Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pe...Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pendula Roth） in Norwa are presented. The Norwegian National Forest Inventory （NFI） is used as data base for estimating the model parameters. The derived models are developed to enable spatially explicit and site sensitive tree height imputatio in forest inventories as well as future tree height predictions in growth and yield scenario simulations. Methods： Generalized additive mixed models （gamm） are employed to detect and quantify potentially non-linear effects of predictor variables. In doing so the quadratic mean diameter serves as longitudinal covariate since stand ag as measured in the NFI, shows only a weak correlation with a stands developmental status in Norwegian forests. Additionally the models can be locally calibrated by predicting random effects if measured height-diameter pairs are available. Based on the model selection of non-constraint models, shape constraint additive models （scare） were fit tc incorporate expert knowledge and intrinsic relationships by enforcing certain effect patterns like monotonicity. Results： Model comparisons demonstrate that the shape constraints lead to only marginal differences in statistical characteristics but ensure reasonable model predictions. Under constant constraints the developed models predict increasing tree heights with decreasing altitude, increasing soil depth and increasing competition pressure of a tree. / two-dimensional spatially structured effect of UTM-coordinates accounts for the potential effects of large scale spatial correlated covariates, which were not at our disposal. The main result of modelling the spatially structured effect is lower tree height prediction for coastal sites and with increasing latitude. The quadratic mean diameter affects both the level and the slope of the height-diameter curve and both effects are positive. Conclusions： In this investigation it is assumed that model effects in additive modelling of height-diameter curves which are unfeasible and too wiggly from an expert point of view are a result of quantitatively or qualitatively limited data bases. However, this problem can be regarded not to be specific to our investigation but more general since growth and yield data that are balanced over the whole data range with respect to all combinations of predictor variables are exceptional cases. Hence, scare may provide methodological improvements in several applications by combining the flexibility of additive models with expert knowledge.展开更多
Colloidal silver nanoparticles were prepared by reducing silver nitrate with oxalic acid in presence of cetyltrimethylammonium bromide (CTAB). The synthesized silver particles show an intense surface plasmon band in t...Colloidal silver nanoparticles were prepared by reducing silver nitrate with oxalic acid in presence of cetyltrimethylammonium bromide (CTAB). The synthesized silver particles show an intense surface plasmon band in the visible region. The work reported in this paper describes the effect of concentration of various additives (NaCl, NaBr, NaNO3, Na2SO4 and NaH2PO4) and ammonia on the growth and stability of Ag-nanoparticles. In all the cases the rate decreases as the [electrolytes] or [ammonia] increases. The nature, polarizability and coordinating ability of the anions play vital roles for nucleus formation and the growth process, which subsequently form different size particles. Transmission electron microscopy, selected areas electron diffraction, and UV-visible spectroscopy have been employed to characterize Ag-nanoparticles. The effect of the following variables on the particle size and size distribution was investigated: the [oxalic acid], [CTAB] and [Ag+].The nanoparticles are stable in NaNO3 and NaH2PO4 solutions;but NaCl, NaBr and Na2SO4 causes their aggregation.展开更多
A new hexanuclear silver （I） compound 2 containing thiosemicarbazone with the group of benzene was synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analysis and fluorescence ...A new hexanuclear silver （I） compound 2 containing thiosemicarbazone with the group of benzene was synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analysis and fluorescence spectrum. The title compound crystallizes in triclinic, space group P with a = 11.611（3）, b = 15.610（5）, c = 15.624（7） , α = 113.942（6）, β = 104.520（6）, γ = 104.230（4）°, V = 2304.1（14） 3, C60H77Ag6N22O4.5S6, Mr = 2018.02, Dc = 1.454 g/cm3, μ（MoKα） = 1.435 mm-1, F（000） = 1005, Z = 1, the final R = 0.0468 and wR = 0.1474 for 6608 observed reflections （I 2σ（I））. In the structure, the S atom of the ligand L2 （L2 = benzaldehyde thiosemicarbazone） served as a triply bridged chelator to connect the six silver atoms into a Ag6L26 cluster. The luminescence property of compound 2 was investigated at room temperature.展开更多
A series of acyls （Ac, Bz and Ts） were introduced regioselectively to the 2-hydroxyl in methyl and ally 3-O-benzyl-α-L-rhamnopyranosides mediated by silver（I） oxide in the presence of a catalytic amount of potass...A series of acyls （Ac, Bz and Ts） were introduced regioselectively to the 2-hydroxyl in methyl and ally 3-O-benzyl-α-L-rhamnopyranosides mediated by silver（I） oxide in the presence of a catalytic amount of potassium iodide in 56-78% yields.展开更多
The title complex,[Ag 2 （L1） 2 （Pyr）·2.5H 2 O] 1 （L1=6-amino-1-naphthalenesulfonate anion,Pyr=pyrazine）,has been synthesized and characterized by single-crystal X-ray diffraction analysis.It crystallizes in...The title complex,[Ag 2 （L1） 2 （Pyr）·2.5H 2 O] 1 （L1=6-amino-1-naphthalenesulfonate anion,Pyr=pyrazine）,has been synthesized and characterized by single-crystal X-ray diffraction analysis.It crystallizes in triclinic,space group P1,with a=7.339（5）,b=13.105（5）,c=14.097（5）,α=84.377（5）,β=76.921（5）,γ=79.628（5）°,V=1296.7（11） 3,C 48 H 50 Ag 4 N 8 O 17 S 4,M r=1570.68,Z=1,D c=2.011 g/cm 3,μ=1.732 mm-1,F（000）=782,S=1.148,the final R=0.0436 and wR=0.1181 for 4130 observer reflections （I 2σ（Ⅰ））.Compound 1 shows a rare one-dimensional （1D） double chain,and the chains are further connected through secondary bonding,hydrogen bonds,and π-π interactions to generate a three-dimensional （3D） supramolecular structure.The luminescent property of 1 was also studied in the solid state at room temperture.展开更多
The cyclic voltammetry(CV) and the square wave technique were used for the investigations of thallium(Ⅰ) underpotential deposition(UPD) on the silver electrode. A solution of 10 \{mmol/L\} HClO 4+10 mmol/L NaCl was s...The cyclic voltammetry(CV) and the square wave technique were used for the investigations of thallium(Ⅰ) underpotential deposition(UPD) on the silver electrode. A solution of 10 \{mmol/L\} HClO 4+10 mmol/L NaCl was selected as the supporting electrolyte. The calibration plots for Tl(Ⅰ) concentration in the range of 2×10 -9 -1×10 -7 mol/L were obtained. The detection limit was 5×10 -10 mol/L. For the solutions of 4 0×10 -9 mol/L thallium added before the urine sample pretreatment procedure, the average recovery was 105 6% with a relative standard deviation(RSD) of 15 5%.展开更多
Two novel coordination compounds, [Zn（CBPP）2（H2O）2]·3H2O（1） and[Ag（CBPP）·2H2O]（2）（HCBPP = 1-（4？-carboxylatobenzyl）-3-（pyrazin-2-yl）pyrazole）, were hydrothermally synthesized and characterize...Two novel coordination compounds, [Zn（CBPP）2（H2O）2]·3H2O（1） and[Ag（CBPP）·2H2O]（2）（HCBPP = 1-（4？-carboxylatobenzyl）-3-（pyrazin-2-yl）pyrazole）, were hydrothermally synthesized and characterized. Compound 1 crystallizes in monoclinic, space group C2 with a = 26.221（4）, b = 8.4211（7）, c = 14.295（3）A, β = 114.561（8）°, V = 2705.9（2） A3, Dc = 1.587 g/cm3, C28H28Cl2N8O9 Zn, Mr = 685.97 F（000） = 1416, μ（Mo Kα） = 0.926 mm-1, Z = 4, R = 0.0287, w R = 0.1076 for 2818 observed reflections（I 〉 2σ（I））, and R = 0.0300, w R = 0.1110 for all data. In 1, each deprotonated CBPP-ligand with a bidentate coordination mode connects two Zn（II） atoms to generate a 1D helical chain along the b axis. The adjacent chains intersect with each other through hinged Zn（II） ions to build up an interesting two-dimensional network. Compound 2 crystallizes in monoclinic, space group P21/n with a = 6.3544（1）, b = 11.7195（3）, c = 19.3188（4）A, β = 94.297（2）°, V = 1434.64（5） A3, Dc = 1.894 g/cm3, C14H13 Ag N4O4, Mr = 409.15 F（000） = 816, μ（Mo Kα） = 11.536 mm-1, Z = 4, R = 0.0456 and w R = 0.1184 for 2402 observed reflections（I 〉 2σ（I））, and R = 0.0517, w R = 0.1275 for all data. In 2, each ligand binds two Ag（I） atoms in a tridentate coordination mode to form an infinite zigzag chain. Their thermal and photoluminescent properties were also investigated.展开更多
A novel method for determination of SudanⅠ in food by single scan polarography has been developed in this paper.It was found that a well-shape second derivation polarographic wave was observed at peak potential Ep-0....A novel method for determination of SudanⅠ in food by single scan polarography has been developed in this paper.It was found that a well-shape second derivation polarographic wave was observed at peak potential Ep-0.79V(vs.SCE)in the mediums of sodium tetraborate and ethanol.The peak current for the wave was proportional to concentration of Sudan I.The linear range was 0.1μg/mL^1.6μg/mL.The coefficient of correlation was 0.9983.The detection limit of the method was 0.025μg/mL.Its relative standard deviation(RSD) was ≤1.1%(n=6).Average recoveries of blank were over the range of 88.0%～101.0% and average recoveries of pepper samples were over the range of 91.0%～117.4%.The proposed method is rapid,simple,accurate and highly sensitive,which provided the new gist to improving and perfecting the method for determination of SudanⅠ,and possessed a significant practical value.展开更多
Silver（Ⅰ） oxide was applied to the selective p-tosylation of hydroxyls of saccharide. The reaction of p-methylphenyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside（A） with a stoichiometric amount of p-toluenesulfo...Silver（Ⅰ） oxide was applied to the selective p-tosylation of hydroxyls of saccharide. The reaction of p-methylphenyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside（A） with a stoichiometric amount of p-toluenesulfonyl chloride（TsCl） in the presence of silver（Ⅰ） oxide and a catalytic amount of potassium iodide selectively led to the monotosylate derivative:p-methylphenyl 3-O-p-toluenesulfonyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside（B） in a high yield（97%）. A possible mechanism of the reaction is proposed. The rational reaction process is that at n（TsCl）∶n（Ag2O）∶n（A）∶n（KI）=1.2∶1.5∶1.0∶0.2, the mixture is stirred at room temperature for 8 h, 2.74 g（97%）B could be isolated from 2.0 g of compound A.展开更多
基金supported by the Norwegian Institute of Bioeconomy Research(NIBIO)
文摘Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pendula Roth） in Norwa are presented. The Norwegian National Forest Inventory （NFI） is used as data base for estimating the model parameters. The derived models are developed to enable spatially explicit and site sensitive tree height imputatio in forest inventories as well as future tree height predictions in growth and yield scenario simulations. Methods： Generalized additive mixed models （gamm） are employed to detect and quantify potentially non-linear effects of predictor variables. In doing so the quadratic mean diameter serves as longitudinal covariate since stand ag as measured in the NFI, shows only a weak correlation with a stands developmental status in Norwegian forests. Additionally the models can be locally calibrated by predicting random effects if measured height-diameter pairs are available. Based on the model selection of non-constraint models, shape constraint additive models （scare） were fit tc incorporate expert knowledge and intrinsic relationships by enforcing certain effect patterns like monotonicity. Results： Model comparisons demonstrate that the shape constraints lead to only marginal differences in statistical characteristics but ensure reasonable model predictions. Under constant constraints the developed models predict increasing tree heights with decreasing altitude, increasing soil depth and increasing competition pressure of a tree. / two-dimensional spatially structured effect of UTM-coordinates accounts for the potential effects of large scale spatial correlated covariates, which were not at our disposal. The main result of modelling the spatially structured effect is lower tree height prediction for coastal sites and with increasing latitude. The quadratic mean diameter affects both the level and the slope of the height-diameter curve and both effects are positive. Conclusions： In this investigation it is assumed that model effects in additive modelling of height-diameter curves which are unfeasible and too wiggly from an expert point of view are a result of quantitatively or qualitatively limited data bases. However, this problem can be regarded not to be specific to our investigation but more general since growth and yield data that are balanced over the whole data range with respect to all combinations of predictor variables are exceptional cases. Hence, scare may provide methodological improvements in several applications by combining the flexibility of additive models with expert knowledge.
文摘Colloidal silver nanoparticles were prepared by reducing silver nitrate with oxalic acid in presence of cetyltrimethylammonium bromide (CTAB). The synthesized silver particles show an intense surface plasmon band in the visible region. The work reported in this paper describes the effect of concentration of various additives (NaCl, NaBr, NaNO3, Na2SO4 and NaH2PO4) and ammonia on the growth and stability of Ag-nanoparticles. In all the cases the rate decreases as the [electrolytes] or [ammonia] increases. The nature, polarizability and coordinating ability of the anions play vital roles for nucleus formation and the growth process, which subsequently form different size particles. Transmission electron microscopy, selected areas electron diffraction, and UV-visible spectroscopy have been employed to characterize Ag-nanoparticles. The effect of the following variables on the particle size and size distribution was investigated: the [oxalic acid], [CTAB] and [Ag+].The nanoparticles are stable in NaNO3 and NaH2PO4 solutions;but NaCl, NaBr and Na2SO4 causes their aggregation.
基金supported by the Postdoctoral Science Foundation of Central South University
文摘A new hexanuclear silver （I） compound 2 containing thiosemicarbazone with the group of benzene was synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analysis and fluorescence spectrum. The title compound crystallizes in triclinic, space group P with a = 11.611（3）, b = 15.610（5）, c = 15.624（7） , α = 113.942（6）, β = 104.520（6）, γ = 104.230（4）°, V = 2304.1（14） 3, C60H77Ag6N22O4.5S6, Mr = 2018.02, Dc = 1.454 g/cm3, μ（MoKα） = 1.435 mm-1, F（000） = 1005, Z = 1, the final R = 0.0468 and wR = 0.1474 for 6608 observed reflections （I 2σ（I））. In the structure, the S atom of the ligand L2 （L2 = benzaldehyde thiosemicarbazone） served as a triply bridged chelator to connect the six silver atoms into a Ag6L26 cluster. The luminescence property of compound 2 was investigated at room temperature.
基金financially supported by the National Natural Science Foundation of China(No.30300434)the 0utstanding Youth Foundation of Sichuan Province(No.04ZQ026-039).
文摘A series of acyls （Ac, Bz and Ts） were introduced regioselectively to the 2-hydroxyl in methyl and ally 3-O-benzyl-α-L-rhamnopyranosides mediated by silver（I） oxide in the presence of a catalytic amount of potassium iodide in 56-78% yields.
基金supported by the Science Foundation of Suihua University (K1001005)
文摘The title complex,[Ag 2 （L1） 2 （Pyr）·2.5H 2 O] 1 （L1=6-amino-1-naphthalenesulfonate anion,Pyr=pyrazine）,has been synthesized and characterized by single-crystal X-ray diffraction analysis.It crystallizes in triclinic,space group P1,with a=7.339（5）,b=13.105（5）,c=14.097（5）,α=84.377（5）,β=76.921（5）,γ=79.628（5）°,V=1296.7（11） 3,C 48 H 50 Ag 4 N 8 O 17 S 4,M r=1570.68,Z=1,D c=2.011 g/cm 3,μ=1.732 mm-1,F（000）=782,S=1.148,the final R=0.0436 and wR=0.1181 for 4130 observer reflections （I 2σ（Ⅰ））.Compound 1 shows a rare one-dimensional （1D） double chain,and the chains are further connected through secondary bonding,hydrogen bonds,and π-π interactions to generate a three-dimensional （3D） supramolecular structure.The luminescent property of 1 was also studied in the solid state at room temperture.
文摘The cyclic voltammetry(CV) and the square wave technique were used for the investigations of thallium(Ⅰ) underpotential deposition(UPD) on the silver electrode. A solution of 10 \{mmol/L\} HClO 4+10 mmol/L NaCl was selected as the supporting electrolyte. The calibration plots for Tl(Ⅰ) concentration in the range of 2×10 -9 -1×10 -7 mol/L were obtained. The detection limit was 5×10 -10 mol/L. For the solutions of 4 0×10 -9 mol/L thallium added before the urine sample pretreatment procedure, the average recovery was 105 6% with a relative standard deviation(RSD) of 15 5%.
基金financially supported by the National Natural Science Foundation of China(21571034)the Natural Science Foundation of Fujian Province(2014J01033)
文摘Two novel coordination compounds, [Zn（CBPP）2（H2O）2]·3H2O（1） and[Ag（CBPP）·2H2O]（2）（HCBPP = 1-（4？-carboxylatobenzyl）-3-（pyrazin-2-yl）pyrazole）, were hydrothermally synthesized and characterized. Compound 1 crystallizes in monoclinic, space group C2 with a = 26.221（4）, b = 8.4211（7）, c = 14.295（3）A, β = 114.561（8）°, V = 2705.9（2） A3, Dc = 1.587 g/cm3, C28H28Cl2N8O9 Zn, Mr = 685.97 F（000） = 1416, μ（Mo Kα） = 0.926 mm-1, Z = 4, R = 0.0287, w R = 0.1076 for 2818 observed reflections（I 〉 2σ（I））, and R = 0.0300, w R = 0.1110 for all data. In 1, each deprotonated CBPP-ligand with a bidentate coordination mode connects two Zn（II） atoms to generate a 1D helical chain along the b axis. The adjacent chains intersect with each other through hinged Zn（II） ions to build up an interesting two-dimensional network. Compound 2 crystallizes in monoclinic, space group P21/n with a = 6.3544（1）, b = 11.7195（3）, c = 19.3188（4）A, β = 94.297（2）°, V = 1434.64（5） A3, Dc = 1.894 g/cm3, C14H13 Ag N4O4, Mr = 409.15 F（000） = 816, μ（Mo Kα） = 11.536 mm-1, Z = 4, R = 0.0456 and w R = 0.1184 for 2402 observed reflections（I 〉 2σ（I））, and R = 0.0517, w R = 0.1275 for all data. In 2, each ligand binds two Ag（I） atoms in a tridentate coordination mode to form an infinite zigzag chain. Their thermal and photoluminescent properties were also investigated.
文摘A novel method for determination of SudanⅠ in food by single scan polarography has been developed in this paper.It was found that a well-shape second derivation polarographic wave was observed at peak potential Ep-0.79V(vs.SCE)in the mediums of sodium tetraborate and ethanol.The peak current for the wave was proportional to concentration of Sudan I.The linear range was 0.1μg/mL^1.6μg/mL.The coefficient of correlation was 0.9983.The detection limit of the method was 0.025μg/mL.Its relative standard deviation(RSD) was ≤1.1%(n=6).Average recoveries of blank were over the range of 88.0%～101.0% and average recoveries of pepper samples were over the range of 91.0%～117.4%.The proposed method is rapid,simple,accurate and highly sensitive,which provided the new gist to improving and perfecting the method for determination of SudanⅠ,and possessed a significant practical value.
文摘Silver（Ⅰ） oxide was applied to the selective p-tosylation of hydroxyls of saccharide. The reaction of p-methylphenyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside（A） with a stoichiometric amount of p-toluenesulfonyl chloride（TsCl） in the presence of silver（Ⅰ） oxide and a catalytic amount of potassium iodide selectively led to the monotosylate derivative:p-methylphenyl 3-O-p-toluenesulfonyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside（B） in a high yield（97%）. A possible mechanism of the reaction is proposed. The rational reaction process is that at n（TsCl）∶n（Ag2O）∶n（A）∶n（KI）=1.2∶1.5∶1.0∶0.2, the mixture is stirred at room temperature for 8 h, 2.74 g（97%）B could be isolated from 2.0 g of compound A.
