Polycrystalline and epitaxial CoSi 2 films are formed on the n-Si (111) substrates by solid state reaction of the as-deposited Co single-layer and Co/Ti bilayer with Si,respectively at different annealing phase.The C...Polycrystalline and epitaxial CoSi 2 films are formed on the n-Si (111) substrates by solid state reaction of the as-deposited Co single-layer and Co/Ti bilayer with Si,respectively at different annealing phase.The CoSi 2/Si Schottky contacts are measured with the current-voltage and capacitance-voltage (I-V/C-V) techniques within the range of temperature from 90K to room temperature.The measured I-V characteristics have been analyzed with a model based on the inhomogeneity in Schottky barrier height,i.e.,at high temperatures (≥~200K) or low temperatures but with a large bias,the I-V curves can be described by using the thermionic emission theory with a Gaussian distributed barrier height over the whole junction,while at low temperatures and with a small bias,the current is dominated by some small patches with low barrier height.It results in a plateau-like section in the low temperature I-V curves around 10 -7 A.At room temperature,the barrier height of polycrystalline CoSi 2/Si deduced from the I-V curve is about 0 57eV.For epitaxial CoSi 2,the barrier height depends on its final annealing temperature and increases from 0 54eV to 0 60eV with the annealing temperature increasing from 700℃ to 900℃.展开更多
Metal organic frameworks(MOFs) are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separa...Metal organic frameworks(MOFs) are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separation and recycling after catalytic reactions are difficult.The integration of MOFs with magnetic nanoparticles could facilitate their recovery and separation.Especially,the shell thickness of the core-shell structured composites is controllable.In this study,amino-functionalized Fe3O4@Cu3(BTC)2 was fabricated by a stepwise assembly method and its catalytic performance in Knoevenagel condensation was investigated.The results demonstrated that the magnetic hybrid material exhibited a core-shell structure,with a shell thickness of about 2 00 nm.Furthermore,it not only exhibited high catalytic activity,but remarkably,it could also be easily recovered magnetically and recycled without obvious loss of catalytic efficiency after three cycles.展开更多
separation is an attractive alternative to filtration or centrifugation for separating solid catalysts from a liquid phase, Here, core-shell Fe3O4@UiO-66-NH2 nanohybrids with well-defined structures were constructed b...separation is an attractive alternative to filtration or centrifugation for separating solid catalysts from a liquid phase, Here, core-shell Fe3O4@UiO-66-NH2 nanohybrids with well-defined structures were constructed by dispersing magnets in a dimethylformamide (DMF) solution con- taining two metal-organic framework (MOF) precursors, namely ZrCI4 and 2-aminobenzenetricar- boxylic acid. This method is simpler and more efficient than previously reported step-by-step method in which magnets were consecutively dispersed in DMF solutions each containing one MOF precursor, and the obtained Fe304@UiO-66-NH2 with three assembly cycles has a higher degree of crystallinity and porosiW. The core-shell Fe3O4@UiO-66-NH2 is highly active and selective in Knoevenagel condensations because of the bifunctionality of UiO-66-NH2 and better mass transfer in the nano-sized shells. It also has good recycling stability, and can be recovered magnetically and reused at least four times without significant loss of catalytic activity and framework integrity. The effects of substitution on the reactivity of benzaldehyde and of substrate size were also investigated.展开更多
AIM: To evaluate the effect of single nucleotide poly- morphisms of interleukin (IL)-28B, rs12979860 on progression and treatment response in chronic hepatitis C. METHODS: Patients (n = 64; 37 men, 27 women; mean...AIM: To evaluate the effect of single nucleotide poly- morphisms of interleukin (IL)-28B, rs12979860 on progression and treatment response in chronic hepatitis C. METHODS: Patients (n = 64; 37 men, 27 women; mean age, 44 + 12 years) with chronic hepatitis C, genotype 1, received treatment with peg-interferon plus ribavirin. Genotyping of rs12979860 was per- formed on peripheral blood DNA. Histopathological assessment of necroinflammatory grade and fibrosis stage were scored using the METAVIR system on a liver biopsy sample before treatment. Serum viral load, ami- notransferase activity, and insulin level were measured. Insulin resistance index, body mass index, waist/hip ratio, percentage of body fat and fibrosis progression rate were calculated. Applied dose of interferon and ribavirin, platelet and neutrophil count and hemoglobin level were measured. RESULTS: A sustained virological response (SVR) was significantly associated with IL28B polymorphism (CC vs -l-r allele: odds ratio (OR), 25; CC vs CT allele: OR, 5.4), inflammation activity (G 〈 1 vs G 〉 1: OR, 3.9), fibrosis (F 〈 1 vs F 〉 1: OR, 5.9), platelet count (〉 200 × 109/L vs 〈 200 ×109/L: OR, 4.7; OR in patients with genotype CT: 12.8), fatty liver (absence vs presence of steatosis: OR, 4.8), insulin resistance index (〈 2.5 vs 〉 2.5: OR, 3.9), and baseline HCV viral load (〈 106 IU/mL vs 〉 106 IU/mL: OR, 3.0). There was no association with age, sex, aminotransferases activity, body mass index, waist/hip ratio, or percentage body fat. There was borderline significance (P = 0.064) of increased fibrosis in patients with the I-I allele, and no differences in the insulin resistance index between groups of patients with CC, CT and -IF alleles (P = 0.12). Spearman's rank correlation coefficient between insulin resistance and stage of fibrosis and body mass index was r = 0.618 and r = 0.605, respectively (P 〈 0.001). Significant dif- ferences were found in the insulin resistance index (P = 0.01) between patients with and without steatosis. Patients with the C-I- allele and absence of a SVR had a higher incidence of requiring threshold dose reduction of interferon (P = 0.07). CONCLUSION: IL28B variation is the strongest host factor not related to insulin resistance that determines outcome of antiviral therapy. Baseline platelet count predicts the outcome of antiviral therapy in CT allele patients.展开更多
The design of optimal heterogeneous catalysts for N_(2)-to-NH_(3) conversion is often dictated by the scaling relations,which result in a volcano curve that poses a limit on the catalytic performance.Herein,we reveal ...The design of optimal heterogeneous catalysts for N_(2)-to-NH_(3) conversion is often dictated by the scaling relations,which result in a volcano curve that poses a limit on the catalytic performance.Herein,we reveal a bowl active site that can break the scaling relations,through investigating the catalytic mechanisms of N_(2)-to-NH_(3) conversion on the lanthanide intermetallic electride catalyst LaRuSi by first-principles modeling.This bowl active site,composed of four surface La cations and one subsurface Si atom rich in electrons,plays the key role in enabling efficient catalysis.With adaptive electrostatic and orbital interactions,the bowl active site promotes the adsorption and activation of N_(2) that delivers facile cleavage of N-N bond,while destabilizes the adsorptions of ^(*)NH_(x)(x=1,2,3)species,which facilitates the release of the final NH_(3) product.By comparison with other electride catalysts isostructural to LaRuSi,we confirm the breaking of scaling relations between the adsorptions of ^(*)NH_(x) species and that of^(*)N on the bowl active site.Thus,this bowl active site presents a design concept that breaks the scaling relations for highly efficient heterogeneous catalysis of N_(2)-to-NH_(3) conversion.展开更多
A series of polysubstituted tetrahydropyrimidines were synthesized in moderate to good yields via a one-pot, four-component reaction of an alkyne, formaldehyde, and amines in solid media acidic Al2O3. The advantages o...A series of polysubstituted tetrahydropyrimidines were synthesized in moderate to good yields via a one-pot, four-component reaction of an alkyne, formaldehyde, and amines in solid media acidic Al2O3. The advantages of this protocol include mild reaction conditions, broad substrate scope, and environmentally friendly reaction media.展开更多
Cadmium sulfide(Cd S) buffer layers with the scale of 10 cm×10 cm are deposited by chemical bath deposition(CBD) with different temperatures and thiourea concentrations under low ammonia condition.There are obvio...Cadmium sulfide(Cd S) buffer layers with the scale of 10 cm×10 cm are deposited by chemical bath deposition(CBD) with different temperatures and thiourea concentrations under low ammonia condition.There are obvious hexagonal phases and cubic phases in Cd S thin films under the conditions of low temperature and high thiourea concentration.The main reason is that the heterogeneous reaction is dominant for homogeneous reaction.At low temperature,Cd S thin films with good uniformity and high transmittance are deposited by adjusting the thiourea concentration,and there is almost no precipitation in reaction solution.In addition,the low temperature is desired in assembly line.The transmittance and the band gap of Cd S thin films are above 80% and about 2.4 e V,respectively.These films are suitable for the buffer layers of large-scale Cu(In,Ga)Se2(CIGS) solar cells.展开更多
文摘Polycrystalline and epitaxial CoSi 2 films are formed on the n-Si (111) substrates by solid state reaction of the as-deposited Co single-layer and Co/Ti bilayer with Si,respectively at different annealing phase.The CoSi 2/Si Schottky contacts are measured with the current-voltage and capacitance-voltage (I-V/C-V) techniques within the range of temperature from 90K to room temperature.The measured I-V characteristics have been analyzed with a model based on the inhomogeneity in Schottky barrier height,i.e.,at high temperatures (≥~200K) or low temperatures but with a large bias,the I-V curves can be described by using the thermionic emission theory with a Gaussian distributed barrier height over the whole junction,while at low temperatures and with a small bias,the current is dominated by some small patches with low barrier height.It results in a plateau-like section in the low temperature I-V curves around 10 -7 A.At room temperature,the barrier height of polycrystalline CoSi 2/Si deduced from the I-V curve is about 0 57eV.For epitaxial CoSi 2,the barrier height depends on its final annealing temperature and increases from 0 54eV to 0 60eV with the annealing temperature increasing from 700℃ to 900℃.
基金supported by the National Natural Science Foundation of China (21203017)the Open Fund of State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences(N-11-3)+1 种基金the Program for Liaoning Excellent Talents in University (LNET)the Fundamental Research Funds for the Central Universities (DC201502020304)~~
文摘Metal organic frameworks(MOFs) are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separation and recycling after catalytic reactions are difficult.The integration of MOFs with magnetic nanoparticles could facilitate their recovery and separation.Especially,the shell thickness of the core-shell structured composites is controllable.In this study,amino-functionalized Fe3O4@Cu3(BTC)2 was fabricated by a stepwise assembly method and its catalytic performance in Knoevenagel condensation was investigated.The results demonstrated that the magnetic hybrid material exhibited a core-shell structure,with a shell thickness of about 2 00 nm.Furthermore,it not only exhibited high catalytic activity,but remarkably,it could also be easily recovered magnetically and recycled without obvious loss of catalytic efficiency after three cycles.
基金supported by the National Natural Science Foundation of China (21203017)Open Fund of State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences (N-11-3)+1 种基金Program for Liaoning Excellent Talents in University (LNET)the Funda-mental Research Funds for the Central Universities (DC201502020304)~~
文摘separation is an attractive alternative to filtration or centrifugation for separating solid catalysts from a liquid phase, Here, core-shell Fe3O4@UiO-66-NH2 nanohybrids with well-defined structures were constructed by dispersing magnets in a dimethylformamide (DMF) solution con- taining two metal-organic framework (MOF) precursors, namely ZrCI4 and 2-aminobenzenetricar- boxylic acid. This method is simpler and more efficient than previously reported step-by-step method in which magnets were consecutively dispersed in DMF solutions each containing one MOF precursor, and the obtained Fe304@UiO-66-NH2 with three assembly cycles has a higher degree of crystallinity and porosiW. The core-shell Fe3O4@UiO-66-NH2 is highly active and selective in Knoevenagel condensations because of the bifunctionality of UiO-66-NH2 and better mass transfer in the nano-sized shells. It also has good recycling stability, and can be recovered magnetically and reused at least four times without significant loss of catalytic activity and framework integrity. The effects of substitution on the reactivity of benzaldehyde and of substrate size were also investigated.
文摘AIM: To evaluate the effect of single nucleotide poly- morphisms of interleukin (IL)-28B, rs12979860 on progression and treatment response in chronic hepatitis C. METHODS: Patients (n = 64; 37 men, 27 women; mean age, 44 + 12 years) with chronic hepatitis C, genotype 1, received treatment with peg-interferon plus ribavirin. Genotyping of rs12979860 was per- formed on peripheral blood DNA. Histopathological assessment of necroinflammatory grade and fibrosis stage were scored using the METAVIR system on a liver biopsy sample before treatment. Serum viral load, ami- notransferase activity, and insulin level were measured. Insulin resistance index, body mass index, waist/hip ratio, percentage of body fat and fibrosis progression rate were calculated. Applied dose of interferon and ribavirin, platelet and neutrophil count and hemoglobin level were measured. RESULTS: A sustained virological response (SVR) was significantly associated with IL28B polymorphism (CC vs -l-r allele: odds ratio (OR), 25; CC vs CT allele: OR, 5.4), inflammation activity (G 〈 1 vs G 〉 1: OR, 3.9), fibrosis (F 〈 1 vs F 〉 1: OR, 5.9), platelet count (〉 200 × 109/L vs 〈 200 ×109/L: OR, 4.7; OR in patients with genotype CT: 12.8), fatty liver (absence vs presence of steatosis: OR, 4.8), insulin resistance index (〈 2.5 vs 〉 2.5: OR, 3.9), and baseline HCV viral load (〈 106 IU/mL vs 〉 106 IU/mL: OR, 3.0). There was no association with age, sex, aminotransferases activity, body mass index, waist/hip ratio, or percentage body fat. There was borderline significance (P = 0.064) of increased fibrosis in patients with the I-I allele, and no differences in the insulin resistance index between groups of patients with CC, CT and -IF alleles (P = 0.12). Spearman's rank correlation coefficient between insulin resistance and stage of fibrosis and body mass index was r = 0.618 and r = 0.605, respectively (P 〈 0.001). Significant dif- ferences were found in the insulin resistance index (P = 0.01) between patients with and without steatosis. Patients with the C-I- allele and absence of a SVR had a higher incidence of requiring threshold dose reduction of interferon (P = 0.07). CONCLUSION: IL28B variation is the strongest host factor not related to insulin resistance that determines outcome of antiviral therapy. Baseline platelet count predicts the outcome of antiviral therapy in CT allele patients.
文摘The design of optimal heterogeneous catalysts for N_(2)-to-NH_(3) conversion is often dictated by the scaling relations,which result in a volcano curve that poses a limit on the catalytic performance.Herein,we reveal a bowl active site that can break the scaling relations,through investigating the catalytic mechanisms of N_(2)-to-NH_(3) conversion on the lanthanide intermetallic electride catalyst LaRuSi by first-principles modeling.This bowl active site,composed of four surface La cations and one subsurface Si atom rich in electrons,plays the key role in enabling efficient catalysis.With adaptive electrostatic and orbital interactions,the bowl active site promotes the adsorption and activation of N_(2) that delivers facile cleavage of N-N bond,while destabilizes the adsorptions of ^(*)NH_(x)(x=1,2,3)species,which facilitates the release of the final NH_(3) product.By comparison with other electride catalysts isostructural to LaRuSi,we confirm the breaking of scaling relations between the adsorptions of ^(*)NH_(x) species and that of^(*)N on the bowl active site.Thus,this bowl active site presents a design concept that breaks the scaling relations for highly efficient heterogeneous catalysis of N_(2)-to-NH_(3) conversion.
基金Funds of Natural Science Foundation of China(Grant No.21372019)
文摘A series of polysubstituted tetrahydropyrimidines were synthesized in moderate to good yields via a one-pot, four-component reaction of an alkyne, formaldehyde, and amines in solid media acidic Al2O3. The advantages of this protocol include mild reaction conditions, broad substrate scope, and environmentally friendly reaction media.
基金supported by the National High Technology Research and Development Program of China(No.2012AA050701)
文摘Cadmium sulfide(Cd S) buffer layers with the scale of 10 cm×10 cm are deposited by chemical bath deposition(CBD) with different temperatures and thiourea concentrations under low ammonia condition.There are obvious hexagonal phases and cubic phases in Cd S thin films under the conditions of low temperature and high thiourea concentration.The main reason is that the heterogeneous reaction is dominant for homogeneous reaction.At low temperature,Cd S thin films with good uniformity and high transmittance are deposited by adjusting the thiourea concentration,and there is almost no precipitation in reaction solution.In addition,the low temperature is desired in assembly line.The transmittance and the band gap of Cd S thin films are above 80% and about 2.4 e V,respectively.These films are suitable for the buffer layers of large-scale Cu(In,Ga)Se2(CIGS) solar cells.