quinoxalines(DDQ)is prepared by the palladium-catalyzed Suzuki coupling reaction with the molar feed ratio of DDQ at around 1%,5%,15%,30%and 50%,respectively.The obtained polymers are readily soluble in common organic solvents.The solutions and the thin solid films of the copolymers absorb light from 300-590 nm with two absorbance peaks at around 380 and 490 nm.The intensity of 490 nm peak increases with the increasing DDQ content in the polymers.Efficient energy transfer due to exciton trapping on narrow-band-gap DDQ sites has been observed.The PL emission consists exclusively of DDQ unit emission at around 591-643 nm depending on the DDQ content in solid film.The EL emission peaks are red-shifted from 580 nm for PFO-DDQ1 to 635 nm for PFO-DDQ50.The highest external quantum efficiency achieved with the device configuration ITO/PEDOT/PVK/PFO-DDQ15/Ba/Al is 1.33%with a luminous efficiency 1.54 cd/A.Bulk heterojunction photovoltaic cells fabricated from composite films of PFO-DDQ30 copolymer and[6,6]-phenyl C61 butyric acid methyl ester(PCBM)as electron donor and electron acceptor,respectively in device configuration:ITO/PEDOT:PSS/PFODDQ30:PCBM/PFPNBr/Al shows power conversion efficiencies of 1.18%with open-circuit voltage(V_(oc))of 0.90 V and short-circuit current density(J_(sc))of 2.66 mA/cm^(2)under an AM1.5 solar simulator(100 mW/cm^(2)).The photocurrent response wavelengths of the PVCs based on PFO-DDQ30/PCBM blends covers 300-700 nm.This indicates that these kinds of low band-gap polymers are promising candidates for polymeric solar cells and red light-emitting diodes.展开更多
基金funded by the Defence Science Technology Group(DSTG)。
文摘The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of manufacture.However,to-date,laboratory testing remains the internationally accepted practice for identifying and quantifying the taggants stipulated in the Convention.In this project,portable FTIR and Raman instruments were tested for their ability to detect 2,3-dimethyl-2,3-dinitrobutane(DMDNB),the chemical marker incorporated in plastic explosives that are manufactured within Australia.While both FTIR and Raman instruments detected solid DMDNB(98%purity),field analysis of plastic explosives at an Australian Defence establishment showed that both FTIR and Raman spectra were matched the relevant explosive(RDX or PETN),rather than the DMDNB taggant.For all three plastic explosives tested,the concentration of DMDNB was measured by SPME-GC-MS to be between 1.8 and 2%,greater than the minimum 1%concentration stipulated by the Marplex Convention.Additional testing with a plastic explosive analogue confirmed that the minor absorption peaks that would characterize low concentrations of DMDNB were masked by absorption bands from other compounds within the solid.Thus,while both FTIR and Raman spectroscopy are suitable for detection of plastic explosives,neither rely on the presence of DMDNB for detection.It is likely that similar results would be found for other taggants stipulated by the Marplex Convention,given they are also present in concentrations less than 1%.
基金supported by the National Natural Science Foundation of China(No.30470193).
文摘A new biflavonoid, 2,3-dihydro-5,5″,7,7,4′-pentahydroxy-6,6＂-dimethyl-[3′-O-4″]-biflavone 1 and two known biflavonoids 2,3＂-dihydroochnaflavone 2 and 2″,3″-dihydro-3′,3-biapigenin 3 were isolated from the herb of Selaginella labordei Hieron. ex Christ. Their structures were elucidated by spectroscopic methods. ？2009 Ke Li Chert. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金the National Natural Science Foundation of China(Grant No.50433030)the Ministry of Science and Technology(No.2002CB613404)for financial support.
文摘A series of narrow band-gap conjugated copolymers(PFO-DDQ)derived from 9,9-dioctylfluorene(DOF)and 2,3-dimethyl-5,8-dithien-2-yl-quinoxalines(DDQ)is prepared by the palladium-catalyzed Suzuki coupling reaction with the molar feed ratio of DDQ at around 1%,5%,15%,30%and 50%,respectively.The obtained polymers are readily soluble in common organic solvents.The solutions and the thin solid films of the copolymers absorb light from 300-590 nm with two absorbance peaks at around 380 and 490 nm.The intensity of 490 nm peak increases with the increasing DDQ content in the polymers.Efficient energy transfer due to exciton trapping on narrow-band-gap DDQ sites has been observed.The PL emission consists exclusively of DDQ unit emission at around 591-643 nm depending on the DDQ content in solid film.The EL emission peaks are red-shifted from 580 nm for PFO-DDQ1 to 635 nm for PFO-DDQ50.The highest external quantum efficiency achieved with the device configuration ITO/PEDOT/PVK/PFO-DDQ15/Ba/Al is 1.33%with a luminous efficiency 1.54 cd/A.Bulk heterojunction photovoltaic cells fabricated from composite films of PFO-DDQ30 copolymer and[6,6]-phenyl C61 butyric acid methyl ester(PCBM)as electron donor and electron acceptor,respectively in device configuration:ITO/PEDOT:PSS/PFODDQ30:PCBM/PFPNBr/Al shows power conversion efficiencies of 1.18%with open-circuit voltage(V_(oc))of 0.90 V and short-circuit current density(J_(sc))of 2.66 mA/cm^(2)under an AM1.5 solar simulator(100 mW/cm^(2)).The photocurrent response wavelengths of the PVCs based on PFO-DDQ30/PCBM blends covers 300-700 nm.This indicates that these kinds of low band-gap polymers are promising candidates for polymeric solar cells and red light-emitting diodes.
