Some results on the molecular-beam epitaxial growth of HgCdTe focusing on the requirements of the 3rd generation infrared focal plane arrays are described. Good uniformity is observed over 75mm HgCdTe epilayers,and th...Some results on the molecular-beam epitaxial growth of HgCdTe focusing on the requirements of the 3rd generation infrared focal plane arrays are described. Good uniformity is observed over 75mm HgCdTe epilayers,and the deviation in cutoff wavelength is within 0. 1μm at 80K. A variety of surface defects are observed and the formation mechanism is discussed. The average density of surface defects in 75mm HgCdTe epiluyers is found to be less than 300cm^-2. It is found that the surface sticking coefficient of As during HgCdTe growth is very low and is sensitive to growth temperature, being only -1 × 10^-4 at 170℃. The activation energy of As in HgCdTe was determined to be 19.5meV,which decreases as （Na - Nd）^1/3 with a slope of 3.1 × 10^-5 meV · cm. The diffusion coefficients of As in HgCdTe of 1.0 ± 0,9 × 10^-16,8 ± 3 × 10^- is, and 1.5 ± 0.9 × 10^-13 cm^2/s are obtained at temperatures of 240,380, and 440℃, respectively under Hg-saturated pressure. The MBE-grown HgCdTe is incorporated into FPA fabrications,and the preliminary results are presented.展开更多
The contents of total and methyl mercury in scalp hair samples of 1179 fishermenliving at a typical Hg-polluted region in Northeast China and 27 lying-in womenand their new born babies in Beijing have been determined ...The contents of total and methyl mercury in scalp hair samples of 1179 fishermenliving at a typical Hg-polluted region in Northeast China and 27 lying-in womenand their new born babies in Beijing have been determined by illstrumental neutronactivation analysis, gas chromatography (electron coupling) and other techniqlles.Only 18 of all fishermen have the Hg contents above 5 ig/g, which indicates that theHg pollution there has been substantially alleviated. The longitudinal Hg patternsof the lying-in women show a gradually lowering tendency during pregnant period.Further, the Hg contents of the new-born babies are generally above or close to those oftheir mothers, confirming the mechanism that the methyl Hg, an organic species of Hgwith high toxicity, is readily able to penetrate the placental barrier and accumulatedin fetus. Thus, the mercury poison hajs occurred at the early stage of pregnancy.展开更多
Elemental mercury（Hg^0）re-emissions from slurries and solutions were evaluated in a lab-scale simulated scrubber.Oxidized mercury（Hg^2 ＋）standard solution was injected into the simulated scrubber at a desired rat...Elemental mercury（Hg^0）re-emissions from slurries and solutions were evaluated in a lab-scale simulated scrubber.Oxidized mercury（Hg^2 ＋）standard solution was injected into the simulated scrubber at a desired rate to simulate absorbing and dissolving of Hg^2 ＋in the flue gas across wet flue gas desulfurization（WFGD）systems. PS analytical mercury analyzer was used to continuously determine Hg0re-emission concentrations in the carrier gas from the scrubber.Sulfite ion in the slurry of CaSO3 was validated to reduce Hg ^2＋to Hg^ 0,while no Hg ^0 re-emission occurred from slurries of CaSO4 and CaO.Transitional metal ions with low chemical valence such as Fe^2 ＋,Pb ^2＋,Ni ^2＋, AsO2^-and Cu ^＋were used to prepare solutions with concentration levels of mmol·L^-1.Reduction reaction of Hg^2 ＋to Hg 0was observed from these solutions.Reduction capabilities for the different transitional metal ions in the solutions were：Pb^2 ＋〉Cu ^＋〉Fe^ 2＋〉 AsO2^-〉Ni ^2＋.展开更多
A bifunctional probe 1 with iminocoumarin scaffold demonstrated different responses for Cu2+and Hg2+.In fluorescence mode of probe 1,the intensity at 528 nm was quenched severely upon the addition of Cu2+or Hg2+.Meanw...A bifunctional probe 1 with iminocoumarin scaffold demonstrated different responses for Cu2+and Hg2+.In fluorescence mode of probe 1,the intensity at 528 nm was quenched severely upon the addition of Cu2+or Hg2+.Meanwhile,a new fluorescence band at 574 nm appeared in the case of Hg2+.In its UV-Vis absorption mode,significant hypochromic shift for Cu2+and bathochromic shift for Hg2+occurred,which are in agreement with the observation of distinct color changes.In addition,probe 1can be used for the construction of a molecular logic gate with NOR and INHIBIT logic functions.展开更多
A non-sulfur chemosensor based on an easy to prepare double naphthalene Schiff base is reported for the colorimetric and fluorometric dual-channel sensing of Hg2+ ions by taking advantage of the twisted intramolecular...A non-sulfur chemosensor based on an easy to prepare double naphthalene Schiff base is reported for the colorimetric and fluorometric dual-channel sensing of Hg2+ ions by taking advantage of the twisted intramolecular charge transfer (TICT) mechanism. This work provides a novel approach for the selective recognition of mercury ions. Moreover, this sensor serves as a potential recyclable component in sensing materials and the complex L-Hg2+ (L = 1-[(2-naphthalenylimino)methyl]-2-naphthalenol) can therefore be used as a fluorescent sensor for iodine anions. Notably, the color changes are very significant and all the recognition and recycling processes can be observed by the naked eye.展开更多
文摘Some results on the molecular-beam epitaxial growth of HgCdTe focusing on the requirements of the 3rd generation infrared focal plane arrays are described. Good uniformity is observed over 75mm HgCdTe epilayers,and the deviation in cutoff wavelength is within 0. 1μm at 80K. A variety of surface defects are observed and the formation mechanism is discussed. The average density of surface defects in 75mm HgCdTe epiluyers is found to be less than 300cm^-2. It is found that the surface sticking coefficient of As during HgCdTe growth is very low and is sensitive to growth temperature, being only -1 × 10^-4 at 170℃. The activation energy of As in HgCdTe was determined to be 19.5meV,which decreases as （Na - Nd）^1/3 with a slope of 3.1 × 10^-5 meV · cm. The diffusion coefficients of As in HgCdTe of 1.0 ± 0,9 × 10^-16,8 ± 3 × 10^- is, and 1.5 ± 0.9 × 10^-13 cm^2/s are obtained at temperatures of 240,380, and 440℃, respectively under Hg-saturated pressure. The MBE-grown HgCdTe is incorporated into FPA fabrications,and the preliminary results are presented.
文摘The contents of total and methyl mercury in scalp hair samples of 1179 fishermenliving at a typical Hg-polluted region in Northeast China and 27 lying-in womenand their new born babies in Beijing have been determined by illstrumental neutronactivation analysis, gas chromatography (electron coupling) and other techniqlles.Only 18 of all fishermen have the Hg contents above 5 ig/g, which indicates that theHg pollution there has been substantially alleviated. The longitudinal Hg patternsof the lying-in women show a gradually lowering tendency during pregnant period.Further, the Hg contents of the new-born babies are generally above or close to those oftheir mothers, confirming the mechanism that the methyl Hg, an organic species of Hgwith high toxicity, is readily able to penetrate the placental barrier and accumulatedin fetus. Thus, the mercury poison hajs occurred at the early stage of pregnancy.
基金Supported by the US Agency for International Development(USAID)cooperation agreement(486-A-00-06-000140-00)
文摘Elemental mercury（Hg^0）re-emissions from slurries and solutions were evaluated in a lab-scale simulated scrubber.Oxidized mercury（Hg^2 ＋）standard solution was injected into the simulated scrubber at a desired rate to simulate absorbing and dissolving of Hg^2 ＋in the flue gas across wet flue gas desulfurization（WFGD）systems. PS analytical mercury analyzer was used to continuously determine Hg0re-emission concentrations in the carrier gas from the scrubber.Sulfite ion in the slurry of CaSO3 was validated to reduce Hg ^2＋to Hg^ 0,while no Hg ^0 re-emission occurred from slurries of CaSO4 and CaO.Transitional metal ions with low chemical valence such as Fe^2 ＋,Pb ^2＋,Ni ^2＋, AsO2^-and Cu ^＋were used to prepare solutions with concentration levels of mmol·L^-1.Reduction reaction of Hg^2 ＋to Hg 0was observed from these solutions.Reduction capabilities for the different transitional metal ions in the solutions were：Pb^2 ＋〉Cu ^＋〉Fe^ 2＋〉 AsO2^-〉Ni ^2＋.
基金financially supported by the National Natural Science Foundation of China(21001058)the National Science Foundation for Fostering Talents in Basic Research of the NSFC(J1103307)+2 种基金the Fundamental Research Funds for the Central Universities(lzujbky-2013-ct02)Program for Changjiang Scholars and Innovative Research Team in University(IRT1138)the "111" Project of Ministry of Education
文摘A bifunctional probe 1 with iminocoumarin scaffold demonstrated different responses for Cu2+and Hg2+.In fluorescence mode of probe 1,the intensity at 528 nm was quenched severely upon the addition of Cu2+or Hg2+.Meanwhile,a new fluorescence band at 574 nm appeared in the case of Hg2+.In its UV-Vis absorption mode,significant hypochromic shift for Cu2+and bathochromic shift for Hg2+occurred,which are in agreement with the observation of distinct color changes.In addition,probe 1can be used for the construction of a molecular logic gate with NOR and INHIBIT logic functions.
基金supported by the National Natural Science Foundation of China (21064006, 21161018)the Natural Science Foundation of Gansu Province (1010RJZA018)the Program for Changjiang Scholars and Innovative Research Teams in Universities of the Ministry of Education of China (IRT1177)
文摘A non-sulfur chemosensor based on an easy to prepare double naphthalene Schiff base is reported for the colorimetric and fluorometric dual-channel sensing of Hg2+ ions by taking advantage of the twisted intramolecular charge transfer (TICT) mechanism. This work provides a novel approach for the selective recognition of mercury ions. Moreover, this sensor serves as a potential recyclable component in sensing materials and the complex L-Hg2+ (L = 1-[(2-naphthalenylimino)methyl]-2-naphthalenol) can therefore be used as a fluorescent sensor for iodine anions. Notably, the color changes are very significant and all the recognition and recycling processes can be observed by the naked eye.
