One of the main food crops in the world,rice can accumulate high levels of arsenic from flooded paddy soils,which seriously threatens human health.Soaking,a common processing method for brown rice products,especially ...One of the main food crops in the world,rice can accumulate high levels of arsenic from flooded paddy soils,which seriously threatens human health.Soaking,a common processing method for brown rice products,especially for brown rice noodles,was investigated in this study.Japonica rice(Dao Hua Xiang No.2)and Indica rice(Ye Xiang You No.3)were selected for studying the effects of soaking on arsenic concentrations,species,and distributions.Results revealed that soaking can efficiently remove arsenic in these two rice varieties,and the main part of removal is endosperm with the maximal rate of about 40%.Inorganic arsenic(I-As)(about 85%)is the main species of arsenic reduction.Meanwhile,the variations of four other elements(i.e.,Mg,Ca,Zn,and Fe)were analyzed.Collectively,the findings of this study indicate that soaking can efficiently remove arsenic in brown rice under controlled soaking conditions,which thereby reduces the arsenic intake for brown rice customers.展开更多
Objective To study the incidence of leukocytosis and retinoic acid （RA） syndrome in newly diagnosed and relapsed acute promyelocytic leukemia （APL） patients treated with arsenic trioxide （ATO）. Methods Thirty pa...Objective To study the incidence of leukocytosis and retinoic acid （RA） syndrome in newly diagnosed and relapsed acute promyelocytic leukemia （APL） patients treated with arsenic trioxide （ATO）. Methods Thirty patients with newly diagnosed or relapsed APL received ATO for remission induction at the dose of 10 mg/d. RA syndrome was defined when patient was with one or more of the following signs or symptoms： fever, dyspnea, serous cavity effusion, muscular pain, pulmonary infiltration, weight gain, or pulmonary infiltration on chest X-ray. Results Twenty-three （77%） patients achieved complete remission, mean time to remission was 37. 1 days. Leukocytosis was observed in 14 （47%） patients, mean time to leukocytosis was 12. 7 days, median baseline leukocyte count for patients with leukocytosis was 3.1 x 109/L, which was higher than that for patients who did not de,.＇elop leukocytosis （2.6 × 10^9/L, z = - 2. 635, P = 0. 008）. No other cytotoxic therapy was administered, and the leukocytosis resolved in all cases. The RA syndrome was observed in 9 （30%） patients, mean time to diagnose of RA syndrome was 13.9 days, median baseline leukocyte count for patients with RA syndrome was 3.6 × 10^9/L, which was higher than that for patients who did not develop RA syndrome （2. 6 × 10^9/L, z = - 1. 909, P =0. 046）. No patient died of RA syndrome. Conclusion Leukocytosis and RA syndrome are associated with ATO and baseline leukocyte count respectively, and there is distinct link between leukocytosis and RA syndrome.展开更多
Objective: To further understand the possible mechanisms of arsenic sulfide (realgar) in the treatment of acute promyelocytic leukemia (APL). Methods: All-trans retinoic acid (ATRA)-susceptible APL cell line (NB4 cell...Objective: To further understand the possible mechanisms of arsenic sulfide (realgar) in the treatment of acute promyelocytic leukemia (APL). Methods: All-trans retinoic acid (ATRA)-susceptible APL cell line (NB4 cells) and ATRA-resistant APL cell line (MR2 subclone) were used as models in vitro. At various times after incubated with various concentrations of realgar, NB4 and MR2 cells were observed by cell viability , cell proliferation and cell morphology; cell cycle and the expression of Annexin V were assayed by flow cytometry. Results: Cell viability and proliferation of NB4 and MR2 cells were inhibited after the treatment, to some extent, in a dose and time dependent manner. 177 - 711g/L of realgar treated NB4 and MR2 cell presented morphologically some features of apoptotic cells such as intact cell membrane, chromatin condensation and nuclear fragmentation, apoptosis body could be found by electron microscopy as well. Sub-Gl cells and cell cycle arrest were observed by flow cytometry. The proportion of Annexin V -FITC+/PI cells , which represent apoptotic cells, was up-regulated. Conclusion: Realgar could induce apoptosis of acute promyelocytic leukemia cell despite its susceptibility to retinoic acid in the way that may be different from retinoic acid.展开更多
Objective To study the effects of constantly slow intravenous arsenic trioxide （As2O2） infusion regimen on decreasing leukocytosis in vivo and in vitro. Methods Three kinds of leukemia cells, NB4, K562, and acute p...Objective To study the effects of constantly slow intravenous arsenic trioxide （As2O2） infusion regimen on decreasing leukocytosis in vivo and in vitro. Methods Three kinds of leukemia cells, NB4, K562, and acute promyelocyfic leukemia （APL） cells, were cultured in the media with constant concentration and varying concentrations of As2O3 respectively for 24 hours. Seventyfive patients were enrolled in two groups randomly. In trial group, 37 patients received continuously slow intravenous As2O3 infusion regimen for 24 hours with an infusion rate of 8 drips per minute and total infusion duration of about 18- 21 hours daily. In control group, 38 patients received routine regimen with an infusion rate of 45-55 drips per minute and total infusion duration of about 2-3 hours daily for 24 hours. The daily As2O3 dosage was 0. 16 mg/kg. The intracellular arsenic concentration was measured by atomic fluorescence assay. The apoptosis rate of cells, CD33 ^- CD11b ^＋ cells, and CD33^ ＋ CD11b^ - cells were monitored by flow cytometry. Results The apoptosis rates of NB4, K562, and APL leukemia cells in the media with constant As2O3 concentration were 56.6% ±2.4%, 27.6% ±3.1%, and 52.2% ±2. 8%, respectively, which were significantly higher than those with changing As2O3 concentration （23.2% ±2. 1%, 11.0% ±2.5%, and 21.0% ±2.5%, respectively, P〈 0.01）. The apoptosis rates of APL, M2 type acute myeloid leukemia （AML-M2）, and chronic myeloid leukemia （CML） patients in the trial group （28.5% ±1.9%, 9.5% ±0.6%, and 12.5% ±1.8% ） were also significantly higher than those in control group （8.5% ± 2. 2%, 2. 9% ± 0. 8%, and 4. 5% ± 1.2% ; P 〈 0.05 ）. The ratios of CD33 ~ CD11b^- and CD33^- CD11b^＋ cells in control group were significantly higher than those in trial group. Conclusion The continuously slow intravenous As2O3 infusion regimen can obtain high efficiency of apoptosis and low differentiation proportion, relieve leukocytosis, and gain maximal therapeutic benefit.展开更多
Arsenic （As） in the soils of South-Eastern Bangladesh is not rely a threat for the health of millions of people but also a problem for plant growth due to its higher concentration in soil. Gmelina arborea Linn. is a...Arsenic （As） in the soils of South-Eastern Bangladesh is not rely a threat for the health of millions of people but also a problem for plant growth due to its higher concentration in soil. Gmelina arborea Linn. is a promising fast growing tree species in Bangladesh which has dso a potential to be planted in arsenic contaminated areas. This study tssessed the role of arbuscular mycorrhizal （AM） fungi on the growth of 7. arborea in arsenic amended soils at nursery stage. Before sowing ;eeds, soils were treated with four different concentrations （10 mg.kg^-1, 25 mg.kg^-1, 50 mg.kg^-1, and 100 mg.kg^-1） of Arsenic. Growth parameters length of shoot and root, collar diameter, fresh and dry weight of shoot and root） of the plant, and mycorrhizal root colonization and spore population in the rhizosphere soil of G. arborea were recorded. Mycorrhizal seedlings showed better growth than non-mycorrhizal eedlings. Myeorrhizal seedlings planted in soil with 10-mg.kg^-1 arsenic howed best performance in terms of growth, biomass and mycorrhizal ：olonization, compared to other treatments with higher concentration of Lrsenie. With increasing arsenic concentration, growth of seedlings, nycorrhizal infection rate and spore population, all decreased ignificantly （p〈0.05）. The mycorrhizal seedlings had as much as 40% higher increment in total growth and 2.4 times higher increment in biomass compared to non-mycorrhizal seedlings. The study clearly indicated that mycorrhizal inoculation could reduce the harmful effects of arsenic on the initial growth of G. arborea Linn. in degraded soil at nursery stage.展开更多
This paper carries out the First principles calculation of the crystal structures （zinc blende （B3） and rocksalt （B1）） and phase transition of boron arsenic （BAs） based on the density-functional theory. Using ...This paper carries out the First principles calculation of the crystal structures （zinc blende （B3） and rocksalt （B1）） and phase transition of boron arsenic （BAs） based on the density-functional theory. Using the relation between enthalpy and pressure, it finds that the transition phase from the B3 structural to the B] structural occurs at the pressure of l13.42GPa. Then the elastic constants Cll, C12, C44, bulk modulus, shear modulus, Young modulus, anisotropy factor, Kleinman parameter and Poisson ratio are discussed in detail for two polymorphs of BAs. The results of the structural parameters and elastic properties in B3 structure are in good agreement with the available theoretical and experimental values.展开更多
Using first-principles calculations, we investigate the two-dimensional arsenic nanosheet isolated from bulk gray arsenic. Its dynamical stability is confirmed by phonon calculations and molecular dynamics analyzing. ...Using first-principles calculations, we investigate the two-dimensional arsenic nanosheet isolated from bulk gray arsenic. Its dynamical stability is confirmed by phonon calculations and molecular dynamics analyzing. The arsenic sheet is an indirect band gap semiconductor with a band gap of 2.21 e V in the hybrid HSE06 functional calculations. The valence band maximum（VBM） and the conduction band minimum（CBM） are mainly occupied by the 4p orbitals of arsenic atoms,which is consistent with the partial charge densities of VBM and CBM. The charge density of the VBM G point has the character of a π bond, which originates from p orbitals. Furthermore, tensile and compressive strains are applied in the armchair and zigzag directions, related to the tensile deformations of zigzag and armchair nanotubes, respectively. We find that the ultimate strain in zigzag deformation is 0.13, smaller than 0.18 of armchair deformation. The limit compressive stresses of single-layer arsenic along armchair and zigzag directions are-4.83 GPa and-4.76 GPa with corresponding strains of-0.15 and-0.14, respectively.展开更多
Arsenic can diffuse into high-κ dielectrics during OaAs-based metal oxide semiconductor transistor process, which causes the degradation of gate dielectrics. To explore the origins of the degradation, we employ nonlo...Arsenic can diffuse into high-κ dielectrics during OaAs-based metal oxide semiconductor transistor process, which causes the degradation of gate dielectrics. To explore the origins of the degradation, we employ nonlocal B3LYP hybrid functional to study arsenic related defects in ZrO2. Via band alignments between the OaAs and ZrO2, we are able to determine the defect formation energy in the GaAs relative to the ZrO2 band gap and assess how they will affect the device performance. Arsenic at the interstitial site serves as a source of positive fixed charge while at the oxygen or zirconium substitutional site changes its charge state within the band gap of GaAs. Moreover, it is found that arsenic related defects produce conduction band offset reduction and gap states, which will increase the gate leakage current.展开更多
Chemical extraction, bioremediation, and electrodialytic processes have been extensively studied for removal of copper, chromium, and arsenic from wood treated with chromated copper arsenate （CCA）. However, one prob...Chemical extraction, bioremediation, and electrodialytic processes have been extensively studied for removal of copper, chromium, and arsenic from wood treated with chromated copper arsenate （CCA）. However, one problem has not been addressed： the effects of wood species and retention levels on remediation efficiency. The objectives of this study were to investigate the effects of wood species and retention levels on removal of copper, chromium, and arsenic from CCA-treated wood samples using sodium hypochlorite. Our results showed that sodium hypochlorite （NaOC1） was very effective for removal of copper, chromium, and arsenic from CCA-C treated milled wood samples for all three species used in this study. The Cu, Cr, and As extraction efficiencies for red pine were 95 % Cu, 97 % Cr and 94 % As, for maple were 95 % Cu, 97 % Cr, and 98 % As at 4.0 kg m-3 retention levels, and for aspen were 95 % Cu, 92% Cr, and 91% As at 9.6 kg m-3 retention level, respectively. However, the results showed that wood species and initial retention levels of CCA-treated wood products played very impor- tant roles in terms of removal of Cu, Cr, and As.展开更多
A novel porous nanocomposite,cross-linked chitosan and polyethylene glycol(PEG) bead-supported MnFe_(2) O_(4) nanoparticles(CPM),was developed as an efficient adsorbent to remove metalloid(As(Ⅲ))and heavy metals(Cd(...A novel porous nanocomposite,cross-linked chitosan and polyethylene glycol(PEG) bead-supported MnFe_(2) O_(4) nanoparticles(CPM),was developed as an efficient adsorbent to remove metalloid(As(Ⅲ))and heavy metals(Cd(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ)).The characteristics of CPM showed a porous structure,well dispersed MnFe_(2) O_(4),and several of hydroxyl and amino groups(-OH,-NH_(2)).Batch experiments demonstrated that the best adsorption property of As(Ⅲ),Cd(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ) was achieved within 8 h with maximum adsorption capacities of 9.90,9.73,43.94,and 11.98 mg/g,respectively.Competitive and synergistic effects(particularly precipitation) were included in the co-adsorption mechanism of As(Ⅲ) and heavy metals.Thereinto,As(Ⅲ) was partly oxidized by MnFe_(2) O_(4) to As(V),and both were coordinated on MnFe_(2) O_(4) nanoparticles.Pb(Ⅱ) could also bind to MnFe_(2) O_(4) by ion exchange and electrostatic attraction.Furthermore,Cd(Ⅱ) and Cu(Ⅱ) tended to be coordinated on chitosan.Therefore,CPM can serve as a remediation material for water and soil co-contaminated with As(Ⅲ) and heavy metals.展开更多
A liquid encapsulated melt zone process has been developed for single crystal growth of GaAs.Single crystals of 40mm long have been grown with this technique.To avoid unwanted nucleation events and maintain a constant...A liquid encapsulated melt zone process has been developed for single crystal growth of GaAs.Single crystals of 40mm long have been grown with this technique.To avoid unwanted nucleation events and maintain a constant crystal diameter,from top to bottom growth using a short zone with a convex zone surface was found to give the best results.An arsenic overpressure way used to in conjunction with a B_(2)O_(3) encapsulant in order to suppress arsenic dissociation from the melt and maintain the stoichiometry of the crystal.展开更多
Polycrystalline BAsx(x=0.80-1.10)compounds with different boron-to-arsenic elemental molar ratios were synthesized by a high-pressure and high-temperature sintering method.Compared with other ambient-pressure synthesi...Polycrystalline BAsx(x=0.80-1.10)compounds with different boron-to-arsenic elemental molar ratios were synthesized by a high-pressure and high-temperature sintering method.Compared with other ambient-pressure synthesis methods,high pressure can significantly promote the reaction speed as well as the reaction yield.As the content of arsenic increases from x=0.91 to 1.10,the thermal conductivity of BAsx gradually increases from 53 to 65 W·m-1·K-1.Furthermore,the temperature dependence of thermal conductivities of these samples reveals an Umklapp scattering due to the increasing phonon population.This work provides a highly efficient method for polycrystalline BAs synthesis.展开更多
基金the Special National Key Research and Development Plan[grant number 2016YFD0400204]the Ministry of Science and Technology of the People’s Republic of China[grant number2015FY111300]the Technology Innovation Program of the Chinese Academy of Agricultural Sciences[grant number CAAS-ASTIP-201X-IAPPST].
文摘One of the main food crops in the world,rice can accumulate high levels of arsenic from flooded paddy soils,which seriously threatens human health.Soaking,a common processing method for brown rice products,especially for brown rice noodles,was investigated in this study.Japonica rice(Dao Hua Xiang No.2)and Indica rice(Ye Xiang You No.3)were selected for studying the effects of soaking on arsenic concentrations,species,and distributions.Results revealed that soaking can efficiently remove arsenic in these two rice varieties,and the main part of removal is endosperm with the maximal rate of about 40%.Inorganic arsenic(I-As)(about 85%)is the main species of arsenic reduction.Meanwhile,the variations of four other elements(i.e.,Mg,Ca,Zn,and Fe)were analyzed.Collectively,the findings of this study indicate that soaking can efficiently remove arsenic in brown rice under controlled soaking conditions,which thereby reduces the arsenic intake for brown rice customers.
文摘Objective To study the incidence of leukocytosis and retinoic acid （RA） syndrome in newly diagnosed and relapsed acute promyelocytic leukemia （APL） patients treated with arsenic trioxide （ATO）. Methods Thirty patients with newly diagnosed or relapsed APL received ATO for remission induction at the dose of 10 mg/d. RA syndrome was defined when patient was with one or more of the following signs or symptoms： fever, dyspnea, serous cavity effusion, muscular pain, pulmonary infiltration, weight gain, or pulmonary infiltration on chest X-ray. Results Twenty-three （77%） patients achieved complete remission, mean time to remission was 37. 1 days. Leukocytosis was observed in 14 （47%） patients, mean time to leukocytosis was 12. 7 days, median baseline leukocyte count for patients with leukocytosis was 3.1 x 109/L, which was higher than that for patients who did not de,.＇elop leukocytosis （2.6 × 10^9/L, z = - 2. 635, P = 0. 008）. No other cytotoxic therapy was administered, and the leukocytosis resolved in all cases. The RA syndrome was observed in 9 （30%） patients, mean time to diagnose of RA syndrome was 13.9 days, median baseline leukocyte count for patients with RA syndrome was 3.6 × 10^9/L, which was higher than that for patients who did not develop RA syndrome （2. 6 × 10^9/L, z = - 1. 909, P =0. 046）. No patient died of RA syndrome. Conclusion Leukocytosis and RA syndrome are associated with ATO and baseline leukocyte count respectively, and there is distinct link between leukocytosis and RA syndrome.
基金Supported by the Foundation of Chinese Medicine Administration of Shaanxi Province (1999-02, 2001-008).
文摘Objective: To further understand the possible mechanisms of arsenic sulfide (realgar) in the treatment of acute promyelocytic leukemia (APL). Methods: All-trans retinoic acid (ATRA)-susceptible APL cell line (NB4 cells) and ATRA-resistant APL cell line (MR2 subclone) were used as models in vitro. At various times after incubated with various concentrations of realgar, NB4 and MR2 cells were observed by cell viability , cell proliferation and cell morphology; cell cycle and the expression of Annexin V were assayed by flow cytometry. Results: Cell viability and proliferation of NB4 and MR2 cells were inhibited after the treatment, to some extent, in a dose and time dependent manner. 177 - 711g/L of realgar treated NB4 and MR2 cell presented morphologically some features of apoptotic cells such as intact cell membrane, chromatin condensation and nuclear fragmentation, apoptosis body could be found by electron microscopy as well. Sub-Gl cells and cell cycle arrest were observed by flow cytometry. The proportion of Annexin V -FITC+/PI cells , which represent apoptotic cells, was up-regulated. Conclusion: Realgar could induce apoptosis of acute promyelocytic leukemia cell despite its susceptibility to retinoic acid in the way that may be different from retinoic acid.
基金Supported by National Natural Science Foundation (30370507) Heilongjiang Excellent Youth Foundation (2003AA9CS188-12).
文摘Objective To study the effects of constantly slow intravenous arsenic trioxide （As2O2） infusion regimen on decreasing leukocytosis in vivo and in vitro. Methods Three kinds of leukemia cells, NB4, K562, and acute promyelocyfic leukemia （APL） cells, were cultured in the media with constant concentration and varying concentrations of As2O3 respectively for 24 hours. Seventyfive patients were enrolled in two groups randomly. In trial group, 37 patients received continuously slow intravenous As2O3 infusion regimen for 24 hours with an infusion rate of 8 drips per minute and total infusion duration of about 18- 21 hours daily. In control group, 38 patients received routine regimen with an infusion rate of 45-55 drips per minute and total infusion duration of about 2-3 hours daily for 24 hours. The daily As2O3 dosage was 0. 16 mg/kg. The intracellular arsenic concentration was measured by atomic fluorescence assay. The apoptosis rate of cells, CD33 ^- CD11b ^＋ cells, and CD33^ ＋ CD11b^ - cells were monitored by flow cytometry. Results The apoptosis rates of NB4, K562, and APL leukemia cells in the media with constant As2O3 concentration were 56.6% ±2.4%, 27.6% ±3.1%, and 52.2% ±2. 8%, respectively, which were significantly higher than those with changing As2O3 concentration （23.2% ±2. 1%, 11.0% ±2.5%, and 21.0% ±2.5%, respectively, P〈 0.01）. The apoptosis rates of APL, M2 type acute myeloid leukemia （AML-M2）, and chronic myeloid leukemia （CML） patients in the trial group （28.5% ±1.9%, 9.5% ±0.6%, and 12.5% ±1.8% ） were also significantly higher than those in control group （8.5% ± 2. 2%, 2. 9% ± 0. 8%, and 4. 5% ± 1.2% ; P 〈 0.05 ）. The ratios of CD33 ~ CD11b^- and CD33^- CD11b^＋ cells in control group were significantly higher than those in trial group. Conclusion The continuously slow intravenous As2O3 infusion regimen can obtain high efficiency of apoptosis and low differentiation proportion, relieve leukocytosis, and gain maximal therapeutic benefit.
文摘Arsenic （As） in the soils of South-Eastern Bangladesh is not rely a threat for the health of millions of people but also a problem for plant growth due to its higher concentration in soil. Gmelina arborea Linn. is a promising fast growing tree species in Bangladesh which has dso a potential to be planted in arsenic contaminated areas. This study tssessed the role of arbuscular mycorrhizal （AM） fungi on the growth of 7. arborea in arsenic amended soils at nursery stage. Before sowing ;eeds, soils were treated with four different concentrations （10 mg.kg^-1, 25 mg.kg^-1, 50 mg.kg^-1, and 100 mg.kg^-1） of Arsenic. Growth parameters length of shoot and root, collar diameter, fresh and dry weight of shoot and root） of the plant, and mycorrhizal root colonization and spore population in the rhizosphere soil of G. arborea were recorded. Mycorrhizal seedlings showed better growth than non-mycorrhizal eedlings. Myeorrhizal seedlings planted in soil with 10-mg.kg^-1 arsenic howed best performance in terms of growth, biomass and mycorrhizal ：olonization, compared to other treatments with higher concentration of Lrsenie. With increasing arsenic concentration, growth of seedlings, nycorrhizal infection rate and spore population, all decreased ignificantly （p〈0.05）. The mycorrhizal seedlings had as much as 40% higher increment in total growth and 2.4 times higher increment in biomass compared to non-mycorrhizal seedlings. The study clearly indicated that mycorrhizal inoculation could reduce the harmful effects of arsenic on the initial growth of G. arborea Linn. in degraded soil at nursery stage.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10974139 and 10964002)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20050610010)+1 种基金the Science-Technology Foundation of Guizhou Province of China (Grant Nos. [2009]2066 and [2009]06)the project of Aiding Elites’ Research Condition of Guizhou Province of China (Grant No. TZJF-2008-42)
文摘This paper carries out the First principles calculation of the crystal structures （zinc blende （B3） and rocksalt （B1）） and phase transition of boron arsenic （BAs） based on the density-functional theory. Using the relation between enthalpy and pressure, it finds that the transition phase from the B3 structural to the B] structural occurs at the pressure of l13.42GPa. Then the elastic constants Cll, C12, C44, bulk modulus, shear modulus, Young modulus, anisotropy factor, Kleinman parameter and Poisson ratio are discussed in detail for two polymorphs of BAs. The results of the structural parameters and elastic properties in B3 structure are in good agreement with the available theoretical and experimental values.
基金supported by the Henan Joint Funds of the National Natural Science Foundation of China(Grant Nos.U1304612 and U1404608)the National Natural Science Foundation of China(Grant Nos.51374132 and 11404175)+1 种基金the Special Fund for Theoretical Physics of China(Grant No.11247222)Nanyang Normal University Science Foundation,China(Grant Nos.ZX2012018 and ZX2013019)
文摘Using first-principles calculations, we investigate the two-dimensional arsenic nanosheet isolated from bulk gray arsenic. Its dynamical stability is confirmed by phonon calculations and molecular dynamics analyzing. The arsenic sheet is an indirect band gap semiconductor with a band gap of 2.21 e V in the hybrid HSE06 functional calculations. The valence band maximum（VBM） and the conduction band minimum（CBM） are mainly occupied by the 4p orbitals of arsenic atoms,which is consistent with the partial charge densities of VBM and CBM. The charge density of the VBM G point has the character of a π bond, which originates from p orbitals. Furthermore, tensile and compressive strains are applied in the armchair and zigzag directions, related to the tensile deformations of zigzag and armchair nanotubes, respectively. We find that the ultimate strain in zigzag deformation is 0.13, smaller than 0.18 of armchair deformation. The limit compressive stresses of single-layer arsenic along armchair and zigzag directions are-4.83 GPa and-4.76 GPa with corresponding strains of-0.15 and-0.14, respectively.
基金Supported by the Key Project of Education Department of China under Grant No 211035the Science Foundation from Education Department of Liaoning Province under Grant No L2014445
文摘Arsenic can diffuse into high-κ dielectrics during OaAs-based metal oxide semiconductor transistor process, which causes the degradation of gate dielectrics. To explore the origins of the degradation, we employ nonlocal B3LYP hybrid functional to study arsenic related defects in ZrO2. Via band alignments between the OaAs and ZrO2, we are able to determine the defect formation energy in the GaAs relative to the ZrO2 band gap and assess how they will affect the device performance. Arsenic at the interstitial site serves as a source of positive fixed charge while at the oxygen or zirconium substitutional site changes its charge state within the band gap of GaAs. Moreover, it is found that arsenic related defects produce conduction band offset reduction and gap states, which will increase the gate leakage current.
文摘Chemical extraction, bioremediation, and electrodialytic processes have been extensively studied for removal of copper, chromium, and arsenic from wood treated with chromated copper arsenate （CCA）. However, one problem has not been addressed： the effects of wood species and retention levels on remediation efficiency. The objectives of this study were to investigate the effects of wood species and retention levels on removal of copper, chromium, and arsenic from CCA-treated wood samples using sodium hypochlorite. Our results showed that sodium hypochlorite （NaOC1） was very effective for removal of copper, chromium, and arsenic from CCA-C treated milled wood samples for all three species used in this study. The Cu, Cr, and As extraction efficiencies for red pine were 95 % Cu, 97 % Cr and 94 % As, for maple were 95 % Cu, 97 % Cr, and 98 % As at 4.0 kg m-3 retention levels, and for aspen were 95 % Cu, 92% Cr, and 91% As at 9.6 kg m-3 retention level, respectively. However, the results showed that wood species and initial retention levels of CCA-treated wood products played very impor- tant roles in terms of removal of Cu, Cr, and As.
基金funded by the National Key Research and Development Project (No. 2020YFC1807700)the National Key Research and Development Project (No. 2019YFC1805900)+4 种基金the Youth Fund Project of GRINM (No. 12008)the Youth Fund Project of GRINM (No. 12119)the Open Foundation of State Key Laboratory of Mineral Processing (No. BGRIMM-KJSKL-2020-07)the Open Foundation of State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization (No. 2021P4FZG13A)the National Natural Science Foundation of China (No. 51704028)。
文摘A novel porous nanocomposite,cross-linked chitosan and polyethylene glycol(PEG) bead-supported MnFe_(2) O_(4) nanoparticles(CPM),was developed as an efficient adsorbent to remove metalloid(As(Ⅲ))and heavy metals(Cd(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ)).The characteristics of CPM showed a porous structure,well dispersed MnFe_(2) O_(4),and several of hydroxyl and amino groups(-OH,-NH_(2)).Batch experiments demonstrated that the best adsorption property of As(Ⅲ),Cd(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ) was achieved within 8 h with maximum adsorption capacities of 9.90,9.73,43.94,and 11.98 mg/g,respectively.Competitive and synergistic effects(particularly precipitation) were included in the co-adsorption mechanism of As(Ⅲ) and heavy metals.Thereinto,As(Ⅲ) was partly oxidized by MnFe_(2) O_(4) to As(V),and both were coordinated on MnFe_(2) O_(4) nanoparticles.Pb(Ⅱ) could also bind to MnFe_(2) O_(4) by ion exchange and electrostatic attraction.Furthermore,Cd(Ⅱ) and Cu(Ⅱ) tended to be coordinated on chitosan.Therefore,CPM can serve as a remediation material for water and soil co-contaminated with As(Ⅲ) and heavy metals.
文摘A liquid encapsulated melt zone process has been developed for single crystal growth of GaAs.Single crystals of 40mm long have been grown with this technique.To avoid unwanted nucleation events and maintain a constant crystal diameter,from top to bottom growth using a short zone with a convex zone surface was found to give the best results.An arsenic overpressure way used to in conjunction with a B_(2)O_(3) encapsulant in order to suppress arsenic dissociation from the melt and maintain the stoichiometry of the crystal.
基金Supported by the National Key R&D Program of China(Grant Nos.2018YFE0103200 and 2018YFA0305700)the National Natural Science Foundation of China(Grant Nos.51772324,11934017,11921004,and 11574378)the Chinese Academy of Sciences(Grant Nos.QYZDB–SSW–SLH013 and GJHZ1773)。
文摘Polycrystalline BAsx(x=0.80-1.10)compounds with different boron-to-arsenic elemental molar ratios were synthesized by a high-pressure and high-temperature sintering method.Compared with other ambient-pressure synthesis methods,high pressure can significantly promote the reaction speed as well as the reaction yield.As the content of arsenic increases from x=0.91 to 1.10,the thermal conductivity of BAsx gradually increases from 53 to 65 W·m-1·K-1.Furthermore,the temperature dependence of thermal conductivities of these samples reveals an Umklapp scattering due to the increasing phonon population.This work provides a highly efficient method for polycrystalline BAs synthesis.
