Floating zone method with optical radiation heating was applied to growing a class of R2PdSi3（R=Pr,Tb and Gd） single crystals due to its containerless melting and high stability of the floating zone.One serious prob...Floating zone method with optical radiation heating was applied to growing a class of R2PdSi3（R=Pr,Tb and Gd） single crystals due to its containerless melting and high stability of the floating zone.One serious problem during the single crystal growth,precipitates of secondary phases,was discussed from the following four parts：precipitates from the raw materials and preparation process,precipitates formed during the growing process,precipitates in the melts and precipitates in the grown crystals.Annealing treatment and composition shift can effectively reduce the precipitates which are not formed during the crystallization but precipitated on post-solidification cooling from the as-grown crystal matrix because of the retrograde solubility of Si.展开更多
[Objective] The aim was to research effects of substrate complexing light rare earth on growth, Cd absorption and organ distribution of sweet pepper to pro- vide references for development of rhizosphere regulation pr...[Objective] The aim was to research effects of substrate complexing light rare earth on growth, Cd absorption and organ distribution of sweet pepper to pro- vide references for development of rhizosphere regulation products in farmland seri- ously polluted. [Method] In the test, effects of substrate cakes （at the same size） and light rare earth （in different doses） on growth, Cd absorption and distribution of green peppers under stress from Cd were explored with a pot experiment. [Result] When 40 mg/kg of rare earth was added into a substrate cake, plant height of pep- per seedlings and the dry weight increased by 21.52% and 11.11%, compared with control group; when Cd was at 5.19 mg/kg （a highly graded pollution）, the shoot biomass, olant biomass and dry weight of fruits all enhanced significantly, but root system changed little in the groups where substrate cakes were saved, compared with the group where the substrate cake was washed away. No matter RE was added into substrate cakes or not, root system was significantly inhibited by Cd stress （5.19 mg/kg）, but RE at proper dose improved growth of green pepper and had little effect on fruit yielding. In addition, RE had little inhibition on Cd content in roots. RE at 10 mg/kg promoted Cd contents in stems and leaves, but reduced the content in fruits substantially. The regressive equation of Cd content and rare dose in leaves was as follows： y=4E-05x%0.009 6x＋0.655 6, FF=0.542 6; the regression equations of Cd content in root, stem and fruit did not make sense. [Conclusion] The experiment lays foundation for further research on heavy metals rhizosphere complexing controlling.展开更多
Based on the biogeochemical studies on nutrient elements in the Changjiang estuary, the main results and recent progresses are reviewed in this paper, such as the nutrient fluxes into the sea, the mixing behaviors, th...Based on the biogeochemical studies on nutrient elements in the Changjiang estuary, the main results and recent progresses are reviewed in this paper, such as the nutrient fluxes into the sea, the mixing behaviors, the distribution characteristics and transportation as well as the biogeochemical behaviors of nutrients in the plume frontal region. The exploring directions and research emphases in the future are proposed.展开更多
Effects of different lead compounds, PbCl2, Pb(NO3)2 and Pb(OAc)2, on the rice growth and uptake of lead and some microelements by wetland rice were studied. The results showed that the seed germination, rice seedling...Effects of different lead compounds, PbCl2, Pb(NO3)2 and Pb(OAc)2, on the rice growth and uptake of lead and some microelements by wetland rice were studied. The results showed that the seed germination, rice seedling growth, chlorophyl content, grain yield and uptake of Pb, Cu, Zn, Fe and Mn by rice plant were affected by the chemical forms of Pb compounds added in soil to a certain degree. The germination rate and the amount of chlorophyl decreased remarkably with increasing Pb concentration, the root extension was restrained obviously by the presence of Pb, and the effect of PbCl2 was more evident than that of Pb(NO3)2 or Pb(OAc)2. The pot incubation test with yellow brown soil and red soil showed that there was no significant regularity in effect of Pb on grain yield, but the difference in the influence of various Pb compounds on yield was clearer. The effect on the amount of Pb in straw and brown rice was in the sequence of Pb(NO3)2> Pb(OAc)2> PbCl2. In case the content of Pb in brown rice was 0.5 mg/ kg, the relative loading capacities of yellow brown soil for Pb added as PbCl2, Pb(OAc)2 and Pb(NO3)2 were 100, 90 and 60 respectively. Pb uptake by wetland rice was closely related to the chemical species of Pb in soil, but there was no comparability among chemical forms of different Pb compounds in the same soil. The uptake of Cu, Zn, Fe and Mn by wetland rice was markedly affected by the addition of Pb, and different Pb compounds varied in their impacts on the uptake of other metals by different organs of wetland rice, e.g. the concentration of Fe in root increased significantly (r = 0.92), while opposite was true for Fe in brown rice (r =-0.92) due to the application of Pb(OAc), in soil. These results demonstrate that the effect of accompanying anions of Pb on the physiological and biochemical processes of wetland rice was rather complex.展开更多
Using general multi-phase-field model,detailed microstructures corresponding to different initial lamellar sets were simulated in a binary eutectic alloy with an asymmetric phase diagram.The simulation results show th...Using general multi-phase-field model,detailed microstructures corresponding to different initial lamellar sets were simulated in a binary eutectic alloy with an asymmetric phase diagram.The simulation results show that regular or unstable oscillating lamellar structures depend on the initial lamellar widths of two solid phases.A lamellar morphology map associating with the initial widths has been derived,which is capable of showing the condition of forming various lamella structures.For instance,a regular lamella was formed with fast solidification while large lamella resulted from disorder growth with low interfacial velocity. The investigated interface velocities indicate that with fast solidification to form regular lamella,a disorder growth manner or a large lamellar spacing causes a low interface velocity.These results are in good agreement with those proposed by Jackson-Hunt model.展开更多
Using elementary integral method, a complete classification of all possible exact traveling wave solutions to （3＋1）-dimensional Nizhnok-Novikov-Veselov equation is given. Some solutions are new.
During the crystal grown by VBM, the solid/liquid interface configurations greatly influence the quality of as-grown crystals. In this paper, finite element method (FEM) was used to simulate the growth process of CdZn...During the crystal grown by VBM, the solid/liquid interface configurations greatly influence the quality of as-grown crystals. In this paper, finite element method (FEM) was used to simulate the growth process of CdZnTe crystal. The effects of different crucible moving rates and temperature gradient of adiabatic zone on crystal growth rate and solid-liquid interface configuration were studied as well. Simulation results show that when crucible moves at the rate of about 1mm/h, which is nearly equal to crystal growth rate, nearly flat solid/liquid interface and little variation of axial temperature gradient near it can be attained, which are well consistent with the results of experiments. CdZnTe crystal with low dislocation density can be obtained by employing appropriate crucible moving rate during the crystal growth process.展开更多
Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ...Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ordinary solution techniques lead to instability near the limit points and also have problems in case of snap-through and snap-back. Thus they fail to predict the complete load-displacement response. The arc-length method serves the purpose well in principle, received wide acceptance in finite element analysis, and has been used extensively. However modifications to the basic idea are vital to meet the particular needs of the analysis. This paper reviews some of the recent developments of the method in the last two decades, with particular emphasis on nonlinear finite element analysis of reinforced concrete structures.展开更多
基金Project (2008629045) supported by the China Scholarship Council (Constructing High-Level University Project)
文摘Floating zone method with optical radiation heating was applied to growing a class of R2PdSi3（R=Pr,Tb and Gd） single crystals due to its containerless melting and high stability of the floating zone.One serious problem during the single crystal growth,precipitates of secondary phases,was discussed from the following four parts：precipitates from the raw materials and preparation process,precipitates formed during the growing process,precipitates in the melts and precipitates in the grown crystals.Annealing treatment and composition shift can effectively reduce the precipitates which are not formed during the crystallization but precipitated on post-solidification cooling from the as-grown crystal matrix because of the retrograde solubility of Si.
基金Special Fund for Scientific Research for the Public Interest(20100314)National Key Technology R&D Program(2007BAD89B03)Enterprise Service Program by Technicians in the Ministry of Science and Technology(2009GJA00026)~~
文摘[Objective] The aim was to research effects of substrate complexing light rare earth on growth, Cd absorption and organ distribution of sweet pepper to pro- vide references for development of rhizosphere regulation products in farmland seri- ously polluted. [Method] In the test, effects of substrate cakes （at the same size） and light rare earth （in different doses） on growth, Cd absorption and distribution of green peppers under stress from Cd were explored with a pot experiment. [Result] When 40 mg/kg of rare earth was added into a substrate cake, plant height of pep- per seedlings and the dry weight increased by 21.52% and 11.11%, compared with control group; when Cd was at 5.19 mg/kg （a highly graded pollution）, the shoot biomass, olant biomass and dry weight of fruits all enhanced significantly, but root system changed little in the groups where substrate cakes were saved, compared with the group where the substrate cake was washed away. No matter RE was added into substrate cakes or not, root system was significantly inhibited by Cd stress （5.19 mg/kg）, but RE at proper dose improved growth of green pepper and had little effect on fruit yielding. In addition, RE had little inhibition on Cd content in roots. RE at 10 mg/kg promoted Cd contents in stems and leaves, but reduced the content in fruits substantially. The regressive equation of Cd content and rare dose in leaves was as follows： y=4E-05x%0.009 6x＋0.655 6, FF=0.542 6; the regression equations of Cd content in root, stem and fruit did not make sense. [Conclusion] The experiment lays foundation for further research on heavy metals rhizosphere complexing controlling.
基金The paper was supported by the National Science Foundation of China projects(40076022)the National Basic Research Program of China(001CB409703).
文摘Based on the biogeochemical studies on nutrient elements in the Changjiang estuary, the main results and recent progresses are reviewed in this paper, such as the nutrient fluxes into the sea, the mixing behaviors, the distribution characteristics and transportation as well as the biogeochemical behaviors of nutrients in the plume frontal region. The exploring directions and research emphases in the future are proposed.
文摘Effects of different lead compounds, PbCl2, Pb(NO3)2 and Pb(OAc)2, on the rice growth and uptake of lead and some microelements by wetland rice were studied. The results showed that the seed germination, rice seedling growth, chlorophyl content, grain yield and uptake of Pb, Cu, Zn, Fe and Mn by rice plant were affected by the chemical forms of Pb compounds added in soil to a certain degree. The germination rate and the amount of chlorophyl decreased remarkably with increasing Pb concentration, the root extension was restrained obviously by the presence of Pb, and the effect of PbCl2 was more evident than that of Pb(NO3)2 or Pb(OAc)2. The pot incubation test with yellow brown soil and red soil showed that there was no significant regularity in effect of Pb on grain yield, but the difference in the influence of various Pb compounds on yield was clearer. The effect on the amount of Pb in straw and brown rice was in the sequence of Pb(NO3)2> Pb(OAc)2> PbCl2. In case the content of Pb in brown rice was 0.5 mg/ kg, the relative loading capacities of yellow brown soil for Pb added as PbCl2, Pb(OAc)2 and Pb(NO3)2 were 100, 90 and 60 respectively. Pb uptake by wetland rice was closely related to the chemical species of Pb in soil, but there was no comparability among chemical forms of different Pb compounds in the same soil. The uptake of Cu, Zn, Fe and Mn by wetland rice was markedly affected by the addition of Pb, and different Pb compounds varied in their impacts on the uptake of other metals by different organs of wetland rice, e.g. the concentration of Fe in root increased significantly (r = 0.92), while opposite was true for Fe in brown rice (r =-0.92) due to the application of Pb(OAc), in soil. These results demonstrate that the effect of accompanying anions of Pb on the physiological and biochemical processes of wetland rice was rather complex.
基金Projects(50771041,50801019)supported by the National Natural Science Foundation of ChinaProject(20080430909)supported by China Postdoctoral Science FoundationProject(HITQNJS.2008.018)supported by Development Program for Outstanding Young Teachers in Harbin Institute of Technology,China
文摘Using general multi-phase-field model,detailed microstructures corresponding to different initial lamellar sets were simulated in a binary eutectic alloy with an asymmetric phase diagram.The simulation results show that regular or unstable oscillating lamellar structures depend on the initial lamellar widths of two solid phases.A lamellar morphology map associating with the initial widths has been derived,which is capable of showing the condition of forming various lamella structures.For instance,a regular lamella was formed with fast solidification while large lamella resulted from disorder growth with low interfacial velocity. The investigated interface velocities indicate that with fast solidification to form regular lamella,a disorder growth manner or a large lamellar spacing causes a low interface velocity.These results are in good agreement with those proposed by Jackson-Hunt model.
基金The project supported by Scientific Research Fund of Heilongjiang Province of China under Grant No. 11511008The author would like to thank referees for their valuable suggestions.
文摘Using elementary integral method, a complete classification of all possible exact traveling wave solutions to （3＋1）-dimensional Nizhnok-Novikov-Veselov equation is given. Some solutions are new.
基金National Natural Science Foundation of China (10175040) Foundation of Shanghai Education Committee(02AK30) Key Subject Construction Project (Material Science) of Shanghai Education Committee
文摘During the crystal grown by VBM, the solid/liquid interface configurations greatly influence the quality of as-grown crystals. In this paper, finite element method (FEM) was used to simulate the growth process of CdZnTe crystal. The effects of different crucible moving rates and temperature gradient of adiabatic zone on crystal growth rate and solid-liquid interface configuration were studied as well. Simulation results show that when crucible moves at the rate of about 1mm/h, which is nearly equal to crystal growth rate, nearly flat solid/liquid interface and little variation of axial temperature gradient near it can be attained, which are well consistent with the results of experiments. CdZnTe crystal with low dislocation density can be obtained by employing appropriate crucible moving rate during the crystal growth process.
文摘Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ordinary solution techniques lead to instability near the limit points and also have problems in case of snap-through and snap-back. Thus they fail to predict the complete load-displacement response. The arc-length method serves the purpose well in principle, received wide acceptance in finite element analysis, and has been used extensively. However modifications to the basic idea are vital to meet the particular needs of the analysis. This paper reviews some of the recent developments of the method in the last two decades, with particular emphasis on nonlinear finite element analysis of reinforced concrete structures.
