The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the ...The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb^2＋ and Cd〉 （0, 0.5, 1, 2, 4, 6 and 8 mg/L）. The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the Synechocystis sp. PCC 6803 cells became evident with the increased （〉4 mg/L Pb^2＋） metal concentration. The photosynthetic apparatus （thylakoid membranes） were found to be the worst affected. Deteriorated or completely destroyed thylakoid membranes have made large empty spaces in the cell interior. In addition, at the highest concentration （8 mg/L pb^2＋）, the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations （0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/L pb^2＋）, both metals inhibited the growth in a dose-dependent manner as incubation progressed. Pigment contents （chlorophyll a, 13 carotene and phycocyanin） were also decreased with increasing metal concentration. Cells exposed to 6 mg/L Pb^2＋, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll a, 13 carotene and phycocyanin respectively over the control. Corresponding reductions for the same CdZ＋concentrations were 57.83, 48.94 and 56.90%. Lethal concentration （96 h LC50） values （3.47 mg/L Cd^2＋ and 12.11 mg/L Pb^2＋） indicated that Synechocystis sp. PCC 6803 is more vulnerable to Cd^2＋ than Pb^2＋.展开更多
An AlN Layer grown by an ALE has been developed to improve the growth quality of GaN on Al 2O 3 substrate by low pressure metalorganic vapor phase epitaxy (LP MOVPE). An ALE AlN layer grown on Al 2O 3 substrate has a ...An AlN Layer grown by an ALE has been developed to improve the growth quality of GaN on Al 2O 3 substrate by low pressure metalorganic vapor phase epitaxy (LP MOVPE). An ALE AlN layer grown on Al 2O 3 substrate has a high quality and the structure is similar to GaN, this AlN layer can release the stress between Al 2O 3 substrate and GaN epilayer. By using this method, the orientation of substrate is extended to GaN epilayer, and the column tilt and the twist are improved, so as to obtain the device quality GaN.展开更多
Heavy metals currently pose one of the most serious problems in terms of environmental protection. We analysed the effect of cadmium and mercury salts upon chlorophyll fluorescence emision of Microcystis aeruginosa, C...Heavy metals currently pose one of the most serious problems in terms of environmental protection. We analysed the effect of cadmium and mercury salts upon chlorophyll fluorescence emision of Microcystis aeruginosa, Cylindrospermopsis raciborskii and Aphanizomenon gracile. Time of incubation （3, 12 and 24 h） and salts concentration（1 μM, 10 μM, 100μM） influenced the emision. The higher the salt concentration and the longer the time of incubation, the greater the influence on inhibition of chlorophyll fluorescence was observed. Our results might indicate that nontoxic strains of M. aeruginosa MAKR0205 can have a high tolerance to heavy metal ions and ability of their detoxication. Further studies are necessary to confirm their potential ability in the water purification.展开更多
A phytoremediation field trial was established on a site contaminated with Cu, Pb and Zn in the City of Montreal （Canada） using Brassicajuncea, Salix miyabeana and Salix viminalis. The study compared metal content i...A phytoremediation field trial was established on a site contaminated with Cu, Pb and Zn in the City of Montreal （Canada） using Brassicajuncea, Salix miyabeana and Salix viminalis. The study compared metal content in plant tissues of each species at the end of the first growing season and assessed the effects of EDTA as a chelating agent to increase availability of metals for the plants. Brassicajuncea accumulated more metals （Cu, Pb and Zn） in aerial parts than in roots, whereas the willows accumulated Cu and Pb mainly in roots and Zn in aerial parts （mostly in leaves）. EDTA increased metal transfer in Brassica but had no effect on the two willow species. After one growing season, the total biomass yield of Brassica juncea was higher than that of the willows, and consequently, total metal accumulation by the plants was also greater. However, the high yield of willows over several years may make them more successful in brownfield phytoremediation.展开更多
We carried out first-principles calculations to investigate the electronic properties of the monolayer blue phosphorene(BlueP)decorated by the group-IVB transition-metal adatoms(Cr,Mo and W),and found that the Cr-deco...We carried out first-principles calculations to investigate the electronic properties of the monolayer blue phosphorene(BlueP)decorated by the group-IVB transition-metal adatoms(Cr,Mo and W),and found that the Cr-decorated BlueP is a magnetic half metal,while the Mo-and W-decorated BlueP are semiconductors with band gaps smaller than 0.2 eV.Compressive biaxial strains make the band gaps close and reopen,and band inversions occur during this process,which induces topological transitions in the Mo-decorated BlueP(with strain of-5.75%)and W-decorated BlueP(with strain of-4.25%)from normal insulators to topological insulators(TIs).The TI gap is 94 meV for the Mo-decorated BlueP and218 me V for the W-decorated BlueP.Such large TI gaps demonstrate the possibility to engineer topological phases in the monolayer BlueP with transition-metal adatoms at high temperature.展开更多
This paper deals with two species of the Cerambycid genus Cyanagapanthia Breuning from China, including a new species: C. aurecens sp. nov. A key to the genus is provided. The type specimen is deposited i...This paper deals with two species of the Cerambycid genus Cyanagapanthia Breuning from China, including a new species: C. aurecens sp. nov. A key to the genus is provided. The type specimen is deposited in the Insect Collection, Nakai University, China.展开更多
Growth of blue InGaN based LED structures on sapphire wafers from 2 inch to 8 inch in diameter was investigated using the Veeco K465 MOCVD platform. Our results indicate that the same pressure,rotation rate and hydrid...Growth of blue InGaN based LED structures on sapphire wafers from 2 inch to 8 inch in diameter was investigated using the Veeco K465 MOCVD platform. Our results indicate that the same pressure,rotation rate and hydride flows can be used for all wafer sizes. AFM and X-ray studies reveal that all wafer sizes have comparable high-quality crystallinity and defect levels for GaN and InGaN/GaN MQW growth. Although the larger diameter wafers exhibit larger wafer bow due to lattice and thermal mismatch,with proper wafer pocket design,good wavelength and thickness uniformity can be obtained for all wafer sizes.展开更多
文摘The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb^2＋ and Cd〉 （0, 0.5, 1, 2, 4, 6 and 8 mg/L）. The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the Synechocystis sp. PCC 6803 cells became evident with the increased （〉4 mg/L Pb^2＋） metal concentration. The photosynthetic apparatus （thylakoid membranes） were found to be the worst affected. Deteriorated or completely destroyed thylakoid membranes have made large empty spaces in the cell interior. In addition, at the highest concentration （8 mg/L pb^2＋）, the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations （0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/L pb^2＋）, both metals inhibited the growth in a dose-dependent manner as incubation progressed. Pigment contents （chlorophyll a, 13 carotene and phycocyanin） were also decreased with increasing metal concentration. Cells exposed to 6 mg/L Pb^2＋, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll a, 13 carotene and phycocyanin respectively over the control. Corresponding reductions for the same CdZ＋concentrations were 57.83, 48.94 and 56.90%. Lethal concentration （96 h LC50） values （3.47 mg/L Cd^2＋ and 12.11 mg/L Pb^2＋） indicated that Synechocystis sp. PCC 6803 is more vulnerable to Cd^2＋ than Pb^2＋.
文摘An AlN Layer grown by an ALE has been developed to improve the growth quality of GaN on Al 2O 3 substrate by low pressure metalorganic vapor phase epitaxy (LP MOVPE). An ALE AlN layer grown on Al 2O 3 substrate has a high quality and the structure is similar to GaN, this AlN layer can release the stress between Al 2O 3 substrate and GaN epilayer. By using this method, the orientation of substrate is extended to GaN epilayer, and the column tilt and the twist are improved, so as to obtain the device quality GaN.
文摘Heavy metals currently pose one of the most serious problems in terms of environmental protection. We analysed the effect of cadmium and mercury salts upon chlorophyll fluorescence emision of Microcystis aeruginosa, Cylindrospermopsis raciborskii and Aphanizomenon gracile. Time of incubation （3, 12 and 24 h） and salts concentration（1 μM, 10 μM, 100μM） influenced the emision. The higher the salt concentration and the longer the time of incubation, the greater the influence on inhibition of chlorophyll fluorescence was observed. Our results might indicate that nontoxic strains of M. aeruginosa MAKR0205 can have a high tolerance to heavy metal ions and ability of their detoxication. Further studies are necessary to confirm their potential ability in the water purification.
文摘A phytoremediation field trial was established on a site contaminated with Cu, Pb and Zn in the City of Montreal （Canada） using Brassicajuncea, Salix miyabeana and Salix viminalis. The study compared metal content in plant tissues of each species at the end of the first growing season and assessed the effects of EDTA as a chelating agent to increase availability of metals for the plants. Brassicajuncea accumulated more metals （Cu, Pb and Zn） in aerial parts than in roots, whereas the willows accumulated Cu and Pb mainly in roots and Zn in aerial parts （mostly in leaves）. EDTA increased metal transfer in Brassica but had no effect on the two willow species. After one growing season, the total biomass yield of Brassica juncea was higher than that of the willows, and consequently, total metal accumulation by the plants was also greater. However, the high yield of willows over several years may make them more successful in brownfield phytoremediation.
基金the National Natural Science Foundation of China(No.11574223)the Natural Science Foundation of Jiangsu Province(BK20150303)the Six Talent Peaks Project of Jiangsu Province(2019-XCL-081)。
文摘We carried out first-principles calculations to investigate the electronic properties of the monolayer blue phosphorene(BlueP)decorated by the group-IVB transition-metal adatoms(Cr,Mo and W),and found that the Cr-decorated BlueP is a magnetic half metal,while the Mo-and W-decorated BlueP are semiconductors with band gaps smaller than 0.2 eV.Compressive biaxial strains make the band gaps close and reopen,and band inversions occur during this process,which induces topological transitions in the Mo-decorated BlueP(with strain of-5.75%)and W-decorated BlueP(with strain of-4.25%)from normal insulators to topological insulators(TIs).The TI gap is 94 meV for the Mo-decorated BlueP and218 me V for the W-decorated BlueP.Such large TI gaps demonstrate the possibility to engineer topological phases in the monolayer BlueP with transition-metal adatoms at high temperature.
文摘This paper deals with two species of the Cerambycid genus Cyanagapanthia Breuning from China, including a new species: C. aurecens sp. nov. A key to the genus is provided. The type specimen is deposited in the Insect Collection, Nakai University, China.
文摘Growth of blue InGaN based LED structures on sapphire wafers from 2 inch to 8 inch in diameter was investigated using the Veeco K465 MOCVD platform. Our results indicate that the same pressure,rotation rate and hydride flows can be used for all wafer sizes. AFM and X-ray studies reveal that all wafer sizes have comparable high-quality crystallinity and defect levels for GaN and InGaN/GaN MQW growth. Although the larger diameter wafers exhibit larger wafer bow due to lattice and thermal mismatch,with proper wafer pocket design,good wavelength and thickness uniformity can be obtained for all wafer sizes.
